515 FXUS61 KBGM 110402 AFDBGM AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE BINGHAMTON NY 1102 PM EST FRI JAN 10 2014 .SYNOPSIS... A WARM...SOUTHWEST FLOW OF AIR WILL DEVELOP AHEAD OF A LOW MOVING THROUGH THE GREAT LAKES. LIGHT RAIN MOVING INTO THE AREA TONIGHT WILL ENCOUNTER TEMPERATURES NEAR FREEZING THIS EVENING SO SOME LIGHT ICING IS POSSIBLE...MAINLY EAST OF INTERSTATE 81. MUCH MILDER AIR AND RAIN IS EXPECTED SATURDAY AS THE LOW APPROACHES OUR AREA. && .NEAR TERM /UNTIL 6 AM SATURDAY MORNING/... 1055 PM UPDATE... ALTHOUGH RADAR RETURNS ARE LIGHT...LIGHT RAIN IS ON SCHEDULE AND OVER NEPA AND PARTS OF THE CATSKILLS NOW. KAVP REPORTED LIGHT RAIN LAST HOUR. WHILE SURFACE TEMPS WILL REMAIN ABOVE FREEZING FOR MOST OF THE AREA TONIGHT AND SLOWLY RISE...OUR NORMALLY COLDER SPOTS EAST OF I-81 ARE HANGING TOUGH. LAST HOUR KMSV WAS 30...WITH PLENTY OF NEAR 32 OR LOWER READINGS ACROSS WAYNE AND SULLIVAN COUNTIES. IT WILL BE IN THESE AREAS...ALONG WITH PIKE COUNTY...WHERE THE MOST PROLONGED PERIOD OF LIGHT FREEZING RAIN WILL BE. MEANWHILE FARTHER WEST SOME RETURNS ARE NOW SHOWING UP OVER WESTERN NY. SOME ISOLATED ICING CAN'T BE RULED OUT IN THE REST OF OUR ADVISORY AREA AS THIS MOVES THROUGH...BUT MOST LOCATIONS WILL BE JUST ABOVE FREEZING. THE PREVIOUS AFD IS BELOW. 640 PM UPDATE... WILL BE MAKING SOME TWEAKS TO THE SHORT TERM GRIDS TO SLOW THE ARRIVAL OF THE RAIN OVERNIGHT. THE RAIN THAT WILL BE IMPACTING US IS NOW OVER SOUTHEAST PA. WITH A MOVEMENT MORE OFF TO THE NORTHEAST THAN NORTH...IT SEEMS THAT THE BEST SHOT FOR PRECIP TO ARRIVE WHEN TEMPS ARE NEAR FREEZING WILL BE FROM NEPA INTO SULLIVAN COUNTY NY. I WILL LET THE CURRENT FREEZING RAIN ADVISORY STAND AS IS BUT OUTSIDE OF THE AREAS JUST MENTIONED...IT APPEARS THAT BY THE TIME THE RAIN ARRIVES...TEMPS WILL BE ABOVE FREEZING. WILL WAIT A FEW MORE HOURS TO SEE HOW CURRENT OBS PLAY OUT AND TALK TO SURROUNDING OFFICES BEFORE TRIMMING ANY OF OUR CURRENT ADVISORY. THE PREVIOUS AFD IS BELOW. MODEL GUIDANCE IS IN REMARKABLE AGREEMENT FOR THE OVERNGT HRS IN REGARDS TO TEMPS AND SUGGEST THAT SOME LGT FZRA IS PSBL...ESP EAST OF I81. QPF WILL BE LGT...ACTUALLY AIDING IS A LGT COATING AS HEAVIER RAIN WLD LIKELY WRM THE BNDRY LYR AND SFCS ABV FRZG. HAVE ELECTED TO ISSUE A LOW COST ADVISORY FOR THE PSBLTY OF LGT ICING THIS EVENING INTO THE EARLY MRNG. NON DIURNAL TEMPS WILL BRING TEMPS UP ENUF TO REMOVE THE ICING HAZARD. OTR CNCRN OVRNGT WILL BE THE PSBLTY OF FOG. WITH THE FRESH SNOW PACKA AND ICRSG LL MOISTURE TRAPPED BLO A STRONG INV...PTCHY FOG SEEMS LIKE A GOOD BET. && .SHORT TERM /6 AM SATURDAY MORNING THROUGH MONDAY/... NAM DVLPS A GOOD SLUG OF MOISTURE SAT NEAR THE SE ZONES AND UNDER THE UPR LVL JET DIVERGENCE. THAT HEAVIER RAIN COULD HIT THE POCONOS AND SRN CATS SAT AFTN. OTRW...LOOKING FOR JUST A QUICK PD OF MOD RAIN WITH THE FNTL PASSAGE. MAIN FLOOD THREAT WILL COME FROM ICE JAMS...NOT FROM HEAVY RAIN OR SNOW MELT. UNFORTUNATELY... THIS MAY BE JUST ENOUGH RUNOFF TO LIFT THE ICE AND MOVE IT...BUT NOT FLUSH IT OUT. FNLY...COULD BE SOME THUNDER ON SAT...ESP OVER THE SE ZONES BUT FELT THE CHANCE WAS LOW ENUF ATTM TO KEEP IT OUT OF THE GRIDS. CAA BEGINS LATE SAT AND CONTS INTO SUN...BUT THERE/S A REAL LACK OF COLD AIR FOR A CHANGE. H8 TEMPS BOTTOM OUT AT -6C BEFORE 12Z SUN. VERY LIMITED LE PSBL...PERHAPS ENHANCED BY THE UPR TROF PASSING THRU. WAA AND RDGG RETURN BEFORE THE END OF THE DAY SUNDAY. RDGG AND TRANQUIL WX CONTS THRU MON. APRCHG TROF AND SFC COLD FNT SHD HOLD OFF UNTIL EARLY IN THE XTNDD PD. && .LONG TERM /MONDAY NIGHT THROUGH FRIDAY/... 230 PM UPDATE... OVERALL...LONG TERM PERIOD WILL BE DOMINATED BY TROUGHY...YET PROGRESSIVE UPPER-LEVEL FLOW WHICH WILL YIELD THE PASSAGE OF SEVERAL MID-LEVEL DISTURBANCES. FROM THIS VANTAGE POINT...THE FIRST OF THESE SYSTEMS WILL MOVE ACROSS THE REGION DURING THE DAY ON TUESDAY...WITH COOLER AIR EXPECTED TO FILTER INTO THE AREA BY MIDWEEK AS COLD AIR ADVECTION ENSUES. AS A RESULT...EXPECT REDEVELOPING LAKE EFFECT SNOWS SHOWERS BY TUES NGT/EARLY WED...BEFORE WEAK UPPER RIDGING BUILDINGS IN BY THURSDAY. FOLLOWING THIS...NEXT FRONT EXPECTED TO PASS ON FRIDAY WITH ANOTHER ROUND OF LAKE EFFECT EXPECTED INTO EARLY NEXT WEEKEND. THOUGH THE GENERAL PATTERN IS AGREED UPON BY MOST EXTENDED RANGE MODELS...CURRENT RUNS STILL SHOW MINOR DIFFERENCES ON TIMING OF THE ABOVE LISTED FEATURES. AS A RESULT...HAVE MAINTAINED CHC POPS THROUGH MIDWEEK BEFORE AGAIN INCREASING POPS LATER IN THE PERIOD. TEMPS THROUGH THE PERIOD WILL REMAIN SLIGHTLY ABOVE NORMAL THROUGH THE WORK WEEK...BEFORE NOTICEABLY COOLER AIR MOVES IN BY THE WEEKEND FOLLOWING THE SECOND STORM SYSTEM. && .AVIATION /04Z SATURDAY THROUGH WEDNESDAY/... 00Z UPDATE... DEGRADING CONDITIONS EXPECTED TONIGHT AS STRENGTHENING MOIST SOUTHEAST TO SOUTH FLOW BRINGS CLOUDS AND EVENTUALLY SHOWERS. ALSO...TEMPERATURES AND DEWPOINTS WILL BE RISING OVERNIGHT...WHICH ALONG WITH GRADUAL MELTING OF FRESH COATING OF SNOW FROM EARLIER TODAY WILL PROMOTE DEVELOPMENT OF MIST AND LOW STRATUS FOR SEVERAL TERMINALS. EXPECTING MOST TERMINALS TO DEVELOP LOW END MVFR THEN IFR CIGS OVERNIGHT...EVEN LIFR CIG AT TIMES KBGM. IFR POTENTIAL MORE IFFY FOR KRME AND KSYR DUE TO FLOW HAVING A DOWNSLOPE COMPONENT INTO THOSE TERMINALS...THUS MVFR CIG EXPECTED TO BE PREDOMINANT LATER TONIGHT INTO SATURDAY. LIGHT ESE TO SSE WIND EXPECTED AT SURFACE OVERNIGHT...HOWEVER...AT ABOUT 2 KFT AGL FOR ALL TERMINALS...SSW JET WILL MAXIMIZE DURING THE 07Z-12Z WINDOW TO ABOUT 50-60 KTS...THUS LLWS HAS BEEN INCLUDED IN TAFS DURING THAT TIME PERIOD. IT COULD LINGER BEYOND 12Z BUT THAT POTENTIAL WILL BE FURTHER ASSESSED AND DID NOT YET INCLUDE IN TAFS. AFTER 12Z...SHOWER ACTIVITY WILL BE SPORADIC YET IFR TO LOW END MVFR CIGS WILL CONTINUE. COLD FRONT WILL SWEEP THROUGH SATURDAY AFTERNOON WITH SHOWERS AND ACCOMPANYING RESTRICTIONS AS WELL AS SLIGHT VEERING OF WIND. EVEN TERMINALS THAT MANAGE TO LIFT INTO LOW END MVFR DURING THE DAY SATURDAY WILL HAVE A GOOD CHANCE AT RETURNING TO AT LEAST IFR ALONG AND BEHIND THAT FRONT. OUTLOOK... SAT NIGHT THROUGH SUN...RESTRICTIONS IN POST FRONTAL LOW CIGS AND -SHRA...MIXING WITH -SHSN THROUGH SUN MRNG. SUN NIGHT THROUGH MON...PRIMARILY VFR. MON NIGHT THROUGH WED...RESTRICTIONS POSSIBLE IN -SHRA/SHSN. && .HYDROLOGY... 4 PM UPDATE... THE THOUGHTS REGARDING HYDROLOGIC RESPONSE HAVE CHANGED LITTLE TODAY. SPRING-LIKE WARMING IS EXPECTED THIS WEEKEND THROUGH MONDAY WITH A RAIN EVENT EXPECTED SATURDAY. FORECAST RAIN AMOUNTS ARE A TOUCH LOWER THAN PREVIOUS FORECASTS...ESPECIALLY ACROSS CENTRAL NY WHERE ABOUT ONE HALF TO THREE QUARTER INCHES IS EXPECTED. HEAVIEST AXIS OF RAIN IS STILL TARGETING NEPA WHERE OVER AN INCH IS POSSIBLE FOR THE POCONOS. SNOW MELT COULD ADD UP TO ANOTHER HALF INCH LIQUID TO THE RIVERS. SEVERAL FOOT WATER LEVEL RISES ARE LIKELY...BUT THE MAIN CONCERN IS ICE JAM FLOODING. ICE NETWORK REPORTS SUGGEST MAIN STEM RIVERS ARE MOSTLY OPEN...WITH THE EXCEPTION OF SOME OF THE COMMON BENDS AND NARROWS WHERE ICE CONGESTION HAS BEEN REPORTED. AN ACTIVE ICE JAM CONTINUES IN THE CITY OF ITHACA WHERE MINOR FLOODING IS OCCURRING. GIVEN EXPECTED CONDITIONS OVER THE WEEKEND...ICE IS LIKELY TO BREAK UP AND START MOVING. WHETHER OR NOT THERE WILL BE ENOUGH FLOW TO ACTUALLY PUSH THE ICE FLOES THROUGH THE BENDS...NARROWS AND BRIDGE AREAS IS IN QUESTION AT THIS TIME AND THIS IS THE MAIN THOUGHT REGARDING THE POSSIBILITY OF LOCALIZED FLOODING. OUTSIDE OF ICE CONCERNS...THE RAIN/SNOW RUNOFF ALONE IS NOT EXPECTED TO CAUSE FLOODING IN THE NATURAL CHANNELS. && .BGM WATCHES/WARNINGS/ADVISORIES... PA...FLOOD WATCH FROM SATURDAY AFTERNOON THROUGH SUNDAY EVENING FOR PAZ038>040-043-044-047-048-072. FREEZING RAIN ADVISORY UNTIL 3 AM EST SATURDAY FOR PAZ040-048- 072. NY...FLOOD WATCH FROM SATURDAY AFTERNOON THROUGH SUNDAY EVENING FOR NYZ009-015>018-022>025-036-037-044>046-055>057-062. FREEZING RAIN ADVISORY UNTIL 3 AM EST SATURDAY FOR NYZ009-018- 036-037-044>046-055>057-062. && $$ SYNOPSIS...DGM NEAR TERM...DGM/HEDEN SHORT TERM...DGM LONG TERM...CMG AVIATION...MDP HYDROLOGY...