041
FXUS61 KPBZ 161751
AFDPBZ
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PITTSBURGH PA
151 PM EDT WED OCT 16 2013
.SYNOPSIS...
A COLD FRONT WILL SLOWLY CROSS THE REGION TODAY. A LOW PRESSURE
SYSTEM WILL TRACK NORTHEAST ACROSS THE REGION THURSDAY.
&&
.NEAR TERM /THROUGH TONIGHT/...
WITH 945AM UPDATE...MADE ADJUSTMENTS TO TIMING OF SHOWERS. MOST
LOCATIONS WILL LIKELY SEE A BREAK IN SHOWERS BEFORE A SECOND LINE
WITH THE ACTUAL FRONT CROSSES A FEW HOURS LATER. EXTRAPOLATING THE
BACK EDGE OF THE PRECIPITATION DRIES ALL LOCATIONS OUT BY
SUNSET...BUT MODELS INDICATE THAT THE FRONT WILL SLOW DOWN DURING
ITS PASSAGE...CONTINUING RAIN INTO THE EVENING HOURS IN SOME
LOCATIONS. HAVE KEPT THUNDER MENTION IN THE FORECAST THIS
AFTERNOON FOR NOW...BUT WILL REEVALUATE AFTER VIEWING THE 12Z
MODELS. PREVIOUS DISCUSSION FOLLOWS.
A COLD FRONT WILL PASS OVER THE FORECAST AREA TODAY WITH ALL
LOCATIONS LIKELY TO SEE PERIODS OF PRECIPITATION THROUGHOUT THE
DAY. LATEST ANALYSIS PLACES THE COLD FRONT JUST INTO WESTERN
OHIO...WITH RADAR SHOWING LIGHT TO MODERATE SHOWERS AHEAD OF THE
FRONT EXTENDING AS FAR EAST AS PITTSBURGH AS OF 430 AM. THE BRUNT
OF PRECIPITATION IS EXPECTED ACROSS NORTHERN ZONES TODAY WHERE JET
DYNAMICS ARE MORE FAVORABLE...BUT IN GENERAL TOTAL PRECIP AMOUNTS
ARE EXPECTED TO BE RELATIVELY LIGHT WITH TOTALS AROUND 0.25 ON
AVERAGE ACROSS NORTHERN ZONES AND LESSER AMOUNTS TO THE SOUTH.
THERE WILL LIKELY BE A BREAK IN THE WEATHER AFTER THE INITIAL
PERIOD OF SHOWERS AHEAD OF THE FRONT...BEFORE RESUMING AS THE
FRONT PASSES THROUGH. THE ONLY NOTABLE CHANGE TO THE ONGOING
FORECAST IN THE NEAR TERM WAS THE INCLUSION OF ISOLATED
THUNDERSTORMS DURING THE AFTERNOON AND EARLY EVENING..WITH CAPE
VALUES RANGING FROM 250 TO 300J/KG AND EFFECTIVE SHEAR BETWEEN
25-30KTS. THE COLD FRONT WILL CONTINUE TO LINGER ACROSS THE RIDGE
COUNTIES OF PA/WV/MD...WITH RAIN REMAINING INTO WEDNESDAY EVENING.
SOME PARTIAL CLEARING IS EXPECTED ACROSS EASTERN OHIO
COUNTIES...BUT A WESTERLY WIND SHOULD PROVIDE ENOUGH MOISTURE OFF
LAKE ERIE TO KEEP CLOUDS ACROSS A MAJORITY OF THE FORECAST AREA.
&&
.SHORT TERM /THURSDAY THROUGH FRIDAY NIGHT/...
ON THURSDAY AFTERNOON/EVENING ANOTHER DISTURBANCE WILL QUICKLY
PASS OVER THE FORECAST AREA AND RESULT IN ANOTHER ROUND OF
SCATTERED SHOWERS. LATEST GUIDANCE SHOWS GOOD CONTINUITY WITH
PREVIOUS RUNS AND MINIMAL CHANGE WAS NEEDED HERE...WITH THE BULK
OF THE HEAVIEST RAINFALL FARTHER SOUTH AND EAST ACROSS WEST
VIRGINIA AND VIRGINIA. CONDITIONS LOOK TO BE MORE STABLE OVERALL
WITH THIS FEATURE AND LEFT OUT ANY MENTION OF THUNDERSTORMS. BY
FRIDAY WINDS WILL TURN WEST TO SOUTHWEST AND...SKIES SHOULD BEGIN
TO CLEAR OUT.
WEDNESDAYS COLD FRONT WILL FINALLY BRING WIDESPREAD FALL-LIKE
CONDITIONS. THURSDAY AND FRIDAY WILL LIKELY BE THE FIRST DAYS IN
OCTOBER WITH BELOW NORMAL HIGHS...WITH FORECAST HIGHS AROUND 60
AND CLIMATOLOGY IN PITTSBURGH BEING 63 DEGREES. LOWS WILL BE NEAR
NORMAL VALUES...IN THE LOW TO MID 40S.
&&
.LONG TERM /SATURDAY THROUGH WEDNESDAY/...
COLDER WEA IS ANTICIPATED NXT WEEK FOR THE UPR OH VALLEY REGION AS
MDLS HAVE BEEN CONSISTENT IN FORECASTS OF HIGH AMPLITUDE TROF
DVLPMNT OVR ERN NORTH AMERICA. CURRENT TIMING SUGGESTS CDFNT
PASSAGE ON SATURDAY ACCOMPANIED BY SHWRS...WITH SUBSEQUENT SHRTWVS
IN FLOW PRVDG REINFORCEMENT OF THE COOLING AIRMASS THROUGH THE
WEEK.
THE LONG TERM PROGNOSIS WAS THUS CONSTRUCTED VIA PERSISTENCE AND
USE OF WPC GUIDANCE TO FEATURE CHC POPS...WITH BREAKS FOR
EXPECTATIONS OF SHRTWV RIDGING...ACCOMPANIED BY TEMPS AOB THE
SEASONAL AVERAGES.
&&
.AVIATION /18Z WEDNESDAY THROUGH MONDAY/...
SHWRS AND WIDESPREAD RESTRICTIONS...INCLUDING IFR CIGS...CAN BE
EXPECTED AS A CDFNT MOVS OVR THE UPR OH VALLEY TDA. SHRTWV SPPRT IS
SHIFTING EWD...HENCE RAIN COVERAGE HAS DIMINISHED AND CIGS MAY
BRIEFLY IMPROVE...BUT FRONTAL PASSAGE IS NOT EXPECTED TO BE
DECISIVE WITH LOW PRES APPRCHG FM THE SOUTH...HENCE...REDETERIORATION
TO IFR WAS FORECAST FOR THE OVRNGT HRS. THAT SYSTEM IS EXPECTED TO
SPREAD MORE RAIN ACRS UPR OH TERMINALS ON THURSDAY.
OUTLOOK.../THURSDAY THROUGH SUNDAY/...
RSTRNS ARE LIKELY THU NGT AS LOW PRES COMPLETES A TRACK ACRS THE
AREA. RESTRICTION AND RAIN ARE PSBL AGAIN WITH A SATURDAY CDFNT.
&&
.PBZ WATCHES/WARNINGS/ADVISORIES...
MD...NONE.
OH...NONE.
PA...NONE.
WV...NONE.
&&
$$