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 211833 AFDPBZ AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE PITTSBURGH PA 233 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 --
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/... COLD MID LVLS WL PERSIST OVR THE REGION THROUGH WEDNESDAY DESPITE THE LOW CNTR SHIFTING TWD THE COAST. DESPITE A CONSIDERABLE REDUCTION IN POPS...SHWRS CHCS IN THE LOW THRESHOLD CONVECTIVE ENVIRONMENT WERE MAINTAINED WITH EMPHASIS OVR THE UPSLOPE AREAS ALNG THE I 80 CORRIDOR AS WELL AS THE RIDGES. THEREAFTER...WARMING ALOFT/LOWERING INVERSION IS FORECAST TO SUPPRESS PCPN CHCS ON THURSDAY...ALTHOUGH SLGT TO CHC NMBRS WERE KEPT OVR THE HIGHER ELEVATIONS IN COLLABORATION WITH NEIGHBORING WFOS. TRAILING SHRTWV IS PROGGED FOR A FRIDAY CROSSING OF THE REGION...BUT SOME CLDS ARE ALL THAT IS ANTICIPATED GIVEN THE LACK A THERMAL TROF ALOFT AS WELL AS SUFFICIENTLY DEEP MSTR. SHORT TERM TEMPS WERE TWEAKED USING BIAS CORRECTED GFS MOS TRENDS...BUT LITTLE CHANGE WAS NEEDED. && .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 /18Z TUESDAY THROUGH SUNDAY/... A LARGE AND VERY SLOW MOVING SYSTEM IS MOVING THROUGH THE GREAT LAKES AND ACROSS THE AREA OVER THROUGH WEDS. THE MOISTURE ASSOCIATED WITH THIS SYSTEM IS FOUND PRIMARILY IN THE LOW TO MID-LEVELS WITH AN EXPANSIVE CLOUD DECK AND LIGHT RAIN SHOWERS GENERATED...THUS MVFR-IFR CONDITIONS ARE EXPECTED AREA-WIDE THROUGH MID-MORNING WEDS. AS OF 15Z MOST TERMINALS HAVE IMPROVED TO MVFR...BUT ARE EXPECTED TO DIP AGAIN INTO IFR AND POSSIBLY LIFR TONIGHT WITH REDEVELOPMENT OF LOW CIGS. TAX .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.