Prognostic Meteorological Discussion
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FXUS01 KWBC 120735
PMDSPD

SHORT RANGE FORECAST DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
334 AM EDT SAT JUL 12 2014

VALID 12Z SAT JUL 12 2014 - 12Z MON JUL 14 2014

...A VERY ACTIVE WEATHER PATTERN FOR MANY AREAS OF THE US WITH
HEAVY RAIN AND STRONG THUNDERSTORMS AFFECTING AREAS OF THE ROCKY
MOUNTAINS, THE CENTRAL PLAINS INTO THE MIDWEST AND OHIO VALLEY...

...HOT WEATHER WILL BE BUILDING ACROSS THE FAR WEST AS
TEMPERATURES CLIMB PAST 100 ACROSS INTERIOR CALIFORNIA AND INTO
THE 90S INTO WESTERN WASHINGTON...

...ON THE FLIP SIDE OF THE COIN, UNUSUALLY COOL AIR FOR JULY WILL
BEGIN PUSHING INTO THE NORTHERN PLAINS BY SATURDAY NIGHT.  BY LATE
MONDAY, THE COOLEST AIR IN NORTH AMERICA WILL BE LOCATED OVER THE
UPPER MIDWEST...

A MONSOONAL FLOW PATTERN OVER THE WESTERN US WILL BRING MOISTURE
NORTHWARD ACROSS THE DESERT SOUTHWEST, GREAT BASIN AND CENTRAL AND
SOUTHERN ROCKIES.  WITH AFTERNOON HEATING, WIDESPREAD BUT
SCATTERED THUNDERSTORMS WILL DEVELOP AGAIN OVER THIS REGION
ESPECIALLY OVER THE HIGH TERRAIN, WHERE THE THREAT FOR FLASH
FLOODING AND FIRE WEATHER DUE TO LIGHTNING STRIKES WILL PERSIST
FOR THE NEXT SEVERAL DAYS.

WHILE SOME OF THE MONSOONAL MOISTURE WILL EVEN WORK ITS WAY INTO
THE PACIFIC NORTHWEST, TEMPERATURES WILL BE RISING OVER THE NEXT
SEVERAL DAYS WITH TEMPERATURES EXCEEDING 100 DEGREES OVER NORTHERN
INTERIOR CALIFORNIA, 90S INTO PORTLAND AND NEAR 90 DEGREES IN
SEATTLE.

AS THE HEAT BUILDS IN THE WEST, COOLER AIR MORE TYPICAL OF
SEPTEMBER OR OCTOBER WILL MAKE ITS WAY SOUTHWARD OVER CANADA,
REACHING THE NORTHERN PLAINS ON SATURDAY NIGHT AND REACHING ACROSS
MUCH OF THE CENTRAL AND NORTHERN PLAINS, THE MIDDLE AND UPPER
MISSISSIPPI VALLEY AND INTO THE MIDWEST BY MONDAY NIGHT.  WITH
COLD AIR ALOFT, INSTABILITY SHOWERS AND THUNDERSHOWERS MAY ALSO
ACCOMPANY THE CHILLY AIRMASS THAT WILL DROP TEMPERATURES TO AUTUMN
LEVELS EVEN DURING THE DAY ON MONDAY.

IN BETWEEN THE ADVANCING COOLER AIR AND A POOL OF STAGNANT HOT AIR
ACROSS THE SOUTHERN PLAINS, THE MONSOONAL MOISTURE MOVING
NORTHWARD ACROSS THE ROCKIES ACCOMPANIED BY WEAK UPPER LEVEL
DISTURBANCES WILL GENERATE PULSES OF HEAVY RAIN AND THUNDERSTORMS
FROM THE CENTRAL PLAINS EASTWARD ACROSS THE MID MISSISSIPPI VALLEY
ON MIDWEST ON SATURDAY.  WITH THE COLD FRONT ADVANCING EASTWARD,
THE THUNDERSTORMS WILL ALSO MOVE EASTWARD, AFFECTING THE OHIO
VALLEY AND NORTHEAST ON SUNDAY.  AS THE MAIN CORE OF THE COOLER
AIR DROPS INTO THE US ON MONDAY, A WIDESPREAD OUTBREAK OF
THUNDERSTORMS AND POSSIBLE SEVERE WEATHER MAY AFFECT PARTS OF THE
MIDWEST AND EAST ON MONDAY INTO TUESDAY.

KOCIN


GRAPHICS AVAILABLE AT WWW.WPC.NCEP.NOAA.GOV
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