963
FXUS01 KWBC 181929
PMDSPD
SHORT RANGE FORECAST DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
328 PM EDT WED SEP 18 2024
VALID 00Z THU SEP 19 2024 - 00Z SAT SEP 21 2024
...HEAVY RAINFALL AND FLASH FLOODING POSSIBLE IN MONTANA THROUGH
TONIGHT...
...SEVERE THUNDERSTORMS POSSIBLE IN THE NORTHERN/CENTRAL PLAINS
AND UPPER MIDWEST THROUGH THURSDAY...
...LATE-SUMMER HEAT FORECAST THROUGHOUT PARTS OF THE SOUTHERN
PLAINS...
A STRONG OCCLUDED LOW WILL BRING HAZARDOUS WEATHER TO MONTANA
THROUGH TONIGHT AS IT LINGERS OVER THE STATE. STRONG UPSLOPE FLOW
ALONG THE NORTHERN ROCKIES AND CENTRAL MONTANA RANGES ON THE
BACKSIDE OF THE LOW WILL RESULT IN SHOWERS AND THUNDERSTORMS WITH
VERY HEAVY RAINFALL TOTALS. A SLIGHT RISK OF EXCESSIVE RAINFALL
(LEVEL 2/4) IS IN EFFECT FOR PORTIONS OF MONTANA WHERE SCATTERED
FLASH FLOODING WILL BE POSSIBLE. WINTRY PRECIPITATION WILL ALSO BE
POSSIBLE IN THE HIGH ELEVATIONS OF THE NORTHERN ROCKIES. IN
ADDITION TO PRECIPITATION HAZARDS, A STRONG PRESSURE GRADIENT IN
THE VICINITY OF THE CENTRAL LOW WILL RESULT IN STRONG, GUSTY WINDS
ACROSS THE REGION, INCLUDING INTO PARTS OF THE NORTHERN PLAINS.
HIGH WIND WATCHES AND WARNINGS ARE IN EFFECT FOR PORTIONS OF
MONTANA AND WYOMING WHERE WINDS ARE FORECAST TO BE 30-40 MPH WITH
GUSTS UP 60 MPH. THE LOW WILL GRADUALLY LIFT NORTH INTO SOUTHERN
CANADA THURSDAY AND FRIDAY, AND RAIN AND WINDS WILL BEGIN TO
RELAX.
THE STRONG LOW PRESSURE SYSTEM WILL ALSO PUSH A COLD FRONT ACROSS
THE PLAINS AND UPPER MIDWEST THROUGH FRIDAY. A LINE OF SHOWERS AND
THUNDERSTORMS WILL MOVE EAST AHEAD OF THE COLD FRONT, AND THE
ENVIRONMENT WILL SUPPORT THE DEVELOPMENT OF SCATTERED SEVERE
THUNDERSTORMS. THE STORM PREDICTION CENTER HAS HIGHLIGHTED
PORTIONS OF THE PLAINS AND UPPER MIDWEST WITH A SLIGHT RISK OF
SEVERE THUNDERSTORMS (LEVEL 2/5) TODAY AND AGAIN ON THURSDAY.
POTENTIAL SEVERE STORM HAZARDS WILL INCLUDE DAMAGING WIND GUSTS,
LARGE HAIL, AND A FEW TORNADOES. SHOWER AND THUNDERSTORM COVERAGE
WILL EXPAND INTO THE GREAT LAKES, MID-MISSISSIPPI AND OHIO VALLEYS
ON FRIDAY AS THE COLD FRONT CONTINUES TO TREK EAST.
ELSEWHERE, TWO COASTAL LOWS WILL SANDWICH THE CONTINENTAL UNITED
STATES, ONE MOVING SOUTH ALONG THE WEST COAST AND ONE MOVING NORTH
ALONG THE EAST COAST. THE WEST COAST LOW WILL BRING PRECIPITATION
TO THE GREAT BASIN AND CALIFORNIA TONIGHT INTO THURSDAY.
PRECIPITATION WILL FALL MAINLY IN THE FORM OF SHOWERS AND
THUNDERSTORMS, BUT SOME WINTRY PRECIPITATION WILL BE POSSIBLE IN
THE SIERRA NEVADA. THE LOW WILL WEAKEN ON FRIDAY, AND
PRECIPITATION WILL TAPER OFF. THE EAST COAST LOW WILL GRADUALLY
DEEPEN OFFSHORE OF THE MID-ATLANTIC OVER THE NEXT FEW DAYS WITH A
SLOW-MOVING FRONTAL BOUNDARY EXTENDING SOUTHWEST FROM THE LOW.
SHOWERS AND STORMS CAPABLE OF LOCALIZED INTENSE RAINFALL WILL BE
POSSIBLE FOR THE MID-ATLANTIC, COASTAL NORTHEAST, SOUTHEAST, AND
FLORIDA. THIS SYSTEM WILL ALSO PRODUCE GUSTY WINDS OVER THE
COASTAL WATERS, WHICH HAS PROMPTED SMALL CRAFT AND COASTAL FLOOD
ADVISORIES ALONG THE MID-ATLANTIC COAST.
TEMPERATURE-WISE, THE WEST WILL EXPERIENCE WELL BELOW AVERAGE
TEMPERATURES IN THE WAKE OF THE STRONG FRONTAL SYSTEM IN THE
PLAINS, WHILE THE CENTRAL U.S. EXPERIENCES WELL ABOVE AVERAGE
SUMMER-LIKE TEMPERATURES WITH SOUTHERLY FLOW AHEAD OF THE PLAINS
SYSTEM. A FEW NEAR-RECORD HIGH TEMPERATURES WILL BE POSSIBLE IN
THE SOUTHERN PLAINS WHERE HIGHS WILL APPROACH THE UPPER 90S AND
NEAR 100 DEGREES, INCLUDING THE OKLAHOMA CITY METRO REGION. ABOVE
AVERAGE TEMPERATURES WILL ALSO BE OBSERVED IN THE INTERIOR
NORTHEAST UNDER AN UPPER LEVEL RIDGE, AND NEAR TO SLIGHTLY BELOW
NORMAL TEMPERATURES WILL BE OBSERVED IN THE MID-ATLANTIC AND
SOUTHEAST.
DOLAN/SNELL
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