Forecast Discussions mentioning any of
"HRRR" "RAP" "RR" "RUC13" "RUC" received at GSD on 12/28/13
AREA FORECAST DISCUSSION
NWS TAUNTON MA
1015 AM EST THU DEC 26 2013
.SYNOPSIS...
A WEAK...FAST MOVING DISTURBANCE WILL BRING A MIX OF RAIN AND
SNOW FOR THE REGION TODAY. WHILE COOL FOR FRIDAY...MILDER
CONDITIONS MOVE IN FOR THE WEEKEND. LOW PRESSURE WILL MOVE
NORTHEAST FROM THE GULF OF MEXICO WILL PASS NEAR NANTUCKET SUNDAY
NIGHT...THEN MOVE SOUTH OF NOVA SCOTIA MONDAY MORNING. FRIGID AIR
WILL INVADE THE REGION BY TUESDAY.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
955 AM UPDATE...
BAND OF LIGHT SNOW HAS DEVELOPED ACROSS EASTERN MA AS SEEN ON
LATEST KBOX 88D RADAR IMAGERY. MORE LIGHT SNOW HAS MOVED INTO S
NH/W MA/N CENTRAL CT AHEAD OF APPROACHING LOW PRES MOVING OUT OF
THE GREAT LAKES THIS MORNING. NOTING LIGHT RAIN REPORTED ALONG THE
S COAST WITH TEMPS MAINLY IN THE MID TO UPPER 30S WITH S-SE WINDS
UP TO 10 MPH...WHILE LIGHT NORTHERLY WINDS CONTINUE WHERE THE SNOW
HAS BROKEN OUT.
TEMPS/DEWPTS HAVE BEEN RUNNING SEVERAL DEGS LOWER THAN PREVIOUS
FORECAST ACROSS THE INTERIOR SO HAVE ADJUSTED TO BRING CURRENT.
THIS MAY SLOW THE TEMP RISE A BIT ACROSS INTERIOR E MA/N RI.
REMAINING GRIDS ALSO UPDATED TO BRING CURRENT.
PREVIOUS DISCUSSION...
STRONGER NORTHERN STREAM IMPULSE THROUGH THE BROADER TROUGH
REGIME INVOKES A WEAK AREA OF LOW PRES SOUTH AND OFFSHORE OF NEW
ENGLAND WITHIN THE BETTER BAROCLINIC ZONE BY MIDDAY...QUICKLY
MOVING NORTHEASTWARD AND AMPLIFYING ACROSS THE GULF OF MAINE BY
EVENING.
EXPECT THE HEAVIEST OF PRECIP IMPACTS E-SE PORTIONS OF SOUTHERN
NEW ENGLAND WITH ONE TO TWO TENTHS /THE GREATEST OF WHICH WILL BE
ACROSS THE EASTERN CAPE AND NANTUCKET/. LESSER AMOUNTS EXPECTED
FOR THE NORTH AND WEST INTERIOR. CLOUDS ON THE INCREASE SOUTH AND
WEST PRESENTLY WILL BEGIN TO CLEAR OUT LATE.
BUT SOME QUESTION AS TO HOW QUICKLY ARCTIC AIR WILL SCOUR OUT. NOT A
ROBUST SYSTEM AND ONSHORE SOUTHERLY FLOW WILL BE LIGHT. WHILE MILDER
AIR WILL WORK IN SOUTH TO NORTH...CONSIDERING HOW LONG WE HAVE BEEN
IN AN ARCTIC GRIP...FEEL THE PROGRESSION OF MILDER AIR WILL BE SLOW
AGAINST THE ARCTIC AIRMASS. SUSPECT COASTAL LOCATIONS AND ADJACENT
PLAINS WILL WARM ABOVE FREEZING...WHILE INTERIOR LOCALES /ESPECIALLY
THOSE WITH A REMAINING SNOWPACK/ WILL STAY AT OR BELOW FREEZING
THROUGHOUT THE EVENT. WHILE THE HRRR MAY BE TOO COLD...THE WRF-ARW
2M TEMPS ARE A GOOD APPROXIMATION AS TO THINKING.
IN THE END...SNOW IS EXPECTED INITIALLY MIXING OVER TO RAIN FOR
COASTAL COMMUNITIES AND ADJACENT PLAINS...WITH MAINLY ALL SNOW FOR
THE NORTHERN AND WESTERN INTERIOR /NORTH AND WEST OF I-84 TO I-90 TO
I-95 AS AN APPROXIMATION/. ROUGHLY 1 TO 2 INCHES FOR THE HIGHER
TERRAIN OF THE BERKSHIRES/WORCESTER HILLS/MONADNOCKS...WITH A TRACE
TO AN INCH ELSEWHERE EXCEPT COASTAL COMMUNITIES. FOR AREAS MIXING
OVER TO RAIN...INITIAL SNOW ACCUMS WILL ALL BUT WASH AWAY.
HIGHS TODAY AROUND THE UPPER 20S TO LOW 30S /WARMEST CONDITIONS
ALONG THE IMMEDIATE SHORES...CAPE AND ISLANDS/.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH 6 PM FRIDAY/...
TONIGHT....
HIGH PRES AND COLDER AIR WORKING IN. WHILE THE SYSTEM CLEARS OUT...
WILL SEE SOME LOW- TO MID-LEVEL CLOUDS LINGER ASSOCIATED WITH FETCH
OFF THE LAKES AND ADDITIONAL WEAK IMPULSES ROUNDING THE BROADER FLOW
REGIME ALOFT. COLD AIR ADVECTION THROUGH THE LOW-LEVELS ALLOWS FOR
STEEPENING LAPSE RATES. MIX-DOWN OF FASTER MOMENTUM CERTAINLY
POSSIBLE WITH GUSTS OF 20 TO 25 MPH...ESPECIALLY ALONG THE SOUTH-
SOUTHEAST COAST WITH ADJACENT WARMER WATERS. NOT ARCTIC COLD...LOWS
AROUND THE UPPER-TEENS TO LOW-20S /WARMER ALONG IMMEDIATE SHORES/.
FRIDAY...
HIGH PRES CONTINUING TO BUILD...SHIFTING SOUTH AND EAST. WILL SEE
WESTERLY FLOW DIMINISH TURNING SOUTHWESTERLY...BECOMING LIGHT.
LINGERING LOW- TO MID-LEVEL CLOUDS WITH FETCH OFF THE LAKES. STILL
COLD WITH H925 TEMPS AROUND -4 TO -6C /H85 AROUND -10C/. HIGHS
AROUND THE LOW- TO MID-30S ANTICIPATED.
&&
.LONG TERM /FRIDAY NIGHT THROUGH WEDNESDAY/...
BIG PICTURE... UPPER LOW CENTERED OVER BAFFIN ISLAND/HUDSON BAY WITH
CYCLONIC FLOW OVER THE NORTHEAST USA WEAKENING EARLY IN THE
FORECAST...THEN STRENGTHENING AGAIN BY NEW YEARS EVE. THIS
CONTINUES TO FAVOR MODERATING TEMPS OVER THE WEEKEND...THEN A RETURN
TO BELOW NORMAL TEMPS EARLY NEXT WEEK. THE MAIN CHANGE IN THIS
PATTERN SEEMS TO BE A 24-HOUR DELAY IN THE ONSET OF NEXT WEEK/S
CHILL. THE UPPER JET AND SOUTHWEST FLOW DON/T MOVE EAST OF NEW
ENGLAND UNTIL MONDAY NIGHT.
MEANWHILE THE NORTHERN AND SOUTHERN UPPER JETS ARE NOW FORECAST TO
PHASE DURING SUNDAY...ALLOWING SOUTHERN STREAM SHORTWAVE TO TAP A
MORE PRONOUNCED BAROCLINIC ZONE AS IT MOVES PAST NEW ENGLAND. THE
PHASING SUGGESTS DEEPENING OF THE UPPER TROUGH TO OUR WEST RESULTING
IN MORE OF A SOUTHWEST FLOW ALOFT. THIS LEAVES ROOM FOR THE SURFACE
COASTAL LOW TO EDGE CLOSER TO THE COAST LATER SUNDAY/SUNDAY NIGHT.
THIS IS A STORMIER SCENARIO FOR US THAN WAS DEPICTED 24 HOURS AGO.
WE WILL NEED TO MONITOR THAT THIS SUDDEN CHANGE DOESN/T GO BACK THE
OTHER WAY JUST AS FAST.
MODELS... GFS AND ECMWF ARE SIMILAR WITH THEIR SURFACE ISOBARS/UPPER
CONTOURS/UPPER JET WIND SPEEDS THROUGH SUNDAY NIGHT. SMALL
DIFFERENCES DEVELOP MONDAY THROUGH WEDNESDAY. WE FAVOR A BLEND OF
THE LONG RANGE GUIDANCE.
THE DAILIES...
FRIDAY NIGHT-SATURDAY... COLD NORTHWEST FLOW FLATTENS TO A WEST-EAST
FLOW AS SHORTWAVES IN THE NORTHERN AND SOUTHERN STREAMS MOVE INTO
THE PLAINS. THE NORTHERN STREAM SUPPORTS A STALLED COLD FRONT ALONG
THE CANADIAN BORDER WITH LOW PRESSURE WAVES RIPPLING ALONG IT.
MEANWHILE HIGH PRESSURE IS IN PLACE ACROSS THE SOUTHEAST AND MID
ATLANTIC STATES. LIGHT FLOW AND DRY AIR WILL ALLOW FRIDAY NIGHT
TEMPS TO DIP INTO THE TEENS AND 20S. THEN THE MILDER AIR WILL START
FLOWING IN A WEST-SOUTHWEST FLOW. CLOUDS ASSOCIATED WITH THE
STALLED COLD FRONT WILL AFFECT NORTHERN NEW ENGLAND SATURDAY AND MAY
BRING PARTLY CLOUDY SKIES TO PARTS OF OUR AREA. BUT OVERALL IT WILL
BE A FAIR DAY WITH TEMPS REACHING THE UPPER 30S AND 40S.
SUNDAY-MONDAY... SOUTHERN STREAM LOW PRESSURE DEVELOPS OVER THE GULF
OF MEXICO LATE SATURDAY AND MOVES UP THE EAST COAST ON SUNDAY. AS
NOTED ABOVE...THE TWO JET STREAMS ARE NOW EXPECTED TO PHASE ON
SUNDAY ALLOWING THE COASTAL SYSTEM TO MOVE CLOSER TO THE COAST. IF
THIS VERIFIES...IT WILL ALLOW PRECIPITATION TO REACH MOST OR ALL OF
OUR AREA LATER SUNDAY AND SUNDAY NIGHT. TEMPS IN THE VERTICAL WILL
BE ABOVE FREEZING SOUTH OF THE MASS PIKE WHILE AREAS FARTHER NORTH
MAY HAVE TEMPS EITHER SIDE OF FREEZING. THIS WILL MEAN RAIN FOR OUR
SOUTHERN AREAS AND A RAIN/SNOW MIX IN THE NORTH...POSSIBLY ALL SNOW
IN SOUTHERN NH. THE CURRENT MODEL INFORMATION IS NOTICEABLY
DIFFERENT FROM THE INFO 24 HOURS AGO SO CONFIDENCE IS VERY LIMITED
FOR THIS FORECAST. ALSO SMALL CHANGES IN THE FLOW OVER THE NEXT 3-4
DAYS COULD PUSH THE RAIN TEMPERATURES FARTHER NORTH OR THE SNOW
TEMPERATURES FARTHER SOUTH. SO STAY TUNED. THE UPPER FLOW WILL
REMAIN OPEN TO THE EAST ALLOWING THE COASTAL STORM TO RACE OFF
THROUGH THE MARITIMES SUNDAY NIGHT. MONDAY LOOKS SUNNIER/DRIER AND
COOLER...BUT NOT UNSEASONABLY SO.
TUESDAY-WEDNESDAY... WITH THE UPPER JET MOVING OFFSHORE MONDAY
NIGHT...THE WAY WILL BE OPEN FOR ARCTIC AIR TO RETURN TO SOUTHERN
NEW ENGLAND. TEMPS AT 925 MB WILL BE 10C COLDER WITH VALUES TUESDAY
AT -12C TO -14C. FULLY MIXED THIS WOULD SUPPORT MAX TEMPS IN THE
20S. DEWPOINTS WILL DIVE TO THE SINGLE NUMBERS AND BELOW ZERO. THIS
WILL MAKE ROOM FOR NIGHTTIME MIN TEMPS IN THE SINGLE NUMBERS AND
LOWER TEENS.
&&
.AVIATION /15Z THURSDAY THROUGH MONDAY/...
FORECASTER CONFIDENCE LEVELS...
LOW...LESS THAN 30 PERCENT.
MODERATE...30 TO 60 PERCENT.
HIGH...GREATER THAN 60 PERCENT.
NEAR TERM /THROUGH FRIDAY/...HIGH CONFIDENCE.
10 AM UPDATE...
MAINLY MVFR TO LOCALLY IFR CONDITIONS ACROSS E MA/RI INTO S
CENTRAL NH WITH -SN /-RA ACROSS SE MA AND RI/. VFR CONDITIONS
ACROSS SW NH/CENTRAL-W MA AND N CT WILL BECOME LOCALLY MVFR IN
-SN. ALSO EXPECT BRIEF IFR CONDITIONS ACROSS HIGHER INLAND
TERRAIN.
PREVIOUS DISCUSSION...
IMPROVEMENT BEGINS TOWARDS EVENING AS WINDS REVERT WESTERLY AND
BECOME BLUSTERY...GUSTS DEVELOPING OVERNIGHT INTO FRIDAY THE
STRONGEST OF WHICH WILL LIKELY IMPACT SHORELINE TERMINALS. LOW TO
MID LEVEL CLOUDS FEW-SCT WILL LIKELY FILTER ACROSS THE TERMINALS.
KBOS TAF...HIGH CONFIDENCE IN TAF. LOWER CONFIDENCE WITH EXACT
TIMING OF IMPACTS. INITIAL SNOW ACCUMS OF AROUND A TENTH OR TWO IN
THE MORNING WILL WASH AWAY AS SNOW MIXES OVER TO RAIN DURING THE
MORNING HOURS.
KBDL TAF...HIGH CONFIDENCE IN TAF. MUCH OF THE ACTIVITY STAYS EAST
OF THE TERMINAL. EXPECTING JUST SOME FLURRIES TO A BRIEF LIGHT
SNOW SHOWER THAT WILL YIELD AROUND A TRACE OF SNOW ACCUM AT MOST.
OUTLOOK...FRIDAY NIGHT THROUGH MONDAY
FRIDAY NIGHT THROUGH SUNDAY MORNING...HIGH CONFIDENCE. VFR.
SUNDAY AFTERNOON THROUGH MONDAY...MODERATE CONFIDENCE. CIGS AND
VSBYS WILL LOWER TO MVFR IN DEVELOPING RAIN SUNDAY AFTERNOON AND
EVENING. PRECIPITATION MAY MIX WITH SNOW OR BECOME ALL SNOW IN
SOUTHERN NH AND PARTS OF NORTHERN MASS. IFR CONDITIONS POSSIBLE
SUNDAY NIGHT. PRECIPITATION ENDS BY MONDAY MORNING AND CONDITIONS
WILL IMPROVE TO VFR.
&&
.MARINE...
FORECASTER CONFIDENCE LEVELS...
LOW...LESS THAN 30 PERCENT.
MODERATE...30 TO 60 PERCENT.
HIGH...GREATER THAN 60 PERCENT.
NEAR TERM /THROUGH FRIDAY/...HIGH CONFIDENCE.
10 AM UPDATE...
SOUTHERLY WINDS BEGINNING TO INCREASE ACROSS THE SOUTHERN OPEN
WATERS. NOTING PK WND UP TO 25 KT AT BUZZARDS BAY TOWER AT 15Z AND
23 KT AT 44013. SEAS AROUND 3 FT AT THE BUOYS...WHICH WILL SLOWLY
BUILD THIS AFTERNOON AS WINDS INCREASE. HAVE CONTINUED SMALL
CRAFTS AS EXPECT WINDS/SEAS TO MAKE CRITERIA AS WEAK LOW
APPROACHES. MAY SEE PERIOD OF LIGHT SNOW ACROSS THE EASTERN WATERS
N OF CAPE COD EARLY...OTHERWISE SHOULD SEE LIGHT RAIN WITH SOME
VSBY RESTRICTIONS.
PREVIOUS DISCUSSION...
OVERNIGHT...COVERAGE OF SMALL CRAFT ADVISORIES EXTENDS IN
RESPONSE TO WINDS BACKING OUT OF THE WEST BEHIND THE DEPARTING
SYSTEM AND BECOMING BLUSTERY WITH GUSTS UP TO 25 KTS. CONDITIONS
CONTINUE THROUGH FRIDAY. SEAS BUILDING OVER THE OUTER WATERS...5
TO 7 FEET.
OUTLOOK...FRIDAY NIGHT THROUGH MONDAY...
MODERATE CONFIDENCE.
FRIDAY NIGHT-SATURDAY...WEST TO SOUTHWEST WINDS MAY GUST NEAR 25
KNOTS. SEAS WILL SUBSIDE BELOW 5 FEET FRIDAY NIGHT...BUT THEN BUILD
ON SATURDAY TO 5-7 FEET ESPECIALLY ON THE OUTER WATERS. A SMALL
CRAFT ADVISORY MAY BE NEEDED FOR PARTS OF THE MASS AND RI WATERS.
SUNDAY...COASTAL LOW PRESSURE MOVES UP THE EAST COAST. VARIABLE
WINDS WILL BECOME NORTHEAST LATE SUNDAY AND THEN NORTHWEST MONDAY.
SPEEDS WILL BE AROUND 25 KNOTS...WHILE THE EXPOSED WATERS WILL SEE
SEAS BUILD TO 5 TO 7 FEET. SMALL CRAFT ADVISORY MAY BE NEEDED FOR
PARTS OF THE MASS AND RI WATERS.
&&
.BOX WATCHES/WARNINGS/ADVISORIES...
CT...NONE.
MA...NONE.
NH...NONE.
RI...NONE.
MARINE...SMALL CRAFT ADVISORY FROM 6 PM THIS EVENING TO 2 AM EST FRIDAY
FOR ANZ231-232-251.
SMALL CRAFT ADVISORY FROM 6 PM THIS EVENING TO MIDNIGHT EST
TONIGHT FOR ANZ233-234.
SMALL CRAFT ADVISORY FROM 4 PM THIS AFTERNOON TO 2 AM EST
FRIDAY FOR ANZ235-237.
SMALL CRAFT ADVISORY FROM 1 PM THIS AFTERNOON TO 7 PM EST
FRIDAY FOR ANZ250-254>256.
&&
$$
SYNOPSIS...WTB/SIPPRELL
NEAR TERM...WTB/EVT
SHORT TERM...SIPPRELL
LONG TERM...WTB
AVIATION...WTB/SIPPRELL/EVT
MARINE...WTB/SIPPRELL/EVT
AREA FORECAST DISCUSSION
NWS TAUNTON MA
632 AM EST THU DEC 26 2013
.SYNOPSIS...
A WEAK AND QUICK DISTURBANCE WILL BRING A MIX OF RAIN AND SNOW FOR
THE REGION TODAY. WHILE COOL FOR FRIDAY...MILDER CONDITIONS MOVE
IN FOR THE WEEKEND. LOW PRESSURE WILL MOVE NORTHEAST FROM THE
GULF OF MEXICO WILL PASS NEAR NANTUCKET SUNDAY NIGHT...THEN MOVE
SOUTH OF NOVA SCOTIA MONDAY MORNING. FRIGID AIR WILL INVADE THE
REGION BY TUESDAY.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
7 AM UPDATE...
PATCHY LIGHT FLAKES. OTHERWISE CLOUDS AND DRY AIR. DEWPOINT
DEPRESSIONS AT 6 AM WERE RUNNING 5-10F. MAIN CHANGE TO FORECAST IS
TO REMOVE FREEZING DRIZZLE...HARD TO SEE THIS WITH DEWPOINT
DEPRESSIONS AS THEY ARE.
PREVIOUS DISCUSSION...
STRONGER NORTHERN STREAM IMPULSE THROUGH THE BROADER TROUGH
REGIME INVOKES A WEAK AREA OF LOW PRES SOUTH AND OFFSHORE OF NEW
ENGLAND WITHIN THE BETTER BAROCLINIC ZONE BY MIDDAY...QUICKLY
MOVING NORTHEASTWARD AND AMPLIFYING ACROSS THE GULF OF MAINE BY
EVENING.
DURING THIS AMPLIFICATION...ATTENDANT DYNAMICS AND JET STREAK
ENHANCE SOUTH-SOUTHWESTERLY LOW- TO MID-LEVEL FLOW RESULTING IN
LOCALIZED MOISTURE CONVERGENCE ALONG THE LEADING WARM-FRONT /N-NE
QUADRANT OF THE SURFACE LOW/ WHERE FRONTOGENESIS/ISENTROPIC FORCING
IS MAXIMIZED.
ALREADY THIS MORNING...RADAR ECHOES ARE BUILDING ACROSS UPSTATE NY
OUT AHEAD OF THE NORTHERN STREAM IMPULSE...WHILE PER SATELLITE
TRENDS...LOW CLOUDS AND MOISTURE ARE BEING DRAWN UP FROM THE SOUTH.
SO WITH CERTAINTY...THE HEAVIEST OF PRECIP IMPACTS E/SE PORTIONS OF
SOUTHERN NEW ENGLAND WITH ONE TO TWO TENTHS /THE GREATEST OF WHICH
WILL BE ACROSS THE EASTERN CAPE AND NANTUCKET/. LESSER AMOUNTS
EXPECTED FOR THE NORTH AND WEST INTERIOR. CLOUDS ON THE INCREASE
SOUTH AND WEST PRESENTLY WILL BEGIN TO CLEAR OUT LATE.
BUT SOME QUESTION AS TO HOW QUICKLY ARCTIC AIR WILL SCOUR OUT. NOT A
ROBUST SYSTEM AND ONSHORE SOUTHERLY FLOW WILL BE LIGHT. WHILE MILDER
AIR WILL WORK IN SOUTH TO NORTH...CONSIDERING HOW LONG WE HAVE BEEN
IN AN ARCTIC GRIP...FEEL THE PROGRESSION OF MILDER AIR WILL BE SLOW
AGAINST THE ARCTIC AIRMASS. SUSPECT COASTAL LOCATIONS AND ADJACENT
PLAINS WILL WARM ABOVE FREEZING...WHILE INTERIOR LOCALES /ESPECIALLY
THOSE WITH A REMAINING SNOWPACK/ WILL STAY AT OR BELOW FREEZING
THROUGHOUT THE EVENT. WHILE THE HRRR MAY BE TOO COLD...THE WRF-ARW
2M TEMPS ARE A GOOD APPROXIMATION AS TO THINKING.
IN THE END...SNOW IS EXPECTED INITIALLY MIXING OVER TO RAIN FOR
COASTAL COMMUNITIES AND ADJACENT PLAINS...WITH MAINLY ALL SNOW FOR
THE NORTHERN AND WESTERN INTERIOR /NORTH AND WEST OF I-84 TO I-90 TO
I-95 AS AN APPROXIMATION/. ROUGHLY 1 TO 2 INCHES FOR THE HIGHER
TERRAIN OF THE BERKSHIRES/WORCESTER HILLS/MONADNOCKS...WITH A TRACE
TO AN INCH ELSEWHERE EXCEPT COASTAL COMMUNITIES. FOR AREAS MIXING
OVER TO RAIN...INITIAL SNOW ACCUMS WILL ALL BUT WASH AWAY.
HIGHS TODAY AROUND THE UPPER-20S TO LOW-30S /WARMEST CONDITIONS
ALONG THE IMMEDIATE SHORES...CAPE AND ISLANDS/.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH 6 PM FRIDAY/...
TONIGHT....
HIGH PRES AND COLDER AIR WORKING IN. WHILE THE SYSTEM CLEARS OUT...
WILL SEE SOME LOW- TO MID-LEVEL CLOUDS LINGER ASSOCIATED WITH FETCH
OFF THE LAKES AND ADDITIONAL WEAK IMPULSES ROUNDING THE BROADER FLOW
REGIME ALOFT. COLD AIR ADVECTION THROUGH THE LOW-LEVELS ALLOWS FOR
STEEPENING LAPSE RATES. MIX-DOWN OF FASTER MOMENTUM CERTAINLY
POSSIBLE WITH GUSTS OF 20 TO 25 MPH...ESPECIALLY ALONG THE SOUTH-
SOUTHEAST COAST WITH ADJACENT WARMER WATERS. NOT ARCTIC COLD...LOWS
AROUND THE UPPER-TEENS TO LOW-20S /WARMER ALONG IMMEDIATE SHORES/.
FRIDAY...
HIGH PRES CONTINUING TO BUILD...SHIFTING SOUTH AND EAST. WILL SEE
WESTERLY FLOW DIMINISH TURNING SOUTHWESTERLY...BECOMING LIGHT.
LINGERING LOW- TO MID-LEVEL CLOUDS WITH FETCH OFF THE LAKES. STILL
COLD WITH H925 TEMPS AROUND -4 TO -6C /H85 AROUND -10C/. HIGHS
AROUND THE LOW- TO MID-30S ANTICIPATED.
&&
.LONG TERM /FRIDAY NIGHT THROUGH WEDNESDAY/...
BIG PICTURE... UPPER LOW CENTERED OVER BAFFIN ISLAND/HUDSON BAY WITH
CYCLONIC FLOW OVER THE NORTHEAST USA WEAKENING EARLY IN THE
FORECAST...THEN STRENGTHENING AGAIN BY NEW YEARS EVE. THIS
CONTINUES TO FAVOR MODERATING TEMPS OVER THE WEEKEND...THEN A RETURN
TO BELOW NORMAL TEMPS EARLY NEXT WEEK. THE MAIN CHANGE IN THIS
PATTERN SEEMS TO BE A 24-HOUR DELAY IN THE ONSET OF NEXT WEEK/S
CHILL. THE UPPER JET AND SOUTHWEST FLOW DON/T MOVE EAST OF NEW
ENGLAND UNTIL MONDAY NIGHT.
MEANWHILE THE NORTHERN AND SOUTHERN UPPER JETS ARE NOW FORECAST TO
PHASE DURING SUNDAY...ALLOWING SOUTHERN STREAM SHORTWAVE TO TAP A
MORE PRONOUNCED BAROCLINIC ZONE AS IT MOVES PAST NEW ENGLAND. THE
PHASING SUGGESTS DEEPENING OF THE UPPER TROUGH TO OUR WEST RESULTING
IN MORE OF A SOUTHWEST FLOW ALOFT. THIS LEAVES ROOM FOR THE SURFACE
COASTAL LOW TO EDGE CLOSER TO THE COAST LATER SUNDAY/SUNDAY NIGHT.
THIS IS A STORMIER SCENARIO FOR US THAN WAS DEPICTED 24 HOURS AGO.
WE WILL NEED TO MONITOR THAT THIS SUDDEN CHANGE DOESN/T GO BACK THE
OTHER WAY JUST AS FAST.
MODELS... GFS AND ECMWF ARE SIMILAR WITH THEIR SURFACE ISOBARS/UPPER
CONTOURS/UPPER JET WIND SPEEDS THROUGH SUNDAY NIGHT. SMALL
DIFFERENCES DEVELOP MONDAY THROUGH WEDNESDAY. WE FAVOR A BLEND OF
THE LONG RANGE GUIDENCE.
THE DAILIES...
FRIDAY NIGHT-SATURDAY... COLD NORTHWEST FLOW FLATTENS TO A WEST-EAST
FLOW AS SHORTWAVES IN THE NORTHERN AND SOUTHERN STREAMS MOVE INTO
THE PLAINS. THE NORTHERN STREAM SUPPORTS A STALLED COLD FRONT ALONG
THE CANADIAN BORDER WITH LOW PRESSURE WAVES RIPPLING ALONG IT.
MEANWHILE HIGH PRESSURE IS IN PLACE ACROSS THE SOUTHEAST AND MID
ATLANTIC STATES. LIGHT FLOW AND DRY AIR WILL ALLOW FRIDAY NIGHT
TEMPS TO DIP INTO THE TEENS AND 20S. THEN THE MILDER AIR WILL START
FLOWING IN A WEST-SOUTHWEST FLOW. CLOUDS ASSOCIATED WITH THE
STALLED COLD FRONT WILL AFFECT NORTHERN NEW ENGLAND SATURDAY AND MAY
BRING PARTLY CLOUDY SKIES TO PARTS OF OUR AREA. BUT OVERALL IT WILL
BE A FAIR DAY WITH TEMPS REACHING THE UPPER 30S AND 40S.
SUNDAY-MONDAY... SOUTHERN STREAM LOW PRESSURE DEVELOPS OVER THE GULF
OF MEXICO LATE SATURDAY AND MOVES UP THE EAST COAST ON SUNDAY. AS
NOTED ABOVE...THE TWO JET STREAMS ARE NOW EXPECTED TO PHASE ON
SUNDAY ALLOWING THE COASTAL SYSTEM TO MOVE CLOSER TO THE COAST. IF
THIS VERIFIES...IT WILL ALLOW PRECIPITATION TO REACH MOST OR ALL OF
OUR AREA LATER SUNDAY AND SUNDAY NIGHT. TEMPS IN THE VERTICAL WILL
BE ABOVE FREEZING SOUTH OF THE MASS PIKE WHILE AREAS FARTHER NORTH
MAY HAVE TEMPS EITHER SIDE OF FREEZING. THIS WILL MEAN RAIN FOR OUR
SOUTHERN AREAS AND A RAIN/SNOW MIX IN THE NORTH...POSSIBLY ALL SNOW
IN SOUTHERN NH. THE CURRENT MODEL INFORMATION IS NOTICEABLY
DIFFERENT FROM THE INFO 24 HOURS AGO SO CONFIDENCE IS VERY LIMITED
FOR THIS FORECAST. ALSO SMALL CHANGES IN THE FLOW OVER THE NEXT 3-4
DAYS COULD PUSH THE RAIN TEMPERATURES FARTHER NORTH OR THE SNOW
TEMPERATURES FARTHER SOUTH. SO STAY TUNED. THE UPPER FLOW WILL
REMAIN OPEN TO THE EAST ALLOWING THE COASTAL STORM TO RACE OFF
THROUGH THE MARITIMES SUNDAY NIGHT. MONDAY LOOKS SUNNIER/DRIER AND
COOLER...BUT NOT UNSEASONABLY SO.
TUESDAY-WEDNESDAY... WITH THE UPPER JET MOVING OFFSHORE MONDAY
NIGHT...THE WAY WILL BE OPEN FOR ARCTIC AIR TO RETURN TO SOUTHERN
NEW ENGLAND. TEMPS AT 925 MB WILL BE 10C COLDER WITH VALUES TUESDAY
AT -12C TO -14C. FULLY MIXED THIS WOULD SUPPORT MAX TEMPS IN THE
20S. DEWPOINTS WILL DIVE TO THE SINGLE NUMBERS AND BELOW ZERO. THIS
WILL MAKE ROOM FOR NIGHTTIME MIN TEMPS IN THE SINGLE NUMBERS AND
LOWER TEENS.
&&
.AVIATION /12Z THURSDAY THROUGH MONDAY/...
FORECASTER CONFIDENCE LEVELS...
LOW...LESS THAN 30 PERCENT.
MODERATE...30 TO 60 PERCENT.
HIGH...GREATER THAN 60 PERCENT.
NEAR TERM /THROUGH FRIDAY/...HIGH CONFIDENCE.
7 AM UPDATE...
VARIABLE CIGS BUT WITH AREAS OF 1500-2000 FEET IN THE NORTH AND
3000-3500 FEET IN THE SOUTH. IFR CIGS IN THE HILLS SUCH AS AT
ORH. EXPECT CONTINUED MVFR CIGS AND AREAS OF IFR VSBYS IN SNOW
LATER THIS MORNING/EARLY AFTERNOON. SNOW CHANGES TO RAIN IN RI AND
SOUTHEAST MASS.
IMPROVEMENT BEGINS TOWARDS EVENING AS WINDS REVERT WESTERLY AND
BECOME BLUSTERY...GUSTS DEVELOPING OVERNIGHT INTO FRIDAY THE
STRONGEST OF WHICH WILL LIKELY IMPACT SHORELINE TERMINALS. LOW- TO
MID-LEVEL CLOUDS FEW-SCT WILL LIKELY FILTER ACROSS THE TERMINALS.
KBOS TAF...HIGH CONFIDENCE IN TAF. LOWER CONFIDENCE WITH EXACT
TIMING OF IMPACTS. INITIAL SNOW ACCUMS OF AROUND A TENTH OR TWO IN
THE MORNING WILL WASH AWAY AS SNOW MIXES OVER TO RAIN DURING THE
MORNING HOURS.
KBDL TAF...HIGH CONFIDENCE IN TAF. MUCH OF THE ACTIVITY STAYS EAST
OF THE TERMINAL. EXPECTING JUST SOME FLURRIES TO A BRIEF LIGHT
SNOW SHOWER THAT WILL YIELD AROUND A TRACE OF SNOW ACCUM AT MOST.
OUTLOOK...FRIDAY NIGHT THROUGH MONDAY
FRIDAY NIGHT THROUGH SUNDAY MORNING...HIGH CONFIDENCE. VFR.
SUNDAY AFTERNOON THROUGH MONDAY...MODERATE CONFIDENCE. CIGS AND
VSBYS WILL LOWER TO MVFR IN DEVELOPING RAIN SUNDAY AFTERNOON AND
EVENING. PRECIPITATION MAY MIX WITH SNOW OR BECOME ALL SNOW IN
SOUTHERN NH AND PARTS OF NORTHERN MASS. IFR CONDITIONS POSSIBLE
SUNDAY NIGHT. PRECIPITATION ENDS BY MONDAY MORNING AND CONDITIONS
WILL IMPROVE TO VFR.
&&
.MARINE...
FORECASTER CONFIDENCE LEVELS...
LOW...LESS THAN 30 PERCENT.
MODERATE...30 TO 60 PERCENT.
HIGH...GREATER THAN 60 PERCENT.
NEAR TERM /THROUGH FRIDAY/...HIGH CONFIDENCE.
WILL SEE AN ENHANCEMENT OF FLOW AS AN AREA OF LOW PRES DEVELOPS S
OF NEW ENGLAND MIDDAY AND LIFTS NE INTO THE GULF OF MAINE BY
EVENING...GROWING STRONGER THROUGH ITS TRACK. WINDS VEERING E/SE
GRADUALLY TO S DURING THE DAY WILL AMPLIFY IN RESPONSE. SEAS
LIKELY TO BUILD TO 5 FEET OR GREATER BY MIDDAY...THUS SMALL-CRAFT
ADVISORIES ARE IN EFFECT.
ATTENDANT MIX OF RAIN AND SNOW INITIALLY CHANGING OVER TO ALL
RAIN THROUGH THE MORNING MAY YIELD VISIBILITY IMPACTS OVER THE
WATERS.
OVERNIGHT...COVERAGE OF SMALL-CRAFT ADVISORIES EXTENDS IN RESPONSE
TO WINDS BACKING OUT OF THE WEST BEHIND THE DEPARTING SYSTEM AND
BECOMING BLUSTERY WITH GUSTS UP TO 25 KTS. CONDITIONS CONTINUE
THROUGH FRIDAY. SEAS BUILDING OVER THE OUTER WATERS...5 TO 7 FEET.
OUTLOOK...FRIDAY NIGHT THROUGH MONDAY
MODERATE CONFIDENCE
FRIDAY NIGHT-SATURDAY...WEST TO SOUTHWEST WINDS MAY GUST NEAR 25
KNOTS. SEAS WILL SUBSIDE BELOW 5 FEET FRIDAY NIGHT...BUT THEN BUILD
ON SATURDAY TO 5-7 FEET ESPECIALLY ON THE OUTER WATERS. A SMALL
CRAFT ADVISORY MAY BE NEEDED FOR PARTS OF THE MASS AND RI WATERS.
SUNDAY...COASTAL LOW PRESSURE MOVES UP THE EAST COAST. VARIABLE
WINDS WILL BECOME NORTHEAST LATE SUNDAY AND THEN NORTHWEST MONDAY.
SPEEDS WILL BE AROUND 25 KNOTS...WHILE THE EXPOSED WATERS WILL SEE
SEAS BUILD TO 5 TO 7 FEET. SMALL CRAFT ADVISORY MAY BE NEEDED FOR
PARTS OF THE MASS AND RI WATERS.
&&
.BOX WATCHES/WARNINGS/ADVISORIES...
CT...NONE.
MA...NONE.
NH...NONE.
RI...NONE.
MARINE...SMALL CRAFT ADVISORY FROM 6 PM THIS EVENING TO 2 AM EST FRIDAY
FOR ANZ231-232-251.
SMALL CRAFT ADVISORY FROM 6 PM THIS EVENING TO MIDNIGHT EST
TONIGHT FOR ANZ233-234.
SMALL CRAFT ADVISORY FROM 4 PM THIS AFTERNOON TO 2 AM EST
FRIDAY FOR ANZ235-237.
SMALL CRAFT ADVISORY FROM 1 PM THIS AFTERNOON TO 7 PM EST
FRIDAY FOR ANZ250-254>256.
&&
$$
SYNOPSIS...WTB/SIPPRELL
NEAR TERM...WTB/SIPPRELL
SHORT TERM...SIPPRELL
LONG TERM...WTB
AVIATION...WTB/SIPPRELL
MARINE...WTB/SIPPRELL
AREA FORECAST DISCUSSION
NWS TAUNTON MA
322 AM EST THU DEC 26 2013
.SYNOPSIS...
A WEAK AND QUICK DISTURBANCE WILL BRING A MIX OF RAIN AND SNOW FOR
THE REGION TODAY. WHILE COOL FOR FRIDAY...MILDER CONDITIONS MOVE
IN FOR THE WEEKEND. LOW PRESSURE WILL MOVE NORTHEAST FROM THE
GULF OF MEXICO WILL PASS NEAR NANTUCKET SUNDAY NIGHT...THEN MOVE
SOUTH OF NOVA SCOTIA MONDAY MORNING. FRIGID AIR WILL INVADE THE
REGION BY TUESDAY.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
STRONGER NORTHERN STREAM IMPULSE THROUGH THE BROADER TROUGH REGIME
INVOKES A WEAK AREA OF LOW PRES SOUTH AND OFFSHORE OF NEW ENGLAND
WITHIN THE BETTER BAROCLINIC ZONE BY MIDDAY...QUICKLY MOVING
NORTHEASTWARD AND AMPLIFYING ACROSS THE GULF OF MAINE BY EVENING.
DURING THIS AMPLIFICATION...ATTENDANT DYNAMICS AND JET STREAK
ENHANCE SOUTH-SOUTHWESTERLY LOW- TO MID-LEVEL FLOW RESULTING IN
LOCALIZED MOISTURE CONVERGENCE ALONG THE LEADING WARM-FRONT /N-NE
QUADRANT OF THE SURFACE LOW/ WHERE FRONTOGENESIS/ISENTROPIC FORCING
IS MAXIMIZED.
ALREADY THIS MORNING...RADAR ECHOES ARE BUILDING ACROSS UPSTATE NY
OUT AHEAD OF THE NORTHERN STREAM IMPULSE...WHILE PER SATELLITE
TRENDS...LOW CLOUDS AND MOISTURE ARE BEING DRAWN UP FROM THE SOUTH.
SO WITH CERTAINTY...THE HEAVIEST OF PRECIP IMPACTS E/SE PORTIONS OF
SOUTHERN NEW ENGLAND WITH ONE TO TWO TENTHS /THE GREATEST OF WHICH
WILL BE ACROSS THE EASTERN CAPE AND NANTUCKET/. LESSER AMOUNTS
EXPECTED FOR THE NORTH AND WEST INTERIOR. CLOUDS ON THE INCREASE
SOUTH AND WEST PRESENTLY WILL BEGIN TO CLEAR OUT LATE.
BUT SOME QUESTION AS TO HOW QUICKLY ARCTIC AIR WILL SCOUR OUT. NOT A
ROBUST SYSTEM AND ONSHORE SOUTHERLY FLOW WILL BE LIGHT. WHILE MILDER
AIR WILL WORK IN SOUTH TO NORTH...CONSIDERING HOW LONG WE HAVE BEEN
IN AN ARCTIC GRIP...FEEL THE PROGRESSION OF MILDER AIR WILL BE SLOW
AGAINST THE ARCTIC AIRMASS. SUSPECT COASTAL LOCATIONS AND ADJACENT
PLAINS WILL WARM ABOVE FREEZING...WHILE INTERIOR LOCALES /ESPECIALLY
THOSE WITH A REMAINING SNOWPACK/ WILL STAY AT OR BELOW FREEZING
THROUGHOUT THE EVENT. WHILE THE HRRR MAY BE TOO COLD...THE WRF-ARW
2M TEMPS ARE A GOOD APPROXIMATION AS TO THINKING.
IN THE END...SNOW IS EXPECTED INITIALLY MIXING OVER TO RAIN FOR
COASTAL COMMUNITIES AND ADJACENT PLAINS...WITH MAINLY ALL SNOW FOR
THE NORTHERN AND WESTERN INTERIOR /NORTH AND WEST OF I-84 TO I-90 TO
I-95 AS AN APPROXIMATION/. ROUGHLY 1 TO 2 INCHES FOR THE HIGHER
TERRAIN OF THE BERKSHIRES/WORCESTER HILLS/MONADNOCKS...WITH A TRACE
TO AN INCH ELSEWHERE EXCEPT COASTAL COMMUNITIES. FOR AREAS MIXING
OVER TO RAIN...INITIAL SNOW ACCUMS WILL ALL BUT WASH AWAY.
A FINAL AND IMPORTANT NOTE...FORECAST GUIDANCE ALL BUT AGREES ON
SOME DRYING WITHIN THE BETTER SNOW GROWTH REGION ROUGHLY FOR AREAS
ALONG AND SOUTH OF THE MASS-PIKE BETWEEN NOW UNTIL 10 AM. HAVE
HINTED AT LIGHT FREEZING DRIZZLE MIXING IN WITH LIGHT SNOW.
HIGHS TODAY AROUND THE UPPER-20S TO LOW-30S /WARMEST CONDITIONS
ALONG THE IMMEDIATE SHORES...CAPE AND ISLANDS/.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH 6 PM FRIDAY/...
TONIGHT....
HIGH PRES AND COLDER AIR WORKING IN. WHILE THE SYSTEM CLEARS OUT...
WILL SEE SOME LOW- TO MID-LEVEL CLOUDS LINGER ASSOCIATED WITH FETCH
OFF THE LAKES AND ADDITIONAL WEAK IMPULSES ROUNDING THE BROADER FLOW
REGIME ALOFT. COLD AIR ADVECTION THROUGH THE LOW-LEVELS ALLOWS FOR
STEEPENING LAPSE RATES. MIX-DOWN OF FASTER MOMENTUM CERTAINLY
POSSIBLE WITH GUSTS OF 20 TO 25 MPH...ESPECIALLY ALONG THE SOUTH-
SOUTHEAST COAST WITH ADJACENT WARMER WATERS. NOT ARCTIC COLD...LOWS
AROUND THE UPPER-TEENS TO LOW-20S /WARMER ALONG IMMEDIATE SHORES/.
FRIDAY...
HIGH PRES CONTINUING TO BUILD...SHIFTING SOUTH AND EAST. WILL SEE
WESTERLY FLOW DIMINISH TURNING SOUTHWESTERLY...BECOMING LIGHT.
LINGERING LOW- TO MID-LEVEL CLOUDS WITH FETCH OFF THE LAKES. STILL
COLD WITH H925 TEMPS AROUND -4 TO -6C /H85 AROUND -10C/. HIGHS
AROUND THE LOW- TO MID-30S ANTICIPATED.
&&
.LONG TERM /FRIDAY NIGHT THROUGH WEDNESDAY/...
BIG PICTURE... UPPER LOW CENTERED OVER BAFFIN ISLAND/HUDSON BAY WITH
CYCLONIC FLOW OVER THE NORTHEAST USA WEAKENING EARLY IN THE
FORECAST...THEN STRENGTHENING AGAIN BY NEW YEARS EVE. THIS
CONTINUES TO FAVOR MODERATING TEMPS OVER THE WEEKEND...THEN A RETURN
TO BELOW NORMAL TEMPS EARLY NEXT WEEK. THE MAIN CHANGE IN THIS
PATTERN SEEMS TO BE A 24-HOUR DELAY IN THE ONSET OF NEXT WEEK/S
CHILL. THE UPPER JET AND SOUTHWEST FLOW DON/T MOVE EAST OF NEW
ENGLAND UNTIL MONDAY NIGHT.
MEANWHILE THE NORTHERN AND SOUTHERN UPPER JETS ARE NOW FORECAST TO
PHASE DURING SUNDAY...ALLOWING SOUTHERN STREAM SHORTWAVE TO TAP A
MORE PRONOUNCED BAROCLINIC ZONE AS IT MOVES PAST NEW ENGLAND. THE
PHASING SUGGESTS DEEPENING OF THE UPPER TROUGH TO OUR WEST RESULTING
IN MORE OF A SOUTHWEST FLOW ALOFT. THIS LEAVES ROOM FOR THE SURFACE
COASTAL LOW TO EDGE CLOSER TO THE COAST LATER SUNDAY/SUNDAY NIGHT.
THIS IS A STORMIER SCENARIO FOR US THAN WAS DEPICTED 24 HOURS AGO.
WE WILL NEED TO MONITOR THAT THIS SUDDEN CHANGE DOESN/T GO BACK THE
OTHER WAY JUST AS FAST.
MODELS... GFS AND ECMWF ARE SIMILAR WITH THEIR SURFACE ISOBARS/UPPER
CONTOURS/UPPER JET WIND SPEEDS THROUGH SUNDAY NIGHT. SMALL
DIFFERENCES DEVELOP MONDAY THROUGH WEDNESDAY. WE FAVOR A BLEND OF
THE LONG RANGE GUIDENCE.
THE DAILIES...
FRIDAY NIGHT-SATURDAY... COLD NORTHWEST FLOW FLATTENS TO A WEST-EAST
FLOW AS SHORTWAVES IN THE NORTHERN AND SOUTHERN STREAMS MOVE INTO
THE PLAINS. THE NORTHERN STREAM SUPPORTS A STALLED COLD FRONT ALONG
THE CANADIAN BORDER WITH LOW PRESSURE WAVES RIPPLING ALONG IT.
MEANWHILE HIGH PRESSURE IS IN PLACE ACROSS THE SOUTHEAST AND MID
ATLANTIC STATES. LIGHT FLOW AND DRY AIR WILL ALLOW FRIDAY NIGHT
TEMPS TO DIP INTO THE TEENS AND 20S. THEN THE MILDER AIR WILL START
FLOWING IN A WEST-SOUTHWEST FLOW. CLOUDS ASSOCIATED WITH THE
STALLED COLD FRONT WILL AFFECT NORTHERN NEW ENGLAND SATURDAY AND MAY
BRING PARTLY CLOUDY SKIES TO PARTS OF OUR AREA. BUT OVERALL IT WILL
BE A FAIR DAY WITH TEMPS REACHING THE UPPER 30S AND 40S.
SUNDAY-MONDAY... SOUTHERN STREAM LOW PRESSURE DEVELOPS OVER THE GULF
OF MEXICO LATE SATURDAY AND MOVES UP THE EAST COAST ON SUNDAY. AS
NOTED ABOVE...THE TWO JET STREAMS ARE NOW EXPECTED TO PHASE ON
SUNDAY ALLOWING THE COASTAL SYSTEM TO MOVE CLOSER TO THE COAST. IF
THIS VERIFIES...IT WILL ALLOW PRECIPITATION TO REACH MOST OR ALL OF
OUR AREA LATER SUNDAY AND SUNDAY NIGHT. TEMPS IN THE VERTICAL WILL
BE ABOVE FREEZING SOUTH OF THE MASS PIKE WHILE AREAS FARTHER NORTH
MAY HAVE TEMPS EITHER SIDE OF FREEZING. THIS WILL MEAN RAIN FOR OUR
SOUTHERN AREAS AND A RAIN/SNOW MIX IN THE NORTH...POSSIBLY ALL SNOW
IN SOUTHERN NH. THE CURRENT MODEL INFORMATION IS NOTICEABLY
DIFFERENT FROM THE INFO 24 HOURS AGO SO CONFIDENCE IS VERY LIMITED
FOR THIS FORECAST. ALSO SMALL CHANGES IN THE FLOW OVER THE NEXT 3-4
DAYS COULD PUSH THE RAIN TEMPERATURES FARTHER NORTH OR THE SNOW
TEMPERATURES FARTHER SOUTH. SO STAY TUNED. THE UPPER FLOW WILL
REMAIN OPEN TO THE EAST ALLOWING THE COASTAL STORM TO RACE OFF
THROUGH THE MARITIMES SUNDAY NIGHT. MONDAY LOOKS SUNNIER/DRIER AND
COOLER...BUT NOT UNSEASONABLY SO.
TUESDAY-WEDNESDAY... WITH THE UPPER JET MOVING OFFSHORE MONDAY
NIGHT...THE WAY WILL BE OPEN FOR ARCTIC AIR TO RETURN TO SOUTHERN
NEW ENGLAND. TEMPS AT 925 MB WILL BE 10C COLDER WITH VALUES TUESDAY
AT -12C TO -14C. FULLY MIXED THIS WOULD SUPPORT MAX TEMPS IN THE
20S. DEWPOINTS WILL DIVE TO THE SINGLE NUMBERS AND BELOW ZERO. THIS
WILL MAKE ROOM FOR NIGHTTIME MIN TEMPS IN THE SINGLE NUMBERS AND
LOWER TEENS.
&&
.AVIATION /08Z THURSDAY THROUGH MONDAY/...
FORECASTER CONFIDENCE LEVELS...
LOW...LESS THAN 30 PERCENT.
MODERATE...30 TO 60 PERCENT.
HIGH...GREATER THAN 60 PERCENT.
NEAR TERM /THROUGH FRIDAY/...HIGH CONFIDENCE.
9Z UPDATE...
MVFR CIGS FILTING ONSHORE AS WINDS ARE GRADUALLY VEERING E/SE TO S
LATER TODAY. THROUGH THE MORNING AND INTO MIDDAY...CONDITIONS
EXPECTED TO DETERIORATE TO MVFR/IFR...HOLDING THROUGH AFTERNOON.
WITH ANY -SN SUGGEST MVFR/IFR CIGS WITH IFR VSBYS...BETTER CHANCES
FOR IFR CIGS WILL BE SOUTH AND EAST. WITH ANY -RA...EXPECT GREATER
CHANCES FOR IFR CIGS...YET WITH MVFR VSBYS.
IMPROVEMENT BEGINS TOWARDS EVENING AS WINDS REVERT WESTERLY AND
BECOME BLUSTERY...GUSTS DEVELOPING OVERNIGHT INTO FRIDAY THE
STRONGEST OF WHICH WILL LIKELY IMPACT SHORELINE TERMINALS. LOW- TO
MID-LEVEL CLOUDS FEW-SCT WILL LIKELY FILTER ACROSS THE TERMINALS.
KBOS TAF...HIGH CONFIDENCE IN TAF. LOWER CONFIDENCE WITH EXACT
TIMING OF IMPACTS. INITIAL SNOW ACCUMS OF AROUND A TENTH OR TWO IN
THE MORNING WILL WASH AWAY AS SNOW MIXES OVER TO RAIN DURING THE
MORNING HOURS.
MAINLY VFR...BUT MVFR CIGS HOLDING OVER THE CAPE AND ISLANDS. BY
MORNING MOST TERMINALS WILL BEGIN TO DETERIORATE MVFR/IFR WITH
ONSET OF A RAIN/SNOW MIX. EXPECT MORE IFR CONDITIONS DUE TO VSBY
WITH -SN /BEST CHANCES OVER N-W INTERIOR TERMINALS WHEREAS RAIN IS
EXPECTED ELSEWHERE...LITTLE ACTIVITY FOR TERMINALS IN THE S CT
VALLEY/. IFR CIGS EXPECTED MORESO FOR E/SE TERMINALS.
WILL SEE PRESENT LIGHT N WINDS VEER S/SE THROUGH THURSDAY...
BACKING OUT OF THE WEST WITH PASSAGE OF DISTURBED WEATHER BY WHICH
TIME CONDITIONS IMPROVE BACK TO VFR. WEST WINDS WILL BE GUSTY AT
TIMES AROUND 25 KTS.
KBDL TAF...HIGH CONFIDENCE IN TAF. MUCH OF THE ACTIVITY STAYS EAST
OF THE TERMINAL. EXPECTING JUST SOME FLURRIES TO A BRIEF LIGHT
SNOW SHOWER THAT WILL YIELD AROUND A TRACE OF SNOW ACCUM AT MOST.
OUTLOOK...FRIDAY NIGHT THROUGH MONDAY
FRIDAY NIGHT THROUGH SUNDAY MORNING...HIGH CONFIDENCE. VFR.
SUNDAY AFTERNOON THROUGH MONDAY...MODERATE CONFIDENCE. CIGS AND
VSBYS WILL LOWER TO MVFR IN DEVELOPING RAIN SUNDAY AFTERNOON AND
EVENING. PRECIPITATION MAY MIX WITH SNOW OR BECOME ALL SNOW IN
SOUTHERN NH AND PARTS OF NORTHERN MASS. IFR CONDITIONS POSSIBLE
SUNDAY NIGHT. PRECIPITATION ENDS BY MONDAY MORNING AND CONDITIONS
WILL IMPROVE TO VFR.
&&
.MARINE...
FORECASTER CONFIDENCE LEVELS...
LOW...LESS THAN 30 PERCENT.
MODERATE...30 TO 60 PERCENT.
HIGH...GREATER THAN 60 PERCENT.
NEAR TERM /THROUGH FRIDAY/...HIGH CONFIDENCE.
WILL SEE AN ENHANCEMENT OF FLOW AS AN AREA OF LOW PRES DEVELOPS S
OF NEW ENGLAND MIDDAY AND LIFTS NE INTO THE GULF OF MAINE BY
EVENING...GROWING STRONGER THROUGH ITS TRACK. WINDS VEERING E/SE
GRADUALLY TO S DURING THE DAY WILL AMPLIFY IN RESPONSE. SEAS
LIKELY TO BUILD TO 5 FEET OR GREATER BY MIDDAY...THUS SMALL-CRAFT
ADVISORIES ARE IN EFFECT.
ATTENDANT MIX OF RAIN AND SNOW INITIALLY CHANGING OVER TO ALL
RAIN THROUGH THE MORNING MAY YIELD VISIBILITY IMPACTS OVER THE
WATERS.
OVERNIGHT...COVERAGE OF SMALL-CRAFT ADVISORIES EXTENDS IN RESPONSE
TO WINDS BACKING OUT OF THE WEST BEHIND THE DEPARTING SYSTEM AND
BECOMING BLUSTERY WITH GUSTS UP TO 25 KTS. CONDITIONS CONTINUE
THROUGH FRIDAY. SEAS BUILDING OVER THE OUTER WATERS...5 TO 7 FEET.
OUTLOOK...FRIDAY NIGHT THROUGH MONDAY
MODERATE CONFIDENCE
FRIDAY NIGHT-SATURDAY...WEST TO SOUTHWEST WINDS MAY GUST NEAR 25
KNOTS. SEAS WILL SUBSIDE BELOW 5 FEET FRIDAY NIGHT...BUT THEN BUILD
ON SATURDAY TO 5-7 FEET ESPECIALLY ON THE OUTER WATERS. A SMALL
CRAFT ADVISORY MAY BE NEEDED FOR PARTS OF THE MASS AND RI WATERS.
SUNDAY...COASTAL LOW PRESSURE MOVES UP THE EAST COAST. VARIABLE
WINDS WILL BECOME NORTHEAST LATE SUNDAY AND THEN NORTHWEST MONDAY.
SPEEDS WILL BE AROUND 25 KNOTS...WHILE THE EXPOSED WATERS WILL SEE
SEAS BUILD TO 5 TO 7 FEET. SMALL CRAFT ADVISORY MAY BE NEEDED FOR
PARTS OF THE MASS AND RI WATERS.
&&
.BOX WATCHES/WARNINGS/ADVISORIES...
CT...NONE.
MA...NONE.
NH...NONE.
RI...NONE.
MARINE...SMALL CRAFT ADVISORY FROM 6 PM THIS EVENING TO 2 AM EST FRIDAY
FOR ANZ231-232-251.
SMALL CRAFT ADVISORY FROM 6 PM THIS EVENING TO MIDNIGHT EST
TONIGHT FOR ANZ233-234.
SMALL CRAFT ADVISORY FROM 4 PM THIS AFTERNOON TO 2 AM EST
FRIDAY FOR ANZ235-237.
SMALL CRAFT ADVISORY FROM 1 PM THIS AFTERNOON TO 7 PM EST
FRIDAY FOR ANZ250-254>256.
&&
$$
SYNOPSIS...WTB/SIPPRELL
NEAR TERM...SIPPRELL
SHORT TERM...SIPPRELL
LONG TERM...WTB
AVIATION...WTB/SIPPRELL
MARINE...WTB/SIPPRELL
AREA FORECAST DISCUSSION
NWS TAUNTON MA
315 AM EST THU DEC 26 2013
.SYNOPSIS...
A WEAK AND QUICK DISTURBANCE WILL BRING A MIX OF RAIN AND SNOW FOR
THE REGION TODAY. WHILE COOL FOR FRIDAY...MILDER CONDITIONS MOVE
IN FOR THE WEEKEND. LOW PRESSURE WILL MOVE NORTHEAST FROM THE
GULF OF MEXICO AND INTENSIFY NEAR NANTUCKET SUNDAY NIGHT...THEN
SOUTH OF NOVA SCOTIA MONDAY MORNING. FRIGID AIR WILL INVADE THE
REGION MONDAY AND TUESDAY. LOW PRESSURE TO OUR WEST COULD POSSIBLY
LEAD TO LIGHT SNOW AROUND NEW YEARS DAY.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
STRONGER NORTHERN STREAM IMPULSE THROUGH THE BROADER TROUGH REGIME
INVOKES A WEAK AREA OF LOW PRES SOUTH AND OFFSHORE OF NEW ENGLAND
WITHIN THE BETTER BAROCLINIC ZONE BY MIDDAY...QUICKLY MOVING
NORTHEASTWARD AND AMPLIFYING ACROSS THE GULF OF MAINE BY EVENING.
DURING THIS AMPLIFICATION...ATTENDANT DYNAMICS AND JET STREAK
ENHANCE SOUTH-SOUTHWESTERLY LOW- TO MID-LEVEL FLOW RESULTING IN
LOCALIZED MOISTURE CONVERGENCE ALONG THE LEADING WARM-FRONT /N-NE
QUADRANT OF THE SURFACE LOW/ WHERE FRONTOGENESIS/ISENTROPIC FORCING
IS MAXIMIZED.
ALREADY THIS MORNING...RADAR ECHOES ARE BUILDING ACROSS UPSTATE NY
OUT AHEAD OF THE NORTHERN STREAM IMPULSE...WHILE PER SATELLITE
TRENDS...LOW CLOUDS AND MOISTURE ARE BEING DRAWN UP FROM THE SOUTH.
SO WITH CERTAINTY...THE HEAVIEST OF PRECIP IMPACTS E/SE PORTIONS OF
SOUTHERN NEW ENGLAND WITH ONE TO TWO TENTHS /THE GREATEST OF WHICH
WILL BE ACROSS THE EASTERN CAPE AND NANTUCKET/. LESSER AMOUNTS
EXPECTED FOR THE NORTH AND WEST INTERIOR. CLOUDS ON THE INCREASE
SOUTH AND WEST PRESENTLY WILL BEGIN TO CLEAR OUT LATE.
BUT SOME QUESTION AS TO HOW QUICKLY ARCTIC AIR WILL SCOUR OUT. NOT A
ROBUST SYSTEM AND ONSHORE SOUTHERLY FLOW WILL BE LIGHT. WHILE MILDER
AIR WILL WORK IN SOUTH TO NORTH...CONSIDERING HOW LONG WE HAVE BEEN
IN AN ARCTIC GRIP...FEEL THE PROGRESSION OF MILDER AIR WILL BE SLOW
AGAINST THE ARCTIC AIRMASS. SUSPECT COASTAL LOCATIONS AND ADJACENT
PLAINS WILL WARM ABOVE FREEZING...WHILE INTERIOR LOCALES /ESPECIALLY
THOSE WITH A REMAINING SNOWPACK/ WILL STAY AT OR BELOW FREEZING
THROUGHOUT THE EVENT. WHILE THE HRRR MAY BE TOO COLD...THE WRF-ARW
2M TEMPS ARE A GOOD APPROXIMATION AS TO THINKING.
IN THE END...SNOW IS EXPECTED INITIALLY MIXING OVER TO RAIN FOR
COASTAL COMMUNITIES AND ADJACENT PLAINS...WITH MAINLY ALL SNOW FOR
THE NORTHERN AND WESTERN INTERIOR /NORTH AND WEST OF I-84 TO I-90 TO
I-95 AS AN APPROXIMATION/. ROUGHLY 1 TO 2 INCHES FOR THE HIGHER
TERRAIN OF THE BERKSHIRES/WORCESTER HILLS/MONADNOCKS...WITH A TRACE
TO AN INCH ELSEWHERE EXCEPT COASTAL COMMUNITIES. FOR AREAS MIXING
OVER TO RAIN...INITIAL SNOW ACCUMS WILL ALL BUT WASH AWAY.
A FINAL AND IMPORTANT NOTE...FORECAST GUIDANCE ALL BUT AGREES ON
SOME DRYING WITHIN THE BETTER SNOW GROWTH REGION ROUGHLY FOR AREAS
ALONG AND SOUTH OF THE MASS-PIKE BETWEEN NOW UNTIL 10 AM. HAVE
HINTED AT LIGHT FREEZING DRIZZLE MIXING IN WITH LIGHT SNOW.
HIGHS TODAY AROUND THE UPPER-20S TO LOW-30S /WARMEST CONDITIONS
ALONG THE IMMEDIATE SHORES...CAPE AND ISLANDS/.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH 6 PM FRIDAY/...
TONIGHT....
HIGH PRES AND COLDER AIR WORKING IN. WHILE THE SYSTEM CLEARS OUT...
WILL SEE SOME LOW- TO MID-LEVEL CLOUDS LINGER ASSOCIATED WITH FETCH
OFF THE LAKES AND ADDITIONAL WEAK IMPULSES ROUNDING THE BROADER FLOW
REGIME ALOFT. COLD AIR ADVECTION THROUGH THE LOW-LEVELS ALLOWS FOR
STEEPENING LAPSE RATES. MIX-DOWN OF FASTER MOMENTUM CERTAINLY
POSSIBLE WITH GUSTS OF 20 TO 25 MPH...ESPECIALLY ALONG THE SOUTH-
SOUTHEAST COAST WITH ADJACENT WARMER WATERS. NOT ARCTIC COLD...LOWS
AROUND THE UPPER-TEENS TO LOW-20S /WARMER ALONG IMMEDIATE SHORES/.
FRIDAY...
HIGH PRES CONTINUING TO BUILD...SHIFTING SOUTH AND EAST. WILL SEE
WESTERLY FLOW DIMINISH TURNING SOUTHWESTERLY...BECOMING LIGHT.
LINGERING LOW- TO MID-LEVEL CLOUDS WITH FETCH OFF THE LAKES. STILL
COLD WITH H925 TEMPS AROUND -4 TO -6C /H85 AROUND -10C/. HIGHS
AROUND THE LOW- TO MID-30S ANTICIPATED.
&&
.LONG TERM /FRIDAY NIGHT THROUGH WEDNESDAY/...
THE BIG PICTURE...
LOOKS LIKE THREE MAIN WEATHER EVENTS FOR THE EXTENDED RANGE.
THESE INCLUDE A STORM SUNDAY NIGHT INTO EARLY MONDAY...A BLAST OF
COLD AIR MONDAY INTO TUESDAY...POSSIBLY SOME LIGHT SNOW NEW YEARS
DAY...
THE LONG TERM FORECAST PERIOD BEGINS FRIDAY WITH A STRONG UPPER LOW
OVER BAFFIN BAY CANADA AND BRISK NORTHWEST FLOW ALOFT OVER NEW
ENGLAND. THE FLOW SPLITS IN THE SOUTHERN PLAINS WITH A SEPARATE
UPPER LOW OVER OKLAHOMA/TEXAS. AT THE SURFACE...SPRAWLING HIGH
PRESSURE FROM THE SOUTHERN PLAINS TO THE MID ATLANTIC WILL PROVIDE
QUIET WEATHER WITH MODERATING TEMPERATURES TO SOUTHERN NEW ENGLAND
FRIDAY AND SATURDAY. THIS SOUTHERN STREAM UPPER LOW IS FORECAST TO
EJECT NORTHEASTWARD SPAWNING LOW PRESSURE IN THE GULF OF MEXICO THAT
INTENSIFIES SOUTHEAST OF NEW ENGLAND SUNDAY NIGHT. A COLD BLAST OF
ARCTIC AIR WILL FOLLOW ON BRISK NORTHWEST WINDS MONDAY. IT WILL
REMAIN COLD INTO MIDWEEK AT WHICH TIME LOW PRESSURE SYSTEM AND THE
WARM ADVECTION IN ADVANCE OF IT WILL MOVE FROM THE LOWER GREAT LAKES
TOWARD NORTHERN NEW ENGLAND...PERHAPS BRINGING SOME LIGHT SNOW.
IT SHOULD BE NOTED THAT INCREDIBLY WIDE FLUCTUATIONS IN MODEL
FORECASTS HAVE BEEN OCCURRING JUST BEYOND OUR CURRENT FORECAST
PERIOD...FOR THE END OF NEXT WEEK. THIS IS IMPORTANT BECAUSE
ASTRONOMICAL TIDES WILL BE VERY HIGH AND ANY STRONG WINDS COULD LEAD
TO THE POSSIBILITY OF COASTAL FLOODING. THE ATMOSPHERIC DYNAMICS ARE
FORECAST TO BE QUITE STRONG BY THE END OF NEXT WEEK. THE QUESTION IS
WHETHER A MASSIVE COLD OUTBREAK/UPPER LOW PRESSURE IN CANADA WILL
PLUNGE SOUTH INTO THE U.S. AND HOW FAR SOUTHWARD. FOR EXAMPLE THE
06Z GFS RUN WAS DRASTIC WITH COLD AIR PLUNGING TO THE DEEP SOUTH AND
SPINNING UP AN INTENSE STORM OVER NEW ENGLAND...NOW THE 12Z GFS RUN
KEEPS IT IN CANADA. THE 00Z ECMWF RUN REALLY WENT TO TOWN WITH
ARCTIC AIR INTO THE DEEP SOUTH AND A 190+ KNOT JET AT 300 MB
SPAWNING AN INTENSE NORTHEAST STORM. THE 12Z ECMWF STILL DEPICTS AN
INTENSE LOW BUT MORE FOR THE NORTHERN NEW ENGLAND/CANADIAN BORDER
WITH COLD AIR HEADED HERE AND NOT THE DEEP SOUTH. STAY TUNED.
THE DAILIES...
FRIDAY...
WITH STRONG HIGH PRESSURE TO OUR SOUTH...EXPECT PARTLY TO MOSTLY
SUNNY SKIES. WINDS WILL SHIFT FROM NORTHWEST TO SOUTHWEST. STILL
VERY COLD WITH 850 MB TEMPERATURES STILL -8C TO -10C. HIGHS IN THE
30S. LOWS FRIDAY NIGHT IN THE TEENS AND 20S.
SATURDAY...
HIGH PRESSURE SHIFTS OFF THE MID ATLANTIC COAST AND OUT TO SEA.
SOUTHWEST WINDS OVER SOUTHERN NEW ENGLAND HELP USHER MILDER AIR
INTO THE REGION. 850 MB TEMPERATURES WARM ALL THE WAY TO +4C TO
+6C BY SAT EVENING. HAVE GONE A FEW DEGREES ABOVE MODEL CONSENSUS
FOR AFTERNOON HIGHS...IN THE 40S EVERYWHERE. LOWS SATURDAY NIGHT
IN THE 20S TO MID 30S EXCEPT UPPER 30S ON THE ISLANDS.
SUNDAY AND SUNDAY NIGHT...
THE UPPER ENERGY FROM THE OK/TX LOW EJECTS NORTHEASTWARD. SURFACE
LOW PRESSURE IS FORECAST TO TRACK FROM THE GULF OF MEXICO UP THE
EASTERN SEABOARD...AND BEGIN TO INTENSIFY OVER THE BENCHMARK OF
40N/70W AND STRENGTHEN FURTHER AS IT QUICKLY MOVES OUT TO SEA
SOUTH OF NOVA SCOTIA BY DAYBREAK MONDAY. THE 12Z ECMWF MODEL IS
VERY INTENSE WITH THIS STORM AND HAS MUCH MORE MOISTURE ASSOCIATED
WITH IT THAN THE GFS AND CANADIAN MODELS. THE GFS IS QUICK...WITH
CLEARING ABOUT 6-12 HOURS SOONER THAN THE ECMWF. HAVE SIDED MORE
WITH THE SLOWER ECMWF WHICH HAS BEEN CONSISTENT WITH THIS FEATURE
OVER THE PAST FEW RUNS. HAVE USED ECMWF WINDS INSTEAD OF MODEL
CONSENSUS FOR THE PERIOD FROM 18Z SUNDAY TO 12Z MONDAY. THE GOOD
NEWS IS THAT MOST OF SUNDAY WILL BE DRY ALLOWING TEMPERATURES TO
WARM INTO THE 40S AGAIN. THE BEST CHANCES OF RAIN MOVE IN FROM
SOUTH TO NORTH LATE IN THE DAY OR EVENING.
THERMAL PROFILES ON THE ECMWF HOWEVER MAY PRESENT A PROBLEM AS THE
STORM PROGRESSES. LOW LEVEL THICKNESSES AND 850 MB TEMPERATURES MAY
COOL ENOUGH TO CHANGE RAIN OVER TO SNOW OR PERHAPS A BRIEF PERIOD OF
FREEZING RAIN IN THE WESTERN PORTIONS OF THE AREA...BUT THE HIGHEST
QPF IS IN THE EAST...WHERE IT WILL BE RAIN. NOT EXPECTING MUCH IF
ANY ACCUMULATION IN THE WEST...AND IF THE GFS IS RIGHT...IT WILL END
THERE BEFORE ANY CHANGEOVER.
MONDAY AND TUESDAY...
ARCTIC AIR BLASTS INTO THE REGION MONDAY AFTERNOON AND NIGHT...
WITH 850 MB TEMPERATURES DIVING TO -16C TO -18C MONDAY NIGHT...AND
CONTINUING DOWN TO -20C TO -22C TUESDAY. AM FORECASTING LOWS
MONDAY NIGHT IN THE SINGLE DIGITS IN SOUTHERN NH AND NORTHERN MA
AND TEENS ELSEWHERE EXCEPT LOWER 20S ON THE ISLANDS. BREEZY
CONDITIONS WILL MAKE IT FEEL EVEN COLDER. HIGHS ONLY IN THE 20S
TUESDAY. LOWS ON NEW YEARS EVE/TUESDAY NIGHT/ RANGING FROM 7
NORTHWEST TO 17 SOUTHEAST WITH LOWER 20S ON THE ISLANDS. THERE IS
A CHANCE...ESPECIALLY ON TUESDAY THAT THE OUTER CAPE COULD AGAIN
SEE OCEAN EFFECT SNOW SHOWERS...EVEN THOUGH THE SURFACE FLOW IS
NORTHWESTERLY.
WEDNESDAY/NEW YEARS DAY...
LOW CONFIDENCE AT THIS TIME. MODEL CONSENSUS IS THAT LOW PRESSURE
MOVES FROM THE GREAT LAKES TO NORTHERN NEW ENGLAND MIDWEEK. WARM
ADVECTION PRECIPITATION...DEFINITELY IN THE FORM OF SNOW...IS
POSSIBLE AHEAD OF THIS. IT WOULD BE ON THE LIGHT SIDE. BECAUSE OF
VERY DISPARATE MODEL SOLUTIONS WITH THIS AND THE EVOLVING DEEP
UPPER LOW BEHIND THIS STORM FOR LATE NEXT WEEK...HAVE OPTED TO
ONLY INCLUDE SLIGHT CHANCE PROBABILITIES FOR WED AT THIS POINT.
THIS MAY EVENTUALLY BE INCREASING AS TIME GETS CLOSER. NOT QUITE
AS COLD WED WITH HIGHS UPPER 20S TO MID 30S.
&&
.AVIATION /08Z THURSDAY THROUGH MONDAY/...
FORECASTER CONFIDENCE LEVELS...
LOW...LESS THAN 30 PERCENT.
MODERATE...30 TO 60 PERCENT.
HIGH...GREATER THAN 60 PERCENT.
NEAR TERM /THROUGH FRIDAY/...HIGH CONFIDENCE.
9Z UPDATE...
MVFR CIGS FILTING ONSHORE AS WINDS ARE GRADUALLY VEERING E/SE TO S
LATER TODAY. THROUGH THE MORNING AND INTO MIDDAY...CONDITIONS
EXPECTED TO DETERIORATE TO MVFR/IFR...HOLDING THROUGH AFTERNOON.
WITH ANY -SN SUGGEST MVFR/IFR CIGS WITH IFR VSBYS...BETTER CHANCES
FOR IFR CIGS WILL BE SOUTH AND EAST. WITH ANY -RA...EXPECT GREATER
CHANCES FOR IFR CIGS...YET WITH MVFR VSBYS.
IMPROVEMENT BEGINS TOWARDS EVENING AS WINDS REVERT WESTERLY AND
BECOME BLUSTERY...GUSTS DEVELOPING OVERNIGHT INTO FRIDAY THE
STRONGEST OF WHICH WILL LIKELY IMPACT SHORELINE TERMINALS. LOW- TO
MID-LEVEL CLOUDS FEW-SCT WILL LIKELY FILTER ACROSS THE TERMINALS.
KBOS TAF...HIGH CONFIDENCE IN TAF. LOWER CONFIDENCE WITH EXACT
TIMING OF IMPACTS. INITIAL SNOW ACCUMS OF AROUND A TENTH OR TWO IN
THE MORNING WILL WASH AWAY AS SNOW MIXES OVER TO RAIN DURING THE
MORNING HOURS.
MAINLY VFR...BUT MVFR CIGS HOLDING OVER THE CAPE AND ISLANDS. BY
MORNING MOST TERMINALS WILL BEGIN TO DETERIORATE MVFR/IFR WITH
ONSET OF A RAIN/SNOW MIX. EXPECT MORE IFR CONDITIONS DUE TO VSBY
WITH -SN /BEST CHANCES OVER N-W INTERIOR TERMINALS WHEREAS RAIN IS
EXPECTED ELSEWHERE...LITTLE ACTIVITY FOR TERMINALS IN THE S CT
VALLEY/. IFR CIGS EXPECTED MORESO FOR E/SE TERMINALS.
WILL SEE PRESENT LIGHT N WINDS VEER S/SE THROUGH THURSDAY...
BACKING OUT OF THE WEST WITH PASSAGE OF DISTURBED WEATHER BY WHICH
TIME CONDITIONS IMPROVE BACK TO VFR. WEST WINDS WILL BE GUSTY AT
TIMES AROUND 25 KTS.
KBDL TAF...HIGH CONFIDENCE IN TAF. MUCH OF THE ACTIVITY STAYS EAST
OF THE TERMINAL. EXPECTING JUST SOME FLURRIES TO A BRIEF LIGHT
SNOW SHOWER THAT WILL YIELD AROUND A TRACE OF SNOW ACCUM AT MOST.
OUTLOOK...FRIDAY THROUGH SUNDAY...
FRIDAY THROUGH SATURDAY...HIGH CONFIDENCE. VFR.
SUNDAY...MODERATE CONFIDENCE. VFR IN THE MORNING AND EARLY
AFTERNOON. MVFR CIGS MOVING IN FROM SOUTH TO NORTH LATE IN THE
AFTERNOON AND OVERSPREADING THE ENTIRE REGION BY EVENING. IFR
CONDITIONS POSSIBLE IN RAIN AND FOG...POSSIBLY CHANGING TO SNOW IN
THE WESTERN HALF OF THE REGION BEFORE ENDING BY DAYBREAK MONDAY.
&&
.MARINE...
FORECASTER CONFIDENCE LEVELS...
LOW...LESS THAN 30 PERCENT.
MODERATE...30 TO 60 PERCENT.
HIGH...GREATER THAN 60 PERCENT.
NEAR TERM /THROUGH FRIDAY/...HIGH CONFIDENCE.
WILL SEE AN ENHANCEMENT OF FLOW AS AN AREA OF LOW PRES DEVELOPS S
OF NEW ENGLAND MIDDAY AND LIFTS NE INTO THE GULF OF MAINE BY
EVENING...GROWING STRONGER THROUGH ITS TRACK. WINDS VEERING E/SE
GRADUALLY TO S DURING THE DAY WILL AMPLIFY IN RESPONSE. SEAS
LIKELY TO BUILD TO 5 FEET OR GREATER BY MIDDAY...THUS SMALL-CRAFT
ADVISORIES ARE IN EFFECT.
ATTENDANT MIX OF RAIN AND SNOW INITIALLY CHANGING OVER TO ALL
RAIN THROUGH THE MORNING MAY YIELD VISIBILITY IMPACTS OVER THE
WATERS.
OVERNIGHT...COVERAGE OF SMALL-CRAFT ADVISORIES EXTENDS IN RESPONSE
TO WINDS BACKING OUT OF THE WEST BEHIND THE DEPARTING SYSTEM AND
BECOMING BLUSTERY WITH GUSTS UP TO 25 KTS. CONDITIONS CONTINUE
THROUGH FRIDAY. SEAS BUILDING OVER THE OUTER WATERS...5 TO 7 FEET.
OUTLOOK...FRIDAY THROUGH SUNDAY...
MODERATE CONFIDENCE
FRI AND SAT...WEST-NORTHWEST WINDS MAY GUST TO 20 TO 25 KT FRI.
ON SAT...SOUTHWEST WINDS MAY GUST TO AROUND 20 KT. SEAS JUST BELOW
SCA CRITERIA OF 5 FT ON THE OUTER WATERS FRI-SAT. A SMALL CRAFT
ADVISORY MAY BE NEEDED FOR PARTS OF THE WATERS.
A STORM SYSTEM TRACKING UP THE COAST SUNDAY WILL INTENSIFY
SOUTHEAST OF NEW ENGLAND SUNDAY NIGHT AND HEAD TOWARD NOVA SCOTIA
EARLY MONDAY. SMALL CRAFT ADVISORIES WILL LIKELY BE NEEDED. WINDS
WILL BE DEPENDENT ON THE EXACT TRACK OF THE LOW BUT SHOULD SWING
TO THE NORTHEAST AT SOME POINT SUNDAY NIGHT AND MAY GUST TO 25-30
KT. SEAS MAY BUILD TO 6 TO 10 FT OVER THE OUTER
WATERS...ESPECIALLY THE SOUTHEASTERN WATERS.
&&
.BOX WATCHES/WARNINGS/ADVISORIES...
CT...NONE.
MA...NONE.
NH...NONE.
RI...NONE.
MARINE...SMALL CRAFT ADVISORY FROM 6 PM THIS EVENING TO 2 AM EST FRIDAY
FOR ANZ231-232-251.
SMALL CRAFT ADVISORY FROM 6 PM THIS EVENING TO MIDNIGHT EST
TONIGHT FOR ANZ233-234.
SMALL CRAFT ADVISORY FROM 4 PM THIS AFTERNOON TO 2 AM EST
FRIDAY FOR ANZ235-237.
SMALL CRAFT ADVISORY FROM 1 PM THIS AFTERNOON TO 7 PM EST
FRIDAY FOR ANZ250-254>256.
&&
$$
SYNOPSIS...SIPPRELL/GAF
NEAR TERM...SIPPRELL
SHORT TERM...SIPPRELL
LONG TERM...GAF
AVIATION...SIPPRELL/GAF
MARINE...SIPPRELL/GAF
AREA FORECAST DISCUSSION
NWS TAMPA BAY RUSKIN FL
745 PM EST FRI DEC 27 2013
.UPDATE (REST OF TONIGHT AND SATURDAY)...
00Z WATER VAPOR AND H4 RAP ANALYSIS SHOWS CONVERGENT MID/UPPER LEVEL
FLOW OVER THE EASTERN HALF OF THE NATION BETWEEN A WEAK TROUGH IN
THE NORTHERN STREAM OVER THE GREAT LAKES/NEW ENGLAND...AND THE
SOUTHERN STREAM RIDING NORTHWARD OUT OF THE GULF OF MEXICO AROUND A
LARGE TROUGH/CLOSED LOW SPINNING OVER THE SOUTHERN PLAINS. THE
EVENTUAL EJECTION EASTWARD OF THIS UPPER LEVEL ENERGY WILL BRING
HIGH CHANCES FOR SHOWERS BY SUNDAY...BUT UNTIL THEN...A MORE BENIGN
WEATHER PATTERN WILL BE IN PLACE FOR THE FIRST HALF OF YOUR UPCOMING
WEEKEND. WV IMAGERY SHOWS ABUNDANT UPPER LEVEL MOISTURE STREAMING
OVER OUR HEADS THIS EVENING...AND ANALYSIS OF THE 28/00Z KTBW
SOUNDING PROFILE SHOWS THAT THIS MOISTURE IS PRESENT THROUGH A GOOD
DEAL OF THE TROP COLUMN.
CLOSER TO THE SURFACE...FL PENINSULA RESIDES WITHIN EASTERLY FLOW ON
THE SOUTHERN PERIPHERY OF A LARGE 1030MB HIGH PRESSURE RIDGE. HAVE
SEEN SOME WEAK ISENTROPIC UPGLIDE THROUGH THE DAY ACROSS THE AREA
WHICH WAS JUST ENOUGH TO SUPPLY NORTHERN AND CENTRAL ZONES WITH A
FEW LIGHT SHOWERS/SPRINKLES. ALTHOUGH THE OVERALL LIFT HAS SUBSIDED
AND PUSHED NORTHWARD ALLOWING THE SHOWER COVERAGE TO
DIMINISH...THERE IS STILL JUST ENOUGH UPGLIDE PRESENT IN THE LOWER
LEVELS TO SUPPORT THE LOWER CLOUDS ALONG AND NORTH OF THE I-4
CORRIDOR. SOUTH OF THESE AREAS...LESS FAVORABLE LIFT AND MOISTURE
PROFILES ALLOWED THE CLOUDS TO BREAK.
FOR THE REST OF THE OVERNIGHT...LOOKING FOR MAINLY DRY
CONDITIONS...ALTHOUGH A FEW SPRINKLES CAN NOT BE RULED OUT FROM
TAMPA NORTHWARD WITHIN THE WEAK UPGLIDE REGIME. MORE LIKELY THAT WE
WILL JUST HOLD ONTO A LOWER CLOUD DECK OVER THESE ZONES.
TEMPERATURES WILL FALL MUCH THROUGH THE OVERNIGHT...WITH MID/UPPER
50S OVER LEVY COUNTY...TO THE LOWER AND MIDDLE 60S ELSEWHERE.
SATURDAY...SYNOPTIC PATTERN WILL BEGIN TO CHANGE AS THE TROUGH OVER
THE SOUTHERN PLAINS BEGINS TO BECOME MORE PROGRESSIVE. DCVA AND
ASSOCIATED HEIGHT FALLS EJECTING OVER THE WESTERN/CENTRAL GULF OF
MEXICO WILL FORCE SLOW CYCLOGENESIS AT THE SURFACE THAT WILL WORK
NORTHWARD TOWARD THE MS DELTA REGION. THESE HEIGHT FALLS TO OUR WEST
WILL ACTUALLY HELP TO RIDGE UP THE FLOW OVER THE FL PENINSULA AND
ALLOW FOR A DECENT DAY WEATHERWISE. THE MOST CLOUDS WILL BE TO THE
NORTH OF TAMPA IN CLOSER PROXIMITY TO AN ORGANIZING WARM
FRONT...WHILE CENTRAL AND SOUTHERN ZONES WILL ACTUALLY HAVE A SHOT
AT A MIX OF SUN AND CLOUDS. THE ATMOSPHERE WILL BE A BIT ON THE
UNSTABLE SIDE...AND THIS INSTABILITY ALONG WITH INCREASING UPGLIDE
FIELDS SHOULD BE ENOUGH TO FORCE A FEW SCATTERED SHOWERS.
HOWEVER...CURRENT THINKING IS THAT ANY SHOWERS WILL BE BRIEF AND
HAVE A VERY LIMITED IMPACT ON ANY OUTDOOR ACTIVITIES. GOOD DIURNAL
MIXING WITHIN AND A WARM POTENTIAL IN THE LOWER LEVELS WILL RESULT
IN WELL ABOVE NORMAL LATE DECEMBER DAY FOR TEMPERATURES WITH MANY
SPOTS REACHING THE LOWER 80S. "COOLER" TEMPS IN THE 70S WILL BE
FOUND FOR THE NORTHERN NATURE COAST ZONES WHERE THE CLOUDS SHOULD
BE MORE ABUNDANT. HAVE A GREAT NIGHT AND A PLEASANT SATURDAY!
&&
.MARINE...
THE EASTERN GULF OF MEXICO WILL LIE BETWEEN HIGH PRESSURE TO THE
NORTHEAST AND A DEVELOPING TROUGH OF LOW PRESSURE OVER THE CENTRAL
GULF THROUGH SATURDAY MORNING. EASTERLY FLOW TO CAUTIONARY LEVELS
WILL BE COMMON THROUGH SATURDAY MORNING AND THEN DIMINISH BELOW
HEADLINE CRITERIA SATURDAY AFTERNOON. WINDS WILL AGAIN INCREASE FROM
THE SOUTH SATURDAY NIGHT AHEAD OF AN APPROACHING COLD FRONT THAT
WILL CROSS THROUGH THE FORECAST WATERS DURING SUNDAY. WINDS WILL
SHIFT TO THE NORTHWEST AND NORTH IN THE WAKE OF THIS FRONT.
&&
.AVIATION...
28/00Z-29/00Z...PREVAILING BKN-OVC CLOUDS. TEMPO IFR/MVFR FROM LATE
NIGHT UNTIL SHORTLY AFTER SUNRISE...MAINLY LOW CIGS BUT SOME 6-3SM
IN BR. LAL AND PGD ARE EXPECTED TO BE IMPACTED THE MOST. HAVE OPTED
TO KEEP THE COASTAL TERMINALS RAIN FREE BUT WITH VCSH AT LAL LATE
MORNING INTO THE AFTERNOON.
&&
.PRELIMINARY POINT TEMPS/POPS...
TPA 63 82 67 76 / 10 20 40 80
FMY 66 84 67 82 / 10 20 10 60
GIF 63 81 66 80 / 10 30 20 70
SRQ 66 83 66 77 / 10 20 30 80
BKV 62 80 68 76 / 10 30 40 80
SPG 65 79 67 77 / 10 20 40 80
&&
.TBW WATCHES/WARNINGS/ADVISORIES...
FL...NONE.
GULF WATERS...NONE.
&&
$$
UPDATE...MROCZKA
AVIATION...RUDE
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
419 PM CST THU DEC 26 2013
.DISCUSSION...
418 PM CST
MAIN CONCERN FOR THE NEXT SEVERAL DAYS WILL BE THE TEMPERATURE
FORECAST WHICH WILL BE THE TEMPERATURE FORECAST WHICH WILL FEATURE
UNSEASONABLE WARM CONDITIONS FOLLOWED BY AN ARCTIC BLAST.
FOR THE REMAINDER OF THE AFTERNOON AND INTO THIS EVENING WARM
ADVECTION AT THE SURFACE IS OVERCOMING INCREASING CLOUD COVER WITH
TEMPERATURES APPROACHING 40F OVER THE PONTIAC METRO AREA AND WITH
TEMPERATURES DROPPING OFF TO THE NORTH WHERE GREATER SNOWCOVER IS IN
PLACE. LATEST LOOKS OUT THE WINDOW HERE IN ROMEOVILLE SHOW THAT THE
WARM/MOIST ADVECTION AT THE SURFACE IS ALREADY EFFICIENTLY MELTING
THE SNOWCOVER...WHICH WILL HAVE A SIGNIFICANT IMPACT ON THE
TEMPERATURE FORECAST FOR FRIDAY AND SATURDAY.
THE MODELS HAVE BEEN TRENDING WARMER WITH RECENT RUNS BUT STILL FEEL
THAT THE FORECAST SFC MAX TEMPS ARE STILL SIGNIFICANTLY UNDERDONE
DUE TO INADEQUATELY HANDLING THE SNOW MELT. SO...FOR FRIDAY AND
SATURDAY...HAVE SIGNIFICANTLY RAISED MAX TEMPS OVER GUIDANCE. FOR
THE NEXT FEW DAYS...HAVE BEEN LARGELY FOLLOWING THE ECMWF TRENDS
THOUGH THERE ARE NO SIGNIFICANT DIFFERENCES AMONG THE MODELS WITH
TEMPERATURES ALOFT. ON SATURDAY...AT THE 925MB LEVEL...A WEDGE OF
VERY WARM AIR WITH TEMPS OF +2 TO +4C OVERSPREADS THE AREA WHILE BY
SATURDAY THE 925MB TEMPS ARE ADVERTISED IN THE +6 TO +8C.
ALSO...THE DEWPOINT TREND WILL BE UPWARDS AS WELL WITH MIDDLE TO
UPPER 20S FRIDAY AND LOWER TO MIDDLE 30S BY SATURDAY. SO...FEEL
THAT THE ONGOING AND CONTINUED WARM...MOIST ADVECTION WILL MELT OFF
MUCH OR ALL OF THE SNOW COVER...WHICH WILL IN TURN...HELP ENHANCE
THE TEMPERATURE TREND. LATEST THINKING IS THAT HIGHS ON FRIDAY WILL
RANGE FROM THE LOWER 30S OVER THE ROCKFORD AREA...WHERE THE
SNOWCOVER SHOULD LINGER LONGEST...WHILE THE PONTIAC AREA SHOULD
REACH THE LOWERS 40S. THE CHICAGO METRO AND NWRN INDIANA SHOULD BE
IN BETWEEN THIS RANGE WITH HIGHS IN THE MIDDLE TO UPPER 30S...THOUGH
GETTING CLOSE TO 40F IS NOT OUT OF THE REALM OF POSSIBILITY. THE
GREATEST WARMING IS STILL EXPECTED FOR SATURDAY. HAVE BUMPED TEMPS
WITH HIGHS IN THE LOW 50S OVER THE FAR SERN PORTIONS OF THE
CWA...GENERALLY SOUTH OF A LINE FROM RENSSELAER TO
FAIRBURY...DROPPING OFF INTO THE MIDDLE TO UPPER 40S FROM CHICAGO TO
PERU. STILL ANTICIPATE THAT THE ROCKFORD AREA SHOULD LINGER IN THE
UPPER 30S AS THE AXIS OF THE HIGHEST 925MB TEMPS WILL EXTEND FROM
THAT CHICAGO TO PERU LINE. HOWEVER...GIVEN THE UNUSUALLY STRONG
WARM/MOIST ADVECTION AND AMPLE SUNSHINE UNDER MOSTLY SUNNY
SKIES...THERE IS STILL A CHANCE THAT THE FORECAST WARMING TREND
COULD BE A LITTLE CONSERVATIVE AND THAT TEMPS COULD STILL END UP
BEING A LITTLE HIGHER.
AND THEN COMES THE SLAP IN THE FACE. A STRONG COLD FRONT WILL PUSH
THROUGH THE AREA THROUGH THE DAY ON SUNDAY...USHERING IN LARGE AREA
OF ARCTIC HIGH PRESSURE. THE TEMPERATURE TREND FOR SUNDAY WILL BE A
LITTLE TRICKY AS HIGHS WILL LIKELY COME EARLY IN THE MORNING AND
TEMPERATURES WILL DROP OFF THROUGH THE DAY. GIVEN THAT THERE COULD
STILL BE SOME LINGERING LOW LEVEL MOISTURE IN PLACE AHEAD OF THE
FRONT...THERE WILL BE A CHANCE FOR SOME LIGHT SNOW OR SNOWSHOWERS
ALONG AND JUST BEHIND THE FRONT...BUT THE COLD...DRY AIR WILL
QUICKLY OVERSPREAD THE AREA AND ANY PCPN POTENTIAL SHOULD SHUT OFF
RELATIVELY QUICKLY. BY MONDAY MORNING TEMPERATURES OVER MUCH OF THE
CWA WILL DROP BELOW 0F...WITH ONLY LOCATIONS SOUTH AND EAST OF A
PONTIAC TO CHICAGO LINE REMAINING A LITTLE ABOVE 0F. EVEN WITH AMPLE
SUNSHINE...TEMPERATURES ON MONDAY SHOULD REMAIN IN THE SINGLE DIGITS
NORTH OF A LINE FROM CHICAGO TO PONTIAC...WHILE THE REMAINDER OF THE
CWA WILL ONLY PERHAPS REACH THE LOWER TEENS.
FOR THE REMAINDER OF THE FORECAST PERIOD...FROM TUESDAY THROUGH
THURSDAY WILL REMAIN SIGNIFICANTLY BELOW NORMAL WITH LITTLE TO NO
CHANCES FOR PRECIPITATION. AGAIN...HAVE UNDERCUT GUIDANCE WITH
RESPECT TO TEMPERATURES IN THE EXTENDED FORECAST AND TRENDED CLOSER
TO THE WPC MEDIUM RANGE TEMPERATURE GUIDANCE. TEMPERATURES SHOULD
HOLD STEADY THROUGH WEDNESDAY WITH SINGLE DIGITS TO LOWER TEENS
ABOVE 0F FOR HIGHS AND LOWS APPROACHING -10F OVER THE NWRN PORTIONS
OF THE CWA...AND LOWER SINGLE DIGITS ABOVE 0F OVER THE FAR SERN
PORTIONS OF THE CWA. BY FRIDAY THERE MAY BE SOME MODERATION...BUT
TEMPS ARE STILL EXPECTED TO REMAIN A LITTLE BELOW NORMAL.
KREIN
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 22Z...
* DIMINISHING POTENTIAL FOR LIGHT SNOW/FLURRIES INTO EARLY
EVENING.
* CIG TRENDS...AND POTENTIAL FOR MVFR TO RETURN THIS EVENING AND
OVERNIGHT.
RC
//DISCUSSION...UPDATED 22Z...
IT APPEARS THAT THERE IS A MUCH MORE STOUT DRY LAYER THAN
EXPECTED AT THE LOWER LEVELS OF THE ATMOSPHERE. DESPITE AN UPPER
LEVEL DISTURBANCE APPROACHING...THIS IS PREVENTING AND SHOULD
CONTINUE TO PREVENT MOST IF NOT ALL OF THE -SN FROM REACHING THE
SURFACE. PULLED MENTION FROM TAF...BUT EVEN IF FLURRIES
OCCUR...THEY SHOULDNT HAVE ANY OPERATIONAL IMPACT. FOR CIG
TRENDS...NO SIGNS OF LOWERING UPSTREAM OVER IA AND SW WI...SO ITS
ALSO POSSIBLE THAT THE LOW-MID MVFR CIGS WILL AT LEAST BE SLOW TO
MATERIALIZE IF THEY OCCUR AT ALL.
...FROM 18Z...
BAND OF SNOW IS EXITING EAST OF THIS CHICAGO TERMINALS THIS
AFTERNOON BUT A PAIR OF ADDITIONAL UPPER LEVEL DISTURBANCES TO THE
NORTHWEST WILL BRING ADDITIONAL CHANCES FOR SNOW THROUGH PORTIONS
OF THE AFTERNOON AND EVENING. THE FIRST WAVE IS CURRENTLY
DROPPING SOUTHEAST ACROSS IOWA WITH RADAR RETURNS ACROSS MUCH OF
THE EASTERN HALF OF IOWA AND NORTHWEST ILLINOIS. PER SURFACE OBS
HOWEVER...MOST OF THIS IS NOT REACHING THE GROUND...AND APPEARS
THE MAIN FORCING WILL DROP SOUTH OF THE TERMINALS EARLY THIS
AFTERNOON. THE NEXT WAVE IS OVER THE EASTERN DAKOTAS EARLY THIS
AFTERNOON AND WILL TAKE AIM AT THE IL/WI STATE LINE LATE THIS
AFTERNOON AND THIS EVENING. MOST MODELS INDICATE THAT THE
ACCUMULATING SNOWFALL WILL FALL NORTH OF THE TERMINALS...HOWEVER
SOME LIFT IS NOTED AS FAR SOUTH AS THE TERMINALS. ITS NOT CO-
LOCATED WELL WITH THE MOISTURE OR THE SNOW GROWTH ZONE...SO DO NOT
ANTICIPATE EFFICIENT SNOW PRODUCTION WITH THIS WAVE.
INSTEAD...EXPECT A PERIOD OF FLURRIES WITH GENERALLY VFR
CONDITIONS...THOUGH CANNOT RULE OUT PERHAPS A PERIODIC BRIEF DROPS
TO MVFR VSBY. WILL MONITOR UPSTREAM TRENDS THIS AFTERNOON TO
DETERMINE IF THE THREAT IS ENOUGH TO INCLUDE IN TAF.
THERE IS A WEAK SURFACE REFLECTION OF THE SECOND WAVE THIS EVENING.
SSW TO SW WINDS AHEAD OF THE SURFACE TROUGH WILL VEER TO THE WSW OR
WEST FOR A PERIOD THIS EVENING. BEHIND THIS SLIGHT WIND
SHIFT...FORECAST SOUNDINGS SHOW SATURATION OF THE LOWER LEVELS
INDICATING THE DEVELOPMENT OF MVFR OR IN SOME CASES IFR CIGS. MET
GUIDANCE INDICATES A SIMILAR DROP IN CIGS OVERNIGHT...WHILE MAV/LAV
GUIDANCE DOES NOT. WILL INTRODUCE MVFR CIGS INTO THE FORECAST...BUT
AM CONCERNED THAT LOWER CIGS ARE POSSIBLE. RAP LOW LEVEL MOISTURE
FIELDS INDICATE THESE CIGS WILL DEVELOP NEAR THE MISSISSIPPI RIVER
MID TO LATE THIS AFTERNOON...SO WILL GAIN MORE CONFIDENCE IN CIG
TRENDS BY THEN.
BMD
//ORD AND MDW CONFIDENCE...UPDATED 22Z...
* HIGH CONFIDENCE THAT IF ANY FLURRIES OCCUR THROUGH EARLY
EVENING...THERE WILL BE NO OPERATIONAL IMPACT.
* LOW CONFIDENCE IN CIG TRENDS THIS EVENING/OVERNIGHT REGARDING
DEVELOPMENT OF MVFR CIGS.
RC
//OUTLOOK FOR ORD/MDW FOR 00Z SATURDAY-12Z THURSDAY...UPDATED 12Z...
FRIDAY NIGHT...VFR WIND.
SATURDAY...VFR WIND.
SUNDAY THROUGH TUESDAY NIGHT...PERIODS OF -SN WITH OCNL MVFR
CIGS/VSBY. A PERIOD OF IFR CIGS/VIS POSSIBLE.
WEDNESDAY...VFR WX NIL.
ED F
&&
.MARINE...
232 PM...A WEAK RIDGE CURRENTLY OVER THE WESTERN LAKES REGION
WILL DRIFT SOUTHEAST TONIGHT AND BE ABSORBED BY A MUCH LARGER AND
STRONGER HIGH OVER THE OHIO VALLEY. A FAST MOVING LOW WILL MOVE
ACROSS CENTRAL ONTARIO AND THE NORTHERN LAKES FRIDAY. THE GRADIENT
WILL TIGHTEN BETWEEN THIS APPROACHING LOW AND THE STRONG HIGH TO
THE SOUTH WITH GALES POSSIBLE ESPECIALLY ACROSS THE NORTHERN HALF
OF LAKE MICHIGAN. OVERALL DURATION PERHAPS 6 TO 9 HOURS AND HAVE
HOISTED A GALE WATCH FOR FRIDAY AFTERNOON/FRIDAY EVENING. AS THE
LOW LIFTS NORTHEAST INTO QUEBEC FRIDAY NIGHT...THE GRADIENT WILL
WEAKEN AND WHILE ITS POSSIBLE THERE COULD BE SOME GALE GUSTS ON
THE SOUTH HALF OF THE LAKE...CONFIDENCE DECREASES FURTHER SOUTH
AND HAVE HELD WINDS AT 30 KTS. A TRAILING COLD FRONT FROM THIS LOW
WILL SAG SOUTH ACROSS NORTHERN LAKE MICHIGAN SATURDAY EVENING WITH
NEW LOW PRESSURE FORMING OF THE PLAINS SATURDAY AND THEN MOVING
EAST/NORTHEAST ALONG THIS FRONT SATURDAY NIGHT INTO SUNDAY
MORNING. THIS WILL LIKELY SLOW THE FRONT/S PROGRESS SOUTH DOWN
LAKE MICHIGAN WITH SOUTHWESTERLY FLOW EXPECTED AHEAD OF THE FRONT
SATURDAY NIGHT. THE GRADIENT WILL TIGHTEN SHARPLY BEHIND THE FRONT
AND COMBINED WITH STRONG COLD AIR SPREADING ACROSS THE REGION...
NORTHERLY WINDS SHOULD EASILY INCREASE TO 30 KTS AND ITS POSSIBLE
FOR A PERIOD OF LOW END GALES. NORTHERLY WINDS WILL SLOWLY TURN
NORTHWEST SUNDAY INTO MONDAY AND GRADUALLY DIMINISH. CMS
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...GALE WATCH...LMZ261-LMZ362-LMZ364-LMZ366-LMZ563-LMZ565-LMZ567-
LMZ868...NOON FRIDAY TO MIDNIGHT SATURDAY.
&&
$$
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AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
416 PM CST THU DEC 26 2013
.DISCUSSION...
930 AM CST
HAVE MADE SOME MINOR ADJUSTMENTS TO THE WX/POP/QPS FOR THE REST OF
THIS MORNING AND INTO THIS AFTERNOON. A SERIES OF SHORTWAVES
RIPPLING THROUGH THE FAST NORTHWEST FLOW ALOFT ARE ALREADY
GENERATING SOME LIGHT SNOW ACROSS NRN IL. THE LATEST GUIDANCE AND
UPSTREAM SATELLITE IMAGERY SUGGEST THAT A COUPLE MORE ORGANIZED
SHORTWAVES WILL TRAVERSE THE NRN PORTIONS OF THE CWA THIS
AFTERNOON. SO HAVE BUMPED UP POPS FOR THE REMAINDER OF TODAY.
WHILE THIS LOOKS TO BE MORE OF A HIGHER POP...LOWER QPF
SITUATION...WILL STILL CARRY MEASURABLE PCPN FOR THIS AFTERNOON...
BUT GIVEN THE EXPECTATIONS OF RELATIVELY HIGH SNOW TO LIQUID RATIO
LIKELY...ANY SNOWFALL WOULD MOST LIKELY BE OBSERVED AS A DUSTING
AND DIFFICULT TO ACTUALLY MEASURE.
KREIN
.PREVIOUS DISCUSSION...
335 AM CST
SYNOPSIS...LIGHT SNOW IS POSSIBLE THIS AFTERNOON ALONG THE IL/WI
STATE LINE...THEN THE WARM UP IS ON THROUGH SATURDAY. TEMPS CRASH
BEHIND THE LOW SUNDAY WITH VERY COLD AIR RETURNING TO THE REGION.
SNOW IS POSSIBLE ON SUNDAY BUT THE BETTER CHANCE LOOKS TO BE MONDAY
NIGHT INTO TUESDAY.
TODAY AND TONIGHT...
THE UPPER LEVEL TROUGH AXIS HAS PUSHED EAST OF THE AREA ALONG WITH
THE SNOW WE SAW LAST NIGHT. AT THE SURFACE...WEAK LOW PRESSURE IS
OVER SOUTHWESTERN ONTARIO. HIGH PRESSURE IS CENTERED OVER TEXARKANA
BUT ITS RIDGE EXTENDS NORTH THROUGH THE MISSISSIPPI RIVER VALLEY.
THE RIDGE WILL MOVE OVERHEAD THIS MORNING WHILE THE MAIN HIGH
REMAINS TO OUR SOUTH.
A WEAK SHORTWAVE PASSES THROUGH WI THIS AFTN KICKING OFF SNOW
SHOWERS. THE MAIN VORT WILL BE OVER CENTRAL WI SO THINKING THE
MAJORITY OF PRECIP WILL BE OVER WI...BUT COULD SEE A HALF INCH OR
LESS ALONG THE IL/WI STATE LINE. MODEL SOUNDINGS SUPPORT THIS AS
THEY SHOW OMEGA REMAINING LOWER THAN THE SATURATED DGZ LAYER. THEN
AS OMEGA LIFTS INTO THE SATURATED LAYER...THE OMEGA WEAKENS GREATLY
AND THE SATURATION ALSO WEAKENS.
WINDS TURN SW AND WEAK WAA WILL LEAD TO HIGH TEMPS IN THE MID TO
UPPER 20S. FAR SOUTHERN AREAS IN THE CWA MAY EVEN MAKE OR BREAK
FREEZING AS THEY DO NOT HAVE ANY SNOW ON THE GROUND AND WILL SEE
SOME SUN. WAA CONTINUES THROUGH TONIGHT...BUT THE SNOWPACK WILL
WREAK HAVOC WITH LOW TEMPS. WINDS LIGHTEN DUE TO THE BAGGY PRESSURE
PATTERN AND CLOUDS THIN OVERNIGHT. THE GOING LOW TEMPS LOOKED VERY
REASONABLE...THEREFORE DID NOT MAKE ANY MAJOR CHANGES. HAVE TEENS
OVER NORTH CENTRAL IL AND THEN LOW 20S IN THE SOUTHEAST CORNER OF
THE CWA.
FRIDAY AND SATURDAY...
UPPER LEVEL FLOW TURNS ZONAL THROUGH SATURDAY AND WAA REALLY KICKS
INTO HIGH GEAR FRIDAY AND SATURDAY. A LOW PASSES WELL TO OUR
NORTH...BUT WITH THE HIGH OVER THE GULF COAST...THE PRESSURE
GRADIENT TIGHTENS AND WINDS PICK UP. SW WINDS AROUND 10 KT WITH
GUSTS 15 TO 20 KT WILL HELP USHER IN THE WARMER AIR. GUIDANCE HAS
925MB TEMPS RISING TO +4C BY FRIDAY EVENING AND THEN TO +6 TO +8 BY
SATURDAY EVENING. AS SUCH RAISED TEMPS FRIDAY...FRIDAY NIGHT...AND
SATURDAY. CONFIDENCE IS MEDIUM-HIGH IN THE GOING FORECAST TEMPS FOR
THAT PERIOD.
FOR NOW CONTINUED THE TREND THAT THE END OF THIS WEEK LOOKS ABOVE
NORMAL IN THE TEMP DEPARTMENT. HOW WARM...NOT SURE. FOR AREAS WITH
LITTLE SNOW...ROUGHLY AREAS ALONG AND SOUTH OF I-88...THE WARM UP
COULD BE WARMER THAN CURRENTLY FORECAST. FOR NOW THINKING ABOVE
FREEZING ON FRIDAY AND 40S ON SATURDAY SEEM REASONABLE. FOR AREAS
NORTH OF I-88 THAT HAVE A DECENT SNOW PACK...THINGS COULD BE MORE
DICEY. RFD FOR INSTANCE HAS 7 INCHES OF SNOW ON THE GROUND...AND
THE WAA ADVECTION AND NEAR FREEZING TEMPS ON FRIDAY MAY NOT MAKE A
SIGNIFICANT DENT IN THE SNOW. AS SUCH WENT NEAR GUIDANCE FOR
THESE NORTHERN AREAS WITH TEMPS JUST ABOVE FREEZING FRIDAY...AND
AROUND 40 SATURDAY. COULD CERTAINLY SEE A TIGHT TEMP GRADIENT
WITHIN THE CWA AS THE SNOW FREE AREAS WARM QUICKLY...WHILE THE AREAS
WITH SNOW PACK STRUGGLE TO CLIMB.
EXTENDED...SUNDAY THROUGH TUESDAY...
THE SURFACE LOW SINKS SOUTH...MOVING OVER THE CWA SATURDAY NIGHT
INTO SUNDAY. AN UPPER LEVEL STREAMER ASSOCIATED WITH THE LOW
WEAKENS AS THE STRONGER UPPER LEVEL TROUGH CATCHES UP WITH THE LOW.
PRECIP IS EXPECTED ALONG AND BEHIND THE COLD FRONT. GUIDANCE
DIFFERS A BIT ON THE TIMING OF THE LOW AND AS TO HOW MUCH FORCING
WILL ACCOMPANY IT. THE GFS IS MORE VIGOROUS THAN THE ECMWF WITH
PRECIP...WHILE THE ECMWF IS A BIT FASTER. AS SUCH LEFT POPS IN THE
CHANCE RANGE UNTIL THE FORCING AND TIMING ASPECTS BECOME A BIT
CLEARER. OVERALL NOT EXPECTING A LOT OF PRECIP/SNOW.
THE BIGGER STORY WILL BE TEMPS. TEMPS WILL FALL SUNDAY AS COLD AIR
CONTINUES TO FUNNEL IN BEHIND THE TROUGH AXIS. 925MB TEMPS FALL TO
-4 TO -14C ALOFT BY SUNDAY EVENING WITH COLDER AIR EXPECTED
OVERNIGHT. HIGH PRESSURE ALSO APPROACHES FROM THE WEST SO CLEARING
SKIES AND NORTHWEST WINDS AROUND 10 KT WILL LEAD TO A VERY COLD
NIGHT. LOW TEMPS WILL RANGE FROM BELOW ZERO OVER NORTH CENTRAL IL TO
SINGLE DIGITS OVER NW INDIANA. MIN WIND CHILLS BELOW -20 ARE STILL
EXPECTED ACROSS NORTH CENTRAL IL SUNDAY NIGHT AND MONDAY NIGHT.
COLD CONTINUES THROUGH NEW YEARS EVE WITH A SLIGHT RELIEF EXPECTED
ON JAN 1ST. GUIDANCE CONTINUES TO HINT AT A PRECIP SYSTEM
TUESDAY...BUT GUIDANCE IS LESS CLEAR ON FORCING AND TIMING TODAY
COMPARED TO YESTERDAY. THEREFORE LEFT SLIGHT CHANCE TO CHANCE POPS
IN THROUGH MID WEEK.
JEE
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 22Z...
* DIMINISHING POTENTIAL FOR LIGHT SNOW/FLURRIES INTO EARLY
EVENING.
* CIG TRENDS...AND POTENTIAL FOR MVFR TO RETURN THIS EVENING AND
OVERNIGHT.
RC
//DISCUSSION...UPDATED 22Z...
IT APPEARS THAT THERE IS A MUCH MORE STOUT DRY LAYER THAN
EXPECTED AT THE LOWER LEVELS OF THE ATMOSPHERE. DESPITE AN UPPER
LEVEL DISTURBANCE APPROACHING...THIS IS PREVENTING AND SHOULD
CONTINUE TO PREVENT MOST IF NOT ALL OF THE -SN FROM REACHING THE
SURFACE. PULLED MENTION FROM TAF...BUT EVEN IF FLURRIES
OCCUR...THEY SHOULDNT HAVE ANY OPERATIONAL IMPACT. FOR CIG
TRENDS...NO SIGNS OF LOWERING UPSTREAM OVER IA AND SW WI...SO ITS
ALSO POSSIBLE THAT THE LOW-MID MVFR CIGS WILL AT LEAST BE SLOW TO
MATERIALIZE IF THEY OCCUR AT ALL.
...FROM 18Z...
BAND OF SNOW IS EXITING EAST OF THIS CHICAGO TERMINALS THIS
AFTERNOON BUT A PAIR OF ADDITIONAL UPPER LEVEL DISTURBANCES TO THE
NORTHWEST WILL BRING ADDITIONAL CHANCES FOR SNOW THROUGH PORTIONS
OF THE AFTERNOON AND EVENING. THE FIRST WAVE IS CURRENTLY
DROPPING SOUTHEAST ACROSS IOWA WITH RADAR RETURNS ACROSS MUCH OF
THE EASTERN HALF OF IOWA AND NORTHWEST ILLINOIS. PER SURFACE OBS
HOWEVER...MOST OF THIS IS NOT REACHING THE GROUND...AND APPEARS
THE MAIN FORCING WILL DROP SOUTH OF THE TERMINALS EARLY THIS
AFTERNOON. THE NEXT WAVE IS OVER THE EASTERN DAKOTAS EARLY THIS
AFTERNOON AND WILL TAKE AIM AT THE IL/WI STATE LINE LATE THIS
AFTERNOON AND THIS EVENING. MOST MODELS INDICATE THAT THE
ACCUMULATING SNOWFALL WILL FALL NORTH OF THE TERMINALS...HOWEVER
SOME LIFT IS NOTED AS FAR SOUTH AS THE TERMINALS. ITS NOT CO-
LOCATED WELL WITH THE MOISTURE OR THE SNOW GROWTH ZONE...SO DO NOT
ANTICIPATE EFFICIENT SNOW PRODUCTION WITH THIS WAVE.
INSTEAD...EXPECT A PERIOD OF FLURRIES WITH GENERALLY VFR
CONDITIONS...THOUGH CANNOT RULE OUT PERHAPS A PERIODIC BRIEF DROPS
TO MVFR VSBY. WILL MONITOR UPSTREAM TRENDS THIS AFTERNOON TO
DETERMINE IF THE THREAT IS ENOUGH TO INCLUDE IN TAF.
THERE IS A WEAK SURFACE REFLECTION OF THE SECOND WAVE THIS EVENING.
SSW TO SW WINDS AHEAD OF THE SURFACE TROUGH WILL VEER TO THE WSW OR
WEST FOR A PERIOD THIS EVENING. BEHIND THIS SLIGHT WIND
SHIFT...FORECAST SOUNDINGS SHOW SATURATION OF THE LOWER LEVELS
INDICATING THE DEVELOPMENT OF MVFR OR IN SOME CASES IFR CIGS. MET
GUIDANCE INDICATES A SIMILAR DROP IN CIGS OVERNIGHT...WHILE MAV/LAV
GUIDANCE DOES NOT. WILL INTRODUCE MVFR CIGS INTO THE FORECAST...BUT
AM CONCERNED THAT LOWER CIGS ARE POSSIBLE. RAP LOW LEVEL MOISTURE
FIELDS INDICATE THESE CIGS WILL DEVELOP NEAR THE MISSISSIPPI RIVER
MID TO LATE THIS AFTERNOON...SO WILL GAIN MORE CONFIDENCE IN CIG
TRENDS BY THEN.
BMD
//ORD AND MDW CONFIDENCE...UPDATED 22Z...
* HIGH CONFIDENCE THAT IF ANY FLURRIES OCCUR THROUGH EARLY
EVENING...THERE WILL BE NO OPERATIONAL IMPACT.
* LOW CONFIDENCE IN CIG TRENDS THIS EVENING/OVERNIGHT REGARDING
DEVELOPMENT OF MVFR CIGS.
RC
//OUTLOOK FOR ORD/MDW FOR 00Z SATURDAY-12Z THURSDAY...UPDATED 12Z...
FRIDAY NIGHT...VFR WIND.
SATURDAY...VFR WIND.
SUNDAY THROUGH TUESDAY NIGHT...PERIODS OF -SN WITH OCNL MVFR
CIGS/VSBY. A PERIOD OF IFR CIGS/VIS POSSIBLE.
WEDNESDAY...VFR WX NIL.
ED F
&&
.MARINE...
232 PM...A WEAK RIDGE CURRENTLY OVER THE WESTERN LAKES REGION
WILL DRIFT SOUTHEAST TONIGHT AND BE ABSORBED BY A MUCH LARGER AND
STRONGER HIGH OVER THE OHIO VALLEY. A FAST MOVING LOW WILL MOVE
ACROSS CENTRAL ONTARIO AND THE NORTHERN LAKES FRIDAY. THE GRADIENT
WILL TIGHTEN BETWEEN THIS APPROACHING LOW AND THE STRONG HIGH TO
THE SOUTH WITH GALES POSSIBLE ESPECIALLY ACROSS THE NORTHERN HALF
OF LAKE MICHIGAN. OVERALL DURATION PERHAPS 6 TO 9 HOURS AND HAVE
HOISTED A GALE WATCH FOR FRIDAY AFTERNOON/FRIDAY EVENING. AS THE
LOW LIFTS NORTHEAST INTO QUEBEC FRIDAY NIGHT...THE GRADIENT WILL
WEAKEN AND WHILE ITS POSSIBLE THERE COULD BE SOME GALE GUSTS ON
THE SOUTH HALF OF THE LAKE...CONFIDENCE DECREASES FURTHER SOUTH
AND HAVE HELD WINDS AT 30 KTS. A TRAILING COLD FRONT FROM THIS LOW
WILL SAG SOUTH ACROSS NORTHERN LAKE MICHIGAN SATURDAY EVENING WITH
NEW LOW PRESSURE FORMING OF THE PLAINS SATURDAY AND THEN MOVING
EAST/NORTHEAST ALONG THIS FRONT SATURDAY NIGHT INTO SUNDAY
MORNING. THIS WILL LIKELY SLOW THE FRONT/S PROGRESS SOUTH DOWN
LAKE MICHIGAN WITH SOUTHWESTERLY FLOW EXPECTED AHEAD OF THE FRONT
SATURDAY NIGHT. THE GRADIENT WILL TIGHTEN SHARPLY BEHIND THE FRONT
AND COMBINED WITH STRONG COLD AIR SPREADING ACROSS THE REGION...
NORTHERLY WINDS SHOULD EASILY INCREASE TO 30 KTS AND ITS POSSIBLE
FOR A PERIOD OF LOW END GALES. NORTHERLY WINDS WILL SLOWLY TURN
NORTHWEST SUNDAY INTO MONDAY AND GRADUALLY DIMINISH. CMS
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...GALE WATCH...LMZ261-LMZ362-LMZ364-LMZ366-LMZ563-LMZ565-LMZ567-
LMZ868...NOON FRIDAY TO MIDNIGHT SATURDAY.
&&
$$
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
232 PM CST THU DEC 26 2013
.DISCUSSION...
930 AM CST
HAVE MADE SOME MINOR ADJUSTMENTS TO THE WX/POP/QPS FOR THE REST OF
THIS MORNING AND INTO THIS AFTERNOON. A SERIES OF SHORTWAVES
RIPPLING THROUGH THE FAST NORTHWEST FLOW ALOFT ARE ALREADY
GENERATING SOME LIGHT SNOW ACROSS NRN IL. THE LATEST GUIDANCE AND
UPSTREAM SATELLITE IMAGERY SUGGEST THAT A COUPLE MORE ORGANIZED
SHORTWAVES WILL TRAVERSE THE NRN PORTIONS OF THE CWA THIS
AFTERNOON. SO HAVE BUMPED UP POPS FOR THE REMAINDER OF TODAY.
WHILE THIS LOOKS TO BE MORE OF A HIGHER POP...LOWER QPF
SITUATION...WILL STILL CARRY MEASURABLE PCPN FOR THIS AFTERNOON...
BUT GIVEN THE EXPECTATIONS OF RELATIVELY HIGH SNOW TO LIQUID RATIO
LIKELY...ANY SNOWFALL WOULD MOST LIKELY BE OBSERVED AS A DUSTING
AND DIFFICULT TO ACTUALLY MEASURE.
KREIN
.PREVIOUS DISCUSSION...
335 AM CST
SYNOPSIS...LIGHT SNOW IS POSSIBLE THIS AFTERNOON ALONG THE IL/WI
STATE LINE...THEN THE WARM UP IS ON THROUGH SATURDAY. TEMPS CRASH
BEHIND THE LOW SUNDAY WITH VERY COLD AIR RETURNING TO THE REGION.
SNOW IS POSSIBLE ON SUNDAY BUT THE BETTER CHANCE LOOKS TO BE MONDAY
NIGHT INTO TUESDAY.
TODAY AND TONIGHT...
THE UPPER LEVEL TROUGH AXIS HAS PUSHED EAST OF THE AREA ALONG WITH
THE SNOW WE SAW LAST NIGHT. AT THE SURFACE...WEAK LOW PRESSURE IS
OVER SOUTHWESTERN ONTARIO. HIGH PRESSURE IS CENTERED OVER TEXARKANA
BUT ITS RIDGE EXTENDS NORTH THROUGH THE MISSISSIPPI RIVER VALLEY.
THE RIDGE WILL MOVE OVERHEAD THIS MORNING WHILE THE MAIN HIGH
REMAINS TO OUR SOUTH.
A WEAK SHORTWAVE PASSES THROUGH WI THIS AFTN KICKING OFF SNOW
SHOWERS. THE MAIN VORT WILL BE OVER CENTRAL WI SO THINKING THE
MAJORITY OF PRECIP WILL BE OVER WI...BUT COULD SEE A HALF INCH OR
LESS ALONG THE IL/WI STATE LINE. MODEL SOUNDINGS SUPPORT THIS AS
THEY SHOW OMEGA REMAINING LOWER THAN THE SATURATED DGZ LAYER. THEN
AS OMEGA LIFTS INTO THE SATURATED LAYER...THE OMEGA WEAKENS GREATLY
AND THE SATURATION ALSO WEAKENS.
WINDS TURN SW AND WEAK WAA WILL LEAD TO HIGH TEMPS IN THE MID TO
UPPER 20S. FAR SOUTHERN AREAS IN THE CWA MAY EVEN MAKE OR BREAK
FREEZING AS THEY DO NOT HAVE ANY SNOW ON THE GROUND AND WILL SEE
SOME SUN. WAA CONTINUES THROUGH TONIGHT...BUT THE SNOWPACK WILL
WREAK HAVOC WITH LOW TEMPS. WINDS LIGHTEN DUE TO THE BAGGY PRESSURE
PATTERN AND CLOUDS THIN OVERNIGHT. THE GOING LOW TEMPS LOOKED VERY
REASONABLE...THEREFORE DID NOT MAKE ANY MAJOR CHANGES. HAVE TEENS
OVER NORTH CENTRAL IL AND THEN LOW 20S IN THE SOUTHEAST CORNER OF
THE CWA.
FRIDAY AND SATURDAY...
UPPER LEVEL FLOW TURNS ZONAL THROUGH SATURDAY AND WAA REALLY KICKS
INTO HIGH GEAR FRIDAY AND SATURDAY. A LOW PASSES WELL TO OUR
NORTH...BUT WITH THE HIGH OVER THE GULF COAST...THE PRESSURE
GRADIENT TIGHTENS AND WINDS PICK UP. SW WINDS AROUND 10 KT WITH
GUSTS 15 TO 20 KT WILL HELP USHER IN THE WARMER AIR. GUIDANCE HAS
925MB TEMPS RISING TO +4C BY FRIDAY EVENING AND THEN TO +6 TO +8 BY
SATURDAY EVENING. AS SUCH RAISED TEMPS FRIDAY...FRIDAY NIGHT...AND
SATURDAY. CONFIDENCE IS MEDIUM-HIGH IN THE GOING FORECAST TEMPS FOR
THAT PERIOD.
FOR NOW CONTINUED THE TREND THAT THE END OF THIS WEEK LOOKS ABOVE
NORMAL IN THE TEMP DEPARTMENT. HOW WARM...NOT SURE. FOR AREAS WITH
LITTLE SNOW...ROUGHLY AREAS ALONG AND SOUTH OF I-88...THE WARM UP
COULD BE WARMER THAN CURRENTLY FORECAST. FOR NOW THINKING ABOVE
FREEZING ON FRIDAY AND 40S ON SATURDAY SEEM REASONABLE. FOR AREAS
NORTH OF I-88 THAT HAVE A DECENT SNOW PACK...THINGS COULD BE MORE
DICEY. RFD FOR INSTANCE HAS 7 INCHES OF SNOW ON THE GROUND...AND
THE WAA ADVECTION AND NEAR FREEZING TEMPS ON FRIDAY MAY NOT MAKE A
SIGNIFICANT DENT IN THE SNOW. AS SUCH WENT NEAR GUIDANCE FOR
THESE NORTHERN AREAS WITH TEMPS JUST ABOVE FREEZING FRIDAY...AND
AROUND 40 SATURDAY. COULD CERTAINLY SEE A TIGHT TEMP GRADIENT
WITHIN THE CWA AS THE SNOW FREE AREAS WARM QUICKLY...WHILE THE AREAS
WITH SNOW PACK STRUGGLE TO CLIMB.
EXTENDED...SUNDAY THROUGH TUESDAY...
THE SURFACE LOW SINKS SOUTH...MOVING OVER THE CWA SATURDAY NIGHT
INTO SUNDAY. AN UPPER LEVEL STREAMER ASSOCIATED WITH THE LOW
WEAKENS AS THE STRONGER UPPER LEVEL TROUGH CATCHES UP WITH THE LOW.
PRECIP IS EXPECTED ALONG AND BEHIND THE COLD FRONT. GUIDANCE
DIFFERS A BIT ON THE TIMING OF THE LOW AND AS TO HOW MUCH FORCING
WILL ACCOMPANY IT. THE GFS IS MORE VIGOROUS THAN THE ECMWF WITH
PRECIP...WHILE THE ECMWF IS A BIT FASTER. AS SUCH LEFT POPS IN THE
CHANCE RANGE UNTIL THE FORCING AND TIMING ASPECTS BECOME A BIT
CLEARER. OVERALL NOT EXPECTING A LOT OF PRECIP/SNOW.
THE BIGGER STORY WILL BE TEMPS. TEMPS WILL FALL SUNDAY AS COLD AIR
CONTINUES TO FUNNEL IN BEHIND THE TROUGH AXIS. 925MB TEMPS FALL TO
-4 TO -14C ALOFT BY SUNDAY EVENING WITH COLDER AIR EXPECTED
OVERNIGHT. HIGH PRESSURE ALSO APPROACHES FROM THE WEST SO CLEARING
SKIES AND NORTHWEST WINDS AROUND 10 KT WILL LEAD TO A VERY COLD
NIGHT. LOW TEMPS WILL RANGE FROM BELOW ZERO OVER NORTH CENTRAL IL TO
SINGLE DIGITS OVER NW INDIANA. MIN WIND CHILLS BELOW -20 ARE STILL
EXPECTED ACROSS NORTH CENTRAL IL SUNDAY NIGHT AND MONDAY NIGHT.
COLD CONTINUES THROUGH NEW YEARS EVE WITH A SLIGHT RELIEF EXPECTED
ON JAN 1ST. GUIDANCE CONTINUES TO HINT AT A PRECIP SYSTEM
TUESDAY...BUT GUIDANCE IS LESS CLEAR ON FORCING AND TIMING TODAY
COMPARED TO YESTERDAY. THEREFORE LEFT SLIGHT CHANCE TO CHANCE POPS
IN THROUGH MID WEEK.
JEE
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 20Z...
* LIGHT SNOW/FLURRIES LATE THIS AFTERNOON AND EARLY EVENING.
* CIG TRENDS...AND POTENTIAL FOR MVFR TO RETURN THIS EVENING AND
OVERNIGHT.
BMD
//DISCUSSION...UPDATED 18Z...
BAND OF SNOW IS EXITING EAST OF THIS CHICAGO TERMINALS THIS
AFTERNOON BUT A PAIR OF ADDITIONAL UPPER LEVEL DISTURBANCES TO THE
NORTHWEST WILL BRING ADDITIONAL CHANCES FOR SNOW THROUGH PORTIONS
OF THE AFTERNOON AND EVENING. THE FIRST WAVE IS CURRENTLY
DROPPING SOUTHEAST ACROSS IOWA WITH RADAR RETURNS ACROSS MUCH OF
THE EASTERN HALF OF IOWA AND NORTHWEST ILLINOIS. PER SURFACE OBS
HOWEVER...MOST OF THIS IS NOT REACHING THE GROUND...AND APPEARS
THE MAIN FORCING WILL DROP SOUTH OF THE TERMINALS EARLY THIS
AFTERNOON. THE NEXT WAVE IS OVER THE EASTERN DAKOTAS EARLY THIS
AFTERNOON AND WILL TAKE AIM AT THE IL/WI STATE LINE LATE THIS
AFTERNOON AND THIS EVENING. MOST MODELS INDICATE THAT THE
ACCUMULATING SNOWFALL WILL FALL NORTH OF THE TERMINALS...HOWEVER
SOME LIFT IS NOTED AS FAR SOUTH AS THE TERMINALS. ITS NOT CO-
LOCATED WELL WITH THE MOISTURE OR THE SNOW GROWTH ZONE...SO DO NOT
ANTICIPATE EFFICIENT SNOW PRODUCTION WITH THIS WAVE.
INSTEAD...EXPECT A PERIOD OF FLURRIES WITH GENERALLY VFR
CONDITIONS...THOUGH CANNOT RULE OUT PERHAPS A PERIODIC BRIEF DROPS
TO MVFR VSBY. WILL MONITOR UPSTREAM TRENDS THIS AFTERNOON TO
DETERMINE IF THE THREAT IS ENOUGH TO INCLUDE IN TAF.
THERE IS A WEAK SURFACE REFLECTION OF THE SECOND WAVE THIS EVENING.
SSW TO SW WINDS AHEAD OF THE SURFACE TROUGH WILL VEER TO THE WSW OR
WEST FOR A PERIOD THIS EVENING. BEHIND THIS SLIGHT WIND
SHIFT...FORECAST SOUNDINGS SHOW SATURATION OF THE LOWER LEVELS
INDICATING THE DEVELOPMENT OF MVFR OR IN SOME CASES IFR CIGS. MET
GUIDANCE INDICATES A SIMILAR DROP IN CIGS OVERNIGHT...WHILE MAV/LAV
GUIDANCE DOES NOT. WILL INTRODUCE MVFR CIGS INTO THE FORECAST...BUT
AM CONCERNED THAT LOWER CIGS ARE POSSIBLE. RAP LOW LEVEL MOISTURE
FIELDS INDICATE THESE CIGS WILL DEVELOP NEAR THE MISSISSIPPI RIVER
MID TO LATE THIS AFTERNOON...SO WILL GAIN MORE CONFIDENCE IN CIG
TRENDS BY THEN.
BMD
//ORD AND MDW CONFIDENCE...UPDATED 20Z...
* MEDIUM CONFIDENCE IN PRECIP/VSBY TRENDS.
* MEDIUM CONFIDENCE IN CIG TRENDS THROUGH THE AFTERNOON...THEN LOW
CONFIDENCE THIS EVENING/OVERNIGHT.
BMD
//OUTLOOK FOR ORD/MDW FOR 00Z SATURDAY-12Z THURSDAY...UPDATED 12Z...
FRIDAY NIGHT...VFR WIND.
SATURDAY...VFR WIND.
SUNDAY THROUGH TUESDAY NIGHT...PERIODS OF -SN WITH OCNL MVFR
CIGS/VSBY. A PERIOD OF IFR CIGS/VIS POSSIBLE.
WEDNESDAY...VFR WX NIL.
ED F
&&
.MARINE...
232 PM...A WEAK RIDGE CURRENTLY OVER THE WESTERN LAKES REGION
WILL DRIFT SOUTHEAST TONIGHT AND BE ABSORBED BY A MUCH LARGER AND
STRONGER HIGH OVER THE OHIO VALLEY. A FAST MOVING LOW WILL MOVE
ACROSS CENTRAL ONTARIO AND THE NORTHERN LAKES FRIDAY. THE GRADIENT
WILL TIGHTEN BETWEEN THIS APPROACHING LOW AND THE STRONG HIGH TO
THE SOUTH WITH GALES POSSIBLE ESPECIALLY ACROSS THE NORTHERN HALF
OF LAKE MICHIGAN. OVERALL DURATION PERHAPS 6 TO 9 HOURS AND HAVE
HOISTED A GALE WATCH FOR FRIDAY AFTERNOON/FRIDAY EVENING. AS THE
LOW LIFTS NORTHEAST INTO QUEBEC FRIDAY NIGHT...THE GRADIENT WILL
WEAKEN AND WHILE ITS POSSIBLE THERE COULD BE SOME GALE GUSTS ON
THE SOUTH HALF OF THE LAKE...CONFIDENCE DECREASES FURTHER SOUTH
AND HAVE HELD WINDS AT 30 KTS. A TRAILING COLD FRONT FROM THIS LOW
WILL SAG SOUTH ACROSS NORTHERN LAKE MICHIGAN SATURDAY EVENING WITH
NEW LOW PRESSURE FORMING OF THE PLAINS SATURDAY AND THEN MOVING
EAST/NORTHEAST ALONG THIS FRONT SATURDAY NIGHT INTO SUNDAY
MORNING. THIS WILL LIKELY SLOW THE FRONT/S PROGRESS SOUTH DOWN
LAKE MICHIGAN WITH SOUTHWESTERLY FLOW EXPECTED AHEAD OF THE FRONT
SATURDAY NIGHT. THE GRADIENT WILL TIGHTEN SHARPLY BEHIND THE FRONT
AND COMBINED WITH STRONG COLD AIR SPREADING ACROSS THE REGION...
NORTHERLY WINDS SHOULD EASILY INCREASE TO 30 KTS AND ITS POSSIBLE
FOR A PERIOD OF LOW END GALES. NORTHERLY WINDS WILL SLOWLY TURN
NORTHWEST SUNDAY INTO MONDAY AND GRADUALLY DIMINISH. CMS
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...GALE WATCH...LMZ261-LMZ362-LMZ364-LMZ366-LMZ563-LMZ565-LMZ567-
LMZ868...NOON FRIDAY TO MIDNIGHT SATURDAY.
&&
$$
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
147 PM CST THU DEC 26 2013
.DISCUSSION...
930 AM CST
HAVE MADE SOME MINOR ADJUSTMENTS TO THE WX/POP/QPS FOR THE REST OF
THIS MORNING AND INTO THIS AFTERNOON. A SERIES OF SHORTWAVES
RIPPLING THROUGH THE FAST NORTHWEST FLOW ALOFT ARE ALREADY
GENERATING SOME LIGHT SNOW ACROSS NRN IL. THE LATEST GUIDANCE AND
UPSTREAM SATELLITE IMAGERY SUGGEST THAT A COUPLE MORE ORGANIZED
SHORTWAVES WILL TRAVERSE THE NRN PORTIONS OF THE CWA THIS
AFTERNOON. SO HAVE BUMPED UP POPS FOR THE REMAINDER OF TODAY.
WHILE THIS LOOKS TO BE MORE OF A HIGHER POP...LOWER QPF
SITUATION...WILL STILL CARRY MEASURABLE PCPN FOR THIS AFTERNOON...
BUT GIVEN THE EXPECTATIONS OF RELATIVELY HIGH SNOW TO LIQUID RATIO
LIKELY...ANY SNOWFALL WOULD MOST LIKELY BE OBSERVED AS A DUSTING
AND DIFFICULT TO ACTUALLY MEASURE.
KREIN
.PREVIOUS DISCUSSION...
335 AM CST
SYNOPSIS...LIGHT SNOW IS POSSIBLE THIS AFTERNOON ALONG THE IL/WI
STATE LINE...THEN THE WARM UP IS ON THROUGH SATURDAY. TEMPS CRASH
BEHIND THE LOW SUNDAY WITH VERY COLD AIR RETURNING TO THE REGION.
SNOW IS POSSIBLE ON SUNDAY BUT THE BETTER CHANCE LOOKS TO BE MONDAY
NIGHT INTO TUESDAY.
TODAY AND TONIGHT...
THE UPPER LEVEL TROUGH AXIS HAS PUSHED EAST OF THE AREA ALONG WITH
THE SNOW WE SAW LAST NIGHT. AT THE SURFACE...WEAK LOW PRESSURE IS
OVER SOUTHWESTERN ONTARIO. HIGH PRESSURE IS CENTERED OVER TEXARKANA
BUT ITS RIDGE EXTENDS NORTH THROUGH THE MISSISSIPPI RIVER VALLEY.
THE RIDGE WILL MOVE OVERHEAD THIS MORNING WHILE THE MAIN HIGH
REMAINS TO OUR SOUTH.
A WEAK SHORTWAVE PASSES THROUGH WI THIS AFTN KICKING OFF SNOW
SHOWERS. THE MAIN VORT WILL BE OVER CENTRAL WI SO THINKING THE
MAJORITY OF PRECIP WILL BE OVER WI...BUT COULD SEE A HALF INCH OR
LESS ALONG THE IL/WI STATE LINE. MODEL SOUNDINGS SUPPORT THIS AS
THEY SHOW OMEGA REMAINING LOWER THAN THE SATURATED DGZ LAYER. THEN
AS OMEGA LIFTS INTO THE SATURATED LAYER...THE OMEGA WEAKENS GREATLY
AND THE SATURATION ALSO WEAKENS.
WINDS TURN SW AND WEAK WAA WILL LEAD TO HIGH TEMPS IN THE MID TO
UPPER 20S. FAR SOUTHERN AREAS IN THE CWA MAY EVEN MAKE OR BREAK
FREEZING AS THEY DO NOT HAVE ANY SNOW ON THE GROUND AND WILL SEE
SOME SUN. WAA CONTINUES THROUGH TONIGHT...BUT THE SNOWPACK WILL
WREAK HAVOC WITH LOW TEMPS. WINDS LIGHTEN DUE TO THE BAGGY PRESSURE
PATTERN AND CLOUDS THIN OVERNIGHT. THE GOING LOW TEMPS LOOKED VERY
REASONABLE...THEREFORE DID NOT MAKE ANY MAJOR CHANGES. HAVE TEENS
OVER NORTH CENTRAL IL AND THEN LOW 20S IN THE SOUTHEAST CORNER OF
THE CWA.
FRIDAY AND SATURDAY...
UPPER LEVEL FLOW TURNS ZONAL THROUGH SATURDAY AND WAA REALLY KICKS
INTO HIGH GEAR FRIDAY AND SATURDAY. A LOW PASSES WELL TO OUR
NORTH...BUT WITH THE HIGH OVER THE GULF COAST...THE PRESSURE
GRADIENT TIGHTENS AND WINDS PICK UP. SW WINDS AROUND 10 KT WITH
GUSTS 15 TO 20 KT WILL HELP USHER IN THE WARMER AIR. GUIDANCE HAS
925MB TEMPS RISING TO +4C BY FRIDAY EVENING AND THEN TO +6 TO +8 BY
SATURDAY EVENING. AS SUCH RAISED TEMPS FRIDAY...FRIDAY NIGHT...AND
SATURDAY. CONFIDENCE IS MEDIUM-HIGH IN THE GOING FORECAST TEMPS FOR
THAT PERIOD.
FOR NOW CONTINUED THE TREND THAT THE END OF THIS WEEK LOOKS ABOVE
NORMAL IN THE TEMP DEPARTMENT. HOW WARM...NOT SURE. FOR AREAS WITH
LITTLE SNOW...ROUGHLY AREAS ALONG AND SOUTH OF I-88...THE WARM UP
COULD BE WARMER THAN CURRENTLY FORECAST. FOR NOW THINKING ABOVE
FREEZING ON FRIDAY AND 40S ON SATURDAY SEEM REASONABLE. FOR AREAS
NORTH OF I-88 THAT HAVE A DECENT SNOW PACK...THINGS COULD BE MORE
DICEY. RFD FOR INSTANCE HAS 7 INCHES OF SNOW ON THE GROUND...AND
THE WAA ADVECTION AND NEAR FREEZING TEMPS ON FRIDAY MAY NOT MAKE A
SIGNIFICANT DENT IN THE SNOW. AS SUCH WENT NEAR GUIDANCE FOR
THESE NORTHERN AREAS WITH TEMPS JUST ABOVE FREEZING FRIDAY...AND
AROUND 40 SATURDAY. COULD CERTAINLY SEE A TIGHT TEMP GRADIENT
WITHIN THE CWA AS THE SNOW FREE AREAS WARM QUICKLY...WHILE THE AREAS
WITH SNOW PACK STRUGGLE TO CLIMB.
EXTENDED...SUNDAY THROUGH TUESDAY...
THE SURFACE LOW SINKS SOUTH...MOVING OVER THE CWA SATURDAY NIGHT
INTO SUNDAY. AN UPPER LEVEL STREAMER ASSOCIATED WITH THE LOW
WEAKENS AS THE STRONGER UPPER LEVEL TROUGH CATCHES UP WITH THE LOW.
PRECIP IS EXPECTED ALONG AND BEHIND THE COLD FRONT. GUIDANCE
DIFFERS A BIT ON THE TIMING OF THE LOW AND AS TO HOW MUCH FORCING
WILL ACCOMPANY IT. THE GFS IS MORE VIGOROUS THAN THE ECMWF WITH
PRECIP...WHILE THE ECMWF IS A BIT FASTER. AS SUCH LEFT POPS IN THE
CHANCE RANGE UNTIL THE FORCING AND TIMING ASPECTS BECOME A BIT
CLEARER. OVERALL NOT EXPECTING A LOT OF PRECIP/SNOW.
THE BIGGER STORY WILL BE TEMPS. TEMPS WILL FALL SUNDAY AS COLD AIR
CONTINUES TO FUNNEL IN BEHIND THE TROUGH AXIS. 925MB TEMPS FALL TO
-4 TO -14C ALOFT BY SUNDAY EVENING WITH COLDER AIR EXPECTED
OVERNIGHT. HIGH PRESSURE ALSO APPROACHES FROM THE WEST SO CLEARING
SKIES AND NORTHWEST WINDS AROUND 10 KT WILL LEAD TO A VERY COLD
NIGHT. LOW TEMPS WILL RANGE FROM BELOW ZERO OVER NORTH CENTRAL IL TO
SINGLE DIGITS OVER NW INDIANA. MIN WIND CHILLS BELOW -20 ARE STILL
EXPECTED ACROSS NORTH CENTRAL IL SUNDAY NIGHT AND MONDAY NIGHT.
COLD CONTINUES THROUGH NEW YEARS EVE WITH A SLIGHT RELIEF EXPECTED
ON JAN 1ST. GUIDANCE CONTINUES TO HINT AT A PRECIP SYSTEM
TUESDAY...BUT GUIDANCE IS LESS CLEAR ON FORCING AND TIMING TODAY
COMPARED TO YESTERDAY. THEREFORE LEFT SLIGHT CHANCE TO CHANCE POPS
IN THROUGH MID WEEK.
JEE
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 20Z...
* LIGHT SNOW/FLURRIES LATE THIS AFTERNOON AND EARLY EVENING.
* CIG TRENDS...AND POTENTIAL FOR MVFR TO RETURN THIS EVENING AND
OVERNIGHT.
BMD
//DISCUSSION...UPDATED 18Z...
BAND OF SNOW IS EXITING EAST OF THIS CHICAGO TERMINALS THIS
AFTERNOON BUT A PAIR OF ADDITIONAL UPPER LEVEL DISTURBANCES TO THE
NORTHWEST WILL BRING ADDITIONAL CHANCES FOR SNOW THROUGH PORTIONS
OF THE AFTERNOON AND EVENING. THE FIRST WAVE IS CURRENTLY
DROPPING SOUTHEAST ACROSS IOWA WITH RADAR RETURNS ACROSS MUCH OF
THE EASTERN HALF OF IOWA AND NORTHWEST ILLINOIS. PER SURFACE OBS
HOWEVER...MOST OF THIS IS NOT REACHING THE GROUND...AND APPEARS
THE MAIN FORCING WILL DROP SOUTH OF THE TERMINALS EARLY THIS
AFTERNOON. THE NEXT WAVE IS OVER THE EASTERN DAKOTAS EARLY THIS
AFTERNOON AND WILL TAKE AIM AT THE IL/WI STATE LINE LATE THIS
AFTERNOON AND THIS EVENING. MOST MODELS INDICATE THAT THE
ACCUMULATING SNOWFALL WILL FALL NORTH OF THE TERMINALS...HOWEVER
SOME LIFT IS NOTED AS FAR SOUTH AS THE TERMINALS. ITS NOT CO-
LOCATED WELL WITH THE MOISTURE OR THE SNOW GROWTH ZONE...SO DO NOT
ANTICIPATE EFFICIENT SNOW PRODUCTION WITH THIS WAVE.
INSTEAD...EXPECT A PERIOD OF FLURRIES WITH GENERALLY VFR
CONDITIONS...THOUGH CANNOT RULE OUT PERHAPS A PERIODIC BRIEF DROPS
TO MVFR VSBY. WILL MONITOR UPSTREAM TRENDS THIS AFTERNOON TO
DETERMINE IF THE THREAT IS ENOUGH TO INCLUDE IN TAF.
THERE IS A WEAK SURFACE REFLECTION OF THE SECOND WAVE THIS EVENING.
SSW TO SW WINDS AHEAD OF THE SURFACE TROUGH WILL VEER TO THE WSW OR
WEST FOR A PERIOD THIS EVENING. BEHIND THIS SLIGHT WIND
SHIFT...FORECAST SOUNDINGS SHOW SATURATION OF THE LOWER LEVELS
INDICATING THE DEVELOPMENT OF MVFR OR IN SOME CASES IFR CIGS. MET
GUIDANCE INDICATES A SIMILAR DROP IN CIGS OVERNIGHT...WHILE MAV/LAV
GUIDANCE DOES NOT. WILL INTRODUCE MVFR CIGS INTO THE FORECAST...BUT
AM CONCERNED THAT LOWER CIGS ARE POSSIBLE. RAP LOW LEVEL MOISTURE
FIELDS INDICATE THESE CIGS WILL DEVELOP NEAR THE MISSISSIPPI RIVER
MID TO LATE THIS AFTERNOON...SO WILL GAIN MORE CONFIDENCE IN CIG
TRENDS BY THEN.
BMD
//ORD AND MDW CONFIDENCE...UPDATED 20Z...
* MEDIUM CONFIDENCE IN PRECIP/VSBY TRENDS.
* MEDIUM CONFIDENCE IN CIG TRENDS THROUGH THE AFTERNOON...THEN LOW
CONFIDENCE THIS EVENING/OVERNIGHT.
BMD
//OUTLOOK FOR ORD/MDW FOR 00Z SATURDAY-12Z THURSDAY...UPDATED 12Z...
FRIDAY NIGHT...VFR WIND.
SATURDAY...VFR WIND.
SUNDAY THROUGH TUESDAY NIGHT...PERIODS OF -SN WITH OCNL MVFR
CIGS/VSBY. A PERIOD OF IFR CIGS/VIS POSSIBLE.
WEDNESDAY...VFR WX NIL.
ED F
&&
.MARINE...
327 AM CST
AN ACTIVE PERIOD ON LAKE MICHIGAN WEATHER WISE ON TAP FOR THE
NEXT 5 DAYS AS THE AREA REMAINS UNDER THE INFLUENCE OF FAST
NORTHWEST FLOW ALOFT THAT BECOMES ZONAL BRIEFLY FRIDAY-SATURDAY.
THIS WILL SET THE STAGE FOR A COUPLE OF SEPARATE SYSTEMS TO
POSSIBLY PRODUCE MULTIPLE PERIODS OF GALE FORCE WINDS FRIDAY
THROUGH SUNDAY. LOW PRESSURE DEPARTING THE AREA TODAY WILL BE
REPLACED WITH A RIDGE AXIS SLIDING EAST ACROSS THE LAKE THIS
EVENING. LOW PRESSURE WILL THEN MOVE OUT OF SASKATCHEWAN TO
NORTHERN LAKE SUPERIOR BY FRIDAY EVENING. THE STRONG PRESSURE
CONTRAST BETWEEN THIS LOW AND HIGH PRESSURE TO THE SOUTHEAST WILL
LIKELY RESULT IN GALE FORCE WINDS FOR A PERIOD LATE FRIDAY/FRIDAY
NIGHT.
UNCERTAINTY SURROUNDING A SECOND AREA OF LOW PRESSURE POTENTIALLY
STRONGER MOVING OUT OF THE PLAINS AND INTO THE WESTERN GREAT LAKES
BY EARLY SUNDAY WILL SET THE STAGE FOR ADDITIONAL PERIODS OF GALES
POSSIBLY SATURDAY AND SUNDAY DEPENDING ON HOW EXACTLY THIS LOW
EVOLVES. AT THE SAME TIME WINDS CLOSER TO THE TRACK OF THE LOW
ITSELF WILL BE LIGHTER. MOST ANY FORECAST BUT THIS ONE IN
PARTICULAR WILL BE BEST MONITORED VIA THE GRAPHICAL FORECASTS
AVAILABLE ON THE WEB AT WWW.WEATHER.GOV/GREATLAKES IN ORDER TO SEE
THE RICHNESS OF THE DETAIL EXPECTED GIVEN THIS COMPLEX SITUATION.
ED F
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...GALE WATCH...LMZ261-LMZ362-LMZ364-LMZ366-LMZ563-LMZ565-LMZ567-
LMZ868...NOON FRIDAY TO MIDNIGHT SATURDAY.
&&
$$
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
1202 PM CST THU DEC 26 2013
.DISCUSSION...
930 AM CST
HAVE MADE SOME MINOR ADJUSTMENTS TO THE WX/POP/QPS FOR THE REST OF
THIS MORNING AND INTO THIS AFTERNOON. A SERIES OF SHORTWAVES
RIPPLING THROUGH THE FAST NORTHWEST FLOW ALOFT ARE ALREADY
GENERATING SOME LIGHT SNOW ACROSS NRN IL. THE LATEST GUIDANCE AND
UPSTREAM SATELLITE IMAGERY SUGGEST THAT A COUPLE MORE ORGANIZED
SHORTWAVES WILL TRAVERSE THE NRN PORTIONS OF THE CWA THIS
AFTERNOON. SO HAVE BUMPED UP POPS FOR THE REMAINDER OF TODAY.
WHILE THIS LOOKS TO BE MORE OF A HIGHER POP...LOWER QPF
SITUATION...WILL STILL CARRY MEASURABLE PCPN FOR THIS AFTERNOON...
BUT GIVEN THE EXPECTATIONS OF RELATIVELY HIGH SNOW TO LIQUID RATIO
LIKELY...ANY SNOWFALL WOULD MOST LIKELY BE OBSERVED AS A DUSTING
AND DIFFICULT TO ACTUALLY MEASURE.
KREIN
.PREVIOUS DISCUSSION...
335 AM CST
SYNOPSIS...LIGHT SNOW IS POSSIBLE THIS AFTERNOON ALONG THE IL/WI
STATE LINE...THEN THE WARM UP IS ON THROUGH SATURDAY. TEMPS CRASH
BEHIND THE LOW SUNDAY WITH VERY COLD AIR RETURNING TO THE REGION.
SNOW IS POSSIBLE ON SUNDAY BUT THE BETTER CHANCE LOOKS TO BE MONDAY
NIGHT INTO TUESDAY.
TODAY AND TONIGHT...
THE UPPER LEVEL TROUGH AXIS HAS PUSHED EAST OF THE AREA ALONG WITH
THE SNOW WE SAW LAST NIGHT. AT THE SURFACE...WEAK LOW PRESSURE IS
OVER SOUTHWESTERN ONTARIO. HIGH PRESSURE IS CENTERED OVER TEXARKANA
BUT ITS RIDGE EXTENDS NORTH THROUGH THE MISSISSIPPI RIVER VALLEY.
THE RIDGE WILL MOVE OVERHEAD THIS MORNING WHILE THE MAIN HIGH
REMAINS TO OUR SOUTH.
A WEAK SHORTWAVE PASSES THROUGH WI THIS AFTN KICKING OFF SNOW
SHOWERS. THE MAIN VORT WILL BE OVER CENTRAL WI SO THINKING THE
MAJORITY OF PRECIP WILL BE OVER WI...BUT COULD SEE A HALF INCH OR
LESS ALONG THE IL/WI STATE LINE. MODEL SOUNDINGS SUPPORT THIS AS
THEY SHOW OMEGA REMAINING LOWER THAN THE SATURATED DGZ LAYER. THEN
AS OMEGA LIFTS INTO THE SATURATED LAYER...THE OMEGA WEAKENS GREATLY
AND THE SATURATION ALSO WEAKENS.
WINDS TURN SW AND WEAK WAA WILL LEAD TO HIGH TEMPS IN THE MID TO
UPPER 20S. FAR SOUTHERN AREAS IN THE CWA MAY EVEN MAKE OR BREAK
FREEZING AS THEY DO NOT HAVE ANY SNOW ON THE GROUND AND WILL SEE
SOME SUN. WAA CONTINUES THROUGH TONIGHT...BUT THE SNOWPACK WILL
WREAK HAVOC WITH LOW TEMPS. WINDS LIGHTEN DUE TO THE BAGGY PRESSURE
PATTERN AND CLOUDS THIN OVERNIGHT. THE GOING LOW TEMPS LOOKED VERY
REASONABLE...THEREFORE DID NOT MAKE ANY MAJOR CHANGES. HAVE TEENS
OVER NORTH CENTRAL IL AND THEN LOW 20S IN THE SOUTHEAST CORNER OF
THE CWA.
FRIDAY AND SATURDAY...
UPPER LEVEL FLOW TURNS ZONAL THROUGH SATURDAY AND WAA REALLY KICKS
INTO HIGH GEAR FRIDAY AND SATURDAY. A LOW PASSES WELL TO OUR
NORTH...BUT WITH THE HIGH OVER THE GULF COAST...THE PRESSURE
GRADIENT TIGHTENS AND WINDS PICK UP. SW WINDS AROUND 10 KT WITH
GUSTS 15 TO 20 KT WILL HELP USHER IN THE WARMER AIR. GUIDANCE HAS
925MB TEMPS RISING TO +4C BY FRIDAY EVENING AND THEN TO +6 TO +8 BY
SATURDAY EVENING. AS SUCH RAISED TEMPS FRIDAY...FRIDAY NIGHT...AND
SATURDAY. CONFIDENCE IS MEDIUM-HIGH IN THE GOING FORECAST TEMPS FOR
THAT PERIOD.
FOR NOW CONTINUED THE TREND THAT THE END OF THIS WEEK LOOKS ABOVE
NORMAL IN THE TEMP DEPARTMENT. HOW WARM...NOT SURE. FOR AREAS WITH
LITTLE SNOW...ROUGHLY AREAS ALONG AND SOUTH OF I-88...THE WARM UP
COULD BE WARMER THAN CURRENTLY FORECAST. FOR NOW THINKING ABOVE
FREEZING ON FRIDAY AND 40S ON SATURDAY SEEM REASONABLE. FOR AREAS
NORTH OF I-88 THAT HAVE A DECENT SNOW PACK...THINGS COULD BE MORE
DICEY. RFD FOR INSTANCE HAS 7 INCHES OF SNOW ON THE GROUND...AND
THE WAA ADVECTION AND NEAR FREEZING TEMPS ON FRIDAY MAY NOT MAKE A
SIGNIFICANT DENT IN THE SNOW. AS SUCH WENT NEAR GUIDANCE FOR
THESE NORTHERN AREAS WITH TEMPS JUST ABOVE FREEZING FRIDAY...AND
AROUND 40 SATURDAY. COULD CERTAINLY SEE A TIGHT TEMP GRADIENT
WITHIN THE CWA AS THE SNOW FREE AREAS WARM QUICKLY...WHILE THE AREAS
WITH SNOW PACK STRUGGLE TO CLIMB.
EXTENDED...SUNDAY THROUGH TUESDAY...
THE SURFACE LOW SINKS SOUTH...MOVING OVER THE CWA SATURDAY NIGHT
INTO SUNDAY. AN UPPER LEVEL STREAMER ASSOCIATED WITH THE LOW
WEAKENS AS THE STRONGER UPPER LEVEL TROUGH CATCHES UP WITH THE LOW.
PRECIP IS EXPECTED ALONG AND BEHIND THE COLD FRONT. GUIDANCE
DIFFERS A BIT ON THE TIMING OF THE LOW AND AS TO HOW MUCH FORCING
WILL ACCOMPANY IT. THE GFS IS MORE VIGOROUS THAN THE ECMWF WITH
PRECIP...WHILE THE ECMWF IS A BIT FASTER. AS SUCH LEFT POPS IN THE
CHANCE RANGE UNTIL THE FORCING AND TIMING ASPECTS BECOME A BIT
CLEARER. OVERALL NOT EXPECTING A LOT OF PRECIP/SNOW.
THE BIGGER STORY WILL BE TEMPS. TEMPS WILL FALL SUNDAY AS COLD AIR
CONTINUES TO FUNNEL IN BEHIND THE TROUGH AXIS. 925MB TEMPS FALL TO
-4 TO -14C ALOFT BY SUNDAY EVENING WITH COLDER AIR EXPECTED
OVERNIGHT. HIGH PRESSURE ALSO APPROACHES FROM THE WEST SO CLEARING
SKIES AND NORTHWEST WINDS AROUND 10 KT WILL LEAD TO A VERY COLD
NIGHT. LOW TEMPS WILL RANGE FROM BELOW ZERO OVER NORTH CENTRAL IL TO
SINGLE DIGITS OVER NW INDIANA. MIN WIND CHILLS BELOW -20 ARE STILL
EXPECTED ACROSS NORTH CENTRAL IL SUNDAY NIGHT AND MONDAY NIGHT.
COLD CONTINUES THROUGH NEW YEARS EVE WITH A SLIGHT RELIEF EXPECTED
ON JAN 1ST. GUIDANCE CONTINUES TO HINT AT A PRECIP SYSTEM
TUESDAY...BUT GUIDANCE IS LESS CLEAR ON FORCING AND TIMING TODAY
COMPARED TO YESTERDAY. THEREFORE LEFT SLIGHT CHANCE TO CHANCE POPS
IN THROUGH MID WEEK.
JEE
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 18Z...
* LIGHT SNOW/FLURRIES LATE THIS AFTERNOON AND EARLY EVENING.
* CIG TRENDS...AND POTENTIAL FOR MVFR TO RETURN THIS EVENING AND
OVERNIGHT.
BMD
//DISCUSSION...UPDATED 18Z...
BAND OF SNOW IS EXITING EAST OF THIS CHICAGO TERMINALS THIS
AFTERNOON BUT A PAIR OF ADDITIONAL UPPER LEVEL DISTURBANCES TO THE
NORTHWEST WILL BRING ADDITIONAL CHANCES FOR SNOW THROUGH PORTIONS
OF THE AFTERNOON AND EVENING. THE FIRST WAVE IS CURRENTLY
DROPPING SOUTHEAST ACROSS IOWA WITH RADAR RETURNS ACROSS MUCH OF
THE EASTERN HALF OF IOWA AND NORTHWEST ILLINOIS. PER SURFACE OBS
HOWEVER...MOST OF THIS IS NOT REACHING THE GROUND...AND APPEARS
THE MAIN FORCING WILL DROP SOUTH OF THE TERMINALS EARLY THIS
AFTERNOON. THE NEXT WAVE IS OVER THE EASTERN DAKOTAS EARLY THIS
AFTERNOON AND WILL TAKE AIM AT THE IL/WI STATE LINE LATE THIS
AFTERNOON AND THIS EVENING. MOST MODELS INDICATE THAT THE
ACCUMULATING SNOWFALL WILL FALL NORTH OF THE TERMINALS...HOWEVER
SOME LIFT IS NOTED AS FAR SOUTH AS THE TERMINALS. ITS NOT CO-
LOCATED WELL WITH THE MOISTURE OR THE SNOW GROWTH ZONE...SO DO NOT
ANTICIPATE EFFICIENT SNOW PRODUCTION WITH THIS WAVE.
INSTEAD...EXPECT A PERIOD OF FLURRIES WITH GENERALLY VFR
CONDITIONS...THOUGH CANNOT RULE OUT PERHAPS A PERIODIC BRIEF DROPS
TO MVFR VSBY. WILL MONITOR UPSTREAM TRENDS THIS AFTERNOON TO
DETERMINE IF THE THREAT IS ENOUGH TO INCLUDE IN TAF.
THERE IS A WEAK SURFACE REFLECTION OF THE SECOND WAVE THIS EVENING.
SSW TO SW WINDS AHEAD OF THE SURFACE TROUGH WILL VEER TO THE WSW OR
WEST FOR A PERIOD THIS EVENING. BEHIND THIS SLIGHT WIND
SHIFT...FORECAST SOUNDINGS SHOW SATURATION OF THE LOWER LEVELS
INDICATING THE DEVELOPMENT OF MVFR OR IN SOME CASES IFR CIGS. MET
GUIDANCE INDICATES A SIMILAR DROP IN CIGS OVERNIGHT...WHILE MAV/LAV
GUIDANCE DOES NOT. WILL INTRODUCE MVFR CIGS INTO THE FORECAST...BUT
AM CONCERNED THAT LOWER CIGS ARE POSSIBLE. RAP LOW LEVEL MOISTURE
FIELDS INDICATE THESE CIGS WILL DEVELOP NEAR THE MISSISSIPPI RIVER
MID TO LATE THIS AFTERNOON...SO WILL GAIN MORE CONFIDENCE IN CIG
TRENDS BY THEN.
BMD
//ORD AND MDW CONFIDENCE...UPDATED 18Z...
* MEDIUM CONFIDENCE IN PRECIP/VSBY TRENDS.
* MEDIUM CONFIDENCE IN CIG TRENDS THROUGH THE AFTERNOON...THEN LOW
CONFIDENCE THIS EVENING/OVERNIGHT.
BMD
//OUTLOOK FOR ORD/MDW FOR 00Z SATURDAY-12Z THURSDAY...UPDATED 12Z...
FRIDAY NIGHT...VFR WIND.
SATURDAY...VFR WIND.
SUNDAY THROUGH TUESDAY NIGHT...PERIODS OF -SN WITH OCNL MVFR
CIGS/VSBY. A PERIOD OF IFR CIGS/VIS POSSIBLE.
WEDNESDAY...VFR WX NIL.
ED F
&&
.MARINE...
327 AM CST
AN ACTIVE PERIOD ON LAKE MICHIGAN WEATHER WISE ON TAP FOR THE
NEXT 5 DAYS AS THE AREA REMAINS UNDER THE INFLUENCE OF FAST
NORTHWEST FLOW ALOFT THAT BECOMES ZONAL BRIEFLY FRIDAY-SATURDAY.
THIS WILL SET THE STAGE FOR A COUPLE OF SEPARATE SYSTEMS TO
POSSIBLY PRODUCE MULTIPLE PERIODS OF GALE FORCE WINDS FRIDAY
THROUGH SUNDAY. LOW PRESSURE DEPARTING THE AREA TODAY WILL BE
REPLACED WITH A RIDGE AXIS SLIDING EAST ACROSS THE LAKE THIS
EVENING. LOW PRESSURE WILL THEN MOVE OUT OF SASKATCHEWAN TO
NORTHERN LAKE SUPERIOR BY FRIDAY EVENING. THE STRONG PRESSURE
CONTRAST BETWEEN THIS LOW AND HIGH PRESSURE TO THE SOUTHEAST WILL
LIKELY RESULT IN GALE FORCE WINDS FOR A PERIOD LATE FRIDAY/FRIDAY
NIGHT.
UNCERTAINTY SURROUNDING A SECOND AREA OF LOW PRESSURE POTENTIALLY
STRONGER MOVING OUT OF THE PLAINS AND INTO THE WESTERN GREAT LAKES
BY EARLY SUNDAY WILL SET THE STAGE FOR ADDITIONAL PERIODS OF GALES
POSSIBLY SATURDAY AND SUNDAY DEPENDING ON HOW EXACTLY THIS LOW
EVOLVES. AT THE SAME TIME WINDS CLOSER TO THE TRACK OF THE LOW
ITSELF WILL BE LIGHTER. MOST ANY FORECAST BUT THIS ONE IN
PARTICULAR WILL BE BEST MONITORED VIA THE GRAPHICAL FORECASTS
AVAILABLE ON THE WEB AT WWW.WEATHER.GOV/GREATLAKES IN ORDER TO SEE
THE RICHNESS OF THE DETAIL EXPECTED GIVEN THIS COMPLEX SITUATION.
ED F
&&
.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
1007 AM CST THU DEC 26 2013
.DISCUSSION...
930 AM CST
HAVE MADE SOME MINOR ADJUSTMENTS TO THE WX/POP/QPS FOR THE REST OF
THIS MORNING AND INTO THIS AFTERNOON. A SERIES OF SHORTWAVES
RIPPLING THROUGH THE FAST NORTHWEST FLOW ALOFT ARE ALREADY
GENERATING SOME LIGHT SNOW ACROSS NRN IL. THE LATEST GUIDANCE AND
UPSTREAM SATELLITE IMAGERY SUGGEST THAT A COUPLE MORE ORGANIZED
SHORTWAVES WILL TRAVERSE THE NRN PORTIONS OF THE CWA THIS
AFTERNOON. SO HAVE BUMPED UP POPS FOR THE REMAINDER OF TODAY.
WHILE THIS LOOKS TO BE MORE OF A HIGHER POP...LOWER QPF
SITUATION...WILL STILL CARRY MEASURABLE PCPN FOR THIS AFTERNOON...
BUT GIVEN THE EXPECTATIONS OF RELATIVELY HIGH SNOW TO LIQUID RATIO
LIKELY...ANY SNOWFALL WOULD MOST LIKELY BE OBSERVED AS A DUSTING
AND DIFFICULT TO ACTUALLY MEASURE.
KREIN
.PREVIOUS DISCUSSION...
335 AM CST
SYNOPSIS...LIGHT SNOW IS POSSIBLE THIS AFTERNOON ALONG THE IL/WI
STATE LINE...THEN THE WARM UP IS ON THROUGH SATURDAY. TEMPS CRASH
BEHIND THE LOW SUNDAY WITH VERY COLD AIR RETURNING TO THE REGION.
SNOW IS POSSIBLE ON SUNDAY BUT THE BETTER CHANCE LOOKS TO BE MONDAY
NIGHT INTO TUESDAY.
TODAY AND TONIGHT...
THE UPPER LEVEL TROUGH AXIS HAS PUSHED EAST OF THE AREA ALONG WITH
THE SNOW WE SAW LAST NIGHT. AT THE SURFACE...WEAK LOW PRESSURE IS
OVER SOUTHWESTERN ONTARIO. HIGH PRESSURE IS CENTERED OVER TEXARKANA
BUT ITS RIDGE EXTENDS NORTH THROUGH THE MISSISSIPPI RIVER VALLEY.
THE RIDGE WILL MOVE OVERHEAD THIS MORNING WHILE THE MAIN HIGH
REMAINS TO OUR SOUTH.
A WEAK SHORTWAVE PASSES THROUGH WI THIS AFTN KICKING OFF SNOW
SHOWERS. THE MAIN VORT WILL BE OVER CENTRAL WI SO THINKING THE
MAJORITY OF PRECIP WILL BE OVER WI...BUT COULD SEE A HALF INCH OR
LESS ALONG THE IL/WI STATE LINE. MODEL SOUNDINGS SUPPORT THIS AS
THEY SHOW OMEGA REMAINING LOWER THAN THE SATURATED DGZ LAYER. THEN
AS OMEGA LIFTS INTO THE SATURATED LAYER...THE OMEGA WEAKENS GREATLY
AND THE SATURATION ALSO WEAKENS.
WINDS TURN SW AND WEAK WAA WILL LEAD TO HIGH TEMPS IN THE MID TO
UPPER 20S. FAR SOUTHERN AREAS IN THE CWA MAY EVEN MAKE OR BREAK
FREEZING AS THEY DO NOT HAVE ANY SNOW ON THE GROUND AND WILL SEE
SOME SUN. WAA CONTINUES THROUGH TONIGHT...BUT THE SNOWPACK WILL
WREAK HAVOC WITH LOW TEMPS. WINDS LIGHTEN DUE TO THE BAGGY PRESSURE
PATTERN AND CLOUDS THIN OVERNIGHT. THE GOING LOW TEMPS LOOKED VERY
REASONABLE...THEREFORE DID NOT MAKE ANY MAJOR CHANGES. HAVE TEENS
OVER NORTH CENTRAL IL AND THEN LOW 20S IN THE SOUTHEAST CORNER OF
THE CWA.
FRIDAY AND SATURDAY...
UPPER LEVEL FLOW TURNS ZONAL THROUGH SATURDAY AND WAA REALLY KICKS
INTO HIGH GEAR FRIDAY AND SATURDAY. A LOW PASSES WELL TO OUR
NORTH...BUT WITH THE HIGH OVER THE GULF COAST...THE PRESSURE
GRADIENT TIGHTENS AND WINDS PICK UP. SW WINDS AROUND 10 KT WITH
GUSTS 15 TO 20 KT WILL HELP USHER IN THE WARMER AIR. GUIDANCE HAS
925MB TEMPS RISING TO +4C BY FRIDAY EVENING AND THEN TO +6 TO +8 BY
SATURDAY EVENING. AS SUCH RAISED TEMPS FRIDAY...FRIDAY NIGHT...AND
SATURDAY. CONFIDENCE IS MEDIUM-HIGH IN THE GOING FORECAST TEMPS FOR
THAT PERIOD.
FOR NOW CONTINUED THE TREND THAT THE END OF THIS WEEK LOOKS ABOVE
NORMAL IN THE TEMP DEPARTMENT. HOW WARM...NOT SURE. FOR AREAS WITH
LITTLE SNOW...ROUGHLY AREAS ALONG AND SOUTH OF I-88...THE WARM UP
COULD BE WARMER THAN CURRENTLY FORECAST. FOR NOW THINKING ABOVE
FREEZING ON FRIDAY AND 40S ON SATURDAY SEEM REASONABLE. FOR AREAS
NORTH OF I-88 THAT HAVE A DECENT SNOW PACK...THINGS COULD BE MORE
DICEY. RFD FOR INSTANCE HAS 7 INCHES OF SNOW ON THE GROUND...AND
THE WAA ADVECTION AND NEAR FREEZING TEMPS ON FRIDAY MAY NOT MAKE A
SIGNIFICANT DENT IN THE SNOW. AS SUCH WENT NEAR GUIDANCE FOR
THESE NORTHERN AREAS WITH TEMPS JUST ABOVE FREEZING FRIDAY...AND
AROUND 40 SATURDAY. COULD CERTAINLY SEE A TIGHT TEMP GRADIENT
WITHIN THE CWA AS THE SNOW FREE AREAS WARM QUICKLY...WHILE THE AREAS
WITH SNOW PACK STRUGGLE TO CLIMB.
EXTENDED...SUNDAY THROUGH TUESDAY...
THE SURFACE LOW SINKS SOUTH...MOVING OVER THE CWA SATURDAY NIGHT
INTO SUNDAY. AN UPPER LEVEL STREAMER ASSOCIATED WITH THE LOW
WEAKENS AS THE STRONGER UPPER LEVEL TROUGH CATCHES UP WITH THE LOW.
PRECIP IS EXPECTED ALONG AND BEHIND THE COLD FRONT. GUIDANCE
DIFFERS A BIT ON THE TIMING OF THE LOW AND AS TO HOW MUCH FORCING
WILL ACCOMPANY IT. THE GFS IS MORE VIGOROUS THAN THE ECMWF WITH
PRECIP...WHILE THE ECMWF IS A BIT FASTER. AS SUCH LEFT POPS IN THE
CHANCE RANGE UNTIL THE FORCING AND TIMING ASPECTS BECOME A BIT
CLEARER. OVERALL NOT EXPECTING A LOT OF PRECIP/SNOW.
THE BIGGER STORY WILL BE TEMPS. TEMPS WILL FALL SUNDAY AS COLD AIR
CONTINUES TO FUNNEL IN BEHIND THE TROUGH AXIS. 925MB TEMPS FALL TO
-4 TO -14C ALOFT BY SUNDAY EVENING WITH COLDER AIR EXPECTED
OVERNIGHT. HIGH PRESSURE ALSO APPROACHES FROM THE WEST SO CLEARING
SKIES AND NORTHWEST WINDS AROUND 10 KT WILL LEAD TO A VERY COLD
NIGHT. LOW TEMPS WILL RANGE FROM BELOW ZERO OVER NORTH CENTRAL IL TO
SINGLE DIGITS OVER NW INDIANA. MIN WIND CHILLS BELOW -20 ARE STILL
EXPECTED ACROSS NORTH CENTRAL IL SUNDAY NIGHT AND MONDAY NIGHT.
COLD CONTINUES THROUGH NEW YEARS EVE WITH A SLIGHT RELIEF EXPECTED
ON JAN 1ST. GUIDANCE CONTINUES TO HINT AT A PRECIP SYSTEM
TUESDAY...BUT GUIDANCE IS LESS CLEAR ON FORCING AND TIMING TODAY
COMPARED TO YESTERDAY. THEREFORE LEFT SLIGHT CHANCE TO CHANCE POPS
IN THROUGH MID WEEK.
JEE
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 16Z...
* BAND OF LIGHT SNOW/FLURRIES THIS MORNING...AND PERIODS OF MVFR
VSBY PSBL.
* TIMING OF NEXT CLIPPER SNOW STAYING NORTH OF ORD/MDW LATER
THIS AFTERNOON/EVENING (BUT NOT BY MUCH)
ED F/BMD
//DISCUSSION...UPDATED 12Z...
FAST NORTHWEST FLOW ALOFT CONTINUES TODAY WITH ANOTHER UPPER LEVEL
DISTURBANCE POISED TO PASS BY NORTH OF THE LOCAL AREA LATE THIS
AFTERNOON AND THIS EVENING. AREAS OF MID LEVEL CLOUDINESS
STREAMING ESE IN THIS FAST FLOW ALOFT AHEAD OF THIS DISTURBANCE
WILL MOVE ACROSS THE TERMINALS THIS MORNING AND AFTERNOON.
GOOD SIZED AREA OF 3000-4000 FT SC CLOUD DECK OVER IOWA EXPECTED
TO ALSO ADVECT INTO ILLINOIS THIS MORNING. MAY SEE CIGS BRIEFLY GO
BELOW 3000 FT WITH THIS CLOUD DECK.
WINDS HAVE SLACKENED FROM PRE-DAWN GUSTINESS AS MAX OF PRESSURE
RISES NOW OVERHEAD AND SLIDING OFF TO OUR EAST AND SURFACE RIDGE
AXIS APPROACHING. EXPECT WINDS TO REMAIN AROUND 10 KT OR LESS
REMAINDER OF THE DAY. AFOREMENTIONED UPPER DISTURBANCE WILL
ENHANCE CLOUDINESS LATE THIS AFTERNOON AND MAY BRING A PASSING
FLURRY. ANY ACCUMULATING SNOW IS EXPECTED TO STAY NORTH OF ORD/MDW
TONIGHT.
ED F
//ORD AND MDW CONFIDENCE...UPDATED 16Z...
* MEDIUM TO HIGH CONFIDENCE ON WIND TRENDS.
* LOW TO MEDIUM CONFIDENCE ON CLOUD TRENDS
* MEDIUM TO HIGH CONFIDENCE IN SNOW THIS MORNING WITH PERIODS OF
MVFR VSBY. MEDIUM CONFIDENCE THAT SNOW THAT WOULD RESTRICT
VISIBILITY WILL STAY NORTH OF ORD/MDW LATER THIS
AFTERNOON/EVENING.
ED F/BMD
//OUTLOOK FOR ORD/MDW FOR 00Z SATURDAY-12Z THURSDAY...UPDATED 12Z...
FRIDAY NIGHT...VFR WIND.
SATURDAY...VFR WIND.
SUNDAY THROUGH TUESDAY NIGHT...PERIODS OF -SN WITH OCNL MVFR
CIGS/VSBY. A PERIOD OF IFR CIGS/VIS POSSIBLE.
WEDNESDAY...VFR WX NIL.
ED F
&&
.MARINE...
327 AM CST
AN ACTIVE PERIOD ON LAKE MICHIGAN WEATHER WISE ON TAP FOR THE
NEXT 5 DAYS AS THE AREA REMAINS UNDER THE INFLUENCE OF FAST
NORTHWEST FLOW ALOFT THAT BECOMES ZONAL BRIEFLY FRIDAY-SATURDAY.
THIS WILL SET THE STAGE FOR A COUPLE OF SEPARATE SYSTEMS TO
POSSIBLY PRODUCE MULTIPLE PERIODS OF GALE FORCE WINDS FRIDAY
THROUGH SUNDAY. LOW PRESSURE DEPARTING THE AREA TODAY WILL BE
REPLACED WITH A RIDGE AXIS SLIDING EAST ACROSS THE LAKE THIS
EVENING. LOW PRESSURE WILL THEN MOVE OUT OF SASKATCHEWAN TO
NORTHERN LAKE SUPERIOR BY FRIDAY EVENING. THE STRONG PRESSURE
CONTRAST BETWEEN THIS LOW AND HIGH PRESSURE TO THE SOUTHEAST WILL
LIKELY RESULT IN GALE FORCE WINDS FOR A PERIOD LATE FRIDAY/FRIDAY
NIGHT.
UNCERTAINTY SURROUNDING A SECOND AREA OF LOW PRESSURE POTENTIALLY
STRONGER MOVING OUT OF THE PLAINS AND INTO THE WESTERN GREAT LAKES
BY EARLY SUNDAY WILL SET THE STAGE FOR ADDITIONAL PERIODS OF GALES
POSSIBLY SATURDAY AND SUNDAY DEPENDING ON HOW EXACTLY THIS LOW
EVOLVES. AT THE SAME TIME WINDS CLOSER TO THE TRACK OF THE LOW
ITSELF WILL BE LIGHTER. MOST ANY FORECAST BUT THIS ONE IN
PARTICULAR WILL BE BEST MONITORED VIA THE GRAPHICAL FORECASTS
AVAILABLE ON THE WEB AT WWW.WEATHER.GOV/GREATLAKES IN ORDER TO SEE
THE RICHNESS OF THE DETAIL EXPECTED GIVEN THIS COMPLEX SITUATION.
ED F
&&
.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
National Weather Service Lincoln IL
958 AM CST Thu Dec 26 2013
.DISCUSSION...
ISSUED 958 AM CST Thu Dec 26 2013
Lingering area of altocumulus clouds about to exit the northeast
CWA, however another batch covers most of Iowa and is headed
southeast. Latest RAP model shows this spreading over the northern
half of the forecast area this afternoon. Recent zone/grid updates
mainly were done to reflect the latest cloud trends. Temperatures
currently on track and required little change other than the usual
hourly trend tweaks.
Geelhart
&&
.AVIATION...
ISSUED 559 AM CST Thu Dec 26 2013
VFR conditions should continue over the next 24 hours, as clippers
pass by just to the north of the area. Those weather disturbances
will bring mainly mid-level clouds over our terminal sites today
and tonight. No precipitation is expected, due to the amount of
dry air in the lowest levels of the atmosphere.
Winds will begin from the west early this morning, then become
southwest as high surface pressure passes by to the south of IL
and low pressure moves across the upper Midwest. Pressure
gradients will support wind speeds increasing into the 10-14kt
range today, which will maintain for much of the evening before
dropping below 10kt later tonight.
Shimon
&&
.PREV DISCUSSION...
ISSUED 207 AM CST Thu Dec 26 2013
SHORT TERM...Today through Saturday
Next short-wave embedded within the progressive northwesterly flow
pattern is evident on 08z/2am water vapor imagery over southern
Saskatchewan/northern Montana. As has been advertised for the past
few model runs, this wave will remain a bit further north than the
previous ones. This will keep any light snow or flurries well to
the north across Wisconsin and far northern Illinois today, while
central Illinois only sees a few clouds. Latest IR satellite imagery
shows skies clearing out in the wake of the previous disturbance:
however, plenty of cloud cover is poised just upstream ahead of
the next wave. Based on satellite trajectories, it appears clouds
will overspread much of the central and northern KILX CWA, while
skies remain mostly clear further south. Will be a fairly mild day
as well, with southerly winds allowing temps to rise a degree or
two higher than yesterday, mainly reaching the middle 30s.
Once short-wave passes tonight, upper flow will briefly become
zonal Friday into Saturday, leading to a considerable warming
trend. With 850mb temps progged to reach the 6 to 8C range, high
temps will likely climb well into the 40s and perhaps even the
lower 50s across the southeast CWA on Saturday.
LONG TERM...Sunday through Wednesday
The warmer weather will be short-lived however, as a significant
trough digs across the central/eastern CONUS early next week,
sending an Arctic cold front through central Illinois. Models
continue to suggest a band of post-frontal precip on Sunday. Given
the strength of the boundary and the approaching upper wave, will
mention a chance for snow as the front passes. Little or no
accumulation is expected, as system will have only limited
moisture to work with and will be moving rather fast. Once front
clears the area, sharply colder conditions are expected on Monday.
850mb temps drop to between -12 and -14C, resulting in highs temps
plunging into the teens.
Clipper system for early next week still remains in question, with
the 00z Dec 26 models exhibiting a 24-hour timing discrepancy.
ECMWF shows system skirting through central Illinois Monday/Monday
night, while the GFS delays it until Tuesday/Tuesday night. This
is a marked change for the ECMWF and given the fact that the GEM
more closely resembles the GFS solution, will stick with the GFS
in the extended. As a result, will continue with cold/dry weather
on Monday, then will bring snow chances into the area Tuesday and
Tuesday night. At this point, it appears greatest chance for
accumulating snow will mainly be confined to the northern half of
the CWA, but this will likely be fine-tuned as models gradually get
a better handle on the wave.
Barnes
&&
.ILX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS GOODLAND KS
145 PM MST THU DEC 26 2013
.SHORT TERM...(THIS EVENING THROUGH FRIDAY)
ISSUED AT 1258 PM MST THU DEC 26 2013
A WEAK UPPER LEVEL SHORTWAVE TROUGH DROPPING SOUTH/SOUTHEAST ACROSS
THE HIGH PLAINS BROUGHT SOME CLOUD COVER TO THE REGION THIS MORNING.
LIMITED MID-LEVEL MOISTURE ASSOCIATED WITH THIS DISTURBANCE AND
UNFAVORABLE DYNAMICS MEANS NO PRECIPITATION WITH THIS EVENT.
TOMORROW WILL LIKELY BE THE WARMEST DAY OF THE WEEK FOR MOST
LOCATIONS THANKS TO LOW/MID-LEVEL WARM AIR ADVECTION AND SUNNY SKIES.
HAPPY TO SEE THE NCEP SNOW DEPTH ASSIMILATION DID A PRETTY GOOD JOB
WITH ITS 06Z DAILY UPDATE...REMOVING ALL BUT A SMALL PATCH OF SNOW
COVER IN NORTHEAST RED WILLOW AND WESTERN FURNAS COUNTIES IN NEBRASKA.
SO HAVE MORE CONFIDENCE IN 06Z/12Z CYCLE GUIDANCE IN SW NEBRASKA THAN
EARLIER CYCLES WHICH HAD A WIDE SWATH OF SNOW COVER ACROSS ALL OF SW
NEB AND NORTHEAST COLORADO...WHICH INFLUENCED LOW-LEVEL MODEL TEMP
AND MOISTURE FIELDS /QUITE DRAMATICALLY IN THE CASE OF THE NAM/.
TODAY...THURSDAY...MOSTLY SUNNY AND MILD WITH A LIGHT BREEZE.
DISTURBANCE MOVING SOUTH/SOUTHEAST ACROSS THE HIGH PLAINS THE CAUSE
FOR THE MID/HIGH-LEVEL CLOUDS TODAY. CLOUDS ARE THINNING OUT FROM
EARLIER THIS MORNING WHEN THE WERE OVER WESTERN NEBRASKA AND EASTERN
WYOMING...AND WHILE THE RAP IS A LITTLE AGGRESSIVE ABOUT DEVELOPING
THICKER MID-LEVEL CLOUDS THIS AFTERNOON ALONG I70 BELIEVE THE CLOUD
COVER WILL HAVE MINIMAL IMPACT ON HIGH TEMPS TODAY. WITH THE SURFACE
TROUGH OVER EASTERN COLORADO AND UPPER LEVEL DISTURBANCE MOVING THROUGH
EXPECT ANOTHER DAY OF BREEZY WINDS...DECREASING LATE IN THE
AFTERNOON. PREVIOUS FORECAST HIGHS WERE NUDGED UP JUST A TAD TO
ACCOUNT FOR LESS CLOUD COVER BASED ON HOURLY TEMP TREND THUS FAR.
TONIGHT...A FEW HIGH CLOUDS AND NEAR NORMAL TEMPS. SIMILAR TO LAST
NIGHT LIGHT WINDS ARE EXPECTED TO CONTINUE THROUGH THE NIGHT...AND
GIVEN THE DIRECTION /WESTERLY/ AND THE LOW/MID-LEVEL WARM AIR
ADVECTION THINK MANY SPOTS WILL NOT DIP BELOW THE LOW 20S. /EXCEPT
FOR THE USUAL COLD SPOTS SUCH AS WESTERN CHEYENNE COUNTY COLORADO./
TOMORROW...FRIDAY...SUNNY AND WARM. THE WEAK SURFACE TROUGH ACROSS
EASTERN COLORADO REMAINS IN PLACE AS A BROAD H5 LONGWAVE RIDGE
APPROACHES FROM THE WEST. WINDS WILL BE LIGHT OUT OF THE
WEST/SOUTHWEST...ONLY AIDING IN THE WARMTH. HIGHS WILL BE IN THE LOW
TO MID 60S BASED ON CURRENT GUIDANCE. THE RECORD HIGH AT BURLINGTON
COLORADO MAY BE IN JEOPARDY...WHICH CURRENTLY STANDS AT 65 SET IN
1976. /ELSEWHERE RECORDS ARE WELL ABOVE FORECAST HIGHS./
.LONG TERM...(FRIDAY NIGHT THROUGH THURSDAY)
ISSUED AT 145 PM MST THU DEC 26 2013
FRIDAY NIGHT-SUNDAY...CONTINUED WARM AND DRY SATURDAY AHEAD OF AN
UPPER TROUGH THAT MOVES THROUGH SATURDAY NIGHT. ON SUNDAY FORECAST
AREA UNDER NORTHWEST FLOW ALOFT. AHEAD OF THE UPPER TROUGH STRONG
NORTH/NORTHWEST WINDS MOVE IN EARLY SATURDAY AFTERNOON WITH
SUSTAINED SPEEDS AROUND 20-30 MPH WITH HIGHER GUSTS. SOME GUSTY
WINDS CONTINUE THROUGH EARLY SATURDAY NIGHT BEFORE SLOWLY DECREASING
AFTER MIDNIGHT AND THROUGH THE DAY SUNDAY. CANT COMPLETELY RULE OUT
SOME VERY LIGHT PRECIPITATION CHANCES EARLY SATURDAY NIGHT AS BETTER
MOISTURE BUT LIMITED DYNAMICS WITH THE UPPER TROUGH MOVE THROUGH.
AFTER MIDNIGHT MOISTURE QUICKLY MOVES AWAY FROM THE AREA WITH NEAR
ZERO CHANCE ON SUNDAY.
LOWS TONIGHT UPPER TEENS TO MID 20S WITH HIGHS SATURDAY MID 50S TO
LOW 60S. LOWS SATURDAY NIGHT IN THE TEENS WITH MID 20S (EAST) TO
LOW/MID 30S FAR WEST SUNDAY.
SUNDAY NIGHT-THURSDAY...FORECAST AREA REMAINS UNDER NORTHWEST FLOW
ALOFT THROUGH THE PERIOD. WEATHER SYSTEMS MOVE THROUGH THE FLOW
SUNDAY NIGHT THEN AGAIN MONDAY NIGHT AND TUESDAY NIGHT.
HOWEVER...DOESNT LOOK LIKE ANY OF THESE PRODUCE ANY PRECIPITATION.
TEMPERATURES SLOWLY WARM MONDAY AND TUESDAY BEFORE COOLING DOWN
WEDNESDAY AND THEN WARMING UP AGAIN THURSDAY.
LOWS SUNDAY NIGHT IN THE TEENS WITH LOW TO MID 20S MONDAY
NIGHT-WEDNESDAY NIGHT. HIGHS MONDAY LOW TO MID 40S ALTHOUGH
GFS/ECMWF 850 TEMPS SUPPORT READINGS A BIT HIGHER. FOR TUESDAY LOW
TO MID 40S EAST WITH UPPER 40S TO LOW 50S WEST. ON WEDNESDAY AN
UNCERTAIN LOW TO MID 40S AS DIFFERENCES SHOW UP IN JUST HOW MUCH
COOLER IT WILL BE WITH LARGE DISPARITY BETWEEN ECMWF/GFS 850
TEMPERATURES. FOR THURSDAY GENERALLY MID TO UPPER 40S...ECMWF
SUGGESTS IT WILL BE WARMER THEN CURRENT FORECAST PER 850
TEMPERATURES WHILE GFS ABOUT 5C COOLER.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z FRIDAY AFTERNOON)
ISSUED AT 1030 AM MST THU DEC 26 2013
VFR CONDITIONS WILL PERSIST THROUGH THE TAF PERIOD AT GLD AND MCK. A
FEW MID/HIGH CLOUDS POSSIBLE THIS AFTERNOON AT GLD AS AN UPPER LEVEL
DISTURBANCE MOVES ACROSS THE REGION. BREEZY AT TIMES THIS AFTERNOON
SIMILAR TO YESTERDAY WITH WINDS 12 TO 18 KTS OUT OF THE NORTHWEST
WITH A FEW GUSTS UP TO 25 KTS POSSIBLE. OVERNIGHT WINDS WILL BACK
TO THE WEST WITH A LIGHT WIND CONTINUING THROUGH THE NIGHT AS HAS
BEEN THE PATTERN THE PAST FEW NIGHTS...THOUGH NOT AS INTENSE.
&&
.GLD WATCHES/WARNINGS/ADVISORIES...
KS...NONE.
CO...NONE.
NE...NONE.
&&
$$
SHORT TERM...JJM
LONG TERM...99
AVIATION...JJM
AREA FORECAST DISCUSSION
NWS GOODLAND KS
1258 PM MST THU DEC 26 2013
.SHORT TERM...(THIS EVENING THROUGH FRIDAY)
ISSUED AT 1258 PM MST THU DEC 26 2013
A WEAK UPPER LEVEL SHORTWAVE TROUGH DROPPING SOUTH/SOUTHEAST ACROSS
THE HIGH PLAINS BROUGHT SOME CLOUD COVER TO THE REGION THIS MORNING.
LIMITED MID-LEVEL MOISTURE ASSOCIATED WITH THIS DISTURBANCE AND
UNFAVORABLE DYNAMICS MEANS NO PRECIPITATION WITH THIS EVENT.
TOMORROW WILL LIKELY BE THE WARMEST DAY OF THE WEEK FOR MOST
LOCATIONS THANKS TO LOW/MID-LEVEL WARM AIR ADVECTION AND SUNNY SKIES.
HAPPY TO SEE THE NCEP SNOW DEPTH ASSIMILATION DID A PRETTY GOOD JOB
WITH ITS 06Z DAILY UPDATE...REMOVING ALL BUT A SMALL PATCH OF SNOW
COVER IN NORTHEAST RED WILLOW AND WESTERN FURNAS COUNTIES IN NEBRASKA.
SO HAVE MORE CONFIDENCE IN 06Z/12Z CYCLE GUIDANCE IN SW NEBRASKA THAN
EARLIER CYCLES WHICH HAD A WIDE SWATH OF SNOW COVER ACROSS ALL OF SW
NEB AND NORTHEAST COLORADO...WHICH INFLUENCED LOW-LEVEL MODEL TEMP
AND MOISTURE FIELDS /QUITE DRAMATICALLY IN THE CASE OF THE NAM/.
TODAY...THURSDAY...MOSTLY SUNNY AND MILD WITH A LIGHT BREEZE.
DISTURBANCE MOVING SOUTH/SOUTHEAST ACROSS THE HIGH PLAINS THE CAUSE
FOR THE MID/HIGH-LEVEL CLOUDS TODAY. CLOUDS ARE THINNING OUT FROM
EARLIER THIS MORNING WHEN THE WERE OVER WESTERN NEBRASKA AND EASTERN
WYOMING...AND WHILE THE RAP IS A LITTLE AGGRESSIVE ABOUT DEVELOPING
THICKER MID-LEVEL CLOUDS THIS AFTERNOON ALONG I70 BELIEVE THE CLOUD
COVER WILL HAVE MINIMAL IMPACT ON HIGH TEMPS TODAY. WITH THE SURFACE
TROUGH OVER EASTERN COLORADO AND UPPER LEVEL DISTURBANCE MOVING THROUGH
EXPECT ANOTHER DAY OF BREEZY WINDS...DECREASING LATE IN THE
AFTERNOON. PREVIOUS FORECAST HIGHS WERE NUDGED UP JUST A TAD TO
ACCOUNT FOR LESS CLOUD COVER BASED ON HOURLY TEMP TREND THUS FAR.
TONIGHT...A FEW HIGH CLOUDS AND NEAR NORMAL TEMPS. SIMILAR TO LAST
NIGHT LIGHT WINDS ARE EXPECTED TO CONTINUE THROUGH THE NIGHT...AND
GIVEN THE DIRECTION /WESTERLY/ AND THE LOW/MID-LEVEL WARM AIR
ADVECTION THINK MANY SPOTS WILL NOT DIP BELOW THE LOW 20S. /EXCEPT
FOR THE USUAL COLD SPOTS SUCH AS WESTERN CHEYENNE COUNTY COLORADO./
TOMORROW...FRIDAY...SUNNY AND WARM. THE WEAK SURFACE TROUGH ACROSS
EASTERN COLORADO REMAINS IN PLACE AS A BROAD H5 LONGWAVE RIDGE
APPROACHES FROM THE WEST. WINDS WILL BE LIGHT OUT OF THE
WEST/SOUTHWEST...ONLY AIDING IN THE WARMTH. HIGHS WILL BE IN THE LOW
TO MID 60S BASED ON CURRENT GUIDANCE. THE RECORD HIGH AT BURLINGTON
COLORADO MAY BE IN JEOPARDY...WHICH CURRENTLY STANDS AT 65 SET IN
1976. /ELSEWHERE RECORDS ARE WELL ABOVE FORECAST HIGHS./
.LONG TERM...(SUNDAY THROUGH WEDNESDAY)
ISSUED AT 318 AM MST THU DEC 26 2013
SUNDAY THROUGH WEDNESDAY...NOT MUCH CHANGE WITH THE LARGE SCALE
PATTERN. A SHORTWAVE TROUGH WILL MOVE THROUGH THE CWA ON SUNDAY AND
COLD AIR WILL FILTER INTO THE CWA WITH A SURFACE HIGH. AS THE
SURFACE HIGH MOVES IN BEHIND THE LEE TROUGH TO THE SOUTH...NORTH
WINDS MAY REMAIN FAIRLY BREEZY ON SUNDAY MORNING. INCREASED WINDS
SLIGHTLY IN THE EASTERN PORTION OF THE CWA AT THE 12Z AND 18Z TIME
FRAMES. CLOUD COVER SHOULD BEGIN TO DECREASE ON SUNDAY MID-DAY INTO
THE AFTERNOON.
A LARGE UPPER TROUGH WILL BE OVER THE EASTERN U.S. AND MIDWEST AND
AN UPPER RIDGE WILL RESIDE OVER THE WESTERN U.S. WITH THE CWA UNDER
NORTHWEST FLOW ALOFT...BEING IN-BETWEEN LARGE SCALE FEATURES SUNDAY
THROUGH WEDNESDAY. ANOTHER MID-UPPER SHORTWAVE TROUGH WILL MOVE
THROUGH THE CWA ON TUESDAY NIGHT INTO WEDNESDAY. A WEAK COLD FRONT
WILL PASS THROUGH AHEAD OF THE SHORTWAVE TROUGH DURING THIS
TIME...DROPPING TEMPERATURES SLIGHTLY IF MUCH AT ALL. PRECIPITATION IS
NOT REALLY EXPECTED WITH THIS WAVE AS SOUNDINGS SHOW THE MID-LEVELS
SATURATED BUT DRIER TOWARDS THE SURFACE. AN INCREASE IN MID-LEVEL
CLOUD COVER CAN BE EXPECTED...BUT THE FORECAST WAS KEPT DRY AT THE
MOMENT.
TEMPERATURES IN THE EXTENDED WILL BE BELOW NORMAL TO START ON SUNDAY
...WITH HIGHS IN THE UPPER 20S TO MID 30S AND LOWS IN THE TEENS
SUNDAY NIGHT...AND WILL BE NEAR TO ABOVE NORMAL THROUGHOUT THE
REMAINDER OF THE EXTENDED. HIGHS MONDAY THROUGH TUESDAY WILL
STEADILY INCREASE FROM THE LOW TO MID 40S ON MONDAY INTO THE UPPER
40S TO LOW 50S ON TUESDAY. THE WEAK FRONT MOVING THROUGH ON TUESDAY NIGHT
WILL ONLY SLIGHTLY AFFECT HIGHS ON WEDNESDAY...REACHING THE MID TO
UPPER 40S WITH SOME LOCATIONS NEAR 50. THE COLD FRONT MAY TRACK
FURTHER EAST...WHICH COULD HAVE EVEN LESS OF AN EFFECT ON HIGH
TEMPERATURES FOR DAY 7.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z FRIDAY AFTERNOON)
ISSUED AT 1030 AM MST THU DEC 26 2013
VFR CONDITIONS WILL PERSIST THROUGH THE TAF PERIOD AT GLD AND MCK. A
FEW MID/HIGH CLOUDS POSSIBLE THIS AFTERNOON AT GLD AS AN UPPER LEVEL
DISTURBANCE MOVES ACROSS THE REGION. BREEZY AT TIMES THIS AFTERNOON
SIMILAR TO YESTERDAY WITH WINDS 12 TO 18 KTS OUT OF THE NORTHWEST
WITH A FEW GUSTS UP TO 25 KTS POSSIBLE. OVERNIGHT WINDS WILL BACK
TO THE WEST WITH A LIGHT WIND CONTINUING THROUGH THE NIGHT AS HAS
BEEN THE PATTERN THE PAST FEW NIGHTS...THOUGH NOT AS INTENSE.
&&
.GLD WATCHES/WARNINGS/ADVISORIES...
KS...NONE.
CO...NONE.
NE...NONE.
&&
$$
SHORT TERM...JJM
LONG TERM...ALW
AVIATION...JJM
AREA FORECAST DISCUSSION
NWS JACKSON KY
105 PM EST THU DEC 26 2013
.UPDATE...
ISSUED AT 105 PM EST THU DEC 26 2013
CLOUDS HAVE QUICKLY SCOURED OUT ACROSS THE AREA WITH SUNSHINE
EXPECTED THROUGH THE REST OF THE AFTERNOON. NO CHANGES NEEDED AT THIS
TIME.
UPDATE ISSUED AT 940 AM EST THU DEC 26 2013
A BAND OF SHALLOW LOW CLOUDS CONTINUES TO PUSH SOUTHEAST THIS MORNING
ACROSS EASTERN KENTUCKY. HOWEVER...THESE CLOUDS ARE ALREADY
DEVELOPING HOLES AND STARTING TO ERODE. THIS TREND SHOULD CONTINUE AS
WE HEAD TOWARDS SUNNY SKIES THIS AFTERNOON. WILL INCREASE SKY COVER
OVER THE NEXT FEW HOURS FOR THE SOUTHEAST...BEFORE GOING MAINLY SUNNY
BY THIS AFTERNOON. HAVE ALSO LOWERED RELATIVE HUMIDITY SLIGHTLY GIVEN
THE DECENT MIXING POTENTIAL UNDER THE SUNNY SKIES THIS AFTERNOON.
UPDATED FORECAST IS ALREADY OUT.
UPDATE ISSUED AT 715 AM EST THU DEC 26 2013
UPDATED THE GRIDS TO FINE TUNE TEMPERATURES...MAINLY MILDER...FOR THE
NEXT SEVERAL HOURS PER LATEST OBS AND TRENDS. DID ALSO ADJUST SKY
COVER TO BRING THE POST FRONTAL SC FURTHER SOUTH AND EAST FOR THE
FIRST PART OF THE MORNING...BUT STILL EXPECT THESE TO BE MOSTLY GONE
BY NOON. THE GRIDS HAVE BEEN SENT TO THE NDFD AND WEB SERVERS.
&&
.SHORT TERM...(TODAY THROUGH FRIDAY)
ISSUED AT 335 AM EST THU DEC 26 2013
07Z SFC ANALYSIS SHOWS A MOSTLY DRY COLD FRONT CROSSING EAST
KENTUCKY. THIS IS ACCOMPANIED BY A LOWER DECK OF CLOUDS AND SOME
RETURNS ON RADAR...MOSTLY VIRGA. LOWER CLOUDS...NEAR MVFR...TRAIL
THIS BOUNDARY AND WILL MOVE OVER THE NORTHERN TWO THIRDS OF THE CWA
INTO THE FIRST PART OF THE MORNING. THIS SHOULD KEEP TEMPERATURES
FROM FALLING MUCH FURTHER THROUGH THE AREA INTO DAWN. CURRENTLY THEY
VARY FROM THE UPPER 20S IN SOME VALLEYS TO THE MID 30S ON THE
RIDGES...WHILE DEWPOINTS ARE GENERALLY IN THE LOW AND MID 20S.
THE MODELS ARE IN GOOD ENOUGH AGREEMENT ALOFT THROUGH THE SHORT TERM
AS THEY ALL TAKE A SHARP SHORTWAVE NORTHEAST AND AWAY FROM THE OHIO
VALLEY TODAY. LATER...ANOTHER RIPPLE MOVES THROUGH THE BASE OF THE
RETREATING LARGE EAST CANADIAN TROUGH...PASSING HARMLESSLY THROUGH
THE AREA MIDDAY FRIDAY. HEIGHTS WILL THEN RISE OVER THE STATE AHEAD
OF A BROAD AND UNCONSOLIDATED AREA OF LOWER ONES ASSOCIATED WITH THE
POOLING ENERGY OVER SOUTH CENTRAL TEXAS. THE MODELS ARE HAVING THE
MOST DIFFICULTIES WITH THIS FEATURE AS THE NAM IS OUT OF STEP WITH
THE OTHERS IN KEEPING THE RESULTANT MID LEVEL LOW WEAKER AND A NOTCH
FURTHER EAST THAN CONSENSUS. THESE DIFFERENCES WILL AFFECT THE
FORECAST OVER THE WEEKEND...BEYOND THE SHORT TERM SO THE NAM12 WAS
PRIMARILY USED...ALONG WITH THE LATEST HRRR FOR THE NEAR TERM WX...
TO GUIDE THIS PART OF THE FORECAST.
SENSIBLE WEATHER WILL FEATURE A FLEETING CHANCE OF MAINLY FLURRIES
PASSING THROUGH FAR EAST KENTUCKY OVER THE NEXT COUPLE OF HOURS.
OTHERWISE...IT WILL BE A DRY AND QUIET FORECAST TO END THE WORK WEEK
AS SFC HIGH PRESSURE IS BUFFETED BY PASSING MID LEVEL WAVES AND
THEIR SFC REFLECTIONS TO THE NORTH OF THE AREA. THIS WILL BE NOTED
MAINLY IN TIMES OF MID AND HIGH CLOUDS BRUSHING PAST THE CWA.
TEMPERATURES THROUGH EAST KENTUCKY WILL BE SEASONABLY NEAR NORMAL
WHILE WE AWAIT THE SOUTHERN DEVELOPMENT FOR A SHOT AT A RETURN OF
PCPN LATER IN THE WEEKEND.
FOLLOWED THE CONSSHORT AND ITS BC PARTNER FOR T...TD...AND WINDS
THROUGH 12Z FRIDAY WITH SOME BLENDING IN WITH THE DIURNAL FROM THE
NAM12 FOR HOURLY TEMPS. OTHERWISE...THE CONSALL WAS USED AS A
STARTING POINT. DID ADD IN SOME MINOR RIDGE AND VALLEY TEMPERATURE
DIFFERENCES TONIGHT WHILE KEEPING POPS IN THE LOW SINGLE DIGITS AT
BEST...IN LINE WITH MOS...OUTSIDE OF THE NEXT FEW HOURS IN THE FAR
EAST.
.LONG TERM...(FRIDAY NIGHT THROUGH WEDNESDAY)
ISSUED AT 330 AM EST THU DEC 26 2013
THE BEGINNING OF THE EXTENDED PERIOD /12Z SATURDAY/ WILL HOST ZONAL
FLOW ALOFT AND SURFACE HIGH PRESSURE...MAKING FOR CLEAR SKIES IN THE
MORNING. HOWEVER...THIS SET UP WILL BE SHORT LIVED...AS TWO SYSTEMS
WILL BEGIN TO INTERACT ON EASTERN KY OVER THE NEXT 24 TO 36 HOURS.
THE FIRST OF THESE SYSTEMS...A STRONG UPPER LEVEL SHORTWAVE ACROSS
THE SOUTHERN PLAINS MOVING SLOWLY NEWARD. A SURFACE LOW PRESSURE
SYSTEM WILL DEVELOP SLIGHTLY EASTWARD OF THE UPPER TROUGH...PULLING
IN MOISTURE OFF THE GULF OF MEXICO ACROSS THE SOUTHERN STATES AND
THEN INTO SOUTHERN AND EASTERN KY SATURDAY NIGHT/SUNDAY MORNING. THE
SECOND SHORTWAVE WILL BE SLIGHTLY WEAKER...MOVING IN JUST BEHIND AND
NORTH OF THE ORIGINAL WAVE. THIS WILL PUSH A COLD FRONT ACROSS
KY FROM THE NW MONDAY EVENING/NIGHT. OF THE TWO...EXPECT THE BEST
PRECIP CHANCES AND QPF TO COME FROM THE FIRST SYSTEM...BEGINNING
RIGHT BEFORE 6Z SUNDAY AND CONTINUING THROUGH SUNDAY
AFTERNOON/EVENING. THEN THE SECOND WAVE OF MOISTURE BEGINS TO HIT KY
FROM THE NORTH AND WEST SUNDAY NIGHT INTO MONDAY. THIS TIME THE
PRECIP WILL BE LIGHTER AND SCATTERED IN NATURE.
UNFORTUNATELY...MODELS ARE STILL NOT COMPLETELY AGREEING ON THEIR
TIMING AND SET UP...SO WILL CONTINUE WITH THE ALLBLEND OUTPUT AT
THIS TIME FOR POPS.
WITH A WARM PULL FROM THE SOUTH AHEAD OF THESE TWO SYSTEMS...TEMPS
WILL RISE TO ABOVE NORMALS SATURDAY AND SUNDAY /UPPER 40S AND LOW
50S/. HOWEVER...ONCE THE COLD FRONT ACCOMPANYING THE SECOND SYSTEM
PUSHES THROUGH...IT WILL USHER IN COLDER AIR FROM THE NW.
TEMPERATURE DIFFERENCES COULD BE AS MUCH AS 15 DEGREES COOLER FROM
SUNDAY INTO MONDAY...FALLING NEAR FREEZING FOR HIGHS. THIS
TEMPERATURE DROP WILL BE WHAT GOVERNS RAIN VS. SNOW WITH THIS SECOND
SYSTEM. AT PRESENT...HAVE ALL RAIN IN FORECAST UNTIL AROUND
MIDNIGHT...AT WHICH POINT A RAIN AND SNOW MIX WILL BE
POSSIBLE...BEFORE TEMPS DROP ENOUGH TO GOVERN ALL SNOW BY 9Z.
PROLONGED TIME PERIOD FOR WHICH ACCUMULATIONS COULD OCCUR COMPARED
TO PREVIOUS FORECAST...BUT DID DROP AMOUNTS SLIGHTLY IN THE WESTERN
HALF OF THE CWA. ANYWHERE BETWEEN A DUSTING TO A COUPLE TENTHS OF AN
INCH WILL BE POSSIBLE ACROSS MUCH THE CWA...WITH THE HIGHER TERRAIN
EXPECTED TO SEE A BIT MORE...BETWEEN A HALF AN INCH TO ONE INCH.
OBVIOUSLY THIS SYSTEM IS FAIRLY FAR OUT IN THE FORECAST...SO EXPECT
THESE TOTALS TO CONTINUE TO CHANGE AS WE GET CLOSER TO THE ONSET.
WITH A TROUGHING PATTERN SETTING UP ACROSS THE EASTERN U.S...COULD
SEE SEVERAL MORE SHORTWAVES MOVE THROUGH THE TROUGH OVER THE FEW
DAYS FOLLOWING. AT THIS TIME...MODEL SOLUTIONS ARE KEEPING ANY
MOISTURE RELATED TO THESE SHORTWAVES AWAY FROM EASTERN KY. THAT
BEING SAID...TUESDAY NIGHT/WEDNESDAY MORNING WILL BE A TIME FRAME TO
WATCH...AS ANY VARIATIONS SOUTHWARD FROM WHERE THE BLENDED RUN
PLACES THE SYSTEM...KJKL COULD SEE PRECIPITATION.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z FRIDAY AFTERNOON)
ISSUED AT 105 PM EST THU DEC 26 2013
VFR CONDITIONS WILL REMAIN ACROSS EASTERN KENTUCKY OVER THE NEXT 24
TO 36 HOURS WITH LIGHT WINDS.
&&
.JKL WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...KAS
SHORT TERM...GREIF
LONG TERM...JMW
AVIATION...KAS
AREA FORECAST DISCUSSION
NWS JACKSON KY
940 AM EST THU DEC 26 2013
.UPDATE...
ISSUED AT 940 AM EST THU DEC 26 2013
A BAND OF SHALLOW LOW CLOUDS CONTINUES TO PUSH SOUTHEAST THIS MORNING
ACROSS EASTERN KENTUCKY. HOWEVER...THESE CLOUDS ARE ALREADY
DEVELOPING HOLES AND STARTING TO ERODE. THIS TREND SHOULD CONTINUE AS
WE HEAD TOWARDS SUNNY SKIES THIS AFTERNOON. WILL INCREASE SKY COVER
OVER THE NEXT FEW HOURS FOR THE SOUTHEAST...BEFORE GOING MAINLY SUNNY
BY THIS AFTERNOON. HAVE ALSO LOWERED RELATIVE HUMIDITY SLIGHTLY GIVEN
THE DECENT MIXING POTENTIAL UNDER THE SUNNY SKIES THIS AFTERNOON.
UPDATED FORECAST IS ALREADY OUT.
UPDATE ISSUED AT 715 AM EST THU DEC 26 2013
UPDATED THE GRIDS TO FINE TUNE TEMPERATURES...MAINLY MILDER...FOR THE
NEXT SEVERAL HOURS PER LATEST OBS AND TRENDS. DID ALSO ADJUST SKY
COVER TO BRING THE POST FRONTAL SC FURTHER SOUTH AND EAST FOR THE
FIRST PART OF THE MORNING...BUT STILL EXPECT THESE TO BE MOSTLY GONE
BY NOON. THE GRIDS HAVE BEEN SENT TO THE NDFD AND WEB SERVERS.
&&
.SHORT TERM...(TODAY THROUGH FRIDAY)
ISSUED AT 335 AM EST THU DEC 26 2013
07Z SFC ANALYSIS SHOWS A MOSTLY DRY COLD FRONT CROSSING EAST
KENTUCKY. THIS IS ACCOMPANIED BY A LOWER DECK OF CLOUDS AND SOME
RETURNS ON RADAR...MOSTLY VIRGA. LOWER CLOUDS...NEAR MVFR...TRAIL
THIS BOUNDARY AND WILL MOVE OVER THE NORTHERN TWO THIRDS OF THE CWA
INTO THE FIRST PART OF THE MORNING. THIS SHOULD KEEP TEMPERATURES
FROM FALLING MUCH FURTHER THROUGH THE AREA INTO DAWN. CURRENTLY THEY
VARY FROM THE UPPER 20S IN SOME VALLEYS TO THE MID 30S ON THE
RIDGES...WHILE DEWPOINTS ARE GENERALLY IN THE LOW AND MID 20S.
THE MODELS ARE IN GOOD ENOUGH AGREEMENT ALOFT THROUGH THE SHORT TERM
AS THEY ALL TAKE A SHARP SHORTWAVE NORTHEAST AND AWAY FROM THE OHIO
VALLEY TODAY. LATER...ANOTHER RIPPLE MOVES THROUGH THE BASE OF THE
RETREATING LARGE EAST CANADIAN TROUGH...PASSING HARMLESSLY THROUGH
THE AREA MIDDAY FRIDAY. HEIGHTS WILL THEN RISE OVER THE STATE AHEAD
OF A BROAD AND UNCONSOLIDATED AREA OF LOWER ONES ASSOCIATED WITH THE
POOLING ENERGY OVER SOUTH CENTRAL TEXAS. THE MODELS ARE HAVING THE
MOST DIFFICULTIES WITH THIS FEATURE AS THE NAM IS OUT OF STEP WITH
THE OTHERS IN KEEPING THE RESULTANT MID LEVEL LOW WEAKER AND A NOTCH
FURTHER EAST THAN CONSENSUS. THESE DIFFERENCES WILL AFFECT THE
FORECAST OVER THE WEEKEND...BEYOND THE SHORT TERM SO THE NAM12 WAS
PRIMARILY USED...ALONG WITH THE LATEST HRRR FOR THE NEAR TERM WX...
TO GUIDE THIS PART OF THE FORECAST.
SENSIBLE WEATHER WILL FEATURE A FLEETING CHANCE OF MAINLY FLURRIES
PASSING THROUGH FAR EAST KENTUCKY OVER THE NEXT COUPLE OF HOURS.
OTHERWISE...IT WILL BE A DRY AND QUIET FORECAST TO END THE WORK WEEK
AS SFC HIGH PRESSURE IS BUFFETED BY PASSING MID LEVEL WAVES AND
THEIR SFC REFLECTIONS TO THE NORTH OF THE AREA. THIS WILL BE NOTED
MAINLY IN TIMES OF MID AND HIGH CLOUDS BRUSHING PAST THE CWA.
TEMPERATURES THROUGH EAST KENTUCKY WILL BE SEASONABLY NEAR NORMAL
WHILE WE AWAIT THE SOUTHERN DEVELOPMENT FOR A SHOT AT A RETURN OF
PCPN LATER IN THE WEEKEND.
FOLLOWED THE CONSSHORT AND ITS BC PARTNER FOR T...TD...AND WINDS
THROUGH 12Z FRIDAY WITH SOME BLENDING IN WITH THE DIURNAL FROM THE
NAM12 FOR HOURLY TEMPS. OTHERWISE...THE CONSALL WAS USED AS A
STARTING POINT. DID ADD IN SOME MINOR RIDGE AND VALLEY TEMPERATURE
DIFFERENCES TONIGHT WHILE KEEPING POPS IN THE LOW SINGLE DIGITS AT
BEST...IN LINE WITH MOS...OUTSIDE OF THE NEXT FEW HOURS IN THE FAR
EAST.
.LONG TERM...(FRIDAY NIGHT THROUGH WEDNESDAY)
ISSUED AT 330 AM EST THU DEC 26 2013
THE BEGINNING OF THE EXTENDED PERIOD /12Z SATURDAY/ WILL HOST ZONAL
FLOW ALOFT AND SURFACE HIGH PRESSURE...MAKING FOR CLEAR SKIES IN THE
MORNING. HOWEVER...THIS SET UP WILL BE SHORT LIVED...AS TWO SYSTEMS
WILL BEGIN TO INTERACT ON EASTERN KY OVER THE NEXT 24 TO 36 HOURS.
THE FIRST OF THESE SYSTEMS...A STRONG UPPER LEVEL SHORTWAVE ACROSS
THE SOUTHERN PLAINS MOVING SLOWLY NEWARD. A SURFACE LOW PRESSURE
SYSTEM WILL DEVELOP SLIGHTLY EASTWARD OF THE UPPER TROUGH...PULLING
IN MOISTURE OFF THE GULF OF MEXICO ACROSS THE SOUTHERN STATES AND
THEN INTO SOUTHERN AND EASTERN KY SATURDAY NIGHT/SUNDAY MORNING. THE
SECOND SHORTWAVE WILL BE SLIGHTLY WEAKER...MOVING IN JUST BEHIND AND
NORTH OF THE ORIGINAL WAVE. THIS WILL PUSH A COLD FRONT ACROSS
KY FROM THE NW MONDAY EVENING/NIGHT. OF THE TWO...EXPECT THE BEST
PRECIP CHANCES AND QPF TO COME FROM THE FIRST SYSTEM...BEGINNING
RIGHT BEFORE 6Z SUNDAY AND CONTINUING THROUGH SUNDAY
AFTERNOON/EVENING. THEN THE SECOND WAVE OF MOISTURE BEGINS TO HIT KY
FROM THE NORTH AND WEST SUNDAY NIGHT INTO MONDAY. THIS TIME THE
PRECIP WILL BE LIGHTER AND SCATTERED IN NATURE.
UNFORTUNATELY...MODELS ARE STILL NOT COMPLETELY AGREEING ON THEIR
TIMING AND SET UP...SO WILL CONTINUE WITH THE ALLBLEND OUTPUT AT
THIS TIME FOR POPS.
WITH A WARM PULL FROM THE SOUTH AHEAD OF THESE TWO SYSTEMS...TEMPS
WILL RISE TO ABOVE NORMALS SATURDAY AND SUNDAY /UPPER 40S AND LOW
50S/. HOWEVER...ONCE THE COLD FRONT ACCOMPANYING THE SECOND SYSTEM
PUSHES THROUGH...IT WILL USHER IN COLDER AIR FROM THE NW.
TEMPERATURE DIFFERENCES COULD BE AS MUCH AS 15 DEGREES COOLER FROM
SUNDAY INTO MONDAY...FALLING NEAR FREEZING FOR HIGHS. THIS
TEMPERATURE DROP WILL BE WHAT GOVERNS RAIN VS. SNOW WITH THIS SECOND
SYSTEM. AT PRESENT...HAVE ALL RAIN IN FORECAST UNTIL AROUND
MIDNIGHT...AT WHICH POINT A RAIN AND SNOW MIX WILL BE
POSSIBLE...BEFORE TEMPS DROP ENOUGH TO GOVERN ALL SNOW BY 9Z.
PROLONGED TIME PERIOD FOR WHICH ACCUMULATIONS COULD OCCUR COMPARED
TO PREVIOUS FORECAST...BUT DID DROP AMOUNTS SLIGHTLY IN THE WESTERN
HALF OF THE CWA. ANYWHERE BETWEEN A DUSTING TO A COUPLE TENTHS OF AN
INCH WILL BE POSSIBLE ACROSS MUCH THE CWA...WITH THE HIGHER TERRAIN
EXPECTED TO SEE A BIT MORE...BETWEEN A HALF AN INCH TO ONE INCH.
OBVIOUSLY THIS SYSTEM IS FAIRLY FAR OUT IN THE FORECAST...SO EXPECT
THESE TOTALS TO CONTINUE TO CHANGE AS WE GET CLOSER TO THE ONSET.
WITH A TROUGHING PATTERN SETTING UP ACROSS THE EASTERN U.S...COULD
SEE SEVERAL MORE SHORTWAVES MOVE THROUGH THE TROUGH OVER THE FEW
DAYS FOLLOWING. AT THIS TIME...MODEL SOLUTIONS ARE KEEPING ANY
MOISTURE RELATED TO THESE SHORTWAVES AWAY FROM EASTERN KY. THAT
BEING SAID...TUESDAY NIGHT/WEDNESDAY MORNING WILL BE A TIME FRAME TO
WATCH...AS ANY VARIATIONS SOUTHWARD FROM WHERE THE BLENDED RUN
PLACES THE SYSTEM...KJKL COULD SEE PRECIPITATION.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z FRIDAY MORNING)
ISSUED AT 655 AM EST THU DEC 26 2013
MAINLY VFR CONDITIONS WILL PREVAIL THROUGH THE FORECAST PERIOD.
HOWEVER...THE TAF SITES WILL SEE A PERIOD OF LOW AND MID LEVEL CLOUD
COVER FOR THE FIRST PART OF THE MORNING. LOWEST POTENTIAL CIGS WILL
BE DOWN TO AROUND 3K FT NEAR AND NORTH OF KJKL ALONG WITH A BRIEF
PERIOD OF MVFR POSSIBLE. WINDS WILL BE FROM THE WEST AT 10 TO 15 KTS
TO START THE DAY BEFORE SETTLING A BIT TO BETWEEN 5 AND 10 KTS
LATER IN THE DAY.
&&
.JKL WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...KAS
SHORT TERM...GREIF
LONG TERM...JMW
AVIATION...GREIF
AREA FORECAST DISCUSSION...UPDATED
NWS JACKSON KY
715 AM EST THU DEC 26 2013
.UPDATE...
ISSUED AT 715 AM EST THU DEC 26 2013
UPDATED THE GRIDS TO FINE TUNE TEMPERATURES...MAINLY MILDER...FOR THE
NEXT SEVERAL HOURS PER LATEST OBS AND TRENDS. DID ALSO ADJUST SKY
COVER TO BRING THE POST FRONTAL SC FURTHER SOUTH AND EAST FOR THE
FIRST PART OF THE MORNING...BUT STILL EXPECT THESE TO BE MOSTLY GONE
BY NOON. THE GRIDS HAVE BEEN SENT TO THE NDFD AND WEB SERVERS.
&&
.SHORT TERM...(TODAY THROUGH FRIDAY)
ISSUED AT 335 AM EST THU DEC 26 2013
07Z SFC ANALYSIS SHOWS A MOSTLY DRY COLD FRONT CROSSING EAST
KENTUCKY. THIS IS ACCOMPANIED BY A LOWER DECK OF CLOUDS AND SOME
RETURNS ON RADAR...MOSTLY VIRGA. LOWER CLOUDS...NEAR MVFR...TRAIL
THIS BOUNDARY AND WILL MOVE OVER THE NORTHERN TWO THIRDS OF THE CWA
INTO THE FIRST PART OF THE MORNING. THIS SHOULD KEEP TEMPERATURES
FROM FALLING MUCH FURTHER THROUGH THE AREA INTO DAWN. CURRENTLY THEY
VARY FROM THE UPPER 20S IN SOME VALLEYS TO THE MID 30S ON THE
RIDGES...WHILE DEWPOINTS ARE GENERALLY IN THE LOW AND MID 20S.
THE MODELS ARE IN GOOD ENOUGH AGREEMENT ALOFT THROUGH THE SHORT TERM
AS THEY ALL TAKE A SHARP SHORTWAVE NORTHEAST AND AWAY FROM THE OHIO
VALLEY TODAY. LATER...ANOTHER RIPPLE MOVES THROUGH THE BASE OF THE
RETREATING LARGE EAST CANADIAN TROUGH...PASSING HARMLESSLY THROUGH
THE AREA MIDDAY FRIDAY. HEIGHTS WILL THEN RISE OVER THE STATE AHEAD
OF A BROAD AND UNCONSOLIDATED AREA OF LOWER ONES ASSOCIATED WITH THE
POOLING ENERGY OVER SOUTH CENTRAL TEXAS. THE MODELS ARE HAVING THE
MOST DIFFICULTIES WITH THIS FEATURE AS THE NAM IS OUT OF STEP WITH
THE OTHERS IN KEEPING THE RESULTANT MID LEVEL LOW WEAKER AND A NOTCH
FURTHER EAST THAN CONSENSUS. THESE DIFFERENCES WILL AFFECT THE
FORECAST OVER THE WEEKEND...BEYOND THE SHORT TERM SO THE NAM12 WAS
PRIMARILY USED...ALONG WITH THE LATEST HRRR FOR THE NEAR TERM WX...
TO GUIDE THIS PART OF THE FORECAST.
SENSIBLE WEATHER WILL FEATURE A FLEETING CHANCE OF MAINLY FLURRIES
PASSING THROUGH FAR EAST KENTUCKY OVER THE NEXT COUPLE OF HOURS.
OTHERWISE...IT WILL BE A DRY AND QUIET FORECAST TO END THE WORK WEEK
AS SFC HIGH PRESSURE IS BUFFETED BY PASSING MID LEVEL WAVES AND
THEIR SFC REFLECTIONS TO THE NORTH OF THE AREA. THIS WILL BE NOTED
MAINLY IN TIMES OF MID AND HIGH CLOUDS BRUSHING PAST THE CWA.
TEMPERATURES THROUGH EAST KENTUCKY WILL BE SEASONABLY NEAR NORMAL
WHILE WE AWAIT THE SOUTHERN DEVELOPMENT FOR A SHOT AT A RETURN OF
PCPN LATER IN THE WEEKEND.
FOLLOWED THE CONSSHORT AND ITS BC PARTNER FOR T...TD...AND WINDS
THROUGH 12Z FRIDAY WITH SOME BLENDING IN WITH THE DIURNAL FROM THE
NAM12 FOR HOURLY TEMPS. OTHERWISE...THE CONSALL WAS USED AS A
STARTING POINT. DID ADD IN SOME MINOR RIDGE AND VALLEY TEMPERATURE
DIFFERENCES TONIGHT WHILE KEEPING POPS IN THE LOW SINGLE DIGITS AT
BEST...IN LINE WITH MOS...OUTSIDE OF THE NEXT FEW HOURS IN THE FAR
EAST.
.LONG TERM...(FRIDAY NIGHT THROUGH WEDNESDAY)
ISSUED AT 330 AM EST THU DEC 26 2013
THE BEGINNING OF THE EXTENDED PERIOD /12Z SATURDAY/ WILL HOST ZONAL
FLOW ALOFT AND SURFACE HIGH PRESSURE...MAKING FOR CLEAR SKIES IN THE
MORNING. HOWEVER...THIS SET UP WILL BE SHORT LIVED...AS TWO SYSTEMS
WILL BEGIN TO INTERACT ON EASTERN KY OVER THE NEXT 24 TO 36 HOURS.
THE FIRST OF THESE SYSTEMS...A STRONG UPPER LEVEL SHORTWAVE ACROSS
THE SOUTHERN PLAINS MOVING SLOWLY NEWARD. A SURFACE LOW PRESSURE
SYSTEM WILL DEVELOP SLIGHTLY EASTWARD OF THE UPPER TROUGH...PULLING
IN MOISTURE OFF THE GULF OF MEXICO ACROSS THE SOUTHERN STATES AND
THEN INTO SOUTHERN AND EASTERN KY SATURDAY NIGHT/SUNDAY MORNING. THE
SECOND SHORTWAVE WILL BE SLIGHTLY WEAKER...MOVING IN JUST BEHIND AND
NORTH OF THE ORIGINAL WAVE. THIS WILL PUSH A COLD FRONT ACROSS
KY FROM THE NW MONDAY EVENING/NIGHT. OF THE TWO...EXPECT THE BEST
PRECIP CHANCES AND QPF TO COME FROM THE FIRST SYSTEM...BEGINNING
RIGHT BEFORE 6Z SUNDAY AND CONTINUING THROUGH SUNDAY
AFTERNOON/EVENING. THEN THE SECOND WAVE OF MOISTURE BEGINS TO HIT KY
FROM THE NORTH AND WEST SUNDAY NIGHT INTO MONDAY. THIS TIME THE
PRECIP WILL BE LIGHTER AND SCATTERED IN NATURE.
UNFORTUNATELY...MODELS ARE STILL NOT COMPLETELY AGREEING ON THEIR
TIMING AND SET UP...SO WILL CONTINUE WITH THE ALLBLEND OUTPUT AT
THIS TIME FOR POPS.
WITH A WARM PULL FROM THE SOUTH AHEAD OF THESE TWO SYSTEMS...TEMPS
WILL RISE TO ABOVE NORMALS SATURDAY AND SUNDAY /UPPER 40S AND LOW
50S/. HOWEVER...ONCE THE COLD FRONT ACCOMPANYING THE SECOND SYSTEM
PUSHES THROUGH...IT WILL USHER IN COLDER AIR FROM THE NW.
TEMPERATURE DIFFERENCES COULD BE AS MUCH AS 15 DEGREES COOLER FROM
SUNDAY INTO MONDAY...FALLING NEAR FREEZING FOR HIGHS. THIS
TEMPERATURE DROP WILL BE WHAT GOVERNS RAIN VS. SNOW WITH THIS SECOND
SYSTEM. AT PRESENT...HAVE ALL RAIN IN FORECAST UNTIL AROUND
MIDNIGHT...AT WHICH POINT A RAIN AND SNOW MIX WILL BE
POSSIBLE...BEFORE TEMPS DROP ENOUGH TO GOVERN ALL SNOW BY 9Z.
PROLONGED TIME PERIOD FOR WHICH ACCUMULATIONS COULD OCCUR COMPARED
TO PREVIOUS FORECAST...BUT DID DROP AMOUNTS SLIGHTLY IN THE WESTERN
HALF OF THE CWA. ANYWHERE BETWEEN A DUSTING TO A COUPLE TENTHS OF AN
INCH WILL BE POSSIBLE ACROSS MUCH THE CWA...WITH THE HIGHER TERRAIN
EXPECTED TO SEE A BIT MORE...BETWEEN A HALF AN INCH TO ONE INCH.
OBVIOUSLY THIS SYSTEM IS FAIRLY FAR OUT IN THE FORECAST...SO EXPECT
THESE TOTALS TO CONTINUE TO CHANGE AS WE GET CLOSER TO THE ONSET.
WITH A TROUGHING PATTERN SETTING UP ACROSS THE EASTERN U.S...COULD
SEE SEVERAL MORE SHORTWAVES MOVE THROUGH THE TROUGH OVER THE FEW
DAYS FOLLOWING. AT THIS TIME...MODEL SOLUTIONS ARE KEEPING ANY
MOISTURE RELATED TO THESE SHORTWAVES AWAY FROM EASTERN KY. THAT
BEING SAID...TUESDAY NIGHT/WEDNESDAY MORNING WILL BE A TIME FRAME TO
WATCH...AS ANY VARIATIONS SOUTHWARD FROM WHERE THE BLENDED RUN
PLACES THE SYSTEM...KJKL COULD SEE PRECIPITATION.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z FRIDAY MORNING)
ISSUED AT 655 AM EST THU DEC 26 2013
MAINLY VFR CONDITIONS WILL PREVAIL THROUGH THE FORECAST PERIOD.
HOWEVER...THE TAF SITES WILL SEE A PERIOD OF LOW AND MID LEVEL CLOUD
COVER FOR THE FIRST PART OF THE MORNING. LOWEST POTENTIAL CIGS WILL
BE DOWN TO AROUND 3K FT NEAR AND NORTH OF KJKL ALONG WITH A BRIEF
PERIOD OF MVFR POSSIBLE. WINDS WILL BE FROM THE WEST AT 10 TO 15 KTS
TO START THE DAY BEFORE SETTLING A BIT TO BETWEEN 5 AND 10 KTS
LATER IN THE DAY.
&&
.JKL WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...GREIF
SHORT TERM...GREIF
LONG TERM...JMW
AVIATION...GREIF
AREA FORECAST DISCUSSION...UPDATED
NWS JACKSON KY
335 AM EST THU DEC 26 2013
.SHORT TERM...(TODAY THROUGH FRIDAY)
ISSUED AT 335 AM EST THU DEC 26 2013
07Z SFC ANALYSIS SHOWS A MOSTLY DRY COLD FRONT CROSSING EAST
KENTUCKY. THIS IS ACCOMPANIED BY A LOWER DECK OF CLOUDS AND SOME
RETURNS ON RADAR...MOSTLY VIRGA. LOWER CLOUDS...NEAR MVFR...TRAIL
THIS BOUNDARY AND WILL MOVE OVER THE NORTHERN TWO THIRDS OF THE CWA
INTO THE FIRST PART OF THE MORNING. THIS SHOULD KEEP TEMPERATURES
FROM FALLING MUCH FURTHER THROUGH THE AREA INTO DAWN. CURRENTLY THEY
VARY FROM THE UPPER 20S IN SOME VALLEYS TO THE MID 30S ON THE
RIDGES...WHILE DEWPOINTS ARE GENERALLY IN THE LOW AND MID 20S.
THE MODELS ARE IN GOOD ENOUGH AGREEMENT ALOFT THROUGH THE SHORT TERM
AS THEY ALL TAKE A SHARP SHORTWAVE NORTHEAST AND AWAY FROM THE OHIO
VALLEY TODAY. LATER...ANOTHER RIPPLE MOVES THROUGH THE BASE OF THE
RETREATING LARGE EAST CANADIAN TROUGH...PASSING HARMLESSLY THROUGH
THE AREA MIDDAY FRIDAY. HEIGHTS WILL THEN RISE OVER THE STATE AHEAD
OF A BROAD AND UNCONSOLIDATED AREA OF LOWER ONES ASSOCIATED WITH THE
POOLING ENERGY OVER SOUTH CENTRAL TEXAS. THE MODELS ARE HAVING THE
MOST DIFFICULTIES WITH THIS FEATURE AS THE NAM IS OUT OF STEP WITH
THE OTHERS IN KEEPING THE RESULTANT MID LEVEL LOW WEAKER AND A NOTCH
FURTHER EAST THAN CONSENSUS. THESE DIFFERENCES WILL AFFECT THE
FORECAST OVER THE WEEKEND...BEYOND THE SHORT TERM SO THE NAM12 WAS
PRIMARILY USED...ALONG WITH THE LATEST HRRR FOR THE NEAR TERM WX...
TO GUIDE THIS PART OF THE FORECAST.
SENSIBLE WEATHER WILL FEATURE A FLEETING CHANCE OF MAINLY FLURRIES
PASSING THROUGH FAR EAST KENTUCKY OVER THE NEXT COUPLE OF HOURS.
OTHERWISE...IT WILL BE A DRY AND QUIET FORECAST TO END THE WORK WEEK
AS SFC HIGH PRESSURE IS BUFFETED BY PASSING MID LEVEL WAVES AND
THEIR SFC REFLECTIONS TO THE NORTH OF THE AREA. THIS WILL BE NOTED
MAINLY IN TIMES OF MID AND HIGH CLOUDS BRUSHING PAST THE CWA.
TEMPERATURES THROUGH EAST KENTUCKY WILL BE SEASONABLY NEAR NORMAL
WHILE WE AWAIT THE SOUTHERN DEVELOPMENT FOR A SHOT AT A RETURN OF
PCPN LATER IN THE WEEKEND.
FOLLOWED THE CONSSHORT AND ITS BC PARTNER FOR T...TD...AND WINDS
THROUGH 12Z FRIDAY WITH SOME BLENDING IN WITH THE DIURNAL FROM THE
NAM12 FOR HOURLY TEMPS. OTHERWISE...THE CONSALL WAS USED AS A
STARTING POINT. DID ADD IN SOME MINOR RIDGE AND VALLEY TEMPERATURE
DIFFERENCES TONIGHT WHILE KEEPING POPS IN THE LOW SINGLE DIGITS AT
BEST...IN LINE WITH MOS...OUTSIDE OF THE NEXT FEW HOURS IN THE FAR
EAST.
.LONG TERM...(FRIDAY NIGHT THROUGH WEDNESDAY)
ISSUED AT 330 AM EST THU DEC 26 2013
THE BEGINNING OF THE EXTENDED PERIOD /12Z SATURDAY/ WILL HOST ZONAL
FLOW ALOFT AND SURFACE HIGH PRESSURE...MAKING FOR CLEAR SKIES IN THE
MORNING. HOWEVER...THIS SET UP WILL BE SHORT LIVED...AS TWO SYSTEMS
WILL BEGIN TO INTERACT ON EASTERN KY OVER THE NEXT 24 TO 36 HOURS.
THE FIRST OF THESE SYSTEMS...A STRONG UPPER LEVEL SHORTWAVE ACROSS
THE SOUTHERN PLAINS MOVING SLOWLY NEWARD. A SURFACE LOW PRESSURE
SYSTEM WILL DEVELOP SLIGHTLY EASTWARD OF THE UPPER TROUGH...PULLING
IN MOISTURE OFF THE GULF OF MEXICO ACROSS THE SOUTHERN STATES AND
THEN INTO SOUTHERN AND EASTERN KY SATURDAY NIGHT/SUNDAY MORNING. THE
SECOND SHORTWAVE WILL BE SLIGHTLY WEAKER...MOVING IN JUST BEHIND AND
NORTH OF THE ORIGINAL WAVE. THIS WILL PUSH A COLD FRONT ACROSS
KY FROM THE NW MONDAY EVENING/NIGHT. OF THE TWO...EXPECT THE BEST
PRECIP CHANCES AND QPF TO COME FROM THE FIRST SYSTEM...BEGINNING
RIGHT BEFORE 6Z SUNDAY AND CONTINUING THROUGH SUNDAY
AFTERNOON/EVENING. THEN THE SECOND WAVE OF MOISTURE BEGINS TO HIT KY
FROM THE NORTH AND WEST SUNDAY NIGHT INTO MONDAY. THIS TIME THE
PRECIP WILL BE LIGHTER AND SCATTERED IN NATURE.
UNFORTUNATELY...MODELS ARE STILL NOT COMPLETELY AGREEING ON THEIR
TIMING AND SET UP...SO WILL CONTINUE WITH THE ALLBLEND OUTPUT AT
THIS TIME FOR POPS.
WITH A WARM PULL FROM THE SOUTH AHEAD OF THESE TWO SYSTEMS...TEMPS
WILL RISE TO ABOVE NORMALS SATURDAY AND SUNDAY /UPPER 40S AND LOW
50S/. HOWEVER...ONCE THE COLD FRONT ACCOMPANYING THE SECOND SYSTEM
PUSHES THROUGH...IT WILL USHER IN COLDER AIR FROM THE NW.
TEMPERATURE DIFFERENCES COULD BE AS MUCH AS 15 DEGREES COOLER FROM
SUNDAY INTO MONDAY...FALLING NEAR FREEZING FOR HIGHS. THIS
TEMPERATURE DROP WILL BE WHAT GOVERNS RAIN VS. SNOW WITH THIS SECOND
SYSTEM. AT PRESENT...HAVE ALL RAIN IN FORECAST UNTIL AROUND
MIDNIGHT...AT WHICH POINT A RAIN AND SNOW MIX WILL BE
POSSIBLE...BEFORE TEMPS DROP ENOUGH TO GOVERN ALL SNOW BY 9Z.
PROLONGED TIME PERIOD FOR WHICH ACCUMULATIONS COULD OCCUR COMPARED
TO PREVIOUS FORECAST...BUT DID DROP AMOUNTS SLIGHTLY IN THE WESTERN
HALF OF THE CWA. ANYWHERE BETWEEN A DUSTING TO A COUPLE TENTHS OF AN
INCH WILL BE POSSIBLE ACROSS MUCH THE CWA...WITH THE HIGHER TERRAIN
EXPECTED TO SEE A BIT MORE...BETWEEN A HALF AN INCH TO ONE INCH.
OBVIOUSLY THIS SYSTEM IS FAIRLY FAR OUT IN THE FORECAST...SO EXPECT
THESE TOTALS TO CONTINUE TO CHANGE AS WE GET CLOSER TO THE ONSET.
WITH A TROUGHING PATTERN SETTING UP ACROSS THE EASTERN U.S...COULD
SEE SEVERAL MORE SHORTWAVES MOVE THROUGH THE TROUGH OVER THE FEW
DAYS FOLLOWING. AT THIS TIME...MODEL SOLUTIONS ARE KEEPING ANY
MOISTURE RELATED TO THESE SHORTWAVES AWAY FROM EASTERN KY. THAT
BEING SAID...TUESDAY NIGHT/WEDNESDAY MORNING WILL BE A TIME FRAME TO
WATCH...AS ANY VARIATIONS SOUTHWARD FROM WHERE THE BLENDED RUN
PLACES THE SYSTEM...KJKL COULD SEE PRECIPITATION.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z THURSDAY NIGHT)
ISSUED AT 105 AM EST THU DEC 26 2013
MAINLY VFR CONDITIONS WILL PREVAIL THROUGH THE FORECAST PERIOD.
HOWEVER...TAF SITES WILL SEE A PERIOD OF MID LEVEL CLOUD COVER
DURING THE REST OF THE NIGHT AS A FRONTAL BOUNDARY SLIDES THROUGH
THE AREA. LOWEST POTENTIAL CIGS WILL BE AROUND 5K FT NORTH OF KJKL.
A FEW SNOW SHOWERS WILL BE POSSIBLE GENERALLY NORTH OF THE HAL ROGERS
PARKWAY. ANY ACTIVITY SHOULD BE TOO FAR NORTH TO AFFECT KLOZ OR
KSME...THOUGH. FOR KJKL AND KSJS HAVE INCLUDED A TEMPO FOR PERIOD OF
MVFR CIG SNOW THROUGH 10Z. WINDS WILL BE SOUTHWESTERLY TO START
BEFORE VEERING TO THE WEST...NORTHWEST LATER THURSDAY AT AROUND 5 KTS
IN THE WAKE OF A PASSING FRONT.
&&
.JKL WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...GREIF
LONG TERM...JMW
AVIATION...GREIF
AREA FORECAST DISCUSSION...UPDATED
NWS JACKSON KY
105 AM EST THU DEC 26 2013
.UPDATE...
ISSUED AT 1250 AM EST THU DEC 26 2013
THE BAND OF LIGHT SNOW AND FLURRIES CONTINUES TO PUSH EAST SOUTHEAST
DEEPER INTO THE AREA. THANKS TO A LAYER OF DRY AIR AT THE SFC THIS
BAND HAS MOSTLY BEEN VIRGA. WITH THE FORECAST ON TRACK MAINLY JUST
TWEAKED LOWS THIS MORNING AND ADJUSTED THE NEXT SEVERAL HOURS OF T
AND TD GRIDS IN LINE WITH THE LATEST OBS AND TRENDS. THESE GRIDS HAVE
BEEN SENT TO THE NDFD AND WEB SERVERS.
UPDATE ISSUED AT 857 PM EST WED DEC 25 2013
RADAR RETURNS ARE INCREASING TO OUR NORTH AND A FEW SURFACE OBS HAVE
BEEN REPORTING LIGHT SNOW UNDERNEATH RECENTLY. SURFACE DEWPOINTS
HAVE TRENDED UPWARDS IN RECENT HOURS AND ARE NOW RUNNING HIGHER THAN
THE INHERITED FORECAST SO SUSPECT THERE WILL BE A LITTLE MORE
MOISTURE FOR THIS SYSTEM TO WORK WITH THAN PREVIOUSLY THOUGHT. A
RECENT HRRR RUN ALSO BROUGHT SOME SNOW SHOWERS ALL THE WAY SOUTH TO
JKL. SO...WILL INCREASE POPS A BIT OVER OUR NORTHERN TIER AND
MENTION A DUSTING POSSIBLE IN THE HWO...ALTHOUGH WITH TEMPS ABOVE
FREEZING...MINIMAL IMPACTS ARE EXPECTED.
UPDATE ISSUED AT 643 PM EST WED DEC 25 2013
WILL TWEAK THE TEMP CURVE A BIT TONIGHT AS EASTERN VALLEYS HAVE
ALREADY FALLEN BELOW FREEZING...WITH A FEW SPOTS ALREADY IN THE 20S.
I SUSPECT WE WILL EXPERIENCE OUR LOWS IN THESE VALLEYS THIS EVENING
WITH TEMPS LEVELING OFF OR EVEN RISING SEVERAL DEGREES LATER THIS
EVENING AS MID LEVEL CLOUDS MOVE OVERHEAD FROM THE WEST.
OTHERWISE...WATCHING A BAND OF WEAK RETURNS ON RADAR UP NEAR CINCY.
NO SURFACE REPORTS OF ANYTHING REACHING THE GROUND FROM THIS BUT NAM
TIME HEIGHTS SHOW LOW LEVELS MOISTENING UP ENOUGH TO JUSTIFY CURRENT
MENTION OF FLURRIES/ISOLATED SNOW SHOWERS OVER OUR NORTHERN COUNTIES
LATER TONIGHT.
&&
.SHORT TERM...(THIS EVENING THROUGH THURSDAY NIGHT)
ISSUED AT 246 PM EST WED DEC 25 2013
TEMPERATURES REBOUNDED WELL THROUGH THE DAY CLIMBING BACK INTO THE
LOWER 40S ACROSS SOUTHERN PORTIONS OF OUR CWA...MID 30S TO NEAR 40
ELSEWHERE UNDER STRONG SUNSHINE...CLEAR SKIES AND A LIGHT SOUTHERLY
RETURN FLOW.
MODELS ARE IN GOOD AGREEMENT THROUGH THE SHORT TERM PERIOD. SHORT
WAVE TROUGH WILL SWEEP ACROSS THE GREAT LAKES...OHIO VALLEY BETWEEN
NOW AND THURSDAY EVENING. CORRESPONDING SURFACE COLD FRONTAL BOUNDARY
WILL MOVE THROUGH EASTERN KENTUCKY BY EARLY THURSDAY MORNING...JUST
AFTER SUNRISE. FRONTAL FEATURES BECOME LESS DISTINCT WITH TIME. BUT
THERE WILL BE ENOUGH CLOUD COVER ASSOCIATED WITH THIS SYSTEM TO MAKE
THE OVERNIGHT LOW TEMPERATURE FORECAST MORE CHALLENGING THAN MIGHT
OTHERWISE BE. WITH DRY AIR IN PLACE DROPPED EVENING TEMPERATURES DOWN
PRETTY QUICKLY...ESPECIALLY IN OUR TYPICALLY COOLER EASTERN VALLEY
LOCATIONS. BUT TEMPERATURES SHOULD REBOUND AS CLOUDS ROLL INTO THE
AREA LATER TONIGHT. SKIES SHOULD ONCE AGAIN BEGIN TO CLEAR OUT
TOWARDS DAWN. WITH SOME WEAK CAA KICKING IN AND SKIES PARTIALLY
CLEARING TEMPS MAY DROP BACK DOWN FOR A FEW HOURS AGAIN EARLY
THURSDAY MORNING. NOT EXPECTING MUCH IN THE WAY OF PRECIPITATION WITH
THIS WEAK SYSTEM. ATTM CAN NOT RULE OUT SOME ISOLD SNOW SHOWER
ACTIVITY ALONG AND NORTH OF INTERSTATE 64 AND SOME FLURRIES IN OUR
EASTERN MOST COUNTIES. TEMPERATURE REBOUND NICELY AGAIN THURSDAY BUT
SHOULD BE JUST A COUPLE DEGREES COOLER THAN TODAY.
.LONG TERM...(FRIDAY THROUGH WEDNESDAY)
ISSUED AT 246 PM EST WED DEC 25 2013
AT THE START OF THE LONG TERM PORTION OF THE FORECAST THE UPPER
LEVEL FLOW WILL BE RELAXING WITH RISING HEIGHTS ACROSS OUR REGION.
THE NORTHERN STREAM WILL BECOME MORE ZONAL AS WE MOVE INTO THE
WEEKEND WHILE IN THE SOUTHERN STREAM A SHORT WAVE TROUGH WILL MOVE
INTO THE SOUTHERN PLAINS. AT THE SAME TIME THE CENTER OF SURFACE
HIGH PRESSURE WILL BE MOVING OFF TO OUR EAST. THIS ALL SPELLS
MODERATING TEMPERATURES AS WE MOVE INTO THE WEEKEND. YESTERDAY IT
APPEARED THAT THE SOUTHERN STREAM SYSTEM THAT MOVES INTO THE SE U.S.
THIS WEEKEND WOULD REMAIN TOO FAR SOUTH TO HAVE AN IMPACT ON OUR
LOCAL WEATHER. HOWEVER...THE 06Z AND 12Z GFS POINT TOWARDS A
PRECIPITATION CHANCE OVER AT LEAST THE SOUTHEAST PART OF THE
FORECAST AREA FROM SATURDAY NIGHT INTO SUNDAY. THIS IDEA IS
SUPPORTED BY THE 12Z ECMWF AS WELL. THE STANDARD BLENDED LOAD
PROVIDED SLIGHT CHANCE PRECIPITATION CHANCES FOR SATURDAY NIGHT IN
THE SOUTH AND CENTRAL PARTS OF THE FORECAST AREA...WITH A SLIGHT
CHANCE OVER THE CENTRAL AND EAST ON SUNDAY. WILL FOLLOW THIS IDEA.
MOST...IF NOT ALL OF ANY PRECIPITATION SHOULD BE IN THE FORM OF RAIN
SATURDAY NIGHT INTO SUNDAY...AND FOR NOW HAVE CARRIED ONLY RAIN IN THE
FORECAST. HOWEVER THERE IS AN OUTSIDE CHANCE THAT SOME VERY LIGHT
FROZEN PRECIPITATION...POSSIBLY SLEET...COULD OCCUR FOR A VERY BRIEF
PERIOD OF TIME AT PRECIPITATION ONSET LATE SATURDAY NIGHT.
THERE IS STILL GENERAL MODEL AGREEMENT WITH THE UPPER LEVEL TROUGH
DEEPENING ACROSS EASTERN NORTH AMERICA ONCE AGAIN AS WE MOVE INTO
THE EARLY PART OF NEXT WEEK. A COLD FRONT IS FORECAST TO MOVE ACROSS
THE AREA LATE SUNDAY...WITH A SLIGHT CHANCE FOR LIGHT RAIN AND SNOW
SUNDAY NIGHT AND A SLIGHT CHANCE FOR LIGHT SNOW ON MONDAY IN THE
SOUTHEAST. COLD BUT DRY CONDITIONS WILL THEN PERSIST INTO NEW YEARS
DAY.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z THURSDAY NIGHT)
ISSUED AT 105 AM EST THU DEC 26 2013
MAINLY VFR CONDITIONS WILL PREVAIL THROUGH THE FORECAST PERIOD.
HOWEVER...TAF SITES WILL SEE A PERIOD OF MID LEVEL CLOUD COVER
DURING THE REST OF THE NIGHT AS A FRONTAL BOUNDARY SLIDES THROUGH
THE AREA. LOWEST POTENTIAL CIGS WILL BE AROUND 5K FT NORTH OF KJKL.
A FEW SNOW SHOWERS WILL BE POSSIBLE GENERALLY NORTH OF THE HAL ROGERS
PARKWAY. ANY ACTIVITY SHOULD BE TOO FAR NORTH TO AFFECT KLOZ OR
KSME...THOUGH. FOR KJKL AND KSJS HAVE INCLUDED A TEMPO FOR PERIOD OF
MVFR CIG SNOW THROUGH 10Z. WINDS WILL BE SOUTHWESTERLY TO START
BEFORE VEERING TO THE WEST...NORTHWEST LATER THURSDAY AT AROUND 5 KTS
IN THE WAKE OF A PASSING FRONT.
&&
.JKL WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...GREIF
SHORT TERM...RAY
LONG TERM...SBH
AVIATION...GREIF
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
615 PM EST FRI DEC 27 2013
.SHORT TERM...(THIS EVENING THROUGH SATURDAY)
ISSUED AT 507 PM EST FRI DEC 27 2013
12Z RAOBS/LATEST WV IMAGERY AND RUC ANALYSIS SHOW NW FLOW ALF ACROSS
THE UPR GRT LKS BTWN TROFFING OVER ERN NAMERICA AND UPR RDG IN THE
ROCKIES. SW FLOW/ISENTROPIC ASCENT IN ADVANCE OF SHRTWV DIGGING SEWD
THRU ONTARIO HAS BROUGHT LOTS OF CLDS TO THE CWA. RADAR/SFC OBS
INDICATE SN IS FALLING OVER LK SUP CLOSER TO THE SHARPER ISENTROPIC
ASCENT/SHRTWV AND ACCOMPANYING SFC LO TRACK...BUT DRY WEDGE BTWN
H8-7 SHOWN ON THE 12Z INL RAOB HAS LIMITED THE COVERAGE OF THE SN
FARTHER SW OVER THE LAND CWA. OTRW...SSW LLVL FLOW HAS ADVECTED
WARMER AIR INTO UPR MI...WITH TEMPS THIS AFTN APRCHG ABV 32 AT IWD.
BUT TEMPS REMAIN WELL BLO FRZG OVER THE INTERIOR CENTRAL. THERE IS
SOME CLRG IN MN EXTENDING TOWARD WRN UPR MI WHERE THE LLVL WARMING
HAS BEEN MOST AGGRESSIVE ON THE SRN FLANK OF THE SFC LO SHIFTING
ESEWD NEAR THE MN/CNDN BORDER AND IN ADVANCE OF AN ATTENDANT LO PRES
TROF EXTENDING SWWD INTO THE ERN DAKOTAS. BUT MORE LO CLDS AND SOME
GUSTY NW WINDS FOLLOW THIS TROF FM NDAKOTA INTO MANITOBA/ADJOINING
ONTARIO. FARTHER TO THE W...A STRONG SHRTWV IS MOVING OVER THE WRN
UPR RDG INTO THE PAC NW/BRITISH COLUMBA.
MAIN FCST CONCERNS IN THE SHORT TERM ARE CLD TRENDS/POPS THIS AFTN
RELATED TO THE ONGOING WAD AHEAD OF THE APRCHG DISTURBANCE AND THEN
THE CHC FOR SOME -SN OR EVEN FREEZING DRIZZLE TNGT INTO SAT
FOLLOWING THE TROF PASSAGE.
LATE THIS AFTN/TNGT...BEST CHC FOR SOME WAD SN LATE THIS AFTN INTO
THE EVNG WL BE OVER THE ERN CWA WHERE GUIDANCE SHOWS DEEPER
SATURATION UNDER THE SHARPER ISENROPIC ASCENT DEEPER INTO THE
RETREATING COLD AIR. THE CHC POPS OVER THE ERN CWA WL SHIFT TO THE E
THIS EVNG FOLLOWING PASSAGE OF DISTURBANCE AND END OF WAD/ISENTROPIC
ASCENT. ALTHOUGH THERE WL BE SOME CLRG OVER THE W LATE THIS AFTN
INTO EARLY EVNG PER CURRENT OBS/STLT TRENDS...PASSAGE OF SFC LO PRES
TROF WL BRING A RETURN OF MORE LLVL MSTR/LO CLDS. SOME OF THE MODELS
ALSO GENERATE LGT PCPN OVER MAINLY THE W IN AREAS WHERE WNW FLOW WL
UPSLOPE DESPITE PRESENCE OF LARGER SCALE QVECTOR DVGC/DNVA/WEAK CAD
FOLLOWING THE SHRTWV. FCST SDNGS INDICATE THE MSTR WL BE CONFINED TO
THE LOWEST FEW THOUSAND FEET AND WELL BLO THE DGZ AS INCOMING
AIRMASS IS MARITIME POLAR IN ORIGIN. IN FACT...H85 TEMPS ARE FCST TO
FALL NO LOWER THAN -6C TO -8C EVEN OVER THE TIP OF THE KEWEENAW THRU
12Z SAT...TOO WARM FOR ANY LES. SO RETAINED MENTION OF SOME FREEZING
DRIZZLE AS WELL AS FINE SN/FLURRIES IN THESE UPSLOPE AREAS. AS THE
FLOW AND UPSLOPE WIND COMPONENT DIMINISHES LATE WITH ARRIVAL OF
WEAKER PRES GRADIENT...ANY -FZDZ MAY DIMINISH A BIT AS WELL. WEAKENS
DOWNSLOPE NATURE OF THE EXPECTED LLVL FLOW IN THE WAKE OF THE TROF
MAY RESULT IN SOME CLRG OVER THE SCENTRAL. OVERNGT TEMPS WL BE MUCH
WARMER THAN ON RECENT NGTS GIVEN EXPECTED CLD COVER/MODEST CHILL OF
AIRMASS. THE LOWEST MIN TEMPS ARE MOST LIKELY OVER THE SCENTRAL
WHERE MORE SUSTAINED CLRG SHUD ALLOW FOR A SHARPER TEMP DROP. SOME
FOG MAY DVLP IN THESE AREAS AS WELL WITH RELATIVELY HI SFC DEWPTS.
SAT...FOCUS SHIFTS TO TIMING/IMPACT OF SHRTWV NOW MOVING INTO THE
PAC NW AND ARPCH OF COLD FNT FM THE N. GUIDANCE SHOWS SFC COLD FNT
AND ACCOMPANYING BAND OF H85-7 FGEN SHIFTING SLOWLY S INTO THE NRN
CWA BY EARLY AFTN AS THE FLOW TURNS MORE TO THE NNE WELL TO THE S OF
COLD HI PRES BLDG THRU CENTRAL CANADA. SINCE THE MSTR IS FCST TO
STILL BE RELATIVELY SHALLOW...FREEZING DRIZZLE AS WELL AS SOME LGT
SN/FLURRIES MAY BE THE PTYPE...ESPECIALLY IN UPSLOPE AREAS NEAR LK
SUP. BUT AS THE SHRTWV TO THE W APRCHS LATER IN THE DAY...VIGOROUS
H85-5 QVECTOR CNVGC AND SOME UPR DVGC IN RRQ OF 140KT H3 JET MAX
STREAKING ACRS ONTARIO WL BRING A RETURN OF DEEPER MSTR/HIER POPS
OVER AT LEAST THE NRN TIER. EXPECT THE HIEST TEMPS AOA FRZG OVER THE
SCENTRAL...WHERE THE FNT WL NOT LIKELY PASS UNTIL AFTER 00Z SUN.
.LONG TERM...(SATURDAY NIGHT THROUGH FRIDAY)
ISSUED AT 507 PM EST FRI DEC 27 2013
SAT NIGHT...UPPER LEVEL DIV WITH THE RIGHT ENTRANCE OF THE 130KT
250-300 MB JET THROUGH NRN ONTARIO/WRN QUEBEC AND ASSOCIATED 700
MB FGEN WILL RESULT IN STRONG ENOUGH UPWARD MOTION TO SUPPORT A BAND
OF SNOW FROM NRN MN THROUGH THE NRN LAKES. THE 12Z MODELS ARE IN
GENERAL AGREEMENT WITH POSITION OF HEAVIER PCPN BAND THROUGH NRN
UPPER MI. CONSENSUS QPF AMOUNTS OF 0.15-0.30 WITH SLR VALUES IN THE
15/1 RANGE WOULD GIVE SYNOPTIC SNOW AMOUNTS OF 1 TO LOCALLY 4 INCHES
...GREATEST NORTH. IN ADDITION...CYCLONIC NE TO NNE FLOW INTO NRN
UPPER MI WILL ALSO BRING ADDITIONAL LAKE ENHANCED SNOW AMOUNTS.
SINCE SLR VALUES ONLY CLIMB NEAR 20/1 LATE SAT NIGHT WITH THE
ARRIVAL OF THE COLDER AIR...ADDITIONAL ENHANCEMENT AMOUNTS IN THE 1
TO 4 INCH RANGE WOULD KEEP OVERALL TOTAL GENERALLY IN THE ADVISORY
RANGE OR BELOW 8 INCHES. BELIEVE ONLY A FEW LOCATIONS OVER THE HURON
MTNS COULD APPROACH WARNING CRITERIA OF 8 INCHES DUE TO MORE
PROLONGED FAVORABLE UPSLOPE NE FLOW. IN ADDITION...NRLY WINDS
GUSTING TO 25 TO 30 MPH IN OPEN AREAS NEAR THE LAKE SHORES WILL
PRODUCE BLOWING AND DRIFTING SNOW.
SUN...A TRANSITION FROM LAKE ENHANCED TO PURE LES IS EXPECTED AS THE
DEEPER MOISTURE AND MID-LVL Q-VECT CONV DEPARTS E WITH MOVEMENT OF
LOW PRESSURE SYSTEM. 850 MB TEMPS DROPPING INTO THE -19C TO -22C
RANGE BY 18Z AS 850-700 MB MOISTURE STILL LINGERS OVER AREA WILL
FAVOR CONTINUED MODERATE TO HEAVY LES...ESPECIALLY FOR LOCATIONS
FAVORED BY NRLY UPSLOPE FLOW. EXPECT LES RATES TO GRADUALLY DIMINISH
IN THE AFTERNOON AS WINDS BACK AND INVERSION HEIGHTS DROP TO AROUND
5K FT. WITH EXPECTED SNOWFALL AMOUNTS GENERALLY IN HIGH END OF THE
ADVISORY RANGE...WILL CONTINUE WITH A SPS TO HIGHLIGHT THE POTENTIAL
FOR SIGNIFICANT SNOWFALL. EXPECT THE GREATEST TOTAL ACCUMULATIONS
FROM IRONWOOD THROUGH THE PORCUPINE MOUNTAINS TO ROCKLAND IN THE
WEST AND FROM HERMAN THROUGH THE HURON MOUNTAINS TO NEGAUNEE OVER
THE NORTH CENTRAL. A FEW FAVORED HIGHER TERRAIN LOCATIONS COULD
APPROACH 10 TO 12 INCHES THROUGH THE EVENT.
SUN NIGHT...ENHANCED LOW-LEVEL CONVERGENCE FROM DEVELOPING LAND
BREEZES COULD FAVOR AREAS EAST OF MQT FOR ADDITIONAL MODERATE LES
ACCUMULATION. NAM BUFR SNDGS SHOW FAVORABLE PLACEMENT OF DGZ WITHIN
BEST MODEL OMEGA OF CONVECTIVE BOUNDARY LAYER SO GOOD SNOW GROWTH
AND FLUFFY LES ACCUMULATION EXPECTED. WOULD NOT BE SURPRISED TO SEE
ADVISORY SNOWFALL OF 4 INCHES OR MORE OVER PORTIONS OF ERN
ALGER...NRN SCHOOLCRAFT AND NW LUCE COUNTY WHERE MODELS SHOW BEST
LOW-LVL CONVERGENCE.
MON-WED...AS THE POLAR VORTEX GRADUALLY SHIFTS FROM HUDSON BAY TO
NRN QUEBEC...VERY COLD ARCTIC AIR WILL DOMINATE THE WRN GREAT LAKES.
WITH 850 MB TEMPS DROPPING INTO THE -25C TO -29C RANGE...LES WILL
PERSIST FOR LOCATIONS FAVORED BY NW TO W FLOW. AS TO BE EXPECTED
MODELS STILL SHOWING DIFFERENCES WITH TIMING OF SHORTWAVES MOVING
THROUGH THE REGION AND THUS ACCOMPANYING WIND SHIFTS. THERE MAY
BE PERIODS WHERE THE WINDS ARE LIGHT ENOUGH FOR LAKE INDUCED
TROUGHING TO DOMINATE THE LOW LEVEL FLOW. THE COLD AIRMASS WILL ALSO
FAVOR SMALL SNOWFLAKES THAT WILL LIMIT OVERALL ACCUMULATIONS BUT
STILL LEAD TO LOW VISIBILITIES. OUTSIDE OF THE LES...SEVERE WIND
CHILLS AT TIMES ASE VALUES DROP INTO THE -20 TO -35 RANGE.
THU AND FRI...MODELS SHOW SIGNS OF TRENDING TOWARD LESS AMPLIFIED
PATTERN BY THE END OF THE WEEK WITH WAA DEVELOPING. SFC HIGH
PRESSURE OVER THE REGION SHOULD ENSURE MOSTLY DRY CONDITIONS ON
THURSDAY...EXCEPT FOR SOME LINGERING LIGHT WEST FLOW LES ALONG LAKE
SUPERIOR. EXPECT HIGH TEMPS THU TO REBOUND BACK INTO THE DOUBLE
DIGITS ABOVE ZERO. STRONGER WAA ON FRIDAY AHEAD OF THE NEXT
ADVANCING CLIPPER SYSTEM MAY ALLOW FOR HIGH TEMPS TO CLIMB BACK INTO
THE 20S ESPECIALLY OVER THE EAST HALF OF THE FCST AREA. BOTH THE
ECMWF AND GFS DEVELOP AREA OF LIGHT SNOW NORTH OF LAKE SUPERIOR IN
WAA/ISENTROPIC ASCENT AND SPREAD THIS SNOW ACROSS MAINLY THE EASTERN
AND NORTH CENTRAL FCST AREA. WILL INCLUDE HIGHER CHC POPS IN FRI
FCST FOR THIS SNOW POTENTIAL.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z SATURDAY EVENING)
ISSUED AT 615 PM EST FRI DEC 27 2013
TRICKY AVIATION FORECAST THIS EVENING. THE PASSAGE OF A LO PRES TROF
TNGT FOLLOWING THE PASSAGE OF THE DISTURBANCE SHOULD RESULT IN A
WSHFT TO THE WNW AND THE ARRIVAL OF SOME SHALLOW MSTR. MVFR
CONDITIONS WL BE THE RESULT EXCEPT AT CMX...WHERE MORE PRONOUNCED
UPSLOPE COMPONENT WL BRING ABOUT IFR CONDITIONS. THERE COULD ALSO BE
SOME FLURRIES AND -FZDZ AT IWD AND ESPECIALLY CMX. THESE LOWER
CONDITIONS WL PERSIST THRU SAT MRNG WITH THE ARRIVAL OF A COLD FNT.
AFTER THE COLD FRONT PASSES...NE UPSLOPE WINDS AT CMX AND SAW WILL
BRING IFR/LIFR CONDITIONS SAT AFTERNOON.
&&
.MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 507 PM EST FRI DEC 27 2013
EXPECT SW WINDS UP TO 30 KTS AND SOME FREEZING SPRAY THIS EVENING TO
DIMINISH WITH ARRIVAL OF WEAKER PRES GRADIENT ACCOMPANYING A LO PRES
PASSAGE. STRONGER N WINDS AND SOME FREEZING SPRAY WILL REDEVELOP ON
SAT FOLLOWING THE PASSAGE OF ANOTHER COLD FRONT AND AS ARCTIC AIR
SURGES S IN ADVANCE OF HI PRES BUILDING INTO SCENTRAL CANADA. AS
ARCTIC AIR FLOWS S INTO THE AREA BEHIND FRONT AND NE GRADIENT
TIGHTENS BEHIND LOW PASSING TO SOUTH LOOK FOR A PERIOD OF GALES TO
DEVELOP OVER THE WEST AND NCNTRL SAT NIGHT SO HAVE ISSUED A GALE
WATCH FOR THIS POTENTIAL. OTHERWISE NE WINDS TO 30KT WILL BE COMMON
SAT NIGHT FOR THE REST OF THE LAKE BACKING TO THE NORTH ON SUNDAY.
HEAVY FREEZING SPRAY IS STILL EXPECTED OVER MUCH OF THE LAKE SAT
NIGHT INTO MONDAY. IT APPEARS THAT THE ARCTIC AIR WILL SETTLE INTO
THE UPPER LAKES FOR AN EXTENDED STAY MUCH OF NEXT WEEK...ALTHOUGH NO
GALES APPEAR EVIDENT AT THIS POINT.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
HEAVY FREEZING SPRAY WARNING FROM 1 AM SUNDAY TO 7 AM EST MONDAY
FOR LSZ265-267.
HEAVY FREEZING SPRAY WARNING FROM 1 AM SUNDAY TO 7 PM EST MONDAY
FOR LSZ266.
GALE WATCH FROM SATURDAY EVENING THROUGH SUNDAY MORNING FOR
LSZ162-263-264.
HEAVY FREEZING SPRAY WARNING FROM 7 PM EST /6 PM CST/ SATURDAY
TO 1 AM EST /MIDNIGHT CST/ MONDAY FOR LSZ162-263-264.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...KC
LONG TERM...VOSS
AVIATION...07
MARINE...VOSS/KC
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
601 PM EST THU DEC 26 2013
.SHORT TERM...(THIS EVENING THROUGH FRIDAY)
ISSUED AT 511 PM EST THU DEC 26 2013
12Z RAOBS/LATEST WV IMAGERY AND RUC ANALYSIS SHOW UPR TROF OVER ERN
AMERICA DOWNSTREAM OF MEAN RDG OVER THE W. WNW LLVL FLOW OF H85
TEMPS AS LO AS -18C TO -20C E OF SFC RDG AXIS EXTENDING FM NE MN
INTO WI IS BRINGING MORE LES TO THE FAVORED SN BELTS. INVRN BASE
NEAR H8 AS SHOWN ON THE 12Z APX RAOB HAS SUPPORTED SOME LOCALLY HVY
SHSN OVER THE KEWEENAW AND IN ALGER COUNTY...BUT THE 12Z INL RAOB
CLOSER TO THE INCOMING SFC HI PRES RDG SHOWS A MUCH LOWER INVRN BASE
NEAR H9. SHRWV EMBEDDED IN THE NW FLOW ALF IS DROPPING SEWD THRU MN
THIS AFTN ACCOMPANIED BY BAND OF H7-3 QVECTOR CNVGC THAT IS
IMPACTING UPR MI ON THE CYC SIDE OF THIS FEATURE...BUT THE MID LVLS
ARE SO DRY WITH H85-5 QVECTOR DVGC THESE DYNAMICS APPEAR TO BE
HAVING LTL IMPACT ON THE LES. IN FACT...THE MQT VWP INDICATES THE
SUBSIDENCE INVRN HAS ACTUALLY LOWERED. CLDS ON THE NE EDGE OF THE
DEEPER MSTR ARE BRUSHING THE WI BORDER COUNTIES. BUT VSBL STLT
IMAGERY INDICATES A HEAVIER BAND OF LES PERSISTS OVER NCENTRAL
HOUGHTON COUNTY...WITH VSYBS REPORTED AS LO AS 1/2SM AT CMX. A
HEAVIER SN BAND ALSO IMPACTED ALGER COUNTY NEAR MELSTRAND EARLIER...
BUT THE WINDS HAVE BACKED ENUF TO SHIFT THIS SHSN N THRU ERN ALGER
COUNTY. FARTHER TO THE W...YET ANOTHER SHRTWV IS RIDING THRU BRITISH
COLUMBIA OVER THE WRN RDG.
MAIN FCST CONCERNS IN THE SHORT TERM ARE FOCUSED ON LES TRENDS THRU
THIS EVNG AND GOING HEADLINES.
TNGT...SHRTWV SLIDING SEWD THRU MN IS PROGGED TO REACH THE LOWER GRT
LKS THIS EVNG...LEAVING SHARP DEEP LYR QVECTOR DVGC IN ITS WAKE. IN
RESPONSE TO THE STRONG ACCOMPANYING SUBSIDENCE...INVRN BASES ARE
PROGGED TO FALL AOB 3K FT THRU THE NGT. AS THE SFC HI PRES RDG
SLIDES TO THE SE...THE LLVL FLOW IS PROGGED TO BACK SLOWLY TO THE
WSW BY 12Z FRI. THE COMBINATION OF SINKING INVRN BASE/SHIFTING WINDS
SHOULD DIMINISH THE LES THRU THE NGT...WITH THE LES LINGERING
LONGEST OVER THE N HALF OF THE KEWEENAW AND OVER THE E NEAR LK SUP
FM GRAND MARAIS TOWARD WHITEFISH POINT. OVERALL...GOING HEADLINE
EXPIRATIONS APPEAR ON TRACK...BUT THE EVNG SHIFT MAY BE ABLE TO CANX
THE ALGER/LUCE ADVY EARLY IF INCRSG LAND BREEZE CNVGC DOES NOT
INTENSIFY THE LES NEAR THE SHORE. AS FOR MIN TEMPS...EXPECT THE
LOWEST READINGS OVER THE INTERIOR SCENTRAL...WHERE SKIES WL BE MOCLR
AND WINDS LIGHTER FOR A GOOD PORTION OF THE NGT. A STRONGER S WIND
DVLPG OVER THE WRN ZNS BTWN THE DEPARTING SFC HI AND FALLING MSLP
OVER THE PLAINS AHEAD OF SHRTWV NOW TOPPING THE WRN RDG WL LIMIT THE
DIURNAL FALL THERE DESPITE A PERIOD OF MOCLR-PCLDY SKIES.
FRI...SHRTWV NOW RIDING OVER THE WRN RDG IS PROGGED TO SLIDE ESEWD
THRU ONTARIO/THE UPR LKS ON FRI AFTN...ACCOMPANIED BY A SFC LO
MOVING OVER SRN ONTARIO. WITH SOME FAIRLY SHARP ISENTROPIC ASCENT
SHOWN ON THE 290-295K SFCS /H65-8/...EXPECT INCRSG MID CLDS...
ESPECIALLY OVER THE NE HALF OF THE CWA UNDER THE SHARPER ASCENT.
THESE DYNAMICS/MODEL QPF ALSO SUPPORT GOING CHC POPS OVER THE NE CWA
CLOSER TO THE TRACK OF THE SHRTWV/SFC LO. GIVEN THE INTENSITY OF THE
ISENTROPIC LIFT...SOME H85-7 FGEN...AND THE PERSISTENT CHILL THAT
WOULD SUPPORT BETTER LIFT TO THE SW...SHIFTED THE SW EDGE OF THE
POPS A BIT TO THE SW PER THE SOMEWHAT WETTER GFS/CNDN MODELS. GIVEN
THE HI STABILITY/LLVL COLD AIR...TENDED TOWARD THE LOWER END OF
GUIDANCE FOR MAX TEMPS. EXPECT THE HIEST TEMPS NEAR FRZG OVER THE W
NEAR LK SUP...WHERE STRENGTHENING SSW WIND TO THE S OF PRES FALL
CENTER WL DOWNSLOPE.
.LONG TERM...(FRIDAY NIGHT THROUGH THURSDAY)
ISSUED AT 511 PM EST THU DEC 26 2013
AT THE BEGINNING OF THE LONG TERM...THERE WILL BE A BRIEF WARMUP AS
FLOW TEMPORARILY BECOMES ZONAL ACROSS THE NRN CONUS...ALLOWING
PACIFIC AIR TO SPREAD E. HOWEVER...A REORGANIZING AND EXPANDING
POLAR VORTEX CURRENTLY LOCATED WELL N IN NRN CANADA WILL BE
DEEPENING AS IT DROPS S TO THE VCNTY OF HUDSON BAY OVER THE NEXT 7
DAYS. EARLY NEXT WEEK...A LARGE MASS OF EXTREMELY COLD AIR WILL BE
CENTERED AROUND HUDSON BAY. MEDIUM RANGE MODELS HAVE BEEN FAIRLY
CONSISTENT SHOWING 850MB TEMPS AS LOW AS -35C TO -40C AT THE CORE OF
THE POLAR VORTEX. THE EXPANDING MASS OF ARCTIC AIR WILL SPREAD S
INTO THE GREAT LAKES NEXT WEEK...AND GIVEN THE EXTREME COLD TO THE
N...THERE MAY BE A COUPLE OF SHOTS OF BITTER COLD AIR INTO UPPER MI
DURING THE WEEK. EVOLVING PATTERN WILL NOT BE FAVORABLE FOR MUCH IN
THE WAY OF WIDESPREAD SYNOPTIC SNOWFALL OVER THE NEXT 7 DAYS. AFTER
INITIAL NE-N FLOW MODERATE LAKE EFFECT SNOW EVENT FOR SAT NIGHT INTO
SUNDAY...LES WILL THEN FOCUS OVER THE W TO NW SNOW BELT FOR MUCH OF
NEXT WEEK. LES ON MOST DAYS PROBABLY WON`T BE SIGNIFICANT AS ARCTIC
AIR WILL RESULT IN SMALL SNOWFLAKES. HOWEVER...THE SMALL SNOWFLAKES
WILL BE VERY EFFECTIVE AT REDUCING VISIBILITY. ON THE COLDEST
DAYS...WHITEOUTS WILL PROBABLY BE COMMON WHERE LES OCCURS.
BEGINNING FRI NIGHT...WAA AND 290K ISENTROPIC ASCENT WILL RESULT IN
SOME LINGERING LIGHT SNOW IN THE EVENING OVER MAINLY ERN AND
POSSIBLY OVER THE NW PORTION OF THE CWA BEFORE SNOW ENDS OVERNIGHT
WITH TRANSITION TO ISENTROPIC DESCENT. WILL CONTINUE LOW CHC 30 PCT
POPS FAR EAST WITH SCHC 20 PCT POPS OVER THE KEWEENAW. MIN TEMPS
WILL BE MAINLY IN THE UPPER TEENS TO MID 20S.
WARMER WEATHER WILL CONTINUE INTO SAT AHEAD OF A SHORTWAVE TRACKING
FROM BC/PACIFIC NW INTO THE CANADIAN HIGH PLAINS. MOST LOCATIONS
SHOULD TOP OUT NEAR 30F. HOWEVER...A COLD FRONT DRIFTING S ACROSS
UPPER MI DURING THE DAY SAT WILL HAVE AN INFLUENCE ON MAX TEMPS
DEPENDING ON ITS TIMING. UPPER DIVERGENCE ASSOCIATED WITH THE RIGHT
ENTRANCE OF UPPER JET TO THE N AND NE AND A ZONE OF MIDLEVEL
FRONTOGENESIS WILL SUPPORT A RIBBON OF -SN BEHIND THE SOUTHWARD
SAGGING COLD FRONT. THAT -SN SHOULD SPREAD S ACROSS THE NRN UPPER MI
DURING THE DAY. AS COLD FRONT CONTINUES TO DROP S SAT NIGHT...UPPER
DIVERGENCE/MID LEVEL FRONTOGENESIS AND Q-VECT CONV WILL CONTINUE TO
SUPPORT -SN. SO...EXPECT MOST OF THE FCST AREA TO SEE -SN SAT NIGHT.
LAKE ENHANCEMENT SEEMS LIKELY FOR MOST IF NOT ALL OF NRN UPPER MI
SAT NIGHT INTO SUNDAY AS WINDS SHIFT FROM NE SAT EVENING TO NRLY
LATE SAT NIGHT INTO SUNDAY. MODERATE TO OCCASIONAL HVY SNOW COULD BE
POSSIBLE OVER THE HIGHER TERRAIN OF WEST AND NORTH CENTRAL UPPER MI.
WILL CONTINUE TO HIGHLIGHT THIS SIGNIFICANT SNOW POTENTIAL IN THE
HWO. BEHIND THE FRONT...MUCH COLDER AIR WILL BEGIN TO FLOW S INTO
UPPER MI SAT NIGHT AND ESPECIALLY SUN AS 850MB TEMPS PLUMMET INTO
THE -20 TO -25C RANGE BY SUN AFTERNOON. TEMPS SHOULD SLOWLY FALL
THRU THE DAY ON SUNDAY. EXPECT LINGERING LES INTO SUN NIGHT AND SNOW
COULD BE MODERATE OVER NORTH CENTRAL UPPER MI WITH MODELS INDICATING
PERSISTENT CONVERGENT/CYCLONIC N-NNW FLOW.
PERSISTENT LES WILL THEN SET UP MON/TUE/WED...MOSTLY FOR W TO WNW
WIND FAVORED SNOWBELTS...AS ACRTIC AIR SETTLES OVER THE AREA (850MB
TEMPS GENERALLY IN THE MID TO UPPER -20S C). AT THIS POINT...IT
DOESN`T APPEAR LES ACCUMS WILL BE SIGNIFICANT DUE TO THE ARCTIC AIR
AND CONSEQUENT SMALL SNOWFLAKE SIZE. HOWEVER...IF ANY SHORTWAVES
PROVIDE ENHANCEMENT OR LAND BREEZES FOCUS CONVERGENCE...THERE MAY BE
LOCALLY HVY LES. OTHERWISE...AS PREVIOUSLY MENTIONED...THE SMALL
SNOWFLAKES WILL BE VERY EFFECTIVE AT REDUCING VISIBILITY...SO
WHITEOUTS MAY BE COMMON IN AREAS IMPACTED BY LES EARLY NEXT WEEK.
MAX TEMPS MAY STRUGGLE TO GET ABOVE 0F OVER SOME PORTIONS OF WRN
UPPER MI MON/TUE/WED. MODELS POINTING TOWARD LATE TUE FOR COLDEST
850MB TEMPS ACROSS AREA AROUND -28C. IF SO...SUBZERO HIGH TEMPS
WOULD BE COMMON OVER MUCH OF W AND CNTRL UPPER MI. WIND CHILL VALUES
WILL LIKELY FALL INTO THE ADVY RANGE AT TIMES.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z FRIDAY EVENING)
ISSUED AT 600 PM EST THU DEC 26 2013
CMX...EXPECT MVFR CONDITIONS DURING THE EVNG AS THE LLVL WINDS BACK
TOWARD THE SW AND CAUSE THE HEAVIER LES BANDS TO DRIFT TO THE N. VFR
WX SHOULD THEN DOMINATE ON FRI MRNG WITH A DRIER SW FLOW DESPITE A
GOOD DEAL OF MID CLD COVER.
IWD AND SAW...ALTHOUGH SOME MVFR CIGS MAY IMPACT SAW EARLY THIS
EVENING...EXPECT VFR WX THIS FCST PERIOD WITH A DRY W-SW FLOW TO THE
NW OF HI PRES MOVING TOWARD THE LOWER GRT LKS. WILL GET GUSTY AT
BOTH SITES LATE FRI MORNING INTO EARLY AFTERNOON AT BOTH SITES.
&&
.MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 511 PM EST THU DEC 26 2013
EXPECT WNW WINDS 15 TO 25 KTS LATE THIS AFTERNOON TO DIMINISH WITH
PASSAGE OF SFC HI PRES RDG. BUT THE SHARPENING PRES GRADIENT BETWEEN
THE DEPARTING HI AND ANOTHER LO TRACKING THRU SOUTHERN CANADA WILL
CAUSE SW WINDS TO INCREASE UP TO 25 TO 30 KTS ON FRI. EXPECT BRIEF
LULL IN WINDS LATE FRI NIGHT INTO SAT MORNING AS FRONT DRIFTS S
ACROSS THE AREA. THEN AS ARCTIC AIR FLOWS S INTO THE AREA BEHIND
FRONT...NORTH WINDS TO 30KT WILL BE COMMON SAT NIGHT/SUN...AND THERE
COULD BE A PERIOD OF GALES OVER WEST AND CENTRAL LAKE SUPERIOR.
HVY FREEZING SPRAY WILL ALSO RETURN SAT NIGHT AND WILL LIKELY
CONTINUE THRU THE MIDDLE OF NEXT WEEK AS ARCTIC AIR SETTLES INTO THE
UPPER LAKES FOR AN EXTENDED STAY.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
LAKE EFFECT SNOW ADVISORY UNTIL 1 AM EST FRIDAY FOR MIZ001-006-
007.
LAKE EFFECT SNOW ADVISORY UNTIL 7 PM EST THIS EVENING FOR MIZ002.
LAKE EFFECT SNOW WARNING UNTIL 7 PM EST THIS EVENING FOR MIZ003.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...KC
LONG TERM...VOSS
AVIATION...07
MARINE...KC/VOSS
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
512 PM EST THU DEC 26 2013
.SHORT TERM...(THIS EVENING THROUGH FRIDAY)
ISSUED AT 511 PM EST THU DEC 26 2013
12Z RAOBS/LATEST WV IMAGERY AND RUC ANALYSIS SHOW UPR TROF OVER ERN
AMERICA DOWNSTREAM OF MEAN RDG OVER THE W. WNW LLVL FLOW OF H85
TEMPS AS LO AS -18C TO -20C E OF SFC RDG AXIS EXTENDING FM NE MN
INTO WI IS BRINGING MORE LES TO THE FAVORED SN BELTS. INVRN BASE
NEAR H8 AS SHOWN ON THE 12Z APX RAOB HAS SUPPORTED SOME LOCALLY HVY
SHSN OVER THE KEWEENAW AND IN ALGER COUNTY...BUT THE 12Z INL RAOB
CLOSER TO THE INCOMING SFC HI PRES RDG SHOWS A MUCH LOWER INVRN BASE
NEAR H9. SHRWV EMBEDDED IN THE NW FLOW ALF IS DROPPING SEWD THRU MN
THIS AFTN ACCOMPANIED BY BAND OF H7-3 QVECTOR CNVGC THAT IS
IMPACTING UPR MI ON THE CYC SIDE OF THIS FEATURE...BUT THE MID LVLS
ARE SO DRY WITH H85-5 QVECTOR DVGC THESE DYNAMICS APPEAR TO BE
HAVING LTL IMPACT ON THE LES. IN FACT...THE MQT VWP INDICATES THE
SUBSIDENCE INVRN HAS ACTUALLY LOWERED. CLDS ON THE NE EDGE OF THE
DEEPER MSTR ARE BRUSHING THE WI BORDER COUNTIES. BUT VSBL STLT
IMAGERY INDICATES A HEAVIER BAND OF LES PERSISTS OVER NCENTRAL
HOUGHTON COUNTY...WITH VSYBS REPORTED AS LO AS 1/2SM AT CMX. A
HEAVIER SN BAND ALSO IMPACTED ALGER COUNTY NEAR MELSTRAND EARLIER...
BUT THE WINDS HAVE BACKED ENUF TO SHIFT THIS SHSN N THRU ERN ALGER
COUNTY. FARTHER TO THE W...YET ANOTHER SHRTWV IS RIDING THRU BRITISH
COLUMBIA OVER THE WRN RDG.
MAIN FCST CONCERNS IN THE SHORT TERM ARE FOCUSED ON LES TRENDS THRU
THIS EVNG AND GOING HEADLINES.
TNGT...SHRTWV SLIDING SEWD THRU MN IS PROGGED TO REACH THE LOWER GRT
LKS THIS EVNG...LEAVING SHARP DEEP LYR QVECTOR DVGC IN ITS WAKE. IN
RESPONSE TO THE STRONG ACCOMPANYING SUBSIDENCE...INVRN BASES ARE
PROGGED TO FALL AOB 3K FT THRU THE NGT. AS THE SFC HI PRES RDG
SLIDES TO THE SE...THE LLVL FLOW IS PROGGED TO BACK SLOWLY TO THE
WSW BY 12Z FRI. THE COMBINATION OF SINKING INVRN BASE/SHIFTING WINDS
SHOULD DIMINISH THE LES THRU THE NGT...WITH THE LES LINGERING
LONGEST OVER THE N HALF OF THE KEWEENAW AND OVER THE E NEAR LK SUP
FM GRAND MARAIS TOWARD WHITEFISH POINT. OVERALL...GOING HEADLINE
EXPIRATIONS APPEAR ON TRACK...BUT THE EVNG SHIFT MAY BE ABLE TO CANX
THE ALGER/LUCE ADVY EARLY IF INCRSG LAND BREEZE CNVGC DOES NOT
INTENSIFY THE LES NEAR THE SHORE. AS FOR MIN TEMPS...EXPECT THE
LOWEST READINGS OVER THE INTERIOR SCENTRAL...WHERE SKIES WL BE MOCLR
AND WINDS LIGHTER FOR A GOOD PORTION OF THE NGT. A STRONGER S WIND
DVLPG OVER THE WRN ZNS BTWN THE DEPARTING SFC HI AND FALLING MSLP
OVER THE PLAINS AHEAD OF SHRTWV NOW TOPPING THE WRN RDG WL LIMIT THE
DIURNAL FALL THERE DESPITE A PERIOD OF MOCLR-PCLDY SKIES.
FRI...SHRTWV NOW RIDING OVER THE WRN RDG IS PROGGED TO SLIDE ESEWD
THRU ONTARIO/THE UPR LKS ON FRI AFTN...ACCOMPANIED BY A SFC LO
MOVING OVER SRN ONTARIO. WITH SOME FAIRLY SHARP ISENTROPIC ASCENT
SHOWN ON THE 290-295K SFCS /H65-8/...EXPECT INCRSG MID CLDS...
ESPECIALLY OVER THE NE HALF OF THE CWA UNDER THE SHARPER ASCENT.
THESE DYNAMICS/MODEL QPF ALSO SUPPORT GOING CHC POPS OVER THE NE CWA
CLOSER TO THE TRACK OF THE SHRTWV/SFC LO. GIVEN THE INTENSITY OF THE
ISENTROPIC LIFT...SOME H85-7 FGEN...AND THE PERSISTENT CHILL THAT
WOULD SUPPORT BETTER LIFT TO THE SW...SHIFTED THE SW EDGE OF THE
POPS A BIT TO THE SW PER THE SOMEWHAT WETTER GFS/CNDN MODELS. GIVEN
THE HI STABILITY/LLVL COLD AIR...TENDED TOWARD THE LOWER END OF
GUIDANCE FOR MAX TEMPS. EXPECT THE HIEST TEMPS NEAR FRZG OVER THE W
NEAR LK SUP...WHERE STRENGTHENING SSW WIND TO THE S OF PRES FALL
CENTER WL DOWNSLOPE.
.LONG TERM...(FRIDAY NIGHT THROUGH THURSDAY)
ISSUED AT 511 PM EST THU DEC 26 2013
AT THE BEGINNING OF THE LONG TERM...THERE WILL BE A BRIEF WARMUP AS
FLOW TEMPORARILY BECOMES ZONAL ACROSS THE NRN CONUS...ALLOWING
PACIFIC AIR TO SPREAD E. HOWEVER...A REORGANIZING AND EXPANDING
POLAR VORTEX CURRENTLY LOCATED WELL N IN NRN CANADA WILL BE
DEEPENING AS IT DROPS S TO THE VCNTY OF HUDSON BAY OVER THE NEXT 7
DAYS. EARLY NEXT WEEK...A LARGE MASS OF EXTREMELY COLD AIR WILL BE
CENTERED AROUND HUDSON BAY. MEDIUM RANGE MODELS HAVE BEEN FAIRLY
CONSISTENT SHOWING 850MB TEMPS AS LOW AS -35C TO -40C AT THE CORE OF
THE POLAR VORTEX. THE EXPANDING MASS OF ARCTIC AIR WILL SPREAD S
INTO THE GREAT LAKES NEXT WEEK...AND GIVEN THE EXTREME COLD TO THE
N...THERE MAY BE A COUPLE OF SHOTS OF BITTER COLD AIR INTO UPPER MI
DURING THE WEEK. EVOLVING PATTERN WILL NOT BE FAVORABLE FOR MUCH IN
THE WAY OF WIDESPREAD SYNOPTIC SNOWFALL OVER THE NEXT 7 DAYS. AFTER
INITIAL NE-N FLOW MODERATE LAKE EFFECT SNOW EVENT FOR SAT NIGHT INTO
SUNDAY...LES WILL THEN FOCUS OVER THE W TO NW SNOW BELT FOR MUCH OF
NEXT WEEK. LES ON MOST DAYS PROBABLY WON`T BE SIGNIFICANT AS ARCTIC
AIR WILL RESULT IN SMALL SNOWFLAKES. HOWEVER...THE SMALL SNOWFLAKES
WILL BE VERY EFFECTIVE AT REDUCING VISIBILITY. ON THE COLDEST
DAYS...WHITEOUTS WILL PROBABLY BE COMMON WHERE LES OCCURS.
BEGINNING FRI NIGHT...WAA AND 290K ISENTROPIC ASCENT WILL RESULT IN
SOME LINGERING LIGHT SNOW IN THE EVENING OVER MAINLY ERN AND
POSSIBLY OVER THE NW PORTION OF THE CWA BEFORE SNOW ENDS OVERNIGHT
WITH TRANSITION TO ISENTROPIC DESCENT. WILL CONTINUE LOW CHC 30 PCT
POPS FAR EAST WITH SCHC 20 PCT POPS OVER THE KEWEENAW. MIN TEMPS
WILL BE MAINLY IN THE UPPER TEENS TO MID 20S.
WARMER WEATHER WILL CONTINUE INTO SAT AHEAD OF A SHORTWAVE TRACKING
FROM BC/PACIFIC NW INTO THE CANADIAN HIGH PLAINS. MOST LOCATIONS
SHOULD TOP OUT NEAR 30F. HOWEVER...A COLD FRONT DRIFTING S ACROSS
UPPER MI DURING THE DAY SAT WILL HAVE AN INFLUENCE ON MAX TEMPS
DEPENDING ON ITS TIMING. UPPER DIVERGENCE ASSOCIATED WITH THE RIGHT
ENTRANCE OF UPPER JET TO THE N AND NE AND A ZONE OF MIDLEVEL
FRONTOGENESIS WILL SUPPORT A RIBBON OF -SN BEHIND THE SOUTHWARD
SAGGING COLD FRONT. THAT -SN SHOULD SPREAD S ACROSS THE NRN UPPER MI
DURING THE DAY. AS COLD FRONT CONTINUES TO DROP S SAT NIGHT...UPPER
DIVERGENCE/MID LEVEL FRONTOGENESIS AND Q-VECT CONV WILL CONTINUE TO
SUPPORT -SN. SO...EXPECT MOST OF THE FCST AREA TO SEE -SN SAT NIGHT.
LAKE ENHANCEMENT SEEMS LIKELY FOR MOST IF NOT ALL OF NRN UPPER MI
SAT NIGHT INTO SUNDAY AS WINDS SHIFT FROM NE SAT EVENING TO NRLY
LATE SAT NIGHT INTO SUNDAY. MODERATE TO OCCASIONAL HVY SNOW COULD BE
POSSIBLE OVER THE HIGHER TERRAIN OF WEST AND NORTH CENTRAL UPPER MI.
WILL CONTINUE TO HIGHLIGHT THIS SIGNIFICANT SNOW POTENTIAL IN THE
HWO. BEHIND THE FRONT...MUCH COLDER AIR WILL BEGIN TO FLOW S INTO
UPPER MI SAT NIGHT AND ESPECIALLY SUN AS 850MB TEMPS PLUMMET INTO
THE -20 TO -25C RANGE BY SUN AFTERNOON. TEMPS SHOULD SLOWLY FALL
THRU THE DAY ON SUNDAY. EXPECT LINGERING LES INTO SUN NIGHT AND SNOW
COULD BE MODERATE OVER NORTH CENTRAL UPPER MI WITH MODELS INDICATING
PERSISTENT CONVERGENT/CYCLONIC N-NNW FLOW.
PERSISTENT LES WILL THEN SET UP MON/TUE/WED...MOSTLY FOR W TO WNW
WIND FAVORED SNOWBELTS...AS ACRTIC AIR SETTLES OVER THE AREA (850MB
TEMPS GENERALLY IN THE MID TO UPPER -20S C). AT THIS POINT...IT
DOESN`T APPEAR LES ACCUMS WILL BE SIGNIFICANT DUE TO THE ARCTIC AIR
AND CONSEQUENT SMALL SNOWFLAKE SIZE. HOWEVER...IF ANY SHORTWAVES
PROVIDE ENHANCEMENT OR LAND BREEZES FOCUS CONVERGENCE...THERE MAY BE
LOCALLY HVY LES. OTHERWISE...AS PREVIOUSLY MENTIONED...THE SMALL
SNOWFLAKES WILL BE VERY EFFECTIVE AT REDUCING VISIBILITY...SO
WHITEOUTS MAY BE COMMON IN AREAS IMPACTED BY LES EARLY NEXT WEEK.
MAX TEMPS MAY STRUGGLE TO GET ABOVE 0F OVER SOME PORTIONS OF WRN
UPPER MI MON/TUE/WED. MODELS POINTING TOWARD LATE TUE FOR COLDEST
850MB TEMPS ACROSS AREA AROUND -28C. IF SO...SUBZERO HIGH TEMPS
WOULD BE COMMON OVER MUCH OF W AND CNTRL UPPER MI. WIND CHILL VALUES
WILL LIKELY FALL INTO THE ADVY RANGE AT TIMES.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z FRIDAY AFTERNOON)
ISSUED AT 1220 PM EST THU DEC 26 2013
CMX...EXPECT IFR CONDITIONS TO PREDOMINATE INTO THIS EVNG UNDER SOME
HEAVIER LES BANDS. VSBYS INTO MID AFTN WL FALL TO LIFR AT TIMES
UNDER A HEAVY BAND SHOWN ON VSBL STLT IMAGERY. CONDITIONS WL THEN
IMPROVE TO MVFR DURING THE EVNG AS THE LLVL WINDS BACK TOWARD THE SW
AND CAUSE THE HEAVIER LES BANDS TO DRIFT TO THE N. VFR WX SHOULD
THEN DOMINATE ON FRI MRNG WITH A DRIER SW FLOW DESPITE A GOOD DEAL
OF MID CLD COVER.
IWD AND SAW...ALTHOUGH SOME MVFR CIGS MAY IMPACT SAW AT TIMES THIS
AFTN...EXPECT VFR WX THIS FCST PERIOD WITH A DRY W-SW FLOW TO THE NW
OF HI PRES MOVING TOWARD THE LOWER GRT LKS.
&&
.MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 511 PM EST THU DEC 26 2013
EXPECT WNW WINDS 15 TO 25 KTS LATE THIS AFTERNOON TO DIMINISH WITH
PASSAGE OF SFC HI PRES RDG. BUT THE SHARPENING PRES GRADIENT BETWEEN
THE DEPARTING HI AND ANOTHER LO TRACKING THRU SOUTHERN CANADA WILL
CAUSE SW WINDS TO INCREASE UP TO 25 TO 30 KTS ON FRI. EXPECT BRIEF
LULL IN WINDS LATE FRI NIGHT INTO SAT MORNING AS FRONT DRIFTS S
ACROSS THE AREA. THEN AS ARCTIC AIR FLOWS S INTO THE AREA BEHIND
FRONT...NORTH WINDS TO 30KT WILL BE COMMON SAT NIGHT/SUN...AND THERE
COULD BE A PERIOD OF GALES OVER WEST AND CENTRAL LAKE SUPERIOR.
HVY FREEZING SPRAY WILL ALSO RETURN SAT NIGHT AND WILL LIKELY
CONTINUE THRU THE MIDDLE OF NEXT WEEK AS ARCTIC AIR SETTLES INTO THE
UPPER LAKES FOR AN EXTENDED STAY.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
LAKE EFFECT SNOW ADVISORY UNTIL 1 AM EST FRIDAY FOR MIZ001-006-
007.
LAKE EFFECT SNOW ADVISORY UNTIL 7 PM EST THIS EVENING FOR MIZ002.
LAKE EFFECT SNOW WARNING UNTIL 7 PM EST THIS EVENING FOR MIZ003.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...KC
LONG TERM...VOSS
AVIATION...KC
MARINE...KC/VOSS
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
1243 AM EST THU DEC 26 2013
.SHORT TERM...(THIS EVENING THROUGH THURSDAY)
ISSUED AT 446 PM EST WED DEC 25 2013
12Z RAOBS/LATEST WV IMAGERY AND RUC ANALYSIS SHOW UPR TROF CENTERED
OVER CENTRAL NAMERICA BTWN RDGING OVER THE ERN CONUS EXTENDING INTO
QUEBEC AND A STRONGER MEAN RDG OVER THE W. VERY CHILLY AIR LINGERS
OVER THE UPR LKS WITH H85 TEMPS IN THE -15C TO -20C RANGE. THERE ARE
SEVERAL SHRTWVS OF INTEREST EMBEDDED WITHIN THIS UPR TROF. THE FIRST
IS MOVING INTO WRN UPR MI EARLY THIS AFTN AND ACCOMPANIED BY AN AREA
OF COLDER CLD TOPS SHOWN ON IR STLT IMAGERY. IN CONCERT WITH SOME
DEEPER MSTR TO H5 SHOWN ON THE 12Z INL RAOB...SCT-NMRS -SHSN
IMPACTED MUCH OF THE CWA INTO EARLY THIS AFTN BEFORE LARGER SCALE
FORCING ASSOCIATED WITH THE SHRTWV THAT CAUSED THE SN LAST NGT/THIS
MRNG EXITED THE AREA. BUT LARGER SCALE QVECTOR DVGC HAS WEAKENED
THIS SHRTWV/WARMED CLD TOP TEMPS...DIMINISHING THE SHSN DURING THE
LAST COUPLE OF HRS. IN FACT...THERE HAS BEEN SOME CLRG THIS AFTN. A
SECOND SHRTWV IS DIGGING SSEWD THRU MANITOBA...ACCOMPANIED BY A
120KT H3 JET MAX. YET ANOTHER SHRTWV RIDING OVER THE TOP OF THE WRN
RDG IS PUSHING INTO BRITISH COLUMBIA.
MAIN FCST CONCERNS IN THE SHORT TERM ARE POPS/SN AMNTS/NEED FOR
HEADLINES ASSOCIATED WITH PARADE OF SHRTWS PASSING THRU THE UPR LKS
WITHIN THE PERSISTENT UPR TROF.
TNGT...AS SHRTWV DIGGING SEWD THRU MANITOBA PASSES INTO WI
TNGT...EXPECT A WSHFT TO THE NW TO DRIVE A LO PRES TROF ONSHORE.
ALTHOUGH THE 12Z NAM/GFS SHOW THE SHARPEST DPVA/H7-3 QVECTOR CNVGC
PASSING TO THE SW OF THE CWA CLOSER TO THE ACCOMPANYING H3 JET
CORE...NAM FCST SDNGS SHOW INVRN BASE AT CMX RISING TO NEAR 7K FT
THIS EVNG IN THE PRESENCE OF DEEPER MSTR. WITH VERY COLD LLVL AIR
LINGERING NEAR THE SFC...THE SFC WSHFT FM THE WSW OVER THE INTERIOR
WL NOT BE AS DRAMATIC AS OVER/NEAR LK SUP. THE RESULT WL BE
SHARPENED LAND BREEZE LLVL CNVGC NEAR LK SUP...FIRST OVER THE NW CWA
THIS EVNG AND THEN ALSO OVER THE FAR ERN CWA LATER. SINCE THE
ACCOMPANYING UVV IS CENTERED WITHIN THE DGZ AS SHOWN ON NAM FCST
SDNGS...SN/WATER RATIOS SHOULD BE AS HI AS 25-30:1. RELATIVELY LGT
WINDS NO HIER THAN 10-15 KTS SHOULD RESULT IN MINIMAL FRACTURING OF
THE SN FLAKES. CONSIDERING THE FRBL SN/WATER RATIOS AND POTENTIAL
FOR ENHANCED SN NEAR LAND BREEZE CNVGC ZONES...OPTED TO ISSUE AN LES
ADVY FOR THE KEWEENAW AND ALGER/LUCE COUNTIES FOR MAINLY THE AREAS
NEAR LK SUP E FM GRAND MARAIS TO CRISP POINT. ALSO CONCERNED AT
LEAST NORTHERN ONTONAGON COUNTY COULD SEE SOME HEAVIER SN TNGT...
BUT OPTED NOT TO INCLUDE THAT ZONE IN THE HEADLINE SINCE HEAVIER SN
IS LIKELY TO IMPACT ONLY THE RELATIVELY UNPOPULATED NRN PORTION OF
THIS COUNTY. SINCE THERE HAS BEEN PARTIAL CLRG OVER MUCH OF THE CWA
LATE THIS AFTN...OPTED TO LOWER MIN TEMPS A BIT WITH THE EXPECTATION
TEMPS COULD FALL QUICKLY BEFORE A WSHFT TOWARD THE NW ABV THE
SHALLOW COLD AIR NEAR THE SFC BRINGS IN MORE CLDS. BACKING LLVL FLOW
LATE AHEAD OF APRCHG HI PRES RDG/SHRTWV RDG FOLLOWING THE DEPARTING
DIGGING SHRTWV MAY BRING SOME PARTIAL CLRG/MORE UNMODIFIED ARCTIC
AIR TO THE INTERIOR W NEAR THE WI BORDER AS WELL.
THU...NEXT SHRTWV NOW TOPPING UPR RDG OVER WRN CANADA IS PROGGED TO
DIG SEWD THRU MN IN PERSISTENT NW FLOW ALF...WITH SHARPEST DEEP LYR
QVECTOR CNVGC PASSING TO THE SW OF UPR MI. LLVL WINDS ARE FCST TO
BACK SLOWLY TOWARD THE WSW OVER MAINLY THE WRN CWA THRU THE DAY
AHEAD OF THIS DISTURBANCE...SO LES SHOULD BECOME CONFINED TO MAINLY
THE KEWEENAW. ALTHOUGH SN TOTALS OVER KEWEENAW COUNTY TNGT MAY NOT
BE AS IMPRESSIVE AS IN HOUGHTON COUNTY...THE NRN PORTION OF THE
KEWEENAW WL LIKELY SEE MORE SN ON THU...ESPECIALLY LATER IN THE DAY.
WITH A MORE 300 DEGREE FLOW LINGERING THRU MUCH OF THE DAY TO THE
E...EXPECT THE MOST WDSPRD AND HEAVIER LES TO IMPACT ERN ALGER AND
THE THE N HALF OF LUCE COUNTY. OVER THE SCENTRAL...ARRIVAL OF HI
PRES RDG AHEAD OF THE SHRTWV WL BRING PARTIAL SUNSHINE FILTERED BY
MID/HI CLDS ASSOCIATED WITH THE MSTR STARVED SHRTWV.
.LONG TERM...(THURSDAY NIGHT THROUGH WEDNESDAY)
ISSUED AT 446 PM EST WED DEC 25 2013
THURSDAY NIGHT...WITH PASSAGE OF SFC RIDGE...LINGERING LES WILL END
AS WINDS SHIFT SW/OFFSHORE. EXPECT LES WITH THE STRONGER LOW LEVEL CONV
OVER THE FAR NORTHEAST CWA...PER HIGH RES MODELS...COULD STILL
PRODUCE A FEW MORE INCHES OF SNOW. HOWEVER...THE SNOW OVER THE
KEWEENAW SHOULD GENERALLY BE LIGHT...WITH AN INCH OR LESS.
FRIDAY INTO FRI NIGHT...WAA WILL DOMINATE WITH A TEMPORARY
TRANSITION TOWARD A MORE ZONAL PATTERN. THERE MAY BE PERIOD OF LIGHT
PCPN ASSOCIATED WITH ISENTROPIC LIFT THROUGH THE 850-700 MB FRONTAL
ZONE. THE DEEPEST MOISTURE AND BEST CHANCE FOR SATURATION WITH
MEASURABLE PCPN IS EXPECTED FROM THE KEWEENAW INTO THE NE CWA. THERE
MAY BE ENOUGH OF A WARM LAYER...PER NAM/GFS...FOR SOME LIGHT MIXED
PCPN. HOWEVER GIVEN MODEL DIFFERENCES COMAPRED TO THE COLDER
ECMWF...CONFIDENCE WAS NOT HIGH ENOUGH TO INCLUDE ANY SLEET OR FREEZING
RAIN AT THIS TIME.
SAT THROUGH SAT NIGHT...WARMING WILL CONTINUE AHEAD OF A SHRTWV
TRACKING FROM BC NW TO THE NRN PLAINS. MOST LOCATIONS SHOULD CLIMB
TO NEAR 30. HOWEVER...A COLD FRONT DRIFTING SOUTH ACROSS THE CWA MAY
INFLUENCE MAX TEMPS DEPENING ON HOW QUICKLY IT MOVES N-S THROUGH THE
AREA FROM THE LATE MORNING THROUGH THE AFTERNOON. MODEL DIFFERENCES
REMAIN REGARDING THE STRENGTH/TIMING OF THE SHRTWV AND SFC TROUGH
DEVELOPMENT TO THE SOUTH. AFTER THE ARCTIC COLD FRONT MOVES THROUGH
WITH 850 MB TEMPS DROPPING TO AROUND -18C BY 12Z/SUN...LAKE ENHANCED
TO LES WILL DEVELOP. A PERIOD OF MODERATE TO EVEN HEAVY SNOW MAY BE
POSSIBLE FOR NORTH FLOW FAVORED SNOWBELTS IF THE STRONGER
SHRTWV/TROUGH DEVELOPS.
SUN-WED...AFTER WINDS GRADUALLY BACK ON SUN AS HIGH PRES BUILDS
TOWARD THE AREA...PERSISTENT LES WILL THEN DEVELOP FROM SUN THROUGH
TUE...MOSTLY FOR W TO WNW WIND FAVORED SNOWBELTS...AS ACRTIC AIR
SETTLES OVER THE AREA WITH 850 MB TEMPS TO AROUND -25C. BY WED THERE
IS MORE UNCERTAINTY WITH THE WIND DIRECTION GIVEN THE POTENTIAL FOR
CLIPPER SHRTWVS(ECMWF) THAT MAY BRING BACKING WINDS.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z THURSDAY NIGHT)
ISSUED AT 1240 AM EST THU DEC 26 2013
CMX...EXPECT PREDOMINANT MVFR CONDITIONS THROUGH THE PERIOD WITH
LAKE EFFECT SNOW SHOWERS. THERE WILL BE BRIEF TIMES IFR VIS WILL BE
IN THERE...ESPECIALLY THU NIGHT.
IWD...MVFR CONDITIONS WL IMPROVE TO VFR ON THU AFTERNOON WITH THE
APRCH OF A HI PRES RDG/ BACKING LLVL FLOW.
SAW...EXPECT MVFR CIGS TNGT ASSOCIATED WITH A LO PRES TROF PASSAGE.
VFR WX SHOULD THEN FOLLOW THU WITH A DOWNSLOPE W WIND FOLLOWING THE
TROF.
&&
.MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 446 PM EST WED DEC 25 2013
EXPECT W TO NW WINDS UP TO 25 KTS TONIGHT TO DIMINISH TO UNDER 20
KTS ON THU WITH APPROACH OF A HI PRES RIDGE/WEAKER PRES GRADIENT.
FOLLOWING THE PASSAGE OF AN ARCTIC COLD FRONT...NORTH GALES ARE
POSSIBLE SATURDAY NIGHT INTO SUNDAY. HEAVY FREEZING SPRAY IS ALSO
EXPECTED FROM SATURDAY NIGHT INTO TUESDAY. &&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
LAKE EFFECT SNOW ADVISORY UNTIL 7 PM EST THIS EVENING FOR MIZ006-
007.
LAKE EFFECT SNOW WARNING UNTIL 1 PM EST THIS AFTERNOON FOR
MIZ002.
LAKE EFFECT SNOW WARNING UNTIL 7 PM EST THIS EVENING FOR MIZ001-
003.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...KC
LONG TERM...JLB
AVIATION...07
MARINE...KC
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
1156 PM EST WED DEC 25 2013
.SHORT TERM...(THIS EVENING THROUGH THURSDAY)
ISSUED AT 446 PM EST WED DEC 25 2013
12Z RAOBS/LATEST WV IMAGERY AND RUC ANALYSIS SHOW UPR TROF CENTERED
OVER CENTRAL NAMERICA BTWN RDGING OVER THE ERN CONUS EXTENDING INTO
QUEBEC AND A STRONGER MEAN RDG OVER THE W. VERY CHILLY AIR LINGERS
OVER THE UPR LKS WITH H85 TEMPS IN THE -15C TO -20C RANGE. THERE ARE
SEVERAL SHRTWVS OF INTEREST EMBEDDED WITHIN THIS UPR TROF. THE FIRST
IS MOVING INTO WRN UPR MI EARLY THIS AFTN AND ACCOMPANIED BY AN AREA
OF COLDER CLD TOPS SHOWN ON IR STLT IMAGERY. IN CONCERT WITH SOME
DEEPER MSTR TO H5 SHOWN ON THE 12Z INL RAOB...SCT-NMRS -SHSN
IMPACTED MUCH OF THE CWA INTO EARLY THIS AFTN BEFORE LARGER SCALE
FORCING ASSOCIATED WITH THE SHRTWV THAT CAUSED THE SN LAST NGT/THIS
MRNG EXITED THE AREA. BUT LARGER SCALE QVECTOR DVGC HAS WEAKENED
THIS SHRTWV/WARMED CLD TOP TEMPS...DIMINISHING THE SHSN DURING THE
LAST COUPLE OF HRS. IN FACT...THERE HAS BEEN SOME CLRG THIS AFTN. A
SECOND SHRTWV IS DIGGING SSEWD THRU MANITOBA...ACCOMPANIED BY A
120KT H3 JET MAX. YET ANOTHER SHRTWV RIDING OVER THE TOP OF THE WRN
RDG IS PUSHING INTO BRITISH COLUMBIA.
MAIN FCST CONCERNS IN THE SHORT TERM ARE POPS/SN AMNTS/NEED FOR
HEADLINES ASSOCIATED WITH PARADE OF SHRTWS PASSING THRU THE UPR LKS
WITHIN THE PERSISTENT UPR TROF.
TNGT...AS SHRTWV DIGGING SEWD THRU MANITOBA PASSES INTO WI
TNGT...EXPECT A WSHFT TO THE NW TO DRIVE A LO PRES TROF ONSHORE.
ALTHOUGH THE 12Z NAM/GFS SHOW THE SHARPEST DPVA/H7-3 QVECTOR CNVGC
PASSING TO THE SW OF THE CWA CLOSER TO THE ACCOMPANYING H3 JET
CORE...NAM FCST SDNGS SHOW INVRN BASE AT CMX RISING TO NEAR 7K FT
THIS EVNG IN THE PRESENCE OF DEEPER MSTR. WITH VERY COLD LLVL AIR
LINGERING NEAR THE SFC...THE SFC WSHFT FM THE WSW OVER THE INTERIOR
WL NOT BE AS DRAMATIC AS OVER/NEAR LK SUP. THE RESULT WL BE
SHARPENED LAND BREEZE LLVL CNVGC NEAR LK SUP...FIRST OVER THE NW CWA
THIS EVNG AND THEN ALSO OVER THE FAR ERN CWA LATER. SINCE THE
ACCOMPANYING UVV IS CENTERED WITHIN THE DGZ AS SHOWN ON NAM FCST
SDNGS...SN/WATER RATIOS SHOULD BE AS HI AS 25-30:1. RELATIVELY LGT
WINDS NO HIER THAN 10-15 KTS SHOULD RESULT IN MINIMAL FRACTURING OF
THE SN FLAKES. CONSIDERING THE FRBL SN/WATER RATIOS AND POTENTIAL
FOR ENHANCED SN NEAR LAND BREEZE CNVGC ZONES...OPTED TO ISSUE AN LES
ADVY FOR THE KEWEENAW AND ALGER/LUCE COUNTIES FOR MAINLY THE AREAS
NEAR LK SUP E FM GRAND MARAIS TO CRISP POINT. ALSO CONCERNED AT
LEAST NORTHERN ONTONAGON COUNTY COULD SEE SOME HEAVIER SN TNGT...
BUT OPTED NOT TO INCLUDE THAT ZONE IN THE HEADLINE SINCE HEAVIER SN
IS LIKELY TO IMPACT ONLY THE RELATIVELY UNPOPULATED NRN PORTION OF
THIS COUNTY. SINCE THERE HAS BEEN PARTIAL CLRG OVER MUCH OF THE CWA
LATE THIS AFTN...OPTED TO LOWER MIN TEMPS A BIT WITH THE EXPECTATION
TEMPS COULD FALL QUICKLY BEFORE A WSHFT TOWARD THE NW ABV THE
SHALLOW COLD AIR NEAR THE SFC BRINGS IN MORE CLDS. BACKING LLVL FLOW
LATE AHEAD OF APRCHG HI PRES RDG/SHRTWV RDG FOLLOWING THE DEPARTING
DIGGING SHRTWV MAY BRING SOME PARTIAL CLRG/MORE UNMODIFIED ARCTIC
AIR TO THE INTERIOR W NEAR THE WI BORDER AS WELL.
THU...NEXT SHRTWV NOW TOPPING UPR RDG OVER WRN CANADA IS PROGGED TO
DIG SEWD THRU MN IN PERSISTENT NW FLOW ALF...WITH SHARPEST DEEP LYR
QVECTOR CNVGC PASSING TO THE SW OF UPR MI. LLVL WINDS ARE FCST TO
BACK SLOWLY TOWARD THE WSW OVER MAINLY THE WRN CWA THRU THE DAY
AHEAD OF THIS DISTURBANCE...SO LES SHOULD BECOME CONFINED TO MAINLY
THE KEWEENAW. ALTHOUGH SN TOTALS OVER KEWEENAW COUNTY TNGT MAY NOT
BE AS IMPRESSIVE AS IN HOUGHTON COUNTY...THE NRN PORTION OF THE
KEWEENAW WL LIKELY SEE MORE SN ON THU...ESPECIALLY LATER IN THE DAY.
WITH A MORE 300 DEGREE FLOW LINGERING THRU MUCH OF THE DAY TO THE
E...EXPECT THE MOST WDSPRD AND HEAVIER LES TO IMPACT ERN ALGER AND
THE THE N HALF OF LUCE COUNTY. OVER THE SCENTRAL...ARRIVAL OF HI
PRES RDG AHEAD OF THE SHRTWV WL BRING PARTIAL SUNSHINE FILTERED BY
MID/HI CLDS ASSOCIATED WITH THE MSTR STARVED SHRTWV.
.LONG TERM...(THURSDAY NIGHT THROUGH WEDNESDAY)
ISSUED AT 446 PM EST WED DEC 25 2013
THURSDAY NIGHT...WITH PASSAGE OF SFC RIDGE...LINGERING LES WILL END
AS WINDS SHIFT SW/OFFSHORE. EXPECT LES WITH THE STRONGER LOW LEVEL CONV
OVER THE FAR NORTHEAST CWA...PER HIGH RES MODELS...COULD STILL
PRODUCE A FEW MORE INCHES OF SNOW. HOWEVER...THE SNOW OVER THE
KEWEENAW SHOULD GENERALLY BE LIGHT...WITH AN INCH OR LESS.
FRIDAY INTO FRI NIGHT...WAA WILL DOMINATE WITH A TEMPORARY
TRANSITION TOWARD A MORE ZONAL PATTERN. THERE MAY BE PERIOD OF LIGHT
PCPN ASSOCIATED WITH ISENTROPIC LIFT THROUGH THE 850-700 MB FRONTAL
ZONE. THE DEEPEST MOISTURE AND BEST CHANCE FOR SATURATION WITH
MEASURABLE PCPN IS EXPECTED FROM THE KEWEENAW INTO THE NE CWA. THERE
MAY BE ENOUGH OF A WARM LAYER...PER NAM/GFS...FOR SOME LIGHT MIXED
PCPN. HOWEVER GIVEN MODEL DIFFERENCES COMAPRED TO THE COLDER
ECMWF...CONFIDENCE WAS NOT HIGH ENOUGH TO INCLUDE ANY SLEET OR FREEZING
RAIN AT THIS TIME.
SAT THROUGH SAT NIGHT...WARMING WILL CONTINUE AHEAD OF A SHRTWV
TRACKING FROM BC NW TO THE NRN PLAINS. MOST LOCATIONS SHOULD CLIMB
TO NEAR 30. HOWEVER...A COLD FRONT DRIFTING SOUTH ACROSS THE CWA MAY
INFLUENCE MAX TEMPS DEPENING ON HOW QUICKLY IT MOVES N-S THROUGH THE
AREA FROM THE LATE MORNING THROUGH THE AFTERNOON. MODEL DIFFERENCES
REMAIN REGARDING THE STRENGTH/TIMING OF THE SHRTWV AND SFC TROUGH
DEVELOPMENT TO THE SOUTH. AFTER THE ARCTIC COLD FRONT MOVES THROUGH
WITH 850 MB TEMPS DROPPING TO AROUND -18C BY 12Z/SUN...LAKE ENHANCED
TO LES WILL DEVELOP. A PERIOD OF MODERATE TO EVEN HEAVY SNOW MAY BE
POSSIBLE FOR NORTH FLOW FAVORED SNOWBELTS IF THE STRONGER
SHRTWV/TROUGH DEVELOPS.
SUN-WED...AFTER WINDS GRADUALLY BACK ON SUN AS HIGH PRES BUILDS
TOWARD THE AREA...PERSISTENT LES WILL THEN DEVELOP FROM SUN THROUGH
TUE...MOSTLY FOR W TO WNW WIND FAVORED SNOWBELTS...AS ACRTIC AIR
SETTLES OVER THE AREA WITH 850 MB TEMPS TO AROUND -25C. BY WED THERE
IS MORE UNCERTAINTY WITH THE WIND DIRECTION GIVEN THE POTENTIAL FOR
CLIPPER SHRTWVS(ECMWF) THAT MAY BRING BACKING WINDS.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z THURSDAY NIGHT)
ISSUED AT 1155 PM EST WED DEC 25 2013
CMX...EXPECT PREDOMINANT MVFR CONDITIONS THROUGH THE PERIOD WITH
LAKE EFFECT SNOW SHOWERS. THERE WILL BE BRIEF TIMES IFR VIS WILL BE
IN THERE...ESPECIALLY THU NIGHT.
IWD...MVFR CONDITIONS WL IMPROVE TO VFR ON THU AFTERNOON WITH THE
APRCH OF A HI PRES RDG/ BACKING LLVL FLOW.
SAW...EXPECT MVFR CIGS TNGT ASSOCIATED WITH A LO PRES TROF PASSAGE.
VFR WX SHOULD THEN FOLLOW THU WITH A DOWNSLOPE W WIND FOLLOWING THE
TROF.
&&
.MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 446 PM EST WED DEC 25 2013
EXPECT W TO NW WINDS UP TO 25 KTS TONIGHT TO DIMINISH TO UNDER 20
KTS ON THU WITH APPROACH OF A HI PRES RIDGE/WEAKER PRES GRADIENT.
FOLLOWING THE PASSAGE OF AN ARCTIC COLD FRONT...NORTH GALES ARE
POSSIBLE. HEAVY FREEZING SPRAY IS ALSO EXPECTED FROM SATURDAY NIGHT
INTO TUESDAY.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
LAKE EFFECT SNOW ADVISORY UNTIL 7 PM EST THURSDAY FOR MIZ006-007.
LAKE EFFECT SNOW WARNING UNTIL 1 PM EST THURSDAY FOR MIZ002.
LAKE EFFECT SNOW WARNING UNTIL 7 PM EST THURSDAY FOR MIZ001-003.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...KC
LONG TERM...JLB
AVIATION...07
MARINE...KC
AREA FORECAST DISCUSSION
NWS TWIN CITIES/CHANHASSEN MN
620 PM CST FRI DEC 27 2013
.SHORT TERM...(THIS EVENING THROUGH SATURDAY NIGHT)
ISSUED AT 308 PM CST FRI DEC 27 2013
FIRST CONCERN IS THE FORMATION OF DENSE FOG OR AT LEAST AREAS OF
FOG WITH LOCALIZED DENSE FOG OVERNIGHT. DEW POINTS HAVE INCREASED
SIGNIFICANTLY IN MN...AND UPSTREAM CONDS IN ND HAVE DEW POINTS IN
THE MID 30S. ALTHOUGH MN WILL LIKELY DROP A FEW DEGREES THIS
EVENING...WITH DEW POINTS HOLDING OR EVEN RISING A FEW
DEGREES...THE BOUNDARY LAYER WILL SATURATE AND LEAD TO FOG. THE
MAIN DILEMMA IS HOW WIDESPREAD THE FOG DEVELOPS AND WHETHER DENSE
FOG FORMS AS WINDS REMAIN ARND 5 MPH. THE BEST SCENARIO IS TO
INTRODUCE AREAS OF FOG WHERE WIND SPDS ARE LESS THAN 6 MPH
OVERNIGHT...AND SATURDAY MORNING BEFORE THE ARCTIC FRONT ARRIVES
IN THE NW CWA BY NOON.
NO MAJOR CHGS TO THE FORECAST FOR SATURDAY AFTN/EVENING AS THE
ARCTIC FRONT QUICKLY MOVES ACROSS THE CWA IN A 6 TO 9 HR PERIOD.
AS PER THE PRESSURE GRADIENT...THE LATEST MSLP CHG ACROSS THE
CWA FROM NW TO SE IS NEARLY 20 MB. THIS IS AN INCREASE OF 4 MB
FROM YESTERDAY MODEL RUNS. BASED ON THE PRESSURE GRADIENT CHG AND
THE STEEP LAPSE RATES BEHIND THE FRONT...WIND SPDS WILL QUICKLY
INCREASE TO ARND 30-35 MPH SUSTAINED IN WESTERN MN...WITH 20 TO 25
MPH IN EASTERN MN DURING THE EVENING. WITH SUSTAINED WINDS OF 30
TO 35 MPH...GUSTS WILL LIKELY APPROACH OR EXCEED 45 MPH AT TIMES
IN THE TYPICAL AREAS OF WC/SW/SC MN. THE HIGHEST WIND SPDS WILL
OCCUR ALONG THE MINNESOTA RIVER VALLEY WHERE THE ADDED FUNNEL
EFFECT COULD LEAD TO EVEN HIGHER GUSTS.
THE NEXT CONCERN IS BLIZZARD OR NEAR BLIZZARD CONDS DEVELOPING
BEHIND THIS FRONT...
IF TODAYS TEMPERATURES DID NOT RISE ABV FREEZING...OR AT LEAST
CREATE A CRUST ON THE ALREADY DEEP SNOWPACK...WE WOULD BE LOOKING
AT BLIZZARD CONDS IN WC/SW/SC MN BY LATE SATURDAY AFTN/EVENING.
WITH THE LIMITING FACTOR OF BLOWING SNOW DUE TO THE CRUST...AND
NOT MUCH SNOW FALLING WITH THIS SYSTEM...BLIZZARD CONDS MAY NOT BE
MET. HOWEVER...I HAVE SEEN THESE WIND SPDS BEFORE CREATE ITS OWN
WAY TO BREAKING UP THE SNOWPACK AND LEADING TO BLOWING SNOW. THERE
IS PLENTY OF POWDERY SNOW UNDER THE CRUST IF THE CONDS
MATERIALIZES.
IN ADDITION...AS TEMPS FALL INTO THE SINGLE DIGITS BELOW
ZERO...THESE WIND SPDS WILL CREATE WIND CHILL VALUES OF 25 TO 35
BELOW ZERO DURING THE EVENING. WIND CHILL WARNING CRITERIA WHICH
IS 35 BELOW OR LOWER...WILL LIKELY DEVELOP DURING THE EARLY
MORNING HRS OF SUNDAY AS TEMPS FALL INTO THE TEENS BELOW ZERO IN
THE NW CWA. TOO MANY SCENARIOS TO DEBATE...SO WITH MANY
UNCERTAINTIES RELATED TO THE BLOWING SNOW...AND THE LIKELIHOOD OF
DANGEROUS WIND CHILLS DEVELOPING AND THE ADDED TRAVEL DURING THE
HOLIDAY WEEKEND...A WINTER WEATHER ADVISORY WILL BE ISSUED FOR
SATURDAY AFTN...THRU SUNDAY AFTN FOR MOST OF MN. WILL ALSO
HIGHLIGHT THE POSSIBILITY OF BLIZZARD CONDS IF THE BLOWING SNOW
MATERIALIZES.
.LONG TERM...(SUNDAY THROUGH FRIDAY)
ISSUED AT 308 PM CST FRI DEC 27 2013
COLD...COLD AND COLD IS THE BEST WAY TO DESCRIBE THE EXTENDED
PORTION OF THIS FORECAST. ARCTIC AIR DROPS INTO THE REGION
STARTING SUNDAY AND WILL LAST THRU WEDNESDAY...FOLLOWED BY SOME
MODERATION GOING INTO THE END OF THE WORKWEEK. THE LARGEST
CONCERNS WILL BE SUNDAY INTO MONDAY DUE TO WIND CHILL VALUES. THE
TIGHT PRES GRADIENT BETWEEN THE DEPARTING 1010MB LOW AND AN
INCOMING 1045MB HIGH WILL CREATE STRONG WINDS FOR MUCH OF WESTERN-
CENTRAL MN...SLIGHTLY LESSER OVER ERN MN INTO WRN WI. WIND CHILLS
WILL COMMONLY BE IN THE -25 TO -35 DEG F RANGE WITH SOME LOCATIONS
IN WRN MN DROPPING TO AS LOW AS -40 DEG F NOT UNREASONABLE. ONE
WEAK SHORTWAVE DISTURBANCE WILL DRIVE THRU THE REGION MON...
POSSIBLY PRODUCING A FEW TENTHS OF AN INCH OF NEW SNOWFALL.
REINFORCING ARCTIC HIGH PRES WILL FOLLOW THIS DISTURBANCE FOR
TUE...AGAIN KEEPING HIGHS WELL BELOW ZERO ON TUE. ANOTHER
DISTURBANCE LOOKS TO PUSH THRU TUE NIGHT INTO WED...AGAIN POSSIBLY
PRODUCING MINOR SNOW ACCUMULATION. THIS SYSTEM WILL BECOME MUCH
MORE ORGANIZED OVER THE GREAT LAKES AND POINTS EWD...HELPING DRAG
DOWN THE COLD AIR ON ITS BACKSIDE. MODERATION BEGINS THU AS A
RIDGE COMING ONSHORE THE WRN CONUS SHIFTS INTO THE CENTRAL STATES
BUT FLATTENS IN RESPONSE TO AN ORGANIZED AREA OF LOW PRES DROPPING
INTO THE N-CENTRAL STATES FROM WRN CANADA. THERE IS A CHC OF
ADDITIONAL LIGHT SNOWFALL ACCUMULATION FOR FRI WITH THIS SYSTEM...
BUT AHEAD OF IT TEMPERATURES WILL MODERATE SUCH THAT HIGHS CLIMB
BACK INTO THE DOUBLE DIGITS ABOVE ZERO.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z SATURDAY EVENING)
ISSUED AT 620 PM CST FRI DEC 27 2013
MVFR CEILINGS SPREAD INTO KAXN LATE THIS AFTERNOON AHEAD OF A
COLD FRONT ACROSS NORTHERN MN. FEW SHORT TERM GUIDANCE PRODUCTS
CAPTURE THE EXPANSE OF THE MVFR CEILINGS THAT STRETCH NORTHWEST
INTO SOUTH CENTRAL CANADA. ABOUT THE BEST PROXY GOING FORWARD IS
THE RAP 925MB RH. THE RAP SUGGESTS THAT THE MVFR CEILINGS WILL
ROLL DOWN I-94 THIS EVENING...PERHAPS REACHING KMSP BY 03Z AND
INTO KRNH AND KEAU IN THE 05Z-07Z TIME FRAME. THIS SHOULD PLAY
HAVOC ON DENSE FOG FORMING AT LEAST INITIALLY ACROSS CENTRAL MN BUT
MAY NOT HELP US MUCH IN SOUTHERN MN. PROFILE DATA INDICATES A GOOD
SETUP FOR FOG TONIGHT WITH THE LOW LEVEL HYDROLAPSE INCREASING
SIGNIFICANTLY. AT THIS POINT...THE FORECAST GOING FORWARD IS OF LOW
CONFIDENCE SINCE THE MVFR CEILINGS WERE NOT A FACTOR EARLIER TODAY.
OVERALL...BROUGHT PREVAILING MVFR CEILINGS INTO ALL OF THE
TERMINALS EXCEPT KRWF DURING THE EVENING WHICH MEANT BACKING OFF
SOME ON THE LOW VSBY/FOG FORECAST. DURING THE NIGHT...THE FRONTAL
BOUNDARY WILL BOTTOM OUT IN THE TWIN CITIES AND THEN BEGIN MOVING
BACK NE AS A WARM FRONT. HENCE...TRIED TO TIME OUT THE MVFR
CEILINGS FROM SW TO NE AND ALLOW MORE FOG IN TOWARDS DAYBREAK. A
PRETTY DECENT DAY ON SATURDAY ONCE THE FOG/CEILINGS LIFT WITH
ANOTHER ABOVE FREEZING DAY IN STORE. HOWEVER...A POTENT ARCTIC
COLD FRONT WILL MOVE THROUGH KAXN EARLY IN THE AFTERNOON...REACH
KMSP BY 00Z AND KEAU BY 03Z. THIS IS ANOTHER SITUATION OF LOW
CONFIDENCE AS MODEL DATA INDICATES ONLY LOW LEVEL SATURATION WITH
THE FRONT BETWEEN 0 AND -8 DEG C WHICH IMPLIES VERY LITTLE ICE.
HENCE...IN THE WAKE OF THE FRONT THERE MAY BE A FEW HOURS OF
FREEZING DRIZZLE FOLLOWED BY A LITTLE LIGHT SNOW AS THE LOW LEVEL
SATURATION PUSHES INTO THE DENDRITIC GROWTH ZONE (-12 TO -18 DEG
C). THE ONE AREA OF HIGH CONFIDENCE IS THAT WINDS ARE GOING TO
SCREAM IN THE WAKE OF THE ARCTIC FRONT ACROSS WESTERN AND SOUTHERN
MN. SUSTAINED SPEEDS NEAR 30 KNOTS WITH GUSTS NEAR 45 KNOTS ARE
LIKELY JUST BEYOND THE END OF THE 00Z TAF FOR KAXN AND KRWF. NOW
WHETHER OR NOT THIS WILL BE ABLE TO BREAK THE CRUST ON THE SNOW
FROM TWO DAYS OF WARMING AND CAUSE A BLIZZARD REMAINS A BIG
QUESTION.
KMSP...MVFR CEILINGS MAY REACH THE AIRFIELD AROUND 03Z AND MEANDER
IN AND OUT THROUGH THE NIGHT. DEPENDING ON THE EXPANSE OF THE LOW
CEILING WILL DETERMINE HOW MUCH FOG OCCURS. CERTAINLY A LOW
CONFIDENCE FORECAST OVERNIGHT. AN ARCTIC FRONT WILL PUSH THROUGH
LATE SATURDAY AFTERNOON/EVENING. THERE COULD BE A FEW HOURS OF
FREEZING DRIZZLE FOLLOWED BY SOME LIGHT SNOW. THE BIG THING WILL
BE THE WINDS AND PLUMMETING TEMPERATURES. DURING THE OVERNIGHT
HOURS... NW WINDS NEAR 20 KNOTS GUSTING 34 KNOTS ARE LIKELY.
/OUTLOOK FOR KMSP/
SAT NIGHT...MVFR/IFR WITH -SN/BLSN. WINDS NW AT 20G30KTS. TEMPS
FALLING SHARPLY 03-06Z.
SUN...MVFR EARLY...THEN VFR. WINDS NW AT 15G20KTS. TEMPS NEAR
ZERO.
MON...VFR. WINDS SE AT 10G15KTS.
&&
.MPX WATCHES/WARNINGS/ADVISORIES...
MN...WINTER WEATHER ADVISORY FROM 3 PM SATURDAY TO 6 PM CST SUNDAY
FOR MNZ041-042-047-048-054>056.
WINTER WEATHER ADVISORY FROM 6 PM SATURDAY TO 6 PM CST SUNDAY
FOR MNZ049-057-058-064>067-073>076-082>085-091>093.
WI...NONE.
&&
$$
SHORT TERM...JLT
LONG TERM...JPC
AVIATION...RAH
AREA FORECAST DISCUSSION...UPDATED
NWS TWIN CITIES/CHANHASSEN MN
1213 PM CST THU DEC 26 2013
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 348 AM CST THU DEC 26 2013
WE CONTINUE TO FIND OURSELVES WITHIN MOIST CYCLONIC NORTHWEST FLOW
THIS MORNING...WITH CLOUDS AND BOUTS OF FLURRIES/LIGHT SNOW
CONTINUING TO DOMINATE THE NRN PLAINS AND UPPER MS VALLEY. THE TWO
FEATURES OF INTEREST THIS MORNING ARE THE STRONG UPPER WAVE
CURRENTLY VISIBLE IN WATER VAPOR IMAGERY MOVING ACROSS THE DAKOTAS
AND A WARM/STATIONARY FRONT THAT IS MORE OR LESS LINED UP WITH THE
MN RIVER FROM WC INTO SE MN. CURRENT THINKING IS THAT THIS FRONT
WILL ACT AS A FOCUS FOR A HEAVIER BAND OF PRECIP FROM ABOUT 15Z-21Z
TODAY. BASED POP/QPF GRIDS FOR THIS BAND OF SNOW ON THE GFS AND
SREF...WHICH RESULTED IN THE BAND COMING DOWN BETWEEN I-94 AND THE
MN RIVER. THOUGH CATEGORICAL POPS HAVE BEEN RETAINED...THE HRRR AND
HOPWRF MEMBERS ALONG THE THE NAM/GEM SHOW VERY LITTLE SNOW COMING
DOWN ALONG THIS FRONT...INSTEAD TAKING MOST OF IT ACROSS NRN MN WITH
THE BRUNT OF THE FORCING WITH THE UPPER WAVE...SO WOULD NOT BE
SURPRISED IF THESE POPS END UP BEING OVERDONE. THIS LOOKS TO BE A
FAIRLY TRANSIENT FEATURE WHICH MEANS IT IS ONLY EXPECTED TO BRING A
DUSTING TO ONE INCH OF SNOW. FOR THIS AFTERNOON INTO TONIGHT...WE
FINALLY GET ON THE BACKSIDE OF ALL OF THE PASSING SHORTWAVES IN NW
FLOW...WHICH MEANS WE WILL FINALLY SHUT OFF THE SNOW MACHINES AND
WORK A CLEARING OF THE LOW CLOUDS AT LEAST FROM WEST TO EAST.
FOR TEMPERATURES...BASED ON THE WARMER TEMPERATES SEEN
YESTERDAY...FAVORED HIGHS TODAY TOWARD THE HIGHER END OF
GUIDANCE...ESPECIALLY SOUTH OF THE BOUNDARY. FOR TONIGHT...WINDS
WILL START TO INCREASE OUT OF THE SW AND WILL START TO ADVECT IN A
MILDER PACIFIC AIRMASS. THE WAA WILL BE TEMPERED A BIT BY AT LEAST A
PARTIAL CLEARING OF THE SKIES AND ATTENDANT RADIATIONAL
COOLING...BUT LOOKS TO BE ENOUGH TO SAFELY KEEP EVERYONE ABOVE ZERO
FOR A SECOND NIGHT IN A ROW.
.LONG TERM...(FRIDAY THROUGH WEDNESDAY)
ISSUED AT 348 AM CST THU DEC 26 2013
LONG TERM TRENDS CONTINUE TO REMAIN ON TRACK AT LEAST EARLY IN THE
PERIOD. STILL SEE THE POTENTIAL OF AT LEAST GROUND BLIZZARD
CONDITIONS DEVELOPING BY SATURDAY NIGHT ACROSS MUCH OF WESTERN
INTO SOUTHERN MINNESOTA. STILL RATHER MILD BEFORE THEN.
SHOULD SEE SOME HIGH TEMPERATURES WARMING TO AROUND 40 OR SO IN
SOUTHWEST MINNESOTA ON FRIDAY. VERY MILD PACIFIC AIR RIDES EAST
INTO THE AREA FRIDAY...WITH 85H TEMPERATURES WARMING TO 8-10C BY
FRIDAY EVENING OVER THE SOUTHWEST. MINIMAL MIX WITH THIS SHOULD
YIELD THE WARMER TEMPERATURES...WITH LOWER AND SOME MIDDLE 30S TO
THE EAST. SHOULD REMAIN RATHER WARM FRIDAY NIGHT AHEAD OF THE
ARCTIC FRONT. LOWS WILL BE DETERMINED BY WINDS OVERNIGHT. ANY
DECOUPLING OF THE BL WILL STILL GENERATE SOME COOL READINGS.
OVERALL...MODELS HAVE TRENDED A LITTLE WETTER WITH THE TROUGH ASSOCIATED
WITH THE ARCTIC COLD FRONT THAT WILL DIVE SOUTH OVER THE AREA
SATURDAY NIGHT. IT DOES APPEAR THERE WILL BE THE POTENTIAL OF AT
LEAST A PERIOD OF SNOW ASSOCIATED WITH THIS FEATURE AS IT MOVES
THROUGH. DID USE POTWX AND INTRODUCED SOME FREEZING DRIZZLE AT
LEAST INITIALLY AS THE FRONT ARRIVES. THIS...ALONG WITH SOME OF
THE MORE MILD TEMPERATURES MAY PROHIBIT SIGNIFICANT BLOWING SNOW
DEVELOPMENT FOR A TIME...BUT BELIEVE ANY POTENTIAL CRUST ON THE
SNOW WILL BE ERODED BY THE STRONG WINDS DEVELOPING AS THE COLD AIR
ARRIVES. BUFKIT PROFILES STILL INDICATE WIND GUSTS AROUND 35 KTS PLUS
LIKELY SATURDAY NIGHT...ESPECIALLY ALONG AND SOUTH OF THE
MINNESOTA RIVER VALLEY. THIS SHOULD BE ENOUGH TO GENERATE THE MORE
WIDESPREAD BLOWING SNOW CONDITIONS. WILL HAVE TO MONITOR THIS
TREND WITH HEADLINES A DEFINITE POSSIBILITY.
VERY COLD CONDITIONS ENSUE FOR MONDAY AND TUESDAY. MONDAY MORNING
APPEARS TO BE LIKELY THE COLDEST FOR THE CWA...WITH TUESDAY
MORNING A GOOD SECOND...ESPECIALLY TO THE EAST. MUCH OF THE AREA
MAY STAY BELOW ZERO ON MONDAY. SURFACE WINDS SHOULD BE
LIGHT...BUT MAY STILL PRODUCE WIND CHILLS CLOSE TO WARNING
CRITERIA OVER THE NORTHERN CWA SUNDAY NIGHT/MONDAY MORNING. TIMING
OF ANY ADDITIONAL SNOW EVENTS DIFFICULT...ALTHOUGH THE GFS AND GEM
CONTINUE TO TRACK A SHOT OF LIGHT SNOW OVER SOUTHERN MINNESOTA
MONDAY NIGHT INTO EARLY TUESDAY. HAVE ENTERED A CHANCE FOR SNOW
WITH THIS FOR NOW. SOME MINOR TEMPERATURE MODERATION LATER IN THE
PERIOD COULD YIELD MORE LIGHT SNOW...BUT DIFFICULT TO LATCH ONTO
ANYTHING SIGNIFICANT AT THIS TIME.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z FRIDAY AFTERNOON)
ISSUED AT 1149 AM CST THU DEC 26 2013
SNOW WILL CONTINUE SLIDING SOUTHEAST ACROSS ERN MN AND SWRN MN
EARLY THIS AFTERNOON WITH DRY CONDITIONS THEREAFTER. VSBYS HAVE
IMPROVING WITH THE SNOW AND INTENSITY SHOULD CONTINUE TO WANE IN
THE NEXT COUPLE HOURS. MVFR CIGS LIKELY TO REMAIN INTO THIS
EVENING NORTH OF THE MN RIVER...BUT IMPROVING CONDITIONS EXPECTED
LATE TONIGHT AND ESPECIALLY FRIDAY.
KMSP...SNOW SHOULD END BY 20Z...OTHERWISE CIGS WILL BOUNCE BACK
AND FORTH BETWEEN VFR/MVFR THROUGH THE EVENING /REMAINING ABOVE 017./
VFR RETURNS LATE TONIGHT AND FRIDAY.
/OUTLOOK FOR KMSP/
FRI NIGHT...VFR. WINDS SW 4-8 KTS.
SAT...VFR. CHC MVFR/-SN LATE. LIGHT/VAR WINDS BCMG N 20G30KTS LATE.
SUN...VFR. WINDS NW 10 KTS.
&&
.MPX WATCHES/WARNINGS/ADVISORIES...
MN...NONE.
WI...NONE.
&&
$$
SHORT TERM...MPG
LONG TERM...DWE
AVIATION...BORGHOFF
AREA FORECAST DISCUSSION
NWS TWIN CITIES/CHANHASSEN MN
501 AM CST THU DEC 26 2013
.UPDATE...
12Z AVIATION DISCUSSION ADDED BELOW.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 348 AM CST THU DEC 26 2013
WE CONTINUE TO FIND OURSELVES WITHIN MOIST CYCLONIC NORTHWEST FLOW
THIS MORNING...WITH CLOUDS AND BOUTS OF FLURRIES/LIGHT SNOW
CONTINUING TO DOMINATE THE NRN PLAINS AND UPPER MS VALLEY. THE TWO
FEATURES OF INTEREST THIS MORNING ARE THE STRONG UPPER WAVE
CURRENTLY VISIBLE IN WATER VAPOR IMAGERY MOVING ACROSS THE DAKOTAS
AND A WARM/STATIONARY FRONT THAT IS MORE OR LESS LINED UP WITH THE
MN RIVER FROM WC INTO SE MN. CURRENT THINKING IS THAT THIS FRONT
WILL ACT AS A FOCUS FOR A HEAVIER BAND OF PRECIP FROM ABOUT 15Z-21Z
TODAY. BASED POP/QPF GRIDS FOR THIS BAND OF SNOW ON THE GFS AND
SREF...WHICH RESULTED IN THE BAND COMING DOWN BETWEEN I-94 AND THE
MN RIVER. THOUGH CATEGORICAL POPS HAVE BEEN RETAINED...THE HRRR AND
HOPWRF MEMBERS ALONG THE THE NAM/GEM SHOW VERY LITTLE SNOW COMING
DOWN ALONG THIS FRONT...INSTEAD TAKING MOST OF IT ACROSS NRN MN WITH
THE BRUNT OF THE FORCING WITH THE UPPER WAVE...SO WOULD NOT BE
SURPRISED IF THESE POPS END UP BEING OVERDONE. THIS LOOKS TO BE A
FAIRLY TRANSIENT FEATURE WHICH MEANS IT IS ONLY EXPECTED TO BRING A
DUSTING TO ONE INCH OF SNOW. FOR THIS AFTERNOON INTO TONIGHT...WE
FINALLY GET ON THE BACKSIDE OF ALL OF THE PASSING SHORTWAVES IN NW
FLOW...WHICH MEANS WE WILL FINALLY SHUT OFF THE SNOW MACHINES AND
WORK A CLEARING OF THE LOW CLOUDS AT LEAST FROM WEST TO EAST.
FOR TEMPERATURES...BASED ON THE WARMER TEMPERATES SEEN
YESTERDAY...FAVORED HIGHS TODAY TOWARD THE HIGHER END OF
GUIDANCE...ESPECIALLY SOUTH OF THE BOUNDARY. FOR TONIGHT...WINDS
WILL START TO INCREASE OUT OF THE SW AND WILL START TO ADVECT IN A
MILDER PACIFIC AIRMASS. THE WAA WILL BE TEMPERED A BIT BY AT LEAST A
PARTIAL CLEARING OF THE SKIES AND ATTENDANT RADIATIONAL
COOLING...BUT LOOKS TO BE ENOUGH TO SAFELY KEEP EVERYONE ABOVE ZERO
FOR A SECOND NIGHT IN A ROW.
.LONG TERM...(FRIDAY THROUGH WEDNESDAY)
ISSUED AT 348 AM CST THU DEC 26 2013
LONG TERM TRENDS CONTINUE TO REMAIN ON TRACK AT LEAST EARLY IN THE
PERIOD. STILL SEE THE POTENTIAL OF AT LEAST GROUND BLIZZARD
CONDITIONS DEVELOPING BY SATURDAY NIGHT ACROSS MUCH OF WESTERN
INTO SOUTHERN MINNESOTA. STILL RATHER MILD BEFORE THEN.
SHOULD SEE SOME HIGH TEMPERATURES WARMING TO AROUND 40 OR SO IN
SOUTHWEST MINNESOTA ON FRIDAY. VERY MILD PACIFIC AIR RIDES EAST
INTO THE AREA FRIDAY...WITH 85H TEMPERATURES WARMING TO 8-10C BY
FRIDAY EVENING OVER THE SOUTHWEST. MINIMAL MIX WITH THIS SHOULD
YIELD THE WARMER TEMPERATURES...WITH LOWER AND SOME MIDDLE 30S TO
THE EAST. SHOULD REMAIN RATHER WARM FRIDAY NIGHT AHEAD OF THE
ARCTIC FRONT. LOWS WILL BE DETERMINED BY WINDS OVERNIGHT. ANY
DECOUPLING OF THE BL WILL STILL GENERATE SOME COOL READINGS.
OVERALL...MODELS HAVE TRENDED A LITTLE WETTER WITH THE TROUGH ASSOCIATED
WITH THE ARCTIC COLD FRONT THAT WILL DIVE SOUTH OVER THE AREA
SATURDAY NIGHT. IT DOES APPEAR THERE WILL BE THE POTENTIAL OF AT
LEAST A PERIOD OF SNOW ASSOCIATED WITH THIS FEATURE AS IT MOVES
THROUGH. DID USE POTWX AND INTRODUCED SOME FREEZING DRIZZLE AT
LEAST INITIALLY AS THE FRONT ARRIVES. THIS...ALONG WITH SOME OF
THE MORE MILD TEMPERATURES MAY PROHIBIT SIGNIFICANT BLOWING SNOW
DEVELOPMENT FOR A TIME...BUT BELIEVE ANY POTENTIAL CRUST ON THE
SNOW WILL BE ERODED BY THE STRONG WINDS DEVELOPING AS THE COLD AIR
ARRIVES. BUFKIT PROFILES STILL INDICATE WIND GUSTS AROUND 35 KTS PLUS
LIKELY SATURDAY NIGHT...ESPECIALLY ALONG AND SOUTH OF THE
MINNESOTA RIVER VALLEY. THIS SHOULD BE ENOUGH TO GENERATE THE MORE
WIDESPREAD BLOWING SNOW CONDITIONS. WILL HAVE TO MONITOR THIS
TREND WITH HEADLINES A DEFINITE POSSIBILITY.
VERY COLD CONDITIONS ENSUE FOR MONDAY AND TUESDAY. MONDAY MORNING
APPEARS TO BE LIKELY THE COLDEST FOR THE CWA...WITH TUESDAY
MORNING A GOOD SECOND...ESPECIALLY TO THE EAST. MUCH OF THE AREA
MAY STAY BELOW ZERO ON MONDAY. SURFACE WINDS SHOULD BE
LIGHT...BUT MAY STILL PRODUCE WIND CHILLS CLOSE TO WARNING
CRITERIA OVER THE NORTHERN CWA SUNDAY NIGHT/MONDAY MORNING. TIMING
OF ANY ADDITIONAL SNOW EVENTS DIFFICULT...ALTHOUGH THE GFS AND GEM
CONTINUE TO TRACK A SHOT OF LIGHT SNOW OVER SOUTHERN MINNESOTA
MONDAY NIGHT INTO EARLY TUESDAY. HAVE ENTERED A CHANCE FOR SNOW
WITH THIS FOR NOW. SOME MINOR TEMPERATURE MODERATION LATER IN THE
PERIOD COULD YIELD MORE LIGHT SNOW...BUT DIFFICULT TO LATCH ONTO
ANYTHING SIGNIFICANT AT THIS TIME.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z FRIDAY MORNING)
ISSUED AT 447 AM CST THU DEC 26 2013
WARM FRONT RIGHT NOW IS JUST NE OF THE MN RIVER. BETWEEN THE WARM
FRONT AND I-94...A CLEARING HAS DEVELOPED...WHICH WILL PLACE
AXN/STC/MSP ON THE EDGE OF MVFR CIGS UNTIL ANOTHER LIGHT SNOW
BURST ARRIVES LATER THIS MORNING. NOT MUCH WAS CHANGED WITH
TIMING OF THE SNOW FROM EXISTING TAFS...AS IT MATCHES UP WELL WITH
THE SREF PROBS. EXPECT MVFR/TEMPO IFR VIS SNOW TO MOVE THROUGH MN
TERMINALS...BUT MAY SLIDE SOUTH OF WIS TERMINALS. NOT COMPLETELY
SOLD ON THIS SNOW PANNING OUT AS THE HRRR AND HOPWRF CONTINUE TO
STRUGGLE TO BRING MUCH SNOW DOWN ALONG THE WARM FRONT OVER SRN MN.
BEHIND THE SNOW...WE WILL REMAIN MOIST IN THE LOW LEVELS...SO
EXPECT LOWER CIGS TO HANG AROUND UNTIL THE FRONT BEGINS TO HEAD
EAST IN THE EVENING...BRINGING VFR CIGS IN ITS WAKE.
KMSP...ASSUMING THE SREF IS RIGHT...CONFIDENCE IS HIGH IN CURRENT
SNOW TIMING...BUT SOME OF THE SHORT TERM GUIDANCE SHOWS THE
AIRPORT REMAINING DRY...SO THERE IS THE POTENTIAL WE DON/T SEE
MUCH MORE THAN SOME FLURRIES LATE MORNING. CIG FORECAST WILL BE
TOUGH AS EDGE OF MVFR CIGS WILL LIKELY REMAIN JUST NORTHEAST OF
THE FIELD...AND MAY TRY TO BUILD BACK SOUTH AHEAD OF THE
SNOW...SO WILL HAVE TO WATCH THAT AS WELL. WINDS WILL REMAIN
VARIABLE AND UNDER 7 KTS THROUGH TONIGHT. CONFIDENCE IN CIGS THIS
AFTERNOON IS LOW...AS IT MAY JUST STAY VFR...BUT EVENTUALLY BOTH
THE GFS AND NAM SHOW ATMO BELOW 20K FT DRYING OUT PRETTY GOOD
TONIGHT.
/OUTLOOK FOR KMSP/
FRI...VFR. WINDS SW 5-10 KTS.
SAT...VFR. CHC MVFR/-SN LATE. WINDS SW 5-10 KTS BCMG NW 20G30KTS.
SUN...VFR. WINDS NW 10 KTS.
&&
.MPX WATCHES/WARNINGS/ADVISORIES...
MN...NONE.
WI...NONE.
&&
$$
SHORT TERM...MPG
LONG TERM...DWE
AVIATION...MPG
AREA FORECAST DISCUSSION
NWS TWIN CITIES/CHANHASSEN MN
352 AM CST THU DEC 26 2013
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 348 AM CST THU DEC 26 2013
WE CONTINUE TO FIND OURSELVES WITHIN MOIST CYCLONIC NORTHWEST FLOW
THIS MORNING...WITH CLOUDS AND BOUTS OF FLURRIES/LIGHT SNOW
CONTINUING TO DOMINATE THE NRN PLAINS AND UPPER MS VALLEY. THE TWO
FEATURES OF INTEREST THIS MORNING ARE THE STRONG UPPER WAVE
CURRENTLY VISIBLE IN WATER VAPOR IMAGERY MOVING ACROSS THE DAKOTAS
AND A WARM/STATIONARY FRONT THAT IS MORE OR LESS LINED UP WITH THE
MN RIVER FROM WC INTO SE MN. CURRENT THINKING IS THAT THIS FRONT
WILL ACT AS A FOCUS FOR A HEAVIER BAND OF PRECIP FROM ABOUT 15Z-21Z
TODAY. BASED POP/QPF GRIDS FOR THIS BAND OF SNOW ON THE GFS AND
SREF...WHICH RESULTED IN THE BAND COMING DOWN BETWEEN I-94 AND THE
MN RIVER. THOUGH CATEGORICAL POPS HAVE BEEN RETAINED...THE HRRR AND
HOPWRF MEMBERS ALONG THE THE NAM/GEM SHOW VERY LITTLE SNOW COMING
DOWN ALONG THIS FRONT...INSTEAD TAKING MOST OF IT ACROSS NRN MN WITH
THE BRUNT OF THE FORCING WITH THE UPPER WAVE...SO WOULD NOT BE
SURPRISED IF THESE POPS END UP BEING OVERDONE. THIS LOOKS TO BE A
FAIRLY TRANSIENT FEATURE WHICH MEANS IT IS ONLY EXPECTED TO BRING A
DUSTING TO ONE INCH OF SNOW. FOR THIS AFTERNOON INTO TONIGHT...WE
FINALLY GET ON THE BACKSIDE OF ALL OF THE PASSING SHORTWAVES IN NW
FLOW...WHICH MEANS WE WILL FINALLY SHUT OFF THE SNOW MACHINES AND
WORK A CLEARING OF THE LOW CLOUDS AT LEAST FROM WEST TO EAST.
FOR TEMPERATURES...BASED ON THE WARMER TEMPERATES SEEN
YESTERDAY...FAVORED HIGHS TODAY TOWARD THE HIGHER END OF
GUIDANCE...ESPECIALLY SOUTH OF THE BOUNDARY. FOR TONIGHT...WINDS
WILL START TO INCREASE OUT OF THE SW AND WILL START TO ADVECT IN A
MILDER PACIFIC AIRMASS. THE WAA WILL BE TEMPERED A BIT BY AT LEAST A
PARTIAL CLEARING OF THE SKIES AND ATTENDANT RADIATIONAL
COOLING...BUT LOOKS TO BE ENOUGH TO SAFELY KEEP EVERYONE ABOVE ZERO
FOR A SECOND NIGHT IN A ROW.
.LONG TERM...(FRIDAY THROUGH WEDNESDAY)
ISSUED AT 348 AM CST THU DEC 26 2013
LONG TERM TRENDS CONTINUE TO REMAIN ON TRACK AT LEAST EARLY IN THE
PERIOD. STILL SEE THE POTENTIAL OF AT LEAST GROUND BLIZZARD
CONDITIONS DEVELOPING BY SATURDAY NIGHT ACROSS MUCH OF WESTERN
INTO SOUTHERN MINNESOTA. STILL RATHER MILD BEFORE THEN.
SHOULD SEE SOME HIGH TEMPERATURES WARMING TO AROUND 40 OR SO IN
SOUTHWEST MINNESOTA ON FRIDAY. VERY MILD PACIFIC AIR RIDES EAST
INTO THE AREA FRIDAY...WITH 85H TEMPERATURES WARMING TO 8-10C BY
FRIDAY EVENING OVER THE SOUTHWEST. MINIMAL MIX WITH THIS SHOULD
YIELD THE WARMER TEMPERATURES...WITH LOWER AND SOME MIDDLE 30S TO
THE EAST. SHOULD REMAIN RATHER WARM FRIDAY NIGHT AHEAD OF THE
ARCTIC FRONT. LOWS WILL BE DETERMINED BY WINDS OVERNIGHT. ANY
DECOUPLING OF THE BL WILL STILL GENERATE SOME COOL READINGS.
OVERALL...MODELS HAVE TRENDED A LITTLE WETTER WITH THE TROUGH ASSOCIATED
WITH THE ARCTIC COLD FRONT THAT WILL DIVE SOUTH OVER THE AREA
SATURDAY NIGHT. IT DOES APPEAR THERE WILL BE THE POTENTIAL OF AT
LEAST A PERIOD OF SNOW ASSOCIATED WITH THIS FEATURE AS IT MOVES
THROUGH. DID USE POTWX AND INTRODUCED SOME FREEZING DRIZZLE AT
LEAST INTIALLY AS THE FRONT ARRIVES. THIS...ALONG WITH SOME OF
THE MORE MILD TEMPERATURES MAY PROHIBIT SIGNIFICANT BLOWING SNOW
DEVELOPMENT FOR A TIME...BUT BELIEVE ANY POTENTIAL CRUST ON THE
SNOW WILL BE ERODED BY THE STRONG WINDS DEVELOPING AS THE COLD AIR
ARRIVES. BUFKIT PROFILES STILL INDICATE WIND GUSTS AROUND 35 KTS PLUS
LIKELY SATURDAY NIGHT...ESPECIALLY ALONG AND SOUTH OF THE
MINNESOTA RIVER VALLEY. THIS SHOULD BE ENOUGH TO GENERATE THE MORE
WIDESPREAD BLOWING SNOW CONDITIONS. WILL HAVE TO MONITOR THIS
TREND WITH HEADLINES A DEFINITE POSSIBILITY.
VERY COLD CONDITIONS ENSUE FOR MONDAY AND TUESDAY. MONDAY MORNING
APPEARS TO BE LIKELY THE COLDEST FOR THE CWA...WITH TUESDAY
MORNING A GOOD SECOND...ESPECIALLY TO THE EAST. MUCH OF THE AREA
MAY STAY BELOW ZERO ON MONDAY. SURFACE WINDS SHOULD BE
LIGHT...BUT MAY STILL PRODUCE WIND CHILLS CLOSE TO WARNING
CRITERIA OVER THE NORTHERN CWA SUNDAY NIGHT/MONDAY MORNING. TIMING
OF ANY ADDITIONAL SNOW EVENTS DIFFICULT...ALTHOUGH THE GFS AND GEM
CONTINUE TO TRACK A SHOT OF LIGHT SNOW OVER SOUTHERN MINNESOTA
MONDAY NIGHT INTO EARLY TUESDAY. HAVE ENTERED A CHANCE FOR SNOW
WITH THIS FOR NOW. SOME MINOR TEMPERATURE MODERATION LATER IN THE
PERIOD COULD YIELD MORE LIGHT SNOW...BUT DIFFICULT TO LATCH ONTO
ANYTHING SIGNIFICANT AT THIS TIME.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z THURSDAY NIGHT)
ISSUED AT 1050 PM CST WED DEC 25 2013
A 2000-3000FT DECK WILL CONTINUE TO EXPAND EAST/SOUTHEAST ACROSS
THE TAF AREA OVERNIGHT. EXPECT A FEW ATTENDANT LIGHT SNOW SHOWERS
AND/OR FLURRIES...BUT THE MAIN BAND OF VSBY-REDUCING SNOW WILL
MOVE ACROSS THE AREA AFTER DAYBREAK THURSDAY. THE PRIMARY WINDOW
FOR 1-3SM VSBY REDUCTIONS AND SNOW WILL PRIMARILY EXIST BETWEEN
13Z AND 21Z. AFTER THE SNOW ENDS...A SCT-BKN MVFR DECK WILL LINGER
THROUGH 00Z FRIDAY...WITH SCATTERING EXPECTED FROM WEST TO EAST ON
THURSDAY NIGHT. LIGHT/VARIABLE TO SOUTHEAST WINDS AT 5-8KTS
EXPECTED FOR THURSDAY.
KMSP...
MVFR DECK WILL PREVAIL OVERNIGHT...WITH FLURRIES AND/OR VERY LIGHT
SNOW POSSIBLE. A MORE ORGANIZED AREA OF SNOW WILL ARRIVE AROUND
16Z...WITH 1-3SM VSBYS EXPECTED THROUGH 21Z...WITH TOTAL ACCUM
AROUND OR JUST ABOVE ONE INCH EXPECTED. MVFR LEVEL CLOUDS LINGER
THURSDAY AFTERNOON...WITH BREAKS MORE COMMON AFTER 00Z FRIDAY.
/OUTLOOK FOR KMSP/
FRI...VFR. WINDS SW 5-10 KTS.
SAT...VFR. CHC MVFR/-SN LATE. WINDS SW 5-10 KTS BCMG NW 20G30KTS.
SUN...VFR. WINDS NW 10 KTS.
&&
.MPX WATCHES/WARNINGS/ADVISORIES...
MN...NONE.
WI...NONE.
&&
$$
SHORT TERM...MPG
LONG TERM...DWE
AVIATION...LS
AREA FORECAST DISCUSSION
NWS HASTINGS NE
1215 PM CST THU DEC 26 2013
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 500 AM CST THU DEC 26 2013
WITH A CONTINUED EFFECTIVELY ZERO RISK OF PRECIP DURING THE NEXT
24 HOURS...TEMPS/SKY COVER/WIND SPEEDS REMAIN THE MAIN ISSUES. AS
DESCRIBED IN DETAIL BELOW...BOTH WIND SPEEDS AND ESPECIALLY TEMPS
HAVE BEEN BUMPED UP FOR TODAY...WITH THE MAIN WILD CARD FACTOR
BEING THE EXTENT/DURATION OF INCOMING MID-HIGH LEVEL CLOUDS.
ALTHOUGH MODELS SUCH AS THE NAM AND TO A MUCH LESSER EXTENT THE
RAP CONTINUE TO STRUGGLE WITH POORLY INITIALIZED/OVERDONE SNOW
COVER FIELDS...THE VERY LATEST 06Z NAM HAS FINALLY STARTED
LATCHING ONTO REALITY AND HOPEFULLY HELPS PAVE THE WAY FOR MORE
STRAIGHTFORWARD TEMP FORECASTING OVER THE NEXT FEW DAYS.
STARTING OFF EARLY THIS MORNING AS OF 0930Z THE LATEST 11-3.9
MICRON SATELLITE LOOP REVEALED PREDOMINANTLY CLEAR SKIES OVER THE
CWA...ALTHOUGH A FAIRLY DECENT BATCH OF MID-HIGH CLOUDS WAS
STEADILY APPROACHING THE AREA FROM SD. WATER VAPOR SATELLITE
IMAGERY AND SHORT TERM MODEL DATA DEPICTED CONTINUED NORTHWEST
MID-UPPER LEVEL FLOW OVER THE CENTRAL PLAINS...FLOWING BETWEEN A
LARGE SCALE TROUGH OVER THE EASTERN CONUS AND AN EXPANSIVE RIDGE
CENTERED ALONG/WEST OF THE PACIFIC COAST. ON THE SMALLER SCALE...A
FAIRLY SUBTLE DISTURBANCE WAS MAKING ITS WAY SOUTH-SOUTHEAST
ACROSS THE DAKOTAS AND IS LARGELY RESPONSIBLE FOR THE INCOMING
CLOUDS...WITH THIS FEATURE LOCATED WITHIN THE LEFT EXIT REGION OF
THE LATEST IN A SERIES OF 110+KT UPPER JET STREAKS POKING
SOUTHWARD INTO THE NORTHERN ROCKIES OUT OF SOUTHWESTERN CANADA. AT
THE SURFACE...09Z OBJECTIVE ANALYSIS AND AREA AUTOMATED OBS
REVEALED THE PRESENCE OF A SUBTLE NORTH-SOUTH TROUGH AXIS ACROSS
THE CWA...EXTENDING SOUTHWARD FROM A 1014 MILLIBAR LOW CENTERED
NEAR THE BORDER OF ND/SASKATCHEWAN/MANITOBA. MEANWHILE TO THE
SOUTH...A BROAD 1031MB HIGH WAS CENTERED OVER THE OK/WEST TX AREA.
THE NET RESULT OF THESE FEATURES IS A GENERALLY SOUTHWESTERLY
BREEZE OF 5-10 MPH ACROSS MOST OF THE CWA WITH SOME HIGHER GUSTS.
AS IS TYPICAL...THERE HAS BEEN AN EBB AND FLOW OF TEMPS OVERNIGHT
ACROSS THE CWA...AS THE FACTORS OF CLEAR SKIES AND LOCALIZED VERY
LIGHT BREEZES HAVE ALLOWED SOME PLACES TO FALL FAIRLY
EFFICIENTLY...WHILE OTHER PLACES INCLUDING THE TRI-CITIES HAVE
BEEN HELD UP FAIRLY WELL BY THE WESTERLY BREEZES. ALTHOUGH THESE
FLUCTUATIONS WILL CONTINUE THROUGH DAYBREAK...THE GENERAL
EXPECTATION IS THAT OVERNIGHT LOW TEMPERATURES ACROSS THE MAJORITY
OF THE CWA HAVE SETTLED/WILL SETTLE SOMEWHERE INTO THE 17-24 RANGE.
GETTING INTO THE DAYTIME FORECAST...THE BIG PICTURE ALOFT IN THE
MID-UPPER LEVELS INVOLVES THE CONTINUATION OF VERY SUBTLE HEIGHT
RISES AS EVIDENT AT 500MB...AS THE DISTURBANCE CURRENTLY CENTERED
OVER THE DAKOTAS TRACKS SOUTHEAST OVER MAINLY EASTERN PORTIONS OF
THE LOCAL AREA...BUT ESPECIALLY INTO THE IA/MN AREA...ALLOWING THE
WESTERN RIDGE TO NUDGE EVER SO SLIGHTLY EAST INTO THE CENTRAL PLAINS.
AS THIS OCCURS...THE TRAILING NORTH-SOUTH ORIENTED UPPER JET
STREAK WILL ALSO SLIDE EAST FROM THE NORTHERN ROCKIES INTO THE
DAKOTAS OVER THE COURSE OF THE DAY. AT THE SURFACE TODAY...THERE
WILL BE A SIMILAR SCENARIO TO WHAT OCCURRED YESTERDAY...AS
INITIALLY SOUTHWESTERLY BREEZES WILL SWITCH TO NORTHWESTERLY IN
RESPONSE TO THE EASTWARD PROGRESSION OF THE PARENT SURFACE TROUGH
CENTERED TO THE NORTH. AS MIXING HEIGHTS INCREASE TO THE 900-875MB
RANGE PER RAP SOUNDINGS...WIND SPEEDS WILL PICK UP WITH SUSTAINED
NORTHWESTERLY SPEEDS OF 15-20 MPH AND GUSTS UP TO AROUND 25
MPH...WITH THE MAIN TIME FRAME OF STRONGEST BREEZES CENTERED
BETWEEN LATE MORNING AND MID-AFTERNOON BEFORE SUBSIDING AGAIN
LATER IN THE AFTERNOON. THESE WIND SPEEDS REFLECT ROUGHLY A 5 MPH
INCREASE VERSUS PREVIOUS FORECAST FOR MUCH OF THE AREA. TURNING TO
SKY COVER...THIS IS A BIT OF A QUESTION MARK TODAY AS MODELS ARE
HANDLING THE INCOMING CLOUD DECK SOMEWHAT DIFFERENTLY. THE GENERAL
EXPECTATION THOUGH IS THAT ALTHOUGH ESPECIALLY NORTHERN PARTS OF
THE AREA COULD GO MOSTLY CLOUDY FOR A TIME THIS MORNING...THE
OVERALL DENSITY OF THIS CLOUD DECK SHOULD FADE WITH TIME AND WITH
SOUTHWARD EXTENT...RESULTING IN NO WORSE THAN PARTLY CLOUDY IF NOT
MOSTLY SUNNY CONDITIONS THROUGH THE BALANCE OF THE DAY. PUT
ANOTHER WAY...THE CURRENT SKY COVER GRIDS MAY NOT BE QUITE
AGGRESSIVE ENOUGH FOR LATER THIS MORNING...BUT THINK THAT THE DAY
OVERALL WILL FEATURE MORE SUN THAN CLOUDS. AS FOR TEMPS TODAY...FOR
NOW WILL ASSUME A RATHER NEGLIGIBLE EFFECT OF PASSING CLOUD
COVER...AND THUS GIVEN THE DECENT LOW LEVEL MIXING REGIME IN
PLACE...HAVE BOOSTED HIGH TEMPS AT LEAST A FEW DEGREES VERSUS
PREVIOUS FORECAST ACROSS THE NORTHERN HALF OF THE CWA...AND AS
MUCH AS 5-9 DEGREES IN THE SOUTH. BASED ON WHAT HAPPENED
YESTERDAY...NEARLY ALL PRIMARY MODELS/GUIDANCE FELL AT LEAST
SLIGHTLY SHORT OF ACTUAL HIGHS...BUT HOURLY RAP13 TEMPS ENDED UP
BEING ONE OF THE BEST SOLUTIONS. AS A RESULT...HAVE AGAIN OPTED TO
FOLLOW RAP13 TEMPS QUITE CLOSELY TODAY...WHICH RESULTS IN HIGHS
GENERALLY 4-7 DEGREE WARMER THAN A SIMPLE BLEND OF 00Z MET/MAV
GUIDANCE. THE NET RESULT IS HIGH TEMPERATURES AIMED FROM THE UPPER
40S/LOW 50S IN THE NORTHERN 1/2 OF THE CWA TO PREDOMINANTLY MID-
50S IN KS ZONES. IF ANYTHING...MIGHT NOT HAVE GONE WARM ENOUGH IN
NORTHEAST ZONES. THIS INCREASE IN HIGH TEMPS RESULTS IN AFTERNOON
RELATIVE HUMIDITY VALUES FORECAST TO DROP AROUND 25 PERCENT OR
SLIGHTLY LOWER IN SOUTHWESTERN COUNTIES...BUT GIVEN THAT SUSTAINED
WINDS SHOULD AVERAGE CLOSER TO 15 MPH THAN 20 MPH IN THESE
AREAS...THE SETUP APPEARS TO FALL A BIT SHORT OF JUSTIFYING A
NEAR-CRITICAL FIRE DANGER MENTION IN THE HAZARDOUS WEATHER
OUTLOOK.
TURNING TO THIS EVENING/TONIGHT...THE LARGE SCALE SYNOPTIC PICTURE
INVOLVES THE CONTINUED EXPANSION OF THE WESTERN CONUS RIDGE
EASTWARD OVER THE CENTRAL PLAINS...ACCOMPANIED BY RESULTANT MID-
LEVEL HEIGHT RISES. ALTHOUGH THE PRIMARY UPPER JET CORE WILL
CONTINUE TO SLIDE OFF TO THE NORTH-NORTHEAST OF THE AREA...THE
CONTINUED NORTH-NORTHWESTERLY FLOW ALOFT OVER THE CENTRAL PLAINS
WILL NONETHELESS FEATURE THE PASSAGE OF AT LEAST ONE SUBTLE...LOW-
AMPLITUDE SHORTWAVE TROUGH DURING THE NIGHT. ALTHOUGH THIS COULD
EASILY RESULT IN A MODEST INCREASE IN MID-HIGH LEVEL CLOUDS MAINLY
AFTER MIDNIGHT AND MAINLY IN NORTHERN ZONES...THE NIGHT AS A WHOLE
SHOULD AVERAGE NO WORSE THAN MOSTLY CLEAR ACROSS THE ENTIRE CWA.
AT THE SURFACE TONIGHT...A NOW-FAMILIAR PATTERN WILL AGAIN REPEAT
ITSELF...AS A SUBTLE TROUGH AXIS WILL AGAIN EXTEND SOUTHWARD INTO
THE CENTRAL PLAINS FROM A PARENT LOW PRESSURE SYSTEM CENTERED WELL
TO THE NORTH OVER SOUTH CENTRAL CANADA. THIS WILL AGAIN TRANSITION
THE NORTHWESTERLY BREEZES OF THIS AFTERNOON TO FAIRLY LIGHT
WESTERLY BREEZES THIS EVENING...AND THEN 5-10 MPH SOUTHWESTERLY
BREEZES AFTER MIDNIGHT. WITH THE SKY COVER...WIND SPEED/DIRECTION
AND LOW LEVEL THERMAL PROFILES TONIGHT SETTING UP TO BE QUITE
SIMILAR TO THOSE OF THIS MORNING...SEE NO REASON WHY TEMPERATURE
BEHAVIOR WON/T BE SIMILAR AS WELL...WITH PLENTY OF HOUR-TO-HOUR
AND SMALL-SCALE VARIABILITY. ALTHOUGH VERY LITTLE CHANGE WAS MADE
TO LOWS FROM THE PREVIOUS FORECAST...STILL CALLING FOR NEARLY THE
ENTIRE CWA TO SETTLE WITHIN A FEW DEGREES EITHER SIDE OF 20 AT
SOME POINT IN THE NIGHT...THIS IS STILL A FEW DEGREES ABOVE A
STRAIGHT-UP 00Z MET/MAV GUIDANCE BLEND...AND WOULD NOT BE
SURPRISED IF THE NEXT SHIFT CONSIDERS RAISING LOWS A BIT MORE IN
SOME PLACES.
.LONG TERM...(FRIDAY THROUGH WEDNESDAY)
ISSUED AT 500 AM CST THU DEC 26 2013
THE BIGGEST CHALLENGE WILL BE DETERMINING THE TIMING OF A COLD FRONT
SATURDAY...WHICH WILL SUBSEQUENTLY AFFECT HIGH TEMPERATURES ON
SATURDAY AND WIND SPEEDS SATURDAY/SATURDAY NIGHT.
WE BEGIN THE LONG TERM FORECAST IN A TRANSITION OF SORTS. THE RIDGE
OVER THE WESTERN UNITED STATES WILL DEAMPLIFY AS IT MOVES
EAST...BEING BROKEN DOWN BY AN APPROACHING SHORTWAVE TROUGH ENTERING
THE COAST OF THE PACIFIC NORTHWEST BY LATE DAY FRIDAY. WE WILL
CLEARLY BE IN THE WARM SECTOR WITH HIGHS EASILY REACHING THE 50S FOR
MOST LOCATIONS IF NOT 60 FOR MUCH OF NORTH CENTRAL KANSAS. MODEL
OUTPUT IS NOT OPTIMAL FOR MAXIMUM TEMPERATURE FORECASTS AS A PHANTOM
SNOWPACK LINGERS OVER MUCH OF THE AREA AND IS DISTURBING THE MODEL
SOLUTIONS...ESPECIALLY FOR MAX T AND WIND FIELDS. REALLY HAD TO LEAN
ON ENSEMBLE DATA AND OPERATIONAL MODELS SUCH AS THE ECMWF THAT
EITHER DO NOT INCLUDE SNOWPACK...OR HAVE LIMITED SNOWPACK DATA
ENTERED INTO MODEL INITIALIZATIONS. THE NAM...SPECIFICALLY...IS
ATROCIOUS AND HAS AFFECTED OTHER SOLUTIONS SUCH AS
CONSRAW...BCCONSRAW...CONSALL...ETC. THIS HAS RENDERED MUCH OF THESE
DATA RATHER USELESS FOR MAXIMUM TEMPERATURE AND WIND FIELDS.
I WENT CLOSER TO CONSRAW OUTPUT FOR MINIMUM TEMPERATURES FRIDAY
NIGHT AS THIS OUTPUT SEEMED TO BE LARGELY UNAFFECTED BY THE
ERRONEOUS SNOWPACK AND THIS OUTPUT TENDS TO DO BEST FOR LOW
TEMPERATURES FOR THE LAST NIGHT BEFORE A COLD FRONT PASSAGE. THE
SREF ADVERTISES QUITE A BIT OF FOG FOR FRIDAY NIGHT...ESPECIALLY IN
OUR EAST...BUT WITH A SOUTHWEST WIND THAT WILL NOT BE PARTICULARLY
LIGHT...I AM DISCOUNTING THIS ADVERTISEMENT.
SATURDAY WILL BE TRICKY AS THE AFOREMENTIONED TROUGH TO THE NORTHWEST
SWEEPS RATHER QUICKLY INTO THE PLAINS...JOINING WITH ANOTHER TROUGH
SWINGING DOWN FROM CANADA TO REINFORCE A SIGNIFICANT SHOT OF MUCH
COLDER AIR. THE TRICKY PART WILL BE TIMING THE ASSOCIATED COLD
FRONT. MODEL SOLUTIONS GENERALLY CONCUR THAT MOST OF THE CWA SHOULD
BE ABLE TO GET IN ONE MORE DAY OF GOOD WARM AIR ADVECTION AHEAD OF
THE COLD FRONT BEFORE IT COMES IN. THE FAR WESTERN AND NORTHERN CWA
ARE MOST AT RISK OF NOT REALIZING TEMPERATURES AS WARM OR WARMER
THAN WHAT OCCURRED ON FRIDAY. I INCREASED TEMPERATURES FOR MOST OF
THE CWA FROM THE PREVIOUS FORECAST...BUT KEPT TEMPERATURES IN THE FAR
WESTERN/NORTHWESTER CWA RATHER SIMILAR AS MEDIUM RANGE MODELS
INDICATE THAT THE COLD FRONT SHOULD MAKE ITS WAY JUST INTO THE CWA
BY NOON SATURDAY. HOWEVER...THE FORECAST FOR MID 50S FOR SATURDAY
COULD CRASH AND BURN RATHER EASILY IF THE COLD AIR COMES IN
FASTER...SO THE CONFIDENCE FOR HIGH TEMPERATURES...ESPECIALLY FROM
THE TRI-CITIES AND FARTHER NORTHWEST...IS NOT AS HIGH AS IT COULD
BE...ESPECIALLY WITH THE POOR MODEL OUTPUT AS OF LATE. HEIGHT RISES
ARE IMPRESSIVE ALONG WITH COLD AIR ADVECTION BEHIND THE COLD
FRONT...ALTHOUGH THESE VARIABLES REALLY TAKE HOLD LATER INTO SATURDAY
NIGHT. I RAISED WIND SPEEDS SIGNIFICANTLY FROM THE PREVIOUS FORECAST
BECAUSE OF THIS...AND WE SHOULD BE IN THE REALM OF WIND ADVISORY AS
FAR SOUTH AS THE TRI-CITIES...AND NOT TOO FAR FROM WIND ADVISORY
FARTHER SOUTH IN OUR CWA FOR SATURDAY NIGHT. THIS CONTINUES TO LOOK
LIKE A DRY FORECAST WITH THE PASSING OF THE COLD FRONT AS THE
MOISTURE PROFILE IS QUITE DRY...ALTHOUGH THERE COULD CERTAINLY BE
SOME STRATUS FOR AWHILE DUE TO THE STRONG COLD AIR ADVECTION AND A
FLURRY IS NOT COMPLETELY OUT OF THE QUESTION. ALTHOUGH MID-LEVELS
ARE QUITE DRY...ANY SATURATION WILL OCCUR AT TEMPERATURES FAR TOO
COLD TO SUPPORT FREEZING DRIZZLE. THE COMBINATION OF THE STRATUS AND
WIND SHOULD KEEP TEMPERATURES FROM BOTTOMING OUT TOO MUCH AND THE
TEMPERATURES FROM THE PREVIOUS FORECAST LOOK PERFECTLY REASONABLE.
JUDGING BY WHAT HAPPENED WITH THE LAST COLD SNAP...I SUSPECT THAT
MODELS ARE GOING TO WANT TO SCOOT THE COLD AIR TO THE EAST TOO
QUICKLY AS THE DEVELOPING UPPER LEVEL RIDGE TO THE WEST TRIES TO
BUILD EAST. THIS IS CONFIRMED BY ENSEMBLE TRENDS FROM THE ECMWF AND
THE GFS. I WENT COLDER THAN THE INITIALIZED ALLBLEND AND PREVIOUS
FORECASTS...ESPECIALLY FOR HIGHS SUNDAY AND MONDAY...AND ALSO LOWS
FOR SUNDAY NIGHT/MONDAY MORNING. THE CENTER OF THE SURFACE HIGH
SHOULD MAKE ITS WAY ACROSS THE CWA SUNDAY NIGHT/MONDAY MORNING TO
ALLOW WINDS TO DROP SIGNIFICANTLY. UNDER CLEAR/MOSTLY CLEAR SKIES
AND WIND BECOMING VERY LIGHT OR CALM NEAR THE CENTER OF THE SURFACE
HIGH...THIS SHOULD ALLOW TEMPERATURES TO REALLY TANK INTO THE SINGLE
DIGITS...AND THEY COULD TANK RELATIVELY EARLY IN THE
NIGHT...DEPENDING ON THE TIMING OF THE SURFACE HIGH.
ONE MORE THING OF NOTE...I STUCK IN A SLIGHT CHANCE OF SNOW IN THE
NORTHEASTERN CWA FOR WEDNESDAY FROM AN IMPULSE WITHIN NORTHWEST
FLOW. TIMING AND POSITIONING ARE DICEY...SO CHANCES OF PRECIPITATION
ARE NOT HIGH IN THE FORECAST. SINCE MORE THAN ONE MODEL SOLUTION
ADVERTISES A SHORTWAVE TROUGH MOVING IN AT ROUGHLY THIS TIME...IT IS
PRUDENT TO INTRODUCE THIS TO THE LONG TERM FORECAST.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z FRIDAY AFTERNOON)
ISSUED AT 1203 PM CST THU DEC 26 2013
VFR CEILINGS AND VISIBILITY WILL CONTINUE THROUGHOUT THE TAF VALID
PERIOD. WILL SEE THE WIND LIGHTEN AND BACK FROM NORTHWEST TO THE
SOUTHWEST THIS EVENING...WHICH IS A TYPICAL DIURNAL RESPONSE TO THE
LOSS OF DIURNAL HEATING. THERE COULD BE A FEW HIGH CLOUDS MOVING
IN TOMORROW MORNING.
&&
.GID WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
KS...NONE.
&&
$$
SHORT TERM...PFANNKUCH
LONG TERM...HEINLEIN
AVIATION...WESELY
AREA FORECAST DISCUSSION
NWS NORTH PLATTE NE
659 AM CST THU DEC 26 2013
.SYNOPSIS...
ISSUED AT 343 AM CST THU DEC 26 2013
NEXT IN THE SERIES OF UPPER PV ANOMALIES...CURRENTLY LOCATED OVER
ERN MT...WILL DROP ACROSS THE NORTHERN PLAINS TODAY...ORIGINATING
FROM THE NORTHERN PACIFIC REGION INSTEAD OF THE ARCTIC. AHEAD OF THE
FEATURES WESTERLY OR SOUTHWESTERLY COMPONENT TO THE WINDS JUST OFF
THE SURFACE IS BRINGING WARMER AIR TO THE WESTERN HIGH PLAINS AND
CONTINUING INTO THE MORNING HOURS. AT THE HEMISPHERIC SCALE...A
PROGRESSIVE PATTERN REMAINS ACROSS THE NORTHERN HEMISPHERE WITH AN
UPPER LOW MOVING QUICKLY INTO THE ERN U.S. AND HIGH PRESSURE ALOFT
BUILDING INTO THE PAC NW.
&&
.UPDATE...
ISSUED AT 659 AM CST THU DEC 26 2013
UPDATED MAX TEMPS FOR THIS AFTERNOON BASED ON EARLY MORNING DATA
RECEIVED FROM THE KLBF RADIOSONDE. TEMPS JUST OFF THE SURFACE
WARMER THAN 26.00 MODELS ANTICIPATED AND WHEN MIXED UNDER FULL SUN
WOULD SUPPORT UPPER 50S FOR SOUTHWEST NEB. HOWEVER...STILL HAVE
MID AND UPPER LEVEL CLOUDS TO CONTENT WITH WHICH WILL LIMIT
HEATING POTENTIAL FOR A PORTION OF THE DAY. HAVE TAKEN A MIDDLE
GROUND FROM WHERE MAX TEMPS WERE IN THE PREV FCST TO MAX POTENTIAL AS
A COMPROMISE. REMAINDER OF THE FORECAST PRETTY MUCH LEFT AS IT WAS.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 343 AM CST THU DEC 26 2013
PREVIOUSLY MENTIONED PV ANOMALY DIVES SOUTHEAST ACROSS THE NORTHERN
PLAINS WHICH WILL DRIVE A WEAK COLD FRONT ACROSS THE AREA LATER IN
THE DAY. BRIEF WARM AIR ADVECTION THIS MORNING WILL ALLOW TEMPS TO
BE WARMER THAN YESTERDAY AND ALTHOUGH WINDS WILL BECOME NWRLY BY
AFTERNOON...COOLER AIR LAGS THE WEAK FRONT SOMEWHAT AND IS WEAK
ESPECIALLY IN THE WEST. IN ADDITION...JET DYNAMICS ARE NOT FAVORABLE
FOR LARGE SCALE ASCENT AND DRIER AIR IN THE MID LEVELS ACCOMPANYING
THE WARMER AIR AHEAD OF THE SYSTEM WOULD PRECLUDE ANY PRECIP
DEVELOPMENT ANYWAY. RESULT IS SOME MID AND HIGH CLOUDS BY LATE
MORNING INTO THE AFTERNOON...COVERAGE SHOULD NOT LIMIT MAX TEMPS
FROM REACHING LEVELS 10 TO 12 DEGREES ABOVE AVERAGE IN THE
SOUTH...BUT ONLY A FEW DEGREES ABOVE AVE IN THE NORTH. STILL SOME
SNOW COVER ACROSS SHERIDAN AND WESTERN CHERRY COUNTIES SO SOME
INFLUENCE ON TEMPS THERE...BUT OTHERWISE MAINLY OPEN GROUND. NAM
TEMPS ARE HEAVILY INFLUENCED STILL BY HAVING TOO MUCH SNOW COVER
ANALYZED.
UPPER RIDGE BUILD ACROSS THE WEST OVER NIGHT WITH GOOD SUBSIDENCE
CLEARING CLOUDS. WILL ALLOW FOR GOOD RADIATIONAL COOLING BUT LOW
TEMPS STILL ABOVE AVE FOR THIS TIME OF YEAR.
.LONG TERM...(FRIDAY THROUGH WEDNESDAY)
ISSUED AT 343 AM CST THU DEC 26 2013
FORECAST FOCUS FOR FRIDAY INTO SATURDAY IS TEMPERATURES. THE THERMAL
RIDGE ALOFT KEEPS TEMPERATURES ABNORMALLY WARM...WITH 850MB
TEMPERATURES AT 9C TO 11C FRIDAY AND FRIDAY NIGHT. MODELS
/ESPECIALLY THE NAM/ ARE HAVING SOME ISSUES WITH THE SNOW
COVER...AND THUS THE AMOUNT OF MIXING/WARMING THAT WILL BE REALIZED
ON FRIDAY. THERE MAY BE SOME HIGH CLOUDS BUT NOT EXPECTING ENOUGH TO
MAKE A HUGE IMPACT ON HIGHS. WILL ALSO HAVE BREEZY WESTERLY WINDS TO
ENHANCE THE DOWNSLOPE WARMING EFFECT...AND HELP WARM TEMPERATURES TO
THE UPPER 40S AND 50S. LOWS FRIDAY NIGHT SHOULD STAY FAIRLY MILD AS
THE WINDS STAY UP AND CLOUDS INCREASE DUE TO AN INCOMING FRONTAL
BOUNDARY.
AN UPPER LEVEL TROUGH WILL PASS ACROSS THE PLAINS SATURDAY NIGHT
INTO SUNDAY. MODEL SOLUTIONS ARE IN GOOD AGREEMENT THAT IMPACT
LOCALLY WILL BE MINIMAL...WITH THE PRIMARY CONCERNS BEING A CHANGE
IN TEMPERATURES.
THERE ARE TWO PRIMARY PV ANOMALIES THAT WILL MOVE THROUGH THE
TROUGH...THE FIRST ORIGINATES OVER THE YUKON AND NORTHWEST
TERRITORIES WHICH THEN DIGS SOUTHWARD AND MOVES THROUGH THE DAKOTAS
ON SUNDAY. THE SECOND IS THE SYSTEM CURRENTLY OUT OVER THE NORTHERN
PACIFIC WHICH WILL MOVE EAST AND DAMPEN THE RIDGE AND MOVE INTO THE
PACIFIC NORTHWEST FRIDAY THEN PROGRESS THROUGH THE TROUGH WITH THE
MAIN PART OF THE PV ANOMALY STAYING WELL SOUTH OF THE FORECAST
AREA...THROUGH THE FOUR CORNERS AND INTO THE SOUTHERN PLAINS. THESE
TWO BITS OF ENERGY WILL NOT PHASE TOGETHER SO UPWARD FORCING WILL
NOT BE GREAT IN THE LOCAL AREA AS THESE SYSTEMS PASS. DID KEEP LOW
CHANCES ACROSS NORTHERN NEBRASKA INTO THE PANHANDLE ON SATURDAY
AFTERNOON AND SATURDAY NIGHT AS SOUNDINGS AND CROSS SECTIONS DO SHOW
A BIT OF LIFT IN THE SATURATED LAYER...WHICH IS FAIRLY LOW...BELOW
700MB. AS THE MOISTURE WON/T BE DEEP...A CONCERN IS PRECIPITATION
TYPE WITH THE STRONG COLD AIR ADVECTION DURING THE DAY SATURDAY.
AHEAD OF THE FRONT AT 12Z SATURDAY...MODEL SOLUTIONS ARE SHOWING
850MB TEMPERATURES OF 10C TO 12C AND BY 00Z SUNDAY RANGE FROM -13C
IN THE NORTHERN PANHANDLE TO AROUND 0C OVER SOUTH CENTRAL NEBRASKA.
BELIEVE WITH THIS DRASTIC MOVEMENT OF COLD AIR...WILL LIKELY SEE A
NON-DIURNAL CURVE FOR TEMPERATURES ON SATURDAY. AREAS ACROSS THE
NORTH WILL PROBABLY ONLY RISE INTO THE MID TO UPPER 30S AND LOW
40S...WHILE ACROSS THE SOUTHERN PART WILL BE MUCH WARMER. CURRENTLY
HAVE UPPER 40S AND LOW 50S IN THE FORECAST THINKING THERE WILL BE
GOOD MIXING RIGHT ALONG AND AHEAD OF THE FRONT TO BRING WARMER
TEMPERATURES TO THESE AREAS. THE COLD AIR LOOKS TO MOVE IN FAIRLY
UNIFORMLY ACCORDING TO FORECAST SOUNDINGS SO A GOOD WARM LAYER DOES
NOT SET UP...WHICH MEANS PRECIPITATION WILL START AS A RAIN/SNOW
MIX...THEN SWITCH QUICKLY TO SNOW BY LATE AFTERNOON SATURDAY. WITH
THE LACK OF FORCING...DON/T EXPECT TOO MUCH IN TERMS OF LIQUID
AMOUNTS. BUT AS THE COLUMN COOLS BY MORE OF THE SATURATED LAYER WILL
BE IN THE DENDRITIC GROWTH ZONE SO COULD GET SOME HIGH SNOW TO
LIQUID RATIOS TO GIVE UP TO A HALF INCH OF SNOW WITH ONLY A FEW
HUNDREDTHS OF LIQUID. AGAIN...THE LIFT IN THIS LAYER IS VERY MINIMAL
SO NOT EXPECTING MUCH FOR PRECIPITATION SO LEFT CHANCES FOR
MEASURABLE MOISTURE LOW AT THIS POINT.
DOESN`T LOOK TO BE A REAL DEEP LAYER OF MOISTURE AS THE MID LEVELS
LOOK PRETTY DRY. BUT WITH THE COLD AIR ADVECTION BEHIND THE
SYSTEM...THE LAYER THAT IS SATURATED FROM THE SURFACE TO AROUND
700MB...TEMPERATURES DROP THROUGH THE EVENING SO IT LOOKS COLD
ENOUGH FOR SNOW.
SUBSIDENCE TAKES OVER BY LATE SATURDAY NIGHT...WHICH WILL ALLOW THE
CHANCES FOR MEASURABLE PRECIPITATION TO END AFTER MIDNIGHT...THOUGH
WILL KEEP FLURRIES IN THE FORECAST INTO THE MORNING HOURS.
ALSO TO DISCUSS IS WINDS FOR SATURDAY AND SATURDAY NIGHT. A TIGHT
PRESSURE GRADIENT DEVELOPS BEHIND THE FRONT ON SATURDAY AND SATURDAY
NIGHT AND WITH GOOD SUBSIDENCE BEHIND THE SHORTWAVE COULD GET SOME
STRONG WINDS TO MIX DOWN TO THE SURFACE. ALTHOUGH SOME PLACES WON/T
MIX UP TO 850MB...LEVELS IN BETWEEN WILL ALSO SEE PRETTY STRONG
WINDS. AT 850MB...WINDS DO BLOW UP TO 50KTS SO WILL KEEP A CLOSE
LOOK IF THERE MIGHT BE A NEED FOR HEADLINES AT SOME POINT. THESE
WINDS STAY STRONG THROUGH MUCH OF SATURDAY NIGHT...AND WITH THE
STRONG WINDS AND THE COLD TEMPERATURES AND POTENTIALLY SOME LIGHT
SNOW...COULD BE AN INTERESTING NIGHT.
BEYOND SUNDAY...THE RIDGE BUILDS BACK IN OVER THE WEST COAST AND
WITH TROUGHING OVER THE EAST...ONCE AGAIN THE LOCAL AREA GETS STUCK
UNDER BROAD NORTHWEST FLOW. THROUGH THE REMAINDER OF THE PERIOD WILL
SEE A DECENT GRADIENT IN TEMPERATURES FROM NORTHEAST TO SOUTHWEST
ACROSS THE AREA. ALSO...THERE WILL BE A FEW WEAK IMPULSES OF ENERGY
MOVING THROUGH THE NORTHWEST FLOW ACROSS THE LOCAL AREA. THERE MAY
BE A FEW OPPORTUNITIES FOR SOME VERY LIGHT SNOWFALL...PRIMARILY OVER
NORTH CENTRAL NEBRASKA. THE TIMING OF ANY OF THESE SHORTWAVES IS
DIFFERENT BETWEEN MODELS SO NOT A GREAT DEAL OF CONFIDENCE RIGHT
NOW...BUT DO HAVE SOME LIGHT CHANCES IN FOR TUESDAY AND TUESDAY
NIGHT.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z FRIDAY MORNING)
ISSUED AT 535 AM CST THU DEC 26 2013
VFR THROUGH THE PERIOD IN BOTH LOCATIONS.
WEAK ECHOES SHOWING UP ON KLNX 88D CURRENTLY ASSOCIATED WITH VERY
WEAK MID LEVEL FRONTOGENESIS ASSOCIATED WITH UPPER PV ANOMALY
SWINGING THROUGH THE NORTHERN PLAINS. RAP PROXIMITY SOUNDINGS SHOW
A MID LEVEL CLOUD LAYER BUT VERY DRY BELOW SO AT THIS TIME AM NOT
EXPECTING ANY SPRINKLES OR FLURRIES MAKING IT TO THE GROUND. THIS
AREA OF MID LEVEL CLOUDINESS PASSES THROUGH THE AREA BY MID DAY TO
EARLY AFTERNOON WITH MAINLY CLEAR SKIES EXPECTED THEREAFTER. WINDS
MAY BE A BIT GUSTY BY LATE MORNING BUT SHOULD RELAX BY LATE
AFTERNOON OR EARLY EVENING.
&&
.LBF WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...JWS
SYNOPSIS...JWS
SHORT TERM...JWS
LONG TERM...BROOKS
AVIATION...JWS
AREA FORECAST DISCUSSION
NWS HASTINGS NE
557 AM CST THU DEC 26 2013
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 500 AM CST THU DEC 26 2013
WITH A CONTINUED EFFECTIVELY ZERO RISK OF PRECIP DURING THE NEXT
24 HOURS...TEMPS/SKY COVER/WIND SPEEDS REMAIN THE MAIN ISSUES. AS
DESCRIBED IN DETAIL BELOW...BOTH WIND SPEEDS AND ESPECIALLY TEMPS
HAVE BEEN BUMPED UP FOR TODAY...WITH THE MAIN WILD CARD FACTOR
BEING THE EXTENT/DURATION OF INCOMING MID-HIGH LEVEL CLOUDS.
ALTHOUGH MODELS SUCH AS THE NAM AND TO A MUCH LESSER EXTENT THE
RAP CONTINUE TO STRUGGLE WITH POORLY INITIALIZED/OVERDONE SNOW
COVER FIELDS...THE VERY LATEST 06Z NAM HAS FINALLY STARTED
LATCHING ONTO REALITY AND HOPEFULLY HELPS PAVE THE WAY FOR MORE
STRAIGHTFORWARD TEMP FORECASTING OVER THE NEXT FEW DAYS.
STARTING OFF EARLY THIS MORNING AS OF 0930Z THE LATEST 11-3.9
MICRON SATELLITE LOOP REVEALED PREDOMINANTLY CLEAR SKIES OVER THE
CWA...ALTHOUGH A FAIRLY DECENT BATCH OF MID-HIGH CLOUDS WAS
STEADILY APPROACHING THE AREA FROM SD. WATER VAPOR SATELLITE
IMAGERY AND SHORT TERM MODEL DATA DEPICTED CONTINUED NORTHWEST
MID-UPPER LEVEL FLOW OVER THE CENTRAL PLAINS...FLOWING BETWEEN A
LARGE SCALE TROUGH OVER THE EASTERN CONUS AND AN EXPANSIVE RIDGE
CENTERED ALONG/WEST OF THE PACIFIC COAST. ON THE SMALLER SCALE...A
FAIRLY SUBTLE DISTURBANCE WAS MAKING ITS WAY SOUTH-SOUTHEAST
ACROSS THE DAKOTAS AND IS LARGELY RESPONSIBLE FOR THE INCOMING
CLOUDS...WITH THIS FEATURE LOCATED WITHIN THE LEFT EXIT REGION OF
THE LATEST IN A SERIES OF 110+KT UPPER JET STREAKS POKING
SOUTHWARD INTO THE NORTHERN ROCKIES OUT OF SOUTHWESTERN CANADA. AT
THE SURFACE...09Z OBJECTIVE ANALYSIS AND AREA AUTOMATED OBS
REVEALED THE PRESENCE OF A SUBTLE NORTH-SOUTH TROUGH AXIS ACROSS
THE CWA...EXTENDING SOUTHWARD FROM A 1014 MILLIBAR LOW CENTERED
NEAR THE BORDER OF ND/SASKATCHEWAN/MANITOBA. MEANWHILE TO THE
SOUTH...A BROAD 1031MB HIGH WAS CENTERED OVER THE OK/WEST TX AREA.
THE NET RESULT OF THESE FEATURES IS A GENERALLY SOUTHWESTERLY
BREEZE OF 5-10 MPH ACROSS MOST OF THE CWA WITH SOME HIGHER GUSTS.
AS IS TYPICAL...THERE HAS BEEN AN EBB AND FLOW OF TEMPS OVERNIGHT
ACROSS THE CWA...AS THE FACTORS OF CLEAR SKIES AND LOCALIZED VERY
LIGHT BREEZES HAVE ALLOWED SOME PLACES TO FALL FAIRLY
EFFICIENTLY...WHILE OTHER PLACES INCLUDING THE TRI-CITIES HAVE
BEEN HELD UP FAIRLY WELL BY THE WESTERLY BREEZES. ALTHOUGH THESE
FLUCTUATIONS WILL CONTINUE THROUGH DAYBREAK...THE GENERAL
EXPECTATION IS THAT OVERNIGHT LOW TEMPERATURES ACROSS THE MAJORITY
OF THE CWA HAVE SETTLED/WILL SETTLE SOMEWHERE INTO THE 17-24 RANGE.
GETTING INTO THE DAYTIME FORECAST...THE BIG PICTURE ALOFT IN THE
MID-UPPER LEVELS INVOLVES THE CONTINUATION OF VERY SUBTLE HEIGHT
RISES AS EVIDENT AT 500MB...AS THE DISTURBANCE CURRENTLY CENTERED
OVER THE DAKOTAS TRACKS SOUTHEAST OVER MAINLY EASTERN PORTIONS OF
THE LOCAL AREA...BUT ESPECIALLY INTO THE IA/MN AREA...ALLOWING THE
WESTERN RIDGE TO NUDGE EVER SO SLIGHTLY EAST INTO THE CENTRAL PLAINS.
AS THIS OCCURS...THE TRAILING NORTH-SOUTH ORIENTED UPPER JET
STREAK WILL ALSO SLIDE EAST FROM THE NORTHERN ROCKIES INTO THE
DAKOTAS OVER THE COURSE OF THE DAY. AT THE SURFACE TODAY...THERE
WILL BE A SIMILAR SCENARIO TO WHAT OCCURRED YESTERDAY...AS
INITIALLY SOUTHWESTERLY BREEZES WILL SWITCH TO NORTHWESTERLY IN
RESPONSE TO THE EASTWARD PROGRESSION OF THE PARENT SURFACE TROUGH
CENTERED TO THE NORTH. AS MIXING HEIGHTS INCREASE TO THE 900-875MB
RANGE PER RAP SOUNDINGS...WIND SPEEDS WILL PICK UP WITH SUSTAINED
NORTHWESTERLY SPEEDS OF 15-20 MPH AND GUSTS UP TO AROUND 25
MPH...WITH THE MAIN TIME FRAME OF STRONGEST BREEZES CENTERED
BETWEEN LATE MORNING AND MID-AFTERNOON BEFORE SUBSIDING AGAIN
LATER IN THE AFTERNOON. THESE WIND SPEEDS REFLECT ROUGHLY A 5 MPH
INCREASE VERSUS PREVIOUS FORECAST FOR MUCH OF THE AREA. TURNING TO
SKY COVER...THIS IS A BIT OF A QUESTION MARK TODAY AS MODELS ARE
HANDLING THE INCOMING CLOUD DECK SOMEWHAT DIFFERENTLY. THE GENERAL
EXPECTATION THOUGH IS THAT ALTHOUGH ESPECIALLY NORTHERN PARTS OF
THE AREA COULD GO MOSTLY CLOUDY FOR A TIME THIS MORNING...THE
OVERALL DENSITY OF THIS CLOUD DECK SHOULD FADE WITH TIME AND WITH
SOUTHWARD EXTENT...RESULTING IN NO WORSE THAN PARTLY CLOUDY IF NOT
MOSTLY SUNNY CONDITIONS THROUGH THE BALANCE OF THE DAY. PUT
ANOTHER WAY...THE CURRENT SKY COVER GRIDS MAY NOT BE QUITE
AGGRESSIVE ENOUGH FOR LATER THIS MORNING...BUT THINK THAT THE DAY
OVERALL WILL FEATURE MORE SUN THAN CLOUDS. AS FOR TEMPS TODAY...FOR
NOW WILL ASSUME A RATHER NEGLIGIBLE EFFECT OF PASSING CLOUD
COVER...AND THUS GIVEN THE DECENT LOW LEVEL MIXING REGIME IN
PLACE...HAVE BOOSTED HIGH TEMPS AT LEAST A FEW DEGREES VERSUS
PREVIOUS FORECAST ACROSS THE NORTHERN HALF OF THE CWA...AND AS
MUCH AS 5-9 DEGREES IN THE SOUTH. BASED ON WHAT HAPPENED
YESTERDAY...NEARLY ALL PRIMARY MODELS/GUIDANCE FELL AT LEAST
SLIGHTLY SHORT OF ACTUAL HIGHS...BUT HOURLY RAP13 TEMPS ENDED UP
BEING ONE OF THE BEST SOLUTIONS. AS A RESULT...HAVE AGAIN OPTED TO
FOLLOW RAP13 TEMPS QUITE CLOSELY TODAY...WHICH RESULTS IN HIGHS
GENERALLY 4-7 DEGREE WARMER THAN A SIMPLE BLEND OF 00Z MET/MAV
GUIDANCE. THE NET RESULT IS HIGH TEMPERATURES AIMED FROM THE UPPER
40S/LOW 50S IN THE NORTHERN 1/2 OF THE CWA TO PREDOMINANTLY MID-
50S IN KS ZONES. IF ANYTHING...MIGHT NOT HAVE GONE WARM ENOUGH IN
NORTHEAST ZONES. THIS INCREASE IN HIGH TEMPS RESULTS IN AFTERNOON
RELATIVE HUMIDITY VALUES FORECAST TO DROP AROUND 25 PERCENT OR
SLIGHTLY LOWER IN SOUTHWESTERN COUNTIES...BUT GIVEN THAT SUSTAINED
WINDS SHOULD AVERAGE CLOSER TO 15 MPH THAN 20 MPH IN THESE
AREAS...THE SETUP APPEARS TO FALL A BIT SHORT OF JUSTIFYING A
NEAR-CRITICAL FIRE DANGER MENTION IN THE HAZARDOUS WEATHER
OUTLOOK.
TURNING TO THIS EVENING/TONIGHT...THE LARGE SCALE SYNOPTIC PICTURE
INVOLVES THE CONTINUED EXPANSION OF THE WESTERN CONUS RIDGE
EASTWARD OVER THE CENTRAL PLAINS...ACCOMPANIED BY RESULTANT MID-
LEVEL HEIGHT RISES. ALTHOUGH THE PRIMARY UPPER JET CORE WILL
CONTINUE TO SLIDE OFF TO THE NORTH-NORTHEAST OF THE AREA...THE
CONTINUED NORTH-NORTHWESTERLY FLOW ALOFT OVER THE CENTRAL PLAINS
WILL NONETHELESS FEATURE THE PASSAGE OF AT LEAST ONE SUBTLE...LOW-
AMPLITUDE SHORTWAVE TROUGH DURING THE NIGHT. ALTHOUGH THIS COULD
EASILY RESULT IN A MODEST INCREASE IN MID-HIGH LEVEL CLOUDS MAINLY
AFTER MIDNIGHT AND MAINLY IN NORTHERN ZONES...THE NIGHT AS A WHOLE
SHOULD AVERAGE NO WORSE THAN MOSTLY CLEAR ACROSS THE ENTIRE CWA.
AT THE SURFACE TONIGHT...A NOW-FAMILIAR PATTERN WILL AGAIN REPEAT
ITSELF...AS A SUBTLE TROUGH AXIS WILL AGAIN EXTEND SOUTHWARD INTO
THE CENTRAL PLAINS FROM A PARENT LOW PRESSURE SYSTEM CENTERED WELL
TO THE NORTH OVER SOUTH CENTRAL CANADA. THIS WILL AGAIN TRANSITION
THE NORTHWESTERLY BREEZES OF THIS AFTERNOON TO FAIRLY LIGHT
WESTERLY BREEZES THIS EVENING...AND THEN 5-10 MPH SOUTHWESTERLY
BREEZES AFTER MIDNIGHT. WITH THE SKY COVER...WIND SPEED/DIRECTION
AND LOW LEVEL THERMAL PROFILES TONIGHT SETTING UP TO BE QUITE
SIMILAR TO THOSE OF THIS MORNING...SEE NO REASON WHY TEMPERATURE
BEHAVIOR WON/T BE SIMILAR AS WELL...WITH PLENTY OF HOUR-TO-HOUR
AND SMALL-SCALE VARIABILITY. ALTHOUGH VERY LITTLE CHANGE WAS MADE
TO LOWS FROM THE PREVIOUS FORECAST...STILL CALLING FOR NEARLY THE
ENTIRE CWA TO SETTLE WITHIN A FEW DEGREES EITHER SIDE OF 20 AT
SOME POINT IN THE NIGHT...THIS IS STILL A FEW DEGREES ABOVE A
STRAIGHT-UP 00Z MET/MAV GUIDANCE BLEND...AND WOULD NOT BE
SURPRISED IF THE NEXT SHIFT CONSIDERS RAISING LOWS A BIT MORE IN
SOME PLACES.
.LONG TERM...(FRIDAY THROUGH WEDNESDAY)
ISSUED AT 500 AM CST THU DEC 26 2013
THE BIGGEST CHALLENGE WILL BE DETERMINING THE TIMING OF A COLD FRONT
SATURDAY...WHICH WILL SUBSEQUENTLY AFFECT HIGH TEMPERATURES ON
SATURDAY AND WIND SPEEDS SATURDAY/SATURDAY NIGHT.
WE BEGIN THE LONG TERM FORECAST IN A TRANSITION OF SORTS. THE RIDGE
OVER THE WESTERN UNITED STATES WILL DEAMPLIFY AS IT MOVES
EAST...BEING BROKEN DOWN BY AN APPROACHING SHORTWAVE TROUGH ENTERING
THE COAST OF THE PACIFIC NORTHWEST BY LATE DAY FRIDAY. WE WILL
CLEARLY BE IN THE WARM SECTOR WITH HIGHS EASILY REACHING THE 50S FOR
MOST LOCATIONS IF NOT 60 FOR MUCH OF NORTH CENTRAL KANSAS. MODEL
OUTPUT IS NOT OPTIMAL FOR MAXIMUM TEMPERATURE FORECASTS AS A PHANTOM
SNOWPACK LINGERS OVER MUCH OF THE AREA AND IS DISTURBING THE MODEL
SOLUTIONS...ESPECIALLY FOR MAX T AND WIND FIELDS. REALLY HAD TO LEAN
ON ENSEMBLE DATA AND OPERATIONAL MODELS SUCH AS THE ECMWF THAT
EITHER DO NOT INCLUDE SNOWPACK...OR HAVE LIMITED SNOWPACK DATA
ENTERED INTO MODEL INITIALIZATIONS. THE NAM...SPECIFICALLY...IS
ATROCIOUS AND HAS AFFECTED OTHER SOLUTIONS SUCH AS
CONSRAW...BCCONSRAW...CONSALL...ETC. THIS HAS RENDERED MUCH OF THESE
DATA RATHER USELESS FOR MAXIMUM TEMPERATURE AND WIND FIELDS.
I WENT CLOSER TO CONSRAW OUTPUT FOR MINIMUM TEMPERATURES FRIDAY
NIGHT AS THIS OUTPUT SEEMED TO BE LARGELY UNAFFECTED BY THE
ERRONEOUS SNOWPACK AND THIS OUTPUT TENDS TO DO BEST FOR LOW
TEMPERATURES FOR THE LAST NIGHT BEFORE A COLD FRONT PASSAGE. THE
SREF ADVERTISES QUITE A BIT OF FOG FOR FRIDAY NIGHT...ESPECIALLY IN
OUR EAST...BUT WITH A SOUTHWEST WIND THAT WILL NOT BE PARTICULARLY
LIGHT...I AM DISCOUNTING THIS ADVERTISEMENT.
SATURDAY WILL BE TRICKY AS THE AFOREMENTIONED TROUGH TO THE NORTHWEST
SWEEPS RATHER QUICKLY INTO THE PLAINS...JOINING WITH ANOTHER TROUGH
SWINGING DOWN FROM CANADA TO REINFORCE A SIGNIFICANT SHOT OF MUCH
COLDER AIR. THE TRICKY PART WILL BE TIMING THE ASSOCIATED COLD
FRONT. MODEL SOLUTIONS GENERALLY CONCUR THAT MOST OF THE CWA SHOULD
BE ABLE TO GET IN ONE MORE DAY OF GOOD WARM AIR ADVECTION AHEAD OF
THE COLD FRONT BEFORE IT COMES IN. THE FAR WESTERN AND NORTHERN CWA
ARE MOST AT RISK OF NOT REALIZING TEMPERATURES AS WARM OR WARMER
THAN WHAT OCCURRED ON FRIDAY. I INCREASED TEMPERATURES FOR MOST OF
THE CWA FROM THE PREVIOUS FORECAST...BUT KEPT TEMPERATURES IN THE FAR
WESTERN/NORTHWESTER CWA RATHER SIMILAR AS MEDIUM RANGE MODELS
INDICATE THAT THE COLD FRONT SHOULD MAKE ITS WAY JUST INTO THE CWA
BY NOON SATURDAY. HOWEVER...THE FORECAST FOR MID 50S FOR SATURDAY
COULD CRASH AND BURN RATHER EASILY IF THE COLD AIR COMES IN
FASTER...SO THE CONFIDENCE FOR HIGH TEMPERATURES...ESPECIALLY FROM
THE TRI-CITIES AND FARTHER NORTHWEST...IS NOT AS HIGH AS IT COULD
BE...ESPECIALLY WITH THE POOR MODEL OUTPUT AS OF LATE. HEIGHT RISES
ARE IMPRESSIVE ALONG WITH COLD AIR ADVECTION BEHIND THE COLD
FRONT...ALTHOUGH THESE VARIABLES REALLY TAKE HOLD LATER INTO SATURDAY
NIGHT. I RAISED WIND SPEEDS SIGNIFICANTLY FROM THE PREVIOUS FORECAST
BECAUSE OF THIS...AND WE SHOULD BE IN THE REALM OF WIND ADVISORY AS
FAR SOUTH AS THE TRI-CITIES...AND NOT TOO FAR FROM WIND ADVISORY
FARTHER SOUTH IN OUR CWA FOR SATURDAY NIGHT. THIS CONTINUES TO LOOK
LIKE A DRY FORECAST WITH THE PASSING OF THE COLD FRONT AS THE
MOISTURE PROFILE IS QUITE DRY...ALTHOUGH THERE COULD CERTAINLY BE
SOME STRATUS FOR AWHILE DUE TO THE STRONG COLD AIR ADVECTION AND A
FLURRY IS NOT COMPLETELY OUT OF THE QUESTION. ALTHOUGH MID-LEVELS
ARE QUITE DRY...ANY SATURATION WILL OCCUR AT TEMPERATURES FAR TOO
COLD TO SUPPORT FREEZING DRIZZLE. THE COMBINATION OF THE STRATUS AND
WIND SHOULD KEEP TEMPERATURES FROM BOTTOMING OUT TOO MUCH AND THE
TEMPERATURES FROM THE PREVIOUS FORECAST LOOK PERFECTLY REASONABLE.
JUDGING BY WHAT HAPPENED WITH THE LAST COLD SNAP...I SUSPECT THAT
MODELS ARE GOING TO WANT TO SCOOT THE COLD AIR TO THE EAST TOO
QUICKLY AS THE DEVELOPING UPPER LEVEL RIDGE TO THE WEST TRIES TO
BUILD EAST. THIS IS CONFIRMED BY ENSEMBLE TRENDS FROM THE ECMWF AND
THE GFS. I WENT COLDER THAN THE INITIALIZED ALLBLEND AND PREVIOUS
FORECASTS...ESPECIALLY FOR HIGHS SUNDAY AND MONDAY...AND ALSO LOWS
FOR SUNDAY NIGHT/MONDAY MORNING. THE CENTER OF THE SURFACE HIGH
SHOULD MAKE ITS WAY ACROSS THE CWA SUNDAY NIGHT/MONDAY MORNING TO
ALLOW WINDS TO DROP SIGNIFICANTLY. UNDER CLEAR/MOSTLY CLEAR SKIES
AND WIND BECOMING VERY LIGHT OR CALM NEAR THE CENTER OF THE SURFACE
HIGH...THIS SHOULD ALLOW TEMPERATURES TO REALLY TANK INTO THE SINGLE
DIGITS...AND THEY COULD TANK RELATIVELY EARLY IN THE
NIGHT...DEPENDING ON THE TIMING OF THE SURFACE HIGH.
ONE MORE THING OF NOTE...I STUCK IN A SLIGHT CHANCE OF SNOW IN THE
NORTHEASTERN CWA FOR WEDNESDAY FROM AN IMPULSE WITHIN NORTHWEST
FLOW. TIMING AND POSITIONING ARE DICEY...SO CHANCES OF PRECIPITATION
ARE NOT HIGH IN THE FORECAST. SINCE MORE THAN ONE MODEL SOLUTION
ADVERTISES A SHORTWAVE TROUGH MOVING IN AT ROUGHLY THIS TIME...IT IS
PRUDENT TO INTRODUCE THIS TO THE LONG TERM FORECAST.
&&
.AVIATION...(FOR THE 12Z KGRI TAF THROUGH 12Z FRIDAY MORNING)
ISSUED AT 557 AM CST THU DEC 26 2013
CONFIDENCE REMAINS HIGH IN VFR CEILING/VISIBILITY THROUGH THE NEXT
24 HOURS...WITH ONLY LIMITED COVERAGE OF PASSING MID-HIGH LEVEL
CLOUDS. THAT LEAVES SURFACE WINDS AS THE MAIN ISSUE. BOTH EARLY
THIS MORNING AND AGAIN THIS EVENING/TONIGHT...WINDS WILL AVERAGE
FROM SOME VARIATION OF WESTERLY AT SUSTAINED SPEEDS GENERALLY
NEAR/UNDER 10KT. HOWEVER...FOR SEVERAL HOURS DURING THE HEART OF
THE DAY...ESPECIALLY BETWEEN 17-21Z...THERE WILL LIKELY BE A
PERIOD OF ENHANCED NORTHWEST BREEZES BEHIND A PASSING SURFACE
TROUGH AS VERTICAL MIXING INCREASES. DURING THIS TIME...WIND GUST
POTENTIAL WILL INCREASE TO AROUND 20KT BEFORE SUBSIDING BY LATE
AFTERNOON. ALTHOUGH THERE WILL BE A DIRECTIONAL CHANGE FROM
NORTHWESTERLY TO SOUTHWESTERLY OVERNIGHT...FORECAST SPEEDS ARE NOT
HIGH ENOUGH TO JUSTIFY AN ADDITIONAL FROM-GROUP AFTER 00Z.
&&
.GID WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
KS...NONE.
&&
$$
SHORT TERM...PFANNKUCH
LONG TERM...HEINLEIN
AVIATION...PFANNKUCH
AREA FORECAST DISCUSSION
NWS NORTH PLATTE NE
535 AM CST THU DEC 26 2013
.SYNOPSIS...
ISSUED AT 343 AM CST THU DEC 26 2013
NEXT IN THE SERIES OF UPPER PV ANOMALIES...CURRENTLY LOCATED OVER
ERN MT...WILL DROP ACROSS THE NORTHERN PLAINS TODAY...ORIGINATING
FROM THE NORTHERN PACIFIC REGION INSTEAD OF THE ARCTIC. AHEAD OF THE
FEATURES WESTERLY OR SOUTHWESTERLY COMPONENT TO THE WINDS JUST OFF
THE SURFACE IS BRINGING WARMER AIR TO THE WESTERN HIGH PLAINS AND
CONTINUING INTO THE MORNING HOURS. AT THE HEMISPHERIC SCALE...A
PROGRESSIVE PATTERN REMAINS ACROSS THE NORTHERN HEMISPHERE WITH AN
UPPER LOW MOVING QUICKLY INTO THE ERN U.S. AND HIGH PRESSURE ALOFT
BUILDING INTO THE PAC NW.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 343 AM CST THU DEC 26 2013
PREVIOUSLY MENTIONED PV ANOMALY DIVES SOUTHEAST ACROSS THE NORTHERN
PLAINS WHICH WILL DRIVE A WEAK COLD FRONT ACROSS THE AREA LATER IN
THE DAY. BRIEF WARM AIR ADVECTION THIS MORNING WILL ALLOW TEMPS TO
BE WARMER THAN YESTERDAY AND ALTHOUGH WINDS WILL BECOME NWRLY BY
AFTERNOON...COOLER AIR LAGS THE WEAK FRONT SOMEWHAT AND IS WEAK
ESPECIALLY IN THE WEST. IN ADDITION...JET DYNAMICS ARE NOT FAVORABLE
FOR LARGE SCALE ASCENT AND DRIER AIR IN THE MID LEVELS ACCOMPANYING
THE WARMER AIR AHEAD OF THE SYSTEM WOULD PRECLUDE ANY PRECIP
DEVELOPMENT ANYWAY. RESULT IS SOME MID AND HIGH CLOUDS BY LATE
MORNING INTO THE AFTERNOON...COVERAGE SHOULD NOT LIMIT MAX TEMPS
FROM REACHING LEVELS 10 TO 12 DEGREES ABOVE AVERAGE IN THE
SOUTH...BUT ONLY A FEW DEGREES ABOVE AVE IN THE NORTH. STILL SOME
SNOW COVER ACROSS SHERIDAN AND WESTERN CHERRY COUNTIES SO SOME
INFLUENCE ON TEMPS THERE...BUT OTHERWISE MAINLY OPEN GROUND. NAM
TEMPS ARE HEAVILY INFLUENCED STILL BY HAVING TOO MUCH SNOW COVER
ANALYZED.
UPPER RIDGE BUILD ACROSS THE WEST OVER NIGHT WITH GOOD SUBSIDENCE
CLEARING CLOUDS. WILL ALLOW FOR GOOD RADIATIONAL COOLING BUT LOW
TEMPS STILL ABOVE AVE FOR THIS TIME OF YEAR.
.LONG TERM...(FRIDAY THROUGH WEDNESDAY)
ISSUED AT 343 AM CST THU DEC 26 2013
FORECAST FOCUS FOR FRIDAY INTO SATURDAY IS TEMPERATURES. THE THERMAL
RIDGE ALOFT KEEPS TEMPERATURES ABNORMALLY WARM...WITH 850MB
TEMPERATURES AT 9C TO 11C FRIDAY AND FRIDAY NIGHT. MODELS
/ESPECIALLY THE NAM/ ARE HAVING SOME ISSUES WITH THE SNOW
COVER...AND THUS THE AMOUNT OF MIXING/WARMING THAT WILL BE REALIZED
ON FRIDAY. THERE MAY BE SOME HIGH CLOUDS BUT NOT EXPECTING ENOUGH TO
MAKE A HUGE IMPACT ON HIGHS. WILL ALSO HAVE BREEZY WESTERLY WINDS TO
ENHANCE THE DOWNSLOPE WARMING EFFECT...AND HELP WARM TEMPERATURES TO
THE UPPER 40S AND 50S. LOWS FRIDAY NIGHT SHOULD STAY FAIRLY MILD AS
THE WINDS STAY UP AND CLOUDS INCREASE DUE TO AN INCOMING FRONTAL
BOUNDARY.
AN UPPER LEVEL TROUGH WILL PASS ACROSS THE PLAINS SATURDAY NIGHT
INTO SUNDAY. MODEL SOLUTIONS ARE IN GOOD AGREEMENT THAT IMPACT
LOCALLY WILL BE MINIMAL...WITH THE PRIMARY CONCERNS BEING A CHANGE
IN TEMPERATURES.
THERE ARE TWO PRIMARY PV ANOMALIES THAT WILL MOVE THROUGH THE
TROUGH...THE FIRST ORIGINATES OVER THE YUKON AND NORTHWEST
TERRITORIES WHICH THEN DIGS SOUTHWARD AND MOVES THROUGH THE DAKOTAS
ON SUNDAY. THE SECOND IS THE SYSTEM CURRENTLY OUT OVER THE NORTHERN
PACIFIC WHICH WILL MOVE EAST AND DAMPEN THE RIDGE AND MOVE INTO THE
PACIFIC NORTHWEST FRIDAY THEN PROGRESS THROUGH THE TROUGH WITH THE
MAIN PART OF THE PV ANOMALY STAYING WELL SOUTH OF THE FORECAST
AREA...THROUGH THE FOUR CORNERS AND INTO THE SOUTHERN PLAINS. THESE
TWO BITS OF ENERGY WILL NOT PHASE TOGETHER SO UPWARD FORCING WILL
NOT BE GREAT IN THE LOCAL AREA AS THESE SYSTEMS PASS. DID KEEP LOW
CHANCES ACROSS NORTHERN NEBRASKA INTO THE PANHANDLE ON SATURDAY
AFTERNOON AND SATURDAY NIGHT AS SOUNDINGS AND CROSS SECTIONS DO SHOW
A BIT OF LIFT IN THE SATURATED LAYER...WHICH IS FAIRLY LOW...BELOW
700MB. AS THE MOISTURE WON/T BE DEEP...A CONCERN IS PRECIPITATION
TYPE WITH THE STRONG COLD AIR ADVECTION DURING THE DAY SATURDAY.
AHEAD OF THE FRONT AT 12Z SATURDAY...MODEL SOLUTIONS ARE SHOWING
850MB TEMPERATURES OF 10C TO 12C AND BY 00Z SUNDAY RANGE FROM -13C
IN THE NORTHERN PANHANDLE TO AROUND 0C OVER SOUTH CENTRAL NEBRASKA.
BELIEVE WITH THIS DRASTIC MOVEMENT OF COLD AIR...WILL LIKELY SEE A
NON-DIURNAL CURVE FOR TEMPERATURES ON SATURDAY. AREAS ACROSS THE
NORTH WILL PROBABLY ONLY RISE INTO THE MID TO UPPER 30S AND LOW
40S...WHILE ACROSS THE SOUTHERN PART WILL BE MUCH WARMER. CURRENTLY
HAVE UPPER 40S AND LOW 50S IN THE FORECAST THINKING THERE WILL BE
GOOD MIXING RIGHT ALONG AND AHEAD OF THE FRONT TO BRING WARMER
TEMPERATURES TO THESE AREAS. THE COLD AIR LOOKS TO MOVE IN FAIRLY
UNIFORMLY ACCORDING TO FORECAST SOUNDINGS SO A GOOD WARM LAYER DOES
NOT SET UP...WHICH MEANS PRECIPITATION WILL START AS A RAIN/SNOW
MIX...THEN SWITCH QUICKLY TO SNOW BY LATE AFTERNOON SATURDAY. WITH
THE LACK OF FORCING...DON/T EXPECT TOO MUCH IN TERMS OF LIQUID
AMOUNTS. BUT AS THE COLUMN COOLS BY MORE OF THE SATURATED LAYER WILL
BE IN THE DENDRITIC GROWTH ZONE SO COULD GET SOME HIGH SNOW TO
LIQUID RATIOS TO GIVE UP TO A HALF INCH OF SNOW WITH ONLY A FEW
HUNDREDTHS OF LIQUID. AGAIN...THE LIFT IN THIS LAYER IS VERY MINIMAL
SO NOT EXPECTING MUCH FOR PRECIPITATION SO LEFT CHANCES FOR
MEASURABLE MOISTURE LOW AT THIS POINT.
DOESN`T LOOK TO BE A REAL DEEP LAYER OF MOISTURE AS THE MID LEVELS
LOOK PRETTY DRY. BUT WITH THE COLD AIR ADVECTION BEHIND THE
SYSTEM...THE LAYER THAT IS SATURATED FROM THE SURFACE TO AROUND
700MB...TEMPERATURES DROP THROUGH THE EVENING SO IT LOOKS COLD
ENOUGH FOR SNOW.
SUBSIDENCE TAKES OVER BY LATE SATURDAY NIGHT...WHICH WILL ALLOW THE
CHANCES FOR MEASURABLE PRECIPITATION TO END AFTER MIDNIGHT...THOUGH
WILL KEEP FLURRIES IN THE FORECAST INTO THE MORNING HOURS.
ALSO TO DISCUSS IS WINDS FOR SATURDAY AND SATURDAY NIGHT. A TIGHT
PRESSURE GRADIENT DEVELOPS BEHIND THE FRONT ON SATURDAY AND SATURDAY
NIGHT AND WITH GOOD SUBSIDENCE BEHIND THE SHORTWAVE COULD GET SOME
STRONG WINDS TO MIX DOWN TO THE SURFACE. ALTHOUGH SOME PLACES WON/T
MIX UP TO 850MB...LEVELS IN BETWEEN WILL ALSO SEE PRETTY STRONG
WINDS. AT 850MB...WINDS DO BLOW UP TO 50KTS SO WILL KEEP A CLOSE
LOOK IF THERE MIGHT BE A NEED FOR HEADLINES AT SOME POINT. THESE
WINDS STAY STRONG THROUGH MUCH OF SATURDAY NIGHT...AND WITH THE
STRONG WINDS AND THE COLD TEMPERATURES AND POTENTIALLY SOME LIGHT
SNOW...COULD BE AN INTERESTING NIGHT.
BEYOND SUNDAY...THE RIDGE BUILDS BACK IN OVER THE WEST COAST AND
WITH TROUGHING OVER THE EAST...ONCE AGAIN THE LOCAL AREA GETS STUCK
UNDER BROAD NORTHWEST FLOW. THROUGH THE REMAINDER OF THE PERIOD WILL
SEE A DECENT GRADIENT IN TEMPERATURES FROM NORTHEAST TO SOUTHWEST
ACROSS THE AREA. ALSO...THERE WILL BE A FEW WEAK IMPULSES OF ENERGY
MOVING THROUGH THE NORTHWEST FLOW ACROSS THE LOCAL AREA. THERE MAY
BE A FEW OPPORTUNITIES FOR SOME VERY LIGHT SNOWFALL...PRIMARILY OVER
NORTH CENTRAL NEBRASKA. THE TIMING OF ANY OF THESE SHORTWAVES IS
DIFFERENT BETWEEN MODELS SO NOT A GREAT DEAL OF CONFIDENCE RIGHT
NOW...BUT DO HAVE SOME LIGHT CHANCES IN FOR TUESDAY AND TUESDAY
NIGHT.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z FRIDAY MORNING)
ISSUED AT 535 AM CST THU DEC 26 2013
VFR THROUGH THE PERIOD IN BOTH LOCATIONS.
WEAK ECHOES SHOWING UP ON KLNX 88D CURRENTLY ASSOCIATED WITH VERY
WEAK MID LEVEL FRONTOGENESIS ASSOCIATED WITH UPPER PV ANOMALY
SWINGING THROUGH THE NORTHERN PLAINS. RAP PROXIMITY SOUNDINGS SHOW
A MID LEVEL CLOUD LAYER BUT VERY DRY BELOW SO AT THIS TIME AM NOT
EXPECTING ANY SPRINKLES OR FLURRIES MAKING IT TO THE GROUND. THIS
AREA OF MID LEVEL CLOUDINESS PASSES THROUGH THE AREA BY MID DAY TO
EARLY AFTERNOON WITH MAINLY CLEAR SKIES EXPECTED THEREAFTER. WINDS
MAY BE A BIT GUSTY BY LATE MORNING BUT SHOULD RELAX BY LATE
AFTERNOON OR EARLY EVENING.
&&
.LBF WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...JWS
SHORT TERM...JWS
LONG TERM...BROOKS
AVIATION...JWS
AREA FORECAST DISCUSSION
NWS GRAND FORKS ND
249 PM CST THU DEC 26 2013
.SHORT TERM...(THIS EVENING THROUGH FRIDAY NIGHT)
ISSUED AT 248 PM CST THU DEC 26 2013
TEMPERATURES WILL BE THE MAIN FORECAST ISSUE FOR THE SHORT TERM.
NORTHWESTERLY FLOW ALOFT WILL CONTINUE OVER THE REGION UNTIL AN
UPPER TROUGH STARTS TO DIG INTO MONTANA FRIDAY NIGHT. UNTIL
THEN...CONDITIONS WILL BE FAIRLY QUIET FOR THE CWA. A WEAK
SHORTWAVE OVER MANITOBA TONIGHT MOVES OFF INTO ONTARIO BY FRIDAY.
THE CENTER OF THE SFC LOW AND MOST OF THE PRECIP WILL REMAIN TO
OUR NORTH. ALTHOUGH SOME SNOW MAY CLIP LAKE OF THE WOODS SO KEPT
LOW POPS GOING IN OUR FAR NORTHEAST. A GREATER IMPACT ON US WILL
BE WESTERLY SFC WINDS BEHIND THE SFC TROUGH AXIS. THESE WEST WINDS
AND SOME LINGERING STRATUS WILL KEEP TEMPS TONIGHT FROM DROPPING
TOO MUCH...STAYING IN THE SINGLE DIGITS ABOVE ZERO IN THE EAST AND
THE TEENS IN THE WEST. WEST WINDS WILL CONTINUE TO BRING WARM AIR
ADVECTION TO THE REGION THROUGH FRIDAY...WITH 850MB TEMPS GETTING
WELL ABOVE ZERO. TEMPS TODAY OVER CENTRAL ND HAVE CLIMBED INTO THE
UPPER 20S TO LOW 30S EVEN WITH CLOUD COVER...SO THINK THAT WITH A
LITTLE BIT OF SUN WE SHOULD GET INTO THE MID 30S OVER THE
SOUTHWESTERN COUNTIES WITH SLIGHT COOLER TEMPS FURTHER NORTHEAST.
THE WARM UP WILL NOT LAST LONG AS THE ARCTIC FRONT BEGINS TO MOVE
DOWN INTO THE CWA FRIDAY NIGHT. SOME LIGHT SNOW WILL BE POSSIBLE
ALONG THE FRONTAL BOUNDARY...MAINLY IN THE FAR NORTH FRIDAY NIGHT.
WITH VERY STRONG COLD AIR ADVECTION TEMPS SHOULD SEE A SHARP DROP
INTO THE SINGLE DIGITS EVEN WITH CLOUDS BY SATURDAY MORNING.
.LONG TERM...(SATURDAY THROUGH THURSDAY)
ISSUED AT 248 PM CST THU DEC 26 2013
SATURDAY AND SUNDAY...THE BITTER ARCTIC AIR MAKES AN UNWANTED
ENCORE WITH HIGH PRESSURE BUILDING IN. THE PRESSURE GRADIENT
BEHIND THE COLD FRONT WILL BE PRETTY TIGHT AND A GOOD DIRECTION
FOR FUNNELING RIGHT DOWN THE VALLEY. THERE WILL BE A DECENT
ADIABATIC LAPSE RATE TO 925MB...ALTHOUGH THE GFS AND NAM ARE
SHOWING ABOUT 25 TO 30 KTS TO MIX. THE ECMWF ON THE OTHER
HAND...HAS NEARLY 40 KTS RIGHT OFF THE DECK. CONTINUED THE STRONG
WINDS DURING THE DAY ON SATURDAY AND THE MENTION OF WIDESPREAD
BLOWING SNOW FOR AT LEAST PART OF THE RED RIVER VALLEY.
HOWEVER...DO NOT FEEL CONFIDENT AT THIS POINT TO GO WITH ANY KIND
OF HEADLINE AND WILL JUST KEEP THE SPS GOING. WINDS WILL BEGIN TO
DIMINISH AND SKIES CLEAR OUT SATURDAY NIGHT...ALLOWING A DROP TO
NEAR 20 BELOW. COLD HIGH PRESSURE WILL BRING QUIET CONDITIONS BUT
WILL KEEP TEMPS IN THE NEGATIVE NUMBERS FOR SUNDAY.
SUNDAY NIGHT THROUGH THURSDAY...A NORTHWEST FLOW UPPER PATTERN
WILL DOMINATE NEXT WEEK...WITH MINOR EMBEDDED SHORTWAVES IN THE
MON AND WED TIMEFRAME POSSIBLY BRINGING SOME LIGHT SNOW (MORE
LIKELY FLURRIES) TO THE DEVILS LAKE REGION. EXPECT THE WEEK TO BE
DRY FURTHER EAST IN EASTERN ND...THE VALLEY AND NORTHWEST AND WEST
CENTRAL MINNESOTA. ANY CLOUDS RESULTING FROM THE WEAK WAVES WILL
BE WELCOME...AS A FRIGID ARCTIC AIRMASS WILL BE IN PLACE FROM SUN
NIGHT THROUGH MID WEEK. TEMPS SHOULD BE IN THE 20S BELOW OVERNIGHT
THROUGH WED...UNLESS CLOUDS CAN PROVIDE SOME RELIEF.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z FRIDAY AFTERNOON)
ISSUED AT 1226 PM CST THU DEC 26 2013
THE LATEST RAP GUIDANCE IS SHOWING IFR CIGS OVER CNTRL ND GRADUALLY
SHIFTING EAST THROUGH THE NEXT 24 HOURS WHILE THE NAM/GFS MOS
GUIDANCE KEEPS CONDS MVFR. I WILL GO WITH THE RAP IDEA AS IT IS
VERIFYING WELL NOW...AND BRING IFR CIGS INTO THE VALLEY BY LATE AFTN
AND INTO TVF/BJI BY MIDNIGHT. THINGS SHOULD THEN START IMPROVING
ACROSS EASTERN ND BY MIDNIGHT...WITH LESS UNCERTAINTY WHEN IFR CIGS
WILL ERODE AT TVF/BJI...BUT DO EXPECT CLEARING BY END OF 18Z TAF
PERIOD.
&&
.FGF WATCHES/WARNINGS/ADVISORIES...
ND...NONE.
MN...NONE.
&&
$$
SHORT TERM...JR
LONG TERM...JR/SPEICHER
AVIATION...SPEICHER
AREA FORECAST DISCUSSION
NWS GRAND FORKS ND
1227 PM CST THU DEC 26 2013
.UPDATE...
ISSUED AT 1226 PM CST THU DEC 26 2013
MOST SIGNIFICANT SNOW HAS ENDED ACROSS THE CWA...ALTHOUGH A FEW
FLURRIES HAVE BEEN HANGING AROUND HERE AND THERE. ADJUSTED POPS TO
LOWER THEM IN THE FAR SOUTHEAST AND PUT IN A FLURRY MENTION UNTIL
MID AFTERNOON. CLOUDS WILL CONTINUE TO HANG AROUND MOST OF THE
AREA EXCEPT IN THE FAR NORTHEAST WHERE LAKE OF THE WOODS MAY SEE A
BIT OF CLEARING THIS AFTERNOON.
UPDATE ISSUED AT 941 AM CST THU DEC 26 2013
MADE SOME TWEAKS UPWARD FOR POPS IN OUR SOUTHEASTERN COUNTIES
DURING THE NEXT FEW HOURS AS FARGO AND A FEW OTHER SITES HAVE BEEN
REPORTING 1SM VISIBILITY WITH SNOW. CONTINUE TO THINK THAT
ACCUMULATIONS WILL BE AROUND AN INCH OR SO. BUMPED UP TEMPS IN THE
SOUTHWESTERN COUNTIES A DEGREE OR SO AS THEY ARE ONLY A FEW
DEGREES BELOW WHAT WE HAD GOING FOR HIGHS.
UPDATE ISSUED AT 700 AM CST THU DEC 26 2013
WATER VAPOR LOOP INDICATED SHORT WAVE TROUGH EXTENDED FROM SOUTHEAST
MAN TO SD. RADAR INDICATED LIGHT SNOW WAS OCCURRING AHEAD OF SHORT
WAVE TROUGH. PRECIPITATION WAS MOVING TO THE SOUTHEAST ABOUT 35
KNOTS. NO CHANGES ON THIS UPDATE.
&&
.SHORT TERM...(TODAY THROUGH FRIDAY)
ISSUED AT 403 AM CST THU DEC 26 2013
UPPER LEVEL RIDGE OFF THE PACIFIC NORTHWEST COAST WILL FLATTEN AND
SHIFT INTO THE PLAINS BY FRI. JET STREAM TO THE THE WEST WILL SHIFT
NORTH OF THE AREA BY FRI. SHOULD MAKE FOR RELATIVELY MILD TEMPS FRI.
BUMP HIGH TEMPS UP COUPLE DEGREES FOR FRI. LOWERED LOW TEMPS COUPLE
DEGREES FOR FRI NIGHT WITH SHALLOW ARCTIC AIR EXPECTED TO MOVE OUT OF
CANADA.
WATER VAPOR LOOP INDICATED A SHORT WAVE TROUGH FROM SOUTHWEST MAN TO
WESTERN ND AND WAS MOVING SOUTHEAST ABOUT 55 KNOTS. LIGHT SNOW
PRECEDED TROUGH. PRECIP SHOULD MOVE ACROSS THE SOUTH AND WEST ZONES
MAINLY THIS MORNING. SHIFTED PRECIP TODAY MORE SOUTH AND WEST.
SOME WARM ADVECTION PRECIP WILL BE POSSIBLE LATE TONIGHT IN FAR
NORTHEAST ZONES. ADDED LIGHT PRECIP FAR NORTHEAST ZONES FOR LATE
TONIGHT.
ADDED PRECIP IN THE NORTH FOR FRI EVENING AND SHIFTED PRECIP A
LITTLE FARTHER SOUTH LATE FRI NIGHT.
.LONG TERM...(FRIDAY NIGHT THROUGH WEDNESDAY)
ISSUED AT 403 AM CST THU DEC 26 2013
SAT THROUGH WED...
IT LOOKS LIKE A HIGH IMPACT EVENT FOR SAT INTO SAT NIGHT...WITH
FALLING AND BLOWING SNOW BECOME AN ISSUE. A STRONG ARCTIC FRONT
WILL PUSH QUICKLY THROUGH THE AREA ON SATURDAY FROM NORTH TO SOUTH.
THERE WILL BE A BAND OF 1-2 INCHES OF SNOW FOR MAINLY THE NORTHERN
1/3 OF THE AREA...WITH STRONG WINDS DEVELOPING BEHIND THE COLD
FRONT. THERE WILL BE ABOUT 30-40KT TO MIX PER GFS/NAM...WITH THE
ECMWF EVEN STRONGER NEAR 40KT AT 925MB. THERE WILL BE INTENSE LOW
LEVEL CAA AND THIS WILL AID MOMENTUM TRANSPORT. IF MODEL PROGS PROVE
CORRECT...THERE WILL BE BLOWING SNOW FOR THE RED RIVER VALLEY AND
POINTS WEST...WITH LOW VISIBILITIES POSSIBLE WHEN FALLING SNOW
COMBINES WITH BLOWING SNOW. IN ADDITION...DANGEROUS WIND CHILLS
FALLING TO 40 BELOW WILL DEVELOP BY SATURDAY NIGHT. WE WILL BEGIN TO
HIGHLIGHT THIS WINTER WEATHER HAZARD WITH AN SPS THIS MORNING.
FOR SUNDAY THROUGH TUE...EXPECT DRY AND BITTERLY COLD TEMPS WITH
TEMPS WELL BELOW NORMAL...WITH ARCTIC AIR IN PLACE.
FOR WED...SOME MODERATION IN TEMPS ARE POSSIBLE WITH SOME SNOW IN
WEAK WAA REGIME.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z FRIDAY AFTERNOON)
ISSUED AT 1226 PM CST THU DEC 26 2013
THE LATEST RAP GUIDANCE IS SHOWING IFR CIGS OVER CNTRL ND GRADUALLY
SHIFTING EAST THROUGH THE NEXT 24 HOURS WHILE THE NAM/GFS MOS
GUIDANCE KEEPS CONDS MVFR. I WILL GO WITH THE RAP IDEA AS IT IS
VERIFYING WELL NOW...AND BRING IFR CIGS INTO THE VALLEY BY LATE AFTN
AND INTO TVF/BJI BY MIDNIGHT. THINGS SHOULD THEN START IMPROVING
ACROSS EASTERN ND BY MIDNIGHT...WITH LESS UNCERTAINTY WHEN IFR CIGS
WILL ERODE AT TVF/BJI...BUT DO EXPECT CLEARING BY END OF 18Z TAF
PERIOD.
&&
.FGF WATCHES/WARNINGS/ADVISORIES...
ND...NONE.
MN...NONE.
&&
$$
UPDATE...JR
SHORT TERM...HOPPES
LONG TERM...DK
AVIATION...SPEICHER
AREA FORECAST DISCUSSION
NWS BISMARCK ND
1203 PM CST THU DEC 26 2013
.UPDATE...
ISSUED AT 1203 PM CST THU DEC 26 2013
THE LATEST SURFACE ANALYSIS SHOWS THE WARM FRONT ROUGHLY LOCATED
FROM ROLLA TO CARRINGTON...INTO JAMESTOWN AND OAKES. RADAR AND
OBSERVATIONS SHOW THAT PRECIPITATION IN EAST CENTRAL HAS
ENDED. PER FOG/STRATUS LOOP...LOW CLOUDS STRETCH ALONG AND EAST
OF A LINE FROM TIOGA TO HAZEN...BISMARCK TO OAKES. THE HRRR KEEPS
THESE LOW CLOUDS IN EAST CENTRAL THROUGH THE AFTERNOON AND CONCUR
BASED ON LATEST LOOP. HAVE DELAYED ANY BREAKS IN THE OVERCAST
CONDITIONS UNTIL 00Z FRIDAY EAST CENTRAL. ON THE OUTER EDGES NEAR
THE LINE MENTIONED ABOVE...EXPECT SOME EROSION THROUGH THE
AFTERNOON. REST OF FORECAST REMAINS IN GOOD STANDING.
UPDATE ISSUED AT 855 AM CST THU DEC 26 2013
THE LATEST SATELLITE IMAGERY AND SURFACE OBSERVATIONS SHOW MAINLY
A CLEAR SKY IN THE WEST WITH SOME HIGH CLOUDS. THIS TRANSITIONS INTO
BKN/OVC CONDITIONS ALONG AND EAST OF WARM FRONT WHICH IS ACROSS
CENTRAL NORTH DAKOTA. PER LATEST NAM12/RAP13...THE WARM FRONT WILL
MAKE IT TO A RUGBY/JAMESTOWN LINE BY 18Z TODAY. LIGHT SNOW IS
TAPERING OFF IN EAST CENTRAL AND THE JAMES RIVER VALLEY PER LATEST
RADAR IMAGERY. WILL CONTINUE TO TREND THE POPS BELOW MEASURABLE
FROM WEST TO EAST THROUGH 18Z PER LATEST RAP13/NAM12 AND PREVIOUS
FORECAST.
LATEST 12Z NAM SHOWS WARM AIR ADVECTION CONTINUING THROUGH THE
SHORT TERM WHICH PEAKS FRIDAY AFTERNOON. TIME HEIGHT CROSS
SECTIONS SHOW WEAK OMEGA/VERTICAL MOTION/CLOUDS IN TANDEM WITH THE
THERMAL/WARM AIR ADVECTION. THE HRRR/HIGH RESOLUTION RAPID REFRESH
MODEL SKY/CEILING FORECAST SHOWS THE MAIN AREA OF LOW CLOUDS THIS
MORNING WILL REMAIN OVER EAST CENTRAL NORTH DAKOTA THROUGH THE
AFTERNOON. MINOR ADJUSTMENTS TO SKY AND TEMPERATURE GRIDS THIS
MORNING TO FIT BETTER WITH SATELLITE AND CURRENT OBSERVATIONS.
OTHERWISE THE PREVIOUS FORECAST IS ON TRACK.
UPDATE ISSUED AT 619 AM CST THU DEC 26 2013
SNOW WAS ENDING ACROSS THE WEST AND CENTRAL. THE SNOW AREA NOW BE
EAST OF A MINOT TO BISMARCK LINE FOR A FEW MORE HOURS THIS
MORNING...ENDING BEFORE NOON. TEMPERATURES WILL WARM INTO THE 30S
ACROSS THE SOUTHWEST AND 20S EAST. CURRENT FORECAST LOOKS ON TRACK.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 345 AM CST THU DEC 26 2013
A WARM FRONT EXTENDED FROM A LOW OVER NORTHERN ALBERTA
SOUTHEASTWARD INTO SOUTHERN SASKATCHEWAN TO THE WESTERN DAKOTAS.
THIS TROUGH IS EXPECTED TO MOVE EAST THROUGH THE DEVILS LAKE AND
JAMES RIVER VALLEY AROUND SUNRISE. UPPER LEVEL SHORTWAVE ENERGY
MOVING SOUTHEAST...COMBINED WITH LOW LEVEL CONVERGENCE...WILL
SUPPORT LIFTING ALONG THE SURFACE TROUGH. LIGHT SNOW HAD ENDED AT
WILLISTON AND DICKINSON. IT APPEARS THE SNOW BAND WAS IN A
NORTH-SOUTH ORIENTED FASHION ROUGHLY 50 MILES WIDE. THIS AREA OF
SNOW HAD REACHED MINOT BY AROUND 230 AM CST AND SHOULD CONTINUE
EASTWARD. EXPECT LIGHT SNOW TO REACH THE BISMARCK AREA BEFORE 4 AM
CST...AND THEN REACHING THE JAMES RIVER VALLEY AREA BEFORE SUNRISE.
MILD PACIFIC AIR BEHIND THE WARM FRONT WILL RESULT IN WEST/SOUTHWEST
WINDS TODAY...AND ANOTHER RELATIVELY WARM DAY IN STORE. LOOKING AT
HIGHS FROM THE UPPER 30S SOUTHWEST TO THE MID/UPPER 20S IN THE
TURTLE MOUNTAINS AND JAMES VALLEY AREAS.
ANOTHER MILD NIGHT TONIGHT WITH ANOTHER CLIPPER-TYPE LOW MOVING
SOUTHEAST ACROSS SOUTHERN SASKATCHEWAN...KEEPING THE SURFACE
PRESSURE GRADIENT TIGHT ENOUGH FOR WEST/SOUTHWEST WINDS TO REMAIN
AROUND 10 TO 15 MPH OR SO. LOOKING AT LOWS TONIGHT FROM THE TEENS
CENTRAL TO 20S WEST.
.LONG TERM...(FRIDAY THROUGH WEDNESDAY)
ISSUED AT 345 AM CST THU DEC 26 2013
CONCERNS IN THE EXTENDED PERIOD FOCUS ON A CLIPPER SYSTEM
ENTERING THE STATE SATURDAY MORNING AND BRINGING SNOW AND BLOWING
SNOW ALONG WITH COLD WIND CHILLS TO THE REGION. PRIOR TO
THIS...FRIDAY WILL BE UNUSUALLY MILD AS WARMER AIR MOVES OVER THE
REGION FROM A CHINOOK FLOW REGIME. THIS COULD PUT A BIT OF A CRUST
ON THE SNOW COVER...ESPECIALLY SOUTHWEST WHERE HIGHS MAY REACH THE
LOWER 40S ON FRIDAY. ECMWF/GFS MODELS NOW BRING THE ARCTIC FRONT IN
SOONER IN THE DAY SATURDAY THAN PREVIOUS RUNS. EXPECT FALLING
DAYTIME TEMPERATURES ACROSS THE REGION...BUT ESPECIALLY NORTH
SATURDAY...WITH WIND CHILLS REACHING POSSIBLE WIND CHILL CRITERIA
SATURDAY NIGHT...SUNDAY NIGHT AND AGAIN MONDAY NIGHT. SNOW
AMOUNTS OF 1 TO 2 INCHES APPEAR REASONABLE ACROSS THE NORTH AND
THIS WILL AID IN BLOWING SNOW. RAISED THE WINDS ABOUT 5 TO 10 MPH
OVER THE ALLBLEND GUIDANCE FOR SATURDAY ACROSS THE NORTH CENTRAL
AND EAST. THIS RAISED THE BLOWING SNOW POTENTIAL AND WILL ISSUE A
SPECIAL WEATHER STATEMENT FOR THE COMBINATION OF SNOW AND BLOWING
SNOW SATURDAY AND SATURDAY EVENING. THE COLD AIR SETTLES IN
THROUGH THE REMAINDER OF THE PERIOD...WITH A SMALL MODERATION IN
TEMPERATURES ACROSS THE SOUTHWEST BY WEDNESDAY.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z FRIDAY AFTERNOON)
ISSUED AT 1203 PM CST THU DEC 26 2013
MVFR CIGS EXPECTED FROM KMOT/KBIS/KJMS THROUGH LATE AFTERNOON WITH
KISN AND KDIK VFR. A RETURN TO VFR CONDITIONS WILL COMMENCE AT
KMOT/KBIS JUST PRIOR TO 00Z FRIDAY...AND AROUND 01Z FRIDAY AT
KJMS. THEREAFTER AND THROUGH THE REST OF THE TAF PERIOD...EXPECT
VFR CONDITIONS AT ALL AERODROMES WITH SCT/BKN MID LEVEL CLOUDS.
&&
.BIS WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...KS
SHORT TERM...JV
LONG TERM...WAA
AVIATION...KS
AREA FORECAST DISCUSSION
NWS CHARLESTON WV
725 AM EST THU DEC 26 2013
.SYNOPSIS...
WEAK COLD FRONT PUSHES EAST THIS MORNING. THEN HIGH PRESSURE
THROUGH SATURDAY. LOW PRESSURE MOVES UP THE EAST COAST
SUNDAY...WITH A COLD FRONT FOR SUNDAY NIGHT.
&&
.NEAR TERM /THROUGH TONIGHT/...
SENT A QUICK UPDATE ON WINDS AS SFC OBS AND RUC13 ISENTROPIC SFC
AT 275K SUGGEST 25 TO 30 KNOTS CLOSE TO THE GROUND INCREASING AND
VEERING FROM SOUTH TO WEST BY 15Z. REST OF FORECAST REMAINS
REPRESENTATIVE.
&&
.SHORT TERM /FRIDAY THROUGH SUNDAY/...
HIGH PRESSURE IN CONTROL TO START THE SHORT TERM PERIOD WITH A GOOD
AMOUNT OF SUNSHINE DURING THE DAY BUT ALSO DECENT RADIATIONAL
COOLING AT NIGHT. INCREASED POPS PRETTY SIGNIFICANTLY SATURDAY NIGHT
INTO SUNDAY AS LOW PRESSURE SLIDES ACROSS THE SOUTHEAST US. GFS AND
ECMWF IN DECENT AGREEMENT ON THIS SYSTEM...WHILE NAM HAS A MUCH
TIGHTER GRADIENT ON THE MOISTURE KEEPING MOST OF THE CWA DRY.
TRENDED TOWARDS A GFS/ECMWF BLEND...WHICH AGREES WITH WPC GUIDANCE
AS WELL. WHILE CONFIDENCE IS RATHER LOW IN P-TYPE FORECAST...HAVE
TEMPERATURE PROFILE WARM ENOUGH FOR MOSTLY RAIN...BUT WITH SOME
WINTRY MIX EARLY SUNDAY MORNING.
USED A BLEND OF MAV/MET MOS FOR HIGHS AND LOWS THROUGH
SATURDAY...THEN TRANSITIONED TO BLENDING IN CONSENSUS GUIDANCE.
&&
.LONG TERM /SUNDAY NIGHT THROUGH WEDNESDAY/...
MAIN STORY THIS PERIOD IS A SOUTHERN STREAM SYSTEM NOW PROGGED TO
IMPACT THE AREA WITH PRECIPITATION...MAINLY IN SUNDAY.
CONFLUENCE ZONE BETWEEN NORTHERN AND SOUTHERN STREAMS IS NOW SHOWN
TO GET N OF THE FCST AREA...EVEN N OF THE MASON-DIXON LINE...SAT
NT. THIS ALLOWS MOISTURE TO WORK NWWD INTO THE FCST AREA SAT NT.
SFC LOW IS PROGGED TO TRACK NEWD TO COASTAL S CAROLINA SUN MORNING
AND THEN OFF THE MIDDLE ATLANTIC SEABOARD SUN AFTERNOON BEFORE
RACING OUT OVER THE OPEN ATLANTIC SUN NT.
WITH NO COLD AIR ASSOCIATED WITH THIS SYSTEM...OR FCST TO INTERACT
WITH THIS SYSTEM AT ANY POINT...PRECIPITATION TYPE SHOULD BE MAINLY
RAIN. POCKETS OF FREEZING RAIN BRIEFLY IN THE DEEPER HOLLOWS IS NOT
OUT OF THE QUESTION AS IT RADIATES SAT EVENING. HAVE BRIEF SNOW IN
THE NORTHERN MOUNTAINS AT THE START EARLY SUNDAY MORNING FOR NOW.
NORTHERN STREAM DRIVEN COLD FRONT CROSSES SUN NT...ITS MAIN IMPACT
BEING UPSLOPE SNOW SHOWERS IN ITS WAKE INTO MON NT.
A BROAD L/W TROUGH AMPLIFIES OVER CENTRAL AND EASTERN NORTH AMERICA
EARLY NEXT WEEK...AS A RIDGE AMPLIFIES UPON MOVING ONSHORE ON THE W
COAST. THIS BRINGS ABOUT A CHILLY...MAINLY DRY INTERLUDE FOR
MIDWEEK. ANOTHER COLD FRONT IS DRIVEN SWD THROUGH THE AREA DURING
THAT TIME...BUT WITH LIMITED MOISTURE WITH IT AND EVEN LIMITED
UPSLOPE IN ITS WAKE...HAVE DRY FCST AT THIS TIME.
FURTHER AMPLIFICATION OF THE L/W TROUGH ADVERTISED VIA THE OVERNIGHT
GFS AND ECMWF RUNS LEADING TO A MAJOR ARCTIC OUTBREAK IN THE E LATE
NEXT WEEK...HAS DISAPPEARED FROM BOTH MODELS FOR THE 12Z CYCLE.
YET...IT IS NOT OUT OF THE QUESTION AMPLIFICATION TO A SIMILAR
DEGREE PANS OUT SOMETIME DURING THE FIRST WEEK OR TWO OF THE NEW
YEAR...2014.
USED BIAS CORRECTED BLEND OF GUIDANCE TO RAISE HIGHS A BIT
SUN...EXCEPT A BIT LOWER UNDER CLOUDS AND RAIN IN THE E. NO CHANGES
TO HIGHS MON WITH VALUES ALREADY NEAR THE CENTER OF THE GUIDANCE
ENVELOPES. RAISED HIGHS TUE A BIT VIA HPC AND GFS-BASED GUIDANCE.
NO CHANGES TO HIGHS NEXT WED...STILL NEAR LOW END OF GUIDANCE. USED
CONSENSUS GUIDANCE FOR LOWS...BIAS CORRECTED EARLY ON AND STRAIGHT
UP DAY 6 AND 7 NTS. LOWS HIGHER THEN PREVIOUS SAT NT WITH SOUTHERN
STREAM SYSTEM COMING IN...AND OCCUR EARLY...ALSO HIGHER TUE NT WITH
LITTLE CHANGE OVER THE MIDDLE OF THE PERIOD WITH HPC ALSO BLENDED IN.
&&
.AVIATION /13Z THURSDAY THROUGH MONDAY/...
A BAND OF FLURRIES/SHSN WITH IFR CONDITIONS WILL PUSH EAST OF THE
REGION BY 15Z. HOWEVER...AN UPPER LEVEL TROUGH WILL CONTINUE THE
CHANCES FOR MVFR CONDITIONS IN FLURRIES/SHSN ACROSS SOUTHEAST OHIO
AND NORTHERN WEST VIRGINIA THROUGH 18Z. ACROSS THE REMAINDER OF
THE REGION...VFR CONDITIONS SHOULD PREVAIL.
THE TROUGH WILL THEN PUSH EAST WITH VFR CONDITIONS EXPECTED
REGION-WIDE BY 21Z.
FLOW TURNS MORE W THIS MORNING AND INCREASES WITH SOME 15 TO 25
KT GUSTS MOST SITES DURING MIXING HOURS...HIGHEST ACROSS N SITES.
THE FLOW SHOULD THEN BECOME LIGHT SOUTHERLY AFTER 00Z.
FORECAST CONFIDENCE AND ALTERNATE SCENARIOS THROUGH 12Z FRIDAY...
FORECAST CONFIDENCE: HIGH.
ALTERNATE SCENARIOS: IF SNOW SHOWER COVERAGE IS GREATER THAN
EXPECTED...CHANCES FOR OCCASIONAL IFR CONDITIONS AT NORTHERN TAF
SITES WILL BE INCREASED THROUGH 18Z.
EXPERIMENTAL TABLE OF FLIGHT CATEGORY OBJECTIVELY SHOWS CONSISTENCY
OF WFO FORECAST TO AVAILABLE MODEL INFORMATION:
H = HIGH: TAF CONSISTENT WITH ALL MODELS OR ALL BUT ONE MODEL.
M = MEDIUM: TAF HAS VARYING LEVEL OF CONSISTENCY WITH MODELS.
L = LOW: TAF INCONSISTENT WITH ALL MODELS OR ALL BUT ONE MODEL.
UTC 1HRLY 11 12 13 14 15 16 17 18 19 20 21 22
EST 1HRLY 06 07 08 09 10 11 12 13 14 15 16 17
CRW CONSISTENCY H H H H M H H H H H H H
HTS CONSISTENCY H H H H H H H H H H H H
BKW CONSISTENCY H H H H L H H H H H H H
EKN CONSISTENCY H L L L L L M M H H H H
PKB CONSISTENCY M L L L M H H H H H H H
CKB CONSISTENCY M L M L L M H H H H H H
AFTER 12Z FRIDAY...
NO WIDESPREAD IFR EXPECTED.
&&
.RLX WATCHES/WARNINGS/ADVISORIES...
WV...NONE.
OH...NONE.
KY...NONE.
VA...NONE.
&&
$$
SYNOPSIS...JSH/MZ
NEAR TERM...JSH/ARJ
SHORT TERM...MZ
LONG TERM...TRM
AVIATION...JSH
AREA FORECAST DISCUSSION
NWS GREENVILLE-SPARTANBURG SC
403 AM EST THU DEC 26 2013
.SYNOPSIS...
SHALLOW MOISTURE FROM THE GULF OF MEXICO WILL BRUSH THE SOUTHEAST
PIEDMONT TODAY. DRY HIGH PRESSURE WILL THEN BUILD OVER THE REGION
THROUGH FRIDAY NIGHT. EXPECT LOW PRESSURE TO TRACK FROM THE GULF OF
MEXICO SATURDAY TO THE CAROLINAS SUNDAY. A COLD FRONT WILL CROSS ON
MONDAY BRINGING COOLER WEATHER FOR TUESDAY.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 400 AM EST THURSDAY...PATCHY RAIN AND EVEN A COUPLE HEAVIER
SHOWERS CONTINUE TO AFFECT THE NE PIEDMONT OF SC AND THE SRN NC
PIEDMONT THIS MORNING. A FEW AREAS OF FREEZING RAIN ARE STILL
POSSIBLE TO THE NORTH AND WEST OF CHARLOTTE. WE HAVE ISSUED A
SPECIAL WEATHER STATEMENT TO ACCOUNT FOR THIS. FORTUNATELY...THE
HEAVIER SHOWERS LOOK TO BE DEVELOPING FATHER TO THE SOUTH...AND THEY
SHOULD MAINLY AFFECT UNION...YORK AND CHESTER COUNTIES WHERE
TEMPERATURES ARE ABOVE FREEZING. HIGH CLOUDS WILL ALSO COVER THE SRN
ZONES FOR A FEW MORE HOURS...KEEPING SKIES MOSTLY CLOUDY EVEN WHERE
THE LOW CLOUDS HAVE MOVED OUT.
AS OF 110 AM EST THURSDAY...WEAK RADAR RETURNS ARE SHOWING UP OVER
THE SOUTHEAST TIER OF COUNTIES. A COUPLE AWOS SITES DOWN IN CAE/S
AREA HAVE REPORTED PCPN OVER THE PAST HOUR...SO THE PCPN DOES APPEAR
TO BE REACHING THE GROUND. THE THINKING IS THAT THE PCPN WON/T MAKE
MUCH MORE PROGRESS TO THE NORTHWEST...BUT THAT IT WILL EXPAND INTO
THE SRN NC PIEDMONT. THIS IS WHAT OUR WORKSTATION WRF MODEL IS
SHOWING. SO FAR TEMPERATURES HAVE SHOWN A TENDENCY TO WARM AS CLOUD
COVER AND LIGHT PCPN HAS MOVED IN RIGHT. RIGHT NOW NO PCPN IS
FALLING WHERE THE TEMPERATURE IS AT OR BELOW FREEZING. FOR THE MOST
PART I THINK THAT WILL BE THE TREND OVER THE NEXT SEVERAL HOURS.
STILL...THERE COULD BE ONE OR TWO PATCHES OF BRIEF FREEZING RAIN
ACROSS THE I-77 CORRIDOR. FOR NOW I JUST HAVE A TINY AMOUNT OF
FREEZING RAIN IN THIS AREA IN THE GRIDS...CERTAINLY NOT ENOUGH TO
GET EXCITED ABOUT. BUT WE WILL WATCH THIS CLOSELY AS IT WILL ONLY
TAKE A LIGHT GLAZE TO MAKE BRIDGES AND ELEVATED SFC/S ICY
CONSIDERING HOW COOL IT/S BEEN THE PAST COUPLE DAYS.
SKIES SHOULD CLEAR BY MID-MORNING...FOLLOWED BY A CLEAR AND
SEASONABLY COOL DAY. HIGH PRESSURE WILL BRING CLEAR AND COOL
CONDITIONS TONIGHT.
&&
.SHORT TERM /FRIDAY THROUGH SUNDAY/...
AT 230 AM EST THURSDAY...ON FRIDAY MORNING A POSITIVELY TILTED UPPER
TROUGH WILL EXTEND FROM HUDSON BAY TO NORTHERN MEXICO. THE NORTHERN
AND SOUTHERN PORTIONS OF THE TROUGH GO OUT OF PHASE BY SATURDAY
MORNING...WITH THE NORTHERN TROUGH DEAMPLIFYING OVER CANADA...AND AN
UPPER LOW CLOSES OFF OVER TX OR OK. THE UPPER LOW FILLS AND
PROGRESSES ON SATURDAY...WHILE A SOUTHERN STREAM RIDGE DOWNSTREAM
AMPLIFIES OVER THE SOUTHEAST. THE SHORTWAVE REMAINS OF THE LOW THEN
CROSS THE SOUTHERN APPALACHIANS ON SUNDAY.
HIGH PRESSURE WILL REMAIN OVER CAROLINAS AND GA FROM FRIDAY THROUGH
SATURDAY...WHILE A STATIONARY FRONT LINGER ACROSS S FL AND THE
SOUTHERN GULF OF MEXICO. INITIALLY...CIRRUS SPILLING EAST OVER THE
UPPER RIDGE WILL BE THE ONLY CLOUD COVER. ON SATURDAY...THE GULF
FRONT WILL LIFT NORTH...AND ISENTROPIC UPGLIDE WILL SET UP OVER THE
BOUNDARY. LOW CLOUDS AND PRECIPITATION SHOULD CROSS THE UPPER
SAVANNAH RIVER VALLEY ON SATURDAY AFTERNOON...SPREADING ACROSS THE
ENTIRE AREA ON SATURDAY EVENING. THERMAL PROFILES AND THICKNESS
VALUES SOLIDLY SUPPORT LIQUID PRECIPITATION SATURDAY NIGHT AND
SUNDAY MORNING...ALTHOUGH SOME MOUNTAIN SURFACE TEMPERATURES COULD
BE JUST A FEW DEGREES ABOVE FREEZING BY SUNDAY MORNING.
WITH THE WARM FRONT NEVER REACHING THIS FAR NORTH...LOW LEVEL FLOW
IS EXPECTED TO BACK FROM SOUTHEASTERLY TO NORTHEASTERLY AS IN SITU
COLD AIR DAMMING SETS UP...SHIFTING THE BETTER UPSLOPE FLOW
COMPONENT FROM THE SOUTH FACING BLUE RIDGE TO THE EAST FACING BLUE
RIDGE.
A SURFACE WAVE WILL DRAG A COLD FRONT ACROSS THE AREA AROUND MIDDAY
SUNDAY...FOLLOWED BY DRYING IN THE LEE OF THE MOUNTAINS. MOIST NW
FLOW INTO THE NC MOUNTAINS BORDERING TN WILL KEEP PRECIPITATION
GOING THROUGH LATE AFTERNOON THERE. A LACK OF ICE NUCLEATION SUNDAY
AFTERNOON WILL NOT SUPPORT A CHANGE OVER TO SNOW SHOWERS AT
HIGH ELEVATIONS.
TEMPERATURES WILL EXHIBIT A DECREASING DIURNAL TEMPERATURE RANGE AS
CLOUD COVER AND MOISTURE INCREASE...LIMITING COOLING AND HEATING.
&&
.LONG TERM /SUNDAY NIGHT THROUGH WEDNESDAY/...
AS OF 210 AM THURSDAY...LOW PRESSURE MOVES OFF THE MID ATLANTIC
COAST SUNDAY NIGHT AS A COLD FRONT MOVES OVER WESTERN TENNESSEE AND
PROGRESSES EAST ON MONDAY. UPSLOPE FLOW UP AGAINST THE TN AND NC
BORDER WILL LIKELY NOT PRODUCE MUCH IN THE WAY OF SHOWERS AS
MOISTURE IS LIMITED. THERE ARE DIFFERENCES IN THE TIMING AND AMOUNT
OF MTN SNOW SHOWERS FROM LATE SUNDAY NIGHT TO MONDAY NIGHT BETWEEN
THE GFS AND ECMWF. GFS HAS VERY BRIEF WRAP AROUND MOISTURE EARLY
SUNDAY NIGHT FOR THE NC MTNS ALONG THE TN BORDER THEN BRING FRONTAL
MOISTURE UP AGAINST THE MTNS LATE MONDAY AND MONDAY NIGHT. THE ECMWF
HAS MORE SIGNIFICANT WRAP AROUND MOISTURE EARLY SUNDAY NIGHT AND
GRADUALLY DECREASES THAT TIL DISSIPATED EARLY MONDAY...THEN NOTHING
THROUGH MID WEEK. COMPROMISED AND ALSO MAINTAINS SOME OF PREVIOUS
FORECAST THINKING AS THIS COULD CHANGE AGAIN WITH THE NEXT MODEL
RUN. BEHIND THE COLD FRONT THE GFS A MUCH DEEPER THICKNESS TROUGH
COMPARED TO THE ECMWF.
WEATHER BECOMES DRIER AND A BIT COOLER TUESDAY UNDER THE THICKNESS
TROUGH PASSING WEST TO EAST. WEAK SURFACE HIGH PRESSURE WILL REMAIN
OVER THE WESTERN CAROLINAS TUESDAY AND WEDNESDAY. EXPECT SOME FORM
OF A NEW LOW PRESSURE DEVELOPING NEAR TEXAS LATE WEDNESDAY AND
WEDNESDAY NIGHT...THEN MOVING TOWARD OUR REGION. CLOUDS WILL
INCREASE WEDNESDAY NIGHT BUT ALL PRECIP WILL ARRIVE AFTER OUR
CURRENT DAY 7.
TEMPERATURES WILL BE A LITTLE BELOW NORMAL THROUGH THE PERIOD WITH
THE COOLEST DAY ON TUESDAY.
&&
.AVIATION /09Z THURSDAY THROUGH MONDAY/...
AT KCLT...THE LATEST NAM SOUNDINGS ARE MUCH DRIER AT THE AIRFIELD.
IN FACT...THEY ARE TOO DRY BASED ON THE CLOUD DECK WHICH HAS
RECENTLY MOVED IN. THE RAP SOUNDINGS ARE DOING A BETTER JOB...BUT
EVEN THEN THE MOISTURE IS QUITE SHALLOW. SOME WEAK RADAR RETURNS ARE
SHOWING UP NOW ABOUT 30 NM SOUTH OF THE AIRFIELD. BUT THE AIRMASS
DRIES OUT QUICKLY THE FARTHER NORTH ONE GOES. I THINK ANY PCPN WILL
MISS THE AIRFIELD TO THE SOUTH...BUT I DID ADD A VCSH. THERE IS
STILL A SMALL CHANCE OF A BRIEF PERIOD OF FREEZING RAIN...THOUGH I
SUSPECT THE SFC TEMPERATURES WILL STAY A COUPLE DEGREES ABOVE
FREEZING UNDER THE CLOUD DECK. AS FOR CIG HEIGHTS...THEY SHOULD FALL
TO AROUND 4KFT IN A COUPLE HOURS...THEN CLEAR BY 12-13 UTC. LIGHT
WINDS WILL TURN OUT OF THE NORTH AROUND NOON AS A WEAK COLD FRONT
CROSSES THE REGION.
ELSEWHERE...VFR CIGS WILL CONTINUE OVER THE UPSTATE FOR SEVERAL MORE
HOURS. ANY PCPN SHOULD STAY SOUTHEAST OF THE UPSTATE AIRFIELDS. NOT
EXPECTING THE LOWER VFR CIGS TO MAKE IT INTO KHKY OR KAVL. THE CIGS
WILL CLEAR FROM WEST TO EAST BETWEEN 10-12 UTC. WINDS WILL BE
LIGHT...BUT WILL TURN OUT OF THE NORTH LATER TODAY AS A WEAK COLD
FRONT CROSSES THE REGION.
OUTLOOK...VFR CONDITIONS ARE EXPECTED TO PERSIST THROUGH THE WEEK.
LOW PRESSURE WILL DEVELOP OVER THE NORTHERN GULF ON SATURDAY...
CROSSING THE WESTERN CAROLINAS ON SUNDAY. THIS WILL SPREAD RAIN AND
RESTRICTIVE CIGS AND VSBYS ACROSS THE REGION SATURDAY NIGHT AND
SUNDAY.
CONFIDENCE TABLE...
09-15Z 15-21Z 21-03Z 03-09Z
KCLT HIGH 100% HIGH 100% HIGH 100% HIGH 100%
KGSP HIGH 100% HIGH 100% HIGH 100% HIGH 100%
KAVL HIGH 100% HIGH 100% HIGH 100% HIGH 100%
KHKY HIGH 100% HIGH 100% HIGH 100% HIGH 100%
KGMU HIGH 100% HIGH 100% HIGH 100% HIGH 100%
KAND MED 79% HIGH 100% HIGH 100% HIGH 100%
THE PERCENTAGE REFLECTS THE NUMBER OF GUIDANCE MEMBERS AGREEING
WITH THE SCHEDULED TAF ISSUANCE FLIGHT RULE CATEGORY. COMPLETE
HOURLY EXPERIMENTAL AVIATION FORECAST CONSISTENCY TABLES AND ENSEMBLE
FORECASTS ARE AVAILABLE AT THE FOLLOWING LINK: (MUST BE LOWER CASE)
WWW.WEATHER.GOV/GSP/AVIATION_TABLES
&&
.GSP WATCHES/WARNINGS/ADVISORIES...
GA...NONE.
NC...NONE.
SC...NONE.
&&
$$
SYNOPSIS...DEO
NEAR TERM...MCAVOY
SHORT TERM...JAT
LONG TERM...DEO
AVIATION...MCAVOY
AREA FORECAST DISCUSSION
NWS GREENVILLE-SPARTANBURG SC
256 AM EST THU DEC 26 2013
.SYNOPSIS...
SHALLOW MOISTURE FROM THE GULF OF MEXICO WILL BRUSH THE SOUTHEAST
PIEDMONT TODAY. DRY HIGH PRESSURE WILL THEN BUILD OVER THE REGION
THROUGH FRIDAY NIGHT. EXPECT LOW PRESSURE TO TRACK FROM THE GULF OF
MEXICO SATURDAY TO THE CAROLINAS SUNDAY. A COLD FRONT WILL CROSS ON
MONDAY BRINGING COOLER WEATHER FOR TUESDAY.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 110 AM EST THURSDAY...WEAK RADAR RETURNS ARE SHOWING UP OVER
THE SOUTHEAST TIER OF COUNTIES. A COUPLE AWOS SITES DOWN IN CAE/S
AREA HAVE REPORTED PCPN OVER THE PAST HOUR...SO THE PCPN DOES APPEAR
TO BE REACHING THE GROUND. THE THINKING IS THAT THE PCPN WON/T MAKE
MUCH MORE PROGRESS TO THE NORTHWEST...BUT THAT IT WILL EXPAND INTO
THE SRN NC PIEDMONT. THIS IS WHAT OUR WORKSTATION WRF MODEL IS
SHOWING. SO FAR TEMPERATURES HAVE SHOWN A TENDENCY TO WARM AS CLOUD
COVER AND LIGHT PCPN HAS MOVED IN RIGHT. RIGHT NOW NO PCPN IS
FALLING WHERE THE TEMPERATURE IS AT OR BELOW FREEZING. FOR THE MOST
PART I THINK THAT WILL BE THE TREND OVER THE NEXT SEVERAL HOURS.
STILL...THERE COULD BE ONE OR TWO PATCHES OF BRIEF FREEZING RAIN
ACROSS THE I-77 CORRIDOR. FOR NOW I JUST HAVE A TINY AMOUNT OF
FREEZING RAIN IN THIS AREA IN THE GRIDS...CERTAINLY NOT ENOUGH TO
GET EXCITED ABOUT. BUT WE WILL WATCH THIS CLOSELY AS IT WILL ONLY
TAKE A LIGHT GLAZE TO MAKE BRIDGES AND ELEVATED SFC/S ICY
CONSIDERING HOW COOL IT/S BEEN THE PAST COUPLE DAYS.
SKIES SHOULD CLEAR BY MID-MORNING...FOLLOWED BY A CLEAR AND
SEASONABLY COOL DAY. HIGH PRESSURE WILL BRING CLEAR AND COOL
CONDITIONS TONIGHT.
&&
.SHORT TERM /FRIDAY THROUGH SUNDAY/...
AT 230 AM EST THURSDAY...ON FRIDAY MORNING A POSITIVELY TILTED UPPER
TROUGH WILL EXTEND FROM HUDSON BAY TO NORTHERN MEXICO. THE NORTHERN
AND SOUTHERN PORTIONS OF THE TROUGH GO OUT OF PHASE BY SATURDAY
MORNING...WITH THE NORTHERN TROUGH DEAMPLIFYING OVER CANADA...AND AN
UPPER LOW CLOSES OFF OVER TX OR OK. THE UPPER LOW FILLS AND
PROGRESSES ON SATURDAY...WHILE A SOUTHERN STREAM RIDGE DOWNSTREAM
AMPLIFIES OVER THE SOUTHEAST. THE SHORTWAVE REMAINS OF THE LOW THEN
CROSS THE SOUTHERN APPALACHIANS ON SUNDAY.
HIGH PRESSURE WILL REMAIN OVER CAROLINAS AND GA FROM FRIDAY THROUGH
SATURDAY...WHILE A STATIONARY FRONT LINGER ACROSS S FL AND THE
SOUTHERN GULF OF MEXICO. INITIALLY...CIRRUS SPILLING EAST OVER THE
UPPER RIDGE WILL BE THE ONLY CLOUD COVER. ON SATURDAY...THE GULF
FRONT WILL LIFT NORTH...AND ISENTROPIC UPGLIDE WILL SET UP OVER THE
BOUNDARY. LOW CLOUDS AND PRECIPITATION SHOULD CROSS THE UPPER
SAVANNAH RIVER VALLEY ON SATURDAY AFTERNOON...SPREADING ACROSS THE
ENTIRE AREA ON SATURDAY EVENING. THERMAL PROFILES AND THICKNESS
VALUES SOLIDLY SUPPORT LIQUID PRECIPITATION SATURDAY NIGHT AND
SUNDAY MORNING...ALTHOUGH SOME MOUNTAIN SURFACE TEMPERATURES COULD
BE JUST A FEW DEGREES ABOVE FREEZING BY SUNDAY MORNING.
WITH THE WARM FRONT NEVER REACHING THIS FAR NORTH...LOW LEVEL FLOW
IS EXPECTED TO BACK FROM SOUTHEASTERLY TO NORTHEASTERLY AS IN SITU
COLD AIR DAMMING SETS UP...SHIFTING THE BETTER UPSLOPE FLOW
COMPONENT FROM THE SOUTH FACING BLUE RIDGE TO THE EAST FACING BLUE
RIDGE.
A SURFACE WAVE WILL DRAG A COLD FRONT ACROSS THE AREA AROUND MIDDAY
SUNDAY...FOLLOWED BY DRYING IN THE LEE OF THE MOUNTAINS. MOIST NW
FLOW INTO THE NC MOUNTAINS BORDERING TN WILL KEEP PRECIPITATION
GOING THROUGH LATE AFTERNOON THERE. A LACK OF ICE NUCLEATION SUNDAY
AFTERNOON WILL NOT SUPPORT A CHANGE OVER TO SNOW SHOWERS AT
HIGH ELEVATIONS.
TEMPERATURES WILL EXHIBIT A DECREASING DIURNAL TEMPERATURE RANGE AS
CLOUD COVER AND MOISTURE INCREASE...LIMITING COOLING AND HEATING.
&&
.LONG TERM /SUNDAY NIGHT THROUGH WEDNESDAY/...
AS OF 210 AM THURSDAY...LOW PRESSURE MOVES OFF THE MID ATLANTIC
COAST SUNDAY NIGHT AS A COLD FRONT MOVES OVER WESTERN TENNESSEE AND
PROGRESSES EAST ON MONDAY. UPSLOPE FLOW UP AGAINST THE TN AND NC
BORDER WILL LIKELY NOT PRODUCE MUCH IN THE WAY OF SHOWERS AS
MOISTURE IS LIMITED. THERE ARE DIFFERENCES IN THE TIMING AND AMOUNT
OF MTN SNOW SHOWERS FROM LATE SUNDAY NIGHT TO MONDAY NIGHT BETWEEN
THE GFS AND ECMWF. GFS HAS VERY BRIEF WRAP AROUND MOISTURE EARLY
SUNDAY NIGHT FOR THE NC MTNS ALONG THE TN BORDER THEN BRING FRONTAL
MOISTURE UP AGAINST THE MTNS LATE MONDAY AND MONDAY NIGHT. THE ECMWF
HAS MORE SIGNIFICANT WRAP AROUND MOISTURE EARLY SUNDAY NIGHT AND
GRADUALLY DECREASES THAT TIL DISSIPATED EARLY MONDAY...THEN NOTHING
THROUGH MID WEEK. COMPROMISED AND ALSO MAINTAINS SOME OF PREVIOUS
FORECAST THINKING AS THIS COULD CHANGE AGAIN WITH THE NEXT MODEL
RUN. BEHIND THE COLD FRONT THE GFS A MUCH DEEPER THICKNESS TROUGH
COMPARED TO THE ECMWF.
WEATHER BECOMES DRIER AND A BIT COOLER TUESDAY UNDER THE THICKNESS
TROUGH PASSING WEST TO EAST. WEAK SURFACE HIGH PRESSURE WILL REMAIN
OVER THE WESTERN CAROLINAS TUESDAY AND WEDNESDAY. EXPECT SOME FORM
OF A NEW LOW PRESSURE DEVELOPING NEAR TEXAS LATE WEDNESDAY AND
WEDNESDAY NIGHT...THEN MOVING TOWARD OUR REGION. CLOUDS WILL
INCREASE WEDNESDAY NIGHT BUT ALL PRECIP WILL ARRIVE AFTER OUR
CURRENT DAY 7.
TEMPERATURES WILL BE A LITTLE BELOW NORMAL THROUGH THE PERIOD WITH
THE COOLEST DAY ON TUESDAY.
&&
.AVIATION /08Z THURSDAY THROUGH MONDAY/...
AT KCLT...THE LATEST NAM SOUNDINGS ARE MUCH DRIER AT THE AIRFIELD.
IN FACT...THEY ARE TOO DRY BASED ON THE CLOUD DECK WHICH HAS
RECENTLY MOVED IN. THE RAP SOUNDINGS ARE DOING A BETTER JOB...BUT
EVEN THEN THE MOISTURE IS QUITE SHALLOW. SOME WEAK RADAR RETURNS ARE
SHOWING UP NOW ABOUT 30 NM SOUTH OF THE AIRFIELD. BUT THE AIRMASS
DRIES OUT QUICKLY THE FARTHER NORTH ONE GOES. I THINK ANY PCPN WILL
MISS THE AIRFIELD TO THE SOUTH...BUT I DID ADD A VCSH. THERE IS
STILL A SMALL CHANCE OF A BRIEF PERIOD OF FREEZING RAIN...THOUGH I
SUSPECT THE SFC TEMPERATURES WILL STAY A COUPLE DEGREES ABOVE
FREEZING UNDER THE CLOUD DECK. AS FOR CIG HEIGHTS...THEY SHOULD FALL
TO AROUND 4KFT IN A COUPLE HOURS...THEN CLEAR BY 12-13 UTC. LIGHT
WINDS WILL TURN OUT OF THE NORTH AROUND NOON AS A WEAK COLD FRONT
CROSSES THE REGION.
ELSEWHERE...VFR CIGS WILL CONTINUE OVER THE UPSTATE FOR SEVERAL MORE
HOURS. ANY PCPN SHOULD STAY SOUTHEAST OF THE UPSTATE AIRFIELDS. NOT
EXPECTING THE LOWER VFR CIGS TO MAKE IT INTO KHKY OR KAVL. THE CIGS
WILL CLEAR FROM WEST TO EAST BETWEEN 10-12 UTC. WINDS WILL BE
LIGHT...BUT WILL TURN OUT OF THE NORTH LATER TODAY AS A WEAK COLD
FRONT CROSSES THE REGION.
OUTLOOK...VFR CONDITIONS ARE EXPECTED TO PERSIST THROUGH THE WEEK.
LOW PRESSURE WILL DEVELOP OVER THE NORTHERN GULF ON SATURDAY...
CROSSING THE WESTERN CAROLINAS ON SUNDAY. THIS WILL SPREAD RAIN AND
RESTRICTIVE CIGS AND VSBYS ACROSS THE REGION SATURDAY NIGHT AND
SUNDAY.
CONFIDENCE TABLE...
08-14Z 14-20Z 20-02Z 02-08Z
KCLT HIGH 100% HIGH 100% HIGH 100% HIGH 100%
KGSP HIGH 100% HIGH 100% HIGH 100% HIGH 100%
KAVL HIGH 100% HIGH 100% HIGH 100% HIGH 100%
KHKY HIGH 100% HIGH 100% HIGH 100% HIGH 100%
KGMU HIGH 100% HIGH 100% HIGH 100% HIGH 100%
KAND MED 71% HIGH 100% HIGH 100% HIGH 100%
THE PERCENTAGE REFLECTS THE NUMBER OF GUIDANCE MEMBERS AGREEING
WITH THE SCHEDULED TAF ISSUANCE FLIGHT RULE CATEGORY. COMPLETE
HOURLY EXPERIMENTAL AVIATION FORECAST CONSISTENCY TABLES AND ENSEMBLE
FORECASTS ARE AVAILABLE AT THE FOLLOWING LINK: (MUST BE LOWER CASE)
WWW.WEATHER.GOV/GSP/AVIATION_TABLES
&&
.GSP WATCHES/WARNINGS/ADVISORIES...
GA...NONE.
NC...NONE.
SC...NONE.
&&
$$
SYNOPSIS...DEO
NEAR TERM...MCAVOY
SHORT TERM...JAT
LONG TERM...DEO
AVIATION...MCAVOY
AREA FORECAST DISCUSSION
NWS GREENVILLE-SPARTANBURG SC
111 AM EST THU DEC 26 2013
.SYNOPSIS...
SHALLOW MOISTURE FROM THE GULF OF MEXICO WILL BRUSH THE SOUTHEAST
PIEDMONT TODAY. DRY HIGH PRESSURE WILL THEN BUILD OVER THE REGION
THROUGH FRIDAY NIGHT. EXPECT LOW PRESSURE TO TRACK FROM THE GULF OF
MEXICO SATURDAY TO THE CAROLINAS SUNDAY. A COLD FRONT WILL CROSS ON
MONDAY BRINGING COOLER WEATHER FOR TUESDAY.
&&
.NEAR TERM /THROUGH TODAY/...
AS OF 110 AM EST THURSDAY...WEAK RADAR RETURNS ARE SHOWING UP OVER
THE SOUTHEAST TIER OF COUNTIES. A COUPLE AWOS SITES DOWN IN CAE/S
AREA HAVE REPORTED PCPN OVER THE PAST HOUR...SO THE PCPN DOES APPEAR
TO BE REACHING THE GROUND. THE THINKING IS THAT THE PCPN WON/T MAKE
MUCH MORE PROGRESS TO THE NORTHWEST...BUT THAT IT WILL EXPAND INTO
THE SRN NC PIEDMONT. THIS IS WHAT OUR WORKSTATION WRF MODEL IS
SHOWING. SO FAR TEMPERATURES HAVE SHOWN A TENDENCY TO WARM AS CLOUD
COVER AND LIGHT PCPN HAS MOVED IN RIGHT. RIGHT NOW NO PCPN IS
FALLING WHERE THE TEMPERATURE IS AT OR BELOW FREEZING. FOR THE MOST
PART I THINK THAT WILL BE THE TREND OVER THE NEXT SEVERAL HOURS.
STILL...THERE COULD BE ONE OR TWO PATCHES OF BRIEF FREEZING RAIN
ACROSS THE I-77 CORRIDOR. FOR NOW I JUST HAVE A TINY AMOUNT OF
FREEZING RAIN IN THIS AREA IN THE GRIDS...CERTAINLY NOT ENOUGH TO
GET EXCITED ABOUT. BUT WE WILL WATCH THIS CLOSELY AS IT WILL ONLY
TAKE A LIGHT GLAZE TO MAKE BRIDGES AND ELEVATED SFC/S ICY
CONSIDERING HOW COOL IT/S BEEN THE PAST COUPLE DAYS.
SKIES SHOULD CLEAR BY MID-MORNING...FOLLOWED BY A CLEAR AND
SEASONABLY COOL DAY. HIGH PRESSURE WILL BRING CLEAR AND COOL
CONDITIONS TONIGHT.
&&
.SHORT TERM /TONIGHT THROUGH FRIDAY NIGHT/...
AS OF 1 PM EST WEDNESDAY...ZONAL FLOW THU NIGHT THROUGH FRI WILL
GIVE WAY TO WEAK UPPER RIDGING ACROSS THE SE FRI NIGHT AHEAD OF A
SRN STREAM SYSTEM DIGGING INTO TX. MEANWHILE...DRY SFC HIGH PRES
WILL REMAIN PARKED OVER THE REGION THROUGH THE PERIOD. ANY LOW TO
MID LEVEL MOISTURE RETURN FROM THE GULF OF MEXICO AHEAD OF THE SRN
SYSTEM SHOULD REMAIN S OF THE FORECAST AREA THROUGH FRI NIGHT.
TEMPERATURES WILL REMAIN SLIGHTLY BELOW CLIMO THROUGH THE PERIOD.
&&
.LONG TERM /SATURDAY THROUGH WEDNESDAY/...
AS OF MIDDAY WED...BROAD TROUGH ACRS THE NRN TIER OF THE CONUS OVER
THE WEEKEND WILL GRADUALLY AMPLIFY INTO EARLY NEXT WEEK...WITH A NRN
STREAM SHORTWAVE DIVING DOWN OUT OF THE PACIFIC NORTHWEST AND ANOTHER
SRN STREAM WAVE EJECTING OUT OF THE SRN PLAINS. THIS SRN WAVE HAS
BEEN SHOWN IN SOME FASHION BY THE GLOBAL MODELS FOR A FEW DAYS
NOW...AND NOW THEY ARE TRENDING TOWARD A MORE NRN TRACK OF THE WAVE.
CYCLOGENESIS THUS BEGINS OVER THE ERN GULF...WITH THE SFC LOW
CROSSING THE CAROLINAS THEN DEEPENING QUICKLY OFF THE ATLANTIC
COAST. THOUGH MINOR DETAILS STILL DIFFER BETWEEN THE MAJOR MODELS
AND GFS/CMC ENSEMBLE MEMBERS...THERE IS NOW AN INCREASINGLY STRONG
INDICATION OF A PERIOD OF WET WEATHER ACRS THE CWFA LATE SATURDAY
INTO SUNDAY.
CONSENSUS KEEPS THE TRACK OF THE SFC LOW NEAR THE COAST AND THUS OUR
CWFA STAYS ON THE COOL SIDE OF THE SYSTEM...PRECLUDING ANY MENTION OF
THUNDER. 12Z OPNL GFS IS THE WETTEST MODEL...GIVING THE PIEDMONT UP
TO 2 INCHES OF QPF. THIS SEEMS TO BE A RESULT OF ITS INDICATION OF A
SHARPER THERMAL GRADIENT AND TIGHTER SHORTWAVE. ENSEMBLES GENERALLY
KEEP THE MORE SIGNIFICANT QPF ON THE WARM SIDE OF THE SFC LOW CLOSER
TO THE COAST. HAVE RAISED POPS TO LIKELY SOUTH/EAST OF I-85 CORRIDOR
LATE SAT NIGHT AND SUN MRNG...WITH SOLID CHC ELSEWHERE. QPF IS IN THE
MIDDLE OF THE GUID RANGE...GENERALLY 3/4 TO 1 INCH. VERTICAL PROFILES
WITH STRONG WARM NOSE SUGGEST FREEZING RAIN WOULD RESULT IF ANY SFC
TEMPS WERE BELOW FREEZING...BUT GIVEN CLOUD COVER OVERNIGHT SAT NIGHT
I FAVORED WARMER TEMPS ABOVE FREEZING THROUGHOUT THE AREA.
WHILE THE PIEDMONT/FOOTHILLS DRY OUT LATE SUNDAY AS THE LOW DEPARTS
TO THE NORTHEAST...THE LONGWAVE TROUGH DEEPENS AS IT ABSORBS THE NRN
STREAM TROUGH. COLD FROPA THUS OCCURS IN THE MTNS MONDAY WITH ENOUGH
MOISTURE TO EXPECT A BRIEF NW FLOW SNOW EVENT AND BELOW NORMAL TEMPS
MON-TUE. GFS SUGGESTS LOW PRECIP CHANCES MON NIGHT EAST OF THE MTNS
AS WELL. TEMPS SHOULD BEGIN TO MODERATE BY WED WITH LOW POPS
RETURNING AS LOW PRESSURE CROSSES THE GREAT LAKES DRAGGING A WEAK
FRONT ACRS THE SOUTHEAST.
&&
.AVIATION /06Z THURSDAY THROUGH MONDAY/...
AT KCLT...THE LATEST NAM SOUNDINGS ARE MUCH DRIER AT THE AIRFIELD.
IN FACT...THEY ARE TOO DRY BASED ON THE CLOUD DECK WHICH HAS
RECENTLY MOVED IN. THE RAP SOUNDINGS ARE DOING A BETTER JOB...BUT
EVEN THEN THE MOISTURE IS QUITE SHALLOW. SOME WEAK RADAR RETURNS ARE
SHOWING UP NOW ABOUT 30 NM SOUTH OF THE AIRFIELD. BUT THE AIRMASS
DRIES OUT QUICKLY THE FARTHER NORTH ONE GOES. I THINK ANY PCPN WILL
MISS THE AIRFIELD TO THE SOUTH...BUT I DID ADD A VCSH. THERE IS
STILL A SMALL CHANCE OF A BRIEF PERIOD OF FREEZING RAIN...THOUGH I
SUSPECT THE SFC TEMPERATURES WILL STAY A COUPLE DEGREES ABOVE
FREEZING UNDER THE CLOUD DECK. AS FOR CIG HEIGHTS...THEY SHOULD FALL
TO AROUND 4KFT IN A COUPLE HOURS...THEN CLEAR BY 12-13 UTC. LIGHT
WINDS WILL TURN OUT OF THE NORTH AROUND NOON AS A WEAK COLD FRONT
CROSSES THE REGION.
ELSEWHERE...VFR CIGS WILL CONTINUE OVER THE UPSTATE FOR SEVERAL MORE
HOURS. ANY PCPN SHOULD STAY SOUTHEAST OF THE UPSTATE AIRFIELDS. NOT
EXPECTING THE LOWER VFR CIGS TO MAKE IT INTO KHKY OR KAVL. THE CIGS
WILL CLEAR FROM WEST TO EAST BETWEEN 10-12 UTC. WINDS WILL BE
LIGHT...BUT WILL TURN OUT OF THE NORTH LATER TODAY AS A WEAK COLD
FRONT CROSSES THE REGION.
OUTLOOK...VFR CONDITIONS ARE EXPECTED TO PERSIST THROUGH THE WEEK.
LOW PRESSURE WILL DEVELOP OVER THE NORTHERN GULF ON SATURDAY...
CROSSING THE WESTERN CAROLINAS ON SUNDAY. THIS WILL SPREAD RAIN AND
RESTRICTIVE CIGS AND VSBYS ACROSS THE REGION SATURDAY NIGHT AND
SUNDAY.
CONFIDENCE TABLE...
06-12Z 12-18Z 18-24Z 00-06Z
KCLT HIGH 100% HIGH 100% HIGH 100% HIGH 100%
KGSP HIGH 100% HIGH 100% HIGH 100% HIGH 100%
KAVL HIGH 100% HIGH 100% HIGH 100% HIGH 100%
KHKY HIGH 100% HIGH 100% HIGH 100% HIGH 100%
KGMU HIGH 100% HIGH 100% HIGH 100% HIGH 100%
KAND MED 72% HIGH 100% HIGH 100% HIGH 100%
THE PERCENTAGE REFLECTS THE NUMBER OF GUIDANCE MEMBERS AGREEING
WITH THE SCHEDULED TAF ISSUANCE FLIGHT RULE CATEGORY. COMPLETE
HOURLY EXPERIMENTAL AVIATION FORECAST CONSISTENCY TABLES AND ENSEMBLE
FORECASTS ARE AVAILABLE AT THE FOLLOWING LINK: (MUST BE LOWER CASE)
WWW.WEATHER.GOV/GSP/AVIATION_TABLES
&&
.GSP WATCHES/WARNINGS/ADVISORIES...
GA...NONE.
NC...NONE.
SC...NONE.
&&
$$
SYNOPSIS...HG
NEAR TERM...MCAVOY
SHORT TERM...HG
LONG TERM...WIMBERLEY
AVIATION...MCAVOY
AREA FORECAST DISCUSSION
NWS GREENVILLE-SPARTANBURG SC
1233 AM EST THU DEC 26 2013
.SYNOPSIS...
SHALLOW MOISTURE FROM THE GULF OF MEXICO WILL BRUSH THE SOUTHEAST
PIEDMONT TODAY. DRY HIGH PRESSURE WILL THEN BUILD OVER THE REGION
THROUGH FRIDAY NIGHT. EXPECT LOW PRESSURE TO TRACK FROM THE GULF OF
MEXICO SATURDAY TO THE CAROLINAS SUNDAY. A COLD FRONT WILL CROSS ON
MONDAY BRINGING COOLER WEATHER FOR TUESDAY.
&&
.NEAR TERM /THROUGH TODAY/...
AS OF MID EVENING...SATELLITE IMAGERY SHOWS THE BAND OF LOW CLOUDS
NOW ACROSS THE I-85 CORRIDOR...STILL MAKING SOME SLOW NWD PROGRESS.
NO PRECIP WAS SEEN ON AREA RADARS...BUT THIS WILL HAVE TO BE WATCHED
TOWARD DAYBREAK AS THE INTERIM MODEL GUIDANCE SHOWED SOME RESPONSE
RIGHT ON THE EDGE OF THE CLT METRO AREA. HOWEVER...THE NEW NAM KEEPS
THE PRECIP A BIT FURTHER EAST...SO HOPEFULLY THIS WILL NOT POSE A
PROBLEM. THE FCST WILL BE KEPT DRY FOR NOW...SO STILL NO CHANGES.
PREVIOUS DISCUSSION...
THE CENTER OF SFC HIGH PRESSURE MOVES OFF THE MID-ATLANTIC COAST
TONIGHT. RETURN FLOW MOISTURE AROUND THIS HIGH AND AHEAD OF A WEAK
COLD FRONT IS BRINGING LOW LEVEL MOISTURE NORTH TOWARD THE CWFA.
THIS MOISTURE MOVES INTO THE I-85 CORRIDOR TONIGHT. THERE IS SOME
ISENTROPIC LIFT WITH THIS MOISTURE AND SOME UPPER DIVERGENCE
ASSOCIATED WITH THE RIGHT ENTRANCE REGION OF A JET STREAK.
HOWEVER...THE SHORT WAVE ASSOCIATED WITH THIS SYSTEM IS WEAK AND
ORIENTED PARALLEL TO THE FLOW. ALSO...MOISTURE IS LIMITED TO THIS
ONE LAYER WITH ONLY CIRRUS ABOVE AND DRY NEAR SFC LEVELS. IN
FACT...THE LOWER LEVEL ISENTROPIC LIFT AND MOISTURE REMAIN WELL TO
OUR SOUTH. SINCE A GUIDANCE BLEND KEEPS OUR AREA DRY WITH ONLY
CLOUDS...HAVE GONE THIS DIRECTION WITH THE FCST. CANNOT RULE OUT
SOME SPRINKLES OR VERY LIGHT RAIN LATE TONIGHT OR EARLY THU MORN.
TEMPS WILL BE BELOW FREEZING BUT DO NOT EXPECT ANY FREEZING RAIN IF
PRECIP DOES DEVELOP AS IT WOULD BE VERY LIGHT NEAR TRACE AMOUNTS.
CLOUDS SHUD CLEAR THU MORN LEAVING A MOSTLY SUNNY AFTERNOON. LOWS
TONIGHT AS MUCH AS 5 DEGREES BELOW NORMAL WITH HIGHS THU NEAR TO
JUST BELOW NORMAL.
&&
.SHORT TERM /TONIGHT THROUGH FRIDAY NIGHT/...
AS OF 1 PM EST WEDNESDAY...ZONAL FLOW THU NIGHT THROUGH FRI WILL
GIVE WAY TO WEAK UPPER RIDGING ACROSS THE SE FRI NIGHT AHEAD OF A
SRN STREAM SYSTEM DIGGING INTO TX. MEANWHILE...DRY SFC HIGH PRES
WILL REMAIN PARKED OVER THE REGION THROUGH THE PERIOD. ANY LOW TO
MID LEVEL MOISTURE RETURN FROM THE GULF OF MEXICO AHEAD OF THE SRN
SYSTEM SHOULD REMAIN S OF THE FORECAST AREA THROUGH FRI NIGHT.
TEMPERATURES WILL REMAIN SLIGHTLY BELOW CLIMO THROUGH THE PERIOD.
&&
.LONG TERM /SATURDAY THROUGH WEDNESDAY/...
AS OF MIDDAY WED...BROAD TROUGH ACRS THE NRN TIER OF THE CONUS OVER
THE WEEKEND WILL GRADUALLY AMPLIFY INTO EARLY NEXT WEEK...WITH A NRN
STREAM SHORTWAVE DIVING DOWN OUT OF THE PACIFIC NORTHWEST AND ANOTHER
SRN STREAM WAVE EJECTING OUT OF THE SRN PLAINS. THIS SRN WAVE HAS
BEEN SHOWN IN SOME FASHION BY THE GLOBAL MODELS FOR A FEW DAYS
NOW...AND NOW THEY ARE TRENDING TOWARD A MORE NRN TRACK OF THE WAVE.
CYCLOGENESIS THUS BEGINS OVER THE ERN GULF...WITH THE SFC LOW
CROSSING THE CAROLINAS THEN DEEPENING QUICKLY OFF THE ATLANTIC
COAST. THOUGH MINOR DETAILS STILL DIFFER BETWEEN THE MAJOR MODELS
AND GFS/CMC ENSEMBLE MEMBERS...THERE IS NOW AN INCREASINGLY STRONG
INDICATION OF A PERIOD OF WET WEATHER ACRS THE CWFA LATE SATURDAY
INTO SUNDAY.
CONSENSUS KEEPS THE TRACK OF THE SFC LOW NEAR THE COAST AND THUS OUR
CWFA STAYS ON THE COOL SIDE OF THE SYSTEM...PRECLUDING ANY MENTION OF
THUNDER. 12Z OPNL GFS IS THE WETTEST MODEL...GIVING THE PIEDMONT UP
TO 2 INCHES OF QPF. THIS SEEMS TO BE A RESULT OF ITS INDICATION OF A
SHARPER THERMAL GRADIENT AND TIGHTER SHORTWAVE. ENSEMBLES GENERALLY
KEEP THE MORE SIGNIFICANT QPF ON THE WARM SIDE OF THE SFC LOW CLOSER
TO THE COAST. HAVE RAISED POPS TO LIKELY SOUTH/EAST OF I-85 CORRIDOR
LATE SAT NIGHT AND SUN MRNG...WITH SOLID CHC ELSEWHERE. QPF IS IN THE
MIDDLE OF THE GUID RANGE...GENERALLY 3/4 TO 1 INCH. VERTICAL PROFILES
WITH STRONG WARM NOSE SUGGEST FREEZING RAIN WOULD RESULT IF ANY SFC
TEMPS WERE BELOW FREEZING...BUT GIVEN CLOUD COVER OVERNIGHT SAT NIGHT
I FAVORED WARMER TEMPS ABOVE FREEZING THROUGHOUT THE AREA.
WHILE THE PIEDMONT/FOOTHILLS DRY OUT LATE SUNDAY AS THE LOW DEPARTS
TO THE NORTHEAST...THE LONGWAVE TROUGH DEEPENS AS IT ABSORBS THE NRN
STREAM TROUGH. COLD FROPA THUS OCCURS IN THE MTNS MONDAY WITH ENOUGH
MOISTURE TO EXPECT A BRIEF NW FLOW SNOW EVENT AND BELOW NORMAL TEMPS
MON-TUE. GFS SUGGESTS LOW PRECIP CHANCES MON NIGHT EAST OF THE MTNS
AS WELL. TEMPS SHOULD BEGIN TO MODERATE BY WED WITH LOW POPS
RETURNING AS LOW PRESSURE CROSSES THE GREAT LAKES DRAGGING A WEAK
FRONT ACRS THE SOUTHEAST.
&&
.AVIATION /06Z THURSDAY THROUGH MONDAY/...
AT KCLT...THE LATEST NAM SOUNDINGS ARE MUCH DRIER AT THE AIRFIELD.
IN FACT...THEY ARE TOO DRY BASED ON THE CLOUD DECK WHICH HAS
RECENTLY MOVED IN. THE RAP SOUNDINGS ARE DOING A BETTER JOB...BUT
EVEN THEN THE MOISTURE IS QUITE SHALLOW. SOME WEAK RADAR RETURNS ARE
SHOWING UP NOW ABOUT 30 NM SOUTH OF THE AIRFIELD. BUT THE AIRMASS
DRIES OUT QUICKLY THE FARTHER NORTH ONE GOES. I THINK ANY PCPN WILL
MISS THE AIRFIELD TO THE SOUTH...BUT I DID ADD A VCSH. THERE IS
STILL A SMALL CHANCE OF A BRIEF PERIOD OF FREEZING RAIN...THOUGH I
SUSPECT THE SFC TEMPERATURES WILL STAY A COUPLE DEGREES ABOVE
FREEZING UNDER THE CLOUD DECK. AS FOR CIG HEIGHTS...THEY SHOULD FALL
TO AROUND 4KFT IN A COUPLE HOURS...THEN CLEAR BY 12-13 UTC. LIGHT
WINDS WILL TURN OUT OF THE NORTH AROUND NOON AS A WEAK COLD FRONT
CROSSES THE REGION.
ELSEWHERE...VFR CIGS WILL CONTINUE OVER THE UPSTATE FOR SEVERAL MORE
HOURS. ANY PCPN SHOULD STAY SOUTHEAST OF THE UPSTATE AIRFIELDS. NOT
EXPECTING THE LOWER VFR CIGS TO MAKE IT INTO KHKY OR KAVL. THE CIGS
WILL CLEAR FROM WEST TO EAST BETWEEN 10-12 UTC. WINDS WILL BE
LIGHT...BUT WILL TURN OUT OF THE NORTH LATER TODAY AS A WEAK COLD
FRONT CROSSES THE REGION.
OUTLOOK...VFR CONDITIONS ARE EXPECTED TO PERSIST THROUGH THE WEEK.
LOW PRESSURE WILL DEVELOP OVER THE NORTHERN GULF ON SATURDAY...
CROSSING THE WESTERN CAROLINAS ON SUNDAY. THIS WILL SPREAD RAIN AND
RESTRICTIVE CIGS AND VSBYS ACROSS THE REGION SATURDAY NIGHT AND
SUNDAY.
CONFIDENCE TABLE...
05-11Z 11-17Z 17-23Z 23-05Z
KCLT HIGH 100% HIGH 100% HIGH 100% HIGH 100%
KGSP HIGH 100% HIGH 100% HIGH 100% HIGH 100%
KAVL HIGH 100% HIGH 100% HIGH 100% HIGH 100%
KHKY HIGH 100% HIGH 100% HIGH 100% HIGH 100%
KGMU HIGH 100% HIGH 100% HIGH 100% HIGH 100%
KAND HIGH 100% HIGH 100% HIGH 100% HIGH 100%
THE PERCENTAGE REFLECTS THE NUMBER OF GUIDANCE MEMBERS AGREEING
WITH THE SCHEDULED TAF ISSUANCE FLIGHT RULE CATEGORY. COMPLETE
HOURLY EXPERIMENTAL AVIATION FORECAST CONSISTENCY TABLES AND ENSEMBLE
FORECASTS ARE AVAILABLE AT THE FOLLOWING LINK: (MUST BE LOWER CASE)
WWW.WEATHER.GOV/GSP/AVIATION_TABLES
&&
.GSP WATCHES/WARNINGS/ADVISORIES...
GA...NONE.
NC...NONE.
SC...NONE.
&&
$$
SYNOPSIS...HG
NEAR TERM...PM/RWH
SHORT TERM...HG
LONG TERM...WIMBERLEY
AVIATION...MCAVOY
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
340 PM CST THU DEC 26 2013
.SHORT TERM...(THIS EVENING THROUGH FRIDAY)
ISSUED AT 340 PM CST THU DEC 26 2013
FOR EARLY THIS EVENING...A WEAKENING TROUGH WILL MOVE EAST INTO
EASTERN WISCONSIN. AS THIS OCCURS...THE OMEGA BETWEEN 750 AND
400 MB WILL QUICKLY WANE AND SO WILL THE LIGHT SNOW ALONG THE
INTERSTATE 94 CORRIDOR. LITTLE...IF ANY...ACCUMULATION IS
EXPECTED.
OVERNIGHT...WARM AIR ADVECTION WILL DEVELOP AHEAD OF AN
APPROACHING WARM FRONT MOVING OUT OF THE NORTHERN PLAINS.
850 MB TEMPERATURES WARM FROM AROUND -6C TO 0C BY SUNRISE
FRIDAY. IN ADDITION...OMEGA BETWEEN 600 AND 300 MB WILL RESULT IN
AN INCREASE IN THE MID AND HIGH CLOUDS. EARLIER TODAY...THE BUFKIT
SOUNDINGS WERE SHOWING THE MOISTURE DRAMATICALLY INCREASING BELOW
925 MB. AS A RESULT...THERE WAS SOME CONCERN OF SOME SHALLOW FOG
DEVELOPING ACROSS THE FORECAST AREA. HOWEVER THE LATEST RAP AND
NAM/WRF HAVE STARTED TO BACK AWAY FROM THIS SOLUTION.
ON FRIDAY...A WARM FRONT WILL MOVE QUICKLY EAST ACROSS THE AREA.
925 MB TEMPERATURES WARM FROM AROUND 0C INTO THE 2 TO 6C RANGE BY
SUNSET. THIS WILL RESULT IN HIGH TEMPERATURES WARMING INTO THE
LOWER TO MID 30S WHICH IS ABOUT 10 DEGREES ABOVE NORMAL.
.LONG TERM...(FRIDAY NIGHT THROUGH THURSDAY)
ISSUED AT 340 PM CST THU DEC 26 2013
ON SATURDAY...SOUTHWEST WINDS ALOFT WILL CONTINUE TO ADVECT WARM
AIR INTO THE REGION FROM THE CENTRAL AND SOUTHERN PLAINS. THIS
WILL ALLOW TEMPERATURES TO CLIMB INTO THE MID AND UPPER 30S.
ON SATURDAY NIGHT AND EARLY SUNDAY MORNING...A STRONG ARCTIC COLD
FRONT WILL MOVE QUICKLY SOUTH THROUGH THE FORECAST AREA. WITH MUCH
OF THE FLOW PRECEDING THIS FRONT BEING FROM THE WEST AND
SOUTHWEST...THERE WILL BE VERY LITTLE MOISTURE FOR THIS FRONT TO
WORK WITH. SOUNDINGS SUGGEST THAT AS THE MOISTURE INCREASES IN THE
LOW LEVELS THERE WILL NO ICE CRYSTALS AVAILABLE...BUT THIS QUICKLY
CHANGES ABOUT AN HOUR AFTER PRECIPITATION ONSET. AS A
RESULT...THERE MAY BE A BRIEF PERIOD OF FREEZING DRIZZLE PRIOR TO
THE PRECIPITATION CHANGING OVER TO SNOW. WITH MUCH OF THE FORCING
WITH THE LONG WAVE TROUGH MOVING QUICKLY EAST OF THE AREA...NOT
EXPECTING MUCH SNOW WITH THIS SYSTEM.
ON SUNDAY...STRONG COLD AIR ADVECTION WILL BE SEEN ACROSS THE
AREA. THE INITIAL SURGE WILL CAUSE TEMPERATURES TO FALL INTO THE 5
TO 15 DEGREE RANGE...AND THEN TEMPERATURES WILL STABILIZE FOR THE
REMAINDER OF THE DAY. NORTHWEST WINDS IN THE 15 TO 25 KNOT RANGE
WILL PRODUCE WIND CHILLS IN THE 0 TO 20 BELOW RANGE DURING THE
AFTERNOON. THERE IS ALSO SOME CONCERN THAT THERE MAY BE SOME
BLOWING AND DRIFTING SNOW...BUT THE CONFIDENCE WAS TOO LOW AT THIS
TIME TO BE INCLUDED IN THE FORECAST GRIDS AT THIS TIME. THIS WAS
MAINLY DUE TO THE POSSIBILITY THAT THE COLD AIR COULD POTENTIALLY
LOCK UP THE SNOW IN THE SNOW PACK AND PREVENT IT FROM MOVING.
FROM SUNDAY NIGHT INTO MONDAY MORNING...TEMPERATURES WILL FALL
INTO THE -5 TO 5 DEGREE RANGE AND THE NORTHWEST WINDS WILL REMAIN
IN THE 5 TO 15 KNOT RANGE. THIS WILL PRODUCE WIND CHILLS IN THE
-20 TO -35 DEGREE RANGE ACROSS THE ENTIRE AREA. LIKE THE PAST
COUPLE OF DAYS...EXPECT A WIND CHILL ADVISORY TO BE NEEDED FOR
THIS TIME PERIOD.
FROM MONDAY NIGHT INTO NEW YEARS DAY...ANOTHER ARCTIC COLD FRONT
WILL MOVE THROUGH THE AREA ON MONDAY NIGHT. THIS FRONT WILL BRING
EVEN COLDER AIR INTO THE REGION. THE GEM HAS THE COLDEST
TEMPERATURES WITH LOW TEMPERATURES FALLING INTO -15 TO -25 DEGREE
RANGE ON TUESDAY MORNING AND INTO THE -25 TO -45 DEGREE RANGE ON
WEDNESDAY MORNING. MEANWHILE THE GFS IS THE WARMEST WITH
TEMPERATURES RANGING FROM -5 TO 10F ON TUESDAY MORNING...AND FROM
-5 TO -20F ON WEDNESDAY MORNING. WITH THE ECMWF A FEW DEGREES
COLDER THAN THE MODEL CONSENSUS...WENT A 2 TO 4 DEGREES COLD THAN
THE ALL BLEND TEMPERATURES.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z FRIDAY AFTERNOON)
ISSUED AT 1200 PM CST THU DEC 26 2013
A WEAK UPPER LEVEL DISTURBANCE WILL PASS JUST NORTH OF THE TAF
SITES THIS AFTERNOON AND MAY GENERATE SOME FLURRIES OR VERY LIGHT
SNOW AT THE TAF SITES AS IT MOVES THROUGH. CANNOT RULE OUT A BRIEF
DROP TO MVFR CONDITIONS IF THE SNOW TRACKS FURTHER SOUTH...BUT
ANTICIPATE VFR CONDITION THROUGH THE AFTERNOON HOURS INTO EARLY
THIS EVENING. WARMER AIR MOVING IN ALOFT MAY HELP TO GENERATE SOME
AREAS OF FOG AND STRATUS TONIGHT. CONFIDENCE IS LOW ON THE STRATUS
DEVELOPING. THINKING SOME AREAS OF BR WILL BE THE MOST LIKELY
SCENARIO TONIGHT SO HAVE INTRODUCED A 3SM BR AT KLSE STARTING AT
07Z AND 5SM BR AT KRST STARTING AT 03Z. WILL HAVE TO KEEP A CLOSE
EYE THIS TONIGHT WITH THE FORECAST SOUNDINGS SHOWING SATURATION
NEAR THE SURFACE.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
SHORT TERM...BOYNE
LONG TERM...BOYNE
AVIATION...WETENKAMP
AREA FORECAST DISCUSSION
NWS MILWAUKEE/SULLIVAN WI
253 PM CST THU DEC 26 2013
.SHORT TERM...
.TONIGHT AND FRIDAY...FORECAST CONFIDENCE...MEDIUM
UPSTREAM RADAR AND OBSERVATIONS SHOW LIGHT SNOW CONTINUING TO FALL
ACROSS SOUTHEAST MINNESOTA AND NORTHWEST WISCONSIN. WILL THUS
PROBABLY SEE A CHANCE FOR LIGHT SNOW CONTINUE INTO THE
EVENING...WINDING DOWN BY LATE EVENING AS THE SHORTWAVE FINALLY
BEGINS TO MAKE IT THROUGH THE AREA. NOT MUCH MORE THAN A DUSTING TO
A TENTH OF AN INCH OR TWO OF SNOW EXPECTED FROM HERE ON OUT.
ONCE AGAIN...CONCERNED ABOUT LOW TEMPS FOR TONIGHT...AS MODELS
DIFFERING QUITE A BIT WITH THE EXTENT OF CLOUD COVER. BASED ON
LATEST SATELLITE AND NAM/RAP LOW LEVEL MOISTURE...HAVE TRENDED
CLOUDIER FOR TONIGHT AND THUS TOWARD THE MILDER MODEL SOLUTIONS.
WITH VERY LIGHT WINDS EXPECTED THOUGH...TEMPS COULD DROP A FAIR
AMOUNT BELOW FORECAST VALUES IN SPOTS WHERE ANY CLEARING DOES OCCUR.
LOOKS LIKE A BRIEF BREAK IN TRENDS FOR TOMORROW...WITH NO
PRECIPITATION EXPECTED AND HIGH TEMPS NEAR TO EVEN A COUPLE DEGREES
ABOVE AVERAGE VALUES.
FRIDAY NIGHT AND SATURDAY...FORECAST CONFIDENCE...HIGH
THE 250 MB NORTHERN STREAM JET IS ACROSS THE U.S. CANADIAN BORDER
WITH A LARGE JET MAX MOVING ACROSS THE LAKE SUPERIOR AREA FRIDAY
NIGHT. WEAK UPPER DIVERGENCE BEGINS SATURDAY. 700 MB WARM
ADVECTION OCCURS FRIDAY NIGHT AND SATURDAY. 700 MB UPWARD MOTION
BEGINS SATURDAY. 700 MB RH DECREASES EARLY FRIDAY EVENING AND
BEGINS TO MOISTEN SATURDAY. 850 MB RH IS RATHER DRY. AND NO
PRECIPITATION IS EXPECTED. THERE SHOULD BE A STRONG LOW LEVEL
INVERSION SATURDAY...SO WINDS WILL NOT MIX DOWN MUCH.
SATURDAY NIGHT AND SUNDAY...FORECAST CONFIDENCE...HIGH
THE RIGHT ENTRANCE REGION OF THE 250 MB JET MAX IS OVER WISCONSIN
SATURDAY NIGHT AS THE BROAD UPPER TROUGH MOVES INTO THE UPPER
MISSISSIPPI VALLEY SUNDAY. THE WEAK UPPER DIVERGENCE CONTINUES
SATURDAY NIGHT AND INTO SUNDAY MORNING. 700 MB COLD AIR ADVECTION
BEGINS SATURDAY NIGHT AND CONTINUES SUNDAY. THE 700 MB UPWARD
MOTION CONTINUES SATURDAY NIGHT THEN BECOMES DOWNWARD ON SUNDAY.
THE 700 MB RH NEVER SATURATES SATURDAY NIGHT THEN DRIES ON
SUNDAY. 850 MB LAYERS SATURATE LATE SATURDAY NIGHT BUT DRIES
SATURDAY AFTERNOON. DUE TO DRY AIR BETWEEN 3 AND 12 THSD FT AND
MOIST LOW LEVELS...SOME FREEZING DRIZZLE IS POSSIBLE SATURDAY
NIGHT WITH TEMPERATURES STILL ABOVE FREEZING AT 5 THSD FT.
A SURFACE COLD FRONT MOVES ACROSS SOUTHERN WISCONSIN SATURDAY
NIGHT WITH BRISK NORTH WINDS SUNDAY WITH FALLING TEMPERATURES.
LIGHT POST FRONTAL PRECIPITATION SHOULD BRING A DUSTING OF LIGHT
SNOW SATURDAY NIGHT. THE INVERSION REMAINS BUT LIFTS...WITH THE
UNSTABLE LAYERS BELOW 3 THSD FT. FLURRIES EXPECTED SUNDAY DUE TO
MOIST AND RATHER UNSTABLE LOW LEVELS ON SUNDAY.
.LONG TERM...
.SUNDAY NIGHT AND MONDAY...FORECAST CONFIDENCE...HIGH
THE 500 MB TROUGH AXIS MOVES ACROSS WISCONSIN WITH THE 00Z ECMWF
PUSHING TIT EAST QUICKER. STRONG COLD AIR ADVECTION CONTINUES
WITH 510 THICKNESS VALUES BY MONDAY MORNING. WIND CHILLS OF 20 TO
30 BELOW ZERO ARE LIKELY SUNDAY NIGHT INTO EARLY MONDAY.
THE 12Z GFS HAS HIGH PRESSURE OVER WISCONSIN MONDAY...WHILE THE
00Z ECMWF BRINGS SOME VERY LIGHT SNOW IN THE BAROCLINIC
ZONE...ESPECIALLY IN SOUTHWEST AREAS. THE GFS IS A LITTLE SLOWER
WITH THIS.
TUESDAY THROUGH THURSDAY...FORECAST CONFIDENCE...HIGH
A SECOND TROUGH DIGS INTO WISCONSIN...BUT THE BASE OF THE TROUGH
REMAINS OVER THE UPPER GREAT LAKES ON THE GFS. THE ECMWF IS A
LITTLE FASTER AND DEEPER. THEN THE FLOW IS MORE ZONAL ON THE ECMWF
WITH A LINGERING TROUGH OVER THE UPPER MISSISSIPPI VALLEY ON THE
GFS.
HIGH PRESSURE DOMINATES ACROSS THE GREAT LAKES TUESDAY AND
WEDNESDAY. WIND CHILLS OF 10 TO 20 BELOW ZERO ARE POSSIBLE
TUESDAY NIGHT INTO EARLY WEDNESDAY...BUT WINDS ARE LIGHTER ON THE
00Z ECMWF.
WARM AIR ADVECTION BEGINS THURSDAY AS THE HIGH MOVES EAST.
&&
.AVIATION/00Z TAFS/...
ON AND OFF LIGHT SNOW WILL CONTINUE INTO EARLY EVENING. COULD SEE
VISIBILITIES DOWN TO AROUND 4 MILES AT TIMES...WITH NOT MUCH MORE
THAN A DUSTING TO A TENTH OR TWO EXPECTED FROM HERE ON OUT. EXPECT
DRY WEATHER THEN FROM LATE EVENING THROUGH FRIDAY.
LATEST RAP AND NAM ARE SUGGESTING MOSTLY CLOUDY SKIES WILL LINGER
THROUGH MUCH OF THE NIGHT. HAVE TAFS REMAINING VFR...AS THE MAJORITY
OF UPSTREAM OBS ARE VFR. SEEING SOME MVFR MIXED IN THERE THOUGH...SO
WOULD NOT BE SURPRISED AT BRIEFLY LOWER CLOUDS THIS EVENING AND
OVERNIGHT. SHOULD SEE SOME BREAKS IN THE CLOUDS BY TOMORROW
MORNING...WITH A DECENT CHANCE AT SOME SUNSHINE BY LATE MORNING AND
AFTERNOON.
&&
.MKX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
LM...NONE.
&&
$$
TONIGHT/FRIDAY AND AVIATION/MARINE...DDV
FRIDAY NIGHT THROUGH THURSDAY...HENTZ
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
1200 PM CST THU DEC 26 2013
.SHORT TERM...(TODAY THROUGH FRIDAY)
ISSUED AT 335 AM CST THU DEC 26 2013
MAIN WEATHER HAPPENINGS WILL BE MORE LIGHT SNOW FOR TODAY...THEN
SOME MODERATION IN TEMPERATURES ON FRIDAY.
WATER VAPOR SATELLITE LOOP COUPLED WITH RAP 500MB ANALYSIS SHOWS THE
NATION DOMINATED BY A LONG WAVE TROUGH OF LOW PRESSURE WITH
NORTHWEST FLOW INTO THE UPPER MISSISSIPPI RIVER VALLEY REGION. AN
EMBEDDED SHORT WAVE TROUGH WAS MOVING INTO THE DAKOTAS EARLY THIS
MORNING...TOWARD OUR FORECAST AREA. MEANWHILE...IR SATELLITE/SURFACE
OBSERVATIONS SHOWING STRATUS CLOUDS ENSHROUDING THE REGION...TRAPPED
UNDER A WEAK RIDGE OF HIGH PRESSURE THAT EXTENDED FROM THE MID AND
UPPER MISSISSIPPI RIVER VALLEY REGIONS INTO NORTHERN MN. RADAR
MOSAIC AND SURFACE OBSERVATIONS SHOWING SOME LIGHT SNOW FLURRY
ACTIVITY ACROSS PORTIONS OF WEST CENTRAL WISCONSIN AND ACROSS CENTRAL
AND NORTHERN MN. LIGHT SNOW WAS FALLING WITH A BIT MORE FERVOR
ACROSS PORTIONS OF ND IN ADVANCE OF THAT MID-LEVEL TROUGH WITH SOME
VISIBILITY RESTRICTIONS IN THE 4-5SM RANGE.
WILL BE WATCHING THAT MID-LEVEL TROUGH MOVE FROM THE DAKOTAS INTO
OUR REGION BY MID-MORNING WITH DECENT ISENTROPIC LIFT DEPICTED BY
THE NAM AND RAP ON THE 275K SURFACE...OR MAINLY IN THE 900-800MB
LAYER. WILL LIKELY SEE SNOW AMOUNTS IN THE 1/2 TO 1 INCH RANGE
THROUGH THE DAY WITH THIS WAVE BEFORE IT DEPARTS SOUTHEAST BY THIS
EVENING. OTHERWISE...LOOK FOR HIGHS TODAY IN THE TEENS ACROSS NORTH
CENTRAL WI...TO THE MID/UPPER 20S ELSEWHERE.
SOME LINGERING VERY LIGHT SNOW MAY STILL BE SEEN THIS EVENING EAST
OF THE MISSISSIPPI ON THE TAIL END OF THE PASSING TROUGH...BUT THEN
CLOUDS ARE EXPECTED TO DECREASE AFTER MIDNIGHT FROM SOUTHWEST TO
NORTHEAST AS A WEAK RIDGE OF HIGH PRESSURE BUILDS IN BEHIND THE
DEPARTING WAVE.
MODERATING TEMPERATURES EXPECTED ON FRIDAY AS SOUTHWEST WINDS KICK
IN ON THE BACKSIDE OF THE DEPARTING HIGH AND IN ADVANCE OF LOW
PRESSURE MOVING ALONG THE U.S./CANADIAN BORDER. NAM AND ECMWF
BULLISH WITH 925MB TEMPERATURES WARMING INTO THE 0 TO +5C RANGE
WHEREAS THE GFS IS ONLY IN THE -2 TO +3C RANGE. MODEL CONSENSUS
YIELDS HIGHS IN THE UPPER 20S ACROSS CENTRAL WI...TO THE LOWER 30S
FOR AREAS SOUTHWEST OF THE I-94 CORRIDOR. HOWEVER...SOUTHWEST WINDS
IN THE 10-20MPH RANGE WILL MAKE IT FEEL MORE LIKE THE UPPER TEENS TO
LOWER 20S.
.LONG TERM...(FRIDAY NIGHT THROUGH NEW YEARS DAY)
ISSUED AT 335 AM CST THU DEC 26 2013
WARM AIR ADVECTION WILL CONTINUE FRIDAY NIGHT INTO SATURDAY AS THE
AREA REMAINS IN THE WARM SECTOR OF LOW PRESSURE MOVING ACROSS
SOUTHERN ONTARIO CANADA. LOOK FOR LOWS FRIDAY NIGHT IN THE LOW TO
MID 20S WITH HIGHS ON SATURDAY EXPECTED TO TOP OFF IN THE LOWER AND
MIDDLE 30S. AN ARCTIC COLD FRONT IS THEN SLATED TO DROP THROUGH THE
AREA SATURDAY NIGHT.
WILL HAVE TO KEEP AN EYE ON PRECIPITATION TYPE SATURDAY NIGHT AS THE
GFS BUFKIT SOUNDING HINTING AT LOW LEVEL SATURATION UP TO 800MB WITH
NO ICE PRESENT IN THE CLOUD AS THE FRONT MOVES IN. AS SUCH...ADDED
THE MENTION OF FREEZING DRIZZLE INTO THE WEATHER GRIDS ALONG WITH
THE CHANCE OF LIGHT SNOW. BY EARLY SUNDAY MORNING...IT APPEARS THE
SATURATED COLUMN WILL HAVE ICE PRESENT FOR ALL LIGHT SNOW.
BY SUNDAY MORNING...PLAN ON TEMPERATURES DROPPING INTO THE SINGLE
DIGITS AND TEENS ABOVE ZERO WITH ONLY A 2 TO 3 DEGREE RISE DURING
THE DAY SUNDAY. SOME LIGHT SNOW WILL STILL BE POSSIBLE MAINLY EAST OF
THE MISSISSIPPI RIVER. BRISK NORTHWEST WINDS WILL ADD TO THE CHILL
SUNDAY AS WELL WITH WIND CHILL VALUES FALLING INTO THE -15 TO
-25 DEGREE RANGE ACROSS SOUTHEAST MN/NORTHEAST IA IN
THE AFTERNOON.
VERY COLD WIND CHILLS WILL BE SEEN SUNDAY NIGHT...LASTING THROUGH
TUESDAY MORNING//COLDEST EARLY MONDAY MORNING// AS THE ARCTIC AIR
CONTINUES TO SPILL INTO THE REGION. WIND CHILL HEADLINES WILL LIKELY
BE NEEDED. LOWEST WIND CHILL VALUES MONDAY MORNING COULD BE AS LOW
AS -25 TO -35 DEGREES. SLIGHT MODERATION IN TEMPERATURES MAY BE SEEN
LATER TUESDAY THROUGH WEDNESDAY AS THE HEART OF THE ARCTIC AIR MOVES
MORE INTO THE GREAT LAKES REGION.
EMBEDDED SHORTWAVE TROUGHS EMBEDDED IN THE NORTHWEST FLOW WILL ALSO
GIVE THE AREA PERIODIC LIGHT SNOW CHANCES FROM MONDAY NIGHT THROUGH
WEDNESDAY.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z FRIDAY AFTERNOON)
ISSUED AT 1200 PM CST THU DEC 26 2013
A WEAK UPPER LEVEL DISTURBANCE WILL PASS JUST NORTH OF THE TAF
SITES THIS AFTERNOON AND MAY GENERATE SOME FLURRIES OR VERY LIGHT
SNOW AT THE TAF SITES AS IT MOVES THROUGH. CANNOT RULE OUT A BRIEF
DROP TO MVFR CONDITIONS IF THE SNOW TRACKS FURTHER SOUTH...BUT
ANTICIPATE VFR CONDITION THROUGH THE AFTERNOON HOURS INTO EARLY
THIS EVENING. WARMER AIR MOVING IN ALOFT MAY HELP TO GENERATE SOME
AREAS OF FOG AND STRATUS TONIGHT. CONFIDENCE IS LOW ON THE STRATUS
DEVELOPING. THINKING SOME AREAS OF BR WILL BE THE MOST LIKELY
SCENARIO TONIGHT SO HAVE INTRODUCED A 3SM BR AT KLSE STARTING AT
07Z AND 5SM BR AT KRST STARTING AT 03Z. WILL HAVE TO KEEP A CLOSE
EYE THIS TONIGHT WITH THE FORECAST SOUNDINGS SHOWING SATURATION
NEAR THE SURFACE.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
SHORT TERM...DAS
LONG TERM....DAS
AVIATION...WETENKAMP
AREA FORECAST DISCUSSION...UPDATED
NWS MILWAUKEE/SULLIVAN WI
1041 AM CST THU DEC 26 2013
.UPDATE...AGAIN...MAIN CONCERN IN THE ONGOING TODAY PERIOD IS
POPS/WX. CURRENTLY A SWATH OF A LIGHT SNOW/FLURRIES IS ORIENTED NW-
SE ACROSS MUCH OF THE CWA AND DOWN TO CHICAGO. IN REGARD TO
REFLECTIVITY TRENDS...THERE HAS BEEN A SLIGHT UPTICK IN REFLECTIVITY
VALUES THE LAST TWO AND HALF HOURS...WITH VALUES AROUND 20-TO 25 DBZ
AT 1030 AM. SFC OBS SHOW THE LOWEST SFC VIS AROUND 3-4 SM WITHIN
THIS AREA GENERALLY...SO ITS EXPECTED THAT IT CONTAINS MOSTLY LIGHT
SNOW T0 FLURRIES AT THE PERIPHERY.
AN APPROACHING S/W TROUGH AND VORT LOBE AT 500 HPA WILL BE
TRAVERSING THE CWA THIS AFTERNOON/EVENING. CURRENT FORECAST AND
EXPECTATION IS FOR LIGHT SNOW TO DEVELOP/BLOSSOM THIS AFTERNOON AND
EVENING IN ASSOCIATION WITH THIS WAVE. THOUGH A BIT CONCERNED GIVEN
THE DIFFERENCES IN MODEL OUTPUT. LATEST HRRR RUN AND DIFFERENT
FLAVORS OF WRF SHOW ZERO TO SCANT QPF WHILE THE COARSER GFS AND
ECMWF PUTS OUT A FEW HUNDREDTHS. DECENT WARM AIR ADVECTION IN THE
LOW-LEVELS AND A 850 HPA WAVE ARE PRESENT. OTHERWISE...MODEST UPWARD
VERTICAL ASCENT PRESENT AND PROXIMITY SOUNDINGS SHOW DECENT
SATURATION AND RH IN THE LOW-LEVELS AND IN THE DENDRITE GROWTH ZONE.
HOWEVER...OMEGA/UVV NOT THE STRONGEST OR CENTERED QUITE ON THE
DGZ...BUT LIFT SHOULD BE SUFFICIENT DESPITE THE LOW MOISTURE THAT IS
AVAILABLE. QPF FORECAST IS LOW AT JUST A COUPLE HUNDREDTHS AND
SNOW-LIQUID RATIOS ARE FCST AROUND 14:1-18:1...SO AMOUNTS AROUND
A HALF AN INCH EXPECTED. REST OF THE FORECAST WAS ADJUSTED FOR
LATEST TRENDS. THIS WILL HAVE TO BE MONITORED BUT POPS WERE KEPT
HIGH GIVEN THE LIFT. REST OF THE FORECAST PACKAGE WASNT ALTERED
MUCH...BUT WERE ADJUSTED FOR LATEST TEMP/WIND TRENDS.
&&
.AVIATION/18Z TAFS/...THERE WILL BE ON AND OFF LIGHT SNOW TODAY.
COULD SEE VISIBILITIES DOWN TO AROUND 3 MILES AT TIMES...WITH A
DUSTING TO A HALF OF AN INCH POSSIBLE BY EVENING. THE SNOW WILL
WIND DOWN THIS EVENING...WITH DRY WEATHER THEN EXPECTED OVERNIGHT
AND FRIDAY.
LOOKS LIKE MAINLY VFR CIGS THROUGH TOMORROW...THOUGH SOME MVFR CIGS
POSSIBLE AT TIMES THROUGH TONIGHT GIVEN UPSTREAM CONDITIONS.
&&
.PREV DISCUSSION... /ISSUED 347 AM CST THU DEC 26 2013/
SHORT TERM...
TODAY AND TONIGHT-FORECAST CONFIDENCE HIGH
LIGHT SNOW MAKING IT/S WAY TOWARD THE WESTERN CWA THIS MORNING WITH
FASTER ADVANCE OF WARM AIR ADVECTION AHEAD OF SHORT WAVE MOVING SE
FROM THE ERN DAKOTAS...SO HAVE BROUGHT POPS IN A BIT SOONER AND
RAISED THEM IN THE WEST LATER THIS MORNING.
STILL LOOKS LIKE THIS AFTERNOON WILL BE THE PRIME TIME PERIOD FOR
LIGHT SNOW... DIMINISHING FROM WEST TO EAST LATE IN THE AFTERNOON
INTO THE EARLY EVENING. KEPT CHANCE/SLIGHT CHANCE POPS THROUGH THE
EVENING...MAINLY IN THE EASTERN HALF OF THE CWA UNTIL 500 MB TROUGH
CLEARS TO THE EAST. LOW AMOUNTS OF QPF AVAILABLE SO IN SPITE OF
SNOW/LIQUID RATIOS AROUND 15:1 TO 17:1...WILL ONLY SEE BETWEEN 1/2
INCH TO 1 INCH ACROSS THE CWA..WHICH WILL BE ENOUGH TO SLICKEN UP
THE ROADS.
WARM ADVECTION BRINGS HIGHS UP TO THE LOWER TO MIDDLE 20S
TODAY...WITH EARLY CLOUDS AND ONLY WEAK COLD ADVECTION BEHIND THE
SHORT WAVE KEEPING LOWS IN THE LOW TO MID TEENS TONIGHT.
FRIDAY-FORECAST CONFIDENCE HIGH
RIDGE BUILDS OVER GREAT LAKES AREA WITH 60-100 METER 500 MB HEIGHT
RISES AND STRONG LOW LEVEL WARM ADVECTION. 45 KNOT WESTERLY JET
INCREASES 850 MB TEMP ABOUT 10C IN 24 HOURS TO THE +5C RANGE.
NATURALLY THERE WILL BE A LOW LEVEL INVERSION GIVEN THE SNOW
PACK...BUT TEMPERATURES WELL INTO THE 20S SEEM PLAUSIBLE AND EVEN
LOWER 30S ALONG THE ILLINOIS BORDER.
SATURDAY-FORECAST CONFIDENCE HIGH
SHORT WAVE TROUGH MOVES FROM NORTHERN ROCKIES INTO DAKOTAS WITH
LITTLE CHANGE IN HEIGHTS OVER WISCONSIN. HOWEVER...FLOW TILTS MORE
WESTERLY AND SHOULD CONTINUE TO ALLOW FOR STRONG WARMING INTO
GREAT LAKES AHEAD OF STRONG SURFACE COLD FRONT.
SURFACE LOW EXPECTED TO BE OVER SOUTHERN MINNESOTA OR IOWA BY THE
AFTERNOON...WITH SURGE OF +8C 850 MB AIR ACROSS SOUTHERN
WISCONSIN. AGAIN EXPECTING A STRONG LOW LEVEL INVERSION INDUCED BY
SNOWPACK. THE TOUGH CALL WILL BE IN THE WEST-SOUTHWEST TRAJECTORY
ALIGNED NEARLY PARALLEL WITH THE AXIS OF THE SNOW PACK FROM KANSAS
TO SOUTHERN IOWA/NORTHERN MISSOURI AND INTO NORTHERN ILLINOIS.
CERTAINLY WILL BE A STRONG THERMAL GRADIENT NEAR THE SOUTHERN EDGE
OF THE MELTING SNOWPACK ROUGHLY FROM KANSAS CITY TO BURLINGTON
IOWA TO CHICAGO...BUT HOW FAR NORTH THAT GETS IS IN DOUBT. 15-20
DEGREE THERMAL GRADIENTS FROM BARE GROUND TO SNOWPACK ARE NOT
UNCOMMON IN THESE SITUATIONS SO EXPECT IT TO GO FROM 30S TO 50S
ACROSS SOUTHERN WISCONSIN INTO CENTRAL ILLINOIS.
AT NIGHT...THE BRIEF MILD PARTY IS OVER AS SURFACE LOW MOVES
ACROSS SOUTHERN WISCONSIN INTO LOWER MICHIGAN AND NEXT POLAR BLAST
MOVES IN. MOST OF THE PRECIPITATION WILL SKIRT BY TO THE NORTH BUT
A SHALLOW LAYER OF MOISTURE BELOW THE FRONTAL INVERSION WILL
DEEPEN WITH TIME. SINCE THE BULK OF THE MOISTURE IS WARMER THAN
ABOUT -7 TO -5C IN THE SOUNDING...LOOKS MORE LIKE A FREEZING
DRIZZLE OR LIGHT FREEZING RAIN THERMAL PROFILE FOR A WHILE BEFORE
TURNING TO SNOW OR SNOW GRAINS TOWARD MORNING.
LONG TERM...
SUNDAY-FORECAST CONFIDENCE HIGH
850 MB TEMPS CRASH TO ABOUT -14C BY THE AFTERNOON WITH BRISK NORTH
WINDS USHERING IN FALLING TEMPERATURES. TEMPERATURES SHOULD FALL
THROUGH THE TEENS AND INTO THE SINGLE DIGITS BY EVENING. NOT MUCH
PRECIPITATION LIKELY ALTHOUGH GFS HAS A MORE AGGRESSIVE POST
FRONTAL FRONTOGENETIC LIGHT SNOW LOOK TO IT THAN OTHER MODELS AS
AMPLIFYING UPPER TROUGH APPROACHES. CIPS ANALOGS WHICH FOLLOW GFS
DO SHOW SURPRISINGLY HIGH (40%) PROBABILITIES OF 2+" SNOWS.
WIND CHILL READINGS SHOULD FALL BELOW ZERO IN THE EARLY EVENING
AND THEN INTO -20 TO -25F RANGE BETWEEN MIDNIGHT AND ABOUT 9 AM
MONDAY MORNING. CONFIDENCE CONTINUES TO INCREASE THAT A WIND CHILL
ADVISORY WILL BE NEEDED WITH THIS EVENT.
MONDAY-FORECAST CONFIDENCE MEDIUM
MAIN STORY WILL BE BITTER COLD. CIPS ANALOGS SHOW 50-70% CHANCE OF
BELOW ZERO TEMPERATURES FROM NORTH TO SOUTH ACROSS CWA. MORNING
LOWS WILL BE IN THE ZERO TO 10 BELOW RANGE. WIND CHILL VALUES ONLY
RISE TO ABOUT -10F DURING THE AFTERNOON WITH HIGHS IN THE SINGLE
DIGITS ABOVE ZERO.
WIND CHILLS WILL FALL BACK TO -15 TO -25F RANGE MONDAY EVENING
INTO TUESDAY MORNING. SO THERE WILL LIKELY BE A COUPLE OF
POSSIBILITIES FOR WIND CHILL ADVISORIES OR PERHAPS ONE LONG TWO
DAY HEADLINE FOR SIMPLICITY.
ALTHOUGH CONFIDENCE IN COLD IS HIGH...CONFIDENCE IN LIGHT SNOW
POTENTIAL IS RATHER LOW. TIMING OF WEAK CLIPPER LIKE SYSTEM RANGES
FROM MONDAY ON ECMWF TO TUESDAY FOR GFS AND CANADIAN GEMNH. BEST
BET IS TO STRING LOW POPS ACROSS BOTH DAYS TO COVER THE
POSSIBILITIES. CIPS ANALOGS DO SHOW 50% PROBS OF 2+" OF SNOW
DURING THE PERIOD. THE ECMWF 24 HOURS AGO HAD QUITE A BIT OF
QPF...BUT ONLY THE GEMNH HOLDS ONTO A DECENT AMOUNT IN THE 0.10 TO
0.20" RANGE.
TUESDAY-FORECAST CONFIDENCE LOW
NOT MUCH MODERATION IN TEMPERATURES EXPECTED AND MUCH OF THIS IS
DEPENDENT ON WEAK LOW PRESSURE WAVES AND CLOUD COVER. LEANING
TOWARD IT BEING ABOUT 5 DEGREES WARMER THAN MONDAY BUT STILL
BITTERLY COLD. NEW YEARS EVE ENTHUSIASTS IN THE LATE EVENING CAN
LOOK FORWARD TO TEMPERATURES AROUND ZERO AND WIND CHILL VALUES OF
10 TO 15 BELOW ZERO.
WEDNESDAY/NEW YEARS DAY-FORECAST CONFIDENCE MEDIUM
A BIT MORE MODERATION EXPECTED BUT STILL ON THE ORDER OF 10 DEGREES
BELOW NORMAL TO START OFF 2014.
AVIATION/12Z TAFS/...
A PERIOD OF SCATTERED CIGS AND VFR VSBYS WITH WEAK SURFACE RIDGING
BETWEEN UPPER WAVES ...BUT VFR LEVEL CLOUDS WILL QUICKLY SPREAD OVER
THE REGION EARLY THIS MORNING. LIGHT SNOW WILL BE RETUNING TO KMSN
LATE THIS MORNING...AND EASTERN SITES THIS AFTERNOON...WITH WARM
ADVECTION AHEAD OF THE NEXT WAVE. UPSTREAM OBS INDICATE VFR CIGS
WITH VERY LIGHT SNOW...WITH PERIODS OF MVFR CIGS VSBYS EXPECTED FOR
2-3 HOURS MAINLY THIS AFTERNOON. ALL THE LIGHT SNOW WILL EXIT
EASTERN TAF SITES BY 06Z...WITH ONLY VERY LIGHT SNOW OR FLURRIES
AFTER THE 00Z-03Z TIME PERIOD.
MARINE...
WINDS WILL REMAIN BELOW SMALL CRAFT CRITERIA UNTIL FRIDAY AFTERNOON/
EVENING...WHICH BEGINS A PERIOD OF SMALL CRAFT CONDITIONS AS A
SERIES OF LOW PRESSURE SYSTEMS CROSS THE GREAT LAKES REGION FOLLOWED
BY AN ARCTIC AIRMASS BUILDING IN SUNDAY NIGHT AND MONDAY.
&&
.MKX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
LM...NONE.
&&
$$
UPDATE...ET/DDV
TODAY/TONIGHT AND AVIATION/MARINE...REM
FRIDAY THROUGH WEDNESDAY...CRAVEN
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
510 AM CST THU DEC 26 2013
.SHORT TERM...(TODAY THROUGH FRIDAY)
ISSUED AT 335 AM CST THU DEC 26 2013
MAIN WEATHER HAPPENINGS WILL BE MORE LIGHT SNOW FOR TODAY...THEN
SOME MODERATION IN TEMPERATURES ON FRIDAY.
WATER VAPOR SATELLITE LOOP COUPLED WITH RAP 500MB ANALYSIS SHOWS THE
NATION DOMINATED BY A LONG WAVE TROUGH OF LOW PRESSURE WITH
NORTHWEST FLOW INTO THE UPPER MISSISSIPPI RIVER VALLEY REGION. AN
EMBEDDED SHORT WAVE TROUGH WAS MOVING INTO THE DAKOTAS EARLY THIS
MORNING...TOWARD OUR FORECAST AREA. MEANWHILE...IR SATELLITE/SURFACE
OBSERVATIONS SHOWING STRATUS CLOUDS ENSHROUDING THE REGION...TRAPPED
UNDER A WEAK RIDGE OF HIGH PRESSURE THAT EXTENDED FROM THE MID AND
UPPER MISSISSIPPI RIVER VALLEY REGIONS INTO NORTHERN MN. RADAR
MOSAIC AND SURFACE OBSERVATIONS SHOWING SOME LIGHT SNOW FLURRY
ACTIVITY ACROSS PORTIONS OF WEST CENTRAL WISCONSIN AND ACROSS CENTRAL
AND NORTHERN MN. LIGHT SNOW WAS FALLING WITH A BIT MORE FERVOR
ACROSS PORTIONS OF ND IN ADVANCE OF THAT MID-LEVEL TROUGH WITH SOME
VISIBILITY RESTRICTIONS IN THE 4-5SM RANGE.
WILL BE WATCHING THAT MID-LEVEL TROUGH MOVE FROM THE DAKOTAS INTO
OUR REGION BY MID-MORNING WITH DECENT ISENTROPIC LIFT DEPICTED BY
THE NAM AND RAP ON THE 275K SURFACE...OR MAINLY IN THE 900-800MB
LAYER. WILL LIKELY SEE SNOW AMOUNTS IN THE 1/2 TO 1 INCH RANGE
THROUGH THE DAY WITH THIS WAVE BEFORE IT DEPARTS SOUTHEAST BY THIS
EVENING. OTHERWISE...LOOK FOR HIGHS TODAY IN THE TEENS ACROSS NORTH
CENTRAL WI...TO THE MID/UPPER 20S ELSEWHERE.
SOME LINGERING VERY LIGHT SNOW MAY STILL BE SEEN THIS EVENING EAST
OF THE MISSISSIPPI ON THE TAIL END OF THE PASSING TROUGH...BUT THEN
CLOUDS ARE EXPECTED TO DECREASE AFTER MIDNIGHT FROM SOUTHWEST TO
NORTHEAST AS A WEAK RIDGE OF HIGH PRESSURE BUILDS IN BEHIND THE
DEPARTING WAVE.
MODERATING TEMPERATURES EXPECTED ON FRIDAY AS SOUTHWEST WINDS KICK
IN ON THE BACKSIDE OF THE DEPARTING HIGH AND IN ADVANCE OF LOW
PRESSURE MOVING ALONG THE U.S./CANADIAN BORDER. NAM AND ECMWF
BULLISH WITH 925MB TEMPERATURES WARMING INTO THE 0 TO +5C RANGE
WHEREAS THE GFS IS ONLY IN THE -2 TO +3C RANGE. MODEL CONSENSUS
YIELDS HIGHS IN THE UPPER 20S ACROSS CENTRAL WI...TO THE LOWER 30S
FOR AREAS SOUTHWEST OF THE I-94 CORRIDOR. HOWEVER...SOUTHWEST WINDS
IN THE 10-20MPH RANGE WILL MAKE IT FEEL MORE LIKE THE UPPER TEENS TO
LOWER 20S.
.LONG TERM...(FRIDAY NIGHT THROUGH NEW YEARS DAY)
ISSUED AT 335 AM CST THU DEC 26 2013
WARM AIR ADVECTION WILL CONTINUE FRIDAY NIGHT INTO SATURDAY AS THE
AREA REMAINS IN THE WARM SECTOR OF LOW PRESSURE MOVING ACROSS
SOUTHERN ONTARIO CANADA. LOOK FOR LOWS FRIDAY NIGHT IN THE LOW TO
MID 20S WITH HIGHS ON SATURDAY EXPECTED TO TOP OFF IN THE LOWER AND
MIDDLE 30S. AN ARCTIC COLD FRONT IS THEN SLATED TO DROP THROUGH THE
AREA SATURDAY NIGHT.
WILL HAVE TO KEEP AN EYE ON PRECIPITATION TYPE SATURDAY NIGHT AS THE
GFS BUFKIT SOUNDING HINTING AT LOW LEVEL SATURATION UP TO 800MB WITH
NO ICE PRESENT IN THE CLOUD AS THE FRONT MOVES IN. AS SUCH...ADDED
THE MENTION OF FREEZING DRIZZLE INTO THE WEATHER GRIDS ALONG WITH
THE CHANCE OF LIGHT SNOW. BY EARLY SUNDAY MORNING...IT APPEARS THE
SATURATED COLUMN WILL HAVE ICE PRESENT FOR ALL LIGHT SNOW.
BY SUNDAY MORNING...PLAN ON TEMPERATURES DROPPING INTO THE SINGLE
DIGITS AND TEENS ABOVE ZERO WITH ONLY A 2 TO 3 DEGREE RISE DURING
THE DAY SUNDAY. SOME LIGHT SNOW WILL STILL BE POSSIBLE MAINLY EAST OF
THE MISSISSIPPI RIVER. BRISK NORTHWEST WINDS WILL ADD TO THE CHILL
SUNDAY AS WELL WITH WIND CHILL VALUES FALLING INTO THE -15 TO
-25 DEGREE RANGE ACROSS SOUTHEAST MN/NORTHEAST IA IN
THE AFTERNOON.
VERY COLD WIND CHILLS WILL BE SEEN SUNDAY NIGHT...LASTING THROUGH
TUESDAY MORNING//COLDEST EARLY MONDAY MORNING// AS THE ARCTIC AIR
CONTINUES TO SPILL INTO THE REGION. WIND CHILL HEADLINES WILL LIKELY
BE NEEDED. LOWEST WIND CHILL VALUES MONDAY MORNING COULD BE AS LOW
AS -25 TO -35 DEGREES. SLIGHT MODERATION IN TEMPERATURES MAY BE SEEN
LATER TUESDAY THROUGH WEDNESDAY AS THE HEART OF THE ARCTIC AIR MOVES
MORE INTO THE GREAT LAKES REGION.
EMBEDDED SHORTWAVE TROUGHS EMBEDDED IN THE NORTHWEST FLOW WILL ALSO
GIVE THE AREA PERIODIC LIGHT SNOW CHANCES FROM MONDAY NIGHT THROUGH
WEDNESDAY.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z THURSDAY NIGHT)
ISSUED AT 510 AM CST THU DEC 26 2013
-SN CONTINUES TO FALL ALONG AND NORTH OF A SFC WARM
FRONT...GENERALLY RUNNING NEAR THE MISSISSIPPI RIVER...WITH THE HELP
OF SOME LOW LEVEL ISENTROPIC UPGLIDE. RADAR TRENDS HAVE THIS
SHIFTING AWAY FROM THE TAF SITES. LOW MVFR CIGS ALSO MOSTLY ALONG
AND EAST OF THE FRONT...WITH SATELLITE TRENDS ALSO SUPPORTING
KEEPING THESE LOWER CLOUDS AWAY FROM KRST/KLSE. WILL FOLLOW THESE
TRENDS.
WEAK UPPER LEVEL DISTURBANCE SLATED TO TRACK ACROSS THE NORTHERN
PLAINS AND ACROSS THE LOCAL AREA THIS AFTERNOON. SOME -SN ASSOCIATED
WITH THIS...BUT CURRENT VSBY RESTRICTIONS WERE MOSTLY 4SM OR
GREATER. CIGS WERE A MIX OF MVFR/VFR. RAP/ARW/NAM12 TRENDS SEEM TO
FAVOR A DECREASE IN -SN COVERAGE/INTENSITY AS IT MOVES IN...SO
CONFIDENCE NOT HIGH THAT THERE WILL BE A PERIOD OF IFR CONDITIONS AS
THE SHORTWAVE MOVES THROUGH. SOME MVFR CIGS ARE MORE
LIKELY...ALTHOUGH HOW LONG THESE HANG AROUND IS UNCERTAIN. BUFKIT
SOUNDINGS HOLD ONTO A LOW SATURATION THROUGH MUCH OF TONIGHT...BUT
NOT SOLD THIS IS REALISTIC. WILL GO PESSIMISTIC AND HANG ONTO THE
MVFR CIGS THROUGH THIS EVENING FOR NOW...WITH HIGH VFR CLOUDS
OVERNIGHT.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
SHORT TERM...DAS
LONG TERM....DAS
AVIATION.....RIECK
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
335 AM CST THU DEC 26 2013
.SHORT TERM...(TODAY THROUGH FRIDAY)
ISSUED AT 335 AM CST THU DEC 26 2013
MAIN WEATHER HAPPENINGS WILL BE MORE LIGHT SNOW FOR TODAY...THEN
SOME MODERATION IN TEMPERATURES ON FRIDAY.
WATER VAPOR SATELLITE LOOP COUPLED WITH RAP 500MB ANALYSIS SHOWS THE
NATION DOMINATED BY A LONG WAVE TROUGH OF LOW PRESSURE WITH
NORTHWEST FLOW INTO THE UPPER MISSISSIPPI RIVER VALLEY REGION. AN
EMBEDDED SHORT WAVE TROUGH WAS MOVING INTO THE DAKOTAS EARLY THIS
MORNING...TOWARD OUR FORECAST AREA. MEANWHILE...IR SATELLITE/SURFACE
OBSERVATIONS SHOWING STRATUS CLOUDS ENSHROUDING THE REGION...TRAPPED
UNDER A WEAK RIDGE OF HIGH PRESSURE THAT EXTENDED FROM THE MID AND
UPPER MISSISSIPPI RIVER VALLEY REGIONS INTO NORTHERN MN. RADAR
MOSAIC AND SURFACE OBSERVATIONS SHOWING SOME LIGHT SNOW FLURRY
ACTIVITY ACROSS PORTIONS OF WEST CENTRAL WISCONSIN AND ACROSS CENTRAL
AND NORTHERN MN. LIGHT SNOW WAS FALLING WITH A BIT MORE FERVOR
ACROSS PORTIONS OF ND IN ADVANCE OF THAT MID-LEVEL TROUGH WITH SOME
VISIBILITY RESTRICTIONS IN THE 4-5SM RANGE.
WILL BE WATCHING THAT MID-LEVEL TROUGH MOVE FROM THE DAKOTAS INTO
OUR REGION BY MID-MORNING WITH DECENT ISENTROPIC LIFT DEPICTED BY
THE NAM AND RAP ON THE 275K SURFACE...OR MAINLY IN THE 900-800MB
LAYER. WILL LIKELY SEE SNOW AMOUNTS IN THE 1/2 TO 1 INCH RANGE
THROUGH THE DAY WITH THIS WAVE BEFORE IT DEPARTS SOUTHEAST BY THIS
EVENING. OTHERWISE...LOOK FOR HIGHS TODAY IN THE TEENS ACROSS NORTH
CENTRAL WI...TO THE MID/UPPER 20S ELSEWHERE.
SOME LINGERING VERY LIGHT SNOW MAY STILL BE SEEN THIS EVENING EAST
OF THE MISSISSIPPI ON THE TAIL END OF THE PASSING TROUGH...BUT THEN
CLOUDS ARE EXPECTED TO DECREASE AFTER MIDNIGHT FROM SOUTHWEST TO
NORTHEAST AS A WEAK RIDGE OF HIGH PRESSURE BUILDS IN BEHIND THE
DEPARTING WAVE.
MODERATING TEMPERATURES EXPECTED ON FRIDAY AS SOUTHWEST WINDS KICK
IN ON THE BACKSIDE OF THE DEPARTING HIGH AND IN ADVANCE OF LOW
PRESSURE MOVING ALONG THE U.S./CANADIAN BORDER. NAM AND ECMWF
BULLISH WITH 925MB TEMPERATURES WARMING INTO THE 0 TO +5C RANGE
WHEREAS THE GFS IS ONLY IN THE -2 TO +3C RANGE. MODEL CONSENSUS
YIELDS HIGHS IN THE UPPER 20S ACROSS CENTRAL WI...TO THE LOWER 30S
FOR AREAS SOUTHWEST OF THE I-94 CORRIDOR. HOWEVER...SOUTHWEST WINDS
IN THE 10-20MPH RANGE WILL MAKE IT FEEL MORE LIKE THE UPPER TEENS TO
LOWER 20S.
.LONG TERM...(FRIDAY NIGHT THROUGH NEW YEARS DAY)
ISSUED AT 335 AM CST THU DEC 26 2013
WARM AIR ADVECTION WILL CONTINUE FRIDAY NIGHT INTO SATURDAY AS THE
AREA REMAINS IN THE WARM SECTOR OF LOW PRESSURE MOVING ACROSS
SOUTHERN ONTARIO CANADA. LOOK FOR LOWS FRIDAY NIGHT IN THE LOW TO
MID 20S WITH HIGHS ON SATURDAY EXPECTED TO TOP OFF IN THE LOWER AND
MIDDLE 30S. AN ARCTIC COLD FRONT IS THEN SLATED TO DROP THROUGH THE
AREA SATURDAY NIGHT.
WILL HAVE TO KEEP AN EYE ON PRECIPITATION TYPE SATURDAY NIGHT AS THE
GFS BUFKIT SOUNDING HINTING AT LOW LEVEL SATURATION UP TO 800MB WITH
NO ICE PRESENT IN THE CLOUD AS THE FRONT MOVES IN. AS SUCH...ADDED
THE MENTION OF FREEZING DRIZZLE INTO THE WEATHER GRIDS ALONG WITH
THE CHANCE OF LIGHT SNOW. BY EARLY SUNDAY MORNING...IT APPEARS THE
SATURATED COLUMN WILL HAVE ICE PRESENT FOR ALL LIGHT SNOW.
BY SUNDAY MORNING...PLAN ON TEMPERATURES DROPPING INTO THE SINGLE
DIGITS AND TEENS ABOVE ZERO WITH ONLY A 2 TO 3 DEGREE RISE DURING
THE DAY SUNDAY. SOME LIGHT SNOW WILL STILL BE POSSIBLE MAINLY EAST OF
THE MISSISSIPPI RIVER. BRISK NORTHWEST WINDS WILL ADD TO THE CHILL
SUNDAY AS WELL WITH WIND CHILL VALUES FALLING INTO THE -15 TO
-25 DEGREE RANGE ACROSS SOUTHEAST MN/NORTHEAST IA IN
THE AFTERNOON.
VERY COLD WIND CHILLS WILL BE SEEN SUNDAY NIGHT...LASTING THROUGH
TUESDAY MORNING//COLDEST EARLY MONDAY MORNING// AS THE ARCTIC AIR
CONTINUES TO SPILL INTO THE REGION. WIND CHILL HEADLINES WILL LIKELY
BE NEEDED. LOWEST WIND CHILL VALUES MONDAY MORNING COULD BE AS LOW
AS -25 TO -35 DEGREES. SLIGHT MODERATION IN TEMPERATURES MAY BE SEEN
LATER TUESDAY THROUGH WEDNESDAY AS THE HEART OF THE ARCTIC AIR MOVES
MORE INTO THE GREAT LAKES REGION.
EMBEDDED SHORTWAVE TROUGHS EMBEDDED IN THE NORTHWEST FLOW WILL ALSO
GIVE THE AREA PERIODIC LIGHT SNOW CHANCES FROM MONDAY NIGHT THROUGH
WEDNESDAY.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z THURSDAY NIGHT)
ISSUED AT 1129 PM CST WED DEC 25 2013
VFR CONDITIONS CURRENTLY EXIST AT THE TAF SITES BUT THAT IS ABOUT
TO CHANGE SOON. MVFR STRATUS IS ENCROACHING ON THE TAF SITES FROM
THE WEST NEAR AUSTIN MN...WHICH STRETCHES NORTHWEST TOWARDS ST
CLOUD. THIS STRATUS LOOKS TO MOVE INTO RST BY 0630Z AND LSE BY
0830Z. ALONG WITH THE STRATUS COMES POTENTIAL FOR SNOW...AS NOTED
BY MVFR VISIBILITIES AT ST CLOUD. THESE MVFR VISIBILITIES COULD
OCCUR PERIODICALLY AT RST AND LSE. MODEL FORECASTS SUPPORT THE
PREVIOUS TAF THINKING OF THE BULK OF THE SNOW ENDING BY 12Z.
BETWEEN 12-18Z...RST SHOULD SEE THE MVFR CEILING SCATTER OUT AS
SOME DRIER AIR WORKS IN FROM THE WEST. UNSURE IF THIS DRIER AIR
CAN GET INTO LSE...THOUGH...AS THAT WARM FRONT BECOMES STUCK
NEARBY. THUS HAVE HELD ONTO THE MVFR CEILING AND POTENTIAL FOR
SOME FLURRIES THROUGH THE 12-18Z PERIOD THERE. THEN IN THE
AFTERNOON...ANOTHER WAVE OF LIGHT SNOW REMAINS ON TAP TO MOVE
THROUGH THE TAF SITES WITH UP TO 1 INCH OF ACCUMULATION. APPEARS
THE PEAK TIME FOR SOME IFR VISIBILITIES...PARTICULARLY AT LSE
GIVEN THE LOCATION OF THE WARM FRONT AND EXPECTED TRACK OF THE
SNOW...WOULD OCCUR BETWEEN 20-23Z. SNOW SHOULD BE OUT OF THE TAF
SITES BY 00Z...WITH AN MVFR CEILING PERSISTING THROUGH MUCH OF
TONIGHT AS A WEAK PRESSURE GRADIENT PREVENTS ANY MOVEMENT TO THE
CLOUDS.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
SHORT TERM...DAS
LONG TERM...DAS
AVIATION...AJ
AREA FORECAST DISCUSSION
NWS RENO NV
822 PM PST FRI DEC 27 2013
.UPDATE...
TROUGH PASSING ACROSS NORTHERN NEVADA THIS EVENING IS HAVING LITTLE
EFFECT ON THE STRONG VALLEY INVERSIONS DESPITE EXTENSIVE HIGH
CLOUD COVER. BEHIND THE SYSTEM SKIES WILL CLEAR RAPIDLY BY MIDNIGHT,
ESPECIALLY OVER NORTHEAST CALIFORNIA, THE TAHOE BASIN AND RENO-
CARSON. WINDS WILL REMAIN LIGHT UNTIL SATURDAY AFTERNOON WHEN A
SURFACE HIGH BUILDS INTO NORTHERN NEVADA. THIS WILL LEAD TO A
LIGHT NORTH TO NORTHEAST WIND ACROSS THE WESTERN NEVADA VALLEYS,
WHICH SHOULD BREAK THE INVERSIONS AND ERODE ANY REMAINING FREEZING
FOG.
FREEZING FOG HAS REDEVELOPED WITH VISIBILITY 1/2 OR LESS AT
FALLON, LOVELOCK AND SUSANVILLE THE LAST COUPLE HOURS. WILL ISSUE
A FREEZING FOG ADVISORY FOR PERSHING/CHURCHILL AND EASTERN LASSEN
COUNTIES AS THE FOG WILL REMAIN IN PLACE UNTIL THE NORTH WINDS
ARRIVE TOMORROW AFTERNOON. THE FREEZING FOG SHOULD EXPAND BACK
INTO AREAS IT DID LAST NIGHT, WHICH INCLUDES GERLACH, FERNLEY AND
SLIVER SPRINGS. BRONG
&&
.SYNOPSIS...
AREAS OF FOG AND LOW CLOUDS WILL PERSIST TONIGHT IN SOME LOWER
ELEVATION VALLEYS. OTHERWISE WEAK LOW PRESSURE WILL JUST BRING
HIGH CLOUDS THROUGH SATURDAY. WINDS MAY KICK UP ENOUGH TO MIX OUT
SOME VALLEY INVERSIONS SATURDAY, AND GUSTY NORTHEAST WINDS ARE
LIKELY IN THE SIERRA SATURDAY NIGHT. HIGH PRESSURE WILL BUILD BACK
INTO THE REGION NEXT WEEK WITH NO BIG STORMS ON THE HORIZON.
&&
.PREVIOUS DISCUSSION... /ISSUED 211 PM PST FRI DEC 27 2013/
SHORT TERM...
FOG AND LOW CLOUDS HAVE PERSISTED EAST OF SUSANVILLE AND NEAR
FALLON/LOVELOCK TODAY. HRRR GUIDANCE, WHICH PICKED UP ON FOG NEAR
FALLON, SUGGESTS IT WILL CONTINUE INTO THE EVENING HOURS IN THE NFL
AND CARSON SINK AREAS. HOWEVER FORECAST SOUNDINGS SHOW DRY AIR
MIXING INTO THE LOW LEVELS WHICH ALONG WITH SLIGHTLY INCREASED WINDS
MAY BE ENOUGH TO ERODE FOG/STRATUS. ADMITTEDLY FORECAST
CONFIDENCE IN FOG TRENDS IS ONLY MEDIUM - IT`S ALWAYS A TRICKY
THING TO FORECAST. BASED ON RECENT IMPROVING TRENDS IN VISIBILITY
AT LOL/NFL I`LL CANCEL THE FREEZING FOG ADVISORY, BUT IT IS NOT
OUT OF THE QUESTION WE MAY NEED TO REISSUE LATER THIS EVENING.
ELSEWHERE PATCHY FOG AND LOW CLOUDS ARE POSSIBLE, BUT REDEVELOPMENT
WILL BE LIMITED BY HIGH CLOUDS AHEAD OF APPROACHING SHORTWAVE. THAT
WAVE MAY KICK UP THE WINDS ENOUGH TO MIX OUT INVERSIONS IN ALL BUT
THE LOWEST VALLEYS ON SATURDAY. BEHIND THE WAVE, FLOW ALOFT TURNS NE
AND STRENGTHENS, LEADING TO A PERIOD OF GUSTY WINDS IN THE SIERRA
SATURDAY NIGHT. RIDGE BUILDS BACK IN STARTING SUNDAY, PROBABLY
LEADING TO MORE INVERSIONS AND HAZY CONDITIONS FOR THE VALLEYS EARLY
NEXT WEEK. GFS SHOWS LIGHT PRECIP ALONG THE NV/OR BORDER ASSOCIATED
WITH A PASSING JET STREAK MONDAY NIGHT. CONFIDENCE IN WHETHER THIS
PRECIP WILL IMPACT OUR CWA IS LOW, SO HAVE CONTINUED DRY FORECAST. CS
LONG TERM...TUESDAY THROUGH FRIDAY...
DRY PATTERN WITH LIGHT WINDS AND INVERSION CONDITIONS IS EXPECTED TO
PREVAIL THROUGH NEXT FRIDAY. THE LATEST GFS SHOWS THE RIDGE IN
CLOSER PROXIMITY TO WESTERN NV WHICH WOULD RESULT IN REDUCED
COVERAGE OF CIRRUS ESPECIALLY FOR THURS-FRI. THE ECMWF IS A LITTLE
FLATTER WITH THE RIDGE AND SPREADS HIGH LEVEL MOISTURE OVER THE
REGION AT TIMES, ESPECIALLY NORTH OF I-80. THE ECMWF ALSO BRUSHES A
WEAK SHORTWAVE ACROSS THE FAR NORTH BY NEXT FRIDAY EVENING, BUT
THESE FEATURES HAVE VARIED IN TIMING AND LOCATION WITH EACH RUN SO
WILL NOT ADD ANY PRECIP AT THIS TIME. MAX TEMPS SHOULD REMAIN NEAR
50 DEGREES THRU MOST OF NEXT WEEK. THE INVERSION APPEARS WEAKER ON
TUESDAY SO LOWER ELEVATIONS MAY BE A FEW DEGREES WARMER, OTHERWISE
LITTLE VARIATION IS EXPECTED WITH DAYTIME HIGHS BETWEEN WESTERN NV
AND THE SIERRA VALLEYS. MIN TEMPS WILL BE NEAR SEASONAL NORMALS
MAINLY IN THE LOWER-MID 20S FOR URBAN AREAS, AND TEENS FOR THE
TYPICALLY COOLER VALLEYS IN WESTERN NV AND NEAR THE SIERRA.
FOR THE FOLLOWING WEEK, THE GFS AND SOME OF ITS ENSEMBLE MEMBERS
ATTEMPT TO BREAK DOWN THE PERSISTENT RIDGE NEAR THE WEST COAST,
WITH A FEED OF PACIFIC MOISTURE REACHING THE SIERRA ROUGHLY BETWEEN
JANUARY 7 AND 11. SINCE THESE PROJECTIONS ARE SO FAR INTO THE FUTURE
AND THE ECMWF DOES NOT YET RUN INTO THIS TIME FRAME, THE CONFIDENCE
IN SEEING A CHANGE TO A WETTER PATTERN FOR EASTERN CA-WESTERN NV IS
STILL LOW. MJD
AVIATION...
AT THE MAIN TERMINALS, VFR CONDITIONS WILL PREVAIL THROUGH THIS
WEEKEND AS THE SHORTWAVE PASSAGE TONIGHT SHOULD PREVENT
REDEVELOPMENT OF FREEZING FOG. WINDS WILL GENERALLY REMAIN 10 KT OR
LESS.
A FEW STUBBORN AREAS OF LOW CLOUDS AND FZFG PRODUCING IFR/LIFR CIGS
AND/OR VSBY WILL BE SLOW TO DISSIPATE TONIGHT IN EASTERN LASSEN
COUNTY AFFECTING KSVE, EXTENDING EASTWARD ACROSS THE SMOKE CREEK
DESERT TO NEAR GERLACH. ALSO IMPACTED WILL BE THE WEST CENTRAL NV
BASIN INCLUDING KLOL AND KNFL. SOME LOCATIONS, ESPECIALLY IN
CHURCHILL COUNTY, MAY NOT CLEAR OUT UNTIL MIDDAY SATURDAY. MJD
&&
.REV WATCHES/WARNINGS/ADVISORIES...
NV...FREEZING FOG ADVISORY UNTIL 10 AM PST SATURDAY NVZ004.
CA...FREEZING FOG ADVISORY UNTIL 10 AM PST SATURDAY CAZ071.
&&
$$
FOR MORE INFORMATION FROM THE NATIONAL WEATHER SERVICE VISIT...
HTTP://WEATHER.GOV/RENO (ALL LOWER CASE)
AREA FORECAST DISCUSSION
NWS INDIANAPOLIS IN
230 AM EST SAT DEC 28 2013
.UPDATE...
THE LONG TERM AND AVIATION SECTIONS HAVE BEEN UPDATED BELOW.
&&
.SYNOPSIS...
ISSUED AT 223 AM EST SAT DEC 28 2013
SOUTHWEST WINDS ON THE BACK SIDE OF HIGH PRESSURE WILL ALLOW FOR
ABOVE NORMAL TEMPERATURES TODAY THROUGH MIDDAY SUNDAY. THEN...AN
ARCTIC FRONT WILL SLIDE SOUTHEAST ACROSS CENTRAL INDIANA ON SUNDAY
BRINGING A SMALL CHANCE OF RAIN OR SNOW IN BUT MORE IMPORTANTLY MUCH
COLDER TEMPERATURES. SMALL SNOW CHANCES WILL RETURN MIDWEEK AS
DISTURBANCES MOVE THROUGH IN FAST NORTHWEST FLOW ALOFT.
OTHERWISE...BELOW NORMAL TEMPERATURES WILL CONTINUE THROUGH ALL OF
NEXT WEEK.
&&
.NEAR TERM /TODAY/...
ISSUED AT 223 AM EST SAT DEC 28 2013
MAIN CHALLENGE TO THE NEAR TERM WILL BE TEMPERATURES AS MODELS AND
MOS HAVE BEEN UNDERESTIMATING THE LATEST WARMUP.
MODELS IN GOOD AGREEMENT THAT SURFACE HIGH PRESSURE ACROSS THE
TENNESSEE VALLEY WILL SLIDE EAST TO THE ATLANTIC OCEAN LATE TODAY
WITH SOUTHWEST LOW LEVEL FLOW CONTINUING ACROSS THE AREA. IN
ADDITION...UPPER LOW WILL MOVE NORTHEAST ACROSS NORTHERN TEXAS AND
POLAR FRONT WILL DROP SOUTHEAST ACROSS THE NORTHERN AND CENTRAL
PLAINS AHEAD OF A NORTHERN STREAM UPPER TROUGH. THE DAY SHOULD START
OFF SUNNY WITH MODEL TIME SECTIONS SHOWING A DRY COLUMN.
HOWEVER...HIGH CLOUDS WILL BE INCREASING FROM SOUTH TO NORTH AHEAD
OF THE SOUTHERN SYSTEM. HIGH RESOLUTION NAM12 AND RAP SOUNDINGS WERE
INDICATING INVERSION SHOULD BE IN PLACE AROUND 950 MILLIBARS...SO
WOULD NOT RULE OUT MIXING OF 3K FEET WINDS TO THE SURFACE WITH SOME
GUSTS TO NEAR 20 KNOTS. EITHER WAY...SHOULD SEE TEMPERATURES WARM TO
THE 50S TODAY...A FEW DEGREES WARMER THAN 00Z MOS.
&&
.SHORT TERM /TONIGHT THROUGH MONDAY NIGHT/...
ISSUED AT 223 AM EST SAT DEC 28 2013
MAIN FOCUS TO THE SHORT TERM WILL BE ON TEMPERATURES...ESPECIALLY
SUNDAY AS AN ARCTIC FRONT IS POISED TO DROP SOUTHEAST ACROSS CENTRAL
INDIANA. POPS AND PRECIPITATION TYPE WILL ALSO BE CHALLENGE ON
SUNDAY WITH THE FRONT MOVING THROUGH ALONG WITH A TRAILING UPPER
TROUGH. THE SOUTHERN TROUGH IS ALSO EXPECTED TO BRING RAIN CLOSE
TO...IF NOT ACROSS OUR FAR SOUTH OVERNIGHT SATURDAY NIGHT DEPENDING
ON MODEL OF CHOICE.
00Z GFS AND NAM CLOSE TO THE 12Z ECMWF REGARD HANDLING OF WEAKENING
SOUTHERN PLAINS UPPER LOW AND ALSO WITH THE ARCTIC FRONT.
HOWEVER...MODELS...ESPECIALLY THE GFS HAVE BEEN TRENDING FURTHER
NORTH WITH QPF WITH THE SOUTHERN SYSTEM SATURDAY NIGHT. A BLEND
WOULD WARRANT AT LEAST SMALL POPS AFTER 06Z SUNDAY FOR OUR SOUTHERN
TIER OR TWO. OTHERWISE...SHOULD SEE SKY COVER INCREASE FROM
SOUTH TO NORTH TONIGHT.
MODELS ON SUNDAY SUGGEST THE ARCTIC FRONT WILL BE ACROSS OUR
NORTHWEST COUNTIES SHORTLY AFTER 12Z AND AT OUR EASTERN BORDER
AROUND 18Z. SO...TRIED TO TIME HOURLY TEMPERATURES TO DROP FOLLOWING
THE FRONTAL PASSAGE AND THUS WARMEST TEMPERATURES WILL BE ACROSS THE
EASTERN COUNTIES AND COLDEST NORTHWEST PER 00Z ALLBLEND. WITH DEEPER
SOUTHERN SYSTEM MOISTURE PEELING OF TO THE NORTHEAST AND LITTLE
MOISTURE WITH ARCTIC SYSTEM...KEPT POPS LOW ON SUNDAY. REGARDING
PRECIPITATION TYPE...TRIED TO TIME THE MIX AND CHANGEOVER FROM SNOW
TO RAIN...FOLLOWING CLOSELY BUFKIT BLEND OF CANADIAN PARTIAL
THICKNESSES. THIS WOULD SUGGEST A MIX IN THE NORTHWEST SHORTLY
AFTER 12Z SUNDAY CHANGING TO ALL SNOW DURING THE AFTERNOON. THE
SOUTHEAST SHOULD START OFF AS RAIN AT 12Z AND MIX EARLY AFTERNOON
WITH ALL SNOW LATE AFTERNOON.
WITH THE SOUTHERN SYSTEM WELL NORTHEAST OF THE AREA AND THE NORTHERN
STREAM TROUGH MOISTURE STARVED...WILL NOT MENTION AND POPS SUNDAY
NIGHT.
MONDAY AND MONDAY NIGHT CONTINUE TO LOOK DRY WITH WEAK LOW PRESSURE
SYSTEM JUST TO OUR WEST MONDAY NIGHT MOISTURE STARVED.
00Z ALLBLEND LOOKS LIKE IT IS IN THE BALLPARK FOR TEMPERATURES FOR
THE MOST PART BY SUNDAY NIGHT WITH A FEW TWEAKS NEEDED HERE OR
THERE.
&&
.LONG TERM /TUESDAY THROUGH SATURDAY/...
ISSUED AT 230 AM EST SAT DEC 28 2013
MODELS CONTINUE TO ADVERTISE BROAD CYCLONIC FLOW ACROSS THE EASTERN
PORTION OF THE COUNTRY THROUGH THE LONG TERM PERIOD. ALTHOUGH THIS
MAY LEND ITSELF TO A WAVE OR TWO PROVIDING SOME LIGHT SNOW CHANCES
ACROSS THE AREA...TIMING THESE WAVES...ESPECIALLY THIS FAR OUT...IS
A LOSING PROPOSITION. THUS...FEEL IMPROVEMENTS ARE UNLIKELY TO BE
MADE OVER ALLBLEND INITIALIZATION ASIDE FROM MINOR TWEAKS. WILL
CARRY SLIGHT CHANCE OF SNOW SHOWERS TUESDAY NIGHT INTO WEDNESDAY
NIGHT WITH A POSSIBLE WAVE MOVING THROUGH THE FLOW.
DIFFERENCES ARE LESSENING BETWEEN THE GFS AND EURO...HOWEVER THERE
IS STILL SOME DISCREPANCY ESPECIALLY LATE IN THE PERIOD REGARDING
INTRUSION OF COLD AIR INTO THE LOWER 48 AND RESULTANT TEMPS.
AGAIN...FEEL IMPROVEMENT OVER MODEL BLEND ARE UNLIKELY AND WILL MAKE
FEW CHANGES HERE. WITH BROAD CYCLONIC FLOW...TEMPS SHOULD LARGELY BE
BELOW NORMAL UNTIL PERHAPS LATE IN THE PERIOD DEPENDING ON WHICH
SOLUTION VERIFIES.
&&
.AVIATION /DISCUSSION FOR THE 28/09Z TAF UPDATE/...
ISSUED AT 230 AM EST SAT DEC 28 2013
NO CHANGES NECESSARY. PREVIOUS DISCUSSION FOLLOWS.
ISSUED AT 1115 PM EST FRI DEC 27 2013
VFR THOUGH THE PERIOD.
HIGH CLOUDS WILL CONTINUE ACROSS INDIANA THROUGH THE PERIOD...WITH A
GRADUAL LOWERING AND INCREASE OF MID AND HIGH CLOUDS IN THE LATTER
HALF OF THE TAF PERIOD.
WINDS 1000FT ABOVE GROUND LEVEL AND ABOVE WILL BE AROUND 30-40KT
TONIGHT.
&&
.IND WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
SYNOPSIS...MK
NEAR TERM...MK
SHORT TERM...MK
LONG TERM...NIELD
AVIATION...50/NIELD
VISIT US AT HTTP://WWW.WEATHER.GOV/IND
FOLLOW US ON TWITTER AND YOUTUBE AT:
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AREA FORECAST DISCUSSION...CORRECTED
NWS INDIANAPOLIS IN
228 PM EST FRI DEC 27 2013
.UPDATE...
THE SYNOPSIS...NEAR TERM AND SHORT TERM SECTIONS HAVE BEEN UPDATED
BELOW.
&&
.SYNOPSIS...
ISSUED AT 228 AM EST SAT DEC 28 2013
SOUTHWEST WINDS ON THE BACK SIDE OF HIGH PRESSURE WILL ALLOW FOR
ABOVE NORMAL TEMPERATURES TODAY THROUGH MIDDAY SUNDAY. THEN...AN
ARCTIC FRONT WILL SLIDE SOUTHEAST ACROSS CENTRAL INDIANA ON SUNDAY
BRINGING A SMALL CHANCE OF RAIN OR SNOW IN BUT MORE IMPORTANTLY MUCH
COLDER TEMPERATURES. SMALL SNOW CHANCES WILL RETURN MIDWEEK AS
DISTURBANCES MOVE THROUGH IN FAST NORTHWEST FLOW ALOFT.
OTHERWISE...BELOW NORMAL TEMPERATURES WILL CONTINUE THROUGH ALL OF
NEXT WEEK.
&&
.NEAR TERM /TODAY/...
ISSUED AT 228 AM EST SAT DEC 28 2013
MAIN CHALLENGE TO THE NEAR TERM WILL BE TEMPERATURES AS MODELS AND
MOS HAVE BEEN UNDERESTIMATING THE LATEST WARMUP.
MODELS IN GOOD AGREEMENT THAT SURFACE HIGH PRESSURE ACROSS THE
TENNESSEE VALLEY WILL SLIDE EAST TO THE ATLANTIC OCEAN LATE TODAY
WITH SOUTHWEST LOW LEVEL FLOW CONTINUING ACROSS THE AREA. IN
ADDITION...UPPER LOW WILL MOVE NORTHEAST ACROSS NORTHERN TEXAS AND
POLAR FRONT WILL DROP SOUTHEAST ACROSS THE NORTHERN AND CENTRAL
PLAINS AHEAD OF A NORTHERN STREAM UPPER TROUGH. THE DAY SHOULD START
OFF SUNNY WITH MODEL TIME SECTIONS SHOWING A DRY COLUMN.
HOWEVER...HIGH CLOUDS WILL BE INCREASING FROM SOUTH TO NORTH AHEAD
OF THE SOUTHERN SYSTEM. HIGH RESOLUTION NAM12 AND RAP SOUNDINGS WERE
INDICATING INVERSION SHOULD BE IN PLACE BELOW 950 MILLIBARS...BUT
WOULD NOT RULE OUT MIXING OF SUB 1K FEET WINDS TO THE SURFACE WITH
SOME GUSTS TO NEAR 20 KNOTS. EITHER WAY...SHOULD SEE TEMPERATURES
WARM TO THE 50S TODAY...A FEW DEGREES WARMER THAN 00Z MOS.
&&
.SHORT TERM /TONIGHT THROUGH MONDAY NIGHT/...
ISSUED AT 228 AM EST SAT DEC 28 2013
MAIN FOCUS TO THE SHORT TERM WILL BE ON TEMPERATURES...ESPECIALLY
SUNDAY AS AN ARCTIC FRONT IS POISED TO DROP SOUTHEAST ACROSS CENTRAL
INDIANA. POPS AND PRECIPITATION TYPE WILL ALSO BE CHALLENGE ON
SUNDAY WITH THE FRONT MOVING THROUGH ALONG WITH A TRAILING UPPER
TROUGH. THE SOUTHERN TROUGH IS ALSO EXPECTED TO BRING RAIN CLOSE
TO...IF NOT ACROSS OUR FAR SOUTH OVERNIGHT SATURDAY NIGHT DEPENDING
ON MODEL OF CHOICE.
00Z GFS AND NAM CLOSE TO THE 12Z ECMWF REGARD HANDLING OF WEAKENING
SOUTHERN PLAINS UPPER LOW AND ALSO WITH THE ARCTIC FRONT.
HOWEVER...MODELS...ESPECIALLY THE GFS HAVE BEEN TRENDING FURTHER
NORTH WITH QPF WITH THE SOUTHERN SYSTEM SATURDAY NIGHT. A BLEND
WOULD WARRANT AT LEAST SMALL POPS AFTER 06Z SUNDAY FOR OUR SOUTHERN
TIER OR TWO. OTHERWISE...SHOULD SEE SKY COVER INCREASE FROM
SOUTH TO NORTH TONIGHT.
MODELS ON SUNDAY SUGGEST THE ARCTIC FRONT WILL BE ACROSS OUR
NORTHWEST COUNTIES SHORTLY AFTER 12Z AND AT OUR EASTERN BORDER
AROUND 18Z. SO...TRIED TO TIME HOURLY TEMPERATURES TO DROP FOLLOWING
THE FRONTAL PASSAGE AND THUS WARMEST TEMPERATURES WILL BE ACROSS THE
EASTERN COUNTIES AND COLDEST NORTHWEST PER 00Z ALLBLEND. WITH DEEPER
SOUTHERN SYSTEM MOISTURE PEELING OF TO THE NORTHEAST AND LITTLE
MOISTURE WITH ARCTIC SYSTEM...KEPT POPS LOW ON SUNDAY. REGARDING
PRECIPITATION TYPE...TRIED TO TIME THE MIX AND CHANGEOVER FROM SNOW
TO RAIN...FOLLOWING CLOSELY BUFKIT BLEND OF CANADIAN PARTIAL
THICKNESSES. THIS WOULD SUGGEST A MIX IN THE NORTHWEST SHORTLY
AFTER 12Z SUNDAY CHANGING TO ALL SNOW DURING THE AFTERNOON. THE
SOUTHEAST SHOULD START OFF AS RAIN AT 12Z AND MIX EARLY AFTERNOON
WITH ALL SNOW LATE AFTERNOON.
WITH THE SOUTHERN SYSTEM WELL NORTHEAST OF THE AREA AND THE NORTHERN
STREAM TROUGH MOISTURE STARVED...WILL NOT MENTION AND POPS SUNDAY
NIGHT.
MONDAY AND MONDAY NIGHT CONTINUE TO LOOK DRY WITH WEAK LOW PRESSURE
SYSTEM JUST TO OUR WEST MONDAY NIGHT MOISTURE STARVED.
00Z ALLBLEND LOOKS LIKE IT IS IN THE BALLPARK FOR TEMPERATURES FOR
THE MOST PART BY SUNDAY NIGHT WITH A FEW TWEAKS NEEDED HERE OR
THERE.
&&
.LONG TERM /TUESDAY THROUGH FRIDAY/...
ISSUED AT 216 PM EST FRI DEC 27 2013
ENSEMBLE DATA SUGGEST MEAN UPPER TROUGHING WILL CONTINUE ACROSS THE
EASTERN PARTS OF THE COUNTRY THROUGH LATE NEXT WEEK. APPEARS THE
MAIN PRECIPITATION THREAT DURING THIS PERIOD WILL BE AROUND NEXT
WEDNESDAY INTO THURSDAY AS ENSEMBLES INDICATE A DISTURBANCE WILL
DROP SOUTHEAST FROM THE NORTHERN PLAINS INTO THE LOCAL AREA BY THAT
TIME. THERE IS A QUITE A SPREAD AMONG THE ENSEMBLES AS TO THE
INTENSITY/TRACK OF THIS SYSTEM. MOST OF THE ENSEMBLES ARE
PROGRESSIVE WITH THIS DISTURBANCE...BUT THERE ARE A FEW THAT SUGGEST
SYSTEM MAY BE STRONG ENOUGH TO CUTOFF OVER THE OHIO VALLEY BY LATE
NEXT WEEK. FOR NOW...WILL GO WITH THE WEAKER MORE PROGRESSIVE
SOLUTIONS AND BRING CHANCE POPS FOR SNOW TO THE AREA WEDNESDAY NIGHT
INTO THURSDAY. POTENTIAL FOR LIGHT ACCUMULATIONS EXIST WITH THIS
SYSTEM.
&&
.AVIATION /DISCUSSION FOR 280600Z TAF ISSUANCE/...
ISSUED AT 1115 PM EST FRI DEC 27 2013
VFR THOUGH THE PERIOD.
HIGH CLOUDS WILL CONTINUE ACROSS INDIANA THROUGH THE PERIOD...WITH A
GRADUAL LOWERING AND INCREASE OF MID AND HIGH CLOUDS IN THE LATTER
HALF OF THE TAF PERIOD.
WINDS 1000FT ABOVE GROUND LEVEL AND ABOVE WILL BE AROUND 30-40KT
TONIGHT.
&&
.IND WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...MK
NEAR TERM...MK
SHORT TERM...MK
LONG TERM....JAS
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
223 PM EST FRI DEC 27 2013
.UPDATE...
THE SYNOPSIS...NEAR TERM AND SHORT TERM SECTIONS HAVE BEEN UPDATED
BELOW.
&&
.SYNOPSIS...
ISSUED AT 223 AM EST SAT DEC 28 2013
SOUTHWEST WINDS ON THE BACK SIDE OF HIGH PRESSURE WILL ALLOW FOR
ABOVE NORMAL TEMPERATURES TODAY THROUGH MIDDAY SUNDAY. THEN...AN
ARCTIC FRONT WILL SLIDE SOUTHEAST ACROSS CENTRAL INDIANA ON SUNDAY
BRINGING A SMALL CHANCE OF RAIN OR SNOW IN BUT MORE IMPORTANTLY MUCH
COLDER TEMPERATURES. SMALL SNOW CHANCES WILL RETURN MIDWEEK AS
DISTURBANCES MOVE THROUGH IN FAST NORTHWEST FLOW ALOFT.
OTHERWISE...BELOW NORMAL TEMPERATURES WILL CONTINUE THROUGH ALL OF
NEXT WEEK.
&&
.NEAR TERM /TODAY/...
ISSUED AT 223 AM EST SAT DEC 28 2013
MAIN CHALLENGE TO THE NEAR TERM WILL BE TEMPERATURES AS MODELS AND
MOS HAVE BEEN UNDERESTIMATING THE LATEST WARMUP.
MODELS IN GOOD AGREEMENT THAT SURFACE HIGH PRESSURE ACROSS THE
TENNESSEE VALLEY WILL SLIDE EAST TO THE ATLANTIC OCEAN LATE TODAY
WITH SOUTHWEST LOW LEVEL FLOW CONTINUING ACROSS THE AREA. IN
ADDITION...UPPER LOW WILL MOVE NORTHEAST ACROSS NORTHERN TEXAS AND
POLAR FRONT WILL DROP SOUTHEAST ACROSS THE NORTHERN AND CENTRAL
PLAINS AHEAD OF A NORTHERN STREAM UPPER TROUGH. THE DAY SHOULD START
OFF SUNNY WITH MODEL TIME SECTIONS SHOWING A DRY COLUMN.
HOWEVER...HIGH CLOUDS WILL BE INCREASING FROM SOUTH TO NORTH AHEAD
OF THE SOUTHERN SYSTEM. HIGH RESOLUTION NAM12 AND RAP SOUNDINGS WERE
INDICATING INVERSION SHOULD BE IN PLACE AROUND 950 MILLIBARS...SO
WOULD NOT RULE OUT MIXING OF 3K FEET WINDS TO THE SURFACE WITH SOME
GUSTS TO NEAR 20 KNOTS. EITHER WAY...SHOULD SEE TEMPERATURES WARM TO
THE 50S TODAY...A FEW DEGREES WARMER THAN 00Z MOS.
&&
.SHORT TERM /TONIGHT THROUGH MONDAY NIGHT/...
ISSUED AT 223 AM EST SAT DEC 28 2013
MAIN FOCUS TO THE SHORT TERM WILL BE ON TEMPERATURES...ESPECIALLY
SUNDAY AS AN ARCTIC FRONT IS POISED TO DROP SOUTHEAST ACROSS CENTRAL
INDIANA. POPS AND PRECIPITATION TYPE WILL ALSO BE CHALLENGE ON
SUNDAY WITH THE FRONT MOVING THROUGH ALONG WITH A TRAILING UPPER
TROUGH. THE SOUTHERN TROUGH IS ALSO EXPECTED TO BRING RAIN CLOSE
TO...IF NOT ACROSS OUR FAR SOUTH OVERNIGHT SATURDAY NIGHT DEPENDING
ON MODEL OF CHOICE.
00Z GFS AND NAM CLOSE TO THE 12Z ECMWF REGARD HANDLING OF WEAKENING
SOUTHERN PLAINS UPPER LOW AND ALSO WITH THE ARCTIC FRONT.
HOWEVER...MODELS...ESPECIALLY THE GFS HAVE BEEN TRENDING FURTHER
NORTH WITH QPF WITH THE SOUTHERN SYSTEM SATURDAY NIGHT. A BLEND
WOULD WARRANT AT LEAST SMALL POPS AFTER 06Z SUNDAY FOR OUR SOUTHERN
TIER OR TWO. OTHERWISE...SHOULD SEE SKY COVER INCREASE FROM
SOUTH TO NORTH TONIGHT.
MODELS ON SUNDAY SUGGEST THE ARCTIC FRONT WILL BE ACROSS OUR
NORTHWEST COUNTIES SHORTLY AFTER 12Z AND AT OUR EASTERN BORDER
AROUND 18Z. SO...TRIED TO TIME HOURLY TEMPERATURES TO DROP FOLLOWING
THE FRONTAL PASSAGE AND THUS WARMEST TEMPERATURES WILL BE ACROSS THE
EASTERN COUNTIES AND COLDEST NORTHWEST PER 00Z ALLBLEND. WITH DEEPER
SOUTHERN SYSTEM MOISTURE PEELING OF TO THE NORTHEAST AND LITTLE
MOISTURE WITH ARCTIC SYSTEM...KEPT POPS LOW ON SUNDAY. REGARDING
PRECIPITATION TYPE...TRIED TO TIME THE MIX AND CHANGEOVER FROM SNOW
TO RAIN...FOLLOWING CLOSELY BUFKIT BLEND OF CANADIAN PARTIAL
THICKNESSES. THIS WOULD SUGGEST A MIX IN THE NORTHWEST SHORTLY
AFTER 12Z SUNDAY CHANGING TO ALL SNOW DURING THE AFTERNOON. THE
SOUTHEAST SHOULD START OFF AS RAIN AT 12Z AND MIX EARLY AFTERNOON
WITH ALL SNOW LATE AFTERNOON.
WITH THE SOUTHERN SYSTEM WELL NORTHEAST OF THE AREA AND THE NORTHERN
STREAM TROUGH MOISTURE STARVED...WILL NOT MENTION AND POPS SUNDAY
NIGHT.
MONDAY AND MONDAY NIGHT CONTINUE TO LOOK DRY WITH WEAK LOW PRESSURE
SYSTEM JUST TO OUR WEST MONDAY NIGHT MOISTURE STARVED.
00Z ALLBLEND LOOKS LIKE IT IS IN THE BALLPARK FOR TEMPERATURES FOR
THE MOST PART BY SUNDAY NIGHT WITH A FEW TWEAKS NEEDED HERE OR
THERE.
&&
.LONG TERM /TUESDAY THROUGH FRIDAY/...
ISSUED AT 216 PM EST FRI DEC 27 2013
ENSEMBLE DATA SUGGEST MEAN UPPER TROUGHING WILL CONTINUE ACROSS THE
EASTERN PARTS OF THE COUNTRY THROUGH LATE NEXT WEEK. APPEARS THE
MAIN PRECIPITATION THREAT DURING THIS PERIOD WILL BE AROUND NEXT
WEDNESDAY INTO THURSDAY AS ENSEMBLES INDICATE A DISTURBANCE WILL
DROP SOUTHEAST FROM THE NORTHERN PLAINS INTO THE LOCAL AREA BY THAT
TIME. THERE IS A QUITE A SPREAD AMONG THE ENSEMBLES AS TO THE
INTENSITY/TRACK OF THIS SYSTEM. MOST OF THE ENSEMBLES ARE
PROGRESSIVE WITH THIS DISTURBANCE...BUT THERE ARE A FEW THAT SUGGEST
SYSTEM MAY BE STRONG ENOUGH TO CUTOFF OVER THE OHIO VALLEY BY LATE
NEXT WEEK. FOR NOW...WILL GO WITH THE WEAKER MORE PROGRESSIVE
SOLUTIONS AND BRING CHANCE POPS FOR SNOW TO THE AREA WEDNESDAY NIGHT
INTO THURSDAY. POTENTIAL FOR LIGHT ACCUMULATIONS EXIST WITH THIS
SYSTEM.
&&
.AVIATION /DISCUSSION FOR 280600Z TAF ISSUANCE/...
ISSUED AT 1115 PM EST FRI DEC 27 2013
VFR THOUGH THE PERIOD.
HIGH CLOUDS WILL CONTINUE ACROSS INDIANA THROUGH THE PERIOD...WITH A
GRADUAL LOWERING AND INCREASE OF MID AND HIGH CLOUDS IN THE LATTER
HALF OF THE TAF PERIOD.
WINDS 1000FT ABOVE GROUND LEVEL AND ABOVE WILL BE AROUND 30-40KT
TONIGHT.
&&
.IND WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...MK
NEAR TERM...MK
SHORT TERM...MK
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
NWS MARQUETTE MI
1156 PM EST FRI DEC 27 2013
.SHORT TERM...(THIS EVENING THROUGH SATURDAY)
ISSUED AT 507 PM EST FRI DEC 27 2013
12Z RAOBS/LATEST WV IMAGERY AND RUC ANALYSIS SHOW NW FLOW ALF ACROSS
THE UPR GRT LKS BTWN TROFFING OVER ERN NAMERICA AND UPR RDG IN THE
ROCKIES. SW FLOW/ISENTROPIC ASCENT IN ADVANCE OF SHRTWV DIGGING SEWD
THRU ONTARIO HAS BROUGHT LOTS OF CLDS TO THE CWA. RADAR/SFC OBS
INDICATE SN IS FALLING OVER LK SUP CLOSER TO THE SHARPER ISENTROPIC
ASCENT/SHRTWV AND ACCOMPANYING SFC LO TRACK...BUT DRY WEDGE BTWN
H8-7 SHOWN ON THE 12Z INL RAOB HAS LIMITED THE COVERAGE OF THE SN
FARTHER SW OVER THE LAND CWA. OTRW...SSW LLVL FLOW HAS ADVECTED
WARMER AIR INTO UPR MI...WITH TEMPS THIS AFTN APRCHG ABV 32 AT IWD.
BUT TEMPS REMAIN WELL BLO FRZG OVER THE INTERIOR CENTRAL. THERE IS
SOME CLRG IN MN EXTENDING TOWARD WRN UPR MI WHERE THE LLVL WARMING
HAS BEEN MOST AGGRESSIVE ON THE SRN FLANK OF THE SFC LO SHIFTING
ESEWD NEAR THE MN/CNDN BORDER AND IN ADVANCE OF AN ATTENDANT LO PRES
TROF EXTENDING SWWD INTO THE ERN DAKOTAS. BUT MORE LO CLDS AND SOME
GUSTY NW WINDS FOLLOW THIS TROF FM NDAKOTA INTO MANITOBA/ADJOINING
ONTARIO. FARTHER TO THE W...A STRONG SHRTWV IS MOVING OVER THE WRN
UPR RDG INTO THE PAC NW/BRITISH COLUMBA.
MAIN FCST CONCERNS IN THE SHORT TERM ARE CLD TRENDS/POPS THIS AFTN
RELATED TO THE ONGOING WAD AHEAD OF THE APRCHG DISTURBANCE AND THEN
THE CHC FOR SOME -SN OR EVEN FREEZING DRIZZLE TNGT INTO SAT
FOLLOWING THE TROF PASSAGE.
LATE THIS AFTN/TNGT...BEST CHC FOR SOME WAD SN LATE THIS AFTN INTO
THE EVNG WL BE OVER THE ERN CWA WHERE GUIDANCE SHOWS DEEPER
SATURATION UNDER THE SHARPER ISENROPIC ASCENT DEEPER INTO THE
RETREATING COLD AIR. THE CHC POPS OVER THE ERN CWA WL SHIFT TO THE E
THIS EVNG FOLLOWING PASSAGE OF DISTURBANCE AND END OF WAD/ISENTROPIC
ASCENT. ALTHOUGH THERE WL BE SOME CLRG OVER THE W LATE THIS AFTN
INTO EARLY EVNG PER CURRENT OBS/STLT TRENDS...PASSAGE OF SFC LO PRES
TROF WL BRING A RETURN OF MORE LLVL MSTR/LO CLDS. SOME OF THE MODELS
ALSO GENERATE LGT PCPN OVER MAINLY THE W IN AREAS WHERE WNW FLOW WL
UPSLOPE DESPITE PRESENCE OF LARGER SCALE QVECTOR DVGC/DNVA/WEAK CAD
FOLLOWING THE SHRTWV. FCST SDNGS INDICATE THE MSTR WL BE CONFINED TO
THE LOWEST FEW THOUSAND FEET AND WELL BLO THE DGZ AS INCOMING
AIRMASS IS MARITIME POLAR IN ORIGIN. IN FACT...H85 TEMPS ARE FCST TO
FALL NO LOWER THAN -6C TO -8C EVEN OVER THE TIP OF THE KEWEENAW THRU
12Z SAT...TOO WARM FOR ANY LES. SO RETAINED MENTION OF SOME FREEZING
DRIZZLE AS WELL AS FINE SN/FLURRIES IN THESE UPSLOPE AREAS. AS THE
FLOW AND UPSLOPE WIND COMPONENT DIMINISHES LATE WITH ARRIVAL OF
WEAKER PRES GRADIENT...ANY -FZDZ MAY DIMINISH A BIT AS WELL. WEAKENS
DOWNSLOPE NATURE OF THE EXPECTED LLVL FLOW IN THE WAKE OF THE TROF
MAY RESULT IN SOME CLRG OVER THE SCENTRAL. OVERNGT TEMPS WL BE MUCH
WARMER THAN ON RECENT NGTS GIVEN EXPECTED CLD COVER/MODEST CHILL OF
AIRMASS. THE LOWEST MIN TEMPS ARE MOST LIKELY OVER THE SCENTRAL
WHERE MORE SUSTAINED CLRG SHUD ALLOW FOR A SHARPER TEMP DROP. SOME
FOG MAY DVLP IN THESE AREAS AS WELL WITH RELATIVELY HI SFC DEWPTS.
SAT...FOCUS SHIFTS TO TIMING/IMPACT OF SHRTWV NOW MOVING INTO THE
PAC NW AND ARPCH OF COLD FNT FM THE N. GUIDANCE SHOWS SFC COLD FNT
AND ACCOMPANYING BAND OF H85-7 FGEN SHIFTING SLOWLY S INTO THE NRN
CWA BY EARLY AFTN AS THE FLOW TURNS MORE TO THE NNE WELL TO THE S OF
COLD HI PRES BLDG THRU CENTRAL CANADA. SINCE THE MSTR IS FCST TO
STILL BE RELATIVELY SHALLOW...FREEZING DRIZZLE AS WELL AS SOME LGT
SN/FLURRIES MAY BE THE PTYPE...ESPECIALLY IN UPSLOPE AREAS NEAR LK
SUP. BUT AS THE SHRTWV TO THE W APRCHS LATER IN THE DAY...VIGOROUS
H85-5 QVECTOR CNVGC AND SOME UPR DVGC IN RRQ OF 140KT H3 JET MAX
STREAKING ACRS ONTARIO WL BRING A RETURN OF DEEPER MSTR/HIER POPS
OVER AT LEAST THE NRN TIER. EXPECT THE HIEST TEMPS AOA FRZG OVER THE
SCENTRAL...WHERE THE FNT WL NOT LIKELY PASS UNTIL AFTER 00Z SUN.
.LONG TERM...(SATURDAY NIGHT THROUGH FRIDAY)
ISSUED AT 507 PM EST FRI DEC 27 2013
SAT NIGHT...UPPER LEVEL DIV WITH THE RIGHT ENTRANCE OF THE 130KT
250-300 MB JET THROUGH NRN ONTARIO/WRN QUEBEC AND ASSOCIATED 700
MB FGEN WILL RESULT IN STRONG ENOUGH UPWARD MOTION TO SUPPORT A BAND
OF SNOW FROM NRN MN THROUGH THE NRN LAKES. THE 12Z MODELS ARE IN
GENERAL AGREEMENT WITH POSITION OF HEAVIER PCPN BAND THROUGH NRN
UPPER MI. CONSENSUS QPF AMOUNTS OF 0.15-0.30 WITH SLR VALUES IN THE
15/1 RANGE WOULD GIVE SYNOPTIC SNOW AMOUNTS OF 1 TO LOCALLY 4 INCHES
...GREATEST NORTH. IN ADDITION...CYCLONIC NE TO NNE FLOW INTO NRN
UPPER MI WILL ALSO BRING ADDITIONAL LAKE ENHANCED SNOW AMOUNTS.
SINCE SLR VALUES ONLY CLIMB NEAR 20/1 LATE SAT NIGHT WITH THE
ARRIVAL OF THE COLDER AIR...ADDITIONAL ENHANCEMENT AMOUNTS IN THE 1
TO 4 INCH RANGE WOULD KEEP OVERALL TOTAL GENERALLY IN THE ADVISORY
RANGE OR BELOW 8 INCHES. BELIEVE ONLY A FEW LOCATIONS OVER THE HURON
MTNS COULD APPROACH WARNING CRITERIA OF 8 INCHES DUE TO MORE
PROLONGED FAVORABLE UPSLOPE NE FLOW. IN ADDITION...NRLY WINDS
GUSTING TO 25 TO 30 MPH IN OPEN AREAS NEAR THE LAKE SHORES WILL
PRODUCE BLOWING AND DRIFTING SNOW.
SUN...A TRANSITION FROM LAKE ENHANCED TO PURE LES IS EXPECTED AS THE
DEEPER MOISTURE AND MID-LVL Q-VECT CONV DEPARTS E WITH MOVEMENT OF
LOW PRESSURE SYSTEM. 850 MB TEMPS DROPPING INTO THE -19C TO -22C
RANGE BY 18Z AS 850-700 MB MOISTURE STILL LINGERS OVER AREA WILL
FAVOR CONTINUED MODERATE TO HEAVY LES...ESPECIALLY FOR LOCATIONS
FAVORED BY NRLY UPSLOPE FLOW. EXPECT LES RATES TO GRADUALLY DIMINISH
IN THE AFTERNOON AS WINDS BACK AND INVERSION HEIGHTS DROP TO AROUND
5K FT. WITH EXPECTED SNOWFALL AMOUNTS GENERALLY IN HIGH END OF THE
ADVISORY RANGE...WILL CONTINUE WITH A SPS TO HIGHLIGHT THE POTENTIAL
FOR SIGNIFICANT SNOWFALL. EXPECT THE GREATEST TOTAL ACCUMULATIONS
FROM IRONWOOD THROUGH THE PORCUPINE MOUNTAINS TO ROCKLAND IN THE
WEST AND FROM HERMAN THROUGH THE HURON MOUNTAINS TO NEGAUNEE OVER
THE NORTH CENTRAL. A FEW FAVORED HIGHER TERRAIN LOCATIONS COULD
APPROACH 10 TO 12 INCHES THROUGH THE EVENT.
SUN NIGHT...ENHANCED LOW-LEVEL CONVERGENCE FROM DEVELOPING LAND
BREEZES COULD FAVOR AREAS EAST OF MQT FOR ADDITIONAL MODERATE LES
ACCUMULATION. NAM BUFR SNDGS SHOW FAVORABLE PLACEMENT OF DGZ WITHIN
BEST MODEL OMEGA OF CONVECTIVE BOUNDARY LAYER SO GOOD SNOW GROWTH
AND FLUFFY LES ACCUMULATION EXPECTED. WOULD NOT BE SURPRISED TO SEE
ADVISORY SNOWFALL OF 4 INCHES OR MORE OVER PORTIONS OF ERN
ALGER...NRN SCHOOLCRAFT AND NW LUCE COUNTY WHERE MODELS SHOW BEST
LOW-LVL CONVERGENCE.
MON-WED...AS THE POLAR VORTEX GRADUALLY SHIFTS FROM HUDSON BAY TO
NRN QUEBEC...VERY COLD ARCTIC AIR WILL DOMINATE THE WRN GREAT LAKES.
WITH 850 MB TEMPS DROPPING INTO THE -25C TO -29C RANGE...LES WILL
PERSIST FOR LOCATIONS FAVORED BY NW TO W FLOW. AS TO BE EXPECTED
MODELS STILL SHOWING DIFFERENCES WITH TIMING OF SHORTWAVES MOVING
THROUGH THE REGION AND THUS ACCOMPANYING WIND SHIFTS. THERE MAY
BE PERIODS WHERE THE WINDS ARE LIGHT ENOUGH FOR LAKE INDUCED
TROUGHING TO DOMINATE THE LOW LEVEL FLOW. THE COLD AIRMASS WILL ALSO
FAVOR SMALL SNOWFLAKES THAT WILL LIMIT OVERALL ACCUMULATIONS BUT
STILL LEAD TO LOW VISIBILITIES. OUTSIDE OF THE LES...SEVERE WIND
CHILLS AT TIMES ASE VALUES DROP INTO THE -20 TO -35 RANGE.
THU AND FRI...MODELS SHOW SIGNS OF TRENDING TOWARD LESS AMPLIFIED
PATTERN BY THE END OF THE WEEK WITH WAA DEVELOPING. SFC HIGH
PRESSURE OVER THE REGION SHOULD ENSURE MOSTLY DRY CONDITIONS ON
THURSDAY...EXCEPT FOR SOME LINGERING LIGHT WEST FLOW LES ALONG LAKE
SUPERIOR. EXPECT HIGH TEMPS THU TO REBOUND BACK INTO THE DOUBLE
DIGITS ABOVE ZERO. STRONGER WAA ON FRIDAY AHEAD OF THE NEXT
ADVANCING CLIPPER SYSTEM MAY ALLOW FOR HIGH TEMPS TO CLIMB BACK INTO
THE 20S ESPECIALLY OVER THE EAST HALF OF THE FCST AREA. BOTH THE
ECMWF AND GFS DEVELOP AREA OF LIGHT SNOW NORTH OF LAKE SUPERIOR IN
WAA/ISENTROPIC ASCENT AND SPREAD THIS SNOW ACROSS MAINLY THE EASTERN
AND NORTH CENTRAL FCST AREA. WILL INCLUDE HIGHER CHC POPS IN FRI
FCST FOR THIS SNOW POTENTIAL.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SATURDAY NIGHT)
ISSUED AT 1156 PM EST FRI DEC 27 2013
THE PASSAGE OF A LOW PRESSURE TROUGH SHOULD RESULT IN A WSHFT TO THE
WNW AND THE ARRIVAL OF SOME SHALLOW MSTR. MVFR CONDITIONS WL BE THE
RESULT EXCEPT AT CMX...WHERE MORE PRONOUNCED UPSLOPE COMPONENT WL
BRING ABOUT IFR CONDITIONS WHICH WILL LAST THROUGH THE FORECAST
PERIOD. THERE COULD ALSO BE SOME FLURRIES AND DZ AT IWD AND
ESPECIALLY CMX. MVFR CONDITIONS WILL PERSIST AT IWD UNTIL UPSLOPE NE
WINDS ARRIVE SAT EVENING WHEN CONDITIONS WILL THEN GO TO IFR. AT
SAW...MVFR CONDITIONS WILL LAST INTO SAT AFTERNOON BEFORE IFR
UPSLOPE CLOUDS ARRIVE WHICH WILL LAST INTO SAT EVENING.
&&
.MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 507 PM EST FRI DEC 27 2013
EXPECT SW WINDS UP TO 30 KTS AND SOME FREEZING SPRAY THIS EVENING TO
DIMINISH WITH ARRIVAL OF WEAKER PRES GRADIENT ACCOMPANYING A LO PRES
PASSAGE. STRONGER N WINDS AND SOME FREEZING SPRAY WILL REDEVELOP ON
SAT FOLLOWING THE PASSAGE OF ANOTHER COLD FRONT AND AS ARCTIC AIR
SURGES S IN ADVANCE OF HI PRES BUILDING INTO SCENTRAL CANADA. AS
ARCTIC AIR FLOWS S INTO THE AREA BEHIND FRONT AND NE GRADIENT
TIGHTENS BEHIND LOW PASSING TO SOUTH LOOK FOR A PERIOD OF GALES TO
DEVELOP OVER THE WEST AND NCNTRL SAT NIGHT SO HAVE ISSUED A GALE
WATCH FOR THIS POTENTIAL. OTHERWISE NE WINDS TO 30KT WILL BE COMMON
SAT NIGHT FOR THE REST OF THE LAKE BACKING TO THE NORTH ON SUNDAY.
HEAVY FREEZING SPRAY IS STILL EXPECTED OVER MUCH OF THE LAKE SAT
NIGHT INTO MONDAY. IT APPEARS THAT THE ARCTIC AIR WILL SETTLE INTO
THE UPPER LAKES FOR AN EXTENDED STAY MUCH OF NEXT WEEK...ALTHOUGH NO
GALES APPEAR EVIDENT AT THIS POINT.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
HEAVY FREEZING SPRAY WARNING FROM 1 AM SUNDAY TO 7 AM EST MONDAY
FOR LSZ265-267.
HEAVY FREEZING SPRAY WARNING FROM 1 AM SUNDAY TO 7 PM EST MONDAY
FOR LSZ266.
GALE WATCH FROM SATURDAY EVENING THROUGH SUNDAY MORNING FOR
LSZ162-263-264.
HEAVY FREEZING SPRAY WARNING FROM 7 PM EST /6 PM CST/ SATURDAY
TO 1 AM EST /MIDNIGHT CST/ MONDAY FOR LSZ162-263-264.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...KC
LONG TERM...VOSS
AVIATION...07
MARINE...VOSS/KC
AREA FORECAST DISCUSSION...UPDATED
NWS RENO NV
641 AM PST SAT DEC 28 2013
.UPDATE...
QUICK UPDATE THIS MORNING TO INCREASE THE COVERAGE OF FREEZING FOG
IN WESTERN NEVADA, BASED OFF OF LATEST IR IMAGERY. LOOKS LIKE A
GOOD AMOUNT OF FOG HAS CREPT DOWN INTO THE SPANISH SPRINGS VALLEY
NORTH OF SPARKS, AS WELL AS INTO THE MASON VALLEY AND AS FAR SOUTH
AS HAWTHORNE AND WALKER LAKE. THE AREAS OF HIGHEST CONCERN REMAIN
PERSHING, CHURCHILL, AND EASTERN LASSEN COUNTIES WHERE THE
FREEZING FOG HAS REMAINED THROUGHOUT THE NIGHT AND IS MOST LIKELY
TO HAVE DEPOSITED THE MOST RIME ICE ONTO THOSE AREA ROADS. THAT
BEING SAID, ANY DRIVERS ENCOUNTERING DENSE FREEZING FOG THIS
MORNING SHOULD BE AWARE OF POTENTIAL ICY ROAD CONDITIONS.
THE LATEST HRRR MODEL IS SHOWING FOG OVER THE CARSON AND HUMBOLDT
SINKS ALL DAY LONG TODAY, SO THE DAY SHIFT WILL NEED TO MONITOR
TRENDS AND MAY NEED TO EXTEND THE ADVISORY FOR FREEZING FOG IN
FALLON AND LOVELOCK PAST 10 AM. HOON
&&
.PREVIOUS DISCUSSION... /ISSUED 240 AM PST SAT DEC 28 2013/
SYNOPSIS...
AREAS OF FOG AND LOW CLOUDS WILL PERSIST THIS MORNING IN SOME LOWER
ELEVATION VALLEYS. OTHERWISE...WEAK LOW PRESSURE WILL JUST BRING
HIGH CLOUDS THROUGH SATURDAY. WINDS MAY KICK UP ENOUGH TO MIX OUT
SOME VALLEY INVERSIONS TODAY, AND GUSTY NORTHEAST WINDS ARE LIKELY
IN THE SIERRA SATURDAY NIGHT. HIGH PRESSURE WILL BUILD BACK INTO THE
REGION NEXT WEEK WITH NO BIG STORMS ON THE HORIZON.
SHORT TERM...
THE EVER PERSISTENT FREEZING FOG THAT REFUSED TO DISSIPATE
YESTERDAY WILL FINALLY BREAK LATE THIS MORNING BY EARLY AFTERNOON
AS A WEAK AND DRY FRONTAL BOUNDARY MOVES THROUGH THE NEVADA
INTERIOR. WHILE THIS IS A COLD FRONT, TEMPERATURES WILL ACTUALLY
WARM FOR VALLEYS THAT HAVE BEEN PERSISTENTLY FOGGED IN. WINDS
SHOULD SHIFT OUT OF THE NORTH AROUND NOON TODAY WITH ONLY LIGHT
GUSTS FOR THE VALLEY SURFACES. HOPEFULLY, THE WINDS WILL BE
SUFFICIENT TO CLEAR MOST OF THE POLLUTION THAT HAS SETTLED IN
WESTERN NEVADA VALLEYS. THE THERMAL GRADIENT IS NOT THAT STRONG
SUGGESTING THAT THE VALLEYS MAY NOT BE COMPLETELY SCOURED OUT.
HOWEVER, WILL REMAIN OPTIMISTIC THAT OVERALL AIR QUALITY WILL
IMPROVE.
RIDGE WINDS WILL BECOME GUSTY UP TO ABOUT 50 MPH BY THIS
AFTERNOON AS THE WINDS BECOME MORE NORTHEASTERLY TO EASTERLY BY
EARLY SUNDAY MORNING. OTHERWISE, THE ONLY NOTABLE FORECAST ELEMENT
WILL BE AN INCREASE IN CLOUD COVER ACCOMPANYING THE FRONT THEN
LINGERING THROUGH MONDAY. BOYD
LONG TERM...TUESDAY THROUGH FRIDAY...
RIDGE OF HIGH PRESSURE REMAINS ALONG THE WEST COAST THROUGH NEXT
WEEK WITH GENERALLY LIGHT WINDS. MODELS ARE SHOWING SOME INCREASING
MOISTURE ON TUESDAY, ASSOCIATED WITH SOME WARM AIR ADVECTION ALOFT.
THIS COULD POTENTIALLY BRING SOME LIGHT SHOWERS TO THE REGION,
ESPECIALLY NORTH OF HIGHWAY 50, ALTHOUGH IT WILL MOSTLY BE JUST
VIRGA AND INCREASED CLOUDS AS IT WOULD HAVE TO OVERCOME A VERY DRY
BOUNDARY LAYER. THE INCREASED CLOUDS WILL ALSO TEMPER THE WARMING ON
TUESDAY, SO LOWERED TEMPS SEVERAL DEGREES IN THE VALLEYS.
AFTER TUESDAY, WE STAY IN A DRY PATTERN THROUGH THE REST OF THE WEEK
AND INTO THE FOLLOWING WEEKEND. THERE IS SOME POTENTIAL OF A
SHORTWAVE DROPPING INTO THE PAC NW LATE FRIDAY, ACCORDING TO THE
ECMWF AND GEM, ALTHOUGH FORECASTER CONFIDENCE IS LOW REGARDING THIS
FEATURE. HIGH TEMPERATURES WILL GENERALLY REMAIN AROUND 50 DEGREES,
WITH LITTLE VARIATION BETWEEN THE DESERT VALLEYS AND SIERRA VALLEYS.
THERE IS A SLIGHT BIT OF HOPE FOR A BREAKDOWN OF THIS PERSISTENT DRY
PATTERN SOMETIME AROUND THE SECOND WEEK OF JANUARY, BUT FORECASTER
CONFIDENCE REMAINS VERY LOW AT TIME. HOON
AVIATION...
A FEW AREAS OF IFR FREEZING FOG REMAIN THROUGH 18Z THIS MORNING,
ESPECIALLY AROUND KLOL, KNFL, AND KSVE. A WEAK SHORTWAVE MOVING
THROUGH THE REGION TODAY WILL REDUCE FOG POTENTIAL TONIGHT. WINDS
WILL BECOME GUSTY FROM THE EAST-NORTHEAST OVER THE SIERRA RIDGES
TONIGHT INTO SUNDAY. OTHERWISE, VFR CONDITIONS ARE EXPECTED THROUGH
THE WEEKEND. POTENTIAL FOR VALLEY FOG RETURNS AGAIN SUNDAY NIGHT
INTO MONDAY MORNING. HOON
&&
.REV WATCHES/WARNINGS/ADVISORIES...
NV...FREEZING FOG ADVISORY UNTIL 10 AM PST THIS MORNING NVZ004.
CA...FREEZING FOG ADVISORY UNTIL 10 AM PST THIS MORNING CAZ071.
&&
$$
FOR MORE INFORMATION FROM THE NATIONAL WEATHER SERVICE VISIT...
HTTP://WEATHER.GOV/RENO (ALL LOWER CASE)
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
956 AM CST SAT DEC 28 2013
.DISCUSSION...
339 AM CST
THE ROLLER COASTER RIDE IN TEMPERATURES THIS FINAL WEEKEND OF 2013 IS
THE PRIMARY FORECAST CHALLENGE...WITH A STRIKING 50 DEGREE
DIFFERENCE FROM HIGHS THIS AFTERNOON TO MORNING TEMPERATURES ON
MONDAY EXPECTED. THE UPCOMING SHARP DIP ON OUR RIDE WILL TAKE US
INTO THE FIRST DAYS OF THE NEW YEAR WITH ANOMALOUS COLD SET FOR
NEXT WEEK. TEMPERATURES AND SNOW POTENTIAL IN THAT PATTERN WERE
THE NEXT CHALLENGES WITH THIS FORECAST.
TODAY...SOUTHWEST FLOW CONTINUES OVER THE AREA THIS MORNING WITH
TEMPERATURES AT OR ABOVE FREEZING AT 330 AM ACROSS MOST CWA
COMMUNITIES. THIS MILD STARTING POINT OFFERS A NICE SPRINGBOARD FOR
TEMPERATURES ALREADY SET TO BE THE WARMEST SINCE DECEMBER 4TH. AS
LOW PRESSURE FROM ND EARLY THIS MORNING MOVES TO WESTERN WI BY EARLY
EVE...A WARM SECTOR WITH SOUTHWEST FLOW WILL BE IN PLACE ACROSS THE
AREA. LITTLE IN THE WAY OF CLOUDS IS SEEN ON MORNING SATELLITE AND
UPPER LEVEL SUPPRESSION IS EVEN INDICATED ON WATER VAPOR WHICH LOOKS
TO REMAIN THROUGH MIDDAY FURTHER ALLOWING FOR A SUN-FILLED SKY. THE
SNOW PACK PROVIDED A 10 TO AS MUCH AS 15 DEGREE TEMPERATURE GRADIENT
ACROSS THE FORECAST AREA YESTERDAY AND WOULD EXPECT NEAR THAT TODAY.
HAVE GUIDED BY YESTERDAYS LAST VISIBLE IMAGERY AS WELL AS NOHRSC
DATA FOR SNOW COVER INFLUENCE. THE 00Z/06Z NAM LOOKS ABOUT 1-1.5C
WARM ON 925MB TEMPS BASED ON LAST EVES SOUNDINGS...SO HAVE GONE
CLOSER TO THE 8-9C PROJECTED OVER THE AREA BY MOST OTHER GUIDANCE.
CLIMATOLOGY SUGGESTS LOW-MID 50S WITH THIS AS AN AVERAGE...AND EVEN
LOCAL ON-THE-FLY RESEARCH DONE EARLIER IN THE WEEK BY A COLLEAGUE
INDICATED 54 AS AN AVERAGE AT ORD WITH THESE 925MB TEMPS AND SW FLOW.
IT LOOKS LIKE AREAS JUST EAST OF THE SNOW PACK...INCLUDING
CHICAGO...WILL STILL HAVE SOME MODIFICATION OF THE SW FLOW BASED ON
PARCEL TRAJECTORIES OVER SNOW PACK SO HAVE UNDERCUT THAT 54 BY A
HANDFUL OF DEGREES...BUT DO EXPECT THE 50 DEGREE ISOTHERM TO BISECT
THE METRO AREA WITH THE SOUTH SIDE WARMING THE MOST. EVEN THE 13KM
RAP FORECAST TEMPS THROUGH THIS AFTERNOON INDICATE THIS TYPE OF
TREND. AREAS SOUTH OF INTERSTATE 80 AND EAST OF ILLINOIS 47 SHOULD
BE ABLE TO REALIZE THOSE MID 50S.
TONIGHT INTO SUNDAY...HAVE GUIDED WITH THE SLIGHTLY FASTER NAM
TIMING ON THE COLD FRONTAL PASSAGE...BUT ALL IN ALL GUIDANCE/MOS IS
BASICALLY WITHIN 3 HRS OF FROPA FOR ANY ONE POINT. THE UPPER WAVE OF
THIS SYSTEM IS WELL-DEFINED ON WATER VAPOR OVER MT EARLY THIS
MORNING AND ALREADY 160M HEIGHT FALLS WERE OBSERVED AT 500MB WITH
IT LAST NIGHT. THE FRONT IS DRIVEN BY THE COLLECTIVE STRONG COLD
AIR ADVECTION...THICKNESS FALLS...AND SURFACE PRESSURE RISES AND
SHOULD HAVE GOOD MOMENTUM TO DRIVE IT. THE MERCURY WILL DROP
THROUGH THE DAY SUNDAY WITH WIND CHILLS LIKELY TO FALL BELOW ZERO
ACROSS NORTH CENTRAL IL DURING THE AFTERNOON. OVERCAST STRATOCU IS
EXPECTED IMMEDIATELY IN THE WAKE OF FROPA AS INDICATED BY FORECAST
MODEL SOUNDINGS. THE DEPTH OF THE SATURATED LAYER WITH RESPECT TO
ICE IS FAIRLY SHALLOW AT THE TOP OF THE MIXED LAYER...AND OMEGA IS
NOT FORECAST TO BE THE BEST FOR WIDESPREAD SNOW SHOWERS.
HOWEVER...UPPER LEVEL FORCING ALONG THE 650-850MB BAROCLINIC ZONE
BEHIND THE FRONT MAY ALSO HELP FOR SOME LIGHT SNOW MORE SO INTO
THE AFTERNOON. GIVEN THE DEGREE OF COLD AIR ADVECTION...THIS
CONTINUES TO LOOK LIKE A POST-FRONTAL AIR MASS THAT WOULD HAVE SOME
LIGHT SNOW/SNOW SHOWERS...WITH BEST CHANCES IN THE NORTHERN
FORECAST AREA. SO HAVE CONTINUED THAT IN THE FORECAST ON SUNDAY
AND EARLY SUNDAY EVE. LAKE EFFECT TRAJECTORIES CONTINUE TO FAVOR
JUST EAST OF OUR NW INDIANA COUNTIES FOR ANY SHOWERS DURING
SUNDAY NIGHT. TEMPERATURES SUNDAY NIGHT ARE STILL FORECAST TO HEAD
BELOW ZERO ACROSS A LARGE PART OF THE IL FORECAST AREA.
WIND CHILL HEADLINE POTENTIAL...SUSTAINED WIND SPEEDS AROUND 15
MPH TO START SUNDAY EVE WILL ONLY VERY GRADUALLY DIMINISH DURING
SUNDAY NIGHT. WHILE DEFINITE ADVISORY CRITERIA WILL BE MET...AT
THIS POINT WARNING CRITERIA IS NOT FORECAST ALTHOUGH IT MAY BE
CLOSE IN NORTH CENTRAL IL SUNDAY NIGHT INTO EARLY MONDAY. SO HAVE
NOT OPTED ANY WATCH AT THIS TIME. IN ADDITION...WIND CHILL
ADVISORY CRITERIA MAY BE CLOSE AGAIN TUESDAY NIGHT INTO EARLY
WEDNESDAY.
NEXT WEEK...A NORTHWEST JET AROUND 150KT WILL RE-INTENSIFY THE
HUDSON BAY TROUGH WITH 500MB HEIGHTS AT ITS CENTER FORECAST TO DIP
TO AN EYE-OPENING LOW 481DM. THIS WILL ALLOW FOR ESTABLISHED
NORTHWEST FLOW OVER THE MIDWEST AND WITH THAT ONCE AGAIN COMES
SEVERAL SMALL MID-LEVEL PERTURBATIONS CAPABLE OF SNOW. AS THIS
PAST WEEK SHOWED...THESE ARE CHALLENGING TO FORECAST SPECIFICS
WELL IN ADVANCE. OVERALL...THE PATTERN WILL BE FAVORABLE FOR THESE
TO BRING MINOR ACCUMULATIONS OVER THE PATH THEY TAKE...JUST GIVEN
A DEEPER DENDRITIC GROWTH ZONE ABLE TO BE SATURATED WITH EACH
IMPULSE. MONDAY NIGHT AND AGAIN TUESDAY NIGHT AT THIS TIME ARE THE
AVERAGES IN GUIDANCE FOR POTENTIALLY LIGHT ACCUMULATING
SNOW...BUT AGAIN QUITE A BIT COULD CHANGE WITH THESE. FOR
TEMPERATURES...EACH IMPULSE LOOKS TO KEEP THE COLD AIR IN PLACE
WITH ONLY VERY MINIMAL WARM AIR ADVECTION IN ADVANCE OF ANY OF
THESE. HAVE UNDERCUT A MODEL MEAN SLIGHTLY OVER THE NORTHWEST
FORECAST AREA WHERE SNOW PACK STILL SHOULD HAVE GREATER INFLUENCE
TO KEEP TEMPS DOWN. ALL IN ALL THOUGH VERY LITTLE CHANGES TO
PREVIOUS FORECAST FOR NEXT WEEK.
MTF
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 16Z...
*ARRIVAL TIME OF ARCTIC FRONT LATE OVERNIGHT SUN.
*INCREASING CHANCE FOR -SN DURING PREDAWN SUN...BECOMING LIKELY BY
MID MORNING.
TRS/RATZER
//DISCUSSION...UPDATED 12Z...
NO PROBLEMS UNTIL LATE IN THE FORECAST PERIOD WHEN AND ARCTIC
FRONT SWEEPS ACROSS THE LOCAL AREA DURING LATE OVERNIGHT TONIGHT
TO EARLY SUN MORNING TIME FRAME.
MODELS TEND TO GRADUALLY VEER WINDS RATHER THAN DEPICT A WELL
DEFINED WIND SHIFT BUT USING SURFACE WIND STREAMLINES MODELS ARE
SIMILAR IN FROPA AROUND 11Z BUT DO NOT EXPECT WIND TO BECOME VERY
GUSTY OUT OF THE NW UNTIL LATER IN THE MORNING WHEN THE MID LEVEL
TROUGH PASSES BY.
OTHER PROBLEMS ARE TIMING THE ARRIVAL OF STRATOCUMULUS BEHIND THE
FRONT AS WELL AS WHEN -SN BECOMES LIKELY. MODEL AGAIN SIMILAR IN
LOWER LEVEL RH PROGS BRING STRATOCUMULUS SOON AFTER THE FRONT
PASSES...LOWERING BASES INTO MVFR DURING BY MID MORNING. BASED ON
MODEL QFP FIELDS NO PRECIP S OF THE WI BORDER BEFORE 12Z. WITH
BOTH THE 12Z AND 18Z PROGS VERY SIMILAR IN THE PLACEMENT OF
PRECIP. EXTRAPOLATION OF THE LEADING EDGE OF 0.01 BETWEEN 12Z AND
18Z BRINGS IN -SN AROUND MID MORNING.
TRS
//ORD AND MDW CONFIDENCE...UPDATED 16Z...
*HIGH ALL ELEMENTS BUT MEDIUM ON ARRIVAL TIME OF COLD
FRONT...MVFR AND -SN ARRIVE OVERNIGHT/EARLY SUN MORNING.
TRS/RATZER
//OUTLOOK FOR ORD/MDW FOR 00Z MONDAY-12Z SATURDAY...UPDATED 12Z...
SUNDAY NIGHT...MVFR CIGS...BECOMING VFR OVERNIGHT.
MONDAY...VFR...BECOMING MVFR MON NIGHT WITH A CHANCE OF SNOW.
TUESDAY...MVFR CIGS. CHANCE OF LIGHT SNOW.
WEDNESDAY...MVFR CIGS. CHANCE OF LIGHT SNOW.
THURSDAY...VFR.
FRIDAY...VFR. SLIGHT CHANCE OF SNOW SHOWERS.
TRS
&&
.MARINE...
441 AM CST
A STRONG SW FLOW WILL DEVELOP TODAY AS LOW PRESSURE MOVES SE FROM
ND TO WI. HOWEVER...WITH STRONG WARM AIR ADVECTION CONTINUING AND
THE WATER IN THE LOWER TO MID 30S F THE SURFACE WILL BE DECOUPLED
FROM THE STRONG FLOW JUST ABOVE THE BASE OF THE TEMPERATURE
INVERSION. NORTHWEST GALES OF 35 TO 40 KT WILL ARRIVE DURING THE
PREDAWN HOURS OF SUNDAY ON THE N END OF LAKE MICHIGAN...AND THE
S END BY MID MORNING SUNDAY AS THE LOW MOVES E ACROSS FAR N LAKE
MI INTO NORTHERN LOWER MI OVERNIGHT AND THE TRAILING COLD FRONT
SWEEPS SE ACROSS THE LAKE OVERNIGHT TONIGHT AND EARLY SUN MORNING.
ARCTIC AIR WILL OVERSPREAD THE UPPER GREAT LAKES BEHIND THE COLD
FRONT RESULTING IN A VERY UNSTABLE CONDITION DUE TO THE LARGE
CONTRAST BETWEEN WATER AND AIR TEMPERATURE. THIS WILL RESULT IN
EFFICIENT TRANSFER OF STRONG WINDS RIGHT DOWN TO THE LAKE
SURFACE. IN ADDITION...STRONG HIGH PRESSURE WILL BE BUILDING SE
FROM S SASKATCHEWAN ACROSS THE N AND CENTRAL PLAINS OVERNIGHT
TONIGHT AND SUN. WINDS WILL GRADUALLY DIMINISH SUN NIGHT AS THIS
HIGH MOVES TO THE UPPER AND MID MS VALLEY.
A GALE WARNING IS UP FOR ALL THE OPEN WATERS OF THE LAKE...STARTING
IN THE PREDAWN HOURS ON THE N...AND MID MORNING ON THE S. A GALE
WARNING IS ALSO IN EFFECT FOR THE NEARSHORE FROM GARY TO MI CITY .
A SMALL CRAFT ADVISORY WILL LIKELY BE NEEDED FROM WINTHROP HARBOR
TO GARY DURING SUN AND SUN NIGHT.
TRS
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...GALE WARNING...LMZ261-LMZ362-LMZ364-LMZ366-LMZ563-LMZ565...4 AM
SUNDAY TO 6 PM SUNDAY.
GALE WARNING...LMZ080-LMZ567-LMZ669-LMZ671-LMZ673-LMZ675-LMZ744-
LMZ745-LMZ777-LMZ779-LMZ868-LMZ870-LMZ872-LMZ874-LMZ876-
LMZ878...9 AM SUNDAY TO 9 PM SUNDAY.
&&
$$
VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE)
FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
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WWW.YOUTUBE.COM/NWSCHICAGO
[top]
Area Forecast Discussion
National Weather Service Lincoln IL
937 AM CST Sat Dec 28 2013
.DISCUSSION...
ISSUED 936 AM CST Sat Dec 28 2013
Temperature trends remain the primary forecast concern for today.
Already have widespread upper 30s and lower 40s over the CWA, even
in the snow covered northwest. Most of the model guidance
continues to run too cool. Have favored the HRRR which looks good
in most areas, except it also is too cool where the snow is
currently in place. Morning cooperative weather observations, as
well as visible satellite imagery, show 1-2 inches still on the
ground early this morming across Knox, Stark and western
Marshall Counties. Should still get in the upper 40s there, but
50-55 will be common elsewhere this afternoon. Have sent updated
grids to reflect the latest trends, but the worded forecasts still
look good.
Geelhart
&&
.AVIATION...
ISSUED 545 AM CST Sat Dec 28 2013
VFR conditions will prevail in central and eastern Illinois today
and into much of the overnight hours. A southwest surface wind
will remain in the 10-15 knot range as the pressure gradient
changes little throughout the day. Initial information from this
morning`s KILX upper air sounding indicated marginal wind speeds
for low level wind shear. Will not mention in the TAFs at this
point since it is still below LLWS criteria, and little change is
anticipated this morning.
High and mid level clouds from the lower Mississippi River valley
will continue to spread northward. Cirrus ceilings will reach
central IL TAF sites early this evening, along with scattered mid
clouds from 10-15 kFT. A quickly approaching cold front from the
northwest will usher in much colder air and shift the wind to the
northwest just before daybreak Sunday in central IL, between 10-12Z.
MVFR ceilings are also likely at and just behind the cold front,
so will introduce these into the forecast from KBMI-KSPI and
points west.
Miller
&&
.PREV DISCUSSION...
ISSUED 330 AM CST Sat Dec 28 2013
SHORT TERM...Today through Monday
00Z short range models are in good agreement through Monday and
will use a blend. Polar vortex over northeast Canada through mid
week to have northern stream short waves passing through the
Midwest and Great Lakes region around Monday night into Tue night
and another one around Thu. Models differ with timing and
placement of these features and will use a blend of models and
previous forecast for this package.
Another mild day today expected across central and southeast IL
with some areas getting in the low to mid 50s. Then an arctic cold
front near the US/Canadian border to pass se through IL later
tonight into Sunday morning. Just a small chance of light
precipitation Sunday (mainly light snow or flurries). More
importantly, this front to usher in another arctic airmass Sunday
and Sunday night and will stick around through Thursday night.
Early morning surface map shows 1030 mb high pressure over the
southeast states while 1004 mb low pressure along the MT/ND and
Canadian border. SW winds over IL keeping milder temps in the mid
to upper 30s early this morning with nearly clear skies. 568 dm
500 mb low over west Texas has high/cirrus clouds spreading
northward into the mid MS valley including far southern IL and KY
early this morning. Some of these thin high clouds to spread into
central and especially southeast IL today with a fair amount of
sunshine still expected today. SW winds 10-15 mph and gusts 15-20
mph to boost highs in the low to mid 50s this afternoon, expected
upper 40s nw of the IL river where a light snow cover remains
especially over Knox and Stark counties.
Arctic cold front near the US/Canadian border to push se through
the IL river valley late tonight and have temps dropping into the
upper teens and lower 20s nw of the IL river by dawn while milder
low to mid 30s over eastern/se IL for lows tonight. Clouds to
increase during tonight with a fair amount of clouds Sunday as
arctic front pass se through eastern/se IL sunday morning. Not
much moisture to work with so think mainly small chance of very
light precipitation Sunday behind the front in from of light snow
or flurries, though light rain possible Sunday morning over se IL.
Highs Sunday in the morning range from the lower 20s nw of the IL
river to the upper 30s and lower 40s in southeast IL with falling
temps through the day behind the arctic front.
Very cold air advects into IL Sunday night into Monday with wind
chills likely getting to 15 to 20 below zero north of I-72
overnight Sunday night into Monday morning and will likely need a
wind chill advisory as event gets closer. Lows Sunday night to be
in the single digits below from I-55 nw with highs Monday from 8-14
north of I-72.
LONG TERM...Monday night through Friday
Very cold conditions expected to continue Monday night through Thu
night with polar vortex in northeast Canada and strong upper level
trof over the region and reinforced on Thursday. A northern stream
short wave approaches northern counties during Monday night with
slight chance of light snow or flurries and gets further into
central IL Tue and Tuesday night before exiting on Wed. Not
expecting much accumulations of snow at this point in dry airmass.
Could be another chance of flurries on Thursday with strong upper
level trof and possible short wave moving thru region. Large upper
level trof shifts east of IL Fri/Sat with temps moderating closer
to normal with dry conditions expected.
07
&&
.ILX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS INDIANAPOLIS IN
922 AM EST SAT DEC 28 2013
.UPDATE...
THE AVIATION SECTION HAS BEEN UPDATED BELOW.
&&
.SYNOPSIS...
ISSUED AT 223 AM EST SAT DEC 28 2013
SOUTHWEST WINDS ON THE BACK SIDE OF HIGH PRESSURE WILL ALLOW FOR
ABOVE NORMAL TEMPERATURES TODAY THROUGH MIDDAY SUNDAY. THEN...AN
ARCTIC FRONT WILL SLIDE SOUTHEAST ACROSS CENTRAL INDIANA ON SUNDAY
BRINGING A SMALL CHANCE OF RAIN OR SNOW IN BUT MORE IMPORTANTLY MUCH
COLDER TEMPERATURES. SMALL SNOW CHANCES WILL RETURN MIDWEEK AS
DISTURBANCES MOVE THROUGH IN FAST NORTHWEST FLOW ALOFT.
OTHERWISE...BELOW NORMAL TEMPERATURES WILL CONTINUE THROUGH ALL OF
NEXT WEEK.
&&
.NEAR TERM /TODAY/...
ISSUED AT 223 AM EST SAT DEC 28 2013
MAIN CHALLENGE TO THE NEAR TERM WILL BE TEMPERATURES AS MODELS AND
MOS HAVE BEEN UNDERESTIMATING THE LATEST WARMUP.
MODELS IN GOOD AGREEMENT THAT SURFACE HIGH PRESSURE ACROSS THE
TENNESSEE VALLEY WILL SLIDE EAST TO THE ATLANTIC OCEAN LATE TODAY
WITH SOUTHWEST LOW LEVEL FLOW CONTINUING ACROSS THE AREA. IN
ADDITION...UPPER LOW WILL MOVE NORTHEAST ACROSS NORTHERN TEXAS AND
POLAR FRONT WILL DROP SOUTHEAST ACROSS THE NORTHERN AND CENTRAL
PLAINS AHEAD OF A NORTHERN STREAM UPPER TROUGH. THE DAY SHOULD START
OFF SUNNY WITH MODEL TIME SECTIONS SHOWING A DRY COLUMN.
HOWEVER...HIGH CLOUDS WILL BE INCREASING FROM SOUTH TO NORTH AHEAD
OF THE SOUTHERN SYSTEM. HIGH RESOLUTION NAM12 AND RAP SOUNDINGS WERE
INDICATING INVERSION SHOULD BE IN PLACE AROUND 950 MILLIBARS...SO
WOULD NOT RULE OUT MIXING OF 3K FEET WINDS TO THE SURFACE WITH SOME
GUSTS TO NEAR 20 KNOTS. EITHER WAY...SHOULD SEE TEMPERATURES WARM TO
THE 50S TODAY...A FEW DEGREES WARMER THAN 00Z MOS.
&&
.SHORT TERM /TONIGHT THROUGH MONDAY NIGHT/...
ISSUED AT 223 AM EST SAT DEC 28 2013
MAIN FOCUS TO THE SHORT TERM WILL BE ON TEMPERATURES...ESPECIALLY
SUNDAY AS AN ARCTIC FRONT IS POISED TO DROP SOUTHEAST ACROSS CENTRAL
INDIANA. POPS AND PRECIPITATION TYPE WILL ALSO BE CHALLENGE ON
SUNDAY WITH THE FRONT MOVING THROUGH ALONG WITH A TRAILING UPPER
TROUGH. THE SOUTHERN TROUGH IS ALSO EXPECTED TO BRING RAIN CLOSE
TO...IF NOT ACROSS OUR FAR SOUTH OVERNIGHT SATURDAY NIGHT DEPENDING
ON MODEL OF CHOICE.
00Z GFS AND NAM CLOSE TO THE 12Z ECMWF REGARD HANDLING OF WEAKENING
SOUTHERN PLAINS UPPER LOW AND ALSO WITH THE ARCTIC FRONT.
HOWEVER...MODELS...ESPECIALLY THE GFS HAVE BEEN TRENDING FURTHER
NORTH WITH QPF WITH THE SOUTHERN SYSTEM SATURDAY NIGHT. A BLEND
WOULD WARRANT AT LEAST SMALL POPS AFTER 06Z SUNDAY FOR OUR SOUTHERN
TIER OR TWO. OTHERWISE...SHOULD SEE SKY COVER INCREASE FROM
SOUTH TO NORTH TONIGHT.
MODELS ON SUNDAY SUGGEST THE ARCTIC FRONT WILL BE ACROSS OUR
NORTHWEST COUNTIES SHORTLY AFTER 12Z AND AT OUR EASTERN BORDER
AROUND 18Z. SO...TRIED TO TIME HOURLY TEMPERATURES TO DROP FOLLOWING
THE FRONTAL PASSAGE AND THUS WARMEST TEMPERATURES WILL BE ACROSS THE
EASTERN COUNTIES AND COLDEST NORTHWEST PER 00Z ALLBLEND. WITH DEEPER
SOUTHERN SYSTEM MOISTURE PEELING OF TO THE NORTHEAST AND LITTLE
MOISTURE WITH ARCTIC SYSTEM...KEPT POPS LOW ON SUNDAY. REGARDING
PRECIPITATION TYPE...TRIED TO TIME THE MIX AND CHANGEOVER FROM SNOW
TO RAIN...FOLLOWING CLOSELY BUFKIT BLEND OF CANADIAN PARTIAL
THICKNESSES. THIS WOULD SUGGEST A MIX IN THE NORTHWEST SHORTLY
AFTER 12Z SUNDAY CHANGING TO ALL SNOW DURING THE AFTERNOON. THE
SOUTHEAST SHOULD START OFF AS RAIN AT 12Z AND MIX EARLY AFTERNOON
WITH ALL SNOW LATE AFTERNOON.
WITH THE SOUTHERN SYSTEM WELL NORTHEAST OF THE AREA AND THE NORTHERN
STREAM TROUGH MOISTURE STARVED...WILL NOT MENTION AND POPS SUNDAY
NIGHT.
MONDAY AND MONDAY NIGHT CONTINUE TO LOOK DRY WITH WEAK LOW PRESSURE
SYSTEM JUST TO OUR WEST MONDAY NIGHT MOISTURE STARVED.
00Z ALLBLEND LOOKS LIKE IT IS IN THE BALLPARK FOR TEMPERATURES FOR
THE MOST PART BY SUNDAY NIGHT WITH A FEW TWEAKS NEEDED HERE OR
THERE.
&&
.LONG TERM /TUESDAY THROUGH SATURDAY/...
ISSUED AT 230 AM EST SAT DEC 28 2013
MODELS CONTINUE TO ADVERTISE BROAD CYCLONIC FLOW ACROSS THE EASTERN
PORTION OF THE COUNTRY THROUGH THE LONG TERM PERIOD. ALTHOUGH THIS
MAY LEND ITSELF TO A WAVE OR TWO PROVIDING SOME LIGHT SNOW CHANCES
ACROSS THE AREA...TIMING THESE WAVES...ESPECIALLY THIS FAR OUT...IS
A LOSING PROPOSITION. THUS...FEEL IMPROVEMENTS ARE UNLIKELY TO BE
MADE OVER ALLBLEND INITIALIZATION ASIDE FROM MINOR TWEAKS. WILL
CARRY SLIGHT CHANCE OF SNOW SHOWERS TUESDAY NIGHT INTO WEDNESDAY
NIGHT WITH A POSSIBLE WAVE MOVING THROUGH THE FLOW.
DIFFERENCES ARE LESSENING BETWEEN THE GFS AND EURO...HOWEVER THERE
IS STILL SOME DISCREPANCY ESPECIALLY LATE IN THE PERIOD REGARDING
INTRUSION OF COLD AIR INTO THE LOWER 48 AND RESULTANT TEMPS.
AGAIN...FEEL IMPROVEMENT OVER MODEL BLEND ARE UNLIKELY AND WILL MAKE
FEW CHANGES HERE. WITH BROAD CYCLONIC FLOW...TEMPS SHOULD LARGELY BE
BELOW NORMAL UNTIL PERHAPS LATE IN THE PERIOD DEPENDING ON WHICH
SOLUTION VERIFIES.
&&
.AVIATION /DISCUSSION FOR THE 281500Z KIND TAF UPDATE/...
ISSUED AT 922 AM EST SAT DEC 28 2013
NO SIGNIFICANT CHANGES MADE TO THE FORECAST AT THIS TIME. PREVIOUS
DISCUSSION FOLLOWS.
VFR THOUGH THE PERIOD.
HIGH CLOUDS WILL CONTINUE ACROSS INDIANA THROUGH THE PERIOD...WITH A
GRADUAL LOWERING AND INCREASE OF MID AND HIGH CLOUDS IN THE LATTER
PORTION OF THE PERIOD.
NO VISIBILITY ISSUES EXPECTED THROUGH THE PERIOD. WINDS WILL BE 10KT
OR LESS THROUGHOUT...GENERALLY SOUTH THROUGH SOUTHWEST.
&&
.IND WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
SYNOPSIS...MK
NEAR TERM...MK
SHORT TERM...MK
LONG TERM...NIELD
AVIATION...NIELD/JAS
VISIT US AT HTTP://WWW.WEATHER.GOV/IND
FOLLOW US ON TWITTER AND YOUTUBE AT:
WWW.TWITTER.COM/NWSINDIANAPOLIS
WWW.YOUTUBE.COM/NWSINDIANAPOLIS
AREA FORECAST DISCUSSION
NWS INDIANAPOLIS IN
602 AM EST SAT DEC 28 2013
.UPDATE...
THE AVIATION SECTION HAS BEEN UPDATED BELOW.
&&
.SYNOPSIS...
ISSUED AT 223 AM EST SAT DEC 28 2013
SOUTHWEST WINDS ON THE BACK SIDE OF HIGH PRESSURE WILL ALLOW FOR
ABOVE NORMAL TEMPERATURES TODAY THROUGH MIDDAY SUNDAY. THEN...AN
ARCTIC FRONT WILL SLIDE SOUTHEAST ACROSS CENTRAL INDIANA ON SUNDAY
BRINGING A SMALL CHANCE OF RAIN OR SNOW IN BUT MORE IMPORTANTLY MUCH
COLDER TEMPERATURES. SMALL SNOW CHANCES WILL RETURN MIDWEEK AS
DISTURBANCES MOVE THROUGH IN FAST NORTHWEST FLOW ALOFT.
OTHERWISE...BELOW NORMAL TEMPERATURES WILL CONTINUE THROUGH ALL OF
NEXT WEEK.
&&
.NEAR TERM /TODAY/...
ISSUED AT 223 AM EST SAT DEC 28 2013
MAIN CHALLENGE TO THE NEAR TERM WILL BE TEMPERATURES AS MODELS AND
MOS HAVE BEEN UNDERESTIMATING THE LATEST WARMUP.
MODELS IN GOOD AGREEMENT THAT SURFACE HIGH PRESSURE ACROSS THE
TENNESSEE VALLEY WILL SLIDE EAST TO THE ATLANTIC OCEAN LATE TODAY
WITH SOUTHWEST LOW LEVEL FLOW CONTINUING ACROSS THE AREA. IN
ADDITION...UPPER LOW WILL MOVE NORTHEAST ACROSS NORTHERN TEXAS AND
POLAR FRONT WILL DROP SOUTHEAST ACROSS THE NORTHERN AND CENTRAL
PLAINS AHEAD OF A NORTHERN STREAM UPPER TROUGH. THE DAY SHOULD START
OFF SUNNY WITH MODEL TIME SECTIONS SHOWING A DRY COLUMN.
HOWEVER...HIGH CLOUDS WILL BE INCREASING FROM SOUTH TO NORTH AHEAD
OF THE SOUTHERN SYSTEM. HIGH RESOLUTION NAM12 AND RAP SOUNDINGS WERE
INDICATING INVERSION SHOULD BE IN PLACE AROUND 950 MILLIBARS...SO
WOULD NOT RULE OUT MIXING OF 3K FEET WINDS TO THE SURFACE WITH SOME
GUSTS TO NEAR 20 KNOTS. EITHER WAY...SHOULD SEE TEMPERATURES WARM TO
THE 50S TODAY...A FEW DEGREES WARMER THAN 00Z MOS.
&&
.SHORT TERM /TONIGHT THROUGH MONDAY NIGHT/...
ISSUED AT 223 AM EST SAT DEC 28 2013
MAIN FOCUS TO THE SHORT TERM WILL BE ON TEMPERATURES...ESPECIALLY
SUNDAY AS AN ARCTIC FRONT IS POISED TO DROP SOUTHEAST ACROSS CENTRAL
INDIANA. POPS AND PRECIPITATION TYPE WILL ALSO BE CHALLENGE ON
SUNDAY WITH THE FRONT MOVING THROUGH ALONG WITH A TRAILING UPPER
TROUGH. THE SOUTHERN TROUGH IS ALSO EXPECTED TO BRING RAIN CLOSE
TO...IF NOT ACROSS OUR FAR SOUTH OVERNIGHT SATURDAY NIGHT DEPENDING
ON MODEL OF CHOICE.
00Z GFS AND NAM CLOSE TO THE 12Z ECMWF REGARD HANDLING OF WEAKENING
SOUTHERN PLAINS UPPER LOW AND ALSO WITH THE ARCTIC FRONT.
HOWEVER...MODELS...ESPECIALLY THE GFS HAVE BEEN TRENDING FURTHER
NORTH WITH QPF WITH THE SOUTHERN SYSTEM SATURDAY NIGHT. A BLEND
WOULD WARRANT AT LEAST SMALL POPS AFTER 06Z SUNDAY FOR OUR SOUTHERN
TIER OR TWO. OTHERWISE...SHOULD SEE SKY COVER INCREASE FROM
SOUTH TO NORTH TONIGHT.
MODELS ON SUNDAY SUGGEST THE ARCTIC FRONT WILL BE ACROSS OUR
NORTHWEST COUNTIES SHORTLY AFTER 12Z AND AT OUR EASTERN BORDER
AROUND 18Z. SO...TRIED TO TIME HOURLY TEMPERATURES TO DROP FOLLOWING
THE FRONTAL PASSAGE AND THUS WARMEST TEMPERATURES WILL BE ACROSS THE
EASTERN COUNTIES AND COLDEST NORTHWEST PER 00Z ALLBLEND. WITH DEEPER
SOUTHERN SYSTEM MOISTURE PEELING OF TO THE NORTHEAST AND LITTLE
MOISTURE WITH ARCTIC SYSTEM...KEPT POPS LOW ON SUNDAY. REGARDING
PRECIPITATION TYPE...TRIED TO TIME THE MIX AND CHANGEOVER FROM SNOW
TO RAIN...FOLLOWING CLOSELY BUFKIT BLEND OF CANADIAN PARTIAL
THICKNESSES. THIS WOULD SUGGEST A MIX IN THE NORTHWEST SHORTLY
AFTER 12Z SUNDAY CHANGING TO ALL SNOW DURING THE AFTERNOON. THE
SOUTHEAST SHOULD START OFF AS RAIN AT 12Z AND MIX EARLY AFTERNOON
WITH ALL SNOW LATE AFTERNOON.
WITH THE SOUTHERN SYSTEM WELL NORTHEAST OF THE AREA AND THE NORTHERN
STREAM TROUGH MOISTURE STARVED...WILL NOT MENTION AND POPS SUNDAY
NIGHT.
MONDAY AND MONDAY NIGHT CONTINUE TO LOOK DRY WITH WEAK LOW PRESSURE
SYSTEM JUST TO OUR WEST MONDAY NIGHT MOISTURE STARVED.
00Z ALLBLEND LOOKS LIKE IT IS IN THE BALLPARK FOR TEMPERATURES FOR
THE MOST PART BY SUNDAY NIGHT WITH A FEW TWEAKS NEEDED HERE OR
THERE.
&&
.LONG TERM /TUESDAY THROUGH SATURDAY/...
ISSUED AT 230 AM EST SAT DEC 28 2013
MODELS CONTINUE TO ADVERTISE BROAD CYCLONIC FLOW ACROSS THE EASTERN
PORTION OF THE COUNTRY THROUGH THE LONG TERM PERIOD. ALTHOUGH THIS
MAY LEND ITSELF TO A WAVE OR TWO PROVIDING SOME LIGHT SNOW CHANCES
ACROSS THE AREA...TIMING THESE WAVES...ESPECIALLY THIS FAR OUT...IS
A LOSING PROPOSITION. THUS...FEEL IMPROVEMENTS ARE UNLIKELY TO BE
MADE OVER ALLBLEND INITIALIZATION ASIDE FROM MINOR TWEAKS. WILL
CARRY SLIGHT CHANCE OF SNOW SHOWERS TUESDAY NIGHT INTO WEDNESDAY
NIGHT WITH A POSSIBLE WAVE MOVING THROUGH THE FLOW.
DIFFERENCES ARE LESSENING BETWEEN THE GFS AND EURO...HOWEVER THERE
IS STILL SOME DISCREPANCY ESPECIALLY LATE IN THE PERIOD REGARDING
INTRUSION OF COLD AIR INTO THE LOWER 48 AND RESULTANT TEMPS.
AGAIN...FEEL IMPROVEMENT OVER MODEL BLEND ARE UNLIKELY AND WILL MAKE
FEW CHANGES HERE. WITH BROAD CYCLONIC FLOW...TEMPS SHOULD LARGELY BE
BELOW NORMAL UNTIL PERHAPS LATE IN THE PERIOD DEPENDING ON WHICH
SOLUTION VERIFIES.
&&
.AVIATION /DISCUSSION FOR THE 28/12Z TAFS/...
ISSUED AT 602 AM EST SAT DEC 28 2013
VFR THOUGH THE PERIOD.
HIGH CLOUDS WILL CONTINUE ACROSS INDIANA THROUGH THE PERIOD...WITH A
GRADUAL LOWERING AND INCREASE OF MID AND HIGH CLOUDS IN THE LATTER
PORTION OF THE PERIOD.
NO VISIBILITY ISSUES EXPECTED THROUGH THE PERIOD. WINDS WILL BE 10KT
OR LESS THROUGHOUT...GENERALLY SOUTH THROUGH SOUTHWEST.
&&
.IND WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
SYNOPSIS...MK
NEAR TERM...MK
SHORT TERM...MK
LONG TERM...NIELD
AVIATION...NIELD
VISIT US AT HTTP://WWW.WEATHER.GOV/IND
FOLLOW US ON TWITTER AND YOUTUBE AT:
WWW.TWITTER.COM/NWSINDIANAPOLIS
WWW.YOUTUBE.COM/NWSINDIANAPOLIS
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
1128 AM CST SAT DEC 28 2013
.DISCUSSION...
339 AM CST
THE ROLLER COASTER RIDE IN TEMPERATURES THIS FINAL WEEKEND OF 2013 IS
THE PRIMARY FORECAST CHALLENGE...WITH A STRIKING 50 DEGREE
DIFFERENCE FROM HIGHS THIS AFTERNOON TO MORNING TEMPERATURES ON
MONDAY EXPECTED. THE UPCOMING SHARP DIP ON OUR RIDE WILL TAKE US
INTO THE FIRST DAYS OF THE NEW YEAR WITH ANOMALOUS COLD SET FOR
NEXT WEEK. TEMPERATURES AND SNOW POTENTIAL IN THAT PATTERN WERE
THE NEXT CHALLENGES WITH THIS FORECAST.
TODAY...SOUTHWEST FLOW CONTINUES OVER THE AREA THIS MORNING WITH
TEMPERATURES AT OR ABOVE FREEZING AT 330 AM ACROSS MOST CWA
COMMUNITIES. THIS MILD STARTING POINT OFFERS A NICE SPRINGBOARD FOR
TEMPERATURES ALREADY SET TO BE THE WARMEST SINCE DECEMBER 4TH. AS
LOW PRESSURE FROM ND EARLY THIS MORNING MOVES TO WESTERN WI BY EARLY
EVE...A WARM SECTOR WITH SOUTHWEST FLOW WILL BE IN PLACE ACROSS THE
AREA. LITTLE IN THE WAY OF CLOUDS IS SEEN ON MORNING SATELLITE AND
UPPER LEVEL SUPPRESSION IS EVEN INDICATED ON WATER VAPOR WHICH LOOKS
TO REMAIN THROUGH MIDDAY FURTHER ALLOWING FOR A SUN-FILLED SKY. THE
SNOW PACK PROVIDED A 10 TO AS MUCH AS 15 DEGREE TEMPERATURE GRADIENT
ACROSS THE FORECAST AREA YESTERDAY AND WOULD EXPECT NEAR THAT TODAY.
HAVE GUIDED BY YESTERDAYS LAST VISIBLE IMAGERY AS WELL AS NOHRSC
DATA FOR SNOW COVER INFLUENCE. THE 00Z/06Z NAM LOOKS ABOUT 1-1.5C
WARM ON 925MB TEMPS BASED ON LAST EVES SOUNDINGS...SO HAVE GONE
CLOSER TO THE 8-9C PROJECTED OVER THE AREA BY MOST OTHER GUIDANCE.
CLIMATOLOGY SUGGESTS LOW-MID 50S WITH THIS AS AN AVERAGE...AND EVEN
LOCAL ON-THE-FLY RESEARCH DONE EARLIER IN THE WEEK BY A COLLEAGUE
INDICATED 54 AS AN AVERAGE AT ORD WITH THESE 925MB TEMPS AND SW FLOW.
IT LOOKS LIKE AREAS JUST EAST OF THE SNOW PACK...INCLUDING
CHICAGO...WILL STILL HAVE SOME MODIFICATION OF THE SW FLOW BASED ON
PARCEL TRAJECTORIES OVER SNOW PACK SO HAVE UNDERCUT THAT 54 BY A
HANDFUL OF DEGREES...BUT DO EXPECT THE 50 DEGREE ISOTHERM TO BISECT
THE METRO AREA WITH THE SOUTH SIDE WARMING THE MOST. EVEN THE 13KM
RAP FORECAST TEMPS THROUGH THIS AFTERNOON INDICATE THIS TYPE OF
TREND. AREAS SOUTH OF INTERSTATE 80 AND EAST OF ILLINOIS 47 SHOULD
BE ABLE TO REALIZE THOSE MID 50S.
TONIGHT INTO SUNDAY...HAVE GUIDED WITH THE SLIGHTLY FASTER NAM
TIMING ON THE COLD FRONTAL PASSAGE...BUT ALL IN ALL GUIDANCE/MOS IS
BASICALLY WITHIN 3 HRS OF FROPA FOR ANY ONE POINT. THE UPPER WAVE OF
THIS SYSTEM IS WELL-DEFINED ON WATER VAPOR OVER MT EARLY THIS
MORNING AND ALREADY 160M HEIGHT FALLS WERE OBSERVED AT 500MB WITH
IT LAST NIGHT. THE FRONT IS DRIVEN BY THE COLLECTIVE STRONG COLD
AIR ADVECTION...THICKNESS FALLS...AND SURFACE PRESSURE RISES AND
SHOULD HAVE GOOD MOMENTUM TO DRIVE IT. THE MERCURY WILL DROP
THROUGH THE DAY SUNDAY WITH WIND CHILLS LIKELY TO FALL BELOW ZERO
ACROSS NORTH CENTRAL IL DURING THE AFTERNOON. OVERCAST STRATOCU IS
EXPECTED IMMEDIATELY IN THE WAKE OF FROPA AS INDICATED BY FORECAST
MODEL SOUNDINGS. THE DEPTH OF THE SATURATED LAYER WITH RESPECT TO
ICE IS FAIRLY SHALLOW AT THE TOP OF THE MIXED LAYER...AND OMEGA IS
NOT FORECAST TO BE THE BEST FOR WIDESPREAD SNOW SHOWERS.
HOWEVER...UPPER LEVEL FORCING ALONG THE 650-850MB BAROCLINIC ZONE
BEHIND THE FRONT MAY ALSO HELP FOR SOME LIGHT SNOW MORE SO INTO
THE AFTERNOON. GIVEN THE DEGREE OF COLD AIR ADVECTION...THIS
CONTINUES TO LOOK LIKE A POST-FRONTAL AIR MASS THAT WOULD HAVE SOME
LIGHT SNOW/SNOW SHOWERS...WITH BEST CHANCES IN THE NORTHERN
FORECAST AREA. SO HAVE CONTINUED THAT IN THE FORECAST ON SUNDAY
AND EARLY SUNDAY EVE. LAKE EFFECT TRAJECTORIES CONTINUE TO FAVOR
JUST EAST OF OUR NW INDIANA COUNTIES FOR ANY SHOWERS DURING
SUNDAY NIGHT. TEMPERATURES SUNDAY NIGHT ARE STILL FORECAST TO HEAD
BELOW ZERO ACROSS A LARGE PART OF THE IL FORECAST AREA.
WIND CHILL HEADLINE POTENTIAL...SUSTAINED WIND SPEEDS AROUND 15
MPH TO START SUNDAY EVE WILL ONLY VERY GRADUALLY DIMINISH DURING
SUNDAY NIGHT. WHILE DEFINITE ADVISORY CRITERIA WILL BE MET...AT
THIS POINT WARNING CRITERIA IS NOT FORECAST ALTHOUGH IT MAY BE
CLOSE IN NORTH CENTRAL IL SUNDAY NIGHT INTO EARLY MONDAY. SO HAVE
NOT OPTED ANY WATCH AT THIS TIME. IN ADDITION...WIND CHILL
ADVISORY CRITERIA MAY BE CLOSE AGAIN TUESDAY NIGHT INTO EARLY
WEDNESDAY.
NEXT WEEK...A NORTHWEST JET AROUND 150KT WILL RE-INTENSIFY THE
HUDSON BAY TROUGH WITH 500MB HEIGHTS AT ITS CENTER FORECAST TO DIP
TO AN EYE-OPENING LOW 481DM. THIS WILL ALLOW FOR ESTABLISHED
NORTHWEST FLOW OVER THE MIDWEST AND WITH THAT ONCE AGAIN COMES
SEVERAL SMALL MID-LEVEL PERTURBATIONS CAPABLE OF SNOW. AS THIS
PAST WEEK SHOWED...THESE ARE CHALLENGING TO FORECAST SPECIFICS
WELL IN ADVANCE. OVERALL...THE PATTERN WILL BE FAVORABLE FOR THESE
TO BRING MINOR ACCUMULATIONS OVER THE PATH THEY TAKE...JUST GIVEN
A DEEPER DENDRITIC GROWTH ZONE ABLE TO BE SATURATED WITH EACH
IMPULSE. MONDAY NIGHT AND AGAIN TUESDAY NIGHT AT THIS TIME ARE THE
AVERAGES IN GUIDANCE FOR POTENTIALLY LIGHT ACCUMULATING
SNOW...BUT AGAIN QUITE A BIT COULD CHANGE WITH THESE. FOR
TEMPERATURES...EACH IMPULSE LOOKS TO KEEP THE COLD AIR IN PLACE
WITH ONLY VERY MINIMAL WARM AIR ADVECTION IN ADVANCE OF ANY OF
THESE. HAVE UNDERCUT A MODEL MEAN SLIGHTLY OVER THE NORTHWEST
FORECAST AREA WHERE SNOW PACK STILL SHOULD HAVE GREATER INFLUENCE
TO KEEP TEMPS DOWN. ALL IN ALL THOUGH VERY LITTLE CHANGES TO
PREVIOUS FORECAST FOR NEXT WEEK.
MTF
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 18Z...
* SOUTH-SOUTHWEST WINDS GUSTING NEAR 20 KT THIS AFTERNOON.
* COLD FRONTAL PASSAGE EARLY SUNDAY MORNING.
* GUSTY NORTHWEST WINDS AROUND 25 KT SUNDAY.
* MVFR CIGS LIKELY WITH LGT SNOW/SNOW SHOWERS PRODUCING MVFR/IFR VSBYS.
RATZER
//DISCUSSION...UPDATED 18Z...
RELATIVELY QUIET AVIATION WEATHER ACROSS THE FORECAST AREA THIS
AFTERNOON. LOW PRESSURE JUST NORTH OF KFSD WILL CONTINUE TO MOVE
EAST ACROSS MINNESOTA AND WISCONSIN THROUGH THIS EVENING...WITH
SURFACE PRESSURE FALLS AND RELATIVELY TIGHT PRESSURE GRADIENT
INDUCING WINDS FROM 210-230 DEGREES GUSTING TO NEAR 20 KT THIS
AFTERNOON. FORECAST SOUNDINGS DEPICT RATHER SHALLOW MIXED LAYER
WITH WARM AIR ALOFT...WHICH SUGGESTS GUSTS WILL DECREASE EARLY
THIS EVENING WHILE SUSTAINED SPEEDS HOLD IN THE 10-15 KT RANGE
UNTIL GRADIENT BEGINS TO WEAKEN IN ADVANCE OF COLD FRONTAL TROUGH
LATER TONIGHT. LATEST MODEL RUNS MAINTAIN FRONTAL PASSAGE IN THE
10-12Z RANGE EARLY SUNDAY MORNING...WITH A WIND SHIFT INITIALLY TO
THE WEST...AND THEN SHIFTING NORTHWEST AND INCREASING IN SPEED WITHIN
A FEW HOURS. DEEPENING MIXED LAYER WITH STRONG COLD ADVECTION WILL
AID IN MIXING STRONGER GUSTS AROUND 25 KT BUT OCCASIONALLY A
LITTLE HIGHER TO THE SURFACE BY MID- MORNING AND CONTINUING
THROUGH THE REST OF THE DAY.
STRONG COLD ADVECTION WILL HELP MOISTEN THE COLUMN AS MID-LEVEL
TROUGH APPROACHES...RESULTING IN MVFR STRATOCU DEVELOPMENT BEHIND
THE FRONT. FORECAST SOUNDINGS INDICATE CLOUD BASES AROUND 1500 FT
AGL...WITH LIGHT SNOW/SNOW SHOWERS BECOMING LIKELY AS THE COLUMN
MOISTENS AND COOLS DURING THE LATER MORNING/AFTERNOON HOURS.
DEEPER MOISTURE AND LIFT ACROSS THE AREA DURING THE AFTERNOON
SHOULD SUPPORT AT LEAST OCCASIONAL VISIBILITY REDUCTION THROUGH
MVFR/IFR RANGE...ESPECIALLY AS LOW LEVELS COOL INTO BETTER CRYSTAL
PRODUCTION TEMPERATURES.
RATZER
//ORD AND MDW CONFIDENCE...UPDATED 18Z...
* HIGH CONFIDENCE IN WIND TRENDS AND VFR CONDITIONS PREVAILING
UNTIL EARLY SUNDAY MORNING.
* MEDIUM-HIGH CONFIDENCE IN MVFR CIGS AROUND 1500 FT DEVELOPING
BEHIND COLD FRONT SUNDAY.
* MEDIUM CONFIDENCE IN -SN/SHSN TIMING AND VSBY.
RATZER
//OUTLOOK FOR ORD/MDW FOR 00Z MONDAY-12Z SATURDAY...UPDATED 12Z...
SUNDAY NIGHT...MVFR CIGS...BECOMING VFR OVERNIGHT.
MONDAY...VFR...BECOMING MVFR MON NIGHT WITH A CHANCE OF SNOW.
TUESDAY...MVFR CIGS. CHANCE OF LIGHT SNOW.
WEDNESDAY...MVFR CIGS. CHANCE OF LIGHT SNOW.
THURSDAY...VFR.
FRIDAY...VFR. SLIGHT CHANCE OF SNOW SHOWERS.
TRS
&&
.MARINE...
441 AM CST
A STRONG SW FLOW WILL DEVELOP TODAY AS LOW PRESSURE MOVES SE FROM
ND TO WI. HOWEVER...WITH STRONG WARM AIR ADVECTION CONTINUING AND
THE WATER IN THE LOWER TO MID 30S F THE SURFACE WILL BE DECOUPLED
FROM THE STRONG FLOW JUST ABOVE THE BASE OF THE TEMPERATURE
INVERSION. NORTHWEST GALES OF 35 TO 40 KT WILL ARRIVE DURING THE
PREDAWN HOURS OF SUNDAY ON THE N END OF LAKE MICHIGAN...AND THE
S END BY MID MORNING SUNDAY AS THE LOW MOVES E ACROSS FAR N LAKE
MI INTO NORTHERN LOWER MI OVERNIGHT AND THE TRAILING COLD FRONT
SWEEPS SE ACROSS THE LAKE OVERNIGHT TONIGHT AND EARLY SUN MORNING.
ARCTIC AIR WILL OVERSPREAD THE UPPER GREAT LAKES BEHIND THE COLD
FRONT RESULTING IN A VERY UNSTABLE CONDITION DUE TO THE LARGE
CONTRAST BETWEEN WATER AND AIR TEMPERATURE. THIS WILL RESULT IN
EFFICIENT TRANSFER OF STRONG WINDS RIGHT DOWN TO THE LAKE
SURFACE. IN ADDITION...STRONG HIGH PRESSURE WILL BE BUILDING SE
FROM S SASKATCHEWAN ACROSS THE N AND CENTRAL PLAINS OVERNIGHT
TONIGHT AND SUN. WINDS WILL GRADUALLY DIMINISH SUN NIGHT AS THIS
HIGH MOVES TO THE UPPER AND MID MS VALLEY.
A GALE WARNING IS UP FOR ALL THE OPEN WATERS OF THE LAKE...STARTING
IN THE PREDAWN HOURS ON THE N...AND MID MORNING ON THE S. A GALE
WARNING IS ALSO IN EFFECT FOR THE NEARSHORE FROM GARY TO MI CITY .
A SMALL CRAFT ADVISORY WILL LIKELY BE NEEDED FROM WINTHROP HARBOR
TO GARY DURING SUN AND SUN NIGHT.
TRS
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...GALE WARNING...LMZ261-LMZ362-LMZ364-LMZ366-LMZ563-LMZ565...4 AM
SUNDAY TO 6 PM SUNDAY.
GALE WARNING...LMZ080-LMZ567-LMZ669-LMZ671-LMZ673-LMZ675-LMZ744-
LMZ745-LMZ777-LMZ779-LMZ868-LMZ870-LMZ872-LMZ874-LMZ876-
LMZ878...9 AM SUNDAY TO 9 PM SUNDAY.
&&
$$
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WWW.TWITTER.COM/NWSCHICAGO
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Area Forecast Discussion
National Weather Service Lincoln IL
1111 AM CST Sat Dec 28 2013
.DISCUSSION...
ISSUED 936 AM CST Sat Dec 28 2013
Temperature trends remain the primary forecast concern for today.
Already have widespread upper 30s and lower 40s over the CWA, even
in the snow covered northwest. Most of the model guidance
continues to run too cool. Have favored the HRRR which looks good
in most areas, except it also is too cool where the snow is
currently in place. Morning cooperative weather observations, as
well as visible satellite imagery, show 1-2 inches still on the
ground early this morning across Knox, Stark and western
Marshall Counties. Should still get in the upper 40s there, but
50-55 will be common elsewhere this afternoon. Have sent updated
grids to reflect the latest trends, but the worded forecasts still
look good.
Geelhart
&&
.AVIATION...
ISSUED 1110 AM CST Sat Dec 28 2013
Main concern remains in the latter part of the TAF period, as a
cold front passes through. Through 06Z, will gradually see high
clouds move in and slowly lower. The front itself will be sweeping
across the central Illinois TAF sites between 10-14Z. Ceilings
expected to fall below 2000 feet with the passage of the front,
remaining there the rest of the TAF period. Northwest winds
expected to gust to around 20 knots behind the front as Arctic air
rushes into the area.
Geelhart
&&
.PREV DISCUSSION...
ISSUED 330 AM CST Sat Dec 28 2013
SHORT TERM...Today through Monday
00Z short range models are in good agreement through Monday and
will use a blend. Polar vortex over northeast Canada through mid
week to have northern stream short waves passing through the
Midwest and Great Lakes region around Monday night into Tue night
and another one around Thu. Models differ with timing and
placement of these features and will use a blend of models and
previous forecast for this package.
Another mild day today expected across central and southeast IL
with some areas getting in the low to mid 50s. Then an arctic cold
front near the US/Canadian border to pass SE through IL later
tonight into Sunday morning. Just a small chance of light
precipitation Sunday (mainly light snow or flurries). More
importantly, this front to usher in another arctic air mass Sunday
and Sunday night and will stick around through Thursday night.
Early morning surface map shows 1030 mb high pressure over the
southeast states while 1004 mb low pressure along the MT/ND and
Canadian border. SW winds over IL keeping milder temps in the mid
to upper 30s early this morning with nearly clear skies. 568 dm
500 mb low over west Texas has high/cirrus clouds spreading
northward into the mid MS valley including far southern IL and KY
early this morning. Some of these thin high clouds to spread into
central and especially southeast IL today with a fair amount of
sunshine still expected today. SW winds 10-15 mph and gusts 15-20
mph to boost highs in the low to mid 50s this afternoon, expected
upper 40s NW of the IL river where a light snow cover remains
especially over Knox and Stark counties.
Arctic cold front near the US/Canadian border to push SE through
the IL river valley late tonight and have temps dropping into the
upper teens and lower 20s NW of the IL river by dawn while milder
low to mid 30s over eastern/SE IL for lows tonight. Clouds to
increase during tonight with a fair amount of clouds Sunday as
arctic front pass SE through eastern/SE IL Sunday morning. Not
much moisture to work with so think mainly small chance of very
light precipitation Sunday behind the front in from of light snow
or flurries, though light rain possible Sunday morning over SE IL.
Highs Sunday in the morning range from the lower 20s NW of the IL
river to the upper 30s and lower 40s in southeast IL with falling
temps through the day behind the arctic front.
Very cold air advects into IL Sunday night into Monday with wind
chills likely getting to 15 to 20 below zero north of I-72
overnight Sunday night into Monday morning and will likely need a
wind chill advisory as event gets closer. Lows Sunday night to be
in the single digits below from I-55 NW with highs Monday from 8-14
north of I-72.
LONG TERM...Monday night through Friday
Very cold conditions expected to continue Monday night through Thu
night with polar vortex in northeast Canada and strong upper level
trof over the region and reinforced on Thursday. A northern stream
short wave approaches northern counties during Monday night with
slight chance of light snow or flurries and gets further into
central IL Tue and Tuesday night before exiting on Wed. Not
expecting much accumulations of snow at this point in dry air mass.
Could be another chance of flurries on Thursday with strong upper
level trof and possible short wave moving thru region. Large upper
level trof shifts east of IL Fri/Sat with temps moderating closer
to normal with dry conditions expected.
07
&&
.ILX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS GOODLAND KS
200 PM MST SAT DEC 28 2013
.SHORT TERM...(THIS EVENING THROUGH SUNDAY)
ISSUED AT 117 PM MST SAT DEC 28 2013
THE LAST WEEKEND OF 2013 KICKED OFF YESTERDAY WITH WELL ABOVE-NORMAL
TEMPERATURES AND WILL END WITH A VERY COLD SUNDAY. AN ARCTIC COLD
FRONT ON THE WAY TODAY WILL BRING THE COLD AIR AS WELL AS STRONG
WINDS. A FEW FLURRIES ARE POSSIBLE TONIGHT INTO EARLY SUNDAY...BUT
THE MAIN IMPACT OF THIS FRONT WILL BE THE WIND AND COLD. ON SUNDAY
SKIES WILL BECOME MOSTLY SUNNY BUT TEMPERATURES WILL HAVE A TOUGH
TIME GETTING ABOVE FREEZING.
TODAY...SATURDAY...SUNNY AND MILD TO START...BECOMING WINDY AND
COLD. FRONTAL PASSAGE LOOKS TO OCCUR IN THE EARLY AFTERNOON...WITH A
REINFORCING SHOT OF COLD AIR TONIGHT. AHEAD OF THE FRONT IT WILL BE
A NICE DAY SIMILAR TO YESTERDAY WITH SUNNY SKIES...MILD TEMPS...AND
A LIGHT WEST/SOUTHWESTERLY WIND. HIGHS MIGHT EVEN APPROACH RECORD
VALUES TODAY WHICH ARE IN THE MID TO UPPER 60S FOR MOST STATIONS. /RECORD
HIGH OF 67 AT HILL CITY LOOKS TO HAVE THE BEST CHANCE OF BEING
BROKEN OUT OF THE FOUR ASOS SITES./ THE INITIAL FRONT WILL RACE
SOUTH ACROSS THE REGION EARLY THIS AFTERNOON...BRINGING GUSTY WINDS.
DECIDED TO REMOVE THE BLOWING DUST FROM THE WX GRID AS EXPECT ANY
BLOWING DUST/DIRT TO BE VERY LIMITED SPATIALLY/TEMPORALLY BASED ON
THE LATEST SHORT-TERM GUIDANCE. MID/HIGH LEVEL CLOUD COVER
ASSOCIATED WITH THE FRONT WILL ARRIVE LATER THIS AFTERNOON...WITH
LOW-LEVEL STRATUS CLOUDS THIS EVENING.
TONIGHT...STRONG PRESSURE RISES SUPPORT WINDY CONDITIONS THROUGH THE
NIGHT WITH LIGHT SNOW POSSIBLE IN EASTERN COLORADO. OVERCAST SKIES
WITH A LOW STRATUS DECK IN THE EVENING AND MID-LEVEL CLOUDS
PERSISTING THROUGH MOST OF THE NIGHT. WINDS WILL CONTINUE AS STRONG
PRESSURE RISES /5-8 MB/HR/ ARE EXPECTED AND MIXING OCCURS. A FEW
FLURRIES/LIGHT SNOW POSSIBLE IN EASTERN COLORADO AND PORTIONS OF NW
KANSAS WITH THE COMBINATION OF LOW LEVEL MOISTURE AND
FRONTOGENETICAL FORCING IN PLACE. GUIDANCE HAS BEEN QUITE CONSISTENT
RUN-TO-RUN...AND EARLY NCEP RAP AND ESRL RAP RUNS SUPPORT AT LEAST
SOME FLURRIES FOR MOST SPOTS. ACCUMULATIONS ARE NOT EXPECTED TO
AMOUNT TO MUCH...BUT WOULD NOT BE SURPRISED IF WESTERN PARTS OF
CHEYENNE/KIT CARSON COUNTIES IN COLORADO RECEIVE A HALF INCH.
/THOUGH IT WILL BE HARD TO MEASURE WITH ALL THE WIND.../ LOWS WILL
REACH THE SINGLE DIGITS IN MANY LOCATIONS WITH 850MB TEMPS IN THE
-12 TO -15 C RANGE AND STRONG COLD AIR ADVECTION.
TOMORROW...SUNDAY...COLD AND MOSTLY SUNNY. AT DAWN SUNDAY CLOUDS
WILL BE CLEARING FROM NORTHWEST TO SOUTHEAST...BECOMING MOSTLY SUNNY
EVERYWHERE BY THE AFTERNOON. WINDS WILL BE LIGHT OUT OF THE
NORTH/NORTHWEST AT 10 TO 15 MPH. DESPITE THE SUN HIGHS WILL STRUGGLE
TO REACH ABOVE FREEZING AS HIGH PRESSURE STRENGTHENS ACROSS THE
NORTHERN PLAINS.
.LONG TERM...(SUNDAY NIGHT THROUGH SATURDAY)
ISSUED AT 200 PM MST SAT DEC 28 2013
SUNDAY NIGHT-TUESDAY...PERIODIC INCREASES IN MID AND HIGH CLOUDS
EXPECTED UNDER NORTHWEST FLOW ALOFT. NO PRECIPITATION EXPECTED. MAY
SEE SOME BREEZY NORTHWEST WINDS MONDAY AFTERNOON.
LOWS SUNDAY NIGHT AROUND 10 ACROSS THE EAST AND WESTERN PORTIONS OF
CHEYENNE COUNTY COLORADO...LOW TO MID TEENS ELSEWHERE. HIGHS MONDAY
MID 40S TO AROUND 50. MAY HAVE A BIT OF SNOW COVER TO DEAL WITH
ACROSS THE WEST AND HAVE MID 40S IN THAT AREA. ON TUESDAY 850
TEMPERATURES WARM ABOUT 13-15F ACROSS THE AREA SUPPORTING HIGHS IN
THE MID 50S (NORTHEAST) TO MID 60S (WEST). BIAS CORRECTED GRIDS
ALONG THE 2M/MET/MAV ARE SEVERAL DEGREES COOLER. HAVE GENERALLY
BLENDED ALL SOLUTIONS TRYING TO TREND A BIT CLOSER TO 850
TEMPERATURES. HAVE SETTLED ON LOW TO MID 50S FAR NORTHEAST-EAST WITH
UPREAR 50S TO AROUND 60 ACROSS THE WESTERN/SOUTHWESTERN 2/3 OF THE
AREA.
TUESDAY NIGHT-SATURDAY...THERE IS A SLIGHT CHANCE OF LIGHT
PRECIPITATION WEDNESDAY AS A LARGE AREA OF MOISTURE MOVES IN FROM
THE NORTHWEST...AIDED BY APPROACHING LEFT FRONT PORTION OF UPPER
JET. BETTER CHANCES OF PRECIP GENERALLY ACROSS NORTHEAST 1/2 OF THE
FORECAST AREA. THIS SYSTEM EXITS THE AREA EARLY WEDNESDAY NIGHT.
OTHERWISE...A DRY FORECAST EXPECTED. LOWS THROUGH THURSDAY NIGHT IN
THE TEENS TO LOW 20S WITH MID 20S FRIDAY NIGHT. HIGHS WEDNESDAY IN
THE LOW 30S EAST TO LOW/MID 40S FAR WEST...SLOWLY WARMING INTO THE
LOW TO MID 40S (EAST TO WEST) THURSDAY. ON FRIDAY WE SHOULD RETURN
TO ABOVE NORMAL TEMPERATURES WITH UPPER 40S TO MID 50S. A RETURN TO
NEAR NORMAL HIGHS SATURDAY WITH LOW TO MID 40S.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SUNDAY AFTERNOON)
ISSUED AT 1044 AM MST SAT DEC 28 2013
VFR TO MVFR CONDITIONS EXPECTED AT GLD AND MCK THROUGH THE TAF
PERIOD. VFR CONDITIONS THIS MORNING WILL HOLD THROUGH THE EARLY
AFTERNOON. COLD FRONT DROPPING SOUTH ACROSS THE HIGH PLAINS WILL
BRING A WIND SHIFT AND DRAMATIC INCREASE IN WINDS...WITH GUSTS OVER
30KTS AROUND 21-23Z. WHILE GUSTS COULD CAUSE SOME BLOWING
DUST...BELIEVE ANY VISIBILITY-OBSTRUCTING BLOWING DUST WILL BE
BRIEF. WINDS WILL CONTINUE THROUGH THE NIGHT...GRADUALLY DECREASING
TOWARDS DAWN. EARLY THIS EVENING STRATUS WILL MOVE IN RESULTING IN
MVFR CEILINGS BECOMING VFR. A FEW FLURRIES ARE ALSO POSSIBLE THIS
EVENING AT GLD...BUT CHANCES ARE LOW SO DID NOT INCLUDE A MENTION IN
THIS ISSUANCE.
&&
.GLD WATCHES/WARNINGS/ADVISORIES...
KS...NONE.
CO...NONE.
NE...NONE.
&&
$$
SHORT TERM...JJM
LONG TERM...99
AVIATION...JJM
AREA FORECAST DISCUSSION
NWS GOODLAND KS
118 PM MST SAT DEC 28 2013
.SHORT TERM...(THIS EVENING THROUGH SUNDAY)
ISSUED AT 117 PM MST SAT DEC 28 2013
THE LAST WEEKEND OF 2013 KICKED OFF YESTERDAY WITH WELL ABOVE-NORMAL
TEMPERATURES AND WILL END WITH A VERY COLD SUNDAY. AN ARCTIC COLD
FRONT ON THE WAY TODAY WILL BRING THE COLD AIR AS WELL AS STRONG
WINDS. A FEW FLURRIES ARE POSSIBLE TONIGHT INTO EARLY SUNDAY...BUT
THE MAIN IMPACT OF THIS FRONT WILL BE THE WIND AND COLD. ON SUNDAY
SKIES WILL BECOME MOSTLY SUNNY BUT TEMPERATURES WILL HAVE A TOUGH
TIME GETTING ABOVE FREEZING.
TODAY...SATURDAY...SUNNY AND MILD TO START...BECOMING WINDY AND
COLD. FRONTAL PASSAGE LOOKS TO OCCUR IN THE EARLY AFTERNOON...WITH A
REINFORCING SHOT OF COLD AIR TONIGHT. AHEAD OF THE FRONT IT WILL BE
A NICE DAY SIMILAR TO YESTERDAY WITH SUNNY SKIES...MILD TEMPS...AND
A LIGHT WEST/SOUTHWESTERLY WIND. HIGHS MIGHT EVEN APPROACH RECORD
VALUES TODAY WHICH ARE IN THE MID TO UPPER 60S FOR MOST STATIONS. /RECORD
HIGH OF 67 AT HILL CITY LOOKS TO HAVE THE BEST CHANCE OF BEING
BROKEN OUT OF THE FOUR ASOS SITES./ THE INITIAL FRONT WILL RACE
SOUTH ACROSS THE REGION EARLY THIS AFTERNOON...BRINGING GUSTY WINDS.
DECIDED TO REMOVE THE BLOWING DUST FROM THE WX GRID AS EXPECT ANY
BLOWING DUST/DIRT TO BE VERY LIMITED SPATIALLY/TEMPORALLY BASED ON
THE LATEST SHORT-TERM GUIDANCE. MID/HIGH LEVEL CLOUD COVER
ASSOCIATED WITH THE FRONT WILL ARRIVE LATER THIS AFTERNOON...WITH
LOW-LEVEL STRATUS CLOUDS THIS EVENING.
TONIGHT...STRONG PRESSURE RISES SUPPORT WINDY CONDITIONS THROUGH THE
NIGHT WITH LIGHT SNOW POSSIBLE IN EASTERN COLORADO. OVERCAST SKIES
WITH A LOW STRATUS DECK IN THE EVENING AND MID-LEVEL CLOUDS
PERSISTING THROUGH MOST OF THE NIGHT. WINDS WILL CONTINUE AS STRONG
PRESSURE RISES /5-8 MB/HR/ ARE EXPECTED AND MIXING OCCURS. A FEW
FLURRIES/LIGHT SNOW POSSIBLE IN EASTERN COLORADO AND PORTIONS OF NW
KANSAS WITH THE COMBINATION OF LOW LEVEL MOISTURE AND
FRONTOGENETICAL FORCING IN PLACE. GUIDANCE HAS BEEN QUITE CONSISTENT
RUN-TO-RUN...AND EARLY NCEP RAP AND ESRL RAP RUNS SUPPORT AT LEAST
SOME FLURRIES FOR MOST SPOTS. ACCUMULATIONS ARE NOT EXPECTED TO
AMOUNT TO MUCH...BUT WOULD NOT BE SURPRISED IF WESTERN PARTS OF
CHEYENNE/KIT CARSON COUNTIES IN COLORADO RECEIVE A HALF INCH.
/THOUGH IT WILL BE HARD TO MEASURE WITH ALL THE WIND.../ LOWS WILL
REACH THE SINGLE DIGITS IN MANY LOCATIONS WITH 850MB TEMPS IN THE
-12 TO -15 C RANGE AND STRONG COLD AIR ADVECTION.
TOMORROW...SUNDAY...COLD AND MOSTLY SUNNY. AT DAWN SUNDAY CLOUDS
WILL BE CLEARING FROM NORTHWEST TO SOUTHEAST...BECOMING MOSTLY SUNNY
EVERYWHERE BY THE AFTERNOON. WINDS WILL BE LIGHT OUT OF THE
NORTH/NORTHWEST AT 10 TO 15 MPH. DESPITE THE SUN HIGHS WILL STRUGGLE
TO REACH ABOVE FREEZING AS HIGH PRESSURE STRENGTHENS ACROSS THE
NORTHERN PLAINS.
.LONG TERM...(SUNDAY THROUGH FRIDAY)
ISSUED AT 202 AM MST SAT DEC 28 2013
SUNDAY NORTH WINDS WILL CONTINUE TO DECLINE AS THE FRONT MOVES
FURTHER SOUTH. AS THE SURFACE HIGH PRESSURE MOVES ACROSS THE AREA A
WEAK WARM FROM WILL DEVELOP BEHIND IT NEAR THE KS/CO BORDER WITH LOW
30S TO THE WEST AND UPPER 20S TO THE EAST. WITH A DRY ENVIRONMENT
OVERHEAD DO NOT EXPECT PRECIP. TO DEVELOP DESPITE THE LEFT EXIT OF
THE 300MB JET MOVING OVER THE AREA.
SUNDAY NIGHT THE LEFT EXIT OF THE 300MB JET WILL LINGER OVER THE
AREA. HOWEVER THE DRY ENVIRONMENT WILL PERSIST SO WILL KEEP THE
FORECAST DRY.
MONDAY THE MID AND UPPER LEVELS MOISTEN BUT LARGE SCALE SUBSIDENCE
WILL MOVE OVER THE AREA NEGATING ANY CHANCE FOR PRECIP. DESPITE THE
MOISTURE TO WORK WITH. DURING THE MORNING A SURFACE TROUGH WILL MOVE
THROUGH THE AREA PUSHING THE WARM FRONT EAST OF THE AREA BY EARLY
AFTERNOON. BEHIND THE FRONT TEMPERATURES WILL WARM TO NEAR NORMAL.
TUESDAY THROUGH FRIDAY...THE UPPER TROUGH OVER THE GREAT LAKES
REGION EXTENDING INTO THE EASTERN U.S. AND THE UPPER RIDGE MOVING
OVER THE WESTERN U.S. WILL BOTH BEGIN TO PUSH EASTWARD TOWARDS THE
LATTER PART OF THE EXTENDED. MEANWHILE...THE CWA WILL BE UNDER
NORTHWEST FLOW ALOFT WITH A FEW MID-UPPER LEVEL SHORTWAVE TROUGHS
CIRCULATING THROUGH THE CWA. THE EXTENDED SHOULD REMAIN DRY AS OF
RIGHT NOW...SINCE SOUNDINGS LOOK DRY AT THE LOW LEVELS THROUGHOUT
THE PERIOD.
THE BACK DOOR COLD FRONT AHEAD OF THE FIRST WAVE WILL MOVE THROUGH
THE CWA TUESDAY NIGHT/WEDNESDAY MORNING...BRINGING IN COOLER
TEMPERATURES. THE GFS IS IN BETTER AGREEMENT WITH THE ECMWF
TONIGHT... AS OPPOSED TO LAST NIGHT...WITH THE COLD AIR MOVING IN.
DUE TO THIS...LOADED CONSALL FOR THE HIGHS ON WEDNESDAY AS THE
ALLBLEND SOLUTION SEEMED TOO WARM. THE NEW ECMWF ALSO HAS ANOTHER
SURGE OF COLD AIR MOVING INTO THE CWA ON THURSDAY. HOWEVER...GIVEN
THAT THE GFS WAS NOT ON BOARD WITH THIS TONIGHT...WHICH INCREASES
UNCERTAINTY AT THIS POINT...DECIDED TO GO WITH THE ALLBLEND SOLUTION
FOR THURSDAY. THIS COULD CHANGE IN THE NEXT FEW DAYS DEPENDING ON
HOW MODELS COME INTO AGREEMENT WITH ONE ANOTHER. CLOUDS WILL
INCREASE ON WEDNESDAY AS THE UPPER LEVEL DISTURBANCE MOVES THROUGH
AND SOUNDINGS SATURATE AT THE MID TO UPPER LEVELS. ANOTHER WEAK
UPPER LEVEL DISTURBANCE WILL MOVE THROUGH THE CWA ON FRIDAY
ACCORDING TO THE GFS. THE ECMWF DOES NOT REALLY HAVE THIS FEATURE AT
THE MOMENT WITH THE RIDGE MOVING EAST...SO NOT SURE AT THIS POINT
HOW THIS WILL AFFECT CLOUD COVER AND/OR TEMPERATURES FOR FRIDAY...SO
WENT WITH THE ALLBLEND SOLUTION FOR DAY 7.
TEMPERATURES THROUGHOUT THE EXTENDED WILL START OUT NEAR TO ABOVE
NORMAL...WITH HIGHS IN THE MID 40S TO LOW 50S ON TUESDAY. THE COLDER
AIR MOVING IN ON WEDNESDAY WILL REALLY AFFECT THE EASTERN COUNTIES
IN THE CWA...WITH HIGHS IN THE LOW TO UPPER 30S...WHILE THE REST OF
THE CWA WILL HAVE HIGHS IN THE LOW TO MID 40S. TEMPERATURES WILL
START TO WARM UP TOWARDS THE END OF NEXT WEEK...WITH HIGHS IN THE
MID TO UPPER 40S ON THURSDAY AND HIGHS IN THE LOW TO MID 50S ON
FRIDAY. LOWS WILL BE IN THE TEENS TO 20S THROUGHOUT THE EXTENDED.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SUNDAY AFTERNOON)
ISSUED AT 1044 AM MST SAT DEC 28 2013
VFR TO MVFR CONDITIONS EXPECTED AT GLD AND MCK THROUGH THE TAF
PERIOD. VFR CONDITIONS THIS MORNING WILL HOLD THROUGH THE EARLY
AFTERNOON. COLD FRONT DROPPING SOUTH ACROSS THE HIGH PLAINS WILL
BRING A WIND SHIFT AND DRAMATIC INCREASE IN WINDS...WITH GUSTS OVER
30KTS AROUND 21-23Z. WHILE GUSTS COULD CAUSE SOME BLOWING
DUST...BELIEVE ANY VISIBILITY-OBSTRUCTING BLOWING DUST WILL BE
BRIEF. WINDS WILL CONTINUE THROUGH THE NIGHT...GRADUALLY DECREASING
TOWARDS DAWN. EARLY THIS EVENING STRATUS WILL MOVE IN RESULTING IN
MVFR CEILINGS BECOMING VFR. A FEW FLURRIES ARE ALSO POSSIBLE THIS
EVENING AT GLD...BUT CHANCES ARE LOW SO DID NOT INCLUDE A MENTION IN
THIS ISSUANCE.
&&
.GLD WATCHES/WARNINGS/ADVISORIES...
KS...NONE.
CO...NONE.
NE...NONE.
&&
$$
SHORT TERM...JJM
LONG TERM...JTL/ALW
AVIATION...JJM
AREA FORECAST DISCUSSION
NWS DODGE CITY KS
207 PM CST Sat Dec 28 2013
...Updated long term section...
.SYNOPSIS...
ISSUED AT 1106 AM CST SAT DEC 28 2013
At 12z Saturday a -25c 500mb low was located over west central
Texas. An upper level trough extended from southern Saskatchewan
into southern California. 140 to 160 meter 12hour 500mb height
falls observed across eastern Montana which was just east of
this upper trough. A 700mb baroclinic zone was also located across
eastern Montana with a pool of higher dewpoints observed near this
baroclinic zone. A the surface at 12z Saturday an area of low
pressure was located across southern North Dakota with a cold
front extending west into southeast Montana. Behind this cold
front the surface observations reported gusty northwest winds of
30 to near 40kts, tight surface pressure gradient and a 3 hour
surface pressure fall of 5 to near 10mb.
&&
.SHORT TERM...(This evening through Sunday)
ISSUED AT 159 PM CST SAT DEC 28 2013
Windy conditions will develop behind a cold front that will cross
western Kansas early tonight. Both the 12z NAM and GFS have a
decent handle with th cold front location based on 18z
verification. Also based on the 18z verification it also appears
that the 12z NAM had a slightly better handle with the cold air
located behind this front. The NAM also was doing a good job with
the very windy conditions which were developing in the wake of
this cold front based on the boundary layer and mean mixed layer
winds at 18z. Given this will use the mean mixed layer winds and
boundary layer mean winds from the NAM as a guide for wind speeds
overnight as this cold front crosses western Kansas. At this time
it appears that sustained winds of near 30mph will be possible for
a few hours behind this front front between 03z and 09z, however
given how brief these stronger winds will be, marginal sustained
wind speeds, and good collaboration with our surrounding offices
have decided to hold off issuing a wind advisory for western
Kansas tonight.
Gusty north winds at 20 to 30 mph will continue through early
Sunday morning. Given the cold air advection forecast overnight
and how the NAM verified with the cold air across South Dakota and
Montana earlier today will trend overnight lows towards the cooler
MET solution on lows tonight. Given these overnight lows in the
teens and gusty north winds at 20 to 30 mph the wind chills late
tonight/early Sunday will range from 5 to 10 degrees below zero.
There will also be a chance for some very light precipitation
overnight, mainly along and west of highway 83. In this area the
model soundings indicated the 850mb to 700mb level saturates as
improving frontogenesis develops ahead of an approaching upper
level trough.
On Sunday the gusty north winds will gradually subside during the
afternoon as an area of high pressure at the surface begins to
build into the area from the north. Despite the chance for some
breaks of sun during the afternoon, the 925mb and 850mb
temperatures at 00z Monday suggested highs wills struggle to climb
into the mid 20s to near 30. The warmer temperatures Sunday
afternoon are expected to be located in west central Kansas.
.LONG TERM...(Sunday night through Saturday)
ISSUED AT 206 PM CST SAT DEC 28 2013
he Central High Plains will be in northwest flow aloft as the long
term starts out with mid levels of the atmosphere fairly dry. An
area of high pressure at the surface will be located across the Mid
Mississippi Valley with its axis stretching eastward across Kansas
Sunday evening. Sunday night looks to be cold as mostly clear skies
and light winds are expected allowing for good radiative cooling.
Lows will generally range from the upper single digits across
central Kansas to mid teens across far western Kansas. A warming
trend is expected Monday and Tuesday with winds generally from a
westerly direction. With this downslope component of the wind and
warmer mid level temperatures, highs Monday and Tuesday will reach
into the 40s with a few places across far western Kansas reaching
into the lower 50s Tuesday afternoon. Lows Monday night will be in
the lower 20s.
An upper level shortwave moves through the Northern Plains Tuesday
night and helps push a surface cold front through the Central High
Plains. This will shift winds to more of a northerly direction. The
mid levels of the atmosphere will be fairly dry during this time
frame with partly cloudy skies continuing across southwest Kansas. A
second upper level shortwave is then progged to move through
Nebraska on Wednesday. This will bring a reinforcing shot of cold
air plus a chance of light snow across Nebraska and northern
Kansas. I have continued a slight chance of snow across the I-70
corridor with increasing cloudiness. Otherwise partly cloudy skies
will continue across the forecast area. Lows Wednesday and Thursday
morning will generally range form the upper teens across central
Kansas to upper 20s across far southwestern Kansas. High Wednesday
are only expected to reach into the lower to mid 30s with the
exception of far western Kansas where upper 30s and lower 40s will
be possible.
The remainder of the forecast period looks dry with more of a west
to east zonal pattern developing in the mid to upper levels. High
pressure at the surface will build into the Mississippi Valley with
lee toughing developing across eastern Colorado. Highs Thursday and
Friday will generally be in the 40s with a few places across far
western Kansas reaching into the lower 50s Friday afternoon. Lows
Friday morning look to dip into the lower to mid 20s.
&&
.AVIATION...(For the 18Z TAFS through 18Z Sunday afternoon)
ISSUED AT 1106 AM CST SAT DEC 28 2013
The 12z NAM and latest HRRR both appear to be doing a decent job
on the location of a cold front at 15z. Will therefore use these
for timing of the frontal passage as it crosses western Kansas
early this evening. With this in mind frontal passage will occur
at HYS and GCK around 01z and then DDC around 03z. Once this front
passages north winds will increase into the 20 to near 25kt range.
The stronger winds overnight are expected between 06z and 12z. Low
clouds are also expected to spread across western Kansas overnight
behind this front. Based on model soundings will trend towards a
brief period of MVFR cigs behind this front followed by low VFR
cigs after 06z and persisting through 18z.
&&
.PRELIMINARY POINT TEMPS/POPS...
DDC 14 25 10 46 / 0 0 0 0
GCK 14 27 12 47 / 10 10 0 0
EHA 17 28 17 47 / 10 20 0 0
LBL 16 28 11 47 / 0 10 0 0
HYS 14 25 8 45 / 0 0 0 0
P28 17 26 12 42 / 10 0 0 0
&&
.DDC WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...Burgert
SHORT TERM...Burgert
LONG TERM...Hovorka_42
AVIATION...Burgert
AREA FORECAST DISCUSSION
NWS DODGE CITY KS
203 PM CST Sat Dec 28 2013
...Updated short term discussion...
.SYNOPSIS...
ISSUED AT 1106 AM CST SAT DEC 28 2013
At 12z Saturday a -25c 500mb low was located over west central
Texas. An upper level trough extended from southern Saskatchewan
into southern California. 140 to 160 meter 12hour 500mb height
falls observed across eastern Montana which was just east of
this upper trough. A 700mb baroclinic zone was also located across
eastern Montana with a pool of higher dewpoints observed near this
baroclinic zone. A the surface at 12z Saturday an area of low
pressure was located across southern North Dakota with a cold
front extending west into southeast Montana. Behind this cold
front the surface observations reported gusty northwest winds of
30 to near 40kts, tight surface pressure gradient and a 3 hour
surface pressure fall of 5 to near 10mb.
&&
.SHORT TERM...(This evening through Sunday)
ISSUED AT 159 PM CST SAT DEC 28 2013
Windy conditions will develop behind a cold front that will cross
western Kansas early tonight. Both the 12z NAM and GFS have a
decent handle with th cold front location based on 18z
verification. Also based on the 18z verification it also appears
that the 12z NAM had a slightly better handle with the cold air
located behind this front. The NAM also was doing a good job with
the very windy conditions which were developing in the wake of
this cold front based on the boundary layer and mean mixed layer
winds at 18z. Given this will use the mean mixed layer winds and
boundary layer mean winds from the NAM as a guide for wind speeds
overnight as this cold front crosses western Kansas. At this time
it appears that sustained winds of near 30mph will be possible for
a few hours behind this front front between 03z and 09z, however
given how brief these stronger winds will be, marginal sustained
wind speeds, and good collaboration with our surrounding offices
have decided to hold off issuing a wind advisory for western
Kansas tonight.
Gusty north winds at 20 to 30 mph will continue through early
Sunday morning. Given the cold air advection forecast overnight
and how the NAM verified with the cold air across South Dakota and
Montana earlier today will trend overnight lows towards the cooler
MET solution on lows tonight. Given these overnight lows in the
teens and gusty north winds at 20 to 30 mph the wind chills late
tonight/early Sunday will range from 5 to 10 degrees below zero.
There will also be a chance for some very light precipitation
overnight, mainly along and west of highway 83. In this area the
model soundings indicated the 850mb to 700mb level saturates as
improving frontogenesis develops ahead of an approaching upper
level trough.
On Sunday the gusty north winds will gradually subside during the
afternoon as an area of high pressure at the surface begins to
build into the area from the north. Despite the chance for some
breaks of sun during the afternoon, the 925mb and 850mb
temperatures at 00z Monday suggested highs wills struggle to climb
into the mid 20s to near 30. The warmer temperatures Sunday
afternoon are expected to be located in west central Kansas.
.LONG TERM...(Sunday through Friday)
ISSUED AT 154 AM CST SAT DEC 28 2013
Not a whole lot has changed in the overall forecast thinking
regarding the Sunday through Monday Night forecast. Only negligible
changes were made to the grids Sunday and Sunday Night as the
inherited forecast was on track. One of the challenges Sunday will
be how quickly the winds will decrease through the day. The MSLP
gradient will relax as the ridge axis approaches western Kansas by
afternoon. Temperatures will likely fall fairly quickly at sunset
Sunday Night as winds drop off substantially. We should see
temperatures well into the mid to upper teens by mid to late
evening...before stabilizing in the 06-12z time frame in the 9 to
15F range across much of the southwest Kansas region. Winds will
increase just a bit 09-12Z from the southwest as a new lee trough
forms in response to the next northwest flow jet streak.
The Monday forecast temperature was increased 3-5 degF across the
board as it now looks like the west-northwest boundary layer
downslope momentum will really eat away at this cold airmass...and
quickly... especially west of Highway 283. An improvement of 35 degF
over the morning lows is quite likely with afternoon temperatures
reaching the 45-47 degF range west of a Meade-Dodge City-Lacrosse
line. The surface arctic front will become quasi-stationary across
the Northern Plains Tuesday, but still north of the southwest Kansas
region so Tuesday looks fairly pleasant all things considered with
temperatures improving to the upper 40s/lower 50s for much of the
area. This front will move south Tuesday Night, per the latest ECMWF
and GFS, and will usher in another round of cold air. It was a
collaborative decision among four of the offices (DDC, GLD, GID,
ICT) to go with colder CONSALL guidance instead of the baseline
AllBlend given the degree of cold air and higher confidence in the
shallow arctic air affecting the Central Plains mid-week. The
remainder of the tail-end of the Long Term was unchanged from the
AllBlend guidance...but this forecast is very low confidence
depending on what evolves with the arctic airmass. Colder
temperatures may be forecast for Thursday and beyond in future
updates.
&&
.AVIATION...(For the 18Z TAFS through 18Z Sunday afternoon)
ISSUED AT 1106 AM CST SAT DEC 28 2013
The 12z NAM and latest HRRR both appear to be doing a decent job
on the location of a cold front at 15z. Will therefore use these
for timing of the frontal passage as it crosses western Kansas
early this evening. With this in mind frontal passage will occur
at HYS and GCK around 01z and then DDC around 03z. Once this front
passages north winds will increase into the 20 to near 25kt range.
The stronger winds overnight are expected between 06z and 12z. Low
clouds are also expected to spread across western Kansas overnight
behind this front. Based on model soundings will trend towards a
brief period of MVFR cigs behind this front followed by low VFR
cigs after 06z and persisting through 18z.
&&
.PRELIMINARY POINT TEMPS/POPS...
DDC 14 25 10 45 / 0 0 0 0
GCK 14 27 12 47 / 10 10 0 0
EHA 17 28 17 47 / 10 20 0 0
LBL 16 28 10 47 / 0 10 0 0
HYS 14 25 8 45 / 0 0 0 0
P28 17 26 12 41 / 10 0 0 0
&&
.DDC WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...Burgert
SHORT TERM...Burgert
LONG TERM...Umscheid
AVIATION...Burgert
AREA FORECAST DISCUSSION
NWS DODGE CITY KS
1109 AM CST Sat Dec 28 2013
...Updated synopsis and aviation discussion...
.SYNOPSIS...
ISSUED AT 1106 AM CST SAT DEC 28 2013
At 12z Saturday a -25c 500mb low was located over west central
Texas. An upper level trough extended from southern Saskatchewan
into southern California. 140 to 160 meter 12hour 500mb height
falls observed across eastern Montana which was just east of
this upper trough. A 700mb baroclinic zone was also located across
eastern Montana with a pool of higher dewpoints observed near this
baroclinic zone. A the surface at 12z Saturday an area of low
pressure was located across southern North Dakota with a cold
front extending west into southeast Montana. Behind this cold
front the surface observations reported gusty northwest winds of
30 to near 40kts, tight surface pressure gradient and a 3 hour
surface pressure fall of 5 to near 10mb.
&&
.SHORT TERM...(Today and tonight)
ISSUED AT 100 AM CST SAT DEC 28 2013
Short range models indicate the closed off upper level low in west
Texas lifting northeast into southern Oklahoma today then kicking
eastward into Arkansas Saturday night. Meanwhile, the upper level
shortwave in the Pacific Northwest will dig southeast into the
central Rockies and Four Corners Region today bringing snow chances
to the high country late this afternoon into tonight. Otherwise, a
weak unorganized flow aloft and an extremely dry lower/mid levels
will result in dry conditions persisting across western Kansas
through Saturday evening. There is an outside shot for snow
flurries across west central and extreme southwest Kansas after
midnight Saturday night as the upper level shortwave kicks out of
the Rockies into the Western High Plains. However, no accumulations
are expected through early Sunday morning.
Similar temperatures are expected for highs from yesterday into
today as a prevailing lee side trough continues to influence a
light southwest flow across western Kansas through this afternoon.
This will reinforce the warmer air mass in place across western
Kansas resulting in highs up into the 50s(F) and the lower 60s(F).
The coolest temperatures, with a few upper 40s(F) possible, will
once again reside across a narrow corridor from far eastern
portions of southwest Kansas just east of Dodge City northeastward
into central Kansas near Larned where the last of the lingering
snowpack resides. Much colder air will spill southward into
western Kansas Saturday night in wake of a strong cold front
pushing through early to mid evening. The NAM/GFS show the 0C
isotherm diving well into north Texas with H85 temperatures around
or just under 10C below across central and much of southwest
Kansas. Look for lows down into the Teens(F) across west central
and central Kansas to near 20F possible closer to the Oklahoma
border.
.LONG TERM...(Sunday through Friday)
ISSUED AT 154 AM CST SAT DEC 28 2013
Not a whole lot has changed in the overall forecast thinking
regarding the Sunday through Monday Night forecast. Only negligible
changes were made to the grids Sunday and Sunday Night as the
inherited forecast was on track. One of the challenges Sunday will
be how quickly the winds will decrease through the day. The MSLP
gradient will relax as the ridge axis approaches western Kansas by
afternoon. Temperatures will likely fall fairly quickly at sunset
Sunday Night as winds drop off substantially. We should see
temperatures well into the mid to upper teens by mid to late
evening...before stabilizing in the 06-12z time frame in the 9 to
15F range across much of the southwest Kansas region. Winds will
increase just a bit 09-12Z from the southwest as a new lee trough
forms in response to the next northwest flow jet streak.
The Monday forecast temperature was increased 3-5 degF across the
board as it now looks like the west-northwest boundary layer
downslope momentum will really eat away at this cold airmass...and
quickly... especially west of Highway 283. An improvement of 35 degF
over the morning lows is quite likely with afternoon temperatures
reaching the 45-47 degF range west of a Meade-Dodge City-Lacrosse
line. The surface arctic front will become quasi-stationary across
the Northern Plains Tuesday, but still north of the southwest Kansas
region so Tuesday looks fairly pleasant all things considered with
temperatures improving to the upper 40s/lower 50s for much of the
area. This front will move south Tuesday Night, per the latest ECMWF
and GFS, and will usher in another round of cold air. It was a
collaborative decision among four of the offices (DDC, GLD, GID,
ICT) to go with colder CONSALL guidance instead of the baseline
AllBlend given the degree of cold air and higher confidence in the
shallow arctic air affecting the Central Plains mid-week. The
remainder of the tail-end of the Long Term was unchanged from the
AllBlend guidance...but this forecast is very low confidence
depending on what evolves with the arctic airmass. Colder
temperatures may be forecast for Thursday and beyond in future
updates.
&&
.AVIATION...(For the 18Z TAFS through 18Z Sunday afternoon)
ISSUED AT 1106 AM CST SAT DEC 28 2013
The 12z NAM and latest HRRR both appear to be doing a decent job
on the location of a cold front at 15z. Will therefore use these
for timing of the frontal passage as it crosses western Kansas
early this evening. With this in mind frontal passage will occur
at HYS and GCK around 01z and then DDC around 03z. Once this front
passages north winds will increase into the 20 to near 25kt range.
The stronger winds overnight are expected between 06z and 12z. Low
clouds are also expected to spread across western Kansas overnight
behind this front. Based on model soundings will trend towards a
brief period of MVFR cigs behind this front followed by low VFR
cigs after 06z and persisting through 18z.
&&
.PRELIMINARY POINT TEMPS/POPS...
DDC 57 17 25 10 / 0 0 10 0
GCK 63 17 26 12 / 0 10 10 0
EHA 63 18 30 17 / 0 10 10 0
LBL 61 18 26 10 / 0 10 10 0
HYS 65 15 24 8 / 0 0 0 0
P28 60 18 24 12 / 0 0 0 0
&&
.DDC WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...Burgert
SHORT TERM...JJohnson
LONG TERM...Umscheid
AVIATION...Burgert
AREA FORECAST DISCUSSION
NWS NEW ORLEANS LA
1134 AM CST SAT DEC 28 2013
.AVIATION...
BASED ON SHORT-TERM RADAR TRENDS...MORE MODERATE RAIN AREAS WERE
SLOWLY SHRINKING WITH MUCH OF THE RAIN SHIELD BECOMING -RA IN THE
NEXT 1-2 HOURS. IFR CEILINGS WERE ALSO LIFTING OUTSIDE HEAVIER
RAIN CLUSTERS. LATEST RUC RUN SHOWS RAIN BRIEFLY TAPERING THEN
RETURNING IN THE AFTERNOON WITH LIGHT AMOUNTS FROM ELEVATED
CEILINGS AROUND 10KFT. WILL SHOW OPTMISTIC TREND OF IMPROVEMENT TO
VFR CIGS/VSBY THOUGH MAINTAINING -RA THROUGH EARLY EVENING...THEN
GENERAL VFR CAVOK/NSW AFTER 02Z. EXCEPTION MAY BE KNEW WITH MARINE
INFLUENCES KEEPING LOW CLOUD DECK LONGER INTO THE NIGHT. VFR CAVOK
CONDITIONS EXPECTED SUNDAY. 24/RR
&&
.PREV DISCUSSION... /ISSUED 401 AM CST SAT DEC 28 2013/
SHORT TERM...
LATEST ANALYSIS SHOWS CLOSED UPPER LEVEL LOW CENTERED NEAR MIDLAND
TEXAS AND A WEAK SURFACE TROUGH OVER THE SOUTHWEST GULF. WATER VAPOR
IMAGERY DEPICTS INCREASING SUBTROPICAL MOISTURE SURGING
NORTHEASTWARD FROM THE PACIFIC TO THE NORTHERN GULF COAST. RADAR
SHOWS NEARLY COMPLETE AREAL COVERAGE OF STRATIFORM SHOWERS ACROSS
THE CWA. WITH THIS EXPECTED TO CONTINUE MUCH OF THE DAY...INCREASED
POPS TO 100 PERCENT AREAWIDE. THERE COULD BE PERIODS OF MODERATE TO
OCCASIONALLY HEAVY RAIN LATER TODAY AS THE SURFACE LOW DEEPENS AND
TRACKS NORTHEAST ACROSS THE COASTAL WATERS. OVERALL RAINFALL TOTALS
STILL LOOK TO BE AROUND 1 TO 2 INCHES WITH POSSIBLY HIGHER AMOUNTS
ALONG THE COAST. TEMPERATURES TODAY WILL ONLY MODERATE SLIGHTLY WITH
SUCH EXTENSIVE RAIN COVERAGE...SO HAVE KEPT HIGHS IN THE LOWER 50S.
AN UPPER LEVEL TROUGH DIVING SOUTH ACROSS THE CENTRAL PLAINS TONIGHT
WILL ABSORB THE CLOSED LOW AS IT MOVES ACROSS TX/OK/AR. WE WILL BE
DRYING OUT ON SUNDAY AS THE OPENING UPPER LOW KICKS NORTHEAST AND
BRINGS IN SURFACE RIDGE. HIGHS STILL BELOW NORMAL BUT WARMER THAN
THE LAST FEW DAYS.
LONG TERM...
THERE WILL BE LITTLE TIME BEFORE A REINFORCING BOUNDARY MOVES IN.
THIS NEXT FRONT SHOULD SWING THROUGH MONDAY AS THE MAIN UPPER LEVEL
TROUGH FROM CANADA DIGS OVER THE SOUTHEAST. WILL KEEP THE FORECAST
DRY ON MONDAY AS ECMWF AND GFS SUGGEST NO RAIN AND MOISTURE RETURN
IS NOT EXPECTED TO OCCUR BETWEEN SYSTEMS. TEMPERATURES WILL THUS
REMAIN WELL BELOW NORMAL THROUGH TUESDAY AS HIGH PRESSURE BUILDS IN.
THE REMAINDER OF THE FORECAST IS A BIT UNCERTAIN. THE ECMWF SUGGESTS
A NEAR REPEAT OF TODAY ON WEDNESDAY WITH UPPER LOW PULLING OUT OF
TEXAS WITH A SURFACE LOW TRACKING ACROSS THE GULF COAST. THE GFS/S
PREVIOUS RUN SHOWED SOMETHING SIMILAR BUT HAS BACKED OFF SOLUTION
AND NOW JUST SHOWS AN OPEN WAVE BRINGING A FRONT THROUGH AND THUS
KEEPS THE AREA DRY. WITH SUCH LARGE DISCREPANCIES IN POPS...HAVE
DROPPED PREVIOUS FORECAST BUT STILL HAVE CHANCE POPS IN THE THE
ZONES.
MEFFER
AVIATION...SHRA CONTINUE TO INCREASE ACROSS THE REGION AND AS THE
ATMOSPHERE MOISTENS UP THE LOW CLOUDS WILL CONTINUE TO BUILD
EVENTUALLY LOWERING TO AROUND 700-1K FT. LOW CLOUDS AND RAIN WILL
IMPACT ALL TERMINALS MUCH OF THE DAY. CONDITIONS WONT SIGNIFICANTLY
IMPROVE UNTIL AT LEAST 00Z IF NOT LATER. /CAB/
MARINE...A GULF LOW IS ALREADY DEVELOPING OVER THE N-CNTRL GULF AND
WILL DEEPEN THROUGH THE DAY AS IT MOVES CLOSE TO THE MOUTH OF THE
RIVER. THIS IS ALREADY LEADING TO STRONG WINDS ERLY WINDS OVER THE
WATERS EAST OF THE MS RIVER AND NRLY WINDS WEST OF THE RIVER. A SCY
IS ALREADY IN PLACE FOR ALL OF THE OPEN WATERS FOR WINDS OF 20-25
KTS. THE LOW WILL PULL OFF TO THE NORTHEAST QUICKLY TONIGHT AND
WINDS WILL BEGIN TO BACK OFF BUT THIS WILL BE SHORT LIVED. ANOTHER
SHOT OF COLD AIR WILL WORK DOWN INTO THE REGION MON NIGHT AND THIS
WILL LEAD TO A RETURN OF STRONG OFFSHORE WINDS. MDLS THEN BEGIN TO
HAVE SIGNIFICANT DIFFERENCES AFTER THE NEW YEAR. THERE ARE
INDICATIONS THAT ANOTHER GULF LOW COULD DEVELOP ON NEW YEARS DAY
WITH ANOTHER STRONG SHOT OF COLD AIR THU/THU NIGHT LEADING TO
ADDITIONAL STRONG WINDS. /CAB/
DECISION SUPPORT...
DSS CODE...BLUE.
DEPLOYED...NONE.
ACTIVATION...NONE.
ACTIVITIES...SLURRY SUPPORT...SMALL CRAFT ADV
DECISION SUPPORT SERVICES (DSS) CODE LEGEND
GREEN = NO WEATHER IMPACTS THAT REQUIRE ACTION
BLUE = LONG FUSED WATCH/WARNING/ADVISORY IN EFFECT OR HIGH
VISIBILITY EVENT
YELLOW = HEIGHTENED IMPACTS WITH SHORT FUSED
WATCH/WARNING/ADVISORY ISSUANCES; RADAR SUPPORT
ORANGE = HIGH IMPACTS - SLIGHT TO MODERATE RISK SEVERE; NEARBY
TROPICAL EVENTS; HAZMAT OR OTHER LARGE EPISODES
RED = FULL ENGAGEMENT FOR MODERATE TO HIGH RISK SVR
AND/OR DIRECT TROPICAL THREATS; EVENTS OF NATIONAL
SIGNIFICANCE
&&
.PRELIMINARY POINT TEMPS/POPS...
MCB 51 37 61 39 / 100 70 10 10
BTR 52 40 63 42 / 100 70 10 10
ASD 53 42 62 41 / 100 80 10 10
MSY 53 43 61 44 / 100 80 10 10
GPT 53 44 62 43 / 100 90 10 10
PQL 53 45 62 42 / 100 90 10 10
&&
.LIX WATCHES/WARNINGS/ADVISORIES...
LA...NONE.
GM...SMALL CRAFT ADVISORY UNTIL 9 PM SATURDAY FOR THE FOLLOWING
ZONES: COASTAL WATERS FROM BOOTHVILLE LA TO THE SOUTHWEST
PASS OF THE MISSISSIPPI RIVER OUT 20 NM...COASTAL WATERS
FROM PASCAGOULA MS TO STAKE ISLAND LA FROM 20 TO 60
NM...COASTAL WATERS FROM PASCAGOULA MS TO STAKE ISLAND LA
OUT 20 NM...COASTAL WATERS FROM PORT FOURCHON TO LOWER
ATCHAFALAYA RIVER FROM 20 TO 60 NM...COASTAL WATERS FROM
PORT FOURCHON TO LOWER ATCHAFALAYA RIVER OUT 20
NM...COASTAL WATERS FROM STAKE ISLAND LA TO THE SOUTHWEST
PASS OF THE MISSISSIPPI RIVER FROM 20 TO 60 NM...COASTAL
WATERS FROM THE SOUTHWEST PASS OF THE MISSISSIPPI RIVER TO
PORT FOURCHON FROM 20 TO 60 NM...AND COASTAL WATERS FROM
THE SOUTHWEST PASS OF THE MISSISSIPPI RIVER TO PORT
FOURCHON OUT 20 NM.
MS...NONE.
GM...SMALL CRAFT ADVISORY UNTIL 9 PM SATURDAY FOR THE FOLLOWING
ZONES: COASTAL WATERS FROM BOOTHVILLE LA TO THE SOUTHWEST
PASS OF THE MISSISSIPPI RIVER OUT 20 NM...COASTAL WATERS
FROM PASCAGOULA MS TO STAKE ISLAND LA FROM 20 TO 60
NM...COASTAL WATERS FROM PASCAGOULA MS TO STAKE ISLAND LA
OUT 20 NM...COASTAL WATERS FROM PORT FOURCHON TO LOWER
ATCHAFALAYA RIVER FROM 20 TO 60 NM...COASTAL WATERS FROM
PORT FOURCHON TO LOWER ATCHAFALAYA RIVER OUT 20
NM...COASTAL WATERS FROM STAKE ISLAND LA TO THE SOUTHWEST
PASS OF THE MISSISSIPPI RIVER FROM 20 TO 60 NM...COASTAL
WATERS FROM THE SOUTHWEST PASS OF THE MISSISSIPPI RIVER TO
PORT FOURCHON FROM 20 TO 60 NM...AND COASTAL WATERS FROM
THE SOUTHWEST PASS OF THE MISSISSIPPI RIVER TO PORT
FOURCHON OUT 20 NM.
&&
$$
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
446 PM EST SAT DEC 28 2013
.SHORT TERM...(THIS EVENING THROUGH SUNDAY)
ISSUED AT 419 PM EST SAT DEC 28 2013
A STALLED FRONTAL BOUNDARY OVER SOUTHERN LAKE SUPERIOR AND NORTHERN
UPPER MICHIGAN HAS LED TO DREARY CONDITIONS FOR MUCH OF UPPER
MICHIGAN TODAY. ON THE PLUS SIDE...TEMPERATURES HAVE BEEN IN THE
LOW TO MID 30S ALONG AND SOUTH OF THE BOUNDARY WHERE THERE HAVE
EVEN BEEN A FEW PEAKS OF SUNSHINE. JUST TO THE NORTH OF THE
BOUNDARY...FAVORABLE EASTERLY FLOW OFF LAKE SUPERIOR HAS LED TO
SOME FZDZ...FOG...AND -SHSN OVER THE KEWEENAW PENINSULA. A SPOTTER
REPORT AROUND 3PM INDICATED A SLIGHT GLAZE IN MOHAWK SHORTLY
AFTER THE VISIBILITY REALLY DROPPED AT KCMX. THINK THAT
FREEZING DRIZZLE WILL REMAIN A THREAT OVER THE NEXT COUPLE OF HOURS
AND EVEN DRIFT SOUTHEAST THROUGH THE EVENING...AS MODELS SHOW A
LACK OF ICE CRYSTALS IN THE CLOUDS BEFORE THE MAIN PRECIPITATION
ARRIVES FROM SOUTHERN CANADA LATE THIS EVENING. ALSO FOR THIS
EVENING...DID ADD SOME PATCHY FOG OVER THE SOUTHEAST PART OF THE
CWA WHERE WINDS WILL BE LIGHT AND THERE HAVE BEEN SOME BREAKS IN
THE CLOUDS.
THE LOW THAT IS CURRENTLY CENTERED IN SOUTH CENTRAL MINNESOTA WILL
CONTINUE EAST TONIGHT AND SUNDAY...BEING CENTERED JUST NORTH OF LAKE
ONTARIO BY 00Z MONDAY. AS THIS LOW SWEEPS EAST...AN AREA OF SNOW
(CURRENTLY IN SOUTHWEST ONTARIO AND ALSO ENTERING NORTHWEST
MINNESOTA) WILL SWEEP ACROSS THE UPPER GREAT LAKES LATE THIS
EVENING THROUGH EARLY SUNDAY MORNING. THE SYNOPTIC SNOW WILL BE
AIDED BY THE RIGHT REAR OF THE 110KT UPPER JET THAT SWEEPS ACROSS
TONIGHT. IN ADDITION...POCKET OF 800-600MB FGEN WILL SLIDE THROUGH
WITH THE 850/700MB TROUGH. THUS...EXPECT A PERIOD OF LIGHT SNOW TO
MOVE ACROSS MUCH OF UPPER MICHIGAN FROM WEST TO EAST. WITH THE BEST
FORCING OVER THE NORTHERN HALF OF THE CWA...EXPECT THE BEST SYNOPTIC
SNOWFALL THERE...WHICH WILL BE AIDED BY LAKE ENHANCEMENT. OVER THE
SOUTHERN HALF...ONLY EXPECT A LIGHT DUSTING TO AN INCH AWAY FROM THE
LAKE SUPERIOR INFLUENCES WITH SNOW RATIOS AROUND NORMAL VALUES OF
13-1.
AS FOR THE LAKE ENHANCEMENT...COLD AIR SURGING IN BEHIND THE LOW
(FALLING FROM RAP ANALYZED VALUES OF 0C FROM WEST-EAST OVER THE
CENTRAL U.P. AT 20Z TO -10 TO -16C AT 12Z SUNDAY AND -23C BY 00Z
MONDAY) WILL LEAD TO LAKE ENHANCEMENT FOR AREAS NEAR LAKE SUPERIOR
AS THE WIND DIRECTIONS BECOME FAVORABLE. THE WINDS WILL BE OUT OF
THE NORTHEAST INITIALLY THIS EVENING OVER WESTERN LAKE
SUPERIOR...BUT AS THE SURFACE/925MB LOW MOVES EAST-NORTHEAST THROUGH
NORTHEAST WISCONSIN AND SOUTH CENTRAL UPPER MICHIGAN TONIGHT...THE
WINDS WILL TRANSITION TO THE NORTH OVERNIGHT...NNW SUNDAY
MORNING...AND THEN NW SUNDAY AFTERNOON. THUS...EXPECT THE INITIAL
ENHANCEMENT TO OCCUR LATE IN THE EVENING OVER THE NE FAVORED
LOCATIONS AND THEN TRANSITION WITH THE WINDS INTO SUNDAY MORNING.
THESE STEADY BACKING WINDS WILL LIKELY BE ONE OF THE LIMITING
FACTORS TO HEAVIER SNOWFALL AMOUNTS. THE SECOND ITEM THAT SHOULD
KEEP SNOWFALL AMOUNTS IN THE LES ADVISORY CATEGORY WILL BE THE SHORT
PERIOD WHEN THE LAKE ENHANCEMENT AND LOW LEVEL TEMPERATURE PROFILE
FALL WITHIN THE DGZ. AT MOST LOCATIONS...IT APPEARS LIKE IT WILL
ONLY OCCUR FOR A 3 TO MAYBE 6HOUR PERIOD. THUS...EVEN THOUGH SNOW
RATIOS WILL QUICKLY RISE TO THE LOWER 20S...THEY WILL QUICKLY FALL
ONCE THE DEEPER MOISTURE DEPARTS AND THE INCREASING COLD AIR MOVES
THE CLOUD OUT OF THE DGZ. FINALLY...GUSTY WINDS MAY LIMIT SNOW
RATIOS FROM GROWING MUCH ABOVE 22/23-1 DURING THE FAVORED
PERIOD...EVEN THOUGH ALL OF THE CLOUD IS WITHIN THE DGZ.
OVERALL...ONLY MADE MINOR TWEAKS TO MUCH OF THE SNOWFALL FORECAST
FOR TONIGHT INTO SUNDAY MORNING...LARGELY WITH HANDLING THE TIMING
OF THE CHANGE OVER TO SNOW FROM NORTHWEST TO SOUTHEAST. THE FAVORED
HIGHER TERRAIN LOCATIONS WILL LIKELY SEE AMOUNTS THROUGH SUNDAY
MORNING IN THE 3-8INCH RANGE...WITH THE GREATEST AMOUNTS OVER THE
HURON MOUNTAINS WITH THE LONGER PERIOD OF FAVORABLE WIND
DIRECTIONS. THAT WOULD BE THE ONLY LOCATIONS WHERE SOME CONCERN OF
NEAR WARNING AMOUNT SNOW WOULD OCCUR...BUT THE SOCIETAL IMPACT WILL
BE LIMITED.
DEEPER MOISTURE FROM THE LOW PULLS OUT QUICKLY FROM WEST TO EAST ON
SUNDAY MORNING AND LEADS TO A TRANSITION TO PURE LAKE EFFECT. WITH
THAT DEEPER MOISTURE DEPARTING...MODELS ARE ONLY SHOWING MOISTURE
AND INVERSION HEIGHTS AROUND 4KFT...BUT WITH LAKE INDUCED
EQUILIBRIUM LEVELS AROUND 5-6KFT...COULD STILL BE SOME STRONGER SNOW
SHOWERS. BUT WITH COLDER AIR CONTINUING TO SURGE IN...MUCH OF THE
CLOUD LAYER WILL MOVE TO THE TOP OF OR ABOVE THE DGZ...WHICH SHOULD
LEAD TO A TRANSITION TO MORE OF COLUMN/PLATES. THEREFORE...WILL
CONTINUE THE IDEA OF LOWERING SNOW RATIOS TO THE HIGH TEENS OR
AROUND 20-1 FROM WEST TO EAST THROUGH THE DAY SUNDAY. THIS SHOULD
LEAD TO LESSER SNOWFALL AMOUNTS IN THE AFTERNOON...WHICH WILL STILL
BE AIDED BY SLOWLY BACKING WINDS TO THE NORTHWEST. OVERALL...HAVE
AFTERNOON AMOUNTS OF 1-2 INCHES IN MOST LOCATIONS...WITH SLIGHTLY
HIGHER VALUES OVER WESTERN ALGER COUNTY. THEREFORE...WILL KEEP LES
ADVISORIES AS IS...ALTHOUGH THE LONG TERM DID MAKE SOME ADJUSTMENTS
TO ALGER TO EXTEND INTO MONDAY. THINK THAT COVERS THE OVERALL IDEA
VERY WELL...SINCE THE NEGATIVES WITH SNOW RATIOS AND BACKING WINDS
SHOULD LIMIT THE POTENTIAL FOR 12HR SNOW AMOUNTS REACHING WARNING
VALUES.
THE COLD AIR SURGING IN WILL LEAD TO FALLING TEMPERATURES STARTING
LATE THIS EVENING OVER THE WEST AND PUSHING ACROSS THE REST OF THE
AREA THROUGH THE NIGHT. OVERNIGHT LOWS FOR TONIGHT AND HIGHS FOR
TOMORROW ARE FAIRLY TRICKY...AS THEY BOTH WILL LIKELY OCCUR DURING
THE TWO HOUR OVERLAP BETWEEN 12-14Z. THUS...TRIED TO FOCUS ON TEMPS
DURING THAT PERIOD TO USE FOR SIMILAR VALUES. WITH THE COLD AIR
CONTINUING TO SURGE IN THROUGH THE DAY ON SUNDAY...EXPECT STEADY OR
SLOWLY FALLING TEMPERATURES THROUGH THE REST OF THE DAY ON
SUNDAY. AFTERNOON VALUES OVER THE WEST WILL BE IN THE LOWER SINGLE
DIGITS ABOVE ZERO AND AROUND 10 DEGREES OVER THE EAST HALF.
FACTORING IN WIND CHILLS...TOMORROW AFTERNOON WILL FEEL ABOUT 50
DEGREES COLDER THAN THIS PAST AFTERNOON.
.LONG TERM...(SUNDAY NIGHT THROUGH SATURDAY)
ISSUED AT 445 PM EST SAT DEC 28 2013
SUN NIGHT INTO MONDAY...ENHANCED LOW-LEVEL CONVERGENCE FROM
DEVELOPING LAND BREEZES AND LAKE-INDUCED TROUGHING WILL FAVOR
ALGER...NRN SCHOOLCRAFT AND LUCE COUNTIES FOR POTENTIAL ADVISORY
CRITERIA SNOWFALL. LES ADVISORIES WILL THEN LIKELY BE NEEDED FOR
THAT PORTION OF THE NE CWA WITH ADDITIONAL ACCUMULATIONS IN THE 3 TO
8 INCH RANGE FROM SUN NIGHT INTO MON MORNING.
WINDS ARE EXPECTED TO STEADILY BACK FROM NNW SUN EVENING TO WRLY BY
EARLY MON AFTERNOON AS SFC HIGH PRESSURE SLIDES FROM THE NRN PLAINS
INTO THE MID MISSISSIPPI VALLEY. THE STEADILY BACKING WINDS WILL
TEND TO SPREAD LES ACCUMULATION AROUND KEEPING MOST AREAS ON THE
LOWER END OF ADVISORY CRITERIA. FAR ERN ALGER AND NRN LUCE WILL BE
THE EXCEPTION WHERE MODELS INDICATE A LONGER PERIOD OF ENHANCED
LOW-LVL CONVERGENCE PARTICULARLY LATE SUN NIGHT INTO MONDAY
WHICH WILL LIKELY PUSH SNOWFALL AMOUNTS ON THE HIGHER END OF
ADVISORY CRITERIA (NEAR 8"). THE VERY DRY COLD ARCTIC AIRMASS ALONG
WITH THE SHORTER FETCH INTO NW UPPER MI WILL MAKE IT LESS FAVORABLE
FOR SIGNIFICANT LES THERE. ADDITIONAL LES WILL BE MORE ON THE ORDER
OF 2 TO LOCALLY 5 INCHES FOR SUN NIGHT INTO MON MORNING SO DO NOT
ANTICIPATE A NEED TO EXTEND LES ADVISORY THERE BEYOND SUNDAY.
HOWEVER...SOME OF THE MESOSCALE MODELS INDICATE THAT LOW-LVL
CONVERGENCE COULD INCREASE AND SOME ENHANCEMENT IS POSSIBLE WITH THE
APPROACH OF THE NEXT CLIPPER SHORTWAVE WHICH SHOULD FOCUS SOME
LOCALLY HEAVIER LES BANDS AND HIGHER ACCUMS BACK OVER THE KEWEENAW
MON AFTERNOON INTO MON EVENING...BUT FOR NOW THIS IS JUST REFLECTED
IN THE FCST GRIDS AND NO HEADLINE IS NEEDED YET.
THE OTHER ISSUE FOR SUNDAY NIGHT INTO MONDAY MORNING WILL BE THE
BITTER COLD ARCTIC AIRMASS SPREADING OVER THE REGION. WITH 8H TEMPS
FROM -22C TO -24C AND WINDS BACKING OFFSHORE TO A MORE WRLY
DIRECTION...THE WESTERN INTERIOR OF THE FCST AREA PARTICULARLY ALONG
THE WI BDR WILL BE UNDER THE GUN FOR ADVISORY CRITERIA WIND CHILLS
OF 25 TO 35 BELOW SUNDAY NIGHT INTO MON MORNING. GIVEN THE FOCUS ON
THE PRESENT LES HEADLINES ELECTED TO HOLD OFF ON WIND CHILL
ADVISORIES FOR NOW...BUT NO DOUBT ONE WILL BE NEEDED FOR A GOOD
PORTION OF THE WESTERN INTERIOR SUN NIGHT INTO MON MORNING.
MON NIGHT-THU...AS MODELS SHOW THE POLAR VORTEX GRADUALLY SHIFTING
FROM HUDSON BAY TO NRN QUEBEC BY TUE EVENING...VERY COLD ARCTIC AIR
WILL DOMINATE THE UPPER GREAT LAKES THROUGH MIDWEEK. WITH 850 MB
TEMPS DROPPING INTO THE -24C TO -29C RANGE...LES WILL PERSIST FOR
LOCATIONS FAVORED BY NW TO WNW FLOW. MODELS IN GOOD AGREEMENT WITH
TIMING OF NEXT CLIPPER SHORTWAVE ACROSS THE AREA MON NIGHT INTO TUE
MORNING. THIS SHORTWAVE WILL REINFORCE ARCTIC AIR WHILE ALSO
SPREADING MID Q-VECT CONV AND DEEPER MOISTURE ACROSS THE REGION.
MODELS INDICATE THIS SHORTWAVE COULD PROVIDE ENHANCEMENT TO LES
WHILE ALSO SHARPENING LAKE-INDUCED TROFFING AND LOW-LVL CONVERGENCE
OVER ERN LAKE SUPERIOR. WHILE THE INFLUX OF COLDER -24 TO -27C 8H
TEMPS BY TUESDAY WILL EVENTUALLY LEAD TO POOR SNOW GROWTH AND
SMALLER SNOWFLAKES...THE WRF-ARW BUFR SNDG FOR GRAND MARAIS MON
NIGHT INTO EARLY TUE SHOWS A SOMEWHAT FAVORABLE SNOW GROWTH PROFILE
WITH THE DGZ INITIALLY INTERSECTING THE BETTER MODEL OMEGA FOCUSED
WITHIN THE CONVECTIVE BOUNDARY LAYER. THIS COULD INITIALLY LEAD TO
HIGHER SLR/S...FLUFFIER SNOW AND GREATER ACCUMULATIONS ESPECIALLY
FOR ERN ALGER AND LUCE COUNTIES. GIVEN THE ABOVE FAVORABLE FACTORS
AND POTENTIAL FOR ENHANCEMENT THERE IS A POTENTIAL FOR HIGH END
ADVISORY LES ACCUMS POSSIBLY PUSHING LES WARNING AMTS MON NIGHT INTO
TUE MORNING FOR ERN ALGER AND LUCE COUNTIES. AFTER TUESDAY...MODELS NOT
INDICATING ANY DISCERNIBLE CLIPPER SHORTWAVES FOR MIDWEEK AS 850 MB
TEMPS GENERALLY REMAIN IN THE -22 TO -26C RANGE. THE COLDER AIRMASS
WILL GENERALLY FAVOR SMALL SNOWFLAKES WITH THE ABSENCE OF
ENHANCEMENT/DEEPER MOISTURE WHICH WILL LIMIT OVERALL ACCUMULATIONS
BUT STILL LEAD TO LOW VISIBILITIES. OUTSIDE OF THE LES...SEVERE WIND
CHILLS CAN BE EXPECTED AT TIMES AS VALUES DROP INTO THE -20 TO -35
RANGE...MAINLY IN THE NIGHTTIME AND MORNING HRS.
MODELS SHOW SIGNS OF TRENDING TOWARD LESS AMPLIFIED PATTERN BY THE
END OF THE WEEK WITH WAA DEVELOPING BY FRI. AS SFC HIGH PRESSURE
SLIDES EAST LATE IN THE WEEK...BOTH THE ECMWF AND GFS DEVELOP AREA
OF LIGHT SNOW IN REGION OF WAA/ISENTROPIC ASCENT AHEAD OF A SHRTWV
MOVING DOWN FM NW ONTARIO. THIS SNOW LOOKS TO SPREAD INTO UPPER MI
LATE FRI OR FRI NIGHT. AS SYSTEM SNOW TAPERS OFF EARLY SAT...LIGHT
LES COULD DEVELOP LATE IN THE DAY AS WINDS SHIFT NORTHERLY BEHIND
FRONTAL PASSAGE.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SUNDAY AFTERNOON)
ISSUED AT 1254 PM EST SAT DEC 28 2013
A COLD FRONT THAT HAS STALLED OVER SOUTHERN LAKE SUPERIOR HAS
ALLOWED WARM MOIST AIR TO SURGE NORTHEAST AND LEAD TO LOW END MVFR
AND HIGH END IFR CONDITIONS AT ALL THREE TAF SITES THIS AFTERNOON.
EXPECT THIS TO CONTINUE THROUGH MUCH OF THE AFTERNOON...BUT THERE
ARE A COUPLE CONCERNS. FIRST...BELIEVE THERE IS SOME -DZ/FZDZ IN
THE KEWEENAW SO HAVE CONTINUED SLIGHTLY LOWER VISIBILITIES AND
-FZDZ IN THE TAF. WILL NEED TO MONITOR LOWER CEILINGS WITH THE
EASTERLY FLOW DEVELOPING OFF LAKE SUPERIOR. AT KSAW...A POCKET OF
DRIER AIR DEVELOPED NEAR LAKE MICHIGAN AND SURGED NORTH.
UNFORTUNATELY...WITH HIGH CLOUDS STREAMING IN AHEAD OF THE NEXT
DISTURBANCE...CAN/T GET A GOOD HANDLE ON THE WESTWARD EXTENT OF
THOSE BREAKS. LOW LEVEL SOUTHWESTERLY WINDS AND LOW CLOUDS AT KIMT
WOULD LEAD TO BELIEVE THE LOW CLOUDS WILL HOLD FOR MUCH OF THE
AFTERNOON.
HEADING INTO THIS EVENING...A LOW IN CENTRAL MINNESOTA WILL SHIFT
EAST ACROSS WISCONSIN TONIGHT AND DRAG AN AREA OF SNOW SOUTHEAST
FROM SOUTHERN MANITOBA AND ACROSS THE AREA. THIS SNOW...COMBINED
WITH LAKE ENHANCEMENT AND GUSTY NORTHEST TO NORTHERLY WINDS WILL
LEAD TO VISIBILITIES FALLING BELOW ALTERNATE LANDING MINS. WOULDN/T
BE SURPRISED IF THERE WERE A FEW PERIODS OF AIRFIELD LANDING MINS
AT KCMX WITH THE STRONGER WINDS AND BETTER SYNOPTIC SNOW. THIS SNOW
WILL TRANSITION TO LAKE EFFECT ON SUNDAY MORNING AS THE LOW
DEPARTS. WOULD EXPECT VISIBILITIES TO COME UP SOME...BUT WITH FINER
FLAKES EXPECTED...HAVE LEFT AT LOW END MVFR OR IFR VALUES.
&&
.MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 419 PM EST SAT DEC 28 2013
WINDS TO STAY LIGHT UNTIL SFC LOW BRINGS TIGHTENING PRESSURE
GRADIENT TO WESTERN LAKE SUPERIOR THIS AFTERNOON. BY LATE
AFTERNOON...WILL SEE FREQUENT GALE FORCE GUSTS OVER WESTERN LAKE
SUPERIOR WITH NE GALES EXPECTED BY THE EVENING. AS THE SFC LOW
PASSES TO THE SE OF THE AREA OVERNIGHT...NORTH WINDS TO GRADUALLY
RELAX. MUCH COLDER AIR ARRIVING TONIGHT WILL PRODUCE HEAVY FREEZING
SPRAY AS WELL. WINDS GO BELOW 25 KNOTS SUNDAY AFTERNOON AND BELOW 20
KNOTS BY MONDAY AFTERNOON. WINDS REMAIN BELOW 20 KNOTS THROUGH THE
REMAINDER OF THE FORECAST.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
LAKE EFFECT SNOW ADVISORY FROM 10 PM THIS EVENING TO 7 PM EST
SUNDAY FOR MIZ004-005-084.
LAKE EFFECT SNOW ADVISORY FROM 1 PM SUNDAY TO 7 AM EST MONDAY
FOR MIZ085.
LAKE EFFECT SNOW ADVISORY UNTIL 7 PM EST /6 PM CST/ SUNDAY FOR
MIZ001>003-009.
LAKE EFFECT SNOW ADVISORY FROM 1 AM SUNDAY TO 1 PM EST MONDAY
FOR MIZ006.
LAKE EFFECT SNOW ADVISORY FROM 7 PM SUNDAY TO 1 PM EST MONDAY
FOR MIZ007.
LAKE SUPERIOR...
HEAVY FREEZING SPRAY WARNING FROM 1 AM SUNDAY TO 1 AM EST
WEDNESDAY FOR LSZ265>267.
GALE WARNING UNTIL 7 AM EST /6 AM CST/ SUNDAY FOR LSZ162-263>266.
HEAVY FREEZING SPRAY WARNING UNTIL 1 AM EST /MIDNIGHT CST/
MONDAY FOR LSZ162-263-264.
HEAVY FREEZING SPRAY WARNING FROM 1 AM SUNDAY TO 6 PM EST MONDAY
FOR LSZ248>251.
HEAVY FREEZING SPRAY WARNING UNTIL 7 PM EST /6 PM CST/ SUNDAY
FOR LSZ240>247.
GALE WARNING UNTIL 5 AM EST /4 AM CST/ SUNDAY FOR LSZ241.
GALE WARNING UNTIL 5 AM EST /4 AM CST/ SUNDAY FOR LSZ240.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...SRF
LONG TERM...VOSS
AVIATION...SRF
MARINE...SRF
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
422 PM EST SAT DEC 28 2013
.SHORT TERM...(THIS EVENING THROUGH SUNDAY)
ISSUED AT 419 PM EST SAT DEC 28 2013
A STALLED FRONTAL BOUNDARY OVER SOUTHERN LAKE SUPERIOR AND NORTHERN
UPPER MICHIGAN HAS LED TO DREARY CONDITIONS FOR MUCH OF UPPER
MICHIGAN TODAY. ON THE PLUS SIDE...TEMPERATURES HAVE BEEN IN THE
LOW TO MID 30S ALONG AND SOUTH OF THE BOUNDARY WHERE THERE HAVE
EVEN BEEN A FEW PEAKS OF SUNSHINE. JUST TO THE NORTH OF THE
BOUNDARY...FAVORABLE EASTERLY FLOW OFF LAKE SUPERIOR HAS LED TO
SOME FZDZ...FOG...AND -SHSN OVER THE KEWEENAW PENINSULA. A SPOTTER
REPORT AROUND 3PM INDICATED A SLIGHT GLAZE IN MOHAWK SHORTLY
AFTER THE VISIBILITY REALLY DROPPED AT KCMX. THINK THAT
FREEZING DRIZZLE WILL REMAIN A THREAT OVER THE NEXT COUPLE OF HOURS
AND EVEN DRIFT SOUTHEAST THROUGH THE EVENING...AS MODELS SHOW A
LACK OF ICE CRYSTALS IN THE CLOUDS BEFORE THE MAIN PRECIPITATION
ARRIVES FROM SOUTHERN CANADA LATE THIS EVENING. ALSO FOR THIS
EVENING...DID ADD SOME PATCHY FOG OVER THE SOUTHEAST PART OF THE
CWA WHERE WINDS WILL BE LIGHT AND THERE HAVE BEEN SOME BREAKS IN
THE CLOUDS.
THE LOW THAT IS CURRENTLY CENTERED IN SOUTH CENTRAL MINNESOTA WILL
CONTINUE EAST TONIGHT AND SUNDAY...BEING CENTERED JUST NORTH OF LAKE
ONTARIO BY 00Z MONDAY. AS THIS LOW SWEEPS EAST...AN AREA OF SNOW
(CURRENTLY IN SOUTHWEST ONTARIO AND ALSO ENTERING NORTHWEST
MINNESOTA) WILL SWEEP ACROSS THE UPPER GREAT LAKES LATE THIS
EVENING THROUGH EARLY SUNDAY MORNING. THE SYNOPTIC SNOW WILL BE
AIDED BY THE RIGHT REAR OF THE 110KT UPPER JET THAT SWEEPS ACROSS
TONIGHT. IN ADDITION...POCKET OF 800-600MB FGEN WILL SLIDE THROUGH
WITH THE 850/700MB TROUGH. THUS...EXPECT A PERIOD OF LIGHT SNOW TO
MOVE ACROSS MUCH OF UPPER MICHIGAN FROM WEST TO EAST. WITH THE BEST
FORCING OVER THE NORTHERN HALF OF THE CWA...EXPECT THE BEST SYNOPTIC
SNOWFALL THERE...WHICH WILL BE AIDED BY LAKE ENHANCEMENT. OVER THE
SOUTHERN HALF...ONLY EXPECT A LIGHT DUSTING TO AN INCH AWAY FROM THE
LAKE SUPERIOR INFLUENCES WITH SNOW RATIOS AROUND NORMAL VALUES OF
13-1.
AS FOR THE LAKE ENHANCEMENT...COLD AIR SURGING IN BEHIND THE LOW
(FALLING FROM RAP ANALYZED VALUES OF 0C FROM WEST-EAST OVER THE
CENTRAL U.P. AT 20Z TO -10 TO -16C AT 12Z SUNDAY AND -23C BY 00Z
MONDAY) WILL LEAD TO LAKE ENHANCEMENT FOR AREAS NEAR LAKE SUPERIOR
AS THE WIND DIRECTIONS BECOME FAVORABLE. THE WINDS WILL BE OUT OF
THE NORTHEAST INITIALLY THIS EVENING OVER WESTERN LAKE
SUPERIOR...BUT AS THE SURFACE/925MB LOW MOVES EAST-NORTHEAST THROUGH
NORTHEAST WISCONSIN AND SOUTH CENTRAL UPPER MICHIGAN TONIGHT...THE
WINDS WILL TRANSITION TO THE NORTH OVERNIGHT...NNW SUNDAY
MORNING...AND THEN NW SUNDAY AFTERNOON. THUS...EXPECT THE INITIAL
ENHANCEMENT TO OCCUR LATE IN THE EVENING OVER THE NE FAVORED
LOCATIONS AND THEN TRANSITION WITH THE WINDS INTO SUNDAY MORNING.
THESE STEADY BACKING WINDS WILL LIKELY BE ONE OF THE LIMITING
FACTORS TO HEAVIER SNOWFALL AMOUNTS. THE SECOND ITEM THAT SHOULD
KEEP SNOWFALL AMOUNTS IN THE LES ADVISORY CATEGORY WILL BE THE SHORT
PERIOD WHEN THE LAKE ENHANCEMENT AND LOW LEVEL TEMPERATURE PROFILE
FALL WITHIN THE DGZ. AT MOST LOCATIONS...IT APPEARS LIKE IT WILL
ONLY OCCUR FOR A 3 TO MAYBE 6HOUR PERIOD. THUS...EVEN THOUGH SNOW
RATIOS WILL QUICKLY RISE TO THE LOWER 20S...THEY WILL QUICKLY FALL
ONCE THE DEEPER MOISTURE DEPARTS AND THE INCREASING COLD AIR MOVES
THE CLOUD OUT OF THE DGZ. FINALLY...GUSTY WINDS MAY LIMIT SNOW
RATIOS FROM GROWING MUCH ABOVE 22/23-1 DURING THE FAVORED
PERIOD...EVEN THOUGH ALL OF THE CLOUD IS WITHIN THE DGZ.
OVERALL...ONLY MADE MINOR TWEAKS TO MUCH OF THE SNOWFALL FORECAST
FOR TONIGHT INTO SUNDAY MORNING...LARGELY WITH HANDLING THE TIMING
OF THE CHANGE OVER TO SNOW FROM NORTHWEST TO SOUTHEAST. THE FAVORED
HIGHER TERRAIN LOCATIONS WILL LIKELY SEE AMOUNTS THROUGH SUNDAY
MORNING IN THE 3-8INCH RANGE...WITH THE GREATEST AMOUNTS OVER THE
HURON MOUNTAINS WITH THE LONGER PERIOD OF FAVORABLE WIND
DIRECTIONS. THAT WOULD BE THE ONLY LOCATIONS WHERE SOME CONCERN OF
NEAR WARNING AMOUNT SNOW WOULD OCCUR...BUT THE SOCIETAL IMPACT WILL
BE LIMITED.
DEEPER MOISTURE FROM THE LOW PULLS OUT QUICKLY FROM WEST TO EAST ON
SUNDAY MORNING AND LEADS TO A TRANSITION TO PURE LAKE EFFECT. WITH
THAT DEEPER MOISTURE DEPARTING...MODELS ARE ONLY SHOWING MOISTURE
AND INVERSION HEIGHTS AROUND 4KFT...BUT WITH LAKE INDUCED
EQUILIBRIUM LEVELS AROUND 5-6KFT...COULD STILL BE SOME STRONGER SNOW
SHOWERS. BUT WITH COLDER AIR CONTINUING TO SURGE IN...MUCH OF THE
CLOUD LAYER WILL MOVE TO THE TOP OF OR ABOVE THE DGZ...WHICH SHOULD
LEAD TO A TRANSITION TO MORE OF COLUMN/PLATES. THEREFORE...WILL
CONTINUE THE IDEA OF LOWERING SNOW RATIOS TO THE HIGH TEENS OR
AROUND 20-1 FROM WEST TO EAST THROUGH THE DAY SUNDAY. THIS SHOULD
LEAD TO LESSER SNOWFALL AMOUNTS IN THE AFTERNOON...WHICH WILL STILL
BE AIDED BY SLOWLY BACKING WINDS TO THE NORTHWEST. OVERALL...HAVE
AFTERNOON AMOUNTS OF 1-2 INCHES IN MOST LOCATIONS...WITH SLIGHTLY
HIGHER VALUES OVER WESTERN ALGER COUNTY. THEREFORE...WILL KEEP LES
ADVISORIES AS IS...ALTHOUGH THE LONG TERM DID MAKE SOME ADJUSTMENTS
TO ALGER TO EXTEND INTO MONDAY. THINK THAT COVERS THE OVERALL IDEA
VERY WELL...SINCE THE NEGATIVES WITH SNOW RATIOS AND BACKING WINDS
SHOULD LIMIT THE POTENTIAL FOR 12HR SNOW AMOUNTS REACHING WARNING
VALUES.
THE COLD AIR SURGING IN WILL LEAD TO FALLING TEMPERATURES STARTING
LATE THIS EVENING OVER THE WEST AND PUSHING ACROSS THE REST OF THE
AREA THROUGH THE NIGHT. OVERNIGHT LOWS FOR TONIGHT AND HIGHS FOR
TOMORROW ARE FAIRLY TRICKY...AS THEY BOTH WILL LIKELY OCCUR DURING
THE TWO HOUR OVERLAP BETWEEN 12-14Z. THUS...TRIED TO FOCUS ON TEMPS
DURING THAT PERIOD TO USE FOR SIMILAR VALUES. WITH THE COLD AIR
CONTINUING TO SURGE IN THROUGH THE DAY ON SUNDAY...EXPECT STEADY OR
SLOWLY FALLING TEMPERATURES THROUGH THE REST OF THE DAY ON
SUNDAY. AFTERNOON VALUES OVER THE WEST WILL BE IN THE LOWER SINGLE
DIGITS ABOVE ZERO AND AROUND 10 DEGREES OVER THE EAST HALF.
FACTORING IN WIND CHILLS...TOMORROW AFTERNOON WILL FEEL ABOUT 50
DEGREES COLDER THAN THIS PAST AFTERNOON.
.LONG TERM...(SUNDAY THROUGH FRIDAY)
ISSUED AT 509 AM EST SAT DEC 28 2013
SAT NIGHT...UPPER LEVEL DIV WITH THE RIGHT ENTRANCE OF THE 130KT
250-300 MB JET THROUGH NRN ONTARIO/WRN QUEBEC AND ASSOCIATED
800-600 MB FGEN WILL RESULT IN STRONG ENOUGH UPWARD MOTION TO
SUPPORT A BAND OF SNOW FROM NRN MN THROUGH NRN UPPER MI.
HOWEVER...PRIOR TO THE ARRIVAL OF THE DEEPER MOISTURE AND COLD AIR
FROM THE NORTH...00Z/06Z NAM FCST SOUNDINGS SUGGEST WITH ONLY
SHALLOW MOISTURE LACKING ICE NUCLEI PRESENT...SOME PATCHY FREEZING
DRIZZLE MAY PERSIST THROUGH AT LEAST 03Z. CONSENSUS QPF AMOUNTS OF
0.10-0.15 WITH SLR VALUES IN THE 10/1 TO 15/1 RANGE WOULD GIVE
SYNOPTIC SNOW AMOUNTS OF 1 TO 2 INCHES...GREATEST NORTH. IN
ADDITION...CYCLONIC NE TO NNE FLOW INTO NRN UPPER MI WILL ALSO BRING
ADDITIONAL LAKE ENHANCED SNOW AMOUNTS. SINCE SLR VALUES ONLY CLIMB
NEAR 20/1 LATE SAT NIGHT WITH THE ARRIVAL OF THE COLDER
AIR...ADDITIONAL ENHANCEMENT AMOUNTS IN THE 1 TO 4 INCH RANGE WOULD
KEEP OVERALL TOTAL GENERALLY IN THE ADVISORY RANGE OF 3 TO 6 INCHES.
IN ADDITION...NRLY WINDS GUSTING TO 25 TO 35 MPH IN OPEN AREAS NEAR
THE LAKE SHORES WILL PRODUCE BLOWING AND DRIFTING SNOW.
SUN...LAKE ENHANCED SNOW WILL TRANSITION TO PURE LES SUN MORNING
AS THE DEEPER MOISTURE AND MID LVL QVECT CONV DEPARTS TO THE EAST.
850 MB TEMPS DROPPING INTO THE -19C TO -22C RANGE BY 18Z AS 850-700
MB MOISTURE STILL LINGERS OVER AREA WILL FAVOR CONTINUED MODERATE TO
HEAVY LES...ESPECIALLY FOR LOCATIONS FAVORED BY NRLY UPSLOPE FLOW.
EXPECT LES RATES TO GRADUALLY DIMINISH IN THE AFTERNOON AS WINDS
BACK AND INVERSION HEIGHTS DROP TO AROUND 5K FT. EXPECT THE GREATEST
TOTAL ACCUMULATIONS FROM IRONWOOD THROUGH THE PORCUPINE MOUNTAINS TO
ROCKLAND IN THE WEST AND FROM HERMAN THROUGH THE HURON MOUNTAINS TO
NEGAUNEE OVER THE NORTH CENTRAL. AS THE WINDS BACK TO THE NNW THE
STRONGER LOW LEVEL CONV AND HEAVIER LES WILL SHIFT TOWARD WRN ALGER
COUNTY IN THE AFTERNOON.
SUN NIGHT...ENHANCED LOW-LEVEL CONVERGENCE FROM DEVELOPING LAND
BREEZES WILL FAVOR ALGER COUNTY INTO NRN SHCOOLCRAFT AND LUCE COUNTIES.
LES ADVISORIES WILL THEN LIKELY BE NEEDED FOR THAT PORTION OF THE NE
CWA WITH ADDITIONAL ACCUMULATIONS IN THE 2 TO 6 INCH RANGE.
OTHERWISE...THE VERY DRY COLD ARCTIC AIRMASS WITH THE SHORTER FETCH
INTO NW UPPER MI WILL BE LESS FAVORABLE FOR SIGNFICANT LES. SINCE
ONLY 1 TO 3 INCHES OF ADDITIONAL SNOWFALL IS EXPECTED...THE LES ADVY
WAS NOT EXTENDED THROUGH THIS PERIOD.
MON-WED...AS THE POLAR VORTEX GRADUALLY SHIFTS FROM HUDSON BAY TO
NRN QUEBEC...VERY COLD ARCTIC AIR WILL DOMINATE THE WRN GREAT LAKES.
WITH 850 MB TEMPS DROPPING INTO THE -23C TO -28C RANGE...LES WILL
PERSIST FOR LOCATIONS FAVORED BY NW TO W FLOW. AS TO BE EXPECTED
MODELS STILL SHOWING DIFFERENCES WITH TIMING OF SHORTWAVES MOVING
THROUGH THE REGION WITH THE ASSOCIATED WIND SHIFTS. THERE MAY BE
PERIODS WHERE THE WINDS ARE LIGHT ENOUGH FOR LAKE INDUCED TROUGHING
TO DOMINATE THE LOW LEVEL FLOW. THERE MAY ALSO BE PERIOD WHEN
CONVERGENT WRLY FLOW DEVELOPS OVER THE WEST WHICH MAY BRING A PERIOD
OF HEAVIER LES INTO THE KEWEENAW. THE COLD AIRMASS WILL ALSO FAVOR
SMALL SNOWFLAKES THAT WILL LIMIT OVERALL ACCUMULATIONS BUT STILL
LEAD TO LOW VISIBILITIES. OUTSIDE OF THE LES...SEVERE WIND CHILLS AT
TIMES ASE VALUES DROP INTO THE -20 TO -35 RANGE.
MODELS SHOW SIGNS OF TRENDING TOWARD LESS AMPLIFIED PATTERN BY THE
END OF THE WEEK WITH WAA DEVELOPING. SFC HIGH PRESSURE OVER THE
REGION SHOULD ENSURE MOSTLY DRY CONDITIONS ON THURSDAY...EXCEPT FOR
SOME LINGERING LES CLOSE TO LAKE SUPERIOR AS WINDS BECOME LIGHT WITH
THE ARCTIC HIGH OVER THE REGION. BOTH THE ECMWF AND GFS DEVELOP AREA
OF LIGHT SNOW IN AREA OF WAA/ISENTROPIC ASCENT AHEAD OF A SHRTWV MOVING
TOWARD NW ONTARIO THAT MAY SPREAD INTO UPPPER MI FRI OR FRI NIGHT.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SUNDAY AFTERNOON)
ISSUED AT 1254 PM EST SAT DEC 28 2013
A COLD FRONT THAT HAS STALLED OVER SOUTHERN LAKE SUPERIOR HAS
ALLOWED WARM MOIST AIR TO SURGE NORTHEAST AND LEAD TO LOW END MVFR
AND HIGH END IFR CONDITIONS AT ALL THREE TAF SITES THIS AFTERNOON.
EXPECT THIS TO CONTINUE THROUGH MUCH OF THE AFTERNOON...BUT THERE
ARE A COUPLE CONCERNS. FIRST...BELIEVE THERE IS SOME -DZ/FZDZ IN
THE KEWEENAW SO HAVE CONTINUED SLIGHTLY LOWER VISIBILITIES AND
-FZDZ IN THE TAF. WILL NEED TO MONITOR LOWER CEILINGS WITH THE
EASTERLY FLOW DEVELOPING OFF LAKE SUPERIOR. AT KSAW...A POCKET OF
DRIER AIR DEVELOPED NEAR LAKE MICHIGAN AND SURGED NORTH.
UNFORTUNATELY...WITH HIGH CLOUDS STREAMING IN AHEAD OF THE NEXT
DISTURBANCE...CAN/T GET A GOOD HANDLE ON THE WESTWARD EXTENT OF
THOSE BREAKS. LOW LEVEL SOUTHWESTERLY WINDS AND LOW CLOUDS AT KIMT
WOULD LEAD TO BELIEVE THE LOW CLOUDS WILL HOLD FOR MUCH OF THE
AFTERNOON.
HEADING INTO THIS EVENING...A LOW IN CENTRAL MINNESOTA WILL SHIFT
EAST ACROSS WISCONSIN TONIGHT AND DRAG AN AREA OF SNOW SOUTHEAST
FROM SOUTHERN MANITOBA AND ACROSS THE AREA. THIS SNOW...COMBINED
WITH LAKE ENHANCEMENT AND GUSTY NORTHEST TO NORTHERLY WINDS WILL
LEAD TO VISIBILITIES FALLING BELOW ALTERNATE LANDING MINS. WOULDN/T
BE SURPRISED IF THERE WERE A FEW PERIODS OF AIRFIELD LANDING MINS
AT KCMX WITH THE STRONGER WINDS AND BETTER SYNOPTIC SNOW. THIS SNOW
WILL TRANSITION TO LAKE EFFECT ON SUNDAY MORNING AS THE LOW
DEPARTS. WOULD EXPECT VISIBILITIES TO COME UP SOME...BUT WITH FINER
FLAKES EXPECTED...HAVE LEFT AT LOW END MVFR OR IFR VALUES.
&&
.MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 419 PM EST SAT DEC 28 2013
WINDS TO STAY LIGHT UNTIL SFC LOW BRINGS TIGHTENING PRESSURE
GRADIENT TO WESTERN LAKE SUPERIOR THIS AFTERNOON. BY LATE
AFTERNOON...WILL SEE FREQUENT GALE FORCE GUSTS OVER WESTERN LAKE
SUPERIOR WITH NE GALES EXPECTED BY THE EVENING. AS THE SFC LOW
PASSES TO THE SE OF THE AREA OVERNIGHT...NORTH WINDS TO GRADUALLY
RELAX. MUCH COLDER AIR ARRIVING TONIGHT WILL PRODUCE HEAVY FREEZING
SPRAY AS WELL. WINDS GO BELOW 25 KNOTS SUNDAY AFTERNOON AND BELOW 20
KNOTS BY MONDAY AFTERNOON. WINDS REMAIN BELOW 20 KNOTS THROUGH THE
REMAINDER OF THE FORECAST.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
LAKE EFFECT SNOW ADVISORY FROM 10 PM THIS EVENING TO 7 PM EST
SUNDAY FOR MIZ004-005-084.
LAKE EFFECT SNOW ADVISORY FROM 1 PM SUNDAY TO 7 AM EST MONDAY
FOR MIZ085.
LAKE EFFECT SNOW ADVISORY UNTIL 7 PM EST /6 PM CST/ SUNDAY FOR
MIZ001>003-009.
LAKE EFFECT SNOW ADVISORY FROM 1 AM SUNDAY TO 1 PM EST MONDAY
FOR MIZ006.
LAKE EFFECT SNOW ADVISORY FROM 7 PM SUNDAY TO 1 PM EST MONDAY
FOR MIZ007.
LAKE SUPERIOR...
HEAVY FREEZING SPRAY WARNING FROM 1 AM SUNDAY TO 1 AM EST
WEDNESDAY FOR LSZ265>267.
GALE WARNING UNTIL 7 AM EST /6 AM CST/ SUNDAY FOR LSZ162-263>266.
HEAVY FREEZING SPRAY WARNING UNTIL 1 AM EST /MIDNIGHT CST/
MONDAY FOR LSZ162-263-264.
HEAVY FREEZING SPRAY WARNING FROM 1 AM SUNDAY TO 6 PM EST MONDAY
FOR LSZ248>251.
HEAVY FREEZING SPRAY WARNING UNTIL 7 PM EST /6 PM CST/ SUNDAY
FOR LSZ240>247.
GALE WARNING UNTIL 5 AM EST /4 AM CST/ SUNDAY FOR LSZ241.
GALE WARNING UNTIL 5 AM EST /4 AM CST/ SUNDAY FOR LSZ240.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...SRF
LONG TERM...JLB
AVIATION...SRF
MARINE...SRF
AREA FORECAST DISCUSSION
NWS HASTINGS NE
337 PM CST SAT DEC 28 2013
.SHORT TERM...(THIS EVENING THROUGH SUNDAY)
ISSUED AT 337 PM CST SAT DEC 28 2013
...A BRIEF BUT POTENT BLAST OF ARCTIC AIR AS TEMPS PLUNGE FROM
TODAY/S NEAR RECORD WARMTH...
ALOFT: PROGRESSIVE NW REMAINS IN PLACE. AN EMBEDDED POSITIVE-TILT
TROF WAS OVER THE NRN ROCKIES. THIS TROF WILL MOVE THRU HERE
TOMORROW...WITH NW FLOW TO FOLLOW.
SURFACE: LOW PRES HAS BEEN MIGRATING E ALONG AN ARCTIC COLD
FRONT...OUT OF THE DAKOTAS FROM THIS MORNING AND WAS OVER SWRN MN
AT 20Z. THE FRONT WAS SURGING S IN ITS WAKE AND IR SATELLITE
IMAGERY SUGGESTS THAT IT/S THRU THE SANDHILLS AND EXTENDS FROM
ALBION-LOUP CITY-LEXINGTON AT 20Z. THE FRONT SHOULD BE THRU THE
FCST AREA IN 6 HRS OR LESS...EXITING INTO CNTRL KS BY 9PM. STRONG
ARCTIC HIGH PRES BUILDS IN TONIGHT AS IT SLIDES INTO THE NRN
PLAINS. IT WILL WEAKEN TOMORROW AS IT CONTINUES DOWN THE MO RIVER
VALLEY.
UPDATED ADVISORY/HAZARDOUS WX OUTLOOK HAVE POSTED. GOSPER/DAWSON/
PHELPS COUNTIES ARE NOW INCLUDED. THE END TIME HAS ALSO BEEN MOVED
UP TO 3 AM...BUT ADVISORY COULD END UP BEING TERMINATED AS EARLY
AS 12 AM.
REST OF THIS AFTERNOON: WE PUT THE FINISHING TOUCHES ON ANOTHER
VERY NICE DAY FOR LATE DEC WITH NEAR-RECORD MUCH ABOVE NORMAL
WARMTH.
A CHECK OF GRI ASOS AT 335 PM VIA MODEM SHOWS A HIGH OF 62F. THE
FRONT HAS MOVED THRU AND THE TEMP IS DOWN TO 59F. CAME WITHIN 2F
OF TYING THE RECORD HIGH /64 IN 2002/.
WE HAVE BEEN WATCHING IMPRESSIVE PRES GRADIENT OVER ND/SD/MT/WY
TODAY WITH EQUALLY IMPRESSIVE WINDS. PEAK GUSTS OF 45-52 KTS HAVE
BEEN COMMON. THERE IS A CORE OF 40-55 KT WINDS AT 850 MB
COINCIDENT WITH THESE WINDS. THE RAPID CITY 88D CONFIRMS ITS
PRESENCE.
EXPECT DOWNWARD TRANSFER IN VERY STEEP LAPSE RATES/COLD AIR
ADVECTION AS THIS JET CORE DROPS INTO THE FCST AREA.
THE STRONGEST WINDS WILL OCCUR IN THE 6-8 HRS IMMEDIATELY
FOLLOWING PASSAGE OF THE COLD FRONT /IE BEFORE MIDNIGHT/.
VALENTINE HAD A PEAK WIND OF 45 KTS AT 218 PM.
THE WINDIEST LOCATIONS WILL BE ALONG AND N OF HWY 92. RAP TIME-
HEIGHT CROSS SECTIONS SHOW 45 KTS DOWN TO 1K FT WITH A CORE OF 50
KTS DOWN TO 1800 FT FROM 9PM-12AM. 18Z NAM HAS 52 KTS BUT ONLY AS
LOW AS 2K FT 6PM-9PM. BOTTOM LINE...WOULD NOT BE SURPRISED TO SEE
G50-55 MPH IN THESE AREAS THIS EVE.
15Z SREF PROBABILITIES FOR MEAN WINDS 30 MPH OR GREATER ARE
HIGHEST OVER CNTRL NEB N INTO THE SANDHILLS 6PM-11PM. THIS IS
WHERE THE ADVISORY HAS THE BEST CHANCE OF VERIFYING.
TONIGHT: WINDY AND TURNING MUCH COLDER. BECOMING MOSTLY CLOUDY AS
THE 900-850 MB LAYER COOLS TO SATURATION. EXTENSIVE MID-HIGH
CLOUDS WILL ALSO INVADE. LOW TEMPS ROUGHLY 8F COLDER THAN NORMAL.
TOMORROW: DECREASING CLOUDS AND WINDS. TEMPS MUCH COLDER THAN
NORMAL /BY 15-20F/.
.LONG TERM...(SUNDAY NIGHT THROUGH SATURDAY)
ISSUED AT 332 PM CST SAT DEC 28 2013
A 1035MB SURFACE HIGH PRESSURE SYSTEM WILL BUILD SOUTH ALONG THE
MISSOURI RIVER SUNDAY EVENING...AND EXPECT TEMPERATURES WILL DROP
OFF RATHER QUICKLY FOR THE FIRST PART OF THE NIGHT. AS THE SFC
RIDGE AXIS WEAKENS AND SHIFTS EASTWARD SUNDAY NIGHT...RETURN FLOW
SETS UP AND THE AIRMASS BEGINS TO MODERATE AND TEMPERATURES SHOULD
TREND UP HEADING INTO MONDAY MORNING.
THE UPPER TROUGH AXIS WILL TRANSLATE EAST/NORTHEASTWARD FOR THE
FIRST PART OF THE WEEK...WHICH ALLOWS FOR A REBOUND IN
TEMPERATURES FOR OUR AREA AS HEIGHTS RISE BEHIND THE SYSTEM. THIS
BEING SAID IT IS IMPORTANT TO NOTE THAT THE COLD AIR IS NOT THAT
FAR AWAY AND IF THE BAROCLINIC ZONE SHIFTS FARTHER SOUTH AND
WEST...IT WILL BE ACROSS US AND TEMPS WILL BE COLDER. THE BIGGEST
CHANGE IN THE FORECAST COMES IN THE TUESDAY TIME FRAME AS SEVERAL
OF THE LATEST OPERATIONAL MODELS NO LONGER BACK A COLD FRONT AS
FAR SOUTH INTO SC NEBRASKA AS PREVIOUS RUNS. MODELS ARE IN PRETTY
GOOD AGREEMENT THAT THE COLD AIR AND STRATUS WILL BE ORIENTED
ACROSS SOUTH DAKOTA/NORTHERN IOWA AND PERHAPS FAR NORTHERN
NEBRASKA THROUGH THE DAY...ALTHOUGH A COLD FRONT DOES ADVANCE
SOUTH IN THE AFTN. HAVE RAISED TEMPERATURES FOR TUESDAY...BUT WILL
NEED TO MONITOR THERMAL AND CLOUD FIELDS CLOSELY AS THE 12Z ECMWF
REMAINS COLDER THAN GFS/GEM/NAM IN THIS TIME FRAME.
A COLD FRONT PUSHES SOUTH TUESDAY/NEW YEARS EVE NIGHT AND MODELS
ARE NOT OVERLY ROBUST IN GENERATING PCPN WITH THIS BUT DID
MAINTAIN SOME VERY LOW POPS FOR LIGHT SNOW ACROSS OUR NORTHEAST
ZONES. LIGHT WINTRY PCPN IS POSSIBLE ON WEDNESDAY/NEW YEARS DAY AS
A 120KT JET NOSES SOUTH ALONG THE ROCKIES/HIGH PLAINS REGION AND
DEEPENS A TROUGH ACROSS THE PLAINS AND UPPER MIDWEST. COLDER AIR
ADVECTS SOUTH AND A BAND OF FRONTOGENETIC SNOWFALL IS POSSIBLE
INTO WEDNESDAY NIGHT.
THURSDAY WILL BE THE TRANSITION DAY BETWEEN THE COLD AIR AT THE
MIDDLE OF THE WEEK AND A WARMING TREND FOR THE END OF THE WEEK.
THE UPPER TROUGH AND COLD AIR ONCE AGAIN SLIDE EAST THURSDAY WITH
HEIGHTS RISING/MODERATING TEMPS IN ITS WAKE. FRIDAY IS SHAPING UP
TO BE MILD AGAIN WITH ABOVE NORMAL TEMPS IN SUBTLE RIDGING ALOFT.
SATURDAY TEMPS WILL BE DEPENDENT ON COLD FRONTAL TIMING WITH THE
GFS QUICKER WITH THE FRONT PASSAGE THAN THE ECMWF...AND GIVEN
MODEL DIFFERENCES DID NOT DEVIATE MUCH FROM INIT FOR DAY 7.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SUNDAY AFTERNOON)
ISSUED AT 1207 PM CST SAT DEC 28 2013
THIS AFTERNOON: VFR WITH JUST A FEW SHREDS OF CIRRUS ON THE NW
HORIZON. SW WINDS WILL HOLD STEADY AROUND 15 KTS AND THEN SHIFT TO
W AS A PRE-FRONTAL TROF MOVES THRU. THE ARCTIC FRONT SHOULD ARRIVE
AROUND 22Z WITH A WSHFT TO NW. WINDS WILL GUST 25-30 KTS.
CONFIDENCE: HIGH
TONIGHT: NW WINDS WILL BECOME NNW AND GUST 35-40 KTS. THERE IS
POTENTIAL FOR A ONE-TIME TO NEAR G43 KTS. SUSTAINED WINDS WILL
AVERAGE 25-30 KTS PRIOR TO MIDNIGHT...THEN DROP TO 20-25 KTS. MVFR
CIGS SHOULD DEVELOP WITHIN AN HOUR OR TWO OF 00Z. CONFIDENCE: HIGH
SUN THRU 18Z: MVFR CIGS SHOULD DECREASE TO SCT. NNW WINDS CONT TO
DIMINISH. CONFIDENCE: HIGH
&&
.GID WATCHES/WARNINGS/ADVISORIES...
NE...WIND ADVISORY UNTIL 3 AM CST SUNDAY FOR NEZ039>041-046>049-
060>064-072>077.
KS...NONE.
&&
$$
SHORT TERM...HALBLAUB 337
LONG TERM...FAY
AVIATION...HALBLAUB
AREA FORECAST DISCUSSION
NWS NORTH PLATTE NE
333 PM CST SAT DEC 28 2013
.SHORT TERM...(THIS EVENING THROUGH SUNDAY)
ISSUED AT 331 PM CST SAT DEC 28 2013
THE WIND ADVISORY LOOKS GOOD FOR MOST OF WESTERN AND NORTH CENTRAL
NEBRASKA TONIGHT. HAVE EXPANDED TO INCLUDE A BIT MORE OF SOUTHWEST
NEBRASKA...WHERE BOTH THE 18Z NAM AND RAP MODELS INDICATE A CORE OF
STRONGER WINDS JUST OFF THE SURFACE MOVING ACROSS THIS EVENING.
WINDS WILL DIMINISH ACROSS THE ENTIRE AREA LATE TONIGHT...BUT REMAIN
STRONG ENOUGH THAT WHEN COMBINED WITH TEMPERATURES NEAR OR JUST
BELOW ZERO ACROSS NORTHERN NEBRASKA...WIND CHILLS WILL REACH
ADVISORY CRITERIA. SO...HAVE ISSUED A WIND CHILL ADVISORY LATE
TONIGHT INTO SUNDAY MORNING FOR NORTHERN NEBRASKA.
STILL SOME CONCERN FOR A BIT OF FREEZING DRIZZLE ACROSS EASTERN
PORTIONS OF NORTH CENTRAL NEBRASKA THROUGH MID EVENING. BUFKIT
SOUNDING DATA JUST EAST OF THE ONEILL AREA SHOWS THE POTENTIAL UNTIL
MID EVENING...WHEN THE SATURATED LOWER LAYER DROPS QUICKLY BELOW
-10C. OTHERWISE THERE IS SOME POTENTIAL FOR A FEW SNOW SHOWERS OR
FLURRIES ELSEWHERE. HRRR MODEL HAS BEEN KEYING ON FLURRY POTENTIAL
ACROSS SOUTHWEST NEBRASKA IN AN AREA OF ENHANCED MID LEVEL
FRONTOGENESIS AND QG FORCING.
HIGH PRESSURE QUICKLY BUILDS INTO THE AREA SUNDAY...WITH WINDS
NEARLY CALM BY AFTERNOON. IT WILL BE COLD THOUGH WITH ARCTIC AIR IN
PLACE.
.LONG TERM...(SUNDAY NIGHT THROUGH SATURDAY)
ISSUED AT 331 PM CST SAT DEC 28 2013
A PROGRESSIVE PATTERN CONTINUES IN THE NORTHWEST FLOW ACROSS THE
PLAINS THROUGH MOST OF NEXT WEEK.
THE NEXT STORM SYSTEM FROM THE CANADIAN ROCKIES COMES THROUGH
WESTERN NEBRASKA TUESDAY. THERE IS SOME ISENTROPIC LIFT INDICATED IN
THE 290-300K LAYER...BUT MOISTURE IS LACKING EVERYWHERE EXCEPT THE
AREA NORTH AND WEST OF ONEILL.
ANOTHER PULSE IS ON THE WAY FOR TUESDAY NIGHT THROUGH WEDNESDAY.
THAT ONE ALSO SHOWS ISENTROPIC LIFT IN THE 290-300K LAYER WITH SOME
FRONTOGENETIC ENHANCEMENT IN CENTRAL AND NORTH CENTRAL NEBRASKA.
THOUGH MOISTURE IS A LITTLE BETTER...IT IS STILL FAIRLY DRY IN THE
LOWER LAYERS. ALSO...THERE ARE SIGNIFICANT DIFFERENCES IN THE
LOCATIONS INDICATED IN THE THREE MEDIUM/LONG RANGE MODELS (THE
ECMWF...GEMNH AND US GFS)...SO WE WILL KEEP THE PROBABILITY LOW FOR
NOW.
ANOTHER SYSTEM IS EXPECTED TO DEVELOP IN COLORADO FRIDAY OR
SATURDAY...BUT THE UNCERTAINTY WITH THAT ONE IS HIGH.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SUNDAY AFTERNOON)
ISSUED AT 1228 PM CST SAT DEC 28 2013
STRONG ARCTIC COLD FRONT MOVING SOUTHEAST ACROSS THE AREA THIS
AFTERNOON. DETERIORATING CONDITIONS EXPECTED ACROSS NORTHERN NEBRASKA
WITH POSSIBLE MVFR CEILINGS AND PATCHY FREEZING DRIZZLE. OTHERWISE
GUSTY WINDS WITH NORTHWEST WINDS 25 TO 35 KTS. FARTHER SOUTH
ACROSS SOUTHWEST NEBRASKA...WINDS WILL INCREASE TO 15 TO 30 KTS.
AT THIS TIME ANY FREEZING DRIZZLE AND LOWER CEILINGS SHOULD REMAIN
NORTH OF SOUTHWEST NEBRASKA.
&&
.LBF WATCHES/WARNINGS/ADVISORIES...
WIND ADVISORY UNTIL MIDNIGHT CST /11 PM MST/ TONIGHT FOR NEZ005-
006-008-009-022>026-035>037-056-057-059-071-094.
WIND CHILL ADVISORY FROM 3 AM CST /2 AM MST/ TO 9 AM CST /8 AM
MST/ SUNDAY FOR NEZ004>010-023>029-094.
WIND ADVISORY UNTIL 3 AM CST SUNDAY FOR NEZ007-010-027>029-038.
&&
$$
SHORT TERM...TAYLOR
LONG TERM...SPRINGER
AVIATION...TAYLOR
AREA FORECAST DISCUSSION
NWS HASTINGS NE
332 PM CST SAT DEC 28 2013
.SHORT TERM...(THIS EVENING THROUGH SUNDAY)
ISSUED AT 332 PM CST SAT DEC 28 2013
...A BRIEF BUT POTENT BLAST OF ARCTIC AIR AS TEMPS PLUNGE FROM
TODAY/S NEAR RECORD WARMTH...
ALOFT: PROGRESSIVE NW REMAINS IN PLACE. AN EMBEDDED POSITIVE-TILT
TROF WAS OVER THE NRN ROCKIES. THIS TROF WILL MOVE THRU HERE
TOMORROW...WITH NW FLOW TO FOLLOW.
SURFACE: LOW PRES HAS BEEN MIGRATING E ALONG AN ARCTIC COLD
FRONT...OUT OF THE DAKOTAS FROM THIS MORNING AND WAS OVER SWRN MN
AT 20Z. THE FRONT WAS SURGING S IN ITS WAKE AND IR SATELLITE
IMAGERY SUGGESTS THAT IT/S THRU THE SANDHILLS AND EXTENDS FROM
ALBION-LOUP CITY-LEXINGTON AT 20Z. THE FRONT SHOULD BE THRU THE
FCST AREA IN 6 HRS OR LESS...EXITING INTO CNTRL KS BY 9PM. STRONG
ARCTIC HIGH PRES BUILDS IN TONIGHT AS IT SLIDES INTO THE NRN
PLAINS. IT WILL WEAKEN TOMORROW AS IT CONTINUES DOWN THE MO RIVER
VALLEY.
UPDATED ADVISORY/HAZARDOUS WX OUTLOOK HAVE POSTED. GOSPER/DAWSON/
PHELPS COUNTIES ARE NOW INCLUDED. THE END TIME HAS ALSO BEEN MOVED
UP TO 3 AM...BUT ADVISORY COULD END UP BEING TERMINATED AS EARLY
AS 12 AM.
REST OF THIS AFTERNOON: WE PUT THE FINISHING TOUCHES ON ANOTHER
VERY NICE DAY FOR LATE DEC WITH NEAR-RECORD MUCH ABOVE NORMAL
WARMTH.
WE HAVE BEEN WATCHING IMPRESSIVE PRES GRADIENT OVER ND/SD/MT/WY
TODAY WITH EQUALLY IMPRESSIVE WINDS. PEAK GUSTS OF 45-52 KTS HAVE
BEEN COMMON. THERE IS A CORE OF 40-55 KT WINDS AT 850 MB
COINCIDENT WITH THESE WINDS. THE RAPID CITY 88D CONFIRMS ITS
PRESENCE.
EXPECT DOWNWARD TRANSFER IN VERY STEEP LAPSE RATES/COLD AIR
ADVECTION AS THIS JET CORE DROPS INTO THE FCST AREA.
THE STRONGEST WINDS WILL OCCUR IN THE 6-8 HRS IMMEDIATELY
FOLLOWING PASSAGE OF THE COLD FRONT /IE BEFORE MIDNIGHT/.
VALENTINE HAD A PEAK WIND OF 45 KTS AT 218 PM.
THE WINDIEST LOCATIONS WILL BE ALONG AND N OF HWY 92. RAP TIME-
HEIGHT CROSS SECTIONS SHOW 45 KTS DOWN TO 1K FT WITH A CORE OF 50
KTS DOWN TO 1800 FT FROM 9PM-12AM. 18Z NAM HAS 52 KTS BUT ONLY AS
LOW AS 2K FT 6PM-9PM. BOTTOM LINE...WOULD NOT BE SURPRISED TO SEE
G50-55 MPH IN THESE AREAS THIS EVE.
15Z SREF PROBABILITIES FOR MEAN WINDS 30 MPH OR GREATER ARE
HIGHEST OVER CNTRL NEB N INTO THE SANDHILLS 6PM-11PM. THIS IS
WHERE THE ADVISORY HAS THE BEST CHANCE OF VERIFYING.
TONIGHT: WINDY AND TURNING MUCH COLDER. BECOMING MOSTLY CLOUDY AS
THE 900-850 MB LAYER COOLS TO SATURATION. EXTENSIVE MID-HIGH
CLOUDS WILL ALSO INVADE. LOW TEMPS ROUGHLY 8F COLDER THAN NORMAL.
TOMORROW: DECREASING CLOUDS AND WINDS. TEMPS MUCH COLDER THAN
NORMAL /BY 15-20F/.
.LONG TERM...(SUNDAY NIGHT THROUGH SATURDAY)
ISSUED AT 332 PM CST SAT DEC 28 2013
A 1035MB SURFACE HIGH PRESSURE SYSTEM WILL BUILD SOUTH ALONG THE
MISSOURI RIVER SUNDAY EVENING...AND EXPECT TEMPERATURES WILL DROP
OFF RATHER QUICKLY FOR THE FIRST PART OF THE NIGHT. AS THE SFC
RIDGE AXIS WEAKENS AND SHIFTS EASTWARD SUNDAY NIGHT...RETURN FLOW
SETS UP AND THE AIRMASS BEGINS TO MODERATE AND TEMPERATURES SHOULD
TREND UP HEADING INTO MONDAY MORNING.
THE UPPER TROUGH AXIS WILL TRANSLATE EAST/NORTHEASTWARD FOR THE
FIRST PART OF THE WEEK...WHICH ALLOWS FOR A REBOUND IN
TEMPERATURES FOR OUR AREA AS HEIGHTS RISE BEHIND THE SYSTEM. THIS
BEING SAID IT IS IMPORTANT TO NOTE THAT THE COLD AIR IS NOT THAT
FAR AWAY AND IF THE BAROCLINIC ZONE SHIFTS FARTHER SOUTH AND
WEST...IT WILL BE ACROSS US AND TEMPS WILL BE COLDER. THE BIGGEST
CHANGE IN THE FORECAST COMES IN THE TUESDAY TIME FRAME AS SEVERAL
OF THE LATEST OPERATIONAL MODELS NO LONGER BACK A COLD FRONT AS
FAR SOUTH INTO SC NEBRASKA AS PREVIOUS RUNS. MODELS ARE IN PRETTY
GOOD AGREEMENT THAT THE COLD AIR AND STRATUS WILL BE ORIENTED
ACROSS SOUTH DAKOTA/NORTHERN IOWA AND PERHAPS FAR NORTHERN
NEBRASKA THROUGH THE DAY...ALTHOUGH A COLD FRONT DOES ADVANCE
SOUTH IN THE AFTN. HAVE RAISED TEMPERATURES FOR TUESDAY...BUT WILL
NEED TO MONITOR THERMAL AND CLOUD FIELDS CLOSELY AS THE 12Z ECMWF
REMAINS COLDER THAN GFS/GEM/NAM IN THIS TIME FRAME.
A COLD FRONT PUSHES SOUTH TUESDAY/NEW YEARS EVE NIGHT AND MODELS
ARE NOT OVERLY ROBUST IN GENERATING PCPN WITH THIS BUT DID
MAINTAIN SOME VERY LOW POPS FOR LIGHT SNOW ACROSS OUR NORTHEAST
ZONES. LIGHT WINTRY PCPN IS POSSIBLE ON WEDNESDAY/NEW YEARS DAY AS
A 120KT JET NOSES SOUTH ALONG THE ROCKIES/HIGH PLAINS REGION AND
DEEPENS A TROUGH ACROSS THE PLAINS AND UPPER MIDWEST. COLDER AIR
ADVECTS SOUTH AND A BAND OF FRONTOGENETIC SNOWFALL IS POSSIBLE
INTO WEDNESDAY NIGHT.
THURSDAY WILL BE THE TRANSITION DAY BETWEEN THE COLD AIR AT THE
MIDDLE OF THE WEEK AND A WARMING TREND FOR THE END OF THE WEEK.
THE UPPER TROUGH AND COLD AIR ONCE AGAIN SLIDE EAST THURSDAY WITH
HEIGHTS RISING/MODERATING TEMPS IN ITS WAKE. FRIDAY IS SHAPING UP
TO BE MILD AGAIN WITH ABOVE NORMAL TEMPS IN SUBTLE RIDGING ALOFT.
SATURDAY TEMPS WILL BE DEPENDENT ON COLD FRONTAL TIMING WITH THE
GFS QUICKER WITH THE FRONT PASSAGE THAN THE ECMWF...AND GIVEN
MODEL DIFFERENCES DID NOT DEVIATE MUCH FROM INIT FOR DAY 7.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SUNDAY AFTERNOON)
ISSUED AT 1207 PM CST SAT DEC 28 2013
THIS AFTERNOON: VFR WITH JUST A FEW SHREDS OF CIRRUS ON THE NW
HORIZON. SW WINDS WILL HOLD STEADY AROUND 15 KTS AND THEN SHIFT TO
W AS A PRE-FRONTAL TROF MOVES THRU. THE ARCTIC FRONT SHOULD ARRIVE
AROUND 22Z WITH A WSHFT TO NW. WINDS WILL GUST 25-30 KTS.
CONFIDENCE: HIGH
TONIGHT: NW WINDS WILL BECOME NNW AND GUST 35-40 KTS. THERE IS
POTENTIAL FOR A ONE-TIME TO NEAR G43 KTS. SUSTAINED WINDS WILL
AVERAGE 25-30 KTS PRIOR TO MIDNIGHT...THEN DROP TO 20-25 KTS. MVFR
CIGS SHOULD DEVELOP WITHIN AN HOUR OR TWO OF 00Z. CONFIDENCE: HIGH
SUN THRU 18Z: MVFR CIGS SHOULD DECREASE TO SCT. NNW WINDS CONT TO
DIMINISH. CONFIDENCE: HIGH
&&
.GID WATCHES/WARNINGS/ADVISORIES...
NE...WIND ADVISORY UNTIL 3 AM CST SUNDAY FOR NEZ039>041-046>049-
060>064-072>077.
KS...NONE.
&&
$$
SHORT TERM...HALBLAUB
LONG TERM...FAY
AVIATION...HALBLAUB
AREA FORECAST DISCUSSION
NWS NORTH PLATTE NE
1232 PM CST SAT DEC 28 2013
.UPDATE...
ISSUED AT 1212 PM CST SAT DEC 28 2013
HAVE EXPANDED THE WIND ADVISORY TO INCLUDE THE WESTERN SANDHILLS
INTO THE SOUTHERN PANHANDLE. VERY STRONG PRESSURE RISES WILL SLIDE
ACROSS THE AREA THIS AFTERNOON...WITH BOTH THE RAP AND NAM MODELS
INDICATING 500 METER WIND SPEEDS APPROACHING 40 KTS. IT IS
POSSIBLE THAT NEAR HIGH WIND WARNING WIND SPEEDS COULD BE REACHED
ACROSS NORTH CENTRAL NEBRASKA FROM MID AFTERNOON THROUGH EARLY
EVENING...AND WILL MONITOR THIS CLOSELY. HAVE SEEN 65 MPH WIND
GUSTS LATE THIS MORNING ACROSS NORTHWEST SOUTH DAKOTA. STILL
COULD SEE SOME PATCHY FREEZING DRIZZLE...AS SOUNDINGS CONTINUE TO
INDICATE A NARROW WINDOW FOR THIS POTENTIAL ACROSS NORTHERN
NEBRASKA.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 333 AM CST SAT DEC 28 2013
MODELS IN FAIR AGREEMENT WITH TIMING OF FRONT AND HAVE USED A
BLEND. WINDS AND PRECIPITATION TYPE WILL BE NEAR TERM CONCERNS.
SURFACE LOW CENTERED NEAR CANADIAN EASTERN MONTANA BORDER WITH
SURFACE TROUGH INTO THE WESTERN NEBRASKA PANHANDLE INTO NORTHEAST
COLORADO. COLD FRONT ALONG MONTANA CANADIAN BORDER. 3HR PRESSURE
CHANGES HAVE A STRONG 10MB RISE OVER NORTH CENTRAL MONTANA WITH
-3MB PRESSURE FALLS INTO THE DAKOTAS. LEADING EDGE OF COLD FRONT
TO DROP THROUGH MOST OF THE CWA BY 18Z TODAY. HIGH TEMPERATURES
EARLY WITH RAPIDLY FALLING TEMPERATURES THROUGH THE AFTERNOON.
HAVE TRENDED LOWER WITH HIGHS WITH UPPER 30S NORTHWEST AND AROUND
50 TO THE SOUTHWEST. THESE MAY HAVE TO BE TRENDED DOWNWARD. TIGHT
PRESSURE GRADIENT AND WIND ADVISORY WINDS DEVELOP 18Z THROUGH
MIDNIGHT. WILL CONTINUE GOING WIND ADVISORY. THIS AFTERNOON TIME
HEIGHTS OVER NORTHERN NEBRASKA HAVE INCREASING LOW LEVEL RH WITH
WEAK LIFT AND DRY LAYER 800MB AND ABOVE. BUFR SOUNDINGS
INDICATIVE OF FREEZING DRIZZLE. HAVE CUT BACK ON START OF
PRECIPITATION BUT CARRIED LIGHT FREEZING DRIZZLE OR LIGHT SNOW
SHOWERS. AFTER 00Z CARRIED SNOW SHOWERS. MINIMAL CHANCES
GENERALLY NORTH OF HIGHWAY 2. WITH PARTIAL CLEARING TONIGHT
TEMPERATURES TO DROP SIGNIFICANTLY WITH COLDER AIR OVER NORTHWEST
WHERE THERE IS STILL SOME SNOW COVER AS 1040MB HIGH NOSES INTO
NORTHERN NEBRASKA. STRONG NORTHWEST WINDS AND SOME CLOUD COVER
MAY KEEP TEMPERATURES FROM REACHING THEIR FULL POTENTIAL.
.LONG TERM...(SUNDAY THROUGH FRIDAY)
ISSUED AT 333 AM CST SAT DEC 28 2013
SUNDAY MORNING THE ARCTIC HIGH PRESSURE WILL STRETCH FROM THE
NORTHERN PLAINS TO THE CENTRAL PLAINS. RESULTING IN MUCH COOLER
AIR ACROSS THE REGION. LATE IN THE DAY...AS THE HIGH PUSHES
EAST...850 MB TEMPS ON THE INCREASE. THIS WILL ALLOW FOR FAR SW
TO REBOUND CLOSE TO 30...OTHERWISE TEENS ACROSS N CENTRAL WITH
20S ELSEWHERE. THE HIGH WILL ALSO BRING DRY CONDITIONS. WAA
CONTINUES SUNDAY NIGHT AS THE HIGH CONTINUES TO DRIFT SE.
OVERNIGHT TEMPS STILL CHILLY...SINGLE DIGITS AND TEENS AS MODELS
IN GOOD AGREEMENT WITH THE BL STILL DECOUPLING.
EARLY NEXT WEEK THE MAIN FLOW IS NW ACROSS THE HIGH PLAINS. A
COUPLE OF CLIPPERS ARE EXPECTED TO QUICKLY MOVE ACROSS THE AREA.
CLOUDS ARE EXPECTED WITH EACH WAVE...HOWEVER UNSURE ON PRECIP.
MODELS INDICATE TOP DOWN SATURATION AND A SLOWLY INCREASING LOW
LEVEL MOISTURE FIELD WITH EACH PASSING WAVE. PRECIPITABLE WATERS
MONDAY MORNING START OUT NEAR THE 50 PERCENTILE /0.30 INCHES/ AND
INCREASE TO ABOVE THE 75 PERCENTILE /AROUND 0.45 INCHES/ BY
TUESDAY AFTERNOON/EVENING. WHILE LIFT IS LIMITED OVER THE CWA
WITH THE BETTER LIFT TO THE NORTH ACROSS S DAKOTA...SOME MODEL
AGREEMENT TUES/TUES NIGHT FOR GETTING SOME SNOWFALL TO REACH THE
GROUND. ONE NOTE IS THE EC IS A LITTLE SLOWER...AND AN OUTLIER AT
THIS TIME...KEEPING THINGS DRY UNTIL WEDNESDAY.
TO START THE NEW YEAR...WED INTO FRIDAY...A SEASONAL TO
SEASONALLY WARM PERIOD AND DRY IS EXPECTED...ALTHOUGH LESS
CONFIDENCE DUE TO THE EC ON WED. EXPECTING THE RIDGE IN THE WEST
TO AMPLIFY WITH HIGHS WARMING BACK INTO THE 40S AND EVEN A FEW
50S BY FRIDAY.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SUNDAY AFTERNOON)
ISSUED AT 1228 PM CST SAT DEC 28 2013
STRONG ARCTIC COLD FRONT MOVING SOUTHEAST ACROSS THE AREA THIS
AFTERNOON. DETERIORATING CONDITIONS EXPECTED ACROSS NORTHERN NEBRASKA
WITH POSSIBLE MVFR CEILINGS AND PATCHY FREEZING DRIZZLE. OTHERWISE
GUSTY WINDS WITH NORTHWEST WINDS 25 TO 35 KTS. FARTHER SOUTH
ACROSS SOUTHWEST NEBRASKA...WINDS WILL INCREASE TO 15 TO 30 KTS.
AT THIS TIME ANY FREEZING DRIZZLE AND LOWER CEILINGS SHOULD REMAIN
NORTH OF SOUTHWEST NEBRASKA.
&&
.LBF WATCHES/WARNINGS/ADVISORIES...
WIND ADVISORY UNTIL MIDNIGHT CST /11 PM MST/ TONIGHT FOR NEZ005-
006-008-009-022>026-035>037-056-057-094.
WIND ADVISORY UNTIL 3 AM CST SUNDAY FOR NEZ007-010-027>029-038.
&&
$$
UPDATE...TAYLOR
SHORT TERM...POWER
LONG TERM...MASEK
AVIATION...TAYLOR
AREA FORECAST DISCUSSION
NWS NORTH PLATTE NE
1226 PM CST SAT DEC 28 2013
.UPDATE...
ISSUED AT 1212 PM CST SAT DEC 28 2013
HAVE EXPANDED THE WIND ADVISORY TO INCLUDE THE WESTERN SANDHILLS
INTO THE SOUTHERN PANHANDLE. VERY STRONG PRESSURE RISES WILL SLIDE
ACROSS THE AREA THIS AFTERNOON...WITH BOTH THE RAP AND NAM MODELS
INDICATING 500 METER WIND SPEEDS APPROACHING 40 KTS. IT IS
POSSIBLE THAT NEAR HIGH WIND WARNING WIND SPEEDS COULD BE REACHED
ACROSS NORTH CENTRAL NEBRASKA FROM MID AFTERNOON THROUGH EARLY
EVENING...AND WILL MONITOR THIS CLOSELY. HAVE SEEN 65 MPH WIND
GUSTS LATE THIS MORNING ACROSS NORTHWEST SOUTH DAKOTA. STILL
COULD SEE SOME PATCHY FREEZING DRIZZLE...AS SOUNDINGS CONTINUE TO
INDICATE A NARROW WINDOW FOR THIS POTENTIAL ACROSS NORTHERN
NEBRASKA.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 333 AM CST SAT DEC 28 2013
MODELS IN FAIR AGREEMENT WITH TIMING OF FRONT AND HAVE USED A
BLEND. WINDS AND PRECIPITATION TYPE WILL BE NEAR TERM CONCERNS.
SURFACE LOW CENTERED NEAR CANADIAN EASTERN MONTANA BORDER WITH
SURFACE TROUGH INTO THE WESTERN NEBRASKA PANHANDLE INTO NORTHEAST
COLORADO. COLD FRONT ALONG MONTANA CANADIAN BORDER. 3HR PRESSURE
CHANGES HAVE A STRONG 10MB RISE OVER NORTH CENTRAL MONTANA WITH
-3MB PRESSURE FALLS INTO THE DAKOTAS. LEADING EDGE OF COLD FRONT
TO DROP THROUGH MOST OF THE CWA BY 18Z TODAY. HIGH TEMPERATURES
EARLY WITH RAPIDLY FALLING TEMPERATURES THROUGH THE AFTERNOON.
HAVE TRENDED LOWER WITH HIGHS WITH UPPER 30S NORTHWEST AND AROUND
50 TO THE SOUTHWEST. THESE MAY HAVE TO BE TRENDED DOWNWARD. TIGHT
PRESSURE GRADIENT AND WIND ADVISORY WINDS DEVELOP 18Z THROUGH
MIDNIGHT. WILL CONTINUE GOING WIND ADVISORY. THIS AFTERNOON TIME
HEIGHTS OVER NORTHERN NEBRASKA HAVE INCREASING LOW LEVEL RH WITH
WEAK LIFT AND DRY LAYER 800MB AND ABOVE. BUFR SOUNDINGS
INDICATIVE OF FREEZING DRIZZLE. HAVE CUT BACK ON START OF
PRECIPITATION BUT CARRIED LIGHT FREEZING DRIZZLE OR LIGHT SNOW
SHOWERS. AFTER 00Z CARRIED SNOW SHOWERS. MINIMAL CHANCES
GENERALLY NORTH OF HIGHWAY 2. WITH PARTIAL CLEARING TONIGHT
TEMPERATURES TO DROP SIGNIFICANTLY WITH COLDER AIR OVER NORTHWEST
WHERE THERE IS STILL SOME SNOW COVER AS 1040MB HIGH NOSES INTO
NORTHERN NEBRASKA. STRONG NORTHWEST WINDS AND SOME CLOUD COVER
MAY KEEP TEMPERATURES FROM REACHING THEIR FULL POTENTIAL.
.LONG TERM...(SUNDAY THROUGH FRIDAY)
ISSUED AT 333 AM CST SAT DEC 28 2013
SUNDAY MORNING THE ARCTIC HIGH PRESSURE WILL STRETCH FROM THE
NORTHERN PLAINS TO THE CENTRAL PLAINS. RESULTING IN MUCH COOLER
AIR ACROSS THE REGION. LATE IN THE DAY...AS THE HIGH PUSHES
EAST...850 MB TEMPS ON THE INCREASE. THIS WILL ALLOW FOR FAR SW
TO REBOUND CLOSE TO 30...OTHERWISE TEENS ACROSS N CENTRAL WITH
20S ELSEWHERE. THE HIGH WILL ALSO BRING DRY CONDITIONS. WAA
CONTINUES SUNDAY NIGHT AS THE HIGH CONTINUES TO DRIFT SE.
OVERNIGHT TEMPS STILL CHILLY...SINGLE DIGITS AND TEENS AS MODELS
IN GOOD AGREEMENT WITH THE BL STILL DECOUPLING.
EARLY NEXT WEEK THE MAIN FLOW IS NW ACROSS THE HIGH PLAINS. A
COUPLE OF CLIPPERS ARE EXPECTED TO QUICKLY MOVE ACROSS THE AREA.
CLOUDS ARE EXPECTED WITH EACH WAVE...HOWEVER UNSURE ON PRECIP.
MODELS INDICATE TOP DOWN SATURATION AND A SLOWLY INCREASING LOW
LEVEL MOISTURE FIELD WITH EACH PASSING WAVE. PRECIPITABLE WATERS
MONDAY MORNING START OUT NEAR THE 50 PERCENTILE /0.30 INCHES/ AND
INCREASE TO ABOVE THE 75 PERCENTILE /AROUND 0.45 INCHES/ BY
TUESDAY AFTERNOON/EVENING. WHILE LIFT IS LIMITED OVER THE CWA
WITH THE BETTER LIFT TO THE NORTH ACROSS S DAKOTA...SOME MODEL
AGREEMENT TUES/TUES NIGHT FOR GETTING SOME SNOWFALL TO REACH THE
GROUND. ONE NOTE IS THE EC IS A LITTLE SLOWER...AND AN OUTLIER AT
THIS TIME...KEEPING THINGS DRY UNTIL WEDNESDAY.
TO START THE NEW YEAR...WED INTO FRIDAY...A SEASONAL TO
SEASONALLY WARM PERIOD AND DRY IS EXPECTED...ALTHOUGH LESS
CONFIDENCE DUE TO THE EC ON WED. EXPECTING THE RIDGE IN THE WEST
TO AMPLIFY WITH HIGHS WARMING BACK INTO THE 40S AND EVEN A FEW
50S BY FRIDAY.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SUNDAY MORNING)
ISSUED AT 6 AM CST SAT DEC 28 2013
MAIN AVIATION CONCERNS IN THIS FORECAST WILL BE WINDS AND PATCHY
FREEZING DRIZZLE WITH STRONG COLD FRONTAL PASSAGE TODAY. LIGHT AND
VARIABLE WINDS EARLY THIS MORNING WILL BECOME NORTHWEST THROUGH
THE MORNING AND INCREASE THROUGH THE AFTERNOON WITH THE STRONGEST
WINDS DEVELOPING AFTER NOON CST. NORTHWEST WINDS AT 25 TO 35KTS
OVER MOST OF WESTERN NEBRASKA THIS AFTERNOON AND EVENING. PATCHY FREEZING
DRIZZLE IS ALSO POSSIBLE THIS AFTERNOON OVER NORTHERN NEBRASKA BUT
CONFIDENCE IS NOT STRONG ENOUGH TO MAKE THIS PREVAILING AND HAVE
IT IN TEMPO GROUP THROUGH THE LATE AFTERNOON IN KVTN TAF. LIGHT
SNOW SHOWERS OR FLURRIES ARE POSSIBLE THROUGH THE EVENING BUT HAVE
LEFT OUT FOR NOW.
&&
.LBF WATCHES/WARNINGS/ADVISORIES...
WIND ADVISORY UNTIL MIDNIGHT CST /11 PM MST/ TONIGHT FOR NEZ005-
006-008-009-022>026-035>037-056-057-094.
WIND ADVISORY UNTIL 3 AM CST SUNDAY FOR NEZ007-010-027>029-038.
&&
$$
UPDATE...TAYLOR
SHORT TERM...POWER
LONG TERM...MASEK
AVIATION...POWER
AREA FORECAST DISCUSSION
NWS OMAHA/VALLEY NE
1153 AM CST SAT DEC 28 2013
.AVIATION...
18Z TAFS FOR KOMA...KLNK...KOFK.
A STRONG COLD FRONT WILL MOVE INTO THE AREA THIS AFTERNOON WITH
STRONG NORTHWEST TO NORTH WINDS SPREADING ACROSS THE AREA BEHIND
THE FRONT. STRONG WINDS ARE EXPECTED TO CONTINUE THROUGH MOST
OF THE PERIOD WITH VFR CIGS.
&&
.PREV DISCUSSION... /ISSUED 1015 AM CST SAT DEC 28 2013/
UPDATE...
INCREASED MAX TEMPERATURES FOR TODAY BASED ON RAP FORECAST
SOUNDINGS MIXING FROM 950MB.
PREV DISCUSSION... /ISSUED 305 AM CST SAT DEC 28 2013/
DISCUSSION...
POTENTIAL FOR A WIND ADVISORY AND WIND CHILL ADVISORY WILL BE THE
MAIN FORECAST CONCERNS IN THIS PERIOD...BUT WILL ALSO NEED TO LOOK
CLOSELY AT TEMPERATURES AND THE CHANCE FOR LIGHT PCPN.
UPPER AIR CHARTS FROM LAST EVENING SHOWED A MODEST 100+ KNOT JET MAX
AT 300 MB DIVING SOUTHEAST TOWARD THE PACIFIC NORTHWEST. AT 500 MB
HEIGHT FALLS OF UP TO 160 METERS WERE NOTED WITH THE SHORTWAVE
TROUGH EXTENDING FROM BRITISH COLUMBIA AND ALBERTA DOWN INTO
NORTHERN CALIFORNIA. AT 850 MB...VERY MILD AIR...WITH TEMPERATURES
FROM 5-10 DEGREES CELSIUS WAS NOTED ACROSS THE CENTRAL PLAINS. VERY
COLD AIR WAS POISED TO THE NORTH...OVER ALBERTA AND SASKATCHEWAN.
LOW PRESSURE WILL MOVE RAPIDLY EAST/SOUTHEAST ACROSS THE DAKOTAS AND
MINNESOTA TODAY...AND A STRONG COLD FRONT WILL DROP SOUTHWARD ACROSS
THE PLAINS. THIS WILL BRING A WIND SHIFT TO THE LOCAL AREA LATER
THIS AFTERNOON AND EVENING. TEMPERATURES AHEAD OF THE FRONT SHOULD
TOP OUT IN THE 50S AT MANY LOCATIONS. IN OUR FAR NORTHWEST...WHERE
THE COLD AIR WILL MOVE IN EARLIEST...HIGHS MAY BE HELD TO THE 40S.
SOME UPPER 40S ALSO APPEAR POSSIBLE OVER LINGERING SNOW COVER
NEAR THE MISSOURI BORDER.
FOR AT LEAST MOST OF THE DAY...WINDS ARE EXPECTED TO REMAIN BELOW
ADVISORY LEVELS. THE FAR NORTHWEST ZONES MAY GET CLOSE TO 30 MPH
SUSTAINED BY LATE AFTERNOON. THE DAY SHIFT WILL NEED TO MONITOR
THIS. THE COMBINATION OF STRONG WINDS AND COLD TEMPERATURES WILL
CAUSE WIND CHILLS TO DROP TO AROUND 20 BELOW ZERO BY MIDNIGHT AT
LEAST IN OUR NORTHERN ZONES...AND A WIND CHILL ADVISORY MAY BE
NEEDED. WINDS WILL REMAIN FAIRLY STRONG INTO SUNDAY MORNING...AS
A 1040 MB HIGH PRESSURE CENTER CONTINUES TO BUILD SOUTHEAST
ACROSS THE DAKOTAS.
OTHERWISE...MODELS SHOW LOW LEVELS BECOMING SATURATED THIS
EVENING AS THE COLD AIR POURS IN. BUT FOR A WHILE...THERE MAY NOT
BE ANY ICE CRYSTALS ALOFT. THIS SUGGESTS THAT IF LIGHT PCPN
FALLS...IT MAYBE DRIZZLE OR FREEZING DRIZZLE AT LEAST BRIEFLY
UNTIL THE COLD AIR BECOMES DEEP ENOUGH TO CHANGE THE PCPN TO
FLURRIES/LIGHT SNOW. AS THE HIGH PRESSURE RIDGE BUILDS OVER THE
AREA SUNDAY AFTERNOON INTO SUNDAY EVENING...WINDS WILL SLACKEN.
WEAK LOW LEVEL WARM AIR ADVECTION SHOULD START AT LEAST IN OUR
WESTERN ZONES SUNDAY NIGHT...AS LOW PRESSURE MOVES INTO WESTERN
SOUTH DAKOTA AND SOUTHERLY WINDS RETURN. INCREASED HIGHS JUST A
BIT ON MONDAY...WITH LACK OF SNOW ON THE GROUND AND DECENT MIXING
EXPECTED. PCPN WITH THE LOW PRESSURE SYSTEM MOVING THROUGH THE
REGION ON MONDAY SHOULD STAY TO OUR NORTH.
SNOW CHANCES LOOK A LITTLE BETTER ON TUESDAY AND INTO TUESDAY NIGHT
FOR ABOUT THE NORTHERN HALF OF THE FORECAST AREA. THIS WILL BE IN
A TIGHT BAROCLINIC ZONE WITH SOME MID LEVEL FORCING.
DETAILS OF THE FORECAST BECOME LESS CLEAR BY WEDNESDAY AND THURSDAY
SO CONFIDENCE DROPS TO AROUND OR BELOW AVERAGE BY THEN. GENERALLY
USED A MODEL FOR WEDNESDAY THROUGH FRIDAY.
MILLER
AVIATION...
06Z TAFS FOR KOMA...KLNK...KOFK.
VFR CONDITIONS ARE EXPECTED THROUGH SATURDAY EVENING. CLEAR SKIES
AND SOUTH TO SOUTHWEST WINDS WILL PREVAIL OVERNIGHT...WITH
SOUTHWEST WINDS INCREASING TOWARD 15KT BY 18Z. A STRONG COLD FRONT
WILL PLUNGE THROUGH EASTERN NEBRASKA LATE SATURDAY AFTERNOON AND
EVENING ARRIVING AT KOFK BY 21Z THEN KLNK AND KOMA BY 00Z. WINDS
WILL BECOME NORTHWEST THEN NORTH AND INCREASE INTO THE 25 TO 35KT
RANGE BEFORE 06Z. VFR CIGS NEAR FL040 ARE EXPECTED BEHIND THE
FRONT...BUT AREAS OF MVFR CIGS AND FLURRIES COULD ALSO OCCUR.
DERGAN
&&
.OAX WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
IA...NONE.
&&
$$
FOBERT
AREA FORECAST DISCUSSION
NWS OMAHA/VALLEY NE
1015 AM CST SAT DEC 28 2013
.UPDATE...
INCREASED MAX TEMPERATURES FOR TODAY BASED ON RAP FORECAST
SOUNDINGS MIXING FROM 950MB.
&&
.PREV DISCUSSION... /ISSUED 614 AM CST SAT DEC 28 2013/
AVIATION...
12Z TAFS FOR KOMA...KLNK...KOFK.
MAIN AVN ISSUES THIS MORNING ARE LOW CIGS/WIND SHIFT ASSOCIATED
WITH ARCTIC FRONT MOVING INTO ERN NEB LATER TODAY. LATEST OBS
INDICATE DEEP SFC LOW WAS CENTERED OVER ERN ND WITH ATTENDANT COLD
FRONT STRADDLING MT/CANADIAN BORDER. A GRADUAL WIND SHIFT TO NW WILL
PROCEDE INCOMING MVFR CIGS AT ALL TERMINALS. EXPECT WIND SHIFT AT
KOFK/KLNK AROUND 00Z...THEN KOMA TWD 02Z THIS EVENING. CIGS
GENERALLY FL025 AGL WITH NW WIND G35-45KT WILL THEN PREVAIL THE
REST OF THE FCST PD AT ALL SITES.
DEE
PREV DISCUSSION... /ISSUED 305 AM CST SAT DEC 28 2013/
DISCUSSION...
POTENTIAL FOR A WIND ADVISORY AND WIND CHILL ADVISORY WILL BE THE
MAIN FORECAST CONCERNS IN THIS PERIOD...BUT WILL ALSO NEED TO LOOK
CLOSELY AT TEMPERATURES AND THE CHANCE FOR LIGHT PCPN.
UPPER AIR CHARTS FROM LAST EVENING SHOWED A MODEST 100+ KNOT JET MAX
AT 300 MB DIVING SOUTHEAST TOWARD THE PACIFIC NORTHWEST. AT 500 MB
.HEIGHT FALLS OF UP TO 160 METERS WERE NOTED WITH THE SHORTWAVE
TROUGH EXTENDING FROM BRITISH COLUMBIA AND ALBERTA DOWN INTO
NORTHERN CALIFORNIA. AT 850 MB...VERY MILD AIR...WITH TEMPERATURES
FROM 5-10 DEGREES CELSIUS WAS NOTED ACROSS THE CENTRAL PLAINS. VERY
COLD AIR WAS POISED TO THE NORTH...OVER ALBERTA AND SASKATCHEWAN.
LOW PRESSURE WILL MOVE RAPIDLY EAST/SOUTHEAST ACROSS THE DAKOTAS AND
MINNESOTA TODAY...AND A STRONG COLD FRONT WILL DROP SOUTHWARD ACROSS
THE PLAINS. THIS WILL BRING A WIND SHIFT TO THE LOCAL AREA LATER
THIS AFTERNOON AND EVENING. TEMPERATURES AHEAD OF THE FRONT SHOULD
TOP OUT IN THE 50S AT MANY LOCATIONS. IN OUR FAR NORTHWEST...WHERE
THE COLD AIR WILL MOVE IN EARLIEST...HIGHS MAY BE HELD TO THE 40S.
SOME UPPER 40S ALSO APPEAR POSSIBLE OVER LINGERING SNOW COVER
NEAR THE MISSOURI BORDER.
FOR AT LEAST MOST OF THE DAY...WINDS ARE EXPECTED TO REMAIN BELOW
ADVISORY LEVELS. THE FAR NORTHWEST ZONES MAY GET CLOSE TO 30 MPH
SUSTAINED BY LATE AFTERNOON. THE DAY SHIFT WILL NEED TO MONITOR
THIS. THE COMBINATION OF STRONG WINDS AND COLD TEMPERATURES WILL
CAUSE WIND CHILLS TO DROP TO AROUND 20 BELOW ZERO BY MIDNIGHT AT
LEAST IN OUR NORTHERN ZONES...AND A WIND CHILL ADVISORY MAY BE
NEEDED. WINDS WILL REMAIN FAIRLY STRONG INTO SUNDAY MORNING...AS
A 1040 MB HIGH PRESSURE CENTER CONTINUES TO BUILD SOUTHEAST
ACROSS THE DAKOTAS.
OTHERWISE...MODELS SHOW LOW LEVELS BECOMING SATURATED THIS
EVENING AS THE COLD AIR POURS IN. BUT FOR A WHILE...THERE MAY NOT
BE ANY ICE CRYSTALS ALOFT. THIS SUGGESTS THAT IF LIGHT PCPN
FALLS...IT MAYBE DRIZZLE OR FREEZING DRIZZLE AT LEAST BRIEFLY
UNTIL THE COLD AIR BECOMES DEEP ENOUGH TO CHANGE THE PCPN TO
FLURRIES/LIGHT SNOW. AS THE HIGH PRESSURE RIDGE BUILDS OVER THE
AREA SUNDAY AFTERNOON INTO SUNDAY EVENING...WINDS WILL SLACKEN.
WEAK LOW LEVEL WARM AIR ADVECTION SHOULD START AT LEAST IN OUR
WESTERN ZONES SUNDAY NIGHT...AS LOW PRESSURE MOVES INTO WESTERN
SOUTH DAKOTA AND SOUTHERLY WINDS RETURN. INCREASED HIGHS JUST A
BIT ON MONDAY...WITH LACK OF SNOW ON THE GROUND AND DECENT MIXING
EXPECTED. PCPN WITH THE LOW PRESSURE SYSTEM MOVING THROUGH THE
REGION ON MONDAY SHOULD STAY TO OUR NORTH.
SNOW CHANCES LOOK A LITTLE BETTER ON TUESDAY AND INTO TUESDAY NIGHT
FOR ABOUT THE NORTHERN HALF OF THE FORECAST AREA. THIS WILL BE IN
A TIGHT BAROCLINIC ZONE WITH SOME MID LEVEL FORCING.
DETAILS OF THE FORECAST BECOME LESS CLEAR BY WEDNESDAY AND THURSDAY
SO CONFIDENCE DROPS TO AROUND OR BELOW AVERAGE BY THEN. GENERALLY
USED A MODEL FOR WEDNESDAY THROUGH FRIDAY.
MILLER
AVIATION...
06Z TAFS FOR KOMA...KLNK...KOFK.
VFR CONDITIONS ARE EXPECTED THROUGH SATURDAY EVENING. CLEAR SKIES
AND SOUTH TO SOUTHWEST WINDS WILL PREVAIL OVERNIGHT...WITH
SOUTHWEST WINDS INCREASING TOWARD 15KT BY 18Z. A STRONG COLD FRONT
WILL PLUNGE THROUGH EASTERN NEBRASKA LATE SATURDAY AFTERNOON AND
EVENING ARRIVING AT KOFK BY 21Z THEN KLNK AND KOMA BY 00Z. WINDS
WILL BECOME NORTHWEST THEN NORTH AND INCREASE INTO THE 25 TO 35KT
RANGE BEFORE 06Z. VFR CIGS NEAR FL040 ARE EXPECTED BEHIND THE
FRONT...BUT AREAS OF MVFR CIGS AND FLURRIES COULD ALSO OCCUR.
DERGAN
&&
.OAX WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
IA...NONE.
&&
$$
FOBERT
AREA FORECAST DISCUSSION
NWS GRAND FORKS ND
203 PM CST SAT DEC 28 2013
.UPDATE...
ISSUED AT 203 PM CST SAT DEC 28 2013
REPORTS INDICATE NEAR ZERO VSBY INTO GRIGGS AND TRAILL
COUNTIES...AND VERY STRONG WINDS HAVE EXPANDED INTO THE SOUTHERN
RED RIVER VALLEY. LATEST RAP GUIDANCE INDICATES THE POTENTIAL FOR
WINDS TO INCREASE ANOTHER 5-10 KNOTS UNTIL 00Z...THEN SLOWLY
DIMINISH. IT IS NOT TAKING MUCH FALLING SNOW TO SIGNIFICANTLY
LOWER VISIBILITIES...AND MOST GUIDANCE INDICATES -SN WILL MOVE
INTO THE SOUTHERN FA LATER THIS AFTERNOON INTO THE EARLY EVENING
HOURS. GIVEN THESE FACTORS...FEEL CONFIDENT THAT AT LEAST THE OPEN
AREAS WILL HAVE VSBY 1/4SM WHERE WINDS ARE AOA 30MPH. PLUS...GIVEN
WINDS GUSTING TO 50 MPH ALONG WITH THE RAPIDLY COOLING
TEMPS...THERE IS A DECENT CHANCE FOR THE CRUST TO BE BROKEN
ADDING TO THE AVAILABLE SNOWFALL TO BLOW AROUND.
UPDATE ISSUED AT 1242 PM CST SAT DEC 28 2013
CURRENT HEADLINES SHOULD BE IN GOOD SHAPE. AWOS/ASOS SITES HAVE
IMPROVED VSBY SLIGHTLY WITHIN THE BLIZZARD WARNING AREA...BUT
STILL GETTING REPORTS OF WHITEOUT CONDITIONS (ESPECIALLY IN OPEN
AREAS). SNOW WILL INCREASE ACROSS THIS AREA DURING THE AFTERNOON
(AND WINDS SHOULD ALSO INCREASE A BIT)...WHICH WILL AGAIN CAUSE
THE WHITEOUT CONDITIONS TO INCREASE IN COVERAGE. TO THE
SOUTH...WINDS HAVE INCREASED BUT VSBY REMAINS AOA 1/2SM. WILL NEED
TO MONITOR VSBY SINCE WINDS WILL BE QUITE STRONG...IT IS POSSIBLE
THAT THE CRUST WILL BREAK AND ALLOW FOR MORE AVAILABLE SNOW TO
BLOW AROUND.
UPDATE ISSUED AT 1106 AM CST SAT DEC 28 2013
GETTING REPORTS OF BLIZZARD CONDITIONS WITHIN GRAND FORKS
COUNTY...AS WELL AS THE MINOT AREA (WHERE MODERATE SNOW IS
FALLING). WINDS CONTINUE TO INCREASE...WITH KDVL NOW 30G34KT.
CONFIDENCE IS ENOUGH THAT AT LEAST OPEN COUNTRY WILL BE WHITEOUT
CONDITIONS...ESPECIALLY AS THE MODERATE SNOW MOVES INTO THE DEVILS
LAKE BASIN AND NORTHERN VALLEY...AND HAVE EXPANDED THE BLIZZARD
WARNING SOUTHWARD. THERE IS SOME CONCERN THAT THE CRUST IS
BREAKING APART...WHICH COULD LEAD TO BLIZZARD CONDITIONS INTO THE
SOUTHERN RED RIVER VALLEY. AT THIS TIME THINKING THIS WILL NOT
OCCUR...BUT DEFINITELY WILL NEED TO MONITOR. LATEST RAP GUIDANCE
INDICATES THE MODERATE SNOWFALL WILL NOT DROP SOUTH OF THE CURRENT
BLIZZARD AREA...SO THAT MAY BE ENOUGH TO KEEP THE SOUTHERN VALLEY
A HIGH END WINTER WX ADVISORY.
UPDATE ISSUED AT 1029 AM CST SAT DEC 28 2013
MAIN CHALLENGE WILL BE WHERE/IF BLIZZARD CONDITIONS MAY DEVELOP.
LATEST OBSERVATIONS SUGGEST THAT MOST AREAS NEAR THE INTERNATIONAL
BORDER ARE WITHIN MAINLY WHITEOUT CONDITIONS...AND WINDS CONTINUE
TO INCREASE. LATEST GUIDANCE SUGGESTS THAT MOST AREAS (ESPECIALLY
ALONG AND WEST OF THE VALLEY) WILL BE SUSTAINED 35 MPH WITH GUSTS
TO 50 MPH THIS AFTERNOON. THE LATEST RAP GUIDANCE INDICATES MIXING
AND UNIDIRECTIONAL FLOW TO 950MB...WHERE THERE IS 40-43 KNOTS
AVAILABLE. CURRENTLY...THE LOW VISIBILITIES ARE RELATED TO AREAS
THAT RECEIVED SNOWFALL OVER THE PAST 6-10 HOURS. HOWEVER...WE ARE
GETTING REPORTS THAT THE CRUST MAY BE BREAKING APART WHERE WINDS
ARE GUSTING TO NEAR 40 KNOTS. FOR NOW...HAVE UPGRADED TO A
BLIZZARD WARNING FOR AREAS NEAR THE INTERNATIONAL BORDER TO THE
NORTHERN VALLEY. THERE IS ANOTHER BAND OF SNOW...ASSOCIATED WITH
STRONG 850MB-700MB FRONTOGENESIS...THAT WILL DROP INTO THE DEVILS
LAKE BASIN AND CENTRAL RED RIVER VALLEY THIS AFTERNOON. THIS MAY
BE ENOUGH THAT THE BLIZZARD WARNING MAY NEED TO BE EXPANDED SOUTH
TO COVER THIS AREA. WILL MONITOR THE SITUATION AND LIKELY MAKE A
DECISION BY NOON/1PM.
INCREASED WIND SPEEDS IN THE GRIDS BASED ON LATEST OBSERVATIONS
AND GUIDANCE.
ALSO...INCLUDED ALL AREAS IN FREEZING DRIZZLE SOUTH OF THE MAIN
COLD AIR ADVECTION.
&&
.SHORT TERM...(TODAY THROUGH SUNDAY)
ISSUED AT 359 AM CST SAT DEC 28 2013
WATER VAPOR LOOP INDICATED A SHORT WAVE OVER NORTH CENTRAL MT.
TROUGH WILL MOVE ACROSS THE FORECAST AREA TONIGHT. LEADING EDGE OF
ARCTIC AIR WAS LOCATED OVER CENTRAL MAN AND CENTRAL SASK OR THE
NORTHERN END OF LAKE WINNIPEG. ARCTIC AIR WILL SHIFT SOUTH TODAY.
ENHANCED IR SATELLITE LOOP AND ATMOSPHERIC PROFILE SUGGEST POTENTIAL
FOR FREEZING DRIZZLE FROM BJI TO CANDO ND. SOME FREEZING DRIZZLE HAS
HAS BEEN OCCURRING IN GFK THIS MORNING. WILL GO FOR FREEZING DRIZZLE
THROUGH 12Z SAT IN A ROUGHLY 90 MILE WIDE BAND FROM CANDO ND TO BJI.
EXPECT FREEZING DRIZZLE BAND TO SHIFT INTO MN SIDE FROM 12Z TO 18Z
SAT FROM ABOUT WASKISH TO CROOKSTON TO ADA TO PARK RAPIDS. FREEZING
PRECIP SHOULD MOVE EAST OF THE AREA THEREAFTER.
GOOD WINDS EXPECTED TO INCREASE LATER THIS MORNING AS SURFACE LOW
MOVES EAST. WINDS MAY GUST UP TO 40 MPH. WITH RELATIVELY MILD
TEMPERATURES YESTERDAY THE SNOW PACK IS EXPECTED TO HAVE A CRUST AS
TEMPERATURES FALL. WITH SNOW PACK CRUSTED, THEN SNOW WILL HAVE A
HARD TIME TO BLOW AROUND. ALSO SNOW AMOUNTS ARE NOT EXPECTED TO BE
AS MUCH AS THOUGHT YESTERDAY. AN INCH OR TWO OF SNOW IS FORECAST
ALONG THE INTERNATIONAL BORDER TO ONLY A DUSTING IN THE SOUTHERN RED
RIVER VALLEY. SO IF ANY POTENTIAL FOR BLIZZARD CONDITIONS WOULD BE
IN THE NORTHERN RED RIVER VALLEY WITH THE FALLING SNOW.
MESO SCALE ANALYSIS SHOWED BEST PRESSURE RISES AND LOW LEVEL COLD
ADVECTION WERE OCCURRING OVER NORTHWEST MT OR WEST OF THE SURFACE
LOW. SURFACE LOW WILL MOVE INTO SOUTHWEST MN THIS AFTERNOON.
WITH SUCH A WIDE VARIETY OF WEATHER EXPECTED TODAY, WILL ISSUE A
BLANKET WINTER WEATHER ADVISORY FOR THE ENTIRE AREA. LATER SHIFTS
WILL HAVE TO MONITOR FOR POTENTIAL BLIZZARD CONDITIONS FOR TODAY AND
TONIGHT AND AMEND IF NECESSARY.
.LONG TERM...(SUNDAY NIGHT THROUGH FRIDAY)
ISSUED AT 359 AM CST SAT DEC 28 2013
TUE THROUGH FRI...
IT WILL BE BITTERLY COLD TO BEGIN THE PERIOD WITH MODERATION BY NEXT
THU/FRI. THE BEST CHANCE FOR SOME LIGHT SNOW SHOULD COME BY THE
MIDDLE OF NEXT WEEK NEAR INCREASING MID LEVEL WAA...BUT NO MAJOR
STORMS EXPECTED...WITH THE MAIN WEATHER STORY BEING THE BRUTAL COLD.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SUNDAY AFTERNOON)
ISSUED AT 1242 PM CST SAT DEC 28 2013
EXPECT WIDESPREAD IFR CONDITIONS TODAY WITH CIGS GENERALLY RANGING
FROM 300 TO 500 FEET. SURFACE VISIBILITIES IN THE VALLEY AND ACROSS
EASTERN NORTH DAKOTA WILL RANGE FROM WHITE OUT CONDITIONS IN THE
NORTH TO ONE HALF TO TWO MILES ACROSS THE SOUTH AS NORTHERLY WINDS
GUST FROM 40 TO 50 MPH. WINDS WILL DECREASE FURTHER EAST...BUT STILL
RESULT IN SOME AREAS OF BLOWING SNOW. CONDITIONS WILL NOT IMPROVE
UNTIL LATE IN THE EVENING...AS CLOUDS CLEAR OUT AND WINDS DECLINE
ENOUGH TO END THE BLOWING SNOW.
&&
.FGF WATCHES/WARNINGS/ADVISORIES...
ND...BLIZZARD WARNING UNTIL MIDNIGHT CST TONIGHT FOR NDZ028>030-038-
039-049-052-053.
BLIZZARD WARNING UNTIL 9 PM CST THIS EVENING FOR NDZ006>008-
014>016-024-026-027-054.
MN...BLIZZARD WARNING UNTIL MIDNIGHT CST TONIGHT FOR MNZ002-003-029-
030-040.
WINTER WEATHER ADVISORY UNTIL MIDNIGHT CST TONIGHT FOR MNZ005-
006-008-009-013>017-022>024-027-028-031-032.
BLIZZARD WARNING UNTIL 9 PM CST THIS EVENING FOR MNZ001-004-007.
&&
$$
UPDATE...TG
SHORT TERM...HOPPES
LONG TERM...DK
AVIATION...SPEICHER
AREA FORECAST DISCUSSION
NWS GRAND FORKS ND
1242 PM CST SAT DEC 28 2013
.UPDATE...
ISSUED AT 1242 PM CST SAT DEC 28 2013
CURRENT HEADLINES SHOULD BE IN GOOD SHAPE. AWOS/ASOS SITES HAVE
IMPROVED VSBY SLIGHTLY WITHIN THE BLIZZARD WARNING AREA...BUT
STILL GETTING REPORTS OF WHITEOUT CONDITIONS (ESPECIALLY IN OPEN
AREAS). SNOW WILL INCREASE ACROSS THIS AREA DURING THE AFTERNOON
(AND WINDS SHOULD ALSO INCREASE A BIT)...WHICH WILL AGAIN CAUSE
THE WHITEOUT CONDITIONS TO INCREASE IN COVERAGE. TO THE
SOUTH...WINDS HAVE INCREASED BUT VSBY REMAINS AOA 1/2SM. WILL NEED
TO MONITOR VSBY SINCE WINDS WILL BE QUITE STRONG...IT IS POSSIBLE
THAT THE CRUST WILL BREAK AND ALLOW FOR MORE AVAILABLE SNOW TO
BLOW AROUND.
UPDATE ISSUED AT 1106 AM CST SAT DEC 28 2013
GETTING REPORTS OF BLIZZARD CONDITIONS WITHIN GRAND FORKS
COUNTY...AS WELL AS THE MINOT AREA (WHERE MODERATE SNOW IS
FALLING). WINDS CONTINUE TO INCREASE...WITH KDVL NOW 30G34KT.
CONFIDENCE IS ENOUGH THAT AT LEAST OPEN COUNTRY WILL BE WHITEOUT
CONDITIONS...ESPECIALLY AS THE MODERATE SNOW MOVES INTO THE DEVILS
LAKE BASIN AND NORTHERN VALLEY...AND HAVE EXPANDED THE BLIZZARD
WARNING SOUTHWARD. THERE IS SOME CONCERN THAT THE CRUST IS
BREAKING APART...WHICH COULD LEAD TO BLIZZARD CONDITIONS INTO THE
SOUTHERN RED RIVER VALLEY. AT THIS TIME THINKING THIS WILL NOT
OCCUR...BUT DEFINITELY WILL NEED TO MONITOR. LATEST RAP GUIDANCE
INDICATES THE MODERATE SNOWFALL WILL NOT DROP SOUTH OF THE CURRENT
BLIZZARD AREA...SO THAT MAY BE ENOUGH TO KEEP THE SOUTHERN VALLEY
A HIGH END WINTER WX ADVISORY.
UPDATE ISSUED AT 1029 AM CST SAT DEC 28 2013
MAIN CHALLENGE WILL BE WHERE/IF BLIZZARD CONDITIONS MAY DEVELOP.
LATEST OBSERVATIONS SUGGEST THAT MOST AREAS NEAR THE INTERNATIONAL
BORDER ARE WITHIN MAINLY WHITEOUT CONDITIONS...AND WINDS CONTINUE
TO INCREASE. LATEST GUIDANCE SUGGESTS THAT MOST AREAS (ESPECIALLY
ALONG AND WEST OF THE VALLEY) WILL BE SUSTAINED 35 MPH WITH GUSTS
TO 50 MPH THIS AFTERNOON. THE LATEST RAP GUIDANCE INDICATES MIXING
AND UNIDIRECTIONAL FLOW TO 950MB...WHERE THERE IS 40-43 KNOTS
AVAILABLE. CURRENTLY...THE LOW VISIBILITIES ARE RELATED TO AREAS
THAT RECEIVED SNOWFALL OVER THE PAST 6-10 HOURS. HOWEVER...WE ARE
GETTING REPORTS THAT THE CRUST MAY BE BREAKING APART WHERE WINDS
ARE GUSTING TO NEAR 40 KNOTS. FOR NOW...HAVE UPGRADED TO A
BLIZZARD WARNING FOR AREAS NEAR THE INTERNATIONAL BORDER TO THE
NORTHERN VALLEY. THERE IS ANOTHER BAND OF SNOW...ASSOCIATED WITH
STRONG 850MB-700MB FRONTOGENESIS...THAT WILL DROP INTO THE DEVILS
LAKE BASIN AND CENTRAL RED RIVER VALLEY THIS AFTERNOON. THIS MAY
BE ENOUGH THAT THE BLIZZARD WARNING MAY NEED TO BE EXPANDED SOUTH
TO COVER THIS AREA. WILL MONITOR THE SITUATION AND LIKELY MAKE A
DECISION BY NOON/1PM.
INCREASED WIND SPEEDS IN THE GRIDS BASED ON LATEST OBSERVATIONS
AND GUIDANCE.
ALSO...INCLUDED ALL AREAS IN FREEZING DRIZZLE SOUTH OF THE MAIN
COLD AIR ADVECTION.
&&
.SHORT TERM...(TODAY THROUGH SUNDAY)
ISSUED AT 359 AM CST SAT DEC 28 2013
WATER VAPOR LOOP INDICATED A SHORT WAVE OVER NORTH CENTRAL MT.
TROUGH WILL MOVE ACROSS THE FORECAST AREA TONIGHT. LEADING EDGE OF
ARCTIC AIR WAS LOCATED OVER CENTRAL MAN AND CENTRAL SASK OR THE
NORTHERN END OF LAKE WINNIPEG. ARCTIC AIR WILL SHIFT SOUTH TODAY.
ENHANCED IR SATELLITE LOOP AND ATMOSPHERIC PROFILE SUGGEST POTENTIAL
FOR FREEZING DRIZZLE FROM BJI TO CANDO ND. SOME FREEZING DRIZZLE HAS
HAS BEEN OCCURRING IN GFK THIS MORNING. WILL GO FOR FREEZING DRIZZLE
THROUGH 12Z SAT IN A ROUGHLY 90 MILE WIDE BAND FROM CANDO ND TO BJI.
EXPECT FREEZING DRIZZLE BAND TO SHIFT INTO MN SIDE FROM 12Z TO 18Z
SAT FROM ABOUT WASKISH TO CROOKSTON TO ADA TO PARK RAPIDS. FREEZING
PRECIP SHOULD MOVE EAST OF THE AREA THEREAFTER.
GOOD WINDS EXPECTED TO INCREASE LATER THIS MORNING AS SURFACE LOW
MOVES EAST. WINDS MAY GUST UP TO 40 MPH. WITH RELATIVELY MILD
TEMPERATURES YESTERDAY THE SNOW PACK IS EXPECTED TO HAVE A CRUST AS
TEMPERATURES FALL. WITH SNOW PACK CRUSTED, THEN SNOW WILL HAVE A
HARD TIME TO BLOW AROUND. ALSO SNOW AMOUNTS ARE NOT EXPECTED TO BE
AS MUCH AS THOUGHT YESTERDAY. AN INCH OR TWO OF SNOW IS FORECAST
ALONG THE INTERNATIONAL BORDER TO ONLY A DUSTING IN THE SOUTHERN RED
RIVER VALLEY. SO IF ANY POTENTIAL FOR BLIZZARD CONDITIONS WOULD BE
IN THE NORTHERN RED RIVER VALLEY WITH THE FALLING SNOW.
MESO SCALE ANALYSIS SHOWED BEST PRESSURE RISES AND LOW LEVEL COLD
ADVECTION WERE OCCURRING OVER NORTHWEST MT OR WEST OF THE SURFACE
LOW. SURFACE LOW WILL MOVE INTO SOUTHWEST MN THIS AFTERNOON.
WITH SUCH A WIDE VARIETY OF WEATHER EXPECTED TODAY, WILL ISSUE A
BLANKET WINTER WEATHER ADVISORY FOR THE ENTIRE AREA. LATER SHIFTS
WILL HAVE TO MONITOR FOR POTENTIAL BLIZZARD CONDITIONS FOR TODAY AND
TONIGHT AND AMEND IF NECESSARY.
.LONG TERM...(SUNDAY NIGHT THROUGH FRIDAY)
ISSUED AT 359 AM CST SAT DEC 28 2013
TUE THROUGH FRI...
IT WILL BE BITTERLY COLD TO BEGIN THE PERIOD WITH MODERATION BY NEXT
THU/FRI. THE BEST CHANCE FOR SOME LIGHT SNOW SHOULD COME BY THE
MIDDLE OF NEXT WEEK NEAR INCREASING MID LEVEL WAA...BUT NO MAJOR
STORMS EXPECTED...WITH THE MAIN WEATHER STORY BEING THE BRUTAL COLD.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SUNDAY AFTERNOON)
ISSUED AT 1242 PM CST SAT DEC 28 2013
EXPECT WIDESPREAD IFR CONDITIONS TODAY WITH CIGS GENERALLY RANGING
FROM 300 TO 500 FEET. SURFACE VISIBILITIES IN THE VALLEY AND ACROSS
EASTERN NORTH DAKOTA WILL RANGE FROM WHITE OUT CONDITIONS IN THE
NORTH TO ONE HALF TO TWO MILES ACROSS THE SOUTH AS NORTHERLY WINDS
GUST FROM 40 TO 50 MPH. WINDS WILL DECREASE FURTHER EAST...BUT STILL
RESULT IN SOME AREAS OF BLOWING SNOW. CONDITIONS WILL NOT IMPROVE
UNTIL LATE IN THE EVENING...AS CLOUDS CLEAR OUT AND WINDS DECLINE
ENOUGH TO END THE BLOWING SNOW.
&&
.FGF WATCHES/WARNINGS/ADVISORIES...
ND...WINTER WEATHER ADVISORY UNTIL MIDNIGHT CST TONIGHT FOR
NDZ028>030-038-039-049-052-053.
BLIZZARD WARNING UNTIL 9 PM CST THIS EVENING FOR NDZ006>008-
014>016-024-026-027-054.
MN...WINTER WEATHER ADVISORY UNTIL MIDNIGHT CST TONIGHT FOR MNZ002-
003-005-006-008-009-013>017-022>024-027>032-040.
BLIZZARD WARNING UNTIL 9 PM CST THIS EVENING FOR MNZ001-004-007.
&&
$$
UPDATE...TG
SHORT TERM...HOPPES
LONG TERM...DK
AVIATION...SPEICHER
AREA FORECAST DISCUSSION
NWS GRAND FORKS ND
1106 AM CST SAT DEC 28 2013
.UPDATE...
ISSUED AT 1106 AM CST SAT DEC 28 2013
GETTING REPORTS OF BLIZZARD CONDITIONS WITHIN GRAND FORKS
COUNTY...AS WELL AS THE MINOT AREA (WHERE MODERATE SNOW IS
FALLING). WINDS CONTINUE TO INCREASE...WITH KDVL NOW 30G34KT.
CONFIDENCE IS ENOUGH THAT AT LEAST OPEN COUNTRY WILL BE WHITEOUT
CONDITIONS...ESPECIALLY AS THE MODERATE SNOW MOVES INTO THE DEVILS
LAKE BASIN AND NORTHERN VALLEY...AND HAVE EXPANDED THE BLIZZARD
WARNING SOUTHWARD. THERE IS SOME CONCERN THAT THE CRUST IS
BREAKING APART...WHICH COULD LEAD TO BLIZZARD CONDITIONS INTO THE
SOUTHERN RED RIVER VALLEY. AT THIS TIME THINKING THIS WILL NOT
OCCUR...BUT DEFINITELY WILL NEED TO MONITOR. LATEST RAP GUIDANCE
INDICATES THE MODERATE SNOWFALL WILL NOT DROP SOUTH OF THE CURRENT
BLIZZARD AREA...SO THAT MAY BE ENOUGH TO KEEP THE SOUTHERN VALLEY
A HIGH END WINTER WX ADVISORY.
UPDATE ISSUED AT 1029 AM CST SAT DEC 28 2013
MAIN CHALLENGE WILL BE WHERE/IF BLIZZARD CONDITIONS MAY DEVELOP.
LATEST OBSERVATIONS SUGGEST THAT MOST AREAS NEAR THE INTERNATIONAL
BORDER ARE WITHIN MAINLY WHITEOUT CONDITIONS...AND WINDS CONTINUE
TO INCREASE. LATEST GUIDANCE SUGGESTS THAT MOST AREAS (ESPECIALLY
ALONG AND WEST OF THE VALLEY) WILL BE SUSTAINED 35 MPH WITH GUSTS
TO 50 MPH THIS AFTERNOON. THE LATEST RAP GUIDANCE INDICATES MIXING
AND UNIDIRECTIONAL FLOW TO 950MB...WHERE THERE IS 40-43 KNOTS
AVAILABLE. CURRENTLY...THE LOW VISIBILITIES ARE RELATED TO AREAS
THAT RECEIVED SNOWFALL OVER THE PAST 6-10 HOURS. HOWEVER...WE ARE
GETTING REPORTS THAT THE CRUST MAY BE BREAKING APART WHERE WINDS
ARE GUSTING TO NEAR 40 KNOTS. FOR NOW...HAVE UPGRADED TO A
BLIZZARD WARNING FOR AREAS NEAR THE INTERNATIONAL BORDER TO THE
NORTHERN VALLEY. THERE IS ANOTHER BAND OF SNOW...ASSOCIATED WITH
STRONG 850MB-700MB FRONTOGENESIS...THAT WILL DROP INTO THE DEVILS
LAKE BASIN AND CENTRAL RED RIVER VALLEY THIS AFTERNOON. THIS MAY
BE ENOUGH THAT THE BLIZZARD WARNING MAY NEED TO BE EXPANDED SOUTH
TO COVER THIS AREA. WILL MONITOR THE SITUATION AND LIKELY MAKE A
DECISION BY NOON/1PM.
INCREASED WIND SPEEDS IN THE GRIDS BASED ON LATEST OBSERVATIONS
AND GUIDANCE.
ALSO...INCLUDED ALL AREAS IN FREEZING DRIZZLE SOUTH OF THE MAIN
COLD AIR ADVECTION.
&&
.SHORT TERM...(TODAY THROUGH SUNDAY)
ISSUED AT 359 AM CST SAT DEC 28 2013
WATER VAPOR LOOP INDICATED A SHORT WAVE OVER NORTH CENTRAL MT.
TROUGH WILL MOVE ACROSS THE FORECAST AREA TONIGHT. LEADING EDGE OF
ARCTIC AIR WAS LOCATED OVER CENTRAL MAN AND CENTRAL SASK OR THE
NORTHERN END OF LAKE WINNIPEG. ARCTIC AIR WILL SHIFT SOUTH TODAY.
ENHANCED IR SATELLITE LOOP AND ATMOSPHERIC PROFILE SUGGEST POTENTIAL
FOR FREEZING DRIZZLE FROM BJI TO CANDO ND. SOME FREEZING DRIZZLE HAS
HAS BEEN OCCURRING IN GFK THIS MORNING. WILL GO FOR FREEZING DRIZZLE
THROUGH 12Z SAT IN A ROUGHLY 90 MILE WIDE BAND FROM CANDO ND TO BJI.
EXPECT FREEZING DRIZZLE BAND TO SHIFT INTO MN SIDE FROM 12Z TO 18Z
SAT FROM ABOUT WASKISH TO CROOKSTON TO ADA TO PARK RAPIDS. FREEZING
PRECIP SHOULD MOVE EAST OF THE AREA THEREAFTER.
GOOD WINDS EXPECTED TO INCREASE LATER THIS MORNING AS SURFACE LOW
MOVES EAST. WINDS MAY GUST UP TO 40 MPH. WITH RELATIVELY MILD
TEMPERATURES YESTERDAY THE SNOW PACK IS EXPECTED TO HAVE A CRUST AS
TEMPERATURES FALL. WITH SNOW PACK CRUSTED, THEN SNOW WILL HAVE A
HARD TIME TO BLOW AROUND. ALSO SNOW AMOUNTS ARE NOT EXPECTED TO BE
AS MUCH AS THOUGHT YESTERDAY. AN INCH OR TWO OF SNOW IS FORECAST
ALONG THE INTERNATIONAL BORDER TO ONLY A DUSTING IN THE SOUTHERN RED
RIVER VALLEY. SO IF ANY POTENTIAL FOR BLIZZARD CONDITIONS WOULD BE
IN THE NORTHERN RED RIVER VALLEY WITH THE FALLING SNOW.
MESO SCALE ANALYSIS SHOWED BEST PRESSURE RISES AND LOW LEVEL COLD
ADVECTION WERE OCCURRING OVER NORTHWEST MT OR WEST OF THE SURFACE
LOW. SURFACE LOW WILL MOVE INTO SOUTHWEST MN THIS AFTERNOON.
WITH SUCH A WIDE VARIETY OF WEATHER EXPECTED TODAY, WILL ISSUE A
BLANKET WINTER WEATHER ADVISORY FOR THE ENTIRE AREA. LATER SHIFTS
WILL HAVE TO MONITOR FOR POTENTIAL BLIZZARD CONDITIONS FOR TODAY AND
TONIGHT AND AMEND IF NECESSARY.
.LONG TERM...(SUNDAY NIGHT THROUGH FRIDAY)
ISSUED AT 359 AM CST SAT DEC 28 2013
TUE THROUGH FRI...
IT WILL BE BITTERLY COLD TO BEGIN THE PERIOD WITH MODERATION BY NEXT
THU/FRI. THE BEST CHANCE FOR SOME LIGHT SNOW SHOULD COME BY THE
MIDDLE OF NEXT WEEK NEAR INCREASING MID LEVEL WAA...BUT NO MAJOR
STORMS EXPECTED...WITH THE MAIN WEATHER STORY BEING THE BRUTAL COLD.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SUNDAY MORNING)
ISSUED AT 703 AM CST SAT DEC 28 2013
IFR CONDITIONS WERE LOCATED OVER THE NORTHEAST HALF OF THE FORECAST
AREA. SATELLITE LOOP/SURFACE OBS INDICATE HIGH CLOUDS COVER THE
AREA. EXPECT IFR CONDITIONS WILL SPREAD SOUTH FOR TODAY WITH PASSAGE
OF SURFACE LOW PRESSURE SYSTEM. VFR CONDITIONS MAY BE POSSIBLE OVER
EASTERN NORTH DAKOTA AFTER MID EVENING. EXPECT NORTH WIND OF 20 TO
30 MPH WITH HIGHER GUST FOR TODAY.
&&
.FGF WATCHES/WARNINGS/ADVISORIES...
ND...WINTER WEATHER ADVISORY UNTIL MIDNIGHT CST TONIGHT FOR
NDZ028>030-038-039-049-052-053.
BLIZZARD WARNING UNTIL 9 PM CST THIS EVENING FOR NDZ006>008-
014>016-024-026-027-054.
MN...WINTER WEATHER ADVISORY UNTIL MIDNIGHT CST TONIGHT FOR MNZ002-
003-005-006-008-009-013>017-022>024-027>032-040.
BLIZZARD WARNING UNTIL 9 PM CST THIS EVENING FOR MNZ001-004-007.
&&
$$
UPDATE...TG
SHORT TERM...HOPPES
LONG TERM...DK
AVIATION...HOPPES
AREA FORECAST DISCUSSION
NWS GRAND FORKS ND
1029 AM CST SAT DEC 28 2013
.UPDATE...
ISSUED AT 1029 AM CST SAT DEC 28 2013
MAIN CHALLENGE WILL BE WHERE/IF BLIZZARD CONDITIONS MAY DEVELOP.
LATEST OBSERVATIONS SUGGEST THAT MOST AREAS NEAR THE INTERNATIONAL
BORDER ARE WITHIN MAINLY WHITEOUT CONDITIONS...AND WINDS CONTINUE
TO INCREASE. LATEST GUIDANCE SUGGESTS THAT MOST AREAS (ESPECIALLY
ALONG AND WEST OF THE VALLEY) WILL BE SUSTAINED 35 MPH WITH GUSTS
TO 50 MPH THIS AFTERNOON. THE LATEST RAP GUIDANCE INDICATES MIXING
AND UNIDIRECTIONAL FLOW TO 950MB...WHERE THERE IS 40-43 KNOTS
AVAILABLE. CURRENTLY...THE LOW VISIBILITIES ARE RELATED TO AREAS
THAT RECEIVED SNOWFALL OVER THE PAST 6-10 HOURS. HOWEVER...WE ARE
GETTING REPORTS THAT THE CRUST MAY BE BREAKING APART WHERE WINDS
ARE GUSTING TO NEAR 40 KNOTS. FOR NOW...HAVE UPGRADED TO A
BLIZZARD WARNING FOR AREAS NEAR THE INTERNATIONAL BORDER TO THE
NORTHERN VALLEY. THERE IS ANOTHER BAND OF SNOW...ASSOCIATED WITH
STRONG 850MB-700MB FRONTOGENESIS...THAT WILL DROP INTO THE DEVILS
LAKE BASIN AND CENTRAL RED RIVER VALLEY THIS AFTERNOON. THIS MAY
BE ENOUGH THAT THE BLIZZARD WARNING MAY NEED TO BE EXPANDED SOUTH
TO COVER THIS AREA. WILL MONITOR THE SITUATION AND LIKELY MAKE A
DECISION BY NOON/1PM.
INCREASED WIND SPEEDS IN THE GRIDS BASED ON LATEST OBSERVATIONS
AND GUIDANCE.
ALSO...INCLUDED ALL AREAS IN FREEZING DRIZZLE SOUTH OF THE MAIN
COLD AIR ADVECTION.
&&
.SHORT TERM...(TODAY THROUGH SUNDAY)
ISSUED AT 359 AM CST SAT DEC 28 2013
WATER VAPOR LOOP INDICATED A SHORT WAVE OVER NORTH CENTRAL MT.
TROUGH WILL MOVE ACROSS THE FORECAST AREA TONIGHT. LEADING EDGE OF
ARCTIC AIR WAS LOCATED OVER CENTRAL MAN AND CENTRAL SASK OR THE
NORTHERN END OF LAKE WINNIPEG. ARCTIC AIR WILL SHIFT SOUTH TODAY.
ENHANCED IR SATELLITE LOOP AND ATMOSPHERIC PROFILE SUGGEST POTENTIAL
FOR FREEZING DRIZZLE FROM BJI TO CANDO ND. SOME FREEZING DRIZZLE HAS
HAS BEEN OCCURRING IN GFK THIS MORNING. WILL GO FOR FREEZING DRIZZLE
THROUGH 12Z SAT IN A ROUGHLY 90 MILE WIDE BAND FROM CANDO ND TO BJI.
EXPECT FREEZING DRIZZLE BAND TO SHIFT INTO MN SIDE FROM 12Z TO 18Z
SAT FROM ABOUT WASKISH TO CROOKSTON TO ADA TO PARK RAPIDS. FREEZING
PRECIP SHOULD MOVE EAST OF THE AREA THEREAFTER.
GOOD WINDS EXPECTED TO INCREASE LATER THIS MORNING AS SURFACE LOW
MOVES EAST. WINDS MAY GUST UP TO 40 MPH. WITH RELATIVELY MILD
TEMPERATURES YESTERDAY THE SNOW PACK IS EXPECTED TO HAVE A CRUST AS
TEMPERATURES FALL. WITH SNOW PACK CRUSTED, THEN SNOW WILL HAVE A
HARD TIME TO BLOW AROUND. ALSO SNOW AMOUNTS ARE NOT EXPECTED TO BE
AS MUCH AS THOUGHT YESTERDAY. AN INCH OR TWO OF SNOW IS FORECAST
ALONG THE INTERNATIONAL BORDER TO ONLY A DUSTING IN THE SOUTHERN RED
RIVER VALLEY. SO IF ANY POTENTIAL FOR BLIZZARD CONDITIONS WOULD BE
IN THE NORTHERN RED RIVER VALLEY WITH THE FALLING SNOW.
MESO SCALE ANALYSIS SHOWED BEST PRESSURE RISES AND LOW LEVEL COLD
ADVECTION WERE OCCURRING OVER NORTHWEST MT OR WEST OF THE SURFACE
LOW. SURFACE LOW WILL MOVE INTO SOUTHWEST MN THIS AFTERNOON.
WITH SUCH A WIDE VARIETY OF WEATHER EXPECTED TODAY, WILL ISSUE A
BLANKET WINTER WEATHER ADVISORY FOR THE ENTIRE AREA. LATER SHIFTS
WILL HAVE TO MONITOR FOR POTENTIAL BLIZZARD CONDITIONS FOR TODAY AND
TONIGHT AND AMEND IF NECESSARY.
.LONG TERM...(SUNDAY NIGHT THROUGH FRIDAY)
ISSUED AT 359 AM CST SAT DEC 28 2013
TUE THROUGH FRI...
IT WILL BE BITTERLY COLD TO BEGIN THE PERIOD WITH MODERATION BY NEXT
THU/FRI. THE BEST CHANCE FOR SOME LIGHT SNOW SHOULD COME BY THE
MIDDLE OF NEXT WEEK NEAR INCREASING MID LEVEL WAA...BUT NO MAJOR
STORMS EXPECTED...WITH THE MAIN WEATHER STORY BEING THE BRUTAL COLD.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SUNDAY MORNING)
ISSUED AT 703 AM CST SAT DEC 28 2013
IFR CONDITIONS WERE LOCATED OVER THE NORTHEAST HALF OF THE FORECAST
AREA. SATELLITE LOOP/SURFACE OBS INDICATE HIGH CLOUDS COVER THE
AREA. EXPECT IFR CONDITIONS WILL SPREAD SOUTH FOR TODAY WITH PASSAGE
OF SURFACE LOW PRESSURE SYSTEM. VFR CONDITIONS MAY BE POSSIBLE OVER
EASTERN NORTH DAKOTA AFTER MID EVENING. EXPECT NORTH WIND OF 20 TO
30 MPH WITH HIGHER GUST FOR TODAY.
&&
.FGF WATCHES/WARNINGS/ADVISORIES...
ND...WINTER WEATHER ADVISORY UNTIL MIDNIGHT CST TONIGHT FOR NDZ014-
015-024-026>030-038-039-049-052-053.
BLIZZARD WARNING UNTIL 6 PM CST THIS EVENING FOR NDZ006>008-016-
054.
MN...WINTER WEATHER ADVISORY UNTIL MIDNIGHT CST TONIGHT FOR
MNZ001>003-005-006-008-009-013>017-022>024-027>032-040.
BLIZZARD WARNING UNTIL 6 PM CST THIS EVENING FOR MNZ004-007.
&&
$$
UPDATE...TG
SHORT TERM...HOPPES
LONG TERM...DK
AVIATION...HOPPES