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
-- Remove Highlighting --
-- Discussion containing changed information from previous version are highlighted. --
000 FXUS61 KPBZ 220124 AAB AFDPBZ AREA FORECAST DISCUSSION...UPDATED NATIONAL WEATHER SERVICE PITTSBURGH PA 924 PM EDT TUE OCT 21 2014 .SYNOPSIS... DAMP AND COOL WEATHER WILL CONTINUE UNTIL UPPER LOW PRESSURE SHIFTS EASTWARD DURING THE LATTER HALF OF THE WEEK. && .NEAR TERM /THROUGH WEDNESDAY/...
-- Changed Discussion --
930PM UPDATE...CONTINUE TO RELY ON LATEST SAT/RADAR IMAGES AND LATEST HRRR MODEL RUN TO PUT TOGETHER POPS FOR THE OVERNIGHT. SHOWER COVERAGE HAS BEEN SLOWLY DECREASING AS IT DRIFTS SOUTHWARD OVER EASTERN THIRD OF MY FA. LOOKS TO BE A SMALL UPPER LEVEL WAVE THAT IS DRIVING THE PRECIPITATION. TEMPS HAVE ALSO BEEN ADJUSTED WITH LATEST LAMP NUMBERS. PREVIOUS DISCUSSION... IMPRESSIVE CIRCULATION PRESENT ON CURRENT RADAR AS A DECAYING LOW- TOPPED MCV HAS STALLED NEAR JEFFERSON COUNTY PA. DESPITE ENHANCED RADAR REFLECTIVITIES ALONG THE NRN EDGE OF THE CIRCULATION...THE HIGHEST RAINFALL REPORTS RECEIVED HAVE BEEN AROUND 1/3" PER HR. EXAMINATION OF THE INDIVIDUAL RADAR SLICES REVEALS THAT A GOOD PORTION OF THE ENHANCEMENT IS DUE TO BRIGHT BANDING...WITH FREEZING LEVELS RIGHT AROUND 7KFT. LATEST WATER VAPOR IMAGERY SHOWS ANOTHER SW TROF SWINGING SOUTH THROUGH OHIO WITH AN ATTENDANT VORT MAX THROUGH SRN OHIO. THIS GENERATED LAKE ENHANCED RAIN SHOWERS OVER THE SRN SHORE OF LAKE ERIE THAT HAVE SINCE DE-TATCHED FROM THE LAKE AND HAVE CONGEALED WITH THE BACK EDGE OF THE AFOREMENTIONED CIRCULATION. THIS VORT WILL EFFECTIVELY CUT-OFF THE UPPER LOW AND ALLOW IT TO DRIFT RIGHT OVERTOP OF US. WITH COPIOUS AMOUNTS OF LLVL MOISTURE AND THE COLD POOL ALOFT...FURTHER DEVELOPMENT OF CONVECTIVELY DRIVEN RAIN SHOWERS ARE EXPECTED EAST OF LAKE-ENHANCED AXIS OF RAIN SHOWERS. TONIGHT THE UPPER LOW DRIFTS SOUTH OF THE AREA...ENHANCING NRLY FLOW ALOFT WRAPPING MOISTURE BACK AROUND THE SYSTEM. THE LLVL FLOW WILL REMAIN NWRLY ENABLING AN UPSLOPE COMPONENT...THUS WILL CONTINUE THE LIKELY POPS IN THE SE RIDGES. ELSEWHERE...MULTIPLE WEAK MID-LEVEL VORTS ARE PROGGED TO SWING AROUND THE PARENT LOW...AND SHOULD CONTINUE TO AID THE DEVELOPMENT OF LIGHT RAIN SHOWERS. KEEPING CHC POPS IN ACROSS MUCH OF THE CWA THROUGH WEDS MORNING. WITH TEMPS MODERATED BY CLOUD COVER AND SHOWER ACTIVITY...LARGE MODIFICATIONS WERE NOT NECESSARY. TAX
-- End Changed Discussion --
&& .SHORT TERM /WEDNESDAY NIGHT THROUGH FRIDAY/... NORTHWESTERLY AND NORTHERLY FLOW IN THE LOW AND MID LEVELS CONTINUE THROUGH WEDNESDAY NIGHT AND INTO THURSDAY AS LOW LEVEL SHEAR SLOWLY INCREASES. THIS SHOULD ALLOW FOR UNSTABLE UPSLOPE FLOW SHOWERS TO SLOWLY WIND DOWN DURING THE PERIOD. SOME CLEARING SHOULD START TO WORK ITS WAY FROM WEST TO EAST ACROSS THE AREA AS LAYER MOISTURE SLOWLY PEELS OFF TO THE EAST AS WELL. YESTERDAY`S GFS...AND NOW TODAY`S ECMWF AND GFS BOTH INDICATE A SOMEWHAT ANOMALOUS LOOKING SHORT WAVE TRACKING SOUTHEASTWARD DOWN THE FRONT FLANK OF THE UPPER RIDGE THAT BUILDS TOWARD THE AREA BY LATE IN THE WEEK. DEEP MOISTURE DOES NO SEEM PARTICULARLY EVIDENT WITH THIS SYSTEM...AND THE DEPTH OF THE SYSTEM IS NOT PARTICULARLY WELL AGREED UPON. GIVEN THE FACT THAT THE GFS HAS BEEN A BIT MORE CONSISTENT WITH THE FEATURE IN ITS RUNS...TIMING AND PLACEMENT CLOSER TO THE GFS WAS FAVORED...WHICH WILL LIKELY ALLOW FOR AN INCREASE IN CLOUDS LATE IN THE WEEK...AND A VERY VERY SLIGHT CHANCE OF A FLEETING SPRINKLE. OTHERWISE...TEMPERATURES CONTINUE THEIR SLOW TREND TO CREEP BACK TOWARD NORMAL. FRIES && .LONG TERM /FRIDAY NIGHT THROUGH TUESDAY/... BLDG RIDGING ACRS THE CNTRL CONUS WL SHIFT E THRU ERLY NXT WK KEEPING DRY WEA IN THE FCST. SEASONALLY COOL TEMPS ARE EXP TO PUSH ABV AVG LVLS BY ERLY NXT WK. && .AVIATION /02Z WEDNESDAY THROUGH SUNDAY/... ABUNDANT LOW LEVEL MOISTURE WILL KEEP THE REGION SOCKED IN WITH CLOUDS THROUGH MOST OF THE TAF PERIOD. AS THE UPPER LEVEL LOW SLOWLY ROTATES ACROSS...SCATTERED TO NUMEROUS LIGHT RAIN SHOWERS WILL CONTINUE THROUGH MUCH OF THE NIGHT. MANY OF THESE WILL CONCENTRATE ALONG THE RIDGES. MVFR TO IFR CONDITIONS ARE FORECAST AREAWIDE INTO MIDMORNING ON WEDNESDAY. CIGS COULD IMPROVE TO VFR BY LATE AFTERNOON ACROSS EASTERN OHIO AND WESTERN PA. WINDS WILL GENERALLY BE OUT OF THE NORTH AND NORTHWEST. .AVIATION /WEDNESDAY THROUGH SATURDAY/... DUE TO THE LARGE AND SLOW MOVING UPPER LEVEL LOW PRESSURE SYSTEM...PERIODIC RSTRNS COULD LAST THROUGH THURS IN SCATTERED SHRA. && .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.