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SPC 2000Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0254 PM CDT Tue Sep 26 2023 Valid 262000Z - 271200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS THE MS AND UPPER OH VALLEY...NM AND WEST TX...AND NORTHERN FL... ...SUMMARY... Isolated severe thunderstorms are possible today across parts of the Midwest, across parts of New Mexico into west Texas, and possibly northern Florida. ...20Z Update... ...Mid MS Valley into the Lower OH Valley... Visible satellite imagery shows a cumulus field from IA across IL into IN, with some recent building cumulus across eastern MO as well. All of this is occurring in the vicinity of an upper low centered over eastern IA. MCD #2198 was recently issued addressing the severe potential in this area. As mentioned in that discussion, cold mid-level temperatures and steep low-level lapse rates, and resulting modest buoyancy, in the presence of low-level vorticity may result in isolated instances of hail and perhaps a brief tornado this afternoon. An associated occluded surface low is centered below this upper low, linked to another surface low over northeast IL by a weak surface trough. A cold front extends from arc second low southward into southern IL and then back westward into west-central MO. As mentioned in MCD #2200, pulse-cells and multicell storms have been increasing in coverage and intensity along this boundary. A couple instances of hail are possible with the stronger storms this afternoon. Building cumulus across far southwest MO suggests thunderstorm initiation will occur in that region as well, and marginal hail and wind probabilities were extended accordingly. ...Elsewhere... Isolated thunderstorms capable of hail and damaging gusts remain possible across NM and West TX. A strong storm or two is also possible across northern FL, as mentioned in MCD #2199. ..Mosier.. 09/26/2023 .PREV DISCUSSION... /ISSUED 1136 AM CDT Tue Sep 26 2023/ ...Midwest including Illinois/Indiana/Missouri... An upper low (-16C at 500mb) centered over eastern Iowa this morning will continue to drift east-southeastward toward and across northern Illinois through tonight. A semi-moist environment, with surface dewpoints in the upper 50s/low 60s F, will diurnally persist near/northeast of a weak surface low and occluded front/wind shift that will generally extend southeastward from the surface low. While deep-layer wind profiles will generally be weak (15-20 kt effective shear), ample CAPE with respect to low-topped storms will support the possibility of hail with the stronger pulse-type cells. Funnels appear quite plausible across areas including eastern Iowa, southern Wisconsin and northern/central Illinois, and sufficient low-level CAPE/ambient vorticity near the boundary could yield a brief tornado risk. Farther to the southwest, there is some potential that some strong to severe thunderstorms could develop near the front across central/eastern Missouri late this afternoon into tonight. MLCAPE could reach 1000-1500 J/kg MLCAPE near/south of the front, and wind profiles will be moderately strong, influenced by increasingly strong cyclonically curved westerlies in the base of the Upper Midwest shortwave trough. Thermodynamic/kinematic profiles could conditionally support some high-based supercells aside from multicellular clusters if/where storms develop. While near-frontal convergence will be modest, and the likelihood and extent of sustained deep convection may remain limited, there will be additional late night opportunities for convective development as warm advection/moisture transport increase, and some of these storms could also be strong. This region will be closely reevaluated in subsequent outlooks for a potential reintroduction of severe probabilities. ...New Mexico/West Texas... Within the weaker southern branch of westerlies, a weak shortwave trough is expected to move southeastward across the Four Corners vicinity through tonight. As it does, associated forcing for ascent should augment convective development, particularly storms initiating in response to heating across the mountains of southern/central New Mexico by early afternoon. It appears that moisture across this region will be sufficient to support initially sizable CAPE, beneath modest westerly to northwesterly flow, at least in upper levels. Stronger storms may become capable of producing marginally severe hail, then a few strong to severe gusts while propagating southeastward off the higher terrain into an unstable and more deeply mixed boundary-layer through early this evening. ...Florida Peninsula... Low severe probabilities have been introduced for the northern Florida Peninsula where storms are expected to increase/develop east-northeastward across the region, all while deep-layer shear modestly increases. High precipitable water content will support heavy precipitation loading and some potential for locally strong surface gusts. ...Coastal Oregon... Forcing for ascent within the exit region of a strong jet streak (including 70-90 kt around 500 mb) may contribute to an organized, vigorous pre-frontal convective band, associated with the surface cyclone approaching the Pacific Northwest. However, with the cyclone forecast to occlude prior to reaching the coast near/after 27/06Z, appreciable inland boundary-layer destabilization appears unlikely, and stable near-surface lapse rates may tend to mitigate the potential for downward mixing of severe surface gusts as the convective line progresses inland. Read more

Canyon Lake continued to drop below its lowest point in recorded history as drought persisted in Texas. The low level of the lake exposed caves that were previously underwater, but were now accessible by boat. Divers also found remnants of two towns, Hancock and Crane’s Mill, that were hidden by the lake’s waters when Canyon Lake was formed. KSAT 12 Online (San Antonio, Texas), Sept 26, 2023

SPC Day 2 Fire Weather Outlook
Day 2 Fire Weather Outlook NWS Storm Prediction Center Norman OK 0239 PM CDT Tue Sep 26 2023 Valid 271200Z - 281200Z ...NO CRITICAL AREAS... No changes are needed to the D2 Fire Weather Outlook. See previous discussion below for more information. ..Thornton.. 09/26/2023 .PREV DISCUSSION... /ISSUED 0125 AM CDT Tue Sep 26 2023/ ...Synopsis... Fire weather potential is forecast to remain low for Wednesday. The upper low currently moving into the Pacific Northwest will continue to push eastward into the northern Rockies through Wednesday. Ahead of an attendant cold front, breezy southwesterly winds will advect a dry air mass (currently over the western Great Basin) into UT and WY. Latest ensemble and deterministic guidance show a reasonably consistent signal for areas of 15-25 mph sustained winds with RH values generally in the upper teens to 20s. Consequently, patchy elevated fire weather conditions are probable from central UT to central WY Wednesday afternoon. Across southern CA, Sundowner winds across Santa Barbara county may be strong at the start of the forecast period and persist through much of the day. Downslope warming/drying should produce localized pockets of reduced RH into the low 20s. For both regions, however, recent analyses suggest fuels are currently not receptive, which should modulate the overall fire weather concern. Fuel trends will be monitored across southern CA where locally dry/windy conditions may persist for 12+ hours and support drying of fine fuels. ...Please see www.spc.noaa.gov/fire for graphic product... Read more

000
ABPZ20 KNHC 261722
TWOEP

Tropical Weather Outlook
NWS National Hurricane Center Miami FL
1100 AM PDT Tue Sep 26 2023

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

Southwestern East Pacific:
A tropical wave located well southwest of the southern tip of the
Baja California peninsula continues to produce disorganized showers
and thunderstorms. Some slow development of this system is possible
over the next few days while it moves generally westward at about 15
mph. By this weekend, upper-level winds are forecast to become
unfavorable for further development while the system moves into the
Central Pacific basin.
* Formation chance through 48 hours...low...10 percent.
* Formation chance through 7 days...low...20 percent.

$$
Forecaster Reinhart

Historic drought in Louisiana has rats and mice seeking food and water in people’s homes. Since rodents carry more than 60 different diseases, residents should aim to find entry points and fix them if possible and take measures necessary to eliminate the pests. Louisiana Radio Network (Baton Rouge, La.), Sept 26, 2023

As saltwater intrusion continued to result in poorer quality water in Plaquemines Parish, grocery stores were working hard to keep bottles of water on store shelves, residents were getting rashes after showering, and people were frustrated with the water situation. A parish councilman stated that they were praying for rain to increase the flow of the Mississippi River. Gov. John Bel Edwards cautioned that more towns further up the Mississippi River, including Orleans, St. Bernard and Jefferson, may soon be affected by the salt water in mid-to-late October. In addition, millions of gallons of fresh water were being moved by barges to treatment facilities in impacted areas. Associated Press News (Baton Rouge, La.), Sept 25, 2023

The U.S. Army Corps of Engineers intends to barge 36 million gallons of fresh water daily to local water treatment facilities to create a water mixture safe for treatment. The increased salinity from the saltwater intrusion is predicted to exceed the Environmental Protection Agency’s maximum standard of 250 mg/L in some areas, affecting public water systems and bringing the risk of corrosion to water distribution systems, machinery, and appliances, according to the governor’s office. Bottled water in bulk will also be delivered to the New Orleans area. CNN (Atlanta, Ga.), Sept 24, 2023

Apples grown at an orchard in Elgin were nice with few defects or other issues, but the apples were slightly smaller than usual. The pumpkin and squash crops failed because an irrigation system installed this summer was not operable soon enough to save those crops. KTTC-TV Rochester (Minn.), Sept 25, 2023

No watches are valid as of Mon Sep 25 22:34:02 UTC 2023.

No Mesoscale Discussions are in effect as of Mon Sep 25 22:34:02 UTC 2023.

SPC Day 3-8 Fire Weather Outlook
Day 3-8 Fire Weather Outlook NWS Storm Prediction Center Norman OK 0358 PM CDT Mon Sep 25 2023 Valid 271200Z - 031200Z The large scale pattern will consist of a trough across the western US with downstream ridging across the eastern US. This will bring periods of breezy conditions across the southwest as multiple waves move through the longwave trough. Sundowner winds will be possible late D2 - Tuesday into D3 - Wednesday across the Santa Ynez Mountains into the Santa Barbra foothills in southern California with poor overnight recovery. Elevated to locally Critical fire weather conditions will be possible. Due to the localized nature of this threat, no probabilities were included at this time. Toward the end of the extended period, the western trough will begin to dig southward and slowly progress eastward. The enhancement of the upper-level flow will bring potential for strengthening winds across the southwest and adjacent central high plains as a surface trough begins to develop in the lee of the Rockies. Periods of Elevated to Critical fire weather will be possible but confidence is low in where windy/dry conditions will overlap receptive fuels. As such, no probabilities have been included at this time but trends will be monitored in the coming days. ..Thornton.. 09/25/2023 ...Please see www.spc.noaa.gov/fire for graphic product... Read more

SPC 2000Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0254 PM CDT Mon Sep 25 2023 Valid 252000Z - 261200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS THE FLORIDA PENINSULA AND SOUTH TEXAS TO SOUTHWEST LOUISIANA... ...SUMMARY... Isolated severe thunderstorms remain possible across southern parts of Texas, southwestern Louisiana, and the Florida Peninsula late this afternoon into this evening. ...20Z Update... No changes have been made to the severe probabilities. Isolated strong to potentially severe thunderstorms remain possible across parts of the FL Peninsula, and also across southern parts of Texas into southwest LA. See the previous discussion below for more information. Also see MCD 2196 for more information regarding the short-term threat near the upper TX coast. ..Dean.. 09/25/2023 .PREV DISCUSSION... /ISSUED 1130 AM CDT Mon Sep 25 2023/ ...Southern Texas/southwest Louisiana... Multiple areas of widely scattered showers and thunderstorms, generally in a weakening/diminishing trend through mid/late morning, exist across the region. Additional widely scattered thunderstorm development is expected to uptick in coverage and intensity later this afternoon, influenced by the southward-sagging front as well as several zones of outflow/differential heating. Multicellular storms will be common, with some potential for a few supercells particularly with westward extent across south-central/southwest Texas toward the Rio Grande, where deep-layer shear and buoyancy will be a bit stronger and where large hail potential is more apparent. This is aside from the potential for isolated severe wind gusts that will more broadly exist across the region. ...Central/southern Florida... Scattered thunderstorms are expected to develop across the region this afternoon. Localized strong/severe wind gusts are possible along with the possibility of marginally severe hail. This regime is the east of upper troughing over the central/northeast Gulf of Mexico, with a moist environment (PW 1.75-2.25-inches) existing across much of the Peninsula, with sea breeze boundaries focusing increasing diurnal thunderstorm development. While deep-layer winds will be weak, veering with height will contribute to 20-30 kt effective-shear magnitudes, supporting multicellular storm organization. Convection should diminish in coverage and strength after sunset as a combination of nocturnal cooling and increasingly prevalent outflow air stabilizes the boundary layer inland. ...Southeast MN/western WI/northeast IA/northwest IL... A few funnels may occur this afternoon across the region in relative proximity to the southeastward-moving upper low (-16C at 500mb), focused near the surface occluded front that will be located near the Mississippi River, and generally oriented parallel to it. There is where low-level buoyancy including 100-125 J/kg 0-3 km CAPE will be maximized with ambient vorticity. While a tornado cannot be entirely discounted, the potential for such currently appears to be very low, while funnels/briefly strong storms are otherwise plausible within the weak vertical shear environment (effective/0-6 km shear magnitudes less than 20 kt). Read more

SPC Day 2 Fire Weather Outlook
Day 2 Fire Weather Outlook NWS Storm Prediction Center Norman OK 0248 PM CDT Mon Sep 25 2023 Valid 261200Z - 271200Z ...NO CRITICAL AREAS... No changes are needed to the D2 Fire Weather Outlook. See previous discussion below for more information. ..Thornton.. 09/25/2023 .PREV DISCUSSION... /ISSUED 0140 AM CDT Mon Sep 25 2023/ ...Synopsis... Fire weather concerns will remain limited for Tuesday. Strong low- to mid-level winds will continue to overspread the Pacific Northwest and into the northern Rockies through Tuesday. However, cooler temperatures and cloud cover behind an eastward-progressing cold front will modulate RH reductions for much of the region. Dry and breezy conditions will primarily be confined to immediately ahead of the front, but recent ensemble guidance depicts fairly low probability for sustained/widespread 15+ mph winds and sub-20% RH over areas with dry fuels. Sustained elevated fire weather conditions are most probable within the higher terrain of central ID to southwest MT, but ERCs across this region are near seasonally normal values. ...Please see www.spc.noaa.gov/fire for graphic product... Read more

The ground was so dry across southeast Alabama that peanut farmers were having trouble unearthing the peanuts because little rain has fallen recently, leaving the ground very hard. Rain would still be beneficial in maturing some of the peanuts. WDHN-TV ABC 18 Dothan (Ala.), Sept 23, 2023

000
ABPZ20 KNHC 251753
TWOEP

Tropical Weather Outlook
NWS National Hurricane Center Miami FL
1100 AM PDT Mon Sep 25 2023

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

Tropical cyclone formation is not expected during the next 7 days.

$$
Forecaster Roberts

Lake Marburg in Codorus State Park has receded to reveal an old lake bridge. Hikers noticed cinder blocks and concrete recently. The bridge was part of the old village of Marburg, before it was abandoned to make way for the lake. FOX 43 (Harrisburg, Pa.), Sept 22, 2023

The owner of a pecan orchard in Seguin was inspecting his trees and was worried after finding 59 mature trees that died after a hot, dry summer. Thirty-eight trees younger than five years old have also died. The orchard owner has some limited irrigation capability, but the trees needed more water and relief from the intense heat. KXAN Online (Austin, Texas), Sept 25, 2023

The Tillamook Board of County Commissioners declared a local state of emergency due to drought on September 20. The need for such a declaration is highly unusual because the county typically receives more than 100 inches of rain annually. Some wells have run dry, and the Office of Resiliency and Emergency Management was delivering water. Because the area is usually flush with water, there were no companies operating potable water tanker trucks on the north coast, and few statewide. Tillamook Headlight Herald (Ore.), Sept 25, 2023

The mayor of New Orleans signed an emergency declaration over saltwater intrusion in the Mississippi River that is affecting water supplies in Plaquemines Parish. Weather forecasts suggest that river volume will drop to historic lows in the next several weeks. An underwater sill was constructed to slow movement of the saltwater in July, but the barrier was overtopped, so additional work to expand the sill will be untaken to keep the saltwater downriver. It is thought that saltwater intrusion can be delayed by roughly 10 to 15 days. ABC News, Sept 23, 2023