Aggregator

Issued at 2100 UTC MON AUG 12 2019 000 WTPZ24 KNHC 122051 TCMEP4 TROPICAL STORM HENRIETTE FORECAST/ADVISORY NUMBER 4 NWS NATIONAL HURRICANE CENTER MIAMI FL EP092019 2100 UTC MON AUG 12 2019 THERE ARE NO COASTAL WATCHES OR WARNINGS IN EFFECT. TROPICAL STORM CENTER LOCATED NEAR 20.3N 113.1W AT 12/2100Z POSITION ACCURATE WITHIN 20 NM PRESENT MOVEMENT TOWARD THE WEST-NORTHWEST OR 290 DEGREES AT 11 KT ESTIMATED MINIMUM CENTRAL PRESSURE 1005 MB MAX SUSTAINED WINDS 35 KT WITH GUSTS TO 45 KT. 34 KT....... 20NE 20SE 20SW 20NW. 12 FT SEAS.. 30NE 30SE 0SW 0NW. WINDS AND SEAS VARY GREATLY IN EACH QUADRANT. RADII IN NAUTICAL MILES ARE THE LARGEST RADII EXPECTED ANYWHERE IN THAT QUADRANT. REPEAT...CENTER LOCATED NEAR 20.3N 113.1W AT 12/2100Z AT 12/1800Z CENTER WAS LOCATED NEAR 20.1N 112.6W FORECAST VALID 13/0600Z 20.9N 114.8W MAX WIND 30 KT...GUSTS 40 KT. FORECAST VALID 13/1800Z 21.6N 117.1W...POST-TROP/REMNT LOW MAX WIND 25 KT...GUSTS 35 KT. FORECAST VALID 14/0600Z 22.1N 119.7W...POST-TROP/REMNT LOW MAX WIND 20 KT...GUSTS 30 KT. FORECAST VALID 14/1800Z...DISSIPATED REQUEST FOR 3 HOURLY SHIP REPORTS WITHIN 300 MILES OF 20.3N 113.1W NEXT ADVISORY AT 13/0300Z $$ FORECASTER LATTO/PASCH

MD 1717 CONCERNING SEVERE POTENTIAL...TORNADO WATCH LIKELY FOR CENTRAL/SOUTHEAST IA...NORTHERN IL...FAR NORTHEAST MO
Mesoscale Discussion 1717 NWS Storm Prediction Center Norman OK 0346 PM CDT Mon Aug 12 2019 Areas affected...Central/southeast IA...Northern IL...Far northeast MO Concerning...Severe potential...Tornado Watch likely Valid 122046Z - 122215Z Probability of Watch Issuance...80 percent SUMMARY...Thunderstorms capable of primarily damaging winds and a few tornadoes are possible late this afternoon into the evening. Tornado watch issuance is likely prior to 23Z. DISCUSSION...An MCV is currently moving through the upper Mississippi Valley, with a weakening area of primarily stratiform rain noted across northeast IA into northern IL. In the wake of the MCV, clearing has been noted across central into southeast IA, with cumulus gradually increasing along an outflow/differential heating boundary from west-central IL into southeast IA. Lapse rates are generally weak across this region, but continued heating of a very moist low-level airmass will result in the development of moderate to locally strong buoyancy (MLCAPE of 1500-3000 J/kg) from southeast IA into northwest/central IL. Forcing for ascent will be somewhat nebulous in the wake of the leading MCV, but scattered thunderstorm development is eventually expected in the vicinity of the surface boundary and a weak surface low across central IA. Area VWPs and the 20Z ILX sounding depict sufficient deep-layer shear for organized convection, and initial development will include the potential for a few discrete supercells. Some increase in low-level flow/shear is expected with time into the evening, and a tornado threat will evolve with any supercell, particularly in the vicinity of the surface boundary which may move slowly northward over the next 2-3 hours. A strong tornado will be possible if any supercell can become sustained in the zone of enhanced low-level helicity near and just north of the boundary. Otherwise, locally severe wind gusts and marginally severe hail will be possible with any discrete convection. Most HREF members depict some sort of upscale growth this evening into portions of central IL, which would pose an increasing risk of more widespread damaging winds and potentially QLCS tornadoes. Tornado watch issuance by 23Z is likely in order to cover these threats, though earlier watch issuance is possible if deep convective initiation appears imminent. ..Dean/Grams.. 08/12/2019 ...Please see www.spc.noaa.gov for graphic product... ATTN...WFO...LOT...ILX...LSX...DVN...DMX... LAT...LON 42379296 42439155 42159002 41898892 41218858 40618863 40118904 39828997 40089166 40629222 40959326 41289324 42379296 Read more

MD 1716 CONCERNING SEVERE POTENTIAL...WATCH UNLIKELY FOR EASTERN TX PANHANDLE...NORTHWEST OK...FAR SOUTH-CENTRAL KS
Mesoscale Discussion 1716 NWS Storm Prediction Center Norman OK 0338 PM CDT Mon Aug 12 2019 Areas affected...eastern TX Panhandle...northwest OK...far south-central KS Concerning...Severe potential...Watch unlikely Valid 122038Z - 122145Z Probability of Watch Issuance...20 percent SUMMARY...Isolated severe gusts (60-70mph) are possible with the stronger storms through the early evening. The magnitude and coverage of the severe risk will likely preclude a severe thunderstorm watch issuance. DISCUSSION...Surface analysis shows temperatures have warmed into the lower 100s over the TX Panhandle northeastward into south-central KS. Strong boundary-layer mixing has resulted in surface temperature spreads around 40 deg F, and as a result, very steep low-level lapse rates have developed. Objective analysis indicates a belt of modest southwesterly mid- to high-level flow is located over the region to the northwest of the mid-level anticyclone centered over southeast TX. The strength of flow will result in some multicellular storm organization as storms move to the northeast. Strong to locally severe gusts/small hail may accompany the stronger cores. ..Smith/Grams.. 08/12/2019 ...Please see www.spc.noaa.gov for graphic product... ATTN...WFO...ICT...OUN...DDC...AMA... LAT...LON 35560130 36999907 37189710 36409785 35040047 35560130 Read more

SPC 2000Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0251 PM CDT Mon Aug 12 2019 Valid 122000Z - 131200Z ...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF THE UPPER MIDWEST INTO THE OHIO VALLEY... ...SUMMARY... A few tornadoes with a potential for a strong tornado and significant damaging winds will be possible across southeast Iowa through central Illinois, mainly this evening. ...DISCUSSION... The only change to the outlook is to add thunder across parts of the Colorado Rockies where a few thunderstorms are expected to develop this afternoon. ..Broyles.. 08/12/2019 .PREV DISCUSSION... /ISSUED 1130 AM CDT Mon Aug 12 2019/ ...IA/IL/IN... An upgrade to Moderate Risk for tornado and/or wind may become necessary in later outlooks today. A leading MCV is tracking east into eastern IA with a lingering surface cyclone centered over west-central IA. This latter feature should move east into northern IL through this evening. Diffuse convective outflow from remnant leading MCS over southern IL has been shunted across southeast to northwest MO. Nevertheless, air mass recovery is underway north of the boundary into extreme southern IA and west-central IL. Further erosion of the prior cold pool amid cloud breaks should yield at least weak to moderate surface-based buoyancy by late afternoon in IA to northern IL. More robust destabilization is expected farther south where greater unimpeded insolation occurs while a plume of 77-81 F surface dew points is advected north from the Mid-South. Despite relatively warm mid-level temperatures, the very rich boundary-layer moisture and surface heating should yield a plume of large buoyancy with MLCAPE likely reaching 3000-4000 J/kg across much of MO into central/southern IL. Renewed thunderstorm development is probable towards late afternoon near the surface cyclone in southeast IA and during the early evening to the southeast in central IL within a corridor of strengthening low-level warm advection. The initial storms will likely be supercells capable of producing all hazards, given the enhanced low-level shear/hodograph curvature near the cyclone/warm front. Hodographs aloft should tend to favor relatively quick upscale growth, but even semi-discrete supercells will pose a risk for at least a few tornadoes, a couple of which be may strong. A forward-propagating MCS should eventually evolve along the MLCAPE gradient from central IL into central IN where severe wind gusts will remain a threat before weakening overnight. ...TX Panhandle to southern KS/northern OK... A remnant midlevel trough will drift slowly east-northeastward over the TX Panhandle, as a weak cold front moves slowly southeastward from KS/CO. Surface heating and deep mixing will result in inverted-v profiles along and south of the front, and will support the potential for isolated strong downburst winds. Convection will tend to develop east-northeastward tonight along the front, with strong downdrafts still possible in an environment of lingering large CAPE/DCAPE. ...ME... A midlevel trough over James Bay will pivot east-southeastward to Maine overnight. In advance of this trough, a weak pre-frontal trough at the surface and band of weak ascent will provide a focus for thunderstorm development this afternoon. Though moisture and lapse rates will be modest, increasing deep-layer westerly shear and surface heating on the south edge of the thicker clouds could support storms capable of producing isolated damaging gusts and marginally severe hail. ...Dakotas... Widespread clouds and rain are spreading slowly eastward across the eastern Dakotas in association with a couple of diffuse MCVs from overnight convection. A little clearing of clouds and surface heating will be possible from west to east this afternoon, in advance of a larger-scale trough moving east-southeastward from MT to ND. Isolated thunderstorm development and a low-end severe threat will be possible this afternoon if sufficient near-surface destabilization occurs, given enough vertical shear for organized storms. Read more

SPC 2000Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0251 PM CDT Mon Aug 12 2019 Valid 122000Z - 131200Z ...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF THE UPPER MIDWEST INTO THE OHIO VALLEY... ...SUMMARY... A few tornadoes with a potential for a strong tornado and significant damaging winds will be possible across southeast Iowa through central Illinois, mainly this evening. ...DISCUSSION... The only change to the outlook is to add thunder across parts of the Colorado Rockies where a few thunderstorms are expected to develop this afternoon. ..Broyles.. 08/12/2019 .PREV DISCUSSION... /ISSUED 1130 AM CDT Mon Aug 12 2019/ ...IA/IL/IN... An upgrade to Moderate Risk for tornado and/or wind may become necessary in later outlooks today. A leading MCV is tracking east into eastern IA with a lingering surface cyclone centered over west-central IA. This latter feature should move east into northern IL through this evening. Diffuse convective outflow from remnant leading MCS over southern IL has been shunted across southeast to northwest MO. Nevertheless, air mass recovery is underway north of the boundary into extreme southern IA and west-central IL. Further erosion of the prior cold pool amid cloud breaks should yield at least weak to moderate surface-based buoyancy by late afternoon in IA to northern IL. More robust destabilization is expected farther south where greater unimpeded insolation occurs while a plume of 77-81 F surface dew points is advected north from the Mid-South. Despite relatively warm mid-level temperatures, the very rich boundary-layer moisture and surface heating should yield a plume of large buoyancy with MLCAPE likely reaching 3000-4000 J/kg across much of MO into central/southern IL. Renewed thunderstorm development is probable towards late afternoon near the surface cyclone in southeast IA and during the early evening to the southeast in central IL within a corridor of strengthening low-level warm advection. The initial storms will likely be supercells capable of producing all hazards, given the enhanced low-level shear/hodograph curvature near the cyclone/warm front. Hodographs aloft should tend to favor relatively quick upscale growth, but even semi-discrete supercells will pose a risk for at least a few tornadoes, a couple of which be may strong. A forward-propagating MCS should eventually evolve along the MLCAPE gradient from central IL into central IN where severe wind gusts will remain a threat before weakening overnight. ...TX Panhandle to southern KS/northern OK... A remnant midlevel trough will drift slowly east-northeastward over the TX Panhandle, as a weak cold front moves slowly southeastward from KS/CO. Surface heating and deep mixing will result in inverted-v profiles along and south of the front, and will support the potential for isolated strong downburst winds. Convection will tend to develop east-northeastward tonight along the front, with strong downdrafts still possible in an environment of lingering large CAPE/DCAPE. ...ME... A midlevel trough over James Bay will pivot east-southeastward to Maine overnight. In advance of this trough, a weak pre-frontal trough at the surface and band of weak ascent will provide a focus for thunderstorm development this afternoon. Though moisture and lapse rates will be modest, increasing deep-layer westerly shear and surface heating on the south edge of the thicker clouds could support storms capable of producing isolated damaging gusts and marginally severe hail. ...Dakotas... Widespread clouds and rain are spreading slowly eastward across the eastern Dakotas in association with a couple of diffuse MCVs from overnight convection. A little clearing of clouds and surface heating will be possible from west to east this afternoon, in advance of a larger-scale trough moving east-southeastward from MT to ND. Isolated thunderstorm development and a low-end severe threat will be possible this afternoon if sufficient near-surface destabilization occurs, given enough vertical shear for organized storms. Read more

SPC 2000Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0251 PM CDT Mon Aug 12 2019 Valid 122000Z - 131200Z ...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF THE UPPER MIDWEST INTO THE OHIO VALLEY... ...SUMMARY... A few tornadoes with a potential for a strong tornado and significant damaging winds will be possible across southeast Iowa through central Illinois, mainly this evening. ...DISCUSSION... The only change to the outlook is to add thunder across parts of the Colorado Rockies where a few thunderstorms are expected to develop this afternoon. ..Broyles.. 08/12/2019 .PREV DISCUSSION... /ISSUED 1130 AM CDT Mon Aug 12 2019/ ...IA/IL/IN... An upgrade to Moderate Risk for tornado and/or wind may become necessary in later outlooks today. A leading MCV is tracking east into eastern IA with a lingering surface cyclone centered over west-central IA. This latter feature should move east into northern IL through this evening. Diffuse convective outflow from remnant leading MCS over southern IL has been shunted across southeast to northwest MO. Nevertheless, air mass recovery is underway north of the boundary into extreme southern IA and west-central IL. Further erosion of the prior cold pool amid cloud breaks should yield at least weak to moderate surface-based buoyancy by late afternoon in IA to northern IL. More robust destabilization is expected farther south where greater unimpeded insolation occurs while a plume of 77-81 F surface dew points is advected north from the Mid-South. Despite relatively warm mid-level temperatures, the very rich boundary-layer moisture and surface heating should yield a plume of large buoyancy with MLCAPE likely reaching 3000-4000 J/kg across much of MO into central/southern IL. Renewed thunderstorm development is probable towards late afternoon near the surface cyclone in southeast IA and during the early evening to the southeast in central IL within a corridor of strengthening low-level warm advection. The initial storms will likely be supercells capable of producing all hazards, given the enhanced low-level shear/hodograph curvature near the cyclone/warm front. Hodographs aloft should tend to favor relatively quick upscale growth, but even semi-discrete supercells will pose a risk for at least a few tornadoes, a couple of which be may strong. A forward-propagating MCS should eventually evolve along the MLCAPE gradient from central IL into central IN where severe wind gusts will remain a threat before weakening overnight. ...TX Panhandle to southern KS/northern OK... A remnant midlevel trough will drift slowly east-northeastward over the TX Panhandle, as a weak cold front moves slowly southeastward from KS/CO. Surface heating and deep mixing will result in inverted-v profiles along and south of the front, and will support the potential for isolated strong downburst winds. Convection will tend to develop east-northeastward tonight along the front, with strong downdrafts still possible in an environment of lingering large CAPE/DCAPE. ...ME... A midlevel trough over James Bay will pivot east-southeastward to Maine overnight. In advance of this trough, a weak pre-frontal trough at the surface and band of weak ascent will provide a focus for thunderstorm development this afternoon. Though moisture and lapse rates will be modest, increasing deep-layer westerly shear and surface heating on the south edge of the thicker clouds could support storms capable of producing isolated damaging gusts and marginally severe hail. ...Dakotas... Widespread clouds and rain are spreading slowly eastward across the eastern Dakotas in association with a couple of diffuse MCVs from overnight convection. A little clearing of clouds and surface heating will be possible from west to east this afternoon, in advance of a larger-scale trough moving east-southeastward from MT to ND. Isolated thunderstorm development and a low-end severe threat will be possible this afternoon if sufficient near-surface destabilization occurs, given enough vertical shear for organized storms. Read more

MD 1715 CONCERNING SEVERE POTENTIAL...WATCH UNLIKELY FOR NORTHWEST INTO CENTRAL ND
Mesoscale Discussion 1715 NWS Storm Prediction Center Norman OK 0232 PM CDT Mon Aug 12 2019 Areas affected...northwest into central ND Concerning...Severe potential...Watch unlikely Valid 121932Z - 122100Z Probability of Watch Issuance...20 percent SUMMARY...A few stronger storms are possible this afternoon. A weak/brief tornado and large hail are the primary severe risks. DISCUSSION...Surface analysis indicates an occluded front oriented from southeast to northwest bisecting ND. Visible satellite imagery shows a cumulus field over western ND and stratus to the east of the boundary. Surface temperatures have warmed into the lower to middle 70s west and lower 60s east. The boundary is providing a focus both for storm development this afternoon and a source for ambient vorticity rich low-level air. As storms increase both in number and intensity later this afternoon, a few may acquire weak/transient low-level rotation as they move east-southeast and interact with the zone of low-level vorticity along the boundary. A tornado is possible along with hail. The spatial coverage and intensity of the expected severe risk will likely preclude a severe thunderstorm watch issuance. ..Smith/Grams.. 08/12/2019 ...Please see www.spc.noaa.gov for graphic product... ATTN...WFO...BIS... LAT...LON 48490307 47840202 47290072 47350003 48000038 48820244 48490307 Read more

SPC Day 2 Fire Weather Outlook
Day 2 Fire Weather Outlook NWS Storm Prediction Center Norman OK 0155 PM CDT Mon Aug 12 2019 Valid 131200Z - 141200Z ...NO CRITICAL AREAS... The previous forecast remains on track, with no changes made. Please see below for more details. ..Squitieri.. 08/12/2019 .PREV DISCUSSION... /ISSUED 0712 AM CDT Mon Aug 12 2019/ ...Synopsis... Weak, quasi-zonal mid-level flow will continue across the northern tier of the CONUS D2/Tuesday. Flow at the surface and aloft will be minimal across dry areas of the West outside of localized, terrain-favored areas. With the lack of major synoptic features traversing the West, fire weather conditions will be minimal. No highlights will be introduced for this outlook. ...Please see www.spc.noaa.gov/fire for graphic product... Read more

SPC Day 2 Fire Weather Outlook
Day 2 Fire Weather Outlook NWS Storm Prediction Center Norman OK 0155 PM CDT Mon Aug 12 2019 Valid 131200Z - 141200Z ...NO CRITICAL AREAS... The previous forecast remains on track, with no changes made. Please see below for more details. ..Squitieri.. 08/12/2019 .PREV DISCUSSION... /ISSUED 0712 AM CDT Mon Aug 12 2019/ ...Synopsis... Weak, quasi-zonal mid-level flow will continue across the northern tier of the CONUS D2/Tuesday. Flow at the surface and aloft will be minimal across dry areas of the West outside of localized, terrain-favored areas. With the lack of major synoptic features traversing the West, fire weather conditions will be minimal. No highlights will be introduced for this outlook. ...Please see www.spc.noaa.gov/fire for graphic product... Read more

SPC Day 2 Fire Weather Outlook
Day 2 Fire Weather Outlook NWS Storm Prediction Center Norman OK 0155 PM CDT Mon Aug 12 2019 Valid 131200Z - 141200Z ...NO CRITICAL AREAS... The previous forecast remains on track, with no changes made. Please see below for more details. ..Squitieri.. 08/12/2019 .PREV DISCUSSION... /ISSUED 0712 AM CDT Mon Aug 12 2019/ ...Synopsis... Weak, quasi-zonal mid-level flow will continue across the northern tier of the CONUS D2/Tuesday. Flow at the surface and aloft will be minimal across dry areas of the West outside of localized, terrain-favored areas. With the lack of major synoptic features traversing the West, fire weather conditions will be minimal. No highlights will be introduced for this outlook. ...Please see www.spc.noaa.gov/fire for graphic product... Read more

SPC Day 2 Fire Weather Outlook
Day 2 Fire Weather Outlook NWS Storm Prediction Center Norman OK 0155 PM CDT Mon Aug 12 2019 Valid 131200Z - 141200Z ...NO CRITICAL AREAS... The previous forecast remains on track, with no changes made. Please see below for more details. ..Squitieri.. 08/12/2019 .PREV DISCUSSION... /ISSUED 0712 AM CDT Mon Aug 12 2019/ ...Synopsis... Weak, quasi-zonal mid-level flow will continue across the northern tier of the CONUS D2/Tuesday. Flow at the surface and aloft will be minimal across dry areas of the West outside of localized, terrain-favored areas. With the lack of major synoptic features traversing the West, fire weather conditions will be minimal. No highlights will be introduced for this outlook. ...Please see www.spc.noaa.gov/fire for graphic product... Read more

This fire is contained. It burned high desert grasses, brush and juniper about 10 miles east of the community of Madeline in Lassen County. This is the final update for this

MD 1714 CONCERNING SEVERE POTENTIAL...WATCH UNLIKELY FOR CENTRAL/SOUTHERN ME
Mesoscale Discussion 1714 NWS Storm Prediction Center Norman OK 0106 PM CDT Mon Aug 12 2019 Areas affected...Central/southern ME Concerning...Severe potential...Watch unlikely Valid 121806Z - 122030Z Probability of Watch Issuance...5 percent SUMMARY...Storms capable of locally damaging wind and marginally severe hail are possible this afternoon. Watch issuance is not anticipated. DISCUSSION...Despite widespread cloudiness, gradual heating is underway across much of Maine, with an increase in cumulus noted within the last hour. While large-scale ascent will generally be limited across the region this afternoon, widely scattered thunderstorm development will be possible as a weak surface trough and midlevel speed max approach the area from the west. Midlevel lapse rates are rather weak, but continued heating and sufficient moisture will result in MLCAPE of 500-1000 J/kg across portions of ME later this afternoon. Moderate southwesterly aloft will support effective shear of 30-40 kt, sufficient for some storm organization with the strongest updrafts. The most favorable overlap of shear and buoyancy is forecast over the central third of Maine. Marginally severe hail will be possible with the most organized cells, while locally damaging wind cannot be ruled out, especially in areas where greater heating occurs resulting in steeper low-level lapse rates. Due to the marginality of the threat, watch issuance is not expected. ..Dean/Grams.. 08/12/2019 ...Please see www.spc.noaa.gov for graphic product... ATTN...WFO...CAR...GYX... LAT...LON 44586733 44676880 44656948 44617042 44707093 45047094 45287091 45717059 45967017 46036879 46016820 45936776 45876745 45056693 44586733 Read more

000
ABNT20 KNHC 121745
TWOAT

Tropical Weather Outlook
NWS National Hurricane Center Miami FL
200 PM EDT Mon Aug 12 2019

For the North Atlantic...Caribbean Sea and the Gulf of Mexico:

Tropical cyclone formation is not expected during the next 5 days.

$$
Forecaster Latto/Pasch

000
ABPZ20 KNHC 121744
TWOEP

Tropical Weather Outlook
NWS National Hurricane Center Miami FL
1100 AM PDT Mon Aug 12 2019

For the eastern North Pacific...east of 140 degrees west longitude:

The National Hurricane Center is issuing advisories on Tropical
Storm Henriette, located a few hundred miles southwest of the
southern tip of the Baja California peninsula.

Disorganized showers and thunderstorms located just over 1000 miles
southwest of the southern tip of the Baja California peninsula are
associated with a trough of low pressure. Environmental conditions
are forecast to be conducive for some development during the next
few days, and a tropical depression could form later this week while
the system moves west-northwestward at around 15 mph.
* Formation chance through 48 hours...low...30 percent.
* Formation chance through 5 days...medium...60 percent.

&&
Public Advisories on Tropical Storm Henriette are issued under
WMO header WTPZ34 KNHC and under AWIPS header MIATCPEP4.
Forecast/Advisories on Tropical Storm Henriette are issued
under WMO header WTPZ24 KNHC and under AWIPS header MIATCMEP4.

$$
Forecaster Latto/Pasch

SPC 1730Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1219 PM CDT Mon Aug 12 2019 Valid 131200Z - 141200Z ...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF THE CENTRAL APPALACHIANS EASTWARD TO THE MID-ATLANTIC... ...SUMMARY... Severe storms are expected Tuesday afternoon and early evening over the Middle Atlantic into the Ohio and Tennessee Valleys. Other strong to severe storms are possible over the Upper Mississippi Valley and the central High Plains. ...Mid-Atlantic/Ohio and Tennessee Valleys... A subtle cyclonic mid-level flow pattern will be in place on Tuesday from the north-central states eastward into the Northeast. At the surface, a cold front will advance southward into the Mid-Atlantic extending west-southwestward into the mid Mississippi Valley. A surface low along the front will move eastward across the central Appalachians. Surface dewpoints ahead of the front should be in the lower 70s contributing to a corridor of moderate instability by afternoon. Scattered thunderstorms are forecast to develop along the front during the afternoon from southern Ohio eastward across the Virginias into Maryland. Cells may tend to organize into lines and MCS development will be possible from late afternoon into the early evening. NAM forecast soundings along the front from West Virginia into northern Virginia and southern Maryland suggest that MLCAPE values could reach 2500 J/kg at peak heating. Winds are veered to the southwest at the surface with about 30 kt of westerly flow in the mid-levels. This combined with steep lapse rates in the lowest 3 km AGL will be favorable for damaging wind gusts associated with line segments. If a cold pool can develop with a larger-scale line segment, then numerous damaging wind gusts will be possible from eastern West Virginia eastward to Delaware and southern New Jersey. ...Upper Mississippi Valley... A minor shortwave trough will move east-southeastward into the Upper Mississippi Valley on Tuesday. At the surface, a low will track southeastward from central Minnesota to near Minneapolis and then along the Mississippi River. Ahead of the surface low track, an axis of maximized low-level moisture will exist with surface dewpoints in the mid 60s F. In response to surface heating, a pocket of moderate instability may develop by afternoon. Convection is forecast to initiate ahead of the shortwave trough and move southeastward across eastern Minnesota and western Wisconsin during the mid to late afternoon. MLCAPE values in the 1000 to 2000 J/kg combined with 0-6 km shear of 35 to 45 kt may be favorable for an isolated severe threat with hail and strong gusty winds possible. Poor lapse rates should keep any threat marginal. ...Central Plains... A low-amplitude upper-level ridge will move across the western U.S. on Tuesday as west to northwest mid-level flow remains over the central High Plains. At the surface, a mesolow is forecast to develop in southeastern Colorado ahead of a front, moving southward into northeastern Colorado. Convection appears likely to initiate along the front during the late afternoon with thunderstorms moving southeastward into western Kansas by early evening. Strong directional shear profiles along with steep lapse rates may be enough for hail in the stronger cores. A few marginally severe wind gusts will also be possible. ...MAXIMUM RISK BY HAZARD... Tornado: 5% - Slight Wind: 30% - Enhanced Hail: 15% - Slight ..Broyles.. 08/12/2019 Read more

SPC 1730Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1219 PM CDT Mon Aug 12 2019 Valid 131200Z - 141200Z ...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF THE CENTRAL APPALACHIANS EASTWARD TO THE MID-ATLANTIC... ...SUMMARY... Severe storms are expected Tuesday afternoon and early evening over the Middle Atlantic into the Ohio and Tennessee Valleys. Other strong to severe storms are possible over the Upper Mississippi Valley and the central High Plains. ...Mid-Atlantic/Ohio and Tennessee Valleys... A subtle cyclonic mid-level flow pattern will be in place on Tuesday from the north-central states eastward into the Northeast. At the surface, a cold front will advance southward into the Mid-Atlantic extending west-southwestward into the mid Mississippi Valley. A surface low along the front will move eastward across the central Appalachians. Surface dewpoints ahead of the front should be in the lower 70s contributing to a corridor of moderate instability by afternoon. Scattered thunderstorms are forecast to develop along the front during the afternoon from southern Ohio eastward across the Virginias into Maryland. Cells may tend to organize into lines and MCS development will be possible from late afternoon into the early evening. NAM forecast soundings along the front from West Virginia into northern Virginia and southern Maryland suggest that MLCAPE values could reach 2500 J/kg at peak heating. Winds are veered to the southwest at the surface with about 30 kt of westerly flow in the mid-levels. This combined with steep lapse rates in the lowest 3 km AGL will be favorable for damaging wind gusts associated with line segments. If a cold pool can develop with a larger-scale line segment, then numerous damaging wind gusts will be possible from eastern West Virginia eastward to Delaware and southern New Jersey. ...Upper Mississippi Valley... A minor shortwave trough will move east-southeastward into the Upper Mississippi Valley on Tuesday. At the surface, a low will track southeastward from central Minnesota to near Minneapolis and then along the Mississippi River. Ahead of the surface low track, an axis of maximized low-level moisture will exist with surface dewpoints in the mid 60s F. In response to surface heating, a pocket of moderate instability may develop by afternoon. Convection is forecast to initiate ahead of the shortwave trough and move southeastward across eastern Minnesota and western Wisconsin during the mid to late afternoon. MLCAPE values in the 1000 to 2000 J/kg combined with 0-6 km shear of 35 to 45 kt may be favorable for an isolated severe threat with hail and strong gusty winds possible. Poor lapse rates should keep any threat marginal. ...Central Plains... A low-amplitude upper-level ridge will move across the western U.S. on Tuesday as west to northwest mid-level flow remains over the central High Plains. At the surface, a mesolow is forecast to develop in southeastern Colorado ahead of a front, moving southward into northeastern Colorado. Convection appears likely to initiate along the front during the late afternoon with thunderstorms moving southeastward into western Kansas by early evening. Strong directional shear profiles along with steep lapse rates may be enough for hail in the stronger cores. A few marginally severe wind gusts will also be possible. ...MAXIMUM RISK BY HAZARD... Tornado: 5% - Slight Wind: 30% - Enhanced Hail: 15% - Slight ..Broyles.. 08/12/2019 Read more

SPC 1730Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1219 PM CDT Mon Aug 12 2019 Valid 131200Z - 141200Z ...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF THE CENTRAL APPALACHIANS EASTWARD TO THE MID-ATLANTIC... ...SUMMARY... Severe storms are expected Tuesday afternoon and early evening over the Middle Atlantic into the Ohio and Tennessee Valleys. Other strong to severe storms are possible over the Upper Mississippi Valley and the central High Plains. ...Mid-Atlantic/Ohio and Tennessee Valleys... A subtle cyclonic mid-level flow pattern will be in place on Tuesday from the north-central states eastward into the Northeast. At the surface, a cold front will advance southward into the Mid-Atlantic extending west-southwestward into the mid Mississippi Valley. A surface low along the front will move eastward across the central Appalachians. Surface dewpoints ahead of the front should be in the lower 70s contributing to a corridor of moderate instability by afternoon. Scattered thunderstorms are forecast to develop along the front during the afternoon from southern Ohio eastward across the Virginias into Maryland. Cells may tend to organize into lines and MCS development will be possible from late afternoon into the early evening. NAM forecast soundings along the front from West Virginia into northern Virginia and southern Maryland suggest that MLCAPE values could reach 2500 J/kg at peak heating. Winds are veered to the southwest at the surface with about 30 kt of westerly flow in the mid-levels. This combined with steep lapse rates in the lowest 3 km AGL will be favorable for damaging wind gusts associated with line segments. If a cold pool can develop with a larger-scale line segment, then numerous damaging wind gusts will be possible from eastern West Virginia eastward to Delaware and southern New Jersey. ...Upper Mississippi Valley... A minor shortwave trough will move east-southeastward into the Upper Mississippi Valley on Tuesday. At the surface, a low will track southeastward from central Minnesota to near Minneapolis and then along the Mississippi River. Ahead of the surface low track, an axis of maximized low-level moisture will exist with surface dewpoints in the mid 60s F. In response to surface heating, a pocket of moderate instability may develop by afternoon. Convection is forecast to initiate ahead of the shortwave trough and move southeastward across eastern Minnesota and western Wisconsin during the mid to late afternoon. MLCAPE values in the 1000 to 2000 J/kg combined with 0-6 km shear of 35 to 45 kt may be favorable for an isolated severe threat with hail and strong gusty winds possible. Poor lapse rates should keep any threat marginal. ...Central Plains... A low-amplitude upper-level ridge will move across the western U.S. on Tuesday as west to northwest mid-level flow remains over the central High Plains. At the surface, a mesolow is forecast to develop in southeastern Colorado ahead of a front, moving southward into northeastern Colorado. Convection appears likely to initiate along the front during the late afternoon with thunderstorms moving southeastward into western Kansas by early evening. Strong directional shear profiles along with steep lapse rates may be enough for hail in the stronger cores. A few marginally severe wind gusts will also be possible. ...MAXIMUM RISK BY HAZARD... Tornado: 5% - Slight Wind: 30% - Enhanced Hail: 15% - Slight ..Broyles.. 08/12/2019 Read more

SPC 1730Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1219 PM CDT Mon Aug 12 2019 Valid 131200Z - 141200Z ...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF THE CENTRAL APPALACHIANS EASTWARD TO THE MID-ATLANTIC... ...SUMMARY... Severe storms are expected Tuesday afternoon and early evening over the Middle Atlantic into the Ohio and Tennessee Valleys. Other strong to severe storms are possible over the Upper Mississippi Valley and the central High Plains. ...Mid-Atlantic/Ohio and Tennessee Valleys... A subtle cyclonic mid-level flow pattern will be in place on Tuesday from the north-central states eastward into the Northeast. At the surface, a cold front will advance southward into the Mid-Atlantic extending west-southwestward into the mid Mississippi Valley. A surface low along the front will move eastward across the central Appalachians. Surface dewpoints ahead of the front should be in the lower 70s contributing to a corridor of moderate instability by afternoon. Scattered thunderstorms are forecast to develop along the front during the afternoon from southern Ohio eastward across the Virginias into Maryland. Cells may tend to organize into lines and MCS development will be possible from late afternoon into the early evening. NAM forecast soundings along the front from West Virginia into northern Virginia and southern Maryland suggest that MLCAPE values could reach 2500 J/kg at peak heating. Winds are veered to the southwest at the surface with about 30 kt of westerly flow in the mid-levels. This combined with steep lapse rates in the lowest 3 km AGL will be favorable for damaging wind gusts associated with line segments. If a cold pool can develop with a larger-scale line segment, then numerous damaging wind gusts will be possible from eastern West Virginia eastward to Delaware and southern New Jersey. ...Upper Mississippi Valley... A minor shortwave trough will move east-southeastward into the Upper Mississippi Valley on Tuesday. At the surface, a low will track southeastward from central Minnesota to near Minneapolis and then along the Mississippi River. Ahead of the surface low track, an axis of maximized low-level moisture will exist with surface dewpoints in the mid 60s F. In response to surface heating, a pocket of moderate instability may develop by afternoon. Convection is forecast to initiate ahead of the shortwave trough and move southeastward across eastern Minnesota and western Wisconsin during the mid to late afternoon. MLCAPE values in the 1000 to 2000 J/kg combined with 0-6 km shear of 35 to 45 kt may be favorable for an isolated severe threat with hail and strong gusty winds possible. Poor lapse rates should keep any threat marginal. ...Central Plains... A low-amplitude upper-level ridge will move across the western U.S. on Tuesday as west to northwest mid-level flow remains over the central High Plains. At the surface, a mesolow is forecast to develop in southeastern Colorado ahead of a front, moving southward into northeastern Colorado. Convection appears likely to initiate along the front during the late afternoon with thunderstorms moving southeastward into western Kansas by early evening. Strong directional shear profiles along with steep lapse rates may be enough for hail in the stronger cores. A few marginally severe wind gusts will also be possible. ...MAXIMUM RISK BY HAZARD... Tornado: 5% - Slight Wind: 30% - Enhanced Hail: 15% - Slight ..Broyles.. 08/12/2019 Read more

SPC 1630Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1130 AM CDT Mon Aug 12 2019 Valid 121630Z - 131200Z ...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS SOUTHEAST IA TO WEST-CENTRAL IN... ...SUMMARY... A few tornadoes, a couple possibly strong, and significant damaging winds will be likely across southeast Iowa through central Illinois, mainly this evening. ...IA/IL/IN... An upgrade to Moderate Risk for tornado and/or wind may become necessary in later outlooks today. A leading MCV is tracking east into eastern IA with a lingering surface cyclone centered over west-central IA. This latter feature should move east into northern IL through this evening. Diffuse convective outflow from remnant leading MCS over southern IL has been shunted across southeast to northwest MO. Nevertheless, air mass recovery is underway north of the boundary into extreme southern IA and west-central IL. Further erosion of the prior cold pool amid cloud breaks should yield at least weak to moderate surface-based buoyancy by late afternoon in IA to northern IL. More robust destabilization is expected farther south where greater unimpeded insolation occurs while a plume of 77-81 F surface dew points is advected north from the Mid-South. Despite relatively warm mid-level temperatures, the very rich boundary-layer moisture and surface heating should yield a plume of large buoyancy with MLCAPE likely reaching 3000-4000 J/kg across much of MO into central/southern IL. Renewed thunderstorm development is probable towards late afternoon near the surface cyclone in southeast IA and during the early evening to the southeast in central IL within a corridor of strengthening low-level warm advection. The initial storms will likely be supercells capable of producing all hazards, given the enhanced low-level shear/hodograph curvature near the cyclone/warm front. Hodographs aloft should tend to favor relatively quick upscale growth, but even semi-discrete supercells will pose a risk for at least a few tornadoes, a couple of which be may strong. A forward-propagating MCS should eventually evolve along the MLCAPE gradient from central IL into central IN where severe wind gusts will remain a threat before weakening overnight. ...TX Panhandle to southern KS/northern OK... A remnant midlevel trough will drift slowly east-northeastward over the TX Panhandle, as a weak cold front moves slowly southeastward from KS/CO. Surface heating and deep mixing will result in inverted-v profiles along and south of the front, and will support the potential for isolated strong downburst winds. Convection will tend to develop east-northeastward tonight along the front, with strong downdrafts still possible in an environment of lingering large CAPE/DCAPE. ...ME... A midlevel trough over James Bay will pivot east-southeastward to Maine overnight. In advance of this trough, a weak pre-frontal trough at the surface and band of weak ascent will provide a focus for thunderstorm development this afternoon. Though moisture and lapse rates will be modest, increasing deep-layer westerly shear and surface heating on the south edge of the thicker clouds could support storms capable of producing isolated damaging gusts and marginally severe hail. ...Dakotas... Widespread clouds and rain are spreading slowly eastward across the eastern Dakotas in association with a couple of diffuse MCVs from overnight convection. A little clearing of clouds and surface heating will be possible from west to east this afternoon, in advance of a larger-scale trough moving east-southeastward from MT to ND. Isolated thunderstorm development and a low-end severe threat will be possible this afternoon if sufficient near-surface destabilization occurs, given enough vertical shear for organized storms. ..Grams/Dean.. 08/12/2019 Read more