000 FXUS61 KCTP 082033 AFDCTP AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE STATE COLLEGE PA 333 PM EST SUN FEB 8 2009 .SYNOPSIS... A WEAK FRONT WILL SWEEP THROUGH THE AREA TODAY BRINGING GUSTY WINDS AND SLIGHTLY COOLER TEMPERATURES FOR THE START OF THE NEW WEEK. HIGH PRESSURE WILL MOVE EAST OF THE REGION BY LATER MONDAY...PAVING THE WAY FOR A SERIES OF FRONTAL SYSTEMS THAT WILL KEEP US UNSETTLED FOR MUCH OF THE REMAINDER OF THE WEEK. && .NEAR TERM /UNTIL 11 PM THIS EVENING/... THE WINDS ARE SLOWLY DIMINISHING OVER WESTERN AREAS AND WILL BEGIN TO DO SO OVER EASTERN AREAS OVER THE NEXT SEVERAL HOURS. BY ABOUT 6 PM THE GUSTY WINDS SHOULD SETTLE DOWN AS HIGH PRESSURE BUILDS IN OVER THE REGION AND THE STRONG GRADIENT SHIFTS TO OUR EAST. TEMPERATURES SHOULD SLIDE INTO THE 20S AND 30S LATER THIS EVENINGS. MOSTLY CLEAR SKIES SHOULD DOMINATE IN THE SOUTH AND EAST. THE CLOUDS IN THE NORTHERN MOUNTAINS WILL SLOWLY ERODE EARLY TONIGHT. && .SHORT TERM /11 PM THIS EVENING THROUGH MONDAY NIGHT/... STRONG HIGH PRESSURE MOVES OVER THE REGION TONIGHT AND EARLY MONDAY. THIS SHOULD PROVIDE FOR A MOSTLY CLEAR NIGHT AND MOSTLY SUNNY DAY ON MONDAY. THIS SHOULD ALSO PROVIDE FOR LIGHT WINDS. OVERNIGHT LOWS SHOULD RANGE FROM THE TEENS IN THE COLDER AREAS OF THE NORTH THROUGH THE TWENTIES IN MOST OTHER LOCATIONS. SOME URBAN AREAS IN THE SOUTHEAST MIGHT REMAIN NEAR 30F. THE HIGH PRESSURE RETREATS TO OUR EAST MONDAY AFTERNOON AND THE UPPER-LEVEL RIDGE LINE SLIDES TO OUR EAST TOO. SOME HIGH CLOUDS COULD MOVE OVER THE REGION FROM WEST TO EAST AS THE RIDGE LINE ALOFT SHIFT EASTWARD. THE SURFACE WINDS WILL COME AROUND TO THE SOUTHWEST LATE IN THE DAY AND EVENING HOURS. && .LONG TERM /TUESDAY THROUGH SATURDAY/... MODELS AND ENSEMBLES OFFER A SIMILAR LARGE SCALE PATTERN EVOLUTION FOR THE UPCOMING WEEK...RESULTING IN AVERAGE TO BETTER THAN AVERAGE CONFIDENCE IN THE MEDIUM TO LONG RANGE PERIOD. HOWEVER...IT IS QUITE AN ENERGETIC WINTER FLOW REGIME FOR MUCH OF NOAM WITH INHERENT EMBEDDED SHORTWAVE TIMING DIFFERENCES THAT WILL LIKELY BECOME RESOLVED AT SHORTER TIME SCALES. IN SHORT...THIS PERIOD WILL INITIALLY BE DOMINATED BY ABOVE NORMAL WARMTH FOLLOWED BY A SHARP COLD FRONTAL PASSAGE AROUND MID WEEK. COLDER...NEAR NORMAL TEMPERATURES ARE FORECAST BY THE END OF THE PERIOD WITH A POTENTIAL WINTER WEATHER EVENT FOR THE WEEKEND. GUIDANCE REMAINS IN-SYNC WITH PREVIOUS RUNS SUSTAINING A MEAN TROUGH OVER THE WRN CONUS. STRONG...FAST-MOVG SHORT WAVES WILL ROTATE AROUND THE BASE OF THE TROUGH OVER SOCAL AND EJECT EWD INTO THE PLAINS/OH VLY/SERN U.S...WHERE THEY WILL INTERCEPT GOMEX MOISTURE. THIS PATTERN SUGGESTS A SEVERE WEATHER THREAT FROM THE PLAINS SWD INTO THE LWR MS VLY MON-TUE...EVENTUALLY SPREADING E OF THE MS INTO THE MID SOUTH/OH VLY WED. ENSEMBLE DATA CONTINUES TO SHOW A MORE SUPPRESSED H5 FLOW BY THE WEEKEND. AS FOR SOME DETAILS... WARM FRONT WILL LIFT N OF PA BY WEDNESDAY AFTN...PLACING THE REGION FIRMLY IN A WARM SECTOR COMPLETE WITH DEEP LYR SRLY FLOW ON THE WRN PERIPHERY OF A DEPARTING ATLC SFC HIGH. H5 HEIGHTS ARE FCST TO BE ABOVE NORMAL DOWNSTREAM OF A STG MID LVL TROUGH HEADING NEWD FROM THE SRN PLAINS. SOME LEAD SHORT WAVE ENERGY COMBINED WITH INC WARM ADV/LYR PWS INVOF OF A LINGERING LO LVL BNDRY SHOULD LEAD TO SOME SCTD RAIN/SHOWER ACTIVITY TUE/WED. IF PCPN WHERE TO ARRIVE EARLY TUE MORNING...FCST SFC TEMPS APPEAR TO BE COLD ENUF TO SUPPORT A VERY BRIEF PERIOD OF LIGHT FZRA ACROSS THE NCENT MOUNTAINS AND UPPER SUSQ VLY. DEWPOINTS WILL STILL BE RATHER LOW...AND INITIAL PCPN MAY HAVE DIFFICULTY REACHING THE SFC. AS PREVIOUSLY THOUGHT YESTERDAY...THE MAIN STORY WILL BE MILD/MUCH ABOVE NORMAL TEMPS /10-20F ABOVE CLIMO/ BASED ON MANUAL GUID BLEND. GEFS DATA CONTINUES TO SHOW AN ANOMALOUS /-2 TO -3SD/ SFC LOW PRES OCCLUDING OVER THE GRT LKS BY WED NGT...IN ASSOC WITH A DYNAMIC AND VIGOROUS SHORTWAVE TROUGH POISED TO TAKE ON A NEG TILT BEFORE SHEARING OUT BY EARLY THURSDAY. ANOMALIES IN THE KEY FCST FIELDS ALONG WITH MINIMAL SPREAD IN THE 2M TEMP PLUMES SUGGEST A RATHER HIGH CONFIDENCE IN A SIGNIFICANT/SHARP FRONTAL PASSAGE WED NGT. STG SLY LO LVL WINDS/HIGH PWS WILL SUPPORT A BRIEF PD OF MOD TO HVY RNFL AHEAD OF THE CLD FNT. SOUTH/SOUTH EAST PRE-FRONTAL LO LVL WINDS WILL BE GUSTY. HOWEVER...A HIGH WIND THREAT EXISTS IN THE WAKE OF THE COLD FROPA GIVEN STG ISALLOBARIC PRESSURE RISES AND CAA. BIG BUST POTENTIAL FOR THURSDAYS HIGH AS A STEADY TO NON-DIURNAL TREND IS IN ORDER WITH MUCH COLDER AIR SWEEPING INTO THE REGION FROM THE NORTH/WEST. MORE TYPICAL POST-FRONTAL REGIME SHOULD SUPPORT UPSLOPE SNOW/RAIN SHOWERS ACROSS THE ALLEGHENIES ON THUR...THEN TAPERING OFF FRI. BY THE END OF THE WEEK...THE FINAL...FLATTER SHORTWAVE WILL LOOK TO SPAWN A RELATIVELY WEAKER SFC LOW /COMPARED TO THE MID WEEK STORM SYS/ SOMEWHERE ACROSS THE SERN THIRD OF THE CONUS. LATEST SUITE OF 08/12Z MODEL AND ENSEMBLE GUID HAS CONSIDERABLY MORE SPREAD THAN YESTERDAYS RUNS...WITH THE OP GFS MORE PROGRESSIVE AND FURTHER SOUTH COMPARED THE ECMWF. THE GEFS LOOKS LIKE A BROAD COMPROMISE OF THE GFS/ECMWF WITH A LOW OFF OFF CAPE HATTERAS NC AT 15/00Z. HPC PROGS FAVOR THE ECMWF SOLN...WHICH IS MUCH MORE FAVORABLE FOR SNFL OVER PA GIVEN A LOW TRACK ACROSS CENTRAL VA. && .AVIATION /20Z SUNDAY THROUGH FRIDAY/... THE STRONG AND GUSTY NORTHWEST WINDS BEHIND THE SURFACE COLD FRONT HAVE ALREADY BEGUN TO DECREASE IN INTENSITY OVER WESTERN AREAS AND SHOULD DO THE SAME IN EASTER AREAS LATER THIS AFTERNOON OR EVENING. FLYING BEFORE 20Z TODAY BEWARE OF STRONG GUSTY WINDS ESPECIALLY EAST OF IPT-SEG-THV. WIND GUSTS 25-35KTS ARE LIKELY. IN THE WEST GUSTS ARE DROPPING OFF FAST...BUT STILL SOME AREAS OF 15-25KTS. MOSTLY VFR CONDITIONS THIS AFTERNOON SOME MVFR IN THE CLOUDS OVER THE WESTERN MOUNTAINS AND ALONG THE NY BORDER. HIGH PRESSURE SHOULD CLEAR THINGS OUT AND QUICKLY ALLOW THE WINDS TO SUBSIDE. THUS...VFR CONDITIONS AND LIGHT WINDS SHOULD DOMINATE THE FLYING REGION BY 0000Z. MONDAY LOOKS VFR AND LIGHT WINDS ALL DAY. THE COMING WEEK SHOWS POTENTIAL FOR A PERIOD OF LOW CIGS/VIS WITH STORM SYSTEM PASSING TO OUR WEST THEN A COLD FRONT. THUS A PERIOD OF IFR/MVFR WED-THU IS POSSIBLE. GUSTY WINDS BEHIND THE COLD FRONT AND EVEN SNOW SHOWERS COULD BE A PROBLEM THURSDAY. YET ANOTHER STORM SYSTEM COULD BE AT THE...HEART...OF THE MATTER ON 14 FEBRUARY (VALENTINES DAY). IF THIS SYSTEM VERIFIES WE COULD SEE LOW CIGS/VISBY SOMETIME FRIDAY INTO PERHAPS EARLY SUNDAY. && .CTP WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SYNOPSIS...LACORTE NEAR TERM...GRUMM SHORT TERM...GRUMM LONG TERM...STEINBUGL AVIATION...GRUMM