FXUS61 KPBZ 100213
AFDPBZ
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PITTSBURGH PA
913 PM EST WED DEC 9 2009
.SYNOPSIS...
MUCH COLDER AIR WILL MOVE INTO THE REGION OVERNIGHT INTO THURSDAY.
WINDS WILL BE GUSTY OVERNIGHT AND WILL SLOWLY DIMINISH BY LATE
THURSDAY. HIGH PRESSURE WILL BUILD IN FROM THE SOUTHWEST FOR THE
LATE WEEK.
&&
.NEAR TERM /UNTIL 7 AM THURSDAY MORNING/...
02Z 500MB ANALYSIS INDICATES A CLOSED LOW ACROSS NORTHERN MICHIGAN
WITH A BROAD TROUGH. AT THE SURFACE...A 977MB LOW CENTERED OVER LAKE
HURON...WITH A 1020MB HIGH ACROSS THE SOUTHERN PLAINS. A COLD FRONT
EXTENDS SOUTHEASTWARD FROM THE LOW ACROSS CENTRAL PA AND SOUTHWARD
INTO THE CAROLINAS. A TIGHT PRESSURE GRADIENT HAS SETUP ACROSS
THE LOWER GREAT LAKES AND OHIO VALLEY. WINDS HAVE BEEN WEAKENING
OVER THE PAST FEW HOURS...THUS THE HIGH WIND WARNING HAS BEEN
CANCELLED. SOUTHWESTERLY WINDS ARE STILL GUSTING AT 30 TO 40 MPH
ACROSS THE AREA. COLD AIR ADVECTION CONTINUES BEHIND THE
FRONT...WITH SNOW SHOWERS DIMINISHING AND TEMPERATURES DROPPING
RAPIDLY INTO THE LOWER TO MID 30S ACROSS THE AREA.
TONIGHT...COLD AIR ADVECTION WILL CONTINUE ACROSS THE AREA BEHIND THE
COLD FRONT AS THE SURFACE LOW LIFTS NORTHEASTWARD INTO EASTERN
CANADA. THE TIGHT PRESSURE GRADIENT WILL CONTINUE TO LOOSEN UP
SOMEWHAT...ALLOWING WINDS TO STAY BELOW SUB-ADVISORY VALUES THROUGH
DAWN. VORT ENERGY ALONG THE BASE OF THE 500MB TROF ALONG WITH COLD
AIR ADVECTION WILL ALLOW FOR THE CHANCE OF SNOW SHOWERS INTO THE
PRE-DAWN HOURS THURSDAY...ESPECIALLY WITH UPSLOPING ACROSS THE
RIDGES. TEMPERATURES WILL BE NOTICEABLY COLDER FOR OVERNIGHT
LOWS...WITH VALUES 5 TO 10 DEGREES BELOW NORMAL ACROSS THE AREA.
WITH GUSTY WINDS....WIND CHILL VALUES WILL BE IN THE SINGLE DIGITS
TO NEAR ZERO AROUND DAWN THURSDAY.
&&
.SHORT TERM /7 AM THURSDAY MORNING THROUGH SATURDAY/...
SCATTERED UPSLOPE/LAKE ENHANCED SNOW SHOWERS WILL CONTINUE FOR
THE NORTH/RIDGES. WINDS WILL GRADUALLY DECREASE...BUT REMAIN
15-20 MPH WITH GUSTS TO 30 MPH OR SO THROUGH THURSDAY. ANOTHER
CONCERN WILL BE LOW WIND CHILL VALUES THURSDAY NIGHT/EARLY FRIDAY.
GIVEN WINDS OF 10-20 MPH AND TEMPERATURES OF 10-15 ABOVE ZERO...WIND
CHILL VALUES WILL RANGE FROM ZERO TO 5 BELOW FOR THE LOWLANDS...AND
-5 TO -10 FOR THE HIGHER ELEVATIONS. THUS...WILL NOT ISSUE A WIND
CHILL ADVISORY FOR NOW. LOW AMPLITUDE RIDGING ALOFT WILL RESULT
IN MAINLY DRY CONDITIONS FOR FRIDAY/SATURDAY WITH LESS WIND...ALTHOUGH
TEMPERATURES WILL REMAIN SIGNIFICANTLY BELOW NORMAL.
&&
.LONG TERM /SATURDAY NIGHT THROUGH WEDNESDAY/...
SURFACE HIGH PRESSURE WILL SLIDE EAST OF THE REGION SATURDAY NIGHT.
A WEAK SYSTEM PASSING TO OUR SOUTH WILL THEN BRING AN INCREASE IN
MOISTURE AND A SMALL CHANCE OF RAIN AND SNOW SHOWERS SATURDAY NIGHT
AND SUNDAY.
THE NEXT COLD FRONT APPROACHING FROM THE WEST WILL BRING SCATTERED
POPS FOR SNOW SHOWERS AND SNOW SHOWERS MIXED WITH RAIN SOUTH MONDAY
NIGHT AND TUESDAY.
SURFACE RIDGE WILL BUILD BACK INTO THE REGION WEDNESDAY WITH MAINLY
DRY CONDITIONS EXPECTED.
TEMPERATURES ARE EXPECTED TO BE WITHIN A FEW DEGREES OF NORMAL FOR
THE EXTENDED PERIOD.
&&
.AVIATION /02Z THURSDAY THROUGH MONDAY/...
COLD FRONT EAST OF RIDGES WITH HIGHEST PEAK WINDS ABOUT 3 HOURS
AGO AND WINDS LOOK TO SLOWLY SUBSIDE THROUGH THE DAY THURSDAY.
GENERAL VFR WITH ONLY PATCHY MVFR STRATUS MAINLY NORTHERN
TERMINALS LATE TONIGHT EARLY MORNING AS LAKE MOISTURE GRAZES
AREA. WINDS WILL REMAIN NEAR 250 DEGREES THROUGH THURSDAY WITH
DIMINISHING TO 25KTS BY LATE DAY.
VFR CONDITIONS CAN BE EXPECTED AS HIGH PRESSURE BUILDS IN FRIDAY
AND MOVES EAST ACROSS THE REGION THROUGH SATURDAY NIGHT. A WEAK
SYSTEM PASSING TO OUR SOUTH WILL THEN BRING AN INCREASE IN
MOISTURE AND SCATTERED RAIN AND SNOW SHOWERS SATURDAY NIGHT AND
SUNDAY WITH THE POTENTIAL FOR MVFR/IFR RESTRICTIONS.
VFR CONDITIONS SHOULD PREVAIL MONDAY UNDER WEAK RIDGING.
&&
.PBZ WATCHES/WARNINGS/ADVISORIES...
MD...NONE.
OH...NONE.
PA...NONE.
WV...NONE.
&&
$$
