394  
FXUS01 KWBC 271959  
PMDSPD  
 
SHORT RANGE FORECAST DISCUSSION  
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD  
258 PM EST TUE FEB 27 2018  
 
VALID 00Z WED FEB 28 2018 - 00Z FRI MAR 02 2018  
 
...INCREASING CHANCES FOR FLOODING ISSUES FROM THE ARKLATEX  
EASTWARD INTO THE MID-SOUTH...  
 
...HEAVY RAIN AND SNOW EXPECTED FROM CENTRAL CALIFORNIA UP INTO  
THE PACIFIC NORTHWEST...  
 
...RATHER LOW SNOW LEVELS COULD BRING WINTRY PRECIPITATION CLOSE  
TO THE NORTHERN CALIFORNIA COAST...  
 
WITH A BROAD UPPER RIDGE MAINTAINING ITS DOMINANCE OVER THE  
EASTERN PACIFIC WATERS, MULTIPLE SYSTEMS ARE PRIMED TO SLIDE DOWN  
THE WEST COAST WITH EVENTUAL TRANSITION TOWARD THE CENTER OF THE  
COUNTRY. MEANWHILE, THE NORTHERN BRANCH OF THE JET STREAM WILL  
ALSO BE QUITE ACTIVE AS A SERIES OF SMALLER-SCALE IMPULSES COULD  
BE IMPETUS FOR PRECIPITATION, PARTICULARLY GIVEN ANY INTERACTION  
WITH MID-LATITUDE FEATURES.  
 
AS A ROBUST UPPER LOW EJECTS OUT OF SOUTHERN CALIFORNIA, MOISTURE  
RETURN WILL BE ON THE INCREASE ACROSS THE SOUTHERN PLAINS  
RESULTING IN A WELL DEFINED DRY LINE ACROSS THE REGION. WEST OF  
THIS BOUNDARY, DRY AND WINDY CONDITIONS SHOULD PREVAIL, THUS  
ENHANCING THE THREAT FOR WILDFIRES. DURING THE NEXT COUPLE OF  
DAYS, AN AREA STRETCHING FROM SOUTHEASTERN ARIZONA OUT TOWARD THE  
SOUTHERN HIGH PLAINS ARE IN ELEVATED TO CRITICAL RISKS FOR  
WILDFIRES PER THE STORM PREDICTION CENTER OUTLOOK. ON THE OTHER  
SIDE OF THE SPECTRUM, HEAVY RAINFALL WILL SPREAD NORTH OF THE  
ADVANCING WARM FRONT WITH THE ACTIVITY CONCENTRATING FROM THE  
DALLAS/FORT WORTH METRO AREA EASTWARD THROUGH MUCH OF ARKANSAS AND  
INTO VAST SECTIONS OF THE MID-SOUTH. BASED ON THE LATEST FORECAST,  
SEVERAL INCHES OF RAINFALL ARE POSSIBLE FROM ROUGHLY LITTLE ROCK,  
ARKANSAS EASTWARD INTO TENNESSEE, GENERALLY JUST SOUTH OF  
INTERSTATE 40. GIVEN RECENT HEAVY RAINFALL OVER THE REGION,  
FLOODING AND FLASH FLOODING WILL BE LIKELY WITHIN ANY TRAINING  
BANDS OF CONVECTION OR AREAS WHERE STORMS TEND TO REPEAT OVER THE  
SAME AREAS. SOILS REMAIN SATURATED SO IT WILL NOT TAKE A  
SIGNIFICANT AMOUNT OF PRECIPITATION TO CAUSE HYDROLOGIC ISSUES.  
 
WHILE THIS SYSTEM DOES ACCELERATE AND BECOME MORE STRETCHED OUT IN  
NATURE, THERE MAY BE SOME INTERACTION WITH A TROUGH DIPPING DOWN  
OVER THE GREAT LAKES. A GREAT DEAL OF UNCERTAINTY EXISTS WITH THIS  
SCENARIO BUT IT IS WORTH MONITORING GIVEN THE FEW WAVES OF LOW  
PRESSURE TO TRACK OVER THE OHIO VALLEY AND ACROSS THE COASTAL  
MID-ATLANTIC. OVERALL, THE NUMBER OF DISTURBANCES TRAVERSING THE  
UPPER MIDWEST INTO NEW ENGLAND WILL KEEP CONDITIONS UNSETTLED  
THROUGHOUT THE WEEK. SEVERAL INCHES OF SNOW ARE POSSIBLE ACROSS  
NORTHERN MAINE WHILE A SEPARATE AXIS OF SNOW CAN BE FOUND BACK  
OVER THE UPPER GREAT LAKES, ALBEIT WITH LIGHTER AMOUNTS.  
 
ON THE HEELS OF THE FIRST CLOSED LOW EXITING THE SOUTHWESTERN  
STATES, AN EVEN MORE EXPANSIVE CIRCULATION DIVES DOWN FROM THE  
GULF OF ALASKA. STRONG LIFT ACCOMPANYING THIS SYSTEM WILL DRIVE  
ABUNDANT PRECIPITATION ANYWHERE FROM CENTRAL CALIFORNIA NORTHWARD  
INTO BRITISH COLUMBIA. AS USUAL, THE LOCAL TERRAIN CAN EXPECT  
HEAVIER AMOUNTS GIVEN FAVORABLE OROGRAPHIC LIFT. MORE  
SPECIFICALLY, THE CURRENT FORECAST SUGGESTS 1 TO 2 FEET OF SNOW  
ACROSS THE SHASTA, TRINITY, AND SISKIYOU RANGES OF EXTREME  
NORTHERN CALIFORNIA AS WELL AS OVER THE OLYMPICS, CASCADES, AND  
BLUE MOUNTAINS. EVEN HIGHER AMOUNTS ARE POSSIBLE ACROSS THE  
SIERRA NEVADA RANGES WITH UP TO 3 FEET IN THE FORECAST. WITH SNOW  
LEVELS LIKELY DROPPING TO AROUND 2000 FEET, SOME OF THE  
ACCUMULATIONS COULD EASILY EDGE TOWARD THE COASTLINE.  
 
RUBIN-OSTER  
 
GRAPHICS AVAILABLE AT  
WWW.WPC.NCEP.NOAA.GOV/BASICWX/BASICWX_NDFD.PHP  

 
 
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