573  
FXUS61 KBGM 230047  
AFDBGM  
 
AREA FORECAST DISCUSSION  
NATIONAL WEATHER SERVICE BINGHAMTON NY  
747 PM EST MON JAN 22 2018  
   
SYNOPSIS
 
 
A STORM SYSTEM MOVING OUT OF THE OHIO VALLEY WILL SPREAD RAIN  
ACROSS NY AND PA OVERNIGHT INTO EARLY TUESDAY. COLDER AIR BEHIND  
THE FRONT WILL GENERATE LIGHT SNOW SHOWERS TUESDAY NIGHT INTO  
WEDNESDAY.  
 

 
   
NEAR TERM /THROUGH TUESDAY/
 
 
730 PM UPDATE...  
SMALL POCKET OF NORTHERN OTSEGO COUNTY HAS HAD TEMPERATURES  
HOLDING AROUND FREEZING, WITH WET ROADS AND EARLIER RAIN/DRIZZLE  
WHICH HAS NOW WANED. PATCHY ICE STILL POSSIBLE THERE FOR A TIME  
THIS EVENING INCLUDING RICHFIELD SPRINGS, CHERRY VALLEY, AND  
SPRINGFIELD LOCALES. THAT BEING SAID, READINGS ACROSS MOST OF  
NORTHEAST PA-CENTRAL NY ARE IN THE MID 30S-MID 40S, AND THAT  
WILL CONTINUE TO CREEP UP OVERNIGHT AHEAD OF THE APPROACHING LOW  
PRESSURE SYSTEM. RAINWISE, THINGS ARE NOW PRETTY QUIET THIS  
EVENING, BUT LEAD SHORTWAVE WILL BRING AN AXIS OF SHOWERS INTO  
THE AREA SHORTLY AFTER MIDNIGHT. THIS WILL BE FOLLOWED BY TAP OF  
DEEP MOISTURE RIDING IN STRONG SOUTH-SOUTHWESTERLY LOW LEVEL  
JET WHICH WILL RESULT IN BATCH OF MODERATE RAIN FOR THE AREA  
THROUGH TUESDAY MORNING; HEAVIEST FROM THE WYOMING VALLEY-  
POCONOS THROUGH CATSKILLS WHERE AMOUNTS MAY EXCEED THREE-  
QUARTERS OF AN INCH. IN ADDITION TO TWEAKING DETAILS OF THE  
ABOVE FEATURES, FORECAST WAS ALSO ADJUSTED TO MOVE UP THE SLIGHT  
CHANCE OF THUNDER TO MAINLY THE MORNING HOURS, ACROSS ROUGHLY  
THE SOUTHEAST HALF OF THE AREA. MODELS IN AGREEMENT FOR THE  
MORNING HOURS BEING THE TIME FRAME FOR MARGINAL INSTABILITY TO  
CROSS THE AREA ALONG AND JUST AHEAD OF THE INCOMING COLD FRONT.  
 
PREVIOUS DISCUSSION...  
HIGH ELEVATION DENSE FOG CONTINUES TO HOLD STRONG, AND THE  
CURRENT THINKING IS THE FOG WON'T BREAK UP UNTIL THE NEXT WAVE  
OF RAIN SHOWERS MOVES IN OVERNIGHT AND MIXES UP THE ATMOSPHERE.  
IN THE MEANTIME, THE VALLEYS WILL EXPERIENCE PATCHY, LIGHT FOG,  
WHILE AREAS OF DENSE FOG (1/4 MILE TO 1/2 MILE) WILL AFFECT THE  
HIGH ELEVATIONS.  
 
A CYCLONE MOVING OUT OF THE OHIO VALLEY INTO MICHIGAN WILL PULL  
ADDITIONAL WARM AND HUMID AIR INTO NY/PA OVERNIGHT. RAIN WILL  
OVERSPREAD THE REGION, ACCUMULATING AROUND 0.75 TO 0.90 INCHES  
OVERNIGHT. A NON- DIURNAL TEMPERATURE TREND IS FORECAST  
TONIGHT, WITH TEMPERATURES HOLDING STEADY OR POTENTIALLY RISING  
INTO THE LOWER-40S.  
 
THE COLD FRONT WILL PASS THROUGH ON TUESDAY. RAIN SHOWERS WILL  
CHANGE OVER TO SNOW SHOWERS OVERNIGHT, WITH LITTLE TO NO  
ACCUMULATION EXPECTED ACROSS MOST OF THE REGION. LAKE EFFECT  
COULD PRODUCE AROUND AN INCH OF NEW SNOW OVER NORTHERN ONEIDA  
COUNTY.  
 

 
   
SHORT TERM /TUESDAY NIGHT THROUGH THURSDAY/
 
 
SHEARED NW FLOW OFF THE LAKES WITH MARGINALLY COLD AIR WILL  
BRING SOME LAKE EFFECT SNOW SHOWERS INTO THE NY ZONES ON  
WEDNESDAY. AMOUNTS WILL BE LIGHT AND TEMPERATURES NEAR NORMAL.  
FOR THURSDAY, SOMEWHAT COLDER AIR ARRIVES AS THE UPPER TROUGH  
DEEPENS, BUT FLOW OFF THE LAKE WILL BE LESS FAVORABLE AS A  
SURFACE HIGH BUILDS IN. STILL THERE WILL BE A FEW LAKE EFFECT  
SNOW SHOWERS AND FLURRIES WELL INTO THE DAYTIME HOURS THURSDAY.  
 

 
   
LONG TERM /THURSDAY NIGHT THROUGH MONDAY/
 
 
HIGH PRESSURE BUILDS IN FOR FRIDAY AS THE UPPER HEIGHTS RISE.  
THIS WILL BE MILDER AIR INTO THE AREA AS THE SOUTHERLY FLOW  
INCREASES. DRY WEATHER CONTINUES INTO SATURDAY AS THE SOUTHWEST  
FLOW STRENGTHENS INCREASING THE WARM ADVECTION CONTINUES. COLD  
FRONT PUSHES THROUGH SATURDAY NIGHT, FOLLOWED BY COLDER AIR FOR  
SUNDAY. EXPECT WIDESPREAD SHOWERS ALONG AND AHEAD OF THE FRONT,  
WITH SHOWERS ENDING QUICKLY BEHIND THE FRONT AS RIDGING BUILDS  
IN.  
 

 
   
AVIATION /00Z TUESDAY THROUGH SATURDAY/
 
 
A BRIEF IMPROVEMENT IN CONDITIONS IS OCCURRING ACROSS THE  
TERMINALS AS SHOWERS SHIFT EAST AND FLOW INCREASES. IN GENERAL  
THROUGH AROUND 06Z, MVFR/VFR CONDITIONS ARE FORECAST WITH  
RESTRICTIONS DUE PRIMARILY TO VISIBILITY. AFTER 06Z CONDITIONS  
WILL DETERIORATE AGAIN AS A FRONTAL BOUNDARY BRINGS RAIN BACK  
INTO THE TERMINALS. CONDITIONS WILL FALL INTO THE IFR CATEGORY  
WITH POSSIBLY ALTERNATE MIN CONDITIONS AT KITH/KELM/KAVP. BY  
EARLY AFTERNOON THE FRONT WILL PASS AND CONDITONS WILL QUICKLY  
IMPROVE TO LOW VFR/MVFR.  
 
LOW LEVEL WINDS SHEAR WILL PERSIST UNTIL FRONTAL PASSAGE  
TUESDAY AFTERNOON WITH SOUTHERLY WINDS AROUND 35-40 KNOTS AT 2K  
FEET ABOVE GROUND LEVEL. SURFACE WINDS WILL BE EAST/SOUTHEAST  
OVERNIGHT AROUND 10 KNOTS BUT GUSTY ON THE HILLTOPS. WINDS SHIFT  
TUESDAY AFTERNOON TO THE SOUTHWEST AT 10 KNOTS WITH GUSTS TO 18  
KNOTS.  
 
OUTLOOK...  
 
TUESDAY NIGHT THROUGH WEDNESDAY...POSSIBLE CONTINUATION OF  
FLIGHT CATEGORY REDUCTIONS AND A CHANCE OF SHSN.  
 
THURSDAY THROUGH SATURDAY...VFR UNDER HIGH PRESSURE.  
 

 
   
HYDROLOGY
 
 
745 PM UPDATE...  
LOCALIZED FLOODING DUE TO ICE JAMS IS POSSIBLE MAINLY TUESDAY  
THROUGH TUESDAY NIGHT. WIDESPREAD RAIN WILL DEVELOP ACROSS THE  
REGION LATE TONIGHT THROUGH MIDDAY TUESDAY, WITH AMOUNTS  
RANGING FROM A QUARTER TO THREE QUARTERS OF AN INCH.  
TEMPERATURES WILL RISE OVERNIGHT TO 45-50 RANGE BY LATE TUESDAY  
MORNING. ALSO, THE SNOW PACK WATER EQUIVALENT GOING INTO THIS  
EVENT WAS GENERALLY AROUND 1 INCH OR LESS. SO, THE COMBINATION  
OF RAIN AND SNOWMELT RUNOFF WILL CAUSE RIVERS TO RISE WHICH MAY  
BREAK UP THE ICE CURRENTLY IN PLACE. THIS MAY RESULT IN JAMS  
DOWNSTREAM. THE MOST RAINFALL IS EXPECTED ACROSS THE SUSQUEHANNA  
RIVER BASIN IN NORTHEAST PA AND THE DELAWARE BASIN IN NY AND  
PA. HOWEVER, ICE JAMS CAN OCCUR ALONG ANY RIVERS IN OUR AREA.  
OVERALL, RAIN AMOUNTS, TEMPERATURES, AND SNOWMELT POINT TO AN  
ISOLATED THREAT OF ICE JAM FLOODING AT WORST. WITH EACH  
SUCCESSIVE MODEL SUITE RUN, THE AVERAGE FORECAST RAINFALL  
AMOUNTS ARE LESSENING BIT BY BIT. WE WILL CONTINUE TO MONITOR  
THE SITUATION CLOSELY, AND IF HIGHER RAINFALL AMOUNTS WERE TO  
APPEAR MORE LIKELY, A FLOOD WATCH COULD BE ISSUED.  
 

 
   
BGM WATCHES/WARNINGS/ADVISORIES
 
 
PA...NONE.  
NY...NONE.  
 

 
 

 
SYNOPSIS...DJP  
NEAR TERM...DJP/MDP  
SHORT TERM...DGM  
LONG TERM...DGM  
AVIATION...RRM  
HYDROLOGY...MDP  
 
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