917
FXUS01 KWBC 182012
PMDSPD
SHORT RANGE FORECAST DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
311 PM EST MON NOV 18 2024
VALID 00Z TUE NOV 19 2024 - 00Z THU NOV 21 2024
...A STORM SYSTEM OVER THE CENTRAL U.S. TODAY WILL CREATE CHANCES
FOR SEVERE THUNDERSTORMS, AND GUSTY WINDS ALONG THE GULF COAST...
...HEAVY RAIN AND FLASH FLOODING POTENTIAL EXISTS THROUGHOUT THE
CENTRAL AND EASTERN GULF COAST OVER THE NEXT FEW DAYS...
...POWERFUL PACIFIC LOW PRESSURE SYSTEM TO IMPACT THE NORTHWEST
WITH HIGH WINDS AND HEAVY MOUNTAIN SNOW, WHILE AN ATMOSPHERIC
RIVER TAKES AIM AT NORTHERN CALIFORNIA BY WEDNESDAY...
AN AMPLIFIED WEATHER PATTERN AND TWO SEPARATE STRONG STORM SYSTEMS
WILL IMPACT THE NATION DURING THE FIRST HALF OF THIS WEEK. FIRST,
A DEEP LOW PRESSURE SYSTEM IS EJECTING NORTHEASTWARD ACROSS THE
PLAINS. MODERATE TO HEAVY RAIN AND GUSTY WINDS WILL OCCUR ACROSS
THE PLAINS FOR THE REMAINDER OF MONDAY. THE STORM PREDICTION
CENTER HAS MUCH OF THE CENTRAL PLAINS UNDER A MARGINAL RISK FOR
SEVERE THUNDERSTORMS AS AN ISOLATED STRONG WIND GUST OR SPIN-UP
TORNADO REMAIN POSSIBLE. THE SOUTH-CENTRAL GULF COAST HAS A HIGHER
SEVERE WEATHER THREAT BECAUSE OF MORE FAVORABLE PARAMETERS SUCH AS
ABUNDANT MOISTURE AND INSTABILITY; A SLIGHT RISK FOR SEVERE
WEATHER IS ACTIVE AND THREATS INCLUDE STRONG WINDS AND A COUPLE OF
TORNADOES. THE SEVERE WEATHER THREAT WILL SHIFT EASTWARD AND LOWER
TO A MARGINAL RISK, BUT MUCH OF THE EASTERN TO CENTRAL GULF COAST
MAY HAVE CONDITIONS TO STILL SUPPORT A STRONG WIND GUST OR A
TORNADO OR TWO.
NOW FOR THE FLOODING THREAT WITH THIS SYSTEM, THE HIGHEST RISK
AREAS WILL BE OVER LOUISIANA THROUGH MONDAY AND THE CENTRAL AND
EASTERN GULF COAST, INCLUDING THE FLORIDA PANHANDLE, ON TUESDAY.
THESE REGIONS ARE UNDER A SLIGHT RISK FOR EXCESSIVE RAINFALL AS
HIGH PRECIPITABLE WATER, INSTABILITY, AND POSSIBLE TRAINING OF
STORMS MAY YIELD 2-3 INCHES OF RAINFALL WITH THE RIGHT SET-UP.
SCATTERED FLASH FLOODS ARE MOST LIKELY THROUGHOUT LOW-LYING AND
URBAN REGIONS.
THE SECOND NOTABLE WEATHER SYSTEM WILL BE THE STRONG AREA OF LOW
PRESSURE ACROSS THE PACIFIC NORTHWEST. THE WEATHER PREDICTION
CENTER HAS THE REGION FROM THE PACIFIC NORTHWEST TO NORTHERN
CALIFORNIA UNDER A MARGINAL EXCESSIVE RAINFALL OUTLOOK ON TUESDAY
AS A BAND OF HEAVY RAIN MOVES IN ALONG A COLD FRONT ENTERING THE
REGION. ON WEDNESDAY, THE FLOODING THREAT GREATLY INCREASES; A
MODERATE RISK FOR EXCESSIVE RAINFALL IS IN EFFECT AS FLOODING IS
LIKELY. 6-8 INCHES OF RAINFALL COULD FALL ALONE ON WEDNESDAY AS A
STRONG FLUX OF MOISTURE FROM THE PACIFIC TRAINS OVER THE REGION
DUE TO A NEARLY STATIONARY AREA OF STRONG LOW PRESSURE OUT IN THE
PACIFIC. AREAS IN TERRAIN MAY MAXIMIZE QPF, SOME OF WHICH MAY BE
IN THE FROZEN VARIETY AS MOUNTAIN RANGES IN THE NORTHERN ROCKIES,
NORTHERN CALIFORNIA, AND THE CASCADES IN OREGON AND WASHINGTON
COULD SEE FEET OF HEAVY,WET SNOW. THIS SNOW MAY BE IMPACTFUL FOR
HAZARDS. THE WINTER STORM SEVERITY INDEX HAS SOME RANGES IN THE
MAJOR TO EXTREME IMPACTS, WITH POWER OUTAGES AND DOWNED TREES SOME
OF THE SPECIFIC HAZARDS. ANOTHER NOTABLE THREAT WITH THE SYSTEM IS
THE STRONG WINDS ASSOCIATED WITH A DEEPENING AREA OF LOW PRESSURE.
MANY COASTAL REGIONS ARE UNDER A STORM WARNING FOR WIND GUSTS OVER
70 MPH AND POSSIBLE COASTAL FLOODING HAZARDS.
AS FOR THE REST OF THE COUNTRY OUTSIDE THESE TWO DYNAMIC SYSTEMS,
THE EAST COAST SHOULD BE RELATIVELY WARM WITH TEMPERATURES ABOUT
10-15 DEGREES ABOVE AVERAGE INTO WEDNESDAY. HIGHS GO FROM THE 50S
IN NEW ENGLAND, THE 60S AND 70S ACROSS THE MID-ATLANTIC, AND A
PROGRESSIVELY WARMER AND MORE HUMID AIRMASS IN THE SOUTHEAST AND
FLORIDA WITH HIGHS IN THE 70S AND 80S. OUT WEST, A REINFORCING
SHOT OF COLD AIR WILL FUNNEL IN BEHIND A COLD FRONT CLEARING THE
ROCKIES THIS AFTERNOON. HIGH TEMPERATURES WILL BE IN THE 30S AND
40S FROM THE NORTHERN PLAINS TO MUCH OF THE INTERMOUNTAIN WEST AND
LOWS WILL FALL TO THE SINGLE DIGITS IN THIS COLD AIR MASS IN THE
TYPICAL COLD SPOTS. THE DESERT SOUTHWEST AND SOUTHERN CALIFORNIA
WILL MUCH WARMER THAN THEIR WESTERN NEIGHBORS, AS HIGHS SHOULD
STILL MANAGE TO BE QUITE MILD IN THE 70S.
WILDER
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