622
FXUS01 KWBC 181828
PMDSPD
SHORT RANGE FORECAST DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
227 PM EDT TUE APR 18 2023
VALID 00Z WED APR 19 2023 - 00Z FRI APR 21 2023
...SNOW OVER THE NORTHERN ROCKIES ON TUESDAY AND WEDNESDAY;
MODERATE SNOW OVER PARTS OF THE NORTHERN PLAINS ON WEDNESDAY...
...CRITICAL FIRE WEATHER WILL CONTINUE THROUGH THURSDAY ACROSS THE
SOUTHERN HIGH PLAINS AS WELL AS ACROSS THE MID-ATLANTIC TUESDAY...
...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS OVER PARTS OF
THE CENTRAL/SOUTHERN PLAINS INTO THE MIDDLE MISSISSIPPI VALLEY ON
WEDNESDAY...
...THERE IS A MARGINAL RISK OF EXCESSIVE RAINFALL OVER PARTS OF
THE CENTRAL PLAINS, LOWER MISSOURI AND UPPER MISSISSIPPI VALLEYS
ON WEDNESDAY...
FOR THE REMAINDER OF TUESDAY, AN UPPER-LEVEL WAVE WILL CONTINUE TO
TRACK THROUGH THE NORTHERN INTERMOUNTAIN WEST SUPPORTING SOME
MODERATE SNOWFALL ACROSS THE NORTHERN ROCKIES THIS EVENING.
CONCURRENTLY, A SURFACE LOW NEAR THE BLACK HILLS OF SD AND
PORTIONS OF E MT/WY WILL START TO STRENGTHEN AND MERGE WITH THE
ASSOCIATED PACIFIC COLD FRONT, LIFTING A WARM FRONT NORTHWARD
ACROSS THE CENTRAL PLAINS SPARKING THE POTENTIAL FOR A FEW
ISOLATED SEVERE THUNDERSTORMS. THE STORM PREDICATION CENTER (SPC)
HAS A BROAD MARGINAL RISK IN THE VICINITY OF THE LOW AND SOUTHWARD
INTO THE CENTRAL HIGH PLAINS JUST AHEAD OF A STRENGTHENING DRY
LINE. FURTHER SOUTH, THE STRENGTHENING WINDS AND VERY DRY GROUND
CONDITIONS WILL CONTINUE TO SUPPORT A BROAD CRITICAL FIRE WEATHER
AREA ISSUED BY SPC, WITH A LARGE AREA OF NEW MEXICO, EASTERN
COLORADO, WESTERN NEBRASKA, WESTERN KANSAS AND PARTS OF THE OK/TX
PANHANDLES ALREADY UNDER RED FLAG WARNINGS. THIS RISK WILL
CONTINUE AS THE STRONG PACIFIC FLOW OVER-TOPPING THE CENTRAL
ROCKIES WILL KEEP WINDS AND RELATIVE HUMIDITY LOW THROUGH WED INTO
THURSDAY AS WELL.
INTO THE OVERNIGHT PERIOD (TUES INTO WEDNESDAY), THE SURFACE LOW
WILL CONTINUE TO LIFT NORTH, STRENGTHEN AND HAVE THE POTENTIAL FOR
PRODUCING MODERATE TO OCCASIONALLY HEAVY SNOW FALL ACROSS FAR
EASTERN MT, AND WESTERN/NORTHWESTERN NORTH DAKOTA, PEAKING
WEDNESDAY MORNING, BUT LIKELY TO CONTINUE THROUGHOUT THE REMAINDER
OF THE DAY INTO EARLY THURSDAY MORNING.
AS THE MAIN UPPER-LEVEL ENERGY EMERGES INTO THE NORTHERN PLAINS ON
WED, THE RISK FOR SEVERE WEATHER INCREASES IN COVERAGE/INTENSITY,
AS THE SPC HAS ISSUED A SLIGHT RISK ALONG/AHEAD OF THE COLD FRONT
AND DRY LINE FROM EASTERN NEBRASKA INTO IOWA AND SOUTHWARD ACROSS
CENTRAL/EASTERN KANSAS INTO WESTERN OKLAHOMA. LARGE HAIL AND HIGH
WINDS ARE THE GREATEST POTENTIAL, THOUGH AN ISOLATED TORNADO OR
TWO REMAIN POSSIBLE, WITH HIGHEST POTENTIAL ACROSS CENTRAL KANSAS.
AS THE THUNDERSTORMS EXPAND IN COVERAGE INTO THE EARLY OVERNIGHT
PERIOD, THUNDERSTORMS WILL POSE A RISK OF EXCESSIVE RAINFALL/FLASH
FLOODING MAINLY NORTH AND EAST OF THE SPC SLIGHT RISK, GIVEN AREAS
OF IOWA, SOUTHEAST MINNESOTA, WISCONSIN SOILS MORE SATURATED AND
HAVE SEEN RECENT SNOW MELT. AS SUCH, THE WEATHER PREDICTION
CENTER (WPC) HAS ISSUED A BROAD MARGINAL RISK TO ACCOUNT FOR HEAVY
RAINFALL OVER THESE SATURATED AREAS RESULTING IN ISOLATED TO
WIDELY SCATTERED FLASH FLOODING POTENTIAL INTO THURSDAY MORNING.
ELSEWHERE, A VERY BROAD LARGE SCALE LOW DOMINATES SOUTHEAST CANADA
RESULTING IN LARGE AREA OF INCREASED CLOUD COVER ACROSS THE
NORTHEAST, KEEPING TEMPERATURES AT OR BELOW AVERAGE TODAY INTO
TOMORROW. SOUTH OF THE CLOUD AREA IN THE MID-ATLANTIC, CLEARER
SKIES AND DRIER AIR (ALONG WITH DRIER THAN NORMAL
SOILS/VEGETATION) WILL SEE INCREASED TEMPERATURES IN THE 70S AND
80S INTO WEDNESDAY. THE COMBINATION HAS RESULTED IN INCREASED
FIRE WEATHER CONCERNS, WITH THE SPC ISSUING A CRITICAL FIRE AREA
ACROSS THE PIEDMONT OF VIRGINIA WITH A SURROUNDING ELEVATED RISK
OVER THE REMAINDER OF THE STATE AND PORTIONS OF ADJACENT MARYLAND,
WEST VIRGINIA, DELAWARE AND FAR NORTHEAST NORTH CAROLINA. RED
FLAG WARNINGS ARE UP FOR MUCH OF THE ELEVATED AREA FOR TODAY,
TUESDAY.
GALLINA
GRAPHICS AVAILABLE AT
HTTPS://WWW.WPC.NCEP.NOAA.GOV/BASICWX/BASICWX_NDFD.PHP
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