292  
FXUS61 KPBZ 201806  
AFDPBZ  
 
AREA FORECAST DISCUSSION  
NATIONAL WEATHER SERVICE PITTSBURGH PA  
106 PM EST SUN JAN 20 2019  
   
SYNOPSIS
 
 
OLD MAN WINTER IS HERE! BITTERLY COLD TEMPERATURES TONIGHT AND  
MONDAY NIGHT. WIND CHILLS WILL BE THE LOWEST TONIGHT. THE ACTIVE  
WEATHER PATTERN ROLLS ON WITH THE NEXT SYSTEM MIDWEEK. THERE COULD  
BE A WINTRY MIX WEDNESDAY MORNING FOR PARTS OF THE AREA. A BRIEF  
WARM UP TO ABOVE NORMAL TEMPERATURES WEDNESDAY, BEFORE A RETURN OF  
ARCTIC AIR FOR LATE WEEK.  
 

 
   
NEAR TERM /THROUGH MONDAY/
 
 
WILL LET HEADLINES EXPIRE FOR THE MOUNTAINS AS THE WORSE OF THE  
WEATHER IS OVER. LAKE ENHANCED BANDS WILL CONTINUE TO GENERATE  
SCATTERED SNOW SHOWERS THE REST OF THE DAY GIVEN DELTA TS. NAM3KM  
DOES A GOOD JOB ILLUSTRATING IT AS IT PIVOTS THROUGH UNTIL 6Z. WOULD  
NOT BE SURPRISED TO SEE 1-2" OF FLUFFY SNOW BE REPORTED WITH THIS  
BAND AS DGZ IS AT THE GROUND OFFSETTING HIGHER SNOWFALL.  
 
FLURRIES WON'T LEAVE THE MOUNTAINS UNTIL RIDGING IS RIGHT ON TOP OF  
US, SO WILL CARRY FLURRY MENTION FOR MOST OF THE DAY MONDAY, BUT NO  
ACCUMULATION. COLD WILL BE THE MAIN WEATHER HEADLINE MLK DAY WITH  
H8 TEMPS AROUND -20C. DESPITE WEAK WARM ADVECTION AT THIS LEVEL, DO  
NOT SEE TEMPS MAKING IT OUT OF THE MIDDLE TEENS EVEN FOR SOUTHERN  
AREAS, WHILE UP NORTH UPPER SINGLE DIGITS ARE LIKELY. WIND CHILL  
VALUES WILL BOTTOM OUT IN THE -10 TO -25 RANGE AND SLOWLY WORK THEIR  
WAY UP TO THE NEGATIVE SINGLE DIGITS MONDAY AFTERNOON.  
 
WIND CHILL HEADLINES REMAIN UNCHANGED.  
 

 
   
SHORT TERM /MONDAY NIGHT THROUGH WEDNESDAY NIGHT/
 
 
WE START OUT WITH THE COLDEST NIGHT OF THE SEASON TEMPERATURE WISE.  
ALL THINGS COMING TOGETHER FOR A WIDE SPREAD OF SUB ZERO TEMPS TO  
MIDDLE SINGLE DIGIT VALUES; CLEAR NIGHT, CALM WIND, AND SNOW PACK.  
SOME OF THE DEEPER HOLLOWS / VALLEYS MAY PUSH -10F BY DAYBREAK  
TUESDAY. WIND CHILL VALUES WILL BE RIGHT AROUND THE AMBIENT AIR  
TEMPERATURE GIVEN FORECAST WIND SPEED.  
 
ARCTIC AIR AS USUAL IS VERY SHALLOW AND STRONG WARM ADVECTION ON THE  
BACKSIDE OF THE ANTICYCLONE WILL GIVE BIG BOOSTS TO OUR TEMPERATURES  
TUESDAY AND WEDNESDAY. BY WEDNESDAY, AFTERNOON HIGHS WILL BE NEARLY  
40 DEGREES WARMER THAN AT DAWN MLK DAY. THE ONLY CONUNDRUM WITH  
THIS IS WE HAVE OUR NEXT WEATHER SYSTEM FAST APPROACHING FROM THE  
SOUTH. PTYPE WILL BE A CONCERN AT THE ONSET, ESPECIALLY ACROSS  
NORTHWEST PA AND THE MOUNTAINS WHERE SEVERAL DAYS OF SUB 32F WEATHER  
WILL MAKE THE GROUND COLD, SO FREEZING RAIN COULD BE OBSERVED AT THE  
ONSET DESPITE HAVING SURFACE TEMPERATURES ABOVE FREEZING. THE  
STRENGTH OF THE WARM LAYER ALOFT STILL BRINGS INTO QUESTION MORE  
THAN ONE PTYPE. WOULD NOT BE SURPRISED IF IT STARTS OUT AS SNOW  
THEN A WINTRY MIX TO RAIN BY AFTERNOON. WINTER WEATHER ADVISORIES  
MAY BE NEEDED FOR THIS PERIOD. ALL AREAS WILL SWITCH TO RAIN AS  
SOUTHERLY WINDS BRING THE ENTIRE COLUMN ABOVE FREEZING AS WE MOVE  
INTO THE WARM SECTOR DURING THE AFTERNOON. THE ASSOCIATED COLD  
FRONT MOVES DURING THE NIGHT AND WILL SPREAD WIDESPREAD RAIN TO THE  
REGION. BOUNDARY LAYER TEMPERATURES COLLAPSE WITH THE NEXT SHOT OF  
COLD AIR BEHIND IT, SO SNOW IS LIKELY BEFORE EVERYTHING WINDS DOWN.  
ACCUMULATIONS AT THIS JUNCTURE WILL BE LIGHT.  
 

 
   
LONG TERM /THURSDAY THROUGH SUNDAY/
 
 
HIGHLIGHTS:  
- STRONG FRONT FRIDAY  
- WEEKEND ARCTIC BLAST  
- BELOW NORMAL TEMPERATURES  
 
POST FRONTAL SNOW SHOWERS THURSDAY WON'T BE THAT BAD GIVEN FLOW IS  
WESTERLY AND TRAJECTORY OF LOW PRESSURE SYSTEM. THERE IS A BETTER  
CHANCE THURSDAY NIGHT AS THE ASSOCIATED UPPER AIR SHORTWAVE TROUGH  
PASSES.  
 
LONG RANGE MODELS CONTINUE TO STRESS A POTENT FRONT CROSSING FRIDAY.  
IT COULD BE ONE THAT GENERATES SNOW SQUALL WARNINGS PER AMOUNT OF  
LOW LEVEL INSTABILITY AND TEMPERATURE GRADIENT ASSOCIATED WITH IT.  
STILL TO EARLY NOW FOR THE HWO MENTION, BUT DEFINITELY SOMETHING TO  
KEEP AN EYE AS THE WEEK GOES BY. IN WAKE OF THE BAROCLINIC ZONE,  
BELOW NORMAL TEMPERATURES AS H8 TEMPS BOTTOM OUT AGAIN IN THE -20C  
RANGE. THIS WOULD EQUATE TO HIGHS / LOWS SOMEWHAT SIMILAR TO WHAT  
WE WILL SEE ON MLK DAY, PERHAPS A LITTLE WARMER. WIND CHILLS COULD  
BE A CONCERN ON FRIDAY AS WELL.  
 
THE UPCOMING WEEKEND LOOKS COLD AND CLOUDY WITH SCATTERED SNOW  
SHOWERS, BUT NO SIGNIFICANT ACCUMULATION.  
 

 
   
AVIATION /18Z SUNDAY THROUGH FRIDAY/
 
 
NORTHWEST FLOW OFF OF LAKE ERIE WILL KEEP MVFR CEILINGS INTO  
THIS EVENING ACROSS MANY TERMINALS, THERE ARE ENOUGH BREAKS IN  
THE CLOUDS TO SUPPORT VFR CONDITIONS AT TIMES. BANDED SNOW  
SHOWERS WILL SUPPORT SHORT-TERM VISIBILITY RESTRICTIONS TO IFR  
AT LEAST BRIEFLY, AND WIND GUSTING TO BETWEEN 20 AND 30 KNOTS  
WILL ALSO CONTINUE TO CREATE BLOWING SNOW CONCERNS, ESPECIALLY  
NORTH OF PIT.  
 
WINDS WILL CONTINUE TO GUST TONIGHT, WITH CONTINUED OCCASIONAL  
MVFR CIG/VIS IN ISOLATED/SCATTERED SNOW SHOWERS. THESE WILL  
BREAK UP MONDAY MORNING, WITH VFR CONDITIONS POTENTIALLY  
AREAWIDE BY THE AFTERNOON.  
 
CEILINGS WILL REMAIN MOSTLY IFR WITH INTERMITTENT MVFR ACROSS  
ALL SITES OVERNIGHT SAVE FOR DUJ AND FKL WHERE HEAVIER SNOW IS  
EXPECTED TO DROP VISIBILITIES TO LIFR. SNOW WILL EXIT THE AREA  
SUNDAY MORNING FROM WEST TO EAST AFTER SUNRISE, WITH A RETURN TO  
MVFR/VFR AT MOST SITES DURING THE AFTERNOON. WIND WILL ALSO  
BEGIN TO RELAX TOMORROW AS THE PRESSURE GRADIENT DECREASES.  
   
OUTLOOK
 
 
RESTRICTIONS ARE LIKELY AGAIN WITH A TUE NIGHT/WED COLD FRONT.  
 

 
   
PBZ WATCHES/WARNINGS/ADVISORIES
 
 
MD...WIND CHILL WARNING FROM 7 PM THIS EVENING TO 1 PM EST MONDAY  
FOR MDZ001.  
OH...WIND CHILL ADVISORY FROM 7 PM THIS EVENING TO 1 PM EST MONDAY  
FOR OHZ039>041-048>050-057>059-068-069.  
PA...WIND CHILL ADVISORY FROM 7 PM THIS EVENING TO 1 PM EST MONDAY  
FOR PAZ007>009-013>016-020>023-029-031-073-075.  
WIND CHILL WARNING FROM 7 PM THIS EVENING TO 1 PM EST MONDAY  
FOR PAZ074-076.  
WV...WIND CHILL ADVISORY FROM 7 PM THIS EVENING TO 1 PM EST MONDAY  
FOR WVZ001>004-012-021-509-510.  
WIND CHILL WARNING FROM 7 PM THIS EVENING TO 1 PM EST MONDAY  
FOR WVZ511>514.  
 

 
 

 
 
98/CL  
 
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