HAMweather.com Area Forecast Discussion for County Warning Area PBZ

Thu, 16 Feb 2012 06:49:04 GMT
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PITTSBURGH PA
144 AM EST THU FEB 16 2012

.SYNOPSIS...
LOW PRESSURE WILL SPREAD RAIN SHOWERS ACROSS THE UPPER OHIO VALLEY
LATE TONIGHT AND THURSDAY.

.NEAR TERM /THROUGH THURSDAY NIGHT/... 
SPED UP TIMING OF PRECIP JUST A BIT AND RAISED POPS LATER TODAY
WITH NEW 00Z MODEL RUNS SHOWING CAT POPS REGION WIDE MID MORNING
INTO AFTERNOON. STILL SOME CONCERN WITH TEMPS IN THE FAR NORTHEAST
BUT TEMPERATURES ARE TENDING TO RISE WITH ONSET OF PRECIP WITH
LITTLE WET BULBING. KEPT A RAIN SNOW MIX IN THE NORTHEAST WITH A
CHANCE OF FREEZING RAIN JEFFERSON AND FOREST BEFORE DAYBREAK. STILL
APPEARS TO BE A MINIMAL EVENT IF IT OCCURS.

SHORTWAVE AND SURFACE LOW WILL TRANSITION EAST DURING THE DAY.
WARM ADVECTION WILL ALLOW TEMPERATURES TO RISE WELL ABOVE NORMAL
WITH ALL RAIN INTO EARLY EVENING. AS DEEP MOISTURE EXITS EAST BY
SUNSET COLD ADVECTION WILL PRODUCE SCATTERED RAIN SHOWERS
TRANSITIONING TO SNOW SHOWERS OVERNIGHT BEFORE ENDING. LITTLE IF
ANY ACCUMULATION EXPECTED. TEMPERATURES A CLOSE MODEL MOS BLEND.

.SHORT TERM /TONIGHT THROUGH 6 PM FRIDAY/...
SURFACE ANTICYCLONE YIELDS A HIGH CONFIDENCE FORECAST OF DRY
WEATHER FRI AND SAT. ZONAL FLOW ALOFT BRINGS SLIGHTLY ABOVE NORMAL
TEMPERATURES UNDER A MIXTURE OF CLOUDS AND SUNSHINE FRI AND SAT.

.LONG TERM /FRIDAY NIGHT THROUGH WEDNESDAY/...
HIGHLIGHTS...
- NO SIGNS OF ARCTIC AIR
- LOTS OF UNCERTAINTY IN THE SAT NGT - SUN TIME RANGE
- AT OR SLIGHTLY ABOVE NORMAL TEMPS NEXT WEEK

LOTS OF SPREAD IN THE ENSEMBLES AS ALLUDED TO IN BULLETS ABOVE RIGHT 
OUT OF THE GATE.  GEFS AND NAEFS MEANS KEEP SRN PLAINS SYSTEM FROM 
PHASING WITH THE NRN STREAM...THUS SHUNTING THE SFC LOW / QPF TO OUR 
S AND SE.  OPERATIONAL GFS PHASES THE TWO BRANCHES BRINGING LOW 
PRESSURE UP E OF THE MTNS...WHICH WOULD MEAN THE POTENTIAL FOR 
SIGNIFICANT SNOW IN THE RIDGES S AND E OF PIT SAT NGT AND SUN.  
HOWEVER...LEFT INHERITED FORECAST FOR CONSISTENCY AND LEVERAGE 
ENSEMBLE MEANS WITH CHANCE POPS.  PROB TOO LOW OF INCLUSION IN THE 
HAZARDOUS WEATHER OUTLOOK...BUT WE WILL CONTINUE TO MONITOR.  

MEDIUM CONFIDENCE WITH LESS MODEL SPREAD FOR EARLY NEXT WEEK.  HIGH 
PRESSURE WILL CONTROL OUR WEATHER AS MID LVL HEIGHTS BUILD MON AND 
TUE.  THE NEXT WEATHER SYSTEM SHOULD PASS TO OUR NW BRINGING ALL A
LIQUID PTYPE...BUT IF TIMING CHANGES AND PCPN ONSET IS DURING THE 
NIGHT OR EARLY MRNG HRS...CAN NOT RULE BRIEF PERIOD OF A WINTRY 
MIX.  TEMPERATURES WERE CONSTRUCTED USING THE BIAS CORRECTED 
MOS GUIDE.

.AVIATION /06Z THURSDAY THROUGH MONDAY/...
VFR CONDITIONS WILL DETERIORATE TO MVFR BY DAYBREAK AS THE LOW 
LEVELS MOISTEN AND RAIN BEGINS TO FALL. MAINTAINED LOW END MVFR CIGS 
THROUGHOUT THE DAY AT ALL SITES BUT KFKL AND KDUJ...THAT WERE 
BROUGHT TO IFR BY MIDDAY. 

HOWEVER...LOOKING AT THE UPSTREAM OBSERVATIONS AND THE MOST RECENT 
LAMP AND NAM/SREF GUIDANCE...IFR CIGS COULD VERY WELL BE POSSIBLE 
OUT AHEAD OF THE FRONTAL PASSAGE AT ALL SITES.  

OUTLOOK...THURSDAY NIGHT THROUGH MONDAY... 
CEILING RESTRICTIONS WILL CONTINUE THROUGH EARLY FRIDAY BEFORE
IMPROVEMENT TO VFR IN HIGH PRESSURE FOR THE BEGINNING OF THE
WEEKEND. ANOTHER SYSTEM PASSING TO THE SOUTHEAST MAY BRING
RESTRICTIONS SOUTHEAST OF KPIT WITH SNOW LATE SATURDAY AND SUNDAY. 
HIGH PRESSURE WILL RETURN VFR CONDITIONS FOR EARLY NEXT WEEK.

.PBZ WATCHES/WARNINGS/ADVISORIES...
MD...NONE.
OH...NONE.
PA...NONE.
WV...NONE.