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
172
FXUS61 KPBZ 071722
AFDPBZ

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PITTSBURGH PA
1222 PM EST SUN FEB 7 2016

.SYNOPSIS...
LOW PRESSURE IS POISED TO SPREAD RAIN AND SNOW OVER THE REGION ON
MONDAY AND TUESDAY.

&&

.NEAR TERM /THROUGH TONIGHT/...
MID LVL CLDINESS HAS RAPIDLY DISSIPATED UNDR SHRTWV RIDGING...NO
OTHER CHANGES WERE NEEDED FOR THE NR TERM PD.

THE UPR OH REGION IS EXPECTED TO REMAIN DRY THROUGH MIDNGT WITH
RIDGING RIDGING BETWEEN WRN GREAT LAKES AND SERN COASTAL LOW
PRESSURE SYSTEMS.  TEMPERATURES WILL ONCE AGAIN BE ABOVE SEASONAL
AVERAGES.

THE WRN LOW WL BE THE PROBLEM FOR THE NXT FEW DAYS AS IT IS
FORECAST TO DEEPEN OVR THE MIDWEST AND PLAGUE THE ARE WITH BROAD
ASCENT...DEEP MOISTURE...WITH SHORTWAVE SUPPORT ROTATING ARND THE
CUTOFF LOW.

FOR TONIGHT...MOISTURE AND ASCENT VIA WARM ADVCTN AND WEAKLY
DIVERGENT FLOW ALOFT ARE LIKELY TO SUPPORT PRECIPITATION
DEVELOPMENT OVER WESTERN ZONES TOWARD MORNING...WITH EASTWARD
PROGRESSION AFTER DAYBREAK MONDAY AS PER SLOWER MDL CONSENSUS. AS
THAT SOLN SEEMS REASONABLE GIVEN SBSDNC ON THE WRN FLANK OF THE
EXPLODING SE COAST/WRN ATLANTIC LOW...HAVE ADJUSTED GRIDS FOR THAT
SCENARIO AND RETREATED FROM OVRNGT POPS.

PRECIP TYPE REMAINS AN ISSUE GIVEN THE AFOREMENTIONED WARM ADVECTION
AND LINGERING BOUNDARY LAYER WARMTH. EXPECT A SNOW-TO-RAIN OR A
PRIMARY SNOW SITUATION WITH MELTING AT THE SFC AS THE SYSTEMS COLD
FRONT PLOUGHS TOWARD THE I 77 CORRIDOR DURING THE PREDAWN HOURS.
GIVEN THE TEMP LIMITATIONS AND SLOWER PROGRESSION...ANY LIGHT
ACCUMULATION IS NOT EXPECTED TO BE PROBLEMATIC.

&&

.SHORT TERM /MONDAY THROUGH WEDNESDAY/...
THE MARGINAL TEMPERATURE PROFILE AND WARM BOUNDARY LAYER ON THE EASTERN
SIDE OF THE SYSTEM ARE LIKELY TO CONTINUE COMPROMISING SNOW
POTENTIAL AND PRECLUDE MUCH IN THE WAY OF ACCUMULATIONS THROUGH
MONDAY. HOWEVER...THE SYSTEMS FRONTAL PASSAGE WILL USHER IN A COLDER
AIRMASS MONDAY NIGHT AND ANY LINGERING RAIN SHOWERS...OR RAPIDLY
MELTING SNOW SHOWERS...WILL HAVE BETTER ACCUMULATION POTENTIAL AS
NIGHT FALLS.

FORTUNATELY...THE ENCROACHMENT OF THE MID/UPPER LOW CENTER SHOULD
SUFFICIENTLY WEAKEN THE WIND/FRONTOGENESIS POTENTIAL AND OVERALL
ASCENT FIELDS TO OFFSET THE IMPROVED TEMPERATURE PROFILE FOR
SNOW. THE FORECAST REMAINS OF PROLONGED SNOW SHOWER POTENTIAL
THROUGH TUESDAY WITH RELATIVELY MINOR ACCUMULATIONS. THE
EXCEPTION...AS ALWAYS...WILL BE THE RIDGES...WHERE OROGRAPHIC
SUPPORT SHOULD PROMOTE MORE SIGNIFICANT ACCUMULATION.

BY WEDNESDAY...THE CUTOFF LOW IS FORECAST TO BE FILLED/PHASED WITH
THE UPR OH UNDER THE AXIS OF A HIGH-AMPLITUDE ERN CONUS TROUGH.
SNOW SHOWER POTENTIAL WILL THUS CONTINUE AS INCREASINGLY COLDER
AIR IS POISED TO FLOW OVR THE REGION AS THAT AXIS SHIFTS EWD. IN
ADDITION...THE LATEST DETERMINISTIC TREND IS TO ROTATE A VORT
CENTER/SHORTWAVE INTO THE BASE OF THAT LOW. PRECIP PROBS WERE THUS
INCRSD FOR WEDNESDAY...CUMULATING IN CATEGORICAL NUMBERS FOR THE
HIGHER ELEVATIONS...BUT DRY ADVCTN AND INCREASING COLD IN THE
SNOW-SOURCE REGION SHOULD DEGRADE EFFICIENCY SO TOTALS WERE NOT
AMPED MUCH AT THIS STAGE OF THE FORECAST PROCESS.

&&

.LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY/...
THE AFOREMENTIONED UPPER TROUGHING PTN IS PROGGED TO CONTINUE
FUNNELING COLD AIR OVR THE AREA THROUGH THE WEEKEND. SUB AVG TEMPS
CAN BE EXPECTED WITH READINGS 10 TO 15 DEGREES UNDER THE NORMALS
LIKELY BY THE WEEKEND. THE I 80 CORRIDOR AND RIDGE ZONES WL HAVE
THE BETTER SNOW SHOWER POTENTIAL DURING THIS PERIOD GIVEN THE
COLD...OFF-THE-LAKES UPSLOPING FLOW.

THE LONG TERM WAS CONSTRUCTED USING THE SUPERBLEND GUIDANCE.

&&

.AVIATION /17Z SUNDAY THROUGH THURSDAY/...
VFR WILL CONT TDA ALTHOUGH MID LVL CLOUDS WL INCRS LATER AHD OF
AN APPROACHING COLD FRONT. MVFR/PATCHY IFR IN RAIN AND SNOW IS
EXPD FOR PORTS W OF PIT BY SUNRISE MON MRNG...WITH PCPN/CONDITION
DETERIORATION SPREADING E THRU THE DAY AS THE FRONT ADVANCES.

.OUTLOOK.../TUESDAY THROUGH FRIDAY/...
RESTRICTIONS CAN BE EXPECTED THROUGH THU WITH THE AREA UNDR UPR
TROFG.

&&

.PBZ WATCHES/WARNINGS/ADVISORIES...
MD...NONE.
OH...NONE.
PA...NONE.
WV...NONE.

&&

$$
15/07



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