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Day 4-8 Outlook
Day 4-8 Convective Outlook NWS Storm Prediction Center Norman OK 0358 AM CDT Fri Sep 27 2019 Valid 301200Z - 051200Z ...DISCUSSION... Upper troughing over the western CONUS should acquire a positive tilt on Day 4/Monday as an upper ridge remains across the southern Plains, much of the lower/mid MS Valley, OH Valley, and Southeast. As a surface low develops northeastward across the Upper Midwest, a cold front should progress slowly southeastward. An inversion may tend to limit convective coverage through the day. Lift via warm air advection from a strengthening low-level jet Monday evening will probably be needed to overcome the cap, with storms becoming more likely late Monday into early Tuesday along the front from the central Plains into parts of the Upper Midwest. Although shear will remain strong across this region, it is forecast to be largely parallel to the surface boundary. This suggests storms may be undercut by the front as it moves slowly southeastward. For now, the overall severe threat for Day 4/Monday appears too marginal to include 15% severe probabilities. A broad mid/upper-level jet should extend from the Great Basin across the central Rockies and into the Upper Midwest on Day 5/Tuesday. A surface front draped from the Great Lakes southwestward into the central Plains should make little southward progress through the day as southwesterly flow prevails aloft. A marginal severe risk may be present along portions of the front Tuesday afternoon, but storms will probably be undercut and become elevated with time. There also appears to be some severe potential across parts of the Northeast as a warm front lifts northward across this area and low-level moisture increases. This potential appears too uncertain to include any severe probabilities at this time. Confidence in the synoptic-scale pattern decreases rapidly from Day 6/Wednesday onward, as medium-range guidance solutions begin to diverge regarding the evolution of another large-scale upper trough over the western CONUS. A severe threat may eventually materialize late next week across some part of the Plains if this upper trough ejects eastward. But, details are highly uncertain at this extended time frame. Read more

Day 4-8 Outlook
Day 4-8 Convective Outlook NWS Storm Prediction Center Norman OK 0358 AM CDT Fri Sep 27 2019 Valid 301200Z - 051200Z ...DISCUSSION... Upper troughing over the western CONUS should acquire a positive tilt on Day 4/Monday as an upper ridge remains across the southern Plains, much of the lower/mid MS Valley, OH Valley, and Southeast. As a surface low develops northeastward across the Upper Midwest, a cold front should progress slowly southeastward. An inversion may tend to limit convective coverage through the day. Lift via warm air advection from a strengthening low-level jet Monday evening will probably be needed to overcome the cap, with storms becoming more likely late Monday into early Tuesday along the front from the central Plains into parts of the Upper Midwest. Although shear will remain strong across this region, it is forecast to be largely parallel to the surface boundary. This suggests storms may be undercut by the front as it moves slowly southeastward. For now, the overall severe threat for Day 4/Monday appears too marginal to include 15% severe probabilities. A broad mid/upper-level jet should extend from the Great Basin across the central Rockies and into the Upper Midwest on Day 5/Tuesday. A surface front draped from the Great Lakes southwestward into the central Plains should make little southward progress through the day as southwesterly flow prevails aloft. A marginal severe risk may be present along portions of the front Tuesday afternoon, but storms will probably be undercut and become elevated with time. There also appears to be some severe potential across parts of the Northeast as a warm front lifts northward across this area and low-level moisture increases. This potential appears too uncertain to include any severe probabilities at this time. Confidence in the synoptic-scale pattern decreases rapidly from Day 6/Wednesday onward, as medium-range guidance solutions begin to diverge regarding the evolution of another large-scale upper trough over the western CONUS. A severe threat may eventually materialize late next week across some part of the Plains if this upper trough ejects eastward. But, details are highly uncertain at this extended time frame. Read more

5-Day Uncertainty Track last updated Fri, 27 Sep 2019 09:00:54 GMT


Wind Speed Probabilities last updated Fri, 27 Sep 2019 09:31:19 GMT

Issued at 500 AM AST Fri Sep 27 2019 000 WTNT43 KNHC 270858 TCDAT3 Hurricane Lorenzo Discussion Number 19 NWS National Hurricane Center Miami FL AL132019 500 AM AST Fri Sep 27 2019 Lorenzo has maintained its impressive structure in satellite imagery this morning. The hurricane still has a fairly clear eye surrounded by very cold cloud tops. A 0423 UTC AMSR2 overpass showed a small break in the deepest convection in the southwest eyewall of the hurricane, but given how cloud tops have cooled since then, I suspect that did not last long. Satellite intensity estimates have not changed substantially since the last advisory, so the initial intensity remains 125 kt. The hurricane is moving steadily north-northwestward at 12 kt. The track guidance is in remarkably good agreement on Lorenzo's track and confidence in the forecast is high. Lorenzo should turn northward and then northeastward during the next few days as it moves around the western edge of a mid-level ridge centered over the eastern Atlantic. By the end of the forecast period, Lorenzo will likely accelerate northeastward ahead of mid-latitude trough approaching from the west. The official track forecast is basically unchanged since the last advisory and now sits right in the middle of the guidance envelope. The NHC intensity forecast is also mostly unchanged since the last advisory. Although SHIPS diagnostics suggest that moderate southwesterly shear could soon affect the cyclone, not much change in strength is anticipated for the next 24 hours since Lorenzo will be moving over slightly warmer waters and an eyewall replacement cycle does not seem imminent. Gradual weakening is then anticipated through early next week due to a modest increase in shear and a decrease in available ocean heat content. Short-term fluctuations in intensity related to eyewall replacement cycles are also possible during that time. The NHC forecast remains on the high side of the guidance for the first 24 hours, and is close to HCCA after that. FORECAST POSITIONS AND MAX WINDS INIT 27/0900Z 18.6N 42.1W 125 KT 145 MPH 12H 27/1800Z 20.1N 42.9W 125 KT 145 MPH 24H 28/0600Z 21.8N 43.5W 120 KT 140 MPH 36H 28/1800Z 23.5N 43.8W 115 KT 130 MPH 48H 29/0600Z 25.1N 43.4W 110 KT 125 MPH 72H 30/0600Z 28.7N 41.4W 100 KT 115 MPH 96H 01/0600Z 33.3N 37.7W 95 KT 110 MPH 120H 02/0600Z 40.0N 30.5W 85 KT 100 MPH $$ Forecaster Zelinsky

Issued at 0900 UTC FRI SEP 27 2019 000 FONT13 KNHC 270855 PWSAT3 HURRICANE LORENZO WIND SPEED PROBABILITIES NUMBER 19 NWS NATIONAL HURRICANE CENTER MIAMI FL AL132019 0900 UTC FRI SEP 27 2019 AT 0900Z THE CENTER OF HURRICANE LORENZO WAS LOCATED NEAR LATITUDE 18.6 NORTH...LONGITUDE 42.1 WEST WITH MAXIMUM SUSTAINED WINDS NEAR 125 KTS...145 MPH...230 KM/H. Z INDICATES COORDINATED UNIVERSAL TIME (GREENWICH) ATLANTIC STANDARD TIME (AST)...SUBTRACT 4 HOURS FROM Z TIME EASTERN DAYLIGHT TIME (EDT)...SUBTRACT 4 HOURS FROM Z TIME CENTRAL DAYLIGHT TIME (CDT)...SUBTRACT 5 HOURS FROM Z TIME WIND SPEED PROBABILITY TABLE FOR SPECIFIC LOCATIONS CHANCES OF SUSTAINED (1-MINUTE AVERAGE) WIND SPEEDS OF AT LEAST ...34 KT (39 MPH... 63 KM/H)... ...50 KT (58 MPH... 93 KM/H)... ...64 KT (74 MPH...119 KM/H)... FOR LOCATIONS AND TIME PERIODS DURING THE NEXT 5 DAYS PROBABILITIES FOR LOCATIONS ARE GIVEN AS OP(CP) WHERE OP IS THE PROBABILITY OF THE EVENT BEGINNING DURING AN INDIVIDUAL TIME PERIOD (ONSET PROBABILITY) (CP) IS THE PROBABILITY OF THE EVENT OCCURRING BETWEEN 06Z FRI AND THE FORECAST HOUR (CUMULATIVE PROBABILITY) PROBABILITIES ARE GIVEN IN PERCENT X INDICATES PROBABILITIES LESS THAN 1 PERCENT PROBABILITIES FOR 34 KT AND 50 KT ARE SHOWN AT A GIVEN LOCATION WHEN THE 5-DAY CUMULATIVE PROBABILITY IS AT LEAST 3 PERCENT. PROBABILITIES FOR 34...50...64 KT SHOWN WHEN THE 5-DAY 64-KT CUMULATIVE PROBABILITY IS AT LEAST 1 PERCENT. - - - - WIND SPEED PROBABILITIES FOR SELECTED LOCATIONS - - - - FROM FROM FROM FROM FROM FROM FROM TIME 06Z FRI 18Z FRI 06Z SAT 18Z SAT 06Z SUN 06Z MON 06Z TUE PERIODS TO TO TO TO TO TO TO 18Z FRI 06Z SAT 18Z SAT 06Z SUN 06Z MON 06Z TUE 06Z WED FORECAST HOUR (12) (24) (36) (48) (72) (96) (120) - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - LOCATION KT SANTA CRUZ AZO 34 X X( X) X( X) X( X) X( X) X( X) 76(76) SANTA CRUZ AZO 50 X X( X) X( X) X( X) X( X) X( X) 45(45) SANTA CRUZ AZO 64 X X( X) X( X) X( X) X( X) X( X) 24(24) PONTA DELGADA 34 X X( X) X( X) X( X) X( X) X( X) 17(17) $$ FORECASTER ZELINSKY

Issued at 500 AM AST Fri Sep 27 2019 000 WTNT33 KNHC 270855 TCPAT3 BULLETIN Hurricane Lorenzo Advisory Number 19 NWS National Hurricane Center Miami FL AL132019 500 AM AST Fri Sep 27 2019 ...POWERFUL LORENZO MAINTAINING STRENGTH... SUMMARY OF 500 AM AST...0900 UTC...INFORMATION ---------------------------------------------- LOCATION...18.6N 42.1W ABOUT 1620 MI...2605 KM SW OF THE AZORES MAXIMUM SUSTAINED WINDS...145 MPH...230 KM/H PRESENT MOVEMENT...NNW OR 330 DEGREES AT 14 MPH...22 KM/H MINIMUM CENTRAL PRESSURE...937 MB...27.67 INCHES WATCHES AND WARNINGS -------------------- There are no coastal watches or warnings in effect. DISCUSSION AND OUTLOOK ---------------------- At 500 AM AST (0900 UTC), the center of Hurricane Lorenzo was located near latitude 18.6 North, longitude 42.1 West. Lorenzo is moving toward the north-northwest near 14 mph (22 km/h), and this general motion is forecast to continue today. A turn toward the north is expected on Saturday, followed by a turn toward the northeast on Sunday. Maximum sustained winds remain near 145 mph (230 km/h) with higher gusts. Lorenzo is a category 4 hurricane on the Saffir-Simpson Hurricane Wind Scale. Some fluctuations in strength are possible today. Slow weakening is forecast to begin by the weekend. Lorenzo is a large hurricane. Hurricane-force winds extend outward up to 45 miles (75 km) from the center and tropical-storm-force winds extend outward up to 265 miles (425 km). The estimated minimum central pressure is 937 mb (27.67 inches). HAZARDS AFFECTING LAND ---------------------- SURF: Swells generated by Lorenzo are affecting portions of the northeastern coast of South America and will affect portions of the Windward Islands beginning today. These swells are likely to cause life-threatening surf and rip current conditions. Please consult products from your local weather office. NEXT ADVISORY ------------- Next complete advisory at 1100 AM AST. $$ Forecaster Zelinsky

...POWERFUL LORENZO MAINTAINING STRENGTH... As of 5:00 AM AST Fri Sep 27 the center of Lorenzo was located near 18.6, -42.1 with movement NNW at 14 mph. The minimum central pressure was 937 mb with maximum sustained winds of about 145 mph.

5-Day Uncertainty Track last updated Fri, 27 Sep 2019 08:51:39 GMT


Wind Speed Probabilities last updated Fri, 27 Sep 2019 09:24:26 GMT

Issued at 0900 UTC FRI SEP 27 2019 982 WTNT23 KNHC 270850 TCMAT3 HURRICANE LORENZO FORECAST/ADVISORY NUMBER 19 NWS NATIONAL HURRICANE CENTER MIAMI FL AL132019 0900 UTC FRI SEP 27 2019 THERE ARE NO COASTAL WATCHES OR WARNINGS IN EFFECT. HURRICANE CENTER LOCATED NEAR 18.6N 42.1W AT 27/0900Z POSITION ACCURATE WITHIN 15 NM PRESENT MOVEMENT TOWARD THE NORTH-NORTHWEST OR 330 DEGREES AT 12 KT ESTIMATED MINIMUM CENTRAL PRESSURE 937 MB EYE DIAMETER 20 NM MAX SUSTAINED WINDS 125 KT WITH GUSTS TO 150 KT. 64 KT....... 40NE 30SE 25SW 40NW. 50 KT.......150NE 130SE 50SW 100NW. 34 KT.......230NE 190SE 100SW 200NW. 12 FT SEAS..360NE 360SE 360SW 360NW. 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 18.6N 42.1W AT 27/0900Z AT 27/0600Z CENTER WAS LOCATED NEAR 18.1N 41.8W FORECAST VALID 27/1800Z 20.1N 42.9W MAX WIND 125 KT...GUSTS 150 KT. 64 KT... 40NE 30SE 25SW 40NW. 50 KT...150NE 130SE 50SW 100NW. 34 KT...230NE 190SE 100SW 200NW. FORECAST VALID 28/0600Z 21.8N 43.5W MAX WIND 120 KT...GUSTS 145 KT. 64 KT... 50NE 40SE 30SW 50NW. 50 KT...130NE 120SE 60SW 90NW. 34 KT...230NE 190SE 100SW 200NW. FORECAST VALID 28/1800Z 23.5N 43.8W MAX WIND 115 KT...GUSTS 140 KT. 64 KT... 50NE 40SE 30SW 50NW. 50 KT...120NE 100SE 60SW 90NW. 34 KT...200NE 180SE 110SW 160NW. FORECAST VALID 29/0600Z 25.1N 43.4W MAX WIND 110 KT...GUSTS 135 KT. 64 KT... 50NE 50SE 40SW 40NW. 50 KT...120NE 110SE 70SW 90NW. 34 KT...200NE 200SE 120SW 140NW. FORECAST VALID 30/0600Z 28.7N 41.4W MAX WIND 100 KT...GUSTS 120 KT. 50 KT...110NE 110SE 90SW 90NW. 34 KT...200NE 200SE 140SW 140NW. EXTENDED OUTLOOK. NOTE...ERRORS FOR TRACK HAVE AVERAGED NEAR 150 NM ON DAY 4 AND 175 NM ON DAY 5...AND FOR INTENSITY NEAR 15 KT EACH DAY OUTLOOK VALID 01/0600Z 33.3N 37.7W MAX WIND 95 KT...GUSTS 115 KT. OUTLOOK VALID 02/0600Z 40.0N 30.5W MAX WIND 85 KT...GUSTS 105 KT. REQUEST FOR 3 HOURLY SHIP REPORTS WITHIN 300 MILES OF 18.6N 42.1W NEXT ADVISORY AT 27/1500Z $$ FORECASTER ZELINSKY

Issued at 500 AM AST Fri Sep 27 2019 981 WTNT42 KNHC 270850 TCDAT2 Tropical Storm Karen Discussion Number 21 NWS National Hurricane Center Miami FL AL122019 500 AM AST Fri Sep 27 2019 Karen's status as a tropical cyclone is becoming increasingly dubious. In a trio of ASCAT passes that arrived yesterday evening, the circulation of the cyclone was indistinguishable from a surface boundary that extends south from the remnants of post-tropical cyclone Jerry. This suggests that Karen's circulation may no longer be well-defined. Furthermore, deep convection near the center of Karen has generally decreased and become less organized since last night. Satellite-based intensity estimates support maintaining the intensity of Karen at 35 kt, but this could be generous given that the max winds observed in the earlier ASCAT data were lower. Regardless of the exact starting intensity of the cyclone, gradual weakening is expected for the next few days. There is unanimous agreement among the dynamical models on this scenario. Simulated satellite imagery from the GFS and ECMWF models show the cyclone devoid of deep convection within 36 hours, if not sooner. Increasingly hostile upper-level winds should then prevent the cyclone from reorganizing and it is forecast to dissipate in about four days. It has been difficult to locate the center of Karen overnight and the initial motion estimate is uncertain but also unchanged (055/7 kt). The global models are forecasting that Karen will continue to move on this general heading through this morning before it stalls tonight. A building ridge to the north should cause Karen or its remnants to start moving westward over the weekend. FORECAST POSITIONS AND MAX WINDS INIT 27/0900Z 28.3N 61.2W 35 KT 40 MPH 12H 27/1800Z 28.8N 60.1W 35 KT 40 MPH 24H 28/0600Z 29.1N 59.6W 30 KT 35 MPH 36H 28/1800Z 29.3N 60.1W 30 KT 35 MPH...POST-TROP/REMNT LOW 48H 29/0600Z 29.3N 61.3W 25 KT 30 MPH...POST-TROP/REMNT LOW 72H 30/0600Z 29.0N 64.5W 25 KT 30 MPH...POST-TROP/REMNT LOW 96H 01/0600Z...DISSIPATED $$ Forecaster Zelinsky

Issued at 0900 UTC FRI SEP 27 2019 000 FONT12 KNHC 270847 PWSAT2 TROPICAL STORM KAREN WIND SPEED PROBABILITIES NUMBER 21 NWS NATIONAL HURRICANE CENTER MIAMI FL AL122019 0900 UTC FRI SEP 27 2019 AT 0900Z THE CENTER OF TROPICAL STORM KAREN WAS LOCATED NEAR LATITUDE 28.3 NORTH...LONGITUDE 61.2 WEST WITH MAXIMUM SUSTAINED WINDS NEAR 35 KTS...40 MPH...65 KM/H. Z INDICATES COORDINATED UNIVERSAL TIME (GREENWICH) ATLANTIC STANDARD TIME (AST)...SUBTRACT 4 HOURS FROM Z TIME EASTERN DAYLIGHT TIME (EDT)...SUBTRACT 4 HOURS FROM Z TIME CENTRAL DAYLIGHT TIME (CDT)...SUBTRACT 5 HOURS FROM Z TIME WIND SPEED PROBABILITY TABLE FOR SPECIFIC LOCATIONS CHANCES OF SUSTAINED (1-MINUTE AVERAGE) WIND SPEEDS OF AT LEAST ...34 KT (39 MPH... 63 KM/H)... ...50 KT (58 MPH... 93 KM/H)... ...64 KT (74 MPH...119 KM/H)... FOR LOCATIONS AND TIME PERIODS DURING THE NEXT 5 DAYS PROBABILITIES FOR LOCATIONS ARE GIVEN AS OP(CP) WHERE OP IS THE PROBABILITY OF THE EVENT BEGINNING DURING AN INDIVIDUAL TIME PERIOD (ONSET PROBABILITY) (CP) IS THE PROBABILITY OF THE EVENT OCCURRING BETWEEN 06Z FRI AND THE FORECAST HOUR (CUMULATIVE PROBABILITY) PROBABILITIES ARE GIVEN IN PERCENT X INDICATES PROBABILITIES LESS THAN 1 PERCENT PROBABILITIES FOR 34 KT AND 50 KT ARE SHOWN AT A GIVEN LOCATION WHEN THE 5-DAY CUMULATIVE PROBABILITY IS AT LEAST 3 PERCENT. PROBABILITIES FOR 34...50...64 KT SHOWN WHEN THE 5-DAY 64-KT CUMULATIVE PROBABILITY IS AT LEAST 1 PERCENT. - - - - WIND SPEED PROBABILITIES FOR SELECTED LOCATIONS - - - - FROM FROM FROM FROM FROM FROM FROM TIME 06Z FRI 18Z FRI 06Z SAT 18Z SAT 06Z SUN 06Z MON 06Z TUE PERIODS TO TO TO TO TO TO TO 18Z FRI 06Z SAT 18Z SAT 06Z SUN 06Z MON 06Z TUE 06Z WED FORECAST HOUR (12) (24) (36) (48) (72) (96) (120) - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - LOCATION KT $$ FORECASTER ZELINSKY

Issued at 500 AM AST Fri Sep 27 2019 551 WTNT32 KNHC 270846 TCPAT2 BULLETIN Tropical Storm Karen Advisory Number 21 NWS National Hurricane Center Miami FL AL122019 500 AM AST Fri Sep 27 2019 ...KAREN HOLDING ON TO TROPICAL STORM STATUS FOR NOW... ...FORECAST TO BECOME A REMNANT LOW BY SATURDAY... SUMMARY OF 500 AM AST...0900 UTC...INFORMATION ---------------------------------------------- LOCATION...28.3N 61.2W ABOUT 350 MI...565 KM SE OF BERMUDA MAXIMUM SUSTAINED WINDS...40 MPH...65 KM/H PRESENT MOVEMENT...NE OR 55 DEGREES AT 8 MPH...13 KM/H MINIMUM CENTRAL PRESSURE...1005 MB...29.68 INCHES WATCHES AND WARNINGS -------------------- There are no coastal watches or warnings in effect. DISCUSSION AND OUTLOOK ---------------------- At 500 AM AST (0900 UTC), the center of Tropical Storm Karen was located near latitude 28.3 North, longitude 61.2 West. Karen is moving toward the northeast near 8 mph (13 km/h). This general motion is forecast to continue this morning, but Karen is forecast to become nearly stationary by tonight or early Saturday. A westward motion is then anticipated by the end of the weekend. Maximum sustained winds are near 40 mph (65 km/h) with higher gusts. Karen is forecast to degenerate into a remnant low by Saturday. Tropical-storm-force winds extend outward up to 60 miles (95 km) from the center. The estimated minimum central pressure is 1005 mb (29.68 inches). HAZARDS AFFECTING LAND ---------------------- None. NEXT ADVISORY ------------- Next complete advisory at 1100 AM AST. $$ Forecaster Zelinsky

...KAREN HOLDING ON TO TROPICAL STORM STATUS FOR NOW... ...FORECAST TO BECOME A REMNANT LOW BY SATURDAY... As of 5:00 AM AST Fri Sep 27 the center of Karen was located near 28.3, -61.2 with movement NE at 8 mph. The minimum central pressure was 1005 mb with maximum sustained winds of about 40 mph.

Issued at 0900 UTC FRI SEP 27 2019 000 WTNT22 KNHC 270844 TCMAT2 TROPICAL STORM KAREN FORECAST/ADVISORY NUMBER 21 NWS NATIONAL HURRICANE CENTER MIAMI FL AL122019 0900 UTC FRI SEP 27 2019 THERE ARE NO COASTAL WATCHES OR WARNINGS IN EFFECT. TROPICAL STORM CENTER LOCATED NEAR 28.3N 61.2W AT 27/0900Z POSITION ACCURATE WITHIN 45 NM PRESENT MOVEMENT TOWARD THE NORTHEAST OR 55 DEGREES AT 7 KT ESTIMATED MINIMUM CENTRAL PRESSURE 1005 MB MAX SUSTAINED WINDS 35 KT WITH GUSTS TO 45 KT. 34 KT....... 0NE 50SE 50SW 0NW. 12 FT SEAS.. 0NE 60SE 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 28.3N 61.2W AT 27/0900Z AT 27/0600Z CENTER WAS LOCATED NEAR 28.1N 61.5W FORECAST VALID 27/1800Z 28.8N 60.1W MAX WIND 35 KT...GUSTS 45 KT. 34 KT... 0NE 50SE 50SW 0NW. FORECAST VALID 28/0600Z 29.1N 59.6W MAX WIND 30 KT...GUSTS 40 KT. FORECAST VALID 28/1800Z 29.3N 60.1W...POST-TROP/REMNT LOW MAX WIND 30 KT...GUSTS 40 KT. FORECAST VALID 29/0600Z 29.3N 61.3W...POST-TROP/REMNT LOW MAX WIND 25 KT...GUSTS 35 KT. FORECAST VALID 30/0600Z 29.0N 64.5W...POST-TROP/REMNT LOW MAX WIND 25 KT...GUSTS 35 KT. EXTENDED OUTLOOK. NOTE...ERRORS FOR TRACK HAVE AVERAGED NEAR 150 NM ON DAY 4 AND 175 NM ON DAY 5...AND FOR INTENSITY NEAR 15 KT EACH DAY OUTLOOK VALID 01/0600Z...DISSIPATED REQUEST FOR 3 HOURLY SHIP REPORTS WITHIN 300 MILES OF 28.3N 61.2W NEXT ADVISORY AT 27/1500Z $$ FORECASTER ZELINSKY

SPC 0730Z Day 3 Outlook
Day 3 Convective Outlook NWS Storm Prediction Center Norman OK 0230 AM CDT Fri Sep 27 2019 Valid 291200Z - 301200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF THE NORTHERN/CENTRAL PLAINS AND UPPER MIDWEST... ...SUMMARY... At least isolated severe thunderstorms may develop Sunday into Sunday night across parts of the northern/central Plains and the Upper Midwest. ...Northern/Central Plains into the Upper Midwest... A large-scale upper trough/low will remain over a majority of the western CONUS on Sunday. A strong mid/upper-level jet associated with this feature will overspread the northern/central Plains through the period. Even though large-scale forcing for ascent will probably be delayed across much of the northern/central Plains through at least Sunday evening, a pronounced low-level mass response is expected across this region. A surface low is forecast to deepen over the central High Plains through Sunday afternoon, before developing northeastward over SD late. A warm front with rich low-level moisture to its south is likewise expected to shift northward across parts of the central into the northern Plains through Sunday evening/night. Main uncertainty regarding overall severe potential remains initiation of storms across the warm sector, as a low-level temperature inversion will probably limit development through most of the day. Some guidance does show potential for surface-based convection to develop from northeastern NE into eastern SD and southwestern MN late Sunday afternoon and early evening. A low-level jet will likely strengthen to around 40-50+ kt across this region in the same time frame. A strongly veering wind profile with height along with plentiful moisture suggests potential for rotating storms capable of producing all severe hazards, including tornadoes. Isolated large hail may also occur farther north across the Upper Midwest Sunday night with mainly elevated convection, given the presence of strong shear above a near-surface stable layer. ..Gleason.. 09/27/2019 Read more

SPC 0730Z Day 3 Outlook
Day 3 Convective Outlook NWS Storm Prediction Center Norman OK 0230 AM CDT Fri Sep 27 2019 Valid 291200Z - 301200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF THE NORTHERN/CENTRAL PLAINS AND UPPER MIDWEST... ...SUMMARY... At least isolated severe thunderstorms may develop Sunday into Sunday night across parts of the northern/central Plains and the Upper Midwest. ...Northern/Central Plains into the Upper Midwest... A large-scale upper trough/low will remain over a majority of the western CONUS on Sunday. A strong mid/upper-level jet associated with this feature will overspread the northern/central Plains through the period. Even though large-scale forcing for ascent will probably be delayed across much of the northern/central Plains through at least Sunday evening, a pronounced low-level mass response is expected across this region. A surface low is forecast to deepen over the central High Plains through Sunday afternoon, before developing northeastward over SD late. A warm front with rich low-level moisture to its south is likewise expected to shift northward across parts of the central into the northern Plains through Sunday evening/night. Main uncertainty regarding overall severe potential remains initiation of storms across the warm sector, as a low-level temperature inversion will probably limit development through most of the day. Some guidance does show potential for surface-based convection to develop from northeastern NE into eastern SD and southwestern MN late Sunday afternoon and early evening. A low-level jet will likely strengthen to around 40-50+ kt across this region in the same time frame. A strongly veering wind profile with height along with plentiful moisture suggests potential for rotating storms capable of producing all severe hazards, including tornadoes. Isolated large hail may also occur farther north across the Upper Midwest Sunday night with mainly elevated convection, given the presence of strong shear above a near-surface stable layer. ..Gleason.. 09/27/2019 Read more

SPC 0730Z Day 3 Outlook
Day 3 Convective Outlook NWS Storm Prediction Center Norman OK 0230 AM CDT Fri Sep 27 2019 Valid 291200Z - 301200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF THE NORTHERN/CENTRAL PLAINS AND UPPER MIDWEST... ...SUMMARY... At least isolated severe thunderstorms may develop Sunday into Sunday night across parts of the northern/central Plains and the Upper Midwest. ...Northern/Central Plains into the Upper Midwest... A large-scale upper trough/low will remain over a majority of the western CONUS on Sunday. A strong mid/upper-level jet associated with this feature will overspread the northern/central Plains through the period. Even though large-scale forcing for ascent will probably be delayed across much of the northern/central Plains through at least Sunday evening, a pronounced low-level mass response is expected across this region. A surface low is forecast to deepen over the central High Plains through Sunday afternoon, before developing northeastward over SD late. A warm front with rich low-level moisture to its south is likewise expected to shift northward across parts of the central into the northern Plains through Sunday evening/night. Main uncertainty regarding overall severe potential remains initiation of storms across the warm sector, as a low-level temperature inversion will probably limit development through most of the day. Some guidance does show potential for surface-based convection to develop from northeastern NE into eastern SD and southwestern MN late Sunday afternoon and early evening. A low-level jet will likely strengthen to around 40-50+ kt across this region in the same time frame. A strongly veering wind profile with height along with plentiful moisture suggests potential for rotating storms capable of producing all severe hazards, including tornadoes. Isolated large hail may also occur farther north across the Upper Midwest Sunday night with mainly elevated convection, given the presence of strong shear above a near-surface stable layer. ..Gleason.. 09/27/2019 Read more

SPC Day 2 Fire Weather Outlook
Day 2 Fire Weather Outlook NWS Storm Prediction Center Norman OK 0132 AM CDT Fri Sep 27 2019 Valid 281200Z - 291200Z ...Synopsis... Fire weather concerns will revolve around an amplifying trough across the West. This trough will spread strong mid-level flow across much of the Southwest and Great Basin, with vertical mixing processes resulting in strong surface winds. A mid-level ridge will also remain parked across the Deep South. ...Southern Nevada eastward to far western Colorado... Increasing surface winds will exceed 20-25 mph on a widespread basis across the region as a result of the amplifying synoptic pattern, with areas of 30-40 mph flow expected from southeastern Nevada into southwestern Utah. While this flow will be particularly strong, surface temperatures will be relatively cool, and latest guidance depicts that not every locale within the delineated elevated area will experience RH values falling to even elevated thresholds (20-25%) - especially in higher elevations. Nevertheless, fuels guidance suggests the presence of dry fuels beds across the region, which should support an elevated fire weather threat given the strong surface winds. The delineated area may undergo revisions in future outlooks to better highlight areas with sufficiently low RH values. ..Cook.. 09/27/2019 ...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 0132 AM CDT Fri Sep 27 2019 Valid 281200Z - 291200Z ...Synopsis... Fire weather concerns will revolve around an amplifying trough across the West. This trough will spread strong mid-level flow across much of the Southwest and Great Basin, with vertical mixing processes resulting in strong surface winds. A mid-level ridge will also remain parked across the Deep South. ...Southern Nevada eastward to far western Colorado... Increasing surface winds will exceed 20-25 mph on a widespread basis across the region as a result of the amplifying synoptic pattern, with areas of 30-40 mph flow expected from southeastern Nevada into southwestern Utah. While this flow will be particularly strong, surface temperatures will be relatively cool, and latest guidance depicts that not every locale within the delineated elevated area will experience RH values falling to even elevated thresholds (20-25%) - especially in higher elevations. Nevertheless, fuels guidance suggests the presence of dry fuels beds across the region, which should support an elevated fire weather threat given the strong surface winds. The delineated area may undergo revisions in future outlooks to better highlight areas with sufficiently low RH values. ..Cook.. 09/27/2019 ...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 0132 AM CDT Fri Sep 27 2019 Valid 281200Z - 291200Z ...Synopsis... Fire weather concerns will revolve around an amplifying trough across the West. This trough will spread strong mid-level flow across much of the Southwest and Great Basin, with vertical mixing processes resulting in strong surface winds. A mid-level ridge will also remain parked across the Deep South. ...Southern Nevada eastward to far western Colorado... Increasing surface winds will exceed 20-25 mph on a widespread basis across the region as a result of the amplifying synoptic pattern, with areas of 30-40 mph flow expected from southeastern Nevada into southwestern Utah. While this flow will be particularly strong, surface temperatures will be relatively cool, and latest guidance depicts that not every locale within the delineated elevated area will experience RH values falling to even elevated thresholds (20-25%) - especially in higher elevations. Nevertheless, fuels guidance suggests the presence of dry fuels beds across the region, which should support an elevated fire weather threat given the strong surface winds. The delineated area may undergo revisions in future outlooks to better highlight areas with sufficiently low RH values. ..Cook.. 09/27/2019 ...Please see www.spc.noaa.gov/fire for graphic product... Read more