680
FXUS01 KWBC 201946
PMDSPD
SHORT RANGE FORECAST DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
345 PM EDT THU APR 20 2023
VALID 00Z FRI APR 21 2023 - 00Z SUN APR 23 2023
...SHOWERS AND THUNDERSTORMS CONTINUE EASTWARD ALONG A COLD FRONT
FROM THE MISSISSIPPI VALLEY TO THE EAST COAST WITH ISOLATED FLASH
FLOODING AND SEVERE WEATHER POSSIBLE...
...MODERATE TO LOCALLY HEAVY SNOW WILL CONTINUE INTO THE DAY
FRIDAY FOR PORTIONS OF THE NORTHERN PLAINS/UPPER MIDWEST...
...PRECIPITATION CHANCES INCREASE FOR THE NORTHERN/CENTRAL ROCKIES
AND PACIFIC NORTHWEST FRIDAY; TRANQUIL CONDITIONS FOR CALIFORNIA
AND THE SOUTHWEST...
A FRONTAL SYSTEM PUSHING EASTWARD BENEATH A DEEPENING UPPER-LEVEL
LOW WILL CONTINUE TO BRING WIDESPREAD SHOWERS AND THUNDERSTORMS
WITH THE RISK OF FLASH FLOODING AND SEVERE WEATHER FROM PORTIONS
OF THE OHIO/MISSISSIPPI VALLEYS FRIDAY TO THE EAST COAST ON
SATURDAY. THERE IS A SIGHT RISK OF EXCESSIVE RAINFALL (LEVEL 2/4)
FOR PORTIONS OF THE LOWER MISSISSIPPI AND TENNESSEE VALLEYS FRIDAY
WHERE ACCESS TO DEEPER GULF MOISTURE WILL PROMOTE LOCALLY HEAVIER
RAIN RATES AND 2-3"+ RAINFALL TOTALS. THE SLOW PROGRESSION OF THE
COLD FRONT WILL LEAD TO SOME REPEATED ROUNDS OF STORMS OVER AREAS
THAT SAW RAIN THURSDAY, LEADING TO THE RISK FOR SOME SCATTERED
INSTANCES OF FLASH FLOODING. MODERATE TO LOCALLY HEAVY RAINFALL
WILL MOVE EASTWARD ON SATURDAY THROUGH THE APPALACHIANS AND TO THE
EAST COAST, THOUGH THE RISK FOR ANY FLOODING SHOULD DECREASE AS
THE FRONT SPEEDS UP AND OVERAL TOTALS TREND LOWER. HOWEVER, THE
STORM PREDICTION CENTER HAS ISSUED A SLIGHT RISK (LEVEL 2/5) OF
SEVERE WEATHER FOR PORTIONS OF THE COASTAL CAROLINAS AS MODERATE
CAPE AND DEEP-LAYER SHEAR AHEAD OF THE COLD FRONT WILL LEAD TO A
LINE OF STORMS WITH THE POTENTIAL TO PRODUCE SEVERE HAIL AND
DAMAGING WINDS. HIGH TEMPERATURES WILL GENERALLY REMAIN IN THE 80S
FOR MUCH OF THE EAST FRIDAY, WITH SOME RECORD-TYING/BREAKING HIGHS
IN THE UPPER 80S TO LOW 90S POSSIBLE FOR THE MID-ATLANTIC.
INCREASED PRECIPITATION CHANCES AS THE COLD FRONT APPROACHES ON
SATURDAY WILL DROP TEMPERATURES INTO THE 70S FOR THE MID-ATLANTIC.
NEW ENGLAND WILL REMAIN COOLER ON THE NORTH SIDE OF A STATIONARY
FRONT WITH HIGHS IN THE 50S AND 60S.
MODERATE TO LOCALLY HEAVY SNOW WILL CONTINUE THURSDAY EVENING INTO
EARLY FRIDAY OVER PORTIONS OF THE NORTHERN PLAINS/UPPER MIDWEST ON
THE NORTHWEST SIDE OF THE LOW PRESSURE/FRONTAL SYSTEM. THE SNOW
SHOULD BEGIN TO TAPER OFF BY LATER FRIDAY EVENING/EARLY SATURDAY,
WITH STORM TOTAL SNOWFALL GENERALLY BETWEEN 3-6", LOCALLY AS HIGH
AS A FOOT. GUSTY WINDS WILL ALSO LEAD TO AREAS OF BLOWING SNOW AND
DANGEROUS TRAVEL CONDITIONS. HIGH TEMPERATURES WILL REMAIN QUITE
CHILLY AND MUCH BELOW AVERAGE BEHIND THE COLD FRONT AND UNDER THE
INFLUENCE OF THE UPPER-LEVEL LOW, WITH HIGHS IN THE 30S AND 40S
FOR THE NORTHERN PLAINS/UPPER MIDWEST FRIDAY SPREADING INTO THE
GREAT LAKES AND PORTIONS OF THE UPPER/MIDDLE MISSISSIPPI VALLEY ON
SATURDAY. HIGHS FROM THE CENTRAL PLAINS TO THE LOWER OHIO VALLEY
WILL DROP FROM THE 60S FRIDAY INTO THE 50S ON SATURDAY.
FURTHER SOUTH, ONGOING SHOWERS AND THUNDERSTORMS IN EASTERN TEXAS
WILL END BY FRIDAY EVENING AS THE COLD FRONT PUSHES OFF THE GULF
COAST. CONDITIONS ACROSS THE SOUTHERN PLAINS WILL TURN COOLER WITH
HIGHS GENERALLY IN THE 60S AND 70S FRIDAY AND SATURDAY OUTSIDE OF
THE RIO GRANDE VALLEY. MORNING LOWS FOR PORTIONS OF THE TEXAS
PANHANDLE AND OKLAHOMA WILL DIP AS LOW AS THE UPPER 30S. GUSTY
WINDS MIXING DOWN OVER THE SOUTHERN HIGH PLAINS COMBINED WITH LOW
RELATIVE HUMIDITY AND DRY ANTECEDENT CONDITIONS HAVE PROMPTED A
CRITICAL RISK FOR FIRE WEATHER (LEVEL 2/3) FROM THE STORM
PREDICTION CENTER FRIDAY.
UPPER-LEVEL SHORTWAVE ENERGY PASSING OVER THE INTERMOUNTAIN WEST
WILL TRIGGER SNOW SHOWERS FOR PORTIONS OF THE NORTHERN AND CENTRAL
ROCKIES FRIDAY. SOME LOCALLY HEAVY ACCUMULATING SNOW WILL BE
POSSIBLE FOR HIGHER MOUNTAIN ELEVATIONS, PARTICULARLY IN THE
CENTRAL ROCKIES. A PACIFIC STORM SYSTEM WILL APPROACH THE PACIFIC
NORTHWEST LATER THURSDAY EVENING INCREASING CHANCES FOR LIGHT TO
MODERATE LOWER ELEVATION COASTAL/VALLEY RAIN AND HIGHER ELEVATION
SNOW HERE AS WELL. HIGHS WILL REMAIN COOL FOR THE NORTHERN/CENTRAL
ROCKIES FOLLOWING THE PASSAGE OF A COLD FRONT AND ON THE WESTERN
EDGE OF THE EXPANSIVE UPPER-LEVEL LOW, WITH HIGHS GENERALLY IN THE
40S AND 50S. AN UPPER-LEVEL RIDGE BUILDING OFF THE PACIFIC COAST
WILL LEAD TO TRANQUIL CONDITIONS AND NEAR-AVERAGE TEMPERATURES FOR
CALIFORNIA, THE SOUTHERN GREAT BASIN, AND THE DESERT SOUTHWEST.
HIGHS FRIDAY AND SATURDAY WILL RANGE BETWEEN THE 70S AND 80S FOR
MOST OF CALIFORNIA AND THE GREAT BASIN WITH 90S IN THE DESERT
SOUTHWEST.
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