141  
FXUS02 KWBC 080612  
PMDEPD  
 
EXTENDED FORECAST DISCUSSION  
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD  
111 AM EST FRI MAR 08 2019  
 
VALID 12Z MON MAR 11 2019 - 12Z FRI MAR 15 2019  
 
...ACTIVE WEATHER PATTERN FOR THE CENTRAL STATES THROUGH NEXT WEEK  
WITH ADDITIONAL SNOW POSSIBLE FOR THE HIGH PLAINS/UPPER MIDWEST...  
 
...HEAVY RAIN QUITE POSSIBLE OVER THE SOUTHEAST/TN VALLEY LATE  
NEXT WEEK...  
 
   
..OVERVIEW
 
 
THE WORK WEEK NEXT WEEK WILL FEATURE YET ANOTHER ROBUST LATE  
WINTER STORM LIFTING OUT OF THE SOUTHWEST TUESDAY TOWARD THE UPPER  
MIDWEST BY THURSDAY. THIS WILL LIKELY LEAD TO ANOTHER ROUND OF  
SNOW ACROSS THE HIGH PLAINS WITH RAIN/CONVECTION FOCUSED ACROSS  
THE SOUTHEAST AND TENNESSEE VALLEY. SLOW MOVEMENT OF THE COLD  
FRONT ALONG THE GULF COAST MAY INCREASE THE THREAT OF LOCALLY  
HEAVY RAIN WITH THE POTENTIAL FOR SEVERAL INCHES OF RAIN AND  
FLOODING CONCERNS GIVEN RATHER WET ANTECEDENT CONDITIONS.  
 
   
..GUIDANCE AND UNCERTAINTY ASSESSMENT
 
 
DEEP TROUGHING NEAR CALIFORNIA AT THE START OF THE PERIOD MONDAY  
WILL HEAD EASTWARD THEN NORTHEASTWARD ATOP BUILDING RIDGING INTO  
CUBA. ENSEMBLES HAVE BEEN SPLIT ON THE TIMING OF THIS EVOLUTION  
WITH THE GEFS MEMBERS QUICKER THAN THE ECMWF AND CANADIAN  
ENSEMBLES. MOST RECENT 12Z AND 18Z GEFS HAVE TRENDED SLOWER WITH  
THE PROGRESSION WHILE THE ECMWF/CANADIAN ENSEMBLES REMAINED  
STEADY. WITH THE 18Z FV3-GFS NEARER TO THE 12Z ECMWF THAN THE  
OPERATIONAL 18Z GFS, PLACED MUCH MORE EMPHASIS ON THE 12Z  
ECMWF-LED CLUSTER THAT INCLUDED THE UKMET AND CANADIAN WITH THE  
12Z ECMWF ENSEMBLE MEAN AND 12Z NAEFS MEAN. BY NEXT THU/FRI, THE  
SURFACE LOW WILL EXIT THROUGH THE GREAT LAKES AND SOUTHERN ONTARIO  
INTO QUEBEC BUT ITS ATTENDANT COLD FRONT WILL SLOW AS IT RUNS INTO  
THE RIDGING TO THE EAST AND BECOMES ORIENTED NEAR-PARALLEL TO THE  
UPPER FLOW. ADDITIONAL HEIGHT FALLS UPSTREAM THROUGH THE GREAT  
BASIN ON WEDNESDAY WILL ALSO ACT TO SLOW THE TROUGH PROGRESSION  
EASTWARD ALONG THE GULF COAST. ENSEMBLES WERE IN GOOD AGREEMENT IN  
THE EAST OVERALL BUT DIFFERED ON THE DETAILS INCLUDING POSSIBLE  
SURFACE WAVE DEVELOPMENT ALONG THE COLD FRONT.  
 
   
..WEATHER HIGHLIGHTS AND HAZARDS
 
 
SNOW WILL EXIT NEW ENGLAND MONDAY THOUGH LAKE-ENHANCED SNOW WILL  
PERSIST ON THE WINDY BACKSIDE FLOW AROUND THE EXITING DEEP LOW  
UNTIL A SURFACE HIGH BUILDS IN BY TUESDAY. AREAS OF RAIN AND  
THUNDERSTORM ACTIVITY WILL PERSIST ACROSS THE GULF COAST REGION  
ALONG/AHEAD OF A FRONTAL BOUNDARY. COLDER THAN AVERAGE  
TEMPERATURES WILL PERSIST OVER MUCH OF THE WESTERN STATES ON THE  
ORDER OF 5-15F BELOW CLIMO. TEMPERATURES IN THE EAST WILL BE A BIT  
MORE VARIABLE--NEAR AVERAGE EARLY IN THE WEEK BUT TRENDING MILDER  
LATER IN THE WEEK AHEAD OF THE CENTRAL PLAINS SYSTEM.  
 
MAIN SYSTEM OF INTEREST IN THE MEDIUM RANGE WILL START IN THE  
WEST/SOUTHWEST WITH PRECIPITATION MOVING THROUGH SOUTHERN  
CALIFORNIA AND THE SOUTHWEST DESERTS. PRECIPITATION WILL EXPAND IN  
COVERAGE FROM NEW MEXICO EASTWARD, FOCUSED ON THE CENTRAL/SOUTHERN  
PLAINS FROM KS SOUTHWARD TO NORTHERN TEXAS TUE/WED AS THE SURFACE  
LOW DEEPENS FROM NEW MEXICO INTO SOUTHWESTERN KANSAS. FRONT ACROSS  
THE GULF WILL LIFT NORTHWARD AS THE LOW HEADS TOWARD MINNESOTA BY  
THURSDAY MORNING WHICH WILL BRING WIDESPREAD RAINFALL AND EMBEDDED  
CONVECTION INTO THE MISSISSIPPI/TENNESSEE VALLEY. THE POTENTIAL  
FOR SEVERAL INCHES OF RAIN EXISTS OVER A LARGE AREA THAT WILL BE  
FURTHER REFINED OVER THE NEXT SEVERAL DAYS. ATMOSPHERIC AND  
ENSEMBLE SIGNALS WERE NOTABLE EVEN AT THIS LEAD TIME BUT QPF WAS  
KEPT LOWER THAN ANY GIVEN MODEL GIVEN TIMING/DETAIL UNCERTAINTY.  
TO THE NORTH, COLD ENOUGH AIR WILL SUPPORT SNOW ON THE  
NORTHWEST/NORTH SIDE OF THE SURFACE LOW THAT WILL OCCUR WITH  
STRONG WINDS (I.E., POSSIBLE BLIZZARD CONDITIONS).  
 
FRACASSO  
 
ADDITIONAL 3-7 DAY HAZARDS INFORMATION CAN BE FOUND ON THE WPC  
MEDIUM RANGE HAZARDS CHART AT:  
HTTPS://WWW.WPC.NCEP.NOAA.GOV/THREATS/THREATS.PHP  
 
WPC MEDIUM RANGE 500MB HEIGHTS, SURFACE SYSTEMS, WEATHER GRIDS,  
QUANTITATIVE PRECIPITATION, WINTER WEATHER OUTLOOK PROBABILITIES  
AND HEAT INDICES ARE AT:  
 
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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