217
FXUS01 KWBC 260750
PMDSPD
SHORT RANGE FORECAST DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
350 AM EDT THU SEP 26 2024
VALID 12Z THU SEP 26 2024 - 12Z SAT SEP 28 2024
...HELENE IS FORECAST TO RAPIDLY INTENSIFY TO A MAJOR HURRICANE IN
THE GULF TODAY AND BRING LIFE-THREATENING IMPACTS TO FLORIDA AND
THE SOUTHEAST THROUGH FRIDAY...
...RARE HIGH RISKS OF EXCESSIVE RAINFALL ARE IN PLACE FOR PARTS OF
THE FLORIDA PANHANDLE WHERE HELENE WILL MAKE LANDFALL, AND FOR THE
SOUTHERN APPALACHIANS WHERE CATASTROPHIC FLASH FLOODING AND
LANDSLIDES ARE EXPECTED...
...ABOVE AVERAGE TEMPERATURES AND SUMMER-LIKE WARMTH FORECAST TO
STRETCH FROM THE SOUTHWEST TO NORTHERN PLAINS...
HURRICANE HELENE IS MOVING NORTHWARD THROUGH THE GULF OF MEXICO
THIS MORNING AND IS FORECAST TO BECOME A MAJOR HURRICANE BEFORE
MAKING LANDFALL. POTENTIALLY CATASTROPHIC HURRICANE-FORCE WINDS
ARE EXPECTED WITHIN THE EYEWALL OF HELENE WHEN IT MAKES LANDFALL
IN THE FLORIDA BIG BEND REGION THIS EVENING. BECAUSE HELENE IS
BECOMING A LARGE SYSTEM AND WILL INITIALLY MOVE INLAND QUICKLY,
DAMAGING AND LIFE-THREATENING HURRICANE-FORCE WINDS, ESPECIALLY IN
GUSTS, WILL PENETRATE WELL INLAND OVER PORTIONS OF NORTHERN
FLORIDA AND SOUTHERN GEORGIA LATE THURSDAY AND THURSDAY NIGHT
WHERE HURRICANE WARNINGS ARE IN EFFECT. STRONG WIND GUSTS ARE ALSO
LIKELY FARTHER NORTH ACROSS PORTIONS OF NORTHERN GEORGIA AND THE
CAROLINAS, PARTICULARLY OVER THE HIGHER TERRAIN OF THE SOUTHERN
APPALACHIANS. ADDITIONALLY, CATASTROPHIC AND DEADLY STORM SURGE IS
LIKELY ALONG PORTIONS OF THE FLORIDA BIG BEND COAST, WHERE
INUNDATION COULD REACH AS HIGH AS 20 FEET ABOVE GROUND LEVEL,
ALONG WITH DESTRUCTIVE WAVES. THERE IS ALSO A DANGER OF
LIFE-THREATENING STORM SURGE ALONG THE REMAINDER OF THE WEST COAST
OF THE FLORIDA PENINSULA. PREPARE NOW AND HEED INSTRUCTIONS FROM
LOCAL OFFICIALS ABOUT EVACUATIONS IN THESE AREAS. PLEASE REFER TO
THE NATIONAL HURRICANE CENTER FOR THE LATEST UPDATES ON THE TRACK
AND TIMING OF HELENE.
HELENE WILL ALSO CAUSE SIGNIFICANT RAINFALL AND FLOODING THREATS.
EVEN AHEAD OF HELENE ITSELF, TROPICAL MOISTURE CONTINUES TO BE
PULLED NORTH INTO THE SOUTHEAST TO SOUTHERN APPALACHIANS AHEAD OF
A SLOW-MOVING UPPER TROUGH/LOW AND SURFACE FRONT, CURRENTLY
CAUSING RAINFALL AND FLOODING THAT WILL LAST THROUGH THE DAY.
HEAVY TO EXTREME RAINFALL FROM YESTERDAY HAS ALSO LED TO WET
ANTECEDENT CONDITIONS IN PLACES WHERE HELENE WILL TRACK. A RARE
HIGH RISK (LEVEL 4/4) REMAINS IN PLACE IN WPC'S EXCESSIVE RAINFALL
OUTLOOK (ERO) ACROSS PORTIONS OF GEORGIA INTO THE SOUTHERN
APPALACHIANS WHERE UPSLOPE FLOW SHOULD INCREASE RAIN TOTALS AND
VARYING TERRAIN IS LIKELY TO LEAD TO LANDSLIDES. ADDITIONALLY, A
SEPARATE AREA OF EXTREME RAINFALL IS ALSO LIKELY NEAR THE CORE OF
THE STORM AS IT PASSES OVER THE FLORIDA PANHANDLE, WHERE A
SEPARATE HIGH RISK IS IN EFFECT IN THE DAY 1 ERO. A BROAD SLIGHT
RISK (LEVEL 2/4) WITH AN EMBEDDED MODERATE RISK (LEVEL 3/4) OVER
THE APPALACHIANS IS IN PLACE FOR FRIDAY FOR CONTINUED RAINFALL.
OVERALL, HELENE IS FORECAST TO PRODUCE TOTAL RAIN ACCUMULATIONS OF
6 TO 12 INCHES, WITH ISOLATED TOTALS AROUND 20 INCHES, OVER
PORTIONS OF THE SOUTHEAST INTO SOUTHERN APPALACHIANS. CATASTROPHIC
AND LIFE-THREATENING FLASH AND URBAN FLOODING, INCLUDING NUMEROUS
SIGNIFICANT LANDSLIDES, IS EXPECTED ACROSS PORTIONS OF THE
SOUTHERN APPALACHIANS THROUGH FRIDAY. CONSIDERABLE TO LOCALLY
CATASTROPHIC FLASH AND URBAN FLOODING IS LIKELY FOR NORTHWESTERN
AND NORTHERN FLORIDA AND THE SOUTHEAST THROUGH FRIDAY. WIDESPREAD
SIGNIFICANT RIVER FLOODING AND ISOLATED MAJOR RIVER FLOODING ARE
LIKELY. ANOTHER WEATHER HAZARD ASSOCIATED WITH HELENE TO MONITOR
IS THE TORNADO THREAT, ESPECIALLY ON THE EASTERN SIDE OF THE
TRACK. THE STORM PREDICTION CENTER IS INDICATING A SLIGHT TO
ENHANCED RISK OF SEVERE WEATHER, PRIMARILY FOR TORNADOES, TODAY
INTO TONIGHT FOR PARTS OF FLORIDA INTO GEORGIA AND SOUTH
CAROLINA/SOUTHEASTERN NORTH CAROLINA.
ELSEWHERE, SHOWERS AND STORMS ARE ALSO POSSIBLE FARTHER NORTH IN
THE EASTERN U.S. ALONG THE NORTHERN PART OF THE FRONTAL SYSTEM
OVER THE NEXT COUPLE OF DAYS. A COUPLE OF FRONTS PASSING THROUGH
THE NORTHWEST SHOULD LEAD TO SOME PRECIPITATION THERE AND GUSTY
WINDS. MEANWHILE THE REST OF THE WESTERN U.S. STRETCHING INTO THE
NORTH-CENTRAL U.S. CAN EXPECT DRY CONDITIONS WITH WARMER THAN
AVERAGE TEMPERATURES. THE DESERT SOUTHWEST WILL SEE HIGHS WELL
INTO THE 100S AND LOW 110S, WHICH HAS PROMPTED EXCESSIVE HEAT
WARNINGS FROM SOUTH-CENTRAL ARIZONA INTO THE HIGH DESERTS OF
SOUTHERN CALIFORNIA. HIGH INTO THE 90S ARE LIKELY IN THE NORTHERN
HIGH PLAINS TODAY, WITH 80S STRETCHING INTO THE UPPER MIDWEST
THROUGH THE END OF THE WEEK. RECORD WARM TEMPERATURES ARE POSSIBLE
FOR BOTH MORNING LOWS AND AFTERNOON HIGHS.
TATE
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