Prognostic Meteorological Discussion
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FXUS01 KWBC 190751
PMDSPD

SHORT RANGE FORECAST DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
350 AM EDT THU OCT 19 2017

VALID 12Z THU OCT 19 2017 - 12Z SAT OCT 21 2017

...HEAVY RAINFALL EXPECTED ACROSS THE PACIFIC NORTHWEST...

...SNOW EXPECTED ACROSS THE CASCADES AND NORTHERN ROCKIES...

...SCATTERED THUNDERSTORMS FOR FLORIDA, THE SOUTHWEST, AND THE
TEXAS COAST...

...HEAVY RAINFALL AND AN ENHANCED RISK OF SEVERE THUNDERSTORMS ARE
POSSIBLE FOR THE SOUTHERN PLAINS TO THE MIDDLE MISSISSIPPI
VALLEY...


AS A COLD FRONT DIVES ACROSS THE PACIFIC NORTHWEST TODAY,
PRECIPITATION WILL INCREASE THROUGHOUT THAT REGION AND INTO THE
NORTHERN ROCKIES. HEAVY RAINFALL IS EXPECTED TO OCCUR IN WESTERN
WASHINGTON AND NORTHWESTERN OREGON WHERE THERE IS A MARGINAL RISK
OF FLASH FLOODING. IN ADDITION, HIGHER ELEVATION SNOW IS EXPECTED
FOR THE CASCADES IN ADDITION TO THE NORTHERN PORTIONS OF THE
SIERRA NEVADA MOUNTAIN RANGE. AS THE FRONT PUSHES ACROSS
INTERMOUNTAIN WEST ON FRIDAY, PRECIPITATION WILL FOLLOW SUIT--WITH
SNOW TAMPING UP ALONG THE NORTHERN ROCKIES. ONSHORE FLOW WILL KEEP
RAINFALL AND HIGHER ELEVATION SNOW IN THE PACIFIC NORTHWEST ON
FRIDAY. BY SATURDAY, ANOTHER FRONTAL SYSTEM WILL BEGIN APPROACHING
THE PACIFIC NORTHWEST, ENSURING ADDITIONAL HEAVY RAINFALL AND
HIGHER ELEVATION SNOW ONCE AGAIN FOR THE REGION.

A SLOW MOVING FRONT NEAR SOUTH FLORIDA WILL LINGER OVER THE NEXT
FEW DAYS.  WITH PLENTY OF MOISTURE IN PLACE FROM EASTERLY FLOW,
THIS FRONT WILL ACT AS A FOCAL POINT FOR SHOWERS AND THUNDERSTORMS
ESPECIALLY IN THE AFTERNOON AND EVENING. THE HEAVIEST ACTIVITY IS
EXPECTED ALONG THE ATLANTIC COAST AND SOUTH FLORIDA. AS AN UPPER
LEVEL TROUGH APPROACHES THE SOUTHWEST AND SOUTHERN PLAINS, THIS
WILL FIRE OFF CONVECTION ACROSS NEW MEXICO AND WEST TEXAS. IN
ADDITION, SOUTHEASTERLY FLOW AHEAD OF AN APPROACHING UPPER LEVEL
TROUGH ALONG THE DEEP SOUTH TEXAS COASTLINE WILL BRING SHOWERS AND
THUNDERSTORMS TO THE AREA TODAY. ON FRIDAY AND SATURDAY, THE
MOISTURE AXIS WILL SHIFT TO THE MIDDLE AND UPPER TEXAS
COASTLINES--BRINGING SCATTERED SHOWERS AND THUNDERSTORMS TO THESE
AREAS.

MEANWHILE, THE STRONG COLD FRONT THAT PUSHES ACROSS THE
INTERMOUNTAIN WEST IS EXPECTED TO SWEEP OVER THE PLAINS ON
SATURDAY. MOISTURE FROM THE GULF OF MEXICO WILL BE ON TAP AND WITH
INSTABILITY IN PLACE--A LINE OF SHOWERS AND THUNDERSTORMS ARE
EXPECTED TO DEVELOP IN THE PLAINS. HEAVY RAINFALL IS POSSIBLE FROM
THE RED RIVER VALLEY TO THE MIDDLE MISSISSIPPI VALLEY--WHERE THERE
IS A SLIGHT RISK OF FLASH FLOODING. IN ADDITION, THERE IS AN
ENHANCED RISK OF SEVERE THUNDERSTORMS FOR NORTH TEXAS AND
CENTRAL/EASTERN OKLAHOMA. PLEASE SEE THE STORM PREDICTION CENTER
FOR MORE INFORMATION ON THE SEVERE WEATHER IMPACTS WITH THIS
SYSTEM.

REINHART



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