Forecast Discussions mentioning any of
"HRRR" "RAP" "RR" "RUC13" "RUC" received at GSD on 02/04/13
AREA FORECAST DISCUSSION
NWS ALBANY NY
929 AM EST SAT FEB 2 2013
.SYNOPSIS...
A CLIPPER LOW WILL APPROACH FROM THE LOWER GREAT LAKES
REGION WITH ISOLATED TO SCATTERED SNOW SHOWERS LATE THIS AFTERNOON
INTO THIS EVENING. ANOTHER CLIPPER WILL IMPACT THE REGION LATE
SUNDAY INTO SUNDAY NIGHT WITH SOME LIGHT SNOW AND CONTINUED BELOW
NORMAL TEMPERATURES TO OPEN NEXT WEEK. MUCH OF THE UPCOMING WEEK
WILL BE DRY WITH SEASONABLY CHILLY TEMPERATURES.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
AS OF 929 AM EST...A BAND OF LAKE EFFECT SNOW HAS DEVELOPED OFF
LAKE ONTARIO...BUT IS REMAINING NORTHWEST OF OUR FORECAST AREA
ACROSS THE TUG HILL PLATEAU AND INTO THE ST. LAWRENCE VALLEY.
WITH A SW FLOW TRAJECTORY IN PLACE...THIS BAND SHOULD REMAIN JUST
NORTHWEST OF OUR FORECAST AREA TODAY. THE 240 DEGREE TRAJECTORY
IS EXPECTED TO IMPACT LOCATIONS JUST NORTH AND WEST OF THE WRN
DACKS. THE LATEST 12Z ALY HIRES WRF COMPOSITE REFLECTIVITY...AND
3-KM HRRR SHOW LITTLE IMPACT IN OUR AREA TODAY. WE KEPT SOME HIGH
CHC AND LIKELY POPS NORTH OF OLD FORGE IN HERKIMER COUNTY...AND
FAR NW HAMILTON COUNTY...BUT THE CORE OF THE BAND SHOULD REMAIN TO
THE NW.
A WEAK CLIPPER LOW IS MOVING ACROSS THE OHIO VALLEY THIS MORNING
AS SEEN VIA THE WATER VAPOR LOOP. THIS SYSTEM WILL APPROACH FOR
THE LATE AFTN AND EARLY EVENING HOURS. THERE IS LITTLE MOISTURE
FOR THIS SYSTEM TO WORK WITH...AND WITH THE SYSTEM BEING RATHER
WEAK...FORCING WILL BE LIMITED. VERY DRY LOW LEVELS WILL ALLOW FOR
SOME OF THE LITTLE MOISTURE THIS SYSTEM HAS TO BE LOST AS VIRGA.
WE WILL GO WITH SLIGHT CHC TO CHC POPS FOR MOST OF THE AREA DURING
THE AFTN/EARLY EVENING TO ACCOUNT FOR SOME LIGHT SNOW SHOWERS
ACTIVITY...WITH THE BEST CHC OF SEEING ACTIVITY ACROSS WESTERN
AREAS AND THE HIGH TERRAIN.
DESPITE WEAK LOW TO MID LEVEL WARM ADVECTION...H850 TEMPS WILL
STILL BE -12C TO -16C FROM SOUTH TO NORTH OVER THE CWA. EXPECT
HIGHS TO BE 5 TO 10 DEGREES BELOW NORMAL WITH HIGHS IN THE MID TO
U20S IN THE CAPITAL DISTRICT...THE MID HUDSON VALLEY...AND CT
VALLEY. EXPECT TEENS TO L20S OVER THE MTNS...LAKE GEORGE
REGION...W-CNTRL MOHAWK VALLEY...SRN VT...AND THE LITCHFIELD HILLS.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH MONDAY NIGHT/...
TONIGHT...THE FIRST OF TWO CLIPPERS PASSES SOUTH OF THE REGION
WITH SCT SNOW SHOWERS/LIGHT SNOW ENDING FROM NORTH TO SOUTH.
EXPECT MAINLY COATINGS TO A HALF AN INCH AROUND THE REGION.
PORTIONS OF THE ERN CATSKILLS...AND WRN ADIRONDACKS COULD SEE
AROUND AN INCH OR SO. THE FLOW VEERS TO THE W/NW AGAIN WITH THE
UPPER LEVEL TROUGH OVER CNTRL-ERN CANADA CONTINUING TO THE DRIVE
THE WX OVER NY AND NEW ENGLAND. MIN TEMPS WERE BLENDED FROM THE
MET/MAV GUIDANCE WITH SINGLE DIGITS NORTH OF THE CAPITAL
REGION...AND THE MOHAWK VALLEY...AND TEENS FROM THE I-90 CORRIDOR
SOUTH AND EAST.
SUNDAY-SUNDAY NIGHT...ANOTHER LULL IS BRIEFLY EXPECTED IN THE PARADE
OF SHORT-WAVES/CLIPPERS IN THE W/NW FLOW ALOFT SUNDAY MORNING. THE
GUIDANCE HAS TRENDED A BIT SLOWER WITH THE NEXT CLIPPER. SOME
SLIGHT CHC POPS WERE PUT IN DURING THE LATE MORNING WEST OF THE
HUDSON RIVER VALLEY...AND THEN CHC POPS WERE PUT IN EVERYWHERE IN
THE PM INTO THE EVENING. THIS CLIPPER AND ITS ASSOCIATED SHORT-
WAVE MOVE ACROSS THE CNTRL-ERN GREAT LAKES INTO THE REGION. THEIR
IS SOME PRONOUNCED CYCLONIC VORTICITY ADVECTION WITH IT. THE
DISTURBANCE WILL PRODUCE A ROUND OF LIGHT SNOW FOR THE REGION WITH
GENERALLY A DUSTING TO AN INCH OR SO IN MOST LOCATIONS. THE SHORT-
WAVE ENERGY WITH THIS CLIPPER WILL LIKELY PHASE WITH A STORM EAST
OF THE GULF OF MAINE SUNDAY NIGHT. THE STORM WILL INTENSIFY AND
DEEPEN NEAR THE CANADIAN MARITIMES. SOME WESTERLY UPSLOPE OR LAKE
EFFECT SNOWFALL MAY IMPACT THE SRN GREENS AND WRN DACKS. WE HAVE
1-4" OF SNOW SUNDAY TO SUNDAY NIGHT IN THESE AREAS. HIGHS WILL
RANGE FROM THE 20S TO L30S ACROSS THE REGION...TO SINGLE DIGITS TO
TEENS FOR LOWS.
MONDAY-MONDAY NIGHT...THE WORK WEEK WILL OPEN WITH BLUSTERY AND COLD
CONDITIONS...AS A DEEPENING AND INTENSIFYING LOW PRESSURE SYSTEM
MOVES TOWARD LABRADOR...AND ARCTIC HIGH PRESSURE BUILDS IN FROM
THE GREAT LAKES REGION AND ONTARIO. W/NW WINDS OF 15 TO 25 MPH
WILL BE COMMON WITH SOME GUSTS AROUND 30-40 MPH. WESTERLY UPSLOPE
SNOW SHOWERS OVER THE SRN GREENS AND WRN DACKS WILL END DURING THE
AFTERNOON WITH ADDITIONAL LIGHT ACCUMULATIONS. IN THE COLD
ADVECTION REGIME...H850 TEMPS FALL TO -17C TO -22C. MAX TEMPS WILL
CONTINUE TO RUN BELOW NORMAL WITH TEENS TO M20S OVER THE HILLS AND
MTNS...AND L20S TO L30S IN THE VALLEY AREAS. TEMPS MAY FALL DURING
THE AFTERNOON. DIMINISHING WINDS AND FRIGID CONDITIONS ARE
ANTICIPATED MON NIGHT WITH HIGH PRESSURE BUILDING IN WITH LOWS
BELOW ZERO OVER THE ADIRONDACK PARK...AND SRN GREENS...SINGLE
DIGITS EVERYWHERE ELSE...EXCEPT 10-15F IN THE MID HUDSON VALLEY
AND SRN LITCHFIELD COUNTY.
&&
.LONG TERM /TUESDAY THROUGH FRIDAY/...
MODEL GUIDANCE IS IN FAIRLY GOOD AGREEMENT KEEPING THE REGION UNDER
A LONGWAVE TROUGH. A SHORT WAVE IS FORECAST TO MOVE THROUGH THE BASE
OF THE TROUGH TUESDAY NIGHT INTO WEDNESDAY BRINGING THE THREAT FOR
SOME SNOW SHOWERS. THE FLOW ALOFT IS EXPECTED TO BECOME MORE ZONAL
WITH RIDGING BUILDING IN AT THE SURFACE AND IN THE LOW LEVELS OF THE
ATMOSPHERE FOR THURSDAY BETWEEN SHORT WAVES AS THE UPPER LOW OVER
EASTERN CANADA/HUDSONS BAY SHIFTS A BIT NORTHWARD. THE SURFACE HIGH
WILL WEAKEN AND SHIFT EASTWARD AS ANOTHER SHORT WAVE TROUGH
APPROACHES FROM THE GREAT LAKES THURSDAY NIGHT. THE UPPER TROUGH AND
ASSOCIATED SURFACE LOW PRESSURE SHOULD CROSS THE REGION FRIDAY
BRINGING WIDESPREAD CHANCES FOR SNOW SHOWERS. QPF SHOULD BE LIGHT
SINCE MOISTURE ASSOCIATED WITH THE FEATURES WILL BE FAIRLY LIMITED.
AS FOR TEMPERATURES LOOKING AT AROUND SEASONABLE LEVELS FOR EARLY
FEBRUARY. SHOULD WARM TO A BIT ABOVE NORMAL ON FRIDAY AHEAD OF THE
APPROACHING LOW PRESSURE SYSTEM.
NORMALS FEB 5TH-8TH:
ALBANY: HIGHS LOWER 30S. LOWS MID TEENS.
GLENS FALLS: HIGHS LOWER 30S. LOWS UPPER SINGLE DIGITS.
POUGHKEEPSIE: HIGHS UPPER 30S. LOWS UPPER TEENS.
BENNINGTON: HIGHS LOWER 30S. LOWS MID TEENS.
PITTSFIELD: HIGHS AROUND 30. LOWS MID TEENS.
&&
.AVIATION /15Z SATURDAY THROUGH WEDNESDAY/...
HIGHER PRESSURE OVER THE REGION THIS MORNING WILL WEAKEN AS A
CLIPPER LOW APPROACHES FROM THE GREAT LAKES. THE CLIPPER LOW IS
EXPECTED TO WEAKEN AS IT MOVES OVER THE REGION TONIGHT. THERE IS A
CHANCE OF SNOW SHOWERS FROM MID/LATE AFTERNOON THROUGH THE EVENING.
MAINLY VFR CONDITIONS ARE EXPECTED WITH MVFR POSSIBLE WITH ANY SNOW
SHOWERS. MVFR SHOULD DEVELOP AFTER MIDNIGHT.
SOUTH TO SOUTHWEST WINDS TODAY AHEAD OF THE APPROACHING CLIPPER LOW
BECOMING LIGHT AND VARIABLE TONIGHT.
OUTLOOK...
SUN...MAINLY VFR. SUB-VFR WITH CHC LIGHT SNOW MID TO LATE AFTN.
SUN NIGHT...MAINLY VFR. SUB-VFR WITH A LIGHT SNOW. AT KPSF SNOW
LIKELY AFTER MIDNIGHT.
MON-TUE...VFR. NO SIG WX.
TUE NIGHT. MAINLY VFR. CHC -SHSN MAINLY AFTER MIDNIGHT.
WED...MAINLY VFR. CHC -SHSN IN THE AM AND SLIGHT CHC IN THE AFTN.
&&
.HYDROLOGY...
THE NEXT 5 DAYS EXTENDING INTO THE MIDDLE OF NEXT WEEK WILL FEATURE
NO HYDRO PROBLEMS. COLD TEMPS AND LIGHT PCPN SYSTEMS /SNOW AS THE
PTYPE/ WILL ALLOW RIVERS AND STREAM TO CONTINUE TO RECEDE FROM
LAST WEEKS STORM SYSTEM.
THE BELOW NORMAL TEMPERATURES WILL ALLOW ICE TO REFORM AND THICKEN
ON BODIES OF WATER IN THE ALBANY HYDRO SERVICE AREA.
FOR SPECIFIC RIVER AND LAKE FORECASTS...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...FRUGIS/WASULA
NEAR TERM...FRUGIS/WASULA
SHORT TERM...WASULA
LONG TERM...IAA
AVIATION...IAA
HYDROLOGY...WASULA
AREA FORECAST DISCUSSION
NWS ALBANY NY
641 AM EST SAT FEB 2 2013
.SYNOPSIS...
HIGH PRESSURE WILL BRIEFLY BUILD IN FROM SOUTHERN QUEBEC
THIS MORNING. A CLIPPER LOW WILL APPROACH FROM THE LOWER GREAT
LAKES REGION WITH ISOLATED TO SCATTERED SNOW SHOWERS LATE THIS
AFTERNOON INTO THIS EVENING. ANOTHER CLIPPER WILL IMPACT THE REGION
LATE SUNDAY INTO SUNDAY NIGHT WITH SOME LIGHT SNOW AND CONTINUED
BELOW NORMAL TEMPERATURES TO OPEN NEXT WEEK.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
AS OF 640 AM EST...THE LAKE EFFECT SNOWS HAVE ENDED SOUTH AND WEST
OF THE CAPITAL REGION WITH JUST SOME ISOLD SNOW SHOWERS AND
FLURRIES AROUND...AS HIGH PRESSURE WILL BRIEFLY BUILD IN FROM SRN
QUEBEC THIS MORNING. A WEAK STATIONARY BOUNDARY OVER UPSTATE NY
AND NEW ENGLAND WILL LIFT BACK NORTHWARD AHEAD OF A WEAK LOW
PRESSURE SYSTEM OVER GEORGIAN BAY. SOME NEW LAKE EFFECT SNOW
SHOWERS HAVE REKINDLED OFF OF LAKE ONTARIO...AND ARE IMPACTING THE
TUG HILL PLATEAU AT 1130 UTC.
THE LOW AND MID LEVEL FLOW WILL CONTINUE TO BACK TO THE W/SW...AND
LAKE EFFECT SNOWFALL WILL BREAK OUT FURTHER OVER EXTREME NRN NY
OFF LAKE ONTARIO. A SW FLOW TRAJECTORY WILL NOT IMPACT THE ALY
FCST AREA MUCH. THE 240 DEGREE TRAJECTORY IS EXPECTED TO IMPACT
LOCATIONS JUST NORTH AND WEST OF THE WRN DACKS. THE LATEST ALY
HIRES WRF COMPOSITE REFLECTIVITY...AND 3-KM HRRR SHOW LITTLE
IMPACT IN OUR AREA TODAY. WE KEPT SOME HIGH CHC AND LIKELY POPS
NORTH OF OLD FORGE IN HERKIMER COUNTY...AND NW HAMILTON COUNTIES.
THERE IS SOME WEAK WARM ADVECTION WITH THE BOUNDARY TOO...SO SOME
SLIGHT AND LOW CHC POPS WERE EXPANDED SOUTH TO THE W-CNTRL MOHAWK
VALLEY.
ANOTHER CLIPPER LOW MOVING ACROSS WI/IL THIS MORNING WILL APPROACH
THE REGION FOR LATE THIS AFTERNOON...AND TONIGHT WITH SOME
SCATTERED SNOW SHOWERS OR LIGHT SNOW. THE SHORT-WAVE TO THIS
CLIPPER IS MOVING INTO THE MIDWEST THIS MORNING VIA THE WATER
VAPOR LOOP. CHC POPS WERE EXPANDED OVER MOST OF THE FCST AREA LATE
THIS AFTERNOON INTO EARLY THIS EVENING.
DESPITE WEAK LOW TO MID LEVEL WARM ADVECTION...H850 TEMPS WILL
STILL BE -12C TO -16C FROM SOUTH TO NORTH OVER THE CWA. EXPECT
HIGHS TO BE 5 TO 10 DEGREES BELOW NORMAL WITH HIGHS IN THE MID TO
U20S IN THE CAPITAL DISTRICT...THE MID HUDSON VALLEY...AND CT
VALLEY. EXPECT TEENS TO L20S OVER THE MTNS...LAKE GEORGE
REGION...W-CNTRL MOHAWK VALLEY...SRN VT...AND THE LITCHFIELD HILLS.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH MONDAY NIGHT/...
TONIGHT...THE FIRST OF TWO CLIPPERS PASSES SOUTH OF THE REGION
WITH SCT SNOW SHOWERS/LIGHT SNOW ENDING FROM NORTH TO SOUTH.
EXPECT MAINLY COATINGS TO A HALF AN INCH AROUND THE REGION.
PORTIONS OF THE ERN CATSKILLS...AND WRN ADIRONDACKS COULD SEE
AROUND AN INCH OR SO. THE FLOW VEERS TO THE W/NW AGAIN WITH THE
UPPER LEVEL TROUGH OVER CNTRL-ERN CANADA CONTINUING TO THE DRIVE
THE WX OVER NY AND NEW ENGLAND. MIN TEMPS WERE BLENDED FROM THE
MET/MAV GUIDANCE WITH SINGLE DIGITS NORTH OF THE CAPITAL
REGION...AND THE MOHAWK VALLEY...AND TEENS FROM THE I-90 CORRIDOR
SOUTH AND EAST.
SUNDAY-SUNDAY NIGHT...ANOTHER LULL IS BRIEFLY EXPECTED IN THE PARADE
OF SHORT-WAVES/CLIPPERS IN THE W/NW FLOW ALOFT SUNDAY MORNING. THE
GUIDANCE HAS TRENDED A BIT SLOWER WITH THE NEXT CLIPPER. SOME
SLIGHT CHC POPS WERE PUT IN DURING THE LATE MORNING WEST OF THE
HUDSON RIVER VALLEY...AND THEN CHC POPS WERE PUT IN EVERYWHERE IN
THE PM INTO THE EVENING. THIS CLIPPER AND ITS ASSOCIATED SHORT-
WAVE MOVE ACROSS THE CNTRL-ERN GREAT LAKES INTO THE REGION. THEIR
IS SOME PRONOUNCED CYCLONIC VORTICITY ADVECTION WITH IT. THE
DISTURBANCE WILL PRODUCE A ROUND OF LIGHT SNOW FOR THE REGION WITH
GENERALLY A DUSTING TO AN INCH OR SO IN MOST LOCATIONS. THE SHORT-
WAVE ENERGY WITH THIS CLIPPER WILL LIKELY PHASE WITH A STORM EAST
OF THE GULF OF MAINE SUNDAY NIGHT. THE STORM WILL INTENSIFY AND
DEEPEN NEAR THE CANADIAN MARITIMES. SOME WESTERLY UPSLOPE OR LAKE
EFFECT SNOWFALL MAY IMPACT THE SRN GREENS AND WRN DACKS. WE HAVE
1-4" OF SNOW SUNDAY TO SUNDAY NIGHT IN THESE AREAS. HIGHS WILL
RANGE FROM THE 20S TO L30S ACROSS THE REGION...TO SINGLE DIGITS TO
TEENS FOR LOWS.
MONDAY-MONDAY NIGHT...THE WORK WEEK WILL OPEN WITH BLUSTERY AND COLD
CONDITIONS...AS A DEEPENING AND INTENSIFYING LOW PRESSURE SYSTEM
MOVES TOWARD LABRADOR...AND ARCTIC HIGH PRESSURE BUILDS IN FROM
THE GREAT LAKES REGION AND ONTARIO. W/NW WINDS OF 15 TO 25 MPH
WILL BE COMMON WITH SOME GUSTS AROUND 30-40 MPH. WESTERLY UPSLOPE
SNOW SHOWERS OVER THE SRN GREENS AND WRN DACKS WILL END DURING THE
AFTERNOON WITH ADDITIONAL LIGHT ACCUMULATIONS. IN THE COLD
ADVECTION REGIME...H850 TEMPS FALL TO -17C TO -22C. MAX TEMPS WILL
CONTINUE TO RUN BELOW NORMAL WITH TEENS TO M20S OVER THE HILLS AND
MTNS...AND L20S TO L30S IN THE VALLEY AREAS. TEMPS MAY FALL DURING
THE AFTERNOON. DIMINISHING WINDS AND FRIGID CONDITIONS ARE
ANTICIPATED MON NIGHT WITH HIGH PRESSURE BUILDING IN WITH LOWS
BELOW ZERO OVER THE ADIRONDACK PARK...AND SRN GREENS...SINGLE
DIGITS EVERYWHERE ELSE...EXCEPT 10-15F IN THE MID HUDSON VALLEY
AND SRN LITCHFIELD COUNTY.
&&
.LONG TERM /TUESDAY THROUGH FRIDAY/...
MODEL GUIDANCE IS IN FAIRLY GOOD AGREEMENT KEEPING THE REGION UNDER
A LONGWAVE TROUGH. A SHORT WAVE IS FORECAST TO MOVE THROUGH THE BASE
OF THE TROUGH TUESDAY NIGHT INTO WEDNESDAY BRINGING THE THREAT FOR
SOME SNOW SHOWERS. THE FLOW ALOFT IS EXPECTED TO BECOME MORE ZONAL
WITH RIDGING BUILDING IN AT THE SURFACE AND IN THE LOW LEVELS OF THE
ATMOSPHERE FOR THURSDAY BETWEEN SHORT WAVES AS THE UPPER LOW OVER
EASTERN CANADA/HUDSONS BAY SHIFTS A BIT NORTHWARD. THE SURFACE HIGH
WILL WEAKEN AND SHIFT EASTWARD AS ANOTHER SHORT WAVE TROUGH
APPROACHES FROM THE GREAT LAKES THURSDAY NIGHT. THE UPPER TROUGH AND
ASSOCIATED SURFACE LOW PRESSURE SHOULD CROSS THE REGION FRIDAY
BRINGING WIDESPREAD CHANCES FOR SNOW SHOWERS. QPF SHOULD BE LIGHT
SINCE MOISTURE ASSOCIATED WITH THE FEATURES WILL BE FAIRLY LIMITED.
AS FOR TEMPERATURES LOOKING AT AROUND SEASONABLE LEVELS FOR EARLY
FEBRUARY. SHOULD WARM TO A BIT ABOVE NORMAL ON FRIDAY AHEAD OF THE
APPROACHING LOW PRESSURE SYSTEM.
NORMALS FEB 5TH-8TH:
ALBANY: HIGHS LOWER 30S. LOWS MID TEENS.
GLENS FALLS: HIGHS LOWER 30S. LOWS UPPER SINGLE DIGITS.
POUGHKEEPSIE: HIGHS UPPER 30S. LOWS UPPER TEENS.
BENNINGTON: HIGHS LOWER 30S. LOWS MID TEENS.
PITTSFIELD: HIGHS AROUND 30. LOWS MID TEENS.
&&
.AVIATION /12Z SATURDAY THROUGH WEDNESDAY/...
HIGHER PRESSURE OVER THE REGION THIS MORNING WILL WEAKEN AS A
CLIPPER LOW APPROACHES FROM THE GREAT LAKES. THE CLIPPER LOW IS
EXPECTED TO WEAKEN AS IT MOVES OVER THE REGION TONIGHT. THERE IS A
CHANCE OF SNOW SHOWERS FROM MID/LATE AFTERNOON THROUGH THE EVENING.
MAINLY VFR CONDITIONS ARE EXPECTED WITH MVFR POSSIBLE WITH ANY SNOW
SHOWERS. MVFR SHOULD DEVELOP AFTER MIDNIGHT.
SOUTH TO SOUTHWEST WINDS TODAY AHEAD OF THE APPROACHING CLIPPER LOW
BECOMING LIGHT AND VARIABLE TONIGHT.
OUTLOOK...
SUN...MAINLY VFR. SUB-VFR WITH CHC LIGHT SNOW MID TO LATE AFTN.
SUN NIGHT...MAINLY VFR. SUB-VFR WITH A LIGHT SNOW. AT KPSF SNOW
LIKELY AFTER MIDNIGHT.
MON-TUE...VFR. NO SIG WX.
TUE NIGHT. MAINLY VFR. CHC -SHSN MAINLY AFTER MIDNIGHT.
WED...MAINLY VFR. CHC -SHSN IN THE AM AND SLIGHT CHC IN THE AFTN.
&&
.HYDROLOGY...
THE NEXT 5 DAYS EXTENDING INTO THE MIDDLE OF NEXT WEEK WILL FEATURE
NO HYDRO PROBLEMS. COLD TEMPS AND LIGHT PCPN SYSTEMS /SNOW AS THE
PTYPE/ WILL ALLOW RIVERS AND STREAM TO CONTINUE TO RECEDE FROM
LAST WEEKS STORM SYSTEM.
THE BELOW NORMAL TEMPERATURES WILL ALLOW ICE TO REFORM AND THICKEN
ON BODIES OF WATER IN THE ALBANY HYDRO SERVICE AREA.
FOR SPECIFIC RIVER AND LAKE FORECASTS...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...WASULA
NEAR TERM...WASULA
SHORT TERM...WASULA
LONG TERM...IAA
AVIATION...IAA
HYDROLOGY...WASULA
AREA FORECAST DISCUSSION
NWS ALBANY NY
416 AM EST SAT FEB 2 2013
.SYNOPSIS...
HIGH PRESSURE WILL BRIEFLY BUILD IN FROM SOUTHERN QUEBEC
THIS MORNING. A CLIPPER LOW WILL APPROACH FROM THE LOWER GREAT
LAKES REGION WITH ISOLATED TO SCATTERED SNOW SHOWERS LATE THIS
AFTERNOON INTO THIS EVENING. ANOTHER CLIPPER WILL IMPACT THE REGION
LATE SUNDAY INTO SUNDAY NIGHT WITH SOME LIGHT SNOW AND CONTINUED
BELOW NORMAL TEMPERATURES TO OPEN NEXT WEEK.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
AS OF 345 AM EST...THE LAKE EFFECT SNOWS HAVE ENDED SOUTH AND WEST
OF THE CAPITAL REGION...AS HIGH PRESSURE WILL BRIEFLY BUILD IN
FROM SRN QUEBEC THIS MORNING. A WEAK STATIONARY BOUNDARY OVER
UPSTATE NY AND NEW ENGLAND WILL LIFT BACK NORTHWARD AHEAD OF A
WEAK LOW PRESSURE SYSTEM OVER GEORGIAN BAY.
THE LOW AND MID LEVEL FLOW WILL BACK TO THE W/SW...AND LAKE EFFECT
SNOWFALL WILL BREAK OUT OVER EXTREME NRN NY OFF LAKE ONTARIO. A SW
FLOW TRAJECTORY WILL NOT IMPACT THE ALY FCST AREA MUCH. THE 240
DEGREE TRAJECTORY IS EXPECTED TO IMPACT LOCATIONS JUST NORTH AND
WEST OF THE WRN DACKS. THE LATEST ALY HIRES WRF COMPOSITE
REFLECTIVITY...AND 3-KM HRRR SHOW LITTLE IMPACT IN OUR AREA
TODAY. WE KEPT SOME HIGH CHC AND LIKELY POPS NORTH OF OLD FORGE IN
HERKIMER COUNTY...AND NW HAMILTON COUNTIES. THERE IS SOME WEAK
WARM ADVECTION WITH THE BOUNDARY TOO...SO SOME SLIGHT AND LOW CHC
POPS WERE EXPANDED SOUTH TO THE W-CNTRL MOHAWK VALLEY.
ANOTHER CLIPPER LOW MOVING ACROSS WI/IL THIS MORNING WILL APPROACH
THE REGION FOR LATE THIS AFTERNOON...AND TONIGHT WITH SOME
SCATTERED SNOW SHOWERS OR LIGHT SNOW. THE SHORT-WAVE TO THIS
CLIPPER IS MOVING INTO THE MIDWEST THIS MORNING VIA THE WATER
VAPOR LOOP. CHC POPS WERE EXPANDED OVER MOST OF THE FCST AREA LATE
THIS AFTERNOON INTO EARLY THIS EVENING.
DESPITE WEAK LOW TO MID LEVEL WARM ADVECTION...H850 TEMPS WILL
STILL BE -12C TO -16C FROM SOUTH TO NORTH OVER THE CWA. EXPECT
HIGHS TO BE 5 TO 10 DEGREES BELOW NORMAL WITH HIGHS IN THE MID TO
U20S IN THE CAPITAL DISTRICT...THE MID HUDSON VALLEY...AND CT
VALLEY. EXPECT TEENS TO L20S OVER THE MTNS...LAKE GEORGE
REGION...W-CNTRL MOHAWK VALLEY...SRN VT...AND THE LITCHFIELD HILLS.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH MONDAY NIGHT/...
TONIGHT...THE FIRST OF TWO CLIPPERS PASSES SOUTH OF THE REGION
WITH SCT SNOW SHOWERS/LIGHT SNOW ENDING FROM NORTH TO SOUTH.
EXPECT MAINLY COATINGS TO A HALF AN INCH AROUND THE REGION.
PORTIONS OF THE ERN CATSKILLS...AND WRN ADIRONDACKS COULD SEE
AROUND AN INCH OR SO. THE FLOW VEERS TO THE W/NW AGAIN WITH THE
UPPER LEVEL TROUGH OVER CNTRL-ERN CANADA CONTINUING TO THE DRIVE
THE WX OVER NY AND NEW ENGLAND. MIN TEMPS WERE BLENDED FROM THE
MET/MAV GUIDANCE WITH SINGLE DIGITS NORTH OF THE CAPITAL
REGION...AND THE MOHAWK VALLEY...AND TEENS FROM THE I-90 CORRIDOR
SOUTH AND EAST.
SUNDAY-SUNDAY NIGHT...ANOTHER LULL IS BRIEFLY EXPECTED IN THE PARADE
OF SHORT-WAVES/CLIPPERS IN THE W/NW FLOW ALOFT SUNDAY MORNING. THE
GUIDANCE HAS TRENDED A BIT SLOWER WITH THE NEXT CLIPPER. SOME
SLIGHT CHC POPS WERE PUT IN DURING THE LATE MORNING WEST OF THE
HUDSON RIVER VALLEY...AND THEN CHC POPS WERE PUT IN EVERYWHERE IN
THE PM INTO THE EVENING. THIS CLIPPER AND ITS ASSOCIATED SHORT-
WAVE MOVE ACROSS THE CNTRL-ERN GREAT LAKES INTO THE REGION. THEIR
IS SOME PRONOUNCED CYCLONIC VORTICITY ADVECTION WITH IT. THE
DISTURBANCE WILL PRODUCE A ROUND OF LIGHT SNOW FOR THE REGION WITH
GENERALLY A DUSTING TO AN INCH OR SO IN MOST LOCATIONS. THE SHORT-
WAVE ENERGY WITH THIS CLIPPER WILL LIKELY PHASE WITH A STORM EAST
OF THE GULF OF MAINE SUNDAY NIGHT. THE STORM WILL INTENSIFY AND
DEEPEN NEAR THE CANADIAN MARITIMES. SOME WESTERLY UPSLOPE OR LAKE
EFFECT SNOWFALL MAY IMPACT THE SRN GREENS AND WRN DACKS. WE HAVE
1-4" OF SNOW SUNDAY TO SUNDAY NIGHT IN THESE AREAS. HIGHS WILL
RANGE FROM THE 20S TO L30S ACROSS THE REGION...TO SINGLE DIGITS TO
TEENS FOR LOWS.
MONDAY-MONDAY NIGHT...THE WORK WEEK WILL OPEN WITH BLUSTERY AND COLD
CONDITIONS...AS A DEEPENING AND INTENSIFYING LOW PRESSURE SYSTEM
MOVES TOWARD LABRADOR...AND ARCTIC HIGH PRESSURE BUILDS IN FROM
THE GREAT LAKES REGION AND ONTARIO. W/NW WINDS OF 15 TO 25 MPH
WILL BE COMMON WITH SOME GUSTS AROUND 30-40 MPH. WESTERLY UPSLOPE
SNOW SHOWERS OVER THE SRN GREENS AND WRN DACKS WILL END DURING THE
AFTERNOON WITH ADDITIONAL LIGHT ACCUMULATIONS. IN THE COLD
ADVECTION REGIME...H850 TEMPS FALL TO -17C TO -22C. MAX TEMPS WILL
CONTINUE TO RUN BELOW NORMAL WITH TEENS TO M20S OVER THE HILLS AND
MTNS...AND L20S TO L30S IN THE VALLEY AREAS. TEMPS MAY FALL DURING
THE AFTERNOON. DIMINISHING WINDS AND FRIGID CONDITIONS ARE
ANTICIPATED MON NIGHT WITH HIGH PRESSURE BUILDING IN WITH LOWS
BELOW ZERO OVER THE ADIRONDACK PARK...AND SRN GREENS...SINGLE
DIGITS EVERYWHERE ELSE...EXCEPT 10-15F IN THE MID HUDSON VALLEY
AND SRN LITCHFIELD COUNTY.
&&
.LONG TERM /TUESDAY THROUGH FRIDAY/...
MODEL GUIDANCE IS IN FAIRLY GOOD AGREEMENT KEEPING THE REGION UNDER
A LONGWAVE TROUGH. A SHORT WAVE IS FORECAST TO MOVE THROUGH THE BASE
OF THE TROUGH TUESDAY NIGHT INTO WEDNESDAY BRINGING THE THREAT FOR
SOME SNOW SHOWERS. THE FLOW ALOFT IS EXPECTED TO BECOME MORE ZONAL
WITH RIDGING BUILDING IN AT THE SURFACE AND IN THE LOW LEVELS OF THE
ATMOSPHERE FOR THURSDAY BETWEEN SHORT WAVES AS THE UPPER LOW OVER
EASTERN CANADA/HUDSONS BAY SHIFTS A BIT NORTHWARD. THE SURFACE HIGH
WILL WEAKEN AND SHIFT EASTWARD AS ANOTHER SHORT WAVE TROUGH
APPROACHES FROM THE GREAT LAKES THURSDAY NIGHT. THE UPPER TROUGH AND
ASSOCIATED SURFACE LOW PRESSURE SHOULD CROSS THE REGION FRIDAY
BRINGING WIDESPREAD CHANCES FOR SNOW SHOWERS. QPF SHOULD BE LIGHT
SINCE MOISTURE ASSOCIATED WITH THE FEATURES WILL BE FAIRLY LIMITED.
AS FOR TEMPERATURES LOOKING AT AROUND SEASONABLE LEVELS FOR EARLY
FEBRUARY. SHOULD WARM TO A BIT ABOVE NORMAL ON FRIDAY AHEAD OF THE
APPROACHING LOW PRESSURE SYSTEM.
NORMALS FEB 5TH-8TH:
ALBANY: HIGHS LOWER 30S. LOWS MID TEENS.
GLENS FALLS: HIGHS LOWER 30S. LOWS UPPER SINGLE DIGITS.
POUGHKEEPSIE: HIGHS UPPER 30S. LOWS UPPER TEENS.
BENNINGTON: HIGHS LOWER 30S. LOWS MID TEENS.
PITTSFIELD: HIGHS AROUND 30. LOWS MID TEENS.
&&
.AVIATION /09Z SATURDAY THROUGH WEDNESDAY/...
HIGHER PRESSURE BRIEFLY BUILDS INTO THE REGION FROM THE SOUTHWEST
THIS MORNING AND THE LAKE EFFECT SNOW WILL DISSIPATE. A CLIPPER LOW
WILL APPROACH FROM THE GREAT LAKES REGION TODAY AND IS EXPECTED TO
WEAKEN AS IT MOVES OVER THE REGION TONIGHT.
EXPECTING VFR CONDITIONS...THE EXCEPTION WILL BE MVFR CONDITIONS AT
KPSF FOR A COUPLE HOURS AT THE BEGINNING OF THE TAF TIME AND
POSSIBLY AGAIN LATE IN THE EVENING.
GUSTY WEST TO NORTHWEST WINDS AT KALB AND KPSF WILL WEAKEN EARLY
THIS MORNING. THE FLOW WILL SHIFT TO SOUTHWEST TO SOUTH DURING THE
DAY AHEAD OF THE APPROACHING CLIPPER LOW.
OUTLOOK...
SUN...MAINLY VFR. SUB-VFR WITH CHC LIGHT SNOW MID TO LATE AFTN.
SUN NIGHT...MAINLY VFR. SUB-VFR WITH A LIGHT SNOW. AT KPSF SNOW
LIKELY AFTER MIDNIGHT.
MON-TUE...VFR. NO SIG WX.
TUE NIGHT. MAINLY VFR. CHC -SHSN MAINLY AFTER MIDNIGHT.
WED...MAINLY VFR. CHC -SHSN IN THE AM AND SLIGHT CHC IN THE AFTN.
&&
.HYDROLOGY...
THE NEXT 5 DAYS EXTENDING INTO THE MIDDLE OF NEXT WEEK WILL FEATURE
NO HYDRO PROBLEMS. COLD TEMPS AND LIGHT PCPN SYSTEMS /SNOW AS THE
PTYPE/ WILL ALLOW RIVERS AND STREAM TO CONTINUE TO RECEDE FROM
LAST WEEKS STORM SYSTEM.
THE BELOW NORMAL TEMPERATURES WILL ALLOW ICE TO REFORM AND THICKEN
ON BODIES OF WATER IN THE ALBANY HYDRO SERVICE AREA.
FOR SPECIFIC RIVER AND LAKE FORECASTS...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...WASULA
NEAR TERM...WASULA
SHORT TERM...WASULA
LONG TERM...IAA
AVIATION...IAA
HYDROLOGY...WASULA
AREA FORECAST DISCUSSION
NWS ALBANY NY
111 AM EST SAT FEB 2 2013
.SYNOPSIS...
AS A COLD CANADIAN AIR MASS CONTINUES TO MOVE INTO THE
REGION TODAY...IT WILL BE COLD AND WINDY. SOME LAKE EFFECT SNOW WILL
AFFECT PORTIONS OF THE MOHAWK AND SCHOHARIE VALLEYS AND CAPITAL
REGION THIS MORNING. THE WIND AND SNOW SHOWERS WILL DIMINISH
TONIGHT. IT WILL REMAIN COLD THROUGH THE WEEKEND AND THERE IS A
CHANCE FOR SOME LIGHT SNOW...ESPECIALLY ON SUNDAY.
&&
.NEAR TERM /UNTIL 6 AM THIS MORNING/...
AS OF 1245 AM EST...THE LATEST RUC40 SHOWS A H500 VORT MAX MOVING
ACROSS THE REGION. THE LAKE EFFECT BAND AND SNOW SHOWERS HAVE
DECREASED DRAMATICALLY OVER THE PAST FEW HOURS. A NARROW FILAMENT
CONTINUES OVER THE NRN CATSKILLS IN SCHOHARIE COUNTY...AND THE
HELDERBERGS IN WRN ALBANY COUNTY. A QUICK COATING TO UP TO AN INCH
IS POSSIBLE BEFORE THE BAND FALLS APART WITH THE FLOW CONTINUING
TO VEER TO THE NORTHWEST. THE LATEST HRRR SHOWS THE DISSIPATION OF
THE BAND BTWN 06Z-08Z. THE FLOW WILL BEGIN TO BACK TO THE W/SW TOWARDS
SUNRISE...AS THE NEXT CLIPPER APPROACHES. SOME ISOLD-SCT FLURRIES
AND SNOW SHOWERS MAY IMPACT THE WRN DACKS/WRN MOHAWK VALLEY. THE TEMPS
LOOK ON TRACK...WITH SLIGHT DEVIATIONS UPWARD BASED ON THE
LINGERING CLOUDS.
OVERNIGHT LOWS WILL BE 10-15 DEGREES ALBANY SOUTHWARD..BUT 0-10 TO
THE NORTH AND WEST OF TOWN. SOME OF THE COLDEST SPOTS IN THE
ADIRONDACKS WILL DIP A LITTLE BELOW ZERO. WINDS CHILLS WILL MAKE IT
FEEL A BIT COLDER THAN AT TIMES...BUT NOT LOW ENOUGH TO ISSUE
ADVISORIES.
&&
.SHORT TERM /6 AM THIS MORNING THROUGH SUNDAY NIGHT/...
A WEAK SHORTWAVE WILL PASS TO THE NORTH OF THE REGION ON SATURDAY
INTO SATURDAY NIGHT. THIS MAY ALLOW FOR SOME LIGHT SNOW SHOWERS
ACROSS THE ADIRONDACKS. BY LATE IN THE DAY A WAVE MOVING FROM THE
THE OHIO VALLEY TO THE MID ATLANTIC STATES MAY BRING A CHANCE FOR
LIGHT SNOW TO THE SOUTHERN PART OF THE FORECAST AREA...GENERALLY
SOUTH OF ALBANY. AS THE WAVE MOVES OFFSHORE SATURDAY NIGHT AND
SUNDAY...IT WILL INDUCE SURFACE LOW DEVELOPMENT...SO THERE WILL BE
A BETTER CHANCE FOR SOME LIGHT SNOW ACROSS THE REGION LATE SATURDAY
NIGHT INTO SUNDAY...ESPECIALLY SOUTH OF ALBANY.
IT WILL REMAIN COLD. HIGHS SATURDAY WILL BE IN THE MID TEENS TO THE
20S. LOWS SATURDAY NIGHT GENERALLY IN THE SINGLE NUMBERS AND
TEENS...AND HIGHS SUNDAY IN THE 20S TO LOWER 30S.
&&
.LONG TERM /MONDAY THROUGH FRIDAY/...
THE MODELS ARE IN PRETTY GOOD AGREEMENT FOR THE EXTENDED PERIOD. A
LARGE BROAD TROUGH WILL CONTINUE MUCH OF THE PERIOD.
A SERIES OF CLIPPERS WILL CONTINUE TO PARADE THROUGH THE TROUGH
BRINGING THE THREAT OF NUISANCE SNOW SHOWERS...AND PERHAPS MORE
SIGNIFICANT LAKE EFFECT SNOWS. TEMPERATURES WILL CONTINUE TO TREND
BELOW NORMAL.
MONDAY ONE LOW PRESSURE WILL BE DEPARTING WELL TO OUR
EAST...BRINGING ANOTHER SURGE OF MODIFIED ARCTIC AIR ALONG WITH THE
USUAL THREAT OF SNOW SHOWERS OFF LAKE ONTARIO THAT WILL PROBABLY AT
LEAST BRUSHING OUR NORTHWESTERN ZONES AND SOME UPSLOPE SNOW POSSIBLE
ACROSS THE SOUTHERN GREENS. THE REMAINDER OF THE REGION WILL SEE
MAINLY FLURRIES (SLIGHT CHANCE OF SNOW SHOWERS) OR REMAIN DRY WITH
PARTIAL SUNSHINE. HOWEVER IT WILL BE A BRISK DAY ADDING TO THE CHILL.
HIGH PRESSURE LOOKS TO BUILD IN BY TUESDAY...FOLLOWED BY ANOTHER
CLIPPER ON TUESDAY NIGHT INTO WEDNESDAY. THIS STORM LOOKS TO TRACK
SOUTH OF OUR REGION...MAYBE TOO FAR SOUTH TO GET INTO THE BEST SNOW
SHIELD. FOR NOW...WENT WITH 30 POPS TUESDAY NIGHT LOWERING THEM TO
SLIGHT CHANCES ON WEDNESDAY.
ANOTHER HIGH PRESSURE WILL BUILD IN WEDNESDAY NIGHT THROUGH
THURSDAY. THEN ANOTHER CLIPPER TYPE SYSTEM APPROACHES THURSDAY NIGHT
INTO FRIDAY. THE EUROPEAN MODEL SUGGESTED THIS ONE COULD BE A BIT
STRONGER...AND OFFER MORE IN THE WAY OF QPF. IT WOULD BE COLD FOR
ALL SNOW FROM ALBANY NORTH. FURTHER SOUTH...IT MIGHT BE WARM UP
RIGHT NEAR THE SURFACE TO MIX WITH SOME RAIN.
THE 12Z GFS WAS NOT A ROBUST WITH THE STORM...FURTHER NORTH AND
LIGHTER QPF. FOR NOW...WENT WITH A 40 POP BUT DECIDED TO CALL IT
SNOW (AS OPPOSED TO SNOW SHOWERS).
TEMPERATURES GENERALLY LOOK TO STARTED OUT QUITE COLD ON MONDAY AND
TUESDAY...LOWER TO MID 20S FOR HIGHS CAPITAL DISTRICT AND POINTS
SOUTH...TEENS NORTH...WEST AND EVEN EAST OF THE CAPITAL DISTRICT.
HIGHS WILL MODERATE A LITTLE AFTER THAT. BY FRIDAY...HIGHS WILL
REACH THE 30S ALBANY SOUTHWARD...25-30 REMAINDER OF THE REGION.
OVERNIGHT LOWS WILL BE TEENS FROM SOUTH...SINGLE NUMBERS
NORTH...WITH SELECT SPOTS ESPECIALLY IN THE ADIRONDACKS FROM ZERO TO
10 BELOW.
&&
.AVIATION /06Z SATURDAY THROUGH WEDNESDAY/...
HIGHER PRESSURE BRIEFLY BUILDS INTO THE REGION FROM THE SOUTHWEST
THIS MORNING AND THE LAKE EFFECT SNOW WILL DISSIPATE. A CLIPPER LOW
WILL APPROACH FROM THE GREAT LAKES REGION TODAY AND IS EXPECTED TO
WEAKEN AS IT MOVES OVER THE REGION TONIGHT.
EXPECTING VFR CONDITIONS...THE EXCEPTION WILL BE MVFR CONDITIONS AT
KPSF FOR A COUPLE HOURS AT THE BEGINNING OF THE TAF TIME AND
POSSIBLY AGAIN LATE IN THE EVENING.
GUSTY WEST TO NORTHWEST WINDS AT KALB AND KPSF WILL WEAKEN EARLY
THIS MORNING. THE FLOW WILL SHIFT TO SOUTHWEST TO SOUTH DURING THE
DAY AHEAD OF THE APPROACHING CLIPPER LOW.
OUTLOOK...
SUN...MAINLY VFR. SUB-VFR WITH CHC SNOW DURING THE AFTN AND EVNG.
MON...MAINLY VFR. SLIGHT CHC -SHSN.
TUE...VFR. NO SIG WX.
TUE NIGHT. MAINLY VFR. CHC -SHSN.
WED...MAINLY VFR. SLIGHT CHC -SHSN.
&&
.HYDROLOGY...
NO HYDRO PROBLEMS ARE EXPECTED DURING THE NEXT FIVE DAYS.
TEMPERATURES WILL BE WELL BELOW FREEZING MOST OF THE TIME DURING THE
NEXT FIVE DAYS AND ONLY SNOWFALL IS EXPECTED IN TERMS OF ANY
PRECIPITATION. WITH THE COLD TEMPERATURES RUNOFF HAS DECREASED
SIGNIFICANTLY AND AREA STREAMS AND RIVERS ARE SLOWLY RECEDING.
FOR SPECIFIC RIVER AND LAKE FORECASTS...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...HWJIV/BGM/WASULA
SHORT TERM...HWJIV/BGM
LONG TERM...HWJIV
AVIATION...IAA
HYDROLOGY...BGM
AREA FORECAST DISCUSSION
NWS ALBANY NY
1253 AM EST SAT FEB 2 2013
.SYNOPSIS...
AS A COLD CANADIAN AIR MASS CONTINUES TO MOVE INTO THE
REGION TODAY...IT WILL BE COLD AND WINDY. SOME LAKE EFFECT SNOW WILL
AFFECT PORTIONS OF THE MOHAWK AND SCHOHARIE VALLEYS AND CAPITAL
REGION THIS MORNING. THE WIND AND SNOW SHOWERS WILL DIMINISH
TONIGHT. IT WILL REMAIN COLD THROUGH THE WEEKEND AND THERE IS A
CHANCE FOR SOME LIGHT SNOW...ESPECIALLY ON SUNDAY.
&&
.NEAR TERM /UNTIL 6 AM THIS MORNING/...
AS OF 1245 AM EST...THE LATEST RUC40 SHOWS A H500 VORT MAX MOVING
ACROSS THE REGION. THE LAKE EFFECT BAND AND SNOW SHOWERS HAVE
DECREASED DRAMATICALLY OVER THE PAST FEW HOURS. A NARROW FILAMENT
CONTINUES OVER THE NRN CATSKILLS IN SCHOHARIE COUNTY...AND THE
HELDERBERGS IN WRN ALBANY COUNTY. A QUICK COATING TO UP TO AN INCH
IS POSSIBLE BEFORE THE BAND FALLS APART WITH THE FLOW CONTINUING
TO VEER TO THE NORTHWEST. THE LATEST HRRR SHOWS THE DISSIPATION OF
THE BAND BTWN 06Z-08Z. THE FLOW WILL BEGIN TO BACK TO THE W/SW TOWARDS
SUNRISE...AS THE NEXT CLIPPER APPROACHES. SOME ISOLD-SCT FLURRIES
AND SNOW SHOWERS MAY IMPACT THE WRN DACKS/WRN MOHAWK VALLEY. THE TEMPS
LOOK ON TRACK...WITH SLIGHT DEVIATIONS UPWARD BASED ON THE
LINGERING CLOUDS.
OVERNIGHT LOWS WILL BE 10-15 DEGREES ALBANY SOUTHWARD..BUT 0-10 TO
THE NORTH AND WEST OF TOWN. SOME OF THE COLDEST SPOTS IN THE
ADIRONDACKS WILL DIP A LITTLE BELOW ZERO. WINDS CHILLS WILL MAKE IT
FEEL A BIT COLDER THAN AT TIMES...BUT NOT LOW ENOUGH TO ISSUE
ADVISORIES.
&&
.SHORT TERM /6 AM THIS MORNING THROUGH SUNDAY NIGHT/...
A WEAK SHORTWAVE WILL PASS TO THE NORTH OF THE REGION ON SATURDAY
INTO SATURDAY NIGHT. THIS MAY ALLOW FOR SOME LIGHT SNOW SHOWERS
ACROSS THE ADIRONDACKS. BY LATE IN THE DAY A WAVE MOVING FROM THE
THE OHIO VALLEY TO THE MID ATLANTIC STATES MAY BRING A CHANCE FOR
LIGHT SNOW TO THE SOUTHERN PART OF THE FORECAST AREA...GENERALLY
SOUTH OF ALBANY. AS THE WAVE MOVES OFFSHORE SATURDAY NIGHT AND
SUNDAY...IT WILL INDUCE SURFACE LOW DEVELOPMENT...SO THERE WILL BE
A BETTER CHANCE FOR SOME LIGHT SNOW ACROSS THE REGION LATE SATURDAY
NIGHT INTO SUNDAY...ESPECIALLY SOUTH OF ALBANY.
IT WILL REMAIN COLD. HIGHS SATURDAY WILL BE IN THE MID TEENS TO THE
20S. LOWS SATURDAY NIGHT GENERALLY IN THE SINGLE NUMBERS AND
TEENS...AND HIGHS SUNDAY IN THE 20S TO LOWER 30S.
&&
.LONG TERM /MONDAY THROUGH FRIDAY/...
THE MODELS ARE IN PRETTY GOOD AGREEMENT FOR THE EXTENDED PERIOD. A
LARGE BROAD TROUGH WILL CONTINUE MUCH OF THE PERIOD.
A SERIES OF CLIPPERS WILL CONTINUE TO PARADE THROUGH THE TROUGH
BRINGING THE THREAT OF NUISANCE SNOW SHOWERS...AND PERHAPS MORE
SIGNIFICANT LAKE EFFECT SNOWS. TEMPERATURES WILL CONTINUE TO TREND
BELOW NORMAL.
MONDAY ONE LOW PRESSURE WILL BE DEPARTING WELL TO OUR
EAST...BRINGING ANOTHER SURGE OF MODIFIED ARCTIC AIR ALONG WITH THE
USUAL THREAT OF SNOW SHOWERS OFF LAKE ONTARIO THAT WILL PROBABLY AT
LEAST BRUSHING OUR NORTHWESTERN ZONES AND SOME UPSLOPE SNOW POSSIBLE
ACROSS THE SOUTHERN GREENS. THE REMAINDER OF THE REGION WILL SEE
MAINLY FLURRIES (SLIGHT CHANCE OF SNOW SHOWERS) OR REMAIN DRY WITH
PARTIAL SUNSHINE. HOWEVER IT WILL BE A BRISK DAY ADDING TO THE CHILL.
HIGH PRESSURE LOOKS TO BUILD IN BY TUESDAY...FOLLOWED BY ANOTHER
CLIPPER ON TUESDAY NIGHT INTO WEDNESDAY. THIS STORM LOOKS TO TRACK
SOUTH OF OUR REGION...MAYBE TOO FAR SOUTH TO GET INTO THE BEST SNOW
SHIELD. FOR NOW...WENT WITH 30 POPS TUESDAY NIGHT LOWERING THEM TO
SLIGHT CHANCES ON WEDNESDAY.
ANOTHER HIGH PRESSURE WILL BUILD IN WEDNESDAY NIGHT THROUGH
THURSDAY. THEN ANOTHER CLIPPER TYPE SYSTEM APPROACHES THURSDAY NIGHT
INTO FRIDAY. THE EUROPEAN MODEL SUGGESTED THIS ONE COULD BE A BIT
STRONGER...AND OFFER MORE IN THE WAY OF QPF. IT WOULD BE COLD FOR
ALL SNOW FROM ALBANY NORTH. FURTHER SOUTH...IT MIGHT BE WARM UP
RIGHT NEAR THE SURFACE TO MIX WITH SOME RAIN.
THE 12Z GFS WAS NOT A ROBUST WITH THE STORM...FURTHER NORTH AND
LIGHTER QPF. FOR NOW...WENT WITH A 40 POP BUT DECIDED TO CALL IT
SNOW (AS OPPOSED TO SNOW SHOWERS).
TEMPERATURES GENERALLY LOOK TO STARTED OUT QUITE COLD ON MONDAY AND
TUESDAY...LOWER TO MID 20S FOR HIGHS CAPITAL DISTRICT AND POINTS
SOUTH...TEENS NORTH...WEST AND EVEN EAST OF THE CAPITAL DISTRICT.
HIGHS WILL MODERATE A LITTLE AFTER THAT. BY FRIDAY...HIGHS WILL
REACH THE 30S ALBANY SOUTHWARD...25-30 REMAINDER OF THE REGION.
OVERNIGHT LOWS WILL BE TEENS FROM SOUTH...SINGLE NUMBERS
NORTH...WITH SELECT SPOTS ESPECIALLY IN THE ADIRONDACKS FROM ZERO TO
10 BELOW.
&&
.AVIATION /06Z SATURDAY THROUGH WEDNESDAY/...
MAINLY VFR CONDITIONS WILL PREVAIL THROUGHOUT SATURDAY.
SNOW SHOWERS HAVE FLARED UP ONCE MORE DOWN THE MOHAWK VALLEY. THREW
IN A FOUR HOUR TEMPO TO INCLUDE AT LEAST A 50 PERCENT CERTAINTY
THAT MVFR SNOW SHOWERS COULD TAKE PLACE UP TO HALF OF THE TIME IN
THAT TIME FRAME. WILL CONTINUE TO MONITOR TRENDS. HAVE CONTINUED THE
TEMPO FOR TEMPO SNOW SHOWERS AT KPSF AS WELL. OTHERWISE VFR
CONDITIONS WILL PREVAIL.
NO SNOW SHOWERS EXPECTED AT THE OTHER SITES. THE SKY WILL REMAIN
PARTLY CLOUDY (PROBABLY FREE OF CIGS). EVEN IF ANY DO BRIEFLY
OCCUR...THEY WOULD BE IN THE MVFR RANGE.
THE GUSTY W TO NW WIND (ESPECIALLY AT KALB) WILL DIMINISH WITH TIME
TO AROUND 5-10KTS. (KEPT TEMPS FOR GUSTY WINDS AROUND 20KTS AT ALL
TAF SITES AWHILE THIS EVENING LONGEST AT KALB AND KPSF).
SATURDAY LOOKS MAINLY DRY TO START...BUT THERE IS A SLIGHT
INCREASING THREAT IN MORE SNOW SHOWER ACTIVITY LATER IN THE DAY AS A
CLIPPER NEARS WITH ITS ASSOCIATED COLD FRONT. THE SOUTH WIND WILL
PICK UP TO NEAR 10KTS MIDDAY (WITH A FEW HIGHER GUSTS POSSIBLE AT
KALB). WE ASSIGNED A VCSH DURING THE AFTERNOON AT ALL TAF SITES TO
INDICATE THE POSSIBILITY OF SNOW SHOWERS AROUND...A FEW WHICH COULD
BRIEFLY DROP CONDITIONS TO MVFR BUT RIGHT CONFIDENCE WAS BELOW 30
PERCENT.
OUTLOOK...
SAT NIGHT..VFR. NO SIG WX.
SUN-SUN NIGHT. MAINLY VFR. CHC SUB-VFR -SHSN.
MON-TUE. VFR. NO SIG WX.
TUE NIGHT-WED. MAINLY VFR. CHC SUB-VFR -SHSN.
&&
.HYDROLOGY...
NO HYDRO PROBLEMS ARE EXPECTED DURING THE NEXT FIVE DAYS.
TEMPERATURES WILL BE WELL BELOW FREEZING MOST OF THE TIME DURING THE
NEXT FIVE DAYS AND ONLY SNOWFALL IS EXPECTED IN TERMS OF ANY
PRECIPITATION. WITH THE COLD TEMPERATURES RUNOFF HAS DECREASED
SIGNIFICANTLY AND AREA STREAMS AND RIVERS ARE SLOWLY RECEDING.
FOR SPECIFIC RIVER AND LAKE FORECASTS...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...HWJIV/BGM/WASULA
SHORT TERM...HWJIV/BGM
LONG TERM...HWJIV
AVIATION...HWJIV
HYDROLOGY...BGM
AREA FORECAST DISCUSSION
NWS NORTHERN INDIANA
556 AM EST SAT FEB 2 2013
.UPDATE...
NOTEABLE 3HR PRES FALL MAX OVR NE IL/NW IN THIS MORNING W/COOLING IR
CLD TOPS NOTED WITHIN BURGEONING RADAR RTNS FM NE IL ACRS SRN LK MI
AND INTO SW MI. WHILE SNOW SHIELD HAS BEEN FAIRLY RAGGED SO FAR XPC
MORE ERSTWHILE DVLPMNT NR TERM IN LINE W/LATEST RUC DATA AND SEEN IN
UPSTREAM RADAR TRENDS. IN FACT NOTED BANDING TAKING PLACE OVR NE
IL/SRN LK MI ATTM W/WIDESPREAD 30DBZ+ RTNS NOTED AND INDICATIVE OF
SNOWFALL RATES NR 1 INCH PER HOUR.
WILL BUMP 12-18Z QPF/SNOW GRIDS SLIGHTLY ESP OVR BERRIEN COUNTY AS
SOME LK ENHANCMENT IS OCCURRING. OTRWS GIST OF PRIOR FCST HOLDS THIS
AFTN.
&&
.SHORT TERM...
TODAY THROUGH SUNDAY NIGHT...THE CHALLENGES THIS PERIOD INCLUDE A
NUMBER OF OPPORTUNITIES FOR SNOW INCLUDING A FAST MOVING CLIPPER
TYPE OF SYSTEM TODAY...LAKE EFFECT SNOW TONIGHT AND SUNDAY...AND A
SECOND FAST MOVING SYSTEM ARRIVING SUNDAY NIGHT OR MONDAY. FOR
THIS PACKAGE...FAVORED THE SRF. THE FIRST SYSTEM...THE LEFT EXIT
REGION OF UPPER JET WAS HELPING TO GENERATE SNOW OVER MUCH OF THE
FORECAST AREA EARLY THIS MORNING IN A VERY COLD AIRMASS LINGERING
OVER THE REGION. MOISTURE WAS LIMITED...BUT ISENTROPIC LIFT AND
SOME UPPER LEVEL JET SUPPORT WAS HELPING TO SUSTAIN THE SNOW. THE
ISENTROPIC LIFT SHOULD BE MOST FAVORABLE BETWEEN 09Z AND 15Z.
THEREFORE...WILL KEEP WIDESPREAD LIGHT SNOW ACCUMULATIONS
TODAY...WITH SNOW TAPERING THIS AFTERNOON. CURRENT THINKING IS
SNOW ACCUMULATIONS SHOULD BE AROUND AN INCH. FOR TONIGHT AND
SUNDAY... POOR LAKE EFFECT SNOW SET UP IN A HIGHLY SHEARED LOW
LEVEL ENVIRONMENT...ALTHOUGH DELTA T VALUES DO SUPPORT LAKE EFFECT
SNOW. LOW LEVEL SUBSIDENCE REALLY INCREASES LATER TODAY AND SHOULD
LIMIT SNOWFALL AND INTENSITY. REDUCED SNOW CHANCES CONSIDERABLY
ALL AREAS TONIGHT GIVEN LACK OF FORCING AND UPPER LEVEL SUPPORT
FOR WIDESPREAD SNOW. FOR THE SECOND CLIPPER SYSTEM...KEPT A CHANCE
FOR SNOW LATE SUNDAY NIGHT...WITH A MUCH BETTER CHANCE FOR SNOW
MONDAY AS ISENTROPIC LIFT INCREASES.
&&
.LONG TERM...
COLD PNA PATTN OF LATE ANCHORED BY DEEP POLAR TROUGH OVR HUDSON BAY
AND LW RIDGE ALG THE W COAST OF NOAM WILL RELAX THIS PD AS POLAR
TROUGH MIGRATES INTO BAFFIN BAY. RESULTING FLW PATTN WILL FLATTEN
OUT TO WRLY ACRS THE CONUS W/SIG WARMUP XPCD LT PD. UNTIL THEN HWVR
HAVE TO CONTEND W/CONTD PARADE OF SW RIPPLES EMBEDDED WITHIN STILL
FAIRLY STEEP NWRLY FLW ALOFT. 3RD SW OF NOTE WILL DIVE DOWN ACRS THE
SRN LAKES ON MON AND CONT TO FVR SRN CONSENSUS OF SOLUTIONS W/TRACK
OF THIS SW CNTRD OVR CNTRL IN. WHILE MSTR RTN AGAIN LIMITED...ROBUST
ISENTROPIC RESPONSE XPCD WITHIN ENTRANCE REGION OF UPR JET
COLLOCATED W/TIGHT BAROCLINIC ZONE. GIVEN PWS ARE A BIT BTR THAN NR
TERM SYS...XPCD SIMILAR EVOLUTION W/GENERAL 1-3 IN SNOWFALL ACRS THE
AREA...HEAVIEST CNTRL/SW. WILL BUMP POP SIGLY GIVEN GOOD INTERMODEL
AGREEMENT.
4TH SYS FOLLOWS QUICKLY LT TUE. HWVR PLACEMENT OF UPR JET AND
SOMEWHAT WEAKER RESPONSE ALOFT W/MORE LIMITED MSTR SUGGESTS MUCH
LIGHTER SNOW.
BEYOND THAT...FLW PATTN BREAKS DOWN W/WRN TROUGHING DVLPG TWD LT PD.
LEAD SYS BREAKING EWD OUT OF EPAC IN THIS TRANSITION WILL CROSS THE
AREA ON THU. EC/GFS SIMILAR IN SCOPE W/NARROW BUT IMPORTANT THETA-E
RIDGING DVLPG INADV AND IMPLY A POTENTIAL MIX FAR S/SW LT THU.
REGARDLESS SOME ENTRAINMENT OF FLEDGELING ERN GOMEX MSTR PLUME PSBL
AND WILL BRIDGE GOING POPS HIGHER.
&&
.AVIATION...
LEFT EXIT REGION OF UPPER JET AXIS HELPING TO GENERATE SNOW
UPSTREAM INTO NRN INDIANA IN VERY COLD AIRMASS LINGERING OVER THE
REGION. MOISTURE SOMEWHAT LIMITED...BUT VERY EFFICIENT SETUP TO
PRODUCE SNOW WITH VISIBILITIES DOWN TO 1 MILE. MADE SOME MAINLY
MINOR UPDATES TO THE ONGOING TAFS WITH THIS NEW ISSUANCE. VSBYS
SHOULD IMPROVE AFTER CLIPPER TYPE SYSTEM MOVES THROUGH...ALTHOUGH
EXPECT CIGS TO REMAIN MVFR.
&&
.IWX WATCHES/WARNINGS/ADVISORIES...
IN...NONE.
MI...NONE.
OH...NONE.
LM...SMALL CRAFT ADVISORY UNTIL 5 AM EST EARLY THIS MORNING FOR
LMZ043-046.
&&
$$
SHORT TERM...SKIPPER
LONG TERM...T
AVIATION...SKIPPER
UPDATE...T
AREA FORECAST DISCUSSION
NWS BALTIMORE MD/WASHINGTON DC
1013 AM EST SAT FEB 2 2013
.SYNOPSIS...
NORTHWEST FLOW WILL KEEP COLD AIR FUNNELING DOWN OVER THE MID
ATLANTIC STATES THROUGH WEDNESDAY. A SERIES OF WEAK LOW PRESSURE
SYSTEMS WILL QUICKLY PASS THROUGH THE REGION THROUGH WEDNESDAY.
&&
.NEAR TERM /UNTIL 7 PM THIS EVENING/...
NEXT CLIPPER SYSTEM ON TRACK TO IMPACT THE REGION WITH LIGHT SNOW
STARTING THIS AFTERNOON AND CONTINUING THROUGH THE EVENING HOURS.
NOT MUCH IN THE WAY OF UPPER LEVEL DYNAMICS WITH THIS SYSTEM...SO
AM NOT EXPECTING ANYTHING OTHER A PERIOD OF LIGHT SNOW STARTING
DURING THE AFTERNOON AND ENDING LATE THIS EVENING. AT THE SURFACE...
HIGH PRESSURE OVERHEAD WILL MOVE EAST OF THE AREA THIS AFTERNOON
AHEAD OF THE CLIPPER LOW SYSTEM.
THE LATEST 12Z NAM SHOWS A FAIRLY DRY SYSTEM WITH ONLY LIGHT QPF
AMOUNTS OF LESS THAN 0.1 LIQUID...WTIH SNOW- LIQUID RATIOS OF 10
TO 12 TO ONE AS SHOWN BY THE 09Z/SREF. OTHER HI-RES MODELS ALL
AGREE ON TIMING THE SYSTEM ACROSS THE REGION THIS AFTERNOON AND
EVENING BUT DIFFER IN DETAILS OF SNOW AND ANY ATTENDANT SNOW
BANDING. THE 11Z 3KM HRRR IS TRENDING TO A WEAKER SYSTEM MOVING
THROUGH WITH LESS SNOWFALL POTENTIAL...WHEREAS THE 00Z 4KM NCEP
WRF NMM SHOWS A SLIGHTLY STRONG SYSTEM...ON A PAR WITH YESTERDAYS
CLIPPER.
CURRENT FORECAST HAD THE TIMING COVERED PRETTY WELL...AND I ONLY
MADE SOME MINOR ADJUSTMENTS TO THAT TIMING. FOR SNOWFALL AMOUNTS...
GIVING CURRENT SPEED OF THE CLIPPER...EXPECTING A 4 TO 6 HR PERIOD
WHERE OCCASSIONAL LIGHT SNOW WILL FALL. AIRMASS IS VERY DRY...
DULLES RAOB ONLY 0.18 INCHES...WITH FORECAST SOUNDINGS SHOWING AT
MOST 0.4 INCHES OF PRECIPITABLE WATER THIS AFTENROON AND EARLY
EVENING. DID NOT MAKE ANY CHANGES FOR CURRENT SNOW TOTAL GRAPHIC
FOR THE 930 AM UPDATE.
TEMPERATURES WILL BE UNSEASONABLY COLD TODAY MAINLY AT OR BELOW
FREEZING IN MOST LOCATIONS...AND AFTER LAST NIGHTS COLD READINGS
ANY SNOW THAT FALLS WILL STICK ON UNTREATED SURFACES.
&&
.SHORT TERM /7 PM THIS EVENING THROUGH 6 PM SUNDAY/...
THE UPPER LEVEL WAVE/CLIPPER SYSTEM WILL BE SCOOTING OFF QUICKLY
TO THE EAST DURING THE EVENING HOURS...ENDING THE SNOW THREAT FOR
ALL AREAS...EXCEPT IN THE WESTERN UPSLOPE AREAS OF WESTERN
MD/VA/WV.
FOR SUN...ANOTHER UPPER LEVEL DISTURBANCE CLIPPER LIKE SYSTEM
APPROACHES THE REGION DURING THE MORNING AND CROSSES DURING THE
AFTERNOON HOURS. THIS SYSTEM HAS A LITTLE MORE IN THE WAY OF UPPER
DYNAMICS ASSOCIATED WITH IT...AND WOULD EXPECT TO SEE A BAND OR
TWO OF SNOW SHOWERS PASS ACROSS THE REGION DURING THE AFTERNOON
HOURS. TEMPS ON SUN EXPECTED TO BE 4 TO 6 DEGREES WARMER ON SUN.
ANY SNOW BANDS THAT COME THROUGH COULD PRODUCE A QUICK COATING OF
SNOW...BUT TEMPS SHOULD BE ABOVE FREEZING IN MOST AREAS. WILL
CONTINUE TO MONITOR.
PREVIOUS DISCUSSIONS FOLLOW.
&&
.LONG TERM /SUNDAY NIGHT THROUGH FRIDAY/...
SUNDAY A SHEARED BUT POTENT SHORT WAVE WILL SLIDE EAST ACROSS THE
REGION...AND WE COULD SEE SOME SNOW SHOWERS WITH THAT. THE MAIN
THREAT WINDOW IS IN THE LATE MORNING THRU LATE AFTERNOON. ANY
ACCUM IS EXPECTED TO BE LESS THAN AN INCH...EXCEPT AROUND AN INCH
IN THE MOUNTAINS.
NEXT UP IS A CLIPPER MOVING EAST ACROSS THE MID ATLANTIC MONDAY
NIGHT WITH ANOTHER CHANCE AT A LIGHT ACCUMULATION. AND THIRD IS
ANOTHER CLIPPER PUSHING SOUTHEAST INTO NC WHICH BRINGS ANOTHER
CHANCE OF LIGHT ACCUMULATION ON TUESDAY NIGHT. THE GFS AND EURO
ARE IN GOOD AGREEMENT WITH THE TIMING OF BOTH OF THESE FEATURES
AND THEIR INTENSITIES.
AFTER THAT A SFC LOW IS SLATED TO CROSS TO OUR NORTH AND BRING A
COLD FRONT THROUGH US ON FRIDAY. BUT IT WILL NOT BE MUCH OF A COLD
FRONT AS RIDGING BUILDS IN QUICKLY BEHIND WITH MILDER TEMPS...AND
BASED ON THE LATEST WEEK TWO FORECASTS FROM THE NWS CLIMATE
PREDICTION CENTER...THOSE MILD TEMPS ARE EXPECTED TO DOMINATE THE
FOLLOWING WEEK.
&&
.AVIATION /15Z SATURDAY THROUGH WEDNESDAY/...
EXPECT A FEW PERIODS OF LIGHT SNOW TO DEVELOP THIS AFTERNOON AS
THE NEXT CLIPPER SYSTEM MOVES EAST. CIGS SHOULD DROP TO AROUND
3KFT AND VSBYS COULD LOWER BRIEFLY TO 1 TO 2 MILES. HAVE ADJST
TAFS TO REFLECT THIS. THE SNOW SHOULD BE SHORT-LIVED AND WILL BE
MOVING AWAY FROM THE AREA DURING THE 01-03Z TIMEFRAME THIS EVENING.
IFR CONDITIONS ARE POSSIBLE IN ANY SNOW SHOWERS ON
SUNDAY...AND AGAIN WITH SNOW SHOWERS WITH MON NIGHT AND TUE NIGHT
SHORT WAVES.
&&
.MARINE...
HIGH PRES TODAY WILL MOVE EAST IN ADVANCE OF THE CLIPPER SYSTEM.
WINDS COME AROUND TO S TO SW THIS AFTERNOON WITH A FEW 15 KT GUSTS
POSSIBLE. PERIODS OF LIGHT SNOW OVERSPREADING THE WATERS DURING
THE AFTERNOON BUT ENDING DURING THE MID EVENING HOURS.
ON SUN...ANOTHER UPPER LEVEL DISTURBANCE MOVES ACROSS THE WATER
DURING THE AFTERNOON. WINDS MAY INCREASE AFTER PASSAGE OF THIS
SYSTEM SUN AFTERNOON AND SMALL CRAFT ADV WINDS ARE EXPECTED SUNDAY
AFTERNOON INTO MONDAY AFTERNOON. THAT IS EXPECTED TO AGAIN BE THE
CASE ON WEDNESDAY AFTER THE CLIPPER.
&&
.LWX WATCHES/WARNINGS/ADVISORIES...
DC...NONE.
MD...NONE.
VA...NONE.
WV...NONE.
MARINE...SMALL CRAFT ADVISORY FROM 2 PM SUNDAY TO 3 PM EST MONDAY FOR
ANZ530>543.
&&
$$
SYNOPSIS...SMZ
NEAR TERM...SMZ
SHORT TERM...SMZ
LONG TERM...CAS
AVIATION...SMZ
MARINE...SMZ
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
950 PM EST SUN FEB 3 2013
.UPDATE...
ISSUED AT 949 PM EST SUN FEB 3 2013
UPSTREAM 00Z KINL SOUNDING SHOWED THAT RATHER SIGNIFICANT DRYING HAS
OCCURRED SINCE THE 12Z SOUNDING. OVERALL...IT`S NOT AN ENVIRONMENT
REALLY FAVORABLE FOR ANYTHING MUCH MORE THAN LIGHT LES. THIS DRIER
AIR HAS MADE AN IMPACT AS SATELLITE IMAGERY SHOWS A FAIR AMOUNT OF
DISTANCE BTWN THE MN SHORE AND LAKE EFFECT CLOUDS DEVELOPING OVER
THE LAKE. ALSO...WEBCAMS/SPOTTER REPORT FROM MOHAWK AND KCMX OB ALSO
INDICATE ONLY LIGHT LES IS OCCURRING. HAVE THUS CANCELLED THE ADVY
FOR THE WRN COUNTIES WITH ONLY AN INCH...MAYBE 2 OF ADDITIONAL SNOW
OVERNIGHT.
TO THE E...HEAVIER NW FLOW LES CONTINUES. AS IS TYPICAL...WRN MOST
BAND IS BECOMING A MORE DOMINANT BAND DUE TO ENHANCED CONVERGENCE
FROM LAND BREEZE OFF MARQUETTE COUNTY. THIS BAND IS STREAMING INTO
THE MUNISING/WETMORE SHINGLETON AREA. SPOTTER UNDER THIS BAND
REPORTED ABOUT AN INCH/HR SNOWFALL RATE. FARTHER E...ERN MOST BAND
ENHANCED BY CONVERGENCE FROM LAND BREEZE OFF ONTARIO IS STREAMING
INTO ERN WHITEFISH BAY. LATEST HIGH RES MODEL GUIDANCE REMAINS IN
AGREEMENT THAT WITH SOME WEAKENING OF THE GRADIENT WINDS...LAND
BREEZE OFF ONTARIO WILL MAKE SIGNIFICANT WESTWARD PROGRESS
OVERNIGHT...POSSIBLY TO AROUND GRAND MARAIS BY 12Z. THERE SHOULD BE
A HVY SNOW BAND ALONG THAT CONVERGENT ZONE AS IT SHIFTS W. WILL THUS
CONTINUE TO HIGHLIGHT THE AREA FROM MUNISING TO PINE STUMP JUNCTION
FOR HEAVIEST SNOWFALL OVERNIGHT INTO THE MORNING. WITH LAND BREEZE
OFF MARQUETTE COUNTY...A SECONDARY SNOWFALL MAX MAY OCCUR FROM AU
TRAIN/MUNISING AND TO POINTS SE FROM THERE.
&&
.SHORT TERM...(THIS EVENING THROUGH MONDAY)
ISSUED AT 358 PM EST SUN FEB 3 2013
12Z RAOBS/LATEST WV IMAGERY AND RUC ANALYSIS SHOW PERSISTENT DEEP
UPR TROF OVER E-CNTRL NAMERICA DOWNSTREAM OF HI AMPLITUDE RDG OFF
THE W COAST. A SHRTWV/ATTENDANT LO PRES TROF EMBEDDED IN THIS FLOW
CROSSED UPR MI THIS MRNG...DROPPING AS MUCH AS 3 TO 6 INCHES OF SN
IN AREAS NEAR LK SUP FAVORED FOR MOISTENING/UPSLOPE FLOW IN LLVL
W-NW WINDS. SINCE THE AIRMASS WAS SO DRY WITH PWAT NO MORE THAN
0.05-0.15 INCH...LOCATIONS AWAY FM LK MOISTENING SAW LESS THAN AN
INCH OF SN. IN THE WAKE OF THE TROF PASSAGE...A LLVL NW FLOW BTWN
THE DEPARTING TROF AND A HI PRES RDG MOVING INTO MN AND SHOWN BY THE
MQT VWP IS BRINGING A REINFORCING SHOT OF ARCTIC AIR WITH 12Z H85
TEMPS RANGING FM -20C AT GRB TO -24C AT INL AND -28C AT YPL. DESPITE
THE ABSOLUTE DRYNESS OF THE INCOMING AIRMASS WITH PWATS 0.05 TO 0.10
INCH AND LO INVRN BASE H9-875 SHOWN ON THE 12Z INL/YPL RAOBS...THESE
RAOBS INDICATE THE LOWER LYRS ARE MOIST ENUF IN A RELATIVE SENSE TO
SUSTAIN NMRS WIND PARALLEL LES BANDS SHOWN ON VSBL STLT IMAGERY.
AWAY FM THE NW WIND SN BELTS ESPECIALLY OVER THE SCNTRL WITH
DOWNSLOPE FLOW...DEEP LYR QVECTOR CNVGC/SUBSIDENCE IN THE WAKE OF
DEPARTING SHRTWV ARE CAUSING MOSUNNY CONDITIONS. BUT SFC TEMPS ARE
WELL BLO NORMAL.
TNGT...DEEP LYR QVECTOR DVGC/LARGER SCALE SUBSIDENCE IN THE WAKE OF
DEPARTING SHRTWV ARE FCST TO DOMINATE...AND FCST SDNGS SHOW INVRN
BASE FALLING TO 3-4K FT OVER THE W AND TO ARND 5K FT IN AREAS E OF
MQT. WITH SLOWLY SHIFTING /DIMINISHING NW LLVL FLOW OF ARCTIC AIR
DROPPING H85 TEMPS TO -20C TO -23C...EXPECT NMRS LES BANDS TO IMPACT
AREAS FAVORED BY NW WINDS. LONG FETCH INTO THE ERN CWA WL ALLOW FOR
MODIFICATION OF THE ARCTIC AIR...AND FCST PROFILES SHOW A RELATIVELY
DEEP DGZ WL OCCUPY A GOOD PORTION OF THE CONVECTIVE LYR. IN FACT...
THE 12Z NAM REMAINS QUITE CONSISTENT WITH EARLIER RUNS SHOWING SN/
WATER RATIOS OF 30:1 AT MUNISING THRU TNGT. A GOOD NUMBER OF THE
HIER RES MODELS ALSO INDICATE INCRSG LLVL CNVGC IN THE AREA E OF
MUNISING WITH DVLPMNT OF AN E LAND BREEZE FLOW OFF SE ONTARIO INTO
LUCE COUNTY. THIS COMBINATION OF FAVORABLE FACTORS WARRANTS
CONTINUING THE GOING LES WRNG FOR ALGER/NRN SCHOOLCRAFT/LUCE
COUNTIES. OVER THE W...RELATIVELY SHORT FETCH LENGTH OVER WRN LK SUP
SHORTENED FURTHER BY ICE BUILDUP OFF THE W SHORE WL TEND TO LIMIT
MODERATION OF THIS FRIGID AIRMASS. FCST PROFILES FOR THE WRN CWA
INDICATE THE DGZ OVER THE W WL OCCUPY ONLY THE LOWEST 1K FT OF SO OF
THE ATMOSPHERE. THIS LIMIT ON SN FLAKE SIZE SHOULD HOLD DOWN SN
ACCUMS. THE SOMEWHAT HEAVIER SN MIGHT FALL OVER ONTONAGON COUNTY
WITH MORE PERSISTENT LLVL CNVGC/HINT OF LAND BREEZE FLOW OFF NW WI.
WITH SLOWLY WEAKENING H925 WINDS...DIMINISHING BLSN MIGHT BE ENUF TO
ALLOW EARLY CANX OF LES ADVY OVER THE W AWAY FM ONTONAGON COUNTY.
BUT LEFT GOING ADVY ALONE FOR NOW EVEN THOUGH SN AMNTS MIGHT BE SUB
ADVY DUE TO EFFICIENT NATURE OF FINE SN FLAKES TO LIMIT VSBY.
MON...AS HI PRES RDG AXIS TO THE W SLIDES SLOWLY TO THE E...THE LLVL
FLOW IS PROGGED TO STEADILY BACK TO THE W BY LATE IN THE DAY.
ALTHOUGH H85 TEMPS ARE FCST TO RISE A FEW DEGREES TO -18C TO -21C BY
LATE IN THE DAY...INSTABILITY WL REMAIN MORE THAN SUFFICIENT FOR LES
TO CONTINUE. SLOWLY RISING H85 TEMPS MAY IMPROVE SN GROWTH OVER
THE W... BUT LINGERING LO INVRN BASE AND GENERAL ACYC NATURE OF THE
LLVL FLOW SHOULD ACT TO SUPPRESS THE SHSN INTENSITY. OVER THE E...
ALTHOUGH THE BANDS MIGHT BEGIN TO SHIFT TOWARD THE E...LINGERING
SHARP LLVL CNVGC IN AT LEAST PART OF THIS AREA WARRANTS MAINTAINING
GOING WRNG THRU THE DAY WITH FVRBL SN GROWTH PARAMETERS IN PLACE.
.LONG TERM...(MONDAY NIGHT THROUGH SUNDAY)
ISSUED AT 358 PM EST SUN FEB 3 2013
NO BIG CHANGES TO EXPECTED PATTERN SHIFT THAT OCCURS THROUGH THIS
WEEK AS COLD TROUGHING OVER EASTERN CONUS RETREATS INTO CANADA AS
FLOW BECOMES MORE ZONAL LATE THIS WEEK AND TURNS TO SPLIT FLOW
PATTERN BY NEXT WEEKEND. MAIN RESULT IS WARMER TEMPS RETURNING TO
UPR LAKES BY LATE THIS WEEK ALONG WITH A COUPLE CHANCES OF SYSTEM
SNOW ALONG THE WAY.
TO START THE LONG TERM ON MONDAY EVENING...EXPECT LK EFFECT OVER
THE EAST TO GRADUALLY FADE AWAY THROUGH THE NIGHT AS WINDS BACK AND
INVERSIONS CONTINUE TO LOWER. AFTER MIDNIGHT...MAJORITY OF SNOW
SHOWERS WILL BE TO THE EAST OF GRAND MARAIS INTO NORTHERN LUCE
COUNTY. MID CLOUDS AHEAD OF NEXT CLIPPER SYSTEM ALREADY WILL BE
SPILLING ACROSS CWA LATER MONDAY NIGHT WITH SOME SNOW PUSHING INTO
FAR WEST UPR MICHIGAN TOWARD DAYBREAK ON TUESDAY. TEMPS MAY TRY TO
PLUMMET QUICKLY MONDAY EVENING WELL BLO ZERO BEFORE RISING LATER.
COLDEST TEMPS WOULD BE OVER CNTRL AND EASTERN INTERIOR.
CLIPPER SYSTEM ALLUDED TO IS CURRENTLY PUSHING ASHORE OVER NORTHERN
BRITISH COLUMBIA. WAVE IS EXPECTED TO DIG FROM NORTHERN MN ACROSS WI
LATE MONDAY NIGHT THROUGH TUESDAY. THOUGH SFC TROUGH SLIDES SOUTH OF
UPR MICHIGAN...H85 TROUGH CROSSES UPR MICHIGAN THROUGH THE DAY ON
TUESDAY. EXPECT H85 TEMPERATURE AND MOISTURE ADVECTION ALONG WITH
DIVERGENCE ALOFT/H85-H7 FRONTOGENESIS TO SPREAD AREA OF LGT SNOW
ACROSS CWA. MIXING RATIOS LESS THAN 2G/KG AND SHORT DURATION OF
STEADY SNOW WILL LIMIT ACCUMS...BUT THERE IS A POTENTIAL FOR MORE
PERSISTENT FGEN TO RESULT IN A BIT MORE SNOW /2-3 INCHES/ OVER FAR
SCNTRL IMT-MNM-ESC. THIS MATCHES WELL WITH LATEST HPC WINTER WEATHER
GUIDANCE. ECMWF HAS BEEN CONSISTENT IN IMPACTING MOST OF CWA WITH
LGT SNOW. NAM HAS BEEN QUITE INCONSISTENT...PAINTING WIDESPREAD SNOW
OVER ALL CWA YDY AND HARDLY SHOWING ANY QPF WITH 12Z RUN TODAY. WE
HAVE NOTICED RECENTLY OVER LAST FEW WEEKS THAT WITH THESE CLIPPER
SYSTEMS MODELS HAVE HAD TENDENCY TO FORECAST HEAVIER SWATHS OF SNOW
FARTHER SOUTH LEADING UP TO SNOW EVENTS MORE ALONG STRONGER
925-850MB MOISTURE ADVECTION...BEFORE CORRECTING FARTHER TO THE
NORTH RIGHT BEFORE THE EVENT BEGINS. WILL PLAY THAT TREND WITH THIS
FORECAST AND GO WITH FARTHER NORTH ECMWF DEPICTION WITH QPF/SNOW.
12Z GFS HAS TRENDED THIS WAY AS WELL AND ACTUALLY SHOWS SFC LOW A
BIT FARTHER NORTH AS WELL.
AS SFC LOW OR AT LEAST TROUGHING MOVES INTO NORTHERN LOWER MICHIGAN
BY TUESDAY EVENING...WINDS BECOME ONSHORE NEAR LK SUPERIOR. SOME H85
AND EVEN H7 MOISTURE AROUND WITH H85 TEMPS DOWN BLO -13C. WINDS WILL
BE STEADILY BACKING FROM NORTH TO WEST-NORTHWEST THROUGH THE NIGHT.
SCT LK EFFECT SNOW SHOWERS SEEM REASONABLE ALONG LK SUPERIOR. SHOULD
NOT BE BIG DEAL THOUGH AS INVERSIONS QUICKLY LOWER AND WITH PLENTY
OF LOW-LEVEL WIND SHEAR. ISOLD SNOW SHOWERS END QUICKLY ON WEDNESDAY
MORNING ONCE WINDS BECOME MORE SOUTHERLY AHEAD OF NEXT CLIPPER
SYSTEM ENTERING NORTHERN PLAINS.
MODELS HAVE BEEN CONSISTENT IN SHOWING ANOTHER ROUND OF SNOW WITH
THAT CLIPPER AFFECTING UPPER LAKES REGION SOMETIME FROM AS EARLY AS
WEDNESDAY MORNING THROUGH THURSDAY. GEM-NH QUICKEST AS IT HAS
STRONGER H85 LOW OVER NORTHERN MN BY WEDNESDAY AFTN RESULTING IN
MORE MOISTURE AND TEMP ADVECTION AT H85 INTO UPR MICHIGAN. GFS A BIT
SLOWER...FAVORING MOST QPF ON WEDNESDAY NIGHT. ECMWF SLIGHTLY
SLOWER...BUT STILL HAS MAJORITY OF QPF ON WEDNESDAY
NIGHT...ESPECIALLY WEST/CNTRL. SYSTEM IS SIMILAR TO ONE THAT MOVES
THROUGH ON TUESDAY...EXCEPT THIS ONE IS LACKING UPR JET SUPPORT BUT
HAS MORE MOISTURE TO WORK WITH AS H7 MIXING RATIOS ARE 2.5-3.0 G/KG
FLOWING INTO UPR MICHIGAN. 00Z ECMWF WAS FAIRLY WET WITH
QPF...SHOWING OVER 0.4 INCH OVER CNTRL CWA. PREVIOUS RUNS OF ECMWF
AND NEW 12Z RUN NOT AS MOIST...WITH UP TO 0.3 INCH. GFS STAYING ON
THE DRIER SIDE...AROUND 0.15 INCH. SEEMS LIKE IT WILL BE WETTER SNOW
AS H85 TEMPS ARE WARMER THAN -10C AND H7 TEMPS ARE ONLY SLIGHLY
COLDER. COLDER BLYR TEMPS IN TEENS/LOWER 20S PROBABLY ALLOW SLR/S TO
END UP AROUND CLIMO CENTERED ON 15:1. AT FIRST GLANCE...LOW-END ADVY
SNOWS MAY OCCUR OVER PORTIONS OF CWA.
THIS SYSTEM IS STILL OVER NORTHERN PACIFIC WELL TO SOUTH OF ALLUTIAN
ISLANDS. PLENTY OF TIME TO LATCH ONTO SPECIFICS BUT ENOUGH EVIDENCE
PRESENT TO INCREASE POPS TO LIKELY. POPS MAY NEED INCREASING FOR
THURSDAY MORNING OVER THE EAST...BUT JUST KEPT HIGH CHANCE FOR NOW
AS MAJORITY OF SYSTEM SNOW WILL BE FINISHING UP BY THAT TIME. ONCE
LOW SLIDES BY BLYR WINDS BECOME ONSHORE ALONG LK SUPERIOR THU NIGHT
AND THEN BACK OFFSHORE ON FRIDAY. DECREASING MOISTURE AND LACK OF
VERY COLD AIR SHOULD KEEP ANY LK EFFECT LIMITED INTO FRIDAY. OTHER
STORY THURSDAY INTO FRIDAY WILL BE SIGNS THAT WE WILL BE AT LEAST
TEMPORARILY BUSTING OUT OF OUR COLDER WEATHER PATTERN OF LATE WITH
HIGHS BOTH DAYS UPR 20S TO NEAR 30 DEGREES. MODELS HAVE BEEN
INSISTENT THAT COULD SEE SOME SUNSHINE LATER FRIDAY...SO TEMPS MAY
END UP ABOVE FREEZING IN SOME AREAS. SIMILAR TEMPS WILL CONTINUE
INTO THE WEEKEND.
FINALLY...SIGNALS EMERGING IN MODELS/ENSEMBLES THAT AS FLOW BECOMES
SPLIT NEXT WEEKEND...A SOUTHERN STREAM SYSTEM WILL LIFT INTO GREAT
LAKES NEXT SUNDAY INTO MONDAY. STRENGTH OF SYSTEM DEPENDS ON IF
SOUTHERN WAVE BECOMES NEGATIVELY TILTED AND WHETHER ANY PHASING CAN
OCCUR WITH NORTHERN STREAM. FOR WHAT IT IS WORTH...12Z RUNS OF ECMWF
AND GFS SHOW GENEROUS AMOUNTS OF QPF OVER UPPER LAKES LATE NEXT
SUNDAY INTO MONDAY. MAY EVEN BE ENOUGH WARM AIR WRAPPED INTO THE
SYSTEM TO BRING CHANCE OF RAIN/FREEZING RAIN INTO UPR LAKES. DID GO
AHEAD AND MENTION RAIN/SNOW MIX OVER THE SOUTHERN CWA WHICH MATCHES
UP WELL WITH SURROUNDING OFFICES. ELSEWHERE...LOOKS LIKE A WET
SYSTEM SNOW WOULD IMPACT MUCH OF UPR MICHIGAN. A BIT PREMATURE TO
GET TOO HUNG UP ON DETAILS...BUT WILL BE SOMETHING TO WATCH AS WE GO
THROUGH THE UPCOMING WEEK.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z MONDAY EVENING)
ISSUED AT 626 PM EST SUN FEB 3 2013
AT KCMX...EXPECT IFR CONDITIONS TO DOMINATE THRU THIS FCST PERIOD
WITH NW FLOW OF ARCTIC AIR CONTINUING TO SUPPORT LAKE EFFECT SNOW
SHOWERS. OCNL LIFR CONDITIONS SHOULD CONTINUE THRU MID EVENING WITH
SOME BLOWING OF THE SMALL FINE SNOWFLAKES WHICH ARE EFFECTIVE AT
REDUCING VIS. WITH WIND DIMINISHING...THERE SHOULD BE LESS POTENTIAL
FOR LIFR CONDITIONS BY LATE EVENING. AS IS TYPICAL OF LAKE EFFECT
SNOW...CONDITIONS MAY BE HIGHLY VARIABLE AT TIMES.
AT KIWD...NW FLOW OVER THE LAKE WILL BE FIGHTING STRENGTHENING LAND
BREEZE OFF NW WI. AS A RESULT...KIWD WILL BE RIGHT ON THE EDGE OF
LAKE EFFECT CLOUDS/-SHSN. OPTED TO KEEP MVFR CONDITIONS AT KIWD THRU
THE MORNING BEFORE LARGER SCALE BACKING OF FLOW MAKES CLEARING MORE
LIKELY. THAT SAID...IT`S QUITE POSSIBLE MVFR CIGS COULD CLEAR OUT AT
ANYTIME TONIGHT GIVEN SUCH CLOSE PROXIMITY OF CLEAR SKIES TO THE W
OF KIWD.
AT KSAW...ALTHOUGH PASSING -SHSN/FLURRIES COULD BRING MVFR CIGS AT
TIMES...EXPECT VFR CONDITIONS TO PREVAIL THRU THIS FCST PERIOD WITH
DOWNSLOPING WNW FLOW.
&&
.MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 358 PM EST SUN FEB 3 2013
EXPECT PERIODS OF HEAVY FREEZING SPRAY INTO TONIGHT WITH NW WINDS UP
TO 25-30KTS ADVECTING ARCTIC AIR OVER THE WATER. AS THE NW WINDS
DIMINISH LATER TONIGHT WITH APPROACH OF A HI PRES RIDGE...THE HEAVY
FREEZING SPARY WILL GRADUALLY DIMINISH AS WELL. EXPECT WINDS TO STAY
MAINLY BLO 25 KTS THROUGH THE UPCOMING WEEK AS A SERIES OF CLIPPER
LOW PRESSURE TROUGHS MOVE ACROSS. TEMPERATURES WILL GRAUDALLY WARM SO
THERE WILL NOT BE MUCH IN WAY OF FREEZING SPRAY.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
LAKE EFFECT SNOW WARNING UNTIL 7 PM EST MONDAY FOR MIZ006-007-
085.
LAKE SUPERIOR...
HEAVY FREEZING SPRAY WARNING UNTIL 7 AM EST MONDAY FOR LSZ244-
245-248>251-264>267.
HEAVY FREEZING SPRAY WARNING UNTIL 1 AM EST /MIDNIGHT CST/
MONDAY FOR LSZ241>243-263.
LAKE MICHIGAN...
NONE.
&&
$$
UPDATE...ROLFSON
SHORT TERM...KC
LONG TERM...JLA
AVIATION...ROLFSON
MARINE...KC/JLA
AREA FORECAST DISCUSSION
NWS GRAND RAPIDS MI
703 PM EST SUN FEB 3 2013
.SYNOPSIS...
ISSUED AT 335 PM EST SUN FEB 3 2013
A CLIPPER WILL BRING SNOW TO FAR SOUTHERN LOWER MICHIGAN TONIGHT
AS LAKE EFFECT SNOW SHOWERS CONTINUE FOR AREAS NEAR LAKE MICHIGAN.
COLD WEATHER WILL CONTINUE THIS WEEK AND ANOTHER CHANCE OF SNOW
WILL ARRIVE LATE WEDNESDAY.
&&
.SHORT TERM...(THIS EVENING THROUGH TUESDAY NIGHT)
ISSUED AT 335 PM EST SUN FEB 3 2013
CLIPPER WILL BRING SOME SNOW TO THE I-94 CORRIDOR LATE TONIGHT AND
MONDAY MORNING. LATEST HRRR AND 12Z MODEL GUIDANCE SUGGEST HEAVIER
STRIPE OF F-GEN SNOWS WILL MISS OUR FORECAST AREA TO THE SOUTH BUT
EXPECT AT LEAST A COUPLE INCHES ACROSS SOUTHERN CALHOUN AND
JACKSON COUNTIES...JUST ENOUGH TO IMPACT THE MONDAY MORNING COMMUTE.
WENT WITH A WINTER WEATHER ADVISORY FOR JACKSON AND CALHOUN SINCE
THIS WILL BE A SYNOPTIC EVENT...WHILE CONTINUING THE LAKE EFFECT
SNOW ADVISORY FOR WESTERN COUNTIES DUE TO LAKE ACCUMS THERE TODAY
AND TONIGHT.
THE CLIPPER MOVES EAST WEDNESDAY AFTERNOON WITH JUST SOME RATHER
LIGHT LAKE EFFECT SNOW SHOWERS LEFT IN ITS WAKE. THE YET ANOTHER
CLIPPER APPROACHES IN FAST NW FLOW FOR TUESDAY AFTERNOON AND
EVENING. THE SFC LOW MOVES NORTH OF THE FORECAST AREA BUT SOME
CONVERGENCE AND LAKE ENHANCEMENT EXPECTED TO DROP MORE SNOW ACROSS
THE NORTHWEST FORECAST AREA...PERHAPS ENOUGH FOR AN ADVISORY.
.LONG TERM...(WEDNESDAY THROUGH SUNDAY)
ISSUED AT 335 PM EST SUN FEB 3 2013
SEASONABLE TEMPS ARE ANTICIPATED WEDNESDAY BEFORE TEMPS MODERATE
SLIGHTLY LATE IN THE WEEK AND FOR NEXT WEEKEND. DRY CONDITIONS ARE
ANTICIPATED WEDNESDAY WITH A HIGH PRESSURE RIDGE IN CONTROL BEFORE A
LOW PRESSURE SYSTEM BRINGS A CHC OF SNOW LATE WEDNESDAY NIGHT. A MIX
OF RAIN AND SNOW IS POSSIBLE FOR THURSDAY.
A HIGH PRESSURE RIDGE WILL BRING DRY WX FRIDAY INTO SATURDAY BEFORE
THE NEXT LOW PRESSURE SYSTEM BRINGS ANOTHER CHC FOR MIXED PCPN LATE
NEXT WEEKEND.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z MONDAY EVENING)
ISSUED AT 700 PM EST SUN FEB 3 2013
THE LAKE EFFECT SNOW SHOWERS WILL CONTINUE TO DIMINISH FOR A FEW
HOURS THIS EVENING. THIS WILL LEAD TO MAINLY MVFR TO VFR
CONDITIONS. BY 08Z...THE NEXT CLIPPER SYSTEM WILL MOVE IN FROM THE
WEST. THIS SYSTEM WILL ADD MOISTURE TO THE EXISTING LAKE EFFECT
CAUSING A RETURN OF THE IFR AND LOWER CONDITIONS. AFTER A PERIOD
OF STEADY SNOW WITH LOW AVIATION CONDITIONS...CONDITIONS WILL
IMPROVE AFTER 18Z.
&&
.MARINE...
ISSUED AT 335 PM EST SUN FEB 3 2013
ICE WILL CONTINUE TO ACCUMULATE ON THE LAKES AND CHANNELS THE NEXT
COUPLE DAYS. EXPECT THE WAVES AND WINDS TO DECREASE ENOUGH ON
MONDAY TO LET THE SCA EXPIRE.
&&
.HYDROLOGY...
ISSUED AT 335 PM EST SUN FEB 3 2013
COLD WEATHER WILL HOLD ON MUCH OF THIS WEEK. A THAW IS EXPECTED
NEXT WEEKEND. LOOKING FURTHER AHEAD...BY MONDAY LOW PRESSURE
TAKING A TRACK ACROSS NORTHERN MICHIGAN COULD BRING ENOUGH RAIN
AND SNOW MELT TO CAUSE ANOTHER ROUND OF PROBLEMS WITH ICE BREAKUP
ON THE RIVERS.
&&
.GRR WATCHES/WARNINGS/ADVISORIES...
MI...LAKE EFFECT SNOW ADVISORY UNTIL 7 PM EST MONDAY FOR MIZ056-064-
071-072.
WINTER WEATHER ADVISORY FROM 4 AM TO 1 PM EST MONDAY FOR MIZ073-
074.
LM...SMALL CRAFT ADVISORY UNTIL 7 AM EST MONDAY FOR LMZ844>849.
&&
$$
SYNOPSIS...OSTUNO
SHORT TERM...OSTUNO
LONG TERM...LAURENS
AVIATION...MJS
HYDROLOGY...OSTUNO
MARINE...OSTUNO
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
626 PM EST SUN FEB 3 2013
.SHORT TERM...(THIS EVENING THROUGH MONDAY)
ISSUED AT 358 PM EST SUN FEB 3 2013
12Z RAOBS/LATEST WV IMAGERY AND RUC ANALYSIS SHOW PERSISTENT DEEP
UPR TROF OVER E-CNTRL NAMERICA DOWNSTREAM OF HI AMPLITUDE RDG OFF
THE W COAST. A SHRTWV/ATTENDANT LO PRES TROF EMBEDDED IN THIS FLOW
CROSSED UPR MI THIS MRNG...DROPPING AS MUCH AS 3 TO 6 INCHES OF SN
IN AREAS NEAR LK SUP FAVORED FOR MOISTENING/UPSLOPE FLOW IN LLVL
W-NW WINDS. SINCE THE AIRMASS WAS SO DRY WITH PWAT NO MORE THAN
0.05-0.15 INCH...LOCATIONS AWAY FM LK MOISTENING SAW LESS THAN AN
INCH OF SN. IN THE WAKE OF THE TROF PASSAGE...A LLVL NW FLOW BTWN
THE DEPARTING TROF AND A HI PRES RDG MOVING INTO MN AND SHOWN BY THE
MQT VWP IS BRINGING A REINFORCING SHOT OF ARCTIC AIR WITH 12Z H85
TEMPS RANGING FM -20C AT GRB TO -24C AT INL AND -28C AT YPL. DESPITE
THE ABSOLUTE DRYNESS OF THE INCOMING AIRMASS WITH PWATS 0.05 TO 0.10
INCH AND LO INVRN BASE H9-875 SHOWN ON THE 12Z INL/YPL RAOBS...THESE
RAOBS INDICATE THE LOWER LYRS ARE MOIST ENUF IN A RELATIVE SENSE TO
SUSTAIN NMRS WIND PARALLEL LES BANDS SHOWN ON VSBL STLT IMAGERY.
AWAY FM THE NW WIND SN BELTS ESPECIALLY OVER THE SCNTRL WITH
DOWNSLOPE FLOW...DEEP LYR QVECTOR CNVGC/SUBSIDENCE IN THE WAKE OF
DEPARTING SHRTWV ARE CAUSING MOSUNNY CONDITIONS. BUT SFC TEMPS ARE
WELL BLO NORMAL.
TNGT...DEEP LYR QVECTOR DVGC/LARGER SCALE SUBSIDENCE IN THE WAKE OF
DEPARTING SHRTWV ARE FCST TO DOMINATE...AND FCST SDNGS SHOW INVRN
BASE FALLING TO 3-4K FT OVER THE W AND TO ARND 5K FT IN AREAS E OF
MQT. WITH SLOWLY SHIFTING /DIMINISHING NW LLVL FLOW OF ARCTIC AIR
DROPPING H85 TEMPS TO -20C TO -23C...EXPECT NMRS LES BANDS TO IMPACT
AREAS FAVORED BY NW WINDS. LONG FETCH INTO THE ERN CWA WL ALLOW FOR
MODIFICATION OF THE ARCTIC AIR...AND FCST PROFILES SHOW A RELATIVELY
DEEP DGZ WL OCCUPY A GOOD PORTION OF THE CONVECTIVE LYR. IN FACT...
THE 12Z NAM REMAINS QUITE CONSISTENT WITH EARLIER RUNS SHOWING SN/
WATER RATIOS OF 30:1 AT MUNISING THRU TNGT. A GOOD NUMBER OF THE
HIER RES MODELS ALSO INDICATE INCRSG LLVL CNVGC IN THE AREA E OF
MUNISING WITH DVLPMNT OF AN E LAND BREEZE FLOW OFF SE ONTARIO INTO
LUCE COUNTY. THIS COMBINATION OF FAVORABLE FACTORS WARRANTS
CONTINUING THE GOING LES WRNG FOR ALGER/NRN SCHOOLCRAFT/LUCE
COUNTIES. OVER THE W...RELATIVELY SHORT FETCH LENGTH OVER WRN LK SUP
SHORTENED FURTHER BY ICE BUILDUP OFF THE W SHORE WL TEND TO LIMIT
MODERATION OF THIS FRIGID AIRMASS. FCST PROFILES FOR THE WRN CWA
INDICATE THE DGZ OVER THE W WL OCCUPY ONLY THE LOWEST 1K FT OF SO OF
THE ATMOSPHERE. THIS LIMIT ON SN FLAKE SIZE SHOULD HOLD DOWN SN
ACCUMS. THE SOMEWHAT HEAVIER SN MIGHT FALL OVER ONTONAGON COUNTY
WITH MORE PERSISTENT LLVL CNVGC/HINT OF LAND BREEZE FLOW OFF NW WI.
WITH SLOWLY WEAKENING H925 WINDS...DIMINISHING BLSN MIGHT BE ENUF TO
ALLOW EARLY CANX OF LES ADVY OVER THE W AWAY FM ONTONAGON COUNTY.
BUT LEFT GOING ADVY ALONE FOR NOW EVEN THOUGH SN AMNTS MIGHT BE SUB
ADVY DUE TO EFFICIENT NATURE OF FINE SN FLAKES TO LIMIT VSBY.
MON...AS HI PRES RDG AXIS TO THE W SLIDES SLOWLY TO THE E...THE LLVL
FLOW IS PROGGED TO STEADILY BACK TO THE W BY LATE IN THE DAY.
ALTHOUGH H85 TEMPS ARE FCST TO RISE A FEW DEGREES TO -18C TO -21C BY
LATE IN THE DAY...INSTABILITY WL REMAIN MORE THAN SUFFICIENT FOR LES
TO CONTINUE. SLOWLY RISING H85 TEMPS MAY IMPROVE SN GROWTH OVER
THE W... BUT LINGERING LO INVRN BASE AND GENERAL ACYC NATURE OF THE
LLVL FLOW SHOULD ACT TO SUPPRESS THE SHSN INTENSITY. OVER THE E...
ALTHOUGH THE BANDS MIGHT BEGIN TO SHIFT TOWARD THE E...LINGERING
SHARP LLVL CNVGC IN AT LEAST PART OF THIS AREA WARRANTS MAINTAINING
GOING WRNG THRU THE DAY WITH FVRBL SN GROWTH PARAMETERS IN PLACE.
.LONG TERM...(MONDAY NIGHT THROUGH SUNDAY)
ISSUED AT 358 PM EST SUN FEB 3 2013
NO BIG CHANGES TO EXPECTED PATTERN SHIFT THAT OCCURS THROUGH THIS
WEEK AS COLD TROUGHING OVER EASTERN CONUS RETREATS INTO CANADA AS
FLOW BECOMES MORE ZONAL LATE THIS WEEK AND TURNS TO SPLIT FLOW
PATTERN BY NEXT WEEKEND. MAIN RESULT IS WARMER TEMPS RETURNING TO
UPR LAKES BY LATE THIS WEEK ALONG WITH A COUPLE CHANCES OF SYSTEM
SNOW ALONG THE WAY.
TO START THE LONG TERM ON MONDAY EVENING...EXPECT LK EFFECT OVER
THE EAST TO GRADUALLY FADE AWAY THROUGH THE NIGHT AS WINDS BACK AND
INVERSIONS CONTINUE TO LOWER. AFTER MIDNIGHT...MAJORITY OF SNOW
SHOWERS WILL BE TO THE EAST OF GRAND MARAIS INTO NORTHERN LUCE
COUNTY. MID CLOUDS AHEAD OF NEXT CLIPPER SYSTEM ALREADY WILL BE
SPILLING ACROSS CWA LATER MONDAY NIGHT WITH SOME SNOW PUSHING INTO
FAR WEST UPR MICHIGAN TOWARD DAYBREAK ON TUESDAY. TEMPS MAY TRY TO
PLUMMET QUICKLY MONDAY EVENING WELL BLO ZERO BEFORE RISING LATER.
COLDEST TEMPS WOULD BE OVER CNTRL AND EASTERN INTERIOR.
CLIPPER SYSTEM ALLUDED TO IS CURRENTLY PUSHING ASHORE OVER NORTHERN
BRITISH COLUMBIA. WAVE IS EXPECTED TO DIG FROM NORTHERN MN ACROSS WI
LATE MONDAY NIGHT THROUGH TUESDAY. THOUGH SFC TROUGH SLIDES SOUTH OF
UPR MICHIGAN...H85 TROUGH CROSSES UPR MICHIGAN THROUGH THE DAY ON
TUESDAY. EXPECT H85 TEMPERATURE AND MOISTURE ADVECTION ALONG WITH
DIVERGENCE ALOFT/H85-H7 FRONTOGENESIS TO SPREAD AREA OF LGT SNOW
ACROSS CWA. MIXING RATIOS LESS THAN 2G/KG AND SHORT DURATION OF
STEADY SNOW WILL LIMIT ACCUMS...BUT THERE IS A POTENTIAL FOR MORE
PERSISTENT FGEN TO RESULT IN A BIT MORE SNOW /2-3 INCHES/ OVER FAR
SCNTRL IMT-MNM-ESC. THIS MATCHES WELL WITH LATEST HPC WINTER WEATHER
GUIDANCE. ECMWF HAS BEEN CONSISTENT IN IMPACTING MOST OF CWA WITH
LGT SNOW. NAM HAS BEEN QUITE INCONSISTENT...PAINTING WIDESPREAD SNOW
OVER ALL CWA YDY AND HARDLY SHOWING ANY QPF WITH 12Z RUN TODAY. WE
HAVE NOTICED RECENTLY OVER LAST FEW WEEKS THAT WITH THESE CLIPPER
SYSTEMS MODELS HAVE HAD TENDENCY TO FORECAST HEAVIER SWATHS OF SNOW
FARTHER SOUTH LEADING UP TO SNOW EVENTS MORE ALONG STRONGER
925-850MB MOISTURE ADVECTION...BEFORE CORRECTING FARTHER TO THE
NORTH RIGHT BEFORE THE EVENT BEGINS. WILL PLAY THAT TREND WITH THIS
FORECAST AND GO WITH FARTHER NORTH ECMWF DEPICTION WITH QPF/SNOW.
12Z GFS HAS TRENDED THIS WAY AS WELL AND ACTUALLY SHOWS SFC LOW A
BIT FARTHER NORTH AS WELL.
AS SFC LOW OR AT LEAST TROUGHING MOVES INTO NORTHERN LOWER MICHIGAN
BY TUESDAY EVENING...WINDS BECOME ONSHORE NEAR LK SUPERIOR. SOME H85
AND EVEN H7 MOISTURE AROUND WITH H85 TEMPS DOWN BLO -13C. WINDS WILL
BE STEADILY BACKING FROM NORTH TO WEST-NORTHWEST THROUGH THE NIGHT.
SCT LK EFFECT SNOW SHOWERS SEEM REASONABLE ALONG LK SUPERIOR. SHOULD
NOT BE BIG DEAL THOUGH AS INVERSIONS QUICKLY LOWER AND WITH PLENTY
OF LOW-LEVEL WIND SHEAR. ISOLD SNOW SHOWERS END QUICKLY ON WEDNESDAY
MORNING ONCE WINDS BECOME MORE SOUTHERLY AHEAD OF NEXT CLIPPER
SYSTEM ENTERING NORTHERN PLAINS.
MODELS HAVE BEEN CONSISTENT IN SHOWING ANOTHER ROUND OF SNOW WITH
THAT CLIPPER AFFECTING UPPER LAKES REGION SOMETIME FROM AS EARLY AS
WEDNESDAY MORNING THROUGH THURSDAY. GEM-NH QUICKEST AS IT HAS
STRONGER H85 LOW OVER NORTHERN MN BY WEDNESDAY AFTN RESULTING IN
MORE MOISTURE AND TEMP ADVECTION AT H85 INTO UPR MICHIGAN. GFS A BIT
SLOWER...FAVORING MOST QPF ON WEDNESDAY NIGHT. ECMWF SLIGHTLY
SLOWER...BUT STILL HAS MAJORITY OF QPF ON WEDNESDAY
NIGHT...ESPECIALLY WEST/CNTRL. SYSTEM IS SIMILAR TO ONE THAT MOVES
THROUGH ON TUESDAY...EXCEPT THIS ONE IS LACKING UPR JET SUPPORT BUT
HAS MORE MOISTURE TO WORK WITH AS H7 MIXING RATIOS ARE 2.5-3.0 G/KG
FLOWING INTO UPR MICHIGAN. 00Z ECMWF WAS FAIRLY WET WITH
QPF...SHOWING OVER 0.4 INCH OVER CNTRL CWA. PREVIOUS RUNS OF ECMWF
AND NEW 12Z RUN NOT AS MOIST...WITH UP TO 0.3 INCH. GFS STAYING ON
THE DRIER SIDE...AROUND 0.15 INCH. SEEMS LIKE IT WILL BE WETTER SNOW
AS H85 TEMPS ARE WARMER THAN -10C AND H7 TEMPS ARE ONLY SLIGHLY
COLDER. COLDER BLYR TEMPS IN TEENS/LOWER 20S PROBABLY ALLOW SLR/S TO
END UP AROUND CLIMO CENTERED ON 15:1. AT FIRST GLANCE...LOW-END ADVY
SNOWS MAY OCCUR OVER PORTIONS OF CWA.
THIS SYSTEM IS STILL OVER NORTHERN PACIFIC WELL TO SOUTH OF ALLUTIAN
ISLANDS. PLENTY OF TIME TO LATCH ONTO SPECIFICS BUT ENOUGH EVIDENCE
PRESENT TO INCREASE POPS TO LIKELY. POPS MAY NEED INCREASING FOR
THURSDAY MORNING OVER THE EAST...BUT JUST KEPT HIGH CHANCE FOR NOW
AS MAJORITY OF SYSTEM SNOW WILL BE FINISHING UP BY THAT TIME. ONCE
LOW SLIDES BY BLYR WINDS BECOME ONSHORE ALONG LK SUPERIOR THU NIGHT
AND THEN BACK OFFSHORE ON FRIDAY. DECREASING MOISTURE AND LACK OF
VERY COLD AIR SHOULD KEEP ANY LK EFFECT LIMITED INTO FRIDAY. OTHER
STORY THURSDAY INTO FRIDAY WILL BE SIGNS THAT WE WILL BE AT LEAST
TEMPORARILY BUSTING OUT OF OUR COLDER WEATHER PATTERN OF LATE WITH
HIGHS BOTH DAYS UPR 20S TO NEAR 30 DEGREES. MODELS HAVE BEEN
INSISTENT THAT COULD SEE SOME SUNSHINE LATER FRIDAY...SO TEMPS MAY
END UP ABOVE FREEZING IN SOME AREAS. SIMILAR TEMPS WILL CONTINUE
INTO THE WEEKEND.
FINALLY...SIGNALS EMERGING IN MODELS/ENSEMBLES THAT AS FLOW BECOMES
SPLIT NEXT WEEKEND...A SOUTHERN STREAM SYSTEM WILL LIFT INTO GREAT
LAKES NEXT SUNDAY INTO MONDAY. STRENGTH OF SYSTEM DEPENDS ON IF
SOUTHERN WAVE BECOMES NEGATIVELY TILTED AND WHETHER ANY PHASING CAN
OCCUR WITH NORTHERN STREAM. FOR WHAT IT IS WORTH...12Z RUNS OF ECMWF
AND GFS SHOW GENEROUS AMOUNTS OF QPF OVER UPPER LAKES LATE NEXT
SUNDAY INTO MONDAY. MAY EVEN BE ENOUGH WARM AIR WRAPPED INTO THE
SYSTEM TO BRING CHANCE OF RAIN/FREEZING RAIN INTO UPR LAKES. DID GO
AHEAD AND MENTION RAIN/SNOW MIX OVER THE SOUTHERN CWA WHICH MATCHES
UP WELL WITH SURROUNDING OFFICES. ELSEWHERE...LOOKS LIKE A WET
SYSTEM SNOW WOULD IMPACT MUCH OF UPR MICHIGAN. A BIT PREMATURE TO
GET TOO HUNG UP ON DETAILS...BUT WILL BE SOMETHING TO WATCH AS WE GO
THROUGH THE UPCOMING WEEK.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z MONDAY EVENING)
ISSUED AT 626 PM EST SUN FEB 3 2013
AT KCMX...EXPECT IFR CONDITIONS TO DOMINATE THRU THIS FCST PERIOD
WITH NW FLOW OF ARCTIC AIR CONTINUING TO SUPPORT LAKE EFFECT SNOW
SHOWERS. OCNL LIFR CONDITIONS SHOULD CONTINUE THRU MID EVENING WITH
SOME BLOWING OF THE SMALL FINE SNOWFLAKES WHICH ARE EFFECTIVE AT
REDUCING VIS. WITH WIND DIMINISHING...THERE SHOULD BE LESS POTENTIAL
FOR LIFR CONDITIONS BY LATE EVENING. AS IS TYPICAL OF LAKE EFFECT
SNOW...CONDITIONS MAY BE HIGHLY VARIABLE AT TIMES.
AT KIWD...NW FLOW OVER THE LAKE WILL BE FIGHTING STRENGTHENING LAND
BREEZE OFF NW WI. AS A RESULT...KIWD WILL BE RIGHT ON THE EDGE OF
LAKE EFFECT CLOUDS/-SHSN. OPTED TO KEEP MVFR CONDITIONS AT KIWD THRU
THE MORNING BEFORE LARGER SCALE BACKING OF FLOW MAKES CLEARING MORE
LIKELY. THAT SAID...IT`S QUITE POSSIBLE MVFR CIGS COULD CLEAR OUT AT
ANYTIME TONIGHT GIVEN SUCH CLOSE PROXIMITY OF CLEAR SKIES TO THE W
OF KIWD.
AT KSAW...ALTHOUGH PASSING -SHSN/FLURRIES COULD BRING MVFR CIGS AT
TIMES...EXPECT VFR CONDITIONS TO PREVAIL THRU THIS FCST PERIOD WITH
DOWNSLOPING WNW FLOW.
&&
.MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 358 PM EST SUN FEB 3 2013
EXPECT PERIODS OF HEAVY FREEZING SPRAY INTO TONIGHT WITH NW WINDS UP
TO 25-30KTS ADVECTING ARCTIC AIR OVER THE WATER. AS THE NW WINDS
DIMINISH LATER TONIGHT WITH APPROACH OF A HI PRES RIDGE...THE HEAVY
FREEZING SPARY WILL GRADUALLY DIMINISH AS WELL. EXPECT WINDS TO STAY
MAINLY BLO 25 KTS THROUGH THE UPCOMING WEEK AS A SERIES OF CLIPPER
LOW PRESSURE TROUGHS MOVE ACROSS. TEMPERATURES WILL GRAUDALLY WARM SO
THERE WILL NOT BE MUCH IN WAY OF FREEZING SPRAY.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
LAKE EFFECT SNOW ADVISORY UNTIL 7 AM EST MONDAY FOR MIZ001>003-
084.
LAKE EFFECT SNOW WARNING UNTIL 7 PM EST MONDAY FOR MIZ006-007-
085.
LAKE SUPERIOR...
HEAVY FREEZING SPRAY WARNING UNTIL 7 AM EST MONDAY FOR
LSZ249>251-266-267.
HEAVY FREEZING SPRAY WARNING UNTIL 7 AM EST MONDAY FOR LSZ244-
245-248-264-265.
HEAVY FREEZING SPRAY WARNING UNTIL 1 AM EST /MIDNIGHT CST/
MONDAY FOR LSZ241>243-263.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...KC
LONG TERM...JLA
AVIATION...ROLFSON
MARINE...KC/JLA
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
429 PM EST SAT FEB 2 2013
.SHORT TERM...(THIS EVENING THROUGH SUNDAY)
ISSUED AT 423 PM EST SAT FEB 2 2013
12Z RAOBS/LATEST WV IMAGERY AND RUC ANALYSIS SHOW PERSISTENT DEEP
UPR TROF OVER E-CENTRL NAMERICA DOWNSTREAM OF HI AMPLITUDE UPR RDG
ALONG THE W COAST. SHRTWV EMBEDDED IN THE NW FLOW ALF PASSED OVER
THE UPR LKS THIS MRNG...BUT SHRTWV RDG/DNVA/DEEP LYR QVECTOR CNVGC
IN ITS WAKE IS DOMINATING THE CWA THIS AFTN. ALTHOUGH LES CONTINUES
IN THE NW WIND SN BELTS WITH H85 TEMPS NOT FAR FM -20C...THESE
NEGATIVE DYNAMICS THAT ARE DROPPING INVRN BASE TOWARD H9 PER RUC
ANALYSIS AND ARRIVAL OF LLVL ACYC FLOW AS WELL AS VERY DRY AIRMASS
UPWIND OF LK SUP /12Z PWAT AT INL AND YPL WAS ABOUT 0.06 INCH/ ARE
LIMITING THE INTENSITY/COVERAGE OF THE BANDS. FARTHER UPSTREAM...
THERE ARE TWO SHRTWVS DIGGING SEWD THRU THE NW FLOW ALF. THE FIRST
IS DIVING INTO THE NRN PLAINS. THE SECOND DISTURBANCE WHICH WL HAVE
A MORE DIRECT IMPACT IS HEADING SSEWD THRU NRN MANITOBA.
LATE TODAY/TNGT...AS SFC RDG AXIS IN THE WAKE OF DEPARTING SHRTWV
PASSES SEWD THRU THE FA THIS EVNG...WINDS WL BACK STEADILY TO THE SW
THRU THIS EVNG. LINGERING LES BANDS WL BE SHIFTING STEADILY WITH THE
FLOW...AND IN CONCERT WITH MORE ACYC FLOW/LOWERING INVRN BASE LIMIT
ANY ADDITIONAL SN ACCUMS. MEANWHILE...FIRST UPSTREAM SHRTWV IS
PROGGED TO HEAD SEWD THRU THE UPR MS RIVER VALLEY. SINCE THE SHARPER
DPVA/DEEP LYR QVECTOR CNVGC/DEEPER MSTR WL PASS TO THE SW OF THE WI
BORDER...EXPECT THE BULK OF ANY ACCOMPANYING PCPN TO REMAIN IN WI
EVEN THOUGH SOME CLDS WL ARRIVE. AREA OF SHARPER DPVA/QVECTOR CNVGC/
MSTR ASSOCIATED WITH 2ND SHRTWV WL ARRIVE AFT MIDNGT. DRYNESS OF
AIRMASS WL LIMIT ANY LARGER SCALE PCPN...BUT ARRIVAL OF ACCOMPANYING
LO PRES TROF OVER THE NW ZNS LATE/WSHFT TO THE W-NW THAT WL BRING
ABOUT SOME LK ENHANCEMENT IN THE PRESENCE OF H85 TEMPS ARND -18C/
DEEP MSTR JUSTIFIES GOING CATEGORICAL POPS IN THAT AREA. SINCE 12Z
NAM FCST PROFILE FOR CMX SHOWS UVV MAX WITHIN DENDRITIC SN GROWTH
LYR...THERE MAY BE A PERIOD OF HEAVY SHSN JUST BEFORE 12Z THAT
COINCIDES WITH THE ARRIVAL OF THE TROF/SHARPER LLVL CNVGC. AS FOR
TEMPS...EXPECT READINGS TO FALL OFF RATHER QUICKLY THIS EVNG TOWARD
THE LOWER END OF GUIDANCE BUT THEN FALL ONLY SLOWLY OR PERHAPS RISE
WITH ARRIVAL OF MORE CLDS.
SUN...2ND SHRTWV IS FCST TO TRACK THRU LK SUP/ADJOINING ONTARIO ON
SUN MRNG...WITH ATTENDANT SFC TROF/WSHFT TO THE NW SWINGING ACRS THE
ERN CWA IN THE 15Z-18Z TIME. IN ITS WAKE...DNVA/LARGER SCALE QVECTOR
DVGC WL DOMINATE...DROPPING INVRN BASE OVER THE W TO 4-5K FT BY 18Z
BUT NOT OVER THE E UNTIL NEAR 00Z. SINCE THE INCOMING AIRMASS WL BE
QUITE CHILLY WITH H85 TEMPS PROGGED TO FALL AS LO AS -23C OVER THE W
LATE IN THE DAY...RATHER SHORT FETCH LENGTH OVER THE W HALF OF LK
SUP...SHORTENED EVEN FURTHER BY RECENT ICE BUILDUP ALONG THE W SHORE
OF THE CWA...WL LIMIT LK MODERATION. WITH THE DGZ CONFINED TO ONLY A
SHALLOW NEAR SFC LYR...EXPECT SMALL SN FLAKE SIZE AND RATHER LIMITED
SN ACCUMS AFT THE PASSAGE OF THE TROF/HEAVIER SN BAND EARLY. EVEN
THOUGH H925 NW WINDS IN THE WAKE OF THE TROF ARE FCST TO BE NO HIER
THAN ABOUT 25KT WHICH WOULD TEND TO LIMIT THE MAGNITUDE OF ANY
BLSN...PRESENCE OF SN COVERED ICE OFFSHORE WL LIKELY ENHANCE THE
VSBY RESTRICTION. FOR THE W...OPTED TO GO WITH AN LES ADVY FOR
ONTONAGON/HOUGHTON/KEWEENAW COUNTIES BEGINNING AT 09Z AND EXTENDING
THRU THE DAY. FOR AREAS E OF MQT...EXPECT A PERIOD OF HEAVIER SHSN
TO DVLP IN THE MRNG WITH PASSAGE OF TROF AND THEN MORE SUSTAINED
HEAVIER SHSN IN PREVAILING NW FLOW THRU THE AFTN. FCST PROFILE SHOW
DEEPER DGZ MAINTAINED BY MORE LK MOISTENING WL CAUSE BIGGER SN
FLAKES/HIER SN ACCUMS THAN OVER THE W. FOR ALGER/NRN SCHOOLCRAFT/
LUCE COUNTIES...OPTED TO BEGIN LONG DURATION LES WRNG AT 15Z. OVER
THE CENTRAL ZNS WITH DOWNSLOPE FLOW/LIMITED ABSOLUTE MSTR...THERE
WL BE NOTHING MORE THAN ISOLD-SCT -SHSN ASSOCIATED WITH THE TROF
PASSAGE.
.LONG TERM...(SUNDAY NIGHT THROUGH SATURDAY)
ISSUED AT 423 PM EST SAT FEB 2 2013
UPPER TROUGH AXIS CENTERED OVER NORTHER HUDSON BAY FORECAST TO OPEN
UP AND LIFT FARTHER NORTH INTO NUNAVUT CANADA. RESULT IS TROUGH AND
COLD AIR OVER GREAT LAKES TO BEGIN THE PERIOD EASES MID-LATE WEEK.
BY NEXT WEEKEND...HEIGHTS AND TEMPS ARE ON THE RISE OVER MUCH OF
EASTERN CONUS OUT AHEAD OF DEEPENING TROUGH OVER SOUTHWEST CONUS.
MEDIUM RANGE MODELS /GFS/ECMWF/GEM-NH/UKMET/ IN GREAT AGREEMENT
WITH LARGER SCALE PATTERN THROUGH NEXT WEEK...LEADING TO HIGHER THAN
NORMAL CONFIDENCE FOR MUCH OF THE FORECAST.
NORTHWEST FLOW ALOFT KEEPS COLD AIR IN OVER THE AREA THROUGH AT
LEAST MIDWEEK. INITIAL CONCERN WILL BE NEXT ROUND OF MODERATE TO
HEAVY LK EFFECT SNOWS THAT KICK OFF ON SUNDAY. NW FLOW AREAS IN LINE
TO SEE THE MOST SNOW. IN THE WEST...SHORTER OVER-WATER FETCH RESULTS
IN LOWER INVERSION HEIGHTS AROUND 5KFT AND LESS LAKE INDUCED CAPE.
TEMPS MAINLY BLO -20C IN THE LK EFFECT CONVECTIVE LAYER POINT TO NOT
AS MUCH FOR SNOW ACCUMULATION BUT GIVEN SMALL SNOWFLAKE SIZE THE
VSBY WILL BE POOR IN ANY SNOW SHOWERS. AS MENTIONED IN SHORT TERM
DISCUSSION...BLSN/DRSN MAY NOW BE MORE OF ISSUE ALONG SHORE DUE TO
THE ICE BUILDUP IN LAST FEW DAYS. BTWN THE VSBY ISSUES AND MODERATE
SNOW...WILL CARRY LK EFFECT SNOW ADVY THROUGH DAYBREAK ON MONDAY.
HEAVIER SNOW EXPECTED OVER THE EAST...ESPECIALLY FROM MUNISING EAST
ACROSS THE FAVORED SNOWBELTS NORTH OF M-28 TO THE NORTH OF NEWBERRY.
UNLIKE THE WEST...MUCH LONGER OVER-WATER FETCH RESULTS IN INVERSION
HEIGHTS TO 8KFT AND LAKE INDUCED CAPES NEAR 700J/KG. ALSO UNLIKE THE
WEST...MORE OF THE DGZ IS WITHIN THE LAKE EFFECT LAYER...LEADING TO
HIGHER SLR/S OVER 25:1. KEY FOR THE HEAVY SNOW WILL BE WHERE
STRONGEST CONVERGENCE SETS UP SUNDAY NIGHT THROUGH MONDAY MORNING.
UNFORTUNATELY STILL SOME DESCREPANCY HERE...WITH REGIONAL-GEM AND
GFS OVER LUCE COUNTY WHILE NAM AND NCEP WRF-ARW ALONG WITH LOCAL WRF
ARE FARTHER WEST MORE INTO ALGER COUNTY. NOTICED THAT NAM SFC
CONVERGENCE IS FARTHER WEST COMPARED TO H95 CONVERGENCE. SFC
CONVERGENCE PEGGED WESTERN EDGE OF LK EFFECT TODAY FAIRLY WELL...SO
FOLLOWED THAT IDEA FOR POPS. KEPT HIGHER SNOW IN THE SNOWBELTS OF
EASTERN ALGER COUNTY THROUGH NORTHERN LUCE COUNTY. FOR THOSE AREAS
SNOW AMOUNTS OF 5-7 INCHES ARE EXPECTED SUNDAY NIGHT WITH ADDITIONAL
3-6 INCHES ON MONDAY. CERTAINLY POSSIBLE THAT MODERATE SNOW AMOUNTS
MAY FALL AS FAR WEST AS AU TRAIN/MUNISING AS WELL...ESPECIALLY IF
THE FARTHER WEST CONVERGENCE CAMP OF MODELS IS CORRECT. LK EFFECT
SNOW WARNING STARTS UP ON SUNDAY AND WILL JUST RUN IT ALL THE WAY
THROUGH MONDAY AS BLYR WINDS DO NOT REALLY BACK MORE WNW UNTIL LATER
MONDAY AFTN. LINGERED HIGHER POPS FOR SNOW SHOWERS EAST OF MUNISING
ON MONDAY NIGHT...BUT INVERSIONS LOWERING BLO 5KFT SHOULD BEGIN TO
TAKE TOLL ON INTENSITY OF LK EFFECT.
AWAY FROM THE LK EFFECT COLD WILL BE MAIN STORY. LGT WINDS AND DRY
AIRMASS LEADS TO POTENTIAL FOR MIN TEMPS WELL BLO ZERO SUNDAY NIGHT.
MAX TEMPS MONDAY LIKELY ONLY STRUGGLE INTO LOWER TEENS ABOVE ZERO.
ONCE THE LK EFFECT SUBSIDES LATER MONDAY NIGHT...ATTN IS ON
APPROACHING CLIPPER SHORTWAVE/PV ANAMOLY DIVING IN FROM NORTHERN
PLAINS. NAM APPEARS FARTHER NORTH WITH TRACK OF WAVE...RESULTING IN
STRONGER MOISTURE TRANSPORT/WARM AIR ADVECTION INTO NORTHERN WI/UPR
MICHIGAN. GFS/GEM-NH/ECMWF FARTHER SOUTH WITH ALL THE FORCING AND
ONLY GLANCE UPR MICHIGAN WITH SYSTEM SNOW. SEEMS THAT SHORTWAVE
WOULD TEND TO DIG FARTHER SOUTH GIVEN DOWNSTREAM TROUGHING OVER THE
EASTERN CONUS. MODELS HAVE BASICALLY BEEN CONSISTENT IN KEEPING
SYSTEM TO THE SOUTH AND THOUGH 12Z GFS DID JOG NORTH SOME...THE 12Z
ECMWF IS KEEPING TRACK TO THE SOUTH. EVEN WITH A DIRECT HIT FROM
SYSTEM...LACK OF AVAILABLE MOISTURE WITH PWATS JUST SHY OF NORMAL
AND H7 MIXING RATIOS NOT EVEN 2G/KG...WOULD KEEP SNOW AMOUNTS TO AN
INCH OR TWO. BIGGER IMPACT IS DOWNSTREAM OF LK MICHIGAN IN EASTERN
CWA...WHERE OVER-WATER INSTABILITY WOULD BE PRESENT WITH H85 TEMPS
BLO -10C COMBINING WITH THE LARGER SCALE LIFT FROM SYSTEM MAYBE
COULD HELP GENERATE ADVY LEVEL SNOWS.
NEXT CLIPPER MOVING THROUGH WEDNESDAY NIGHT INTO THURSDAY SEEMS TO
HAVE BETTER SHOT AT IMPACTING MUCH OF UPR MICHIGAN WITH SNOW. THOUGH
SFC LOW TRACKS WELL TO SOUTH ACROSS IA AND SOUTHERN WI...H85 TROUGH
IS FARTHER NORTH AND ALLOWS TEMP/MOISTURE ADVECTION INTO UPR
MICHIGAN. TEND TO THINK HEAVIER QPF WILL END UP SOUTH OF CWA THOUGH
AS RIGHT ENTRANCE REGION OF JET PLACES BETTER UPR DIVERGENCE SOUTH
OF UPR MICHIGAN. EVEN SO...WIDESPREAD SNOW OF 1-3"/2-4" COULD OCCUR
ACROSS CWA INTO THURSDAY. MAYBE SOME LK EFFECT ON THE BACKSIDE OF
THE TROUGH BUT TEMPS ARE MODERATING BY THIS TIME AS H85 TEMPS ARE
ONLY DOWN TO AROUND -13C. CONTINUING MODERATION ON FRIDAY AND
SATURDAY RESULTING IN LK EFFECT TO SHUT DOWN AND HIGH TEMPS BOTH
FRIDAY AND SATURDAY POSSIBLY EXCEEDING 30 DEGREES. NEXT TROUGH AND
SNOW CHANCES ARRIVES LATER IN THE WEEKEND.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SUNDAY AFTERNOON)
ISSUED AT 1221 PM EST SAT FEB 2 2013
CMX...EXPECT IFR/MVFR CONDITIONS IN -SHSN THRU THIS AFTN TO GIVE WAY
TO VFR CONDITIONS WITH WSHFT TO THE SW THIS EVNG. AS ANOTHER UPR
DISTURBANCE/SFC TROF APRCH OVERNGT...MORE -SN/MVFR CONDITIONS WL
PREDOMINATE AFT 06Z. AS THE TROF PASSES TOWARD 12Z...EXPECT A PERIOD
OF HEAVIER SHSN WITH LIFR CONDITIONS FOR AT LEAST A COUPLE OF HRS.
FOLLOWING THE PASSAGE OF THE TROF/HEAVIER SHSN...IFR CONDITIONS WL
THEN LINGER THE REST OF THE TAF PERIOD WITH LES/SMALL SN FLAKES/SOME
BLSN EFFECTIVELY REDUCING VSBY.
IWD...VFR CONDITIONS THRU THIS EVNG WL GIVE WAY TO SOME -SN/MVFR
CONDITIONS LATE TNGT WITH APRCH OF DISTURBANCE/LO PRES TROF. IFR
CONDITIONS WL THEN ACCOMPANY THE PASSAGE OF THE TROF AND THEN
PERSIST AS LES SETS UP IN THE WAKE OF THE PASSAGE WITH WSHFT TO NW.
SAW...EXPECT VFR CONDITIONS TO PREDOMINATE THRU TNGT WITH DOWNSLOPE
NW FLOW BACKING TO THE WSW AHEAD OF APRCHG LO PRES TROF. SOME MVFR
CIGS MAY IMPACT THIS SITE FOLLOWING THE PASSAGE OF THE TROF ON SUN
MRNG AS VERY COLD AIR SURGES BACK INTO THE AREA.
&&
.MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 423 PM EST SAT FEB 2 2013
WSW WINDS UP TO 25 KTS WILL VEER NW LATE TONIGHT/SUN MORNING IN THE
WAKE OF A LO PRES TROF PASSAGE. AS ANOTHER VERY COLD AIRMASS POURS
OVER THE LAKE AND NW WINDS INCREASE UP TO 30 KTS...EXPECT HEAVY
FREEZING SPRAY TO DEVELOP OVER THE W AND CENTRAL ON SUN AND TO
CONTINUE OVER MUCH OF THE LAKE THROUGH MONDAY. WINDS DIMINISH BLO 25
KTS BY TUESDAY. EXPECT A COUPLE OF CLIPPER SYSTEMS TO MOVE ACROSS THE
UPPER GREAT LAKES THE REST OF THE WEEK...BUT WINDS SHOULD STAY MAINLY
BLO 30 KTS. GRADUALLY WARMING TEMPERATURES WILL END THE POTENTIAL FOR
FREEZING SPRAY.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
LAKE EFFECT SNOW ADVISORY FROM 4 AM SUNDAY TO 7 AM EST MONDAY
FOR MIZ001>003-084.
LAKE EFFECT SNOW WARNING FROM 10 AM SUNDAY TO 7 PM EST MONDAY
FOR MIZ006-007-085.
LAKE SUPERIOR...
HEAVY FREEZING SPRAY WATCH FROM SUNDAY EVENING THROUGH MONDAY
MORNING FOR LSZ249>251-266-267.
HEAVY FREEZING SPRAY WARNING FROM 1 PM SUNDAY TO 7 AM EST MONDAY
FOR LSZ248-265.
HEAVY FREEZING SPRAY WARNING FROM 1 AM SUNDAY TO 7 AM EST MONDAY
FOR LSZ244-245-264.
HEAVY FREEZING SPRAY WARNING FROM 1 AM EST /MIDNIGHT CST/ SUNDAY
TO 1 AM EST /MIDNIGHT CST/ MONDAY FOR LSZ241>243-263.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...KC
LONG TERM...JLA
AVIATION...KC
MARINE...KC/JLA
AREA FORECAST DISCUSSION
NWS HASTINGS NE
1120 PM CST FRI FEB 1 2013
.AVIATION...06Z TAF. SATELLITE AND OBSERVATIONS SHOW SOME LOWER
CLOUDS THAT WILL AFFECT THE KGRI TERMINAL AREA. THESE SHOULD BE
VFR AND SHOULD DIMINISH AFTER DAY BREAK. A SURFACE TROUGH THAT IS
MOVING THROUGH THE AREA AT THIS TIME HAS TURNED WINDS TO THE
NORTHWEST. THEY WILL INCREASE A BIT AROUND SUNRISE...THEN BECOME
GUSTY AND INCREASE THIS AFTERNOON.
&&
.PREV DISCUSSION... /ISSUED 656 PM CST FRI FEB 1 2013/
UPDATE...EVENING UPPER AIR ANALYSIS INDICATES LONGWAVE TROUGHING
OVER THE EASTERN TWO-THIRDS OF THE CONUS...WITH RIDGING BUILDING
INTO THE WEST. MID AND UPPER LEVEL FLOW REMAINS FROM THE NORTHWEST
ACROSS THE CENTRAL PLAINS...MAXING OUT AT AROUND 70KTS NEAR 200MB
OVER OUR AREA. WATER VAPOR IMAGERY INDICATES A SUBTLE MID LEVEL
SHORT WAVE EXTENDING FROM THE DAKOTAS...SOUTHWEST INTO WESTERN
NEBRASKA AND SOUTHEASTERN WYOMING. AT THE SURFACE A WEAK AREA OF
BAROMETRIC PRESSURE EXISTS OVER EASTERN SOUTH DAKOTA...WITH A
TROUGH EXTENDING SOUTHWEST FROM THE LOW ACROSS PORTIONS OF
NEBRASKA AND KANSAS. THIS TROUGH PRETTY MUCH BISECTS OUR
CWA...WITH THE LOW LEVEL WIND FIELD ACROSS THE SOUTHEASTERN HALF
OF OUR CWA REMAINING FROM THE SOUTHWEST...AND LOCATIONS FARTHER
NORTHWEST NOW OBSERVING A SURFACE WIND FROM THE NORTHWEST. RADAR
DATA FROM KUEX...KLNX...AND KGLD ALL INDICATE LIGHT ELEVATED
PRECIPITATION EXTENDING FROM PORTIONS OF WESTERN NEBRASKA INTO
NORTHWESTERN KANSAS AND NORTHEASTERN COLORADO. REPORTS OF
PRECIPITATION ACTUALLY BEING REALIZED AT THE SURFACE HAVE BEEN FEW
AND FAR IN BETWEEN HOWEVER...WITH PROXIMITY SOUNDINGS FROM LAPS
AND RAP ANALYSIS INDICATING A VERY DRY LOWER TROPOSPHERE IS LIKELY
PREVENTING MUCH OF ANY PRECIPITATION FROM MAKING IT TO THE
SURFACE.
GUIDANCE FROM THE NAM...OPERATIONAL GFS...EC...SREF-MEAN...AND RAP
ALL SUGGEST THE MID LEVEL SHORT WAVE...CURRENTLY OVER THE NORTHERN
AND CENTRAL PLAINS...WILL CONTINUE MOVING SOUTHEAST TONIGHT...WITH
THE MID LEVEL TROUGH AXIS EXPECTED TO CLEAR OUR CWA SHORTLY AFTER
06Z. VERY WEAK MID LEVEL THERMAL ADVECTION AHEAD OF THE TROUGH
AXIS IS CREATING JUST ENOUGH OMEGA FOR THE ELEVATED PRECIPITATION
CURRENTLY BEING INDICATED BY AREA RADARS...WITH THIS AXIS OF WEAK
OMEGA EXPECTED TO CONTINUE PUSHING ACROSS OUR AREA TONIGHT AS THE
MID LEVEL TROUGH AXIS DOES THE SAME. THE BACK EDGE OF THIS OMEGA
AXIS IS APPARENTLY ALREADY WORKING INTO NORTHERN AND WESTERN
NEBRASKA...WITH KLNX INDICATING THE BACK EDGE ELEVATED
PRECIPITATION EXTENDING FROM NEAR KANW TO NEAR KIBM. GIVEN THE
CURRENT MOVEMENT OF THE MID LEVEL SHORT WAVE ON WATER VAPOR
IMAGERY...AND RADAR TRENDS THROUGH THE PAST 2-3 HOURS...IT APPEARS
THE BEST CHANCE FOR PRECIPITATION OVER OUR AREA WILL OCCUR BETWEEN
NOW AND 06Z...WITH DRY CONDITIONS LIKELY THEREAFTER AS THE MID
LEVEL TROUGH AXIS CLEARS THE AREA AND SUBSIDENCE SETTLES IN.
DESPITE THE RETURNS AS INDICATED BY AREA RADARS...ITS HARD TO
IGNORE THE VERY DRY LOWER TROPOSPHERE CURRENTLY IN PLACE AND THUS
IS SEEMS UNLIKELY MEASURABLE PRECIPITATION WILL BE REALIZED ACROSS
ANY OF OUR CWA TONIGHT. GIVEN THIS...WENT AHEAD AND PULLED POPS
FROM THE FORECAST FOR TONIGHT. THAT BEING SAID...CANNOT COMPLETELY
RULE OUT AN OCCASIONAL SPRINKLE MAKING IT TO THE SURFACE THROUGH
THE NEXT FEW HOURS AS THERE HAVE BEEN A FEW OBSERVATIONS ACROSS
WESTERN NEBRASKA WHICH INDICATED A BRIEF PERIOD OF PRECIPITATION
HERE OR THERE. GIVEN THE AFOREMENTIONED RADAR RETURNS AND
OBSERVATIONS...OPTED TO GO WITH A MENTION OF SPRINKLES ACROSS OR
SOUTHWESTERN CWA THROUGH THIS EVENING AS THE MOST ENHANCED AREA OF
RADAR RETURNS...AROUND 25DBZ...PUSH OVER THOSE AREAS.
PROXIMITY SOUNDINGS FROM ACROSS OUR CWA PER LAPS AND RAP ANALYSIS
INDICATE AN ELEVATED WARM LAYER DOES EXIST NEAR 850MB...WITH
FORECAST PROXIMITY SOUNDINGS PER THE NAM...OPERATIONAL GFS...AND
RAP SUGGESTING THIS ELEVATED WARM LAYER WILL REMAIN INTACT THROUGH
MUCH OF THE NIGHT. IF MORE SIGNIFICANT PRECIPITATION WERE EXPECTED
TO MAKE IT TO THE SURFACE...THIS WOULD CERTAINLY CREATE CONCERNS
WITH RESPECT TO FREEZING RAIN. THAT BEING SAID...BECAUSE THE RADAR
RETURNS THUS FAR THIS EVENING HAVE BEEN SO WEAK...AND BECAUSE THE
MAJORITY GUIDANCE SUGGESTS NO PRECIPITATION WILL BE REALIZED OVER
OUR AREA TONIGHT...AND BECAUSE THERE IS SUCH A DEEP LAYER OF LOWER
TROPOSPHERIC DRY AIR IN PLACE...AM NOT OVERLY CONCERNED WITH AN
ICING THREAT AT THIS TIME. SHOULD SPRINKLES BE REALIZED ACROSS
PORTIONS OF THE CWA AFTER 02Z TONIGHT...THEN TECHNICALLY THESE
WOULD BE FREEZING SPRINKLES AS SURFACE TEMPERATURES WILL HAVE
DROPPED BELOW FREEZING BY THEN. BUT AT THIS TIME THE THREAT OF
ICING FROM SUCH ACTIVITY IS LITTLE TO NONE AND GIVEN THIS...OPTED
TO PULL ANY MENTION OF FREEING RAIN FROM THE HWO.
REMAINDER OF THE FORECAST REMAINS IN GOOD SHAPE...WITH ONLY SOME
MINOR TWEAKS MADE TO HOURLY TEMPERATURE...SKY...WIND...AND
DEWPOINT GRIDS TO ACCOUNT FOR CURRENT OBSERVATIONS.
PREV DISCUSSION... /ISSUED 324 PM CST FRI FEB 1 2013/
A TROF EMBEDDED IN NW FLOW MAY DELIVER A LIGHT WINTRY MIX IN
SPOTS TNGT THEN WE DEAL WITH WINDY CONDITIONS N OF I-80 SAT...
SHORT TERM...TONIGHT AND SATURDAY
UPPER-LEVELS: A +PNA PATTERN WAS IN PLACE...WITH A WRN N AMERICA
RIDGE AND AN ERN TROF. A PAIR OF PV ANOMALIES WERE DIVING DOWN THE
BACK SIDE OF THE LGWV TROF. THE 1ST WAS OVER WY AT MID AFTN WITH THE
2ND OVER ALBERTA HEADING FOR MT. THE FIRST SHRTWV TROF WILL SLIDE
INTO AND THRU KS TNGT. THE SECOND WILL FOLLOW IT INTO NEB AFTER
MIDNGT. A SHRTWV RIDGE FOLLOWS SAT MRNG...WITH A THIRD PV ANOMALY
MISSING AND HEADING INTO IA...AS THE LGWV PATTERN PROGRESSES A BIT
AND HGTS RISE.
STRONG MO HIGH PRES WILL DEPART TO THE MID-ATLC STATES TNGT. THE
ARCTIC FRONT BISECTED NEB-KS. THIS FRONT AND ITS THERMAL RIBBON WERE
BEING SHOVED E BY SW FLOW AHEAD OF A VERY WEAK SFC LOW. THIS LOW
TRACKS JUST N OF THE FCST AREA...TO THE MS RIVER BY DAYBREAK SAT.
HIGH PRES FOLLOWS HERE TOMORROW.
TNGT: VARIABLE CLOUDS BUT OVERALL EXPECT SKIES TO AVERAGE M/CLOUDY.
EXPANDED THREAT OF VERY LIGHT PCPN TO THE ENTIRE FCST AREA AND WE
NOW HAVE CHANCE POPS FOR AREAS NE OF THE TRI-CITIES AND FROM HWY
136 DOWN INTO N-CNTRL KS. ODDS ARE MOST PLACES REMAIN DRY WITH
LACK OF MSTR IN THE SUB-CLOUD LAYER...BUT WAS NOT COMFORTABLE WITH
AN ENTIRELY DRY FCST.
NEXT ISSUE IS PCPN TYPE. BOTH DDC/LBF HAD A WARM NOSE IN 12Z
SOUNDINGS. NAM/GFS BUFKIT SOUNDINGS SUGGEST 850 MB HAS WARMED TO
+3C OVERHEAD THIS AFTN. SO "IF" PCPN FALLS TNGT...PLAYED IT AS
FLURRIES OR A BRIEF SNOW SHWR NE OF THE TRI-CITIES...FLURRIES OR
SPRINKLES IN THE TRI-CITIES...AND SPRINKLES AND POSSIBLY A RAIN
SHWR S OF HWY 6 INTO N-CNTRL KS. THAT SAID...BELOIT IS STILL SUB-
FRZG AND THE REST OF N-CNTRL KS NOT MUCH ABOVE FRZG. IF TEMPS
COOL BACK DOWN BELOW FRZG AND A FEW -SHRA OCCUR...THERE COULD BE A
TOUCH OF GLAZE. THE LOW PROBABILITY THREAT IS NOW OUTLOOKED IN THE
HWO.
BEST CHANCE OF PCPN WILL OCCUR 9PM-3AM.
USED BURST OF PW AND K-INDEX TO ASSIST IN TIMING/LOCATION OF POPS
THRU THE FCST AREA. CHANCE POPS S OF HWY 136 WERE BASED ON HI-RES
MODEL REFLECTIVITY WHICH IS SUPPORTED BY THE TRACK OF THE PV
ANOMALY.
TEMPS: VARIABLE CLOUD COVER LOWERS CONFIDENCE SOMEWHAT...BUT
OVERALL THINK IT WILL BE A MILD NGT. TEMPS ARE BIAS CORRECTED
BLEND OF 2M TEMPS AND THE PREVIOUS GID FCST /21-27F/.
SAT: SKIES SHOULD BE P/CLOUDY S AND W OF THE TRI-CITIES AT DAWN...
AND M/CLOUDY N AND E. CLEARING AS THE DAY PROGRESSES AND WINDY N OF
I-80 IN THE "WARM" SECTOR OF THE NEXT PV ANOMALY AND CLIPPER FCST
OVER IA.
WIND: THERE IS A LOW PROBABILITY WE MAY NEED A WIND ADVISORY FOR
SOME OF OUR COUNTIES N OF I-80. SUBJECTIVE PROBABILITY PUTS IT
AROUND 40 PERCENT. WITH THE STRENGTH OF THE LOW-LEVEL WIND
FIELDS...BUFKIT MIXING HGTS ARE UNNERVING FROM BOTH THE NAM/GFS.
FOR NOW WE/VE INCLUDED G40 MPH IN THE FCST. THE MAIN CORE OF THE
STRONGEST WIND MOVES IN AFTER 21Z. THE 15Z SREF MEAN INCREASES
SPEEDS 40-45 KTS 21Z-00Z. THIS COINCIDES WITH PEAK HEATING AND
WILL NEED TO BE CONSIDERED BY THE MID SHIFT.
TEMPS ARE BIAS CORRECTED MOS GUIDE WITH SOME ADDITIONAL LOWERING
OF TEMPS OVER THE SNOW COVER S AND E OF HASTINGS AND SOME RAISING
FROM LXN DOWN TO THE KS BORDER...WHERE BIAS CORRECTION PROBABLY
CUT TEMPS TOO MUCH.
LONG TERM...SATURDAY NIGHT THROUGH FRIDAY. BEGINNING SATURDAY
NIGHT...A NORTHWEST FLOW PATTERN WILL BE IN PLACE ACROSS THE CENTRAL
PLAINS AND SHORTWAVE ENERGY IS PROGGED TO TRANSLATE SOUTHEAST ALONG
THE MISSOURI RIVER. COLD AIR BACKS IN BRIEFLY FOR THE OVERNIGHT
TIME FRAME...THEN IN RETURN FLOW ON SUNDAY THE AIRMASS MODERATES
BEHIND THE DEPARTING WAVE. THE NORTHWEST FLOW PATTERN REMAINS
PROGRESSIVE THROUGH MID WEEK WEEK WITH A SERIES OF WAVES TRANSLATING
THRU FLOW...MAINLY ALONG AND EAST OF THE MISSOURI RIVER...WHICH WILL
BRING A FEW COLD FRONTS ACROSS THE PLAINS WITH THE BRUNT OF THE
COOLER AIR REMAINING TO OUR EAST. IN THIS REGIME WE WILL SEE
ALTERNATING PERIODS OF WAA/CAA BUT WITH CONDITIONS REMAINING DRY.
AROUND MID WEEK...THE RIDGING OVER THE ROCKIES BREAKS DOWN AND
SETTLES ONTO THE PLAINS ALLOWING FOR A PROGRESSIVE BUT MORE ZONAL
FLOW PATTERN. EXTENDED MODELS ARE FAIRLY CONSISTENT WITH YET
ANOTHER SHORTWAVE TROUGH TO CROSS THE NORTHERN AND CENTRAL PLAINS
WEDNESDAY NIGHT...AND MODELS ARE HINTING THAT FRONT MAY BECOME
ACTIVE WEDNESDAY NIGHT NEAR OUR SOUTHEAST ZONES. CONFIDENCE IN PCPN
THIS FAR OUT IS NOT HIGH AND WILL CONTINUE TO MONITOR. ONCE THIS
WAVE DEPARTS...AN UPPER RIDGE SETTLES ACROSS THE INTERIOR CONUS
WHILE AN UPSTREAM TROUGH MOVES INTO THE ROCKIES. THE WEATHER
PATTERN LOOKS TO BECOME MORE ACTIVE NEXT WEEKEND WITH THE
PROGRESSION OF THE WESTERN TROUGH AND THIS WILL BE SOMETHING TO KEEP
AN EYE ON. UNTIL THAT TIME FRAME HOWEVER...LOOK FOR MAINLY DRY
CONDITIONS WITH TEMPS ABOVE NORMAL FOR THE MOST PART...ESPECIALLY
AFTER THE SNOW MELTS IN OUR EASTERN ZONES.
&&
.GID WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
KS...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS GRAND FORKS ND
317 PM CST SAT FEB 2 2013
.SHORT TERM...
MAIN ISSUE WILL BE SNOW AND BLOWING SNOW LATE THIS AFTERNOON AND
EVENING.
SAT LOOP AND 500MB ANALYSIS SHOW THE CLIPPER SHORTWAVE MOVING
THROUGH CENTRAL ND...WITH A FAIR AMOUNT OF SNOW ACROSS MUCH OF THE
VALLEY. BEST RADAR RETURNS HAVE BEEN FROM VALLEY CITY TOWARDS
FARGO...AND WEBCAMS SHOW SOME LIGHT ACCUMULATIONS. A FEW OBS SITES
THIS MORNING WENT DOWN TO 1/4SM VIS BRIEFLY AS HEAVIER SNOW BANDS
MOVED OVER THEM...BUT QUICKLY IMPROVED WHEN SNOW BECAME LESS
INTENSE. OF GREATER IMPACT TO THE PUBLIC WILL BE THE WINDS ON THE
BACKSIDE OF THE SFC LOW CURRENTLY NEAR THE JAMESTOWN AREA. WINDS
HAVE SHIFTED TO THE NORTHWEST BEHIND THE LOW AND MANY HAVE
INCREASED INTO THE 25 TO 35 KT RANGE. THERE HAS BEEN QUITE A BIT
OF BLOWING SNOW AND NEAR ZERO VISIBILITIES IN THE WESTERN PART OF
THE STATE.
TRAJECTORY OF THE SFC LOW AND THE HIGH MSLP FALL/RISE
COUPLET WOULD HAVE THE HIGHEST WINDS MAINLY IMPACTING OUR WESTERN
AND SOUTHERN COUNTIES. RAP HAS HAD A DECENT HANDLE ON THE SFC
WINDS IN THE WEST SO HAVE FOLLOWED IT FAIRLY CLOSELY. MODEL
SOUNDINGS SHOW THE BEST CHANCES FOR GOOD MIXING TO THE SFC WILL BE
MAINLY OVER THE FAR SOUTHWEST COUNTIES. WINDS HAVE ALREADY SHIFTED
TO THE WEST IN WESTERN BENSON COUNTY AND SHOULD START BLOWING IN
THE NEXT HOUR OR TWO. RADAR ESTIMATES SHOW A COUPLE OF INCHES OF
FRESH ACCUMULATION FROM KDVL DOWN TOWARDS THE SOUTHERN VALLEY.
WITH FRESH SNOW...BLOWING SNOW AND REDUCED VIS WILL BE A PROBLEM.
WITH THE WORST OF THE SFC WINDS JUST MOVING BY TO OUR SOUTH AND
WEST...FOR NOW JUST INCLUDED THE HIGHER TERRAIN OF THE DEVILS LAKE
DOWN TO RANSOM/SARGENT COUNTIES...ALONG WITH RICHLAND AND WILKEN
COUNTIES. WILL HAVE TO WATCH FAR WESTERN CASS COUNTY FOR BLOWING
SNOW BUT FOR NOW WILL LEAVE FARGO OUT OF IT AS IT SEEMS THAT THE
WORST WINDS WILL MISS THEM. WINDS SHOULD START TO COME DOWN BY MID
EVENING IN THE DEVILS LAKE BASIN AND AROUND 06Z FURTHER SOUTH.
THE SHORTWAVE WILL MOVE QUICKLY OFF TO THE EAST TONIGHT...WITH
WINDS TAPERING OFF AND A WEAK SFC HIGH MOVING IN BY MORNING.
DEPENDING ON THE AMOUNT OF CLEARING BY MORNING...THERE COULD AGAIN
BE TEMPERATURES IN THE TEENS BELOW ZERO AND WIND CHILL VALUES
APPROACHING ADVISORY CRITERIA IN THE NORTH BY THE EARLY MORNING
HOURS. HOWEVER...WITH THE ONGOING WSW FOR BLOWING SNOW AND THE
UNCERTAINTY OF CLOUDS WILL LEAVE OUT FOR NOW.
ANOTHER WEAK SHORTWAVE WILL BEGIN TO DIG INTO THE WESTERN DAKOTAS
SUNDAY...WITH ANOTHER WEAK SFC LOW DEVELOPING TO THE SOUTHWEST OF
THE CWA. MODELS HAVE BEEN TRENDING FURTHER SOUTH AND WEST SO KEPT
HIGHEST POPS FROM THE DEVILS LAKE BASIN TOWARDS THE LAKES COUNTRY FOR
SUNDAY INTO SUNDAY NIGHT. TIGHT TEMP GRADIENT REMAINS OVER THE
NORTHERN PLAINS BUT THINK THAT ARCTIC AIR WILL REMAIN IN PLACE
OVER MOST OF THE REGION SO KEPT HIGHS MAINLY IN THE SINGLE DIGITS
WITH SOME TEENS IN THE WEST. THERE SHOULD BE A REINFORCING SURGE
OF COLD AIR SUNDAY NIGHT WHICH WILL HELP KEEP LOWS MOSTLY BELOW
ZERO.
ANOTHER WEAK CLIPPER SYSTEM WILL BEGIN TO MOVE INTO SOUTHERN
CANADA BY MONDAY...BRINGING ANOTHER ROUND OF PRECIP INTO OUR
NORTHWESTERN CWA BY MONDAY AFTERNOON. TEMPS SHOULD REMAIN BELOW
AVERAGE. THE PARADE OF WEAK SHORTWAVES WILL CONTINUE INTO MONDAY
NIGHT AND TUESDAY. THERE ARE SOME DIFFERENCES IN THE TRACK OF THE
MONDAY NIGHT/TUESDAY LOW...BUT OVERALL THIS SYSTEM SEEMS A BIT
FURTHER NORTH AND EAST THAN THE PREVIOUS FEW SYSTEMS. STILL PRETTY
UNCERTAIN SO INCLUDED JUST HIGH CHANCE POPS FOR NOW BUT WILL
PROBABLY NEED TO BUMP UP. THERE SHOULD BE A DECENT AMOUNT OF WARM
AIR ADVECTION AND SOME WARMER AIR GETTING INTO AT LEAST THE
SOUTHWESTERN CWA. STARTED BRINGING LOWS IN THE TEENS INTO THE WEST
MONDAY NIGHT AND HIGHS UP INTO THE TEENS TO 20S FOR TUESDAY.
.LONG TERM (TUE NIGHT-SAT)...
NORTHWEST FLOW ALOFT WILL GRADUALLY TRANSITION MORE TO A ZONAL FLOW
AND THEN BY LATE IN THE PERIOD...BRIEF RIDGING FOLLOWED BY SOUTHWEST
FLOW. MODELS SEEM PRETTY CONSISTENT IN DEPICTING ANOTHER SHOT OF
LIGHT SNOW MAINLY ACROSS THE NORTHERN FA ON WED/WED NIGHT. THURSDAY
AND FRIDAY SHOULD BE QUIET WITH MILDER AIR MOVING BACK INTO THE
AREA. STILL LOOKING TO TURN A LITTLE MORE ACTIVE AGAIN BY SATURDAY
IN THE SOUTHWEST FLOW WITH A COLORADO LOW TAKING SHAPE. AT THIS
POINT THIS SYSTEM WOULD AFFECT THE SOUTHERN FA MORE THAN THE NORTH
BUT IT IS A LONG WAYS OFF YET. WILL HAVE TO SEE WHAT FUTURE MODEL
RUNS HAVE IN STORE FOR THIS SYSTEM.
&&
.AVIATION...
THE BAND OF LIGHT SNOW LOOKS LIKE IT WILL MOVE THROUGH THE AREA
QUICKLY THIS AFTERNOON ONLY BRINGING AN HOUR OR SO OF LOWER VSBYS
BEFORE SHIFTING OFF TO THE SOUTHEAST. THE MAIN QUESTION FOR THE TAFS
IS WHETHER THE GUSTY WINDS WHICH ARE CURRENTLY WEST OF THE FA MAKE
IT INTO THE RED RIVER VALLEY TONIGHT AND CAUSE ANY REDUCTION TO VBSY
DUE TO BLOWING SNOW. BROUGHT WINDS UP AND INSERTED SOME BLOWING SNOW
WITH THE WORST CONDITIONS AT KFAR. WINDS SHOULD DIE DOWN LATER IN
THE EVENING.
&&
.FGF WATCHES/WARNINGS/ADVISORIES...
ND...WINTER WEATHER ADVISORY UNTIL 9 PM CST THIS EVENING FOR NDZ006-
007-014-015-024-026-028-054.
WINTER WEATHER ADVISORY UNTIL MIDNIGHT CST TONIGHT FOR NDZ038-
049-052-053.
MN...WINTER WEATHER ADVISORY UNTIL MIDNIGHT CST TONIGHT FOR MNZ029.
&&
$$
JR/GODON
AREA FORECAST DISCUSSION
NWS GRAND FORKS ND
1006 AM CST SAT FEB 2 2013
.DISCUSSION...
MADE SOME MINOR TWEAKS TO POPS/WX FOR SNOW AS THE CLIPPER SYSTEM
MOVES THROUGH THE AREA. OBS SHOW SOME -SN HAS STARTED IN THE
SOUTHWESTERN CWA...ALTHOUGH NOTHING ACCUMULATING SO FAR. NAM AND
RAP SHOW THE BEST PRECIP CHANCES WILL BE WITH THE MAIN SHORTWAVE
COMING THROUGH THIS AFTERNOON...WITH THE BEST CHANCES FOR
1 TO 2 INCHES OF SNOW STRETCHING SOUTHEASTWARD FROM NORTH CENTRAL
ND TOWARDS LAKES COUNTRY. MOST OF THE HIGHER WINDS THIS AFTERNOON
WILL BE TO OUR WEST...BUT THE FAR WESTERN TIER OF COUNTIES COULD
GET FAIRLY BREEZY LATE THIS AFTERNOON AND EVENING BEHIND THE SFC
LOW. INCLUDED A PATCHY BLOWING SNOW MENTION FOR A FEW HOURS...NO
HEADLINES BUT WILL KEEP AN EYE ON THINGS. ADJUSTED TEMPS A BIT AS
READINGS HAVE BEEN A BIT SLOW TO WARM IN THE BITTERLY COLD
NORTHEASTERN COUNTIES...BUT KEPT HIGHS IN THE SINGLE DIGITS TO
NEAR 20 IN THE FAR SOUTHWEST.
&&
.AVIATION...
VFR/MVFR CEILINGS WILL INCREASE FROM WEST TO EAST THROUGH THE DAY AS
A LOW PRESSURE SYSTEM MOVES ACROSS THE REGION. SOME LIGHT SNOW IS
POSSIBLE FOR AIRFIELDS ALONG AND WEST OF THE VALLEY AFTER 15 UTC.
SNOW SHOULD BE LIGHT...BUT SOME REDUCTIONS IN VISIBILITY LESS THAN
ONE MILE ARE POSSIBLE. LIGHT SOUTH-SOUTHWEST WIND THROUGH THE DAY
WILL INCREASE AND SHIFT TO THE NORTHWEST THIS EVENING AND
OVERNIGHT.
&&
.PREV DISCUSSION... /ISSUED 400 AM CST SAT FEB 2 2013/
SHORT TERM...TODAY THROUGH MONDAY NIGHT
MAIN FORECAST CHALLENGES INCLUDE LIGHT SNOW CHANCES AND TEMPERATURES.
GFS/NAM/ECMWF/GEM IN GOOD AGREEMENT AND WILL USE A BLENDED SOLUTION
FOR THIS FORECAST PACKAGE.
FOR TODAY...A CLIPPER SYSTEM IN NORTHWEST FLOW ALOFT WILL MOVE ACROSS
THE NORTHERN PLAINS. MOST OF THE FORECAST AREA WILL REMAIN ON THE COOL
SIDE OF THE SYSTEM AS THE SURFACE LOW TRACKS FROM CENTRAL SASKATCHEWAN
TO NORTHEAST SD. AFTERNOON HIGHS WILL MAINLY BE IN THE SINGLE DIGITS
TO LOW TEENS ABOVE ZERO...BUT AREAS WEST OF A LINE FROM DEVILS LAKE
TO VALLEY CITY TO LISBON MAY CLIMB INTO THE LOW 20S. CANADIAN RADARS
SHOW LIGHT SNOW SOUTH AND EAST OF THE SURFACE LOW AND THIS BAND IS
EXPECTED TO MOVE SOUTHEASTWARD THROUGH THE DAY...MAINLY IMPACTING
EASTERN ND INTO WEST CENTRAL MN. SLOWED THE TIMING OF THE HIGHEST
POPS AS LATEST RAP OUTPUT KEEPS MAJORITY OF PRECIPITATION OUT OF
THE FORECAST AREA UNTIL AFTER 15 UTC. TOTAL ACCUMULATIONS THROUGH
TONIGHT WILL GENERALLY BE AN INCH OR LESS.
REMAINING SNOW SHOWERS EXPECTED TO MOVE EAST OF THE FORECAST AREA
BY MIDNIGHT WITH DECREASING CLOUD COVER FROM WEST TO EAST. SUNDAY
MORNING LOWS EXPECTED IN THE 0 TO 10 BELOW RANGE...BUT WILL BE
HIGHLY DEPENDENT ON CLOUD COVER.
ANOTHER WEAK CLIPPER DROPS SOUTH ON SUNDAY...BRINGING A NARROW
BAND OF LIGHT SNOW FROM CENTRAL ND INTO SOUTHWEST MN. STRONG
SURFACE HIGH WILL MOVE INTO THE NORTHERN VALLEY BY 06 UTC MONDAY
AND THIS WILL LIMIT NORTHWARD EXTENT OF PRECIPITATION. MODEL
TRENDS PLACE SNOW FARTHER SOUTH...SO ADJUSTED HIGHEST POPS SOUTH
OF A LINE FROM DEVILS LAKE TO HILLSBORO TO PARK RAPIDS.
ACCUMULATIONS EXPECTED TO BE EVEN LESS THAN TODAY...GENERALLY A
HALF INCH OF LESS. SKIES WILL BE MOSTLY CLOUDY AND TEMPERATURES
WILL BE NEAR OR SLIGHTLY COOLER THAN TODAY IN THE WAKE OF TODAY/S
SYSTEM.
THE PARADE OF CLIPPERS CONTINUE INTO EARLY NEXT WEEK WITH A THIRD
WAVE ON MONDAY. THE TRACK OF THE SURFACE LOW IS A BIT FARTHER
NORTH...SO EXPECT GREATER SPATIAL COVERAGE OF ACCUMULATING
SNOWFALL. STRONG MID-LEVEL WARM AIR ADVECTION WILL COMBINE UPPER
JET DYNAMICS TO PRODUCE A COUPLE INCHES OF SNOW ACROSS THE
NORTHERN VALLEY INTO NORTHWEST MN. WITH TRACK OF THE LOW AND
ALIGNMENT OF THE BAROCLINIC AXIS...TEMPERATURES WILL BE A BIT
WARMER WITH AFTERNOON HIGHS MAINLY IN THE TEENS ABOVE ZERO.
MORNING LOWS WILL CONTINUE TO BE DEPENDENT ON CLOUD COVER...BUT
NOT EXPECTING MUCH DAY TO DAY CHANGE WITH THE COOLEST READINGS
ACROSS THE LAKE OF THE WOODS REGION.
LONG TERM...TUESDAY THROUGH FRIDAY NIGHT
NW FLOW ALOFT WILL SLOWLY TRANSITION TO A MORE ZONAL/SW FLOW ALOFT
BY NEXT WEEKEND. THIS WILL MEAN GRADUALLY WARMING TEMPS ABOVE NORMAL
WITH MINIMAL CHANCES FOR PRECIP THROUGH SAT. THERE IS THE POTENTIAL
FOR SOME LINGERING LIGHT SNOW EARLY TUE IN THE EAST...AND IN THE
NORTH ON WED WITH SOME WAA. OTHERWISE...EXPECT A DRY EXTENDED WITH
A WARMING TREND. THERE ARE SOME HINTS AT A POTENTIAL STORM BY LATE
SAT INTO SUNDAY...WITH THE MAIN POTENTIAL IMPACTS AT THIS TIME
POSSIBLE IN THE SOUTHERN FORECAST AREA.
&&
.FGF WATCHES/WARNINGS/ADVISORIES...
ND...NONE.
MN...NONE.
&&
$$
JR
AREA FORECAST DISCUSSION
NWS BISMARCK ND
422 AM CST SAT FEB 2 2013
.SHORT TERM...TODAY THROUGH SUNDAY...
THE MAIN HIGHLIGHTS OF THE SHORT TERM ARE STRONG WINDS AND LIGHT
ACCUMULATING SNOW THROUGH TONIGHT.
LIGHT SNOW CONTINUES ACROSS CENTRAL NORTH DAKOTA THIS MORNING AS
ANOTHER IMPULSE MOVES OVER THE AREA...WITH A SHARP GRADIENT ALONG
THE EASTERN PERIPHERY OF THE SURFACE ARCTIC HIGH PRESSURE TO THE
EAST. GUIDANCE FROM THE RAP AND 06Z NAM HAVE CAPTURED THIS
SCENARIO WELL THIS MORNING AND THUS HAVE DECIDED TO USE THEM AS A
GUIDE FOR THE CLIPPER SYSTEM THAT IS FORECAST TO MOVE OVER THE AREA
LATER THIS MORNING THROUGH THIS EVENING. THIS CLIPPER SYSTEM WILL
MOVE ALONG AND INTERACT WITH THE BAROCLINIC ZONE...GENERATING
ANOTHER ROUND OF LIGHT SNOW FOR CENTRAL AND EASTERN NORTH DAKOTA.
LIGHT SNOWFALL ACCUMULATIONS ARE EXPECTED AND GENERALLY AROUND AN
INCH NORTH AND EAST OF THE MISSOURI RIVER...WITH UP TO TWO INCHES
POSSIBLE FOR THE JAMES RIVER VALLEY.
LATER THIS MORNING...00Z GFS/NAM BUFR SOUNDINGS DEPICT LAPSE RATES
BECOMING NEARLY ADIABATIC ALLOWING FOR 45 KT H850 WINDS TO
BE MIXED DOWN TO THE SURFACE. COINCIDENT WITH STEEPENING LAPSE
RATES OVER THE AREA...MODEST ISALLOBARIC FORCING OF 6 MB SIX HOUR
PRESSURE RISES WILL MOVE OVER THE AREA. IF DOWNWARD MOMENTUM CAN
BE ACHIEVED...H850 WINDS WILL BE TRANSLATED DOWN TO THE
SURFACE...GENERATING WIDESPREAD GUSTS OF 45 KTS. MODELS ARE IN
GOOD AGREEMENT REGARDING THE OVERALL SEVERITY...BUT THERE IS SOME
DISAGREEMENT REGARDING TIMING. THE ECMWF SEEMS TO BE QUICK TO CUT
OFF THE STRONGEST WINDS BY 00Z...WITH OTHER MODELS HOLDING THE
STRONGEST WINDS THROUGH 03Z OVER THE SOUTHEAST. IN ADDITION TO
STRONG WINDS...AREAS OF BLOWING SNOW ARE POSSIBLE. THE STRONGEST WINDS
WILL NOT COINCIDE WITH THE HEAVIEST SNOWFALL...AND WILL BE FURTHER
HAMPERED BY ABOVE FREEZING TEMPERATURES ACROSS MUCH OF THE AREA.
HOWEVER...AREAS OF BLOWING SNOW AND REDUCED VISIBILITIES WILL BE
POSSIBLE FOR AREAS NORTH AND EAST OF THE MISSOURI RIVER...WHERE
THE HEAVIEST SNOWFALL TOTALS AND SUBFREEZING TEMPERATURES WILL BE
SEEN. AS A RESULT...HAVE DECIDED NOT TO ISSUE ANY ADVISORY
HEADLINES FOR BLOWING SNOW AND KEEP THE WIND ADVISORY AS IS EXCEPT
FOR THE SOUTHEAST WHERE IT HAS BEEN EXTENDED IN TIME.
.LONG TERM...SUNDAY NIGHT THROUGH FRIDAY...
THE MAIN FORECAST ISSUES IN THE LONG TERM PERIOD WILL BE A COUPLE OF
LIGHT SNOW EVENTS OVER THE NORTHEAST HALF OF THE FORECAST AREA.
NORTHWEST FLOW WILL BE IN PLACE ACROSS THE REGION AT THE BEGINNING
OF THE LONG TERM PERIOD. MODEL CONSENSUS CONTINUES TO SUPPORT A FEW
PERIODS OF SHORT WAVE ENERGY DIVING SOUTHEAST INTO THE STATE. HAVE
INCREASED POPS ACROSS THE NORTH AND EAST FOR SUNDAY
NIGHT...MONDAY...AND MONDAY NIGHT. THESE AREAS ARE FAVORED FOR
MINOR ACCUMULATIONS RANGING FROM A DUSTING TO AROUND TWO INCHES.
COMPLICATING FACTORS SUCH AS STRONG WIND AND BLOWING SNOW ARE NOT
EXPECTED. FORECAST BUFR SOUNDINGS CONTINUE TO INDICATE A MODEST WARM
LAYER ALOFT AND THE POTENTIAL FOR SOME SLEET AT TIMES ON THE BACK
EDGE OF THE PRECIP. UPPER FLOW WILL TRANSITION FROM ZONAL TO
SOUTHWEST...TUESDAY THROUGH FRIDAY. SOME ADDITIONAL LIGHT SNOW COULD
CLIP THE FAR NORTH WEDNESDAY...OTHERWISE EXPECT MAINLY DRY WEATHER
WITH RELATIVELY MILD AFTERNOON HIGHS IN THE 20S AND 30S.
&&
.AVIATION...
LOW PRESSURE WILL DROP SOUTHEAST ACROSS CENTRAL AND INTO SOUTHEAST
NORTH DAKOTA ON SATURDAY. LIGHT NORTH TO NORTHWEST WINDS WILL SHIFT
SOUTH TO SOUTHWEST LATE TONIGHT THEN BACK NORTHWEST ON SATURDAY
BEHIND THE SURFACE LOW. WINDS WILL BECOME GUSTY BY SATURDAY
AFTERNOON THEN DIMINISH BY SATURDAY EVENING. WIDESPREAD MVFR-IFR
CEILINGS AND VISIBILITIES WILL REMAIN OVER WESTERN AND CENTRAL NORTH
DAKOTA AHEAD OF THE APPROACHING SURFACE LOW. LOWEST VISIBILITIES IN
SNOW WILL REMAIN FROM MINOT TO JAMESTOWN ON SATURDAY...CLOSE TO THE
TRACK OF THE LOW. EXPECT IMPROVING CEILINGS SATURDAY EVENING FROM
WEST TO EAST.
&&
.BIS WATCHES/WARNINGS/ADVISORIES...
WIND ADVISORY FROM 9 AM CST /8 AM MST/ THIS MORNING TO 6 PM CST
/5 PM MST/ THIS EVENING FOR NDZ001>003-009>011-017>021-031>035-
040>046.
WIND ADVISORY FROM NOON TODAY TO 6 PM CST THIS EVENING FOR
NDZ004-005-012-013-022-023-025-036-037-047-048-050-051.
&&
$$
SHORT TERM...HUBER
LONG TERM...KINNEY
AVIATION...HAMILTON
AREA FORECAST DISCUSSION
NWS GRAND FORKS ND
400 AM CST SAT FEB 2 2013
.SHORT TERM...TODAY THROUGH MONDAY NIGHT
MAIN FORECAST CHALLENGES INCLUDE LIGHT SNOW CHANCES AND TEMPERATURES.
GFS/NAM/ECMWF/GEM IN GOOD AGREEMENT AND WILL USE A BLENDED SOLUTION
FOR THIS FORECAST PACKAGE.
FOR TODAY...A CLIPPER SYSTEM IN NORTHWEST FLOW ALOFT WILL MOVE ACROSS
THE NORTHERN PLAINS. MOST OF THE FORECAST AREA WILL REMAIN ON THE COOL
SIDE OF THE SYSTEM AS THE SURFACE LOW TRACKS FROM CENTRAL SASKATCHEWAN
TO NORTHEAST SD. AFTERNOON HIGHS WILL MAINLY BE IN THE SINGLE DIGITS
TO LOW TEENS ABOVE ZERO...BUT AREAS WEST OF A LINE FROM DEVILS LAKE
TO VALLEY CITY TO LISBON MAY CLIMB INTO THE LOW 20S. CANADIAN RADARS
SHOW LIGHT SNOW SOUTH AND EAST OF THE SURFACE LOW AND THIS BAND IS
EXPECTED TO MOVE SOUTHEASTWARD THROUGH THE DAY...MAINLY IMPACTING
EASTERN ND INTO WEST CENTRAL MN. SLOWED THE TIMING OF THE HIGHEST
POPS AS LATEST RAP OUTPUT KEEPS MAJORITY OF PRECIPITATION OUT OF
THE FORECAST AREA UNTIL AFTER 15 UTC. TOTAL ACCUMULATIONS THROUGH
TONIGHT WILL GENERALLY BE AN INCH OR LESS.
REMAINING SNOW SHOWERS EXPECTED TO MOVE EAST OF THE FORECAST AREA
BY MIDNIGHT WITH DECREASING CLOUD COVER FROM WEST TO EAST. SUNDAY
MORNING LOWS EXPECTED IN THE 0 TO 10 BELOW RANGE...BUT WILL BE
HIGHLY DEPENDENT ON CLOUD COVER.
ANOTHER WEAK CLIPPER DROPS SOUTH ON SUNDAY...BRINGING A NARROW
BAND OF LIGHT SNOW FROM CENTRAL ND INTO SOUTHWEST MN. STRONG
SURFACE HIGH WILL MOVE INTO THE NORTHERN VALLEY BY 06 UTC MONDAY
AND THIS WILL LIMIT NORTHWARD EXTENT OF PRECIPITATION. MODEL
TRENDS PLACE SNOW FARTHER SOUTH...SO ADJUSTED HIGHEST POPS SOUTH
OF A LINE FROM DEVILS LAKE TO HILLSBORO TO PARK RAPIDS.
ACCUMULATIONS EXPECTED TO BE EVEN LESS THAN TODAY...GENERALLY A
HALF INCH OF LESS. SKIES WILL BE MOSTLY CLOUDY AND TEMPERATURES
WILL BE NEAR OR SLIGHTLY COOLER THAN TODAY IN THE WAKE OF TODAY/S
SYSTEM.
THE PARADE OF CLIPPERS CONTINUE INTO EARLY NEXT WEEK WITH A THIRD
WAVE ON MONDAY. THE TRACK OF THE SURFACE LOW IS A BIT FARTHER
NORTH...SO EXPECT GREATER SPATIAL COVERAGE OF ACCUMULATING
SNOWFALL. STRONG MID-LEVEL WARM AIR ADVECTION WILL COMBINE UPPER
JET DYNAMICS TO PRODUCE A COUPLE INCHES OF SNOW ACROSS THE
NORTHERN VALLEY INTO NORTHWEST MN. WITH TRACK OF THE LOW AND
ALIGNMENT OF THE BAROCLINIC AXIS...TEMPERATURES WILL BE A BIT
WARMER WITH AFTERNOON HIGHS MAINLY IN THE TEENS ABOVE ZERO.
MORNING LOWS WILL CONTINUE TO BE DEPENDENT ON CLOUD COVER...BUT
NOT EXPECTING MUCH DAY TO DAY CHANGE WITH THE COOLEST READINGS
ACROSS THE LAKE OF THE WOODS REGION.
.LONG TERM...TUESDAY THROUGH FRIDAY NIGHT
NW FLOW ALOFT WILL SLOWLY TRANSITION TO A MORE ZONAL/SW FLOW ALOFT
BY NEXT WEEKEND. THIS WILL MEAN GRADUALLY WARMING TEMPS ABOVE NORMAL
WITH MINIMAL CHANCES FOR PRECIP THROUGH SAT. THERE IS THE POTENTIAL
FOR SOME LINGERING LIGHT SNOW EARLY TUE IN THE EAST...AND IN THE
NORTH ON WED WITH SOME WAA. OTHERWISE...EXPECT A DRY EXTENDED WITH
A WARMING TREND. THERE ARE SOME HINTS AT A POTENTIAL STORM BY LATE
SAT INTO SUNDAY...WITH THE MAIN POTENTIAL IMPACTS AT THIS TIME
POSSIBLE IN THE SOUTHERN FORECAST AREA.
&&
.AVIATION...
VFR/MVFR CEILINGS WILL INCREASE FROM WEST TO EAST THROUGH THE DAY AS
A LOW PRESSURE SYSTEM MOVES ACROSS THE REGION. SOME LIGHT SNOW IS
POSSIBLE FOR AIRFIELDS ALONG AND WEST OF THE VALLEY AFTER 15 UTC.
SNOW SHOULD BE LIGHT...BUT SOME REDUCTIONS IN VISIBILITY LESS THAN
ONE MILE ARE POSSIBLE. LIGHT SOUTH-SOUTHWEST WIND THROUGH THE DAY
WILL INCREASE AND SHIFT TO THE NORTHWEST THIS EVENING AND
OVERNIGHT.
&&
.FGF WATCHES/WARNINGS/ADVISORIES...
ND...NONE.
MN...NONE.
&&
$$
ROGERS/DK
AREA FORECAST DISCUSSION
NWS BISMARCK ND
1249 AM CST SAT FEB 2 2013
.DISCUSSION...
LIGHT SNOW CONTINUES TO SLOWLY SPREAD EAST ACROSS WESTERN AND
CENTRAL NORTH DAKOTA EARLY THIS MORNING...WITH A SHARP GRADIENT
ALONG THE EASTERN PERIPHERY OF THE SURFACE HIGH PRESSURE OVER THE
EAST. THE DRY AIR ASSOCIATED WITH THIS SURFACE HIGH WILL CONTINUE
TO LIMIT THE EASTERN EXTENT OF THE AREA OF LIGHT SNOW. HAVE OPTED TO
TRIM BACK POPS/QPF ACROSS THE CENTRAL...USING THE LATEST RADAR DATA
AND RAP SOLUTION AS A GUIDE. OTHERWISE...MINOR ADJUSTMENTS TO ALL
OTHER GRIDS TO REFLECT CURRENT OBS AND TRENDS.
&&
.AVIATION...
LOW PRESSURE WILL DROP SOUTHEAST ACROSS ALBERTA AND
SASKATCHEWAN LATE TONIGHT THEN ACROSS CENTRAL AND INTO SOUTHEAST
NORTH DAKOTA ON SATURDAY. LIGHT NORTH TO NORTHWEST WINDS WILL SHIFT
SOUTH TO SOUTHWEST LATE TONIGHT THEN BACK NORTHWEST ON SATURDAY
BEHIND THE SURFACE LOW. WINDS WILL BECOME GUSTY BY SATURDAY
AFTERNOON THEN DIMINISH BY SATURDAY EVENING. WIDESPREAD MVFR-IFR
CEILINGS AND VISIBILITIES WILL REMAIN OVER WESTERN AND CENTRAL NORTH
DAKOTA AHEAD OF THE APPROACHING SURFACE LOW. LOWEST VISIBILITIES IN
SNOW WILL REMAIN FROM MINOT TO JAMESTOWN ON SATURDAY...CLOSE TO THE
TRACK OF THE LOW. EXPECT IMPROVING CEILINGS SATURDAY EVENING FROM
WEST TO EAST.
&&
.BIS WATCHES/WARNINGS/ADVISORIES...
WIND ADVISORY FROM 9 AM CST /8 AM MST/ THIS MORNING TO 6 PM CST
/5 PM MST/ THIS EVENING FOR NDZ001>003-009>011-017>021-031>035-
040>046.
WIND ADVISORY FROM NOON TODAY TO 6 PM CST THIS EVENING FOR
NDZ004-005-012-013-022-023-025-036-037-047-048-050-051.
&&
$$
SHORT TERM...HUBER
AVIATION...
AREA FORECAST DISCUSSION
NWS WILMINGTON OH
1235 PM EST SAT FEB 2 2013
.SYNOPSIS...
A CLIPPER SYSTEM WILL TRACK EAST ACROSS THE GREAT LAKES AND OHIO
VALLEY THROUGH TONIGHT. A WEAK UPPER LEVEL WEATHER DISTURBANCE
WILL AFFECT THE REGION ON SUNDAY. HIGH PRESSURE WILL BUILD BRIEFLY
INTO THE OHIO VALLEY SUNDAY NIGHT. THE HIGH WILL MOVE EAST ON
MONDAY AS ANOTHER CLIPPER SYSTEM QUICKLY MOVES TOWARD THE OHIO
VALLEY FROM THE NORTHWEST.
&&
.NEAR TERM /THROUGH TONIGHT/...
SNOW HAS OVERSPREAD THE FORECAST AREA. NAM AND RAP MODELS HAVE
GOOD REPRESENTATIONS OF THE AREA OF SNOW. ACCUMULATIONS HAVE BEEN
UP TO AN INCH IN SOUTHWEST COUNTIES.
THE BEST ISENTROPIC LIFT WILL OCCUR AHEAD OF THE WEAK SFC LOW AND
FRONT. THUS...MUCH OF THE SNOW ACCUMULATION WILL OCCUR DURING THE
DAYLIGHT HOURS. THE SNOW WILL TAPER OFF FROM WEST TO EAST THIS
EVENING AS THE CLIPPER MOVES OFF TO THE EAST. USING A BLEND OF
MODEL QPF AND SNOW TO LIQUID RATIOS BASED ON TEMPERATURE...IT
STILL LOOKS LIKE A GOOD 2 TO 3 INCH SNOW EVENT AREA WIDE WITH
ISOLATED AMOUNTS NEAR 4 INCHES. A WINTER WEATHER ADVISORY WILL
REMAIN IN EFFECT THROUGH TONIGHT.
WITH LOW LEVEL WAA...HIGHS TODAY SHOULD RANGE FROM THE MID 20S
NORTH TO THE LOWER 30S SOUTH. IN CAA BEHIND THE DEPARTING
CLIPPER...OVERNIGHT LOWS SHOULD RANGE FROM THE MID TEENS
NORTHWEST TO THE LOWER 20S SOUTHEAST.
&&
.SHORT TERM /SUNDAY THROUGH TUESDAY NIGHT/...
OUR REGION WILL REMAIN UNDER A NORTHWEST FLOW PATTERN ALOFT
THROUGH THE SHORT TERM PERIOD. THIS PATTERN WILL ALLOW SEVERAL
WEATHER SYSTEMS TO AFFECT THE AREA.
ON SUNDAY...A SHEARED OUT WEAK UPR LVL WX DISTURBANCE WILL PASS
ACRS THE REGION. THIS FEATURE WILL KEEP SKIES MAINLY CLOUDY ALONG
WITH A CHANCE OF SNOW SHOWERS. THE WEAK DISTURBANCE WILL EXIT THE
AREA BY SUNDAY EVENING. DESPITE SURFACE HIGH PRESSURE BRIEFLY
BUILDING INTO THE OHIO VALLEY...CLOUDS WILL CONTINUE TO SPILL
SOUTHEAST FROM THE NEXT CLIPPER SYSTEM WHICH WILL LIMIT ANY
OPPORTUNITY TO CLEAR OUT.
FOR MONDAY INTO MONDAY NIGHT...MODELS ALL INDICATE THAT A CLIPPER
SYSTEM WILL TRACK SOUTHEAST THROUGH THE OHIO VALLEY. AM CONFIDENT
ENOUGH AT THIS POINT TO RAISE POPS TO LIKELY FOR MONDAY AFTERNOON
INTO MONDAY NIGHT. THERE CONTINUES TO BE STRENGTH ISSUES WITH THE
LOW AND ITS ASSOCIATED WAA/LOW LEVEL JET WHICH WILL ULTIMATELY
DICTATE PCPN TYPE AND SNOW ACCUMULATIONS. AT THIS POINT IT LOOKS
LIKE MUCH OF THE AREA NORTH OF THE OHIO RIVER WILL SEE SNOW WHILE
RAIN MAY MIX WITH SNOW ALONG AND SOUTH OF THE RIVER MONDAY
AFTERNOON INTO MONDAY EVENING UNTIL CAA CHANGES THE PCPN TO ALL
SNOW BEFORE TAPERING OFF LATE. AGAIN...WE SHOULD SEE SOME
ACCUMULATIONS BUT AMOUNTS ARE STILL UNCERTAIN AT THIS POINT DUE TO
REASONS JUST MENTIONED. WILL SPELL THIS OUT IN THE HWO PRODUCT.
LITTLE RESPITE IS EXPECTED TUESDAY INTO TUESDAY NIGHT AS ANOTHER
CLIPPER SYSTEM WILL BE ON THE HEELS OF THE MONDAY/MONDAY NIGHT
SYSTEM. THERE CONTINUES TO BE PLACEMENT ISSUES WITH THIS FEATURE
IN HOW FAR SOUTH IT WILL DIG. HAVE KEPT POPS IN THE CHANCE
CATEGORY UNTIL MODELS RESOLVE THIS DILEMMA. PCPN WILL BE IN THE
FORM OF SNOW NORTH WITH RAIN/SNOW POSSIBLE SOUTH.
AS FOR TEMPERATURES...THEY WILL BE HARD TO PINPOINT GIVEN SNOW
COVER AND SURFACE LOW PLACEMENT WITH THE UPCOMING CLIPPER SYSTEMS
WHICH WILL RESULT IN SFC WAA AHEAD OF THE LOW CENTER. MAINLY USED
A BLEND OF THE GFS/ECMWF SURFACE TEMPERATURES ALONG WITH
CLIMATOLOGICAL THICKNESS SCHEMES.
&&
.LONG TERM /WEDNESDAY THROUGH FRIDAY/...
HIGH PRESSURE WILL BE IN PLACE ACROSS THE AREA FOR WEDNESDAY AND
WILL MOVE EAST OF THE FA ON THURSDAY. WITH SOUTHERLY FLOW ON
THURSDAY TEMPERATURES WILL RANGE FROM THE MIDDLE 30S TO THE MIDDLE
40S ACROSS THE REGION. PRECIPITATION WILL BEGIN TO MOVE INTO THE
FA THURSDAY EVENING AND BECOME MORE WIDESPREAD ACROSS THE AREA
THURSDAY NIGHT AS A COLD FRONT APPROACHES AND MOVES THROUGH THE
REGION. PRECIPITATION WILL TAPER OFF ACROSS THE FA DURING THE
MORNING HOURS ON FRIDAY AND HIGH PRESSURE WILL WORK BACK INTO THE
REGION FRIDAY AFTERNOON.
&&
.AVIATION /18Z SATURDAY THROUGH WEDNESDAY/...
SNOW WILL CONTINUE TO IMPACT AVIATION. VISIBILITIES AS LOW AS IFR
WILL PERSIST THIS AFTERNOON UNTIL WEAK LOW PRESSURE AND BANDS OF
SNOW MOVE EAST. SINCE MODELS HAVE LOW LEVEL MOISTURE REMAINING IN
PLACE...MVFR CEILINGS SHOULD LINGER THROUGH THE END OF THE TAF
PERIOD. WINDS WILL GUST CLOSE TO 20 KNOTS OUT OF THE SOUTH TO
SOUTHWEST THIS AFTERNOON. LOOK FOR A SHIFT IN DIRECTION TO WEST
TONIGHT BEHIND THE WEAK LOW. MORE SNOW SHOWERS ARE EXPECTED ON
SUNDAY DUE TO A WEAK DISTURBANCE IN THE JET STREAM.
OUTLOOK...MVFR TO IFR CONDITIONS ARE EXPECTED AGAIN ON MONDAY
AND MONDAY NIGHT.
&&
.ILN WATCHES/WARNINGS/ADVISORIES...
OH...WINTER WEATHER ADVISORY UNTIL 7 AM EST SUNDAY FOR OHZ026-034-
035-042>046-051>056-060>065-070>074-077>082-088.
KY...WINTER WEATHER ADVISORY UNTIL 7 AM EST SUNDAY FOR KYZ089>100.
IN...WINTER WEATHER ADVISORY UNTIL 7 AM EST SUNDAY FOR INZ050-058-
059-066-073>075-080.
&&
$$
SYNOPSIS...HICKMAN
NEAR TERM...CONIGLIO/HICKMAN
SHORT TERM...HICKMAN
LONG TERM...NOVAK
AVIATION...CONIGLIO
AREA FORECAST DISCUSSION
NWS WILMINGTON OH
934 AM EST SAT FEB 2 2013
.SYNOPSIS...
A CLIPPER SYSTEM WILL TRACK EAST ACROSS THE GREAT LAKES AND OHIO
VALLEY THROUGH TONIGHT. A WEAK UPPER LEVEL WEATHER DISTURBANCE
WILL AFFECT THE REGION ON SUNDAY. HIGH PRESSURE WILL BUILD BRIEFLY
INTO THE OHIO VALLEY SUNDAY NIGHT. THE HIGH WILL MOVE EAST ON
MONDAY AS ANOTHER CLIPPER SYSTEM QUICKLY MOVES TOWARD THE OHIO
VALLEY FROM THE NORTHWEST.
&&
.NEAR TERM /THROUGH TONIGHT/...
SNOW HAS OVERSPREAD THE FORECAST AREA. NAM AND RAP MODELS HAVE
GOOD REPRESENTATIONS OF THE AREA OF SNOW. ACCUMULATIONS HAVE BEEN
UP TO AN INCH IN SOUTHWEST COUNTIES.
THE BEST ISENTROPIC LIFT WILL OCCUR AHEAD OF THE WEAK SFC LOW AND
FRONT. THUS...MUCH OF THE SNOW ACCUMULATION WILL OCCUR DURING THE
DAYLIGHT HOURS. THE SNOW WILL TAPER OFF FROM WEST TO EAST THIS
EVENING AS THE CLIPPER MOVES OFF TO THE EAST. USING A BLEND OF
MODEL QPF AND SNOW TO LIQUID RATIOS BASED ON TEMPERATURE...IT
STILL LOOKS LIKE A GOOD 2 TO 3 INCH SNOW EVENT AREA WIDE WITH
ISOLATED AMOUNTS NEAR 4 INCHES. A WINTER WEATHER ADVISORY WILL
REMAIN IN EFFECT THROUGH TONIGHT.
WITH LOW LEVEL WAA...HIGHS TODAY SHOULD RANGE FROM THE MID 20S
NORTH TO THE LOWER 30S SOUTH. IN CAA BEHIND THE DEPARTING
CLIPPER...OVERNIGHT LOWS SHOULD RANGE FROM THE MID TEENS
NORTHWEST TO THE LOWER 20S SOUTHEAST.
&&
.SHORT TERM /SUNDAY THROUGH TUESDAY NIGHT/...
OUR REGION WILL REMAIN UNDER A NORTHWEST FLOW PATTERN ALOFT
THROUGH THE SHORT TERM PERIOD. THIS PATTERN WILL ALLOW SEVERAL
WEATHER SYSTEMS TO AFFECT THE AREA.
ON SUNDAY...A SHEARED OUT WEAK UPR LVL WX DISTURBANCE WILL PASS
ACRS THE REGION. THIS FEATURE WILL KEEP SKIES MAINLY CLOUDY ALONG
WITH A CHANCE OF SNOW SHOWERS. THE WEAK DISTURBANCE WILL EXIT THE
AREA BY SUNDAY EVENING. DESPITE SURFACE HIGH PRESSURE BRIEFLY
BUILDING INTO THE OHIO VALLEY...CLOUDS WILL CONTINUE TO SPILL
SOUTHEAST FROM THE NEXT CLIPPER SYSTEM WHICH WILL LIMIT ANY
OPPORTUNITY TO CLEAR OUT.
FOR MONDAY INTO MONDAY NIGHT...MODELS ALL INDICATE THAT A CLIPPER
SYSTEM WILL TRACK SOUTHEAST THROUGH THE OHIO VALLEY. AM CONFIDENT
ENOUGH AT THIS POINT TO RAISE POPS TO LIKELY FOR MONDAY AFTERNOON
INTO MONDAY NIGHT. THERE CONTINUES TO BE STRENGTH ISSUES WITH THE
LOW AND ITS ASSOCIATED WAA/LOW LEVEL JET WHICH WILL ULTIMATELY
DICTATE PCPN TYPE AND SNOW ACCUMULATIONS. AT THIS POINT IT LOOKS
LIKE MUCH OF THE AREA NORTH OF THE OHIO RIVER WILL SEE SNOW WHILE
RAIN MAY MIX WITH SNOW ALONG AND SOUTH OF THE RIVER MONDAY
AFTERNOON INTO MONDAY EVENING UNTIL CAA CHANGES THE PCPN TO ALL
SNOW BEFORE TAPERING OFF LATE. AGAIN...WE SHOULD SEE SOME
ACCUMULATIONS BUT AMOUNTS ARE STILL UNCERTAIN AT THIS POINT DUE TO
REASONS JUST MENTIONED. WILL SPELL THIS OUT IN THE HWO PRODUCT.
LITTLE RESPITE IS EXPECTED TUESDAY INTO TUESDAY NIGHT AS ANOTHER
CLIPPER SYSTEM WILL BE ON THE HEELS OF THE MONDAY/MONDAY NIGHT
SYSTEM. THERE CONTINUES TO BE PLACEMENT ISSUES WITH THIS FEATURE
IN HOW FAR SOUTH IT WILL DIG. HAVE KEPT POPS IN THE CHANCE
CATEGORY UNTIL MODELS RESOLVE THIS DILEMMA. PCPN WILL BE IN THE
FORM OF SNOW NORTH WITH RAIN/SNOW POSSIBLE SOUTH.
AS FOR TEMPERATURES...THEY WILL BE HARD TO PINPOINT GIVEN SNOW
COVER AND SURFACE LOW PLACEMENT WITH THE UPCOMING CLIPPER SYSTEMS
WHICH WILL RESULT IN SFC WAA AHEAD OF THE LOW CENTER. MAINLY USED
A BLEND OF THE GFS/ECMWF SURFACE TEMPERATURES ALONG WITH
CLIMATOLOGICAL THICKNESS SCHEMES.
&&
.LONG TERM /WEDNESDAY THROUGH FRIDAY/...
HIGH PRESSURE WILL BE IN PLACE ACROSS THE AREA FOR WEDNESDAY AND
WILL MOVE EAST OF THE FA ON THURSDAY. WITH SOUTHERLY FLOW ON
THURSDAY TEMPERATURES WILL RANGE FROM THE MIDDLE 30S TO THE MIDDLE
40S ACROSS THE REGION. PRECIPITATION WILL BEGIN TO MOVE INTO THE
FA THURSDAY EVENING AND BECOME MORE WIDESPREAD ACROSS THE AREA
THURSDAY NIGHT AS A COLD FRONT APPROACHES AND MOVES THROUGH THE
REGION. PRECIPITATION WILL TAPER OFF ACROSS THE FA DURING THE
MORNING HOURS ON FRIDAY AND HIGH PRESSURE WILL WORK BACK INTO THE
REGION FRIDAY AFTERNOON.
&&
.AVIATION /15Z SATURDAY THROUGH WEDNESDAY/...
SNOW IS NOW MOVING INTO THE TAF SITES...WITH VISIBILITIES QUICKLY
DROPPING INTO THE IFR CATEGORY JUST AFTER PRECIPITATION ONSET.
CEILINGS IN THE SNOW ARE ANYWHERE FROM VFR TO IFR...THOUGH IFR
CEILINGS HAVE BEEN FAIRLY UNCOMMON FOR THE PAST FEW HOURS. THE
TAFS WILL HANDLE THE BRUNT OF THE SNOW (OVER THE COURSE OF THE
NEXT 4-8 HOURS) WITH PREVAILING IFR VISIBILITIES AND LOW-END MVFR
CEILINGS IN A TEMPO. MVFR CEILINGS ARE EXPECTED TO BE THE RULE
LATER IN THE DAY...WITH LOW LEVEL MOISTURE FORECAST TO
INCREASE...EVEN AS THE STEADY PRECIPITATION COMES TO AN END. SNOW
SHOWERS LATER IN THE DAY MAY STILL BE CAPABLE OF BRIEF IFR
VISIBILITIES...BUT IN GENERAL MVFR CONDITIONS ARE EXPECTED.
AS SNOW TAPERS OFF DURING THE EVENING AND INTO THE OVERNIGHT
HOURS...VISIBILITIES SHOULD GO VFR...WITH SOME LOW CEILINGS
(GENERALLY MVFR) STILL REMAINING IN PLACE. HOWEVER...SOME
SCATTERING OF THE CLOUD DECK WILL BE EXPECTED.
OUTLOOK...MVFR CONDITIONS WILL CONTINUE TO BE POSSIBLE ON SUNDAY.
MVFR TO IFR CONDITIONS ARE EXPECTED AGAIN ON MONDAY AND MONDAY
NIGHT.
&&
.ILN WATCHES/WARNINGS/ADVISORIES...
OH...WINTER WEATHER ADVISORY UNTIL 7 AM EST SUNDAY FOR OHZ026-034-
035-042>046-051>056-060>065-070>074-077>082-088.
KY...WINTER WEATHER ADVISORY UNTIL 7 AM EST SUNDAY FOR KYZ089>100.
IN...WINTER WEATHER ADVISORY UNTIL 7 AM EST SUNDAY FOR INZ050-058-
059-066-073>075-080.
&&
$$
SYNOPSIS...HICKMAN
NEAR TERM...CONIGLIO/HICKMAN
SHORT TERM...HICKMAN
LONG TERM...NOVAK
AVIATION...HATZOS
AREA FORECAST DISCUSSION
NWS NORMAN OK
951 PM CST SUN FEB 3 2013
.UPDATE...
VERY MIXED SIGNALS FROM THE NUMERIC MODELS ABOUT PRECIPITATION
POTENTIAL OVERNIGHT. LOCAL WRF DEVELOPS WIDESPREAD LIGHT
PRECIPITATION... HRRR DOES AS WELL LATE... BUT OTHERS KEEP IT DRY.
WOULD NOT BE SURPRISED TO SEE RADAR ECHOES INCREASE OVERNIGHT BUT
00Z RAOB SHOWS A DEEP LAYER OF DRY AIR BELOW 475 MB SO WOULD
EXPECT MOSTLY VIRGA. SURFACE OBS ACROSS THE SOUTHERN PLAINS DO NOT
SHOW SIGNIFICANT INCREASE IN SURFACE DEWPOINTS POISED TO MOVE IN
EITHER. WILL KEEP POPS AS THEY ARE WITH THE RELATIVELY LOW POPS IN
EAST. MADE SOME ADJUSTMENTS TO THE HOURLY GRIDS BUT THESE WILL NOT
REQUIRE UPDATING THE TEXT PRODUCTS.
&&
.PREV DISCUSSION... /ISSUED 543 PM CST SUN FEB 3 2013/
AVIATION...
04/00Z TAFS...VFR CONDITIONS EXPECTED TO PREVAIL. LLWS WILL BE
INCLUDED FROM KSPS/KLAW UP THROUGH KOKC AND KPNC OVERNIGHT WITH
40-45KT LOW-LEVEL JET IN PLACE. COLD FRONT WILL APPROACH NORTHWEST
OKLAHOMA TERMINALS TOWARD 12Z AND MOVE OVER ALL TERMINALS BY 18Z
SHIFTING WINDS TO NORTH-NORTHEAST. APPEARS THAT SHOWERS LATE
TONIGHT AND TOMORROW WILL STAY EAST OF TERMINALS.
PREV DISCUSSION... /ISSUED 326 PM CST SUN FEB 3 2013/
DISCUSSION...
UPDATED TO CORRECT THE POINT TEMPS/POPS BELOW THE DISCUSSION.
MILD WEEK UP COMING WITH SEVERAL CHANCES FOR RAIN ACROSS
OKLAHOMA AND WESTERN NORTH TEXAS.
THE FIRST CHANCE FOR RAIN WILL COME LATE TONIGHT AND MONDAY AS A
MINOR DISTURBANCE MOVES OUT OF THE CENTRAL AND SOUTHERN ROCKIES
AND INTERACTS WITH RETURNING MOISTURE. ALTHOUGH MODELS HAVE BACKED
OFF ON OVERNIGHT ACTIVITY... STILL APPEARS THAT A FEW SHOWERS MAY
DEVELOP AFTER MIDNIGHT... MAINLY SOUTH AND EAST OF A ALTUS... TO
WATONGA... ENID AND PONCA CITY LINE. BETTER RAIN CHANCES WILL BE
ACROSS SOUTHEAST OKLAHOMA ON MONDAY AS A SFC COLD FRONT MOVES INTO
BETTER MOISTURE.
NOT MUCH IN THE WAY OF COLD AIR BEHIND THIS FRONT... SO A COUPLE
OF MILD AND DRY DAYS ON TAP FOR TUESDAY AND WEDNESDAY. RAIN
CHANCES REENTER THE PICTURE WEDNESDAY NIGHT INTO THURSDAY AS
ANOTHER COLD FRONT SLIPS SOUTH INTO OKLAHOMA. ALTHOUGH LOW LEVEL
MOISTURE WILL BE SOMEWHAT LIMITED... STILL EXPECT SOME SHOWERS
ALONG AND AHEAD OF FRONT.
BY THE END OF THE WEEK... MUCH STRONGER AND DEEPER UPPER TROUGH
TAKES SHAPE ACROSS THE WESTERN U.S. AS THIS OCCURS STRENGTHENING
SOUTHERLY FLOW WILL BRING MUCH RICHER MOISTURE NORTHWARD ACROSS
THE SOUTHERN PLAINS. ALTHOUGH MODELS DO STILL HAVE SOME TIMING
DIFFERENCES... LOOKS TO BE A FAIRLY ACTIVE WEEKEND WITH THE
POTENTIAL FOR MORE WIDESPREAD SHOWERS AND THUNDERSTORMS ACROSS
OKLAHOMA AND WESTERN NORTH TEXAS. NOT OUT OF THE QUESTION TO SEE A
FEW SEVERE STORMS WITH THIS SYSTEM.
&&
.PRELIMINARY POINT TEMPS/POPS...
OKLAHOMA CITY OK 45 59 31 62 / 20 30 0 0
HOBART OK 46 61 29 63 / 20 20 0 0
WICHITA FALLS TX 48 64 36 64 / 20 30 0 0
GAGE OK 37 57 22 61 / 10 10 0 0
PONCA CITY OK 42 57 24 60 / 20 20 0 0
DURANT OK 49 59 39 64 / 30 70 10 0
&&
.OUN WATCHES/WARNINGS/ADVISORIES...
OK...NONE.
TX...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS GREENVILLE-SPARTANBURG SC
919 PM EST SUN FEB 3 2013
.SYNOPSIS...
A LARGE UPPER LEVEL TROF WILL SWING EAST OF THE REGION MONDAY BEFORE
A WEAK COLD FRONT PUSHES INTO THE NORTH CAROLINA MOUNTAINS TUESDAY.
DRY HIGH PRESSURE WILL DOMINATE THE WEATHER PATTERN WEDNESDAY
THROUGH THURSDAY AFTERNOON...WHEN A STORM SYSTEM IS EXPECTED TO
AFFECT THE AREA FROM THE SOUTHWEST.
&&
.NEAR TERM /THROUGH MONDAY/...
AS OF 915 PM SUNDAY...THE ADVISORIES HAVE BEEN DROPPED OUTSIDE OF
THE NORTHERN MOUNTAINS WITH THIS PACKAGE. A BRIEF SURGE OF LOW LEVEL
MOISTURE COULD STILL BRING LIGHT SNOW AND FREEZING DRIZZLE TO THE
NORTHERN MOUNTAINS...AND THE ADVISORIES WILL REMAIN IN EFFECT IN
THOSE LOCATIONS UNTIL 1 AM.
AS OF 630 PM SUNDAY...THE GOING FORECAST IS IN GOOD SHAPE.
BLACKSBURG HAS ISSUED A HIGH WIND WARNING FOR THEIR NRN MTN
COUNTIES...THOUGH THE WNW FLOW FAVORS STRONGER FLOW UP ACROSS
WATAUGA AND ASHE COUNTIES. OUR WIND ADVISORY SHOULD COVER IT. NAM
AND RUC CROSS-SECTIONS DO SHOW A HINT OF A CRITICAL LEVEL OVER THE
LEE SLOPES UP AROUND 700 MB...BUT IT/S NOT THAT STRONG AND WINDS ARE
ONLY AROUND 50-55 KTS ABOVE THE RIDGES. I JUST DON/T SEE STRONG
WINDS COMING DOWN IN OUR AREA IN THIS CASE. I COULD PROBABLY CANCEL
THE WINTER WX ADVISORY AS CLOUDS ARE BREAKING UP QUICKLY ALONG TN
LINE. HOWEVER...BLACK ICE AND BLOWING SNOW ARE ENOUGH OF A THREAT
THAT I/LL KEEP IT UP THROUGH THIS UPDATE AT LEAST.
AS OF 200 PM SUNDAY...HIGH PRESSURE CURRENTLY CENTERED OVER THE
LOWER MISSISSIPPI VALLEY WILL SHIFT EASTWARD THROUGH THE PERIOD.
MOST AREAS WILL THUS SEE QUIET CONDITIONS. UPPER TROUGHING STILL
EVIDENT OVER THE EASTERN SEABOARD THIS AFTERNOON WITH COLD TEMPS
ALOFT LEADING TO STRONG LLVL LAPSE RATES AND DEEP MIXING. THIS
ALLOWED A FAIRLY ROBUST CU FIELD TO BREAK OUT AND THESE CLOUDS
SHOULD PERSIST UNTIL LATE AFTERNOON OVER MUCH OF THE CWFA. GIVEN THE
STRONG HEIGHT GRADIENT AROUND THE UPPER TROUGH...MIXING IS REACHING
WINDS OF 30-40 KT WITH ENOUGH MOMENTUM COMING DOWN TO PRODUCE GUSTS
OF 25-30 KT. NORTHWEST FLOW WILL CONTINUE TONIGHT...WITH ASSOCIATED
COLD ADVECTION ALLOWING MIXING TO CONTINUE OVER THE MTNS AND
FOOTHILLS WELL INTO THE EVENING. STRONG GUSTS WILL CONTINUE TO BE A
CONCERN IN THESE AREAS WITH THE NAM INDICATING A PEAK AROUND 03Z.
HAVE EXTENDED THE WIND ADVISORY UNTIL 06Z IN THE ZONES WHERE IT IS
ALREADY IN EFFECT.
DESPITE MOISTURE BECOMING MORE SHALLOW...SAID NORTHWEST FLOW WILL
LIKELY CONTINUE TO PRODUCE LIGHT PRECIP TONIGHT IN THE FAVORED AREAS
NORTH OF THE FRENCH BROAD VALLEY. THE COLD ADVECTION WILL ALLOW
TEMPS TO COOL ENOUGH THAT ICE NUCLEATION COULD OCCUR CLOSE TO THE
SURFACE SO SNOW IS LIKELY...BUT FREEZING DRIZZLE OR RIME ICING COULD
OCCUR INSTEAD. IN LIGHT OF THE CONTINUING WINTER PRECIP ALONG WITH
THE AFOREMENTIONED STRONG WIND GUSTS...BUT LACKING MUCH ADDITIONAL
ACCUMULATION...THE WINTER STORM WARNING IN EFFECT FOR MADISON CO
NORTHWARD TO AVERY CO WILL BE REPLACED WITH A WINTER WX ADVISORY.
THIS WILL ENCOMPASS THE VARIOUS THREATS...INCLUDING UNCOMFORTABLY
COLD WIND CHILLS. FOR LOW TEMPS...CHOSE TO FOLLOW BIAS CORRECTED GFS
MOS WHICH HAS PERFORMED WELL WITH SIMILAR WX CONDITIONS LATELY.
THE NORTHWEST FLOW SHOULD RELAX IN INTENSITY LATE TONIGHT AS THE SFC
HIGH PUSHES OVERHEAD AND FLOW TURNS MORE WESTERLY AT MID-UPPER
LEVELS...WITH SW WINDS IN THE LOW LEVELS. CIRRUS ARE EXPECTED TO
SPREAD OVER AS UPPER MOISTURE INCREASES AHEAD OF NEXT SYSTEM. TEMPS
WILL REBOUND TO NEAR NORMAL.
&&
.SHORT TERM /MONDAY NIGHT THROUGH WEDNESDAY/...
AS OF 145 PM SUNDAY...THE MAIN STORY OF THE SHORT TERM WILL BE THE
PATTERN TRANSITION FROM BROAD EASTERN TROUGHING TO A FAST QUASI-
ZONAL FLOW BY THE END OF PERIOD. IN THE INTERIM...YET ANOTHER UPPER
DISTURBANCE WILL APPROACH THE AREA WITHIN NW FLOW MONDAY EVENING...
WITH ANOTHER ROUND OF MOISTURE IMPACTING THE WESTERN NC MTNS AFTER
MIDNIGHT. THE GFS REMAINS VERY STINGY WITH QPF...WHILE THE NAM
SQUEEZES OUT A COUPLE OF TENTHS OF AN INCH ACROSS THE TENNESSEE
BORDER AREAS THROUGH TUESDAY MORNING. BASED UPON ENSEMBLE
GUIDANCE...AS WELL AS THE FACT THAT THE GFS SEEMS TO BE TRENDING
SLOWLY TOWARD A SLIGHTLY WETTER SOLUTION...POPS HAVE BEEN INCREASED
TO 40-50 PERCENT ALONG MUCH OF THE TENN BORDER. NEVERTHELESS...OTHER
THAN THE PERSISTENT UPSLOPE FLOW...IT APPEARS THAT FORCING WILL BE
VERY LIMITED...SO QPF SHOULD BE FAIRLY LIGHT. P-TYPE IS NOT
PARTICULARLY CLEAR CUT...AS THE COOL AIR MASS CONTINUES TO MODIFY
OVER THE AREA. IT DOES APPEAR THAT SNOW WILL BE THE MOST LIKELY
P-TYPE...WITH A POSSIBLE TRANSITION TO RAIN BY TUESDAY MORNING...AS
THE ATMOSPHERE DRIES OUT FROM ABOVE. SOME POCKETS OF FREEZING RAIN
WILL BE POSSIBLE WHERE COLD AIR IS TRAPPED IN SHELTERED VALLEYS. AS
FOR THE REMAINDER OF THE AREA...THE SHORT TERM MODELS APPEAR TO BE
REACHING A CONSENSUS THAT PRECIP ASSOCIATED WITH WEAK SURFACE WAVE
DEVELOPMENT TO OUR SOUTHWEST WILL REMAIN WELL SOUTH OF THE FORECAST
AREA.
WITH RISING HEIGHTS ALOFT...TEMPERATURES WILL WARM TO ABOVE CLIMO BY
THE END OF THE PERIOD...WITH MANY AREAS ACROSS THE PIEDMONT LIKELY
HITTING THE 60 DEGREE MARK BY WEDNESDAY AFTERNOON.
&&
.LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY/...
AS OF 145 PM SUNDAY...CONFIDENCE IN THE UPPER PATTERN IS ABOUT
AVERAGE IN THE MEDIUM RANGE...BUT BELOW AVERAGE IN THE FCST DETAILS.
A SPLIT FLOW IN THE WEST AND CONFLUENT NWLY FLOW IN THE EAST WILL
TRANSITION BACK TO A DEEP WESTERN TROF AND AN AMPLIFYING EASTERN
RIDGE OVER THE WEEKEND.
THE MEDIUM RANGE STARTS OUT WITH SFC HIGH PRES CENTERED OVER THE ST.
LAWRENCE VALLEY...WITH A WEDGE DOWN THE EAST SIDE OF THE
APPALACHIANS WEDNESDAY NIGHT. AS THE PATTERN CHANGES...A FAIRLY
STRONG SHORTWAVE TROF WILL CROSS THE GREAT LAKES THURSDAY...WITH A
WEAKER SOUTHERN STREAM TROF ACRS THE LOWER MS VALLEY. THERE IS
UNCERTAINTY ON HOW MUCH MOISTURE THESE SYSTEMS WILL PICK UP AS THEY
CROSS THE APPALACHIANS/CWFA THURSDAY NIGHT INTO FRIDAY. THE 12Z GFS
HAS COME IN WETTER WITH A STRONGER SOUTHERN SYSTEM. HOWEVER...I WILL
STICK WITH THE SLGT CHC POPS OF HPC FOR NOW...GIVEN THE UNCERTAINTY.
I WILL NOTE THAT THE LAST FEW SYSTEMS HAVE SEEMED TO VERIFY WETTER
THAN THEY WERE DEPICTED...EVEN JUST A COUPLE DAYS OUT. SO POPS MAY
TREND UP IN THE NEXT FEW CYCLES DURING THIS PERIOD...IF MODELS
CONVERGE ON A SOLN. AS I WRITE THIS...THE 12Z ECMWF HAS COME IN
STUBBORNLY HOLDING ONTO A NOREASTER SIMILAR TO THE 00Z RUN FOR
FRIDAY. FORTUNATELY...THICKNESSES IN BOTH THE ECWMF AND GFS LOOK TO
SUPPORT PRIMARILY LIQUID PRECIP ACRS THE REGION.
BEHIND THAT SYSTEM...ANOTHER SFC HIGH SETTLES INTO SE CANADA AND THE
NE STATES FRIDAY NIGHT THRU SUNDAY...RESULTING IN ANOTHER WEDGE. THE
WEDGE LOOKS DRY ON THE GFS...BUT WETTER ON THE GEFS ENSEMBLE (AND
THAT GOES FOR THE THURSDAY SYSTEM TOO). GIVEN THE UPPER RIDGE AXIS
OVER THE AREA SATURDAY AND SUNDAY...I WILL UNDERCUT THE HPC POPS
UNTIL LATE SUNDAY WITH THE RETURN FLOW...AS SFC RIDGE SHIFTS OFF THE
EAST COAST. TEMPS ARE MOST UNCERTAIN THURSDAY AND FRIDAY...DUE TO
COLD AIR DAMMING AND POP UNCERTAINTY. GUIDANCE HAS TEMPS WARMING TO
ABOVE NORMAL FOR THE WEEKEND (BUT COLD AIR DAMMING ON SATURDAY MAY
NEGATE THE EFFECTS OF RISING HEIGHTS ALOFT).
&&
.AVIATION /02Z MONDAY THROUGH FRIDAY/...
AT KCLT...NW WINDS WILL CONTINUE THROUGH THE NIGHT..THOUGH SPEEDS
WILL BECOME LIGHT BY MIDNIGHT. WINDS WILL TURN OUT OF THE SOUTHWEST
BY LATE MORNING AND INCREASE TO 7 TO 8 KTS BY LATE AFTN. IN
FACT...THAT MIGHT BE A LITTLE LOW AS THE NAM BUFKIT SOUNDINGS IMPLY
SPEEDS MAY BE CLOSER TO 10KTS WILL GUSTS UP TO 18 TO 20 KTS. I
DIDN/T GO THAT HIGH AS HIGH CLOUDS WILL BE FAIRLY DENSE BY LATE AFTN
WHICH SHOULD KEEP DOWN THE MIXING A LITTLE.
ELSEWHERE...WNW TO NW WINDS WILL GUST UP TO 20 KTS FOR A COUPLE MORE
HOURS. OVER THE FOOTHILLS AND PIEDMONT...THEN BECOME LIGHT
OVERNIGHT. KAVL WILL SEE STRONGER GUSTS THROUGH LATE EVENING BEFORE
THE WINDS START TO LET UP. WINDS WILL SHIFT OUT OF THE SW BY LATE
MORNING MONDAY...INCREASING TO AROUND 8 KTS AT MOST SITES BY MID
AFTN. HIGH CLOUD WILL GRADUALLY THICKEN THROUGH THE PERIOD.
OUTLOOK...SOME LIGHT WINTRY WEATHER MAY AFFECT KAVL MONDAY NIGHT.
OTHERWISE FAIR WEATHER THROUGH LATE WEEK.
AN EXPERIMENTAL AVIATION FORECAST CONSISTENCY TABLE SHOWING THE
PERCENTAGE OF GUIDANCE MEMBERS AGREEING WITH THE SCHEDULED ISSUANCE
CATEGORY IS AVAILABLE AT THE FOLLOWING LINK (USE LOWER CASE)...
WWW.WEATHER.GOV/GSP/AVIATION_TABLES
&&
.GSP WATCHES/WARNINGS/ADVISORIES...
GA...NONE.
NC...WIND ADVISORY UNTIL 1 AM EST MONDAY FOR NCZ501-503-505.
WINTER WEATHER ADVISORY UNTIL 1 AM EST MONDAY FOR NCZ033-049-
050.
SC...NONE.
&&
$$
SYNOPSIS...SBK
NEAR TERM...MCAVOY/WIMBERLEY
SHORT TERM...JDL
LONG TERM...ARK
AVIATION...MCAVOY
AREA FORECAST DISCUSSION
NWS GREENVILLE-SPARTANBURG SC
640 PM EST SUN FEB 3 2013
.SYNOPSIS...
A LARGE UPPER LEVEL TROF WILL SWING EAST OF THE REGION MONDAY BEFORE
A WEAK COLD FRONT PUSHES INTO THE NORTH CAROLINA MOUNTAINS TUESDAY.
DRY HIGH PRESSURE WILL DOMINATE THE WEATHER PATTERN WEDNESDAY
THROUGH THURSDAY AFTERNOON...WHEN A STORM SYSTEM IS EXPECTED TO
AFFECT THE AREA FROM THE SOUTHWEST.
&&
.NEAR TERM /THROUGH MONDAY/...
AS OF 630 PM SUNDAY...THE GOING FORECAST IS IN GOOD SHAPE.
BLACKSBURG HAS ISSUED A HIGH WIND WARNING FOR THEIR NRN MTN
COUNTIES...THOUGH THE WNW FLOW FAVORS STRONGER FLOW UP ACROSS
WATAUGA AND ASHE COUNTIES. OUR WIND ADVISORY SHOULD COVER IT. NAM
AND RUC CROSS-SECTIONS DO SHOW A HINT OF A CRITICAL LEVEL OVER THE
LEE SLOPES UP AROUND 700 MB...BUT IT/S NOT THAT STRONG AND WINDS ARE
ONLY AROUND 50-55 KTS ABOVE THE RIDGES. I JUST DON/T SEE STRONG
WINDS COMING DOWN IN OUR AREA IN THIS CASE. I COULD PROBABLY CANCEL
THE WINTER WX ADVISORY AS CLOUDS ARE BREAKING UP QUICKLY ALONG TN
LINE. HOWEVER...BLACK ICE AND BLOWING SNOW ARE ENOUGH OF A THREAT
THAT I/LL KEEP IT UP THROUGH THIS UPDATE AT LEAST.
AS OF 200 PM SUNDAY...HIGH PRESSURE CURRENTLY CENTERED OVER THE
LOWER MISSISSIPPI VALLEY WILL SHIFT EASTWARD THROUGH THE PERIOD.
MOST AREAS WILL THUS SEE QUIET CONDITIONS. UPPER TROUGHING STILL
EVIDENT OVER THE EASTERN SEABOARD THIS AFTERNOON WITH COLD TEMPS
ALOFT LEADING TO STRONG LLVL LAPSE RATES AND DEEP MIXING. THIS
ALLOWED A FAIRLY ROBUST CU FIELD TO BREAK OUT AND THESE CLOUDS
SHOULD PERSIST UNTIL LATE AFTERNOON OVER MUCH OF THE CWFA. GIVEN THE
STRONG HEIGHT GRADIENT AROUND THE UPPER TROUGH...MIXING IS REACHING
WINDS OF 30-40 KT WITH ENOUGH MOMENTUM COMING DOWN TO PRODUCE GUSTS
OF 25-30 KT. NORTHWEST FLOW WILL CONTINUE TONIGHT...WITH ASSOCIATED
COLD ADVECTION ALLOWING MIXING TO CONTINUE OVER THE MTNS AND
FOOTHILLS WELL INTO THE EVENING. STRONG GUSTS WILL CONTINUE TO BE A
CONCERN IN THESE AREAS WITH THE NAM INDICATING A PEAK AROUND 03Z.
HAVE EXTENDED THE WIND ADVISORY UNTIL 06Z IN THE ZONES WHERE IT IS
ALREADY IN EFFECT.
DESPITE MOISTURE BECOMING MORE SHALLOW...SAID NORTHWEST FLOW WILL
LIKELY CONTINUE TO PRODUCE LIGHT PRECIP TONIGHT IN THE FAVORED AREAS
NORTH OF THE FRENCH BROAD VALLEY. THE COLD ADVECTION WILL ALLOW
TEMPS TO COOL ENOUGH THAT ICE NUCLEATION COULD OCCUR CLOSE TO THE
SURFACE SO SNOW IS LIKELY...BUT FREEZING DRIZZLE OR RIME ICING COULD
OCCUR INSTEAD. IN LIGHT OF THE CONTINUING WINTER PRECIP ALONG WITH
THE AFOREMENTIONED STRONG WIND GUSTS...BUT LACKING MUCH ADDITIONAL
ACCUMULATION...THE WINTER STORM WARNING IN EFFECT FOR MADISON CO
NORTHWARD TO AVERY CO WILL BE REPLACED WITH A WINTER WX ADVISORY.
THIS WILL ENCOMPASS THE VARIOUS THREATS...INCLUDING UNCOMFORTABLY
COLD WIND CHILLS. FOR LOW TEMPS...CHOSE TO FOLLOW BIAS CORRECTED GFS
MOS WHICH HAS PERFORMED WELL WITH SIMILAR WX CONDITIONS LATELY.
THE NORTHWEST FLOW SHOULD RELAX IN INTENSITY LATE TONIGHT AS THE SFC
HIGH PUSHES OVERHEAD AND FLOW TURNS MORE WESTERLY AT MID-UPPER
LEVELS...WITH SW WINDS IN THE LOW LEVELS. CIRRUS ARE EXPECTED TO
SPREAD OVER AS UPPER MOISTURE INCREASES AHEAD OF NEXT SYSTEM. TEMPS
WILL REBOUND TO NEAR NORMAL.
&&
.SHORT TERM /MONDAY NIGHT THROUGH WEDNESDAY/...
AS OF 145 PM SUNDAY...THE MAIN STORY OF THE SHORT TERM WILL BE THE
PATTERN TRANSITION FROM BROAD EASTERN TROUGHING TO A FAST QUASI-
ZONAL FLOW BY THE END OF PERIOD. IN THE INTERIM...YET ANOTHER UPPER
DISTURBANCE WILL APPROACH THE AREA WITHIN NW FLOW MONDAY EVENING...
WITH ANOTHER ROUND OF MOISTURE IMPACTING THE WESTERN NC MTNS AFTER
MIDNIGHT. THE GFS REMAINS VERY STINGY WITH QPF...WHILE THE NAM
SQUEEZES OUT A COUPLE OF TENTHS OF AN INCH ACROSS THE TENNESSEE
BORDER AREAS THROUGH TUESDAY MORNING. BASED UPON ENSEMBLE
GUIDANCE...AS WELL AS THE FACT THAT THE GFS SEEMS TO BE TRENDING
SLOWLY TOWARD A SLIGHTLY WETTER SOLUTION...POPS HAVE BEEN INCREASED
TO 40-50 PERCENT ALONG MUCH OF THE TENN BORDER. NEVERTHELESS...OTHER
THAN THE PERSISTENT UPSLOPE FLOW...IT APPEARS THAT FORCING WILL BE
VERY LIMITED...SO QPF SHOULD BE FAIRLY LIGHT. P-TYPE IS NOT
PARTICULARLY CLEAR CUT...AS THE COOL AIR MASS CONTINUES TO MODIFY
OVER THE AREA. IT DOES APPEAR THAT SNOW WILL BE THE MOST LIKELY
P-TYPE...WITH A POSSIBLE TRANSITION TO RAIN BY TUESDAY MORNING...AS
THE ATMOSPHERE DRIES OUT FROM ABOVE. SOME POCKETS OF FREEZING RAIN
WILL BE POSSIBLE WHERE COLD AIR IS TRAPPED IN SHELTERED VALLEYS. AS
FOR THE REMAINDER OF THE AREA...THE SHORT TERM MODELS APPEAR TO BE
REACHING A CONSENSUS THAT PRECIP ASSOCIATED WITH WEAK SURFACE WAVE
DEVELOPMENT TO OUR SOUTHWEST WILL REMAIN WELL SOUTH OF THE FORECAST
AREA.
WITH RISING HEIGHTS ALOFT...TEMPERATURES WILL WARM TO ABOVE CLIMO BY
THE END OF THE PERIOD...WITH MANY AREAS ACROSS THE PIEDMONT LIKELY
HITTING THE 60 DEGREE MARK BY WEDNESDAY AFTERNOON.
&&
.LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY/...
AS OF 145 PM SUNDAY...CONFIDENCE IN THE UPPER PATTERN IS ABOUT
AVERAGE IN THE MEDIUM RANGE...BUT BELOW AVERAGE IN THE FCST DETAILS.
A SPLIT FLOW IN THE WEST AND CONFLUENT NWLY FLOW IN THE EAST WILL
TRANSITION BACK TO A DEEP WESTERN TROF AND AN AMPLIFYING EASTERN
RIDGE OVER THE WEEKEND.
THE MEDIUM RANGE STARTS OUT WITH SFC HIGH PRES CENTERED OVER THE ST.
LAWRENCE VALLEY...WITH A WEDGE DOWN THE EAST SIDE OF THE
APPALACHIANS WEDNESDAY NIGHT. AS THE PATTERN CHANGES...A FAIRLY
STRONG SHORTWAVE TROF WILL CROSS THE GREAT LAKES THURSDAY...WITH A
WEAKER SOUTHERN STREAM TROF ACRS THE LOWER MS VALLEY. THERE IS
UNCERTAINTY ON HOW MUCH MOISTURE THESE SYSTEMS WILL PICK UP AS THEY
CROSS THE APPALACHIANS/CWFA THURSDAY NIGHT INTO FRIDAY. THE 12Z GFS
HAS COME IN WETTER WITH A STRONGER SOUTHERN SYSTEM. HOWEVER...I WILL
STICK WITH THE SLGT CHC POPS OF HPC FOR NOW...GIVEN THE UNCERTAINTY.
I WILL NOTE THAT THE LAST FEW SYSTEMS HAVE SEEMED TO VERIFY WETTER
THAN THEY WERE DEPICTED...EVEN JUST A COUPLE DAYS OUT. SO POPS MAY
TREND UP IN THE NEXT FEW CYCLES DURING THIS PERIOD...IF MODELS
CONVERGE ON A SOLN. AS I WRITE THIS...THE 12Z ECMWF HAS COME IN
STUBBORNLY HOLDING ONTO A NOREASTER SIMILAR TO THE 00Z RUN FOR
FRIDAY. FORTUNATELY...THICKNESSES IN BOTH THE ECWMF AND GFS LOOK TO
SUPPORT PRIMARILY LIQUID PRECIP ACRS THE REGION.
BEHIND THAT SYSTEM...ANOTHER SFC HIGH SETTLES INTO SE CANADA AND THE
NE STATES FRIDAY NIGHT THRU SUNDAY...RESULTING IN ANOTHER WEDGE. THE
WEDGE LOOKS DRY ON THE GFS...BUT WETTER ON THE GEFS ENSEMBLE (AND
THAT GOES FOR THE THURSDAY SYSTEM TOO). GIVEN THE UPPER RIDGE AXIS
OVER THE AREA SATURDAY AND SUNDAY...I WILL UNDERCUT THE HPC POPS
UNTIL LATE SUNDAY WITH THE RETURN FLOW...AS SFC RIDGE SHIFTS OFF THE
EAST COAST. TEMPS ARE MOST UNCERTAIN THURSDAY AND FRIDAY...DUE TO
COLD AIR DAMMING AND POP UNCERTAINTY. GUIDANCE HAS TEMPS WARMING TO
ABOVE NORMAL FOR THE WEEKEND (BUT COLD AIR DAMMING ON SATURDAY MAY
NEGATE THE EFFECTS OF RISING HEIGHTS ALOFT).
&&
.AVIATION /00Z MONDAY THROUGH FRIDAY/...
AT KCLT...NW WINDS WILL CONTINUE THROUGH THE NIGHT..THOUGH SPEEDS
WILL BECOME LIGHT BY MIDNIGHT. WINDS WILL TURN OUT OF THE SOUTHWEST
BY LATE MORNING AND INCREASE TO 7 TO 8 KTS BY LATE AFTN. IN
FACT...THAT MIGHT BE A LITTLE LOW AS THE NAM BUFKIT SOUNDINGS IMPLY
SPEEDS MAY BE CLOSER TO 10KTS WILL GUSTS UP TO 18 TO 20 KTS. I
DIDN/T GO THAT HIGH AS HIGH CLOUDS WILL BE FAIRLY DENSE BY LATE AFTN
WHICH SHOULD KEEP DOWN THE MIXING A LITTLE.
ELSEWHERE...WNW TO NW WINDS WILL GUST UP TO 20 KTS FOR A COUPLE MORE
HOURS. OVER THE FOOTHILLS AND PIEDMONT...THEN BECOME LIGHT
OVERNIGHT. KAVL WILL SEE STRONGER GUSTS THROUGH LATE EVENING BEFORE
THE WINDS START TO LET UP. WINDS WILL SHIFT OUT OF THE SW BY LATE
MORNING MONDAY...INCREASING TO AROUND 8 KTS AT MOST SITES BY MID
AFTN. HIGH CLOUD WILL GRADUALLY THICKEN THROUGH THE PERIOD.
OUTLOOK...SOME LIGHT WINTRY WEATHER MAY AFFECT KAVL MONDAY NIGHT.
OTHERWISE FAIR WEATHER THROUGH LATE WEEK.
AN EXPERIMENTAL AVIATION FORECAST CONSISTENCY TABLE SHOWING THE
PERCENTAGE OF GUIDANCE MEMBERS AGREEING WITH THE SCHEDULED ISSUANCE
CATEGORY IS AVAILABLE AT THE FOLLOWING LINK (USE LOWER CASE)...
WWW.WEATHER.GOV/GSP/AVIATION_TABLES
&&
.FIRE WEATHER...
WINDS ARE GUSTING AS HIGH AS 30 MPH THIS AFTERNOON ACROSS THE
UPSTATE...PARTICULARLY OVER THE WESTERN HALF OF THE AREA. 10-HOUR
FUEL MOISTURE LEVELS ARE GENERALLY LESS THAN 10 PERCENT.
FORTUNATELY...RH REMAINS ABOVE 35 PERCENT ACROSS MOST OF THE AREA.
THE FIRE DANGER STATEMENT WILL REMAIN IN EFFECT FOR THE UPSTATE
UNTIL 7 PM.
&&
.GSP WATCHES/WARNINGS/ADVISORIES...
GA...NONE.
NC...WIND ADVISORY UNTIL 1 AM EST MONDAY FOR NCZ052-053-059-062-063-
501-503-505.
WINTER WEATHER ADVISORY UNTIL 1 AM EST MONDAY FOR NCZ033-
048>050.
SC...NONE.
&&
$$
SYNOPSIS...SBK
NEAR TERM...MCAVOY/WIMBERLEY
SHORT TERM...JDL
LONG TERM...ARK
AVIATION...MCAVOY
FIRE WEATHER...
AREA FORECAST DISCUSSION
NWS HOUSTON/GALVESTON TX
336 PM CST SAT FEB 2 2013
.DISCUSSION...
VERY WEAK FRONTAL BOUNDARY SHOULD MAKE ITS WAY TO THE I-10
CORRIDOR AROUND MIDNIGHT THEN OFFSHORE BEFORE SUNRISE. MAY SEE
SOME AREAS OF FOG CLOSER TO THE COAST BEFORE FROPA. OFFSHORE
WINDS WILL BE SHORT LIVED AS SE FLOW WILL RESUME BY EVENING WHEN
SFC HIGH PUSHES OFF TO THE EAST.
THESE ONSHORE WINDS WILL TRANSPORT SOME 1.3"-1.5" PW`S BACK INTO
THE AREA ON MONDAY COINCIDING WITH SOME WEAK IMPULSES MOVING
OVERHEAD. ANTICIPATE SOME SCT SHRA TO DEVELOP ACROSS THE REGION
WITH THE HIGHEST CHANCES PROBABLY E OF I-45.
APPEARS ANOTHER REALLY WEAK FRONT WILL APPROACH THE COAST ON TUES. LOOKS
LIKE IT`LL STALL JUST INLAND. GFS/ECMWF IN FAIR AGREEMENT SHOWING
UPPER TROF (CURRENTLY SEEN ON W/V IMAGERY OFF THE NRN CALIFORNIA
COAST) DROPPING SOUTH THEN EAST ACROSS S TX TUES NIGHT & WED.
THIS SHOULD PROVIDE OUR NEXT SHOT OF RAINFALL...ESPECIALLY THE SRN
HALF OF SE TX AND OFFSHORE. NUDGED POPS UPWARD DURING THIS TIME
PERIOD - AND WILL PROBABLY NEED TO CONTINUE DOING SO IF FUTURE
MODEL RUNS ARE CONSISTENT.
THE NEXT WRN TROF MAKES ITS WAY EWD NEXT WEEKEND. STILL SOME
TIMING/PATTERN DIFFERENCES BUT MEDIUM RANGE GUESSES BRING THE NEXT
COLD FRONT AND ASSOCIATED PRECIP INTO THE REGION NEXT SUNDAY...BUT
MAY SEE SOME SCT ACTIVITY IN ADVANCE ON SAT. 47
&&
.MARINE...
THE WEAK COLD FRONT SHOULD WORK ITS WAY OFF THE COAST BY AROUND 6 AM
SUNDAY. DO NOT THINK SEA FOG WILL FORM AS THE SURFACE DEWPOINTS
SHOULD STAY BELOW THE WATER TEMPERATURES. OTHERWISE...ONSHORE WINDS
WILL QUICKLY RETURN AHEAD OF THE NEXT FRONT TO MOVE OFF THE COAST
EARLY TUESDAY. MODERATE ONSHORE FLOW MAY DEVELOP BY AROUND MID WEEK
AS THE MODELS ARE SHOWING AN INCREASED PRESSURE GRADIENT. 40
&&
.147 PM AVIATION...
VFR CONDITIONS WILL PERSIST THROUGH THIS EVENING. A WEAK FRONT IS
FORECAST TO PUSH THROUGH TO THE COAST BY AROUND SUNRISE SUNDAY.
THERE IS A CHANCE THAT FOG WILL DEVELOP AHEAD OF THE FRONT...
ESPECIALLY FROM KCXO TO THE COAST. THE LATEST MODELS ARE A BIT
FASTER WITH THE FRONT PUSHING OUT THE FOG THAN THE 18Z FORECAST
INDICATES. WILL COMPARE THE LATEST RAP MODEL FORECASTS AND MAKE
ADJUSTMENTS ON THE 21Z UPDATE IF NEEDED. 40
&&
.PRELIMINARY POINT TEMPS/POPS...
COLLEGE STATION (CLL) 44 70 50 72 53 / 0 0 10 30 20
HOUSTON (IAH) 49 72 52 74 56 / 0 0 0 30 30
GALVESTON (GLS) 56 68 60 70 60 / 0 0 0 20 40
&&
.HGX WATCHES/WARNINGS/ADVISORIES...
TX...NONE.
GM...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS HOUSTON/GALVESTON TX
147 PM CST SAT FEB 2 2013
.DISCUSSION...
SEE THE 18Z/21Z AVIATION DISCUSSION BELOW.
40
&&
.AVIATION...
VFR CONDITIONS WILL PERSIST THROUGH THIS EVENING. A WEAK FRONT IS
FORECAST TO PUSH THROUGH TO THE COAST BY AROUND SUNRISE SUNDAY.
THERE IS A CHANCE THAT FOG WILL DEVELOP AHEAD OF THE FRONT...
ESPECIALLY FROM KCXO TO THE COAST. THE LATEST MODELS ARE A BIT
FASTER WITH THE FRONT PUSHING OUT THE FOG THAN THE 18Z FORECAST
INDICATES. WILL COMPARE THE LATEST RAP MODEL FORECASTS AND MAKE
ADJUSTMENTS ON THE 21Z UPDATE IF NEEDED.
40
&&
.PREV DISCUSSION... /ISSUED 952 AM CST SAT FEB 2 2013/
DISCUSSION...
SHOULD SEE A NICE WARM UP THIS AFTN WITH HIGHS TOPPING OUT IN THE
70S. CURRENT FCST IS IN GOOD SHAPE. JUST SOME INSIGNIFICANT TWEAKS
TO THE GRIDS BASED ON LATEST TRENDS FOR THE MORNING UPDATE. 47
&&
.PRELIMINARY POINT TEMPS/POPS...
COLLEGE STATION (CLL) 74 43 69 50 72 / 0 10 0 20 30
HOUSTON (IAH) 75 48 71 51 74 / 0 10 0 10 30
GALVESTON (GLS) 71 55 68 57 68 / 0 10 0 10 20
&&
.HGX WATCHES/WARNINGS/ADVISORIES...
TX...NONE.
GM...NONE.
&&
$$
DISCUSSION...47
AVIATION/MARINE...40
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
535 PM CST SUN FEB 3 2013
.SHORT TERM...TONIGHT THROUGH WEDNESDAY NIGHT
230 PM CST SUN FEB 3 2013
SNOW SNOW AND MORE SNOW. IMPULSES CONTINUE TO MOVE ALONG THE
NORTHWEST FLOW...BRINGING LIGHT SNOW ON A NEARLY EVERYDAY BASIS.
LATEST 88-D IMAGERY AND SFC OBS INDICATE A FRONTOGENETIC BAND OF
LIGHT SNOW MOVING ACROSS SOUTHEAST MN...TRACKING SOUTHEAST TOWARD
NORTHEAST IA/SOUTHWEST WI. THE HRRR IS DOING A DECENT JOB CAPTURING
THIS...ABOUT THE ONLY MESO MODEL THAT IS. IT IS NOT PART OF THE
MAIN SYSTEM AT THE MOMENT...WHICH WILL MOVE IN EARLY THIS EVENING.
STILL...THIS LIGHT SNOW COULD RESULT IN TRACE-COUPLE TENTHS OF AN
INCH OF ACCUMULATION AS IT MOVES ACROSS.
A BAND OF SNOW WILL SLIDE EAST/SOUTHEAST ACROSS THE FORECAST AREA
TONIGHT...AS AN UPPER LEVEL SHORTWAVE TROUGH DRIVES FROM THE
NORTHERN PLAINS TO ACROSS IA BY MONDAY MORNING. RELATIVELY STRONG
SLOPING FRONTOGENETIC RESPONSE ON THE NORTH SIDE OF THE TROUGH/SFC
LOW...WITH SOME -EPV ON THE SOUTHERN PORTIONS OF THIS
LIFT...SUGGESTING THE POTENTIAL FOR ENHANCED BANDING. STRONG 275-290
K ISENTROPIC UPGLIDE WITH A GOOD PUNCH OF QG CONVERGENCE -
ESPECIALLY IN THE 850:700 MB LAYER. MESO MODELS AND NAM/GFS/EC ALL
SUGGEST THERE IS GOING TO BE A NARROW BAND OR SNOW WITH THIS
SYSTEM...
MOSTLY IN THE FRONTOGENETIC REGION. THIS HAS BEEN A CONSISTENT
SIGNAL. NORTH-SOUTH RUNNING TIME/HEIGHT X-SECTIONS SUGGEST THE
DEEPER DENDRITIC GROWTH ZONE WILL BE NORTH OF A RST-KLSE LINE...AWAY
FROM THE STRONGEST LIFT. THE STRONGER LIFT AND POTENTIAL FOR
ENHANCED BANDING COULD OFFSET THE RELATIVELY LOWER RATIOS IN THE
SOUTH. THAT SAID...OVERALL A 20-25:1 RATIO LOOKS REASONABLE...AND
PUTS 3 TO 4 INCHES IN THE FAVORED SNOW AREAS. ISOLATED 5 INCH
AMOUNTS ARE POSSIBLE. EXPANDED THE ADVISORY THIS MORNING...AND WILL
LEAVE AS CURRENTLY CONFIGURED FOR TONIGHT.
WITH A LOT OF PEOPLE OUT AT SUPERBOWL PARTIES...THERE WILL BE A
SIGNIFICANT AMOUNT OF TRAFFIC LATER THIS EVENING. SNOW WILL BE
FALLING AND THERE WILL BE ACCUMULATIONS ON ROADWAYS. CONDITIONS WILL
DETERIORATE AS THE EVENING WEARS ON. THE MORNING COMMUTE WILL ALSO
BE IMPACTED.
MONDAY NIGHT/TUESDAY MORNING DROPS ANOTHER SHORTWAVE TROUGH ACROSS
THE REGION...BUT THIS GO AROUND THE 03.12Z GFS AND NAM FAVOR A BIT
MORE NORTHERN TRACK. FAIRLY CONSISTENT WITH THEIR PREVIOUS RUNS.
DECENT AMOUNT OF QG CONVERGENCE WITH THE SHORTWAVE...ALONG WITH
UPGLIDE ON THE 280-295 K ISENTROPIC SFCS. SOME WEAK FRONTOGENETIC
RESPONSE IN THE 900-800MB ON THE LEADING EDGE OF THE SHORTWAVE. NOT
NEARLY AS DYNAMIC AS THE SYSTEM FOR TONIGHT...BUT PACKS ENOUGH OF A
PUNCH FOR ANOTHER ROUND OF LIGHT SNOW WITH MINOR ACCUMULATIONS.
NAM/GFS BUFKIT SOUNDINGS DON/T INDICATE A VERY DEEP DENDRITIC GROWTH
REGION...WHICH WILL HELP KEEP RATIOS LOWER...AND THUS SNOW AMOUNTS.
15:1 SEEMS REASONABLE AT THIS TIME...WHICH WOULD RESULT IN ABOUT 1-2
INCHES OF ACCUMULATION...MORE LIKELY NORTH/EAST OF THE I-94
CORRIDOR. WHILE AN ADVISORY SHOULD NOT BE NEEDED WITH THIS
SYSTEM...TIMING WOULD RESULT IN LIGHT SNOW FALLING DURING THE
MORNING RUSH.
FINALLY...THE CABOOSE FOR THIS TRAIN OF NORTHWEST SHORTWAVES ARRIVES
WED NIGHT...WITH AGAIN GOOD CONTINUITY BETWEEN THE GFS AND NAM.
COULD BE A COUPLE SHORTWAVES WORKING IN CONCERT DURING THIS
PERIOD...ALONG WITH AN ELEMENT OF MOISTURE RETURN/SOUTHERLY FLOW
AHEAD OF IT. THE GFS AND ECMWF SUGGEST THIS...DEVELOPING QPF IN THIS
REGION...ALONG AN ASSOCIATED SFC FRONT. SNOW RATIOS LOOK MORE IN
THE 15:1 RATIO...AND THE SYSTEM MOVES THROUGH PRETTY QUICK. DON/T
ANTICIPATE MUCH ACCUMULATION AT THIS TIME...GENERALLY UNDER AN
INCH.
.LONG TERM...THURSDAY THROUGH SUNDAY
230 PM CST SUN FEB 3 2013
FINALLY...A BREAK FROM THE NEARLY DAILY SNOW WITH HIGH PRESSURE
BUILDING IN THU NIGHT/FRI. ITS A SHORT LIVED BREAK THOUGH AS THE GFS
AND ECMWF BOTH BRING A STORM SYSTEM OUT OF THE SOUTHWEST AND ACROSS
THE REGION FOR THE WEEKEND. DIFFERENCES CONTINUE WITH THE
STRENGTH...SPEED...AND PLACEMENT OF THE SYSTEM...WHICH ALSO IMPACTS
AMOUNTS. PTYPE WILL ALSO BE A CONCERN AS THERE WILL BE A GOOD SURGE
OF WARMER AIR ON THE EASTERN SIDE OF THE LOW. THE GFS IS THE MORE
AGGRESSIVE WITH ITS AMOUNT OF MOISTURE/QPF AND WARMING. IT HAS A LOT
MORE QPF...ESPECIALLY OUT AHEAD OF THE LOW IN THE MOISTURE
TRANSPORT/WARM AIR ADVECTIVE REGION. BOTH AGREE THERE WILL BE A
DEFORMATION REGION OF SNOW TO THE NORTHWEST OF THE LOW...WITH
SIGNIFICANT AMOUNTS. IT WOULDN/T BE THE FLUFFY...EASY TO MOVE SNOW
EITHER. ITS DEFINITELY A STORM THAT BEARS A CLOSE WATCH.
&&
.AVIATION...TONIGHT AND MONDAY
535 PM CST SUN FEB 3 2013
SURFACE LOW PRESSURE WAS LOCATED OVER CENTRAL SOUTH DAKOTA LATE
THIS AFTERNOON WITH A WARM FRONT BISECTING IOWA FROM NORTHWEST TO
SOUTHEAST. LIGHT SNOW IS STARTING TO DEVELOP NORTH OF THE WARM
FRONT AND LOW OVER WEST CENTRAL MINNESOTA INTO NORTH DAKOTA. THE
03.18Z NAM HAS REMAINED CONSISTENT IN SHOWING THE SURFACE LOW
MOVING ALONG THE FRONT TONIGHT AND AS IT APPROACHES THE AREA...THE
LOW LEVEL FORCING WILL BE STRENGTHENING. A BAND OF WEAK TO
MODERATE FRONTOGENESIS WILL SET UP OVER THE AREA IN THE 850-500 MB
LAYER AND SHOULD BE THE STRONGEST IN THE 700-750 MB LAYER WHERE A
BAND OF FN VECTOR CONVERGENCE WILL ALSO OCCUR. AN AREA OF
ISENTROPIC UP GLIDE WILL BE IN PLACE UP AND OVER THE WARM FRONT
WITH 2 TO 4 UBAR/S OVER THE SOUTHWEST HALF OF THE FORECAST AREA.
AS THE SHORT WAVE TROUGH APPROACHES...IT IS EXPECTED TO PRODUCE
BETWEEN 16 AND 24 PVU/S OF UP GLIDE IN THE 500-300 MB LAYER. THIS
FORCING WILL COMBINE WITH THE LOW LEVEL FORCING TO PRODUCE ANOTHER
BAND OF SNOW OVER BOTH TAF SITES. EXPECT THIS BAND TO DEVELOP/MOVE
IN BY THE MIDDLE OF THE EVENING. INITIALLY EXPECTING MVFR
CONDITIONS...BUT THE VISIBILITY SHOULD QUICKLY GO DOWN TO IFR AND
REMAIN THERE FOR ABOUT A 4 TO 5 HOUR PERIOD BEFORE IT EXITS
ALLOWING THE RETURN OF MVFR CONDITIONS. THE SNOW SHOULD TOTALLY
END BEFORE 12Z AND AS HIGH PRESSURE AND DRIER AIR MOVES IN MONDAY
MORNING...THE CLOUDS ARE EXPECTED TO SCATTER OUT FOR VFR
CONDITIONS MUCH OF THE DAY.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
230 PM CST SUN FEB 3 2013
WI...WINTER WEATHER ADVISORY FROM 6 PM THIS EVENING TO 8 AM CST
MONDAY FOR WIZ032-033-041-042-053>055-061.
MN...WINTER WEATHER ADVISORY FROM 6 PM THIS EVENING TO 8 AM CST
MONDAY FOR MNZ079-086>088-094>096.
IA...WINTER WEATHER ADVISORY FROM 6 PM THIS EVENING TO 8 AM CST
MONDAY FOR IAZ009>011-030.
&&
$$
SHORT TERM...RIECK
LONG TERM....RIECK
AVIATION...04
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
230 PM CST SAT FEB 2 2013
.SHORT TERM...TONIGHT THROUGH TUESDAY NIGHT
230 PM CST SAT FEB 2 2013
THE TRAIN OF NORTHWEST FLOW SHORTWAVES CONTINUES.
TONIGHT...AN UPPER LEVEL SHORTWAVE CURRENTLY MIGRATING ACROSS THE
NORTHERN PLAINS WILL SLIDE ACROSS THE REGION. SOME WEAK 2-D
FRONTOGENETIC RESPONSE AT 900 MB WITH THE FEATURE...ALONG WITH WEAK
QG CONVERGENCE THROUGH THE 850-300 MB LAYER. SOME ISENTROPIC UPGLIDE
ON THE 280-290 K SFCS THIS EVENING...MOST OF WHICH EXITS EAST AFTER
06Z. GOOD DENDRITIC ZONE GROWTH //DGZ// REGION THOUGH...FROM 700 MB
TO THE SFC FOR MUCH OF TONIGHT...WHEN THE SNOW WILL BE FALLING.
RATIOS OF 30:1 ARE REASONABLE GIVEN THIS SCENARIO. THIS SHORTWAVE
DOESN/T LOOK TO BE AS PERKY AS THE ONE LAST NIGHT...AND WILL HAVE
EVEN LESS QPF. SO...EXPECT LESS SNOWFALL AMOUNTS. SOME CONCERN THAT
IT MIGHT MISS A BULK OF THE FORECAST AREA...WITH LATEST HRRR AND ARW
MESO MODELS SUGGESTING THAT MOST OF THE ACCUMULATING SNOWS WILL MOVE
INTO CENTRAL IA. THE NAM12/GFS40 SHOW SOMETHING SIMILAR...BUT STILL
PAINT SOME LIGHT SNOW INTO NORTHERN WI. WILL TREND THE HIGHER POPS
TO THE SOUTH.
SHORTWAVE NUMBER 4 SPINS ACROSS IA SUNDAY NIGHT...EXITING OVER THE
OH RIVER VALLEY ON MONDAY. FRONTOGENETIC RESPONSE IS MUCH STRONGER
WITH THIS FEATURE...AS IS THE QG CONVERGENCE AND ISENTROPIC UPGLIDE.
THE DGZ ISN/T AS DEEP AS EXPECTED FOR TONIGHT...AND WITH PREVIOUS
SHORTWAVES. THIS WILL HELP KEEP RATIOS CLOSER TO 15/20:1.
NAM/GFS/ECMWF ALL COMPARABLE WITH PRODUCING A RELATIVELY NARROW BAND
OF QPF...FOCUSED ON THE FRONTOGENETIC REGION...AND CENTER IT ROUGHLY
AROUND A ROCHESTER TO RICHLAND CENTER LINE. SEE THE POTENTIAL FOR
SOME ADVISORY AMOUNTS IN THE BAND...3 TO 4 INCHES POSSIBLE. NOT
ENOUGH CONFIDENCE TO ISSUE AT THIS TIME...BUT SCENARIO WILL CONTINUE
TO EVALUATED.
COME TUE...SURPRISE...SHORTWAVE NUMBER 5 DROPS FROM CANADA TO ACROSS
NORTHERN PARTS OF MN/WI. GFS AND NAM BOTH AGREE ON A SLIGHTLY MORE
NORTHERLY TRACK TO THIS WEATHER FEATURE...BRINGING THE BETTER SNOW
CHANCES TO NORTHERN PARTS OF THE FORECAST AREA. ANOTHER
INCH...PERHAPS TWO...LOOKS LIKELY.
.LONG TERM...WEDNESDAY THROUGH SATURDAY
230 PM CST SAT FEB 2 2013
VERY ACTIVE NORTHWEST FLOW CONTINUES THROUGH THE END OF THE WORK
WEEK. HOWEVER...WE MIGHT SEE THE CABOOSE WED NIGHT/THU
MORNING...WITH THE EC AND GFS SPINNING A PIECE OF UPPER LEVEL ENERGY
ACROSS THE REGION WED NIGHT...REINFORCED BY A STRONGER SHORTWAVE THU
MORNING. SOME QUESTION ON PTYPES WITH THIS EVENT AS WARMER AIR WILL
BE RETURNING...AND A POSSIBLE LOSS OF ICE IN THE CLOUD AS THE SYSTEM
STARTS TO EXIT EAST. WON/T GET OVERLY DETAILED WITH GRIDS AT THE
MOMENT...BUT THE POTENTIAL FOR MIXED WINTER PCPN WILL HAVE TO BE
MONITORED.
THE GFS AND EC FAVOR BRINGING A LOW PRESSURE SYSTEM OUT OF THE SOUTH
FOR THE WEEKEND...DRIVING IT ACROSS THE REGION SAT/SUN. DIFFERENCING
IN STRENGTH AND POSITION...AND SOME VARIANCE IN TIMING. BOTH WOULD
LAY DOWN A DEFORMATION BAND OF SNOW...BUT ALSO LIKELY HAVE SOME
RAIN/WINTER MIX ON ITS SOUTHEAST SIDE. THIS SYSTEM ALSO LOOKS TO
PACK MUCH MORE OF A PUNCH THAN THE PARADE OF SHORTWAVES MOVING DOWN
FROM THE NORTHWEST.
&&
.AVIATION...
1146 AM CST SAT FEB 2 2013
THIS AFTERNOON...MID CLOUDS /8 TO 10K/ WILL BE ON THE INCREASE AND
THE LIGHT SURFACE WINDS WILL GRADUALLY SHIFT FROM THE NORTHWEST TO
THE SOUTH AS YET ANOTHER SHORTWAVE MOVES THROUGH THE REGION.
TONIGHT...THE SHORTWAVE TROUGH WILL MOVE THROUGH THE REGION. AT THIS
TIME IS LOOKS LIKE THE BEST LIFT WILL OCCUR BETWEEN 03.02Z AND
03.07Z AT KRST AND BETWEEN 03.04Z AND 03.08Z AT KLSE. IN
ADDITION...THIS LIFT IS CO-LOCATED WITH A 8K FOOT DENDRITIC GROWTH
ZONE. THIS WILL RESULT IN ANOTHER ROUND OF SNOW FOR THE AREA.
VISIBILITIES WILL QUICKLY DROP TO 1 1/2 MILES DURING THIS TIME
PERIOD AND THE CEILINGS WILL BECOME MVFR. SNOW AMOUNTS WILL BE
AROUND AN INCH.
SUNDAY...SUBSIDENCE WILL CAUSE THE SKIES TO GRADUALLY CLEAR
BETWEEN 03.12Z AND 03.16Z.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
230 PM CST SAT FEB 2 2013
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
SHORT TERM...RIECK
LONG TERM....RIECK
AVIATION.....BOYNE
AREA FORECAST DISCUSSION...UPDATED
NWS MILWAUKEE/SULLIVAN WI
1153 AM CST SAT FEB 2 2013
.UPDATE...VIS SAT SHOWS SKIES CLEARING ACROSS NORTHERN PORTIONS OF
THE FORECAST AREA...WITH THE BACK EDGE OF THE LOW LEVEL CLOUDS
WORKING ITS WAY SOUTH. UPDATED SKY GRIDS TO REFLECT LATEST
TRENDS. BOTH RAP AND NAM BUFKIT MODEL SOUNDINGS REFLECT SUCH A
TREND...AND HAVE THE LOW LEVELS OF THE MODEL SOUNDINGS DRYING OUT.
FURTHER...THE MODEL RH FIELDS...ESPECIALLY AT 850 HPA...SHOW A
DECREASING RH TREND.
FOR LATER IN THE DAY...NAM12 AND RAP BOTH SHOW AN INCREASE IN
MID- AND UPPER-LEVEL RH...THAT COINCIDES WITH CLOUDS SEEN ACROSS
EASTERN MN INTO SOUTHWESTERN WISCONSIN. THESE CLOUDS ARE EXPECTED
TO CONTINUE TO WORK THEIR WAY INTO SOUTH CENTRAL AND SOUTHEAST WI
THIS AFTERNOON.
TEMPERATURES WERE UPDATED TO REFLECT LATEST TRENDS. GIVEN THE
BREAK IN THE CLOUDS THAT WASNT EXACTLY ANTICIPATED IN THE
FCST...NOW CONCERNED WITH THE IMPACT LESS SKY COVER WILL HAVE ON
HIGH TEMPS. HOWEVER...THERE IS LIGHT COLD AIR ADVECTION ONGOING ON
THE LOW LEVELS. TEMPERATURE FCST IS TRENDING OK SO FAR...SO WILL
WAIT A BIT AND WILL EVALUATE MORE OF SHORT TERM GUIDANCE AND
ADJUST IF NEEDED.
ET
&&
.AVIATION/18Z TAFS/...VFR CONDITIONS EXPECTED ACROSS TAF SITES
THIS AFTERNOON AND EVENING. WINDS WILL BACK FROM NORTH THIS
AFTERNOON TO SOUTHWEST BY 06Z SUNDAY...REMAINING LIGHT. LOW CLOUDS
WILL MOVE SOUTH OF THE AREA EARLY THIS AFTERNOON...WITH MID TO
HIGH CLOUDS GRADUALLY FILLING INTO THE AREA THROUGH THE AFTERNOON
AND EVENING.
MVFR CEILINGS WITH VERY LIGHT SNOW IS EXPECTED BETWEEN 06Z AND 12Z
SUNDAY AT MADISON...AND 09Z AND 15Z SUNDAY AT THE EASTERN TAF
SITES. THE VERY LIGHT SNOW MAY BE ON AND OFF...AND ANY
ACCUMULATIONS WOULD BE 0.1 TO 0.2 INCHES AT BEST. FLUFFY AND
POWDERY SNOW IS EXPECTED...BUT STILL WOULD BE AN IMPACT ON
RUNWAYS.
WINDS VEER NORTHWEST BETWEEN 12Z AND 15Z SUNDAY AND BECOME GUSTY
THROUGH THE DAY. GUSTS TO 23 KNOTS ARE EXPECTED.
WOOD
&&
.PREV DISCUSSION... /ISSUED 344 AM CST SAT FEB 2 2013/
SHORT TERM...
TODAY AND TONIGHT...FORECAST CONFIDENCE - MEDIUM.
ENHANCED FORCING FROM WARM AIR ADVECTION SLIDING OFF TO THE
SOUTHEAST EARLY THIS MORNING RESULTING IN DIMINISHING ACCUMULATING
SNOW. HOWEVER...AREAS OF VERY LIGHT SNOW LAGGING BEHIND ASSOCIATED
WITH WEAK 85H TROUGH WHICH PASSES THRU SRN WI MAY RESULT IN AN
ADDITIONAL DUSTING BTWN 12Z AND 15Z. CLOUDS SHOULD THIN LATER TODAY
ALLOWING SOME SUNSHINE TO RETURN FOR A TIME. HOWEVER CLEARING WL BE
SHORT-LIVED AS ANOTHER WEAKER PUSH OF WARM AIR ADVECTION WL SWEEP
THROUGH WI TNGT.
WATER VAPOR IMAGERY CLEARLY SHOWS UPSTREAM SHORT WAVE TROUGH OVER
SRN SASKATCHEWAN MOVING SOUTHEAST. APPEARS SHORT TERM GUIDANCE
HAVING DIFFICULTY WITH THIS WAVE BUT IF IT MAINTAINS ITS CURRENT
SOUTHEAST COURSE...WOULD AFFECT PORTIONS OF SOUTHEAST WI OVERNIGHT.
POSSIBLE HINTS FROM Q-VECTOR CONVERGENCE WHERE AXIS OF -5 TO -10
UNITS MOVES ACROSS SRN WI FROM LATE EVE THRU THE OVERNIGHT. LITTLE
FRONTOGENETICAL FORCING...BUT SOME ISENTROPIC OMEGA SHOWING UP ON
280 THETA SFC OVERNIGHT. CONDENSATION PRESSURE DEFICITS DECREASE TO
LESS THAN 10 MB FOR A 3-6 HOUR PD. FOR NOW BUMPED UP TO LIKELY
WORDING ACROSS MORE OF THE NORTH AND WEST...WITH HIGHER CHC
ELSEWHERE. DEEP DENTRITIC GROWTH ZONE WOULD BE TAPPED BY WEAK
FORCING SO SNOW LIQUID RATIOS COULD AGAIN BE HIGHER THAN EXPECTED 25
TO 1. FOR NOW WL KEEP LIGHT ACCUMULATIONS LESS THAN AN INCH IN THE
NORTH AND WEST.
SUNDAY...FORECAST CONFIDENCE HIGH.
STRONG SUBSIDENCE BEHIND THE EXITING 500MB SHORTWAVE EXPECTED TO
BRING SOME SUNSHINE TO SOUTHERN WI DURING THE DAY ON SUNDAY. ONLY
EXPECTING LOWER TO MID TEENS FOR HIGH TEMPS...ALONG WITH COLD WIND
CHILLS WITH WEAK COLD AIR ADVECTION ON BRISK NORTHWEST WINDS.
SUNDAY NIGHT THROUGH MONDAY...FORECAST CONFIDENCE MEDIUM TO HIGH.
THE NEXT SHORTWAVE WILL BRING ANOTHER ROUND OF SNOW TO SOUTHERN WI
SUNDAY NIGHT. INCREASED POPS TO THE DEFINITE CATEGORY AS IMPRESSIVE
700 TO 850MB FRONTOGENESIS AND 700MB OMEGA MOVE ACROSS SOUTHERN
WISCONSIN. THIS WILL PROBABLY BE AN EVENT WHERE A NARROW LINE GETS A
SWATH OF 3 INCHES OF SNOW AND AREAS AROUND IT GET AN INCH. MANY
MODELS FOCUS THE HIGHEST QPF SWATH ACROSS FAR SOUTHERN WI AND
NORTHERN IL. THE CANADIAN HAS THIS SHIFTED SLIGHTLY NORTHWARD. USED
A CONSENSUS FOR SNOW RATIOS IN THE 17 TO 19:1 RANGE. THE 06Z NAM
CAME IN WITH A LATER ARRIVAL/END TIME OF THIS EVENT BY ALMOST 6
HOURS. FAVORED ECMWF TIMING FOR NOW.
SNOW WILL TAPER OFF MONDAY MORNING...ALTHOUGH FLURRIES MAY LINGER
INTO THE AFTERNOON WITH CYCLONIC FLOW ALOFT STICKING AROUND. WEAK
COLD ADVECTION WITH THE SURFACE HIGH MOVING OVERHEAD WILL KEEP TEMPS
COOL ONCE AGAIN...SO HIGHS IN THE UPPER TEENS TO AROUND 20 EXPECTED.
LONG TERM...
TUESDAY...FORECAST CONFIDENCE MEDIUM TO HIGH.
A STRONGER SHORTWAVE TROUGH/VORT MAX ON THE RIGHT ENTRANCE REGION OF
A 110 KNOT UPPER JET WILL ROLL THROUGH THE UPPER MIDWEST ON TUESDAY.
THE ASSOCIATED SURFACE LOW PRESSURE SYSTEM WILL TRACK ACROSS MN AND
WI AS IT WEAKENS AS THE 500MB VORT MAX SHEARS OUT. IT IS BECOMING
MORE LIKELY THAT LIGHT SNOW WILL SPREAD ACROSS SOUTHERN AND CENTRAL
WI EARLY TUE MORNING THROUGH TUE AFTERNOON. SNOW AMOUNTS SHOULD BE
ABOUT 1 TO 2 INCHES.
TUESDAY NIGHT THROUGH FRIDAY...FORECAST CONFIDENCE MEDIUM.
THE FLOW ALOFT WILL TRANSITION TO MORE ZONAL WED AND THU. QUIET
WEATHER EXPECTED ON WEDNESDAY. THEN TEMPS PROGGED TO WARM INTO THE
LOWER 30S ON THU JUST AHEAD OF THE NEXT SHORTWAVE BY THU AFTERNOON.
THE 850MB 0 DEGREE LINE IS FORECAST TO REACH THE WI/IL BORDER...BUT
THE TEMP PROFILE IN FORECAST SOUNDINGS REMAINS BELOW ZERO EXCEPT AT
THE SURFACE. THIS WOULD IMPLY A CHANCE FOR SOME SNOW TO CHANGE OVER
TO RAIN ACROSS SOUTHERN WI LATER THU AFTERNOON IF THE SURFACE WARMS
JUST ENOUGH. KEPT A RAIN/SNOW MIX THERE AND SNOW IN THE NORTHERN
FORECAST AREA.
HIGH PRESSURE AND QUIET WEATHER WITH HIGHS IN THE LOWER 30S WILL BE
IN PLACE FOR FRIDAY. MODELS ARE ADVERTISING A WET SYSTEM APPROACHING
WI OVER THE WEEKEND.
AVIATION/12Z TAFS/...VARYING VSBYS THIS MRNG BTWN MVFR AND VFR AND
-SN DIMINISHES ACROSS SRN WI. MOSTLY VFR CONDITIONS EXPCD THIS AFTN
BEFORE ANOTHER BATCH OF -SN AFFECTS SRN WI TNGT. PERIOD OF -SN WILL
BE BRIEFER THAN THIS MRNG WITH LESS ACCUMULATION.
MARINE...TIGHTENING PRESSURE GRADIENT BEHIND PASSING WEAK LOW
PRESSURE TROUGH MAY RESULT IN WIND GUSTS TO SMALL CRAFT ADVY LEVELS
ON SUNDAY...IN ICE FREE AREAS. THE GUSTY NORTHWEST WINDS WOULD
LINGER INTO SUNDAY EVENING BEFORE DIMINISHING.
&&
.MKX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
LM...NONE.
&&
$$
UPDATE...ET/WOOD
TODAY/TONIGHT AND AVIATION/MARINE...MBK
SUNDAY THROUGH FRIDAY...MRC
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
1126 PM CST FRI FEB 1 2013
.SHORT TERM...TONIGHT THROUGH SUNDAY NIGHT
345 PM CDT FRI FEB 1 2013
AT 3 PM...THE WATER VAPOR IMAGERY SHOWED A SHORT WAVE TROUGH MOVING
SOUTHEAST THROUGH LAKE WINNIPEG. AT THE THE SURFACE...A COLD
FRONT...LOCATED JUST SOUTH OF LAKE WINNE PEG...WAS PRODUCING SNOW
ACROSS THE EASTERN DAKOTAS...AND NORTHWEST AND WEST CENTRAL
MINNESOTA. THIS SNOW WAS REDUCING VISIBILITIES TO 3/4 MILES AT FARGO
NORTH DAKOTA.
FOR TONIGHT...THE 01.12Z MESO AND DETERMINISTIC MODELS ARE IN GOOD
AGREEMENT THAT SHORT WAVE TROUGH AND COLD FRONT TO OUR NORTHWEST
WILL MOVE SOUTHEAST THROUGH THE FORECAST AREA THIS EVENING AND EARLY
OVERNIGHT. MODERATE 270 TO 280K ISENTROPIC LIFT /2 TO 4
MICROBARS/SEC/ DEVELOPS AHEAD OF THIS SYSTEM. THIS IS BRINGING THE
WARMER AND MORE MOIST /DEW POINTS IN THE LOWER AND MID 20S/ AIR
ALOFT. THIS WARMS THE ATMOSPHERIC COLUMN INTO THE DENDRITIC GROWTH
ZONE AND THE MOISTURE SATURATES IT. 01.09Z SREF SHOWS THAT 50 TO
70 PERCENT OF THE ENSEMBLE FAMILY HAS OVER 200 MB OF DENDRITIC
GROWTH THIS EVENING. THE ROCHESTER RAP BUFKIT SOUNDING SHOWS AT
LEAST 10K FEET IN THE DENDRITIC GROWTH ZONE BETWEEN 02.00Z AND
02.06Z. MEANWHILE THE GFS AND NAM BUFKIT SOUNDINGS HAVE A MUCH
SHORTER TIME. THIS WILL AFFECT THE SNOW RATIOS. THE RAP WOULD
SUGGEST 25-30 TO 1 SNOW TO LIQUID RATIOS. MEANWHILE THE GFS AND NAM
WOULD SUGGEST 17-23 TO 1 SNOW TO LIQUID RATIOS. SINCE THE SYSTEM IS
MOVING SO FAST...TRENDED MORE TOWARD THE GFS AND NAM SOLUTIONS.
THIS WOULD PRODUCE A 1 TO 2 INCH SNOW BAND ACROSS NORTHEAST IOWA AND
AND SOUTHWEST WISCONSIN...AND AROUND AN INCH NORTHWARD TO WISCONSIN
10.
ON SATURDAY AFTERNOON AND NIGHT...ANOTHER SHORT WAVE TROUGH WILL
MOVE SOUTHEAST THROUGH THE REGION. UNLIKE YESTERDAY...HAS THE LEFT
ENTRANCE REGION OF THE 250 MB JET A BIT FURTHER SOUTHEAST. AS A
RESULT...THE OMEGA IS NOT AS STRONG OR DEEP AS IT WAS YESTERDAY.
DESPITE THIS THERE IS MODERATE 270 TO 280K LIFT AHEAD OF THIS WAVE
AND THIS WILL ONCE AGAIN BRING SOME MOISTURE AND WARMER AIR ALOFT
FROM THE NORTHERN AND CENTRAL PLAINS. HOWEVER 01.09Z SREF SHOWS
FEWER MEMBERS HAVING 200 MB OR GREATER OF DENDRITIC GROWTH. THE COBB
DATA SUGGESTS 17-22 TO 1 SNOW TO LIQUID RATIOS. THIS WOULD RESULT IN
AROUND AN INCH OF SNOW FOR MUCH OF THE AREA.
FROM LATE SUNDAY AFTERNOON INTO SUNDAY NIGHT...THE MODELS SHOW YET
ANOTHER SHORT WAVE TROUGH WILL BE MOVING SOUTHEAST THROUGH THE
REGION. BY THIS TIME...THE AIR MASS WILL BE A BIT WARMER. AS A
RESULT...THE BEST ISENTROPIC LIFT IS TAKING PLACE BETWEEN 280 AND
300K. WITH THE AIR MASS WARMER...THERE IS LESS OF A LAYER IN
DENDRITIC GROWTH ZONE. HOWEVER THERE IS A BIT MORE MOISTURE FOR THIS
SYSTEM TO WORK WITH...SO IT LOOKS LIKE SNOW TOTALS WILL RANGE FROM 1
TO 2 INCHES.
OVERALL...IT LOOKS LIKE SNOW TOTALS DURING THE NEXT 3 DAYS WILL
RANGE FROM 2 TO 5 INCHES.
.LONG TERM...MONDAY THROUGH FRIDAY
345 PM CDT FRI FEB 1 2013
ON MONDAY NIGHT AND TUESDAY MORNING...ANOTHER SHORT WAVE WILL BE
MOVING SOUTHEAST THROUGH THE REGION. LIKE THE SYSTEM ON SUNDAY AND
SUNDAY NIGHT...THERE IS NOT MUCH OF THE THE ATMOSPHERIC COLUMN IN
THE DENDRITIC GROWTH ZONE...BUT THERE IS MORE MOISTURE FOR THIS
SYSTEM TO WORK WITH. AS A RESULT...THE SNOW TO LIQUID RATIOS LOOK TO
BE 15-20 TO 1. WITH A TENTH TO 2 TENTHS OF INCH OF QPF...THERE COULD
BE THE POTENTIAL OF ANOTHER 1 TO 3 INCHES OF SNOW.
IT STILL LOOKS LIKE ANOTHER SYSTEM WILL AFFECT THE AREA FROM
WEDNESDAY NIGHT INTO THURSDAY. HOWEVER THE MODELS HAVE BEEN MUCH
LESS CONSISTENT WITH THEIR PRECIPITATION AMOUNTS AND THE LOCATION OF
THIS SYSTEMS WARM FRONT. AS A RESULT...THERE IS MUCH LESS CERTAINTY
THAN THE PREVIOUS 4 SYSTEMS.
&&
.AVIATION...THROUGH 06Z SUNDAY
1126 PM CST FRI FEB 1 2013
THE SNOW CONTINUES TO MOVE SOUTHEAST ACROSS THE REGION WITH THE
LOCAL RADAR SHOWING THAT THE BULK OF IT SHOULD BE PAST BOTH TAF
SITES BY 06Z. STILL SOME RETURNS SHOWING UP ON THE KMPX RADAR WITH
SURFACE OBSERVATIONS SHOWING VISIBILITIES DOWN TO 3 OR 4 MILES AT
TIMES. WILL SHOW THIS IN THE TAFS UNTIL THE WINDS SWING AROUND TO
THE NORTH/NORTHWEST ONCE THE SURFACE LOW MOVES ACROSS NORTHERN
IOWA INTO ILLINOIS. HIGH PRESSURE OVER MANITOBA WILL QUICKLY MOVE
OVER THE REGION SATURDAY ALLOWING THE CLOUDS TO SCATTER OUT FOR A
SHORT PERIOD BEFORE THE NEXT SYSTEM STARTS TO COME IN. THE 02.00Z
NAM SUGGEST THE PV ADVECTION IN THE 500-300 MB LAYER WILL BE
STRONGER WITH THIS NEXT SHORT WAVE TROUGH THAN WITH THE ONE THIS
EVENING WITH UP TO 12 PVU/S POSSIBLE. THE WAVE SHOULD ALSO PRODUCE
WEAK TO MODERATE QG CONVERGENCE ON THE 850-500 MB LAYER.
HOWEVER...THERE SHOULD BE VERY LITTLE FRONTOGENESIS WITH JUST A
WEAK SIGNAL IN THE 1000-850 MB LAYER. THE BEST ISENTROPIC UP GLIDE
WILL SLIDE WEST OF THE REGION WITH ONLY 1 UBAR/S POSSIBLE ON THE
275K SURFACE. EXPECT THAT THE FORCING WITH THIS WAVE WILL BE
ENOUGH TO GENERATE ANOTHER ROUND OF SNOW WITH MVFR CONDITIONS AND
WILL BRING THE SNOW INTO BOTH TAF SITES AROUND 03.03Z.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
344 PM CST FRI FEB 1 2013
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
SHORT TERM...BOYNE
LONG TERM...BOYNE
AVIATION...04
AREA FORECAST DISCUSSION
NWS LINCOLN IL
333 AM CST MON FEB 4 2013
.DISCUSSION...
ISSUED 306 AM CST MON FEB 4 2013
WEAK HIGH PRESSURE SLIDING EAST AS ANOTHER WAVE OF PRECIP MOVES
ACROSS NRN IL THIS MORNING. NOT QUITE OUT OF THE INFLUENCE OF THE
PATTERN JUST YET...THE FIRST COUPLE OF ISSUES FOR THE FORECAST ARE
THE NEXT CLIPPER SYSTEMS MOVING THROUGH THE MIDWEST UNTIL THE END
OF THE WEEK. CONSIDERING THE PATTERN...THE AGREEMENT BTWN THE
MODELS IS IMPRESSIVE. NOT A LOT OF CHANGE IN THE FORECAST OVERALL
AS SOME RUN TO RUN CONSISTENCY IN THE MED AND LONGER RANGE. SOME
MINOR ISSUES IN THE SHORT TERM WITH PRECIP TODAY. ANOTHER ISSUE
FOR AS A RESULT OF THE SERIES OF WAVES MOVING THROUGH...NON
DIURNAL TEMPS FOR A COUPLE OF PERIODS. OVERALL...FORECAST
REMAINING RATHER CONSISTENT.
SHORT TERM...TODAY AND TOMORROW...
SNOW AND ASSOCIATED SHORT WAVE TO THE NORTH THIS MORNING WAS
PREVIOUSLY SET TO COLLIDE WITH ANOTHER WAVE TO THE SOUTH MIDDAY.
HOWEVER...WAVE TO THE NORTH A LITTLE AHEAD OF SCHEDULE...WITH SFC
WAVE TO THE SOUTHWEST LAGGING A BIT BEHIND. HAVE PULLED POPS DOWN
A BIT TO REFLECT THE DROP IN PROBABILITY...KEEPING SLIGHTS IN THIS
MORNING FOR EASTERN HALF OF CWA. BUT THIS AFTERNOON MAY SEE A
BETTER CHANCE WITH THE SOUTHERN WAVE IN THE SE. NAM/ECMWF/GFS
TRENDING A LITTLE DRIER...AND THE RUC IS COMPLETELY DRY THIS
AFTERNOON UNTIL THE WAVE PULLS OUT LATER THIS AFTERNOON. TEMPS A
BIT WARMER TODAY AS WELL WITH A SOUTHERLY COMPONENT RETURNING TO
THE SFC FLOW...ALBEIT WEAK. TOMORROWS WAVE PASSING JUST TO THE
NORTH AND CHANCES FOR PRECIP CONFINED WELL TO THE NORTH
AGAIN...WITH SIMILAR TEMPS TOMORROW AS TODAY...WITH BREEZY
WESTERLY WINDS KEEPING SOME WARM AIR MOVING INTO THE CWA.
LONG TERM...WEDNESDAY THROUGH SUNDAY...
WEDNESDAY DRY AND WARM AGAIN AHEAD OF THE NEXT SYSTEM FOR WED
NIGHT INTO THURSDAY. THOUGH THREAT FROM THE WEST WILL INCREASE FOR
THE OVERNIGHT HOURS ON WED NIGHT...THE BEST CHANCES WILL COME WITH
THE PASSAGE OF THE SFC BOUNDARY ON THUR/THU NIGHT. LAST MODEL RUN
DIVERGES SOMEWHAT WITH THE SOLUTIONS FOR THIS PARTICULAR WAVE. A
TROF DEEPENS OVER THE WEST COAST...AND THIS PARTICULAR SYSTEM IS
A SMALL PIECE OF THE ENERGY EJECTING OUT AHEAD OF THE MAIN TROF.
THE ECMWF IS FAR MORE AMPLIFIED WITH THIS SMALL WAVE...AND THE GFS
IS A BIT LESS SO...WITH A WEAKER BUT MORE DIFFUSE AND SLOWER
PASSAGE OF THE SFC SYSTEM UNTIL IT PASSES ILX FA. CONCERNS FOR THE
SOLUTION DIFFERENCES ARE MINIMAL AT THIS POINT...AS MAJORITY OF
THU AFTERNOON AND INTO THE EVENING ARE RAIN. SOLUTION DIFFERENCES
WILL LIKELY IMPACT QPF AS TIME GETS CLOSER. MAIN ISSUE WITH THIS
SYSTEM AT THIS POINT IS THE CONCERN FOR FZRA IN THE NRN HALF OF
THE CWA WITH THE MORNING PRECIP ON THURSDAY. NEXT SYSTEM OF
INTEREST WILL MOVE INTO THE REGION SAT/SUN CREATING THE POTENTIAL
FOR A MESSY WEEKEND. HOWEVER...THE HANDLING OF THE WAVE/TROF OVER
THE WEST VARIES WIDELY BTWN THE ECMWF AND THE GFS...AND FROM THEIR
PREVIOUS SOLUTIONS...AND WILL KEEP THE MENTION CONSERVATIVE FOR
NOW.
HJS
&&
.AVIATION...
ISSUED 1135 PM CST SUN FEB 3 2013
WIDESPREAD MID AND HIGH CLOUDS EXPECTED OVERNIGHT...WITH SNOW
THREAT STILL TRACKING ACROSS NORTHERN ILLINOIS PER LATEST MODELS.
HAVE SOME CONCERN FOR LOW LEVEL WIND SHEAR...AS LOW PRESSURE
APPROACHES WEST CENTRAL ILLINOIS. CONDITIONS AT CENTRAL ILLINOIS
TAF SITES SHOULD FALL A BIT SHY FOR INCLUSION OF LLWS GROUP...BUT
FORECAST SOUNDINGS SHOWING WINDS TURNING SOUTHWEST AND INCREASING
TO AROUND 30-35 KNOTS BY AROUND 2000 FEET...BEGINNING AROUND 09Z
AROUND KPIA/KSPI AND TOWARD 15Z AT KCMI. THESE WOULD LAST FOR A
FEW HOURS BEFORE THE LOW ARRIVES.
SURFACE WINDS EXPECTED TO TURN NORTHWEST FOLLOWING PASSAGE OF A
COLD FRONT TOWARD MIDDAY. NAM AND RAP MODEL GUIDANCE INDICATE
MVFR CEILINGS LIKELY TO SPREAD IN BEHIND THIS FRONT FOR MUCH OF
THE AFTERNOON. ANY THREAT OF RAIN OR SNOW WOULD BE MORE LIKELY
AROUND KCMI...BUT CHANCES APPEAR LOW ENOUGH TO INCLUDE AT THIS
POINT. VFR CONDITIONS EXPECTED TO DEVELOP FROM WEST TO EAST
SHORTLY AFTER SUNSET.
GEELHART
&&
.ILX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS LINCOLN IL
1137 PM CST SUN FEB 3 2013
.DISCUSSION...
ISSUED 815 PM CST SUN FEB 3 2013
MAIN CONCERN OVERNIGHT WILL BE WITH TEMPERATURES...AS EVENING
READINGS HAVE BEEN RUNNING SEVERAL DEGREES ABOVE THE FORECAST
CURVE. HAVE MADE SOME ADJUSTMENTS TO COMPENSATE...AS RAPIDLY
INCREASING HIGH CLOUDS SHOULD PREVENT ANY SIGNIFICANT TEMPERATURE
FALLS OVER THE NEXT COUPLE HOURS. STILL LOOKS LIKE THEY SHOULD
STEADY OUT OR SLOWLY RISE AFTER MIDNIGHT.
LATEST RADAR MOSAICS LOOKING FAIRLY DRAMATIC OVER THE NORTHERN
THIRD OF ILLINOIS...BUT THESE RETURNS ARE LARGELY MID LEVEL
CLOUDS. LATEST MODELS CONTINUE TO INDICATE ANY SNOW THREAT WILL
REMAIN ACROSS NORTHERN ILLINOIS OVERNIGHT.
GEELHART
&&
.AVIATION...
ISSUED 1135 PM CST SUN FEB 3 2013
WIDESPREAD MID AND HIGH CLOUDS EXPECTED OVERNIGHT...WITH SNOW
THREAT STILL TRACKING ACROSS NORTHERN ILLINOIS PER LATEST MODELS.
HAVE SOME CONCERN FOR LOW LEVEL WIND SHEAR...AS LOW PRESSURE
APPROACHES WEST CENTRAL ILLINOIS. CONDITIONS AT CENTRAL ILLINOIS
TAF SITES SHOULD FALL A BIT SHY FOR INCLUSION OF LLWS GROUP...BUT
FORECAST SOUNDINGS SHOWING WINDS TURNING SOUTHWEST AND INCREASING
TO AROUND 30-35 KNOTS BY AROUND 2000 FEET...BEGINNING AROUND 09Z
AROUND KPIA/KSPI AND TOWARD 15Z AT KCMI. THESE WOULD LAST FOR A
FEW HOURS BEFORE THE LOW ARRIVES.
SURFACE WINDS EXPECTED TO TURN NORTHWEST FOLLOWING PASSAGE OF A
COLD FRONT TOWARD MIDDAY. NAM AND RAP MODEL GUIDANCE INDICATE
MVFR CEILINGS LIKELY TO SPREAD IN BEHIND THIS FRONT FOR MUCH OF
THE AFTERNOON. ANY THREAT OF RAIN OR SNOW WOULD BE MORE LIKELY
AROUND KCMI...BUT CHANCES APPEAR LOW ENOUGH TO INCLUDE AT THIS
POINT. VFR CONDITIONS EXPECTED TO DEVELOP FROM WEST TO EAST
SHORTLY AFTER SUNSET.
GEELHART
&&
.PREV DISCUSSION...
ISSUED 249 PM CST SUN FEB 3 2013
A WAVE TRAIN OF WEATHER SYSTEMS WILL START OFF THE FORECAST...WITH
PRECIP CHANCES ON MONDAY, TUESDAY AND WED NIGHT-THURSDAY. THE LAST
SYSTEM OF NOTE FOR THIS FORECAST WILL BE DEEPER LOW PRESSURE
LIFTING THROUGH THE UPPER MIDWEST ON SAT NIGHT-SUNDAY...WITH A FEW
THUNDERSTORMS POSSIBLE SUNDAY ALONG WITH MODERATE RAINS AND VERY
MILD CONDITIONS.
SHORT TERM...TONIGHT THROUGH TUESDAY.
THE LINGERING FLURRIES FROM THE MOST RECENT SYSTEM WILL DEPART
FROM OUR EASTERN COUNTIES INTO INDIANA BY 4 PM. CLEARING SKIES
WILL CONTINUE TO PROGRESS EASTWARD IN THEIR WAKE. HOWEVER...A
QUICKLY ARRIVING MID-LEVEL CLOUD DECK WILL AFFECT SCHUYLER AND
FULTON COUNTIES BETWEEN 2 AND 3 PM...AND SLIDE EAST ACROSS AT
LEAST OUR NORTHERN COUNTIES THE REST OF THE AFTERNOON AND EVENING.
THAT INITIAL BAND OF CLOUDS IS RELATIVELY NARROW...BUT REINFORCING
MID-CLOUDS IN THE DAKOTAS AND SW MINNESOTA WILL EVENTUALLY SLIDE
SOUTHEAST TOWARD OUR COUNTIES MONDAY MORNING.
AN UPPER SHORTWAVE ON THE NORTHERN END OF AN INVERTED TROUGH WILL
TRIGGER A BAND OF LIGHT SNOW ACROSS SOUTHERN MINNESOTA INTO
NORTHERN ILLINOIS AND SOUTHERN WISCONSIN BETWEEN MIDNIGHT AND 6
AM. FLURRIES OR LIGHT SNOW COULD POSSIBLY EXTEND AS FAR SOUTH AS
LACON AND EL PASO BEFORE 6 AM MONDAY. LOW PRESSURE ON THE SOUTHERN
END OF THAT INVERTED TROUGH WILL MOVE ACROSS MISSOURI BY MONDAY
MORNING...EVENTUALLY PASSING ACROSS CENTRAL ILLINOIS. AS IT
REACHES EASTERN IL...IT WILL PHASE BETTER WITH THE UPPER WAVE AND
POSSIBLY TRIGGER LIGHT RAIN OR SNOW SHOWERS EAST OF I-57 AND
SOUTHWEST TO NEAR SHELBYVILLE. THE 12Z MODELS ARE SHOWING A DRIER
TREND IN OUR COUNTIES NEAR THE TRACK OF THAT SURFACE LOW.
HOWEVER...WE ONLY TRENDED A LITTLE LOWER WITH THE POPS INSTEAD OF
GOING COMPLETELY DRY WITH THE FIRST INDICATION OF NEARLY DRY
CONDITIONS ACROSS OUR EASTERN FORECAST AREA MONDAY INTO MONDAY
EVE.
ON TUESDAY...A CLIPPER-TYPE SYSTEM WILL MOVE SOUTHEAST FROM
MINNESOTA ACROSS WISC AND INTO THE EASTERN GREAT LAKES BY LATER
TUES NIGHT. THE PRIMARY REGION OF ISENTROPIC LIFT AND SHORTWAVE
FORCING FOR PRECIP WILL REMAIN NORTH OF OUR COUNTIES. WE MAY SEE
SOME FLURRIES ALONG AND NORTH OF I-74...BUT CHANCES OF MEASURABLE
SNOW IN OUR AREA ON TUESDAY LOOK QUITE LOW.
LONG TERM...WEDNESDAY THROUGH SUNDAY.
AS THE TUESDAY SYSTEM DEPARTS...A WARMING TREND WILL BEGIN ACROSS
THE AREA...IN RESPONSE TO A BUILDING RIDGE IN THE WESTERN PLAINS
STATES. THE UPPER FLOW WILL BECOME MORE ZONAL BRINGING IN MORE
PACIFIC BASED AIR.
IN THAT FAST WESTERLY FLOW...A LOW PRESSURE SYSTEM WILL DRAG A COLD
FRONT ACROSS IL ON THURSDAY. A BETTER TAP ON GULF MOISTURE WILL
BEGIN AHEAD OF THIS SYSTEM...BRINGING DEWPOINTS INTO THE UPPER 30S
AND HIGHS INTO THE LOW 40S NORTH AND NEAR 50 SOUTH. SHOWERS ARE
EXPECTED TO DEVELOP ALONG THE FRONT LATE WEDNESDAY NIGHT AND
THURS. RISING TEMPERATURES WED NIGHT SHOULD HELP TO KEEP THE
PRECIPITATION AS ONLY RAIN INSTEAD OF FREEZING RAIN...BUT WE CAN
NOT RULE OUT SOME AREAS AT OR BELOW FREEZING ACROSS THE NORTHWEST
WHEN RAIN BEGINS TO REACH THE GROUND BEFORE SUNRISE THURSDAY. THAT
SAME THERMAL PROFILE MAY BE PRESENT ALONG AND NORTH OF I-74 TOWARD
CHAMPAIGN/DANVILLE EARLY THURSDAY MORNING...WITH A PERIOD OF
FREEZING RAIN POSSIBLE. AT THIS POINT...THE WARMING SOUTHERLY
WINDS LOOK STRONG ENOUGH AT MID LEVELS TO WARM THE RAIN BETWEEN
+5C TO +7C. THAT WILL MAKE IT MORE DIFFICULT TO FREEZE RAIN FROM
THAT WARM OF A TEMPERATURE. ANY ICING WOULD MAINLY BE ON ELEVATED
SURFACES THAT REMAIN COLD IF AT ALL...AND THE ICE WOULD MELT BY
AFTERNOON AS AIR TEMPS RISE ABOVE FREEZING.
THE PRECIP WILL TAPER OFF AS THE COLDER AIR ARRIVES...POSSIBLE
CHANGING RAIN TO SNOW IN THE EAST/SOUTHEAST AREA.
THEN A BREAK IN THE PRECIP IS EXPECTED FROM LATER THURSDAY NIGHT
THROUGH FRIDAY NIGHT UNDER WEAK HIGH PRESSURE. WARMER TEMPS
THURSDAY WILL BE TEMPERED ON FRIDAY BEHIND THE COLD FRONT...BUT
SATURDAY WILL SEE HIGHS CLIMB WELL INTO THE 40S AHEAD OF THE STORM
SYSTEM DEVELOPING IN THE PLAINS. A SOLID TAP ON GULF MOISTURE BY
SUNDAY MORNING WILL SET THE STAGE FOR RAIN SHOWERS DEVELOPING
SATURDAY NIGHT. INSTABILITY PARAMETERS AND DYNAMIC FORCING LOOK
FAVORABLE FOR A WAVE OF THUNDERSTORMS IN CENTRAL IL ON SUNDAY INTO
SUNDAY EVENING. WE CANT RULE OUT THE POTENTIAL FOR A FEW SEVERE
STORMS SUNDAY AFTERNOON AND EVENING...MAINLY EAST OF THE ILLINOIS
RIVER. THE TRACK OF THE LOW WILL PLAY A MAJOR ROLL IN OUR
POTENTIAL FOR STORMS...AND WILL BE WATCHED CLOSELY IN THE COMING
WEEK.
SHIMON
&&
.ILX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS TOPEKA KS
350 AM CST MON FEB 4 2013
.DISCUSSION...
INVERTED SURFACE TROF BISECTING THE FORECAST AREA THIS
MORNING...WITH COLDER AIR STILL TO THE NORTH AT THIS HOUR. UPPER
WAVE MOVING THROUGH NORTHWEST KANSAS TO THE SOUTHEAST AND WILL SWEEP
COLD FRONT ACROSS THE FORECAST AREA THROUGH THE DAY TODAY.
TEMPERATURES EXPECTED TO STAY WELL MIXED INTO THE 40S FOR THE EAST
CENTRAL COUNTIES UNTIL THIS AFTERNOON WHEN FRONT COMES
THROUGH...WITH NORTH CENTRAL COUNTIES STARTING OFF IN THE LOW TO
MIDDLE 30S BUT DROPPING SLOWLY AS THE DAY GOES ON.
ALSO KEEPING AN EYE ON THE CLOUD DECK MOVING QUICKLY SOUTH OUT OF
SOUTH DAKOTA AND NORTHEAST NEBRASKA. RAP RH CHARTS BRING THIS DECK
INTO THE I70 CORRIDOR AROUND THE NOON HOUR BEFORE BREAKING UP AS IT
MOVES SOUTHWARD. FAR NORTHEAST COUNTIES EXPECTED TO REMAIN THE
COOLEST WITH TEMPERATURES IN THE MIDDLE 30S AND FALLING THIS
AFTERNOON. WINDS BECOME BREEZY FROM THE NORTH FOR A TIME AS THE
FRONT PUSHES THROUGH...BUT THEN WINDS LIGHTEN AND VEER AROUND TO THE
SOUTHWEST BY EARLY MORNING HOURS. OVERNIGHT LOWS SHOULD DROP INTO
THE 20S MOST AREAS AS THE WINDS DIMINISH AND CLOUDS DECREASE.
67
TUESDAY AND WEDNESDAY...ANOTHER WEAK COLD FRONT WILL PUSH THROUGH
TUESDAY AS NORTHWEST FLOW CONTINUES ALOFT. SURFACE HIGH PRESSURE
MOVES RAPIDLY EAST TUESDAY NIGHT ALLOWING WAA TO ONCE AGAIN
RETURN. HOWEVER...WAA NOT STRONG INITIALLY ON WEDNESDAY AFTERNOON
WITH ONLY A MODEST INCREASE IN 850MB TEMPS OF ABOUT 2-3C AND A
3-4DM INCREASE IN HEIGHTS. 925MB-850MB TRANSPORT WINDS WILL BE
AROUND 20-25KTS FROM THE SOUTH/SOUTHEAST...AND WILL ADVECT A
DECENT MOISTURE PLUME NORTH INTO THE CWA AHEAD OF ANOTHER
ADVANCING COLD FRONT FOR WEDNESDAY NIGHT AND INTO THURSDAY
MORNING. WEDNESDAY LOOKS TO BE THE WARMEST DAY OF THE WEEK WITH
HIGHS APPROACHING OR TOPPING 60.
WEDNESDAY NIGHT AND THURSDAY...PW VALUES INCREASE TO AROUND AN
INCH FOR LATE WEDNESDAY NIGHT FOR AREAS MAINLY SOUTH OF INTERSTATE
70. INCREASED POPS AS MODELS COMING INTO AGREEMENT AS FAR AS
PLACEMENT. HOWEVER...MODELS DO DIVERGE ON QPF WITH THE NAM BEING
VERY AGGRESSIVE WITH A BULLS EYE OVER THE SOUTHERN PORTION OF THE
CWA OF AN INCH OF PRECIP. FEEL THIS IS A BIT OVERDONE...AND HAVE
GONE WITH THE MORE CONSISTENT AND CONSERVATIVE QPF VALUES OF THE
ECMWF AND GFS. NAM QUITE AGGRESSIVE ON MUCAPE VALUES AS WELL WITH
UP TO 500 J/KG. MENTIONED ISOLATED THUNDER WEDNESDAY NIGHT SOUTH
OF INTERSTATE 70...BUT FEEL THE NAM INSTABILITY VALUES A BIT
INFLATED. SHEAR PROFILES LOOK TO SUPPORT THUNDER AS WELL WITH
0-6KM VALUES OF AROUND 40KTS. THE SYSTEM SHOULD CLEAR THE CWA BY
18Z. TEMPERATURES WILL BE SLIGHTLY COOLER BEHIND THE FRONT OF
AROUND 10 DEGREES...AND WITH SKIES CLEARING OUT QUICKLY...SHOULD
SEE A RETURN TO 40`S AND 50`S BY THURSDAY AFTERNOON.
EXTENDED...(THURSDAY NIGHT THROUGH THE WEEKEND)...NEXT SYSTEM TO
AFFECT THE REGION WILL BE SATURDAY. QUITE A BIT OF DIVERGENCE IN
THE MODELS AT THIS TIME AS TO THE EVOLUTION OF THE SYSTEM AND ITS
IMPACT ON THE PLAINS. THE GFS ESSENTIALLY HAS THE SYSTEM BECOME
CUTOFF OVER THE DESERT SOUTHWEST AS THE NORTHERN STREAM OF THE
JET PINCHES IT OFF OVER THAT REGION OF THE COUNTRY WITH A FAST
MOVING SHRTWV ACROSS THE NORTHERN PLAINS. THE ECMWF HAS THE SYSTEM
MOVE RAPIDLY OUT OF THE DESERT SOUTHWEST AS A CLOSED H5 LOW RIGHT
ACROSS KANSAS. GIVEN THE EVOLUTION OF SYSTEMS THIS PAST WINTER
SEASON...FEEL THE ECMWF SCENARIO NOT LIKELY. HOWEVER...LOWERED
POPS A BIT SATURDAY TO REFLECT THE DISAGREEMENT IN MODELS. BEHIND
THE SYSTEM...PROFILES LOOK COLD ENOUGH TO BEGIN SUPPORTING SLEET
OR SNOW OVER THE NORTHWEST COUNTIES BY SUNDAY AFTERNOON.
01
&&
.AVIATION...
FOR 06Z TAFS...VFR CONDITIONS EXPECTED THROUGH THE PERIOD. A COLD
FRONT WILL TRACK SOUTHEAST THROUGH THE REGION OVERNIGHT...CAUSING
WINDS TO VEER FROM SOUTH TO NORTHWEST THIS MORNING. WINDS ARE
EXPECTED TO BECOME CALM TONIGHT AS A SURFACE HIGH TRACKS OVER
THE REGION. AREAS OF HIGH CLOUDS WILL REMAIN IN PLACE THROUGH MUCH
OF THE PERIOD.
ACH
&&
.TOP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
1159 PM EST SUN FEB 3 2013
.UPDATE...
ISSUED AT 949 PM EST SUN FEB 3 2013
UPSTREAM 00Z KINL SOUNDING SHOWED THAT RATHER SIGNIFICANT DRYING HAS
OCCURRED SINCE THE 12Z SOUNDING. OVERALL...IT`S NOT AN ENVIRONMENT
REALLY FAVORABLE FOR ANYTHING MUCH MORE THAN LIGHT LES. THIS DRIER
AIR HAS MADE AN IMPACT AS SATELLITE IMAGERY SHOWS A FAIR AMOUNT OF
DISTANCE BTWN THE MN SHORE AND LAKE EFFECT CLOUDS DEVELOPING OVER
THE LAKE. ALSO...WEBCAMS/SPOTTER REPORT FROM MOHAWK AND KCMX OB ALSO
INDICATE ONLY LIGHT LES IS OCCURRING. HAVE THUS CANCELLED THE ADVY
FOR THE WRN COUNTIES WITH ONLY AN INCH...MAYBE 2 OF ADDITIONAL SNOW
OVERNIGHT.
TO THE E...HEAVIER NW FLOW LES CONTINUES. AS IS TYPICAL...WRN MOST
BAND IS BECOMING A MORE DOMINANT BAND DUE TO ENHANCED CONVERGENCE
FROM LAND BREEZE OFF MARQUETTE COUNTY. THIS BAND IS STREAMING INTO
THE MUNISING/WETMORE SHINGLETON AREA. SPOTTER UNDER THIS BAND
REPORTED ABOUT AN INCH/HR SNOWFALL RATE. FARTHER E...ERN MOST BAND
ENHANCED BY CONVERGENCE FROM LAND BREEZE OFF ONTARIO IS STREAMING
INTO ERN WHITEFISH BAY. LATEST HIGH RES MODEL GUIDANCE REMAINS IN
AGREEMENT THAT WITH SOME WEAKENING OF THE GRADIENT WINDS...LAND
BREEZE OFF ONTARIO WILL MAKE SIGNIFICANT WESTWARD PROGRESS
OVERNIGHT...POSSIBLY TO AROUND GRAND MARAIS BY 12Z. THERE SHOULD BE
A HVY SNOW BAND ALONG THAT CONVERGENT ZONE AS IT SHIFTS W. WILL THUS
CONTINUE TO HIGHLIGHT THE AREA FROM MUNISING TO PINE STUMP JUNCTION
FOR HEAVIEST SNOWFALL OVERNIGHT INTO THE MORNING. WITH LAND BREEZE
OFF MARQUETTE COUNTY...A SECONDARY SNOWFALL MAX MAY OCCUR FROM AU
TRAIN/MUNISING AND TO POINTS SE FROM THERE.
&&
.SHORT TERM...(THIS EVENING THROUGH MONDAY)
ISSUED AT 358 PM EST SUN FEB 3 2013
12Z RAOBS/LATEST WV IMAGERY AND RUC ANALYSIS SHOW PERSISTENT DEEP
UPR TROF OVER E-CNTRL NAMERICA DOWNSTREAM OF HI AMPLITUDE RDG OFF
THE W COAST. A SHRTWV/ATTENDANT LO PRES TROF EMBEDDED IN THIS FLOW
CROSSED UPR MI THIS MRNG...DROPPING AS MUCH AS 3 TO 6 INCHES OF SN
IN AREAS NEAR LK SUP FAVORED FOR MOISTENING/UPSLOPE FLOW IN LLVL
W-NW WINDS. SINCE THE AIRMASS WAS SO DRY WITH PWAT NO MORE THAN
0.05-0.15 INCH...LOCATIONS AWAY FM LK MOISTENING SAW LESS THAN AN
INCH OF SN. IN THE WAKE OF THE TROF PASSAGE...A LLVL NW FLOW BTWN
THE DEPARTING TROF AND A HI PRES RDG MOVING INTO MN AND SHOWN BY THE
MQT VWP IS BRINGING A REINFORCING SHOT OF ARCTIC AIR WITH 12Z H85
TEMPS RANGING FM -20C AT GRB TO -24C AT INL AND -28C AT YPL. DESPITE
THE ABSOLUTE DRYNESS OF THE INCOMING AIRMASS WITH PWATS 0.05 TO 0.10
INCH AND LO INVRN BASE H9-875 SHOWN ON THE 12Z INL/YPL RAOBS...THESE
RAOBS INDICATE THE LOWER LYRS ARE MOIST ENUF IN A RELATIVE SENSE TO
SUSTAIN NMRS WIND PARALLEL LES BANDS SHOWN ON VSBL STLT IMAGERY.
AWAY FM THE NW WIND SN BELTS ESPECIALLY OVER THE SCNTRL WITH
DOWNSLOPE FLOW...DEEP LYR QVECTOR CNVGC/SUBSIDENCE IN THE WAKE OF
DEPARTING SHRTWV ARE CAUSING MOSUNNY CONDITIONS. BUT SFC TEMPS ARE
WELL BLO NORMAL.
TNGT...DEEP LYR QVECTOR DVGC/LARGER SCALE SUBSIDENCE IN THE WAKE OF
DEPARTING SHRTWV ARE FCST TO DOMINATE...AND FCST SDNGS SHOW INVRN
BASE FALLING TO 3-4K FT OVER THE W AND TO ARND 5K FT IN AREAS E OF
MQT. WITH SLOWLY SHIFTING /DIMINISHING NW LLVL FLOW OF ARCTIC AIR
DROPPING H85 TEMPS TO -20C TO -23C...EXPECT NMRS LES BANDS TO IMPACT
AREAS FAVORED BY NW WINDS. LONG FETCH INTO THE ERN CWA WL ALLOW FOR
MODIFICATION OF THE ARCTIC AIR...AND FCST PROFILES SHOW A RELATIVELY
DEEP DGZ WL OCCUPY A GOOD PORTION OF THE CONVECTIVE LYR. IN FACT...
THE 12Z NAM REMAINS QUITE CONSISTENT WITH EARLIER RUNS SHOWING SN/
WATER RATIOS OF 30:1 AT MUNISING THRU TNGT. A GOOD NUMBER OF THE
HIER RES MODELS ALSO INDICATE INCRSG LLVL CNVGC IN THE AREA E OF
MUNISING WITH DVLPMNT OF AN E LAND BREEZE FLOW OFF SE ONTARIO INTO
LUCE COUNTY. THIS COMBINATION OF FAVORABLE FACTORS WARRANTS
CONTINUING THE GOING LES WRNG FOR ALGER/NRN SCHOOLCRAFT/LUCE
COUNTIES. OVER THE W...RELATIVELY SHORT FETCH LENGTH OVER WRN LK SUP
SHORTENED FURTHER BY ICE BUILDUP OFF THE W SHORE WL TEND TO LIMIT
MODERATION OF THIS FRIGID AIRMASS. FCST PROFILES FOR THE WRN CWA
INDICATE THE DGZ OVER THE W WL OCCUPY ONLY THE LOWEST 1K FT OF SO OF
THE ATMOSPHERE. THIS LIMIT ON SN FLAKE SIZE SHOULD HOLD DOWN SN
ACCUMS. THE SOMEWHAT HEAVIER SN MIGHT FALL OVER ONTONAGON COUNTY
WITH MORE PERSISTENT LLVL CNVGC/HINT OF LAND BREEZE FLOW OFF NW WI.
WITH SLOWLY WEAKENING H925 WINDS...DIMINISHING BLSN MIGHT BE ENUF TO
ALLOW EARLY CANX OF LES ADVY OVER THE W AWAY FM ONTONAGON COUNTY.
BUT LEFT GOING ADVY ALONE FOR NOW EVEN THOUGH SN AMNTS MIGHT BE SUB
ADVY DUE TO EFFICIENT NATURE OF FINE SN FLAKES TO LIMIT VSBY.
MON...AS HI PRES RDG AXIS TO THE W SLIDES SLOWLY TO THE E...THE LLVL
FLOW IS PROGGED TO STEADILY BACK TO THE W BY LATE IN THE DAY.
ALTHOUGH H85 TEMPS ARE FCST TO RISE A FEW DEGREES TO -18C TO -21C BY
LATE IN THE DAY...INSTABILITY WL REMAIN MORE THAN SUFFICIENT FOR LES
TO CONTINUE. SLOWLY RISING H85 TEMPS MAY IMPROVE SN GROWTH OVER
THE W... BUT LINGERING LO INVRN BASE AND GENERAL ACYC NATURE OF THE
LLVL FLOW SHOULD ACT TO SUPPRESS THE SHSN INTENSITY. OVER THE E...
ALTHOUGH THE BANDS MIGHT BEGIN TO SHIFT TOWARD THE E...LINGERING
SHARP LLVL CNVGC IN AT LEAST PART OF THIS AREA WARRANTS MAINTAINING
GOING WRNG THRU THE DAY WITH FVRBL SN GROWTH PARAMETERS IN PLACE.
.LONG TERM...(MONDAY NIGHT THROUGH SUNDAY)
ISSUED AT 358 PM EST SUN FEB 3 2013
NO BIG CHANGES TO EXPECTED PATTERN SHIFT THAT OCCURS THROUGH THIS
WEEK AS COLD TROUGHING OVER EASTERN CONUS RETREATS INTO CANADA AS
FLOW BECOMES MORE ZONAL LATE THIS WEEK AND TURNS TO SPLIT FLOW
PATTERN BY NEXT WEEKEND. MAIN RESULT IS WARMER TEMPS RETURNING TO
UPR LAKES BY LATE THIS WEEK ALONG WITH A COUPLE CHANCES OF SYSTEM
SNOW ALONG THE WAY.
TO START THE LONG TERM ON MONDAY EVENING...EXPECT LK EFFECT OVER
THE EAST TO GRADUALLY FADE AWAY THROUGH THE NIGHT AS WINDS BACK AND
INVERSIONS CONTINUE TO LOWER. AFTER MIDNIGHT...MAJORITY OF SNOW
SHOWERS WILL BE TO THE EAST OF GRAND MARAIS INTO NORTHERN LUCE
COUNTY. MID CLOUDS AHEAD OF NEXT CLIPPER SYSTEM ALREADY WILL BE
SPILLING ACROSS CWA LATER MONDAY NIGHT WITH SOME SNOW PUSHING INTO
FAR WEST UPR MICHIGAN TOWARD DAYBREAK ON TUESDAY. TEMPS MAY TRY TO
PLUMMET QUICKLY MONDAY EVENING WELL BLO ZERO BEFORE RISING LATER.
COLDEST TEMPS WOULD BE OVER CNTRL AND EASTERN INTERIOR.
CLIPPER SYSTEM ALLUDED TO IS CURRENTLY PUSHING ASHORE OVER NORTHERN
BRITISH COLUMBIA. WAVE IS EXPECTED TO DIG FROM NORTHERN MN ACROSS WI
LATE MONDAY NIGHT THROUGH TUESDAY. THOUGH SFC TROUGH SLIDES SOUTH OF
UPR MICHIGAN...H85 TROUGH CROSSES UPR MICHIGAN THROUGH THE DAY ON
TUESDAY. EXPECT H85 TEMPERATURE AND MOISTURE ADVECTION ALONG WITH
DIVERGENCE ALOFT/H85-H7 FRONTOGENESIS TO SPREAD AREA OF LGT SNOW
ACROSS CWA. MIXING RATIOS LESS THAN 2G/KG AND SHORT DURATION OF
STEADY SNOW WILL LIMIT ACCUMS...BUT THERE IS A POTENTIAL FOR MORE
PERSISTENT FGEN TO RESULT IN A BIT MORE SNOW /2-3 INCHES/ OVER FAR
SCNTRL IMT-MNM-ESC. THIS MATCHES WELL WITH LATEST HPC WINTER WEATHER
GUIDANCE. ECMWF HAS BEEN CONSISTENT IN IMPACTING MOST OF CWA WITH
LGT SNOW. NAM HAS BEEN QUITE INCONSISTENT...PAINTING WIDESPREAD SNOW
OVER ALL CWA YDY AND HARDLY SHOWING ANY QPF WITH 12Z RUN TODAY. WE
HAVE NOTICED RECENTLY OVER LAST FEW WEEKS THAT WITH THESE CLIPPER
SYSTEMS MODELS HAVE HAD TENDENCY TO FORECAST HEAVIER SWATHS OF SNOW
FARTHER SOUTH LEADING UP TO SNOW EVENTS MORE ALONG STRONGER
925-850MB MOISTURE ADVECTION...BEFORE CORRECTING FARTHER TO THE
NORTH RIGHT BEFORE THE EVENT BEGINS. WILL PLAY THAT TREND WITH THIS
FORECAST AND GO WITH FARTHER NORTH ECMWF DEPICTION WITH QPF/SNOW.
12Z GFS HAS TRENDED THIS WAY AS WELL AND ACTUALLY SHOWS SFC LOW A
BIT FARTHER NORTH AS WELL.
AS SFC LOW OR AT LEAST TROUGHING MOVES INTO NORTHERN LOWER MICHIGAN
BY TUESDAY EVENING...WINDS BECOME ONSHORE NEAR LK SUPERIOR. SOME H85
AND EVEN H7 MOISTURE AROUND WITH H85 TEMPS DOWN BLO -13C. WINDS WILL
BE STEADILY BACKING FROM NORTH TO WEST-NORTHWEST THROUGH THE NIGHT.
SCT LK EFFECT SNOW SHOWERS SEEM REASONABLE ALONG LK SUPERIOR. SHOULD
NOT BE BIG DEAL THOUGH AS INVERSIONS QUICKLY LOWER AND WITH PLENTY
OF LOW-LEVEL WIND SHEAR. ISOLD SNOW SHOWERS END QUICKLY ON WEDNESDAY
MORNING ONCE WINDS BECOME MORE SOUTHERLY AHEAD OF NEXT CLIPPER
SYSTEM ENTERING NORTHERN PLAINS.
MODELS HAVE BEEN CONSISTENT IN SHOWING ANOTHER ROUND OF SNOW WITH
THAT CLIPPER AFFECTING UPPER LAKES REGION SOMETIME FROM AS EARLY AS
WEDNESDAY MORNING THROUGH THURSDAY. GEM-NH QUICKEST AS IT HAS
STRONGER H85 LOW OVER NORTHERN MN BY WEDNESDAY AFTN RESULTING IN
MORE MOISTURE AND TEMP ADVECTION AT H85 INTO UPR MICHIGAN. GFS A BIT
SLOWER...FAVORING MOST QPF ON WEDNESDAY NIGHT. ECMWF SLIGHTLY
SLOWER...BUT STILL HAS MAJORITY OF QPF ON WEDNESDAY
NIGHT...ESPECIALLY WEST/CNTRL. SYSTEM IS SIMILAR TO ONE THAT MOVES
THROUGH ON TUESDAY...EXCEPT THIS ONE IS LACKING UPR JET SUPPORT BUT
HAS MORE MOISTURE TO WORK WITH AS H7 MIXING RATIOS ARE 2.5-3.0 G/KG
FLOWING INTO UPR MICHIGAN. 00Z ECMWF WAS FAIRLY WET WITH
QPF...SHOWING OVER 0.4 INCH OVER CNTRL CWA. PREVIOUS RUNS OF ECMWF
AND NEW 12Z RUN NOT AS MOIST...WITH UP TO 0.3 INCH. GFS STAYING ON
THE DRIER SIDE...AROUND 0.15 INCH. SEEMS LIKE IT WILL BE WETTER SNOW
AS H85 TEMPS ARE WARMER THAN -10C AND H7 TEMPS ARE ONLY SLIGHLY
COLDER. COLDER BLYR TEMPS IN TEENS/LOWER 20S PROBABLY ALLOW SLR/S TO
END UP AROUND CLIMO CENTERED ON 15:1. AT FIRST GLANCE...LOW-END ADVY
SNOWS MAY OCCUR OVER PORTIONS OF CWA.
THIS SYSTEM IS STILL OVER NORTHERN PACIFIC WELL TO SOUTH OF ALLUTIAN
ISLANDS. PLENTY OF TIME TO LATCH ONTO SPECIFICS BUT ENOUGH EVIDENCE
PRESENT TO INCREASE POPS TO LIKELY. POPS MAY NEED INCREASING FOR
THURSDAY MORNING OVER THE EAST...BUT JUST KEPT HIGH CHANCE FOR NOW
AS MAJORITY OF SYSTEM SNOW WILL BE FINISHING UP BY THAT TIME. ONCE
LOW SLIDES BY BLYR WINDS BECOME ONSHORE ALONG LK SUPERIOR THU NIGHT
AND THEN BACK OFFSHORE ON FRIDAY. DECREASING MOISTURE AND LACK OF
VERY COLD AIR SHOULD KEEP ANY LK EFFECT LIMITED INTO FRIDAY. OTHER
STORY THURSDAY INTO FRIDAY WILL BE SIGNS THAT WE WILL BE AT LEAST
TEMPORARILY BUSTING OUT OF OUR COLDER WEATHER PATTERN OF LATE WITH
HIGHS BOTH DAYS UPR 20S TO NEAR 30 DEGREES. MODELS HAVE BEEN
INSISTENT THAT COULD SEE SOME SUNSHINE LATER FRIDAY...SO TEMPS MAY
END UP ABOVE FREEZING IN SOME AREAS. SIMILAR TEMPS WILL CONTINUE
INTO THE WEEKEND.
FINALLY...SIGNALS EMERGING IN MODELS/ENSEMBLES THAT AS FLOW BECOMES
SPLIT NEXT WEEKEND...A SOUTHERN STREAM SYSTEM WILL LIFT INTO GREAT
LAKES NEXT SUNDAY INTO MONDAY. STRENGTH OF SYSTEM DEPENDS ON IF
SOUTHERN WAVE BECOMES NEGATIVELY TILTED AND WHETHER ANY PHASING CAN
OCCUR WITH NORTHERN STREAM. FOR WHAT IT IS WORTH...12Z RUNS OF ECMWF
AND GFS SHOW GENEROUS AMOUNTS OF QPF OVER UPPER LAKES LATE NEXT
SUNDAY INTO MONDAY. MAY EVEN BE ENOUGH WARM AIR WRAPPED INTO THE
SYSTEM TO BRING CHANCE OF RAIN/FREEZING RAIN INTO UPR LAKES. DID GO
AHEAD AND MENTION RAIN/SNOW MIX OVER THE SOUTHERN CWA WHICH MATCHES
UP WELL WITH SURROUNDING OFFICES. ELSEWHERE...LOOKS LIKE A WET
SYSTEM SNOW WOULD IMPACT MUCH OF UPR MICHIGAN. A BIT PREMATURE TO
GET TOO HUNG UP ON DETAILS...BUT WILL BE SOMETHING TO WATCH AS WE GO
THROUGH THE UPCOMING WEEK.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z MONDAY NIGHT)
ISSUED AT 1158 PM EST SUN FEB 3 2013
AT KCMX...NW FLOW OF ARCTIC AIR WILL CONTINUE TO SUPPORT LAKE
EFFECT SNOW SHOWERS. WITH SMALL FINE SNOWFLAKES DUE TO THE ARCTIC
AIR MASS BEING EFFECTIVE AT REDUCING VIS...IFR CONDITIONS WILL
PROBABLY BE THE RULE THRU THE MORNING. HOWEVER...AS IS TYPICAL OF
LAKE EFFECT SNOW...CONDITIONS MAY BE HIGHLY VARIABLE AT TIMES. AS
WINDS BACK SW THIS EVENING...EXPECT LAKE EFFECT CLOUDS/-SHSN TO END
WITH CONDITIONS BECOMING VFR.
AT KIWD...NW FLOW OVER THE LAKE WILL BE FIGHTING STRENGTHENING LAND
BREEZE OFF NW WI DURING THE NIGHT. AS A RESULT...KIWD WILL BE ON THE
EDGE OF LAKE EFFECT CLOUDS/-SHSN. OPTED TO KEEP MVFR CONDITIONS AT
KIWD THRU THE MORNING BEFORE LARGER SCALE BACKING OF FLOW MAKES
CLEARING MORE LIKELY. THAT SAID...IT`S QUITE POSSIBLE MVFR CIGS
COULD CLEAR OUT AT ANYTIME GIVEN SUCH CLOSE PROXIMITY OF CLEAR SKIES
TO THE W OF KIWD.
AT KSAW...ALTHOUGH PASSING -SHSN/FLURRIES COULD BRING MVFR CIGS AT
TIMES...EXPECT VFR CONDITIONS TO PREVAIL THRU THIS FCST PERIOD WITH
DOWNSLOPING WNW FLOW.
&&
.MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 358 PM EST SUN FEB 3 2013
EXPECT PERIODS OF HEAVY FREEZING SPRAY INTO TONIGHT WITH NW WINDS UP
TO 25-30KTS ADVECTING ARCTIC AIR OVER THE WATER. AS THE NW WINDS
DIMINISH LATER TONIGHT WITH APPROACH OF A HI PRES RIDGE...THE HEAVY
FREEZING SPARY WILL GRADUALLY DIMINISH AS WELL. EXPECT WINDS TO STAY
MAINLY BLO 25 KTS THROUGH THE UPCOMING WEEK AS A SERIES OF CLIPPER
LOW PRESSURE TROUGHS MOVE ACROSS. TEMPERATURES WILL GRAUDALLY WARM SO
THERE WILL NOT BE MUCH IN WAY OF FREEZING SPRAY.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
LAKE EFFECT SNOW WARNING UNTIL 7 PM EST MONDAY FOR MIZ006-007-
085.
LAKE SUPERIOR...
HEAVY FREEZING SPRAY WARNING UNTIL 7 AM EST MONDAY FOR LSZ244-
245-248>251-264>267.
HEAVY FREEZING SPRAY WARNING UNTIL 1 AM EST /MIDNIGHT CST/
MONDAY FOR LSZ241>243-263.
LAKE MICHIGAN...
NONE.
&&
$$
UPDATE...ROLFSON
SHORT TERM...KC
LONG TERM...JLA
AVIATION...ROLFSON
MARINE...KC/JLA
AREA FORECAST DISCUSSION
NWS GRAND RAPIDS MI
1142 PM EST SUN FEB 3 2013
.SYNOPSIS...
ISSUED AT 335 PM EST SUN FEB 3 2013
A CLIPPER WILL BRING SNOW TO FAR SOUTHERN LOWER MICHIGAN TONIGHT
AS LAKE EFFECT SNOW SHOWERS CONTINUE FOR AREAS NEAR LAKE MICHIGAN.
COLD WEATHER WILL CONTINUE THIS WEEK AND ANOTHER CHANCE OF SNOW
WILL ARRIVE LATE WEDNESDAY.
&&
.SHORT TERM...(THIS EVENING THROUGH TUESDAY NIGHT)
ISSUED AT 335 PM EST SUN FEB 3 2013
CLIPPER WILL BRING SOME SNOW TO THE I-94 CORRIDOR LATE TONIGHT AND
MONDAY MORNING. LATEST HRRR AND 12Z MODEL GUIDANCE SUGGEST HEAVIER
STRIPE OF F-GEN SNOWS WILL MISS OUR FORECAST AREA TO THE SOUTH BUT
EXPECT AT LEAST A COUPLE INCHES ACROSS SOUTHERN CALHOUN AND
JACKSON COUNTIES...JUST ENOUGH TO IMPACT THE MONDAY MORNING COMMUTE.
WENT WITH A WINTER WEATHER ADVISORY FOR JACKSON AND CALHOUN SINCE
THIS WILL BE A SYNOPTIC EVENT...WHILE CONTINUING THE LAKE EFFECT
SNOW ADVISORY FOR WESTERN COUNTIES DUE TO LAKE ACCUMS THERE TODAY
AND TONIGHT.
THE CLIPPER MOVES EAST WEDNESDAY AFTERNOON WITH JUST SOME RATHER
LIGHT LAKE EFFECT SNOW SHOWERS LEFT IN ITS WAKE. THE YET ANOTHER
CLIPPER APPROACHES IN FAST NW FLOW FOR TUESDAY AFTERNOON AND
EVENING. THE SFC LOW MOVES NORTH OF THE FORECAST AREA BUT SOME
CONVERGENCE AND LAKE ENHANCEMENT EXPECTED TO DROP MORE SNOW ACROSS
THE NORTHWEST FORECAST AREA...PERHAPS ENOUGH FOR AN ADVISORY.
.LONG TERM...(WEDNESDAY THROUGH SUNDAY)
ISSUED AT 335 PM EST SUN FEB 3 2013
SEASONABLE TEMPS ARE ANTICIPATED WEDNESDAY BEFORE TEMPS MODERATE
SLIGHTLY LATE IN THE WEEK AND FOR NEXT WEEKEND. DRY CONDITIONS ARE
ANTICIPATED WEDNESDAY WITH A HIGH PRESSURE RIDGE IN CONTROL BEFORE A
LOW PRESSURE SYSTEM BRINGS A CHC OF SNOW LATE WEDNESDAY NIGHT. A MIX
OF RAIN AND SNOW IS POSSIBLE FOR THURSDAY.
A HIGH PRESSURE RIDGE WILL BRING DRY WX FRIDAY INTO SATURDAY BEFORE
THE NEXT LOW PRESSURE SYSTEM BRINGS ANOTHER CHC FOR MIXED PCPN LATE
NEXT WEEKEND.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z MONDAY NIGHT)
ISSUED AT 1138 PM EST SUN FEB 3 2013
THE NEXT WAVE OF LOW PRESSURE IS MOVING INTO THE AREA FROM THE
WEST AT THIS TIME. WE ARE SEEING SOME OF THE SNOW INCREASING.
CONDITIONS ARE EXPECTED TO DETERIORATE THROUGH 10Z WITH WIDESPREAD
IFR OR LOWER CONDITIONS PREDICTED. THE TRACK OF THE STORM FAVORS
SOUTHERN TAF SITES LIKE KAZO...KBTL AND KJXN FOR THE LOWEST
CONDITIONS. BY 18Z...THE SYSTEM WILL BE PULLING AWAY AND A RETURN
TO MVFR OR BETTER IS FORECASTED.
&&
.MARINE...
ISSUED AT 335 PM EST SUN FEB 3 2013
ICE WILL CONTINUE TO ACCUMULATE ON THE LAKES AND CHANNELS THE NEXT
COUPLE DAYS. EXPECT THE WAVES AND WINDS TO DECREASE ENOUGH ON
MONDAY TO LET THE SCA EXPIRE.
&&
.HYDROLOGY...
ISSUED AT 335 PM EST SUN FEB 3 2013
COLD WEATHER WILL HOLD ON MUCH OF THIS WEEK. A THAW IS EXPECTED
NEXT WEEKEND. LOOKING FURTHER AHEAD...BY MONDAY LOW PRESSURE
TAKING A TRACK ACROSS NORTHERN MICHIGAN COULD BRING ENOUGH RAIN
AND SNOW MELT TO CAUSE ANOTHER ROUND OF PROBLEMS WITH ICE BREAKUP
ON THE RIVERS.
&&
.GRR WATCHES/WARNINGS/ADVISORIES...
MI...LAKE EFFECT SNOW ADVISORY UNTIL 7 PM EST MONDAY FOR MIZ056-064-
071-072.
WINTER WEATHER ADVISORY FROM 4 AM TO 1 PM EST MONDAY FOR MIZ073-
074.
LM...SMALL CRAFT ADVISORY UNTIL 7 AM EST MONDAY FOR LMZ844>849.
&&
$$
SYNOPSIS...OSTUNO
SHORT TERM...OSTUNO
LONG TERM...LAURENS
AVIATION...MJS
HYDROLOGY...OSTUNO
MARINE...OSTUNO
AREA FORECAST DISCUSSION
NWS NORMAN OK
1049 PM CST SUN FEB 3 2013
.AVIATION...
04/06Z TAFS...VFR CONDITIONS EXPECTED TO PREVAIL. LLWS WILL BE
INCLUDED FROM KSPS/KLAW UP THROUGH KOKC AND KPNC OVERNIGHT WITH
40-45KT LOW-LEVEL JET IN PLACE. COLD FRONT WILL MOVE OVER
TERMINALS 12Z TO 18Z SHIFTING WINDS TO NORTHERLY. STILL LOOKS LIKE
MOST OF SHOWER ACTIVITY WILL BE EAST OF TERMINALS AND WILL NOT BE
INCLUDED.
&&
.PREV DISCUSSION... /ISSUED 951 PM CST SUN FEB 3 2013/
UPDATE...
VERY MIXED SIGNALS FROM THE NUMERIC MODELS ABOUT PRECIPITATION
POTENTIAL OVERNIGHT. LOCAL WRF DEVELOPS WIDESPREAD LIGHT
PRECIPITATION... HRRR DOES AS WELL LATE... BUT OTHERS KEEP IT DRY.
WOULD NOT BE SURPRISED TO SEE RADAR ECHOES INCREASE OVERNIGHT BUT
00Z RAOB SHOWS A DEEP LAYER OF DRY AIR BELOW 475 MB SO WOULD
EXPECT MOSTLY VIRGA. SURFACE OBS ACROSS THE SOUTHERN PLAINS DO NOT
SHOW SIGNIFICANT INCREASE IN SURFACE DEWPOINTS POISED TO MOVE IN
EITHER. WILL KEEP POPS AS THEY ARE WITH THE RELATIVELY LOW POPS IN
EAST. MADE SOME ADJUSTMENTS TO THE HOURLY GRIDS BUT THESE WILL NOT
REQUIRE UPDATING THE TEXT PRODUCTS.
&&
.PRELIMINARY POINT TEMPS/POPS...
OKLAHOMA CITY OK 45 59 31 62 / 20 30 0 0
HOBART OK 46 61 29 63 / 20 20 0 0
WICHITA FALLS TX 48 64 36 64 / 20 30 0 0
GAGE OK 37 57 22 61 / 10 10 0 0
PONCA CITY OK 42 57 24 60 / 20 20 0 0
DURANT OK 49 59 39 64 / 30 70 10 0
&&
.OUN WATCHES/WARNINGS/ADVISORIES...
OK...NONE.
TX...NONE.
&&
$$
26/99/11
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
409 AM EST MON FEB 4 2013
.SYNOPSIS...
A DEEP 500 HPA TROUGH OVER EASTERN NORTH AMERICA WILL SLOWLY
WEAKEN AND LIFT OUT AS THE WEEK PROGRESSES. AT LEAST TWO CLIPPER
LIKE WAVES WILL MOVE ACROSS OUR AREA MONDAY AND TUESDAY...AS THIS
HAPPENS. BY THE END OF THE WEEK THE TROUGH AND LOW-LEVEL COLD AIR WILL
BE REPLACED BY A RIDGE AND GENERALLY WARMER AIR. THIS IMPLIES A
GENERAL WARMING TREND AS THE WEEK PROGRESSES AS 850 HPA
TEMPERATURES SHOULD BE ABOUT 1 STANDARD DEVIATION ABOVE NORMAL BY
THE WEEKEND.
&&
.NEAR TERM /UNTIL 9 AM THIS MORNING/...
TEMPERATURES MAINLY IN THE TEENS AND TWENTIES ACROSS THE REGION
THIS MORNING WITH STEADY WEST WINDS. CLOUDS FROM THE LAKE EFFECT
SNOW AREAS AND TERRAIN ENHANCED SNOW AREAS KEEP PEELING OFF TO THE
EAST AND DISSIPATING. MANY SITES IN THE LOWER SUSQUEHANNA VALLEY
HAVE BEEN CLEAR TO MOSTLY AT TIMES. CENTRAL AND WESTERN AREAS
REMAIN MOSTLY CLOUDY TO CLOUDY.
SNOW SHOWERS HAVE BEEN RELATIVELY CONFINED TO THE MOUNTAINS WITH
SLIGHTLY ENHANCED BANDS IN THE SW MOUNTAINS. THE LARGER LES BAND
HAS REMAINED MOSTLY CONFINED TO NORTH OF THE NY BORDER.
THE SNOW SHOWERS AND ACCUMULATING SNOWS SHOULD REMAIN FOCUSED INTO
THE SW MOUNTAINS AND MAINLY NEAR THE NY BORDER. THESE AREAS WILL
LIKELY WEAKEN A FEW HOURS EITHER SIDE OF 9AM BASED ON RAP AND HRRR.
&&
.SHORT TERM /9 AM THIS MORNING THROUGH 6 PM TUESDAY/...
MOST OF THE SNOW FROM THE LES AND UPSLOPE WILL DIMINISH THIS AM AS
A SHORT-WAVE APPROACHES FROM THE WEST. A MORE SYNOPTICLY DRIVEN
SNOW EVENT SHOULD DEVELOP LATE THIS MORNING AND EARLY THIS
AFTERNOON AND SPREAD TO THE EAST. THE COMBINED LES AND UPSLOPE
SNOWS WITH THE CLIPPER SHOULD BE ENOUGH TO KEEP THE ADVISORY UP
FOR THOSE LOCATION INTO THE OVERNIGHT PERIOD TONIGHT.
THE HIGH RESOLUTION MODELS ALL IMPLY A BRIEF PERIOD OF PERHAPS
MODERATE SNOW IN THE SW AREAS NEAR THE MD BORDER. THE 03Z SREF TOO
SUPPORTS THIS CONCEPT WITH SNOW ARRIVING A FEW HOURS EITHER SIDE
OF ABOUT 2 PM IN WESTERN PA. THE SREF IMPLIES 0.1 TO 0.20 INCHES
OF QPF IN SW MOUNTAINS WHICH WOULD BE A GOOD 4-5 INCHES OF VERY
FLUFFY SNOW. THE SREF MEAN IMPLIES ISOLATED 0.30 AREAS FOR STORM
TOTALS IN SOMERSET COUNTY. THE AXIS OF HIGHEST POPS AND HIGHEST
QPFS RUN ALONG THE PA/MD BORDER AND SOUTH. THOUGH BEST QPF IN OUR
AREA ARE IN SW MTS.
INDICATIONS ARE MOST OF THE SYNOPTIC SNOWS WILL END QUICKLY
BETWEEN 10 PM AND 1 AM TONIGHT. SHOWED SNOW AMOUNTS RAPIDLY
LOWERING TO NORTH WITH EVENT AND SNOW:WATER RATIOS IN THE 16 TO
20:1 RANGE.
SREF IS NOT OPTIMISTIC WITH THE 3-5 INCHES IN NW AREAS BUT THIS
COULD BE A MODEL RESOLUTION ISSUE AND DID NOT MESS WITH THIS TOO
MUCH UNTIL WE SEE NEWER GUIDANCE.
STRONG WESTERLY WIND MAXIMUM MOVES OVER SOUTHERN TIER MONDAY
AFTERNOON SO WE COULD BRING DOWN GUSTS IN 15 TO 20 MPH RANGE.
THE WINTER WEATHER ADVISORY FOR THE LAURELS TO 06Z TUESDAY AND
ISSUED A LAKE EFFECT SNOW ADVISORY FOR THE NW MTNS FROM 00Z MONDAY
TO 06Z TUESDAY.
THE NEXT WAVE SHOULD NOT ARRIVE UNTIL TUESDAY AFTERNOON OR EVENING
WITH ANOTHER SHOT AT SOME ACCUMULATING SNOWS OF 1-2 INCHES IN
NORTHERN TIER OF MORE FLUFFY SNOWS.
&&
.LONG TERM /TUESDAY NIGHT THROUGH SUNDAY/...
THE SECOND CLIPPER WILL BRING SNOW (SEE ABOVE) TO THE REGION
MAINLY LATE TUESDAY AFTERNOON INTO TUESDAY NIGHT. BEST CHANCE OF
1-2 INCHES OF SNOW SHOULD BE ACROSS NORTHERN AREAS.
PREVIOUS DISCUSSION...THE LARGER SCALE PATTERN TUESDAY THROUGH
SUNDAY SHOWS THE TROUGH OVER THE EAST WEAKENING AND LIFTING OUT.
BY THE WEEKEND THE 500 HPA HEIGHTS SHOULD BE SLIGHTLY ABOVE NORMAL
AS WELL AS THE 850 HPA TEMPERATURES. NORTHERN STREAM SHORT-WAVES
COULD BRING PRECIPITATION TUESDAY INTO EARLY
WEDNESDAY...FRIDAY...AND SUNDAY INTO MONDAY. SOME HINTS ARE THAT
LOW- LEVEL COLD AIR COULD BE AN ISSUE WITH WINTRY MIX POSSIBLE IN
NORTHERN REGIONS SHOULD THIS HIGHLY UNCERTAIN WAVE ARRIVE AS
FORECAST LATER THIS WEEKEND.
TUESDAY AFTERNOON INTO EARLY WEDNESDAY SHOULD SEE YET ANOTHER CLIPPER
SYSTEM SPREAD SOME LIGHT SNOW INTO THE AREA DRAGGING SOME COLD AIR
INTO THE REGION. NOT NEARLY AS COLD AS THE PREVIOUS SURGES HAVE
BEEN.
THE QPF VALUES ARE VERY LIGHT...NOT SURPRISING AS THE MAIN
LOW IS CURRENTLY FORECAST TO PASS TO OUR NORTH...VIOLATING ONE OF
THE RULES OF CLIPPERS AND WHERE YOU WANT TO BE TO GET MORE SNOW.
THE SYSTEM DOES DRAG A STRONG SURFACE RIDGE INTO THE REGION WHICH
SUGGESTS THE LOW-LEVEL COLD AIR WILL BE SLOW TO RETREAT ON
THURSDAY AND FRIDAY.
ANOTHER NORTHERN STREAM IMPULSE POSSIBLE IN THE LATE THURSDAY-
FRIDAY TIME-FRAME WITH INDICATIONS OF A LIGHT SNOW EVENT OVER
NORTHERN TIER AREAS. THIS SYSTEM ERODES THE STRONG SURFACE RIDGE A
BIT FRIDAY INTO SATURDAY. THERE ARE HINTS OF POSSIBLE MIXED
PRECIPITATION ISSUES AS GEFS SHOWS POTENTIAL FOR LIGHT FREEZING
RAIN IN CENTRAL AREAS OVER THE RETREATING COLD AIR. MAINLY SNOW
NORTHERN AREAS.
DESPITE THE HIGH HEIGHTS THIS COMING WEEKEND AND THE WARM 850 HPA
TEMPERATURES THE GEFS IMPLIES THE POTENTIAL AT LEAST IN NORTHERN
PA FOR A WINTRY MIX SUNDAY. THE STRONG SURFACE RIDGE IS PRESENT
AGAIN BY SATURDAY AND SUNDAY. GEFS AND CMCEFS SHOW A SORT OF
CLASSIC COLD AIR DAMMING SCENARIO OVER THE WEEKEND.
SO DESPITE THE LARGER SCALE HEIGHT RISES AND WARMER TEMPERATURES
ALOFT BY THE WEEKEND. THE LOW-LEVEL COLD AIR COULD MAKE THE TWO
EXPECTED PRECIPITATION EVENTS A BIT MORE INTERESTING THAN +1 TO
+3C 850 HPA TEMPERATURES WOULD IMPLY. AT THIS TIME MOST OF THE
PRECIPITATION EVENTS...TUEDAYS...FRIDAY AND SUNDAY TIME-FRAME LOOK
A BIT MOISTURE STARVED.
&&
.AVIATION /09Z MONDAY THROUGH FRIDAY/...
COLD FRONT HAS PUSHED EAST OF CENTRAL PA LATE THIS EVENING. A
DRIER WESTERLY FLOW IN THE WAKE OF THE FRONT SHOULD ENSURE VFR
CONDS ACROSS THE SUSQ VALLEY FOR THE REST OF THE NIGHT. OVER THE W
MTNS...RESIDUAL LOW LVL MOISTURE ASCENDING THE HIGH TERRAIN
CONTINUES TO PRODUCE -SN/LOWER VSBYS AT JST AS OF 03Z.
HOWEVER...LOWERING INVERSION HGTS WILL LIKELY CAUSE -SN TO TAPER
OFF AFTER MIDNIGHT. HOWEVER...MDL DATA SUPPORTS A CONTINUATION OF
MVFR STRATOCU OVERNIGHT AT BFD AND JST. IN ADDITION...A TIGHT PRES
GRADIENT BEHIND COLD FRONT WILL RESULT IN A GUSTY WIND OVERNIGHT.
BUFKIT SOUNDING DATA SUPPORTS FREQUENT GUSTS TO ARND 20KTS
OVERNIGHT ACROSS THE W MTNS.
A WEAK LOW PRES SYSTEM TRACKING SOUTH OF PA WILL SPREAD LIGHT
SNOW AND DETERIORATING VSBYS ACROSS MAINLY SOUTHWEST PA MONDAY
AFTN. IFR CONDS APPEAR LIKELY AT JST...WHERE OROGRAPHIC LIFT WILL
ENHANCE THE SNOW...AND POSSIBLE AT AOO.
OUTLOOK...
TUE...EARLY FOG POSSIBLE. LGT SNOW/REDUCED VSBYS POSS LATE.
WED...NO SIG WX EXPECTED.
THU...SNOW POSSIBLE LATE...MAINLY NORTH.
FRI...SNOW POSSIBLE EARLY...MAINLY NORTH.
&&
.CTP WATCHES/WARNINGS/ADVISORIES...
LAKE EFFECT SNOW ADVISORY UNTIL 1 AM EST TUESDAY FOR PAZ004-
005.
WINTER WEATHER ADVISORY UNTIL 1 AM EST TUESDAY FOR PAZ024-033.
&&
$$
SYNOPSIS...GRUMM
NEAR TERM...GRUMM
SHORT TERM...GRUMM/LAMBERT
LONG TERM...GRUMM/LAMBERT
AVIATION...FITZGERALD
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
248 AM EST MON FEB 4 2013
.SYNOPSIS...
A DEEP 500 HPA TROUGH OVER EASTERN NORTH AMERICA WILL SLOWLY
WEAKEN AND LIFT OUT AS THE WEEK PROGRESSES. AT LEAST TWO CLIPPER
LIKE WAVES WILL MOVE ACROSS OUR AREA MONDAY AND TUESDAY...AS THIS
HAPPENS. BY THE END OF THE WEEK THE TROUGH AND LOW-LEVEL COLD AIR WILL
BE REPLACED BY A RIDGE AND GENERALLY WARMER AIR. THIS IMPLIES A
GENERAL WARMING TREND AS THE WEEK PROGRESSES AS 850 HPA
TEMPERATURES SHOULD BE ABOUT 1 STANDARD DEVIATION ABOVE NORMAL BY
THE WEEKEND.
&&
.NEAR TERM /UNTIL 7 AM THIS MORNING/...
OBSERVATIONS AND SATELLITE INDICATED MANY LOCATIONS IN SOUTHERN
TIER AND SOUTHEAST HAVE BECOME MOSTLY CLEAR THOUGH PATCHES OF
CLOUDS ARE IMPLIED BY RADAR AND 11-3.9 MICRON DATA. RADAR SHOWS
SOME THIN BANDS OF LIGHT SNOW SHOWERS OVER CENTRAL
MOUNTAINS...MAINLY NEAR AND SOUTH OF THE RADAR.
SNOW SHOWERS ARE MORE PERSISTENT IN SOUTHWEST MOUNTAINS AND CLOSE
TO LAKE ERIE. CLOUDY OVER MOST OF WESTERN PA AND SW MOUNTAINS.
BEST IMPLIED SNOW BANDS ARE NOT IN OUR COUNTY WARNING AREA.
UPDATED CLOUDS AND POPS TO REFLECT CURRENT DATA AND MINOR TWEAKS
TO TEMPERATURES. BEST SNOW PROBS OF COURSE IN SW MOUNTAINS AND
WARREN AND MCKEAN COUNTIES. 13KM RAP SHOWS THE STRONGER BAND JUST
NORTH OF THE PA BORDER WILL LIKELY WEAKEN WHEN IT DRIFTS INTO
NORTHER WARREN AND MCKEAN COUNTIES.
&&
.SHORT TERM /7 AM THIS MORNING THROUGH 6 PM TUESDAY/...
THE 04Z RAP IMPLIES THAT THE NEXT CLIPPER WILL LIKELY SPREAD SNOW
ACROSS OUR WESTERN AREAS THIS AFTERNOON...PROBABLY IN SW AREAS
WITHIN 1-2 HOURS OF 2 PM. WITH SNOW OVER MOST OF OUR WESTERN HALF
PROBABLY BY 3PM. IMPLIED BEST RATES WOULD IN THE SOUTHWESTERN
AREAS. THIS IS WILL ALIGNED WITH PREVIOUS FORECASTS.
THE SREF IMPLIES BEST SNOW PROBS AFTER 18Z AND HIGHEST AMOUNTS AND
PROBS IN SOUTHERN TIER COUNTIES. MOST OF THE SNOW IS GONE BY 06Z
TUESDAY AS THE CLIPPER RACES TO THE EAST.
UNDERWHELMING QPF VALUES IN THE 0.1 RANGE IN MOST MEMBERS BUT WITH
20:1 RATIOS COULD BE A GOOD 2 INCHES AND HIGHER END QPFS WOULD
IMPLY UP TO 4 INCHES IN SW MOUNTAINS IS A POSSIBILITY. FLUFFY LOW
WATER SNOW. FARTHER EAST QPF AMOUNTS ARE LOWER SO PROBABLY A
DUSTING TO AN INCH AT BEST. CENTRAL AREAS PROBABLY WILL SEE A
FLUFFY ACCUMULATION GENERALLY UNDER AN INCH.
SREF IS NOT OPTIMISTIC WITH THE 3-5 INCHES IN NW AREAS BUT THIS
COULD BE A MODEL RESOLUTION ISSUE AND DID NOT MESS WITH THIS TOO
MUCH UNTIL WE SEE NEWER GUIDANCE.
STRONG WESTERLY WIND MAXIMUM MOVES OVER SOUTHERN TIER MONDAY
AFTERNOON SO WE COULD BRING DOWN GUSTS IN 15 TO 20 MPH RANGE.
THE WINTER WEATHER ADVISORY FOR THE LAURELS TO 06Z TUESDAY AND
ISSUED A LAKE EFFECT SNOW ADVISORY FOR THE NW MTNS FROM 00Z MONDAY
TO 06Z TUESDAY.
&&
.LONG TERM /TUESDAY NIGHT THROUGH SUNDAY/...
THE LARGER SCALE PATTERN TUESDAY THROUGH SUNDAY SHOWS THE TROUGH
OVER THE EAST WEAKENING AND LIFTING OUT. BY THE WEEKEND THE 500
HPA HEIGHTS SHOULD BE SLIGHTLY ABOVE NORMAL AS WELL AS THE 850 HPA TEMPERATURES.
NORTHERN STREAM SHORT-WAVES COULD BRING PRECIPITATION TUESDAY INTO
EARLY WEDNESDAY...FRIDAY...AND SUNDAY INTO MONDAY. SOME HINTS ARE THAT LOW-
LEVEL COLD AIR COULD BE AN ISSUE WITH WINTRY MIX POSSIBLE IN
NORTHERN REGIONS SHOULD THIS HIGHLY UNCERTAIN WAVE ARRIVE AS
FORECAST LATER THIS WEEKEND.
TUESDAY AFTERNOON INTO EARLY WEDNESDAY SHOULD SEE YET ANOTHER CLIPPER
SYSTEM SPREAD SOME LIGHT SNOW INTO THE AREA DRAGGING SOME COLD AIR
INTO THE REGION. NOT NEARLY AS COLD AS THE PREVIOUS SURGES HAVE
BEEN.
THE QPF VALUES ARE VERY LIGHT...NOT SURPRISING AS THE MAIN
LOW IS CURRENTLY FORECAST TO PASS TO OUR NORTH...VIOLATING ONE OF
THE RULES OF CLIPPERS AND WHERE YOU WANT TO BE TO GET MORE SNOW.
THE SYSTEM DOES DRAG A STRONG SURFACE RIDGE INTO THE REGION WHICH
SUGGESTS THE LOW-LEVEL COLD AIR WILL BE SLOW TO RETREAT ON
THURSDAY AND FRIDAY.
ANOTHER NORTHERN STREAM IMPULSE POSSIBLE IN THE LATE THURSDAY-
FRIDAY TIME-FRAME WITH INDICATIONS OF A LIGHT SNOW EVENT OVER
NORTHERN TIER AREAS. THIS SYSTEM ERODES THE STRONG SURFACE RIDGE A
BIT FRIDAY INTO SATURDAY. THERE ARE HINTS OF POSSIBLE MIXED
PRECIPITATION ISSUES AS GEFS SHOWS POTENTIAL FOR LIGHT FREEZING
RAIN IN CENTRAL AREAS OVER THE RETREATING COLD AIR. MAINLY SNOW
NORTHERN AREAS.
DESPITE THE HIGH HEIGHTS THIS COMING WEEKEND AND THE WARM 850 HPA
TEMPERATURES THE GEFS IMPLIES THE POTENTIAL AT LEAST IN NORTHERN
PA FOR A WINTRY MIX SUNDAY. THE STRONG SURFACE RIDGE IS PRESENT
AGAIN BY SATURDAY AND SUNDAY. GEFS AND CMCEFS SHOW A SORT OF
CLASSIC COLD AIR DAMMING SCENARIO OVER THE WEEKEND.
SO DESPITE THE LARGER SCALE HEIGHT RISES AND WARMER TEMPERATURES
ALOFT BY THE WEEKEND. THE LOW-LEVEL COLD AIR COULD MAKE THE TWO
EXPECTED PRECIPITATION EVENTS A BIT MORE INTERESTING THAN +1 TO
+3C 850 HPA TEMPERATURES WOULD IMPLY. AT THIS TIME MOST OF THE
PRECIPITATION EVENTS...TUEDAYS...FRIDAY AND SUNDAY TIME-FRAME LOOK
A BIT MOISTURE STARVED.
&&
.AVIATION /08Z MONDAY THROUGH FRIDAY/...
COLD FRONT HAS PUSHED EAST OF CENTRAL PA LATE THIS EVENING. A
DRIER WESTERLY FLOW IN THE WAKE OF THE FRONT SHOULD ENSURE VFR
CONDS ACROSS THE SUSQ VALLEY FOR THE REST OF THE NIGHT. OVER THE W
MTNS...RESIDUAL LOW LVL MOISTURE ASCENDING THE HIGH TERRAIN
CONTINUES TO PRODUCE -SN/LOWER VSBYS AT JST AS OF 03Z.
HOWEVER...LOWERING INVERSION HGTS WILL LIKELY CAUSE -SN TO TAPER
OFF AFTER MIDNIGHT. HOWEVER...MDL DATA SUPPORTS A CONTINUATION OF
MVFR STRATOCU OVERNIGHT AT BFD AND JST. IN ADDITION...A TIGHT PRES
GRADIENT BEHIND COLD FRONT WILL RESULT IN A GUSTY WIND OVERNIGHT.
BUFKIT SOUNDING DATA SUPPORTS FREQUENT GUSTS TO ARND 20KTS
OVERNIGHT ACROSS THE W MTNS.
A WEAK LOW PRES SYSTEM TRACKING SOUTH OF PA WILL SPREAD LIGHT
SNOW AND DETERIORATING VSBYS ACROSS MAINLY SOUTHWEST PA MONDAY
AFTN. IFR CONDS APPEAR LIKELY AT JST...WHERE OROGRAPHIC LIFT WILL
ENHANCE THE SNOW...AND POSSIBLE AT AOO.
OUTLOOK...
TUE...EARLY FOG POSSIBLE. LGT SNOW/REDUCED VSBYS POSS LATE.
WED...NO SIG WX EXPECTED.
THU...SNOW POSSIBLE LATE...MAINLY NORTH.
FRI...SNOW POSSIBLE EARLY...MAINLY NORTH.
&&
.CTP WATCHES/WARNINGS/ADVISORIES...
LAKE EFFECT SNOW ADVISORY UNTIL 1 AM EST TUESDAY FOR PAZ004-
005.
WINTER WEATHER ADVISORY UNTIL 1 AM EST TUESDAY FOR PAZ024-033.
&&
$$
SYNOPSIS...GRUMM
NEAR TERM...TYBURSKI
SHORT TERM...GRUMM/LAMBERT
LONG TERM...GRUMM/LAMBERT
AVIATION...FITZGERALD
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
101 AM EST MON FEB 4 2013
.SYNOPSIS...
A DEEP 500 HPA TROUGH OVER EASTERN NORTH AMERICA WILL SLOWLY
WEAKEN AND LIFT OUT AS THE WEEK PROGRESSES. AT LEAST TWO CLIPPER
LIKE WAVES WILL MOVE ACROSS OUR AREA MONDAY AND TUESDAY...AS THIS
HAPPENS. BY THE END OF THE WEEK THE TROUGH AND LOW-LEVEL COLD AIR WILL
BE REPLACED BY A RIDGE AND GENERALLY WARMER AIR. THIS IMPLIES A
GENERAL WARMING TREND AS THE WEEK PROGRESSES AS 850 HPA
TEMPERATURES SHOULD BE ABOUT 1 STANDARD DEVIATION ABOVE NORMAL BY
THE WEEKEND.
&&
.NEAR TERM /UNTIL 7 AM THIS MORNING/...
OBSERVATIONS AND SATELLITE INDICATED MANY LOCATIONS IN SOUTHERN
TIER AND SOUTHEAST HAVE BECOME MOSTLY CLEAR THOUGH PATCHES OF
CLOUDS ARE IMPLIED BY RADAR AND 11-3.9 MICRON DATA. RADAR SHOWS
SOME THIN BANDS OF LIGHT SNOW SHOWERS OVER CENTRAL
MOUNTAINS...MAINLY NEAR AND SOUTH OF THE RADAR.
SNOW SHOWERS ARE MORE PERSISTENT IN SOUTHWEST MOUNTAINS AND CLOSE
TO LAKE ERIE. CLOUDY OVER MOST OF WESTERN PA AND SW MOUNTAINS.
BEST IMPLIED SNOW BANDS ARE NOT IN OUR COUNTY WARNING AREA.
UPDATED CLOUDS AND POPS TO REFLECT CURRENT DATA AND MINOR TWEAKS
TO TEMPERATURES. BEST SNOW PROBS OF COURSE IN SW MOUNTAINS AND
WARREN AND MCKEAN COUNTIES. 13KM RAP SHOWS THE STRONGER BAND JUST
NORTH OF THE PA BORDER WILL LIKELY WEAKEN WHEN IT DRIFTS INTO
NORTHER WARREN AND MCKEAN COUNTIES.
&&
.SHORT TERM /7 AM THIS MORNING THROUGH 6 PM TUESDAY/...
THE 04Z RAP IMPLIES THAT THE NEXT CLIPPER WILL LIKELY SPREAD SNOW
ACROSS OUR WESTERN AREAS THIS AFTERNOON...PROBABLY IN SW AREAS
WITHIN 1-2 HOURS OF 2 PM. WITH SNOW OVER MOST OF OUR WESTERN HALF
PROBABLY BY 3PM. IMPLIED BEST RATES WOULD IN THE SOUTHWESTERN
AREAS. THIS IS WILL ALIGNED WITH PREVIOUS FORECASTS.
THE SREF IMPLIES BEST SNOW PROBS AFTER 18Z AND HIGHEST AMOUNTS AND
PROBS IN SOUTHERN TIER COUNTIES. MOST OF THE SNOW IS GONE BY 06Z
TUESDAY AS THE CLIPPER RACES TO THE EAST.
UNDERWHELMING QPF VALUES IN THE 0.1 RANGE IN MOST MEMBERS BUT WITH
20:1 RATIOS COULD BE A GOOD 2 INCHES AND HIGHER END QPFS WOULD
IMPLY UP TO 4 INCHES IN SW MOUNTAINS IS A POSSIBILITY. FLUFFY LOW
WATER SNOW. FARTHER EAST QPF AMOUNTS ARE LOWER SO PROBABLY A
DUSTING TO AN INCH AT BEST. CENTRAL AREAS PROBABLY WILL SEE A
FLUFFY ACCUMULATION GENERALLY UNDER AN INCH.
SREF IS NOT OPTIMISTIC WITH THE 3-5 INCHES IN NW AREAS BUT THIS
COULD BE A MODEL RESOLUTION ISSUE AND DID NOT MESS WITH THIS TOO
MUCH UNTIL WE SEE NEWER GUIDANCE.
STRONG WESTERLY WIND MAXIMUM MOVES OVER SOUTHERN TIER MONDAY
AFTERNOON SO WE COULD BRING DOWN GUSTS IN 15 TO 20 MPH RANGE.
THE WINTER WEATHER ADVISORY FOR THE LAURELS TO 06Z TUESDAY AND
ISSUED A LAKE EFFECT SNOW ADVISORY FOR THE NW MTNS FROM 00Z MONDAY
TO 06Z TUESDAY.
&&
.LONG TERM /TUESDAY NIGHT THROUGH SUNDAY/...
THE UPCOMING WEEK LOOKS TO BE QUITE ACTIVE...BUT THE 2 OR 3 WEATHER
FEATURES MOVING ESE IN THE FAST FLOW ALOFT DURING THE NEXT SEVERAL
DAYS WILL BE OF THE CLIPPER VARIETY...AND RELATIVELY WEAK AND
MOISTURE STARVED AT THAT.
THROUGH TUESDAY MORNING...EXPECT TO SEE ANOTHER 1-3 INCHES OF
FLUFFY SNOW ACROSS THE WRN MTNS...WITH AROUND AN INCH THROUGHOUT
THE CENTRAL RIDGE AND VALLEY REGION AND SCENT MTNS. THE LOWER AND
MID SUSQ VALLEY WILL LIKELY RECEIVE UNDER AN INCH OF NEW SNOW.
THE SECOND CLIPPER /WITH A PERIOD OF LIGHT SNOW/ SLIDES ACROSS THE
CWA TUESDAY NIGHT. SNOWFALL AMOUNTS WILL BE LIMITED TO JUST A
COATING ACROSS THE SE...WITH AN INCH OR SLIGHTLY MORE OVER THE
CENTRAL AND NW MTNS.
THE UPPER FLOW RELAXES/BECOMES MORE ZONAL FOR THE SECOND HALF OF THE
WEEK WITH A LARGE NORTH/SOUTH RIDGE OF HIGH PRESSURE AT THE SFC
SLIDING EAST FROM THE GLAKES REGION WEDNESDAY...AND BECOMING
CENTERED ACROSS THE COMMONWEALTH WEDNESDAY NIGHT.
A RETURN/SOUTHERLY LLVL FLOW DEVELOPS THURSDAY INTO FRIDAY BRINGING
MODERATING /SLIGHTLY ABOVE NORMAL TEMPS/ IN THE 30S...TO AROUND 40F
IN THE SE.
U.S. AND EC MODELS DIVERGE LATE IN THE WEEK WITH MOST OF THE MEDIUM
RANGE GUIDANCE SHOWING FAIRLY FLAT...NRN AND SRN STREAM SHORT WAVES
MOVING EAST FROM THE MISS VALLEY AND DISPLAYING LITTLE OR NO PHASING
AS THEY MOVE ACROSS THE APPALACHIANS. THE OPERATIONAL 00Z AND 12Z EC
IS THE DISTINCT OUTLIER...INDICATING STRONGER FEATURES IN BOTH THE
NRN AND SRN STREAMS AND SIGNIFICANT PHASING ACROSS THE CENTRAL
APPALACHIANS AND NERN U.S. COMPLETE WITH A DEEPENING NOR`EASTER.
LEANED TWD THE ENVELOPE OF WEAKER SOLUTIONS FOR NOW WITH JUST CHC
POS FOR LIGHT RAIN/SNOW...BUT DIDN/T COMPLETELY IGNORE THE 2
CONSECUTIVE RUNS OF THE EC SUPPORTING THIS SORT OF DEVELOPMENT FOR
VERY LATE IN THE WORK WEEK.
GRADUALLY RISING HEIGHTS OVER THE WEEKEND WILL KEEP DAYTIME TEMPS AT
LEAST SLIGHTLY ABOVE NORMAL WITH POPS LESS THAN 20 PERCENT FOR
SATURDAY INTO EARLY SUNDAY.
A SURGE OF MUCH HIGHER PWATS AND MILDER AIR ALOFT MAY MOVE INTO THE
REGION FROM THE OHIO VALLEY LATE SUNDAY AND MONDAY WITH A CHC OF
RAIN /AND POSSIBLY SOME MIXED PRECIP/. ALTHOUGH THE SPREAD IN LLVL
TEMPS AND DEEP-LAYER MOISTURE INCREASES DRAMATICALLY DURING THE END
OF THE FCST PERIOD /AS ONE WOULD EXPECT WITH THIS TYPE OF SYSTEM
7 DAYS OUT/. PWATS AHEAD OF THIS LAST SYSTEM AVERAGE 12-16MM /JUST
AROUND PLUS 1 SIGMA/...HOWEVER SOME GEFS MEMBERS INDICATE PWATS
CLIMBING AS HIGH AS 20-25MM /PLUS 2-3 SIGMA/ AT THAT TIME.
12Z EC ENSEMBLE MEAN AND THE 12Z OPERATIONAL GFS BOTH SHOW A RATHER
POTENT...SLIGHTLY SUB-1000 MB SFC LOW HEADING NE TWD THE WRN
GLAKES...WHILE THE 12Z GEFS DISPLAYS A MORE ELONGATED N/S TROUGH
WITH PERHAPS A SOUTHERN STREAM LOW STRENGTHENING AS IT MOVES NE FROM
THE LOWER MISS VALLEY. ALL SOLUTIONS SHOW A PUSH OF MILDER/MOIST AIR
WITHIN THE DEEP SWRLY FLOW FOR LATE SUNDAY INTO MONDAY.
&&
.AVIATION /06Z MONDAY THROUGH FRIDAY/...
COLD FRONT HAS PUSHED EAST OF CENTRAL PA LATE THIS EVENING. A
DRIER WESTERLY FLOW IN THE WAKE OF THE FRONT SHOULD ENSURE VFR
CONDS ACROSS THE SUSQ VALLEY FOR THE REST OF THE NIGHT. OVER THE W
MTNS...RESIDUAL LOW LVL MOISTURE ASCENDING THE HIGH TERRAIN
CONTINUES TO PRODUCE -SN/LOWER VSBYS AT JST AS OF 03Z.
HOWEVER...LOWERING INVERSION HGTS WILL LIKELY CAUSE -SN TO TAPER
OFF AFTER MIDNIGHT. HOWEVER...MDL DATA SUPPORTS A CONTINUATION OF
MVFR STRATOCU OVERNIGHT AT BFD AND JST. IN ADDITION...A TIGHT PRES
GRADIENT BEHIND COLD FRONT WILL RESULT IN A GUSTY WIND OVERNIGHT.
BUFKIT SOUNDING DATA SUPPORTS FREQUENT GUSTS TO ARND 20KTS
OVERNIGHT ACROSS THE W MTNS.
A WEAK LOW PRES SYSTEM TRACKING SOUTH OF PA WILL SPREAD LIGHT
SNOW AND DETERIORATING VSBYS ACROSS MAINLY SOUTHWEST PA MONDAY
AFTN. IFR CONDS APPEAR LIKELY AT JST...WHERE OROGRAPHIC LIFT WILL
ENHANCE THE SNOW...AND POSSIBLE AT AOO.
OUTLOOK...
TUE...EARLY FOG POSSIBLE. LGT SNOW/REDUCED VSBYS POSS LATE.
WED...NO SIG WX EXPECTED.
THU...SNOW POSSIBLE LATE...MAINLY NORTH.
FRI...SNOW POSSIBLE EARLY...MAINLY NORTH.
&&
.CTP WATCHES/WARNINGS/ADVISORIES...
LAKE EFFECT SNOW ADVISORY UNTIL 1 AM EST TUESDAY FOR PAZ004-
005.
WINTER WEATHER ADVISORY UNTIL 1 AM EST TUESDAY FOR PAZ024-033.
&&
$$
SYNOPSIS...GRUMM
NEAR TERM...TYBURSKI
SHORT TERM...GRUMM/LAMBERT
LONG TERM...LAMBERT
AVIATION...FITZGERALD
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
1246 AM EST MON FEB 4 2013
.SYNOPSIS...
SEVERAL WEAK DISTURBANCES AT THE SURFACE AND ALOFT WILL RIPPLE
THROUGH THE PERSISTENT NORTHWEST FLOW ACROSS THE REGION INTO THE
MIDDLE OF THE UPCOMING WEEK. THESE WEATHER FEATURES WILL BRING
PERIODS OF MAINLY LIGHT SNOW TO THE REGION...AND LAKE EFFECT SNOW
SHOWERS IN THE NORTHWEST SNOWBELT...OVER THE NEXT SEVERAL DAYS.
TEMPERATURES WILL REMAIN BELOW NORMAL THROUGH TUESDAY...BEFORE
SLOWLY MODERATING TO SLIGHTLY ABOVE NORMAL FOR THE LATTER HALF OF
THE WEEK.
&&
.NEAR TERM /UNTIL 7 AM THIS MORNING/...
OBSERVATIONS AND SATELLITE INDICATED MANY LOCATIONS IN SOUTHERN
TIER AND SOUTHEAST HAVE BECOME MOSTLY CLEAR THOUGH PATCHES OF
CLOUDS ARE IMPLIED BY RADAR AND 11-3.9 MICRON DATA. RADAR SHOWS
SOME THIN BANDS OF LIGHT SNOW SHOWERS OVER CENTRAL
MOUNTAINS...MAINLY NEAR AND SOUTH OF THE RADAR.
SNOW SHOWERS ARE MORE PERSISTENT IN SOUTHWEST MOUNTAINS AND CLOSE
TO LAKE ERIE. CLOUDY OVER MOST OF WESTERN PA AND SW MOUNTAINS.
BEST IMPLIED SNOW BANDS ARE NOT IN OUR COUNTY WARNING AREA.
UPDATED CLOUDS AND POPS TO REFLECT CURRENT DATA AND MINOR TWEAKS
TO TEMPERATURES. BEST SNOW PROBS OF COURSE IN SW MOUNTAINS AND
WARREN AND MCKEAN COUNTIES. 13KM RAP SHOWS THE STRONGER BAND JUST
NORTH OF THE PA BORDER WILL LIKELY WEAKEN WHEN IT DRIFTS INTO
NORTHER WARREN AND MCKEAN COUNTIES.
&&
.SHORT TERM /7 AM THIS MORNING THROUGH 6 PM TUESDAY/...
THE 04Z RAP IMPLIES THAT THE NEXT CLIPPER WILL LIKELY SPREAD SNOW
ACROSS OUR WESTERN AREAS THIS AFTERNOON...PROBABLY IN SW AREAS
WITHIN 1-2 HOURS OF 2 PM. WITH SNOW OVER MOST OF OUR WESTERN HALF
PROBABLY BY 3PM. IMPLIED BEST RATES WOULD IN THE SOUTHWESTERN
AREAS. THIS IS WILL ALIGNED WITH PREVIOUS FORECASTS.
THE SREF IMPLIES BEST SNOW PROBS AFTER 18Z AND HIGHEST AMOUNTS AND
PROBS IN SOUTHERN TIER COUNTIES. MOST OF THE SNOW IS GONE BY 06Z
TUESDAY AS THE CLIPPER RACES TO THE EAST.
UNDERWHELMING QPF VALUES IN THE 0.1 RANGE IN MOST MEMBERS BUT WITH
20:1 RATIOS COULD BE A GOOD 2 INCHES AND HIGHER END QPFS WOULD
IMPLY UP TO 4 INCHES IN SW MOUNTAINS IS A POSSIBILITY. FLUFFY LOW
WATER SNOW. FARTHER EAST QPF AMOUNTS ARE LOWER SO PROBABLY A
DUSTING TO AN INCH AT BEST. CENTRAL AREAS PROBABLY WILL SEE A
FLUFFY ACCUMULATION GENERALLY UNDER AN INCH.
SREF IS NOT OPTIMISTIC WITH THE 3-5 INCHES IN NW AREAS BUT THIS
COULD BE A MODEL RESOLUTION ISSUE AND DID NOT MESS WITH THIS TOO
MUCH UNTIL WE SEE NEWER GUIDANCE.
STRONG WESTERLY WIND MAXIMUM MOVES OVER SOUTHERN TIER MONDAY
AFTERNOON SO WE COULD BRING DOWN GUSTS IN 15 TO 20 MPH RANGE.
THE WINTER WEATHER ADVISORY FOR THE LAURELS TO 06Z TUESDAY AND
ISSUED A LAKE EFFECT SNOW ADVISORY FOR THE NW MTNS FROM 00Z MONDAY
TO 06Z TUESDAY.
&&
.LONG TERM /TUESDAY NIGHT THROUGH SUNDAY/...
THE UPCOMING WEEK LOOKS TO BE QUITE ACTIVE...BUT THE 2 OR 3 WEATHER
FEATURES MOVING ESE IN THE FAST FLOW ALOFT DURING THE NEXT SEVERAL
DAYS WILL BE OF THE CLIPPER VARIETY...AND RELATIVELY WEAK AND
MOISTURE STARVED AT THAT.
THROUGH TUESDAY MORNING...EXPECT TO SEE ANOTHER 1-3 INCHES OF
FLUFFY SNOW ACROSS THE WRN MTNS...WITH AROUND AN INCH THROUGHOUT
THE CENTRAL RIDGE AND VALLEY REGION AND SCENT MTNS. THE LOWER AND
MID SUSQ VALLEY WILL LIKELY RECEIVE UNDER AN INCH OF NEW SNOW.
THE SECOND CLIPPER /WITH A PERIOD OF LIGHT SNOW/ SLIDES ACROSS THE
CWA TUESDAY NIGHT. SNOWFALL AMOUNTS WILL BE LIMITED TO JUST A
COATING ACROSS THE SE...WITH AN INCH OR SLIGHTLY MORE OVER THE
CENTRAL AND NW MTNS.
THE UPPER FLOW RELAXES/BECOMES MORE ZONAL FOR THE SECOND HALF OF THE
WEEK WITH A LARGE NORTH/SOUTH RIDGE OF HIGH PRESSURE AT THE SFC
SLIDING EAST FROM THE GLAKES REGION WEDNESDAY...AND BECOMING
CENTERED ACROSS THE COMMONWEALTH WEDNESDAY NIGHT.
A RETURN/SOUTHERLY LLVL FLOW DEVELOPS THURSDAY INTO FRIDAY BRINGING
MODERATING /SLIGHTLY ABOVE NORMAL TEMPS/ IN THE 30S...TO AROUND 40F
IN THE SE.
U.S. AND EC MODELS DIVERGE LATE IN THE WEEK WITH MOST OF THE MEDIUM
RANGE GUIDANCE SHOWING FAIRLY FLAT...NRN AND SRN STREAM SHORT WAVES
MOVING EAST FROM THE MISS VALLEY AND DISPLAYING LITTLE OR NO PHASING
AS THEY MOVE ACROSS THE APPALACHIANS. THE OPERATIONAL 00Z AND 12Z EC
IS THE DISTINCT OUTLIER...INDICATING STRONGER FEATURES IN BOTH THE
NRN AND SRN STREAMS AND SIGNIFICANT PHASING ACROSS THE CENTRAL
APPALACHIANS AND NERN U.S. COMPLETE WITH A DEEPENING NOR`EASTER.
LEANED TWD THE ENVELOPE OF WEAKER SOLUTIONS FOR NOW WITH JUST CHC
POS FOR LIGHT RAIN/SNOW...BUT DIDN/T COMPLETELY IGNORE THE 2
CONSECUTIVE RUNS OF THE EC SUPPORTING THIS SORT OF DEVELOPMENT FOR
VERY LATE IN THE WORK WEEK.
GRADUALLY RISING HEIGHTS OVER THE WEEKEND WILL KEEP DAYTIME TEMPS AT
LEAST SLIGHTLY ABOVE NORMAL WITH POPS LESS THAN 20 PERCENT FOR
SATURDAY INTO EARLY SUNDAY.
A SURGE OF MUCH HIGHER PWATS AND MILDER AIR ALOFT MAY MOVE INTO THE
REGION FROM THE OHIO VALLEY LATE SUNDAY AND MONDAY WITH A CHC OF
RAIN /AND POSSIBLY SOME MIXED PRECIP/. ALTHOUGH THE SPREAD IN LLVL
TEMPS AND DEEP-LAYER MOISTURE INCREASES DRAMATICALLY DURING THE END
OF THE FCST PERIOD /AS ONE WOULD EXPECT WITH THIS TYPE OF SYSTEM
7 DAYS OUT/. PWATS AHEAD OF THIS LAST SYSTEM AVERAGE 12-16MM /JUST
AROUND PLUS 1 SIGMA/...HOWEVER SOME GEFS MEMBERS INDICATE PWATS
CLIMBING AS HIGH AS 20-25MM /PLUS 2-3 SIGMA/ AT THAT TIME.
12Z EC ENSEMBLE MEAN AND THE 12Z OPERATIONAL GFS BOTH SHOW A RATHER
POTENT...SLIGHTLY SUB-1000 MB SFC LOW HEADING NE TWD THE WRN
GLAKES...WHILE THE 12Z GEFS DISPLAYS A MORE ELONGATED N/S TROUGH
WITH PERHAPS A SOUTHERN STREAM LOW STRENGTHENING AS IT MOVES NE FROM
THE LOWER MISS VALLEY. ALL SOLUTIONS SHOW A PUSH OF MILDER/MOIST AIR
WITHIN THE DEEP SWRLY FLOW FOR LATE SUNDAY INTO MONDAY.
&&
.AVIATION /06Z MONDAY THROUGH FRIDAY/...
COLD FRONT HAS PUSHED EAST OF CENTRAL PA LATE THIS EVENING. A
DRIER WESTERLY FLOW IN THE WAKE OF THE FRONT SHOULD ENSURE VFR
CONDS ACROSS THE SUSQ VALLEY FOR THE REST OF THE NIGHT. OVER THE W
MTNS...RESIDUAL LOW LVL MOISTURE ASCENDING THE HIGH TERRAIN
CONTINUES TO PRODUCE -SN/LOWER VSBYS AT JST AS OF 03Z.
HOWEVER...LOWERING INVERSION HGTS WILL LIKELY CAUSE -SN TO TAPER
OFF AFTER MIDNIGHT. HOWEVER...MDL DATA SUPPORTS A CONTINUATION OF
MVFR STRATOCU OVERNIGHT AT BFD AND JST. IN ADDITION...A TIGHT PRES
GRADIENT BEHIND COLD FRONT WILL RESULT IN A GUSTY WIND OVERNIGHT.
BUFKIT SOUNDING DATA SUPPORTS FREQUENT GUSTS TO ARND 20KTS
OVERNIGHT ACROSS THE W MTNS.
A WEAK LOW PRES SYSTEM TRACKING SOUTH OF PA WILL SPREAD LIGHT
SNOW AND DETERIORATING VSBYS ACROSS MAINLY SOUTHWEST PA MONDAY
AFTN. IFR CONDS APPEAR LIKELY AT JST...WHERE OROGRAPHIC LIFT WILL
ENHANCE THE SNOW...AND POSSIBLE AT AOO.
OUTLOOK...
TUE...EARLY FOG POSSIBLE. LGT SNOW/REDUCED VSBYS POSS LATE.
WED...NO SIG WX EXPECTED.
THU...SNOW POSSIBLE LATE...MAINLY NORTH.
FRI...SNOW POSSIBLE EARLY...MAINLY NORTH.
&&
.CTP WATCHES/WARNINGS/ADVISORIES...
LAKE EFFECT SNOW ADVISORY UNTIL 1 AM EST TUESDAY FOR PAZ004-
005.
WINTER WEATHER ADVISORY UNTIL 1 AM EST TUESDAY FOR PAZ024-033.
&&
$$
SYNOPSIS...LAMBERT/CERU
NEAR TERM...TYBURSKI
SHORT TERM...GRUMM/LAMBERT
LONG TERM...LAMBERT
AVIATION...FITZGERALD
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
308 AM CST MON FEB 4 2013
.SHORT TERM...TODAY THROUGH WEDNESDAY NIGHT
308 AM CST MON FEB 4 2013
FORECAST CONCERNS REMAIN ON SNOW POTENTIAL WITH THE NEXT SHORTWAVE
WAVE TROUGH TO DROP THROUGH THE AREA LATE TONIGHT AND TUESDAY AND
ANOTHER LATE TUESDAY NIGHT INTO WEDNESDAY.
07Z SURFACE ANALYSIS SHOWS AN AREA OF LOW PRESSURE NEAR SIOUX CITY
IOWA. AN AREA OF LIGHT SNOW IS CURRENTLY FOUND EXTENDING FROM
EASTERN MINNESOTA INTO THE SOUTHERN TWO THIRDS OF THE FORECAST AREA.
SNOW RATIOS SO FAR HAVE ONLY BEEN IN THE 10:1 TO 15:1 RANGE WITH 1
TO 2 INCHES OF SNOW SO FAR REPORTED AROUND THE AREA.
04.00Z DETERMINISTIC MODELS OFFER SIMILAR SOLUTIONS FOR THE SYSTEM
TONIGHT...BUT DO SHOW SOME DIFFERENCES WITH THE NEXT SYSTEM WEDNESDAY
AND WEDNESDAY NIGHT. GFS/GEM IN CLOSE AGREEMENT WITH THE TRACK OF
THE SHORTWAVE TROUGH AND QPF AMOUNTS...WHILE THE NAM IS FURTHER
NORTH AND WENT WITH THE NON NAM SOLUTIONS FOR THE TUESDAY
NIGHT/WEDNESDAY SYSTEM.
IN THE NEAR TERM...SHORTWAVE TROUGH WILL EXIT EARLY THIS
MORNING...WITH PERHAPS SOME LINGERING SNOW ACROSS SOUTHWEST
WISCONSIN BETWEEN 12Z-15Z. WILL KEEP ADVISORY IN TACT AND MAYBE
ABLE TO TRIM OFF PORTIONS BEFORE EXPIRATION. OTHERWISE HIGH
PRESSURE SETTLES OVER THE AREA. THE BIGGEST QUESTION WILL BE IF
THERE IS ANY CLEARING. CURRENTLY SKIES ARE CLEAR ACROSS NORTHERN
MINNESOTA AND INTO NORTHWEST WISCONSIN. THIS AREA HAS BEEN
PROGRESSING SOUTHWARD. MODELS SUGGEST THIS CLEARING WILL WORKS ITS
WAY SOUTHWARD INTO THE REGION AND DID TREND CLOUD GRIDS IN THIS
WAY.
FOR TONIGHT INTO TUESDAY...THE NEXT IN THE PARADE OF SHORTWAVE TROUGHS
DROPS SOUTHEAST THROUGH THE AREA. MODELS HAVE BEEN CONSISTENT WITH A
MORE NORTHERLY TRACK THAN THE PREVIOUS SYSTEMS...AFFECTING MAINLY
THE NORTHEASTERN TWO THIRDS OF THE FORECAST AREA. BOTH THE NAM AND
GFS DEPICTING SNOW BEGINNING LATE IN THE EVENING IN ZONE OF
850MB-0700MB WARM ADVECTION AHEAD OF THE MAIN WAVE...WITH THE
DEFORMATION AREA MOVING IN THEN ON TUESDAY. BOTH THE GFS AND NAM
BOTH SHOW SOME WEAK 800BM-900MB FRONTOGENESIS...ESPECIALLY LATE
TONIGHT. GIVEN SOUNDING PROFILES...EXPECT SNOW RATIOS FROM 13:1
SOUTH OF INTERSTATE 90 TO 18:1 ACROSS THE FAR NORTH. THIS WOULD
RESULT IN 1 TO 3 INCHES OF SNOW...WITH THE HIGHER AMOUNTS GENERALLY
ALONG AND NORTH OF INTERSTATE 94. THE SNOW WILL TAPER OFF TUESDAY
AFTERNOON.
QUIET WEATHER EXPECTED TUESDAY NIGHT...BUT ON WEDNESDAY UPPER FLOW
BECOMES MORE ZONAL WITH A WEAK SHORTWAVE TRAVERSING ACROSS NORTHERN
WISCONSIN. WARM ADVECTION AHEAD OF THIS FEATURE MAY RESULT IN ENOUGH
LIFT TO PRODUCE SOME LIGHT SNOW...PRIMARILY ACROSS THE FAR NORTH.
DID CONTINUE THE LOWER END PROBABILITIES AT THIS TIME. THE ASSOCIATED
SURFACE TROUGH PUSHES THROUGH WEDNESDAY NIGHT WITH THE POTENTIAL FOR
SOME LIGHT SNOW...ESPECIALLY ACROSS THE EASTERN COUNTIES.
AS FOR TEMPERATURES...READINGS WILL REMAIN SIMILAR TODAY AS WE HAVE
SEEN THE PAST SEVERAL DAYS...BUT BY TUESDAY AND WEDNESDAY AS UPPER
FLOW BECOMES MORE ZONAL WILL SEE SOME MILDER AIR PUSH INTO THE AREA
WITH HIGHS IN THE UPPER 20S TO LOWER 30S.
.LONG TERM...THURSDAY THROUGH SUNDAY
308 AM CST MON FEB 4 2013
MILDER AIR WILL DOMINATE THIS PERIOD WITH DAYTIME TEMPERATURES
CLIMBING INTO THE LOWER TO MIDDLE 30S EACH DAY. A TROUGH WILL CLEAR
THE AREA THURSDAY WITH LINGERING PRECIPITATION CHANCES. WITH THE
MILDER AIR WILL KEEP A MENTION OF RAIN/SNOW ACROSS THE SOUTHERN HALF
OF THE FORECAST AREA. QUIET WEATHER THEN EXPECTED FROM THURSDAY
NIGHT THROUGH FRIDAY NIGHT. MODEL SOLUTIONS BEGIN TO DIVERGE FOR THE
WEEKEND PERIOD AS MODELS STRUGGLE WITH HANDLING OF THE EVOLUTION OF
A LONG WAVE TROUGH AND CLOSED 500MB ACROSS THE WESTERN CONUS. 04.00Z
ECMWF MORE PROGRESSIVE AS IT PUSHES THIS SYSTEM OUT INTO THE PLAINS
SUNDAY MAINTAINING THE CLOSED LOW. HOWEVER...GFS EVOLVES THIS INTO
AN OPEN WAVE. BROAD SOUTHERLY FLOW AHEAD OF THE SYSTEM WILL PULL
MOISTURE NORTHWARD SPREADING INTO THE AREA SATURDAY THROUGH SUNDAY.
ECMWF HAS BEEN CONSISTENT WITH THIS FEATURE AND DEVELOPS A RATHER
DEEP SURFACE LOW TRACKING IT ACROSS SOUTHERN IOWA SUNDAY NIGHT.
QUESTION WILL BE HOW MUCH WARM AIR GETS PULLED NORTHWARD. 00Z ECMWF
AND GFS SHOW 850MB TEMPERATURES OF +1 TO +2 DEGREES CELSIUS PUSHING
IN SATURDAY AND SUNDAY. THE STRONGER ECMWF TRACKS A PRETTY
SIGNIFICANT BAND OF PRECIPITATION ACROSS THE FORECAST AREA...WHILE
THE GFS KEEPS THE PRECIPITATION SOUTH OF THE AREA. WITH THE MODEL
DIFFERENCES...WILL CONTINUE TO MENTION A CHANCE OF RAIN/SNOW.
&&
.AVIATION...THROUGH 06Z TUESDAY
1124 PM CST SUN FEB 3 2013
THE LIGHT SNOW HAS KEPT CONDITIONS IN THE MVFR CATEGORY TONIGHT AS
SOUNDINGS INDICATE TOO MUCH OF THE COLUMN HAS MOVED OUT OF THE
DENDRITIC GROWTH ZONE. THE HIGHEST RADAR RETURNS HAVE ALREADY
MOVED PAST KRST FOR THE MOST PART. KMPX RADAR STILL SHOWS SOME
HIGHER RETURNS UPSTREAM THAT MAY BRIEFLY HIT KRST WITH SOME LOWER
VISIBILITIES BUT MORE LIKELY TO KEEP THE VISIBILITY DOWN AT KLSE
THROUGH ABOUT 09Z OR SO. AFTER THAT...BOTH SITES SHOULD REMAIN
MVFR UNTIL HIGH PRESSURE BUILDS IN FROM THE NORTH. BOTH THE 04.00Z
NAM AND 04.03Z RAP FORECAST SOUNDINGS INDICATE THE HIGH WILL BRING
ENOUGH DRY AIR TO SCATTER THE CLOUDS OUT BY MID MORNING BUT
CONCERNED ABOUT THE BAND OF MID LEVEL CLOUDS ON THE WEST SIDE OF
THE RIDGE AXIS THAT EXTENDS ALL THE WAY BACK INTO ALBERTA. PRESENT
MOVEMENT WOULD BRING THIS OVER THE AREA SO HAVE GONE TO A HIGH VFR
CEILING MONDAY MORNING INSTEAD OF SCATTERING OUT. THE NEXT SYSTEM
IN THE NORTHWEST FLOW ALOFT WILL START TO ADVANCE TOWARD THE AREA
MONDAY EVENING. THE NAM IS THE QUICKEST TO RETURN LIGHT SNOW TO
THE AREA SUGGESTING BOTH TAF SITES COULD BE DOWN TO MVFR BY
05.06Z. ALL THE OTHER MODELS HOLD THE SNOW OFF UNTIL AFTER 05.06Z
AND WITH NOTHING MORE THAN FLURRIES BEING REPORTED NOW OVER
SASKATCHEWAN INTO ALBERTA WILL GO WITH THE SLOWER SOLUTIONS.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
308 AM CST MON FEB 4 2013
WI...WINTER WEATHER ADVISORY UNTIL 8 AM CST THIS MORNING FOR WIZ032-
033-041-042-053>055-061.
MN...WINTER WEATHER ADVISORY UNTIL 8 AM CST THIS MORNING FOR MNZ079-
086>088-094>096.
IA...WINTER WEATHER ADVISORY UNTIL 8 AM CST THIS MORNING FOR
IAZ009>011-030.
&&
$$
SHORT TERM...RABERDING
LONG TERM...RABERDING
AVIATION...04
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
1125 PM CST SUN FEB 3 2013
.SHORT TERM...TONIGHT THROUGH WEDNESDAY NIGHT
230 PM CST SUN FEB 3 2013
SNOW SNOW AND MORE SNOW. IMPULSES CONTINUE TO MOVE ALONG THE
NORTHWEST FLOW...BRINGING LIGHT SNOW ON A NEARLY EVERYDAY BASIS.
LATEST 88-D IMAGERY AND SFC OBS INDICATE A FRONTOGENETIC BAND OF
LIGHT SNOW MOVING ACROSS SOUTHEAST MN...TRACKING SOUTHEAST TOWARD
NORTHEAST IA/SOUTHWEST WI. THE HRRR IS DOING A DECENT JOB CAPTURING
THIS...ABOUT THE ONLY MESO MODEL THAT IS. IT IS NOT PART OF THE
MAIN SYSTEM AT THE MOMENT...WHICH WILL MOVE IN EARLY THIS EVENING.
STILL...THIS LIGHT SNOW COULD RESULT IN TRACE-COUPLE TENTHS OF AN
INCH OF ACCUMULATION AS IT MOVES ACROSS.
A BAND OF SNOW WILL SLIDE EAST/SOUTHEAST ACROSS THE FORECAST AREA
TONIGHT...AS AN UPPER LEVEL SHORTWAVE TROUGH DRIVES FROM THE
NORTHERN PLAINS TO ACROSS IA BY MONDAY MORNING. RELATIVELY STRONG
SLOPING FRONTOGENETIC RESPONSE ON THE NORTH SIDE OF THE TROUGH/SFC
LOW...WITH SOME -EPV ON THE SOUTHERN PORTIONS OF THIS
LIFT...SUGGESTING THE POTENTIAL FOR ENHANCED BANDING. STRONG 275-290
K ISENTROPIC UPGLIDE WITH A GOOD PUNCH OF QG CONVERGENCE -
ESPECIALLY IN THE 850:700 MB LAYER. MESO MODELS AND NAM/GFS/EC ALL
SUGGEST THERE IS GOING TO BE A NARROW BAND OR SNOW WITH THIS
SYSTEM...
MOSTLY IN THE FRONTOGENETIC REGION. THIS HAS BEEN A CONSISTENT
SIGNAL. NORTH-SOUTH RUNNING TIME/HEIGHT X-SECTIONS SUGGEST THE
DEEPER DENDRITIC GROWTH ZONE WILL BE NORTH OF A RST-KLSE LINE...AWAY
FROM THE STRONGEST LIFT. THE STRONGER LIFT AND POTENTIAL FOR
ENHANCED BANDING COULD OFFSET THE RELATIVELY LOWER RATIOS IN THE
SOUTH. THAT SAID...OVERALL A 20-25:1 RATIO LOOKS REASONABLE...AND
PUTS 3 TO 4 INCHES IN THE FAVORED SNOW AREAS. ISOLATED 5 INCH
AMOUNTS ARE POSSIBLE. EXPANDED THE ADVISORY THIS MORNING...AND WILL
LEAVE AS CURRENTLY CONFIGURED FOR TONIGHT.
WITH A LOT OF PEOPLE OUT AT SUPERBOWL PARTIES...THERE WILL BE A
SIGNIFICANT AMOUNT OF TRAFFIC LATER THIS EVENING. SNOW WILL BE
FALLING AND THERE WILL BE ACCUMULATIONS ON ROADWAYS. CONDITIONS WILL
DETERIORATE AS THE EVENING WEARS ON. THE MORNING COMMUTE WILL ALSO
BE IMPACTED.
MONDAY NIGHT/TUESDAY MORNING DROPS ANOTHER SHORTWAVE TROUGH ACROSS
THE REGION...BUT THIS GO AROUND THE 03.12Z GFS AND NAM FAVOR A BIT
MORE NORTHERN TRACK. FAIRLY CONSISTENT WITH THEIR PREVIOUS RUNS.
DECENT AMOUNT OF QG CONVERGENCE WITH THE SHORTWAVE...ALONG WITH
UPGLIDE ON THE 280-295 K ISENTROPIC SFCS. SOME WEAK FRONTOGENETIC
RESPONSE IN THE 900-800MB ON THE LEADING EDGE OF THE SHORTWAVE. NOT
NEARLY AS DYNAMIC AS THE SYSTEM FOR TONIGHT...BUT PACKS ENOUGH OF A
PUNCH FOR ANOTHER ROUND OF LIGHT SNOW WITH MINOR ACCUMULATIONS.
NAM/GFS BUFKIT SOUNDINGS DON/T INDICATE A VERY DEEP DENDRITIC GROWTH
REGION...WHICH WILL HELP KEEP RATIOS LOWER...AND THUS SNOW AMOUNTS.
15:1 SEEMS REASONABLE AT THIS TIME...WHICH WOULD RESULT IN ABOUT 1-2
INCHES OF ACCUMULATION...MORE LIKELY NORTH/EAST OF THE I-94
CORRIDOR. WHILE AN ADVISORY SHOULD NOT BE NEEDED WITH THIS
SYSTEM...TIMING WOULD RESULT IN LIGHT SNOW FALLING DURING THE
MORNING RUSH.
FINALLY...THE CABOOSE FOR THIS TRAIN OF NORTHWEST SHORTWAVES ARRIVES
WED NIGHT...WITH AGAIN GOOD CONTINUITY BETWEEN THE GFS AND NAM.
COULD BE A COUPLE SHORTWAVES WORKING IN CONCERT DURING THIS
PERIOD...ALONG WITH AN ELEMENT OF MOISTURE RETURN/SOUTHERLY FLOW
AHEAD OF IT. THE GFS AND ECMWF SUGGEST THIS...DEVELOPING QPF IN THIS
REGION...ALONG AN ASSOCIATED SFC FRONT. SNOW RATIOS LOOK MORE IN
THE 15:1 RATIO...AND THE SYSTEM MOVES THROUGH PRETTY QUICK. DON/T
ANTICIPATE MUCH ACCUMULATION AT THIS TIME...GENERALLY UNDER AN
INCH.
.LONG TERM...THURSDAY THROUGH SUNDAY
230 PM CST SUN FEB 3 2013
FINALLY...A BREAK FROM THE NEARLY DAILY SNOW WITH HIGH PRESSURE
BUILDING IN THU NIGHT/FRI. ITS A SHORT LIVED BREAK THOUGH AS THE GFS
AND ECMWF BOTH BRING A STORM SYSTEM OUT OF THE SOUTHWEST AND ACROSS
THE REGION FOR THE WEEKEND. DIFFERENCES CONTINUE WITH THE
STRENGTH...SPEED...AND PLACEMENT OF THE SYSTEM...WHICH ALSO IMPACTS
AMOUNTS. PTYPE WILL ALSO BE A CONCERN AS THERE WILL BE A GOOD SURGE
OF WARMER AIR ON THE EASTERN SIDE OF THE LOW. THE GFS IS THE MORE
AGGRESSIVE WITH ITS AMOUNT OF MOISTURE/QPF AND WARMING. IT HAS A LOT
MORE QPF...ESPECIALLY OUT AHEAD OF THE LOW IN THE MOISTURE
TRANSPORT/WARM AIR ADVECTIVE REGION. BOTH AGREE THERE WILL BE A
DEFORMATION REGION OF SNOW TO THE NORTHWEST OF THE LOW...WITH
SIGNIFICANT AMOUNTS. IT WOULDN/T BE THE FLUFFY...EASY TO MOVE SNOW
EITHER. ITS DEFINITELY A STORM THAT BEARS A CLOSE WATCH.
&&
.AVIATION...THROUGH 06Z TUESDAY
1124 PM CST SUN FEB 3 2013
THE LIGHT SNOW HAS KEPT CONDITIONS IN THE MVFR CATEGORY TONIGHT AS
SOUNDINGS INDICATE TOO MUCH OF THE COLUMN HAS MOVED OUT OF THE
DENDRITIC GROWTH ZONE. THE HIGHEST RADAR RETURNS HAVE ALREADY
MOVED PAST KRST FOR THE MOST PART. KMPX RADAR STILL SHOWS SOME
HIGHER RETURNS UPSTREAM THAT MAY BRIEFLY HIT KRST WITH SOME LOWER
VISIBILITIES BUT MORE LIKELY TO KEEP THE VISIBILITY DOWN AT KLSE
THROUGH ABOUT 09Z OR SO. AFTER THAT...BOTH SITES SHOULD REMAIN
MVFR UNTIL HIGH PRESSURE BUILDS IN FROM THE NORTH. BOTH THE 04.00Z
NAM AND 04.03Z RAP FORECAST SOUNDINGS INDICATE THE HIGH WILL BRING
ENOUGH DRY AIR TO SCATTER THE CLOUDS OUT BY MID MORNING BUT
CONCERNED ABOUT THE BAND OF MID LEVEL CLOUDS ON THE WEST SIDE OF
THE RIDGE AXIS THAT EXTENDS ALL THE WAY BACK INTO ALBERTA. PRESENT
MOVEMENT WOULD BRING THIS OVER THE AREA SO HAVE GONE TO A HIGH VFR
CEILING MONDAY MORNING INSTEAD OF SCATTERING OUT. THE NEXT SYSTEM
IN THE NORTHWEST FLOW ALOFT WILL START TO ADVANCE TOWARD THE AREA
MONDAY EVENING. THE NAM IS THE QUICKEST TO RETURN LIGHT SNOW TO
THE AREA SUGGESTING BOTH TAF SITES COULD BE DOWN TO MVFR BY
05.06Z. ALL THE OTHER MODELS HOLD THE SNOW OFF UNTIL AFTER 05.06Z
AND WITH NOTHING MORE THAN FLURRIES BEING REPORTED NOW OVER
SASKATCHEWAN INTO ALBERTA WILL GO WITH THE SLOWER SOLUTIONS.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
230 PM CST SUN FEB 3 2013
WI...WINTER WEATHER ADVISORY FROM 6 PM THIS EVENING TO 8 AM CST
MONDAY FOR WIZ032-033-041-042-053>055-061.
MN...WINTER WEATHER ADVISORY FROM 6 PM THIS EVENING TO 8 AM CST
MONDAY FOR MNZ079-086>088-094>096.
IA...WINTER WEATHER ADVISORY FROM 6 PM THIS EVENING TO 8 AM CST
MONDAY FOR IAZ009>011-030.
&&
$$
SHORT TERM...RIECK
LONG TERM....RIECK
AVIATION...04
AREA FORECAST DISCUSSION
NWS LINCOLN IL
610 AM CST MON FEB 4 2013
.DISCUSSION...
ISSUED 306 AM CST MON FEB 4 2013
WEAK HIGH PRESSURE SLIDING EAST AS ANOTHER WAVE OF PRECIP MOVES
ACROSS NRN IL THIS MORNING. NOT QUITE OUT OF THE INFLUENCE OF THE
PATTERN JUST YET...THE FIRST COUPLE OF ISSUES FOR THE FORECAST ARE
THE NEXT CLIPPER SYSTEMS MOVING THROUGH THE MIDWEST UNTIL THE END
OF THE WEEK. CONSIDERING THE PATTERN...THE AGREEMENT BTWN THE
MODELS IS IMPRESSIVE. NOT A LOT OF CHANGE IN THE FORECAST OVERALL
AS SOME RUN TO RUN CONSISTENCY IN THE MED AND LONGER RANGE. SOME
MINOR ISSUES IN THE SHORT TERM WITH PRECIP TODAY. ANOTHER ISSUE
FOR AS A RESULT OF THE SERIES OF WAVES MOVING THROUGH...NON
DIURNAL TEMPS FOR A COUPLE OF PERIODS. OVERALL...FORECAST
REMAINING RATHER CONSISTENT.
SHORT TERM...TODAY AND TOMORROW...
SNOW AND ASSOCIATED SHORT WAVE TO THE NORTH THIS MORNING WAS
PREVIOUSLY SET TO COLLIDE WITH ANOTHER WAVE TO THE SOUTH MIDDAY.
HOWEVER...WAVE TO THE NORTH A LITTLE AHEAD OF SCHEDULE...WITH SFC
WAVE TO THE SOUTHWEST LAGGING A BIT BEHIND. HAVE PULLED POPS DOWN
A BIT TO REFLECT THE DROP IN PROBABILITY...KEEPING SLIGHTS IN THIS
MORNING FOR EASTERN HALF OF CWA. BUT THIS AFTERNOON MAY SEE A
BETTER CHANCE WITH THE SOUTHERN WAVE IN THE SE. NAM/ECMWF/GFS
TRENDING A LITTLE DRIER...AND THE RUC IS COMPLETELY DRY THIS
AFTERNOON UNTIL THE WAVE PULLS OUT LATER THIS AFTERNOON. TEMPS A
BIT WARMER TODAY AS WELL WITH A SOUTHERLY COMPONENT RETURNING TO
THE SFC FLOW...ALBEIT WEAK. TOMORROWS WAVE PASSING JUST TO THE
NORTH AND CHANCES FOR PRECIP CONFINED WELL TO THE NORTH
AGAIN...WITH SIMILAR TEMPS TOMORROW AS TODAY...WITH BREEZY
WESTERLY WINDS KEEPING SOME WARM AIR MOVING INTO THE CWA.
LONG TERM...WEDNESDAY THROUGH SUNDAY...
WEDNESDAY DRY AND WARM AGAIN AHEAD OF THE NEXT SYSTEM FOR WED
NIGHT INTO THURSDAY. THOUGH THREAT FROM THE WEST WILL INCREASE FOR
THE OVERNIGHT HOURS ON WED NIGHT...THE BEST CHANCES WILL COME WITH
THE PASSAGE OF THE SFC BOUNDARY ON THUR/THU NIGHT. LAST MODEL RUN
DIVERGES SOMEWHAT WITH THE SOLUTIONS FOR THIS PARTICULAR WAVE. A
TROF DEEPENS OVER THE WEST COAST...AND THIS PARTICULAR SYSTEM IS
A SMALL PIECE OF THE ENERGY EJECTING OUT AHEAD OF THE MAIN TROF.
THE ECMWF IS FAR MORE AMPLIFIED WITH THIS SMALL WAVE...AND THE GFS
IS A BIT LESS SO...WITH A WEAKER BUT MORE DIFFUSE AND SLOWER
PASSAGE OF THE SFC SYSTEM UNTIL IT PASSES ILX FA. CONCERNS FOR THE
SOLUTION DIFFERENCES ARE MINIMAL AT THIS POINT...AS MAJORITY OF
THU AFTERNOON AND INTO THE EVENING ARE RAIN. SOLUTION DIFFERENCES
WILL LIKELY IMPACT QPF AS TIME GETS CLOSER. MAIN ISSUE WITH THIS
SYSTEM AT THIS POINT IS THE CONCERN FOR FZRA IN THE NRN HALF OF
THE CWA WITH THE MORNING PRECIP ON THURSDAY. NEXT SYSTEM OF
INTEREST WILL MOVE INTO THE REGION SAT/SUN CREATING THE POTENTIAL
FOR A MESSY WEEKEND. HOWEVER...THE HANDLING OF THE WAVE/TROF OVER
THE WEST VARIES WIDELY BTWN THE ECMWF AND THE GFS...AND FROM THEIR
PREVIOUS SOLUTIONS...AND WILL KEEP THE MENTION CONSERVATIVE FOR
NOW.
&&
.AVIATION...
ISSUED 610 AM CST MON FEB 4 2013
UPDATED TAFS SHORTLY AFTER 12Z ISSUANCE TO INCLUDE LLWS FOR I-72
SITES. KILX 12Z SOUNDING INDICATES 40KTS AT 1400FT SUGGESTING THAT
MODELS ARE UNDERESTIMATING STRENGTH OF LOW-LEVEL JET AHEAD OF IOWA
SURFACE LOW. JET WILL LIKELY MIX OUT AND WEAKEN BY MIDDLE MORNING
AND WILL ONLY CARRY LLWS UNTIL 16Z.
ORIGINAL 12Z AVIATION AFD...
SURFACE LOW CURRENTLY CENTERED OVER SOUTHEAST IOWA IS EXPECTED TO
TRACK SOUTHEAST ALONG INTERSTATE 74 THROUGH THIS AFTERNOON. LOW
CLOUDS AND PCPN HAS BEEN CONFINED TO LOCATIONS NORTH OF THE
CENTRAL ILLINOIS TERMINALS WITH MID-DECKS IN PLACE. AS LOW MOVES
ACROSS THE AREA...LOW LEVEL MOISTURE WILL LIKELY ADVECT AROUND THE
LOW AND BRING IN MVFR CIGS AND WINDSHIFT TO THE NORTH. THIS SHOULD
OCCUR AT KPIA AND KBMI BY 18Z AND BY 20Z AT KCMI.
OVERNIGHT...WINDS WILL DIMINISH AS SURFACE RIDGING BUILDS INTO
ILLINOIS. THOUGH DEEP MOISTURE WILL LIKELY BE PUSHED EAST OF THE
AREA...HIGH BOUNDARY LAYER MOISTURE TRAPPED BELOW THE SUBSIDENCE
WILL LIKELY BE SUFFICIENT TO KEEP MVFR...AND ISOLATED IFR...CIGS
IN PLACE.
BARKER
&&
.ILX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS LINCOLN IL
526 AM CST MON FEB 4 2013
.DISCUSSION...
ISSUED 306 AM CST MON FEB 4 2013
WEAK HIGH PRESSURE SLIDING EAST AS ANOTHER WAVE OF PRECIP MOVES
ACROSS NRN IL THIS MORNING. NOT QUITE OUT OF THE INFLUENCE OF THE
PATTERN JUST YET...THE FIRST COUPLE OF ISSUES FOR THE FORECAST ARE
THE NEXT CLIPPER SYSTEMS MOVING THROUGH THE MIDWEST UNTIL THE END
OF THE WEEK. CONSIDERING THE PATTERN...THE AGREEMENT BTWN THE
MODELS IS IMPRESSIVE. NOT A LOT OF CHANGE IN THE FORECAST OVERALL
AS SOME RUN TO RUN CONSISTENCY IN THE MED AND LONGER RANGE. SOME
MINOR ISSUES IN THE SHORT TERM WITH PRECIP TODAY. ANOTHER ISSUE
FOR AS A RESULT OF THE SERIES OF WAVES MOVING THROUGH...NON
DIURNAL TEMPS FOR A COUPLE OF PERIODS. OVERALL...FORECAST
REMAINING RATHER CONSISTENT.
SHORT TERM...TODAY AND TOMORROW...
SNOW AND ASSOCIATED SHORT WAVE TO THE NORTH THIS MORNING WAS
PREVIOUSLY SET TO COLLIDE WITH ANOTHER WAVE TO THE SOUTH MIDDAY.
HOWEVER...WAVE TO THE NORTH A LITTLE AHEAD OF SCHEDULE...WITH SFC
WAVE TO THE SOUTHWEST LAGGING A BIT BEHIND. HAVE PULLED POPS DOWN
A BIT TO REFLECT THE DROP IN PROBABILITY...KEEPING SLIGHTS IN THIS
MORNING FOR EASTERN HALF OF CWA. BUT THIS AFTERNOON MAY SEE A
BETTER CHANCE WITH THE SOUTHERN WAVE IN THE SE. NAM/ECMWF/GFS
TRENDING A LITTLE DRIER...AND THE RUC IS COMPLETELY DRY THIS
AFTERNOON UNTIL THE WAVE PULLS OUT LATER THIS AFTERNOON. TEMPS A
BIT WARMER TODAY AS WELL WITH A SOUTHERLY COMPONENT RETURNING TO
THE SFC FLOW...ALBEIT WEAK. TOMORROWS WAVE PASSING JUST TO THE
NORTH AND CHANCES FOR PRECIP CONFINED WELL TO THE NORTH
AGAIN...WITH SIMILAR TEMPS TOMORROW AS TODAY...WITH BREEZY
WESTERLY WINDS KEEPING SOME WARM AIR MOVING INTO THE CWA.
LONG TERM...WEDNESDAY THROUGH SUNDAY...
WEDNESDAY DRY AND WARM AGAIN AHEAD OF THE NEXT SYSTEM FOR WED
NIGHT INTO THURSDAY. THOUGH THREAT FROM THE WEST WILL INCREASE FOR
THE OVERNIGHT HOURS ON WED NIGHT...THE BEST CHANCES WILL COME WITH
THE PASSAGE OF THE SFC BOUNDARY ON THUR/THU NIGHT. LAST MODEL RUN
DIVERGES SOMEWHAT WITH THE SOLUTIONS FOR THIS PARTICULAR WAVE. A
TROF DEEPENS OVER THE WEST COAST...AND THIS PARTICULAR SYSTEM IS
A SMALL PIECE OF THE ENERGY EJECTING OUT AHEAD OF THE MAIN TROF.
THE ECMWF IS FAR MORE AMPLIFIED WITH THIS SMALL WAVE...AND THE GFS
IS A BIT LESS SO...WITH A WEAKER BUT MORE DIFFUSE AND SLOWER
PASSAGE OF THE SFC SYSTEM UNTIL IT PASSES ILX FA. CONCERNS FOR THE
SOLUTION DIFFERENCES ARE MINIMAL AT THIS POINT...AS MAJORITY OF
THU AFTERNOON AND INTO THE EVENING ARE RAIN. SOLUTION DIFFERENCES
WILL LIKELY IMPACT QPF AS TIME GETS CLOSER. MAIN ISSUE WITH THIS
SYSTEM AT THIS POINT IS THE CONCERN FOR FZRA IN THE NRN HALF OF
THE CWA WITH THE MORNING PRECIP ON THURSDAY. NEXT SYSTEM OF
INTEREST WILL MOVE INTO THE REGION SAT/SUN CREATING THE POTENTIAL
FOR A MESSY WEEKEND. HOWEVER...THE HANDLING OF THE WAVE/TROF OVER
THE WEST VARIES WIDELY BTWN THE ECMWF AND THE GFS...AND FROM THEIR
PREVIOUS SOLUTIONS...AND WILL KEEP THE MENTION CONSERVATIVE FOR
NOW.
&&
.AVIATION...
ISSUED 526 AM CST MON FEB 4 2013
SURFACE LOW CURRENTLY CENTERED OVER SOUTHEAST IOWA IS EXPECTED TO
TRACK SOUTHEAST ALONG INTERSTATE 74 THROUGH THIS AFTERNOON. LOW
CLOUDS AND PCPN HAS BEEN CONFINED TO LOCATIONS NORTH OF THE
CENTRAL ILLINOIS TERMINALS WITH MID-DECKS IN PLACE. AS LOW MOVES
ACROSS THE AREA...LOW LEVEL MOISTURE WILL LIKELY ADVECT AROUND THE
LOW AND BRING IN MVFR CIGS AND WINDSHIFT TO THE NORTH. THIS SHOULD
OCCUR AT KPIA AND KBMI BY 18Z AND BY 20Z AT KCMI.
OVERNIGHT...WINDS WILL DIMINISH AS SURFACE RIDGING BUILDS INTO
ILLINOIS. THOUGH DEEP MOISTURE WILL LIKELY BE PUSHED EAST OF THE
AREA...HIGH BOUNDARY LAYER MOISTURE TRAPPED BELOW THE SUBSIDENCE
WILL LIKELY BE SUFFICIENT TO KEEP MVFR...AND ISOLATED IFR...CIGS
IN PLACE.
BARKER
&&
.ILX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS TOPEKA KS
531 AM CST MON FEB 4 2013
...UPDATE TO AVIATION...
.DISCUSSION...
INVERTED SURFACE TROF BISECTING THE FORECAST AREA THIS
MORNING...WITH COLDER AIR STILL TO THE NORTH AT THIS HOUR. UPPER
WAVE MOVING THROUGH NORTHWEST KANSAS TO THE SOUTHEAST AND WILL SWEEP
COLD FRONT ACROSS THE FORECAST AREA THROUGH THE DAY TODAY.
TEMPERATURES EXPECTED TO STAY WELL MIXED INTO THE 40S FOR THE EAST
CENTRAL COUNTIES UNTIL THIS AFTERNOON WHEN FRONT COMES
THROUGH...WITH NORTH CENTRAL COUNTIES STARTING OFF IN THE LOW TO
MIDDLE 30S BUT DROPPING SLOWLY AS THE DAY GOES ON.
ALSO KEEPING AN EYE ON THE CLOUD DECK MOVING QUICKLY SOUTH OUT OF
SOUTH DAKOTA AND NORTHEAST NEBRASKA. RAP RH CHARTS BRING THIS DECK
INTO THE I70 CORRIDOR AROUND THE NOON HOUR BEFORE BREAKING UP AS IT
MOVES SOUTHWARD. FAR NORTHEAST COUNTIES EXPECTED TO REMAIN THE
COOLEST WITH TEMPERATURES IN THE MIDDLE 30S AND FALLING THIS
AFTERNOON. WINDS BECOME BREEZY FROM THE NORTH FOR A TIME AS THE
FRONT PUSHES THROUGH...BUT THEN WINDS LIGHTEN AND VEER AROUND TO THE
SOUTHWEST BY EARLY MORNING HOURS. OVERNIGHT LOWS SHOULD DROP INTO
THE 20S MOST AREAS AS THE WINDS DIMINISH AND CLOUDS DECREASE.
67
TUESDAY AND WEDNESDAY...ANOTHER WEAK COLD FRONT WILL PUSH THROUGH
TUESDAY AS NORTHWEST FLOW CONTINUES ALOFT. SURFACE HIGH PRESSURE
MOVES RAPIDLY EAST TUESDAY NIGHT ALLOWING WAA TO ONCE AGAIN
RETURN. HOWEVER...WAA NOT STRONG INITIALLY ON WEDNESDAY AFTERNOON
WITH ONLY A MODEST INCREASE IN 850MB TEMPS OF ABOUT 2-3C AND A
3-4DM INCREASE IN HEIGHTS. 925MB-850MB TRANSPORT WINDS WILL BE
AROUND 20-25KTS FROM THE SOUTH/SOUTHEAST...AND WILL ADVECT A
DECENT MOISTURE PLUME NORTH INTO THE CWA AHEAD OF ANOTHER
ADVANCING COLD FRONT FOR WEDNESDAY NIGHT AND INTO THURSDAY
MORNING. WEDNESDAY LOOKS TO BE THE WARMEST DAY OF THE WEEK WITH
HIGHS APPROACHING OR TOPPING 60.
WEDNESDAY NIGHT AND THURSDAY...PW VALUES INCREASE TO AROUND AN
INCH FOR LATE WEDNESDAY NIGHT FOR AREAS MAINLY SOUTH OF INTERSTATE
70. INCREASED POPS AS MODELS COMING INTO AGREEMENT AS FAR AS
PLACEMENT. HOWEVER...MODELS DO DIVERGE ON QPF WITH THE NAM BEING
VERY AGGRESSIVE WITH A BULLS EYE OVER THE SOUTHERN PORTION OF THE
CWA OF AN INCH OF PRECIP. FEEL THIS IS A BIT OVERDONE...AND HAVE
GONE WITH THE MORE CONSISTENT AND CONSERVATIVE QPF VALUES OF THE
ECMWF AND GFS. NAM QUITE AGGRESSIVE ON MUCAPE VALUES AS WELL WITH
UP TO 500 J/KG. MENTIONED ISOLATED THUNDER WEDNESDAY NIGHT SOUTH
OF INTERSTATE 70...BUT FEEL THE NAM INSTABILITY VALUES A BIT
INFLATED. SHEAR PROFILES LOOK TO SUPPORT THUNDER AS WELL WITH
0-6KM VALUES OF AROUND 40KTS. THE SYSTEM SHOULD CLEAR THE CWA BY
18Z. TEMPERATURES WILL BE SLIGHTLY COOLER BEHIND THE FRONT OF
AROUND 10 DEGREES...AND WITH SKIES CLEARING OUT QUICKLY...SHOULD
SEE A RETURN TO 40`S AND 50`S BY THURSDAY AFTERNOON.
EXTENDED...(THURSDAY NIGHT THROUGH THE WEEKEND)...NEXT SYSTEM TO
AFFECT THE REGION WILL BE SATURDAY. QUITE A BIT OF DIVERGENCE IN
THE MODELS AT THIS TIME AS TO THE EVOLUTION OF THE SYSTEM AND ITS
IMPACT ON THE PLAINS. THE GFS ESSENTIALLY HAS THE SYSTEM BECOME
CUTOFF OVER THE DESERT SOUTHWEST AS THE NORTHERN STREAM OF THE
JET PINCHES IT OFF OVER THAT REGION OF THE COUNTRY WITH A FAST
MOVING SHRTWV ACROSS THE NORTHERN PLAINS. THE ECMWF HAS THE SYSTEM
MOVE RAPIDLY OUT OF THE DESERT SOUTHWEST AS A CLOSED H5 LOW RIGHT
ACROSS KANSAS. GIVEN THE EVOLUTION OF SYSTEMS THIS PAST WINTER
SEASON...FEEL THE ECMWF SCENARIO NOT LIKELY. HOWEVER...LOWERED
POPS A BIT SATURDAY TO REFLECT THE DISAGREEMENT IN MODELS. BEHIND
THE SYSTEM...PROFILES LOOK COLD ENOUGH TO BEGIN SUPPORTING SLEET
OR SNOW OVER THE NORTHWEST COUNTIES BY SUNDAY AFTERNOON.
01
&&
.AVIATION...
MAINLY A WIND FORECAST THROUGH THE PERIOD. FRONT APPROACHING TAF
SITES AND WILL BRING INCREASING NORTH WINDS INTO THE AFTERNOON.
WILL NEED TO KEEP AN EYE ON MVFR DECK OVER NEBRASKA AS EXPECT WILL
BREAK UP AS IT MOVES SOUTH. WINDS BECOME LIGHT AND VARIABLE LATER
THIS EVENING INTO THE OVERNIGHT HOURS. 67
&&
.TOP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS GRAND RAPIDS MI
1033 AM EST MON FEB 4 2013
.SYNOPSIS...
ISSUED AT 343 AM EST MON FEB 4 2013
LIGHT SNOW WILL CONTINUE INTO THE AFTERNOON TODAY AS A A CLIPPER
MOVES BY TO THE SOUTH OF THE CWA. AN INCH OR TWO OF ADDITIONAL
ACCUMULATION IS POSSIBLE TODAY BEFORE THE SNOW DIMINISHES. A
STRONGER CLIPPER WILL MOVE ACROSS THE CWA TUESDAY RESULTING IN
ANOTHER 1 TO 4 INCHES OF SNOW. MODERATING TEMPERATURES TOWARD THE
END OF THE WEEK MAY RESULT IN MIXED RAIN AND SNOW OVER THE WEEKEND.
&&
.UPDATE...
ISSUED AT 1032 AM EST MON FEB 4 2013
MY CURRENT THINKING IS TO DROP THE LAKE EFFECT SNOW ADVISORY AT 1
PM WITH THE WINTER WEATHER ADVISORY SINCE SURFACE WINDS WILL BE
FROM THE NORTH NORTHEAST... THAT IS NOT SUPPORTIVE OF LAKE EFFECT
SNOW. ALSO THE LATEST RAP MODEL DATA SHOWS LITTLE IF ANY LIFT
ALONG THE LAKE SHORE THIS AFTERNOON AS WELL AS LITTLE IF ANY QPF.
SO ONCE THE SYNOPTIC SYSTEM EXITS IN EARLY THIS AFTERNOON THE SHOW
IS OVER FOR THIS EVENT.
IT LOOKS TO ME LIKE TOMORROW WE WILL HAVE A SW FLOW ENHANCED EVENT
WITH THE NW LAKE SHORE AREAS GETTING THE MOST SNOW. SINCE I DO NOT
WANT HEADLINES FOR TODAY`S EVENT MIXED WITH TOMORROW I PLAN ON
PUTTING THE LAKE EFFECT SNOW ADVISORY (MKG TO LDM ONE ROW OF
COUNTIES) OUT WITH THE 4 PM FORECAST.
&&
.SHORT TERM...(TODAY THROUGH WEDNESDAY)
ISSUED AT 343 AM EST MON FEB 4 2013
FORECAST CONCERNS DEAL WITH SNOW TRENDS TODAY AND TUESDAY.
REGIONAL RADAR SHOWS SNOW FALLING ACROSS THE SRN CWA WNWWD ACROSS
SRN
WISCONSIN. ANOTHER INCH OR TWO OF ACCUMULATION IS POSSIBLE AS THE
SYSTEM PASSES BY. LOWEST CONDENSATION PRESSURE DEFICITS ARE SOUTH OF
I-96 TODAY WHICH IS WHERE WE HAVE THE GREATEST ACCUMULATION. AS THE
CLIPPER PASSES BY SNOW WILL TAPER THIS AFTERNOON. THE SYNOPTIC SNOW
IS GETTING A BOOST FROM THE WESTERLY WIND OFF THE LAKE.
WE MAY SEE A 6 OR 8 HR BREAK FROM SNOW BEFORE THE NEXT CLIPPER
ARRIVES LATE TONIGHT. THE CLIPPER IS PROGD MOVE OVER THE CWA TUESDAY
RESULTING IN A 1-3/2-4 INCH TYPE EVENT. THE LIGHT WINDS EXPECTED
TODAY SHOULD RESULT IN A LOWER IMPACT EVENT. DRY WX EXPECTED
WEDNESDAY AS ZONAL FLOW DEVELOPS IN THE WAKE OF THE CLIPPER.
.LONG TERM...(WEDNESDAY NIGHT THROUGH SUNDAY)
ISSUED AT 343 AM EST MON FEB 4 2013
ZONAL FLOW STILL LOOKS TO BE THE PREDOMINATE UPPER PATTERN TYPE
THROUGH THE LONG TERM PERIOD. MAIN FEATURES TO KEY ON ARE A
SHORTWAVE TROUGH FORECAST TO SWING THROUGH THE GREAT LAKES THURSDAY
AND ANOTHER DEEPER TROUGH CENTERED AROUND SUNDAY. 850MB ARE FORECAST
TO BE BETWEEN -8C AND +4C MUCH OF THE LONG TERM WHICH WILL TAKE LAKE
EFFECT OUT OF PLAY...WHICH WILL BE A CHANGE FROM THE CURRENT AND
RECENT PAST. TEMPERATURES THROUGH THE PERIOD WILL BE NEAR TO ABOVE
NORMAL.
AS FOR THE DETAILS...HAVE A CHANCE OF SNOW MENTIONED WEDNESDAY NIGHT
AHEAD OF A SURFACE TROUGH. HAVE TRENDED POPS TO LIKELY FOR THE BULK
OF THE CWA ON THURSDAY. MAINTAINED A POSSIBLE MIX WITH RAIN IN THE
SOUTH AS 850MB TEMPS TRY TO FLIRT WITH +2C PER THE ECMWF. THE SYSTEM
MOVES EAST THURSDAY NIGHT TAKING THE PRECIPITATION WITH IT. DRY
WEATHER IS ANTICIPATED FOR FRIDAY THROUGH SATURDAY NIGHT AS HIGH
PRESSURE SLIDES THROUGH THE REGION.
THE SUNDAY SYSTEM IS ASSOCIATED WITH UPPER SOUTHWEST FLOW IN PLACE.
THE ECMWF HAS MORE OF A SOUTHERN STREAM LOW EJECTING OUR DIRECTION.
AT THIS POINT HAVE RAIN AND SNOW MENTIONED. IT APPEARS SUNDAY MAY BE
TRENDING TOWARD A COLD RAIN. GIVEN THE TIME FRAME THOUGH...DEEP INTO
THE LONG TERM...WILL MAINTAIN A MIX AS THE ZERO C 850MB ISOTHERM IS
IN THE CWA PER BOTH THE GFS AND THE ECMWF.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z TUESDAY MORNING)
ISSUED AT 659 AM EST MON FEB 4 2013
A SWATH OF SNOW IS MOVING THROUGH SOUTHWEST LOWER MICHIGAN THIS
MORNING ASSOCIATED WITH A CLIPPER SYSTEM AND ENHANCED BY THE LAKE.
THE WORST OF THE CONDITIONS SHOULD OCCUR IN THE FIRST SEVERAL HOURS
OF THIS TAF CYCLE...12Z TO 16Z. KAZO...KGRR...KBTL AND KJXN WILL
BE THE MOST IMPACTED AS THE SYSTEM SLIDES TO THE SOUTHEAST THROUGH
THE REGION. IFR CONDITIONS WILL BE LIKELY AT THE AFOREMENTIONED
SITES THIS MORNING. AN IMPROVEMENT SHOULD OCCUR FROM WEST TO EAST
DURING THE AFTERNOON HOURS...WITH CONDITIONS LIFTING TO MVFR OR
EVEN VFR. MUCH OF TONIGHT WILL BE QUIET BEFORE THE NEXT QUICK
HITTING CLIPPER MOVES IN TUESDAY MORNING.
&&
.MARINE...
ISSUED AT 343 AM EST MON FEB 4 2013
DISCONTINUED THE SCA AS WINDS AND WAVES ARE LIKELY BELOW CRITERIA.
&&
.HYDROLOGY...
ISSUED AT 343 AM EST MON FEB 4 2013
WARMER WX IS EXPECTED TOWARD THE END OF THE WEEK. THIS MAY
EXACERBATE THE ICE JAM POTENTIAL.
&&
.GRR WATCHES/WARNINGS/ADVISORIES...
MI...WINTER WEATHER ADVISORY UNTIL 1 PM EST THIS AFTERNOON FOR MIZ073-
074.
LAKE EFFECT SNOW ADVISORY UNTIL 7 PM EST THIS EVENING FOR MIZ056-
064-071-072.
LM...NONE.
&&
$$
UPDATE...WDM
SYNOPSIS...93
SHORT TERM...93
LONG TERM...DUKE
AVIATION...DUKE
HYDROLOGY...93
MARINE...93
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
707 AM EST MON FEB 4 2013
.SYNOPSIS...
A DEEP 500 HPA TROUGH OVER EASTERN NORTH AMERICA WILL SLOWLY
WEAKEN AND LIFT OUT AS THE WEEK PROGRESSES. AT LEAST TWO CLIPPER
LIKE WAVES WILL MOVE ACROSS OUR AREA MONDAY AND TUESDAY...AS THIS
HAPPENS. BY THE END OF THE WEEK THE TROUGH AND LOW-LEVEL COLD AIR WILL
BE REPLACED BY A RIDGE AND GENERALLY WARMER AIR. THIS IMPLIES A
GENERAL WARMING TREND AS THE WEEK PROGRESSES AS 850 HPA
TEMPERATURES SHOULD BE ABOUT 1 STANDARD DEVIATION ABOVE NORMAL BY
THE WEEKEND.
&&
.NEAR TERM /UNTIL 10 AM THIS MORNING/...
RADAR STILL SHOWS NARROW BANDS OF LIGHT SNOW OVER CENTRAL PA WHICH
DO NOT EXTEND MUCH BEYOND THE RIDGE VALLEY SYSTEM. NO REPORTS OF
ANY SIGNIFICANT SNOWS. BEST SNOW AREAS APPEAR JUST NORTH OF NY/PA
BORDER AND SW MTS WERE OBSERVATIONS AND RADAR SHOWED MORE
CONSISTENT SNOWS. SATELLITE IMAGERY SEEMS TO SHOW THE CLOUDS
COVERING MOSTLY WESTERN HALF TO ABOUT TWO THIRDS OF THE STATE. HAS
BEEN MOSTLY CLEAR IN SOME OF SOUTHEASTERN AREAS.
THE CIRRUS WITH THE APPROACHING CLIPPER HAS MOVED OVER MOST OF
OHIO AND SHOULD BE IN PA WITHIN HOURS. AFTERNOON SNOW IS GETTING CLOSER.
TEMPERATURES MAINLY IN THE TEENS AND TWENTIES ACROSS THE REGION
THIS MORNING WITH STEADY WEST WINDS. SHOULD SEE SLOW RISE IN TEMPS
THIS AM AND STEADILY INCREASING CLOUDS...THOUGH MOSTLY CLOUDY IN
WEST WITH ALL THE LOW CLOUDS.
&&
.SHORT TERM /10 AM THIS MORNING THROUGH 6 PM TUESDAY/...
THE CLOUDS FROM THE CLIPPER ARE CLEARLY ZIPPING ACROSS OHIO THIS
MORNING AND HEADED OUR WAY FAST. TIMING LOOKS GOOD AND CONSISTENT
WITH RAP AND 06Z NAM CLOSE TO PREVIOUS FORECASTS OF 03Z SREF.
EXPECT SNOW TO ARRIVE AN HOUR OF ABOUT 2 PM IN THE WEST.
ONLY RUB IS THE 06Z NAM IMPLIES THERE COULD BE SOME SPOTTY 0.4 TO
0.50 INCH QPF VALUES IN EXTREME SW PA. A FEW HIGHER ELEVATIONS
SITES WITH 16 TO 20:1 RATIOS COULD SEE OVER 6 INCHES OF SNOW.
THOUGH MOST LOCATIONS SHOULD BE IN THE MORE GENERAL 3-5 RANGE. SO
DID NOT PUT UP A WINTER STORM WARNING FOR WHAT MIGHT BE HEAVY SNOW
ON HIGHER RIDGES OF SOMERSET COUNTY. BUT THERE COULD BE SOME
ISOLATED AMOUNTS AROUND OR JUST OVER 6 INCHES.
PREVIOUS DISCUSSION STILL VALID:
THE LATEST HIGH RESOLUTION MODELS ALL IMPLY A BRIEF PERIOD OF PERHAPS
MODERATE SNOW IN THE SW AREAS NEAR THE MD BORDER. THE 03Z SREF TOO
SUPPORTS THIS CONCEPT WITH SNOW ARRIVING A FEW HOURS EITHER SIDE
OF ABOUT 2 PM IN WESTERN PA. THE SREF IMPLIES 0.1 TO 0.20 INCHES
OF QPF IN SW MOUNTAINS WHICH WOULD BE A GOOD 4-5 INCHES OF VERY
FLUFFY SNOW. THE SREF MEAN IMPLIES ISOLATED 0.30 AREAS FOR STORM
TOTALS IN SOMERSET COUNTY. THE AXIS OF HIGHEST POPS AND HIGHEST
QPFS RUN ALONG THE PA/MD BORDER AND SOUTH. THOUGH BEST QPF IN OUR
AREA ARE IN SW MTS.
INDICATIONS ARE MOST OF THE SYNOPTIC SNOWS WILL END QUICKLY
BETWEEN 10 PM AND 1 AM TONIGHT. SHOWED SNOW AMOUNTS RAPIDLY
LOWERING TO NORTH WITH EVENT AND SNOW:WATER RATIOS IN THE 16 TO
20:1 RANGE.
SREF IS NOT OPTIMISTIC WITH THE 3-5 INCHES IN NW AREAS BUT THIS
COULD BE A MODEL RESOLUTION ISSUE AND DID NOT MESS WITH THIS TOO
MUCH UNTIL WE SEE NEWER GUIDANCE.
STRONG WESTERLY WIND MAXIMUM MOVES OVER SOUTHERN TIER MONDAY
AFTERNOON SO WE COULD BRING DOWN GUSTS IN 15 TO 20 MPH RANGE.
THE WINTER WEATHER ADVISORY FOR THE LAURELS TO 06Z TUESDAY AND
ISSUED A LAKE EFFECT SNOW ADVISORY FOR THE NW MTNS FROM 00Z MONDAY
TO 06Z TUESDAY.
THE NEXT WAVE SHOULD NOT ARRIVE UNTIL TUESDAY AFTERNOON OR EVENING
WITH ANOTHER SHOT AT SOME ACCUMULATING SNOWS OF 1-2 INCHES IN
NORTHERN TIER OF MORE FLUFFY SNOWS.
&&
.LONG TERM /TUESDAY NIGHT THROUGH SUNDAY/...
THE SECOND CLIPPER WILL BRING SNOW (SEE ABOVE) TO THE REGION
MAINLY LATE TUESDAY AFTERNOON INTO TUESDAY NIGHT. BEST CHANCE OF
1-2 INCHES OF SNOW SHOULD BE ACROSS NORTHERN AREAS.
PREVIOUS DISCUSSION...THE LARGER SCALE PATTERN TUESDAY THROUGH
SUNDAY SHOWS THE TROUGH OVER THE EAST WEAKENING AND LIFTING OUT.
BY THE WEEKEND THE 500 HPA HEIGHTS SHOULD BE SLIGHTLY ABOVE NORMAL
AS WELL AS THE 850 HPA TEMPERATURES. NORTHERN STREAM SHORT-WAVES
COULD BRING PRECIPITATION TUESDAY INTO EARLY
WEDNESDAY...FRIDAY...AND SUNDAY INTO MONDAY. SOME HINTS ARE THAT
LOW- LEVEL COLD AIR COULD BE AN ISSUE WITH WINTRY MIX POSSIBLE IN
NORTHERN REGIONS SHOULD THIS HIGHLY UNCERTAIN WAVE ARRIVE AS
FORECAST LATER THIS WEEKEND.
TUESDAY AFTERNOON INTO EARLY WEDNESDAY SHOULD SEE YET ANOTHER CLIPPER
SYSTEM SPREAD SOME LIGHT SNOW INTO THE AREA DRAGGING SOME COLD AIR
INTO THE REGION. NOT NEARLY AS COLD AS THE PREVIOUS SURGES HAVE
BEEN.
THE QPF VALUES ARE VERY LIGHT...NOT SURPRISING AS THE MAIN
LOW IS CURRENTLY FORECAST TO PASS TO OUR NORTH...VIOLATING ONE OF
THE RULES OF CLIPPERS AND WHERE YOU WANT TO BE TO GET MORE SNOW.
THE SYSTEM DOES DRAG A STRONG SURFACE RIDGE INTO THE REGION WHICH
SUGGESTS THE LOW-LEVEL COLD AIR WILL BE SLOW TO RETREAT ON
THURSDAY AND FRIDAY.
ANOTHER NORTHERN STREAM IMPULSE POSSIBLE IN THE LATE THURSDAY-
FRIDAY TIME-FRAME WITH INDICATIONS OF A LIGHT SNOW EVENT OVER
NORTHERN TIER AREAS. THIS SYSTEM ERODES THE STRONG SURFACE RIDGE A
BIT FRIDAY INTO SATURDAY. THERE ARE HINTS OF POSSIBLE MIXED
PRECIPITATION ISSUES AS GEFS SHOWS POTENTIAL FOR LIGHT FREEZING
RAIN IN CENTRAL AREAS OVER THE RETREATING COLD AIR. MAINLY SNOW
NORTHERN AREAS.
DESPITE THE HIGH HEIGHTS THIS COMING WEEKEND AND THE WARM 850 HPA
TEMPERATURES THE GEFS IMPLIES THE POTENTIAL AT LEAST IN NORTHERN
PA FOR A WINTRY MIX SUNDAY. THE STRONG SURFACE RIDGE IS PRESENT
AGAIN BY SATURDAY AND SUNDAY. GEFS AND CMCEFS SHOW A SORT OF
CLASSIC COLD AIR DAMMING SCENARIO OVER THE WEEKEND.
SO DESPITE THE LARGER SCALE HEIGHT RISES AND WARMER TEMPERATURES
ALOFT BY THE WEEKEND. THE LOW-LEVEL COLD AIR COULD MAKE THE TWO
EXPECTED PRECIPITATION EVENTS A BIT MORE INTERESTING THAN +1 TO
+3C 850 HPA TEMPERATURES WOULD IMPLY. AT THIS TIME MOST OF THE
PRECIPITATION EVENTS...TUEDAYS...FRIDAY AND SUNDAY TIME-FRAME LOOK
A BIT MOISTURE STARVED.
&&
.AVIATION /12Z MONDAY THROUGH FRIDAY/...
UPWARD MOTION AHEAD OF NEXT UPSTREAM CLIPPER HELPING TO THICKEN
MID CLOUDS ACROSS THE REGION THIS MORNING.
WEAK LOW PRES SYSTEM TRACKING SOUTH OF PA WILL SPREAD LIGHT SNOW
AND DETERIORATING VSBYS ACROSS MAINLY SOUTHWEST PA STARTING THIS AFTN.
IFR CONDS APPEAR LIKELY AT JST...WHERE OROGRAPHIC LIFT WILL
ENHANCE THE SNOW...AND POSSIBLE AT AOO.
OUTLOOK...
TUE...EARLY FOG POSSIBLE. LGT SNOW/REDUCED VSBYS POSS LATE.
WED...NO SIG WX EXPECTED.
THU...SNOW POSSIBLE LATE...MAINLY NORTH.
FRI...SNOW POSSIBLE EARLY...MAINLY NORTH.
&&
.CTP WATCHES/WARNINGS/ADVISORIES...
LAKE EFFECT SNOW ADVISORY UNTIL 1 AM EST TUESDAY FOR PAZ004-
005.
WINTER WEATHER ADVISORY UNTIL 1 AM EST TUESDAY FOR PAZ024-033.
&&
$$
SYNOPSIS...GRUMM
NEAR TERM...GRUMM
SHORT TERM...GRUMM
LONG TERM...GRUMM/LAMBERT
AVIATION...FITZGERALD/GARTNER
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
648 AM EST MON FEB 4 2013
.SYNOPSIS...
A DEEP 500 HPA TROUGH OVER EASTERN NORTH AMERICA WILL SLOWLY
WEAKEN AND LIFT OUT AS THE WEEK PROGRESSES. AT LEAST TWO CLIPPER
LIKE WAVES WILL MOVE ACROSS OUR AREA MONDAY AND TUESDAY...AS THIS
HAPPENS. BY THE END OF THE WEEK THE TROUGH AND LOW-LEVEL COLD AIR WILL
BE REPLACED BY A RIDGE AND GENERALLY WARMER AIR. THIS IMPLIES A
GENERAL WARMING TREND AS THE WEEK PROGRESSES AS 850 HPA
TEMPERATURES SHOULD BE ABOUT 1 STANDARD DEVIATION ABOVE NORMAL BY
THE WEEKEND.
&&
.NEAR TERM /UNTIL 10 AM THIS MORNING/...
RADAR STILL SHOWS NARROW BANDS OF LIGHT SNOW OVER CENTRAL PA WHICH
DO NOT EXTEND MUCH BEYOND THE RIDGE VALLEY SYSTEM. NO REPORTS OF
ANY SIGNIFICANT SNOWS. BEST SNOW AREAS APPEAR JUST NORTH OF NY/PA
BORDER AND SW MTS WERE OBSERVATIONS AND RADAR SHOWED MORE
CONSISTENT SNOWS. SATELLITE IMAGERY SEEMS TO SHOW THE CLOUDS
COVERING MOSTLY WESTERN HALF TO ABOUT TWO THIRDS OF THE STATE. HAS
BEEN MOSTLY CLEAR IN SOME OF SOUTHEASTERN AREAS.
THE CIRRUS WITH THE APPROACHING CLIPPER HAS MOVED OVER MOST OF
OHIO AND SHOULD BE IN PA WITHIN HOURS. AFTERNOON SNOW IS GETTING CLOSER.
TEMPERATURES MAINLY IN THE TEENS AND TWENTIES ACROSS THE REGION
THIS MORNING WITH STEADY WEST WINDS. SHOULD SEE SLOW RISE IN TEMPS
THIS AM AND STEADILY INCREASING CLOUDS...THOUGH MOSTLY CLOUDY IN
WEST WITH ALL THE LOW CLOUDS.
&&
.SHORT TERM /10 AM THIS MORNING THROUGH 6 PM TUESDAY/...
THE CLOUDS FROM THE CLIPPER ARE CLEARLY ZIPPING ACROSS OHIO THIS
MORNING AND HEADED OUR WAY FAST. TIMING LOOKS GOOD AND CONSISTENT
WITH RAP AND 06Z NAM CLOSE TO PREVIOUS FORECASTS OF 03Z SREF.
EXPECT SNOW TO ARRIVE AN HOUR OF ABOUT 2 PM IN THE WEST.
ONLY RUB IS THE 06Z NAM IMPLIES THERE COULD BE SOME SPOTTY 0.4 TO
0.50 INCH QPF VALUES IN EXTREME SW PA. A FEW HIGHER ELEVATIONS
SITES WITH 16 TO 20:1 RATIOS COULD SEE OVER 6 INCHES OF SNOW.
THOUGH MOST LOCATIONS SHOULD BE IN THE MORE GENERAL 3-5 RANGE. SO
DID NOT PUT UP A WINTER STORM WARNING FOR WHAT MIGHT BE HEAVY SNOW
ON HIGHER RIDGES OF SOMERSET COUNTY. BUT THERE COULD BE SOME
ISOLATED AMOUNTS AROUND OR JUST OVER 6 INCHES.
PREVIOUS DISCUSSION STILL VALID:
THE LATEST HIGH RESOLUTION MODELS ALL IMPLY A BRIEF PERIOD OF PERHAPS
MODERATE SNOW IN THE SW AREAS NEAR THE MD BORDER. THE 03Z SREF TOO
SUPPORTS THIS CONCEPT WITH SNOW ARRIVING A FEW HOURS EITHER SIDE
OF ABOUT 2 PM IN WESTERN PA. THE SREF IMPLIES 0.1 TO 0.20 INCHES
OF QPF IN SW MOUNTAINS WHICH WOULD BE A GOOD 4-5 INCHES OF VERY
FLUFFY SNOW. THE SREF MEAN IMPLIES ISOLATED 0.30 AREAS FOR STORM
TOTALS IN SOMERSET COUNTY. THE AXIS OF HIGHEST POPS AND HIGHEST
QPFS RUN ALONG THE PA/MD BORDER AND SOUTH. THOUGH BEST QPF IN OUR
AREA ARE IN SW MTS.
INDICATIONS ARE MOST OF THE SYNOPTIC SNOWS WILL END QUICKLY
BETWEEN 10 PM AND 1 AM TONIGHT. SHOWED SNOW AMOUNTS RAPIDLY
LOWERING TO NORTH WITH EVENT AND SNOW:WATER RATIOS IN THE 16 TO
20:1 RANGE.
SREF IS NOT OPTIMISTIC WITH THE 3-5 INCHES IN NW AREAS BUT THIS
COULD BE A MODEL RESOLUTION ISSUE AND DID NOT MESS WITH THIS TOO
MUCH UNTIL WE SEE NEWER GUIDANCE.
STRONG WESTERLY WIND MAXIMUM MOVES OVER SOUTHERN TIER MONDAY
AFTERNOON SO WE COULD BRING DOWN GUSTS IN 15 TO 20 MPH RANGE.
THE WINTER WEATHER ADVISORY FOR THE LAURELS TO 06Z TUESDAY AND
ISSUED A LAKE EFFECT SNOW ADVISORY FOR THE NW MTNS FROM 00Z MONDAY
TO 06Z TUESDAY.
THE NEXT WAVE SHOULD NOT ARRIVE UNTIL TUESDAY AFTERNOON OR EVENING
WITH ANOTHER SHOT AT SOME ACCUMULATING SNOWS OF 1-2 INCHES IN
NORTHERN TIER OF MORE FLUFFY SNOWS.
&&
.LONG TERM /TUESDAY NIGHT THROUGH SUNDAY/...
THE SECOND CLIPPER WILL BRING SNOW (SEE ABOVE) TO THE REGION
MAINLY LATE TUESDAY AFTERNOON INTO TUESDAY NIGHT. BEST CHANCE OF
1-2 INCHES OF SNOW SHOULD BE ACROSS NORTHERN AREAS.
PREVIOUS DISCUSSION...THE LARGER SCALE PATTERN TUESDAY THROUGH
SUNDAY SHOWS THE TROUGH OVER THE EAST WEAKENING AND LIFTING OUT.
BY THE WEEKEND THE 500 HPA HEIGHTS SHOULD BE SLIGHTLY ABOVE NORMAL
AS WELL AS THE 850 HPA TEMPERATURES. NORTHERN STREAM SHORT-WAVES
COULD BRING PRECIPITATION TUESDAY INTO EARLY
WEDNESDAY...FRIDAY...AND SUNDAY INTO MONDAY. SOME HINTS ARE THAT
LOW- LEVEL COLD AIR COULD BE AN ISSUE WITH WINTRY MIX POSSIBLE IN
NORTHERN REGIONS SHOULD THIS HIGHLY UNCERTAIN WAVE ARRIVE AS
FORECAST LATER THIS WEEKEND.
TUESDAY AFTERNOON INTO EARLY WEDNESDAY SHOULD SEE YET ANOTHER CLIPPER
SYSTEM SPREAD SOME LIGHT SNOW INTO THE AREA DRAGGING SOME COLD AIR
INTO THE REGION. NOT NEARLY AS COLD AS THE PREVIOUS SURGES HAVE
BEEN.
THE QPF VALUES ARE VERY LIGHT...NOT SURPRISING AS THE MAIN
LOW IS CURRENTLY FORECAST TO PASS TO OUR NORTH...VIOLATING ONE OF
THE RULES OF CLIPPERS AND WHERE YOU WANT TO BE TO GET MORE SNOW.
THE SYSTEM DOES DRAG A STRONG SURFACE RIDGE INTO THE REGION WHICH
SUGGESTS THE LOW-LEVEL COLD AIR WILL BE SLOW TO RETREAT ON
THURSDAY AND FRIDAY.
ANOTHER NORTHERN STREAM IMPULSE POSSIBLE IN THE LATE THURSDAY-
FRIDAY TIME-FRAME WITH INDICATIONS OF A LIGHT SNOW EVENT OVER
NORTHERN TIER AREAS. THIS SYSTEM ERODES THE STRONG SURFACE RIDGE A
BIT FRIDAY INTO SATURDAY. THERE ARE HINTS OF POSSIBLE MIXED
PRECIPITATION ISSUES AS GEFS SHOWS POTENTIAL FOR LIGHT FREEZING
RAIN IN CENTRAL AREAS OVER THE RETREATING COLD AIR. MAINLY SNOW
NORTHERN AREAS.
DESPITE THE HIGH HEIGHTS THIS COMING WEEKEND AND THE WARM 850 HPA
TEMPERATURES THE GEFS IMPLIES THE POTENTIAL AT LEAST IN NORTHERN
PA FOR A WINTRY MIX SUNDAY. THE STRONG SURFACE RIDGE IS PRESENT
AGAIN BY SATURDAY AND SUNDAY. GEFS AND CMCEFS SHOW A SORT OF
CLASSIC COLD AIR DAMMING SCENARIO OVER THE WEEKEND.
SO DESPITE THE LARGER SCALE HEIGHT RISES AND WARMER TEMPERATURES
ALOFT BY THE WEEKEND. THE LOW-LEVEL COLD AIR COULD MAKE THE TWO
EXPECTED PRECIPITATION EVENTS A BIT MORE INTERESTING THAN +1 TO
+3C 850 HPA TEMPERATURES WOULD IMPLY. AT THIS TIME MOST OF THE
PRECIPITATION EVENTS...TUEDAYS...FRIDAY AND SUNDAY TIME-FRAME LOOK
A BIT MOISTURE STARVED.
&&
.AVIATION /12Z MONDAY THROUGH FRIDAY/...
COLD FRONT HAS PUSHED EAST OF CENTRAL PA LATE THIS EVENING. A
DRIER WESTERLY FLOW IN THE WAKE OF THE FRONT SHOULD ENSURE VFR
CONDS ACROSS THE SUSQ VALLEY FOR THE REST OF THE NIGHT. OVER THE W
MTNS...RESIDUAL LOW LVL MOISTURE ASCENDING THE HIGH TERRAIN
CONTINUES TO PRODUCE -SN/LOWER VSBYS AT JST AS OF 03Z.
HOWEVER...LOWERING INVERSION HGTS WILL LIKELY CAUSE -SN TO TAPER
OFF AFTER MIDNIGHT. HOWEVER...MDL DATA SUPPORTS A CONTINUATION OF
MVFR STRATOCU OVERNIGHT AT BFD AND JST. IN ADDITION...A TIGHT PRES
GRADIENT BEHIND COLD FRONT WILL RESULT IN A GUSTY WIND OVERNIGHT.
BUFKIT SOUNDING DATA SUPPORTS FREQUENT GUSTS TO ARND 20KTS
OVERNIGHT ACROSS THE W MTNS.
A WEAK LOW PRES SYSTEM TRACKING SOUTH OF PA WILL SPREAD LIGHT
SNOW AND DETERIORATING VSBYS ACROSS MAINLY SOUTHWEST PA MONDAY
AFTN. IFR CONDS APPEAR LIKELY AT JST...WHERE OROGRAPHIC LIFT WILL
ENHANCE THE SNOW...AND POSSIBLE AT AOO.
OUTLOOK...
TUE...EARLY FOG POSSIBLE. LGT SNOW/REDUCED VSBYS POSS LATE.
WED...NO SIG WX EXPECTED.
THU...SNOW POSSIBLE LATE...MAINLY NORTH.
FRI...SNOW POSSIBLE EARLY...MAINLY NORTH.
&&
.CTP WATCHES/WARNINGS/ADVISORIES...
LAKE EFFECT SNOW ADVISORY UNTIL 1 AM EST TUESDAY FOR PAZ004-
005.
WINTER WEATHER ADVISORY UNTIL 1 AM EST TUESDAY FOR PAZ024-033.
&&
$$
SYNOPSIS...GRUMM
NEAR TERM...GRUMM
SHORT TERM...GRUMM
LONG TERM...GRUMM/LAMBERT
AVIATION...FITZGERALD
AREA FORECAST DISCUSSION
NWS HOUSTON/GALVESTON TX
743 AM CST MON FEB 4 2013
.UPDATE...
LIGHT RAIN AND DRIZZLE BEING REPORTED IN THE HILL COUNTRY THIS
MORNING AND SHOULD SPREAD EAST SO HAVE NUDGED POPS BACK UP IN THE
NORTH THIS MORNING. LOW LEVELS WILL MOISTEN UP TODAY AND TONIGHT
AND THINK THAT SOME PATCHY FOG MAY DEVELOP TONIGHT OVER THE
SOUTHERN HALF OF THE AREA. WON`T ADD IT YET AND WILL LET THE
INCOMING SHIFT MAKE THE CALL. OTHERWISE THE FORECAST LOOKS ON
TRACK.
45
&&
.PREV DISCUSSION... /ISSUED 543 AM CST MON FEB 4 2013/
DISCUSSION...
SEE 12Z AVIATION DISCUSSION.
AVIATION...
A S/WV COUPLED WITH AN INCREASE IN MOISTURE SHOULD YIELD LOWER
CIGS THIS AFTN AND A SLIGHT CHANCE OF SHOWERS. LATEST RAP 13
GUIDANCE SUPPORTS LIGHT RAIN DEVELOPING IN A SMALL WINDOW BETWEEN
19-00Z. FCST SOUNDINGS SUPPORT THE RAP AND NAM 12 SOLUTIONS. CONFIDENCE
FOR TONIGHT IS LOW AS NUMERIC GUIDANCE SUPPORTS VLIFR CONDS.
MODELS CONTINUE TO HINT AT WIDESPREAD AREAS OF DENSE FOG AS WELL
BUT PREFER TO TAKE A MORE CONSERVATIVE APPROACH FOR NOW. 43
PREV DISCUSSION... /ISSUED 434 AM CST MON FEB 4 2013/
DISCUSSION...
WARM WITH ABUNDANT CLOUDY COVER TODAY AND A CHANCE OF RAIN AND
SHOWERS. S/W IN NORTHEAST NEW MEXICO WILL CONTINUE TO MOVE EAST-
SOUTHEAST AND SHOULD INCREASE THE RAIN CHANCES THIS AFTERNOON AND
EVENING. PICKING UP SOME LIGHT RETURNS OVER THE HILL COUNTRY BUT
DOESN`T LOOK LIKE IT IS MAKING IT TO THE GROUND YET. EXPECT RAINS
MAINLY ACROSS THE NORTHERN 3/4THS OF THE AREA THIS AFTERNOON AND
THEN SHIFTING EAST WITH THE PROGRESSION OF THE SHORTWAVE.
INSTABILITY IS PRESENT BUT IS LIMITED AND WITH THE WEAK CAP HAVE
LOWERED POPS JUST SLIGHTLY. LIGHT PRECIP AMOUNTS SHOULD BE THE
NORM FOR THOSE THAT SEE RAIN. COLD FRONT THOUGH ALMOST NO CAA WILL
MOVE DOWN TO THE I-10 AREA OR A LITTLE NORTH OF IT TUESDAY
AFTERNOON. THE BOUNDARY LIFTS BACK NORTH ON WEDNESDAY AS MORE
VIGOROUS SUBTROPICAL S/W APPROACHES AND WITH GREATER MOISTURE
PRESENT (PW INCREASE TO 1.5") EXPECT MORE WIDESPREAD RAINFALL AND
POSSIBLY SOME HEAVIER RAINS ACROSS THE SOUTHERN HALF OF THE
BOUNDARY. SYSTEM LOOKS TO BE BETTER IN PHASE FOR PRECIP HERE.
ENSEMBLE GFS THOUGH HAS A HUGE SPREAD ON RAINFALL CHANCES SO FOR
NOW WILL FAVOR THE OPERATIONAL GFS RUN AND KEEP THE POPS IN THE
40-50 PERCENT RANGE. SLOW MOVING ASSOCIATED LOW TRACKS INTO AND
THROUGH THE AREA BY LATE THURSDAY. AGAIN THE ASSOCIATED COLD FRONT
IS HARD TO CALL A COLD FRONT GIVEN THE VERY WEAK CAA. TEMPERATURES
THIS WEEK WILL BE AT OR ABOVE NORMAL PERHAPS BY AS MUCH AS 10
DEGREES. MAY HAVE ANOTHER WELL ORGANIZED S/W THAT COMES IN ON THE
SUBTROPICAL JET LATE SUNDAY OR MONDAY WITH ANOTHER DECENT SHOT OF
RAIN.
45
MARINE...
ONSHORE WINDS WILL PREVAIL THROUGH WEDNESDAY AS AN AREA OF LOW
PRESSURE OVER THE TEXAS PANHANDLE MEANDERS ACROSS NORTH TEXAS. A
WEAK FRONT WILL APPROACH SOUTHEAST TEXAS BUT STALL WELL NORTH OF THE
COASTAL WATERS. ONSHORE WINDS ARE EXPECTED TO PREVAIL THROUGH EARLY
THURSDAY. A WEAK FRONT WILL PUSH INTO THE COASTAL WATERS ON FRIDAY
WITH A BRIEF WIND SHIFT. ONSHORE WINDS WILL REDEVELOP AND STRENGTHEN
ON SATURDAY. ANOTHER FRONT IS EXPECTED NEXT MONDAY. TIDE LEVELS ARE
EXPECTED TO REMAIN WITHIN NORMAL VALUES.
43
&&
.PRELIMINARY POINT TEMPS/POPS...
COLLEGE STATION (CLL) 72 55 72 55 72 / 40 20 10 10 20
HOUSTON (IAH) 73 58 74 56 73 / 40 30 10 10 30
GALVESTON (GLS) 69 62 70 61 70 / 30 20 10 10 50
&&
.HGX WATCHES/WARNINGS/ADVISORIES...
TX...NONE.
GM...NONE.
&&
$$
DISCUSSION...45
AREA FORECAST DISCUSSION
NWS HOUSTON/GALVESTON TX
543 AM CST MON FEB 4 2013
.DISCUSSION...
SEE 12Z AVIATION DISCUSSION.
&&
.AVIATION...
A S/WV COUPLED WITH AN INCREASE IN MOISTURE SHOULD YIELD LOWER
CIGS THIS AFTN AND A SLIGHT CHANCE OF SHOWERS. LATEST RAP 13
GUIDANCE SUPPORTS LIGHT RAIN DEVELOPING IN A SMALL WINDOW BETWEEN
19-00Z. FCST SOUNDINGS SUPPORT THE RAP AND NAM 12 SOLUTIONS. CONFIDENCE
FOR TONIGHT IS LOW AS NUMERIC GUIDANCE SUPPORTS VLIFR CONDS.
MODELS CONTINUE TO HINT AT WIDESPREAD AREAS OF DENSE FOG AS WELL
BUT PREFER TO TAKE A MORE CONSERVATIVE APPROACH FOR NOW. 43
&&
.PREV DISCUSSION... /ISSUED 434 AM CST MON FEB 4 2013/
DISCUSSION...
WARM WITH ABUNDANT CLOUDY COVER TODAY AND A CHANCE OF RAIN AND
SHOWERS. S/W IN NORTHEAST NEW MEXICO WILL CONTINUE TO MOVE EAST-
SOUTHEAST AND SHOULD INCREASE THE RAIN CHANCES THIS AFTERNOON AND
EVENING. PICKING UP SOME LIGHT RETURNS OVER THE HILL COUNTRY BUT
DOESN`T LOOK LIKE IT IS MAKING IT TO THE GROUND YET. EXPECT RAINS
MAINLY ACROSS THE NORTHERN 3/4THS OF THE AREA THIS AFTERNOON AND
THEN SHIFTING EAST WITH THE PROGRESSION OF THE SHORTWAVE.
INSTABILITY IS PRESENT BUT IS LIMITED AND WITH THE WEAK CAP HAVE
LOWERED POPS JUST SLIGHTLY. LIGHT PRECIP AMOUNTS SHOULD BE THE
NORM FOR THOSE THAT SEE RAIN. COLD FRONT THOUGH ALMOST NO CAA WILL
MOVE DOWN TO THE I-10 AREA OR A LITTLE NORTH OF IT TUESDAY
AFTERNOON. THE BOUNDARY LIFTS BACK NORTH ON WEDNESDAY AS MORE
VIGOROUS SUBTROPICAL S/W APPROACHES AND WITH GREATER MOISTURE
PRESENT (PW INCREASE TO 1.5") EXPECT MORE WIDESPREAD RAINFALL AND
POSSIBLY SOME HEAVIER RAINS ACROSS THE SOUTHERN HALF OF THE
BOUNDARY. SYSTEM LOOKS TO BE BETTER IN PHASE FOR PRECIP HERE.
ENSEMBLE GFS THOUGH HAS A HUGE SPREAD ON RAINFALL CHANCES SO FOR
NOW WILL FAVOR THE OPERATIONAL GFS RUN AND KEEP THE POPS IN THE
40-50 PERCENT RANGE. SLOW MOVING ASSOCIATED LOW TRACKS INTO AND
THROUGH THE AREA BY LATE THURSDAY. AGAIN THE ASSOCIATED COLD FRONT
IS HARD TO CALL A COLD FRONT GIVEN THE VERY WEAK CAA. TEMPERATURES
THIS WEEK WILL BE AT OR ABOVE NORMAL PERHAPS BY AS MUCH AS 10
DEGREES. MAY HAVE ANOTHER WELL ORGANIZED S/W THAT COMES IN ON THE
SUBTROPICAL JET LATE SUNDAY OR MONDAY WITH ANOTHER DECENT SHOT OF
RAIN.
45
MARINE...
ONSHORE WINDS WILL PREVAIL THROUGH WEDNESDAY AS AN AREA OF LOW
PRESSURE OVER THE TEXAS PANHANDLE MEANDERS ACROSS NORTH TEXAS. A
WEAK FRONT WILL APPROACH SOUTHEAST TEXAS BUT STALL WELL NORTH OF THE
COASTAL WATERS. ONSHORE WINDS ARE EXPECTED TO PREVAIL THROUGH EARLY
THURSDAY. A WEAK FRONT WILL PUSH INTO THE COASTAL WATERS ON FRIDAY
WITH A BRIEF WIND SHIFT. ONSHORE WINDS WILL REDEVELOP AND STRENGTHEN
ON SATURDAY. ANOTHER FRONT IS EXPECTED NEXT MONDAY. TIDE LEVELS ARE
EXPECTED TO REMAIN WITHIN NORMAL VALUES.
43
&&
.PRELIMINARY POINT TEMPS/POPS...
COLLEGE STATION (CLL) 72 55 72 55 72 / 20 20 10 10 20
HOUSTON (IAH) 73 58 74 56 73 / 40 30 10 10 30
GALVESTON (GLS) 69 62 70 61 70 / 30 20 10 10 50
&&
.HGX WATCHES/WARNINGS/ADVISORIES...
TX...NONE.
GM...NONE.
&&
$$
DISCUSSION...45
AVIATION/MARINE...43
AREA FORECAST DISCUSSION
NWS DENVER/BOULDER CO
328 PM MST MON FEB 4 2013
.SHORT TERM...MODERATE NORTHWEST FLOW ALOFT TO CONTINUE OVER THE
AREA THROUGH TONIGHT. CROSS MOUNTAIN FLOW HAS INCREASED TO AROUND
40 KTS JUST ABOVE MOUNTAIN TOP...WITH SOME GUSTS TO 50 MPH
OBSERVED ATOP LOVELAND PASS. GUSTS IN THE 30S WERE COMMON ALONG
THE FOOTHILLS. WESTERLY WINDS HAVE ALSO PUSHED ACROSS THE URBAN
CORRIDER WITH NORTHWEST WINDS ALONG THE WYOMING AND NEBRASKA
PANHANDLES. LASTEST RAP CROSS SECTIONS SHOW CROSS MOUNTAIN FLOW
GRADUALLY DECREASING TO 30 KTS DURING THE EVENING...THUS WINDS
SHOULD GRADUALLY DECREASE AS A RESULT WITH DRAINAGE PATTERN
PREVAILING. WAVE CLOUD ALONG FOOTHILLS AND URBAN CORRIDOR
BEGINNING TO DISSIPATE. LATEST WRF SYNTHETIC SATELLITE IMAGERY
SUGGESTING A DECREASE IN THE WAVE CLOUD THROUGH THE EVENING. THUS
SKIES SHOULD GRADUALLY CLEAR. ON TUESDAY...FLOW ALOFT BECOMES A
BIT MORE WESTERLY AS A WEAK TROUGH MOVES ACROSS WYOMING. SOME
INCREASE IN HIGH LEVEL MOISTURE THROUGH THE DAY...WITH PERHAPS
SOME DEVELOPMENT OF A WAVE CLOUD ALONG FOOTHILLS. NAM CROSS
SECTIONS SHOW CROSS MOUNTAIN FLOW OF AROUND 35 KTS...COULD SEE
SOME GUSTS AROUND 40 MPH AGAIN ACROSS THE RIDGES AND HIGHER
FOOTHILLS. ACROSS PLAINS....LATEST MODELS SUGGEST A WEAK SURFACE
HIGH MOVING INTO THE AREA DURING THE AFTERNOON...WHICH COULD PUSH
EASTERLY SURFACE WINDS AS FAR WEST AS THE FOOTHILLS. NOT ALOT OF
COOLING ASSOCIATED WITH THIS HIGH...SO TEMPERATURES TO CLIMB INTO
THE 50S WITH PERHAPS A FEW 60S IN THE DENVER VICINITY.
.LONG TERM...MODELS HAVE ZONAL FLOW ALOFT FOR THE CWA TUESDAY
NIGHT...THEN WEST-SOUTHWESTERLY FLOW WEDNESDAY MORNING. A VERY
WEAK UPPER TROUGH IS PROGGED TO MOVE ACROSS THE FORECAST AREA
WEDNESDAY AFTERNOON AND EVENING. FOR WEDNESDAY NIGHT THROUGH
THURSDAY NIGHT...MODERATE ZONAL FLOW IS PROGGED. THE SYNOPTIC
SCALE ENERGY IS WEAK THROUGH THE PERIODS. THE BOUNDARY LAYER FLOW
WILL TEND TOWARDS DOWNSLOPING TUESDAY NIGHT AND WEDNESDAY. BY
WEDNESDAY AFTERNOON AND EVENING...THERE IS A BRIEF SHOT OF
UPSLOPE FOR THE PLAINS INTO THE FOOTHILLS. ON THURSDAY...NORMAL
DUIRNAL TRENDS ARE LIKELY. CONCERNING MOISTURE...THERE IS SOME IN
THE MID AND UPPER LEVELS TUESDAY NIGHT. THE NAM AND ECMWF HAVE
LIMITED MOISTURE ON WEDNESDAY AND WEDNESDAY EVENING WITH THE WEAK
UPPER TROUGH. HOWEVER...THE GFS HAS CONSIDERABLY MORE MOISTURE ON
WEDNESDAY AND WEDNESDAY EVENING. THURSDAY AND THURSDAY NIGHT LOOK
PRETTY DRY ON ALL THE MODELS. THE QPF FIELDS FROM THE GFS AND ECMWF
HAVE A TAD OF MEASURABLE SNOWFALL OVER THE SOUTHWESTERN PART OF
THE CWA WEDNESDAY AFTERNOON AND EVENING. FOR POPS...WILL KEEP A
TAD IN OVER THE HIGH MOUNTAINS WEDNESDAY AND WEDNESDAY EVENING.
FOR TEMPERATURES...WEDNESDAY`S HIGHS ARE 1-3 C COOLER THAN
TUESDAY`S. THURSDAY`S HIGHS ARE CLOSE TO WEDNESDAY`S. FOR THE
LATER DAYS...FRIDAY THROUGH MONDAY...MODELS SHOW INCREASING
SOUTHWESTERLY FLOW ALOFT ON FRIDAY. ON SATURDAY...MODELS HAVE A
CLOSED LOW OVER CENTRAL UTAH AROUND MID DAY. BY SUNDAY MORNING AT
12Z...MODELS ARE ALL OVER THE PLACE WITH THE SYSTEM. THE GFS HAS
THE CLOSED LOW CENTER OVER NORTHERN ARIZONA...THE ECMWF OVER THE
NORTHWESTERN CORNER OF KANSAS...THE CANADIAN OVER THE SOUTHEASTERN
CORNER OF COLORADO. AT 12Z MONDAY MORNING...THERE IS AN UPPER
TROUGH AXIS STRETCHED NORTHEAST TO SOUTHWEST ACROSS THE CWA WITH
THE GFS STILL SHOWING A WEAKENING CLOSED CIRCULATION OVER EAST
CENTRAL ARIZONA. OVERALL AGREEMENT IS QUITE POOR. THE COLD AIR IS
STILL INDICATED TO GET INTO THE CWA BY EARLY SATURDAY MORNING.
HOWEVER...THE TIMING WITH THE MOISTURE IS NEARLY 24 HOURS LATER
THAN YESTEDAY`S 12Z RUNS INDICATED. THE CANADIAN STILL LOOKS TO
GIVE THE PLAINS A DECENT SNOWFALL...THE REST NOT. OVERALL...IT IS
A CONVOLUTED MESS. HOPEFULLY AS TIME MOVES FORWARD...THE MODELS
IMPROVE CONCERNING CONSENSUS. WILL LEAVE POPS IN THE 20-40% RANGE
FOR NOW FROM SATURDAY AFTERNOON INTO SUNDAY EVENING.
&&
.AVIATION...WESTERLY WINDS HAVE PUSHED ACROSS BJC AND DIA WITH
SOME GUSTS TO 25 KTS. LIGHTER WINDS NOTED AT APA. WINDS TO
CONTINUE WESTERLY AT DEN AND BJC INTO THE EVENING HOURS BEFORE
DECREASING AND BECOMING SOUTHWEST BY 03Z. WINDS SHOULD REMAIN
LIGHT WESTERLY AT APA...THEN SOUTHERLY DURING THE EVENING. MID AND
HIGH LEVEL MOISTURE TO GRADUALLY DECREASE DURING THE EVENING AS
THE WAVE CLOUD CONTINUES TO DISSIPATE. ON TUESDAY...SOUTHERLY
WINDS TO PREVAIL BY 16Z...AND COULD SHIFT TO THE SOUTHEAST BY 20Z.
SPEEDS OF AROUND 8 KTS WILL PREVAIL.
&&
.BOU WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...D-L
LONG TERM....RJK
AVIATION...D-L
AREA FORECAST DISCUSSION
NWS DENVER/BOULDER CO
959 AM MST MON FEB 4 2013
.UPDATE...
&&
.SHORT TERM...CURRENT FORECASTS STILL LOOK REASONABLE. MODERATE
NORTHWEST FLOW ALOFT TO CONTINUE ACROSS COLORADO THROUGH TONIGHT.
LATEST RAP QG VERTICAL VELOCITY PROGS SHOW WEAK MID LEVEL DESCENT
ACROSS THE REGION...AIDING IN GUSTY WINDS ACROSS THE HIGHER RIDGES
AND ALONG FOOTHILLS. MODELS INDICATING CROSS MOUNTAIN FLOW OF
AROUND 30 KTS...SO GUSTS UP TO 50 MPH NOT OUT OF THE QUESTION IN
THE WIND PRONE AREAS. ACROSS PLAINS...SOUTHEAST GRADIENT WEAKENING
AND SHOULD BECOME NORTHWEST BY THE AFTERNOON. LATEST SYNTHETIC
SATELLITE IMAGERY SUGGESTING A BIT MORE CLOUD COVER ALONG THE
FRONT RANGE THROUGH THE DAY. MAY NEED TO INCREASE CLOUD COVER A
BIT. DON`T THINK THE CLOUDS WILL AFFECT THE EXPECTED TEMPERATURES.
&&
.AVIATION...SOUTHEAST GRADIENT STILL IN PLACE ACROSS THE AREA...
SHOWING SIGNS OF WEAKENING. TREND FOR THE WINDS TO BECOME
SOUTHWEST THEN NORTHWEST STILL ON TRACK THOUGH TIMING TO BE
DELAYED A FEW HOURS. SPEEDS SEEM REASONABLE AT THIS TIME. THERE
MAY ALSO BE A BIT MORE WAVE CLOUD ALONG THE FOOTHILLS...THOUGH
CEILINGS SHOULD REMAIN ABOVE 12000 FEET.
&&
.PREV DISCUSSION... /ISSUED 336 AM MST MON FEB 4 2013/
SHORT TERM...NORTHERN COLORADO WILL BE UNDER A MODERATE NORTHWEST
FLOW PATTERN TODAY AND TONIGHT BEHIND LAST EVENINGS WEAK UPPER
WAVE. THERE IS SOME MID AND HIGH LEVEL MOISTURE OVER THE NORTHERN
ROCKIES WHICH WILL MOVE INTO COLORADO DURING THE DAY IN THE FLOW.
THE WRF SIMULATED SATELLITE IMAGERY SHOWING SOME WAVE CLOUDS OVER
THE FRONT RANGE BUT NOT THAT EXTENSIVE AND WOULD APPEAR A PARTLY
CLOUDY FORECAST SHOULD HANDLE THE AFTERNOON CONDITIONS. THE LOWER
LEVELS OF THE ATMOSPHERE WILL REMAIN DRY SO NO PRECIP OVER NEXT 24
HOURS. GIVEN THE STRENGTH OF FLOW...EXPECT SOME GUSTY WINDS OVER
THE HIGHER MOUNTAINS AND EAST SLOPES. CROSS SECTIONS SHOWING CROSS
BARRIER FLOW OF AROUND 30KT... ESPECIALLY THIS AFTERNOON AND
TONIGHT WHICH WILL RESULT IN SOME GUSTS UP TO 40-50 MPH IN WIND
PRONE AREAS.
LONG TERM...WLY FLOW ALOFT WILL BE OVER NRN CO ON TUE WITH ONLY
SOME HIGHER LEVEL MOISTURE EMBEDDED IN THE FLOW SO WILL KEEP FCST
DRY. HIGHS SHOULD RISE INTO THE 50S ON TUE ACROSS NERN CO WITH
NEAR 60 POSSIBLE AROUND DENVER. BY WED A WK UPPER LEVEL TROUGH
WILL QUICKLY MOVE ACROSS THE AREA WITH SOME INCREASE IN MID LVL
MOISTURE WHICH MAY BRING A SLIGHT CHC OF SNOW IN THE MTNS. A CDFNT
WILL MOVE ACROSS NERN CO FM MID AFTN INTO THE EVENING HOURS. WILL
KEEP HIGHS MAINLY IN THE LOWER TO 50S OVER THE PLAINS. LATEST
ECMWF AND GFS SHOWS SOME LIGHT PCPN IN THE SRN FOOTHILLS WED
EVENING WHERE UPSLOPE FLOW IS ENHANCED SO MAY NEED SOME LOW POPS N
THIS AREA.
BY THU THE FLOW ALOFT WILL BE WLY WITH A DRY AIRMASS IN PLACE SO
WILL NOT MENTION ANY PCPN. 850-700 MB TEMPS ARE A FEW DEGREES
LOWER SO WILL KEEP HIGHS IN THE UPPER 40S TO LOWER 50S ACROSS NERN
CO. FOR FRI THE FLOW ALOFT WILL BECOME MORE SWLY AS AN UPPER LEVEL
STORM SYSTEM DEVELOPS OVER THE WRN US. AT THIS TIME IT LOOKS LIKE
ONLY SOME HIGHER LEVEL MOISTURE WILL AFFECT THE AREA SO WILL NOT
MENTION ANY PCPN IN THE MTNS THRU THE AFTN HOURS. HIGHS SHOULD BE
IN THE LOWER TO MID 50S ACROSS NERN CO BASED ON CURRENT 850-700 MB
TEMPS.
FOR THE WEEKEND ONCE AGAIN THERE IS A LOT OF UNCERTAINTY ON WHERE
THE UPPER LEVEL LOW OVER THE WRN US WILL MOVE AND HOW FAST. THE
LATST GFS HAS A SPLITTING SYTEM WITH ONE PIECE OF ENERGY TRACKING
ACROSS NERN CO BY SAT NIGHT WHILE THE 2ND PIECE OF ENERGY
EVENTUALLY DROPS SOUTHWARD INTO ARIZONA BY SUN. IF THIS HAPPENS
THE BEST CHC OF PCPN WOULD PROBABLY BE SAT NIGHT WITH LIMITED
SNOWFALL. MEANWHILE THE ECMWF AND GEM HAVE A MORE CONSOLIDATED
SYSTEM NEAR THE FOUR CORNERS SAT NIGHT WHICH MOVES ACROSS SRN
COLORADO INTO SWRN KANSAS BY SUN AFTN. NATURALLY IF THIS WERE TO
HAPPEN THEN NRN CO WOULD BE UNDER THE GUN FOR A SIGNIFICANT WINTER
STORM. THE LONGER RANGE MODELS HAVE BEEN ALL OVER THE PLACE THE
LAST 3 NIGHTS WITH THIS SYSTEM AND WITH IT STILL WAY OUT OVER
THE PACIFIC OCEAN CONFIDENCE IS NOT VERY HIGH AS TO WHAT MAY
EVENTUALLY TRANSPIRE. AT THIS POINT THE BEST WAY TO GO IS TO KEEP
A CHC OF SNOW IN THE MTNS SAT THRU SUN WITH A SLIGHT CHC ELSEWHERE
UNTIL IT BECOMES MORE CLEAR HOW THINGS ARE GOING TO EVOLVE.
AVIATION...VFR CONDITIONS THROUGH TONIGHT WITH SOME WAVE
CLOUDINESS THROUGH THE PERIOD...ESPECIALLY THIS AFTERNOON AND
EVENING. SURFACE WINDS AGAIN STARTING FROM THE SOUTH AND SOUTHWEST
AND APPEARS ENOUGH WEST TO EAST SURFACE GRADIENT AND LOW LEVEL
MIXING FOR WINDS SHIFTING WEST AND NORTHWEST THIS AFTERNOON. WINDS
WOULD BE STRONGEST AT BJC.
&&
.BOU WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...D-L
LONG TERM....RPK
AVIATION...D-L
AREA FORECAST DISCUSSION
NWS LINCOLN IL
311 PM CST MON FEB 4 2013
.DISCUSSION...
ISSUED 300 PM CST MON FEB 4 2013
THE ISSUES THIS FORECAST WILL BE A TUESDAY CLIPPER...A COLD FRONT
THURSDAY...A WARMING TREND FOR THE WEEKEND...THEN A SPRING-LIKE
STORM SYSTEM LIFTING THROUGH NW IL LATER ON SUNDAY AND SUNDAY
NIGHT. NO MAJOR MODEL DIFFERENCES THROUGH THE WEEK...EVEN THROUGH
THE SUNDAY SYSTEM. WILL USE A BLEND AND KEEP RELATIVE CONSISTENCY
WITH THIS UPDATE.
SHORT TERM...TONIGHT THROUGH WEDNESDAY.
THE CLEARING ACROSS CENTRAL IL APPEARS TO BE SHORT LIVED AS
SATELLITE IMAGES SHOW A BAND OF LOW STRATO-CU ADVANCING EAST OF
THE IL RIVER AS OF 230PM. WE CAN SEE THE GROUND THROUGH THE
CLOUDS...INDICATING THE MOISTURE LAYER IS RATHER THIN...BUT
A SUBSIDENCE INVERSION ASSOCIATED ADVANCING HIGH PRESSURE MAY BE
ENOUGH TO TRAP THAT MOISTURE TONIGHT ALLOWING FOR STRATUS
REDEVELOPMENT. WILL KEEP TONIGHT/S SKY FORECAST ON THE PESSIMISTIC
SIDE.
THE NEXT CLIPPER SYSTEM WILL PASS NORTH OF IL ON TUESDAY...WITH
THE PRIMARY INFLUENCE FOR ANY OF OUR COUNTIES BEING FLURRIES
ACROSS THE NORTH FROM GALESBURG TO CHAMPAIGN. NO ACCUMULATION WILL
REACH THIS FAR SOUTH AS THE PRIMARY ISENTROPIC LIFT AND MOISTURE
CONVERGENCE WILL BE IN N IL AND WIS. WE WILL SEE GUSTY W-SW WINDS
DEVELOP TOWARD MID-DAY AHEAD OF THE SURFACE TROUGH...MAKING HIGHS
IN THE MID 30S TO LOW 40S FEEL A LITTLE COLDER.
LITTLE CHANGE IN AIRMASS IS EXPECTED FOR TUE NIGHT AND WED AS
ZONAL FLOW BEGINS TO DEVELOP ALOFT. RISING HEIGHTS ALOFT ACROSS
THE EASTERN PLAINS WILL ALSO WORK TO SET THE STAGE FOR A GENERAL
WARMING TREND FOR LATE WEEK AND THE WEEKEND. DRY CONDITIONS WILL
BE SEEN TUES NIGHT THROUGH WED NIGHT UNDER RELATIVELY WEAK HIGH
PRESSURE.
LONG TERM...THURSDAY THROUGH MONDAY.
A LOW PRESSURE SYSTEM WILL TRACK FROM THE NORTHERN PLAINS AND INTO
THE WESTERN GREAT LAKES ON THURSDAY...DRAGGING A WEAKENING COLD
FRONT ACROSS ILLINOIS. A SOUTHERN STREAM LOW PRESSURE EXTENSION OF
THAT FRONT WILL BECOME THE DOMINANT FEATURE AS THE COLD FRONT
PASSES...POSSIBLY DIMINISHING OUR RAINFALL CHANCES LATE WED NIGHT
THROUGH THURS NIGHT.
HOWEVER...PRECIP TYPE MAY BE A CONCERN LATE WED NIGHT AND THURS
MORNING. FREEZING RAIN MAY PRODUCE SOME LIGHT ICING ACROSS OUR FAR
NORTH DURING THAT TIME. THE SURFACE MAY REMAIN JUST BELOW FREEZING
IN THE NORTH AS MID LEVELS UNDERGO SIGNIFICANT WARMING WITH
INCREASING MOISTURE. FORECAST SOUNDINGS SHOW THE WET BULB BELOW
FREEZING FOR THE LOWEST 100 MB...WHICH MAY BE ENOUGH TO KEEP THE
GROUND TEMPS BELOW FREEZING DESPITE WEAK WARM ADVECTION EVEN AT
THE SURFACE. ANY ICING WOULD BE VERY LIGHT...AND MAINLY NORTH OF A
LINE FROM GALESBURG TO CHILLICOTHE.
BEFORE THE PRECIP ARRIVES WED NIGHT...WE EXPECT STEADY OF SLOWLY
RISING TEMPS IN OUR WESTERN AREAS...BUT POSSIBLY SOME COOLING
STILL IN OUR EASTERN AREAS WHERE SKIES MAY REMAIN CLEAR LONGER
INTO THE NIGHT. AS PRECIP EXPANDS EASTWARD THURSDAY MORNING...OUR
NORTHEAST MAY SEE SOME OF THAT FREEZING RAIN...MAINLY NORTH OF
I-74. THE COMPLICATED FORECAST FOR SURFACE TEMPERATURE MAKES IT
DIFFICULT TO DISCERN HOW MUCH FREEZING RAIN WILL DEVELOP...IF
ANY...BUT WE WILL CONTINUE TO KEEP A MENTION FOR WED NIGHT AND
THURS MORNING ACROSS THE NORTH FOR NOW.
DRY CONDITIONS SHOULD RETURN FOR THURSDAY NIGHT THROUGH SATURDAY
AS HIGH PRESSURE PASSES ACROSS THE AREA.
SOUTHERLY FLOW AND WARMING WILL BECOME MORE PROMINENT ON SATURDAY
AS THE NEXT SYSTEM APPROACHES ACROSS THE PLAINS. RAIN IS EXPECTED
TO REACH OUR WESTERN COUNTIES ON SATURDAY NIGHT...BEFORE A SURFACE
LOW LIFTS NORTHEAST ACROSS FAR NW IL LATER ON SUNDAY. SHOWERS AND
THUNDERSTORMS ARE EXPECTED TO DEVELOP ON SUNDAY AS THE LOW PASSES
BY...AND THE COLD FRONT MOVES ACROSS ILLINOIS. SEVERE STORM
POTENTIAL LOOKS MARGINAL THIS FAR NORTH RIGHT NOW...BUT
INSTABILITY PARAMS DEFINITELY SUPPORT SOME THUNDERSTORMS. HIGHS ON
SUNDAY WILL BE THE WARMEST OF THE NEXT WEEK...WITH UPPER 40S TO
AROUND 50...AND SURFACE DEWPOINTS INTO THE 40S.
THE ARRIVAL OF COLDER AIR BEHIND THIS SYSTEM WILL MOST LIKELY NOT
ARRIVE UNTIL THE DRY AIR INTRUSION SHUTS DOWN THE PRECIP. SO WE DO
NOT EXPECT ANY SNOW IN OUR AREA BEHIND THIS LOW. IF THE TRACK OF
THE SURFACE LOW SHIFTS EAST...THAT MAY CHANGE. FOR NOW...WE EXPECT
ALL RAIN FROM THE SAT NIGHT-SUN NIGHT SYSTEM.
DRY CAN COOLER CONDITIONS ARE FORECAST FOR MONDAY WITH CLEARING
SKIES DURING THE AFTERNOON.
SHIMON
&&
.AVIATION...
ISSUED 1135 AM CST MON FEB 4 2013
1010 MB LOW PRESSURE OVER WEST CENTRAL IL HAS SW WINDS 10-15 KTS
AHEAD OF IT EAST OF THE IL RIVER AND WINDS TURN NNW BEHIND ITS
FRONT BY PIA/IL RIVER. LOW PRESSURE TO WEAKEN AS IT TRACKS ESE
THROUGH CENTRAL IL THIS AFTERNOON AND INTO THE CENTRAL OHIO VALLEY
BY SUNSET. SW WINDS EAST OF THE IL RIVER TO SHIFT NNW DURING THE
NEXT 1-3 HOURS...SHIFTING LAST AT CMI AND DEC. VFR CONDITIONS MUCH
OF THIS AFTERNOON OVER CENTRAL IL WITH SCATTERED-BROKEN MID/HIGH
CLOUDS. HRRR MODEL DEPICTS MVFR CLOUDS OVER IA AND NORTHERN IL
WELL AND USED THIS MODEL TO BRING THESE CLOUDS GRADUALLY SOUTHWARD
TO PIA AROUND 2030Z...BMI AROUND 22Z AND NEAR I-72 AROUND 00Z.
HRRR MODELS SHOWS THESE LOW CLOUDS LINGERING OVER CENTRAL IL
THIS EVENING. NAM LOW LEVEL RH FIELDS SHOWS THESE LOW CLOUDS
DECREASING FROM NW TO SE LATE TONIGHT AND TUE MORNING. A LIGHT FOG
WITH 4-6 MILES VSBYS POSSIBLE LATER TONIGHT INTO MID MORNING TUE.
WINDS BECOME LIGHT OVERNIGHT AND TURN BACK TO THE SW 10-15 KTS
DURING TUE MORNING. 1001 MB LOW PRESSURE OVER EAST-CENTRAL ALBERTA
TO DIVE SE INTO NW LOWER MI BY 18Z/NOON TUE KEEPING IT LIGHT SNOW
AND LOW CLOUDS MAINLY NORTH OF I-74 TUE.
07
&&
.ILX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
156 PM CST MON FEB 4 2013
.DISCUSSION...
1230 PM CST
HAVE OPTED TO EXTEND THE ADVISORY FOR LAKE AND COOK COUNTIES IN
NORTHEAST IL DUE TO LAKE INDUCED SNOW BAND MOVING TOWARD SHORE
EARLY THIS AFTERNOON.
THE MAIN SYNOPTIC EVENT THAT BROUGHT TWO TO FOUR INCHES OF SNOW
EARLIER THIS MORNING HAS EXITED...BUT WITH ITS DEPARTURE AND
NORTHEAST FLOW HAS DEVELOPED LAKE EFFECT SNOW. A PRONOUNCED BAND
FIRST SEEN ON VISIBLE SATELLITE NOW IS BECOMING BETTER DEFINED ON
THE TMKE RADAR. REFLECTIVITY HAS BEEN AS HIGH AS 30 DBZ AT TIMES
WITH THIS INDICATING LIKELY GOOD BURSTS OF SNOW. THE CONVERGENCE
SEEN ON SATELLITE AND RADAR LINES UP WELL WITH RAP AND NAM
DEPICTING IN THE LOWER LEVELS AND THE TREND HAS BEEN TO SLOW THIS
REORIENTING EASTWARD TOWARD NORTHWEST IN. THUS A FEW HOURS OF
SNOWFALL THIS AFTERNOON ARE FAVORED INTO EASTERN LAKE AND COOK
COUNTIES. EQUILIBRIUM LEVELS ARE SOMEWHAT LOW BEING AROUND
5000-6000 FT AND WIND SHEAR IN THE CLOUD DEPTH IS ALSO A LITTLE
HIGH /GREATER THAN 30 KT/...WHICH TOGETHER WILL LIKELY LIMIT
HEAVIER RATES FROM BEING WIDESPREAD OR TO MAKE IT FAR INLAND.
OTHER FACTORS SUCH AS THE CONVERGENCE...MOISTURE...AND INSTABILITY
ARE CONDUCIVE THOUGH FOR THE SNOW TO AT LEAST MAKE IT ONSHORE. SO
UNCERTAINTIES ON INTENSITY WOULD NORMALLY MEAN HOLDING OFF A
HEADLINE...HOWEVER THE WINTER WEATHER ADVISORY HAD BEEN ALLOWED TO
GO TO NOON ORIGINALLY FOR THE THREAT OF AT LEAST TEMPORARY
HEAVIER RATES AND BRINGING ADDITIONAL SNOWFALL TO WHAT HAS FALLEN.
WITH THE BAND/AREA OF SHOWERS OF SNOW MOVING INTO FAR NORTHEAST
ILLINOIS SHORTLY...SEE IT AS MORE PRUDENT TO CONTINUE ADVISORY.
MTF
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 20Z...
* NORTH WINDS BECOMING NORTH-NORTHWEST BY 22Z.
* LAKE-ENHANCED SNOW IN THE METROPOLITAN AREA WILL GET CLOSE TO
ORD AND MDW. AT THIS TIME APPEARS THE HEAVIER SNOW WITH LOWER
VISIBILITIES WILL STAY JUST EAST OF THE FIELDS.
PAW
//DISCUSSION...UPDATED 18Z...
LOW PRESSURE CENTER IN CENTRAL IL WILL MOVE EAST THIS AFTERNOON.
THIS WILL ALLOW WINDS TO SHIFT MORE TO THE NORTHEAST AND THEN
NORTH-NORTHWEST DURING THE AFTERNOON. THE EASTERLY WINDS FROM
THIS MORNING ARE SUPPORTING SOME BANDS OF LAKE-ENHANCED SNOW OVER
THE CHICAGO METROPOLITAN AREA AT MIDDAY. AS WINDS SHIFT AROUND
THESE AREAS WILL MOVE CLOSER TO THE LAKE AND THEN INTO NORTHWEST
INDIANA. AT THIS TIME IT APPEARS THAT ONLY GYY WOULD BE VULNERABLE
TO SEEING SOME OF THIS SNOW AND EVEN THERE CONFIDENCE IS LOW.
ANOTHER IN THE SERIES OF CLIPPER SYSTEMS WILL BE MOVING ACROSS THE
TERMINALS ON TUESDAY. THIS ONE WILL BE FURTHER NORTH AND SO THE
THE TERMINALS SHOULD BE ON THE FRINGE OF THE SNOW AREAS THIS TIME.
PAW
//ORD AND MDW CONFIDENCE...UPDATED 20Z...
* HIGH CONFIDENCE IN WIND TREND.
* MEDIUM CONFIDENCE IN LAKE-ENHANCED SNOW DETAILS.
PAW
//OUTLOOK FOR ORD/MDW FOR 00Z WEDNESDAY-12Z MONDAY...UPDATED 12Z...
TUESDAY NIGHT...VFR PSBL MVFR WITH LIGHT SNOW.
WEDNESDAY...VFR.
THURSDAY...PSBL MVFR WITH LIGHT RAIN/SNOW.
FRIDAY...VFR.
SATURDAY...VFR. PSBL MVFR WITH RAIN IN THE AFTN.
SUNDAY...MVFR. CHANCE OF RAIN.
BEACHLER
&&
.MARINE...
257 AM CST
ANOTHER AREA OF LOW PRESSURE WAS SLIDING EAST ACROSS IOWA INTO THE
OHIO VALLEY TODAY...WHICH WILL ALLOW A SLIGHT INCREASE IN THE WIND
GRADIENT FOR THE SOUTHERN HALF OF LAKE MICHIGAN. HIGH PRESSURE
WILL THEN QUICKLY BUILD IN FROM THE WEST AND PROVIDE RELATIVELY
QUIET WEATHER FOR LAKE MICHIGAN...BEFORE YET ANOTHER LOW PRESSURE
SLIDES INTO THE UPPER MIDWEST LATE TONIGHT/EARLY TUESDAY AND
ARRIVES ACROSS THE WESTERN GREAT LAKES TUESDAY AFTERNOON/EVENING.
THE GRADIENT DOES APPEAR TO INCREASE PRIOR AND JUST AFTER THIS
SYSTEM...THEN ANOTHER RIDGE OF HIGH PRESSURE IS FORECAST TO PUSH
INTO THE WESTERN GREAT LAKES REGION FOR WEDNESDAY. THIS RIDGE OF
HIGH PRESSURE WILL THEN SLIDE EAST TO THE EASTERN OHIO VALLEY
WEDNESDAY NIGHT...WITH AN INCREASING GRADIENT AND SOUTHERLY FLOW
FOR EARLY THURSDAY ACROSS LAKE MICHIGAN. THE GRADIENT THEN
INCREASES FURTHER ACROSS THE FAR NORTHERN PORTION OF THE LAKE
MIDDAY THURSDAY AS A WEAK LOW PRESSURE SLIDES OVER THE SOUTHERN
PORTION OF THE LAKE.
BEACHLER
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...WINTER WEATHER ADVISORY...ILZ006-ILZ014 UNTIL 4 PM MONDAY.
IN...WINTER WEATHER ADVISORY...INZ001-INZ002 UNTIL 6 PM MONDAY.
LM...NONE.
&&
$$
AREA FORECAST DISCUSSION...UPDATED
NWS CHICAGO/ROMEOVILLE IL
1231 PM CST MON FEB 4 2013
.DISCUSSION...
1230 PM CST
HAVE OPTED TO EXTEND THE ADVISORY FOR LAKE AND COOK COUNTIES IN
NORTHEAST IL DUE TO LAKE INDUCED SNOW BAND MOVING TOWARD SHORE
EARLY THIS AFTERNOON.
THE MAIN SYNOPTIC EVENT THAT BROUGHT TWO TO FOUR INCHES OF SNOW
EARLIER THIS MORNING HAS EXITED...BUT WITH ITS DEPARTURE AND
NORTHEAST FLOW HAS DEVELOPED LAKE EFFECT SNOW. A PRONOUNCED BAND
FIRST SEEN ON VISIBLE SATELLITE NOW IS BECOMING BETTER DEFINED ON
THE TMKE RADAR. REFLECTIVITY HAS BEEN AS HIGH AS 30 DBZ AT TIMES
WITH THIS INDICATING LIKELY GOOD BURSTS OF SNOW. THE CONVERGENCE
SEEN ON SATELLITE AND RADAR LINES UP WELL WITH RAP AND NAM
DEPICTING IN THE LOWER LEVELS AND THE TREND HAS BEEN TO SLOW THIS
REORIENTING EASTWARD TOWARD NORTHWEST IN. THUS A FEW HOURS OF
SNOWFALL THIS AFTERNOON ARE FAVORED INTO EASTERN LAKE AND COOK
COUNTIES. EQUILIBRIUM LEVELS ARE SOMEWHAT LOW BEING AROUND
5000-6000 FT AND WIND SHEAR IN THE CLOUD DEPTH IS ALSO A LITTLE
HIGH /GREATER THAN 30 KT/...WHICH TOGETHER WILL LIKELY LIMIT
HEAVIER RATES FROM BEING WIDESPREAD OR TO MAKE IT FAR INLAND.
OTHER FACTORS SUCH AS THE CONVERGENCE...MOISTURE...AND INSTABILITY
ARE CONDUCIVE THOUGH FOR THE SNOW TO AT LEAST MAKE IT ONSHORE. SO
UNCERTAINTIES ON INTENSITY WOULD NORMALLY MEAN HOLDING OFF A
HEADLINE...HOWEVER THE WINTER WEATHER ADVISORY HAD BEEN ALLOWED TO
GO TO NOON ORIGINALLY FOR THE THREAT OF AT LEAST TEMPORARY
HEAVIER RATES AND BRINGING ADDITIONAL SNOWFALL TO WHAT HAS FALLEN.
WITH THE BAND/AREA OF SHOWERS OF SNOW MOVING INTO FAR NORTHEAST
ILLINOIS SHORTLY...SEE IT AS MORE PRUDENT TO CONTINUE ADVISORY.
MTF
&&
//PREV DISCUSSION...
419 AM CST
MAIN CONCERN FOR THE NEXT FEW DAYS WILL BE THE CONTINUED PERIODIC
CHANCES FOR SNOW.
BEGINNING TO FEEL LIKE A BROKEN RECORD...REMEMBER RECORDS?...TALKING
ABOUT CLIPPERS BRINGING LIGHT SNOW TO NORTHERN ILLINOIS AND
NORTHWESTERN INDIANA...BUT THE MAIN CONCERN FOR THE REMAINDER OF THE
NIGHT AND INTO THE MORNING HOURS WILL BE THE ONGOING SNOW FALLING
OVER PORTIONS OF THE AREA. WHILE THE LOT RADAR IS STILL READING TOO
HIGH DUE TO MECHANICAL ISSUES...IT DOES INDICATE AN AREA OF SNOW
FALLING NORTH OF A LINE ROUGHLY FROM DIXON...TO JOLIET...TO
VALPARAISO. THIS SNOW IS ASSOCIATED WITH A MID LEVEL VORT MAX
TRACKING THROUGH THE AREA. WHILE LIGHT...TO OCCASIONALLY MODERATE
SNOW HAS BEEN FALLING SINCE EARLY LAST EVENING...THERE IS A VERY
SHARP CUTOFF TO THE SNOW WITH LITTLE OR NO SNOW FALLING SOUTH OF THE
AFOREMENTIONED LINE. EXPECT THIS TREND TO CONTINUE ACROSS THE AREA
THROUGH THE REMAINDER OF THE NIGHT AND INTO THE MORNING HOURS...BUT
AS THE MID LEVEL IMPULSE AND THE ASSOCIATED WEAK SFC LOW BEGIN TO
MOVE EAST OF THE AREA...SOME LIGHT SNOW SHOULD BEGIN TO SPREAD
SOUTHWARD...PERHAPS JUST SOUTH OF THE ILLINOIS AND KANKAKEE RIVERS.
HAVE RECEIVED ONLY A FEW SNOWFALL REPORTS THIS MORNING...BUT WHAT
OBSERVATIONS HAVE BEEN RECEIVED INDICATE THAT 2 TO 3 INCHES HAVE
FALLEN OVER NORTH-CENTRAL ILLINOIS...WHERE THE SNOW HAS BEEN FALLING
THE LONGEST...WITH LESSER AMOUNTS TO THE EAST. WITH ACCUMULATING
SNOW EXPECTED TO CONTINUE OVER MUCH OF THE AREA UNTIL UNTIL LATE
MORNING BEFORE TAPERING OFF TO FLURRIES BY EARLY AFTERNOON...THE
MORNING RUSH HOURS FOR TRAVELERS WILL BE HAZARDOUS...ESPECIALLY ON
UNTREATED OR UNPLOWED ROADS. WHEN ALL IS SAID AND DONE FOR THE
SYNOPTIC SNOW...GENERALLY EXPECT TOTALS OF 2 TO 4 INCHES NORTH OF
THE DIXON...TO JOLIET...TO VALPARAISO LINE AND LESSER AMOUNTS TO THE
SOUTH.
BY THIS AFTERNOON...THE FOCUS WILL SHIFT TO LAKE EFFECT SNOW
POTENTIAL FOR NORTHWESTERN INDIANA. SOME OF THE HIGH RESOLUTION
MODEL GUIDANCE INDICATES THE POTENTIAL FOR A MESO-VORTEX TO FORM
OVER THE SOUTHERN LAKE MICHIGAN WITH A CONVERGENCE ZONE EXTENDING
NORTHWARD. HAVE GENERALLY FOLLOWED THIS IDEA AND BACKED OFF ON THE
LAKE EFFECT SNOW POTENTIAL FOR FAR NERN ILLINOIS AND CONCENTRATED
THE LAKE EFFECT SNOW FORECAST OVER NWRN INDIANA...SINCE THE
MESO-VORTEX WOULD SHIFT WINDS INVOF THE ILLINOIS SHORE OF LAKE
MICHIGAN TO AN OFF-SHORE DIRECTION. GIVEN THE HIGHLY LOCALIZED
NATURE OF LAKE EFFECT SNOW ASSOCIATED WITH THESE TYPES OF
FEATURES...HAVE SOMEWHAT BROAD BRUSHED THE LAKE EFFECT
POTENTIAL...WITH THE POTENTIAL FOR A COUPLE INCHES OF LAKE EFFECT
SNOW AND LOCALLY HIGHER AMOUNTS POSSIBLE.
THE UPPER LEVEL PATTERN IS FINALLY SHOWING INDICATIONS OF DECREASING
AMPLITUDE AS PACIFIC SHORT WAVE ENERGY BEGINS TO BREAK DOWN THE WEST
COAST RIDGE. ALSO...THE EAST COAST TROUGH IS BROADENING AND
FLATTENING. HOWEVER...THE LOCAL AREA IS STILL UNDER FAST NWLY FLOW
ALOFT AND THE NEXT IS THE SERIES OF CLIPPERS IS EXPECTED TO IMPACT
THE REGION ON TUESDAY. THIS SYSTEM IS STILL BEING ADVERTISED TO BE
A BIT LESS FOCUSED AND SHOULD TAKE A MORE NORTHERLY TRACK ACROSS
THE MIDWEST AND GREAT LAKES REGIONS. SO...STILL EXPECT THE HEAVIEST
SNOWFALL AMOUNTS TO BE WELL NORTH OF THE WISCONSIN BORDER. AS FOR
TIMING...EXPECT THE INITIAL SNOW TO MOVE INTO THE FAR NORTHERN
PORTIONS OF THE CWA EARLY TUESDAY MORNING AND THEN SPREAD SOUTH AND
EAST. AGAIN...IT LOOKS LIKE THE FAR SOUTHERN COUNTIES OF THE CWA
WILL SEE LITTLE OR NO SNOW WHILE THE FAR NORTHERN COUNTIES MAY SEE 1
TO 2 INCHES BEFORE COMING TO AN END IN THE LATE AFTERNOON HOURS.
FOR THE LONGER TERM...FROM WEDNESDAY THROUGH NEXT WEEKEND...THE
LONGER RANGE MODEL GUIDANCE IS STILL IN VERY GOOD AGREEMENT ON
BREAKING DOWN THE UPPER LEVEL LONG WAVE PATTERN AND BECOMING MORE
PROGRESSIVE. THIS WILL ALLOW FOR TEMPERATURES TO MODERATE WITH
HIGHS IN THE UPPER 30S TO MIDDLE 40S...WITH SOME UPPER 40S POSSIBLE
OVER THE SOUTHERN PORTIONS OF THE CWA. ALSO...AS THE UPPER LEVEL
PATTERN FLATTENS...MORE PACIFIC SHORT WAVE ENERGY WILL BE ABLE TO
IMPACT THE AREA...BRINGING PERIODIC CHANCES FOR RAIN AS WELL AS SOME
SNOW...BUT WITH THE WARMING TREND...ANY SNOW SHOULD BE ON THE
WET...SLUSHY SIDE.
KREIN
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 18Z...
* WINDS GRADUALLY SHIFTING FROM EAST TO NORTHEAST AND THEN NORTH-
NORTHWEST THIS AFTERNOON. SPEEDS UP TO 12-14 KT.
* AREAS OF LAKE-ENHANCED SNOW IN THE CHICAGO METROPOLITAN AREA
EXPECTED TO REMAIN EAST OF ORD AND MDW.
PAW
//DISCUSSION...UPDATED 18Z...
LOW PRESSURE CENTER IN CENTRAL IL WILL MOVE EAST THIS AFTERNOON.
THIS WILL ALLOW WINDS TO SHIFT MORE TO THE NORTHEAST AND THEN
NORTH-NORTHWEST DURING THE AFTERNOON. THE EASTERLY WINDS FROM
THIS MORNING ARE SUPPORTING SOME BANDS OF LAKE-ENHANCED SNOW OVER
THE CHICAGO METROPOLITAN AREA AT MIDDAY. AS WINDS SHIFT AROUND
THESE AREAS WILL MOVE CLOSER TO THE LAKE AND THEN INTO NORTHWEST
INDIANA. AT THIS TIME IT APPEARS THAT ONLY GYY WOULD BE VULNERABLE
TO SEEING SOME OF THIS SNOW AND EVEN THERE CONFIDENCE IS LOW.
ANOTHER IN THE SERIES OF CLIPPER SYSTEMS WILL BE MOVING ACROSS THE
TERMINALS ON TUESDAY. THIS ONE WILL BE FURTHER NORTH AND SO THE
THE TERMINALS SHOULD BE ON THE FRINGE OF THE SNOW AREAS THIS TIME.
PAW
//ORD AND MDW CONFIDENCE...UPDATED 18Z...
* HIGH CONFIDENCE IN WIND TREND. MEDIUM CONFIDENCE IN TIMING.
* MEDIUM CONFIDENCE IN SNOW AREAS REMAINING EAST OF ORD AND MDW.
PAW
//OUTLOOK FOR ORD/MDW FOR 00Z WEDNESDAY-12Z MONDAY...UPDATED 12Z...
TUESDAY NIGHT...VFR PSBL MVFR WITH LIGHT SNOW.
WEDNESDAY...VFR.
THURSDAY...PSBL MVFR WITH LIGHT RAIN/SNOW.
FRIDAY...VFR.
SATURDAY...VFR. PSBL MVFR WITH RAIN IN THE AFTN.
SUNDAY...MVFR. CHANCE OF RAIN.
BEACHLER
&&
.MARINE...
257 AM CST
ANOTHER AREA OF LOW PRESSURE WAS SLIDING EAST ACROSS IOWA INTO THE
OHIO VALLEY TODAY...WHICH WILL ALLOW A SLIGHT INCREASE IN THE WIND
GRADIENT FOR THE SOUTHERN HALF OF LAKE MICHIGAN. HIGH PRESSURE
WILL THEN QUICKLY BUILD IN FROM THE WEST AND PROVIDE RELATIVELY
QUIET WEATHER FOR LAKE MICHIGAN...BEFORE YET ANOTHER LOW PRESSURE
SLIDES INTO THE UPPER MIDWEST LATE TONIGHT/EARLY TUESDAY AND
ARRIVES ACROSS THE WESTERN GREAT LAKES TUESDAY AFTERNOON/EVENING.
THE GRADIENT DOES APPEAR TO INCREASE PRIOR AND JUST AFTER THIS
SYSTEM...THEN ANOTHER RIDGE OF HIGH PRESSURE IS FORECAST TO PUSH
INTO THE WESTERN GREAT LAKES REGION FOR WEDNESDAY. THIS RIDGE OF
HIGH PRESSURE WILL THEN SLIDE EAST TO THE EASTERN OHIO VALLEY
WEDNESDAY NIGHT...WITH AN INCREASING GRADIENT AND SOUTHERLY FLOW
FOR EARLY THURSDAY ACROSS LAKE MICHIGAN. THE GRADIENT THEN
INCREASES FURTHER ACROSS THE FAR NORTHERN PORTION OF THE LAKE
MIDDAY THURSDAY AS A WEAK LOW PRESSURE SLIDES OVER THE SOUTHERN
PORTION OF THE LAKE.
BEACHLER
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...WINTER WEATHER ADVISORY...ILZ006-ILZ014 UNTIL 4 PM MONDAY.
IN...WINTER WEATHER ADVISORY...INZ001-INZ002 UNTIL 6 PM MONDAY.
LM...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS LINCOLN IL
1138 AM CST MON FEB 4 2013
.DISCUSSION...
ISSUED 1045 AM CST MON FEB 4 2013
UPDATING THE FORECAST TO INCREASE HIGH TEMPERATURES A FEW MORE
DEGREES. A FEW CITIES HAVE ALREADY REACH CURRENT HIGH TEMPS OR
EVEN A DEGREE OR TWO ABOVE LIKE GALESBURG AND PEORIA. HIGHS TO
RANGE FROM THE MID 30S NW OF THE IL RIVER...TO 40-45F OVER SW
AREAS AND NEAR 40F IN SE IL. CONTINUED SLIGHT CHANCE OF LIGHT
RAIN/SNOW IN EASTERN IL ESPECIALLY THIS AFTERNOON. 1010 LOW
PRESSURE OVER WEST CENTRAL IL TO WEAKEN AS IT TRACKS ESE ACROSS
CENTRAL IL AND INTO THE CENTRAL OHIO VALLEY BY SUNSET. WINDS WILL
SHIFT AROUND TO THE NNW BEHIND THIS SYSTEM DURING THE COURSE OF
THE AFTERNOON BRINGING IN COOLER AIR.
07
&&
.AVIATION...
ISSUED 1135 AM CST MON FEB 4 2013
1010 MB LOW PRESSURE OVER WEST CENTRAL IL HAS SW WINDS 10-15 KTS
AHEAD OF IT EAST OF THE IL RIVER AND WINDS TURN NNW BEHIND ITS
FRONT BY PIA/IL RIVER. LOW PRESSURE TO WEAKEN AS IT TRACKS ESE
THROUGH CENTRAL IL THIS AFTERNOON AND INTO THE CENTRAL OHIO VALLEY
BY SUNSET. SW WINDS EAST OF THE IL RIVER TO SHIFT NNW DURING THE
NEXT 1-3 HOURS...SHIFTING LAST AT CMI AND DEC. VFR CONDITIONS MUCH
OF THIS AFTERNOON OVER CENTRAL IL WITH SCATTERED-BROKEN MID/HIGH
CLOUDS. HRRR MODEL DEPICTS MVFR CLOUDS OVER IA AND NORTHERN IL
WELL AND USED THIS MODEL TO BRING THESE CLOUDS GRADUALLY SOUTHWARD
TO PIA AROUND 2030Z...BMI AROUND 22Z AND NEAR I-72 AROUND 00Z.
HRRR MODELS SHOWS THESE LOW CLOUDS LINGERING OVER CENTRAL IL
THIS EVENING. NAM LOW LEVEL RH FIELDS SHOWS THESE LOW CLOUDS
DECREASING FROM NW TO SE LATE TONIGHT AND TUE MORNING. A LIGHT FOG
WITH 4-6 MILES VSBYS POSSIBLE LATER TONIGHT INTO MID MORNING TUE.
WINDS BECOME LIGHT OVERNIGHT AND TURN BACK TO THE SW 10-15 KTS
DURING TUE MORNING. 1001 MB LOW PRESSURE OVER EASTCENTRAL ALBERTA
TO DIVE SE INTO NW LOWER MI BY 18Z/NOON TUE KEEPING IT LIGHT SNOW
AND LOW CLOUDS MAINLY NORTH OF I-74 TUE.
07
&&
.PREV DISCUSSION...
ISSUED 306 AM CST MON FEB 4 2013
WEAK HIGH PRESSURE SLIDING EAST AS ANOTHER WAVE OF PRECIP MOVES
ACROSS NRN IL THIS MORNING. NOT QUITE OUT OF THE INFLUENCE OF THE
PATTERN JUST YET...THE FIRST COUPLE OF ISSUES FOR THE FORECAST ARE
THE NEXT CLIPPER SYSTEMS MOVING THROUGH THE MIDWEST UNTIL THE END
OF THE WEEK. CONSIDERING THE PATTERN...THE AGREEMENT BTWN THE
MODELS IS IMPRESSIVE. NOT A LOT OF CHANGE IN THE FORECAST OVERALL
AS SOME RUN TO RUN CONSISTENCY IN THE MED AND LONGER RANGE. SOME
MINOR ISSUES IN THE SHORT TERM WITH PRECIP TODAY. ANOTHER ISSUE
FOR AS A RESULT OF THE SERIES OF WAVES MOVING THROUGH...NON
DIURNAL TEMPS FOR A COUPLE OF PERIODS. OVERALL...FORECAST
REMAINING RATHER CONSISTENT.
SHORT TERM...TODAY AND TOMORROW...
SNOW AND ASSOCIATED SHORT WAVE TO THE NORTH THIS MORNING WAS
PREVIOUSLY SET TO COLLIDE WITH ANOTHER WAVE TO THE SOUTH MIDDAY.
HOWEVER...WAVE TO THE NORTH A LITTLE AHEAD OF SCHEDULE...WITH SFC
WAVE TO THE SOUTHWEST LAGGING A BIT BEHIND. HAVE PULLED POPS DOWN
A BIT TO REFLECT THE DROP IN PROBABILITY...KEEPING SLIGHTS IN THIS
MORNING FOR EASTERN HALF OF CWA. BUT THIS AFTERNOON MAY SEE A
BETTER CHANCE WITH THE SOUTHERN WAVE IN THE SE. NAM/ECMWF/GFS
TRENDING A LITTLE DRIER...AND THE RUC IS COMPLETELY DRY THIS
AFTERNOON UNTIL THE WAVE PULLS OUT LATER THIS AFTERNOON. TEMPS A
BIT WARMER TODAY AS WELL WITH A SOUTHERLY COMPONENT RETURNING TO
THE SFC FLOW...ALBEIT WEAK. TOMORROWS WAVE PASSING JUST TO THE
NORTH AND CHANCES FOR PRECIP CONFINED WELL TO THE NORTH
AGAIN...WITH SIMILAR TEMPS TOMORROW AS TODAY...WITH BREEZY
WESTERLY WINDS KEEPING SOME WARM AIR MOVING INTO THE CWA.
LONG TERM...WEDNESDAY THROUGH SUNDAY...
WEDNESDAY DRY AND WARM AGAIN AHEAD OF THE NEXT SYSTEM FOR WED
NIGHT INTO THURSDAY. THOUGH THREAT FROM THE WEST WILL INCREASE FOR
THE OVERNIGHT HOURS ON WED NIGHT...THE BEST CHANCES WILL COME WITH
THE PASSAGE OF THE SFC BOUNDARY ON THUR/THU NIGHT. LAST MODEL RUN
DIVERGES SOMEWHAT WITH THE SOLUTIONS FOR THIS PARTICULAR WAVE. A
TROF DEEPENS OVER THE WEST COAST...AND THIS PARTICULAR SYSTEM IS
A SMALL PIECE OF THE ENERGY EJECTING OUT AHEAD OF THE MAIN TROF.
THE ECMWF IS FAR MORE AMPLIFIED WITH THIS SMALL WAVE...AND THE GFS
IS A BIT LESS SO...WITH A WEAKER BUT MORE DIFFUSE AND SLOWER
PASSAGE OF THE SFC SYSTEM UNTIL IT PASSES ILX FA. CONCERNS FOR THE
SOLUTION DIFFERENCES ARE MINIMAL AT THIS POINT...AS MAJORITY OF
THU AFTERNOON AND INTO THE EVENING ARE RAIN. SOLUTION DIFFERENCES
WILL LIKELY IMPACT QPF AS TIME GETS CLOSER. MAIN ISSUE WITH THIS
SYSTEM AT THIS POINT IS THE CONCERN FOR FZRA IN THE NRN HALF OF
THE CWA WITH THE MORNING PRECIP ON THURSDAY. NEXT SYSTEM OF
INTEREST WILL MOVE INTO THE REGION SAT/SUN CREATING THE POTENTIAL
FOR A MESSY WEEKEND. HOWEVER...THE HANDLING OF THE WAVE/TROF OVER
THE WEST VARIES WIDELY BTWN THE ECMWF AND THE GFS...AND FROM THEIR
PREVIOUS SOLUTIONS...AND WILL KEEP THE MENTION CONSERVATIVE FOR
NOW.
&&
.ILX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS LINCOLN IL
1045 AM CST MON FEB 4 2013
.DISCUSSION...
ISSUED 1045 AM CST MON FEB 4 2013
UPDATING THE FORECAST TO INCREASE HIGH TEMPERATURES A FEW MORE
DEGREES. A FEW CITIES HAVE ALREADY REACH CURRENT HIGH TEMPS OR
EVEN A DEGREE OR TWO ABOVE LIKE GALESBURG AND PEORIA. HIGHS TO
RANGE FROM THE MID 30S NW OF THE IL RIVER...TO 40-45F OVER SW
AREAS AND NEAR 40F IN SE IL. CONTINUED SLIGHT CHANCE OF LIGHT
RAIN/SNOW IN EASTERN IL ESPECIALLY THIS AFTERNOON. 1010 LOW
PRESSURE OVER WEST CENTRAL IL TO WEAKEN AS IT TRACKS ESE ACROSS
CENTRAL IL AND INTO THE CENTRAL OHIO VALLEY BY SUNSET. WINDS WILL
SHIFT AROUND TO THE NNW BEHIND THIS SYSTEM DURING THE COURSE OF
THE AFTERNOON BRINGING IN COOLER AIR.
07
&&
.AVIATION...
ISSUED 610 AM CST MON FEB 4 2013
UPDATED TAFS SHORTLY AFTER 12Z ISSUANCE TO INCLUDE LLWS FOR I-72
SITES. KILX 12Z SOUNDING INDICATES 40KTS AT 1400FT SUGGESTING THAT
MODELS ARE UNDERESTIMATING STRENGTH OF LOW-LEVEL JET AHEAD OF IOWA
SURFACE LOW. JET WILL LIKELY MIX OUT AND WEAKEN BY MIDDLE MORNING
AND WILL ONLY CARRY LLWS UNTIL 16Z.
ORIGINAL 12Z AVIATION AFD...
SURFACE LOW CURRENTLY CENTERED OVER SOUTHEAST IOWA IS EXPECTED TO
TRACK SOUTHEAST ALONG INTERSTATE 74 THROUGH THIS AFTERNOON. LOW
CLOUDS AND PCPN HAS BEEN CONFINED TO LOCATIONS NORTH OF THE
CENTRAL ILLINOIS TERMINALS WITH MID-DECKS IN PLACE. AS LOW MOVES
ACROSS THE AREA...LOW LEVEL MOISTURE WILL LIKELY ADVECT AROUND THE
LOW AND BRING IN MVFR CIGS AND WINDSHIFT TO THE NORTH. THIS SHOULD
OCCUR AT KPIA AND KBMI BY 18Z AND BY 20Z AT KCMI.
OVERNIGHT...WINDS WILL DIMINISH AS SURFACE RIDGING BUILDS INTO
ILLINOIS. THOUGH DEEP MOISTURE WILL LIKELY BE PUSHED EAST OF THE
AREA...HIGH BOUNDARY LAYER MOISTURE TRAPPED BELOW THE SUBSIDENCE
WILL LIKELY BE SUFFICIENT TO KEEP MVFR...AND ISOLATED IFR...CIGS
IN PLACE.
BARKER
&&
.PREV DISCUSSION...
ISSUED 306 AM CST MON FEB 4 2013
WEAK HIGH PRESSURE SLIDING EAST AS ANOTHER WAVE OF PRECIP MOVES
ACROSS NRN IL THIS MORNING. NOT QUITE OUT OF THE INFLUENCE OF THE
PATTERN JUST YET...THE FIRST COUPLE OF ISSUES FOR THE FORECAST ARE
THE NEXT CLIPPER SYSTEMS MOVING THROUGH THE MIDWEST UNTIL THE END
OF THE WEEK. CONSIDERING THE PATTERN...THE AGREEMENT BTWN THE
MODELS IS IMPRESSIVE. NOT A LOT OF CHANGE IN THE FORECAST OVERALL
AS SOME RUN TO RUN CONSISTENCY IN THE MED AND LONGER RANGE. SOME
MINOR ISSUES IN THE SHORT TERM WITH PRECIP TODAY. ANOTHER ISSUE
FOR AS A RESULT OF THE SERIES OF WAVES MOVING THROUGH...NON
DIURNAL TEMPS FOR A COUPLE OF PERIODS. OVERALL...FORECAST
REMAINING RATHER CONSISTENT.
SHORT TERM...TODAY AND TOMORROW...
SNOW AND ASSOCIATED SHORT WAVE TO THE NORTH THIS MORNING WAS
PREVIOUSLY SET TO COLLIDE WITH ANOTHER WAVE TO THE SOUTH MIDDAY.
HOWEVER...WAVE TO THE NORTH A LITTLE AHEAD OF SCHEDULE...WITH SFC
WAVE TO THE SOUTHWEST LAGGING A BIT BEHIND. HAVE PULLED POPS DOWN
A BIT TO REFLECT THE DROP IN PROBABILITY...KEEPING SLIGHTS IN THIS
MORNING FOR EASTERN HALF OF CWA. BUT THIS AFTERNOON MAY SEE A
BETTER CHANCE WITH THE SOUTHERN WAVE IN THE SE. NAM/ECMWF/GFS
TRENDING A LITTLE DRIER...AND THE RUC IS COMPLETELY DRY THIS
AFTERNOON UNTIL THE WAVE PULLS OUT LATER THIS AFTERNOON. TEMPS A
BIT WARMER TODAY AS WELL WITH A SOUTHERLY COMPONENT RETURNING TO
THE SFC FLOW...ALBEIT WEAK. TOMORROWS WAVE PASSING JUST TO THE
NORTH AND CHANCES FOR PRECIP CONFINED WELL TO THE NORTH
AGAIN...WITH SIMILAR TEMPS TOMORROW AS TODAY...WITH BREEZY
WESTERLY WINDS KEEPING SOME WARM AIR MOVING INTO THE CWA.
LONG TERM...WEDNESDAY THROUGH SUNDAY...
WEDNESDAY DRY AND WARM AGAIN AHEAD OF THE NEXT SYSTEM FOR WED
NIGHT INTO THURSDAY. THOUGH THREAT FROM THE WEST WILL INCREASE FOR
THE OVERNIGHT HOURS ON WED NIGHT...THE BEST CHANCES WILL COME WITH
THE PASSAGE OF THE SFC BOUNDARY ON THUR/THU NIGHT. LAST MODEL RUN
DIVERGES SOMEWHAT WITH THE SOLUTIONS FOR THIS PARTICULAR WAVE. A
TROF DEEPENS OVER THE WEST COAST...AND THIS PARTICULAR SYSTEM IS
A SMALL PIECE OF THE ENERGY EJECTING OUT AHEAD OF THE MAIN TROF.
THE ECMWF IS FAR MORE AMPLIFIED WITH THIS SMALL WAVE...AND THE GFS
IS A BIT LESS SO...WITH A WEAKER BUT MORE DIFFUSE AND SLOWER
PASSAGE OF THE SFC SYSTEM UNTIL IT PASSES ILX FA. CONCERNS FOR THE
SOLUTION DIFFERENCES ARE MINIMAL AT THIS POINT...AS MAJORITY OF
THU AFTERNOON AND INTO THE EVENING ARE RAIN. SOLUTION DIFFERENCES
WILL LIKELY IMPACT QPF AS TIME GETS CLOSER. MAIN ISSUE WITH THIS
SYSTEM AT THIS POINT IS THE CONCERN FOR FZRA IN THE NRN HALF OF
THE CWA WITH THE MORNING PRECIP ON THURSDAY. NEXT SYSTEM OF
INTEREST WILL MOVE INTO THE REGION SAT/SUN CREATING THE POTENTIAL
FOR A MESSY WEEKEND. HOWEVER...THE HANDLING OF THE WAVE/TROF OVER
THE WEST VARIES WIDELY BTWN THE ECMWF AND THE GFS...AND FROM THEIR
PREVIOUS SOLUTIONS...AND WILL KEEP THE MENTION CONSERVATIVE FOR
NOW.
&&
.ILX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS TOPEKA KS
344 PM CST MON FEB 4 2013
.DISCUSSION...
LATEST SURFACE ANALYSIS HAD HIGH PRESSURE BUILDING INTO NORTHEAST
KANSAS AT 20Z. STRATUS HAS BEEN ERODING NORTH OF INTERSTATE 70 THIS
AFTERNOON AREAS SOUTH OF I-70 HAVE REMAINED CLEAR TODAY.
LATEST RAP 13 RELATIVE HUMIDITY PLOTS KEEP THE LOWER LAYERS
SATURATED THROUGH THE EVENING. DEPENDING ON HOW WELL THE LOWER
BOUNDARY LAYER MIXES OUT THIS AFTERNOON...STATUS MAY MOVE BACK SOUTH
OR REFORM AFTER SUNSET. WILL KEEP SOME CLOUDS NORTH OF I-70 THIS
EVENING WITH MOSTLY CLEAR SKIES IN THE SOUTH. LOWS TONIGHT WILL
RANGE FROM THE LOWER 20S IN THE FAR NORTHEAST TO THE MID 20S
ELSEWHERE IN NORTHEAST...NORTH CENTRAL AND EAST CENTRAL KANSAS.
THE SURFACE HIGH MOVES OFF TO THE EAST TONIGHT WITH RETURN FLOW
OCCURRING AFTER 06Z TUESDAY. WARM ADVECTION OCCURS THROUGH MID DAY
TUESDAY BEFORE COOL ADVECTION OCCURS IN THE NORTHEAST IN THE
AFTERNOON. THEREFORE EXPECT THE COOLEST TEMPERATURES IN THE
NORTHEAST CORNER. THE HIGHS TUESDAY SHOULD RANGE FROM THE UPPER 40S
TO THE MID 50S.
53
.TUESDAY NIGHT THROUGH FRIDAY NIGHT...
RIDGING ALOFT WILL BUILD EASTWARD INTO THE PLAINS ON WEDNESDAY WITH
SOUTHERLY WINDS AND WARMER TEMPERATURES IN THE MIDDLE 50S NORTH TO
THE LOWER 60S SOUTH OF I 70. AS ANOTHER SHORTWAVE TROUGH NOW IN THE
PACIFIC ADVANCES QUICKLY EASTWARD INTO THE CENTRAL HIGH PLAINS...
IT WILL RESULT IN A RAPID RETURN OF MOISTURE NORTHWARD ACROSS
CENTRAL AND EASTERN KANSAS. AS A FRONT MOVES INTO THE CWA WEDNESDAY
EVENING...SHOWERS AND SOME ISOLATED THUNDERSTORMS ARE EXPECTED TO
DEVELOP WEST TO EAST THROUGH THE NIGHT...EXITING THE SOUTHEAST
CORNER OF THE COUNTY WARNING AREA BY MIDDAY THURSDAY AS THE FRONT
AND SHORTWAVE TROUGH PUSHES SOUTH AND EAST OF THE AREA.
.SATURDAY THROUGH MONDAY...
MODEL SOLUTIONS VARYING ON HOW THEY HANDLE THE WEEKEND TROUGH THAT
DIGS INTO THE DESERT SOUTHWEST AND EJECTS OUT INTO THE PLAINS OVER
THE WEEKEND. THE PRIMARY DIFFERENCES OCCUR IN REGARD TO HOW A
NORTHERN STREAM SHORTWAVE TROUGH MOVES INTO THE PLAINS IN PROXIMITY
TO THE SHARP TROUGH IN THE SOUTHWEST. THE GFS/ENSEMBLE MEMBERS ARE
TRENDING TOWARDS KEEP THIS TROUGH AHEAD OF THE SOUTHWEST TROUGH
WHICH RESULTS IN A WEAKER AND MORE POSITIVELY TILTED TROUGH ADVANCING
ACROSS THE PLAINS WHILE THE UKMET/GEM/EC CONTINUE MORE IN LINE WITH
PAST SOLNS IN EJECTING THE PRIMARY TROUGH OUT OF THE SOUTHWEST INTO
THE CENTRAL PLAINS. FOR NOW WILL KEEP MORE CONTINUITY WITH WITH
PREVIOUS FCSTS AND LEAN TOWARDS THE EC WHICH STILL BRINGS INCREASING
POTENTIAL FOR SHOWERS AND ISOLATED THUNDERSTORMS SATURDAY AND
ESPECIALLY SATURDAY NIGHT AND SUNDAY BEFORE A DRY SLOT AND COLDER
AIR WORK INTO THE CWA SUNDAY NIGHT WITH A DECREASING POTENTIAL FOR A
RAIN SNOW MIX SUNDAY NIGHT. EITHER WY...PRECIP SHOULD END BY MONDAY
MORNING AS THE SYSTEM LIFTS QUICKLY OFF TO THE NORTHEAST AND DRIER
AIR REMAINS ACROSS THE AREA THROUGH THE DAY. AFTER HIGHS IN THE 40S
AND MIDDLE 50S FOR SATURDAY AND SUNDAY...READINGS COOL INTO THE 40S
FOR HIGHS ON MONDAY. 63
&&
.AVIATION...
TRACKING A BAND OF LOW END MVFR STRATUS SLIDING SOUTH OVER
NORTHEAST KANSAS. THE BAND SHOULD ENTER KMHK FIRST BEFORE ENTERING
KTOP/KFOE SHORTLY NEAR 18Z. CIGS COULD WAVER ON THE LINE BETWEEN
MVFR AND IFR THROUGH THE AFTERNOON. UNCERTAINTY INCREASES IN
DURATION AND SOUTHERN EXTENT OF THIS STRATUS WITH MOST MODELS NOT
IN AGREEMENT WITH THE CURRENT OBSERVATIONS. CONFIDENCE FOR NOW WAS
PLACED WITH THE HRRR WHICH SHOWED THE BEST CONSISTENCY WITH STRONG
COLD ADVECTION ALOFT HOLDING THE MVFR STRATUS THRU 07Z AT KMHK AND
08Z AT KTOP/KFOE. NORTH WINDS AOA 10KTS THROUGH THE PERIOD WILL
BECOME LIGHT AND VARIABLE AFTER 00Z.
BOWEN
&&
.TOP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS GOODLAND KS
224 PM MST MON FEB 4 2013
.SHORT TERM...(THIS EVENING THROUGH TUESDAY)
ISSUED AT 1243 PM MST MON FEB 4 2013
LATEST WV IMAGERY AND RUC H5 ANALYSIS SHOW NW FLOW STILL IN PLACE
FROM BRITISH COLUMBIA ACROSS THE CENTRAL HIGH PLAINS INTO THE
SOUTHERN MISSISSIPPI RIVER VALLEY. LEE TROUGH REMAINS IN PLACE OVER
EASTERN COLORADO WITH ANOTHER WEAK TROUGH AXIS OVER NW KANSAS.
OTHER THAN PASSING HIGH CLOUDS WITHIN NW FLOW TONIGHT...THERE IS
WILL BE VERY LITTLE CHANGE IN EXPECTED CONDITIONS TONIGHT VERSUS
THE LAST FEW NIGHTS...WITH LOWS GENERALLY IN 20S ACROSS THE AREA.
A SHORTWAVE RIDGE WILL BEGIN TO BUILD OVER THE INTER-MOUNTAIN
WEST BY MIDDAY TUESDAY WITHIN PROGRESSIVE FLOW. THERE MAY BE WEAK
FORCING WITHIN THE VICINITY OF THE CWA TUESDAY AFTERNOON AS A
H7-H5 VORT MAX PROGRESSES ACROSS NORTHERN EXTENT OF RIDGE IN
RESPONSE TO A DEEPENING SHORTWAVE TROUGH OVER THE NORTHERN
ROCKIES. HOWEVER...WITH DEEP DRY AIR MASS IN PLACE THIS SHOULD ONLY
RESULT IN INCREASING HIGH CLOUD COVER BY LATE TUESDAY AFTERNOON.
WITH ALL OF THIS IN MIND...I AM ANTICIPATING MILD/DRY CONDITIONS
AGAIN ON TUESDAY WITH HIGHS IN THE MID-UPPER 50S.
.LONG TERM...(TUESDAY NIGHT THROUGH MONDAY)
ISSUED AT 223 PM MST MON FEB 4 2013
TUESDAY NIGHT-FRIDAY...SHORT WAVE RIDGE WILL BE IN PLACE ACROSS THE
AREA DURING THE THE BEGINNING OF THE PERIOD LEADING TO CONTINUED DRY
CONDITIONS THROUGH WEDNESDAY. A SHORT WAVE TROUGH WILL MOVE ACROSS
NEBRASKA ON WEDNESDAY...BUT GIVEN STABLE CONDITIONS EXPECTED ACROSS
THE AREA DO NOT EXPECT MUCH OF A RESPONSE ACROSS THE CWA. WHILE
MODELS SUGGEST INCREASE IN ELEVATED INSTABILITY OVERNIGHT WEDNESDAY
ACROSS SOUTHERN AND EASTERN KANSAS...AFOREMENTIONED TROUGH WILL
LIKELY FORCE H85 AND H7 FRONTAL ZONE WELL TO THE SOUTH OF THE AREA
WHICH WOULD MAKE PRECIPITATION DEVELOPING AS FAR NORTH OF THE CWA
UNLIKELY. OTHERWISE ABOVE NORMAL CONDITIONS ARE EXPECTED THROUGH THE
PERIOD.
IN THE EXTENDED(FRIDAY NIGHT-MONDAY)...MAIN CONCERN FOR THE PERIOD
WILL BE THE DEVELOPMENT AND EVOLUTION OF STRONG H5 TROUGH DURING THE
WEEKEND AND ASSOCIATED PRECIP/WINTER STORM IMPACTS THROUGH MONDAY.
THERE ARE TWO DISTINCT CAMPS WITH RESPECT TO 12Z OPERATIONAL AND
ENSEMBLE GUIDANCE. THE ECMWF/GEM AND GEM MEAN INDICATING A FARTHER
EAST MORE CONSOLIDATED SYSTEM IMPACTING THE AREA WHILE GFS AND
MAJORITY OF ITS ENSEMBLE MEMBERS SUGGESTING A FURTHER WEST SYSTEM
THAT IS SOMEWHAT SPLIT BETWEEN THE SOUTHWEST AND NORTHEAST. AT THIS
POINT...HARD TO PICK A FAVORITE CLUSTER WHILE TOTALLY IGNORING OTHER
POSSIBLE SCENARIO. THE ECMWF GROUP WOULD SUPPORT A SIG PRECIP THREAT
ACROSS NORTHERN CWA WHILE GFS SOLUTION WOULD RESULT IN MUCH LESS
PRECIP AND OVERALL SMALLER IMPACT. FOR THE TIME BEING...THINK
KEEPING POPS IN THE CHANCE RANGE IS WARRANTED AND STAYING TOWARDS
CONSENSUS DATA WARRANTED UNTIL BETTER SIGNAL DEVELOPS AND CONFIDENCE
INCREASES. GENERAL CONSENSUS SUGGEST MUCH ABOVE NORMAL TEMPERATURES
AND POSSIBLY A FEW THUNDERSTORMS MAY DEVELOP AHEAD OF SYSTEM BEFORE
SNOW DEVELOPS AS SYSTEM EXITS AND COLDER AIR MOVES IN. WHILE THERE
IS POTENTIAL FOR A SIGNIFICANT WINTER STORM...FOR REASONS MENTIONED
ABOVE FEEL IT IS TOO EARLY TO REALLY KEY IN ON THIS SOLUTION.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z TUESDAY AFTERNOON)
ISSUED AT 1031 AM MST MON FEB 4 2013
VFR CONDITIONS WILL PERSIST THROUGH THE TAF PERIOD AT GLD AND MCK. A
FEW HIGH TO MID-LEVEL CLOUDS THIS AFTERNOON AND INTO THE EVENING
FOLLOWED BY MAINLY CLEAR SKIES LATE TONIGHT AND THROUGH TOMORROW.
LIGHT/VARIABLE WINDS WILL PICK UP OUT OF THE WEST TO NORTHWEST LATER
TODAY AND THROUGH THE REST OF THE TAF PERIOD.
&&
.GLD WATCHES/WARNINGS/ADVISORIES...
KS...NONE.
CO...NONE.
NE...NONE.
&&
$$
SHORT TERM...DR
LONG TERM...JRM
AVIATION...JJM
AREA FORECAST DISCUSSION
NWS GOODLAND KS
1243 PM MST MON FEB 4 2013
.SHORT TERM...(THIS EVENING THROUGH TUESDAY)
ISSUED AT 1243 PM MST MON FEB 4 2013
LATEST WV IMAGERY AND RUC H5 ANALYSIS SHOW NW FLOW STILL IN PLACE
FROM BRITISH COLUMBIA ACROSS THE CENTRAL HIGH PLAINS INTO THE
SOUTHERN MISSISSIPPI RIVER VALLEY. LEE TROUGH REMAINS IN PLACE OVER
EASTERN COLORADO WITH ANOTHER WEAK TROUGH AXIS OVER NW KANSAS.
OTHER THAN PASSING HIGH CLOUDS WITHIN NW FLOW TONIGHT...THERE IS
WILL BE VERY LITTLE CHANGE IN EXPECTED CONDITIONS TONIGHT VERSUS
THE LAST FEW NIGHTS...WITH LOWS GENERALLY IN 20S ACROSS THE AREA.
A SHORTWAVE RIDGE WILL BEGIN TO BUILD OVER THE INTER-MOUNTAIN
WEST BY MIDDAY TUESDAY WITHIN PROGRESSIVE FLOW. THERE MAY BE WEAK
FORCING WITHIN THE VICINITY OF THE CWA TUESDAY AFTERNOON AS A
H7-H5 VORT MAX PROGRESSES ACROSS NORTHERN EXTENT OF RIDGE IN
RESPONSE TO A DEEPENING SHORTWAVE TROUGH OVER THE NORTHERN
ROCKIES. HOWEVER...WITH DEEP DRY AIR MASS IN PLACE THIS SHOULD ONLY
RESULT IN INCREASING HIGH CLOUD COVER BY LATE TUESDAY AFTERNOON.
WITH ALL OF THIS IN MIND...I AM ANTICIPATING MILD/DRY CONDITIONS
AGAIN ON TUESDAY WITH HIGHS IN THE MID-UPPER 50S.
.LONG TERM...(THURSDAY THROUGH MONDAY)
ISSUED AT 1223 AM MST MON FEB 4 2013
SHORTWAVE RIDGING WILL REMAIN IN PLACE FOR THURSDAY AND FRIDAY
LEADING TO DRY CONDITIONS AND ABOVE NORMAL TEMPERATURES. WESTERN
DISTURBANCE WILL BRING A CHANCE FOR RAIN AND SNOW OVER THE
WEEKEND. MODEL RUNS ARE IN EVEN LESS AGREEMENT TONIGHT WITH
DETAILS SUCH AS TRACK...STRENGTH AND TIMING. ECMWF SHOWS A DEEP
CUT OFF LOW DEVELOPING OVER SOUTHWEST KANSAS ON SUNDAY WHICH WOULD
BRING WIND AND SNOW. HOWEVER...THE GFS NEVER DEVELOPS A CUT OFF
INSTEAD SHOWING AN OPEN WAVE AND LITTLE TO NO PRECIPITATION. SOME
POPS ARE PROBABLY WARRANTED...BUT CONFIDENCE IN THE DETAILS IS
VERY VERY LOW AT THIS POINT.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z TUESDAY AFTERNOON)
ISSUED AT 1031 AM MST MON FEB 4 2013
VFR CONDITIONS WILL PERSIST THROUGH THE TAF PERIOD AT GLD AND MCK. A
FEW HIGH TO MID-LEVEL CLOUDS THIS AFTERNOON AND INTO THE EVENING
FOLLOWED BY MAINLY CLEAR SKIES LATE TONIGHT AND THROUGH TOMORROW.
LIGHT/VARIABLE WINDS WILL PICK UP OUT OF THE WEST TO NORTHWEST LATER
TODAY AND THROUGH THE REST OF THE TAF PERIOD.
&&
.GLD WATCHES/WARNINGS/ADVISORIES...
KS...NONE.
CO...NONE.
NE...NONE.
&&
$$
SHORT TERM...DR
LONG TERM...024
AVIATION...JJM
AREA FORECAST DISCUSSION
NWS TOPEKA KS
1141 AM CST MON FEB 4 2013
...UPDATE TO AVIATION...
.DISCUSSION...
INVERTED SURFACE TROF BISECTING THE FORECAST AREA THIS
MORNING...WITH COLDER AIR STILL TO THE NORTH AT THIS HOUR. UPPER
WAVE MOVING THROUGH NORTHWEST KANSAS TO THE SOUTHEAST AND WILL SWEEP
COLD FRONT ACROSS THE FORECAST AREA THROUGH THE DAY TODAY.
TEMPERATURES EXPECTED TO STAY WELL MIXED INTO THE 40S FOR THE EAST
CENTRAL COUNTIES UNTIL THIS AFTERNOON WHEN FRONT COMES
THROUGH...WITH NORTH CENTRAL COUNTIES STARTING OFF IN THE LOW TO
MIDDLE 30S BUT DROPPING SLOWLY AS THE DAY GOES ON.
ALSO KEEPING AN EYE ON THE CLOUD DECK MOVING QUICKLY SOUTH OUT OF
SOUTH DAKOTA AND NORTHEAST NEBRASKA. RAP RH CHARTS BRING THIS DECK
INTO THE I70 CORRIDOR AROUND THE NOON HOUR BEFORE BREAKING UP AS IT
MOVES SOUTHWARD. FAR NORTHEAST COUNTIES EXPECTED TO REMAIN THE
COOLEST WITH TEMPERATURES IN THE MIDDLE 30S AND FALLING THIS
AFTERNOON. WINDS BECOME BREEZY FROM THE NORTH FOR A TIME AS THE
FRONT PUSHES THROUGH...BUT THEN WINDS LIGHTEN AND VEER AROUND TO THE
SOUTHWEST BY EARLY MORNING HOURS. OVERNIGHT LOWS SHOULD DROP INTO
THE 20S MOST AREAS AS THE WINDS DIMINISH AND CLOUDS DECREASE.
67
TUESDAY AND WEDNESDAY...ANOTHER WEAK COLD FRONT WILL PUSH THROUGH
TUESDAY AS NORTHWEST FLOW CONTINUES ALOFT. SURFACE HIGH PRESSURE
MOVES RAPIDLY EAST TUESDAY NIGHT ALLOWING WAA TO ONCE AGAIN
RETURN. HOWEVER...WAA NOT STRONG INITIALLY ON WEDNESDAY AFTERNOON
WITH ONLY A MODEST INCREASE IN 850MB TEMPS OF ABOUT 2-3C AND A
3-4DM INCREASE IN HEIGHTS. 925MB-850MB TRANSPORT WINDS WILL BE
AROUND 20-25KTS FROM THE SOUTH/SOUTHEAST...AND WILL ADVECT A
DECENT MOISTURE PLUME NORTH INTO THE CWA AHEAD OF ANOTHER
ADVANCING COLD FRONT FOR WEDNESDAY NIGHT AND INTO THURSDAY
MORNING. WEDNESDAY LOOKS TO BE THE WARMEST DAY OF THE WEEK WITH
HIGHS APPROACHING OR TOPPING 60.
WEDNESDAY NIGHT AND THURSDAY...PW VALUES INCREASE TO AROUND AN
INCH FOR LATE WEDNESDAY NIGHT FOR AREAS MAINLY SOUTH OF INTERSTATE
70. INCREASED POPS AS MODELS COMING INTO AGREEMENT AS FAR AS
PLACEMENT. HOWEVER...MODELS DO DIVERGE ON QPF WITH THE NAM BEING
VERY AGGRESSIVE WITH A BULLS EYE OVER THE SOUTHERN PORTION OF THE
CWA OF AN INCH OF PRECIP. FEEL THIS IS A BIT OVERDONE...AND HAVE
GONE WITH THE MORE CONSISTENT AND CONSERVATIVE QPF VALUES OF THE
ECMWF AND GFS. NAM QUITE AGGRESSIVE ON MUCAPE VALUES AS WELL WITH
UP TO 500 J/KG. MENTIONED ISOLATED THUNDER WEDNESDAY NIGHT SOUTH
OF INTERSTATE 70...BUT FEEL THE NAM INSTABILITY VALUES A BIT
INFLATED. SHEAR PROFILES LOOK TO SUPPORT THUNDER AS WELL WITH
0-6KM VALUES OF AROUND 40KTS. THE SYSTEM SHOULD CLEAR THE CWA BY
18Z. TEMPERATURES WILL BE SLIGHTLY COOLER BEHIND THE FRONT OF
AROUND 10 DEGREES...AND WITH SKIES CLEARING OUT QUICKLY...SHOULD
SEE A RETURN TO 40`S AND 50`S BY THURSDAY AFTERNOON.
EXTENDED...(THURSDAY NIGHT THROUGH THE WEEKEND)...NEXT SYSTEM TO
AFFECT THE REGION WILL BE SATURDAY. QUITE A BIT OF DIVERGENCE IN
THE MODELS AT THIS TIME AS TO THE EVOLUTION OF THE SYSTEM AND ITS
IMPACT ON THE PLAINS. THE GFS ESSENTIALLY HAS THE SYSTEM BECOME
CUTOFF OVER THE DESERT SOUTHWEST AS THE NORTHERN STREAM OF THE
JET PINCHES IT OFF OVER THAT REGION OF THE COUNTRY WITH A FAST
MOVING SHRTWV ACROSS THE NORTHERN PLAINS. THE ECMWF HAS THE SYSTEM
MOVE RAPIDLY OUT OF THE DESERT SOUTHWEST AS A CLOSED H5 LOW RIGHT
ACROSS KANSAS. GIVEN THE EVOLUTION OF SYSTEMS THIS PAST WINTER
SEASON...FEEL THE ECMWF SCENARIO NOT LIKELY. HOWEVER...LOWERED
POPS A BIT SATURDAY TO REFLECT THE DISAGREEMENT IN MODELS. BEHIND
THE SYSTEM...PROFILES LOOK COLD ENOUGH TO BEGIN SUPPORTING SLEET
OR SNOW OVER THE NORTHWEST COUNTIES BY SUNDAY AFTERNOON.
01
&&
.AVIATION...
TRACKING A BAND OF LOW END MVFR STRATUS SLIDING SOUTH OVER
NORTHEAST KANSAS. THE BAND SHOULD ENTER KMHK FIRST BEFORE ENTERING
KTOP/KFOE SHORTLY NEAR 18Z. CIGS COULD WAVER ON THE LINE BETWEEN
MVFR AND IFR THROUGH THE AFTERNOON. UNCERTAINTY INCREASES IN
DURATION AND SOUTHERN EXTENT OF THIS STRATUS WITH MOST MODELS NOT
IN AGREEMENT WITH THE CURRENT OBSERVATIONS. CONFIDENCE FOR NOW WAS
PLACED WITH THE HRRR WHICH SHOWED THE BEST CONSISTENCY WITH STRONG
COLD ADVECTION ALOFT HOLDING THE MVFR STRATUS THRU 07Z AT KMHK AND
08Z AT KTOP/KFOE. NORTH WINDS AOA 10KTS THROUGH THE PERIOD WILL
BECOME LIGHT AND VARIABLE AFTER 00Z.
BOWEN
&&
.TOP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
423 PM EST MON FEB 4 2013
.SHORT TERM...(THIS EVENING THROUGH TUESDAY)
ISSUED AT 423 PM EST MON FEB 4 2013
LIGHT TO MODERATE SNOW WITH A CLIPPER SYSTEM WILL BE THE MAIN STORY
IN THE SHORT TERM.
LATE THIS AFTERNOON...BACKING WINDS TO A WESTERLY DIRECTION ARE
PUSHING REMAINING LES OFFSHORE ACROSS EASTERN UPPER MI...WITH A FEW
TRANSIENT LES BANDS REMAINING NEAR THE SHORE. HAVE THUS CANCELED THE
LES WARNING...THOUGH A COUPLE MORE INCHES OF SNOW WILL BE POSSIBLE
THROUGH THIS EVENING.
TONIGHT...CLEARING SKIES AND LIGHT WINDS WILL ALLOW FOR QUICK
RADIATIONAL COOLING EARLY THIS EVENING...ESPECIALLY ACROSS CENTRAL
AND EASTERN UPPER MI. LOWERED THE MIN TEMPS GIVEN A SIMILAR SETUP TO
LAST NIGHTS SUBSTANTIAL COOLING.
MAIN FOCUS IS ON A WEAK CLIPPER SYSTEM MOVING SOUTHEAST ACROSS THE
UPPER GREAT LAKES TONIGHT INTO TUESDAY. MODEL AGREEMENT HAS BEEN A
LITTLE FUZZY...WITH THE RUC PLACING THE BULK OF PRECIP IN UPPER
MI...THE NAM AND REGIONAL GEM PUTTING MOST ALONG THE WI BORDER...AND
THE GFS PLACING NEARLY ALL PRECIP IN NORTHERN WI. HAVE OPTED TO GO
WITH THE MIDDLE GROUND AS THE CONSENSUS TREND HAS BEEN TO BRING
THINGS SLIGHTLY NORTH.
PRECIP WILL BE FOCUSED ALONG AN AREA OF 850 TO 700MB FRONTOGENESIS.
THE MOST ACTIVE LAYER IS NOT CLEAR...BUT BELIEVE THE BEST FORCING
WILL BE BETWEEN 750 AND 800MB. A FAIRLY DECENT LAYER OF 150 TO 200MB
WITHIN THE BEST RISING MOTION WILL BE IN THE DGZ. BOOSTED SNOW
RATIOS TO THE LOW 20S GIVEN THIS SET UP. OVERALL...KEPT TOTAL QPF OF
0.1 TO 0.2 INCHES...PRODUCING 1 TO 3 INCHES...WITH UP TO 4 INCHES
POSSIBLE. CURRENT THINKING IS THAT THE HIGHEST AMOUNTS WILL BE ALONG
THE WI BORDER...THOUGH WOULD NOT BE SURPRISED IF IT IS PUSHES 50
MILES EITHER WAY GIVEN THE MODEL INCONSISTENCIES AND NARROW FEATURE.
HAVE ISSUED AN SPS TO COVER THE EVENT AS THERE IS TOO LOW OF
CONFIDENCE TO PUT IN ANY ADVISORIES ATTM. EXPECT SNOW TO BEGIN
ACROSS THE WEST AROUND MIDNIGHT AND SPREAD EAST OVERNIGHT.
THE MAIN SNOW SHIELD WILL DIMINISH THROUGHOUT THE MORNING. THEN...A
WELL DEFINED TROUGH BEHIND THE LOW WILL MOVE SOUTH ACROSS THE
NORTHERN CWA IN THE AFTERNOON. WOULD NOT BE SURPRISED IF A QUICK
BURST OF HEAVY SNOW ACCOMPANIES THIS TROUGH.
.LONG TERM...(TUESDAY NIGHT THROUGH MONDAY)
ISSUED AT 423 PM EST MON FEB 4 2013
NORTHWEST FLOW ALOFT WILL BE IN PLACE FOR THE START OF THE
PERIOD...AS A RIDGE REMAINS IN PLACE OVER THE WESTERN CONUS AND A
TROUGH IS SETUP IN EASTERN CANADA. WITH NORTHWEST FLOW AND H850
TEMPS AROUND -19C...EXPECT SOME LAKE EFFECT SNOW BEHIND THE CLIPPER
SYSTEM THAT MOVES THROUGH ON TUESDAY. THINKING THERE WILL BE ENOUGH
MOISTURE LEFT BEHIND THE CLIPPER TO LEAD TO A BRIEF UPTICK IN THE
LAKE EFFECT INTENSITY DURING THE LATER HALF OF THE EVENING AND INTO
THE FIRST PART OF THE OVERNIGHT HOURS. DON/T EXPECT ANYTHING TOO
SIGNIFICANT DUE TO WEAKENING WINDS WITH THE APPROACHING
SURFACE RIDGE AND INVERSION HEIGHTS IN THE 5-7KFT RANGE...BUT WITH
THE DGZ LOCATED RIGHT IN THE BEST OMEGA AND CLOUD LAYER...WOULD
THINK THAT THE NORTHWEST WIND FAVORED LOCATIONS WOULD SEE A DUSTING
TO A FLUFFY COUPLE OF INCHES OF SNOW.
THE SURFACE RIDGE WILL LEAD TO MORE VARIABLE AND BACKING WINDS
TOWARDS WEDNESDAY MORNING...WHILE THE NEXT CLIPPER SYSTEM
APPROACHES FROM THE DAKOTAS ON WEDNESDAY. THE INCREASING SOUTHERLY
FLOW WILL LEAD TO WARM AIR ADVECTION CLOUDS AND PRECIPITATION
SPREADING ACROSS WEDNESDAY INTO WEDNESDAY NIGHT...WITH THE LOW
MOVING THROUGH THE GREAT LAKES REGION LATE WEDNESDAY NIGHT INTO
THURSDAY. MODELS SEEM FAIRLY CONSISTENT ON THE SHORTWAVE PRODUCING
THIS FEATURE MOVING THROUGH WISCONSIN...ALONG WITH THE BEST/SHARPEST
LOWER LEVEL FORCING. BUT EXPECT THERE TO BE ENOUGH WAA AND MID LEVEL
FGEN TO LEAD SNOW ALONG AND NORTH OF THE WARM FRONT. SEEMS LIKE THE
BEST MID LEVEL FGEN IS FAIRLY PROGRESSIVE ACROSS THE CWA...BUT DOES
TRY TO PIVOT SOMEWHAT ACROSS NORTHERN LAKE SUPERIOR AND NEAR THE
KEWEENAW PENINSULA. WILL BE INTERESTING TO SEE IF THIS PIVOT
CONTINUES AND WHERE IT LINES UP IN FUTURE RUNS...AS IT COULD LEAD TO
SOME INCREASING SNOWFALL AMOUNTS. IN ADDITION...WITH THE SOUTHERLY
LOW LEVEL WIND AND H850 TEMPS AROUND -9C SHOULD BE ENOUGH FOR LAKE
ENHANCEMENT OFF LAKE MICHIGAN. WIND FIELDS VARY FAIRLY SIGNIFICANTLY
IN THE MODELS...SO DIDN/T TRY TO GET TOO SPECIFIC OTHER THAN
TWEAKING POPS/QPF UP SLIGHTLY IN SCHOOLCRAFT/LUCE COUNTIES.
OTHERWISE...OVERALL CONSENSUS OF THE MODELS LOOKS TO PRODUCE
0.15-0.25 INCHES OF QPF...WITH THE HIGHEST AMOUNTS OVER THE
SOUTH/EASTERN CWA. THIS DOES SEEM TO MATCH UP WITH THE NORTH EDGE OF
THE BETTER H850-700 WAA AND RESULTING FGEN...ALONG WITH THE RIGHT
REAR OF THE UPPER JET. THIS PRODUCES A GENERAL 2-4INCHES OF SNOW
ACROSS THE AREA AND WILL CONTINUE TO MENTION IN THE HWO.
BEHIND THE CLIPPER...THERE DOESN/T LOOK TO BE MUCH COLD AIR SURGING
IN DUE TO THE UPPER RIDGE SHIFTING EAST AS AN UPPER TROUGH DIGS
INTO THE WEST COAST. THINKING THIS WILL LEAD TO A QUIETER PERIOD
FOR FRIDAY INTO THE FIRST PART OF SATURDAY AS A HIGH PRESSURE
RIDGE NEAR JAMES BAY STRETCHES SOUTHWEST ACROSS THE UPPER GREAT
LAKES. WITH LIMITED COLD AIR AND WINDS BACKING TO THE
SOUTHWEST...EXPECT A DIMINISHING TREND TO ANY LAKE EFFECT ON
THURSDAY NIGHT AND WILL GO WITH DRY CONDITIONS ON FRIDAY AND FRIDAY
NIGHT.
NEXT SHORTWAVE WILL BRUSH NORTHERN LAKE SUPERIOR ON SATURDAY AND
DRAG A SURFACE TROUGH ACROSS THE CWA. THIS SHOULD LEAD TO A LIGHT
DUSTING OF SNOW...WITH MOST LOCATIONS SEEING LESS THAN AN INCH.
AFTER THIS SYSTEM THE FORECAST BECOMES UNCERTAIN...AS MODELS DIFFER
IN HOW THE ENERGY EJECTS OUT OF THE UPPER TROUGH IN THE SW CONUS.
WILL CONTINUE TO FOLLOW A GENERAL CONSENSUS FOR POPS...WITH THE BEST
CHANCES FOR ACCUMULATING SNOW OVER THE SOUTHEAST HALF OF THE CWA.
AS FOR TEMPS...THE LONG TERM PART OF THE FORECAST LOOKS TO BE AT OR
SLIGHTLY ABOVE NORMAL FOR TEMPERATURES WITH THE COLDEST DAY/NIGHT
ON TUESDAY NIGHT AND WEDNESDAY.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z TUESDAY AFTERNOON)
ISSUED AT 1246 PM EST MON FEB 4 2013
LAKE EFFECT SNOW SHOWERS WILL CONTINUE TO WANE THROUGHOUT THE
AFTERNOON AT CMX...WHILE CONDITIONS REMAIN VFR AT IWD INTO THE
EVENING. MEANWHILE...MVFR DIURNAL STRATOCUMULUS HAVE STARTED TO
DEVELOP AT SAW...BUT SHOULD REMAIN MOSTLY SCATTERED.
THE MAIN FOCUS IS ON LOW PRESSURE MOVING ACROSS THE AREA TONIGHT.
FLUFFY...HIGH LIQUID RATIO SNOWFALL IS EXPECTED...MAINLY BETWEEN 06
AND 12Z AT IWD. VIS SHOULD FALL TO LOW END IFR AT IWD FOR SEVERAL
HOURS LATE TONIGHT. AT CMX AND SAW...EXPECT LOW END MVFR VIS AND
CIGS. WINDS WILL BE RELATIVELY LIGHT AS THE SNOW FALLS...SO BLSN IS
NOT A CONCERN. EXPECT WINDS TO TURN MORE OUT THE OF NORTH AT ALL
SITES BY LATE TUESDAY MORNING...LEADING TO FALLING CIGS FROM UPSLOPE
AT SAW AND IWD.
&&
.MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 423 PM EST MON FEB 4 2013
EXPECT WEST WINDS OF UNDER 25 KNOTS TO SLOWLY DIMINISH THROUGHOUT
THE NIGHT ACROSS THE EASTERN LAKE. WINDS WILL THEN VEER NORTH TO 20
TO 30 KNOTS BEHIND A TROUGH TUESDAY AFTERNOON INTO TUESDAY EVENING.
OTHERWISE...PLAN ON WINDS UNDER 20 KNOTS THROUGH THE REST OF THE
PERIOD.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...TK
LONG TERM...SRF
AVIATION...TK
MARINE...TK
AREA FORECAST DISCUSSION
NWS GRAND RAPIDS MI
1220 PM EST MON FEB 4 2013
.SYNOPSIS...
ISSUED AT 343 AM EST MON FEB 4 2013
LIGHT SNOW WILL CONTINUE INTO THE AFTERNOON TODAY AS A A CLIPPER
MOVES BY TO THE SOUTH OF THE CWA. AN INCH OR TWO OF ADDITIONAL
ACCUMULATION IS POSSIBLE TODAY BEFORE THE SNOW DIMINISHES. A
STRONGER CLIPPER WILL MOVE ACROSS THE CWA TUESDAY RESULTING IN
ANOTHER 1 TO 4 INCHES OF SNOW. MODERATING TEMPERATURES TOWARD THE
END OF THE WEEK MAY RESULT IN MIXED RAIN AND SNOW OVER THE WEEKEND.
&&
.UPDATE...
ISSUED AT 1109 AM EST MON FEB 4 2013
I HAVE NOW SHORTENED THE LAKE EFFECT SNOW ADVISORY SO IT NOW ENDS
AT 1 PM AS I SUGGESTED I WOULD IN MY PRIOR UPDATE.
UPDATE ISSUED AT 1032 AM EST MON FEB 4 2013
MY CURRENT THINKING IS TO DROP THE LAKE EFFECT SNOW ADVISORY AT 1
PM WITH THE WINTER WEATHER ADVISORY SINCE SURFACE WINDS WILL BE
FROM THE NORTH NORTHEAST... THAT IS NOT SUPPORTIVE OF LAKE EFFECT
SNOW. ALSO THE LATEST RAP MODEL DATA SHOWS LITTLE IF ANY LIFT
ALONG THE LAKE SHORE THIS AFTERNOON AS WELL AS LITTLE IF ANY QPF.
SO ONCE THE SYNOPTIC SYSTEM EXITS IN EARLY THIS AFTERNOON THE SHOW
IS OVER FOR THIS EVENT.
IT LOOKS TO ME LIKE TOMORROW WE WILL HAVE A SW FLOW ENHANCED EVENT
WITH THE NW LAKE SHORE AREAS GETTING THE MOST SNOW. SINCE I DO NOT
WANT HEADLINES FOR TODAY`S EVENT MIXED WITH TOMORROW I PLAN ON
PUTTING THE LAKE EFFECT SNOW ADVISORY (MKG TO LDM ONE ROW OF
COUNTIES) OUT WITH THE 4 PM FORECAST.
&&
.SHORT TERM...(TODAY THROUGH WEDNESDAY)
ISSUED AT 343 AM EST MON FEB 4 2013
FORECAST CONCERNS DEAL WITH SNOW TRENDS TODAY AND TUESDAY.
REGIONAL RADAR SHOWS SNOW FALLING ACROSS THE SRN CWA WNWWD ACROSS
SRN WISCONSIN. ANOTHER INCH OR TWO OF ACCUMULATION IS POSSIBLE AS
THE SYSTEM PASSES BY. LOWEST CONDENSATION PRESSURE DEFICITS ARE
SOUTH OF I-96 TODAY WHICH IS WHERE WE HAVE THE GREATEST
ACCUMULATION. AS THE CLIPPER PASSES BY SNOW WILL TAPER THIS
AFTERNOON. THE SYNOPTIC SNOW IS GETTING A BOOST FROM THE WESTERLY
WIND OFF THE LAKE.
WE MAY SEE A 6 OR 8 HR BREAK FROM SNOW BEFORE THE NEXT CLIPPER
ARRIVES LATE TONIGHT. THE CLIPPER IS PROGD MOVE OVER THE CWA TUESDAY
RESULTING IN A 1-3/2-4 INCH TYPE EVENT. THE LIGHT WINDS EXPECTED
TODAY SHOULD RESULT IN A LOWER IMPACT EVENT. DRY WX EXPECTED
WEDNESDAY AS ZONAL FLOW DEVELOPS IN THE WAKE OF THE CLIPPER.
.LONG TERM...(WEDNESDAY NIGHT THROUGH SUNDAY)
ISSUED AT 343 AM EST MON FEB 4 2013
ZONAL FLOW STILL LOOKS TO BE THE PREDOMINATE UPPER PATTERN TYPE
THROUGH THE LONG TERM PERIOD. MAIN FEATURES TO KEY ON ARE A
SHORTWAVE TROUGH FORECAST TO SWING THROUGH THE GREAT LAKES THURSDAY
AND ANOTHER DEEPER TROUGH CENTERED AROUND SUNDAY. 850MB ARE FORECAST
TO BE BETWEEN -8C AND +4C MUCH OF THE LONG TERM WHICH WILL TAKE LAKE
EFFECT OUT OF PLAY...WHICH WILL BE A CHANGE FROM THE CURRENT AND
RECENT PAST. TEMPERATURES THROUGH THE PERIOD WILL BE NEAR TO ABOVE
NORMAL.
AS FOR THE DETAILS...HAVE A CHANCE OF SNOW MENTIONED WEDNESDAY NIGHT
AHEAD OF A SURFACE TROUGH. HAVE TRENDED POPS TO LIKELY FOR THE BULK
OF THE CWA ON THURSDAY. MAINTAINED A POSSIBLE MIX WITH RAIN IN THE
SOUTH AS 850MB TEMPS TRY TO FLIRT WITH +2C PER THE ECMWF. THE SYSTEM
MOVES EAST THURSDAY NIGHT TAKING THE PRECIPITATION WITH IT. DRY
WEATHER IS ANTICIPATED FOR FRIDAY THROUGH SATURDAY NIGHT AS HIGH
PRESSURE SLIDES THROUGH THE REGION.
THE SUNDAY SYSTEM IS ASSOCIATED WITH UPPER SOUTHWEST FLOW IN PLACE.
THE ECMWF HAS MORE OF A SOUTHERN STREAM LOW EJECTING OUR DIRECTION.
AT THIS POINT HAVE RAIN AND SNOW MENTIONED. IT APPEARS SUNDAY MAY BE
TRENDING TOWARD A COLD RAIN. GIVEN THE TIME FRAME THOUGH...DEEP INTO
THE LONG TERM...WILL MAINTAIN A MIX AS THE ZERO C 850MB ISOTHERM IS
IN THE CWA PER BOTH THE GFS AND THE ECMWF.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z TUESDAY)
ISSUED AT 1220 PM EST MON FEB 4 2013
LIGHT SNOW SHOWERS WILL GRADUALLY TAPER OFF TO FLURRIES BEFORE
ENDING FROM WEST TO EAST THIS AFTERNOON. PREDOMINANTLY IFR/MVFR
CONDITIONS EARLY THIS AFTERNOON WILL TRANSITION TO MAINLY MVFR THEN
VFR THIS EVENING.
THE NEXT CLIPPER SYSTEM WILL BRING SNOW INTO KMKG VERY LATE TONIGHT.
SNOW WILL NOT DEVELOP IN KGRR AND TO THE EAST/SE/SOUTH OF KGRR UNTIL
THE LATE MORNING/EARLY AFTERNOON HOURS TUESDAY. THIS BATCH OF SNOW
WILL CAUSE CONDITIONS TO DETERIORATE BACK INTO THE MVFR THEN IFR
FLIGHT CATEGORY TUESDAY.
&&
.MARINE...
ISSUED AT 343 AM EST MON FEB 4 2013
DISCONTINUED THE SCA AS WINDS AND WAVES ARE LIKELY BELOW CRITERIA.
&&
.HYDROLOGY...
ISSUED AT 343 AM EST MON FEB 4 2013
WARMER WX IS EXPECTED TOWARD THE END OF THE WEEK. THIS MAY
EXACERBATE THE ICE JAM POTENTIAL.
&&
.GRR WATCHES/WARNINGS/ADVISORIES...
MI...WINTER WEATHER ADVISORY UNTIL 1 PM EST THIS AFTERNOON FOR
MIZ073-074.
LAKE EFFECT SNOW ADVISORY UNTIL 1 PM EST THIS AFTERNOON FOR
MIZ056-064-071-072.
LM...NONE.
&&
$$
UPDATE...WDM
SYNOPSIS...93
SHORT TERM...93
LONG TERM...DUKE
AVIATION...LAURENS
HYDROLOGY...93
MARINE...93
AREA FORECAST DISCUSSION
NWS GRAND RAPIDS MI
1111 AM EST MON FEB 4 2013
.SYNOPSIS...
ISSUED AT 343 AM EST MON FEB 4 2013
LIGHT SNOW WILL CONTINUE INTO THE AFTERNOON TODAY AS A A CLIPPER
MOVES BY TO THE SOUTH OF THE CWA. AN INCH OR TWO OF ADDITIONAL
ACCUMULATION IS POSSIBLE TODAY BEFORE THE SNOW DIMINISHES. A
STRONGER CLIPPER WILL MOVE ACROSS THE CWA TUESDAY RESULTING IN
ANOTHER 1 TO 4 INCHES OF SNOW. MODERATING TEMPERATURES TOWARD THE
END OF THE WEEK MAY RESULT IN MIXED RAIN AND SNOW OVER THE WEEKEND.
&&
.UPDATE...
ISSUED AT 1109 AM EST MON FEB 4 2013
I HAVE NOW SHORTENED THE LAKE EFFECT SNOW ADVISORY SO IT NOW ENDS
AT 1 PM AS I SUGGESTED I WOULD IN MY PRIOR UPDATE.
UPDATE ISSUED AT 1032 AM EST MON FEB 4 2013
MY CURRENT THINKING IS TO DROP THE LAKE EFFECT SNOW ADVISORY AT 1
PM WITH THE WINTER WEATHER ADVISORY SINCE SURFACE WINDS WILL BE
FROM THE NORTH NORTHEAST... THAT IS NOT SUPPORTIVE OF LAKE EFFECT
SNOW. ALSO THE LATEST RAP MODEL DATA SHOWS LITTLE IF ANY LIFT
ALONG THE LAKE SHORE THIS AFTERNOON AS WELL AS LITTLE IF ANY QPF.
SO ONCE THE SYNOPTIC SYSTEM EXITS IN EARLY THIS AFTERNOON THE SHOW
IS OVER FOR THIS EVENT.
IT LOOKS TO ME LIKE TOMORROW WE WILL HAVE A SW FLOW ENHANCED EVENT
WITH THE NW LAKE SHORE AREAS GETTING THE MOST SNOW. SINCE I DO NOT
WANT HEADLINES FOR TODAY`S EVENT MIXED WITH TOMORROW I PLAN ON
PUTTING THE LAKE EFFECT SNOW ADVISORY (MKG TO LDM ONE ROW OF
COUNTIES) OUT WITH THE 4 PM FORECAST.
&&
.SHORT TERM...(TODAY THROUGH WEDNESDAY)
ISSUED AT 343 AM EST MON FEB 4 2013
FORECAST CONCERNS DEAL WITH SNOW TRENDS TODAY AND TUESDAY.
REGIONAL RADAR SHOWS SNOW FALLING ACROSS THE SRN CWA WNWWD ACROSS
SRN
WISCONSIN. ANOTHER INCH OR TWO OF ACCUMULATION IS POSSIBLE AS THE
SYSTEM PASSES BY. LOWEST CONDENSATION PRESSURE DEFICITS ARE SOUTH OF
I-96 TODAY WHICH IS WHERE WE HAVE THE GREATEST ACCUMULATION. AS THE
CLIPPER PASSES BY SNOW WILL TAPER THIS AFTERNOON. THE SYNOPTIC SNOW
IS GETTING A BOOST FROM THE WESTERLY WIND OFF THE LAKE.
WE MAY SEE A 6 OR 8 HR BREAK FROM SNOW BEFORE THE NEXT CLIPPER
ARRIVES LATE TONIGHT. THE CLIPPER IS PROGD MOVE OVER THE CWA TUESDAY
RESULTING IN A 1-3/2-4 INCH TYPE EVENT. THE LIGHT WINDS EXPECTED
TODAY SHOULD RESULT IN A LOWER IMPACT EVENT. DRY WX EXPECTED
WEDNESDAY AS ZONAL FLOW DEVELOPS IN THE WAKE OF THE CLIPPER.
.LONG TERM...(WEDNESDAY NIGHT THROUGH SUNDAY)
ISSUED AT 343 AM EST MON FEB 4 2013
ZONAL FLOW STILL LOOKS TO BE THE PREDOMINATE UPPER PATTERN TYPE
THROUGH THE LONG TERM PERIOD. MAIN FEATURES TO KEY ON ARE A
SHORTWAVE TROUGH FORECAST TO SWING THROUGH THE GREAT LAKES THURSDAY
AND ANOTHER DEEPER TROUGH CENTERED AROUND SUNDAY. 850MB ARE FORECAST
TO BE BETWEEN -8C AND +4C MUCH OF THE LONG TERM WHICH WILL TAKE LAKE
EFFECT OUT OF PLAY...WHICH WILL BE A CHANGE FROM THE CURRENT AND
RECENT PAST. TEMPERATURES THROUGH THE PERIOD WILL BE NEAR TO ABOVE
NORMAL.
AS FOR THE DETAILS...HAVE A CHANCE OF SNOW MENTIONED WEDNESDAY NIGHT
AHEAD OF A SURFACE TROUGH. HAVE TRENDED POPS TO LIKELY FOR THE BULK
OF THE CWA ON THURSDAY. MAINTAINED A POSSIBLE MIX WITH RAIN IN THE
SOUTH AS 850MB TEMPS TRY TO FLIRT WITH +2C PER THE ECMWF. THE SYSTEM
MOVES EAST THURSDAY NIGHT TAKING THE PRECIPITATION WITH IT. DRY
WEATHER IS ANTICIPATED FOR FRIDAY THROUGH SATURDAY NIGHT AS HIGH
PRESSURE SLIDES THROUGH THE REGION.
THE SUNDAY SYSTEM IS ASSOCIATED WITH UPPER SOUTHWEST FLOW IN PLACE.
THE ECMWF HAS MORE OF A SOUTHERN STREAM LOW EJECTING OUR DIRECTION.
AT THIS POINT HAVE RAIN AND SNOW MENTIONED. IT APPEARS SUNDAY MAY BE
TRENDING TOWARD A COLD RAIN. GIVEN THE TIME FRAME THOUGH...DEEP INTO
THE LONG TERM...WILL MAINTAIN A MIX AS THE ZERO C 850MB ISOTHERM IS
IN THE CWA PER BOTH THE GFS AND THE ECMWF.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z TUESDAY MORNING)
ISSUED AT 659 AM EST MON FEB 4 2013
A SWATH OF SNOW IS MOVING THROUGH SOUTHWEST LOWER MICHIGAN THIS
MORNING ASSOCIATED WITH A CLIPPER SYSTEM AND ENHANCED BY THE LAKE.
THE WORST OF THE CONDITIONS SHOULD OCCUR IN THE FIRST SEVERAL HOURS
OF THIS TAF CYCLE...12Z TO 16Z. KAZO...KGRR...KBTL AND KJXN WILL
BE THE MOST IMPACTED AS THE SYSTEM SLIDES TO THE SOUTHEAST THROUGH
THE REGION. IFR CONDITIONS WILL BE LIKELY AT THE AFOREMENTIONED
SITES THIS MORNING. AN IMPROVEMENT SHOULD OCCUR FROM WEST TO EAST
DURING THE AFTERNOON HOURS...WITH CONDITIONS LIFTING TO MVFR OR
EVEN VFR. MUCH OF TONIGHT WILL BE QUIET BEFORE THE NEXT QUICK
HITTING CLIPPER MOVES IN TUESDAY MORNING.
&&
.MARINE...
ISSUED AT 343 AM EST MON FEB 4 2013
DISCONTINUED THE SCA AS WINDS AND WAVES ARE LIKELY BELOW CRITERIA.
&&
.HYDROLOGY...
ISSUED AT 343 AM EST MON FEB 4 2013
WARMER WX IS EXPECTED TOWARD THE END OF THE WEEK. THIS MAY
EXACERBATE THE ICE JAM POTENTIAL.
&&
.GRR WATCHES/WARNINGS/ADVISORIES...
MI...WINTER WEATHER ADVISORY UNTIL 1 PM EST THIS AFTERNOON FOR MIZ073-
074.
LAKE EFFECT SNOW ADVISORY UNTIL 1 PM EST THIS AFTERNOON FOR
MIZ056-064-071-072.
LM...NONE.
&&
$$
UPDATE...WDM
SYNOPSIS...93
SHORT TERM...93
LONG TERM...DUKE
AVIATION...DUKE
HYDROLOGY...93
MARINE...93
AREA FORECAST DISCUSSION
NWS HASTINGS NE
408 PM CST MON FEB 4 2013
.SHORT TERM...TONIGHT AND TUESDAY.
WE REMAIN IN NORTHWEST FLOW ALOFT FOR THE SHORT TERM. A SURFACE COLD
FRONT THAT PASSED TO THE SOUTHWEST EDGE OF THE CWA TODAY HAS STALLED
AND BEGUN TO MOVE BACK TO THE EAST. EARLIER STRATUS BEHIND THE COLD
FRONT IS CONTINUING TO ERODE...WITH MAINLY THE EASTERN CWA THE ONLY
AREA LEFT WITH APPRECIABLE STRATUS.
MODELS HAVE NOT BEEN HANDLING THE STRATUS WELL AND THE ONLY MODEL TO
LATCH ON TO IT WELL THIS MORNING WAS THE HRRR. THE STRATUS IS
BURNING OFF ON THE WESTERN EDGE FASTER THAN THE HRRR INDICATES.
ALSO...THE HRRR INDICATES A WESTWARD PUSH THIS EVENING BEFORE
SCOURING OUT FOR GOOD AS THE WARM FRONT/TROUGH MOVES EAST. SINCE THE
HRRR IS LOSING ITS GRIP ON THE SITUATION...I AM BANKING ON THE
CONTINUED EASTWARD PROGRESSION OF THE WESTERN EDGE OF THE STRATUS.
MODELS DO NOT INDICATE ANY REDUCED VISIBILITY ALONG THE WESTERN EDGE
OF THE STRATUS TONIGHT...EXCEPT THE HRRR...BUT THE HRRR ALSO
INDICATED REDUCED VISIBILITY THIS MORNING ALONG THE WESTERN EDGE OF
THE STRATUS AND THIS DID NOT COME TO FRUITION...SO I AM DISCARDING
THIS SOLUTION...AS WIND WILL BECOME WEST AND INCREASE IN STRENGTH
SOMEWHAT AS WELL.
NUDGED TEMPERATURES UP A BIT FOR TONIGHT WITH A SLIGHT INCREASE TO
WIND SPEED BEHIND THE WARM FRONT.
STILL BANKING ON A WARMER DAY WITH INCREASED 850 MB TEMPERATURES FOR
TUESDAY...WITH PLENTY OF SUN. WIND GUSTS COULD INCREASE A BIT FROM
INCREASED LAPSE RATES...BUT NOTHING THAT WOULD BE CONSIDERED
PARTICULARLY OUT OF THE ORDINARY FOR CENTRAL NEBRASKA.
.LONG TERM...TUESDAY EVENING THROUGH NEXT MONDAY. CERTAINLY THE
MOST INTRIGUING ASPECT OF THIS 6-DAY PERIOD IS THE POTENTIALLY/
REPEAT POTENTIALLY/ IMPACTFUL SYSTEM IN THE SATURDAY-SUNDAY NIGHT
TIME FRAME...AND WHETHER IT RESULTS IN ACCUMULATING SNOW AND/OR
EVEN SOME THUNDERSTORMS. HOWEVER...GIVEN THE CONSIDERABLE
UNCERTAINTY AT THIS DAY 5-6 RANGE...WILL NOT GET TOO CARRIED AWAY
AT THIS TIME. IN THE NEARER PERIODS...WILL HAVE TO WATCH FAR
SOUTHEAST COUNTIES FOR A POSSIBLE GLANCING BLOW OF SHOWERS/WEAK
THUNDERSTORMS WEDNESDAY NIGHT. OTHERWISE...AT LEAST FOR THE
WEDNESDAY-SATURDAY TIME FRAME...CONFIDENCE IS FAIRLY HIGH IN A
MILD TEMPERATURE REGIME WITH HIGHS GENERALLY AVERAGING UPPER 40S-
MID 50S.
STARTING OFF TUESDAY NIGHT...SHOULD BE BE A QUIET PERIOD. 12Z
MODELS SUCH AS THE NAM/GFS/ECMWF ARE IN GOOD AGREEMENT DEPICTING
QUASI-ZONAL FLOW ALOFT/WEAK SHORTWAVE RIDGING. AT THE
SURFACE...INITIALLY LIGHT/VARIABLE BREEZES WILL GRADUALLY BECOME
STEADIER AND FROM THE SOUTH...INCREASING TO AT LEAST 10-15 MPH IN
MANY AREAS AFTER MIDNIGHT AS A SURFACE RIDGE MIGRATES EAST AND A
LOW LEVEL JET DEVELOPING OVERHEAD PROVIDES A BIT OF MIXING. THIS
SETUP SHOULD KEEP TEMPS FROM DROPPING VERY FAR...AND MADE LITTLE
CHANGE TO PREVIOUS FORECAST WITH MID-UPPER 20S ALL AREAS. BOTH THE
SREF/NAM VISIBILITY PRODUCTS HINT AT SOME FOG POTENTIAL NEAR THE
EASTERN EDGE OF THE CWA DURING THE NIGHT...BUT WILL LEAVE OUT OF
THE FORECAST AS BELIEVE THE INCREASING BREEZES SHOULD KEEP ANY
FOG FROM AMOUNTING TO MUCH...EVEN IF IT WOULD TRY FORMING.
WEDNESDAY/WEDNESDAY NIGHT...THE PICTURE ALOFT INVOLVES THE CENTRAL
PLAINS REMAINING UNDER QUASI-ZONAL FLOW...AS A PROGRESSIVE...SLOWLY
AMPLIFYING SHORTWAVE TROUGH DRIFTS OUT OF THE NORTHERN ROCKIES
TOWARD THE NORTHERN NEB/IA REGION. AHEAD OF THIS WAVE...A
MILD...DRY AND SOMEWHAT BREEZY DAY IS ANTICIPATED...AS SUSTAINED
SOUTHWEST WINDS 15-20 MPH WITH HIGHER GUSTS PICK UP AHEAD OF AN
ADVANCING SURFACE TROUGH. THESE WIND SPEEDS ARE ROUGHLY 5 MPH
HIGHER THAN PREVIOUS FORECAST. GIVEN THIS GOOD MIXING REGIME AND
SKIES AVERAGING NO WORSE THAN PARTLY CLOUDY...LOOKING AT A
SEASONABLY WARM DAY AND PER SUGGESTION OF VARIOUS MODELS HAVE
RAISED HIGHS 2-3 DEGREES MOST AREAS...PUTTING MOST PLACES
GENERALLY 55-59. PER THE 18Z NAM...SOME WESTERN AREAS COULD EVEN
TOP 60...BUT KEPT THE VAST MAJORITY OF THE AREA BELOW 60 FOR NOW.
BY WED EVENING...THE MAIN SHORTWAVE AXIS ALOFT WILL ENTER THE
LOCAL AREA...WHILE IN THE LOW LEVELS EVIDENT FROM 850MB TO THE
SURFACE...A MODEST COLD FRONT WILL PASS THROUGH. AS THIS LOW LEVEL
BOUNDARY ENCOUNTERS INCREASING MOISTURE...VARIOUS MODELS ARE
CONSISTENT IN BREAKING OUT A CORRIDOR OF RAIN SHOWERS/EMBEDDED
WEAK THUNDERSTORMS ACROSS MUCH OF SOUTHERN/EASTERN KANSAS. WHILE
THE 18Z NAM/12Z GEM KEEP THIS ACTIVITY AT LEAST SLIGHTLY SOUTHEAST
OF OUR CWA...THE LATEST ECWMF/GFS RUNS AT LEAST BRUSH OUR FAR
SOUTHEAST COUNTIES AROUND BELOIT KS. CONTEMPLATED ADDING A SLIGHT
CHANCE OF SHOWERS IN THIS FAR SOUTHEAST AREA...BUT GIVEN THIS IS
STILL 5 FORECAST PERIODS AWAY WILL MAINTAIN OUR PREVIOUSLY DRY
FORECAST AND LET THE NEXT FEW SHIFTS MONITOR THE TRENDS FOR
POSSIBLE INTRODUCTION OF RAIN CHANCES.
THURSDAY/THURSDAY NIGHT...CONFIDENCE IS FAIRLY HIGH IN A DRY 24
HOURS...AS FAIRLY UNEVENTFUL QUASI-ZONAL FLOW IS PRESENT ALOFT
BEHIND THE SHORTWAVE TROUGH FROM WED NIGHT THAT DEPARTS EASTWARD
ACROSS IA DURING THE DAY...AND A MORE SIGNIFICANT SYSTEM JUST
STARTING TO ORGANIZE OVER THE WESTERN CONUS. LOW LEVEL TEMPS WILL
BE A BIT COOLER THAN WED...AND BREEZES WILL BE LIGHTER...WHICH
SHOULD RESULT IN A SLIGHTLY COOLER BUT STILL PLEASANT DAY. MADE
LITTLE CHANGE TO HIGH TEMPS...WITH LOW 50S MOST AREAS.
FRIDAY/FRIDAY NIGHT...THINGS START TO TURN MORE INTERESTING
ALOFT...AS THERE IS FAIRLY GOOD AGREEMENT AMONGST THE 12Z
ECMWF/GFS/GEM THAT A CLOSED 500MB LOW WILL DEVELOP OVER THE DESERT
SOUTHWEST AND BECOME CENTERED NEAR THE NV/AZ/UT BORDER AREA BY
SUNRISE SATURDAY MORNING. CONFIDENCE REMAIN QUITE HIGH IN A DRY
DAYTIME PERIOD AS FORCING REMAINS WELL SOUTHWEST OF THE LOCAL
AREA...WHILE AT THE SURFACE SOUTH BREEZES AVERAGE AT LEAST 15-20
MPH...WITH CURRENT FORECAST SPEEDS POSSIBLE NOT HIGH ENOUGH.
NUDGED UP HIGH TEMPS VERY SLIGHTLY...GETTING ALL BUT FAR EASTERN
COUNTIES TO AT LEAST 50 DEGREES. BY FRIDAY NIGHT...THE GFS SUGGESTS
THAT LOW LEVEL MOISTURE COULD INCREASE ENOUGH FOR POSSIBLE DRIZZLE
DEVELOPMENT...BUT WITH THIS BEING SEVERAL DAYS AWAY AND LIKELY NOT
A MEASURABLE PRECIP RISK...WILL LEAVE OUT ANY MENTION.
AS ALREADY MENTIONED...THE 36-HOUR TIME FRAME BETWEEN SATURDAY AND
SUNDAY NIGHT HOLDS PLENTY OF POTENTIAL TO BE VERY INTERESTING IN
SEVERAL POSSIBLE WAYS INCLUDING ACCUMULATING SNOW...THUNDERSTORMS
AND STRONG GRADIENT WINDS THAT COULD RESULT IN BLOWING SNOW.
HOWEVER...THERE IS STILL A WHOLE LOT TO HAMMER OUT STILL BEING 5-6
DAYS AWAY...SO FOR NOW HAVE ONLY INTRODUCED SOME STANDARD
ACCUMULATING SNOW POSSIBLE/UNCERTAINTY HIGH WORDING INTO THE
HAZARDOUS WEATHER OUTLOOK...AND HAVE REFRAINED FROM INTRODUCING
THUNDERSTORMS YET. IN SHORT...THE 12Z ECMWF/GEM ARE IN PRETTY GOOD
AGREEMENT MAINTAINING THIS SYSTEM AS A COMPACT...POWERFUL CLOSED
LOW THAT COULD HAVE SOME LOCAL IMPACTS...WHILE THE GFS DEPICTS A
MUCH MORE ELONGATED/LESS-FOCUSED UPPER SYSTEM WITH AT MOST ONLY A
MINOR/NUISANCE WINTRY SIDE. HAVE CAPPED POPS AT 50 PERCENT RANGE
FOR NOW...AS ITS STILL TOO EARLY TO SAY ANYTHING IS 60+ PERCENT
LIKELY AT ANY GIVEN SPOT. FOCUSING ON WHAT CONFIDENCE IS
RELATIVELY HIGH IN...ANY PRECIP THAT BREAKS OUT DAYTIME SATURDAY
SHOULD STAY IN LIQUID/SHOWERY FORM. THEN SATURDAY NIGHT...THE
ECWMF/GEM SOLUTIONS AGREE ON A FAIRLY VERTICALLY STACKED...STRONG
LOW PRESSURE SYSTEM CENTERED ALONG THE KS/CO BORDER BY SUNRISE
SUNDAY MORNING...ALTHOUGH THE ECMWF KEEPS WARMER AIR ALOFT IN
PLACE THROUGH THE NIGHT INSTEAD OF CHANGING OVER TO SNOW IN
NORTHWEST COUNTIES. AS A RESULT...HAVE MOVED THE RAIN/SNOW
TRANSITION LINE FARTHER NORTHWEST COMPARED TO PREVIOUS FORECAST.
THEN FOR SUNDAY/SUNDAY NIGHT...TH LATEST ECWMF SOLUTION TAKES THE
TRACK OF THE MID LEVEL CLOSED LOW DIRECTLY OVER THE HEART OF THE
CWA...WHICH WOULD IN THEORY FOCUS THE BEST ACCUMULATING SNOW
POTENTIAL ACROSS OUR NORTHWEST 1/2...AND MAYBE KEEP SHOWERS/STORMS
GOING IN SOUTHEAST AREAS DURING THE DAY BEFORE COLDER AIR FILTERS
IN DURING THE EVENING. PLENTY OF CHANGES ARE LIKELY IN THE DETAILS
OVER THE COMING DAYS...AND WANT TO EMPHASIZE THAT ITS STILL TOO
EARLY TO GET OVERLY CONCERNED.
GETTING BEYOND THIS POTENTIAL WEATHER-MAKER INTO MONDAY...EVEN THE
SLOWER ECMWF SOLUTION PULLS ALL PRECIP RISK AT LEAST SLIGHTLY EAST
OF THE CWA...SO WILL ADVERTISE A DRY DAY. CONFIDENCE IN HIGH TEMPS
IS QUITE LOW DEPENDING ON HOW THE WEEKEND SHAKES OUT...SO SIMPLY
WENT WITH ALLBLEND MODEL SOLUTION OF MID 30S MOST NEB ZONES...AND
NEAR 40 IN KS.
&&
.PREV DISCUSSION... /ISSUED 1200 PM CST MON FEB 4 2013/
AVIATION...18Z KGRI TAF. STRATUS WILL BE THE MOST DIFFICULT
COMPONENT TO DEAL WITH. MVFR STRATUS HAS SPREAD INTO THE AREA
BEHIND A COLD FRONT MOVING IN FROM THE NORTHEAST...BUT THE EDGE HAS
STALLED ABOUT 30 MILES WEST OF THE TERMINAL. MODELS ARE NOT
HANDLING THE EDGE OF THE STRATUS WELL...EXCEPT FOR THE HRRR MODEL
WHICH IS HANDLING THE INITIALIZATION OF THE STRATUS WELL. THIS
MODEL KEEPS US SOCKED IN THE STRATUS ALL DAY...AND WITH A SURGE
BACK TO THE WEST PREDICTED...THE STRATUS COULD HOLD FIRM WELL INTO
THE NIGHT. SOME BRIEF FOG COULD BE POSSIBLE ON THE WESTERN EDGE OF
THE STRATUS BEFORE THE WIND STARTS PICKING FROM THE WEST...BUT
CHANCES LOOK UNLIKELY AT THIS TIME. CONFIDENCE WITH SKY COVER
BECOME LOW BY THIS EVENING INTO THE OVERNIGHT.
&&
.GID WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
KS...NONE.
&&
$$
SHORT TERM/AVIATION...HEINLEIN
LONG TERM...PFANNKUCH
AREA FORECAST DISCUSSION
NWS HASTINGS NE
1200 PM CST MON FEB 4 2013
.AVIATION...18Z KGRI TAF. STRATUS WILL BE THE MOST DIFFICULT
COMPONENT TO DEAL WITH. MVFR STRATUS HAS SPREAD INTO THE AREA
BEHIND A COLD FRONT MOVING IN FROM THE NORTHEAST...BUT THE EDGE HAS
STALLED ABOUT 30 MILES WEST OF THE TERMINAL. MODELS ARE NOT
HANDLING THE EDGE OF THE STRATUS WELL...EXCEPT FOR THE HRRR MODEL
WHICH IS HANDLING THE INITIALIZATION OF THE STRATUS WELL. THIS
MODEL KEEPS US SOCKED IN THE STRATUS ALL DAY...AND WITH A SURGE
BACK TO THE WEST PREDICTED...THE STRATUS COULD HOLD FIRM WELL INTO
THE NIGHT. SOME BRIEF FOG COULD BE POSSIBLE ON THE WESTERN EDGE OF
THE STRATUS BEFORE THE WIND STARTS PICKING FROM THE WEST...BUT
CHANCES LOOK UNLIKELY AT THIS TIME. CONFIDENCE WITH SKY COVER
BECOME LOW BY THIS EVENING INTO THE OVERNIGHT.
&&
.PREV DISCUSSION... /ISSUED 1131 AM CST MON FEB 4 2013/
DISCUSSION...UPDATING THE FORECAST FOR TODAY INTO TONIGHT DUE TO
THE SIGNIFICANT AMOUNT OF STRATUS BEHIND A COLD FRONT MOVING IN
FROM THE NORTHEAST TODAY. MODELS ARE GENERALLY NOT PICKING UP ON
THIS WELL...EXCEPT FOR THE HRRR. THEREFORE...FOLLOWING MORE
CLOSELY TO THE HRRR FOR SKY COVER TODAY AND TONIGHT...WITH THE
WESTERN/SOUTHWESTERN EDGE OF THE CWA STAYING IN THE SUN FOR THE
MOST PART. THIS WILL LEAD TO A WIDE RANGE OF TEMPERATURES TODAY.
UNDER THE STRATUS...IT APPEARS THAT LOWER TO MID 30S WILL BE THE
WAY TO GO...WITH LOWER TO MID 50S FOR HIGHS IN THE FAR WEST WHERE
THE SUN WILL PREVAIL. THIS IS A DRAMATIC SHIFT COOLER WHERE THE
STRATUS IS NOW FORECAST COMPARED TO THE FORECAST EARLIER THIS
MORNING...BY ABOUT 10 TO 15 DEGREES.
PREV DISCUSSION... /ISSUED 334 AM CST MON FEB 4 2013/
SHORT TERM...TODAY THROUGH 12Z THURSDAY. MAIN FORECAST CONCERN WILL
BE TEMPERATURES.
SURFACE ANALYSIS SHOWS A LOW PRESSURE SYSTEM AND COLD FRONT MOVING
THROUGH THE AREA EARLY THIS MORNING. IT WILL BE THROUGH THE FORECAST
AREA BY MORNING. OBSERVATIONS SHOW THAT THERE IS NOT MUCH COLD AIR
BEHIND THE FRONT.
A COOL SURFACE HIGH PRESSURE SYSTEM SETTLES INTO THE AREA TODAY.
TEMPERATURES WILL BE COOLER THAN YESTERDAY. LOWER CLOUDS FROM THE
DAKOTAS SHOULD BREAK UP A LITTLE AS THEY MOVE TO THE SOUTH BUT
EXPECT SOME TO MOVE INTO THE NORTH AND ESPECIALLY INTO THE NORTHEAST
TODAY. THIS WILL KEEP THAT AREA A BIT COOLER. EVEN THOUGH IT IS
COOLER...TEMPERATURES WILL BE ABOVE NORMAL. THE COOL SURFACE HIGH
PRESSURE SYSTEM MOVES TO THE EAST TONIGHT AND WINDS TURN TOWARD THE
WEST. THERE IS NOT MUCH WARM ADVECTION BUT THE DOWN SLOPING ASPECT
OF THE WINDS WILL KEEP TEMPERATURES FROM FALLING OFF TOO MUCH
TONIGHT.
ON TUESDAY THERE WILL BE MORE SUNSHINE AND A LITTLE WARM ADVECTION.
TEMPERATURES WILL WARM BACK UP A LITTLE. THE WARMING TREND CONTINUES
INTO TUESDAY NIGHT WITH TEMPERATURES A LITTLE WARMER. AN UPPER LEVEL
WAVE MOVES INTO THE AREA ON WEDNESDAY AND A COLD FRONT MOVES THROUGH
THE FORECAST AREA DURING THE AFTERNOON. SINCE MOST OF THE AREA WILL
HAVE SOME WARM ADVECTION MOST OF THE DAY EXPECT TEMPERATURES TO BE A
BIT WARMER ON WEDNESDAY. AFTER THE FRONT MOVES THROUGH THE AREA THE
UPPER WAVE GETS SOME SHOWERS TO DEVELOP ALONG THE FRONT. BY THE TIME
THESE GET STARTED...THE FRONT SHOULD BE FAR ENOUGH TO THE SOUTHEAST
THAT IT WOULD BE OUT OF THE AREA. HAVE CONTINUED THE DRY FORECAST
FOR WEDNESDAY NIGHT.
LONG TERM...THURSDAY THROUGH SUNDAY...CHANGES APPEAR TO BE ON THE
HORIZON OVER THE UPCOMING WEEKEND AS A POTENT UPPER LEVEL LOW
PRESSURE SYSTEM BEGINS TO SPREAD ITS INFLUENCE ACROSS THE LOCAL AREA
BY SATURDAY.
SHORT WAVE RIDGING WILL BE IN PLACE ACROSS THE PLAINS TO START THE
EXTENDED PERIODS AS AN UPPER LEVEL LOW PROGRESSES DOWN THE WEST
COAST AND ANOTHER UPPER LEVEL DISTURBANCE WORKS ITS WAY ACROSS THE
GREAT LAKES REGION. AS A RESULT...DRY CONDITIONS AND UNSEASONABLY
WARM TEMPERATURES ARE EXPECTED FOR THE END OF THE WORK WEEK...WITH
AFTERNOON TEMPERATURES BOTH THURSDAY AND FRIDAY EXPECTED TO CLIMB 10
OR SO DEGREES ABOVE SEASONAL NORMS. THEREAFTER...THINGS BEGIN TO GET
MUCH MORE INTERESTING AS MODEL CONSENSUS CONTINUES TO INDICATE THERE
WILL BE A POTENT UPPER LEVEL LOW PRESSURE SYSTEM ACROSS THE DESERT
SOUTHWEST. WITH MANY OF THE GFS ENSEMBLE MEMBERS AS WELL AS EC
CUTTING OFF THIS LOW AT 500 MB AND SLOWING ITS EJECTION INTO THE
PLAINS...WENT AHEAD AND DISCOUNTED THE OPERATIONAL GFS A BIT...AND
KEPT THE FRIDAY NIGHT PERIOD DRY.
WHILE MOISTURE IS EXPECTED TO BEGIN SPILLING INTO THE PLAINS ON
SATURDAY...CONFIDENCE OF PRECIPITATION BEGINNING DURING THE DAYTIME
HOURS SATURDAY IS A BIT SHAKY...AND PREFER EC SOLUTION WHICH KEEPS
AREA DRY FOR THE DAYTIME HOURS...BUT KEPT WITH THE ALL BLEND CHANCE
POPS DURING THE DAY FOR NOW AS THERE IS ENOUGH UNCERTAINTY IN TIMING
TO JUSTIFY THIS. IF PRECIP DOES DEVELOP DURING THE DAY ON
SATURDAY...EXPECT IT TO FALL AS ALL RAIN IN LINE WITH MODELED
SOUNDINGS...WITH ANY CHANCE OF THUNDERSTORMS REMAINING WELL TO THE
SOUTH OF THE AREA AS CAPE IS VIRTUALLY NON EXISTENT ACROSS THE LOCAL
AREA.
SATURDAY NIGHT INTO SUNDAY...THINGS GET MORE INTERESTING DEPENDING
ON WHICH MODEL SOLUTION YOU TRUST...BUT TEMPS ALOFT WILL BEGIN TO
COOL AND EXPECT A TRANSITION OF RAIN SHOWERS TO LIGHT SNOW DURING THE
OVERNIGHT HOURS...WITH ACCUMULATING SNOWFALL A POSSIBILITY NEXT
SUNDAY. HOWEVER...AS MENTIONED IN PREVIOUS DISCUSSION...MUCH
UNCERTAINTY REMAINS IN ACTUAL TIMING AND PRECIP TOTALS THIS FAR
OUT...BUT ALL SIGNS DO AT LEAST POINT TO A CHANGE IN THE GENERAL
WEATHER PATTERN BY NEXT WEEKEND.
&&
.GID WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
KS...NONE.
&&
$$
AVIATION/DISCUSSION (UPDATE)...HEINLEIN
AREA FORECAST DISCUSSION
NWS HASTINGS NE
1131 AM CST MON FEB 4 2013
.DISCUSSION...UPDATING THE FORECAST FOR TODAY INTO TONIGHT DUE TO
THE SIGNIFICANT AMOUNT OF STRATUS BEHIND A COLD FRONT MOVING IN
FROM THE NORTHEAST TODAY. MODELS ARE GENERALLY NOT PICKING UP ON
THIS WELL...EXCEPT FOR THE HRRR. THEREFORE...FOLLOWING MORE
CLOSELY TO THE HRRR FOR SKY COVER TODAY AND TONIGHT...WITH THE
WESTERN/SOUTHWESTERN EDGE OF THE CWA STAYING IN THE SUN FOR THE
MOST PART. THIS WILL LEAD TO A WIDE RANGE OF TEMPERATURES TODAY.
UNDER THE STRATUS...IT APPEARS THAT LOWER TO MID 30S WILL BE THE
WAY TO GO...WITH LOWER TO MID 50S FOR HIGHS IN THE FAR WEST WHERE
THE SUN WILL PREVAIL. THIS IS A DRAMATIC SHIFT COOLER WHERE THE
STRATUS IS NOW FORECAST COMPARED TO THE FORECAST EARLIER THIS
MORNING...BY ABOUT 10 TO 15 DEGREES.
&&
.PREV DISCUSSION... /ISSUED 542 AM CST MON FEB 4 2013/
AVIATION...12Z KGRI TAF...AN EXPANSIVE DECK OF MVFR STRATUS
ASSOCIATED WITH AN ARCTIC FRONT TO THE NORTHEAST IS RAPIDLY
APPROACHING THE TERMINAL THIS MORNING. WHILE LATEST GUIDANCE DOES
NOT INDICATE THIS STATUS DECK WILL REACH KGRI...CANNOT IGNORE
SATELLITE IMAGERY WHICH HAS THE STRATUS PROJECTED TO REACH KGRI
BETWEEN 12Z AND 13Z. THIS STRATUS WILL SLOWLY PULL EAST WITH THE
ARCTIC FRONT BY EARLY AFTERNOON...AND HAVE PREVAILING VFR
CONDITIONS RETURNING AFT 19Z. WINDS TODAY WILL BE OUT OF THE NORTH
NEAR 10 KTS...BECOMING LIGHT AND VARIABLE BY AFTERNOON...BEFORE
SWITCHING SOUTHERLY OVERNIGHT IN RETURN FLOW AROUND SURFACE HIGH
SLIDING BY TO THE EAST.
PREV DISCUSSION... /ISSUED 334 AM CST MON FEB 4 2013/
SHORT TERM...TODAY THROUGH 12Z THURSDAY. MAIN FORECAST CONCERN WILL
BE TEMPERATURES.
SURFACE ANALYSIS SHOWS A LOW PRESSURE SYSTEM AND COLD FRONT MOVING
THROUGH THE AREA EARLY THIS MORNING. IT WILL BE THROUGH THE FORECAST
AREA BY MORNING. OBSERVATIONS SHOW THAT THERE IS NOT MUCH COLD AIR
BEHIND THE FRONT.
A COOL SURFACE HIGH PRESSURE SYSTEM SETTLES INTO THE AREA TODAY.
TEMPERATURES WILL BE COOLER THAN YESTERDAY. LOWER CLOUDS FROM THE
DAKOTAS SHOULD BREAK UP A LITTLE AS THEY MOVE TO THE SOUTH BUT
EXPECT SOME TO MOVE INTO THE NORTH AND ESPECIALLY INTO THE NORTHEAST
TODAY. THIS WILL KEEP THAT AREA A BIT COOLER. EVEN THOUGH IT IS
COOLER...TEMPERATURES WILL BE ABOVE NORMAL. THE COOL SURFACE HIGH
PRESSURE SYSTEM MOVES TO THE EAST TONIGHT AND WINDS TURN TOWARD THE
WEST. THERE IS NOT MUCH WARM ADVECTION BUT THE DOWN SLOPING ASPECT
OF THE WINDS WILL KEEP TEMPERATURES FROM FALLING OFF TOO MUCH
TONIGHT.
ON TUESDAY THERE WILL BE MORE SUNSHINE AND A LITTLE WARM ADVECTION.
TEMPERATURES WILL WARM BACK UP A LITTLE. THE WARMING TREND CONTINUES
INTO TUESDAY NIGHT WITH TEMPERATURES A LITTLE WARMER. AN UPPER LEVEL
WAVE MOVES INTO THE AREA ON WEDNESDAY AND A COLD FRONT MOVES THROUGH
THE FORECAST AREA DURING THE AFTERNOON. SINCE MOST OF THE AREA WILL
HAVE SOME WARM ADVECTION MOST OF THE DAY EXPECT TEMPERATURES TO BE A
BIT WARMER ON WEDNESDAY. AFTER THE FRONT MOVES THROUGH THE AREA THE
UPPER WAVE GETS SOME SHOWERS TO DEVELOP ALONG THE FRONT. BY THE TIME
THESE GET STARTED...THE FRONT SHOULD BE FAR ENOUGH TO THE SOUTHEAST
THAT IT WOULD BE OUT OF THE AREA. HAVE CONTINUED THE DRY FORECAST
FOR WEDNESDAY NIGHT.
LONG TERM...THURSDAY THROUGH SUNDAY...CHANGES APPEAR TO BE ON THE
HORIZON OVER THE UPCOMING WEEKEND AS A POTENT UPPER LEVEL LOW
PRESSURE SYSTEM BEGINS TO SPREAD ITS INFLUENCE ACROSS THE LOCAL AREA
BY SATURDAY.
SHORT WAVE RIDGING WILL BE IN PLACE ACROSS THE PLAINS TO START THE
EXTENDED PERIODS AS AN UPPER LEVEL LOW PROGRESSES DOWN THE WEST
COAST AND ANOTHER UPPER LEVEL DISTURBANCE WORKS ITS WAY ACROSS THE
GREAT LAKES REGION. AS A RESULT...DRY CONDITIONS AND UNSEASONABLY
WARM TEMPERATURES ARE EXPECTED FOR THE END OF THE WORK WEEK...WITH
AFTERNOON TEMPERATURES BOTH THURSDAY AND FRIDAY EXPECTED TO CLIMB 10
OR SO DEGREES ABOVE SEASONAL NORMS. THEREAFTER...THINGS BEGIN TO GET
MUCH MORE INTERESTING AS MODEL CONSENSUS CONTINUES TO INDICATE THERE
WILL BE A POTENT UPPER LEVEL LOW PRESSURE SYSTEM ACROSS THE DESERT
SOUTHWEST. WITH MANY OF THE GFS ENSEMBLE MEMBERS AS WELL AS EC
CUTTING OFF THIS LOW AT 500 MB AND SLOWING ITS EJECTION INTO THE
PLAINS...WENT AHEAD AND DISCOUNTED THE OPERATIONAL GFS A BIT...AND
KEPT THE FRIDAY NIGHT PERIOD DRY.
WHILE MOISTURE IS EXPECTED TO BEGIN SPILLING INTO THE PLAINS ON
SATURDAY...CONFIDENCE OF PRECIPITATION BEGINNING DURING THE DAYTIME
HOURS SATURDAY IS A BIT SHAKY...AND PREFER EC SOLUTION WHICH KEEPS
AREA DRY FOR THE DAYTIME HOURS...BUT KEPT WITH THE ALL BLEND CHANCE
POPS DURING THE DAY FOR NOW AS THERE IS ENOUGH UNCERTAINTY IN TIMING
TO JUSTIFY THIS. IF PRECIP DOES DEVELOP DURING THE DAY ON
SATURDAY...EXPECT IT TO FALL AS ALL RAIN IN LINE WITH MODELED
SOUNDINGS...WITH ANY CHANCE OF THUNDERSTORMS REMAINING WELL TO THE
SOUTH OF THE AREA AS CAPE IS VIRTUALLY NON EXISTENT ACROSS THE LOCAL
AREA.
SATURDAY NIGHT INTO SUNDAY...THINGS GET MORE INTERESTING DEPENDING
ON WHICH MODEL SOLUTION YOU TRUST...BUT TEMPS ALOFT WILL BEGIN TO
COOL AND EXPECT A TRANSITION OF RAIN SHOWERS TO LIGHT SNOW DURING THE
OVERNIGHT HOURS...WITH ACCUMULATING SNOWFALL A POSSIBILITY NEXT
SUNDAY. HOWEVER...AS MENTIONED IN PREVIOUS DISCUSSION...MUCH
UNCERTAINTY REMAINS IN ACTUAL TIMING AND PRECIP TOTALS THIS FAR
OUT...BUT ALL SIGNS DO AT LEAST POINT TO A CHANGE IN THE GENERAL
WEATHER PATTERN BY NEXT WEEKEND.
&&
.GID WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
KS...NONE.
&&
$$
DISCUSSION (UPDATE)...HEINLEIN