793
FXUS01 KWBC 130725
PMDSPD
SHORT RANGE FORECAST DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
324 AM EDT SAT MAY 13 2023
VALID 12Z SAT MAY 13 2023 - 12Z MON MAY 15 2023
...HEAVY RAIN, FLASH FLOODING AND SEVERE WEATHER LIKELY FROM THE
GREAT PLAINS TO THE MIDWEST...
...MUCH ABOVE AVERAGE TO RECORD HEAT BUILDING ACROSS THE PACIFIC
NORTHWEST, WHILE BELOW AVERAGE TEMPERATURES EXPECTED ACROSS LARGE
PORTIONS OF THE PLAINS...
PULSES OF SHORTWAVE ENERGY WILL CONTINUE TO STIR UP ENOUGH
MOISTURE AND INSTABILITY TO CAUSE HEAVY RAINFALL, FLASH FLOODING
AND SEVERE WEATHER ACROSS PARTS OF THE GREAT PLAINS AND MIDWEST
TODAY. A MODERATE RISK OF EXCESSIVE RAINFALL LEADING TO FLASH
FLOODING IS IN PLACE OVER SOUTH TEXAS AND THE WESTERN GULF COAST
FOR TODAY, WHERE BETWEEN 3-5"+ RAINFALL TOTALS AND HOURLY RAINFALL
RATES GREATER THAN 1-2" ARE EXPECTED TO BE ASSOCIATED WITH A MCS
MOVING THROUGH THE COASTAL PLAIN EARLY THIS MORNING. THIS MEANS
THAT THERE WILL LIKELY BE SCATTERED TO NUMEROUS INSTANCES OF FLASH
FLOODING. A BROADER SLIGHT RISK AREA ENCOMPASSES MUCH OF
CENTRAL/EASTERN TEXAS AS WELL AS SOUTHERN OKLAHOMA. THE STORM
PREDICTION CENTER ISSUED A SLIGHT RISK OF SEVERE THUNDERSTORMS FOR
PORTIONS OF THE TEXAS COASTAL PLAIN AS THE AFOREMENTIONED COMPLEX
LIKELY PRODUCES WIND DAMAGE AND ISOLATED LARGE HAIL. THE FLASH
FLOODING AND SEVERE THREAT WILL RAPIDLY DIMINISH LATER THIS
MORNING AS MUCH OF THE INSTABILITY MOVES OFFSHORE. ELSEWHERE,
SLIGHT RISKS OF EXCESSIVE RAINFALL LEADING TO FLASH FLOODING AS
WELL AS SEVERE THUNDERSTORMS ARE IN EFFECT FOR PARTS OF THE
SOUTHERN MINNESOTA INTO WESTERN ILLINOIS THANKS TO THE PRESENCE OF
A STATIONARY FRONT AND A SUFFICIENT THERMODYNAMIC ENVIRONMENT TO
SUPPORT DISCREET SUPERCELLS CAPABLE OF PRODUCING A FEW TORNADOES,
WIND DAMAGE AND LARGE HAIL. RAINFALL TOTALS OF 1-2" ARE ALSO
EXPECTED OVER PARTS OF SOUTHERN MINNESOTA AND IOWA.
WHILE THE CONVECTIVE THREAT SUBSIDES BY SUNDAY, HEAVY RAINFALL AND
FLASH FLOODING CONCERNS DO NOT OVER PORTIONS OF THE
CENTRAL/SOUTHERN PLAINS. SLIGHT RISKS OF EXCESSIVE RAINFALL
LEADING TO FLASH FLOODING ARE IN EFFECT FOR PORTIONS OF
SOUTHEASTERN COLORADO INTO THE TEXAS/OKLAHOMA PANHANDLE AS WELL AS
ANOTHER AREA OVER SOUTH TEXAS. ALTHOUGH RAINFALL TOTALS WILL BE
LESS THAN PREVIOUS DAYS IN SOUTH TEXAS, SUNDAY'S THREAT REMAINS
DUE TO HIGH SOIL MOISTURE AND STREAM LEVELS FROM RECENT SOAKING
RAINS. ANY RAIN THAT OCCURS IN THIS AREA WILL LIKELY RUNOFF. A
SLOW MOVING COMPLEX OF SHOWERS AND THUNDERSTORMS WILL SPREAD
ACROSS THE COLORADO-OKLAHOMA-TEXAS REGION ON SUNDAY MORNING
BENEATH AN AREA OF RETROGRADING UPPER-LEVEL ENERGY.
A CLOSED LOW OVER THE NORTHERN PLAINS WILL OPEN AND PHASE WITH A
DESCENDING UPPER-LEVEL TROUGH FROM CANADA. THIS WILL SEND A STRONG
COLD FRONT DOWN THROUGH THE NORTHEAST, OHIO/TENNESSEE VALLEYS AND
MID-ATLANTIC REGIONS LATE THIS WEEKEND. SCATTERED SHOWERS AND
THUNDERSTORMS WILL DEVELOP ALONG THIS BOUNDARY WITH SOME
POTENTIALLY TURNING SEVERE IN THE MIDWEST AND TENNESSEE VALLEY.
COOLER TEMPERATURES WILL FOLLOW ON THE BACKSIDE OF THE COLD FRONT
WITH TEMPERATURE DEPARTURES OF 10-20 DEGREES BELOW AVERAGE
POSSIBLE ON SUNDAY AND MONDAY. MORE ANOMALOUSLY COOL TEMPERATURES
WILL BE FELT ACROSS THE GREAT PLAINS WITH SOME 15-25 DEGREE BELOW
NORMAL ANOMALIES LIKELY IN THE WESTERN PARTS OF THE SOUTHERN
PLAINS. ELSEWHERE, VERY WARM TEMPERATURES WILL EXPAND ACROSS THE
WEST. TEMPERATURES IN THE PACIFIC NORTHWEST WILL EXPERIENCE HIGHS
IN THE 80S AND 90S, WHICH WILL REPRESENT 20-30+ DEGREE ANOMALIES.
MANY PARTS OF THE COASTAL PACIFIC NORTHWEST WILL TIE OR BREAK
TEMPERATURE RECORDS THIS WEEKEND. THIS WARMTH WILL SPREAD INTO THE
ROCKIES AND PLAINS BY EARLY NEXT WEEK.
KEBEDE
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