FXUS61 KPBZ 220222 AAB
AFDPBZ
AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE PITTSBURGH PA
922 PM EST MON DEC 21 2009
.SYNOPSIS...
SCATTERED SNOW SHOWERS ARE POSSIBLE OVER THE NORTH AND RIDGES
TONIGHT. HIGH PRESSURE WILL BRING COLD AND DRY CONDITIONS
WEDNESDAY INTO THURSDAY.
&&
.NEAR TERM /THROUGH TUESDAY/...
NW FLOW ACROSS THE LAKES WILL KEEP IN THE RISK FOR SNOW SHOWERS
ACROSS THE NORTH AND RIDGES THROUGH 12Z. WIND SHEAR WILL KEEP ANY
DEVELOPMENT LIGHT AND SCATTERED. CURRENT MODEL RUNS KEEP NEXT WAVE
TO THE WEST OF THE REGION TUESDAY. TEMPERATURES TO REMAIN BELOW NORMAL.
&&
.SHORT TERM /TUESDAY NIGHT THROUGH THURSDAY/...
HIGH PRESSURE BUILDING INTO THE OHIO VALLEY WILL BRING DRY
WEATHER LATER FOR TUESDAY NIGHT INTO EARLY THURSDAY. LATER
THURSDAY AS A POWERFUL STORM DEVELOPS IN THE NATIONS MID SECTION
WITH MOISTURE STREAMING INTO THE REGION BY LATE DAY. FOR NOW IT
APPEARS ANY PRECIP THAT ARRIVES LATE DAY WILL START AS RAIN.
&&
.LONG TERM /THURSDAY NIGHT THROUGH MONDAY/...
A DEEP CLOSED LOW IS PROGGED TO BE ACROSS THE CENTRAL PLAINS
THURSDAY NIGHT WITH A BROAD AREA OF LIFT AHEAD OF THIS SYSTEM
BRINGING MIXED PRECIPITATION TO THE AREA BY THURSDAY NIGHT. GFS/NAM
CONTINUE TO TREND SLOWER AND WARMER WITH THE ARRIVAL OF THE
APPROACHING SYSTEM. GFS/ECMWF MODEL THICKNESSES ARE INDICATING THE
WARM WEDGE ALOFT CHANGING PRECIPITATION ACROSS THE LOWLANDS TO ALL
RAIN THURSDAY NIGHT. SNOWPACK AND ELEVATION WILL BE MORE CONDUCIVE
FOR SUBFREEZING GROUND TEMPS TO LINGER OVERNIGHT ACROSS THE EASTERN
RIDGES...WITH THE POTENTIAL FOR A FREEZING RAIN EVENT THERE THROUGH
CHRISTMAS MORNING. TEMPS WILL BE AROUND 5 DEGREES ABOVE NORMAL ON
CHRISTMAS...WITH WARM AIR ADVECTION AND LIKELY POPS CONTINUING
THROUGHOUT THE DAY.
ON CHRISTMAS NIGHT THE UPPER LEVEL LOW WILL LIFT NORTHEASTWARD INTO
THE UPPER GREAT LAKES AND A COLD FRONT WILL CROSS THE AREA. FORECAST
IS CLOSER TO A GFSE/HPC SOLUTION...ALTHOUGH THE 12Z ECMWF TRENDS
EVEN SLOWER WITH THE ARRIVAL OF THE FRONT. WITH THE PASSAGE OF THE
FRONT...PRECIPITATION WILL TURN OVER TO ALL SNOW BY SATURDAY MORNING
WITH COLD AIR ADVECTION THROUGH THE DAY. WITH THE TROUGH AXIS
CROSSING THE AREA THROUGH MONDAY...THE CHANCE OF SNOW SHOWERS ACROSS
THE AREA WILL CONTINUE. FORECAST HIGH TEMPERATURES WILL BE AROUND 5
DEGREES BELOW NORMAL THROUGH THE WEEKEND INTO MONDAY.
&&
.AVIATION /02Z TUESDAY THROUGH SATURDAY/...
A FEW LINGERING FLURRIES WITH PERIODS OF IFR CEILINGS WILL CONTINUE
ACROSS THE NORTHERN TERMINALS WITH MVFR CEILINGS PREVAILING
ELSEWHERE THIS EVENING. FOG/HAZE SEEMS TO BE GIVING WAY AND WE HAVE
SOME CONFIDENCE THIS WILL CONTINUE.
MID LEVEL FLOW OVER LAKE ERIE TURNS NORTHWEST LATER TONIGHT
SETTING UP LIGHT SNOW SHOWERS ACROSS NORTHERN AREAS. APPROACHING
WARM FRONT CAUSES MID DECK LATER TUE JUST AS LOWER CLOUDS DIMINISH.
NEXT, HIGH PRESSURE RIDGES DOWN FROM EASTERN CANADA TUE NIGHT, EATING
CLOUDS AND ALLOWING CONDITIONS TO RETURN TO VFR WED AND MOST OF
THU.
A LOW PRESSURE SYSTEM WILL DEVELOP ACROSS THE CENTRAL US AND BRING
THE POTENTIAL FOR A WINTRY MIX TO THE REGION WITH REDUCED
VISIBILITIES AND CEILINGS EXPECTED LATE THU INTO FRI. WITH THE
PASSAGE OF A COLD FRONT FRI NIGHT...PRECIPITATION WILL TURN TO
SNOW SHOWERS WITH REDUCED VISIBILITIES AND CEILINGS POSSIBLE SAT.
&&
.PBZ WATCHES/WARNINGS/ADVISORIES...
MD...NONE.
OH...NONE.
PA...NONE.
WV...NONE.
&&
$$
