Forecast Discussions mentioning any of
"HRRR" "RAP" "RR" "RUC13" "RUC" received at GSD on 11/30/13
AREA FORECAST DISCUSSION
NWS ALBANY NY
631 AM EST THU NOV 28 2013
.SYNOPSIS...
LOW PRESSURE WILL CONTINUE TO DEEPEN AND INTENSIFY AS IT MOVES
FURTHER NORTHEAST INTO THE CANADIAN MARITIMES...AS HIGH PRESSURE
WILL ATTEMPT TO BUILD IN FROM THE SOUTHEAST. BLUSTERY AND COLD
CONDITIONS ARE EXPECTED FOR THANKSGIVING TODAY WITH SOME LAKE
EFFECT SNOW SHOWERS WEST OF THE GREATER CAPITAL REGION. A WEAK
DISTURBANCE WILL BRING SOME LAKE EFFECT SNOW SHOWERS AND FLURRIES
TONIGHT INTO EARLY FRIDAY MAINLY WEST OF THE HUDSON RIVER
VALLEY...BEFORE HIGH PRESSURE BUILDS IN LATE FRIDAY INTO THE FIRST
HALF OF THE WEEKEND WITH DRY WEATHER AND BELOW NORMAL TEMPERATURES
TO CLOSE NOVEMBER.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 630 AM EST...HAPPY THANKSGIVING EVERYONE ! BLUSTERY AND COLD
CONDITIONS GREET ERN NY AND WRN NEW ENGLAND THIS MORNING...AS THE
UPPER TROUGH AXIS TO THE STRONG STORM SYSTEM YESTERDAY HAS CROSSED
THE REGION. THE CYCLONE IS NOW DEEPENING AND INTENSIFYING OVER
LABRADOR /980 HPA/. SOME GUSTY WINDS ARE IMPACTING PARTS OF THE REGION
WITH THE STRONG SFC PRESSURE GRADIENT BETWEEN THE DEPARTING
CYCLONE...AND HIGH PRESSURE OVER THE LOWER MS RIVER
VALLEY/SOUTHEAST. KALB HAD A PEAK WIND GUST OF 39 KTS /45 MPH/
BTWN 1-2 AM AND AT 5 AM. THE CORE OF THE STRONGEST WINDS AT H850 OF
40-50 KTS WILL BE OVER THE ERN HALF OF THE FCST AREA PRIOR TO 12Z.
SOME GUSTS OF 30-45 MPH WILL BE POSSIBLE ESPECIALLY PRIOR TO
NOON...AS THE SFC PRESSURE GRADIENT STARTS TO WEAKEN THEREAFTER.
THE STRONGEST GUSTS WILL BE DUE TO THE FUNNELING EFFECT DOWN THE
MOHAWK RIVER VALLEY.
THE CYCLONIC FLOW WILL CONTINUE WITH H850 TEMPS FALLING TO -18C TO
-13C FROM NORTHWEST TO SOUTHEAST OVER THE FCST AREA. IN THE W/NW
SOME MULTIBANDS OF LAKE EFFECT WILL CONTINUE TO BE POSSIBLE. THE
LATEST HRRR SHOWS A WEAKENING OF THE ACTIVITY AROUND 12Z. THE CURRENT
RADAR SHOWS SEVERAL NARROW MULTIBANDS OFF LAKE ONTARIO IMPACTING
THE WRN DACKS...W-CNTRL MOHAWK...AND NRN CATSKILLS. THESE BANDS
SEEM TO BE ENDURING SOME SHEAR AND DRY AIR INTRUDING. POPS WERE
ADJUSTED FOR MORE SNOW SHOWERS OVER THE NRN AND ERN CATSKILLS.
NONETHELESS...LOCALLY A BURST OF WIND DRIVEN SNOW IS POSSIBLE
ESPECIALLY ACROSS THE WRN DACKS...W-CNTRL MOHAWK VALLEY...AND THE
SRN GREENS/BERKS...DUE TO THE W/NW UPSLOPE COMPONENT. THE LAKE
EFFECT ADVISORY FOR SRN HERKIMER WILL CONTINUE...IT GOES ALL THE
WAY TO 7 AM TOMORROW. THE ACTIVITY MAY SLIP SOUTH OF THE ADVISORY
AREA LATER TODAY BASED ON THE HRRR...BUT THE LOCAL HIRES WRF SHOWS
A COUPLE OF BANDS IN THE 300 DEG TRAJECTORY BOUNDARY LAYER
FLOW...AND ONE DOES GO THROUGH SRN HERKIMER...MONTGOMERY AND WRN
FULTON COUNTIES INTO THE PM. BOTH FORMS OF HIGH RESOLUTION
GUIDANCE SHOWS THE BANDS WEAKENING IN THE AFTERNOON...UNTIL A
SHORT-WAVE ARRIVES TONIGHT FROM THE GREAT LAKES REGION.
COLD...WINDY...AND PARTLY CLOUDY CONDITIONS WILL PERSIST TODAY FOR A
LARGE PORTION OF THE AREA WITH HIGH TEMPS ABOUT 15 DEGREES BELOW
NORMAL. EXPECT HIGHS IN THE TEENS AND L20S OVER THE SRN
DACKS...SRN GREENS...AND ERN CATSKILLS. MID AND U20S WILL BE
COMMON ELSEWHERE...EXCEPT FOR A FEW L30S IN THE MID HUDSON
VALLEY...SRN TACONICS...AND LITCHFIELD CTY CT.
&&
.SHORT TERM /FRIDAY THROUGH SATURDAY NIGHT/...
TONIGHT...THE AFOREMENTIONED IMPULSE IN THE CYCLONIC FLOW WILL MOVE
ACROSS THE REGION WITH SOME LAKE ENHANCED SNOW SHOWERS AND
FLURRIES. THE BOUNDARY LAYER FLOW SHOULD BACK INITIALLY FOR A
270-280 DEG TRAJECTORY FOR PERHAPS THE CNTRL PORTION OF HERKIMER
AND SW HAMILTON COS TO GET A LITTLE SNOW...BEFORE VEERING AGAIN INTO
THE WRN-CNTRL MOHAWK VALLEY AND NRN CATSKILLS. ANOTHER FEW INCHES
OF SNOW WILL BE POSSIBLE IN THESE LOCATIONS...AND A 3-6" TALLY FOR
THE ADVISORY AREA LOOKS FINE. CLOUDS WILL INCREASE FOR THE BULK OF
THE REGION WITH PERHAPS SOME FLURRIES FROM THE CAPITAL REGION
EASTWARD. THE MID LEVEL VORT MAX/SHORT-WAVE SHOULD MOVE DOWNSTREAM
BY FRI MORNING WITH THE INVERSION HEIGHTS STARTING TO LOWER TO
SQUASH THE LAKE EFFECT ACTIVITY. A COLD NIGHT IS EXPECTED WITH
MAINLY TEENS FOR LOWS FOR THE REGION...EXCEPT SOME SINGLE DIGITS
FOR THE SRN ADIRONDACK REGION....AND SRN GREENS.
FRIDAY...THE BIG SHOPPING DAY LOOKS MAINLY DRY WITH THE LAKE EFFECT
SNOW SHOWERS AND FLURRIES DWINDLING WITH A STRONG SFC ANTICYCLONE
RIDGING IN FROM SE ONTARIO...AND THE ERN GREAT LAKES REGION. THE
BEST CHC OF A STRAY SNOW SHOWER WILL BE OVER THE W-CNTRL MOHAWK
RIVER VALLEY...AND NRN CATSKILLS. H850 TEMPS WILL STILL BE A
LITTLE BELOW NORMAL WITH -12C TO -15C READINGS. MAX TEMPS MAY BE A
SMIDGE WARMER THAN THANKSGIVING WITH HIGHS IN THE U20S TO L30S IN
THE VALLEYS /EXCEPT THE MID HUDSON RIVER VALLEY WHERE A FEW M30S
WILL BE POSSIBLE/...AND MAINLY LOWER TO M20S OVER THE HIGH PEAKS.
FRIDAY NIGHT...A VERY COLD NIGHT WILL BE ON TAP...AS THE SFC HIGH
STRENGTHENS TO 1043 HPA OVER ERN NY ON THE NAM40. MOSTLY
CLEAR/CLEAR SKIES WITH LIGHT TO CALM WINDS WILL YIELD IDEAL
RADIATIONAL COOLING CONDITIONS WITH LOWS FORECASTED CLOSER TO THE
NAM MOS GUIDANCE. LOWS 5 ABOVE TO 5 BELOW ZERO OVER THE LAKE
GEORGE REGION...AND SRN DACKS. SINGLE DIGITS IN THE MOHAWK RIVER
VALLEY...NRN CATSKILLS...HELDERBERGS...SRN VT...N-CNTRL BERKS...AND
NRN SARATOGA REGION...LOWER TEENS IN THE CAPITAL
DISTRICT..TACONICS...SRN BERKS...MID HUDSON VALLEY...AND NW CT.
SATURDAY-SATURDAY NIGHT...DRY WEATHER WILL START THE WEEKEND WITH
TEMPS STILL RUNNING BELOW NORMAL BY 10-15 DEGS. THE SFC HIGH MOVES
DOWN STREAM OVER NRN NEW ENGLAND AND THE GULF OF MAINE. A LIGHT
S/SE BREEZE BEGINS LATE IN THE DAY. MOSTLY SUNNY SKIES EARLY ON
WILL GIVE WAY TO INCREASE MID AND HIGH CLOUDS IN THE WARM
ADVECTION REGIME. A CLIPPER LOW WILL BE APPROACHING FROM THE NRN
GREAT LAKES REGION...AND S-CNTRL ONTARIO. THE TIMING IS VARIABLE
ON THE GUIDANCE...AND SLIGHT CHC OF SNOW SHOWERS WAS PLACED IN THE
GRIDS AFTER MIDNIGHT. LOWS SATURDAY WILL BE MUCH WARMER THAN THE
PREVIOUS NIGHTS WITH TEENS TO THE NORTH OF THE MOHAWK RIVER
VALLEY/CAPITAL REGION...AND LOWER TO M20S TO THE SOUTH.
&&
.LONG TERM /SUNDAY THROUGH WEDNESDAY/...
MUCH OF THE LONG TERM PERIOD IS EXPECTED TO BE DRY WITH THE MAIN
FEATURE FOR EARLY NEXT WEEK BEING A COASTAL LOW WHICH WOULD
POTENTIALLY IMPACT THE FA IN THE TUESDAY TO TUESDAY NIGHT TIME FRAME.
SUNDAY AND SUNDAY NIGHT...A CLIPPER TYPE SYSTEM WITH LIMITED
MOISTURE IS EXPECTED TO IMPACT THE FA AS IT TRACKS ACRS SRN CANADA
AND NRN NEW ENGLAND. HIGHS ON SUNDAY ARE EXPECTED TO RANGE FROM THE
LOWER 30S NORTHWEST TO MID 40S SOUTHEAST WITH LOWS SUNDAY NIGHT
GENERALLY IN THE 20S TO AROUND 30.
MONDAY AND MONDAY NIGHT...LOOK TO BE DRY AS HIGH PRESSURE BRIEFLY
BUILDS BACK INTO THE FA. HIGHS ARE EXPECTED TO BE IN THE 30S TO
AROUND 40 WITH SOME UPPER 20S ACROSS THE WESTERN ADIRONDACKS. LOWS
ARE EXPECTED TO BE IN THE MID TEENS TO UPPER 20S.
TUESDAY AND TUESDAY NIGHT...A COASTAL LOW MAY IMPACT THE FA AS IT
WORKS NORTHWARD UP THE EASTERN SEABOARD TUESDAY AND INTO THE GULF OF
MAINE BY LATE TUESDAY NIGHT. TOO FAR OUT TO GET VERY SPECIFIC AT THIS
POINT IN TIME...BUT WILL INCLUDE CHANCE POPS IN THE FORECAST FOR
NOW. EXPECT HIGHS ON TUESDAY IN THE UPPER 20S TO UPPER 30S WITH LOWS
TUESDAY NIGHT IN THE MID TEENS TO MID 20S.
WEDNESDAY...AT THIS TIME LOOKS TO BE A DRY DAY AS COASTAL SYSTEM
DEPARTS EAST OF THE CANADIAN MARITIMES AND A RIDGE OF HIGH PRESSURE
BUILDS SOUTHEAST FROM NORTH OF THE UPPER GREAT LAKES. EXPECT HIGHS
ON WEDNESDAY TO BE IN THE MID 20S TO UPPER 30S.
&&
.AVIATION /12Z THURSDAY THROUGH MONDAY/...
MAINLY VFR CONDITIONS ARE EXPECTED AT THE TAF SITES THROUGH THE
END OF THE TAF PERIOD ENDING AT 12Z FRI. SKIES WILL GENERALLY BE
SCT025-040 SCT100 TODAY EXCEPT FOR BRIEFLY OVC025 AT KPSF. SKIES
WILL BECOME SKC THIS EVENING.
THE WEST-NORTHWEST WINDS WILL REMAIN STRONG AS A STRONG PRESSURE
GRADIENT REMAINS ACRS THE REGION. WIND GUSTS WILL INCREASE TO
OVER 30 KTS AT TIMES. THE WINDS WILL GRADUALLY DIMINISH THU EVENING
BECOMING LIGHT AND VARIABLE AFTER DARK.
OUTLOOK...
FRIDAY TO SATURDAY: NO OPERATIONAL IMPACT. NO SIG WX.
SATURDAY NIGHT: LOW OPERATIONAL IMPACT. SLIGHT CHANCE OF SHSN.
SUNDAY: MODERATE OPERATIONAL IMPACT. CHANCE OF SHRA...SHSN.
SUNDAY NIGHT: LOW OPERATIONAL IMPACT. SLIGHT CHANCE OF SHSN.
MONDAY: LOW OPERATIONAL IMPACT. SLIGHT CHANCE OF SHRA...SHSN.
&&
.HYDROLOGY...
THE RIVERS HAVE CRESTED...AND FLOWS ARE STARTING TO DECREASE WITH
THE COLDER TEMPS. THE TREND THE NEXT 5 DAYS ARE FOR FLOWS TO
DECREASE IN THE COLD AND DRY AIR MASS INTO THE HOLIDAY WEEKEND.
ANY PRECIP WILL BE IN THE FORM OF SNOW SHOWERS PREDOMINANTLY WEST
OF THE HUDSON RIVER VALLEY TODAY INTO FRIDAY. A CLIPPER LOW MAY
BRING SOME SCT SNOW SHOWERS TO THE REGION TO CLOSE THE WEEKEND
WITH VERY LIGHT QPF. MOST LOCATIONS OUTSIDE OF THE FAVORED LAKE
EFFECT AREAS ARE NOT EXPECTED TO RECEIVE A TENTH OF AN INCH OF
LIQUID EQUIVALENT THE NEXT 5 DAYS.
FOR DETAILS ON SPECIFIC AREA RIVERS AND LAKES...INCLUDING OBSERVED
AND FORECAST RIVER STAGES AND LAKE ELEVATIONS...PLEASE VISIT THE
ADVANCED HYDROLOGIC PREDICTION SERVICE /AHPS/ GRAPHS ON OUR WEBSITE.
&&
.ALY WATCHES/WARNINGS/ADVISORIES...
CT...NONE.
NY...LAKE EFFECT SNOW ADVISORY UNTIL 7 AM EST FRIDAY FOR NYZ038.
MA...NONE.
VT...NONE.
&&
$$
SYNOPSIS...WASULA
NEAR TERM...WASULA
SHORT TERM...WASULA
LONG TERM...11
AVIATION...11
HYDROLOGY...JPV/WASULA
AREA FORECAST DISCUSSION
NWS ALBANY NY
609 AM EST THU NOV 28 2013
.SYNOPSIS...
LOW PRESSURE WILL CONTINUE TO DEEPEN AND INTENSIFY AS IT MOVES
FURTHER NORTHEAST INTO THE CANADIAN MARITIMES...AS HIGH PRESSURE
WILL ATTEMPT TO BUILD IN FROM THE SOUTHEAST. BLUSTERY AND COLD
CONDITIONS ARE EXPECTED FOR THANKSGIVING TODAY WITH SOME LAKE
EFFECT SNOW SHOWERS WEST OF THE GREATER CAPITAL REGION. A WEAK
DISTURBANCE WILL BRING SOME LAKE EFFECT SNOW SHOWERS AND FLURRIES
TONIGHT INTO EARLY FRIDAY MAINLY WEST OF THE HUDSON RIVER
VALLEY...BEFORE HIGH PRESSURE BUILDS IN LATE FRIDAY INTO THE FIRST
HALF OF THE WEEKEND WITH DRY WEATHER AND BELOW NORMAL TEMPERATURES
TO CLOSE NOVEMBER.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 330 AM EST...HAPPY THANKSGIVING EVERYONE ! BLUSTERY AND COLD
CONDITIONS GREET ERN NY AND WRN NEW ENGLAND THIS MORNING...AS THE
UPPER TROUGH AXIS TO THE STRONG STORM SYSTEM YESTERDAY HAS CROSSED
THE REGION. THE CYCLONE IS NOW DEEPENING AND INTENSIFYING OVER NEW
BRUNSWICK /984 HPA/. SOME GUSTY WINDS ARE IMPACTING PARTS OF THE
REGION WITH THE STRONG SFC PRESSURE GRADIENT BETWEEN THE DEPARTING
CYCLONE...AND HIGH PRESSURE OVER THE LOWER MS RIVER
VALLEY/SOUTHEAST. KALB HAD A PEAK WIND GUST OF 39 KTS /45 MPH/
BTWN 1-2 AM. THE CORE OF THE STRONGEST WINDS AT H850 OF 40-50 KTS
WILL BE OVER THE ERN HALF OF THE FCST AREA PRIOR TO 12Z. SOME
GUSTS OF 30-40 MPH WILL BE POSSIBLE ESPECIALLY PRIOR TO NOON...AS
THE SFC PRESSURE GRADIENT STARTS TO WEAKEN THEREAFTER.
THE CYCLONIC FLOW WILL CONTINUE WITH H850 TEMPS FALLING TO -18C TO
-13C FROM NORTHWEST TO SOUTHEAST OVER THE FCST AREA. IN THE W/NW
SOME MULTIBANDS OF LAKE EFFECT WILL CONTINUE TO BE POSSIBLE. THE
LATEST HRRR SHOWS A WEAKENING OF THE ACTIVITY TOWARDS 12Z. THE
CURRENT RADAR SHOWS SEVERAL NARROW MULTIBANDS OFF LAKE ONTARIO
IMPACTING THE WRN DACKS...W-CNTRL MOHAWK...AND NRN CATSKILLS.
THESE BANDS SEEM TO BE ENDURING SOME SHEAR AND DRY AIR INTRUDING.
NONETHELESS...LOCALLY A BURST OF WIND DRIVEN SNOW IS POSSIBLE
ESPECIALLY ACROSS THE WRN DACKS...W-CNTRL MOHAWK VALLEY...AND THE
SRN GREENS/BERKS...DUE TO THE W/NW UPSLOPE COMPONENT. THE LAKE
EFFECT ADVISORY FOR SRN HERKIMER WILL CONTINUE...IT GOES ALL THE
WAY TO 7 AM TOMORROW. THE ACTIVITY MAY SLIP SOUTH OF THE ADVISORY
AREA LATER TODAY BASED ON THE HRRR...BUT THE LOCAL HIRES WRF SHOWS
A COUPLE OF BANDS IN THE 300 DEG TRAJECTORY BOUNDARY LAYER
FLOW...AND ONE DOES GO THROUGH SRN HERKIMER...MONTGOMERY AND WRN
FULTON COUNTIES INTO THE PM. BOTH FORMS OF HIGH RESOLUTION
GUIDANCE SHOWS THE BANDS WEAKENING IN THE AFTERNOON...UNTIL A
SHORT-WAVE ARRIVES TONIGHT FROM THE GREAT LAKES REGION.
COLD...WINDY...AND PARTLY CLOUDY CONDITIONS WILL PERSIST TODAY FOR A
LARGE PORTION OF THE AREA WITH HIGH TEMPS ABOUT 15 DEGREES BELOW
NORMAL. EXPECT HIGHS IN THE TEENS AND L20S OVER THE SRN
DACKS...SRN GREENS...AND ERN CATSKILLS. MID AND U20S WILL BE
COMMON ELSEWHERE...EXCEPT FOR A FEW L30S IN THE MID HUDSON
VALLEY...SRN TACONICS...AND LITCHFIELD CTY CT.
&&
.SHORT TERM /FRIDAY THROUGH SATURDAY NIGHT/...
TONIGHT...THE AFOREMENTIONED IMPULSE IN THE CYCLONIC FLOW WILL MOVE
ACROSS THE REGION WITH SOME LAKE ENHANCED SNOW SHOWERS AND
FLURRIES. THE BOUNDARY LAYER FLOW SHOULD BACK INITIALLY FOR A
270-280 DEG TRAJECTORY FOR PERHAPS THE CNTRL PORTION OF HERKIMER
AND SW HAMILTON COS TO GET A LITTLE SNOW...BEFORE VEERING AGAIN INTO
THE WRN-CNTRL MOHAWK VALLEY AND NRN CATSKILLS. ANOTHER FEW INCHES
OF SNOW WILL BE POSSIBLE IN THESE LOCATIONS...AND A 3-6" TALLY FOR
THE ADVISORY AREA LOOKS FINE. CLOUDS WILL INCREASE FOR THE BULK OF
THE REGION WITH PERHAPS SOME FLURRIES FROM THE CAPITAL REGION
EASTWARD. THE MID LEVEL VORT MAX/SHORT-WAVE SHOULD MOVE DOWNSTREAM
BY FRI MORNING WITH THE INVERSION HEIGHTS STARTING TO LOWER TO
SQUASH THE LAKE EFFECT ACTIVITY. A COLD NIGHT IS EXPECTED WITH
MAINLY TEENS FOR LOWS FOR THE REGION...EXCEPT SOME SINGLE DIGITS
FOR THE SRN ADIRONDACK REGION....AND SRN GREENS.
FRIDAY...THE BIG SHOPPING DAY LOOKS MAINLY DRY WITH THE LAKE EFFECT
SNOW SHOWERS AND FLURRIES DWINDLING WITH A STRONG SFC ANTICYCLONE
RIDGING IN FROM SE ONTARIO...AND THE ERN GREAT LAKES REGION. THE
BEST CHC OF A STRAY SNOW SHOWER WILL BE OVER THE W-CNTRL MOHAWK
RIVER VALLEY...AND NRN CATSKILLS. H850 TEMPS WILL STILL BE A
LITTLE BELOW NORMAL WITH -12C TO -15C READINGS. MAX TEMPS MAY BE A
SMIDGE WARMER THAN THANKSGIVING WITH HIGHS IN THE U20S TO L30S IN
THE VALLEYS /EXCEPT THE MID HUDSON RIVER VALLEY WHERE A FEW M30S
WILL BE POSSIBLE/...AND MAINLY LOWER TO M20S OVER THE HIGH PEAKS.
FRIDAY NIGHT...A VERY COLD NIGHT WILL BE ON TAP...AS THE SFC HIGH
STRENGTHENS TO 1043 HPA OVER ERN NY ON THE NAM40. MOSTLY
CLEAR/CLEAR SKIES WITH LIGHT TO CALM WINDS WILL YIELD IDEAL
RADIATIONAL COOLING CONDITIONS WITH LOWS FORECASTED CLOSER TO THE
NAM MOS GUIDANCE. LOWS 5 ABOVE TO 5 BELOW ZERO OVER THE LAKE
GEORGE REGION...AND SRN DACKS. SINGLE DIGITS IN THE MOHAWK RIVER
VALLEY...NRN CATSKILLS...HELDERBERGS...SRN VT...N-CNTRL BERKS...AND
NRN SARATOGA REGION...LOWER TEENS IN THE CAPITAL
DISTRICT..TACONICS...SRN BERKS...MID HUDSON VALLEY...AND NW CT.
SATURDAY-SATURDAY NIGHT...DRY WEATHER WILL START THE WEEKEND WITH
TEMPS STILL RUNNING BELOW NORMAL BY 10-15 DEGS. THE SFC HIGH MOVES
DOWN STREAM OVER NRN NEW ENGLAND AND THE GULF OF MAINE. A LIGHT
S/SE BREEZE BEGINS LATE IN THE DAY. MOSTLY SUNNY SKIES EARLY ON
WILL GIVE WAY TO INCREASE MID AND HIGH CLOUDS IN THE WARM
ADVECTION REGIME. A CLIPPER LOW WILL BE APPROACHING FROM THE NRN
GREAT LAKES REGION...AND S-CNTRL ONTARIO. THE TIMING IS VARIABLE
ON THE GUIDANCE...AND SLIGHT CHC OF SNOW SHOWERS WAS PLACED IN THE
GRIDS AFTER MIDNIGHT. LOWS SATURDAY WILL BE MUCH WARMER THAN THE
PREVIOUS NIGHTS WITH TEENS TO THE NORTH OF THE MOHAWK RIVER
VALLEY/CAPITAL REGION...AND LOWER TO M20S TO THE SOUTH.
&&
.LONG TERM /SUNDAY THROUGH WEDNESDAY/...
MUCH OF THE LONG TERM PERIOD IS EXPECTED TO BE DRY WITH THE MAIN
FEATURE FOR EARLY NEXT WEEK BEING A COASTAL LOW WHICH WOULD
POTENTIALLY IMPACT THE FA IN THE TUESDAY TO TUESDAY NIGHT TIME FRAME.
SUNDAY AND SUNDAY NIGHT...A CLIPPER TYPE SYSTEM WITH LIMITED
MOISTURE IS EXPECTED TO IMPACT THE FA AS IT TRACKS ACRS SRN CANADA
AND NRN NEW ENGLAND. HIGHS ON SUNDAY ARE EXPECTED TO RANGE FROM THE
LOWER 30S NORTHWEST TO MID 40S SOUTHEAST WITH LOWS SUNDAY NIGHT
GENERALLY IN THE 20S TO AROUND 30.
MONDAY AND MONDAY NIGHT...LOOK TO BE DRY AS HIGH PRESSURE BRIEFLY
BUILDS BACK INTO THE FA. HIGHS ARE EXPECTED TO BE IN THE 30S TO
AROUND 40 WITH SOME UPPER 20S ACROSS THE WESTERN ADIRONDACKS. LOWS
ARE EXPECTED TO BE IN THE MID TEENS TO UPPER 20S.
TUESDAY AND TUESDAY NIGHT...A COASTAL LOW MAY IMPACT THE FA AS IT
WORKS NORTHWARD UP THE EASTERN SEABOARD TUESDAY AND INTO THE GULF OF
MAINE BY LATE TUESDAY NIGHT. TOO FAR OUT TO GET VERY SPECIFIC AT THIS
POINT IN TIME...BUT WILL INCLUDE CHANCE POPS IN THE FORECAST FOR
NOW. EXPECT HIGHS ON TUESDAY IN THE UPPER 20S TO UPPER 30S WITH LOWS
TUESDAY NIGHT IN THE MID TEENS TO MID 20S.
WEDNESDAY...AT THIS TIME LOOKS TO BE A DRY DAY AS COASTAL SYSTEM
DEPARTS EAST OF THE CANADIAN MARITIMES AND A RIDGE OF HIGH PRESSURE
BUILDS SOUTHEAST FROM NORTH OF THE UPPER GREAT LAKES. EXPECT HIGHS
ON WEDNESDAY TO BE IN THE MID 20S TO UPPER 30S.
&&
.AVIATION /11Z THURSDAY THROUGH MONDAY/...
MAINLY VFR CONDITIONS ARE EXPECTED AT THE TAF SITES THROUGH THE
END OF THE TAF PERIOD ENDING AT 12Z FRI. SKIES WILL GENERALLY BE
SCT025-040 SCT100 TODAY EXCEPT FOR BRIEFLY OVC025 AT KPSF. SKIES
WILL BECOME SKC THIS EVENING.
THE WEST-NORTHWEST WINDS WILL REMAIN STRONG AS A STRONG PRESSURE
GRADIENT REMAINS ACRS THE REGION. WIND GUSTS WILL INCREASE TO
OVER 30 KTS AT TIMES. THE WINDS WILL GRADUALLY DIMINISH THU EVENING
BECOMING LIGHT AND VARIABLE AFTER DARK.
OUTLOOK...
THURSDAY NIGHT: LOW OPERATIONAL IMPACT. SLIGHT CHANCE OF SHSN.
FRIDAY TO SATURDAY: NO OPERATIONAL IMPACT. NO SIG WX.
SATURDAY NIGHT: LOW OPERATIONAL IMPACT. SLIGHT CHANCE OF SHSN.
SUNDAY: MODERATE OPERATIONAL IMPACT. CHANCE OF SHRA...SHSN.
SUNDAY NIGHT: LOW OPERATIONAL IMPACT. SLIGHT CHANCE OF SHSN.
MONDAY: LOW OPERATIONAL IMPACT. SLIGHT CHANCE OF SHRA...SHSN.
&&
.HYDROLOGY...
THE RIVERS HAVE CRESTED...AND FLOWS ARE STARTING TO DECREASE WITH
THE COLDER TEMPS. THE TREND THE NEXT 5 DAYS ARE FOR FLOWS TO
DECREASE IN THE COLD AND DRY AIR MASS INTO THE HOLIDAY WEEKEND.
ANY PRECIP WILL BE IN THE FORM OF SNOW SHOWERS PREDOMINANTLY WEST
OF THE HUDSON RIVER VALLEY TODAY INTO FRIDAY. A CLIPPER LOW MAY
BRING SOME SCT SNOW SHOWERS TO THE REGION TO CLOSE THE WEEKEND
WITH VERY LIGHT QPF. MOST LOCATIONS OUTSIDE OF THE FAVORED LAKE
EFFECT AREAS ARE NOT EXPECTED TO RECEIVE A TENTH OF AN INCH OF
LIQUID EQUIVALENT THE NEXT 5 DAYS.
FOR DETAILS ON SPECIFIC AREA RIVERS AND LAKES...INCLUDING OBSERVED
AND FORECAST RIVER STAGES AND LAKE ELEVATIONS...PLEASE VISIT THE
ADVANCED HYDROLOGIC PREDICTION SERVICE /AHPS/ GRAPHS ON OUR WEBSITE.
&&
.ALY WATCHES/WARNINGS/ADVISORIES...
CT...NONE.
NY...LAKE EFFECT SNOW ADVISORY UNTIL 7 AM EST FRIDAY FOR NYZ038.
MA...NONE.
VT...NONE.
&&
$$
SYNOPSIS...WASULA
NEAR TERM...WASULA
SHORT TERM...WASULA
LONG TERM...11
AVIATION...11
HYDROLOGY...JPV/WASULA
AREA FORECAST DISCUSSION
NWS ALBANY NY
331 AM EST THU NOV 28 2013
.SYNOPSIS...
LOW PRESSURE WILL CONTINUE TO DEEPEN AND INTENSIFY AS IT MOVES
FURTHER NORTHEAST INTO THE CANADIAN MARITIMES...AS HIGH PRESSURE
WILL ATTEMPT TO BUILD IN FROM THE SOUTHEAST. BLUSTERY AND COLD
CONDITIONS ARE EXPECTED FOR THANKSGIVING TODAY WITH SOME LAKE
EFFECT SNOW SHOWERS WEST OF THE GREATER CAPITAL REGION. A WEAK
DISTURBANCE WILL BRING SOME LAKE EFFECT SNOW SHOWERS AND FLURRIES
TONIGHT INTO EARLY FRIDAY MAINLY WEST OF THE HUDSON RIVER
VALLEY...BEFORE HIGH PRESSURE BUILDS IN LATE FRIDAY INTO THE FIRST
HALF OF THE WEEKEND WITH DRY WEATHER AND BELOW NORMAL TEMPERATURES
TO CLOSE NOVEMBER.
&&
.NEAR TERM /THROUGH TODAY/...
AS OF 330 AM EST...HAPPY THANKSGIVING EVERYONE ! BLUSTERY AND COLD
CONDITIONS GREET ERN NY AND WRN NEW ENGLAND THIS MORNING...AS THE
UPPER TROUGH AXIS TO THE STRONG STORM SYSTEM YESTERDAY HAS CROSSED
THE REGION. THE CYCLONE IS NOW DEEPENING AND INTENSIFYING OVER NEW
BRUNSWICK /984 HPA/. SOME GUSTY WINDS ARE IMPACTING PARTS OF THE
REGION WITH THE STRONG SFC PRESSURE GRADIENT BETWEEN THE DEPARTING
CYCLONE...AND HIGH PRESSURE OVER THE LOWER MS RIVER
VALLEY/SOUTHEAST. KALB HAD A PEAK WIND GUST OF 39 KTS /45 MPH/
BTWN 1-2 AM. THE CORE OF THE STRONGEST WINDS AT H850 OF 40-50 KTS
WILL BE OVER THE ERN HALF OF THE FCST AREA PRIOR TO 12Z. SOME
GUSTS OF 30-40 MPH WILL BE POSSIBLE ESPECIALLY PRIOR TO NOON...AS
THE SFC PRESSURE GRADIENT STARTS TO WEAKEN THEREAFTER.
THE CYCLONIC FLOW WILL CONTINUE WITH H850 TEMPS FALLING TO -18C TO
-13C FROM NORTHWEST TO SOUTHEAST OVER THE FCST AREA. IN THE W/NW
SOME MULTIBANDS OF LAKE EFFECT WILL CONTINUE TO BE POSSIBLE. THE
LATEST HRRR SHOWS A WEAKENING OF THE ACTIVITY TOWARDS 12Z. THE
CURRENT RADAR SHOWS SEVERAL NARROW MULTIBANDS OFF LAKE ONTARIO
IMPACTING THE WRN DACKS...W-CNTRL MOHAWK...AND NRN CATSKILLS.
THESE BANDS SEEM TO BE ENDURING SOME SHEAR AND DRY AIR INTRUDING.
NONETHELESS...LOCALLY A BURST OF WIND DRIVEN SNOW IS POSSIBLE
ESPECIALLY ACROSS THE WRN DACKS...W-CNTRL MOHAWK VALLEY...AND THE
SRN GREENS/BERKS...DUE TO THE W/NW UPSLOPE COMPONENT. THE LAKE
EFFECT ADVISORY FOR SRN HERKIMER WILL CONTINUE...IT GOES ALL THE
WAY TO 7 AM TOMORROW. THE ACTIVITY MAY SLIP SOUTH OF THE ADVISORY
AREA LATER TODAY BASED ON THE HRRR...BUT THE LOCAL HIRES WRF SHOWS
A COUPLE OF BANDS IN THE 300 DEG TRAJECTORY BOUNDARY LAYER
FLOW...AND ONE DOES GO THROUGH SRN HERKIMER...MONTGOMERY AND WRN
FULTON COUNTIES INTO THE PM. BOTH FORMS OF HIGH RESOLUTION
GUIDANCE SHOWS THE BANDS WEAKENING IN THE AFTERNOON...UNTIL A
SHORT-WAVE ARRIVES TONIGHT FROM THE GREAT LAKES REGION.
COLD...WINDY...AND PARTLY CLOUDY CONDITIONS WILL PERSIST TODAY FOR A
LARGE PORTION OF THE AREA WITH HIGH TEMPS ABOUT 15 DEGREES BELOW
NORMAL. EXPECT HIGHS IN THE TEENS AND L20S OVER THE SRN
DACKS...SRN GREENS...AND ERN CATSKILLS. MID AND U20S WILL BE
COMMON ELSEWHERE...EXCEPT FOR A FEW L30S IN THE MID HUDSON
VALLEY...SRN TACONICS...AND LITCHFIELD CTY CT.
&&
.SHORT TERM /TONIGHT THROUGH SATURDAY NIGHT/...
TONIGHT...THE AFOREMENTIONED IMPULSE IN THE CYCLONIC FLOW WILL MOVE
ACROSS THE REGION WITH SOME LAKE ENHANCED SNOW SHOWERS AND
FLURRIES. THE BOUNDARY LAYER FLOW SHOULD BACK INITIALLY FOR A
270-280 DEG TRAJECTORY FOR PERHAPS THE CNTRL PORTION OF HERKIMER
AND SW HAMILTON COS TO GET A LITTLE SNOW...BEFORE VEERING AGAIN INTO
THE WRN-CNTRL MOHAWK VALLEY AND NRN CATSKILLS. ANOTHER FEW INCHES
OF SNOW WILL BE POSSIBLE IN THESE LOCATIONS...AND A 3-6" TALLY FOR
THE ADVISORY AREA LOOKS FINE. CLOUDS WILL INCREASE FOR THE BULK OF
THE REGION WITH PERHAPS SOME FLURRIES FROM THE CAPITAL REGION
EASTWARD. THE MID LEVEL VORT MAX/SHORT-WAVE SHOULD MOVE DOWNSTREAM
BY FRI MORNING WITH THE INVERSION HEIGHTS STARTING TO LOWER TO
SQUASH THE LAKE EFFECT ACTIVITY. A COLD NIGHT IS EXPECTED WITH
MAINLY TEENS FOR LOWS FOR THE REGION...EXCEPT SOME SINGLE DIGITS
FOR THE SRN ADIRONDACK REGION....AND SRN GREENS.
FRIDAY...THE BIG SHOPPING DAY LOOKS MAINLY DRY WITH THE LAKE EFFECT
SNOW SHOWERS AND FLURRIES DWINDLING WITH A STRONG SFC ANTICYCLONE
RIDGING IN FROM SE ONTARIO...AND THE ERN GREAT LAKES REGION. THE
BEST CHC OF A STRAY SNOW SHOWER WILL BE OVER THE W-CNTRL MOHAWK
RIVER VALLEY...AND NRN CATSKILLS. H850 TEMPS WILL STILL BE A
LITTLE BELOW NORMAL WITH -12C TO -15C READINGS. MAX TEMPS MAY BE A
SMIDGE WARMER THAN THANKSGIVING WITH HIGHS IN THE U20S TO L30S IN
THE VALLEYS /EXCEPT THE MID HUDSON RIVER VALLEY WHERE A FEW M30S
WILL BE POSSIBLE/...AND MAINLY LOWER TO M20S OVER THE HIGH PEAKS.
FRIDAY NIGHT...A VERY COLD NIGHT WILL BE ON TAP...AS THE SFC HIGH
STRENGTHENS TO 1043 HPA OVER ERN NY ON THE NAM40. MOSTLY
CLEAR/CLEAR SKIES WITH LIGHT TO CALM WINDS WILL YIELD IDEAL
RADIATIONAL COOLING CONDITIONS WITH LOWS FORECASTED CLOSER TO THE
NAM MOS GUIDANCE. LOWS 5 ABOVE TO 5 BELOW ZERO OVER THE LAKE
GEORGE REGION...AND SRN DACKS. SINGLE DIGITS IN THE MOHAWK RIVER
VALLEY...NRN CATSKILLS...HELDERBERGS...SRN VT...N-CNTRL BERKS...AND
NRN SARATOGA REGION...LOWER TEENS IN THE CAPITAL
DISTRICT..TACONICS...SRN BERKS...MID HUDSON VALLEY...AND NW CT.
SATURDAY-SATURDAY NIGHT...DRY WEATHER WILL START THE WEEKEND WITH
TEMPS STILL RUNNING BELOW NORMAL BY 10-15 DEGS. THE SFC HIGH MOVES
DOWN STREAM OVER NRN NEW ENGLAND AND THE GULF OF MAINE. A LIGHT
S/SE BREEZE BEGINS LATE IN THE DAY. MOSTLY SUNNY SKIES EARLY ON
WILL GIVE WAY TO INCREASE MID AND HIGH CLOUDS IN THE WARM
ADVECTION REGIME. A CLIPPER LOW WILL BE APPROACHING FROM THE NRN
GREAT LAKES REGION...AND S-CNTRL ONTARIO. THE TIMING IS VARIABLE
ON THE GUIDANCE...AND SLIGHT CHC OF SNOW SHOWERS WAS PLACED IN THE
GRIDS AFTER MIDNIGHT. LOWS SATURDAY WILL BE MUCH WARMER THAN THE
PREVIOUS NIGHTS WITH TEENS TO THE NORTH OF THE MOHAWK RIVER
VALLEY/CAPITAL REGION...AND LOWER TO M20S TO THE SOUTH.
&&
.LONG TERM /SUNDAY THROUGH WEDNESDAY/...
MUCH OF THE LONG TERM PERIOD IS EXPECTED TO BE DRY WITH THE MAIN
FEATURE FOR EARLY NEXT WEEK BEING A COASTAL LOW WHICH WOULD
POTENTIALLY IMPACT THE FA IN THE TUESDAY TO TUESDAY NIGHT TIME FRAME.
SUNDAY AND SUNDAY NIGHT...A CLIPPER TYPE SYSTEM WITH LIMITED
MOISTURE IS EXPECTED TO IMPACT THE FA AS IT TRACKS ACRS SRN CANADA
AND NRN NEW ENGLAND. HIGHS ON SUNDAY ARE EXPECTED TO RANGE FROM THE
LOWER 30S NORTHWEST TO MID 40S SOUTHEAST WITH LOWS SUNDAY NIGHT
GENERALLY IN THE 20S TO AROUND 30.
MONDAY AND MONDAY NIGHT...LOOK TO BE DRY AS HIGH PRESSURE BRIEFLY
BUILDS BACK INTO THE FA. HIGHS ARE EXPECTED TO BE IN THE 30S TO
AROUND 40 WITH SOME UPPER 20S ACROSS THE WESTERN ADIRONDACKS. LOWS
ARE EXPECTED TO BE IN THE MID TEENS TO UPPER 20S.
TUESDAY AND TUESDAY NIGHT...A COASTAL LOW MAY IMPACT THE FA AS IT
WORKS NORTHWARD UP THE EASTERN SEABOARD TUESDAY AND INTO THE GULF OF
MAINE BY LATE TUESDAY NIGHT. TOO FAR OUT TO GET VERY SPECIFIC AT THIS
POINT IN TIME...BUT WILL INCLUDE CHANCE POPS IN THE FORECAST FOR
NOW. EXPECT HIGHS ON TUESDAY IN THE UPPER 20S TO UPPER 30S WITH LOWS
TUESDAY NIGHT IN THE MID TEENS TO MID 20S.
WEDNESDAY...AT THIS TIME LOOKS TO BE A DRY DAY AS COASTAL SYSTEM
DEPARTS EAST OF THE CANADIAN MARITIMES AND A RIDGE OF HIGH PRESSURE
BUILDS SOUTHEAST FROM NORTH OF THE UPPER GREAT LAKES. EXPECT HIGHS
ON WEDNESDAY TO BE IN THE MID 20S TO UPPER 30S.
&&
.AVIATION /08Z THURSDAY THROUGH MONDAY/...
MAINLY VFR CONDITIONS ARE EXPECTED AT THE TAF SITES THROUGH THE
END OF THE TAF PERIOD ENDING AT 06Z FRI. SKIES WILL GENERALLY BE
OVC035-080 THROUGH THE OVERNIGHT AND THEN SCT025-035 SCT100 ON
THURSDAY AND THEN BECOME SKC THU EVENING.
THE WEST-NORTHWEST WINDS TOO WILL BE ON THE INCREASE AS PRESSURE
GRADIENT REMAINS TIGHT. AS MIXING LAYER HEIGHTS INCREASE DURING
THURSDAY...WIND GUSTS WILL INCREASE TO AROUND 30 KTS. THE WINDS
WILL GRADUALLY DIMINISH THU EVENING BECOMING LIGHT AND VARIABLE
AFTER DARK.
OUTLOOK...
THURSDAY NIGHT: LOW OPERATIONAL IMPACT. SLIGHT CHANCE OF SHSN.
FRIDAY TO SATURDAY: NO OPERATIONAL IMPACT. NO SIG WX.
SATURDAY NIGHT: LOW OPERATIONAL IMPACT. SLIGHT CHANCE OF SHSN.
SUNDAY: MODERATE OPERATIONAL IMPACT. CHANCE OF SHRA...SHSN.
SUNDAY NIGHT: LOW OPERATIONAL IMPACT. SLIGHT CHANCE OF SHSN.
MONDAY: LOW OPERATIONAL IMPACT. SLIGHT CHANCE OF SHRA...SHSN.
&&
.HYDROLOGY...
THE RIVERS HAVE CRESTED...AND FLOWS ARE STARTING TO DECREASE WITH
THE COLDER TEMPS. THE TREND THE NEXT 5 DAYS ARE FOR FLOWS TO
DECREASE IN THE COLD AND DRY AIR MASS INTO THE HOLIDAY WEEKEND.
ANY PRECIP WILL BE IN THE FORM OF SNOW SHOWERS PREDOMINANTLY WEST
OF THE HUDSON RIVER VALLEY TODAY INTO FRIDAY. A CLIPPER LOW MAY
BRING SOME SCT SNOW SHOWERS TO THE REGION TO CLOSE THE WEEKEND
WITH VERY LIGHT QPF. MOST LOCATIONS OUTSIDE OF THE FAVORED LAKE
EFFECT AREAS ARE NOT EXPECTED TO RECEIVE A TENTH OF AN INCH OF
LIQUID EQUIVALENT THE NEXT 5 DAYS.
FOR DETAILS ON SPECIFIC AREA RIVERS AND LAKES...INCLUDING OBSERVED
AND FORECAST RIVER STAGES AND LAKE ELEVATIONS...PLEASE VISIT THE
ADVANCED HYDROLOGIC PREDICTION SERVICE /AHPS/ GRAPHS ON OUR WEBSITE.
&&
.ALY WATCHES/WARNINGS/ADVISORIES...
CT...NONE.
NY...LAKE EFFECT SNOW ADVISORY UNTIL 7 AM EST FRIDAY FOR NYZ038.
MA...NONE.
VT...NONE.
&&
$$
SYNOPSIS...WASULA
NEAR TERM...WASULA
SHORT TERM...WASULA
LONG TERM...11
AVIATION...11
HYDROLOGY...JPV/WASULA
AREA FORECAST DISCUSSION...UPDATED
NWS MIAMI FL
1224 PM EST THU NOV 28 2013
.AVIATION...
THE WINDS WILL BE SWINGING TO A NORTHEAST DIRECTION EARLY THIS
AFTERNOON AND REMAIN NORTHEAST THROUGH TONIGHT. THE SPEEDS WILL BE
5 TO 10 KNOTS THIS AFTERNOON INTO TONIGHT AT ALL OF THE TAF
SITES...EXCEPT FOR KAPF TAF SITE WHERE THE SPEEDS WILL DROP DOWN
TO 3 KNOTS AFTER 23Z TONIGHT. SOME CLOUDS FROM THE ATLANTIC WATERS
WILL WORK INTO KFLL AND KPBI TAF STIES THIS AFTERNOON...BUT SHOULD
REMAIN IN THE VFR CONDITIONS ALONG WITH THE VIS IN THE VFR
CONDITIONS. REST OF THE TAF SITES OVER SOUTH FLORIDA WILL ALSO
REMAIN IN THE VFR CONDITIONS FOR THE SKY AND VIS.
&&
.AVIATION...54/BNB
.PREV DISCUSSION... /ISSUED 951 AM EST THU NOV 28 2013/
UPDATE...
OUTSIDE OF A FEW MINOR TWEAKS BASED ON THE LATEST OBSERVATIONS
AROUND THE LOCAL AREA...NO MAJOR UPDATES WERE NECESSARY. THE
WINDS OVER LAKE OKEECHOBEE WERE SLIGHTLY HIGHER THAN ORIGINALLY
EXPECTED DUE TO STRONGER WINDS MIXING DOWN OVER THE WARMER LAKE
WATERS...WHICH HAS PROMPTED A SHORT-FUSED ADVISORY. THESE WINDS
SHOULD TREND DOWN THROUGH THE LATE MORNING AND AFTERNOON PERIOD AS
THE GRADIENT RELAXES.
THE MAIN STORY THIS MORNING HAS BEEN THE COOL TEMPERATURES...WHICH
MARKS THE COOLEST MORNING OF THE SEASON FOR SOUTH FLORIDA.
BRIGHTON IN NORTHERN GLADES COUNTY BRIEFLY DROPPED TO 36 DEGREES
..WHICH WAS THE COLDEST RECORDED TEMPERATURE IN OUR LOCAL AREA
TODAY. ELSEWHERE...TEMPERATURES RANGED FROM THE UPPER 30S FROM THE
INTERIOR AREAS (PALMDALE TO IMMOKALEE) TO THE LOWER 50S ALONG THE
COAST IN MIAMI-DADE COUNTY. THE MORNING SOUNDING AT MIAMI
REFLECTED THIS COOL AIR AT THE SURFACE BELOW A STRONG LOW-LEVEL
INVERSION AROUND 1700 FT...THEN TOPPED WITH A SUBSTANTIAL AMOUNT
OF DRY AIR ABOVE 3500 FT (PWAT OF .5"). THE LATEST RUC ANALYSIS
HAS LINED UP WELL WITH THE CURRENT SYNOPTIC PATTERN AND GENERALLY
INDICATES THE COLD AIR ADVECTION COMING TO AN END LATER TODAY AS
THE LOW-LEVEL FLOW QUICKLY SHIFTS TO THE NORTHEAST. AFTERNOON
HIGHS ARE FORECAST TO CLIMB INTO THE LOWER 70S.
&&
.UPDATED...AG
PREV DISCUSSION... /ISSUED 645 AM EST THU NOV 28 2013/
AVIATION...VFR WILL PREVAIL. SKIES WILL BE MOSTLY CLEAR AT KAPF
THROUGH THE PERIOD. FOR THE EAST COAST, EXPECT SCT-BKN STRATO CU
TO INCREASE LATER TODAY...AT AROUND 5K FT. BRIEF MVFR CIGS WILL
CONTINUE IN MIAMI-DADE OVER THE NEXT HOUR BUT ARE EXPECTED TO
IMPROVE. MOISTURE LOOKS TOO SHALLOW TO ADD ANY SHOWER MENTION.
WINDS WILL PREVAIL NW AT NEAR 10 KT. GFS/NAM MOS LIKELY BRINGING
WINDS OUT OF THE NE TOO QUICKLY ATLANTIC TERMINALS. HRRR LOOKS TO
HAVE THE RIGHT IDEA, DELAYING NE WINDS UNTIL 18-19Z. /GREGORIA
&&
PREV DISCUSSION... /ISSUED 406 AM EST THU NOV 28 2013/
DISCUSSION...
TEMPERATURES IN THE LOW TO MID 50S ARE SEEN THIS MORNING ALONG
THE EAST COAST WITH MID TO UPPER 40S ACROSS THE INTERIOR WITH
BRISK NORTHERLY WINDS. WINDS SHOULD BEGIN TO VEER MORE TO THE
NORTHEAST THROUGH THE DAY ALLOWING MORE OF A MARITIME INFLUENCE
AND WEAK MOISTURE RETURN ACROSS THE AREA PARTICULARLY FOR THE
EASTERN HALF OF THE AREA. HOWEVER...GENERALLY RAIN FREE WEATHER
SHOULD PREVAIL THROUGH THE DAY.
NORTHEAST FLOW SHOULD THEN PERSIST THROUGH THE WEEKEND AS HIGH
PRESSURE REMAINS CENTERED JUST OFF THE CAROLINA COAST. THIS FLOW
REGIME WILL ALLOW FOR A FEW SHOWERS TO STREAM ACROSS THE ATLANTIC
WATERS AND INTO THE EAST COAST METRO AREAS DURING THIS TIME FRAME
ALONG WITH SLIGHTLY WARMER TEMPERATURES.
BY EARLY NEXT WEEK...A WEAK H5 SHORTWAVE IS FORECAST TO SURGE TO
THE SOUTHEAST ACROSS THE DEEP SOUTH AND INTO NORTHERN FLORIDA. AS
IT DOES...AN ASSOCIATED SURFACE LOW ACROSS THE WESTERN ATLANTIC
WILL PULL TO THE NORTHEAST WRAPPING SOME DEEPER MOISTURE ACROSS
THE FLORIDA PENINSULA RESULTING IN SLIGHT CHANCES FOR SHOWERS ON
MONDAY. AS THE LOW CONTINUES TO MOVE ON...IT WILL SWING A COLD
FRONT THROUGH THE AREA LATE MONDAY INTO TUESDAY WITH A RETURN TO
DRIER CONDITIONS WITH MORE NORTHWEST TO NORTHERLY FLOW AND COOLER
TEMPERATURES.
MARINE...
FRESH NORTH TO NORTHEASTERLY WINDS WILL PREVAIL TODAY AND THROUGH
THE WEEKEND WITH HIGH PRESSURE SITUATED ACROSS THE WESTERN
ATLANTIC. SEAS ACROSS THE GULF WATERS WILL BEGIN TO SUBSIDE
THROUGH THE DAY AS WINDS BECOME MORE OFFSHORE. ACROSS THE
ATLANTIC...SEAS SHOULD REMAIN NEAR ADVISORY LEVELS THROUGH
SATURDAY BEFORE WINDS SUBSIDE SLIGHTLY.
&&
.PRELIMINARY POINT TEMPS/POPS...
WEST PALM BEACH 72 65 77 68 / - - 10 10
FORT LAUDERDALE 73 67 79 71 / - - 10 10
MIAMI 73 65 79 69 / - - 10 10
NAPLES 73 56 81 60 / - - - -
&&
.MFL WATCHES/WARNINGS/ADVISORIES...
FL...NONE.
AM...SMALL CRAFT ADVISORY UNTIL 1 PM EST THIS AFTERNOON FOR COASTAL
WATERS FROM DEERFIELD BEACH TO OCEAN REEF, FL OUT 20 NM-
LAKE OKEECHOBEE-WATERS FROM DEERFIELD BEACH TO OCEAN REEF,
FL EXTENDING FROM 20 NM TO THE TERRITORIAL WATERS OF THE
BAHAMAS.
SMALL CRAFT ADVISORY UNTIL 1 PM EST THIS AFTERNOON FOR COASTAL
WATERS FROM JUPITER INLET TO DEERFIELD BEACH, FL OUT 20 NM-
WATERS FROM JUPITER INLET TO DEERFIELD BEACH, FL EXTENDING
FROM 20 NM TO 60 NM.
GM...SMALL CRAFT ADVISORY UNTIL 1 PM EST THIS AFTERNOON FOR COASTAL
WATERS FROM CHOKOLOSKEE TO BONITA BEACH, FL OUT 20 NM-
COASTAL WATERS FROM EAST CAPE SABLE TO CHOKOLOSKEE, FL OUT
20 NM-GULF WATERS FROM CHOKOLOSKEE TO BONITA BEACH, FL
EXTENDING FROM 20 TO 60 NM.
&&
$$
DISCUSSION/MARINE/FIRE...10/CD
AVIATION/RADAR...57/DG
AREA FORECAST DISCUSSION
NWS MIAMI FL
951 AM EST THU NOV 28 2013
.UPDATE...
OUTSIDE OF A FEW MINOR TWEAKS BASED ON THE LATEST OBSERVATIONS
AROUND THE LOCAL AREA...NO MAJOR UPDATES WERE NECESSARY. THE
WINDS OVER LAKE OKEECHOBEE WERE SLIGHTLY HIGHER THAN ORIGINALLY
EXPECTED DUE TO STRONGER WINDS MIXING DOWN OVER THE WARMER LAKE
WATERS...WHICH HAS PROMPTED A SHORT-FUSED ADVISORY. THESE WINDS
SHOULD TREND DOWN THROUGH THE LATE MORNING AND AFTERNOON PERIOD AS
THE GRADIENT RELAXES.
THE MAIN STORY THIS MORNING HAS BEEN THE COOL TEMPERATURES...WHICH
MARKS THE COOLEST MORNING OF THE SEASON FOR SOUTH FLORIDA.
BRIGHTON IN NORTHERN GLADES COUNTY BRIEFLY DROPPED TO 36 DEGREES
...WHICH WAS THE COLDEST RECORDED TEMPERATURE IN OUR LOCAL AREA
TODAY. ELSEWHERE...TEMPERATURES RANGED FROM THE UPPER 30S FROM THE
INTERIOR AREAS (PALMDALE TO IMMOKALEE) TO THE LOWER 50S ALONG THE
COAST IN MIAMI-DADE COUNTY. THE MORNING SOUNDING AT MIAMI
REFLECTED THIS COOL AIR AT THE SURFACE BELOW A STRONG LOW-LEVEL
INVERSION AROUND 1700 FT...THEN TOPPED WITH A SUBSTANTIAL AMOUNT
OF DRY AIR ABOVE 3500 FT (PWAT OF .5"). THE LATEST RUC ANALYSIS
HAS LINED UP WELL WITH THE CURRENT SYNOPTIC PATTERN AND GENERALLY
INDICATES THE COLD AIR ADVECTION COMING TO AN END LATER TODAY AS
THE LOW-LEVEL FLOW QUICKLY SHIFTS TO THE NORTHEAST. AFTERNOON
HIGHS ARE FORECAST TO CLIMB INTO THE LOWER 70S. AG
&&
.PREV DISCUSSION... /ISSUED 645 AM EST THU NOV 28 2013/
AVIATION...VFR WILL PREVAIL. SKIES WILL BE MOSTLY CLEAR AT KAPF
THROUGH THE PERIOD. FOR THE EAST COAST, EXPECT SCT-BKN STRATO CU
TO INCREASE LATER TODAY...AT AROUND 5K FT. BRIEF MVFR CIGS WILL
CONTINUE IN MIAMI-DADE OVER THE NEXT HOUR BUT ARE EXPECTED TO
IMPROVE. MOISTURE LOOKS TOO SHALLOW TO ADD ANY SHOWER MENTION.
WINDS WILL PREVAIL NW AT NEAR 10 KT. GFS/NAM MOS LIKELY BRINGING
WINDS OUT OF THE NE TOO QUICKLY ATLANTIC TERMINALS. HRRR LOOKS TO
HAVE THE RIGHT IDEA, DELAYING NE WINDS UNTIL 18-19Z. /GREGORIA
PREV DISCUSSION... /ISSUED 406 AM EST THU NOV 28 2013/
DISCUSSION...
TEMPERATURES IN THE LOW TO MID 50S ARE SEEN THIS MORNING ALONG
THE EAST COAST WITH MID TO UPPER 40S ACROSS THE INTERIOR WITH
BRISK NORTHERLY WINDS. WINDS SHOULD BEGIN TO VEER MORE TO THE
NORTHEAST THROUGH THE DAY ALLOWING MORE OF A MARITIME INFLUENCE
AND WEAK MOISTURE RETURN ACROSS THE AREA PARTICULARLY FOR THE
EASTERN HALF OF THE AREA. HOWEVER...GENERALLY RAIN FREE WEATHER
SHOULD PREVAIL THROUGH THE DAY.
NORTHEAST FLOW SHOULD THEN PERSIST THROUGH THE WEEKEND AS HIGH
PRESSURE REMAINS CENTERED JUST OFF THE CAROLINA COAST. THIS FLOW
REGIME WILL ALLOW FOR A FEW SHOWERS TO STREAM ACROSS THE ATLANTIC
WATERS AND INTO THE EAST COAST METRO AREAS DURING THIS TIME FRAME
ALONG WITH SLIGHTLY WARMER TEMPERATURES.
BY EARLY NEXT WEEK...A WEAK H5 SHORTWAVE IS FORECAST TO SURGE TO
THE SOUTHEAST ACROSS THE DEEP SOUTH AND INTO NORTHERN FLORIDA. AS
IT DOES...AN ASSOCIATED SURFACE LOW ACROSS THE WESTERN ATLANTIC
WILL PULL TO THE NORTHEAST WRAPPING SOME DEEPER MOISTURE ACROSS
THE FLORIDA PENINSULA RESULTING IN SLIGHT CHANCES FOR SHOWERS ON
MONDAY. AS THE LOW CONTINUES TO MOVE ON...IT WILL SWING A COLD
FRONT THROUGH THE AREA LATE MONDAY INTO TUESDAY WITH A RETURN TO
DRIER CONDITIONS WITH MORE NORTHWEST TO NORTHERLY FLOW AND COOLER
TEMPERATURES.
MARINE...
FRESH NORTH TO NORTHEASTERLY WINDS WILL PREVAIL TODAY AND THROUGH
THE WEEKEND WITH HIGH PRESSURE SITUATED ACROSS THE WESTERN
ATLANTIC. SEAS ACROSS THE GULF WATERS WILL BEGIN TO SUBSIDE
THROUGH THE DAY AS WINDS BECOME MORE OFFSHORE. ACROSS THE
ATLANTIC...SEAS SHOULD REMAIN NEAR ADVISORY LEVELS THROUGH
SATURDAY BEFORE WINDS SUBSIDE SLIGHTLY.
&&
.PRELIMINARY POINT TEMPS/POPS...
WEST PALM BEACH 72 64 77 68 / - - 10 10
FORT LAUDERDALE 73 67 79 71 / - - 10 10
MIAMI 73 65 79 69 / - - 10 10
NAPLES 73 56 81 60 / - - - -
&&
.MFL WATCHES/WARNINGS/ADVISORIES...
FL...NONE.
AM...SMALL CRAFT ADVISORY UNTIL 1 PM EST THIS AFTERNOON FOR COASTAL
WATERS FROM DEERFIELD BEACH TO OCEAN REEF, FL OUT 20 NM-
LAKE OKEECHOBEE-WATERS FROM DEERFIELD BEACH TO OCEAN REEF,
FL EXTENDING FROM 20 NM TO THE TERRITORIAL WATERS OF THE
BAHAMAS.
SMALL CRAFT ADVISORY UNTIL 1 PM EST THIS AFTERNOON FOR COASTAL
WATERS FROM JUPITER INLET TO DEERFIELD BEACH, FL OUT 20 NM-
WATERS FROM JUPITER INLET TO DEERFIELD BEACH, FL EXTENDING
FROM 20 NM TO 60 NM.
GM...SMALL CRAFT ADVISORY UNTIL 1 PM EST THIS AFTERNOON FOR COASTAL
WATERS FROM CHOKOLOSKEE TO BONITA BEACH, FL OUT 20 NM-
COASTAL WATERS FROM EAST CAPE SABLE TO CHOKOLOSKEE, FL OUT
20 NM-GULF WATERS FROM CHOKOLOSKEE TO BONITA BEACH, FL
EXTENDING FROM 20 TO 60 NM.
&&
$$
DISCUSSION/MARINE/FIRE...85/AG
AVIATION/RADAR...54/BNB
AREA FORECAST DISCUSSION
NWS MIAMI FL
645 AM EST THU NOV 28 2013
.AVIATION...VFR WILL PREVAIL. SKIES WILL BE MOSTLY CLEAR AT KAPF
THROUGH THE PERIOD. FOR THE EAST COAST, EXPECT SCT-BKN STRATO CU
TO INCREASE LATER TODAY...AT AROUND 5K FT. BRIEF MVFR CIGS WILL
CONTINUE IN MIAMI-DADE OVER THE NEXT HOUR BUT ARE EXPECTED TO
IMPROVE. MOISTURE LOOKS TOO SHALLOW TO ADD ANY SHOWER MENTION.
WINDS WILL PREVAIL NW AT NEAR 10 KT. GFS/NAM MOS LIKELY BRINGING
WINDS OUT OF THE NE TOO QUICKLY ATLANTIC TERMINALS. HRRR LOOKS TO
HAVE THE RIGHT IDEA, DELAYING NE WINDS UNTIL 18-19Z. /GREGORIA
&&
.PREV DISCUSSION... /ISSUED 406 AM EST THU NOV 28 2013/
DISCUSSION...
TEMPERATURES IN THE LOW TO MID 50S ARE SEEN THIS MORNING ALONG
THE EAST COAST WITH MID TO UPPER 40S ACROSS THE INTERIOR WITH
BRISK NORTHERLY WINDS. WINDS SHOULD BEGIN TO VEER MORE TO THE
NORTHEAST THROUGH THE DAY ALLOWING MORE OF A MARITIME INFLUENCE
AND WEAK MOISTURE RETURN ACROSS THE AREA PARTICULARLY FOR THE
EASTERN HALF OF THE AREA. HOWEVER...GENERALLY RAIN FREE WEATHER
SHOULD PREVAIL THROUGH THE DAY.
NORTHEAST FLOW SHOULD THEN PERSIST THROUGH THE WEEKEND AS HIGH
PRESSURE REMAINS CENTERED JUST OFF THE CAROLINA COAST. THIS FLOW
REGIME WILL ALLOW FOR A FEW SHOWERS TO STREAM ACROSS THE ATLANTIC
WATERS AND INTO THE EAST COAST METRO AREAS DURING THIS TIME FRAME
ALONG WITH SLIGHTLY WARMER TEMPERATURES.
BY EARLY NEXT WEEK...A WEAK H5 SHORTWAVE IS FORECAST TO SURGE TO
THE SOUTHEAST ACROSS THE DEEP SOUTH AND INTO NORTHERN FLORIDA. AS
IT DOES...AN ASSOCIATED SURFACE LOW ACROSS THE WESTERN ATLANTIC
WILL PULL TO THE NORTHEAST WRAPPING SOME DEEPER MOISTURE ACROSS
THE FLORIDA PENINSULA RESULTING IN SLIGHT CHANCES FOR SHOWERS ON
MONDAY. AS THE LOW CONTINUES TO MOVE ON...IT WILL SWING A COLD
FRONT THROUGH THE AREA LATE MONDAY INTO TUESDAY WITH A RETURN TO
DRIER CONDITIONS WITH MORE NORTHWEST TO NORTHERLY FLOW AND COOLER
TEMPERATURES.
MARINE...
FRESH NORTH TO NORTHEASTERLY WINDS WILL PREVAIL TODAY AND THROUGH
THE WEEKEND WITH HIGH PRESSURE SITUATED ACROSS THE WESTERN
ATLANTIC. SEAS ACROSS THE GULF WATERS WILL BEGIN TO SUBSIDE
THROUGH THE DAY AS WINDS BECOME MORE OFFSHORE. ACROSS THE
ATLANTIC...SEAS SHOULD REMAIN NEAR ADVISORY LEVELS THROUGH
SATURDAY BEFORE WINDS SUBSIDE SLIGHTLY.
&&
.PRELIMINARY POINT TEMPS/POPS...
WEST PALM BEACH 72 64 77 68 / - - 10 10
FORT LAUDERDALE 73 67 79 71 / - - 10 10
MIAMI 73 65 79 69 / - - 10 10
NAPLES 73 56 81 60 / - - - -
&&
.MFL WATCHES/WARNINGS/ADVISORIES...
FL...NONE.
AM...SMALL CRAFT ADVISORY UNTIL 1 PM EST THIS AFTERNOON FOR COASTAL
WATERS FROM DEERFIELD BEACH TO OCEAN REEF, FL OUT 20 NM-
WATERS FROM DEERFIELD BEACH TO OCEAN REEF, FL EXTENDING
FROM 20 NM TO THE TERRITORIAL WATERS OF THE BAHAMAS.
SMALL CRAFT ADVISORY UNTIL 1 PM EST THIS AFTERNOON FOR COASTAL
WATERS FROM JUPITER INLET TO DEERFIELD BEACH, FL OUT 20 NM-
WATERS FROM JUPITER INLET TO DEERFIELD BEACH, FL EXTENDING
FROM 20 NM TO 60 NM.
GM...SMALL CRAFT ADVISORY UNTIL 1 PM EST THIS AFTERNOON FOR COASTAL
WATERS FROM CHOKOLOSKEE TO BONITA BEACH, FL OUT 20 NM-
COASTAL WATERS FROM EAST CAPE SABLE TO CHOKOLOSKEE, FL OUT
20 NM-GULF WATERS FROM CHOKOLOSKEE TO BONITA BEACH, FL
EXTENDING FROM 20 TO 60 NM.
&&
$$
AREA FORECAST DISCUSSION
NWS MIAMI FL
1243 AM EST THU NOV 28 2013
.AVIATION...VFR WILL PREVAIL. SKIES WILL BE SKC AT KAPF THROUGH
THE PERIOD AND SKC-FEW050 EAST COAST THROUGH EARLY AFTERNOON,
BEFORE STRATO CU MOVES ONSHORE FROM THE ATLANTIC. EXPECTING BKN050
TO PREVAIL EAST COAST TERMINALS LATE AFTERNOON AND THU NIGHT.
MOISTURE LOOKS TOO SHALLOW TO ADD ANY SHOWER MENTION. WINDS WILL
PREVAIL NW AT NEAR 10 KT. GFS/NAM MOS LIKELY BRINGING WINDS OUT OF
THE NE TOO QUICKLY ATLANTIC TERMINALS. HRRR LOOKS TO HAVE THE
RIGHT IDEA, DELAYING NE WINDS UNTIL 18-19Z. /GREGORIA
&&
.PREV DISCUSSION... /ISSUED 654 PM EST WED NOV 27 2013/
UPDATE...
EXPANDED THE SMALL CRAFT ADVISORY ACROSS THE GULF AND ATLANTIC
WATERS TO INCLUDE LAKE OKEECHOBEE WITH LAKE SENSORS INDICATING
WINDS IN EXCESS OF 20 KNOTS ACROSS PORTIONS OF THE LAKE. AFTER 06Z
THURSDAY WINDS ARE FORECAST TO SLOWLY SUBSIDE...SO WILL LET THE
ADVISORY FOR THE LAKE EXPIRE AT THAT TIME. FOR THE GULF
WATERS...WINDS WILL REMAIN AROUND 20 KNOTS INTO THURSDAY WITH SEAS
OF 8 TO 10 FEET POSSIBLE MAINLY ACROSS THE OFF SHORE WATERS INTO
EARLY THURSDAY AND SLOWLY SUBSIDING INTO THURSDAY AFTERNOON. BASED
ON THE CURRENT FORECAST THE SMALL CRAFT ADVISORY WAS EXTENDED TO
18Z THURSDAY. FOR THE ATLANTIC WATERS...WINDS TO NEAR 20 KNOTS
WILL CONTINUE OVER NIGHT AND SLOWLY SUBSIDE LATER ON THURSDAY. AS
WINDS BECOME MORE NORTHERLY EARLY THURSDAY GULF STREAM SEAS WILL
SLOWLY INCREASE WITH SEAS TO NEAR 7 FEET POSSIBLE BY EARLY
THURSDAY. THE SMALL CRAFT ADVISORY FOR THE ATLANTIC WATERS WAS
ALSO EXTENDED TO 18Z THURSDAY.
60
PREV DISCUSSION... /ISSUED 637 PM EST WED NOV 27 2013/
AVIATION...
SKIES SHOULD REMAIN MOSTLY CLEAR FOR THE EAST COAST TAF SITES
OVERNIGHT. STRATUS AROUND 5KFT WAS MOVING ACROSS THE GULF
WATERS...AND SOME OF THIS WILL MOVE ACROSS KAPF OVERNIGHT. WINDS
WILL SHIFT TO THE NORTH AND NORTHEAST AROUND 10 KNOTS WITH HIGHER
GUSTS THANKSGIVING DAY. SCT/BKN STRATUS AROUND 4KFT WILL MOVE
INTO THE EAST COAST AREAS IN THE AFTERNOON.
PREV DISCUSSION... /ISSUED 222 PM EST WED NOV 27 2013/
DRY AND COOLER CONDITIONS FOR SOUTH FLORIDA ON THANKSGIVING....
SHORT TERM...
A COLD FRONT OVER THE EASTERN PORTION OF SOUTH FLORIDA WILL
CONTINUE TO PUSH EAST THIS AFTERNOON AND SHOULD BE OVER THE
BAHAMAS BY THIS EVENING. THE FRONT WILL CONTINUE TO MOVE EAST
FURTHER INTO THE ATLANTIC WATERS TONIGHT INTO THANKSGIVING DAY
AS HIGH PRESSURE OVER THE CENTRAL UNITED STATES MOVES SOUTHEAST
INTO THE SOUTHEASTERN UNITED STATES. THIS WILL ALLOW FOR DRIER AND
COOLER AIR TO WORK INTO THE AREA FROM THE NORTH TONIGHT INTO
THANKSGIVING DAY...WHICH IN TURN WILL ALLOW FOR THE LOWS TONIGHT
TO FALL DOWN INTO THE 40S OVER THE OVER MOST OF SOUTH FLORIDA
EXCEPT AROUND 40 WEST OF LAKE OKEECHOBEE AND AROUND 50 OVER THE
SOUTHEASTERN METRO AREAS OF SOUTH FLORIDA. THE WINDS WILL ALSO BE
AROUND 5 TO 10 MPH OVER THE METRO AREAS TO AROUND 5 MPH OVER THE
INTERIOR AREAS. THIS WILL ALLOW FOR THE WIND CHILLS TO FALL DOWN
INTO THE LOWER TO MID 40S OVER MOST OF SOUTH FLORIDA LATE
TONIGHT...EXCEPT UPPER 40S TO NEAR 50 OVER METRO BROWARD AND METRO
MIAMI-DADE COUNTIES.
THE HIGH WILL MOVE SLOWLY EAST INTO THE MID ATLANTIC WATERS THIS
WEEKEND ALLOWING FOR THE WIND FLOW TO SWING TO A NORTHEAST
DIRECTION. THIS WILL ALLOW FOR SOME SLOW WARMING IN THE
TEMPERATURES THIS WEEKEND OVER SOUTH FLORIDA. HIGHS ON THURSDAY WILL
BE IN THE 70S BEFORE INCREASING TO THE LOWER TO MID 80S BY THIS
WEEKEND. LOWS ON THANKSGIVING NIGHT WILL BE IN THE 50S TO NEAR 60
BEFORE INCREASING TO THE 60S TO NEAR 70 THIS WEEKEND.
THE WEATHER WILL ALSO BE MOSTLY DRY ACROSS SOUTH FLORIDA THIS
WEEKEND DUE TO THE HIGH NORTH OF THE AREA MOVING SLOWLY EAST. THE
ONLY EXCEPTION TO THIS IS OVER THE EAST COAST METRO AREAS WHERE A
FEW SHOWERS COULD OCCUR ON THE NORTHEAST WIND FLOW. SO WILL KEEP A
10 PERCENT POPS IN PLACE FOR THE EAST COAST METRO AREAS FOR THIS
WEEKEND.
LONG TERM...
THE HIGH WILL CONTINUE TO MOVE EAST INTO THE ATLANTIC WATERS EARLY
NEXT WEEK ALLOWING FOR ANOTHER COLD FRONT CURRENTLY OVER THE
NORTHWEST PORTION OF THE UNITED STATES TO MOVE SOUTHEAST AND
THROUGH SOUTH FLORIDA. THIS FRONT WILL BRING A SLIGHT CHANCE OF
SHOWERS TO THE EARLY NEXT WEEK...BEFORE DRY WEATHER WORKS BACK
INTO THE AREA FROM THE NORTH.
AVIATION...
VFR CONDITIONS WILL PREVAIL FOR NEXT 24 HOURS AS HIGH PRESSURE
BUILDS SOUTH INTO THE REGION. NORTHWEST WINDS OF 15-25 KTS TODAY
WILL DIMINISH TO 10 KTS OVERNIGHT...BUT INCREASE AGAIN THURSDAY TO
15-20 KTS. WINDS SHOULD ALSO VEER TO NORTH-NORTHEAST BY MID-MORNING
THURSDAY.
MARINE...
THE WINDS WILL BE NORTHERLY DIRECTION TONIGHT BEFORE SWINGING TO A
NORTHEAST DIRECTION ON THANKSGIVING DAY...AND REMAIN AT A
NORTHEAST DIRECTION THIS WEEKEND. THE WIND SPEEDS WILL ALSO REMAIN
AT LEAST 20 KNOTS OVER THE MOST OF THE LOCAL WATERS...EXCEPT 15
TO 20 KNOTS OVER BISCAYNE BAY AND LAKE OKEECHOBEE TONIGHT THROUGH
FRIDAY NIGHT. THIS WILL KEEP THE SEAS IN THE ATLANTIC WATERS AT 5
TO 7 FEET TONIGHT INTO FRIDAY NIGHT. FOR THE GULF SIDE...THE SEAS
WILL BE 5 TO 7 FEET UP TO 10 FEET IN THE OFFSHORE WATERS TONIGHT
BEFORE SLOWLY DECREASING TO LESS THAN 7 FEET BY THANKSGIVING
NIGHT. SO WILL CONTINUE THE SCA FOR BOTH THE ATLANTIC AND GULF
WATERS OF SOUTH FLORIDA FOR TONIGHT WITH A SCEC FOR BISCAYNE BAY
AND LAKE OKEECHOBEE WATERS.
FIRE WEATHER...
THE RELATIVE HUMIDITY VALUES ON THANKSGIVING DAY SHOULD REMAIN ABOVE THE
35 PERCENT CRITICAL VALUE OVER SOUTH FLORIDA. HOWEVER...SOME
ISOLATED AREAS OVER THE INTERIOR AND METRO AREAS OF COLLIER COUNTY
COULD FALL DOWN CLOSE TO THE 35 PERCENT CRITICAL VALUE DURING THE
AFTERNOON HOURS. AT THIS TIME...THE ENERGY RELEASE COMPONENT WILL
REMAIN IN THE LOWER 20S FOR THANKSGIVING DAY AND THE 20 FOOT WINDS
WILL REMAIN BELOW 15 MPH. SO WILL NOT BE ISSUING ANY FIRE WEATHER
WATCH OR RED FLAG WARNINGS FOR COLLIER COUNTY OR REST OF SOUTH
FLORIDA FOR THANKSGIVING DAY.
&&
.PRELIMINARY POINT TEMPS/POPS...
WEST PALM BEACH 64 77 69 80 / - 10 10 10
FORT LAUDERDALE 66 78 71 80 / - 10 10 10
MIAMI 67 79 71 81 / - 10 10 10
NAPLES 56 79 61 81 / - - - -
&&
.MFL WATCHES/WARNINGS/ADVISORIES...
FL...RIP CURRENT RISK UNTIL 7 AM EST THIS MORNING FOR COASTAL COLLIER.
AM...SMALL CRAFT ADVISORY UNTIL 1 PM EST THIS AFTERNOON FOR COASTAL
WATERS FROM DEERFIELD BEACH TO OCEAN REEF, FL OUT 20 NM-
WATERS FROM DEERFIELD BEACH TO OCEAN REEF, FL EXTENDING
FROM 20 NM TO THE TERRITORIAL WATERS OF THE BAHAMAS.
SMALL CRAFT ADVISORY UNTIL 1 PM EST THIS AFTERNOON FOR COASTAL
WATERS FROM JUPITER INLET TO DEERFIELD BEACH, FL OUT 20 NM-
WATERS FROM JUPITER INLET TO DEERFIELD BEACH, FL EXTENDING
FROM 20 NM TO 60 NM.
SMALL CRAFT ADVISORY UNTIL 1 AM EST EARLY THIS MORNING FOR LAKE
OKEECHOBEE.
GM...SMALL CRAFT ADVISORY UNTIL 1 PM EST THIS AFTERNOON FOR COASTAL
WATERS FROM CHOKOLOSKEE TO BONITA BEACH, FL OUT 20 NM-
COASTAL WATERS FROM EAST CAPE SABLE TO CHOKOLOSKEE, FL OUT
20 NM-GULF WATERS FROM CHOKOLOSKEE TO BONITA BEACH, FL
EXTENDING FROM 20 TO 60 NM.
&&
$$
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
230 PM CST THU NOV 28 2013
.DISCUSSION...
306 AM CST
THE PRIMARY FORECAST CONCERNS ARE CENTERED ON CLOUD COVER AND
TEMPERATURES THROUGH THE WEEKEND AND THEN CHANCES FOR PRECIPITATION
NEXT WEEK IN WHAT APPEARS TO POSSIBLY BE AN UNSETTLED
PATTERN...ALTHOUGH A HIGH DEGREE OF UNCERTAINTY.
ONE MORE SHORT WAVE IS DIVING SOUTHEAST ACROSS THE GREAT LAKES THIS
THANKSGIVING MORNING IN WHAT HAS BEEN A LITERAL PARADE OF THESE
COLD-AIR-REINFORCING SYSTEMS. A 1017MB SURFACE LOW REFLECTION ACROSS
IA WILL TRANSLATE EAST THIS MORNING AND WEAKEN AS IT DOES SUCH.
MORNING CLOUDS IN PLACE WERE DEVELOPED WITHIN THE WARM AIR ADVECTION
ENVELOPE OF THIS SYSTEM AND AS SUCH HAVE BASES MAINLY ABOVE 5000
FT...SO BELIEVE THEY WILL VACATE BY AFTERNOON ACROSS THE WESTERN AND
SOUTHERN FORECAST AREA GIVEN THE CLOUD-BEARING WIND FLOW. LOW-LEVEL
LAPSE RATES ARE MODESTLY STEEP BEHIND THE SYSTEM WITH SOME MARGINAL
SATURATION FORECAST AT THE TOP OF THE MIXED LAYER...SO LIKELY SOME
SCATTERED STRATOCU WILL CONTINUE. ALL-IN-ALL...EXPECTING SOME SUN
LATE THIS MORNING AND AFTERNOON. GIVEN THE 850MB AND 925MB FORECAST
TEMPS BY THE RAP AND NAM THIS AFTERNOON...WE ONCE AGAIN ARE IN THE
BOTTOM TENTH PERCENTILE FOR THIS TIME OF YEAR. THIS FAVORS HIGHS IN
THE LOWER TO MID 30S. SEE THE CLIMATE DISCUSSION BELOW FOR MORE ON
WHERE THIS STACKS UP FOR THANKSGIVING DAYS.
AS A CANADIAN SURFACE HIGH MOVES OVERHEAD TONIGHT TEMPERATURES
SHOULD RADIATE QUICKLY THIS EVE...EVEN IF IT DOES TAKE A FEW HOURS
AFTER SUNSET TO DIMINISH THE LINGERING STRATOCU. HAVE MID AND EVEN
PATCHY LOWER TEENS IN OUTLYING AREAS. AS THE WIND FIELD OVER LAKE MI
SHIFTS MORE NE TONIGHT IMMEDIATELY AHEAD OF THE HIGH CENTER...A LAKE
PLUME OF AT LEAST CLOUDS LOOKS LIKELY INTO NORTHWEST INDIANA AND
POSSIBLY NORTHEAST ILLINOIS. LAKE-INDUCED EQUILIBRIUM LEVELS AROUND
4500 FT FORECAST BY THE NAM SEEM A LITTLE SHALLOW FOR PRECIP AND ANY
PRONOUNCED CONVERGENCE IS UNLIKELY. HAVE THUS ONLY ADDED A LOW
CHANCE FOR SOME LIGHT SNOW IN NORTHWEST IN/FAR SOUTHEAST COOK COUNTY
LATE TONIGHT AS WELL AS BUMPED UP CLOUD COVER.
A MORE ZONAL PATTERN WILL MOVE OVER BY LATER FRIDAY INTO SATURDAY
BRINGING MODERATING TEMPERATURES. THERE IS A FAIR AMOUNT OF SPREAD
IN THE ENVELOPE OF GUIDANCE SOLUTIONS FOR HOW WARM SATURDAY WILL
BE...AND POTENTIAL CLOUD COVER LIKELY HAS QUITE A BIT TO DO WITH
THAT. THIS TIME OF YEAR SOUTHERLY LOW-LEVEL FLOW AFTER A COLD AIR
MASS CAN READILY BECOME "CONTAMINATED" WITH SATURATION/CLOUDS.
CLIMATOLOGY OF THE 850MB AND 925MB TEMPERATURES WOULD FAVOR MID AND
MAYBE EVEN UPPER 40S...BUT THAT WARM CURRENTLY SEEMS UNLIKELY WITH
AT LEAST SOME POTENTIAL FOR CLOUDS AND NOT THE STRONGEST OF WARM AIR
ADVECTION SIGNALS. THE HEART OF THE SYSTEM IS OVER THE NORTHERN
GREAT LAKES...SO FORCING AND SATURATION REMAINS MINIMAL OVER THE
AREA. SO HAVE NO POPS AT THIS TIME.
NEXT WEEK THE UNCERTAINTY REALLY STARTS TO RAMP UP BY MIDWEEK AFTER
WHAT IS BECOMING A MORE FAVORED DRY SUNDAY AND MONDAY. ALTHOUGH MUCH
LIKE SATURDAY...TEMPERATURE CONFIDENCE IS FAIRLY LOW GIVEN CLOUD
POTENTIAL. IF CLOUDS ARE REMAINING INTO SUNDAY MORNING THEY VERY
WELL COULD STICK AROUND ALL THE WAY THROUGH MONDAY NIGHT AS SURFACE
PRESSURES ARE FORECAST TO BASICALLY REMAIN THE SAME...I.E. LITTLE
ADVECTION. THE LONG ADVERTISED UPPER TROUGH ACROSS THE WEST COAST
LOOKS TO EVOLVE IN THE BEGINNING OF THE WEEK AND FORCE DOWNSTREAM
RIDGING AND SOUTHWEST FLOW ALOFT. THIS TROUGH SHOULD PACK QUITE A
PUNCH OF COLD AIR INTO THE NORTHERN ROCKIES AND PLAINS...BUT THE
MAIN BAROCLINIC ZONE DURING MIDWEEK LOOKS TO REMAIN TO THE NORTHWEST
AND IF THAT IS THE CASE THEN ANY HEAVY WINTER PRECIP SHOULD AS WELL
DURING MIDWEEK...BUT AGAIN CONFIDENCE IS LOW. ENERGY THAT TRANSLATES
EAST FROM THIS TROUGH APPEARS TO BE IN PARTS AND THUS MULTIPLE
CHANCES FOR PRECIP LOOK TO BE THE CASE ACROSS THE GREAT LAKES AND
CORN BELT REGIONS DURING THE DEC 3-8 PERIOD. NIGHTTIME TEMPERATURES
SHOULD BE MORE NEAR NORMAL OR EVEN ABOVE NORMAL GIVEN CLOUD
COVER DURING MIDWEEK...BUT DAYTIME HIGHS COULD BE ANYWHERE IN A
LARGE SPECTRUM OF SOLUTIONS DEPENDING ON STRENGTH OF SOUTHERLY
FLOW AND WHEN LOW PASSAGES OCCUR. THOSE ARE BOTH VARIABLES DIFFICULT
TO LOCK DOWN IN A FORECAST PATTERN OF A BROAD TROUGH IN THE WEST.
MTF
&&
.CLIMATE...
306 AM CST
THE FORECAST HIGH TODAY FOR CHICAGO (O`HARE) IS 33 WHICH WOULD TIE
MULTIPLE THANKSGIVINGS IN THE PAST TWO DECADES FOR A COOL
HIGH...THE LAST BEING 2007. HOWEVER IF THE MERCURY STAYS BELOW
THAT...IT WOULD BE THE COLDEST HIGH TEMPERATURE ON THANKSGIVING IN
CHICAGO SINCE 1989.
SIMILARLY FOR ROCKFORD...THE 31 DEGREE FORECAST HIGH WOULD BE THE
COOLEST THANKSGIVING HIGH SINCE 1995 AND IF IT STAYS BELOW THAT IT
WOULD BE THE COOLEST SINCE 1989.
MTF
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 20Z...
* WEST NORTHWEST WIND BECOMING MORE NORTHWEST THIS AFTERNOON.
* VFR CEILINGS EXPECTED THIS AFTERNOON...WITH A CHANCE FOR A BRIEF
PERIOD OF MVFR CEILINGS EARLY THIS EVENING.
RODRIGUEZ
//DISCUSSION...UPDATED 18Z...
AN APPROACHING COLD FRONT WILL PUSH ACROSS THE TERMINALS OVER THE
NEXT 1-2 HOURS WITH WEST SOUTHWEST WINDS TURNING TO THE
NORTHWEST...AND A RETURN OF VFR CEILINGS. THIS CLOUD COVER CAN BE
OBSERVED MOVING SOUTHEAST ACROSS EASTERN IOWA AND SOUTHERN
WISCONSIN...WITH DISTANCE SPEED TOOL BRINGING THIS TO RFD BY 19Z
AND TO ORD BY 20Z. SHORT TERM GUIDANCE CONTINUES TO INDICATE THE
POSSIBILITY OF MVFR CEILINGS LATER THIS EVENING...AND CANNOT RULE
THIS OUT WITH COLDER AIR MOVING ACROSS THE REGION. SO HAVE SHOWED
THIS POSSIBILITY IN THE TAF. VFR OR MVFR CEILINGS WILL NOT BE LONG
LASTING THIS EVENING...WITH THIS AREA OF CLOUD COVER EXPECTED TO
QUICKLY EXIT THE TERMINALS AND ONLY HIGH LEVEL CLOUDS TO THEN MOVE
OVER THE TERMINALS THROUGH THE REMAINDER OF THE FORECAST PERIOD.
WINDS WILL DIMINISH TONIGHT AND EVEN BECOME CALM OR LIGHT AND
VARIABLE AS HIGH PRESSURE MOVES OVERHEAD...BUT THEN INCREASE OUT
OF THE SOUTHEAST BY MID DAY FRIDAY.
RODRIGUEZ
//ORD AND MDW CONFIDENCE...UPDATED 20Z...
* HIGH CONFIDENCE WITH WIND SPEED/DIRECTION.
* LOW MEDIUM CONFIDENCE WITH MVFR POTENTIAL EARLY THIS EVENING.
RODRIGUEZ
//OUTLOOK FOR ORD/MDW FOR 00Z SATURDAY-12Z THURSDAY...UPDATED 12Z...
FRIDAY NIGHT...VFR.
SATURDAY...VFR.
SUNDAY AND MONDAY...MVFR POSSIBLE,
TUESDAY...VFR.
WEDNESDAY...CHANCE SHRA...MVFR POSSIBLE.
MDB
&&
.MARINE...
228 PM CST
A BROAD RIDGE OF HIGH PRESSURE CONTINUES TO BE CENTERED ACROSS THE
TENN VALLEY. WITH THE HIGH PRESSURE CENTERED SOUTH OF LAKE
MICHIGAN...AND A WEAK LOW PRESSURE FLOATING SOUTHEAST ACROSS THE
NORTHERN PORTIONS OF LAKE MICHIGAN THIS AFTERNOON...WINDS FOR THE
SOUTHERN TWO-THIRDS OF LAKE MICHIGAN HAVE REMAINED WEST/NORTHWEST
WHILE THE FAR NORTHERN SECTION IS EASTERLY. AT TIMES THE GRADIENT
HAS BEEN TIGHT ENOUGH TO PRODUCE GUSTS TO 25KT NEAR THE
STRAITS...HOWEVER IN GENERAL THE GRADIENT IS EXPECTED TO BE
DIMINISHING.
HIGH PRESSURE WILL BE LIFTING NORTHEAST ACROSS THE NORTHEASTERN
CONUS...WHICH WILL ALLOW WINDS TO BACK TO THE SOUTHWEST/SOUTH FRIDAY
AFTERNOON. THE GRADIENT DOES RAMP UP ALONG THE WESTERN EDGE OF THE
HIGH PRESSURE FRIDAY NIGHT/SATURDAY. GUIDANCE HAS INDICATED THAT
SOUTHERLY GUSTS MAY APPROACH 30KT...AND OCCASIONAL GALE FORCE GUSTS
MAY OCCUR MAINLY FOR THE OPEN WATERS.
A LOW PRESSURE WILL DEVELOP ACROSS THE NORTHERN PLAINS/SOUTHCENTRAL
CANADA LATE FRI NIGHT...THEN STEADILY STRENGTHEN AS IT SLIDES EAST
TOWARDS JAMES BAY SATURDAY AFTN. THIS MAY HELP TO PROLONG HIGHER
GUSTS TO NEAR GALES FOR THE FAR NORTHERN PORTIONS OF LAKE MICHIGAN
SAT. MEANWHILE FURTHER SOUTH THE GRADIENT WILL DIMINISH...WITH WINDS
SHIFTING TO THE WEST THEN NORTH BEHIND A FRONTAL BOUNDARY SUN.
THE GRADIENT DOES APPEAR TO REMAIN MINIMAL SUN NGT...WITH WEAK HIGH
PRESSURE SLIDING NORTHEAST ACROSS NORTHEAST ONTARIO. THIS WILL ALLOW
WINDS TO BECOME EASTERLY FOR EARLY NEXT WEEK...BUT WITH THE LACK OF
ANY SIGNIFICANT GRADIENT...WINDS SHOULD REMAIN ARND 10-20KT FOR
MON/TUE. THEN FOR THE MIDDLE OF NEXT WEEK FORECAST MODELS ARE
INDICATING AN AREA OF LOW PRESSURE TO INTENSIFY ACROSS THE UPPER
MIDWEST AND PIVOT EAST TOWARDS THE NORTHERN GREAT LAKES. THEN YET
ANOTHER LOW PRESSURE TO WATCH LATER IN THE WEEK...WHICH COULD
PROVIDE PROLONGED PERIOD OF SOUTH/SOUTHWEST WINDS AND BUILDING WAVES
FOR THE NORTHERN PORTIONS OF LAKE MICHIGAN TUE NIGHT THROUGH THUR.
BEACHLER
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...NONE.
&&
$$
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AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
147 PM CST THU NOV 28 2013
.DISCUSSION...
306 AM CST
THE PRIMARY FORECAST CONCERNS ARE CENTERED ON CLOUD COVER AND
TEMPERATURES THROUGH THE WEEKEND AND THEN CHANCES FOR PRECIPITATION
NEXT WEEK IN WHAT APPEARS TO POSSIBLY BE AN UNSETTLED
PATTERN...ALTHOUGH A HIGH DEGREE OF UNCERTAINTY.
ONE MORE SHORT WAVE IS DIVING SOUTHEAST ACROSS THE GREAT LAKES THIS
THANKSGIVING MORNING IN WHAT HAS BEEN A LITERAL PARADE OF THESE
COLD-AIR-REINFORCING SYSTEMS. A 1017MB SURFACE LOW REFLECTION ACROSS
IA WILL TRANSLATE EAST THIS MORNING AND WEAKEN AS IT DOES SUCH.
MORNING CLOUDS IN PLACE WERE DEVELOPED WITHIN THE WARM AIR ADVECTION
ENVELOPE OF THIS SYSTEM AND AS SUCH HAVE BASES MAINLY ABOVE 5000
FT...SO BELIEVE THEY WILL VACATE BY AFTERNOON ACROSS THE WESTERN AND
SOUTHERN FORECAST AREA GIVEN THE CLOUD-BEARING WIND FLOW. LOW-LEVEL
LAPSE RATES ARE MODESTLY STEEP BEHIND THE SYSTEM WITH SOME MARGINAL
SATURATION FORECAST AT THE TOP OF THE MIXED LAYER...SO LIKELY SOME
SCATTERED STRATOCU WILL CONTINUE. ALL-IN-ALL...EXPECTING SOME SUN
LATE THIS MORNING AND AFTERNOON. GIVEN THE 850MB AND 925MB FORECAST
TEMPS BY THE RAP AND NAM THIS AFTERNOON...WE ONCE AGAIN ARE IN THE
BOTTOM TENTH PERCENTILE FOR THIS TIME OF YEAR. THIS FAVORS HIGHS IN
THE LOWER TO MID 30S. SEE THE CLIMATE DISCUSSION BELOW FOR MORE ON
WHERE THIS STACKS UP FOR THANKSGIVING DAYS.
AS A CANADIAN SURFACE HIGH MOVES OVERHEAD TONIGHT TEMPERATURES
SHOULD RADIATE QUICKLY THIS EVE...EVEN IF IT DOES TAKE A FEW HOURS
AFTER SUNSET TO DIMINISH THE LINGERING STRATOCU. HAVE MID AND EVEN
PATCHY LOWER TEENS IN OUTLYING AREAS. AS THE WIND FIELD OVER LAKE MI
SHIFTS MORE NE TONIGHT IMMEDIATELY AHEAD OF THE HIGH CENTER...A LAKE
PLUME OF AT LEAST CLOUDS LOOKS LIKELY INTO NORTHWEST INDIANA AND
POSSIBLY NORTHEAST ILLINOIS. LAKE-INDUCED EQUILIBRIUM LEVELS AROUND
4500 FT FORECAST BY THE NAM SEEM A LITTLE SHALLOW FOR PRECIP AND ANY
PRONOUNCED CONVERGENCE IS UNLIKELY. HAVE THUS ONLY ADDED A LOW
CHANCE FOR SOME LIGHT SNOW IN NORTHWEST IN/FAR SOUTHEAST COOK COUNTY
LATE TONIGHT AS WELL AS BUMPED UP CLOUD COVER.
A MORE ZONAL PATTERN WILL MOVE OVER BY LATER FRIDAY INTO SATURDAY
BRINGING MODERATING TEMPERATURES. THERE IS A FAIR AMOUNT OF SPREAD
IN THE ENVELOPE OF GUIDANCE SOLUTIONS FOR HOW WARM SATURDAY WILL
BE...AND POTENTIAL CLOUD COVER LIKELY HAS QUITE A BIT TO DO WITH
THAT. THIS TIME OF YEAR SOUTHERLY LOW-LEVEL FLOW AFTER A COLD AIR
MASS CAN READILY BECOME "CONTAMINATED" WITH SATURATION/CLOUDS.
CLIMATOLOGY OF THE 850MB AND 925MB TEMPERATURES WOULD FAVOR MID AND
MAYBE EVEN UPPER 40S...BUT THAT WARM CURRENTLY SEEMS UNLIKELY WITH
AT LEAST SOME POTENTIAL FOR CLOUDS AND NOT THE STRONGEST OF WARM AIR
ADVECTION SIGNALS. THE HEART OF THE SYSTEM IS OVER THE NORTHERN
GREAT LAKES...SO FORCING AND SATURATION REMAINS MINIMAL OVER THE
AREA. SO HAVE NO POPS AT THIS TIME.
NEXT WEEK THE UNCERTAINTY REALLY STARTS TO RAMP UP BY MIDWEEK AFTER
WHAT IS BECOMING A MORE FAVORED DRY SUNDAY AND MONDAY. ALTHOUGH MUCH
LIKE SATURDAY...TEMPERATURE CONFIDENCE IS FAIRLY LOW GIVEN CLOUD
POTENTIAL. IF CLOUDS ARE REMAINING INTO SUNDAY MORNING THEY VERY
WELL COULD STICK AROUND ALL THE WAY THROUGH MONDAY NIGHT AS SURFACE
PRESSURES ARE FORECAST TO BASICALLY REMAIN THE SAME...I.E. LITTLE
ADVECTION. THE LONG ADVERTISED UPPER TROUGH ACROSS THE WEST COAST
LOOKS TO EVOLVE IN THE BEGINNING OF THE WEEK AND FORCE DOWNSTREAM
RIDGING AND SOUTHWEST FLOW ALOFT. THIS TROUGH SHOULD PACK QUITE A
PUNCH OF COLD AIR INTO THE NORTHERN ROCKIES AND PLAINS...BUT THE
MAIN BAROCLINIC ZONE DURING MIDWEEK LOOKS TO REMAIN TO THE NORTHWEST
AND IF THAT IS THE CASE THEN ANY HEAVY WINTER PRECIP SHOULD AS WELL
DURING MIDWEEK...BUT AGAIN CONFIDENCE IS LOW. ENERGY THAT TRANSLATES
EAST FROM THIS TROUGH APPEARS TO BE IN PARTS AND THUS MULTIPLE
CHANCES FOR PRECIP LOOK TO BE THE CASE ACROSS THE GREAT LAKES AND
CORN BELT REGIONS DURING THE DEC 3-8 PERIOD. NIGHTTIME TEMPERATURES
SHOULD BE MORE NEAR NORMAL OR EVEN ABOVE NORMAL GIVEN CLOUD
COVER DURING MIDWEEK...BUT DAYTIME HIGHS COULD BE ANYWHERE IN A
LARGE SPECTRUM OF SOLUTIONS DEPENDING ON STRENGTH OF SOUTHERLY
FLOW AND WHEN LOW PASSAGES OCCUR. THOSE ARE BOTH VARIABLES DIFFICULT
TO LOCK DOWN IN A FORECAST PATTERN OF A BROAD TROUGH IN THE WEST.
MTF
&&
.CLIMATE...
306 AM CST
THE FORECAST HIGH TODAY FOR CHICAGO (O`HARE) IS 33 WHICH WOULD TIE
MULTIPLE THANKSGIVINGS IN THE PAST TWO DECADES FOR A COOL
HIGH...THE LAST BEING 2007. HOWEVER IF THE MERCURY STAYS BELOW
THAT...IT WOULD BE THE COLDEST HIGH TEMPERATURE ON THANKSGIVING IN
CHICAGO SINCE 1989.
SIMILARLY FOR ROCKFORD...THE 31 DEGREE FORECAST HIGH WOULD BE THE
COOLEST THANKSGIVING HIGH SINCE 1995 AND IF IT STAYS BELOW THAT IT
WOULD BE THE COOLEST SINCE 1989.
MTF
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 20Z...
* WEST NORTHWEST WIND BECOMING MORE NORTHWEST THIS AFTERNOON.
* VFR CEILINGS EXPECTED THIS AFTERNOON...WITH A CHANCE FOR A BRIEF
PERIOD OF MVFR CEILINGS EARLY THIS EVENING.
RODRIGUEZ
//DISCUSSION...UPDATED 18Z...
AN APPROACHING COLD FRONT WILL PUSH ACROSS THE TERMINALS OVER THE
NEXT 1-2 HOURS WITH WEST SOUTHWEST WINDS TURNING TO THE
NORTHWEST...AND A RETURN OF VFR CEILINGS. THIS CLOUD COVER CAN BE
OBSERVED MOVING SOUTHEAST ACROSS EASTERN IOWA AND SOUTHERN
WISCONSIN...WITH DISTANCE SPEED TOOL BRINGING THIS TO RFD BY 19Z
AND TO ORD BY 20Z. SHORT TERM GUIDANCE CONTINUES TO INDICATE THE
POSSIBILITY OF MVFR CEILINGS LATER THIS EVENING...AND CANNOT RULE
THIS OUT WITH COLDER AIR MOVING ACROSS THE REGION. SO HAVE SHOWED
THIS POSSIBILITY IN THE TAF. VFR OR MVFR CEILINGS WILL NOT BE LONG
LASTING THIS EVENING...WITH THIS AREA OF CLOUD COVER EXPECTED TO
QUICKLY EXIT THE TERMINALS AND ONLY HIGH LEVEL CLOUDS TO THEN MOVE
OVER THE TERMINALS THROUGH THE REMAINDER OF THE FORECAST PERIOD.
WINDS WILL DIMINISH TONIGHT AND EVEN BECOME CALM OR LIGHT AND
VARIABLE AS HIGH PRESSURE MOVES OVERHEAD...BUT THEN INCREASE OUT
OF THE SOUTHEAST BY MID DAY FRIDAY.
RODRIGUEZ
//ORD AND MDW CONFIDENCE...UPDATED 20Z...
* HIGH CONFIDENCE WITH WIND SPEED/DIRECTION.
* LOW MEDIUM CONFIDENCE WITH MVFR POTENTIAL EARLY THIS EVENING.
RODRIGUEZ
//OUTLOOK FOR ORD/MDW FOR 00Z SATURDAY-12Z THURSDAY...UPDATED 12Z...
FRIDAY NIGHT...VFR.
SATURDAY...VFR.
SUNDAY AND MONDAY...MVFR POSSIBLE,
TUESDAY...VFR.
WEDNESDAY...CHANCE SHRA...MVFR POSSIBLE.
MDB
&&
.MARINE...
221 AM CST
THE MAIN FOCUS OF THE FORECAST CONTINUES TO BE THE POTENTIAL FOR
GALE FORCE WINDS LATE FRIDAY NIGHT THROUGH MIDDAY/EARLY AFTERNOON
SATURDAY...MAINLY ACROSS THE NORTH HALF OF THE LAKE.
CURRENTLY...SURFACE LOW PRESSURE CONTINUES TO DEEPEN AS IT MOVES
NORTHWARD INTO EASTERN QUEBEC AND NEWFOUNDLAND. HIGH PRESSURE
RIDGING IS CROSSING LAKE MICHIGAN EARLY THIS MORNING WITH A WEAK
AREA OF LOW PRESSURE OVER WESTERN MINNESOTA AND NORTHWEST IOWA.
THIS LOW WILL MOVE ACROSS NORTHERN LAKE MICHIGAN LATER TODAY AND
THIS EVENING. WINDS HAVE TURNED WEST AND SOUTHWEST THANKS TO THE
PASSAGE OF THE RIDGE AXIS WITH SPEEDS DIMINISHING BUT THEY WILL
INCREASE SOMEWHAT AS THE LOW CROSSES THE AREA LATER TODAY. A
NARROW CORRIDOR OF OFFSHORE SOUTHEASTERLY WINDS IS OCCURRING ALONG
THE MICHIGAN SHORE BUT WILL DIMINISH THROUGH MID MORNING. WINDS
ACROSS FAR NORTHERN LAKE MICHIGAN WILL BE TRICKY AS THE LOW CENTER
IS EXPECTED TO CROSS THIS AREA THIS AFTERNOON. THIS WILL LIKELY
LEAD TO AN EASTERLY SURFACE FLOW OVER FAR NORTHERN LAKE MICHIGAN
LATER THIS MORNING AND THIS AFTERNOON...WHILE THE REST OF THE LAKE
SEES WEST TO SOUTHWEST WINDS. A COOL FRONTAL BOUNDARY WILL CROSS
THE LAKE LATER TODAY TURNING WINDS TO THE NORTHWEST. HIGH PRESSURE
WILL SPREAD IN BEHIND THE FRONT AND STRENGTHEN AS IT CROSSES THE
LAKE FRIDAY BEFORE SHIFTING TO THE EAST. THIS WILL TURN WINDS BACK
TO THE SOUTH BY FRIDAY AFTERNOON WITH RATHER LIGHT SPEEDS.
THE HIGH WILL CONTINUE TO STRENGTHEN AS IT MOVES ACROSS THE NORTHEAST
U.S. WHILE A CLIPPER DROPS SOUTHEAST ACROSS WESTERN ONTARIO JUST
NORTH OF LAKE SUPERIOR SATURDAY. THE PRESSURE GRADIENT WILL TIGHTEN
BETWEEN THESE TWO SYSTEMS LEADING TO STRONG SOUTH TO SOUTHWEST WINDS
LATE FRIDAY NIGHT AND SATURDAY MORNING. THE STRONGEST SPEEDS WILL
OCCUR ACROSS NORTHERN PORTIONS OF THE LAKE. WILL HOLD WINDS TO 30 KT
FOR NOW WITH THE STRONGEST WINDS NORTH...BUT AM CONCERNED THAT AN
INCREASE TO GALES MAY BE NEEDED. THIS SYSTEM IS NOT TOO UNLIKE
SEVERAL WHICH WE SAW EARLIER THIS FALL THAT FEATURED SURFACE LOWS
PASSING TO THE NORTH AND WINDS THAT WERE HIGHER THAN EXPECTED. THIS
MAY NOT BE THE CASE WITH THIS PARTICULAR SYSTEM BUT IT IS WORTH
NOTING GIVEN THAT UNSTABLE CONDITIONS WILL BE IN PLACE ACROSS THE
LAKE SIMILAR TO THESE EARLIER SYSTEMS. A COLD FRONT CROSSES THE
LAKE SATURDAY AFTERNOON ALLOWING WINDS TO DROP OFF SATURDAY
EVENING. ANOTHER AREA OF HIGH PRESSURE WILL MOVE ACROSS THE REGION
SUNDAY AND CONTINUE TO KEEP LIGHTER WINDS IN PLACE THROUGH
TUESDAY. FORECAST CONFIDENCE DROPS OFF BY WEDNESDAY BUT IT DOES
APPEAR THAT A MORE ACTIVE PATTERN WILL BE SETTING UP BRINGING
INCREASING CHANCES FOR STRONGER WINDS.
MDB
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...NONE.
&&
$$
VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE)
FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
WWW.FACEBOOK.COM/US.NATIONALWEATHERSERVICE.CHICAGO.GOV
WWW.TWITTER.COM/NWSCHICAGO
WWW.YOUTUBE.COM/NWSCHICAGO
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
1218 PM CST THU NOV 28 2013
.DISCUSSION...
306 AM CST
THE PRIMARY FORECAST CONCERNS ARE CENTERED ON CLOUD COVER AND
TEMPERATURES THROUGH THE WEEKEND AND THEN CHANCES FOR PRECIPITATION
NEXT WEEK IN WHAT APPEARS TO POSSIBLY BE AN UNSETTLED
PATTERN...ALTHOUGH A HIGH DEGREE OF UNCERTAINTY.
ONE MORE SHORT WAVE IS DIVING SOUTHEAST ACROSS THE GREAT LAKES THIS
THANKSGIVING MORNING IN WHAT HAS BEEN A LITERAL PARADE OF THESE
COLD-AIR-REINFORCING SYSTEMS. A 1017MB SURFACE LOW REFLECTION ACROSS
IA WILL TRANSLATE EAST THIS MORNING AND WEAKEN AS IT DOES SUCH.
MORNING CLOUDS IN PLACE WERE DEVELOPED WITHIN THE WARM AIR ADVECTION
ENVELOPE OF THIS SYSTEM AND AS SUCH HAVE BASES MAINLY ABOVE 5000
FT...SO BELIEVE THEY WILL VACATE BY AFTERNOON ACROSS THE WESTERN AND
SOUTHERN FORECAST AREA GIVEN THE CLOUD-BEARING WIND FLOW. LOW-LEVEL
LAPSE RATES ARE MODESTLY STEEP BEHIND THE SYSTEM WITH SOME MARGINAL
SATURATION FORECAST AT THE TOP OF THE MIXED LAYER...SO LIKELY SOME
SCATTERED STRATOCU WILL CONTINUE. ALL-IN-ALL...EXPECTING SOME SUN
LATE THIS MORNING AND AFTERNOON. GIVEN THE 850MB AND 925MB FORECAST
TEMPS BY THE RAP AND NAM THIS AFTERNOON...WE ONCE AGAIN ARE IN THE
BOTTOM TENTH PERCENTILE FOR THIS TIME OF YEAR. THIS FAVORS HIGHS IN
THE LOWER TO MID 30S. SEE THE CLIMATE DISCUSSION BELOW FOR MORE ON
WHERE THIS STACKS UP FOR THANKSGIVING DAYS.
AS A CANADIAN SURFACE HIGH MOVES OVERHEAD TONIGHT TEMPERATURES
SHOULD RADIATE QUICKLY THIS EVE...EVEN IF IT DOES TAKE A FEW HOURS
AFTER SUNSET TO DIMINISH THE LINGERING STRATOCU. HAVE MID AND EVEN
PATCHY LOWER TEENS IN OUTLYING AREAS. AS THE WIND FIELD OVER LAKE MI
SHIFTS MORE NE TONIGHT IMMEDIATELY AHEAD OF THE HIGH CENTER...A LAKE
PLUME OF AT LEAST CLOUDS LOOKS LIKELY INTO NORTHWEST INDIANA AND
POSSIBLY NORTHEAST ILLINOIS. LAKE-INDUCED EQUILIBRIUM LEVELS AROUND
4500 FT FORECAST BY THE NAM SEEM A LITTLE SHALLOW FOR PRECIP AND ANY
PRONOUNCED CONVERGENCE IS UNLIKELY. HAVE THUS ONLY ADDED A LOW
CHANCE FOR SOME LIGHT SNOW IN NORTHWEST IN/FAR SOUTHEAST COOK COUNTY
LATE TONIGHT AS WELL AS BUMPED UP CLOUD COVER.
A MORE ZONAL PATTERN WILL MOVE OVER BY LATER FRIDAY INTO SATURDAY
BRINGING MODERATING TEMPERATURES. THERE IS A FAIR AMOUNT OF SPREAD
IN THE ENVELOPE OF GUIDANCE SOLUTIONS FOR HOW WARM SATURDAY WILL
BE...AND POTENTIAL CLOUD COVER LIKELY HAS QUITE A BIT TO DO WITH
THAT. THIS TIME OF YEAR SOUTHERLY LOW-LEVEL FLOW AFTER A COLD AIR
MASS CAN READILY BECOME "CONTAMINATED" WITH SATURATION/CLOUDS.
CLIMATOLOGY OF THE 850MB AND 925MB TEMPERATURES WOULD FAVOR MID AND
MAYBE EVEN UPPER 40S...BUT THAT WARM CURRENTLY SEEMS UNLIKELY WITH
AT LEAST SOME POTENTIAL FOR CLOUDS AND NOT THE STRONGEST OF WARM AIR
ADVECTION SIGNALS. THE HEART OF THE SYSTEM IS OVER THE NORTHERN
GREAT LAKES...SO FORCING AND SATURATION REMAINS MINIMAL OVER THE
AREA. SO HAVE NO POPS AT THIS TIME.
NEXT WEEK THE UNCERTAINTY REALLY STARTS TO RAMP UP BY MIDWEEK AFTER
WHAT IS BECOMING A MORE FAVORED DRY SUNDAY AND MONDAY. ALTHOUGH MUCH
LIKE SATURDAY...TEMPERATURE CONFIDENCE IS FAIRLY LOW GIVEN CLOUD
POTENTIAL. IF CLOUDS ARE REMAINING INTO SUNDAY MORNING THEY VERY
WELL COULD STICK AROUND ALL THE WAY THROUGH MONDAY NIGHT AS SURFACE
PRESSURES ARE FORECAST TO BASICALLY REMAIN THE SAME...I.E. LITTLE
ADVECTION. THE LONG ADVERTISED UPPER TROUGH ACROSS THE WEST COAST
LOOKS TO EVOLVE IN THE BEGINNING OF THE WEEK AND FORCE DOWNSTREAM
RIDGING AND SOUTHWEST FLOW ALOFT. THIS TROUGH SHOULD PACK QUITE A
PUNCH OF COLD AIR INTO THE NORTHERN ROCKIES AND PLAINS...BUT THE
MAIN BAROCLINIC ZONE DURING MIDWEEK LOOKS TO REMAIN TO THE NORTHWEST
AND IF THAT IS THE CASE THEN ANY HEAVY WINTER PRECIP SHOULD AS WELL
DURING MIDWEEK...BUT AGAIN CONFIDENCE IS LOW. ENERGY THAT TRANSLATES
EAST FROM THIS TROUGH APPEARS TO BE IN PARTS AND THUS MULTIPLE
CHANCES FOR PRECIP LOOK TO BE THE CASE ACROSS THE GREAT LAKES AND
CORN BELT REGIONS DURING THE DEC 3-8 PERIOD. NIGHTTIME TEMPERATURES
SHOULD BE MORE NEAR NORMAL OR EVEN ABOVE NORMAL GIVEN CLOUD
COVER DURING MIDWEEK...BUT DAYTIME HIGHS COULD BE ANYWHERE IN A
LARGE SPECTRUM OF SOLUTIONS DEPENDING ON STRENGTH OF SOUTHERLY
FLOW AND WHEN LOW PASSAGES OCCUR. THOSE ARE BOTH VARIABLES DIFFICULT
TO LOCK DOWN IN A FORECAST PATTERN OF A BROAD TROUGH IN THE WEST.
MTF
&&
.CLIMATE...
306 AM CST
THE FORECAST HIGH TODAY FOR CHICAGO (O`HARE) IS 33 WHICH WOULD TIE
MULTIPLE THANKSGIVINGS IN THE PAST TWO DECADES FOR A COOL
HIGH...THE LAST BEING 2007. HOWEVER IF THE MERCURY STAYS BELOW
THAT...IT WOULD BE THE COLDEST HIGH TEMPERATURE ON THANKSGIVING IN
CHICAGO SINCE 1989.
SIMILARLY FOR ROCKFORD...THE 31 DEGREE FORECAST HIGH WOULD BE THE
COOLEST THANKSGIVING HIGH SINCE 1995 AND IF IT STAYS BELOW THAT IT
WOULD BE THE COOLEST SINCE 1989.
MTF
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 18Z...
* WIND SHIFT FROM WEST SOUTHWEST TO NORTHWEST BY 20Z.
* VFR CEILINGS EXPECTED THIS AFTERNOON...WITH A CHANCE FOR A BRIEF
PERIOD OF MVFR CEILINGS EARLY THIS EVENING.
RODRIGUEZ
//DISCUSSION...UPDATED 18Z...
AN APPROACHING COLD FRONT WILL PUSH ACROSS THE TERMINALS OVER THE
NEXT 1-2 HOURS WITH WEST SOUTHWEST WINDS TURNING TO THE
NORTHWEST...AND A RETURN OF VFR CEILINGS. THIS CLOUD COVER CAN BE
OBSERVED MOVING SOUTHEAST ACROSS EASTERN IOWA AND SOUTHERN
WISCONSIN...WITH DISTANCE SPEED TOOL BRINGING THIS TO RFD BY 19Z
AND TO ORD BY 20Z. SHORT TERM GUIDANCE CONTINUES TO INDICATE THE
POSSIBILITY OF MVFR CEILINGS LATER THIS EVENING...AND CANNOT RULE
THIS OUT WITH COLDER AIR MOVING ACROSS THE REGION. SO HAVE SHOWED
THIS POSSIBILITY IN THE TAF. VFR OR MVFR CEILINGS WILL NOT BE LONG
LASTING THIS EVENING...WITH THIS AREA OF CLOUD COVER EXPECTED TO
QUICKLY EXIT THE TERMINALS AND ONLY HIGH LEVEL CLOUDS TO THEN MOVE
OVER THE TERMINALS THROUGH THE REMAINDER OF THE FORECAST PERIOD.
WINDS WILL DIMINISH TONIGHT AND EVEN BECOME CALM OR LIGHT AND
VARIABLE AS HIGH PRESSURE MOVES OVERHEAD...BUT THEN INCREASE OUT
OF THE SOUTHEAST BY MID DAY FRIDAY.
RODRIGUEZ
//ORD AND MDW CONFIDENCE...UPDATED 18Z...
* HIGH CONFIDENCE WITH WIND SPEED/DIRECTION.
* LOW MEDIUM CONFIDENCE WITH MVFR POTENTIAL EARLY THIS EVENING.
RODRIGUEZ
//OUTLOOK FOR ORD/MDW FOR 00Z SATURDAY-12Z THURSDAY...UPDATED 12Z...
FRIDAY NIGHT...VFR.
SATURDAY...VFR.
SUNDAY AND MONDAY...MVFR POSSIBLE,
TUESDAY...VFR.
WEDNESDAY...CHANCE SHRA...MVFR POSSIBLE.
MDB
&&
.MARINE...
221 AM CST
THE MAIN FOCUS OF THE FORECAST CONTINUES TO BE THE POTENTIAL FOR
GALE FORCE WINDS LATE FRIDAY NIGHT THROUGH MIDDAY/EARLY AFTERNOON
SATURDAY...MAINLY ACROSS THE NORTH HALF OF THE LAKE.
CURRENTLY...SURFACE LOW PRESSURE CONTINUES TO DEEPEN AS IT MOVES
NORTHWARD INTO EASTERN QUEBEC AND NEWFOUNDLAND. HIGH PRESSURE
RIDGING IS CROSSING LAKE MICHIGAN EARLY THIS MORNING WITH A WEAK
AREA OF LOW PRESSURE OVER WESTERN MINNESOTA AND NORTHWEST IOWA.
THIS LOW WILL MOVE ACROSS NORTHERN LAKE MICHIGAN LATER TODAY AND
THIS EVENING. WINDS HAVE TURNED WEST AND SOUTHWEST THANKS TO THE
PASSAGE OF THE RIDGE AXIS WITH SPEEDS DIMINISHING BUT THEY WILL
INCREASE SOMEWHAT AS THE LOW CROSSES THE AREA LATER TODAY. A
NARROW CORRIDOR OF OFFSHORE SOUTHEASTERLY WINDS IS OCCURRING ALONG
THE MICHIGAN SHORE BUT WILL DIMINISH THROUGH MID MORNING. WINDS
ACROSS FAR NORTHERN LAKE MICHIGAN WILL BE TRICKY AS THE LOW CENTER
IS EXPECTED TO CROSS THIS AREA THIS AFTERNOON. THIS WILL LIKELY
LEAD TO AN EASTERLY SURFACE FLOW OVER FAR NORTHERN LAKE MICHIGAN
LATER THIS MORNING AND THIS AFTERNOON...WHILE THE REST OF THE LAKE
SEES WEST TO SOUTHWEST WINDS. A COOL FRONTAL BOUNDARY WILL CROSS
THE LAKE LATER TODAY TURNING WINDS TO THE NORTHWEST. HIGH PRESSURE
WILL SPREAD IN BEHIND THE FRONT AND STRENGTHEN AS IT CROSSES THE
LAKE FRIDAY BEFORE SHIFTING TO THE EAST. THIS WILL TURN WINDS BACK
TO THE SOUTH BY FRIDAY AFTERNOON WITH RATHER LIGHT SPEEDS.
THE HIGH WILL CONTINUE TO STRENGTHEN AS IT MOVES ACROSS THE NORTHEAST
U.S. WHILE A CLIPPER DROPS SOUTHEAST ACROSS WESTERN ONTARIO JUST
NORTH OF LAKE SUPERIOR SATURDAY. THE PRESSURE GRADIENT WILL TIGHTEN
BETWEEN THESE TWO SYSTEMS LEADING TO STRONG SOUTH TO SOUTHWEST WINDS
LATE FRIDAY NIGHT AND SATURDAY MORNING. THE STRONGEST SPEEDS WILL
OCCUR ACROSS NORTHERN PORTIONS OF THE LAKE. WILL HOLD WINDS TO 30 KT
FOR NOW WITH THE STRONGEST WINDS NORTH...BUT AM CONCERNED THAT AN
INCREASE TO GALES MAY BE NEEDED. THIS SYSTEM IS NOT TOO UNLIKE
SEVERAL WHICH WE SAW EARLIER THIS FALL THAT FEATURED SURFACE LOWS
PASSING TO THE NORTH AND WINDS THAT WERE HIGHER THAN EXPECTED. THIS
MAY NOT BE THE CASE WITH THIS PARTICULAR SYSTEM BUT IT IS WORTH
NOTING GIVEN THAT UNSTABLE CONDITIONS WILL BE IN PLACE ACROSS THE
LAKE SIMILAR TO THESE EARLIER SYSTEMS. A COLD FRONT CROSSES THE
LAKE SATURDAY AFTERNOON ALLOWING WINDS TO DROP OFF SATURDAY
EVENING. ANOTHER AREA OF HIGH PRESSURE WILL MOVE ACROSS THE REGION
SUNDAY AND CONTINUE TO KEEP LIGHTER WINDS IN PLACE THROUGH
TUESDAY. FORECAST CONFIDENCE DROPS OFF BY WEDNESDAY BUT IT DOES
APPEAR THAT A MORE ACTIVE PATTERN WILL BE SETTING UP BRINGING
INCREASING CHANCES FOR STRONGER WINDS.
MDB
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...NONE.
&&
$$
VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE)
FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
WWW.FACEBOOK.COM/US.NATIONALWEATHERSERVICE.CHICAGO.GOV
WWW.TWITTER.COM/NWSCHICAGO
WWW.YOUTUBE.COM/NWSCHICAGO
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
1005 AM CST THU NOV 28 2013
.DISCUSSION...
306 AM CST
THE PRIMARY FORECAST CONCERNS ARE CENTERED ON CLOUD COVER AND
TEMPERATURES THROUGH THE WEEKEND AND THEN CHANCES FOR PRECIPITATION
NEXT WEEK IN WHAT APPEARS TO POSSIBLY BE AN UNSETTLED
PATTERN...ALTHOUGH A HIGH DEGREE OF UNCERTAINTY.
ONE MORE SHORT WAVE IS DIVING SOUTHEAST ACROSS THE GREAT LAKES THIS
THANKSGIVING MORNING IN WHAT HAS BEEN A LITERAL PARADE OF THESE
COLD-AIR-REINFORCING SYSTEMS. A 1017MB SURFACE LOW REFLECTION ACROSS
IA WILL TRANSLATE EAST THIS MORNING AND WEAKEN AS IT DOES SUCH.
MORNING CLOUDS IN PLACE WERE DEVELOPED WITHIN THE WARM AIR ADVECTION
ENVELOPE OF THIS SYSTEM AND AS SUCH HAVE BASES MAINLY ABOVE 5000
FT...SO BELIEVE THEY WILL VACATE BY AFTERNOON ACROSS THE WESTERN AND
SOUTHERN FORECAST AREA GIVEN THE CLOUD-BEARING WIND FLOW. LOW-LEVEL
LAPSE RATES ARE MODESTLY STEEP BEHIND THE SYSTEM WITH SOME MARGINAL
SATURATION FORECAST AT THE TOP OF THE MIXED LAYER...SO LIKELY SOME
SCATTERED STRATOCU WILL CONTINUE. ALL-IN-ALL...EXPECTING SOME SUN
LATE THIS MORNING AND AFTERNOON. GIVEN THE 850MB AND 925MB FORECAST
TEMPS BY THE RAP AND NAM THIS AFTERNOON...WE ONCE AGAIN ARE IN THE
BOTTOM TENTH PERCENTILE FOR THIS TIME OF YEAR. THIS FAVORS HIGHS IN
THE LOWER TO MID 30S. SEE THE CLIMATE DISCUSSION BELOW FOR MORE ON
WHERE THIS STACKS UP FOR THANKSGIVING DAYS.
AS A CANADIAN SURFACE HIGH MOVES OVERHEAD TONIGHT TEMPERATURES
SHOULD RADIATE QUICKLY THIS EVE...EVEN IF IT DOES TAKE A FEW HOURS
AFTER SUNSET TO DIMINISH THE LINGERING STRATOCU. HAVE MID AND EVEN
PATCHY LOWER TEENS IN OUTLYING AREAS. AS THE WIND FIELD OVER LAKE MI
SHIFTS MORE NE TONIGHT IMMEDIATELY AHEAD OF THE HIGH CENTER...A LAKE
PLUME OF AT LEAST CLOUDS LOOKS LIKELY INTO NORTHWEST INDIANA AND
POSSIBLY NORTHEAST ILLINOIS. LAKE-INDUCED EQUILIBRIUM LEVELS AROUND
4500 FT FORECAST BY THE NAM SEEM A LITTLE SHALLOW FOR PRECIP AND ANY
PRONOUNCED CONVERGENCE IS UNLIKELY. HAVE THUS ONLY ADDED A LOW
CHANCE FOR SOME LIGHT SNOW IN NORTHWEST IN/FAR SOUTHEAST COOK COUNTY
LATE TONIGHT AS WELL AS BUMPED UP CLOUD COVER.
A MORE ZONAL PATTERN WILL MOVE OVER BY LATER FRIDAY INTO SATURDAY
BRINGING MODERATING TEMPERATURES. THERE IS A FAIR AMOUNT OF SPREAD
IN THE ENVELOPE OF GUIDANCE SOLUTIONS FOR HOW WARM SATURDAY WILL
BE...AND POTENTIAL CLOUD COVER LIKELY HAS QUITE A BIT TO DO WITH
THAT. THIS TIME OF YEAR SOUTHERLY LOW-LEVEL FLOW AFTER A COLD AIR
MASS CAN READILY BECOME "CONTAMINATED" WITH SATURATION/CLOUDS.
CLIMATOLOGY OF THE 850MB AND 925MB TEMPERATURES WOULD FAVOR MID AND
MAYBE EVEN UPPER 40S...BUT THAT WARM CURRENTLY SEEMS UNLIKELY WITH
AT LEAST SOME POTENTIAL FOR CLOUDS AND NOT THE STRONGEST OF WARM AIR
ADVECTION SIGNALS. THE HEART OF THE SYSTEM IS OVER THE NORTHERN
GREAT LAKES...SO FORCING AND SATURATION REMAINS MINIMAL OVER THE
AREA. SO HAVE NO POPS AT THIS TIME.
NEXT WEEK THE UNCERTAINTY REALLY STARTS TO RAMP UP BY MIDWEEK AFTER
WHAT IS BECOMING A MORE FAVORED DRY SUNDAY AND MONDAY. ALTHOUGH MUCH
LIKE SATURDAY...TEMPERATURE CONFIDENCE IS FAIRLY LOW GIVEN CLOUD
POTENTIAL. IF CLOUDS ARE REMAINING INTO SUNDAY MORNING THEY VERY
WELL COULD STICK AROUND ALL THE WAY THROUGH MONDAY NIGHT AS SURFACE
PRESSURES ARE FORECAST TO BASICALLY REMAIN THE SAME...I.E. LITTLE
ADVECTION. THE LONG ADVERTISED UPPER TROUGH ACROSS THE WEST COAST
LOOKS TO EVOLVE IN THE BEGINNING OF THE WEEK AND FORCE DOWNSTREAM
RIDGING AND SOUTHWEST FLOW ALOFT. THIS TROUGH SHOULD PACK QUITE A
PUNCH OF COLD AIR INTO THE NORTHERN ROCKIES AND PLAINS...BUT THE
MAIN BAROCLINIC ZONE DURING MIDWEEK LOOKS TO REMAIN TO THE NORTHWEST
AND IF THAT IS THE CASE THEN ANY HEAVY WINTER PRECIP SHOULD AS WELL
DURING MIDWEEK...BUT AGAIN CONFIDENCE IS LOW. ENERGY THAT TRANSLATES
EAST FROM THIS TROUGH APPEARS TO BE IN PARTS AND THUS MULTIPLE
CHANCES FOR PRECIP LOOK TO BE THE CASE ACROSS THE GREAT LAKES AND
CORN BELT REGIONS DURING THE DEC 3-8 PERIOD. NIGHTTIME TEMPERATURES
SHOULD BE MORE NEAR NORMAL OR EVEN ABOVE NORMAL GIVEN CLOUD
COVER DURING MIDWEEK...BUT DAYTIME HIGHS COULD BE ANYWHERE IN A
LARGE SPECTRUM OF SOLUTIONS DEPENDING ON STRENGTH OF SOUTHERLY
FLOW AND WHEN LOW PASSAGES OCCUR. THOSE ARE BOTH VARIABLES DIFFICULT
TO LOCK DOWN IN A FORECAST PATTERN OF A BROAD TROUGH IN THE WEST.
MTF
&&
.CLIMATE...
306 AM CST
THE FORECAST HIGH TODAY FOR CHICAGO (O`HARE) IS 33 WHICH WOULD TIE
MULTIPLE THANKSGIVINGS IN THE PAST TWO DECADES FOR A COOL
HIGH...THE LAST BEING 2007. HOWEVER IF THE MERCURY STAYS BELOW
THAT...IT WOULD BE THE COLDEST HIGH TEMPERATURE ON THANKSGIVING IN
CHICAGO SINCE 1989.
SIMILARLY FOR ROCKFORD...THE 31 DEGREE FORECAST HIGH WOULD BE THE
COOLEST THANKSGIVING HIGH SINCE 1995 AND IF IT STAYS BELOW THAT IT
WOULD BE THE COOLEST SINCE 1989.
MTF
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 16Z...
* WIND SHIFT FROM SOUTHWEST TO NORTHWEST TOWARD 20Z.
* VFR EXPECTED TO CONTINUE BUT THERE IS A LOW CHANCE FOR A PERIOD
OF MVFR CIGS LATER THIS AFTERNOON.
MDB/RODRIGUEZ
//DISCUSSION...UPDATED 12Z...
HIGH PRESSURE RIDGING HAS SHIFTED OFF TO THE EAST OF THE TERMINALS
ALLOWING A STEADIER SOUTHERLY FLOW TO SET UP. AN UPPER LEVEL
TROUGH IS CURRENTLY CROSSING THE AREA WITH ASSOCIATED PRECIP
REMAINING NORTHEAST OF THE AREA. VFR CLOUD SHIELD WITH BASES OF
6000-7000 FT CONTINUES TO MOVE EASTWARD WITH THE BACK EDGE OF IT
COMING INTO NORTH CENTRAL ILLINOIS. HAVE GONE AHEAD AND REDUCED
CLOUD COVER OVER THE NEXT FEW HOURS AS SATELLITE SUPPORTS THIS
CLOUD BAND EXITING TO THE EAST OF THE TERMINALS. COVERAGE COULD BE
MUCH LESS THAN THE SCT INCLUDED IN THE TAFS BUT SOME ADDITIONAL
CUMULUS COULD DEVELOP.
SOUTH TO SOUTHWEST WINDS WILL CONTINUE THROUGH THE MORNING THEN
TURN WEST AND THEN NORTHWEST WITH THE PASSAGE OF A COLD FRONTAL
BOUNDARY THIS AFTERNOON. CLOUD COVER TO THE NORTH OF THE AREA
LOOKS TO WORK SOUTHWARD INTO THE AREA LATER THIS AFTERNOON. EXPECT
THE BULK OF THIS TO BE VFR BUT SOME MVFR MAY DEVELOP FOR A BRIEF
PERIOD. WINDS WILL DIMINISH LATER THIS EVENING WHILE TRYING TO
TURN MORE NORTHERLY OVERNIGHT WITH ANY LATE DAY CLOUD COVER
EXITING THE AREA LEAVING LITTLE IN THE WAY OF SKY COVER GOING INTO
FRIDAY MORNING.
MDB
//ORD AND MDW CONFIDENCE...UPDATED 16Z...
* HIGH CONFIDENCE IN WIND FORECAST.
* LOW CONFIDENCE IN MVFR POTENTIAL THIS AFTERNOON.
MDB/RODRIGUEZ
//OUTLOOK FOR ORD/MDW FOR 00Z SATURDAY-12Z THURSDAY...UPDATED 12Z...
FRIDAY NIGHT...VFR.
SATURDAY...VFR.
SUNDAY AND MONDAY...MVFR POSSIBLE,
TUESDAY...VFR.
WEDNESDAY...CHANCE SHRA...MVFR POSSIBLE.
MDB
&&
.MARINE...
221 AM CST
THE MAIN FOCUS OF THE FORECAST CONTINUES TO BE THE POTENTIAL FOR
GALE FORCE WINDS LATE FRIDAY NIGHT THROUGH MIDDAY/EARLY AFTERNOON
SATURDAY...MAINLY ACROSS THE NORTH HALF OF THE LAKE.
CURRENTLY...SURFACE LOW PRESSURE CONTINUES TO DEEPEN AS IT MOVES
NORTHWARD INTO EASTERN QUEBEC AND NEWFOUNDLAND. HIGH PRESSURE
RIDGING IS CROSSING LAKE MICHIGAN EARLY THIS MORNING WITH A WEAK
AREA OF LOW PRESSURE OVER WESTERN MINNESOTA AND NORTHWEST IOWA.
THIS LOW WILL MOVE ACROSS NORTHERN LAKE MICHIGAN LATER TODAY AND
THIS EVENING. WINDS HAVE TURNED WEST AND SOUTHWEST THANKS TO THE
PASSAGE OF THE RIDGE AXIS WITH SPEEDS DIMINISHING BUT THEY WILL
INCREASE SOMEWHAT AS THE LOW CROSSES THE AREA LATER TODAY. A
NARROW CORRIDOR OF OFFSHORE SOUTHEASTERLY WINDS IS OCCURRING ALONG
THE MICHIGAN SHORE BUT WILL DIMINISH THROUGH MID MORNING. WINDS
ACROSS FAR NORTHERN LAKE MICHIGAN WILL BE TRICKY AS THE LOW CENTER
IS EXPECTED TO CROSS THIS AREA THIS AFTERNOON. THIS WILL LIKELY
LEAD TO AN EASTERLY SURFACE FLOW OVER FAR NORTHERN LAKE MICHIGAN
LATER THIS MORNING AND THIS AFTERNOON...WHILE THE REST OF THE LAKE
SEES WEST TO SOUTHWEST WINDS. A COOL FRONTAL BOUNDARY WILL CROSS
THE LAKE LATER TODAY TURNING WINDS TO THE NORTHWEST. HIGH PRESSURE
WILL SPREAD IN BEHIND THE FRONT AND STRENGTHEN AS IT CROSSES THE
LAKE FRIDAY BEFORE SHIFTING TO THE EAST. THIS WILL TURN WINDS BACK
TO THE SOUTH BY FRIDAY AFTERNOON WITH RATHER LIGHT SPEEDS.
THE HIGH WILL CONTINUE TO STRENGTHEN AS IT MOVES ACROSS THE NORTHEAST
U.S. WHILE A CLIPPER DROPS SOUTHEAST ACROSS WESTERN ONTARIO JUST
NORTH OF LAKE SUPERIOR SATURDAY. THE PRESSURE GRADIENT WILL TIGHTEN
BETWEEN THESE TWO SYSTEMS LEADING TO STRONG SOUTH TO SOUTHWEST WINDS
LATE FRIDAY NIGHT AND SATURDAY MORNING. THE STRONGEST SPEEDS WILL
OCCUR ACROSS NORTHERN PORTIONS OF THE LAKE. WILL HOLD WINDS TO 30 KT
FOR NOW WITH THE STRONGEST WINDS NORTH...BUT AM CONCERNED THAT AN
INCREASE TO GALES MAY BE NEEDED. THIS SYSTEM IS NOT TOO UNLIKE
SEVERAL WHICH WE SAW EARLIER THIS FALL THAT FEATURED SURFACE LOWS
PASSING TO THE NORTH AND WINDS THAT WERE HIGHER THAN EXPECTED. THIS
MAY NOT BE THE CASE WITH THIS PARTICULAR SYSTEM BUT IT IS WORTH
NOTING GIVEN THAT UNSTABLE CONDITIONS WILL BE IN PLACE ACROSS THE
LAKE SIMILAR TO THESE EARLIER SYSTEMS. A COLD FRONT CROSSES THE
LAKE SATURDAY AFTERNOON ALLOWING WINDS TO DROP OFF SATURDAY
EVENING. ANOTHER AREA OF HIGH PRESSURE WILL MOVE ACROSS THE REGION
SUNDAY AND CONTINUE TO KEEP LIGHTER WINDS IN PLACE THROUGH
TUESDAY. FORECAST CONFIDENCE DROPS OFF BY WEDNESDAY BUT IT DOES
APPEAR THAT A MORE ACTIVE PATTERN WILL BE SETTING UP BRINGING
INCREASING CHANCES FOR STRONGER WINDS.
MDB
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...NONE.
&&
$$
VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE)
FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
WWW.FACEBOOK.COM/US.NATIONALWEATHERSERVICE.CHICAGO.GOV
WWW.TWITTER.COM/NWSCHICAGO
WWW.YOUTUBE.COM/NWSCHICAGO
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
810 AM CST THU NOV 28 2013
.DISCUSSION...
306 AM CST
THE PRIMARY FORECAST CONCERNS ARE CENTERED ON CLOUD COVER AND
TEMPERATURES THROUGH THE WEEKEND AND THEN CHANCES FOR PRECIPITATION
NEXT WEEK IN WHAT APPEARS TO POSSIBLY BE AN UNSETTLED
PATTERN...ALTHOUGH A HIGH DEGREE OF UNCERTAINTY.
ONE MORE SHORT WAVE IS DIVING SOUTHEAST ACROSS THE GREAT LAKES THIS
THANKSGIVING MORNING IN WHAT HAS BEEN A LITERAL PARADE OF THESE
COLD-AIR-REINFORCING SYSTEMS. A 1017MB SURFACE LOW REFLECTION ACROSS
IA WILL TRANSLATE EAST THIS MORNING AND WEAKEN AS IT DOES SUCH.
MORNING CLOUDS IN PLACE WERE DEVELOPED WITHIN THE WARM AIR ADVECTION
ENVELOPE OF THIS SYSTEM AND AS SUCH HAVE BASES MAINLY ABOVE 5000
FT...SO BELIEVE THEY WILL VACATE BY AFTERNOON ACROSS THE WESTERN AND
SOUTHERN FORECAST AREA GIVEN THE CLOUD-BEARING WIND FLOW. LOW-LEVEL
LAPSE RATES ARE MODESTLY STEEP BEHIND THE SYSTEM WITH SOME MARGINAL
SATURATION FORECAST AT THE TOP OF THE MIXED LAYER...SO LIKELY SOME
SCATTERED STRATOCU WILL CONTINUE. ALL-IN-ALL...EXPECTING SOME SUN
LATE THIS MORNING AND AFTERNOON. GIVEN THE 850MB AND 925MB FORECAST
TEMPS BY THE RAP AND NAM THIS AFTERNOON...WE ONCE AGAIN ARE IN THE
BOTTOM TENTH PERCENTILE FOR THIS TIME OF YEAR. THIS FAVORS HIGHS IN
THE LOWER TO MID 30S. SEE THE CLIMATE DISCUSSION BELOW FOR MORE ON
WHERE THIS STACKS UP FOR THANKSGIVING DAYS.
AS A CANADIAN SURFACE HIGH MOVES OVERHEAD TONIGHT TEMPERATURES
SHOULD RADIATE QUICKLY THIS EVE...EVEN IF IT DOES TAKE A FEW HOURS
AFTER SUNSET TO DIMINISH THE LINGERING STRATOCU. HAVE MID AND EVEN
PATCHY LOWER TEENS IN OUTLYING AREAS. AS THE WIND FIELD OVER LAKE MI
SHIFTS MORE NE TONIGHT IMMEDIATELY AHEAD OF THE HIGH CENTER...A LAKE
PLUME OF AT LEAST CLOUDS LOOKS LIKELY INTO NORTHWEST INDIANA AND
POSSIBLY NORTHEAST ILLINOIS. LAKE-INDUCED EQUILIBRIUM LEVELS AROUND
4500 FT FORECAST BY THE NAM SEEM A LITTLE SHALLOW FOR PRECIP AND ANY
PRONOUNCED CONVERGENCE IS UNLIKELY. HAVE THUS ONLY ADDED A LOW
CHANCE FOR SOME LIGHT SNOW IN NORTHWEST IN/FAR SOUTHEAST COOK COUNTY
LATE TONIGHT AS WELL AS BUMPED UP CLOUD COVER.
A MORE ZONAL PATTERN WILL MOVE OVER BY LATER FRIDAY INTO SATURDAY
BRINGING MODERATING TEMPERATURES. THERE IS A FAIR AMOUNT OF SPREAD
IN THE ENVELOPE OF GUIDANCE SOLUTIONS FOR HOW WARM SATURDAY WILL
BE...AND POTENTIAL CLOUD COVER LIKELY HAS QUITE A BIT TO DO WITH
THAT. THIS TIME OF YEAR SOUTHERLY LOW-LEVEL FLOW AFTER A COLD AIR
MASS CAN READILY BECOME "CONTAMINATED" WITH SATURATION/CLOUDS.
CLIMATOLOGY OF THE 850MB AND 925MB TEMPERATURES WOULD FAVOR MID AND
MAYBE EVEN UPPER 40S...BUT THAT WARM CURRENTLY SEEMS UNLIKELY WITH
AT LEAST SOME POTENTIAL FOR CLOUDS AND NOT THE STRONGEST OF WARM AIR
ADVECTION SIGNALS. THE HEART OF THE SYSTEM IS OVER THE NORTHERN
GREAT LAKES...SO FORCING AND SATURATION REMAINS MINIMAL OVER THE
AREA. SO HAVE NO POPS AT THIS TIME.
NEXT WEEK THE UNCERTAINTY REALLY STARTS TO RAMP UP BY MIDWEEK AFTER
WHAT IS BECOMING A MORE FAVORED DRY SUNDAY AND MONDAY. ALTHOUGH MUCH
LIKE SATURDAY...TEMPERATURE CONFIDENCE IS FAIRLY LOW GIVEN CLOUD
POTENTIAL. IF CLOUDS ARE REMAINING INTO SUNDAY MORNING THEY VERY
WELL COULD STICK AROUND ALL THE WAY THROUGH MONDAY NIGHT AS SURFACE
PRESSURES ARE FORECAST TO BASICALLY REMAIN THE SAME...I.E. LITTLE
ADVECTION. THE LONG ADVERTISED UPPER TROUGH ACROSS THE WEST COAST
LOOKS TO EVOLVE IN THE BEGINNING OF THE WEEK AND FORCE DOWNSTREAM
RIDGING AND SOUTHWEST FLOW ALOFT. THIS TROUGH SHOULD PACK QUITE A
PUNCH OF COLD AIR INTO THE NORTHERN ROCKIES AND PLAINS...BUT THE
MAIN BAROCLINIC ZONE DURING MIDWEEK LOOKS TO REMAIN TO THE NORTHWEST
AND IF THAT IS THE CASE THEN ANY HEAVY WINTER PRECIP SHOULD AS WELL
DURING MIDWEEK...BUT AGAIN CONFIDENCE IS LOW. ENERGY THAT TRANSLATES
EAST FROM THIS TROUGH APPEARS TO BE IN PARTS AND THUS MULTIPLE
CHANCES FOR PRECIP LOOK TO BE THE CASE ACROSS THE GREAT LAKES AND
CORN BELT REGIONS DURING THE DEC 3-8 PERIOD. NIGHTTIME TEMPERATURES
SHOULD BE MORE NEAR NORMAL OR EVEN ABOVE NORMAL GIVEN CLOUD
COVER DURING MIDWEEK...BUT DAYTIME HIGHS COULD BE ANYWHERE IN A
LARGE SPECTRUM OF SOLUTIONS DEPENDING ON STRENGTH OF SOUTHERLY
FLOW AND WHEN LOW PASSAGES OCCUR. THOSE ARE BOTH VARIABLES DIFFICULT
TO LOCK DOWN IN A FORECAST PATTERN OF A BROAD TROUGH IN THE WEST.
MTF
&&
.CLIMATE...
306 AM CST
THE FORECAST HIGH TODAY FOR CHICAGO (O`HARE) IS 33 WHICH WOULD TIE
MULTIPLE THANKSGIVINGS IN THE PAST TWO DECADES FOR A COOL
HIGH...THE LAST BEING 2007. HOWEVER IF THE MERCURY STAYS BELOW
THAT...IT WOULD BE THE COLDEST HIGH TEMPERATURE ON THANKSGIVING IN
CHICAGO SINCE 1989.
SIMILARLY FOR ROCKFORD...THE 31 DEGREE FORECAST HIGH WOULD BE THE
COOLEST THANKSGIVING HIGH SINCE 1995 AND IF IT STAYS BELOW THAT IT
WOULD BE THE COOLEST SINCE 1989.
MTF
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 14Z...
* WIND SHIFT FROM SOUTHWEST TO NORTHWEST TOWARD 20Z.
* VFR EXPECTED TO CONTINUE BUT THERE IS A LOW CHANCE FOR A PERIOD
OF MVFR CIGS LATER THIS AFTERNOON.
MDB/RODRIGUEZ
//DISCUSSION...UPDATED 12Z...
HIGH PRESSURE RIDGING HAS SHIFTED OFF TO THE EAST OF THE TERMINALS
ALLOWING A STEADIER SOUTHERLY FLOW TO SET UP. AN UPPER LEVEL
TROUGH IS CURRENTLY CROSSING THE AREA WITH ASSOCIATED PRECIP
REMAINING NORTHEAST OF THE AREA. VFR CLOUD SHIELD WITH BASES OF
6000-7000 FT CONTINUES TO MOVE EASTWARD WITH THE BACK EDGE OF IT
COMING INTO NORTH CENTRAL ILLINOIS. HAVE GONE AHEAD AND REDUCED
CLOUD COVER OVER THE NEXT FEW HOURS AS SATELLITE SUPPORTS THIS
CLOUD BAND EXITING TO THE EAST OF THE TERMINALS. COVERAGE COULD BE
MUCH LESS THAN THE SCT INCLUDED IN THE TAFS BUT SOME ADDITIONAL
CUMULUS COULD DEVELOP.
SOUTH TO SOUTHWEST WINDS WILL CONTINUE THROUGH THE MORNING THEN
TURN WEST AND THEN NORTHWEST WITH THE PASSAGE OF A COLD FRONTAL
BOUNDARY THIS AFTERNOON. CLOUD COVER TO THE NORTH OF THE AREA
LOOKS TO WORK SOUTHWARD INTO THE AREA LATER THIS AFTERNOON. EXPECT
THE BULK OF THIS TO BE VFR BUT SOME MVFR MAY DEVELOP FOR A BRIEF
PERIOD. WINDS WILL DIMINISH LATER THIS EVENING WHILE TRYING TO
TURN MORE NORTHERLY OVERNIGHT WITH ANY LATE DAY CLOUD COVER
EXITING THE AREA LEAVING LITTLE IN THE WAY OF SKY COVER GOING INTO
FRIDAY MORNING.
MDB
//ORD AND MDW CONFIDENCE...UPDATED 14Z...
* HIGH CONFIDENCE IN WIND FORECAST.
* LOW CONFIDENCE IN MVFR POTENTIAL THIS AFTERNOON.
MDB/RODRIGUEZ
//OUTLOOK FOR ORD/MDW FOR 00Z SATURDAY-12Z THURSDAY...UPDATED 12Z...
FRIDAY NIGHT...VFR.
SATURDAY...VFR.
SUNDAY AND MONDAY...MVFR POSSIBLE,
TUESDAY...VFR.
WEDNESDAY...CHANCE SHRA...MVFR POSSIBLE.
MDB
&&
.MARINE...
221 AM CST
THE MAIN FOCUS OF THE FORECAST CONTINUES TO BE THE POTENTIAL FOR
GALE FORCE WINDS LATE FRIDAY NIGHT THROUGH MIDDAY/EARLY AFTERNOON
SATURDAY...MAINLY ACROSS THE NORTH HALF OF THE LAKE.
CURRENTLY...SURFACE LOW PRESSURE CONTINUES TO DEEPEN AS IT MOVES
NORTHWARD INTO EASTERN QUEBEC AND NEWFOUNDLAND. HIGH PRESSURE
RIDGING IS CROSSING LAKE MICHIGAN EARLY THIS MORNING WITH A WEAK
AREA OF LOW PRESSURE OVER WESTERN MINNESOTA AND NORTHWEST IOWA.
THIS LOW WILL MOVE ACROSS NORTHERN LAKE MICHIGAN LATER TODAY AND
THIS EVENING. WINDS HAVE TURNED WEST AND SOUTHWEST THANKS TO THE
PASSAGE OF THE RIDGE AXIS WITH SPEEDS DIMINISHING BUT THEY WILL
INCREASE SOMEWHAT AS THE LOW CROSSES THE AREA LATER TODAY. A
NARROW CORRIDOR OF OFFSHORE SOUTHEASTERLY WINDS IS OCCURRING ALONG
THE MICHIGAN SHORE BUT WILL DIMINISH THROUGH MID MORNING. WINDS
ACROSS FAR NORTHERN LAKE MICHIGAN WILL BE TRICKY AS THE LOW CENTER
IS EXPECTED TO CROSS THIS AREA THIS AFTERNOON. THIS WILL LIKELY
LEAD TO AN EASTERLY SURFACE FLOW OVER FAR NORTHERN LAKE MICHIGAN
LATER THIS MORNING AND THIS AFTERNOON...WHILE THE REST OF THE LAKE
SEES WEST TO SOUTHWEST WINDS. A COOL FRONTAL BOUNDARY WILL CROSS
THE LAKE LATER TODAY TURNING WINDS TO THE NORTHWEST. HIGH PRESSURE
WILL SPREAD IN BEHIND THE FRONT AND STRENGTHEN AS IT CROSSES THE
LAKE FRIDAY BEFORE SHIFTING TO THE EAST. THIS WILL TURN WINDS BACK
TO THE SOUTH BY FRIDAY AFTERNOON WITH RATHER LIGHT SPEEDS.
THE HIGH WILL CONTINUE TO STRENGTHEN AS IT MOVES ACROSS THE NORTHEAST
U.S. WHILE A CLIPPER DROPS SOUTHEAST ACROSS WESTERN ONTARIO JUST
NORTH OF LAKE SUPERIOR SATURDAY. THE PRESSURE GRADIENT WILL TIGHTEN
BETWEEN THESE TWO SYSTEMS LEADING TO STRONG SOUTH TO SOUTHWEST WINDS
LATE FRIDAY NIGHT AND SATURDAY MORNING. THE STRONGEST SPEEDS WILL
OCCUR ACROSS NORTHERN PORTIONS OF THE LAKE. WILL HOLD WINDS TO 30 KT
FOR NOW WITH THE STRONGEST WINDS NORTH...BUT AM CONCERNED THAT AN
INCREASE TO GALES MAY BE NEEDED. THIS SYSTEM IS NOT TOO UNLIKE
SEVERAL WHICH WE SAW EARLIER THIS FALL THAT FEATURED SURFACE LOWS
PASSING TO THE NORTH AND WINDS THAT WERE HIGHER THAN EXPECTED. THIS
MAY NOT BE THE CASE WITH THIS PARTICULAR SYSTEM BUT IT IS WORTH
NOTING GIVEN THAT UNSTABLE CONDITIONS WILL BE IN PLACE ACROSS THE
LAKE SIMILAR TO THESE EARLIER SYSTEMS. A COLD FRONT CROSSES THE
LAKE SATURDAY AFTERNOON ALLOWING WINDS TO DROP OFF SATURDAY
EVENING. ANOTHER AREA OF HIGH PRESSURE WILL MOVE ACROSS THE REGION
SUNDAY AND CONTINUE TO KEEP LIGHTER WINDS IN PLACE THROUGH
TUESDAY. FORECAST CONFIDENCE DROPS OFF BY WEDNESDAY BUT IT DOES
APPEAR THAT A MORE ACTIVE PATTERN WILL BE SETTING UP BRINGING
INCREASING CHANCES FOR STRONGER WINDS.
MDB
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...NONE.
&&
$$
VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE)
FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
WWW.FACEBOOK.COM/US.NATIONALWEATHERSERVICE.CHICAGO.GOV
WWW.TWITTER.COM/NWSCHICAGO
WWW.YOUTUBE.COM/NWSCHICAGO
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
540 AM CST THU NOV 28 2013
.DISCUSSION...
306 AM CST
THE PRIMARY FORECAST CONCERNS ARE CENTERED ON CLOUD COVER AND
TEMPERATURES THROUGH THE WEEKEND AND THEN CHANCES FOR PRECIPITATION
NEXT WEEK IN WHAT APPEARS TO POSSIBLY BE AN UNSETTLED
PATTERN...ALTHOUGH A HIGH DEGREE OF UNCERTAINTY.
ONE MORE SHORT WAVE IS DIVING SOUTHEAST ACROSS THE GREAT LAKES THIS
THANKSGIVING MORNING IN WHAT HAS BEEN A LITERAL PARADE OF THESE
COLD-AIR-REINFORCING SYSTEMS. A 1017MB SURFACE LOW REFLECTION ACROSS
IA WILL TRANSLATE EAST THIS MORNING AND WEAKEN AS IT DOES SUCH.
MORNING CLOUDS IN PLACE WERE DEVELOPED WITHIN THE WARM AIR ADVECTION
ENVELOPE OF THIS SYSTEM AND AS SUCH HAVE BASES MAINLY ABOVE 5000
FT...SO BELIEVE THEY WILL VACATE BY AFTERNOON ACROSS THE WESTERN AND
SOUTHERN FORECAST AREA GIVEN THE CLOUD-BEARING WIND FLOW. LOW-LEVEL
LAPSE RATES ARE MODESTLY STEEP BEHIND THE SYSTEM WITH SOME MARGINAL
SATURATION FORECAST AT THE TOP OF THE MIXED LAYER...SO LIKELY SOME
SCATTERED STRATOCU WILL CONTINUE. ALL-IN-ALL...EXPECTING SOME SUN
LATE THIS MORNING AND AFTERNOON. GIVEN THE 850MB AND 925MB FORECAST
TEMPS BY THE RAP AND NAM THIS AFTERNOON...WE ONCE AGAIN ARE IN THE
BOTTOM TENTH PERCENTILE FOR THIS TIME OF YEAR. THIS FAVORS HIGHS IN
THE LOWER TO MID 30S. SEE THE CLIMATE DISCUSSION BELOW FOR MORE ON
WHERE THIS STACKS UP FOR THANKSGIVING DAYS.
AS A CANADIAN SURFACE HIGH MOVES OVERHEAD TONIGHT TEMPERATURES
SHOULD RADIATE QUICKLY THIS EVE...EVEN IF IT DOES TAKE A FEW HOURS
AFTER SUNSET TO DIMINISH THE LINGERING STRATOCU. HAVE MID AND EVEN
PATCHY LOWER TEENS IN OUTLYING AREAS. AS THE WIND FIELD OVER LAKE MI
SHIFTS MORE NE TONIGHT IMMEDIATELY AHEAD OF THE HIGH CENTER...A LAKE
PLUME OF AT LEAST CLOUDS LOOKS LIKELY INTO NORTHWEST INDIANA AND
POSSIBLY NORTHEAST ILLINOIS. LAKE-INDUCED EQUILIBRIUM LEVELS AROUND
4500 FT FORECAST BY THE NAM SEEM A LITTLE SHALLOW FOR PRECIP AND ANY
PRONOUNCED CONVERGENCE IS UNLIKELY. HAVE THUS ONLY ADDED A LOW
CHANCE FOR SOME LIGHT SNOW IN NORTHWEST IN/FAR SOUTHEAST COOK COUNTY
LATE TONIGHT AS WELL AS BUMPED UP CLOUD COVER.
A MORE ZONAL PATTERN WILL MOVE OVER BY LATER FRIDAY INTO SATURDAY
BRINGING MODERATING TEMPERATURES. THERE IS A FAIR AMOUNT OF SPREAD
IN THE ENVELOPE OF GUIDANCE SOLUTIONS FOR HOW WARM SATURDAY WILL
BE...AND POTENTIAL CLOUD COVER LIKELY HAS QUITE A BIT TO DO WITH
THAT. THIS TIME OF YEAR SOUTHERLY LOW-LEVEL FLOW AFTER A COLD AIR
MASS CAN READILY BECOME "CONTAMINATED" WITH SATURATION/CLOUDS.
CLIMATOLOGY OF THE 850MB AND 925MB TEMPERATURES WOULD FAVOR MID AND
MAYBE EVEN UPPER 40S...BUT THAT WARM CURRENTLY SEEMS UNLIKELY WITH
AT LEAST SOME POTENTIAL FOR CLOUDS AND NOT THE STRONGEST OF WARM AIR
ADVECTION SIGNALS. THE HEART OF THE SYSTEM IS OVER THE NORTHERN
GREAT LAKES...SO FORCING AND SATURATION REMAINS MINIMAL OVER THE
AREA. SO HAVE NO POPS AT THIS TIME.
NEXT WEEK THE UNCERTAINTY REALLY STARTS TO RAMP UP BY MIDWEEK AFTER
WHAT IS BECOMING A MORE FAVORED DRY SUNDAY AND MONDAY. ALTHOUGH MUCH
LIKE SATURDAY...TEMPERATURE CONFIDENCE IS FAIRLY LOW GIVEN CLOUD
POTENTIAL. IF CLOUDS ARE REMAINING INTO SUNDAY MORNING THEY VERY
WELL COULD STICK AROUND ALL THE WAY THROUGH MONDAY NIGHT AS SURFACE
PRESSURES ARE FORECAST TO BASICALLY REMAIN THE SAME...I.E. LITTLE
ADVECTION. THE LONG ADVERTISED UPPER TROUGH ACROSS THE WEST COAST
LOOKS TO EVOLVE IN THE BEGINNING OF THE WEEK AND FORCE DOWNSTREAM
RIDGING AND SOUTHWEST FLOW ALOFT. THIS TROUGH SHOULD PACK QUITE A
PUNCH OF COLD AIR INTO THE NORTHERN ROCKIES AND PLAINS...BUT THE
MAIN BAROCLINIC ZONE DURING MIDWEEK LOOKS TO REMAIN TO THE NORTHWEST
AND IF THAT IS THE CASE THEN ANY HEAVY WINTER PRECIP SHOULD AS WELL
DURING MIDWEEK...BUT AGAIN CONFIDENCE IS LOW. ENERGY THAT TRANSLATES
EAST FROM THIS TROUGH APPEARS TO BE IN PARTS AND THUS MULTIPLE
CHANCES FOR PRECIP LOOK TO BE THE CASE ACROSS THE GREAT LAKES AND
CORN BELT REGIONS DURING THE DEC 3-8 PERIOD. NIGHTTIME TEMPERATURES
SHOULD BE MORE NEAR NORMAL OR EVEN ABOVE NORMAL GIVEN CLOUD
COVER DURING MIDWEEK...BUT DAYTIME HIGHS COULD BE ANYWHERE IN A
LARGE SPECTRUM OF SOLUTIONS DEPENDING ON STRENGTH OF SOUTHERLY
FLOW AND WHEN LOW PASSAGES OCCUR. THOSE ARE BOTH VARIABLES DIFFICULT
TO LOCK DOWN IN A FORECAST PATTERN OF A BROAD TROUGH IN THE WEST.
MTF
&&
.CLIMATE...
306 AM CST
THE FORECAST HIGH TODAY FOR CHICAGO (O`HARE) IS 33 WHICH WOULD TIE
MULTIPLE THANKSGIVINGS IN THE PAST TWO DECADES FOR A COOL
HIGH...THE LAST BEING 2007. HOWEVER IF THE MERCURY STAYS BELOW
THAT...IT WOULD BE THE COLDEST HIGH TEMPERATURE ON THANKSGIVING IN
CHICAGO SINCE 1989.
SIMILARLY FOR ROCKFORD...THE 31 DEGREE FORECAST HIGH WOULD BE THE
COOLEST THANKSGIVING HIGH SINCE 1995 AND IF IT STAYS BELOW THAT IT
WOULD BE THE COOLEST SINCE 1989.
MTF
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 12Z...
* WINDS SHIFT FROM SOUTHWEST TO NORTHWEST TOWARD 20Z.
* VFR EXPECTED TO CONTINUE BUT THERE IS A LOW CHANCE FOR A PERIOD
OF MVFR CIGS LATER THIS AFTERNOON.
MDB
//DISCUSSION...UPDATED 12Z...
HIGH PRESSURE RIDGING HAS SHIFTED OFF TO THE EAST OF THE TERMINALS
ALLOWING A STEADIER SOUTHERLY FLOW TO SET UP. AN UPPER LEVEL
TROUGH IS CURRENTLY CROSSING THE AREA WITH ASSOCIATED PRECIP
REMAINING NORTHEAST OF THE AREA. VFR CLOUD SHIELD WITH BASES OF
6000-7000 FT CONTINUES TO MOVE EASTWARD WITH THE BACK EDGE OF IT
COMING INTO NORTH CENTRAL ILLINOIS. HAVE GONE AHEAD AND REDUCED
CLOUD COVER OVER THE NEXT FEW HOURS AS SATELLITE SUPPORTS THIS
CLOUD BAND EXITING TO THE EAST OF THE TERMINALS. COVERAGE COULD BE
MUCH LESS THAN THE SCT INCLUDED IN THE TAFS BUT SOME ADDITIONAL
CUMULUS COULD DEVELOP.
SOUTH TO SOUTHWEST WINDS WILL CONTINUE THROUGH THE MORNING THEN
TURN WEST AND THEN NORTHWEST WITH THE PASSAGE OF A COLD FRONTAL
BOUNDARY THIS AFTERNOON. CLOUD COVER TO THE NORTH OF THE AREA
LOOKS TO WORK SOUTHWARD INTO THE AREA LATER THIS AFTERNOON. EXPECT
THE BULK OF THIS TO BE VFR BUT SOME MVFR MAY DEVELOP FOR A BRIEF
PERIOD. WINDS WILL DIMINISH LATER THIS EVENING WHILE TRYING TO
TURN MORE NORTHERLY OVERNIGHT WITH ANY LATE DAY CLOUD COVER
EXITING THE AREA LEAVING LITTLE IN THE WAY OF SKY COVER GOING INTO
FRIDAY MORNING.
MDB
//ORD AND MDW CONFIDENCE...UPDATED 12Z...
* HIGH CONFIDENCE IN WIND FORECAST.
* LOW CONFIDENCE IN MVFR POTENTIAL THIS AFTERNOON.
MDB
//OUTLOOK FOR ORD/MDW FOR 00Z SATURDAY-12Z THURSDAY...UPDATED 12Z...
FRIDAY NIGHT...VFR.
SATURDAY...VFR.
SUNDAY AND MONDAY...MVFR POSSIBLE,
TUESDAY...VFR.
WEDNESDAY...CHANCE SHRA...MVFR POSSIBLE.
MDB
&&
.MARINE...
221 AM CST
THE MAIN FOCUS OF THE FORECAST CONTINUES TO BE THE POTENTIAL FOR
GALE FORCE WINDS LATE FRIDAY NIGHT THROUGH MIDDAY/EARLY AFTERNOON
SATURDAY...MAINLY ACROSS THE NORTH HALF OF THE LAKE.
CURRENTLY...SURFACE LOW PRESSURE CONTINUES TO DEEPEN AS IT MOVES
NORTHWARD INTO EASTERN QUEBEC AND NEWFOUNDLAND. HIGH PRESSURE
RIDGING IS CROSSING LAKE MICHIGAN EARLY THIS MORNING WITH A WEAK
AREA OF LOW PRESSURE OVER WESTERN MINNESOTA AND NORTHWEST IOWA.
THIS LOW WILL MOVE ACROSS NORTHERN LAKE MICHIGAN LATER TODAY AND
THIS EVENING. WINDS HAVE TURNED WEST AND SOUTHWEST THANKS TO THE
PASSAGE OF THE RIDGE AXIS WITH SPEEDS DIMINISHING BUT THEY WILL
INCREASE SOMEWHAT AS THE LOW CROSSES THE AREA LATER TODAY. A
NARROW CORRIDOR OF OFFSHORE SOUTHEASTERLY WINDS IS OCCURRING ALONG
THE MICHIGAN SHORE BUT WILL DIMINISH THROUGH MID MORNING. WINDS
ACROSS FAR NORTHERN LAKE MICHIGAN WILL BE TRICKY AS THE LOW CENTER
IS EXPECTED TO CROSS THIS AREA THIS AFTERNOON. THIS WILL LIKELY
LEAD TO AN EASTERLY SURFACE FLOW OVER FAR NORTHERN LAKE MICHIGAN
LATER THIS MORNING AND THIS AFTERNOON...WHILE THE REST OF THE LAKE
SEES WEST TO SOUTHWEST WINDS. A COOL FRONTAL BOUNDARY WILL CROSS
THE LAKE LATER TODAY TURNING WINDS TO THE NORTHWEST. HIGH PRESSURE
WILL SPREAD IN BEHIND THE FRONT AND STRENGTHEN AS IT CROSSES THE
LAKE FRIDAY BEFORE SHIFTING TO THE EAST. THIS WILL TURN WINDS BACK
TO THE SOUTH BY FRIDAY AFTERNOON WITH RATHER LIGHT SPEEDS.
THE HIGH WILL CONTINUE TO STRENGTHEN AS IT MOVES ACROSS THE NORTHEAST
U.S. WHILE A CLIPPER DROPS SOUTHEAST ACROSS WESTERN ONTARIO JUST
NORTH OF LAKE SUPERIOR SATURDAY. THE PRESSURE GRADIENT WILL TIGHTEN
BETWEEN THESE TWO SYSTEMS LEADING TO STRONG SOUTH TO SOUTHWEST WINDS
LATE FRIDAY NIGHT AND SATURDAY MORNING. THE STRONGEST SPEEDS WILL
OCCUR ACROSS NORTHERN PORTIONS OF THE LAKE. WILL HOLD WINDS TO 30 KT
FOR NOW WITH THE STRONGEST WINDS NORTH...BUT AM CONCERNED THAT AN
INCREASE TO GALES MAY BE NEEDED. THIS SYSTEM IS NOT TOO UNLIKE
SEVERAL WHICH WE SAW EARLIER THIS FALL THAT FEATURED SURFACE LOWS
PASSING TO THE NORTH AND WINDS THAT WERE HIGHER THAN EXPECTED. THIS
MAY NOT BE THE CASE WITH THIS PARTICULAR SYSTEM BUT IT IS WORTH
NOTING GIVEN THAT UNSTABLE CONDITIONS WILL BE IN PLACE ACROSS THE
LAKE SIMILAR TO THESE EARLIER SYSTEMS. A COLD FRONT CROSSES THE
LAKE SATURDAY AFTERNOON ALLOWING WINDS TO DROP OFF SATURDAY
EVENING. ANOTHER AREA OF HIGH PRESSURE WILL MOVE ACROSS THE REGION
SUNDAY AND CONTINUE TO KEEP LIGHTER WINDS IN PLACE THROUGH
TUESDAY. FORECAST CONFIDENCE DROPS OFF BY WEDNESDAY BUT IT DOES
APPEAR THAT A MORE ACTIVE PATTERN WILL BE SETTING UP BRINGING
INCREASING CHANCES FOR STRONGER WINDS.
MDB
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...NONE.
&&
$$
VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE)
FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
WWW.FACEBOOK.COM/US.NATIONALWEATHERSERVICE.CHICAGO.GOV
WWW.TWITTER.COM/NWSCHICAGO
WWW.YOUTUBE.COM/NWSCHICAGO
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
310 AM CST THU NOV 28 2013
.DISCUSSION...
306 AM CST
THE PRIMARY FORECAST CONCERNS ARE CENTERED ON CLOUD COVER AND
TEMPERATURES THROUGH THE WEEKEND AND THEN CHANCES FOR PRECIPITATION
NEXT WEEK IN WHAT APPEARS TO POSSIBLY BE AN UNSETTLED
PATTERN...ALTHOUGH A HIGH DEGREE OF UNCERTAINTY.
ONE MORE SHORT WAVE IS DIVING SOUTHEAST ACROSS THE GREAT LAKES THIS
THANKSGIVING MORNING IN WHAT HAS BEEN A LITERAL PARADE OF THESE
COLD-AIR-REINFORCING SYSTEMS. A 1017MB SURFACE LOW REFLECTION ACROSS
IA WILL TRANSLATE EAST THIS MORNING AND WEAKEN AS IT DOES SUCH.
MORNING CLOUDS IN PLACE WERE DEVELOPED WITHIN THE WARM AIR ADVECTION
ENVELOPE OF THIS SYSTEM AND AS SUCH HAVE BASES MAINLY ABOVE 5000
FT...SO BELIEVE THEY WILL VACATE BY AFTERNOON ACROSS THE WESTERN AND
SOUTHERN FORECAST AREA GIVEN THE CLOUD-BEARING WIND FLOW. LOW-LEVEL
LAPSE RATES ARE MODESTLY STEEP BEHIND THE SYSTEM WITH SOME MARGINAL
SATURATION FORECAST AT THE TOP OF THE MIXED LAYER...SO LIKELY SOME
SCATTERED STRATOCU WILL CONTINUE. ALL-IN-ALL...EXPECTING SOME SUN
LATE THIS MORNING AND AFTERNOON. GIVEN THE 850MB AND 925MB FORECAST
TEMPS BY THE RAP AND NAM THIS AFTERNOON...WE ONCE AGAIN ARE IN THE
BOTTOM TENTH PERCENTILE FOR THIS TIME OF YEAR. THIS FAVORS HIGHS IN
THE LOWER TO MID 30S. SEE THE CLIMATE DISCUSSION BELOW FOR MORE ON
WHERE THIS STACKS UP FOR THANKSGIVING DAYS.
AS A CANADIAN SURFACE HIGH MOVES OVERHEAD TONIGHT TEMPERATURES
SHOULD RADIATE QUICKLY THIS EVE...EVEN IF IT DOES TAKE A FEW HOURS
AFTER SUNSET TO DIMINISH THE LINGERING STRATOCU. HAVE MID AND EVEN
PATCHY LOWER TEENS IN OUTLYING AREAS. AS THE WIND FIELD OVER LAKE MI
SHIFTS MORE NE TONIGHT IMMEDIATELY AHEAD OF THE HIGH CENTER...A LAKE
PLUME OF AT LEAST CLOUDS LOOKS LIKELY INTO NORTHWEST INDIANA AND
POSSIBLY NORTHEAST ILLINOIS. LAKE-INDUCED EQUILIBRIUM LEVELS AROUND
4500 FT FORECAST BY THE NAM SEEM A LITTLE SHALLOW FOR PRECIP AND ANY
PRONOUNCED CONVERGENCE IS UNLIKELY. HAVE THUS ONLY ADDED A LOW
CHANCE FOR SOME LIGHT SNOW IN NORTHWEST IN/FAR SOUTHEAST COOK COUNTY
LATE TONIGHT AS WELL AS BUMPED UP CLOUD COVER.
A MORE ZONAL PATTERN WILL MOVE OVER BY LATER FRIDAY INTO SATURDAY
BRINGING MODERATING TEMPERATURES. THERE IS A FAIR AMOUNT OF SPREAD
IN THE ENVELOPE OF GUIDANCE SOLUTIONS FOR HOW WARM SATURDAY WILL
BE...AND POTENTIAL CLOUD COVER LIKELY HAS QUITE A BIT TO DO WITH
THAT. THIS TIME OF YEAR SOUTHERLY LOW-LEVEL FLOW AFTER A COLD AIR
MASS CAN READILY BECOME "CONTAMINATED" WITH SATURATION/CLOUDS.
CLIMATOLOGY OF THE 850MB AND 925MB TEMPERATURES WOULD FAVOR MID AND
MAYBE EVEN UPPER 40S...BUT THAT WARM CURRENTLY SEEMS UNLIKELY WITH
AT LEAST SOME POTENTIAL FOR CLOUDS AND NOT THE STRONGEST OF WARM AIR
ADVECTION SIGNALS. THE HEART OF THE SYSTEM IS OVER THE NORTHERN
GREAT LAKES...SO FORCING AND SATURATION REMAINS MINIMAL OVER THE
AREA. SO HAVE NO POPS AT THIS TIME.
NEXT WEEK THE UNCERTAINTY REALLY STARTS TO RAMP UP BY MIDWEEK AFTER
WHAT IS BECOMING A MORE FAVORED DRY SUNDAY AND MONDAY. ALTHOUGH MUCH
LIKE SATURDAY...TEMPERATURE CONFIDENCE IS FAIRLY LOW GIVEN CLOUD
POTENTIAL. IF CLOUDS ARE REMAINING INTO SUNDAY MORNING THEY VERY
WELL COULD STICK AROUND ALL THE WAY THROUGH MONDAY NIGHT AS SURFACE
PRESSURES ARE FORECAST TO BASICALLY REMAIN THE SAME...I.E. LITTLE
ADVECTION. THE LONG ADVERTISED UPPER TROUGH ACROSS THE WEST COAST
LOOKS TO EVOLVE IN THE BEGINNING OF THE WEEK AND FORCE DOWNSTREAM
RIDGING AND SOUTHWEST FLOW ALOFT. THIS TROUGH SHOULD PACK QUITE A
PUNCH OF COLD AIR INTO THE NORTHERN ROCKIES AND PLAINS...BUT THE
MAIN BAROCLINIC ZONE DURING MIDWEEK LOOKS TO REMAIN TO THE NORTHWEST
AND IF THAT IS THE CASE THEN ANY HEAVY WINTER PRECIP SHOULD AS WELL
DURING MIDWEEK...BUT AGAIN CONFIDENCE IS LOW. ENERGY THAT TRANSLATES
EAST FROM THIS TROUGH APPEARS TO BE IN PARTS AND THUS MULTIPLE
CHANCES FOR PRECIP LOOK TO BE THE CASE ACROSS THE GREAT LAKES AND
CORN BELT REGIONS DURING THE DEC 3-8 PERIOD. NIGHTTIME TEMPERATURES
SHOULD BE MORE NEAR NORMAL OR EVEN ABOVE NORMAL GIVEN CLOUD
COVER DURING MIDWEEK...BUT DAYTIME HIGHS COULD BE ANYWHERE IN A
LARGE SPECTRUM OF SOLUTIONS DEPENDING ON STRENGTH OF SOUTHERLY
FLOW AND WHEN LOW PASSAGES OCCUR. THOSE ARE BOTH VARIABLES DIFFICULT
TO LOCK DOWN IN A FORECAST PATTERN OF A BROAD TROUGH IN THE WEST.
MTF
&&
.CLIMATE...
306 AM CST
THE FORECAST HIGH TODAY FOR CHICAGO (O`HARE) IS 33 WHICH WOULD TIE
MULTIPLE THANKSGIVINGS IN THE PAST TWO DECADES FOR A COOL
HIGH...THE LAST BEING 2007. HOWEVER IF THE MERCURY STAYS BELOW
THAT...IT WOULD BE THE COLDEST HIGH TEMPERATURE ON THANKSGIVING IN
CHICAGO SINCE 1989.
SIMILARLY FOR ROCKFORD...THE 31 DEGREE FORECAST HIGH WOULD BE THE
COOLEST THANKSGIVING HIGH SINCE 1995 AND IF IT STAYS BELOW THAT IT
WOULD BE THE COOLEST SINCE 1989.
MTF
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 09Z...
* WIND SHIFT FROM SOUTHWEST TO NORTHWEST TOWARD 21Z WITH COLD
FRONTAL PASSAGE.
* CHANCE FOR BRIEF PERIOD OF MVFR CIGS MID TO LATE AFTERNOON.
MDB
//DISCUSSION...UPDATED 06Z...
HIGH PRESSURE RIDGING IS CROSSING THE AREA TONIGHT ALLOWING FOR
LIGHT SOUTHWEST WINDS TO SET UP ACROSS THE TERMINALS. WINDS WILL
LIKELY TURN MORE TO THE SOUTH LATER TONIGHT AS THE RIDGE SHIFTS
EAST AND A WEAK LOW APPROACHES FROM THE WEST. AN UPPER LEVEL
TROUGH WILL PASS NORTH OF THE AREA THROUGH THE MORNING BUT
ASSOCIATED MVFR CIGS AND SNOW SHOWERS WILL REMAIN NORTH OF THE
TERMINALS. BEYOND THAT...A COLD FRONT WILL BE DRAGGED ACROSS THE
AREA WITH THE SURFACE LOW WHICH WILL TURN WINDS TO THE NORTHWEST
DURING THE EARLY TO MID AFTERNOON HOURS. THERE WILL BE AT LEAST
SOME CHANCE FOR A BAND OF MVFR CIGS TO ACCOMPANY THE FRONTAL
PASSAGE SO WILL NEED TO MONITOR THE EXTENT SHOULD IT DEVELOP
HOWEVER THE DURATION LOOKS TO BE RATHER SHORT IF IT DOES. HIGH
PRESSURE WILL THEN MOVE IN INTO FRIDAY MORNING ALLOWING FOR LIGHT
NORTHERLY WINDS.
MDB
//ORD AND MDW CONFIDENCE...UPDATED 09Z...
* HIGH CONFIDENCE IN WIND FORECAST.
* LOW-MEDIUM CONFIDENCE THAT SOME MVFR CIGS WILL DEVELOP DURING
THE AFTERNOON.
MDB
//OUTLOOK FOR ORD/MDW FOR 12Z FRIDAY-12Z WEDNESDAY...UPDATED 00Z...
FRIDAY AND SATURDAY...VFR.
SUNDAY AND MONDAY...MVFR CIG POSSIBLE.
TUESDAY...VFR.
ALLSOPP
&&
.MARINE...
221 AM CST
THE MAIN FOCUS OF THE FORECAST CONTINUES TO BE THE POTENTIAL FOR
GALE FORCE WINDS LATE FRIDAY NIGHT THROUGH MIDDAY/EARLY AFTERNOON
SATURDAY...MAINLY ACROSS THE NORTH HALF OF THE LAKE.
CURRENTLY...SURFACE LOW PRESSURE CONTINUES TO DEEPEN AS IT MOVES
NORTHWARD INTO EASTERN QUEBEC AND NEWFOUNDLAND. HIGH PRESSURE
RIDGING IS CROSSING LAKE MICHIGAN EARLY THIS MORNING WITH A WEAK
AREA OF LOW PRESSURE OVER WESTERN MINNESOTA AND NORTHWEST IOWA.
THIS LOW WILL MOVE ACROSS NORTHERN LAKE MICHIGAN LATER TODAY AND
THIS EVENING. WINDS HAVE TURNED WEST AND SOUTHWEST THANKS TO THE
PASSAGE OF THE RIDGE AXIS WITH SPEEDS DIMINISHING BUT THEY WILL
INCREASE SOMEWHAT AS THE LOW CROSSES THE AREA LATER TODAY. A
NARROW CORRIDOR OF OFFSHORE SOUTHEASTERLY WINDS IS OCCURRING ALONG
THE MICHIGAN SHORE BUT WILL DIMINISH THROUGH MID MORNING. WINDS
ACROSS FAR NORTHERN LAKE MICHIGAN WILL BE TRICKY AS THE LOW CENTER
IS EXPECTED TO CROSS THIS AREA THIS AFTERNOON. THIS WILL LIKELY
LEAD TO AN EASTERLY SURFACE FLOW OVER FAR NORTHERN LAKE MICHIGAN
LATER THIS MORNING AND THIS AFTERNOON...WHILE THE REST OF THE LAKE
SEES WEST TO SOUTHWEST WINDS. A COOL FRONTAL BOUNDARY WILL CROSS
THE LAKE LATER TODAY TURNING WINDS TO THE NORTHWEST. HIGH PRESSURE
WILL SPREAD IN BEHIND THE FRONT AND STRENGTHEN AS IT CROSSES THE
LAKE FRIDAY BEFORE SHIFTING TO THE EAST. THIS WILL TURN WINDS BACK
TO THE SOUTH BY FRIDAY AFTERNOON WITH RATHER LIGHT SPEEDS.
THE HIGH WILL CONTINUE TO STRENGTHEN AS IT MOVES ACROSS THE NORTHEAST
U.S. WHILE A CLIPPER DROPS SOUTHEAST ACROSS WESTERN ONTARIO JUST
NORTH OF LAKE SUPERIOR SATURDAY. THE PRESSURE GRADIENT WILL TIGHTEN
BETWEEN THESE TWO SYSTEMS LEADING TO STRONG SOUTH TO SOUTHWEST WINDS
LATE FRIDAY NIGHT AND SATURDAY MORNING. THE STRONGEST SPEEDS WILL
OCCUR ACROSS NORTHERN PORTIONS OF THE LAKE. WILL HOLD WINDS TO 30 KT
FOR NOW WITH THE STRONGEST WINDS NORTH...BUT AM CONCERNED THAT AN
INCREASE TO GALES MAY BE NEEDED. THIS SYSTEM IS NOT TOO UNLIKE
SEVERAL WHICH WE SAW EARLIER THIS FALL THAT FEATURED SURFACE LOWS
PASSING TO THE NORTH AND WINDS THAT WERE HIGHER THAN EXPECTED. THIS
MAY NOT BE THE CASE WITH THIS PARTICULAR SYSTEM BUT IT IS WORTH
NOTING GIVEN THAT UNSTABLE CONDITIONS WILL BE IN PLACE ACROSS THE
LAKE SIMILAR TO THESE EARLIER SYSTEMS. A COLD FRONT CROSSES THE
LAKE SATURDAY AFTERNOON ALLOWING WINDS TO DROP OFF SATURDAY
EVENING. ANOTHER AREA OF HIGH PRESSURE WILL MOVE ACROSS THE REGION
SUNDAY AND CONTINUE TO KEEP LIGHTER WINDS IN PLACE THROUGH
TUESDAY. FORECAST CONFIDENCE DROPS OFF BY WEDNESDAY BUT IT DOES
APPEAR THAT A MORE ACTIVE PATTERN WILL BE SETTING UP BRINGING
INCREASING CHANCES FOR STRONGER WINDS.
MDB
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...SMALL CRAFT ADVISORY...NEARSHORE WATERS
UNTIL 4 AM THURSDAY.
&&
$$
VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE)
FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
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WWW.TWITTER.COM/NWSCHICAGO
WWW.YOUTUBE.COM/NWSCHICAGO
AREA FORECAST DISCUSSION
NWS QUAD CITIES IA IL
314 PM CST THU NOV 28 2013
.SYNOPSIS...
ISSUED AT 218 PM CST THU NOV 28 2013
A WEAK SURFACE LOW MOVED EASTWARD INTO SOUTHERN LAKE MICHIGAN
DURING THE DAY ON THURSDAY WITH A COLD FRONT STRETCHING SOUTHWESTWARD
TO KSTL TO KJLN IN SOUTHWEST MISSOURI. SURFACE HIGH SAT OVER
EASTERN NORTH DAKOTA. STRATUS ALONG THE SOUTH AND WEST SIDES OF
THE HIGH PRESSURE HAS SLOWLY DISSIPATED THROUGH THE DAY. TEMPERATURES
WERE IN THE UPPER 20S IN NORTHWEST ILLINOIS TO THE LOWER 40S IN
WEST CENTRAL ILLINOIS.
A CHANGE IN THE 500 HPA PATTERN WILL OCCUR OVER
THE NEXT SEVEN DAYS AS WE GO FROM THE CURRENT NORTHWEST FLOW ALOFT
TO A MORE ZONAL FLOW WHICH WILL CONTINUE INTO EARLY NEXT WEEK.
THIS WILL RESULT IN SLOWLY MODERATING TEMPERATURES AS THE COLD AIR
OF THE LAST WEEK RETREATS NORTHWARD.
&&
.SHORT TERM...(THIS EVENING THROUGH FRIDAY)
ISSUED AT 218 PM CST THU NOV 28 2013
MODELS ARE IN GOOD OVERALL AGREEMENT WITH THE NAM/RAP BEING AN
OUTLIER WITH LOW LEVEL MOISTURE IN PLACE ACROSS THE REGION. THE
MAIN FORECAST CONCERNS WILL BE THE POTENTIAL FOR CLOUD COVER
OVERNIGHT INTO FRIDAY AS WELL AS TEMPERATURES ON FRIDAY.
HIGH PRESSURE IS FORECAST TO BUILD SOUTHEASTWARD OVERNIGHT AND BE
CENTERED ALONG THE IOWA AND ILLINOIS BORDER BY 12 UTC ON FRIDAY. AN
EXTENSIVE STRATUS DECK DEVELOPED ON THE SOUTH AND WEST SIDES OF
THE HIGH PRESSURE THIS MORNING WITH A STRONG INVERSION IN PLACE
ACROSS THE UPPER MIDWEST AND NORTHERN PLAINS. THE 12 UTC SOUNDINGS
AT KBIS AND KABR SHOWED EXTENSIVE LOW LEVEL MOISTURE IN PLACE. THE
ECMWF...GFS... AND GEM CONTINUE TO SHOW A DRIER INVERSION IN PLACE
ACROSS THE REGION OVERNIGHT WHILE THE NAM AND RAP SHOW MORE
MOISTURE IN THE LOWER LEVELS OF THE ATMOSPHERE BUT NOT TO THE
EXTENT THAT EXISTED AT KBIS AND KABR THIS MORNING. THEREFORE I AM
NOT ANTICIPATING THE FORMATION OF NEW STRATUS TONIGHT SO GOING
WITH CLEAR SKIES TONIGHT. A GOOD RADIATIONAL COOLING NIGHT AND
EXPECT TEMPERATURES TO FALL QUICKLY THIS EVENING.
HIGH PRESSURE IS FORECAST TO SHIFT EASTWARD DURING THE DAY ON
FRIDAY WITH WINDS VEERING TO THE SOUTHEAST DURING THE AFTERNOON HOURS.
850 HPA TEMPERATURES WARM FROM -4 TO -10*C TODAY TO 0 TO -4*C ON
FRIDAY. HAVE WARMED TEMPERATURES UP BY A COUPLE OF DEGREES BUT MID
LEVEL CLOUDINESS WILL BE ON THE INCREASE TOMORROW AHEAD OF ANOTHER
WAVE THAT WILL ARRIVE ON SATURDAY. THE INCREASING CLOUDS MAY HELP
TO KEEP TEMPERATURES FROM WARMING AS THEY DID TODAY.
.LONG TERM...(FRIDAY NIGHT THROUGH THURSDAY)
ISSUED AT 218 PM CST THU NOV 28 2013
FRIDAY NIGHT...WEAK NORTHERN STREAM CLIPPER WILL CONTINUE MOVING TO
GREAT LAKES BY SATURDAY MORNING. OVERNIGHT LOW TEMPERATURES WILL BE
IN THE 20S.
SATURDAY AND SUNDAY...TEMPERATURES WILL RANGE NEAR OR SLIGHTLY ABOVE
NORMAL ON SATURDAY BEFORE A WEAK SURFACE TROF CROSSES THE AREA
SWITCHING THE WIND TO THE WEST NORTHWEST LATE IN THE DAY. WITH
LIMITED MOISTURE THIS TROF PASSAGE WILL BE DRY. ON SUNDAY...WEAK
COLD AIR ADVECTION BEHIND THE TROF PASSAGE WILL PRODUCE LOW
TEMPERATURES IN THE IN 20S ON SATURDAY NIGHT WITH HIGHS IN THE MID
30S ACROSS THE NORTHERN THIRD OF THE FORECAST AREA WITH HIGHS IN THE
40S OVER THE SOUTH.
MONDAY THROUGH WEDNESDAY...LATEST MEDIUM RANGE MODEL SOLUTIONS
CONTINUE TO DIVERGE BUT THERE IS OVERALL AGREEMENT IN DEVELOPING A
DEEP TROF ACROSS THE WESTERN UNITED STATES BY MID WEEK. THE ENERGETIC
SYSTEM CURRENTLY DIVING SOUTH ALONG THE WEST COAST WILL BEGIN A
PERIOD OF ACTIVE WEATHER FOR THE MIDWEST. THE 12Z GFS KEEPS THE
FORECAST AREA MAINLY DRY THROUGH TUESDAY. HOWEVER...THE 12Z ECMWF IS
FASTER AND BRINGS PRECIPITATION INTO THE REGION ON MONDAY. IN EITHER
CASE MOISTURE ADVECTION FROM THE GULF OF MEXICO AHEAD OF THE SURFACE
LOW WILL BREAK OUT PRECIPITATION EITHER MONDAY OR TUESDAY. THE
PRECIPITATION COULD FALL AS A MIXTURE OF RAIN AND SNOW.
THURSDAY AND FRIDAY...CONFIDENCE IS LOW AS MODEL SOLUTIONS SHOW
MAJOR DISCREPANCIES. THE 12Z RUN OF THE ECMWF PROGS A SURFACE
LOW TO DEVELOP OVER THE CENTRAL ROCKIES AND TRACK NORTHWEST OF IOWA
ON THURSDAY. IF THIS TRACK IS CORRECT WARM AIR ADVECTION AHEAD OF
THIS LOW WOULD PRODUCE A RAIN OR RAIN/SNOW MIX TURNING TO ALL RAIN
WITH A SNOW STORM OCCURRING OVER WESTERN IOWA AND THE NORTHERN
PLAINS. ON THE OTHER HAND THE 12Z RUN OF THE GFS TRACKS THE SURFACE
LOW FURTHER SOUTHEAST AND PROGS IT TO MOVE ACROSS MISSOURI INTO
NORTHERN ILLINOIS/INDIANA BY FRIDAY. IF THE GFS SOLUTION IS CORRECT
THERMAL PROFILES WOULD SUPPORT AN ALL SNOW EVENT LATE NEXT WEEK.
HOWEVER I MUST STRONGLY REITERATE FORECAST CONFIDENCE IS LOW.&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z FRIDAY AFTERNOON)
ISSUED AT 1136 AM CST THU NOV 28 2013
A COOL FRONT HAS SHIFTED EASTWARD INTO ILLINOIS THIS MORNING WITH
WINDS BECOMING WEST TO NORTHWEST BEHIND THE FRONT. EXPECT TAFS TO
REMAIN VFR THROUGH THE PERIOD HOWEVER MONITORING STRATUS ACROSS
THE DAKOTAS WHICH MAY MOVE INTO THE REGION AFTER 00 UTC ON FRIDAY.
IN THE MEAN TIME A CEILING OF AROUND 4KFT WILL ROTATE THROUGH KDBQ
AND KCID THIS AFTERNOON. IF THE STRATUS REMAINS IN PLACE A BKN
CEILING OF AROUND 2500 WILL MOVE INTO ALL TAF SITES. OVERNIGHT.
CONFIDENCE IS LOW THAT THIS WILL OCCUR.
&&
.DVN WATCHES/WARNINGS/ADVISORIES...
IA...NONE.
IL...NONE.
MO...NONE.
&&
$$
SYNOPSIS...COUSINS
SHORT TERM...COUSINS
LONG TERM...KUHL
AVIATION...COUSINS
AREA FORECAST DISCUSSION
NWS GOODLAND KS
1021 AM MST THU NOV 28 2013
.SHORT TERM...(TODAY THROUGH SATURDAY NIGHT)
ISSUED AT 358 AM MST THU NOV 28 2013
FORECAST PROBLEM WILL BE TEMPERATURES. SATELLITE SHOWING AN
AMPLIFIED PATTERN FROM THE PACIFIC INTO EASTERN NORTH AMERICA.
SOUTHERN PORTION OF THE TROUGH ALONG THE WEST COAST HAS SPLIT AND
CUT OFF FROM THE NORTHERN PORTION. THIS IS LEAVING A STRONG RIDGE
OVER THE WESTERN PORTION OF THE COUNTRY WITH NORTHWEST FLOW ALOFT
OVER THE AREA. DRY AIR MASS AT ALL LEVELS IS IN PLACE ACROSS THE
REGION.
MODELS DID FINE AT UPPER LEVELS. AT MID LEVELS...THE GFS WAS DOING
THE BEST WITH THE UKMET NOT TOO FAR BEHIND IT. THE NAM WAS DOING A
LITTLE BETTER THAN THE ECMWF ON THE SURFACE WIND AND PRESSURE
FIELD. NAM AND ECMWF WERE DOING A LITTLE BETTER THAN THE GFS AND
CANADIAN ON THE LOW LEVEL THERMAL FIELD.
TODAY/TONIGHT...INTERESTING AND TRICKY TEMPERATURE FORECAST. SHALLOW
COLD FRONT WAS BEGINNING TO PUSH THROUGH THE AREA AND SHOULD BE
THROUGH MOST OF THE AREA BY 12Z TODAY. COLD AIR ADVECTION WILL
CONTINUE THROUGH THE DAY AS SURFACE BECOME EASTERLY. SOME THIN HIGH
LEVEL CLOUD COVER MAY COME IN DURING THE DAY AND CONTINUE INTO
TONIGHT BUT DO NOT EXPECT IT TO BE HAMPER WARMING. WHAT MAY IMPACT
HIGH TEMPERATURES TODAY IS LARGE AREA OF STRATUS MOVING SOUTH
ACROSS NEBRASKA AT THIS TIME.
THE RAP AND NAM TENDED TO CATCH THIS BUT WERE EITHER NOT FAR ENOUGH
SOUTH OR WEST WITH THIS AREA. TAKING THOSE MODELS AT FACE VALUE
WOULD SAY THAT STRATUS AND MAYBE SOME FOG WILL MOVE INTO THE
NORTHEAST PORTION OF THE AREA THIS MORNING. THE RAP IS THE MOST
AGGRESSIVE AND KEEPS THE COLDEST TEMPERATURES THERE. AFTER
COLLABORATION...ALL I DID WAS INCREASE CLOUD COVER A LITTLE.
HOWEVER WILL CONTINUE TO MONITOR TRENDS FOR AS LONG AS POSSIBLE AND
MAKE ANY NEEDED ADJUSTMENTS. TENDED TO COOLER IN THE NORTHEAST AND
WARMER IN THE WEST AND SOUTHWEST.
FOR TONIGHT MORE THAN MODEL IS NOW CONSISTENT IN BRINGING STRATUS IN
RETURN FLOW BY LATER THIS EVENING INTO THE OVERNIGHT HOURS. THE NAM
IS THE MOST AGGRESSIVE BUT THE ECMWF...GFS AND SREF ARE NOT FAR
BEHIND. WITH THIS NEW DATA AND COLLABORATION...KEPT THE FREEZING
FOG AND INCREASED THE SKY COVER AFTER 06Z. DEPENDING ON HOW FAST THE
STRATUS COMES IN...EASTERN LOCATIONS COULD DROP QUICKLY.
FRIDAY/FRIDAY NIGHT...STRATUS LOOKS TO HANG ON THROUGH THE MORNING
WHICH COULD IMPACT TEMPERATURES...ESPECIALLY IF IT HANGS ON LONGER.
MODELS STILL WAFFLING BACK AND FORTH AS TO HOW FAR BACK EAST TO TAKE
THE COLD AIR/COLD FRONT. EARLIER OUTPUT TENDED TO KEEP THE COLD AIR
FARTHER WEST WHILE THE NEWER OUTPUT IS NOW FURTHER EAST. ONE THING
FOR SURE...WILL DEFINITELY HAVE QUITE A GRADIENT IN TEMPERATURES
WITH A HIGH DEGREE OF UNCERTAINTY/POTENTIAL TO BE VERY WRONG.
SATURDAY/SATURDAY NIGHT...MODELS THEN START HAVING PROBLEMS IN
RESOLVING THE MID AND UPPER LEVEL FLOW WITH LITTLE AGREEMENT SHOWN BY
THE OUTPUT. WEST NORTHWEST TO NORTHWEST FLOW ALOFT WITH EMBEDDED
SHORTWAVES COME THROUGH DURING THIS TIME. THE STRONGEST ONE MOVES
ACROSS THE NORTH CENTRAL PORTION OF THE COUNTRY. THIS PUSHES
ANOTHER COLD FRONT THROUGH FROM LATE IN THE MORNING INTO THE EARLY
AFTERNOON. THE BRUNT OF THE COOLING LOOKS TO OCCUR OVER THE EASTERN
THIRD TO HALF. SO ONCE AGAIN THERE COULD BE A BIG GRADIENT IN
TEMPERATURES ACROSS THE AREA. CURRENT GRIDS HAD THIS LAYOUT
CAPTURED WELL AND ONLY MADE SLIGHT ADJUSTMENTS. BUT THERE IS
POTENTIAL THAT THESE TEMPERATURES WILL NEED TO BE ADJUSTED IF THE
SPEED AND POSITION OF THIS FRONT CHANGES.
THANKS TO ALL FOR THE COLLABORATION.
.LONG TERM...(SUNDAY THROUGH WEDNESDAY)
ISSUED AT 358 AM MST THU NOV 28 2013
H5 ZONAL FLOW AND H3 CONFLUENCE WILL BE IN PLACE THROUGH THE EARLY
PART OF THE WEEK...WHICH WILL SUPPORT LARGE SCALE STABLE/DRY
CONDITIONS OVER MUCH OF THE PLAINS. SURFACE TO H85 W-SW FLOW
ASSOCIATED WITH LEE TROUGH DEVELOPMENT ALONG THE KS/CO BORDER WILL
SUPPORT WAA AND MILD TEMPERATURES ACROSS THE REGION. A WEAK COLD
FRONT OVER THE NORTHERN PLAINS WILL LIFT NORTH AND EAST SUNDAY WITH
HIGHS WARMING TO LOW TO MID 50S. CONTINUED MODERATION OF AIR MASS ON
MONDAY SHOULD SUPPORT HIGHS AT LEAST IN THE MID 50S. ECMWF MOS
CONTINUES TO SHOW HIGHS IN UPPER 50S/NEAR 60F AND BASED ON WARM
EPISODES IN THE SHORT TERM THIS MIGHT BE REASONABLE.
TUESDAY-WEDNESDAY NIGHT...LESS CONFIDENCE IN THESE PERIODS REGARDING
FINER DETAILS OF TEMPS/PRECIP CHANCES...HOWEVER GUIDANCE CONTINUES
TO ADVERTISE A LARGE SCALE SHIFT IN THE PATTERN ACROSS THE WESTERN
US. A STRONG UPPER LOW ORIGINATING OVER ALASKA IS ADVERTISED TO DROP
SOUTH ALONG AMPLIFIED PACIFIC RIDGE INTO THE PACIFIC NW BY MONDAY
NIGHT PULLING WITH IT A STRONG ARCTIC AIR MASS FROM POLAR REGIONS
INTO THE NORTHERN PLAINS. GEM IS THE FASTEST ON ARCTIC FRONT MOVING
INTO OUR CWA TUESDAY EVENING...HOWEVER LAST FEW RUNS OF
ECMWF/GFS/GEFS LEAN TOWARDS A SLOWER FRONTAL TIMING (POSSIBLY AS
LATE AS WED NIGHT). THERE IS A LARGE AMOUNT OF SPREAD REGARDING THE
EVOLUTION OF THE UPPER LOW IN THE WESTERN US...WHICH WILL IMPACT
ONSET OF PRECIPITATION AND THE MAGNITUDE OF COLD AIR. YESTERDAYS 12Z
RUN OF ECMWF WAS AN EXTREME (AND CONCERNING) OUTLIER WITH H85 TEMPS
BY NEXT THU -20C OR COLDER OVER PARTS OF OUR CWA. LATEST RUN OF
ECMWF AND GFS ARE A LITTLE MORE IN LINE...HOWEVER BOTH WOULD SUPPORT
VERY COLD TEMPERATURES SETTLING IN BY AT LEAST THE LATER PART OF
NEXT WEEK. CONSIDERING THE PATTERN SHOULD SUPPORT AT LEAST BREEZY
CONDITIONS AND VERY COLD OVERNIGHT TEMPS WE MAY END UP SEEING THE
NEED FOR A WIND CHILL ADVISORY (WC VALUES LESS/EQUAL TO -15F) OR
WARNING IF THE EXTREME SPECTRUM OF GUIDANCE WERE TO VERIFY. I TEND
TO LEAN TOWARD THE MODEL MEAN AT THIS POINT FOR TUE/WED CONSIDERING
RUN-RUN DIFFERENCES WHICH SHOWS COLDER TEMPS AND BETTER PRECIP
CHANCES DELAYED TOWARDS WED/WED NIGHT AND OUTSIDE OUR CURRENT VALID
FORECAST PERIOD.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z FRIDAY AFTERNOON)
ISSUED AT 1014 AM MST THU NOV 28 2013
AT KMCK...STRATUS DECK HAS BEEN STEADILY ADVANCING TOWARDS THE
TERMINAL ALL MORNING AND A PERIOD OF LOWER CIGS IS EXPECTED
ROUGHLY BETWEEN 19Z AND 22Z THIS AFTERNOON. SATELLITE TRENDS SHOW
SOME EROSION ON THE LEADING EDGE...SO THERE IS STILL SOME
UNCERTAINTY THAT THE STRATUS CAN BE MAINTAINED WITH SURFACE
HEATING. TONIGHT...LOW CIGS WITH THE STRATUS WILL STILL BE A
POSSIBILITY ALTHOUGH THE WINDS ARE LIGHT THEY WILL HAVE AN UPSLOPE
COMPONENT. PATCHY FREEZING FOG MAY ALSO DEVELOP IN THE OVERNIGHT
BUT CONFIDENCE IS LACKING TO MENTION ATTM.
AT KGLD...VFR EXPECTED THROUGH THE AFTERNOON AND EARLY EVENING.
HOWEVER AS THE NIGHT WEARS ON LIGHT UPSLOPE WINDS WILL CONTRIBUTE
TO THE DEVELOPMENT OF STRATUS AND POSSIBLE LOW CIGS. PATCHY FREEZING
FOG MAY ALSO DEVELOP IN THE OVERNIGHT BUT CONFIDENCE IS LACKING
TO MENTION ATTM.
&&
.GLD WATCHES/WARNINGS/ADVISORIES...
KS...NONE.
CO...NONE.
NE...NONE.
&&
$$
SHORT TERM...BULLER
LONG TERM...DJR
AVIATION...024
AREA FORECAST DISCUSSION
NWS GOODLAND KS
446 AM MST THU NOV 28 2013
.SHORT TERM...(TODAY THROUGH SATURDAY NIGHT)
ISSUED AT 358 AM MST THU NOV 28 2013
FORECAST PROBLEM WILL BE TEMPERATURES. SATELLITE SHOWING AN
AMPLIFIED PATTERN FROM THE PACIFIC INTO EASTERN NORTH AMERICA.
SOUTHERN PORTION OF THE TROUGH ALONG THE WEST COAST HAS SPLIT AND
CUT OFF FROM THE NORTHERN PORTION. THIS IS LEAVING A STRONG RIDGE
OVER THE WESTERN PORTION OF THE COUNTRY WITH NORTHWEST FLOW ALOFT
OVER THE AREA. DRY AIR MASS AT ALL LEVELS IS IN PLACE ACROSS THE
REGION.
MODELS DID FINE AT UPPER LEVELS. AT MID LEVELS...THE GFS WAS DOING
THE BEST WITH THE UKMET NOT TOO FAR BEHIND IT. THE NAM WAS DOING A
LITTLE BETTER THAN THE ECMWF ON THE SURFACE WIND AND PRESSURE
FIELD. NAM AND ECMWF WERE DOING A LITTLE BETTER THAN THE GFS AND
CANADIAN ON THE LOW LEVEL THERMAL FIELD.
TODAY/TONIGHT...INTERESTING AND TRICKY TEMPERATURE FORECAST. SHALLOW
COLD FRONT WAS BEGINNING TO PUSH THROUGH THE AREA AND SHOULD BE
THROUGH MOST OF THE AREA BY 12Z TODAY. COLD AIR ADVECTION WILL
CONTINUE THROUGH THE DAY AS SURFACE BECOME EASTERLY. SOME THIN HIGH
LEVEL CLOUD COVER MAY COME IN DURING THE DAY AND CONTINUE INTO
TONIGHT BUT DO NOT EXPECT IT TO BE HAMPER WARMING. WHAT MAY IMPACT
HIGH TEMPERATURES TODAY IS LARGE AREA OF STRATUS MOVING SOUTH
ACROSS NEBRASKA AT THIS TIME.
THE RAP AND NAM TENDED TO CATCH THIS BUT WERE EITHER NOT FAR ENOUGH
SOUTH OR WEST WITH THIS AREA. TAKING THOSE MODELS AT FACE VALUE
WOULD SAY THAT STRATUS AND MAYBE SOME FOG WILL MOVE INTO THE
NORTHEAST PORTION OF THE AREA THIS MORNING. THE RAP IS THE MOST
AGGRESSIVE AND KEEPS THE COLDEST TEMPERATURES THERE. AFTER
COLLABORATION...ALL I DID WAS INCREASE CLOUD COVER A LITTLE.
HOWEVER WILL CONTINUE TO MONITOR TRENDS FOR AS LONG AS POSSIBLE AND
MAKE ANY NEEDED ADJUSTMENTS. TENDED TO COOLER IN THE NORTHEAST AND
WARMER IN THE WEST AND SOUTHWEST.
FOR TONIGHT MORE THAN MODEL IS NOW CONSISTENT IN BRINGING STRATUS IN
RETURN FLOW BY LATER THIS EVENING INTO THE OVERNIGHT HOURS. THE NAM
IS THE MOST AGGRESSIVE BUT THE ECMWF...GFS AND SREF ARE NOT FAR
BEHIND. WITH THIS NEW DATA AND COLLABORATION...KEPT THE FREEZING
FOG AND INCREASED THE SKY COVER AFTER 06Z. DEPENDING ON HOW FAST THE
STRATUS COMES IN...EASTERN LOCATIONS COULD DROP QUICKLY.
FRIDAY/FRIDAY NIGHT...STRATUS LOOKS TO HANG ON THROUGH THE MORNING
WHICH COULD IMPACT TEMPERATURES...ESPECIALLY IF IT HANGS ON LONGER.
MODELS STILL WAFFLING BACK AND FORTH AS TO HOW FAR BACK EAST TO TAKE
THE COLD AIR/COLD FRONT. EARLIER OUTPUT TENDED TO KEEP THE COLD AIR
FARTHER WEST WHILE THE NEWER OUTPUT IS NOW FURTHER EAST. ONE THING
FOR SURE...WILL DEFINITELY HAVE QUITE A GRADIENT IN TEMPERATURES
WITH A HIGH DEGREE OF UNCERTAINTY/POTENTIAL TO BE VERY WRONG.
SATURDAY/SATURDAY NIGHT...MODELS THEN START HAVING PROBLEMS IN
RESOLVING THE MID AND UPPER LEVEL FLOW WITH LITTLE AGREEMENT SHOWN BY
THE OUTPUT. WEST NORTHWEST TO NORTHWEST FLOW ALOFT WITH EMBEDDED
SHORTWAVES COME THROUGH DURING THIS TIME. THE STRONGEST ONE MOVES
ACROSS THE NORTH CENTRAL PORTION OF THE COUNTRY. THIS PUSHES
ANOTHER COLD FRONT THROUGH FROM LATE IN THE MORNING INTO THE EARLY
AFTERNOON. THE BRUNT OF THE COOLING LOOKS TO OCCUR OVER THE EASTERN
THIRD TO HALF. SO ONCE AGAIN THERE COULD BE A BIG GRADIENT IN
TEMPERATURES ACROSS THE AREA. CURRENT GRIDS HAD THIS LAYOUT
CAPTURED WELL AND ONLY MADE SLIGHT ADJUSTMENTS. BUT THERE IS
POTENTIAL THAT THESE TEMPERATURES WILL NEED TO BE ADJUSTED IF THE
SPEED AND POSITION OF THIS FRONT CHANGES.
THANKS TO ALL FOR THE COLLABORATION.
.LONG TERM...(SUNDAY THROUGH WEDNESDAY)
ISSUED AT 358 AM MST THU NOV 28 2013
H5 ZONAL FLOW AND H3 CONFLUENCE WILL BE IN PLACE THROUGH THE EARLY
PART OF THE WEEK...WHICH WILL SUPPORT LARGE SCALE STABLE/DRY
CONDITIONS OVER MUCH OF THE PLAINS. SURFACE TO H85 W-SW FLOW
ASSOCIATED WITH LEE TROUGH DEVELOPMENT ALONG THE KS/CO BORDER WILL
SUPPORT WAA AND MILD TEMPERATURES ACROSS THE REGION. A WEAK COLD
FRONT OVER THE NORTHERN PLAINS WILL LIFT NORTH AND EAST SUNDAY WITH
HIGHS WARMING TO LOW TO MID 50S. CONTINUED MODERATION OF AIR MASS ON
MONDAY SHOULD SUPPORT HIGHS AT LEAST IN THE MID 50S. ECMWF MOS
CONTINUES TO SHOW HIGHS IN UPPER 50S/NEAR 60F AND BASED ON WARM
EPISODES IN THE SHORT TERM THIS MIGHT BE REASONABLE.
TUESDAY-WEDNESDAY NIGHT...LESS CONFIDENCE IN THESE PERIODS REGARDING
FINER DETAILS OF TEMPS/PRECIP CHANCES...HOWEVER GUIDANCE CONTINUES
TO ADVERTISE A LARGE SCALE SHIFT IN THE PATTERN ACROSS THE WESTERN
US. A STRONG UPPER LOW ORIGINATING OVER ALASKA IS ADVERTISED TO DROP
SOUTH ALONG AMPLIFIED PACIFIC RIDGE INTO THE PACIFIC NW BY MONDAY
NIGHT PULLING WITH IT A STRONG ARCTIC AIR MASS FROM POLAR REGIONS
INTO THE NORTHERN PLAINS. GEM IS THE FASTEST ON ARCTIC FRONT MOVING
INTO OUR CWA TUESDAY EVENING...HOWEVER LAST FEW RUNS OF
ECMWF/GFS/GEFS LEAN TOWARDS A SLOWER FRONTAL TIMING (POSSIBLY AS
LATE AS WED NIGHT). THERE IS A LARGE AMOUNT OF SPREAD REGARDING THE
EVOLUTION OF THE UPPER LOW IN THE WESTERN US...WHICH WILL IMPACT
ONSET OF PRECIPITATION AND THE MAGNITUDE OF COLD AIR. YESTERDAYS 12Z
RUN OF ECMWF WAS AN EXTREME (AND CONCERNING) OUTLIER WITH H85 TEMPS
BY NEXT THU -20C OR COLDER OVER PARTS OF OUR CWA. LATEST RUN OF
ECWMF AND GFS ARE A LITTLE MORE IN LINE...HOWEVER BOTH WOULD SUPPORT
VERY COLD TEMPERATURES SETTLING IN BY AT LEAST THE LATER PART OF
NEXT WEEK. CONSIDERING THE PATTERN SHOULD SUPPORT AT LEAST BREEZY
CONDITIONS AND VERY COLD OVERNIGHT TEMPS WE MAY END UP SEEING THE
NEED FOR A WIND CHILL ADVISORY (WC VALUES LESS/EQUAL TO -15F) OR
WARNING IF THE EXTREME SPECTRUM OF GUIDANCE WERE TO VERIFY. I TEND
TO LEAN TOWARD THE MODEL MEAN AT THIS POINT FOR TUE/WED CONSIDERING
RUN-RUN DIFFERENCES WHICH SHOWS COLDER TEMPS AND BETTER PRECIP
CHANCES DELAYED TOWARDS WED/WED NIGHT AND OUTSIDE OUR CURRENT VALID
FORECAST PERIOD.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z FRIDAY MORNING)
ISSUED AT 441 AM MST THU NOV 28 2013
MAIN PROBLEMS TO DEAL WITH ARE STRATUS NEAR KMCK IN THE FIRST PART
OF THE PERIOD AND STRATUS FOR BOTH SITES...ESPECIALLY AT KGLD...TOWARD
THE END OF THE PERIOD. COLD FRONT HAS MOVED THROUGH BOTH SITES. A
LARGE AREA OF STRATUS HAS BEEN MOVING SOUTH ACROSS NEBRASKA. THIS
AREA IS STILL WELL TO THE NORTHEAST OF KMCK. AT THIS TIME IT LOOKS
LIKE THE EDGE OF THIS STRATUS FIELD WILL COME CLOSE TO KMCK. SO
FROM MID MORNING UNTIL EARLY AFTERNOON PUT IN A SCATTERED LOW DECK
WITH A TEMPO GROUP COVERING THE POSSIBILITY OF A MVFR CEILING.
LATER TONIGHT AS SOUTHERLY WINDS INCREASE ON THE WEST SIDE OF THE
EXITING SURFACE HIGH...LOW LEVEL MOISTURE WILL BE DRAWN NORTHWARD.
AT THIS TIME IT LOOK LIKE KGLD HAVE MVFR CEILINGS DEVELOP AFTER
06Z. IT LOOKS LIKE ANY CEILINGS WILL STAY TO THE WEST OF KMCK AT
THIS TIME.
&&
.GLD WATCHES/WARNINGS/ADVISORIES...
KS...NONE.
CO...NONE.
NE...NONE.
&&
$$
SHORT TERM...BULLER
LONG TERM...DJR
AVIATION...BULLER
AREA FORECAST DISCUSSION
NWS GOODLAND KS
358 AM MST THU NOV 28 2013
.SHORT TERM...(TODAY THROUGH SATURDAY NIGHT)
ISSUED AT 358 AM MST THU NOV 28 2013
FORECAST PROBLEM WILL BE TEMPERATURES. SATELLITE SHOWING AN
AMPLIFIED PATTERN FROM THE PACIFIC INTO EASTERN NORTH AMERICA.
SOUTHERN PORTION OF THE TROUGH ALONG THE WEST COAST HAS SPLIT AND
CUT OFF FROM THE NORTHERN PORTION. THIS IS LEAVING A STRONG RIDGE
OVER THE WESTERN PORTION OF THE COUNTRY WITH NORTHWEST FLOW ALOFT
OVER THE AREA. DRY AIR MASS AT ALL LEVELS IS IN PLACE ACROSS THE
REGION.
MODELS DID FINE AT UPPER LEVELS. AT MID LEVELS...THE GFS WAS DOING
THE BEST WITH THE UKMET NOT TOO FAR BEHIND IT. THE NAM WAS DOING A
LITTLE BETTER THAN THE ECMWF ON THE SURFACE WIND AND PRESSURE
FIELD. NAM AND ECMWF WERE DOING A LITTLE BETTER THAN THE GFS AND
CANADIAN ON THE LOW LEVEL THERMAL FIELD.
TODAY/TONIGHT...INTERESTING AND TRICKY TEMPERATURE FORECAST. SHALLOW
COLD FRONT WAS BEGINNING TO PUSH THROUGH THE AREA AND SHOULD BE
THROUGH MOST OF THE AREA BY 12Z TODAY. COLD AIR ADVECTION WILL
CONTINUE THROUGH THE DAY AS SURFACE BECOME EASTERLY. SOME THIN HIGH
LEVEL CLOUD COVER MAY COME IN DURING THE DAY AND CONTINUE INTO
TONIGHT BUT DO NOT EXPECT IT TO BE HAMPER WARMING. WHAT MAY IMPACT
HIGH TEMPERATURES TODAY IS LARGE AREA OF STRATUS MOVING SOUTH
ACROSS NEBRASKA AT THIS TIME.
THE RAP AND NAM TENDED TO CATCH THIS BUT WERE EITHER NOT FAR ENOUGH
SOUTH OR WEST WITH THIS AREA. TAKING THOSE MODELS AT FACE VALUE
WOULD SAY THAT STRATUS AND MAYBE SOME FOG WILL MOVE INTO THE
NORTHEAST PORTION OF THE AREA THIS MORNING. THE RAP IS THE MOST
AGGRESSIVE AND KEEPS THE COLDEST TEMPERATURES THERE. AFTER
COLLABORATION...ALL I DID WAS INCREASE CLOUD COVER A LITTLE.
HOWEVER WILL CONTINUE TO MONITOR TRENDS FOR AS LONG AS POSSIBLE AND
MAKE ANY NEEDED ADJUSTMENTS. TENDED TO COOLER IN THE NORTHEAST AND
WARMER IN THE WEST AND SOUTHWEST.
FOR TONIGHT MORE THAN MODEL IS NOW CONSISTENT IN BRINGING STRATUS IN
RETURN FLOW BY LATER THIS EVENING INTO THE OVERNIGHT HOURS. THE NAM
IS THE MOST AGGRESSIVE BUT THE ECMWF...GFS AND SREF ARE NOT FAR
BEHIND. WITH THIS NEW DATA AND COLLABORATION...KEPT THE FREEZING
FOG AND INCREASED THE SKY COVER AFTER 06Z. DEPENDING ON HOW FAST THE
STRATUS COMES IN...EASTERN LOCATIONS COULD DROP QUICKLY.
FRIDAY/FRIDAY NIGHT...STRATUS LOOKS TO HANG ON THROUGH THE MORNING
WHICH COULD IMPACT TEMPERATURES...ESPECIALLY IF IT HANGS ON LONGER.
MODELS STILL WAFFLING BACK AND FORTH AS TO HOW FAR BACK EAST TO TAKE
THE COLD AIR/COLD FRONT. EARLIER OUTPUT TENDED TO KEEP THE COLD AIR
FARTHER WEST WHILE THE NEWER OUTPUT IS NOW FURTHER EAST. ONE THING
FOR SURE...WILL DEFINITELY HAVE QUITE A GRADIENT IN TEMPERATURES
WITH A HIGH DEGREE OF UNCERTAINTY/POTENTIAL TO BE VERY WRONG.
SATURDAY/SATURDAY NIGHT...MODELS THEN START HAVING PROBLEMS IN
RESOLVING THE MID AND UPPER LEVEL FLOW WITH LITTLE AGREEMENT SHOWN BY
THE OUTPUT. WEST NORTHWEST TO NORTHWEST FLOW ALOFT WITH EMBEDDED
SHORTWAVES COME THROUGH DURING THIS TIME. THE STRONGEST ONE MOVES
ACROSS THE NORTH CENTRAL PORTION OF THE COUNTRY. THIS PUSHES
ANOTHER COLD FRONT THROUGH FROM LATE IN THE MORNING INTO THE EARLY
AFTERNOON. THE BRUNT OF THE COOLING LOOKS TO OCCUR OVER THE EASTERN
THIRD TO HALF. SO ONCE AGAIN THERE COULD BE A BIG GRADIENT IN
TEMPERATURES ACROSS THE AREA. CURRENT GRIDS HAD THIS LAYOUT
CAPTURED WELL AND ONLY MADE SLIGHT ADJUSTMENTS. BUT THERE IS
POTENTIAL THAT THESE TEMPERATURES WILL NEED TO BE ADJUSTED IF THE
SPEED AND POSITION OF THIS FRONT CHANGES.
THANKS TO ALL FOR THE COLLABORATION.
.LONG TERM...(SUNDAY THROUGH WEDNESDAY)
ISSUED AT 358 AM MST THU NOV 28 2013
H5 ZONAL FLOW AND H3 CONFLUENCE WILL BE IN PLACE THROUGH THE EARLY
PART OF THE WEEK...WHICH WILL SUPPORT LARGE SCALE STABLE/DRY
CONDITIONS OVER MUCH OF THE PLAINS. SURFACE TO H85 W-SW FLOW
ASSOCIATED WITH LEE TROUGH DEVELOPMENT ALONG THE KS/CO BORDER WILL
SUPPORT WAA AND MILD TEMPERATURES ACROSS THE REGION. A WEAK COLD
FRONT OVER THE NORTHERN PLAINS WILL LIFT NORTH AND EAST SUNDAY WITH
HIGHS WARMING TO LOW TO MID 50S. CONTINUED MODERATION OF AIR MASS ON
MONDAY SHOULD SUPPORT HIGHS AT LEAST IN THE MID 50S. ECMWF MOS
CONTINUES TO SHOW HIGHS IN UPPER 50S/NEAR 60F AND BASED ON WARM
EPISODES IN THE SHORT TERM THIS MIGHT BE REASONABLE.
TUESDAY-WEDNESDAY NIGHT...LESS CONFIDENCE IN THESE PERIODS REGARDING
FINER DETAILS OF TEMPS/PRECIP CHANCES...HOWEVER GUIDANCE CONTINUES
TO ADVERTISE A LARGE SCALE SHIFT IN THE PATTERN ACROSS THE WESTERN
US. A STRONG UPPER LOW ORIGINATING OVER ALASKA IS ADVERTISED TO DROP
SOUTH ALONG AMPLIFIED PACIFIC RIDGE INTO THE PACIFIC NW BY MONDAY
NIGHT PULLING WITH IT A STRONG ARCTIC AIR MASS FROM POLAR REGIONS
INTO THE NORTHERN PLAINS. GEM IS THE FASTEST ON ARCTIC FRONT MOVING
INTO OUR CWA TUESDAY EVENING...HOWEVER LAST FEW RUNS OF
ECMWF/GFS/GEFS LEAN TOWARDS A SLOWER FRONTAL TIMING (POSSIBLY AS
LATE AS WED NIGHT). THERE IS A LARGE AMOUNT OF SPREAD REGARDING THE
EVOLUTION OF THE UPPER LOW IN THE WESTERN US...WHICH WILL IMPACT
ONSET OF PRECIPITATION AND THE MAGNITUDE OF COLD AIR. YESTERDAYS 12Z
RUN OF ECMWF WAS AN EXTREME (AND CONCERNING) OUTLIER WITH H85 TEMPS
BY NEXT THU -20C OR COLDER OVER PARTS OF OUR CWA. LATEST RUN OF
ECWMF AND GFS ARE A LITTLE MORE IN LINE...HOWEVER BOTH WOULD SUPPORT
VERY COLD TEMPERATURES SETTLING IN BY AT LEAST THE LATER PART OF
NEXT WEEK. CONSIDERING THE PATTERN SHOULD SUPPORT AT LEAST BREEZY
CONDITIONS AND VERY COLD OVERNIGHT TEMPS WE MAY END UP SEEING THE
NEED FOR A WIND CHILL ADVISORY (WC VALUES LESS/EQUAL TO -15F) OR
WARNING IF THE EXTREME SPECTRUM OF GUIDANCE WERE TO VERIFY. I TEND
TO LEAN TOWARD THE MODEL MEAN AT THIS POINT FOR TUE/WED CONSIDERING
RUN-RUN DIFFERENCES WHICH SHOWS COLDER TEMPS AND BETTER PRECIP
CHANCES DELAYED TOWARDS WED/WED NIGHT AND OUTSIDE OUR CURRENT VALID
FORECAST PERIOD.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z THURSDAY NIGHT)
ISSUED AT 1029 PM MST WED NOV 27 2013
VFR CONDITIONS WILL PREVAIL ACROSS THE CENTRAL HIGH PLAINS REGION
AND THE MCK AND GLD TAF SITES THROUGH THE TAF PERIOD. LIGHT
NORTHWEST TO WEST WINDS WILL TURN NORTHEASTERLY BY 19Z THURSDAY AS
THE SURFACE HIGH PRESSURE AREA OVER THE NORTHERN PLAINS MOVES INTO
THE CENTRAL PLAINS STATES. WINDS WILL REMAIN LIGHT AND TURN
TO THE SOUTH AS THE HIGH MOVES OFF TO THE EAST AND A LEE TROUGH
DEEPENS ALONG THE FRONT RANGE AFTER 00Z FRIDAY.
&&
.GLD WATCHES/WARNINGS/ADVISORIES...
KS...NONE.
CO...NONE.
NE...NONE.
&&
$$
SHORT TERM...BULLER
LONG TERM...DJR
AVIATION...LOCKHART
AREA FORECAST DISCUSSION
NWS GRAND RAPIDS MI
1248 PM EST THU NOV 28 2013
LATEST UPDATE...
AVIATION
.SYNOPSIS...
ISSUED AT 343 AM EST THU NOV 28 2013
A CLIPPER SYSTEM WILL BRING LAKE ENHANCED SNOWFALL TO THE REGION
TODAY. TWO TO FIVE INCHES CAN BE EXPECTED BY THIS EVENING NORTH OF
I-96...WHILE AREAS SOUTH OF I-96 WILL ONLY GET TWO INCHES OR LESS.
THE SNOW IS EXPECTED TO GRADUALLY TAPER OFF TONIGHT. AFTER A QUIET
FRIDAY AND FRIDAY NIGHT...ANOTHER COLD FRONT COMES IN FOR
SATURDAY. THIS SYSTEM LOOKS TO BE WEAKER AND SHOULD ONLY GIVE THE
REGION A DUSTING OF SNOW.
THE WEEKEND AND INTO EARLY NEXT WEEK LOOKS QUIET...WITH THE NEXT
CHANCE OF PRECIPITATION COMING IN ON WEDNESDAY. HIGH TEMPERATURES
SHOULD MAINLY BE IN THE 30S.
&&
.UPDATE...
ISSUED AT 1150 PM EST THU NOV 28 2013
THE ADVISORIES HAVE BEEN UPDATED..MAIN EXPECTATION IS AREA OF
LOCALIZED 3 TO 6 INCH SNOW POTENTIAL WITH NICE AREA OF SNOW
THAT HAS DEVELOPED WEST AND NORTH OF GRAND RAPIDS AND INLAND FROM
HOLLAND...MUSKEOGON...WHITEHALL. THE HRRR HAS THE BEST HANDLE ON
THIS AREA ALTHOUGH IT DEVELOPED ABOUT 2 HOURS AHEAD OF WHAT THE
HRRR WAS INDICATING EARLIER. THIS AREA WILL PERSIST THROUGH THE
EARLY AFTNERNOON BEFORE GRADUALLY PIVOTING EAST AND SOUTH AND
WEAKENING. SO GRAND RAPIDS MAY SEE ANOTHER PERIOD OF LIGHT SNOW
LATE AFTERNOON INTO EARLY THIS EVENING...OTHERWISE THE EVENT IS
ABOUT OVER.
THE ENHANCED SNOW IS ASSOCIATED WITH AN AREA OF COVERGING LAKE
MOISTURE INTO A WEAK TROUGH OF LOW PRESSURE EXTENDING ACROSS THE
STATE. LOW LEVEL CLOUD TEMPERATURES ARE GREAT TODAY FOR BOTH THE
EFFICIENT PRODUCTION OF PRECIPITATON AND HIGH SNOW TO LIQUID
RATIOS...I.E. LARGE...DRY...AND FLUFFY SNOWFLAKES. BASED ON PAST
SIMILAR SCENARIOS...WOULD NOT BE SURPRISED TO SEE VERY LOCAL
ADDITIONAL SNOWFALL OF 6+ INCHES THIS AFTERNOON...BUT THE LIGHT
NATURE OF THE SNOW WILL MITIGATE THE POTENTIAL IMPACTS.
&&
.SHORT TERM...(TODAY THROUGH SATURDAY)
ISSUED AT 343 AM EST THU NOV 28 2013
WILL KEEP THE SAME COUNTIES IN THE HEADLINE...BUT NOW THAT WE A
TRANSITIONING INTO A SYNOPTIC/LAKE EFFECT COMBO EVENT...WILL JUST
CALL IT A WINTER WEATHER ADVISORY FOR ALL COUNTIES.
SOLID SW FLOW ENHANCED EVENT EVOLVING EARLY THIS MORNING. THE N/S
ORIENTED LAKE BAND FROM OVERNIGHT WAS BEING PUSHED INLAND AS THE
FLOW WAS GOING WEST AND WILL CONTINUE TO BACK TO THE SW LATE THIS
MORNING. DEEP MOISTURE SEEN WITHIN THE DGZ ALONG WITH A STRONG
OMEGA FOR THE CLASSIC BULLS-EYE WHICH SHOULD RESULT IN LARGER FLAKES
AND FAVORABLE ACCUMULATION RATES BY LATE MORNING/EARLY AFTERNOON.
INCREASED SNOW TOTALS FOR PORTIONS OF THE NW CWA AS THIS AREA SHOULD
SEE THE BEST SYNOPTIC/LE COMBO. FEEL WE WILL SEE A FEW 5-6 INCH
REPORTS FROM THIS ONE. THE HIGHEST TOTALS SHOULD OCCUR WHERE
OROGRAPHIC LIFT ALSO PITCHES IN...OVER NORTHERN NEWAYGO AND LAKE
COUNTIES.
AS THE WAVE PASSES EAST THE FLOW WILL PIVOT TO THE WNW TOWARD
NIGHTFALL...THEN CONTINUE TO PIVOT TO THE NNW BY LATE EVENING. THIS
WILL SPRAY MUCH OF THE WESTERN HALF WITH SNOWFALL THIS EVENING.
THEN INVERSION HEIGHTS CRASH TOWARD MIDNIGHT WHEN THE SNOW WILL
DIMINISH.
ANOTHER NORTHERN STREAM SYSTEM MOVES IN FOR SATURDAY. THIS APPEARS
TO BE A WEAKER SYSTEM THAT SHOULD ONLY PUT DOWN MINIMAL SNOWS...LESS
THAN AN INCH...AND MAINLY NORTH OF I-96. H8 TEMPS WARM BY THEN...SO
IT APPEARS THIS SYSTEM WILL NOT HAVE MUCH LAKE EFFECT POTENTIAL.
.LONG TERM...(SATURDAY NIGHT THROUGH WEDNESDAY)
ISSUED AT 343 AM EST THU NOV 28 2013
THE LONG TERM PERIOD WILL BE PREDOMINATELY DRY WITH TEMPERATURES
CLOSE TO NORMAL. SFC HIGH PRESSURE TO OUR NORTH OVER ONTARIO WILL
PROVIDE MICHIGAN WITH A DRY/COOL EASTERLY FLOW OF AIR AND A
PREDOMINATELY FLAT/ZONAL FLOW ALOFT WILL RESULT IN A VERY LOW
POTENTIAL FOR ANY SIGNIFICANT SYSTEMS.
THE UPPER FLOW DOES BEGIN TO AMPLIFY FOR THE MIDDLE TO LATE PART OF
NEXT WEEK WITH A LONG WAVE TROUGH DEVELOPING OVER THE WRN UNITED
STATES. SO THE PATTERN SHOULD BECOME MORE ACTIVE FOR SW MI BY NEXT
THURSDAY... BUT CURRENTLY IT LOOKS LIKE RAIN WOULD BE THE MAIN
PRECIP TYPE.
THE COLD FRONT WHICH PASSES THROUGH ON SATURDAY NIGHT BRINGS DOWN H8
AIR NEAR -10C. THIS SHOULD BE COLD ENOUGH TO GENERATE SOME LAKE
EFFECT CLOUDINESS AND LIGHT SNOW SHOWERS OR FLURRIES. INITIALLY ON
SUNDAY THE FLOW IS NORTHERLY WHICH SUPPORTS SOME LIGHT SNOW ACROSS
PORTIONS OF MASON AND OCEANA COUNTIES. THEN FOR SUNDAY NIGHT THROUGH
TUESDAY THE LOW LEVEL FLOW IS MORE EASTERLY WHICH MEANS MOST OF THE
AREA WILL BE DRY ALTHOUGH SOME FLURRIES FROM LAKE HURON MAY MAKE IT
INLAND TOWARD THE CLARE AREA.
THE DRY LOW LEVEL EAST FLOW AND SURFACE RIDGING MAY DELAY/FEND OFF
INCOMING WAA PRECIP NEXT WEDNESDAY BUT MAY ALSO RESULT IN A WINTRY
MIX AT THE PRECIP ONSET WED NIGHT DUE TO EVAPORATIVE COOLING/WET
BULB EFFECTS.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z FRIDAY AFTERNOON)
ISSUED AT 1239 PM EST THU NOV 28 2013
LIGHT SNOW WILL DIMINISH THIS EVENING. CIGS SHOULD REMAIN MOSTLY
VFR EXCEPT AT KMKG THIS AFTERNOON.
&&
.MARINE...
ISSUED AT 343 AM EST THU NOV 28 2013
EXTENDED THE SCA THROUGH TODAY AS THE SW FLOW REMAIN BRISK. AFTER A
CALMER PERIOD FOR TONIGHT AND FRIDAY...WE MAY NEED ANOTHER SCA BY
FRIDAY NIGHT AS SSW WINDS INCREASE.
&&
.HYDROLOGY...
ISSUED AT 343 AM EST THU NOV 28 2013
PCPN WILL BE ALL SNOW THROUGH THE SHORT TERM WITH MINIMAL MELTING...
SO NO HYDRO IMPACTS ARE EXPECTED.
&&
.GRR WATCHES/WARNINGS/ADVISORIES...
MI...WINTER WEATHER ADVISORY UNTIL 7 PM EST THIS EVENING FOR
MIZ037>040-043>046-050-051-056-057-064.
FLOOD WATCH THROUGH SATURDAY EVENING FOR MIZ045.
LM...NONE.
&&
$$
UPDATE...COBB
SYNOPSIS...JK
SHORT TERM...JK
LONG TERM...MEADE
AVIATION...93
HYDROLOGY...JK
MARINE...JK
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
1238 PM EST THU NOV 28 2013
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 520 AM EST THU NOV 28 2013
LARGE SCALE FIRST...THEN LETS TALK ABOUT MESOSCALE AND LK EFFECT
ISSUES THAT ARE PLENTY. SHORTWAVE AND LOW PRESSURE TROUGH IN COOL NW
FLOW CLOSING IN ON WESTERN UPR MICHIGAN. BATCH OF LGT SNOW EXTENDS
FROM FAR WEST CWA TO THE NORTHWEST ALONG MN/ONTARIO BORDER. SO
WIDESPREAD LGT SNOW WILL IMPACT THOSE TRAVELING THIS THANKSGIVING
MORNING...ESPECIALLY OVER WESTERN CWA AND TOWARD WISCONSIN BORDER
WHERE BETTER FORCING WITH THE SHORTWAVE RESIDES. OMEGA IN THE H7-H6
LAYER EXITS AFT 15Z...LEAVING MOSTLY NEGATIVE LARGE SCALE FORCING
THROUGH TONIGHT.
NOW ONTO THE MESOSCALE AND LAKE EFFECT ISSUES. IT IS NEVER A GOOD
THING WHEN A LARGER SCALE TROUGH MERGES INTO AN UNSTABLE AND LIGHT
WIND LAKE EFFECT ENVIRONMENT. CRAZY THINGS CAN HAPPEN. TODAY MAY END
UP BEING ONE OF THESE DAYS. ONLY TIME WILL TELL. LK EFFECT IS ALREADY
ONGOING. FIRST FOR LK SUPERIOR...STRONG MESOLOW CIRCULATION IS TAKING
OFF JUST OFFSHORE OF MUNSING AND MAY ACTUALLY BE CLIPPING GRAND
ISLAND. THIS IS LIKELY THE BEGINNING OF EVENTUAL HEAVY SNOW BAND TO
IMPACT FAR NORTHERN KEWEENAW PENINSULA...VCNTY OF DELAWARE AND COPPER
HARBOR...THOUGH MIDDAY. WINDS OVER LK SUPERIOR ARE MAINLY NE AT THIS
TIME...BUT TOWARD THE SOUTH SHORE ARE BECOMING VARIABLE OR EVEN SOUTH
THANKS TO APPROACHING LOW PRESSURE TROUGH AND LAND BREEZES /ACTUALLY
SAW TEMPS DIP BLO ZERO OVR PARTS OF INTERIOR EASTERN UPR MICHIGAN
THIS MORNING SHOWING THE CHILL OF THE AIRMASS/. AS THE MORNING WEARS
ON...INCREASING SOUTH WINDS WILL CONVERGE WITH ENE WINDS OVR LK
SUPERIOR RESULTING IN DOMINANT BAND OF SNOW OVR TIP OF KEWEENAW.
ALREADY SEEING ECHOES ON MQT RADAR NEAR COPPER HARBOR BUT NOTHING YET
PER THE KEWEENAW CO SHERIFF IN EAGLE RIVER. 00Z NAM SEEMED TOO QUICK
IN SWINGING DOMINANT BAND BACK TO SOUTH THIS AFTN. 06Z NAM ADJUSTED
AND NOW LOOKS LIKE PREFERRED 00Z GEM-REGIONAL AND LOCAL WRF-ARW AND
RUC13. UPSHOT IS HEAVIER SNOW HANGS OUT ON TIP OF KEWEENAW THROUGH
MIDDAY THEN SINKS SOUTH WITH MORE BRIEF HEAVIER SNOW SOUTH OF CALUMET
BY MID-LATE AFTN. OVERALL THE GOING LK EFFECT SNOW ADVY LOOKS
GOOD...THOUGH ISOLD AMOUNTS UP TO 10 INCHES NOT OUT QUESTION IF BAND
STAYS IN SAME LOCATION.
NOT ALL ABOUT LK SUPERIOR THOUGH AS LK MICHIGAN COULD BE INTERESTING
AS WELL. SOUTH WINDS FORMING ON LK MICHIGAN ARE LEADING TO CONCERNS
THAT LK EFFECT...POSSIBLY HEAVY...COULD IMPACT PARTS OF DELTA AND
SOUTHERN SCHOOLCRAFT INTO THIS AFTN. GRB/APX RADAR ALREADY SHOWING
SIGNS OF LK EFFECT MESO FEATURES ALONG DOOR PENINSULA AND ALONG NW
SHORE OF NORTHERN LOWER MICHIGAN. RUC13 SFC CONVERGENCE FIELD DOING
VERY NICE JOB OF PEGGING THESE AREAS AND IT SHOWS THEM MERGING OVER
FAR NORTHERN LK MICHIGAN AFT 15Z AND AFFECTING MAINLY GARDEN
PENINSULA ACROSS SOUTHERN SCHOOLCRAFT ZONE THIS AFTN. WAS VERY CLOSE
TO GO WITH ADVY...BUT CONFIDENCE WAS NOT THERE AS THESE IS UNCERTAINTY
IN HOW FAR NORTH THESE CIRCULATIONS WILL GET. RUC FCST IS VERIFYING
WELL THOUGH AND DOES GET A LOT OF MERIT. SO...WILL PASS THIS ON TO
DAYSHIFT AND LET THEM SEE HOW THINGS LOOK AFT DAYBREAK. PUT OUT A
STRONGLY WORDED SPS AND MENTIONED THAT EITHER ADVY/WARNING COULD BE
NEEDED LATER TODAY. ANYTHING IS POSSIBLE IN THIS KIND OF SETUP.
TONIGHT WILL BASICALLY BE AN EXTENSION OF HOW LK EFFECT DEVELOPS
TODAY...SO IT IS STILL KIND OF UNCERTAIN. LEANED ON NCEP HIGH RES
WRF-ARW AND NMM RUNS AS WELL AS NAM WHICH COMES BACK INTO LINE WITH
GOING THINKING. GENERALLY...SFC TROUGH SHOULD MOVE TO EASTERN LK
SUPERIOR ALLOWING WINDS TO BECOME MORE NW OR WEST OVR MUCH OF UPR
MICHIGAN. FIRST IMPACT WILL BE TO SHUNT LK EFFECT OFF LK MICHIGAN
BACK TO THE SOUTH. HAVE CHANCES VERY EARLY IN THE EVENING...THEN
DROP THEM TO SLIGHTS BY LATE EVENING. FARTHER NORTH...LK EFFECT SNOW
SHOWERS WILL BE AFFECTING NORTHWEST CWA LATE AFTN/EARLY EVENING AND
SHOULD SINK TOWARD NCNTRL UPR MICHIGAN...BIG BAY/MARQUETTE THROUGH
THE EVENING AND OVERNIGHT HOURS AND EVENTUALLY MAKE IT ONSHORE TO
EAST OF MARQUETTE TOWARD MUNISING AND GRAND MARAIS LATER TONIGHT.
MODERATE ACCUMS COULD OCCUR TONIGHT FOR HIGHER TERRAIN OF
WEST...VCNTY OF PORCUPINE MTS AND SETUP SEEMS GOOD FOR CONVERGENT
BAND OF SNOW TO AFFECT GOOD PART OF BARAGA COUNTY...MAYBE EVEN RIGHT
ALONG LK SHORE AT BARAGA/L`ANSE AS WELL. FOR NOW HAVE 2-4 INCHES IN
THERE FOR THESE AREAS THIS EVENING. LOCALLY HEAVY SNOW MAY SPREAD TO
BIG BAY/MARQUETTE LATER TONIGHT AS CONVERGENCE MAXIMIZES BTWN NW WINDS
OVER LK SUPERIOR AND POSSIBLE LAND BREEZE OVER CNTRL UPR MICHIGAN.
INLAND FM ALL THE LK EFFECT AND CLOUDS...SOME CLEARING AND LIGHTER
WINDS MAY ALLOW TEMPS TO FALL INTO THE SINGLE DIGITS TOWARD WI
BORDER AND OVER INTERIOR EASTERN CWA.
.LONG TERM...(FRIDAY THROUGH WEDNESDAY)
ISSUED AT 505 AM EST THU NOV 28 2013
FRIDAY...A SPRAWLING SFC HIGH FROM NRN ONTARIO INTO THE OHIO VALLEY
WILL RESULT IN A VERY WEAK GRADIENT ACROSS THE NRN GREAT LAKES. THE
HIGH RES MODELS SUGGEST THAT THE CIRCULATION AROUND A LAKE INDUCED
LOW OR TROUGH OVER SE LAKE SUPERIOR COULD FOCUS LES BANDS ANYWHERE FROM
MARQUETTE TO MUNISING. IF THE LOW LEVEL CONVERGENCE IS STRONG ENOUGH
THERE MAY BE A PERIOD OF HEAVY SNOW. HOWEVER...CONFIDENCE IN THE
LOCATION AND DURATION OF SUCH A BAND IS LOW. SO...FCST SNOWFALL
AMOUNTS WERE LIMITED TO AROUND AN INCH. DEVELOPING SRLY FLOW IN THE
AFTERNOON WILL PUSH THE REMAINING LES OFFSHORE. ANY SNOWBANDS MOVING
INTO THE WEST SHOULD ALSO WEAKEN AND POSSIBLY LINGER ALONG THE
SHORELINE UNTIL AFTERNOON WHEN OFF SHORE WINDS STRENGTHEN. 850 MB WAA
WILL INCREASE IN THE AFTERNOON AS WEAK MID LEVEL RIDGING MOVES BACK
OVER THE AREA AND A SFC HIGH BUILDS INTO THE ERN LAKES. HIGH TEMPS
ARE EXPECTED TO REBOUND INTO THE MID AND UPPER 20S.
FRI NIGHT AND SAT...THE MODELS WERE IN GOOD AGREEMENT WITH THE NEXT
CLIPPER SHORTWAVE TROUGH SLIDING ACROSS NRN LAKE SUPERIOR LATE IN THE
DAY ON SATURDAY. LIGHT SNOW DEVELOPING OVER SCNTRL CANADA IN THE WAA
PATTERN AHEAD OF THE SHORTWAVE WILL SPREAD SNOW ACROSS NRN LAKE
SUPERIOR FRI NIGHT PERHAPS BRUSHING THE NRN AND ERN COUNTIES WITH
SOME LIGHT SNOW LATE FRI NIGHT INTO SAT. THE STRONGER FORCING AND
BETTER SNOW POTENTIAL IS EXPECTED TO REMAIN NORTH OF LAKE SUPERIOR.
HOWEVER...THERE MAY ALSO BE A PERIOD OF LAKE ENAHCNED SNOW INTO THE
ERN CWA FROM LATE FRI NIGHT INTO SAT WITH SSW LOW LEVEL FLOW OFF OF LAKE
MI VEERING TO THE SW. THE LONG FETCH WILL BE FAVORABLE BUT
INSTABILITY WILL BE LIMITED WITH RELATIVELY DRY AIR OVER THE AREA
BEFORE THE SHRTWV ARRIVES AND WAA PUSHING 850 MB TEMPS -8C TO -5C.
SAT NIGHT...SOME LIGHT LAKE EFFECT SNOW SHOWERS ARE POSSIBLE IN THE
WAKE OF THE SFC TROUGH AS WINDS VEER FROM NW TO N AND 850 MB TEMPS
DROP FROM -10C TO -12C. WITH ONLY MARGINAL INSTABILITY...ONLY CHANCE
POPS WERE INCLUDED.
SUN INTO MON...AS HIGH PRES BUILDS INTO NRN ONTARIO WINDS WILL
CONTINUE TO VEER FROM NNE TO E. 850 MB TEMPS AROUND -12C WILL
PROVIDE JUST ENOUGH INSTABILITY TO KEEP LES CHANCES GOING ACROSS
NORTH CENTRAL UPPER MICHIGAN AND THE KEWEENAW. NEAR NORMAL TEMPS ARE
EXPECTED WITH HIGHS AROUND 30 TO THE LOWER 30S AND LOWS IN THE LOWER
20S.
TUE AND WED...MODELS DIFFER WITH THE APPROACH OF THE NEXT
SHORTWAVE EMERGING FROM THE WRN CONUS TROF. THE GFS INDICATES A MORE
POSITIVE-TILT WRN CONUS TROF AND LESS AMPLIFICATION OF RIDGE
DOWNSTREAM ALLOWING FOR A QUICKER ADVANCE OF A SHORTWAVE AND ASSOCIATED
FRONTAL SYSTEM INTO THE WRN LAKES. THE ECMWF INDICATES A MORE
AMPLIFIED PATTERN ACROSS THE CONUS WITH A SLOWER ADVANCE OF THE
SHORTWAVE MOVING TOWARD THE WRN LAKES. THE FCST CONTINUED TO USE A
MDLS CONSENSUS THAT REFLECTS A SLIGHTLY LATER ARRIVAL OF PCPN
CHANCES FROM TUE NIGHT INTO WED. THE MODELS ALSO TRENDED TOWARD A
LESS AMPLIFIED SOLUTION WITH COLDER AIR ACROSS THE NRN LAKES WHICH
WOULD REDUCE THE CHANCE FOR ANY RAIN.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z FRIDAY AFTERNOON)
ISSUED AT 1237 PM EST THU NOV 28 2013
FORECAST WILL BE A CHALLENGE OVER THE NEXT 24HRS. MULTIPLE MESO-LOWS
OVER LAKE SUPERIOR THAT ARE NOT HANDLED WELL BY ANY MODELS SHOULD
MOVE ONSHORE TODAY INTO TONIGHT...MAKING ALL TAF ELEMENTS VERY
DIFFICULT TO FORECAST MORE THAN A COUPLE HOURS OUT. PUT BEST GUESS
INTO TAFS...BUT MULTIPLE AMENDMENTS MAY BE NEEDED AS VERY SMALL
SCALE FEATURES MOVE OVER TAF SITES. SEEMS CMX HAS THE BEST CHANCE OF
SEEING LOWERED CONDITIONS AS A HEAVY LAKE EFFECT SNOW BAND OVER THE
NORTHERN KEWEENAW MOVES SOUTH. IWD HAS THE NEXT BEST CHANCE OF
LOWERING CONDITIONS AS A STRONG MESO-LOW OVER WESTERN LAKE SUPERIOR
MOVES ONSHORE IN NW WI OR WRN UPPER MI. SAW HAS THE LOWEST CHANCES
OF SEEING DECREASED CONDITIONS...BUT THERE IS STILL A CHANCE THAT A
MESO-LOW OVER SOUTH CENTRAL LAKE SUPERIOR WILL MOVE ONSHORE NEAR
MARQUETTE THAT WOULD IMPACT THAT SITE AS WELL.
&&
.MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 343 PM EST WED NOV 27 2013
STRONGER N WINDS WILL CONTINUE TO SLOWLY DIMINISH THIS EVENING. A
RIDGE OF HIGH PRESSURE WILL EXTEND OVER LAKE SUPERIOR THIS
EVENING...WHILE A WEAK LOW OVER THE EASTERN DAKOTAS PUSHES ACROSS
THE UPPER GREAT LAKES LATE TONIGHT THROUGH THURSDAY. LARGER HIGH
PRESSURE EXTENDING ACROSS MUCH OF CENTRAL CANADA THROUGH THE CENTRAL
PLAINS THURSDAY AFTERNOON WILL SWING ACROSS THE UPPER GREAT LAKES
THURSDAY NIGHT...BEFORE EXITING TO THE LOWER GREAT LAKES AND NEW
ENGLAND STATES FRIDAY AFTERNOON THROUGH SATURDAY. EXPECT A LOW OVER
LAKE WINNIPEG FRIDAY NIGHT TO PUSH ACROSS SOUTHERN ONTARIO AND LAKE
SUPERIOR SATURDAY AND SATURDAY EVENING. THERE IS THE POTENTIAL FOR
30KT S GUSTS DURING THE DAY SATURDAY. FOR SUNDAY AND MONDAY...HIGH
PRESSURE SCOOTING ACROSS ONTARIO WILL PUSH A RIDGE OVER LAKE
SUPERIOR.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
LAKE EFFECT SNOW ADVISORY UNTIL 5 PM EST THIS AFTERNOON FOR
MIZ001.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...JLA
LONG TERM...JLB
AVIATION...TITUS
MARINE...KF
AREA FORECAST DISCUSSION
NWS GRAND RAPIDS MI
1154 AM EST THU NOV 28 2013
LATEST UPDATE...MORNING UPDATE
.SYNOPSIS...
ISSUED AT 343 AM EST THU NOV 28 2013
A CLIPPER SYSTEM WILL BRING LAKE ENHANCED SNOWFALL TO THE REGION
TODAY. TWO TO FIVE INCHES CAN BE EXPECTED BY THIS EVENING NORTH OF
I-96...WHILE AREAS SOUTH OF I-96 WILL ONLY GET TWO INCHES OR LESS.
THE SNOW IS EXPECTED TO GRADUALLY TAPER OFF TONIGHT. AFTER A QUIET
FRIDAY AND FRIDAY NIGHT...ANOTHER COLD FRONT COMES IN FOR
SATURDAY. THIS SYSTEM LOOKS TO BE WEAKER AND SHOULD ONLY GIVE THE
REGION A DUSTING OF SNOW.
THE WEEKEND AND INTO EARLY NEXT WEEK LOOKS QUIET...WITH THE NEXT
CHANCE OF PRECIPITATION COMING IN ON WEDNESDAY. HIGH TEMPERATURES
SHOULD MAINLY BE IN THE 30S.
&&
.UPDATE...
ISSUED AT 1150 PM EST THU NOV 28 2013
THE ADVISORIES HAVE BEEN UPDATED..MAIN EXPECTATION IS AREA OF
LOCALIZED 3 TO 6 INCH SNOW POTENTIAL WITH NICE AREA OF SNOW
THAT HAS DEVELOPED WEST AND NORTH OF GRAND RAPIDS AND INLAND FROM
HOLLAND...MUSKEOGON...WHITEHALL. THE HRRR HAS THE BEST HANDLE ON
THIS AREA ALTHOUGH IT DEVELOPED ABOUT 2 HOURS AHEAD OF WHAT THE
HRRR WAS INDICATING EARLIER. THIS AREA WILL PERSIST THROUGH THE
EARLY AFTNERNOON BEFORE GRADUALLY PIVOTING EAST AND SOUTH AND
WEAKENING. SO GRAND RAPIDS MAY SEE ANOTHER PERIOD OF LIGHT SNOW
LATE AFTERNOON INTO EARLY THIS EVENING...OTHERWISE THE EVENT IS
ABOUT OVER.
THE ENHANCED SNOW IS ASSOCIATED WITH AN AREA OF COVERGING LAKE
MOISTURE INTO A WEAK TROUGH OF LOW PRESSURE EXTENDING ACROSS THE
STATE. LOW LEVEL CLOUD TEMPERATURES ARE GREAT TODAY FOR BOTH THE
EFFICIENT PRODUCTION OF PRECIPITATON AND HIGH SNOW TO LIQUID
RATIOS...I.E. LARGE...DRY...AND FLUFFY SNOWFLAKES. BASED ON PAST
SIMILAR SCENARIOS...WOULD NOT BE SURPRISED TO SEE VERY LOCAL
ADDITIONAL SNOWFALL OF 6+ INCHES THIS AFTERNOON...BUT THE LIGHT
NATURE OF THE SNOW WILL MITIGATE THE POTENTIAL IMPACTS.
&&
.SHORT TERM...(TODAY THROUGH SATURDAY)
ISSUED AT 343 AM EST THU NOV 28 2013
WILL KEEP THE SAME COUNTIES IN THE HEADLINE...BUT NOW THAT WE A
TRANSITIONING INTO A SYNOPTIC/LAKE EFFECT COMBO EVENT...WILL JUST
CALL IT A WINTER WEATHER ADVISORY FOR ALL COUNTIES.
SOLID SW FLOW ENHANCED EVENT EVOLVING EARLY THIS MORNING. THE N/S
ORIENTED LAKE BAND FROM OVERNIGHT WAS BEING PUSHED INLAND AS THE
FLOW WAS GOING WEST AND WILL CONTINUE TO BACK TO THE SW LATE THIS
MORNING. DEEP MOISTURE SEEN WITHIN THE DGZ ALONG WITH A STRONG
OMEGA FOR THE CLASSIC BULLS-EYE WHICH SHOULD RESULT IN LARGER FLAKES
AND FAVORABLE ACCUMULATION RATES BY LATE MORNING/EARLY AFTERNOON.
INCREASED SNOW TOTALS FOR PORTIONS OF THE NW CWA AS THIS AREA SHOULD
SEE THE BEST SYNOPTIC/LE COMBO. FEEL WE WILL SEE A FEW 5-6 INCH
REPORTS FROM THIS ONE. THE HIGHEST TOTALS SHOULD OCCUR WHERE
OROGRAPHIC LIFT ALSO PITCHES IN...OVER NORTHERN NEWAYGO AND LAKE
COUNTIES.
AS THE WAVE PASSES EAST THE FLOW WILL PIVOT TO THE WNW TOWARD
NIGHTFALL...THEN CONTINUE TO PIVOT TO THE NNW BY LATE EVENING. THIS
WILL SPRAY MUCH OF THE WESTERN HALF WITH SNOWFALL THIS EVENING.
THEN INVERSION HEIGHTS CRASH TOWARD MIDNIGHT WHEN THE SNOW WILL
DIMINISH.
ANOTHER NORTHERN STREAM SYSTEM MOVES IN FOR SATURDAY. THIS APPEARS
TO BE A WEAKER SYSTEM THAT SHOULD ONLY PUT DOWN MINIMAL SNOWS...LESS
THAN AN INCH...AND MAINLY NORTH OF I-96. H8 TEMPS WARM BY THEN...SO
IT APPEARS THIS SYSTEM WILL NOT HAVE MUCH LAKE EFFECT POTENTIAL.
.LONG TERM...(SATURDAY NIGHT THROUGH WEDNESDAY)
ISSUED AT 343 AM EST THU NOV 28 2013
THE LONG TERM PERIOD WILL BE PREDOMINATELY DRY WITH TEMPERATURES
CLOSE TO NORMAL. SFC HIGH PRESSURE TO OUR NORTH OVER ONTARIO WILL
PROVIDE MICHIGAN WITH A DRY/COOL EASTERLY FLOW OF AIR AND A
PREDOMINATELY FLAT/ZONAL FLOW ALOFT WILL RESULT IN A VERY LOW
POTENTIAL FOR ANY SIGNIFICANT SYSTEMS.
THE UPPER FLOW DOES BEGIN TO AMPLIFY FOR THE MIDDLE TO LATE PART OF
NEXT WEEK WITH A LONG WAVE TROUGH DEVELOPING OVER THE WRN UNITED
STATES. SO THE PATTERN SHOULD BECOME MORE ACTIVE FOR SW MI BY NEXT
THURSDAY... BUT CURRENTLY IT LOOKS LIKE RAIN WOULD BE THE MAIN
PRECIP TYPE.
THE COLD FRONT WHICH PASSES THROUGH ON SATURDAY NIGHT BRINGS DOWN H8
AIR NEAR -10C. THIS SHOULD BE COLD ENOUGH TO GENERATE SOME LAKE
EFFECT CLOUDINESS AND LIGHT SNOW SHOWERS OR FLURRIES. INITIALLY ON
SUNDAY THE FLOW IS NORTHERLY WHICH SUPPORTS SOME LIGHT SNOW ACROSS
PORTIONS OF MASON AND OCEANA COUNTIES. THEN FOR SUNDAY NIGHT THROUGH
TUESDAY THE LOW LEVEL FLOW IS MORE EASTERLY WHICH MEANS MOST OF THE
AREA WILL BE DRY ALTHOUGH SOME FLURRIES FROM LAKE HURON MAY MAKE IT
INLAND TOWARD THE CLARE AREA.
THE DRY LOW LEVEL EAST FLOW AND SURFACE RIDGING MAY DELAY/FEND OFF
INCOMING WAA PRECIP NEXT WEDNESDAY BUT MAY ALSO RESULT IN A WINTRY
MIX AT THE PRECIP ONSET WED NIGHT DUE TO EVAPORATIVE COOLING/WET
BULB EFFECTS.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z FRIDAY MORNING)
ISSUED AT 657 AM EST THU NOV 28 2013
IFR VSBYS IN SNOW ARE LIKELY AT MKG/GRR/LAN THROUGH MID MORNING
WITH MVFR TYPE VSBYS EXPECTED THEREAFTER. CONDITIONS SHOULD
IMPROVE TO VFR TONIGHT AS THE SNOW ENDS.
BASED ON WHERE THE SRN EDGE OF THE SNOW IS SETTING UP... THERE IS
A HIGH PROBABILITY OF VFR CONDITIONS WITH NO SNOW TODAY ALONG THE
I-94 CORRIDOR REGION INCLUDING AZO/BTL/JXN.
&&
.MARINE...
ISSUED AT 343 AM EST THU NOV 28 2013
EXTENDED THE SCA THROUGH TODAY AS THE SW FLOW REMAIN BRISK. AFTER A
CALMER PERIOD FOR TONIGHT AND FRIDAY...WE MAY NEED ANOTHER SCA BY
FRIDAY NIGHT AS SSW WINDS INCREASE.
&&
.HYDROLOGY...
ISSUED AT 343 AM EST THU NOV 28 2013
PCPN WILL BE ALL SNOW THROUGH THE SHORT TERM WITH MINIMAL MELTING...
SO NO HYDRO IMPACTS ARE EXPECTED.
&&
.GRR WATCHES/WARNINGS/ADVISORIES...
MI...WINTER WEATHER ADVISORY UNTIL 7 PM EST THIS EVENING FOR
MIZ037>040-043>046-050-051-056-057-064.
FLOOD WATCH THROUGH SATURDAY EVENING FOR MIZ045.
LM...NONE.
&&
$$
UPDATE...COBB
SYNOPSIS...JK
SHORT TERM...JK
LONG TERM...MEADE
AVIATION...MEADE
HYDROLOGY...JK
MARINE...JK
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
650 AM EST THU NOV 28 2013
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 520 AM EST THU NOV 28 2013
LARGE SCALE FIRST...THEN LETS TALK ABOUT MESOSCALE AND LK EFFECT
ISSUES THAT ARE PLENTY. SHORTWAVE AND LOW PRESSURE TROUGH IN COOL NW
FLOW CLOSING IN ON WESTERN UPR MICHIGAN. BATCH OF LGT SNOW EXTENDS
FROM FAR WEST CWA TO THE NORTHWEST ALONG MN/ONTARIO BORDER. SO
WIDESPREAD LGT SNOW WILL IMPACT THOSE TRAVELING THIS THANKSGIVING
MORNING...ESPECIALLY OVER WESTERN CWA AND TOWARD WISCONSIN BORDER
WHERE BETTER FORCING WITH THE SHORTWAVE RESIDES. OMEGA IN THE H7-H6
LAYER EXITS AFT 15Z...LEAVING MOSTLY NEGATIVE LARGE SCALE FORCING
THROUGH TONIGHT.
NOW ONTO THE MESOSCALE AND LAKE EFFECT ISSUES. IT IS NEVER A GOOD
THING WHEN A LARGER SCALE TROUGH MERGES INTO AN UNSTABLE AND LIGHT
WIND LAKE EFFECT ENVIRONMENT. CRAZY THINGS CAN HAPPEN. TODAY MAY END
UP BEING ONE OF THESE DAYS. ONLY TIME WILL TELL. LK EFFECT IS ALREADY
ONGOING. FIRST FOR LK SUPERIOR...STRONG MESOLOW CIRCULATION IS TAKING
OFF JUST OFFSHORE OF MUNSING AND MAY ACTUALLY BE CLIPPING GRAND
ISLAND. THIS IS LIKELY THE BEGINNING OF EVENTUAL HEAVY SNOW BAND TO
IMPACT FAR NORTHERN KEWEENAW PENINSULA...VCNTY OF DELAWARE AND COPPER
HARBOR...THOUGH MIDDAY. WINDS OVER LK SUPERIOR ARE MAINLY NE AT THIS
TIME...BUT TOWARD THE SOUTH SHORE ARE BECOMING VARIABLE OR EVEN SOUTH
THANKS TO APPROACHING LOW PRESSURE TROUGH AND LAND BREEZES /ACTUALLY
SAW TEMPS DIP BLO ZERO OVR PARTS OF INTERIOR EASTERN UPR MICHIGAN
THIS MORNING SHOWING THE CHILL OF THE AIRMASS/. AS THE MORNING WEARS
ON...INCREASING SOUTH WINDS WILL CONVERGE WITH ENE WINDS OVR LK
SUPERIOR RESULTING IN DOMINANT BAND OF SNOW OVR TIP OF KEWEENAW.
ALREADY SEEING ECHOES ON MQT RADAR NEAR COPPER HARBOR BUT NOTHING YET
PER THE KEWEENAW CO SHERIFF IN EAGLE RIVER. 00Z NAM SEEMED TOO QUICK
IN SWINGING DOMINANT BAND BACK TO SOUTH THIS AFTN. 06Z NAM ADJUSTED
AND NOW LOOKS LIKE PREFERRED 00Z GEM-REGIONAL AND LOCAL WRF-ARW AND
RUC13. UPSHOT IS HEAVIER SNOW HANGS OUT ON TIP OF KEWEENAW THROUGH
MIDDAY THEN SINKS SOUTH WITH MORE BRIEF HEAVIER SNOW SOUTH OF CALUMET
BY MID-LATE AFTN. OVERALL THE GOING LK EFFECT SNOW ADVY LOOKS
GOOD...THOUGH ISOLD AMOUNTS UP TO 10 INCHES NOT OUT QUESTION IF BAND
STAYS IN SAME LOCATION.
NOT ALL ABOUT LK SUPERIOR THOUGH AS LK MICHIGAN COULD BE INTERESTING
AS WELL. SOUTH WINDS FORMING ON LK MICHIGAN ARE LEADING TO CONCERNS
THAT LK EFFECT...POSSIBLY HEAVY...COULD IMPACT PARTS OF DELTA AND
SOUTHERN SCHOOLCRAFT INTO THIS AFTN. GRB/APX RADAR ALREADY SHOWING
SIGNS OF LK EFFECT MESO FEATURES ALONG DOOR PENINSULA AND ALONG NW
SHORE OF NORTHERN LOWER MICHIGAN. RUC13 SFC CONVERGENCE FIELD DOING
VERY NICE JOB OF PEGGING THESE AREAS AND IT SHOWS THEM MERGING OVER
FAR NORTHERN LK MICHIGAN AFT 15Z AND AFFECTING MAINLY GARDEN
PENINSULA ACROSS SOUTHERN SCHOOLCRAFT ZONE THIS AFTN. WAS VERY CLOSE
TO GO WITH ADVY...BUT CONFIDENCE WAS NOT THERE AS THESE IS UNCERTAINTY
IN HOW FAR NORTH THESE CIRCULATIONS WILL GET. RUC FCST IS VERIFYING
WELL THOUGH AND DOES GET A LOT OF MERIT. SO...WILL PASS THIS ON TO
DAYSHIFT AND LET THEM SEE HOW THINGS LOOK AFT DAYBREAK. PUT OUT A
STRONGLY WORDED SPS AND MENTIONED THAT EITHER ADVY/WARNING COULD BE
NEEDED LATER TODAY. ANYTHING IS POSSIBLE IN THIS KIND OF SETUP.
TONIGHT WILL BASICALLY BE AN EXTENSION OF HOW LK EFFECT DEVELOPS
TODAY...SO IT IS STILL KIND OF UNCERTAIN. LEANED ON NCEP HIGH RES
WRF-ARW AND NMM RUNS AS WELL AS NAM WHICH COMES BACK INTO LINE WITH
GOING THINKING. GENERALLY...SFC TROUGH SHOULD MOVE TO EASTERN LK
SUPERIOR ALLOWING WINDS TO BECOME MORE NW OR WEST OVR MUCH OF UPR
MICHIGAN. FIRST IMPACT WILL BE TO SHUNT LK EFFECT OFF LK MICHIGAN
BACK TO THE SOUTH. HAVE CHANCES VERY EARLY IN THE EVENING...THEN
DROP THEM TO SLIGHTS BY LATE EVENING. FARTHER NORTH...LK EFFECT SNOW
SHOWERS WILL BE AFFECTING NORTHWEST CWA LATE AFTN/EARLY EVENING AND
SHOULD SINK TOWARD NCNTRL UPR MICHIGAN...BIG BAY/MARQUETTE THROUGH
THE EVENING AND OVERNIGHT HOURS AND EVENTUALLY MAKE IT ONSHORE TO
EAST OF MARQUETTE TOWARD MUNISING AND GRAND MARAIS LATER TONIGHT.
MODERATE ACCUMS COULD OCCUR TONIGHT FOR HIGHER TERRAIN OF
WEST...VCNTY OF PORCUPINE MTS AND SETUP SEEMS GOOD FOR CONVERGENT
BAND OF SNOW TO AFFECT GOOD PART OF BARAGA COUNTY...MAYBE EVEN RIGHT
ALONG LK SHORE AT BARAGA/L`ANSE AS WELL. FOR NOW HAVE 2-4 INCHES IN
THERE FOR THESE AREAS THIS EVENING. LOCALLY HEAVY SNOW MAY SPREAD TO
BIG BAY/MARQUETTE LATER TONIGHT AS CONVERGENCE MAXIMIZES BTWN NW WINDS
OVER LK SUPERIOR AND POSSIBLE LAND BREEZE OVER CNTRL UPR MICHIGAN.
INLAND FM ALL THE LK EFFECT AND CLOUDS...SOME CLEARING AND LIGHTER
WINDS MAY ALLOW TEMPS TO FALL INTO THE SINGLE DIGITS TOWARD WI
BORDER AND OVER INTERIOR EASTERN CWA.
.LONG TERM...(FRIDAY THROUGH WEDNESDAY)
ISSUED AT 505 AM EST THU NOV 28 2013
FRIDAY...A SPRAWLING SFC HIGH FROM NRN ONTARIO INTO THE OHIO VALLEY
WILL RESULT IN A VERY WEAK GRADIENT ACROSS THE NRN GREAT LAKES. THE
HIGH RES MODELS SUGGEST THAT THE CIRCULATION AROUND A LAKE INDUCED
LOW OR TROUGH OVER SE LAKE SUPERIOR COULD FOCUS LES BANDS ANYWHERE FROM
MARQUETTE TO MUNISING. IF THE LOW LEVEL CONVERGENCE IS STRONG ENOUGH
THERE MAY BE A PERIOD OF HEAVY SNOW. HOWEVER...CONFIDENCE IN THE
LOCATION AND DURATION OF SUCH A BAND IS LOW. SO...FCST SNOWFALL
AMOUNTS WERE LIMITED TO AROUND AN INCH. DEVELOPING SRLY FLOW IN THE
AFTERNOON WILL PUSH THE REMAINING LES OFFSHORE. ANY SNOWBANDS MOVING
INTO THE WEST SHOULD ALSO WEAKEN AND POSSIBLY LINGER ALONG THE
SHORELINE UNTIL AFTERNOON WHEN OFF SHORE WINDS STRENGTHEN. 850 MB WAA
WILL INCREASE IN THE AFTERNOON AS WEAK MID LEVEL RIDGING MOVES BACK
OVER THE AREA AND A SFC HIGH BUILDS INTO THE ERN LAKES. HIGH TEMPS
ARE EXPECTED TO REBOUND INTO THE MID AND UPPER 20S.
FRI NIGHT AND SAT...THE MODELS WERE IN GOOD AGREEMENT WITH THE NEXT
CLIPPER SHORTWAVE TROUGH SLIDING ACROSS NRN LAKE SUPERIOR LATE IN THE
DAY ON SATURDAY. LIGHT SNOW DEVELOPING OVER SCNTRL CANADA IN THE WAA
PATTERN AHEAD OF THE SHORTWAVE WILL SPREAD SNOW ACROSS NRN LAKE
SUPERIOR FRI NIGHT PERHAPS BRUSHING THE NRN AND ERN COUNTIES WITH
SOME LIGHT SNOW LATE FRI NIGHT INTO SAT. THE STRONGER FORCING AND
BETTER SNOW POTENTIAL IS EXPECTED TO REMAIN NORTH OF LAKE SUPERIOR.
HOWEVER...THERE MAY ALSO BE A PERIOD OF LAKE ENAHCNED SNOW INTO THE
ERN CWA FROM LATE FRI NIGHT INTO SAT WITH SSW LOW LEVEL FLOW OFF OF LAKE
MI VEERING TO THE SW. THE LONG FETCH WILL BE FAVORABLE BUT
INSTABILITY WILL BE LIMITED WITH RELATIVELY DRY AIR OVER THE AREA
BEFORE THE SHRTWV ARRIVES AND WAA PUSHING 850 MB TEMPS -8C TO -5C.
SAT NIGHT...SOME LIGHT LAKE EFFECT SNOW SHOWERS ARE POSSIBLE IN THE
WAKE OF THE SFC TROUGH AS WINDS VEER FROM NW TO N AND 850 MB TEMPS
DROP FROM -10C TO -12C. WITH ONLY MARGINAL INSTABILITY...ONLY CHANCE
POPS WERE INCLUDED.
SUN INTO MON...AS HIGH PRES BUILDS INTO NRN ONTARIO WINDS WILL
CONTINUE TO VEER FROM NNE TO E. 850 MB TEMPS AROUND -12C WILL
PROVIDE JUST ENOUGH INSTABILITY TO KEEP LES CHANCES GOING ACROSS
NORTH CENTRAL UPPER MICHIGAN AND THE KEWEENAW. NEAR NORMAL TEMPS ARE
EXPECTED WITH HIGHS AROUND 30 TO THE LOWER 30S AND LOWS IN THE LOWER
20S.
TUE AND WED...MODELS DIFFER WITH THE APPROACH OF THE NEXT
SHORTWAVE EMERGING FROM THE WRN CONUS TROF. THE GFS INDICATES A MORE
POSITIVE-TILT WRN CONUS TROF AND LESS AMPLIFICATION OF RIDGE
DOWNSTREAM ALLOWING FOR A QUICKER ADVANCE OF A SHORTWAVE AND ASSOCIATED
FRONTAL SYSTEM INTO THE WRN LAKES. THE ECMWF INDICATES A MORE
AMPLIFIED PATTERN ACROSS THE CONUS WITH A SLOWER ADVANCE OF THE
SHORTWAVE MOVING TOWARD THE WRN LAKES. THE FCST CONTINUED TO USE A
MDLS CONSENSUS THAT REFLECTS A SLIGHTLY LATER ARRIVAL OF PCPN
CHANCES FROM TUE NIGHT INTO WED. THE MODELS ALSO TRENDED TOWARD A
LESS AMPLIFIED SOLUTION WITH COLDER AIR ACROSS THE NRN LAKES WHICH
WOULD REDUCE THE CHANCE FOR ANY RAIN.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z FRIDAY MORNING)
ISSUED AT 649 AM EST THU NOV 28 2013
FCST WILL BE A CHALLENGE OVER THE NEXT 24HRS. WITH DISTURBANCE
APPROACHING FROM THE NW...WINDS HAVE SWUNG AROUND TO A LIGHT S TO
SW DIRECTION. -SN ASSOCIATED WITH APPROACHING DISTURBANCE WILL
AFFECT ALL THE TAF SITES WITH MAINLY MVFR CONDITIONS THIS MORNING.
OTHERWISE...FOCUS WILL SHIFT TO MESOLOW DEVELOPING OVER WRN LAKE
SUPERIOR THIS MORNING. AS THE LOW SHIFTS INTO WRN UPPER MI THIS
AFTN...A PERIOD OF MDT TO POTENTIALLY HVY SNOW WILL IMPACT KIWD/KCMX
AS WINDS SHIFT TO AN ONSHORE DIRECTION. FOR NOW...INCLUDED IFR
CONDITIONS AT BOTH TERMINALS FOR SEVERAL HRS IN THE AFTN TO EVENING.
OCNL LIFR CONDITIONS NOT OUT OF THE QUESTION. BEST SHOT OF THAT WILL
BE AT CMX SO INCLUDED TEMPO GROUP. KSAW SHOULD GENERALLY REMAIN VFR
INTO THE AFTN BEFORE WINDS BECOME LIGHT NRLY. MIGHT BE A PERIOD OF
HEAVIER SHSN/LOWER CONDITIONS AT KSAW THIS EVENING. &&
.MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 343 PM EST WED NOV 27 2013
STRONGER N WINDS WILL CONTINUE TO SLOWLY DIMINISH THIS EVENING. A
RIDGE OF HIGH PRESSURE WILL EXTEND OVER LAKE SUPERIOR THIS
EVENING...WHILE A WEAK LOW OVER THE EASTERN DAKOTAS PUSHES ACROSS
THE UPPER GREAT LAKES LATE TONIGHT THROUGH THURSDAY. LARGER HIGH
PRESSURE EXTENDING ACROSS MUCH OF CENTRAL CANADA THROUGH THE CENTRAL
PLAINS THURSDAY AFTERNOON WILL SWING ACROSS THE UPPER GREAT LAKES
THURSDAY NIGHT...BEFORE EXITING TO THE LOWER GREAT LAKES AND NEW
ENGLAND STATES FRIDAY AFTERNOON THROUGH SATURDAY. EXPECT A LOW OVER
LAKE WINNIPEG FRIDAY NIGHT TO PUSH ACROSS SOUTHERN ONTARIO AND LAKE
SUPERIOR SATURDAY AND SATURDAY EVENING. THERE IS THE POTENTIAL FOR
30KT S GUSTS DURING THE DAY SATURDAY. FOR SUNDAY AND MONDAY...HIGH
PRESSURE SCOOTING ACROSS ONTARIO WILL PUSH A RIDGE OVER LAKE
SUPERIOR.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
LAKE EFFECT SNOW ADVISORY UNTIL 5 PM EST THIS AFTERNOON FOR
MIZ001.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...JLA
LONG TERM...JLB
AVIATION...JLA
MARINE...KF
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
521 AM EST THU NOV 28 2013
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 520 AM EST THU NOV 28 2013
LARGE SCALE FIRST...THEN LETS TALK ABOUT MESOSCALE AND LK EFFECT
ISSUES THAT ARE PLENTY. SHORTWAVE AND LOW PRESSURE TROUGH IN COOL NW
FLOW CLOSING IN ON WESTERN UPR MICHIGAN. BATCH OF LGT SNOW EXTENDS
FROM FAR WEST CWA TO THE NORTHWEST ALONG MN/ONTARIO BORDER. SO
WIDESPREAD LGT SNOW WILL IMPACT THOSE TRAVELING THIS THANKSGIVING
MORNING...ESPECIALLY OVER WESTERN CWA AND TOWARD WISCONSIN BORDER
WHERE BETTER FORCING WITH THE SHORTWAVE RESIDES. OMEGA IN THE H7-H6
LAYER EXITS AFT 15Z...LEAVING MOSTLY NEGATIVE LARGE SCALE FORCING
THROUGH TONIGHT.
NOW ONTO THE MESOSCALE AND LAKE EFFECT ISSUES. IT IS NEVER A GOOD
THING WHEN A LARGER SCALE TROUGH MERGES INTO AN UNSTABLE AND LIGHT
WIND LAKE EFFECT ENVIRONMENT. CRAZY THINGS CAN HAPPEN. TODAY MAY END
UP BEING ONE OF THESE DAYS. ONLY TIME WILL TELL. LK EFFECT IS ALREADY
ONGOING. FIRST FOR LK SUPERIOR...STRONG MESOLOW CIRCULATION IS TAKING
OFF JUST OFFSHORE OF MUNSING AND MAY ACTUALLY BE CLIPPING GRAND
ISLAND. THIS IS LIKELY THE BEGINNING OF EVENTUAL HEAVY SNOW BAND TO
IMPACT FAR NORTHERN KEWEENAW PENINSULA...VCNTY OF DELAWARE AND COPPER
HARBOR...THOUGH MIDDAY. WINDS OVER LK SUPERIOR ARE MAINLY NE AT THIS
TIME...BUT TOWARD THE SOUTH SHORE ARE BECOMING VARIABLE OR EVEN SOUTH
THANKS TO APPROACHING LOW PRESSURE TROUGH AND LAND BREEZES /ACTUALLY
SAW TEMPS DIP BLO ZERO OVR PARTS OF INTERIOR EASTERN UPR MICHIGAN
THIS MORNING SHOWING THE CHILL OF THE AIRMASS/. AS THE MORNING WEARS
ON...INCREASING SOUTH WINDS WILL CONVERGE WITH ENE WINDS OVR LK
SUPERIOR RESULTING IN DOMINANT BAND OF SNOW OVR TIP OF KEWEENAW.
ALREADY SEEING ECHOES ON MQT RADAR NEAR COPPER HARBOR BUT NOTHING YET
PER THE KEWEENAW CO SHERIFF IN EAGLE RIVER. 00Z NAM SEEMED TOO QUICK
IN SWINGING DOMINANT BAND BACK TO SOUTH THIS AFTN. 06Z NAM ADJUSTED
AND NOW LOOKS LIKE PREFERRED 00Z GEM-REGIONAL AND LOCAL WRF-ARW AND
RUC13. UPSHOT IS HEAVIER SNOW HANGS OUT ON TIP OF KEWEENAW THROUGH
MIDDAY THEN SINKS SOUTH WITH MORE BRIEF HEAVIER SNOW SOUTH OF CALUMET
BY MID-LATE AFTN. OVERALL THE GOING LK EFFECT SNOW ADVY LOOKS
GOOD...THOUGH ISOLD AMOUNTS UP TO 10 INCHES NOT OUT QUESTION IF BAND
STAYS IN SAME LOCATION.
NOT ALL ABOUT LK SUPERIOR THOUGH AS LK MICHIGAN COULD BE INTERESTING
AS WELL. SOUTH WINDS FORMING ON LK MICHIGAN ARE LEADING TO CONCERNS
THAT LK EFFECT...POSSIBLY HEAVY...COULD IMPACT PARTS OF DELTA AND
SOUTHERN SCHOOLCRAFT INTO THIS AFTN. GRB/APX RADAR ALREADY SHOWING
SIGNS OF LK EFFECT MESO FEATURES ALONG DOOR PENINSULA AND ALONG NW
SHORE OF NORTHERN LOWER MICHIGAN. RUC13 SFC CONVERGENCE FIELD DOING
VERY NICE JOB OF PEGGING THESE AREAS AND IT SHOWS THEM MERGING OVER
FAR NORTHERN LK MICHIGAN AFT 15Z AND AFFECTING MAINLY GARDEN
PENINSULA ACROSS SOUTHERN SCHOOLCRAFT ZONE THIS AFTN. WAS VERY CLOSE
TO GO WITH ADVY...BUT CONFIDENCE WAS NOT THERE AS THESE IS UNCERTAINTY
IN HOW FAR NORTH THESE CIRCULATIONS WILL GET. RUC FCST IS VERIFYING
WELL THOUGH AND DOES GET A LOT OF MERIT. SO...WILL PASS THIS ON TO
DAYSHIFT AND LET THEM SEE HOW THINGS LOOK AFT DAYBREAK. PUT OUT A
STRONGLY WORDED SPS AND MENTIONED THAT EITHER ADVY/WARNING COULD BE
NEEDED LATER TODAY. ANYTHING IS POSSIBLE IN THIS KIND OF SETUP.
TONIGHT WILL BASICALLY BE AN EXTENSION OF HOW LK EFFECT DEVELOPS
TODAY...SO IT IS STILL KIND OF UNCERTAIN. LEANED ON NCEP HIGH RES
WRF-ARW AND NMM RUNS AS WELL AS NAM WHICH COMES BACK INTO LINE WITH
GOING THINKING. GENERALLY...SFC TROUGH SHOULD MOVE TO EASTERN LK
SUPERIOR ALLOWING WINDS TO BECOME MORE NW OR WEST OVR MUCH OF UPR
MICHIGAN. FIRST IMPACT WILL BE TO SHUNT LK EFFECT OFF LK MICHIGAN
BACK TO THE SOUTH. HAVE CHANCES VERY EARLY IN THE EVENING...THEN
DROP THEM TO SLIGHTS BY LATE EVENING. FARTHER NORTH...LK EFFECT SNOW
SHOWERS WILL BE AFFECTING NORTHWEST CWA LATE AFTN/EARLY EVENING AND
SHOULD SINK TOWARD NCNTRL UPR MICHIGAN...BIG BAY/MARQUETTE THROUGH
THE EVENING AND OVERNIGHT HOURS AND EVENTUALLY MAKE IT ONSHORE TO
EAST OF MARQUETTE TOWARD MUNISING AND GRAND MARAIS LATER TONIGHT.
MODERATE ACCUMS COULD OCCUR TONIGHT FOR HIGHER TERRAIN OF
WEST...VCNTY OF PORCUPINE MTS AND SETUP SEEMS GOOD FOR CONVERGENT
BAND OF SNOW TO AFFECT GOOD PART OF BARAGA COUNTY...MAYBE EVEN RIGHT
ALONG LK SHORE AT BARAGA/L`ANSE AS WELL. FOR NOW HAVE 2-4 INCHES IN
THERE FOR THESE AREAS THIS EVENING. LOCALLY HEAVY SNOW MAY SPREAD TO
BIG BAY/MARQUETTE LATER TONIGHT AS CONVERGENCE MAXIMIZES BTWN NW WINDS
OVER LK SUPERIOR AND POSSIBLE LAND BREEZE OVER CNTRL UPR MICHIGAN.
INLAND FM ALL THE LK EFFECT AND CLOUDS...SOME CLEARING AND LIGHTER
WINDS MAY ALLOW TEMPS TO FALL INTO THE SINGLE DIGITS TOWARD WI
BORDER AND OVER INTERIOR EASTERN CWA.
.LONG TERM...(FRIDAY THROUGH WEDNESDAY)
ISSUED AT 505 AM EST THU NOV 28 2013
FRIDAY...A SPRAWLING SFC HIGH FROM NRN ONTARIO INTO THE OHIO VALLEY
WILL RESULT IN A VERY WEAK GRADIENT ACROSS THE NRN GREAT LAKES. THE
HIGH RES MODELS SUGGEST THAT THE CIRCULATION AROUND A LAKE INDUCED
LOW OR TROUGH OVER SE LAKE SUPERIOR COULD FOCUS LES BANDS ANYWHERE FROM
MARQUETTE TO MUNISING. IF THE LOW LEVEL CONVERGENCE IS STRONG ENOUGH
THERE MAY BE A PERIOD OF HEAVY SNOW. HOWEVER...CONFIDENCE IN THE
LOCATION AND DURATION OF SUCH A BAND IS LOW. SO...FCST SNOWFALL
AMOUNTS WERE LIMITED TO AROUND AN INCH. DEVELOPING SRLY FLOW IN THE
AFTERNOON WILL PUSH THE REMAINING LES OFFSHORE. ANY SNOWBANDS MOVING
INTO THE WEST SHOULD ALSO WEAKEN AND POSSIBLY LINGER ALONG THE
SHORELINE UNTIL AFTERNOON WHEN OFF SHORE WINDS STRENGTHEN. 850 MB WAA
WILL INCREASE IN THE AFTERNOON AS WEAK MID LEVEL RIDGING MOVES BACK
OVER THE AREA AND A SFC HIGH BUILDS INTO THE ERN LAKES. HIGH TEMPS
ARE EXPECTED TO REBOUND INTO THE MID AND UPPER 20S.
FRI NIGHT AND SAT...THE MODELS WERE IN GOOD AGREEMENT WITH THE NEXT
CLIPPER SHORTWAVE TROUGH SLIDING ACROSS NRN LAKE SUPERIOR LATE IN THE
DAY ON SATURDAY. LIGHT SNOW DEVELOPING OVER SCNTRL CANADA IN THE WAA
PATTERN AHEAD OF THE SHORTWAVE WILL SPREAD SNOW ACROSS NRN LAKE
SUPERIOR FRI NIGHT PERHAPS BRUSHING THE NRN AND ERN COUNTIES WITH
SOME LIGHT SNOW LATE FRI NIGHT INTO SAT. THE STRONGER FORCING AND
BETTER SNOW POTENTIAL IS EXPECTED TO REMAIN NORTH OF LAKE SUPERIOR.
HOWEVER...THERE MAY ALSO BE A PERIOD OF LAKE ENAHCNED SNOW INTO THE
ERN CWA FROM LATE FRI NIGHT INTO SAT WITH SSW LOW LEVEL FLOW OFF OF LAKE
MI VEERING TO THE SW. THE LONG FETCH WILL BE FAVORABLE BUT
INSTABILITY WILL BE LIMITED WITH RELATIVELY DRY AIR OVER THE AREA
BEFORE THE SHRTWV ARRIVES AND WAA PUSHING 850 MB TEMPS -8C TO -5C.
SAT NIGHT...SOME LIGHT LAKE EFFECT SNOW SHOWERS ARE POSSIBLE IN THE
WAKE OF THE SFC TROUGH AS WINDS VEER FROM NW TO N AND 850 MB TEMPS
DROP FROM -10C TO -12C. WITH ONLY MARGINAL INSTABILITY...ONLY CHANCE
POPS WERE INCLUDED.
SUN INTO MON...AS HIGH PRES BUILDS INTO NRN ONTARIO WINDS WILL
CONTINUE TO VEER FROM NNE TO E. 850 MB TEMPS AROUND -12C WILL
PROVIDE JUST ENOUGH INSTABILITY TO KEEP LES CHANCES GOING ACROSS
NORTH CENTRAL UPPER MICHIGAN AND THE KEWEENAW. NEAR NORMAL TEMPS ARE
EXPECTED WITH HIGHS AROUND 30 TO THE LOWER 30S AND LOWS IN THE LOWER
20S.
TUE AND WED...MODELS DIFFER WITH THE APPROACH OF THE NEXT
SHORTWAVE EMERGING FROM THE WRN CONUS TROF. THE GFS INDICATES A MORE
POSITIVE-TILT WRN CONUS TROF AND LESS AMPLIFICATION OF RIDGE
DOWNSTREAM ALLOWING FOR A QUICKER ADVANCE OF A SHORTWAVE AND ASSOCIATED
FRONTAL SYSTEM INTO THE WRN LAKES. THE ECMWF INDICATES A MORE
AMPLIFIED PATTERN ACROSS THE CONUS WITH A SLOWER ADVANCE OF THE
SHORTWAVE MOVING TOWARD THE WRN LAKES. THE FCST CONTINUED TO USE A
MDLS CONSENSUS THAT REFLECTS A SLIGHTLY LATER ARRIVAL OF PCPN
CHANCES FROM TUE NIGHT INTO WED. THE MODELS ALSO TRENDED TOWARD A
LESS AMPLIFIED SOLUTION WITH COLDER AIR ACROSS THE NRN LAKES WHICH
WOULD REDUCE THE CHANCE FOR ANY RAIN.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z THURSDAY NIGHT)
ISSUED AT 1206 AM EST THU NOV 28 2013
FCST WILL BE A CHALLENGE OVER THE NEXT 24HRS. WITH DISTURBANCE
APPROACHING FROM THE NW...WINDS ARE IN THE PROCESS OF SWINGING
AROUND TO A LIGHT S TO SW DIRECTION. AS A RESULT...LAKE EFFECT SNOW
SHOWERS FOR THE TIME BEING HAVE ENDED AT KIWD/KCMX/KSAW...AND VFR
CONDITIONS SHOULD GENERALLY PREVAIL OVERNIGHT. HOWEVER...-SN
ASSOCIATED WITH APPROACHING DISTURBANCE MAY AFFECT KIWD OVERNIGHT
INTO THE MORNING...BRINGING MVFR CONDITIONS. OTHERWISE...FOCUS WILL
SHIFT TO MESOLOW DEVELOPING OVER WRN LAKE SUPERIOR OVERNIGHT. AS THE
LOW SHIFTS INTO WRN UPPER MI THIS AFTN...A PERIOD OF MDT TO
POTENTIALLY HVY SNOW WILL IMPACT KIWD/KCMX AS WINDS SHIFT TO AN
ONSHORE DIRECTION. FOR NOW...INCLUDED IFR CONDITIONS AT BOTH
TERMINALS FOR SEVERAL HRS IN THE AFTN TO EVENING. OCNL LIFR
CONDITIONS NOT OUT OF THE QUESTION. KSAW SHOULD GENERALLY REMAIN VFR
INTO THE AFTN BEFORE WINDS BECOME LIGHT NRLY. MIGHT BE A PERIOD OF
HEAVIER SHSN/LOWER CONDITIONS AT KSAW THIS EVENING.
&&
.MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 343 PM EST WED NOV 27 2013
STRONGER N WINDS WILL CONTINUE TO SLOWLY DIMINISH THIS EVENING. A
RIDGE OF HIGH PRESSURE WILL EXTEND OVER LAKE SUPERIOR THIS
EVENING...WHILE A WEAK LOW OVER THE EASTERN DAKOTAS PUSHES ACROSS
THE UPPER GREAT LAKES LATE TONIGHT THROUGH THURSDAY. LARGER HIGH
PRESSURE EXTENDING ACROSS MUCH OF CENTRAL CANADA THROUGH THE CENTRAL
PLAINS THURSDAY AFTERNOON WILL SWING ACROSS THE UPPER GREAT LAKES
THURSDAY NIGHT...BEFORE EXITING TO THE LOWER GREAT LAKES AND NEW
ENGLAND STATES FRIDAY AFTERNOON THROUGH SATURDAY. EXPECT A LOW OVER
LAKE WINNIPEG FRIDAY NIGHT TO PUSH ACROSS SOUTHERN ONTARIO AND LAKE
SUPERIOR SATURDAY AND SATURDAY EVENING. THERE IS THE POTENTIAL FOR
30KT S GUSTS DURING THE DAY SATURDAY. FOR SUNDAY AND MONDAY...HIGH
PRESSURE SCOOTING ACROSS ONTARIO WILL PUSH A RIDGE OVER LAKE
SUPERIOR.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
LAKE EFFECT SNOW ADVISORY UNTIL 5 PM EST THIS AFTERNOON FOR
MIZ001.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...JLA
LONG TERM...JLB
AVIATION...ROLFSON
MARINE...KF
AREA FORECAST DISCUSSION
NWS TWIN CITIES/CHANHASSEN MN
1136 AM CST THU NOV 28 2013
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 250 AM CST THU NOV 28 2013
MAIN ISSUE FOR THE SHORT TERM IS HOW LONG WILL IT TAKE FOR THE
CLOUDS TO CLEAR OUT TODAY. A 1018MB SFC LOW HAS BEEN MAKING SLOW BUT
STEADY PROGRESS ACROSS NRN IOWA OVERNIGHT AND WILL CONTINUE ON A
TRACK TOWARD SRN LAKE MICHIGAN BY THE AFTERNOON. AN INVERTED SFC
TROUGH HAS BEEN WORKING EAST ACROSS MN IN CONCERT WITH THE IOWA LOW
AND HAS HELPED MAINTAIN THE STRATUS NORTH OF THE LOW. BEHIND THIS
INVERTED TROUGH...ANOTHER CANADIAN HIGH IS BUILDING SOUTH ACROSS THE
DAKOTAS. RH TIME-HEIGHT PROFILES SHOW PLENTY OF DRYING AND
SUBSIDENCE OCCURRING AS THIS HIGH MOVES IN...WHICH IS WHY THE
QUESTION WITH THE CLOUDS IS HOW LONG DO THEY STICK AROUND. FOR
NOW...HAVE A RATHER CLOUDY FORECAST THROUGH 18Z...BUT QUICKLY START
TO IMPROVE THINGS FROM WEST TO EAST THIS AFTERNOON...IN LINE WITH
WHAT THE RAP 925-850 MB RH SHOWS.
ALTHOUGH THERE IS CURRENTLY A SEA OF LIGHT SNOW REPORTS ACROSS NRN
MN AND NODAK...THESE ARE NOT EXPECTED TO MAKE IT INTO THE MPX AREA.
THE REASON FOR THIS IS THAT SFC TEMPERATURES WHERE THE SNOW IS BEING
REPORTED RIGHT NOW ARE ALL IN THE LOW TO MID TEENS...WHICH MEANS UP
THERE...THE DENDRITIC GROWTH ZONE IS DOWN AT THE SURFACE AND EXTENDS
UP THROUGH THE CLOUD LAYER. ADD IN THE WEAK LIFT ALONG/AHEAD OF THE
INVERTED TROUGH WITH A DGZ ALL THE WAY DOWN TO THE SURFACE AND YOU
END UP WITH THE SCENARIO WHERE ALL CLOUDS HAVE SNOW. COMING DOWN TO
CENTRAL/SRN MN...SFC TEMPS DOWN HERE ARE ALL IN THE UPPER
TEENS/LOWER 20S...OUTSIDE OF THE DGZ. THE SHALLOWER DGZ THAT DOES
NOT EXTEND TO THE SFC HAS ALLOWED THE CLOUDS DOWN HERE TO REMAIN
SNOW FREE. CAA AT THE MOMENT IS NOT STRONG ENOUGH TO COOL OUR SFC
TEMPS DOWN INTO THE DGZ BEFORE WE START GETTING SOME SOLAR
HEATING...SO DO NOT ANTICIPATE THE SNOW/FLURRY REPORTS TO MAKE IT
MUCH FARTHER SOUTH THAN THEY CURRENTLY ARE.
THE COMBINATION OF WEAK CAA AND CLOUD COVER WILL AGAIN LIMIT THE
DIURNAL TEMPERATURE INCREASE AGAIN TODAY...WITH TEMPERATURES THIS
AFTERNOON ONLY EXPECTED TO INCREASE ABOUT 5 OR 10 DEGREES ABOVE
THEIR CURRENT VALUES THIS MORNING. TONIGHT...YET ANOTHER SFC RIDGE
AXIS WILL BE CENTERED ACROSS THE AREA...RESULTING IN ANOTHER NIGHT
WITH LOWS IN THE SINGLE DIGITS TO LOWER TEENS.
.LONG TERM...(FRIDAY THROUGH WEDNESDAY)
ISSUED AT 250 AM CST THU NOV 28 2013
THE LONG TERM WILL BEGIN TRANQUIL BUT WILL LIKELY END RATHER
ACTIVE AS A MAJOR PATTERN SHIFT UNFOLDS. HIGH PRESSURE OVER THE
GREAT LAKES WILL SLIDE EAST FRIDAY WITH WAA COMMENCING AT THE
START OF THE PERIOD. BREEZY SOUTHEAST WINDS WILL BRING HIGHS BACK
TO WHERE THEY SHOULD BE IN THE UPPER 20S TO MID 30S.
A WEAK CLIPPER SYSTEM WILL DIVE SOUTHEAST ACROSS NORTHERN LAKE
SUPERIOR FRIDAY NIGHT AND EARLY SATURDAY. FORECAST SOUNDINGS SHOW
SUFFICIENT MOISTENING IN THE LOWER LEVELS AFTER MIDNIGHT TO
SUPPORT A CHANCE OF FREEZING DRIZZLE OR FLURRIES OVER WESTERN
WISCONSIN. HOWEVER...KEPT PROBABILITIES RATHER LOW DUE TO THE
SOURCE REGION OF THIS MOISTURE BEING FROM THE SPRAWLING EASTERN
CONUS HIGH PRESSURE SYSTEM THAT DROVE A COLD FRONT THROUGH THE
GULF AND CUBA. NEEDLESS TO SAY...NOT A WHOLE LOT OF MOISTURE TO BE
FOUND ANYWHERE NEARBY.
SURFACE RIDGING WILL RETURN SATURDAY AND SUNDAY WITH TEMPERATURES
REMAINING NEAR NORMAL. MEANWHILE...A POTENT UPPER LOW TRAVERSING
ALASKA WILL DIVE SOUTHEAST ALONG THE BRITISH COLOMBIAN COAST INTO
THE PACIFIC NORTHWEST AND THE CENTRAL ROCKIES BY THE MIDDLE OF
NEXT WEEK. THIS WILL BE REPLACED WITH A 570DM RIDGE OVER ALASKA
MONDAY AND BUILDING HEIGHTS ACROSS THE CENTRAL AND EASTERN CONUS
FOR LATE WEEK. A SIZABLE CHUNK OF ARCTIC AIR WILL DISLODGE FROM
THE POLAR VORTEX AND SINK SOUTH TOWARD THE NORTHERN CONUS BY LATE
IN THE LONG TERM. FOLLOWED THE ECMWF/GEM/GFS ENSEMBLE SOLUTION
WITH A MORE ZONAL LOOK ACROSS THE NORTHERN TIER OF STATES AS
OPPOSED TO THE OPERATIONAL GFS WHICH SEEMED TOO AMPLIFIED DURING MID
TO LATE WEEK.
SOUTHERLY FLOW AHEAD OF THE WESTERN TROUGH AND MODEST ISENTROPIC
LIFT IN THE PRESENCE OF INCREASING MID LEVEL MOISTURE LOOKS
INCREASINGLY LIKELY WILL ALLOW FOR PERIODS OF LIGHT SNOW ALONG AN
EAST-WEST STATIONARY BOUNDARY FROM SUNDAY NIGHT THROUGH TUESDAY
NIGHT. DUE TO A SURFACE HIGH ANCHORED TO THE NORTH...EASTERLY
SURFACE FLOW WILL BRING A CONTINUED SUPPLY OF DRY BOUNDARY LAYER
AIR AND THUS AMOUNTS WILL BE LIGHT DURING THIS PERIOD.
SURFACE LOW ORGANIZING TO THE LEE OF THE ROCKIES IN ADVANCE OF
THE ROCKIES TROUGH MAY EJECT NORTHEAST TOWARD THE GREAT LAKES IN
THE WEDNESDAY NIGHT/THURSDAY TIMEFRAME. ECMWF BRINGS A PRETTY
IMPRESSIVE SYSTEM THROUGH WITH SIGNIFICANT ACCUMULATING SNOW. GEM
IS A BIT FURTHER SOUTH. REGARDLESS...FOLLOWING THIS POTENTIAL
STORM WILL BE AN EXPANSIVE INTRUSION OF ARCTIC AIR FOR MOST OF THE
CENTRAL AND WESTERN CONUS. THIS SIGNAL HAS BEEN SOLID IN CLIMATE
FORECASTING MODELS FOR WEEKS NOW AND AS CPC POINTS OUT IN THEIR
6-10 AND 8-14 DAY OUTLOOKS...PROBABILITY OF OCCUR RANCE IS VERY
HIGH. IF WE CAN GET A SNOWPACK DOWN BEFORE THIS ARRIVES...TEMPS
COULD BE 20-30+ DEGREES BELOW AVERAGE FOR EARLY DECEMBER.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z FRIDAY AFTERNOON)
ISSUED AT 1120 AM CST THU NOV 28 2013
VFR/MVFR CIGS MOVING SOUTHWARD ACROSS EASTERN MN MAY ALLOW FOR
SOME CIGS ARND 2.5 TEMPORARY THIS AFTN. THE BEST CHC OF MVFR CIGS
WILL OCCUR AT KSTC/KRNH DURING THE EARLY AFTN. ELSEWHERE...MORE
SCATTERED CLDS ARE EXPECTED. BY 22Z...ANY MINOR DAYTIME HEATING
WILL QUICKLY ERODE THE CLDS WITH ONLY CIRRUS EXPECTED AFT 00Z.
WINDS WILL QUICKLY BECOME NEAR CALM OVERNIGHT...BEFORE SHIFTING TO
THE S/SSE BY DAWN AND INCREASE TO 14-16 KTS IN WESTERN MN...AND
ARND 12 KTS IN EASTERN MN.
KMSP...
MVFR CIGS AS CLOSE AS KMIC WHICH MAY AFFECT THE AIRPORT GROUNDS
DURING THE EARLY AFTN HRS. BEST TIME FRAME WILL OCCUR BETWEEN
18-20Z WITH CIGS ARND 2.5K. OTHERWISE...SKIES WILL QUICKLY BECOME
CLR THIS EVENING WITH CIRRUS MOVING IN AFT MIDNIGHT. GUSTY WINDS
ARND 14-16 KTS THIS AFTN WILL BECOME CALM AND SHIFT TO THE SE BY
MORNING...BECOMING GUSTY AGAIN BY THE AFTN.
/OUTLOOK FOR KMSP/
SAT...VFR. SW WINDS AT 5-10KTS BECOMING W/NW DURING THE AFT/EVE.
SUN...VFR...POSSIBLY MVFR CIGS LATE WITH -SN. WINDS E/SE AT 5KTS.
MON...VFR WITH CHC OF MIX PREC LATE WITH MVFR CIGS. SE WNDS 10 KTS.
&&
.MPX WATCHES/WARNINGS/ADVISORIES...
MN...NONE.
WI...NONE.
&&
$$
SHORT TERM...MPG
LONG TERM...BORGHOFF
AVIATION...JLT
AREA FORECAST DISCUSSION
NWS TWIN CITIES/CHANHASSEN MN
529 AM CST THU NOV 28 2013
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 250 AM CST THU NOV 28 2013
MAIN ISSUE FOR THE SHORT TERM IS HOW LONG WILL IT TAKE FOR THE
CLOUDS TO CLEAR OUT TODAY. A 1018MB SFC LOW HAS BEEN MAKING SLOW BUT
STEADY PROGRESS ACROSS NRN IOWA OVERNIGHT AND WILL CONTINUE ON A
TRACK TOWARD SRN LAKE MICHIGAN BY THE AFTERNOON. AN INVERTED SFC
TROUGH HAS BEEN WORKING EAST ACROSS MN IN CONCERT WITH THE IOWA LOW
AND HAS HELPED MAINTAIN THE STRATUS NORTH OF THE LOW. BEHIND THIS
INVERTED TROUGH...ANOTHER CANADIAN HIGH IS BUILDING SOUTH ACROSS THE
DAKOTAS. RH TIME-HEIGHT PROFILES SHOW PLENTY OF DRYING AND
SUBSIDENCE OCCURRING AS THIS HIGH MOVES IN...WHICH IS WHY THE
QUESTION WITH THE CLOUDS IS HOW LONG DO THEY STICK AROUND. FOR
NOW...HAVE A RATHER CLOUDY FORECAST THROUGH 18Z...BUT QUICKLY START
TO IMPROVE THINGS FROM WEST TO EAST THIS AFTERNOON...IN LINE WITH
WHAT THE RAP 925-850 MB RH SHOWS.
ALTHOUGH THERE IS CURRENTLY A SEA OF LIGHT SNOW REPORTS ACROSS NRN
MN AND NODAK...THESE ARE NOT EXPECTED TO MAKE IT INTO THE MPX AREA.
THE REASON FOR THIS IS THAT SFC TEMPERATURES WHERE THE SNOW IS BEING
REPORTED RIGHT NOW ARE ALL IN THE LOW TO MID TEENS...WHICH MEANS UP
THERE...THE DENDRITIC GROWTH ZONE IS DOWN AT THE SURFACE AND EXTENDS
UP THROUGH THE CLOUD LAYER. ADD IN THE WEAK LIFT ALONG/AHEAD OF THE
INVERTED TROUGH WITH A DGZ ALL THE WAY DOWN TO THE SURFACE AND YOU
END UP WITH THE SCENARIO WHERE ALL CLOUDS HAVE SNOW. COMING DOWN TO
CENTRAL/SRN MN...SFC TEMPS DOWN HERE ARE ALL IN THE UPPER
TEENS/LOWER 20S...OUTSIDE OF THE DGZ. THE SHALLOWER DGZ THAT DOES
NOT EXTEND TO THE SFC HAS ALLOWED THE CLOUDS DOWN HERE TO REMAIN
SNOW FREE. CAA AT THE MOMENT IS NOT STRONG ENOUGH TO COOL OUR SFC
TEMPS DOWN INTO THE DGZ BEFORE WE START GETTING SOME SOLAR
HEATING...SO DO NOT ANTICIPATE THE SNOW/FLURRY REPORTS TO MAKE IT
MUCH FARTHER SOUTH THAN THEY CURRENTLY ARE.
THE COMBINATION OF WEAK CAA AND CLOUD COVER WILL AGAIN LIMIT THE
DIURNAL TEMPERATURE INCREASE AGAIN TODAY...WITH TEMPERATURES THIS
AFTERNOON ONLY EXPECTED TO INCREASE ABOUT 5 OR 10 DEGREES ABOVE
THEIR CURRENT VALUES THIS MORNING. TONIGHT...YET ANOTHER SFC RIDGE
AXIS WILL BE CENTERED ACROSS THE AREA...RESULTING IN ANOTHER NIGHT
WITH LOWS IN THE SINGLE DIGITS TO LOWER TEENS.
.LONG TERM...(FRIDAY THROUGH WEDNESDAY)
ISSUED AT 250 AM CST THU NOV 28 2013
THE LONG TERM WILL BEGIN TRANQUIL BUT WILL LIKELY END RATHER
ACTIVE AS A MAJOR PATTERN SHIFT UNFOLDS. HIGH PRESSURE OVER THE
GREAT LAKES WILL SLIDE EAST FRIDAY WITH WAA COMMENCING AT THE
START OF THE PERIOD. BREEZY SOUTHEAST WINDS WILL BRING HIGHS BACK
TO WHERE THEY SHOULD BE IN THE UPPER 20S TO MID 30S.
A WEAK CLIPPER SYSTEM WILL DIVE SOUTHEAST ACROSS NORTHERN LAKE
SUPERIOR FRIDAY NIGHT AND EARLY SATURDAY. FORECAST SOUNDINGS SHOW
SUFFICIENT MOISTENING IN THE LOWER LEVELS AFTER MIDNIGHT TO
SUPPORT A CHANCE OF FREEZING DRIZZLE OR FLURRIES OVER WESTERN
WISCONSIN. HOWEVER...KEPT PROBABILITIES RATHER LOW DUE TO THE
SOURCE REGION OF THIS MOISTURE BEING FROM THE SPRAWLING EASTERN
CONUS HIGH PRESSURE SYSTEM THAT DROVE A COLD FRONT THROUGH THE
GULF AND CUBA. NEEDLESS TO SAY...NOT A WHOLE LOT OF MOISTURE TO BE
FOUND ANYWHERE NEARBY.
SURFACE RIDGING WILL RETURN SATURDAY AND SUNDAY WITH TEMPERATURES
REMAINING NEAR NORMAL. MEANWHILE...A POTENT UPPER LOW TRAVERSING
ALASKA WILL DIVE SOUTHEAST ALONG THE BRITISH COLOMBIAN COAST INTO
THE PACIFIC NORTHWEST AND THE CENTRAL ROCKIES BY THE MIDDLE OF
NEXT WEEK. THIS WILL BE REPLACED WITH A 570DM RIDGE OVER ALASKA
MONDAY AND BUILDING HEIGHTS ACROSS THE CENTRAL AND EASTERN CONUS
FOR LATE WEEK. A SIZABLE CHUNK OF ARCTIC AIR WILL DISLODGE FROM
THE POLAR VORTEX AND SINK SOUTH TOWARD THE NORTHERN CONUS BY LATE
IN THE LONG TERM. FOLLOWED THE ECMWF/GEM/GFS ENSEMBLE SOLUTION
WITH A MORE ZONAL LOOK ACROSS THE NORTHERN TIER OF STATES AS
OPPOSED TO THE OPERATIONAL GFS WHICH SEEMED TOO AMPLIFIED DURING MID
TO LATE WEEK.
SOUTHERLY FLOW AHEAD OF THE WESTERN TROUGH AND MODEST ISENTROPIC
LIFT IN THE PRESENCE OF INCREASING MID LEVEL MOISTURE LOOKS
INCREASINGLY LIKELY WILL ALLOW FOR PERIODS OF LIGHT SNOW ALONG AN
EAST-WEST STATIONARY BOUNDARY FROM SUNDAY NIGHT THROUGH TUESDAY
NIGHT. DUE TO A SURFACE HIGH ANCHORED TO THE NORTH...EASTERLY
SURFACE FLOW WILL BRING A CONTINUED SUPPLY OF DRY BOUNDARY LAYER
AIR AND THUS AMOUNTS WILL BE LIGHT DURING THIS PERIOD.
SURFACE LOW ORGANIZING TO THE LEE OF THE ROCKIES IN ADVANCE OF
THE ROCKIES TROUGH MAY EJECT NORTHEAST TOWARD THE GREAT LAKES IN
THE WEDNESDAY NIGHT/THURSDAY TIMEFRAME. ECMWF BRINGS A PRETTY
IMPRESSIVE SYSTEM THROUGH WITH SIGNIFICANT ACCUMULATING SNOW. GEM
IS A BIT FURTHER SOUTH. REGARDLESS...FOLLOWING THIS POTENTIAL
STORM WILL BE AN EXPANSIVE INTRUSION OF ARCTIC AIR FOR MOST OF THE
CENTRAL AND WESTERN CONUS. THIS SIGNAL HAS BEEN SOLID IN CLIMATE
FORECASTING MODELS FOR WEEKS NOW AND AS CPC POINTS OUT IN THEIR
6-10 AND 8-14 DAY OUTLOOKS...PROBABILITY OF OCCUR RANCE IS VERY
HIGH. IF WE CAN GET A SNOWPACK DOWN BEFORE THIS ARRIVES...TEMPS
COULD BE 20-30+ DEGREES BELOW AVERAGE FOR EARLY DECEMBER.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z FRIDAY MORNING)
ISSUED AT 519 AM CST THU NOV 28 2013
HIGH PRESSURE WILL BE MOVING ACROSS THE TERMINALS THIS
PERIOD...RESULTING IN YET ANOTHER QUIET TAF PERIOD. MAIN ISSUE FOR
TODAY IS WHEN WILL THE VFR STRATUS CLEAR. ALREADY SEEING SOME
CLEARING DEVELOP NORTH OF FARGO...AND RAP 925-850 MB RH SHOWS
CLEARING DEVELOPING FROM THIS AREA QUICKLY AFTER 15Z OR SO.
CURRENT TAFS LOOKED TO HAVE THINGS TIMED WELL WITH RESPECT TO
CLEARING SO MADE FEW CHANGES. WILL SEE NW WINDS TODAY THAT WILL GO
CALM OVERNIGHT WITH THE HIGH AS SE WINDS RETURN LATE AT MN
TERMINALS.
KMSP...ABOUT THE ONLY POSSIBLE DEVIATION THAT COULD BE SEEN FROM
CURRENT TAF WOULD BE A LATER SCATTERING OUT OF VFR CIGS THAN
CURRENTLY INDICATED...BUT AT 5K FT...THEY WILL BE OF MINIMAL IMPACT.
/OUTLOOK FOR KMSP/
FRI...VFR. WINDS SE AT 5-10KTS.
SAT...VFR. SW WINDS AT 5-10KTS BECOMING W/NW DURING THE AFT/EVE.
SUN...VFR. WINDS E/SE AT 5KTS.
&&
.MPX WATCHES/WARNINGS/ADVISORIES...
MN...NONE.
WI...NONE.
&&
$$
SHORT TERM...MPG
LONG TERM...BORGHOFF
AVIATION...MPG
AREA FORECAST DISCUSSION
NWS TWIN CITIES/CHANHASSEN MN
414 AM CST THU NOV 28 2013
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 250 AM CST THU NOV 28 2013
MAIN ISSUE FOR THE SHORT TERM IS HOW LONG WILL IT TAKE FOR THE
CLOUDS TO CLEAR OUT TODAY. A 1018MB SFC LOW HAS BEEN MAKING SLOW BUT
STEADY PROGRESS ACROSS NRN IOWA OVERNIGHT AND WILL CONTINUE ON A
TRACK TOWARD SRN LAKE MICHIGAN BY THE AFTERNOON. AN INVERTED SFC
TROUGH HAS BEEN WORKING EAST ACROSS MN IN CONCERT WITH THE IOWA LOW
AND HAS HELPED MAINTAIN THE STRATUS NORTH OF THE LOW. BEHIND THIS
INVERTED TROUGH...ANOTHER CANADIAN HIGH IS BUILDING SOUTH ACROSS THE
DAKOTAS. RH TIME-HEIGHT PROFILES SHOW PLENTY OF DRYING AND
SUBSIDENCE OCCURRING AS THIS HIGH MOVES IN...WHICH IS WHY THE
QUESTION WITH THE CLOUDS IS HOW LONG DO THEY STICK AROUND. FOR
NOW...HAVE A RATHER CLOUDY FORECAST THROUGH 18Z...BUT QUICKLY START
TO IMPROVE THINGS FROM WEST TO EAST THIS AFTERNOON...IN LINE WITH
WHAT THE RAP 925-850 MB RH SHOWS.
ALTHOUGH THERE IS CURRENTLY A SEA OF LIGHT SNOW REPORTS ACROSS NRN
MN AND NODAK...THESE ARE NOT EXPECTED TO MAKE IT INTO THE MPX AREA.
THE REASON FOR THIS IS THAT SFC TEMPERATURES WHERE THE SNOW IS BEING
REPORTED RIGHT NOW ARE ALL IN THE LOW TO MID TEENS...WHICH MEANS UP
THERE...THE DENDRITIC GROWTH ZONE IS DOWN AT THE SURFACE AND EXTENDS
UP THROUGH THE CLOUD LAYER. ADD IN THE WEAK LIFT ALONG/AHEAD OF THE
INVERTED TROUGH WITH A DGZ ALL THE WAY DOWN TO THE SURFACE AND YOU
END UP WITH THE SCENARIO WHERE ALL CLOUDS HAVE SNOW. COMING DOWN TO
CENTRAL/SRN MN...SFC TEMPS DOWN HERE ARE ALL IN THE UPPER
TEENS/LOWER 20S...OUTSIDE OF THE DGZ. THE SHALLOWER DGZ THAT DOES
NOT EXTEND TO THE SFC HAS ALLOWED THE CLOUDS DOWN HERE TO REMAIN
SNOW FREE. CAA AT THE MOMENT IS NOT STRONG ENOUGH TO COOL OUR SFC
TEMPS DOWN INTO THE DGZ BEFORE WE START GETTING SOME SOLAR
HEATING...SO DO NOT ANTICIPATE THE SNOW/FLURRY REPORTS TO MAKE IT
MUCH FARTHER SOUTH THAN THEY CURRENTLY ARE.
THE COMBINATION OF WEAK CAA AND CLOUD COVER WILL AGAIN LIMIT THE
DIURNAL TEMPERATURE INCREASE AGAIN TODAY...WITH TEMPERATURES THIS
AFTERNOON ONLY EXPECTED TO INCREASE ABOUT 5 OR 10 DEGREES ABOVE
THEIR CURRENT VALUES THIS MORNING. TONIGHT...YET ANOTHER SFC RIDGE
AXIS WILL BE CENTERED ACROSS THE AREA...RESULTING IN ANOTHER NIGHT
WITH LOWS IN THE SINGLE DIGITS TO LOWER TEENS.
.LONG TERM...(FRIDAY THROUGH WEDNESDAY)
ISSUED AT 250 AM CST THU NOV 28 2013
THE LONG TERM WILL BEGIN TRANQUIL BUT WILL LIKELY END RATHER
ACTIVE AS A MAJOR PATTERN SHIFT UNFOLDS. HIGH PRESSURE OVER THE
GREAT LAKES WILL SLIDE EAST FRIDAY WITH WAA COMMENCING AT THE
START OF THE PERIOD. BREEZY SOUTHEAST WINDS WILL BRING HIGHS BACK
TO WHERE THEY SHOULD BE IN THE UPPER 20S TO MID 30S.
A WEAK CLIPPER SYSTEM WILL DIVE SOUTHEAST ACROSS NORTHERN LAKE
SUPERIOR FRIDAY NIGHT AND EARLY SATURDAY. FORECAST SOUNDINGS SHOW
SUFFICIENT MOISTENING IN THE LOWER LEVELS AFTER MIDNIGHT TO
SUPPORT A CHANCE OF FREEZING DRIZZLE OR FLURRIES OVER WESTERN
WISCONSIN. HOWEVER...KEPT PROBABILITIES RATHER LOW DUE TO THE
SOURCE REGION OF THIS MOISTURE BEING FROM THE SPRAWLING EASTERN
CONUS HIGH PRESSURE SYSTEM THAT DROVE A COLD FRONT THROUGH THE
GULF AND CUBA. NEEDLESS TO SAY...NOT A WHOLE LOT OF MOISTURE TO BE
FOUND ANYWHERE NEARBY.
SURFACE RIDGING WILL RETURN SATURDAY AND SUNDAY WITH TEMPERATURES
REMAINING NEAR NORMAL. MEANWHILE...A POTENT UPPER LOW TRAVERSING
ALASKA WILL DIVE SOUTHEAST ALONG THE BRITISH COLOMBIAN COAST INTO
THE PACIFIC NORTHWEST AND THE CENTRAL ROCKIES BY THE MIDDLE OF
NEXT WEEK. THIS WILL BE REPLACED WITH A 570DM RIDGE OVER ALASKA
MONDAY AND BUILDING HEIGHTS ACROSS THE CENTRAL AND EASTERN CONUS
FOR LATE WEEK. A SIZABLE CHUNK OF ARCTIC AIR WILL DISLODGE FROM
THE POLAR VORTEX AND SINK SOUTH TOWARD THE NORTHERN CONUS BY LATE
IN THE LONG TERM. FOLLOWED THE ECMWF/GEM/GFS ENSEMBLE SOLUTION
WITH A MORE ZONAL LOOK ACROSS THE NORTHERN TIER OF STATES AS
OPPOSED TO THE OPERATIONAL GFS WHICH SEEMED TOO AMPLIFIED DURING MID
TO LATE WEEK.
SOUTHERLY FLOW AHEAD OF THE WESTERN TROUGH AND MODEST ISENTROPIC
LIFT IN THE PRESENCE OF INCREASING MID LEVEL MOISTURE LOOKS
INCREASINGLY LIKELY WILL ALLOW FOR PERIODS OF LIGHT SNOW ALONG AN
EAST-WEST STATIONARY BOUNDARY FROM SUNDAY NIGHT THROUGH TUESDAY
NIGHT. DUE TO A SURFACE HIGH ANCHORED TO THE NORTH...EASTERLY
SURFACE FLOW WILL BRING A CONTINUED SUPPLY OF DRY BOUNDARY LAYER
AIR AND THUS AMOUNTS WILL BE LIGHT DURING THIS PERIOD.
SURFACE LOW ORGANIZING TO THE LEE OF THE ROCKIES IN ADVANCE OF
THE ROCKIES TROUGH MAY EJECT NORTHEAST TOWARD THE GREAT LAKES IN
THE WEDNESDAY NIGHT/THURSDAY TIMEFRAME. ECMWF BRINGS A PRETTY
IMPRESSIVE SYSTEM THROUGH WITH SIGNIFICANT ACCUMULATING SNOW. GEM
IS A BIT FURTHER SOUTH. REGARDLESS...FOLLOWING THIS POTENTIAL
STORM WILL BE AN EXPANSIVE INTRUSION OF ARCTIC AIR FOR MOST OF THE
CENTRAL AND WESTERN CONUS. THIS SIGNAL HAS BEEN SOLID IN CLIMATE
FORECASTING MODELS FOR WEEKS NOW AND AS CPC POINTS OUT IN THEIR
6-10 AND 8-14 DAY OUTLOOKS...PROBABILITY OF OCCUR RANCE IS VERY
HIGH. IF WE CAN GET A SNOWPACK DOWN BEFORE THIS ARRIVES...TEMPS
COULD BE 20-30+ DEGREES BELOW AVERAGE FOR EARLY DECEMBER.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z THURSDAY EVENING)
ISSUED AT 1025 PM CST WED NOV 27 2013
A BKN-OVC DECK FROM 5KFT-7KFT WILL PREVAIL OVERNIGHT...AS MVFR
LEVEL CLOUDS APPROACH FROM THE NORTH/WEST. SAID CLOUDS ARE
EXPECTED TO ENTER WEST CENTRAL MN /KAXN/ BY DAYBREAK...AND
GRADUALLY SNAKE SOUTH AND EAST /TOWARD KRWF/ DURING THE MORNING.
THE CLOUDS SHOULD BECOME MORE TRANSPARENT DURING THE DAYTIME
HOWEVER...SO HAVE ONLY INCLUDED A SCATTERED GROUP AT KMSP...BUT
KEAU/KRNH LIKELY SEEING BKN-OVC MVFR CIGS THROUGH A GOOD PORTION
OF THE DAY. LIGHT AND VARIABLE WINDS OVERNIGHT BECOME
WEST/NORTHWEST ON THURSDAY AND INCREASE TO 10-15KTS IN THE WAKE OF
THE TROUGH.
KMSP...
A 5000FT CIG WILL PREVAIL INTO THURSDAY...WITH A POSSIBILITY FOR
MVFR LEVEL CLOUDS BETWEEN 18Z THU AND 00Z FRI. HAVE INCLUDED A SCT
MENTION FOR NOW. LIGHT AND VARIABLE WINDS OVERNIGHT SHIFT TO THE
NORTHWEST BY 14Z THURSDAY /AND GUST TO AROUND 15KTS DURING THE
AFTERNOON/.
/OUTLOOK FOR KMSP/
FRI...VFR. WINDS SE AT 5-10KTS.
SAT...VFR. SW WINDS AT 5-10KTS BECOMING W/NW DURING THE AFT/EVE.
SUN...VFR WITH MVFR AND -SN POSSIBLE LATE. WINDS E/SE AT 5KTS.
&&
.MPX WATCHES/WARNINGS/ADVISORIES...
MN...NONE.
WI...NONE.
&&
$$
SHORT TERM...MPG
LONG TERM...BORGHOFF
AVIATION...LS
AREA FORECAST DISCUSSION
NWS TWIN CITIES/CHANHASSEN MN
1023 PM CST WED NOV 27 2013
.UPDATE...FOR 06Z AVIATION DISCUSSION BELOW
&&
.SHORT TERM...(THIS EVENING THROUGH THURSDAY)
ISSUED AT 215 PM CST WED NOV 27 2013
EARLY AFTERNOON WATER VAPOR IMAGERY TOGETHER WITH GFS 27.12 HEIGHTS
AND WINDS IMMEDIATELY IDENTIFIED A LONG WAVE TROUGH ACROSS THE
EASTERN CONUS...WITH A CYCLONE DOWNSTREAM OF THIS TROUGH AXIS.
NORTHWEST FLOW PREVAILED ACROSS THE CENTRAL CONUS UPSTREAM OF THE
TROUGH AXIS. A WEAK SHORTWAVE ALONG THE ND/MN BORDER WAS EMBEDDED IN
THIS NORTHWEST FLOW. WARM AIR ADVECTION AHEAD IF THIS SHORTWAVE
TOGETHER WITH THE UPPER LEVEL DYNAMICS ASSOCIATED WITH THE 5M/HR
HEIGHT FALLS WERE THE DRIVING FORCE BEHIND AN AREA OF SNOW ACROSS
NORTHERN MINNESOTA.
THIS EVENING THE FORCING WILL WEAKEN...BUT SNOW SHOULD CONTINUE TO
SPREAD SOUTHEASTWARD INTO NORTHERN WISCONSIN. THE NORTHEASTERN
COUNTIES IN THE CWA WILL BE RIGHT ON THE EDGE OF THIS SNOW...BUT
FORECAST SOUNDINGS FOR EAU CLAIRE AND NEW RICHMOND WOULD SUPPORT AT
LEAST A FEW HOURS OF SNOW. THE LOW LEVEL DRY AIR WILL DELAY THE
ONSET UNTIL CLOSER TO 00Z THIS EVENING. SNOW TOTALS WILL BE LESS
THAN AN INCH...AND SHOULD TAPER OFF TO FLURRIES BY THURSDAY MORNING.
THE CHALLENGE FOR THURSDAYS FORECAST WAS THE CLOUD COVER. INCREASED
IT SLIGHTLY BASED OFF THE 0-1RH FROM BOTH THE NAM AND RAP WHICH SEEM
TO HAVE A GOOD HANDLE ON THE STRATUS CURRENTLY ENTERING NORTHERN
NORTH DAKOTA. ALSO LOWERED HIGH TEMPS A COUPLE OF DEGREES BECAUSE OF
THE INCREASED CLOUD COVER.
.LONG TERM...(THURSDAY NIGHT THROUGH WEDNESDAY)
ISSUED AT 215 PM CST WED NOV 27 2013
BIG CHGS ARE EXPECTED NEXT WEEK AS A SIGNIFICANT ARCTIC AIR MASS
SURGES SOUTHWARD ACROSS THE WESTERN CONUS...AND EVENTUALLY TAKING
HOLD OF MOST OF THE U.S...WITH THE EXCEPTION IN THE DEEP SE.
CURRENT LONG WAVE PATTERN REMAINS FROM THE NW ACROSS THE UPPER
MIDWEST ALONG WITH A SPLIT FLOW REGIME FOR THE REMAINDER OF THE
CONUS. THE SOUTHERN STREAM HAS BEEN THE MOST ACTIVE IN RECENT
WEEKS...TAKING THE BULK OF THE SIGNIFICANT WX TRACKS SOUTH AND
EAST OF THE UPPER MIDWEST. ALTHOUGH SOME TIMING AND STRENGTH
PARAMETERS REMAIN UNCLEAR IN THE DETERMINISTIC RUNS FROM BOTH THE
EC/GFS...THERE REMAINS ONE THEME...A SIGNIFICANT COLD AIR MASS
WILL INVADE MOST OF THE U.S. STARTING THIS WEEKEND IN THE PACIFIC
NW...AND EVENTUALLY THE ROCKIES/PLAINS/GREAT LAKES BY THE
FOLLOWING WEEKEND.
USUALLY MODELS ARE TOO FAST ON PATTERN CHGS...AND THIS IS EVIDENT
WITH EACH MODEL RUN. ALTHOUGH THE EC HAS BEEN THE STRONGEST ON THE
DEEP TROUGH DEVELOPING ACROSS MOST OF THE WESTERN/CENTRAL PART OF
THE U.S. BY LATE NEXT WEEK...THE ENSEMBLE MEANS /EC & GFS/ HAVE
CONTINUED TO KEEP A MORE PROGRESSIVE WX PATTERN. EVEN THE LATEST
EC 12Z/27 RUN HAS A MORE PRONOUNCED DEEP TROUGH ACROSS THE
NORTHERN ROCKIES BY THE END OF NEXT WEEK COMPARED TO THE 50H
ENSEMBLE MEAN.
BASICALLY WITH THE STRONGER AND DEEPER TROUGH...STORM SYSTEMS WILL
LIKELY BE SLOWER ON THE ONSET OF SFC LOW /BOMBS/ DEVELOPING ACROSS
THE PLAINS. OVER THE PAST 3-5 RUNS OF THE EC...THE SFC LOW AND
ASSOCIATED ARCTIC BOUNDARY KEEPS GETTING PUSHED BACK IN TIME ON
THE EVOLUTION OF A STRONG STORM SYSTEM IN THE PLAINS. THIS WILL
LIKELY KEEP OUR REGION UNEVENTFUL UNTIL LATE IN THE PERIOD...AND
POSSIBLY OUTSIDE OUR 7 DAY FORECAST IF THE TROUGH IN THE WEST
CONTINUES TO DEEPEN. IN ADDITION TO THE SLOWER PACE OF THE STORM
SYSTEM MOVING OUT INTO THE PLAINS...THE LARGE AREA OF ARCTIC HIGH
PRESSURE CIRCULATING FROM THE EASTERN CANADA...AND ACROSS THE
GREAT LAKES /EAST & NE FLOW IN THE BOUNDARY LAYER/...KEEPS OUR
REGION RELATIVELY DRY. THEREFORE...I AM NOT CONFIDENT ON ANY CHC
OF PRECIPITATION NEXT WEEK UNTIL THIS SYSTEM MOVES OUT INTO THE
PLAINS.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z THURSDAY EVENING)
ISSUED AT 1025 PM CST WED NOV 27 2013
A BKN-OVC DECK FROM 5KFT-7KFT WILL PREVAIL OVERNIGHT...AS MVFR
LEVEL CLOUDS APPROACH FROM THE NORTH/WEST. SAID CLOUDS ARE
EXPECTED TO ENTER WEST CENTRAL MN /KAXN/ BY DAYBREAK...AND
GRADUALLY SNAKE SOUTH AND EAST /TOWARD KRWF/ DURING THE MORNING.
THE CLOUDS SHOULD BECOME MORE TRANSPARENT DURING THE DAYTIME
HOWEVER...SO HAVE ONLY INCLUDED A SCATTERED GROUP AT KMSP...BUT KEAU/KRNH
LIKELY SEEING BKN-OVC MVFR CIGS THROUGH A GOOD PORTION OF THE DAY.
LIGHT AND VARIABLE WINDS OVERNIGHT BECOME WEST/NORTHWEST ON
THURSDAY AND INCREASE TO 10-15KTS IN THE WAKE OF THE TROUGH.
KMSP...
A 5000FT CIG WILL PREVAIL INTO THURSDAY...WITH A POSSIBILITY FOR MVFR
LEVEL CLOUDS BETWEEN 18Z THU AND 00Z FRI. HAVE INCLUDED A SCT
MENTION FOR NOW. LIGHT AND VARIABLE WINDS OVERNIGHT SHIFT TO THE NORTHWEST
BY 14Z THURSDAY /AND GUST TO AROUND 15KTS DURING THE AFTERNOON/.
/OUTLOOK FOR KMSP/
FRI...VFR. WINDS SE AT 5-10KTS.
SAT...VFR. SW WINDS AT 5-10KTS BECOMING W/NW DURING THE AFT/EVE.
SUN...VFR WITH MVFR AND -SN POSSIBLE LATE. WINDS E/SE AT 5KTS.
&&
.MPX WATCHES/WARNINGS/ADVISORIES...
MN...NONE.
WI...NONE.
&&
$$
SHORT TERM...JRB
LONG TERM...JLT
AVIATION...LS
AREA FORECAST DISCUSSION...UPDATED AVIATION
NWS ST LOUIS MO
554 AM CST Thu Nov 28 2013
.SHORT TERM: (Through Late This Afternoon)
Issued at 327 AM CST Thu Nov 28 2013
Southerly winds ahead of low pressure zipping from N IA into MI
today will bring a brief shot of warm air into the CWA this morning,
which will then be followed by a secondary surge of cold air during
the afternoon and into the evening. Primary question for this
Thanksgiving Day is how warm to go for high temperatures given the
see-saw nature of the temperature advection during the day. Have
followed trend of going forecasts in heading towards the warm side
of guidance, especially along and south of the I-70 corridor in
Missouri where thermal ridge ahead of cold front, mixing, and strong
sunshine should all combine to have their greatest impact. In
northern sections of the CWA it may be that temps will make a fairly
substantial jump this morning, but additional temp climb during the
afternoon will struggle as the return of colder air trumps the
effects of afternoon sunshine.
Have also gone with lots of sunshine today. Will need to keep an eye
on post frontal stratus that is making a strong southward surge into
E NE early today, but if all of the forecast soundings and RH
guidance is to be believed the dry airmass and mixing will cause
this deck to erode before reaching our CWA.
Truett
.LONG TERM: (Tonight through Wednesday)
Issued at 327 AM CST Thu Nov 28 2013
(Tonight through Saturday Night)
Now that the energy along the East Coast has moved offshore, what
is left is a broad low amplitude trough across the ern half of the
country and nw flow along the Canadian border funneling into the ern
trough. There is split flow along the West Coast with a closed low off
the srn CA coast. The NW flow keeps the parade of cold fronts coming
every 48 hrs or so with the most recent bndry exiting the CWA early
this evening. The next short wave and assoc cold front is fcst for
Saturday night. The fronts are passing with such frequency that the
atmosphere does not have much chance to recover. Therefore, there isn`t
much moisture to work with and the fronts pass quietly with no precip
and little to no cloud cover. This front will fail to tap a true arctic
airmass and shouldn`t be anymore than a subtle wind shift. There is
another short wave that is expected to pass thru the area late this
week. The vort max is expected to move across srn MO/IL Friday night
into Saturday morning. Due to limited moisture, no precip is expected
with this feature.
Temps will be slightly cooler on Friday behind the cold front. I generally
used a blend of MOS guidance but, tended to favor the warmer MAV. Temps
are expected to bounce back again on Saturday in advance of the next
cold front. Generally used a blend of guidance but went on the warm
side of guidance across cntrl and e cntrl MO due to the synoptic set
up for a decent warm up.
(Sunday thru Wednesday)
Model consensus agrees that NW flow continues thru Monday and then
transitions to SW flow by Wednesday. The problem is the path they
take from NW to SW flow. Return flow begins Tuesday. The column
eventually moistens sufficiently for clouds and rain chances
beginning Tuesday night and continuing thru Wednesday. Due to model
differences, this is a lower confidence fcst.
Highs are expected to be 5-10 degrees cooler on Sunday after the
Saturday night FROPA. A slow warming trend begins on Monday that
continues thru Wednesday with temps near seasonal norms by Tuesday
and Wednesday.
2%
&&
.AVIATION: (For the 12z TAFs through 12z Friday Morning)
Issued at 550 AM CST Thu Nov 28 2013
Latest RUC data continues to indicate low level jet over the
region early this morning, with southwest winds in the 40-45kt
range. LLWS was introduced to the TAFs several hours ago because
of this, and will continue the LLWS in the 12z TAFs until 15z when
mixing begins to lessen this low level flow.
Surface low pressure is allowing warm air to work into the region
early today on south-southwest winds, but the cold front trailing
the low has now dropped into NW MO. This front will work across
the CWA later this afternoon, and 12z TAFs attempt to reflect the
wind shift associated with the front.
With extremely dry ams forecast in the lower levels of the AMS
over the mid-Mississippi Valley, any cloudiness should be limited
to some patchy high level cirrus. Will need to keep an eye on
stratus dropping across NE and behind the cold front, but all
indications are that these clouds will erode before reaching our CWA.
Specifics for KSTL: Low level wind shear threat should subside
around 15z. Otherwise, it appears favorable flying conditions are
in the offing for the KSTL area, with clouds limited to a bit of
patchy cirrus. Surface winds will slowly veer to the west during
the morning, and then to the northwest this afternoon with the
passage of the aforementioned cold front.
Truett
&&
.LSX WATCHES/WARNINGS/ADVISORIES:
MO...NONE.
IL...NONE.
&&
$$
WFO LSX
AREA FORECAST DISCUSSION
NWS HASTINGS NE
1144 AM CST THU NOV 28 2013
.UPDATE...
ISSUED AT 913 AM CST THU NOV 28 2013
WITH THICK STRATUS EVIDENT ON SATELLITE IMAGERY AND LATEST RAP
COMING IN WITH PESSIMISTIC CONDITIONS FOR THE REST OF THE
DAY...WENT AHEAD AND FURTHER INCREASED CLOUD COVER FROM PREVIOUS
UPDATE AS WELL AS DROPPED FORECAST HIGH TEMPERATURES ABOUT 5
DEGREES ACROSS THE BOARD. OTHERWISE...NO ADDITIONAL CHANGES
NECESSARY AT THIS TIME.
UPDATE ISSUED AT 749 AM CST THU NOV 28 2013
BASED ON LATEST SHORTWAVE IR SATELLITE AND MODEL TRENDS...
ANTICIPATE WE WILL NEED TO MAKE SOME SUBSTANTIAL CHANGES TO THE
FCST TODAY AND POSSIBLY INTO TONIGHT AND TOMORROW. THESE CHANGES
WILL INVOLVE MORE CLOUDS AND COOLER TEMPS...PROBABLY NOT BECOMING
AS WARM AS THOUGHT THE LAST FEW DAYS AND WE SAW THIS AS A
POTENTIAL OPTION EARLIER THIS WEEK. IT/S TOUGH TO FCST FAR IN
ADVANCE THOUGH.
THERE IS AN EXTENSIVE BANK OF STRATUS RACING S TO THE KS-NEB
BORDER AT THIS TIME AND IT EXTENDS ALL THE WAY UP INTO THE
CANADIAN PRAIRIES. BELIEVE THIS IS GOING TO BE A FCST PROBLEM THRU
SUNSET TOMORROW AS IT WILL BE STUCK IN A THERMAL TROF /COLD
POCKET/ AND WILL RESIST EROSION. WE REALLY NEED WARM AIR ADVECTION
TO GET RID OF IT AND THAT WILL NOT HAPPEN UNTIL LATE TONIGHT OR
TOMORROW.
SO THE FCST SKY HAS BEEN TURNED SIGNIFICANTLY MORE PESSIMISTIC
THRU MIDDAY AND EXPECT WE WILL NEED TO PUSH THIS FURTHER INTO THE
AFTERNOON PENDING THE LATEST SATELLITE TRENDS.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 332 AM CST THU NOV 28 2013
OVERNIGHT UPPER AIR ANALYSIS INDICATES MID TO UPPER LEVEL
TROUGHING OVER THE EASTERN CONUS...WITH A RIDGE OVER THE WEST AND
A MID LEVEL LOW OVER THE PACIFIC OFF THE CALIFORNIA COAST. A
SUBTLE MID LEVEL PERTURBATION IS ALSO NOTED OVER SOUTHERN
MINNESOTA...MOVING SOUTHEAST. MID TO UPPER LEVEL JET ENERGY
EXTENDS FROM SOUTH CENTRAL CANADA...SOUTHEAST INTO THE CENTRAL
CONUS...AND FINALLY EAST AND NORTHEAST ALONG THE EASTERN CONUS
INTO SOUTHEASTERN CANADA. MID TO UPPER LEVEL FLOW OVER OUR AREA
MAXES OUT AT AROUND 70KTS BETWEEN 300MB AND 200MB PER 00Z SOUNDING
DATA FROM KLBF AND KOAX. WATER VAPOR IMAGERY INDICATES INCREASED
VALUES OF MID LEVEL MOISTURE EXTENDING ALONG THE BACK SIDE OF THE
WEST COAST RIDGE...AS WELL AS FROM THE PACIFIC EASTWARD INTO
MEXICO AND THE SOUTHERN PLAINS. MID LEVEL MOISTURE OVER OUR AREA
HOWEVER REMAINS FAIRLY LIMITED. AT THE SURFACE...AN AREA OF LOW
BAROMETRIC PRESSURE EXISTS OVER NORTHWEST IOWA JUST AHEAD OF THE
AFOREMENTIONED MID LEVEL PERTURBATION...WITH AN ASSOCIATED COLD
FRONT EXTENDING FROM WESTERN IOWA INTO SOUTHEASTERN NEBRASKA AND
NORTHERN KANSAS. THIS FRONT HAS CLEARED MOST ALL OF OUR CWA AND AS
A RESULT...THE LOW LEVEL WIND FIELD ACROSS OUR AREA REMAINS FROM
THE NORTH/NORTHWEST.
GUIDANCE FROM THE NAM...OPERATIONAL GFS...EC AND SREF-MEAN ALL
SUGGEST NORTHWESTERLY MID TO UPPER LEVEL FLOW WILL PERSIST OVER
OUR AREA THROUGH THE NEXT 24 HOURS AS THE EASTERN CONUS TROUGH AND
WESTERN CONUS RIDGE BOTH TREK EAST. THE MID LEVEL
PERTURBATION...CURRENTLY OVER SOUTHERN MINNESOTA...IS EXPECTED TO
CONTINUE MOVING SOUTHEAST THROUGH THE NEXT 24 HOURS...WITH NO
OTHER MID LEVEL SHORTWAVES/PERTURBATIONS EXPECTED TO IMPACT THE
REGION. AT THE SURFACE...THE AREA OF LOW BAROMETRIC
PRESSURE...CURRENTLY OVER NORTHWEST IOWA...SHOULD ALSO CONTINUE
MOVING TO THE EAST/SOUTHEAST THROUGH THE NEXT 24 HOURS...WITH THE
ASSOCIATED LOW LEVEL BAROCLINIC ZONE PUSHING FARTHER
SOUTH/SOUTHEAST ACROSS THE PLAINS. THE LOW LEVEL WIND FIELD ACROSS
OUR AREA SHOULD REMAIN FROM THE NORTH/NORTHWEST THROUGH MUCH OF
TODAY AS A RESULT. THAT BEING SAID...GUIDANCE SUGGESTS THE PASSAGE
OF A SURFACE RIDGE TO EAST SHOULD ALLOW FOR LOW LEVEL RETURN FLOW
ACROSS OUR AREA DURING THE OVERNIGHT HOURS TONIGHT.
WITH AN OVERALL LACK IN OMEGA EXPECTED OVER OUR AREA...DRY
CONDITIONS ARE CURRENTLY FORECAST THROUGH THE NEXT 24 HOURS.
SATELLITE IMAGERY INDICATES A BAND OF STRATUS OVER MUCH OF THE
NORTHERN PLAINS THIS MORNING AND THIS STRATUS IS ADVANCING TO THE
SOUTH...ABOUT 150 MILES NORTH OF THE AFOREMENTIONED SURFACE FRONT.
GUIDANCE FROM THE NAM AND RAP BOTH SHOW THIS STRATUS...WITH HIGH
RELATIVE HUMIDITY VALUES AT 925MB NOTED ON PLAN VIEW
MAPS...INFILTRATING OUR NORTH/NORTHEASTERN CWA JUST PRIOR TO
SUNRISE THIS MORNING...BUT DISSIPATING POST-SUNRISE AS DIABATIC
HEATING RESULTS IN INCREASED BOUNDARY LAYER HEIGHT AND MIXING.
WENT AHEAD AND PLAYED PRETTY CLOSE TO NAM AND RAP GUIDANCE FOR THE
CLOUD FORECAST THROUGH THE FIRST PART OF THE SHORT TERM FORECAST
PERIOD...WITH THIS STRATUS EXPECTED TO IMPACT OUR NORTH/NORTHEAST
BY 10Z OR 11Z THIS MORNING...AND THEN DISSIPATE BY 15Z OR 16Z.
WITH LOW LEVEL RETURN FLOW INFILTRATING THE REGION TONIGHT...THERE
ARE INDICATIONS OF ISENTROPIC UPGLIDE AND SATURATION...PRIMARILY
ALONG THE 275-285K SURFACES...OVER THE HIGH PLAINS OF KANSAS AND
NEBRASKA. ALTHOUGH IT APPEARS MUCH OF OUR CWA SHOULD BE SPARED
FROM ANY STRATUS DEVELOPMENT THROUGH 12Z FRIDAY...925MB RELATIVE
HUMIDITY PLAN VIEW MAPS FROM THE NAM...OPERATIONAL GFS AND EC ALL
SUGGEST OUR EXTREME WEST/SOUTHWEST COULD ACTUALLY OBSERVE QUITE A
BIT OF CLOUD COVER TOWARDS SUNRISE FRIDAY AS THE EASTERN PERIPHERY
OF THE HIGH PLAINS STRATUS CLIPS THE AREA. WENT AHEAD WITH A
BROKEN CEILING ACROSS OUR EXTREME WEST/SOUTHWEST BY 12Z FRIDAY AS
A RESULT.
THE INTRUSION OF A COOLER LOW LEVEL AIRMASS BEHIND THE LOW LEVEL
BAROCLINIC ZONE SHOULD RESULT IN A COOLER DAY TODAY WHEN COMPARED
TO WEDNESDAY. HIGH TEMPERATURES GENERALLY IN THE MID 30S ACROSS
OUR NORTH...AND INTO THE MID 40S ACROSS OUR SOUTH...ARE FORECAST
FOR TODAY AS A RESULT. IT MIGHT OTHERWISE BE REASONABLE TO THINK
TONIGHT WILL BE COOLER WHEN COMPARED TO EARLY THIS MORNING...BUT
WITH LOW LEVEL RETURN FLOW EXPECTED TO INFILTRATE OUR AREA DURING
THE OVERNIGHT HOURS...OVERNIGHT LOWS TONIGHT SHOULD ACTUALLY BE
PRETTY CLOSE TO WHAT WE ARE EXPECTING EARLY THIS MORNING.
.LONG TERM...(FRIDAY THROUGH WEDNESDAY)
ISSUED AT 332 AM CST THU NOV 28 2013
THE FIRST PART OF THE LONG TERM FORECAST IS DRY WITH ABOVE NORMAL
TEMPERATURES...AFTER WHICH A MORE UNSETTLED...COLDER AND MORE
CHALLENGING FORECAST TAKES HOLD BY MID NEXT WEEK.
A TRANSITIONING WEST/NORTHWEST UPPER LEVEL FLOW WILL KEEP THE
REGION MAINLY DRY AND MILD THROUGH THROUGH THE REMAINDER OF THE
HOLIDAY WEEKEND. REGIONAL TRAVEL CONCERNS WILL BE NIL...AND BOTH
DAYTIME HIGHS AND NIGHTTIME LOWS WILL BE AT OR SLIGHTLY ABOVE
SEASONAL NORMALS. ONE NOTABLE WEATHER ELEMENT WILL THE WIND...OR
LACK THERE OF ON SATURDAY AND SUNDAY. THAT WILL HELP OFFSET ANY
COOLING FROM PASSING CLOUDS THROUGHOUT THE WEEKEND.
OVERALL...PRETTY NICE FOR THE END OF NOVEMBER. WARM ADVECTION
ASSOCIATED WITH WAVE ACROSS THE NORTHERN PLAINS SUNDAY WILL
THICKEN CLOUDS...BUT NOT TOO EXCITED ABOUT INCURRING ANY
MEASURABLE PRECIPITATION AT THIS POINT.
ACTUALLY THE MILD WEATHER WILL CONTINUE INTO THE FIRST PART OF
NEXT WEEK...ALTHOUGH THINGS WILL BE CHANGING AS UPPER LEVEL
HEIGHTS LOWER AND WE START TO SEE UPPER LEVEL LOW PRESSURE DEEPEN
IN THE GREAT BASIN REGION. AS THE LOW STRENGTHENS...AN INCREASING
SOUTH TO SOUTHEAST FLOW ACROSS THE CENTRAL/SOUTHERN PLAINS
DEVELOPS WHICH WILL KEEP TEMPERATURES ON THE MILD SIDE
MONDAY/TUESDAY. THERE IS SOME MODEL LIKENESS IN OVERALL
TRENDS...BUT VERY UNEASY IN TRYING TO PIN DOWN ANY SPECIFIC
DETAILS FOR NEXT WEEKS FORECAST AT THIS POINT. WE HAVE BEEN
ANTICIPATING A COLD AIR PUSH NEXT WEEK...AND THAT STILL LOOKS ON
TRACK FOR ABOUT WEDNESDAY...BUT THE COLD AIR PLUNGE COMES IN
PIECES WITH THE COLDEST AIR NOT LIKELY TO MAKE IT INTO THE AREA
UNTIL LATER NEXT WEEK. MODELS SUGGEST HEAVIEST PRECIPITATION
TRENDS WILL LIKELY BE ACROSS THE DAKOTAS AT THIS POINT...WITH ONLY
SMALL CHANCES FOR RAIN OR RAIN/SNOW MIX IN THE FORECAST AT THIS
POINT AS THE SYSTEM APPROACHES.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z FRIDAY AFTERNOON)
ISSUED AT 1140 AM CST THU NOV 28 2013
A BREAK IN MVFR STRATUS IS EVIDENT ON LATEST SATELLITE
IMAGERY...BUT EXPECT THIS STRATUS TO RAPIDLY FILL BACK IN BY ABOUT
28/20Z...AND PERSIST THROUGH THE LATE AFTERNOON OR EARLY EVENING
HOURS. WINDS WILL GENERALLY REMAIN NORTHERLY THROUGH THE AFTERNOON
HOURS...EVENTUALLY BECOMING LIGHT AND VARIABLE AS THE SURFACE HIGH
TRACKS SOUTH ACROSS THE MISSOURI RIVER VALLEY. SOUTHERLY WINDS ARE
EXPECTED TO INCREASE IN RETURN FLOW AROUND THIS HIGH PRESSURE
SYSTEM ON FRIDAY.
&&
.GID WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
KS...NONE.
&&
$$
UPDATE...ROSSI
SHORT TERM...NOAA/NWS/BRYANT
LONG TERM...NOAA/NWS/MORITZ
AVIATION...ROSSI
AREA FORECAST DISCUSSION
NWS HASTINGS NE
919 AM CST THU NOV 28 2013
.UPDATE...
ISSUED AT 913 AM CST THU NOV 28 2013
WITH THICK STRATUS EVIDENT ON SATELLITE IMAGERY AND LATEST RAP
COMING IN WITH PESSIMISTIC CONDITIONS FOR THE REST OF THE
DAY...WENT AHEAD AND FURTHER INCREASED CLOUD COVER FROM PREVIOUS
UPDATE AS WELL AS DROPPED FORECAST HIGH TEMPERATURES ABOUT 5
DEGREES ACROSS THE BOARD. OTHERWISE...NO ADDITIONAL CHANGES
NECESSARY AT THIS TIME.
UPDATE ISSUED AT 749 AM CST THU NOV 28 2013
BASED ON LATEST SHORTWAVE IR SATELLITE AND MODEL TRENDS...
ANTICIPATE WE WILL NEED TO MAKE SOME SUBSTANTIAL CHANGES TO THE
FCST TODAY AND POSSIBLY INTO TONIGHT AND TOMORROW. THESE CHANGES
WILL INVOLVE MORE CLOUDS AND COOLER TEMPS...PROBABLY NOT BECOMING
AS WARM AS THOUGHT THE LAST FEW DAYS AND WE SAW THIS AS A
POTENTIAL OPTION EARLIER THIS WEEK. IT/S TOUGH TO FCST FAR IN
ADVANCE THOUGH.
THERE IS AN EXTENSIVE BANK OF STRATUS RACING S TO THE KS-NEB
BORDER AT THIS TIME AND IT EXTENDS ALL THE WAY UP INTO THE
CANADIAN PRAIRIES. BELIEVE THIS IS GOING TO BE A FCST PROBLEM THRU
SUNSET TOMORROW AS IT WILL BE STUCK IN A THERMAL TROF /COLD
POCKET/ AND WILL RESIST EROSION. WE REALLY NEED WARM AIR ADVECTION
TO GET RID OF IT AND THAT WILL NOT HAPPEN UNTIL LATE TONIGHT OR
TOMORROW.
SO THE FCST SKY HAS BEEN TURNED SIGNIFICANTLY MORE PESSIMISTIC
THRU MIDDAY AND EXPECT WE WILL NEED TO PUSH THIS FURTHER INTO THE
AFTERNOON PENDING THE LATEST SATELLITE TRENDS.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 332 AM CST THU NOV 28 2013
OVERNIGHT UPPER AIR ANALYSIS INDICATES MID TO UPPER LEVEL
TROUGHING OVER THE EASTERN CONUS...WITH A RIDGE OVER THE WEST AND
A MID LEVEL LOW OVER THE PACIFIC OFF THE CALIFORNIA COAST. A
SUBTLE MID LEVEL PERTURBATION IS ALSO NOTED OVER SOUTHERN
MINNESOTA...MOVING SOUTHEAST. MID TO UPPER LEVEL JET ENERGY
EXTENDS FROM SOUTH CENTRAL CANADA...SOUTHEAST INTO THE CENTRAL
CONUS...AND FINALLY EAST AND NORTHEAST ALONG THE EASTERN CONUS
INTO SOUTHEASTERN CANADA. MID TO UPPER LEVEL FLOW OVER OUR AREA
MAXES OUT AT AROUND 70KTS BETWEEN 300MB AND 200MB PER 00Z SOUNDING
DATA FROM KLBF AND KOAX. WATER VAPOR IMAGERY INDICATES INCREASED
VALUES OF MID LEVEL MOISTURE EXTENDING ALONG THE BACK SIDE OF THE
WEST COAST RIDGE...AS WELL AS FROM THE PACIFIC EASTWARD INTO
MEXICO AND THE SOUTHERN PLAINS. MID LEVEL MOISTURE OVER OUR AREA
HOWEVER REMAINS FAIRLY LIMITED. AT THE SURFACE...AN AREA OF LOW
BAROMETRIC PRESSURE EXISTS OVER NORTHWEST IOWA JUST AHEAD OF THE
AFOREMENTIONED MID LEVEL PERTURBATION...WITH AN ASSOCIATED COLD
FRONT EXTENDING FROM WESTERN IOWA INTO SOUTHEASTERN NEBRASKA AND
NORTHERN KANSAS. THIS FRONT HAS CLEARED MOST ALL OF OUR CWA AND AS
A RESULT...THE LOW LEVEL WIND FIELD ACROSS OUR AREA REMAINS FROM
THE NORTH/NORTHWEST.
GUIDANCE FROM THE NAM...OPERATIONAL GFS...EC AND SREF-MEAN ALL
SUGGEST NORTHWESTERLY MID TO UPPER LEVEL FLOW WILL PERSIST OVER
OUR AREA THROUGH THE NEXT 24 HOURS AS THE EASTERN CONUS TROUGH AND
WESTERN CONUS RIDGE BOTH TREK EAST. THE MID LEVEL
PERTURBATION...CURRENTLY OVER SOUTHERN MINNESOTA...IS EXPECTED TO
CONTINUE MOVING SOUTHEAST THROUGH THE NEXT 24 HOURS...WITH NO
OTHER MID LEVEL SHORTWAVES/PERTURBATIONS EXPECTED TO IMPACT THE
REGION. AT THE SURFACE...THE AREA OF LOW BAROMETRIC
PRESSURE...CURRENTLY OVER NORTHWEST IOWA...SHOULD ALSO CONTINUE
MOVING TO THE EAST/SOUTHEAST THROUGH THE NEXT 24 HOURS...WITH THE
ASSOCIATED LOW LEVEL BAROCLINIC ZONE PUSHING FARTHER
SOUTH/SOUTHEAST ACROSS THE PLAINS. THE LOW LEVEL WIND FIELD ACROSS
OUR AREA SHOULD REMAIN FROM THE NORTH/NORTHWEST THROUGH MUCH OF
TODAY AS A RESULT. THAT BEING SAID...GUIDANCE SUGGESTS THE PASSAGE
OF A SURFACE RIDGE TO EAST SHOULD ALLOW FOR LOW LEVEL RETURN FLOW
ACROSS OUR AREA DURING THE OVERNIGHT HOURS TONIGHT.
WITH AN OVERALL LACK IN OMEGA EXPECTED OVER OUR AREA...DRY
CONDITIONS ARE CURRENTLY FORECAST THROUGH THE NEXT 24 HOURS.
SATELLITE IMAGERY INDICATES A BAND OF STRATUS OVER MUCH OF THE
NORTHERN PLAINS THIS MORNING AND THIS STRATUS IS ADVANCING TO THE
SOUTH...ABOUT 150 MILES NORTH OF THE AFOREMENTIONED SURFACE FRONT.
GUIDANCE FROM THE NAM AND RAP BOTH SHOW THIS STRATUS...WITH HIGH
RELATIVE HUMIDITY VALUES AT 925MB NOTED ON PLAN VIEW
MAPS...INFILTRATING OUR NORTH/NORTHEASTERN CWA JUST PRIOR TO
SUNRISE THIS MORNING...BUT DISSIPATING POST-SUNRISE AS DIABATIC
HEATING RESULTS IN INCREASED BOUNDARY LAYER HEIGHT AND MIXING.
WENT AHEAD AND PLAYED PRETTY CLOSE TO NAM AND RAP GUIDANCE FOR THE
CLOUD FORECAST THROUGH THE FIRST PART OF THE SHORT TERM FORECAST
PERIOD...WITH THIS STRATUS EXPECTED TO IMPACT OUR NORTH/NORTHEAST
BY 10Z OR 11Z THIS MORNING...AND THEN DISSIPATE BY 15Z OR 16Z.
WITH LOW LEVEL RETURN FLOW INFILTRATING THE REGION TONIGHT...THERE
ARE INDICATIONS OF ISENTROPIC UPGLIDE AND SATURATION...PRIMARILY
ALONG THE 275-285K SURFACES...OVER THE HIGH PLAINS OF KANSAS AND
NEBRASKA. ALTHOUGH IT APPEARS MUCH OF OUR CWA SHOULD BE SPARED
FROM ANY STRATUS DEVELOPMENT THROUGH 12Z FRIDAY...925MB RELATIVE
HUMIDITY PLAN VIEW MAPS FROM THE NAM...OPERATIONAL GFS AND EC ALL
SUGGEST OUR EXTREME WEST/SOUTHWEST COULD ACTUALLY OBSERVE QUITE A
BIT OF CLOUD COVER TOWARDS SUNRISE FRIDAY AS THE EASTERN PERIPHERY
OF THE HIGH PLAINS STRATUS CLIPS THE AREA. WENT AHEAD WITH A
BROKEN CEILING ACROSS OUR EXTREME WEST/SOUTHWEST BY 12Z FRIDAY AS
A RESULT.
THE INTRUSION OF A COOLER LOW LEVEL AIRMASS BEHIND THE LOW LEVEL
BAROCLINIC ZONE SHOULD RESULT IN A COOLER DAY TODAY WHEN COMPARED
TO WEDNESDAY. HIGH TEMPERATURES GENERALLY IN THE MID 30S ACROSS
OUR NORTH...AND INTO THE MID 40S ACROSS OUR SOUTH...ARE FORECAST
FOR TODAY AS A RESULT. IT MIGHT OTHERWISE BE REASONABLE TO THINK
TONIGHT WILL BE COOLER WHEN COMPARED TO EARLY THIS MORNING...BUT
WITH LOW LEVEL RETURN FLOW EXPECTED TO INFILTRATE OUR AREA DURING
THE OVERNIGHT HOURS...OVERNIGHT LOWS TONIGHT SHOULD ACTUALLY BE
PRETTY CLOSE TO WHAT WE ARE EXPECTING EARLY THIS MORNING.
.LONG TERM...(FRIDAY THROUGH WEDNESDAY)
ISSUED AT 332 AM CST THU NOV 28 2013
THE FIRST PART OF THE LONG TERM FORECAST IS DRY WITH ABOVE NORMAL
TEMPERATURES...AFTERWHICH A MORE UNSETTLED...COLDER AND MORE
CHALLENGING FORECAST TAKES HOLD BY MID NEXT WEEK.
A TRANSITIONING WEST/NORTHWEST UPPER LEVEL FLOW WILL KEEP THE
REGION MAINLY DRY AND MILD THROUGH THROUGH THE REMAINDER OF THE
HOLIDAY WEEKEND. REGIONAL TRAVEL CONCERNS WILL BE NIL...AND BOTH
DAYTIME HIGHS AND NIGHTTIME LOWS WILL BE AT OR SLIGHTLY ABOVE
SEASONAL NORMALS. ONE NOTABLE WEATHER ELEMENT WILL THE WIND...OR
LACK THERE OF ON SATURDAY AND SUNDAY. THAT WILL HELP OFFSET ANY
COOLING FROM PASSING CLOUDS THROUGHOUT THE WEEKEND.
OVERALL...PRETTY NICE FOR THE END OF NOVEMBER. WARM ADVECTION
ASSOCIATED WITH WAVE ACROSS THE NORTHERN PLAINS SUNDAY WILL
THICKEN CLOUDS...BUT NOT TOO EXCITED ABOUT INCURRING ANY
MEASURABLE PRECIPITATION AT THIS POINT.
ACTUALLY THE MILD WEATHER WILL CONTINUE INTO THE FIRST PART OF
NEXT WEEK...ALTHOUGH THINGS WILL BE CHANGING AS UPPER LEVEL
HEIGHTS LOWER AND WE START TO SEE UPPER LEVEL LOW PRESSURE DEEPEN
IN THE GREAT BASIN REGION. AS THE LOW STRENGTHENS...AN INCREASING
SOUTH TO SOUTHEAST FLOW ACROSS THE CENTRAL/SOUTHERN PLAINS
DEVELOPS WHICH WILL KEEP TEMPERATURES ON THE MILD SIDE
MONDAY/TUESDAY. THERE IS SOME MODEL LIKENESS IN OVERALL
TRENDS...BUT VERY UNEASY IN TRYING TO PIN DOWN ANY SPECIFIC
DETAILS FOR NEXT WEEKS FORECAST AT THIS POINT. WE HAVE BEEN
ANTICIPATING A COLD AIR PUSH NEXT WEEK...AND THAT STILL LOOKS ON
TRACK FOR ABOUT WEDNESDAY...BUT THE COLD AIR PLUNGE COMES IN
PIECES WITH THE COLDEST AIR NOT LIKELY TO MAKE IT INTO THE AREA
UNTIL LATER NEXT WEEK. MODELS SUGGEST HEAVIEST PRECIPITATION
TRENDS WILL LIKELY BE ACROSS THE DAKOTAS AT THIS POINT...WITH ONLY
SMALL CHANCES FOR RAIN OR RAIN/SNOW MIX IN THE FORECAST AT THIS
POINT AS THE SYSTEM APPROACHES.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z FRIDAY MORNING)
ISSUED AT 530 AM CST THU NOV 28 2013
MVFR CONDITIONS EXPECTED TO START THE TAF PERIOD...WITH VFR
CONDITIONS EXPECTED 15Z AND BEYOND.
AN AREA OF STRATUS HAS BEEN MOVING SOUTH FROM SOUTH DAKOTA ALL
NIGHT AND IS NOW MOVING INTO THE GRI AREA. THE CEILING WITHIN THIS
STRATUS GENERALLY RANGES BETWEEN 1000FT AND 1500FT AGL...THUS THE
MVFR FORECAST 12-15Z. GUIDANCE CONTINUES TO SUGGEST THIS STRATUS
WILL LIFT AND BREAK APART AFTER SUNRISE AS INCREASING DIABATIC
HEATING ALLOWS FOR INCREASING BOUNDARY LAYER DEPTH AND MIXING. VFR
CONDITIONS ARE CURRENTLY EXPECTED TO BE RESTORED BY 15Z...BUT THIS
WILL NEED TO BE MONITORED THROUGH THE NEXT FEW HOURS FOR POSSIBLE
UPDATES TO THE TAF. THE SURFACE WIND WILL REMAIN FROM THE
NORTH/NORTHEAST TODAY...SUSTAINED AT AROUND 10KTS. THE PASSAGE OF
A SURFACE RIDGE WILL THEN ALLOW FOR A WEAK...NO GREATER THAN
6KTS...SOUTHEASTERLY LOW LEVEL WIND FIELD OVERNIGHT TONIGHT.
VISIBILITY RESTRICTION IS NOT EXPECTED AT GRI THROUGH THE NEXT 24
HOURS.
&&
.GID WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
KS...NONE.
&&
$$
UPDATE...ROSSI
SHORT TERM...NOAA/NWS/BRYANT
LONG TERM...NOAA/NWS/MORITZ
AVIATION...NOAA/NWS/BRYANT
AREA FORECAST DISCUSSION
NWS HASTINGS NE
749 AM CST THU NOV 28 2013
.UPDATE...
ISSUED AT 749 AM CST THU NOV 28 2013
BASED ON LATEST SHORTWAVE IR SATELLITE AND MODEL TRENDS...
ANTICIPATE WE WILL NEED TO MAKE SOME SUBSTANTIAL CHANGES TO THE
FCST TODAY AND POSSIBLY INTO TONIGHT AND TOMORROW. THESE CHANGES
WILL INVOLVE MORE CLOUDS AND COOLER TEMPS...PROBABLY NOT BECOMING
AS WARM AS THOUGHT THE LAST FEW DAYS AND WE SAW THIS AS A
POTENTIAL OPTION EARLIER THIS WEEK. IT/S TOUGH TO FCST FAR IN
ADVANCE THOUGH.
THERE IS AN EXTENSIVE BANK OF STRATUS RACING S TO THE KS-NEB
BORDER AT THIS TIME AND IT EXTENDS ALL THE WAY UP INTO THE
CANADIAN PRAIRIES. BELIEVE THIS IS GOING TO BE A FCST PROBLEM THRU
SUNSET TOMORROW AS IT WILL BE STUCK IN A THERMAL TROF /COLD
POCKET/ AND WILL RESIST EROSION. WE REALLY NEED WARM AIR ADVECTION
TO GET RID OF IT AND THAT WILL NOT HAPPEN UNTIL LATE TONIGHT OR
TOMORROW.
SO THE FCST SKY HAS BEEN TURNED SIGNIFICANTLY MORE PESSIMISTIC
THRU MIDDAY AND EXPECT WE WILL NEED TO PUSH THIS FURTHER INTO THE
AFTERNOON PENDING THE LATEST SATELLITE TRENDS.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 332 AM CST THU NOV 28 2013
OVERNIGHT UPPER AIR ANALYSIS INDICATES MID TO UPPER LEVEL
TROUGHING OVER THE EASTERN CONUS...WITH A RIDGE OVER THE WEST AND
A MID LEVEL LOW OVER THE PACIFIC OFF THE CALIFORNIA COAST. A
SUBTLE MID LEVEL PERTURBATION IS ALSO NOTED OVER SOUTHERN
MINNESOTA...MOVING SOUTHEAST. MID TO UPPER LEVEL JET ENERGY
EXTENDS FROM SOUTH CENTRAL CANADA...SOUTHEAST INTO THE CENTRAL
CONUS...AND FINALLY EAST AND NORTHEAST ALONG THE EASTERN CONUS
INTO SOUTHEASTERN CANADA. MID TO UPPER LEVEL FLOW OVER OUR AREA
MAXES OUT AT AROUND 70KTS BETWEEN 300MB AND 200MB PER 00Z SOUNDING
DATA FROM KLBF AND KOAX. WATER VAPOR IMAGERY INDICATES INCREASED
VALUES OF MID LEVEL MOISTURE EXTENDING ALONG THE BACK SIDE OF THE
WEST COAST RIDGE...AS WELL AS FROM THE PACIFIC EASTWARD INTO
MEXICO AND THE SOUTHERN PLAINS. MID LEVEL MOISTURE OVER OUR AREA
HOWEVER REMAINS FAIRLY LIMITED. AT THE SURFACE...AN AREA OF LOW
BAROMETRIC PRESSURE EXISTS OVER NORTHWEST IOWA JUST AHEAD OF THE
AFOREMENTIONED MID LEVEL PERTURBATION...WITH AN ASSOCIATED COLD
FRONT EXTENDING FROM WESTERN IOWA INTO SOUTHEASTERN NEBRASKA AND
NORTHERN KANSAS. THIS FRONT HAS CLEARED MOST ALL OF OUR CWA AND AS
A RESULT...THE LOW LEVEL WIND FIELD ACROSS OUR AREA REMAINS FROM
THE NORTH/NORTHWEST.
GUIDANCE FROM THE NAM...OPERATIONAL GFS...EC AND SREF-MEAN ALL
SUGGEST NORTHWESTERLY MID TO UPPER LEVEL FLOW WILL PERSIST OVER
OUR AREA THROUGH THE NEXT 24 HOURS AS THE EASTERN CONUS TROUGH AND
WESTERN CONUS RIDGE BOTH TREK EAST. THE MID LEVEL
PERTURBATION...CURRENTLY OVER SOUTHERN MINNESOTA...IS EXPECTED TO
CONTINUE MOVING SOUTHEAST THROUGH THE NEXT 24 HOURS...WITH NO
OTHER MID LEVEL SHORTWAVES/PERTURBATIONS EXPECTED TO IMPACT THE
REGION. AT THE SURFACE...THE AREA OF LOW BAROMETRIC
PRESSURE...CURRENTLY OVER NORTHWEST IOWA...SHOULD ALSO CONTINUE
MOVING TO THE EAST/SOUTHEAST THROUGH THE NEXT 24 HOURS...WITH THE
ASSOCIATED LOW LEVEL BAROCLINIC ZONE PUSHING FARTHER
SOUTH/SOUTHEAST ACROSS THE PLAINS. THE LOW LEVEL WIND FIELD ACROSS
OUR AREA SHOULD REMAIN FROM THE NORTH/NORTHWEST THROUGH MUCH OF
TODAY AS A RESULT. THAT BEING SAID...GUIDANCE SUGGESTS THE PASSAGE
OF A SURFACE RIDGE TO EAST SHOULD ALLOW FOR LOW LEVEL RETURN FLOW
ACROSS OUR AREA DURING THE OVERNIGHT HOURS TONIGHT.
WITH AN OVERALL LACK IN OMEGA EXPECTED OVER OUR AREA...DRY
CONDITIONS ARE CURRENTLY FORECAST THROUGH THE NEXT 24 HOURS.
SATELLITE IMAGERY INDICATES A BAND OF STRATUS OVER MUCH OF THE
NORTHERN PLAINS THIS MORNING AND THIS STRATUS IS ADVANCING TO THE
SOUTH...ABOUT 150 MILES NORTH OF THE AFOREMENTIONED SURFACE FRONT.
GUIDANCE FROM THE NAM AND RAP BOTH SHOW THIS STRATUS...WITH HIGH
RELATIVE HUMIDITY VALUES AT 925MB NOTED ON PLAN VIEW
MAPS...INFILTRATING OUR NORTH/NORTHEASTERN CWA JUST PRIOR TO
SUNRISE THIS MORNING...BUT DISSIPATING POST-SUNRISE AS DIABATIC
HEATING RESULTS IN INCREASED BOUNDARY LAYER HEIGHT AND MIXING.
WENT AHEAD AND PLAYED PRETTY CLOSE TO NAM AND RAP GUIDANCE FOR THE
CLOUD FORECAST THROUGH THE FIRST PART OF THE SHORT TERM FORECAST
PERIOD...WITH THIS STRATUS EXPECTED TO IMPACT OUR NORTH/NORTHEAST
BY 10Z OR 11Z THIS MORNING...AND THEN DISSIPATE BY 15Z OR 16Z.
WITH LOW LEVEL RETURN FLOW INFILTRATING THE REGION TONIGHT...THERE
ARE INDICATIONS OF ISENTROPIC UPGLIDE AND SATURATION...PRIMARILY
ALONG THE 275-285K SURFACES...OVER THE HIGH PLAINS OF KANSAS AND
NEBRASKA. ALTHOUGH IT APPEARS MUCH OF OUR CWA SHOULD BE SPARED
FROM ANY STRATUS DEVELOPMENT THROUGH 12Z FRIDAY...925MB RELATIVE
HUMIDITY PLAN VIEW MAPS FROM THE NAM...OPERATIONAL GFS AND EC ALL
SUGGEST OUR EXTREME WEST/SOUTHWEST COULD ACTUALLY OBSERVE QUITE A
BIT OF CLOUD COVER TOWARDS SUNRISE FRIDAY AS THE EASTERN PERIPHERY
OF THE HIGH PLAINS STRATUS CLIPS THE AREA. WENT AHEAD WITH A
BROKEN CEILING ACROSS OUR EXTREME WEST/SOUTHWEST BY 12Z FRIDAY AS
A RESULT.
THE INTRUSION OF A COOLER LOW LEVEL AIRMASS BEHIND THE LOW LEVEL
BAROCLINIC ZONE SHOULD RESULT IN A COOLER DAY TODAY WHEN COMPARED
TO WEDNESDAY. HIGH TEMPERATURES GENERALLY IN THE MID 30S ACROSS
OUR NORTH...AND INTO THE MID 40S ACROSS OUR SOUTH...ARE FORECAST
FOR TODAY AS A RESULT. IT MIGHT OTHERWISE BE REASONABLE TO THINK
TONIGHT WILL BE COOLER WHEN COMPARED TO EARLY THIS MORNING...BUT
WITH LOW LEVEL RETURN FLOW EXPECTED TO INFILTRATE OUR AREA DURING
THE OVERNIGHT HOURS...OVERNIGHT LOWS TONIGHT SHOULD ACTUALLY BE
PRETTY CLOSE TO WHAT WE ARE EXPECTING EARLY THIS MORNING.
.LONG TERM...(FRIDAY THROUGH WEDNESDAY)
ISSUED AT 332 AM CST THU NOV 28 2013
THE FIRST PART OF THE LONG TERM FORECAST IS DRY WITH ABOVE NORMAL
TEMPERATURES...AFTERWHICH A MORE UNSETTLED...COLDER AND MORE
CHALLENGING FORECAST TAKES HOLD BY MID NEXT WEEK.
A TRANSITIONING WEST/NORTHWEST UPPER LEVEL FLOW WILL KEEP THE
REGION MAINLY DRY AND MILD THROUGH THROUGH THE REMAINDER OF THE
HOLIDAY WEEKEND. REGIONAL TRAVEL CONCERNS WILL BE NIL...AND BOTH
DAYTIME HIGHS AND NIGHTTIME LOWS WILL BE AT OR SLIGHTLY ABOVE
SEASONAL NORMALS. ONE NOTABLE WEATHER ELEMENT WILL THE WIND...OR
LACK THERE OF ON SATURDAY AND SUNDAY. THAT WILL HELP OFFSET ANY
COOLING FROM PASSING CLOUDS THROUGHOUT THE WEEKEND.
OVERALL...PRETTY NICE FOR THE END OF NOVEMBER. WARM ADVECTION
ASSOCIATED WITH WAVE ACROSS THE NORTHERN PLAINS SUNDAY WILL
THICKEN CLOUDS...BUT NOT TOO EXCITED ABOUT INCURRING ANY
MEASURABLE PRECIPITATION AT THIS POINT.
ACTUALLY THE MILD WEATHER WILL CONTINUE INTO THE FIRST PART OF
NEXT WEEK...ALTHOUGH THINGS WILL BE CHANGING AS UPPER LEVEL
HEIGHTS LOWER AND WE START TO SEE UPPER LEVEL LOW PRESSURE DEEPEN
IN THE GREAT BASIN REGION. AS THE LOW STRENGTHENS...AN INCREASING
SOUTH TO SOUTHEAST FLOW ACROSS THE CENTRAL/SOUTHERN PLAINS
DEVELOPS WHICH WILL KEEP TEMPERATURES ON THE MILD SIDE
MONDAY/TUESDAY. THERE IS SOME MODEL LIKENESS IN OVERALL
TRENDS...BUT VERY UNEASY IN TRYING TO PIN DOWN ANY SPECIFIC
DETAILS FOR NEXT WEEKS FORECAST AT THIS POINT. WE HAVE BEEN
ANTICIPATING A COLD AIR PUSH NEXT WEEK...AND THAT STILL LOOKS ON
TRACK FOR ABOUT WEDNESDAY...BUT THE COLD AIR PLUNGE COMES IN
PIECES WITH THE COLDEST AIR NOT LIKELY TO MAKE IT INTO THE AREA
UNTIL LATER NEXT WEEK. MODELS SUGGEST HEAVIEST PRECIPITATION
TRENDS WILL LIKELY BE ACROSS THE DAKOTAS AT THIS POINT...WITH ONLY
SMALL CHANCES FOR RAIN OR RAIN/SNOW MIX IN THE FORECAST AT THIS
POINT AS THE SYSTEM APPROACHES.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z FRIDAY MORNING)
ISSUED AT 530 AM CST THU NOV 28 2013
MVFR CONDITIONS EXPECTED TO START THE TAF PERIOD...WITH VFR
CONDITIONS EXPECTED 15Z AND BEYOND.
AN AREA OF STRATUS HAS BEEN MOVING SOUTH FROM SOUTH DAKOTA ALL
NIGHT AND IS NOW MOVING INTO THE GRI AREA. THE CEILING WITHIN THIS
STRATUS GENERALLY RANGES BETWEEN 1000FT AND 1500FT AGL...THUS THE
MVFR FORECAST 12-15Z. GUIDANCE CONTINUES TO SUGGEST THIS STRATUS
WILL LIFT AND BREAK APART AFTER SUNRISE AS INCREASING DIABATIC
HEATING ALLOWS FOR INCREASING BOUNDARY LAYER DEPTH AND MIXING. VFR
CONDITIONS ARE CURRENTLY EXPECTED TO BE RESTORED BY 15Z...BUT THIS
WILL NEED TO BE MONITORED THROUGH THE NEXT FEW HOURS FOR POSSIBLE
UPDATES TO THE TAF. THE SURFACE WIND WILL REMAIN FROM THE
NORTH/NORTHEAST TODAY...SUSTAINED AT AROUND 10KTS. THE PASSAGE OF
A SURFACE RIDGE WILL THEN ALLOW FOR A WEAK...NO GREATER THAN
6KTS...SOUTHEASTERLY LOW LEVEL WIND FIELD OVERNIGHT TONIGHT.
VISIBILITY RESTRICTION IS NOT EXPECTED AT GRI THROUGH THE NEXT 24
HOURS.
&&
.GID WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
KS...NONE.
&&
$$
UPDATE...HALBLAUB
SHORT TERM...NOAA/NWS/BRYANT
LONG TERM...NOAA/NWS/MORITZ
AVIATION...NOAA/NWS/BRYANT
AREA FORECAST DISCUSSION
NWS OMAHA/VALLEY NE
548 AM CST THU NOV 28 2013
.AVIATION...
12Z TAFS FOR KOMA...KOFK...KLNK
THE MAIN INITIAL ISSUE IS THE MVFR STRATUS DECK THAT HAS MOVED
INTO KOFK AND IS APPROACHING KOMA/KLNK. THE MODELS ARE NOT
HANDLING THIS DECK WELL WITH THE RUC13 LIKELY DOING THE BEST.
LATEST SAT IMAGERY INDICATES THE CLOUDS EWD PROGRESS HAS SLOWED
AND THIS IS INDICATED IN MOST MODELS THROUGH THE MORNING. THUS WE
WILL LEAVE THE DECK OUT OF KOMA FOR NOW...AND ALTHOUGH THE SWD
MOVEMENT HAS ALSO SLOWED WE WILL INCLUDE A TEMPO MVFR GROUP THIS
MORNING FOR A TIME AS THE CLOUDS ARE MORE LIKELY TO MAKE IT THERE
GIVEN THE 925 MB WINDS. OTHERWISE THE MVFR CLOUDS WILL SLOWLY
DISSIPATE THIS AFTERNOON AT KOFK...AND ONCE THIS OCCURS VFR
CONDITIONS ARE EXPECTED FOR THE REST OF THE PERIOD AT ALL SITES.
WINDS WILL START TO DIMINISH THIS AFTN AND WILL GO LIGHT
OVERNIGHT.
BOUSTEAD
&&
.PREV DISCUSSION... /ISSUED 329 AM CST THU NOV 28 2013/
DISCUSSION...
WATER VAPOR IMAGERY THIS MORNING SHOWING A DISTINCT CLOSED LOW
SPINNING JUST OFF THE WEST COAST ALONG WITH A WELL AMPLIFIED RIDGE
OVER THE WRN CONUS EXTENDING ALL THE WAY UP THE CANADIAN WEST COAST.
MEANWHILE BROAD DOWNSTREAM TROF WAS SITUATED OVER THE ERN CONUS.
HAVE OPTED TO MAKE SOME POP CHANGES IN THE EXTENDED PDS...IN
PARTICULAR MON THRU WED BASED ON 00Z ECM TRENDING TWD DRIER GFS
SOLUTION.
FIRST THOUGH...ANTICIPATED MODERATE WARMING TREND THRU EARLY NEXT
APPEARS TO BE ON TRACK. ALL THIS IN PART TO LARGE SCALE FLOW
TRANSITIONING TO SWLY WITH GRADUAL HGT RISES SPREADING OVER THE
CNTRL PLAINS. AND AT THIS POINT...MET/MEX/ECE MOS PROJECTING HIGHS
IN THE LOW/MID 40S LOOK PRETTY REASONABLE.
AS FOR PCPN CHANCES NEXT WEEK...WITH THE ECM/GFS IN SOMEWHAT BETTER
AGREEMENT...FEEL COMPELLED TO GO DRY ON MONDAY AS WELL AS TRIM POPS
BACK TO SLGT TUESDAY THRU THURSDAY. BOTH GENERALLY PLACE BRUNT OF
QPF FIELD NORTH OF THE CWA...WHICH THE CMC LENDS SOME CREDENCE TO.
BUFKIT/CRITICAL THNKS PROGS GENERALLY SUPPORT RA WITH POSSIBLE
RA/SN MIX DURING THE OVERNIGHT HOURS.
DEE
&&
.OAX WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
IA...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS HASTINGS NE
530 AM CST THU NOV 28 2013
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 332 AM CST THU NOV 28 2013
OVERNIGHT UPPER AIR ANALYSIS INDICATES MID TO UPPER LEVEL
TROUGHING OVER THE EASTERN CONUS...WITH A RIDGE OVER THE WEST AND
A MID LEVEL LOW OVER THE PACIFIC OFF THE CALIFORNIA COAST. A
SUBTLE MID LEVEL PERTURBATION IS ALSO NOTED OVER SOUTHERN
MINNESOTA...MOVING SOUTHEAST. MID TO UPPER LEVEL JET ENERGY
EXTENDS FROM SOUTH CENTRAL CANADA...SOUTHEAST INTO THE CENTRAL
CONUS...AND FINALLY EAST AND NORTHEAST ALONG THE EASTERN CONUS
INTO SOUTHEASTERN CANADA. MID TO UPPER LEVEL FLOW OVER OUR AREA
MAXES OUT AT AROUND 70KTS BETWEEN 300MB AND 200MB PER 00Z SOUNDING
DATA FROM KLBF AND KOAX. WATER VAPOR IMAGERY INDICATES INCREASED
VALUES OF MID LEVEL MOISTURE EXTENDING ALONG THE BACK SIDE OF THE
WEST COAST RIDGE...AS WELL AS FROM THE PACIFIC EASTWARD INTO
MEXICO AND THE SOUTHERN PLAINS. MID LEVEL MOISTURE OVER OUR AREA
HOWEVER REMAINS FAIRLY LIMITED. AT THE SURFACE...AN AREA OF LOW
BAROMETRIC PRESSURE EXISTS OVER NORTHWEST IOWA JUST AHEAD OF THE
AFOREMENTIONED MID LEVEL PERTURBATION...WITH AN ASSOCIATED COLD
FRONT EXTENDING FROM WESTERN IOWA INTO SOUTHEASTERN NEBRASKA AND
NORTHERN KANSAS. THIS FRONT HAS CLEARED MOST ALL OF OUR CWA AND AS
A RESULT...THE LOW LEVEL WIND FIELD ACROSS OUR AREA REMAINS FROM
THE NORTH/NORTHWEST.
GUIDANCE FROM THE NAM...OPERATIONAL GFS...EC AND SREF-MEAN ALL
SUGGEST NORTHWESTERLY MID TO UPPER LEVEL FLOW WILL PERSIST OVER
OUR AREA THROUGH THE NEXT 24 HOURS AS THE EASTERN CONUS TROUGH AND
WESTERN CONUS RIDGE BOTH TREK EAST. THE MID LEVEL
PERTURBATION...CURRENTLY OVER SOUTHERN MINNESOTA...IS EXPECTED TO
CONTINUE MOVING SOUTHEAST THROUGH THE NEXT 24 HOURS...WITH NO
OTHER MID LEVEL SHORTWAVES/PERTURBATIONS EXPECTED TO IMPACT THE
REGION. AT THE SURFACE...THE AREA OF LOW BAROMETRIC
PRESSURE...CURRENTLY OVER NORTHWEST IOWA...SHOULD ALSO CONTINUE
MOVING TO THE EAST/SOUTHEAST THROUGH THE NEXT 24 HOURS...WITH THE
ASSOCIATED LOW LEVEL BAROCLINIC ZONE PUSHING FARTHER
SOUTH/SOUTHEAST ACROSS THE PLAINS. THE LOW LEVEL WIND FIELD ACROSS
OUR AREA SHOULD REMAIN FROM THE NORTH/NORTHWEST THROUGH MUCH OF
TODAY AS A RESULT. THAT BEING SAID...GUIDANCE SUGGESTS THE PASSAGE
OF A SURFACE RIDGE TO EAST SHOULD ALLOW FOR LOW LEVEL RETURN FLOW
ACROSS OUR AREA DURING THE OVERNIGHT HOURS TONIGHT.
WITH AN OVERALL LACK IN OMEGA EXPECTED OVER OUR AREA...DRY
CONDITIONS ARE CURRENTLY FORECAST THROUGH THE NEXT 24 HOURS.
SATELLITE IMAGERY INDICATES A BAND OF STRATUS OVER MUCH OF THE
NORTHERN PLAINS THIS MORNING AND THIS STRATUS IS ADVANCING TO THE
SOUTH...ABOUT 150 MILES NORTH OF THE AFOREMENTIONED SURFACE FRONT.
GUIDANCE FROM THE NAM AND RAP BOTH SHOW THIS STRATUS...WITH HIGH
RELATIVE HUMIDITY VALUES AT 925MB NOTED ON PLAN VIEW
MAPS...INFILTRATING OUR NORTH/NORTHEASTERN CWA JUST PRIOR TO
SUNRISE THIS MORNING...BUT DISSIPATING POST-SUNRISE AS DIABATIC
HEATING RESULTS IN INCREASED BOUNDARY LAYER HEIGHT AND MIXING.
WENT AHEAD AND PLAYED PRETTY CLOSE TO NAM AND RAP GUIDANCE FOR THE
CLOUD FORECAST THROUGH THE FIRST PART OF THE SHORT TERM FORECAST
PERIOD...WITH THIS STRATUS EXPECTED TO IMPACT OUR NORTH/NORTHEAST
BY 10Z OR 11Z THIS MORNING...AND THEN DISSIPATE BY 15Z OR 16Z.
WITH LOW LEVEL RETURN FLOW INFILTRATING THE REGION TONIGHT...THERE
ARE INDICATIONS OF ISENTROPIC UPGLIDE AND SATURATION...PRIMARILY
ALONG THE 275-285K SURFACES...OVER THE HIGH PLAINS OF KANSAS AND
NEBRASKA. ALTHOUGH IT APPEARS MUCH OF OUR CWA SHOULD BE SPARED
FROM ANY STRATUS DEVELOPMENT THROUGH 12Z FRIDAY...925MB RELATIVE
HUMIDITY PLAN VIEW MAPS FROM THE NAM...OPERATIONAL GFS AND EC ALL
SUGGEST OUR EXTREME WEST/SOUTHWEST COULD ACTUALLY OBSERVE QUITE A
BIT OF CLOUD COVER TOWARDS SUNRISE FRIDAY AS THE EASTERN PERIPHERY
OF THE HIGH PLAINS STRATUS CLIPS THE AREA. WENT AHEAD WITH A
BROKEN CEILING ACROSS OUR EXTREME WEST/SOUTHWEST BY 12Z FRIDAY AS
A RESULT.
THE INTRUSION OF A COOLER LOW LEVEL AIRMASS BEHIND THE LOW LEVEL
BAROCLINIC ZONE SHOULD RESULT IN A COOLER DAY TODAY WHEN COMPARED
TO WEDNESDAY. HIGH TEMPERATURES GENERALLY IN THE MID 30S ACROSS
OUR NORTH...AND INTO THE MID 40S ACROSS OUR SOUTH...ARE FORECAST
FOR TODAY AS A RESULT. IT MIGHT OTHERWISE BE REASONABLE TO THINK
TONIGHT WILL BE COOLER WHEN COMPARED TO EARLY THIS MORNING...BUT
WITH LOW LEVEL RETURN FLOW EXPECTED TO INFILTRATE OUR AREA DURING
THE OVERNIGHT HOURS...OVERNIGHT LOWS TONIGHT SHOULD ACTUALLY BE
PRETTY CLOSE TO WHAT WE ARE EXPECTING EARLY THIS MORNING.
.LONG TERM...(FRIDAY THROUGH WEDNESDAY)
ISSUED AT 332 AM CST THU NOV 28 2013
THE FIRST PART OF THE LONG TERM FORECAST IS DRY WITH ABOVE NORMAL
TEMPERATURES...AFTERWHICH A MORE UNSETTLED...COLDER AND MORE
CHALLENGING FORECAST TAKES HOLD BY MID NEXT WEEK.
A TRANSITIONING WEST/NORTHWEST UPPER LEVEL FLOW WILL KEEP THE
REGION MAINLY DRY AND MILD THROUGH THROUGH THE REMAINDER OF THE
HOLIDAY WEEKEND. REGIONAL TRAVEL CONCERNS WILL BE NIL...AND BOTH
DAYTIME HIGHS AND NIGHTTIME LOWS WILL BE AT OR SLIGHTLY ABOVE
SEASONAL NORMALS. ONE NOTABLE WEATHER ELEMENT WILL THE WIND...OR
LACK THERE OF ON SATURDAY AND SUNDAY. THAT WILL HELP OFFSET ANY
COOLING FROM PASSING CLOUDS THROUGHOUT THE WEEKEND.
OVERALL...PRETTY NICE FOR THE END OF NOVEMBER. WARM ADVECTION
ASSOCIATED WITH WAVE ACROSS THE NORTHERN PLAINS SUNDAY WILL
THICKEN CLOUDS...BUT NOT TOO EXCITED ABOUT INCURRING ANY
MEASURABLE PRECIPITATION AT THIS POINT.
ACTUALLY THE MILD WEATHER WILL CONTINUE INTO THE FIRST PART OF
NEXT WEEK...ALTHOUGH THINGS WILL BE CHANGING AS UPPER LEVEL
HEIGHTS LOWER AND WE START TO SEE UPPER LEVEL LOW PRESSURE DEEPEN
IN THE GREAT BASIN REGION. AS THE LOW STRENGTHENS...AN INCREASING
SOUTH TO SOUTHEAST FLOW ACROSS THE CENTRAL/SOUTHERN PLAINS
DEVELOPS WHICH WILL KEEP TEMPERATURES ON THE MILD SIDE
MONDAY/TUESDAY. THERE IS SOME MODEL LIKENESS IN OVERALL
TRENDS...BUT VERY UNEASY IN TRYING TO PIN DOWN ANY SPECIFIC
DETAILS FOR NEXT WEEKS FORECAST AT THIS POINT. WE HAVE BEEN
ANTICIPATING A COLD AIR PUSH NEXT WEEK...AND THAT STILL LOOKS ON
TRACK FOR ABOUT WEDNESDAY...BUT THE COLD AIR PLUNGE COMES IN
PIECES WITH THE COLDEST AIR NOT LIKELY TO MAKE IT INTO THE AREA
UNTIL LATER NEXT WEEK. MODELS SUGGEST HEAVIEST PRECIPITATION
TRENDS WILL LIKELY BE ACROSS THE DAKOTAS AT THIS POINT...WITH ONLY
SMALL CHANCES FOR RAIN OR RAIN/SNOW MIX IN THE FORECAST AT THIS
POINT AS THE SYSTEM APPROACHES.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z FRIDAY MORNING)
ISSUED AT 530 AM CST THU NOV 28 2013
MVFR CONDITIONS EXPECTED TO START THE TAF PERIOD...WITH VFR
CONDITIONS EXPECTED 15Z AND BEYOND.
AN AREA OF STRATUS HAS BEEN MOVING SOUTH FROM SOUTH DAKOTA ALL
NIGHT AND IS NOW MOVING INTO THE GRI AREA. THE CEILING WITHIN THIS
STRATUS GENERALLY RANGES BETWEEN 1000FT AND 1500FT AGL...THUS THE
MVFR FORECAST 12-15Z. GUIDANCE CONTINUES TO SUGGEST THIS STRATUS
WILL LIFT AND BREAK APART AFTER SUNRISE AS INCREASING DIABATIC
HEATING ALLOWS FOR INCREASING BOUNDARY LAYER DEPTH AND MIXING. VFR
CONDITIONS ARE CURRENTLY EXPECTED TO BE RESTORED BY 15Z...BUT THIS
WILL NEED TO BE MONITORED THROUGH THE NEXT FEW HOURS FOR POSSIBLE
UPDATES TO THE TAF. THE SURFACE WIND WILL REMAIN FROM THE
NORTH/NORTHEAST TODAY...SUSTAINED AT AROUND 10KTS. THE PASSAGE OF
A SURFACE RIDGE WILL THEN ALLOW FOR A WEAK...NO GREATER THAN
6KTS...SOUTHEASTERLY LOW LEVEL WIND FIELD OVERNIGHT TONIGHT.
VISIBILITY RESTRICTION IS NOT EXPECTED AT GRI THROUGH THE NEXT 24
HOURS.
&&
.GID WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
KS...NONE.
&&
$$
SHORT TERM...NOAA/NWS/BRYANT
LONG TERM...NOAA/NWS/MORITZ
AVIATION...NOAA/NWS/BRYANT
AREA FORECAST DISCUSSION
NWS HASTINGS NE
332 AM CST THU NOV 28 2013
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 332 AM CST THU NOV 28 2013
OVERNIGHT UPPER AIR ANALYSIS INDICATES MID TO UPPER LEVEL
TROUGHING OVER THE EASTERN CONUS...WITH A RIDGE OVER THE WEST AND
A MID LEVEL LOW OVER THE PACIFIC OFF THE CALIFORNIA COAST. A
SUBTLE MID LEVEL PERTURBATION IS ALSO NOTED OVER SOUTHERN
MINNESOTA...MOVING SOUTHEAST. MID TO UPPER LEVEL JET ENERGY
EXTENDS FROM SOUTH CENTRAL CANADA...SOUTHEAST INTO THE CENTRAL
CONUS...AND FINALLY EAST AND NORTHEAST ALONG THE EASTERN CONUS
INTO SOUTHEASTERN CANADA. MID TO UPPER LEVEL FLOW OVER OUR AREA
MAXES OUT AT AROUND 70KTS BETWEEN 300MB AND 200MB PER 00Z SOUNDING
DATA FROM KLBF AND KOAX. WATER VAPOR IMAGERY INDICATES INCREASED
VALUES OF MID LEVEL MOISTURE EXTENDING ALONG THE BACK SIDE OF THE
WEST COAST RIDGE...AS WELL AS FROM THE PACIFIC EASTWARD INTO
MEXICO AND THE SOUTHERN PLAINS. MID LEVEL MOISTURE OVER OUR AREA
HOWEVER REMAINS FAIRLY LIMITED. AT THE SURFACE...AN AREA OF LOW
BAROMETRIC PRESSURE EXISTS OVER NORTHWEST IOWA JUST AHEAD OF THE
AFOREMENTIONED MID LEVEL PERTURBATION...WITH AN ASSOCIATED COLD
FRONT EXTENDING FROM WESTERN IOWA INTO SOUTHEASTERN NEBRASKA AND
NORTHERN KANSAS. THIS FRONT HAS CLEARED MOST ALL OF OUR CWA AND AS
A RESULT...THE LOW LEVEL WIND FIELD ACROSS OUR AREA REMAINS FROM
THE NORTH/NORTHWEST.
GUIDANCE FROM THE NAM...OPERATIONAL GFS...EC AND SREF-MEAN ALL
SUGGEST NORTHWESTERLY MID TO UPPER LEVEL FLOW WILL PERSIST OVER
OUR AREA THROUGH THE NEXT 24 HOURS AS THE EASTERN CONUS TROUGH AND
WESTERN CONUS RIDGE BOTH TREK EAST. THE MID LEVEL
PERTURBATION...CURRENTLY OVER SOUTHERN MINNESOTA...IS EXPECTED TO
CONTINUE MOVING SOUTHEAST THROUGH THE NEXT 24 HOURS...WITH NO
OTHER MID LEVEL SHORTWAVES/PERTURBATIONS EXPECTED TO IMPACT THE
REGION. AT THE SURFACE...THE AREA OF LOW BAROMETRIC
PRESSURE...CURRENTLY OVER NORTHWEST IOWA...SHOULD ALSO CONTINUE
MOVING TO THE EAST/SOUTHEAST THROUGH THE NEXT 24 HOURS...WITH THE
ASSOCIATED LOW LEVEL BAROCLINIC ZONE PUSHING FARTHER
SOUTH/SOUTHEAST ACROSS THE PLAINS. THE LOW LEVEL WIND FIELD ACROSS
OUR AREA SHOULD REMAIN FROM THE NORTH/NORTHWEST THROUGH MUCH OF
TODAY AS A RESULT. THAT BEING SAID...GUIDANCE SUGGESTS THE PASSAGE
OF A SURFACE RIDGE TO EAST SHOULD ALLOW FOR LOW LEVEL RETURN FLOW
ACROSS OUR AREA DURING THE OVERNIGHT HOURS TONIGHT.
WITH AN OVERALL LACK IN OMEGA EXPECTED OVER OUR AREA...DRY
CONDITIONS ARE CURRENTLY FORECAST THROUGH THE NEXT 24 HOURS.
SATELLITE IMAGERY INDICATES A BAND OF STRATUS OVER MUCH OF THE
NORTHERN PLAINS THIS MORNING AND THIS STRATUS IS ADVANCING TO THE
SOUTH...ABOUT 150 MILES NORTH OF THE AFOREMENTIONED SURFACE FRONT.
GUIDANCE FROM THE NAM AND RAP BOTH SHOW THIS STRATUS...WITH HIGH
RELATIVE HUMIDITY VALUES AT 925MB NOTED ON PLAN VIEW
MAPS...INFILTRATING OUR NORTH/NORTHEASTERN CWA JUST PRIOR TO
SUNRISE THIS MORNING...BUT DISSIPATING POST-SUNRISE AS DIABATIC
HEATING RESULTS IN INCREASED BOUNDARY LAYER HEIGHT AND MIXING.
WENT AHEAD AND PLAYED PRETTY CLOSE TO NAM AND RAP GUIDANCE FOR THE
CLOUD FORECAST THROUGH THE FIRST PART OF THE SHORT TERM FORECAST
PERIOD...WITH THIS STRATUS EXPECTED TO IMPACT OUR NORTH/NORTHEAST
BY 10Z OR 11Z THIS MORNING...AND THEN DISSIPATE BY 15Z OR 16Z.
WITH LOW LEVEL RETURN FLOW INFILTRATING THE REGION TONIGHT...THERE
ARE INDICATIONS OF ISENTROPIC UPGLIDE AND SATURATION...PRIMARILY
ALONG THE 275-285K SURFACES...OVER THE HIGH PLAINS OF KANSAS AND
NEBRASKA. ALTHOUGH IT APPEARS MUCH OF OUR CWA SHOULD BE SPARED
FROM ANY STRATUS DEVELOPMENT THROUGH 12Z FRIDAY...925MB RELATIVE
HUMIDITY PLAN VIEW MAPS FROM THE NAM...OPERATIONAL GFS AND EC ALL
SUGGEST OUR EXTREME WEST/SOUTHWEST COULD ACTUALLY OBSERVE QUITE A
BIT OF CLOUD COVER TOWARDS SUNRISE FRIDAY AS THE EASTERN PERIPHERY
OF THE HIGH PLAINS STRATUS CLIPS THE AREA. WENT AHEAD WITH A
BROKEN CEILING ACROSS OUR EXTREME WEST/SOUTHWEST BY 12Z FRIDAY AS
A RESULT.
THE INTRUSION OF A COOLER LOW LEVEL AIRMASS BEHIND THE LOW LEVEL
BAROCLINIC ZONE SHOULD RESULT IN A COOLER DAY TODAY WHEN COMPARED
TO WEDNESDAY. HIGH TEMPERATURES GENERALLY IN THE MID 30S ACROSS
OUR NORTH...AND INTO THE MID 40S ACROSS OUR SOUTH...ARE FORECAST
FOR TODAY AS A RESULT. IT MIGHT OTHERWISE BE REASONABLE TO THINK
TONIGHT WILL BE COOLER WHEN COMPARED TO EARLY THIS MORNING...BUT
WITH LOW LEVEL RETURN FLOW EXPECTED TO INFILTRATE OUR AREA DURING
THE OVERNIGHT HOURS...OVERNIGHT LOWS TONIGHT SHOULD ACTUALLY BE
PRETTY CLOSE TO WHAT WE ARE EXPECTING EARLY THIS MORNING.
.LONG TERM...(FRIDAY THROUGH WEDNESDAY)
ISSUED AT 332 AM CST THU NOV 28 2013
THE FIRST PART OF THE LONG TERM FORECAST IS DRY WITH ABOVE NORMAL
TEMPERATURES...AFTERWHICH A MORE UNSETTLED...COLDER AND MORE
CHALLENGING FORECAST TAKES HOLD BY MID NEXT WEEK.
A TRANSITIONING WEST/NORTHWEST UPPER LEVEL FLOW WILL KEEP THE
REGION MAINLY DRY AND MILD THROUGH THROUGH THE REMAINDER OF THE
HOLIDAY WEEKEND. REGIONAL TRAVEL CONCERNS WILL BE NIL...AND BOTH
DAYTIME HIGHS AND NIGHTTIME LOWS WILL BE AT OR SLIGHTLY ABOVE
SEASONAL NORMALS. ONE NOTABLE WEATHER ELEMENT WILL THE WIND...OR
LACK THERE OF ON SATURDAY AND SUNDAY. THAT WILL HELP OFFSET ANY
COOLING FROM PASSING CLOUDS THROUGHOUT THE WEEKEND.
OVERALL...PRETTY NICE FOR THE END OF NOVEMBER. WARM ADVECTION
ASSOCIATED WITH WAVE ACROSS THE NORTHERN PLAINS SUNDAY WILL
THICKEN CLOUDS...BUT NOT TOO EXCITED ABOUT INCURRING ANY
MEASURABLE PRECIPITATION AT THIS POINT.
ACTUALLY THE MILD WEATHER WILL CONTINUE INTO THE FIRST PART OF
NEXT WEEK...ALTHOUGH THINGS WILL BE CHANGING AS UPPER LEVEL
HEIGHTS LOWER AND WE START TO SEE UPPER LEVEL LOW PRESSURE DEEPEN
IN THE GREAT BASIN REGION. AS THE LOW STRENGTHENS...AN INCREASING
SOUTH TO SOUTHEAST FLOW ACROSS THE CENTRAL/SOUTHERN PLAINS
DEVELOPS WHICH WILL KEEP TEMPERATURES ON THE MILD SIDE
MONDAY/TUESDAY. THERE IS SOME MODEL LIKENESS IN OVERALL
TRENDS...BUT VERY UNEASY IN TRYING TO PIN DOWN ANY SPECIFIC
DETAILS FOR NEXT WEEKS FORECAST AT THIS POINT. WE HAVE BEEN
ANTICIPATING A COLD AIR PUSH NEXT WEEK...AND THAT STILL LOOKS ON
TRACK FOR ABOUT WEDNESDAY...BUT THE COLD AIR PLUNGE COMES IN
PIECES WITH THE COLDEST AIR NOT LIKELY TO MAKE IT INTO THE AREA
UNTIL LATER NEXT WEEK. MODELS SUGGEST HEAVIEST PRECIPITATION
TRENDS WILL LIKELY BE ACROSS THE DAKOTAS AT THIS POINT...WITH ONLY
SMALL CHANCES FOR RAIN OR RAIN/SNOW MIX IN THE FORECAST AT THIS
POINT AS THE SYSTEM APPROACHES.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z THURSDAY NIGHT)
ISSUED AT 1133 PM CST WED NOV 27 2013
VFR CONDITIONS EXPECTED THROUGH 11Z...WITH MVFR CONDITIONS
FORECAST 11-18Z...FOLLOWED BY VFR CONDITIONS 18Z ONWARD.
LITTLE IN THE WAY OF CLOUD COVER WILL BE OBSERVED TO START THE TAF
PERIOD. STRATUS...CURRENTLY OVER SOUTH DAKOTA...IS SURGING TOWARD
THE AREA AND MAY IMPACT THE AREA TOWARDS SUNRISE THURSDAY. BASED
ON CURRENT OBSERVATIONS ACROSS SOUTH DAKOTA...AS WELL AS CURRENT
GUIDANCE...WENT AHEAD WITH A CEILING AROUND 1500FT AGL STARTING AT
11Z. THE SURFACE WIND WILL REMAIN FROM THE NORTH/NORTHWEST AT
AROUND 10KTS THROUGH THE OVERNIGHT HOURS AND INTO THURSDAY
MORNING...THEN BECOMING LIGHT AND VARIABLE HEADING INTO THE
AFTERNOON HOURS THURSDAY. VISIBILITY RESTRICTION IS NOT EXPECTED
AT GRI THROUGH THE NEXT 24 HOURS.
&&
.GID WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
KS...NONE.
&&
$$
SHORT TERM...NOAA/NWS/BRYANT
LONG TERM...NOAA/NWS/MORITZ
AVIATION...NOAA/NWS/BRYANT
AREA FORECAST DISCUSSION
NWS BINGHAMTON NY
131 AM EST THU NOV 28 2013
.SYNOPSIS...
A STORM SYSTEM OVER NEW ENGLAND WILL CONTINUE MOVING NORTHEAST
TONIGHT. STEADY SNOW WILL END THIS EVENING, BUT LAKE EFFECT SNOW
SHOWERS WILL SET UP ACROSS UPSTATE NEW YORK TONIGHT AND CONTINUE
INTO THANKSGIVING NIGHT. HIGH PRESSURE AND DRY WEATHER WILL RETURN
FRIDAY NIGHT TO SATURDAY NIGHT.
&&
.NEAR TERM /UNTIL 6 AM THIS MORNING/...
920 PM UPDATE...
REDUCED OVERNIGHT SNOWFALL AMOUNTS IN PROJECTED BANDS FROM AROUND
2 TO 3 INCHES, DOWN TO 1.5 TO 2 INCHES. THIS IS MOSTLY FROM A
REDUCTION IN THE FIRST 6 HOURS, AS BAND INTO SYR AREA HAS NOT YET
SHOWN SIGNS OF FORMING. LATEST HRRR HAS A PRETTY GOOD HANDLE ON
THE RADAR DEPICTION, AND IT KEEPS THE RETURNS PRETTY LIGHT THROUGH
THE NEXT FEW HOURS.
STILL ANTICIPATE BAND INTENSIFICATION SOMETIME BETWEEN 7Z AND 9Z,
WITH MOST OF THE OVERNIGHT SNOW ACCUMULATION COMING IN THE FINAL 6
HOURS OF THE OVERNIGHT PERIOD.
515 PM UPDATE...
QUICK UPDATE TO LOWER POPS TO SLIGHT CHANCE OVER NY COUNTIES WEST
OF I-81 IN LOWER DEWPOINT ATMOSPHERE. BACK EDGE OF SYNOPTIC SNOW IS ALONG
THE I-81 CORRIDOR EASTWARD. WESTWARD - JUST A FEW RADAR RETURNS
AND MAJORITY OF OBS ARE REPORTING DRY WEATHER. AS THE EVENING
WEARS ON...THE EVENT WILL TRANSITION TO LAKE EFFECT OVER NORTHERN
FA.
3 PM UPDATE...
BACK EDGE OF SYNOPTIC PRECIP STILL IN NE PA AND THE CATSKILLS.
RAIN HAS NOW MOSTLY CHANGED TO SNOW. THIS WILL LIFT NE BY 6 PM AS
THE LARGE SFC LOW IN EASTERN NEW ENGLAND. NW FLOW ACROSS THE
ENTIRE CWA WITH WEAK LAKE EFFECT STARTING. AS THE LOW LEVEL FLOW
ALIGNS AND COLDER AIR COMES IN THE LAKE EFFECT SNOW WILL EXPAND IN
COVERAGE AND INCREASE IN INTENSITY. WITH A 320 FLOW IT WILL BE
MULTIBANDS. GEORGIAN BAY CONNECTION COMES INTO PLAY AS THE FLOW
SHIFTS SOME TO WNW. MOISTURE DEPTH OF 10KT. DENDRITE ZONE OF 2K FT
STARTS AROUND 6K THEN DROPS TO 4K LATE TONIGHT. GOOD LIFT THROUGH
THE MOISTURE AND DENDRITE ZONES. ISSUED A LES ADVISORY FOR
ONONDAGA ONEIDA MADISON FOR TONIGHT TO THU NGT.
OUTSIDE OF THE LAKE EFFECT IN CENTRAL NY...NE PA WILL BE CLOUDY
AND MOSTLY DRY. CAA IS STRONG WITH TEMPS FALLING UPPER TEENS AND
L20S.
&&
.SHORT TERM /6 AM THIS MORNING THROUGH SATURDAY/...
3 PM UPDATE...
THU MORNING A LULL BEFORE A SHORT WAVE DROPS SE HELPING TO ENHANCE
THE LAKE EFFECT. LOW LEVEL FLOW SHIFTS TO 290 BRINGING THE BEST
BAND INTO SYRACUSE AND ONEIDA AND CAZENOVIA. THIS BAND WILL
CONTINUE INTO THE EVENING BEFORE WEAKENING LATE THU NGT. MULTILAKE
CONNECTION FROM GEORGIAN BAY. COULD BE A GOOD ENOUGH BAND FOR
HALF AN INCH TO AN INCH AN HOUR SNOW. HEAVIEST SNOW TOTALS THU PM
3 TO 5 INCHES.
FRIDAY COLD NW LOW LEVEL FLOW STILL GOING AS A LARGE DRY CANADIAN
HIGH PRESSURE MOVES IN FROM THE NW. LL FLOW BECOMES LIGHT AND IS
SHEARED SO SNOW ACCUMULATIONS WILL BE LESS THAN 2 INCHES
EVERYWHERE BEFORE LES SHUTS DOWN FRI AFTN. HIGH OVER THE CWA FRI
NGT AND STALLS INTO SAT NGT. WAA AT 850MB KICKS IN WHILE UPPER
LEVEL HEIGHTS RISE. SFC TEMPS STILL BELOW NORMAL AND MOSTLY BELOW
FREEZING.
&&
.LONG TERM /SATURDAY NIGHT THROUGH WEDNESDAY/...
PD BEGINS WITH A WEAK WV DROPPING THRU THE GREAT LAKES. DFRNCS
BETWEEN THE EURO AND GFS WILL HAVE LTL EFFECT ON THE SENSIBLE WX
FOR THE SYSTEM WHICH LOOKS TO GENERATE SOME LGT PCPNSAT NGT INTO
SUNDAY. TEMPS MRGNL...BUT LOOKS COLD ENUF FOR SOME LGT SNOW MOST
PLACE...ESP NORTH. SLGTLY MILDER OVER NEPA BUT WITH A LWR CHANCE
PF PCPN IT MAY NOT MAKE MUCH DFRNC. SYSTEM, PASSES THRU SUN BUT
LEAVES THE AREA IN A SHALLOW UT BROAD UPR TROF OVER THE
LAKES...AND WEAK AREA OF MOISTURE PCPN. EURO SUGGESTS SOME WEAK
CSTL DVLPMT ON TUE PERHAPS ORGANIZING THE PCPN A BIT MORE. GFS HAS
DVLPMT FURTHER OUT TO SEA BUT STILL SOME ENHANCED PCPN OVER THE
ERN ZONES. HWVR...IN GNRL JUST A SEASONABLY COOL PD WITH LGT PCPN
AT TIMES.
&&
.AVIATION /06Z THURSDAY THROUGH MONDAY/...
A BRISK NORTHWEST FLOW WILL PREVAIL ACROSS THE AREA THROUGH THIS
TAF PERIOD WITH WIDESPREAD MVFR CIGS AND FLURRIES EXPECTED AT ALL
TERMINALS EXCEPT FOR KELM/KAVP WHERE CONDITIONS WILL BE PRIMARILY
VFR.
AT KSYR, A LAKE EFFECT SNOWBAND CONTINUES TO PRODUCE IFR
RESTRICTIONS NOW. IT APPEARS BASED ON RADAR AND MODEL SOUNDINGS
SHOWING DRIER AIR WORKING IN FROM ABOVE...THAT THE BEST SHOT FOR
IFR WILL COME OVER THE NEXT FEW HOURS. WITH THE 09Z UPDATE I MAY
HAVE TO REMOVE IFR VSBYS THAT WE CURRENTLY HAVE NEAR DAYBREAK.
LATER TODAY AS MOISTURE INCREASES IN THE COLUMN...MORE LAKE SNOWS
ARE POSSIBLE ESPECIALLY AT KRME AND KSYR WITH IFR VSBYS POSSIBLE.
NORTHWEST WINDS 10-15 KNOTS WITH GUSTS AROUND 25 KNOTS DIMINISHING
TO 10-12 KNOTS BY MID MORNING THURSDAY.
OUTLOOK...
THU NIGHT TO SUN MORN...MAINLY VFR.
SUN AFTN TO MON...MVFR AND MAYBE IFR IN MIXED PRECIP.
&&
.BGM WATCHES/WARNINGS/ADVISORIES...
PA...NONE.
NY...LAKE EFFECT SNOW ADVISORY UNTIL 7 AM EST FRIDAY FOR NYZ009-018-
036-037.
&&
$$
SYNOPSIS...TAC
NEAR TERM...DJP/TAC
SHORT TERM...TAC
LONG TERM...DGM
AVIATION...HEDEN/RRM
AREA FORECAST DISCUSSION
NWS BISMARCK ND
306 PM CST THU NOV 28 2013
.SHORT TERM...(THIS EVENING THROUGH FRIDAY)
ISSUED AT 306 PM CST THU NOV 28 2013
THE MAIN FORECAST ISSUE IN THE SHORT TERM PERIOD WILL BE SKY COVER
TONIGHT AND IMPACT ON TEMPERATURES.
PORTIONS OF THE STRATUS DECK HAVE ERODED ACROSS THE FORECAST AREA
THIS AFTERNOON. RAP 925MB RELATIVE HUMIDITY HAS THIS MODELED
RELATIVELY WELL AND SUGGEST THAT STRATUS SHOULD FILL BACK IN THIS
EVENING AND OVERNIGHT. TEMPERATURES WILL LIKELY DROP QUICKLY THIS
EVENING IN CLOUD FREE AREAS...BEFORE THE STRONGER SE WINDS
DEVELOP. THE STRONGER GRADIENT WILL BE LOCATED OVER THE WEST AND
HAVE KEPT OVERNIGHT LOWS RELATIVELY MILD...IN THE TEENS TO LOWER
20S. EAST/NORTHEAST PORTIONS OF THE FORECAST AREA...FROM THE
TURTLE MOUNTAINS THROUGH THE JAMES RIVER VALLEY...SHOULD BE ABLE
TO GET INTO THE SINGLE DIGITS. HOURLY TRENDS WILL LIKELY NEED TO
BE UPDATED THIS EVENING.
ON FRIDAY...STRONGER WARM AIR ADVECTION WILL KICK IN...WITH HIGHS
IN THE MID 20S NORTHEAST TO LOWER 40S SOUTHWEST.
.LONG TERM...(FRIDAY NIGHT THROUGH THURSDAY)
ISSUED AT 306 PM CST THU NOV 28 2013
THE HIGHLIGHT OF THE EXTENDED FORECAST IS THE RETURN OF ARCTIC AIR
AND THE POTENTIAL FOR WIDESPREAD ACCUMULATING SNOW NEXT WEEK.
THE 12 UTC GUIDANCE SUITE IS IN GOOD AGREEMENT ON A SIGNIFICANT
UPPER LEVEL LOW COMING ONSHORE TO THE PACIFIC NORTHWEST ON MONDAY.
THEREAFTER...UNCERTAINTY INCREASES IN REGARDS TO THE EVOLUTION AND
PROPAGATION OF THIS LOW ACROSS THE INTERMOUNTAIN WEST AND
POTENTIALLY INTO THE NORTHERN PLAINS LATE TUESDAY AND INTO
WEDNESDAY. THE 12 UTC ECMWF CONTINUES THE TREND OF ITS PREVIOUS
RUNS OVER THE PAST 24 HOURS OF THE DEEPEST LOW YIELDING
SIGNIFICANT QPF AND SNOW ACROSS THE NORTHERN PLAINS TUESDAY INTO
WEDNESDAY. THE 12 UTC GFS HAS TRENDED MORE TOWARDS THE
ECMWF...HOWEVER...IS NOT AS DEEP WITH LESSER QPF...MUCH LIKE THE
12 UTC GEM. THE ECMWF HAS BEEN THE MOST CONSISTENT AND IS
SUPPORTED BY THE GEFS MEAN...AND FAVORED BY WPC. THUS...WILL
CONTINUE TO MONITOR THE POTENTIAL FOR ACCUMULATING SNOW NEXT WEEK.
NO MATTER THE MODEL...ARCTIC AIR IS FORECAST TO OVERTAKE THE
NORTHERN PLAINS ONCE AGAIN TUESDAY THROUGH THE END OF NEXT WEEK
WITH A PATTERN SHIFT TO BROAD WESTERN AND CENTRAL CONUS UPPER
LEVEL TROUGHING.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z FRIDAY AFTERNOON)
ISSUED AT 306 PM CST THU NOV 28 2013
EXPECT MAINLY MVFR CEILINGS THROUGH TONIGHT...WITH SOME PERIODS
THIS AFTERNOON WHEN CLOUDS SCATTER OUT...ESPECIALLY AT
KDIK/KJMS/KMOT. A FEW FLURRIES WILL PERSIST.
&&
.BIS WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM/AVIATION...RP KINNEY
LONG TERM...AYD
AREA FORECAST DISCUSSION
NWS GRAND FORKS ND
1234 PM CST THU NOV 28 2013
.UPDATE...
ISSUED AT 1228 PM CST THU NOV 28 2013
TEMPERATURES HAVE BEEN SLOW TO RECOVER OVER PORTIONS OF NW MN
LIKELY A RESULT OF FRESH SNOW COVER AND LOWERED MAXIMUM
TEMPERATURES 3-5 DEGREES. TEMPERATURES ON TRACK ELSEWHERE WHERE
PARTIAL SOLAR HELPING THE SLIGHT RECOVERY EXPECTED. NO OTHER
CHANGES MADE TO ONGOING FORECAST.
UPDATE ISSUED AT 936 AM CST THU NOV 28 2013
MAIN CHALLENGE TODAY WILL BE CLOUD TRENDS AND TEMPERATURES. LATEST
SATELLITE IMAGERY SHOWING A GENERAL DECREASE IN CLOUD COVER ACROSS
THE REGION BEST DEPICTED BY RAP MESO-MODEL. WILL CONTINUE WITH A
GRADUAL DECREASE IN CLOUDS THROUGH THE MORNING BASED ON RAP
GUIDANCE AND CURRENT TRENDS. AT THIS POINT WITH EXPECTED PARTIAL SOLAR
WILL HOLD WITH TEMPERATURES FOR NOW. ONLY CHANGES WERE MINOR CLOUD
TREND ADJUSTMENTS.
UPDATE ISSUED AT 641 AM CST THU NOV 28 2013
CLOUDS CONTINUE TO BE A CHALLENGE. RAP/HRRR CIG GUIDANCE
INITIALIZES WITH CLEAR SKIES...BUT THEN DEVELOPS LOW CIGS DURING
THE AFTERNOON HOURS (LIKELY CU...LOW CONVECTIVE TEMPS) WHICH GET
TRAPPED UNDER THE RIDGE TONIGHT. RAP 925MB-850MB RH FIELD
ACTUALLY INDICATES THE DRYING THAT IS WORKING THROUGH THE
VALLEY...AND PROBABLY IS CLOSEST TO THE TRUTH. ADJUSTED THE SKY
GRIDS FOR CURRENT OBSERVATIONS AND LATEST RAP 925MB-850MB RH. NO
MAJOR CHANGES YET UNTIL MORE CONFIDENCE CAN BE OBTAINED WITH WHAT
EVER THE CLOUDS WILL DO TODAY.
&&
.SHORT TERM...(TODAY THROUGH FRIDAY)
ISSUED AT 300 AM CST THU NOV 28 2013
NORTHWEST FLOW ALOFT WILL CONTINUE INTO FRIDAY...WITH ANOTHER
SHORTWAVE EXPECTED FRIDAY INTO FRIDAY NIGHT. 00Z MODELS INDICATE
THAT THIS NEXT SHORTWAVE WILL TRACK FURTHER NORTH THAN THE ONE
YESTERDAY...KEEPING ACCUMULATING SNOWFALL OUTSIDE OF THE FA.
FOR TODAY...THE REGION WILL BE BETWEEN SHORTWAVES AS HIGH PRESSURE
BUILDS FROM THE NORTH. THIS WILL LEAVE CLOUD TRENDS AS THE MAIN
CHALLENGE. 09Z SATELLITE IMAGERY SHOWS CLEARING WORKING INTO THE
NORTHERN VALLEY. MODELS ARE STRUGGLING WITH THE CURRENT CLOUD
COVER...ALTHOUGH THE 07Z RAP IS CLOSEST WHEN LOOKING AT THE 925MB-
850MB RH FIELD. THIS MODEL INDICATES THAT CLEARING WILL CONTINUE
TO MOVE DOWN THE VALLEY...WITH CLOUDS DISSIPATING ALONG BOTH
EDGES THROUGH THE DAY. THIS SCENARIO MAKES SOME SENSE WITH THE
HIGH BUILDING INTO THE REGION. HOWEVER...CONVECTIVE TEMPS WILL BE
IN THE TEENS UNTIL LATE AFTERNOON...WHICH COULD LEAD TO
REDEVELOPMENT WITHIN CLEARING AREAS. DID DELAY THE CLEARING...BUT
REMAINED OPTIMISTIC THAT MOST AREAS WILL CLEAR THIS AFTERNOON.
ALSO...CONSIDERING CURRENT CONDITIONS...MENTIONED FLURRIES WITHIN
EXPECTED CLOUDY AREAS.
MIN TEMPS TONIGHT VERY DEPENDENT ON WHETHER OR NOT WE GET RID OF
THE CLOUDS TODAY. IF WE DO CLEAR...THERE WILL LIKELY WILL BE A
QUICK DROP THIS EVENING BEFORE RETURN FLOW KICKS IN AND TEMPS
BECOME STEADY AFTER MIDNIGHT.
.LONG TERM...(FRIDAY NIGHT THROUGH WEDNESDAY)
ISSUED AT 300 AM CST THU NOV 28 2013
FRIDAY NIGHT-SATURDAY NIGHT...HIGH PRESSURE MOVING THROUGH SHOULD
LEAD TO DRY WEATHER. NOT SURE ABOUT CLOUD COVER (CONSIDERING
CURRENT CONDITIONS FOLLOWING A SHORTWAVE). CURRENT THOUGHT IS THAT
SINCE THE FRIDAY SHORTWAVE WILL TRACK FURTHER NORTH THAN THE
CURRENT SYSTEM...SHOULD BE LESS CLOUDS. ALSO...ANTICIPATE A WARMER
AIRMASS.
SUNDAY-WEDNESDAY...DETERMINISTIC MODEL RUNS CONTINUE TO SUGGEST A
MORE ACTIVE PATTERN TAKING SHAPE NEXT WEEK AS AN UPPER WAVE
CURRENTLY ACROSS ALASKA DIVES SOUTHWARD INTO THE WESTERN CONUS
DURING THE FIRST HALF OF NEXT WEEK...WITH ZONAL FLOW TRANSITIONING
TO SOUTHWEST FLOW ALOFT DOWNSTREAM ACROSS THE PLAINS. 00Z MODELS
SUGGEST THE POTENTIAL FOR SOME LIGHT SNOW WITH WARM ADVECTION LATER
SUNDAY INTO MONDAY. BEYOND THIS POINT...CONFIDENCE REGARDING ANY
PARTICULAR DETAILS IS VERY LOW...WITH SIGNIFICANT DIFFERENCES AMONG
MODELS IN HANDLING THE UPPER LONGWAVE TROUGH AND TIMING/PLACEMENT
OF EMBEDDED SHORTWAVE TROUGHS. THE LOW TO MID-LEVEL BAROCLINIC ZONE
WILL REMAIN POSITIONED ACROSS THE NORTHERN PLAINS THROUGH MID-WEEK
BEFORE ADVANCING SOUTHWARD. ANY WAVE EJECTING OUT OF THE BROADER
TROUGH TO THE WEST ALONG THIS BAROCLINIC ZONE WILL NEED TO BE
WATCHED FOR SFC CYCLONE DEVELOPMENT...WITH THE 00Z ECMWF INDICATING
A MORE SIGNIFICANT WAVE FOR THE MIDDLE OF THE WEEK. GIVEN THE VARIED
MODEL SOLUTIONS...CONTINUED WITH BROAD BRUSHED SLIGHT/CHANCE POPS
THROUGH MUCH OF THE PERIOD. TEMPS THROUGH MID-WEEK LOOK TO BE
SEASONABLE BEFORE COLDER AIR ARRIVES LATE IN THE WEEK.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z FRIDAY AFTERNOON)
ISSUED AT 1228 PM CST THU NOV 28 2013
MVFR CEILINGS WITH PATCHY LIGHT SNOW/FLURRIES CONTINUE ACROSS THE FAR
EASTERN PORTIONS OF THE FA...THIS INCLUDES KTVF AND KBJI.
OTHERWISE...SKIES HAVE UNDERGONE A CLEARING TREND IN THE HEART OF
THE RED RIVER VALLEY AND SOUTHERN PORTIONS OF THE FA. THESE TRENDS
SHOULD CONTINUE FOR THE REMAINDER OF THE DAYLIGHT HOURS. CLOUD
COVER IS THEN EXPECTED TO INCREASE AGAIN ACROSS THE NORTHERN FA
AFTER 00Z AND CONTINUING OVERNIGHT. SURFACE WINDS WILL SLACKEN IN
THE EVENING AND THEN BEGIN TO TURN AROUND OUT OF THE SOUTHEAST AS
THE SURFACE RIDGE PASSES TO THE EAST OF THE REGION. THE WINDS
SHOULD INCREASE AFTER SUNRISE ON FRIDAY AND GUST TO AROUND 20
KNOTS.
&&
.FGF WATCHES/WARNINGS/ADVISORIES...
ND...NONE.
MN...NONE.
&&
$$
UPDATE...VOELKER
SHORT TERM...TG
LONG TERM...TG/MAKOWSKI
AVIATION...BRAMER
AREA FORECAST DISCUSSION
NWS GRAND FORKS ND
940 AM CST THU NOV 28 2013
.UPDATE...
ISSUED AT 936 AM CST THU NOV 28 2013
MAIN CHALLENGE TODAY WILL BE CLOUD TRENDS AND TEMPERATURES. LATEST
SATELLITE IMAGERY SHOWING A GENERAL DECREASE IN CLOUD COVER ACROSS
THE REGION BEST DEPICTED BY RAP MESO-MODEL. WILL CONTINUE WITH A
GRADUAL DECREASE IN CLOUDS THROUGH THE MORNING BASED ON RAP
GUIDANCE AND CURRENT TRENDS. AT THIS POINT WITH EXPECTED PARTIAL SOLAR
WILL HOLD WITH TEMPERATURES FOR NOW. ONLY CHANGES WERE MINOR CLOUD
TREND ADJUSTMENTS.
UPDATE ISSUED AT 641 AM CST THU NOV 28 2013
CLOUDS CONTINUE TO BE A CHALLENGE. RAP/HRRR CIG GUIDANCE
INITIALIZES WITH CLEAR SKIES...BUT THEN DEVELOPS LOW CIGS DURING
THE AFTERNOON HOURS (LIKELY CU...LOW CONVECTIVE TEMPS) WHICH GET
TRAPPED UNDER THE RIDGE TONIGHT. RAP 925MB-850MB RH FIELD
ACTUALLY INDICATES THE DRYING THAT IS WORKING THROUGH THE
VALLEY...AND PROBABLY IS CLOSEST TO THE TRUTH. ADJUSTED THE SKY
GRIDS FOR CURRENT OBSERVATIONS AND LATEST RAP 925MB-850MB RH. NO
MAJOR CHANGES YET UNTIL MORE CONFIDENCE CAN BE OBTAINED WITH WHAT
EVER THE CLOUDS WILL DO TODAY.
&&
.SHORT TERM...(TODAY THROUGH FRIDAY)
ISSUED AT 300 AM CST THU NOV 28 2013
NORTHWEST FLOW ALOFT WILL CONTINUE INTO FRIDAY...WITH ANOTHER
SHORTWAVE EXPECTED FRIDAY INTO FRIDAY NIGHT. 00Z MODELS INDICATE
THAT THIS NEXT SHORTWAVE WILL TRACK FURTHER NORTH THAN THE ONE
YESTERDAY...KEEPING ACCUMULATING SNOWFALL OUTSIDE OF THE FA.
FOR TODAY...THE REGION WILL BE BETWEEN SHORTWAVES AS HIGH PRESSURE
BUILDS FROM THE NORTH. THIS WILL LEAVE CLOUD TRENDS AS THE MAIN
CHALLENGE. 09Z SATELLITE IMAGERY SHOWS CLEARING WORKING INTO THE
NORTHERN VALLEY. MODELS ARE STRUGGLING WITH THE CURRENT CLOUD
COVER...ALTHOUGH THE 07Z RAP IS CLOSEST WHEN LOOKING AT THE 925MB-
850MB RH FIELD. THIS MODEL INDICATES THAT CLEARING WILL CONTINUE
TO MOVE DOWN THE VALLEY...WITH CLOUDS DISSIPATING ALONG BOTH
EDGES THROUGH THE DAY. THIS SCENARIO MAKES SOME SENSE WITH THE
HIGH BUILDING INTO THE REGION. HOWEVER...CONVECTIVE TEMPS WILL BE
IN THE TEENS UNTIL LATE AFTERNOON...WHICH COULD LEAD TO
REDEVELOPMENT WITHIN CLEARING AREAS. DID DELAY THE CLEARING...BUT
REMAINED OPTIMISTIC THAT MOST AREAS WILL CLEAR THIS AFTERNOON.
ALSO...CONSIDERING CURRENT CONDITIONS...MENTIONED FLURRIES WITHIN
EXPECTED CLOUDY AREAS.
MIN TEMPS TONIGHT VERY DEPENDENT ON WHETHER OR NOT WE GET RID OF
THE CLOUDS TODAY. IF WE DO CLEAR...THERE WILL LIKELY WILL BE A
QUICK DROP THIS EVENING BEFORE RETURN FLOW KICKS IN AND TEMPS
BECOME STEADY AFTER MIDNIGHT.
.LONG TERM...(FRIDAY NIGHT THROUGH WEDNESDAY)
ISSUED AT 300 AM CST THU NOV 28 2013
FRIDAY NIGHT-SATURDAY NIGHT...HIGH PRESSURE MOVING THROUGH SHOULD
LEAD TO DRY WEATHER. NOT SURE ABOUT CLOUD COVER (CONSIDERING
CURRENT CONDITIONS FOLLOWING A SHORTWAVE). CURRENT THOUGHT IS THAT
SINCE THE FRIDAY SHORTWAVE WILL TRACK FURTHER NORTH THAN THE
CURRENT SYSTEM...SHOULD BE LESS CLOUDS. ALSO...ANTICIPATE A WARMER
AIRMASS.
SUNDAY-WEDNESDAY...DETERMINISTIC MODEL RUNS CONTINUE TO SUGGEST A
MORE ACTIVE PATTERN TAKING SHAPE NEXT WEEK AS AN UPPER WAVE
CURRENTLY ACROSS ALASKA DIVES SOUTHWARD INTO THE WESTERN CONUS
DURING THE FIRST HALF OF NEXT WEEK...WITH ZONAL FLOW TRANSITIONING
TO SOUTHWEST FLOW ALOFT DOWNSTREAM ACROSS THE PLAINS. 00Z MODELS
SUGGEST THE POTENTIAL FOR SOME LIGHT SNOW WITH WARM ADVECTION LATER
SUNDAY INTO MONDAY. BEYOND THIS POINT...CONFIDENCE REGARDING ANY
PARTICULAR DETAILS IS VERY LOW...WITH SIGNIFICANT DIFFERENCES AMONG
MODELS IN HANDLING THE UPPER LONGWAVE TROUGH AND TIMING/PLACEMENT
OF EMBEDDED SHORTWAVE TROUGHS. THE LOW TO MID-LEVEL BAROCLINIC ZONE
WILL REMAIN POSITIONED ACROSS THE NORTHERN PLAINS THROUGH MID-WEEK
BEFORE ADVANCING SOUTHWARD. ANY WAVE EJECTING OUT OF THE BROADER
TROUGH TO THE WEST ALONG THIS BAROCLINIC ZONE WILL NEED TO BE
WATCHED FOR SFC CYCLONE DEVELOPMENT...WITH THE 00Z ECMWF INDICATING
A MORE SIGNIFICANT WAVE FOR THE MIDDLE OF THE WEEK. GIVEN THE VARIED
MODEL SOLUTIONS...CONTINUED WITH BROAD BRUSHED SLIGHT/CHANCE POPS
THROUGH MUCH OF THE PERIOD. TEMPS THROUGH MID-WEEK LOOK TO BE
SEASONABLE BEFORE COLDER AIR ARRIVES LATE IN THE WEEK.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z FRIDAY MORNING)
ISSUED AT 641 AM CST THU NOV 28 2013
LOW CONFIDENCE FORECAST FOR TODAY AS GUIDANCE IS PERFORMING POORLY
WITH THE CURRENT SITUATION. THE MOST LIKELY SCENARIO IS THAT MVFR
CIGS WILL REMAIN WEST OF THE VALLEY THROUGH MUCH OF THE
DAY...BREAKING UP BY THIS EVENING. SKY WITHIN THE VALLEY
(KGFK/KFAR) IS CURRENTLY CLEAR...AND SHOULD REMAIN THAT WAY (WITH
A BRIEF PERIOD OF MVFR CU DEVELOPMENT MID-DAY). ANTICIPATE
CLEARING EAST OF THE VALLEY BY EARLY TO MID AFTERNOON. WILL AMEND
THE TAFS IF MORE CONFIDENCE CAN BE OBTAINED.
&&
.FGF WATCHES/WARNINGS/ADVISORIES...
ND...NONE.
MN...NONE.
&&
$$
UPDATE...VOELKER
SHORT TERM...TG
LONG TERM...TG/MAKOWSKI
AVIATION...TG
AREA FORECAST DISCUSSION
NWS BISMARCK ND
646 AM CST THU NOV 28 2013
.UPDATE...
ISSUED AT 646 AM CST THU NOV 28 2013
HIGH RESOLUTION MODELS INCLUDING RAP AND NAM NOT SHOWING MUCH
INDICATION OF LOW STRATUS SCATTERING OUT ANYTIME SOON. LATEST
SATELLITE IMAGERY DOES SHOW CLEARING WORKING SOUTH INTO
SOUTHWESTERN MANITOBA...AND THE LATEST RAP DOES DEPICT THIS AND
CONTINUES THE CLEARING SOUTH. THUS TRENDING SKY CONDITIONS SCT-BKN
OVER MY EAST AS THIS CLEARING DEVELOPS SOUTHWARD. MODELS ALSO
INDICATING THE WESTERN EDGE OF THE STRATUS DECK ERODING SO
TRENDED SKY OVER SOUTHWEST ND SCT-BKN AS WELL. OTHERWISE DO NOT
SEE CIGS SCOURING OUT TODAY ELSEWHERE. PIREP REPORTS FROM LAST
EVENING INDICATED THE THICKNESS OF THE STRATUS DECK AT AROUND
1500FT...SO MAY ONLY SEE THE EDGES ERODING TODAY WITH
REDEVELOPMENT TONIGHT.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 419 AM CST THU NOV 28 2013
CURRENTLY...ARCTIC HIGH PRESSURE WAS CENTERED OVER NORTHERN
MANITOBA...WITH ITS AXIS EXTENDING SOUTHWESTWARD TO THE
MONTANA/NORTH DAKOTA BORDER. A WIDE AREA OF STRATUS CLOUDS WAS
SITUATED ON THE WESTERN AND SOUTHERN FRINGES OF THE ARCTIC HIGH. THE
STRATUS CLOUDS EXTENDED FROM NORTHERN ALBERTA/SASKATCHEWAN ACROSS
NORTHEASTERN MONTANA...ALL OF NORTH DAKOTA...MOST OF MINNESOTA AND
SOUTH DAKOTA...AND THE LEADING EDGE OF THE SOUTHERNMOST EXTENT WAS
NOSING INTO NORTHEASTERN NEBRASKA.
THE MAIN FORECAST CHALLENGES TODAY ARE SKY COVER AND TEMPERATURES.
THE STRATUS CLOUDS HAVE INHIBITED RADIATIONAL COOLING DURING THE
NIGHTTIME HOURS...AND THINK THE MORNING LOW TEMPERATURES OVER
WESTERN AND CENTRAL NORTH DAKOTA WILL BE HIGHER THAN FORECAST.
THE ARCTIC HIGH IS FORECAST TO MOVE EAST/SOUTHEAST TODAY...SUCH THAT
THE HIGH AXIS WOULD CROSS THE STATE WEST-TO-EAST AND THE AXIS WOULD
LIE ACROSS MINNESOTA/IOWA BY THIS EVENING...THEN CONTINUE MOVING
SOUTHEAST TOWARDS THE OHIO VALLEY TONIGHT.
THERE IS MUCH UNCERTAINTY IN HOW LONG THE STRATUS CLOUDS MAY LINGER
IN NORTH DAKOTA. THE MODELS ARE SUGGESTING THE STRATUS REMAINING
WELL-ENTRENCHED OVER THE STATE FOR THE MORNING HOURS...THEN BEGIN
ERODING FROM THE SOUTH THIS AFTERNOON AS WINDS SWITCH FROM NORTHWEST
TO SOUTHEAST AFTER THE HIGH AXIS MOVES THROUGH. HOWEVER...CONFIDENCE
IS LOW WHETHER CLOUDS WILL ERODE MUCH. THERE IS SUCH A WIDE SWATH OF
CLOUDS ASSOCIATED WITH THE WESTERN AND SOUTHERN PORTIONS OF THE
ARCTIC AIRMASS/HIGH...THAT AM THINKING ANY EROSION OF THE CLOUDS IN
SOUTHERN NORTH DAKOTA WOULD BE SHORT-LIVED...AND CLOUDS WOULD RETURN
DURING THE EVENING HOURS AS FORECAST LOW LEVEL MOISTURE FIELDS ARE
VERY HIGH IN THE MODELS. EVEN THIS IS SUSPECT...BECAUSE WARM
ADVECTION SHOULD BE TAKING PLACES FROM WEST TO EAST AS THE ARCTIC
HIGH EXITS THE REGION.
ALL OF THE UNCERTAINTY IN CLOUD COVER WILL IMPACT BOTH FORECAST MAX
TEMPERATURES TODAY AND MIN TEMPERATURES TONIGHT. THE LATEST MODEL
CONSENSUS WOULD RESULT IN MAX TEMPERATURES RANGING FROM THE TEENS
NORTH CENTRAL TO THE LOWER 30S SOUTHWEST...AND MINIMUM TEMPERATURES
TONIGHT RANGING FROM AROUND 5 ABOVE IN THE TURTLE MOUNTAINS TO
AROUND 20 IN THE FAR SOUTHWEST.
.LONG TERM...(FRIDAY THROUGH WEDNESDAY)
ISSUED AT 419 AM CST THU NOV 28 2013
THE MAIN HIGHLIGHT IN THE LONG TERM FORECAST PERIOD CONTINUES TO
BE THE POTENTIAL FOR A PROLONGED PERIOD OF SEVERE WINTER WEATHER
FROM SUNDAY THROUGH THE MIDDLE OF NEXT WEEK. WILL STRESS AT THE
GET-GO THAT FORECAST UNCERTAINTY REMAINS HIGH AND CONFIDENCE BELOW
AVERAGE...ESPECIALLY MONDAY-WEDNESDAY.
THE EXTENDED PERIOD BEGINS FRIDAY MORNING WITH RELATIVELY WEAK
NORTHWEST FLOW ALOFT. AN EMBEDDED S/WV WILL BE MOVING EAST-
SOUTHEAST ACROSS NORTHERN SASKATCHEWAN/MANITOBA...WITH AN
ASSOCIATED SFC TROUGH AXIS APPROACHING THE FAR WESTERN DAKOTAS.
EXTENSIVE AREA OF LOW STRATUS CURRENTLY OVER THE REGION THIS
THURSDAY MORNING IS PROJECTED TO STILL HAVE SOME REMNANTS ALONG
TO AHEAD OF THIS BOUNDARY FRIDAY MORNING...SLOWLY ERODING WEST TO
EAST AND ACROSS THE SOUTHERN EXTENT AS THE FRONTAL BOUNDARY MOVES
ACROSS THE WEST AND CENTRAL PORTIONS OF THE STATE AS THE DAY
PROGRESSES. EXPECT A MAINLY DRY FROPA WITH MAINLY A MODERATE TO
HIGH PERCENT OF CLOUD COVER THE MAIN RESULT INTO FRIDAY NIGHT.
CAA FRIDAY NIGHT INTO SATURDAY WITH WEAK HIGH PRESSURE DEVELOPING
ACROSS THE REGION. DESPITE SOME CLOUD COVER...SATURDAY IS SHAPING
UP TO BE AN OVERALL PLEASANT LATE-FALL DAY WITH A WEAK SFC
PRESSURE GRADIENT RESULTING IN LIGHT WINDS AND TEMPERATURES
SEASONABLE AROUND 30 NORTH TO THE LOWER 40S SOUTHWEST. NOT A BAD
DAY TO WRAP UP OUTSIDE HOUSE WORK OR FINISH CHRISTMAS DECORATING
CONSIDERING WHAT IS IN STORE FOR US NEXT WEEK.
UPPER LEVEL LOW PRESSURE CURRENTLY SPINNING OVER ALASKA IS
FORECAST TO PROPAGATE SOUTHEAST ALONG THE BRITISH COLUMBIA COAST
SATURDAY NIGHT INTO SUNDAY NIGHT...POSITIONED OVER THE PACIFIC
NORTHWEST BY MONDAY MORNING. MODELS HAVE TRENDED A TAD MORE
CONSISTENT WITH LEAD S/WV APPROACHING AND MOVING THROUGH THE
NORTHERN PLAINS SUNDAY MORNING - SUNDAY NIGHT...ALONG WITH
INCREASING THERMAL UPGLIDE OVER THE WEST AND CENTRAL PORTIONS OF
THE STATE SUNDAY DAYTIME WITH A LEE SIDE SFC TROUGH TAKING SHAPE
JUST OFF TO OUR WEST OVER THE NORTHERN HIGH PLAINS OF MT/WY. 00Z
BUFFER DATA IS INDICATING THERE MAY BE ENOUGH ABOVE FREEZING MID
LEVEL AIR SUNDAY/SUNDAY NIGHT ACROSS THE SOUTHWEST FOR MIXED
PRECIPITATION WITH SUB-FREEZING SFC TEMPERATURES FORECAST.
ELSEWHERE THE PRECIP TYPE SHOULD BE ALL SNOW. GENERALLY LIGHT QPF
WITH THIS FIRST WAVE OF OVERRUNNING PRECIPITATION.
WILL NOT GET INTO DETAILS MONDAY-WEDNESDAY WITH STILL A WIDE
VARIETY OF SOLUTIONS ON THE EVENTUAL EVOLUTION OF THE PACIFIC
NORTHWEST LOW. THE 00Z GFS REMAINS MUCH MORE PROGRESSIVE AT
FIRST MONDAY AND TUESDAY WITH THE EASTWARD EXTENT OF THE LOW AND
THE LARGE SIZE OF CYCLONIC CIRCULATION...THEN MORPHING INTO A
SPLIT FLOW REGIME TUESDAY NIGHT - WED. THE LAST TWO RUNS (12Z ON
THE 27TH AND 00Z ON THE 28TH) OF THE ECMWF ARE MUCH LESS
PROGRESSIVE...MAINTAINING A CLOSED SYSTEM THROUGH WEDNESDAY NIGHT
OVER THE INTERMOUNTAIN WEST AND NORTHERN U.S. ROCKIES. THE 12Z RUN
MAINTAINED A CLOSED SYSTEM THROUGH THE WORKWEEK...WHILE THE LATEST
00Z RUN OF THE ECMWF NOW DEVELOPS SPLIT FLOW BY THURSDAY. EMBEDDED
ENERGY EJECTING OUT OF THIS FEATURE IMPOSSIBLE AT THIS TIME TO
ACCURATELY TIME OR TRACK SO LEANED ON ALLBLEND GUIDANCE WITH ZERO
EDITS FROM ITS OUTPUT DAYS 5-8. WILL MENTION THAT THE LAST TWO
ECMWF RUNS DO INDICATE HIGH QPF ACROSS SOUTH DAKOTA INTO SOUTHERN
NORTH DAKOTA BEGINNING TUESDAY NIGHT AND ENDING SOMETIME THURSDAY.
WITH THE COLD PROFILE ADVERTISED WOULD SEE SIGNIFICANT SNOW
ACCUMULATIONS BASED ON THESE TWO MODEL OUTPUTS ALONG TO SOUTH OF
I-94. WILL CONTINUE TO MONITOR.
&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z THURSDAY NIGHT)
ISSUED AT 419 AM CST THU NOV 28 2013
LATEST SATELLITE IMAGERY AND SURFACE OBSERVATIONS SHOW MVFR CIGS
ACROSS ALL OF NORTH DAKOTA EARLY THIS MORNING. EXPECT ALL
AERODROMES TO REMAIN MVFR THROUGH SUNRISE. CIGS SHOULD BEGIN TO
IMPROVE TO VFR DURING THE LATE AFTERNOON OR EARLY EVENING HOURS ON
THURSDAY. THERE IS MUCH UNCERTAINTY FOR WHEN/IF/TIMING OF MVFR
CLOUDS SCATTERING OUT DURING THE DAYLIGHT HOURS.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z FRIDAY MORNING)
ISSUED AT 646 AM CST THU NOV 28 2013
LATEST SATELLITE IMAGERY AND SURFACE OBSERVATIONS SHOW MVFR CIGS
ACROSS ALL OF NORTH DAKOTA EARLY THIS MORNING. EXPECT ALL
AERODROMES TO REMAIN MVFR THROUGH SUNRISE. CIGS SHOULD BEGIN TO
IMPROVE TO VFR DURING THE LATE AFTERNOON OR EARLY EVENING HOURS ON
THURSDAY. THERE IS MUCH UNCERTAINTY FOR WHEN/IF/TIMING OF MVFR
CLOUDS SCATTERING OUT DURING THE DAYLIGHT HOURS. AFTER 00Z LOWER
LEVEL CIGS EXPECTED TO REDEVELOP WITH MVFR CIGS AFTER 03Z.
&&
.BIS WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...NH
SHORT TERM...JV
LONG TERM...NH
AVIATION...JV
AREA FORECAST DISCUSSION
NWS GRAND FORKS ND
641 AM CST THU NOV 28 2013
.UPDATE...
ISSUED AT 641 AM CST THU NOV 28 2013
CLOUDS CONTINUE TO BE A CHALLENGE. RAP/HRRR CIG GUIDANCE
INITIALIZES WITH CLEAR SKIES...BUT THEN DEVELOPS LOW CIGS DURING
THE AFTERNOON HOURS (LIKELY CU...LOW CONVECTIVE TEMPS) WHICH GET
TRAPPED UNDER THE RIDGE TONIGHT. RAP 925MB-850MB RH FIELD
ACTUALLY INDICATES THE DRYING THAT IS WORKING THROUGH THE
VALLEY...AND PROBABLY IS CLOSEST TO THE TRUTH. ADJUSTED THE SKY
GRIDS FOR CURRENT OBSERVATIONS AND LATEST RAP 925MB-850MB RH. NO
MAJOR CHANGES YET UNTIL MORE CONFIDENCE CAN BE OBTAINED WITH WHAT
EVER THE CLOUDS WILL DO TODAY.
&&
.SHORT TERM...(TODAY THROUGH FRIDAY)
ISSUED AT 300 AM CST THU NOV 28 2013
NORTHWEST FLOW ALOFT WILL CONTINUE INTO FRIDAY...WITH ANOTHER
SHORTWAVE EXPECTED FRIDAY INTO FRIDAY NIGHT. 00Z MODELS INDICATE
THAT THIS NEXT SHORTWAVE WILL TRACK FURTHER NORTH THAN THE ONE
YESTERDAY...KEEPING ACCUMULATING SNOWFALL OUTSIDE OF THE FA.
FOR TODAY...THE REGION WILL BE BETWEEN SHORTWAVES AS HIGH PRESSURE
BUILDS FROM THE NORTH. THIS WILL LEAVE CLOUD TRENDS AS THE MAIN
CHALLENGE. 09Z SATELLITE IMAGERY SHOWS CLEARING WORKING INTO THE
NORTHERN VALLEY. MODELS ARE STRUGGLING WITH THE CURRENT CLOUD
COVER...ALTHOUGH THE 07Z RAP IS CLOSEST WHEN LOOKING AT THE 925MB-
850MB RH FIELD. THIS MODEL INDICATES THAT CLEARING WILL CONTINUE
TO MOVE DOWN THE VALLEY...WITH CLOUDS DISSIPATING ALONG BOTH
EDGES THROUGH THE DAY. THIS SCENARIO MAKES SOME SENSE WITH THE
HIGH BUILDING INTO THE REGION. HOWEVER...CONVECTIVE TEMPS WILL BE
IN THE TEENS UNTIL LATE AFTERNOON...WHICH COULD LEAD TO
REDEVELOPMENT WITHIN CLEARING AREAS. DID DELAY THE CLEARING...BUT
REMAINED OPTIMISTIC THAT MOST AREAS WILL CLEAR THIS AFTERNOON.
ALSO...CONSIDERING CURRENT CONDITIONS...MENTIONED FLURRIES WITHIN
EXPECTED CLOUDY AREAS.
MIN TEMPS TONIGHT VERY DEPENDENT ON WHETHER OR NOT WE GET RID OF
THE CLOUDS TODAY. IF WE DO CLEAR...THERE WILL LIKELY WILL BE A
QUICK DROP THIS EVENING BEFORE RETURN FLOW KICKS IN AND TEMPS
BECOME STEADY AFTER MIDNIGHT.
.LONG TERM...(FRIDAY NIGHT THROUGH WEDNESDAY)
ISSUED AT 300 AM CST THU NOV 28 2013
FRIDAY NIGHT-SATURDAY NIGHT...HIGH PRESSURE MOVING THROUGH SHOULD
LEAD TO DRY WEATHER. NOT SURE ABOUT CLOUD COVER (CONSIDERING
CURRENT CONDITIONS FOLLOWING A SHORTWAVE). CURRENT THOUGHT IS THAT
SINCE THE FRIDAY SHORTWAVE WILL TRACK FURTHER NORTH THAN THE
CURRENT SYSTEM...SHOULD BE LESS CLOUDS. ALSO...ANTICIPATE A WARMER
AIRMASS.
SUNDAY-WEDNESDAY...DETERMINISTIC MODEL RUNS CONTINUE TO SUGGEST A
MORE ACTIVE PATTERN TAKING SHAPE NEXT WEEK AS AN UPPER WAVE
CURRENTLY ACROSS ALASKA DIVES SOUTHWARD INTO THE WESTERN CONUS
DURING THE FIRST HALF OF NEXT WEEK...WITH ZONAL FLOW TRANSITIONING
TO SOUTHWEST FLOW ALOFT DOWNSTREAM ACROSS THE PLAINS. 00Z MODELS
SUGGEST THE POTENTIAL FOR SOME LIGHT SNOW WITH WARM ADVECTION LATER
SUNDAY INTO MONDAY. BEYOND THIS POINT...CONFIDENCE REGARDING ANY
PARTICULAR DETAILS IS VERY LOW...WITH SIGNIFICANT DIFFERENCES AMONG
MODELS IN HANDLING THE UPPER LONGWAVE TROUGH AND TIMING/PLACEMENT
OF EMBEDDED SHORTWAVE TROUGHS. THE LOW TO MID-LEVEL BAROCLINIC ZONE
WILL REMAIN POSITIONED ACROSS THE NORTHERN PLAINS THROUGH MID-WEEK
BEFORE ADVANCING SOUTHWARD. ANY WAVE EJECTING OUT OF THE BROADER
TROUGH TO THE WEST ALONG THIS BAROCLINIC ZONE WILL NEED TO BE
WATCHED FOR SFC CYCLONE DEVELOPMENT...WITH THE 00Z ECMWF INDICATING
A MORE SIGNIFICANT WAVE FOR THE MIDDLE OF THE WEEK. GIVEN THE VARIED
MODEL SOLUTIONS...CONTINUED WITH BROADBRUSHED SLIGHT/CHANCE POPS
THROUGH MUCH OF THE PERIOD. TEMPS THROUGH MID-WEEK LOOK TO BE
SEASONABLE BEFORE COLDER AIR ARRIVES LATE IN THE WEEK.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z FRIDAY MORNING)
ISSUED AT 641 AM CST THU NOV 28 2013
LOW CONFIDENCE FORECAST FOR TODAY AS GUIDANCE IS PERFORMING POORLY
WITH THE CURRENT SITUATION. THE MOST LIKELY SCENARIO IS THAT MVFR
CIGS WILL REMAIN WEST OF THE VALLEY THROUGH MUCH OF THE
DAY...BREAKING UP BY THIS EVENING. SKY WITHIN THE VALLEY
(KGFK/KFAR) IS CURRENTLY CLEAR...AND SHOULD REMAIN THAT WAY (WITH
A BRIEF PERIOD OF MVFR CU DEVELOPMENT MID-DAY). ANTICIPATE
CLEARING EAST OF THE VALLEY BY EARLY TO MID AFTERNOON. WILL AMEND
THE TAFS IF MORE CONFIDENCE CAN BE OBTAINED.
&&
.FGF WATCHES/WARNINGS/ADVISORIES...
ND...NONE.
MN...NONE.
&&
$$
UPDATE...TG
SHORT TERM...TG
LONG TERM...TG/MAKOWSKI
AVIATION...TG
AREA FORECAST DISCUSSION
NWS GRAND FORKS ND
300 AM CST THU NOV 28 2013
.SHORT TERM...(TODAY THROUGH FRIDAY)
ISSUED AT 300 AM CST THU NOV 28 2013
NORTHWEST FLOW ALOFT WILL CONTINUE INTO FRIDAY...WITH ANOTHER
SHORTWAVE EXPECTED FRIDAY INTO FRIDAY NIGHT. 00Z MODELS INDICATE
THAT THIS NEXT SHORTWAVE WILL TRACK FURTHER NORTH THAN THE ONE
YESTERDAY...KEEPING ACCUMULATING SNOWFALL OUTSIDE OF THE FA.
FOR TODAY...THE REGION WILL BE BETWEEN SHORTWAVES AS HIGH PRESSURE
BUILDS FROM THE NORTH. THIS WILL LEAVE CLOUD TRENDS AS THE MAIN
CHALLENGE. 09Z SATELLITE IMAGERY SHOWS CLEARING WORKING INTO THE
NORTHERN VALLEY. MODELS ARE STRUGGLING WITH THE CURRENT CLOUD
COVER...ALTHOUGH THE 07Z RAP IS CLOSEST WHEN LOOKING AT THE 925MB-
850MB RH FIELD. THIS MODEL INDICATES THAT CLEARING WILL CONTINUE
TO MOVE DOWN THE VALLEY...WITH CLOUDS DISSIPATING ALONG BOTH
EDGES THROUGH THE DAY. THIS SCENARIO MAKES SOME SENSE WITH THE
HIGH BUILDING INTO THE REGION. HOWEVER...CONVECTIVE TEMPS WILL BE
IN THE TEENS UNTIL LATE AFTERNOON...WHICH COULD LEAD TO
REDEVELOPMENT WITHIN CLEARING AREAS. DID DELAY THE CLEARING...BUT
REMAINED OPTIMISTIC THAT MOST AREAS WILL CLEAR THIS AFTERNOON.
ALSO...CONSIDERING CURRENT CONDITIONS...MENTIONED FLURRIES WITHIN
EXPECTED CLOUDY AREAS.
MIN TEMPS TONIGHT VERY DEPENDENT ON WHETHER OR NOT WE GET RID OF
THE CLOUDS TODAY. IF WE DO CLEAR...THERE WILL LIKELY WILL BE A
QUICK DROP THIS EVENING BEFORE RETURN FLOW KICKS IN AND TEMPS
BECOME STEADY AFTER MIDNIGHT.
.LONG TERM...(FRIDAY NIGHT THROUGH WEDNESDAY)
ISSUED AT 300 AM CST THU NOV 28 2013
FRIDAY NIGHT-SATURDAY NIGHT...HIGH PRESSURE MOVING THROUGH SHOULD
LEAD TO DRY WEATHER. NOT SURE ABOUT CLOUD COVER (CONSIDERING
CURRENT CONDITIONS FOLLOWING A SHORTWAVE). CURRENT THOUGHT IS THAT
SINCE THE FRIDAY SHORTWAVE WILL TRACK FURTHER NORTH THAN THE
CURRENT SYSTEM...SHOULD BE LESS CLOUDS. ALSO...ANTICIPATE A WARMER
AIRMASS.
SUNDAY-WEDNESDAY...DETERMINISTIC MODEL RUNS CONTINUE TO SUGGEST A
MORE ACTIVE PATTERN TAKING SHAPE NEXT WEEK AS AN UPPER WAVE
CURRENTLY ACROSS ALASKA DIVES SOUTHWARD INTO THE WESTERN CONUS
DURING THE FIRST HALF OF NEXT WEEK...WITH ZONAL FLOW TRANSITIONING
TO SOUTHWEST FLOW ALOFT DOWNSTREAM ACROSS THE PLAINS. 00Z MODELS
SUGGEST THE POTENTIAL FOR SOME LIGHT SNOW WITH WARM ADVECTION LATER
SUNDAY INTO MONDAY. BEYOND THIS POINT...CONFIDENCE REGARDING ANY
PARTICULAR DETAILS IS VERY LOW...WITH SIGNIFICANT DIFFERENCES AMONG
MODELS IN HANDLING THE UPPER LONGWAVE TROUGH AND TIMING/PLACEMENT
OF EMBEDDED SHORTWAVE TROUGHS. THE LOW TO MID-LEVEL BAROCLINIC ZONE
WILL REMAIN POSITIONED ACROSS THE NORTHERN PLAINS THROUGH MID-WEEK
BEFORE ADVANCING SOUTHWARD. ANY WAVE EJECTING OUT OF THE BROADER
TROUGH TO THE WEST ALONG THIS BAROCLINIC ZONE WILL NEED TO BE
WATCHED FOR SFC CYCLONE DEVELOPMENT...WITH THE 00Z ECMWF INDICATING
A MORE SIGNIFICANT WAVE FOR THE MIDDLE OF THE WEEK. GIVEN THE VARIED
MODEL SOLUTIONS...CONTINUED WITH BROADBRUSHED SLIGHT/CHANCE POPS
THROUGH MUCH OF THE PERIOD. TEMPS THROUGH MID-WEEK LOOK TO BE
SEASONABLE BEFORE COLDER AIR ARRIVES LATE IN THE WEEK.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z THURSDAY NIGHT)
ISSUED AT 1148 PM CST WED NOV 27 2013
MVFR CIGS CONTINUE TO REMAIN WEST OF THE RED RIVER VALLEY AND
CONTINUE TO MOVE SOUTH FROM WEST AND CENTRAL ND. WILL GENERALLY KEEP
VFR CIGS ACROSS THE AREA EXCEPT FOR THE EAST/NORTHEAST ZONES. LIGHT
SNOW SHOULD LOWER CIGS AND VISIBILITIES IN THE NORTHEAST ZONES. LOW
LEVEL RH GETS TO BE A THIN LAYER BY THU AFTERNOON. WILL SCATTER
CLOUDS OUT AROUND THE NOON HOUR.
&&
.FGF WATCHES/WARNINGS/ADVISORIES...
ND...NONE.
MN...NONE.
&&
$$
SHORT TERM...TG
LONG TERM...TG/MAKOWSKI
AVIATION...HOPPES
AREA FORECAST DISCUSSION
NWS BISMARCK ND
1236 AM CST THU NOV 28 2013
.UPDATE...
ISSUED AT 1236 AM CST THU NOV 28 2013
STRATUS CLOUDS COVERED ALL BUT THE EXTREME SOUTHWESTERN CORNER OF
THE STATE...AND THE TREND IN SATELLITE LOOP INDICATES THE SOUTHWEST
CORNER SHOULD SOON BE CLOUDY. THE LOW PRESSURE CENTER ASSOCIATED
WITH THE COLD FRONT THAT MOVED THROUGH THE STATE WEDNESDAY WAS WELL
TO THE SOUTHEAST...FROM MINNESOTA/IOWA TO SOUTHERN NEBRASKA AND
NORTHWEST WINDS CONTINUED ACROSS NORTH DAKOTA. THE ARCTIC HIGH WAS
CENTERED OVER NORTHERN MANITOBA WITH ITS AXIS EXTENDING
SOUTHWESTWARD ACROSS SOUTHERN SASKATCHEWAN AND INTO THE
MONTANA/NORTH DAKOTA BORDER. SKIES SHOULD REMAIN CLOUDY FOR THE REST
OF THE NIGHTTIME HOURS...BUT THERE IS UNCERTAINTY AS TO
WHEN/IF/WHERE THE LOW CLOUDS WILL SCATTER DURING THE DAYLIGHT HOURS
ON THANKSGIVING DAY.
ONLY ADJUSTMENTS WERE TO THE HOURLY TEMPERATURE/DEWPOINT TRENDS.
OTHERWISE CURRENT FORECAST ON TRACK.
UPDATE ISSUED AT 924 PM CST WED NOV 27 2013
LATEST SATELLITE IMAGERY AND SURFACE OBSERVATIONS CONTINUE TO SHOW
WESTERN AND CENTRAL NORTH DAKOTA INUNDATED WITH STRATUS. ISOLATED
FLURRIES CONTINUE IN THE NORTH. ONLY ADJUSTMENT WAS TO RAISE
OVERNIGHT TEMPERATURES BETWEEN 3 AND 5 DEGREES DUE TO THE CLOUDS
AND MIXED BOUNDARY LAYER/BRISK WINDS. LATEST NAM AND RAP13 SHOWS
THE STRATUS CONTINUING THROUGH 18Z THURSDAY...AND POSSIBLY INTO
THE AFTERNOON.
UPDATE ISSUED AT 556 PM CST WED NOV 27 2013
MAIN UPDATE THIS EVENING WAS TO INCREASE SKY GRIDS TO 100 PERCENT
OVER MOST OF WESTERN AND CENTRAL NORTH DAKOTA. LATEST FOG/STRATUS
LOOP IN CONJUNCTION WITH THE RAP13 AND HRRR 925MB-H85 RH FIELD...ARE
VERIFYING WELL AND ARE IN GOOD AGREEMENT TONIGHT. THE STRATUS WILL
MAKE IT TO THE SOUTHERN BORDER IN THE NEXT FEW HOURS AS WELL AS
INTO THE JAMES RIVER VALLEY. EXPECT OVERCAST CONDITIONS WITH ISOLATED
FLURRIES TONIGHT INTO MID MORNING THURSDAY BEFORE SKY IMPROVEMENTS
BEGIN. REST OF FORECAST IS ON TRACK.
&&
.SHORT TERM...(THIS EVENING THROUGH THURSDAY)
ISSUED AT 352 PM CST WED NOV 27 2013
THE TEMPERATURE ROLLER COASTER WILL CONTINUE TONIGHT AND THURSDAY
AS ANOTHER SHOT OF COLD CANADIAN AIR PUSHES SOUTH INTO NORTH
DAKOTA. LOW STRATUS HAS ADVANCED INTO FAR NORTHWEST ND DURING THE
EARLY AFTERNOON...AND WILL CONTINUE A SOUTHWARD PUSH...ACCOMPANIED
BY A FEW FLURRIES. EXPECT ANOTHER NIGHT OF LOWS IN THE SINGLE
DIGITS TO TEENS SOUTHWEST.
ON THANKSGIVING DAY...HIGH PRESSURE WILL DRIFT INTO EASTERN
NORTH DAKOTA ON THURSDAY...SETTING UP ANOTHER NE-SW TEMPERATURE
GRADIENT. HIGHS ARE FORECAST IN THE MID TEENS NEAR THE TURTLE
MOUNTAINS...LOW TO MID 20S NEAR BISMARCK/MANDAN...AND NEAR 30 AT BOWMAN.
.LONG TERM...(THURSDAY NIGHT THROUGH WEDNESDAY)
ISSUED AT 352 PM CST WED NOV 27 2013
POTENTIAL MAJOR WINTER STORM NEXT WEEK.
THE MAIN FOCUS THROUGH THE EXTENDED PERIOD IS ON A POTENTIAL
WINTER STORM THAT MAY IMPACT THE REGION SUNDAY THROUGH THURSDAY.
AT THIS TIME THERE IS A LOT OF UNCERTAINTY AS TO
TIMING...PLACEMENT AND AMOUNTS. MODEL RUNS HAVE SLOWLY COME INTO
BETTER AGREEMENT OVER THE PAST RUN...BUT THERE ARE STILL LARGE
DISCREPANCIES THAT NEED TO BE RESOLVED BEFORE CONFIDENCE CLIMBS
HIGH ENOUGH TO WARRANT ANY THOUGHT OF WINTER WEATHER HEADLINES.
THE 12 UTC HAS THE POLAR AND SUBTROPICAL JETS PHASING TOGETHER LATE
NEXT WEEK AS A VERY POTENT LONGWAVE TROUGH DIGS SOUTH ACROSS THE
MOUNTAIN WEST. THIS WOULD SET UP VERY STRONG CYCLOGENESIS ACROSS
THE PLAINS. THE ECMWF IS STRONGER AND DEEPER WITH THIS TROUGH AND
CYCLOGENESIS AND THEREFORE FURTHER SOUTH AND SLIGHTLY SLOWER THAN
THE GFS. THE 12 UTC GFS MAINTAINS SPLIT FLOW UNTIL THE VERY END OF
NEXT WEEK AND DEVELOPS MORE OF A PROGRESSIVE OPEN WAVE. THIS WOULD
TEND TO FAVOR A QUICKER AND FURTHER NORTH SOLUTION.
ONE THING THAT IS MORE CERTAIN IS THE INTRUSION OF COLD AIR. A
VERY COLD AIRMASS IS SETTING UP ACROSS EASTERN SIBERIA AND IS
PROGGED TO ENTER EASTERN ALASKA AND FROM THERE MAKE A BEELINE
TOWARD THE CENTRAL CONTINENTAL USA. THIS COULD POTENTIALLY BE THE
COLDEST AIR WE HAVE SEEN YET WITH 850MB TEMPS AROUND -25.
UNTIL LATE SUNDAY TEMPERATURES SHOULD BE MILD AND AND PRECIP
CHANCES MINIMAL.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z THURSDAY NIGHT)
ISSUED AT 1236 AM CST THU NOV 28 2013
LATEST SATELLITE IMAGERY AND SURFACE OBSERVATIONS SHOW MVFR CIGS
ACROSS NEARLY ALL OF NORTH DAKOTA EARLY THIS MORNING. EXPECT ALL
AERODROMES TO REMAIN MVFR THROUGH SUNRISE. CIGS SHOULD BEGIN TO
IMPROVE TO VFR DURING THE LATE AFTERNOON OR EARLY EVENING HOURS ON
THURSDAY. THERE IS MUCH UNCERTAINTY FOR WHEN/IF/TIMING OF MVFR
CLOUDS SCATTERING OUT DURING THE DAYLIGHT HOURS.
&&
.BIS WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...JV
SHORT TERM...RK
LONG TERM...AJ
AVIATION...JV
AREA FORECAST DISCUSSION
NWS SIOUX FALLS SD
1150 AM CST THU NOV 28 2013
.UPDATE...
ISSUED AT 949 AM CST THU NOV 28 2013
CLOUDS ARE PROVIDING THE GREATEST CHALLENGE FOR THE SHORT TERM
TODAY. FAIRLY EXTENSIVE CLOUDS PRESENT EARLY THIS MORNING HAVE
DIMINISHED IN COVERAGE EAST...BUT ARE FAIRLY SOLID FOR THE TIME
WEST. BASED ON KABR/KBIS MORNING RAOBS...THESE CLOUDS ARE FAIRLY
SHALLOW...BUT IMPRESSIVELY TRAPPED BELOW INVERSION...MAKING THE
DISSIPATION LIKELY TO BE A RESULT OF DRYING AND LIMITED HEATING
BELOW INVERSION AS WELL AS AN ADVECTIVE COMPONENT. RAP ON THE RIGHT
TRACK...BUT TOO PESSIMISTIC TOWARD I 29 CORRIDOR. AT THIS TIME...
CLOUDS LOOK TO BE FAIRLY TOUGH TO SHAKE IN THE WEST/SOUTHWEST CWA
WHILE THOSE AREAS IN ADVANCE OF THE LOW LEVEL RIDGE AXIS FROM
AROUND I29 EASTWARD ARE CERTAIN TO FIND A MIX OF CLOUDS AND SUN
THROUGH MIDDAY AND THEN TRENDING TOWARD MORE SUN. BASED ON TEMPS
ON CLOUD BEARING LEVEL AS WELL AS UPSTREAM OBSERVATIONS...HAVE
ADDED IN A FEW FLURRIES TO AREAS AS FAR SOUTH AS AROUND KFSD...BUT
EXPECT STRONGER COVERAGE OF LOW REFLECTIVITIES ON KABR RADAR TO
DWINDLE SOMEWHAT WITH INCREASING DISTANCE FROM WEAK TERRAIN
SUPPORT. EARLIER FLURRIES IN SW MN COULD HAVE IMPACTED SOMEWHAT
MORE RAPID DISSIPATION IN CLOUDS...AND MAY ALSO INFLUENCE THE
CLEARING TREND. TEMPS ALSO CHALLENGING WITH CONTINUED LOW LEVEL
COLD AIR ADVECTION...BUT TEMPS ALREADY REACHING INDICATED MIXING
POTENTIAL UNDER CLOUDY AREAS BY MID MORNING. PROBABLY NOT MUCH
ROOM TO WARM MORE THAN A FEW DEGREES ANYWHERE TODAY...MOST SO IN
AREAS WITH SUNSHINE TO THE EAST. UPDATES OUT.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 520 AM CST THU NOV 28 2013
CURRENT SURFACE ANALYSIS SHOWS THE FRONTAL BOUNDARY HAVING PUSHED
THROUGH OUR CWA EARLY THIS MORNING...WITH AN AREA OF STRATUS
STREAMING INTO OUR WESTERN CWA BEHIND THE EXITING SYSTEM. THE
SURFACE RIDGE AXIS PRESENTLY LOCATED THROUGH THE WESTERN PORTIONS OF
THE DAKOTA WILL SLIDE TO THE SOUTH AND EAST TODAY...AND WITH DRYING
AND SUBSIDENCE LOOKING FOR THE LOW CLOUDS TO THIN OUT ACROSS THE
AREA BY LATE MORNING OR EARLY AFTERNOON. OTHERWISE...IT WILL BE
BREEZY DURING THE EARLY PART OF THE DAY...ESPECIALLY IN THE
EAST...WITH COLD AIR ADVECTION AND A DECENT GRADIENT ACROSS THE
AREA...THEN TAPERING DOWN IN THE AFTERNOON AS HIGH PRESSURE BUILDS
IN AND THE GRADIENT RELAXES AND ML WINDS DECREASE. THERMAL PROFILES
DO COOL A BIT TODAY...THOUGH NOTHING TOO EXTREME WITH HIGHS STILL
MAKING IT INTO THE MID 20S TO LOWER 30S FROM NORTHEAST TO SOUTHWEST
RESPECTIVELY.
THE HIGH PRESSURE MOVES QUICKLY TO THE EAST TONIGHT...AND WITH THAT
WINDS WILL TRANSITION TO SOUTHEASTERLY AND PICK UP LATER AT NIGHT.
IT WILL STILL BE A COLD NIGHT WITH LOWS IN THE UPPER SINGLE DIGITS
TO TEENS...WITH TEMPS STEADYING OUT OR RISING SOME LATE AT NIGHT AS
THE WINDS INCREASE.
.LONG TERM...(FRIDAY THROUGH WEDNESDAY)
ISSUED AT 520 AM CST THU NOV 28 2013
POTENT PACIFIC LOW DIVES INTO THE PACIFIC NORTHWEST FRIDAY AND
SATURDAY...SHIFTING THE INTERMOUNTAIN WEST RIDGING ITO THE PLAINS
STATES. A STRONG PUSH OF WARM AIR ADVECTION AND BREEZY SOUTHERLY
WINDS WILL BRING MILDER TEMPERATURES ON FRIDAY DESPITE SOME PASSING
MID AND HIGH CLOUDS FILTERING THE SUNSHINE. HIGHS WILL WARM TO
SLIGHTLY ABOVE NORMAL READINGS IN THE LOW 30S EAST TO THE MID 40S
WEST. A WEAK FRONT SAGS ACROSS THE FORECAST AREA FRIDAY NIGHT
THROUGH SATURDAY MORNING...BUT WITHOUT MOISTURE OR A REAL COLD AIR
PUSH BEHIND IT...CONDITIONS WILL REMAIN DRY AND MILD WITH HIGHS
MIXING INTO THE UPPER 30S TO MID 40S.
MUCH GREATER UNCERTAINTY SHOWS UP EARLY NEXT WEEK AS THE PACIFIC
TROUGH STRENGTHENS AND MOVES INTO THE NORTHERN ROCKIES. MODELS STILL
SHOWING SIGNIFICANT DIFFERENCES IN THE STRENGTH...TIMING AND TRACK
OF THE UPPER LOW. THE GFS FOLLOWS A MORE NORTHERLY TRACK WHILE THE
ECMWF IS SLOWER AND FURTHER SOUTH. FINALLY...THE CANADIAN DEPICTS A
MUCH WEAKER SYSTEM OVERALL WHICH GIVEN THE ENERGETIC NATURE OF THIS
SYSTEM SEEMS THE LEAST LIKELY.
INITIAL SHORTWAVE AHEAD OF THE MAIN SYSTEM SLIDES SOUTHEAST ACROSS
THE REGION AROUND THE SUNDAY NIGHT/MONDAY TIME FRAME. WITH THE GFS
RAPIDLY AMPLIFYING THE PAC NW TROUGH AND UPPER RIDGE AHEAD OF
IT...THIS WAVE IS WEAKER AND FASTER MOVING THAN THE ECMWF WHICH
DEVELOPS AN INVERTED TROUGH FEATURE OVER THE NORTHERN AND CENTRAL
PLAINS AND KEEPS IT IN THE PICTURE WELL INTO TUESDAY. SIGNIFICANT
DIFFERENCES IN TEMPERATURE PROFILES ALSO MAKE PRECIPITATION TYPES
DIFFICULT TO PINPOINT. TEMPERATURES LOOK TO REMAIN SEASONALLY MILD
THROUGH WEDNESDAY WITH MUCH COOLER READINGS ARRIVING LATE IN THE
WEEK. FOR NOW WILL KEEP MENTION OF BOTH RAIN AND SNOW. NOT MUCH
CONFIDENCE IN THE TIMING OF THE PRECIPITATION BUT CHANCES DO APPEAR
TO IMPROVE AS WE MOVE TOWARDS MID WEEK AS THE MAIN PACIFIC TROUGH
ADVANCES TOWARDS THE REGION. FOR NOW DID NOT ALTER THE ALLBLEND POPS
OR TEMPS MUCH GIVEN SUCH UNCERTAINTY.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z FRIDAY AFTERNOON)
ISSUED AT 1149 AM CST THU NOV 28 2013
MVFR CEILINGS WILL CONTINUE ACROSS MUCH OF THE AREA EARLY THIS
AFTERNOON... BUT SHOULD GRADUALLY SEE COVERAGE BEGIN TO FAVOR
AREAS WEST OF THE JAMES RIVER VALLEY AFTER 21Z. REMAINDER OF THE
PERIOD SHOULD BE VFR...WITH EXCEPTION OF THOSE CEILINGS HANGING
UP IN THE FAR WEST. AT THIS POINT...IT IS ANTICIPATED THAT MOST OF
THE CEILINGS WILL DISSIPATE BEFORE RETURNING EASTWARD EARLY
FRIDAY...BUT COULD HAVE TO WATCH KHON FOR SOME MVFR CLOUDS AGAIN
BY AROUND 15Z.
&&
.FSD WATCHES/WARNINGS/ADVISORIES...
SD...NONE.
MN...NONE.
IA...NONE.
NE...NONE.
&&
$$
UPDATE...CHAPMAN
SHORT TERM...
LONG TERM...JM
AVIATION...CHAPMAN
AREA FORECAST DISCUSSION...UPDATED
NWS ABERDEEN SD
1123 AM CST THU NOV 28 2013
.UPDATE...
SEE UPDATED AVIATION DISCUSSION BELOW.
THE MAIN FORECAST CHANGES THIS MORNING REVOLVE AROUND THE STRATUS
DECK THAT HAS SPREAD OVER THE REGION. MODELS ARE MUCH TO
OPTIMISTIC IN ERODING THE CLOUD DECK...SO ADJUSTED THE SKY GRIDS TO
KEEP THE WESTERN HALF OF THE CWA UNDER CLOUD COVER MUCH LONGER
THAN ORIGINALLY ANTICIPATED. ALSO EXTENDED THE FLURRIES MENTION
AS SEVERAL OBS HAVE REPORTED VERY LIGHT SNOW THIS MORNING. OVERALL
THE OTHER FORECAST FIELDS SEEM TO BE ON TRACK...TEMPERATURES WILL
REMAIN PRETTY STEADY THROUGH THE DAY...AND THE INHERITED FORECAST
TREND SEEMS TO BE REFLECTING THIS WELL.
&&
.PREVIOUS DISCUSSION...
.SHORT TERM...TODAY THROUGH SATURDAY
AN EXTENSIVE STRATUS DECK OVER THE REGION IS KEEPING TEMPERATURES
RELATIVELY MILD WITH CURRENT READINGS IN THE MID 20S. BASED ON THE
PAST FEW RUNS OF THE RUC...IT SEEMS UNLIKELY THIS STRATUS DECK
WILL DISSIPATE ANYTIME SOON. WOULD NOT BE TOO SURPRISED IF THESE
CLOUDS HANG AROUND THROUGH THIS AFTERNOON BEFORE DRIER AIR AT 925
MB MOVES IN FROM THE SOUTHWEST. OF COURSE THESE CLOUDS WILL MAKE
FORECASTING HIGH TEMPERATURES RATHER DIFFICULT. HAVE RELIED UPON
THE RUC MODEL WHICH SHOWS A SLIGHT COOL DOWN AROUND SUNRISE...THEN
A SLIGHT INCREASE BY 21Z.
HIGH PRESSURE SHIFTS EAST OF THE REGION TONIGHT...ALLOWING WAA TO
SPREAD ACROSS THE WESTERN CWA WHERE TEMPERATURES SHOULD BECOME
STEADY OR SLOWLY RISE AFTER MIDNIGHT. ANOTHER WEAK LOW PRESSURE
SYSTEM PASSING ACROSS THE REGION ON FRIDAY WILL BRING WARM
TEMPERATURES BACK INTO THE AREA. TEMPS AT 925/850 MB ARE PROJECTED
TO RANGE AROUND NORMAL...WHICH WHEN COMBINED WITH DECENT MIXING
WINDS SHOULD EQUAL HIGHS IN THE MID 30S...TO THE MID 40S. WOULD
NOT BE TOO SURPRISED IF HIGH TEMPERATURES END UP BEING WARMER.
SLIGHTLY COOLER LOW LEVEL TEMPERATURES ALONG WITH WEAK CAA ON
SATURDAY WILL RESULT IN HIGHS IN THE LOW TO MID 30S.
.LONG TERM...SATURDAY NIGHT THROUGH WEDNESDAY
LATEST MODEL RUNS CONTINUE TO FORECAST A MAJOR PATTERN SHIFT
DURING THE LONG TERM. HOWEVER THE DETAILS REMAIN SKETCHY AS EACH
MODEL HAS ITS OWN IDEA ON HOW TO HANDLE ENERGY WITHIN THE
DEVELOPING MID LEVEL TROF AND THAT TROFS EVOLUTION THROUGH THE
MIDDLE OF NEXT WEEK. THE ECMWF IS BY FAR THE MOST AGGRESSIVE IN
SETTING UP A BAROCLINIC ZONE ACROSS THE REGION AND CRANKS OUT
COPIOUS AMOUNTS OF PCPN FROM TUESDAY THROUGH THURSDAY. THE GFS IS
MORE PROGRESSIVE AND FEATURES A MORE POSITIVE TILT MID LEVEL TROF
OVER THE WESTERN/CENTRAL CONUS LEADING TO A LESS INTENSE
BAROCLINIC ZONE OVER THE NORTHERN PLAINS. THE LAST COUPLE RUNS OF
THE ECMWF HAVE BEEN CONSISTENTLY SLOWER AND WETTER VS THE GFS. BUT
IT SEEMS OVERLY WET. NONETHELESS WILL BE AN INTERESTING MIDDLE OF
NEXT WEEK WEATHER-WISE WITH A MIXED BAG OF PCPN EXPECTED NO MATTER
WHICH MODEL YOU LIKE. TEMPERATURES ARE EXPECTED TO BE ABOVE NORMAL
FOR THE FIRST PART OF THE PERIOD...BUT THEN TRANSITION TOWARD
NORMAL AS COLDER AIR INVADES FROM CANADA TOWARD MID TO LATE WEEK.
&&
.AVIATION...
18Z TAFS FOR THE KABR...KATY...KPIR AND KMBG TERMINALS
MVFR CIGS WILL PREVAIL THIS AFTERNOON AND INTO THE OVERNIGHT
HOURS ACROSS THE WESTERN HALF OF THE CWA...INCLUDING KPIR AND
KMBG. KABR AND KATY LOOK TO BE RIGHT ON THE EDGE OF THESE
CIGS...SO WILL BE IN AND OUT OF THE MVFR CIGS. FROM LATE TONIGHT
AND THROUGH THE MORNING HOURS ON FRIDAY...VFR CONDITIONS WILL
PREVAIL.
&&
.ABR WATCHES/WARNINGS/ADVISORIES...
SD...NONE.
MN...NONE.
&&
$$
UPDATE...SERR
SHORT TERM...SD
LONG TERM...TDK
AVIATION...PARKIN
WEATHER.GOV/ABERDEEN
AREA FORECAST DISCUSSION...UPDATED
NWS ABERDEEN SD
1035 AM CST THU NOV 28 2013
.UPDATE...
THE MAIN FORECAST CHANGES THIS MORNING REVOLVE AROUND THE STRATUS
DECK THAT HAS SPREAD OVER THE REGION. MODELS ARE MUCH TO
OPTIMISTIC IN ERODING THE CLOUD DECK...SO ADJUSTED THE SKY GRIDS TO
KEEP THE WESTERN HALF OF THE CWA UNDER CLOUD COVER MUCH LONGER
THAN ORIGINALLY ANTICIPATED. ALSO EXTENDED THE FLURRIES MENTION
AS SEVERAL OBS HAVE REPORTED VERY LIGHT SNOW THIS MORNING. OVERALL
THE OTHER FORECAST FIELDS SEEM TO BE ON TRACK...TEMPERATURES WILL
REMAIN PRETTY STEADY THROUGH THE DAY...AND THE INHERITED FORECAST
TREND SEEMS TO BE REFLECTING THIS WELL.
&&
.PREVIOUS DISCUSSION...
.SHORT TERM...TODAY THROUGH SATURDAY
AN EXTENSIVE STRATUS DECK OVER THE REGION IS KEEPING TEMPERATURES
RELATIVELY MILD WITH CURRENT READINGS IN THE MID 20S. BASED ON THE
PAST FEW RUNS OF THE RUC...IT SEEMS UNLIKELY THIS STRATUS DECK
WILL DISSIPATE ANYTIME SOON. WOULD NOT BE TOO SURPRISED IF THESE
CLOUDS HANG AROUND THROUGH THIS AFTERNOON BEFORE DRIER AIR AT 925
MB MOVES IN FROM THE SOUTHWEST. OF COURSE THESE CLOUDS WILL MAKE
FORECASTING HIGH TEMPERATURES RATHER DIFFICULT. HAVE RELIED UPON
THE RUC MODEL WHICH SHOWS A SLIGHT COOL DOWN AROUND SUNRISE...THEN
A SLIGHT INCREASE BY 21Z.
HIGH PRESSURE SHIFTS EAST OF THE REGION TONIGHT...ALLOWING WAA TO
SPREAD ACROSS THE WESTERN CWA WHERE TEMPERATURES SHOULD BECOME
STEADY OR SLOWLY RISE AFTER MIDNIGHT. ANOTHER WEAK LOW PRESSURE
SYSTEM PASSING ACROSS THE REGION ON FRIDAY WILL BRING WARM
TEMPERATURES BACK INTO THE AREA. TEMPS AT 925/850 MB ARE PROJECTED
TO RANGE AROUND NORMAL...WHICH WHEN COMBINED WITH DECENT MIXING
WINDS SHOULD EQUAL HIGHS IN THE MID 30S...TO THE MID 40S. WOULD
NOT BE TOO SURPRISED IF HIGH TEMPERATURES END UP BEING WARMER.
SLIGHTLY COOLER LOW LEVEL TEMPERATURES ALONG WITH WEAK CAA ON
SATURDAY WILL RESULT IN HIGHS IN THE LOW TO MID 30S.
.LONG TERM...SATURDAY NIGHT THROUGH WEDNESDAY
LATEST MODEL RUNS CONTINUE TO FORECAST A MAJOR PATTERN SHIFT
DURING THE LONG TERM. HOWEVER THE DETAILS REMAIN SKETCHY AS EACH
MODEL HAS ITS OWN IDEA ON HOW TO HANDLE ENERGY WITHIN THE
DEVELOPING MID LEVEL TROF AND THAT TROFS EVOLUTION THROUGH THE
MIDDLE OF NEXT WEEK. THE ECMWF IS BY FAR THE MOST AGGRESSIVE IN
SETTING UP A BAROCLINIC ZONE ACROSS THE REGION AND CRANKS OUT
COPIOUS AMOUNTS OF PCPN FROM TUESDAY THROUGH THURSDAY. THE GFS IS
MORE PROGRESSIVE AND FEATURES A MORE POSITIVE TILT MID LEVEL TROF
OVER THE WESTERN/CENTRAL CONUS LEADING TO A LESS INTENSE
BAROCLINIC ZONE OVER THE NORTHERN PLAINS. THE LAST COUPLE RUNS OF
THE ECMWF HAVE BEEN CONSISTENTLY SLOWER AND WETTER VS THE GFS. BUT
IT SEEMS OVERLY WET. NONETHELESS WILL BE AN INTERESTING MIDDLE OF
NEXT WEEK WEATHER-WISE WITH A MIXED BAG OF PCPN EXPECTED NO MATTER
WHICH MODEL YOU LIKE. TEMPERATURES ARE EXPECTED TO BE ABOVE NORMAL
FOR THE FIRST PART OF THE PERIOD...BUT THEN TRANSITION TOWARD
NORMAL AS COLDER AIR INVADES FROM CANADA TOWARD MID TO LATE WEEK.
&&
.AVIATION...
12Z TAFS FOR THE KABR...KATY...KPIR AND KMBG TERMINALS
MVFR CIGS ARE EXPECTED TO PERSIST AT LEAST INTO THE AFTERNOON FOR MOST
TERMINALS. MOST AREAS SHOULD BECOME VFR BY EVENING.
&&
.ABR WATCHES/WARNINGS/ADVISORIES...
SD...NONE.
MN...NONE.
&&
$$
UPDATE...SERR
SHORT TERM...SD
LONG TERM...TDK
AVIATION...TDK
WEATHER.GOV/ABERDEEN
AREA FORECAST DISCUSSION
NWS SIOUX FALLS SD
949 AM CST THU NOV 28 2013
.UPDATE...
ISSUED AT 949 AM CST THU NOV 28 2013
CLOUDS ARE PROVIDING THE GREATEST CHALLENGE FOR THE SHORT TERM
TODAY. FAIRLY EXTENSIVE CLOUDS PRESENT EARLY THIS MORNING HAVE
DIMINISHED IN COVERAGE EAST...BUT ARE FAIRLY SOLID FOR THE TIME
WEST. BASED ON KABR/KBIS MORNING RAOBS...THESE CLOUDS ARE FAIRLY
SHALLOW...BUT IMPRESSIVELY TRAPPED BELOW INVERSION...MAKING THE
DISSIPATION LIKELY TO BE A RESULT OF DRYING AND LIMITED HEATING
BELOW INVERSION AS WELL AS AN ADVECTIVE COMPONENT. RAP ON THE RIGHT
TRACK...BUT TOO PESSIMISTIC TOWARD I 29 CORRIDOR. AT THIS TIME...
CLOUDS LOOK TO BE FAIRLY TOUGH TO SHAKE IN THE WEST/SOUTHWEST CWA
WHILE THOSE AREAS IN ADVANCE OF THE LOW LEVEL RIDGE AXIS FROM
AROUND I29 EASTWARD ARE CERTAIN TO FIND A MIX OF CLOUDS AND SUN
THROUGH MIDDAY AND THEN TRENDING TOWARD MORE SUN. BASED ON TEMPS
ON CLOUD BEARING LEVEL AS WELL AS UPSTREAM OBSERVATIONS...HAVE
ADDED IN A FEW FLURRIES TO AREAS AS FAR SOUTH AS AROUND KFSD...BUT
EXPECT STRONGER COVERAGE OF LOW REFLECTIVITIES ON KABR RADAR TO
DWINDLE SOMEWHAT WITH INCREASING DISTANCE FROM WEAK TERRAIN
SUPPORT. EARLIER FLURRIES IN SW MN COULD HAVE IMPACTED SOMEWHAT
MORE RAPID DISSIPATION IN CLOUDS...AND MAY ALSO INFLUENCE THE
CLEARING TREND. TEMPS ALSO CHALLENGING WITH CONTINUED LOW LEVEL
COLD AIR ADVECTION...BUT TEMPS ALREADY REACHING INDICATED MIXING
POTENTIAL UNDER CLOUDY AREAS BY MID MORNING. PROBABLY NOT MUCH
ROOM TO WARM MORE THAN A FEW DEGREES ANYWHERE TODAY...MOST SO IN
AREAS WITH SUNSHINE TO THE EAST. UPDATES OUT.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 520 AM CST THU NOV 28 2013
CURRENT SURFACE ANALYSIS SHOWS THE FRONTAL BOUNDARY HAVING PUSHED
THROUGH OUR CWA EARLY THIS MORNING...WITH AN AREA OF STRATUS
STREAMING INTO OUR WESTERN CWA BEHIND THE EXITING SYSTEM. THE
SURFACE RIDGE AXIS PRESENTLY LOCATED THROUGH THE WESTERN PORTIONS OF
THE DAKOTA WILL SLIDE TO THE SOUTH AND EAST TODAY...AND WITH DRYING
AND SUBSIDENCE LOOKING FOR THE LOW CLOUDS TO THIN OUT ACROSS THE
AREA BY LATE MORNING OR EARLY AFTERNOON. OTHERWISE...IT WILL BE
BREEZY DURING THE EARLY PART OF THE DAY...ESPECIALLY IN THE
EAST...WITH COLD AIR ADVECTION AND A DECENT GRADIENT ACROSS THE
AREA...THEN TAPERING DOWN IN THE AFTERNOON AS HIGH PRESSURE BUILDS
IN AND THE GRADIENT RELAXES AND ML WINDS DECREASE. THERMAL PROFILES
DO COOL A BIT TODAY...THOUGH NOTHING TOO EXTREME WITH HIGHS STILL
MAKING IT INTO THE MID 20S TO LOWER 30S FROM NORTHEAST TO SOUTHWEST
RESPECTIVELY.
THE HIGH PRESSURE MOVES QUICKLY TO THE EAST TONIGHT...AND WITH THAT
WINDS WILL TRANSITION TO SOUTHEASTERLY AND PICK UP LATER AT NIGHT.
IT WILL STILL BE A COLD NIGHT WITH LOWS IN THE UPPER SINGLE DIGITS
TO TEENS...WITH TEMPS STEADYING OUT OR RISING SOME LATE AT NIGHT AS
THE WINDS INCREASE.
.LONG TERM...(FRIDAY THROUGH WEDNESDAY)
ISSUED AT 520 AM CST THU NOV 28 2013
POTENT PACIFIC LOW DIVES INTO THE PACIFIC NORTHWEST FRIDAY AND
SATURDAY...SHIFTING THE INTERMOUNTAIN WEST RIDGING ITO THE PLAINS
STATES. A STRONG PUSH OF WARM AIR ADVECTION AND BREEZY SOUTHERLY
WINDS WILL BRING MILDER TEMPERATURES ON FRIDAY DESPITE SOME PASSING
MID AND HIGH CLOUDS FILTERING THE SUNSHINE. HIGHS WILL WARM TO
SLIGHTLY ABOVE NORMAL READINGS IN THE LOW 30S EAST TO THE MID 40S
WEST. A WEAK FRONT SAGS ACROSS THE FORECAST AREA FRIDAY NIGHT
THROUGH SATURDAY MORNING...BUT WITHOUT MOISTURE OR A REAL COLD AIR
PUSH BEHIND IT...CONDITIONS WILL REMAIN DRY AND MILD WITH HIGHS
MIXING INTO THE UPPER 30S TO MID 40S.
MUCH GREATER UNCERTAINTY SHOWS UP EARLY NEXT WEEK AS THE PACIFIC
TROUGH STRENGTHENS AND MOVES INTO THE NORTHERN ROCKIES. MODELS STILL
SHOWING SIGNIFICANT DIFFERENCES IN THE STRENGTH...TIMING AND TRACK
OF THE UPPER LOW. THE GFS FOLLOWS A MORE NORTHERLY TRACK WHILE THE
ECMWF IS SLOWER AND FURTHER SOUTH. FINALLY...THE CANADIAN DEPICTS A
MUCH WEAKER SYSTEM OVERALL WHICH GIVEN THE ENERGETIC NATURE OF THIS
SYSTEM SEEMS THE LEAST LIKELY.
INITIAL SHORTWAVE AHEAD OF THE MAIN SYSTEM SLIDES SOUTHEAST ACROSS
THE REGION AROUND THE SUNDAY NIGHT/MONDAY TIME FRAME. WITH THE GFS
RAPIDLY AMPLIFYING THE PAC NW TROUGH AND UPPER RIDGE AHEAD OF
IT...THIS WAVE IS WEAKER AND FASTER MOVING THAN THE ECMWF WHICH
DEVELOPS AN INVERTED TROUGH FEATURE OVER THE NORTHERN AND CENTRAL
PLAINS AND KEEPS IT IN THE PICTURE WELL INTO TUESDAY. SIGNIFICANT
DIFFERENCES IN TEMPERATURE PROFILES ALSO MAKE PRECIPITATION TYPES
DIFFICULT TO PINPOINT. TEMPERATURES LOOK TO REMAIN SEASONALLY MILD
THROUGH WEDNESDAY WITH MUCH COOLER READINGS ARRIVING LATE IN THE
WEEK. FOR NOW WILL KEEP MENTION OF BOTH RAIN AND SNOW. NOT MUCH
CONFIDENCE IN THE TIMING OF THE PRECIPITATION BUT CHANCES DO APPEAR
TO IMPROVE AS WE MOVE TOWARDS MID WEEK AS THE MAIN PACIFIC TROUGH
ADVANCES TOWARDS THE REGION. FOR NOW DID NOT ALTER THE ALLBLEND POPS
OR TEMPS MUCH GIVEN SUCH UNCERTAINTY.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z FRIDAY MORNING)
ISSUED AT 520 AM CST THU NOV 28 2013
STRATUS CONTINUES TO EXPAND SOUTHWARD BEHIND EXITING COLD
FRONT...AND THE CHALLENGE BECOMES WHEN THIS AREA OF LOW CLOUDS
WILL BREAK UP. WITH HIGH PRESSURE BUILDING ACROSS THE REGION AND
ASSOCIATED SUBSIDENCE AND DRYING...WOULD EXPECT CLOUDS TO BEGIN TO
DISSIPATE BY MID AFTERNOON. THERE IS SOME DISAGREEMENT AMONG
MODELS...WITH THE RAP HOLDING IT IN THROUGH AT LEAST LATE
AFTERNOON. AT THIS POINT WILL LEAN A LITTLE EARLIER WITH CLOUDS
SCATTERING OUT MOST PLACES AFTER AROUND 19Z. OTHERWISE...NORTHWESTERLY
WINDS...GUSTY AT TIMES EARLY...WILL TAPER DOWN...BECOMING LIGHT BY
THIS EVENING.
&&
.FSD WATCHES/WARNINGS/ADVISORIES...
SD...NONE.
MN...NONE.
IA...NONE.
NE...NONE.
&&
$$
UPDATE...CHAPMAN
SHORT TERM...
LONG TERM...JM
AVIATION...JM
AREA FORECAST DISCUSSION
NWS SIOUX FALLS SD
528 AM CST THU NOV 28 2013
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 520 AM CST THU NOV 28 2013
CURRENT SURFACE ANALYSIS SHOWS THE FRONTAL BOUNDARY HAVING PUSHED
THROUGH OUR CWA EARLY THIS MORNING...WITH AN AREA OF STRATUS
STREAMING INTO OUR WESTERN CWA BEHIND THE EXITING SYSTEM. THE
SURFACE RIDGE AXIS PRESENTLY LOCATED THROUGH THE WESTERN PORTIONS OF
THE DAKOTA WILL SLIDE TO THE SOUTH AND EAST TODAY...AND WITH DRYING
AND SUBSIDENCE LOOKING FOR THE LOW CLOUDS TO THIN OUT ACROSS THE
AREA BY LATE MORNING OR EARLY AFTERNOON. OTHERWISE...IT WILL BE
BREEZY DURING THE EARLY PART OF THE DAY...ESPECIALLY IN THE
EAST...WITH COLD AIR ADVECTION AND A DECENT GRADIENT ACROSS THE
AREA...THEN TAPERING DOWN IN THE AFTERNOON AS HIGH PRESSURE BUILDS
IN AND THE GRADIENT RELAXES AND ML WINDS DECREASE. THERMAL PROFILES
DO COOL A BIT TODAY...THOUGH NOTHING TOO EXTREME WITH HIGHS STILL
MAKING IT INTO THE MID 20S TO LOWER 30S FROM NORTHEAST TO SOUTHWEST
RESPECTIVELY.
THE HIGH PRESSURE MOVES QUICKLY TO THE EAST TONIGHT...AND WITH THAT
WINDS WILL TRANSITION TO SOUTHEASTERLY AND PICK UP LATER AT NIGHT.
IT WILL STILL BE A COLD NIGHT WITH LOWS IN THE UPPER SINGLE DIGITS
TO TEENS...WITH TEMPS STEADYING OUT OR RISING SOME LATE AT NIGHT AS
THE WINDS INCREASE.
.LONG TERM...(FRIDAY THROUGH WEDNESDAY)
ISSUED AT 520 AM CST THU NOV 28 2013
POTENT PACIFIC LOW DIVES INTO THE PACIFIC NORTHWEST FRIDAY AND
SATURDAY...SHIFTING THE INTERMOUNTAIN WEST RIDGING ITO THE PLAINS
STATES. A STRONG PUSH OF WARM AIR ADVECTION AND BREEZY SOUTHERLY
WINDS WILL BRING MILDER TEMPERATURES ON FRIDAY DESPITE SOME PASSING
MID AND HIGH CLOUDS FILTERING THE SUNSHINE. HIGHS WILL WARM TO
SLIGHTLY ABOVE NORMAL READINGS IN THE LOW 30S EAST TO THE MID 40S
WEST. A WEAK FRONT SAGS ACROSS THE FORECAST AREA FRIDAY NIGHT
THROUGH SATURDAY MORNING...BUT WITHOUT MOISTURE OR A REAL COLD AIR
PUSH BEHIND IT...CONDITIONS WILL REMAIN DRY AND MILD WITH HIGHS
MIXING INTO THE UPPER 30S TO MID 40S.
MUCH GREATER UNCERTAINTY SHOWS UP EARLY NEXT WEEK AS THE PACIFIC
TROUGH STRENGTHENS AND MOVES INTO THE NORTHERN ROCKIES. MODELS STILL
SHOWING SIGNIFICANT DIFFERENCES IN THE STRENGTH...TIMING AND TRACK
OF THE UPPER LOW. THE GFS FOLLOWS A MORE NORTHERLY TRACK WHILE THE
ECMWF IS SLOWER AND FURTHER SOUTH. FINALLY...THE CANADIAN DEPICTS A
MUCH WEAKER SYSTEM OVERALL WHICH GIVEN THE ENERGETIC NATURE OF THIS
SYSTEM SEEMS THE LEAST LIKELY.
INITIAL SHORTWAVE AHEAD OF THE MAIN SYSTEM SLIDES SOUTHEAST ACROSS
THE REGION AROUND THE SUNDAY NIGHT/MONDAY TIME FRAME. WITH THE GFS
RAPIDLY AMPLIFYING THE PAC NW TROUGH AND UPPER RIDGE AHEAD OF
IT...THIS WAVE IS WEAKER AND FASTER MOVING THAN THE ECMWF WHICH
DEVELOPS AN INVERTED TROUGH FEATURE OVER THE NORTHERN AND CENTRAL
PLAINS AND KEEPS IT IN THE PICTURE WELL INTO TUESDAY. SIGNIFICANT
DIFFERENCES IN TEMPERATURE PROFILES ALSO MAKE PRECIPITATION TYPES
DIFFICULT TO PINPOINT. TEMPERATURES LOOK TO REMAIN SEASONALLY MILD
THROUGH WEDNESDAY WITH MUCH COOLER READINGS ARRIVING LATE IN THE
WEEK. FOR NOW WILL KEEP MENTION OF BOTH RAIN AND SNOW. NOT MUCH
CONFIDENCE IN THE TIMING OF THE PRECIPITATION BUT CHANCES DO APPEAR
TO IMPROVE AS WE MOVE TOWARDS MID WEEK AS THE MAIN PACIFIC TROUGH
ADVANCES TOWARDS THE REGION. FOR NOW DID NOT ALTER THE ALLBLEND POPS
OR TEMPS MUCH GIVEN SUCH UNCERTAINTY.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z FRIDAY MORNING)
ISSUED AT 520 AM CST THU NOV 28 2013
STRATUS CONTINUES TO EXPAND SOUTHWARD BEHIND EXITING COLD
FRONT...AND THE CHALLENGE BECOMES WHEN THIS AREA OF LOW CLOUDS
WILL BREAK UP. WITH HIGH PRESSURE BUILDING ACROSS THE REGION AND
ASSOCIATED SUBSIDENCE AND DRYING...WOULD EXPECT CLOUDS TO BEGIN TO
DISSIPATE BY MID AFTERNOON. THERE IS SOME DISAGREEMENT AMONG
MODELS...WITH THE RAP HOLDING IT IN THROUGH AT LEAST LATE
AFTERNOON. AT THIS POINT WILL LEAN A LITTLE EARLIER WITH CLOUDS
SCATTERING OUT MOST PLACES AFTER AROUND 19Z. OTHERWISE...NORTHWESTERLY
WINDS...GUSTY AT TIMES EARLY...WILL TAPER DOWN...BECOMING LIGHT BY
THIS EVENING.
&&
.FSD WATCHES/WARNINGS/ADVISORIES...
SD...NONE.
MN...NONE.
IA...NONE.
NE...NONE.
&&
$$
SHORT TERM...
LONG TERM...JM
AVIATION...JM
SEE BELOW FOR AN UPDATED AVIATION FORECAST DISCUSSION.
&&
.PREVIOUS DISCUSSION...
.SHORT TERM...TODAY THROUGH SATURDAY
AN EXTENSIVE STRATUS DECK OVER THE REGION IS KEEPING TEMPERATURES
RELATIVELY MILD WITH CURRENT READINGS IN THE MID 20S. BASED ON THE
PAST FEW RUNS OF THE RUC...IT SEEMS UNLIKELY THIS STRATUS DECK
WILL DISSIPATE ANYTIME SOON. WOULD NOT BE TOO SURPRISED IF THESE
CLOUDS HANG AROUND THROUGH THIS AFTERNOON BEFORE DRIER AIR AT 925
MB MOVES IN FROM THE SOUTHWEST. OF COURSE THESE CLOUDS WILL MAKE
FORECASTING HIGH TEMPERATURES RATHER DIFFICULT. HAVE RELIED UPON
THE RUC MODEL WHICH SHOWS A SLIGHT COOL DOWN AROUND SUNRISE...THEN
A SLIGHT INCREASE BY 21Z.
HIGH PRESSURE SHIFTS EAST OF THE REGION TONIGHT...ALLOWING WAA TO
SPREAD ACROSS THE WESTERN CWA WHERE TEMPERATURES SHOULD BECOME
STEADY OR SLOWLY RISE AFTER MIDNIGHT. ANOTHER WEAK LOW PRESSURE
SYSTEM PASSING ACROSS THE REGION ON FRIDAY WILL BRING WARM
TEMPERATURES BACK INTO THE AREA. TEMPS AT 925/850 MB ARE PROJECTED
TO RANGE AROUND NORMAL...WHICH WHEN COMBINED WITH DECENT MIXING
WINDS SHOULD EQUAL HIGHS IN THE MID 30S...TO THE MID 40S. WOULD
NOT BE TOO SURPRISED IF HIGH TEMPERATURES END UP BEING WARMER.
SLIGHTLY COOLER LOW LEVEL TEMPERATURES ALONG WITH WEAK CAA ON
SATURDAY WILL RESULT IN HIGHS IN THE LOW TO MID 30S.
.LONG TERM...SATURDAY NIGHT THROUGH WEDNESDAY
LATEST MODEL RUNS CONTINUE TO FORECAST A MAJOR PATTERN SHIFT
DURING THE LONG TERM. HOWEVER THE DETAILS REMAIN SKETCHY AS EACH
MODEL HAS ITS OWN IDEA ON HOW TO HANDLE ENERGY WITHIN THE
DEVELOPING MID LEVEL TROF AND THAT TROFS EVOLUTION THROUGH THE
MIDDLE OF NEXT WEEK. THE ECMWF IS BY FAR THE MOST AGGRESSIVE IN
SETTING UP A BAROCLINIC ZONE ACROSS THE REGION AND CRANKS OUT
COPIOUS AMOUNTS OF PCPN FROM TUESDAY THROUGH THURSDAY. THE GFS IS
MORE PROGRESSIVE AND FEATURES A MORE POSITIVE TILT MID LEVEL TROF
OVER THE WESTERN/CENTRAL CONUS LEADING TO A LESS INTENSE
BAROCLINIC ZONE OVER THE NORTHERN PLAINS. THE LAST COUPLE RUNS OF
THE ECMWF HAVE BEEN CONSISTENTLY SLOWER AND WETTER VS THE GFS.
BUT IT SEEMS OVERLY WET. NONETHELESS WILL BE AN INTERESTING MIDDLE
OF NEXT WEEK WEATHER-WISE WITH A MIXED BAG OF PCPN EXPECTED NO
MATTER WHICH MODEL YOU LIKE. TEMPERATURES ARE EXPECTED TO BE ABOVE
NORMAL FOR THE FIRST PART OF THE PERIOD...BUT THEN TRANSITION
TOWARD NORMAL AS COLDER AIR INVADES FROM CANADA TOWARD MID TO LATE
WEEK.
&&
.AVIATION...
12Z TAFS FOR THE KABR...KATY...KPIR AND KMBG TERMINALS
MVFR CIGS ARE EXPECTED TO PERSIST AT LEAST INTO THE AFTERNOON FOR MOST
TERMINALS. MOST AREAS SHOULD BECOME VFR BY EVENING.
&&
.ABR WATCHES/WARNINGS/ADVISORIES...
SD...NONE.
MN...NONE.
&&
$$
UPDATE...TDK
SHORT TERM...SD
LONG TERM...TDK
AVIATION...TDK
WEATHER.GOV/ABERDEEN
AREA FORECAST DISCUSSION
NWS ABERDEEN SD
331 AM CST THU NOV 28 2013
.SHORT TERM...TODAY THROUGH SATURDAY
AN EXTENSIVE STRATUS DECK OVER THE REGION IS KEEPING TEMPERATURES
RELATIVELY MILD WITH CURRENT READINGS IN THE MID 20S. BASED ON THE
PAST FEW RUNS OF THE RUC...IT SEEMS UNLIKELY THIS STRATUS DECK
WILL DISSIPATE ANYTIME SOON. WOULD NOT BE TOO SURPRISED IF THESE
CLOUDS HANG AROUND THROUGH THIS AFTERNOON BEFORE DRIER AIR AT 925
MB MOVES IN FROM THE SOUTHWEST. OF COURSE THESE CLOUDS WILL MAKE
FORECASTING HIGH TEMPERATURES RATHER DIFFICULT. HAVE RELIED UPON
THE RUC MODEL WHICH SHOWS A SLIGHT COOL DOWN AROUND SUNRISE...THEN
A SLIGHT INCREASE BY 21Z.
HIGH PRESSURE SHIFTS EAST OF THE REGION TONIGHT...ALLOWING WAA TO
SPREAD ACROSS THE WESTERN CWA WHERE TEMPERATURES SHOULD BECOME
STEADY OR SLOWLY RISE AFTER MIDNIGHT. ANOTHER WEAK LOW PRESSURE
SYSTEM PASSING ACROSS THE REGION ON FRIDAY WILL BRING WARM
TEMPERATURES BACK INTO THE AREA. TEMPS AT 925/850 MB ARE PROJECTED
TO RANGE AROUND NORMAL...WHICH WHEN COMBINED WITH DECENT MIXING
WINDS SHOULD EQUAL HIGHS IN THE MID 30S...TO THE MID 40S. WOULD
NOT BE TOO SURPRISED IF HIGH TEMPERATURES END UP BEING WARMER.
SLIGHTLY COOLER LOW LEVEL TEMPERATURES ALONG WITH WEAK CAA ON
SATURDAY WILL RESULT IN HIGHS IN THE LOW TO MID 30S.
.LONG TERM...SATURDAY NIGHT THROUGH WEDNESDAY
LATEST MODEL RUNS CONTINUE TO FORECAST A MAJOR PATTERN SHIFT
DURING THE LONG TERM. HOWEVER THE DETAILS REMAIN SKETCHY AS EACH
MODEL HAS ITS OWN IDEA ON HOW TO HANDLE ENERGY WITHIN THE
DEVELOPING MID LEVEL TROF AND THAT TROFS EVOLUTION THROUGH THE
MIDDLE OF NEXT WEEK. THE ECMWF IS BY FAR THE MOST AGGRESSIVE IN
SETTING UP A BAROCLINIC ZONE ACROSS THE REGION AND CRANKS OUT
COPIOUS AMOUNTS OF PCPN FROM TUESDAY THROUGH THURSDAY. THE GFS IS
MORE PROGRESSIVE AND FEATURES A MORE POSITIVE TILT MID LEVEL TROF
OVER THE WESTERN/CENTRAL CONUS LEADING TO A LESS INTENSE
BAROCLINIC ZONE OVER THE NORTHERN PLAINS. THE LAST COUPLE RUNS OF
THE ECMWF HAVE BEEN CONSISTENTLY SLOWER AND WETTER VS THE GFS.
BUT IT SEEMS OVERLY WET. NONETHELESS WILL BE AN INTERESTING MIDDLE
OF NEXT WEEK WEATHER-WISE WITH A MIXED BAG OF PCPN EXPECTED NO
MATTER WHICH MODEL YOU LIKE. TEMPERATURES ARE EXPECTED TO BE ABOVE
NORMAL FOR THE FIRST PART OF THE PERIOD...BUT THEN TRANSITION
TOWARD NORMAL AS COLDER AIR INVADES FROM CANADA TOWARD MID TO LATE
WEEK.
&&
.AVIATION...
06Z TAFS FOR THE KABR...KATY...KPIR AND KMBG TERMINALS
MVFR STRATUS /1500FT TO 2500FT AGL CIGS/ IS SPREADING OVER ALL
FOUR TERMINALS. KATY SHOULD SEE THE STRATUS WORKING IN BY 08Z.
CURRENT MODEL DEPICTIONS SUGGEST THE CLOUDS ARE BREAKING UP OR
LIFTING BY AROUND 18Z THURSDAY. THERE COULD ALSO END UP BEING A
FEW SNOW FLURRIES OBSERVED FALLING OUT OF THIS STRATUS FIELD
BEFORE IT`S ALL SAID AND DONE. WINDS WILL BE FROM THE NORTHWEST AT
ALL FOUR TERMINALS THROUGH THURSDAY MORNING BEFORE SURFACE HIGH
PRESSURE BUILDING INTO THE REGION TURNS THEM LIGHT AND VARIABLE
AND THEN EVENTUALLY SOUTHEASTERLY AROUND 5 TO 10 KNOTS.
&&
.ABR WATCHES/WARNINGS/ADVISORIES...
SD...NONE.
MN...NONE.
&&
$$
SHORT TERM...SD
LONG TERM...TDK
AVIATION...DORN
WEATHER.GOV/ABERDEEN
AREA FORECAST DISCUSSION
NWS BLACKSBURG VA
925 PM EST FRI NOV 29 2013
.SYNOPSIS...
HIGH PRESSURE WILL BE ACROSS THE REGION THROUGH THE WEEKEND WHILE
A SERIES OF UPPER LEVEL DISTURBANCES PASS NORTH OF THE REGION. A
WEAK DISTURBANCE WILL PASS THROUGH THE AREA ON MONDAY WHILE AN
AREA OF LOW PRESSURE MOVES NORTH ALONG THE COAST. THE NEXT SYSTEM
TO BRING PRECIPITATION TO MOST OF OUR REGION WILL ARRIVE THURSDAY
INTO FRIDAY.
&&
.NEAR TERM /THROUGH SATURDAY/...
AS OF 920 PM EST FRIDAY
ADJUSTED OVERNIGHT MIN TEMPS DOWN A FEW DEGREES AS SKIES REMAIN
CLEAR SO FAR WITH CALMS WINDS NEARLY EVERYWHERE. STILL HOLDING TO
IDEA OF LOW CLOUDS DRIFTING SW ACROSS THE MOUNTAINS BY THE EARLY
MORNING HOURS AS SHOWN BY LATEST RAP AND NAM MODELS WHICH WOULD
ARREST THE DOWNWARD TRAJECTORY IN TEMPS SOMEWHAT. LOWERED WINDS
SLIGHTLY AS WELL BUT OTHERWISE NO SUBSTANTIVE CHANGES.
PREVIOUS VALID DISCUSSION
AS OF 300 PM EST FRIDAY...
A WEAK UPPER LEVEL DISTURBANCE WILL PROGRESS THROUGH THE GREAT LAKES
REGION TONIGHT INTO SATURDAY. SURFACE HIGH PRESSURE WILL BECOME
CENTERED OVER NEW ENGLAND BY SATURDAY MORNING...AND ITS ASSOCIATED
RIDGE AXIS WILL TRAIL SOUTHWEST ALONG THE LEE OFF THE APPALACHIANS.
LOW LEVEL MOISTURE HAS BEEN ABUNDANT TODAY FROM NORTHERN WEST
VIRGINIA...NORTH INTO PENNSYLVANIA.
TWO WEATHER PATTERNS WILL CONTRIBUTE TO INCREASING CLOUD COVER
TONIGHT INTO SATURDAY. FIRST...THE ADVANCING SYSTEM THROUGH THE
GREAT LAKES REGION HAS ALREADY ALLOWED FOR SOME DOWNSTREAM
ADVANCEMENT OF MID TO HIGH LEVEL CLOUD COVER OVER PARTS OF INDIANA
AND KENTUCKY. THIS CLOUD COVER WILL PROGRESS INTO OUR REGION
OVERNIGHT WITH INCREASING COVERAGE THROUGH SATURDAY. THE GREATEST
CONCENTRATION WILL OVER THE NORTHERN PARTS OF THE FORECAST AREA.
SECOND...BOTH 12Z/7AM GFS AND TO A GREATER DEGREE THE 12Z/7AM NAM
ARE DEPICTING A SOUTHERN ADVANCEMENT OF THE WV/MD/PA MOISTURE ALONG
THE LEE OF THE APPALACHIANS OVERNIGHT. THIS MOISTURE IS DEPICTED AS
BEING SHALLOW WITHIN ROUGHLY THE 925-900 MB LAYER. 925 MB WINDS WILL
BE COMPARABLE TO THE ORIENTATION TYPICALLY ASSOCIATED WITH ONSET OF
A HIGH PRESSURE RIDGE ALONG COMMON DAMMING AREA. 925 MB WINDS WILL
GRADUALLY VEER OVERNIGHT TO NORTHEAST AND THEN TO THE EAST. THE
WV/MD/PA MOISTURE IS PROGGED TO GET CAUGHT UP IN THIS FLOW AND
EVENTUALLY TAKE AN UPSLOPE ORIENTATION TO THE BLUE RIDGE. THIS WILL
HELP IN THE FORMATION OF LOW LEVEL CLOUD COVER ACROSS THOSE REGIONS
OF THE FORECAST AREA GENERALLY ALONG AND WEST OF THE CREST OF THE
BLUE RIDGE. THE WINDOW OF BEST COVERAGE WILL BE FROM ROUGHLY 300 AM
SATURDAY THROUGH 10AM SATURDAY. PAST THIS POINT THE NOCTURNAL
INVERSION WILL HAVE ERODED AND THE CLOUDS BEGIN TO DISSIPATE. FOR
LOWS TONIGHT...I HAVE FAVORED NUMBERS AT OR SLIGHTLY ABOVE GUIDANCE
IN THOSE AREAS THAT WILL EXPERIENCE THE BULK OF THE AFOREMENTIONED
CLOUD COVER.
FOR SATURDAY...THE REGION WILL STILL BE CONTENDING WITH THE MID TO
HIGH LEVEL CLOUD COVER...AGAIN PRIMARILY IN THE NORTH...IN
ASSOCIATION WITH PASSING SHORTWAVE TROUGH TO OUR NORTH. CLOSER TO THE
SURFACE...THE 925 MB FLOW BECOMES EASTERLY THE WHOLE WAY TO THE
COAST. THIS WILL ALLOW ATLANTIC MOISTURE TO PROGRESS INTO AT LEAST
THE PIEDMONT REGION OF THE FORECAST AREA BY THE LATE AFTERNOON. WILL
BE SHOWING INCREASING CLOUD COVER IN THIS REGION TO ACCOUNT FOR
THIS. HAVE NOT DEVIATED TOO FAR FROM A BLEND OF THE GFS AND NAM MOS
FOR HIGH TEMPERATURES.
&&
.SHORT TERM /SATURDAY NIGHT THROUGH MONDAY NIGHT/...
AS OF 240 PM EST FRIDAY...
ZONAL FLOW ALOFT OVER THE MID APPALACHIAN AND MID ATLANTIC REGION
WILL GRADUALLY BE REPLACED BY MEAN TROFING OVER THE EASTERN PORTION
OF THE NATION BY THE END OF THE SHORT TERM PERIOD AS A SERIES OF
WEAK SHORT WAVE TROFS EMBEDDED IN NORTHERN STREAM HELPS TO SLOWLY
BUCKLE UPPER FLOW.
PRESENCE OF WEAK SURFACE HIGH PRESSURE...NEGLIGIBLE THERMAL
ADVECTION...AND PRESENCE OF HIGH AND OCCASIONALLY MID LEVEL CLOUDS
UNDER REGION OF CHANNELIZED VORTICITY SHOULD MAINTAIN RATHER
UNEVENTFUL WEATHER OVER THE BLACKSBURG FORECAST AREA SATURDAY NIGHT
THROUGH SUNDAY NIGHT WITH SOMEWHAT MODERATED DIURNAL TEMPERATURE
PROFILE. NIGHTTIME LOWS EXPECTED TO RANGE FROM THE MID 20S TO LOWER
30S IN MOST AREAS...WITH COOLEST READINGS IN THE DEEPER VALLEYS...
AND MILDER READINGS ACROSS THE RIDGELINES AND NC FOOTHILLS. DAYTIME
HIGHS ON SATURDAY EXPECTED TO RANGE FROM THE LOWER TO MID 40S IN THE
MOUNTAINS TO LOWER 50S ACROSS THE PIEDMONT.
A MORE SIGNIFICANT SHORT WAVE IS EXPECTED TO AMPLIFY UPPER FLOW AS
IT DIVES EAST-SOUTHEAST OUT OF THE MISSISSIPPI VALLEY ON
MONDAY...REACHING THE EAST COAST BY LATE MONDAY NIGHT. BACKING FLOW
ALOFT WILL HELP STRENGTHEN BAROCLINIC ZONE ALONG THE SOUTHEAST
COAST...RESULTING IN CYCLOGENESIS WITH SURFACE LOW EXPECTED TO
DEVELOP AND STRENGTHEN ALONG THE COAST BY LATE IN SHORT TERM PERIOD.
MID-RANGE MODELS NOT YET CONSISTENTLY RESOLVING DEVELOPMENT...
PLACEMENT...AND TIMING OF THIS FEATURE...YET MOST IMPLY THAT FLOW
WILL NOT AMPLIFY SUFFICIENTLY OR SOON ENOUGH TO ALLOW DEVELOPING
AREA OF PRECIPITATION IN ISENTROPIC ZONE TO SIGNIFICANTLY THREATEN
BLACKSBURG AREA OF CONCERN BEFORE MOVING OFF THE EAST.
CONSIDERING THAT PAST COUPLE OF MODEL TRENDS HAVE BECOME A BIT MORE
BULLISH IN AMPLIFICATION OF THIS SYSTEM...WILL CONTINUE TO MAINTAIN A
LOW THREAT FOR PRECIPITATION IN MOST AREAS MONDAY AFTERNOON INTO
MONDAY NIGHT...WITH HIGHEST THREAT FOR PRECIPITATION EXPECTED TO BE
RESTRICTED TO MAINLY NORTHWESTERN MOUNTAINS WHERE LOCAL UPSLOPING
WILL BE MAXIMIZED.
CONSIDERING THERMAL PROFILE...ANY PRECIPITATION ON MONDAY WILL
LIKELY COME IN THE FORM OF SPOTTY LIGHT SHOWERS...HOWEVER INCREASING
COLD ADVECTION ON BACKSIDE OF COASTAL LOW WILL LIKELY BE/BECOME
SUFFICIENT ENOUGH TO ALLOW CHANGEOVER TO SNOW OR RAIN/SNOW MIX IN
MOUNTAINS ON MONDAY NIGHT. FURTHER EAST...EVEN IF COASTAL LOW IS
ABLE TO CRANK UP FAST ENOUGH TO PUSH PRECIPITATION UNDER DEVELOPING
DEFORMATION ZONE WESTWARD INTO EASTERN PIEDMONT COUNTIES...THERMAL
PROFILE IN THAT AREA LIKELY TO REMAIN ABOVE FREEZING (HENCE ONLY A
COLD RAIN) UNTIL SYSTEM LIFTS AWAY FROM THE AREA BY/BEFORE DAYBREAK
TUESDAY.
&&
.LONG TERM /TUESDAY THROUGH FRIDAY/...
AS OF 300 PM EST FRIDAY...
THE BEGINNING OF THE LONG TERM PERIOD WILL BEGIN WITH SOME UPSLOPE
PRECIPITATION ACROSS THE MOUNTAINS. BOTH THE GFS AND THE ECMWF SHOW
PRECIPITATION THROUGH ABOUT 6Z WEDNESDAY. LIKELY WILL BE SNOW
SHOWERS ACROSS WESTERN GREENBRIER WITH A MIX OF RAIN AND SNOW ACROSS
LOWER ELEVATION MOUNTAIN AREAS. MODELS ALSO AGREE THAT THERE WILL
CONTINUE TO BE A GENERAL WARMING TREND AS 500 MB HEIGHT LEVELS
CONTINUE TO RISE THROUGH THE WEEK. FROM THURSDAY ON THROUGH SATURDAY
850MB TEMPS WILL BE +5-10C. THIS SHOULD ALLOW DAYTIME MAX TEMPS TO
EASILY REACH THE 50S AND EVEN LOWER 60S EAST OF THE BLUE RIDGE BY
THE END OF THE WEEK.
WHILE WE WILL BE WARMER...A STRONG COLD FRONT WILL BEGIN TO APPROACH
THE REGION ON THURSDAY AND FRIDAY. BOTH THE GFS AND ECMWF BRING
MOISTURE IN AHEAD OF THE FRONT. CHANCE SHOWERS ARE MENTIONED FROM
THURSDAY THROUGH THE REST OF THE LONG TERM PERIOD ON 12Z SATURDAY.
LOOKING BEYOND SATURDAY...A DEEP TROUGH ACROSS THE WESTERN UNITED
STATES WILL BRING PLENTY OF COLD AIR FROM CANADA ALL THE WAY INTO
THE CENTRAL PLAINS. BY THE END OF THE 240HR MODEL RUN OUR REGION
CONTINUES TO BE UNDER THE INFLUENCE OF THE RIDGE AND THUS WILL STAY
ON THE WARMER SIDE. A CLOSER EYE WILL BE PAID TO FUTURE MODEL RUNS
TO SEE HOW THE PATTERN PROGRESSES.
&&
.AVIATION /03Z SATURDAY THROUGH WEDNESDAY/...
AS OF 630 PM EST FRIDAY...
VFR CONDITIONS PREVAIL ACROSS THE REGION THIS EVENING AS HIGH
PRESSURE BUILDS INTO THE REGION BUT SHORT-WAVR PASSING TO OUR
NORTH HAS BROUGHT SOME LOW LEVEL MOISTURE AS CLOSE TO THE REGION
AS NORTHERN WV AND SOUTHERN PA. OVERNIGHT...MODELS CONTINUE TO
SHOW SOME OF THIS LOW LEVEL MOISTURE OVER WV/MD/PA WORKING SOUTH
AND THEN WEST AS LOW LEVEL WINDS VEER MORE TO THE NORTHEAST OVER
THE PIEDMONT AND EAST OVER THE MOUNTAINS. RAP/NAM/GFS MODELS ALL
CONTINUE TO SHOW THIS SHALLOW RIBBON OF MOISTURE AROUND THE
925-900 MB LEVEL ADVECTING INTO THE REGION BETWEEN ROUGHLY 03Z-06Z
/10PM- 1AM TONIGHT AND PROVIDE FOR SCT-BKN MVFR LEVEL CLOUDS. THE
CONCENTRATION IS EXPECTED TO BE GREATEST ALONG AND WEST OF A KTNB-
KBCB-KLWB LINE. THIS MOISTURE WILL REMAIN TRAPPED UNDER THE
NOCTURNAL INVERSION UNTIL IT HAS A CHANCE TO ERODE AROUND 14Z-15Z
/9AM-10AM SATURDAY.
ADDITIONAL MVFR CLOUDS ARE POSSIBLE SATURDAY AFTERNOON AND EVENING AS
LOW LEVEL WINDS ACROSS THE PIEDMONT VEER MORE EASTERLY AND WE
START TO TAP ATLANTIC MOISTURE INTO THE REGION. BY LATE SATURDAY
NIGHT LOW LEVEL WINDS ARE EXPECTED TO HAVE VEERED SOUTHWEST...AND
WE LOSE THE UPLSOPE COMPONENT RESPONSIBLE FOR THE MVFR CLOUDS.
SUNDAY INTO MONDAY MAINLY VFR CONDITIONS ARE EXPECTED AS WE BECOME
POSITIONED BETWEEN A LOW MOVING NORTH ALONG THE COAST AND A TROUGH
AXIS OVER THE OH/TN VALLEY. ISOLATED TO SCATTERED RAIN/SNOW
SHOWERS WILL BE POSSIBLE BY MONDAY NIGHT AS THE TROUGH APPROACHES
FROM THE WEST.
TUESDAY INTO WEDNESDAY MAINLY VFR CONDITIONS ARE EXPECTED AS THE
TROUGH PASSES TO OUR EAST AND AN AREA OF LOW PRESSURE DEVELOPS OFF
THE COAST. OUR REGION WILL BE LEFT IN A NORTHWEST FLOW PATTERN
WITH THE POTENTIAL FOR UPSLOPE CLOUDS OVER THE MOUNTAINS. THERE
MAY BE PATCHY MVFR CIGS WITHIN THESE.
&&
.RNK WATCHES/WARNINGS/ADVISORIES...
VA...NONE.
NC...NONE.
WV...NONE.
&&
$$
SYNOPSIS...DS
NEAR TERM...DS/PC
SHORT TERM...WERT
LONG TERM...CF
AVIATION...DS/PC
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
325 PM CST THU NOV 28 2013
.SHORT TERM...(THIS EVENING THROUGH FRIDAY)
ISSUED AT 325 PM CST THU NOV 28 2013
AT 3 PM...A LAKE INDUCED VORTICITY WAS LOCATED OVER THE APOSTLE
ISLANDS IN WESTERN LAKE SUPERIOR. MEANWHILE A SURFACE LOW WAS
LOCATED OVER EASTERN UPPER MICHIGAN. THIS LOW WAS PRODUCING WEAK
CYCLONIC FLOW ACROSS ACROSS WISCONSIN AND EAST CENTRAL MINNESOTA.
THIS CYCLONIC FLOW ALONG WITH STEEP 950-900 MB LAPSE RATES
/ASSOCIATED WITH A THERMAL TROUGH LOCATED FROM NORTHERN MINNESOTA
SOUTHEAST INTO EASTERN WISCONSIN/ IS HELPING MAINTAIN THESE
CLOUDS. THE 28.19Z RAP HAS A VERY GOOD HANDLE ON THESE CLOUDS AND
THEY SHOW THAT THEY WILL CONTINUE TO MOVE SOUTHEAST ACROSS MAINLY
OUR WISCONSIN COUNTIES AND THEN QUICKLY DISSIPATES THEM BETWEEN
28.01Z AND 28.03Z AS THE FLOW STARTS TO BECOME ANTICYCLONIC AND
THE 950-900 MB LAPSE RATES DECREASE.
FROM LATE TONIGHT INTO FRIDAY...THE 28.12Z MODELS CONTINUE TO
SHOW THAT WEAK WARM AIR ADVECTION WILL DEVELOP ABOVE 600 MB AS A
WEAK SHORT WAVE TROUGH APPROACHES THE REGION FROM THE CENTRAL
PLAINS. THIS WILL RESULT IN SOME MID TO HIGH CLOUDS ACROSS THE
AREA.
.LONG TERM...(FRIDAY NIGHT THROUGH THURSDAY)
ISSUED AT 325 PM CST THU NOV 28 2013
ON FRIDAY NIGHT...THE 28.12Z MODELS CONTINUE TO SHOW THAT A STRONG
SHORT WAVE TROUGH WILL MOVE SOUTHEAST ACROSS SOUTHWEST ONTARIO.
MUCH OF THE PV ADVECTION ASSOCIATED WITH THIS SYSTEM STAYS WILL
NORTH OF THE FORECAST AREA. THERE IS WEAK TO MODERATE 285 TO 300K
ISENTROPIC LIFT ACROSS NORTHERN AND EASTERN WISCONSIN. THIS LOWERS
THE CONDENSATION PRESSURE DEFICITS TO LESS 40 MB. MEANWHILE AT THE
285 AND 290K ISENTROPIC SURFACES YOU STILL NEED 100 TO 200 MB
OF LIFT FOR SATURATION. AS A RESULT...IT IS NOT LOOKING PROMISING
FOR ANY PRECIPITATION ACROSS TAYLOR AND NORTHERN CLARK COUNTY IN
NORTH CENTRAL WISCONSIN. HOWEVER WITH THE ECMWF...GEM...AND NAM
STILL INDICATING A POSSIBILITY. JUST KEPT A SLIGHT CHANCE /LESS
THAN 20 PERCENT/ ACROSS THIS AREA. BUFKIT SOUNDINGS CONTINUE TO
SHOW NO ICE...SO IF PRECIPITATION DOES INDEED OCCURS IT WOULD BE
IN THE FORM OF FREEZING DRIZZLE.
ON SATURDAY NIGHT...WEAK TO MODERATE WARM AIR ADVECTION AND STRONG
290 TO 300K ISENTROPIC LIFT DEVELOP ACROSS THE AREA AS A STRONG
SHORT WAVE TROUGH MOVES ACROSS THE REGION. THE 290-300K ISENTROPIC
CONDENSATION PRESSURE DEFICITS DROP TO LESS THAN 30 MB...SO WE
WILL LIKELY SEE CLOUDS WITH THIS WAVE. HOWEVER...THE 285K
CONDENSATION DEFICITS REMAIN IN THE 100 TO 200 MB RANGE...SO NOT
EXPECTING ANY PRECIPITATION WITH THIS WAVE.
FROM SUNDAY NIGHT INTO MONDAY...THE MODELS CONTINUE TO STRUGGLE
WITH THE TIMING OF A SHORT WAVE TROUGH COMING OUT AHEAD OF THE
DEVELOPING LONG WAVE TROUGH IN THE WESTERN UNITED STATE. BOTH THE
GEM AND ECMWF BRING A WAVE AHEAD OF THIS SYSTEM. MEANWHILE THE GFS
DOES NOT. AS AS RESULT...THE GEM AND ECMWF PRODUCES SOME LIGHT
PRECIPITATION ACROSS THE AREA. MEANWHILE THE GFS KEEPS THE AREA
DRY. SINCE THE MODELS HAVE BEEN CONSISTENT...JUST STAYED WITH THE
SLIGHT CHANCES THAT THE ALL BLEND PROVIDED.
FROM MONDAY NIGHT THROUGH THURSDAY...THE MODELS CONTINUE TO
STRUGGLE WITH THE EVOLUTION OF A LONG WAVE TROUGH OVER THE WESTERN
UNITED STATES. DUE TO THIS...THERE HAS BEEN A VARIETY OF DIFFERENT
LOW PRESSURE TRACKS FROM THE NORTHERN PLAINS EAST INTO THE GREAT
LAKES. THIS SYSTEM HAS THE POTENTIAL OF PRODUCING A WINTER STORM
SOMEWHERE ACROSS THE REGION...BUT WHERE IS VERY UNCERTAIN...SO
JUST STAYED WITH THE ALL BLEND FOR THIS TIME PERIOD.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z FRIDAY AFTERNOON)
ISSUED AT 1130 AM CST THU NOV 28 2013
SKIES HAVE CLEARED OUT TO START THE TAF FORECAST. A LOW PRESSURE
TROUGH WAS SEEN UPSTREAM NEAR MSP...PRODUCING SOME MVFR TO VFR
STRATOCUMULUS AND EVEN A FEW FLURRIES. IF THIS TROUGH AND CLOUDS
HOLD TOGETHER...THEY WILL ARRIVE IN THE TAF SITES BETWEEN 20-22Z
AND HANG AROUND FOR A FEW HOURS. THINKING THE CEILINGS WILL RISE
AS THEY RUN INTO DRIER AIR AHEAD OF THEM...THUS HAVE MAINTAINED A
SCATTERED VFR CLOUD DECK THROUGH THE AFTERNOON. NEEDLESS TO SAY
SOMETHING TO WATCH DURING THE AFTERNOON HOURS. OTHERWISE...ANY OF
THIS STRATOCUMULUS SHOULD EITHER EXIT OR DISSIPATE AROUND THE TAF
SITES BY 01Z...WITH VFR CONDITIONS PERSISTING THROUGH FRIDAY
MORNING. NORTHWEST WINDS OF 10-15KT ARE EXPECTED TO DIMINISH THIS
EVENING WITH LOSS OF DAYTIME HEATING AND A RIDGE OF HIGH PRESSURE
MOVING IN.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
SHORT TERM...BOYNE
LONG TERM...BOYNE
AVIATION...AJ
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
1134 PM CST WED NOV 27 2013
.UPDATE...
ISSUED AT 712 PM CST WED NOV 27 2013
FRONTOGENETIC BAND FROM NORTHERN MINNESOTA INTO NORTH CENTRAL
WISCONSIN CONTINUES TO PRODUCE EFFICIENT SNOW AMOUNTS WITH DECENT
LIFT IN DENDRITIC SNOW GROWTH ZONE. REPORTS OF 2 TO 4 INCHES
UPSTREAM...AND EVEN THOUGH FORCING IS FORECAST TO WEAKEN AS SYSTEM
ADVECTS EAST...BUMPED UP SNOW ACCUMULATIONS SLIGHTLY MAINLY ALONG
AND NORTH OF HIGHWAY 29 IN PARTS OF NORTH CENTRAL WISCONSIN TONIGHT.
&&
.SHORT TERM...(THIS EVENING THROUGH THANKSGIVING)
ISSUED AT 310 PM CST WED NOV 27 2013
OVERALL A QUIET WEATHER PERIOD THROUGH THE WEEKEND...AFTER SOME
LIGHT SNOW ACROSS THE NORTH TONIGHT.
HAVE BEEN MONITORING SHORTWAVE TROUGH 1 MOVING INTO MINNESOTA
THIS AFTERNOON WITH LIGHT SNOW IN THE 1-2SM VISIBILITY
RANGE...WITH A BIT LOWER FURTHER NORTHWEST ALONG THE MN/CANADA
BORDER. ECHO IS INCREASING IN NW WI...BUT THE PRECIPITATION IS
WORKING ON SATURATION AND NOT MAKING IT TO THE SURFACE. THE UPPER
TROPOSPHERIC SHORTWAVE TROUGH IS LOCATED IN NWRN MN AT 20Z PER
GOES WATER VAPOR IMAGERY...WITH SHORTWAVE TROUGH 2 ON ITS HEALS
JUST NORTHWEST OF LAKE WINNIPEG. MORNING RAOB AT KMPX WAS DEEPLY
DRY BUT THE FORCING WITH THE SHORTWAVE TROUGH IS WORKING PRETTY
RAPIDLY TO SATURATE THE COLUMN AND PRODUCE SNOW....ON THE ORDER OF
A COUPLE HOURS. PER THE LATEST RAP...THIS FORCING IS A
CONTRIBUTION FROM WARM ADVECTION IN THE LOW LEVELS / AND 700MB
FRONTOGENESIS/ AND MID-UPPER LEVEL QG CONVERGENCE.
THE FIRST SHORTWAVE WILL TRACK TOWARD THE NORTHERN FORECAST AREA THIS
AFTERNOON AND ARRIVE AROUND 6-7 PM IN CLARK AND TAYLOR COUNTIES
PER RAP FORECASTS AND TRACKING. THIS FIRST SHORTWAVE TROUGH
WEAKENS AS IT MOVES IN PER THE CONSENSUS MODEL GUIDANCE AS THE
SECOND WAVE INTENSIFIES AND DEEPENS. HOWEVER...THERE IS GUIDANCE
/HRRR/ SOLUTIONS DIMINISHING THE WEATHER AS IT MOVES SOUTHEAST
AND DRY AIR IN PLACE WILL DOMINATE. WITH CONSENSUS FORCING SWIPING
A BAND OF SNOW IN THE EVENING AND CURRENT CONDITIONS...HAVE
FORECAST THE SNOW TO MOVE IN DURING THE EVENING AND ACCUMULATE...MAINLY
I-94 AND NORTH. THIS IS NOT A BIG CHANGE TO ONGOING FORECAST..BUT
HIGHER CONFIDENCE. WILL LIKELY HIT THIS A BIT IN THE SOCIAL MEDIA
AND SPECIAL WEATHER STATEMENTS WITH MORE TRAVEL THIS EVENING
HAPPENING.
SOME DIFFICULTY IN TRYING TO FIGURE OUT THE REMAINDER OF THE
NIGHT AFTER MIDNIGHT...AHEAD OF THE SECOND SHORT WAVE TROUGH. IT
APPEARS THE FRONTOGENESIS NEAR 700MB WILL BE STRONGER THAN THE
FIRST SHORTWAVE AND WITH THE UPPER QG FORCING MAINLY OVER NRN WI
/MODEL CONSENSUS/...SNOW SEEMS TO BE A GIVEN. BUT AS SHORTWAVE
TROUGH 2 DEEPENS...THE FORCING SHIFTS INTO NORTHERN WI AND MAY
SPREAD ITS SNOW NORTH OF TAYLOR COUNTY. FEEL FAIRLY CONFIDENT SNOW
WILL OCCUR OVERNIGHT...BUT HAVE DECIDED TO MOVE IT NORTH WITH TIME
AND LEAVE FLURRIES SOUTH TO I-94. THE SNOW RATIOS COULD BE QUITE
HIGH WITH THIS SNOW WITH MOST OF THE SATURATED COLUMN IN THE
DENDRITE GROWTH ZONE -12 TO -18C...THUS LOW QPF COULD PRODUCE AN
INCH PRETTY EASY.
MAINLY FLURRIES SHOULD REMAIN DURING THE EARLY MORNING THURSDAY WITH
ROADS CLEANING UP FOR TRAVEL. SUN IS EXPECTED BY AFTERNOON.
.LONG TERM...(THURSDAY NIGHT THROUGH WEDNESDAY)
ISSUED AT 310 PM CST WED NOV 27 2013
A PERIOD OF QUIET WEATHER WITH SOME MODERATION IN TEMPERATURES
BEGINNING FRIDAY...BUT A COLD START THAT MORNING UNDER HIGH
PRESSURE AND CLEAR SKIES. IF A BIT MORE SNOW FALLS IN TAYLOR
COUNTY TONIGHT ACROSS TAYLOR COUNTY...FRIDAY MORNING COULD BE NEAR
ZERO.
NEXT WEATHER SYSTEM SHIFTS ACROSS NORTHERN GREAT LAKES FRIDAY
NIGHT AND SATURDAY WITH THE MORE FAVORABLE FORCING NORTH OF THE
AREA. MAYBE SOME CLOUDS AND FLURRIES IN TAYLOR COUNTY BUT HAVE
KEPT DRY FORECAST INTACT.
SUNDAY THROUGH WEDNESDAY...LOW CONFIDENCE IN THIS PERIOD AS THE
MODEL GUIDANCE HAS DIFFERENT EVOLUTIONS AND TIMING TO THE MAJOR
READJUSTMENT OF THE LARGE SCALE PATTERN OVER NORTH AMERICA. MAJOR
TROUGH AND COLD POOL OF AIR INVADE THE WESTERN CONUS WITH AN
ASTOUNDING -3.5 TO -4 STANDARD DEVIATION BELOW NORMAL 850 MB TEMP
IN THE WESTERN CONUS. BECAUSE OF THE SPREAD IN THE MODELS AND HOW
ENERGY EJECTS OUT OF THE TROUGH...THE FORECAST HAS SMALL
PRECIPITATION CHANCES MONDAY TO WEDNESDAY. THIS COULD BE A DRY
PERIOD SHOULD THE 27.12Z ECMWF SOLUTION OCCUR...WHICH THE 27.12Z
GFS TRENDED TOWARD...WITH MORE WEATHER LATER IN THE WEEK.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z FRIDAY MORNING)
ISSUED AT 1134 PM CST WED NOV 27 2013
MID LEVEL FRONTOGENETIC BAND MOVING ACROSS CENTRAL WISCONSIN IS ONLY
AVIATION IMPACT TONIGHT BUT THAT FEATURE IS QUICKLY PUSHING OFF TO
THE EAST. MEANWHILE NEXT SHORT WAVE WILL BRING A COLD FRONT INTO THE
AREA EARLY THANKSGIVING MORNING AND SHALLOW COLD AIR ADVECTION
THROUGH MUCH OF THE DAY. EXTENSIVE STRATUS FIELD UPSTREAM SUGGESTS
IDEA OF MORE CLOUDS IS ON TRACK WITH INVERSION SETTING UP. DRY
AIRMASS ALOFT BUT IT WILL TAKE SOME TIME TO MIX OUT STRATUS FIELD
LOCKED BELOW.
GENERALLY CONDITIONS WILL REMAIN VFR BUT COULD SEE SOME MVFR
CEILINGS AT TIME...ESPECIALLY NORTH OF INTERSTATE 90 THURSDAY
MORNING. WILL BE OPTIMISTIC THAT CEILINGS WILL BREAK UP HEADING INTO
THURSDAY EVENING AS RIDGE BUILDS IN.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
UPDATE........SHEA
SHORT TERM...BAUMGARDT
LONG TERM...BAUMGARDT
AVIATION...SHEA
AREA FORECAST DISCUSSION
NWS CHEYENNE WY
1032 AM MST THU NOV 28 2013
.SHORT TERM...(TODAY THROUGH SATURDAY)
ISSUED AT 332 AM MST THU NOV 28 2013
10Z SURFACE ANALYSIS SHOWS THE COLD FRONT BISECTING THE CWA FROM
NORTHWEST TO SOUTHEAST WITH LIGHT WINDS THROUGHOUT THE AREA. HIGH
CLOUDS ARE STREAMING OVERHEAD IN NORTHWEST FLOW WITH A STRATUS DECK
CREEPING SOUTH-SOUTHWESTWARD ACROSS THE CENTRAL PLAINS AND TOWARD
THE NORTHERN NEBRASKA PANHANDLE. CURRENT TRENDS COMBINED WITH NAM
BUFKIT SOUNDINGS AND RECENT HRRR RUNS SUGGEST THAT THIS STRATUS DECK
WILL IMPACT CHADRON AROUND SUNRISE AND MAY SNEAK INTO ALLIANCE AS
WELL THROUGH THE MORNING. GUIDANCE ALSO SUGGESTS THE LOW CLOUDS WILL
PERSIST THROUGH THE MORNING...AND WILL SCATTER OUT SLOWLY WITH
INCREASED SOLAR INSOLATION. IN ADDITION...SOUTHEASTERLY WINDS WILL
BECOME BREEZY ACROSS THE EASTERN PLAINS AS THE SFC HIGH SLIDES
SOUTH-SOUTHEAST ACROSS THE CENTRAL PLAINS. THIS WILL ADVECT SOME
LLVL MOISTURE INTO THE EASTERN PLAINS AND LIKELY CONTRIBUTE TO THE
SLOWER MIXING OUT OF THE STRATUS. INCREASED CLOUD COVER FOR TODAY IN
THIS AREA AS A RESULT...AND LOWERED MAX TEMPS A FEW DEGREES DUE TO THE
MORE PERSISTENT CLOUD DECK. OTHERWISE...EXPECTING A DRY...CALM
THANKSGIVING DAY WITH LIGHT WINDS AND CONTINUAL HIGH CIRRUS MOVING
OVERHEAD FROM THE NORTHWEST.
TONIGHT...A SHORTWAVE WILL MOVE EASTWARD ACROSS CENTRAL CANADA WHILE
A SECOND WEAK WAVE WILL MOVE ACROSS COLORADO. THE COMBINATION OF
FEATURES WILL DEEPEN THE LEESIDE SFC PRESSURE TROUGH...ALTHOUGH THE
DEEPEST PRESSURE FALLS WILL REMAIN WELL REMOVED FROM THE REGION AND
THEREFORE THE SFC PRESSURE GRADIENT WILL NOT BECOME VERY STRONG.
STILL LOOKING AT 850/700 MB CAG-CPR GRADIENTS OF 30 DAM OR LESS BY
EARLY FRIDAY MORNING. A LOOK AT A CROSS SECTION OF LAPSE RATES AND
WINDS THROUGH THE WIND PRONE REGIONS ALONG AND WEST OF THE LARAMIE
RANGE SHOWS THE INCREASE IN WINDS WITH THE STRENGTHENING
GRADIENT...BUT THE INVERSION REMAINS NEAR THE GROUND EARLY FRIDAY
MORNING WHICH SHOULD MINIMIZE GAP EFFECTS. THE INVERSION WILL LIFT
JUST OFF THE SURFACE AND WILL REMAIN RELATIVELY WEAK THROUGH
FRIDAY...BUT SHOULD BE STRONG ENOUGH TO PRODUCE MODERATE
GRADIENT/GAP WINDS THROUGH FRIDAY NIGHT. LOOKING AT SUSTAINED
WEST-SOUTHWEST WINDS IN THIS AREA ON AVERAGE OF 25 TO 35 MPH WITH A
FEW PERIODS OF STRONGER WINDS IN THE MORNING HOURS AS THE INVERSION
BEGINS TO LIFT. GUSTS SHOULD REMAIN WITHIN THE 50 TO 55 MPH ZONE AS
WINDS JUST OFF THE SURFACE ARE PROGGED TO ONLY BE AS HIGH AS 40 KTS.
LASTLY FOR FRIDAY...LITTLE CHANGE TO THE AIRMASS OUT IN THE FAR
WESTERN PORTIONS OF THE FORECAST AREA ON FRIDAY MORNING SUGGESTS A
RETURN OF STRATUS AND PATCHY FOG IN FAR SOUTHWESTERN CARBON COUNTY.
WITH LITTLE CHANGE IN THE SYNOPTIC PATTERN ON SATURDAY...EXPECT
MODERATE WINDS TO CONTINUE THROUGH AT LEAST SATURDAY AFTERNOON. BREEZY
WEST-NORTHWEST WINDS WILL EXPAND WESTWARD AND JUST TO THE LEE OF THE
MOUNTAINS DURING THE AFTERNOON HOURS AS THE INVERSION LIFTS...WHICH
WILL WARM TEMPS ACROSS THE EASTERN PLAINS BACK INTO THE 50S FOR
FRIDAY AND SATURDAY DUE TO DOWNSLOPE WARMING EFFECTS. A WEAK
SHORTWAVE MOVING TOWARD THE REGION ON SATURDAY AFTERNOON WILL BRING
WITH IT A PLUME OF LOW-MID LEVEL MOISTURE. COULD SEE A FEW
OROGRAPHIC SNOW SHOWERS OVER THE MOUNTAINS IN THE LATE AFTERNOON AS
THIS WEAK ENERGY AND MOISTURE MOVE OVERHEAD.
.LONG TERM...(SATURDAY NIGHT THROUGH WEDNESDAY)
ISSUED AT 332 AM MST THU NOV 28 2013
VERY DEFINITE PATTERN CHANGE CONTINUES TO BE ADVERTISED IN THE
LONG TERM. LOOKS VERY COLD AND WET FOR NEXT WEEK.
STARTING OFF SATURDAY NIGHT...LOOKS LIKE OUR WIND PRONE AREAS WILL
BE WINDY AS GFS 700MB WINDS ARE UP AROUND 45KTS SATURDAY NIGHT.
AFTER A DECREASE IN WINDS DURING THE DAY SUNDAY...THEY PICK UP
AGAIN SUNDAY NIGHT...THOUGH NOT AS STRONG AS PREVIOUS MODEL RUNS
WERE ADVERTISING. RIGHT NOW...THE NEW GFS WINDS ARE RIGHT AROUND
45-50KTS SUNDAY EVENING INTO MONDAY. CRAIG TO CASPER 700MB HEIGHT
GRADIENT STILL TIGHT THOUGH...RIGHT AROUND 70MTRS...SO IF THIS
HOLDS TRUE...WE WILL PROBABLY NEED SOME WIND HEADLINES FOR THIS
TIME FRAME.
MODELS STILL ADVERTISING A DRASTIC CHANGE IN THE WEATHER TUESDAY
AS A STRONG PACIFIC LOW PRESSURE SYSTEM MOVES INTO THE PACNW.
FRONT DOES NOT MAKE IT INTO SOUTHEAST WYOMING UNTIL WEDNESDAY
MORNING. MODELS CONTINUE TO SHOW THIS FRONT STALLING OVER NORTHERN
COLORADO AND PERSISTING THROUGH THE REMAINDER OF THE WEEK. 700MB
TEMPERATURES ARE QUITE COLD BEHIND THE FRONT. GFS SHOWING -18 TO
-20C WHILE NEW ECMWF RUN SHOWING -16 TO -18C. GOING TO BE QUITE
COLD THROUGH THE REMAINDER OF THE WEEK. HIGHS THURSDAY/FRIDAY MAY
ONLY BE IN THE TEENS WITH LOWS CLOSE TO ZERO AT MANY LOCATIONS.
&&
.AVIATION...(FOR THE 18Z TAFS)
STRATUS ACROSS SOUTH DAKOTA AND CENTRAL/EASTERN NEBRASKA IS NOT
EXPECTED TO MOVE INTO THE NORTHERN NE PANHANDLE THIS
AFTERNOON...ALTHOUGH IT IS CLOSE TO KCDR AT THIS HOUR. WILL CONTINUE
TO MONITOR THE WESTWARD PROGRESSION OF THIS LOW CIG STRATUS.
OTHERWISE...LIGHT WINDS AND VFR CONDITIONS WILL CONTINUE ACROSS
SOUTHEAST WYOMING AND WESTERN NEBRASKA THROUGH TONIGHT.
&&
.FIRE WEATHER...
ISSUED AT 332 AM MST THU NOV 28 2013
NO FIRE WEATHER CONCERNS ANTICIPATED THROUGH THE NEAR TERM. MILD AND
DRY CONDITIONS WILL CONTINUE ACROSS THE DISTRICT OVER THE NEXT FEW
DAYS WITH DAYTIME TEMPS AVERAGING IN THE 40S AND 50S DEGREES...WITH
COOLER READINGS OVER THE HIGHER TERRAIN. MINIMUM HUMIDITIES WILL BE
AT OR ABOVE 30 PERCENT EACH AFTERNOON. MODERATE WINDS ARE EXPECTED
ON FRIDAY AND SATURDAY IN THE WIND PRONE REGIONS ALONG AND WEST OF
THE LARAMIE RANGE WITH SUSTAINED SPEEDS BETWEEN 25 AND 40 MPH AND
GUSTS AROUND 50 MPH AT TIMES. A STRONG WEATHER SYSTEM WILL BEGIN TO
TAKE SHAPE LATE THIS WEEKEND INTO THE EARLY PART OF NEXT
WEEK...LIKELY BRINGING STRONGER WINDS...COLDER TEMPERATURES AND AN
INCREASED CHANCE FOR ACCUMULATING SNOWS.
&&
.CYS WATCHES/WARNINGS/ADVISORIES...
WY...NONE.
NE...NONE.
&&
$$
SHORT TERM...RJM
LONG TERM...CLAYCOMB
AVIATION...TJT
FIRE WEATHER...RJM
AREA FORECAST DISCUSSION
NWS CHEYENNE WY
333 AM MST THU NOV 28 2013
.SHORT TERM...(TODAY THROUGH SATURDAY)
ISSUED AT 332 AM MST THU NOV 28 2013
10Z SURFACE ANALYSIS SHOWS THE COLD FRONT BISECTING THE CWA FROM
NORTHWEST TO SOUTHEAST WITH LIGHT WINDS THROUGHOUT THE AREA. HIGH
CLOUDS ARE STREAMING OVERHEAD IN NORTHWEST FLOW WITH A STRATUS DECK
CREEPING SOUTH-SOUTHWESTWARD ACROSS THE CENTRAL PLAINS AND TOWARD
THE NORTHERN NEBRASKA PANHANDLE. CURRENT TRENDS COMBINED WITH NAM
BUFKIT SOUNDINGS AND RECENT HRRR RUNS SUGGEST THAT THIS STRATUS DECK
WILL IMPACT CHADRON AROUND SUNRISE AND MAY SNEAK INTO ALLIANCE AS
WELL THROUGH THE MORNING. GUIDANCE ALSO SUGGESTS THE LOW CLOUDS WILL
PERSIST THROUGH THE MORNING...AND WILL SCATTER OUT SLOWLY WITH
INCREASED SOLAR INSOLATION. IN ADDITION...SOUTHEASTERLY WINDS WILL
BECOME BREEZY ACROSS THE EASTERN PLAINS AS THE SFC HIGH SLIDES
SOUTH-SOUTHEAST ACROSS THE CENTRAL PLAINS. THIS WILL ADVECT SOME
LLVL MOISTURE INTO THE EASTERN PLAINS AND LIKELY CONTRIBUTE TO THE
SLOWER MIXING OUT OF THE STRATUS. INCREASED CLOUD COVER FOR TODAY IN
THIS AREA AS A RESULT...AND LOWERED MAX TEMPS A FEW DEGREES DUE TO THE
MORE PERSISTENT CLOUD DECK. OTHERWISE...EXPECTING A DRY...CALM
THANKSGIVING DAY WITH LIGHT WINDS AND CONTINUAL HIGH CIRRUS MOVING
OVERHEAD FROM THE NORTHWEST.
TONIGHT...A SHORTWAVE WILL MOVE EASTWARD ACROSS CENTRAL CANADA WHILE
A SECOND WEAK WAVE WILL MOVE ACROSS COLORADO. THE COMBINATION OF
FEATURES WILL DEEPEN THE LEESIDE SFC PRESSURE TROUGH...ALTHOUGH THE
DEEPEST PRESSURE FALLS WILL REMAIN WELL REMOVED FROM THE REGION AND
THEREFORE THE SFC PRESSURE GRADIENT WILL NOT BECOME VERY STRONG.
STILL LOOKING AT 850/700 MB CAG-CPR GRADIENTS OF 30 DAM OR LESS BY
EARLY FRIDAY MORNING. A LOOK AT A CROSS SECTION OF LAPSE RATES AND
WINDS THROUGH THE WIND PRONE REGIONS ALONG AND WEST OF THE LARAMIE
RANGE SHOWS THE INCREASE IN WINDS WITH THE STRENGTHENING
GRADIENT...BUT THE INVERSION REMAINS NEAR THE GROUND EARLY FRIDAY
MORNING WHICH SHOULD MINIMIZE GAP EFFECTS. THE INVERSION WILL LIFT
JUST OFF THE SURFACE AND WILL REMAIN RELATIVELY WEAK THROUGH
FRIDAY...BUT SHOULD BE STRONG ENOUGH TO PRODUCE MODERATE
GRADIENT/GAP WINDS THROUGH FRIDAY NIGHT. LOOKING AT SUSTAINED
WEST-SOUTHWEST WINDS IN THIS AREA ON AVERAGE OF 25 TO 35 MPH WITH A
FEW PERIODS OF STRONGER WINDS IN THE MORNING HOURS AS THE INVERSION
BEGINS TO LIFT. GUSTS SHOULD REMAIN WITHIN THE 50 TO 55 MPH ZONE AS
WINDS JUST OFF THE SURFACE ARE PROGGED TO ONLY BE AS HIGH AS 40 KTS.
LASTLY FOR FRIDAY...LITTLE CHANGE TO THE AIRMASS OUT IN THE FAR
WESTERN PORTIONS OF THE FORECAST AREA ON FRIDAY MORNING SUGGESTS A
RETURN OF STRATUS AND PATCHY FOG IN FAR SOUTHWESTERN CARBON COUNTY.
WITH LITTLE CHANGE IN THE SYNOPTIC PATTERN ON SATURDAY...EXPECT
MODERATE WINDS TO CONTINUE THROUGH AT LEAST SATURDAY AFTERNOON. BREEZY
WEST-NORTHWEST WINDS WILL EXPAND WESTWARD AND JUST TO THE LEE OF THE
MOUNTAINS DURING THE AFTERNOON HOURS AS THE INVERSION LIFTS...WHICH
WILL WARM TEMPS ACROSS THE EASTERN PLAINS BACK INTO THE 50S FOR
FRIDAY AND SATURDAY DUE TO DOWNSLOPE WARMING EFFECTS. A WEAK
SHORTWAVE MOVING TOWARD THE REGION ON SATURDAY AFTERNOON WILL BRING
WITH IT A PLUME OF LOW-MID LEVEL MOISTURE. COULD SEE A FEW
OROGRAPHIC SNOW SHOWERS OVER THE MOUNTAINS IN THE LATE AFTERNOON AS
THIS WEAK ENERGY AND MOISTURE MOVE OVERHEAD.
.LONG TERM...(SATURDAY NIGHT THROUGH WEDNESDAY)
ISSUED AT 332 AM MST THU NOV 28 2013
VERY DEFINITE PATTERN CHANGE CONTINUES TO BE ADVERTISED IN THE
LONG TERM. LOOKS VERY COLD AND WET FOR NEXT WEEK.
STARTING OFF SATURDAY NIGHT...LOOKS LIKE OUR WIND PRONE AREAS WILL
BE WINDY AS GFS 700MB WINDS ARE UP AROUND 45KTS SATURDAY NIGHT.
AFTER A DECREASE IN WINDS DURING THE DAY SUNDAY...THEY PICK UP
AGAIN SUNDAY NIGHT...THOUGH NOT AS STRONG AS PREVIOUS MODEL RUNS
WERE ADVERTISING. RIGHT NOW...THE NEW GFS WINDS ARE RIGHT AROUND
45-50KTS SUNDAY EVENING INTO MONDAY. CRAIG TO CASPER 700MB HEIGHT
GRADIENT STILL TIGHT THOUGH...RIGHT AROUND 70MTRS...SO IF THIS
HOLDS TRUE...WE WILL PROBABLY NEED SOME WIND HEADLINES FOR THIS
TIME FRAME.
MODELS STILL ADVERTISING A DRASTIC CHANGE IN THE WEATHER TUESDAY
AS A STRONG PACIFIC LOW PRESSURE SYSTEM MOVES INTO THE PACNW.
FRONT DOES NOT MAKE IT INTO SOUTHEAST WYOMING UNTIL WEDNESDAY
MORNING. MODELS CONTINUE TO SHOW THIS FRONT STALLING OVER NORTHERN
COLORADO AND PERSISTING THROUGH THE REMAINDER OF THE WEEK. 700MB
TEMPERATURES ARE QUITE COLD BEHIND THE FRONT. GFS SHOWING -18 TO
-20C WHILE NEW ECMWF RUN SHOWING -16 TO -18C. GOING TO BE QUITE
COLD THROUGH THE REMAINDER OF THE WEEK. HIGHS THURSDAY/FRIDAY MAY
ONLY BE IN THE TEENS WITH LOWS CLOSE TO ZERO AT MANY LOCATIONS.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z FRIDAY MORNING)
ISSUED AT 332 AM MST THU NOV 28 2013
SOME CONCERN FOR THE NORTHERN NEBRASKA PANHANDLE AS LATEST 11-3.9U
SATELLITE IMAGERY SHOWING LOW STRATUS MOVING SOUTHWEST OUT OF
SOUTH DAKOTA. LATEST HRRR MODEL BRINGS IFR CONDITIONS INTO KCDR
AND KEEPS IT IN THROUGH 18Z. WILL BE ADJUSTING THE 12Z KCDR TAF
BASED ON THIS AND THE SATELLITE TRENDS ONCE THE STRATUS GETS CLOSER.
&&
.FIRE WEATHER...
ISSUED AT 332 AM MST THU NOV 28 2013
NO FIRE WEATHER CONCERNS ANTICIPATED THROUGH THE NEAR TERM. MILD AND
DRY CONDITIONS WILL CONTINUE ACROSS THE DISTRICT OVER THE NEXT FEW
DAYS WITH DAYTIME TEMPS AVERAGING IN THE 40S AND 50S DEGREES...WITH
COOLER READINGS OVER THE HIGHER TERRAIN. MINIMUM HUMIDITIES WILL BE
AT OR ABOVE 30 PERCENT EACH AFTERNOON. MODERATE WINDS ARE EXPECTED
ON FRIDAY AND SATURDAY IN THE WIND PRONE REGIONS ALONG AND WEST OF
THE LARAMIE RANGE WITH SUSTAINED SPEEDS BETWEEN 25 AND 40 MPH AND
GUSTS AROUND 50 MPH AT TIMES. A STRONG WEATHER SYSTEM WILL BEGIN TO
TAKE SHAPE LATE THIS WEEKEND INTO THE EARLY PART OF NEXT
WEEK...LIKELY BRINGING STRONGER WINDS...COLDER TEMPERATURES AND AN
INCREASED CHANCE FOR ACCUMULATING SNOWS.
&&
.CYS WATCHES/WARNINGS/ADVISORIES...
WY...NONE.
NE...NONE.
&&
$$
SHORT TERM...RJM
LONG TERM...CLAYCOMB
AVIATION...CLAYCOMB
FIRE WEATHER...RJM
AREA FORECAST DISCUSSION
NWS GRAND FORKS ND
337 AM CST SAT NOV 30 2013
.SHORT TERM...(TODAY THROUGH SUNDAY)
ISSUED AT 337 AM CST SAT NOV 30 2013
00Z MODELS INITIALIZED WITH MINIMAL ERRORS AND ARE IN GOOD
AGREEMENT THROUGH SUNDAY. THE CHALLENGE FOR TODAY WILL BE
TEMPERATURES AND CLOUD COVER. THE CHALLENGE FOR SUNDAY WILL BE -SN
CHANCES.
TODAY-TONIGHT...WEAK COLD FRONT WILL BE THROUGH THE REGION WHICH
SHOULD LEAD TO SLIGHTLY COOLER TEMPERATURES THAN YESTERDAY. THE
MID-LEVEL CLOUDS ALONG AND AHEAD OF THIS FEATURE WILL MOVE
SOUTH...BUT WILL NEED TO WATCH THE LOW-LEVEL CIGS APPROACHING FROM
THE NORTH. 06Z RAP IS MOST AGGRESSIVE BRINGING THESE CIGS INTO THE
ENTIRE FA...WHILE MOST OTHER GUIDANCE SUGGESTS ONLY PORTIONS OF NW
MN WILL BE AFFECTED. WILL SIDE WITH THE MAJORITY...AND TAKE A
CLOSER LOOK AT THE 7AM UPDATE.
SUNDAY...00Z MODELS HAVE SLOWED THE SHORTWAVE BRINGING -SN
CHANCES...ADJUSTED POPS ACCORDINGLY. MUCH OF SUNDAY SHOULD BE DRY
(UNTIL THE EVENING HOURS).
.LONG TERM...(SUNDAY NIGHT THROUGH FRIDAY)
ISSUED AT 337 AM CST SAT NOV 30 2013
SUNDAY NIGHT-MONDAY NIGHT...00Z MODELS BEGIN TO DIVERGE...WITH THE
ECMWF/GEM/UKMET DIGGING THE UPPER LOW INTO THE NW CONUS BY 12Z
TUE...AND THE NAM/GFS BRINGING THIS FEATURE INTO MONTANA/WESTERN
DAKOTAS. THE ECMWF/GEM/UKMET HAVE BEEN THE MORE CONSISTENT
MODELS...AND ARE SUPPORTED BY ENSEMBLES (WILL FOLLOW FOR FORECAST
DETAILS). THERE WILL BE A COUPLE LEAD SHORTWAVES EJECTING FROM THE
MAIN UPPER TROUGH. THE FIRST WILL MOVE THROUGH THE REGION SUNDAY
NIGHT...AND THE SECOND MONDAY AFTERNOON/NIGHT. SINCE THERE HAVE
BEEN A FEW MODEL RUNS INDICATING THESE FEATURES...WILL INCREASE
POPS TO LIKELY AND ATTEMPT TO TIME THESE FEATURES THROUGH THE
REGION. THE FIRST WAVE IS WEAKER...AND SHOULD HAVE LESS AVAILABLE
MOISTURE. MESOSCALE FORCING IS ALSO WEAK...SO UP TO AN INCH OF
SNOWFALL APPEARS POSSIBLE (MAYBE 2 INCHES). THE SECOND WAVE IS
STRONGER...WITH MORE AVAILABLE MOISTURE (PWATS APPROACHING 0.5
INCHES). MODELS INDICATE A DEFINED CIRCULATION AT 850MB (AND A
WEAK 700MB LOW) PROPAGATING FROM NW ND INTO SE ND ON
MONDAY...LOSING DEFINITION MONDAY NIGHT AS IT PROPAGATES FURTHER
TO THE SE. ASSOCIATED WARM AIR ADVECTION/DEFORMATION COMBINED
WITH THE 0.5 INCH PWATS SHOULD LEAD TO A FEW INCHES OF SNOWFALL.
MODELS INDICATE 0.25-0.40 INCHES QPF ACROSS ALL BUT THE NE
FA...AND COMBINED WITH 12:1-13:1 SNOW RATIOS WOULD LEAD TO AN AREA
OF 3-5 INCHES OF SNOW. P-TYPE WILL BE ALL SNOW IF THE EXPECTED
SOLUTION VERIFIES. THE NAM/SREF/GFS HAVE WARMER MID-LEVEL
TEMPERATURES SINCE THE UPPER WAVE IS CLOSER TO THE REGION (LOW
LEVEL SOUTHERLY FLOW IS STRONGER)...AND WOULD LEAD TO FZRA/RA
POTENTIAL (BUT THIS PROBABILITY SEEMS VERY LOW ATTM).
TUESDAY-FRIDAY...A VERY WINTRY PERIOD IS IN STORE...WITH THE MAIN
FOCUS INITIALLY BEING SNOW POTENTIAL THROUGH MID-WEEK FOLLOWED BY
A COLD ARCTIC AIR MASS SPILLING SOUTH.
MODEL SPREAD CONTINUES TO BE SIGNIFICANT...ALTHOUGH THE ECMWF HAS
SHOWN BETTER CONSISTENCY OVER THE PAST FEW RUNS...SO HAVE TRENDED A
BIT IN THAT DIRECTION. THE 00Z GFS/ECMWF BOTH BRING THE UPPER TROUGH
EASTWARD INTO THE PLAINS WED/THU. HOWEVER...A CHALLENGE CONTINUES TO
BE TIMING OF EMBEDDED WAVES. THE ECMWF REMAINS DEEPEST AND FARTHEST
WEST WITH SFC LOW DEVELOPMENT FROM THE CENTRAL PLAINS NORTHEAST INTO
ONTARIO IN CONJUNCTION WITH A STRONG SHORTWAVE TROUGH ASSOCIATED
WITH THE LIFTING UPPER LOW...WHILE THE GFS IS MORE PROGRESSIVE WITH
A WEAKER SFC LOW ASSOCIATED WITH A LEAD WAVE. THUS...THE ECMWF AND
TO A LESSER EXTENT THE GEM ARE MORE AGGRESSIVE WITH QPF. THE 500 MB
GFS ENSEMBLE MEAN HEIGHT FIELD GENERALLY SUPPORTS THE ECMWF BROADLY.
CONFIDENCE STILL IS RATHER LOW REGARDING THE PLACEMENT AND MAGNITUDE
OF SNOWFALL...ALTHOUGH THE MID-WEEK PERIOD WILL CONTINUE TO BEAR
WATCHING FOR ACCUMULATING SNOWFALL.
ARCTIC AIR WILL BLAST SOUTH DURING THE LATTER PART OF THE
WEEK INTO NEXT WEEKEND. THE ECMWF CONTINUES TO INDICATE 925 MB TEMPS
DOWN TO -20 TO -25C THURSDAY/FRIDAY BEHIND INITIAL SURGE OF COLD
ADVECTION. BLUSTERY WINDS WILL COMBINE WITH VERY COLD TEMPS TO
PRODUCE POTENTIALLY HAZARDOUS WIND CHILLS AT TIMES.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SATURDAY NIGHT)
ISSUED AT 1146 PM CST FRI NOV 29 2013
SATELLITE AND SURFACE OBS INDICATE CIGS ABOVE 9 THOUSAND FT WERE
LOCATED OVER NORTHERN ND AND PARTS OF SOUTHEAST ND. MID LEVEL DECK
SHOULD CONTINUE TO MOVE SOUTHEAST THROUGH THE AREA TONIGHT AND SAT.
ALSO CLEAR SLOT OVER SOUTHERN SASK AND SOUTHWEST MAN CONTINUES TO
MOVE SOUTHEAST. ELSEWHERE CIGS AROUND 35 HUNDRED FT WERE LOCATED OVER
THE FAR NORTHEAST ZONES AND MAY CONTINUE THERE FOR THE REST OF THE
NIGHT.
&&
.FGF WATCHES/WARNINGS/ADVISORIES...
ND...NONE.
MN...NONE.
&&
$$
SHORT TERM...TG
LONG TERM...TG/MAKOWSKI
AVIATION...HOPPES
AREA FORECAST DISCUSSION
NWS ABERDEEN SD
349 AM CST SAT NOV 30 2013
.SHORT TERM...TODAY THROUGH MONDAY
CHANCES FOR PRECIPITATION AS WELL AS P-TYPE WILL BE THE FORECAST
CHALLENGES.
A WEAK MID LEVEL SHORT WAVE CURRENTLY OVER MONTANA WILL TRACK
SOUTHEASTWARD ACROSS THE REGION TODAY...BRINGING PARTLY CLOUDY
SKIES TO THE CWA. THE PAST FEW RUNS OF THE RUC AND THE NSSL WRF
BOTH SHOW SOME LIGHT RAIN FOR THE FAR NW PORTION OF THE
CWA...PERHAPS REACHING KMBG BY THIS AFTERNOON. THUS HAVE ADDED A
LOW POP.
ANOTHER MID LEVEL SHORT WAVE AND FRONTAL BOUNDARY WILL TRACK
ACROSS THE REGION ON SUNDAY. MODELS HAVE SIGNIFICANTLY SLOWED DOWN
THE PROGRESSION OF THE TROUGH...WITH PCPN NOT REACHING THE JAMES
RIVER VALLEY UNTIL AFTER 18Z. IT STILL APPEARS AS THOUGH THE
LEADING EDGE OF THE PCPN WILL FALL AS ALL SNOW. HOWEVER WITH WAA
QUICKLY PUSHING IN ON THE BACK SIDE...THE SNOW WILL TRANSITION
OVER TO ALL RAIN. THIS SYSTEM DOES NOT CONTAIN A GREAT DEAL OF LOW
LEVEL MOISTURE SO WILL MAINTAIN CHC POP ALONG THE ND/SD BORDER FOR
NOW. A MUCH STRONGER STORM SYSTEM WILL BEGIN IMPACTING THE REGION
ON MONDAY. HOWEVER MODEL ARE NOT IN A REAL GOOD AGREEMENT WITH THE
OVERALL PLACEMENT OF THIS MID LEVEL CLOSED LOW...WHICH LEADS TO A
LOW FORECASTER CONFIDENCE. EVEN WITH A DISAGREEMENT ON THE PLACEMENT
THERE IS A GENERAL CONSENSUS THAT TEMPERATURES WILL BE WARM ENOUGH
TO SUPPORT A MOSTLY RAIN EVENT.
.LONG TERM...MONDAY NIGHT THROUGH FRIDAY
STILL NOT A LOT OF CONFIDENCE WITH THE FINER DETAILS WITHIN THE
EXTENDED...THOUGH TWO GENERAL TRENDS CAN BE EXPECTED. THE FIRST
WILL BE THE INFLUENCE OF A BROAD UPPER TROF AND EMBEDDED
SHORTWAVES MOVING ACROSS THE NORTHERN TIER CONUS. MOST OF THE
PRECIPITATION WILL BE ASSOCIATED WITH AN H7 LOW THAT LOOKS TO
TRACK ACROSS NORTH DAKOTA/MINNESOTA...THOUGH IT MAY PIVOT THROUGH
WESTERN SOUTH DAKOTA DEPENDING ON THE MODEL. THIS TRACK SUGGESTS
NORTH DAKOTA WILL RECEIVE THE MAJORITY OF PRECIPITATION WITHIN THE
WARM ADVECTION BAND AND ANY TROWAL BASED WRAP AROUND. THE GFS IS
GENERALLY WEAKER WITH SIGNIFICANTLY LOWER PRECIPITATION POTENTIAL.
THE ECMWF IS STRONGER...WITH A MORE SOUTHERLY TRACK...AND STRONGER
WINDS WITH POTENTIALLY MORE IMPACTS TO THE CWA.
THE SECOND FEATURE WILL BE ANOMALOUSLY COLD AIR POURING INTO THE
REGION. TIMING DIFFERENCES CONTINUE BETWEEN THE GFS AND
ECMWF...VARYING BETWEEN TUESDAY AND WEDNESDAY RESPECTIVELY. BOTH
MODELS RESOLVE THE COLD POOL WITH SIMILAR INTENSITY AND
DURATION...AS IT WILL COME TO DOMINATE THE WEATHER THROUGH THE END
OF THE WORK WEEK.
UNFORTUNATELY...BOTH MODELS HAVE BEEN REASONABLY CONSISTENT WITH
THEIR INDIVIDUAL TRENDS. WILL CONTINUE TO BROADBRUSH THE FIRST FEW
PERIODS OF THE EXTENDED WITH CHANCE POPS/SNOW UNTIL MODELS ENTER
BETTER ALIGNMENT.
&&
.AVIATION...
06Z TAFS FOR THE KABR...KATY...KPIR AND KMBG TERMINALS
VFR CONDITIONS WILL CONTINUE THROUGH THE PERIOD. LIGHT WINDS WILL
PERSIST OVERNIGHT BEFORE SWITCHING TO NORTH-NORTHWEST AROUND 5 TO
10 KNOTS ON SATURDAY.
&&
.ABR WATCHES/WARNINGS/ADVISORIES...
SD...NONE.
MN...NONE.
&&
$$
SHORT TERM...SD
LONG TERM...CONNELLY
AVIATION...DORN
WEATHER.GOV/ABERDEEN
AREA FORECAST DISCUSSION
NWS BLACKSBURG VA
1226 AM EST SAT NOV 30 2013
.SYNOPSIS...
HIGH PRESSURE WILL BE ACROSS THE REGION THROUGH THE WEEKEND WHILE
A SERIES OF UPPER LEVEL DISTURBANCES PASS NORTH OF THE REGION. A
WEAK DISTURBANCE WILL PASS THROUGH THE AREA ON MONDAY WHILE AN
AREA OF LOW PRESSURE MOVES NORTH ALONG THE COAST. THE NEXT SYSTEM
TO BRING PRECIPITATION TO MOST OF OUR REGION WILL ARRIVE THURSDAY
INTO FRIDAY.
&&
.NEAR TERM /THROUGH TODAY/...
AS OF 920 PM EST FRIDAY
ADJUSTED OVERNIGHT MIN TEMPS DOWN A FEW DEGREES AS SKIES REMAIN
CLEAR SO FAR WITH CALMS WINDS NEARLY EVERYWHERE. STILL HOLDING TO
IDEA OF LOW CLOUDS DRIFTING SW ACROSS THE MOUNTAINS BY THE EARLY
MORNING HOURS AS SHOWN BY LATEST RAP AND NAM MODELS WHICH WOULD
ARREST THE DOWNWARD TRAJECTORY IN TEMPS SOMEWHAT. LOWERED WINDS
SLIGHTLY AS WELL BUT OTHERWISE NO SUBSTANTIVE CHANGES.
PREVIOUS VALID DISCUSSION
AS OF 300 PM EST FRIDAY...
A WEAK UPPER LEVEL DISTURBANCE WILL PROGRESS THROUGH THE GREAT LAKES
REGION TONIGHT INTO SATURDAY. SURFACE HIGH PRESSURE WILL BECOME
CENTERED OVER NEW ENGLAND BY SATURDAY MORNING...AND ITS ASSOCIATED
RIDGE AXIS WILL TRAIL SOUTHWEST ALONG THE LEE OFF THE APPALACHIANS.
LOW LEVEL MOISTURE HAS BEEN ABUNDANT TODAY FROM NORTHERN WEST
VIRGINIA...NORTH INTO PENNSYLVANIA.
TWO WEATHER PATTERNS WILL CONTRIBUTE TO INCREASING CLOUD COVER
TONIGHT INTO SATURDAY. FIRST...THE ADVANCING SYSTEM THROUGH THE
GREAT LAKES REGION HAS ALREADY ALLOWED FOR SOME DOWNSTREAM
ADVANCEMENT OF MID TO HIGH LEVEL CLOUD COVER OVER PARTS OF INDIANA
AND KENTUCKY. THIS CLOUD COVER WILL PROGRESS INTO OUR REGION
OVERNIGHT WITH INCREASING COVERAGE THROUGH SATURDAY. THE GREATEST
CONCENTRATION WILL OVER THE NORTHERN PARTS OF THE FORECAST AREA.
SECOND...BOTH 12Z/7AM GFS AND TO A GREATER DEGREE THE 12Z/7AM NAM
ARE DEPICTING A SOUTHERN ADVANCEMENT OF THE WV/MD/PA MOISTURE ALONG
THE LEE OF THE APPALACHIANS OVERNIGHT. THIS MOISTURE IS DEPICTED AS
BEING SHALLOW WITHIN ROUGHLY THE 925-900 MB LAYER. 925 MB WINDS WILL
BE COMPARABLE TO THE ORIENTATION TYPICALLY ASSOCIATED WITH ONSET OF
A HIGH PRESSURE RIDGE ALONG COMMON DAMMING AREA. 925 MB WINDS WILL
GRADUALLY VEER OVERNIGHT TO NORTHEAST AND THEN TO THE EAST. THE
WV/MD/PA MOISTURE IS PROGGED TO GET CAUGHT UP IN THIS FLOW AND
EVENTUALLY TAKE AN UPSLOPE ORIENTATION TO THE BLUE RIDGE. THIS WILL
HELP IN THE FORMATION OF LOW LEVEL CLOUD COVER ACROSS THOSE REGIONS
OF THE FORECAST AREA GENERALLY ALONG AND WEST OF THE CREST OF THE
BLUE RIDGE. THE WINDOW OF BEST COVERAGE WILL BE FROM ROUGHLY 300 AM
SATURDAY THROUGH 10AM SATURDAY. PAST THIS POINT THE NOCTURNAL
INVERSION WILL HAVE ERODED AND THE CLOUDS BEGIN TO DISSIPATE. FOR
LOWS TONIGHT...I HAVE FAVORED NUMBERS AT OR SLIGHTLY ABOVE GUIDANCE
IN THOSE AREAS THAT WILL EXPERIENCE THE BULK OF THE AFOREMENTIONED
CLOUD COVER.
FOR SATURDAY...THE REGION WILL STILL BE CONTENDING WITH THE MID TO
HIGH LEVEL CLOUD COVER...AGAIN PRIMARILY IN THE NORTH...IN
ASSOCIATION WITH PASSING SHORTWAVE TROUGH TO OUR NORTH. CLOSER TO THE
SURFACE...THE 925 MB FLOW BECOMES EASTERLY THE WHOLE WAY TO THE
COAST. THIS WILL ALLOW ATLANTIC MOISTURE TO PROGRESS INTO AT LEAST
THE PIEDMONT REGION OF THE FORECAST AREA BY THE LATE AFTERNOON. WILL
BE SHOWING INCREASING CLOUD COVER IN THIS REGION TO ACCOUNT FOR
THIS. HAVE NOT DEVIATED TOO FAR FROM A BLEND OF THE GFS AND NAM MOS
FOR HIGH TEMPERATURES.
&&
.SHORT TERM /TONIGHT THROUGH MONDAY NIGHT/...
AS OF 240 PM EST FRIDAY...
ZONAL FLOW ALOFT OVER THE MID APPALACHIAN AND MID ATLANTIC REGION
WILL GRADUALLY BE REPLACED BY MEAN TROFING OVER THE EASTERN PORTION
OF THE NATION BY THE END OF THE SHORT TERM PERIOD AS A SERIES OF
WEAK SHORT WAVE TROFS EMBEDDED IN NORTHERN STREAM HELPS TO SLOWLY
BUCKLE UPPER FLOW.
PRESENCE OF WEAK SURFACE HIGH PRESSURE...NEGLIGIBLE THERMAL
ADVECTION...AND PRESENCE OF HIGH AND OCCASIONALLY MID LEVEL CLOUDS
UNDER REGION OF CHANNELIZED VORTICITY SHOULD MAINTAIN RATHER
UNEVENTFUL WEATHER OVER THE BLACKSBURG FORECAST AREA SATURDAY NIGHT
THROUGH SUNDAY NIGHT WITH SOMEWHAT MODERATED DIURNAL TEMPERATURE
PROFILE. NIGHTTIME LOWS EXPECTED TO RANGE FROM THE MID 20S TO LOWER
30S IN MOST AREAS...WITH COOLEST READINGS IN THE DEEPER VALLEYS...
AND MILDER READINGS ACROSS THE RIDGELINES AND NC FOOTHILLS. DAYTIME
HIGHS ON SATURDAY EXPECTED TO RANGE FROM THE LOWER TO MID 40S IN THE
MOUNTAINS TO LOWER 50S ACROSS THE PIEDMONT.
A MORE SIGNIFICANT SHORT WAVE IS EXPECTED TO AMPLIFY UPPER FLOW AS
IT DIVES EAST-SOUTHEAST OUT OF THE MISSISSIPPI VALLEY ON
MONDAY...REACHING THE EAST COAST BY LATE MONDAY NIGHT. BACKING FLOW
ALOFT WILL HELP STRENGTHEN BAROCLINIC ZONE ALONG THE SOUTHEAST
COAST...RESULTING IN CYCLOGENESIS WITH SURFACE LOW EXPECTED TO
DEVELOP AND STRENGTHEN ALONG THE COAST BY LATE IN SHORT TERM PERIOD.
MID-RANGE MODELS NOT YET CONSISTENTLY RESOLVING DEVELOPMENT...
PLACEMENT...AND TIMING OF THIS FEATURE...YET MOST IMPLY THAT FLOW
WILL NOT AMPLIFY SUFFICIENTLY OR SOON ENOUGH TO ALLOW DEVELOPING
AREA OF PRECIPITATION IN ISENTROPIC ZONE TO SIGNIFICANTLY THREATEN
BLACKSBURG AREA OF CONCERN BEFORE MOVING OFF THE EAST.
CONSIDERING THAT PAST COUPLE OF MODEL TRENDS HAVE BECOME A BIT MORE
BULLISH IN AMPLIFICATION OF THIS SYSTEM...WILL CONTINUE TO MAINTAIN A
LOW THREAT FOR PRECIPITATION IN MOST AREAS MONDAY AFTERNOON INTO
MONDAY NIGHT...WITH HIGHEST THREAT FOR PRECIPITATION EXPECTED TO BE
RESTRICTED TO MAINLY NORTHWESTERN MOUNTAINS WHERE LOCAL UPSLOPING
WILL BE MAXIMIZED.
CONSIDERING THERMAL PROFILE...ANY PRECIPITATION ON MONDAY WILL
LIKELY COME IN THE FORM OF SPOTTY LIGHT SHOWERS...HOWEVER INCREASING
COLD ADVECTION ON BACKSIDE OF COASTAL LOW WILL LIKELY BE/BECOME
SUFFICIENT ENOUGH TO ALLOW CHANGEOVER TO SNOW OR RAIN/SNOW MIX IN
MOUNTAINS ON MONDAY NIGHT. FURTHER EAST...EVEN IF COASTAL LOW IS
ABLE TO CRANK UP FAST ENOUGH TO PUSH PRECIPITATION UNDER DEVELOPING
DEFORMATION ZONE WESTWARD INTO EASTERN PIEDMONT COUNTIES...THERMAL
PROFILE IN THAT AREA LIKELY TO REMAIN ABOVE FREEZING (HENCE ONLY A
COLD RAIN) UNTIL SYSTEM LIFTS AWAY FROM THE AREA BY/BEFORE DAYBREAK
TUESDAY.
&&
.LONG TERM /TUESDAY THROUGH FRIDAY/...
AS OF 300 PM EST FRIDAY...
THE BEGINNING OF THE LONG TERM PERIOD WILL BEGIN WITH SOME UPSLOPE
PRECIPITATION ACROSS THE MOUNTAINS. BOTH THE GFS AND THE ECMWF SHOW
PRECIPITATION THROUGH ABOUT 6Z WEDNESDAY. LIKELY WILL BE SNOW
SHOWERS ACROSS WESTERN GREENBRIER WITH A MIX OF RAIN AND SNOW ACROSS
LOWER ELEVATION MOUNTAIN AREAS. MODELS ALSO AGREE THAT THERE WILL
CONTINUE TO BE A GENERAL WARMING TREND AS 500 MB HEIGHT LEVELS
CONTINUE TO RISE THROUGH THE WEEK. FROM THURSDAY ON THROUGH SATURDAY
850MB TEMPS WILL BE +5-10C. THIS SHOULD ALLOW DAYTIME MAX TEMPS TO
EASILY REACH THE 50S AND EVEN LOWER 60S EAST OF THE BLUE RIDGE BY
THE END OF THE WEEK.
WHILE WE WILL BE WARMER...A STRONG COLD FRONT WILL BEGIN TO APPROACH
THE REGION ON THURSDAY AND FRIDAY. BOTH THE GFS AND ECMWF BRING
MOISTURE IN AHEAD OF THE FRONT. CHANCE SHOWERS ARE MENTIONED FROM
THURSDAY THROUGH THE REST OF THE LONG TERM PERIOD ON 12Z SATURDAY.
LOOKING BEYOND SATURDAY...A DEEP TROUGH ACROSS THE WESTERN UNITED
STATES WILL BRING PLENTY OF COLD AIR FROM CANADA ALL THE WAY INTO
THE CENTRAL PLAINS. BY THE END OF THE 240HR MODEL RUN OUR REGION
CONTINUES TO BE UNDER THE INFLUENCE OF THE RIDGE AND THUS WILL STAY
ON THE WARMER SIDE. A CLOSER EYE WILL BE PAID TO FUTURE MODEL RUNS
TO SEE HOW THE PATTERN PROGRESSES.
&&
.AVIATION /05Z SATURDAY THROUGH WEDNESDAY/...
AS OF 1210 AM EST SATURDAY...
VFR CONDITIONS EXPECTED DURING MUCH OF THIS PERIOD. PREVIOUS
FORECASTS WERE THINKING SOME MVFR CIGS AT BLF/LWB/BCB. 00Z
SOUNDING AT RNK...FORECAST MODEL SOUNDINGS AND SATELLITE SHOW NO
INDICATION THAT LOWER CIGS WILL BE DEVELOP DUE TO DRY AIR. WILL GO
WITH SCT020 AROUND 09Z...BUT CONFIDENCE IS HIGH THAT MVFR CIGS
WILL NOT FORM.
HIGH PRESSURE WEDGED SOUTHWARD ACROSS THE MID ATLANTIC INTO THE
CAROLINAS WITH TIGHER GRADIENT OVER THE MTNS WILL LEAD TO SOME
GUSTS TO 20-25 KNOTS AT BLF EARLY BEFORE RELAXING.
MVFR CIGS ARE POSSIBLE SATURDAY AFTERNOON AND EVENING IN THE
PIEDMONT AS LOW LEVEL WINDS VEER MORE EASTERLY AND WE START TO
TAP ATLANTIC MOISTURE INTO THE REGION. BY LATE SATURDAY NIGHT LOW
LEVEL WINDS ARE EXPECTED TO HAVE VEERED SOUTHWEST...AND WE LOSE
THE UPLSOPE COMPONENT RESPONSIBLE FOR THE MVFR CLOUDS. WITH
CONFIDENCE IN THIS REMAINING LOW WILL ONLY HAVE FEW-SCT MVFR AT
DAN/LYH.
SUNDAY INTO MONDAY MAINLY VFR CONDITIONS ARE EXPECTED AS WE BECOME
POSITIONED BETWEEN A LOW MOVING NORTH ALONG THE COAST AND A TROUGH
AXIS OVER THE OH/TN VALLEY. ISOLATED TO SCATTERED RAIN/SNOW
SHOWERS WILL BE POSSIBLE BY MONDAY NIGHT AS THE TROUGH APPROACHES
FROM THE WEST.
TUESDAY INTO WEDNESDAY MAINLY VFR CONDITIONS ARE EXPECTED AS THE
TROUGH PASSES TO OUR EAST AND AN AREA OF LOW PRESSURE DEVELOPS OFF
THE COAST. OUR REGION WILL BE LEFT IN A NORTHWEST FLOW PATTERN
WITH THE POTENTIAL FOR UPSLOPE CLOUDS OVER THE MOUNTAINS. THERE
MAY BE PATCHY MVFR CIGS WITHIN THESE.
&&
.RNK WATCHES/WARNINGS/ADVISORIES...
VA...NONE.
NC...NONE.
WV...NONE.
&&
$$
SYNOPSIS...DS
NEAR TERM...DS/PC
SHORT TERM...WERT
LONG TERM...CF
AVIATION...DS/PC/WP
AREA FORECAST DISCUSSION
NWS MELBOURNE FL
925 AM EST SAT NOV 30 2013
.DISCUSSION...
CURRENT-THIS AFTERNOON...FIRST COUPLE OF VISIBLE SATELLITE IMAGES
SHOWING CLOUD COVER THINNING OUT TO THE EAST OF THE COAST FROM VERO
BEACH NORTH. SKIES EAST OF THE COAST FROM FORT PIERCE SOUTH WERE
CLOUDY AND RADAR SHOWED HEAVIER RAIN ASSOCIATED WITH A LINE OF WIND
CONVERGENCE THAT STRETCHED PAST GRAND BAHAMA. ANOTHER AREA OF
HEAVIER RAIN WAS APPROACHING THE BREVARD VOLUSIA COUNTY COAST
BETWEEN CAPE CANAVERAL AND PONCE INLET. THIS AREA OF RAIN SHOULD BE
SHORT LIVED AS THE VERTICAL WIND PROFILER(S) AT THE SPACE CENTER
WERE DETECTING EASTERLY WINDS 15 TO 20 MPH PUSHING THE RAIN TOWARD
THE COAST.
MORNING UPDATE WILL LOOK AT POTENTIAL CHANGES TO SKY COVER. WINDS
LOOK GOOD BASED ON THE VERTICAL WIND PROFILER OBSERVATIONS.
PREVIOUS ZONES DISCUSSION
TODAY...HIGH PRESSURE CENTERED OVER NEW ENGLAND WILL SHIFT EAST
WHILE ITS RIDGE AXIS EXTENDS SOUTHWARD ALONG THE EASTERN SLOPES OF
THE APPALACHIANS. THIS SLIGHT SHIFT IN ORIENTATION OF THE HIGH
SHOULD ALLOW THE INVERTED COASTAL TROUGH JUST OFFSHORE THE FL
EAST COAST TO BREAK DOWN...CAUSING WINDS TO VEER FROM NORTH TO
NORTHEAST BUT REMAINING BREEZY. IT WILL ALSO BRING SHOWERS ACROSS
THE COAST AND HAVE INCREASED RAIN CHANCES TO 30 PERCENT ALONG THE
COAST...20 PERCENT INTERIOR...WHICH IS A LITTLE ABOVE MOS
GUIDANCE. WOULD NOT BE SURPRISED IF THE FOCUS FOR SHOWERS IS THIS
MORNING WITH SOME DECREASE IN RAIN CHANCES THIS AFTN. THUNDER IS
NOT EXPECTED. MAX TEMPS WILL REACH THE MID TO UPPER 70S WHICH IS A
FEW DEGREES ABOVE NORMAL.
TONIGHT...WIND FLOW IS FORECAST TO VEER A LITTLE MORE TO THE ENE.
AS A RESULT...THE GFS PULLS SOME HIGHER MOISTURE TOWARD THE COAST
ASSOCD WITH AN OLD FRONTAL BOUNDARY. SO WILL HOLD ONTO SLIGHT
CHANCE (20 PERCENT) POPS FOR THE COAST. SFC WINDS OVER THE
INTERIOR WILL BECOME LIGHT NORTH WHICH MAY PRODUCE SOME LOW
CLOUDS/PATCHY FOG OVER THE FAR INTERIOR.
SUN/MON...MID LEVEL FLOW WILL BRIEFLY BECOME ZONAL EARLY SUNDAY
BEFORE BACKING SUNDAY NIGHT AND EARLY MONDAY IN RESPONSE TO TAIL END
OF QUICK MOVING SHORTWAVE WHICH WILL PASS OFFSHORE BY SUNSET MONDAY.
SHALLOW/MOIST ONSHORE FLOW WILL ADVECT SMALL COVERAGE OF SHOWERS
ONSHORE SUNDAY THROUGH EARLY MONDAY...MAINLY IMPACTING COASTAL
COUNTIES. SURFACE CONVERGENCE ASSOCIATED WITH WEAK FRONT WILL
PROLONG ISOLATED SHOWERS CHANCE INTO MONDAY...EVEN INLAND. NW WIND
SHIFT BY LATE AFTERNOON/EVENING WILL RETURN DRIER AIRMASS. TEMPS
SEVERAL DEGREES ABOVE NORMAL...ESPECIALLY MINS NEAR THE COAST.
TUE-FRI...ZONAL MID LEVEL FLOW TUE BECOMES INCREASINGLY ANTICYCLONIC
MID-LATE WEEK WITH 500 MB HEIGHTS RISING 12+ DM AS A RIDGE BUILDS
FROM THE YUCATAN PENINSULA TO SOUTH FLORIDA TO NEAR BERMUDA.
MEANWHILE...SURFACE HIGH SINKS SLOWLY SE FROM NEAR THE CAROLINA
COAST TO THE WESTERN ATLANTIC WITH THE RIDGE AXIS DROPPING TO
NORTH FLORIDA BY LATE WEDNESDAY...THEN SETTLING TO THE
CENTRAL/SOUTH PENINSULA THU/FRI. GENERALLY LIGHT FLOW VEERS TO
EASTERLY WED/THU AND SE FRI...TAPPING 1000-500 MB RELATIVE
HUMIDITY VALUES IN THE 40-45 PERCENT RANGE. FORECAST WILL
THEREFORE REMAIN DRY DURING THE EXTENDED PERIOD...WITH THE NEXT
THREAT OF SHOWER LIKELY HOLDING OFF TIL NEXT FRONT POSSIBLY
APPROACHES NEXT WEEKEND. TEMPS FALL TO NEAR CLIMO TUE IN WAKE OF
FRONTAL BOUNDARY/WIND SHIFT...THEN WILL REBOUND NEAR TWO DEGREE
PER DAY WED-FRI AS ONSHORE/VEERING FLOW SLOWLY MODIFIES AIRMASS.
&&
.AVIATION...
IFR CEILINGS OVER THE INTERIOR WEST OF KMCO BECOME MVFR/VFR AFTER
15Z AS THE MODERATE TO FRESH EASTERLY FLOW COMING IN FROM THE EAST
PUSHES THE LOW CLOUDS OUT OF THE AREA. TEMPO MVFR CEILINGS AND
VISIBILITIES ALONG THE COAST AS SHOWERS COME OFF THE ATLANTIC AND
MOVE INLAND. LOOKING AT PREVAILING MVFR/VFR AFTER 15Z NORTH OF KFPR
AS VISIBLE SATELLITE IMAGES SHOW THE CLOUD COVER BECOMING SCATTERED.
PREVIOUS AVIATION DISCUSSION
OCCASIONAL CIGS NEAR 010 AGL WILL OCCUR AT MCO/SFB/DAB THROUGH 12Z
BUT THEN SHOULD DIMINISH AS WINDS VEER FROM NORTH TO NE. EXPECT
A HIGHER STRATOCUMULUS CEILING TO AFFECT MUCH OF THE COAST THROUGH
00Z WITH BASES MAINLY AT OR ABOVE 035 AGL. THERE IS A CHANCE FOR
TEMPO MVFR CONDS AS ISOLATED TO SCATTERED SHOWERS PUSH INTO THE
COAST. SOME OF THE STRATOCUMULUS WILL PUSH TO THE INTERIOR
TERMINALS.
&&
.MARINE...
CURRENT-THIS AFTERNOON...REPORTS FROM BUOY 009 20NM EAST OF CAPE
CANAVERAL HAS SHOWN STEADY EASTERLY WINDS IN THE 20 TO 25 KNOT RANGE
WITH A SHARP INCREASE FROM 7 FEET TO 8 AND 9 PLUS FEET THE PAST
COUPLE OF HOURS DUE TO THE STRONGER WINDS BUILDING THE SEAS. THE
SCRIPPS BUOY 4NM EAST OF PORT CANAVERAL WAS RECORDING 5 FOOT SEAS
AND THE BUOY 6NM NORTHEAST OF FORT PIERCE INLET WAS RECORDING 7 FOOT
SEAS. THE LATEST RUC AND MSAS SURFACE ANALYSIS INDICATE THAT THE
SURFACE TROUGH EAST OF FLORIDA WAS SLOW TO BREAK DOWN. WINDS/SEAS
MAY BE A BIT LOW BUT WILL WATCH THE BUOY REPORTS FOR ANOTHER HOUR
BEFORE MAKING ANY SIGNIFICANT CHANGES TO THE AFTERNOON FORECAST.
PREVIOUS MARINE DISCUSSION
TODAY/TONIGHT...BOATING CONDITIONS WILL REMAIN POOR FOR SMALL
CRAFT ESPECIALLY IN THE GULF STREAM. COASTAL TROUGH WILL BREAK
DOWN AND WINDS SHOULD BECOME UNIFORMLY NE ACROSS THE WATERS.
PRESSURE GRADIENT WILL SUPPORT 15-20 KNOTS WITH SEAS 5 TO 7
FEET...AND A LITTLE HIGHER IN THE GULF STREAM. SO WILL MAINTAIN
SMALL CRAFT ADVISORY FOR ALL THE WATERS TODAY. WINDS SHOULD
BEGIN TO DECREASE A BIT TONIGHT AS PRES GRAD SLACKENS SUPPORTING
AROUND 15 KNOTS. SHOULD BE ABLE TO TRANSITION TO ADVISORY FOR THE
GULF STREAM ONLY WITH A CAUTION FOR THE NEARSHORE WATERS TONIGHT.
SUN-WED...NE/E FLOW LESSENS BELOW 15 KT BUT LONG ONSHORE FETCH MEANS
SEAS WILL BE SLOW TO SUBSIDE. WILL EXTEND SCA FOR SEAS WITHIN THE
GULF STREAM THROUGH THE AFTERNOON. BRIEF INCREASE OF NW FLOW
BEHIND FRONT MONDAY WILL BUMP WINDS TO NEAR 15 KT AND SUSTAIN SEAS
5-6 FEET WITHIN GULF STREAM...AND 3-4 FT NEAR SHORE THROUGH
DAYBREAK TUE. WIND/SEA CONDITIONS IMPROVE SIGNIFICANTLY BY WED AS
LOW LEVEL RIDGE AXIS BUILDS DOWN THE ATLANTIC SEABOARD.
&&
.MLB WATCHES/WARNINGS/ADVISORIES...
FL...NONE.
AM...SMALL CRAFT ADVISORY UNTIL 4 PM EST THIS AFTERNOON FOR COASTAL
WATERS FROM FLAGLER BEACH TO SEBASTIAN INLET OUT 20 NM.
SMALL CRAFT ADVISORY UNTIL 4 PM EST SUNDAY FOR COASTAL WATERS
FROM SEBASTIAN INLET TO JUPITER INLET OUT 20 NM-WATERS FROM
FLAGLER BEACH TO JUPITER INLET 20 TO 60 NM OFFSHORE.
&&
$$
UPDATES.....WIMMER
IMPACT WX...PENDERGRAST
AREA FORECAST DISCUSSION
NWS INDIANAPOLIS IN
954 AM EST SAT NOV 30 2013
.UPDATE...
NEAR TERM FOR THE REST OF TODAY HAS BEEN UPDATED BELOW.
&&
.SYNOPSIS...
ISSUED AT 328 AM EST SAT NOV 30 2013
AFTER A MAINLY SUNNY DAY...CLOUDS WILL INCREASE ACROSS THE OHIO
VALLEY FOR THE SECOND HALF OF THE WEEKEND INTO EARLY NEXT WEEK AS A
WEAK FRONT SLIDES INTO THE REGION. A FEW LIGHT RAIN SHOWERS OR
SPRINKLES WILL BE POSSIBLE FROM SUNDAY AFTERNOON THROUGH MONDAY AS A
COUPLE OF WEAK WAVE ALOFT MOVE ACROSS THE OHIO VALLEY. A MUCH BETTER
CHANCE FOR RAIN WILL COME FOR THE SECOND HALF OF THE WEEK AS A
STRONG COLD FRONT TRACKS THROUGH THE REGION. COLDER AIR WILL ONCE
AGAIN RETURN BY THE END OF THE WEEK.
&&
.NEAR TERM /REST OF TODAY/...
ISSUED AT 954 AM EST SAT NOV 30 2013
UPDATE...
SOME MID/HIGH CLOUDS WERE STILL ACROSS OUR FAR EAST...BUT HAVE
CLEARED OUT ELSEWHERE. UPSTREAM SKIES WERE CLEAR AND WILL SCALE
BACK CLOUD COVER A LITTLE WITH MOST AREAS BEING SUNNY THIS
AFTERNOON.
ONLY OTHER CHANGE WAS TO TWEAK TEMPERATURES UP A DEGREE SOME AREAS
BASED ON 12Z RUC 2 METER TEMPERATURES...LOTS OF SUNSHINE AND WARM
ADVECTION. ALL IN ALL THE CURRENT FORECAST IS ON TRACK.
PREVIOUS NEAR TERM DISCUSSION FOLLOWS...
MID AND HIGH LEVEL CLOUD COVER DRAPED ACROSS MUCH OF THE OHIO VALLEY
EARLY THIS MORNING AS A WEAK WAVE ALOFT TRACKS ACROSS THE AREA.
TEMPS WERE MAINLY IN THE 20S AT 08Z.
BACK EDGE OF THE MORE SUBSTANTIAL HIGHER CLOUDS IS ALREADY EAST OF
THE MISSISSIPPI RIVER EARLY THIS MORNING. EXPECT CLOUDS TO DIMINISH
FROM WEST TO EAST ACROSS THE FORECAST AREA AROUND OR SHORTLY AFTER
DAYBREAK...WITH SKIES THEN BECOMING MOSTLY SUNNY WITH ONLY PATCHY
CIRRUS FOR THE REST OF THE DAY.
WITH THE BROAD HIGH PRESSURE RIDGE NOW LOCATED EAST OF THE
REGION...RETURN SOUTHERLY FLOW WILL DEVELOP AND INCREASE BY THIS
AFTERNOON AS BOUNDARY LAYER FLOW STRENGTHENS AHEAD OF AN APPROACHING
COLD FRONT. MODEL SOUNDINGS SUPPORT MAX GUSTS TO 20-25MPH BY THE
AFTERNOON AS LOW LEVEL MIXING INCREASES. GUSTS WILL DROP OFF NEAR
SUNSET AS THE NOCTURNAL INVERSION ESTABLISHES.
TEMPS...SOUTHERLY FLOW AND WARM ADVECTION WILL BRING WARMER TEMPS
INTO CENTRAL INDIANA FOR TODAY. MOS GUIDANCE MATCHES UP NICELY WITH
LOW LEVEL THERMALS...WITH HIGHS TOPPING OUT NEAR LATE NOVEMBER
NORMALS IN THE MID/UPPER 40S.
&&
.SHORT TERM /TONIGHT THROUGH MONDAY NIGHT/...
ISSUED AT 328 AM EST SAT NOV 30 2013
FORECAST CHALLENGES FOCUS ON POTENTIAL FOR LIGHT PRECIP AS THE
AFOREMENTIONED COLD FRONT DROPS INTO THE REGION...STALLS AND
EVENTUALLY WASHES OUT.
PREDOMINANT ZONAL FLOW IN THE UPPER LEVELS WILL BE PRESENT THROUGH
THE PERIOD WITH SEVERAL WEAK WAVES ALOFT TRACKING QUICKLY THROUGH
THE OHIO VALLEY. AT THE SURFACE...THE COLD FRONT WILL SLIDE SLOWLY
SOUTH INTO THE REGION ON SUNDAY...EVENTUALLY STALLING OUT OVER
SOUTHERN INDIANA SUNDAY NIGHT BEFORE WASHING OUT MONDAY. MOISTURE
ACCOMPANYING THE FRONT WILL BE LIMITED...BUT MODEL SOUNDINGS AND RH
PROGS CONTINUE TO SHOW IT IN GREATEST ABUNDANCE IN THE UPPER
PORTIONS OF THE BOUNDARY LAYER BEGINNING EARLY SUNDAY...GRADUALLY
LOWERING TO AROUND 2-3KFT INTO MONDAY AS AN INVERSION STEADILY
STRENGTHENS.
EXPECT CLOUDS TO EXPAND SOUTHEAST INTO THE FORECAST AREA AHEAD OF
THE FRONT BEGINNING LATE TONIGHT AND CONTINUING INTO SUNDAY. WEAK
ISENTROPIC LIFT AND A SUBTLE WAVE ALOFT MAY BE JUST ENOUGH TO
GENERATE SOME LIGHT PRECIP SUNDAY AFTERNOON AND NIGHT...LIKELY IN
THE FORM OF SPRINKLES...DRIZZLE OR VERY LIGHT RAIN SHOWERS. LOW
LEVELS AND SURFACE TEMPS SHOULD REMAIN WARM ENOUGH TO SUPPORT PRECIP
TYPE AS RAIN ONLY SUNDAY NIGHT. MODEL GUIDANCE LARGELY IN AGREEMENT
ON BRINGING A SLIGHTLY STRONGER...BETTER PHASED UPPER WAVE ACROSS
THE OHIO VALLEY ON MONDAY. WITH LOW LEVEL MOISTURE IN ABUNDANCE...
THIS FEATURE SHOULD PRESENT A BETTER OPPORTUNITY FOR A FEW LIGHT
RAIN SHOWERS. WILL CARRY JUST LOW CHANCE POPS HOWEVER AS ISENTROPIC
LIFT REMAINS WEAK. MAJORITY OF THE MODEL GUIDANCE FAVORING THE
PASSAGE OF THIS UPPER WAVE BY MONDAY EVENING...AND WILL END PRECIP
CHANCES AS RIDGING ALOFT EXPANDS INTO THE OHIO VALLEY BY EARLY
TUESDAY.
TEMPS...CONSIDERING THE INCREASING CLOUDS AND POTENTIAL FOR WEAK
COLD ADVECTION TO DEVELOP ON SUNDAY...METMOS TEMPS IN THE UPPER
40S/LOWER 50S LOOK RATHER AGGRESSIVE. HAVE TRENDED CLOSER TO /BUT
NOT AS COLD AS/ THE MAVMOS FOR SUNDAY HIGHS. LEANED TOWARDS THE
MAVMOS AGAIN FOR MONDAY WITH LIGHT RAIN/CLOUDS PRESENT. NEAR MAVMOS
FOR LOWS TONIGHT...THEN TRENDED TOWARDS THE WARMER METMOS FOR SUNDAY
NIGHT WITH EXPECTED CLOUD COVER.
&&
.LONG TERM /TUESDAY THROUGH FRIDAY/...
ISSUED AT 328 AM EST SAT NOV 30 2013
ENSEMBLES ARE IN GOOD AGREEMENT ON THE EVOLVING WEATHER PATTERN NEXT
WEEK. UPPER RIDGING EXPECTED TO DEVELOP ALONG THE EAST COAST AS A
TROUGH SETS UP FROM THE NORTHERN MIDWEST BACK INTO THE SOUTHERN
ROCKIES. THIS WILL RESULT IN SOUTHWESTERLY UPPER FLOW LOCALLY.
APPEARS A DECENT CHUNK OF ENERGY WILL EJECT OUT OF THE WESTERN
TROUGH INTO WESTERN GREAT LAKES AROUND NEXT THURSDAY. WILL KEEP POPS
IN THE FORECAST FOR RAIN ON WEDNESDAY AND ESPECIALLY THURSDAY AS THE
UPPER DISTURBANCE MOVES THROUGH.
SEVERAL ENSEMBLES SUGGEST MORE ENERGY MAY EJECT OUT ACROSS THE OHIO
OR TENNESSEE VALLEY AROUND NEXT FRIDAY...WHICH MAY INDUCE A SURFACE
WAVE ON THE PRIMARY COLD FRONT. WILL GO WITH CHANCE POPS FOR RAIN OR
SNOW AT THAT TIME. AT THIS POINT...THE ENSEMBLES INDICATE ANY SNOW
ACCUMULATIONS LATE NEXT WEEK WILL BE MINOR.
&&
.AVIATION /DISCUSSION FOR THE 301500Z TAF UPDATE/...
ISSUED AT 920 AM EST SAT NOV 30 2013
KIND TAF LOOKS GOOD. ONLY MINOR TWEAKS MADE.
PREVIOUS DISCUSSION FOLLOWS...
NO SIGNIFICANT CLOUD COVER...UNRESTRICTED VISIBILITY...SURFACE WINDS
AT OR BELOW 10 KTS EXPECTED AT THE TAF SITES THROUGH 010000Z.
&&
.IND WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
SYNOPSIS...RYAN
NEAR TERM...RYAN/JH
SHORT TERM...RYAN
LONG TERM....JAS
AVIATION...JAS/50
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AREA FORECAST DISCUSSION
NWS RALEIGH NC
1051 AM EST SAT NOV 30 2013
.SYNOPSIS...
HIGH PRESSURE WILL EXTEND SOUTHWEST INTO THE REGION THROUGH
TONIGHT...THEN WEAKEN ON SUNDAY. A LOW PRESSURE SYSTEM IS EXPECTED
TO DEVELOP ALONG THE CAROLINA COAST ON MONDAY AS AN UPPER LEVEL
DISTURBANCE APPROACHES FROM THE WEST.
&&
.NEAR TERM /THROUGH TODAY/...
AS OF 1050 AM SATURDAY...
SURFACE HIGH AS OF 15Z IS CENTERED WELL TO THE NORTHEAST...OVER NEW
ENGLAND AND INTO MAINE...WITH THE RIDGE AXIS EXTENDING SOUTHWEST INTO
NC...MAINLY ALONG THE WESTERN PORTION OF THE AREA. THE PRESSURE
GRADIENT WILL RELAX SOME AS THE HIGH MOVES OFF THE NE COAST AND THE
RIDGE WEAKENS...THUS ALLOWING THE WINDS TO RELAX SOME AS WELL. THE
RETURN FLOW WILL BECOME MORE NORTHEASTERLY AS THAT HAPPENS...
ALLOWING FOR WARMER TEMPS ACROSS THE SOUTH AND EAST AND COOLER IN
THE NW. THE 12Z UPPER AIR ANALYSES SHOW THE TROUGH... MORE PROMINENT
AT 700 AND 850 MB...EXTENDING FROM THE WESTERN GREAT LAKES SW INTO
OK/TX...WITH HIGH PRESSURE/RIDGING OVER THE EASTERN US. AN UPPER
LEVEL WAVE JUST WEST OF THE APPALACHIANS...SHOWN IN BOTH SATELLITE
IMAGERY AND INDICATED BY MODEL GENERATED VORTICITY PLOTS...IS
GENERATING AN AREA OF CLOUDS OVER WV/VA...WHICH MAY EXTEND INTO THE
NORTHERN AND WESTERN PORTIONS OF THE AREA TODAY...ALTHOUGH THE
GREATEST COVERAGE WILL BE OVER VA. WITH THE STRONG WESTERLY FLOW
ALOFT EXPECTED TO CONTINUE TODAY AS THE UPPER LEVEL RIDGE CONTINUES
TO BUILD...SUBSIDENCE SHOULD BE STRONG ENOUGH TO LIMIT MIXING IN THE
LOW LEVELS...WHICH IN COMBINATION WITH THE INCREASING CLOUD COVER...
SHOULD BE ENOUGH TO YIELD HIGHS TODAY A BIT COOLER THAN YESTERDAY...
MAINLY IN THE MID 40S TO LOW 50S. -KC
THE LATEST RAP...ALONG WITH THE HRRR WRF...FORECAST AN INCREASE IN
LOW-LEVEL MOISTURE FROM THE SOUTHEAST LATE IN THE DAY. THIS MAY BE
REASONABLE...AS THE SATELLITE FOG PRODUCT SHOWED AREAS OF LOW CLOUDS
JUST OFFSHORE FROM SOUTHEAST NORTH CAROLINA EARLY THIS MORNING. HAVE
ADDED SOME CLOUD COVER TO THE FORECAST PARTICULARLY TOWARD THE SOUTH
AND EAST DURING THE AFTERNOON. -DJF
&&
.SHORT TERM /TONIGHT THROUGH SUNDAY NIGHT/...
AS OF 650 AM SATURDAY...
SURFACE HIGH PRESSURE SHOULD BE DIRECTLY OVERHEAD OVERNIGHT KEEPING
THE GRADIENT VERY RELAXED. THE POTENTIAL FOR A QUITE CHILLY NIGHT
WOULD EXIST BUT THE COMBINATION OF SOME HIGH CLOUDS AND THE GFS
FORECAST OF INCREASING 850MB MOISTURE FROM THE SOUTH AND SOUTHWEST
MAY ACT TO KEEP TEMPERATURES CLOSE TO THE GUIDANCE LOWS OVERNIGHT.
THE LATEST SATELLITE FOG PRODUCT SHOWS LOW-LEVEL MOISTURE MOVING
WEST TOWARD THE SOUTH CAROLINA COAST...AND LOW-LEVEL ISENTROPIC
FORECASTS ALONG WITH THE INCREASING 850MB MOISTURE SUPPORT AN
INCREASE IN CLOUD COVER TO PARTLY-TO-MOSTLY CLOUDY PARTICULARLY
ALONG AND SOUTH OF ABOUT INTERSTATE 85 DURING THE OVERNIGHT HOURS.
THE TIMING OF THIS IS...OF COURSE...CRITICAL TO THE OVERNIGHT
TEMPERATURE FORECAST...BUT FOR THIS FORECAST WILL LEAN TOWARD THE
COOLER MOS GUIDANCE IN THE TRIAD AND THE WARMER MOS GUIDANCE
ELSEWHERE.
K INDICES SLOWLY RISE SUNDAY...WITH PRECIPITABLE WATER VALUES RISING
LATE SUNDAY TO BETWEEN 0.75 AND ONE INCH...ABOVE NORMAL FOR VERY
EARLY DECEMBER AT ABOUT THE 75TH PERCENTILE. LIFT STARTS TO INCREASE
LATE SUNDAY AND PARTICULARLY SUNDAY NIGHT AS ISENTROPIC LIFT ON THE
300K SURFACE INCREASES...WITH THE BEST POTENTIAL VORTICITY ON THE
1.5PVU SURFACE FORECAST BY THE GFS ALONG AND SOUTH OF ABOUT U.S. 64
LATE SUNDAY THROUGH SUNDAY NIGHT. SURFACE DEPICTIONS OF THE NAM AND
GFS DIFFER AND ARE FAIRLY CONSISTENT WITH THEMSELVES OVER THE LAST
TWO OR THREE RUNS...WITH THE NAM SHOWING A WEAK SURFACE LOW JUST OFF
THE SOUTH CAROLINA COAST SUNDAY NIGHT WHILE THE GFS FORECASTS MORE
OF AN INVERTED TROUGH BEFORE SURFACE LOW PRESSURE STRENGTHENS
OFFSHORE. REGARDLESS...QPF AND MOS GUIDANCE POPS ARE SIMILAR...
KEEPING MOST CHANCES FOR PRECIPITATION AT BAY SUNDAY AND INCREASING
CHANCES OVER MOST OF CENTRAL NORTH CAROLINA SUNDAY NIGHT. WILL NOTE
A SLIGHT CHANCE OF RAIN MAINLY OVER THE SANDHILLS AND SOUTHERN
COASTAL PLAIN SUNDAY WHERE THE BEST LOW-LEVEL MOISTURE SHOULD RESIDE
AS POTENTIAL VORTICITY INCREASES...WITH A CHANCE OF RAIN SUNDAY
NIGHT MAINLY ALONG AND EAST OF A LINE FROM ABOUT KIXA TO KAFP WITH A
SLIGHT CHANCE NORTH OF THAT LINE. DEBATED WHETHER OR NOT TO INCLUDE
A SLIGHT CHANCE IN THE TRIAD AND FOR THIS FORECAST WILL SHOW A VERY
LOW SLIGHT CHANCE THERE OVERNIGHT SUNDAY...THOUGH THIS COULD END UP
BEING OVERDONE WITH SUFFICIENT MOISTURE AND LIFT REMAINING JUST
EAST. SURFACE WET BULB TEMPERATURES AND PARTIAL THICKNESSES SUPPORT
ALL LIQUID.
ONCE AGAIN 1000-850MB THICKNESSES WOULD SUPPORT HIGHS SUNDAY ABOVE
MOS GUIDANCE...BUT GIVEN THE EXPECTED CLOUD COVER...WILL FORECAST
HIGHS AS A BLEND OF MAV AND MET MOS GUIDANCE FOR A FAIRLY UNIFORM
LOWER 50S IN MOST LOCATIONS. OVERNIGHT SUNDAY...IF IT REMAINS DRY IN
THE TRIAD LOWS SHOULD BE NEAR THE WARMER GUIDANCE...WHILE WHERE IT
RAINS TEMPERATURES WOULD APPROACH THE DEW POINT. THIS COINCIDES WITH
A BLEND OF MOS GUIDANCE...ALTHOUGH HIGHER THAN GUIDANCE TOWARD
KRWI...FOR LOWS IN THE MID TO UPPER 30S NORTHWEST...TO MID 40S
TOWARD KCTZ.
&&
.LONG TERM /MONDAY THROUGH FRIDAY/...
AS OF 235 AM SATURDAY...
ON MONDAY A LOW AMPLITUDE NORTHERN STREAM SHORTWAVE DROPS INTO THE
THE DEEP SOUTH AS A SHEARING SOUTHERN STREAM SYSTEM WITH A 250MB JET
OF 140 KTS PHASE TOGETHER BEFORE THE TROUGH AXIS MOVES OFF THE
SOUTHEAST COAST MONDAY NIGHT. THE TROUGH BECOMES NEGATIVELY TILTED
AND INITIATES SURFACE CYCLOGENESIS MONDAY NIGHT AND TUESDAY. RECENT
NWP TRENDS HAVE SUGGESTED A LESS AMPLIFIED SYSTEM WHILE PRODUCING A
BIT MORE QPF ACROSS MAINLY SOUTHEASTERN NC. IT REMAINS DIFFICULT AND
CONFIDENCE IS LOW REGARDING HOW FAR NORTH AND WEST PRECIPITATION
WILL SPREAD ACROSS CENTRAL NC BUT CONFIDENCE IS GROWING THAT SOME
LIGHT PRECIPITATION WILL FALL ACROSS THE SOUTHERN COASTAL PLAIN AND
SANDHILLS REGION. NWP CONSENSUS SHOWS THE DEEPEST MOISTURE AND
STRONGEST FORCING WILL BE CONFINED TO SOUTHEASTERN PORTIONS OF THE
RAH CWA WITH RAPIDLY DECREASING RAIN CHANCES ACROSS THE NORTHERN AND
WESTERN PIEDMONT. ISENTROPIC ANALYSIS DEPICTS THE PATTERN WELL WITH
A FAIRLY NARROW CORRIDOR OF LIFT/SATURATION THAT SLIDES MAINLY
ACROSS SOUTHERN AND EASTERN NC. PRECIPITATION CHANCES QUICKLY TAIL
OFF FROM WEST TO EAST ON MONDAY NIGHT. THE AIR MASS AHEAD OF THE
SYSTEM WILL HAVE MODIFIED AND THE PRECIPITATION WILL FALL AS RAIN.
GIVEN THE MODIFICATION OF THE AIR MASS AND THE LIGHT PRECIPITATION
CHANCES...DO NOT EXPECT A SIGNIFICANT CAD EVENT TO OCCUR. HIGHS
MONDAY WILL RANGE IN THE 49-56 RANGE WITH MAX TEMPERATURES DEPENDENT
ON THE LOCATION AND INTENSITY OF THE PRECIPITATION.
AFTER THE UPPER TROUGH AXIS MOVES OFFSHORE...THE FLOW ALOFT BECOMES
MORE NORTHWESTERLY. ANOTHER DISTURBANCE IN THE FLOW AND SOME
RESIDUAL MOISTURE SHOULD BE SUFFICIENT TO PRODUCE SOME CLOUDINESS ON
TUESDAY BUT OTHERWISE FAIR CONDITIONS ARE EXPECTED WITH HIGHS IN THE
LOWER TO MID 50S.
THE FLOW FLATTENS ON TUESDAY NIGHT AND HEIGHTS RISE ON WEDNESDAY
INTO THURSDAY WITH INCREASING HIGH CLOUDS LATE WEDNESDAY AND A FAIR
AMOUNT OF CLOUDS EXPECTED ON THURSDAY. EXPECT DRY WEATHER THROUGH AT
LEAST THURSDAY AFTERNOON AS THE RIDGE AXIS BUILDS OVERHEAD.
MODERATING TEMPERATURES ARE EXPECTED ON THURSDAY INTO FRIDAY WITH
HIGHS IN THE MID TO UPPER 50S ON WEDNESDAY WARMING INTO THE UPPER
50S TO LOWER 60S ON THURSDAY WITH MORNING LOWS IN THE MID 30S TO
AROUND 40.
A LONGWAVE TROUGH DEVELOPS OVER THE WESTERN U.S. LATE THURSDAY INTO
FRIDAY AS AN ARCTIC AIRMASS DROPS INTO THE NORTHERN ROCKIES AND
NORTHERN PLAINS. AN INCREASINGLY MOIST SOUTHERLY TO SOUTHWESTERLY
FLOW DEVELOPS ACROSS THE CENTRAL U.S. AS THE TROUGH PUSHES EAST ON
FRIDAY. THE ASSOCIATED COLD FRONT REACHES THE WESTERN APPALACHIANS
ON FRIDAY MORNING. THERE ARE TIMING DIFFERENCES AMONG THE GUIDANCE
REGARDING THE EASTWARD ADVANCEMENT OF THE FRONT AND THE ASSOCIATED
PRECIPITATION WITH WPC PREFERRING A GEFS MEAN AND EC ENS MEAN.
REGARDLESS...THE THREAT OF RAIN WILL ARRIVE WITH LOW PROBABILITIES
IN THE WEST LATE THURSDAY NIGHT. POPS WILL INCREASE FROM WEST TO
EAST FRIDAY AND FRIDAY NIGHT WITH THE BEST CHANCE OF RAIN AT THIS
POINT APPEARING TO BE FRIDAY NIGHT AND SATURDAY. AHEAD OF THE FRONT
AND THE RAIN...TEMPERATURES ARE LIKELY TO CLIMB INTO THE 60S FRIDAY
AFTERNOON. -BLAES
&&
.AVIATION /12Z SATURDAY THROUGH WEDNESDAY/...
AS OF 650 AM SATURDAY...
VFR CONDITIONS CONTINUE THROUGH MUCH OF THE 12Z VALID TAF PERIOD.
WINDS REMAIN NOTICEABLE DURING THE EARLY MORNING IN THE TIGHTER
GRADIENT ON THE EAST SIDE OF THE RIDGE AXIS...AND THE KRAX WSR-88D
SHOWED WINDS OF 40KT EARLIER JUST ABOVE 2K FEET...BUT THESE WINDS
HAVE SINCE DIMINISHED ALMOST IN HALF SINCE 06Z. MODEL GUIDANCE SHOWS
SUCH WINDS CONTINUING TO DECREASE SOME DURING THE MORNING...BUT
THESE COULD TRANSLATE TO A FEW WIND GUSTS IN THE TEENS KTS AFTER
SUNRISE WITH EVEN MINIMAL MIXING AT KRDU AND ESPECIALLY KFAY AND
KRWI. AS HIGH PRESSURE SETTLES OVERHEAD FOR THIS EVENING...WINDS
SHOULD BECOME LIGHT. AS LOW-LEVEL MOISTURE INCREASES THIS EVENING
AND OVERNIGHT...THERE IS THE POTENTIAL FOR AT LEAST A PERIOD OF MVFR
CEILINGS PARTICULARLY TOWARD KFAY WITH A LESSER LIKELIHOOD TOWARD
KRDU AND KRWI.
BEYOND THE 12Z VALID TAF PERIOD...SUB-VFR CONDITIONS ARE POSSIBLE
EARLY SUNDAY MAINLY TOWARD KFAY...AND SUCH CONDITIONS ARE QUITE
POSSIBLE SUNDAY NIGHT MAINLY EAST AND SOUTHEAST OF THE TRIAD AS
MOISTURE INCREASES...ALONG WITH A CHANCE OF RAIN MAINLY EAST AND
SOUTHEAST OF THE TRIAD. THE PROBABILITY OF SUB-VFR CONDITIONS
INCREASES LATE SUNDAY NIGHT INTO MONDAY...AGAIN BEST EAST AND
SOUTHEAST OF THE TRIAD...WITH IMPROVING CONDITIONS FOR TUESDAY
CONTINUING INTO WEDNESDAY.
&&
.RAH WATCHES/WARNINGS/ADVISORIES...
NONE
&&
$$
SYNOPSIS...VINCENT
NEAR TERM...KC/DJF
SHORT TERM...DJF
LONG TERM...BLAES
AVIATION...DJF
AREA FORECAST DISCUSSION
NWS RALEIGH NC
958 AM EST SAT NOV 30 2013
.SYNOPSIS...
HIGH PRESSURE WILL EXTEND SOUTHWEST INTO THE REGION THROUGH
TONIGHT...THEN WEAKEN ON SUNDAY. A LOW PRESSURE SYSTEM IS EXPECTED
TO DEVELOP ALONG THE CAROLINA COAST ON MONDAY AS AN UPPER LEVEL
DISTURBANCE APPROACHES FROM THE WEST.
&&
.NEAR TERM /THROUGH TODAY/...
AS OF 650 AM SATURDAY...
THE LATEST SURFACE ANALYSIS SHOWED THE AXIS OF SURFACE HIGH PRESSURE
NORTHEAST TO SOUTHWEST ACROSS CENTRAL NORTH CAROLINA...AND DURING
THE DAY THE RIDGE SETTLES SLOWLY SOUTH WHICH SHOULD RELAX THE
GRADIENT FOR THE LATE DAY AND OVERNIGHT. A MODERATE MID-LEVEL
SHORTWAVE WAS OBSERVED ON WATER VAPOR IMAGERY MOVING EAST FROM
MISSOURI AND ILLINOIS TOWARD THE MID-ATLANTIC...WITH A MID-LEVEL
TROUGH PASSING EAST OF THE STATE AS OF THIS WRITING. 1000-850MB
THICKNESSES ARE FORECAST VERY SIMILAR TO THOSE THAT OCCURRED
FRIDAY...WHEN HIGHS WERE AROUND 50 TO THE MID 50S. HOWEVER...
GUIDANCE IS VERY CONSISTENT IN SHOWING HIGHS TODAY ROUGHLY A
CATEGORY...POSSIBLY EVEN TWO...COOLER. NAM AND GFS BUFR SOUNDINGS
MAINTAIN STRONG SUBSIDENCE AND LIMITED MIXING POTENTIAL...AND AHEAD
OF THE MODEST MID-LEVEL SHORTWAVE TO OUR WEST THAT BOTH THE NAM AND
THE GFS MOVE ACROSS CENTRAL NORTH CAROLINA LATE THIS AFTERNOON AND
OVERNIGHT...DIFFLUENCE ALOFT INCREASES AS A 90KT 300MB JET
APPROACHES FROM THE WEST...WITH POSSIBLY JUST ENOUGH HIGH CLOUDS TO
TEMPER HIGHS SOMEWHAT. WILL LEAN TOWARD WARMER GUIDANCE FOR HIGHS IN
THE MID 40S TO LOWER 50S. ESPECIALLY ALONG AND EAST OF U.S. 1 THERE
SHOULD BE JUST A FEW WIND GUSTS IN THE TEENS KNOTS WITH MIXING LATER
THIS MORNING BEFORE THE SURFACE RIDGING SETTLES SOUTH. 925MB WINDS
ARE FORECAST ONLY TO AROUND 15KT DURING THE DAY.
THE LATEST RAP...ALONG WITH THE HRRR WRF...FORECAST AN INCREASE IN
LOW-LEVEL MOISTURE FROM THE SOUTHEAST LATE IN THE DAY. THIS MAY BE
REASONABLE...AS THE SATELLITE FOG PRODUCT SHOWED AREAS OF LOW CLOUDS
JUST OFFSHORE FROM SOUTHEAST NORTH CAROLINA EARLY THIS MORNING. HAVE
ADDED SOME CLOUD COVER TO THE GRIDDED AND WORDED FORECASTS
PARTICULARLY TOWARD KCTZ DURING THE AFTERNOON.
&&
.SHORT TERM /TONIGHT THROUGH SUNDAY NIGHT/...
AS OF 650 AM SATURDAY...
SURFACE HIGH PRESSURE SHOULD BE DIRECTLY OVERHEAD OVERNIGHT KEEPING
THE GRADIENT VERY RELAXED. THE POTENTIAL FOR A QUITE CHILLY NIGHT
WOULD EXIST BUT THE COMBINATION OF SOME HIGH CLOUDS AND THE GFS
FORECAST OF INCREASING 850MB MOISTURE FROM THE SOUTH AND SOUTHWEST
MAY ACT TO KEEP TEMPERATURES CLOSE TO THE GUIDANCE LOWS OVERNIGHT.
THE LATEST SATELLITE FOG PRODUCT SHOWS LOW-LEVEL MOISTURE MOVING
WEST TOWARD THE SOUTH CAROLINA COAST...AND LOW-LEVEL ISENTROPIC
FORECASTS ALONG WITH THE INCREASING 850MB MOISTURE SUPPORT AN
INCREASE IN CLOUD COVER TO PARTLY-TO-MOSTLY CLOUDY PARTICULARLY
ALONG AND SOUTH OF ABOUT INTERSTATE 85 DURING THE OVERNIGHT HOURS.
THE TIMING OF THIS IS...OF COURSE...CRITICAL TO THE OVERNIGHT
TEMPERATURE FORECAST...BUT FOR THIS FORECAST WILL LEAN TOWARD THE
COOLER MOS GUIDANCE IN THE TRIAD AND THE WARMER MOS GUIDANCE
ELSEWHERE.
K INDICES SLOWLY RISE SUNDAY...WITH PRECIPITABLE WATER VALUES RISING
LATE SUNDAY TO BETWEEN 0.75 AND ONE INCH...ABOVE NORMAL FOR VERY
EARLY DECEMBER AT ABOUT THE 75TH PERCENTILE. LIFT STARTS TO INCREASE
LATE SUNDAY AND PARTICULARLY SUNDAY NIGHT AS ISENTROPIC LIFT ON THE
300K SURFACE INCREASES...WITH THE BEST POTENTIAL VORTICITY ON THE
1.5PVU SURFACE FORECAST BY THE GFS ALONG AND SOUTH OF ABOUT U.S. 64
LATE SUNDAY THROUGH SUNDAY NIGHT. SURFACE DEPICTIONS OF THE NAM AND
GFS DIFFER AND ARE FAIRLY CONSISTENT WITH THEMSELVES OVER THE LAST
TWO OR THREE RUNS...WITH THE NAM SHOWING A WEAK SURFACE LOW JUST OFF
THE SOUTH CAROLINA COAST SUNDAY NIGHT WHILE THE GFS FORECASTS MORE
OF AN INVERTED TROUGH BEFORE SURFACE LOW PRESSURE STRENGTHENS
OFFSHORE. REGARDLESS...QPF AND MOS GUIDANCE POPS ARE SIMILAR...
KEEPING MOST CHANCES FOR PRECIPITATION AT BAY SUNDAY AND INCREASING
CHANCES OVER MOST OF CENTRAL NORTH CAROLINA SUNDAY NIGHT. WILL NOTE
A SLIGHT CHANCE OF RAIN MAINLY OVER THE SANDHILLS AND SOUTHERN
COASTAL PLAIN SUNDAY WHERE THE BEST LOW-LEVEL MOISTURE SHOULD RESIDE
AS POTENTIAL VORTICITY INCREASES...WITH A CHANCE OF RAIN SUNDAY
NIGHT MAINLY ALONG AND EAST OF A LINE FROM ABOUT KIXA TO KAFP WITH A
SLIGHT CHANCE NORTH OF THAT LINE. DEBATED WHETHER OR NOT TO INCLUDE
A SLIGHT CHANCE IN THE TRIAD AND FOR THIS FORECAST WILL SHOW A VERY
LOW SLIGHT CHANCE THERE OVERNIGHT SUNDAY...THOUGH THIS COULD END UP
BEING OVERDONE WITH SUFFICIENT MOISTURE AND LIFT REMAINING JUST
EAST. SURFACE WET BULB TEMPERATURES AND PARTIAL THICKNESSES SUPPORT
ALL LIQUID.
ONCE AGAIN 1000-850MB THICKNESSES WOULD SUPPORT HIGHS SUNDAY ABOVE
MOS GUIDANCE...BUT GIVEN THE EXPECTED CLOUD COVER...WILL FORECAST
HIGHS AS A BLEND OF MAV AND MET MOS GUIDANCE FOR A FAIRLY UNIFORM
LOWER 50S IN MOST LOCATIONS. OVERNIGHT SUNDAY...IF IT REMAINS DRY IN
THE TRIAD LOWS SHOULD BE NEAR THE WARMER GUIDANCE...WHILE WHERE IT
RAINS TEMPERATURES WOULD APPROACH THE DEW POINT. THIS COINCIDES WITH
A BLEND OF MOS GUIDANCE...ALTHOUGH HIGHER THAN GUIDANCE TOWARD
KRWI...FOR LOWS IN THE MID TO UPPER 30S NORTHWEST...TO MID 40S
TOWARD KCTZ.
&&
.LONG TERM /MONDAY THROUGH FRIDAY/...
AS OF 235 AM SATURDAY...
ON MONDAY A LOW AMPLITUDE NORTHERN STREAM SHORTWAVE DROPS INTO THE
THE DEEP SOUTH AS A SHEARING SOUTHERN STREAM SYSTEM WITH A 250MB JET
OF 140 KTS PHASE TOGETHER BEFORE THE TROUGH AXIS MOVES OFF THE
SOUTHEAST COAST MONDAY NIGHT. THE TROUGH BECOMES NEGATIVELY TILTED
AND INITIATES SURFACE CYCLOGENESIS MONDAY NIGHT AND TUESDAY. RECENT
NWP TRENDS HAVE SUGGESTED A LESS AMPLIFIED SYSTEM WHILE PRODUCING A
BIT MORE QPF ACROSS MAINLY SOUTHEASTERN NC. IT REMAINS DIFFICULT AND
CONFIDENCE IS LOW REGARDING HOW FAR NORTH AND WEST PRECIPITATION
WILL SPREAD ACROSS CENTRAL NC BUT CONFIDENCE IS GROWING THAT SOME
LIGHT PRECIPITATION WILL FALL ACROSS THE SOUTHERN COASTAL PLAIN AND
SANDHILLS REGION. NWP CONSENSUS SHOWS THE DEEPEST MOISTURE AND
STRONGEST FORCING WILL BE CONFINED TO SOUTHEASTERN PORTIONS OF THE
RAH CWA WITH RAPIDLY DECREASING RAIN CHANCES ACROSS THE NORTHERN AND
WESTERN PIEDMONT. ISENTROPIC ANALYSIS DEPICTS THE PATTERN WELL WITH
A FAIRLY NARROW CORRIDOR OF LIFT/SATURATION THAT SLIDES MAINLY
ACROSS SOUTHERN AND EASTERN NC. PRECIPITATION CHANCES QUICKLY TAIL
OFF FROM WEST TO EAST ON MONDAY NIGHT. THE AIR MASS AHEAD OF THE
SYSTEM WILL HAVE MODIFIED AND THE PRECIPITATION WILL FALL AS RAIN.
GIVEN THE MODIFICATION OF THE AIR MASS AND THE LIGHT PRECIPITATION
CHANCES...DO NOT EXPECT A SIGNIFICANT CAD EVENT TO OCCUR. HIGHS
MONDAY WILL RANGE IN THE 49-56 RANGE WITH MAX TEMPERATURES DEPENDENT
ON THE LOCATION AND INTENSITY OF THE PRECIPITATION.
AFTER THE UPPER TROUGH AXIS MOVES OFFSHORE...THE FLOW ALOFT BECOMES
MORE NORTHWESTERLY. ANOTHER DISTURBANCE IN THE FLOW AND SOME
RESIDUAL MOISTURE SHOULD BE SUFFICIENT TO PRODUCE SOME CLOUDINESS ON
TUESDAY BUT OTHERWISE FAIR CONDITIONS ARE EXPECTED WITH HIGHS IN THE
LOWER TO MID 50S.
THE FLOW FLATTENS ON TUESDAY NIGHT AND HEIGHTS RISE ON WEDNESDAY
INTO THURSDAY WITH INCREASING HIGH CLOUDS LATE WEDNESDAY AND A FAIR
AMOUNT OF CLOUDS EXPECTED ON THURSDAY. EXPECT DRY WEATHER THROUGH AT
LEAST THURSDAY AFTERNOON AS THE RIDGE AXIS BUILDS OVERHEAD.
MODERATING TEMPERATURES ARE EXPECTED ON THURSDAY INTO FRIDAY WITH
HIGHS IN THE MID TO UPPER 50S ON WEDNESDAY WARMING INTO THE UPPER
50S TO LOWER 60S ON THURSDAY WITH MORNING LOWS IN THE MID 30S TO
AROUND 40.
A LONGWAVE TROUGH DEVELOPS OVER THE WESTERN U.S. LATE THURSDAY INTO
FRIDAY AS AN ARCTIC AIRMASS DROPS INTO THE NORTHERN ROCKIES AND
NORTHERN PLAINS. AN INCREASINGLY MOIST SOUTHERLY TO SOUTHWESTERLY
FLOW DEVELOPS ACROSS THE CENTRAL U.S. AS THE TROUGH PUSHES EAST ON
FRIDAY. THE ASSOCIATED COLD FRONT REACHES THE WESTERN APPALACHIANS
ON FRIDAY MORNING. THERE ARE TIMING DIFFERENCES AMONG THE GUIDANCE
REGARDING THE EASTWARD ADVANCEMENT OF THE FRONT AND THE ASSOCIATED
PRECIPITATION WITH WPC PREFERRING A GEFS MEAN AND EC ENS MEAN.
REGARDLESS...THE THREAT OF RAIN WILL ARRIVE WITH LOW PROBABILITIES
IN THE WEST LATE THURSDAY NIGHT. POPS WILL INCREASE FROM WEST TO
EAST FRIDAY AND FRIDAY NIGHT WITH THE BEST CHANCE OF RAIN AT THIS
POINT APPEARING TO BE FRIDAY NIGHT AND SATURDAY. AHEAD OF THE FRONT
AND THE RAIN...TEMPERATURES ARE LIKELY TO CLIMB INTO THE 60S FRIDAY
AFTERNOON. -BLAES
&&
.AVIATION /12Z SATURDAY THROUGH WEDNESDAY/...
AS OF 650 AM SATURDAY...
VFR CONDITIONS CONTINUE THROUGH MUCH OF THE 12Z VALID TAF PERIOD.
WINDS REMAIN NOTICEABLE DURING THE EARLY MORNING IN THE TIGHTER
GRADIENT ON THE EAST SIDE OF THE RIDGE AXIS...AND THE KRAX WSR-88D
SHOWED WINDS OF 40KT EARLIER JUST ABOVE 2K FEET...BUT THESE WINDS
HAVE SINCE DIMINISHED ALMOST IN HALF SINCE 06Z. MODEL GUIDANCE SHOWS
SUCH WINDS CONTINUING TO DECREASE SOME DURING THE MORNING...BUT
THESE COULD TRANSLATE TO A FEW WIND GUSTS IN THE TEENS KTS AFTER
SUNRISE WITH EVEN MINIMAL MIXING AT KRDU AND ESPECIALLY KFAY AND
KRWI. AS HIGH PRESSURE SETTLES OVERHEAD FOR THIS EVENING...WINDS
SHOULD BECOME LIGHT. AS LOW-LEVEL MOISTURE INCREASES THIS EVENING
AND OVERNIGHT...THERE IS THE POTENTIAL FOR AT LEAST A PERIOD OF MVFR
CEILINGS PARTICULARLY TOWARD KFAY WITH A LESSER LIKELIHOOD TOWARD
KRDU AND KRWI.
BEYOND THE 12Z VALID TAF PERIOD...SUB-VFR CONDITIONS ARE POSSIBLE
EARLY SUNDAY MAINLY TOWARD KFAY...AND SUCH CONDITIONS ARE QUITE
POSSIBLE SUNDAY NIGHT MAINLY EAST AND SOUTHEAST OF THE TRIAD AS
MOISTURE INCREASES...ALONG WITH A CHANCE OF RAIN MAINLY EAST AND
SOUTHEAST OF THE TRIAD. THE PROBABILITY OF SUB-VFR CONDITIONS
INCREASES LATE SUNDAY NIGHT INTO MONDAY...AGAIN BEST EAST AND
SOUTHEAST OF THE TRIAD...WITH IMPROVING CONDITIONS FOR TUESDAY
CONTINUING INTO WEDNESDAY.
&&
.RAH WATCHES/WARNINGS/ADVISORIES...
NONE
&&
$$
SYNOPSIS...VINCENT
NEAR TERM...DJF
SHORT TERM...DJF
LONG TERM...BLAES
AVIATION...DJF
AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE RALEIGH NC 650 AM
EST SAT NOV 30 2013
.SYNOPSIS...
SURFACE HIGH PRESSURE REMAINS IN PLACE THROUGH THE DAY SUNDAY.
MOISTURE INCREASES AHEAD OF LOW PRESSURE THAT GRADUALLY STRENGTHENS
JUST OFF THE CAROLINA COAST LATE SUNDAY NIGHT THROUGH TUESDAY. HIGH
PRESSURE RETURNS FOR THE MIDDLE OF THE WEEK.
&&
.NEAR TERM /THROUGH TODAY/...
AS OF 650 AM SATURDAY...
THE LATEST SURFACE ANALYSIS SHOWED THE AXIS OF SURFACE HIGH PRESSURE
NORTHEAST TO SOUTHWEST ACROSS CENTRAL NORTH CAROLINA...AND DURING
THE DAY THE RIDGE SETTLES SLOWLY SOUTH WHICH SHOULD RELAX THE
GRADIENT FOR THE LATE DAY AND OVERNIGHT. A MODERATE MID-LEVEL
SHORTWAVE WAS OBSERVED ON WATER VAPOR IMAGERY MOVING EAST FROM
MISSOURI AND ILLINOIS TOWARD THE MID-ATLANTIC...WITH A MID-LEVEL
TROUGH PASSING EAST OF THE STATE AS OF THIS WRITING. 1000-850MB
THICKNESSES ARE FORECAST VERY SIMILAR TO THOSE THAT OCCURRED
FRIDAY...WHEN HIGHS WERE AROUND 50 TO THE MID 50S. HOWEVER...
GUIDANCE IS VERY CONSISTENT IN SHOWING HIGHS TODAY ROUGHLY A
CATEGORY...POSSIBLY EVEN TWO...COOLER. NAM AND GFS BUFR SOUNDINGS
MAINTAIN STRONG SUBSIDENCE AND LIMITED MIXING POTENTIAL...AND AHEAD
OF THE MODEST MID-LEVEL SHORTWAVE TO OUR WEST THAT BOTH THE NAM AND
THE GFS MOVE ACROSS CENTRAL NORTH CAROLINA LATE THIS AFTERNOON AND
OVERNIGHT...DIFFLUENCE ALOFT INCREASES AS A 90KT 300MB JET
APPROACHES FROM THE WEST...WITH POSSIBLY JUST ENOUGH HIGH CLOUDS TO
TEMPER HIGHS SOMEWHAT. WILL LEAN TOWARD WARMER GUIDANCE FOR HIGHS IN
THE MID 40S TO LOWER 50S. ESPECIALLY ALONG AND EAST OF U.S. 1 THERE
SHOULD BE JUST A FEW WIND GUSTS IN THE TEENS KNOTS WITH MIXING LATER
THIS MORNING BEFORE THE SURFACE RIDGING SETTLES SOUTH. 925MB WINDS
ARE FORECAST ONLY TO AROUND 15KT DURING THE DAY.
THE LATEST RAP...ALONG WITH THE HRRR WRF...FORECAST AN INCREASE IN
LOW-LEVEL MOISTURE FROM THE SOUTHEAST LATE IN THE DAY. THIS MAY BE
REASONABLE...AS THE SATELLITE FOG PRODUCT SHOWED AREAS OF LOW CLOUDS
JUST OFFSHORE FROM SOUTHEAST NORTH CAROLINA EARLY THIS MORNING. HAVE
ADDED SOME CLOUD COVER TO THE GRIDDED AND WORDED FORECASTS
PARTICULARLY TOWARD KCTZ DURING THE AFTERNOON.
&&
.SHORT TERM /TONIGHT THROUGH SUNDAY NIGHT/...
AS OF 650 AM SATURDAY...
SURFACE HIGH PRESSURE SHOULD BE DIRECTLY OVERHEAD OVERNIGHT KEEPING
THE GRADIENT VERY RELAXED. THE POTENTIAL FOR A QUITE CHILLY NIGHT
WOULD EXIST BUT THE COMBINATION OF SOME HIGH CLOUDS AND THE GFS
FORECAST OF INCREASING 850MB MOISTURE FROM THE SOUTH AND SOUTHWEST
MAY ACT TO KEEP TEMPERATURES CLOSE TO THE GUIDANCE LOWS OVERNIGHT.
THE LATEST SATELLITE FOG PRODUCT SHOWS LOW-LEVEL MOISTURE MOVING
WEST TOWARD THE SOUTH CAROLINA COAST...AND LOW-LEVEL ISENTROPIC
FORECASTS ALONG WITH THE INCREASING 850MB MOISTURE SUPPORT AN
INCREASE IN CLOUD COVER TO PARTLY-TO-MOSTLY CLOUDY PARTICULARLY
ALONG AND SOUTH OF ABOUT INTERSTATE 85 DURING THE OVERNIGHT HOURS.
THE TIMING OF THIS IS...OF COURSE...CRITICAL TO THE OVERNIGHT
TEMPERATURE FORECAST...BUT FOR THIS FORECAST WILL LEAN TOWARD THE
COOLER MOS GUIDANCE IN THE TRIAD AND THE WARMER MOS GUIDANCE
ELSEWHERE.
K INDICES SLOWLY RISE SUNDAY...WITH PRECIPITABLE WATER VALUES RISING
LATE SUNDAY TO BETWEEN 0.75 AND ONE INCH...ABOVE NORMAL FOR VERY
EARLY DECEMBER AT ABOUT THE 75TH PERCENTILE. LIFT STARTS TO INCREASE
LATE SUNDAY AND PARTICULARLY SUNDAY NIGHT AS ISENTROPIC LIFT ON THE
300K SURFACE INCREASES...WITH THE BEST POTENTIAL VORTICITY ON THE
1.5PVU SURFACE FORECAST BY THE GFS ALONG AND SOUTH OF ABOUT U.S. 64
LATE SUNDAY THROUGH SUNDAY NIGHT. SURFACE DEPICTIONS OF THE NAM AND
GFS DIFFER AND ARE FAIRLY CONSISTENT WITH THEMSELVES OVER THE LAST
TWO OR THREE RUNS...WITH THE NAM SHOWING A WEAK SURFACE LOW JUST OFF
THE SOUTH CAROLINA COAST SUNDAY NIGHT WHILE THE GFS FORECASTS MORE
OF AN INVERTED TROUGH BEFORE SURFACE LOW PRESSURE STRENGTHENS
OFFSHORE. REGARDNESS...QPF AND MOS GUIDANCE POPS ARE SIMILAR...
KEEPING MOST CHANCES FOR PRECIPITATION AT BAY SUNDAY AND INCREASING
CHANCES OVER MOST OF CENTRAL NORTH CAROLINA SUNDAY NIGHT. WILL NOTE
A SLIGHT CHANCE OF RAIN MAINLY OVER THE SANDHILLS AND SOUTHERN
COASTAL PLAIN SUNDAY WHERE THE BEST LOW-LEVEL MOISTURE SHOULD RESIDE
AS POTENTIAL VORTICITY INCREASES...WITH A CHANCE OF RAIN SUNDAY
NIGHT MAINLY ALONG AND EAST OF A LINE FROM ABOUT KIXA TO KAFP WITH A
SLIGHT CHANCE NORTH OF THAT LINE. DEBATED WHETHER OR NOT TO INCLUDE
A SLIGHT CHANCE IN THE TRIAD AND FOR THIS FORECAST WILL SHOW A VERY
LOW SLIGHT CHANCE THERE OVERNIGHT SUNDAY...THOUGH THIS COULD END UP
BEING OVERDONE WITH SUFFICIENT MOISTURE AND LIFT REMAINING JUST
EAST. SURFACE WET BULB TEMPERATURES AND PARTIAL THICKNESSES SUPPORT
ALL LIQUID.
ONCE AGAIN 1000-850MB THICKNESSES WOULD SUPPORT HIGHS SUNDAY ABOVE
MOS GUIDANCE...BUT GIVEN THE EXPECTED CLOUD COVER...WILL FORECAST
HIGHS AS A BLEND OF MAV AND MET MOS GUIDANCE FOR A FAIRLY UNIFORM
LOWER 50S IN MOST LOCATIONS. OVERNIGHT SUNDAY...IF IT REMAINS DRY IN
THE TRIAD LOWS SHOULD BE NEAR THE WARMER GUIDANCE...WHILE WHERE IT
RAINS TEMPERATURES WOULD APPROACH THE DEW POINT. THIS COINCIDES WITH
A BLEND OF MOS GUIDANCE...ALTHOUGH HIGHER THAN GUIDANCE TOWARD
KRWI...FOR LOWS IN THE MID TO UPPER 30S NORTHWEST...TO MID 40S
TOWARD KCTZ.
&&
.LONG TERM /MONDAY THROUGH FRIDAY/...
AS OF 235 AM SATURDAY...
ON MONDAY A LOW AMPLITUDE NORTHERN STREAM SHORTWAVE DROPS INTO THE
THE DEEP SOUTH AS A SHEARING SOUTHERN STREAM SYSTEM WITH A 250MB JET
OF 140 KTS PHASE TOGETHER BEFORE THE TROUGH AXIS MOVES OFF THE
SOUTHEAST COAST MONDAY NIGHT. THE TROUGH BECOMES NEGATIVELY TILTED
AND INITIATES SURFACE CYCLOGENESIS MONDAY NIGHT AND TUESDAY. RECENT
NWP TRENDS HAVE SUGGESTED A LESS AMPLIFIED SYSTEM WHILE PRODUCING A
BIT MORE QPF ACROSS MAINLY SOUTHEASTERN NC. IT REMAINS DIFFICULT AND
CONFIDENCE IS LOW REGARDING HOW FAR NORTH AND WEST PRECIPITATION
WILL SPREAD ACROSS CENTRAL NC BUT CONFIDENCE IS GROWING THAT SOME
LIGHT PRECIPITATION WILL FALL ACROSS THE SOUTHERN COASTAL PLAIN AND
SANDHILLS REGION. NWP CONSENSUS SHOWS THE DEEPEST MOISTURE AND
STRONGEST FORCING WILL BE CONFINED TO SOUTHEASTERN PORTIONS OF THE
RAH CWA WITH RAPIDLY DECREASING RAIN CHANCES ACROSS THE NORTHERN AND
WESTERN PIEDMONT. ISENTROPIC ANALYSIS DEPICTS THE PATTERN WELL WITH
A FAIRLY NARROW CORRIDOR OF LIFT/SATURATION THAT SLIDES MAINLY
ACROSS SOUTHERN AND EASTERN NC. PRECIPITATION CHANCES QUICKLY TAIL
OFF FROM WEST TO EAST ON MONDAY NIGHT. THE AIR MASS AHEAD OF THE
SYSTEM WILL HAVE MODIFIED AND THE PRECIPITATION WILL FALL AS RAIN.
GIVEN THE MODIFICATION OF THE AIR MASS AND THE LIGHT PRECIPITATION
CHANCES...DO NOT EXPECT A SIGNIFICANT CAD EVENT TO OCCUR. HIGHS
MONDAY WILL RANGE IN THE 49-56 RANGE WITH MAX TEMPERATURES DEPENDENT
ON THE LOCATION AND INTENSITY OF THE PRECIPITATION.
AFTER THE UPPER TROUGH AXIS MOVES OFFSHORE...THE FLOW ALOFT BECOMES
MORE NORTHWESTERLY. ANOTHER DISTURBANCE IN THE FLOW AND SOME
RESIDUAL MOISTURE SHOULD BE SUFFICIENT TO PRODUCE SOME CLOUDINESS ON
TUESDAY BUT OTHERWISE FAIR CONDITIONS ARE EXPECTED WITH HIGHS IN THE
LOWER TO MID 50S.
THE FLOW FLATTENS ON TUESDAY NIGHT AND HEIGHTS RISE ON WEDNESDAY
INTO THURSDAY WITH INCREASING HIGH CLOUDS LATE WEDNESDAY AND A FAIR
AMOUNT OF CLOUDS EXPECTED ON THURSDAY. EXPECT DRY WEATHER THROUGH AT
LEAST THURSDAY AFTERNOON AS THE RIDGE AXIS BUILDS OVERHEAD.
MODERATING TEMPERATURES ARE EXPECTED ON THURSDAY INTO FRIDAY WITH
HIGHS IN THE MID TO UPPER 50S ON WEDNESDAY WARMING INTO THE UPPER
50S TO LOWER 60S ON THURSDAY WITH MORNING LOWS IN THE MID 30S TO
AROUND 40.
A LONGWAVE TROUGH DEVELOPS OVER THE WESTERN U.S. LATE THURSDAY INTO
FRIDAY AS AN ARCTIC AIRMASS DROPS INTO THE NORTHERN ROCKIES AND
NORTHERN PLAINS. AN INCREASINGLY MOIST SOUTHERLY TO SOUTHWESTERLY
FLOW DEVELOPS ACROSS THE CENTRAL U.S. AS THE TROUGH PUSHES EAST ON
FRIDAY. THE ASSOCIATED COLD FRONT REACHES THE WESTERN APPALACHIANS
ON FRIDAY MORNING. THERE ARE TIMING DIFFERENCES AMONG THE GUIDANCE
REGARDING THE EASTWARD ADVANCEMENT OF THE FRONT AND THE ASSOCIATED
PRECIPITATION WITH WPC PREFERRING A GEFS MEAN AND EC ENS MEAN.
REGARDLESS...THE THREAT OF RAIN WILL ARRIVE WITH LOW PROBABILITIES
IN THE WEST LATE THURSDAY NIGHT. POPS WILL INCREASE FROM WEST TO
EAST FRIDAY AND FRIDAY NIGHT WITH THE BEST CHANCE OF RAIN AT THIS
POINT APPEARING TO BE FRIDAY NIGHT AND SATURDAY. AHEAD OF THE FRONT
AND THE RAIN...TEMPERATURES ARE LIKELY TO CLIMB INTO THE 60S FRIDAY
AFTERNOON. -BLAES
&&
.AVIATION /12Z SATURDAY THROUGH WEDNESDAY/...
AS OF 650 AM SATURDAY...
VFR CONDITIONS CONTINUE THROUGH MUCH OF THE 12Z VALID TAF PERIOD.
WINDS REMAIN NOTICEABLE DURING THE EARLY MORNING IN THE TIGHTER
GRADIENT ON THE EAST SIDE OF THE RIDGE AXIS...AND THE KRAX WSR-88D
SHOWED WINDS OF 40KT EARLIER JUST ABOVE 2K FEET...BUT THESE WINDS
HAVE SINCE DIMINISHED ALMOST IN HALF SINCE 06Z. MODEL GUIDANCE SHOWS
SUCH WINDS CONTINUING TO DECREASE SOME DURING THE MORNING...BUT
THESE COULD TRANSLATE TO A FEW WIND GUSTS IN THE TEENS KTS AFTER
SUNRISE WITH EVEN MINIMAL MIXING AT KRDU AND ESPECIALLY KFAY AND
KRWI. AS HIGH PRESSURE SETTLES OVERHEAD FOR THIS EVENING...WINDS
SHOULD BECOME LIGHT. AS LOW-LEVEL MOISTURE INCREASES THIS EVENING
AND OVERNIGHT...THERE IS THE POTENTIAL FOR AT LEAST A PERIOD OF MVFR
CEILINGS PARTICULARLY TOWARD KFAY WITH A LESSER LIKELIHOOD TOWARD
KRDU AND KRWI.
BEYOND THE 12Z VALID TAF PERIOD...SUB-VFR CONDITIONS ARE POSSIBLE
EARLY SUNDAY MAINLY TOWARD KFAY...AND SUCH CONDITIONS ARE QUITE
POSSIBLE SUNDAY NIGHT MAINLY EAST AND SOUTHEAST OF THE TRIAD AS
MOISTURE INCREASES...ALONG WITH A CHANCE OF RAIN MAINLY EAST AND
SOUTHEAST OF THE TRIAD. THE PROBABILITY OF SUB-VFR CONDITIONS
INCREASES LATE SUNDAY NIGHT INTO MONDAY...AGAIN BEST EAST AND
SOUTHEAST OF THE TRIAD...WITH IMPROVING CONDITIONS FOR TUESDAY
CONTINUING INTO WEDNESDAY.
&&
.RAH WATCHES/WARNINGS/ADVISORIES...
NONE
&&
$$
SYNOPSIS... DJF
NEAR TERM...DJF
SHORT TERM...DJF
LONG TERM...BLAES
AVIATION...DJF
AREA FORECAST DISCUSSION
NWS GRAND FORKS ND
946 AM CST SAT NOV 30 2013
.UPDATE...
ISSUED AT 946 AM CST SAT NOV 30 2013
LOWERED HIGHS FOR TODAY ACROSS THE NORTHWESTERN COUNTIES AND
DROPPED THEM EVEN A DEGREE OR SO DOWN TO FARGO. CLEAR SKIES
ALLOWED TEMPS AROUND KDVL TO DROP INTO THE LOWER TEENS...AND WITH
STRATUS MOVING IN THERE WILL BE NOT TOO MUCH RISE THIS AFTERNOON.
AT THIS TIME THE SOUTHWESTERN CWA COULD STILL SEE SOME SUN AND
CLIMB INTO THE MID 30S...BUT THERE ARE MORE MID CLOUDS MOVING IN
FROM THE WEST. MADE SOME FURTHER TWEAKS TO CLOUDS AND WILL KEEP AN
EYE ON TEMPS IN CASE THEY NEED TO BE DROPPED MORE LATER ON TODAY.
UPDATE ISSUED AT 644 AM CST SAT NOV 30 2013
WILL NEED TO INCREASE SKY TODAY. THE RAP GUIDANCE IS VERIFYING THE
BEST...SHOWING THE LOW LEVEL CIGS FROM CANADA ADVECTING INTO THE
FORECAST AREA. WILL FOLLOW THE 09Z RAP FOR ARRIVAL TIMES. WILL
ALSO KEEP THE REGION CLOUDY THROUGH THE OVERNIGHT HOURS.
FORECASTED MAX TEMPS TODAY MAY BE A BIT HIGH...BUT SHOULD BE IN
THE BALL PARK. FORECASTED MIN TEMPS TONIGHT ARE LIKELY TOO COLD
(IF CLOUDS STICK AROUND AS EXPECTED). WILL CONCENTRATE ON SKY FOR
THIS UPDATE...AND WORRY ABOUT TEMPS WITH THE NEXT UPDATES.
&&
.SHORT TERM...(TODAY THROUGH SUNDAY)
ISSUED AT 337 AM CST SAT NOV 30 2013
00Z MODELS INITIALIZED WITH MINIMAL ERRORS AND ARE IN GOOD
AGREEMENT THROUGH SUNDAY. THE CHALLENGE FOR TODAY WILL BE
TEMPERATURES AND CLOUD COVER. THE CHALLENGE FOR SUNDAY WILL BE -SN
CHANCES.
TODAY-TONIGHT...WEAK COLD FRONT WILL BE THROUGH THE REGION WHICH
SHOULD LEAD TO SLIGHTLY COOLER TEMPERATURES THAN YESTERDAY. THE
MID-LEVEL CLOUDS ALONG AND AHEAD OF THIS FEATURE WILL MOVE
SOUTH...BUT WILL NEED TO WATCH THE LOW-LEVEL CIGS APPROACHING FROM
THE NORTH. 06Z RAP IS MOST AGGRESSIVE BRINGING THESE CIGS INTO THE
ENTIRE FA...WHILE MOST OTHER GUIDANCE SUGGESTS ONLY PORTIONS OF NW
MN WILL BE AFFECTED. WILL SIDE WITH THE MAJORITY...AND TAKE A
CLOSER LOOK AT THE 7AM UPDATE.
SUNDAY...00Z MODELS HAVE SLOWED THE SHORTWAVE BRINGING -SN
CHANCES...ADJUSTED POPS ACCORDINGLY. MUCH OF SUNDAY SHOULD BE DRY
(UNTIL THE EVENING HOURS).
.LONG TERM...(SUNDAY NIGHT THROUGH FRIDAY)
ISSUED AT 337 AM CST SAT NOV 30 2013
SUNDAY NIGHT-MONDAY NIGHT...00Z MODELS BEGIN TO DIVERGE...WITH THE
ECMWF/GEM/UKMET DIGGING THE UPPER LOW INTO THE NW CONUS BY 12Z
TUE...AND THE NAM/GFS BRINGING THIS FEATURE INTO MONTANA/WESTERN
DAKOTAS. THE ECMWF/GEM/UKMET HAVE BEEN THE MORE CONSISTENT
MODELS...AND ARE SUPPORTED BY ENSEMBLES (WILL FOLLOW FOR FORECAST
DETAILS). THERE WILL BE A COUPLE LEAD SHORTWAVES EJECTING FROM THE
MAIN UPPER TROUGH. THE FIRST WILL MOVE THROUGH THE REGION SUNDAY
NIGHT...AND THE SECOND MONDAY AFTERNOON/NIGHT. SINCE THERE HAVE
BEEN A FEW MODEL RUNS INDICATING THESE FEATURES...WILL INCREASE
POPS TO LIKELY AND ATTEMPT TO TIME THESE FEATURES THROUGH THE
REGION. THE FIRST WAVE IS WEAKER...AND SHOULD HAVE LESS AVAILABLE
MOISTURE. MESOSCALE FORCING IS ALSO WEAK...SO UP TO AN INCH OF
SNOWFALL APPEARS POSSIBLE (MAYBE 2 INCHES). THE SECOND WAVE IS
STRONGER...WITH MORE AVAILABLE MOISTURE (PWATS APPROACHING 0.5
INCHES). MODELS INDICATE A DEFINED CIRCULATION AT 850MB (AND A
WEAK 700MB LOW) PROPAGATING FROM NW ND INTO SE ND ON
MONDAY...LOSING DEFINITION MONDAY NIGHT AS IT PROPAGATES FURTHER
TO THE SE. ASSOCIATED WARM AIR ADVECTION/DEFORMATION COMBINED
WITH THE 0.5 INCH PWATS SHOULD LEAD TO A FEW INCHES OF SNOWFALL.
MODELS INDICATE 0.25-0.40 INCHES QPF ACROSS ALL BUT THE NE
FA...AND COMBINED WITH 12:1-13:1 SNOW RATIOS WOULD LEAD TO AN AREA
OF 3-5 INCHES OF SNOW. P-TYPE WILL BE ALL SNOW IF THE EXPECTED
SOLUTION VERIFIES. THE NAM/SREF/GFS HAVE WARMER MID-LEVEL
TEMPERATURES SINCE THE UPPER WAVE IS CLOSER TO THE REGION (LOW
LEVEL SOUTHERLY FLOW IS STRONGER)...AND WOULD LEAD TO FZRA/RA
POTENTIAL (BUT THIS PROBABILITY SEEMS VERY LOW ATTM).
TUESDAY-FRIDAY...A VERY WINTRY PERIOD IS IN STORE...WITH THE MAIN
FOCUS INITIALLY BEING SNOW POTENTIAL THROUGH MID-WEEK FOLLOWED BY
A COLD ARCTIC AIR MASS SPILLING SOUTH.
MODEL SPREAD CONTINUES TO BE SIGNIFICANT...ALTHOUGH THE ECMWF HAS
SHOWN BETTER CONSISTENCY OVER THE PAST FEW RUNS...SO HAVE TRENDED A
BIT IN THAT DIRECTION. THE 00Z GFS/ECMWF BOTH BRING THE UPPER TROUGH
EASTWARD INTO THE PLAINS WED/THU. HOWEVER...A CHALLENGE CONTINUES TO
BE TIMING OF EMBEDDED WAVES. THE ECMWF REMAINS DEEPEST AND FARTHEST
WEST WITH SFC LOW DEVELOPMENT FROM THE CENTRAL PLAINS NORTHEAST INTO
ONTARIO IN CONJUNCTION WITH A STRONG SHORTWAVE TROUGH ASSOCIATED
WITH THE LIFTING UPPER LOW...WHILE THE GFS IS MORE PROGRESSIVE WITH
A WEAKER SFC LOW ASSOCIATED WITH A LEAD WAVE. THUS...THE ECMWF AND
TO A LESSER EXTENT THE GEM ARE MORE AGGRESSIVE WITH QPF. THE 500 MB
GFS ENSEMBLE MEAN HEIGHT FIELD GENERALLY SUPPORTS THE ECMWF BROADLY.
CONFIDENCE STILL IS RATHER LOW REGARDING THE PLACEMENT AND MAGNITUDE
OF SNOWFALL...ALTHOUGH THE MID-WEEK PERIOD WILL CONTINUE TO BEAR
WATCHING FOR ACCUMULATING SNOWFALL.
ARCTIC AIR WILL BLAST SOUTH DURING THE LATTER PART OF THE
WEEK INTO NEXT WEEKEND. THE ECMWF CONTINUES TO INDICATE 925 MB TEMPS
DOWN TO -20 TO -25C THURSDAY/FRIDAY BEHIND INITIAL SURGE OF COLD
ADVECTION. BLUSTERY WINDS WILL COMBINE WITH VERY COLD TEMPS TO
PRODUCE POTENTIALLY HAZARDOUS WIND CHILLS AT TIMES.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SUNDAY MORNING)
ISSUED AT 644 AM CST SAT NOV 30 2013
MAJOR CHANGE WITH THE 12Z TAF ISSUANCE TO BRING MVFR CIGS INTO THE
REGION TODAY. USED THE 09Z RAP FOR HELP WITH ARRIVAL TIMES.
SATELLITE IMAGERY INDICATES THESE CIGS CONTINUE TO ADVECT
SOUTHWARD FROM CANADA...WITH THE RAP GUIDANCE HANDLING THIS
SCENARIO THE BEST. THESE CIGS WILL LIKELY REMAIN THROUGH THE
OVERNIGHT HOURS.
&&
.FGF WATCHES/WARNINGS/ADVISORIES...
ND...NONE.
MN...NONE.
&&
$$
UPDATE...JR
SHORT TERM...TG
LONG TERM...TG/MAKOWSKI
AVIATION...TG
AREA FORECAST DISCUSSION
NWS GRAND FORKS ND
644 AM CST SAT NOV 30 2013
.UPDATE...
ISSUED AT 644 AM CST SAT NOV 30 2013
WILL NEED TO INCREASE SKY TODAY. THE RAP GUIDANCE IS VERIFYING THE
BEST...SHOWING THE LOW LEVEL CIGS FROM CANADA ADVECTING INTO THE
FORECAST AREA. WILL FOLLOW THE 09Z RAP FOR ARRIVAL TIMES. WILL
ALSO KEEP THE REGION CLOUDY THROUGH THE OVERNIGHT HOURS.
FORECASTED MAX TEMPS TODAY MAY BE A BIT HIGH...BUT SHOULD BE IN
THE BALL PARK. FORECASTED MIN TEMPS TONIGHT ARE LIKELY TOO COLD
(IF CLOUDS STICK AROUND AS EXPECTED). WILL CONCENTRATE ON SKY FOR
THIS UPDATE...AND WORRY ABOUT TEMPS WITH THE NEXT UPDATES.
&&
.SHORT TERM...(TODAY THROUGH SUNDAY)
ISSUED AT 337 AM CST SAT NOV 30 2013
00Z MODELS INITIALIZED WITH MINIMAL ERRORS AND ARE IN GOOD
AGREEMENT THROUGH SUNDAY. THE CHALLENGE FOR TODAY WILL BE
TEMPERATURES AND CLOUD COVER. THE CHALLENGE FOR SUNDAY WILL BE -SN
CHANCES.
TODAY-TONIGHT...WEAK COLD FRONT WILL BE THROUGH THE REGION WHICH
SHOULD LEAD TO SLIGHTLY COOLER TEMPERATURES THAN YESTERDAY. THE
MID-LEVEL CLOUDS ALONG AND AHEAD OF THIS FEATURE WILL MOVE
SOUTH...BUT WILL NEED TO WATCH THE LOW-LEVEL CIGS APPROACHING FROM
THE NORTH. 06Z RAP IS MOST AGGRESSIVE BRINGING THESE CIGS INTO THE
ENTIRE FA...WHILE MOST OTHER GUIDANCE SUGGESTS ONLY PORTIONS OF NW
MN WILL BE AFFECTED. WILL SIDE WITH THE MAJORITY...AND TAKE A
CLOSER LOOK AT THE 7AM UPDATE.
SUNDAY...00Z MODELS HAVE SLOWED THE SHORTWAVE BRINGING -SN
CHANCES...ADJUSTED POPS ACCORDINGLY. MUCH OF SUNDAY SHOULD BE DRY
(UNTIL THE EVENING HOURS).
.LONG TERM...(SUNDAY NIGHT THROUGH FRIDAY)
ISSUED AT 337 AM CST SAT NOV 30 2013
SUNDAY NIGHT-MONDAY NIGHT...00Z MODELS BEGIN TO DIVERGE...WITH THE
ECMWF/GEM/UKMET DIGGING THE UPPER LOW INTO THE NW CONUS BY 12Z
TUE...AND THE NAM/GFS BRINGING THIS FEATURE INTO MONTANA/WESTERN
DAKOTAS. THE ECMWF/GEM/UKMET HAVE BEEN THE MORE CONSISTENT
MODELS...AND ARE SUPPORTED BY ENSEMBLES (WILL FOLLOW FOR FORECAST
DETAILS). THERE WILL BE A COUPLE LEAD SHORTWAVES EJECTING FROM THE
MAIN UPPER TROUGH. THE FIRST WILL MOVE THROUGH THE REGION SUNDAY
NIGHT...AND THE SECOND MONDAY AFTERNOON/NIGHT. SINCE THERE HAVE
BEEN A FEW MODEL RUNS INDICATING THESE FEATURES...WILL INCREASE
POPS TO LIKELY AND ATTEMPT TO TIME THESE FEATURES THROUGH THE
REGION. THE FIRST WAVE IS WEAKER...AND SHOULD HAVE LESS AVAILABLE
MOISTURE. MESOSCALE FORCING IS ALSO WEAK...SO UP TO AN INCH OF
SNOWFALL APPEARS POSSIBLE (MAYBE 2 INCHES). THE SECOND WAVE IS
STRONGER...WITH MORE AVAILABLE MOISTURE (PWATS APPROACHING 0.5
INCHES). MODELS INDICATE A DEFINED CIRCULATION AT 850MB (AND A
WEAK 700MB LOW) PROPAGATING FROM NW ND INTO SE ND ON
MONDAY...LOSING DEFINITION MONDAY NIGHT AS IT PROPAGATES FURTHER
TO THE SE. ASSOCIATED WARM AIR ADVECTION/DEFORMATION COMBINED
WITH THE 0.5 INCH PWATS SHOULD LEAD TO A FEW INCHES OF SNOWFALL.
MODELS INDICATE 0.25-0.40 INCHES QPF ACROSS ALL BUT THE NE
FA...AND COMBINED WITH 12:1-13:1 SNOW RATIOS WOULD LEAD TO AN AREA
OF 3-5 INCHES OF SNOW. P-TYPE WILL BE ALL SNOW IF THE EXPECTED
SOLUTION VERIFIES. THE NAM/SREF/GFS HAVE WARMER MID-LEVEL
TEMPERATURES SINCE THE UPPER WAVE IS CLOSER TO THE REGION (LOW
LEVEL SOUTHERLY FLOW IS STRONGER)...AND WOULD LEAD TO FZRA/RA
POTENTIAL (BUT THIS PROBABILITY SEEMS VERY LOW ATTM).
TUESDAY-FRIDAY...A VERY WINTRY PERIOD IS IN STORE...WITH THE MAIN
FOCUS INITIALLY BEING SNOW POTENTIAL THROUGH MID-WEEK FOLLOWED BY
A COLD ARCTIC AIR MASS SPILLING SOUTH.
MODEL SPREAD CONTINUES TO BE SIGNIFICANT...ALTHOUGH THE ECMWF HAS
SHOWN BETTER CONSISTENCY OVER THE PAST FEW RUNS...SO HAVE TRENDED A
BIT IN THAT DIRECTION. THE 00Z GFS/ECMWF BOTH BRING THE UPPER TROUGH
EASTWARD INTO THE PLAINS WED/THU. HOWEVER...A CHALLENGE CONTINUES TO
BE TIMING OF EMBEDDED WAVES. THE ECMWF REMAINS DEEPEST AND FARTHEST
WEST WITH SFC LOW DEVELOPMENT FROM THE CENTRAL PLAINS NORTHEAST INTO
ONTARIO IN CONJUNCTION WITH A STRONG SHORTWAVE TROUGH ASSOCIATED
WITH THE LIFTING UPPER LOW...WHILE THE GFS IS MORE PROGRESSIVE WITH
A WEAKER SFC LOW ASSOCIATED WITH A LEAD WAVE. THUS...THE ECMWF AND
TO A LESSER EXTENT THE GEM ARE MORE AGGRESSIVE WITH QPF. THE 500 MB
GFS ENSEMBLE MEAN HEIGHT FIELD GENERALLY SUPPORTS THE ECMWF BROADLY.
CONFIDENCE STILL IS RATHER LOW REGARDING THE PLACEMENT AND MAGNITUDE
OF SNOWFALL...ALTHOUGH THE MID-WEEK PERIOD WILL CONTINUE TO BEAR
WATCHING FOR ACCUMULATING SNOWFALL.
ARCTIC AIR WILL BLAST SOUTH DURING THE LATTER PART OF THE
WEEK INTO NEXT WEEKEND. THE ECMWF CONTINUES TO INDICATE 925 MB TEMPS
DOWN TO -20 TO -25C THURSDAY/FRIDAY BEHIND INITIAL SURGE OF COLD
ADVECTION. BLUSTERY WINDS WILL COMBINE WITH VERY COLD TEMPS TO
PRODUCE POTENTIALLY HAZARDOUS WIND CHILLS AT TIMES.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SUNDAY MORNING)
ISSUED AT 644 AM CST SAT NOV 30 2013
MAJOR CHANGE WITH THE 12Z TAF ISSUANCE TO BRING MVFR CIGS INTO THE
REGION TODAY. USED THE 09Z RAP FOR HELP WITH ARRIVAL TIMES.
SATELLITE IMAGERY INDICATES THESE CIGS CONTINUE TO ADVECT
SOUTHWARD FROM CANADA...WITH THE RAP GUIDANCE HANDLING THIS
SCENARIO THE BEST. THESE CIGS WILL LIKELY REMAIN THROUGH THE
OVERNIGHT HOURS.
&&
.FGF WATCHES/WARNINGS/ADVISORIES...
ND...NONE.
MN...NONE.
&&
$$
UPDATE...TG
SHORT TERM...TG
LONG TERM...TG/MAKOWSKI
AVIATION...TG
AREA FORECAST DISCUSSION...UPDATED
NWS ABERDEEN SD
543 AM CST SAT NOV 30 2013
.UPDATE...
12Z AVIATION DISCUSSION BELOW...
&&
.PREVIOUS DISCUSSION...
.SHORT TERM...TODAY THROUGH MONDAY
CHANCES FOR PRECIPITATION AS WELL AS P-TYPE WILL BE THE FORECAST
CHALLENGES.
A WEAK MID LEVEL SHORT WAVE CURRENTLY OVER MONTANA WILL TRACK
SOUTHEASTWARD ACROSS THE REGION TODAY...BRINGING PARTLY CLOUDY
SKIES TO THE CWA. THE PAST FEW RUNS OF THE RUC AND THE NSSL WRF
BOTH SHOW SOME LIGHT RAIN FOR THE FAR NW PORTION OF THE
CWA...PERHAPS REACHING KMBG BY THIS AFTERNOON. THUS HAVE ADDED A
LOW POP.
ANOTHER MID LEVEL SHORT WAVE AND FRONTAL BOUNDARY WILL TRACK
ACROSS THE REGION ON SUNDAY. MODELS HAVE SIGNIFICANTLY SLOWED DOWN
THE PROGRESSION OF THE TROUGH...WITH PCPN NOT REACHING THE JAMES
RIVER VALLEY UNTIL AFTER 18Z. IT STILL APPEARS AS THOUGH THE
LEADING EDGE OF THE PCPN WILL FALL AS ALL SNOW. HOWEVER WITH WAA
QUICKLY PUSHING IN ON THE BACK SIDE...THE SNOW WILL TRANSITION
OVER TO ALL RAIN. THIS SYSTEM DOES NOT CONTAIN A GREAT DEAL OF LOW
LEVEL MOISTURE SO WILL MAINTAIN CHC POP ALONG THE ND/SD BORDER FOR
NOW. A MUCH STRONGER STORM SYSTEM WILL BEGIN IMPACTING THE REGION
ON MONDAY. HOWEVER MODEL ARE NOT IN A REAL GOOD AGREEMENT WITH THE
OVERALL PLACEMENT OF THIS MID LEVEL CLOSED LOW...WHICH LEADS TO A
LOW FORECASTER CONFIDENCE. EVEN WITH A DISAGREEMENT ON THE PLACEMENT
THERE IS A GENERAL CONSENSUS THAT TEMPERATURES WILL BE WARM ENOUGH
TO SUPPORT A MOSTLY RAIN EVENT.
.LONG TERM...MONDAY NIGHT THROUGH FRIDAY
STILL NOT A LOT OF CONFIDENCE WITH THE FINER DETAILS WITHIN THE
EXTENDED...THOUGH TWO GENERAL TRENDS CAN BE EXPECTED. THE FIRST
WILL BE THE INFLUENCE OF A BROAD UPPER TROF AND EMBEDDED
SHORTWAVES MOVING ACROSS THE NORTHERN TIER CONUS. MOST OF THE
PRECIPITATION WILL BE ASSOCIATED WITH AN H7 LOW THAT LOOKS TO
TRACK ACROSS NORTH DAKOTA/MINNESOTA...THOUGH IT MAY PIVOT THROUGH
WESTERN SOUTH DAKOTA DEPENDING ON THE MODEL. THIS TRACK SUGGESTS
NORTH DAKOTA WILL RECEIVE THE MAJORITY OF PRECIPITATION WITHIN THE
WARM ADVECTION BAND AND ANY TROWAL BASED WRAP AROUND. THE GFS IS
GENERALLY WEAKER WITH SIGNIFICANTLY LOWER PRECIPITATION POTENTIAL.
THE ECMWF IS STRONGER...WITH A MORE SOUTHERLY TRACK...AND STRONGER
WINDS WITH POTENTIALLY MORE IMPACTS TO THE CWA.
THE SECOND FEATURE WILL BE ANOMALOUSLY COLD AIR POURING INTO THE
REGION. TIMING DIFFERENCES CONTINUE BETWEEN THE GFS AND
ECMWF...VARYING BETWEEN TUESDAY AND WEDNESDAY RESPECTIVELY. BOTH
MODELS RESOLVE THE COLD POOL WITH SIMILAR INTENSITY AND
DURATION...AS IT WILL COME TO DOMINATE THE WEATHER THROUGH THE END
OF THE WORK WEEK.
UNFORTUNATELY...BOTH MODELS HAVE BEEN REASONABLY CONSISTENT WITH
THEIR INDIVIDUAL TRENDS. WILL CONTINUE TO BROADBRUSH THE FIRST FEW
PERIODS OF THE EXTENDED WITH CHANCE POPS/SNOW UNTIL MODELS ENTER
BETTER ALIGNMENT.
&&
.AVIATION...
12Z TAFS FOR THE KABR...KATY...KPIR AND KMBG TERMINALS
VFR CONDITIONS EXPECTED AT ALL TERMINALS. LIGHT WINDS WILL BE OUT
OF THE NORTHWEST GRADUALLY SHIFTING TO THE NORTH.
&&
.ABR WATCHES/WARNINGS/ADVISORIES...
SD...NONE.
MN...NONE.
&&
$$
UPDATE...CONNELLY
SHORT TERM...SD
LONG TERM...CONNELLY
AVIATION...CONNELLY
WEATHER.GOV/ABERDEEN
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
404 PM CST SAT NOV 30 2013
.DISCUSSION...
252 PM CST
SYNOPSIS...MORE SEASONAL TEMPERATURES WILL BE WITH US THROUGH EARLY
NEXT WEEK...WITH TEMPS PEAKING MID WEEK. THEN TEMPS QUICKLY FALL
TO WELL BELOW NORMAL BY NEXT WEEKEND. THERE A FEW SLIGHT CHANCES OF
PRECIP EARLY NEXT WEEK WITH A MUCH BETTER CHANCE FOR PRECIP MID
WEEK. THE MID WEEK SYSTEM WILL BRING MOSTLY RAIN WITH A CHANCE OF
WINTRY PRECIP LATE NEXT WEEK.
REST OF TODAY THROUGH SUNDAY...
WEAK LOW PRESSURE IS OVER LAKE SUPERIOR AND NORTHERN WI WITH ITS
COLD FRONT STRETCHING FROM MEDFORD WI THROUGH MASON CITY IA. THE
LOW WILL CONTINUE EASTWARD AND DISSIPATE OVER THE EASTERN GREAT
LAKES SUNDAY NIGHT. WE HAVE MIXED MUCH MORE THAN WE WERE EXPECTING
TODAY...RESULTING IN HIGH TEMPS IN THE LOWER 50S. NOT BAD FOR LATE
NOVEMBER! AS SUCH RAISED LOW TEMPS BY A COUPLE DEGREES TONIGHT.
CLOUDS WILL ALSO BE INCREASING THIS EVENING AND OVERNIGHT LIMITING
COOLING.
AN UPPER LEVEL SHORTWAVE PASSES OVERHEAD TOMORROW MORNING WITH NO
PRECIP EXPECTED. CAA ALOFT AND WEAK SURFACE FLOW LEAD ME TO BELIEVE
WE WILL BE A BIT COOLER TOMORROW WITH HIGHS AROUND 40.
MONDAY AND TUESDAY...
ANOTHER SLIGHTLY DEEPER UPPER LEVEL SHORTWAVE ARRIVES MONDAY.
THIS TROUGH IS ALSO FURTHER SOUTH MOVING RIGHT OVER NORTHERN
IL...WHICH MAY PROVIDE JUST ENOUGH FORCING FOR A LITTLE LIGHT
PRECIP. TEMPS WILL BE ON THE RISE THROUGH THE MORNING SO WENT WITH
LIGHT SNOW AT FIRST TURNING OVER TO RAIN BY MONDAY AFTERNOON. THE
PRECIP WILL TRAVEL EAST WITH THE SHORTWAVE THROUGH THE DAY. HIGH
TEMPS ON MONDAY WILL ONCE AGAIN BE AROUND 40.
AN UPPER LEVEL VORT STREAMER PASSES JUST TO THE NORTH LATE MONDAY
NIGHT WHICH MAY PRODUCE A LITTLE LIGHT SNOW OVER NORTH CENTRAL IL.
MAY SEE A LITTLE MORE PRECIP COVERAGE TUESDAY MORNING WITH PRECIP
TURNING OVER TO RAIN AS TEMPS WARM. THE FORCING THEN LIFTS OFF TO
THE NE SO KEPT A SLIGHT CHANCE OF PRECIP OVER NORTH CENTRAL IL
TUESDAY AFTERNOON WITH THE MAJORITY OF PRECIP STAYING NORTH OF OUR
REGION CLOSER TO THE VORT STREAMER.
A STATIONARY FRONT THEN STRETCHES OVER NORTHERN IL TUESDAY NIGHT SO
KEPT A SLIGHT CHANCE TO CHANCE OF RAIN GOING. WAA ALOFT WILL KEEP
TUESDAY NIGHT TEMPS ABOVE FREEZING.
WEDNESDAY THROUGH FRIDAY...
THE UPPER LEVEL RIDGE SHIFTS TO THE EAST WITH SOUTHWEST FLOW SETTING
UP THROUGH LATE FRIDAY. THE UPPER LEVEL TROUGH AXIS PASSES OVERHEAD
SATURDAY. LONG DISTANCE GUIDANCE AGREES ON THE OVERALL
PATTERN...BUT THE GFS AND ECMWF DIFFER GREATLY ON WHEN THESE
FEATURES WILL IMPACT THE REGION. WENT WITH THE MORE STEADY ECMWF IN
THE LONG TERM AS THE GFS LOOKS MUCH TOO FAST.
A SURFACE LOW MOVES OVER THE CENTRAL PLAINS LATE TUESDAY NIGHT INTO
WEDNESDAY WITH WAA IMPACTING THE REGION TUESDAY NIGHT THROUGH
WEDNESDAY EVENING. WITH ALL OF THE WAA RAISED TEMPS TUESDAY NIGHT
AND WEDNESDAY...AND HONESTLY...STILL THINK TEMPS ARE TOO LOW. COULD
EASILY SEE AT LEAST LOW 50S ON WEDNESDAY.
RAIN ARRIVES BEHIND THE WARM FRONT WEDNESDAY AFTERNOON WITH GUIDANCE
BACKING OFF A LITTLE WITH QPF...TO AROUND 0.1 INCHES. THE LOWS COLD
FRONT SWINGS THROUGH WED NIGHT/THURSDAY WITH TEMPS CRASHING BEHIND
IT. COULD EASILY SEE A 10+ DEGREE DIFFERENCE IN HIGH TEMPS WEDNESDAY
AND THURSDAY. PRECIP MAY LINGER A BIT BEHIND THE COLD
FRONT...MEANING WINTRY PRECIP IS POSSIBLE. GUIDANCE INDICATES
PRECIP WILL ALSO FORM AHEAD OF THE UPPER LEVEL TROUGH
AXIS...RESULTING IN RAIN/SNOW THURSDAY BECOMING ALL SNOW THURSDAY
NIGHT THROUGH LATE FRIDAY.
ARCTIC AIR MOVES IN WITH THE TROUGH AXIS RESULTING IN HIGH TEMPS IN
THE 20S LATE NEXT WEEK. MAY EVEN SEE HIGH TEMPS IN THE TEENS ON
SATURDAY.
CONFIDENCE IS HIGH THAT THE SYSTEM WILL IMPACT THE REGION MID NEXT
WEEK...PRECIP WILL BE MOSTLY RAIN...AND IN TEMP TRENDS. MEDIUM
CONFIDENCE IN HOW LONG PRECIP WILL LINGER.
JEE
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 22Z...
* MVFR CIGS POSSIBLE SUNDAY MORNING
IZZI
//DISCUSSION...UPDATED 18Z...
HIGH PRESSURE WAS OVER NEW ENGLAND AND WEAK LOW PRESSURE WAS OVER
LAKE SUPERIOR AT MIDDAY...WITH A COLD FRONT TRAILING THROUGH
NORTHWEST WISCONSIN AND IOWA. SOUTHWEST FLOW AHEAD OF THE FRONT
WAS BRINGING MILD DRY AIR TO THE REGION. A FAIRLY SHALLOW
INVERSION IS IN PLACE BUT WITH FULL SUN THERE IS ENOUGH MIXING FOR
A FEW GUSTS IN THE MID TO UPPER TEENS THIS AFTERNOON. LATE THIS
AFTERNOON WITH LOSS OF HEATING AND MIXING...WINDS AND GUSTS WILL
DIMINISH. WINDS WILL GRADUALLY VEER FROM SSW TO SW TO WSW THROUGH
THE EVENING HOURS AS THE FRONT APPROACHES. WINDS WILL BE LIGHT AS
THE WEAK FRONT SLIPS THROUGH THE AREA. NEW SHORT RANGE MODELS ALL
VERY SIMILAR IN TIMING OF THE FRONTAL PASSAGE THROUGH THE
TERMINALS. WINDS WILL QUICKLY SHIFT TO NW BEHIND THE FRONT...THEN
GRADUALLY CONTINUE TO COME AROUND TO NNE DURING THE DAY SUNDAY.
MAIN CONCERN IS FOR THE POTENTIAL OF MVFR CIG AND SOME LIGHT FOG
AND HAZE IN THE EARLY MORNING BEHIND THE FRONT. NAM AND LOCAL ARW
MOST AGGRESSIVE IN MOISTENING LOWEST PART OF SOUNDING. THIS WOULD
SUGGEST CIGS AT OR BELOW 1000 FT WITH SOME FOG AND HAZE. GFS KEEPS
INVERSION AROUND 2500 FT. TIMING OF STRATUS COULD BE DELAYED A FEW
HOURS AFTER FROPA. FOR NOW WILL CONTINUE TREND OF PREVIOUS
FORECAST WITH CIGS AROUND 2K FT AFTER FROPA.
ALLSOPP
//ORD AND MDW CONFIDENCE...UPDATED 22Z...
* HIGH CONFIDENCE IN WIND FORECAST
* HIGH CONFIDENCE IN VFR CONDITIONS THROUGH TONIGHT
* LOW/MEDIUM CONFIDENCE ON MVFR CIGS SUNDAY MORNING
IZZI
//OUTLOOK FOR ORD/MDW FOR 00Z MONDAY-12Z SATURDAY...UPDATED 12Z...
SUNDAY NIGHT...VFR...THOUGH MVFR CIGS POSSIBLE.
MONDAY INTO TUESDAY...MVFR CIGS POSSIBLE. SLIGHT CHANCE -RASN.
WEDNESDAY...MVFR CIGS PROBABLE CHANCE OF IFR. CHANCE OF RAIN.
THURSDAY...MVFR CIGS PROBABLE. CHANCE -RASN.
FRIDAY...VFR.
RATZER
&&
.MARINE...
252 PM CST
WINDS WILL TURN NORTH TONIGHT THROUGH THE OVERNIGHT BEHIND A COLD
FRONT...BUT WILL BE LIGHTER AT 20 KT OR LESS DUE TO A WEAK PRESSURE
GRADIENT. THE GENERALLY LIGHT WIND REGIME WILL CONTINUE SUNDAY INTO
TUESDAY MORNING WITH WINDS GRADUALLY SHIFTING FROM NORTHEAST TO
SOUTHEAST. UNCERTAINTY THEN INCREASES AMONGST MEDIUM RANGE GUIDANCE
WITH TRACK AND TIMING OF LOW PRESSURE SYSTEM MOVING EAST FROM THE
PLAINS. WITH THIS FORECAST PACKAGE HAVE FAVORED A SLOWER TIMING OF
THIS SYSTEM...WHICH WILL RESULT IN INCREASINGLY STRONG SOUTHEAST TO
SOUTH WINDS TUESDAY NIGHT THROUGH WEDNESDAY NIGHT. A COLD FRONT IS
THEN EXPECTED TO SWEEP ACROSS THE LAKE ON THURSDAY AS THE LOW TRACKS
TO OR NORTH OF LAKE SUPERIOR BY THURSDAY. THIS WILL RESULT IN
STRONGER SOUTHWEST TO WESTERLY WINDS. THE POTENTIAL EXISTS FOR A
PERIOD OR TWO OF GALES IN ASSOCIATION WITH THIS SYSTEM...BUT DUE TO
THE UNCERTAINTY...THERE ARE NO GALES IN THE FORECAST YET. THE ACTIVE
PATTERN OVER THE LAKE THEN LOOKS TO CONTINUE INTO NEXT WEEKEND.
RC
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...NONE.
&&
$$
VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE)
FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
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[top]
Area Forecast Discussion
National Weather Service Lincoln IL
336 PM CST Sat Nov 30 2013
.DISCUSSION...
ISSUED 335 PM CST Sat Nov 30 2013
A relatively mild weather pattern will start out the first few
days of December, before our next best chance of precipitation and
much colder air moves in for the latter part of the week. The
short range models are in fair agreement into the first part of
next week. However, the medium range solutions diverge
significantly by mid-week which has pretty big implications on the
forecast.
SHORT TERM...Tonight through Monday
A weak cold front from western WI across southern MN and South
Dakota is expected to approach central IL Sunday morning. Ahead of
this front, a light wind and dew points mainly in the lower 30s
could result in some light fog and few low clouds late tonight and
early Sunday morning. The NAM model is hitting this harder than
the others, which it has been doing more so lately and seems to
have this tendency in the cool season. Will go with partly cloudy
conditions for now and monitor this evening.
Mild conditions are expected on Sunday, with readings of 45 to 50
in central IL and the lower 50s south of I-70. The forecast gets a
bit tricky for Sunday night into Monday as a shortwave in the WNW
flow approaches the state. Many of the short range model solutions
are depicting the potential for light rain as early as late Sunday
night and during the day Monday. Will hold off on any mention for
Sunday night into early Monday morning because of a fairly thick
layer of dry air expected between 850-925 mb. Will stick with the
slight chance for rain during the day Monday as a bit stronger
lift could produce isolated pockets of light rain.
LONG TERM...Tuesday through Saturday
There are quiet significant model differences between the GFS,
Canadian and European solutions starting Tuesday, which continues
right through the rest of the forecast period. The GFS is much
quicker with shifting an upper level low from the Pacific NW
across the northern states. However, while it is doing this, it is
also digging a portion of the upper level energy toward the
southwestern U.S. This should result in upper level ridging in the
Midwest, which would force any northern energy up into central
Canada. The GFS does not do this though, which results in a cold
front moving through late Tuesday/early Wednesday. The European
and Canadian model solutions make much more sense by holding off
on the frontal passage at least 24-36 hours later, on early
Thursday.
Several shortwaves moving up from the southwest, and a slowing
front expected to become parallel to the flow aloft will mean
periods of precipitation from Wednesday through much of Friday.
Rain will be the primary precipitation type at onset on Wednesday,
but then as colder air gradually advects toward the region, a
mixture changing to snow is anticipated - primarily later in the
day Thursday, and especially Friday. The best low level moisture
and forcing is expected to the east and south of our region -
closer to the frontal position - near the Ohio Valley. Thus, at
this time we are not anticipating any major snow amounts, but with
the complex evolution of this system and the fact that it is six days
away, the confidence factor is not very high either way.
Miller
&&
.AVIATION...
ISSUED 1105 AM CST Sat Nov 30 2013
High pressure sliding to the east giving way to increasing RH in
the region resulting in a troublesome forecast for the overnight
hours in ILX terminals. NAM has far more moisture trapped in the
boundary layer and guidance resulting in everything from MVFR vis
to LIFR cigs and vis. GFS in the same shape with less moisture and
the HRRR is a little slower and more conservative but still
moisture laden particularly NW of the Illinois River Valley.
Trouble is, lower res models have increased moisture already in
central MO, and sat imagery pointing to an overdone model run.
That being said, dewpoints are on the increase with swrly flow.
HRRR depiction of sfc RH a little more on track and def
highlighting overnight NW of the IL river. Trouble is whether or
not we are looking at stratus developing or vis drop. Not to
mention that if enough moisture makes it into the SE and does not
mix out this afternoon, chance for reduced vis in the SE as the
skies clear out a bit tonight. For now, forecast conservative, but
starting the trend for a visibility drop with majority rule to a
cloud deck in the 4000 to 5000 ft range for PIA BMI and SPI this
evening and through the overnight.
HJS
&&
.ILX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
1152 AM CST SAT NOV 30 2013
.DISCUSSION...
1051 AM CST
MORNING UPDATE...
MIXING HEIGHTS ARE FAIRLY SHALLOW TODAY...BUT SOUTH-SOUTHWEST WARM
ADVECTION PATTERN AND FULL SUNSHINE ARE RESULTING IN A MUCH MORE
PLEASANT DAY THAN WE HAVE SEEN OF LATE. TEMPERATURES WERE
INITIALLY SLOW TO RISE THIS MORNING...BUT SINCE HAVE BEEN QUICKLY
WARMING. BASED ON TRENDS AND EXPECTATIONS OF CONTINUED STEADY
WARMING UNTIL ABOUT 3PM...HAVE BUMPED UP HIGH TEMPERATURES TO THE
MID AND UPPER 40S NORTH OF I-80 AND UPPER 40S TO LOCALLY AROUND 50
SOUTH OF I-80. WILL CONTINUE TO MONITOR TEMPERATURE TRENDS...AS
SOME SHORT RANGE GUIDANCE INDICATES THE POTENTIAL TO WARM EVEN A
BIT MORE THAN THIS.
RC
//PREV DISCUSSION...
248 AM CST
PRIMARY FORECAST CHALLENGE WILL BE PINNING DOWN BEST CHANCES FOR
PRECIP AS PATTERN BECOMES ACTIVE NEXT WEEK...
THIS WEEKEND...
QUIET WEATHER SHOULD PREVAIL LOCALLY AS DEPARTING HIGH PRESSURE
ALLOWS RETURN FLOW INTO THE UPPER MIDWEST TO HELP MODERATE
TEMPERATURES THIS AFTERNOON. GUIDANCE IN PRETTY GOOD AGREEMENT
INDICATING LOW TO MID 40S ACROSS THE CWA TODAY. BLENDED TOWARDS NAM
WHICH HAS A DECENT ALBEIT TOO FAR SOUTH AND TOO BROAD A HANDLE ON
THE SNOWFALL CURRENTLY ON THE GROUND ACROSS THE FAR NORTHERN
CWA...BUT INDICATES THOSE AREAS WILL NOT GET OUT OF THE UPPER 30S
THIS AFTERNOON.
A CLIPPER SYSTEM WILL BRING SNOW TO THE NORTHERN LAKES REGION THIS
WEEKEND...BUT A TRAILING COLD FRONT WHICH WILL PASS OVER THE LOCAL
AREA TONIGHT AND EARLY SUNDAY WILL BE MOISTURE STARVED AND LIKELY
NOT PRODUCE ANY PRECIPITATION. THE CAVEAT...NAM GUIDANCE IN
PARTICULAR CONTINUES TO INDICATE A SHALLOW POST FRONTAL STRATUS DECK
WITH WEAK HEIGHT FALLS AS A SHEARED UPPER WAVE PUSHES ACROSS THE
AREA...WHICH MAY CULMINATE IN LIGHT FREEZING DRIZZLE. BUT GIVEN THE
NAMS LOW LEVEL MOISTURE BIAS AND THE GFS BACKING OFF ON A STRONGER
UPPER WAVE THAT PREVIOUS RUNS WERE ADVERTISING...WILL CONTINUE TO
MAINTAIN A DRY FORECAST.
MONDAY AND TUESDAY...
STRONG UPPER LOW DIGGING ACROSS THE PAC NW THIS PERIOD WILL RESULT
IN DOWNSTREAM AMPLIFICATION OF LONGWAVE RIDGE AS STRONG WARM
ADVECTION DEVELOPS ACROSS THE MID/UPPER MISSISSIPPI VALLEY. MID LEVEL
THERMAL RIBBON WILL SET UP FROM THE DAKOTAS SOUTHEAST INTO THE MID
MISSISSIPPI VALLEY WITH ISENTROPIC ASCENT RESULTING IN PRECIPITATION
WHICH APPEARS WILL BE FOCUSED JUST TO OUR WEST MONDAY...THOUGH
GUIDANCE CONTINUES TO STRUGGLE LOCKING ONTO DETAILS. THERE MAY BE A
SUBTLE WAVE THAT MOVES ACROSS THE AREA...WHICH ECMWF AND NAM SUGGEST
WILL BRING LIGHT PRECIP TO THE AREA EARLY MONDAY. PRETTY DRY
MIDLEVEL AIRMASS THOUGH MAY BE INSURMOUNTABLE...SO CAPPED POPS AT
SLIGHT CHC MONDAY. THERMAL RIDGE WILL GRADUALLY TRANSLATE ENE MONDAY
NIGHT AND SHOULD EVENTUALLY SPREAD ACROSS THE CWA. MOISTURE
AVAILABILITY STILL A BIG QUESTION MARK WITH RESPECT TO TIMING THE
ONSET OF PRECIPITATION...BUT MORE PERSISTENT FORCING SHOULD
EVENTUALLY SATURATE THE COLUMN. PRECIP SHOULD START AS SNOW...OR
POSSIBLY RAIN SNOW MIX BEFORE TRANSITIONING TO ALL RAIN TUESDAY AS
WE CONTINUE TO WARM THE COLUMN.
WEDNESDAY AND THURSDAY...
ELONGATED SURFACE LOW IS PROGGED TO LIFT NORTHEAST ACROSS THE UPPER
MIDWEST INTO THE NORTHERN LAKES REGION WEDNESDAY INTO THURSDAY. AS
THE WARM FRONT LIFTS NORTH ACROSS THE AREA...CONTINUE TO FEEL THAT
50S MAY OVERSPREAD AT LEAST THE SOUTHERN HALF OF THE CWA IF NOT INTO
THE CHICAGO METRO AREA WEDNESDAY AFTERNOON...DESPITE CLOUD COVER AND
PRECIP CHANCES. LATEST EMCWF TAKES THE 50 ISOTHERM ALL THE WAY TO
THE STATE LINE...AND OFTEN IS ONE OF THE BETTER PERFORMING MODELS
UNDER A THERMAL RIDGE. REMAIN CONSERVATIVE BRINGING THE WARMTH
NORTHWARD...BUT DID TREND TEMPERATURES UP A COUPLE DEGREES FROM
GOING FORECAST.
THERE CONTINUES TO BE CONSIDERABLE SPREAD IN MODEL SOLUTIONS
RESULTING IN LOW CONFIDENCE PARTICULARLY WITH TIMING PRECIP...THOUGH
CONFIDENCE IN WIDESPREAD PRECIP OVERSPREADING THE AREA AT SOME POINT
IS FAIRLY HIGH AS THE WARM CONVEYOR BELT TRANSLATES EAST ACROSS THE
REGION WEDNESDAY/WEDNESDAY NIGHT. A COLD FRONT WILL THEN SWEEP
ACROSS THE AREA LATE WEDNESDAY NIGHT INTO THURSDAY WITH PRECIP
CHANGING OVER TO SNOW BRIEFLY BEFORE ENDING. AT THIS POINT DO NOT
ANTICIPATE ANY ACCUMULATIONS WITH THE BULK OF THE PRECIP LIQUID.
LEANED HEAVILY ON BLEND OF EMCWF AND GEM GUIDANCE FOR TIMING POPS
WHICH WERE BETTER CLUSTERED COMPARED TO THE MUCH FASTER GFS.
DEUBELBEISS
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 18Z...
* WEAK COLD FRONT WILL TURN WINDS FROM SW TO NNW LATE TONIGHT.
* MVFR CIG WILL LIKELY DEVELOP BEHIND COLD FRONT SUNDAY MORNING
AND PERSIST THROUGH THE DAY SUNDAY.
ALLSOPP
//DISCUSSION...UPDATED 18Z...
HIGH PRESSURE WAS OVER NEW ENGLAND AND WEAK LOW PRESSURE WAS OVER
LAKE SUPERIOR AT MIDDAY...WITH A COLD FRONT TRAILING THROUGH
NORTHWEST WISCONSIN AND IOWA. SOUTHWEST FLOW AHEAD OF THE FRONT
WAS BRINGING MILD DRY AIR TO THE REGION. A FAIRLY SHALLOW
INVERSION IS IN PLACE BUT WITH FULL SUN THERE IS ENOUGH MIXING FOR
A FEW GUSTS IN THE MID TO UPPER TEENS THIS AFTERNOON. LATE THIS
AFTERNOON WITH LOSS OF HEATING AND MIXING...WINDS AND GUSTS WILL
DIMINISH. WINDS WILL GRADUALLY VEER FROM SSW TO SW TO WSW THROUGH
THE EVENING HOURS AS THE FRONT APPROACHES. WINDS WILL BE LIGHT AS
THE WEAK FRONT SLIPS THROUGH THE AREA. NEW SHORT RANGE MODELS ALL
VERY SIMILAR IN TIMING OF THE FRONTAL PASSAGE THROUGH THE
TERMINALS. WINDS WILL QUICKLY SHIFT TO NW BEHIND THE FRONT...THEN
GRADUALLY CONTINUE TO COME AROUND TO NNE DURING THE DAY SUNDAY.
MAIN CONCERN IS FOR THE POTENTIAL OF MVFR CIG AND SOME LIGHT FOG
AND HAZE IN THE EARLY MORNING BEHIND THE FRONT. NAM AND LOCAL ARW
MOST AGGRESSIVE IN MOISTENING LOWEST PART OF SOUNDING. THIS WOULD
SUGGEST CIGS AT OR BELOW 1000 FT WITH SOME FOG AND HAZE. GFS KEEPS
INVERSION AROUND 2500 FT. TIMING OF STRATUS COULD BE DELAYED A FEW
HOURS AFTER FROPA. FOR NOW WILL CONTINUE TREND OF PREVIOUS
FORECAST WITH CIGS AROUND 2K FT AFTER FROPA.
ALLSOPP
//ORD AND MDW CONFIDENCE...UPDATED 18Z...
* HIGH CONFIDENCE IN WIND FORECAST.
* MEDIUM TO HIGH CONFIDENCE IN MVFR CIG DEVELOPING BUT LOW
CONFIDENCE IN TIMING AND HEIGHT OF CIG.
ALLSOPP
//OUTLOOK FOR ORD/MDW FOR 00Z MONDAY-12Z SATURDAY...UPDATED 12Z...
SUNDAY NIGHT...VFR...THOUGH MVFR CIGS POSSIBLE.
MONDAY INTO TUESDAY...MVFR CIGS POSSIBLE. SLIGHT CHANCE -RASN.
WEDNESDAY...MVFR CIGS PROBABLE CHANCE OF IFR. CHANCE OF RAIN.
THURSDAY...MVFR CIGS PROBABLE. CHANCE -RASN.
FRIDAY...VFR.
RATZER
&&
.MARINE...
302 AM CST
MAIN MARINE FORECAST CONCERNS ARE STRONG SOUTH WINDS AND GALES ON
THE NORTHERN PART OF THE LAKE THIS MORNING...AND TIMING OF A STRONG
LOW PRESSURE SYSTEM EXPECTED TO AFFECT THE WESTERN GREAT LAKES
REGION TOWARD THE MIDDLE OF NEXT WEEK.
STRONG HIGH PRESSURE WAS OVER NEW ENGLAND THIS MORNING...AND WILL
MOVE SLOWLY EAST OFF OF THE ATLANTIC COAST TODAY. LOW PRESSURE OVER
THE DAKOTAS WILL TRACK EAST ACROSS LAKE SUPERIOR TODAY...THEN
SOUTHEAST ACROSS THE EASTERN LAKES TONIGHT. IN THE PROCESS...A COLD
FRONT TRAILING FROM THIS LOW WILL MOVE SOUTHEAST ACROSS LAKE
MICHIGAN LATE THIS AFTERNOON AND TONIGHT. WITH THE STRONG HIGH TO
THE EAST AND THE LOW PASSING TO THE NORTH...THE SURFACE PRESSURE
GRADIENT HAS TIGHTENED AND WAS PRODUCING SOUTH WINDS 30-35 KT ACROSS
THE NORTHERN PART OF THE LAKE...AND NEAR 30 KT SOUTH. THIS WILL
CONTINUE THROUGH THE MID-MORNING HOURS TODAY...BEFORE THE GRADIENT
WEAKENS WITH THE APPROACH OF THE LOW AND COLD FRONTAL TROUGH. THIS
WILL ALLOW WINDS TO DIMINISH...EVENTUALLY VEERING TO THE NORTH
BEHIND THE COLD FRONT AND THEN BECOMING NORTH-NORTHEAST ON SUNDAY.
HIGH PRESSURE WILL THEN SPREAD EAST ACROSS ONTARIO AND QUEBEC SUNDAY
INTO MONDAY...WITH WEAKER RIDGING EXTENDING ACROSS THE WESTERN
LAKES. A LARGE AREA OF LOW PRESSURE IS EXPECTED TO DEVELOP OVER THE
NORTHERN HIGH PLAINS MONDAY...DEEPENING AND SLOWLY MOVING EAST
TOWARD THE LAKES THROUGH MID-WEEK. MODEST EAST-NORTHEAST WINDS NEAR
THE SURFACE HIGH PRESSURE RIDGE WILL EVENTUALLY BECOME MORE
EAST-SOUTHEAST AND INCREASE AS THE LOW APPROACHES TUESDAY NIGHT AND
WEDNESDAY.
FOR THE ILLINOIS AND INDIANA NEAR SHORE WATERS...SOUTH WINDS GUSTING
20-25 KT THIS MORNING ARE LIKELY PRODUCING WAVES OF 4+ FT NORTH
OF DOWNTOWN CHICAGO. THEREFORE HAVE ISSUED A SMALL CRAFT ADVISORY
FOR THAT PART OF THE IL SHORE THROUGH MID-MORNING. WINDS BECOMING
SOUTHWEST WILL ALLOW WAVES TO SUBSIDE BELOW SMALL CRAFT ADVISORY
CRITERIA AFTER THAT TIME.
RATZER
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...NONE.
&&
$$
VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE)
FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
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WWW.TWITTER.COM/NWSCHICAGO
WWW.YOUTUBE.COM/NWSCHICAGO
Area Forecast Discussion
National Weather Service Lincoln IL
1149 AM CST Sat Nov 30 2013
.DISCUSSION...
ISSUED 1057 AM CST Sat Nov 30 2013
High pressure sliding to the east this morning and southerly flow
setting up over Central Illinois. Temperatures are warming up
faster than the diurnal trend and have boosted highs a degree or
two as well as adjusted the hourlys and the sky grids for more
sunshine. Overall subtle adjustments, but will send out an update
to cover the few changes.
&&
.AVIATION...
ISSUED 1105 AM CST Sat Nov 30 2013
High pressure sliding to the east giving way to increasing RH in
the region resulting in a troublesome forecast for the overnight
hours in ILX terminals. NAM has far more moisture trapped in the
boundary layer and guidance resulting in everything from MVFR vis
to LIFR cigs and vis. GFS in the same shape with less moisture and
the HRRR is a little slower and more conservative but still
moisture laden particularly NW of the Illinois River Valley.
Trouble is, lower res models have increased moisture already in
central MO, and sat imagery pointing to an overdone model run.
That being said, dewpoints are on the increase with swrly flow.
HRRR depiction of sfc RH a little more on track and def
highlighting overnight NW of the IL river. Trouble is whether or
not we are looking at stratus developing or vis drop. Not to
mention that if enough moisture makes it into the SE and does not
mix out this afternoon, chance for reduced vis in the SE as the
skies clear out a bit tonight. For now, forecast conservative, but
starting the trend for a visibility drop with majority rule to a
cloud deck in the 4000 to 5000 ft range for PIA BMI and SPI this
evening and through the overnight.
HJS
&&
.PREV DISCUSSION...
ISSUED 227 AM CST Sat Nov 30 2013
Main forecast challenge focuses on departing storm system for the
middle and end of next week...and whether or not it will produce
any wintry precipitation across central Illinois.
SHORT TERM...Today through Monday
Mild and quiet weather will prevail through the short-term.
Increasing southerly winds on the back-side of high pressure
anchored along the East Coast will bring above normal temperatures
back into the area today. Despite a chilly start to the day, the
southerly flow coupled with ample afternoon sunshine will boost
highs into the middle to upper 40s, with a few locations across
the S/SW KILX CWA potentially reaching the 50 degree mark. A weak
cold front will sag southward into the area on Sunday, bringing a
few clouds and a shift in the winds. Thanks to northerly winds
behind the boundary across the northern half of the CWA,
temperatures will be a couple of degrees cooler than today.
Front will become parallel to the zonal upper-level flow and will
stall across the Ohio River Valley Sunday night into Monday. As
Gulf moisture continues to flow northward over the boundary and a
short-wave trough ripples eastward out of the Plains, a few light
rain showers may develop on Monday. Several of the operational
models are hinting at this, so have included a 20 POP accordingly.
LONG TERM...Tuesday through Friday
Main show will hold off until the extended, as an upper-level low
currently over Alaska sinks southward and carves out a long-wave
trough across the western CONUS by the middle of the week.
Downstream ridging will produce deep southwesterly flow over the
Midwest, resulting in cloudy skies and increasing precip chances
Wednesday into Thursday. Model spread is still significant, so
exact evolution of the developing storm system is uncertain at
this time. General consensus develops surface low pressure in the
lee of the Rockies, then tracks it northeastward into Canada by
Thursday. Trailing cold front will likely push through Illinois
Wednesday night into Thursday, triggering scattered showers and
perhaps a thunderstorm. Things get tricky once the front passes
and the colder air begins to arrive Thursday into Friday. 00z Nov
30 GFS/GEM both show front quickly advancing eastward, with precip
largely ending before the cold airmass spreads into the area. This
would tend to support a brief change-over to light snow Thursday
night as the front slides eastward into Indiana before the precip
comes to an end on Friday. Meanwhile, the 00z ECMWF suggests much
more precip will hang back in the cold air Thursday night,
followed by another wave of low pressure riding along the boundary
and a renewed round of precip in the cold airmass on Friday. This
could lead to a much more wintry scenario, with rain changing to
snow Thursday night and another chance for snow on Friday. At this
point, will trend toward the GFS/GEM consensus. As a result, will
mention a rain/snow mix west of the Illinois River as early as
Thursday, with rain changing to light snow further east to the
Indiana border Thursday night. Will go with a mainly dry forecast
for Friday, but will hold on to a chance for rain/snow across the
far E/SE CWA in case secondary wave does indeed develop along
departing front. Once this system exits the region, much colder
weather will be on tap for the end of the week.
&&
.ILX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS INDIANAPOLIS IN
228 PM EST SAT NOV 30 2013
.UPDATE...
THE LONG TERM SECTION HAS BEEN UPDATED BELOW.
&&
.SYNOPSIS...
ISSUED AT 328 AM EST SAT NOV 30 2013
AFTER A MAINLY SUNNY DAY...CLOUDS WILL INCREASE ACROSS THE OHIO
VALLEY FOR THE SECOND HALF OF THE WEEKEND INTO EARLY NEXT WEEK AS A
WEAK FRONT SLIDES INTO THE REGION. A FEW LIGHT RAIN SHOWERS OR
SPRINKLES WILL BE POSSIBLE FROM SUNDAY AFTERNOON THROUGH MONDAY AS A
COUPLE OF WEAK WAVE ALOFT MOVE ACROSS THE OHIO VALLEY. A MUCH BETTER
CHANCE FOR RAIN WILL COME FOR THE SECOND HALF OF THE WEEK AS A
STRONG COLD FRONT TRACKS THROUGH THE REGION. COLDER AIR WILL ONCE
AGAIN RETURN BY THE END OF THE WEEK.
&&
.NEAR TERM /REST OF TODAY/...
ISSUED AT 954 AM EST SAT NOV 30 2013
UPDATE...
SOME MID/HIGH CLOUDS WERE STILL ACROSS OUR FAR EAST...BUT HAVE
CLEARED OUT ELSEWHERE. UPSTREAM SKIES WERE CLEAR AND WILL SCALE
BACK CLOUD COVER A LITTLE WITH MOST AREAS BEING SUNNY THIS
AFTERNOON.
ONLY OTHER CHANGE WAS TO TWEAK TEMPERATURES UP A DEGREE SOME AREAS
BASED ON 12Z RUC 2 METER TEMPERATURES...LOTS OF SUNSHINE AND WARM
ADVECTION. ALL IN ALL THE CURRENT FORECAST IS ON TRACK.
PREVIOUS NEAR TERM DISCUSSION FOLLOWS...
MID AND HIGH LEVEL CLOUD COVER DRAPED ACROSS MUCH OF THE OHIO VALLEY
EARLY THIS MORNING AS A WEAK WAVE ALOFT TRACKS ACROSS THE AREA.
TEMPS WERE MAINLY IN THE 20S AT 08Z.
BACK EDGE OF THE MORE SUBSTANTIAL HIGHER CLOUDS IS ALREADY EAST OF
THE MISSISSIPPI RIVER EARLY THIS MORNING. EXPECT CLOUDS TO DIMINISH
FROM WEST TO EAST ACROSS THE FORECAST AREA AROUND OR SHORTLY AFTER
DAYBREAK...WITH SKIES THEN BECOMING MOSTLY SUNNY WITH ONLY PATCHY
CIRRUS FOR THE REST OF THE DAY.
WITH THE BROAD HIGH PRESSURE RIDGE NOW LOCATED EAST OF THE
REGION...RETURN SOUTHERLY FLOW WILL DEVELOP AND INCREASE BY THIS
AFTERNOON AS BOUNDARY LAYER FLOW STRENGTHENS AHEAD OF AN APPROACHING
COLD FRONT. MODEL SOUNDINGS SUPPORT MAX GUSTS TO 20-25MPH BY THE
AFTERNOON AS LOW LEVEL MIXING INCREASES. GUSTS WILL DROP OFF NEAR
SUNSET AS THE NOCTURNAL INVERSION ESTABLISHES.
TEMPS...SOUTHERLY FLOW AND WARM ADVECTION WILL BRING WARMER TEMPS
INTO CENTRAL INDIANA FOR TODAY. MOS GUIDANCE MATCHES UP NICELY WITH
LOW LEVEL THERMALS...WITH HIGHS TOPPING OUT NEAR LATE NOVEMBER
NORMALS IN THE MID/UPPER 40S.
&&
.SHORT TERM /TONIGHT THROUGH MONDAY NIGHT/...
ISSUED AT 328 AM EST SAT NOV 30 2013
FORECAST CHALLENGES FOCUS ON POTENTIAL FOR LIGHT PRECIP AS THE
AFOREMENTIONED COLD FRONT DROPS INTO THE REGION...STALLS AND
EVENTUALLY WASHES OUT.
PREDOMINANT ZONAL FLOW IN THE UPPER LEVELS WILL BE PRESENT THROUGH
THE PERIOD WITH SEVERAL WEAK WAVES ALOFT TRACKING QUICKLY THROUGH
THE OHIO VALLEY. AT THE SURFACE...THE COLD FRONT WILL SLIDE SLOWLY
SOUTH INTO THE REGION ON SUNDAY...EVENTUALLY STALLING OUT OVER
SOUTHERN INDIANA SUNDAY NIGHT BEFORE WASHING OUT MONDAY. MOISTURE
ACCOMPANYING THE FRONT WILL BE LIMITED...BUT MODEL SOUNDINGS AND RH
PROGS CONTINUE TO SHOW IT IN GREATEST ABUNDANCE IN THE UPPER
PORTIONS OF THE BOUNDARY LAYER BEGINNING EARLY SUNDAY...GRADUALLY
LOWERING TO AROUND 2-3KFT INTO MONDAY AS AN INVERSION STEADILY
STRENGTHENS.
EXPECT CLOUDS TO EXPAND SOUTHEAST INTO THE FORECAST AREA AHEAD OF
THE FRONT BEGINNING LATE TONIGHT AND CONTINUING INTO SUNDAY. WEAK
ISENTROPIC LIFT AND A SUBTLE WAVE ALOFT MAY BE JUST ENOUGH TO
GENERATE SOME LIGHT PRECIP SUNDAY AFTERNOON AND NIGHT...LIKELY IN
THE FORM OF SPRINKLES...DRIZZLE OR VERY LIGHT RAIN SHOWERS. LOW
LEVELS AND SURFACE TEMPS SHOULD REMAIN WARM ENOUGH TO SUPPORT PRECIP
TYPE AS RAIN ONLY SUNDAY NIGHT. MODEL GUIDANCE LARGELY IN AGREEMENT
ON BRINGING A SLIGHTLY STRONGER...BETTER PHASED UPPER WAVE ACROSS
THE OHIO VALLEY ON MONDAY. WITH LOW LEVEL MOISTURE IN ABUNDANCE...
THIS FEATURE SHOULD PRESENT A BETTER OPPORTUNITY FOR A FEW LIGHT
RAIN SHOWERS. WILL CARRY JUST LOW CHANCE POPS HOWEVER AS ISENTROPIC
LIFT REMAINS WEAK. MAJORITY OF THE MODEL GUIDANCE FAVORING THE
PASSAGE OF THIS UPPER WAVE BY MONDAY EVENING...AND WILL END PRECIP
CHANCES AS RIDGING ALOFT EXPANDS INTO THE OHIO VALLEY BY EARLY
TUESDAY.
TEMPS...CONSIDERING THE INCREASING CLOUDS AND POTENTIAL FOR WEAK
COLD ADVECTION TO DEVELOP ON SUNDAY...METMOS TEMPS IN THE UPPER
40S/LOWER 50S LOOK RATHER AGGRESSIVE. HAVE TRENDED CLOSER TO /BUT
NOT AS COLD AS/ THE MAVMOS FOR SUNDAY HIGHS. LEANED TOWARDS THE
MAVMOS AGAIN FOR MONDAY WITH LIGHT RAIN/CLOUDS PRESENT. NEAR MAVMOS
FOR LOWS TONIGHT...THEN TRENDED TOWARDS THE WARMER METMOS FOR SUNDAY
NIGHT WITH EXPECTED CLOUD COVER.
&&
.LONG TERM /TUESDAY NIGHT THROUGH SATURDAY/...
ISSUED AT 228 PM EST SAT NOV 30 2013
MODELS ARE CLOSE ENOUGH FOR THE MOST PART INTO THURSDAY...BUT DIFFER
IN PRECIPITATION SIGNIFICANTLY ON FRIDAY. UNCERTAINTY IS HIGH SO
GENERALLY STUCK CLOSE TO THE ALLBLEND INITIALIZATION FOR MOST ITEMS.
THERE IS SOME UNCERTAINTY ON LIGHT RAIN DEVELOPMENT IN THE WARM
ADVECTION PATTERN AHEAD OF THE ARCTIC FRONT TUESDAY NIGHT INTO
WEDNESDAY. WITH ONLY LOW CHANCES FOR RAIN DECIDED TO KEEP CONTINUITY
WITH PREVIOUS FORECAST AND GO DRY TUESDAY NIGHT AND SLIGHT CHANCE
POPS FOR WEDNESDAY.
CHANCES FOR RAIN THEN INCREASE INTO THURSDAY WITH LIKELY POPS
THURSDAY AND THURSDAY NIGHT. ARCTIC FRONT SHOULD HAVE PLENTY OF
MOISTURE TO WORK WITH DURING THIS PERIOD.
QUESTIONS THEN ARISE FOR POPS ON FRIDAY. 00Z AND 12Z ECMWF KEEP
PRECIPITATION ACROSS THE AREA AS A WAVE RIDES ALONG THE FRONT. GFS
KEEPS WAVE FARTHER SOUTHEAST SO OUR AREA REMAINS DRY. SOME GFS
ENSEMBLES ARE CLOSER TO THE ECMWF SOLUTION. 12Z CANADIAN WOULD
APPEAR TO SUPPORT ECMWF AS WELL.
THEREFORE KEPT HIGH CHANCE CATEGORY POPS FRIDAY WITH LOWER POPS
FRIDAY NIGHT. THERMAL PROFILES INDICATE A MIX OF RAIN AND SNOW
FRIDAY WITH SNOW FRIDAY NIGHT AS THE ARCTIC AIR MOVES IN.
SATURDAY LOOKS TO BE VERY COLD AND DRY WITH ARCTIC HIGH MOVING IN.
BEFORE THE ARCTIC FRONT ARRIVES THURSDAY EXPECT ABOVE NORMAL
TEMPERATURES.
&&
.AVIATION /DISCUSSION FOR THE 301800Z TAF ISSUANCE/...
ISSUED AT 1159 AM EST SAT NOV 30 2013
VFR EXPECTED THROUGH THE PERIOD...ALTHOUGH CONFIDENCE LOWERS AFTER
12Z SUNDAY.
WINDS COULD BRIEFLY GUST TO NEAR 15KT THIS AFTERNOON BUT MOST OF THE
TIME WINDS WILL BE LESS THAN 10KT UNDER JUST SOME HIGH CLOUDS.
LOW LEVEL MOISTURE INCREASES AHEAD OF A COLD FRONT TONIGHT SO ADDED
A CEILING AROUND BKN060 AFTER 06Z.
MODELS ARE TRYING TO HINT AT EVEN LOWER CEILINGS AFTER 12Z SUNDAY.
CONFIDENCE IS NOT HIGH IN THIS SCENARIO...BUT ODDS ARE GETTING
BETTER WITH EACH RUN. THEREFORE WILL LOWER CEILINGS TO LOW END OF
VFR FOR NOW.
&&
.IND WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
SYNOPSIS...RYAN
NEAR TERM...RYAN/JH
SHORT TERM...RYAN
LONG TERM....50
AVIATION...50
VISIT US AT HTTP://WWW.WEATHER.GOV/IND
FOLLOW US ON TWITTER AND YOUTUBE AT:
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WWW.YOUTUBE.COM/NWSINDIANAPOLIS
AREA FORECAST DISCUSSION
NWS INDIANAPOLIS IN
1159 AM EST SAT NOV 30 2013
.UPDATE...
THE AVIATION SECTION HAS BEEN UPDATED BELOW.
&&
.SYNOPSIS...
ISSUED AT 328 AM EST SAT NOV 30 2013
AFTER A MAINLY SUNNY DAY...CLOUDS WILL INCREASE ACROSS THE OHIO
VALLEY FOR THE SECOND HALF OF THE WEEKEND INTO EARLY NEXT WEEK AS A
WEAK FRONT SLIDES INTO THE REGION. A FEW LIGHT RAIN SHOWERS OR
SPRINKLES WILL BE POSSIBLE FROM SUNDAY AFTERNOON THROUGH MONDAY AS A
COUPLE OF WEAK WAVE ALOFT MOVE ACROSS THE OHIO VALLEY. A MUCH BETTER
CHANCE FOR RAIN WILL COME FOR THE SECOND HALF OF THE WEEK AS A
STRONG COLD FRONT TRACKS THROUGH THE REGION. COLDER AIR WILL ONCE
AGAIN RETURN BY THE END OF THE WEEK.
&&
.NEAR TERM /REST OF TODAY/...
ISSUED AT 954 AM EST SAT NOV 30 2013
UPDATE...
SOME MID/HIGH CLOUDS WERE STILL ACROSS OUR FAR EAST...BUT HAVE
CLEARED OUT ELSEWHERE. UPSTREAM SKIES WERE CLEAR AND WILL SCALE
BACK CLOUD COVER A LITTLE WITH MOST AREAS BEING SUNNY THIS
AFTERNOON.
ONLY OTHER CHANGE WAS TO TWEAK TEMPERATURES UP A DEGREE SOME AREAS
BASED ON 12Z RUC 2 METER TEMPERATURES...LOTS OF SUNSHINE AND WARM
ADVECTION. ALL IN ALL THE CURRENT FORECAST IS ON TRACK.
PREVIOUS NEAR TERM DISCUSSION FOLLOWS...
MID AND HIGH LEVEL CLOUD COVER DRAPED ACROSS MUCH OF THE OHIO VALLEY
EARLY THIS MORNING AS A WEAK WAVE ALOFT TRACKS ACROSS THE AREA.
TEMPS WERE MAINLY IN THE 20S AT 08Z.
BACK EDGE OF THE MORE SUBSTANTIAL HIGHER CLOUDS IS ALREADY EAST OF
THE MISSISSIPPI RIVER EARLY THIS MORNING. EXPECT CLOUDS TO DIMINISH
FROM WEST TO EAST ACROSS THE FORECAST AREA AROUND OR SHORTLY AFTER
DAYBREAK...WITH SKIES THEN BECOMING MOSTLY SUNNY WITH ONLY PATCHY
CIRRUS FOR THE REST OF THE DAY.
WITH THE BROAD HIGH PRESSURE RIDGE NOW LOCATED EAST OF THE
REGION...RETURN SOUTHERLY FLOW WILL DEVELOP AND INCREASE BY THIS
AFTERNOON AS BOUNDARY LAYER FLOW STRENGTHENS AHEAD OF AN APPROACHING
COLD FRONT. MODEL SOUNDINGS SUPPORT MAX GUSTS TO 20-25MPH BY THE
AFTERNOON AS LOW LEVEL MIXING INCREASES. GUSTS WILL DROP OFF NEAR
SUNSET AS THE NOCTURNAL INVERSION ESTABLISHES.
TEMPS...SOUTHERLY FLOW AND WARM ADVECTION WILL BRING WARMER TEMPS
INTO CENTRAL INDIANA FOR TODAY. MOS GUIDANCE MATCHES UP NICELY WITH
LOW LEVEL THERMALS...WITH HIGHS TOPPING OUT NEAR LATE NOVEMBER
NORMALS IN THE MID/UPPER 40S.
&&
.SHORT TERM /TONIGHT THROUGH MONDAY NIGHT/...
ISSUED AT 328 AM EST SAT NOV 30 2013
FORECAST CHALLENGES FOCUS ON POTENTIAL FOR LIGHT PRECIP AS THE
AFOREMENTIONED COLD FRONT DROPS INTO THE REGION...STALLS AND
EVENTUALLY WASHES OUT.
PREDOMINANT ZONAL FLOW IN THE UPPER LEVELS WILL BE PRESENT THROUGH
THE PERIOD WITH SEVERAL WEAK WAVES ALOFT TRACKING QUICKLY THROUGH
THE OHIO VALLEY. AT THE SURFACE...THE COLD FRONT WILL SLIDE SLOWLY
SOUTH INTO THE REGION ON SUNDAY...EVENTUALLY STALLING OUT OVER
SOUTHERN INDIANA SUNDAY NIGHT BEFORE WASHING OUT MONDAY. MOISTURE
ACCOMPANYING THE FRONT WILL BE LIMITED...BUT MODEL SOUNDINGS AND RH
PROGS CONTINUE TO SHOW IT IN GREATEST ABUNDANCE IN THE UPPER
PORTIONS OF THE BOUNDARY LAYER BEGINNING EARLY SUNDAY...GRADUALLY
LOWERING TO AROUND 2-3KFT INTO MONDAY AS AN INVERSION STEADILY
STRENGTHENS.
EXPECT CLOUDS TO EXPAND SOUTHEAST INTO THE FORECAST AREA AHEAD OF
THE FRONT BEGINNING LATE TONIGHT AND CONTINUING INTO SUNDAY. WEAK
ISENTROPIC LIFT AND A SUBTLE WAVE ALOFT MAY BE JUST ENOUGH TO
GENERATE SOME LIGHT PRECIP SUNDAY AFTERNOON AND NIGHT...LIKELY IN
THE FORM OF SPRINKLES...DRIZZLE OR VERY LIGHT RAIN SHOWERS. LOW
LEVELS AND SURFACE TEMPS SHOULD REMAIN WARM ENOUGH TO SUPPORT PRECIP
TYPE AS RAIN ONLY SUNDAY NIGHT. MODEL GUIDANCE LARGELY IN AGREEMENT
ON BRINGING A SLIGHTLY STRONGER...BETTER PHASED UPPER WAVE ACROSS
THE OHIO VALLEY ON MONDAY. WITH LOW LEVEL MOISTURE IN ABUNDANCE...
THIS FEATURE SHOULD PRESENT A BETTER OPPORTUNITY FOR A FEW LIGHT
RAIN SHOWERS. WILL CARRY JUST LOW CHANCE POPS HOWEVER AS ISENTROPIC
LIFT REMAINS WEAK. MAJORITY OF THE MODEL GUIDANCE FAVORING THE
PASSAGE OF THIS UPPER WAVE BY MONDAY EVENING...AND WILL END PRECIP
CHANCES AS RIDGING ALOFT EXPANDS INTO THE OHIO VALLEY BY EARLY
TUESDAY.
TEMPS...CONSIDERING THE INCREASING CLOUDS AND POTENTIAL FOR WEAK
COLD ADVECTION TO DEVELOP ON SUNDAY...METMOS TEMPS IN THE UPPER
40S/LOWER 50S LOOK RATHER AGGRESSIVE. HAVE TRENDED CLOSER TO /BUT
NOT AS COLD AS/ THE MAVMOS FOR SUNDAY HIGHS. LEANED TOWARDS THE
MAVMOS AGAIN FOR MONDAY WITH LIGHT RAIN/CLOUDS PRESENT. NEAR MAVMOS
FOR LOWS TONIGHT...THEN TRENDED TOWARDS THE WARMER METMOS FOR SUNDAY
NIGHT WITH EXPECTED CLOUD COVER.
&&
.LONG TERM /TUESDAY THROUGH FRIDAY/...
ISSUED AT 328 AM EST SAT NOV 30 2013
ENSEMBLES ARE IN GOOD AGREEMENT ON THE EVOLVING WEATHER PATTERN NEXT
WEEK. UPPER RIDGING EXPECTED TO DEVELOP ALONG THE EAST COAST AS A
TROUGH SETS UP FROM THE NORTHERN MIDWEST BACK INTO THE SOUTHERN
ROCKIES. THIS WILL RESULT IN SOUTHWESTERLY UPPER FLOW LOCALLY.
APPEARS A DECENT CHUNK OF ENERGY WILL EJECT OUT OF THE WESTERN
TROUGH INTO WESTERN GREAT LAKES AROUND NEXT THURSDAY. WILL KEEP POPS
IN THE FORECAST FOR RAIN ON WEDNESDAY AND ESPECIALLY THURSDAY AS THE
UPPER DISTURBANCE MOVES THROUGH.
SEVERAL ENSEMBLES SUGGEST MORE ENERGY MAY EJECT OUT ACROSS THE OHIO
OR TENNESSEE VALLEY AROUND NEXT FRIDAY...WHICH MAY INDUCE A SURFACE
WAVE ON THE PRIMARY COLD FRONT. WILL GO WITH CHANCE POPS FOR RAIN OR
SNOW AT THAT TIME. AT THIS POINT...THE ENSEMBLES INDICATE ANY SNOW
ACCUMULATIONS LATE NEXT WEEK WILL BE MINOR.
&&
.AVIATION /DISCUSSION FOR THE 301800Z TAF ISSUANCE/...
ISSUED AT 1159 AM EST SAT NOV 30 2013
VFR EXPECTED THROUGH THE PERIOD...ALTHOUGH CONFIDENCE LOWERS AFTER
12Z SUNDAY.
WINDS COULD BRIEFLY GUST TO NEAR 15KT THIS AFTERNOON BUT MOST OF THE
TIME WINDS WILL BE LESS THAN 10KT UNDER JUST SOME HIGH CLOUDS.
LOW LEVEL MOISTURE INCREASES AHEAD OF A COLD FRONT TONIGHT SO ADDED
A CEILING AROUND BKN060 AFTER 06Z.
MODELS ARE TRYING TO HINT AT EVEN LOWER CEILINGS AFTER 12Z SUNDAY.
CONFIDENCE IS NOT HIGH IN THIS SCENARIO...BUT ODDS ARE GETTING
BETTER WITH EACH RUN. THEREFORE WILL LOWER CEILINGS TO LOW END OF
VFR FOR NOW.
&&
.IND WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
SYNOPSIS...RYAN
NEAR TERM...RYAN/JH
SHORT TERM...RYAN
LONG TERM....JAS
AVIATION...50
VISIT US AT HTTP://WWW.WEATHER.GOV/IND
FOLLOW US ON TWITTER AND YOUTUBE AT:
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AREA FORECAST DISCUSSION...UPDATED
NWS ALBUQUERQUE NM
1136 AM MST SAT NOV 30 2013
.UPDATE...
LOW CLOUDS AND AREAS OF FOG ARE HANGING TOUGH ACROSS THE FOUR
CORNERS REGION. MODELS GENERALLY DO NOT HAVE A GOOD HANDLE ON WHEN
THE INVERSION WILL BREAK...BUT RUC SEEMS TO HAVE THE BETTER GRASP
OF ANY. INCREASED CLOUD COVER FOR THE AREA THROUGH THE
AFTERNOON...AND WITH THE EXPECTED CLOUD COVER...HAVE LOWERED TEMPS
A FEW DEGREES...ESPECIALLY FOR KFMN. UPDATES OUT SHORTLY.
34
&&
.PREV DISCUSSION...1109 AM MST SAT NOV 30 2013...
.AVIATION...
18Z TAF CYCLE
HIGH CIRRUS CLOUDS WILL STICK AROUND OVER THE SOUTHERN HALF TO
TWO THIRDS OF THE FORECAST AREA THROUGH THE NEXT 24 HOURS. LATEST
SATELLITE AND OBSERVATIONS SHOW SLOWLY IMPROVING CONDITIONS AT
GUP/FMN. THIS TREND SHOULD CONTINUE BUT THE MODELS HAVE HAD A HARD
TIME PREDICTING THE LIFR/IFR AND MVFR CONDTIONS. THESE CONDITIONS
SHOULD RETURN WITH ABUNDANT LOW LVL MOISTURE AND A STABLE
INVERSION TONIGHT. QUESTION IS WHEN. THINKING SLIGHTLY EARLIER
THAN LAST NIGHT AND THIS IS REFLECTED IN THE LATEST TERMINAL
FORECASTS AT GUP/FMN.
50
.PREV DISCUSSION...318 AM MST SAT NOV 30 2013...
LATEST GOES IMAGER FOG PRODUCT PICKING UP ON AN AREA OF FOG
ACROSS THE NORTHWEST PLATEAU...WEST OF THE DIVIDE TO NEAR GALLUP.
ONE QUARTER MILE VISIBILITY IN FREEZING FOG IN THE LATEST KFMN AND
KGUP OBS...LIKELY TO PERSIST BEYOND SUNRISE FOR A COUPLE OF HOURS.
STREAM OF PACIFIC MOISTURE RESULTING IN AN ELONGATED AREA OF DENSE
HIGH CLOUDS FROM THE EASTERN PACIFIC OCEAN...NORTHEAST ACROSS NW
MEXICO...SOUTHERN AZ AND NM MAKING FOR A TRICKY HIGH TEMPERATURE
FORECAST TODAY. THE UPPER FLOW TO BECOME MORE WESTERLY OVER THE
NEXT 24-36HRS...WHICH WILL CAUSE THE PACIFIC MOISTURE TAP TO SHIFT
SOUTH AND EAST OF OUR FORECAST AREA. HOWEVER...HIGH CLOUDS WILL
HANG AROUND AND MOVE ACROSS NM FROM THE NORTHWEST GOING INTO
MONDAY. BREEZY TO LOCALLY WINDY CONDITIONS FORECAST AS NW FLOW
INCREASES SUNDAY INTO MONDAY...WITH THE EAST SLOPES OF THE CENTRAL
MOUNTAIN CHAIN...ADJACENT HIGHLANDS AND PORTIONS OF THE EAST
CENTRAL PLAINS FAVORED FOR STRONGER WINDS.
WINDS ALOFT BACK FROM NW TO WSW TUESDAY INTO WEDNESDAY IN ADVANCE
OF A POTENT UPPER LEVEL TROUGH. TEMPS WILL TREND UP IN ADVANCE OF
THIS ANOMALOUSLY COLD SYNOPTIC WEATHER FEATURE AND WILL BE ABOVE
TO WELL ABOVE NORMAL TUESDAY AND TUESDAY NIGHT. A DEEPENING LEE
SIDE TROUGH WILL BE PARTIALLY RESPONSIBLE FOR INCREASING WINDS...
ESPECIALLY ACROSS THE NORTHEAST PLAINS AND HIGHLANDS.
TEMPS BEGIN A DOWNWARD TREND WEDNESDAY AS CLOUDS AND CHANCES FOR
PRECIPITATION TREND UP. A STRONG COLD FRONT TO MOVE EAST ACROSS
THE AREA LATE WEDNESDAY INTO THURSDAY...WITH A BACKDOOR PUSH DOWN
THE EASTERN PLAINS. WINDY CONDITIONS ARE FORECAST WEDNESDAY IN
ADVANCE OF AND IMMEDIATELY BEHIND THE COLD FRONT...MAY EVENT HIT
WIND ADVISORY THRESHOLDS IN A FEW SPOTS. PRECIP CHANCES LOOK TO
FAVOR THE NORTHERN AND WESTERN MOUNTAINS...ESPECIALLY WEDNESDAY AS
THE FRONT PUSHES THROUGH. SNOW ACCUMULATION MAY BE SIGNIFICANT
ENOUGH TO WARRANT ADVISORIES ACROSS THE NORTHERN MOUNTAINS. BOTH
THE LATEST ECMWF AND GFS SHOW THE UPPER LEVEL TROUGH AXIS PUSHING
THROUGH THURSDAY NIGHT INTO FRIDAY. THIS AIRMASS WILL LIKELY BE
THE COLDEST SO FAR THIS SEASON WITH THE LATEST MEDIUM RANGE MODELS
SHOWING NEAR -20C AT 700MB ALONG THE NM/CO BORDER BY 12Z FRIDAY.
THE BIG WEATHER STORY FROM LATE THURSDAY THROUGH INTO SATURDAY
WILL DEFINITELY BE THE WELL BELOW NORMAL TEMPERATURES.
11
.FIRE WEATHER...
A FEW MORE DAYS OF POOR VENTILATION WILL PLAGUE NORTHERN AND
CENTRAL NEW MEXICO BEFORE THE PATTERN SHIFTS TO A WINDIER ONE. A
CUT OFF LOW WILL STAY OVER THE EASTERN PACIFIC WATERS WITH HIGH
LEVEL MOISTURE STREAMING INTO NEW MEXICO TODAY. TEMPERATURES
SHOULD STILL REACH SEASONABLE AVERAGES FOR LATE NOVEMBER. LEE SIDE
SURFACE TROUGH WILL LOSE SOME STRENGTH BY AFTERNOON...AND THUS
AFTERNOON BREEZES WILL BE MODERATED IN EASTERN PARTS OF THE STATE
TODAY. THESE LIGHT WINDS AND STEEP INVERSIONS WILL PRODUCE THE
POOR MIXING AND INEFFICIENT DISPERSION. MINIMUM HUMIDITY WILL FALL
TO 25 TO 45 PERCENT ACROSS THE FORECAST AREA...RECOVERING TO 60 TO
80 PERCENT IN MOST OF THE EASTERN PLAINS TONIGHT AND UP TO 80 TO
100 PERCENT IN THE WEST THROUGH SUNDAY MORNING.
AS FLOW ALOFT TURNS MORE NORTHWESTERLY...A WEAK DISTURBANCE ALOFT
WILL SLIDE DOWN TOWARD NM TONIGHT AND SUNDAY...BUT THIS FEATURE
SHOULD POSE LITTLE ALTERATIONS TO THE OVERALL WEATHER ELEMENTS.
WHILE THE WINDS ALOFT WILL STRENGTHEN SOME SUNDAY AND
MONDAY...MIXING AND VENTILATION WILL STILL REMAIN POOR. LITTLE
TEMPERATURE VARIATION WILL ALSO BE NOTICED SUNDAY AND MONDAY.
BY TUESDAY FLOW ALOFT WILL BEGIN SHIFTING MORE SOUTHWESTERLY OVER NM
AS A TROUGH DEEPENS OVER THE WESTERN STATES. WINDS WILL INCREASE
SIGNIFICANTLY...ENOUGH TO IMPROVE VENTILATION BUT ALSO POTENTIALLY
INTRODUCING SOME NEAR-CRITICAL WINDS. AT THIS TIME FORECAST WIND
SPEEDS ARE BELOW CRITICAL CRITERIA...DUE TO SOME MODEL DISCREPANCIES
ON THE PLACEMENT OF THE LEE-SIDE SURFACE LOW. SHOULD MODELS CONVERGE
ON A MORE FAVORABLE PLACEMENT OF THIS FEATURE...WINDS MAY NEED TO BE
INCREASED. TEMPERATURES ARE EXPECTED TO STILL BE FAIRLY WARM ON
TUESDAY...ESPECIALLY IN THE EAST WITH DOWNSLOPING. HOWEVER...RH
FORECAST AT THIS TIME IS RESTING JUST ABOVE CRITICAL THRESHOLDS.
COOLER CONDITIONS AND BATCHES OF PRECIPITATION WILL BE SPREADING
INTO NM WEDNESDAY THROUGH THE END OF THE WORK WEEK AS THE BASE OF
THE AFOREMENTIONED TROUGH SWINGS THROUGH. WINDS WILL BE ELEVATED
THROUGH THIS PERIOD WITH BETTER VENTILATION...BUT NO CRITICAL
CONDITIONS ARE EXPECTED AS OF RIGHT NOW.
52
.AVIATION...
06Z TAF CYCLE
HIGH CLOUDS STREAMING NEWD AHEAD OF UPR LOW OFF SOCAL AND OVR NM.
SFC LEE TROF THRU 30/12Z THEN WK WND SHIFT EXPECTED IN THE ERN
PLNS AS SFC LOW SAGS SWD TO VCNTY KCVS. POTENTIAL FOR MVFR/IFR CIGS/VSBYS
FOUR CORNERS/KGUP REGION IN BR/FZFG PRIOR TO 15Z.
&&
.ABQ WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
34
AREA FORECAST DISCUSSION
NWS RALEIGH NC
1248 PM EST SAT NOV 30 2013
.SYNOPSIS...
HIGH PRESSURE WILL EXTEND SOUTHWEST INTO THE REGION THROUGH
TONIGHT...THEN WEAKEN ON SUNDAY. A LOW PRESSURE SYSTEM IS EXPECTED
TO DEVELOP ALONG THE CAROLINA COAST ON MONDAY AS AN UPPER LEVEL
DISTURBANCE APPROACHES FROM THE WEST.
&&
.NEAR TERM /THROUGH TODAY/...
AS OF 1050 AM SATURDAY...
SURFACE HIGH AS OF 15Z IS CENTERED WELL TO THE NORTHEAST...OVER NEW
ENGLAND AND INTO MAINE...WITH THE RIDGE AXIS EXTENDING SOUTHWEST INTO
NC...MAINLY ALONG THE WESTERN PORTION OF THE AREA. THE PRESSURE
GRADIENT WILL RELAX SOME AS THE HIGH MOVES OFF THE NE COAST AND THE
RIDGE WEAKENS...THUS ALLOWING THE WINDS TO RELAX SOME AS WELL. THE
RETURN FLOW WILL BECOME MORE NORTHEASTERLY AS THAT HAPPENS...
ALLOWING FOR WARMER TEMPS ACROSS THE SOUTH AND EAST AND COOLER IN
THE NW. THE 12Z UPPER AIR ANALYSES SHOW THE TROUGH... MORE PROMINENT
AT 700 AND 850 MB...EXTENDING FROM THE WESTERN GREAT LAKES SW INTO
OK/TX...WITH HIGH PRESSURE/RIDGING OVER THE EASTERN US. AN UPPER
LEVEL WAVE JUST WEST OF THE APPALACHIANS...SHOWN IN BOTH SATELLITE
IMAGERY AND INDICATED BY MODEL GENERATED VORTICITY PLOTS...IS
GENERATING AN AREA OF CLOUDS OVER WV/VA...WHICH MAY EXTEND INTO THE
NORTHERN AND WESTERN PORTIONS OF THE AREA TODAY...ALTHOUGH THE
GREATEST COVERAGE WILL BE OVER VA. WITH THE STRONG WESTERLY FLOW
ALOFT EXPECTED TO CONTINUE TODAY AS THE UPPER LEVEL RIDGE CONTINUES
TO BUILD...SUBSIDENCE SHOULD BE STRONG ENOUGH TO LIMIT MIXING IN THE
LOW LEVELS...WHICH IN COMBINATION WITH THE INCREASING CLOUD COVER...
SHOULD BE ENOUGH TO YIELD HIGHS TODAY A BIT COOLER THAN YESTERDAY...
MAINLY IN THE MID 40S TO LOW 50S. -KC
THE LATEST RAP...ALONG WITH THE HRRR WRF...FORECAST AN INCREASE IN
LOW-LEVEL MOISTURE FROM THE SOUTHEAST LATE IN THE DAY. THIS MAY BE
REASONABLE...AS THE SATELLITE FOG PRODUCT SHOWED AREAS OF LOW CLOUDS
JUST OFFSHORE FROM SOUTHEAST NORTH CAROLINA EARLY THIS MORNING. HAVE
ADDED SOME CLOUD COVER TO THE FORECAST PARTICULARLY TOWARD THE SOUTH
AND EAST DURING THE AFTERNOON. -DJF
&&
.SHORT TERM /TONIGHT THROUGH SUNDAY NIGHT/...
AS OF 650 AM SATURDAY...
SURFACE HIGH PRESSURE SHOULD BE DIRECTLY OVERHEAD OVERNIGHT KEEPING
THE GRADIENT VERY RELAXED. THE POTENTIAL FOR A QUITE CHILLY NIGHT
WOULD EXIST BUT THE COMBINATION OF SOME HIGH CLOUDS AND THE GFS
FORECAST OF INCREASING 850MB MOISTURE FROM THE SOUTH AND SOUTHWEST
MAY ACT TO KEEP TEMPERATURES CLOSE TO THE GUIDANCE LOWS OVERNIGHT.
THE LATEST SATELLITE FOG PRODUCT SHOWS LOW-LEVEL MOISTURE MOVING
WEST TOWARD THE SOUTH CAROLINA COAST...AND LOW-LEVEL ISENTROPIC
FORECASTS ALONG WITH THE INCREASING 850MB MOISTURE SUPPORT AN
INCREASE IN CLOUD COVER TO PARTLY-TO-MOSTLY CLOUDY PARTICULARLY
ALONG AND SOUTH OF ABOUT INTERSTATE 85 DURING THE OVERNIGHT HOURS.
THE TIMING OF THIS IS...OF COURSE...CRITICAL TO THE OVERNIGHT
TEMPERATURE FORECAST...BUT FOR THIS FORECAST WILL LEAN TOWARD THE
COOLER MOS GUIDANCE IN THE TRIAD AND THE WARMER MOS GUIDANCE
ELSEWHERE.
K INDICES SLOWLY RISE SUNDAY...WITH PRECIPITABLE WATER VALUES RISING
LATE SUNDAY TO BETWEEN 0.75 AND ONE INCH...ABOVE NORMAL FOR VERY
EARLY DECEMBER AT ABOUT THE 75TH PERCENTILE. LIFT STARTS TO INCREASE
LATE SUNDAY AND PARTICULARLY SUNDAY NIGHT AS ISENTROPIC LIFT ON THE
300K SURFACE INCREASES...WITH THE BEST POTENTIAL VORTICITY ON THE
1.5PVU SURFACE FORECAST BY THE GFS ALONG AND SOUTH OF ABOUT U.S. 64
LATE SUNDAY THROUGH SUNDAY NIGHT. SURFACE DEPICTIONS OF THE NAM AND
GFS DIFFER AND ARE FAIRLY CONSISTENT WITH THEMSELVES OVER THE LAST
TWO OR THREE RUNS...WITH THE NAM SHOWING A WEAK SURFACE LOW JUST OFF
THE SOUTH CAROLINA COAST SUNDAY NIGHT WHILE THE GFS FORECASTS MORE
OF AN INVERTED TROUGH BEFORE SURFACE LOW PRESSURE STRENGTHENS
OFFSHORE. REGARDLESS...QPF AND MOS GUIDANCE POPS ARE SIMILAR...
KEEPING MOST CHANCES FOR PRECIPITATION AT BAY SUNDAY AND INCREASING
CHANCES OVER MOST OF CENTRAL NORTH CAROLINA SUNDAY NIGHT. WILL NOTE
A SLIGHT CHANCE OF RAIN MAINLY OVER THE SANDHILLS AND SOUTHERN
COASTAL PLAIN SUNDAY WHERE THE BEST LOW-LEVEL MOISTURE SHOULD RESIDE
AS POTENTIAL VORTICITY INCREASES...WITH A CHANCE OF RAIN SUNDAY
NIGHT MAINLY ALONG AND EAST OF A LINE FROM ABOUT KIXA TO KAFP WITH A
SLIGHT CHANCE NORTH OF THAT LINE. DEBATED WHETHER OR NOT TO INCLUDE
A SLIGHT CHANCE IN THE TRIAD AND FOR THIS FORECAST WILL SHOW A VERY
LOW SLIGHT CHANCE THERE OVERNIGHT SUNDAY...THOUGH THIS COULD END UP
BEING OVERDONE WITH SUFFICIENT MOISTURE AND LIFT REMAINING JUST
EAST. SURFACE WET BULB TEMPERATURES AND PARTIAL THICKNESSES SUPPORT
ALL LIQUID.
ONCE AGAIN 1000-850MB THICKNESSES WOULD SUPPORT HIGHS SUNDAY ABOVE
MOS GUIDANCE...BUT GIVEN THE EXPECTED CLOUD COVER...WILL FORECAST
HIGHS AS A BLEND OF MAV AND MET MOS GUIDANCE FOR A FAIRLY UNIFORM
LOWER 50S IN MOST LOCATIONS. OVERNIGHT SUNDAY...IF IT REMAINS DRY IN
THE TRIAD LOWS SHOULD BE NEAR THE WARMER GUIDANCE...WHILE WHERE IT
RAINS TEMPERATURES WOULD APPROACH THE DEW POINT. THIS COINCIDES WITH
A BLEND OF MOS GUIDANCE...ALTHOUGH HIGHER THAN GUIDANCE TOWARD
KRWI...FOR LOWS IN THE MID TO UPPER 30S NORTHWEST...TO MID 40S
TOWARD KCTZ.
&&
.LONG TERM /MONDAY THROUGH FRIDAY/...
AS OF 235 AM SATURDAY...
ON MONDAY A LOW AMPLITUDE NORTHERN STREAM SHORTWAVE DROPS INTO THE
THE DEEP SOUTH AS A SHEARING SOUTHERN STREAM SYSTEM WITH A 250MB JET
OF 140 KTS PHASE TOGETHER BEFORE THE TROUGH AXIS MOVES OFF THE
SOUTHEAST COAST MONDAY NIGHT. THE TROUGH BECOMES NEGATIVELY TILTED
AND INITIATES SURFACE CYCLOGENESIS MONDAY NIGHT AND TUESDAY. RECENT
NWP TRENDS HAVE SUGGESTED A LESS AMPLIFIED SYSTEM WHILE PRODUCING A
BIT MORE QPF ACROSS MAINLY SOUTHEASTERN NC. IT REMAINS DIFFICULT AND
CONFIDENCE IS LOW REGARDING HOW FAR NORTH AND WEST PRECIPITATION
WILL SPREAD ACROSS CENTRAL NC BUT CONFIDENCE IS GROWING THAT SOME
LIGHT PRECIPITATION WILL FALL ACROSS THE SOUTHERN COASTAL PLAIN AND
SANDHILLS REGION. NWP CONSENSUS SHOWS THE DEEPEST MOISTURE AND
STRONGEST FORCING WILL BE CONFINED TO SOUTHEASTERN PORTIONS OF THE
RAH CWA WITH RAPIDLY DECREASING RAIN CHANCES ACROSS THE NORTHERN AND
WESTERN PIEDMONT. ISENTROPIC ANALYSIS DEPICTS THE PATTERN WELL WITH
A FAIRLY NARROW CORRIDOR OF LIFT/SATURATION THAT SLIDES MAINLY
ACROSS SOUTHERN AND EASTERN NC. PRECIPITATION CHANCES QUICKLY TAIL
OFF FROM WEST TO EAST ON MONDAY NIGHT. THE AIR MASS AHEAD OF THE
SYSTEM WILL HAVE MODIFIED AND THE PRECIPITATION WILL FALL AS RAIN.
GIVEN THE MODIFICATION OF THE AIR MASS AND THE LIGHT PRECIPITATION
CHANCES...DO NOT EXPECT A SIGNIFICANT CAD EVENT TO OCCUR. HIGHS
MONDAY WILL RANGE IN THE 49-56 RANGE WITH MAX TEMPERATURES DEPENDENT
ON THE LOCATION AND INTENSITY OF THE PRECIPITATION.
AFTER THE UPPER TROUGH AXIS MOVES OFFSHORE...THE FLOW ALOFT BECOMES
MORE NORTHWESTERLY. ANOTHER DISTURBANCE IN THE FLOW AND SOME
RESIDUAL MOISTURE SHOULD BE SUFFICIENT TO PRODUCE SOME CLOUDINESS ON
TUESDAY BUT OTHERWISE FAIR CONDITIONS ARE EXPECTED WITH HIGHS IN THE
LOWER TO MID 50S.
THE FLOW FLATTENS ON TUESDAY NIGHT AND HEIGHTS RISE ON WEDNESDAY
INTO THURSDAY WITH INCREASING HIGH CLOUDS LATE WEDNESDAY AND A FAIR
AMOUNT OF CLOUDS EXPECTED ON THURSDAY. EXPECT DRY WEATHER THROUGH AT
LEAST THURSDAY AFTERNOON AS THE RIDGE AXIS BUILDS OVERHEAD.
MODERATING TEMPERATURES ARE EXPECTED ON THURSDAY INTO FRIDAY WITH
HIGHS IN THE MID TO UPPER 50S ON WEDNESDAY WARMING INTO THE UPPER
50S TO LOWER 60S ON THURSDAY WITH MORNING LOWS IN THE MID 30S TO
AROUND 40.
A LONGWAVE TROUGH DEVELOPS OVER THE WESTERN U.S. LATE THURSDAY INTO
FRIDAY AS AN ARCTIC AIRMASS DROPS INTO THE NORTHERN ROCKIES AND
NORTHERN PLAINS. AN INCREASINGLY MOIST SOUTHERLY TO SOUTHWESTERLY
FLOW DEVELOPS ACROSS THE CENTRAL U.S. AS THE TROUGH PUSHES EAST ON
FRIDAY. THE ASSOCIATED COLD FRONT REACHES THE WESTERN APPALACHIANS
ON FRIDAY MORNING. THERE ARE TIMING DIFFERENCES AMONG THE GUIDANCE
REGARDING THE EASTWARD ADVANCEMENT OF THE FRONT AND THE ASSOCIATED
PRECIPITATION WITH WPC PREFERRING A GEFS MEAN AND EC ENS MEAN.
REGARDLESS...THE THREAT OF RAIN WILL ARRIVE WITH LOW PROBABILITIES
IN THE WEST LATE THURSDAY NIGHT. POPS WILL INCREASE FROM WEST TO
EAST FRIDAY AND FRIDAY NIGHT WITH THE BEST CHANCE OF RAIN AT THIS
POINT APPEARING TO BE FRIDAY NIGHT AND SATURDAY. AHEAD OF THE FRONT
AND THE RAIN...TEMPERATURES ARE LIKELY TO CLIMB INTO THE 60S FRIDAY
AFTERNOON. -BLAES
&&
.AVIATION /18Z SATURDAY THROUGH THURSDAY/...
AS OF 1245 PM SATURDAY...
24 HOUR TAF PERIOD: HIGH CONFIDENCE OF CONTINUED VFR CONDITIONS
THROUGH THIS AFTERNOON AND EVENING WITH THE RIDGE EXTENDING INTO NC
AND LIGHT NW WINDS. STILL EXPECT AN INCREASE IN LOW LEVEL MOISTURE
ACROSS THE COASTAL PLAIN OVERNIGHT AND INTO SUNDAY MORNING... WHICH
COULD YIELD A PERIOD OF SUB-VFR CONDITIONS...MAINLY AT KFAY...AND
POSSIBLY AT KRWI (LESS LIKELY TOWARD KRDU) AND POINTS ALONG AND
SOUTHEAST OF THERE. ALTHOUGH THE WINDS WILL BE LIGHT...THEY WILL BE
SLOWLY BACKING FROM PREDOMINANTLY NORTH AND NORTHEAST TO WEST AND
NORTHWEST BY THE END OF THE TAF PERIOD.
LOOKING AHEAD: EXPECT MOISTURE ADVECTION INTO THE AREA SUNDAY NIGHT
TO LEAD TO INCREASING CLOUD COVER AND THE CHANCE FOR RAIN. THERE IS
A GOOD CHANCE FOR SUB-VFR CONDITIONS DURING THIS TIME. EXPECT THE
ATMOSPHERE TO DRY FROM THE TOP DOWN ON TUESDAY...LIKELY IMPROVING
AVIATION CONDITIONS TO VFR FOR THE REMAINDER OF TUESDAY AND INTO
WEDNESDAY. SUB-VFR CONDITIONS ARE POSSIBLE AGAIN WEDNESDAY NIGHT
INTO THURSDAY AS SOUTHERLY FLOW ADVECTS MOISTURE INTO CENTRAL NC.
&&
.RAH WATCHES/WARNINGS/ADVISORIES...
NONE
&&
$$
SYNOPSIS...VINCENT
NEAR TERM...KC/DJF
SHORT TERM...DJF
LONG TERM...BLAES
AVIATION...KC
AREA FORECAST DISCUSSION
NWS BISMARCK ND
253 PM CST SAT NOV 30 2013
.SHORT TERM...(THIS EVENING THROUGH SUNDAY)
ISSUED AT 252 PM CST SAT NOV 30 2013
THE MAIN FORECAST CONCERNS IN THE SHORT TERM WILL BE PRECIPITATION
CHANCES LATE TONIGHT INTO SUNDAY. THERE IS GENERAL AGREEMENT AMONG
THE SHORT TERM MODELS THAT ANOTHER UPPER WAVE WILL MOVE ACROSS THE
NORTHERN PLAINS TONIGHT INTO SUNDAY AS AN H3 JET APPROACHES THE
REGION. THERE ARE SOME DIFFERENCES IN TIMING...BUT MOST SOLUTIONS
KEEP THE PRECIPITATION CHANCES WEST OF THE FORECAST AREA UNTIL LATE
TONIGHT. WILL SHOW INCREASING POPS IN THE WEST AFTER
MIDNIGHT...AND THEN SPREAD THE HIGHER POPS ACROSS WESTERN AND
CENTRAL NORTH DAKOTA ON SUNDAY.
PRECIPITATION TYPE WILL BE A CHALLENGE WITH THERMAL PROFILES
SUGGESTING MAINLY SNOW IN THE NORTH AND EAST...HOWEVER WARMER AIR
IS EXPECTED TO BE IN PLACE IN THE SOUTH AND WEST. HAVE GONE WITH A
MIX OF PRECIPITATION TYPES IN THE WEST CENTRAL AND SOUTHWEST LATE
TONIGHT AND SUNDAY. KEPT MOST SNOW AMOUNTS AN INCH OR LESS...AND
DID NOT CARRY ANY ICE ACCUMULATIONS DUE TO THE UNCERTAINTY STILL
SURROUNDING THE THERMAL PROFILES. LATER SHIFTS WILL HAVE TO KEEP
AN EYE ON HOW THINGS PROGRESS...BUT DO NOT HAVE ENOUGH CONFIDENCE
IN THE MIXED PRECIPITATION ACCUMULATING ENOUGH TONIGHT / SUNDAY TO
WARRANT THE ISSUANCE OF ANY ADVISORIES AT THE MOMENT.
.LONG TERM...(SUNDAY NIGHT THROUGH SATURDAY)
ISSUED AT 252 PM CST SAT NOV 30 2013
THE HIGHLIGHT OF THE EXTENDED FORECAST IS A POTENTIAL PROLONGED
SNOW EVENT MONDAY THROUGH WEDNESDAY...FOLLOWED BY VERY COLD ARCTIC
AIR.
THE 12 UTC DETERMINISTIC GUIDANCE IS IN GOOD AGREEMENT ON
SURFACE CYCLOGENESIS ACROSS SOUTHEAST ALBERTA AND INTO CENTRAL
MONTANA SUNDAY NIGHT INTO MONDAY. IN RESPONSE...A BAND OF
PREICPITATION IN LOW LEVEL ISENTROPIC LIFT IS FORECAST TO DEVELOP
ACROSS NORTHWEST AND INTO CENTRAL NORTH DAKOTA. PRECIPITATION IS
EXPECTED TO BE ALL SNOW ACROSS NORTHERN NORTH DAKOTA AND INTO THE
JAMES RIVER VALLEY. HOWEVER...A MIX OF FREEZING RAIN AND SLEET IS
POSSIBLE ON THE WESTERN PERIPHERY OF THE BAND...ESPECIALLY DURING
THE MORNING...WHERE A +1 TO +3 C MELTING LAYER ALOFT WILL BE IN
PLACE. A WINTER WEATHER ADVISORY MAY BE NEEDED FOR THIS EVENT AS
TWO TO FOUR INCHES OF SNOW ARE POSSIBLE ALONG AND NORTH OF US
HIGHWAY 2 AND INTO THE JAMES RIVER VALLEY...WITH POSSIBLE MINOR
ICE ACCUMULATIONS ACROSS THE SOUTH CENTRAL.
FOR THE MONDAY NIGHT THROUGH WEDNESDAY PORTION OF THE STORM...THE
12 UTC GFS/NAM AND 15 UTC SREF WERE DISCOUNTED AS THEY EJECT A
DEEP AND RAPIDLY PROPAGATING UPPER LEVEL LOW OUT OF THE MAIN
LONGWAVE. THIS IS MUCH DIFFERENT AND A SIGNIFICANT CHANGE FROM THE
PREFERRED 12 UTC ECMWF AND GEM SOLUTIONS. FOLLOWING THESE
SOLUTIONS...A PROLONGED PERIOD OF LIGHT TO MODERATE SNOW IS
EXPECTED FROM MONDAY NIGHT THROUGH WEDNESDAY ACROSS OF WESTERN AND
CENTRAL NORTH DAKOTA WITH A DEEP FETCH OF SOUTHWEST FLOW ALOFT.
HEAVY SNOWFALL ACCUMULATIONS ARE POSSIBLE...WITH BLOWING SNOW
BECOMING A THREAT WEDNESDAY ON THE BACKSIDE OF THE SURFACE LOW.
THEREAFTER...VERY COLD ARCTIC AIR TAKES OVER THE REGION INTO THE
WEEKEND.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SUNDAY AFTERNOON)
ISSUED AT 252 PM CST SAT NOV 30 2013
AFTERNOON VISIBLE SATELLITE IMAGERY SHOW STRATUS ACROSS PARTS OF
SOUTHERN CANADA MOVING SOUTH TOWARDS NORTHERN NORTH DAKOTA. THE
LATEST RAP MODEL SUGGESTS THE STRATUS COULD REACH KMOT AND BY LATE
AFTERNOON...AND THEN CONTINUE TO SPREAD SOUTH TONIGHT. LOWER
CLOUDS ARE ALSO POSSIBLE AS A CHANCE OF PRECIPITATION MOVES
TOWARDS THE REGION LATE TONIGHT INTO SUNDAY. OVERALL...WILL SHOW
A DOWNWARD TREND IN REGARDS TO CEILINGS...WITH VISIBILITY
RESTRICTIONS POSSIBLE AS PRECIPITATION CHANCES INCREASE.
&&
.BIS WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...CK
LONG TERM...AYD
AVIATION...CK
AREA FORECAST DISCUSSION
NWS BISMARCK ND
1258 PM CST SAT NOV 30 2013
.UPDATE...
ISSUED AT 1258 PM CST SAT NOV 30 2013
WEAK RADAR RETURNS CONTINUE ACROSS PARTS OF WEST AND SOUTH CENTRAL
NORTH DAKOTA EARLY THIS AFTERNOON. THE LATEST RAP STILL SHOWS
LIGHT PRECIPITATION ACROSS THE FAR SOUTHWEST FOR ANOTHER COUPLE
HOURS...SO WILL MAINTAIN A SLIGHT CHANCE POP IN THAT AREA. BAKER
MONTANA REPORTED LIGHT RAIN IN THE PAST HOUR...AND WITH SURFACE
TEMPERATURES ACROSS THE SOUTHWEST NOW IN THE MID 30S...THE PREVAILING
PRECIPITATION TYPE SHOULD BE RAIN.
UPDATE ISSUED AT 959 AM CST SAT NOV 30 2013
A WEAK UPPER WAVE WILL CONTINUE TO MOVE ACROSS WESTERN / SOUTHERN
NORTH DAKOTA TODAY. AREA RADARS SHOW WEAK RETURNS ACROSS WESTERN
AND CENTRAL NORTH DAKOTA...HOWEVER DRY AIR AS SHOWN IN THE 12Z
BISMARCK SOUNDING HAS PREVENTED MOST OF THE PRECIPITATION FROM
REACHING THE GROUND. THE 30.12Z NAM STILL SUGGESTS THERE COULD BE
LIGHT PRECIPITATION IN THE SOUTHWEST INTO EARLY AFTERNOON...SO
WILL KEEP A SLIGHT CHANCE POP IN THAT AREA. PRECIPITATION TYPE IS
ALSO A CHALLENGE WITH THERMAL PROFILES SUGGESTING MAINLY RAIN /
FREEZING RAIN THIS MORNING...BUT COOLER AIR BY EARLY AFTERNOON
COULD CAUSE A TRANSITION TO A RAIN / SNOW MIX.
STRATUS ACROSS THE EASTERN PART OF NORTH DAKOTA HAS BEEN TRENDING
STEADILY WESTWARD THIS MORNING. THE CURRENT FORECAST COVERS THIS
WELL IN THE SKY GRIDS...BUT DECIDED TO MODIFY HIGH TEMPERATURES
DOWNWARD A COUPLE OF DEGREES TOWARDS THE TURTLE MOUNTAINS WHERE
THE CLOUDS WILL ARRIVE FIRST.
UPDATE
ISSUED AT 637 AM CST SAT NOV 30 2013
WEAK EMBEDDED ENERGY MOVING EAST-SOUTHEAST ACROSS MONTANA
CONTINUES TO GENERATE EXTENSIVE CLOUDS FROM THE NORTHERN ROCKIES
EAST ACROSS WEST INTO SOUTH CENTRAL NORTH DAKOTA. WITH SFC OBS
REPORTING MAINLY OVC CONDITIONS...BEEFED UP SKY COVER. WILL
MAINTAIN SLIGHT CHANCES FOR SNOW OR LIGHT FREEZING RAIN WEST
CENTRAL INTO SOUTHWEST. EXPECT LITTLE MOISTURE IS REACHING THE
GROUND WITH CIGS OVER 5K FEET AGL. HOWEVER...DID HAVE REPORTS OF
-ZR AT WOLF POINT IN NORTHEAST MONTANA A COUPLE OF HOURS AGO...SO
ALTHOUGH LIMITED WE SHOULD SEE ISOLATED PRECIP.
CURRENT CLOUDS ARE PROJECTED TO REMAIN FOR MOST OF THIS MORNING IF
NOT THROUGH THE AFTERNOON WITH ANOTHER WEAK IMPULSE APPROACHING MY
NORTHWEST EARLY THIS AFTERNOON IN OUR NORTHWEST FLOW ALOFT.
LAST BIG CHANGE WITH THIS UPDATE WAS TO INCREASE CLOUDS OVER MY
NORTH CENTRAL TRENDING SOUTH. LARGE AREA OF LOW STRATUS TO OUR
NORTH ACROSS SOUTH CENTRAL CANADA IS SLOWLY MOVING SOUTH. LATEST
RAP AND NAM SHOW THE STRATUS REACHING MY NORTH CENTRAL/NORTHEAST
14-15Z THEN CONTINUING SOUTH AND EAST...REACHING THE JAMES VALLEY
18-21Z...AND THE SD BORDER BY MID EVENING...THEN PERSISTING
THROUGH THE NIGHT.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 501 AM CST SAT NOV 30 2013
REPORTS OF LIGHT FREEZING RAIN FROM NORTHEASTERN MONTANA CONFIRM
THAT SOME OF THE PRECIPITATION INDICATED ON RADAR IMAGERY IS
REACHING THE GROUND. IT APPEARS THIS ACTIVITY WILL SLOWLY SLIDE
SOUTHEAST TODAY. WHILE TRAVEL IMPACTS ARE NOT EXPECTED...THERE
COULD BE A BAND OR TWO OF PRECIPITATION THAT RESULTS IN ICY ROADS
BETWEEN WILLISTON AND HETTINGER...AND WESTWARD TODAY.
THERE WAS A LARGE SLOWDOWN IN THE ONSET OF PRECIPITATION FROM THE
FIRST SHORTWAVE DUE INTO THE STATE ON SUNDAY. NOW...THE 00 UTC
ECMWF/GFS/GEM GLOBAL/NAM ALL KEEP QPF OUT OF NORTH DAKOTA UNTIL
SUNDAY MORNING AROUND 3 AM CST. PRECIPITATION CHANCES WERE HELD TO
THE NORTHWESTERN COUNTIES UNTIL SUNRISE SUNDAY MORNING.
.LONG TERM...(SUNDAY THROUGH FRIDAY)
ISSUED AT 501 AM CST SAT NOV 30 2013
A PROLONGED PERIOD OF WINTER WEATHER REMAINS THE MAIN HIGHLIGHT IN
THE LONG TERM PERIOD...WITH INCREASING POTENTIAL FOR A MAJOR WINTER
STORM TUESDAY-WEDNESDAY NIGHT. 00Z MODELS HAVE TRENDED INTO MUCH
BETTER AGREEMENT FOR SUNDAY/SUNDAY NIGHT...WITH UNCERTAINTY
DECREASING QUITE A BIT FOR MONDAY. UNCERTAINTY STILL REMAINS
ELEVATED AFTERWARDS FOR TUESDAY AND ON.
UPPER LEVEL LOW PRESSURE OVER ALASKA HAS STARTED ITS SOUTHWARD
JOURNEY THIS MORNING...AND WILL TRACK SOUTH ALONG THE BRITISH
COLUMBIA COAST OVER THE WEEKEND DROPPING INTO THE PACIFIC NORTHWEST
ON MONDAY. AN UNASSOCIATED EMBEDDED S/WV IMPULSE CURRENTLY SOUTH OF
THIS FEATURE OVER THE NORTHEAST PACIFIC WILL TRACK EAST-SOUTHEAST
ONSHORE THIS MORNING THEN ACROSS THE ROCKIES TONIGHT ON THE NOSE OF
AN UPPER LEVEL JET. LEE SIDE SFC TROUGH DEVELOPS TONIGHT IN RESPONSE
TO THE INCREASING UPPER LEVEL DIVERGENCE. MODELS HAVE TRENDED SLOWER
WITH PRECIPITATION INITIALIZATION WITH THERMAL UPGLIDE EAST OF THE
TROUGH AND BEST DIVERGENCE ALOFT FOR ASCENT NOW TAKING PLACE OVER
WESTERN NORTH DAKOTA 12-18Z SUNDAY MORNING. OVERRUNNING FLOW AND
UPPER LEVEL SUPPORT IN THE LEFT EXIT REGION OF THE JET WILL SPREAD
EASTWARD SUNDAY AFTERNOON AND EVENING. THIS FIRST WAVE OF MOISTURE
STALLS ACROSS THE EAST GRADUALLY DIMINISHING AS FORCING WANES IN
RESPONSE TO DECREASING SUPPORT ALOFT. GENERALLY LIGHT QPF WITH THIS
FIRST WAVE UP TO A TENTH OF AN INCH OF MOISTURE...RESULTING IN
SNOWFALL AMOUNTS MAYBE AROUND AN INCH NORTH AND EAST. STILL
POTENTIAL FOR MIXED PRECIPITATION SOUTHWEST IN THE MORNING MAINLY IN
THE FORM OF SLEET WITH THE WARM LAYER WET BULB AROUND 1-3C. RAIN
WILL BE POSSIBLE ACROSS THE SOUTH CENTRAL WITH TEMPERATURES WARMING
TO NEAR 40F IN THE AFTERNOON.
MODELS HAVE COME INTO MUCH BETTER AGREEMENT WITH THE NEXT WAVE OF
MOISTURE...ASSOCIATED WITH A POTENT LEAD SHORT WAVE ORIGINATING WITH
THE UPPER LOW. PRECIPITATION IS FORECAST TO DEVELOP ACROSS MONTANA
SUNDAY EVENING...SPREADING EASTWARD SUNDAY NIGHT INTO MONDAY DAYTIME
ACROSS NORTH DAKOTA. MORE LIFT WILL BE PRESENT WITH THIS FEATURE
MAKING IT MORE PRODUCTIVE THAN SUNDAY`S DISTURBANCE WITH
PRECIPITATION PRODUCTION. QPF UP TO A QUARTER OF AN INCH WILL BE
ADVERTISED WRAPPING AROUND A SFC LOW FORECAST TO MOVE FROM EASTERN
MONTANA MONDAY MORNING INTO WESTERN SOUTH DAKOTA MONDAY EVENING.
THIS TRACK PUTS THE HIGHER QPF OVER MY NORTH..CENTRAL...AND EAST.
SIMILAR THERMAL PROFILE AS ON SUNDAY RESULTS IN ANOTHER CHANCE OF
MIXED PRECIPITATION SOUTHWEST. SFC TEMPS MAY BE WARMER RESULTING
IN MORE OF A RAIN/SNOW MIX VERSUS SLEET. IN FACT...MODELS WARM UP
THE SOUTHWEST AND SOUTH CENTRAL TO SUPPORT ALL RAIN LATER MONDAY
MORNING INTO THE AFTERNOON BEFORE CAA OVERTAKES THE STATE BY 00Z
TUESDAY. WITH THE HIGHER QPF WILL SEE HIGHER SNOWFALL
TOTALS...ONCE AGAIN ACROSS THE NORTH AND MY EAST WHERE ALL SNOW IS
FORECAST...UP TO 4 INCHES POSSIBLE. THUS WILL NEED TO KEEP A CLOSE
EYE ON MODEL TRENDS IN CASE A WINTER WEATHER ADVISORY BECOMES
NEEDED LATE SUNDAY NIGHT THROUGH MONDAY.
THIRD...FINAL...AND POSSIBLY GREATEST WAVE OF PRECIPITATION WILL
INITIATE WEST LATE MONDAY NIGHT...POTENTIALLY LASTING THROUGH
TUESDAY AND MUCH OF WEDNESDAY...AS THE UPPER LOW MOVES ACROSS THE
ROCKIES THEN LIFTS THROUGH THE NORTHERN PLAINS SOMETIME TUESDAY
NIGHT OR WEDNESDAY. STILL LOTS OF SPREAD AMONGST MODELS WITH A
VARIETY OF SOLUTIONS PRESENT WHEN COMPARING THE 00Z RUNS OF THE
GFS/GEM/ECMWF. THE LAST SEVERAL RUNS OF THE ECMWF HAVE BEEN THE
MOST CONSISTENT...WHICH BRINGS THE HEAVIEST SNOW AND STRONGEST
WINDS TO NORTH DAKOTA TUESDAY THROUGH WEDNESDAY NIGHT THANKS TO
AN INVERTED SFC TROUGH ACROSS THE DAKOTAS. BOTH THE GFS AND GEM
BRING LESS SNOW WITH THE GFS MUCH FASTER AND THE GEM FARTHER TO
THE SOUTH WITH LOW PRESSURE. WILL CONTINUE TO MONITOR MODEL TRENDS
CLOSE OVER THE NEXT FEW DAYS.
WHILE THE SNOW POTENTIAL REMAINS UNCERTAIN MID-WEEK...MORE
CONFIDENCE IN COLD ARCTIC AIR SURGING SOUTH IN THE UPPER LOWS WAKE
WEDNESDAY INTO FRIDAY...AND REMAINING ENTRENCHED OVER THE NORTHERN
PLAINS THROUGH NEXT WEEKEND. SUBZERO HIGHS ARE FORECAST...WITH
LOWS 20 BELOW OR COLDER.
WILL CONTINUE TO MENTION THE ABOVE HAZARDS IN A SPECIAL WEATHER
STATEMENT.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SUNDAY AFTERNOON)
ISSUED AT 1258 PM CST SAT NOV 30 2013
AFTERNOON VISIBLE SATELLITE IMAGERY SHOW STRATUS ACROSS PARTS OF
SOUTHERN CANADA MOVING SOUTH TOWARDS NORTHERN NORTH DAKOTA. THE
LATEST RAP MODEL SUGGESTS THE STRATUS COULD REACH KMOT AND BY LATE
AFTERNOON...AND THEN CONTINUE TO SPREAD SOUTH TONIGHT. LOWER
CLOUDS ARE ALSO POSSIBLE AS A CHANCE OF PRECIPITATION MOVES
TOWARDS THE REGION LATE TONIGHT INTO SUNDAY. OVERALL...WILL SHOW
A DOWNWARD TREND IN REGARDS TO CEILINGS...WITH VISIBILITY
RESTRICTIONS POSSIBLE AS PRECIPITATION CHANCES INCREASE.
&&
.BIS WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...CK
SHORT TERM...SCHECK
LONG TERM...NH
AVIATION...CK
AREA FORECAST DISCUSSION
NWS GRAND FORKS ND
1224 PM CST SAT NOV 30 2013
.UPDATE...
ISSUED AT 1224 PM CST SAT NOV 30 2013
ADJUSTED CLOUDS TO REFLECT CURRENT SAT TRENDS...AND ADDED SOME
PATCHY FOG IN THE NORTHWEST WHERE LANGDON OBS AND WEB CAMS SHOW
SOME REDUCED VIS. SOUTHWARD AND WESTWARD PROGRESSION OF THE LOW
CLOUDS HAS SLOWED A BIT...SO BUMPED UP HIGHS SLIGHTLY IN THE FAR
WEST AND SOUTHWEST WHERE THEY HAVE SEEN SOME SUN. LOWERED HIGHS A
BIT IN THE NORTH AND CENTRAL COUNTIES WHERE STRATUS HAS KEEP US
FROM RISING MORE THAN A FEW DEGREES.
UPDATE ISSUED AT 946 AM CST SAT NOV 30 2013
LOWERED HIGHS FOR TODAY ACROSS THE NORTHWESTERN COUNTIES AND
DROPPED THEM EVEN A DEGREE OR SO DOWN TO FARGO. CLEAR SKIES
ALLOWED TEMPS AROUND KDVL TO DROP INTO THE LOWER TEENS...AND WITH
STRATUS MOVING IN THERE WILL BE NOT TOO MUCH RISE THIS AFTERNOON.
AT THIS TIME THE SOUTHWESTERN CWA COULD STILL SEE SOME SUN AND
CLIMB INTO THE MID 30S...BUT THERE ARE MORE MID CLOUDS MOVING IN
FROM THE WEST. MADE SOME FURTHER TWEAKS TO CLOUDS AND WILL KEEP AN
EYE ON TEMPS IN CASE THEY NEED TO BE DROPPED MORE LATER ON TODAY.
UPDATE ISSUED AT 644 AM CST SAT NOV 30 2013
WILL NEED TO INCREASE SKY TODAY. THE RAP GUIDANCE IS VERIFYING THE
BEST...SHOWING THE LOW LEVEL CIGS FROM CANADA ADVECTING INTO THE
FORECAST AREA. WILL FOLLOW THE 09Z RAP FOR ARRIVAL TIMES. WILL
ALSO KEEP THE REGION CLOUDY THROUGH THE OVERNIGHT HOURS.
FORECASTED MAX TEMPS TODAY MAY BE A BIT HIGH...BUT SHOULD BE IN
THE BALL PARK. FORECASTED MIN TEMPS TONIGHT ARE LIKELY TOO COLD
(IF CLOUDS STICK AROUND AS EXPECTED). WILL CONCENTRATE ON SKY FOR
THIS UPDATE...AND WORRY ABOUT TEMPS WITH THE NEXT UPDATES.
&&
.SHORT TERM...(TODAY THROUGH SUNDAY)
ISSUED AT 337 AM CST SAT NOV 30 2013
00Z MODELS INITIALIZED WITH MINIMAL ERRORS AND ARE IN GOOD
AGREEMENT THROUGH SUNDAY. THE CHALLENGE FOR TODAY WILL BE
TEMPERATURES AND CLOUD COVER. THE CHALLENGE FOR SUNDAY WILL BE -SN
CHANCES.
TODAY-TONIGHT...WEAK COLD FRONT WILL BE THROUGH THE REGION WHICH
SHOULD LEAD TO SLIGHTLY COOLER TEMPERATURES THAN YESTERDAY. THE
MID-LEVEL CLOUDS ALONG AND AHEAD OF THIS FEATURE WILL MOVE
SOUTH...BUT WILL NEED TO WATCH THE LOW-LEVEL CIGS APPROACHING FROM
THE NORTH. 06Z RAP IS MOST AGGRESSIVE BRINGING THESE CIGS INTO THE
ENTIRE FA...WHILE MOST OTHER GUIDANCE SUGGESTS ONLY PORTIONS OF NW
MN WILL BE AFFECTED. WILL SIDE WITH THE MAJORITY...AND TAKE A
CLOSER LOOK AT THE 7AM UPDATE.
SUNDAY...00Z MODELS HAVE SLOWED THE SHORTWAVE BRINGING -SN
CHANCES...ADJUSTED POPS ACCORDINGLY. MUCH OF SUNDAY SHOULD BE DRY
(UNTIL THE EVENING HOURS).
.LONG TERM...(SUNDAY NIGHT THROUGH FRIDAY)
ISSUED AT 337 AM CST SAT NOV 30 2013
SUNDAY NIGHT-MONDAY NIGHT...00Z MODELS BEGIN TO DIVERGE...WITH THE
ECMWF/GEM/UKMET DIGGING THE UPPER LOW INTO THE NW CONUS BY 12Z
TUE...AND THE NAM/GFS BRINGING THIS FEATURE INTO MONTANA/WESTERN
DAKOTAS. THE ECMWF/GEM/UKMET HAVE BEEN THE MORE CONSISTENT
MODELS...AND ARE SUPPORTED BY ENSEMBLES (WILL FOLLOW FOR FORECAST
DETAILS). THERE WILL BE A COUPLE LEAD SHORTWAVES EJECTING FROM THE
MAIN UPPER TROUGH. THE FIRST WILL MOVE THROUGH THE REGION SUNDAY
NIGHT...AND THE SECOND MONDAY AFTERNOON/NIGHT. SINCE THERE HAVE
BEEN A FEW MODEL RUNS INDICATING THESE FEATURES...WILL INCREASE
POPS TO LIKELY AND ATTEMPT TO TIME THESE FEATURES THROUGH THE
REGION. THE FIRST WAVE IS WEAKER...AND SHOULD HAVE LESS AVAILABLE
MOISTURE. MESOSCALE FORCING IS ALSO WEAK...SO UP TO AN INCH OF
SNOWFALL APPEARS POSSIBLE (MAYBE 2 INCHES). THE SECOND WAVE IS
STRONGER...WITH MORE AVAILABLE MOISTURE (PWATS APPROACHING 0.5
INCHES). MODELS INDICATE A DEFINED CIRCULATION AT 850MB (AND A
WEAK 700MB LOW) PROPAGATING FROM NW ND INTO SE ND ON
MONDAY...LOSING DEFINITION MONDAY NIGHT AS IT PROPAGATES FURTHER
TO THE SE. ASSOCIATED WARM AIR ADVECTION/DEFORMATION COMBINED
WITH THE 0.5 INCH PWATS SHOULD LEAD TO A FEW INCHES OF SNOWFALL.
MODELS INDICATE 0.25-0.40 INCHES QPF ACROSS ALL BUT THE NE
FA...AND COMBINED WITH 12:1-13:1 SNOW RATIOS WOULD LEAD TO AN AREA
OF 3-5 INCHES OF SNOW. P-TYPE WILL BE ALL SNOW IF THE EXPECTED
SOLUTION VERIFIES. THE NAM/SREF/GFS HAVE WARMER MID-LEVEL
TEMPERATURES SINCE THE UPPER WAVE IS CLOSER TO THE REGION (LOW
LEVEL SOUTHERLY FLOW IS STRONGER)...AND WOULD LEAD TO FZRA/RA
POTENTIAL (BUT THIS PROBABILITY SEEMS VERY LOW ATTM).
TUESDAY-FRIDAY...A VERY WINTRY PERIOD IS IN STORE...WITH THE MAIN
FOCUS INITIALLY BEING SNOW POTENTIAL THROUGH MID-WEEK FOLLOWED BY
A COLD ARCTIC AIR MASS SPILLING SOUTH.
MODEL SPREAD CONTINUES TO BE SIGNIFICANT...ALTHOUGH THE ECMWF HAS
SHOWN BETTER CONSISTENCY OVER THE PAST FEW RUNS...SO HAVE TRENDED A
BIT IN THAT DIRECTION. THE 00Z GFS/ECMWF BOTH BRING THE UPPER TROUGH
EASTWARD INTO THE PLAINS WED/THU. HOWEVER...A CHALLENGE CONTINUES TO
BE TIMING OF EMBEDDED WAVES. THE ECMWF REMAINS DEEPEST AND FARTHEST
WEST WITH SFC LOW DEVELOPMENT FROM THE CENTRAL PLAINS NORTHEAST INTO
ONTARIO IN CONJUNCTION WITH A STRONG SHORTWAVE TROUGH ASSOCIATED
WITH THE LIFTING UPPER LOW...WHILE THE GFS IS MORE PROGRESSIVE WITH
A WEAKER SFC LOW ASSOCIATED WITH A LEAD WAVE. THUS...THE ECMWF AND
TO A LESSER EXTENT THE GEM ARE MORE AGGRESSIVE WITH QPF. THE 500 MB
GFS ENSEMBLE MEAN HEIGHT FIELD GENERALLY SUPPORTS THE ECMWF BROADLY.
CONFIDENCE STILL IS RATHER LOW REGARDING THE PLACEMENT AND MAGNITUDE
OF SNOWFALL...ALTHOUGH THE MID-WEEK PERIOD WILL CONTINUE TO BEAR
WATCHING FOR ACCUMULATING SNOWFALL.
ARCTIC AIR WILL BLAST SOUTH DURING THE LATTER PART OF THE
WEEK INTO NEXT WEEKEND. THE ECMWF CONTINUES TO INDICATE 925 MB TEMPS
DOWN TO -20 TO -25C THURSDAY/FRIDAY BEHIND INITIAL SURGE OF COLD
ADVECTION. BLUSTERY WINDS WILL COMBINE WITH VERY COLD TEMPS TO
PRODUCE POTENTIALLY HAZARDOUS WIND CHILLS AT TIMES.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SUNDAY AFTERNOON)
ISSUED AT 1224 PM CST SAT NOV 30 2013
MAIN CHALLENGE FOR AVIATION IS CIGS. BAND OF MVFR/IFR CIGS SPREADING
OVER THE AREA AND OBS UPSTREAM SHOWS SOME VARIANCE BETWEEN 800 TO
1500 FEET. HARD TO NAIL DOWN EXACT CIG HEIGHTS WITH THE STRATUS
DECK...SO WENT WITH PERSISTENCE ATTM AND KEPT CIGS GENERALLY AROUND
1000 FEET. EXPECT SOME VARIABILITY IN VSBY AS WELL...BUT WILL KEEP
IN VFR CATEGORY FOR NOW. OTHERWISE...VERY WEAK PRESSURE GRADIENT IS
EXPECTED TO PERSIST OVER THE AREA THRU THE TAF PERIOD SO KEPT WINDS
ON THE LIGHT SIDE.
&&
.FGF WATCHES/WARNINGS/ADVISORIES...
ND...NONE.
MN...NONE.
&&
$$
UPDATE...JR
SHORT TERM...TG
LONG TERM...TG/MAKOWSKI
AVIATION...HOPKINS
AREA FORECAST DISCUSSION
NWS ABERDEEN SD
1123 AM CST SAT NOV 30 2013
.UPDATE...
UPDATE TO 18Z AVIATION DISCUSSION BELOW.
NO MAJOR CHANGES MADE TO THE FORECAST THIS MORNING. CURRENT RADAR
IMAGES SHOW SOME WEAK ECHOES PUSHING OVER THE NORTHWESTERN CWA AT
THIS TIME...SO WILL STICK WITH A SCHC POP IN THAT AREA...WITH
LITTLE IN THE WAY OF RAINFALL ACCUMULATION EXPECTED. NO CHANGES
MADE TO WINDS OR TEMPERATURES AT THIS TIME.
&&
.PREVIOUS DISCUSSION...
.SHORT TERM...TODAY THROUGH MONDAY
CHANCES FOR PRECIPITATION AS WELL AS P-TYPE WILL BE THE FORECAST
CHALLENGES.
A WEAK MID LEVEL SHORT WAVE CURRENTLY OVER MONTANA WILL TRACK
SOUTHEASTWARD ACROSS THE REGION TODAY...BRINGING PARTLY CLOUDY
SKIES TO THE CWA. THE PAST FEW RUNS OF THE RUC AND THE NSSL WRF
BOTH SHOW SOME LIGHT RAIN FOR THE FAR NW PORTION OF THE
CWA...PERHAPS REACHING KMBG BY THIS AFTERNOON. THUS HAVE ADDED A
LOW POP.
ANOTHER MID LEVEL SHORT WAVE AND FRONTAL BOUNDARY WILL TRACK
ACROSS THE REGION ON SUNDAY. MODELS HAVE SIGNIFICANTLY SLOWED DOWN
THE PROGRESSION OF THE TROUGH...WITH PCPN NOT REACHING THE JAMES
RIVER VALLEY UNTIL AFTER 18Z. IT STILL APPEARS AS THOUGH THE
LEADING EDGE OF THE PCPN WILL FALL AS ALL SNOW. HOWEVER WITH WAA
QUICKLY PUSHING IN ON THE BACK SIDE...THE SNOW WILL TRANSITION
OVER TO ALL RAIN. THIS SYSTEM DOES NOT CONTAIN A GREAT DEAL OF LOW
LEVEL MOISTURE SO WILL MAINTAIN CHC POP ALONG THE ND/SD BORDER FOR
NOW. A MUCH STRONGER STORM SYSTEM WILL BEGIN IMPACTING THE REGION
ON MONDAY. HOWEVER MODELS ARE NOT IN A REAL GOOD AGREEMENT WITH THE
OVERALL PLACEMENT OF THIS MID LEVEL CLOSED LOW...WHICH LEADS TO A
LOW FORECASTER CONFIDENCE. EVEN WITH A DISAGREEMENT ON THE PLACEMENT
THERE IS A GENERAL CONSENSUS THAT TEMPERATURES WILL BE WARM ENOUGH
TO SUPPORT A MOSTLY RAIN EVENT.
.LONG TERM...MONDAY NIGHT THROUGH FRIDAY
STILL NOT A LOT OF CONFIDENCE WITH THE FINER DETAILS WITHIN THE
EXTENDED...THOUGH TWO GENERAL TRENDS CAN BE EXPECTED. THE FIRST
WILL BE THE INFLUENCE OF A BROAD UPPER TROF AND EMBEDDED
SHORTWAVES MOVING ACROSS THE NORTHERN TIER CONUS. MOST OF THE
PRECIPITATION WILL BE ASSOCIATED WITH AN H7 LOW THAT LOOKS TO
TRACK ACROSS NORTH DAKOTA/MINNESOTA...THOUGH IT MAY PIVOT THROUGH
WESTERN SOUTH DAKOTA DEPENDING ON THE MODEL. THIS TRACK SUGGESTS
NORTH DAKOTA WILL RECEIVE THE MAJORITY OF PRECIPITATION WITHIN THE
WARM ADVECTION BAND AND ANY TROWAL BASED WRAP AROUND. THE GFS IS
GENERALLY WEAKER WITH SIGNIFICANTLY LOWER PRECIPITATION POTENTIAL.
THE ECMWF IS STRONGER...WITH A MORE SOUTHERLY TRACK...AND STRONGER
WINDS WITH POTENTIALLY MORE IMPACTS TO THE CWA.
THE SECOND FEATURE WILL BE ANOMALOUSLY COLD AIR POURING INTO THE
REGION. TIMING DIFFERENCES CONTINUE BETWEEN THE GFS AND
ECMWF...VARYING BETWEEN TUESDAY AND WEDNESDAY RESPECTIVELY. BOTH
MODELS RESOLVE THE COLD POOL WITH SIMILAR INTENSITY AND
DURATION...AS IT WILL COME TO DOMINATE THE WEATHER THROUGH THE END
OF THE WORK WEEK.
UNFORTUNATELY...BOTH MODELS HAVE BEEN REASONABLY CONSISTENT WITH
THEIR INDIVIDUAL TRENDS. WILL CONTINUE TO BROADBRUSH THE FIRST FEW
PERIODS OF THE EXTENDED WITH CHANCE POPS/SNOW UNTIL MODELS ENTER
BETTER ALIGNMENT.
&&
.AVIATION...
18Z TAFS FOR THE KABR...KATY...KPIR AND KMBG TERMINALS
VFR CONDITIONS EXPECTED AT ALL TERMINALS WITH WINDS UNDER 10 KTS.
A MID LEVEL CLOUD DECK WILL MOVE ACROSS THE AREA TODAY AND
OVERNIGHT AOA 5 KFT.
&&
.ABR WATCHES/WARNINGS/ADVISORIES...
SD...NONE.
MN...NONE.
&&
$$
UPDATE...PARKIN
SHORT TERM...SD
LONG TERM...CONNELLY
AVIATION...SCARLETT
WEATHER.GOV/ABERDEEN
AREA FORECAST DISCUSSION
NWS SIOUX FALLS SD
1116 AM CST SAT NOV 30 2013
.UPDATE...
ISSUED AT 1116 AM CST SAT NOV 30 2013
TEMPERATURES WARMING EVEN FASTER THAN FORECAST AND CURRENTLY 5 TO
10 DEGREES WARMER THAN RAP AND NAM. WHILE STRONG INVERSION WILL
EVENTUALLY SLOW THE RISE...EXPECT THAT AREAS ALONG AND SOUTH OF
I90 WILL MIX TO AROUND 900 MB. THIS FAVORS TEMPERATURES CLOSE TO
50 ALONG I-90 AND INTO THE LOWER 50S IN THE MISSOURI VALLEY AND
PORTIONS OF NORTHWEST IOWA. DESPITE THE WARMER TEMPERATURES...
WINDS WILL NOT BE MUCH STRONGER...10 MPH OR LESS IN MOST AREAS.
DID NOT WARM QUITE AS MUCH ALONG HWY 14 IN EAST CENTRAL SD AND SW
MN DUE TO MORE CLOUDS THIS AFTERNOON.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 345 AM CST SAT NOV 30 2013
A MILD AND MUCH LESS WINDY DAY TODAY AS A WEAK BOUNDARY MOVES INTO
THE AREA. WHILE THE LOWER AND MID LEVEL THERMAL FIELD WILL BE A
LITTLE COOLER THAN YESTERDAY BETTER MIXING SHOULD SUPPORT WARMER
READINGS. WITH QUITE A FEW 50S TO THE WEST YESTERDAY AND THAT AIR
MASS MOVING INTO THE AREA WILL GO AHEAD AND RAISE IN MOST
LOCATIONS...ESPECIALLY WITH THE THOUGHT THAT CLOUD COVER WILL BE A
LITTLE LESS THROUGH MID AFTERNOON THAN PREVIOUSLY THOUGHT. DO EXPECT
SOME MID LEVEL CLOUDS TO REACH THE HIGHWAY 14 CORRIDOR BY ABOUT MID
DAY BUT THE INTERSTATE 90 CORRIDOR AND POINTS SOUTH SHOULD HOLD OFF
UNTIL AT LEAST MID AFTERNOON. FULL MIXING TO 900MB OR SO IN THE
SOUTHERN CWA SUPPORT ABOUT 52 TO 53 SO FOR NOW WILL GO ABOUT 50 IN
THIS AREA WHICH LEAVES A BIT OF WIGGLE ROOM IN CASE MIXING IS NOT
QUITE AS GOOD AS EXPECTED BUT WITH NO SNOW COVER SUSPECT THAT IT
WILL BE. THE REST OF THE AREA SHOULD BE MAINLY MID TO UPPER 40S WITH
SOME LOWER 40S ALONG THE HIGHWAY 14 CORRIDOR WHERE CLOUDS MOVE IN
QUICKER.
SHOULD BE FAIRLY MILD OVERNIGHT ALTHOUGH IT WILL BE A BATTLE BETWEEN
LIGHT WINDS...NO SNOW COVER AND SOME CLOUD COVER. WILL GO WITH
MAINLY UPPER TEENS TO LOWER 20S.
.LONG TERM...(SUNDAY THROUGH FRIDAY)
ISSUED AT 345 AM CST SAT NOV 30 2013
RELATIVELY QUIET WEATHER PATTERN CONTINUES INTO SUNDAY WITH LARGE
TROUGH BECOMING BETTER ORGANIZED OVER THE WEST COAST AND SURFACE
HIGH PRESSURE DOMINATING ACROSS THE EASTERN TWO THIRDS OF THE
COUNTRY. MODELS SHOW A FAIR AMOUNT OF MID AND HIGH LEVEL CLOUDS
STREAMING INTO THE FORECAST AREA. THERE IS EVEN SOME WEAK LIFT THAT
DEVELOPS ACROSS THE NORTHERN EDGE OF THE FORECAST AREA AS A WEAK
INITIAL WAVE PASSES BY...BUT THE LOWEST 4-5K FEET REMAIN UNSATURATED
MAKING IT TOUGH FOR THE PRECIPITATION TO REACH THE SURFACE. HAVE A
SLIGHT CHANCE OF RAIN OR SNOW IN THE LATE AFTERNOON HOURS ALONG THE
HIGHWAY 14 CORRIDOR...BUT OTHERWISE EXPECT DRY CONDITIONS TO
PREVAIL.
THROUGH THE EVENING HOURS SOUNDINGS WET BULB DOWN TO SNOW FAIRLY
QUICK AS ANOTHER WEAK WAVE PASSES TO THE NORTH. COULD SEE SOME
LIGHT SNOW WITH THIS WAVE ACROSS THE NORTHEAST HALF OF THE FORECAST
AREA SUNDAY NIGHT...BUT ANYTHING THAT FALLS WILL BE VERY LIGHT.
MONDAY APPEARS TO BE DRY AND SOMEWHAT MILD AS WARM FRONT PIVOTS
THROUGH THE REGION RESULTING IN A FAIR AMOUNT OF WARMING. 925 HPA
TEMPS WARM WELL INTO THE SINGLE DIGITS ABOVE FREEZING...AND HAVE
RAISED FORECAST HIGHS WITH GREATEST FOCUS FOR WARMING WEST OF THE
JAMES RIVER VALLEY. SOUTHERLY WINDS SHOULD AID IN THE
WARMING...WHILE A FAIR AMOUNT OF CLOUD COVER IS EXPECTED AS SURFACE
LOW WORKS IN NORTH DAKOTA.
MODEL AGREEMENT REALLY STARTS TO DISINTEGRATE THEREAFTER WITH GFS
OFFERING A MORE PROGRESSIVE EVOLUTION OF THE LOW THAN THE ECMWF.
WITH MODELS INDICATING A FAIRLY SIGNIFICANT CYCLONE AND JET ENERGY
HANGING BACK ON THE WEST SIDE OF THE TROUGH THROUGH AT LEAST MID DAY
TUESDAY...HAVE SIDED TOWARDS THE SLOWER EVOLUTION OF THIS SYSTEM.
CONTINUED MENTION OF MID RANGE POPS MONDAY NIGHT - TUESDAY WITH
INCREASE IN POPS ON WEDNESDAY. OVERALL...APPEARS AS THOUGH MUCH OF
THE MID AND UPPER LEVEL FORCING REMAINS TO THE NORTH AND WEST. IF
WE WERE ABLE TO GET PRECIP HERE...WOULD BE A TOUGH CALL BUT APPEARS
TO BE SOME SORT OF MIXTURE TO THE SOUTH WITH SNOW DOMINANTLY FALLING
ACROSS THE NORTH AND WEST.
MODELS SHOW FALLING TEMPERATURES ON WEDNESDAY THROUGH THE REMAINDER
OF THE EXTENDED AS INVERTED TROUGH SHIFTS THROUGH WITH MUCH COOLER
AIR POURING INTO THE NORTHERN PLAINS. HAVE SQUASHED THE DIURNAL
RANGE ON WEDNESDAY ACROSS THE WEST...WITH LESS MANIPULATION FURTHER
TO THE SOUTH AND EAST. HAVE ALSO LOWERED FORECAST HIGHS ON THURSDAY
WITH -15 TO -17 DEGREE AIR ACROSS THE FORECAST AREA AT 925 HPA.
HAVE ALSO RAISED WINDS CLOSER TO MOS VALUES UNDER THE INFLUENCE OF
STRONG COLD AIR ADVECTION. AT THIS POINT...DID NOT GO STRONGLY
COOL...AS LIMITED SNOW COVER MAY AID IN SOME MIXING.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SUNDAY AFTERNOON)
ISSUED AT 1116 AM CST SAT NOV 30 2013
LIGHT WINDS AND VFR CLOUDS AND CIGS EXPECTED THROUGH 18Z AT TAF
LOCATIONS...KFSD...KSUX AND KHON. CIGS WILL BE LOWERING OVERNIGHT
AND INTO SUNDAY MORNING ACROSS SE SD AS WARM FRONT APPROACHES BUT
WITH VERY DRY LOW LEVEL AIR MASS DO NOT EXPECT PRECIPITATION TO
DEVELOP. HOWEVER...CIGS COULD FALL TO AS LOW AS 4000 FT ON SUNDAY
MORNING. OTHER CONCERN IS STRATUS IN THE RED RIVER VALLEY OF ND
AND NW MN. LOW LEVEL TRAJECTORIES BRING THESE CLOUDS INTO THE
MINNESOTA RIVER VALLEY THIS EVENING AND MAY RESULT IN MVFR CIGS AS
FAR WEST AS KMML AND KMWM THIS EVENING BEFORE CLOUDS BEGIN TO MOVE
EAST TOWARD SUNRISE. WINDS THROUGH THE PERIOD WILL BE LESS THAN 10
KTS...FROM THE NORTHWEST THIS AFTERNOON AND EVENING...AND FROM THE
SOUTHEAST ON SUNDAY MORNING.
&&
.FSD WATCHES/WARNINGS/ADVISORIES...
SD...NONE.
MN...NONE.
IA...NONE.
NE...NONE.
&&
$$
UPDATE...SCHUMACHER
SHORT TERM...08
LONG TERM...
AVIATION...SCHUMACHER
AREA FORECAST DISCUSSION...UPDATED
NWS ABERDEEN SD
1021 AM CST SAT NOV 30 2013
.UPDATE...
NO MAJOR CHANGES MADE TO THE FORECAST THIS MORNING. CURRENT RADAR
IMAGES SHOW SOME WEAK ECHOES PUSHING OVER THE NORTHWESTERN CWA AT
THIS TIME...SO WILL STICK WITH A SCHC POP IN THAT AREA...WITH
LITTLE IN THE WAY OF RAINFALL ACCUMULATION EXPECTED. NO CHANGES
MADE TO WINDS OR TEMPERATURES AT THIS TIME.
&&
.PREVIOUS DISCUSSION...
.SHORT TERM...TODAY THROUGH MONDAY
CHANCES FOR PRECIPITATION AS WELL AS P-TYPE WILL BE THE FORECAST
CHALLENGES.
A WEAK MID LEVEL SHORT WAVE CURRENTLY OVER MONTANA WILL TRACK
SOUTHEASTWARD ACROSS THE REGION TODAY...BRINGING PARTLY CLOUDY
SKIES TO THE CWA. THE PAST FEW RUNS OF THE RUC AND THE NSSL WRF
BOTH SHOW SOME LIGHT RAIN FOR THE FAR NW PORTION OF THE
CWA...PERHAPS REACHING KMBG BY THIS AFTERNOON. THUS HAVE ADDED A
LOW POP.
ANOTHER MID LEVEL SHORT WAVE AND FRONTAL BOUNDARY WILL TRACK
ACROSS THE REGION ON SUNDAY. MODELS HAVE SIGNIFICANTLY SLOWED DOWN
THE PROGRESSION OF THE TROUGH...WITH PCPN NOT REACHING THE JAMES
RIVER VALLEY UNTIL AFTER 18Z. IT STILL APPEARS AS THOUGH THE
LEADING EDGE OF THE PCPN WILL FALL AS ALL SNOW. HOWEVER WITH WAA
QUICKLY PUSHING IN ON THE BACK SIDE...THE SNOW WILL TRANSITION
OVER TO ALL RAIN. THIS SYSTEM DOES NOT CONTAIN A GREAT DEAL OF LOW
LEVEL MOISTURE SO WILL MAINTAIN CHC POP ALONG THE ND/SD BORDER FOR
NOW. A MUCH STRONGER STORM SYSTEM WILL BEGIN IMPACTING THE REGION
ON MONDAY. HOWEVER MODELS ARE NOT IN A REAL GOOD AGREEMENT WITH THE
OVERALL PLACEMENT OF THIS MID LEVEL CLOSED LOW...WHICH LEADS TO A
LOW FORECASTER CONFIDENCE. EVEN WITH A DISAGREEMENT ON THE PLACEMENT
THERE IS A GENERAL CONSENSUS THAT TEMPERATURES WILL BE WARM ENOUGH
TO SUPPORT A MOSTLY RAIN EVENT.
.LONG TERM...MONDAY NIGHT THROUGH FRIDAY
STILL NOT A LOT OF CONFIDENCE WITH THE FINER DETAILS WITHIN THE
EXTENDED...THOUGH TWO GENERAL TRENDS CAN BE EXPECTED. THE FIRST
WILL BE THE INFLUENCE OF A BROAD UPPER TROF AND EMBEDDED
SHORTWAVES MOVING ACROSS THE NORTHERN TIER CONUS. MOST OF THE
PRECIPITATION WILL BE ASSOCIATED WITH AN H7 LOW THAT LOOKS TO
TRACK ACROSS NORTH DAKOTA/MINNESOTA...THOUGH IT MAY PIVOT THROUGH
WESTERN SOUTH DAKOTA DEPENDING ON THE MODEL. THIS TRACK SUGGESTS
NORTH DAKOTA WILL RECEIVE THE MAJORITY OF PRECIPITATION WITHIN THE
WARM ADVECTION BAND AND ANY TROWAL BASED WRAP AROUND. THE GFS IS
GENERALLY WEAKER WITH SIGNIFICANTLY LOWER PRECIPITATION POTENTIAL.
THE ECMWF IS STRONGER...WITH A MORE SOUTHERLY TRACK...AND STRONGER
WINDS WITH POTENTIALLY MORE IMPACTS TO THE CWA.
THE SECOND FEATURE WILL BE ANOMALOUSLY COLD AIR POURING INTO THE
REGION. TIMING DIFFERENCES CONTINUE BETWEEN THE GFS AND
ECMWF...VARYING BETWEEN TUESDAY AND WEDNESDAY RESPECTIVELY. BOTH
MODELS RESOLVE THE COLD POOL WITH SIMILAR INTENSITY AND
DURATION...AS IT WILL COME TO DOMINATE THE WEATHER THROUGH THE END
OF THE WORK WEEK.
UNFORTUNATELY...BOTH MODELS HAVE BEEN REASONABLY CONSISTENT WITH
THEIR INDIVIDUAL TRENDS. WILL CONTINUE TO BROADBRUSH THE FIRST FEW
PERIODS OF THE EXTENDED WITH CHANCE POPS/SNOW UNTIL MODELS ENTER
BETTER ALIGNMENT.
&&
.AVIATION...
12Z TAFS FOR THE KABR...KATY...KPIR AND KMBG TERMINALS
VFR CONDITIONS EXPECTED AT ALL TERMINALS. LIGHT WINDS WILL BE OUT
OF THE NORTHWEST GRADUALLY SHIFTING TO THE NORTH.
&&
.ABR WATCHES/WARNINGS/ADVISORIES...
SD...NONE.
MN...NONE.
&&
$$
UPDATE...PARKIN
SHORT TERM...SD
LONG TERM...CONNELLY
AVIATION...CONNELLY
WEATHER.GOV/ABERDEEN