875  
FXUS61 KALY 151744  
AFDALY  
 
AREA FORECAST DISCUSSION  
NATIONAL WEATHER SERVICE ALBANY NY  
1244 PM EST SAT DEC 15 2018  
   
SYNOPSIS
 
 
HIGH PRESSURE WILL RIDGE IN FROM SOUTHEAST ONTARIO THIS  
AFTERNOON WITH FAIR AND DRY WEATHER, AS TEMPERATURES WILL BE MILD  
FOR MID DECEMBER WITH A NORTH TO NORTHWEST WIND. THOSE WINDS WILL  
SLOWLY USHER IN COLDER AND DRIER AIRMASS TONIGHT. THEN A COMPLEX  
STORM WILL EVOLVE ACROSS THE MIDDLE ATLANTIC COASTLINE ON SUNDAY AND  
SPREAD A WINTRY MIXTURE ACROSS MOST OF THE REGION SUNDAY INTO SUNDAY  
NIGHT. A STRONG COLD FRONT WILL MOVE THROUGH MONDAY ACCOMPANIED BY  
SNOW SHOWERS AND POSSIBLE SQUALLS.  
 

 
   
NEAR TERM /THROUGH TONIGHT/
 
 
AS OF 1230 PM EST...HIGH CLOUDS ARE STREAMING IN ACROSS THE  
NORTHERN HALF OF THE FORECAST AREA WHERE SOME FILTERED PARTLY  
SUNNY CONDITIONS ARE LIKELY THIS AFTERNOON. FURTHER SOUTH OF THE  
I-90 CORRIDOR LOW CLOUDS ARE LINGERING WITH THE HIGH CLOUDS  
ABOVE THEM, SO IT WILL LIKELY BE MOSTLY CLOUDY/CLOUDY BUT STILL  
MILD AS THE COLDER AIR WILL GRADUALLY FILTER SOUTH LATE THIS  
AFTERNOON INTO TONIGHT. WE REMOVED THE POPS OVER THE SOUTHERN  
EXTREME OF THE FORECAST AREA BASED ON THE LATEST RADAR TRENDS,  
BUT DID INCLUDE SOME PATCHY FOG FOR A FEW MORE HOURS NEAR KPOU  
SOUTH AND EAST INCLUDING SOUTHERN LITCHFIELD COUNTY, CT.  
 
WE INCREASED TEMPERATURES BASED ON THE OBSERVATIONAL TRENDS WITH  
THE NORTH TO NORTHWEST WINDS, MAX TEMPS HAVE REACHED THE UPPER  
40S IN PORTIONS OF THE CAPITAL REGION/MID AND UPPER HUDSON  
VALLEY, SO WE COULD HAVE SOME READINGS AROUND 50F WHICH IS 10+  
DEGREES ABOVE NORMAL. HIGHS WILL BE IN THE UPPER 30S TO LOWER  
40S NORTH AND WEST OF THE CAPITAL REGION/GLENS FALLS AREA WITH  
MID 40S TO AROUND 50F SOUTH AND EAST, EXCEPT SOME UPPER  
30S/LOWER 40S OVER THE SOUTHERN GREENS. LOW LEVEL DEWPOINTS WILL  
BECOME INCREASING DRIER THROUGH THE AFTERNOON HOURS WHICH WILL  
LEAD INTO OUR FORECAST CHALLENGES IN THE SHORT TERM.  
 
TONIGHT, MAINLY DRY AND CALM FOR THE REGION AS WE WATCH UPSTREAM  
STORM OVER THE TENNESSEE VALLEY SLOWLY APPROACH WITH SURFACE  
CYCLOGENESIS OVER THE MID-ATLANTIC UNFOLD. NEAR/SHORT TERM  
GUIDANCE SUGGESTS THE CHANCES FOR PRECIPITATION MAY APPROACH  
THE I84 CORRIDOR LATE TONIGHT YET DPROG/DT IS A BIT SLOWER WITH  
THE ONSET DUE TO THE AFOREMENTIONED NORTHERLY FLOW WHICH  
CONTINUES TO FILTER IN DRIER LOW LEVEL AIR. SO WE WILL CUT BACK  
POPS FROM THE PREVIOUS FORECAST WITH THIS UPDATE. AS FOR  
PRECIPITATION TYPES, VERY COMPLEX DUE TO THAT NORTHERLY LOW  
LEVEL FLOW AND MILDER TEMPERATURES ALOFT. FORECAST SOUNDINGS AND  
THICKNESSES SUGGEST THE POTENTIAL OF SLEET AND FREEZING RAIN AS  
WET-BULB PROCESSES GET UNDERWAY. OVERNIGHT LOWS RANGE FROM THE  
TEENS ACROSS THE MOUNTAINS TO NEAR THE FREEZING MARK NEAR THE  
I84 CORRIDOR. THE LATEST 12Z NAM/GFS/HREF TRENDS INDICATE SOME  
MIXED PCPN MAY GET IN THE LOCATIONS SOUTH AND WEST OF THE  
CAPITAL REGION BEFORE DAYBREAK. SOME LIGHT FREEZING RAIN MAY BE  
POSSIBLE, AND ADVISORIES MAY BE NEEDED LATER.  
 

 
   
SHORT TERM /SUNDAY THROUGH SUNDAY NIGHT/
 
 
THE WORD 'COMPLEX' FOR PRECIPITATION TYPES AND THERMAL PROFILES  
CONTINUES TO BE USED AS THE 00Z GUIDANCE DOES NOT SOLIDIFY  
THINGS TOO MUCH. TRENDS IN THE OVERALL GUIDANCE HAS BEEN A  
LITTLE STRONGER WITH THE SURFACE LOW ALONG THE COAST AND A BIT  
CLOSER TO THE COAST AS WELL. HOWEVER, TEMPERATURES AND WET BULB  
PROFILES VARY GREATLY ACROSS THE REGION ALONG WITH PERIODS OF  
LIFT/OMEGA THAT WILL COMPLICATE PRECIPITATION TYPES EVEN  
FURTHER. WITH THAT SAID, THE ONSET OF WINTRY MIXTURE ADVANCES  
NORTHWARD THROUGH THE DAYLIGHT HOURS SUNDAY WITH THE BEST  
POTENTIAL FOR RAIN CLOSER TO THE I84 CORRIDOR. THE PRECIP  
INTENSITY SHOULD BE RATHER LIGHT THROUGH THE DAYLIGHT HOURS AS  
BROAD ISENTROPIC LIFT WILL COMMENCE THROUGH THE DAY. THIS WILL  
EVENTUALLY LEAD TOWARD WET-BULB PROCESSES TO OCCUR FOR MIXTURE  
TO SOME SNOW WEST OF THE HUDSON RIVER THROUGH THE AFTERNOON  
HOURS.  
 
BY NIGHTFALL, THE SURFACE LOW INTENSIFIES AND PASSES CLOSE TO  
THE BENCHMARK FOR PRECIPITATION TO SPREAD NORTHWEST ACROSS MOST  
OF THE REGION. AGAIN, COMPLEX THERMAL PROFILES FROM NORTHWEST TO  
SOUTHEAST AS SEEN IN CROSS SECTIONS WET BULB PROFILES ALONG WITH  
SURFACE TEMPERATURE IN THE LOW AND MID 30S. AFTER CLOSE  
COORDINATION AND UTILIZING PARTIAL THICKNESS AND TOP-DOWN  
TECHNIQUES, THE BEST POTENTIAL FOR ICE ACCUMULATION SEEMS TO BE  
AT OR ABOVE 1000 FEET, ESPECIALLY FOR PORTIONS OF THE CATSKILLS,  
BERKS AND SOUTHERN GREENS. WHERE LIFT BECOMES MAXIMIZED, THIS  
COULD BISECT THE DENDRITIC ZONE FOR A PERIOD OF TIME WHERE A  
PERIOD OF MODERATE SLEET AND SNOW MAY OCCUR ACROSS THE CENTER OF  
THE CWA. FURTHER NORTH AND WEST, THESE AREAS WILL LIKELY BE  
LIGHTER WITH PRECIPITATION AMOUNTS AND REDUCED IMPACTS. DUE TO  
RATHER LOWER CONFIDENCE IN PRECIP TYPES, WE WILL NOT ISSUE ANY  
HEADLINES WITH THIS UPDATE BUT WILL LIKELY BE NEEDED WITH FUTURE  
FORECAST UPDATES.  
 

 
   
LONG TERM /MONDAY THROUGH FRIDAY/
 
 
ARCTIC FRONTAL BOUNDARY AND ASSOCIATED UPPER LEVEL DISTURBANCE WILL  
BE MOVING THROUGH THE REGION FOR MONDAY. ALTHOUGH MOISTURE WILL BE  
SOMEWHAT LIMITED, STRONG FORCING AND STEEP LAPSE RATES ALOFT WILL  
PROMOTE THE DEVELOPMENT OF SCATTERED SNOW SHOWERS AND SQUALLS. IT'S  
POSSIBLE THAT SOME VALLEY AREAS COULD ALSO SEE RAIN SHOWERS, BUT  
WITH DRY LOW-LEVELS AND COLD TEMPS ALOFT, ANY PRECIP WILL ANY DECENT  
INTENSITY SHOULD FALL AS SNOW SHOWERS. SQUALLS MAY BRIEFLY LOWER  
VISIBILITY AND ALLOW FOR SLICK CONDITIONS (ESPECIALLY NORTH AND WEST  
OF THE CAPITAL REGION AND ACROSS THE HIGH TERRAIN). HIGHS WILL BE  
REACHED EARLY IN THE DAY, REACHING INTO THE MID TO UPPER 30S FOR  
VALLEY AREAS, BEFORE FALLING IN THE AFTERNOON BEHIND THE COLD FRONT.  
 
A FEW UPSLOPE AND LAKE-ENHANCED SNOW SHOWERS WILL CONTINUE INTO  
MONDAY NIGHT ACROSS THE HIGH TERRAIN, BUT THIS SHOULD END BY TUESDAY  
MORNING AS HIGH PRESSURE QUICKLY BUILDS INTO THE AREA FROM THE  
MIDWEST. LOWS ON MONDAY NIGHT WILL BE IN THE TEENS AND 20S WITH  
GUSTY NORTHWEST WINDS. HIGHS ON TUESDAY WILL BE NOTICEABLY COLDER  
THAN RECENT DAYS, WITH TEMPS ONLY IN THE 20S. IT WILL STILL BE A  
LITTLE BREEZY, ALTHOUGH THE WIND SHOULD BE DECREASING BY LATER IN  
THE DAY AS THE HIGH GETS CLOSER TO THE AREA.  
 
GOOD RADIATIONAL COOLING WILL SET UP FOR TUESDAY NIGHT WITH LIGHT  
WINDS AND MAINLY CLEAR SKIES. TEMPS LOOK TO FALL INTO THE TEENS,  
WITH SOME SINGLE DIGITS OVER THE ADIRONDACKS. DRY AND QUIET WEATHER  
WILL CONTINUE FOR WEDNESDAY, ALTHOUGH IT WILL BE A LITTLE MILDER,  
WITH HIGHS GENERALLY IN THE 30S.  
 
THE NEXT STORM SYSTEM WILL BE ARRIVING FOR LATE IN THE WEEK. A  
LARGE DIGGING TROUGH OVER THE MISSISSIPPI VALLEY LOOKS TO TAKE ON A  
NEGATIVE TILT AND EVENTUALLY CLOSE OFF. MEANWHILE, A SURFACE STORM  
DEVELOPING OVER THE DEEP SOUTH WILL LIFT NORTHWARD ACROSS THE  
APPALACHIANS FOR THURSDAY INTO FRIDAY. WITH THIS STORM TAKING ON  
MORE A WESTERLY TRACK (AS SHOWN IN THE 00Z ECMWF, GFS AND GGEM), OUR  
AREA WOULD BE ON THE WARMER EASTERN SIDE OF THIS STORM. ASIDE FROM  
A LITTLE WINTRY MIX OVER THE ADIRONDACKS AT THE INITIAL ONSET LATE  
THURSDAY, MOST OF THE PRECIP FOR THURSDAY NIGHT THROUGH FRIDAY WILL  
BE IN THE FORM OF RAIN, AS TEMPS ALOFT WARM UP CONSIDERABLY AND  
SURFACE TEMPS RISE INTO UPPER 30S TO UPPER 40S. THIS SYSTEM LOOKS TO  
TAP INTO PLENTY OF GULF AND ATLANTIC MOISTURE, SO SOME APPRECIABLE  
RAINFALL AMOUNTS COULD POTENTIAL OCCUR BASED ON THE CURRENT FORECAST  
TRACK, WHICH COULD BE SUBJECT TO CHANGE. BEHIND THE STORM, RAIN  
SHOWERS COULD BRIEFLY CHANGEOVER TO SNOW SHOWERS BEFORE ENDING  
ACROSS WESTERN AND HIGH TERRAIN AREAS FOR FRIDAY NIGHT INTO  
SATURDAY.  
 

 
   
AVIATION /18Z SATURDAY THROUGH THURSDAY/
 
 
A STORM SYSTEM PASSING BY TO THE SOUTH WILL ALLOW FOR PLENTY OF  
CLOUDS ACROSS OUR AREA TODAY BUT ANY PRECIP SHOULD STAY WELL  
SOUTH AND EAST OF THE REGION.  
 
SKIES WILL BRIEFLY CLEAR OUT THIS EVENING WITH MAINLY CLEAR  
SKIES, BUT SOME HIGH AND MID LEVEL CLOUDS WILL RETURN TO THE  
REGION AFTER MIDNIGHT. FLYING CONDITIONS LOOK TO VFR THROUGH THE  
OVERNIGHT.  
 
SOME LIGHT PRECIP MAY START TO MOVE TOWARDS KPOU BY  
DAYBREAK SUNDAY AND THEN EXPAND NORTHWARD THROUGHOUT THE MORNING  
HOURS. FLYING CONDITIONS WILL DETERIORATE FROM SOUTH TO NORTH  
FROM MID-MORNING INTO THE AFTERNOON, BUT ESPECIALLY BY THE END  
OF THE TAF FORECAST PERIOD AS A WINTRY MIX ENVELOPES THE REGION.  
PRECIPITATION TYPE IS STILL IN QUESTION SO HAVE ACCOUNTED FOR  
MULTIPLE P-TYPES IN THE CURRENT TAFS. HIGHEST IMPACT OF THE  
WINTRY MIX LOOKS LIKE IT WILL OCCUR LATE IN THE FORECAST PERIOD  
AND BEYOND.  
 
WINDS FROM THE WEST WILL CONTINUE DURING THE DAY AND EVENTUALLY  
SWITCH TO THE NORTH BY LATE IN THE DAY AROUND 5 KTS. WINDS WILL  
BECOME NORTH TO NORTHEAST OVERNIGHT AT 5 KTS OR LESS.  
 
OUTLOOK...  
 
SUNDAY NIGHT: HIGH OPERATIONAL IMPACT. LIKELY SN...FZRA...SLEET.  
MONDAY: MODERATE OPERATIONAL IMPACT. CHANCE OF SHRA...SHSN.  
MONDAY NIGHT: NO OPERATIONAL IMPACT. NO SIG WX.  
TUESDAY: NO OPERATIONAL IMPACT. NO SIG WX.  
TUESDAY NIGHT: NO OPERATIONAL IMPACT. NO SIG WX.  
WEDNESDAY: NO OPERATIONAL IMPACT. NO SIG WX.  
WEDNESDAY NIGHT: NO OPERATIONAL IMPACT. NO SIG WX.  
THURSDAY: NO OPERATIONAL IMPACT. NO SIG WX.  
 

 
   
HYDROLOGY
 
 
TEMPERATURES WILL REMAIN MILD FOR THE FIRST HALF OF THE  
WEEKEND.  
 
DRY WEATHER IS EXPECTED TODAY BEFORE SOME LIGHT MIXED PCPN  
MOVES INTO THE SOUTHERN EXTREME OF THE HYDRO SERVICE AREA  
SUNDAY MORNING. THE MIXED PCPN WILL EXPAND ACROSS THE REGION ON  
SUNDAY BEFORE TRANSITIONING BACK TO SNOW SUNDAY NIGHT WITH LIGHT  
ACCUMULATIONS OF ICE AND SNOW EXPECTED. TOTAL QPF FOR THIS  
EVENT WILL RANGE FROM A TENTH OF AN INCH OF LESS OVER THE  
NORTHERN PORTION OF THE HSA WITH A HALF TO THREE QUARTERS OF AN  
INCH OVER THE MID HUDSON VALLEY, SOUTHEAST CATSKILLS AND  
LITCHFIELD HILLS. SOME WITHIN BANK RISES ARE POSSIBLE ON THE  
MAIN STEM RIVERS DUE TO SOME RAIN, MIXED PCPN AND SNOW MELT, BUT  
FLOODING IS NOT EXPECTED AT THIS TIME (CAUTION STAGE FOR  
STEVENSON DAM WHICH IS REGULATED).  
 
A STRONG COLD FRONT MOVES THROUGH ON MONDAY WITH MUCH COLDER  
AIR MOVING INTO THE REGION FOR TUESDAY, AS FLOWS WILL CONTINUE  
TO LOWER DURING THE EARLY TO MIDDLE PORTION OF NEXT WEEK WITH  
SOME ICE BUILD UP POSSIBLE.  
 
FOR DETAILS ON SPECIFIC AREA RIVERS AND LAKES, INCLUDING  
OBSERVED AND FORECAST RIVER STAGES AND LAKE ELEVATIONS, PLEASE  
VISIT THE ADVANCED HYDROLOGIC PREDICTION SERVICE /AHPS/ GRAPHS  
ON OUR WEBSITE.  
 

 
   
ALY WATCHES/WARNINGS/ADVISORIES
 
 
CT...NONE.  
NY...NONE.  
MA...NONE.  
VT...NONE.  
 

 
 

 
SYNOPSIS...BGM/WASULA  
NEAR TERM...BGM/JLV/WASULA  
SHORT TERM...BGM  
LONG TERM...FRUGIS  
AVIATION...FRUGIS/JLV  
HYDROLOGY...BGM  
 
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