826  
FXUS02 KWBC 150541  
PMDEPD  
 
EXTENDED FORECAST DISCUSSION  
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD  
140 AM EDT MON OCT 15 2018  
 
VALID 12Z THU OCT 18 2018 - 12Z MON OCT 22 2018  
   
..PATTERN OVERVIEW AND GUIDANCE/PREDICTABILITY ASSESSMENT
 
 
MODELS/ENSEMBLES CONTINUE TO SHOW GOOD AGREEMENT ON THE LONGWAVE  
PATTERN OVER THE LOWER 48 THROUGH THE WEEKEND INTO NEXT WEEK. WITH  
UPPER RIDGING OVER BRITISH COLUMBIA AND FLORIDA, TROUGHING WILL BE  
FAVORED THROUGH THE NORTHERN TIER EAST OF THE ROCKIES WITH A  
CLOSED LOW LINGERING ACROSS THE SOUTHWEST. THIS WILL TAKE A COUPLE  
COLD FRONTS OUT OF WESTERN CANADA AND THROUGH THE GREAT  
LAKES/NORTHEAST INTO THE SOUTHEAST. A MULTI-MODEL DETERMINISTIC  
BLEND SUFFICED FOR THE FORECAST THU-SAT. BY SUNDAY, THE LEAD FRONT  
WILL BE OFFSHORE THE NORTHEAST/MID-ATLANTIC WITH HIGH PRESSURE  
OVER THE PLAINS AND THE NEXT FRONT DIPPING SOUTHEASTWARD. MODELS  
DIVERGE ON TIMING OF THIS FRONT AND STRENGTH ACROSS CANADA BUT A  
TREND TOWARD THE ENSEMBLES SHOULD MINIMIZE ERROR. IN THE  
SOUTHWEST, THE CLOSED LOW WILL LIKELY MEANDER WESTWARD PER THE  
CONSENSUS WITH RIDGING MOVING EASTWARD INTO WA/OR/ID.  
 
   
..WEATHER HIGHLIGHTS/THREATS
 
 
BELOW AVERAGE TEMPERATURES WILL CONTINUE LATE THIS WEEK INTO NEXT  
MONDAY FOR THE SOUTHWEST THROUGH THE SOUTHERN PLAINS (ESPECIALLY  
TEXAS) NORTHEASTWARD THROUGH THE OHIO VALLEY INTO THE  
NORTHEAST/MID-ATLANTIC. ON THE WARM SIDE OF THE SOUTHERN  
STATIONARY FRONT, FLORIDA WILL SEE WARM/HOT TEMPERATURES THAT MAY  
TIE/BREAK RECORD HIGHS AT SOME LOCATIONS. UPPER RIDGING ACROSS THE  
PACIFIC NORTHWEST (WA/OR/ID INTO WESTERN MONTANA) WILL ALSO LEAD  
TO CONTINUED ABOVE AVERAGE TEMPERATURES FOR THAT REGION.  
 
THE SOUTHERN/CENTRAL TEXAS COAST WILL SEE THE MOST ORGANIZED  
RAINFALL THIS PERIOD ALONG AN INVERTED TROUGH AND JUST TO THE  
NORTHWEST OF A STATIONARY BOUNDARY IN THE WESTERN GULF. THE  
LINGERING UPPER LOW IN THE SOUTHWEST WILL SUPPORT RAIN/SNOW  
SHOWERS MOSTLY FOCUSED ON/ALONG THE HIGHER TERRAIN WHILE A  
STATIONARY FRONT ACROSS FLORIDA WILL KEEP DAILY SHOWER/STORM  
CHANCES IN THE FORECAST. THE REST OF THE LOWER 48 LOOKS TO BE  
LARGELY DRY WITH SOME GENERALLY LIGHT RAIN/SNOW SHOWERS AROUND THE  
LAKES AND INTO THE NORTHEAST ALONG/AHEAD OF THE COLD FRONT  
FRIDAY/SATURDAY.  
 
FRACASSO  
 
WPC MEDIUM RANGE 500 MB HEIGHTS, SURFACE SYSTEMS, WEATHER GRIDS,  
QUANTITATIVE PRECIPITATION, WINTER WEATHER OUTLOOK PROBABILITIES  
AND HEAT INDEXES 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  
HTTPS://WWW.WPC.NCEP.NOAA.GOV/HEAT_INDEX.SHTML  
 

 
 
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