774  
FXUS02 KWBC 021618  
PMDEPD  
 
EXTENDED FORECAST DISCUSSION  
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD  
1117 AM EST SAT FEB 02 2019  
 
VALID 12Z TUE FEB 05 2019 - 12Z SAT FEB 09 2019  
 
...GUIDANCE/PREDICTABILITY ASSESSMENT AND WEATHER  
HIGHLIGHTS/HAZARDS...  
 
MODELS AND ENSEMBLES AGREE IN SHOWING ANOTHER STORMY PATTERN  
ACROSS THE LOWER 48 STATES NEXT WEEK. THIS WILL BE HIGHLIGHTED  
TUESDAY BY A DEEPENED LOW PRESSURE CENTER EXITING THE NORTHEAST  
AND ANOTHER POTENT/WET STORM WORKING INTO CALIFORNIA AND AN  
UNSETTLED/WINTERY WEST. ARCTIC AIR WILL SPILL DOWN OVER THE  
NORTH-CENTRAL THROUGH NORTHEASTERN U.S. IN THE WAKE OF THE  
NORTHEAST STORM. AN UNCERTAIN SERIES OF SMALLER SCALE IMPULSES  
WILL ACT TO INDUCE LOCAL PRECIPITATION FOCUSING FRONTAL WAVES ON  
THE LEADING EDGE OF THE ARCTIC CHILL.  
 
GUIDANCE CONTINUES TO BE QUITE DATA SENSITIVE AND VARIED WITH  
RESPECT TO SUBSEQUENT PROGRESSION AND PHASING POTENTIAL OF THE  
MAIN CALIFORNIA SYSTEM WED-FRI ON A GENERAL TRACK NORTHEASTWARD  
ACROSS THE CENTRAL AND NORTHEASTERN U.S. DESPITE TIMING ISSUES,  
THIS STORM OFFERS A CONSIDERABLE THREAT OF HEAVY SNOW/ICE IN THE  
ARCTIC AIR IN PLACE TO THE NORTH OF E MAIN LOW TRACK OVER THE  
N-CENTRAL THROUGH NORTHEASTERN STATES ALONG WITH SOME THREAT OF  
HEAVY WARM SECTOR RAINS/CONVECTION. THE DEEPENED ARCTIC AIRMASS IS  
SLATED TO SPREAD ARCOSS MUCH OF THE NATION IN THE WAKE OF THIS  
SYSTEM. GIVEN UNCERTAINTY, THE WPC MEDIUM RANGE PRODUCT SUITE WAS  
PRIMARILY DERIVED FROM A COMPOSITE GUIDANCE SOLUTION THAT INCLUDES  
THE LATEST GFS/ECMWF/CANADIAN AND GEFS/ECMWF ENSEMBLES. ENSEMBLE  
MEMBERSHIP IS SO VARIED IN TIMINGS THAT INCLUSION OF ALSO VARIED  
DETERMINISTIC MODEL GUIDANCE WAS NEEDED TO SHOW AMPLE SYSTEM  
DEVELOPMENTS CONSISTENT WITH DYNAMIC SUPPORT ALOFT. THIS TYPE OF  
BLENDED SOLUTION IS NOT IDEAL, BUT THE RESULTANT SYSTEM DEPICTIONS  
PRODUCED IN THIS MANNER SEEMS TO OFFER A FAIR FLOW REPRESENTATION.  
 
IN THIS PATTERN, TEMPERATURES WILL BE MUCH BELOW AVERAGE (20-40  
DEGREES NEGATIVE ANOMALIES) OVER THE NORTHERN PLAINS/VICINITY NEXT  
WEEK BEHIND THE ARCTIC FRONT. THE EAST/SOUTHEAST WILL SEE MUCH  
MILDER TEMPERATURES AHEAD OF A LEAD COLD FRONT TUE/WED THAT AGAIN  
RISE THU/FRI AHEAD OF THE NEXT ARCTIC SURGE BEFORE THAT FRONT  
PUSHES OFFSHORE. SOME RECORD HIGHS ARE POSSIBLE.  
 
SCHICHTEL  
 
WPC MEDIUM RANGE 500MB HEIGHTS, SURFACE SYSTEMS, WEATHER GRIDS,  
QUANTITATIVE PRECIPITATION AND WINTER WEATHER OUTLOOK  
PROBABILITIES ARE FOUND 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  
 

 
 
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