Area Forecast Discussion
Issued by NWS

Current Version | Previous Version | Text Only | Print | Product List | Glossary On
Versions: 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50
-- Highlight Changed Discussion --
-- Discussion containing changed information from previous version are highlighted. --
000 FXUS61 KPBZ 220216 AFDPBZ AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE PITTSBURGH PA 916 PM EST SUN DEC 21 2014 .SYNOPSIS... MIDWESTERN LOW PRESSURE WILL BRING WARMER TEMPERATURES AND RAIN TO THE UPPER OHIO VALLEY REGION FOR THE FIRST HALF OF THE WEEK. SNOW SHOWER CHANCES WILL COME WITH PASSAGE OF THAT SYSTEMS COLD FRONT ON CHRISTMAS. && .NEAR TERM /THROUGH MONDAY/...
-- Changed Discussion --
WITH 915PM UPDATE...CONTINUED TO MAKE SKY COVER ADJUSTMENTS FOR LOW CLOUDS MOVING TO THE NORTH. AT THIS POINT APPEARS THAT LOW CLOUDS ARE CONTAINED TO MERCER/VENANGO COUNTIES...WITH SCATTERED HIGH CLOUDS ELSEWHERE. ALSO UPDATED HOURLY TEMPERATURE TRENDS AGAIN...AS TEMPERATURES HAVE DROPPED SLIGHTLY BELOW PREVIOUS FORECAST. A QUICK LOOK AT THE 00Z NAM/HRRR SHOW PRECIPITATION REMAINING SOUTH OF THE FORECAST AREA AS OF 15Z...DIMINISHING THE CHANCES THAT PRECIPITATION WOULD REACH GARRETT/TUCKER COUNTIES BEFORE SURFACE TEMPERATURES HAVE A CHANCE TO RISE ABOVE FREEZING. PREVIOUS DISCUSSION FOLLOWS. WARM ADVECTION BEGINS IN EARNEST OVERNIGHT...BRINGING H850 TEMPS ABOVE ZERO FOR THE SOUTHERN CWA BY 12Z MONDAY. SOME LOWER CLOUDS COULD BE REALIZED PRIOR TO 12Z ALONG EAST-FACING SLOPES IN GARRETT/TUCKER COUNTIES. GENERALLY LEANED TOWARDS THE WARMER TEMPERATURE GUIDANCE FOR LOWS. ON MONDAY...INVERTED TROUGH SETS UP ALONG THE CAROLINA COAST. WITH DEPARTING HIGH ACROSS NEW ENGLAND...A COLD AIR DAMMING SCENARIO LOOKS TO BE SETTING UP FOR THE EAST-FACING RIDGES. FOR MOST AREAS...IT WILL SIMPLY BE A MOSTLY CLOUDY DAY. BETTER MOISTURE SPINS AROUND THE INVERTED TROUGH TOWARDS THE SOUTHEAST CORNER OF THE CWA BEGINNING LATER MONDAY MORNING. WITH THE OVERNIGHT WARM ADVECTION ALOFT AND COLD AIR EXPECTED TO BE TRAPPED IN THE VALLEYS...A TEMPERATURE STRUCTURE IDEAL FOR FREEZING RAIN WILL BE PRESENT ACROSS GARRETT/PRESTON/TUCKER COUNTIES. HOWEVER...QPF WILL BE THE LIMITING FACTOR AS MOISTURE AND LIFT ARE TOO SHALLOW TO SUPPORT PRECIPITATION OF ANY SIGNIFICANCE. CANNOT JUSTIFY ANYTHING HIGHER THAN CHANCE POPS AT PRESENT. ONLY A COUPLE HUNDREDTHS OF AN INCH OF LIQUID ARE EXPECTED AT MOST. WILL NOT BE ISSUING ANY HEADLINES AT THE PRESENT TIME. SPS CAN BE USED IN THE MORNING IF THE THREAT INCREASES. CONTINUED WARM ADVECTION WEST OF THE RIDGES WILL PUSH MONDAY HIGH TEMPS AT LEAST SEVERAL DEGREES ABOVE NORMAL...WHILE TEMPS REMAIN IN THE 30S ALONG THE EASTERN CWA BORDER.
-- End Changed Discussion --
&& .SHORT TERM /MONDAY NIGHT THROUGH WEDNESDAY NIGHT/... UPPER TROUGH WILL AMPLIFY AND SLOWLY PIVOT EASTWARD DURING THIS TIME FRAME...BECOMING MORE NEGATIVELY TILTED WITH THE HELP OF A STRENGTHENING UPPER LEVEL JET BY LATE WEDNESDAY. EARLY ON...THERE STILL REMAINS SOME UNCERTAINTY IN REGARD TO THE AMOUNT OF PRECIP THAT WE WILL SEE ON TUESDAY...AS WE WILL BE PARKED IN BETWEEN THE BETTER MOISTURE FROM THE WEAK COASTAL SYSTEM...AND THE DEEPENING MOISTURE ASSOCIATED WITH THE COLD FRONT TO OUR WEST. IN ADDITION...S-SE WIND SHOULD HELP PROVIDE SOME DOWNSLOPING AND DRYING JUST EAST OF THE RIDGES IN PA/WV. WITH THIS IN MIND...OPTED TO STAY WITH THE CHANCE POPS FOR THE DAY TUESDAY. WILL INCREASE POPS OVERNIGHT AS THE LOW LEVEL JET STRENGTHS AND HELPS TO PULL MOISTURE FROM THE GULF NORTHWARD. WITH THE NEARLY NORTHWARD PROGRESSION OF THE DEVELOPING SURFACE LOW...BOTH THE ECMWF AND GFS SUGGEST THE BULK OF THE HEAVIEST RAIN WILL STAY JUST WEST OF THE FORECAST AREA...WITH THE BEST CHANCE FOR MODERATE RAIN TO BE AS THE COLD FRONT CROSSES WEDNESDAY NIGHT. THIS SHOULD LIMIT ANY FLOOD THREAT FOR THE PERIOD. STRONG WARM ADVECTION WILL BE ONGOING THROUGH THE ENTIRE TIME PERIOD. EVEN WITH CLOUD COVER...HIGH TEMPERATURES ON BOTH TUESDAY AND WEDNESDAY SHOULD BE WELL ABOVE SEASONAL VALUES WITH HIGHS LIKELY TO REACH THE MID 50`S. && .LONG TERM /THURSDAY THROUGH SUNDAY/... CDFNT PASSAGE WILL INITIATE SNOW SHOWER CHANCES ON CHRISTMAS...BUT LACK OF DEPTH TO THE COLD LYR...DRY ADVCTN IN THE MID LVLS ON THE SRN PERIMETER OF NWD DIGGING UPR LOW...AND RAPIDLY ENSUING WARM ADVCTN WL ENSURE A LACK OF SNOW COVER FOR CHRISTMAS. THE RMNDR OF THE LONG TERM PD IS PROGGED TO FEATURE SEASONAL TEMPS WITH A LATE WEEK COOLING TREND AS MDLS PROG A REAMPLIFYING FLOW PTN WITH ERN CONUS TROFFG. && .AVIATION /02Z MONDAY THROUGH FRIDAY/... GENL IMPROVEMENT TO VFR FOR ALL TAF SITES CAN BE EXPECTED FOR THE TAF PD AS SLY FLOW ALOFT INTENSIFIES OVR LINGER SFC HIGH PRES. OUTLOOK.../MONDAY THROUGH FRIDAY/... MIDWRN LOW PRES WL SPREAD RAIN AND RESTRICTIONS OVR AREA PORTS ON TUESDAY AND WEDNESDAY. IMPROVEMENTS ARE EXPECTED TO BE INITIATED LTR ON THURSDAY WITH DRY SHRTWV RIDGING. && .PBZ WATCHES/WARNINGS/ADVISORIES... MD...NONE. OH...NONE. PA...NONE. WV...NONE. && $$

USA.gov is the U.S. government's official web portal to all federal, state and local government web resources and services.