203  
FXUS61 KRNK 190806  
AFDRNK  
 
AREA FORECAST DISCUSSION  
NATIONAL WEATHER SERVICE BLACKSBURG VA  
406 AM EDT THU OCT 19 2017  
   
SYNOPSIS
 
 
A LARGE AREA OF HIGH PRESSURE WILL REMAIN OVER THE EASTERN PART  
OF THE COUNTRY THIS WEEK BEFORE SLOWLY SLIDING OFF THE COAST ON  
SATURDAY. THIS WILL KEEP SKIES MOSTLY SUNNY AND ALLOW  
TEMPERATURES TO WARM TO ABOVE NORMAL LEVELS. EARLY NEXT WEEK, A  
STRONG COLD FRONT AND DEEP UPPER TROUGH WILL APPROACH FROM THE  
MIDWEST BRINGING WIDESPREAD RAIN SHOWERS FOLLOWED BY MUCH COOLER  
TEMPERATURES.  
 

 
   
NEAR TERM /THROUGH TONIGHT/
 
 
AS OF 350 AM EDT THURSDAY...  
 
SURFACE HIGH PRESSURE WILL REMAIN FIRMLY ENTRENCHED ACROSS THE  
AREA TODAY ALLOWING FOR ANOTHER BRIGHT, BLUE, SUNNY DAY. A WEAK  
AND DRY UPPER-LEVEL TROUGH WAS PASSING OVER THE AREA THIS  
MORNING WITH THE ONLY NOTABLE ASSOCIATED WEATHER SOME PASSING  
HIGH CLOUDS. THIS WEAK UPPER TROUGH WILL CONTINUE TO MOVE EAST  
OF THE AREA TODAY AS RIDGING ALOFT DEVELOPS JUST UPSTREAM OF THE  
AREA. 850MB TEMPERATURES WILL CONTINUE TO HOVER IN THE +10C TO  
+12C RANGE TODAY, YIELDING TEMPERATURES ON PAR WITH WHAT WE SAW  
WEDNESDAY. HOWEVER, WITH THE CENTER OF THE LARGE SURFACE HIGH  
SHIFTING TOWARD THE EASTERN PART OF THE CWA, WINDS WILL COME  
AROUND TO THE SOUTHWEST BY AFTERNOON FOR AREAS WEST OF THE BLUE  
RIDGE. THIS SHOULD ALLOW TEMPERATURES TO CREEP UP A FEW DEGREES  
IN COMPARISON TO WHAT WE SAW YESTERDAY. WITH THE CENTER OF THE  
COOL HIGH ACROSS EASTERN AREAS, THEY SHOULD BE THE COOLEST  
OVERALL TODAY. MAXIMUM TEMPERATURES WILL BE 5-10 DEGREES ABOVE  
NORMAL AND MOSTLY IN THE 70S, EXCEPT 60S HIGHER ELEVATIONS.  
 
MINIMUM TEMPERATURES FRIDAY MORNING WILL CONTINUE TO WARM A FEW  
DEGREES COMPARED TO THE PREVIOUS DAY AND ALL LOCATIONS SHOULD  
REMAIN AT OR ABOVE 37F, MAINLY IN THE 40S ACROSS THE FORECAST  
AREA. THUS, NO FROST WAS INCLUDED IN THE GRIDS AT THIS TIME.  
PATCHY FOG MAY DEVELOP IN RIVER AND MOUNTAIN VALLEYS MAINLY WEST  
OF THE BLUE RIDGE.  
 

 
   
SHORT TERM /FRIDAY THROUGH SUNDAY NIGHT/
 
 
AS OF 300 AM EDT THURSDAY...  
 
AN AWESOME WEEKEND IS SHAPING UP WEATHERWISE AS A STRONG RIDGE OF  
HIGH PRESSURE IS FORECAST TO LINGER THROUGH SUNDAY. THIS FEATURE  
WILL MAINTAIN THE FAIR DRY WEATHER, WITH TEMPERATURES 5 TO 10  
DEGREES ABOVE NORMAL.  
 
ENJOY THE WEEKEND BECAUSE NEXT WEEK WILL BE UNSETTLED. CLOUDS WILL  
BEGIN TO INCREASE LATE SUNDAY, AN INDICATION OF CHANGES ON THE  
HORIZON.  
 

 
   
LONG TERM /MONDAY THROUGH WEDNESDAY/
 
 
AS OF 300 AM EDT THURSDAY...  
 
AN ACTIVE UPPER AIR PATTERN IS FORECAST FOR NEXT WEEK AS FULL  
LATITUDE LONG WAVE TROUGH GETS CARVED OUT OVER THE EAST CENTRAL  
CONTINENTAL U.S. (CONUS). MODELS INDICATE AN ABUNDANCE OF SHORT  
WAVE ENERGY FLOWING INTO THE WESTERN CONUS THIS WEEKEND WITH SOME OF  
THE ENERGY BECOMING ISOLATED ON THE WEST SIDE OF SUBTROPICAL RIDGE  
OF HIGH PRESSURE OVER THE SOUTHEAST U.S., AND DEVELOPING INTO A  
CUTOFF LOW IN THE VICINITY OF THE LOWER MS VALLEY. THIS CUTOFF LOW  
IS FORECAST TO EJECT NORTHEAST ACROSS THE MID-ATLANTIC MONDAY INTO  
TUESDAY IN AN ALMOST WINTERLIKE FASHION AS THIS ENERGY PHASES WITH  
AN EVER INCREASING ENERGETIC NORTHERN STREAM TROUGH ALONG THE U.S.  
CANADIAN BORDER. THE NET RESULT WILL BE A HIGHLY AMPLIFIED FULL  
LATITUDE LONG WAVE TROUGH BY MID-WEEK WHICH WILL FEATURE A  
SIGNIFICANT CHANGE IN TEMPERATURE FOR MUCH OF THE EASTERN U.S.  
 
MODEL CONSENSUS IS FOR RAIN TO DEVELOP FROM SOUTHWEST TO NORTHEAST  
ACROSS THE REGION SUNDAY NIGHT INTO MONDAY, WITH THE HIGHEST  
PROBABILITY FOR MEASURABLE RAINFALL OCCURRING MONDAY NIGHT INTO  
TUESDAY AS THE SOUTHERN STREAM LOW EJECTS NORTHEAST ACROSS THE  
REGION. STABILITY INDICES SUGGEST SLIGHT POTENTIAL FOR THUNDER TUE.  
 
WITH THE UPPER TROUGH BECOMING ESTABLISHED OVER THE EASTERN CONUS  
FOR MID WEEK, TEMPERATURES WILL TAKE A TUMBLE. ARRIVAL OF COOLER AIR  
TUESDAY NIGHT INTO WEDNESDAY MAY RESULT IN SOME P-TYPE TRANSITION  
(WET SNOWFLAKES?) FOR THE HIGHEST ELEVATIONS OF WV/NC AND FAR  
WESTERN VA, FOLLOWED BY BRISK/BREEZY CONDITIONS.  
 

 
   
AVIATION /08Z THURSDAY THROUGH MONDAY/
 
 
AS OF 200 AM EDT THURSDAY...  
 
HIGH PRESSURE WILL REMAIN ACROSS THE REGION AT THE SURFACE  
THROUGH THE PERIOD. A WEAK UPPER TROUGH WILL PASS OVER THE AREA  
TONIGHT ASSOCIATED WITH PATCHY CIRRUS THROUGH THE EARLY MORNING  
AND A WIND SHIFT MORE TO THE WEST AFTER SUNRISE. OTHER THAN  
PATCHY MVFR TO POTENTIALLY IFR/LIFR BR/FG AT LWB AND BCB,  
CONDITIONS ARE EXPECTED TO REMAIN VFR AND LARGELY SKC THROUGH  
THE TAF VALID PERIOD.  
 
WINDS CALM MOST LOCATIONS THROUGH DAYBREAK BECOMING GENERALLY  
SW-WSW 4-6KTS AFTER 14Z.  
 
HIGH CONFIDENCE IN CEILINGS THROUGH THE TAF VALID PERIOD.  
HIGH CONFIDENCE IN VISIBILITIES THROUGH THE TAF VALID PERIOD,  
EXCEPT MEDIUM CONFIDENCE LWB/BCB 10Z-13Z THIS MORNING.  
MEDIUM CONFIDENCE IN WIND DIRECTION, HIGH CONFIDENCE IN WIND  
SPEED THROUGH THE TAF VALID PERIOD.  
 
EXTENDED AVIATION DISCUSSION...  
 
HIGH PRESSURE WILL REMAIN OVER THE REGION THROUGH SUNDAY WITH  
GENERALLY VFR CONDITIONS EXPECTED, OUTSIDE THE USUAL LATE  
NIGHT/EARLY MORNING PATCHY RIVER AND MOUNTAIN VALLEY FOG.  
A DEEP UPPER TROUGH AND ASSOCIATED STRONG COLD FRONT WILL MOVE  
INTO THE REGION FROM THE WEST BY MONDAY PROMISING A PERIOD OF  
SUB-VFR CONDITIONS IN RAIN/SHOWERS ALONG WITH INCREASING WIND.  
COLDER, BLUSTERY, UNSETTLED WEATHER WITH PERHAPS LARGELY MVFR  
CONDITIONS ACROSS THE MOUNTAINS WILL LINGER THROUGH THE LATER  
HALF OF NEXT WEEK AS AN UPPER TROUGH CUTS OFF ACROSS THE CENTRAL  
APPALACHIANS.  
 

 
   
RNK WATCHES/WARNINGS/ADVISORIES
 
 
VA...NONE.  
NC...NONE.  
WV...NONE.  
 

 
 

 
SYNOPSIS...RAB  
NEAR TERM...RAB  
SHORT TERM...PM  
LONG TERM...PM/WP  
AVIATION...JH/RAB  
 
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