969  
FXUS02 KWBC 090641  
PMDEPD  
 
EXTENDED FORECAST DISCUSSION  
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD  
141 AM EST SAT MAR 09 2019  
 
VALID 12Z TUE MAR 12 2019 - 12Z SAT MAR 16 2019  
   
..NORTH-CENTRAL U.S. HEAVY SNOW THREAT WED-THU
 
 
...SOUTH-CENTRAL TO MID-SOUTH/SOUTHEAST U.S. HEAVY RAIN THREAT  
TUE-FRI...  
 
   
..OVERVIEW
 
 
ANOTHER POTENT STORM SYSTEM WILL TREK OUT OF THE SOUTHWEST/FOUR  
CORNERS REGION TUESDAY AND LIFT NORTHEASTWARD TOWARD THE GREAT  
LAKES BY THURSDAY. THIS WILL SPREAD A LARGE AREA OF POTENTIALLY  
HEAVY RAIN FROM THE SOUTHERN PLAINS EASTWARD INTO THE SOUTHEAST  
WHILE MARGINALLY COLD AIR TO THE NORTH WILL SUPPORT A HEAVY  
SNOWFALL THREAT OVER THE HIGH PLAINS AND UPPER MIDWEST. BY THE  
START OF NEXT WEEKEND, THE PATTERN APPEARS TO BE MUCH QUIETER WITH  
HIGH PRESSURE FORECAST TO DOMINATE THE WESTERN/CENTRAL PARTS OF  
THE LOWER 48.  
 
   
..GUIDANCE AND UNCERTAINTY ASSESSMENT
 
 
THE ECMWF HAS LED THE WAY WITH THE TIMING OF THE SYSTEM OUT OF THE  
SOUTHWEST, BUT THE GFS (ESPECIALLY THE 18Z FV3-GFS) CLUSTERED WELL  
WITH THE 18Z GEFS MEAN AND THE 12Z ECMWF/ECMWF ENSEMBLE MEAN SO  
THAT A BLEND/CONSENSUS POSITION OFFERED A REASONABLE STARTING  
POINT. BY NEXT FRI/SAT, THE UPSTREAM PACIFIC WILL BECOME MORE  
UNCERTAIN AS THE SHAPE OF THE UPPER RIDGE INTO BRITISH COLUMBIA  
WILL DICTATE THE AMOUNT/STRENGTH/ORIENTATION OF TROUGHING IN THE  
WEST/ROCKIES.  
 
   
..WEATHER HIGHLIGHTS AND HAZARDS
 
 
MAIN SYSTEM OF INTEREST IN THE MEDIUM RANGE WILL LIFT OUT OF THE  
SOUTHWEST AND DEEPEN QUITE SMARTLY INTO SOUTHEASTERN COLORADO BY  
WEDNESDAY MORNING. PRECIPITATION WILL EXPAND IN COVERAGE OUT OF  
ARIZONA AND NEW MEXICO EASTWARD, FOCUSED ON THE CENTRAL/SOUTHERN  
PLAINS (NORTHERN TEXAS NORTHWARD) TUE/WED. TO THE EAST, A FRONT  
ACROSS THE GULF WILL LIFT NORTHWARD AS A WARM FRONT AND BRING  
WIDESPREAD RAINFALL AND EMBEDDED CONVECTION INTO THE  
MISSISSIPPI/TENNESSEE VALLEY WEDNESDAY THEN INTO  
ALABAMA/GEORGIA/SOUTHERN APPALACHIANS THURSDAY. THE POTENTIAL FOR  
SEVERAL INCHES OF RAIN EXISTS OVER A LARGE AREA THAT WILL BE  
FURTHER REFINED OVER THE NEXT SEVERAL DAYS, BUT ATMOSPHERIC AND  
ENSEMBLE SIGNALS CONTINUE TO BE STRONG. 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). A COLD RAIN (PERHAPS OVER AN INCH TO AN INCH AND A  
HALF) WILL FALL TO THE SOUTHEAST OF THE SURFACE LOW OVER SOME  
AREAS THAT WILL RECEIVE SIGNIFICANT SNOW IN THE SHORT TERM (E.G.,  
SOUTHERN MINNESOTA). THE SURFACE LOW WILL DEPART THROUGH SOUTHERN  
CANADA FRIDAY AS COLDER AIR IS DRAGGED IN BEHIND IT ACROSS THE  
GREAT LAKES, ENHANCING LAKE-EFFECT SNOWS.  
 
TEMPERATURES WILL REMAIN BELOW AVERAGE IN THE WEST BUT PERHAPS  
MODERATE JUST A BIT BY NEXT WEEKEND. IN THE EAST, POST-FRONT  
AIRMASS TUESDAY WILL BE CHILLY (BELOW AVERAGE BY A FEW DEGREES)  
BUT THEN WARM UP AHEAD OF THE CENTRAL STATES' SYSTEM BY THURSDAY  
INTO FRIDAY.  
 
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  
 

 
 
CLICK HERE TO GO TO PREVIOUS BULLETINS.

The Nexlab HPC Page Main Text Page