March 16, 2013 Forecast Discussion

000
FXUS61 KALY 161147
AFDALY

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE ALBANY NY
745 AM EDT SAT MAR 16 2013

.SYNOPSIS…
ANOTHER WEAK SYSTEM WILL PASS JUST TO THE SOUTH OF THE REGION TODAY
WITH A CHANCE FOR SOME LIGHT SNOW. LATER TONIGHT…ANOTHER CLIPPER
TYPE SYSTEM WILL TRACK ACROSS THE REGION WITH SOME LAKE EFFECT
SNOW SHOWERS ACROSS THE ADIRONDACKS LATE TONIGHT INTO SUNDAY
MORNING. THEN A CANADIAN HIGH PRESSURE SYSTEM WILL BUILD INTO THE
REGION FOR LATTER HALF OF THE WEEKEND. A STORM SYSTEM APPROACHES
FOR EARLY NEXT WEEK.

&&

.NEAR TERM /UNTIL 6 PM THIS EVENING/…
AS OF 630 AM…MINOR CHANGES TO HOURLY GRIDS…OTHERWISE…LITTLE
CHANGES TO THE ONGOING FORECAST.

THE LAST BIT OF SNOW SHOWERS ON THE RADAR WAS WEAKENING
QUICKLY ACROSS THE CATSKILLS AND MID HUDSON VALLEY REGION. IT
APPEARS THIS LAST BIT OF SNOW WAS A SEEDER-FEEDER AND SOME ASSIST
WITH LOW LEVEL CONVERGENCE SEEN IN THE MESONETS THIS MORNING. THE
00Z SOUNDINGS FROM HERE…BUF AND DTX ALONG WITH THE IR SATELLITE
IMAGERY SHOW THE HIGHER LEVEL MOISTURE OVERRUNNING THE LOWER LEVEL
STRATUS THAT RESULTED IN SOME CLOUD SEEDING OF THE LOWER LEVELS TO
BRING ABOUT THE SNOW WE OBSERVED OVERNIGHT. THAT AFOREMENTIONED
LOW LEVEL CONVERGENCE HAS NOW WEAKENING HENCE THE FAST DIMINISHING
TRENDS. SO THE BALANCE OF THE OVERNIGHT PERIOD…HAVE DIMINISHED
POPS CONSIDERABLY. CLOUD COVER REMAINS PROBLEMATIC AS THE LOW
STRATUS IS SHOWING SIGNS OF BREAKING UP FURTHER BUT BEING REPLACED
BY AN INCREASE IN HIGH LEVEL MOISTURE. SO SOME PEAKS OF SUNSHINE
ARE EXPECTED THIS MORNING /HIGHS CHANCE FOR MORE SUNSHINE NORTH
AND EAST OF ALBANY/ BEFORE CLOUDS OVERTAKE THE ENTIRE REGION
THROUGH THE MORNING HOURS.

FOR THE DAYLIGHT HOURS…UPSTREAM H2O VAPOR IMAGERY REVEALS OUR
NEXT SHORT WAVE OVER THE STATE OF WISCONSIN AS OF 3 AM EDT.
REGIONAL MOSAIC RADAR REVEALS BANDS OF SNOW ACROSS THE LOWER GREAT
LAKES REGION AND TRACKING EAST-SOUTHEAST. EXPERIMENTAL HRRR
REFLECTIVITY FORECASTS SUGGEST THE BEST POTENTIAL FOR
PRECIPITATION WILL FALL MAINLY SOUTH OF I90 WITH SOME OF THOSE
BANDS MIGRATING NORTHWARD ACROSS THE REMAINDER OF THE CWA.
FURTHERMORE…500-300MB DIV Q VECTORS SUGGEST A LITTLE NORTHWARD
JOG POTENTIAL THIS AFTERNOON. SO THE HIGHER POPS FOR PRECIPITATION
WILL BE ACROSS PORTIONS OF THE CATSKILLS…MID HUDSON VALLEY AND
INTO PORTIONS OF LITCHFIELD COUNTY. BOUNDARY LAYER TEMPERATURES
WILL ONCE AGAIN OFFER A MIXTURE OF RAIN/SNOW FOR VALLEY LOCATIONS
AND MAINLY SNOW FOR THE HIGHER TERRAIN. AMOUNTS WILL REMAIN RATHER
LIGHT WITH VALUES UP TO 1 INCH EXPECTED.

HIGH TEMPERATURES TODAY WE WILL STAY ON THE COOLER SIDE OF THE
GUIDANCE GIVEN THE CLOUD COVER AND THE CHANCE FOR PRECIPITATION.

&&

.SHORT TERM /6 PM THIS EVENING THROUGH MONDAY/…
IN THE WAKE OF THE SOUTHERN TRACK OF THE SYSTEM…CHANCES OF
PRECIPITATION WILL DIMINISH. HOWEVER…NEXT UPSTREAM CLIPPER TYPE
SYSTEM WAS CROSSING OVER LAKE WINNIPEG AROUND THE PERIPHERY OF THE
HUDSON BAY LOW. RATHER POTENT MID LEVEL JET /AOA 100KTS/ WILL
ACCOMPANY THIS COLD FRONT WITH A HEALTHY 1.5PVU ANOMALY. THIS
FRONT WILL BE MORE OF AN ARCTIC BOUNDARY AS TEMPERATURES IN THE
WAKE OF THIS BOUNDARY AT H850 ARE BELOW -20C FOR MID MARCH. THIS
BOUNDARY PER THE NCEP MODEL SUITE AND INTERNATIONAL GUIDANCE
SUGGEST A FROPA CLOSE TO 12Z SUNDAY. LAKE ONTARIO CONTRIBUTIONS
ARE EXPECTED TO INCREASE AS THOSE DELTA T/S INCREASE AND INVERSION
HEIGHTS BETWEEN 7-8K FEET. FOR THE WESTERN MOHAWK VALLEY
ADIRONDACKS…WE WILL RAISE POPS BACK INTO THE CHC-SCT CATEGORY
AND LEAVE THE SLIGHT CHANCE IN PLACE FOR THE REMAINDER OF THE
CWFA.

A RATHER BRISK AND CHILLY DAY SETTING UP ON SUNDAY AS THAT ARCTIC
BOUNDARY SLIDES QUICKLY EAST. FAVORABLE UPSLOPE AREAS COULD STILL
EXPERIENCE SOME LIGHT SNOW SHOWERS/FLURRIES AS THE ATMOSPHERE
SQUEEZES OUT RESIDUAL LOW LEVEL MOISTURE. MIXING LAYER HEIGHT
FORECASTS POINT TOWARD MIXING DOWN MID 20KTS WINDS AS TEMPERATURES
WILL STRUGGLE TO GET OUT OF THE 20S FOR THE HIGHER TERRAIN AND
LOW-MID 30S FOR VALLEY LOCATIONS WITH WIND CHILLS INTO THE TEENS
AND MIDDLE 20S FOR MANY AREAS.

SUNDAY NIGHT…LARGE CONSENSUS THAT RIDGING AT THE SURFACE AND
ALOFT WILL RESULT IN CLEAR SKIES AND LIGHT WINDS. NEARLY IDEAL FOR
RADIATIONAL COOLING AND WE WILL CONTINUE TO FAVOR COOLER THAN
GUIDANCE FOR OVERNIGHT LOWS WHERE SINGLE DIGITS AND TEENS WILL BE
COMMON.

MONDAY WILL BE THE DAY OF TRANSITION AS THAT SURFACE HIGH SLIDES
OFF THE NEW ENGLAND COAST AS POTENT NORTHERN PLAINS AND MID WEST
SYSTEM UNFOLDS. ISENTROPIC LIFT QUICKLY INCREASES FROM SOUTH TO
NORTH AS CLOUDS AND THE CHANCE FOR RAIN/SNOW INCREASES. THE BEST
CHANCE FOR PRECIPITATION WILL BE MAINLY SOUTH AND WEST OF THE
CAPITAL DISTRICT.

&&

.LONG TERM /MONDAY NIGHT THROUGH FRIDAY/…
AT THE START OF THE EXTENDED PERIOD…A COMPLEX STORM SYSTEM WILL
BE IMPACTING THE FORECAST AREA. AS A SFC STORM MOVES TOWARDS THE
CENTRAL GREAT LAKES…ANOTHER LOW PRESSURE CENTER WILL DEVELOP
ALONG THE STORM/S TRIPLE POINT ACROSS THE MID ATLANTIC REGION ON
MONDAY EVENING. THIS STORM WILL BECOME THE PRIMARY LOW…AS IT
RAPIDLY INTENSIFIES AND TRACKS RIGHT ALONG THE COASTAL PLAIN OF
THE NORTHEAST US FOR MONDAY NIGHT INTO TUESDAY. THE 00Z ECMWF
CONTINUES TO SHOW THAT THERE WILL BE JUST ENOUGH COLD AIR IN
PLACE…WHICH COULD ALLOW FOR A MODERATE TO HEAVY SNOW ACROSS MUCH
OF THE REGION. THE 00Z GGEM AGREES WITH THIS SCENARIO…AS WELL AS
SEVERAL MEMBERS OF THE 00Z GEFS. THE 00Z GFS IS A LITTLE BIT
WARMER…WHICH WOULD IMPLY A SNOW TO RAIN SCENARIO FOR VALLEY
AREAS. EVEN WITH THE ECMWF SOLUTION…SOUTHERN VALLEY AREAS COULD
CHANGEOVER TO A WINTRY MIX OR RAIN BEFORE ENDING BY TUESDAY AFTN
OR EVE. THE LATEST GFS DOES APPEAR TO HAVE TRENDED SLIGHTLY COLDER
THAN IT/S PREVIOUS RUN. BECAUSE OF THIS…WE WILL WILL FAVOR THE
ECMWF SOLUTION FOR NOW…AND GO WITH CATEGORICAL POPS FOR MON
NIGHT/TUES AND FORECAST SNOW FOR MONDAY NIGHT…AND A SNOW/RAIN
MIX FOR VALLEY AREAS FOR TUESDAY MORNING INTO TUESDAY AFTN. WE
WILL CONTINUE TO MONITOR MODEL TRENDS…AND MAKE NOTE OF THE
POTENTIAL FOR SIGNIFICANT SNOW ACCUMULATION IN OUR HWO STATEMENT.

BEHIND THIS STORM…IT WILL REMAIN CHILLY ACROSS THE REGION FOR THE
DURATION OF THE WEEK. AN UPPER LEVEL TROUGH WILL BE SITUATED OVER
THE NORTHEAST…AND WITH CYCLONIC FLOW AND LAKE ENHANCEMENT…SOME
SNOW SHOWERS AND FLURRIES WILL BE POSSIBLE…MAINLY FOR NORTHERN AND
WESTERN PARTS OF THE AREA. MAX TEMPS WILL ONLY REACH THE 30S IN MOST
AREAS /20S ACROSS THE HIGH TERRAIN/…WHICH IS A GOOD 10 DEGREES
BELOW NORMAL FOR MOST PLACES. MIN TEMPS WILL GENERALLY BE IN THE
TEENS TO LOW 20S. THE UPPER LEVEL TROUGH MAY FINALLY BEGIN TO DEPART
ON SATURDAY…WITH TEMPS TRENDING BACK UP TOWARDS NORMAL.

&&

.AVIATION /06Z SATURDAY THROUGH WEDNESDAY/…
ALTHOUGH THE SKY WILL BEGIN THE DAY WITH JUST FEW-SCT
STRATOCU…CLOUD COVERAGE WILL INCREASE THROUGH THE MORNING HOURS.
BKN CIGS OF MID LEVEL CLOUDS WILL BE IN PLACE FOR THE LATE MORNING
THROUGH THE LATE EVENING HOURS…BUT FLYING CONDITIONS WILL BE
VFR…AS A CLIPPER SYSTEM PASSES TO THE SOUTH OF THE AREA…BUT
COULD BRING SOME SNOW SHOWERS TO KPOU. FOR NOW…JUST WENT WITH VCSH
THERE.

THE WIND WILL BE VARIABLE TO NW AROUND 5 KTS.

OUTLOOK…
SUN-MON AM…VFR. NO SIG WX.
MON PM-TUE…MVFR/IFR. RAIN/SNOW LIKELY.
WED…VFR. NO SIG WX.

&&

.FIRE WEATHER…
ANOTHER WEAK SYSTEM WILL PASS JUST TO THE SOUTH OF THE REGION TODAY
WITH A CHANCE FOR SOME LIGHT SNOW. LATER TONIGHT…ANOTHER CLIPPER
TYPE SYSTEM WILL TRACK ACROSS THE REGION WITH SOME LAKE EFFECT
SNOW SHOWERS ACROSS THE ADIRONDACKS LATE TONIGHT INTO SUNDAY
MORNING. THEN A CANADIAN HIGH PRESSURE SYSTEM WILL BUILD INTO THE
REGION FOR LATTER HALF OF THE WEEKEND. A STORM SYSTEM APPROACHES
FOR EARLY NEXT WEEK WITH A HIGH CHANCE FOR MORE THAN ONE HALF OF
AN INCH OF LIQUID EQUIVALENTS.

THEREFORE…NO FIRE WEATHER CONCERNS FOR THE NEXT COUPLE OF DAYS.

&&

.HYDROLOGY…
NO HYDROLOGICAL PROBLEMS EXPECTED THROUGH EARLY NEXT WEEK. ANY
PRECIPITATION WILL BE LIGHT AND MAINLY IN THE FORM OF SNOW SHOWERS
THROUGH THE WEEKEND.

THE CHANCE FOR A MORE SIGNIFICANT PRECIPITATION EVENT WILL OCCUR
LATE MONDAY THROUGH TUESDAY. THERE IS STILL MUCH UNCERTAINTY
REGARDING HOW MUCH OF THE PRECIPITATION WILL FALL AS RAIN OR SNOW
WITH THIS SYSTEM. HOWEVER…THERE IS A HIGH CHANCE FOR MORE THAN
ONE HALF OF AN INCH OF LIQUID EQUIVALENTS.

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
NEAR TERM…BGM
SHORT TERM…BGM
LONG TERM…FRUGIS
AVIATION…FRUGIS
FIRE WEATHER…BGM
HYDROLOGY…BGM

FOR THE LATEST UPDATES…PLEASE VISIT OUR WEBPAGE AT
WWW.WEATHER.GOV/ALBANY

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