Forecast Discussions mentioning any of
"HRRR" "RAP" "RR" "RUC13" "RUC" received at GSD on 02/03/13
AREA FORECAST DISCUSSION
NWS ALBANY NY
102 AM EST FRI FEB 1 2013
.SYNOPSIS...
AS A CANADIAN AIR MASS MOVES INTO THE REGION...TEMPERATURES WILL BE
MUCH COLDER TONIGHT WITH A DIMINISHING WIND. LAKE EFFECT SNOW
SHOWERS WILL CONTINUE TO AFFECT THE WESTERN ADIRONDACKS AND MOHAWK
VALLEY OVERNIGHT. LAKE EFFECT SNOW WILL SHIFT SOUTH AND WEST OF THE
REGION TOMORROW...WITH COLD TEMPERATURES AND BREEZY CONDITIONS.
SEASONABLY CHILLY TEMPERATURES WILL CONTINUE TO BE IN PLACE OVER THE
WEEKEND.
&&
.NEAR TERM /UNTIL 6 AM FRIDAY MORNING/...
AS OF 1245 AM...LAKE ERIE AND LAKE ONTARIO SNOW BANDS ARE SLOWLY
MIGRATING SOUTHWARD...ESPECIALLY THE LAKE ERIE BAND. LAKE ERIE SNOW
BAND INTO CURRENTLY RUNS THROUGH SCHOHARIE AND ALBANY COUNTIES AND
TAPERS OFF FURTHER TO THE EAST. THE LAKE ONTARIO BAND GENERALLY RUNS
FROM HERKIMER LANDING TO NEAR LAKE GEORGE VILLAGE...AND THEN TAPERS
OFF FURTHER TO THE EAST. HAVE ADJUSTED POP/WX/SNOW AMOUNT GRIDS TO
REFLECT CURRENT POSITION AND FUTURE MOVEMENT OF THESE SNOW BANDS. NO
CHANGE TO THE LAKE EFFECT SNOW HEADLINES CURRENTLY IN EFFECT.
.PREVIOUS DISCUSSION...
AS OF 915 PM...MAIN LAKE EFFECT BAND NOW BECOMING MORE
DISORGANIZED AND SHIFTING SOUTHWARD THROUGH HERKIMER AND HAMILTON
COUNTIES WITH SNOWFALL AMOUNTS GENERALLY IN THE 4-6 RANGE REPORTED
BY LOCAL SPOTTERS. ELSEWHERE...A BAND OF SNOW SHOWERS...AIDED BY
MOHAWK VALLEY CONVERGENCE AND LAKE-ENHANCED MOISTURE HAD REACHED
THE CAPITAL DISTRICT. THIS BAND WILL CONTINUE TO IMPACT THE
CAPITAL REGION THROUGH THE NEXT COUPLE OF HOURS...WITH GENERALLY A
DUSTING TO A FEW TENTHS OF ACCUMULATION.
WINDS ARE STARTING TO DIMINISH SLIGHTLY AS THE PRESSURE GRADIENT
BEGINS TO RELAX. WINDS WILL STILL REMAIN 10-15KTS SUSTAINED WITH
SOME GUSTS OVER 25KTS POSSIBLE UNTIL 3Z. CURRENT FORECAST LOOKS TO
BE SPOT ON. ONLY MINOR CHANGES TO CURRENT TEMPS, DEWPOINTS AND
WIND.
A BAND OF LAKE EFFECT SNOW IS CURRENTLY ONGOING ACROSS THE
WESTERN ADIRONDACKS. THE LOCAL HIRES WRF MODEL...AS WELL AS THE
NAM12 AND 3KM HRRR MODEL...SHOWS THIS BAND TO SHIFT SOUTHWARD
DURING THE OVERNIGHT HOURS. WITH THIS BAND HAVING AN EXCELLENT
MULTI-LAKE CONNECTION ALL THE WAY BACK TO THE WESTERN GREAT LAKES
AND STRONG LOW LEVEL SPEED SHEAR...LOCAL CSTAR RESEARCH WOULD
SUGGEST THAT THIS BAND REACHES WELL INTO OUR AREA. AS A
RESULT...HAVE ALSO INCLUDED A LAKE EFFECT SNOW ADVISORY FOR
HAMILTON COUNTY...IN ADDITION TO THE WSW ALREADY IN EFFECT FOR NRN
HERKIMER. SNOW TOTALS LOOK TO REACH 4-8 INCHES IN NRN HERKIMER AND
3-6 INCHES ACROSS WESTERN HAMILTON COUNTY.
AS THE BAND SHIFTS SOUTH FOR LATE TONIGHT...IT SHOULD MOVE
QUICKLY. WHILE A QUICK FEW INCHES OF ACCUMULATION IS POSSIBLE
ACROSS THE MOHAWK VALLEY...IT SHOULD MOVE QUICK ENOUGH SOUTHWARD TO
PREVENT ANY MODERATE ACCUMULATION OF SNOW. AS A RESULT...WE WILL
NOT ISSUE ANY LAKE EFFECT ADVISORIES FOR THE MOHAWK VALLEY
AREA...BUT WILL CONTINUE TO MENTION IN OUR HWO STATEMENT.
ELSEWHERE...SOME UPSLOPE SNOW SHOWERS ARE POSSIBLE FOR THE HIGH
TERRAIN OF WESTERN NEW ENGLAND WITH SOME MINOR SNOW ACCUMULATION
POSSIBLE. THE REMAINDER OF THE REGION LOOKS TO BE DRY...ALTHOUGH
AS THE LAKE BAND SHIFTS SOUTHWARD...THE INLAND EXTENT MAY ALLOW
FOR SOME FLAKES TO REACH THE CAPITAL REGION FOR 08Z-12Z. NOT
EXPECTING MUCH ACCUMULATION...BUT IT/S POSSIBLE FOR A COATING OF
SNOW IN THE ALBANY/SCHENECTADY/TROY AREA BY LATE IN THE NIGHT
TOWARDS DAYBREAK.
MIN TEMPS WILL BE MUCH COOLER THAN LAST NIGHT. MINS WILL RANGE
FROM THE SINGLE DIGITS IN THE ADKS TO THE LOW TO MID 20S IN THE
MID HUDSON VALLEY.
&&
.SHORT TERM /6 AM FRIDAY MORNING THROUGH SATURDAY NIGHT/...
MAINLY DRY AND SEASONABLY COOL WEATHER IS EXPECTED THROUGH THE
SHORT TERM PERIOD.
THE LAKE BAND WILL SHIFT SOUTH AND WEST OF THE CWA BY FRIDAY
MORNING...MAINLY ENDING THE THREAT FOR LAKE EFFECT IN OUR AREA.
THE EXCEPTION MAY BE A FEW HOURS OF SNOW FOR WESTERN SCHOHARIE
COUNTY WITH SOME LIGHT SNOW ACCUMULATION EARLY FRIDAY MORNING
BEFORE THE BAND SHIFTS AWAY FROM THE AREA. MAX TEMPS WILL BE
NOTICEABLY COOLER...WITH TEENS AND 20S ACROSS THE AREA. IN
ADDITION...DAYTIME MIXING WILL ALLOW FOR SOME GUSTY WINDS...SO IT
WILL FEEL EVEN COLDER...WITH SOME GUSTS OF 15-30 MPH POSSIBLE.
WE WILL CONTINUE TO MENTION LOW CHC OR SLIGHT CHC POPS FOR FAR
WESTERN AREAS FOR FRIDAY AFTERNOON...IN CASE UPSLOPE FLOW DOES
ALLOW FOR SOME LIGHT SNOW SHOWERS...BUT ANY ADDITIONAL SNOW
ACCUMULATION LOOKS LIGHT. THE HUDSON VALLEY AREA SHOULD REMAIN
MAINLY DRY.
CHILLY...BUT SEASONABLE TEMPS...ARE EXPECTED FRIDAY NIGHT WITH
TEMPS RANGING FROM A FEW DEGREES BELOW ZERO ACROSS THE ADIRONDACKS
TO THE MID TEENS IN THE HUDSON VALLEY/NW CT.
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...OTHERWISE IT LOOKS CONTINUED DRY AND
COOL. MAX TEMPS ON SATURDAY WILL MAINLY BE IN THE TEENS AND 20S.
MIN TEMPS SAT NIGHT WILL RANGE FROM THE SINGLE DIGITS UP NORTH TO
NEAR 20 SOUTH.
&&
.LONG TERM /SUNDAY THROUGH THURSDAY/...
MEAN UPPER TROUGH OVER EASTERN NORTH AMERICA THROUGH THE PERIOD...
WITH LITTLE NORTHERN STREAM IMPULSES TRACKING RAPIDLY THROUGH THE
CYCLONIC FLOW. THE TIMING OF THESE SYSTEMS IN SUCH QUICK UPPER FLOW
IS IN QUESTION BUT TIMED THE BETTER CHANCES FOR SNOW IN THE SUNDAY
TIME FRAME AND AGAIN IN THE MONDAY NIGHT TO TUESDAY TIME FRAME.
THESE SYSTEMS COULD TRACK FAR ENOUGH EAST AND SOUTH OF OUR REGION
THAT THERE COLD BE LITTLE TO NO SNOW IN MUCH OF THE FORECAST AREA...
SO INDICATING BEST CHANCES IN THE MID HUDSON VALLEY...NW CT AND THE
BERKSHIRES. ANY PRECIPITATION WOULD BE RELATIVELY LIGHT IN BOTH
EVENTS...AND SHOULD NOT REQUIRE SNOW HEADLINES SINCE THE STORMS
SHOULD BE STARVED FOR MOISTURE UNTIL THEY RAPIDLY HEAD OFFSHORE AND
WELL EAST OF OUR REGION.
OUTSIDE OF THESE POTENTIAL 2 SMALL EVENTS...SOME PERSISTENT LAKE
EFFECT SNOW BANDS COULD EXTEND INTO THE SOUTHERN ADIRONDACKS...
WESTERN MOHAWK VALLEY...SCHOHARIE VALLEY AND EASTERN CATSKILLS.
SO...PERIODS OF CLOUDS THROUGH THE PERIOD WITH TEMPERATURES AROUND
NORMAL SUNDAY...A LITTLE BELOW NORMAL MONDAY THROUGH WEDNESDAY AND
BACK TO AROUND NORMAL THURSDAY.
&&
.AVIATION /06Z FRIDAY THROUGH MONDAY/...
MAINLY VFR CONDITIONS ARE EXPECTED FOR THE 24 HOUR PERIOD ENDING 06Z
SATURDAY. THE ONLY EXCEPTION WILL BE THE CHANCE FOR SOME LIGHT LAKE
EFFECT SNOW SHOWERS INTO THIS MORNING FOR MAINLY KALB/KGFL/KPSF.
DIFFICULT TO TIME DUE TO IMPENDING MOVEMENT AND EASTWARD EXTENT OF
NARROW SNOW BANDS...SO WILL NOT INCLUDE ANY MENTION OF IFR IN THE
TAFS AT THIS TIME.
OTHERWISE...BRISK CONDITIONS WILL PREVAIL WITH GENERALLY
WEST-NORTHWEST WINDS AROUND 10-20 KT WITH GUSTS OF 25-30 KT.
OUTLOOK...
FRI-MON...MAINLY VFR. CHC SUB-VFR -SHSN.
&&
.HYDROLOGY...
SNOWMELT FROM THE RECENT WARMER TEMPERATURES AND RAINFALL FROM
EARLY THIS MORNING COMBINED FOR SOME RUNOFF ACROSS THE REGION THIS
MORNING. HOWEVER...THIS WAS NOT ENOUGH TO CAUSE FLOODING ACROSS
OUR AREA. WITH TEMPERATURES COOLING BELOW FREEZING ACROSS THE
ENTIRE AREA THIS EVENING...ANY SNOWMELT SHOULD END...AND RIVERS
WILL START TO RECEDE.
BECAUSE OF THE WARM TEMPERATURES AND RAINFALL...SOME ICE BROKE UP
IN AREA RIVERS AND STREAMS. THIS CAUSED SOME MINOR FLOODING ON THE
EAST CANADA CREEK IN DOLGEVILLE AND ALONG THE HOOSIC RIVER NEAR
BUSKIRK. THE THREAT FOR ICE JAMS SHOULD DECREASE THIS EVENING
WITH THE COOLER TEMPERATURES...AND ALTHOUGH ANY ICE THAT BROKE UP
MAY BEGIN TO REFREEZE IN PLACE...LOWERING FLOWS SHOULD PREVENT ANY
FLOODING FROM OCCURRING.
THE NEXT SEVERAL DAYS WILL BE FAIRLY DRY...AND ANY LIGHT
PRECIPITATION WILL BE IN THE FORM OF SNOW. THIS SHOULD ALLOW
RIVERS AND STREAMS TO SLOWLY RECEDE INTO EARLY NEXT WEEK.
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...LAKE EFFECT SNOW ADVISORY UNTIL 6 AM EST FRIDAY FOR NYZ032-033.
MA...NONE.
VT...NONE.
&&
$$
SYNOPSIS...GJM/FRUGIS/VTK/IRL
NEAR TERM...GJM/FRUGIS/VTK
SHORT TERM...FRUGIS
LONG TERM...NAS
AVIATION...JPV
HYDROLOGY...FRUGIS
AREA FORECAST DISCUSSION
NWS CHARLESTON SC
923 PM EST SAT FEB 2 2013
.SYNOPSIS...
A COLD FRONT WILL CROSS THE REGION TONIGHT AND HIGH PRESSURE WILL
PREVAIL SUNDAY AND MONDAY. WEAK LOW PRESSURE WILL PASS JUST SOUTH
OF THE AREA TUESDAY...FOLLOWED BY HIGH PRESSURE INTO LATE WEEK.
ANOTHER COLD FRONT COULD PUSH INTO THE SOUTHEAST UNITED STATES
BEFORE STALLING LATE WEEK INTO NEXT WEEKEND.
&&
.NEAR TERM /UNTIL 6 AM SUNDAY MORNING/...
A COLD FRONT IS STEADILY APPROACHING FROM THE WEST AND IS ON
TARGET TO PUSH THROUGH THE FORECAST AREA OVERNIGHT. SHOWER ACTIVITY
MOVING ACROSS PORTIONS OF THE SOUTH CAROLINA MIDLANDS AND EAST-
CENTRAL GEORGIA IS SHOWING SIGNS OF WEAKENING/DISSIPATING AS IT
MOVES EAST AND ENCOUNTERS INCREASINGLY DRIER AIR. THE LATEST RUNS
OF THE H3R AND RAP MODELS SUPPORT KEEPING CONDITIONS DRY OVERNIGHT
WHICH LOOKS REASONABLE GIVEN CURRENT RADAR AND SATELLITE TRENDS. CAN
NOT COMPLETELY RULE OUT A FEW LIGHT SPRINKLES WELL INLAND...BUT
MEASURABLE RAINFALL IS NOT EXPECTED.
TEMPERATURES HAVE FALLEN QUICKLY THIS EVENING WITH CALM/LIGHT
WINDS AND LOW DEWPOINTS IN PLACE. IN FACT...SOME AREAS ARE ALREADY
APPROACHING FORECAST MINIMA ACROSS THE COASTAL COUNTIES. SHOULD
SEE TEMPERATURES STEADY OR EVEN RISE OVER THE NEXT FEW HOURS AS
CLOUDS INCREASE FROM THE WEST SO WILL NOT MAKE ANY CHANGES TO THE
LOW TEMPERATURE FORECAST. LOWS FROM THE MID-UPPER 30S INLAND TO
THE UPPER 30-LOWER 40S AT THE COAST LOOK FINE FOR NOW.
&&
.SHORT TERM /6 AM SUNDAY MORNING THROUGH TUESDAY/...
SUNDAY...ANY LINGERING CLOUDS EARLY WILL GIVE WAY TO SUNNY/MOSTLY
SUNNY SKIES. A TIGHT SURFACE PRESSURE GRADIENT AND A DEEPENING MIXED
LAYER WILL SUPPORT WEST WINDS GUSTING AS HIGH AS 30-35 MPH
ESPECIALLY DURING THE AFTERNOON. TEMPERATURES SHOULD TOP OUT IN THE
LOWER 60S AT MANY LOCATIONS...AND DOWNSLOPE FLOW/DEWPOINTS LOWERING
INTO THE UPPER 20S COULD SUPPORT HIGHS IN THE MID 60S AT A FEW
LOCATIONS NEAR THE COAST AND ACROSS SOUTHERN COUNTIES.
A COMBINATION OF COLD ADVECTION AND RADIATIVE COOLING AS SURFACE
WINDS BECOME NEARLY CALM TOWARD DAYBREAK WILL PUSH TEMPERATURES
INTO THE UPPER 20S TO LOWER 30S AT MANY LOCATIONS. THEN...AS HIGH
CLOUDS INCREASE AND THICKEN FROM THE WEST MONDAY TEMPERATURES SHOULD
TOP OUT A COUPLE OF DEGREES COOLER THAN THOSE OF SUNDAY
AFTERNOON...IN THE UPPER 50S TO LOWER 60S MOST LOCATIONS...AND WINDS
WILL REMAIN MUCH LIGHTER THAN THOSE OF SUNDAY.
SKIES WILL BECOME MOSTLY CLOUDY MONDAY NIGHT AS MID/HIGH LEVEL
CLOUDS DEVELOPING WITHIN AN UPSTREAM ISENTROPIC ASCENT REGIME STREAM
EAST ACROSS THE REGION. THIS SHOULD HOLD LOW TEMPERATURES 35-40F
INLAND AND MID 40S TO AROUND 50 AT THE COAST. IN FACT...OVERNIGHT
TEMPERATURES COULD BECOME UNSTEADY AND EVEN RISE A FEW DEGREES IN
SOME LOCATIONS.
THE BULK OF 02/12Z GUIDANCE SUGGESTS THAT A WEAK SHORTWAVE AND
ASSOCIATED SUBTLE FORCING FOR ASCENT/BAND OF ENHANCED MOISTURE WILL
PASS THROUGH THE REGION TUESDAY. NUDGED THE FORECAST IN THE
DIRECTION OF THE 12Z GFS WITH SLIGHT CHANCE POPS ACROSS SOUTHERN
COUNTIES...STILL LOWER POPS AND LESS COVERAGE OF POPS 15 PERCENT OR
GREATER THAN DEPICTED BY THE GFS. ANY QPF SHOULD REMAIN PALTRY...IN
MOST CASES LESS THAN ONE-TENTH OF AN INCH.
LAKE WINDS...DUE TO FREQUENT GUSTS TO AT LEAST 25 KNOTS EXPECTED
OVER LAKE MOULTRIE LATE SUNDAY MORNING/EARLY SUNDAY AFTERNOON
THROUGH LATE SUNDAY AFTERNOON/EARLY SUNDAY EVENING...ISSUED A LAKE
WIND ADVISORY FOR THE LAKE VALID 10 AM UNTIL 8 PM SUNDAY.
&&
.LONG TERM /TUESDAY NIGHT THROUGH SATURDAY/...
A RELATIVELY ZONAL FLOW WILL EXIST IN THE LONG TERM ALTHOUGH A BROAD
RIDGE COULD DEVELOP NEXT WEEKEND. A SHORTWAVE DISTURBANCE WILL MOVE
THROUGH ON THURSDAY...PUSHING A COLD FRONT SLOWLY SOUTHEAST THROUGH
THE AREA. THIS FRONT MAY STALL ACROSS THE WATERS THROUGH FRIDAY
NIGHT SO WE HAVE A SLIGHT CHANCE POP DURING THIS TIME PERIOD. COOLER
HIGH PRESSURE WILL BUILD IN NEXT WEEKEND. ABOVE NORMAL TEMPERATURES
ANTICIPATED WEDNESDAY THROUGH FRIDAY WITH A RETURN TO SEASONAL NORMS
NEXT WEEKEND.
&&
.AVIATION /02Z SUNDAY THROUGH THURSDAY/...
VFR. GUSTY WEST WINDS WILL COMMENCE WITH THE ONSET OF MIXING
AROUND 14Z SUNDAY CONTINUE THROUGH THE END OF THE TAF PERIOD.
EXTENDED AVIATION OUTLOOK...THERE ARE NO CONCERNS AT THIS TIME.
&&
.MARINE...
TONIGHT...CONDITIONS EARLY IN THE OVERNIGHT WILL BE QUIET AS WINDS
TURN MORE SOUTHWESTERLY AND ARE LESS THAN 15 KTS AHEAD OF AN
APPROACHING FRONT. THEN...LATE TONIGHT THE FRONT WILL PUSH OFFSHORE
AND THE PRESSURE GRADIENT WILL TIGHTEN. WINDS WILL BECOME MORE
WESTERLY AND STEADILY INCREASE THROUGH SUNRISE. THE BEST MIXING WILL
OCCUR OVER THE OUTER WATERS WHERE THE WARMEST SST/S RESIDE. WITH
FREQUENT 25 KT GUSTS EXPECTED LATE TONIGHT...HAVE HOISTED A SMALL
CRAFT ADVISORY FOR THE OUTER GEORGIA WATERS.
GUSTY OFFSHORE WINDS WILL JUSTIFY SMALL CRAFT ADVISORIES ALL
NEARSHORE MARINE ZONES LATE SUNDAY MORNING INTO EARLY SUNDAY
EVENING...THEN WINDS SHOULD DIMINISH BELOW SCA LEVELS ACROSS
NEARSHORE WATERS FOR THE BALANCE OF SUNDAY NIGHT. A DEEPER MARINE
BOUNDARY LAYER WILL SUPPORT SMALL CRAFT ADVISORY GUSTS AND ELEVATED
SEAS BEYOND 20 NM SUNDAY THROUGH SUNDAY NIGHT. IN ALL AREAS...WINDS
WILL VEER THROUGH NW TOWARD THE NORTH SUNDAY NIGHT INTO MONDAY
MORNING.
MONDAY WILL BEGIN WITH N/NW WINDS 10-15 KNOTS OVER MOST AREAS...THEN
AS HIGH PRESSURE SHIFTS OVER THE WATERS THE PRESSURE GRADIENT WILL
SLACKEN AND WINDS WILL BECOME VARIABLE LESS THAN 10 KT MONDAY
AFTERNOON INTO MONDAY EVENING. AS A TROUGH OF LOW PRESSURE
APPROACHES THE WATERS OVERNIGHT MONDAY NIGHT THROUGH TUESDAY...WINDS
SHOULD BECOME S/SW 15 KT OR LESS...THEN WINDS WILL SHIFT TO THE W/NW
MAINLY LESS THAN 20 KT AS THE TROUGH PUSHES OFFSHORE TUESDAY NIGHT
INTO WEDNESDAY. EVENTUALLY...HIGH PRESSURE WILL BUILD FROM THE NORTH
AND WINDS WILL VEER THROUGH THE N TO THE NE BY THURSDAY. GUIDANCE
HOLDS WINDS BELOW SCA LEVELS.
OFFSHORE WINDS WILL PRODUCE WINDS 2-4 FT WITHIN NEARSHORE WATERS AND
AS HIGH AS 5-6 FT BEYOND 20 NM SUNDAY INTO SUNDAY NIGHT. THEN...SEAS
1-3 FT WILL REMAIN COMMON MONDAY THROUGH WEDNESDAY. SEAS COULD BUILD
TO 2-4 FT LATE IN THE FORECAST PERIOD.
&&
.FIRE WEATHER...
AFTER A DRY COLD FRONT PASSES OVERNIGHT...STRONG/GUSTY WEST WINDS
ARE EXPECTED TO ACCOMPANY NEAR CRITICAL RELATIVE HUMIDITY SUNDAY.
PER COORDINATION WITH FIRE WEATHER CUSTOMERS...ISSUED A FIRE DANGER
STATEMENT TO ADDRESS IMPACTS OF WIND AND LOW RELATIVE HUMIDITY
SUNDAY.
&&
.CHS WATCHES/WARNINGS/ADVISORIES...
GA...NONE.
SC...LAKE WIND ADVISORY FROM 10 AM TO 8 PM EST SUNDAY FOR SCZ045.
MARINE...SMALL CRAFT ADVISORY FROM 10 AM TO 8 PM EST SUNDAY FOR AMZ330-
350-352-354.
SMALL CRAFT ADVISORY FROM 4 AM SUNDAY TO 5 AM EST MONDAY FOR
AMZ374.
&&
$$
ST
AREA FORECAST DISCUSSION
NWS CHARLESTON SC
915 PM EST SAT FEB 2 2013
.SYNOPSIS...
A COLD FRONT WILL CROSS THE REGION TONIGHT AND HIGH PRESSURE WILL
PREVAIL SUNDAY AND MONDAY. WEAK LOW PRESSURE WILL PASS JUST SOUTH
OF THE AREA TUESDAY...FOLLOWED BY HIGH PRESSURE INTO LATE WEEK.
ANOTHER COLD FRONT COULD PUSH INTO THE SOUTHEAST UNITED STATES
BEFORE STALLING LATE WEEK INTO NEXT WEEKEND.
&&
.NEAR TERM /UNTIL 6 AM SUNDAY MORNING/...
A COLD FRONT IS STEADILY APPROACHING FROM THE WEST AND IS ON
TARGET TO PUSH THROUGH THE FORECAST AREA OVERNIGHT. SHOWER
ACTIVITY MOVING ACROSS PORTIONS OF THE THE SOUTH CAROLINA
MIDLANDS AND EAST-CENTRAL GEORGIA ARE SHOWING SIGNS OF
WEAKENING/DISSIPATING AS THEY MOVE EAST AND ENCOUNTER INCREASINGLY
DRIER AIR. THE LATEST RUNS OF THE H3R AND RAP MODELS SUPPORT
KEEPING CONDITIONS DRY OVERNIGHT...WHICH LOOKS REASONABLE GIVEN
CURRENT RADAR AND SATELLITE TRENDS.
TEMPERATURES HAVE FALLEN QUICKLY THIS EVENING WITH CALM/LIGHT
WINDS AND LOW DEWPOINTS IN PLACE. IN FACT...SOME AREAS ARE ALREADY
APPROACHING FORECAST MINIMA ACROSS THE COASTAL COUNTIES. SHOULD
SEE TEMPERATURES STEADY OR EVEN RISE OVER THE NEXT FEW HOURS AS
CLOUDS INCREASE FROM THE WEST SO WILL NOT MAKE ANY CHANGES TO THE
LOW TEMPERATURE FORECAST. LOWS FROM THE MID-UPPER 30S INLAND TO
THE UPPER 30-LOWER 40S AT THE COAST LOOK FINE FOR NOW.
&&
.SHORT TERM /6 AM SUNDAY MORNING THROUGH TUESDAY/...
SUNDAY...ANY LINGERING CLOUDS EARLY WILL GIVE WAY TO SUNNY/MOSTLY
SUNNY SKIES. A TIGHT SURFACE PRESSURE GRADIENT AND A DEEPENING MIXED
LAYER WILL SUPPORT WEST WINDS GUSTING AS HIGH AS 30-35 MPH
ESPECIALLY DURING THE AFTERNOON. TEMPERATURES SHOULD TOP OUT IN THE
LOWER 60S AT MANY LOCATIONS...AND DOWNSLOPE FLOW/DEWPOINTS LOWERING
INTO THE UPPER 20S COULD SUPPORT HIGHS IN THE MID 60S AT A FEW
LOCATIONS NEAR THE COAST AND ACROSS SOUTHERN COUNTIES.
A COMBINATION OF COLD ADVECTION AND RADIATIVE COOLING AS SURFACE
WINDS BECOME NEARLY CALM TOWARD DAYBREAK WILL PUSH TEMPERATURES
INTO THE UPPER 20S TO LOWER 30S AT MANY LOCATIONS. THEN...AS HIGH
CLOUDS INCREASE AND THICKEN FROM THE WEST MONDAY TEMPERATURES SHOULD
TOP OUT A COUPLE OF DEGREES COOLER THAN THOSE OF SUNDAY
AFTERNOON...IN THE UPPER 50S TO LOWER 60S MOST LOCATIONS...AND WINDS
WILL REMAIN MUCH LIGHTER THAN THOSE OF SUNDAY.
SKIES WILL BECOME MOSTLY CLOUDY MONDAY NIGHT AS MID/HIGH LEVEL
CLOUDS DEVELOPING WITHIN AN UPSTREAM ISENTROPIC ASCENT REGIME STREAM
EAST ACROSS THE REGION. THIS SHOULD HOLD LOW TEMPERATURES 35-40F
INLAND AND MID 40S TO AROUND 50 AT THE COAST. IN FACT...OVERNIGHT
TEMPERATURES COULD BECOME UNSTEADY AND EVEN RISE A FEW DEGREES IN
SOME LOCATIONS.
THE BULK OF 02/12Z GUIDANCE SUGGESTS THAT A WEAK SHORTWAVE AND
ASSOCIATED SUBTLE FORCING FOR ASCENT/BAND OF ENHANCED MOISTURE WILL
PASS THROUGH THE REGION TUESDAY. NUDGED THE FORECAST IN THE
DIRECTION OF THE 12Z GFS WITH SLIGHT CHANCE POPS ACROSS SOUTHERN
COUNTIES...STILL LOWER POPS AND LESS COVERAGE OF POPS 15 PERCENT OR
GREATER THAN DEPICTED BY THE GFS. ANY QPF SHOULD REMAIN PALTRY...IN
MOST CASES LESS THAN ONE-TENTH OF AN INCH.
LAKE WINDS...DUE TO FREQUENT GUSTS TO AT LEAST 25 KNOTS EXPECTED
OVER LAKE MOULTRIE LATE SUNDAY MORNING/EARLY SUNDAY AFTERNOON
THROUGH LATE SUNDAY AFTERNOON/EARLY SUNDAY EVENING...ISSUED A LAKE
WIND ADVISORY FOR THE LAKE VALID 10 AM UNTIL 8 PM SUNDAY.
&&
.LONG TERM /TUESDAY NIGHT THROUGH SATURDAY/...
A RELATIVELY ZONAL FLOW WILL EXIST IN THE LONG TERM ALTHOUGH A BROAD
RIDGE COULD DEVELOP NEXT WEEKEND. A SHORTWAVE DISTURBANCE WILL MOVE
THROUGH ON THURSDAY...PUSHING A COLD FRONT SLOWLY SOUTHEAST THROUGH
THE AREA. THIS FRONT MAY STALL ACROSS THE WATERS THROUGH FRIDAY
NIGHT SO WE HAVE A SLIGHT CHANCE POP DURING THIS TIME PERIOD. COOLER
HIGH PRESSURE WILL BUILD IN NEXT WEEKEND. ABOVE NORMAL TEMPERATURES
ANTICIPATED WEDNESDAY THROUGH FRIDAY WITH A RETURN TO SEASONAL NORMS
NEXT WEEKEND.
&&
.AVIATION /02Z SUNDAY THROUGH THURSDAY/...
VFR. GUSTY WEST WINDS WILL COMMENCE WITH THE ONSET OF MIXING
AROUND 14Z SUNDAY CONTINUE THROUGH THE END OF THE TAF PERIOD.
EXTENDED AVIATION OUTLOOK...THERE ARE NO CONCERNS AT THIS TIME.
&&
.MARINE...
TONIGHT...CONDITIONS EARLY IN THE OVERNIGHT WILL BE QUIET AS WINDS
TURN MORE SOUTHWESTERLY AND ARE LESS THAN 15 KTS AHEAD OF AN
APPROACHING FRONT. THEN...LATE TONIGHT THE FRONT WILL PUSH OFFSHORE
AND THE PRESSURE GRADIENT WILL TIGHTEN. WINDS WILL BECOME MORE
WESTERLY AND STEADILY INCREASE THROUGH SUNRISE. THE BEST MIXING WILL
OCCUR OVER THE OUTER WATERS WHERE THE WARMEST SST/S RESIDE. WITH
FREQUENT 25 KT GUSTS EXPECTED LATE TONIGHT...HAVE HOISTED A SMALL
CRAFT ADVISORY FOR THE OUTER GEORGIA WATERS.
GUSTY OFFSHORE WINDS WILL JUSTIFY SMALL CRAFT ADVISORIES ALL
NEARSHORE MARINE ZONES LATE SUNDAY MORNING INTO EARLY SUNDAY
EVENING...THEN WINDS SHOULD DIMINISH BELOW SCA LEVELS ACROSS
NEARSHORE WATERS FOR THE BALANCE OF SUNDAY NIGHT. A DEEPER MARINE
BOUNDARY LAYER WILL SUPPORT SMALL CRAFT ADVISORY GUSTS AND ELEVATED
SEAS BEYOND 20 NM SUNDAY THROUGH SUNDAY NIGHT. IN ALL AREAS...WINDS
WILL VEER THROUGH NW TOWARD THE NORTH SUNDAY NIGHT INTO MONDAY
MORNING.
MONDAY WILL BEGIN WITH N/NW WINDS 10-15 KNOTS OVER MOST AREAS...THEN
AS HIGH PRESSURE SHIFTS OVER THE WATERS THE PRESSURE GRADIENT WILL
SLACKEN AND WINDS WILL BECOME VARIABLE LESS THAN 10 KT MONDAY
AFTERNOON INTO MONDAY EVENING. AS A TROUGH OF LOW PRESSURE
APPROACHES THE WATERS OVERNIGHT MONDAY NIGHT THROUGH TUESDAY...WINDS
SHOULD BECOME S/SW 15 KT OR LESS...THEN WINDS WILL SHIFT TO THE W/NW
MAINLY LESS THAN 20 KT AS THE TROUGH PUSHES OFFSHORE TUESDAY NIGHT
INTO WEDNESDAY. EVENTUALLY...HIGH PRESSURE WILL BUILD FROM THE NORTH
AND WINDS WILL VEER THROUGH THE N TO THE NE BY THURSDAY. GUIDANCE
HOLDS WINDS BELOW SCA LEVELS.
OFFSHORE WINDS WILL PRODUCE WINDS 2-4 FT WITHIN NEARSHORE WATERS AND
AS HIGH AS 5-6 FT BEYOND 20 NM SUNDAY INTO SUNDAY NIGHT. THEN...SEAS
1-3 FT WILL REMAIN COMMON MONDAY THROUGH WEDNESDAY. SEAS COULD BUILD
TO 2-4 FT LATE IN THE FORECAST PERIOD.
&&
.FIRE WEATHER...
AFTER A DRY COLD FRONT PASSES OVERNIGHT...STRONG/GUSTY WEST WINDS
ARE EXPECTED TO ACCOMPANY NEAR CRITICAL RELATIVE HUMIDITY SUNDAY.
PER COORDINATION WITH FIRE WEATHER CUSTOMERS...ISSUED A FIRE DANGER
STATEMENT TO ADDRESS IMPACTS OF WIND AND LOW RELATIVE HUMIDITY
SUNDAY.
&&
.CHS WATCHES/WARNINGS/ADVISORIES...
GA...NONE.
SC...LAKE WIND ADVISORY FROM 10 AM TO 8 PM EST SUNDAY FOR SCZ045.
MARINE...SMALL CRAFT ADVISORY FROM 10 AM TO 8 PM EST SUNDAY FOR AMZ330-
350-352-354.
SMALL CRAFT ADVISORY FROM 4 AM SUNDAY TO 5 AM EST MONDAY FOR
AMZ374.
&&
$$
ST
AREA FORECAST DISCUSSION
NWS CHARLESTON SC
640 PM EST SAT FEB 2 2013
.SYNOPSIS...
A COLD FRONT WILL CROSS THE REGION TONIGHT AND HIGH PRESSURE WILL
PREVAIL SUNDAY AND MONDAY. WEAK LOW PRESSURE WILL PASS JUST SOUTH
OF THE AREA TUESDAY...FOLLOWED BY HIGH PRESSURE INTO LATE WEEK.
ANOTHER COLD FRONT COULD PUSH INTO THE SOUTHEAST UNITED STATES
BEFORE STALLING LATE WEEK INTO NEXT WEEKEND.
&&
.NEAR TERM /UNTIL 6 AM SUNDAY MORNING/...
A COLD FRONT WILL APPROACH FROM THE WEST TONIGHT AND PUSH OFFSHORE
EARLY SUNDAY. MODELS ARE INSISTENT THAT THE BAND OF LIGHT
PRECIPITATION THAT IS ACCOMPANYING THE FRONT WILL DISSIPATE PRIOR
TO REACHING THIS FAR EAST. CONSIDERING WINDS ARE PROGGED TO VEER
SOUTHWEST AND EVENTUALLY WEST AHEAD OF THE FRONT...THIS SEEMS TO
BE A REASONABLE SOLUTION. WILL KEEP THE FORECAST DRY AS A RESULT.
DEWPOINTS ARE PROVING DIFFICULT THIS EVENING. A PRONOUNCED SPIKE
HAS BEEN OBSERVED IN THE WAKE OF A SEA BREEZE CIRCULATION WHILE
FARTHER INLAND THEY REMAIN QUITE LOW. H3R AND RAP KEEP DEWPOINTS
QUITE LOW INLAND FOR MUCH OF THE NIGHT AS THE SEA BREEZE BREAKS
DOWN AND NEVER CLEARS AREAS WEST OF I-95. ITS UNCLEAR HOW MUCH OF
A RECOVERY DEWPOINTS WILL HAVE AHEAD OF THE FRONT...BUT THERE IS
ENOUGH EVIDENCE TO SUPPORT LOWERING DEWPOINTS INLAND BY ABOUT 5
DEGREES OR SO. SKIES WILL REMAIN CLEAR UNTIL THE FRONT DRAWS
CLOSER...AFTER WHICH CLOUDS WILL BEGIN TO THICKEN. PARTLY TO
MOSTLY CLOUDY SKIES LOOK REASONABLE...BUT DID NEED TO ADJUST SKY
GRIDS SLIGHTLY TO TAKE CURRENT TIMING TRENDS INTO ACCOUNT. LOWS
LOOK FINE FOR NOW.
&&
.SHORT TERM /6 AM SUNDAY MORNING THROUGH TUESDAY/...
SUNDAY...ANY LINGERING CLOUDS EARLY WILL GIVE WAY TO SUNNY/MOSTLY
SUNNY SKIES. A TIGHT SURFACE PRESSURE GRADIENT AND A DEEPENING MIXED
LAYER WILL SUPPORT WEST WINDS GUSTING AS HIGH AS 30-35 MPH
ESPECIALLY DURING THE AFTERNOON. TEMPERATURES SHOULD TOP OUT IN THE
LOWER 60S AT MANY LOCATIONS...AND DOWNSLOPE FLOW/DEWPOINTS LOWERING
INTO THE UPPER 20S COULD SUPPORT HIGHS IN THE MID 60S AT A FEW
LOCATIONS NEAR THE COAST AND ACROSS SOUTHERN COUNTIES.
A COMBINATION OF COLD ADVECTION AND RADIATIVE COOLING AS SURFACE
WINDS BECOME NEARLY CALM TOWARD DAYBREAK WILL PUSH TEMPERATURES
INTO THE UPPER 20S TO LOWER 30S AT MANY LOCATIONS. THEN...AS HIGH
CLOUDS INCREASE AND THICKEN FROM THE WEST MONDAY TEMPERATURES SHOULD
TOP OUT A COUPLE OF DEGREES COOLER THAN THOSE OF SUNDAY
AFTERNOON...IN THE UPPER 50S TO LOWER 60S MOST LOCATIONS...AND WINDS
WILL REMAIN MUCH LIGHTER THAN THOSE OF SUNDAY.
SKIES WILL BECOME MOSTLY CLOUDY MONDAY NIGHT AS MID/HIGH LEVEL
CLOUDS DEVELOPING WITHIN AN UPSTREAM ISENTROPIC ASCENT REGIME STREAM
EAST ACROSS THE REGION. THIS SHOULD HOLD LOW TEMPERATURES 35-40F
INLAND AND MID 40S TO AROUND 50 AT THE COAST. IN FACT...OVERNIGHT
TEMPERATURES COULD BECOME UNSTEADY AND EVEN RISE A FEW DEGREES IN
SOME LOCATIONS.
THE BULK OF 02/12Z GUIDANCE SUGGESTS THAT A WEAK SHORTWAVE AND
ASSOCIATED SUBTLE FORCING FOR ASCENT/BAND OF ENHANCED MOISTURE WILL
PASS THROUGH THE REGION TUESDAY. NUDGED THE FORECAST IN THE
DIRECTION OF THE 12Z GFS WITH SLIGHT CHANCE POPS ACROSS SOUTHERN
COUNTIES...STILL LOWER POPS AND LESS COVERAGE OF POPS 15 PERCENT OR
GREATER THAN DEPICTED BY THE GFS. ANY QPF SHOULD REMAIN PALTRY...IN
MOST CASES LESS THAN ONE-TENTH OF AN INCH.
LAKE WINDS...DUE TO FREQUENT GUSTS TO AT LEAST 25 KNOTS EXPECTED
OVER LAKE MOULTRIE LATE SUNDAY MORNING/EARLY SUNDAY AFTERNOON
THROUGH LATE SUNDAY AFTERNOON/EARLY SUNDAY EVENING...ISSUED A LAKE
WIND ADVISORY FOR THE LAKE VALID 10 AM UNTIL 8 PM SUNDAY.
&&
.LONG TERM /TUESDAY NIGHT THROUGH SATURDAY/...
A RELATIVELY ZONAL FLOW WILL EXIST IN THE LONG TERM ALTHOUGH A BROAD
RIDGE COULD DEVELOP NEXT WEEKEND. A SHORTWAVE DISTURBANCE WILL MOVE
THROUGH ON THURSDAY...PUSHING A COLD FRONT SLOWLY SOUTHEAST THROUGH
THE AREA. THIS FRONT MAY STALL ACROSS THE WATERS THROUGH FRIDAY
NIGHT SO WE HAVE A SLIGHT CHANCE POP DURING THIS TIME PERIOD. COOLER
HIGH PRESSURE WILL BUILD IN NEXT WEEKEND. ABOVE NORMAL TEMPERATURES
ANTICIPATED WEDNESDAY THROUGH FRIDAY WITH A RETURN TO SEASONAL NORMS
NEXT WEEKEND.
&&
.AVIATION /00Z SUNDAY THROUGH THURSDAY/...
VFR. GUSTY WEST WINDS WILL COMMENCE WITH THE ONSET OF MIXING
AROUND 14Z SUNDAY CONTINUE THROUGH THE END OF THE TAF PERIOD.
EXTENDED AVIATION OUTLOOK...THERE ARE NO CONCERNS AT THIS TIME.
&&
.MARINE...
TONIGHT...CONDITIONS EARLY IN THE OVERNIGHT WILL BE QUIET AS WINDS
TURN MORE SOUTHWESTERLY AND ARE LESS THAN 15 KTS AHEAD OF AN
APPROACHING FRONT. THEN...LATE TONIGHT THE FRONT WILL PUSH OFFSHORE
AND THE PRESSURE GRADIENT WILL TIGHTEN. WINDS WILL BECOME MORE
WESTERLY AND STEADILY INCREASE THROUGH SUNRISE. THE BEST MIXING WILL
OCCUR OVER THE OUTER WATERS WHERE THE WARMEST SST/S RESIDE. WITH
FREQUENT 25 KT GUSTS EXPECTED LATE TONIGHT...HAVE HOISTED A SMALL
CRAFT ADVISORY FOR THE OUTER GEORGIA WATERS.
GUSTY OFFSHORE WINDS WILL JUSTIFY SMALL CRAFT ADVISORIES ALL
NEARSHORE MARINE ZONES LATE SUNDAY MORNING INTO EARLY SUNDAY
EVENING...THEN WINDS SHOULD DIMINISH BELOW SCA LEVELS ACROSS
NEARSHORE WATERS FOR THE BALANCE OF SUNDAY NIGHT. A DEEPER MARINE
BOUNDARY LAYER WILL SUPPORT SMALL CRAFT ADVISORY GUSTS AND ELEVATED
SEAS BEYOND 20 NM SUNDAY THROUGH SUNDAY NIGHT. IN ALL AREAS...WINDS
WILL VEER THROUGH NW TOWARD THE NORTH SUNDAY NIGHT INTO MONDAY
MORNING.
MONDAY WILL BEGIN WITH N/NW WINDS 10-15 KNOTS OVER MOST AREAS...THEN
AS HIGH PRESSURE SHIFTS OVER THE WATERS THE PRESSURE GRADIENT WILL
SLACKEN AND WINDS WILL BECOME VARIABLE LESS THAN 10 KT MONDAY
AFTERNOON INTO MONDAY EVENING. AS A TROUGH OF LOW PRESSURE
APPROACHES THE WATERS OVERNIGHT MONDAY NIGHT THROUGH TUESDAY...WINDS
SHOULD BECOME S/SW 15 KT OR LESS...THEN WINDS WILL SHIFT TO THE W/NW
MAINLY LESS THAN 20 KT AS THE TROUGH PUSHES OFFSHORE TUESDAY NIGHT
INTO WEDNESDAY. EVENTUALLY...HIGH PRESSURE WILL BUILD FROM THE NORTH
AND WINDS WILL VEER THROUGH THE N TO THE NE BY THURSDAY. GUIDANCE
HOLDS WINDS BELOW SCA LEVELS.
OFFSHORE WINDS WILL PRODUCE WINDS 2-4 FT WITHIN NEARSHORE WATERS AND
AS HIGH AS 5-6 FT BEYOND 20 NM SUNDAY INTO SUNDAY NIGHT. THEN...SEAS
1-3 FT WILL REMAIN COMMON MONDAY THROUGH WEDNESDAY. SEAS COULD BUILD
TO 2-4 FT LATE IN THE FORECAST PERIOD.
&&
.FIRE WEATHER...
AFTER A DRY COLD FRONT PASSES OVERNIGHT...STRONG/GUSTY WEST WINDS
ARE EXPECTED TO ACCOMPANY NEAR CRITICAL RELATIVE HUMIDITY SUNDAY.
PER COORDINATION WITH FIRE WEATHER CUSTOMERS...ISSUED A FIRE DANGER
STATEMENT TO ADDRESS IMPACTS OF WIND AND LOW RELATIVE HUMIDITY
SUNDAY.
&&
.CHS WATCHES/WARNINGS/ADVISORIES...
GA...NONE.
SC...LAKE WIND ADVISORY FROM 10 AM TO 8 PM EST SUNDAY FOR SCZ045.
MARINE...SMALL CRAFT ADVISORY FROM 10 AM TO 8 PM EST SUNDAY FOR AMZ330-
350-352-354.
SMALL CRAFT ADVISORY FROM 4 AM SUNDAY TO 5 AM EST MONDAY FOR
AMZ374.
&&
$$
ST
AREA FORECAST DISCUSSION
NWS LINCOLN IL
825 PM CST SAT FEB 2 2013
.DISCUSSION...
ISSUED 824 PM CST SAT FEB 2 2013
AREA OF LIGHT SNOW DROPPING SOUTHEAST ACROSS IOWA/NORTHERN
MISSOURI HAS BEEN HANDLED FAIRLY WELL ON THE RECENT HRRR AND RAP
RUNS. HEAVIER SNOW AXIS HAS BEEN TRENDING TOWARD AREAS ALONG/WEST
OF THE MISSISSIPPI RIVER...BUT THE SNOW AREA WILL BEGIN MOVING
INTO THE WESTERN CWA IN THE NEXT HOUR OR TWO. MOST OF THE HEAVIER
PRECIP HAS BEEN ASSOCIATED WITH A VORT MAX DROPPING SOUTHEAST
THROUGH THE MID-MISSISSIPPI VALLEY...BUT SOME LIGHT SNOW IS ALSO
OCCURRING FURTHER NORTH CLOSER TO THE CENTER OF THE INCOMING
CLIPPER SYSTEM. GREATEST PRECIP THREAT ACROSS THE WESTERN CWA WILL
BE THROUGH ABOUT 2 AM...WITH THE EASTERN CWA MAINLY AFTER
MIDNIGHT.
ZONES/GRIDS WERE UPDATED EARLIER TO REFLECT THESE PRECIPITATION
TRENDS...AS WELL AS ADJUST THE TEMPERATURE TRENDS.
GEELHART
&&
.AVIATION...
ISSUED 519 PM CST SAT FEB 2 2013
SCATTERED SNOW SHOWERS EARLY THIS EVENING MAY REDUCE VISIBILITY TO
MVFR RANGE AT TIMES BETWEEN KDEC/KCMI/KBMI. MAIN SNOW CONCERN IS
WITH A LARGE AREA OF PRECIPITATION CURRENTLY IN WESTERN IOWA.
LATEST MODEL GUIDANCE TRACKS IT INTO WEST CENTRAL ILLINOIS...WITH
AWIPS TIME-OF-ARRIVAL TOOL SUGGESTING ARRIVAL AROUND KSPI IN THE
03-04Z TIME FRAME. UPSTREAM OBS INDICATE VISIBILITY POTENTIALLY
DOWN TO 2 MILES OR LESS WITH THE HEAVIER SNOW...WHICH WOULD BE
MOST LIKELY FURTHER WEST TOWARD THE MISSISSIPPI RIVER...BUT WILL
GO WITH 2 MILE VISIBILITY AT KSPI AND AROUND 4 MILES ELSEWHERE.
CEILINGS EXPECTED TO REMAIN BELOW 3000 FEET THROUGH ABOUT MID
MORNING. SOME CLEARING WILL ALLOW GUSTY NORTHWEST WINDS TO MIX
DOWN TO THE SURFACE DURING THE MIDDAY AND AFTERNOON...BEFORE
CLOUDS BEGIN TO INCREASE AGAIN LATE AFTERNOON AHEAD OF THE NEXT
SYSTEM.
GEELHART
&&
.PREV DISCUSSION...
ISSUED 300 PM CST SAT FEB 2 2013
A COMBINATION OF SURFACE TROUGHS AND UPPER LEVEL SHORTWAVES WILL
KEEP LIGHT SNOW IN THE SHORT TERM FORECAST. THEIR TRACKS WILL ALSO
BE FAVORABLE FOR KEEPING COLDER AIR IN PLACE ACROSS CENTRAL IL. WE
WILL WARM TO AROUND NORMAL FOR THE EARLY PART OF NEXT WEEK...BUT
ABOVE NORMAL TEMPS WILL BE DELAYED UNTIL THURSDAY AND SATURDAY. A
WEAK COLD FRONTAL PASSAGE LATER THURSDAY WILL COOL DOWN TEMPS
SLIGHTLY FOR FRIDAY.
SHORT TERM...TONIGHT THROUGH MONDAY NIGHT.
THE WATER VAPOR SATELLITE SHOWS A MYRIAD OF SHORTWAVES UPSTREAM
EXTENDING FROM NW IL TO THE NORTHERN PLAINS AND INTO SOUTHWEST
CANADA. THE DEEP UPPER TROUGH DOMINATING THE EASTERN 2/3RDS OF THE
COUNTRY WILL KEEP THAT NORTHWEST FLOW IN PLACE...SENDING THOSE
SHORTWAVES DIRECTLY AT AMERICA/S HEARTLAND INTO EARLY NEXT WEEK.
WE HAVE A TRAILING SECONDARY WAVE TRIGGERING LIGHT SNOW ACROSS
OUR NW COUNTIES THIS AFTERNOON. THAT AREA OF SNOW WILL PROGRESS
SOUTHEASTWARD THIS EVENING...WITH A BREAK IN THE SNOWFALL EXPECTED
FOR A FEW HOURS. THEN A MORE POTENT SHORTWAVE WILL MOVE SOUTHEAST
FROM EASTERN SOUTH DAKOTA AND PASS ALONG THE ILLINOIS-MISSOURI
BORDER LATER TONIGHT. ASSUMING THAT TRACK TONIGHT...THE BAND OF
HEAVIER SNOW /ONE INCH/ WILL BE CENTERED BETWEEN SPRINGFIELD AND
ST LOUIS...WITH UP TO AN INCH REACHING NEAR JACKSONVILLE. SNOW
TOTALS OF ONE HALF INCH COULD EXTEND AS FAR AS PEORIA TO LINCOLN
TO MATTOON AND LAWRENCEVILLE. NORTHEAST OF THAT LINE...MAINLY A DUSTING
IS EXPECTED. THE GFS/NAM/CANADIAN GEM/HRRR/RAP ALL POINT TOWARD
THAT GENERAL SCENARIO.
THE SNOW SHOULD COME TO AN END BY SUNDAY MORNING EVERYWHERE BUT
POSSIBLY ALONG THE INDIANA BORDER FROM DANVILLE TO LAWRENCEVILLE.
OTHERWISE SUNDAY WILL SEE DECREASING CLOUDS BUT BLUSTERY NORTHWEST
WINDS AND CHILLY CONDITIONS WITH HIGHS IN THE MID TO UPPER 20S.
MONDAY WILL SEE A LOW PRESSURE SYSTEM AND UPPER SHORTWAVE PASS
ACROSS ILLINOIS. IT APPEARS THAT THE BEST FORCING FOR LIGHT SNOW
WILL RESIDE ACROSS FAR NORTHERN ILLINOIS AND SOUTHERN
WISCONSIN...WHERE ISENTROPIC LIFT WILL COINCIDE BEST WITH MOISTURE
AND LOW CONDENSATION PRESSURE DEFICITS. THE SURFACE LOW WILL PASS
ACROSS CENTRAL IL BETWEEN 18Z MON AND 00Z TUE...WITH AN
INTENSIFICATION OF PRECIP JUST AHEAD OF THE LOW IN OUR EAST AND
SOUTHEASTERN COUNTIES MON AFTERNOON. WE COULD SEE 0.5 TO 1 INCH OF
SNOW SOUTHEAST OF A LINE FROM CHAMPAIGN TO EFFINGHAM...WITH LITTLE
TO NO PRECIP WEST OF A LINE FROM BMI TO TAYLORVILLE. THE SNOW
COULD LINGER INTO MONDAY EVENING NEAR LWV.
LONG TERM...TUESDAY THROUGH SATURDAY.
A BRIEF APPEARANCE OF HIGH PRESSURE TUESDAY MORNING WILL BE PUSHED
ASIDE BY THE NEXT SHORTWAVE MOVING FROM MINNESOTA ACROSS
WISCONSIN...AND A COLD FRONT EXTENDING SOUTH ACROSS IOWA. THE
ASSOCIATED SURFACE LOW WILL TRACK ACROSS WISC AS WELL...ALONG WITH
THE BEST FORCING FOR PRECIP. WE DO NOT EXPECT MUCH IN THE WAY OF
SNOW IN OUR COUNTIES...ALTHOUGH SOME FLURRIES MAY DEVELOP NORTH OF
A LINE FROM PEORIA TO CHAMPAIGN. THE TRACK OF THIS SYSTEM HAS
CHANGED FROM YESTERDAYS MODELS...PUSHING IT FARTHER NORTH NOW.
WEDNESDAY LOOKS TO BE DRY AND SLIGHTLY WARMER WITH HIGHS IN THE
MID TO UPPER 30S. THE NEXT COLD FRONT LOOKS TO ARRIVE ON
THURSDAY...WITH RAIN OR SNOW POSSIBLE THURSDAY MORNING BUT MAINLY
RAIN THURSDAY AFTERNOON. COLD AIR FILTERING IN BEHIND THAT FRONT
MAY CHANGE ANY LINGERING PRECIP IN THE EVENING BACK OVER TO
LIGHT SNOW BY LATE EVENING...AS TEMPS DIP BACK BELOW FREEZING.
FRIDAY LOOKS TO BE A LITTLE COOLER THAN THURSDAYS HIGHS AHEAD OF
THE FRONT...BUT STILL INTO THE UPPER 30S OR LOW 40S. SATURDAY WILL
SEE INCREASING CLOUDS AHEAD OF A MORE PROMINENT LOW PRESSURE
SYSTEM ARRIVING ON SUNDAY. SOME LIGHT RAIN WILL BE POSSIBLE IN OUR
WESTERN COUNTIES BY SATURDAY AFTERNOON...BUT THE TRENDS THE LAST
COUPLE OF DAYS HAVE BEEN TO SLOW DOWN THE ARRIVAL OF RAIN ON
SATURDAY. WE MAY HAVE A BETTER CHANCE OF A DRY DAY ON SATURDAY AS
ADDITIONAL MODEL RUNS COME IN OVER THE NEXT FEW DAYS. HIGHS ON
SATURDAY SHOULD HAVE ENOUGH SUPPORT FOR SUNSHINE AND SOUTHERLY
WINDS TO REACH THE MID TO UPPER 40S.
SHIMON
&&
.ILX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS INDIANAPOLIS IN
920 PM EST SAT FEB 2 2013
.UPDATE...
THE AVIATION SECTION HAS BEEN UPDATED BELOW
&&
.SYNOPSIS...
ISSUED AT 150 PM EST SAT FEB 2 2013
A QUICK MOVING COLD FRONT WILL EXIT CENTRAL INDIANA EARLY THIS
EVENING...LEAVING COLD NORTHWEST FLOW IN PLACE. A FEW FLURRIES
WILL BE POSSIBLE THIS EVENING AS COLD AIR BUILDS ACROSS CENTRAL
INDIANA AND A WEAK UPPER LEVEL WEATHER DISTURBANCE PASSES ALOFT.
DRY BUT COLD WEATHER IS EXPECTED ON SUNDAY AND SUNDAY NIGHT AS
HIGH PRESSURE OVER THE CENTRAL PLAINS PUSHES THROUGH THE OHIO VALLEY.
ON MONDAY...ANOTHER LOW PRESSURE SYSTEM WILL PUSH TOWARD CENTRAL
INDIANA FROM THE WEST. THIS WILL ONCE AGAIN BRING CHANCES FOR
ACCUMULATING SNOW TO CENTRAL INDIANA.
DRY WEATHER IS THEN EXPECTED BY THE MIDDLE OF THE WORK WEEK BEFORE
YET ANOTHER SYSTEM PASSES ACROSS INDIANA ON THURSDAY...BRINGING
MORE CHANCES FOR PRECIPITATION.
&&
.NEAR TERM /REST OF TONIGHT/...
ISSUED AT 651 PM EST SAT FEB 2 2013
SURFACE LOW WILL DRIFT ACROSS CENTRAL INDIANA TONIGHT RESULTING IN
INTERMITTENT SNOW SHOWERS. REMOVED MENTION OF FREEZING RAIN FROM
PREVIOUS FORECAST. DECENT COLD AIR ADVECTION AND CURRENT SURFACE
TEMPS IN THE UPPER 20S SHOULD KEEP PRECIP IN THE FORM OF SNOW.
LITTLE TO NO ACCUMULATION IS EXPECTED DUE TO LACK OF MOISTURE AND
WEAK LIFT.
&&
.SHORT TERM /SUNDAY THROUGH TUESDAY/...
ISSUED AT 150 PM EST SAT FEB 2 2013
MAIN FORECAST CHALLENGE DURING THIS PERIOD WILL BE POPS ON MONDAY
WITH THE APPROACHING STORM SYSTEM.
ON SUNDAY THE GFS AND NAM BUILD A RIDGE OF HIGH PRESSURE OVER THE
AREA WHILE NORTHWEST FLOW ALOFT PERSISTS AND BECOMES SOMEWHAT MORE
ZONAL. FORECAST SOUNDINGS SHOW DRYING IN THE MID AND UPPER LEVELS
ALL WHILE SOME TRAPPED SC REMAINS IN THE LOWER LEVELS. THUS WILL
KEEP A DRY FORECAST WITH PLENTY OF CLOUDS AFTER MIDDAY...AND JUST
A FEW LINGERING SNOW SHOWERS DURING THE MORNING. GIVEN THE CLOUD
AND VERY COLD TEMPS WILL TREND HIGHS COOLER THAN MAVMOS AND LOWS
STICK CLOSE ON LOWS AS BY SUNDAY NIGHT SOME WARM AIR ADVECTION
BEGINS AS THE COLD POOL BEGINS TO SLIDE TO THE EAST.
CLOUDS ARE EXPECTED TO INCREASE ON MONDAY AS THE RIDGE SLIDES EAST
AND A SURFACE LOW IS EXPECTED TO PUSH OUT OF THE CENTRAL
MISSISSIPPI RIVER VALLEY INTO THE OHIO VALLEY DURING THE AFTERNOON
AND EVENING. GFS AND NAM ALSO SUGGEST A FAVORABLE ASSOCIATED UPPER
LEVEL SHORT WAVE. PATH OF THE SURFACE LOW PUTS MUCH OF CENTRAL
INDIANA...BUT PARTICULARLY THE NORTHERN AREA...IN A FAVORABLE
PATH FOR ANOTHER ACCUMULATING SNOW. LOWER LEVEL Q VECTOR
CONVERGENCE IS ONCE AGAIN QUITE FAVORABLE...AND FORECAST SOUNDINGS
SHOW DEEP SATURATION BY MONDAY AFTERNOON AND TUESDAY EVENING. 285K
ISENTROPIC SURFACE AGAIN SHOWS GOOD LIFT ON MONDAY AFTERNOON WITH
SPECIFIC HUMDITIES NEAR 3 G/KG. THUS WITH ALL OF THESE FAVORABLE
FACTORS WILL INCREASE POPS ON MONDAY AND MONDAY NIGHT. GIVEN THE
AVAILABLE MOISTURE LIGHT SNOW ACCUMULATIONS OF 2-3 INCHES APPEAR
VERY REASONABLE. AS FOR TEMPS WILL STICK CLOSE TO MAVMOS HIGHS
GIVEN PLENTY OF CLOUDS AMID WAA AND THE ONSET OF SNOW. GIVEN THE
COLD AIR ADVECTION ON THE BACK SIDE OF THE PASSING SURFACE LOW
WILL TREND LOWS COLDER THAN MAVMOS ON MONDAY NIGHT.
IN THE WAKE OF THE DEPARTING LOW...COLD SURFACE HIGH PRESSURE
BUILDS ACROSS THE REGION ON TUESDAY AS WE RETURN TO DRY WEATHER.
FORECAST SOUNDINGS DRY OUT ONCE AGAIN. THUS WILL USE A DRY
FORECAST AND TREND HIGHS COOLER THAN MAVMOS WITH PLENTY OF FRESH
SNOW LINGERING.
&&
.LONG TERM /TUESDAY NIGHT THROUGH SATURDAY/...
ISSUED AT 222 PM EST SAT FEB 2 2013
MODELS ARE CLOSE ENOUGH THAT THE ALLBLEND INITIALIZATION CAN BE
ACCEPTED FOR MOST ITEMS.
TUESDAY NIGHT THROUGH WEDNESDAY NIGHT WILL BE DRY WITH HIGH PRESSURE
MOVING ACROSS THE AREA. THE NEXT SYSTEM MOVES IN FOR THURSDAY
AFTERNOON AND THURSDAY NIGHT. THERE HAS BEEN A WARMING TREND IN THE
MODELS SO MOST PRECIPITATION LOOKS LIKE RAIN ON THURSDAY...WITH
PERHAPS SOME RAIN AND SNOW THURSDAY NIGHT.
DRY WEATHER RETURNS FOR FRIDAY. ANOTHER SYSTEM APPROACHES THE AREA
ON SATURDAY...BUT MOST MODELS KEEP RAIN OUT OF THE AREA BEFORE 00Z.
THUS HAVE REMOVED ALLBLEND/S POPS FOR THEN.
TEMPERATURES WILL BE NEAR NORMAL TO ABOVE NORMAL FOR MUCH OF THE
PERIOD.
&&
.AVIATION /DISCUSSION FOR THE 030300Z IND TAF UPDATE/...
ISSUED AT 920 PM EST SAT FEB 2 2013
BROUGHT IN GUSTS TO 18 KNOTS THROUGH 06Z BASED ON OBSERVATIONAL
TRENDS AND RAP BUFKIT SOUNDINGS. OTHERWISE...MVFR CONTINUES.
PREVIOUS DISCUSSION FOLLOWS...
SURFACE LOW ACROSS SOUTHWESTERN MINNESOTA IS EXPECTED TO DROP
SOUTHEAST AND INTO WEST CENTRAL INDIANA OVERNIGHT WHICH IS EXPECTED
TO RESULT IN ISOLATED SNOW SHOWERS OR FREEZING DRIZZLE. FOR
NOW...WILL STICK WITH FLURRIES AT THE ONSET WITH THE FRONT JUST TO
OUR SOUTH AND PER OBSERVATIONAL TRENDS AND THEN VCSH TOWARDS 12Z FOR
A FEW HOURS WITH THE AFOREMENTION SURFACE WAVE. CONDITIONS SHOULD BE
MVFR THROUGH THE PERIOD BASED ON MODEL TIME SECTIONS AND OBS.
WEST WINDS LESS THAN 10 KNOTS WILL INCREASE TO NEAR 15 KNOTS WITH
GUSTS TO NEAR 25 KNOTS AFTER 15Z.
&&
.IND WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
SYNOPSIS...PUMA
NEAR TERM...TDUD
SHORT TERM...PUMA/TDUD
LONG TERM....50
AVIATION...MK
AREA FORECAST DISCUSSION
NWS NORTHERN INDIANA
100 PM EST FRI FEB 1 2013
.UPDATE...
ONLY MINOR ADJUSTMENTS NEEDED TO WX/POPS AS TRENDS HAVE UNFOLDED
AS EXPECTED. LAKE EFFECT BANDS HAVE QUICKLY SHIFTED NORTH AND ARE
NOW ORIENTED SW-NE ACROSS MUCH OF BERRIEN COUNTY AND EXTREME NW
CASS COUNTY. ADVISORY IN ST JOE AND WARNING IN CASS COUNTY WILL BE
ALLOWED TO EXPIRE WITH RE EVALUATION OF BERRIEN COUNTY WARNING
WITH AFTERNOON PACKAGE.
TEMPERATURES HAVE CLIMBED AOA 10 DEGREES IN ALL BUT A FEW
LOCATIONS. THIS HAS ALSO ALLOWED WIND CHILLS TO "WARM" SOME...AWAY
FROM ADVISORY CRITERIA. AS A RESULT...THE WIND CHILL ADVISORY WILL
ALSO BE ALLOWED TO EXPIRE. WILL NEED TO MAKE SOME CHANGES TO
ACTUAL TEMP TRENDS AS SOME LOCATIONS ALREADY ABOVE FORECASTED
HIGHS. DON`T THINK MUCH MORE OF A RISE WILL OCCUR WITH SC FORMING
IN SEVERAL LOCATIONS THAT WILL SLOW DOWN/STOP ANY ADDITIONAL
CLIMB.
&&
.AVIATION...
MVFR CIGS TO PREVAIL AT BOTH SITES INTO LATE AFTERNOON AS SC DECK
EXPANDS ACROSS THE AREA. WILL NEED TO WATCH TRENDS WITH SOME
POTENTIAL FOR FLURRIES/LGT SNOW SHOWERS REDEVELOPING BUT THINK
OVERALL IMPACT TO TAFS SHOULD BE MINIMAL. LATER TONIGHT...CLIPPER
SYSTEM WILL ARRIVE AND LIGHT SNOW WILL OVERSPREAD THE AREA BETWEEN
8 AND 10Z. HAVE LEFT THE BROAD BRUSHED 2 TO 3 SM AT BOTH SITES
LATER TONIGHT THROUGH18Z WITH MODELS AGREEING ON SNOW LINGERING
UNTIL CLOSE TO THE END OF THE PERIOD. POTENTIAL EXISTS AT BOTH
SITES FOR VSBYS TO DROP TO A MILE OR LESS AT TIMES IN POCKETS OF
HEAVIER SNOWFALL. HOWEVER CONFIDENCE OF PROBS OF IMPACT AT EITHER
SITE LOW SO WILL NOT ADD ANY NEW GROUPS.
&&
.PREV DISCUSSION... /ISSUED 1033 AM EST FRI FEB 1 2013/
UPDATE...
LAKE EFFECT SNOWSHOWERS WERE PERSISTING ACROSS MUCH OF
BERRIEN...WESTERN CASS AND NORTHERN ST JOE (IN) COUNTIES THIS
MORNING. VSBYS HAVE GENERALLY BEEN AROUND A MILE IN THE HEAVIER
BANDS THUS FAR. THE MORE FOCUSED BAND HAS BEEN REPLACED BY A MULTI
BAND CONFIGURATION WHICH WILL PERSIST INTO EARLY AFTERNOON.
NAM12/LOCAL WRF STILL SHIFT THE FLOW MORE SOUTHWESTERLY THIS
AFTERNOON IN ADVANCE OF THE NEXT WAVE. THIS SHOULD ALLOW THE BANDS
TO MIGRATE NORTH AND REFOCUS ACROSS MAINLY NORTHERN BERRIEN
COUNTY. WHILE SOME CONCERN EXISTS EXACTLY WHERE THESE BANDS WILL
ORIENT IN RELATION TO THE CWA...THREAT WARRANTED A EXTENSION OF
SOME OF THE HEADLINES INTO THIS AFTERNOON. THE ADVISORY FOR ST JOE
MICHIGAN WAS ALLOWED TO EXPIRE WITH ACTIVITY REMAINING WEST OF THE
COUNTY. THE LAKE EFFECT SNOW WARNING/ADVISORY WAS EXTENDED THROUGH 18Z
IN CASS AND ST JOE RESPECTIVELY. THE WARNING WAS EXTENDED TO 21Z IN
BERRIEN COUNTY. WILL REEVALUATE HOW THINGS LOOK IN A FEW HOURS.
WIND CHILLS REMAINED IN THE 12 TO 15 BELOW ZERO RANGE ACROSS MOST
LOCATIONS. CLOSE ENOUGH TO ALLOW WIND CHILL ADVISORY TO REMAIN IN
PLACE TILL 18Z.
PREV DISCUSSION... /ISSUED 428 AM EST FRI FEB 1 2013/
.BITTERLY COLD THIS MORNING...
SHORT TERM...
IN FACE OF TREMENDOUS LK TEMP DIFFERENTIALS....LK
RESPONSE SO FAR HAS BEEN QUITE MUTED OWING TO EXTREMELY DRY AIR
ENTRAINMENT OUT OF WI ALG ERN PERIPHERY OF BITTERLY COLD ARCTIC
SFC RIDGE CNTRD OVR THE MO VALLEY AND MSTR VOID ALOFT. WILL HOLD
MOSTLY W/EXISTING HEADLINES BUT DROP ERN EXTENT.
PRIMARY NR TERM CONCERN IS W/INTENSE LL CAA WEDGE DRIVING EWD OUT OF
UPSTREAM ARCTIC HIGH W/IMMEDIATE UPSTREAM AIRMASS NEAR ZERO. 00Z GFS
MADE A SHARP AND NOTABLE DOWNWARD SPIKE IN MAX TEMPS TDA AND LOOKS
TO BE ON TARGET GIVEN CONCURRING RUC TRENDS AND HAVE MADE SIG
DOWNWARD CUTS TO TEMPS TDA/TONIGHT. THUS W/GRADIENT WINDS HOLDING
STRONG A WIND CHILL ADVISORY IS NEEDED AND WILL RUN THROUGH THIS
AFTN W/GUST DRIVEN CHILLS NEARING -20.
COMPLEX BUNDLE OF ENERGY OVR SW CANADA THIS MORNING WILL RACE SEWD
INTO THE WRN OH VALLEY BY SAT AM AS ARCTIC RIDGE BREAKS DOWN EWD
THROUGH THE MID ATL. WRN PORTION OF ERODING ARCTIC BUBBLE SHLD PROVE
TO BE AN EFFICIENT FORCING MECHANISM AS CHANNEL OF INTENSE MID LVL
FLW DVLPS INADV OF APCHG SW TROUGH AND NO DOUBT BORNE OUT IN
ISENTROPIC ANALYSIS. ONLY LAGGARD IS APPROX 6HR DURATION IN
COLLOCATION OF DEEPEST SATURATION AND STRONGEST LIFT LT FRI NIGHT
EARLY SAT WHEN BULK OF SNOWFALL ASSOCD/W LEAD SW FALLS. SECONDARY
IMPULSE QUICK ON THE HEELS OF LEAD WAVE EJECTS THROUGH THE OH VALLEY
SAT NIGHT AND WILL SUSTAIN THE LIGHT SNOW THROUGH SAT AFTN W/PD OF
ENHANCED SNOWFALL LIKELY AGAIN BY SAT EVE.
LONG TERM...
SUNDAY THROUGH THURSDAY...THE CHALLENGES THIS PERIOD INCLUDE THE
TIMING OF SHORT WAVE TROF MOVING THROUGH THE LONG WAVE PATTERN AS
WELL AS A GRADUAL MODERATION LATE IN THIS PERIOD. LAKE EFFECT SNOW
SHOULD BE ONGOING SUNDAY MORNING AS VERY CHILLY AIR SPREADS
SOUTHEAST OVER THE WARMER LAKE WATERS. 850 MB DELTA T VALUES
INCREASE TO AROUND 20...HOWEVER...VERY DRY AIR UPSTREAM WITH A MORE
MARGINAL FETCH SHOULD HELP LIMIT LAKE EFFECT SNOW AMOUNTS. FOR THIS
PACKAGE...WENT WITH SNOW ACCUMULATIONS SUNDAY AROUND 1 INCH...
ALTHOUGH LOCAL AMOUNTS COULD EXCEED 2 INCHES IN HEAVIER BANDS.
INVERSION HEIGHTS WILL FALL SUNDAY NIGHT WITH WINDS BACKING TO THE
WEST...SO LAKE EFFECT SNOW WILL DIMINISH AS A CLIPPER TYPE OF SYSTEM
APPROACHES. FAVOR THE CANADIAN GEM WITH THE MORE NORTHERN TRACK PER
BLAIN/MARTIN CLIPPER CLIMO RESEARCH. KEPT ABOUT A 40 PERCENT CHANCE
FOR SNOW GIVEN UNCERTAINTY IN THE TIMING AND TRACK OF THIS SYSTEM.
THE GARCIA METHOD SUGGESTS THE POTENTIAL FOR 3 TO 5 INCHES OF SNOW
MONDAY WITH THIS SYSTEM IF THE LOW TRACKS SOUTH OF THE FORECAST
AREA. TWO ADDITIONAL SYSTEMS MAY ADD ADDITIONAL SNOW OR A MIX LATER
IN THE WEEK. FOR NOW...LEFT A CHANCE FOR SNOW IN TUESDAY AND AGAIN
ON THURSDAY WITH A RAIN/SNOW MIX POSSIBLE. THE ANALOGS SHOW GOOD
SUPPORT FOR MODERATING TEMPERATURES LATE IN THE WEEK.
&&
.IWX WATCHES/WARNINGS/ADVISORIES...
IN...NONE
MI...LAKE EFFECT SNOW WARNING UNTIL 4 PM EST THIS AFTERNOON FOR
MIZ077.
OH...NONE
LM...SMALL CRAFT ADVISORY UNTIL 5 AM EST SATURDAY FOR LMZ043-046.
&&
$$
SHORT TERM...T
LONG TERM...SKIPPER
AVIATION...FISHER
UPDATE...FISHER
AREA FORECAST DISCUSSION
NWS NORTHERN INDIANA
1033 AM EST FRI FEB 1 2013
.UPDATE...
LAKE EFFECT SNOWSHOWERS WERE PERSISTING ACROSS MUCH OF
BERRIEN...WESTERN CASS AND NORTHERN ST JOE (IN) COUNTIES THIS
MORNING. VSBYS HAVE GENERALLY BEEN AROUND A MILE IN THE HEAVIER
BANDS THUS FAR. THE MORE FOCUSED BAND HAS BEEN REPLACED BY A MULTI
BAND CONFIGURATION WHICH WILL PERSIST INTO EARLY AFTERNOON.
NAM12/LOCAL WRF STILL SHIFT THE FLOW MORE SOUTHWESTERLY THIS
AFTERNOON IN ADVANCE OF THE NEXT WAVE. THIS SHOULD ALLOW THE BANDS
TO MIGRATE NORTH AND REFOCUS ACROSS MAINLY NORTHERN BERRIEN
COUNTY. WHILE SOME CONCERN EXISTS EXACTLY WHERE THESE BANDS WILL
ORIENT IN RELATION TO THE CWA...THREAT WARRANTED A EXTENSION OF
SOME OF THE HEADLINES INTO THIS AFTERNOON. THE ADVISORY FOR ST JOE
MICHIGAN WAS ALLOWED TO EXPIRE WITH ACTIVITY REMAINING WEST OF THE
COUNTY. THE LAKE EFFECT SNOW WARNING/ADVISORY WAS EXTENDED THROUGH 18Z
IN CASS AND ST JOE RESPECTIVELY. THE WARNING WAS EXTENDED TO 21Z IN
BERRIEN COUNTY. WILL REEVALUATE HOW THINGS LOOK IN A FEW HOURS.
WIND CHILLS REMAINED IN THE 12 TO 15 BELOW ZERO RANGE ACROSS MOST
LOCATIONS. CLOSE ENOUGH TO ALLOW WIND CHILL ADVISORY TO REMAIN IN
PLACE TILL 18Z.
&&
.PREV DISCUSSION... /ISSUED 428 AM EST FRI FEB 1 2013/
..BITTERLY COLD THIS MORNING...
SHORT TERM...
IN FACE OF TREMENDOUS LK TEMP DIFFERENTIALS....LK
RESPONSE SO FAR HAS BEEN QUITE MUTED OWING TO EXTREMELY DRY AIR
ENTRAINMENT OUT OF WI ALG ERN PERIPHERY OF BITTERLY COLD ARCTIC
SFC RIDGE CNTRD OVR THE MO VALLEY AND MSTR VOID ALOFT. WILL HOLD
MOSTLY W/EXISTING HEADLINES BUT DROP ERN EXTENT.
PRIMARY NR TERM CONCERN IS W/INTENSE LL CAA WEDGE DRIVING EWD OUT OF
UPSTREAM ARCTIC HIGH W/IMMEDIATE UPSTREAM AIRMASS NEAR ZERO. 00Z GFS
MADE A SHARP AND NOTABLE DOWNWARD SPIKE IN MAX TEMPS TDA AND LOOKS
TO BE ON TARGET GIVEN CONCURRING RUC TRENDS AND HAVE MADE SIG
DOWNWARD CUTS TO TEMPS TDA/TONIGHT. THUS W/GRADIENT WINDS HOLDING
STRONG A WIND CHILL ADVISORY IS NEEDED AND WILL RUN THROUGH THIS
AFTN W/GUST DRIVEN CHILLS NEARING -20.
COMPLEX BUNDLE OF ENERGY OVR SW CANADA THIS MORNING WILL RACE SEWD
INTO THE WRN OH VALLEY BY SAT AM AS ARCTIC RIDGE BREAKS DOWN EWD
THROUGH THE MID ATL. WRN PORTION OF ERODING ARCTIC BUBBLE SHLD PROVE
TO BE AN EFFICIENT FORCING MECHANISM AS CHANNEL OF INTENSE MID LVL
FLW DVLPS INADV OF APCHG SW TROUGH AND NO DOUBT BORNE OUT IN
ISENTROPIC ANALYSIS. ONLY LAGGARD IS APPROX 6HR DURATION IN
COLLOCATION OF DEEPEST SATURATION AND STRONGEST LIFT LT FRI NIGHT
EARLY SAT WHEN BULK OF SNOWFALL ASSOCD/W LEAD SW FALLS. SECONDARY
IMPULSE QUICK ON THE HEELS OF LEAD WAVE EJECTS THROUGH THE OH VALLEY
SAT NIGHT AND WILL SUSTAIN THE LIGHT SNOW THROUGH SAT AFTN W/PD OF
ENHANCED SNOWFALL LIKELY AGAIN BY SAT EVE.
LONG TERM...
SUNDAY THROUGH THURSDAY...THE CHALLENGES THIS PERIOD INCLUDE THE
TIMING OF SHORT WAVE TROF MOVING THROUGH THE LONG WAVE PATTERN AS
WELL AS A GRADUAL MODERATION LATE IN THIS PERIOD. LAKE EFFECT SNOW
SHOULD BE ONGOING SUNDAY MORNING AS VERY CHILLY AIR SPREADS
SOUTHEAST OVER THE WARMER LAKE WATERS. 850 MB DELTA T VALUES
INCREASE TO AROUND 20...HOWEVER...VERY DRY AIR UPSTREAM WITH A MORE
MARGINAL FETCH SHOULD HELP LIMIT LAKE EFFECT SNOW AMOUNTS. FOR THIS
PACKAGE...WENT WITH SNOW ACCUMULATIONS SUNDAY AROUND 1 INCH...
ALTHOUGH LOCAL AMOUNTS COULD EXCEED 2 INCHES IN HEAVIER BANDS.
INVERSION HEIGHTS WILL FALL SUNDAY NIGHT WITH WINDS BACKING TO THE
WEST...SO LAKE EFFECT SNOW WILL DIMINISH AS A CLIPPER TYPE OF SYSTEM
APPROACHES. FAVOR THE CANADIAN GEM WITH THE MORE NORTHERN TRACK PER
BLAIN/MARTIN CLIPPER CLIMO RESEARCH. KEPT ABOUT A 40 PERCENT CHANCE
FOR SNOW GIVEN UNCERTAINTY IN THE TIMING AND TRACK OF THIS SYSTEM.
THE GARCIA METHOD SUGGESTS THE POTENTIAL FOR 3 TO 5 INCHES OF SNOW
MONDAY WITH THIS SYSTEM IF THE LOW TRACKS SOUTH OF THE FORECAST
AREA. TWO ADDITIONAL SYSTEMS MAY ADD ADDITIONAL SNOW OR A MIX LATER
IN THE WEEK. FOR NOW...LEFT A CHANCE FOR SNOW IN TUESDAY AND AGAIN
ON THURSDAY WITH A RAIN/SNOW MIX POSSIBLE. THE ANALOGS SHOW GOOD
SUPPORT FOR MODERATING TEMPERATURES LATE IN THE WEEK.
AVIATION...
OUTSIDE CONTG LK EFFECT VCNTY KSBN TERMINAL FEW CONCERNS AS ARCTIC
WEDGE DEEPENS FURTHER SHRT TERM. THUS OUTSIDE PD OF IFR CONDS IN
-SHSN AT KSBN XPC CONTD DRYING AND BACKING LL WINDS BY MID MORNING
WILL SHIFT WHATS LEFT OF SNOW BANDS NWD INTO SRN MI W/VFR CONDS.
OTRWS STG GRADIENT FLW WILL CONT W/SFC WIND GUSTS AOA 20KTS
THROUGH THIS MORNING.
&&
.IWX WATCHES/WARNINGS/ADVISORIES...
IN...WIND CHILL ADVISORY UNTIL 1 PM EST /NOON CST/ THIS AFTERNOON FOR
INZ003>006-008-009-012>018-020-022>027-032>034.
LAKE EFFECT SNOW ADVISORY UNTIL 1 PM EST THIS AFTERNOON FOR
INZ004.
MI...LAKE EFFECT SNOW WARNING UNTIL 4 PM EST THIS AFTERNOON FOR
MIZ077.
LAKE EFFECT SNOW WARNING UNTIL 1 PM EST THIS AFTERNOON FOR
MIZ078.
OH...WIND CHILL ADVISORY UNTIL 1 PM EST THIS AFTERNOON FOR OHZ015-016-
024-025.
LM...SMALL CRAFT ADVISORY UNTIL 5 AM EST SATURDAY FOR LMZ043-046.
&&
$$
SHORT TERM...T
LONG TERM...SKIPPER
AVIATION...T
UPDATE...FISHER
AREA FORECAST DISCUSSION
NWS INDIANAPOLIS IN
1008 AM EST FRI FEB 1 2013
.UPDATE...
THE NEAR TERM SECTION HAS BEEN UPDATED BELOW
&&
.SYNOPSIS...
ISSUED AT 323 AM EST FRI FEB 1 2013
A SERIES OF UPPER DISTURBANCES WITHIN A NORTHWESTERLY FLOW WILL
RESULT IN PERIODIC CHANCES FOR PRECIPITATION INTO EARLY NEXT WEEK.
HIGH PRESSURE IS EXPECTED DURING THE MIDDLE PARTS OF NEXT WEEK. A
FRONTAL SYSTEM MAY APPROACH THE AREA TOWARDS NEXT THURSDAY.
&&
.NEAR TERM /THIS AFTERNOON/...
ISSUED AT 942 AM EST FRI FEB 1 2013
HIGH PRESSURE OVER THE CENTRAL MISSISSIPPI RIVER VALLEY WAS
BUILDING ACROSS THE OHIO VALLEY LATE THIS MORNING. SURFACE
ANALYSIS SHOWS GOOD PRESSURE GRADIENT ACROSS CENTRAL INDIANA AND
WINDS REMAINED RATHER GUSTY THIS MORNING. WIND CHILL VALUES
CONTINUE TO TOUCH WIND CHILL ADVISORY LEVELS AT TIMES...BUT WITH
DAYTIME HEATING EXPECTED VALUES TO RISE ABOVE ADVISORY LEVELS IN
THE NEXT HOUR AND WILL HOLD ON TO ADVISORY UNTIL THEN.
&&
.SHORT TERM /TONIGHT THROUGH SUNDAY/...
ISSUED AT 323 AM EST FRI FEB 1 2013
MODELS INDICATE THE MAIN ITEM OF INTEREST DURING THIS PERIOD WILL BE
A DISTURBANCE THAT IS EXPECTED TO DROP SOUTHEAST INTO THE AREA ON
SATURDAY. LIFT ASSOCIATED WITH THIS DISTURBANCE LOOKS DECENT THROUGH
THE PRECIPITATION BEARING LAYER...BUT NOT OVERLY IMPRESSIVE. APPEARS
FROM THE MODEL DATA THAT THE MAIN LIFT WILL BE MOVING INTO THE AREA
ROUGHLY 020600Z-021800Z...SO WILL GO WITH LIKELY POPS FOR SNOW AFTER
MIDNIGHT TONIGHT THROUGH THE EARLY AFTERNOON HOURS ON SATURDAY.
STILL APPEARS A COUPLE OF INCHES ACCUMULATION IS LIKELY FROM THIS
SYSTEM.
MODELS SUGGEST THERE STILL MAY BE SOME UPPER ENERGY MOVING THROUGH
THE AREA SATURDAY NIGHT...SO WILL KEEP SOME CHANCE POPS GOING AT
THAT TIME. MOST OF THE OPERATIONAL AND ENSEMBLE DATA SUGGEST
PRECIPITATION THREAT WILL BE OVER BY SUNDAY...SO WILL GO DRY AT THAT
TIME.
PROGGED LOW LEVEL THICKNESSES SUGGEST THE GFS MOS TEMPERATURES
GUIDANCE LOOKS TOO COLD THROUGHOUT MOST OF THE PERIOD. WILL LEAN
TOWARDS THE WARMER NAM GUIDANCE.
&&
.LONG TERM /MONDAY THROUGH FRIDAY/...
ISSUED AT 323 AM EST FRI FEB 1 2013
ENSEMBLES SEEM TO BE IN AGREEMENT WITH THE LARGE SCALE DETAILS OF
THE EXTENDED PERIOD AND THE ALLBLEND INITIALIZATION SEEMS REASONABLE
BASED ON THIS OUTPUT. THIS PERIOD WILL BE CHARACTERIZED BY A COUPLE
WEAK SYSTEMS ROTATING THROUGH A BROAD UPPER TROUGH...BRINGING
PERIODIC CHANCES FOR PRECIPITATION TO CENTRAL INDIANA THROUGH LATE
NEXT WORK WEEK.
FIRST SYSTEM MOVES THROUGH ON MONDAY/MONDAY NIGHT AND SHOULD BE COLD
ENOUGH TO PRODUCE ONLY LOW CHANCES FOR SNOW. ANOTHER QUICK SYSTEM
DIVES THROUGH THE AREA AGAIN ON TUESDAY AND PRODUCES CHANCE FOR SNOW
ACROSS THE NORTH AND A RAIN/SNOW MIX (SOUTH). VERY LIGHT PRECIP
AMOUNTS WITH BOTH FEATURES. NEXT SYSTEM MOVES THROUGH THU/THU NIGHT
AND ATTM COULD BRING A FAIR AMOUNT OF MOISTURE TO THE REGION AS
COMPARED TO THE LAST FEW DISTURBANCES...BUT THIS IS STILL VERY FAR
OUT IN THE FORECAST. GOOD ENOUGH FOR CHANCE POPS DURING THIS TIME
WITH PRECIP TYPE RANGING FROM ALL SNOW ACROSS THE NORTH TO A
RAIN/SNOW MIX SOUTH.
&&
.AVIATION /DISCUSSION FOR THE 011500Z TAF UPDATE/...
ISSUED AT 906 AM EST FRI FEB 1 2013
MAIN AREA OF MVFR CEILINGS HAS BROKEN UP LEAVING BEHIND JUST PATCHY
MVFR CEILINGS. THUS HAVE CHANGED CEILINGS TO SCATTERED TEMPO BROKEN
FOR THE FIRST COUPLE OF HOURS. IT NOW APPEARS THAT VFR CONDITIONS
WILL BE PREDOMINANT FROM LATE MORNING ON.
PREVIOUS DISCUSSION FOLLOWS...
CONTRARY TO ALL EARLIER GUIDANCE THE PESKY SNOW SHOWERS OR
FLURRIES PERSIST ACROSS THE FORECAST AREA. BELIEVE HRRR HANDLES
THIS FEATURE BEST WITH HOLDING ONTO THIS ACTIVITY OVER CENTRAL
INDIANA UNTIL LATE THIS MORNING/EARLY AFTERNOON...POSSIBLY
IMPACTING TERMINALS SUCH AS KIND AND KBMG. THIS HAS BEEN INDICATED
IN THE TAFS. ALSO...MFVR CEILINGS WILL HANG ON AWHILE LONGER...FOR
MUCH OF THE DAY FOR KIND AND KBMG...BUT RISE TO OVERCAST VFR AT
THE WESTERN TAFS KLAF AND KHUF. (LATEST MAV GUIDANCE HAS CAUGHT
AHOLD OF THIS TREND.) THIS VFR WILL BE SHORT LIVED HOWEVER AS THE
AREA IS SET TO BE IMPACTED BY NEXT CLIPPER SYSTEM WILL BEGIN LATER
TONIGHT AND CONTINUE THROUGH SATURDAY...WITH CONDITIONS
DETERIORATING TO MFVR OVERNIGHT AND POSSIBLY IFR BY EARLY SATURDAY
MORNING. FOR NOW PUT IN CEILINGS AROUND 1K FT. LATER ISSUANCES MAY
GET A BETTER HANDLE ON THIS AND LOWER TO IFR.
&&
.IND WATCHES/WARNINGS/ADVISORIES...
WIND CHILL ADVISORY UNTIL 11 AM EST THIS MORNING FOR INZ021-
028>031-035>049.
&&
$$
SYNOPSIS...JAS
NEAR TERM...PUMA
SHORT TERM...JAS
LONG TERM....SMF
AVIATION...SMF/50
AREA FORECAST DISCUSSION
NWS INDIANAPOLIS IN
906 AM EST FRI FEB 1 2013
.UPDATE...
THE AVIATION SECTION HAS BEEN UPDATED BELOW.
&&
.SYNOPSIS...
ISSUED AT 323 AM EST FRI FEB 1 2013
A SERIES OF UPPER DISTURBANCES WITHIN A NORTHWESTERLY FLOW WILL
RESULT IN PERIODIC CHANCES FOR PRECIPITATION INTO EARLY NEXT WEEK.
HIGH PRESSURE IS EXPECTED DURING THE MIDDLE PARTS OF NEXT WEEK. A
FRONTAL SYSTEM MAY APPROACH THE AREA TOWARDS NEXT THURSDAY.
&&
.NEAR TERM /TODAY/...
ISSUED AT 323 AM EST FRI FEB 1 2013
WILL BE ISSUING A WIND CHILL ADVISORY FOR AREAS ROUGHLY NORTH OF
INTERSTATE 70 UNTIL 011600Z AS IT APPEARS EXPECTED TEMPERATURES AND
WINDS THROUGH LATE MORNING WILL RESULT IN WIND CHILLS AROUND
ADVISORY CRITERIA. WINDS SHOULD BEGIN TO SLACKEN OFF TOWARDS MIDDAY
AS PRESSURE GRADIENT AND COLD ADVECTION DIMINISH...SO EXPECTING WIND
CHILLS TO IMPROVE BY THEN.
OTHERWISE...LOW LEVEL LAPSE RATES REMAIN STEEP UNDER STRONG COLD
ADVECTION THIS MORNING...SO WILL KEEP SOME FLURRIES IN THE FORECAST
THROUGH THE LATE MORNING. SHOULD SEE A DECREASING TREND IN CLOUD
COVER DURING THE DAY AS COLD ADVECTION/LOW LEVEL LAPSE RATES
DIMINISH LATER TODAY.
BASED ON PROGGED LOW LEVEL THICKNESSES TODAY...WILL TAKE ABOUT 3
DEGREES OFF THE NAM MOS GUIDANCE.
&&
.SHORT TERM /TONIGHT THROUGH SUNDAY/...
ISSUED AT 323 AM EST FRI FEB 1 2013
MODELS INDICATE THE MAIN ITEM OF INTEREST DURING THIS PERIOD WILL BE
A DISTURBANCE THAT IS EXPECTED TO DROP SOUTHEAST INTO THE AREA ON
SATURDAY. LIFT ASSOCIATED WITH THIS DISTURBANCE LOOKS DECENT THROUGH
THE PRECIPITATION BEARING LAYER...BUT NOT OVERLY IMPRESSIVE. APPEARS
FROM THE MODEL DATA THAT THE MAIN LIFT WILL BE MOVING INTO THE AREA
ROUGHLY 020600Z-021800Z...SO WILL GO WITH LIKELY POPS FOR SNOW AFTER
MIDNIGHT TONIGHT THROUGH THE EARLY AFTERNOON HOURS ON SATURDAY.
STILL APPEARS A COUPLE OF INCHES ACCUMULATION IS LIKELY FROM THIS
SYSTEM.
MODELS SUGGEST THERE STILL MAY BE SOME UPPER ENERGY MOVING THROUGH
THE AREA SATURDAY NIGHT...SO WILL KEEP SOME CHANCE POPS GOING AT
THAT TIME. MOST OF THE OPERATIONAL AND ENSEMBLE DATA SUGGEST
PRECIPITATION THREAT WILL BE OVER BY SUNDAY...SO WILL GO DRY AT THAT
TIME.
PROGGED LOW LEVEL THICKNESSES SUGGEST THE GFS MOS TEMPERATURES
GUIDANCE LOOKS TOO COLD THROUGHOUT MOST OF THE PERIOD. WILL LEAN
TOWARDS THE WARMER NAM GUIDANCE.
&&
.LONG TERM /MONDAY THROUGH FRIDAY/...
ISSUED AT 323 AM EST FRI FEB 1 2013
ENSEMBLES SEEM TO BE IN AGREEMENT WITH THE LARGE SCALE DETAILS OF
THE EXTENDED PERIOD AND THE ALLBLEND INITIALIZATION SEEMS REASONABLE
BASED ON THIS OUTPUT. THIS PERIOD WILL BE CHARACTERIZED BY A COUPLE
WEAK SYSTEMS ROTATING THROUGH A BROAD UPPER TROUGH...BRINGING
PERIODIC CHANCES FOR PRECIPITATION TO CENTRAL INDIANA THROUGH LATE
NEXT WORK WEEK.
FIRST SYSTEM MOVES THROUGH ON MONDAY/MONDAY NIGHT AND SHOULD BE COLD
ENOUGH TO PRODUCE ONLY LOW CHANCES FOR SNOW. ANOTHER QUICK SYSTEM
DIVES THROUGH THE AREA AGAIN ON TUESDAY AND PRODUCES CHANCE FOR SNOW
ACROSS THE NORTH AND A RAIN/SNOW MIX (SOUTH). VERY LIGHT PRECIP
AMOUNTS WITH BOTH FEATURES. NEXT SYSTEM MOVES THROUGH THU/THU NIGHT
AND ATTM COULD BRING A FAIR AMOUNT OF MOISTURE TO THE REGION AS
COMPARED TO THE LAST FEW DISTURBANCES...BUT THIS IS STILL VERY FAR
OUT IN THE FORECAST. GOOD ENOUGH FOR CHANCE POPS DURING THIS TIME
WITH PRECIP TYPE RANGING FROM ALL SNOW ACROSS THE NORTH TO A
RAIN/SNOW MIX SOUTH.
&&
.AVIATION /DISCUSSION FOR THE 011500Z TAF UPDATE/...
ISSUED AT 906 AM EST FRI FEB 1 2013
MAIN AREA OF MVFR CEILINGS HAS BROKEN UP LEAVING BEHIND JUST PATCHY
MVFR CEILINGS. THUS HAVE CHANGED CEILINGS TO SCATTERED TEMPO BROKEN
FOR THE FIRST COUPLE OF HOURS. IT NOW APPEARS THAT VFR CONDITIONS
WILL BE PREDOMINANT FROM LATE MORNING ON.
PREVIOUS DISCUSSION FOLLOWS...
CONTRARY TO ALL EARLIER GUIDANCE THE PESKY SNOW SHOWERS OR
FLURRIES PERSIST ACROSS THE FORECAST AREA. BELIEVE HRRR HANDLES
THIS FEATURE BEST WITH HOLDING ONTO THIS ACTIVITY OVER CENTRAL
INDIANA UNTIL LATE THIS MORNING/EARLY AFTERNOON...POSSIBLY
IMPACTING TERMINALS SUCH AS KIND AND KBMG. THIS HAS BEEN INDICATED
IN THE TAFS. ALSO...MFVR CEILINGS WILL HANG ON AWHILE LONGER...FOR
MUCH OF THE DAY FOR KIND AND KBMG...BUT RISE TO OVERCAST VFR AT
THE WESTERN TAFS KLAF AND KHUF. (LATEST MAV GUIDANCE HAS CAUGHT
AHOLD OF THIS TREND.) THIS VFR WILL BE SHORT LIVED HOWEVER AS THE
AREA IS SET TO BE IMPACTED BY NEXT CLIPPER SYSTEM WILL BEGIN LATER
TONIGHT AND CONTINUE THROUGH SATURDAY...WITH CONDITIONS
DETERIORATING TO MFVR OVERNIGHT AND POSSIBLY IFR BY EARLY SATURDAY
MORNING. FOR NOW PUT IN CEILINGS AROUND 1K FT. LATER ISSUANCES MAY
GET A BETTER HANDLE ON THIS AND LOWER TO IFR.
&&
.IND WATCHES/WARNINGS/ADVISORIES...
WIND CHILL ADVISORY UNTIL 11 AM EST THIS MORNING FOR INZ021-
028>031-035>049.
&&
$$
SYNOPSIS...JAS
NEAR TERM...JAS
SHORT TERM...JAS
LONG TERM....SMF
AVIATION...SMF/50
AREA FORECAST DISCUSSION
NWS INDIANAPOLIS IN
536 AM EST FRI FEB 1 2013
.UPDATE...
THE AVIATION SECTION HAS BEEN UPDATED BELOW.
&&
.SYNOPSIS...
ISSUED AT 323 AM EST FRI FEB 1 2013
A SERIES OF UPPER DISTURBANCES WITHIN A NORTHWESTERLY FLOW WILL
RESULT IN PERIODIC CHANCES FOR PRECIPITATION INTO EARLY NEXT WEEK.
HIGH PRESSURE IS EXPECTED DURING THE MIDDLE PARTS OF NEXT WEEK. A
FRONTAL SYSTEM MAY APPROACH THE AREA TOWARDS NEXT THURSDAY.
&&
.NEAR TERM /TODAY/...
ISSUED AT 323 AM EST FRI FEB 1 2013
WILL BE ISSUING A WIND CHILL ADVISORY FOR AREAS ROUGHLY NORTH OF
INTERSTATE 70 UNTIL 011600Z AS IT APPEARS EXPECTED TEMPERATURES AND
WINDS THROUGH LATE MORNING WILL RESULT IN WIND CHILLS AROUND
ADVISORY CRITERIA. WINDS SHOULD BEGIN TO SLACKEN OFF TOWARDS MIDDAY
AS PRESSURE GRADIENT AND COLD ADVECTION DIMINISH...SO EXPECTING WIND
CHILLS TO IMPROVE BY THEN.
OTHERWISE...LOW LEVEL LAPSE RATES REMAIN STEEP UNDER STRONG COLD
ADVECTION THIS MORNING...SO WILL KEEP SOME FLURRIES IN THE FORECAST
THROUGH THE LATE MORNING. SHOULD SEE A DECREASING TREND IN CLOUD
COVER DURING THE DAY AS COLD ADVECTION/LOW LEVEL LAPSE RATES
DIMINISH LATER TODAY.
BASED ON PROGGED LOW LEVEL THICKNESSES TODAY...WILL TAKE ABOUT 3
DEGREES OFF THE NAM MOS GUIDANCE.
&&
.SHORT TERM /TONIGHT THROUGH SUNDAY/...
ISSUED AT 323 AM EST FRI FEB 1 2013
MODELS INDICATE THE MAIN ITEM OF INTEREST DURING THIS PERIOD WILL BE
A DISTURBANCE THAT IS EXPECTED TO DROP SOUTHEAST INTO THE AREA ON
SATURDAY. LIFT ASSOCIATED WITH THIS DISTURBANCE LOOKS DECENT THROUGH
THE PRECIPITATION BEARING LAYER...BUT NOT OVERLY IMPRESSIVE. APPEARS
FROM THE MODEL DATA THAT THE MAIN LIFT WILL BE MOVING INTO THE AREA
ROUGHLY 020600Z-021800Z...SO WILL GO WITH LIKELY POPS FOR SNOW AFTER
MIDNIGHT TONIGHT THROUGH THE EARLY AFTERNOON HOURS ON SATURDAY.
STILL APPEARS A COUPLE OF INCHES ACCUMULATION IS LIKELY FROM THIS
SYSTEM.
MODELS SUGGEST THERE STILL MAY BE SOME UPPER ENERGY MOVING THROUGH
THE AREA SATURDAY NIGHT...SO WILL KEEP SOME CHANCE POPS GOING AT
THAT TIME. MOST OF THE OPERATIONAL AND ENSEMBLE DATA SUGGEST
PRECIPITATION THREAT WILL BE OVER BY SUNDAY...SO WILL GO DRY AT THAT
TIME.
PROGGED LOW LEVEL THICKNESSES SUGGEST THE GFS MOS TEMPERATURES
GUIDANCE LOOKS TOO COLD THROUGHOUT MOST OF THE PERIOD. WILL LEAN
TOWARDS THE WARMER NAM GUIDANCE.
&&
.LONG TERM /MONDAY THROUGH FRIDAY/...
ISSUED AT 323 AM EST FRI FEB 1 2013
ENSEMBLES SEEM TO BE IN AGREEMENT WITH THE LARGE SCALE DETAILS OF
THE EXTENDED PERIOD AND THE ALLBLEND INITIALIZATION SEEMS REASONABLE
BASED ON THIS OUTPUT. THIS PERIOD WILL BE CHARACTERIZED BY A COUPLE
WEAK SYSTEMS ROTATING THROUGH A BROAD UPPER TROUGH...BRINGING
PERIODIC CHANCES FOR PRECIPITATION TO CENTRAL INDIANA THROUGH LATE
NEXT WORK WEEK.
FIRST SYSTEM MOVES THROUGH ON MONDAY/MONDAY NIGHT AND SHOULD BE COLD
ENOUGH TO PRODUCE ONLY LOW CHANCES FOR SNOW. ANOTHER QUICK SYSTEM
DIVES THROUGH THE AREA AGAIN ON TUESDAY AND PRODUCES CHANCE FOR SNOW
ACROSS THE NORTH AND A RAIN/SNOW MIX (SOUTH). VERY LIGHT PRECIP
AMOUNTS WITH BOTH FEATURES. NEXT SYSTEM MOVES THROUGH THU/THU NIGHT
AND ATTM COULD BRING A FAIR AMOUNT OF MOISTURE TO THE REGION AS
COMPARED TO THE LAST FEW DISTURBANCES...BUT THIS IS STILL VERY FAR
OUT IN THE FORECAST. GOOD ENOUGH FOR CHANCE POPS DURING THIS TIME
WITH PRECIP TYPE RANGING FROM ALL SNOW ACROSS THE NORTH TO A
RAIN/SNOW MIX SOUTH.
&&
.AVIATION /DISCUSSION FOR THE 011200Z TAF ISSUANCE/...
ISSUED AT 528 AM EST FRI FEB 1 2013
CONTRARY TO ALL EARLIER GUIDANCE THE PESKY SNOW SHOWERS OR
FLURRIES PERSIST ACROSS THE FORECAST AREA. BELIEVE HRRR HANDLES
THIS FEATURE BEST WITH HOLDING ONTO THIS ACTIVITY OVER CENTRAL
INDIANA UNTIL LATE THIS MORNING/EARLY AFTERNOON...POSSIBLY
IMPACTING TERMINALS SUCH AS KIND AND KBMG. THIS HAS BEEN INDICATED
IN THE TAFS. ALSO...MFVR CEILINGS WILL HANG ON AWHILE LONGER...FOR
MUCH OF THE DAY FOR KIND AND KBMG...BUT RISE TO OVERCAST VFR AT
THE WESTERN TAFS KLAF AND KHUF. (LATEST MAV GUIDANCE HAS CAUGHT
AHOLD OF THIS TREND.) THIS VFR WILL BE SHORT LIVED HOWEVER AS THE
AREA IS SET TO BE IMPACTED BY NEXT CLIPPER SYSTEM WILL BEGIN LATER
TONIGHT AND CONTINUE THROUGH SATURDAY...WITH CONDITIONS
DETERIORATING TO MFVR OVERNIGHT AND POSSIBLY IFR BY EARLY SATURDAY
MORNING. FOR NOW PUT IN CEILINGS AROUND 1K FT. LATER ISSUANCES MAY
GET A BETTER HANDLE ON THIS AND LOWER TO IFR.
&&
.IND WATCHES/WARNINGS/ADVISORIES...
WIND CHILL ADVISORY UNTIL 11 AM EST THIS MORNING FOR INZ021-
028>031-035>049.
&&
$$
SYNOPSIS...JAS
NEAR TERM...JAS
SHORT TERM...JAS
LONG TERM....SMF
AVIATION...SMF
AREA FORECAST DISCUSSION
NWS NORTHERN INDIANA
428 AM EST FRI FEB 1 2013
...BITTERLY COLD THIS MORNING...
.SHORT TERM...
IN FACE OF TREMENDOUS LK TEMP DIFFERENTIALS....LK
RESPONSE SO FAR HAS BEEN QUITE MUTED OWING TO EXTREMELY DRY AIR
ENTRAINMENT OUT OF WI ALG ERN PERIPHERY OF BITTERLY COLD ARCTIC
SFC RIDGE CNTRD OVR THE MO VALLEY AND MSTR VOID ALOFT. WILL HOLD
MOSTLY W/EXISTING HEADLINES BUT DROP ERN EXTENT.
PRIMARY NR TERM CONCERN IS W/INTENSE LL CAA WEDGE DRIVING EWD OUT OF
UPSTREAM ARCTIC HIGH W/IMMEDIATE UPSTREAM AIRMASS NEAR ZERO. 00Z GFS
MADE A SHARP AND NOTABLE DOWNWARD SPIKE IN MAX TEMPS TDA AND LOOKS
TO BE ON TARGET GIVEN CONCURRING RUC TRENDS AND HAVE MADE SIG
DOWNWARD CUTS TO TEMPS TDA/TONIGHT. THUS W/GRADIENT WINDS HOLDING
STRONG A WIND CHILL ADVISORY IS NEEDED AND WILL RUN THROUGH THIS
AFTN W/GUST DRIVEN CHILLS NEARING -20.
COMPLEX BUNDLE OF ENERGY OVR SW CANADA THIS MORNING WILL RACE SEWD
INTO THE WRN OH VALLEY BY SAT AM AS ARCTIC RIDGE BREAKS DOWN EWD
THROUGH THE MID ATL. WRN PORTION OF ERODING ARCTIC BUBBLE SHLD PROVE
TO BE AN EFFICIENT FORCING MECHANISM AS CHANNEL OF INTENSE MID LVL
FLW DVLPS INADV OF APCHG SW TROUGH AND NO DOUBT BORNE OUT IN
ISENTROPIC ANALYSIS. ONLY LAGGARD IS APPROX 6HR DURATION IN
COLLOCATION OF DEEPEST SATURATION AND STRONGEST LIFT LT FRI NIGHT
EARLY SAT WHEN BULK OF SNOWFALL ASSOCD/W LEAD SW FALLS. SECONDARY
IMPULSE QUICK ON THE HEELS OF LEAD WAVE EJECTS THROUGH THE OH VALLEY
SAT NIGHT AND WILL SUSTAIN THE LIGHT SNOW THROUGH SAT AFTN W/PD OF
ENHANCED SNOWFALL LIKELY AGAIN BY SAT EVE.
&&
.LONG TERM...
SUNDAY THROUGH THURSDAY...THE CHALLENGES THIS PERIOD INCLUDE THE
TIMING OF SHORT WAVE TROF MOVING THROUGH THE LONG WAVE PATTERN AS
WELL AS A GRADUAL MODERATION LATE IN THIS PERIOD. LAKE EFFECT SNOW
SHOULD BE ONGOING SUNDAY MORNING AS VERY CHILLY AIR SPREADS
SOUTHEAST OVER THE WARMER LAKE WATERS. 850 MB DELTA T VALUES
INCREASE TO AROUND 20...HOWEVER...VERY DRY AIR UPSTREAM WITH A MORE
MARGINAL FETCH SHOULD HELP LIMIT LAKE EFFECT SNOW AMOUNTS. FOR THIS
PACKAGE...WENT WITH SNOW ACCUMULATIONS SUNDAY AROUND 1 INCH...
ALTHOUGH LOCAL AMOUNTS COULD EXCEED 2 INCHES IN HEAVIER BANDS.
INVERSION HEIGHTS WILL FALL SUNDAY NIGHT WITH WINDS BACKING TO THE
WEST...SO LAKE EFFECT SNOW WILL DIMINISH AS A CLIPPER TYPE OF SYSTEM
APPROACHES. FAVOR THE CANADIAN GEM WITH THE MORE NORTHERN TRACK PER
BLAIN/MARTIN CLIPPER CLIMO RESEARCH. KEPT ABOUT A 40 PERCENT CHANCE
FOR SNOW GIVEN UNCERTAINTY IN THE TIMING AND TRACK OF THIS SYSTEM.
THE GARCIA METHOD SUGGESTS THE POTENTIAL FOR 3 TO 5 INCHES OF SNOW
MONDAY WITH THIS SYSTEM IF THE LOW TRACKS SOUTH OF THE FORECAST
AREA. TWO ADDITIONAL SYSTEMS MAY ADD ADDITIONAL SNOW OR A MIX LATER
IN THE WEEK. FOR NOW...LEFT A CHANCE FOR SNOW IN TUESDAY AND AGAIN
ON THURSDAY WITH A RAIN/SNOW MIX POSSIBLE. THE ANALOGS SHOW GOOD
SUPPORT FOR MODERATING TEMPERATURES LATE IN THE WEEK.
&&
.AVIATION...
OUTSIDE CONTG LK EFFECT VCNTY KSBN TERMINAL FEW CONCERNS AS ARCTIC
WEDGE DEEPENS FURTHER SHRT TERM. THUS OUTSIDE PD OF IFR CONDS IN
-SHSN AT KSBN XPC CONTD DRYING AND BACKING LL WINDS BY MID MORNING
WILL SHIFT WHATS LEFT OF SNOW BANDS NWD INTO SRN MI W/VFR CONDS.
OTRWS STG GRADIENT FLW WILL CONT W/SFC WIND GUSTS AOA 20KTS
THROUGH THIS MORNING.
&&
.IWX WATCHES/WARNINGS/ADVISORIES...
IN...WIND CHILL ADVISORY UNTIL 1 PM EST /NOON CST/ THIS AFTERNOON FOR
INZ003>006-008-009-012>018-020-022>027-032>034.
LAKE EFFECT SNOW ADVISORY UNTIL 10 AM EST THIS MORNING FOR
INZ004.
MI...LAKE EFFECT SNOW ADVISORY UNTIL 10 AM EST THIS MORNING FOR
MIZ079.
LAKE EFFECT SNOW WARNING UNTIL 10 AM EST THIS MORNING FOR MIZ077-
078.
OH...WIND CHILL ADVISORY UNTIL 1 PM EST THIS AFTERNOON FOR OHZ015-016-
024-025.
LM...SMALL CRAFT ADVISORY UNTIL 5 AM EST SATURDAY FOR LMZ043-046.
&&
$$
SHORT TERM...T
LONG TERM...SKIPPER
AVIATION...T
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
652 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 00Z TAFS THROUGH 00Z SUNDAY EVENING)
ISSUED AT 652 PM EST SAT FEB 2 2013
AT KCMX...MVFR CIGS WILL LIKELY SCATTER OUT THIS EVENING AS WINDS
SHIFT TO THE SW...CUTTING OFF LAKE EFFECT CLOUDS. AS ANOTHER UPPER
LEVEL DISTURBANCE/SFC TROF APPROACH OVERNIGHT...MORE -SN/MVFR
CONDITIONS WILL PREDOMINATE AFTER 06Z. AS THE TROF PASSES TOWARD
12Z...EXPECT A PERIOD OF MDT/HVY SHSN WITH LIFR CONDITIONS FOR AT
LEAST A COUPLE OF HRS. FOLLOWING THE PASSAGE OF THE TROF/HEAVIER
SHSN...LIFR CONDITIONS WILL THEN LINGER THRU THE REST OF THE FCST
PERIOD AS LAKE EFFECT SHSN/SMALL SNOW FLAKES/SOME BLSN EFFECTIVELY
REDUCE VIS.
AT KIWD...VFR CONDITIONS THRU THE EVENING WILL GIVE WAY TO SOME
-SN/MVFR CONDITIONS LATE TONIGHT WITH APPROACH OF DISTURBANCE/LOW
PRES TROF. IFR CONDITIONS WILL ACCOMPANY THE PASSAGE OF THE TROF AND
THEN PERSIST AS LAKE EFFECT SHSN SET UP UNDER NW WINDS BEHIND TROF.
WINDS MAY BEGIN TO BACK JUST ENOUGH LATER IN THE AFTN FOR CONDITIONS
TO IMPROVE TO MVFR.
AT KSAW...EXPECT VFR CONDITIONS TO PREVAIL TONIGHT WITH LIGHT W TO
SW DOWNSLOPE WINDS AHEAD OF APPROACHING LOW PRES TROF. MVFR CIGS AND
FLURRIES SHOULD ARRIVE FOLLOWING THE PASSAGE OF TROF SUN MORNING 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...ROLFSON
MARINE...KC/JLA
AREA FORECAST DISCUSSION
NWS GRAND RAPIDS MI
1247 PM EST FRI FEB 1 2013
.SYNOPSIS...
ISSUED AT 339 AM EST FRI FEB 1 2013
AFTER MORNING SNOWS TODAY...THE SNOW SHOWERS ARE EXPECTED TO DIMINISH
SOMEWHAT THIS AFTERNOON. HOWEVER THE SNOW IS EXPECTED TO INCREASE
IN COVERAGE AND INTENSITY ONCE AGAIN BY THIS EVENING. SEVERAL
INCHES OF SNOW WILL BE POSSIBLE AGAIN TONIGHT...ESPECIALLY WEST OF
U.S. 131 AND NORTH OF HOLLAND. THE SNOW INTENSITY WILL BE HEAVY
ENOUGH TO OCCASIONALLY PRODUCE NEAR WHITEOUT CONDITIONS.
MEANWHILE INLAND AREAS SHOULD ALSO SEE SNOWFALL TONIGHT...WITH
SOMEWHAT LESS ACCUMULATION.
THE SNOW INTENSITY AND COVERAGE IS EXPECTED TO DIMINISH BY
SATURDAY AFTERNOON. THEN ANOTHER WEAKER SYSTEM MOVES IN FOR SUNDAY
MORNING...LIKELY PRODUCING MORE ACCUMULATING SNOW.
&&
.UPDATE...
ISSUED AT 658 AM EST FRI FEB 1 2013
BASED ON THE LATEST RADAR LOOPS IN CONJUNCTION WITH THE LATEST HRRR
AND RAP DATA.... I INCREASED THE POP CONDITIONAL NEAR AND WEST OF
US-131 THROUGH LATE MORNING. BOUNDARY LAYER WINDS BECOME MORE
WESTERLY DURING THE DAY TODAY SO THE SNOW BANDS WILL BECOME MORE
EAST / WEST. I DO EXPECT AN INCH OR TWO BETWEEN NOW AND NOON SOUTH
OF MUSKEGON AND WEST OF GRAND RAPIDS.
DAY TIME HEATING WILL HELP TO SPREAD THE SNOW SHOWERS INLAND BUT
THE INTENSITY SHOULD BE NOT MUCH MORE THAN FLURRIES EAST OF
US-131. I INCREASED POP THERE TOO SINCE MORE THAN LIKELY THERE
WILL BE SOME SNOW SHOWERS EVEN IF THEY ARE LIGHT.
&&
.SHORT TERM...(TODAY THROUGH SUNDAY)
ISSUED AT 339 AM EST FRI FEB 1 2013
WILL ADJUST HEADLINES FOR THIS LONG DURATION EVENT.
WE WILL CONTINUE TO SEE FAIRLY INTENSE SNOW SHOWERS THIS MORNING
AS INVERSION HEIGHTS REMAIN HIGH AND THERE REMAINS LIFT WITHIN THE
DGZ. HOWEVER TOWARD MID DAY THE INVERSION HEIGHTS LOWER AND THERE
WILL BE LESS LIFT AS A SHORT WAVE EXITS THE REGION. THIS LULL WILL
PROBABLY ONLY LAST 6 TO 8 HOURS...SO NOT REALLY LONG ENOUGH TO
CALL THE EVENT OVER...AS THE SNOW WILL CONTINUE...JUST AT A LESS
INTENSE PACE.
THEN BY THIS EVENING THE SNOW COVERAGE AND INTENSITY WILL INCREASE
AGAIN AS ANOTHER NORTHERN STREAM SYSTEM MOVES IN. AHEAD OF THIS
SYSTEM THE FLOW WILL SWING AROUND TO THE WSW AND THE BEST LAKE
ENHANCED SNOWS SHOULD OCCUR WEST OF U.S. 131 AND NORTH OF HOLLAND.
THIS FLOW COULD ALSO PRODUCE A CONVERGENCE ZONE SOMEWHERE NEAR I-96
WITH THE COLD AIR WRAPPING AROUND THE SOUTHERN END OF THE LAKE. THE
SNOW WILL ALSO SPREAD FURTHER INLAND WITH THE SYNOPTIC ELEMENT
TONIGHT.
BY SATURDAY MORNING...BEHIND THIS SYSTEM...THE WINDS TURN BACK TO
THE NW AND SHOULD SHIFT THE LAKE ENHANCED FOCUS TO THE THE SW CORNER
OF THE CWA. THE I-96 CONVERGENCE BAND COULD LAST INTO SATURDAY
MORNING...THEN DIMINISH. ALL SNOW SHOWERS ARE EXPECTED TO FINALLY
DIMINISH INTO SATURDAY AFTERNOON AS INVERSION HEIGHTS LOWER.
THEREFORE FOR HEADLINES...HAVE DECIDED TO EXTEND THE LAKE EFFECT
SNOW WARNING FOR MUCH OF THE SW HALF OF THE CWA...ROUGHLY FROM
MBL-Y70-BTL FOR TODAY THROUGH TONIGHT. AGAIN...EXPECT A LULL IN THE
SNOWFALL INTENSITY THIS AFTERNOON...WITH A RAPID RAMP UP RETURNING
THIS EVENING. WILL CANCEL THE ADVISORY FURTHER INLAND FOR TODAY AS
ANY ACCUMS SHOULD BE MINIMAL. THEN WILL HAVE A NEW ADVISORY FOR
TONIGHT FOR ALL BUT THE NE COUNTIES AS THE SNOW REDEVELOPS. MOST OF
THE HEADLINES WILL END BY SATURDAY MORNING...HOWEVER WILL KEEP THE
SW CORNER OF THE CWA COVERED WITH WARNING THROUGH 18Z SAT WITH THE
NW FLOW ENHANCEMENT CAUSING LINGERING SNOWS.
WESTERLY WINDS WILL CONTINUE TO CAUSE DRIFTING SNOW TODAY AND
TONIGHT TO ADD TO THE IMPACTS. THE WINDS SHOULD FINALLY SUBSIDE
LATE TONIGHT AND REMAIN FAIRLY LIGHT INTO SATURDAY.
ANOTHER SPIKE IN THE SNOW ACTIVITY IS EXPECTED LATE SATURDAY
NIGHT/SUNDAY MORNING WITH ANOTHER SHORT WAVE. HOWEVER AT THIS POINT
IT LOOKS TO BE A QUICKER HITTING SYSTEM.
.LONG TERM...(SUNDAY NIGHT THROUGH THURSDAY)
ISSUED AT 339 AM EST FRI FEB 1 2013
THE OVERALL PATTERN FEATURES CLIPPER SYSTEMS ROTATING AROUND
THE SOUTHERN EDGE OF THE POLAR VORTEX THROUGH TUESDAY. THAT WILL
KEEP SOUTHWEST MICHIGAN WITH BELOW NORMAL TEMPERATURES AND SNOW EACH
DAY. NO MAJOR STORMS ARE EXPECTED BUT LOCALLY SIGNIFICANT LAKE
EFFECT SNOW IS POSSIBLE INTO TUESDAY.
AS THAT POWERHOUSE EAST ASIAN JET BREAKS THROUGH THE WESTERN UPPER
RIDGE IN THE TUESDAY TIME FRAME... THE POLAR VORTEX WILL BE SHIFTED
NORTHWARD FARTHER NORTH INTO CANADA. THAT WILL ALLOW FOR A BREAK IN
THE SNOWY AND COLD WEATHER PATTERN WE HAVE HAD IN SOUTHWEST MICHIGAN
DURING THE MID TO LATE WEEK TIME FRAME. IT SHOULD BE NOTED THAT FOR
THE PAST 4 NIGHTS... EACH RUN OF THE GFS AND ECMWF HAS BEEN COOLER
AT THE LONGER RANGES. CURRENTLY SURFACE TEMPERATURES MAY NOT GET
ABOVE FREEZING OVER MOST OF THE CWA UNTIL THE WEEKEND OF THE 8TH OF
FEBRUARY.
THE MONDAY SYSTEM... WHICH 4 DAYS AGO WAS FORECAST OVER LAKE
SUPERIOR... IS NOW FORECAST TO TRACK SOUTH OF LAKE MICHIGAN DURING
MONDAY AFTERNOON. THIS SHOULD BRING A TRACK OF LIGHT SNOW OVER THE
SOUTHERN AND CENTRAL CWA.
NEXT IN LINE IS A SYSTEM THAT TRACKS FROM CENTRAL BRITISH COLUMBIA
MONDAY TO SOUTHERN LAKE MICHIGAN BY TUESDAY AFTERNOON. WITH COLDER
AIR IN PLACE (LATEST MODEL ROUND ARE COLDER) COULD BE ANOTHER
SOUTHWEST FLOW SNOW EVENT. MOST OF THE CWA WOULD GET 1 TO 3 INCHES
OTHERWISE FROM THIS ONE.
HIGH PRESSURE AIDED BY THE POLAR JET BEING OVER MICHIGAN SHOULD
LARGELY KILL THE LAKE EFFECT SNOW MACHINE. THAT WILL BE FOLLOWED BY
A MORE SOUTHERN STREAM SYSTEM THURSDAY OR LATER WITH A WARMING TREND
BEING NOTED.
BOTTOM LINE... SNOW AND COLD INTO TUESDAY THEN A WARMING TREND.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SATURDAY AFTERNOON)
ISSUED AT 1247 PM EST FRI FEB 1 2013
MAIN FOCUS WITH THE 18Z SET OF FCSTS WILL BE LAKE EFFECT TRENDS
TODAY AND THEN TRENDS LATE THIS EVENING INTO SAT MORNING WITH THE
WAVE OF LOW PRESSURE THAT WILL BE MOVING THROUGH.
LAKE EFFECT SNOW SHOWERS HAVE GENERALLY LOST A BIT OF INTENSITY
THIS MORNING AS SOME RIDGING MOVES IN TEMPORARILY. SOME LOCALIZED
HEAVIER SNOW SHOWERS ARE BRINGING VSBYS DOWN INTO THE LIFR
CATEGORY. WE SHOULD SEE THESE CONDITIONS BECOME LESS AND LESS
PREVALENT THROUGH THE AFTERNOON.
AS MENTIONED ABOVE...THE BREAK WILL BE SHORT LIVED. A WAVE OF LOW
PRESSURE WILL SLIDE IN ACROSS THE AREA TOWARD MIDNIGHT EST OR 05Z.
LIGHT SNOW WILL BREAK OUT AT ALL TERMINALS BY 07-08Z. IFR IS
LIKELY AT ALL THE SITES. KMKG AND KGRR HAVE A GOOD CHANCE OF
SEEING LIFR/VLIFR CONDITIONS AS WE ARE EXPECTING A HEAVIER LAKE
ENHANCED BAND FROM THE SW TO AFFECT THOSE AREAS. THE WAVE SHOULD
MOVE OUT LATE IN THE PERIOD...AND LEAVE SOME LIGHT LAKE EFFECT AND
IMPROVING CONDITIONS.
&&
.MARINE...
ISSUED AT 339 AM EST FRI FEB 1 2013
WILL REPLACE THE GALE WARNING WITH A SMALL CRAFT ADVISORY AS
WESTERLY WINDS SLOWLY DIMINISH.
&&
.HYDROLOGY...
ISSUED AT 339 AM EST FRI FEB 1 2013
LITTLE CHANGE TO THE OVERALL HYDRO SITUATION. THE ICE JAM NEAR
ROGERS HEIGHTS CONTINUES TO WARRANT A FLOOD WARNING. THE WHITE
RIVER IN WHITEHALL REMAINS OUT OF IT/S BANKS...ALTHOUGH THE CREST
HAS ALREADY OCCURRED AND CONDITIONS SHOULD IMPROVE BY THIS EVENING.
SEVERAL OTHER RIVERS ARE IMPACTING LOW LAYING AREAS WHERE ADVISORIES
HAVE BEEN ISSUED. OVERALL CRESTS HAVE OCCURRED OR WILL OCCUR WITHIN
THE 24 HOURS.
&&
.GRR WATCHES/WARNINGS/ADVISORIES...
MI...LAKE EFFECT SNOW WARNING UNTIL 1 PM EST SATURDAY FOR MIZ056-057-
064-065-071-072.
LAKE EFFECT SNOW WARNING UNTIL 7 AM EST SATURDAY FOR MIZ037-043-
044-050-058-066-073.
LAKE EFFECT SNOW ADVISORY FROM 7 PM THIS EVENING TO 7 AM EST
SATURDAY FOR MIZ038-045-051-059-067-074.
LM...SMALL CRAFT ADVISORY UNTIL NOON EST SATURDAY FOR LMZ844>849.
&&
$$
UPDATE...WDM
SYNOPSIS...JK
SHORT TERM...JK
LONG TERM...WDM
AVIATION...NJJ
HYDROLOGY...JK
MARINE...JK
AREA FORECAST DISCUSSION
NWS DETROIT/PONTIAC MI
1231 PM EST FRI FEB 1 2013
.AVIATION...
//DISCUSSION...
SOME LIGHT LAKE EFFECT SNOW SHOWERS WILL BE POSSIBLE THROUGH THE
EARLY PART OF THIS AFTERNOON. HOWEVER...WITH LOWER WIND SPEEDS AND
WINDS EVENTUALLY SHIFTING TO THE SOUTHWEST DUE TO A SURFACE RIDGE
BUILDING INTO THE AREA...SNOW SHOWERS WILL BE LESS INTENSE THAN
YESTERDAY. SNOW SHOWERS WILL SLOWLY DIMINISH BY LATE AFTERNOON. THE
NEXT CHANCE FOR IMPACTFUL SNOW WILL ARRIVE SATURDAY MORNING AS A
SHORTWAVE TRACKS JUST TO THE SOUTH OF MICHIGAN CLIPPING SOUTHERN
MICHIGAN. WHILE ALL TAF SITES HAVE SNOW IN THE FORECAST...THE
SOUTHERN TAF SITES /DTW...DET...YIP/ HAVE THE GREATEST CHANCE TO SEE
ACCUMULATING SNOW SATURDAY MORNING.
FOR DTW...BANDS OF SCATTERED SNOW SHOWERS WILL CONTINUE TO IMPACT
THE TERMINAL OVER THE NEXT FEW HOURS. SNOW SHOWERS WILL SLOWLY COME
TO AN END AS WINDS SHIFT SOUTHWEST AND LINGERING SNOW SHOWERS MOVE
NORTH AND DISSIPATE.
//DTW THRESHOLD THREATS...
* HIGH CONFIDENCE THAT CEILINGS WILL REMAIN BELOW 5000 FT FOR MOST
OF THE TAF PERIOD.
&&
.PREV DISCUSSION...ISSUED 352 AM EST FRI FEB 1 2013
SHORT TERM...TODAY AND TONIGHT
A DOMINANT LONGWAVE TROUGH IS IN PLACE ACROSS MUCH OF EASTERN NORTH
AMERICA. THE AXIS OF THE TROUGH IS PULLING AWAY FROM THE CENTRAL
GREAT LAKES THIS MORNING IN RESPONSE TO THE TROUGH PIVOTING INTO A
NEUTRAL TILT. AS THE AXIS SLIDES EASTWARD...THE NORTHERN ENTRANCE
BRANCH OF THE MAIN POLAR WESTERLY MAXIMUM WILL MOVE IN OVERHEAD.
LOCALIZED CONFLUENCE ALOFT WITH THIS ENTRANCE JETLET WILL SUPPORT
DIFFERENTIAL HEIGHT RISES AND VERY EFFICIENT VEERING OF THE TOTAL
COLUMN WIND. THIS WILL CAUSE WINDS TO EVOLVE FROM NORTHWESTERLY THIS
MORNING TO A SOLID SOUTHWESTERLY TRAJECTORY BY THIS AFTERNOON.
THE FAVORABLE DOWNWIND THERMODYNAMIC ENVIRONMENT THAT HAS SHOWN TO
BE SUPPORTIVE OF LES APPEARS TO HAVE BEEN PARTLY DEPENDENT UPON
HIGHER MOISTURE CONTENT RESIDING AT AND JUST ABOVE THE INVERSION
BASE (~750MB OR ~7500 FT AGL). RUC AND NAM SOLUTIONS DEPICTED THAT
DRY AIR ADVECTION (ABSOLUTE/MIXING RATIO) WOULD OCCUR IN THE 3-6Z
TIMEFRAME. THIS HAS OCCURRED WITH .5 REFLECTIVITY QUIETING AND
SURFACE OBSERVATIONS VOID OF ANY IMPACTFUL SNOW. RIDGING AND WARMING
ALOFT WILL CAUSE INVERSION HEIGHTS TO CRASH TO ROUGHLY 3500
FT...WITH SATURATION OCCURRING THROUGH THE TOP OF THE SQUATTY
BOUNDARY LAYER. PLAYED THIS IN THE FORECAST BY REMOVING POPS FOR
MOST AREAS...INSTEAD OPTING FOR A MENTION OF FLURRIES.
ENHANCED MIDLEVEL MOISTURE WILL WASH ACROSS LOWER MICHIGAN TONIGHT
FROM THE WEST. LOW LEVEL THERMAL/WIND PROGS SUGGEST THAT AN ENHANCED
CONVERGENCE ZONE MAY SET UP SHOP OFF OF THE SOUTHERN RIM OF LAKE
MICHIGAN. WIND TRAJECTORIES SUGGEST THIS BAND LIFTING INTO THE
SAGINAW VALLEY APPX/AFTER 9Z. LOWS TONIGHT ARE EXPECTED TO DROP INTO
THE SINGLE DIGITS ABOVE ZERO NORTH...10-13 DEGREE RANGE SOUTH OF I
69. THERE IS EXPECTED TO BE ENOUGH SKY FRACTION/SFC WINDS TO LIMIT A
STRONGER COOLING RESPONSE.
LONG TERM...SATURDAY THROUGH NEXT THURSDAY
NORTHWEST FLOW ALOFT WILL DOMINATE THE FORECAST CYCLE AS UPPER LEVEL
TROUGH REMAINS OVER THE EASTERN CONUS. THE WEST COAST RIDGE LOOKS TO
TRY TO RELEASE FROM THE WEST COAST EARLY/MID NEXT WEEK BUT SEVERAL
SHORTWAVES ROUNDING THE RIDGE WILL DIVE DOWN INTO THE NORTHERN
PLAINS AND REINFORCE THE TROUGH. THIS WILL KEEP THE RIDGE IN PLACE
TIL THE END OF THE WEEK. COOLER THAN AVERAGE AIRMASS WILL STAY
ROOTED OVER THE GREAT LAKES THIS WEEK AS THE MAIN BAROCLINIC ZONE
STAYS LOCATED AT OR SOUTH OF THE OHIO VALLEY WITH THE COLDEST ARCTIC
AIR RESIDING JUST TO OUR NORTH IN EASTERN CANADA. AS IS TYPICAL IN
NW FLOW SETUPS...SEVERAL SHORTWAVES WILL PASS THROUGH THE REGION
THIS WEEK GIVING US A FEW CHANCES OF SNOWFALL. NOT EXPECTING ANY
SIGNIFICANT ACCUMULATIONS AS THE OVERALL JET STRUCTURE LOOKS RATHER
CHAOTIC AT TIMES BREAKING UP INTO PARALLELING SEGMENTS WITH WEAKER
FLOW THEN WE HAVE SEEN THE LAST FEW WEEKS. IN ADDITION TO MOISTURE
AMOUNTS REMAINING ON THE LOW SIDE WITH PWATS STRUGGLING TO REACH A
THIRD OF AN INCH.
A COMPLEX PATTERN SETS UP FOR SATURDAY AS THE NORTHERN STREAM LOOKS
TO RELOCATE WESTWARD. A SHEARED OUT VORT MAX WILL PASS THROUGH THE
NORTHERN GREAT LAKES WITH THE WEAKENING JETLET WHILE A PAIR OF
SHORTWAVES WILL TRACK TROUGH THE OHIO VALLEY THROUGH THE
STRENGTHENING WESTERN STREAM. THE EARLIER SYSTEM WILL PULL SOMEWHAT
HIGHER THETA E AIRMASS NORTHWARD FOR THE SECOND SYSTEM TO WORK WITH
IN THE EVENING. MODEL SOUNDINGS DO NOT RESPOND WITH MUCH ADDITIONAL
PWAT OR QPF THOUGH. INTRODUCED LIKELY POPS ALONG THE EXTREME SOUTH
WHILE KEEPING CHANCE POPS FOR THE REST OF THE AREA. LAKE ENHANCEMENT
MAY LEAD TO SOME ADDITIONAL SNOWFALL OVER THE TYPICAL AREAS TO THE
WEST BUT WILL KEEP HIGH CHANCE POPS FOR NOW TO ACCOUNT FOR THIS.
LOOKS LIKE SNOW SHOWERS THROUGH MOST OF THE DAY WITH A POSSIBLE LULL
IN THE EVENING BEFORE THE SECOND SYSTEM WORKS INTO THE AREA SATURDAY
NIGHT. LAKE EFFECT SHOWERS WILL LIKELY LINGER INTO SUNDAY AFTERNOON
UNTIL NORTHERN EXTENT OF SFC HIGH PRESSURE SLIDES INTO THE AREA.
THE SECOND WAVE WILL BRING A TOUCH OF ARCTIC AIR BACK OVER THE AREA
ON SUNDAY WITH SFC HIGH PRESSURE ALLOWING TEMPS TO DROP OVERNIGHT.
MODELS CONTINUE TO THEN BRING A FAST MOVING CLIPPER THROUGH EARLY
MONDAY FOR THE NEXT CHANCE OF SNOW SHOWERS...BUT THE UPPER LEVEL
FLOW REMAINS VERY CHAOTIC LEADING TO LOW CONFIDENCE WITH THIS SYSTEM.
MARINE...
WITH THE UPPER LEVEL TROUGH PULLING EAST OF THE REGION...SURFACE
WINDS WILL STEADILY WEAKEN TODAY. CURRENT SURFACE OBSERVATIONS
ACROSS THE LAKE HURON BASIN SHOW NO REAL CONDITIONS OF CONCERN. WILL
GO AHEAD AND ALLOW THE FREEZING SPRAY WARNING TO EXPIRE. SURFACE
HIGH PRESSURE BUILDING INTO THE OHIO RIVER VALLEY THIS AFTERNOON
WILL CAUSE WINDS TO VEER SOUTHWESTERLY BY THIS EVENING. WARM
ADVECTION PATTERN WILL KEEP WINDS IN THE 10 TO 20 KNOT RANGE. THE
NEXT CHANCE FOR NOTABLE MARINE WEATHER WILL BE SUNDAY EVENING AS
ANOTHER COLD AIRMASS WILL SWEEP ACROSS THE RELATIVELY WARMER WATERS.
RIGHT NOW...IT APPEARS THAT HIGH END WIND GUSTS SUNDAY NIGHT WILL
REMAIN 30 KNOTS OR LESS.
&&
.DTX WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LAKE HURON...NONE.
LAKE ST CLAIR...NONE.
MI WATERS OF LAKE ERIE...NONE.
&&
$$
AVIATION.....RK
SHORT TERM...CB
LONG TERM....DRK
MARINE.......CB
YOU CAN OBTAIN YOUR LATEST NATIONAL WEATHER SERVICE FORECASTS ONLINE
AT WWW.WEATHER.GOV/DETROIT (ALL LOWER CASE).
AREA FORECAST DISCUSSION
NWS GRAND RAPIDS MI
720 AM EST FRI FEB 1 2013
.SYNOPSIS...
ISSUED AT 339 AM EST FRI FEB 1 2013
AFTER MORNING SNOWS TODAY...THE SNOW SHOWERS ARE EXPECTED TO DIMINISH
SOMEWHAT THIS AFTERNOON. HOWEVER THE SNOW IS EXPECTED TO INCREASE
IN COVERAGE AND INTENSITY ONCE AGAIN BY THIS EVENING. SEVERAL
INCHES OF SNOW WILL BE POSSIBLE AGAIN TONIGHT...ESPECIALLY WEST OF
U.S. 131 AND NORTH OF HOLLAND. THE SNOW INTENSITY WILL BE HEAVY
ENOUGH TO OCCASIONALLY PRODUCE NEAR WHITEOUT CONDITIONS.
MEANWHILE INLAND AREAS SHOULD ALSO SEE SNOWFALL TONIGHT...WITH
SOMEWHAT LESS ACCUMULATION.
THE SNOW INTENSITY AND COVERAGE IS EXPECTED TO DIMINISH BY
SATURDAY AFTERNOON. THEN ANOTHER WEAKER SYSTEM MOVES IN FOR SUNDAY
MORNING...LIKELY PRODUCING MORE ACCUMULATING SNOW.
&&
.UPDATE...
ISSUED AT 658 AM EST FRI FEB 1 2013
BASED ON THE LATEST RADAR LOOPS IN CONJUNCTION WITH THE LATEST HRRR
AND RAP DATA.... I INCREASED THE POP CONDITIONAL NEAR AND WEST OF
US-131 THROUGH LATE MORNING. BOUNDARY LAYER WINDS BECOME MORE
WESTERLY DURING THE DAY TODAY SO THE SNOW BANDS WILL BECOME MORE
EAST / WEST. I DO EXPECT AN INCH OR TWO BETWEEN NOW AND NOON SOUTH
OF MUSKEGON AND WEST OF GRAND RAPIDS.
DAY TIME HEATING WILL HELP TO SPREAD THE SNOW SHOWERS INLAND BUT
THE INTENSITY SHOULD BE NOT MUCH MORE THAN FLURRIES EAST OF
US-131. I INCREASED POP THERE TOO SINCE MORE THAN LIKELY THERE
WILL BE SOME SNOW SHOWERS EVEN IF THEY ARE LIGHT.
&&
.SHORT TERM...(TODAY THROUGH SUNDAY)
ISSUED AT 339 AM EST FRI FEB 1 2013
WILL ADJUST HEADLINES FOR THIS LONG DURATION EVENT.
WE WILL CONTINUE TO SEE FAIRLY INTENSE SNOW SHOWERS THIS MORNING
AS INVERSION HEIGHTS REMAIN HIGH AND THERE REMAINS LIFT WITHIN THE
DGZ. HOWEVER TOWARD MID DAY THE INVERSION HEIGHTS LOWER AND THERE
WILL BE LESS LIFT AS A SHORT WAVE EXITS THE REGION. THIS LULL WILL
PROBABLY ONLY LAST 6 TO 8 HOURS...SO NOT REALLY LONG ENOUGH TO
CALL THE EVENT OVER...AS THE SNOW WILL CONTINUE...JUST AT A LESS
INTENSE PACE.
THEN BY THIS EVENING THE SNOW COVERAGE AND INTENSITY WILL INCREASE
AGAIN AS ANOTHER NORTHERN STREAM SYSTEM MOVES IN. AHEAD OF THIS
SYSTEM THE FLOW WILL SWING AROUND TO THE WSW AND THE BEST LAKE
ENHANCED SNOWS SHOULD OCCUR WEST OF U.S. 131 AND NORTH OF HOLLAND.
THIS FLOW COULD ALSO PRODUCE A CONVERGENCE ZONE SOMEWHERE NEAR I-96
WITH THE COLD AIR WRAPPING AROUND THE SOUTHERN END OF THE LAKE. THE
SNOW WILL ALSO SPREAD FURTHER INLAND WITH THE SYNOPTIC ELEMENT
TONIGHT.
BY SATURDAY MORNING...BEHIND THIS SYSTEM...THE WINDS TURN BACK TO
THE NW AND SHOULD SHIFT THE LAKE ENHANCED FOCUS TO THE THE SW CORNER
OF THE CWA. THE I-96 CONVERGENCE BAND COULD LAST INTO SATURDAY
MORNING...THEN DIMINISH. ALL SNOW SHOWERS ARE EXPECTED TO FINALLY
DIMINISH INTO SATURDAY AFTERNOON AS INVERSION HEIGHTS LOWER.
THEREFORE FOR HEADLINES...HAVE DECIDED TO EXTEND THE LAKE EFFECT
SNOW WARNING FOR MUCH OF THE SW HALF OF THE CWA...ROUGHLY FROM
MBL-Y70-BTL FOR TODAY THROUGH TONIGHT. AGAIN...EXPECT A LULL IN THE
SNOWFALL INTENSITY THIS AFTERNOON...WITH A RAPID RAMP UP RETURNING
THIS EVENING. WILL CANCEL THE ADVISORY FURTHER INLAND FOR TODAY AS
ANY ACCUMS SHOULD BE MINIMAL. THEN WILL HAVE A NEW ADVISORY FOR
TONIGHT FOR ALL BUT THE NE COUNTIES AS THE SNOW REDEVELOPS. MOST OF
THE HEADLINES WILL END BY SATURDAY MORNING...HOWEVER WILL KEEP THE
SW CORNER OF THE CWA COVERED WITH WARNING THROUGH 18Z SAT WITH THE
NW FLOW ENHANCEMENT CAUSING LINGERING SNOWS.
WESTERLY WINDS WILL CONTINUE TO CAUSE DRIFTING SNOW TODAY AND
TONIGHT TO ADD TO THE IMPACTS. THE WINDS SHOULD FINALLY SUBSIDE
LATE TONIGHT AND REMAIN FAIRLY LIGHT INTO SATURDAY.
ANOTHER SPIKE IN THE SNOW ACTIVITY IS EXPECTED LATE SATURDAY
NIGHT/SUNDAY MORNING WITH ANOTHER SHORT WAVE. HOWEVER AT THIS POINT
IT LOOKS TO BE A QUICKER HITTING SYSTEM.
.LONG TERM...(SUNDAY NIGHT THROUGH THURSDAY)
ISSUED AT 339 AM EST FRI FEB 1 2013
THE OVERALL PATTERN FEATURES CLIPPER SYSTEMS ROTATING AROUND
THE SOUTHERN EDGE OF THE POLAR VORTEX THROUGH TUESDAY. THAT WILL
KEEP SOUTHWEST MICHIGAN WITH BELOW NORMAL TEMPERATURES AND SNOW EACH
DAY. NO MAJOR STORMS ARE EXPECTED BUT LOCALLY SIGNIFICANT LAKE
EFFECT SNOW IS POSSIBLE INTO TUESDAY.
AS THAT POWERHOUSE EAST ASIAN JET BREAKS THROUGH THE WESTERN UPPER
RIDGE IN THE TUESDAY TIME FRAME... THE POLAR VORTEX WILL BE SHIFTED
NORTHWARD FARTHER NORTH INTO CANADA. THAT WILL ALLOW FOR A BREAK IN
THE SNOWY AND COLD WEATHER PATTERN WE HAVE HAD IN SOUTHWEST MICHIGAN
DURING THE MID TO LATE WEEK TIME FRAME. IT SHOULD BE NOTED THAT FOR
THE PAST 4 NIGHTS... EACH RUN OF THE GFS AND ECMWF HAS BEEN COOLER
AT THE LONGER RANGES. CURRENTLY SURFACE TEMPERATURES MAY NOT GET
ABOVE FREEZING OVER MOST OF THE CWA UNTIL THE WEEKEND OF THE 8TH OF
FEBRUARY.
THE MONDAY SYSTEM... WHICH 4 DAYS AGO WAS FORECAST OVER LAKE
SUPERIOR... IS NOW FORECAST TO TRACK SOUTH OF LAKE MICHIGAN DURING
MONDAY AFTERNOON. THIS SHOULD BRING A TRACK OF LIGHT SNOW OVER THE
SOUTHERN AND CENTRAL CWA.
NEXT IN LINE IS A SYSTEM THAT TRACKS FROM CENTRAL BRITISH COLUMBIA
MONDAY TO SOUTHERN LAKE MICHIGAN BY TUESDAY AFTERNOON. WITH COLDER
AIR IN PLACE (LATEST MODEL ROUND ARE COLDER) COULD BE ANOTHER
SOUTHWEST FLOW SNOW EVENT. MOST OF THE CWA WOULD GET 1 TO 3 INCHES
OTHERWISE FROM THIS ONE.
HIGH PRESSURE AIDED BY THE POLAR JET BEING OVER MICHIGAN SHOULD
LARGELY KILL THE LAKE EFFECT SNOW MACHINE. THAT WILL BE FOLLOWED BY
A MORE SOUTHERN STREAM SYSTEM THURSDAY OR LATER WITH A WARMING TREND
BEING NOTED.
BOTTOM LINE... SNOW AND COLD INTO TUESDAY THEN A WARMING TREND.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SATURDAY MORNING)
ISSUED AT 720 AM EST FRI FEB 1 2013
SNOW SHOWERS WILL DECREASE IN INTENSITY BUT NOT END THIS AFTERNOON
AS MID LEVEL RIDGING LOWERS INVERSION HEIGHTS. WINDS IN THE
BOUNDARY LAYER WILL BECOME MORE WESTRLY BY THIS AFTERNOON SO SNOW
BANDS WILL BE MORE WEST TO EAST. ALL BUT THE LAN TAF SITE HAVE IFR
CONDITIONS THIS MORNING. THAT MAY IMPROVE TO MVFR THIS AFTERNOON
BEFORE THE NEXT SYSTEM BRINGS SOLID IFR/LIFR CONDITIONS IN SNOW
BACK TO THE AREA BY MIDNIGHT.
&&
.MARINE...
ISSUED AT 339 AM EST FRI FEB 1 2013
WILL REPLACE THE GALE WARNING WITH A SMALL CRAFT ADVISORY AS
WESTERLY WINDS SLOWLY DIMINISH.
&&
.HYDROLOGY...
ISSUED AT 339 AM EST FRI FEB 1 2013
LITTLE CHANGE TO THE OVERALL HYDRO SITUATION. THE ICE JAM NEAR
ROGERS HEIGHTS CONTINUES TO WARRANT A FLOOD WARNING. THE WHITE
RIVER IN WHITEHALL REMAINS OUT OF IT/S BANKS...ALTHOUGH THE CREST
HAS ALREADY OCCURRED AND CONDITIONS SHOULD IMPROVE BY THIS EVENING.
SEVERAL OTHER RIVERS ARE IMPACTING LOW LAYING AREAS WHERE ADVISORIES
HAVE BEEN ISSUED. OVERALL CRESTS HAVE OCCURRED OR WILL OCCUR WITHIN
THE 24 HOURS.
&&
.GRR WATCHES/WARNINGS/ADVISORIES...
MI...LAKE EFFECT SNOW WARNING UNTIL 1 PM EST SATURDAY FOR MIZ056-057-
064-065-071-072.
LAKE EFFECT SNOW WARNING UNTIL 7 AM EST SATURDAY FOR MIZ037-043-
044-050-058-066-073.
LAKE EFFECT SNOW ADVISORY FROM 7 PM THIS EVENING TO 7 AM EST
SATURDAY FOR MIZ038-045-051-059-067-074.
LM...SMALL CRAFT ADVISORY UNTIL NOON EST SATURDAY FOR LMZ844>849.
&&
$$
UPDATE...WDM
SYNOPSIS...JK
SHORT TERM...JK
LONG TERM...WDM
AVIATION...WDM
HYDROLOGY...JK
MARINE...JK
AREA FORECAST DISCUSSION
NWS DETROIT/PONTIAC MI
612 AM EST FRI FEB 1 2013
.AVIATION...
//DISCUSSION...
THE DRY MIDLEVEL AIR MAKING INROADS ACROSS SOUTHEASTERN MICHIGAN
THIS MORNING HAS BEEN SUCCESSFUL IN WEAKENING THE SNOW SHOWER
ACTIVITY. MODEL SOUNDINGS SHOW THAT LAPSE RATES WILL BE STEEP ENOUGH
IN THE LOWEST FEW THOUSAND FEET TO SUPPORT FLURRIES AND LIGHT SNOW
SHOWERS TODAY. HOWEVER...DEPTH OF LOWER STABILITY WILL BE
DRAMATICALLY LESS THAN YESTERDAY SO BEHAVIOR/VIGOR OF TODAYS
ACTIVITY WILL BE MARKEDLY LESS. A BUILDING SURFACE RIDGE WILL CAUSE
WIND DIRECTIONS TO VEER WESTERLY TO SOUTHWESTERLY DURING THE DAY.
FOR DTW...THE CONCENTRATED BAND OF SNOW SHOWERS HAS WEAKENED
DRAMATICALLY OVERNIGHT. THE CURRENT AXIS IS IMMEDIATELY SOUTH AND
WEST OF THE TERMINAL THIS MORNING. THE POTENTIAL EXISTS FOR
INDIVIDUAL CONVECTIVE ELEMENTS TO BRUSH THE TERMINAL FOR A FEW HOURS
THIS MORNING BEFORE MIGRATING NORTHWARD.
//DTW THRESHOLD THREATS...
* MEDIUM CONFIDENCE IN CEILING BELOW 5000 FT THROUGH THE TAF
PERIOD.
&&
.PREV DISCUSSION...ISSUED 352 AM EST FRI FEB 1 2013
SHORT TERM...TODAY AND TONIGHT
A DOMINANT LONGWAVE TROUGH IS IN PLACE ACROSS MUCH OF EASTERN NORTH
AMERICA. THE AXIS OF THE TROUGH IS PULLING AWAY FROM THE CENTRAL
GREAT LAKES THIS MORNING IN RESPONSE TO THE TROUGH PIVOTING INTO A
NEUTRAL TILT. AS THE AXIS SLIDES EASTWARD...THE NORTHERN ENTRANCE
BRANCH OF THE MAIN POLAR WESTERLY MAXIMUM WILL MOVE IN OVERHEAD.
LOCALIZED CONFLUENCE ALOFT WITH THIS ENTRANCE JETLET WILL SUPPORT
DIFFERENTIAL HEIGHT RISES AND VERY EFFICIENT VEERING OF THE TOTAL
COLUMN WIND. THIS WILL CAUSE WINDS TO EVOLVE FROM NORTHWESTERLY THIS
MORNING TO A SOLID SOUTHWESTERLY TRAJECTORY BY THIS AFTERNOON.
THE FAVORABLE DOWNWIND THERMODYNAMIC ENVIRONMENT THAT HAS SHOWN TO
BE SUPPORTIVE OF LES APPEARS TO HAVE BEEN PARTLY DEPENDENT UPON
HIGHER MOISTURE CONTENT RESIDING AT AND JUST ABOVE THE INVERSION
BASE (~750MB OR ~7500 FT AGL). RUC AND NAM SOLUTIONS DEPICTED THAT
DRY AIR ADVECTION (ABSOLUTE/MIXING RATIO) WOULD OCCUR IN THE 3-6Z
TIMEFRAME. THIS HAS OCCURRED WITH .5 REFLECTIVITY QUIETING AND
SURFACE OBSERVATIONS VOID OF ANY IMPACTFUL SNOW. RIDGING AND WARMING
ALOFT WILL CAUSE INVERSION HEIGHTS TO CRASH TO ROUGHLY 3500
FT...WITH SATURATION OCCURRING THROUGH THE TOP OF THE SQUATTY
BOUNDARY LAYER. PLAYED THIS IN THE FORECAST BY REMOVING POPS FOR
MOST AREAS...INSTEAD OPTING FOR A MENTION OF FLURRIES.
ENHANCED MIDLEVEL MOISTURE WILL WASH ACROSS LOWER MICHIGAN TONIGHT
FROM THE WEST. LOW LEVEL THERMAL/WIND PROGS SUGGEST THAT AN ENHANCED
CONVERGENCE ZONE MAY SET UP SHOP OFF OF THE SOUTHERN RIM OF LAKE
MICHIGAN. WIND TRAJECTORIES SUGGEST THIS BAND LIFTING INTO THE
SAGINAW VALLEY APPX/AFTER 9Z. LOWS TONIGHT ARE EXPECTED TO DROP INTO
THE SINGLE DIGITS ABOVE ZERO NORTH...10-13 DEGREE RANGE SOUTH OF I
69. THERE IS EXPECTED TO BE ENOUGH SKY FRACTION/SFC WINDS TO LIMIT A
STRONGER COOLING RESPONSE.
LONG TERM...SATURDAY THROUGH NEXT THURSDAY
NORTHWEST FLOW ALOFT WILL DOMINATE THE FORECAST CYCLE AS UPPER LEVEL
TROUGH REMAINS OVER THE EASTERN CONUS. THE WEST COAST RIDGE LOOKS TO
TRY TO RELEASE FROM THE WEST COAST EARLY/MID NEXT WEEK BUT SEVERAL
SHORTWAVES ROUNDING THE RIDGE WILL DIVE DOWN INTO THE NORTHERN
PLAINS AND REINFORCE THE TROUGH. THIS WILL KEEP THE RIDGE IN PLACE
TIL THE END OF THE WEEK. COOLER THAN AVERAGE AIRMASS WILL STAY
ROOTED OVER THE GREAT LAKES THIS WEEK AS THE MAIN BAROCLINIC ZONE
STAYS LOCATED AT OR SOUTH OF THE OHIO VALLEY WITH THE COLDEST ARCTIC
AIR RESIDING JUST TO OUR NORTH IN EASTERN CANADA. AS IS TYPICAL IN
NW FLOW SETUPS...SEVERAL SHORTWAVES WILL PASS THROUGH THE REGION
THIS WEEK GIVING US A FEW CHANCES OF SNOWFALL. NOT EXPECTING ANY
SIGNIFICANT ACCUMULATIONS AS THE OVERALL JET STRUCTURE LOOKS RATHER
CHAOTIC AT TIMES BREAKING UP INTO PARALLELING SEGMENTS WITH WEAKER
FLOW THEN WE HAVE SEEN THE LAST FEW WEEKS. IN ADDITION TO MOISTURE
AMOUNTS REMAINING ON THE LOW SIDE WITH PWATS STRUGGLING TO REACH A
THIRD OF AN INCH.
A COMPLEX PATTERN SETS UP FOR SATURDAY AS THE NORTHERN STREAM LOOKS
TO RELOCATE WESTWARD. A SHEARED OUT VORT MAX WILL PASS THROUGH THE
NORTHERN GREAT LAKES WITH THE WEAKENING JETLET WHILE A PAIR OF
SHORTWAVES WILL TRACK TROUGH THE OHIO VALLEY THROUGH THE
STRENGTHENING WESTERN STREAM. THE EARLIER SYSTEM WILL PULL SOMEWHAT
HIGHER THETA E AIRMASS NORTHWARD FOR THE SECOND SYSTEM TO WORK WITH
IN THE EVENING. MODEL SOUNDINGS DO NOT RESPOND WITH MUCH ADDITIONAL
PWAT OR QPF THOUGH. INTRODUCED LIKELY POPS ALONG THE EXTREME SOUTH
WHILE KEEPING CHANCE POPS FOR THE REST OF THE AREA. LAKE ENHANCEMENT
MAY LEAD TO SOME ADDITIONAL SNOWFALL OVER THE TYPICAL AREAS TO THE
WEST BUT WILL KEEP HIGH CHANCE POPS FOR NOW TO ACCOUNT FOR THIS.
LOOKS LIKE SNOW SHOWERS THROUGH MOST OF THE DAY WITH A POSSIBLE LULL
IN THE EVENING BEFORE THE SECOND SYSTEM WORKS INTO THE AREA SATURDAY
NIGHT. LAKE EFFECT SHOWERS WILL LIKELY LINGER INTO SUNDAY AFTERNOON
UNTIL NORTHERN EXTENT OF SFC HIGH PRESSURE SLIDES INTO THE AREA.
THE SECOND WAVE WILL BRING A TOUCH OF ARCTIC AIR BACK OVER THE AREA
ON SUNDAY WITH SFC HIGH PRESSURE ALLOWING TEMPS TO DROP OVERNIGHT.
MODELS CONTINUE TO THEN BRING A FAST MOVING CLIPPER THROUGH EARLY
MONDAY FOR THE NEXT CHANCE OF SNOW SHOWERS...BUT THE UPPER LEVEL
FLOW REMAINS VERY CHAOTIC LEADING TO LOW CONFIDENCE WITH THIS SYSTEM.
MARINE...
WITH THE UPPER LEVEL TROUGH PULLING EAST OF THE REGION...SURFACE
WINDS WILL STEADILY WEAKEN TODAY. CURRENT SURFACE OBSERVATIONS
ACROSS THE LAKE HURON BASIN SHOW NO REAL CONDITIONS OF CONCERN. WILL
GO AHEAD AND ALLOW THE FREEZING SPRAY WARNING TO EXPIRE. SURFACE
HIGH PRESSURE BUILDING INTO THE OHIO RIVER VALLEY THIS AFTERNOON
WILL CAUSE WINDS TO VEER SOUTHWESTERLY BY THIS EVENING. WARM
ADVECTION PATTERN WILL KEEP WINDS IN THE 10 TO 20 KNOT RANGE. THE
NEXT CHANCE FOR NOTABLE MARINE WEATHER WILL BE SUNDAY EVENING AS
ANOTHER COLD AIRMASS WILL SWEEP ACROSS THE RELATIVELY WARMER WATERS.
RIGHT NOW...IT APPEARS THAT HIGH END WIND GUSTS SUNDAY NIGHT WILL
REMAIN 30 KNOTS OR LESS.
&&
.DTX WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LAKE HURON...NONE.
LAKE ST CLAIR...NONE.
MI WATERS OF LAKE ERIE...NONE.
&&
$$
AVIATION.....CB
SHORT TERM...CB
LONG TERM....DRK
MARINE.......CB
YOU CAN OBTAIN YOUR LATEST NATIONAL WEATHER SERVICE FORECASTS ONLINE
AT WWW.WEATHER.GOV/DETROIT (ALL LOWER CASE).
AREA FORECAST DISCUSSION
NWS DETROIT/PONTIAC MI
352 AM EST FRI FEB 1 2013
.SHORT TERM...TODAY AND TONIGHT
A DOMINANT LONGWAVE TROUGH IS IN PLACE ACROSS MUCH OF EASTERN NORTH
AMERICA. THE AXIS OF THE TROUGH IS PULLING AWAY FROM THE CENTRAL
GREAT LAKES THIS MORNING IN RESPONSE TO THE TROUGH PIVOTING INTO A
NEUTRAL TILT. AS THE AXIS SLIDES EASTWARD...THE NORTHERN ENTRANCE
BRANCH OF THE MAIN POLAR WESTERLY MAXIMUM WILL MOVE IN OVERHEAD.
LOCALIZED CONFLUENCE ALOFT WITH THIS ENTRANCE JETLET WILL SUPPORT
DIFFERENTIAL HEIGHT RISES AND VERY EFFICIENT VEERING OF THE TOTAL
COLUMN WIND. THIS WILL CAUSE WINDS TO EVOLVE FROM NORTHWESTERLY THIS
MORNING TO A SOLID SOUTHWESTERLY TRAJECTORY BY THIS AFTERNOON.
THE FAVORABLE DOWNWIND THERMODYNAMIC ENVIRONMENT THAT HAS SHOWN TO
BE SUPPORTIVE OF LES APPEARS TO HAVE BEEN PARTLY DEPENDENT UPON
HIGHER MOISTURE CONTENT RESIDING AT AND JUST ABOVE THE INVERSION
BASE (~750MB OR ~7500 FT AGL). RUC AND NAM SOLUTIONS DEPICTED THAT
DRY AIR ADVECTION (ABSOLUTE/MIXING RATIO) WOULD OCCUR IN THE 3-6Z
TIMEFRAME. THIS HAS OCCURRED WITH .5 REFLECTIVITY QUIETING AND
SURFACE OBSERVATIONS VOID OF ANY IMPACTFUL SNOW. RIDGING AND WARMING
ALOFT WILL CAUSE INVERSION HEIGHTS TO CRASH TO ROUGHLY 3500
FT...WITH SATURATION OCCURRING THROUGH THE TOP OF THE SQUATTY
BOUNDARY LAYER. PLAYED THIS IN THE FORECAST BY REMOVING POPS FOR
MOST AREAS...INSTEAD OPTING FOR A MENTION OF FLURRIES.
ENHANCED MIDLEVEL MOISTURE WILL WASH ACROSS LOWER MICHIGAN TONIGHT
FROM THE WEST. LOW LEVEL THERMAL/WIND PROGS SUGGEST THAT AN ENHANCED
CONVERGENCE ZONE MAY SET UP SHOP OFF OF THE SOUTHERN RIM OF LAKE
MICHIGAN. WIND TRAJECTORIES SUGGEST THIS BAND LIFTING INTO THE
SAGINAW VALLEY APPX/AFTER 9Z. LOWS TONIGHT ARE EXPECTED TO DROP INTO
THE SINGLE DIGITS ABOVE ZERO NORTH...10-13 DEGREE RANGE SOUTH OF I
69. THERE IS EXPECTED TO BE ENOUGH SKY FRACTION/SFC WINDS TO LIMIT A
STRONGER COOLING RESPONSE.
&&
.LONG TERM...SATURDAY THROUGH NEXT THURSDAY
NORTHWEST FLOW ALOFT WILL DOMINATE THE FORECAST CYCLE AS UPPER LEVEL
TROUGH REMAINS OVER THE EASTERN CONUS. THE WEST COAST RIDGE LOOKS TO
TRY TO RELEASE FROM THE WEST COAST EARLY/MID NEXT WEEK BUT SEVERAL
SHORTWAVES ROUNDING THE RIDGE WILL DIVE DOWN INTO THE NORTHERN
PLAINS AND REINFORCE THE TROUGH. THIS WILL KEEP THE RIDGE IN PLACE
TIL THE END OF THE WEEK. COOLER THAN AVERAGE AIRMASS WILL STAY
ROOTED OVER THE GREAT LAKES THIS WEEK AS THE MAIN BAROCLINIC ZONE
STAYS LOCATED AT OR SOUTH OF THE OHIO VALLEY WITH THE COLDEST ARCTIC
AIR RESIDING JUST TO OUR NORTH IN EASTERN CANADA. AS IS TYPICAL IN
NW FLOW SETUPS...SEVERAL SHORTWAVES WILL PASS THROUGH THE REGION
THIS WEEK GIVING US A FEW CHANCES OF SNOWFALL. NOT EXPECTING ANY
SIGNIFICANT ACCUMULATIONS AS THE OVERALL JET STRUCTURE LOOKS RATHER
CHAOTIC AT TIMES BREAKING UP INTO PARALLELING SEGMENTS WITH WEAKER
FLOW THEN WE HAVE SEEN THE LAST FEW WEEKS. IN ADDITION TO MOISTURE
AMOUNTS REMAINING ON THE LOW SIDE WITH PWATS STRUGGLING TO REACH A
THIRD OF AN INCH.
A COMPLEX PATTERN SETS UP FOR SATURDAY AS THE NORTHERN STREAM LOOKS
TO RELOCATE WESTWARD. A SHEARED OUT VORT MAX WILL PASS THROUGH THE
NORTHERN GREAT LAKES WITH THE WEAKENING JETLET WHILE A PAIR OF
SHORTWAVES WILL TRACK TROUGH THE OHIO VALLEY THROUGH THE
STRENGTHENING WESTERN STREAM. THE EARLIER SYSTEM WILL PULL SOMEWHAT
HIGHER THETA E AIRMASS NORTHWARD FOR THE SECOND SYSTEM TO WORK WITH
IN THE EVENING. MODEL SOUNDINGS DO NOT RESPOND WITH MUCH ADDITIONAL
PWAT OR QPF THOUGH. INTRODUCED LIKELY POPS ALONG THE EXTREME SOUTH
WHILE KEEPING CHANCE POPS FOR THE REST OF THE AREA. LAKE ENHANCEMENT
MAY LEAD TO SOME ADDITIONAL SNOWFALL OVER THE TYPICAL AREAS TO THE
WEST BUT WILL KEEP HIGH CHANCE POPS FOR NOW TO ACCOUNT FOR THIS.
LOOKS LIKE SNOW SHOWERS THROUGH MOST OF THE DAY WITH A POSSIBLE LULL
IN THE EVENING BEFORE THE SECOND SYSTEM WORKS INTO THE AREA SATURDAY
NIGHT. LAKE EFFECT SHOWERS WILL LIKELY LINGER INTO SUNDAY AFTERNOON
UNTIL NORTHERN EXTENT OF SFC HIGH PRESSURE SLIDES INTO THE AREA.
THE SECOND WAVE WILL BRING A TOUCH OF ARCTIC AIR BACK OVER THE AREA
ON SUNDAY WITH SFC HIGH PRESSURE ALLOWING TEMPS TO DROP OVERNIGHT.
MODELS CONTINUE TO THEN BRING A FAST MOVING CLIPPER THROUGH EARLY
MONDAY FOR THE NEXT CHANCE OF SNOW SHOWERS...BUT THE UPPER LEVEL
FLOW REMAINS VERY CHAOTIC LEADING TO LOW CONFIDENCE WITH THIS SYSTEM.
&&
.MARINE...
WITH THE UPPER LEVEL TROUGH PULLING EAST OF THE REGION...SURFACE
WINDS WILL STEADILY WEAKEN TODAY. CURRENT SURFACE OBSERVATIONS
ACROSS THE LAKE HURON BASIN SHOW NO REAL CONDITIONS OF CONCERN. WILL
GO AHEAD AND ALLOW THE FREEZING SPRAY WARNING TO EXPIRE. SURFACE
HIGH PRESSURE BUILDING INTO THE OHIO RIVER VALLEY THIS AFTERNOON
WILL CAUSE WINDS TO VEER SOUTHWESTERLY BY THIS EVENING. WARM
ADVECTION PATTERN WILL KEEP WINDS IN THE 10 TO 20 KNOT RANGE. THE
NEXT CHANCE FOR NOTABLE MARINE WEATHER WILL BE SUNDAY EVENING AS
ANOTHER COLD AIRMASS WILL SWEEP ACROSS THE RELATIVELY WARMER WATERS.
RIGHT NOW...IT APPEARS THAT HIGH END WIND GUSTS SUNDAY NIGHT WILL
REMAIN 30 KNOTS OR LESS.
&&
.AVIATION...ISSUED 1144 PM EST THU JAN 31 2013
//DISCUSSION...
THE COVERAGE AND INTENSITY OF LAKE EFFECT SNOW SHOWERS WILL DIMINISH
DURING THE EARLY MORNING HOURS...WITH THE HIGHER INTENSITY SNOW
BANDS SHIFTING SOUTH OF THE TERMINALS AS THE LOW LEVEL FLOW VEERS
TOWARD THE W-NW. THE FLOW WILL BACK MORE TOWARD THE W-SW FRI
AFTERNOON. INVERSION HEIGHTS WILL BE MUCH LOWER AND THE AMBIENT
AIRMASS DRIER...SO JUST A FEW FLURRIES ARE EXPECTED.
FOR DTW...THE BAND OF HEAVIER SNOW WILL PUSH SOUTH OF THE AIRPORT BY
06 OR 07Z. AFTER WHICH...MAINLY FLURRIES OR LIGHT SNOW SHOWERS WILL
LITTLE TO NO ADDITIONAL ACCUMULATIONS EXPECTED.
//DTW THRESHOLD THREATS...
* MEDIUM CONFIDENCE IN CEILING BELOW 5000 FT THROUGH THE TAF
PERIOD.
&&
.DTX WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LAKE HURON...NONE.
LAKE ST CLAIR...NONE.
MI WATERS OF LAKE ERIE...NONE.
&&
$$
SHORT TERM...CB
LONG TERM....DRK
MARINE.......CB
AVIATION.....SC
YOU CAN OBTAIN YOUR LATEST NATIONAL WEATHER SERVICE FORECASTS ONLINE
AT WWW.WEATHER.GOV/DETROIT (ALL LOWER CASE).
AREA FORECAST DISCUSSION...UPDATED
NWS ST LOUIS MO
745 PM CST SAT FEB 2 2013
.UPDATE...
ISSUED AT 745 PM CST SAT FEB 2 2013
STRONG UPPER LEVEL DISTURBANCE...CLIPPER SYS...IS RACING TOWARDS
THE FA THIS EVENING. HEADING TOWARDS THE SFC...THERE IS ALSO AN
ACCOMPANYING FRONTAL SYS WITH THIS...IN THE FORM OF A WEAK LO PRES
STRAGGLING BEHIND IT AND A WRMFNT EXTENDING SWD AND A CDFNT
EXTENDING WWD.
THE CLIPPER SYS UPPER LEVEL PORTION IS SPLIT INTO TWO SECTIONS...
THE NRN PART OVER N-CNTRL IA...WHILE THE SRN PART IS OVER SWRN IA.
HRRR AND RAP DEVELOP THE SRN PART MORE EXTENSIVELY WITH TIME AND
EVENTUALLY THIS SHOULD BECOME THE DOMINANT PART AND WATCHING
DEVELOPMENT OF PCPN IN IA SEEMS TO BE CONFIRMING THIS. THEREFORE
IT LOOKS LIKE PCPN AXIS NEEDS TO BE SHIFTED MORE SWWD FOR THIS
STORM AS IT MOVES THRU THE FA...FROM NEAR MEXICO MO THRU THE STL
METRO AREA AND INTO SRN IL. NOT TO SAY IT WON/T PRECIPITATE
FURTHER NEWD...AS BROAD AREA SHOULD REMAIN LARGELY INTACT AS IT
MOVES THRU...BUT BETTER POTENTIAL FOR MORE DYNAMICALLY INDUCED
BANDS THRU THE AFOREMENTIONED AREAS THOUGH.
HOWEVER...UNFORTUNATELY...IT LOOKS LIKE PCPN-TYPE WILL NOT BE ALL
SNOW ON THE SWRN EDGE WHERE WE COULD SEE SOME BETTER BANDING. RAP
SOUNDINGS AS WELL AS NAM SUGGEST LO-ELEVATED WARM WEDGE OF AIR
AROUND 2-3KFT THAT WILL BE LOOSELY TIED TO THE SFC-TEMP IN THAT IT
SHOULD BE NEAR ISOTHERMAL BUT ENOUGH TO RESULT IN SOME SLEET AND
RAIN POTENTIAL AS WELL BUT ONLY ALONG THE EXTREME SWRN EDGE.
ELSEWHERE SHOULD BE MOSTLY IF NOT ALL SNOW.
UPDATED SNOW TOTALS REFLECT A MORE SWWD SHIFT...AND WILL SEE
WIDESPREAD HALF INCH TO INCH TOTALS FA-WIDE EXCEPT IN CNTRL AND
SERN MO. WHERE MESOSCALE BANDS SETUP...AND FALL AS SNOW...COULD
SEE OVER AN INCH...PERHAPS TWO. BUT TOO DIFFICULT TO NAIL DOWN
JUST YET.
SFC WRMFNT WILL THEN PUSH THRU LATER TONIGHT AND RESULT IN NEAR-
STEADY OR SLOWLY RISING TEMPS BUT THEN FOLLOWED BY CDFNT WHEREBY
WINDS WILL PICK UP AND BECOME GUSTY TO 25-30MPH AND WILL LAST THRU
SUNDAY MORNING BEFORE DIMINISHING.
TES
&&
.SHORT TERM...
ISSUED AT 329 PM CST SAT FEB 2 2013
(TONIGHT)
LAST NIGHT/S SYSTEM MOVED OUT FAIRLY QUICKLY...NOW NEXT IN A SERIES
OF SHORTWAVES TO SLIDE SOUTHEAST THROUGH FORECAST AREA TONIGHT.
CLOUDS ALREADY ON INCREASE WITH REGIONAL RADARS SHOWING MAIN AREA OF
SNOW ALREADY DEVELOPING OVER EASTERN SOUTH DAKOTA AND WESTERN MN...
TRACKING TO THE SOUTHEAST. SHOULD BEGIN TO MOVE INTO NORTHERN
PORTIONS OF FORECAST AREA BY 01Z AND QUICKLY SPREAD ACROSS FORECAST
AREA...WITH BEST CHANCES OVER EASTERN MO AND CENTRAL/SOUTHERN IL
THIS EVENING...THEN TAPER OFF AFTER MIDNIGHT. WITH MODELS IN GOOD
AGREEMENT ON STRENGTH...PLACEMENT AND TIMING OF THIS VIGOROUS
SHORTWAVE...UPPED POPS TO LIKELY FOR NORTHEAST/EAST CENTRAL MO AS
WELL AS WEST CENTRAL ILLINOIS. IT WILL BE A QUICK SHOT OF SNOW WITH
UP TO AN INCH POSSIBLE EAST OF MISSISSIPPI RIVER WITH A FAIRLY SHARP
CUTOFF ON SNOW VS NO SNOW TO THE WEST. AS SNOW TAPERS OFF...CLOUDS
TO BEGIN CLEARING OUT FROM WEST TO EAST TOWARDS DAYBREAK. AS FOR
LOWS TONIGHT...LOW 20S NORTHEAST PORTIONS TO UPPER 20S OVER CENTRAL
AND SOUTHEASTERN MISSOURI.
BYRD
&&
.LONG TERM...
ISSUED AT 329 PM CST SAT FEB 2 2013
(SUNDAY-THURSDAY)
UA PATTERN IS FORECAST BY ALL SOLUTIONS TO TRANSITION TO A ZONAL
FLOW REGIME OVER THE CENTRAL CONUS BY MIDWEEK...HOWEVER STRONG FLOW
ALOFT WILL CONTINUE THE PARADE OF FAST MOVING WEATHER SYSTEMS ACROSS
THE MID-MISSISSIPPI VALLEY.
TONIGHT`S CLIPPER SYSTEM SHOULD BE WELL EAST OF THE AREA BY 12Z
SUNDAY...WITH N-S SURFACE RIDGE RAPIDLY PRESSING THROUGH AREA SUNDAY
AFTERNOON AND EVENING. IN THE WAKE OF THE HIGH...THE NEXT SHORTWAVE
WILL RACE INTO THE MID MISSISSIPPI VALLEY ON MONDAY...WITH
ASSOCIATED SURFACE LOW AND COLD FRONT WORKING ACROSS THE CWA DURING
THE DAY. MODEL CYCLES EARLIER IN THE WEEK HAD BEEN TRYING TO BRING
THE FRONT THROUGH DRY...BUT LAST NIGHTS 00Z RUNS AND TODAYS 12Z
OUTPUT HAVE BEEN GENERATING CHANCE POPS WITH THIS FEATURE..WHICH
APPEARS REASONABLE GIVEN MOISTURE INCREASE PROGGED INTO AREA TIED TO
UVV WITH SHORTWAVE. HAVE GENERALLY MAINTAINED GOING FORECAST TRENDS
WITH CHANCE POPS OVER ABOUT THE SE HALF OF THE CWA.
THIS SYSTEM RACES EAST ON MONDAY EVENING...FOLLOWED BY ANOTHER
SURFACE RIDGE THAT WILL WORK INTO THE AREA WITH DRY AND TRANQUIL
WEATHER ON TUESDAY AND WEDNESDAY.
MEDIUM RANGE SOLUTIONS REMAIN IN FAIRLY GOOD AGREEMENT WITH THE
APPROACH OF THE NEXT SHORTWAVE ON THURSDAY...AND HAVE CONTINUED
CHANCE POPS ACROSS THE ENTIRE CWA WITH THIS FEATURE.
MODERATION OF AMS OVER REGION AS A RESULT OF THE TRANSITION OF THE
UA PATTERN SHOULD MEAN TEMPERATURES AT OR ABOVE AVERAGE FOR MUCH OF
THE PERIOD. ALTHOUGH A BRIEF SHOT OF COOL AIR BEHIND TONIGHT`S
CLIPPER MAY DELAY THIS MODERATION HIGHS SHOULD BE WELL IN THE 40S
MONDAY-WEDNESDAY...WITH S SECTIONS OF THE CWA CLIMBING INTO THE 50S
BY THURSDAY.
(FRIDAY-SATURDAY)
HEADING INTO THE END OF THE WEEK...ATTENTION TURNS TO STRONG STORM
SYSTEM THAT WILL BE MOVING FROM THE WESTERN U.S. INTO THE CENTRAL
PLAINS. WHILE THERE ARE SOME DIFFERENCES...MEDIUM RANGE GUIDANCE IS
SIMILAR ENOUGH WITH SPEED OF THIS SYSTEM TO WARRANT INCLUSION OF
POPS BY SATURDAY. WITH SURFACE LOW PROGGED THROUGH THE CENTRAL
PLAINS WE WILL BE ON THE WARM SIDE OF THE SYSTEM...SO PTYPE WILL BE
RAIN.
TRUETT
&&
.AVIATION...
ISSUED AT 540 PM CST SAT FEB 2 2013
LIGHT SNOW IS EXPECTED FOR A FEW HOURS TONIGHT AS A CLIPPER SYSTEM
MOVES ACROSS THE AREA. INITIALLY VFR CIGS WILL FALL TO MVFR WITH
THE ONSET OF PCPN HOWEVER SATELLITE IMAGERY DOES SHOW SOME SMALL
RAGGED LOOKING PATCHES OF MVFR CLOUDS UPSTREAM AND AHEAD OF THE
SNOW SO I CANNOT RULE OUT A BRIEF PD OF MVFR CIGS BEFORE PCPN
BEGINS. CIGS WILL CLEAR TOMORROW MORNING AS THE SFC HIGH BUILDS IN
TO THE REGION. BUFKIT SOUNDINGS AND UPSTREAM OBS SUPPORT GUSTY NW
WINDS TOMORROW MORNING AND EARLY AFTN. GUSTS SHOULD DIMINISH
DURING THE MID TO LATE AFTN HOURS DUE TO WEAKENING WINDS ALOFT.
SUSTAINED WINDS WILL ALSO DECREASE ONCE THE SFC PRESSURE GRADIENT
BEGINS TO WEAKEN.
SPECIFICS FOR KSTL...LIGHT SNOW IS EXPECTED FOR A FEW HOURS
TONIGHT AS A CLIPPER SYSTEM MOVES ACROSS THE AREA. INITIALLY VFR
CIGS WILL FALL TO MVFR WITH THE ONSET OF PCPN HOWEVER SATELLITE
IMAGERY DOES SHOW SOME SMALL RAGGED LOOKING PATCHES OF MVFR CLOUDS
UPSTREAM AND AHEAD OF THE SNOW SO I CANNOT RULE OUT A BRIEF PD OF
MVFR CIGS BEFORE PCPN BEGINS. CIGS WILL CLEAR TOMORROW MORNING AS
THE SFC HIGH BUILDS IN TO THE REGION. BUFKIT SOUNDINGS AND
UPSTREAM OBS SUPPORT GUSTY NW WINDS TOMORROW MORNING AND EARLY
AFTN. GUSTS SHOULD DIMINISH DURING THE MID TO LATE AFTN HOURS DUE
TO WEAKENING WINDS ALOFT. SUSTAINED WINDS WILL ALSO DECREASE ONCE
THE SFC PRESSURE GRADIENT BEGINS TO WEAKEN.
KANOFSKY
&&
.LSX WATCHES/WARNINGS/ADVISORIES...
MO...NONE.
IL...NONE.
&&
$$
WFO LSX
AREA FORECAST DISCUSSION
NWS NORTH PLATTE NE
1223 PM CST FRI FEB 1 2013
.AVIATION...
SURFACE WARM FRONT PUSHES EAST ACROSS THE AREA THIS
AFTERNOON...MEANWHILE A WEAK UPPER LEVEL DISTURBANCE SLIDES
SOUTHEAST ACROSS THE AREA. DRY LOW LEVELS SHOULD RESULT IN LITTLE
IF ANY PRECIP REACHING THE GROUND THIS AFTERNOON...HOWEVER DO
EXPECT AN INCREASE OF MID AND UPPER LEVEL CLOUDS. OVERNIGHT AS
TEMPS COOL A BETTER CHANCES INCREASE FOR PRECIP TO REACH THE
GROUND. TEMPS CLOSER TO FREEZING WITH A RAIN/SNOW MIX OR ALL LIGHT
SNOW EVENT ANTICIPATED. HAVE INCLUDED A TEMPO FOR SNOW FOR
KVTN...HOWEVER HAVE KEPT SNOW OUT OF KLBF DUE TO LACK OF
CONFIDENCE THE DRY LOWER LEVELS WILL BE OVERCOME WHERE LIFT IS
WEAKER. BY MORNING THE WAVE WILL EXIT WITH DECREASING CLOUDS.
&&
.PREV DISCUSSION... /ISSUED 348 AM CST THU JAN 31 2013/
DISCUSSION...
SHORT TERM...THROUGH 12Z MONDAY. EVENING UPPER AIR ANALYSIS REVEALS
A BROAD TROUGH OVER THE EASTERN CONUS...WITH RIDGING ACROSS THE
WEST. IN-BETWEEN...PROGRESSIVE NORTHWESTERLY FLOW PREVAILS OVER
MUCH OF THE PLAINS REGION...WITH AREA RAOBS INDICATING FAIRLY STRONG
MID-LEVEL ENERGY OF 90KTS OR GREATER. AT THE SURFACE...HIGH
PRESSURE HAS SETTLED OVER THE MISSOURI VALLEY...WITH A
QUASI-STATIONARY FRONT WAFFLING ALONG THE WYOMING/NEBRASKA BORDER.
THE KLNX RADAR HAS BEEN INTERROGATING LIGHT RETURNS FOR MUCH OF THE
EVENING OVER WESTERN PORTIONS OF THE CWA. THIS ACTIVITY DID PRODUCE
SOME LIGHT SNOW IN ASSOCIATION WITH THE RIGHT-REAR QUADRANT OF THE
JET AND RESULTANT WEAK DIRECT THERMAL CIRCULATION. THE HRRR AND RAP
SEEM TO HAVE A GOOD HANDLE ON THE EARLIER PRECIP...WITH BOTH MODELS
INDICATING DRYING OF THE ATMOSPHERE TOWARD DAWN...THUS WILL NOT
CARRY ANY MENTION OF FLURRIES FROM 12 TO 18Z TODAY. THEREAFTER...A
QUICK MOVING SHORTWAVE WILL DROP THROUGH THE REGION THIS
AFTERNOON/EVENING AND BRING ADDITIONAL CHANCES OF LIGHT QPF. MODEST
QG ASCENT WILL COMBINE WITH INCREASING ATMOSPHERIC MOISTURE TO
SQUEEZE OUT SOME SPRINKLES AND/OR FLURRIES THIS AFTERNOON AND
THROUGH THE EVENING. MODEL GUIDANCE IS ALL OVER THE PLACE WITH THE
QPF...SO GENERALLY USED A BROAD-BRUSH APPROACH ACROSS THE CWA WITH
THE FLURRIES/SPRINKLES...BUT MAINTAINED HIGHER CHANCES ACROSS THE
NORTH /LATE/ AND SOUTHWEST WHERE THE BETTER LIFT/MOISTURE IS
EXPECTED. OTHERWISE FOR TODAY WARM AIR ADVECTION WILL SWEEP ACROSS
THE CWA EARLY...WITH HIGHS WARMING SOME 10-20 DEGREES. INCREASING
CLOUDS MAY HAMPER FULL WARMING POTENTIAL...WILL UNDERCUT GUIDANCE BY
A DEGREE OR TWO. NORTHWESTERLY FLOW ALOFT REMAINS ACROSS THE
NORTHERN AND CENTRAL PLAINS THROUGH THE WEEKEND...WITH TEMPERATURES
MODERATING A FEW DEGREES EACH DAY. THERE ARE DIFFERENCES BETWEEN
THE NAM AND GFS WITH THE HANDLING OF THE NEXT SHORTWAVE PASSAGE ON
SATURDAY...THE NAM IS THE FURTHEST WEST WITH THE FEATURE...BUT BOTH
HAVE THE PASSAGE EAST OF THE MISSOURI BASIN THOUGH...SO WILL LEAVE
THE FORECAST DRY...ESPECIALLY SINCE MOISTURE IS SHOWN TO BE LACKING.
EXTENDED...12Z MONDAY AND BEYOND. ADDITIONAL SHORTWAVE ENERGY IS
INDICATED TO PASS THROUGH THE REGION MONDAY...TUESDAY AND
WEDNESDAY...BUT AGAIN THE BEST FORCING WITH EACH WAVE REMAINS WELL
REMOVED OF THE REGION...THUS THE EXTENDED FORECAST TO REMAIN DRY.
INTRUSIONS OF ARCTIC AIR WILL SPILL SOUTH FROM CANADA WITH EACH
SUCCESSIVE WAVE...BUT THE BRUNT OF THE ARCTIC AIR WILL BE EAST
AND NORTH OF THE FORECAST AREA. HIGH TEMPERATURES SHOULD REMAIN IN
THE 40S AND LOW 50S FOR MUCH OF THE CWA THROUGH MID-WEEK. BEYOND
MIDWEEK...THE UPPER PATTERN BEGINS TO BECOME MORE ZONAL IN
NATURE...AS THE WESTERN RIDGE BREAKS DOWN. BY WEEKS END...A
SIGNIFICANT TROUGH DEVELOPS OVER THE WESTERN CONUS...WHICH WILL
PLACE US UNDER SOUTHWESTERLY FLOW ALOFT AS EARLY AS FRIDAY...BUT
DIFFERENCES BETWEEN THE LONG RANGE SOLUTIONS WILL PRECLUDE ANY MAJOR
CHANGES OR ADDITIONS TO THE EXTENDED FORECAST BEYOND WEDNESDAY.
&&
.LBF WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
AVIATION...MASEK
AREA FORECAST DISCUSSION
NWS NORTH PLATTE NE
534 AM CST FRI FEB 1 2013
.AVIATION...
FOR THE NORTH PLATTE AND VALENTINE TERMINALS THROUGH 12Z SATURDAY.
EXPECT MOSTLY CLOUDY SKIES TODAY AND TONIGHT ACROSS MOST OF WESTERN
AND NORTH CENTRAL NEBRASKA...WITH ABUNDANT MID AND HIGH LEVEL
CLOUDINESS EXPECTED TODAY...AND LOW TO MID LEVEL CLOUD COVER
POSSIBLE TONIGHT. AN UPPER LEVEL DISTURBANCE WILL TRACK FROM THE
DAKOTAS INTO NORTHERN AND EASTERN NEBRASKA THIS AFTERNOON AND EVENING. AS
THIS FEATURE APPROACHES...ABUNDANT MID LEVEL CLOUDINESS WILL DEVELOP
THIS AFTERNOON. CIGS WILL POSSIBLY LOWER TO MVFR LEVELS AT THE KVTN
TERMINAL EARLY THIS EVENING. IN ADDITION...LIGHT SNOW IS POSSIBLE
FRIDAY EVENING...ESPECIALLY OVER NORTHERN NEBRASKA. VSBYS DOWN TO 3
TO 5 SM ARE POSSIBLE IN ANY AREAS OF LIGHT SNOW...ESPECIALLY AT THE
KVTN TERMINAL. FURTHER SOUTH AT THE KLBF TERMINAL...MID LEVEL LIFT
IS VERY WEAK SO THE THREAT FOR SNOW IS EXPECTED TO BE MINIMAL.
ACROSS NORTHERN NEBRASKA...LIGHT SNOW AND MVFR CIGS WILL END
OVERNIGHT...HOWEVER...OVERCAST VFR SKIES WILL CONTINUE INTO SATURDAY
MORNING.
&&
.PREV DISCUSSION... /ISSUED 348 AM CST THU JAN 31 2013/
DISCUSSION...
SHORT TERM...THROUGH 12Z MONDAY. EVENING UPPER AIR ANALYSIS REVEALS
A BROAD TROUGH OVER THE EASTERN CONUS...WITH RIDGING ACROSS THE
WEST. IN-BETWEEN...PROGRESSIVE NORTHWESTERLY FLOW PREVAILS OVER
MUCH OF THE PLAINS REGION...WITH AREA RAOBS INDICATING FAIRLY STRONG
MID-LEVEL ENERGY OF 90KTS OR GREATER. AT THE SURFACE...HIGH
PRESSURE HAS SETTLED OVER THE MISSOURI VALLEY...WITH A
QUASI-STATIONARY FRONT WAFFLING ALONG THE WYOMING/NEBRASKA BORDER.
THE KLNX RADAR HAS BEEN INTERROGATING LIGHT RETURNS FOR MUCH OF THE
EVENING OVER WESTERN PORTIONS OF THE CWA. THIS ACTIVITY DID PRODUCE
SOME LIGHT SNOW IN ASSOCIATION WITH THE RIGHT-REAR QUADRANT OF THE
JET AND RESULTANT WEAK DIRECT THERMAL CIRCULATION. THE HRRR AND RAP
SEEM TO HAVE A GOOD HANDLE ON THE EARLIER PRECIP...WITH BOTH MODELS
INDICATING DRYING OF THE ATMOSPHERE TOWARD DAWN...THUS WILL NOT
CARRY ANY MENTION OF FLURRIES FROM 12 TO 18Z TODAY. THEREAFTER...A
QUICK MOVING SHORTWAVE WILL DROP THROUGH THE REGION THIS
AFTERNOON/EVENING AND BRING ADDITIONAL CHANCES OF LIGHT QPF. MODEST
QG ASCENT WILL COMBINE WITH INCREASING ATMOSPHERIC MOISTURE TO
SQUEEZE OUT SOME SPRINKLES AND/OR FLURRIES THIS AFTERNOON AND
THROUGH THE EVENING. MODEL GUIDANCE IS ALL OVER THE PLACE WITH THE
QPF...SO GENERALLY USED A BROAD-BRUSH APPROACH ACROSS THE CWA WITH
THE FLURRIES/SPRINKLES...BUT MAINTAINED HIGHER CHANCES ACROSS THE
NORTH /LATE/ AND SOUTHWEST WHERE THE BETTER LIFT/MOISTURE IS
EXPECTED. OTHERWISE FOR TODAY WARM AIR ADVECTION WILL SWEEP ACROSS
THE CWA EARLY...WITH HIGHS WARMING SOME 10-20 DEGREES. INCREASING
CLOUDS MAY HAMPER FULL WARMING POTENTIAL...WILL UNDERCUT GUIDANCE BY
A DEGREE OR TWO. NORTHWESTERLY FLOW ALOFT REMAINS ACROSS THE
NORTHERN AND CENTRAL PLAINS THROUGH THE WEEKEND...WITH TEMPERATURES
MODERATING A FEW DEGREES EACH DAY. THERE ARE DIFFERENCES BETWEEN
THE NAM AND GFS WITH THE HANDLING OF THE NEXT SHORTWAVE PASSAGE ON
SATURDAY...THE NAM IS THE FURTHEST WEST WITH THE FEATURE...BUT BOTH
HAVE THE PASSAGE EAST OF THE MISSOURI BASIN THOUGH...SO WILL LEAVE
THE FORECAST DRY...ESPECIALLY SINCE MOISTURE IS SHOWN TO BE LACKING.
EXTENDED...12Z MONDAY AND BEYOND. ADDITIONAL SHORTWAVE ENERGY IS
INDICATED TO PASS THROUGH THE REGION MONDAY...TUESDAY AND
WEDNESDAY...BUT AGAIN THE BEST FORCING WITH EACH WAVE REMAINS WELL
REMOVED OF THE REGION...THUS THE EXTENDED FORECAST TO REMAIN DRY.
INTRUSIONS OF ARCTIC AIR WILL SPILL SOUTH FROM CANADA WITH EACH
SUCCESSIVE WAVE...BUT THE BRUNT OF THE ARCTIC AIR WILL BE EAST
AND NORTH OF THE FORECAST AREA. HIGH TEMPERATURES SHOULD REMAIN IN
THE 40S AND LOW 50S FOR MUCH OF THE CWA THROUGH MID-WEEK. BEYOND
MIDWEEK...THE UPPER PATTERN BEGINS TO BECOME MORE ZONAL IN
NATURE...AS THE WESTERN RIDGE BREAKS DOWN. BY WEEKS END...A
SIGNIFICANT TROUGH DEVELOPS OVER THE WESTERN CONUS...WHICH WILL
PLACE US UNDER SOUTHWESTERLY FLOW ALOFT AS EARLY AS FRIDAY...BUT
DIFFERENCES BETWEEN THE LONG RANGE SOLUTIONS WILL PRECLUDE ANY MAJOR
CHANGES OR ADDITIONS TO THE EXTENDED FORECAST BEYOND WEDNESDAY.
&&
.LBF WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
SHORT TERM/EXTENDED...JACOBS
AVIATION...CLB
AREA FORECAST DISCUSSION
NWS NORTH PLATTE NE
348 AM CST FRI FEB 1 2013
.DISCUSSION...
SHORT TERM...THROUGH 12Z MONDAY. EVENING UPPER AIR ANALYSIS REVEALS
A BROAD TROUGH OVER THE EASTERN CONUS...WITH RIDGING ACROSS THE
WEST. IN-BETWEEN...PROGRESSIVE NORTHWESTERLY FLOW PREVAILS OVER
MUCH OF THE PLAINS REGION...WITH AREA RAOBS INDICATING FAIRLY STRONG
MID-LEVEL ENERGY OF 90KTS OR GREATER. AT THE SURFACE...HIGH
PRESSURE HAS SETTLED OVER THE MISSOURI VALLEY...WITH A
QUASI-STATIONARY FRONT WAFFLING ALONG THE WYOMING/NEBRASKA BORDER.
THE KLNX RADAR HAS BEEN INTERROGATING LIGHT RETURNS FOR MUCH OF THE
EVENING OVER WESTERN PORTIONS OF THE CWA. THIS ACTIVITY DID PRODUCE
SOME LIGHT SNOW IN ASSOCIATION WITH THE RIGHT-REAR QUADRANT OF THE
JET AND RESULTANT WEAK DIRECT THERMAL CIRCULATION. THE HRRR AND RAP
SEEM TO HAVE A GOOD HANDLE ON THE EARLIER PRECIP...WITH BOTH MODELS
INDICATING DRYING OF THE ATMOSPHERE TOWARD DAWN...THUS WILL NOT
CARRY ANY MENTION OF FLURRIES FROM 12 TO 18Z TODAY. THEREAFTER...A
QUICK MOVING SHORTWAVE WILL DROP THROUGH THE REGION THIS
AFTERNOON/EVENING AND BRING ADDITIONAL CHANCES OF LIGHT QPF. MODEST
QG ASCENT WILL COMBINE WITH INCREASING ATMOSPHERIC MOISTURE TO
SQUEEZE OUT SOME SPRINKLES AND/OR FLURRIES THIS AFTERNOON AND
THROUGH THE EVENING. MODEL GUIDANCE IS ALL OVER THE PLACE WITH THE
QPF...SO GENERALLY USED A BROAD-BRUSH APPROACH ACROSS THE CWA WITH
THE FLURRIES/SPRINKLES...BUT MAINTAINED HIGHER CHANCES ACROSS THE
NORTH /LATE/ AND SOUTHWEST WHERE THE BETTER LIFT/MOISTURE IS
EXPECTED. OTHERWISE FOR TODAY WARM AIR ADVECTION WILL SWEEP ACROSS
THE CWA EARLY...WITH HIGHS WARMING SOME 10-20 DEGREES. INCREASING
CLOUDS MAY HAMPER FULL WARMING POTENTIAL...WILL UNDERCUT GUIDANCE BY
A DEGREE OR TWO. NORTHWESTERLY FLOW ALOFT REMAINS ACROSS THE
NORTHERN AND CENTRAL PLAINS THROUGH THE WEEKEND...WITH TEMPERATURES
MODERATING A FEW DEGREES EACH DAY. THERE ARE DIFFERENCES BETWEEN
THE NAM AND GFS WITH THE HANDLING OF THE NEXT SHORTWAVE PASSAGE ON
SATURDAY...THE NAM IS THE FURTHEST WEST WITH THE FEATURE...BUT BOTH
HAVE THE PASSAGE EAST OF THE MISSOURI BASIN THOUGH...SO WILL LEAVE
THE FORECAST DRY...ESPECIALLY SINCE MOISTURE IS SHOWN TO BE LACKING.
EXTENDED...12Z MONDAY AND BEYOND. ADDITIONAL SHORTWAVE ENERGY IS
INDICATED TO PASS THROUGH THE REGION MONDAY...TUESDAY AND
WEDNESDAY...BUT AGAIN THE BEST FORCING WITH EACH WAVE REMAINS WELL
REMOVED OF THE REGION...THUS THE EXTENDED FORECAST TO REMAIN DRY.
INTRUSIONS OF ARCTIC AIR WILL SPILL SOUTH FROM CANADA WITH EACH
SUCCESSIVE WAVE...BUT THE BRUNT OF THE ARCTIC AIR WILL BE EAST
AND NORTH OF THE FORECAST AREA. HIGH TEMPERATURES SHOULD REMAIN IN
THE 40S AND LOW 50S FOR MUCH OF THE CWA THROUGH MID-WEEK. BEYOND
MIDWEEK...THE UPPER PATTERN BEGINS TO BECOME MORE ZONAL IN
NATURE...AS THE WESTERN RIDGE BREAKS DOWN. BY WEEKS END...A
SIGNIFICANT TROUGH DEVELOPS OVER THE WESTERN CONUS...WHICH WILL
PLACE US UNDER SOUTHWESTERLY FLOW ALOFT AS EARLY AS FRIDAY...BUT
DIFFERENCES BETWEEN THE LONG RANGE SOLUTIONS WILL PRECLUDE ANY MAJOR
CHANGES OR ADDITIONS TO THE EXTENDED FORECAST BEYOND WEDNESDAY.
&&
.AVIATION...
FOR THE NORTH PLATTE AND VALENTINE TERMINALS THROUGH 12Z SATURDAY.
EXPECT MOSTLY CLOUDY SKIES TODAY AND TONIGHT ACROSS MOST OF WESTERN
AND NORTH CENTRAL NEBRASKA...WITH ABUNDANT MID AND HIGH LEVEL
CLOUDINESS EXPECTED TODAY...AND LOW TO MID LEVEL CLOUD COVER
POSSIBLE TONIGHT. AN UPPER LEVEL DISTURBANCE WILL TRACK FROM THE
DAKOTAS INTO NORTHERN AND EASTERN NEBRASKA THIS AFTERNOON AND EVENING. AS
THIS FEATURE APPROACHES...ABUNDANT MID LEVEL CLOUDINESS WILL DEVELOP
THIS AFTERNOON. CIGS WILL POSSIBLY LOWER TO MVFR LEVELS AT THE KVTN
TERMINAL LATE THIS AFTERNOON AND EARLY THIS EVENING. IN
ADDITION...LIGHT SNOW IS POSSIBLE FRIDAY EVENING...ESPECIALLY OVER
NORTHERN NEBRASKA. VSBYS DOWN TO 3 TO 5 SM ARE POSSIBLE IN ANY AREAS OF
LIGHT SNOW...ESPECIALLY AT THE KVTN TERMINAL. FURTHER SOUTH AT THE
KLBF TERMINAL...MID LEVEL LIFT IS VERY WEAK SO THE THREAT FOR SNOW
IS EXPECTED TO BE MINIMAL. ACROSS NORTHERN NEBRASKA...LIGHT SNOW AND
MVFR CIGS WILL END OVERNIGHT...HOWEVER...OVERCAST VFR SKIES WILL
CONTINUE INTO SATURDAY MORNING.
&&
.LBF WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
SHORT TERM/EXTENDED...JACOBS
AVIATION...CLB
AREA FORECAST DISCUSSION
NWS HASTINGS NE
1135 PM CST THU JAN 31 2013
.AVIATION...06Z TAF. KEEPING QUIET WEATHER AND VFR CONDITIONS
GOING IN THE TAF...THOUGH THERE IS A LITTLE MORE UNCERTAINTY AT
THE END OF THE TAF PERIOD WITH WHETHER OR NOT A FEW FLURRIES AND
POTENTIALLY LOWER CEILINGS MOVE INTO THE TERMINAL AREA. A SURFACE
RIDGE AXIS SLIDING THROUGH THE REGION IS BRINGING LIGHT/VARIABLE
WINDS TO THE TERMINAL CURRENTLY...BUT THROUGH THE REST OF THE
OVERNIGHT HOURS...WINDS WILL GRADUALLY BECOME MORE SOUTHERLY AS
THE RIDGE MOVES OFF TO THE EAST. SPEEDS WILL PICK UP A BIT THIS
AFTERNOON...WITH A FEW GUSTS NEAR 20 MPH POSSIBLE...AND THIS
EVENING A FRONTAL BOUNDARY WILL PUSH THROUGH THE TERMINAL
AREA...BRINGING WEST/NORTHWEST WINDS.
&&
.PREV DISCUSSION... /ISSUED 943 PM CST THU JAN 31 2013/
UPDATE...RADAR DATA FROM KUEX...KLNX AND KGLD INDICATE A WEAK
BAND OF PRECIPITATION OVER SOUTHWESTERN NEBRASKA AND NORTHWESTERN
KANSAS...WITH SOME OF THIS ACTIVITY NOW CREEPING INTO EXTREME
SOUTHWESTERN PORTIONS OF OUR CWA. EVENING UPPER AIR ANALYSIS
INDICATES A ~90KT MID LEVEL JET STREAK OVER THE CENTRAL PLAINS
NOW...WITH THE RIGHT-REAR QUADRANT OF THIS JET STREAK MOVING INTO
SOUTHWESTERN NEBRASKA AND NORTHWESTERN KANSAS. THERE APPEARS TO BE
JUST ENOUGH OF A DIRECT THERMAL CIRCULATION AND RESULTANT MID
LEVEL FRONTOGENESIS FOR VERY LIGHT PRECIPITATION PRODUCTION. IT
DOES NOT APPEAR AS THOUGH MUCH OF THIS PRECIPITATION IS MAKING IT
TO THE GROUND HOWEVER AS FORECAST PROXIMITY SOUNDINGS FROM ACROSS
OUR SOUTHWEST...PER THE NAM AND RAP...SUGGEST LOWER TROPOSPHERIC
MOISTURE IS FAIRLY MEAGER. BUT THERE WAS A REPORT OF BRIEF
PRECIPITATION EARLIER THIS EVENING ACROSS EXTREME SOUTHWESTERN
NEBRASKA FROM THIS SAME BAND. THE HRRR SEEMS TO HAVE A GOOD HANDLE
ON THIS SITUATION BY SUGGESTING THIS BAND WILL MEANDER OVER
SOUTHWESTERN PORTIONS OF OUR CWA TONIGHT WHICH MAY PRESENT
PERIODIC SNOW FLURRIES TO THOSE AREAS. AS A RESULT...WENT AHEAD
AND INTRODUCED FLURRIES TO THE FORECAST FOR TONIGHT ACROSS OUR
SOUTHWEST. THE REMAINDER OF THE FORECAST REMAINS IN GREAT
SHAPE...WITH ONLY A FEW MINOR CHANGES MADE TO HOURLY
TEMPERATURE...WIND...DEWPOINT AND SKY GRIDS TO BETTER REFLECT
CURRENT OBSERVATIONS.
PREV DISCUSSION... /ISSUED 407 PM CST THU JAN 31 2013/
SHORT TERM...TONIGHT AND FRIDAY.
WE REMAIN IN NORTHWEST FLOW ALOFT FOR THE SHORT TERM. THE SURFACE
HIGH...CENTERED OVER THE NORTHERN PLAINS WILL SHIFT EAST...PLACING
US WITHIN RETURN FLOW BY THE OVERNIGHT.
TEMPERATURES SHOULD DROP SHARPLY TONIGHT AS WIND DROPS OFF...BUT
STEADY OUT FOR THE OVERNIGHT AS WIND SHIFTS TO THE SOUTH AND
INCREASES A BIT TOWARD DAWN. LOWS WILL LARGELY BE IN THE SINGLE
DIGITS...BUT COULD HAVE BEEN COLDER IF NOT FOR THE RETURN FLOW.
LOOKS LIKE WE ARE JUST FAR ENOUGH SOUTHWEST TO PRECLUDE ANY WIND
CHILL ISSUES...AS WAS THE CASE EARLY THIS MORNING.
MAINLY A TEMPERATURE FORECAST FOR FRIDAY AS SOUTHWEST FLOW FOLLOWS
THE FETCH OF THE SNOW FIELD...WHICH SHOULD HAMPER HIGH TEMPERATURE
WHERE THERE IS SNOW...SO I ESSENTIALLY LOWERED HIGHS OVER THE SNOW
PACK...AND RAISED TEMPERATURES A BIT IN THE NORTHWESTERN
CWA...INCLUDING ORD. SKY COVER WILL INCREASE ESPECIALLY TOWARD
AFTERNOON AS ANOTHER SHORTWAVE TROUGH APPROACHES WITHING NORTHWEST
FLOW. WE WILL BE NEAR THE ENTRANCE REGION OF AN UPPER LEVEL JET
STREAK...WHICH COULD INDUCE SOME FLURRIES IN OUR NORTHERN CWA BY
LATE AFTERNOON..ESPECIALLY NEAR AN UNUSUALLY ORIENTED WARM FRONT
APPROACHING FROM THE WEST. MOST MODELS DO NOT INDICATE ANY SNOW
FLURRY ACTIVITY...BUT THE NMM AND TO SOME EXTENT..THE GFS SHOW THIS
TO BE A POSSIBILITY...SO INCLUDING THIS FOR THE VERY LATE AFTERNOON.
WIND WILL INCREASE FROM THE SOUTH AHEAD OF THE WARM FRONT MOVING IN
FROM THE WEST BY AFTERNOON...BUT AGAIN...THE FETCH OF THE WIND AND
INCREASING CLOUDINESS WILL ROB US ONCE AGAIN OF A POTENTIALLY MORE
MILD DAY FOR THE MAJORITY OF OUR CWA.
LONG TERM...FRIDAY EVENING THROUGH NEXT THURSDAY. FIRST OFF...VERY
FEW NOTICEABLE CHANGES WERE MADE FROM THE PREVIOUS FORECAST...AS THE
MAIN THEME CONTINUES TO BE PRECIPITATION-FREE CONDITIONS WITH THE
POSSIBLE EXCEPTION OF FRIDAY EVENING MAINLY IN THE NORTHEAST...AND
A SEVERAL-DAY STRETCH OF DECENT TEMPERATURES AVERAGING AROUND 10
DEGREES ABOVE NORMAL.
STARTING OFF FRIDAY NIGHT...MAIN CHANGE FROM PREVIOUS FORECAST IS
THE INTRODUCTION OF A CHANCE/SLIGHT CHANCE OF FLURRIES DURING THE
EVENING HOURS MAINLY ACROSS OUR NORTHEAST 1/2...OR ROUGHLY
NORTHEAST OF A LOUP CITY-SUPERIOR LINE. THERE IS GOOD AGREEMENT
AMONGST VARIOUS 12Z MODELS SUCH AS THE NAM/GFS/ECMWF THAT A LOW
AMPLITUDE SHORTWAVE TROUGH WILL PASS EAST-SOUTHEAST OVER THE AREA
THROUGH THE NIGHT...FOCUSED WITHIN THE ENTRANCE REGION OF A 100+KT
JET AT 300MB. ALTHOUGH FORCING IS NOT GREAT WITH THIS WAVE...THERE
APPEARS TO BE INCREASING CHANCES OF AT LEAST LIGHT MEASURABLE SNOW
ALONG AN AXIS FROM NORTHEAST NEB INTO IA. AT THIS POINT...AM
THINKING THAT THESE MEASURABLE CHANCES SHOULD REMAIN JUST
NORTHEAST OF OUR CWA...BUT IT COULD BE A VERY CLOSE CALL
ESPECIALLY PER THE FORECAST REFLECTIVITY OF THE 12Z 4K WRF-NMM...AND
SOMETHING FOR NEXT FEW SHIFTS TO WATCH. IN THE MEANTIME...AT LEAST
WANTED TO GET THE NON-MEASURABLE FLURRY WORDING GOING...AS NAM
FORECAST SOUNDINGS SUGGEST A FAIRLY DEEP SATURATED LAYER ABOVE
850MB. FOR NOW WILL RUN WITH THE THINKING THAT ANY FLURRY
POTENTIAL WILL END ACROSS OUR CWA BY MIDNIGHT AS FORCING PASSES
MORE TO THE EAST. AT THE SURFACE...THE PASSING UPPER WAVE WILL
DRAG A SURFACE TROUGH ACROSS THE CWA THROUGH THE NIGHT...TURNING
BREEZES FROM THE WEST-NORTHWEST AT AROUND 10-15 MPH AS IT PASSES.
OFTEN...TEMPS TEND TO JUMP AT LEAST A FEW DEGREES AS THESE TROUGHS
PASS EVEN IN THE MIDDLE OF THE NIGHT...BUT GIVEN THIS IS STILL 3
PERIODS OUT WILL NOT ADVERTISE A NON-DIURNAL TEMP CURVE AT THIS
TIME. FOR ACTUAL LOWS...MADE LITTLE CHANGE WITH LOW 20S ADVERTISED ALL
AREAS...ALTHOUGH WOULD NOT BE SURPRISED TO SEE SOUTHEAST AREAS
OVER THE DEEPER SNOW COVER TRY DROPPING INTO THE TEENS BEFORE
MIXING BEHIND THE PASSING TROUGH LINE PICKS UP A BIT. ON ONE LAST
FRIDAY NIGHT NOTE...THE SREF VISIBILITY PROGS ARE SUGGESTING SOME
FOG DEVELOPMENT OVER THE MELTING SNOW PACK DURING THE NIGHT...BUT
THINKING THE WESTERLY WINDS BEHIND THE TROUGH AXIS SHOULD PROVE
UNFAVORABLE FOR ANY FOG WORTH MENTIONING.
SATURDAY/SATURDAY NIGHT...CONFIDENCE IS RATHER HIGH IN A DRY 24
HOURS...AS MID LEVEL HEIGHTS START TO RISE A BIT AS MID LEVEL
TROUGHING MOVES OFF THE TO THE EAST. AS IT DOES SO...COULD SEE
ADDITIONAL SNOW BANDS DEVELOP NEAR/MAINLY EAST OF THE IA/NEB BORDER
DURING THE DAY...BUT THIS SHOULD STAY SQUARELY EAST OF OUR CWA. IN
THE LOW LEVELS...WESTERLY WINDS WILL PICK UP A BIT TOWARD BREEZY
TERRITORY DURING THE DAY...WITH SUSTAINED SPEEDS INCREASING TO AT
LEAST 15-20 MPH FOR A FEW HOURS. NEEDLESS TO SAY...THE BATTLE
BETWEEN THIS WARMING DOWNSLOPE FLOW AND THE LINGERING SNOW PACK
ACROSS MAINLY THE SOUTHEAST 1/2 OF THE CWA MAKES FOR A TRICKY AND
SOMEWHAT LOW CONFIDENCE HIGH TEMPERATURE FORECAST. FOR NOW...WILL
KEEP THEME SIMILAR TO PREVIOUS WITH MAINLY UPPER 40S/NEAR 50 WHERE
SNOW IS NONE/MINIMAL...AND ONLY LOW 40S IN SOUTHEAST COUNTIES
WHERE IT IS DEEPER. COULD EASILY SEE SOME 5+ DEGREE ERRORS HERE
DEPENDING ON HOW MUCH EFFECT THE SNOW FIELD HAS. ALTHOUGH NOT AS
STRONG AS DURING THE DAY...PERSISTENT STEADY WESTERLY BREEZES
OVERNIGHT SHOULD AGAIN HOLD LOW TEMPS UP IN THE LOW 20S MOST ALL
AREAS.
SUNDAY/SUNDAY NIGHT...FAIRLY UNEVENTFUL NORTHWEST FLOW ALOFT
CONTINUES...DESPITE A FEW VERY LOW AMPLITUDE SHORTWAVE TROUGHS
PASSING THROUGH THE FLOW. LOOKS AT THIS POINT LIKE ANY PRECIP
SHOULD FOCUS AT LEAST LEAST FEW HUNDRED MILES NORTHEAST AND/OR
SOUTH OF THE CWA. ALTHOUGH TEMPS AT 850MB SHOULD AVERAGE A BIT
WARMER THAN SATURDAY...BREEZES WILL LIKELY BE A BIT LIGHTER AND
MORE FROM THE SOUTHWEST. THE NET RESULT IS ALMOST IDENTICALLY
FORECAST HIGH TEMPERATURES TO SATURDAY IN MOST AREAS...WITH MAINLY
UPPER 40S...EXCEPT SLIGHTLY COOLER MID 40S OVER THE DEEPER SNOW.
MONDAY/MONDAY NIGHT...THE REGION REMAINS UNDER NORTHWEST FLOW
BETWEEN A RIDGE BUILDING OVER THE WESTERN CONUS...AND THE NEXT IN
A PARADE OF CHANNELED SHORTWAVE TROUGHS SLIDING SOUTHEAST OUT OF
CANADA ACROSS THE DAKOTAS/IA. AGAIN...ANY PRECIPITATION ALONG THIS
SHORTWAVE AXIS SHOULD FOCUS AT LEAST A FEW HUNDRED MILES TO OUR
EAST...WHILE WE REMAIN IN THE MILDER AIR ON THE WARMER SIDE OF THE
UPPER JET. HIGH TEMPS FOLLOW CLOSELY TO ALLBLEND MODEL
CONSENSUS...WITH UPPER 40S MOST NEB ZONES AND LOW/MID 50S
SOUTHWEST.
TUESDAY/TUESDAY NIGHT...THE FLOW ALOFT TRANSITIONS MORE ZONAL IN
THE WAKE OF THE VIGOROUS MIDWEST SHORTWAVE TROUGH THAT QUICKLY
DEPARTS TOWARD THE MID-ATLANTIC REGION. WITH LITTLE FORESEEABLE
CHANGE IN THE LOW LEVEL TEMPERATURE FIELDS...HIGH TEMPS ARE
FORECAST VERY SIMILAR TO MONDAY...RANGING FROM MID 40S NORTHEAST
TO LOW 50S SOUTHWEST.
WEDNESDAY/WEDNESDAY NIGHT...THINGS START TO TURN A BIT MORE
INTERESTING ALOFT...AS BOTH THE ECWMF/GFS ARE IN SURPRISINGLY GOOD
AGREEMENT AS A SLOWLY DEEPENING BUT PROGRESSIVE SHORTWAVE TROUGH
DROPS OUT OF THE NORTHERN ROCKIES TOWARD THE NORTHERN/CENTRAL
PLAINS...ABUT AT LEAST FOR NOW OUR LOCAL PRECIP CHANCES APPEAR
QUITE MINIMAL WITH BETTER FORCING/MOISTURE FOCUSING OFF TO OUR
EAST/SOUTHEAST...ALTHOUGH IT COULD BE A CLOSE CALL ESPECIALLY PER
THE GFS. SOMETHING TO WATCH. MODEL CONSENSUS HIGHS ARE YET AGAIN A
NEAR COPY OF THE PREVIOUS FEW DAYS...UPPER 40S NORTHEAST TO MID
50S SOUTHWEST.
THURSDAY...COULD SEE AT LEAST A SLIGHT COOL-DOWN BEHIND A SURFACE
COLD FRONT THAT PASSES THROUGH WEDNESDAY NIGHT...AND ITS VERY
POSSIBLE THAT CURRENTLY FORECAST TEMPS MAINLY IN THE UPPER 40S TO
LOW 50S COULD BE A BIT TOO WARM. ALOFT...THE AFOREMENTIONED UPPER
WAVE STARTS TO PASS EAST/SOUTHEAST DURING THE DAY...PRESUMABLY
KEEPING PRECIP CHANCES QUITE MINIMAL.
LOOKING BEYOND THE OFFICIAL 7-DAY FORECAST PERIOD...THERE ARE
SUGGESTIONS THAT NEXT WEEKEND COULD HOLD OUR NEXT POTENTIALLY
DECENT PRECIP CHANCES...BUT PLENTY TO IRON OUT HERE.
&&
.GID WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
KS...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS NEWPORT/MOREHEAD CITY NC
335 PM EST FRI FEB 1 2013
.SYNOPSIS...
HIGH PRESSURE WILL BUILD OVER THE AREA TONIGHT AND SATURDAY. ANOTHER
COLD FRONT WILL CROSS THE AREA SATURDAY NIGHT FOLLOWED BY HIGH PRESSURE
SUNDAY AND MONDAY. A COLD FRONT WILL APPROACH THE REGION TUESDAY AND
CROSS THE AREA TUESDAY NIGHT. HIGH PRESSURE WILL BUILD OVER THE AREA
WEDNESDAY INTO THURSDAY.
&&
.NEAR TERM /UNTIL 6 AM SATURDAY MORNING/...
AS OF 315 PM FRIDAY...COLD AND VERY DRY AIRMASS CONTINUES TO TAKE
HOLD OVER EASTERN NORTH CAROLINA WITH MOST DEWPOINTS IN THE SINGLE
DIGITS AND TEENS. THIS DRY AIR IS BEING ACCOMPANIED BY GUSTY
WNW/NW WINDS. HIGH PRESSURE CENTERED OVER THE MID MISSISSIPPI
VALLEY WILL BUILD EAST OVER THE CAROLINAS BY LATE TONIGHT. WITH
LOW DEWPOINTS AND CLEAR SKIES...WINDS SHOULD DIMINISH LATE TONIGHT
PER LATEST RAP MODEL WHICH WILL ALLOW MINIMUM TEMPERATURES AREA-
WIDE IN THE UPPER TEENS TO LOWER 20S EXCEPT FOR SOME MIDDLE 20S
ALONG THE OUTER BANKS.
&&
.SHORT TERM /6 AM SATURDAY MORNING THROUGH 6 PM SATURDAY/...
AS OF 320 PM FRIDAY...SATURDAY WILL BEGIN CLEAR AND COLD WITH HIGH
PRESSURE RIDGE AXIS ALMOST OVERHEAD. THE HIGH WILL SHIFT OFFSHORE
DURING THE AFTERNOON ALLOWING FOR A RETURN S/SSW FLOW WITH
INCREASING MOISTURE BELOW 700 MB BY LATE AFTERNOON AND AN INCREASE
IN CLOUDINESS. MAXIMUM TEMPERATURES USING A CONSENSUS BLEND OF
MODELS YIELDS VALUES IN THE LOWER TO MIDDLE 40S AREA-WIDE.
&&
.LONG TERM /SATURDAY NIGHT THROUGH FRIDAY/...
AS OF 230 PM FRI...YESTERDAY THE ECMWF WAS CLEARLY BETTER THAN THE
GFS FOR THE EXTENDED. TODAY THOUGH THE GFS HAS COME INTO MUCH
BETTER AGREEMENT WITH THE ECMWF...SO AM USING A BLEND OF THE TWO
FOR THE EXTENDED PORTION. A BROAD UPPER TROF WILL REMAIN OVER THE
EASTERN HALF OF THE NATION THROUGH TUESDAY NIGHT...BUT THEN A
ZONAL PATTERN BEGINS TO DEVELOP ON WEDNESDAY. THREE SYSTEMS AFFECT
THE FORECAST AREA DURING THIS TIME. THE FIRST IS A FAST- MOVING
FRONT THAT PASSES THROUGH SATURDAY NIGHT. GUIDANCE POPS A BIT
WETTER THAN YESTERDAY WITH MEASURABLE PRECIP FORECAST FOR ALL
AREAS. USING CRITICAL THICKNESSES YIELDS A RAIN/SNOW MIX. DUE TO
THE SPEED OF THE SYSTEM AMOUNTS WILL BE LIGHT AND NO ACCUMULATION
IS EXPECTED. THE 2ND FRONT TUESDAY/TUESDAY NIGHT WILL HAVE LITTLE
MOISTURE TO WORK WITH SO NO PRECIP IS FORECAST WITH THIS ONE. IT
WILL ONLY BRING A WIND SHIFT AND A SLIGHTLY COOLER AIRMASS. THE
BEST CHANCE FOR RAIN WILL COME ON FRIDAY WITH THE APPROACH OF THE
NEXT FRONT. FORECAST SOUNDINGS SHOW RATHER GOOD SUPPLY OF MOISTURE
THIS TIME SO HAVE INCLUDED CHANCE POPS.
&&
.AVIATION /20Z FRIDAY THROUGH WEDNESDAY/...
SHORT TERM /TONIGHT AND SATURDAY/...
AS OF 1250 PM FRIDAY...VFR CONDITIONS ARE EXPECTED THROUGH THE
TAF CYCLE. GUSTY WNW/NW WINDS WILL PERSIST THROUGH LATE AFTERNOON
WITH A FEW GUSTS IN EXCESS OF 30 MPH. AS AXIS OF HIGH PRESSURE
RIDGE SETTLES OVER THE REGION TONIGHT...EXPECT WINDS TO QUICKLY
DIMINISH.
LONG TERM /SATURDAY NIGHT THROUGH WEDNESDAY/...
AS OF 230 PM FRI...VFR THROUGH THE PERIOD. FAST-MOVING FRONT PASSING
THROUGH SATURDAY NIGHT WILL BRING A CHANCE OF A LIGHT RAIN/SNOW
MIX THROUGH LATE SATURDAY EVENING. GUSTY WEST WIND FORECAST ON
SUNDAY AROUND 15-20 KNOTS.
&&
.MARINE...
SHORT TERM /TONIGHT AND SATURDAY/...
AS OF 325 PM FRIDAY...THE PRIMARY CAA SURGE BEHIND THE COLD FRONT
HAS SUBSIDED AS WINDS PEAKED AROUND 15Z OR 16Z. STILL SEEING GUSTS
WELL INTO THE 20S AND WILL KEEP SMALL CRAFT ADVISORY AS IS WITH
THE SOUTHERN WATERS ENDING AT 00Z...THE SOUNDS AT 03Z AND
ELSEWHERE BY 06Z TONIGHT. SEAS ARE GENERALLY 4 TO 6 FEET AT THE
MOMENT AND SHOULD LIKEWISE SUBSIDE PER WAVEWATCH AND LOCAL NWPS
MODEL. WITH AXIS OF RIDGE BUILDING OVER THE WATERS...WINDS AND
SEAS SHOULD DIMINISH WITH WINDS OF 10 KNOTS OR LESS AND SEAS 4
FEET OR LESS EXPECTED BY SATURDAY MORNING.
LONG TERM /SATURDAY THROUGH WEDNESDAY/...
AS OF 230 PM FRI...USED A CONSENSUS BLEND OF THE LATEST RUNS OF THE
GFS AND ECMWF FOR THE EXTENDED MARINE FORECAST. FAST-MOVING COLD
FRONT WILL MOVE OFF THE COAST SATURDAY NIGHT. A BRIEF PERIOD OF
MARGINAL SMALL CRAFT WINDS/SEAS APPEARS LIKELY SUNDAY AFTERNOON
INTO SUNDAY NIGHT. HIGH PRESSURE ALONG WITH A LOOSE PRESSURE
GRADIENT WILL BUILD IN BEHIND THE SYSTEM FOR MONDAY. THE HIGH WILL
NOT LINGER HOWEVER AND IT MOVES OFF TUESDAY. THE NEXT COLD FRONT
WILL MOVE THROUGH TUESDAY AND TUESDAY NIGHT WITH WINDS SHIFTING TO
THE NORTH FOR WEDNESDAY. SMALL CRAFT SEAS ARE FORECAST FOR THE
COASTAL WATERS NORTH OF OREGON INLET BEHIND THE SYSTEM ON
WEDNESDAY.
&&
.FIRE WEATHER...
WHILE RELATIVE HUMIDITY VALUES WILL REMAIN VERY LOW ON
SATURDAY...WINDS WILL SUBSIDE WHICH SHOULD LESSEN THE OVERALL FIRE
DANGER.
&&
.MHX WATCHES/WARNINGS/ADVISORIES...
NC...NONE.
MARINE...SMALL CRAFT ADVISORY UNTIL 10 PM EST THIS EVENING FOR AMZ130-
135.
SMALL CRAFT ADVISORY UNTIL 1 AM EST SATURDAY FOR AMZ150-152-
154.
SMALL CRAFT ADVISORY UNTIL 7 PM EST THIS EVENING FOR AMZ156-
158.
&&
$$
SYNOPSIS...CTC
NEAR TERM...CTC
SHORT TERM...CTC
LONG TERM...HSA
AVIATION...CTC/HSA
MARINE...CTC/HSA
FIRE WEATHER...CTC
AREA FORECAST DISCUSSION...UPDATED
NWS GRAND FORKS ND
920 PM CST SAT FEB 2 2013
.DISCUSSION...
WILL CONTINUE WITH WINTER WX ADV FOR SOME BLOWING SNOW IN THE FAR
SOUTHWESTERN FCST AREA TIL 06Z. STRONGEST OF THE WINDS IN ERN SD
BUT STILL SOME GUSTS NR 30KTS VALLEY CITY TO GWINNER. BUT WINDS
DIMINISHING QUITE SOON LOOKING UPSTREAM AS PRESSURE RISE MOVES
INTO SW MINNESOTA. OTHERWISE...AREA OF CLEARING MOVING SOUTHEAST
INTO PARTS OF SE ND ATTM BUT CLOUDS IN CANADA MOVING BACK SOUTH
AND WOULD APPEAR CLEARING IN SE ND WILL NOT LAST LONG AND MOST
AREAS TO REMAIN RATHER CLOUDY OVERNIGHT. EXCEPTION IS FAR
NORTHEASTER FCST AREA WHERE CLEARING OVER ERN MB/NW ONT NORTH OF
FLAG ISLAND MAY DROP SOUTH BY 12Z. KEPT THAT AREA STILL NR -10F
FOR LOWS TONIGHT OTHERWISE UPPED LOWS MOST AREAS TO STAY GENERALLY
5 BELOW TO 5 ABOVE. WIND CHILLS SHOULD NOT GET INTO ADV CRITERIA.
&&
.PREV DISCUSSION... /ISSUED 707 PM CST SAT FEB 2 2013/
DISCUSSION...
SFC LOW AT 0030Z JUST PAST WATERTOWN SD. MAIN WIND BELT HAS BEEN
FROM MINOT-WILLISTON THROUGH BISMARCK TO ABERDEEN TO WATERTOWN AS
MOST AREAS EXPERIENCED WINDS IN THE 40-50 MPH FOR A TIME. THE
STRONGER NORTHWEST WINDS HAVE BEEN EVER SO SLOWLY EDGING EASTWARD
BUT AT THE SAME TIME THE MAIN PRESSURE RISE IS MOVING SOUTHEAST
AWAY FROM OUR REGION. THUS EXPECT ONLY REAL ISSUE WITH WIND SPEEDS
30KTS OR SO WILL BE VALLEY CITY-LISBON-GWINNER AREAS WHILE THE
REST OF ERN ND TO SEE SEE WINDS IN THE 10 TO 20 KT RANGE. THUS
DROPPED THE WINTER WX ADV FOR DVL REGION AND FOR WILKIN CO MN AS
MAIN WINDS TO STAY WEST OF THE RED RIVER. DID CONTINUE MENTION OF
-SN AND FLURRIES THRU MIDNIGHT IN MANY AREAS. SOME CLEARING MOVING
INTO CNTRL ND THIS EVE CLOSER TO MAIN SFC HIGH BUT ALSO QUITE A
BIT OF CLOUDS UPSTREAM IN MANITOBA SO UNSURE HOW MUCH CLEARING
WILL GET EAST INTO ERN ND BEFORE CLOUDS MAY DROP BACK IN. NW MN
ESP LOOKS IFFY FOR MUCH CLEARING. WITH PERHAPS MORE CLOUDINESS
OVERNIGHT DID RAISE LOW TEMPS A BIT IN NE ND/NW MN AND WITH PROG
WINDS WIND CHILLS TO STAY IN THE -20 TO -25 RANGE AND OUT OF
ADVISORY RANGE.
AVIATION...
EXPECT A WIND SHIFT ENTER THE RED RIVER VALLEY IN THE 01Z-03Z
PERIOD MOSTLY IN THE 10 TO 20 KT RANGE... LIGHT SNOW AND LOW END
VFR AND PATCHY MVFR CIGS TO PERSIST TIL 06Z AND THEN BE MOSTLY VFR
AREA WIDE.
PREV DISCUSSION... /ISSUED 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.
&&
.FGF WATCHES/WARNINGS/ADVISORIES...
ND...WINTER WEATHER ADVISORY UNTIL MIDNIGHT CST TONIGHT FOR NDZ038-
049-052-053.
MN...NONE.
&&
$$
RIDDLE
AREA FORECAST DISCUSSION...UPDATED
NWS GRAND FORKS ND
707 PM CST SAT FEB 2 2013
.DISCUSSION...
SFC LOW AT 0030Z JUST PAST WATERTOWN SD. MAIN WIND BELT HAS BEEN
FROM MINOT-WILLISTON THROUGH BISMARCK TO ABERDEEN TO WATERTOWN AS
MOST AREAS EXPERIENCED WINDS IN THE 40-50 MPH FOR A TIME. THE
STRONGER NORTHWEST WINDS HAVE BEEN EVER SO SLOWLY EDGING EASTWARD
BUT AT THE SAME TIME THE MAIN PRESSURE RISE IS MOVING SOUTHEAST
AWAY FROM OUR REGION. THUS EXPECT ONLY REAL ISSUE WITH WIND SPEEDS
30KTS OR SO WILL BE VALLEY CITY-LISBON-GWINNER AREAS WHILE THE
REST OF ERN ND TO SEE SEE WINDS IN THE 10 TO 20 KT RANGE. THUS
DROPPED THE WINTER WX ADV FOR DVL REGION AND FOR WILKIN CO MN AS
MAIN WINDS TO STAY WEST OF THE RED RIVER. DID CONTINUE MENTION OF
-SN AND FLURRIES THRU MIDNIGHT IN MANY AREAS. SOME CLEARING MOVING
INTO CNTRL ND THIS EVE CLOSER TO MAIN SFC HIGH BUT ALSO QUITE A
BIT OF CLOUDS UPSTREAM IN MANITOBA SO UNSURE HOW MUCH CLEARING
WILL GET EAST INTO ERN ND BEFORE CLOUDS MAY DROP BACK IN. NW MN
ESP LOOKS IFFY FOR MUCH CLEARING. WITH PERHAPS MORE CLOUDINESS
OVERNIGHT DID RAISE LOW TEMPS A BIT IN NE ND/NW MN AND WITH PROG
WINDS WIND CHILLS TO STAY IN THE -20 TO -25 RANGE AND OUT OF
ADVISORY RANGE.
&&
.AVIATION...
EXPECT A WIND SHIFT ENTER THE RED RIVER VALLEY IN THE 01Z-03Z
PERIOD MOSTLY IN THE 10 TO 20 KT RANGE... LIGHT SNOW AND LOW END
VFR AND PATCHY MVFR CIGS TO PERSIST TIL 06Z AND THEN BE MOSTLY VFR
AREA WIDE.
&&
.PREV DISCUSSION... /ISSUED 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.
&&
.FGF WATCHES/WARNINGS/ADVISORIES...
ND...WINTER WEATHER ADVISORY UNTIL MIDNIGHT CST TONIGHT FOR NDZ038-
049-052-053.
MN...NONE.
&&
$$
RIDDLE/JR
AREA FORECAST DISCUSSION
NWS GRAND FORKS ND
949 AM CST FRI FEB 1 2013
.DISCUSSION...
BUMPED UP POPS FOR THE REST OF THE DAY. OBS AT VALLEY CITY AND
COOPERSTOWN SHOW SNOW HAS ALREADY STARTED TO MOVE INTO THE
SOUTHWESTERN COUNTIES...AND WEB CAMS CONFIRM SOME LIGHT SNOW
BEGINNING TO FALL. RAP AND NAM ARE IN PRETTY GOOD AGREEMENT ON
THIS SNOW BAND MOVING INTO OUR SOUTHEASTERN COUNTIES BY THIS
AFTERNOON. VIS HAVE NOT GONE TERRIBLY LOW SO THINK THAT ANY
ACCUMULATIONS WILL BE VERY LIGHT AND REMAIN UNDER AN INCH. SNOW
WILL BEGIN TO TAPER OFF BY THIS EVENING.
AS FOR TEMPERATURES/WIND CHILLS...ADJUSTED HOURLY TEMPS AS
READINGS IN THE WEST HAVE STARTED TO RISE A BIT FASTER THAN
EXPECTED. WITH SOUTHERLY WINDS KICKING IN THE WESTERN COUNTIES
SHOULD SEE SOME TEMPS GOING UP ABOVE ZERO BY THIS AFTERNOON. A FEW
OF THE WIND CHILLS THIS MORNING IN ISOLATED SPOTS HAVE BEEN AROUND
40 BELOW...BUT THE BITTER COLD WILL BE VERY SHORT LIVED AS TEMPS
BEGIN TO RISE SO WILL JUST KEEP THE ADVISORY AS GOING. WILL HAVE
TO WATCH IN CASE TEMPS ARE SLOWER TO RISE THAN EXPECTED...BUT FOR
NOW PLAN ON LETTING THE WIND CHILL ADVISORY EXPIRE ON TIME AT 18Z.
&&
.AVIATION...
LOW VFR DECK MOVING SOUTHEASTWARD FROM CENTRAL ND TO REACH KFAR LATE
MORNING...TRENDING TO MVFR CIGS AT VALLEY SITES THIS
AFTERNOON...REACHING KBJI THIS EVENING. -SN MOST LIKELY RESTRICTED
TO KFAR ARRIVING EARLY AFTERNOON. LIGHT SOUTH TO SOUTHWEST WINDS
WILL SHIFT TO NORTHWEST LATER TODAY KDVL AND TONIGHT AT OTHER
LOCATIONS.
&&
.PREV DISCUSSION... /ISSUED 430 AM CST FRI FEB 1 2013/
SHORT TERM...TODAY THROUGH SUNDAY NIGHT.
UPPER LEVEL RIDGE WAS LOCATED OVER THE WESTERN NORTH AMERICA AND A
TROUGH WAS LOCATED OVER EASTERN CANADA AND THE NORTHEAST US. UPPER
AIR PATTERN DEAMPLIFIES THIS PERIOD. GFS IS A LITTLE FASTER THAN THE
ECMWF. WILL PREFER THE GFS. WATER VAPOR LOOP INDICATED A SHORT WAVE
OVER MT. SHORT WAVE WILL MOVE ACROSS SD AND NE THIS AFTERNOON AND
TONIGHT.
THERMAL BOUNDARY WILL REMAIN ACROSS THE FORECAST AREA THROUGH MUCH
OF THE PERIOD. SHORT WAVES WILL MOVE THROUGH THE FLOW AND PRODUCE
PERIODS OF LIGHT SNOW. WILL SPEED UP PRECIP MOVING INTO THE AREA
THIS AFTERNOON AND SLOW IT DOWN FOR TONIGHT. RESPECTABLE SHORT WAVE
MOVES THROUGH SAT AND SAT EVENING AND A BETTER CHANCE FOR SNOW. GFS
AND ECMWF HAVE BEEN SHIFTING PRECIP FARTHER WEST WITH EACH RUN. SO
WILL SHIFT PRECIP FARTHER WEST SUN NIGHT. ALSO WILL LOWER TEMPS FOR
SAT AND SUN.
WIND CHILLS OVER THE WESTERN ZONES HAVE TEMPERED MOSTLY TO WIND
CHILL CRITERIA AND SO HAVE REPLACED WIND CHILL WARNING WITH WIND
CHILL ADVISORY THROUGH NOON TODAY.
LONG TERM...MONDAY THROUGH THURSDAY NIGHT
00 UTC GFS/ECMWF IN GOOD AGREEMENT NEXT WEEK...BOTH SHOWING A COUPLE
CLIPPER SYSTEMS MOVING ACROSS THE NORTHERN PLAINS IN NORTHWEST FLOW
ALOFT. THE FIRST WAVE MOVES THROUGH MONDAY NIGHT AND THE SECOND
WEDNESDAY NIGHT. BEST CHANCE FOR MEASURABLE SNOW WILL BE MONDAY AND
MONDAY NIGHT FROM THE DEVILS LAKE BASIN INTO NORTHWEST MN AS A
WELL-DEFINED BAROCLINIC ZONE SETS-UP ACROSS THE FORECAST AREA.
STRONG 850 HPA WARM AIR ADVECTION...COMBINED WITH THE LEFT-EXIT
REGION OF A 125 KT 300 HPA JET STREAK AND SURFACE MIXING RATIOS
AROUND 2 G/KG SHOULD RESULT IN AT LEAST A FEW INCHES ACCUMULATION.
DYNAMIC SUPPORT FOR WEDNESDAY NIGHT/S WAVE NOT AS IMPRESSIVE...SO
WILL KEEP POPS MAINLY IN THE 20S.
SOUTHWEST TO NORTHEAST TEMPERATURE GRADIENT MONDAY/TUESDAY WILL
RESULT IN DAYTIME HIGHS FROM THE LOW 20S ACROSS SOUTHEAST ND TO THE
LOW TO MID TEENS ACROSS THE LAKE OF THE WOODS. THERMAL PROFILE
INCREASES WEDNESDAY/THURSDAY AS WEST COAST RIDGE MOVES OVERHEAD...
SO EXPECT HIGHS IN THE LOW TO MID 20S REGION-WIDE. AFTER MONDAY
MORNING...NIGHTTIME LOWS SHOULD REMAIN ABOVE ZERO THROUGH THE
PERIOD.
&&
.FGF WATCHES/WARNINGS/ADVISORIES...
ND...WIND CHILL ADVISORY UNTIL NOON CST TODAY FOR NDZ006>008-014>016-
024-026>030-038-039-049-052>054.
MN...WIND CHILL ADVISORY UNTIL NOON CST TODAY FOR MNZ001>009-013>017-
022>024-027>032-040.
&&
$$
JR/WJB
AREA FORECAST DISCUSSION
NWS SIOUX FALLS SD
1027 PM CST THU JAN 31 2013
.DISCUSSION.../ISSUED AT 1025 PM CST/
CURRENTLY CLEAR AND COLD OVER MUCH OF THE CWA. HOWEVER A MID LEVEL
CLOUD DECK IS APPROACHING QUICKER THAN EXPECTED FROM THE
WEST...FOCUSED AROUND 700 MB. RAP SEEMS TO HAVE A DECENT HANDLE ON
THIS...AND EXPECT THESE CLOUDS TO CONTINUE TO PROGRESS TO THE EAST.
THEY MAY TEND TO SLOW DOWN AS THEY ENCROACH ON THE ARCTIC AIRMASS
OVERHEAD...BUT THINKING SKIES BECOME OVERCAST AT MITCHELL BY 9Z AND
SIOUX FALLS AND SIOUX CITY BY 12Z. LOW TEMPERATURES TONIGHT ARE
TRICKY. WINDS WILL CONTINUE TO DROP OFF AS HIGH PRESSURE PUSHES
THROUGH. HOWEVER THE LACK OF SNOW COVER OVER THE HEART OF THE CWA
SHOULD LIMIT RADIATIONAL COOLING. THUS DECIDED TO BUMP LOWS UP A
BIT ACROSS THE REGION. ALSO BUMPED THEM SOME ACROSS OUR NORTH WHERE
MODELS HAVE HAD A PRETTY SIGNIFICANT COLD BIAS DURING COLD
OUTBREAKS. SNOW COVER UP THERE IS OLDER AND NOT IDEAL FOR
COOLING...AND PLACES LIKE MARSHALL MAY NEVER SEE THEIR WINDS GO
QUITE LIGHT ENOUGH TO ALLOW FOR GREAT RADIATIONAL COOLING. IT WILL
BE INTERESTING TO SEE WHAT HAPPENS...BUT TEND TO THINK THE HEDGE UP
IN LOWS IS PROBABLY THE WAY TO GO. STILL LOOKS LIKE A LIGHT SNOW
POTENTIAL TOMORROW AFTERNOON AND EVENING. BEST LARGE SCALE FORCING
STAYS TO OUR SOUTH...WITH THE BEST MID LEVEL FRONTAL SIGNATURE TO
OUR NORTH. TEND TO THINK SOMETHING CLOSE TO THE 0Z NAM
VERIFIES...WITH THE BEST BAND OF FLUFFY SNOW AND ACCUMULATIONS OF AN
INCH OR TWO FOLLOWING THE MID LEVEL FRONT...ACROSS THE NORTHEAST
PART OF OUR CWA OR EVEN SLIGHTLY FURTHER NORTHEAST IN SOUTHWEST
MINNESOTA. STILL SHOULD SEE FLURRIES ACROSS THE REST OF THE CWA.
WILL NOT ADJUST POPS AT THIS TIME...BUT INSTEAD ALLOW MIDNIGHT SHIFT
TO REASSESS AND MAKE ANY NECESSARY ADJUSTMENTS. /CHENARD
&&
.AVIATION.../FOR THE 06Z TAF ISSUANCE/
VFR CONDITIONS WILL PREVAIL THROUGH MID-DAY FRIDAY AND WINDS WILL
DECREASE OVERNIGHT AS HIGH PRESSURE SETTLES ACROSS THE REGION. A
FAST MOVING SHORT WAVE WILL BRING A FEW HOUR PERIOD OF LIGHT SNOW
WITH MVFR CIGS FRIDAY...MAINLY MID AFTERNOON FOR THE HON/FSD/SUX TAF
SITES. A PERIOD OF IFR CONDITIONS ARE EXPECTED WITH THE HEAVIEST
PORTION OF THE SNOW BAND HOWEVER...WHICH IS EXPECTED TO SET UP
NORTHEAST OF A LINE APPROXIMATELY FROM KBKX TO KSPW. SOUTHERLY WINDS
FRIDAY WILL SHIFT NORTHWEST BEHIND THIS SHORT WAVE FRIDAY EVENING.
/AEB
&&
.PREVIOUS DISCUSSION.../ISSUED AT 328 PM CST/
THIN LAYER OF ICE CRYSTALS AROUND 2000 FT AGL SHOULD DISSIPATE
FAIRLY QUICKLY THIS EVENING GIVING WAY TO CLEAR SKIES. NORTHWEST
WINDS ARE EXPECTED TO DECREASE AS SURFACE HIGH PRESSURE BUILDS INTO
THE REGION. WINDS SHOULD GRADUALLY DECREASE AND BACK THROUGHOUT THE
NIGHT TAKING ON MORE OF A WEST TO SOUTHWESTERLY DIRECTION FRIDAY
MORNING. WINDS SHOULD REMAIN FAIRLY WEAK...ESPECIALLY ACROSS
SOUTHWEST MINNESOTA INTO NORTHWEST IOWA LEADING TO GREAT RADIATIVE
CONDITIONS. LACK OF SNOW COVER LIMITING POTENTIAL FOR RECORD LOWS
ACROSS THE AREA....BUT HAVE SIDED WITH COOLEST LOWS IN THE NORTH AND
EAST WHERE LINGERING SNOW COVER AND LACK OF WINDS WILL LEAD TO IDEAL
RADIATIVE CONDITIONS.
WARM AIR ADVECTION INCREASES ACROSS CENTRAL SOUTH DAKOTA AFTER 06Z
AND SPREADS EAST THROUGH THE DAY ON FRIDAY. WILL LIKELY SEE CLOUDS
INCREASE IN THE WARM AIR ADVECTION...CREATING THE POTENTIAL FOR
LIGHT SNOW AS THE TEMPERATURE PROFILE DRIFTS THROUGH THE DENDRITIC
LAYER. AREA IS LEFT IN THE RIGHT REAR OF EXITING JET
STREAK...POTENTIALLY GETTING SOME ADDITIONAL HELP IN GENERATING
PRECIPITATION. SNOWFALL AMOUNTS SHOULD BE LIGHT...TOTALING A HALF
AN INCH OR LESS IN MOST LOCATIONS. KEPT TEMPERATURES CLOSER TO
GUIDANCE THAN PREVIOUS FORECAST ESPECIALLY IN THE EAST WHERE HIGHS
WILL LIKELY BE LATE IN THE DAY.
FRIDAY NIGHT TO THURSDAY...QUIET WEATHER EXPECTED THROUGH MOST OF
THE EXTENDED FORECAST.
KEPT LINGERING SNOW IN THE EASTERN HALF OF THE CWA INTO FRIDAY NIGHT
AS SREF/NAM AND TO A LESSER EXTENT THE GFS DROP A SHWV ACROSS THE
AREA WITH SOME LOW QPF ASSOCIATED. AS THIS FEATURE MOVES EAST
DECREASED POPS AND WX INTO THE OVERNIGHT HOURS. TEMPS ON FRIDAY
NIGHT WONT BE NEARLY AS COLD AS THIS PAST WED/THURS WITH LOWS
RANGING FROM THE SINGLE DIGITS NORTHEAST TO AROUND 20 DEGREES
SOUTHWEST.
ON SATURDAY H5 RIDGING MOVES ACROSS THE INTERMOUNTAIN WEST AND
WILL HELP KICK OFF A WARMING TREND OVER THE WEEKEND AND INTO NEXT
WEEK. NORTHWEST FLOW WILL BE THE DOMINANT FEATURE THROUGH THE
EXTENDED. HIGH TEMPS WILL RANGE FROM THE UPPER 20S NORTHEAST TO
LOW 40S SOUTHWEST WITH THE ENTIRE CWA WARMING TO ABOVE FREEZING
FOR HIGHS BY WEDNESDAY. SEVERAL SHWVS EMBEDDED IN THE NW FLOW MOVE
THROUGH THE NORTHERN PLAINS THRU THE PD BUT WITH LIMITED MOISTURE
AND TIMING DIFFERENCES BETWEEN THE GFS AND ECMWF DID NOT MENTION
POPS AFTER FRIDAY NIGHT. /SALLY
&&
.FSD WATCHES/WARNINGS/ADVISORIES...
IA...WIND CHILL ADVISORY UNTIL MIDNIGHT CST TONIGHT FOR IAZ001-012-
020-021-031-032.
WIND CHILL ADVISORY UNTIL 9 AM CST FRIDAY FOR
IAZ002-003-013-014- 022.
MN...WIND CHILL ADVISORY UNTIL 9 AM CST FRIDAY FOR
MNZ071-072-080-081- 089-090-097-098.
NE...WIND CHILL ADVISORY UNTIL MIDNIGHT CST TONIGHT FOR NEZ013-014.
SD...WIND CHILL ADVISORY UNTIL MIDNIGHT CST TONIGHT FOR SDZ057-058-
063>071.
WIND CHILL ADVISORY UNTIL 9 AM CST FRIDAY FOR
SDZ038>040-052>056- 059>062.
&&
$$
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
529 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...TONIGHT AND SUNDAY
529 PM CST SAT FEB 2 2013
THE NEXT SYSTEM IS MOVING TOWARD THE REGION LATE THIS AFTERNOON.
SURFACE LOW PRESSURE WAS OVER NORTHEAST SOUTH DAKOTA WITH A WARM
FRONT EXTENDING SOUTHEAST INTO CENTRAL IOWA. RADAR AND SURFACE
OBSERVATIONS INDICATE LIGHT SNOW IS FALLING ALONG AND NORTH OF THE
WARM FRONT FROM NORTHWEST IOWA INTO CENTRAL MINNESOTA WITH A
SOUTHEAST MOVEMENT. THE 02.18Z NAM HAS REMAINED CONSISTENT SHOWING
THE SURFACE LOW TRACKING ALONG THE WARM FRONT INTO IOWA THIS
EVENING AND THEN INTO SOUTHERN ILLINOIS OVERNIGHT. WEAK
FRONTOGENESIS WILL OCCUR ALONG THE WARM FRONT IN THE 850-700 MB
LAYER AND SHOULD JUST CLIP THE WESTERN SECTIONS OF THE FORECAST
AREA. THIS IS ALSO WHERE THE BEST ISENTROPIC UP GLIDE GOES WITH
1-2 UBAR/S ON THE 275K SURFACE WITH THE STRONGER UP GLIDE
REMAINING FARTHER WEST. THIS WOULD SUGGEST THE MAIN SNOW BAND WILL
MISS BOTH TAF SITES. HOWEVER...THE CONCERN IS THE AREA OF SNOW
JUST COMING INTO THE TWIN CITIES AREA THAT HAS IFR VISIBILITIES IN
IT. BASED ON THE MOVEMENT FROM THE RADAR...IF THIS HOLD
TOGETHER...IT SHOULD IMPACT BOTH TAF SITES LATER THIS EVENING.
WILL HOLD ONTO THE IFR VISIBILITIES PER THE PREVIOUS
FORECAST...BUT CONCERNED THEY MAY NOT LAST AS LONG AS INDICATED.
ANOTHER QUICK SHOT OF DRY AIR MOVES IN SUNDAY MORNING ALLOWING THE
MVFR CEILINGS TO SCATTER OUT BEFORE THE NEXT SYSTEM STARTS TO
APPROACH RETURNING VFR CEILINGS TO BOTH SITES BY MID AFTERNOON.
THIS NEXT SYSTEM WILL BRING YET MORE SNOW AND THIS WILL HAVE TO BE
ADDED WITH THE NEXT SET OF FORECASTS.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
230 PM CST SAT FEB 2 2013
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
SHORT TERM...RIECK
LONG TERM....RIECK
AVIATION...04
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
346 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...
1200 AM CST FRI FEB 1 2013
CLOUDS WILL BE ON THE INCREASE LATE THIS AFTERNOON...QUICKLY
LOWERING/THICKENING BY 00Z AS AN UPPER LEVEL SHORTWAVE APPROACHES.
ENOUGH THERMODYNAMIC/UPPER LEVEL FORCING FOR -SN PRODUCTION. ONSET
SHOULD BE AROUND THE 00Z TIME FRAME...AND VSBYS SHOULD QUICKLY DROP
TO AROUND 1-2SM AFTER IT STARTS. WILL KEEP TAFS AT 2SM FOR NOW. DEEP
DENDRITIC SNOW GROWTH REGION...AND EXPECT LARGER FLAKES...DRY SNOW
THAT COULD ADD UP QUICKLY. THE SYSTEM MOVES THROUGH AT A GOOD CLIP
THOUGH...SO 1-2 INCHES IS EXPECTED. MOST ACCUMULATIONS SHOULD BE
OVER BY 06Z.
THE REGION WILL BE UNDER AN ACTIVE NORTHWEST FLOW...WHICH WILL PUSH
SHORTWAVE AFTER SHORTWAVE ACROSS THE UPPER MISSISSIPPI RIVER VALLEY.
THE TAF SITES WILL BE IMPACTED BY SIMILAR SYSTEMS SAT AND SUN
NIGHTS.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
344 PM CST FRI FEB 1 2013
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
SHORT TERM...BOYNE
LONG TERM...BOYNE
AVIATION.....RIECK
AREA FORECAST DISCUSSION
NWS CHEYENNE WY
1128 AM MST FRI FEB 1 2013
.UPDATE...THE UPPER LEVEL DISTURBANCE IS MOVING SOUTHEAST ACROSS
WYOMING THIS MORNING...AND SCATTERED SNOW SHOWERS ARE DEVELOPING
IN NORTHERN WYOMING WITH THE WAVE. THESE SHOWERS WILL MOVE
SOUTHEAST INTO THE FORECAST AREA THROUGH THIS AFTERNOON. INCREASED
POPS TO A MORE SCATTERED COVERAGE ACROSS THE EASTERN PLAINS BASED
ON CURRENT TRENDS AND AS MOST 12Z MODELS DEPICT THIS SITUATION.
FOLLOWED THE RUC TREND FOR TIMING...WITH SHOWERS MOVING INTO THE
NORTHERN ZONES OVER THE NEXT HOUR OR TWO...THEN MOVING INTO THE
SOUTHERN ZONES LATER THIS AFTERNOON. DID NOT MAKE ANY SIGNIFICANT
CHANGES TO SNOW CHANCES ACROSS THE HIGH COUNTRY. SOME PARTIAL
CLEARING AHEAD OF THE WAVE HAS ALLOWED TEMPERATURES TO INCREASE
MORE THAN ORIGINALLY FORECAST...SO BUMPED UP TEMPS
ACCORDINGLY...ESPECIALLY ACROSS THE EASTERN PLAINS. COULD SEE A
FEW OF THE SHOWERS START AS LIGHT RAIN AS A RESULT OF THE WARMER
TEMPS...BUT EXPECT THESE TO QUICKLY CHANGE OVER TO SNOW. RJM
.AVIATION..18Z TAF ISSUANCE...
CLOUD BASES WILL LOWER OVER THE CWA INTO MID AFTERNOON AS SNOW
SHOWERS BECOME FAIRLY WIDESPREAD OVER THE CWA. CEILINGS AND
VISIBILITIES IN SNOW WILL FREQUENTLY BE MVFR BETWEEN 20Z AND
01Z SATURDAY. THERE WILL ALSO BE PERIODS OF IFR VISIBILITIES
ASSOCIATED WITH THE HEAVIER SNOW SHOWERS. THE SNOW SHOWERS WILL
BE ACCOMPANIED BY A PERIOD OF CLEAR OR RIME ICING UP THROUGH 15000
FEET MSL. THE MOUNTAINS WILL BE OBSCURED THROUGH THIS EVENING.
AFTER THAT TIME...VFR CONDITIONS WILL RETURN TO THE CWA AND PERSIST
THROUGH EARLY NEXT WEEK.
WEST TO NORTHWEST SURFACE WINDS WILL GUST AS HIGH AS 45 KNOTS
THROUGH 01Z SATURDAY...MAINLY OVER SOUTHEAST WYOMING. WIND
GUSTS WILL REMAIN AS HIGH AS 35 KNOTS TONIGHT AND SATURDAY IN
AREAS ALONG AND WEST OF THE LARAMIE RANGE. A WEAK TO MODERATE
MOUNTAIN WAVE WILL EXIST INTO THE EARLY EVENING TO THE LEE OF
THE SNOWY RANGE AS WELL AS LARAMIE PEAK.
WEILAND
&&
.PREV DISCUSSION... /ISSUED 419 AM MST FRI FEB 1 2013/
SHORT TERM...TODAY THROUGH SUNDAY NIGHT...
SHORTWAVE OVER FAR WESTERN MONTANA WILL QUICKLY MAKE ITS WAY
ACROSS SOUTHEAST WYOMING BY THIS AFTERNOON. SNOW WILL MAINLY BE
FOUND AT HIGHER ELEVATIONS AHEAD OF THIS FAST MOVING DISTURBANCE.
UPPER LEVEL JET AND SHORTWAVE WILL LEND PLENTY OF UPPER LEVEL
DYNAMICS TODAY. MAIN LIMITING FACTOR WILL BE RELATIVELY DRY
NORTHWEST FLOW ALOFT AND DOWN SLOPE EAST OF THE LARAMIE RANGE.
ALONG AND WEST OF THE LARAMIE RANGE THERE WILL BE ENOUGH MOISTURE
UNDER UP SLOPE FLOW FOR MORE WIDESPREAD SNOW...ESPECIALLY IN THE
MOUNTAINS. WINTER WEATHER ADVISORY IS IN EFFECT THROUGH 9 PM THIS
EVENING FOR THE SNOWY AND SIERRA RANGES WHERE 6 TO 9 INCHES OF
SNOW IS GENERALLY EXPECTED. GIVEN A 1 TO 4 INCHES HAVE ALREADY
FALLEN SINCE LAST EVENING...SHOULD EASILY HIT ADVISORY CRITERIA.
MAY EVEN SEE A FEW LOCATIONS APPROACH ONE FOOT OF SNOW BEFORE
TAPERING OFF THIS EVENING. ALSO IT WILL BE WINDY WITH
SIGNIFICANTLY REDUCED VISIBILITIES IN THE MOUNTAINS DUE TO BLOWING
SNOW.
INTO THE PLAINS ISOLATED TO SCATTERED SNOW SHOWERS CAN BE EXPECTED
THIS AFTERNOON. THE COMBINATION OF UPPER LEVEL LIFT AND LOW LEVEL
INSTABILITY SHOULD BE ENOUGH TO FIRE SOME SNOW SHOWERS OFF THE
NORTHERN LARAMIE RANGE BY EARLY THIS AFTERNOON. SHOWER ACTIVITY
WILL PROPAGATE SOUTHEAST UNDER NORTHWEST FLOW ALOFT. LIFTED INDEX
1 TO -1 THIS AFTER OVER SOUTHEAST WYOMING AND EXTENDING INTO THE
WESTERN NEBRASKA PANHANDLE. COULD SEE A FEW SNOW SHOWERS ON THE
HEAVIER SIDE PRODUCING QUICK SHOTS OF ACCUMULATING SNOW. ALTHOUGH
MOST OF THE AREA WILL SEE LITTLE TO NO ACCUMULATION...ISOLATED
SPOTS COULD EASILY PICK UP AN INCH OF SNOW. SNOW SHOWERS WILL
QUICKLY DIE OFF THIS EVENING WITH THE LOST OF SURFACE HEATING AND
UPPER LEVEL DYNAMICS WITH THE SHORTWAVE MOVING INTO NEBRASKA AND
KANSAS.
OTHER CONCERN TODAY IS THE WINDS. CANCELLED THE HIGH WIND WARNING
WHICH WAS IN EFFECT THROUGH 11 AM THIS MORNING. WINDS NEVER
MATERIALIZED TO THE EXTENT THAT WAS PREVIOUSLY EXPECTED. CURRENTLY
WINDS 25 TO 35 MPH WITH A FEW RANDOM GUSTS AROUND 50 MPH IN THE
ARLINGTON AREA. STRONGEST WINDS SEEM TO BE STAYING ABOVE THE
INVERSION...AT LEAST THAT IS WHAT MODEL WIND AND STABILITY CROSS
SECTIONS SUGGEST. SHOULD BE ABLE TO MIX DOWN SOME OF THOSE WINDS
LATER TODAY...BUT BASED ON MODEL FORECASTS WINDS SHOULD STAY BELOW
WIND WARNING CRITERIA TODAY. STILL A FEW GUSTS TO 60 MPH AREA NOT
COMPLETELY OUT OF THE QUESTION WITH THE PASSAGE OF THE SHORTWAVE.
ONCE THE SHORTWAVE PASSES...SNOW WILL END AND SKIES WILL BEGIN TO
CLEAR. THIS SHOULD BE THE BEGINNING OF AN EXTENDED DRY PERIOD
ACROSS THE FORECAST AREA. NO MENTION FOR PRECIPITATION THROUGH
SUNDAY NIGHT AS DRY NORTHWEST FLOW AND BUILDING UPPER LEVEL RIDGE
KEEP POP CHANCES VERY VERY LOW.
LONG TERM...MONDAY THROUGH THURSDAY...
MILD AND MAINLY DRY WEATHER EXPECTED OVER THE CWA DURING THIS
PERIOD WITH NO SIGNIFICANT SYSTEMS SEEN AFFECTING THE AREA. MODELS
DEPICT ONE SHORTWAVE PASSING BY LATE ON WEDNESDAY BRINGING SOME
MINOR COOLING BEHIND IT FOR THURSDAY. GFS DRY WITH THIS SYSTEM WHILE
ECMWF PAINTS SOME LOW QPF IN ASSOCIATION WITH IT. LATEST ECMWF
RUN HAS DECREASED QPF AND WILL SEE IF IT EVENTUALLY COMES IN LINE
WITH THE GFS SOLUTION. FOR NOW WILL KEEP SOME VERY LOW "SILENT"
POPS FOR THIS SYSTEM. OTHERWISE NW FLOW EARLY NEXT WEEK WILL BACK
TO WESTERLY AS UPPER RIDGE AXIS PASSES ACROSS LATE TUESDAY. UPPER
RIDGE THEN REBUILDS OVER THE REGION THURSDAY IN WAKE OF PREVIOUSLY
MENTIONED SHORTWAVE.
FIRE WEATHER...
UPPER LEVEL DISTURBANCE TO BRING SNOW TO THE MOUNTAINS OF SOUTHEAST
WYOMING TODAY. ISOLATED TO SCATTERED SNOW SHOWERS OVER THE REST
OF SOUTHEAST WYOMING...AND INTO THE NEBRASKA PANHANDLE THIS
AFTERNOON. CLEARING SKIES TONIGHT BEHIND THE DISTURBANCE THEN
WARMER AND DRY THROUGH NEXT WEEK.
&&
.CYS WATCHES/WARNINGS/ADVISORIES...
WY...WINTER WEATHER ADVISORY UNTIL 9 PM FRIDAY FOR WYZ112-WYZ114.
NE...NONE.
&&
$$
SHORT TERM/FIRE WEATHER...LIEBL
LONG TERM...RE
AREA FORECAST DISCUSSION
NWS LINCOLN IL
1125 PM CST SAT FEB 2 2013
.DISCUSSION...
ISSUED 824 PM CST SAT FEB 2 2013
AREA OF LIGHT SNOW DROPPING SOUTHEAST ACROSS IOWA/NORTHERN
MISSOURI HAS BEEN HANDLED FAIRLY WELL ON THE RECENT HRRR AND RAP
RUNS. HEAVIER SNOW AXIS HAS BEEN TRENDING TOWARD AREAS ALONG/WEST
OF THE MISSISSIPPI RIVER...BUT THE SNOW AREA WILL BEGIN MOVING
INTO THE WESTERN CWA IN THE NEXT HOUR OR TWO. MOST OF THE HEAVIER
PRECIP HAS BEEN ASSOCIATED WITH A VORT MAX DROPPING SOUTHEAST
THROUGH THE MID-MISSISSIPPI VALLEY...BUT SOME LIGHT SNOW IS ALSO
OCCURRING FURTHER NORTH CLOSER TO THE CENTER OF THE INCOMING
CLIPPER SYSTEM. GREATEST PRECIP THREAT ACROSS THE WESTERN CWA WILL
BE THROUGH ABOUT 2 AM...WITH THE EASTERN CWA MAINLY AFTER
MIDNIGHT.
ZONES/GRIDS WERE UPDATED EARLIER TO REFLECT THESE PRECIPITATION
TRENDS...AS WELL AS ADJUST THE TEMPERATURE TRENDS.
GEELHART
&&
.AVIATION...
ISSUED 1125 PM CST SAT FEB 2 2013
LARGEST AREA OF SNOW HAS BEEN TRAVELING SOUTHEAST ALONG THE
MISSISSIPPI RIVER. HAVE HAD SOME LIGHT SNOW AT TIMES OVER THE LAST
COUPLE HOURS AT KPIA/KSPI WITH VISIBILITIES BRIEFLY DOWN TO 2-3
MILES. RADAR AND MODEL DATA SHOWING SOME ADDITIONAL LIGHT SNOW IN
SOUTHEAST IOWA WHICH WILL MOVE THROUGH THE CENTRAL ILLINOIS TAF
SITES THROUGH ABOUT 09Z. CEILINGS AS OF LATE HAVE MAINLY BEEN
VFR...BUT SHOULD SOON FALL TO MVFR LEVELS FOR SEVERAL HOURS AS THE
PARENT CLIPPER SYSTEM PASSES THROUGH THE STATE. CLEARING IS
EXPECTED FROM WEST TO EAST DURING THE MID TO LATE MORNING. THE
NEXT CLIPPER SYSTEM SHOULD BRING AN INCREASE OF MID AND HIGH
CLOUDS SUNDAY EVENING...BUT ANY ASSOCIATED SNOW IS CURRENTLY
EXPECTED TO REMAIN IN NORTHERN ILLINIOS.
GEELHART
&&
.PREV DISCUSSION...
ISSUED 300 PM CST SAT FEB 2 2013
A COMBINATION OF SURFACE TROUGHS AND UPPER LEVEL SHORTWAVES WILL
KEEP LIGHT SNOW IN THE SHORT TERM FORECAST. THEIR TRACKS WILL ALSO
BE FAVORABLE FOR KEEPING COLDER AIR IN PLACE ACROSS CENTRAL IL. WE
WILL WARM TO AROUND NORMAL FOR THE EARLY PART OF NEXT WEEK...BUT
ABOVE NORMAL TEMPS WILL BE DELAYED UNTIL THURSDAY AND SATURDAY. A
WEAK COLD FRONTAL PASSAGE LATER THURSDAY WILL COOL DOWN TEMPS
SLIGHTLY FOR FRIDAY.
SHORT TERM...TONIGHT THROUGH MONDAY NIGHT.
THE WATER VAPOR SATELLITE SHOWS A MYRIAD OF SHORTWAVES UPSTREAM
EXTENDING FROM NW IL TO THE NORTHERN PLAINS AND INTO SOUTHWEST
CANADA. THE DEEP UPPER TROUGH DOMINATING THE EASTERN 2/3RDS OF THE
COUNTRY WILL KEEP THAT NORTHWEST FLOW IN PLACE...SENDING THOSE
SHORTWAVES DIRECTLY AT AMERICA/S HEARTLAND INTO EARLY NEXT WEEK.
WE HAVE A TRAILING SECONDARY WAVE TRIGGERING LIGHT SNOW ACROSS
OUR NW COUNTIES THIS AFTERNOON. THAT AREA OF SNOW WILL PROGRESS
SOUTHEASTWARD THIS EVENING...WITH A BREAK IN THE SNOWFALL EXPECTED
FOR A FEW HOURS. THEN A MORE POTENT SHORTWAVE WILL MOVE SOUTHEAST
FROM EASTERN SOUTH DAKOTA AND PASS ALONG THE ILLINOIS-MISSOURI
BORDER LATER TONIGHT. ASSUMING THAT TRACK TONIGHT...THE BAND OF
HEAVIER SNOW /ONE INCH/ WILL BE CENTERED BETWEEN SPRINGFIELD AND
ST LOUIS...WITH UP TO AN INCH REACHING NEAR JACKSONVILLE. SNOW
TOTALS OF ONE HALF INCH COULD EXTEND AS FAR AS PEORIA TO LINCOLN
TO MATTOON AND LAWRENCEVILLE. NORTHEAST OF THAT LINE...MAINLY A DUSTING
IS EXPECTED. THE GFS/NAM/CANADIAN GEM/HRRR/RAP ALL POINT TOWARD
THAT GENERAL SCENARIO.
THE SNOW SHOULD COME TO AN END BY SUNDAY MORNING EVERYWHERE BUT
POSSIBLY ALONG THE INDIANA BORDER FROM DANVILLE TO LAWRENCEVILLE.
OTHERWISE SUNDAY WILL SEE DECREASING CLOUDS BUT BLUSTERY NORTHWEST
WINDS AND CHILLY CONDITIONS WITH HIGHS IN THE MID TO UPPER 20S.
MONDAY WILL SEE A LOW PRESSURE SYSTEM AND UPPER SHORTWAVE PASS
ACROSS ILLINOIS. IT APPEARS THAT THE BEST FORCING FOR LIGHT SNOW
WILL RESIDE ACROSS FAR NORTHERN ILLINOIS AND SOUTHERN
WISCONSIN...WHERE ISENTROPIC LIFT WILL COINCIDE BEST WITH MOISTURE
AND LOW CONDENSATION PRESSURE DEFICITS. THE SURFACE LOW WILL PASS
ACROSS CENTRAL IL BETWEEN 18Z MON AND 00Z TUE...WITH AN
INTENSIFICATION OF PRECIP JUST AHEAD OF THE LOW IN OUR EAST AND
SOUTHEASTERN COUNTIES MON AFTERNOON. WE COULD SEE 0.5 TO 1 INCH OF
SNOW SOUTHEAST OF A LINE FROM CHAMPAIGN TO EFFINGHAM...WITH LITTLE
TO NO PRECIP WEST OF A LINE FROM BMI TO TAYLORVILLE. THE SNOW
COULD LINGER INTO MONDAY EVENING NEAR LWV.
LONG TERM...TUESDAY THROUGH SATURDAY.
A BRIEF APPEARANCE OF HIGH PRESSURE TUESDAY MORNING WILL BE PUSHED
ASIDE BY THE NEXT SHORTWAVE MOVING FROM MINNESOTA ACROSS
WISCONSIN...AND A COLD FRONT EXTENDING SOUTH ACROSS IOWA. THE
ASSOCIATED SURFACE LOW WILL TRACK ACROSS WISC AS WELL...ALONG WITH
THE BEST FORCING FOR PRECIP. WE DO NOT EXPECT MUCH IN THE WAY OF
SNOW IN OUR COUNTIES...ALTHOUGH SOME FLURRIES MAY DEVELOP NORTH OF
A LINE FROM PEORIA TO CHAMPAIGN. THE TRACK OF THIS SYSTEM HAS
CHANGED FROM YESTERDAYS MODELS...PUSHING IT FARTHER NORTH NOW.
WEDNESDAY LOOKS TO BE DRY AND SLIGHTLY WARMER WITH HIGHS IN THE
MID TO UPPER 30S. THE NEXT COLD FRONT LOOKS TO ARRIVE ON
THURSDAY...WITH RAIN OR SNOW POSSIBLE THURSDAY MORNING BUT MAINLY
RAIN THURSDAY AFTERNOON. COLD AIR FILTERING IN BEHIND THAT FRONT
MAY CHANGE ANY LINGERING PRECIP IN THE EVENING BACK OVER TO
LIGHT SNOW BY LATE EVENING...AS TEMPS DIP BACK BELOW FREEZING.
FRIDAY LOOKS TO BE A LITTLE COOLER THAN THURSDAYS HIGHS AHEAD OF
THE FRONT...BUT STILL INTO THE UPPER 30S OR LOW 40S. SATURDAY WILL
SEE INCREASING CLOUDS AHEAD OF A MORE PROMINENT LOW PRESSURE
SYSTEM ARRIVING ON SUNDAY. SOME LIGHT RAIN WILL BE POSSIBLE IN OUR
WESTERN COUNTIES BY SATURDAY AFTERNOON...BUT THE TRENDS THE LAST
COUPLE OF DAYS HAVE BEEN TO SLOW DOWN THE ARRIVAL OF RAIN ON
SATURDAY. WE MAY HAVE A BETTER CHANCE OF A DRY DAY ON SATURDAY AS
ADDITIONAL MODEL RUNS COME IN OVER THE NEXT FEW DAYS. HIGHS ON
SATURDAY SHOULD HAVE ENOUGH SUPPORT FOR SUNSHINE AND SOUTHERLY
WINDS TO REACH THE MID TO UPPER 40S.
SHIMON
&&
.ILX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS JACKSON KY
311 AM EST SUN FEB 3 2013
.UPDATE...
ISSUED AT 140 AM EST SUN FEB 3 2013
UPDATED THE FORECAST EARLIER THIS HOUR TO REFLECT THE BUILDING
INTENSITY OF THE SNOW SHOWERS IN THE FAR EAST AS THIS FIRST WAVE
EXITS THE AREA. RAISED QPF AND SNOW AMOUNTS FOR THIS WITH AROUND AN
INCH OF NEW SNOW EXPECTED. ALSO FINE TUNED THE FORECAST INTO THE DAY
SUNDAY FOR THE NEXT WAVE COMING IN FROM THE STL AREA AROUND DAWN...
BASED ON THE LATEST RUC AND HRRR SCENARIOS. THIS ONE SHOULD TARGET
THE SOUTHERN PARTS OF THE CWA...BUT WILL ALSO PROBABLY IMPACT THE
REST OF THE AREA WITH ANOTHER ROUND OF SNOW. ANTICIPATE UP TO AN
ADDITIONAL 1/2 INCH OF SNOW OUTSIDE OF THE CUMBERLAND VALLEY AND THE
HIGHER TERRAIN IN THE EAST THROUGH MIDDAY SUNDAY...WHERE ANOTHER INCH
OR SO IS POSSIBLE. WILL KEEP WATCHING IT TRACK THIS WAY IF IT
CONTINUES TO PRODUCE HEALTHY ACCUMULATIONS WILL CONSIDER /RE/HOISTING
A SHORT DURATION ADVISORY ACROSS THE SOUTH. TEMPERATURES WILL ALSO BE
A FACTOR DOWN THERE...THOUGH. UPDATES HAVE BEEN SENT TO THE NDFD AND
WEB SERVERS ALONG WITH AN SPS FOR THE FAR EAST AND A NEW ZFP/HWO.
UPDATE ISSUED AT 1142 PM EST SAT FEB 2 2013
LIGHT PRECIPITATION HAS LINGERED A BIT LONGER IN THE WAKE OF THE
EXITING CLIPPER. TEMPERATURES HAVE ALSO CREPT UP A BIT IN
PLACES...ALLOWING FOR MORE OF MIX OF FLURRIES...DRIZZLE...LIGHT
RAIN AND SNOW. HAVE TRIED TO ACCOUNT FOR THESE CURRENT CONDITIONS A
BIT BETTER IN THE FORECAST. HAVE ALSO GONE LIKELY POPS FOR THE NEXT
CLIPPER TO AFFECT MAINLY THE SOUTHWESTERN COUNTIES TOWARDS DAWN INTO
THE MID-MORNING HOURS. HAVE KEPT THIS AS ALL SNOW FOR NOW...HOWEVER
IF THE SOUTHWEST WINDS HOLD UP ENOUGH THROUGH THE NIGHT...THEN THERE
MAY BE SOME RAIN TO CONTEND WITH AT THE ONSET OF PRECIPITATION.
UPDATE ISSUED AT 914 PM EST SAT FEB 2 2013
LAST BAND OF DECENT SNOW IS WORKING EAST OUT OF THE AREA. SOME OF THE
MORE ENHANCED BANDS...GENERALLY ALIGNED FROM PIKEVILLE TO JACKSON
COULD PUT DOWN A QUICK DUSTING TO QUARTER OF AN INCH. THIS BAND WILL
BE EXITING IN THE NEXT HOUR...AND WITH LITTLE OR SNOW ACCUMULATION
EXPECTED FOR THE REST OF THE EVENING...WENT AHEAD AND DROPPED
ADVISORY HEADLINES. DID ISSUE A SPECIAL WEATHER STATEMENT
HIGHLIGHTING THE REFREEZE POTENTIAL OF MELTED SNOWFALL AS AFTERNOON
TEMPERATURES IN MANY VALLEY REACHED OR EXCEEDED THE FREEZING MARK AND
OVERNIGHT LOWS LOOK TO RANGE FROM THE LOWER TO MIDDLE 20S NORTH...AND
THE MIDDLE TO UPPER 20S SOUTH. ANOTHER CLIPPER WILL MOVE TOWARDS IN
FROM THE NORTHWEST TOWARDS DAWN...WITH ANOTHER SHOT OF LIGHT SNOW.
THIS BAND LOOKS TO TARGET THE SOUTHWESTERN COUNTIES BETWEEN 09 AND
12Z...AND THEN IT WILL SHIFT TO THE NORTHEAST THROUGH THE REST OF THE
AREA IN TANDEM WITH A SUPPORTIVE UPPER LEVEL JET STREAK. EXPECT UP TO
A HALF INCH OF SNOW IN THE SOUTHWEST...AND AROUND A QUARTER INCH TO
THE NORTHEAST.
&&
.SHORT TERM...(THIS EVENING THROUGH SUNDAY NIGHT)
ISSUED AT 354 PM EST SAT FEB 2 2013
AFTER A RELATIVE LULL IN SNOW EARLY AFTERNOON...IT HAS STARTED TO
INCREASE AGAIN AS MODELS DEPICTED. HOWEVER...WITH TEMPS WELL ABOVE
FREEZING IN OUR FAR SW COUNTIES...SUSPECT THAT WHAT FALLS THERE WILL
INDEED BE MIXED WITH OR IN THE FORM OF RAIN LATE TODAY. THIS ROUND OF
PRECIP EXITS TO THE EAST THIS EVENING...WITH LITTLE ADDITIONAL PRECIP
EXPECTED OVERNIGHT. ANOTHER ROUND OF LIGHT SNOW IS EXPECTED TO MOVE
THROUGH FROM WEST TO EAST...ESPECIALLY IN OUR SOUTHERN COUNTIES....ON
SUNDAY MORNING. HOWEVER...PRECIP SHOULD BE LIGHT...WITH SOME QUESTION
AS TO HOW MANY PLACES WILL ACTUALLY MEASURE. IN LIGHT OF THIS...WILL
UPDATE THE WINTER WX ADVISORY TO ALLOW A STEPPED EXPIRATION FROM WEST
TO EAST THIS EVENING. HOPEFULLY...WHATEVER OCCURS ON SUNDAY MORNING
CAN BE HANDLED WITH AN SPS IF NECESSARY. THE SNOW ON SUNDAY SHOULD
THEN EXIT TO THE EAST...LEAVING JUST FLURRIES AROUND INTO SUNDAY
NIGHT. LAPSE RATES IN THE LOWEST LEVELS WILL BE STEEP THROUGH MOST OF
THE PERIOD. HOWEVER...THOSE STEEP LAPSE RATES WILL NOT EXTEND MUCH
PAST THE -10C LEVEL...AND LOW LEVEL FLOW WILL BE LARGELY
SOUTHWESTERLY OR WESTERLY WITH ONLY A PARTIAL UPSLOPE COMPONENT.
THESE FACTORS WILL LIKELY LIMIT UPSLOPE/ELEVATION ENHANCEMENT IN OUR
SOUTHEAST COUNTIES. ALTHOUGH...SOME ELEVATION DEPENDENCE MAY OCCUR
THROUGH THIS EVENING DUE TO SOME LOWER ELEVATIONS IN THE SOUTH BEING
ABOVE FREEZING.
.LONG TERM...(MONDAY NIGHT THROUGH SATURDAY)
ISSUED AT 311 AM EST SUN FEB 3 2013
THE EASTERN U.S. TROUGH WILL BE RELAXING AT THE START OF THE
PERIOD...HOWEVER WE REMAIN IN NORTHWEST FLOW ALOFT THROUGH MIDWEEK.
A RIPPLE IN THIS NORTHWEST FLOW WILL BRING ANOTHER ROUND OF LIGHT
PRECIP TO OUR REGION MONDAY NIGHT INTO TUESDAY MORNING. THE SURFACE
LOW APPEARS TO TRACK JUST TO OUR NORTH...WITH A STOUT SOUTHWESTERLY
LOW LEVEL JET IN PLACE OVER THE COMMONWEALTH. THUS...EXPECT ENOUGH
WARM AIR TO PUNCH NORTH THAT PRECIP SHOULD BE PREDOMINANTLY RAIN
MONDAY EVENING. MY ONLY CONCERN IS THAT A FEW VALLEYS MAY DROP DOWN
TO FREEZING BEFORE THE PRECIP MOVES IN CAUSING SOME PATCHY FREEZING
RAIN...HOWEVER THAT IS LOW PROBABILITY AT THIS POINT. SOME SNOW MAY
MIX IN WITH THE RAIN OVER OUR NORTHERN COUNTIES AS COLDER AIR
FILTERS IN BEHIND THE FRONT AFTER MIDNIGHT...BUT MODEL SOUNDINGS
SHOW WE LOSE FAVORABLE SNOW GROWTH TEMPS IN THE CLOUD LAYER AT THE
SAME TIME SO WE MAY JUST GO OVER TO SOME DRIZZLE/FREEZING DRIZZLE.
THIS WOULD ALL TAPER OFF TUESDAY MORNING AS THE SYSTEM EXITS TO OUR
EAST.
A QUIET PERIOD APPEARS IN STORE FROM TUESDAY NIGHT THROUGH THURSDAY
AS HEIGHTS RISE ALOFT SENDING THE NEXT RIPPLE IN THE FLOW JUST TO
OUR NORTH. WE WILL MODERATE AS WELL...WITH TEMPS RETURNING TO NEAR
50 BY THURSDAY.
A SHORTWAVE TROUGH WILL THEN PASS THROUGH THE GREAT LAKES AND OHIO
VALLEY THURSDAY NIGHT AND FRIDAY SENDING A COLD FRONT THROUGH OUR
REGION. TEMPS SHOULD BE WARM ENOUGH FOR ALL RAIN WITH THIS. AFTER A
SLIGHT COOL DOWN ON FRIDAY...WE WILL WARM BACK INTO THE 50S ON
SATURDAY AS RIDGING BUILDS OVER OUR REGION IN RESPONSE TO A
DEEPENING TROUGH OVER THE INTERMOUNTAIN WEST. THIS SYSTEM WILL BRING
UNSETTLED WEATHER BACK TO OUR REGION LATE IN THE WEEKEND AND INTO
EARLY NEXT WEEK.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SUNDAY NIGHT)
ISSUED AT 150 AM EST SUN FEB 3 2013
THE CIGS AND VSBY SHOULD STAY UP AT THE TAF SITES THROUGH THE NEXT
SEVERAL HOURS. THE NEXT MID LEVEL WAVE WILL MOVE INTO THE AREA
TOWARDS DAWN WITH RENEWED SNOW SHOWERS EXPECTED. WITH THIS...EXPECT
CIGS TO LOWER INTO IFR OR WORSE CONDITIONS WITH VIS FOLLOWING SUIT AS
THE SNOW MOVES IN. AFTER THE SNOW TAPERS OFF BY MID-MORNING...EXPECT
MVFR CIGS AT AROUND 1500 FT TO HANG ON THROUGH THE END OF THE PERIOD.
WINDS WILL BE FROM THE WEST AT 5 TO 10 KTS THROUGH TONIGHT...THOUGH
OCCASIONAL GUSTS TO 15 KTS WILL BE POSSIBLE...ASSOCIATED WITH ANY
HEAVIER SNOW BAND...EARLY TODAY.
&&
.JKL WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...GREIF
SHORT TERM...HAL
LONG TERM....ABE
AVIATION...GREIF
AREA FORECAST DISCUSSION...UPDATED
NWS JACKSON KY
150 AM EST SUN FEB 3 2013
.UPDATE...
ISSUED AT 140 AM EST SUN FEB 3 2013
UPDATED THE FORECAST EARLIER THIS HOUR TO REFLECT THE BUILDING
INTENSITY OF THE SNOW SHOWERS IN THE FAR EAST AS THIS FIRST WAVE
EXITS THE AREA. RAISED QPF AND SNOW AMOUNTS FOR THIS WITH AROUND AN
INCH OF NEW SNOW EXPECTED. ALSO FINE TUNED THE FORECAST INTO THE DAY
SUNDAY FOR THE NEXT WAVE COMING IN FROM THE STL AREA AROUND DAWN...
BASED ON THE LATEST RUC AND HRRR SCENARIOS. THIS ONE SHOULD TARGET
THE SOUTHERN PARTS OF THE CWA...BUT WILL ALSO PROBABLY IMPACT THE
REST OF THE AREA WITH ANOTHER ROUND OF SNOW. ANTICIPATE UP TO AN
ADDITIONAL 1/2 INCH OF SNOW OUTSIDE OF THE CUMBERLAND VALLEY AND THE
HIGHER TERRAIN IN THE EAST THROUGH MIDDAY SUNDAY...WHERE ANOTHER INCH
OR SO IS POSSIBLE. WILL KEEP WATCHING IT TRACK THIS WAY IF IT
CONTINUES TO PRODUCE HEALTHY ACCUMULATIONS WILL CONSIDER /RE/HOISTING
A SHORT DURATION ADVISORY ACROSS THE SOUTH. TEMPERATURES WILL ALSO BE
A FACTOR DOWN THERE...THOUGH. UPDATES HAVE BEEN SENT TO THE NDFD AND
WEB SERVERS ALONG WITH AN SPS FOR THE FAR EAST AND A NEW ZFP/HWO.
UPDATE ISSUED AT 1142 PM EST SAT FEB 2 2013
LIGHT PRECIPITATION HAS LINGERED A BIT LONGER IN THE WAKE OF THE
EXITING CLIPPER. TEMPERATURES HAVE ALSO CREPT UP A BIT IN
PLACES...ALLOWING FOR MORE OF MIX OF FLURRIES...DRIZZLE...LIGHT
RAIN AND SNOW. HAVE TRIED TO ACCOUNT FOR THESE CURRENT CONDITIONS A
BIT BETTER IN THE FORECAST. HAVE ALSO GONE LIKELY POPS FOR THE NEXT
CLIPPER TO AFFECT MAINLY THE SOUTHWESTERN COUNTIES TOWARDS DAWN INTO
THE MID-MORNING HOURS. HAVE KEPT THIS AS ALL SNOW FOR NOW...HOWEVER
IF THE SOUTHWEST WINDS HOLD UP ENOUGH THROUGH THE NIGHT...THEN THERE
MAY BE SOME RAIN TO CONTEND WITH AT THE ONSET OF PRECIPITATION.
UPDATE ISSUED AT 914 PM EST SAT FEB 2 2013
LAST BAND OF DECENT SNOW IS WORKING EAST OUT OF THE AREA. SOME OF THE
MORE ENHANCED BANDS...GENERALLY ALIGNED FROM PIKEVILLE TO JACKSON
COULD PUT DOWN A QUICK DUSTING TO QUARTER OF AN INCH. THIS BAND WILL
BE EXITING IN THE NEXT HOUR...AND WITH LITTLE OR SNOW ACCUMULATION
EXPECTED FOR THE REST OF THE EVENING...WENT AHEAD AND DROPPED
ADVISORY HEADLINES. DID ISSUE A SPECIAL WEATHER STATEMENT
HIGHLIGHTING THE REFREEZE POTENTIAL OF MELTED SNOWFALL AS AFTERNOON
TEMPERATURES IN MANY VALLEY REACHED OR EXCEEDED THE FREEZING MARK AND
OVERNIGHT LOWS LOOK TO RANGE FROM THE LOWER TO MIDDLE 20S NORTH...AND
THE MIDDLE TO UPPER 20S SOUTH. ANOTHER CLIPPER WILL MOVE TOWARDS IN
FROM THE NORTHWEST TOWARDS DAWN...WITH ANOTHER SHOT OF LIGHT SNOW.
THIS BAND LOOKS TO TARGET THE SOUTHWESTERN COUNTIES BETWEEN 09 AND
12Z...AND THEN IT WILL SHIFT TO THE NORTHEAST THROUGH THE REST OF THE
AREA IN TANDEM WITH A SUPPORTIVE UPPER LEVEL JET STREAK. EXPECT UP TO
A HALF INCH OF SNOW IN THE SOUTHWEST...AND AROUND A QUARTER INCH TO
THE NORTHEAST.
&&
.SHORT TERM...(THIS EVENING THROUGH SUNDAY NIGHT)
ISSUED AT 354 PM EST SAT FEB 2 2013
AFTER A RELATIVE LULL IN SNOW EARLY AFTERNOON...IT HAS STARTED TO
INCREASE AGAIN AS MODELS DEPICTED. HOWEVER...WITH TEMPS WELL ABOVE
FREEZING IN OUR FAR SW COUNTIES...SUSPECT THAT WHAT FALLS THERE WILL
INDEED BE MIXED WITH OR IN THE FORM OF RAIN LATE TODAY. THIS ROUND OF
PRECIP EXITS TO THE EAST THIS EVENING...WITH LITTLE ADDITIONAL PRECIP
EXPECTED OVERNIGHT. ANOTHER ROUND OF LIGHT SNOW IS EXPECTED TO MOVE
THROUGH FROM WEST TO EAST...ESPECIALLY IN OUR SOUTHERN COUNTIES....ON
SUNDAY MORNING. HOWEVER...PRECIP SHOULD BE LIGHT...WITH SOME QUESTION
AS TO HOW MANY PLACES WILL ACTUALLY MEASURE. IN LIGHT OF THIS...WILL
UPDATE THE WINTER WX ADVISORY TO ALLOW A STEPPED EXPIRATION FROM WEST
TO EAST THIS EVENING. HOPEFULLY...WHATEVER OCCURS ON SUNDAY MORNING
CAN BE HANDLED WITH AN SPS IF NECESSARY. THE SNOW ON SUNDAY SHOULD
THEN EXIT TO THE EAST...LEAVING JUST FLURRIES AROUND INTO SUNDAY
NIGHT. LAPSE RATES IN THE LOWEST LEVELS WILL BE STEEP THROUGH MOST OF
THE PERIOD. HOWEVER...THOSE STEEP LAPSE RATES WILL NOT EXTEND MUCH
PAST THE -10C LEVEL...AND LOW LEVEL FLOW WILL BE LARGELY
SOUTHWESTERLY OR WESTERLY WITH ONLY A PARTIAL UPSLOPE COMPONENT.
THESE FACTORS WILL LIKELY LIMIT UPSLOPE/ELEVATION ENHANCEMENT IN OUR
SOUTHEAST COUNTIES. ALTHOUGH...SOME ELEVATION DEPENDENCE MAY OCCUR
THROUGH THIS EVENING DUE TO SOME LOWER ELEVATIONS IN THE SOUTH BEING
ABOVE FREEZING.
.LONG TERM...(MONDAY THROUGH SATURDAY)
ISSUED AT 354 PM EST SAT FEB 2 2013
MODELS IN GOOD AGREEMENT WITH SIGNIFICANT PATTERN CHANGE AS MEAN
FLOW TRANSITIONS TO ZONAL BY MID WEEK. THIS WILL RESULT IN A CHANGE
FROM BELOW NORMAL TEMPERATURES TO NORMAL TEMPERATURES AND THEN ABOVE
NORMAL TEMPERATURES AS HEIGHTS RISE.
THERE WILL BE ONE LAST CLIPPER TYPE SYSTEM THAT WILL AFFECT THE AREA
LATE MONDAY INTO TUESDAY. PRECIPITATION TYPE WILL BE PROBLEMATIC
WITH THIS AS BOUNDARY LAYER WILL BE MUCH WARMER THAN WITH THE
SYSTEMS THAT AFFECTED THE AREA THIS WEEKEND. AT THIS POINT IT LOOKS
LIKE BEST CHANCE FOR SNOW WILL BE ACROSS NORTHERN KY...WITH
RAIN MORE LIKELY IN THE SOUTHERN PART OF THE STATE.
AFTER THE PASSAGE OF THIS SYSTEM HIGH PRESSURE WILL BRING DRY AND
WARMER WEATHER FOR THE MIDDLE OF THE WEEK. PRECIPITATION
CHANCES...IN THE FORM OF RAIN SHOWERS...WILL RETURN AT THE END OF
THE WEEK AS LOW PRESSURE MOVES ACROSS THE GREAT LAKES AND A COLD
FRONT MOVES THROUGH EASTERN KY.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SUNDAY NIGHT)
ISSUED AT 150 AM EST SUN FEB 3 2013
THE CIGS AND VSBY SHOULD STAY UP AT THE TAF SITES THROUGH THE NEXT
SEVERAL HOURS. THE NEXT MID LEVEL WAVE WILL MOVE INTO THE AREA
TOWARDS DAWN WITH RENEWED SNOW SHOWERS EXPECTED. WITH THIS...EXPECT
CIGS TO LOWER INTO IFR OR WORSE CONDITIONS WITH VIS FOLLOWING SUIT AS
THE SNOW MOVES IN. AFTER THE SNOW TAPERS OFF BY MID-MORNING...EXPECT
MVFR CIGS AT AROUND 1500 FT TO HANG ON THROUGH THE END OF THE PERIOD.
WINDS WILL BE FROM THE WEST AT 5 TO 10 KTS THROUGH TONIGHT...THOUGH
OCCASIONAL GUSTS TO 15 KTS WILL BE POSSIBLE...ASSOCIATED WITH ANY
HEAVIER SNOW BAND...EARLY TODAY.
&&
.JKL WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...GREIF
SHORT TERM...HAL
LONG TERM....SBH
AVIATION...GREIF
AREA FORECAST DISCUSSION
NWS LOUISVILLE KY
1246 AM EST SUN FEB 03 2013
...Updated Aviation Discussion...
.Forecast Update...
Issued at 1100 PM EST Sat Feb 2 2013
Current forecast continues to be on track this evening. IR
satellite imagery continues to show breaks in the clouds over our
western and southwestern sections this evening. This has allowed
temperatures to cool into the lower 30s. Elsewhere, temperatures
generally remained around 30 with some upper 20s in the Bluegrass
region.
Next clipper system is on its way toward the Ohio Valley this
evening. The feature is currently over northern Missouri with a
swath of snow ahead and just to the east of the feature. Last
several runs of the HRRR and RAP models suggest that this swath of
snow will generally head southeast and only affect our
western/southwestern areas. The latest NAM runs remain quite
consistent in bringing the snow band southeast into our
southern/southwestern areas as well, but also expand the snowfall to
the east and northeast after sunrise as the wave deepens slightly as
it rounds the base of the upper trough axis.
Based on upstream radar trends, trajectory analysis suggests that
the snow band will move through St. Louis shortly and then enter
western KY around 06Z...and then into central Kentucky in the 07-09Z
time frame. Upstream reports so far have been very light with only
trace to 1/2 inch amounts being reported northwest of St. Louis.
However, the band does seem to be increasing in intensity somewhat.
Latest NAM/GFS guidance continues to produce a little over a tenth
of an inch of QPF overnight, mainly along a corridor from Hancock
county southeastward through Russell county. Given upstream
observations and trends, this looks fairly reasonable. With surface
temperatures expected to remain in the upper 20s to around 30 across
the southwest and a little bit of a warm nose aloft, snow ratios
will probably be around 13-15:1. This combined with the fast
movement of the wave will keep snowfall amounts on the low side.
Still think that an inch or less of accumulation looks like a good
bet. However, some isolated higher amounts in the Hancock to
Russell county corridor can not be ruled out where some heavier
bands may traverse the area. The combination of the snowfall along
with subfreezing temperatures supports keeping the traveler`s
advisory going overnight.
Update issued at 744 PM EST Sat Feb 2 2013
Area radars show that the light snow has come to an end across the
area this evening. IR satellite imagery shows a little bit of
clearing moving into the western sections of the forecast area. So,
areas west of I-65 will see a period of clear skies which should
allow temperatures to fall off a little quicker than forecast.
Mostly cloudy skies with a few scattered flurries will be possible
in the Bluegrass region over the next hour or so. With
precipitation coming to an end, the Winter Weather Advisory was
allowed to expire at 700 PM EST.
After a very brief break in the weather this evening and into the
early overnight period, attention now turns to a clipper system to
our northwest. Mosaic radars show this wave pushing down through
southern Iowa and into northern Missouri at this time. The short
term guidance continue to be in good agreement with bringing this
clipper into western Kentucky late tonight and then through our CWA
probably after 2-3 AM EST. While the model data suggests that our
western/southwest sections would take the brunt of this clipper,
radar signatures and real time observations generally suggest that
our whole CWA would be in play for snow overnight. Given the fast
movement of the system, a quick hitting shot of snow seems very
likely, but the speed at which the system is moving will likely cut
down accumulations. Current thinking is that an inch or less of
snowfall will be likely with this system coming through, though some
areas in our southwest that have missed out on the snow of late, may
get their turn tonight.
With the light snow expected along with surface temps below
freezing, the snow will accumulate, so some slick spots are likely
to develop late tonight. For this reason, a traveler`s advisory has
been issued for the entire forecast area for the overnight and
Sunday morning time frame.
Will continue to monitor upstream observations and trends this
evening. If a more significant snowfall threat becomes more clear,
a new winter weather advisory may be required in later forecast
updates.
&&
.Short Term (Tonight through Sunday night)...
Issued at 300 PM EST Sat Feb 2 2013
Within a broad cyclonic northwestern flow across the region, a
series of weak disturbances will threaten to bring continued
flurries or light snow showers through mid-day Sunday.
Currently, a weak trough is moving across southern Indiana.
Flurries, or very light snow showers will continue over southern
Indiana and overspread the Bluegrass Region late this afternoon,
diminishing from west to east by early evening. Little or no
additional accumulations are expected, although some of the heavier
snow showers may produce a dusting across the Bluegrass this evening.
Will allow our winter weather advisory to expire at 7 pm this
evening, when the last of our evening snow showers depart. Some
slightly cooler and drier air will briefly arrive later this
evening.
The last of our series of clippers will bring increasing cloudiness
and a chance of light snow across central Kentucky around or shortly
after dawn. Precipitation amounts will not amount to much. But
forecast soundings, even at Bowling Green, hint at some light snow.
If this weak system organizes and tracks over central Kentucky, an
addition half inch of snow is possible.
Expect clearing skies by Sunday afternoon. Brisk west winds will
develop as high pressure builds across the southern plains. Winds
will increase to 10 to 20 mph by afternoon with some gusts near 25
mph. As high pressure moves overhead Sunday night, expect mostly
clear skies and chilly temperatures, especially across snow covered
southern Indiana and the Bluegrass.
.Long Term (Monday through Saturday)...
Issued at 300 PM EST Sat Feb 2 2013
The clipper system for Monday evening still looks on track as far as
timing goes. The latest NAM has come in more robust with QPF
amounts but still nothing greater than a quarter of an inch. P-type
profiles look a little warmer than previously advertised with the
majority of locations over southern Indiana/central KY starting out
as rain Monday afternoon. Some southern Indiana locations may see a
mix of rain and snow. As colder air pushes in Monday night, precip
type will change over to either some light snow before ending or
perhaps some light freezing drizzle or sleet depending on how fast
moisture aloft decreases. If a snowier soln works out, still looks
like southern Indiana/northern KY could see 1-2 inches of snow.
However, the latest model soundings indicate a slightly warmer soln
resulting in mostly cold rain over the area with a mixed bag of
precip to end the event Monday night. Stay tuned!
Another surface ridge edges into the region late Tuesday into
Wednesday, shutting off all precipitation. With clear skies and the
surface ridge nearby, Wednesday morning will be rather chilly, with
lows in the 20s to perhaps upper teens. Heights will begin to
rise ahead of the next system on Wednesday into Thursday, which
should help temperatures moderate into the upper 40s and lower 50s
by Thursday.
Another quick-moving shortwave will induce a surface low across the
southern Great Lakes late Thursday into Friday. This system will
drive a cold front through the Ohio Valley early Friday morning.
The precipitation looks to be mostly rain with this disturbance as
it barrels through. Slightly cooler air will filter in behind the
front for Friday, as temperatures drop back into the mid and upper
40s.
&&
.Aviation (06Z TAF Issuance)...
Issued at 1240 AM EST Sun Feb 3 2013
Main challenge is once again timing and intensity of snow as another
clipper races ESE through the Ohio Valley. Upstream obs around STL
show a decent snow shield with IFR or even LIFR conditions. However,
this could be quite localized and sneak in between BWG and SDF as it
moves through in the pre-dawn hours.
Will advertise IFR conditions in BWG starting around 09Z, as the
snow in these clippers has been quick to knock down visibilities.
Think most of the action will stay south of SDF and LEX, but have
gone with MVFR conditions there, with SDF just barely going into
fuel-alternate.
Once the upper impulse is to our east, conditions should improve to
VFR on gusty WNW winds around midday. LEX could hang on to high-end
MVFR. Light winds and clearing skies on Sunday evening.
&&
.LMK WATCHES/WARNINGS/ADVISORIES...
IN...NONE.
KY...NONE.
$$
Update...........MJ
Short Term.......JSD
Long Term........AMS
Aviation.........RAS
AREA FORECAST DISCUSSION
NWS LOUISVILLE KY
1100 PM EST SAT FEB 02 2013
.Forecast Update...
Issued at 1100 PM EST Sat Feb 2 2013
Current forecast continues to be on track this evening. IR
satellite imagery continues to show breaks in the clouds over our
western and southwestern sections this evening. This has allowed
temperatures to cool into the lower 30s. Elsewhere, temperatures
generally remained around 30 with some upper 20s in the Bluegrass
region.
Next clipper system is on its way toward the Ohio Valley this
evening. The feature is currently over northern Missouri with a
swath of snow ahead and just to the east of the feature. Last
several runs of the HRRR and RAP models suggest that this swath of
snow will generally head southeast and only affect our
western/southwestern areas. The latest NAM runs remain quite
consistent in bringing the snow band southeast into our
southern/southwestern areas as well, but also expand the snowfall to
the east and northeast after sunrise as the wave deepens slightly as
it rounds the base of the upper trough axis.
Based on upstream radar trends, trajectory analysis suggests that
the snow band will move through St. Louis shortly and then enter
western KY around 06Z...and then into central Kentucky in the 07-09Z
time frame. Upstream reports so far have been very light with only
trace to 1/2 inch amounts being reported northwest of St. Louis.
However, the band does seem to be increasing in intensity somewhat.
Latest NAM/GFS guidance continues to produce a little over a tenth
of an inch of QPF overnight, mainly along a corridor from Hancock
county southeastward through Russell county. Given upstream
observations and trends, this looks fairly reasonable. With surface
temperatures expected to remain in the upper 20s to around 30 across
the southwest and a little bit of a warm nose aloft, snow ratios
will probably be around 13-15:1. This combined with the fast
movement of the wave will keep snowfall amounts on the low side.
Still think that an inch or less of accumulation looks like a good
bet. However, some isolated higher amounts in the Hancock to
Russell county corridor can not be ruled out where some heavier
bands may traverse the area. The combination of the snowfall along
with subfreezing temperatures supports keeping the traveler`s
advisory going overnight.
Update issued at 744 PM EST Sat Feb 2 2013
Area radars show that the light snow has come to an end across the
area this evening. IR satellite imagery shows a little bit of
clearing moving into the western sections of the forecast area. So,
areas west of I-65 will see a period of clear skies which should
allow temperatures to fall off a little quicker than forecast.
Mostly cloudy skies with a few scattered flurries will be possible
in the Bluegrass region over the next hour or so. With
precipitation coming to an end, the Winter Weather Advisory was
allowed to expire at 700 PM EST.
After a very brief break in the weather this evening and into the
early overnight period, attention now turns to a clipper system to
our northwest. Mosaic radars show this wave pushing down through
southern Iowa and into northern Missouri at this time. The short
term guidance continue to be in good agreement with bringing this
clipper into western Kentucky late tonight and then through our CWA
probably after 2-3 AM EST. While the model data suggests that our
western/southwest sections would take the brunt of this clipper,
radar signatures and real time observations generally suggest that
our whole CWA would be in play for snow overnight. Given the fast
movement of the system, a quick hitting shot of snow seems very
likely, but the speed at which the system is moving will likely cut
down accumulations. Current thinking is that an inch or less of
snowfall will be likely with this system coming through, though some
areas in our southwest that have missed out on the snow of late, may
get their turn tonight.
With the light snow expected along with surface temps below
freezing, the snow will accumulate, so some slick spots are likely
to develop late tonight. For this reason, a traveler`s advisory has
been issued for the entire forecast area for the overnight and
Sunday morning time frame.
Will continue to monitor upstream observations and trends this
evening. If a more significant snowfall threat becomes more clear,
a new winter weather advisory may be required in later forecast
updates.
&&
.Short Term (Tonight through Sunday night)...
Issued at 300 PM EST Sat Feb 2 2013
Within a broad cyclonic northwestern flow across the region, a
series of weak disturbances will threaten to bring continued
flurries or light snow showers through mid-day Sunday.
Currently, a weak trough is moving across southern Indiana.
Flurries, or very light snow showers will continue over southern
Indiana and overspread the Bluegrass Region late this afternoon,
diminishing from west to east by early evening. Little or no
additional accumulations are expected, although some of the heavier
snow showers may produce a dusting across the Bluegrass this evening.
Will allow our winter weather advisory to expire at 7 pm this
evening, when the last of our evening snow showers depart. Some
slightly cooler and drier air will briefly arrive later this
evening.
The last of our series of clippers will bring increasing cloudiness
and a chance of light snow across central Kentucky around or shortly
after dawn. Precipitation amounts will not amount to much. But
forecast soundings, even at Bowling Green, hint at some light snow.
If this weak system organizes and tracks over central Kentucky, an
addition half inch of snow is possible.
Expect clearing skies by Sunday afternoon. Brisk west winds will
develop as high pressure builds across the southern plains. Winds
will increase to 10 to 20 mph by afternoon with some gusts near 25
mph. As high pressure moves overhead Sunday night, expect mostly
clear skies and chilly temperatures, especially across snow covered
southern Indiana and the Bluegrass.
.Long Term (Monday through Saturday)...
Issued at 300 PM EST Sat Feb 2 2013
The clipper system for Monday evening still looks on track as far as
timing goes. The latest NAM has come in more robust with QPF
amounts but still nothing greater than a quarter of an inch. P-type
profiles look a little warmer than previously advertised with the
majority of locations over southern Indiana/central KY starting out
as rain Monday afternoon. Some southern Indiana locations may see a
mix of rain and snow. As colder air pushes in Monday night, precip
type will change over to either some light snow before ending or
perhaps some light freezing drizzle or sleet depending on how fast
moisture aloft decreases. If a snowier soln works out, still looks
like southern Indiana/northern KY could see 1-2 inches of snow.
However, the latest model soundings indicate a slightly warmer soln
resulting in mostly cold rain over the area with a mixed bag of
precip to end the event Monday night. Stay tuned!
Another surface ridge edges into the region late Tuesday into
Wednesday, shutting off all precipitation. With clear skies and the
surface ridge nearby, Wednesday morning will be rather chilly, with
lows in the 20s to perhaps upper teens. Heights will begin to
rise ahead of the next system on Wednesday into Thursday, which
should help temperatures moderate into the upper 40s and lower 50s
by Thursday.
Another quick-moving shortwave will induce a surface low across the
southern Great Lakes late Thursday into Friday. This system will
drive a cold front through the Ohio Valley early Friday morning.
The precipitation looks to be mostly rain with this disturbance as
it barrels through. Slightly cooler air will filter in behind the
front for Friday, as temperatures drop back into the mid and upper
40s.
&&
.Aviation (00Z TAF Issuance)...
Issued at 645 PM EST Sat Feb 2 2013
Through the remainder of this evening, expect cloudy skies and west
to west-northwesterly winds to prevail at all three TAF sites; in
other words, VFR conditions. However, this lull will be relatively
short-lived as another disturbance moves through the region
overnight into early Sunday morning. Snow showers will once again
bring some additional minor accumulations and reduce visibilities at
area terminals. The current thinking in timing of arrival is around
09Z for both the SDF and BWG sites and closer to 11Z for LEX. Right
now, have simply put in VCSH as a heads but the forecast will
certainly be updated later tonight to reflect possible drops in
flight categories as a result of the approaching snow. This burst of
snow activity should wind down by mid-morning Sunday, exiting off
toward the east. In its wake, gusty northwesterly winds will be the
primary aviation hazard through much of the day tomorrow behind the
disturbance.
&&
.LMK WATCHES/WARNINGS/ADVISORIES...
IN...NONE.
KY...NONE.
$$
Update...........MJ
Short Term.......JSD
Long Term........AMS
Aviation.........LG
AREA FORECAST DISCUSSION
NWS GRAY ME
258 AM EST SUN FEB 3 2013
.SYNOPSIS...
LOW PRESSURE WILL DEVELOP IN THE ATLANTIC WELL EAST OF THE REGION
TODAY AND MOVE NORTHEAST. A COLD...BRISK FLOW WILL BEGIN ON
MONDAY...FOLLOWED BY THE PASSAGE OF A WEAK RIDGE OF HIGH PRESSURE
THROUGH MIDWEEK. LOW PRESSURE WILL APPROACH THE MID ATLANTIC
REGION THURSDAY AND HEAD NORTHEAST.
&&
.NEAR TERM /THROUGH TODAY/...
WEAK LEAD S/WV TROF LIFTING THRU THE LARGER ERN L/WV TROF IS
SUPPORTING A WEAK LOW PRES SKIRTING THRU THE GULF OF MAINE. CLOUD
SHIELD IS ROUGHLY BISECTING THE CWFA...WITH VERY LIGHT SN
OCCURRING ACROSS SERN NH AND EXTREME SWRN ME. GENERALLY HAVE SCHC
TO CHC POP FOR COASTAL ZONES TODAY...AS OVERALL SYSTEM
ORGANIZATION WILL BE LACKING.
ONE FEATURE OF NOTE IS THE SFC TROF THAT EXTENDS BACK TO THE NW OF
THE WEAK LOW PRES CENTER. WINDS ARE NW AT MISM1...KLEW...AND KPWM.
WHILE AT KSFM AND IOSN3 WINDS ARE WSW. WITHIN THIS TROF...MORE
CONVECTIVE SHSN HAVE BEEN OCCURRING AND PROPAGATING WITH THE LLVL
FLOW. SOME BRIEFLY HEAVIER SNOWFALL RATES ARE PSBL IN ANY OF THESE
SHSN. MESOSCALE MODEL GUIDANCE WAS HANDLING THIS FEATURE VERY WELL
THIS MORNING...WITH THE HRRR AND LOCAL WRF FEATURING HIGH POP
WITHIN THE TROF AXIS. HAVE STARTED POP GRIDS HERE AND BLENDED
TOWARDS THIS AFTN. AS STRONGER S/WV TROF OFF THE MIDATLANTIC
REIGNITES SFC CYCLOGENESIS S OF NEW ENGLAND TODAY...WINDS WILL
BEGIN TO BECOME MORE NLY AND NELY ACROSS THE CWFA AND WATERS.
MESOSCALE MODELS FAVOR SHSN CONTINUING WITH THE WEAK SFC TROF AS
IT PUSHES BACK TO THE SW TODAY. THIS COULD KEEP THE NH SEACOAST
AND EXTREME SWRN ME IN THE SHSN A LITTLE LONGER THAN THE REST OF
THE COAST. HAVE LINGERED THE CHC POP IN THIS AREA INTO THE AFTN TO
ACCOUNT FOR THIS POSSIBILITY.
OTHERWISE...UPSLOPE SHSN GRADUALLY WIND DOWN THIS MORNING. A FEW
POCKETS WHERE CLOUDS SCATTER OUT WILL RADIATE WELL...AND LOWS WILL
APPROACH SUB-ZERO. THIS AFTN...CIRRUS SHIELD WILL PREVENT IDEAL
DIURNAL HEATING...AND HIGHS IN THE 20S TO NEAR 30 ARE A BLEND OF
THE MAV AND LOCAL WRF GUIDANCE.
&&
.SHORT TERM /TONIGHT THROUGH 6 PM MONDAY/...
UPR TROF CROSSES THE AREA OVERNIGHT INTO MON. WILL SEE CLOUDS
INCREASE AHEAD OF IT...ALONG WITH MORE WIDESPREAD
SHSN. THIS IS ESPECIALLY TRUE IN THE MTNS...WHERE DEVELOPING WLY
FLOW WILL SET OFF ANOTHER ROUND OF UPSLOPE SN. THE PROGRESSIVE
FLOW WILL KICK SFC LOW PRES WELL OUT TO SEA THOUGH...AND HAVE CUT
BACK ON AREA OF CHC POP FOR A LARGE PORTION OF THE CWFA. GREATEST
THREAT FOR STEADIER PCPN WILL BE ON THE MIDCOAST...WHERE LOW PRES
CUTTING WWD ACROSS THE BAROCLINIC ZONE AS IT RAPIDLY DEEPENS MAY
PASS CLOSER ENOUGH TO DOWNEAST MAINE TO BRUSH AREAS AROUND
PENOBSCOT BAY WITH -SN.
WITH THE PASSAGE OF THE UPR TROF...STRONG CAA KICKS IN EARLY MON.
DEEP MIXING LAYER WILL SUPPORT STRONGER WIND GUSTS TO TRANSLATE TO
THE SFC. ATTM GUSTS AROUND 30 KTS LOOK LIKELY...WITH A LOW
PROBABILITY FOR HIGHER GUSTS DEPENDING ON EXACT STRENGTH AND
TRACK OF LOW PRES. THE CLOSER TO THE CWFA...THE TIGHTER THE PRES
GRADIENT WILL BE.
&&
.LONG TERM /MONDAY NIGHT THROUGH SATURDAY/...
A BRISK NORTHWEST FLOW WILL ALLOW FOR MORE ARCTIC AIR TO ENTER THE
REGION MONDAY NIGHT BEHIND A DEPARTING FULL FLEDGED STORM OVER THE
CANADIAN MARITIMES. WITH THE EXCEPTION OF A FEW FLURRIES FROM A
SYSTEM WELL OFF THE EAST COAST ON WEDNESDAY...EXPECT DRY AND
MAINLY CLEAR CONDITIONS. MORE MOISTURE AND CLOUDINESS WILL HANG UP
IN THE MOUNTAINS HOWEVER DURING THIS PERIOD.
ALL BETS ARE OFF LATE IN THE WEEK AS THERE ARE GREAT DISCREPANCIES
WITH THE 00Z MODEL RUN. THE GGEM AND GFS BRING A SYSTEM TO OUR
WEST THURSDAY NIGHT INTO FRIDAY. THE LATEST EURO RUN IS MUCH MORE
WELL DEFINED WITH A STRONG EAST COAST LOW OVER THE DELMARVA REGION
BY 12Z FRIDAY. THIS SYSTEM SLOWLY MOVES NORTHEAST...WITH A BLOCKING
HIGH TO THE NORTH OF MAINE DURING THIS PERIOD. FOR THE TIME
BEING...WE HAVE CHANCE POPS FOR THIS SYSTEM FOR THE DAY 6 PERIOD.
INTERESTED TO SEE IF THE 12Z RUNS HOLD ONTO THIS SLOW MOVING
FEATURE. ASTRONOMICAL TIDES WILL BE RELATIVELY HIGH DURING THIS
PERIOD AS WELL.
&&
.AVIATION /07Z SUNDAY THROUGH THURSDAY/...
SHORT TERM...AREAS OF MVFR WITH LOCAL IFR CONDS THIS MORNING ALONG
COAST. DIVIDING LINE WILL BE BETWEEN KCON AND KPSM...RUNNING ENE
THRU KAUG AND KRKD. N OF THIS LINE EXPECT NO PCPN...EXCEPT FOR
KHIE WHERE UPSLOPE SHSN WILL GRADUALLY WIND DOWN THIS MORNING.
BECOMING VFR THIS AFTN
LATE SUN THERE IS A LOW PROBABILITY OF MVFR OR IFR SN TO WORK INTO
KRKD IN ASSOCIATION WITH AN OCEAN LOW PRES. MORE LIKELY IS THAT
BEHIND LOW PRES ON MON STRONG WLY WINDS DEVELOP...WITH GUSTS AOA
25 KT. UPSLOPE SHSN WILL BEGIN AGAIN FOR KHIE AND KLEB LATE SUN
THRU MON.
LONG TERM...CONDITIONS MAY DETERIORATE ONCE AGAIN BY FRIDAY AS LOW
PRESSURE APPROACHES.
&&
.MARINE...
SHORT TERM...WINDS AND SEAS REMAIN BELOW SCA THRESHOLDS ATTM.
DEVELOPING LOW PRES S OF NEW ENGLAND TODAY WILL CREATE NE FLOW ON
THE WATERS THRU THIS AFTN. COULD SEE WINDS APPROACH SCA GUSTS
LATER TODAY AS A RESULT. WITH THE PASSAGE OF A COLD FNT
MON...STRONG WLY FLOW WILL DEVELOP DURING THE MORNING AND INTO THE
AFTN. WINDS COULD GUST ABOVE GALE FORCE INTO TUE.
LONG TERM...GALES ARE POSSIBLE ONCE AGAIN ON FRIDAY.
&&
.GYX WATCHES/WARNINGS/ADVISORIES...
ME...NONE.
NH...NONE.
MARINE...GALE WATCH FROM MONDAY MORNING THROUGH LATE MONDAY NIGHT FOR
ANZ150>154.
&&
$$
LEGRO/JC
AREA FORECAST DISCUSSION...UPDATED
NWS GRAY ME
1224 AM EST SUN FEB 3 2013
.SYNOPSIS...
A WEAK LOW OVER NEW YORK STATE THIS AFTERNOON WILL CROSS THE
REGION LATER THIS EVENING. A SECOND LOW WILL DEVELOP IN THE
ATLANTIC WELL EAST OF THE REGION SUNDAY AND MOVE NORTHEAST. A
COLD...BRISK FLOW WILL BEGIN ON MONDAY...FOLLOWED BY THE PASSAGE
OF A WEAK RIDGE OF HIGH PRESSURE THROUGH MIDWEEK.
&&
.NEAR TERM /THROUGH TODAY/...
UPDATE...HAVE GONE AHEAD AND BUMPED POP UPWARDS ALONG THE COAST
USING THE LATEST HRRR RUN...WHICH SEEMED TO HAVE A GOOD HANDLE ON
WHERE IT IS CURRENTLY SNOWING ACROSS THE MIDCOAST. BACK TO THE SW
HAVE ALSO INCREASE POP TO CHANCE...WHERE OBS UPSTREAM IN SRN NEW
ENGLAND ARE REPORTING SOME -SN. WEAK TROF HAS ALSO SET UP OVER
SWRN ME...WHERE ENOUGH CONVERGENCE COULD SQUEEZE OUT SOME SHSN AS
WELL.
PREVIOUS DISCUSSION...A WEAK SYSTEM WILL AFFECT PORTIONS OF THE
AREA THIS EVENING WITH SOME VERY LIGHT SNOW AS IT MOVES EAST. BOTH
THE GFS AND NAM SHOW AN INITIAL WEAK DISTURBANCE BRINGING SOME
LIGHT SNOW TO WESTERN NEW HAMPSHIRE AND THE MOUNTAINS OF MAINE AND
NEW HAMPSHIRE. THIS WEAK SYSTEM IS STARVED FOR MOISTURE SO
ACCUMULATIONS WILL BE AN INCH OR LESS. THE MODELS ALSO SHOWING A
WEAK AREA OF CYCLONIC FLOW DEVELOPING ALONG THE MIDCOAST AS THE
PRIMARY DISTURBANCE MOVES EAST. THIS COULD PRODUCE AN INCH OR LESS
OF SNOW DURING THE EVENING PERIOD. ELSEWHERE...ONLY FLURRIES ARE
EXPECTED AS THE DISTURBANCE MOVES THROUGH. A WEAK RIDGE OF HIGH
PRESSURE WILL BRING ANY PRECIPITATION TO AN END AFTER MIDNIGHT
WITH PARTIAL CLEARING EXPECTED AWAY FROM THE COAST.
&&
.SHORT TERM /TONIGHT THROUGH 6 PM MONDAY/...
SKIES SHOULD START OUT PARTLY SUNNY ACROSS INLAND AREAS...BUT
CLOUDS WILL BE ON THE INCREASE DURING THE DAY AS A LARGE OCEAN
STORM DEVELOPS AND STARTS MOVING NORTHEAST. AT THIS TIME...IT
APPEARS THE STORM WILL BE TOO FAR EAST TO PRODUCE ANY SIGNIFICANT SNOW
ACROSS THE AREA. AT THE MOMENT...BEST CHANCE FOR ANY ACCUMULATING
SNOW WILL BE ALONG THE MIDCOAST. MODELS AREN`T IN TOTAL AGREEMENT
ON TRACK...BUT GENERALLY KEEP THE SIGNIFICANT PRECIPITATION WELL
OFFSHORE. AS THE LOW DEEPENS SUNDAY NIGHT...A STRONG NORTHERLY
FLOW WILL DEVELOP ACROSS THE AREA WITH SNOW SHOWERS POSSIBLE.
&&
.LONG TERM /MONDAY NIGHT THROUGH SATURDAY/...
LONG TERM FORECAST IS PRETTY QUIET WITH NO SIGNIFICANT STORM
SYSTEMS EXPECTED TO PROVIDE PRECIPITATION THROUGH AT LEAST THE
MIDDLE OF THE WEEK. TEMPERATURES STAY GENERALLY AT OR BELOW NORMAL
THROUGH MIDWEEK BEFORE WARMING A BIT ABOVE NORMAL.
AS LOW PRESSURE STRENGTHENS AND MOVES NORTH WELL OFF THE COAST...
A WESTERLY FLOW WILL DEVELOP BEHIND IT OVER NEW ENGLAND ON MONDAY.
WITH A STRONG JET OVER THE AREA... EXPECT WINDS TO BE GUSTY WITH
OCCASIONAL GUSTS NEAR WIND ADVISORY LEVELS POSSIBLE. THE WIND
GUSTS WILL CONTINUE INTO MONDAY NIGHT AS COLD AIR MOVES IN ON THE
WEST TO NORTHWEST FLOW.
THE BRUNT OF THE COLD DOES NOT LAST LONG AND MAINLY IMPACTS
NORTHERN PARTS OF THE REGION. AS A RESULT... EXPECT HIGH
TEMPERATURES ON TUESDAY ONLY 5-10 DEGREES BELOW NORMAL... WITH
LOWS FALLING INTO THE SINGLE DIGITS NEAR THE COAST AND AS COLD AS
-10 IN THE INTERIOR. AS BROAD HIGH PRESSURE MOVES EAST... EXPECT
GRADUALLY WARMING TEMPERATURES THROUGH THURSDAY. A WAVE EMBEDDED
IN THE BROADER ZONAL FLOW ALOFT WILL TRACK ACROSS NEW ENGLAND ON
FRIDAY PROVIDING A CHANCE FOR RAIN/SNOW ACROSS THE REGION.
&&
.AVIATION /05Z SUNDAY THROUGH THURSDAY/...
SHORT TERM...MAINLY VFR CONDITIONS THROUGH THE PERIOD. SOME MVFR
CONDITIONS POSSIBLE THIS EVENING IN AREAS OF LIGHT SNOW AND AGAIN
SUNDAY EVENING ALONG THE MIDCOAST IN LIGHT SNOW.
LONG TERM...VFR CONDITIONS EXPECTED THROUGH MIDWEEK. WEST TO
NORTHWEST WINDS ON MONDAY WILL GUST TO 30 KT OR MORE THROUGH
MONDAY EVENING.
&&
.MARINE...
SHORT TERM...WINDS AND SEAS WILL BE ON THE INCREASE LATE SUNDAY AND
SUNDAY NIGHT AS AN OCEAN STORM DEVELOPS RAPIDLY EAST OF THE WATERS
AND MOVES NORTHEAST.
LONG TERM...EXPECT WINDS TO INCREASE TO GALE FORCE ON MONDAY AND
LAST THROUGH EARLY THURSDAY MORNING. GUSTS TO 45 KT ARE POSSIBLE
AS A STRONG JET BRINGS COLDER AIR IN FROM THE WEST NORTHWEST.
&&
.GYX WATCHES/WARNINGS/ADVISORIES...
ME...NONE.
NH...NONE.
MARINE...GALE WATCH FROM MONDAY MORNING THROUGH LATE MONDAY NIGHT FOR
ANZ150>154.
&&
$$
NEAR TERM...LEGRO
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
1156 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 06Z TAFS THROUGH 06Z SUNDAY NIGHT)
ISSUED AT 1153 PM EST SAT FEB 2 2013
AT KCMX...AS ANOTHER UPPER LEVEL DISTURBANCE/SFC TROF APPROACH
OVERNIGHT...MORE -SN/MVFR CONDITIONS WILL DEVELOP OVER THE NEXT FEW
HRS. AS THE TROF PASSES TOWARD 12Z...EXPECT A PERIOD OF MDT/HVY SHSN
WITH LIFR CONDITIONS FOR AT LEAST A COUPLE OF HRS. FOLLOWING THE
PASSAGE OF THE TROF/HEAVIER SHSN...LIFR CONDITIONS SHOULD THEN
LINGER THRU MID/LATE AFTN AS LAKE EFFECT SHSN/SMALL SNOW FLAKES/SOME
BLSN EFFECTIVELY REDUCE VIS. AS -SHSN DIMINISH A BIT LATE IN THE DAY
WITH LOWER INVERSION...CONDITIONS WILL PROBABLY SETTLE AT LOW IFR
FOR THE EVENING HRS.
AT KIWD...VFR CONDITIONS WILL GIVE WAY TO SOME -SN/MVFR CONDITIONS
LATER IN THE NIGHT WITH APPROACH OF DISTURBANCE/LOW PRES TROF. IFR
CONDITIONS WILL ACCOMPANY THE PASSAGE OF THE TROF AND THEN PERSIST
AS LAKE EFFECT SHSN SET UP UNDER NW WINDS BEHIND TROF. WINDS MAY
BEGIN TO BACK JUST ENOUGH LATER IN THE AFTN FOR CONDITIONS TO
IMPROVE TO MVFR.
AT KSAW...EXPECT VFR CONDITIONS TO PREVAIL OVERNIGHT AHEAD OF
APPROACHING LOW PRES TROF. MVFR CIGS AND FLURRIES ARE EXPECTED
FOLLOWING THE PASSAGE OF TROF THIS MORNING 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 UNTIL 7 AM EST MONDAY FOR LSZ244-
245-264.
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 ST LOUIS MO
340 AM CST SUN FEB 3 2013
.SHORT TERM...
ISSUED AT 330 AM CST SUN FEB 3 2013
(TODAY THROUGH TUESDAY)
THANKS TO A COMPACT AND POTENT NW FLOW VORT MAX...SOME RATHER
IMPRESSIVE LOW LEVEL FORCING AND A POCKET OF STEEP MID LEVEL LAPSE
RATES...A NICE BAND OF 2-4 INCHES OF SNOW FELL LAST NIGHT WITH THE
HIGHEST AMOUNTS CENTERED RIGHT THROUGH THE ST LOUIS METRO. KUDOS
TO THE SAT AFTERNOON RUNS OF THE HRRR WHICH WAS THE SOLE MODEL
THAT COMPLETELY NAILED THE SNOWFALL FORECAST. THE SNOW HAS LONG
ENDED AND THE ASSOCIATED SURFACE FRONTAL SYSTEM WAS PASSING THRU
FAR ERN MO AT THIS TIME. GOOD CAA IS EXPECTED THIS MORNING IN THE
WAKE OF THE COLD FRONT WITH STRATUS IN THE LOW LEVEL NW FLOW FROM
ERN MO INTO IL. CAA SHOULD CEASE BY MIDDAY AS THE SURFACE RIDGE
SHIFTS INTO THE AREA WITH WEAK WAA DEVELOPING DURING THE AFTERNOON
IN CENTRAL MO AS THE SURFACE RIDGE CONTINUES TO DEPART TO THE
EAST. IN RESPONSE THE CLOUDS SHOULD ALSO EXIT EASTWARD.
SOUTHERLY WINDS WILL BECOME ESTABLISHED ACROSS THE AREA THIS
EVENING IN THE WAKE OF THE DEPARTING HIGH AND IN ADVANCE OF THE
NEXT COLD FRONTAL SYSTEM...WITH STRONG LOW LEVEL WAA ENSUING
DURING THE LATE EVENING AND OVERNIGHT HOURS. THIS FLOW REGIME
COMBINED WITH INCREASING AND THICKENING CLOUDS OVERNIGHT WOULD
SUPPORT MIN TEMPS OCCURING DURING THE EVENING AND THEN RISING
OVERNIGHT. THE SNOW COVER COULD BE PROBLEMATIC IF THE SURFACE WINDS
REMAIN LIGHTER THAN EXPECTED...ALLOWING FOR A GREATER EVENING TEMP
FALL THAN CURRENTLY FCST. ATTM IT APPEARS THAT SHOWERS SHOULD
DEVELOP ACROSS ERN OK DURING THE OVERNIGHT HOURS AND SPREAD NEWD
ACROSS SE MO AND SRN IL BETWEEN 15-18Z MONDAY IN RESPONSE TO
INCREASING LARGE SCALE ASCENT AND STRONG LOW LEVEL MOISTURE
TRANSPORT/CONVERGENCE. GIVEN THE WAA REGIME AND EXPECTED ONSET OF
PCPN...SURFACE TEMPERATURES ARE EXPECTED TO BE ABOVE FREEZING AND
CONTINUE TO WARM THROUGH THE MORNING AHEAD OF THE FRONT...ALTHOUGH
THAT WARMING COULD BE RETARDED A BIT BY DIABATIC COOLING. STRONG
CAA IS EXPECTED IN THE WAKE OF THE COLD FRONT DRIVING SEWD THRU
THE MORNING AND EARLY AFTERNOON. HIGH PRESSURE WILL THEN BUILD
INTO THE AREA ON MONDAY NIGHT AND THEN YET ANOTHER NW FLOW SHORT
WAVE WILL BRING A WEAK FRONT THROUGH THE REGION ON TUESDAY.
GLASS
&&
.LONG TERM...
ISSUED AT 330 AM CST SUN FEB 3 2013
(WEDNESDAY THROUGH SATURDAY)
A BIG PATTERN CHANGE WILL EVOLVE DURING THIS PERIOD AS THE BROAD
LONG WAVE TROF THAT HAS BEEN SENDING US THE PARADE OF NW FLOW
SHORT WAVES FINALLY DEPARTS WELL INTO THE ATLANTIC. HEIGHTS ALOFT
RISE IN RESPONSE...WITH THE FLOW ALOFT BECOMING QUASI-ZONAL THRU
THE NATIONS MIDSECTION WITH EMBEDDED LOW AMPLITUDE SHORT WAVES. ONE
OF THESE WAVES WILL BRING ANOTHER COLD FRONT THROUGH ON THURSDAY
WITH AN ACCOMPANING CHANCE OF SHOWERS. THE FLOW ALOFT CONTINUES TO
EVOLVE THROUGH LATE WEEK WITH THE DEVELOPMENT OF A DEEP WRN TROF.
CURRENT INDICATIONS ARE THAT THIS TROF MAY BRING A THREAT OF
SHOWERS AND THUNDERSTORMS BY LATE NEXT WEEKEND AS AN INITIAL WAVE
MIGRATES INTO THE CENTRAL U.S.. OVERALL THE EXTENDED PERIOD SHOULD
BE MARKED BY ABOVE AVERAGE TEMPERATURES.
GLASS
&&
.AVIATION...
ISSUED AT 1117 PM CST SAT FEB 2 2013
A LOCALLY ENHANCED BAND OF SNOWFALL WAS MOVING OVER THE METRO AREA
TERMINALS AT TAF ISSUANCE HOWEVER PCPN SHOULD END WITHIN AN HOUR
OR TWO GIVEN HOW QUICKLY THE UPPER LEVEL DISTURBANCE IS MOVING.
PCPN HAS ENDED AT KCOU AND VFR CONDITIONS ARE EXPECTED FOR THE
REST OF THE NIGHT. PCPN HAS ALSO ENDED AT KUIN AND ALTHOUGH
REGIONAL RADAR IMAGERY DID SHOW AN AREA OF LIGHT SNOW OVER SERN IA
THAT WAS MOVING SEWD...ATTM IT APPEARS THAT KUIN WILL REMAIN JUST
TO THE SOUTHWEST OF THE PCPN. INITIALLY LIGHT WINDS WILL BECOME
NWLY AND INCREASE AFTER THE PASSAGE OF A CDFNT TONIGHT. NWLY WINDS
WILL PERSIST TOMORROW WITH GUSTS OF 20-30 KTS EXPECTED BY MID
MORNING BEFORE WINDS SUBSIDE BY LATE AFTN.
SPECIFICS FOR KSTL...A LOCALLY ENHANCED BAND OF SNOWFALL WAS
MOVING OVER KSTL AT TAF ISSUANCE HOWEVER PCPN SHOULD END WITHIN AN
HOUR OR TWO GIVEN HOW QUICKLY THE UPPER LEVEL DISTURBANCE IS
MOVING. INITIALLY LIGHT WINDS WILL BECOME NWLY AND INCREASE AFTER
THE PASSAGE OF A CDFNT TONIGHT. NWLY WINDS WILL PERSIST TOMORROW
WITH GUSTS OF 20-30 KTS EXPECTED BY MID MORNING BEFORE WINDS
SUBSIDE BY LATE AFTN.
KANOFSKY
&&
.LSX WATCHES/WARNINGS/ADVISORIES...
MO...NONE.
IL...NONE.
&&
$$
WFO LSX
AREA FORECAST DISCUSSION...UPDATED AVIATION
NWS ST LOUIS MO
1135 PM CST SAT FEB 2 2013
.UPDATE...
ISSUED AT 745 PM CST SAT FEB 2 2013
STRONG UPPER LEVEL DISTURBANCE...CLIPPER SYS...IS RACING TOWARDS
THE FA THIS EVENING. HEADING TOWARDS THE SFC...THERE IS ALSO AN
ACCOMPANYING FRONTAL SYS WITH THIS...IN THE FORM OF A WEAK LO PRES
STRAGGLING BEHIND IT AND A WRMFNT EXTENDING SWD AND A CDFNT
EXTENDING WWD.
THE CLIPPER SYS UPPER LEVEL PORTION IS SPLIT INTO TWO SECTIONS...
THE NRN PART OVER N-CNTRL IA...WHILE THE SRN PART IS OVER SWRN IA.
HRRR AND RAP DEVELOP THE SRN PART MORE EXTENSIVELY WITH TIME AND
EVENTUALLY THIS SHOULD BECOME THE DOMINANT PART AND WATCHING
DEVELOPMENT OF PCPN IN IA SEEMS TO BE CONFIRMING THIS. THEREFORE
IT LOOKS LIKE PCPN AXIS NEEDS TO BE SHIFTED MORE SWWD FOR THIS
STORM AS IT MOVES THRU THE FA...FROM NEAR MEXICO MO THRU THE STL
METRO AREA AND INTO SRN IL. NOT TO SAY IT WON/T PRECIPITATE
FURTHER NEWD...AS BROAD AREA SHOULD REMAIN LARGELY INTACT AS IT
MOVES THRU...BUT BETTER POTENTIAL FOR MORE DYNAMICALLY INDUCED
BANDS THRU THE AFOREMENTIONED AREAS THOUGH.
HOWEVER...UNFORTUNATELY...IT LOOKS LIKE PCPN-TYPE WILL NOT BE ALL
SNOW ON THE SWRN EDGE WHERE WE COULD SEE SOME BETTER BANDING. RAP
SOUNDINGS AS WELL AS NAM SUGGEST LO-ELEVATED WARM WEDGE OF AIR
AROUND 2-3KFT THAT WILL BE LOOSELY TIED TO THE SFC-TEMP IN THAT IT
SHOULD BE NEAR ISOTHERMAL BUT ENOUGH TO RESULT IN SOME SLEET AND
RAIN POTENTIAL AS WELL BUT ONLY ALONG THE EXTREME SWRN EDGE.
ELSEWHERE SHOULD BE MOSTLY IF NOT ALL SNOW.
UPDATED SNOW TOTALS REFLECT A MORE SWWD SHIFT...AND WILL SEE
WIDESPREAD HALF INCH TO INCH TOTALS FA-WIDE EXCEPT IN CNTRL AND
SERN MO. WHERE MESOSCALE BANDS SETUP...AND FALL AS SNOW...COULD
SEE OVER AN INCH...PERHAPS TWO. BUT TOO DIFFICULT TO NAIL DOWN
JUST YET.
SFC WRMFNT WILL THEN PUSH THRU LATER TONIGHT AND RESULT IN NEAR-
STEADY OR SLOWLY RISING TEMPS BUT THEN FOLLOWED BY CDFNT WHEREBY
WINDS WILL PICK UP AND BECOME GUSTY TO 25-30MPH AND WILL LAST THRU
SUNDAY MORNING BEFORE DIMINISHING.
TES
&&
.SHORT TERM...
ISSUED AT 329 PM CST SAT FEB 2 2013
(TONIGHT)
LAST NIGHT/S SYSTEM MOVED OUT FAIRLY QUICKLY...NOW NEXT IN A SERIES
OF SHORTWAVES TO SLIDE SOUTHEAST THROUGH FORECAST AREA TONIGHT.
CLOUDS ALREADY ON INCREASE WITH REGIONAL RADARS SHOWING MAIN AREA OF
SNOW ALREADY DEVELOPING OVER EASTERN SOUTH DAKOTA AND WESTERN MN...
TRACKING TO THE SOUTHEAST. SHOULD BEGIN TO MOVE INTO NORTHERN
PORTIONS OF FORECAST AREA BY 01Z AND QUICKLY SPREAD ACROSS FORECAST
AREA...WITH BEST CHANCES OVER EASTERN MO AND CENTRAL/SOUTHERN IL
THIS EVENING...THEN TAPER OFF AFTER MIDNIGHT. WITH MODELS IN GOOD
AGREEMENT ON STRENGTH...PLACEMENT AND TIMING OF THIS VIGOROUS
SHORTWAVE...UPPED POPS TO LIKELY FOR NORTHEAST/EAST CENTRAL MO AS
WELL AS WEST CENTRAL ILLINOIS. IT WILL BE A QUICK SHOT OF SNOW WITH
UP TO AN INCH POSSIBLE EAST OF MISSISSIPPI RIVER WITH A FAIRLY SHARP
CUTOFF ON SNOW VS NO SNOW TO THE WEST. AS SNOW TAPERS OFF...CLOUDS
TO BEGIN CLEARING OUT FROM WEST TO EAST TOWARDS DAYBREAK. AS FOR
LOWS TONIGHT...LOW 20S NORTHEAST PORTIONS TO UPPER 20S OVER CENTRAL
AND SOUTHEASTERN MISSOURI.
BYRD
&&
.LONG TERM...
ISSUED AT 329 PM CST SAT FEB 2 2013
(SUNDAY-THURSDAY)
UA PATTERN IS FORECAST BY ALL SOLUTIONS TO TRANSITION TO A ZONAL
FLOW REGIME OVER THE CENTRAL CONUS BY MIDWEEK...HOWEVER STRONG FLOW
ALOFT WILL CONTINUE THE PARADE OF FAST MOVING WEATHER SYSTEMS ACROSS
THE MID-MISSISSIPPI VALLEY.
TONIGHT`S CLIPPER SYSTEM SHOULD BE WELL EAST OF THE AREA BY 12Z
SUNDAY...WITH N-S SURFACE RIDGE RAPIDLY PRESSING THROUGH AREA SUNDAY
AFTERNOON AND EVENING. IN THE WAKE OF THE HIGH...THE NEXT SHORTWAVE
WILL RACE INTO THE MID MISSISSIPPI VALLEY ON MONDAY...WITH
ASSOCIATED SURFACE LOW AND COLD FRONT WORKING ACROSS THE CWA DURING
THE DAY. MODEL CYCLES EARLIER IN THE WEEK HAD BEEN TRYING TO BRING
THE FRONT THROUGH DRY...BUT LAST NIGHTS 00Z RUNS AND TODAYS 12Z
OUTPUT HAVE BEEN GENERATING CHANCE POPS WITH THIS FEATURE..WHICH
APPEARS REASONABLE GIVEN MOISTURE INCREASE PROGGED INTO AREA TIED TO
UVV WITH SHORTWAVE. HAVE GENERALLY MAINTAINED GOING FORECAST TRENDS
WITH CHANCE POPS OVER ABOUT THE SE HALF OF THE CWA.
THIS SYSTEM RACES EAST ON MONDAY EVENING...FOLLOWED BY ANOTHER
SURFACE RIDGE THAT WILL WORK INTO THE AREA WITH DRY AND TRANQUIL
WEATHER ON TUESDAY AND WEDNESDAY.
MEDIUM RANGE SOLUTIONS REMAIN IN FAIRLY GOOD AGREEMENT WITH THE
APPROACH OF THE NEXT SHORTWAVE ON THURSDAY...AND HAVE CONTINUED
CHANCE POPS ACROSS THE ENTIRE CWA WITH THIS FEATURE.
MODERATION OF AMS OVER REGION AS A RESULT OF THE TRANSITION OF THE
UA PATTERN SHOULD MEAN TEMPERATURES AT OR ABOVE AVERAGE FOR MUCH OF
THE PERIOD. ALTHOUGH A BRIEF SHOT OF COOL AIR BEHIND TONIGHT`S
CLIPPER MAY DELAY THIS MODERATION HIGHS SHOULD BE WELL IN THE 40S
MONDAY-WEDNESDAY...WITH S SECTIONS OF THE CWA CLIMBING INTO THE 50S
BY THURSDAY.
(FRIDAY-SATURDAY)
HEADING INTO THE END OF THE WEEK...ATTENTION TURNS TO STRONG STORM
SYSTEM THAT WILL BE MOVING FROM THE WESTERN U.S. INTO THE CENTRAL
PLAINS. WHILE THERE ARE SOME DIFFERENCES...MEDIUM RANGE GUIDANCE IS
SIMILAR ENOUGH WITH SPEED OF THIS SYSTEM TO WARRANT INCLUSION OF
POPS BY SATURDAY. WITH SURFACE LOW PROGGED THROUGH THE CENTRAL
PLAINS WE WILL BE ON THE WARM SIDE OF THE SYSTEM...SO PTYPE WILL BE
RAIN.
TRUETT
&&
.AVIATION...
ISSUED AT 1117 PM CST SAT FEB 2 2013
A LOCALLY ENHANCED BAND OF SNOWFALL WAS MOVING OVER THE METRO AREA
TERMINALS AT TAF ISSUANCE HOWEVER PCPN SHOULD END WITHIN AN HOUR
OR TWO GIVEN HOW QUICKLY THE UPPER LEVEL DISTURBANCE IS MOVING.
PCPN HAS ENDED AT KCOU AND VFR CONDITIONS ARE EXPECTED FOR THE
REST OF THE NIGHT. PCPN HAS ALSO ENDED AT KUIN AND ALTHOUGH
REGIONAL RADAR IMAGERY DID SHOW AN AREA OF LIGHT SNOW OVER SERN IA
THAT WAS MOVING SEWD...ATTM IT APPEARS THAT KUIN WILL REMAIN JUST
TO THE SOUTHWEST OF THE PCPN. INITIALLY LIGHT WINDS WILL BECOME
NWLY AND INCREASE AFTER THE PASSAGE OF A CDFNT TONIGHT. NWLY WINDS
WILL PERSIST TOMORROW WITH GUSTS OF 20-30 KTS EXPECTED BY MID
MORNING BEFORE WINDS SUBSIDE BY LATE AFTN.
SPECIFICS FOR KSTL...A LOCALLY ENHANCED BAND OF SNOWFALL WAS
MOVING OVER KSTL AT TAF ISSUANCE HOWEVER PCPN SHOULD END WITHIN AN
HOUR OR TWO GIVEN HOW QUICKLY THE UPPER LEVEL DISTURBANCE IS
MOVING. INITIALLY LIGHT WINDS WILL BECOME NWLY AND INCREASE AFTER
THE PASSAGE OF A CDFNT TONIGHT. NWLY WINDS WILL PERSIST TOMORROW
WITH GUSTS OF 20-30 KTS EXPECTED BY MID MORNING BEFORE WINDS
SUBSIDE BY LATE AFTN.
KANOFSKY
&&
.LSX WATCHES/WARNINGS/ADVISORIES...
MO...NONE.
IL...NONE.
&&
$$
WFO LSX
AREA FORECAST DISCUSSION...UPDATED
NWS GRAND FORKS ND
1116 PM CST SAT FEB 2 2013
.DISCUSSION...
WINDS HAVE DIMINISHED SIGNIFICANTLY IN THAT VALLEY CITY TO FORMAN
REGION IN SOUTHEASTERN NORTH DAKOTA AND THUS FEEL THE THREAT FOR
ANY REDUCED VISIBILITIES IN BLOWING SNOW IS NOW OVER. THUS DROPPED
THE ADVISORY WHICH WAS SET TO EXPIRE AT 06Z.
&&
.PREV DISCUSSION... /ISSUED 920 PM CST SAT FEB 2 2013/
DISCUSSION...
WILL CONTINUE WITH WINTER WX ADV FOR SOME BLOWING SNOW IN THE FAR
SOUTHWESTERN FCST AREA TIL 06Z. STRONGEST OF THE WINDS IN ERN SD
BUT STILL SOME GUSTS NR 30KTS VALLEY CITY TO GWINNER. BUT WINDS
DIMINISHING QUITE SOON LOOKING UPSTREAM AS PRESSURE RISE MOVES
INTO SW MINNESOTA. OTHERWISE...AREA OF CLEARING MOVING SOUTHEAST
INTO PARTS OF SE ND ATTM BUT CLOUDS IN CANADA MOVING BACK SOUTH
AND WOULD APPEAR CLEARING IN SE ND WILL NOT LAST LONG AND MOST
AREAS TO REMAIN RATHER CLOUDY OVERNIGHT. EXCEPTION IS FAR
NORTHEASTER FCST AREA WHERE CLEARING OVER ERN MB/NW ONT NORTH OF
FLAG ISLAND MAY DROP SOUTH BY 12Z. KEPT THAT AREA STILL NR -10F
FOR LOWS TONIGHT OTHERWISE UPPED LOWS MOST AREAS TO STAY GENERALLY
5 BELOW TO 5 ABOVE. WIND CHILLS SHOULD NOT GET INTO ADV CRITERIA.
PREV DISCUSSION... /ISSUED 707 PM CST SAT FEB 2 2013/
DISCUSSION...
SFC LOW AT 0030Z JUST PAST WATERTOWN SD. MAIN WIND BELT HAS BEEN
FROM MINOT-WILLISTON THROUGH BISMARCK TO ABERDEEN TO WATERTOWN AS
MOST AREAS EXPERIENCED WINDS IN THE 40-50 MPH FOR A TIME. THE
STRONGER NORTHWEST WINDS HAVE BEEN EVER SO SLOWLY EDGING EASTWARD
BUT AT THE SAME TIME THE MAIN PRESSURE RISE IS MOVING SOUTHEAST
AWAY FROM OUR REGION. THUS EXPECT ONLY REAL ISSUE WITH WIND SPEEDS
30KTS OR SO WILL BE VALLEY CITY-LISBON-GWINNER AREAS WHILE THE
REST OF ERN ND TO SEE SEE WINDS IN THE 10 TO 20 KT RANGE. THUS
DROPPED THE WINTER WX ADV FOR DVL REGION AND FOR WILKIN CO MN AS
MAIN WINDS TO STAY WEST OF THE RED RIVER. DID CONTINUE MENTION OF
-SN AND FLURRIES THRU MIDNIGHT IN MANY AREAS. SOME CLEARING MOVING
INTO CNTRL ND THIS EVE CLOSER TO MAIN SFC HIGH BUT ALSO QUITE A
BIT OF CLOUDS UPSTREAM IN MANITOBA SO UNSURE HOW MUCH CLEARING
WILL GET EAST INTO ERN ND BEFORE CLOUDS MAY DROP BACK IN. NW MN
ESP LOOKS IFFY FOR MUCH CLEARING. WITH PERHAPS MORE CLOUDINESS
OVERNIGHT DID RAISE LOW TEMPS A BIT IN NE ND/NW MN AND WITH PROG
WINDS WIND CHILLS TO STAY IN THE -20 TO -25 RANGE AND OUT OF
ADVISORY RANGE.
AVIATION...
EXPECT A WIND SHIFT ENTER THE RED RIVER VALLEY IN THE 01Z-03Z
PERIOD MOSTLY IN THE 10 TO 20 KT RANGE... LIGHT SNOW AND LOW END
VFR AND PATCHY MVFR CIGS TO PERSIST TIL 06Z AND THEN BE MOSTLY VFR
AREA WIDE.
PREV DISCUSSION... /ISSUED 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.
&&
.FGF WATCHES/WARNINGS/ADVISORIES...
ND...NONE.
MN...NONE.
&&
$$
RIDDLE
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
1120 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...THROUGH 06Z MONDAY
1120 PM CST SAT FEB 2 2013
THE SURFACE LOW HAS PROGRESSED SOUTHEAST TO NEAR THE
IOWA/MINNESOTA BORDER BETWEEN KAEL AND KFRM. THE BACK EDGE OF THE
MAIN SNOW BAND IS NOW APPROACHING THE MISSISSIPPI RIVER AND WILL
MOVE EAST OF KLSE SHORTLY AFTER 06Z. STILL SOME ADDITIONAL LIGHT
SNOW UPSTREAM TOWARD THE TWIN CITIES THAT COULD PRODUCE SOME
OCCASIONAL MVFR VISIBILITIES THROUGH THE MIDDLE OF THE NIGHT.
OBSERVATIONS OVER MANITOBA AND SASKATCHEWAN INDICATE THE PRESENCE
OF SOME DRY AIR WHERE SKIES HAVE CLEARED OUT. THIS DRY AIR WILL
QUICKLY MOVE OVER THE AREA SUNDAY MORNING WITH A PERIOD OF ONLY
SOME SCATTERED CLOUDS INTO THE AFTERNOON BEFORE THE NEXT ROUND OF
CLOUDS ARRIVE AHEAD OF THE NEXT SHORT WAVE TROUGH. THIS NEXT SHORT
WAVE TROUGH WILL HAVE BETTER FORCING THAN THIS EVENINGS SYSTEM
WITH UP TO 20 PVU/S OF VORTICITY ADVECTION IN THE 500-300 MB LAYER
SUNDAY EVENING. THE SURFACE LOW IS EXPECTED TRACK SOUTHEAST ACROSS
CENTRAL SOUTH DAKOTA INTO SOUTHEAST IOWA SUNDAY NIGHT WITH THE
WARM FRONT JUST TO SOUTH OF THE AREA. WEAK TO MODERATE
FRONTOGENESIS WILL OCCUR NORTH OF THE WARM FRONT IN THE 850-500 MB
LAYER...WHICH SHOULD BE RIGHT OVER THE AREA. ISENTROPIC UP GLIDE
OF 3 TO 5 UBAR/S WILL ALSO OCCUR NORTH OF THE WARM FRONT AND THE
COMBINATION OF THE LOW LEVEL FORCING AND DYNAMIC FORCING FROM THE
WAVE IS EXPECTED TO PRODUCE YET ANOTHER BAND OF LIGHT SNOW. LOOK
FOR THIS START MOVING IN AROUND 00Z WITH MVFR CEILINGS AND
VISIBILITIES WITH THE VISIBILITY GOING DOWN TO IFR WITHIN AN HOUR
OR TWO OF THE SNOW BEGINNING. IMPROVEMENTS WILL NOT OCCUR UNTIL
AFTER 06Z MONDAY.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
230 PM CST SAT FEB 2 2013
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
SHORT TERM...RIECK
LONG TERM....RIECK
AVIATION...04
AS HAS BEEN REPEATEDLY MENTIONED IN RECENT FORECAST DISCUSSIONS...
THE UPPER LEVEL PATTERN WILL SEE LITTLE PROGRESSION INTO EARLY NEXT
WEEK AND YET ANOTHER CLIPPER IS EXPECTED TO DROP THROUGH THE NWLY
FLOW ALOFT. THE MODELS REMAIN CONSISTENT ON THIS SYSTEM TAKING A
MORE NORTHERLY TRACK THROUGH WISCONSIN. SO...WHILE IT IS
ANTICIPATED THAT THE NRN IL/NWRN IN SHOULD SEE SOME ADDITIONAL
ACCUMULATING SNOW ON TUESDAY...THE HEAVIEST AMOUNTS SHOULD BE NORTH
OF THE WISCONSIN BORDER...WITH PERHAPS...AN INCH OR TWO OVER THE FAR
NRN PORTIONS OF THE CWA.
FOR THE LONGER TERM FORECAST PERIOD...THE UPPER LEVEL PATTERN IS
FINALLY EXPECTED TO BECOME MORE PROGRESSIVE. AS THE UPPER RIDGE
SHIFTS FROM THE WEST COAST TO ACROSS THE ROCKIES AND OUT OVER THE
PLAINS...TEMPERATURES WILL BEGIN AN INCREASING TREND...THROUGH THERE
WILL STILL BE PERIODIC CHANCES FOR PCPN FROM WEDNESDAY THROUGH
SATURDAY...BUT THIS WILL BE DUE TO PACIFIC SYSTEMS...RATHER THAN
ARCTIC-SOURCED SYSTEMS. SO...WITH THE INCREASING TEMPERATURES...
THERE WILL ALSO BE CHANCES FOR RAIN. ALSO...THE INCREASING
TEMPERATURES WILL INCREASE THE POTENTIAL FOR ICE-BREAKUP JAMS ON
AREA RIVERS AND STREAMS AS THE RECENT COLD WEATHER HAS ALLOWED THE
RIVERS AND STREAMS TO FREEZE OVER.
KREIN
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 14Z...
* SNOW THIS MORNING.
* SMALL POTENTIAL FOR A PERIOD OF IFR CIGS IN THE 500 TO 1000 FT
RANGE AFTER 14 UTC THIS MORNING.
* W/NW WINDS WILL PERSIST ARND 5 TO 10 KT...THEN GUSTS DEVELOP
MIDDAY UP TO 20 KT. WINDS TURN SW/S OVERNIGHT.
* SNOW RETURNS TONIGHT...POTENTIALLY MODERATE TO HEAVY AT TIMES...WITH
LIMITED VSBYS AND LOWERING CIGS AFT 04Z.
BEACHLER/KB
//DISCUSSION...UPDATED 14Z...
MAIN CONCERN HAS NOW FOCUSED AWAY FROM THE IFR CIGS...AS IT
APPEARS THEY WILL STAY AWAY FROM THE EASTERN TERMINALS.
HOWEVER...SNOW SHOWERS HAVE BECOME RATHER ROBUST ACROSS PORTIONS
OF THE AREA OVER THE PAST HOUR. THIS APPEARS TO BE A RESULT OF
CONVERGENCE ALONG THE FRONTAL BOUNDARY TO THE WEST. MODEL BUFFER
SOUNDINGS INDICATE VERY DEEP SATURATED THERMAL PROFILES WITHIN THE
FAVORABLE DENDRITIC GROWTH ZONE. WITH THIS IN MIND...EXPECT THE VIS
TO DROP DOWN AROUND OR JUST UNDER 2 MILES IN THE HEAVIER SNOW
SHOWERS. THE BEST CHANCES APPEAR TO BE SHIFTING FROM THE WESTERN
SUBURBS AND OVER THE EASTERN TERMINALS THROUGH THE MORNING. THE
BEST TIMING APPEARS TO BE BETWEEN 14 AND 16 UTC...BEFORE THE SNOW
SHOWERS BEGIN TO ABATE.
KB
//DISCUSSION...UPDATED 12Z...
ANOTHER CLIPPER SYSTEM EARLY THIS MORNING WAS BRINGING LIGHT SNOW
TO NORTHERN IL/NORTHWEST IN AIRFIELDS. WINDS HAVE REMAINED VERY
LIGHT FROM THE WEST ARND 5 TO 10 KT...HOWEVER WINDS WILL BEGIN TO
SHIFT NW LATER THIS MORNING. THE GRADIENT WILL INCREASE WITH
OCCASIONAL GUSTS TO 20 KT BY MIDDAY. CIGS SHOULD SLOWLY LOWER AS
MOISTURE CONTINUES TO PUSH EAST TOWARDS ORD/MDW AIRFIELDS THIS
MORNING...PUSHING CIGS DOWN TO MVFR CONDS. UPSTREAM CIGS ARE MUCH
LOWER...HOWEVER NOT ANTICIPATING THAT THOSE LOW CIGS WILL ARRIVE
AT ORD. THEN FLURRIES WILL LINGER LATER THIS MORNING...BEFORE
ENDING AROUND MIDDAY.
FOR TONIGHT WINDS WILL SLOWLY TURN WESTERLY...AS YET ANOTHER
CLIPPER SYSTEM APPROACHES FROM THE NORTHWEST. THIS NEXT WAVE
APPEARS TO BE SLIGHTLY STRONGER...AND IS EXPECTED TO APPROACH KRFD
AROUND 2-4Z WITH THE STEADIER SNOW BEGINNING ABOUT 2-3 HOURS AFTER
THE ONSET. THEN THIS LINE OF SNOW WILL APPROACH ORD/MDW CLOSER TO
04-06Z. CIGS WILL STEADILY LOWER AGAIN IN ADVANCE OF THIS
WAVE...LOWERING TO 2KFT AGL IN MANY LOCATIONS. AS STEADIER SNOW
PUSHES OVERHEAD...VSBYS WILL QUICKLY LOWER AS WELL TO NEAR 1SM BY
07Z. LOW CIGS/VSBYS WILL THEN LINGER THRU DAYBREAK MON. AS THE
CLIPPER APPROACHES THE AREA...WINDS WILL THEN TURN SOUTHERLY TO
SOUTHEASTERLY 12-14Z MON.
BEACHLER
//ORD AND MDW CONFIDENCE...UPDATED 14Z...
* LOW CONFIDENCE ON IFR CIGS THIS MORNING.
* HIGH CONFIDENCE IN SNOW SHOWERS TRANSITIONING TO FLURRIES LATER
THIS MORNING.
* HIGH CONFIDENCE IN LIGHT SNOW AND LOWERING VSBYS/CIGS TONIGHT.
* MEDIUM/HIGH CONFIDENCE IN TIMING OF SNOW AFT 04Z MON.
BEACHLER/KB
//OUTLOOK FOR ORD/MDW FOR 00Z TUESDAY-12Z SUNDAY...UPDATED 12Z...
MONDAY NIGHT...MVFR CIGS TRENDING VFR.
TUESDAY...MVFR WITH LIGHT SNOW.
WEDNESDAY...VFR.
THURSDAY...PSBL MVFR WITH LIGHT RAIN/SNOW.
FRIDAY THROUGH SATURDAY...VFR.
BEACHLER
&&
.MARINE...
310 AM CST
WEAK RIDGE OF HIGH PRESSURE OVERHEAD HAS ALLOWED WINDS TO DIMINISH
CONSIDERABLY EARLY THIS MORNING...HOWEVER THIS RIDGE WAS STEADILY
SLIDING EAST AS A WEAKENING TROUGH OF LOW PRESSURE WAS PUSHING
EAST INTO NORTHERN ILLINOIS. AS THIS TROUGH APPROACHES THE
AREA...THE GRADIENT WILL QUICKLY TIGHTEN. THIS WILL ALLOW WEST
WINDS TO INCREASE TO 20 TO 25 KT BY MIDDAY THEN CONTINUE TO
INCREASE TO 30 KT AS THEY TURN NORTHWEST. A FEW GALE FORCE GUSTS
MAY OCCUR...HOWEVER FEEL THE FREQUENCY OF GALES WILL BE VERY LOW.
IN THE NEARSHORE WINDS SHOULD TOUCH SMALL CRAFT CRITERIA...HOWEVER
IT APPEARS TO BE BORDERLINE. WILL CONTINUE TO HAVE THE SMALL CRAFT
ADVISORY GOING. ICE COVERAGE IN THE NEARSHORE WATERS HAS INCREASED
OVER THE PAST FEW DAYS...SO THE GREATEST CONCERN FOR SMALL CRAFT
WOULD BE WINDS RATHER THAN THE WAVES. WITH THE PROLONGED NORTHWEST
FETCH TO THE WINDS...SMALL CRAFT CONDITIONS WILL CONTINUE A LITTLE
LONGER FOR THE INDIANA NEARSHORE WATERS.
A STRONGER LOW APPROACHES FROM THE NORTHWEST TUESDAY AND STEADILY
WEAKENS AS IT SLIDES ACROSS THE LAKE. SOUTHWEST WINDS INCREASE TO 20
KT TUESDAY MORNING...THEN BECOMING NORTHWEST TUESDAY NIGHT.
BEACHLER
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...SMALL CRAFT ADVISORY...NEARSHORE GARY TO MICHIGAN CITY IN UNTIL 4 AM MONDAY.
SMALL CRAFT ADVISORY...NEARSHORE WINTHROP HARBOR TO GARY IN UNTIL 6 PM
SUNDAY.
&&
$$
AREA FORECAST DISCUSSION
NWS PADUCAH KY
418 AM CST SUN FEB 3 2013
.UPDATE...
ISSUED AT 418 AM CST SUN FEB 3 2013
WILL GET RID OF THE WINTER WEATHER ADVISORY SOON. UPDATE TO THE
AVIATION SECTION AS WELL.
&&
.SHORT TERM...(TODAY THROUGH TUESDAY NIGHT)
ISSUED AT 250 AM CST SUN FEB 3 2013
FAST MOVING CLIPPER LIKE SYSTEM RESULTING IN SURPRISE 1-2 INCH
SNOW AMOUNTS ACROSS NORTHERN PORTIONS OF THE AREA...IN SOME BANDS.
RADAR MOSAIC SHOWED THE ACTIVITY ENDING RAPIDLY FROM NORTHWEST TO
SOUTHEAST ACROSS SOUTHERN ILLINOIS...SO MAY END THE ADVISORY MUCH
SOONER THAN 6 AM IN THOSE AREAS. SNOW SHOULD ESSENTIALLY BE GONE
BY DAYBREAK AS IT DEPARTS THE PENNYRILE REGION OF WEST KY...SO A
DRY QUIET WX DAY IN STORE FOR THE AREA...WITH DRY WEATHER
CONTINUING TONIGHT.
SYSTEM STILL FORECAST TO MOVE ACROSS THE AREA MONDAY. WARMER
CONDITIONS...SO RAIN IS FORECAST. MAINTAINED OUR LIKELY POPS FOR
NOW. SYSTEM WILL DEPART EARLY MONDAY EVENING WITH DRY WEATHER
FORECAST TO RETURN FOR THE REST OF MONDAY NIGHT ON THROUGH
TUESDAY NIGHT.
USED A BLEND OF GFS/NAM AND ECS MOS FOR TEMPS...WITH A MIX OF
2M MODEL TEMPS AND WEIGHTED OUTPUT.
.LONG TERM...(WEDNESDAY THROUGH SATURDAY)
ISSUED AT 250 AM CST SUN FEB 3 2013
QUASI ZONAL UPPER LEVEL FLOW PATTERN DURING THE MIDDLE OF THE WEEK
WILL TRANSITION TO A SOUTHWEST FLOW PATTERN BY SATURDAY AS STRONG
UPPER LEVEL TROUGHING DEVELOPS OVER THE WESTERN STATES.
AS FAR AS THE DAILY DETAILS...
WEAK SURFACE HIGH PRESSURE WILL PASS EAST ACROSS THE MID MISSISSIPPI
VALLEY ON WEDNESDAY. MAINLY CLEAR SKIES ARE EXPECTED...WITH LIGHT
WINDS AND NEAR NORMAL TEMPERATURES.
A 500 MB SHORTWAVE TROUGH EMBEDDED IN THE ZONAL FLOW WILL MOVE
QUICKLY EAST ACROSS THE GREAT LAKES ON THURSDAY AND THURSDAY NIGHT.
THE GFS CONTINUES TO DEPICT A RATHER LOW AMPLITUDE TROUGH OVER THE
GREAT LAKES. THE 00Z ECMWF IS MUCH MORE AMPLIFIED...DEPICTING THE
TROUGH WELL DOWN INTO THE LOWER OHIO VALLEY. FORECAST WILL CONTINUE
TO LEAN MORE TOWARD THE WEAKER GFS...WITH ONLY CHANCE POPS IN THE
THURSDAY AND THURSDAY NIGHT TIME FRAME. WARM ADVECTION IN ADVANCE OF
THE APPROACHING SURFACE COLD FRONT WILL RAISE TEMPS ABOVE SEASONAL
NORMS. PRECIP TYPE SHOULD BE RAIN THURSDAY/THURSDAY NIGHT.
SHORTWAVE RIDGING WILL INCREASE ACROSS THE MISSISSIPPI VALLEY ON
FRIDAY AS THE WESTERN TROUGH BEGINS TO TAKE SHAPE. DRY CONDITIONS
ARE EXPECTED ON FRIDAY AND FRIDAY NIGHT.
DEEP LAYER SOUTHWEST FLOW WILL INCREASE ON SATURDAY AHEAD OF A
RATHER IMPRESSIVE WESTERN TROUGH. MOISTURE WILL BE ON THE
INCREASE...WITH PRECIP SPREADING NORTHEAST FROM THE SOUTHERN PLAINS.
MODELS DIFFER ON TIMING OF THE PRECIP ARRIVAL. WILL KEEP POPS ONLY
IN THE 20 TO 30 PERCENT RANGE FOR SATURDAY...SINCE MOST OF THE
PRECIP WILL LIKELY HOLD OFF UNTIL LATER IN THE WEEKEND. SOME THUNDER
CANNOT BE RULED OUT AS A SOUTHWEST LOW LEVEL JET DEVELOPS...BRINGING
HIGHER THETA/E AIR NORTHEAST INTO THE MID MISSISSIPPI VALLEY.
TEMPS WILL BE UNSEASONABLY MILD.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z MONDAY MORNING)
ISSUED AT 418 AM CST SUN FEB 3 2013
WILL CONTINUE WITH SOME STRATO-CU THROUGH THE DAY BASED ON UPSTREAM
OBS AND RUC DATA. THAT SHOULD CLEAR OUT THIS EVENING AND OVERNIGHT.
HOWEVER...IN TURN WE MAY BE LOOKING AS SOME MID OR HIGH CLOUDS. NW
WINDS TODAY WILL BECOME LIGHT SE TONIGHT.
&&
.PAH WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
MO...NONE.
IN...NONE.
KY...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS GRAY ME
848 AM EST SUN FEB 3 2013
.SYNOPSIS...
LOW PRESSURE WILL DEVELOP IN THE ATLANTIC WELL EAST OF THE REGION
TODAY AND MOVE NORTHEAST. A COLD...BRISK FLOW WILL BEGIN ON
MONDAY...FOLLOWED BY THE PASSAGE OF A WEAK RIDGE OF HIGH PRESSURE
THROUGH MIDWEEK. LOW PRESSURE WILL APPROACH THE MID ATLANTIC
REGION THURSDAY AND HEAD NORTHEAST.
&&
.NEAR TERM /UNTIL 7 PM THIS EVENING/...
830 AM UPDATE...SKIES ARE SUNNY IN MANY AREAS AND PARTLY SUNNY IN
ALONG THE COAST WITH SOME HIGH THIN CLOUDS OVERHEAD. THE MORE
OPAQUE CLOUDS ARE NOW JUST OFF THE COAST. TEMPS ACROSS INTERIOR
AND MOUNTAINS ARE A BIT COLDER THAN ORIGINAL FORECAST DUE TO
MOSTLY CLEAR SKIES ACROSS THE REGION. HAVE ADJUST SKY...TEMP AND
DEW POINT FCST TO REFLECT CURRENT CONDITIONS. CLOUDS WILL BE ON
THE INCREASE FROM SOUTH TO NORTH DURING THE DAY AS OCEAN LOW
DEVELOPS AND STARTS MOVING NORTHEAST.
UPDATE...BROUGHT LOW TEMPS UP ALONG THE COAST AND INTERIOR...WHERE
CIRRUS SHIELD IS KEEPING ANY RADIATIONAL COOLING AT BAY. HAVE ALSO
BLENDED IN THE LATEST HRRR POP TO ACCOUNT FOR CURRENT
OBSERVATIONAL TRENDS IN SN ALONG THE COAST AND OVER THE WATERS.
LATEST DATA FROM GYX 88D INDICATES SW MOVING ECHOES OVER THE
WATERS...ON A TRAJECTORY FOR COASTAL YORK AND ROCKINGHAM COUNTIES.
THIS IS ON THE LEADING EDGE OF NELY SURGE WORKING FROM DOWNEAST.
WHETHER OR NOT THIS MAINTAINS ITSELF LONG ENOUGH TO WORK INLAND IS
STILL IN QUESTION...BUT HAVE MADE SURE THAT AT LEAST CHC POP IS
THERE FOR SERN NH AND SWRN ME THIS MORNING. TIME OF ARRIVAL TOOL
PLACES THE LEADING EDGE AT KPSM AROUND 16 OR 17Z...AND THIS IS
REFLECTED IN POP TRENDS.
PREVIOUS DISCUSSION...WEAK LEAD S/WV TROF LIFTING THRU THE
LARGER ERN L/WV TROF IS SUPPORTING A WEAK LOW PRES SKIRTING THRU
THE GULF OF MAINE. CLOUD SHIELD IS ROUGHLY BISECTING THE
CWFA...WITH VERY LIGHT SN OCCURRING ACROSS SERN NH AND EXTREME
SWRN ME. GENERALLY HAVE SCHC TO CHC POP FOR COASTAL ZONES
TODAY...AS OVERALL SYSTEM ORGANIZATION WILL BE LACKING.
ONE FEATURE OF NOTE IS THE SFC TROF THAT EXTENDS BACK TO THE NW OF
THE WEAK LOW PRES CENTER. WINDS ARE NW AT MISM1...KLEW...AND KPWM.
WHILE AT KSFM AND IOSN3 WINDS ARE WSW. WITHIN THIS TROF...MORE
CONVECTIVE SHSN HAVE BEEN OCCURRING AND PROPAGATING WITH THE LLVL
FLOW. SOME BRIEFLY HEAVIER SNOWFALL RATES ARE PSBL IN ANY OF THESE
SHSN. MESOSCALE MODEL GUIDANCE WAS HANDLING THIS FEATURE VERY WELL
THIS MORNING...WITH THE HRRR AND LOCAL WRF FEATURING HIGH POP
WITHIN THE TROF AXIS. HAVE STARTED POP GRIDS HERE AND BLENDED
TOWARDS THIS AFTN. AS STRONGER S/WV TROF OFF THE MIDATLANTIC
REIGNITES SFC CYCLOGENESIS S OF NEW ENGLAND TODAY...WINDS WILL
BEGIN TO BECOME MORE NLY AND NELY ACROSS THE CWFA AND WATERS.
MESOSCALE MODELS FAVOR SHSN CONTINUING WITH THE WEAK SFC TROF AS
IT PUSHES BACK TO THE SW TODAY. THIS COULD KEEP THE NH SEACOAST
AND EXTREME SWRN ME IN THE SHSN A LITTLE LONGER THAN THE REST OF
THE COAST. HAVE LINGERED THE CHC POP IN THIS AREA INTO THE AFTN TO
ACCOUNT FOR THIS POSSIBILITY.
OTHERWISE...UPSLOPE SHSN GRADUALLY WIND DOWN THIS MORNING. A FEW
POCKETS WHERE CLOUDS SCATTER OUT WILL RADIATE WELL...AND LOWS WILL
APPROACH SUB-ZERO. THIS AFTN...CIRRUS SHIELD WILL PREVENT IDEAL
DIURNAL HEATING...AND HIGHS IN THE 20S TO NEAR 30 ARE A BLEND OF
THE MAV AND LOCAL WRF GUIDANCE.
&&
.SHORT TERM /7 PM THIS EVENING THROUGH 6 PM MONDAY/...
UPR TROF CROSSES THE AREA OVERNIGHT INTO MON. WILL SEE CLOUDS
INCREASE AHEAD OF IT...ALONG WITH MORE WIDESPREAD
SHSN. THIS IS ESPECIALLY TRUE IN THE MTNS...WHERE DEVELOPING WLY
FLOW WILL SET OFF ANOTHER ROUND OF UPSLOPE SN. THE PROGRESSIVE
FLOW WILL KICK SFC LOW PRES WELL OUT TO SEA THOUGH...AND HAVE CUT
BACK ON AREA OF CHC POP FOR A LARGE PORTION OF THE CWFA. GREATEST
THREAT FOR STEADIER PCPN WILL BE ON THE MIDCOAST...WHERE LOW PRES
CUTTING WWD ACROSS THE BAROCLINIC ZONE AS IT RAPIDLY DEEPENS MAY
PASS CLOSER ENOUGH TO DOWNEAST MAINE TO BRUSH AREAS AROUND
PENOBSCOT BAY WITH -SN.
WITH THE PASSAGE OF THE UPR TROF...STRONG CAA KICKS IN EARLY MON.
DEEP MIXING LAYER WILL SUPPORT STRONGER WIND GUSTS TO TRANSLATE TO
THE SFC. ATTM GUSTS AROUND 30 KTS LOOK LIKELY...WITH A LOW
PROBABILITY FOR HIGHER GUSTS DEPENDING ON EXACT STRENGTH AND
TRACK OF LOW PRES. THE CLOSER TO THE CWFA...THE TIGHTER THE PRES
GRADIENT WILL BE.
&&
.LONG TERM /MONDAY NIGHT THROUGH SATURDAY/...
A BRISK NORTHWEST FLOW WILL ALLOW FOR MORE ARCTIC AIR TO ENTER THE
REGION MONDAY NIGHT BEHIND A DEPARTING FULL FLEDGED STORM OVER THE
CANADIAN MARITIMES. WITH THE EXCEPTION OF A FEW FLURRIES FROM A
SYSTEM WELL OFF THE EAST COAST ON WEDNESDAY...EXPECT DRY AND
MAINLY CLEAR CONDITIONS. MORE MOISTURE AND CLOUDINESS WILL HANG UP
IN THE MOUNTAINS HOWEVER DURING THIS PERIOD.
ALL BETS ARE OFF LATE IN THE WEEK AS THERE ARE GREAT DISCREPANCIES
WITH THE 00Z MODEL RUN. THE GGEM AND GFS BRING A SYSTEM TO OUR
WEST THURSDAY NIGHT INTO FRIDAY. THE LATEST EURO RUN IS MUCH MORE
WELL DEFINED WITH A STRONG EAST COAST LOW OVER THE DELMARVA REGION
BY 12Z FRIDAY. THIS SYSTEM SLOWLY MOVES NORTHEAST...WITH A BLOCKING
HIGH TO THE NORTH OF MAINE DURING THIS PERIOD. FOR THE TIME
BEING...WE HAVE CHANCE POPS FOR THIS SYSTEM FOR THE DAY 6 PERIOD.
INTERESTED TO SEE IF THE 12Z RUNS HOLD ONTO THIS SLOW MOVING
FEATURE. ASTRONOMICAL TIDES WILL BE RELATIVELY HIGH DURING THIS
PERIOD AS WELL.
&&
.AVIATION /14Z SUNDAY THROUGH THURSDAY/...
SHORT TERM...AREAS OF MVFR WITH LOCAL IFR CONDS THIS MORNING ALONG
COAST. DIVIDING LINE WILL BE BETWEEN KCON AND KPSM...RUNNING ENE
THRU KAUG AND KRKD. N OF THIS LINE EXPECT NO PCPN...EXCEPT FOR
KHIE WHERE UPSLOPE SHSN WILL GRADUALLY WIND DOWN THIS MORNING.
BECOMING VFR THIS AFTN
LATE SUN THERE IS A LOW PROBABILITY OF MVFR OR IFR SN TO WORK INTO
KRKD IN ASSOCIATION WITH AN OCEAN LOW PRES. MORE LIKELY IS THAT
BEHIND LOW PRES ON MON STRONG WLY WINDS DEVELOP...WITH GUSTS AOA
25 KT. UPSLOPE SHSN WILL BEGIN AGAIN FOR KHIE AND KLEB LATE SUN
THRU MON.
LONG TERM...CONDITIONS MAY DETERIORATE ONCE AGAIN BY FRIDAY AS LOW
PRESSURE APPROACHES.
&&
.MARINE...
SHORT TERM...WINDS AND SEAS REMAIN BELOW SCA THRESHOLDS ATTM.
DEVELOPING LOW PRES S OF NEW ENGLAND TODAY WILL CREATE NE FLOW ON
THE WATERS THRU THIS AFTN. COULD SEE WINDS APPROACH SCA GUSTS
LATER TODAY AS A RESULT. WITH THE PASSAGE OF A COLD FNT
MON...STRONG WLY FLOW WILL DEVELOP DURING THE MORNING AND INTO THE
AFTN. WINDS COULD GUST ABOVE GALE FORCE INTO TUE.
LONG TERM...GALES ARE POSSIBLE ONCE AGAIN ON FRIDAY.
&&
.GYX WATCHES/WARNINGS/ADVISORIES...
ME...NONE.
NH...NONE.
MARINE...GALE WATCH FROM MONDAY MORNING THROUGH LATE MONDAY NIGHT FOR
ANZ150>154.
&&
$$
SYNOPSIS...
NEAR TERM...JENSENIUS
AREA FORECAST DISCUSSION...UPDATED
NWS GRAY ME
607 AM EST SUN FEB 3 2013
.SYNOPSIS...
LOW PRESSURE WILL DEVELOP IN THE ATLANTIC WELL EAST OF THE REGION
TODAY AND MOVE NORTHEAST. A COLD...BRISK FLOW WILL BEGIN ON
MONDAY...FOLLOWED BY THE PASSAGE OF A WEAK RIDGE OF HIGH PRESSURE
THROUGH MIDWEEK. LOW PRESSURE WILL APPROACH THE MID ATLANTIC
REGION THURSDAY AND HEAD NORTHEAST.
&&
.NEAR TERM /THROUGH TONIGHT/...
UPDATE...BROUGHT LOW TEMPS UP ALONG THE COAST AND INTERIOR...WHERE
CIRRUS SHIELD IS KEEPING ANY RADIATIONAL COOLING AT BAY. HAVE ALSO
BLENDED IN THE LATEST HRRR POP TO ACCOUNT FOR CURRENT
OBSERVATIONAL TRENDS IN SN ALONG THE COAST AND OVER THE WATERS.
LATEST DATA FROM GYX 88D INDICATES SW MOVING ECHOES OVER THE
WATERS...ON A TRAJECTORY FOR COASTAL YORK AND ROCKINGHAM COUNTIES.
THIS IS ON THE LEADING EDGE OF NELY SURGE WORKING FROM DOWNEAST.
WHETHER OR NOT THIS MAINTAINS ITSELF LONG ENOUGH TO WORK INLAND IS
STILL IN QUESTION...BUT HAVE MADE SURE THAT AT LEAST CHC POP IS
THERE FOR SERN NH AND SWRN ME THIS MORNING. TIME OF ARRIVAL TOOL
PLACES THE LEADING EDGE AT KPSM AROUND 16 OR 17Z...AND THIS IS
REFLECTED IN POP TRENDS.
PREVIOUS DISCUSSION...WEAK LEAD S/WV TROF LIFTING THRU THE
LARGER ERN L/WV TROF IS SUPPORTING A WEAK LOW PRES SKIRTING THRU
THE GULF OF MAINE. CLOUD SHIELD IS ROUGHLY BISECTING THE
CWFA...WITH VERY LIGHT SN OCCURRING ACROSS SERN NH AND EXTREME
SWRN ME. GENERALLY HAVE SCHC TO CHC POP FOR COASTAL ZONES
TODAY...AS OVERALL SYSTEM ORGANIZATION WILL BE LACKING.
ONE FEATURE OF NOTE IS THE SFC TROF THAT EXTENDS BACK TO THE NW OF
THE WEAK LOW PRES CENTER. WINDS ARE NW AT MISM1...KLEW...AND KPWM.
WHILE AT KSFM AND IOSN3 WINDS ARE WSW. WITHIN THIS TROF...MORE
CONVECTIVE SHSN HAVE BEEN OCCURRING AND PROPAGATING WITH THE LLVL
FLOW. SOME BRIEFLY HEAVIER SNOWFALL RATES ARE PSBL IN ANY OF THESE
SHSN. MESOSCALE MODEL GUIDANCE WAS HANDLING THIS FEATURE VERY WELL
THIS MORNING...WITH THE HRRR AND LOCAL WRF FEATURING HIGH POP
WITHIN THE TROF AXIS. HAVE STARTED POP GRIDS HERE AND BLENDED
TOWARDS THIS AFTN. AS STRONGER S/WV TROF OFF THE MIDATLANTIC
REIGNITES SFC CYCLOGENESIS S OF NEW ENGLAND TODAY...WINDS WILL
BEGIN TO BECOME MORE NLY AND NELY ACROSS THE CWFA AND WATERS.
MESOSCALE MODELS FAVOR SHSN CONTINUING WITH THE WEAK SFC TROF AS
IT PUSHES BACK TO THE SW TODAY. THIS COULD KEEP THE NH SEACOAST
AND EXTREME SWRN ME IN THE SHSN A LITTLE LONGER THAN THE REST OF
THE COAST. HAVE LINGERED THE CHC POP IN THIS AREA INTO THE AFTN TO
ACCOUNT FOR THIS POSSIBILITY.
OTHERWISE...UPSLOPE SHSN GRADUALLY WIND DOWN THIS MORNING. A FEW
POCKETS WHERE CLOUDS SCATTER OUT WILL RADIATE WELL...AND LOWS WILL
APPROACH SUB-ZERO. THIS AFTN...CIRRUS SHIELD WILL PREVENT IDEAL
DIURNAL HEATING...AND HIGHS IN THE 20S TO NEAR 30 ARE A BLEND OF
THE MAV AND LOCAL WRF GUIDANCE.
&&
.SHORT TERM /MONDAY/...
UPR TROF CROSSES THE AREA OVERNIGHT INTO MON. WILL SEE CLOUDS
INCREASE AHEAD OF IT...ALONG WITH MORE WIDESPREAD
SHSN. THIS IS ESPECIALLY TRUE IN THE MTNS...WHERE DEVELOPING WLY
FLOW WILL SET OFF ANOTHER ROUND OF UPSLOPE SN. THE PROGRESSIVE
FLOW WILL KICK SFC LOW PRES WELL OUT TO SEA THOUGH...AND HAVE CUT
BACK ON AREA OF CHC POP FOR A LARGE PORTION OF THE CWFA. GREATEST
THREAT FOR STEADIER PCPN WILL BE ON THE MIDCOAST...WHERE LOW PRES
CUTTING WWD ACROSS THE BAROCLINIC ZONE AS IT RAPIDLY DEEPENS MAY
PASS CLOSER ENOUGH TO DOWNEAST MAINE TO BRUSH AREAS AROUND
PENOBSCOT BAY WITH -SN.
WITH THE PASSAGE OF THE UPR TROF...STRONG CAA KICKS IN EARLY MON.
DEEP MIXING LAYER WILL SUPPORT STRONGER WIND GUSTS TO TRANSLATE TO
THE SFC. ATTM GUSTS AROUND 30 KTS LOOK LIKELY...WITH A LOW
PROBABILITY FOR HIGHER GUSTS DEPENDING ON EXACT STRENGTH AND
TRACK OF LOW PRES. THE CLOSER TO THE CWFA...THE TIGHTER THE PRES
GRADIENT WILL BE.
&&
.LONG TERM /MONDAY NIGHT THROUGH SATURDAY/...
A BRISK NORTHWEST FLOW WILL ALLOW FOR MORE ARCTIC AIR TO ENTER THE
REGION MONDAY NIGHT BEHIND A DEPARTING FULL FLEDGED STORM OVER THE
CANADIAN MARITIMES. WITH THE EXCEPTION OF A FEW FLURRIES FROM A
SYSTEM WELL OFF THE EAST COAST ON WEDNESDAY...EXPECT DRY AND
MAINLY CLEAR CONDITIONS. MORE MOISTURE AND CLOUDINESS WILL HANG UP
IN THE MOUNTAINS HOWEVER DURING THIS PERIOD.
ALL BETS ARE OFF LATE IN THE WEEK AS THERE ARE GREAT DISCREPANCIES
WITH THE 00Z MODEL RUN. THE GGEM AND GFS BRING A SYSTEM TO OUR
WEST THURSDAY NIGHT INTO FRIDAY. THE LATEST EURO RUN IS MUCH MORE
WELL DEFINED WITH A STRONG EAST COAST LOW OVER THE DELMARVA REGION
BY 12Z FRIDAY. THIS SYSTEM SLOWLY MOVES NORTHEAST...WITH A BLOCKING
HIGH TO THE NORTH OF MAINE DURING THIS PERIOD. FOR THE TIME
BEING...WE HAVE CHANCE POPS FOR THIS SYSTEM FOR THE DAY 6 PERIOD.
INTERESTED TO SEE IF THE 12Z RUNS HOLD ONTO THIS SLOW MOVING
FEATURE. ASTRONOMICAL TIDES WILL BE RELATIVELY HIGH DURING THIS
PERIOD AS WELL.
&&
.AVIATION /12Z SUNDAY THROUGH THURSDAY/...
SHORT TERM...AREAS OF MVFR WITH LOCAL IFR CONDS THIS MORNING ALONG
COAST. DIVIDING LINE WILL BE BETWEEN KCON AND KPSM...RUNNING ENE
THRU KAUG AND KRKD. N OF THIS LINE EXPECT NO PCPN...EXCEPT FOR
KHIE WHERE UPSLOPE SHSN WILL GRADUALLY WIND DOWN THIS MORNING.
BECOMING VFR THIS AFTN
LATE SUN THERE IS A LOW PROBABILITY OF MVFR OR IFR SN TO WORK INTO
KRKD IN ASSOCIATION WITH AN OCEAN LOW PRES. MORE LIKELY IS THAT
BEHIND LOW PRES ON MON STRONG WLY WINDS DEVELOP...WITH GUSTS AOA
25 KT. UPSLOPE SHSN WILL BEGIN AGAIN FOR KHIE AND KLEB LATE SUN
THRU MON.
LONG TERM...CONDITIONS MAY DETERIORATE ONCE AGAIN BY FRIDAY AS LOW
PRESSURE APPROACHES.
&&
.MARINE...
SHORT TERM...WINDS AND SEAS REMAIN BELOW SCA THRESHOLDS ATTM.
DEVELOPING LOW PRES S OF NEW ENGLAND TODAY WILL CREATE NE FLOW ON
THE WATERS THRU THIS AFTN. COULD SEE WINDS APPROACH SCA GUSTS
LATER TODAY AS A RESULT. WITH THE PASSAGE OF A COLD FNT
MON...STRONG WLY FLOW WILL DEVELOP DURING THE MORNING AND INTO THE
AFTN. WINDS COULD GUST ABOVE GALE FORCE INTO TUE.
LONG TERM...GALES ARE POSSIBLE ONCE AGAIN ON FRIDAY.
&&
.GYX WATCHES/WARNINGS/ADVISORIES...
ME...NONE.
NH...NONE.
MARINE...GALE WATCH FROM MONDAY MORNING THROUGH LATE MONDAY NIGHT FOR
ANZ150>154.
&&
$$
LEGRO/JC
AREA FORECAST DISCUSSION
NWS PITTSBURGH PA
959 AM EST SUN FEB 3 2013
.SYNOPSIS...
AN UNSETTLED PATTERN WITH PERIODS OF SNOW AND COLD TEMPERATURES
WILL CONTINUE THROUGH TUESDAY.
&&
.NEAR TERM /THROUGH TONIGHT/...
INFRARED SATELLITE IMAGE OF COLDER CLOUD TOPS ALIGN NICELY WITH
THE UPPER LEVEL SHORTWAVE DEPICTED BY THE RUC MODEL. AS OF
10AM...THIS FEATURE IS ACROSS WESTERN AND CENTRAL OHIO...AND IT
WILL SLOWLY MOVE EAST THROUGH THE DAY. WITH 10AM UPDATE...PRIMARY
CHANGE WAS TO BRING LIKELY POPS A LITTLE BIT FARTHER WEST INTO THE
NORTHERN WV PANHANDLE AND EASTERN OHIO...CONSIDERING RECENT RADAR
TRENDS. ALSO MADE SOME MINOR CHANGES TO TEMPERATURES (LOWERING
THEM SLIGHTLY) AND SNOWFALL (BUMPING SOME LOCATIONS UP A FEW
TENTHS OF AN INCH). PREVIOUS DISCUSSION FOLLOWS.
NEXT SHORTWAVE IN THE SERIES WILL CROSS THE OHIO VALLEY TODAY AND
EXIT TONIGHT. THIS CLIPPER TYPE SYSTEM IS MORE STRETCHED ALOFT
AND LESS ORGANIZED THAN SATURDAY SYSTEM...AND AROUND AN INCH OF
SNOW EXPECTED MOST LOCATIONS EXCEPT FOR THE RIDGES WHERE SOME
UPSLOPE ENHANCEMENT IN THE HIGHEST ELEVATIONS WILL ALLOW FOR 2-4
TODAY AND ANOTHER 1-2 TONIGHT IN PRESTON...TUCKER AND GARRETT
WHERE ADVISORY REMAINS IN PLACE. 1 TO 3 ADDITIONAL INCHES FOR THE
CHESTNUT AND LAURELS IN WESTMORELAND AND FAYETTE TODAY INTO THE
EVENING. TEMPERATURES WILL BE A TIGHT RANGE TODAY MAINLY IN THE
20S.
SURFACE RIDGE AXIS WILL BRING AN END TO THE SNOW OVERNIGHT AS IT
QUICKLY PASSES EAST OF THE APPALACHIANS. LOWS IN THE TEENS WITH A
FEW SINGLE DIGITS RIDGES. HOW QUICKLY WIND FIELDS WEAKEN WILL
DETERMINE HOW LOW WIND CHILL VALUES CAN GET. -10F OR COLDER
POSSIBLE ACROSS PRESTON...TUCKER AND GARRET AND MENTIONED IN
FORECAST BUT WILL HOLD OFF ON ADVISORY.
&&
.SHORT TERM /MONDAY THROUGH TUESDAY/...
MODELS NOW IN GENERAL AGREEMENT ON NEXT CLIPPER BEING BETTER
ORGANIZED WITH A WARM ADVECTION REGIME AHEAD OF IT SPREADING SNOW
INTO EASTERN OHIO BY MIDDAY MONDAY AND SPREADING ACROSS THE
ENTIRE REGION MONDAY AFTERNOON. SNOW WILL CONTINUE MONDAY NIGHT
THEN DIMINISH TUESDAY MORNING WITH THIS SYSTEM. WITH THE
ASSOCIATED SURFACE LOW TO TRACK SOUTH OF THE MASON DIXON LINE A
SWATH OF 2-4 INCH SNOW POSSIBLE SOUTH OF PITTSBURGH WITH 6 OR MORE
POSSIBLE IN THE HIGHER TERRAIN OF PRESTON...TUCKER AND GARRETT. AS
SUCH COORDINATED A WINTER STORM WATCH FROM MONDAY AFTERNOON INTO
TUESDAY MORNING FOR THESE COUNTIES. FROM PITTSBURGH NORTH 1 TO 3
INCHES POSSIBLE.
TEMPERATURES MONDAY MAINLY IN THE 20S. TEMPERATURES WILL DROP OFF
INTO THE TEENS LATE MONDAY NIGHT AS SYSTEM PASSES.
THE FUN IS NOT OVER HOWEVER...AS YET ANOTHER SHORTWAVE WILL BE
MOVING IN QUICKLY TUESDAY ON THE HEELS OF DEPARTING SYSTEM. THIS
SYSTEM WILL BRING LIGHT SNOW BACK INTO REGION BY TUESDAY
AFTERNOON. MODELS ARE NOT IN AGREEMENT ON TRACK WITH NAM FARTHER
NORTH THAN THE ECMWF. FOR NOW CHANCE POPS AS THIS WILL BE FURTHER
DEFINED IN LATER FORECASTS. NOT AS COLD TUESDAY WITH HIGH FROM THE
MID 20S NORTH TO LOWER 30S SOUTH.
&&
.LONG TERM /TUESDAY NIGHT THROUGH SATURDAY/...
MODELS ARE IN AGREEMENT IN DEPICTIONS OF WEAKENING ERN NORTH
AMERICAN TROF AND DEVELOPMENT OF A LOW OVR THE SW U.S. THE RESULTING
SPLIT FLOW WITH A NWD RETREAT OF THE NRN JET BRANCH SIGNALS A TEMP
MODERATION FOR THE ERN CONUS...INCLUDING THE UPR OH REGION.
THE LATTER HALF OF THE WEEK FORECAST THUS FEATURES A GRADUAL INCRS
IN TEMPS CUMULATING IN A WEEKEND PROG NRLY 10 DEGREES ABOVE THE
SEASONAL AVERAGES. A SHORTWAVE WITHIN THE ZONAL FLOW IS CURRENTLY
TIMED TO SPREAD PCPN OVR THE REGION ON FRIDAY...BUT PROGRESSION
LKS TO BE SUFFICIENTLY RAPID TO FORECAST A DRY WEEKEND.
&&
.AVIATION /15Z SUNDAY THROUGH THURSDAY/...
MVFR TO IFR WITH -SN AND STRATOCU CAN BE EXPECTED TDA AS LOW PRES
SLIDES ACRS THE UPR OH VALLEY REGION. SFC WIND WL VEER TO THE WEST
THIS AFTN FOLLOWING PASSAGE OF THE SFC TROF...AND SOME IMPROVEMENT
IS ANTICIPATED AS CLD BASES RISE...AND AS SNOW DIMINISHES BY EVE.
MORE RESTRICTIONS...INCLUDING WIDESPREAD IFR...ARE ANTICIPATED ON
MONDAY AS ANOTHER LOW IS FORECAST TO SPREAD SN OVR THE REGION.
.OUTLOOK.../SUNDAY NIGHT THROUGH THURSDAY/...
A SERIES OF DISTURBANCES WILL MAINTAIN PERIODIC RESTRICTIONS IN
SNOW SHOWERS AND STRATOCU THROUGH MIDWEEK.
&&
.PBZ WATCHES/WARNINGS/ADVISORIES...
MD...WINTER WEATHER ADVISORY UNTIL 7 PM EST THIS EVENING FOR MDZ001.
WINTER STORM WATCH FROM MONDAY AFTERNOON THROUGH TUESDAY
MORNING FOR MDZ001.
OH...NONE.
PA...WINTER WEATHER ADVISORY UNTIL 7 PM EST THIS EVENING FOR PAZ074-
076.
WV...WINTER WEATHER ADVISORY UNTIL 7 PM EST THIS EVENING FOR WVZ023-
041.
WINTER STORM WATCH FROM MONDAY AFTERNOON THROUGH TUESDAY
MORNING FOR WVZ023-041.
&&
$$
AREA FORECAST DISCUSSION...UPDATED AVIATION
NWS ST LOUIS MO
537 AM CST SUN FEB 3 2013
.SHORT TERM...
ISSUED AT 330 AM CST SUN FEB 3 2013
(TODAY THROUGH TUESDAY)
THANKS TO A COMPACT AND POTENT NW FLOW VORT MAX...SOME RATHER
IMPRESSIVE LOW LEVEL FORCING AND A POCKET OF STEEP MID LEVEL LAPSE
RATES...A NICE BAND OF 2-4 INCHES OF SNOW FELL LAST NIGHT WITH THE
HIGHEST AMOUNTS CENTERED RIGHT THROUGH THE ST LOUIS METRO. KUDOS
TO THE SAT AFTERNOON RUNS OF THE HRRR WHICH WAS THE SOLE MODEL
THAT COMPLETELY NAILED THE SNOWFALL FORECAST. THE SNOW HAS LONG
ENDED AND THE ASSOCIATED SURFACE FRONTAL SYSTEM WAS PASSING THRU
FAR ERN MO AT THIS TIME. GOOD CAA IS EXPECTED THIS MORNING IN THE
WAKE OF THE COLD FRONT WITH STRATUS IN THE LOW LEVEL NW FLOW FROM
ERN MO INTO IL. CAA SHOULD CEASE BY MIDDAY AS THE SURFACE RIDGE
SHIFTS INTO THE AREA WITH WEAK WAA DEVELOPING DURING THE AFTERNOON
IN CENTRAL MO AS THE SURFACE RIDGE CONTINUES TO DEPART TO THE
EAST. IN RESPONSE THE CLOUDS SHOULD ALSO EXIT EASTWARD.
SOUTHERLY WINDS WILL BECOME ESTABLISHED ACROSS THE AREA THIS
EVENING IN THE WAKE OF THE DEPARTING HIGH AND IN ADVANCE OF THE
NEXT COLD FRONTAL SYSTEM...WITH STRONG LOW LEVEL WAA ENSUING
DURING THE LATE EVENING AND OVERNIGHT HOURS. THIS FLOW REGIME
COMBINED WITH INCREASING AND THICKENING CLOUDS OVERNIGHT WOULD
SUPPORT MIN TEMPS OCCURING DURING THE EVENING AND THEN RISING
OVERNIGHT. THE SNOW COVER COULD BE PROBLEMATIC IF THE SURFACE WINDS
REMAIN LIGHTER THAN EXPECTED...ALLOWING FOR A GREATER EVENING TEMP
FALL THAN CURRENTLY FCST. ATTM IT APPEARS THAT SHOWERS SHOULD
DEVELOP ACROSS ERN OK DURING THE OVERNIGHT HOURS AND SPREAD NEWD
ACROSS SE MO AND SRN IL BETWEEN 15-18Z MONDAY IN RESPONSE TO
INCREASING LARGE SCALE ASCENT AND STRONG LOW LEVEL MOISTURE
TRANSPORT/CONVERGENCE. GIVEN THE WAA REGIME AND EXPECTED ONSET OF
PCPN...SURFACE TEMPERATURES ARE EXPECTED TO BE ABOVE FREEZING AND
CONTINUE TO WARM THROUGH THE MORNING AHEAD OF THE FRONT...ALTHOUGH
THAT WARMING COULD BE RETARDED A BIT BY DIABATIC COOLING. STRONG
CAA IS EXPECTED IN THE WAKE OF THE COLD FRONT DRIVING SEWD THRU
THE MORNING AND EARLY AFTERNOON. HIGH PRESSURE WILL THEN BUILD
INTO THE AREA ON MONDAY NIGHT AND THEN YET ANOTHER NW FLOW SHORT
WAVE WILL BRING A WEAK FRONT THROUGH THE REGION ON TUESDAY.
GLASS
&&
.LONG TERM...
ISSUED AT 330 AM CST SUN FEB 3 2013
(WEDNESDAY THROUGH SATURDAY)
A BIG PATTERN CHANGE WILL EVOLVE DURING THIS PERIOD AS THE BROAD
LONG WAVE TROF THAT HAS BEEN SENDING US THE PARADE OF NW FLOW
SHORT WAVES FINALLY DEPARTS WELL INTO THE ATLANTIC. HEIGHTS ALOFT
RISE IN RESPONSE...WITH THE FLOW ALOFT BECOMING QUASI-ZONAL THRU
THE NATIONS MIDSECTION WITH EMBEDDED LOW AMPLITUDE SHORT WAVES. ONE
OF THESE WAVES WILL BRING ANOTHER COLD FRONT THROUGH ON THURSDAY
WITH AN ACCOMPANING CHANCE OF SHOWERS. THE FLOW ALOFT CONTINUES TO
EVOLVE THROUGH LATE WEEK WITH THE DEVELOPMENT OF A DEEP WRN TROF.
CURRENT INDICATIONS ARE THAT THIS TROF MAY BRING A THREAT OF
SHOWERS AND THUNDERSTORMS BY LATE NEXT WEEKEND AS AN INITIAL WAVE
MIGRATES INTO THE CENTRAL U.S.. OVERALL THE EXTENDED PERIOD SHOULD
BE MARKED BY ABOVE AVERAGE TEMPERATURES.
GLASS
&&
.AVIATION...
ISSUED AT 531 AM CST SUN FEB 3 2013
NW WINDS WITH GUSTS TO AROUND 25 KTS EXPECTED THRU AT LEAST MID
MORNING. WINDS WILL DIMINISH SOMEWHAT THRU THE AFTERNOON. CLOUDS
SHUD REMAIN IN PLACE THRU THIS MORNING...BUT SHUD REMAIN VFR AND
MOVE E BY EARLY AFTERNOON. WINDS WILL BECOME SLY TONIGHT AND
REMAIN BELOW 8 KTS.
SPECIFICS FOR KSTL...VFR AND DRY THRU THE PERIOD. NWLY WINDS WITH
GUSTS TO AROUND 25 KTS WILL DIMINISH THIS AFTERNOON WITH CLOUDS
CLEARING OUT AROUND THE SAME TIME. WINDS SLY TONIGHT AOB 10 KTS.
TILLY
&&
.LSX WATCHES/WARNINGS/ADVISORIES...
MO...NONE.
IL...NONE.
&&
$$
WFO LSX
AREA FORECAST DISCUSSION
NWS TUCSON AZ
910 AM MST SUN FEB 3 2013
.SYNOPSIS...THERE IS A CHANCE OF SHOWERS MAINLY NEAR MOUNTAINS
THROUGH THIS EVENING. DRY CONDITIONS WITH DAYTIME TEMPERATURES
GENERALLY SEVERAL DEGREES ABOVE NORMAL WILL THEN PREVAIL MONDAY
THROUGH THURSDAY. A LOW PRESSURE SYSTEM NORTH OF THE AREA IS
EXPECTED TO BRING BREEZY CONDITIONS AND COOLER TEMPERATURES FRIDAY
INTO SATURDAY.
&&
.DISCUSSION...CLOUDY SKIES ACROSS SE AZ AT THIS TIME AS ABUNDANT
MAINLY MID AND HIGH-LEVEL MOISTURE MOVES NEWD ACROSS THE AREA.
DEWPOINTS VALID 16Z RANGED FROM THE LOWER 20S F NE OF TUCSON TO THE
LOWER 40S F ACROSS WRN PIMA COUNTY. SURFACE TEMPS VALID 16Z WERE
NEARLY 5-15 DEGS F WARMER VERSUS 24 HOURS AGO. 03/12Z KTWC SOUNDING
TOTAL PRECIP WATER VALUE WAS NEAR 0.45 INCH. THE PROFILE EXHIBITED A
VERY DRY SURFACE-700 MB LAYER...AND THE COLUMN WAS SATURATED ABOVE
600 MB. 03/12Z UPPER AIR PLOTS INDICATED 565 DM LOW PRESSURE
CENTERED OVER FAR NRN CALIFORNIA...AND SHORTWAVE TROUGH WAS JUST OFF
THE NRN/CENTRAL BAJA CALIFORNIA COAST. LIGHT-MODERATE GENERALLY SWLY
FLOW WAS OVER SE AZ.
BASED ON THE 03/12Z NAM AND RUC HRRR...AS WELL AS RADAR TRENDS...
OPTED TO REDUCE INHERITED POPS ESPECIALLY FOR LOCALES BELOW 5000
FEET TODAY. THE BEST CHANCE OF MEASURABLE PRECIP THIS MORNING
APPEARS TO BE WEST OF TUCSON. FOR THIS AFTERNOON...OPTED FOR SLIGHT
CHANCE OF SHOWERS ACROSS LOWER ELEVATIONS...AND MAINTAINED
CHANCE-CATEGORY POPS ACROSS THE MOUNTAINS. MAX QPF/S EXPECTED TO BE
ABOUT FIVE HUNDREDTHS OF AN INCH OR SO.
BULK OF DEEPER MOISTURE IS PROGGED TO BE WELL EAST OF THE AREA LATER
THIS EVENING. FOR NOW WILL MAINTAIN A SLIGHT CHANCE OF SHOWERS THIS
EVENING ACROSS GREENLEE...GRAHAM..AND COCHISE COUNTIES WITH
PRECIP-FREE CONDITIONS ELSEWHERE. DRY CONDITIONS AREA-WIDE LATE
TONIGHT EXCEPT FOR A SLIGHT CHANCE OF SNOW SHOWERS ACROSS THE WHITE
MOUNTAINS.
DRY CONDITIONS WITH ABOVE NORMAL DAYTIME TEMPS TO PREVAIL MON-THUR.
THEREAFTER...GFS/ECWMF WERE FAIRLY SIMILAR WITH DEPICTING UPPER
TROUGH OVER THE WRN CONUS FRI-SAT. THE BULK OF DEEPER MOISTURE IS
PROGGED TO BE NORTH OF THIS FORECAST AREA. THUS...AT THIS TIME
APPEARS THAT THE MAIN IMPACT ON SE AZ FROM THIS SYSTEM WILL BE SOME
BREEZINESS AND A MARKED COOLING TREND.
COOLER TODAY VERSUS TEMPS ACHIEVED SAT AFTERNOON...WITH HIGH TEMPS
TODAY TO BE QUITE CLOSE TO NORMAL. WARMER MON-TUE THEN NO
SIGNIFICANT CHANGE IN DAYTIME TEMPS WED-THUR. COOLING TREND TO THEN
OCCUR FRI-SAT...WITH HIGH TEMPS SAT FORECAST AT THIS TIME TO BE
NEARLY 10 DEGS F OR SO BELOW NORMAL.
&&
.AVIATION...BKN-OVC CLOUDS GENERALLY 8-12K FT AGL THRU THIS EVENING
THEN DECREASING CLOUDS FROM WEST TO EAST 06Z-12Z MONDAY. ISOLD-SCT
-SHRA MAINLY NEAR HIGHER TERRAIN UNTIL ABOUT 04/06Z THEN DRY
CONDITIONS AREA WIDE BY EARLY MONDAY MORNING. SURFACE WIND LESS THAN
10 KTS THRU EARLY MONDAY MORNING OR 04/12Z. AVIATION DISCUSSION NOT
UPDATED FOR TAF AMENDMENTS.
&&
.FIRE WEATHER...THERE IS A CHANCE OF SHOWERS MAINLY NEAR MOUNTAINS
INTO THIS EVENING. OTHERWISE...DRY CONDITIONS WITH DAYTIME
TEMPERATURES GENERALLY SEVERAL DEGREES ABOVE NORMAL WILL OCCUR
MONDAY THROUGH THURSDAY. THEREAFTER...EXPECT BREEZY CONDITIONS AND
COOLER TEMPERATURES FRIDAY INTO SATURDAY AS A LOW PRESSURE SYSTEM
MOVES NORTH OF THE AREA.
&&
.TWC WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
VISIT US ON FACEBOOK...TWITTER...YOUTUBE...AND AT WEATHER.GOV/TUCSON
AREA FORECAST DISCUSSION
NWS ALBANY NY
1234 PM EST SUN FEB 3 2013
.SYNOPSIS...
ANOTHER CLIPPER LOW WILL APPROACH THE REGION TODAY WITH SOME SNOW
SHOWERS IN THE AFTERNOON INTO THE EVENING. SOME LAKE EFFECT
SNOWFALL WILL IMPACT THE WESTERN ADIRONDACKS AND THE MOHAWK VALLEY
ON MONDAY. BLUSTERY AND COLD CONDITIONS ARE EXPECTED TO OPEN THE
WEEK...BEFORE HIGH PRESSURE BUILDS IN MONDAY NIGHT INTO TUESDAY.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
AS OF 1230 PM EST...ONLY CHANGE TO THE FORECAST WAS TO DELAY THE
ONSET TIME OF ANY LIGHT SNOW/SNOW SHOWERS A COUPLE OF MORE HOURS.
REGIONAL RADAR AND SURFACE OBS SHOW VERY LIGHT SNOW ACROSS PORTIONS
OF WESTERN NY AND PA. HRRR EXPERIMENTAL REFLECTIVITY AND LOCAL WRF
MODEL SHOW LESS THAN IMPRESSIVE FORECAST RADAR RETURNS THROUGH THE
REMAINDER OF THE DAY AS WE WILL LOWER POPS A LITTLE FURTHER.
AS OF 924 AM EST...ANOTHER CLIPPER LOW WILL BE APPROACHING FROM
THE NRN GREAT LAKES REGION TODAY. THE SHORT-WAVE SHOWS UP WELL ON
THE WATER VAPOR LOOP THIS MORNING OVER THE WESTERN GREAT LAKES AND
NORTHERN MICHIGAN. IT WILL QUICKLY APPROACH IN THE W/NW FLOW. THE
TROUGH AXIS WILL SHARPEN...AND THE NAM/GFS/CAN GUIDANCE SHOWS SCT
SNOW SHOWERS MOVING INTO WESTERN PARTS OF THE AREA DURING THE
AFTERNOON HOURS. THE SHORTWAVE ENERGY WITH THE CLIPPER WILL
ATTEMPT TO PHASE WITH COASTAL LOW WELL SOUTH AND EAST OF CAPE COD
TONIGHT. AN INVERTED SFC TROUGH EXTENDING NORTH AND WEST OF THE
OCEAN CYCLONE WILL ACT AS FOCUSING MECHANISM FOR THE LIGHT SNOW
SHOWERS.
ALTHOUGH SKIES ARE STARTING THE DAY CLEAR TO PARTLY CLOUDY ACROSS
THE REGION...CLOUDS WILL INCREASE DURING THE AFTERNOON AS THE
CLIPPER APPROACHES. MAX TEMPS WILL STILL RUN BELOW NORMAL WITH
H850 TEMPS IN THE -12C TO -16C RANGE ACROSS THE REGION. HIGHS WILL
BE IN THE MID 20S TO NEAR 30F IN THE VALLEYS...AND UPPER TEEN TO
M20S OVER THE MTNS.
ANY ACCUMULATIONS WILL BE ON THE LIGHT SIDE PRIOR TO NIGHTFALL
WITH A COATING TO A HALF AN INCH IN SOME LOCATIONS.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH TUESDAY NIGHT/...
TONIGHT...FAVORED THE NAM SOLUTION AND THE CANADIAN REGIONAL
TONIGHT. ALSO LEANED CLOSER TO THE HIGHER NAM OR MET MOS POPS. THE
SHORT-WAVE WITH THE CLIPPER PHASES INTO THE DOWN STREAM UPPER
TROUGH...AND THE LONG-WAVE TROUGH BECOMES NEGATIVELY TILTED OVER
ERN NY AND WRN NEW ENGLAND. THE DIFFERENTIAL CYCLONIC VORTICITY
ADVECTION WITH THE TROUGH...AND THE MID AND UPPER LEVEL
DEFORMATION ZONE KICK OFF A ROBUST AREA OF LIGHT SNOW PRIOR TO
MIDNIGHT. CONTINUED THE PREVIOUS FORECAST TREND OF LIKELY AND HIGH
CHC POPS HEAVILY BASED ON THE NAM. GREAT LAKES MOISTURE MAY BE
UTILIZED...AND A MODEST BAND OF SNOW MAY EXTEND DOWN THE MOHAWK
VALLEY OVERNIGHT IMPACTING THE CAPITAL REGION WITH ANOTHER
INVERTED SFC TROUGH. ALSO...SOME WESTERLY UPSLOPE SNOWFALL MAY
MATERIALIZE BEFORE MIDNIGHT OVER THE SRN GREENS...TACONICS...NRN
BERKS...AND WRN DACKS.
BUFKIT PROFILES SHOW DEEP SATURATION TO 12-15 KFT AT KALB WITH
DECENT SNOW GROWTH POTENTIAL OVERNIGHT ACCORDING TO THE NAM. SNOW
RATIOS OF 15-20:1 WOULD YIELD UP TO AN INCH OR SO AROUND THE
CAPITAL REGION /ROUGHLY A HALF AN INCH TO TWO INCHES IN THE
VALLEYS/...AND 1 TO 4 INCHES OVER THE HIGHER TERRAIN /HIGHEST
TOTALS OVER THE SRN GREENS AND WRN DACKS/.
THERE ARE SOME INDICATIONS THAT AN ONTARIO LAKE EFFECT BAND MAY FORM
BETWEEN MIDNIGHT AND 6 AM . THIS BAND WOULD INITIALLY IMPACT THE
WRN DACKS...AND THEN SHIFT S/SE TOWARDS THE MOHAWK RIVER VALLEY.
OUR CONFIDENCE IS STILL NOT HIGH FOR A HEADLINE...BUT WE WILL
CONTINUE THE MENTION OF SOME LAKE EFFECT SNOWFALL FOR HERKIMER
COUNTY IN THE HAZARDOUS WX OUTLOOK.
MON-MON NIGHT...THE WORK WEEK OPENS WITH BLUSTERY AND COLD
CONDITIONS...AS A DEEPENING AND INTENSIFYING LOW PRESSURE SYSTEM
MOVES TOWARD THE GULF OF ST LAWRENCE...AN ARCTIC HIGH PRESSURE
ATTEMPTS TO BUILD IN FROM THE GREAT LAKES REGION AND ONTARIO. W/NW
WINDS OF 10 TO 20 MPH WILL BE COMMON WITH SOME GUSTS AROUND 30-35
MPH. WIND CHILLS WILL BE IN THE SINGLE DIGITS AND TEENS.
WESTERLY UPSLOPE SNOW SHOWERS OVER THE SRN GREENS AND WRN DACKS
WILL END DURING THE AFTERNOON WITH ADDITIONAL LIGHT ACCUMULATIONS.
THE MESOSCALE MODELS /HIRES WRF AND CANADIAN REGIONAL/ ARE SHOWING
A LAKE EFFECT BAND IN THE W/NW FLOW POTENTIALLY IMPACTING THE
W-CNTRL MOHAWK VALLEY...AND THE NRN CATSKILLS. THE INLAND
EXTENSION OF THIS BAND IS IN QUESTION BASED ON THE PAST CSTAR
RESEARCH. ALSO THE BAND IS TRANSITORY...AND DRIER AIR MAY GET
ENTRAINED NIXING THE INLAND EXTENSION. THE INVERSION HEIGHTS ON
THE KUCA NAM BUFKIT SOUNDING DUE REMAIN AT 8-10 KFT AGL WITH
MODERATE TO EXTREME INSTABILITY. TYPICALLY LAKE BANDS IN OUR AREA
PER THE CSTAR RESEARCH FAVOR CONDITIONAL INSTABILITY. THE BANDS
MAY STAY TRAPPED CLOSER TO THE LAKE SHORE.
IT APPEARS EXTREME SRN HERKIMER AND NW SCHOHARIE COUNTY
MAY GET GRAZED WITH AN INCH OR TWO OF SNOWFALL. THIS POTENTIAL
LAKE BAND WILL GET MONITORED CLOSELY DURING THE DAY. COATINGS TO
HALF INCH OF SNOWFALL WILL ALSO BE POSSIBLE IN THE FAVORED WESTERLY
UPSLOPE AREAS OF THE TACONICS...BERKS...AND SRN GREENS OF VT. 1-3
INCHES OF ADDITIONAL SNOWFALL IS EXPECTED FOR THE W-CNTRL MOHAWK
VALLEY AND NRN CATSKILLS.
IN THE COLD ADVECTION REGIME...850 TEMPS FALL TO -15C TO -20C
NORTH OF THE CAPITAL REGION. MAX TEMPS WILL CONTINUE TO RUN BELOW
NORMAL WITH TEENS TO M20S OVER THE HILLS AND MTNS...AND L20S TO
NEAR 30F IN THE VALLEY AREAS. TEMPS MAY STEADY OR FALL DURING THE
DAY.
DECREASING WINDS AND FRIGID CONDITIONS ARE ANTICIPATED MON NIGHT
WITH HIGH PRESSURE BUILDING IN WITH LOWS ZERO TO 12 BELOW OVER THE
ADIRONDACK PARK...AND SRN GREENS...SINGLE DIGITS EVERYWHERE
ELSE...EXCEPT 10-15F IN THE MID HUDSON VALLEY AND SRN LITCHFIELD
COUNTY. WIND CHILL VALUES FALL JUST SHORT OF ADVISORY CRITERIA OVER
THE SRN DACKS.
TUESDAY-TUESDAY NIGHT...QUIET AND COLD WEATHER IS EXPECTED DURING
THE DAY WITH ARCTIC HIGH PRESSURE BRIEFLY RIDGING IN OVER THE
REGION. MAX TEMPS WILL BE RUNNING ABOUT 10 DEGREES BELOW NORMAL.
ANOTHER CLIPPER WILL BE RACING TOWARDS THE REGION FROM THE CNTRL-
ERN GREAT LAKES REGION BY NIGHTFALL. THE MEDIUM RANGE GUIDANCE
INDICATES SOME LIGHT SNOWFALL MAY OVERSPREAD THE REGION AGAIN WITH
THIS CLIPPER TUE NIGHT INTO WED. CHC POPS WERE USED FOR LIGHT SNOW
HERE.
&&
.LONG TERM /WEDNESDAY THROUGH SATURDAY/...
MODEL GUIDANCE IS IN FAIRLY GOOD AGREEMENT KEEPING THE REGION UNDER
A LONGWAVE TROUGH. HOWEVER...THERE ARE DIFFERENCES IN THE AMPLITUDE
OF THE SHORT WAVE TROUGHS MOVING THROUGH PARTICULARLY LATE IN THE
WEEK.
A SHORT WAVE TROUGH AND ITS ASSOCIATED WEAK SURFACE SYSTEM WILL MOVE
OFF TO OUR EAST ON WEDNESDAY TAKING ANY LINGERING PRECIPITATION/SNOW
WITH IT. FLOW ALOFT FLATTENS AND RIDGING BUILDS IN AT THE SURFACE
AND IN THE LOW LEVELS OF THE ATMOSPHERE ON THURSDAY BETWEEN SHORT
WAVE TROUGHS.
THE ECMWF DEVELOPS A DEEPER TROUGH THAN THE GFS AS IT MOVES ACROSS
THE GREAT LAKES REGION INTO THE EASTERN UNITED STATES LATE IN THE
WEEK. THIS HAS A BIG IMPACT ON THE POTENTIAL DEVELOPMENT OF THE
SURFACE SYSTEM. THE ECMWF INDICATES AN UPPER LOW SHOULD CLOSE OFF ON
FRIDAY OVER THE MID ATLANTIC/NEW YORK METRO REGION WITH CYCLOGENESIS
OCCURRING OVER DELMARVA BY 12Z/FRIDAY...WITH THE LOW THEN HEADING
NORTHEASTWARD DURING THE DAY OVER LONG ISLAND AND EASTERN NEW
ENGLAND. THE GFS PAINTS A DIFFERENT PICTURE WITH A LOW DEVELOPING
THE GREAT LAKES REGION THURSDAY AND TRACKING IT EASTWARD ACROSS THE
NORTHEAST ON FRIDAY. THE GFS HAS SHOWN RUN-TO-RUN CONSISTENCY AND
THE 12Z/ECMWF IS SIMILAR TO THE GFS SOLUTIONS. THE GFSENSEMBLE
MEMBERS INDICATE A LARGE SPREAD IN POTENTIAL LOW POSITIONS. AT THIS
TIME...HAVE FAVORED THE LESS AMPLIFIED SOLUTION MOVING THE SURFACE
LOW ACROSS THE NORTHEAST ON FRIDAY. THIS SET UP WILL BRING SOME
LIGHT SNOW TO THE REGION. WILL NEED TO WATCH TO SEE IF THE ECMWF IS
CATCHING ON TO SOMETHING FOR A MORE SIGNIFICANT SNOW EVENT.
MORE RIDGING IS EXPECTED TO BUILD INTO THE REGION NEXT WEEKEND.
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-9TH:
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 /18Z SUNDAY THROUGH FRIDAY/...
VFR CONDITIONS ARE IN PLACE EARLY THIS AFTN. SKIES ARE NEARLY CLEAR
ACROSS NORTHERN PARTS OF THE AREA...WITH BKN-OVC MID LEVEL CLOUDS
ACROSS SOUTHERN AREAS. A BRIEF PERIOD OF MVFR CIGS IS POSSIBLE
THROUGH THE AFTN AT KPSF...OTHERWISE ALL SITES SHOULD REMAIN VFR
WITH NO PRECIPITATION THROUGH MID AFTN.
SKIES WILL BECOME BKN-OVC BY LATE THIS AFTN/EARLY THIS EVENING AS A
CLIPPER SYSTEM APPROACHES FROM THE GREAT LAKES REGION. SOME SNOW
SHOWERS OR FLURRIES ARE POSSIBLE WITH THIS SYSTEM...ALTHOUGH
MOISTURE IS LIMITED AND THE BEST CHC APPEARS ACROSS THE HIGH
TERRAIN. FOR NOW...WILL ONLY GO WITH VCSH AT ALL TAF SITES FROM
ABOUT 22Z-23Z UNTIL 08Z-10Z WITH CONTINUED VFR CIGS. WHILE A BRIEF
PERIOD OF MVFR VSBYS CANNOT BE RULED OUT WITHIN ANY SNOW
SHOWER...THE TIMING AND EXTENT IS UNKNOWN AT THIS TIME TO ACCURATELY
FORECAST IN THE TAFS.
BEHIND THIS CLIPPER...SOME LAKE EFFECT SNOW WILL DEVELOP OFF LAKE
ONTARIO. MOST OF THIS ACTIVITY WILL REMAIN TO THE WEST OF THE
REGION...ALTHOUGH IT/S POSSIBLE THAT THE BAND COULD REACH INTO THE
CAPITAL REGION/BERKSHIRES. DUE TO THE UNCERTAINTY...WILL ONLY GO
WITH A VCSH RIGHT NOW FOR KALB/KPSF FOR THE MID TO LATE MORNING
HOURS ON MONDAY.
WINDS ARE EXPECTED TO BE LIGHT AND VARIABLE THIS AFTN INTO THIS
EVENING. BEHIND THE CLIPPER...WESTERLY WINDS WILL INCREASE TO 5-10
KTS. AFTER SUNRISE ON MONDAY...DAYTIME MIXING WILL ALLOW FOR SOME
STRONGER GUSTS WITH WINDS OF 10-15 KTS AND GUSTS OF 20-25 KTS...ESP
FOR KALB/KPSF.
OUTLOOK...
MON NIGHT-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.
WED NIGHT-THU...VFR. NO SIG WX.
THU NIGHT-FRI. VFR/MVFR/IFR. CHC -SN.
&&
.HYDROLOGY...
HYDRO PROBLEMS ARE NOT ANTICIPATED THE NEXT 5 DAYS WITH COLD TEMPS
AND LIGHT SNOW EVENTS MAINLY IMPACTING THE ALBANY HYDRO SERVICE AREA.
SOME HYDRO GAGES ARE EXPERIENCING ICE EFFECTS AROUND THE HSA. THE
BELOW NORMAL TEMPERATURES WILL ALLOW ICE TO REFORM AND THICKEN ON ALL
BODIES OF WATER THROUGH THE MID WEEK.
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...BGM/FRUGIS/WASULA
SHORT TERM...WASULA
LONG TERM...IAA
AVIATION...FRUGIS
HYDROLOGY...BGM/WASULA
AREA FORECAST DISCUSSION
NWS GRAY ME
1223 PM EST SUN FEB 3 2013
.SYNOPSIS...
LOW PRESSURE WILL DEVELOP IN THE ATLANTIC WELL EAST OF THE REGION
TODAY AND MOVE NORTHEAST. A COLD...BRISK FLOW WILL BEGIN ON
MONDAY...FOLLOWED BY THE PASSAGE OF A WEAK RIDGE OF HIGH PRESSURE
THROUGH MIDWEEK. LOW PRESSURE WILL APPROACH THE MID ATLANTIC
REGION THURSDAY AND HEAD NORTHEAST.
&&
.NEAR TERM /UNTIL 7 PM THIS EVENING/...
NOON UPDATE...UPDATED FORECAST BASED ON LATEST SURFACE
OBSERVATIONS...WITH LITTLE CHANGE TO OVERALL FORECAST. A LITTLE
LIGHT SNOW OR FLURRY ACTIVITY POSSIBLE IN SOUTHWESTERN ME AND
SOUTHEASTERN NH THIS AFTERNOON...OTHERWISE INCREASING CLOUDINESS
ACROSS REGION AS OCEAN LOW STARTS TO DEVELOP AND MOVE NORTHEAST.
830 AM UPDATE...SKIES ARE SUNNY IN MANY AREAS AND PARTLY SUNNY IN
ALONG THE COAST WITH SOME HIGH THIN CLOUDS OVERHEAD. THE MORE
OPAQUE CLOUDS ARE NOW JUST OFF THE COAST. TEMPS ACROSS INTERIOR
AND MOUNTAINS ARE A BIT COLDER THAN ORIGINAL FORECAST DUE TO
MOSTLY CLEAR SKIES ACROSS THE REGION. HAVE ADJUST SKY...TEMP AND
DEW POINT FCST TO REFLECT CURRENT CONDITIONS. CLOUDS WILL BE ON
THE INCREASE FROM SOUTH TO NORTH DURING THE DAY AS OCEAN LOW
DEVELOPS AND STARTS MOVING NORTHEAST.
UPDATE...BROUGHT LOW TEMPS UP ALONG THE COAST AND INTERIOR...WHERE
CIRRUS SHIELD IS KEEPING ANY RADIATIONAL COOLING AT BAY. HAVE ALSO
BLENDED IN THE LATEST HRRR POP TO ACCOUNT FOR CURRENT
OBSERVATIONAL TRENDS IN SN ALONG THE COAST AND OVER THE WATERS.
LATEST DATA FROM GYX 88D INDICATES SW MOVING ECHOES OVER THE
WATERS...ON A TRAJECTORY FOR COASTAL YORK AND ROCKINGHAM COUNTIES.
THIS IS ON THE LEADING EDGE OF NELY SURGE WORKING FROM DOWNEAST.
WHETHER OR NOT THIS MAINTAINS ITSELF LONG ENOUGH TO WORK INLAND IS
STILL IN QUESTION...BUT HAVE MADE SURE THAT AT LEAST CHC POP IS
THERE FOR SERN NH AND SWRN ME THIS MORNING. TIME OF ARRIVAL TOOL
PLACES THE LEADING EDGE AT KPSM AROUND 16 OR 17Z...AND THIS IS
REFLECTED IN POP TRENDS.
PREVIOUS DISCUSSION...WEAK LEAD S/WV TROF LIFTING THRU THE
LARGER ERN L/WV TROF IS SUPPORTING A WEAK LOW PRES SKIRTING THRU
THE GULF OF MAINE. CLOUD SHIELD IS ROUGHLY BISECTING THE
CWFA...WITH VERY LIGHT SN OCCURRING ACROSS SERN NH AND EXTREME
SWRN ME. GENERALLY HAVE SCHC TO CHC POP FOR COASTAL ZONES
TODAY...AS OVERALL SYSTEM ORGANIZATION WILL BE LACKING.
ONE FEATURE OF NOTE IS THE SFC TROF THAT EXTENDS BACK TO THE NW OF
THE WEAK LOW PRES CENTER. WINDS ARE NW AT MISM1...KLEW...AND KPWM.
WHILE AT KSFM AND IOSN3 WINDS ARE WSW. WITHIN THIS TROF...MORE
CONVECTIVE SHSN HAVE BEEN OCCURRING AND PROPAGATING WITH THE LLVL
FLOW. SOME BRIEFLY HEAVIER SNOWFALL RATES ARE PSBL IN ANY OF THESE
SHSN. MESOSCALE MODEL GUIDANCE WAS HANDLING THIS FEATURE VERY WELL
THIS MORNING...WITH THE HRRR AND LOCAL WRF FEATURING HIGH POP
WITHIN THE TROF AXIS. HAVE STARTED POP GRIDS HERE AND BLENDED
TOWARDS THIS AFTN. AS STRONGER S/WV TROF OFF THE MIDATLANTIC
REIGNITES SFC CYCLOGENESIS S OF NEW ENGLAND TODAY...WINDS WILL
BEGIN TO BECOME MORE NLY AND NELY ACROSS THE CWFA AND WATERS.
MESOSCALE MODELS FAVOR SHSN CONTINUING WITH THE WEAK SFC TROF AS
IT PUSHES BACK TO THE SW TODAY. THIS COULD KEEP THE NH SEACOAST
AND EXTREME SWRN ME IN THE SHSN A LITTLE LONGER THAN THE REST OF
THE COAST. HAVE LINGERED THE CHC POP IN THIS AREA INTO THE AFTN TO
ACCOUNT FOR THIS POSSIBILITY.
OTHERWISE...UPSLOPE SHSN GRADUALLY WIND DOWN THIS MORNING. A FEW
POCKETS WHERE CLOUDS SCATTER OUT WILL RADIATE WELL...AND LOWS WILL
APPROACH SUB-ZERO. THIS AFTN...CIRRUS SHIELD WILL PREVENT IDEAL
DIURNAL HEATING...AND HIGHS IN THE 20S TO NEAR 30 ARE A BLEND OF
THE MAV AND LOCAL WRF GUIDANCE.
&&
.SHORT TERM /7 PM THIS EVENING THROUGH 6 PM MONDAY/...
UPR TROF CROSSES THE AREA OVERNIGHT INTO MON. WILL SEE CLOUDS
INCREASE AHEAD OF IT...ALONG WITH MORE WIDESPREAD
SHSN. THIS IS ESPECIALLY TRUE IN THE MTNS...WHERE DEVELOPING WLY
FLOW WILL SET OFF ANOTHER ROUND OF UPSLOPE SN. THE PROGRESSIVE
FLOW WILL KICK SFC LOW PRES WELL OUT TO SEA THOUGH...AND HAVE CUT
BACK ON AREA OF CHC POP FOR A LARGE PORTION OF THE CWFA. GREATEST
THREAT FOR STEADIER PCPN WILL BE ON THE MIDCOAST...WHERE LOW PRES
CUTTING WWD ACROSS THE BAROCLINIC ZONE AS IT RAPIDLY DEEPENS MAY
PASS CLOSER ENOUGH TO DOWNEAST MAINE TO BRUSH AREAS AROUND
PENOBSCOT BAY WITH -SN.
WITH THE PASSAGE OF THE UPR TROF...STRONG CAA KICKS IN EARLY MON.
DEEP MIXING LAYER WILL SUPPORT STRONGER WIND GUSTS TO TRANSLATE TO
THE SFC. ATTM GUSTS AROUND 30 KTS LOOK LIKELY...WITH A LOW
PROBABILITY FOR HIGHER GUSTS DEPENDING ON EXACT STRENGTH AND
TRACK OF LOW PRES. THE CLOSER TO THE CWFA...THE TIGHTER THE PRES
GRADIENT WILL BE.
&&
.LONG TERM /MONDAY NIGHT THROUGH SATURDAY/...
A BRISK NORTHWEST FLOW WILL ALLOW FOR MORE ARCTIC AIR TO ENTER THE
REGION MONDAY NIGHT BEHIND A DEPARTING FULL FLEDGED STORM OVER THE
CANADIAN MARITIMES. WITH THE EXCEPTION OF A FEW FLURRIES FROM A
SYSTEM WELL OFF THE EAST COAST ON WEDNESDAY...EXPECT DRY AND
MAINLY CLEAR CONDITIONS. MORE MOISTURE AND CLOUDINESS WILL HANG UP
IN THE MOUNTAINS HOWEVER DURING THIS PERIOD.
ALL BETS ARE OFF LATE IN THE WEEK AS THERE ARE GREAT DISCREPANCIES
WITH THE 00Z MODEL RUN. THE GGEM AND GFS BRING A SYSTEM TO OUR
WEST THURSDAY NIGHT INTO FRIDAY. THE LATEST EURO RUN IS MUCH MORE
WELL DEFINED WITH A STRONG EAST COAST LOW OVER THE DELMARVA REGION
BY 12Z FRIDAY. THIS SYSTEM SLOWLY MOVES NORTHEAST...WITH A BLOCKING
HIGH TO THE NORTH OF MAINE DURING THIS PERIOD. FOR THE TIME
BEING...WE HAVE CHANCE POPS FOR THIS SYSTEM FOR THE DAY 6 PERIOD.
INTERESTED TO SEE IF THE 12Z RUNS HOLD ONTO THIS SLOW MOVING
FEATURE. ASTRONOMICAL TIDES WILL BE RELATIVELY HIGH DURING THIS
PERIOD AS WELL.
&&
.AVIATION /17Z SUNDAY THROUGH THURSDAY/...
SHORT TERM...AREAS OF MVFR WITH LOCAL IFR CONDS THIS MORNING ALONG
COAST. DIVIDING LINE WILL BE BETWEEN KCON AND KPSM...RUNNING ENE
THRU KAUG AND KRKD. N OF THIS LINE EXPECT NO PCPN...EXCEPT FOR
KHIE WHERE UPSLOPE SHSN WILL GRADUALLY WIND DOWN THIS MORNING.
BECOMING VFR THIS AFTN
LATE SUN THERE IS A LOW PROBABILITY OF MVFR OR IFR SN TO WORK INTO
KRKD IN ASSOCIATION WITH AN OCEAN LOW PRES. MORE LIKELY IS THAT
BEHIND LOW PRES ON MON STRONG WLY WINDS DEVELOP...WITH GUSTS AOA
25 KT. UPSLOPE SHSN WILL BEGIN AGAIN FOR KHIE AND KLEB LATE SUN
THRU MON.
LONG TERM...CONDITIONS MAY DETERIORATE ONCE AGAIN BY FRIDAY AS LOW
PRESSURE APPROACHES.
&&
.MARINE...
SHORT TERM...WINDS AND SEAS REMAIN BELOW SCA THRESHOLDS ATTM.
DEVELOPING LOW PRES S OF NEW ENGLAND TODAY WILL CREATE NE FLOW ON
THE WATERS THRU THIS AFTN. COULD SEE WINDS APPROACH SCA GUSTS
LATER TODAY AS A RESULT. WITH THE PASSAGE OF A COLD FNT
MON...STRONG WLY FLOW WILL DEVELOP DURING THE MORNING AND INTO THE
AFTN. WINDS COULD GUST ABOVE GALE FORCE INTO TUE.
LONG TERM...GALES ARE POSSIBLE ONCE AGAIN ON FRIDAY.
&&
.GYX WATCHES/WARNINGS/ADVISORIES...
ME...NONE.
NH...NONE.
MARINE...GALE WATCH FROM MONDAY MORNING THROUGH LATE MONDAY NIGHT FOR
ANZ150>154.
&&
$$
SYNOPSIS...
NEAR TERM...JENSENIUS
SHORT TERM...
LONG TERM...
AVIATION...
MARINE...
AREA FORECAST DISCUSSION
NWS PITTSBURGH PA
410 PM EST SUN FEB 3 2013
.SYNOPSIS...
ALTHOUGH SNOW WILL BRIEFLY DECREASE IN MOST LOCATIONS
OVERNIGHT...LOW PRESSURE WILL BRING ANOTHER ROUND OF ACCUMULATING
SNOW TOMORROW AND TOMORROW NIGHT.
&&
.NEAR TERM /THROUGH MONDAY/...
COLDER CLOUD TOPS ON IR SATELLITE AND RUC 500MB VORTICITY HAVE
REMAINED IN LOCKSTEP THROUGH THE DAY...AND THE WAVE IS NOW ENTERING
WESTERN PENNSYLVANIA. VISIBILITIES AT AUTOMATED SITES CONTINUE TO
RISE BEHIND THE WAVE...AND THIS SHOULD ALLOW FOR SNOW TO DIMINISH IN
COVERAGE. HOWEVER...UPSLOPE SNOW REMAINS LIKELY WITH WESTERLY WINDS
PICKING UP BEHIND THE SHORTWAVE. EVEN THOUGH ACCUMULATING SNOW WILL
CONTINUE IN THE WV/MD RIDGES...ADDITIONAL SNOW SHOULD NOT BE ENOUGH
TO EXTEND THE ADVISORY...BUT WILL LET IT RUN THROUGH ITS EXPIRATION
TIME.
FOCUS WILL THEN TURN TO LOW PRESSURE SYSTEM THAT WILL BE OVER
NORTHEASTERN MISSOURI TOMORROW MORNING AND MOVE EAST-SOUTHEAST INTO
SOUTHERN OHIO BY LATE MONDAY AFTERNOON. GENERAL TRENDS WITH THIS
SYSTEM OVER THE LAST 1-2 MODEL RUNS HAVE BEEN TO TRACK SLIGHTLY
FASTER AND STRONGER. PRIMARY CONCERN WITH THE SYSTEM WILL NOT BE
LONG DURATION SNOWFALL...BUT A QUICK BURST OF SNOW FOR A SHORT
PERIOD OF TIME. NAM/GFS SHOW STRONG OMEGA VALUES IN THE DENDRITIC
GROWTH ZONE...BUT ONLY FOR A COUPLE OF HOURS. HAVE GONE AHEAD AND
ISSUED ADVISORIES AND WARNINGS GENERALLY ALONG INTERSTATE 70 AND
SOUTH.
&&
.SHORT TERM /MONDAY NIGHT THROUGH WEDNESDAY/...
LOW PRESSURE WILL CONTINUE TO RUSH TO THE SOUTHEAST. AGAIN...THINK
THAT MODERATE SNOW IS POSSIBLE DURING THE EVENING HOURS WHILE THE
SYNOPTIC SYSTEM IS STILL IN THE AREA. WITH THE ADDITIONAL UPSLOPE
FLOW IN THE MOUNTAINS...HAVE SPECIFICALLY MENTIONED HEAVY SNOW FOR
GARRETT...PRESTON...AND TUCKER COUNTIES. SNOWFALL WILL BEGIN TO
DIMINISH AS THE SYNOPTIC SYSTEM CLEARS THE REGION...AND THINK THAT
NEARLY ALL SNOWFALL WILL COME TO AN END BY TUESDAY MORNING. WITH
WINDS LESS THAN 5KTS...NOT MUCH SUPPORT FOR UPSLOPE FLOW BEHIND THE
SYSTEM. AS HAS BEEN THE RECENT TREND...THAT MEANS IT WILL BE TIME
FOR THE NEXT SYSTEM TO IMPACT THE REGION. THIS LOW PRESSURE SYSTEM
WILL BE ACROSS UPPER MICHIGAN TUESDAY NIGHT AND REACH LAKE ONTARIO
BY WEDNESDAY MORNING...SO IT WILL BE ANOTHER QUICK MOVING SYSTEM.
HAVE ONLY INSERTED A SMALL AREA OF LIKELY POPS NORTH OF INTERSTATE
80...WITH CHANCE POPS FOR THE REST OF THE AREA. WITH THE LOW CENTER
FARTHER FROM THE REGION...ADDITIONAL SNOWFALL IS EXPECTED TO BE LOW.
EVEN THOUGH WINDS WILL BE FAVORABLE FOR UPSLOPE ON WEDNESDAY AFTER
THE LOW DEPARTS...LOW INVERSION HEIGHTS SHOULD ONLY ALLOW FOR A
DUSTING OF SNOW DURING THE DAYTIME. ALTHOUGH TEMPERATURES WILL RISE
A FEW NOTCHES ON TUESDAY AND WEDNESDAY...VALUES WILL REMAIN BELOW
SEASONAL NORMS.
&&
.LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY/...
MDLS ARE IN AGRMNT IN DEPICTIONS OF FLATTENED FLOW OVR THE CONUS
BY MID WEEK...AND IN DVLPMNT OF A CUTOFF LOW OVR THE SW U.S. BY
THE WEEKEND. THE PTN WL RESULT IN TEMP MODERATION FOR THE
REGION...CUMULATING IN A WEEKEND PROG ABOUT 10 DEGREES ABOVE THE
SEASONAL AVERAGES AS HTS RISE WITH EWD PROGRESS OF THE WRN STATES
LOW.
FOR POPS...A SHRTWV WITHIN THE ZONAL FLOW IS CURRENTLY TIMED TO
SPREAD PCPN OVR THE REGION FOR THURSDAY NGT AND EARLY FRIDAY. CHC
NMBRS WERE FORECAST GIVEN TIMING AND TROF-MAGNITUDE ISSUES...BUT
PROGRESSION LKS TO BE SUFFICIENTLY RAPID TO FORECAST A DRY WEEKEND.
&&
.AVIATION /21Z SUNDAY THROUGH FRIDAY/...
MVFR TO IFR WITH -SN AND STRATOCU CAN BE EXPECTED THIS AFTN AS
LOW PRES SLIDES ACRS THE UPR OH VALLEY REGION. SFC WIND WL VEER TO
THE WEST THIS AFTN FOLLOWING PASSAGE OF THE SFC TROF...AND IMPROVEMENT
IS ANTICIPATED AS SNOW DIMINISHES WITH INCRSG SBSDNC THIS EVE.
MORE RESTRICTIONS...INCLUDING WIDESPREAD IFR...ARE ANTICIPATED ON
MONDAY AS ANOTHER LOW IS FORECAST TO SPREAD SN OVR THE REGION.
.OUTLOOK.../SUNDAY NIGHT THROUGH THURSDAY/...
A SERIES OF DISTURBANCES WILL MAINTAIN PERIODIC RESTRICTIONS IN
SNOW SHOWERS AND STRATOCU THROUGH MIDWEEK.
&&
.PBZ WATCHES/WARNINGS/ADVISORIES...
MD...WINTER WEATHER ADVISORY UNTIL 7 PM EST THIS EVENING FOR MDZ001.
WINTER STORM WARNING FROM 2 PM MONDAY TO 10 AM EST TUESDAY FOR
MDZ001.
OH...WINTER WEATHER ADVISORY FROM 11 AM MONDAY TO 4 AM EST TUESDAY
FOR OHZ057>059-068-069.
PA...WINTER WEATHER ADVISORY FROM 2 PM MONDAY TO 6 AM EST TUESDAY
FOR PAZ031-074>076.
WINTER WEATHER ADVISORY UNTIL 7 PM EST THIS EVENING FOR PAZ074-
076.
WV...WINTER WEATHER ADVISORY FROM 2 PM MONDAY TO 6 AM EST TUESDAY
FOR WVZ021-022.
WINTER WEATHER ADVISORY FROM 11 AM MONDAY TO 4 AM EST TUESDAY
FOR WVZ003-004-012.
WINTER WEATHER ADVISORY UNTIL 7 PM EST THIS EVENING FOR WVZ023-
041.
WINTER STORM WARNING FROM 2 PM MONDAY TO 10 AM EST TUESDAY FOR
WVZ023-041.
&&
$$
AREA FORECAST DISCUSSION
NWS BALTIMORE MD/WASHINGTON DC
320 PM EST SUN FEB 3 2013
.SYNOPSIS...
AN UPPER LEVEL DISTURBANCE WILL MOVE EAST OF THE AREA BY THIS
EVENING...FOLLOWED BY HIGH PRESSURE THROUGH MONDAY. ANOTHER CLIPPER
LOW PRESSURE SYSTEM WILL ARRIVE LATE MONDAY NIGHT...MOVING OFF THE
COAST OVERNIGHT. A WEAK COLD FRONT WILL MOVE ACROSS THE AREA ON
TUESDAY NIGHT...WITH HIGH PRESSURE BUILDING IN WEDNESDAY AND
THURSDAY. ANOTHER LOW PRESSURE SYSTEM WILL ARRIVE BY FRIDAY.
&&
.NEAR TERM /THROUGH TONIGHT/...
SCATTERED SNOW SHOWER ACTIVITY WAS FOUND ACROSS MOST OF THE CWA
TODAY IN RESPONSE TO AN UPPER LEVEL WAVE COMING IN FROM THE WEST.
EARLIER TODAY...THE MULTIPLE SNOW BANDS FORMED IN RESPONSE TO
CONDITIONAL SYMMETRIC INSTABILITY...CSI...AS EVIDENT IN MODEL
CROSS SECTIONS OF WEAK NEGATIVE SATURATED GEOSTROPHIC EQUIVALENT
POTENTIAL VORTICITY...EPV. FORTUNATELY...MOISTURE WAS LIMITED AND
TEMPERATURES WERE NOT ALL THAT COLD AT THE SURFACE...SO WHAT
LITTLE SNOW THAT FELL DID NOT PRODUCE AN APPRECIABLE ACCUMULATION
OTHER THAN A DUSTING ON MAINLY GRASSY AREAS.
RADAR STILL HAS LIGHT ECHO RETURNS INDICATING POCKETS OF LIGHT
SNOW AND/OR FLURRIES. THE 12Z HIRES 4KM NCEP WRF-NMM MODEL PICKED
UP ON THIS SNOW ACTIVITY QUITE WELL FOR THIS AFTERNOON...AS HAS
THE 3KM HRRR MODEL. TIMING OF THE WAVE ON SATL MEANS THAT MOST OF
THE SCATTERED -SN ACTIVITY WILL BE MOVING EAST OF THE AREA BY 00Z/
MON...SAVE FOR CONTINUED UPSLOPE SNOW COMPONENT FOR THE WESTERN
SLOPE AREAS. ANY ACCUMULATIONS OF SNOW WILL BE LIMITED TO THE WRN
UPSLOPE AREA THIS EVENING WITH SEVERAL INCHES EXPECTED OVERNIGHT
AND BELOW CRITERIA FOR ANY WINTER HEADLINE. ELSEWHERE IN THE
CWA...ANY ACCUMULATION FOR THIS AFTERNOONS SNOW SHOWER ACTIVITY
COULD PERHAPS LEAVE A QUICK DUSTING OR COATING OF SNOW...LESS ONE
QUARTER OF AN INCH...AT WORST...WITH THE BULK OF ANY SNOW MELTING
QUICKLY DUE TO A COMBINATION OF BOUNDARY LAYER TEMPS BEING AT OR
ABOVE FREEZING AND SOME SOLAR INSULATION THAT IS MAKING IT THROUGH
BREAKS IN CLOUDS.
WINDS KICK UP BEHIND THE WAVE PASSAGE THIS EVENING FROM THE WEST.
THESE WINDS WILL ALSO HAVE A DRYING AFFECT ON THE ATMOSPHERE AND
CLOUDS SHOULD BE LESS PREVALENT...WITH AREAS EAST OF THE BLUE
RIDGE CLEARING OUT OVERNIGHT. TEMPS OVERNIGHT WERE BASED MAINLY ON
THE BIAS-CORRECTED ADJUSTED MET GUIDANCE.
ONE CONCERN COMING INTO THE SHIFT WAS FOR WIND CHILL POTENTIAL
MAINLY FOR THE FAR WESTERN AREAS. AFTER POPULATING THE GRIDS...CAN
ONLY FIND A FEW WIND CHILL TEMPS OVERNIGHT IN THE EXTREME WRN 5
ZNS THAT ARE BELOW ZERO...A FEW GRID POINTS REACH ABOUT -5 FOR AN
HOUR OR TWO OVERNIGHT...BUT COVERAGE DOES NOT WARRANT ANY WIND
CHILL ADVISORY HEADLINE AT THE MOMENT.
&&
.SHORT TERM /MONDAY/...
THE DAY STARTS OFF FAIRLY QUIET AS WEAK HIGH PRES TO OUR SOUTH
CONTINUES TO SLIDE EAST AND OFFSHORE BY MID AFTERNOON...IN
RESPONSE TO THE NEXT CLIPPER LOW PRESSURE SYSTEM HEADING OUR WAY.
AT 18Z/MON...GUIDANCE SHOW THE CENTER OF THE CLIPPER TO BE OVER
IL/IN AND BY 00Z/TUE OVER THE OH VALLEY. ASIDE FROM SOME UPSLOPE
SNOW SHOWER ACTIVITY IN THE WRN 5 ZNS...MOST OF THE CWA WILL BE
DRY FOR THE BETTER PART OF THE DAY. HAVE BROUGHT CHC POPS INTO THE
NW THIRD OF THE CWA AFTER 18Z...AND THERE COULD BE SOME SNOW
FALLING THE NW PORTION OF THE CWA AFTER 20Z. ANY ACCUMULATIONS
BEFORE 22Z IN THE NW PORTION SHOULD BE A HALF INCH OR LESS.
TEMPS FOR MON WERE BASED ON THE BIAS CORRECTED ADJSTD MAV/GFS
GUIDANCE.
&&
.LONG TERM /MONDAY NIGHT THROUGH SUNDAY/...
THE UPPER VORT MAX THAT WILL BE SLIDING ACROSS THE REGION LATE
MONDAY WILL BE FAIRLY POTENT IN A RELATIVELY SMALL AREA. THE FEATURE
ITSELF WILL DRIFT OVER THE MD/PA BORDER...WRAPPING PRECIP TIGHTLY
AROUND IT. A BULK OF THE PRECIP - ALL SNOW - WILL MOVE ACROSS THE
NRN HALF OF THE CWA BUT THE ENTIRE REGION WILL HAVE AT LEAST A LOW
CHANCE OF SNOW SHOWERS BEFORE THE VORT MAX MOVES OFF THE COAST.
THOUGH ANOTHER WEAK CLIPPER SYSTEM WILL PASS OVER THE REGION THE
NEXT NIGHT AS WELL...THE MON NIGHT CLIPPER WILL HAVE THE BETTER
CHANCES FOR WIDESPREAD SNOW - ALBEIT LIGHT E OF THE MTNS. PRECIP
WILL QUICKLY EXIT THE AREA OVERNIGHT AND OFF THE COAST BY THE
PREDAWN HRS TUE.
UNLIKE THE OTHER CLIPPER SYSTEMS IN THE PARADE OF THESE FEATURES
OVER THE PAST FEW DAYS...WINDS BEHIND THIS SYSTEM WILL BE MUCH
LIGHTER AND ACTUALLY TURN TOWARD SLY - NOT AS DRY. DEWPOINTS WILL
INCREASE OVERNIGHT AND INTO TUE...ALLOWING FOR TEMPS TO INCREASE AT
LEAST TOWARD FREEZING BY MID AFTN...IF NOT A FEW DEGREES ABOVE. EACH
FOLLOWING DAY HEADING INTO THE LATTER PART OF THE WEEK WILL BE
PROGRESSIVELY WARMER...AS HIGH PRESSURE SLOWLY BEGINS TO TAKE OVER
THE REGION FROM THE SOUTHWEST.
THE LONGWAVE UPPER TROUGH THAT BROUGHT THE PAST FEW DAYS OF
CLIPPERS...INTERMITTENT SNOWS...WINDS AND COLD TEMPS WILL FINALLY
BEGIN TO DRIFT OFF TO THE NE. AT LEAST THE INFLUENCE FROM THIS
LARGE-SCALE FEATURE WILL MOVE AWAY FROM THE REGION AND ALLOW WARMER
WX TO BUILD BACK TOWARD THE NORTH. MED/LONG RANGE GUIDANCE STILL
DIVERGING W/ THE FRI LOW PRESSURE SYSTEM...BUT IN AGREEMENT THAT A
SHORTWAVE FROM THE GREAT LAKES WILL MEET UP W/ ONE FROM THE
SOUTHEAST - OVER THE EAST COAST ON FRI AND POSSIBLY BRING MORE
PRECIP TO THE AREA...AT THIS POINT MORE LIQUID THAN FROZEN PRECIP.
THEN...LIKELY A QUIET AND WARMER WEEKEND THAN THE CURRENT OR
PREVIOUS ONE.
&&
.AVIATION /19Z SUNDAY THROUGH FRIDAY/...
SCATTERED -SHSN ACTIVITY HAS BEEN A BIT TRICKY TO DEAL WITH FOR
THE TAFS. RADAR SUGGESTS THAT ANOTHER ROUND OF SOME FLURRIES LIGHT
SNOW COULD MOVE THROUGH THE REGION THROUGH THE LATE AFTERNOON HOURS.
RADAR IS ALSO SHOWING ISOLATED BANDS OF SNOW OVER THE SHENANDOAH
VALLEY...AND THEY COULD IMPACT THE DC/MRB/BALT TERMINALS UNTIL 23Z
PRODUCING SOME BRIEF IFR CIGS/VSBYS. EXPECT CLEARING TRENDS AFTER
00Z IN THE DC/BALT TAFS. WINDS SHOULD ALSO KICK UP FROM THE SW TO
W THIS EVENING WITH SOME GUSTS UP TO 18-20KT.
FOR MON...EXPECTING MAINLY VFR THROUGH MOST OF THE DAY AHEAD OF
THE NEXT CLIPPER.
ONE LAST CLIPPER SYSTEM W/ SNOW CHANCES ON MON NIGHT...POSSIBLY
SPREADING ANOTHER BRIEF PERIOD OF LIGHT SNOW ACROSS THE AREA INTO
THE OVERNIGHT HRS...BUT QUICKLY EXITING BY DAWN TUE MRNG. WINDS WILL
REMAIN LIGHT BEHIND THE SYSTEM...THEN A MAINLY DRY COLD FRONT WILL
SWING THRU THE AREA TUE NIGHT. ONLY LIGHT NLY WINDS BEHIND THIS
SYSTEM ON WED...THEN MORE QUIET WX INTO THU. ANOTHER LOW PRESSURE
SYSTEM EXPECTED FOR FRIDAY. THEN HIGH PRESSURE FOR THE COMING
WEEKEND.
&&
.MARINE...
WILL RAISE THE SCA UP AT 5 PM FOR MAINLY THE LOWER TIDAL POTOMAC
AND THE ENTIRE MD PORTION OF THE CHES BAY. THE MORE SIGNIFICANT
SCA WINDS GUSTS MIGHT HOLD OF AN HOUR OR TWO AFTER 5 PM...BUT ONCE
THE UPPER WAVE PASSES...THEY SHOULD KICK IN.
WILL CONTINUE THE SCA FOR THE AFOREMENTIONED MARINE AREAS ON MON
AS THE HIGH PRES BUILDS OVER THE SE STATES...BUT THE PRESSURE
GRADIENT WILL RELAX DURING THE AFTERNOON AS THE NEXT CLIPPER
SYSTEM HEADS EAST.
ANOTHER CLIPPER SYSTEM WILL MOVE THRU THE AREA LATE MON AND OFF THE
COAST BY EARLY TUE. A WEAK COLD FRONT THE NEXT NIGHT...BUT WINDS
WILL REMAIN LARGELY WELL BELOW SCA CRITERIA FOR THE REMAINDER OF THE
WEEK.
&&
.LWX WATCHES/WARNINGS/ADVISORIES...
DC...NONE.
MD...WINTER STORM WATCH FROM MONDAY EVENING THROUGH TUESDAY MORNING
FOR MDZ501.
VA...WINTER STORM WATCH FROM MONDAY EVENING THROUGH TUESDAY MORNING
FOR VAZ503.
WV...WINTER STORM WATCH FROM MONDAY EVENING THROUGH TUESDAY MORNING
FOR WVZ501-503-505.
MARINE...SMALL CRAFT ADVISORY FROM 5 PM THIS AFTERNOON TO 3 PM EST
MONDAY FOR ANZ530>534-537>543.
&&
$$
SYNOPSIS...SMZ/GMS
NEAR TERM...SMZ
SHORT TERM...SMZ
LONG TERM...GMS
AVIATION...SMZ/GMS
MARINE...SMZ/GMS
AREA FORECAST DISCUSSION
NWS PITTSBURGH PA
1249 PM EST SUN FEB 3 2013
.SYNOPSIS...
AN UNSETTLED PATTERN WITH PERIODS OF SNOW AND COLD TEMPERATURES
WILL CONTINUE THROUGH TUESDAY.
&&
.NEAR TERM /THROUGH TONIGHT/...
WITH 1245PM UPDATE...MADE SOME MINOR TWEAKS TO HOURLY
TEMPERATURES...BUT REST OF FORECAST APPEARS ON TRACK.
INFRARED SATELLITE IMAGE OF COLDER CLOUD TOPS ALIGN NICELY WITH
THE UPPER LEVEL SHORTWAVE DEPICTED BY THE RUC MODEL. AS OF
10AM...THIS FEATURE IS ACROSS WESTERN AND CENTRAL OHIO...AND IT
WILL SLOWLY MOVE EAST THROUGH THE DAY. WITH 10AM UPDATE...PRIMARY
CHANGE WAS TO BRING LIKELY POPS A LITTLE BIT FARTHER WEST INTO THE
NORTHERN WV PANHANDLE AND EASTERN OHIO...CONSIDERING RECENT RADAR
TRENDS. ALSO MADE SOME MINOR CHANGES TO TEMPERATURES (LOWERING
THEM SLIGHTLY) AND SNOWFALL (BUMPING SOME LOCATIONS UP A FEW
TENTHS OF AN INCH).
NEXT SHORTWAVE IN THE SERIES WILL CROSS THE OHIO VALLEY TODAY AND
EXIT TONIGHT. THIS CLIPPER TYPE SYSTEM IS MORE STRETCHED ALOFT
AND LESS ORGANIZED THAN SATURDAY SYSTEM...AND AROUND AN INCH OF
SNOW EXPECTED MOST LOCATIONS EXCEPT FOR THE RIDGES WHERE SOME
UPSLOPE ENHANCEMENT IN THE HIGHEST ELEVATIONS WILL ALLOW FOR 2-4
TODAY AND ANOTHER 1-2 TONIGHT IN PRESTON...TUCKER AND GARRETT
WHERE ADVISORY REMAINS IN PLACE. 1 TO 3 ADDITIONAL INCHES FOR THE
CHESTNUT AND LAURELS IN WESTMORELAND AND FAYETTE TODAY INTO THE
EVENING. TEMPERATURES WILL BE A TIGHT RANGE TODAY MAINLY IN THE
20S.
SURFACE RIDGE AXIS WILL BRING AN END TO THE SNOW OVERNIGHT AS IT
QUICKLY PASSES EAST OF THE APPALACHIANS. LOWS IN THE TEENS WITH A
FEW SINGLE DIGITS RIDGES. HOW QUICKLY WIND FIELDS WEAKEN WILL
DETERMINE HOW LOW WIND CHILL VALUES CAN GET. -10F OR COLDER
POSSIBLE ACROSS PRESTON...TUCKER AND GARRET AND MENTIONED IN
FORECAST BUT WILL HOLD OFF ON ADVISORY.
&&
.SHORT TERM /MONDAY THROUGH TUESDAY/...
MODELS NOW IN GENERAL AGREEMENT ON NEXT CLIPPER BEING BETTER
ORGANIZED WITH A WARM ADVECTION REGIME AHEAD OF IT SPREADING SNOW
INTO EASTERN OHIO BY MIDDAY MONDAY AND SPREADING ACROSS THE
ENTIRE REGION MONDAY AFTERNOON. SNOW WILL CONTINUE MONDAY NIGHT
THEN DIMINISH TUESDAY MORNING WITH THIS SYSTEM. WITH THE
ASSOCIATED SURFACE LOW TO TRACK SOUTH OF THE MASON DIXON LINE A
SWATH OF 2-4 INCH SNOW POSSIBLE SOUTH OF PITTSBURGH WITH 6 OR MORE
POSSIBLE IN THE HIGHER TERRAIN OF PRESTON...TUCKER AND GARRETT. AS
SUCH COORDINATED A WINTER STORM WATCH FROM MONDAY AFTERNOON INTO
TUESDAY MORNING FOR THESE COUNTIES. FROM PITTSBURGH NORTH 1 TO 3
INCHES POSSIBLE.
TEMPERATURES MONDAY MAINLY IN THE 20S. TEMPERATURES WILL DROP OFF
INTO THE TEENS LATE MONDAY NIGHT AS SYSTEM PASSES.
THE FUN IS NOT OVER HOWEVER...AS YET ANOTHER SHORTWAVE WILL BE
MOVING IN QUICKLY TUESDAY ON THE HEELS OF DEPARTING SYSTEM. THIS
SYSTEM WILL BRING LIGHT SNOW BACK INTO REGION BY TUESDAY
AFTERNOON. MODELS ARE NOT IN AGREEMENT ON TRACK WITH NAM FARTHER
NORTH THAN THE ECMWF. FOR NOW CHANCE POPS AS THIS WILL BE FURTHER
DEFINED IN LATER FORECASTS. NOT AS COLD TUESDAY WITH HIGH FROM THE
MID 20S NORTH TO LOWER 30S SOUTH.
&&
.LONG TERM /TUESDAY NIGHT THROUGH SATURDAY/...
MDLS ARE IN AGRMNT IN DEPICTIONS OF FLATTENED FLOW OVR THE CONUS
BY MID WEEK...AND IN DVLPMNT OF A CUTOFF LOW OVR THE SW U.S. BY
THE WEEKEND. THE PTN WL RESULT IN TEMP MODERATION FOR THE
REGION...CUMULATING IN A WEEKEND PROG ABOUT 10 DEGREES ABOVE THE
SEASONAL AVERAGES AS HTS RISE WITH EWD PROGRESS OF THE WRN STATES
LOW.
FOR POPS...A SHRTWV WITHIN THE ZONAL FLOW IS CURRENTLY TIMED TO
SPREAD PCPN OVR THE REGION FOR THURSDAY NGT AND EARLY FRIDAY. CHC
NMBRS WERE FORECAST GIVEN TIMING AND TROF-MAGNITUDE ISSUES...BUT
PROGRESSION LKS TO BE SUFFICIENTLY RAPID TO FORECAST A DRY WEEKEND.
&&
.AVIATION /18Z SUNDAY THROUGH FRIDAY/...
MVFR TO IFR WITH -SN AND STRATOCU CAN BE EXPECTED THIS AFTN AS
LOW PRES SLIDES ACRS THE UPR OH VALLEY REGION. SFC WIND WL VEER TO
THE WEST THIS AFTN FOLLOWING PASSAGE OF THE SFC TROF...AND IMPROVEMENT
IS ANTICIPATED AS SNOW DIMINISHES WITH INCRSG SBSDNC THIS EVE.
MORE RESTRICTIONS...INCLUDING WIDESPREAD IFR...ARE ANTICIPATED ON
MONDAY AS ANOTHER LOW IS FORECAST TO SPREAD SN OVR THE REGION.
.OUTLOOK.../SUNDAY NIGHT THROUGH THURSDAY/...
A SERIES OF DISTURBANCES WILL MAINTAIN PERIODIC RESTRICTIONS IN
SNOW SHOWERS AND STRATOCU THROUGH MIDWEEK.
&&
.PBZ WATCHES/WARNINGS/ADVISORIES...
MD...WINTER WEATHER ADVISORY UNTIL 7 PM EST THIS EVENING FOR MDZ001.
WINTER STORM WATCH FROM MONDAY AFTERNOON THROUGH TUESDAY
MORNING FOR MDZ001.
OH...NONE.
PA...WINTER WEATHER ADVISORY UNTIL 7 PM EST THIS EVENING FOR PAZ074-
076.
WV...WINTER WEATHER ADVISORY UNTIL 7 PM EST THIS EVENING FOR WVZ023-
041.
WINTER STORM WATCH FROM MONDAY AFTERNOON THROUGH TUESDAY
MORNING FOR WVZ023-041.
&&
$$
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
402 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 18Z TAFS THROUGH 18Z MONDAY AFTERNOON)
ISSUED AT 1232 PM EST SUN FEB 3 2013
KCMX...EXPECT IFR CONDITIONS TO DOMINATE THIS FCST PERIOD WITH NW
FLOW OF ARCTIC AIR ALLOWING CONTINUED LES. LIFR CONDITIONS WL BE
COMMON INTO THIS EVNG WITH STRONGER NW WINDS ALLOWING MORE BLOWING
OF THE FINE SN FLAKES...WHICH WL BE EFFECTIVE AT REDUCING VSBY. AS
THE WINDS DIMINISH A BIT TNGT...SO WL THE BLSN/POTENTIAL FOR LIFR
VSBYS.
KIWD...IFR VSBYS WITH FALLING SN/BLSN WL TEND TO GIVE WAY TO MVFR
CONDITIONS BY THIS EVNG AS THE THE LLVL FLOW SLOWLY BACKS AND
WEAKENS...WHICH WL DIMINISH THE SHSN AND BLSN.
KSAW...ALTHOUGH PASSING -SHSN COULD BRING MVFR VSBY/CIGS AT
TIMES...EXPECT VFR CONDITIONS TO PREDOMINATE THIS FCST PERIOD WITH
DOWNSLOPE 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 FROM 7 PM THIS EVENING TO 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...KC
MARINE...KC/JLA
AREA FORECAST DISCUSSION
NWS GRAND RAPIDS MI
336 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 18Z TAFS THROUGH 18Z MONDAY)
ISSUED AT 1220 PM EST SUN FEB 3 2013
MVFR/IFR CONDITIONS ARE ANTICIPATED THIS AFTERNOON AS LIGHT LAKE
EFFECT SNOW SHOWERS CONTINUE. THE SNOW SHOWERS SHOULD TAPER OFF LATE
THIS AFTERNOON AND EVENING BUT ANOTHER CLIPPER SYSTEM WILL BRING
ANOTHER ROUND OF SNOW LATE TONIGHT THROUGH MONDAY MORNING WHICH WILL
RESULT IN CONTINUED MVFR TO IFR CONDITIONS THROUGH 18Z MON.
&&
.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...LAURENS
HYDROLOGY...OSTUNO
MARINE...OSTUNO
AREA FORECAST DISCUSSION...UPDATED
NWS ST LOUIS MO
1211 PM CST SUN FEB 3 2013
.UPDATE...
ISSUED AT 1210 PM CST SUN FEB 3 2013
UPDATED FORECAST AS CLOUDS HAVE ABOUT CLEARED OUT OF FORECAST
AREA. HIGH TEMPS WILL BE HARD TO PIN DOWN IN SOME LOCATIONS DUE TO
FRESH NEW SNOW COVER DESPITE THE SUNNY SKIES. FOR NOW HAVE HIGHS
IN THE LOW TO MID 30S FOR NORTHEAST HALF OF FORECAST AREA...WITH
UPPER 30S TO UPPER 40S FOR AREAS SOUTHWEST OF NEW SNOW FIELD. WINDS
TO DIMINISH TOWARDS THIS EVENING AS SURFACE RIDGE BUILDS IN.
BYRD
&&
.SHORT TERM...
ISSUED AT 330 AM CST SUN FEB 3 2013
(TODAY THROUGH TUESDAY)
THANKS TO A COMPACT AND POTENT NW FLOW VORT MAX...SOME RATHER
IMPRESSIVE LOW LEVEL FORCING AND A POCKET OF STEEP MID LEVEL LAPSE
RATES...A NICE BAND OF 2-4 INCHES OF SNOW FELL LAST NIGHT WITH THE
HIGHEST AMOUNTS CENTERED RIGHT THROUGH THE ST LOUIS METRO. KUDOS
TO THE SAT AFTERNOON RUNS OF THE HRRR WHICH WAS THE SOLE MODEL
THAT COMPLETELY NAILED THE SNOWFALL FORECAST. THE SNOW HAS LONG
ENDED AND THE ASSOCIATED SURFACE FRONTAL SYSTEM WAS PASSING THRU
FAR ERN MO AT THIS TIME. GOOD CAA IS EXPECTED THIS MORNING IN THE
WAKE OF THE COLD FRONT WITH STRATUS IN THE LOW LEVEL NW FLOW FROM
ERN MO INTO IL. CAA SHOULD CEASE BY MIDDAY AS THE SURFACE RIDGE
SHIFTS INTO THE AREA WITH WEAK WAA DEVELOPING DURING THE AFTERNOON
IN CENTRAL MO AS THE SURFACE RIDGE CONTINUES TO DEPART TO THE
EAST. IN RESPONSE THE CLOUDS SHOULD ALSO EXIT EASTWARD.
SOUTHERLY WINDS WILL BECOME ESTABLISHED ACROSS THE AREA THIS
EVENING IN THE WAKE OF THE DEPARTING HIGH AND IN ADVANCE OF THE
NEXT COLD FRONTAL SYSTEM...WITH STRONG LOW LEVEL WAA ENSUING
DURING THE LATE EVENING AND OVERNIGHT HOURS. THIS FLOW REGIME
COMBINED WITH INCREASING AND THICKENING CLOUDS OVERNIGHT WOULD
SUPPORT MIN TEMPS OCCURING DURING THE EVENING AND THEN RISING
OVERNIGHT. THE SNOW COVER COULD BE PROBLEMATIC IF THE SURFACE WINDS
REMAIN LIGHTER THAN EXPECTED...ALLOWING FOR A GREATER EVENING TEMP
FALL THAN CURRENTLY FCST. ATTM IT APPEARS THAT SHOWERS SHOULD
DEVELOP ACROSS ERN OK DURING THE OVERNIGHT HOURS AND SPREAD NEWD
ACROSS SE MO AND SRN IL BETWEEN 15-18Z MONDAY IN RESPONSE TO
INCREASING LARGE SCALE ASCENT AND STRONG LOW LEVEL MOISTURE
TRANSPORT/CONVERGENCE. GIVEN THE WAA REGIME AND EXPECTED ONSET OF
PCPN...SURFACE TEMPERATURES ARE EXPECTED TO BE ABOVE FREEZING AND
CONTINUE TO WARM THROUGH THE MORNING AHEAD OF THE FRONT...ALTHOUGH
THAT WARMING COULD BE RETARDED A BIT BY DIABATIC COOLING. STRONG
CAA IS EXPECTED IN THE WAKE OF THE COLD FRONT DRIVING SEWD THRU
THE MORNING AND EARLY AFTERNOON. HIGH PRESSURE WILL THEN BUILD
INTO THE AREA ON MONDAY NIGHT AND THEN YET ANOTHER NW FLOW SHORT
WAVE WILL BRING A WEAK FRONT THROUGH THE REGION ON TUESDAY.
GLASS
&&
.LONG TERM...
ISSUED AT 330 AM CST SUN FEB 3 2013
(WEDNESDAY THROUGH SATURDAY)
A BIG PATTERN CHANGE WILL EVOLVE DURING THIS PERIOD AS THE BROAD
LONG WAVE TROF THAT HAS BEEN SENDING US THE PARADE OF NW FLOW
SHORT WAVES FINALLY DEPARTS WELL INTO THE ATLANTIC. HEIGHTS ALOFT
RISE IN RESPONSE...WITH THE FLOW ALOFT BECOMING QUASI-ZONAL THRU
THE NATIONS MIDSECTION WITH EMBEDDED LOW AMPLITUDE SHORT WAVES. ONE
OF THESE WAVES WILL BRING ANOTHER COLD FRONT THROUGH ON THURSDAY
WITH AN ACCOMPANING CHANCE OF SHOWERS. THE FLOW ALOFT CONTINUES TO
EVOLVE THROUGH LATE WEEK WITH THE DEVELOPMENT OF A DEEP WRN TROF.
CURRENT INDICATIONS ARE THAT THIS TROF MAY BRING A THREAT OF
SHOWERS AND THUNDERSTORMS BY LATE NEXT WEEKEND AS AN INITIAL WAVE
MIGRATES INTO THE CENTRAL U.S.. OVERALL THE EXTENDED PERIOD SHOULD
BE MARKED BY ABOVE AVERAGE TEMPERATURES.
GLASS
&&
.AVIATION...
ISSUED AT 1210 PM CST SUN FEB 3 2013
CLOUDS HAVE MOVED OUT OF TAF SITES...SO MAIN ISSUE IN THE SHORT
TERM IS THE GUSTY NORTHWEST WINDS. SURFACE RIDGE IS QUICKLY
BUILDING IN...SO WINDS TO DIMINISH...BECOMING LIGHT AND VARIABLE
BY LATE THIS AFTERNOON...THEN VEER TO THE SOUTH AND PICKUP A BIT AS
RIDGE MOVES OFF TO OUR EAST BY MID EVENING. ALL OF THIS IS AHEAD
OF NEXT WEATHER SYSTEM THAT WILL SLIDE THROUGH AFTER 12Z
MONDAY...EXITING TAF SITES BY 18Z MONDAY. WINDS TO VEER TO THE
SOUTHWEST THEN WEST TO NORTHWEST BEHIND THE COLD FRONT AND PICKUP
TO AROUND 15KTS. AS FOR CLOUDS...JUST EXPECT MID AND HIGH
CLOUDS...THOUGH SOME MVFR SC POSSIBLE...ESPECIALLY OVER KUIN...AS
IT WILL BE CLOSER TO SURFACE LOW.
SPECIFICS FOR KSTL...CLOUDS HAVE MOVED OUT OF METRO AREA...SO MAIN
ISSUE IN THE SHORT TERM IS THE GUSTY NORTHWEST WINDS. SURFACE
RIDGE IS QUICKLY BUILDING IN...SO WINDS TO DIMINISH...BECOMING
LIGHT AND VARIABLE BY 23Z...THEN VEER TO THE SOUTH AND PICKUP A BIT
AS RIDGE MOVES OFF TO OUR EAST BY 03Z MONDAY. ALL OF THIS IS
AHEAD OF NEXT WEATHER SYSTEM THAT WILL SLIDE THROUGH KSTL BY 17Z
MONDAY. WINDS TO VEER TO THE SOUTHWEST THEN WEST TO NORTHWEST
BEHIND THE COLD FRONT AND PICKUP TO AROUND 15KTS. AS FOR
CLOUDS...JUST EXPECT MID AND HIGH CLOUDS.
BYRD
&&
.LSX WATCHES/WARNINGS/ADVISORIES...
MO...NONE.
IL...NONE.
&&
$$
WFO LSX
AREA FORECAST DISCUSSION
NWS SIOUX FALLS SD
1130 AM CST SUN FEB 3 2013
.DISCUSSION.../ISSUED AT 1010 AM CST/
SET UP SIMILAR TO YESTERDAY AT THIS TIME WITH A WARM FRONT SITTING
OVER OUR SOUTHWESTERN CWA AND A SHORTWAVE DROPPING SOUTHWARD THROUGH
NORTH DAKOTA. DIFFERENCE FROM YESTERDAY IS THAT MOST OF OUR CWA WILL
NOT EXPERIENCE ANY SNOW WITH THIS SHORTWAVE...BEING CONFINED TO OUR
FAR NORTHEASTERN MINNESOTA ZONES. OVERALL FORECAST LOOKS TO BE ON
TRACK...THOUGH DID INCREASE POPS A LITTLE EARLIER IN OUR NORTHEAST
WITH CURRENT RADAR SHOWING A BAND OF LIGHT SNOW ALREADY MOVING OUT
OF EASTERN NORTH DAKOTA. THE RAP AND GEM REGIONAL MODELS COVER THIS
TIMING THE BEST...BRINGING THE POSSIBILITY OF LIGHT SNOW INTO OUR
EXTREME NORTHEAST BETWEEN THE 18Z TO 21Z TIME FRAME. UPDATES OUT.
/JM
&&
.AVIATION.../FOR THE 18Z TAF ISSUANCE/
VFR CONDITIONS EXPECTED FOR MOST OF THE AREA TODAY WITH SOME HIGH
CLOUDINESS STREAMING ACROSS THE REGION. THE EXCEPTION WILL BE OVER
PORTIONS OF SOUTHWESTERN MINNESOTA WHERE LOWER CLOUDS WILL RESIDE
WITH A POSSIBILITY OF LIGHT SNOW DEVELOPING IN THE LATE AFTERNOON.
STRATUS LOOKS TO RETURN TO THE AREA TONIGHT...WITH NORTHERLY WINDS
PICKING UP AFTER 04Z. WINDS WILL THEN BEGIN TO SUBSIDE BY MONDAY
MORNING...THOUGH STRATUS MAY LINGER.
&&
.PREV DISCUSSION.../ISSUED AT 420 AM CST/
SURFACE HIGH PRESSURE WILL SLIDE SOUTHEAST ACROSS THE REGION TODAY
WHILE A QUASISTATIONARY BOUNDARY NEAR THE MISSOURI VALLEY WILL
ADVANCE SLOWLY EAST THROUGH THE DAY AS WARM FRONT. THIS WILL SET UP
A RELATIVELY MILD DAY FOR THE MAJORITY OF THE FORECAST AREA WITH
LIGHT WINDS TURNING SOUTHERLY. A BAND OF MID LEVEL STRATUS WILL
TRACK ALONG THIS BOUNDARY THIS MORNING BUT SHOULD SHIFT INTO OUR
EASTERN HALF AND THIN BY THIS AFTERNOON. COPIOUS SUNSHINE AND WARM
AIR ADVECTION SHOULD ALLOW FOR HIGHS NEAR 50 TODAY IN SOUTH CENTRAL
SOUTH DAKOTA. ELSEWHERE...MUCH OF SOUTHEAST SOUTH DAKOTA AND
NORTHWEST IOWA WILL BE NEAR OR ABOVE FREEZING FOR HIGHS. WARMING
WILL BE MORE OF STRUGGLE IN MINNESOTA AHEAD OF THE BOUNDARY WHERE
CLOUDS WILL BE A BIT MORE PREVALENT AND HIGHS WILL BE CLOSER TO THE
MID OR UPPER 20S.
MID LEVEL CLIPPER SHORTWAVE DIVES SOUTHEAST THROUGH THE NORTHERN
PLAINS THIS AFTERNOON AND SHOULD GLANCE OUR NORTHEASTERN HALF THIS
EVENING AND OVERNIGHT. UPPER LEVEL FORCING MOVES INTO THE REGION
OVERNIGHT AND SHOULD BE ENOUGH TO PRODUCE SOME LIGHT SNOW NEAR THE
WEAK BOUNDARY. THE BEST POTENTIAL WILL BE NEAR THE BUFFALO RIDGE AND
JUST OUTSIDE OUR FORECAST AREA WHERE MOISTURE PROFILES LOOK BEST.
HAVE BUMPED UP POPS TO 90+ IN OUR EXTREME NORTHEAST. MOISTURE IS
PRETTY LIMITED WITH THIS FAST MOVING SYSTEM...BUT IT LOOKS LIKE A
QUICK INCH OF SNOW IS REASONABLE NEAR THE BUFFALO RIDGE AREA. EXPECT
STRATUS TO BUILD THROUGH THE REGION OVERNIGHT...WHICH MAY BRING SOME
ADDITIONAL FLURRY ACTIVITY LATE TONIGHT. TEMPERATURES WILL BE TRICKY
AS WINDS TURN NORTHERLY BEHIND THIS SYSTEM AND MIGHT BE SLIGHTLY
BREEZY. WITH STRATUS IN PLACE...STAYED A BIT WARMER THAN GUIDANCE.
LOW STRATUS IS LIKELY TO STICK AROUND INTO MUCH OF MONDAY WITH
PRETTY WEAK FLOW LOCKED IN FOR THE BETTER PART OF THE DAY. IT DOES
NOT APPEAR THAT THERE WILL BE A SIGNIFICANT PUSH OF COLD AIR BEHIND
THE DEPARTING SYSTEM...BUT IT SHOULD BE ENOUGH WITH THE CLOUDY SKIES
TO COOL HIGHS AROUND 10 DEGREES FROM HIGHS TODAY. THE NEXT CLIPPER
QUICKLY DIVES INTO THE UPPER MIDWEST ON MONDAY NIGHT. A WARM FRONTAL
BOUNDARY IS EXPECTED TO ADVANCE ACROSS THE FORECAST AREA...MAKING
FOR A TRICKY TEMPERATURE FORECAST OVERNIGHT. SHOULD SEE READINGS
SLOWLY CLIMB OVERNIGHT. WITH THE CRUX OF THIS SYSTEM PASSING OUTSIDE
OF THE CWA...EXPECT ONLY SLIGHT CHANCE OR CHANCE OF LIGHT SNOW
MAINLY AFTER MIDNIGHT IN SOUTHWEST MINNESOTA.
QUIETER WEATHER PATTERN SETS UP MID WEEK WITH A MORE ZONAL FLOW
DEVELOPING BY WEDNESDAY. TEMPERATURES WILL BE ON A WARMING TREND FOR
TUESDAY AND WEDNESDAY WITH MOSTLY CLEAR SKIES. SOME THIN HIGH CLOUDS
DO DEVELOP FOR WEDNESDAY BUT WITH SOUTHEAST WINDS TURNING A BIT MORE
SOUTH TO SOUTHWEST BY AFTERNOON...TEMPERATURES ARE EXPECTED TO BE
MILD IN THE MID 30S TO UPPER 40S ACROSS THE FORECAST AREA. HEDGED
SLIGHTLY WARMER THAN THE ALLBLEND HERE WITH THE ECMWF EVEN
SUGGESTING THAT 50 WILL BE POSSIBLE IN THE MISSOURI VALLEY.
MODELS IN DECENT AGREEMENT IN KICKING A SHORTWAVE THROUGH THE AREA
LATE WEDNESDAY WITH A DRY FRONTAL PASSAGE AND NO REAL COLD AIR
EXPECTED IN ITS WAKE. DRY NORTHWEST FLOW QUICKLY SETS UP ON THURSDAY
BUT IS REPLACED BY A SHIFT TO STRONG SOUTHERLY FLOW FOR FRIDAY AS
THE UPPER LEVEL RIDGE HEADS SHIFTS INTO THE MISSISSIPPI VALLEY. BOTH
DAYS CONTINUE THE MILD AND DRY CONDITIONS. DECENT MODEL AGREEMENT
GOES ASKEW FOR THE WEEKEND IN REGARDS TO A VERY LARGE TROUGH OVER
THE INTERMOUNTAIN WEST. THE ECMWF IS THE MOST PROGRESSIVE WITH THIS
FEATURE WHICH ARRIVES IN THE WESTERN PLAINS AS EARLY AS LATE FRIDAY
NIGHT. THE GFS IS QUITE A BIT SLOWER...DEEPER AND FURTHER SOUTH WITH
THIS SYSTEM WITH THE MAIN IMPACT DELAYED UNTIL SATURDAY NIGHT.
DECIDED TO NOT ADJUST THE ALLBLEND POPS GIVEN A GREAT DEAL OF TIMING
UNCERTAINTY. THIS PAINTS HIGH END CHANCES THROUGHOUT THE CWA FOR
SATURDAY AND SATURDAY NIGHT. PRECIPITATION TYPE WILL ALSO BE A
CONCERN WITH TEMPERATURES NEAR FREEZING AND WHAT LOOKS LIKE A PRETTY
WARM SYSTEM MOVING IN. INITIALLY COULD SEE SOME LIGHT FREEZING RAIN
OR RAIN WHICH WILL GRADUALLY TRANSITION TO SNOW SATURDAY NIGHT.
&&
.FSD WATCHES/WARNINGS/ADVISORIES...
IA...NONE.
MN...NONE.
NE...NONE.
SD...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS SIOUX FALLS SD
1010 AM CST SUN FEB 3 2013
.DISCUSSION...
SET UP SIMILAR TO YESTERDAY AT THIS TIME WITH A WARM FRONT SITTING
OVER OUR SOUTHWESTERN CWA AND A SHORTWAVE DROPPING SOUTHWARD THROUGH
NORTH DAKOTA. DIFFERENCE FROM YESTERDAY IS THAT MOST OF OUR CWA WILL
NOT EXPERIENCE ANY SNOW WITH THIS SHORTWAVE...BEING CONFINED TO OUR
FAR NORTHEASTERN MINNESOTA ZONES. OVERALL FORECAST LOOKS TO BE ON
TRACK...THOUGH DID INCREASE POPS A LITTLE EARLIER IN OUR NORTHEAST
WITH CURRENT RADAR SHOWING A BAND OF LIGHT SNOW ALREADY MOVING OUT
OF EASTERN NORTH DAKOTA. THE RAP AND GEM REGIONAL MODELS COVER THIS
TIMING THE BEST...BRINGING THE POSSIBILITY OF LIGHT SNOW INTO OUR
EXTREME NORTHEAST BETWEEN THE 18Z TO 21Z TIME FRAME. UPDATES OUT.
/JM
&&
.PREV DISCUSSION.../ISSUED AT 420 AM CST/
SURFACE HIGH PRESSURE WILL SLIDE SOUTHEAST ACROSS THE REGION TODAY
WHILE A QUASISTATIONARY BOUNDARY NEAR THE MISSOURI VALLEY WILL
ADVANCE SLOWLY EAST THROUGH THE DAY AS WARM FRONT. THIS WILL SET UP
A RELATIVELY MILD DAY FOR THE MAJORITY OF THE FORECAST AREA WITH
LIGHT WINDS TURNING SOUTHERLY. A BAND OF MID LEVEL STRATUS WILL
TRACK ALONG THIS BOUNDARY THIS MORNING BUT SHOULD SHIFT INTO OUR
EASTERN HALF AND THIN BY THIS AFTERNOON. COPIOUS SUNSHINE AND WARM
AIR ADVECTION SHOULD ALLOW FOR HIGHS NEAR 50 TODAY IN SOUTH CENTRAL
SOUTH DAKOTA. ELSEWHERE...MUCH OF SOUTHEAST SOUTH DAKOTA AND
NORTHWEST IOWA WILL BE NEAR OR ABOVE FREEZING FOR HIGHS. WARMING
WILL BE MORE OF STRUGGLE IN MINNESOTA AHEAD OF THE BOUNDARY WHERE
CLOUDS WILL BE A BIT MORE PREVALENT AND HIGHS WILL BE CLOSER TO THE
MID OR UPPER 20S.
MID LEVEL CLIPPER SHORTWAVE DIVES SOUTHEAST THROUGH THE NORTHERN
PLAINS THIS AFTERNOON AND SHOULD GLANCE OUR NORTHEASTERN HALF THIS
EVENING AND OVERNIGHT. UPPER LEVEL FORCING MOVES INTO THE REGION
OVERNIGHT AND SHOULD BE ENOUGH TO PRODUCE SOME LIGHT SNOW NEAR THE
WEAK BOUNDARY. THE BEST POTENTIAL WILL BE NEAR THE BUFFALO RIDGE AND
JUST OUTSIDE OUR FORECAST AREA WHERE MOISTURE PROFILES LOOK BEST.
HAVE BUMPED UP POPS TO 90+ IN OUR EXTREME NORTHEAST. MOISTURE IS
PRETTY LIMITED WITH THIS FAST MOVING SYSTEM...BUT IT LOOKS LIKE A
QUICK INCH OF SNOW IS REASONABLE NEAR THE BUFFALO RIDGE AREA. EXPECT
STRATUS TO BUILD THROUGH THE REGION OVERNIGHT...WHICH MAY BRING SOME
ADDITIONAL FLURRY ACTIVITY LATE TONIGHT. TEMPERATURES WILL BE TRICKY
AS WINDS TURN NORTHERLY BEHIND THIS SYSTEM AND MIGHT BE SLIGHTLY
BREEZY. WITH STRATUS IN PLACE...STAYED A BIT WARMER THAN GUIDANCE.
LOW STRATUS IS LIKELY TO STICK AROUND INTO MUCH OF MONDAY WITH
PRETTY WEAK FLOW LOCKED IN FOR THE BETTER PART OF THE DAY. IT DOES
NOT APPEAR THAT THERE WILL BE A SIGNIFICANT PUSH OF COLD AIR BEHIND
THE DEPARTING SYSTEM...BUT IT SHOULD BE ENOUGH WITH THE CLOUDY SKIES
TO COOL HIGHS AROUND 10 DEGREES FROM HIGHS TODAY. THE NEXT CLIPPER
QUICKLY DIVES INTO THE UPPER MIDWEST ON MONDAY NIGHT. A WARM FRONTAL
BOUNDARY IS EXPECTED TO ADVANCE ACROSS THE FORECAST AREA...MAKING
FOR A TRICKY TEMPERATURE FORECAST OVERNIGHT. SHOULD SEE READINGS
SLOWLY CLIMB OVERNIGHT. WITH THE CRUX OF THIS SYSTEM PASSING OUTSIDE
OF THE CWA...EXPECT ONLY SLIGHT CHANCE OR CHANCE OF LIGHT SNOW
MAINLY AFTER MIDNIGHT IN SOUTHWEST MINNESOTA.
QUIETER WEATHER PATTERN SETS UP MID WEEK WITH A MORE ZONAL FLOW
DEVELOPING BY WEDNESDAY. TEMPERATURES WILL BE ON A WARMING TREND FOR
TUESDAY AND WEDNESDAY WITH MOSTLY CLEAR SKIES. SOME THIN HIGH CLOUDS
DO DEVELOP FOR WEDNESDAY BUT WITH SOUTHEAST WINDS TURNING A BIT MORE
SOUTH TO SOUTHWEST BY AFTERNOON...TEMPERATURES ARE EXPECTED TO BE
MILD IN THE MID 30S TO UPPER 40S ACROSS THE FORECAST AREA. HEDGED
SLIGHTLY WARMER THAN THE ALLBLEND HERE WITH THE ECMWF EVEN
SUGGESTING THAT 50 WILL BE POSSIBLE IN THE MISSOURI VALLEY.
MODELS IN DECENT AGREEMENT IN KICKING A SHORTWAVE THROUGH THE AREA
LATE WEDNESDAY WITH A DRY FRONTAL PASSAGE AND NO REAL COLD AIR
EXPECTED IN ITS WAKE. DRY NORTHWEST FLOW QUICKLY SETS UP ON THURSDAY
BUT IS REPLACED BY A SHIFT TO STRONG SOUTHERLY FLOW FOR FRIDAY AS
THE UPPER LEVEL RIDGE HEADS SHIFTS INTO THE MISSISSIPPI VALLEY. BOTH
DAYS CONTINUE THE MILD AND DRY CONDITIONS. DECENT MODEL AGREEMENT
GOES ASKEW FOR THE WEEKEND IN REGARDS TO A VERY LARGE TROUGH OVER
THE INTERMOUNTAIN WEST. THE ECMWF IS THE MOST PROGRESSIVE WITH THIS
FEATURE WHICH ARRIVES IN THE WESTERN PLAINS AS EARLY AS LATE FRIDAY
NIGHT. THE GFS IS QUITE A BIT SLOWER...DEEPER AND FURTHER SOUTH WITH
THIS SYSTEM WITH THE MAIN IMPACT DELAYED UNTIL SATURDAY NIGHT.
DECIDED TO NOT ADJUST THE ALLBLEND POPS GIVEN A GREAT DEAL OF TIMING
UNCERTAINTY. THIS PAINTS HIGH END CHANCES THROUGHOUT THE CWA FOR
SATURDAY AND SATURDAY NIGHT. PRECIPITATION TYPE WILL ALSO BE A
CONCERN WITH TEMPERATURES NEAR FREEZING AND WHAT LOOKS LIKE A PRETTY
WARM SYSTEM MOVING IN. INITIALLY COULD SEE SOME LIGHT FREEZING RAIN
OR RAIN WHICH WILL GRADUALLY TRANSITION TO SNOW SATURDAY NIGHT.
&&
.AVIATION.../FOR THE 12Z TAF ISSUANCE/
FOR MOST OF THE AREA INCLUDING TAF SITES VFR SHOULD CONTINUE THROUGH
04/06Z WITH VARYING CLOUDS AND SOME CEILINGS AOA 6K FEET. FOR THE
AREA FROM BKX TO MJQ AND NORTHEAST...OR MOSTLY IN SOUTHWEST MN...VFR
THROUGH 22Z WILL BE FOLLOWED BY INCREASING AREAS OF CEILINGS 1-3K
FEET AND VISIBILITIES 3-5SM IN SNOW 22Z-04/01Z...THEN AREAS OF IFR
VISIBILITIES BLO 3SM AFTER 04/01Z. 04/06Z-12Z SNOW IN THIS AREA WILL
DECREASE BUT CEILINGS 1-3K FEET WILL CONTINUE AND SPREAD SOUTH OVER
THE REST OF THE AREA.
&&
.FSD WATCHES/WARNINGS/ADVISORIES...
IA...NONE.
MN...NONE.
NE...NONE.
SD...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
230 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 18Z MONDAY
1126 AM CST SUN FEB 3 2013
SNOW WILL DEVELOP AT KRST AROUND 03.22Z AND AT KLSE AROUND 04.01Z.
ONCE THIS OCCURS...CEILINGS WILL BECOME MVFR AND VISIBILITIES WILL
DROP TO AROUND 1 MILE. THE SNOW WILL THEN DISSIPATE AROUND 04.13Z
AT KRST AND AROUND 04.14Z AT KLSE. SNOW TOTALS WILL RANGE FROM 2
TO 4 INCHES WITH SOME LOCALIZED 5 INCH AMOUNTS POSSIBLE.
IN THE WAKE OF THIS SYSTEM...EXPECT BOTH CEILING AND VISIBILITIES
TO RAPIDLY BECOME VFR.
&&
.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.....BOYNE