148  
FXUS02 KWBC 070701  
PMDEPD  
 
EXTENDED FORECAST DISCUSSION  
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD  
200 AM EST MON MAR 07 2022  
 
VALID 12Z THU MAR 10 2022 - 12Z MON MAR 14 2022  
 
...WINTER STORM THREAT FOR PARTS OF THE MIDWEST ON  
THURSDAY-FRIDAY, WITH HEAVY TO EXCESSIVE RAINFALL LIKELY ACROSS  
THE SOUTHEAST...  
   
..OVERVIEW
 
 
A SHORTWAVE DIGGING SOUTH THROUGH THE INTERIOR WEST AS THE MEDIUM  
RANGE PERIOD STARTS THURSDAY WILL AMPLIFY TROUGHING ACROSS THE  
CENTRAL U.S. AND SHIFT EAST WITH TIME, EXITING THE EAST COAST BY  
SUNDAY. THIS WILL PUSH A STRONG ARCTIC BOUNDARY SOUTH ACROSS THE  
PLAINS AND THEN THE EAST AS AN AREA OF LOW PRESSURE DEVELOPS AND  
DEEPENS THROUGH THE MIDWEST AND NORTHEAST FRIDAY AND SATURDAY. A  
SWATH OF SNOW IS EXPECTED TO THE NORTHWEST OF THE SURFACE LOW,  
POTENTIALLY HEAVY RAINFALL ACROSS PARTS OF THE EAST AHEAD OF THE  
FRONT, AND A CHILLY ARCTIC AIRMASS ENGULFING MUCH OF THE CENTRAL  
AND EASTERN U.S. TO FOLLOW. BY EARLY NEXT WEEK, FLOW ACROSS THE  
CONUS SHOULD BECOME A LITTLE MORE ZONAL AS WEAK SYSTEMS MOVE  
THROUGH THE NORTHERN TIER STATES, THOUGH THE NEXT TROUGH MAY  
DEVELOP ACROSS THE CENTRAL U.S. BY NEXT MONDAY.  
 
   
..GUIDANCE EVALUATION/PREDICTABILITY ASSESSMENT
 
 
IN GENERAL, THE MODEL GUIDANCE CONTINUES TO SHOW REASONABLE  
AGREEMENT FOR THE LARGE SCALE PATTERN ACROSS THE CONUS, BUT WITH  
PLENTY OF UNCERTAINTY IN TIMING AND DETAILS OF FEATURES. THE MOST  
IMPACTFUL DIFFERENCES SURROUND THE AMPLIFIED TROUGH INTO THE  
PLAINS AND EAST FRIDAY-SATURDAY. THE 18Z/MAR 6 (AND TODAYS NEW  
00Z) RUN OF THE GFS CONTINUES TO BE QUITE A BIT FASTER WITH TROUGH  
AXIS AND FRONTAL PLACEMENT, ALTHOUGH AN EVER SO SLIGHT SLOWER  
TREND IS NOTED WITH THE LAST FEW RUNS. MEANWHILE, THE 12Z/MAR 6  
ECMWF (WITH SUPPORT FROM ITS ENSEMBLE MEMBERS) WAS THE SLOWEST OF  
THE SOLUTIONS, HOWEVER THE 00Z RUN TODAY DID COME IN A LITTLE  
FASTER. BOTH THE CMC AND UKMET WERE MORE IN THE MIDDLE OF THESE  
TWO CAMPS, AND PROBABLY THE BEST PROXY FOR THE OVERNIGHT MEDIUM  
RANGE PROGS WHICH ARE A HAIR SLOWER THAN PREVIOUS WPC CONTINUITY.  
THE NEXT SHORTWAVE HITS THE PACIFIC NORTHWEST BY SUNDAY, AND  
THERE'S PRETTY GOOD AGREEMENT ON THIS, BUT THE CMC IS A LITTLE  
SLOWER. BEYOND DAY 5, PREFERRED A SOLUTION CLOSER TO THE ENSEMBLE  
MEANS TO HELP MITIGATE THESE LATER PERIOD DIFFERENCES WHICH WILL  
TAKE TIME TO RESOLVE ANYWAYS.  
 
   
..WEATHER HIGHLIGHTS/THREATS
 
 
SHOWERS AND THUNDERSTORMS SHOULD BE ONGOING BY THURSDAY ACROSS THE  
SOUTHEAST AS A FRONTAL BOUNDARY SETTLES OVER THE REGION WITH AMPLE  
MOISTURE AND INSTABILITY PRESENT. THIS BOUNDARY SHOULD FINALLY  
BECOME ABSORBED/PUSH EAST WITH THE STRONG COLD FRONT ON SATURDAY,  
BUT NOT BEFORE SEVERAL DAYS OF WIDESPREAD RAIN. AT LEAST LOCALLY  
HEAVY RAINFALL IS A CONCERN, AND FLOODING/FLASH FLOODING MAY BE A  
THREAT WITH HEAVY DOWNPOURS, ESPECIALLY WHERE MULTIPLE ROUNDS OF  
CONVECTION TRACK OVER THE SAME AREAS DURING THE PERIOD, DESPITE  
THE RELATIVELY DRY ANTECEDENT CONDITIONS. MEANWHILE, LOW PRESSURE  
SPINNING UP IN THE LEE OF THE ROCKIES AND LIFTING INTO THE UPPER  
MIDWEST THURSDAY-FRIDAY BRINGS A WINTER STORM THREAT FROM THE  
CENTRAL PLAINS TO THE UPPER MIDWEST, WITH LESS CERTAIN WINTRY  
IMPACTS INTO THE OHIO VALLEY AND INTERIOR NORTHEAST FRIDAY AND  
SATURDAY. THE ELONGATED UPPER TROUGH SHOULD TAP GULF OF MEXICO  
MOISTURE WITH WIDESPREAD RAIN INTO MUCH OF THE EAST AHEAD OF THE  
COLD FRONT ON FRIDAY. THE NEXT SYSTEM COMING INTO THE NORTHWEST  
NEXT WEEKEND IS LIKELY TO INCREASE RAIN AND MOUNTAIN SNOW CHANCES  
ACROSS THE PACIFIC NORTHWEST AND NORTHERN ROCKIES AS WELL.  
 
ARCTIC SOURCED AIR WILL SPILL INTO THE PLAINS ON THE BACKSIDE OF  
THE FRONT, WITH DAYTIME HIGHS 20-30+ DEGREES BELOW NORMAL AS FAR  
SOUTH AS TEXAS THROUGH FRIDAY. OVERNIGHT LOWS ACROSS THE NORTHERN  
PLAINS AND IN HIGHER ELEVATIONS OF THE ROCKIES ARE LIKELY TO BE  
NEAR OR BELOW ZERO FOR MANY LOCATIONS. AHEAD OF THE COLD FRONT,  
ABOVE NORMAL TEMPERATURES SHOULD SPREAD ACROSS THE EASTERN THIRD  
OF THE COUNTRY THURSDAY AND FRIDAY BEFORE BEING REPLACED BY BELOW  
NORMAL TEMPERATURES NEXT WEEKEND FOLLOWING THE PASSAGE OF THE COLD  
FRONT. MEANWHILE, PARTS OF THE WEST AND CENTRAL U.S. NEXT  
SUNDAY-MONDAY MAY BE MODERATELY ABOVE NORMAL AS UPPER RIDGING  
SLIDES OVERHEAD.  
 
SANTORELLI  
 
ADDITIONAL 3-7 DAY HAZARD INFORMATION CAN BE FOUND ON THE WPC  
MEDIUM RANGE HAZARDS OUTLOOK CHART AT:  
HTTPS://WWW.WPC.NCEP.NOAA.GOV/THREATS/THREATS.PHP  
 
HTTPS://WWW.WPC.NCEP.NOAA.GOV/MEDR/5DAYFCST500_WBG.GIF  
HTTPS://WWW.WPC.NCEP.NOAA.GOV/MEDR/5DAYFCST_WBG_CONUS.GIF  
HTTPS://WWW.WPC.NCEP.NOAA.GOV/5KM_GRIDS/5KM_GRIDSBODY.HTML  
HTTPS://WWW.WPC.NCEP.NOAA.GOV/QPF/DAY4-7.SHTML  
HTTPS://WWW.WPC.NCEP.NOAA.GOV/WWD/PWPF_D47/PWPF_MEDR.PHP?DAY=4  
HTTPS://WWW.WPC.NCEP.NOAA.GOV/HEAT_INDEX.SHTML  
 

 
 

 
 
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