839
FXUS01 KWBC 112024
PMDSPD
SHORT RANGE FORECAST DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
400 PM EDT WED SEP 11 2024
VALID 00Z THU SEP 12 2024 - 00Z SAT SEP 14 2024
...HURRICANE-FORCE WINDS AND LIFE-THREATENING STORM SURGE IMMINENT
ALONG THE LOUISIANA COAST AS FRANCINE MAKES LANDFALL...
...TORRENTIAL RAINFALL FROM FRANCINE WILL SPREAD UP THE
MISSISSIPPI VALLEY WHILE SEVERE WEATHER THREAT SHIFTS EAST INTO
THE FLORIDA PANHANDLE...
...A ROUND OF MODERATE TO HEAVY RAIN WITH HIGH-ELEVATION SNOW WILL
MOVE ACROSS THE NORTHERN ROCKIES...
...ELEVATED TO CRITICAL FIRE WEATHER CONCERNS ACROSS MUCH OF THE
GREAT BASIN AND PORTIONS OF THE HIGH PLAINS...
AS A LARGE AREA OF HIGH PRESSURE CONTINUES TO PROVIDE FINE WEATHER
FROM THE PLAINS TO THE EAST COAST, HURRICANE FRANCINE IN THE GULF
OF MEXICO IS POISED TO MAKE LANDFALL ON THE LOUISIANA COAST LATE
THIS AFTERNOON. SPIRAL RAINBANDS ASSOCIATED WITH THE CORE OF
FRANCINE HAS ALREADY OVERSPREAD THE EASTERN HALF OF LOUISIANA WITH
WINDS CONTINUE TO STRENGTHEN. HURRICANE CONDITIONS CAN BE
EXPECTED TO IMPACT THE COASTAL SECTIONS AS THE EYEWALL OF FRANCINE
ARRIVES WITH LIFE-THREATENING STORM SURGE. FARTHER EAST INTO
SOUTHERN MISSISSIPPI/ALABAMA INTO THE WESTERN FLORIDA PANHANDLE, A
THREAT OF SEVERE THUNDERSTORMS WITH EMBEDDED TORNADOES IS
ANTICIPATED AHEAD OF A COASTAL FRONT LIFTING NORTHWARD FROM THE
GULF OF MEXICO. AS FRANCINE MAKES LANDFALL AND HEADS FARTHER
INLAND, THE TROPICAL CYCLONE WILL INTERACT WITH THE COOLER AND
DRIER AIR MASS THAT HAS BEEN FEEDING SOUTHWARD FROM THE LARGE HIGH
PRESSURE SYSTEM TO THE NORTH. FRANCINE'S INTERACTION WITH THE COOL
AIR MASS AND AN ASSOCIATED UPPER-LEVEL JET STREAM WILL RESULT IN
ITS GRADUAL LOST OF TROPICAL CHARACTERISTIC AS IT MOVES FARTHER
INLAND. THE HEAVY RAINFALL ASSOCIATED WITH FRANCINE WILL THEN
SHIFT FARTHER AWAY FROM FRANCINE'S CENTER, WITH THE THREAT OF
FLASH FLOODING FOCUSING FARTHER NORTH UP THE MID-MISSISSIPPI AND
TENNESSEE VALLEYS ON THURSDAY. BY FRIDAY, FRANCINE IS EXPECTED TO
TRANSFORM INTO A POST-TROPICAL CYCLONE AS IT BEGINS TO STALL
NEAR/OVER THE OZARKS AND GRADUALLY DISSIPATES. THE FOCUS WILL
SHIFT FARTHER EAST FROM THE DEEP SOUTH INTO THE SOUTHEAST AND DOWN
TOWARD THE FLORIDA PANHANDLE FOR POSSIBLE SEVERE THUNDERSTORMS
AHEAD OF A LIFTING WARM FRONT. IN TOTAL, FRANCINE IS EXPECTED TO
PRODUCE RAINFALL AMOUNTS OF 4 TO 8 INCHES, WITH LOCAL AMOUNTS TO
12 INCHES FOR THE CENTRAL/EASTERN GULF COAST THROUGH THURSDAY
NIGHT. THIS RAINFALL COULD LEAD TO CONSIDERABLE FLASH AND URBAN
FLOODING. AS FRANCINE PUSHES NORTHWARD INTO THE MID-SOUTH AND
WEAKENS BY THE END OF THE WEEK, ADDITIONAL HEAVY RAIN IS POSSIBLE
AND COULD LEAD TO SCATTERED INSTANCES OF FLASH FLOODING.
ADDITIONALLY, A LINGERING FRONTAL BOUNDARY DRAPED ACROSS THE
FLORIDA PENINSULA COULD LEAD TO LOCALIZED FLASH FLOODING CONCERNS
OVER THE NEXT FEW DAYS. RESIDENTS UNDER HURRICANE-RELATED
WARNINGS SHOULD FOLLOW ADVICE OF LOCAL OFFICIALS, INCLUDING
EVACUATION ORDERS, AND NEVER DRIVE ACROSS FLOODED ROADWAYS.
MEANWHILE, AN UPPER-LEVEL TROUGH CURRENTLY MOVING ONSHORE INTO THE
PACIFIC NORTHWEST WILL BRING A ROUND OF MODERATE TO HEAVY RAIN
WITH HIGH-ELEVATION SNOW FOR THE NORTHERN ROCKIES THROUGH THURSDAY
NIGHT AS THE DEEPENING UPPER-LEVEL TROUGH BRINGS A SURGE OF COLDER
AIR ACROSS THE REGION. MOST OF THE IMPACTFUL PRECIPITATION WILL
BE CONFINED TO THE NORTHERN ROCKIES AND THE HIGH PLAINS OF
MONTANA. A FEW INCHES OF RAINFALL COULD PRODUCE FLOODING CONCERNS
THROUGHOUT NORTHWEST MONTANA, PROMPTING A SLIGHT RISK (LEVEL 2/4)
OF EXCESSIVE RAINFALL BOTH THROUGH THURSDAY. SNOW LEVELS DROPPING
TO AROUND 7,000-8000 FEET MAY ALSO CREATE HAZARDOUS WINTER-LIKE
CONDITIONS FOR THE HIGHEST ELEVATIONS OF IDAHO AND NORTHWEST
WYOMING. THE OTHER ASPECT OF THIS SYSTEM WILL BE ASSOCIATED WITH
GUSTY WINDS AND INCREASED FIRE WEATHER CONCERNS THROUGHOUT THE
GREAT BASIN AND HIGH PLAINS. STRONG WINDS COMBINED WITH DRY
VEGETATION AND LOW RELATIVE HUMIDITY ARE FORECAST TO BE MORE
PRONOUNCED OVER THE GREAT BASIN TODAY AND INCREASE THE CHANCES FOR
ERRATIC FIRE BEHAVIOR. ADDITIONALLY, ELEVATED TO CRITICAL FIRE
WEATHER ALSO EXISTS ACROSS THE HIGH PLAINS AND IS MOST APPARENT ON
THURSDAY AS SOUTHERLY WINDS INCREASE IN SPEED. RED FLAG WARNINGS
AND FIRE WEATHER WATCHES HAVE BEEN ISSUED THROUGHOUT 10 STATES
BETWEEN CALIFORNIA AND NEBRASKA. OUTDOOR BURNING IS NOT
RECOMMENDED THROUGHOUT THESE REGIONS AND RESIDENTS ARE REMINDED TO
NOT GO NEAR ANY WILDFIRES AS THEY CAN SPREAD QUICKLY. THE GUSTY
WINDS AND FIRE WEATHER DANGER WILL SHIFT INTO THE NORTHERN AND
CENTRAL HIGH PLAINS ON THURSDAY AND INTO FRIDAY AS A SHARP FRONT
PASSES THROUGH AND A COUPLE OF LOW PRESSURE SYSTEM DEVELOP.
OTHERWISE, TRANQUIL WEATHER WILL PREVAIL FROM THE GREAT LAKES TO
MUCH OF THE EAST UNDER THE LARGE HIGH PRESSURE SYSTEM. WELL ABOVE
AVERAGE TEMPERATURES ARE EXPECTED TO OVERSPREAD THE NORTH-CENTRAL
U.S. BEFORE A WARMING TREND IS ALSO NOTICEABLE ACROSS THE SOUTHERN
PLAINS BY FRIDAY. HIGHS ACROSS THE NORTHERN PLAINS, UPPER
MIDWEST, AND GREAT LAKES ARE FORECAST TO REACH INTO THE UPPER 80S
AND LOW 90S, WHILE UPPER 90S EVENTUALLY RETURN TO THE WESTERN HALF
OF TEXAS AND EASTERN NEW MEXICO.
KONG/SNELL
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