Forecast Discussions mentioning any of
"HRRR" "RAP" "RR" "RUC13" "RUC" received at GSD on 12/12/13
AREA FORECAST DISCUSSION
NWS DENVER/BOULDER CO
341 PM MST TUE DEC 10 2013
.SHORT TERM...WINDS STILL QUITE GUSTY IN AND NEAR FOOTHILLS...
BEGINNING TO SHOW SOME DECREASE AS PRESSURE GRADIENT FROM GJT TO
DEN DECREASES AND WEAK LIFT FROM APPROACHING WAVE BEGINS TO OFFSET
THE DOWNWARD MOTION. CROSS MOUNTAIN FLOW AVERAGED AROUND 50 KTS
ACROSS THE NORTHERN FOOTHILLS FOR MUCH OF THE AFTERNOON...BASED ON
THE RAP ALONG WITH THE PERSISTENT MOUNTAIN WAVE. THE PRESSURE
GRADIENT FROM GJT TO DEN DID PEAK AT 15.16 MB AT 17Z. DID RECEIVE
A GUST TO 83 MPH AT LYONS AT 115 PM...APPEARS THIS STRONG WIND
GUST WAS CHANNELED ACROSS THIS AREA AND RATHER LOCALIZED. OTHER
GUSTS ALONG THE FOOTHILLS NOT NEARLY THAT STRONG...GENERALLY
AROUND 60 MPH. THE GUSTY DOWNSLOPE WINDS DID INCREASE TEMPERATURES
ACROSS THE URBAN CORRIDOR. STILL THINKING THE WINDS WILL BE ON
THE DECREASE BY THE EVENING ONCE THE AIRMASS STABILIZES AND
MOUNTAIN WAVE WEAKENS. SHORT TERM MODELS SHOW THE GJT TO DEN
PRESSURE GRADIENT DECREASING THROUGH THE EVENING... WITH THE CROSS
MOUNTAIN FLOW DECREASING TO AROUND 40 KTS NEAR MOUNTAIN TOP. MAY
STILL BE A BIT GUSTY IN AND NEAR THE FOOTHILLS. MOISTURE NOW
SPREADING INTO NORTHERN MOUNTAINS AS THE MID LEVEL DISTURBANCE
MOVES ACROSS WYOMING. WEAK MID LEVEL ASCENT AND OROGRAPHICS WITH
NORTHWEST FLOW ALOFT ENOUGH TO KEEP A CHANCE OF LIGHT SNOW FOR THE
NORTHERN MOUNTAINS. SNOW CHANCES DECREASE ACROSS CENTRAL
MOUNTAINS. LATEST MODEL QPF HAD DECREASED THE AMOUNT OF PRECIP AND
THUS SNOW AMOUNTS. SO ANY ACCUMULATIONS TO BE AROUND AN INCH OR
LESS... MAINLY ACROSS ZONE 31. ACROSS THE PLAINS...WEAK SURGE
STILL EXPECTED TO MOVE INTO THE AREA AROUND MIDNIGHT...DROPPING
TEMPERATURES BACK INTO THE SINGLE DIGITS DESPITE THE NICE WARMUP
THIS AFTERNOON. WINDS WILL BE WEAKENING DURING THE EVENING...AND
MAY BECOME EASTERLY FOR A SHORT TIME BEFORE GOING TO DRAINAGE
AROUND MIDNIGHT. CROSS SECTIONS DO NOT SHOW ANY LOW LEVEL MOISTURE
SO DO NOT THINK FOG OR LOW STRATUS WILL DEVELOP. MAY BE SOME MID
LEVEL CLOUD DURING THE EVENING. ON WEDNESDAY...THE NORTHWEST FLOW
ALOFT WILL CONTINUE THOUGH NOT AS STRONG AS TODAY. NAM CROSS
SECTIONS SHOWING CROSS MOUNTAIN FLOW AROUND 25-30 KTS. MAY SEE
SOME GUSTS AROUND 40 MPH OVER THE MOUNTAINS AND HIGHER FOOTHILLS.
ACROSS PLAINS...COOLER AIRMASS WILL BE IN PLACE...WITH HIGHS ONLY
IN THE LOWER 30S. ACTUALLY ABOUT 10 TO 15 DEGREES COOLER ALONG THE
URBAN CORRIDOR. AIRMASS WILL BE DRY WITH NO PRECIPITATION
EXPECTED. JUST SOME HIGH LEVEL MOISTURE DURING THE AFTERNOON.
.LONG TERM...THE FLOW ALOFT WILL REMAIN NORTHWESTERLY WEDNESDAY NIGHT
WITH AN UPPER RIDGE TO THE NORTHWEST AND A WEAK TROUGH OFF THE SRN
CA/BAJA COAST. THURSDAY INTO THURSDAY NIGHT...WEAK UPWARD ASCENT
WILL DEVELOP...AS THE CLOSED UPPER LOW SHIFT TO THE NORTH AND EAST.
THE MDLS EVENTUALLY MOVE THIS SYSTEM ACROSS SRN CO/NRN NEW MX LATE
THURSDAY NIGHT INTO FRIDAY...WITH A WEAK SECONDARY SYSTEM DROPPING
FM THE PAC NORTHWEST AND PASSING ACROSS WRN AND SRN CO LATE FRIDAY
INTO FRIDAY NIGHT. SINCE BOTH OF THESE SYSTEMS ARE WEAK AND
GENERALLY PASSING TO THE WEST AND SOUTH OF THE CWFA...WL GO WITH
NO MORE THAN A CHANCE OF SNOW IN THE HIGH COUNTRY. THE BEST CHANCE
OF SNOW IN THE NRN MOUNTAINS APPEARS TO BE FRIDAY NIGHT...WITH THE
PASSAGE OF THE SECOND SYSTEM. ACROSS THE PLAINS...IT WILL REMAIN
DRY THROUGH THE PERIOD. IT WILL WARM INTO THURSDAY...WITH SLIGHTLY
COOLER TEMPERATURES (BUT STILL NEAR NORMAL) ON FRIDAY AND
SATURDAY...WITH TEMPERATURES EXPECTED WARM UP AGAIN SUNDAY AND
MONDAY. A LEE SIDE SURFACE TROUGH WILL DEVELOP OVER EASTERN CO
THURSDAY AFTN...WITH A WEAK FROPA FRIDAY AFTN. SUNDAY INTO
MONDAY...A BROAD UPPER RIDGE OVER THE WEST COAST WILL PRODUCE AND
DRY AND SUBSIDENT NORTHWESTERLY FLOW ALOFT OVER CO.
&&
.AVIATION...WINDS TRENDING MORE NORTHWEST...WITH SOME DECREASE IN
SPEEDS. GUSTS STILL AROUND 30 KTS AT KBJC WITH A FEW GUSTS AROUND
20 KTS AT KDEN. GRADIENT EXPECTED TO WEAKEN THIS EVENING...
SHOULD SEE WINDS DECREASE AS A RESULT. A WEAK SURGE WILL BE MOVING
IN FROM THE NORTH AROUND MIDNIGHT. WINDS MAY GO NORTHEAST AROUND
03Z AND EAST TO SOUTHEAST BY 06Z AS SHOWN BY THE LATEST MODELS.
BUT WILL BE FIGHTING THE WEAKENING WEST TO EAST GRADIENT. CURRENT
THINKING IS THAT THE SOUTHERLY DRAINAGE FLOW WILL PREVAIL BY 03Z
AND CONTINUE THROUGH THE MORNING HOURS WEDNESDAY. BY 18Z WINDS TO
BECOME SHIFT TO THE SOUTHEAST...SPEEDS TO STAY BELOW 8 KTS. VFR TO
CONTINUE WITH UNLIMITED CEILINGS. LOWER AIRMASS WILL BE DRY SO NOT
EXPECTING LOW CLOUDS OR FOG OVERNIGHT.
&&
.BOU WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...D-L
LONG TERM....COOPER
AVIATION...D-L
AREA FORECAST DISCUSSION
NWS DENVER/BOULDER CO
123 PM MST TUE DEC 10 2013
.UPDATE...
&&
.SHORT TERM...CHINOOK WINDS HAVE WARMED TEMPERATURES ACROSS THE
URBAN CORRIDOR AND ADJACENT PLAINS INTO THE 40S. ALSO...WINDS
STILL GUSTY THOUGH DECREASING TRENDS STILL LOOKS REASONABLE BY
THIS EVENING. TEMPERATURE AND WIND GRIDS UPDATED TO REFLECT
CURRENT CONDITIONS.
.PREV DISCUSSION... /ISSUED 955 AM MST TUE DEC 10 2013/
UPDATE...
SHORT TERM...BRISK NORTHWEST FLOW ALOFT STILL PRODUCING AMPLIFIED
MOUNTAIN WAVE OVER NORTHERN COLORADO. WINDS FAIRLY GUSTY OVER
MOUNTAIN RIDGES AND EASTERN SLOPES WITH SOME GUSTS AROUND 50 MPH
OBSERVED ALONG THE FOOTHILLS OF NORTHERN JEFFERSON AND SOUTHERN
BOULDER COUNTIES. SOME SIGNS OF THE MOUNTAIN WAVE ON THE DECREASE
WITH WEAKENING MOUNTAIN TOP INVERSION...DUE TO WEAK ASCENT
BEGINNING TO MOVE INTO STATE AHEAD OF A MID LEVEL DISTURBANCE.
SHOULD CONTINUE TO SEE SOME DECREASE IN WINDS THROUGH THE
AFTERNOON...LATEST RAP INDICATING CROSS MOUNTAIN FLOW DECREASING.
THIS TREND NOTED IN LATEST GRIDS...LOOKS REASONABLE. DID INCLUDE
LOCAL BLOWING SNOW EARLY THIS AFTERNOON OVER THE HIGHER FOOTHILLS.
ALSO MADE SOME ADJUSTMENTS TO CLOUD COVER DUE TO CURRENT TRENDS.
REST OF FORECAST SEEMS REASONABLE. SOME INCREASE IN MOISTURE
ACROSS MOUNTAINS LATER TODAY WITH A CHANCE OF SNOW NORTHERN
MOUNTAINS BY THIS EVENING. SNOW AMOUNTS TO BE LESS THAN 2 INCHES.
&&
.AVIATION...WESTERLY WINDS SPREADING ACROSS AREA...WITH GUSTS TO
35 KTS AT KBJC. WINDS LESS FURTHER EAST...THOUGH SOME GUSTS
AROUND 20 KTS SPREADING ACROSS KDEN. WINDS WILL BE DECREASING BY
21Z...TRENDING A BIT MORE NORTHWEST AT KDEN AND KAPA. DRAINAGE
WINDS THEN EXPECTED BY 02Z. WILL CONTINUE CURRENT TAF TRENDS FOR
THE UPCOMING ISSUANCE. VFR CONDITIONS TO PREVAIL WITH UNLIMITED
CEILINGS.
.PREV DISCUSSION... /ISSUED 359 AM MST TUE DEC 10 2013/
SHORT TERM...NORTHWESTERLY FLOW ALOFT WILL CONTINUE OVER COLORADO
TODAY AND TONIGHT AS A STRONG UPPER RIDGE AXIS REMAINS ANCHORED
JUST OFFSHORE FROM THE PACIFIC NORTHWEST. THE AIRMASS OVER THE
FORECAST AREA IS STARTING OUT VERY DRY...BUT MID-LEVEL MOISTURE
WILL BE INCREASING OVER THE MOUNTAINS BY THIS AFTERNOON. SOME
PARTS OF NORTHWEST COLORADO ARE ALREADY SEEING A MID-LEVEL CLOUD
DECK MOVE OVERHEAD AT THE PRESENT TIME. AS THE MOISTURE
INCREASES...THE CHANCE OF SNOW WILL RETURN TO THE MOUNTAIN AREAS
OF NORTH-CENTRAL COLORADO. MODEL QPF FIELDS ONLY SHOW LIGHT
AMOUNTS OF SNOW FROM THIS SHOT OF MOISTURE. IT ALSO APPEARS THAT
IT WILL ONLY SNOW FOR ABOUT 6-12 HOURS. SNOW ACCUMULATIONS SHOULD
BE LESS THAN 1 OR 2 INCHES.
AHEAD OF THE APPROACHING MOISTURE...GUSTY WINDS HAVE BEEN BLOWING
OVER THE MOUNTAIN RIDGES AND EASTERN SLOPES. GUSTS UP TO 60 MPH
HAVE BEEN OBSERVED AT A FEW LOCATIONS. HOWEVER...THE WINDS HAVE
BEEN QUITE LOCALIZED AND NOT STRONG ENOUGH TO WARRANT ANY
HIGHLIGHT. THE FORECAST WILL MENTION PATCHY BLOWING SNOW BECAUSE
OF THE WINDS. THE AMPLIFIED MOUNTAIN WAVE THAT IS DRIVING THE
GUSTY WINDS LOOKS LIKE IT WILL BEGIN WEAKENING AFTER 11 AM WITH
GRADUALLY DIMINISHING WINDS THROUGH THE AFTERNOON HOURS. THE
ARRIVAL OF INCREASING MOISTURE DURING THE AFTERNOON MAY ALSO HELP
ALTER THE MOUNTAIN WAVE AND DECREASE THE WINDS SOONER.
THE OTHER FEATURE OF THE FORECAST IS TEMPERATURES ON THE PLAINS
CLIMBING ABOVE THE FREEZING MARK FOR THE FIRST TIME IN A WEEK...IF
ONLY BY A FEW DEGREES AND PRIMARILY SOUTH OF I-76. TEMPERATURES
TO THE NORTH OF I-76 ARE ONLY EXPECTED TO MAKE IT TO ABOUT 30
DEGREES. TEMPERATURES TONIGHT WILL DROP BACK TO THE SINGLE DIGITS
AS A WEAK SURGE OF COOLER AIR MOVES IN FROM THE NORTH.
LONG TERM...NW FLOW ALOFT WILL BE OVER THE AREA ON WED AND THEN
BECOME MORE WLY BY THU. CROSS-SECTIONS SHOW ANY MOISTURE WILL BE
ABV 500 MB SO WILL KEEP A DRY FCST IN PLACE BOTH DAYS ALTHOUGH
THERE MAYBE SOME WAVE CLOUDS FROM TIME TO TIME. TEMPS WILL
CONTINUE TO MODERATE SLOWLY WITH READINGS OVER NERN CO RANGING
FROM THE MID 20S TO LOWER 30S ACROSS THE PLAINS WHILE AREAS AROUND
DENVER RISE INTO THE MID TO UPPER 30S. BY THU READINGS SHOULD RISE
BACK INTO THE LOWER TO MID 40S OVER MOST OF NERN CO. WINDS WILL
CONTINUE GUSTY IN THE MTNS AND FOOTHILLS BOTH DAYS BUT SPEEDS
SHOULD STAY BLO HIGH WIND CRITERIA.
BY FRI A WK UPPER LEVEL TROUGH WILL MOVE ACROSS THE AREA IN NW FLOW
ALOFT. CROSS-SECTIONS SHOW ENOUGH MOISTURE FOR A CHC OF SNOW
SHOWERS IN THE MTNS. OVER NERN CO A COOL FNT WILL AFFECT THE NERN
PLAINS BY AFTN AND THEN BACKDOOR INTO THE FRONT RANGE BY EARLY FRI
EVENING. THERE COULD BE A SLIGHT CHC OF SNOW SHOWERS OVER NERN
CORNER FRI EVENING AS THE WK UPPER LEVEL TROUGH MOVES ACROSS. AS
FOR HIGHS WILL KEEP READINGS IN THE LOWER TO MID 40S OVER NERN CO
HOWEVER IF FNT COMES IN FASTER THEN HIGHS COULD END UP BEING COOLER.
FOR SAT AND SUN BRISK NW FLOW ALOFT WILL BE OVER THE AREA WITH SOME
MOISTURE AFFECTING THE MTNS. APPEARS A WK DISTURBANCE COULD LEAD TO
A BETTER CHC OF SNOW SHOWERS ON SUN. OVER NERN CO OUTSIDE OF SOME
MID AND HIGH CLOUDS IT LOOKS DRY BOTH DAYS. HIGHS ON SAT MAY DROP
BACK INTO THE UPPER 30S TO LOWER 40S OVER NERN CO BUT THEN REBOUND
BACK INTO THE 40S ON SUN. BY MON LITTLE CHANGE WILL OCCUR AS NW
FLOW ALOFT REMAINS OVER THE AREA. MOISTURE DECREASES ON MON IN THE
MTNS SO WILL ONLY MENTION A SLIGHT CHC OF SNOW. OVER NERN CO IT
WILL BE DRY WITH HIGHS RISING INTO THE MID 40S TO NEAR 50.
AVIATION...CEILINGS AND VISIBILITIES WILL REMAIN UNRESTRICTED
THROUGH TODAY AND TONIGHT WITH NO PRECIPITATION EXPECTED. PERIODS
OF WEST WINDS...GUSTING TO 30-35 MPH...WILL CONTINUE THIS MORNING
NEAR THE FOOTHILLS AND AS FAR EAST AS KBJC...BUT ARE NOT EXPECTED
TO AFFECT KDEN OR KAPA. WINDS WILL BE DIMINISHING THROUGH THE
AFTERNOON HOURS. TYPICAL DRAINAGE WINDS ARE EXPECTED OVERNIGHT
TONIGHT.
&&
.BOU WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...D-L
LONG TERM....RPK
AREA FORECAST DISCUSSION
NWS DENVER/BOULDER CO
955 AM MST TUE DEC 10 2013
.UPDATE...
&&
.SHORT TERM...BRISK NORTHWEST FLOW ALOFT STILL PRODUCING AMPLIFIED
MOUNTAIN WAVE OVER NORTHERN COLORADO. WINDS FAIRLY GUSTY OVER
MOUNTAIN RIDGES AND EASTERN SLOPES WITH SOME GUSTS AROUND 50 MPH
OBSERVED ALONG THE FOOTHILLS OF NORTHERN JEFFERSON AND SOUTHERN
BOULDER COUNTIES. SOME SIGNS OF THE MOUNTAIN WAVE ON THE DECREASE
WITH WEAKENING MOUNTAIN TOP INVERSION...DUE TO WEAK ASCENT
BEGINNING TO MOVE INTO STATE AHEAD OF A MID LEVEL DISTURBANCE.
SHOULD CONTINUE TO SEE SOME DECREASE IN WINDS THROUGH THE
AFTERNOON...LATEST RAP INDICATING CROSS MOUNTAIN FLOW DECREASING.
THIS TREND NOTED IN LATEST GRIDS...LOOKS REASONABLE. DID INCLUDE
LOCAL BLOWING SNOW EARLY THIS AFTERNOON OVER THE HIGHER FOOTHILLS.
ALSO MADE SOME ADJUSTMENTS TO CLOUD COVER DUE TO CURRENT TRENDS.
REST OF FORECAST SEEMS REASONABLE. SOME INCREASE IN MOISTURE
ACROSS MOUNTAINS LATER TODAY WITH A CHANCE OF SNOW NORTHERN
MOUNTAINS BY THIS EVENING. SNOW AMOUNTS TO BE LESS THAN 2 INCHES.
.AVIATION...WESTERLY WINDS SPREADING ACROSS AREA...WITH GUSTS TO
35 KTS AT KBJC. WINDS LESS FURTHER EAST...THOUGH SOME GUSTS
AROUND 20 KTS SPREADING ACROSS KDEN. WINDS WILL BE DECREASING BY
21Z...TRENDING A BIT MORE NORTHWEST AT KDEN AND KAPA. DRAINAGE
WINDS THEN EXPECTED BY 02Z. WILL CONTINUE CURRENT TAF TRENDS FOR
THE UPCOMING ISSUANCE. VFR CONDITIONS TO PREVAIL WITH UNLIMITED
CEILINGS.
&&
.PREV DISCUSSION... /ISSUED 359 AM MST TUE DEC 10 2013/
SHORT TERM...NORTHWESTERLY FLOW ALOFT WILL CONTINUE OVER COLORADO
TODAY AND TONIGHT AS A STRONG UPPER RIDGE AXIS REMAINS ANCHORED
JUST OFFSHORE FROM THE PACIFIC NORTHWEST. THE AIRMASS OVER THE
FORECAST AREA IS STARTING OUT VERY DRY...BUT MID-LEVEL MOISTURE
WILL BE INCREASING OVER THE MOUNTAINS BY THIS AFTERNOON. SOME
PARTS OF NORTHWEST COLORADO ARE ALREADY SEEING A MID-LEVEL CLOUD
DECK MOVE OVERHEAD AT THE PRESENT TIME. AS THE MOISTURE
INCREASES...THE CHANCE OF SNOW WILL RETURN TO THE MOUNTAIN AREAS
OF NORTH-CENTRAL COLORADO. MODEL QPF FIELDS ONLY SHOW LIGHT
AMOUNTS OF SNOW FROM THIS SHOT OF MOISTURE. IT ALSO APPEARS THAT
IT WILL ONLY SNOW FOR ABOUT 6-12 HOURS. SNOW ACCUMULATIONS SHOULD
BE LESS THAN 1 OR 2 INCHES.
AHEAD OF THE APPROACHING MOISTURE...GUSTY WINDS HAVE BEEN BLOWING
OVER THE MOUNTAIN RIDGES AND EASTERN SLOPES. GUSTS UP TO 60 MPH
HAVE BEEN OBSERVED AT A FEW LOCATIONS. HOWEVER...THE WINDS HAVE
BEEN QUITE LOCALIZED AND NOT STRONG ENOUGH TO WARRANT ANY
HIGHLIGHT. THE FORECAST WILL MENTION PATCHY BLOWING SNOW BECAUSE
OF THE WINDS. THE AMPLIFIED MOUNTAIN WAVE THAT IS DRIVING THE
GUSTY WINDS LOOKS LIKE IT WILL BEGIN WEAKENING AFTER 11 AM WITH
GRADUALLY DIMINISHING WINDS THROUGH THE AFTERNOON HOURS. THE
ARRIVAL OF INCREASING MOISTURE DURING THE AFTERNOON MAY ALSO HELP
ALTER THE MOUNTAIN WAVE AND DECREASE THE WINDS SOONER.
THE OTHER FEATURE OF THE FORECAST IS TEMPERATURES ON THE PLAINS
CLIMBING ABOVE THE FREEZING MARK FOR THE FIRST TIME IN A WEEK...IF
ONLY BY A FEW DEGREES AND PRIMARILY SOUTH OF I-76. TEMPERATURES
TO THE NORTH OF I-76 ARE ONLY EXPECTED TO MAKE IT TO ABOUT 30
DEGREES. TEMPERATURES TONIGHT WILL DROP BACK TO THE SINGLE DIGITS
AS A WEAK SURGE OF COOLER AIR MOVES IN FROM THE NORTH.
LONG TERM...NW FLOW ALOFT WILL BE OVER THE AREA ON WED AND THEN
BECOME MORE WLY BY THU. CROSS-SECTIONS SHOW ANY MOISTURE WILL BE
ABV 500 MB SO WILL KEEP A DRY FCST IN PLACE BOTH DAYS ALTHOUGH
THERE MAYBE SOME WAVE CLOUDS FROM TIME TO TIME. TEMPS WILL
CONTINUE TO MODERATE SLOWLY WITH READINGS OVER NERN CO RANGING
FROM THE MID 20S TO LOWER 30S ACROSS THE PLAINS WHILE AREAS AROUND
DENVER RISE INTO THE MID TO UPPER 30S. BY THU READINGS SHOULD RISE
BACK INTO THE LOWER TO MID 40S OVER MOST OF NERN CO. WINDS WILL
CONTINUE GUSTY IN THE MTNS AND FOOTHILLS BOTH DAYS BUT SPEEDS
SHOULD STAY BLO HIGH WIND CRITERIA.
BY FRI A WK UPPER LEVEL TROUGH WILL MOVE ACROSS THE AREA IN NW FLOW
ALOFT. CROSS-SECTIONS SHOW ENOUGH MOISTURE FOR A CHC OF SNOW
SHOWERS IN THE MTNS. OVER NERN CO A COOL FNT WILL AFFECT THE NERN
PLAINS BY AFTN AND THEN BACKDOOR INTO THE FRONT RANGE BY EARLY FRI
EVENING. THERE COULD BE A SLIGHT CHC OF SNOW SHOWERS OVER NERN
CORNER FRI EVENING AS THE WK UPPER LEVEL TROUGH MOVES ACROSS. AS
FOR HIGHS WILL KEEP READINGS IN THE LOWER TO MID 40S OVER NERN CO
HOWEVER IF FNT COMES IN FASTER THEN HIGHS COULD END UP BEING COOLER.
FOR SAT AND SUN BRISK NW FLOW ALOFT WILL BE OVER THE AREA WITH SOME
MOISTURE AFFECTING THE MTNS. APPEARS A WK DISTURBANCE COULD LEAD TO
A BETTER CHC OF SNOW SHOWERS ON SUN. OVER NERN CO OUTSIDE OF SOME
MID AND HIGH CLOUDS IT LOOKS DRY BOTH DAYS. HIGHS ON SAT MAY DROP
BACK INTO THE UPPER 30S TO LOWER 40S OVER NERN CO BUT THEN REBOUND
BACK INTO THE 40S ON SUN. BY MON LITTLE CHANGE WILL OCCUR AS NW
FLOW ALOFT REMAINS OVER THE AREA. MOISTURE DECREASES ON MON IN THE
MTNS SO WILL ONLY MENTION A SLIGHT CHC OF SNOW. OVER NERN CO IT
WILL BE DRY WITH HIGHS RISING INTO THE MID 40S TO NEAR 50.
AVIATION...CEILINGS AND VISIBILITIES WILL REMAIN UNRESTRICTED
THROUGH TODAY AND TONIGHT WITH NO PRECIPITATION EXPECTED. PERIODS
OF WEST WINDS...GUSTING TO 30-35 MPH...WILL CONTINUE THIS MORNING
NEAR THE FOOTHILLS AND AS FAR EAST AS KBJC...BUT ARE NOT EXPECTED
TO AFFECT KDEN OR KAPA. WINDS WILL BE DIMINISHING THROUGH THE
AFTERNOON HOURS. TYPICAL DRAINAGE WINDS ARE EXPECTED OVERNIGHT
TONIGHT.
&&
.BOU WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...D-L
LONG TERM....RPK
AVIATION...D-L
AREA FORECAST DISCUSSION
NWS DENVER/BOULDER CO
913 PM MST MON DEC 9 2013
.UPDATE...
&&
.SHORT TERM...GUSTY WINDS CONTINUE IN/BASE OF THE FOOTHILLS THIS
EVENING BUT THERE HAS BEEN A DECREASING TREND DURING THE PAST 2
HOURS. STRONGEST SUBSIDENCE HAS MOVED AWAY WHICH HELPED TO
ENHANCE THE STRONGER WINDS EARLIER THIS EVENING. CROSS SECTIONS
SHOWING STRONGEST WINDS WILL RECEED INTO THE HIGHER FOOTHILLS
OVERNIGHT. STILL COULD BE SOME GUSTY WINDS IN THE 40-60 MPH RANGE
BUT STILL DON`T THINK IT WILL BE A WIDESPREAD HIGH WIND EVENT.
WITH THESE UPDATES HAVE INCREASED WINDS AND TRENDS FOR THE REST OF
TONIGHT AND FOR HIGHER WINDS IN THE MOUNTAINS ON TUESDAY. SURFACE
GRADIENT WILL RELAX TUESDAY AFTERNOON AS WEAK FRONT WILL DIMINISH
THE GRADIENT ACROSS THE STATE.
.AVIATION...STILL QUITE WINDY AT BJC AND WILL EXTEND THE STRONG
WEST WINDS THROUGH ABOUT 08Z AND THEN DECREASE A BIT. WINDS AT DEN
WILL CONTINUE TO DECREAE AND SHIFT MORE SOUTHWEST OVERNIGHT THOUGH
THERE COULD BE AN OCCASIONAL PUFF OF WEST WINDS DURING THE NIGHT.
WEAK SURFACE FRONT WILLL MOVE ACROSS TERMINALS LATE TUE AFTERNOON
AS WINDS SHIFT NORTH AND NORTHEAST.
&&
.PREV DISCUSSION... /ISSUED 625 PM MST MON DEC 9 2013/
UPDATE...
SHORT TERM...STRONG AND GUSTY WINDS HAVE DEVELOPED IN THE LOWER
AND BASE OF FOOTHILLS WITH A FEW LOCALIZED HIGH WIND GUSTS BETWEEN
GOLDEN AND BOULDER. MOST OTHER AREAS ARE MUCH LOWER...GENERALLY IN
THE 30-50 MPH RANGE. BEING SO LOCALIZED WILL NOT ISSUE A HIGH WIND
WARNING FOR NOW. GOOD MOUNTAIN WAVE SET UP AS 00Z DENVER SOUNDING
SHOWED STRONG INVERSION AT 700MB WHILE SURFACE GRADIENT AROUND
12MB ACROSS THE STATE. QG FIELDS ALSO SHOWING VERY STRONG
SUBSIDENCE AS RAP SHOWED +50 ON THE QG VERTICAL VELOCITY FIELDS
AT 500MB. WILL WATCH THIS CLOSELY THIS EVENING IN CASE
OBSERVATIONS SHOW THE STRONGER WINDS BECOME MORE WIDESPREAD.
AVIATION...GUSTY WEST WINDS HAVE NOW SURFACED AT KDEN AND HAVE
ADDED STRONGER WINDS AT THE TERMINAL UNTIL 03Z. EXPECT GUSTY WINDS
TO CONTINUE AT BJC IN THE 25-40KT RANGE. WINDS WILL GRADUALLY
DECREASE IN BOTH LOCATIONS LATER THIS EVENING.
PREV DISCUSSION... /ISSUED 338 PM MST MON DEC 9 2013/
SHORT TERM...SUBSIDENCE BEHIND THIS MORNING`S WEAK TROUGH
COMBINED WITH INCREASING PRESSURE GRADIENT FROM GJT TO DEN AND
MIXING TO PRODUCE GUSTY WINDS ACROSS MOUNTAINS AS WELL AS IN AND
NEAR FOOTHILLS. LATEST RAP ANALYSIS SHOWING THE MAIN BATCH OF
SUBSIDENCE NOW MOVING OVERHEAD. MOST GUSTS WERE AROUND 40
MPH...THOUGH THERE WERE GUSTS AROUND 55 MPH IN WIND PRONE AREAS IN
THE FOOTHILLS OF NORTHERN JEFFERSON COUNTY. WINDS WERE LESS
FURTHER AWAY FROM THE FOOTHILLS. THE GUSTY WINDS WERE PRODUCING
SOME BLOWING SNOW...CONFINED TO OPEN AREAS. THE GUSTY WINDS WILL
PERSIST INTO THE EVENING THEN RETREAT INTO THE HIGHER FOOTHILLS BY
MIDNIGHT AS MIXING AND SUBSIDENCE WEAKENS. BUT THESE WINDS SHOULD
ALSO STRENGTHEN AS CROSS MOUNTAIN FLOW INCREASES TO AROUND 40 KTS.
THIS COULD RESULT IN GUSTS AROUND 65 MPH IN WIND PRONE AREAS. NOT
EXPECTING THE GUSTS REACHING HIGH WIND CRITERIA OF 75 MPH AT THIS
TIME. SOME BLOWING SNOW WILL BE POSSIBLE...ESPECIALLY IN OPEN
AREAS. A BIT OF MOISTURE STILL TRAPPED ACROSS THE MOUNTAIN AND
THERE MAY BE A FEW LIGHT SNOW SHOWERS OR FLURRIES. OVERNIGHT
TEMPERATURES EXPECTED TO FALL INTO THE SINGLE DIGITS ACROSS THE
PLAINS WITH BELOW ZERO READINGS IN THE HIGH COUNTRY AND LOW LYING
AREAS NEAR LIMON AND GREELEY. TEMPERATURES TO BE WARMER IN AND
NEAR FOOTHILLS DUE TO THE DOWNSLOPE WINDS. ON TUESDAY...NORTHWEST
FLOW ALOFT TO PREVAIL. THERE WILL BE SOME WARMING DUE TO UPPER
LEVEL RIDGE BUILDING ACROSS THE GREAT BASIN AND DOWNSLOPE WINDS
ALONG FOOTHILLS. TEMPERATURES ACROSS THE PLAINS TO WARM INTO THE
LOWER 30S...WITH UPPER 20S IN THE LOW LYING AREAS. MOUNTAIN AREAS
SHOULD WARM INTO THE TEENS BUT GUSTY WINDS WILL KEEP WIND CHILL
READINGS BELOW ZERO. GUIDANCE VALUES STILL A BIT OPTIMISTIC WITH
THE WARMUP. SOME MOISTURE AND WEAK LIFT MOVES INTO THE NORTHERN
MOUNTAINS...ENOUGH FOR A SLIGHT CHANCE OF LIGHT SNOW. ANY
ACCUMULATIONS TO BE MINIMAL.
LONG TERM...WEATHER THE NEXT WEEK WILL BE DOMINATED BY A RIDGE
OVER COLORADO. WEAK RIPPLES COMING NORTH OF US IN WESTERLY FLOW
AND A WEAK LOW PASSING WELL SOUTH OF US. ALL OF THESE THINGS
CONTINUE TO GET WEAKER WITH SUBSEQUENT MODEL RUNS AND SHOULD NOT
HAVE MUCH EFFECT ON OUR WEATHER. THERE WILL BE A CHANCE OF LIGHT
SNOW IN THE MOUNTAINS WITH THE TAIL END OF THE NORTHERN SHORT
WAVES...AND WEAK SURGES OF COOL AIR FROM THE NORTH AS WELL. THESE
WILL COME ABOUT FRIDAY AND AGAIN ON SUNDAY OR MONDAY...BRINGING
A LITTLE COOLING...OR DELAYING THE WARMING...EACH DAY. BY THE END
OF THE WEEK THE AIR ALOFT WILL BE QUITE WARM...BUT THE LOW LEVELS
WILL LAG BEHIND. ALL OF THIS IS WELL COVERED IN THE CURRENT
FORECAST AND THE MODEL CONSENSUS LOOKS GOOD.
AVIATION...WESTERLY WINDS HAVE PUSHED ACROSS THE AREA
AIRPORTS WITH GUSTS AROUND 35 KTS AT KBJC. WINDS MUCH LESS AT KDEN
AND KAPA...AROUND 12 KTS. WINDS AT KDEN AND KAPA WILL TRANSITION
TO DRAINAGE BY 02Z...REMAINING WESTERLY AT KBJC. SOME GUSTS COULD
AGAIN REACH 35 KTS AT KBJC OVERNIGHT. ON TUESDAY...WINDS WILL
WEAKEN AND BECOME NORTHWEST BY 17Z...SPEEDS AROUND 8 KTS. VFR TO
CONTINUE WITH UNLIMITED CEILINGS.
&&
.BOU WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...ENTREKIN
LONG TERM....GIMMESTAD
AVIATION...ENTREKIN
AREA FORECAST DISCUSSION
NWS TAUNTON MA
1025 AM EST TUE DEC 10 2013
.SYNOPSIS...
LOW PRESSURE TRACKING SOUTH OF NEW ENGLAND TODAY WILL SPREAD
ACCUMULATING SNOWS TO CONNECTICUT... RHODE ISLAND AND SOUTHEAST
MASSACHUSETTS LATER THIS MORNING AND AFTERNOON. AN ARCTIC AIRMASS
OVER SPREADS SOUTHERN NEW ENGLAND WEDNESDAY NIGHT INTO FRIDAY. A
LOW PRESSURE SYSTEM WILL LIKELY BRING A WINTRY MIX OF
PRECIPITATION THIS WEEKEND.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
1030 AM UPDATE...
OVERALL THINKING OF THE FORECAST REMAINS ON TRACK FOR THIS MORNING
AND THE AFTERNOON HOURS. SNOW HAS OVERSPREAD ACROSS MUCH OF THE
REGION THIS MORNING...STAYING SOUTH OF THE ROUTE 2. LATEST
SOUNDINGS AT CHH AND GYX SHOW A GOOD AMOUNT OF DRY AIR AT 800 MB.
BELIEVE THAT IT MAKE TAKE A BIT FOR THE COLUMN TO MOISTEN UP
NORTH OF ROUTE 2. HOWEVER ONCE WHEN COLUMN IS SATURATED BELIEVE
FLURRIES/LIGHT SNOW WILL FALL.
RADAR SHOWING 2 BANDS MOVING ACROSS THE REGION AT THIS TIME. THE
FIRST ONCE IS ACROSS HFD TO ORH WHILE THE SECOND MORE PRONOUNCED
ONE IS ACROSS SOUTHERN CT INTO SOUTHERN RI AND STARTING TO MOVE
INTO FMH. BOTH OF THESE BANDS WILL REDUCE VISIBILITIES AND
INCREASE THE SNOWFALL RATES CLOSE TO AN INCH PER HOUR.
AS MENTIONED BY PREV FORECASTER THIS IS A QUICK MOVING SYSTEM SO
BELIEVE THAT FROM NOW TIL AROUND 3-4PM WILL BE THE BEST TIMEFRAME
FOR SNOW TO ACCUMULATE. MODELS INDICATE THAT SNOW WILL BE
LIGHTENING UP AND TAPERING OFF JUST AS THE EVENING COMMUTE GETS
GOING. SNOW MAY LINGERING ACROSS THE CAPE TIL ABOUT 00Z. BECAUSE
TEMPS ARE FALLING BELOW FREEZING THROUGHOUT THE DAY...ANY
UNTREATED ROADS WILL BE SLIPPERY.
BELIEVE THAT SOUTH OF THE PIKE HAS THE BEST CHANCE OF SEEING ANY
ACCUMULATIONS...WHERE THE HIGHER ACCUMS WILL BE ACROSS CT...RI AND
SE MASS OF 1-3 INCHES. MAIN CONCERN IS THE AMOUNT OF BANDING
ACROSS THE IMMEDIATE SOUTH SHORE. THE LATEST NAM AND HRRR MODELS
CONTINUE TO KEEP THE HIGHER QPF AMOUNTS HUGGING THE SOUTH COAST.
HOWEVER THERE CONTINUES TO BE EXCELLENT MOISTURE IN THE SNOW
GROWTH REGION WHERE A STRONG DEFORMATION ZONE MAY DEVELOP. WE WILL
NEED TO WATCH THE LATEST RADAR TRENDS TO MONITOR FOR THIS BANDING
POTENTIAL. IF THIS DOES OCCUR...THE BEST LOCATION WILL BE ALONG
THE SOUTH COAST...WHICH MAY INCREASE THE SNOWFALL A FEW MORE
INCHES WITH SNOWFALL RATES NEARING OVER AN INCH AN HOUR.
DAYTIME HIGHS WILL GENERALLY BE IN THE 30S...THOUGH TEMPS WILL
START TO FALL BY MIDDAY ACROSS THE SNOW AREAS.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH 6 AM WEDNESDAY/...
TONIGHT...
EXPECT PRECIP TO TAPER OFF ACROSS THE REGION BY 01Z-02Z...THEN
VERY COLD AIR WORKS INTO THE REGION. EXPECT VERY GOOD MIXING WITH
H85 TEMPS DROPPING TO -12C TO -14C OVERNIGHT...SO EXPECT W-NW
WINDS TO PICK UP NEAR THE COAST AROUND OR AFTER MIDNIGHT. HIGHEST
GUSTS WILL BE OVER THE OUTER CAPE AND NANTUCKET.
SKIES WILL BECOME MAINLY CLEAR AS TEMPS DROP TO THE MID TEENS WELL
INLAND TO THE 20S ALONG THE IMMEDIATE COAST.
&&
.LONG TERM /WEDNESDAY THROUGH MONDAY/...
HIGHLIGHTS...
* ARCTIC AIR THU AND FRI
* POTENTIAL WINTRY PRECIPITATION SAT/SUN
WILL BE BRIEF HERE GIVEN THE EXPECTED ACTIVE WINTER WEATHER TODAY.
00Z GEFS AND ECENS ENSEMBLES ARE IN VERY GOOD AGREEMENT ON THE LARGE
SCALE FLOW ALONG WITH THE TIMING AND SMALLER SCALE DETAILS. AN
ACTIVE PATTERN CONTINUES THIS PERIOD WITH AN ARCTIC FRONTAL PASSAGE
WED NGT OR EARLY THU. BOTH ENSEMBLE DATA SETS /GEFS AND ECENS/
SUPPORT -20C AIRMASS /-2 STD FROM CLIMO/ MOVING ACROSS SOUTHERN NH
AND NORTHERN MA THU! THIS WILL LIKELY BE THE COLDEST AIRMASS OF THIS
EARLY WINTER SEASON SO FAR. THIS COLD DRY AIRMASS LINGERS INTO FRI
AS WELL. HIGHS THU AND FRI WILL ONLY REACH INTO THE 20S! NORMAL HIGH
THIS TIME OF YEAR IS IN THE U30S TO L40S.
THEN THIS WEEKEND ENSEMBLES REMAIN IN VERY GOOD AGREEMENT WITH
SOUTHERN STREAM SYSTEM EXITING THE GULF STATES AND TRACKING
NORTHEAST TO THE MID ATLC LATE SAT. COLD AIRMASS LINGERS OVER NEW
ENGLAND SAT WHICH WILL SUPPORT PTYPE ISSUES FOR THE REGION. BY 12Z
SUNDAY BOTH THE 00Z GEFS AND 12Z ECENS SUPPORT A COASTAL HUGGER WITH
LOW PRES TRACKING ALONG OR NEAR THE SOUTHERN NEW ENGLAND COAST. AT
THIS EARLY STAGE THIS SCENARIO WOULD SUGGEST A WINTRY MIX TO RAIN
FOR THE COASTAL PLAIN INCLUDING PVD/BOS CORRIDOR. HOWEVER IF THIS
STORM TRACK VERIFIES SHALLOW COLD AIR WOULD BE DIFFICULT TO SCOUR
OUT ACROSS THE INTERIOR. THUS THERE IS A RISK FOR SIGNIFICANT
ACCUMULATION OF A WINTRY MIX WELL INLAND...ESPECIALLY GIVEN THIS
SOUTHERN STREAM SYSTEM WILL HAVE PLENTY OF QPF. NEVERTHELESS THIS
POTENTIAL EVENT IS STILL 4-5 DAYS AWAY SO ITS WAY TOO EARLY TO NAIL
DOWN SPECIFICS. NONETHELESS THE POTENTIAL FOR SIGNIFICANT WINTER
STORM THIS WEEKEND EXISTS.
&&
.AVIATION /15Z TUESDAY THROUGH SATURDAY/...
FORECASTER CONFIDENCE LEVELS...
LOW...LESS THAN 30 PERCENT.
MODERATE...30 TO 60 PERCENT.
HIGH...GREATER THAN 60 PERCENT.
NEAR TERM /THROUGH TONIGHT/...
MODERATE CONFIDENCE...THOUGH LOW CONFIDENCE ON EXACT TIMING OF
LOWERING CONDITIONS.
1030 AM UPDATE...
TODAY...SNOW WILL CONTINUE TO OVERSPREAD ACROSS ALL SITES THIS
MORNING. EXPECT VSBYS AT OR BELOW 1SM AND LIFR CIGS IN POCKETS OF
SN. EXPECT LOWEST CONDITIONS NEAR AND S OF THE MASS PIKE WITH IFR-
VLIFR. ACROSS N MA/S NH...SHOULD SEE MAINLY VFR...THOUGH SOME
MVFR-IFR MAY WORK INTO NE MA /CAPE ANN AREA/ AROUND MIDDAY.
WIDESPREAD ACCUMS OF 1-3 INCHES WITH LOCALLY HIGHER AMOUNTS
ESPECIALLY ALONG THE SOUTH COAST INCLUDING THE CAPE AND ISLANDS.
SNOW MOVES EAST INTO EVENING AND TERMINALS GRADUALLY IMPROVE BACK
TO VFR.
TONIGHT...VFR FOR MOST AREAS. MVFR-IFR CIGS/VSBYS MAY LINGER OVER
CAPE COD AND THE ISLANDS THROUGH 03Z-04Z...THEN SHOULD IMPROVE.
W-NW WINDS GUSTING TO 25-30 KT ON THE OUTER CAPE AND ISLANDS.
KBOS TAF...MODERATE CONFIDENCE OVERALL...BUT LOWER CONFIDENCE ON
TIMING TODAY...THEN HIGH CONFIDENCE TONIGHT.
KBDL TAF...MODERATE CONFIDENCE OVERALL...BUT LOWER CONFIDENCE ON
TIMING TODAY...THEN HIGH CONFIDENCE TONIGHT.
OUTLOOK...WEDNESDAY THROUGH FRIDAY...MODERATE CONFIDENCE.
MAINLY VFR THRU THE PERIOD. ONLY CAVEAT WILL BE THE POSSIBILITY
OF LOCALIZED MVFR CONDITIONS IN SOME OCEAN EFFECTS -SHSN/SHRA FOR
CAPE/ISLAND TERMINALS WITH THE BEST CHANCES WED NIGHT AND THU.
STRONG NW WIND GUSTS ALSO POSSIBLE WED INTO WED NIGHT.
&&
.MARINE...
FORECASTER CONFIDENCE LEVELS...
LOW...LESS THAN 30 PERCENT.
MODERATE...30 TO 60 PERCENT.
HIGH...GREATER THAN 60 PERCENT.
NEAR TERM /THROUGH TONIGHT/...MODERATE CONFIDENCE.
TODAY...EXPECT LIGHT W-NW WINDS EARLY...WITH GUSTS INCREASING TO
AROUND 20 KT THIS AFTERNOON. SNOW WILL MOVE IN FROM W-E WITH
REDUCED VSBYS DOWN TO 1/2 MILE OR LESS. SEAS AROUND 5 FT ON THE
EASTERN OUTER WATERS EARLY EXPECTED TO SUBSIDE BY MIDDAY.
TONIGHT...SNOW WILL END EARLY THIS EVENING...BY AROUND 03Z ON THE
EASTERN OUTER WATERS. W-NW WINDS WILL INCREASE AS COLDER AIR WORKS
ACROSS THE WATERS...WITH GUSTS TO GALE FORCE FOR A TIME OVERNIGHT
ON THE OUTER WATERS. GALE WARNINGS UP THERE...WITH SMALL CRAFTS
FOR THE REMAINING WATERS. SEAS WILL ALSO BUILD...UP TO 6-8 FT ON
THE OUTER WATERS LATE.
OUTLOOK...WEDNESDAY THROUGH FRIDAY...HIGH CONFIDENCE.
A PROLONGED PERIOD OF WNW WINDS 25 KT OR HIGHER THROUGH THE PERIOD
APPEARS LIKELY. THERE IS ALSO THE LOW PROBABILITY THAT OCCASIONAL
GALE FORCE WIND GUSTS OCCUR THU BEHIND ARCTIC FRONTAL PASSAGE.
&&
.BOX WATCHES/WARNINGS/ADVISORIES...
CT...WINTER WEATHER ADVISORY UNTIL 5 PM EST THIS AFTERNOON FOR
CTZ002>004.
MA...WINTER WEATHER ADVISORY UNTIL 5 PM EST THIS AFTERNOON FOR
MAZ017>024.
NH...NONE.
RI...WINTER WEATHER ADVISORY UNTIL 5 PM EST THIS AFTERNOON FOR
RIZ001>008.
MARINE...SMALL CRAFT ADVISORY FROM 8 PM THIS EVENING TO 5 AM EST
WEDNESDAY FOR ANZ231>235-237.
SMALL CRAFT ADVISORY FROM 9 PM THIS EVENING TO 2 AM EST
WEDNESDAY FOR ANZ230-236.
GALE WARNING FROM 9 PM THIS EVENING TO 5 AM EST WEDNESDAY FOR
ANZ250-254>256.
SMALL CRAFT ADVISORY FROM 6 PM THIS EVENING TO 5 AM EST
WEDNESDAY FOR ANZ251.
&&
$$
SYNOPSIS...NOCERA/EVT
NEAR TERM...DUNTEN
SHORT TERM...EVT
LONG TERM...NOCERA
AVIATION...NOCERA/DUNTEN/EVT
MARINE...NOCERA/EVT
AREA FORECAST DISCUSSION
NWS NEW YORK NY
1019 AM EST TUE DEC 10 2013
.SYNOPSIS...
WEAK LOW PRESSURE PASSING SOUTHEAST OF LONG ISLAND THROUGH THIS
AFTERNOON. HIGH PRESSURE WILL THEN BUILD FROM THE WEST
TONIGHT...FOLLOWED BY AN APPROACHING COLD FRONT ON WEDNESDAY. THE
FRONT WILL MOVE ACROSS WEDNESDAY NIGHT...WITH HIGH PRESSURE
BUILDING IN FROM THE SOUTH AND WEST THROUGH THE END OF THE WEEK. A
COASTAL STORM WILL LIKELY IMPACT THE REGION THIS WEEKEND...WITH
HIGH PRESSURE RETURNING EARLY NEXT WEEK.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
MAIN STORY TODAY WILL BE MODERATE TO HEAVY SNOW. WINTER WEATHER
ADVISORY REMAINS IN EFFECT FOR ENTIRE FORECAST REGION. ANY DRIER
LOW LEVELS AND TEMPS A FEW DEGREES BELOW FREEZING QUICKLY WET BULB
TO NEAR FREEZING OUT EAST FOR THE TWIN FORKS OF LONG ISLAND AND
SOUTHEAST CT. TEMPS LOWER A DEGREE AND STAY FREEZING OR BELOW
THEREAFTER. THEREFORE SNOW WILL ACCUMULATE. FORCING FOR THIS IS
WELL ESTABLISHED DESPITE THE LACK OF A STRONG SURFACE LOW. DEEP
TROUGH IN THE MID LEVEL WITH POSITIVE VORTICITY ADVECTION AHEAD OF
IT REALLY WILL ENHANCE PRECIP THROUGH THE 18Z HOUR. RUC13 SHOWS
DECENT OMEGA WITHIN THE SNOW GROWTH ZONE BETWEEN -10 AND -20
DEGREES C WITH THE MORNING MODERATE TO HEAVY SNOW MOVING ACROSS.
THE FORCING AND HEAVIEST SNOW IS CONCENTRATED ALONG URBAN NE
NJ...NYC...SOUTHERN LOWER HUDSON VALLEY...SOUTHERN
CONNECTICUT...WESTERN LONG ISLAND CORRIDOR. ADDITIONAL SNOW WITH
GENERALLY LIGHT ACCUMULATIONS EXPECTED AFTER 18Z-19Z WITH
ADDITIONAL FORCING FROM POSITIVE VORTICITY ADVECTION WITH TROUGH
ALTHOUGH AMPLITUDE IS NOT AS HIGH.
OVERALL FOR STORM TOTAL...SNOW AMOUNTS OF 3 TO 5 INCHES WITH
LOCALLY HIGHER AMOUNTS POSSIBLE IN NE NJ...NYC...SOUTHERN LOWER
HUDSON VALLEY...MOST OF SOUTHERN CT...AND MOST OF LONG ISLAND.
ELSEWHERE...3 TO 4 INCHES OF SNOW. AGAIN...LOCALLY HIGHER AMOUNTS
WILL BE POSSIBLE.
ADDITIONAL SNOW WITH GENERALLY LIGHT ACCUMULATIONS EXPECTED AFTER
18Z-19Z WITH ADDITIONAL FORCING FROM POSITIVE VORTICITY ADVECTION
WITH TROUGH ALTHOUGH AMPLITUDE IS NOT AS HIGH.
CONSENSUS OF THE MODELS TAKES THE LOW TO THE SE OF THE 40N/70W
BENCHMARK BY EARLY THIS AFTERNOON. SO THIS...COUPLED WITH ONGOING
LOW LEVEL COLD AIR ADVECTION WILL YIELD A P-TYPE OF SNOW ACROSS
THE ENTIRE CWA.
TEMPERATURES ARE CRITICAL TO THIS FORECAST - EXPECT GENERALLY SLOWLY
FALLING TEMPERATURES THIS MORNING ONCE THE PRECIPITATION BEGINS...AND
THIS WILL CONTINUE INTO THIS AFTERNOON WITH THE WET-BULBING OF
TEMPERATURE - ESPECIALLY NOTING THAT LOWER DEWPOINT AIR IS BEING
ADVECTED IN THE LOWER LEVELS. THIS WILL PLACE NORTHERN ZONES IN THE
MID TO UPPER 20S AND SOUTHERN ZONES AROUND 30. THIS TEMPERATURE FALL
OFF WILL ALLOW FOR RATIOS OF AROUND 12:1 ACROSS SOUTHERN AREAS AND
15-20:1 INLAND.
RAP/NAM/GFS/SREF/ECMWF ALL SHOW AN AREA OF FAIRLY STRONG
FRONTOGENESIS FROM 700-500 HPA CROSSING THE AREA THIS MORNING TO
EARLY AFTERNOON...WITH THE CORE IF IT TRACING FROM JUST W OF NYC ON
NE INTO S CT.
GIVEN THE RATIO AND THE BANDING - APPEARS EVEN WITH QPF AROUND 1/3
OF AN INCH ACROSS SOUTHERN ZONES + AND AROUND .2" ACROSS NORTHERN
ZONES...EXPECT A 3-5" SNOWFALL ACROSS THE ENTIRE CWA WITH LOCALLY
HIGHER AMOUNTS UNDER STRONGER SNOW BANDS. THE SNOW WILL MOVE THROUGH
THE REGION FAIRLY QUICKLY...MAINLY THROUGH 21Z.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH 6 PM WEDNESDAY/...
CONDITIONS QUICKLY CLEAR OUT ACROSS MOST OF THE AREA THIS EVENING AS
THE LOW PULLS OUT WITH WEAK RIDGING BUILDING IN ALOFT THE EXCEPTION
WILL BE LAKE EFFECT CLOUDS SETTING UP ACROSS FAR NW AREAS. BLUSTERY
WINDS TONIGHT ACROSS ALL BUT WESTERN INTERIOR AREAS IN THE WAKE OF
THE STORM...WITH GUSTS OF 20-30 MPH. USED THE MINIMUM OF MAV/MET/NAM
2-METER TEMPERATURES FOR LOWS - WITH VALUES AROUND 10 DEGREES BELOW
NORMAL. DID NOT UNDERCUT GUIDANCE WITH SNOW COVER DUE TO WINDS BEING
A LIMITING FACTOR. WIND CHILLS OVERNIGHT WILL RANGE FROM 5 TO 15
DEGREES - COLDEST N OF NYC AND WARMEST OVER EASTERN LONG ISLAND.
WEAK RIDGING EXITS TO THE EAST WEDNESDAY WITH A WSW FLOW SETTING UP
ALOFT. THIS SHOULD KEEP MOST IF NOT ALL LAKE EFFECT FLURRIES/-SHSN
TO THE N OF THE AREA. MIXING WILL BE LIMITED TO AROUND 925-900 HPA
SO HIGHS WILL STRUGGLE TO REACH THE 30 DEGREE MARK IN MOST
LOCATIONS...WITH COASTAL SE CT AND THE TWIN FORKS STRUGGLING TO
REACH FREEZING. THESE HIGHS ARE CONSISTENT WITH A BLEND OF MIXING
DOWN FROM 925 HPA...EXCEPT 900 HPA WELL INLAND...WITH NAM 2-METER
TEMPERATURES AND A BLEND OF MAV/MET GUIDANCE...AND ARE AROUND 15
DEGREES BELOW NORMAL. WIND CHILLS WEDNESDAY WILL MAINLY BE IN THE
TEENS...WITH SOME AROUND 20 ACROSS COASTAL SE CT AND THE TWIN FORKS.
&&
.LONG TERM /WEDNESDAY NIGHT THROUGH MONDAY/...
THE H5 FLOW ACROSS THE EASTERN US WILL START WITH A BROAD TROUGH AND
BECOME ZONAL BY THE WEEKEND. MEANWHILE A SPLIT FLOW OUT WEST WILL
PHASE WITH TIME AS THE NORTHERN BRANCH DIGS FROM THE PAC NW TO THE
ROCKIES AND PLAINS STATES. THIS PHASING ENERGY WILL BE THE AREA TO
WATCH THROUGH THE REMAINDER OF THE WEEK AS SIGNALS FOR A COASTAL
STORM THIS WEEKEND ARE APPARENT.
AT THE SFC...A COLD FRONT WILL TRAVERSE THE AREA WED NIGHT. DEEP
LAYERED MOISTURE IS LACKING...THEREFORE EXPECT IT TO PASS DRY. A FEW
LAKE EFFECT FLURRIES MAY MAKE IT INTO FAR NW ORANGE COUNTY. COLD
WEATHER WILL CONTINUE THROUGH THE END OF THE WEEK WITH HIGHS
STRUGGLING TO REACH THE FREEZING MARK ON THU (H85 TEMPS AROUND
-15C). SIDED WITH THE COLDER GUIDANCE WITH THE SNOW PACK EXPECTED TO
REMAIN ON THE GROUND. LOWS WED NIGHT WILL GENERALLY BE IN THE LOWER
TEENS INLAND TO AROUND 20 IN METRO NY/NJ. THU NIGHT WILL BE A TAD
COLDER WITH LESS CLOUD COVER WITH TEENS AT THE COAST AND SINGLE
DIGITS INLAND. WIND CHILLS BOTH NIGHTS WILL DROP INTO THE SINGLE
DIGITS ACROSS THE AREA...AND COULD FALL BELOW ZERO THU NIGHT ACROSS
INTERIOR ZONES. CONDS WILL REMAIN DRY THROUGH FRI WITH HIGH PRES
NOSING IN FROM THE S AND W.
AS FOR THE WEEKEND SYSTEM...THE INITIAL SFC LOW ASSOCIATED WITH THE
SOUTHERN BRANCH OF THE JET STREAM IS FORECAST TO DEVELOP IN THE LEE
OF THE ROCKIES AND MOVE ACROSS THE SOUTHERN PLAINS FRI AND FRI
NIGHT. AS THE NORTHERN STREAM ENERGY PHASES WITH IT AND MOVES
TOWARDS THE MID ATLANTIC COAST...THE SYSTEM WILL STRENGTHEN AND
TRACK FROM THE MID ATLANTIC COAST JUST S AND E OF LI BEFORE LIFTING
TOWARDS NOVA SCOTIA.
THE DEVIL IS IN THE DETAILS AND THERE IS A 6-12 HOUR DIFFERENCE IN
THE TIMING BETWEEN THE OPERATIONAL EC...CMC AND GFS. THE TRACK IS
THE MOST CONSISTENT ASPECT OF THE SYSTEM AND WITH A DECENT HIGH TO
THE NE IT SHOULD BE COLD ENOUGH AT THE ONSET FOR SNOW WITH A GRADUAL
WARMING OF THE ATMOSPHERE. THE TIMING AND EXTENT OF THE CHANGEOVER
STILL NEEDS TO BE RESOLVED. THE GFS IS MUCH WARMER THAN THE EC TO
START WHICH IS A KNOWN BIAS OF THE MODEL. IT IS LIKELY ERODING THE
COLD AIR TOO QUICKLY. THIS WILL ULTIMATELY HAVE IMPACTS ON
P-TYPE...SO HAVE LOW CONFIDENCE IN THE DETAILS OF THE CURRENT
FORECAST.
HIGH PRES THEN BUILDS TOWARDS THE AREA FOR THE START OF THE NEW WORK
WEEK WITH DRY BUT COLD AND POTENTIALLY GUSTY CONDS.
&&
.AVIATION /15Z TUESDAY THROUGH SATURDAY/...
LOW PRESSURE PASSING TO THE SOUTH WILL BRING VARYING IFR/LIFR
CONDITIONS THROUGH MIDDAY...WITH IMPROVING CONDITIONS THROUGH THE
AFTERNOON INTO TONIGHT.
HEAVIEST SNOW EXPECTED INTO EARLY AFTN...TAPERING OFF FROM WEST TO
EAST DURING THE 17Z-19Z TIME PERIOD. IFR CIGS...WITH VARYING VIS
BETWEEN 1/4SM-3/4SM PSBL WITH THE SNOW.
LIGHT SNOW WITH IFR CIGS/VIS THROUGH THE AFTN...ENDING WEST TO
EAST BETWEEN 19-21Z. COULD SEE CIGS/VIS IMPROVE +1-2 HOURS SOONER
THAN IN TAF OVER ENTIRE AREA.
RUNWAY SNOWFALL TOTALS GENERALLY 3-4 INCHES.
CLEARING SKIES AND VFR CONDITIONS AFTER 21Z.
LIGHT W-NW WINDS THIS MORNING...GENERALLY 8 KTS OR LESS. WINDS
INCREASE FROM THE WNW AFTER 21Z...WITH GUSTS BETWEEN 20-25 KTS
LASTING INTO TONIGHT.
NY METRO ENHANCED AVIATION WEATHER SUPPORT...
DETAILED INFORMATION...INCLUDING HOURLY TAF WIND COMPONENT FCSTS CAN
BE FOUND AT: HTTP:/WWW.ERH.NOAA.GOV/ZNY/N90 (LOWER CASE)
KJFK FCSTER COMMENTS: BRIEF PERIODS OF VIS DOWN TO 1/4SM PSBL
THROUGH 17Z WITH +SN. WINDS MAY BE LIGHT AND VRB THRU 18Z.
KLGA FCSTER COMMENTS: BRIEF PERIODS OF VIS DOWN TO 1/4SM PSBL
THROUGH 17Z WITH +SN.
KEWR FCSTER COMMENTS: LIFR CONDITIONS MAY END +/- 1 HOUR THAN IN
TEMPO GROUP.
KTEB FCSTER COMMENTS: LIFR CONDITIONS MAY END +/- 1 HOUR THAN IN
TEMPO GROUP.
KHPN FCSTER COMMENTS: LIFR CONDITIONS MAY END +/- 1 HOUR THAN IN
TEMPO GROUP.
KISP FCSTER COMMENTS: LIFR CONDITIONS MAY END +/- 1 HOUR THAN IN
TEMPO GROUP.
.OUTLOOK FOR 15Z WED THROUGH SAT...
.WED...VFR. W WINDS G20-25KT.
.THU...VFR. W-NW G20KT.
.FRI...VFR.
.SAT...MVFR OR LOWER CONDITIONS WITH MIXED WINTRY PRECIP.
&&
.MARINE...
AFTER A LULL WITH SUB-SCA CONDITIONS...WIND GUSTS INCREASE LATE
THIS AFTERNOON TO SCA LEVELS ON THE COASTAL OCEAN WATERS LATE THIS
AFTERNOON. SINCE THIS SHOULD BE ONLY A COUPLE OF HOURS BEFORE THE
GALE WARNING STARTS...IT WILL NOT BE OF LONG ENOUGH DURATION TO
WARRANT AN SCA. GUSTS TO GALE FORCE ARE EXPECTED TONIGHT ON THE
COASTAL OCEAN WATERS...WITH GUSTS TO SCA LEVELS ELSEWHERE IN THE
WAKE OF THE DEPARTING LOW. THE SCA LEVEL GUSTS WILL LIKELY
CONTINUE ON ALL WATERS WEDNESDAY.
GALE WARNING IN EFFECT FOR THE COASTAL OCEAN WATERS FOR TONIGHT
AND A SMALL CRAFT ADVISORY FOR THE REMAINDER OF THE WATERS. WITH
CONFIDENCE NOT QUITE AT 80 PERCENT...OPTED NOT TO EXTEND THE SCA
INTO WEDNESDAY ON THE NON-OCEAN ZONES.
SCA MAY NEED TO BE CONTINUED INTO PART OF WED NIGHT WITH WINDS AND
SEAS DIMINISHING. AFTER A BRIEF LULL ON THU/THU NIGHT...CAA IS
EXPECTED TO BRING WINDS AND SEAS BACK UP WITH SCA LIKELY NEED ON AT
LEAST THE OCEAN WATERS FRI. CONDS THEN SHOULD REMAIN AT SUB-ADVY
LEVELS UNTIL THE COASTAL SYSTEM THIS WEEKEND ALTHOUGH TIMING IS
UNCERTAIN AT THIS TIME. STRONG GALES ARE POSSIBLE ON THE BACKSIDE OF
THE SYSTEM.
&&
.HYDROLOGY...
WILL RECEIVE FROM .1 TO .4 INCHES OF LIQUID EQUIVALENT
TODAY...ALMOST ALL OF IT IN THE FORM OF SNOW. NO HYDROLOGIC ISSUES
ARE EXPECTED. IT SHOULD THEN BE DRY THROUGH FRIDAY.
THERE IS THE POTENTIAL FOR SIGNIFICANT PRECIPITATION THIS WEEKEND IN
ASSOCIATION WITH A COASTAL LOW PRES SYSTEM.
&&
.EQUIPMENT...
DUE TO INTERFERENCE ISSUES WITH THE U.S. COAST GUARD
EMERGENCY BROADCAST CHANNEL...THE NEW YORK CITY NOAA ALL HAZARDS
WEATHER RADIO STATION KWO35 REMAINS OUT OF SERVICE. THE NATIONAL
WEATHER SERVICE IS WORKING WITH SEVERAL U.S. GOVERNMENT AGENCIES
TO ISOLATE AND RESOLVE THIS TECHNICAL PROBLEM.
DURING THIS TIME...THE TRANSMITTER MAY BE RETURNED TO SERVICE
INTERMITTENTLY FOR USE OF THE NOAA ALL HAZARDS WEATHER RADIO
DURING POTENTIALLY DANGEROUS WEATHER SITUATIONS...FOR ROUTINE
WEEKLY TESTS OF THE WARNING SYSTEM...AND TO DETERMINE IF THE
INTERFERENCE ISSUE HAS BEEN RESOLVED.
&&
.OKX WATCHES/WARNINGS/ADVISORIES...
CT...WINTER WEATHER ADVISORY UNTIL 5 PM EST THIS AFTERNOON FOR
CTZ005>012.
NY...WINTER WEATHER ADVISORY UNTIL 5 PM EST THIS AFTERNOON FOR
NYZ068-070>075-078>081-176>179.
WINTER WEATHER ADVISORY UNTIL 4 PM EST THIS AFTERNOON FOR
NYZ067-069.
NJ...WINTER WEATHER ADVISORY UNTIL 4 PM EST THIS AFTERNOON FOR
NJZ002-004-006-103>108.
MARINE...SMALL CRAFT ADVISORY FROM 6 PM THIS EVENING TO 6 AM EST
WEDNESDAY FOR ANZ330-335-338-340-345.
GALE WARNING FROM 6 PM THIS EVENING TO 6 AM EST WEDNESDAY FOR
ANZ350-353-355.
&&
$$
SYNOPSIS...24/MALOIT
NEAR TERM...MALOIT/JM
SHORT TERM...MALOIT
LONG TERM...24
AVIATION...SEARS
MARINE...24/MALOIT/JM
HYDROLOGY...24/MALOIT
EQUIPMENT...
AREA FORECAST DISCUSSION
NWS TAUNTON MA
707 AM EST TUE DEC 10 2013
.SYNOPSIS...
LOW PRESSURE TRACKING SOUTH OF NEW ENGLAND TODAY WILL SPREAD ACCUMULATING
SNOWS TO CONNECTICUT... RHODE ISLAND AND SOUTHEAST MASSACHUSETTS
LATER THIS MORNING AND AFTERNOON. AN ARCTIC AIRMASS OVERSPREADS
SOUTHERN NEW ENGLAND WEDNESDAY NIGHT INTO FRIDAY. A LOW PRESSURE
SYSTEM WILL LIKELY BRING A WINTRY MIX OF PRECIPITATION THIS
WEEKEND.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
7 AM UPDATE...
CLOUD TOPS COOLING ACROSS THE NORTHEAST ALONG WITH A BAROCLINIC
LEAF FORMING FROM OH-WESTERN PA INTO NY AS SHORT WAVE TROUGH RACES
NE THROUGH THE EASTERN US LONG WAVE TROUGH. SNOW NOT REACHING THE
GROUND YET ACROSS SOUTHERN NEW ENGLAND AS SURFACE OBS INDICATE
NEAREST SNOWFALL OCCURRING OVER EASTERN PA AT 7 AM. LATEST TRENDS
FROM 06Z NAM/GFS AND 03Z SREF SUGGEST A SOUTHWARD TREND IN QPF.
LATEST RUNS OF HRRR ALSO SUPPORT THIS IDEA ALONG WITH MESOSCALE
SNOW BANDS FRAGMENTED AND DISORGANIZED. NOT TOTALLY UNREALISTIC
AS WAVE REMAINS OPEN AND VERY PROGRESSIVE. THUS OUR SNOWFALL
PREDICTIONS ACROSS NORTHERN CT INTO NORTHERN RI MAY BE TOO HIGH IF
MID LEVEL FGEN AND MESOSCALE SNOW BANDS SET UP FARTHER SOUTHEAST.
WE WILL LEAVE FORECAST AS IS FOR NOW BUT ALERT ONCOMING SHIFT TO
MONITOR LATEST TRENDS. EARLIER DISCUSSION BELOW.
==================================================================
NOTING PRECIP QUICKLY BLOSSOMING ACROSS E PA/CENTRAL AND NY STATE
OVER THE LAST COUPLE OF HOURS ON NE 88D REGIONAL MOSAIC RADAR.
ALSO SEE COOLING CLOUD TOPS IN SAME GENERAL AREA ON IR SATELLITE.
HOWEVER...FEW IF ANY REPORTS FROM ASOS/S IN THOSE AREAS AT 09Z.
TEMP/DEWPT SPREADS ARE ABOUT 5-8 DEGS...STILL A BIT WIDE FOR
DEVELOPING PRECIP ALOFT.
SHORT RANGE MODELS CONTINUE TO SIGNAL VERY GOOD LOW LEVEL
MOISTURE AND LIFT WORKING UP THE COAST WELL N OF WEAK DEFORMATION
ZONE MOVING OFF THE MID ATLC COAST...ALONG WITH DIGGING H5 TROUGH
MOVING QUICKLY E OUT OF THE UPPER PLAINS. ALL ARE SHOWING QUICKLY
DEVELOPING AREA OF PRECIP...BUT STILL SOME QUESTIONS AS TO
WHERE THE CORE OF THE QPF WILL ULTIMATELY. APPEARS THAT THE GFS
AND ECMWF WERE PRETTY CLOSE...THOUGH GFS WAS A BIT FURTHER N WITH
THE HEAVIEST PRECIP ON THE 00Z RUN. THE 06Z NAM HAS SHIFTED A BIT
FURTHER S THAN ITS 00Z RUN AS WELL AS THE 06Z GFS...MORE IN LINE
WITH CURRENT THINKING. THIS...ALONG WITH THE POSITION ON THE 00Z
ECMWF...GAVE MORE CONFIDENCE TO LEAN TOWARD THE HIGHEST PRECIP
ACROSS SOUTHERN AREAS THROUGH THE DAY TODAY.
COLD AIR HAS BEEN FILTERING INTO THE REGION...AS WELL AS DIVING
PARTIAL THICKNESSES...SO NO QUESTION THAT THE BULK OF THE PRECIP
WILL BE IN THE FORM OF SNOW. ALSO NOTED VERY GOOD DENDRITIC
GROWTH REGION AROUND 15Z-20Z ACROSS THE REGION. WITH POSITIVELY
TILTED UPPER TROUGH MOVING THROUGH THE MEAN TROUGH POSITION ACROSS
THE EASTERN U.S...PRECIP WILL MOVE THROUGH RATHER QUICKLY. LOOKS
LIKE SNOW WILL BE OVER BY ABOUT THE START OF THIS EVENING/S
COMMUTE.
AGREED WITH WPC/S PLACEMENT OF THE HIGHEST QPF AND SNOWFALL ACROSS
N CT/RI AND SE MA...MAINLY ON A LINE FROM NEAR HARTFORD THROUGH
WILLIMANTIC...PROVIDENCE TO PLYMOUTH SOUTHWARD. SOME QUESTION AS
TO SNOW/WATER RATIOS ACROSS CAPE COD AND THE ISLANDS AS TEMPS
START OFF IN THE UPPER 30S...BUT SOME AREAS SHOULD SEE ADVISORY
LEVEL SNOWS. MELTED PRECIP EXPECTED ON ORDER OF 0.15 TO 0.4
INCHES AND...WITH SOME MODERATE SNOW AT TIMES WHICH WILL BRING THE
COLDER AIR DOWN...FELT THAT THERE WILL BE A GOOD AREA OF 2-4
INCHES OF SNOWFALL ACROSS SOUTHERN AREAS. BIG QUESTION AT THIS
POINT WILL BE WHETHER BANDING WILL DEVELOP CLOSE ENOUGH TO THE
COAST TO BRING HEAVIER SNOWS. AT THIS POINT...THINK THIS WILL STAY
JUST OFFSHORE...BUT SOMETHING TO BE CLOSELY MONITORED. SHOULD SEE
A PRETTY SHARP LINE OF HEAVIER SNOWFALL...BUT COULD SEE SOME LIGHT
SNOWS INTO NORTHERN MA AND POSSIBLY INTO S NH. KEPT ONLY CHANCE
POPS GOING N OF THE MASS PIKE.
WITH QUICK MOVING NATURE OF THIS SYSTEM...PRECIP WILL TAPER OFF
RATHER QUICKLY OVER N CT LATER THIS AFTERNOON...BUT MAY LINGER A
BIT ACROSS RI/SE MA INTO THE EVENING COMMUTE.
DAYTIME HIGHS WILL GENERALLY BE IN THE 30S...THOUGH TEMPS WILL
START TO FALL BY MIDDAY ACROSS THE SNOW AREAS.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH 6 AM WEDNESDAY/...
TONIGHT...
EXPECT PRECIP TO TAPER OFF ACROSS THE REGION BY 01Z-02Z...THEN
VERY COLD AIR WORKS INTO THE REGION. EXPECT VERY GOOD MIXING WITH
H85 TEMPS DROPPING TO -12C TO -14C OVERNIGHT...SO EXPECT W-NW
WINDS TO PICK UP NEAR THE COAST AROUND OR AFTER MIDNIGHT. HIGHEST
GUSTS WILL BE OVER THE OUTER CAPE AND NANTUCKET.
SKIES WILL BECOME MAINLY CLEAR AS TEMPS DROP TO THE MID TEENS WELL
INLAND TO THE 20S ALONG THE IMMEDIATE COAST.
&&
.LONG TERM /WEDNESDAY THROUGH MONDAY/...
HIGHLIGHTS...
* ARCTIC AIR THU AND FRI
* POTENTIAL WINTRY PRECIPITATION SAT/SUN
WILL BE BRIEF HERE GIVEN THE EXPECTED ACTIVE WINTER WEATHER TODAY.
00Z GEFS AND ECENS ENSEMBLES ARE IN VERY GOOD AGREEMENT ON THE LARGE
SCALE FLOW ALONG WITH THE TIMING AND SMALLER SCALE DETAILS. AN
ACTIVE PATTERN CONTINUES THIS PERIOD WITH AN ARCTIC FRONTAL PASSAGE
WED NGT OR EARLY THU. BOTH ENSEMBLE DATA SETS /GEFS AND ECENS/
SUPPORT -20C AIRMASS /-2 STD FROM CLIMO/ MOVING ACROSS SOUTHERN NH
AND NORTHERN MA THU! THIS WILL LIKELY BE THE COLDEST AIRMASS OF THIS
EARLY WINTER SEASON SO FAR. THIS COLD DRY AIRMASS LINGERS INTO FRI
AS WELL. HIGHS THU AND FRI WILL ONLY REACH INTO THE 20S! NORMAL HIGH
THIS TIME OF YEAR IS IN THE U30S TO L40S.
THEN THIS WEEKEND ENSEMBLES REMAIN IN VERY GOOD AGREEMENT WITH
SOUTHERN STREAM SYSTEM EXITING THE GULF STATES AND TRACKING
NORTHEAST TO THE MID ATLC LATE SAT. COLD AIRMASS LINGERS OVER NEW
ENGLAND SAT WHICH WILL SUPPORT PTYPE ISSUES FOR THE REGION. BY 12Z
SUNDAY BOTH THE 00Z GEFS AND 12Z ECENS SUPPORT A COASTAL HUGGER WITH
LOW PRES TRACKING ALONG OR NEAR THE SOUTHERN NEW ENGLAND COAST. AT
THIS EARLY STAGE THIS SCENARIO WOULD SUGGEST A WINTRY MIX TO RAIN
FOR THE COASTAL PLAIN INCLUDING PVD/BOS CORRIDOR. HOWEVER IF THIS
STORM TRACK VERIFIES SHALLOW COLD AIR WOULD BE DIFFICULT TO SCOUR
OUT ACROSS THE INTERIOR. THUS THERE IS A RISK FOR SIGNIFICANT
ACCUMULATION OF A WINTRY MIX WELL INLAND...ESPECIALLY GIVEN THIS
SOUTHERN STREAM SYSTEM WILL HAVE PLENTY OF QPF. NEVERTHELESS THIS
POTENTIAL EVENT IS STILL 4-5 DAYS AWAY SO ITS WAY TOO EARLY TO NAIL
DOWN SPECIFICS. NONETHELESS THE POTENTIAL FOR SIGNIFICANT WINTER
STORM THIS WEEKEND EXISTS.
&&
.AVIATION /12Z TUESDAY THROUGH SATURDAY/...
FORECASTER CONFIDENCE LEVELS...
LOW...LESS THAN 30 PERCENT.
MODERATE...30 TO 60 PERCENT.
HIGH...GREATER THAN 60 PERCENT.
NEAR TERM /THROUGH TONIGHT/...
MODERATE CONFIDENCE...THOUGH LOW CONFIDENCE ON EXACT TIMING OF
LOWERING CONDITIONS.
7 AM UPDATE...
DESPITE MANY RETURNS ON LOCAL RADAR SNOW NOT REACHING THE GROUND
AT 7 AM. SNOW AS CLOSE AS EASTERN MA. CURRENT THINKING IS FOR
HEAVIEST SNOW TO BE CONFINED TO CT/RI AND SOUTHEAST MA ESPECIALLY
THE IMMEDIATE SOUTH COAST. SNOW IS FAST MOVING WITH BACK EDGE OF
SNOW OVER CAPE COD AROUND 21Z AND BEGINNING TO MOVE OFFSHORE.
LITTLE/MINOR ACCUMULATIONS ALONG AND NORTH OF I-90 INTO BOSTON.
EARLIER DISCUSSION BELOW.
===============================================================
TODAY...EXPECT SNOW TO MOVE IN QUICKLY AFTER 12Z...WITH VSBYS
AT OR BELOW 1SM AND LIFR CIGS IN POCKETS OF SN. EXPECT LOWEST
CONDITIONS NEAR AND S OF THE MASS PIKE WITH IFR-VLIFR. ACROSS N
MA/S NH...SHOULD SEE MAINLY VFR...THOUGH SOME MVFR-IFR MAY WORK
INTO NE MA /CAPE ANN AREA/ AROUND MIDDAY.
WIDESPREAD ACCUMS OF 1-3 INCHES WITH LOCALLY HIGHER AMOUNTS
ESPECIALLY ALONG THE SOUTH COAST INCLUDING THE CAPE AND ISLANDS.
SNOW MOVES EAST INTO EVENING AND TERMINALS GRADUALLY IMPROVE BACK
TO VFR.
TONIGHT...VFR FOR MOST AREAS. MVFR-IFR CIGS/VSBYS MAY LINGER OVER
CAPE COD AND THE ISLANDS THROUGH 03Z-04Z...THEN SHOULD IMPROVE.
W-NW WINDS GUSTING TO 25-30 KT ON THE OUTER CAPE AND ISLANDS.
KBOS TAF...MODERATE CONFIDENCE OVERALL...BUT LOWER CONFIDENCE ON
TIMING TODAY...THEN HIGH CONFIDENCE TONIGHT.
KBDL TAF...MODERATE CONFIDENCE OVERALL...BUT LOWER CONFIDENCE ON
TIMING TODAY...THEN HIGH CONFIDENCE TONIGHT.
OUTLOOK...WEDNESDAY THROUGH FRIDAY...MODERATE CONFIDENCE.
MAINLY VFR THRU THE PERIOD. ONLY CAVEAT WILL BE THE POSSIBILITY
OF LOCALIZED MVFR CONDITIONS IN SOME OCEAN EFFECTS -SHSN/SHRA FOR
CAPE/ISLAND TERMINALS WITH THE BEST CHANCES WED NIGHT AND THU.
STRONG NW WIND GUSTS ALSO POSSIBLE WED INTO WED NIGHT.
&&
.MARINE...
FORECASTER CONFIDENCE LEVELS...
LOW...LESS THAN 30 PERCENT.
MODERATE...30 TO 60 PERCENT.
HIGH...GREATER THAN 60 PERCENT.
NEAR TERM /THROUGH TONIGHT/...MODERATE CONFIDENCE.
TODAY...EXPECT LIGHT W-NW WINDS EARLY...WITH GUSTS INCREASING TO
AROUND 20 KT THIS AFTERNOON. SNOW WILL MOVE IN FROM W-E WITH
REDUCED VSBYS DOWN TO 1/2 MILE OR LESS. SEAS AROUND 5 FT ON THE
EASTERN OUTER WATERS EARLY EXPECTED TO SUBSIDE BY MIDDAY.
TONIGHT...SNOW WILL END EARLY THIS EVENING...BY AROUND 03Z ON THE
EASTERN OUTER WATERS. W-NW WINDS WILL INCREASE AS COLDER AIR WORKS
ACROSS THE WATERS...WITH GUSTS TO GALE FORCE FOR A TIME OVERNIGHT
ON THE OUTER WATERS. GALE WARNINGS UP THERE...WITH SMALL CRAFTS
FOR THE REMAINING WATERS. SEAS WILL ALSO BUILD...UP TO 6-8 FT ON
THE OUTER WATERS LATE.
OUTLOOK...WEDNESDAY THROUGH FRIDAY...HIGH CONFIDENCE.
A PROLONGED PERIOD OF WNW WINDS 25 KT OR HIGHER THROUGH THE PERIOD
APPEARS LIKELY. THERE IS ALSO THE LOW PROBABILITY THAT OCCASIONAL
GALE FORCE WIND GUSTS OCCUR THU BEHIND ARCTIC FRONTAL PASSAGE.
&&
.BOX WATCHES/WARNINGS/ADVISORIES...
CT...WINTER WEATHER ADVISORY UNTIL 5 PM EST THIS AFTERNOON FOR
CTZ002>004.
MA...WINTER WEATHER ADVISORY UNTIL 5 PM EST THIS AFTERNOON FOR
MAZ017>024.
NH...NONE.
RI...WINTER WEATHER ADVISORY UNTIL 5 PM EST THIS AFTERNOON FOR
RIZ001>008.
MARINE...SMALL CRAFT ADVISORY FROM 8 PM THIS EVENING TO 5 AM EST
WEDNESDAY FOR ANZ231>235-237.
SMALL CRAFT ADVISORY FROM 9 PM THIS EVENING TO 2 AM EST
WEDNESDAY FOR ANZ230-236.
GALE WARNING FROM 9 PM THIS EVENING TO 5 AM EST WEDNESDAY FOR
ANZ250-254>256.
SMALL CRAFT ADVISORY FROM 6 PM THIS EVENING TO 5 AM EST
WEDNESDAY FOR ANZ251.
&&
$$
SYNOPSIS...NOCERA/EVT
NEAR TERM...EVT
SHORT TERM...EVT
LONG TERM...NOCERA
AVIATION...NOCERA/EVT
MARINE...NOCERA/EVT
AREA FORECAST DISCUSSION
NWS MOUNT HOLLY NJ
924 PM EST WED DEC 11 2013
.SYNOPSIS...
A REINFORCING COLD FRONT FROM THE GREAT LAKES WILL MOVE THROUGH
OVERNIGHT. HIGH PRESSURE WILL THEN BUILD ACROSS THE NORTHEAST
FRIDAY INTO SATURDAY AND MOVE NORTHEAST INTO THE CANADIAN
MARITIMES BY SUNDAY. A LOW PRESSURE SYSTEM FROM THE SOUTHWEST WILL
MOVE EAST OVER THE LOWER MISSISSIPPI VALLEY SATURDAY BEFORE
TURNING NORTHEAST WHERE IT WILL STRENGTHEN OFF THE MID ATLANTIC
COAST SUNDAY. THIS STORM WILL THEN QUICKLY MOVE INTO THE CANADIAN
MARITIMES BY MONDAY ALLOWING HIGH PRESSURE TO BUILD INTO THE AREA.
A POSSIBLE QUICK CLIPPER SYSTEM ON TUESDAY WILL BE FOLLOWED BY
HIGH PRESSURE WHICH WILL BEGIN TO PUSH IN AGAIN WEDNESDAY.
&&
.NEAR TERM /UNTIL 6 AM THURSDAY MORNING/...
ESTF UPDATE DROPPED TEMPERATURES A BIT OVER THE NEXT COUPLE OF
HOURS BASED ON CURRENT CONDITIONS. OVERNIGHT SOME CLOUDINESS ALONG
WITH AN EXPECTED INCREASE OF WINDS MAKES TEMPERATURE ADJUSTMENTS
SLIGHTLY LESS CONFIDENT. WE DID LOWER THEM A BIT TO MAKE THEM
FLOW FROM CURRENT READINGS. WE ADDED SOME FLURRIES WEST BASED ON
OBSERVATIONS IN WESTERN PA. THE LATEST HRRR AND RAP DONT SEEM TO
IMPRESSED BY IT, BUT SNOW THAT IS REACHING THE GROUND (EVEN IF ITS
NOT GOING TO BE AT .01 W/E) IS SLIGHTLY GREATER THAN THEIR
EXPECTATIONS.
A MAINLY DRY COLD FRONT AND ASSOCIATED SHORT WAVE/VORTICITY IMPULSE
ARE EXPECTED TO CROSS THE AREA OVERNIGHT TONIGHT. THIS SHOULD
BRING AN INCREASE IN CLOUD COVER TO MUCH OF THE AREA OVERNIGHT,
AND WITH A LIMITED AMOUNT OF MOISTURE, A FEW ISOLATED SNOW
SHOWERS/FLURRIES ARE POSSIBLE ACROSS OUR NORTHERN AND WESTERN
AREAS. ANY SNOW THAT DOES FALL SHOULD BE RELATIVELY LIGHT,
ALTHOUGH A COATING IS POSSIBLE, MAINLY FOR OUR HIGHEST ELEVATIONS.
IT WILL CONTINUE TO REMAIN COLD, ESPECIALLY WITH THE SNOW COVER
ACROSS THE AREA. WINDS MAY INCREASE TOWARD DAYBREAK BEHIND THE
FRONTAL BOUNDARY, WHICH COMBINED WITH THE WINDS WILL CREATE LOW
WIND CHILL TEMPERATURES. WIND CHILLS SHOULD DROP TO THE SINGLE
DIGITS TO LOW TEENS FOR MOST AREAS, WITH SOME MINUS SINGLE DIGITS
ACROSS OUR HIGHER ELEVATIONS.
&&
.SHORT TERM /6 AM THURSDAY MORNING THROUGH 6 PM THURSDAY/...
A DRY, COLD, BREEZY DAY IS EXPECTED FOR THURSDAY. THE
AFOREMENTIONED COLD FRONT WILL PUSH OFFSHORE EARLY IN THE MORNING,
WHILE HIGH PRESSURE BEGINS TO PUSH IN FROM THE WEST. THIS WILL
ALLOW WEST-NORTHWESTERLY WINDS TO INCREASE ACROSS THE AREA.
MEANWHILE, THICKNESSES WILL LOWER ACROSS THE AREA AS A TROUGH
ALOFT SWINGS ACROSS THE AREA. THIS WILL KEEP TEMPERATURES QUITE
COLD, AND WITH THE BREEZY WINDS, WIND CHILLS WILL REMAIN LOW FOR
THE DAY. WIND CHILLS WILL GENERALLY BE IN THE TEENS, WITH SOME
SINGLE DIGITS POSSIBLE, MAINLY FOR HIGHER ELEVATIONS. NO
PRECIPITATION IS EXPECTED AS DRIER AIR ALOFT MOVES ACROSS THE
AREA, ALTHOUGH AN INCREASE IN CLOUD COVER IS POSSIBLE DURING THE
DAYTIME.
&&
.LONG TERM /THURSDAY NIGHT THROUGH WEDNESDAY/...
THE LARGE-SCALE PATTERN FOR THE EXTENDED PERIOD CONTINUES TO
FEATURE A LONG-WAVE TROF OVER THE CENTRAL/EASTERN U.S. WITH SHRTWV
FEATURES MOVING THROUGH IT. TEMPERATURES WILL BE BELOW NORMAL AND
PRECIP WILL BE MOSTLY LACKING EXPCEPT FOR THE WEEKEND STORM SYSTEM
DISCUSSED BELOW. IN GENERAL THE WPC GUIDANCE WAS FOLLOW FOR
POPULATING THE LONGER-TERM GRIDS.
THE CLOSED LOW CURRENTLY OFF THE SRN CAL COAST IS FORECAST TO BE
EJECTED EWD ACROSS THE SWRN U.S. ON FRIDAY...WITH BOTH THE KICKER
AND KICK-EE CONTINUING EWD ACROSS THE CENTRAL AND ERN U.S. ON SAT
AND SUNDAY. MODELS GENERALLY INCDC THAT LOW/MID LVL WARM
ADVECTION, UPWARD VV AND NEAR-SAT RH WILL ARRIVE OVER THE FCST
AREA EARLY ON SAT MORN. MODEL QPF HANGS BACK A BIT AND MAY BE TOO
SLOW. HAVE INTRODUCED CHC POPS IN THE GRIDS PRIOR TO 12Z ON SAT.
AT THAT TIME TEMPS AT THE SFC AND ALOFT SHOULD BE COLD ENOUGH FOR
SNOW.
WARM ADVCTN WILL INCREASE DURING THE DAY SATURDAY AND THE PRECIP
SHOULD TURN OVER TO RAIN FOR AREAS MAINLY S/E OF PHL. WARM
ADVECTION ABOVE THE SFC WILL CONT SAT NIGHT BUT SUB-FREEZING AIR
AT THE SFC MAY BE HARD TO DISLODGE SAT NIGHT FOR AREAS N/W OF PHL.
THUS A MIXED BAG OF PRECIP IS LIKELY FOR THOSE AREAS. A FEW INCHES
OF SNOW/ICE ACCUMULATION IS POSSIBLE AS THE SFC LOW MOVES NEWD OFF
THE MID-ATLANTIC COAST AND DEEPENS. ALSO THERE IS THE POTENTIAL
FOR FRONTO-GEN TO PLAY HAVOC WITH SNOW AMOUNTS AS IT DID LAST SUNDAY.
MOST PRECIP IS EXPECTED TO BE OVER BY SUNDAY MORNING ALTHO THE
LASTEST ECMWF INDICATES IT MAY HOLD ON THRU PART OF THE DAY. FCST
GRIDS HAVE CHC POPS WITH RW- SOUTHEAST SW- NORHTWEST.
A FAST MOVING CLIPPER SYSTEM ACROSS THE GRTLKS ON TUES COULD BRING
A CHC OF LIGHT SNOW TO NORTHERN AREAS TUE OR TUE NIGHT. OTRW HIGH
PRES WILL PROVIDE FAIR WX WITH MODERATING TEMPS THRU THE MIDDLE OF
NEXT WEEK.
&&
.AVIATION /02Z THURSDAY THROUGH MONDAY/...
THE FOLLOWING DISCUSSION IS FOR KPHL, KPNE, KTTN, KABE, KRDG,
KILG, KMIV, KACY AND SURROUNDING AREAS.
VFR CONDITIONS EXPECTED THROUGH THE PERIOD. HIGH LEVEL CLOUDS EARLY
TONIGHT, BEFORE LOWER CLOUDS MOVE IN OVERNIGHT WITH A DRY FRONTAL
PASSAGE, BUT STILL VFR. ADDITIONAL CLOUD COVER IS POSSIBLE THURSDAY,
BUT SHOULD REMAIN VFR.
GUSTY WINDS THIS AFTERNOON WILL DROP OFF OVERNIGHT, BEFORE BECOMING
GUSTY AGAIN ON THURSDAY BEHIND THE FRONTAL PASSAGE.
OUTLOOK...
FRIDAY...VFR CONDS WITH WEST WIND AROUND 10 MPH.
SATURDAY AND SUNDAY...CONDS DETERIORATING TO IFR ON SATURDAY WITH
MIXED PRECIP TYPES AND FOG. EAST WINDS AROUND 10 MPH ON SAT WILL
SHIFT TO NW 15 TO 20 MPH ON SUNDAY AS THE STORM MOVES OFFSHORE.
CONDS SHOULD IMPROVE TO VFR AGAIN BY SUNDAY AFTN.
MONDAY...VFR CONDS WITH LIGHT WINDS.
&&
.MARINE...
THE SMALL CRAFT ADVISORY FOR THE NORTHERN WATERS
REMAINS IN EFFECT ALTHOUGH WINDS HAVE DROPPED OFF BELOW ADVISORY
LEVELS FOR NOW. THE WINDS WILL INCREASE LATER THIS EVENING INTO
THE OVERNIGHT HOURS AND CONTINUE INTO THURSDAY. A SMALL CRAFT
ADVISORY HAS BEEN ISSUED OR THE REMAINDER OF THE WATERS, INCLUDING
THE DELAWARE BAY. WINDS ARE EXPECTED TO INCREASE OVERNIGHT BEHIND
THE FRONTAL BOUNDARY, AND CONTINUE INTO THURSDAY.
OUTLOOK...
FRIDAY...SMALL CRAFT ADVISORY CONDITIONS MAY CONTINUE THROUGH
EARLY MORNING BUT WINDS AND SEAS SHOULD SUBSIDE BELOW SCA BY
AFTERNOON.
SATURDAY AND SUNDAY...A STORM IS FORECAST TO DEVELOP OFF OF OUR
COAST LATE SATURDAY INTO SUNDAY THEN MOVE TOWARD THE CANADIAN
MARITIMES. AT LEAST A SMALL CRAFT ADVISORY WILL LIKELY BE NEEDED
IN NW WINDS BEHIND THE STORM FROM SUNDAY EVENING INTO MONDAY.
MONDAY...WINDS AND SEAS SHOULD SUBSIDE AS HIGH PRESSURE MOVES OVER
THE AREA.
&&
.PHI WATCHES/WARNINGS/ADVISORIES...
PA...NONE.
NJ...NONE.
DE...NONE.
MD...NONE.
MARINE...SMALL CRAFT ADVISORY UNTIL 7 AM EST FRIDAY FOR ANZ452>455.
SMALL CRAFT ADVISORY UNTIL 7 AM EST FRIDAY FOR ANZ450-451.
SMALL CRAFT ADVISORY FROM 5 AM TO 6 PM EST THURSDAY FOR ANZ430-
431.
&&
$$
SYNOPSIS...AMC/GORSE/99
NEAR TERM...GIGI/ROBERTSON
SHORT TERM...ROBERTSON
LONG TERM...AMC
AVIATION...AMC/ROBERTSON
MARINE...AMC/ROBERTSON
AREA FORECAST DISCUSSION
NWS MIAMI FL
1231 AM EST TUE DEC 10 2013
.AVIATION...
VFR CONDITIONS WILL BE PREVALENT INTO WEDNESDAY. A FEW MAINLY
AFTERNOON AND OVERNIGHT SHOWERS ARE POSSIBLE...BUT PROBS ARE LOW
AND VCSH LEFT OUT OF 6Z TAFS. WINDS WILL BE LIGHT AND SE
TONIGHT...INCREASING TO 10 KTS TUESDAY. GULF BREEZE SHOULD
TRANSITION WINDS TUESDAY AFTERNOON AT NAPLES TO WSW.
&&
.PREV DISCUSSION... /ISSUED 817 PM EST MON DEC 9 2013/
UPDATE...
HIGH PRESSURE WILL REMAIN OVER THE WESTERN ATLANTIC WATERS
EXTENDING BACK WEST INTO SOUTH FLORIDA...AS A COLD FRONT SLOWLY
DRIFTS SOUTH THROUGH NORTH FLORIDA. THIS WILL KEEP THE WEATHER DRY
OVER SOUTH FLORIDA TONIGHT ALONG WITH LIGHT WINDS AND MOSTLY CLEAR
SKIES OVER THE MAINLAND AREAS. SO FOG FORMATION IS EXPECTED
OVERNIGHT TONIGHT OVER THE INTERIOR AND WEST COAST METRO
AREAS...WITH EVEN AREAS OF FOG OVER THE INTERIOR SECTION TOWARDS
SUNRISE.
FOR THE MARINE SECTION OF SOUTH FLORIDA...THE WINDS WILL REMAIN
FROM THE EASTERLY DIRECTION AT 10 TO 15 KNOTS TONIGHT. THIS WILL
KEEP THE SEAS IN THE ATLANTIC WATERS AT 2 TO 4 FEET AND IN THE
GULF WATERS AT 1 TO 3 FEET. SO ON CHANGES ARE EXPECTED IN THE
MARINE PACKAGE FOR TONIGHT.
REST OF THE FORECAST LOOKS GOOD AT THIS TIME AND NO OTHER CHANGES
ARE PLANNED.
UPDATE...54/BNB
PREV DISCUSSION... /ISSUED 152 PM EST MON DEC 9 2013/
DISCUSSION...
QUIET WEATHER WILL CONTINUE THROUGH TONIGHT, WITH WINDS BECOMING
LIGHT AND VARIABLE TO CALM OVER THE INTERIOR AREAS. THERE COULD BE A
ROUND OF FOG DEVELOPMENT. THE HRRR DOES KEEP IT OUT OF ITS
FORECAST THROUGH 04Z, WHICH IS THE EXTENT OF THE RUN AT THIS TIME.
HOWEVER, BUFKIT IS SHOWING THAT IT DOES FAVOR FOG. SO, HAVE KEPT
PATCHY FOG IN THE FORECAST FROM 06Z THROUGH 12Z.
PATTERN WISE, HIGH PRESSURE WILL WEAKEN THROUGH THE NIGHT. THIS IS
AHEAD OF A COLD FRONT THAT IS CURRENTLY WELL TO THE WEST, OVER NEW
ORLEANS. THIS FRONT WILL APPROACH THE FLORIDA PENINSULA AND WILL
BE ENHANCED BY A 500 MB SHORT WAVE. HOWEVER, AS IT APPROACHES
FLORIDA, THE ASSOCIATED LOW WILL BE QUICKLY MOVING OFF TO THE
NORTHEAST, TAKING MOST OF THE ENERGY AND MOISTURE WITH IT. THIS
WILL CAUSE THE FRONT TO STALL SOMEWHERE OVER NORTH CENTRAL
FLORIDA WEDNESDAY NIGHT.
AHEAD OF THIS FRONT, THERE WILL BE AN AREA OF CLOUDS AND SHOWERS
THAT WILL BEGIN TO AFFECT THE SOUTHERN TIP OF FLORIDA TOMORROW
MORNING. MODELS ARE IN DISAGREEMENT WITH THE EXTENT OF THE
COVERAGE OF THE SHOWERS. THE GFS KEEPS MOST OF THE ACTIVITY TO THE
SOUTH OF I75, BUT IT DOES HAVE SHOWERS OVER THE PENINSULA. THE
ECMWF KEEPS ALL ACTIVITY OFFSHORE, EXCEPT PERHAPS A LIGHT COASTAL
SHOWER. HAVE KEPT A CHANCE OF SHOWERS FOR MOST AREAS SOUTH OF I75
AND A SLIGHT CHANCE NORTH OF THAT FOR THE AFTERNOON HOURS. AFTER
THAT, MOST OF THE ACTIVITY IS EITHER OVER THE COASTAL WATERS, OR
JUST ALONG THE COAST, WITH INLAND AREAS FAIRLY DRY.
BY WEDNESDAY AFTERNOON, THE FRONT LOOKS TO DRIFT FAR ENOUGH SOUTH
TO BRING A CHANCE OF SHOWERS TO AREAS NORTH OF I75. AFTER THAT, A
SECONDARY HIGH BUILDS OVER THE MISSISSIPPI VALLEY, WHICH WILL PUSH
THE FRONT FURTHER SOUTH AND OVER THE FLORIDA STRAIGHTS. AS IT
DOES, IT MAY ENHANCE SHOWER ACTIVITY THURSDAY AFTERNOON AND
EVENING. THEN, EASTERLY FLOW RETURNS AS THE SURFACE HIGH SLIDES
EASTWARD. ALSO, AN UPPER LEVEL RIDGE WILL BE BUILDING OVER THE
AREA FOR THE WEEKEND. THIS WILL PROBABLY BRING MOSTLY DRY
CONDITIONS FOR THE WEEKEND, WITH THE EXCEPTION OF A SLIGHT CHANCE
OF SHOWERS BY SUNDAY.
MARINE...
HIGH PRESSURE WILL BEGIN TO WEAKEN TONIGHT. THIS WILL BRING WINDS
AROUND TO THE SOUTH TOMORROW AS WELL AS SOME SHOWERS TO THE SOUTH
FLORIDA COASTAL WATERS. A COLD FRONT WILL APPROACH THE AREA
WEDNESDAY NIGHT AND STALL OVER CENTRAL FLORIDA AND ALL BUT
DISSIPATE. HIGH PRESSURE WILL QUICKLY TO THE NORTH, BEHIND THE
FRONT. THIS WILL BRING AN EASTERLY FLOW BACK TO THE SOUTH FLORIDA
WATERS WEDNESDAY. WITH THE WEAK FRONTAL BOUNDARY IN THE AREA, IT
WILL BRING A CHANCE OF SHOWERS FOR THE COASTAL WATERS THROUGH THE
END OF THE WEEK.
&&
.PRELIMINARY POINT TEMPS/POPS...
WEST PALM BEACH 70 82 68 80 / 20 30 20 30
FORT LAUDERDALE 71 82 70 82 / 30 30 20 30
MIAMI 72 83 70 83 / 30 30 20 30
NAPLES 67 82 66 83 / 20 30 20 20
&&
.MFL WATCHES/WARNINGS/ADVISORIES...
FL...NONE.
AM...NONE.
GM...NONE.
&&
$$
DISCUSSION/MARINE/FIRE...84/AK
AVIATION/RADAR...23/SK
AREA FORECAST DISCUSSION...UPDATED
NWS PEACHTREE CITY GA
100 PM EST TUE DEC 10 2013
.PREV DISCUSSION... /ISSUED 358 AM EST TUE DEC 10 2013/
SHORT TERM /TODAY THROUGH WEDNESDAY/...
SHORT TERM MODELS ARE IN GOOD AGREEMENT FOR THE MOST PART ALTHOUGH
SOME DISCREPANCIES NOTED...NAM/SREF FASTER AND GFS/ECMWF SLOWER TO
PUSH FRONT THROUGH FORECAST AREA TODAY. RAP HAS INITIALIZED WELL
AND IS HANDLING THE RAIN BAND OVER NORTHWEST GEORGIA FAIRLY WELL AND
IS IN LINE WITH FASTER SOLUTIONS. TEMPERATURES REMAIN IN THE LOWER
40S ACROSS NORTHWEST GEORGIA AND WITH SLOW PROGRESS OF COLDER AIR TO
THE NORTH DO NOT EXPECT WINTRY PRECIP IN THE FORECAST AREA. COLDER
AIR WILL FILTER INTO PORTIONS OF NORTH GEORGIA BY MID-LATE
MORNING...AND MODELS ARE TRYING TO SCATTER/CLEAR SKIES RAPIDLY
BEHIND THE FRONT. THIS WILL RESULT IN MAXIMUM TEMPERATURES ACROSS
NORTH GEORGIA...INCLUDING THE ATLANTA METRO AREA...THIS MORNING.
COLD AIR ADVECTION BEHIND THE FRONT IS NOT IMPRESSIVE...BUT SHOULD
BE ENOUGH TO OFFSET ANY HEATING BY THE SCATTERING CLOUDS WHICH
WILL RESULT IN SEVERAL HOURS OF NEAR STEADY TEMPERATURES ACROSS
NORTH GEORGIA. 1000-850 WINDS WILL INCREASE BEHIND THE FRONT WITH
GUSTS OF 25-30MPH EXPECTED BY LATE MORNING IN NORTH
GEORGIA...SPREADING SOUTHWARD INTO CENTRAL GEORGIA BY EARLY
AFTERNOON AND CONTINUING THROUGH EARLY THIS EVENING. DRIER AIR
FILTERING INTO THE FORECAST AREA BY TONIGHT...BUT WIND SPEEDS WILL
REMAIN IN THE 5-10MPH RANGE OVERNIGHT WHICH WILL KEEP TEMPERATURES
FROM RADIATING OUT AS MUCH AS THEY COULD...HOWEVER TEMPERATURES WILL
DROP TO LOWER TO MID 20S NORTH GEORGIA AND IN THE MID 30S OVER
CENTRAL GEORGIA BY MORNING. TEMPERATURES WILL MODERATE ON WEDNESDAY
TO NEAR NORMAL AS DRY WEATHER AND MOSTLY CLEAR SKIES SET UP ACROSS
THE AREA.
ATWELL
LONG TERM /WEDNESDAY NIGHT THROUGH MONDAY/...
EXTENDED BEGINS WITH LONGWAVE TROUGH DOMINATING THE EASTERN HALF
OF THE COUNTRY...WITH ANOTHER SHORTWAVE DIVING THROUGH THE CENTRAL
PLAINS. THIS DRY WAVE WILL PUSH INTO THE SOUTHEAST THURSDAY
MORNING BUT WILL BRING A REINFORCING SHOT OF COOL AIR TO THE
REGION. WEAK RIDGING BUILDS IN ALOFT FRIDAY AHEAD OF A STRONG
SYSTEM OVER THE DESERT SOUTHWEST. SURFACE LOW WILL PUSH INTO THE
SOUTHERN PLAINS FRIDAY NIGHT...WITH STRONG SOUTHERLIES PUMPING
GULF MOISTURE BACK INTO THE SOUTHEAST. PRECIP OVERSPREADS THE AREA
FRIDAY NIGHT AND ESPECIALLY SATURDAY...AND GIVEN AGREEMENT BETWEEN
GFS AND ECMWF AS WELL AS RUN-TO-RUN CONSISTENCY...HAVE INCREASED
POPS TO CATEGORICAL ON SATURDAY. LOOKS LIKE EASILY ANOTHER INCH OF
RAIN ACROSS THE AREA. THERE MAY BE ENOUGH INSTABILITY CREEPING
INTO SOUTHERN ZONES SATURDAY AFTERNOON TO WARRANT ADDING THUNDER
TO THE FORECAST...BUT HAVE LEFT IT OUT FOR NOW.
COMPLICATING FACTOR IS DIABATICALLY ENHANCED CLASSICAL CAD
DEVELOPING FRIDAY NIGHT AND EARLY SATURDAY...THOUGH RIGHT NOW
THICKNESSES ACROSS GEORGIA FOR THE MOST PART LOOK TOO WARM FOR ANY
WINTRY PRECIP...BUT LATER FORECASTS WILL HAVE TO BE REEVALUATED.
DID ADD A BRIEF RAIN/SNOW MIX EXTREME NORTH SUNDAY MORNING AS THE
COLD FRONT PUSHES THROUGH. GFS IS JUST A TAD FASTER THAN THE ECMWF
BY THIS POINT SO UNCERTAINTY IS INCREASING. COOL AND WINDY BEHIND
THE FRONT BUT CLEARING INTO EARLY NEXT WEEK.
TDP
&&
AVIATION...
18Z UPDATE...
MVFR TO VFR CONDITIONS CURRENTLY WITH VFR CONDITIONS AREAWIDE BY
19-21Z...CONTINUING THROUGH THE REMAINDER OF THE FORECAST PERIOD.
WINDS WILL REMAIN NWLY 10-16KT W/ G18-28KT THROUGH 22-24Z...BECOMING
NW-N 3-6KT BY 04Z AND EVENTUALLY NE 3-5KT BY 12-14Z.
//ATL CONFIDENCE...18Z UPDATE...
HIGH.
20
&&
.PRELIMINARY POINT TEMPS/POPS...
ATHENS 53 28 55 29 / 80 0 5 5
ATLANTA 50 30 55 31 / 80 0 5 5
BLAIRSVILLE 47 22 52 23 / 60 0 5 5
CARTERSVILLE 48 24 53 26 / 70 0 5 5
COLUMBUS 59 32 59 36 / 50 0 5 5
GAINESVILLE 50 29 53 31 / 80 0 5 5
MACON 61 28 58 30 / 60 0 5 5
ROME 47 22 52 25 / 50 0 5 5
PEACHTREE CITY 49 25 55 28 / 80 0 5 5
VIDALIA 69 39 59 40 / 50 5 5 5
&&
.FFC WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...ATWELL
LONG TERM....TDP
AVIATION...ATWELL
AREA FORECAST DISCUSSION
NWS PEACHTREE CITY GA
632 AM EST TUE DEC 10 2013
.PREV DISCUSSION... /ISSUED 358 AM EST TUE DEC 10 2013/
SHORT TERM /TODAY THROUGH WEDNESDAY/...
SHORT TERM MODELS ARE IN GOOD AGREEMENT FOR THE MOST PART ALTHOUGH
SOME DISCREPANCIES NOTED...NAM/SREF FASTER AND GFS/ECMWF SLOWER TO
PUSH FRONT THROUGH FORECAST AREA TODAY. RAP HAS INITIALIZED WELL
AND IS HANDLING THE RAIN BAND OVER NORTHWEST GEORGIA FAIRLY WELL AND
IS IN LINE WITH FASTER SOLUTIONS. TEMPERATURES REMAIN IN THE LOWER
40S ACROSS NORTHWEST GEORGIA AND WITH SLOW PROGRESS OF COLDER AIR TO
THE NORTH DO NOT EXPECT WINTRY PRECIP IN THE FORECAST AREA. COLDER
AIR WILL FILTER INTO PORTIONS OF NORTH GEORGIA BY MID-LATE
MORNING...AND MODELS ARE TRYING TO SCATTER/CLEAR SKIES RAPIDLY
BEHIND THE FRONT. THIS WILL RESULT IN MAXIMUM TEMPERATURES ACROSS
NORTH GEORGIA...INCLUDING THE ATLANTA METRO AREA...THIS MORNING.
COLD AIR ADVECTION BEHIND THE FRONT IS NOT IMPRESSIVE...BUT SHOULD
BE ENOUGH TO OFFSET ANY HEATING BY THE SCATTERING CLOUDS WHICH
WILL RESULT IN SEVERAL HOURS OF NEAR STEADY TEMPERATURES ACROSS
NORTH GEORGIA. 1000-850 WINDS WILL INCREASE BEHIND THE FRONT WITH
GUSTS OF 25-30MPH EXPECTED BY LATE MORNING IN NORTH
GEORGIA...SPREADING SOUTHWARD INTO CENTRAL GEORGIA BY EARLY
AFTERNOON AND CONTINUING THROUGH EARLY THIS EVENING. DRIER AIR
FILTERING INTO THE FORECAST AREA BY TONIGHT...BUT WIND SPEEDS WILL
REMAIN IN THE 5-10MPH RANGE OVERNIGHT WHICH WILL KEEP TEMPERATURES
FROM RADIATING OUT AS MUCH AS THEY COULD...HOWEVER TEMPERATURES WILL
DROP TO LOWER TO MID 20S NORTH GEORGIA AND IN THE MID 30S OVER
CENTRAL GEORGIA BY MORNING. TEMPERATURES WILL MODERATE ON WEDNESDAY
TO NEAR NORMAL AS DRY WEATHER AND MOSTLY CLEAR SKIES SET UP ACROSS
THE AREA.
ATWELL
LONG TERM /WEDNESDAY NIGHT THROUGH MONDAY/...
EXTENDED BEGINS WITH LONGWAVE TROUGH DOMINATING THE EASTERN HALF
OF THE COUNTRY...WITH ANOTHER SHORTWAVE DIVING THROUGH THE CENTRAL
PLAINS. THIS DRY WAVE WILL PUSH INTO THE SOUTHEAST THURSDAY
MORNING BUT WILL BRING A REINFORCING SHOT OF COOL AIR TO THE
REGION. WEAK RIDGING BUILDS IN ALOFT FRIDAY AHEAD OF A STRONG
SYSTEM OVER THE DESERT SOUTHWEST. SURFACE LOW WILL PUSH INTO THE
SOUTHERN PLAINS FRIDAY NIGHT...WITH STRONG SOUTHERLIES PUMPING
GULF MOISTURE BACK INTO THE SOUTHEAST. PRECIP OVERSPREADS THE AREA
FRIDAY NIGHT AND ESPECIALLY SATURDAY...AND GIVEN AGREEMENT BETWEEN
GFS AND ECMWF AS WELL AS RUN-TO-RUN CONSISTENCY...HAVE INCREASED
POPS TO CATEGORICAL ON SATURDAY. LOOKS LIKE EASILY ANOTHER INCH OF
RAIN ACROSS THE AREA. THERE MAY BE ENOUGH INSTABILITY CREEPING
INTO SOUTHERN ZONES SATURDAY AFTERNOON TO WARRANT ADDING THUNDER
TO THE FORECAST...BUT HAVE LEFT IT OUT FOR NOW.
COMPLICATING FACTOR IS DIABATICALLY ENHANCED CLASSICAL CAD
DEVELOPING FRIDAY NIGHT AND EARLY SATURDAY...THOUGH RIGHT NOW
THICKNESSES ACROSS GEORGIA FOR THE MOST PART LOOK TOO WARM FOR ANY
WINTRY PRECIP...BUT LATER FORECASTS WILL HAVE TO BE REEVALUATED.
DID ADD A BRIEF RAIN/SNOW MIX EXTREME NORTH SUNDAY MORNING AS THE
COLD FRONT PUSHES THROUGH. GFS IS JUST A TAD FASTER THAN THE ECMWF
BY THIS POINT SO UNCERTAINTY IS INCREASING. COOL AND WINDY BEHIND
THE FRONT BUT CLEARING INTO EARLY NEXT WEEK.
TDP
AVIATION...
06Z UPDATE...
IFR TO MVFR CONDITIONS WILL DETERIORATE TO IFR...SOME LIFR AT TAF
SITES. LIGHT RAIN MOVING ACROSS TAF SITES MAINLY THIS MORNING WILL
AID IN IMPROVING CIGS TO MVFR. COLDER AIR FILTERING IN MAY STALL
CLEARING SKIES BUT WILL GO VFR AFTER 18-20Z. WINDS WILL INCREASE
OUT OF NW 10-15KTS WITH GUSTS TO 27KTS EXPECTED.
//ATL CONFIDENCE...06Z UPDATE...
MEDIUM CONFIDENCE ALL ELEMENTS.
ATWELL
&&
.AVIATION...
12Z UPDATE...
IMPROVING TRENDS EXPECTED TODAY. LIGHT RAIN ASSOCIATED WITH THE
COLDFRONT WILL WORK ITS WAY ACROSS THE TAF SITES 15-17Z. CIGS WILL
IMPROVE TO MVFR/VFR AFTER 17Z. NORTHWEST WINDS WILL INCREASE TO
15-20KTS WITH GUSTS TO 27 THROUGH THIS AFTERNOON. WINDS WILL SHIFT
OUT OF THE NORTHEAST AND BECOME LIGHT DURING THE OVERNIGHT HOURS.
//ATL CONFIDENCE...12Z UPDATE...
MEDIUM CONFIDENCE IN CIGS.
MEDIUM TO HIGH CONFIDENCE IN ALL OTHER ELEMENTS.
ATWELL
&&
.PRELIMINARY POINT TEMPS/POPS...
ATHENS 53 28 55 29 / 80 0 5 5
ATLANTA 50 30 55 31 / 80 0 5 5
BLAIRSVILLE 47 22 52 23 / 60 0 5 5
CARTERSVILLE 48 24 53 26 / 70 0 5 5
COLUMBUS 59 32 59 36 / 50 0 5 5
GAINESVILLE 50 29 53 31 / 80 0 5 5
MACON 61 28 58 30 / 60 0 5 5
ROME 47 22 52 25 / 50 0 5 5
PEACHTREE CITY 49 25 55 28 / 80 0 5 5
VIDALIA 69 39 59 40 / 50 5 5 5
&&
.FFC WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...ATWELL
LONG TERM....TDP
AVIATION...ATWELL
AREA FORECAST DISCUSSION
NWS PEACHTREE CITY GA
358 AM EST TUE DEC 10 2013
.SHORT TERM /TODAY THROUGH WEDNESDAY/...
SHORT TERM MODELS ARE IN GOOD AGREEMENT FOR THE MOST PART ALTHOUGH
SOME DISCREPANCIES NOTED...NAM/SREF FASTER AND GFS/ECMWF SLOWER TO
PUSH FRONT THROUGH FORECAST AREA TODAY. RAP HAS INITIALIZED WELL
AND IS HANDLING THE RAIN BAND OVER NORTHWEST GEORGIA FAIRLY WELL AND
IS IN LINE WITH FASTER SOLUTIONS. TEMPERATURES REMAIN IN THE LOWER
40S ACROSS NORTHWEST GEORGIA AND WITH SLOW PROGRESS OF COLDER AIR TO
THE NORTH DO NOT EXPECT WINTRY PRECIP IN THE FORECAST AREA. COLDER
AIR WILL FILTER INTO PORTIONS OF NORTH GEORGIA BY MID-LATE
MORNING...AND MODELS ARE TRYING TO SCATTER/CLEAR SKIES RAPIDLY
BEHIND THE FRONT. THIS WILL RESULT IN MAXIMUM TEMPERATURES ACROSS
NORTH GEORGIA...INCLUDING THE ATLANTA METRO AREA...THIS MORNING.
COLD AIR ADVECTION BEHIND THE FRONT IS NOT IMPRESSIVE...BUT SHOULD
BE ENOUGH TO OFFSET ANY HEATING BY THE SCATTERING CLOUDS WHICH
WILL RESULT IN SEVERAL HOURS OF NEAR STEADY TEMPERATURES ACROSS
NORTH GEORGIA. 1000-850 WINDS WILL INCREASE BEHIND THE FRONT WITH
GUSTS OF 25-30MPH EXPECTED BY LATE MORNING IN NORTH
GEORGIA...SPREADING SOUTHWARD INTO CENTRAL GEORGIA BY EARLY
AFTERNOON AND CONTINUING THROUGH EARLY THIS EVENING. DRIER AIR
FILTERING INTO THE FORECAST AREA BY TONIGHT...BUT WIND SPEEDS WILL
REMAIN IN THE 5-10MPH RANGE OVERNIGHT WHICH WILL KEEP TEMPERATURES
FROM RADIATING OUT AS MUCH AS THEY COULD...HOWEVER TEMPERATURES WILL
DROP TO LOWER TO MID 20S NORTH GEORGIA AND IN THE MID 30S OVER
CENTRAL GEORGIA BY MORNING. TEMPERATURES WILL MODERATE ON WEDNESDAY
TO NEAR NORMAL AS DRY WEATHER AND MOSTLY CLEAR SKIES SET UP ACROSS
THE AREA.
ATWELL
.LONG TERM /WEDNESDAY NIGHT THROUGH MONDAY/...
EXTENDED BEGINS WITH LONGWAVE TROUGH DOMINATING THE EASTERN HALF
OF THE COUNTRY...WITH ANOTHER SHORTWAVE DIVING THROUGH THE CENTRAL
PLAINS. THIS DRY WAVE WILL PUSH INTO THE SOUTHEAST THURSDAY
MORNING BUT WILL BRING A REINFORCING SHOT OF COOL AIR TO THE
REGION. WEAK RIDGING BUILDS IN ALOFT FRIDAY AHEAD OF A STRONG
SYSTEM OVER THE DESERT SOUTHWEST. SURFACE LOW WILL PUSH INTO THE
SOUTHERN PLAINS FRIDAY NIGHT...WITH STRONG SOUTHERLIES PUMPING
GULF MOISTURE BACK INTO THE SOUTHEAST. PRECIP OVERSPREADS THE AREA
FRIDAY NIGHT AND ESPECIALLY SATURDAY...AND GIVEN AGREEMENT BETWEEN
GFS AND ECMWF AS WELL AS RUN-TO-RUN CONSISTENCY...HAVE INCREASED
POPS TO CATEGORICAL ON SATURDAY. LOOKS LIKE EASILY ANOTHER INCH OF
RAIN ACROSS THE AREA. THERE MAY BE ENOUGH INSTABILITY CREEPING
INTO SOUTHERN ZONES SATURDAY AFTERNOON TO WARRANT ADDING THUNDER
TO THE FORECAST...BUT HAVE LEFT IT OUT FOR NOW.
COMPLICATING FACTOR IS DIABATICALLY ENHANCED CLASSICAL CAD
DEVELOPING FRIDAY NIGHT AND EARLY SATURDAY...THOUGH RIGHT NOW
THICKNESSES ACROSS GEORGIA FOR THE MOST PART LOOK TOO WARM FOR ANY
WINTRY PRECIP...BUT LATER FORECASTS WILL HAVE TO BE REEVALUATED.
DID ADD A BRIEF RAIN/SNOW MIX EXTREME NORTH SUNDAY MORNING AS THE
COLD FRONT PUSHES THROUGH. GFS IS JUST A TAD FASTER THAN THE ECMWF
BY THIS POINT SO UNCERTAINTY IS INCREASING. COOL AND WINDY BEHIND
THE FRONT BUT CLEARING INTO EARLY NEXT WEEK.
TDP
&&
.AVIATION...
06Z UPDATE...
IFR TO MVFR CONDITIONS WILL DETERIORATE TO IFR...SOME LIFR AT TAF
SITES. LIGHT RAIN MOVING ACROSS TAF SITES MAINLY THIS MORNING WILL
AID IN IMPROVING CIGS TO MVFR. COLDER AIR FILTERING IN MAY STALL
CLEARING SKIES BUT WILL GO VFR AFTER 18-20Z. WINDS WILL INCREASE
OUT OF NW 10-15KTS WITH GUSTS TO 27KTS EXPECTED.
//ATL CONFIDENCE...06Z UPDATE...
MEDIUM CONFIDENCE ALL ELEMENTS.
ATWELL
&&
.PRELIMINARY POINT TEMPS/POPS...
ATHENS 53 28 55 29 / 80 0 5 5
ATLANTA 50 30 55 31 / 80 0 5 5
BLAIRSVILLE 47 22 52 23 / 60 0 5 5
CARTERSVILLE 48 24 53 26 / 70 0 5 5
COLUMBUS 59 32 59 36 / 50 0 5 5
GAINESVILLE 50 29 53 31 / 80 0 5 5
MACON 61 28 58 30 / 80 0 5 5
ROME 47 22 52 25 / 50 0 5 5
PEACHTREE CITY 49 25 55 28 / 80 0 5 5
VIDALIA 69 39 59 40 / 70 5 5 5
&&
.FFC WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...ATWELL
LONG TERM....TDP
AVIATION...ATWELL
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
146 PM CST TUE DEC 10 2013
.DISCUSSION...
947 AM CST
FOR MORNING UPDATE...
ONLY MINOR EDITS TO MORNING GRIDS/FORECASTS BASED ON CURRENT
OBSERVATIONAL DATA. HAVE ENDED SNOW SHOWERS AND REPLACED WITH
SCATTERED FLURRIES ACROSS NORTH CENTRAL IL THROUGH LATE MORNING AND
LOWERED HIGH TEMPS A COUPLE OF DEGREES ESPECIALLY SOUTH.
MORNING GOES VAPOR IMAGERY AND RAP INITIALIZATION OF UPPER AIR DATA
DEPICTS MID-LEVEL SHORT WAVE TROUGH MOVING ACROSS THE FORECAST AREA
AT MID-MORNING. AREA OF LIGHT SNOW/SNOW SHOWERS ASSOCIATED WITH THIS
DISTURBANCE WAS MOVING EAST ACROSS THE CWA...MAINLY THE IMMEDIATE
CHICAGO AREA AND ADJACENT NORTHWEST INDIANA/SOUTHERN LAKE MICHIGAN.
A FEW FLURRIES LINGERING BACK ACROSS PARTS OF NORTH CENTRAL IL...
WITH SKIES OTHERWISE BECOMING PARTLY CLOUDY/MOSTLY SUNNY FROM THE
WEST AS THE MID LEVEL WAVE CONTINUES TO TRACK OFF TO THE EAST
THROUGH MID-DAY. AT THE SURFACE...WEAK SURFACE LOW OVER WI PROGGED
TO CONSOLIDATE WITH LOW OVER LAKE SUPERIOR...WITH TRAILING COLD
FRONT ACROSS NORTHERN IA EVENTUALLY TO PUSH ACROSS OUR CWA THIS
AFTERNOON AND GUSTY SOUTHWEST WINDS TO SHIFT WEST. BASED ON SFC OB
TRENDS WITH TEMPS MAINLY IN THE UPPER TEENS UPSTREAM HAVE SHAVED A
COUPLE OF DEGREES OFF OF MAX TEMPS MAINLY ACROSS SOUTHERN CWA.
OTHERWISE...EXCEPT FOR SOME TWEAKS TO SKY COVER GRIDS BASED ON
CURRENT SATELLITE DATA...HAVE MADE NO OTHER CHANGES TO GOING
FORECAST.
RATZER
//PREV DISCUSSION...
329 AM CST
CLICKING MY HEELS THREE TIMES AND CHANTING THERE`S NO PLACE LIKE
CHICAGO IN THE SUMMER HAS YET TO PRODUCE THE DESIRED RESULTS.
FORECAST CHALLENGES THIS MORNING INCLUDE THE POTENTIALLY HIGH IMPACT
LIGHT/MODERATE SNOW LATE TONIGHT/WED MORNING...BITTERLY COLD
TEMPS/WIND CHILLS WED PM INTO WED NIGHT...THEN THE NEXT POTENTIAL
SNOW MAKER FRIDAY NIGHT INTO THE START OF THE WEEKEND.
TEMPS WILL MODERATE PRETTY QUICKLY FROM THE BITTERLY COLD START THIS
MORNING WITH TEMPS REBOUNDING INTO THE TEENS...BUT THE RISE IN TEMPS
WILL BE OFFSET BY THE INCREASINGLY STRONG WINDS WHICH WILL HOLD WIND
CHILLS TO NEAR OR BELOW ZERO MUCH OF THE DAY. WATER VAPOR IMAGERY
SHOWS WELL DEFINED SHORTWAVE DIGGING ESE ACROSS MINNESOTA THIS
MORNING WITH SOME SNOW SHOWERS ASSOCIATED WITH THIS FEATURE ACROSS
MN INT NORTHERN IOWA. TYPICALLY NOT TOO DIFFICULT TO SQUEEZE SNOW
OUT OF AN AIR MASS THIS COLD...SO AS THE SHORTWAVE PIVOTS EAST THIS
MORNING COULD BE SOME SNOW SHOWERS ACROSS MAINLY NORTHERN PORTIONS
OF OUR CWA. THE STRONG WEST WINDS COULD RESULT IN SOME BLOWING AND
DRIFTING SNOW THIS AFTERNOON IN OPEN AREAS.
NEXT SHORTWAVE IN THE HOPPER DIVING SOUTH INTO THE NORTHERN ROCKIES
WILL QUICKLY TRANSLATE EASTWARD TOWARD THE MIDWEST BY LATE TONIGHT
INTO TOMORROW MORNING. STRENGTHENING LOW AND MID LEVEL FRONTOGENESIS
IN ADVANCE OF THIS SHORTWAVE COMBINED WITH BACKING WINDS IN THE
270-285K PRESSURE SURFACE WILL RESULT IN INCREASING LOWER
TROPOSPHERIC ASCENT...WHILE 150KT 300MB JET STREAK IS PROGGED TO
DEVELOP RESULTING IN INCREASING DIVERGENCE ALOFT SETTING THE STAGE
FOR A PRETTY IMPRESSIVE AREA OF SNOW DEVELOPING WITH THIS WAVE.
FAIRLY DEEP DENDRITIC GROWTH ZONE (5000FT+) CO-LOCATED WITH THE
ASCENT COULD ALLOW FOR A PRETTY FLUFFY/HIGH RATIO SNOW. UNLIKE THE
LAST SYSTEM...DEPTH OF THE MOISTURE AND SATURATION IS GREATER AND
EXTENDS WELL ABOVE THE -20C LEVEL...SO SUSPECT THAT THIS SYSTEM WILL
PRODUCE A HIGHER SNL RATIO...LIKELY AT LEAST 15-20:1. GUIDANCE
COMING INTO PRETTY GOOD AGREEMENT ON THE AXIS OF HIGHEST QPF SETTING
UP IN THE I-80 TO I88/290 CORRIDOR WHERE IT`S LOOKING PRETTY LIKELY
THAT A SWATH OF 2 TO LOCALLY 4 INCHES OF SNOW WILL FALL. SNOW LOOKS
TO PEAK IN THE 07-13Z TIME FRAME WESTERN CWA AND 09-15Z OVER CHICAGO
AREA...COINCIDING WITH RUSH HOUR. IN ADDITION TO THE HORRIBLE
TIMING...ANOTHER FACTOR TO MAKE THIS A HIGHER IMPACT EVENT IS THE
COLD AIR TEMPS WHICH WILL RESULT IN UNTREATED SALT BEING LESS
EFFECTIVE ALONG WITH VERY COLD PAVEMENT TEMPS ALSO ADDING TO THE
CHALLENGE FOR ROAD CREWS. WHILE FORECAST SNOWFALL AMOUNTS FALL A
LITTLE SHY OF ADVISORY CRITERIA...THE POTENTIAL FOR THIS TO BE SUCH
A HIGH IMPACT EVENT SEEMS TO JUSTIFY A WINTER WEATHER ADVISORY. PLAN
TO ISSUE IT FOR THE CORRIDOR THAT LOOKS MOST LIKELY TO GET THE
HIGHEST IMPACTS...IT IS POSSIBLE THE DAY SHIFT MAY NEED TO EXPAND
THE AREAL COVERAGE OF THE ADVISORY A BIT...BUT WANTED TO DRAW EARLY
ATTENTION TO THIS POTENTIALLY VERY PROBLEMATIC EVENT.
RE-ENFORCING BLAST OF ARCTIC AIR COMES RUSHING INTO THE AREA
WEDNESDAY AFTERNOON IN THE WAKE OF THE SNOW. TEMPERATURES WILL
LIKELY FALL INTO THE SINGLE DIGITS BY EVENING OVER MOST OF THE AREA
WITH TEMPS POSSIBLY DROPPING BELOW ZERO NORTHWEST CWA BY SUNSET.
STRONG NORTHWEST WINDS WILL RESULT IN WIND CHILLS PLUMMETING WELL
BELOW ZERO...LIKELY 10-20 BELOW BY LATE WEDNESDAY AFTERNOON...THEN
POSSIBLY AS COLD AS 15-30 BELOW ZERO WEDNESDAY NIGHT. LOW TEMPS WILL
BE TRICKY WITH PRESSURE GRADIENT LIKELY TO MAINTAIN SOME WIND
THROUGH THE NIGHT. IN ADDITION...BACKING WINDS LATE AT NIGHT AND
DEVELOPING WARM AIR ADVECTION (MAINLY ALOFT) WITH THE POTENTIAL FOR
CLOUDINESS MOVING IN COULD RESULT IN KEEPING TEMPS FROM GETTING TOO
OUT OF CONTROL. WOULDN`T BE HARD TO ENVISION LATE EVENING LOWS OF
10-15 BELOW IN THE COLDEST LOCATIONS ASSUMING CLOUDS DON`T MAKE AN
EARLY ARRIVAL...BUT THE BUST POTENTIAL WITH LOWS IS HIGH IN BOTH
DIRECTIONS WITH CURRENT FORECAST PROBABLY THE MID RANGE OF THE
POSSIBILITIES. TEMPS SHOULD LEVEL OFF AND POSSIBLY RISE LATE AT
NIGHT AS CLOUDINESS AND WARM AIR ADVECTION INCREASE.
SOME MODERATION IN TEMPS IS EXPECTED THURSDAY WITH CLOUDINESS AND
SOUTHERLY WINDS LIKELY TO RESULT IN NEAR STEADY TEMPS THURSDAY
NIGHT. LOOKS LIKE THINGS COULD GET UNSETTLED WITH ANOTHER CHANCE OF
SNOW FRIDAY NIGHT INTO THE WEEKEND...BUT FORECAST CONFIDENCE IS LOW
AT MEDIUM RANGE MODELS ARE ATTEMPTING TO RESOLVE A VERY COMPLEX
EVOLUTION OF SHORTWAVES. FIRST...A CUT OFF LOW MEANDERING OFF THE
SOUTHERN CALIFORNIA COAST IS PROGGED TO DRIFT EASTWARD INTO THE FOUR
CORNERS REGION BEFORE A NORTHERN STREAM SHORTWAVE DIVES SOUTHEAST
AND CAUSES THE UPPER LOW TO OPEN UP AND BEGIN TO LIFT OUT INTO THE
SOUTHERN PLAINS. BY THE WEEKEND THE MODELS ARE ATTEMPTING TO DEPICT
SOME DEGREE OF PHASING BETWEEN THESE TWO SHORTWAVES WITH A POLAR JET
SHORTWAVE DIGGING SOUTH INTO THE UPPER MISSISSIPPI VALLEY REGION.
MEDIUM RANGE MODELS TEND TO PHASE SHORTWAVES TOO MUCH AND THE RANGE
OF POSSIBILITIES FOR THIS WEEKEND SYSTEM IS STILL VERY LARGE SO IT
IS FAR TOO SOON TO SOUND ANY ALARMS. ANYTIME YOU HAVE A SOUTHWEST
UPPER LOW LIFTING OUT AND POTENTIALLY AFFECTING THE AREA IT IS A
SITUATION THAT REQUIRES MONITORING. ANOTHER LOBE OF ARCTIC AIR IS
CURRENTLY PROGGED TO SPREAD SOUTH INTO THE AREA BEHIND THIS SYSTEM
BUT MODELS DISAGREE ON JUST HOW COLD...SO STAY TUNED.
IZZI
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 20Z...
* WEST WINDS GUSTING TO ABOUT 30KT UNTIL DARK.
* SNOW START TIME OVERNIGHT AND END TIME WEDNESDAY MORNING.
* TIMING OF PEAK SNOWFALL INTENSITY...WITH VSBY OCCASIONALLY DOWN
TO 1/2SM AND CIGS 1000-1500 FT TO POSSIBLY IFR.
RC
//DISCUSSION...UPDATED 18Z...
THE PRIMARY AVIATION CONCERN IS WITH A CLIPPER TYPE SYSTEM THAT
WILL BRING A PERIOD OF ACCUMULATING SNOWFALL TO THE TERMINALS
OVERNIGHT INTO EARLY WEDNESDAY MORNING.
THROUGH THE REMAINDER OF THE DAY...EXPECT PRIMARILY VFR...THOUGH
THERE COULD BE OCCASIONAL FLURRIES AND BRIEF HIGH MVFR CIGS.
WESTERLY WINDS WILL GUST UP TO 30 KT OR SO UNTIL DIMINISHING WITH
NIGHTFALL. WINDS WILL FURTHER DIMINISH WITH APPROACH OF LOW
PRESSURE SYSTEM OVERNIGHT.
DECENT AGREEMENT IN THE GUIDANCE WITH START TIME AROUND MIDNIGHT
NEAR RFD AND 1 TO 2 HOURS LATER FOR THE EASTERN TERMINALS...WITH
VSBY QUICKLY DROPPING TO ABOUT 1 MILE AND LOW MVFR CIGS. EXPECTING
ABOUT A 3 HOUR PERIOD WITH OCCASIONAL MODERATE SNOWFALL RATES UP
TO 1/2 INCH PER HOUR. FOR THE CHICAGO TERMINALS...CURRENT
INDICATIONS FAVOR PEAK INTENSITY BETWEEN 9 AND 12 UTC...THOUGH
TIMING MAY NEED SOME MINOR ADJUSTMENTS. DURING THIS TIME...VSBY
COULD DROP TO 1/2SM WITH CIGS POSSIBLY FALLING TO IFR. THE SNOW
WILL TAPER OFF BY ABOUT SUNRISE NEAR RFD AND MID MORNING TO THE
EAST. AFTER THE SNOW ENDS...MID TO HIGH MVFR CIGS SHOULD SCATTER
OUT BY DARK. WINDS WILL SHIFT TO NORTHWEST AND COULD GUST UP TO 20
TO 25 KT.
TOTAL SNOWFALL ACCUMULATIONS WITH THE SYSTEM ARE EXPECTED TO
RANGE BETWEEN 2 AND 3 INCHES. DUE TO VERY COLD TEMPERATURES...THE
SNOW WILL BE VERY LIGHT AND FLUFFY AND CONDUCIVE TO SLICK RUNWAY
CONDITIONS.
RC
//ORD AND MDW CONFIDENCE...UPDATED 20Z...
* HIGH FOR WIND FORECAST.
* MEDIUM FOR SNOW START TIME OF 08Z AND ENDING BY 15Z.
* MEDIUM FOR PEAK INTENSITY BETWEEN 9Z-12Z.
* HIGH FOR IFR VSBY WITH SNOW...MEDIUM FOR OCCASIONAL 1/2SM VSBY.
* MEDIUM FOR 1000 TO 1500 FT CIGS WITH SNOW...LOW FOR IFR CIGS.
RC
//OUTLOOK FOR ORD/MDW FOR 00Z THURSDAY-12Z TUESDAY...UPDATED 12Z...
WEDNESDAY NIGHT...VFR.
THURSDAY...VFR.
FRIDAY...CHC SNOW...ESPECIALLY LATE. MVFR/IFR PSBL.
SATURDAY...SNOW LIKELY. IFR.
SUNDAY...CHC SNOW. IMPROVING TO VFR.
MONDAY...VFR.
BMD
&&
.MARINE...
145 PM CST
MARINE FORECAST CONCERNS IN ACTIVE PATTERN INCLUDE ONGOING WESTERLY
GALES INTO TONIGHT...THEN AN EXTENDED PERIOD OF WEST-NORTHWEST WINDS
25-30 KT INTO THURSDAY AS ANOTHER ARCTIC HIGH BUILDS THROUGH THE
OHIO VALLEY IN THE WAKE OF ANOTHER CLIPPER. WINDS SHIFT NORTH LATE
THURSDAY NIGHT AS A COLD FRONT SETTLES SOUTH AFTER ANOTHER LOW
PASSES NORTH OF THE LAKES.
LOW PRESSURE WAS LIFTING NORTHEAST ACROSS EASTERN LAKE SUPERIOR THIS
AFTERNOON...WITH A COLD FRONT TRAILING ACROSS WISCONSIN AND FAR
NORTHWEST ILLINOIS. TIGHTENING OF THE GRADIENT IN ASSOCIATION WITH
THE LOW...AND WITH THE PRESSURE RISE/FALL COUPLET WITH THE LOW AND
APPROACHING FRONT HAS RESULTED IN WEST-SOUTHWEST GALES ACROSS THE
SOUTHERN 1/2 OR SO OF LAKE MICHIGAN. WINDS WILL INCREASE THROUGH
LATE AFTERNOON ACROSS NORTHERN LAKE MICHIGAN AS WELL...AS THE LOW
PULLS AWAY TO THE NORTHEAST. FORECAST SOUNDINGS INDICATE THAT GALES
WILL BE A LITTLE MORE MARGINAL ACROSS NORTHERN LAKE MICHIGAN THAN
THEY WERE EARLIER ACROSS THE SOUTH PART OF THE LAKE...WHERE 40+ KT
WINDS OCCURRED DURING THE MID/LATE MORNING HOURS. WEAK HIGH PRESSURE
RIDGING WILL DEVELOP ACROSS THE LAKE TONIGHT...ALLOWING WINDS TO
DECREASE SOMEWHAT...THOUGH THE MAIN HIGH WILL REMAIN WELL TO THE
SOUTH ACROSS THE OHIO VALLEY. THUS A WEST-NORTHWEST GRADIENT WILL
REMAIN ACROSS THE LAKE WHICH WILL CONTINUE TO SUPPORT WESTERLY 25-30
KT WINDS.
A WEAK LOW WILL MOVE QUICKLY ACROSS THE MIDWEST SOUTH OF THE LAKES
WEDNESDAY...WHICH WILL ALLOW A BRIEF DECREASE IN WINDS ACROSS FAR
SOUTHERN LAKE MICHGAN DURING THE MORNING...THOUGH COLD ARCTIC HIGH
PRESSURE WILL BUILD QUICKLY FROM THE PLAINS INTO THE OHIO VALLEY
WEDNESDAY AFTERNOON AND NIGHT WHICH WILL TIGHTEN UP THE GRADIENT
AGAIN ACROSS THE LAKES. THIS HIGH WILL SLOWLY DRIFT THROUGH AND
SOUTH OF THE OHIO VALLEY THROUGH FRIDAY...WHILE ANOTHER LOW PASSES
NORTH OF THE LAKES. THIS LOW WILL TRAIL A COLD FRONT DOWN THE LAKE
THURSDAY NIGHT...SHIFTING WINDS TO THE NORTH-NORTHEAST FRIDAY.
EAST-NORTHEAST WINDS WILL THEN CONTINUE INTO THE WEEKEND AS YET
ANOTHER LOW/INVERTED TROUGH DEVELOPS ACROSS THE LOWER MISSISSIPPI
AND OHIO VALLEYS.
RATZER
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...WINTER WEATHER ADVISORY...ILZ008-ILZ010-ILZ011-ILZ012-ILZ013-
ILZ014-ILZ019-ILZ020-ILZ021-ILZ022...MIDNIGHT WEDNESDAY TO
10 AM WEDNESDAY.
IN...WINTER WEATHER ADVISORY...INZ001-INZ002...MIDNIGHT WEDNESDAY TO
10 AM WEDNESDAY.
LM...GALE WARNING...LMZ080-LMZ567-LMZ669-LMZ671-LMZ673-LMZ675-LMZ740-
LMZ741-LMZ742-LMZ743-LMZ744-LMZ745-LMZ777-LMZ779-LMZ868-
LMZ870-LMZ872-LMZ874-LMZ876-LMZ878 UNTIL 9 PM TUESDAY.
GALE WARNING...LMZ261-LMZ362-LMZ364-LMZ366-LMZ563-LMZ565 UNTIL 3
AM WEDNESDAY.
&&
$$
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
1134 AM CST TUE DEC 10 2013
.DISCUSSION...
947 AM CST
FOR MORNING UPDATE...
ONLY MINOR EDITS TO MORNING GRIDS/FORECASTS BASED ON CURRENT
OBSERVATIONAL DATA. HAVE ENDED SNOW SHOWERS AND REPLACED WITH
SCATTERED FLURRIES ACROSS NORTH CENTRAL IL THROUGH LATE MORNING AND
LOWERED HIGH TEMPS A COUPLE OF DEGREES ESPECIALLY SOUTH.
MORNING GOES VAPOR IMAGERY AND RAP INITIALIZATION OF UPPER AIR DATA
DEPICTS MID-LEVEL SHORT WAVE TROUGH MOVING ACROSS THE FORECAST AREA
AT MID-MORNING. AREA OF LIGHT SNOW/SNOW SHOWERS ASSOCIATED WITH THIS
DISTURBANCE WAS MOVING EAST ACROSS THE CWA...MAINLY THE IMMEDIATE
CHICAGO AREA AND ADJACENT NORTHWEST INDIANA/SOUTHERN LAKE MICHIGAN.
A FEW FLURRIES LINGERING BACK ACROSS PARTS OF NORTH CENTRAL IL...
WITH SKIES OTHERWISE BECOMING PARTLY CLOUDY/MOSTLY SUNNY FROM THE
WEST AS THE MID LEVEL WAVE CONTINUES TO TRACK OFF TO THE EAST
THROUGH MID-DAY. AT THE SURFACE...WEAK SURFACE LOW OVER WI PROGGED
TO CONSOLIDATE WITH LOW OVER LAKE SUPERIOR...WITH TRAILING COLD
FRONT ACROSS NORTHERN IA EVENTUALLY TO PUSH ACROSS OUR CWA THIS
AFTERNOON AND GUSTY SOUTHWEST WINDS TO SHIFT WEST. BASED ON SFC OB
TRENDS WITH TEMPS MAINLY IN THE UPPER TEENS UPSTREAM HAVE SHAVED A
COUPLE OF DEGREES OFF OF MAX TEMPS MAINLY ACROSS SOUTHERN CWA.
OTHERWISE...EXCEPT FOR SOME TWEAKS TO SKY COVER GRIDS BASED ON
CURRENT SATELLITE DATA...HAVE MADE NO OTHER CHANGES TO GOING
FORECAST.
RATZER
//PREV DISCUSSION...
329 AM CST
CLICKING MY HEELS THREE TIMES AND CHANTING THERE`S NO PLACE LIKE
CHICAGO IN THE SUMMER HAS YET TO PRODUCE THE DESIRED RESULTS.
FORECAST CHALLENGES THIS MORNING INCLUDE THE POTENTIALLY HIGH IMPACT
LIGHT/MODERATE SNOW LATE TONIGHT/WED MORNING...BITTERLY COLD
TEMPS/WIND CHILLS WED PM INTO WED NIGHT...THEN THE NEXT POTENTIAL
SNOW MAKER FRIDAY NIGHT INTO THE START OF THE WEEKEND.
TEMPS WILL MODERATE PRETTY QUICKLY FROM THE BITTERLY COLD START THIS
MORNING WITH TEMPS REBOUNDING INTO THE TEENS...BUT THE RISE IN TEMPS
WILL BE OFFSET BY THE INCREASINGLY STRONG WINDS WHICH WILL HOLD WIND
CHILLS TO NEAR OR BELOW ZERO MUCH OF THE DAY. WATER VAPOR IMAGERY
SHOWS WELL DEFINED SHORTWAVE DIGGING ESE ACROSS MINNESOTA THIS
MORNING WITH SOME SNOW SHOWERS ASSOCIATED WITH THIS FEATURE ACROSS
MN INT NORTHERN IOWA. TYPICALLY NOT TOO DIFFICULT TO SQUEEZE SNOW
OUT OF AN AIR MASS THIS COLD...SO AS THE SHORTWAVE PIVOTS EAST THIS
MORNING COULD BE SOME SNOW SHOWERS ACROSS MAINLY NORTHERN PORTIONS
OF OUR CWA. THE STRONG WEST WINDS COULD RESULT IN SOME BLOWING AND
DRIFTING SNOW THIS AFTERNOON IN OPEN AREAS.
NEXT SHORTWAVE IN THE HOPPER DIVING SOUTH INTO THE NORTHERN ROCKIES
WILL QUICKLY TRANSLATE EASTWARD TOWARD THE MIDWEST BY LATE TONIGHT
INTO TOMORROW MORNING. STRENGTHENING LOW AND MID LEVEL FRONTOGENESIS
IN ADVANCE OF THIS SHORTWAVE COMBINED WITH BACKING WINDS IN THE
270-285K PRESSURE SURFACE WILL RESULT IN INCREASING LOWER
TROPOSPHERIC ASCENT...WHILE 150KT 300MB JET STREAK IS PROGGED TO
DEVELOP RESULTING IN INCREASING DIVERGENCE ALOFT SETTING THE STAGE
FOR A PRETTY IMPRESSIVE AREA OF SNOW DEVELOPING WITH THIS WAVE.
FAIRLY DEEP DENDRITIC GROWTH ZONE (5000FT+) CO-LOCATED WITH THE
ASCENT COULD ALLOW FOR A PRETTY FLUFFY/HIGH RATIO SNOW. UNLIKE THE
LAST SYSTEM...DEPTH OF THE MOISTURE AND SATURATION IS GREATER AND
EXTENDS WELL ABOVE THE -20C LEVEL...SO SUSPECT THAT THIS SYSTEM WILL
PRODUCE A HIGHER SNL RATIO...LIKELY AT LEAST 15-20:1. GUIDANCE
COMING INTO PRETTY GOOD AGREEMENT ON THE AXIS OF HIGHEST QPF SETTING
UP IN THE I-80 TO I88/290 CORRIDOR WHERE IT`S LOOKING PRETTY LIKELY
THAT A SWATH OF 2 TO LOCALLY 4 INCHES OF SNOW WILL FALL. SNOW LOOKS
TO PEAK IN THE 07-13Z TIME FRAME WESTERN CWA AND 09-15Z OVER CHICAGO
AREA...COINCIDING WITH RUSH HOUR. IN ADDITION TO THE HORRIBLE
TIMING...ANOTHER FACTOR TO MAKE THIS A HIGHER IMPACT EVENT IS THE
COLD AIR TEMPS WHICH WILL RESULT IN UNTREATED SALT BEING LESS
EFFECTIVE ALONG WITH VERY COLD PAVEMENT TEMPS ALSO ADDING TO THE
CHALLENGE FOR ROAD CREWS. WHILE FORECAST SNOWFALL AMOUNTS FALL A
LITTLE SHY OF ADVISORY CRITERIA...THE POTENTIAL FOR THIS TO BE SUCH
A HIGH IMPACT EVENT SEEMS TO JUSTIFY A WINTER WEATHER ADVISORY. PLAN
TO ISSUE IT FOR THE CORRIDOR THAT LOOKS MOST LIKELY TO GET THE
HIGHEST IMPACTS...IT IS POSSIBLE THE DAY SHIFT MAY NEED TO EXPAND
THE AREAL COVERAGE OF THE ADVISORY A BIT...BUT WANTED TO DRAW EARLY
ATTENTION TO THIS POTENTIALLY VERY PROBLEMATIC EVENT.
RE-ENFORCING BLAST OF ARCTIC AIR COMES RUSHING INTO THE AREA
WEDNESDAY AFTERNOON IN THE WAKE OF THE SNOW. TEMPERATURES WILL
LIKELY FALL INTO THE SINGLE DIGITS BY EVENING OVER MOST OF THE AREA
WITH TEMPS POSSIBLY DROPPING BELOW ZERO NORTHWEST CWA BY SUNSET.
STRONG NORTHWEST WINDS WILL RESULT IN WIND CHILLS PLUMMETING WELL
BELOW ZERO...LIKELY 10-20 BELOW BY LATE WEDNESDAY AFTERNOON...THEN
POSSIBLY AS COLD AS 15-30 BELOW ZERO WEDNESDAY NIGHT. LOW TEMPS WILL
BE TRICKY WITH PRESSURE GRADIENT LIKELY TO MAINTAIN SOME WIND
THROUGH THE NIGHT. IN ADDITION...BACKING WINDS LATE AT NIGHT AND
DEVELOPING WARM AIR ADVECTION (MAINLY ALOFT) WITH THE POTENTIAL FOR
CLOUDINESS MOVING IN COULD RESULT IN KEEPING TEMPS FROM GETTING TOO
OUT OF CONTROL. WOULDN`T BE HARD TO ENVISION LATE EVENING LOWS OF
10-15 BELOW IN THE COLDEST LOCATIONS ASSUMING CLOUDS DON`T MAKE AN
EARLY ARRIVAL...BUT THE BUST POTENTIAL WITH LOWS IS HIGH IN BOTH
DIRECTIONS WITH CURRENT FORECAST PROBABLY THE MID RANGE OF THE
POSSIBILITIES. TEMPS SHOULD LEVEL OFF AND POSSIBLY RISE LATE AT
NIGHT AS CLOUDINESS AND WARM AIR ADVECTION INCREASE.
SOME MODERATION IN TEMPS IS EXPECTED THURSDAY WITH CLOUDINESS AND
SOUTHERLY WINDS LIKELY TO RESULT IN NEAR STEADY TEMPS THURSDAY
NIGHT. LOOKS LIKE THINGS COULD GET UNSETTLED WITH ANOTHER CHANCE OF
SNOW FRIDAY NIGHT INTO THE WEEKEND...BUT FORECAST CONFIDENCE IS LOW
AT MEDIUM RANGE MODELS ARE ATTEMPTING TO RESOLVE A VERY COMPLEX
EVOLUTION OF SHORTWAVES. FIRST...A CUT OFF LOW MEANDERING OFF THE
SOUTHERN CALIFORNIA COAST IS PROGGED TO DRIFT EASTWARD INTO THE FOUR
CORNERS REGION BEFORE A NORTHERN STREAM SHORTWAVE DIVES SOUTHEAST
AND CAUSES THE UPPER LOW TO OPEN UP AND BEGIN TO LIFT OUT INTO THE
SOUTHERN PLAINS. BY THE WEEKEND THE MODELS ARE ATTEMPTING TO DEPICT
SOME DEGREE OF PHASING BETWEEN THESE TWO SHORTWAVES WITH A POLAR JET
SHORTWAVE DIGGING SOUTH INTO THE UPPER MISSISSIPPI VALLEY REGION.
MEDIUM RANGE MODELS TEND TO PHASE SHORTWAVES TOO MUCH AND THE RANGE
OF POSSIBILITIES FOR THIS WEEKEND SYSTEM IS STILL VERY LARGE SO IT
IS FAR TOO SOON TO SOUND ANY ALARMS. ANYTIME YOU HAVE A SOUTHWEST
UPPER LOW LIFTING OUT AND POTENTIALLY AFFECTING THE AREA IT IS A
SITUATION THAT REQUIRES MONITORING. ANOTHER LOBE OF ARCTIC AIR IS
CURRENTLY PROGGED TO SPREAD SOUTH INTO THE AREA BEHIND THIS SYSTEM
BUT MODELS DISAGREE ON JUST HOW COLD...SO STAY TUNED.
IZZI
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 18Z...
* WEST WINDS GUSTING TO ABOUT 30KT UNTIL DARK.
* SNOW START TIME OVERNIGHT AND END TIME WEDNESDAY MORNING.
* TIMING OF PEAK SNOWFALL INTENSITY...WITH VSBY OCCASIONALLY DOWN
TO 1/2SM AND CIGS 1000-1500 FT TO POSSIBLY IFR.
RC
//DISCUSSION...UPDATED 18Z...
THE PRIMARY AVIATION CONCERN IS WITH A CLIPPER TYPE SYSTEM THAT
WILL BRING A PERIOD OF ACCUMULATING SNOWFALL TO THE TERMINALS
OVERNIGHT INTO EARLY WEDNESDAY MORNING.
THROUGH THE REMAINDER OF THE DAY...EXPECT PRIMARILY VFR...THOUGH
THERE COULD BE OCCASIONAL FLURRIES AND BRIEF HIGH MVFR CIGS.
WESTERLY WINDS WILL GUST UP TO 30 KT OR SO UNTIL DIMINISHING WITH
NIGHTFALL. WINDS WILL FURTHER DIMINISH WITH APPROACH OF LOW
PRESSURE SYSTEM OVERNIGHT.
DECENT AGREEMENT IN THE GUIDANCE WITH START TIME AROUND MIDNIGHT
NEAR RFD AND 1 TO 2 HOURS LATER FOR THE EASTERN TERMINALS...WITH
VSBY QUICKLY DROPPING TO ABOUT 1 MILE AND LOW MVFR CIGS. EXPECTING
ABOUT A 3 HOUR PERIOD WITH OCCASIONAL MODERATE SNOWFALL RATES UP
TO 1/2 INCH PER HOUR. FOR THE CHICAGO TERMINALS...CURRENT
INDICATIONS FAVOR PEAK INTENSITY BETWEEN 9 AND 12 UTC...THOUGH
TIMING MAY NEED SOME MINOR ADJUSTMENTS. DURING THIS TIME...VSBY
COULD DROP TO 1/2SM WITH CIGS POSSIBLY FALLING TO IFR. THE SNOW
WILL TAPER OFF BY ABOUT SUNRISE NEAR RFD AND MID MORNING TO THE
EAST. AFTER THE SNOW ENDS...MID TO HIGH MVFR CIGS SHOULD SCATTER
OUT BY DARK. WINDS WILL SHIFT TO NORTHWEST AND COULD GUST UP TO 20
TO 25 KT.
TOTAL SNOWFALL ACCUMULATIONS WITH THE SYSTEM ARE EXPECTED TO
RANGE BETWEEN 2 AND 3 INCHES. DUE TO VERY COLD TEMPERATURES...THE
SNOW WILL BE VERY LIGHT AND FLUFFY AND CONDUCIVE TO SLICK RUNWAY
CONDITIONS.
RC
//ORD AND MDW CONFIDENCE...UPDATED 18Z...
* HIGH FOR WIND FORECAST.
* MEDIUM FOR SNOW START TIME OF 08Z AND ENDING BY 15Z.
* MEDIUM FOR PEAK INTENSITY BETWEEN 9Z-12Z.
* HIGH FOR IFR VSBY WITH SNOW...MEDIUM FOR OCCASIONAL 1/2SM VSBY.
* MEDIUM FOR 1000 TO 1500 FT CIGS WITH SNOW...LOW FOR IFR CIGS.
RC
//OUTLOOK FOR ORD/MDW FOR 00Z THURSDAY-12Z TUESDAY...UPDATED 12Z...
WEDNESDAY NIGHT...VFR.
THURSDAY...VFR.
FRIDAY...CHC SNOW...ESPECIALLY LATE. MVFR/IFR PSBL.
SATURDAY...SNOW LIKELY. IFR.
SUNDAY...CHC SNOW. IMPROVING TO VFR.
MONDAY...VFR.
BMD
&&
.MARINE...
324 AM CST
TRANSIENT RIDGE IS MOVING ACROSS THE LAKE EARLY THIS MORNING
ALLOWING WINDS OT BRIEFLY TAPER...AND WILL ALLOW THE FIRST GALE
WARNING TO EXPIRE THIS MORNING FOR THE NORTH HALF OF THE LAKE. THE
RESPITE WILL BE SHORT LIVED HOWEVER AS A CLIPPER SYSTEM WILL MOVE
ACROSS LAKE SUPERIOR THIS AFTERNOON WITH SOUTHWEST WINDS QUICKLY
INCREASING BACK TO GALES ACROSS THE SOUTH HALF OF THE LAKE BY MID
MORNING AHEAD OF THE SYSTEM. WINDS TURN WESTERLY BY MID AFTERNOON
AND THE GALES ARE EXPECTED TO SPREAD TO THE NORTHERN PORTIONS OF
LAKE MICHIGAN. A GALE WARNING REMAINS IN EFFECT FOR THE ENTIRE LAKE
FOR THIS SYSTEM. YET ANOTHER CLIPPER SYSTEM WILL MOVE ACROSS LAKE
MICHIGAN LATE TONIGHT AND EARLY WEDNESDAY. EXPECT WINDS TO TOP OUT
JUST BELOW GALES THOUGH...AROUND 30 KT. WINDS WILL REMAIN BREEZY
THROUGH THE REMAINDER OF THE WEEK AND INTO THE WEEKEND.
BMD
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...WINTER WEATHER ADVISORY...ILZ008-ILZ010-ILZ011-ILZ012-ILZ013-
ILZ014-ILZ019-ILZ020-ILZ021-ILZ022...MIDNIGHT WEDNESDAY TO
10 AM WEDNESDAY.
IN...WINTER WEATHER ADVISORY...INZ001-INZ002...MIDNIGHT WEDNESDAY TO
10 AM WEDNESDAY.
LM...GALE WARNING...LMZ080-LMZ567-LMZ669-LMZ671-LMZ673-LMZ675-LMZ740-
LMZ741-LMZ742-LMZ743-LMZ744-LMZ745-LMZ777-LMZ779-LMZ868-
LMZ870-LMZ872-LMZ874-LMZ876-LMZ878 UNTIL 9 PM TUESDAY.
GALE WARNING...LMZ261-LMZ362-LMZ364-LMZ366-LMZ563-LMZ565...4 PM
TUESDAY TO 3 AM WEDNESDAY.
&&
$$
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
959 AM CST TUE DEC 10 2013
.DISCUSSION...
947 AM CST
FOR MORNING UPDATE...
ONLY MINOR EDITS TO MORNING GRIDS/FORECASTS BASED ON CURRENT
OBSERVATIONAL DATA. HAVE ENDED SNOW SHOWERS AND REPLACED WITH
SCATTERED FLURRIES ACROSS NORTH CENTRAL IL THROUGH LATE MORNING AND
LOWERED HIGH TEMPS A COUPLE OF DEGREES ESPECIALLY SOUTH.
MORNING GOES VAPOR IMAGERY AND RAP INITIALIZATION OF UPPER AIR DATA
DEPICTS MID-LEVEL SHORT WAVE TROUGH MOVING ACROSS THE FORECAST AREA
AT MID-MORNING. AREA OF LIGHT SNOW/SNOW SHOWERS ASSOCIATED WITH THIS
DISTURBANCE WAS MOVING EAST ACROSS THE CWA...MAINLY THE IMMEDIATE
CHICAGO AREA AND ADJACENT NORTHWEST INDIANA/SOUTHERN LAKE MICHIGAN.
A FEW FLURRIES LINGERING BACK ACROSS PARTS OF NORTH CENTRAL IL...
WITH SKIES OTHERWISE BECOMING PARTLY CLOUDY/MOSTLY SUNNY FROM THE
WEST AS THE MID LEVEL WAVE CONTINUES TO TRACK OFF TO THE EAST
THROUGH MID-DAY. AT THE SURFACE...WEAK SURFACE LOW OVER WI PROGGED
TO CONSOLIDATE WITH LOW OVER LAKE SUPERIOR...WITH TRAILING COLD
FRONT ACROSS NORTHERN IA EVENTUALLY TO PUSH ACROSS OUR CWA THIS
AFTERNOON AND GUSTY SOUTHWEST WINDS TO SHIFT WEST. BASED ON SFC OB
TRENDS WITH TEMPS MAINLY IN THE UPPER TEENS UPSTREAM HAVE SHAVED A
COUPLE OF DEGREES OFF OF MAX TEMPS MAINLY ACROSS SOUTHERN CWA.
OTHERWISE...EXCEPT FOR SOME TWEAKS TO SKY COVER GRIDS BASED ON
CURRENT SATELLITE DATA...HAVE MADE NO OTHER CHANGES TO GOING
FORECAST.
RATZER
//PREV DISCUSSION...
329 AM CST
CLICKING MY HEELS THREE TIMES AND CHANTING THERE`S NO PLACE LIKE
CHICAGO IN THE SUMMER HAS YET TO PRODUCE THE DESIRED RESULTS.
FORECAST CHALLENGES THIS MORNING INCLUDE THE POTENTIALLY HIGH IMPACT
LIGHT/MODERATE SNOW LATE TONIGHT/WED MORNING...BITTERLY COLD
TEMPS/WIND CHILLS WED PM INTO WED NIGHT...THEN THE NEXT POTENTIAL
SNOW MAKER FRIDAY NIGHT INTO THE START OF THE WEEKEND.
TEMPS WILL MODERATE PRETTY QUICKLY FROM THE BITTERLY COLD START THIS
MORNING WITH TEMPS REBOUNDING INTO THE TEENS...BUT THE RISE IN TEMPS
WILL BE OFFSET BY THE INCREASINGLY STRONG WINDS WHICH WILL HOLD WIND
CHILLS TO NEAR OR BELOW ZERO MUCH OF THE DAY. WATER VAPOR IMAGERY
SHOWS WELL DEFINED SHORTWAVE DIGGING ESE ACROSS MINNESOTA THIS
MORNING WITH SOME SNOW SHOWERS ASSOCIATED WITH THIS FEATURE ACROSS
MN INT NORTHERN IOWA. TYPICALLY NOT TOO DIFFICULT TO SQUEEZE SNOW
OUT OF AN AIR MASS THIS COLD...SO AS THE SHORTWAVE PIVOTS EAST THIS
MORNING COULD BE SOME SNOW SHOWERS ACROSS MAINLY NORTHERN PORTIONS
OF OUR CWA. THE STRONG WEST WINDS COULD RESULT IN SOME BLOWING AND
DRIFTING SNOW THIS AFTERNOON IN OPEN AREAS.
NEXT SHORTWAVE IN THE HOPPER DIVING SOUTH INTO THE NORTHERN ROCKIES
WILL QUICKLY TRANSLATE EASTWARD TOWARD THE MIDWEST BY LATE TONIGHT
INTO TOMORROW MORNING. STRENGTHENING LOW AND MID LEVEL FRONTOGENESIS
IN ADVANCE OF THIS SHORTWAVE COMBINED WITH BACKING WINDS IN THE
270-285K PRESSURE SURFACE WILL RESULT IN INCREASING LOWER
TROPOSPHERIC ASCENT...WHILE 150KT 300MB JET STREAK IS PROGGED TO
DEVELOP RESULTING IN INCREASING DIVERGENCE ALOFT SETTING THE STAGE
FOR A PRETTY IMPRESSIVE AREA OF SNOW DEVELOPING WITH THIS WAVE.
FAIRLY DEEP DENDRITIC GROWTH ZONE (5000FT+) CO-LOCATED WITH THE
ASCENT COULD ALLOW FOR A PRETTY FLUFFY/HIGH RATIO SNOW. UNLIKE THE
LAST SYSTEM...DEPTH OF THE MOISTURE AND SATURATION IS GREATER AND
EXTENDS WELL ABOVE THE -20C LEVEL...SO SUSPECT THAT THIS SYSTEM WILL
PRODUCE A HIGHER SNL RATIO...LIKELY AT LEAST 15-20:1. GUIDANCE
COMING INTO PRETTY GOOD AGREEMENT ON THE AXIS OF HIGHEST QPF SETTING
UP IN THE I-80 TO I88/290 CORRIDOR WHERE IT`S LOOKING PRETTY LIKELY
THAT A SWATH OF 2 TO LOCALLY 4 INCHES OF SNOW WILL FALL. SNOW LOOKS
TO PEAK IN THE 07-13Z TIME FRAME WESTERN CWA AND 09-15Z OVER CHICAGO
AREA...COINCIDING WITH RUSH HOUR. IN ADDITION TO THE HORRIBLE
TIMING...ANOTHER FACTOR TO MAKE THIS A HIGHER IMPACT EVENT IS THE
COLD AIR TEMPS WHICH WILL RESULT IN UNTREATED SALT BEING LESS
EFFECTIVE ALONG WITH VERY COLD PAVEMENT TEMPS ALSO ADDING TO THE
CHALLENGE FOR ROAD CREWS. WHILE FORECAST SNOWFALL AMOUNTS FALL A
LITTLE SHY OF ADVISORY CRITERIA...THE POTENTIAL FOR THIS TO BE SUCH
A HIGH IMPACT EVENT SEEMS TO JUSTIFY A WINTER WEATHER ADVISORY. PLAN
TO ISSUE IT FOR THE CORRIDOR THAT LOOKS MOST LIKELY TO GET THE
HIGHEST IMPACTS...IT IS POSSIBLE THE DAY SHIFT MAY NEED TO EXPAND
THE AREAL COVERAGE OF THE ADVISORY A BIT...BUT WANTED TO DRAW EARLY
ATTENTION TO THIS POTENTIALLY VERY PROBLEMATIC EVENT.
RE-ENFORCING BLAST OF ARCTIC AIR COMES RUSHING INTO THE AREA
WEDNESDAY AFTERNOON IN THE WAKE OF THE SNOW. TEMPERATURES WILL
LIKELY FALL INTO THE SINGLE DIGITS BY EVENING OVER MOST OF THE AREA
WITH TEMPS POSSIBLY DROPPING BELOW ZERO NORTHWEST CWA BY SUNSET.
STRONG NORTHWEST WINDS WILL RESULT IN WIND CHILLS PLUMMETING WELL
BELOW ZERO...LIKELY 10-20 BELOW BY LATE WEDNESDAY AFTERNOON...THEN
POSSIBLY AS COLD AS 15-30 BELOW ZERO WEDNESDAY NIGHT. LOW TEMPS WILL
BE TRICKY WITH PRESSURE GRADIENT LIKELY TO MAINTAIN SOME WIND
THROUGH THE NIGHT. IN ADDITION...BACKING WINDS LATE AT NIGHT AND
DEVELOPING WARM AIR ADVECTION (MAINLY ALOFT) WITH THE POTENTIAL FOR
CLOUDINESS MOVING IN COULD RESULT IN KEEPING TEMPS FROM GETTING TOO
OUT OF CONTROL. WOULDN`T BE HARD TO ENVISION LATE EVENING LOWS OF
10-15 BELOW IN THE COLDEST LOCATIONS ASSUMING CLOUDS DON`T MAKE AN
EARLY ARRIVAL...BUT THE BUST POTENTIAL WITH LOWS IS HIGH IN BOTH
DIRECTIONS WITH CURRENT FORECAST PROBABLY THE MID RANGE OF THE
POSSIBILITIES. TEMPS SHOULD LEVEL OFF AND POSSIBLY RISE LATE AT
NIGHT AS CLOUDINESS AND WARM AIR ADVECTION INCREASE.
SOME MODERATION IN TEMPS IS EXPECTED THURSDAY WITH CLOUDINESS AND
SOUTHERLY WINDS LIKELY TO RESULT IN NEAR STEADY TEMPS THURSDAY
NIGHT. LOOKS LIKE THINGS COULD GET UNSETTLED WITH ANOTHER CHANCE OF
SNOW FRIDAY NIGHT INTO THE WEEKEND...BUT FORECAST CONFIDENCE IS LOW
AT MEDIUM RANGE MODELS ARE ATTEMPTING TO RESOLVE A VERY COMPLEX
EVOLUTION OF SHORTWAVES. FIRST...A CUT OFF LOW MEANDERING OFF THE
SOUTHERN CALIFORNIA COAST IS PROGGED TO DRIFT EASTWARD INTO THE FOUR
CORNERS REGION BEFORE A NORTHERN STREAM SHORTWAVE DIVES SOUTHEAST
AND CAUSES THE UPPER LOW TO OPEN UP AND BEGIN TO LIFT OUT INTO THE
SOUTHERN PLAINS. BY THE WEEKEND THE MODELS ARE ATTEMPTING TO DEPICT
SOME DEGREE OF PHASING BETWEEN THESE TWO SHORTWAVES WITH A POLAR JET
SHORTWAVE DIGGING SOUTH INTO THE UPPER MISSISSIPPI VALLEY REGION.
MEDIUM RANGE MODELS TEND TO PHASE SHORTWAVES TOO MUCH AND THE RANGE
OF POSSIBILITIES FOR THIS WEEKEND SYSTEM IS STILL VERY LARGE SO IT
IS FAR TOO SOON TO SOUND ANY ALARMS. ANYTIME YOU HAVE A SOUTHWEST
UPPER LOW LIFTING OUT AND POTENTIALLY AFFECTING THE AREA IT IS A
SITUATION THAT REQUIRES MONITORING. ANOTHER LOBE OF ARCTIC AIR IS
CURRENTLY PROGGED TO SPREAD SOUTH INTO THE AREA BEHIND THIS SYSTEM
BUT MODELS DISAGREE ON JUST HOW COLD...SO STAY TUNED.
IZZI
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 16Z...
* WESTERLY WINDS GUSTING IN EXCESS OF 30 KT THROUGH THIS
AFTERNOON.
* BETTER CHANCES FOR SNOW LATE TONIGHT INTO EARLY WEDNESDAY WHICH
IS EXPECTED TO PRODUCE 2 TO 3 INCHES OF SNOW ACCUMULATION.
BMD/KB
//DISCUSSION...UPDATED 12Z...
A PAIR OF CLIPPERS WILL RACE ACROSS THE AREA IN THE UPCOMING TAF
PERIOD. THE FIRST SYSTEM IS ALREADY PUSHING EAST ACROSS WISCONSIN
WITH A FEW PATCHES OF SNOW DEVELOPING AS FAR SOUTH AS EASTERN IOWA
EARLY THIS MORNING. THIS AREA OF SNOW WILL BE THE MAIN CONCERN THIS
MORNING AS IT WILL TRACK NEAR THE TERMINALS. HAVE INCLUDED TEMPO FOR
SNOW AT RFD...BUT NAM/RAP GUIDANCE WHICH SEEM TO BE INITIALIZING
BEST ON THIS AREA OF SNOW BOTH SUGGEST IT WILL LIFT NORTH OF THE
CHICAGO AREA TERMINALS WHILE DISSIPATING LATER THIS MORNING. IF ON
THE OFF CHANCE IT WERE TO IMPACT THE TERMINALS...WOULD EXPECT VSBY
TO DROP ANYWHERE FROM 1/2SM TO 2SM FOR ABOUT AN HOUR. WINDS WILL BE
VEERING BACK TO THE WEST BY EARLY AFTERNOON...WITH GUSTS IN EXCESS
OF 30 KTS EXPECTED. A BRIEF LULL IN THE WINDS IS EXPECTED AFTER
SUNSET AS A WEAK RIDGE BUILDS OVER THE AREA. MEANWHILE...THE NEXT
CLIPPER SYSTEM WILL BE TAKING AIM AT THE AREA...DROPPING SOUTHEAST
ACROSS NORTHERN IOWA AND MOVING INTO NORTH CENTRAL ILLINOIS AROUND
MIDNIGHT CST TONIGHT. VSBY WILL LIKELY DROP TO IFR WITH VSBY LESS
THAN 1SM A DISTINCT POSSIBILITY. EXPECT TWO TO THREE INCHES OF SNOW
TO ACCUMULATE.
BMD
//ORD AND MDW CONFIDENCE...UPDATED 16Z...
* MEDIUM-HIGH CONFIDENCE IN WIND TRENDS.
* MEDIUM CONFIDENCE IN CIG TRENDS.
* MEDIUM-HIGH CONFIDENCE IN SNOW LATE TONIGHT INTO EARLY WEDNESDAY
WITH IFR VSBY.
BMD/KB
//OUTLOOK FOR ORD/MDW FOR 00Z THURSDAY-12Z TUESDAY...UPDATED 12Z...
WEDNESDAY NIGHT...VFR.
THURSDAY...VFR.
FRIDAY...CHC SNOW...ESPECIALLY LATE. MVFR/IFR PSBL.
SATURDAY...SNOW LIKELY. IFR.
SUNDAY...CHC SNOW. IMPROVING TO VFR.
MONDAY...VFR.
BMD
&&
.MARINE...
324 AM CST
TRANSIENT RIDGE IS MOVING ACROSS THE LAKE EARLY THIS MORNING
ALLOWING WINDS OT BRIEFLY TAPER...AND WILL ALLOW THE FIRST GALE
WARNING TO EXPIRE THIS MORNING FOR THE NORTH HALF OF THE LAKE. THE
RESPITE WILL BE SHORT LIVED HOWEVER AS A CLIPPER SYSTEM WILL MOVE
ACROSS LAKE SUPERIOR THIS AFTERNOON WITH SOUTHWEST WINDS QUICKLY
INCREASING BACK TO GALES ACROSS THE SOUTH HALF OF THE LAKE BY MID
MORNING AHEAD OF THE SYSTEM. WINDS TURN WESTERLY BY MID AFTERNOON
AND THE GALES ARE EXPECTED TO SPREAD TO THE NORTHERN PORTIONS OF
LAKE MICHIGAN. A GALE WARNING REMAINS IN EFFECT FOR THE ENTIRE LAKE
FOR THIS SYSTEM. YET ANOTHER CLIPPER SYSTEM WILL MOVE ACROSS LAKE
MICHIGAN LATE TONIGHT AND EARLY WEDNESDAY. EXPECT WINDS TO TOP OUT
JUST BELOW GALES THOUGH...AROUND 30 KT. WINDS WILL REMAIN BREEZY
THROUGH THE REMAINDER OF THE WEEK AND INTO THE WEEKEND.
BMD
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...WINTER WEATHER ADVISORY...ILZ008-ILZ010-ILZ011-ILZ012-ILZ013-
ILZ014-ILZ019-ILZ020-ILZ021-ILZ022...MIDNIGHT WEDNESDAY TO
10 AM WEDNESDAY.
IN...WINTER WEATHER ADVISORY...INZ001-INZ002...MIDNIGHT WEDNESDAY TO
10 AM WEDNESDAY.
LM...GALE WARNING...LMZ080-LMZ567-LMZ669-LMZ671-LMZ673-LMZ675-LMZ740-
LMZ741-LMZ742-LMZ743-LMZ744-LMZ745-LMZ777-LMZ779-LMZ868-
LMZ870-LMZ872-LMZ874-LMZ876-LMZ878 UNTIL 9 PM TUESDAY.
GALE WARNING...LMZ261-LMZ362-LMZ364-LMZ366-LMZ563-LMZ565...4 PM
TUESDAY TO 3 AM WEDNESDAY.
&&
$$
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
948 AM CST TUE DEC 10 2013
.DISCUSSION...
947 AM CST
FOR MORNING UPDATE...
ONLY MINOR EDITS TO MORNING GRIDS/FORECASTS BASED ON CURRENT
OBSERVATIONAL DATA. HAVE ENDED SNOW SHOWERS AND REPLACED WITH
SCATTERED FLURRIES ACROSS NORTH CENTRAL IL THROUGH LATE MORNING AND
LOWERED HIGH TEMPS A COUPLE OF DEGREES ESPECIALLY SOUTH.
MORNING GOES VAPOR IMAGERY AND RAP INITIALIZATION OF UPPER AIR DATA
DEPICTS MID-LEVEL SHORT WAVE TROUGH MOVING ACROSS THE FORECAST AREA
AT MID-MORNING. AREA OF LIGHT SNOW/SNOW SHOWERS ASSOCIATED WITH THIS
DISTURBANCE WAS MOVING EAST ACROSS THE CWA...MAINLY THE IMMEDIATE
CHICAGO AREA AND ADJACENT NORTHWEST INDIANA/SOUTHERN LAKE MICHIGAN.
A FEW FLURRIES LINGERING BACK ACROSS PARTS OF NORTH CENTRAL IL...
WITH SKIES OTHERWISE BECOMING PARTLY CLOUDY/MOSTLY SUNNY FROM THE
WEST AS THE MID LEVEL WAVE CONTINUES TO TRACK OFF TO THE EAST
THROUGH MID-DAY. AT THE SURFACE...WEAK SURFACE LOW OVER WI PROGGED
TO CONSOLIDATE WITH LOW OVER LAKE SUPERIOR...WITH TRAILING COLD
FRONT ACROSS NORTHERN IA EVENTUALLY TO PUSH ACROSS OUR CWA THIS
AFTERNOON AND GUSTY SOUTHWEST WINDS TO SHIFT WEST. BASED ON SFC OB
TRENDS WITH TEMPS MAINLY IN THE UPPER TEENS UPSTREAM HAVE SHAVED A
COUPLE OF DEGREES OFF OF MAX TEMPS MAINLY ACROSS SOUTHERN CWA.
OTHERWISE...EXCEPT FOR SOME TWEAKS TO SKY COVER GRIDS BASED ON
CURRENT SATELLITE DATA...HAVE MADE NO OTHER CHANGES TO GOING
FORECAST.
RATZER
&&
.PREV DISCUSSION...
329 AM CST
CLICKING MY HEELS THREE TIMES AND CHANTING THERE`S NO PLACE LIKE
CHICAGO IN THE SUMMER HAS YET TO PRODUCE THE DESIRED RESULTS.
FORECAST CHALLENGES THIS MORNING INCLUDE THE POTENTIALLY HIGH IMPACT
LIGHT/MODERATE SNOW LATE TONIGHT/WED MORNING...BITTERLY COLD
TEMPS/WIND CHILLS WED PM INTO WED NIGHT...THEN THE NEXT POTENTIAL
SNOW MAKER FRIDAY NIGHT INTO THE START OF THE WEEKEND.
TEMPS WILL MODERATE PRETTY QUICKLY FROM THE BITTERLY COLD START THIS
MORNING WITH TEMPS REBOUNDING INTO THE TEENS...BUT THE RISE IN TEMPS
WILL BE OFFSET BY THE INCREASINGLY STRONG WINDS WHICH WILL HOLD WIND
CHILLS TO NEAR OR BELOW ZERO MUCH OF THE DAY. WATER VAPOR IMAGERY
SHOWS WELL DEFINED SHORTWAVE DIGGING ESE ACROSS MINNESOTA THIS
MORNING WITH SOME SNOW SHOWERS ASSOCIATED WITH THIS FEATURE ACROSS
MN INT NORTHERN IOWA. TYPICALLY NOT TOO DIFFICULT TO SQUEEZE SNOW
OUT OF AN AIR MASS THIS COLD...SO AS THE SHORTWAVE PIVOTS EAST THIS
MORNING COULD BE SOME SNOW SHOWERS ACROSS MAINLY NORTHERN PORTIONS
OF OUR CWA. THE STRONG WEST WINDS COULD RESULT IN SOME BLOWING AND
DRIFTING SNOW THIS AFTERNOON IN OPEN AREAS.
NEXT SHORTWAVE IN THE HOPPER DIVING SOUTH INTO THE NORTHERN ROCKIES
WILL QUICKLY TRANSLATE EASTWARD TOWARD THE MIDWEST BY LATE TONIGHT
INTO TOMORROW MORNING. STRENGTHENING LOW AND MID LEVEL FRONTOGENESIS
IN ADVANCE OF THIS SHORTWAVE COMBINED WITH BACKING WINDS IN THE
270-285K PRESSURE SURFACE WILL RESULT IN INCREASING LOWER
TROPOSPHERIC ASCENT...WHILE 150KT 300MB JET STREAK IS PROGGED TO
DEVELOP RESULTING IN INCREASING DIVERGENCE ALOFT SETTING THE STAGE
FOR A PRETTY IMPRESSIVE AREA OF SNOW DEVELOPING WITH THIS WAVE.
FAIRLY DEEP DENDRITIC GROWTH ZONE (5000FT+) CO-LOCATED WITH THE
ASCENT COULD ALLOW FOR A PRETTY FLUFFY/HIGH RATIO SNOW. UNLIKE THE
LAST SYSTEM...DEPTH OF THE MOISTURE AND SATURATION IS GREATER AND
EXTENDS WELL ABOVE THE -20C LEVEL...SO SUSPECT THAT THIS SYSTEM WILL
PRODUCE A HIGHER SNL RATIO...LIKELY AT LEAST 15-20:1. GUIDANCE
COMING INTO PRETTY GOOD AGREEMENT ON THE AXIS OF HIGHEST QPF SETTING
UP IN THE I-80 TO I88/290 CORRIDOR WHERE IT`S LOOKING PRETTY LIKELY
THAT A SWATH OF 2 TO LOCALLY 4 INCHES OF SNOW WILL FALL. SNOW LOOKS
TO PEAK IN THE 07-13Z TIME FRAME WESTERN CWA AND 09-15Z OVER CHICAGO
AREA...COINCIDING WITH RUSH HOUR. IN ADDITION TO THE HORRIBLE
TIMING...ANOTHER FACTOR TO MAKE THIS A HIGHER IMPACT EVENT IS THE
COLD AIR TEMPS WHICH WILL RESULT IN UNTREATED SALT BEING LESS
EFFECTIVE ALONG WITH VERY COLD PAVEMENT TEMPS ALSO ADDING TO THE
CHALLENGE FOR ROAD CREWS. WHILE FORECAST SNOWFALL AMOUNTS FALL A
LITTLE SHY OF ADVISORY CRITERIA...THE POTENTIAL FOR THIS TO BE SUCH
A HIGH IMPACT EVENT SEEMS TO JUSTIFY A WINTER WEATHER ADVISORY. PLAN
TO ISSUE IT FOR THE CORRIDOR THAT LOOKS MOST LIKELY TO GET THE
HIGHEST IMPACTS...IT IS POSSIBLE THE DAY SHIFT MAY NEED TO EXPAND
THE AREAL COVERAGE OF THE ADVISORY A BIT...BUT WANTED TO DRAW EARLY
ATTENTION TO THIS POTENTIALLY VERY PROBLEMATIC EVENT.
RE-ENFORCING BLAST OF ARCTIC AIR COMES RUSHING INTO THE AREA
WEDNESDAY AFTERNOON IN THE WAKE OF THE SNOW. TEMPERATURES WILL
LIKELY FALL INTO THE SINGLE DIGITS BY EVENING OVER MOST OF THE AREA
WITH TEMPS POSSIBLY DROPPING BELOW ZERO NORTHWEST CWA BY SUNSET.
STRONG NORTHWEST WINDS WILL RESULT IN WIND CHILLS PLUMMETING WELL
BELOW ZERO...LIKELY 10-20 BELOW BY LATE WEDNESDAY AFTERNOON...THEN
POSSIBLY AS COLD AS 15-30 BELOW ZERO WEDNESDAY NIGHT. LOW TEMPS WILL
BE TRICKY WITH PRESSURE GRADIENT LIKELY TO MAINTAIN SOME WIND
THROUGH THE NIGHT. IN ADDITION...BACKING WINDS LATE AT NIGHT AND
DEVELOPING WARM AIR ADVECTION (MAINLY ALOFT) WITH THE POTENTIAL FOR
CLOUDINESS MOVING IN COULD RESULT IN KEEPING TEMPS FROM GETTING TOO
OUT OF CONTROL. WOULDN`T BE HARD TO ENVISION LATE EVENING LOWS OF
10-15 BELOW IN THE COLDEST LOCATIONS ASSUMING CLOUDS DON`T MAKE AN
EARLY ARRIVAL...BUT THE BUST POTENTIAL WITH LOWS IS HIGH IN BOTH
DIRECTIONS WITH CURRENT FORECAST PROBABLY THE MID RANGE OF THE
POSSIBILITIES. TEMPS SHOULD LEVEL OFF AND POSSIBLY RISE LATE AT
NIGHT AS CLOUDINESS AND WARM AIR ADVECTION INCREASE.
SOME MODERATION IN TEMPS IS EXPECTED THURSDAY WITH CLOUDINESS AND
SOUTHERLY WINDS LIKELY TO RESULT IN NEAR STEADY TEMPS THURSDAY
NIGHT. LOOKS LIKE THINGS COULD GET UNSETTLED WITH ANOTHER CHANCE OF
SNOW FRIDAY NIGHT INTO THE WEEKEND...BUT FORECAST CONFIDENCE IS LOW
AT MEDIUM RANGE MODELS ARE ATTEMPTING TO RESOLVE A VERY COMPLEX
EVOLUTION OF SHORTWAVES. FIRST...A CUT OFF LOW MEANDERING OFF THE
SOUTHERN CALIFORNIA COAST IS PROGGED TO DRIFT EASTWARD INTO THE FOUR
CORNERS REGION BEFORE A NORTHERN STREAM SHORTWAVE DIVES SOUTHEAST
AND CAUSES THE UPPER LOW TO OPEN UP AND BEGIN TO LIFT OUT INTO THE
SOUTHERN PLAINS. BY THE WEEKEND THE MODELS ARE ATTEMPTING TO DEPICT
SOME DEGREE OF PHASING BETWEEN THESE TWO SHORTWAVES WITH A POLAR JET
SHORTWAVE DIGGING SOUTH INTO THE UPPER MISSISSIPPI VALLEY REGION.
MEDIUM RANGE MODELS TEND TO PHASE SHORTWAVES TOO MUCH AND THE RANGE
OF POSSIBILITIES FOR THIS WEEKEND SYSTEM IS STILL VERY LARGE SO IT
IS FAR TOO SOON TO SOUND ANY ALARMS. ANYTIME YOU HAVE A SOUTHWEST
UPPER LOW LIFTING OUT AND POTENTIALLY AFFECTING THE AREA IT IS A
SITUATION THAT REQUIRES MONITORING. ANOTHER LOBE OF ARCTIC AIR IS
CURRENTLY PROGGED TO SPREAD SOUTH INTO THE AREA BEHIND THIS SYSTEM
BUT MODELS DISAGREE ON JUST HOW COLD...SO STAY TUNED.
IZZI
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 14Z...
* BRIEF PERIOD OF -SHSN THIS MORNING BETWEEN 14 AND 16 UTC WITH
VSBY OF 1 TO 2 SM.
* WESTERLY WINDS GUSTING IN EXCESS OF 30 KT LATE THIS MORNING
THROUGH THIS AFTERNOON.
* BETTER CHANCES FOR SNOW LATE TONIGHT INTO EARLY WEDNESDAY WHICH
IS EXPECTED TO PRODUCE 2 TO 3 INCHES OF SNOW ACCUMULATION.
BMD/KB
//DISCUSSION...UPDATED 12Z...
A PAIR OF CLIPPERS WILL RACE ACROSS THE AREA IN THE UPCOMING TAF
PERIOD. THE FIRST SYSTEM IS ALREADY PUSHING EAST ACROSS WISCONSIN
WITH A FEW PATCHES OF SNOW DEVELOPING AS FAR SOUTH AS EASTERN IOWA
EARLY THIS MORNING. THIS AREA OF SNOW WILL BE THE MAIN CONCERN THIS
MORNING AS IT WILL TRACK NEAR THE TERMINALS. HAVE INCLUDED TEMPO FOR
SNOW AT RFD...BUT NAM/RAP GUIDANCE WHICH SEEM TO BE INITIALIZING
BEST ON THIS AREA OF SNOW BOTH SUGGEST IT WILL LIFT NORTH OF THE
CHICAGO AREA TERMINALS WHILE DISSIPATING LATER THIS MORNING. IF ON
THE OFF CHANCE IT WERE TO IMPACT THE TERMINALS...WOULD EXPECT VSBY
TO DROP ANYWHERE FROM 1/2SM TO 2SM FOR ABOUT AN HOUR. WINDS WILL BE
VEERING BACK TO THE WEST BY EARLY AFTERNOON...WITH GUSTS IN EXCESS
OF 30 KTS EXPECTED. A BRIEF LULL IN THE WINDS IS EXPECTED AFTER
SUNSET AS A WEAK RIDGE BUILDS OVER THE AREA. MEANWHILE...THE NEXT
CLIPPER SYSTEM WILL BE TAKING AIM AT THE AREA...DROPPING SOUTHEAST
ACROSS NORTHERN IOWA AND MOVING INTO NORTH CENTRAL ILLINOIS AROUND
MIDNIGHT CST TONIGHT. VSBY WILL LIKELY DROP TO IFR WITH VSBY LESS
THAN 1SM A DISTINCT POSSIBILITY. EXPECT TWO TO THREE INCHES OF SNOW
TO ACCUMULATE.
BMD
//ORD AND MDW CONFIDENCE...UPDATED 14Z...
* HIGH CONFIDENCE IN SNOW IMPACTING TERMINALS THIS MORNING WITH 1
TO 2 SM VIS FOR A SHORT PERIOD THROUGH 16 UTC.
* MEDIUM-HIGH CONFIDENCE IN WIND TRENDS.
* MEDIUM CONFIDENCE IN CIG TRENDS.
* MEDIUM-HIGH CONFIDENCE IN SNOW LATE TONIGHT INTO EARLY WEDNESDAY
WITH IFR VSBY.
BMD/KB
//OUTLOOK FOR ORD/MDW FOR 00Z THURSDAY-12Z TUESDAY...UPDATED 12Z...
WEDNESDAY NIGHT...VFR.
THURSDAY...VFR.
FRIDAY...CHC SNOW...ESPECIALLY LATE. MVFR/IFR PSBL.
SATURDAY...SNOW LIKELY. IFR.
SUNDAY...CHC SNOW. IMPROVING TO VFR.
MONDAY...VFR.
BMD
&&
.MARINE...
324 AM CST
TRANSIENT RIDGE IS MOVING ACROSS THE LAKE EARLY THIS MORNING
ALLOWING WINDS OT BRIEFLY TAPER...AND WILL ALLOW THE FIRST GALE
WARNING TO EXPIRE THIS MORNING FOR THE NORTH HALF OF THE LAKE. THE
RESPITE WILL BE SHORT LIVED HOWEVER AS A CLIPPER SYSTEM WILL MOVE
ACROSS LAKE SUPERIOR THIS AFTERNOON WITH SOUTHWEST WINDS QUICKLY
INCREASING BACK TO GALES ACROSS THE SOUTH HALF OF THE LAKE BY MID
MORNING AHEAD OF THE SYSTEM. WINDS TURN WESTERLY BY MID AFTERNOON
AND THE GALES ARE EXPECTED TO SPREAD TO THE NORTHERN PORTIONS OF
LAKE MICHIGAN. A GALE WARNING REMAINS IN EFFECT FOR THE ENTIRE LAKE
FOR THIS SYSTEM. YET ANOTHER CLIPPER SYSTEM WILL MOVE ACROSS LAKE
MICHIGAN LATE TONIGHT AND EARLY WEDNESDAY. EXPECT WINDS TO TOP OUT
JUST BELOW GALES THOUGH...AROUND 30 KT. WINDS WILL REMAIN BREEZY
THROUGH THE REMAINDER OF THE WEEK AND INTO THE WEEKEND.
BMD
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...WINTER WEATHER ADVISORY...ILZ008-ILZ010-ILZ011-ILZ012-ILZ013-
ILZ014-ILZ019-ILZ020-ILZ021-ILZ022...MIDNIGHT WEDNESDAY TO
10 AM WEDNESDAY.
IN...WINTER WEATHER ADVISORY...INZ001-INZ002...MIDNIGHT WEDNESDAY TO
10 AM WEDNESDAY.
LM...GALE WARNING...LMZ080-LMZ567-LMZ669-LMZ671-LMZ673-LMZ675-LMZ740-
LMZ741-LMZ742-LMZ743-LMZ744-LMZ745-LMZ777-LMZ779-LMZ868-
LMZ870-LMZ872-LMZ874-LMZ876-LMZ878 UNTIL 9 PM TUESDAY.
GALE WARNING...LMZ261-LMZ362-LMZ364-LMZ366-LMZ563-LMZ565...4 PM
TUESDAY TO 3 AM WEDNESDAY.
&&
$$
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
326 AM CST TUE DEC 10 2013
.DISCUSSION...
718 PM CST
ONLY ISSUES THUS FAR HAVE BEEN TEMPERATURES TAKING A NOSE DIVE.
RFD DROPPED TO 3 DEGREES ALREADY WITH OTHER STATIONS UNDER CLEAR
SKIES TANKING AS WELL. AS LOWERED LOW TEMPS FOR TONIGHT WITH
OUTLYING AREAS DIPPING JUST BELOW ZERO. BASED ON TRENDS...TEMPS
MAY FALL A BIT LOWER THAN CURRENTLY FORECAST FOR AREAS NORTH OF A
LASALLE TO OHARE AIRPORT LINE. BASICALLY WHERE THE SKY IS CLEAR.
USED HRRR TRENDS WITH A FEW HAND EDITS TO GET TEMP TREND TONIGHT
SINCE AREAS UNDER THE CLOUD COVER WILL COOL VERY SLOWLY.
ISSUED A SPS TO HIGHLIGHT THE COLD TEMPS AND WIND CHILLS SINCE
THIS IS THE COLDEST WE HAVE BEEN THIS SEASON. MIN WIND CHILLS
OF -10 TO -15 ARE EXPECTED FOR AREAS IN AND NORTH OF A LASALLE
COUNTY TO WILL COUNTY LINE. ISOLATED AREAS NORTH OF I-90 MAY EVEN
SEEN MIN WIND CHILLS APPROACHING -20. HOWEVER THE AREA OF -20 WILL
NOT BE WIDESPREAD ENOUGH TO WARRANT A WIND CHILL ADVISORY.
OTHERWISE MADE MINOR ADJUSTMENTS TO SKY COVER AS THE
REST OF THE FORECAST IS ON TRACK. STILL EXPECTING TEMPS TO RISE A
BIT AROUND SUNRISE AS CLOUD COVER ASSOCIATED WITH THE NEXT CLIPPER
MOVE IN.
JEE
//PREV DISCUSSION...
253 PM CST
IT APPEARS WE ARE STUCK IN MOTHER NATURES WINTER PATTERN...AND FOR
THE NEXT SEVERAL DAYS IT DOES NOT APPEAR WE ARE LOOKING AT A BREAK
FROM THIS SETUP. LONG-TERM PATTERN IS BEGINNING TO SHOW JUST A BRIEF
RESPITE...THEN A RETURN TO UNSEASONABLY COLD SETUP.
IT`S THE GIFT THAT KEEPS ON GIVING CLARK.
THIS AFTERNOON/EVENING...WILL REMAIN RELATIVELY QUIET FOR THE
FORECAST AREA...HOWEVER THAT WILL CHANGE TOWARDS DAYBREAK TUESDAY.
SFC RIDGE HAS BECOME CENTERED ACROSS THE MID-MISSOURI
VALLEY...BEGINNING TO STRETCH EAST THROUGH THE OHIO VALLEY. THE
DEPARTING SFC LOW THAT BROUGHT THE FRESH BLANKET OF SNOW HAS LIFTED
NORTHEAST OF LAKE HURON...MEANWHILE A CLIPPER IS BEGINNING TO DIP
INTO THE NORTHERN PLAINS LATE THIS AFTERNOON. IR IMAGERY SHOWS A
CHANNEL OF CLOUDS OVER SAINT LOUIS STRETCHING NORTHEAST THROUGH
SOUTHERN LAKE MICHIGAN...ASSOCIATED WITH A FRONTAL BOUNDARY THAT
CONTINUES TO SLOWLY SLIDE EAST/SOUTHEAST ACROSS THE FORECAST AREA.
TEMPS AHEAD OF THIS BOUNDARY HAVE HELD STEADY IN THE LOW 20S...WHILE
BEHIND THIS BOUNDARY TEMPS HAVE ALREADY FALLEN INTO THE MID/UPR
TEENS. ACROSS THE STATELINE INTO IOWA...TEMPS HAVE HELD IN THE
SINGLE DIGITS ABOVE ZERO.
GUIDANCE HAS TRENDED SLIGHTLY FURTHER SOUTH WITH THE FIRST CLIPPER
TONIGHT...AND AS A RESULT HAVE INCREASED POPS ACROSS THE NORTHERN
CWFA. THE PRESSURE GRADIENT DOES INCREASE THIS EVENING...AND WILL
PERSIST THRU DAYBREAK TUE. THIS WILL LIKELY RESULT IN SOME BLOWING
SNOW. AS NOTED ABOUT INCREASED POPS...THIS HAS RESULTED IN LIGHT
SNOW EXPECTED JUST BEFORE DAYBREAK TUE FOR THE NORTHERN HALF OF THE
CWFA.
USING THE COBB TECHNIQUE WOULD SUGGEST A FEW POINTS BETWEEN 09-12Z
COULD PICK-UP A COUPLE TENTHS OF AN INCH OF SNOWFALL. WITH THE
BREEZY CONDS EXPECTED...AND COLD AIR IN PLACE...TEMPS WILL LIKELY
TUMBLE TO THE SINGLE DIGITS ABOVE ZERO AND WIND CHILL VALUES WELL
BELOW ZERO AND NEARING -15 IN A FEW LOCATIONS WEST OF THE FOX
VALLEY.
CONFIDENCE...HIGH.
TUESDAY THROUGH WEDNESDAY...
500MB TROUGH AXIS HAS TRENDED STRONGER...WHICH HAS ALSO DISPLACED
THE CLIPPER POISED TO ARRIVE ACROSS THE REGION FURTHER SOUTH TUE
MORNING. AS A RESULT HAVE INTRODUCED POPS TO ACCOMMODATE THIS THRU
18Z TUE. BUT IN TRADITIONAL FASHION...THIS CLIPPER SHUD QUICKLY PUSH
EAST BY EARLY AFTN WITH WEAK SFC RIDGING PUSHING BACK INTO THE
FORECAST AREA. SOME WEAK WARMING MAY OCCUR WITH THIS SYSTEM
EARLY...ALLOWING TEMPS TO WARM INTO THE TEENS TO PSBLY LOW 20S ALONG
THE SOUTHERN CWFA TUE AFTN.
THEN YET ANOTHER CLIPPER IS PROGGED TO TRAVERSE THE REGION LATE TUE
NGT/WED...WHICH HAS CONTINUED TO TREND FURTHER SOUTH AND STRONGER.
WITH THE SFC RIDGE DRIFTING SOUTH INTO THE TENN VALLEY...THIS WILL
LIKELY ALLOW THE WAVE TO PUSH ACROSS THE HEART OF THE CWFA. QPF OF
ARND 0.10" FOR THIS SECOND CLIPPER SNOW RATIOS WILL HOVER ARND 15:1
TO 20:1. THE BEST OMEGA/LIFT IS PUSHING INTO THE FAVORED DGZ WED
MORNING...WHICH COULD HELP PRODUCE LARGER DENDRITES AND INCREASE
SNOWFALL ACCUM RATES. AT THIS POINT HAVE ACCUMS GENERALLY BETWEEN
1-3"...AND COULD SEE A FEW LOCATIONS BETWEEN THE I-80 AND I-88
CORRIDOR COULD PICK UP CLOSE TO 4" BY LATE WED MORNING.
THEN HIGH PRESSURE BUILDS BACK INTO THE REGION WED NGT...SETTING THE
STAGE FOR A VERY COLD NIGHT INTO THUR MORNING. THE RIDGE CENTER HAS
ALSO TRENDED SLIGHTLY FURTHER SOUTH...WHICH WILL LIKELY KEEP SOME
WEST/NORTHWEST WIND COMPONENT. DESPITE THIS TEMPS SHUD STILL RADIATE
INTO THE SINGLE DIGITS BELOW ZERO.
CONFIDENCE...HIGH.
CONFIDENCE IN ACCUMULATING SNOWFALL WED...HIGH.
THURSDAY THROUGH SUNDAY...
PREVIOUS GUIDANCE HAD HELD THE SFC RIDGE OVER THE FORECAST AREA THUR
MORNING...WITH DRY WEATHER. HOWEVER AS HAS BEEN THE CASE WITH THE
PRIOR COUPLE OF CLIPPERS...AND PLACEMENT OF THE 500MB TROUGH
AXIS...GUIDANCE HAS NOW INTRODUCED YET ANOTHER CLIPPER SLICING
SOUTHEAST ACROSS THE NORTHERN PLAINS EARLY THUR...AND COULD BRING A
PERIOD OF LIGHT SNOW/FLURRIES INTO NORTHERN IL THUR MORNING. THIS
MAY RESULT IN TEMPS THUR MORNING NOT GETTING AS COLD...BUT THAT WILL
HINGE UPON TIMING AND CLOUD COVER FROM THE AFOREMENTIONED CLIPPER.
THEN A RELATIVELY QUIET PERIOD FOR FRI WITH THE 500MB FLOW TRYING TO
FLATTEN...BUT THIS WILL ONLY BE BRIEF. GUIDANCE IS NOW BEGINNING TO
TREND TOWARDS AN INVERTED TROUGH DEVELOPING IN THE WAKE OF THE SFC
RIDGE FRI...WITH A STRONG SHORTWAVE TAKING SHAPE ACROSS THE SOUTHERN
PLAINS FRIDAY EVENING. THIS SYSTEM WILL NEED TO BE CLOSELY MONITORED
FOR THE UPCOMING WEEKEND...AS THIS COULD SPREAD ACCUMULATING
SNOWFALL THROUGH THE OHIO VALLEY INTO NORTHERN IL/NORTHWEST IN.
THE LATEST GFS INDICATES AN 850MB LOW ASSOCIATED WITH THIS INVERTED
TROUGH...LIFTING NORTHEAST ACROSS CENTRAL IL THEN NORTHEAST INTO
NORTHCENTRAL IN MIDDAY SAT. LLVL FLOW AHEAD OF THIS FEATURE WILL BE
TURNING NORTHEAST SAT...SETTING UP THE POTENTIAL FOR A HYBRID SYSTEM
OF LAKE EFFECT SNOW AND POTENTIALLY SYNOPTIC SNOW SAT.
TEMPS SHUD BEGIN TO WARM TO NEAR 30 DEG...OR POSSIBLY THE FREEZING
POINT FRI THRU SAT. THEN WITH YET ANOTHER ARCTIC AIRMASS POISED TO
PUSH BEHIND THIS SYSTEM SUN.
CONFIDENCE...HIGH.
BEACHLER
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 09Z...
* STRONG WESTERLY WINDS DURING THE DAY TUESDAY...WITH GUSTS IN
EXCESS OF 30 KT.
* POTENTIAL FOR LIGHT FLURRIES OR A FEW SNOW SHOWERS LATE
MORNING/EARLY AFTERNOON.
* MORE SIGNIFICANT SNOW POTENTIAL LATE TUESDAY NIGHT.
BMD
//DISCUSSION...UPDATED 06Z...
TRANSIENT SURFACE RIDGE IS PUSHING ACROSS THE AREAS THIS EVENING
ALLOWING WINDS TO BRIEFLY BACK TO THE SSW/SW AND WEAKEN. WINDS WILL
VEER TO THE WSW AGAIN TOMORROW AFTER DAYBREAK AS A CLIPPER SYSTEM
SKIRTS JUST NORTH OF THE AREA. A TIGHT GRADIENT AND STRONG CHANGES
IN THE SURFACE PRESSURE WILL RESULT IN A SHARP INCREASE IN WINDS.
WINDS AT THE TOP OF THE MIXED LAYER ARE AROUND 35 KTS AND WOULD
EXPECT TO TAP INTO THESE STRONGER WINDS BY EARLY AFTERNOON. MAIN
FORCING ASSOCIATED WITH THE UPPER WAVE WILL BE FOCUSED OVER
WISCONSIN...THOUGH SOME LIFT IS NOTED SOUTH INTO NORTHERN ILLINOIS
WHERE THE MOISTURE IS SHALLOW. DESPITE THE MEAGER MOISTURE...A FEW
FLURRIES ARE POSSIBLE THOUGH WOULD NOT ANTICIPATE ANY IMPACTS TO
VSBY NOR ANY ACCUMULATION. WINDS WILL SETTLE AROUND SUNSET AS
ANOTHER RIDGE TRANSLATES EAST ACROSS THE AREA...BUT YET ANOTHER
CLIPPER SYSTEM WILL BE RIGHT ON ITS HEELS. THIS NEXT SYSTEM LOOKS TO
TRACK RIGHT OVER NORTHERN ILLINOIS LATE TUESDAY NIGHT INTO EARLY
WEDNESDAY...PIVOTING ACROSS THE TERMINALS WHICH COULD RESULT IN A
FEW INCHES OF SNOW ACCUMULATION AND LIKELY PERIODS OF IFR VSBY.
BMD
//ORD AND MDW CONFIDENCE...UPDATED 09Z...
* MEDIUM-HIGH CONFIDENCE IN WIND SPEEDS/DIRECTION.
* LOW CONFIDENCE IN SNOW IMPACTING TERMINALS MIDDAY
TUESDAY...THOUGH THERE IS AN AREA OF -SN EXPANDING OVER CENTRAL
IOWA THAT WILL HAVE TO MONITOR.
* MEDIUM-HIGH CONFIDENCE IN ACCUMULATING SNOW LATE TUESDAY NIGHT
INTO EARLY WEDNESDAY.
BMD
//OUTLOOK FOR ORD/MDW FOR 12Z WEDNESDAY-12Z MONDAY...UPDATED 00Z...
WEDNESDAY...SNOW ENDING TOWARD MIDDAY. BECOMING VFR.
THURSDAY...VFR.
FRIDAY...VFR WITH SNOW CHANCES INCREASING FRIDAY EVENING. IFR
DEVELOPING FRIDAY EVENING.
SATURDAY...CHANCE FOR SNOW. IFR/MVFR.
SUNDAY...IMPROVING TO VFR.
MDB
&&
.MARINE...
324 AM CST
TRANSIENT RIDGE IS MOVING ACROSS THE LAKE EARLY THIS MORNING
ALLOWING WINDS OT BRIEFLY TAPER...AND WILL ALLOW THE FIRST GALE
WARNING TO EXPIRE THIS MORNING FOR THE NORTH HALF OF THE LAKE. THE
RESPITE WILL BE SHORT LIVED HOWEVER AS A CLIPPER SYSTEM WILL MOVE
ACROSS LAKE SUPERIOR THIS AFTERNOON WITH SOUTHWEST WINDS QUICKLY
INCREASING BACK TO GALES ACROSS THE SOUTH HALF OF THE LAKE BY MID
MORNING AHEAD OF THE SYSTEM. WINDS TURN WESTERLY BY MID AFTERNOON
AND THE GALES ARE EXPECTED TO SPREAD TO THE NORTHERN PORTIONS OF
LAKE MICHIGAN. A GALE WARNING REMAINS IN EFFECT FOR THE ENTIRE LAKE
FOR THIS SYSTEM. YET ANOTHER CLIPPER SYSTEM WILL MOVE ACROSS LAKE
MICHIGAN LATE TONIGHT AND EARLY WEDNESDAY. EXPECT WINDS TO TOP OUT
JUST BELOW GALES THOUGH...AROUND 30 KT. WINDS WILL REMAIN BREEZY
THROUGH THE REMAINDER OF THE WEEK AND INTO THE WEEKEND.
BMD
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...WINTER WEATHER ADVISORY...ILZ008-ILZ010-ILZ011-ILZ012-ILZ013-
ILZ014-ILZ019-ILZ020-ILZ021-ILZ022...MIDNIGHT WEDNESDAY TO
10 AM WEDNESDAY.
IN...WINTER WEATHER ADVISORY...INZ001-INZ002...MIDNIGHT WEDNESDAY TO
10 AM WEDNESDAY.
LM...GALE WARNING...LMZ080-LMZ567-LMZ669-LMZ671-LMZ673-LMZ675-LMZ740-
LMZ741-LMZ742-LMZ743-LMZ744-LMZ745-LMZ777-LMZ779-LMZ868-
LMZ870-LMZ872-LMZ874-LMZ876-LMZ878...8 AM TUESDAY TO 9 PM
TUESDAY.
GALE WARNING...LMZ261-LMZ362-LMZ364-LMZ366-LMZ563-LMZ565...4 PM
TUESDAY TO 3 AM WEDNESDAY.
SMALL CRAFT ADVISORY...NEARSHORE GARY TO MICHIGAN CITY IN UNTIL 8 AM TUESDAY.
&&
$$
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
1150 PM CST MON DEC 9 2013
.DISCUSSION...
718 PM CST
ONLY ISSUES THUS FAR HAVE BEEN TEMPERATURES TAKING A NOSE DIVE.
RFD DROPPED TO 3 DEGREES ALREADY WITH OTHER STATIONS UNDER CLEAR
SKIES TANKING AS WELL. AS LOWERED LOW TEMPS FOR TONIGHT WITH
OUTLYING AREAS DIPPING JUST BELOW ZERO. BASED ON TRENDS...TEMPS
MAY FALL A BIT LOWER THAN CURRENTLY FORECAST FOR AREAS NORTH OF A
LASALLE TO OHARE AIRPORT LINE. BASICALLY WHERE THE SKY IS CLEAR.
USED HRRR TRENDS WITH A FEW HAND EDITS TO GET TEMP TREND TONIGHT
SINCE AREAS UNDER THE CLOUD COVER WILL COOL VERY SLOWLY.
ISSUED A SPS TO HIGHLIGHT THE COLD TEMPS AND WIND CHILLS SINCE
THIS IS THE COLDEST WE HAVE BEEN THIS SEASON. MIN WIND CHILLS
OF -10 TO -15 ARE EXPECTED FOR AREAS IN AND NORTH OF A LASALLE
COUNTY TO WILL COUNTY LINE. ISOLATED AREAS NORTH OF I-90 MAY EVEN
SEEN MIN WIND CHILLS APPROACHING -20. HOWEVER THE AREA OF -20 WILL
NOT BE WIDESPREAD ENOUGH TO WARRANT A WIND CHILL ADVISORY.
OTHERWISE MADE MINOR ADJUSTMENTS TO SKY COVER AS THE
REST OF THE FORECAST IS ON TRACK. STILL EXPECTING TEMPS TO RISE A
BIT AROUND SUNRISE AS CLOUD COVER ASSOCIATED WITH THE NEXT CLIPPER
MOVE IN.
JEE
//PREV DISCUSSION...
253 PM CST
IT APPEARS WE ARE STUCK IN MOTHER NATURES WINTER PATTERN...AND FOR
THE NEXT SEVERAL DAYS IT DOES NOT APPEAR WE ARE LOOKING AT A BREAK
FROM THIS SETUP. LONG-TERM PATTERN IS BEGINNING TO SHOW JUST A BRIEF
RESPITE...THEN A RETURN TO UNSEASONABLY COLD SETUP.
IT`S THE GIFT THAT KEEPS ON GIVING CLARK.
THIS AFTERNOON/EVENING...WILL REMAIN RELATIVELY QUIET FOR THE
FORECAST AREA...HOWEVER THAT WILL CHANGE TOWARDS DAYBREAK TUESDAY.
SFC RIDGE HAS BECOME CENTERED ACROSS THE MID-MISSOURI
VALLEY...BEGINNING TO STRETCH EAST THROUGH THE OHIO VALLEY. THE
DEPARTING SFC LOW THAT BROUGHT THE FRESH BLANKET OF SNOW HAS LIFTED
NORTHEAST OF LAKE HURON...MEANWHILE A CLIPPER IS BEGINNING TO DIP
INTO THE NORTHERN PLAINS LATE THIS AFTERNOON. IR IMAGERY SHOWS A
CHANNEL OF CLOUDS OVER SAINT LOUIS STRETCHING NORTHEAST THROUGH
SOUTHERN LAKE MICHIGAN...ASSOCIATED WITH A FRONTAL BOUNDARY THAT
CONTINUES TO SLOWLY SLIDE EAST/SOUTHEAST ACROSS THE FORECAST AREA.
TEMPS AHEAD OF THIS BOUNDARY HAVE HELD STEADY IN THE LOW 20S...WHILE
BEHIND THIS BOUNDARY TEMPS HAVE ALREADY FALLEN INTO THE MID/UPR
TEENS. ACROSS THE STATELINE INTO IOWA...TEMPS HAVE HELD IN THE
SINGLE DIGITS ABOVE ZERO.
GUIDANCE HAS TRENDED SLIGHTLY FURTHER SOUTH WITH THE FIRST CLIPPER
TONIGHT...AND AS A RESULT HAVE INCREASED POPS ACROSS THE NORTHERN
CWFA. THE PRESSURE GRADIENT DOES INCREASE THIS EVENING...AND WILL
PERSIST THRU DAYBREAK TUE. THIS WILL LIKELY RESULT IN SOME BLOWING
SNOW. AS NOTED ABOUT INCREASED POPS...THIS HAS RESULTED IN LIGHT
SNOW EXPECTED JUST BEFORE DAYBREAK TUE FOR THE NORTHERN HALF OF THE
CWFA.
USING THE COBB TECHNIQUE WOULD SUGGEST A FEW POINTS BETWEEN 09-12Z
COULD PICK-UP A COUPLE TENTHS OF AN INCH OF SNOWFALL. WITH THE
BREEZY CONDS EXPECTED...AND COLD AIR IN PLACE...TEMPS WILL LIKELY
TUMBLE TO THE SINGLE DIGITS ABOVE ZERO AND WIND CHILL VALUES WELL
BELOW ZERO AND NEARING -15 IN A FEW LOCATIONS WEST OF THE FOX
VALLEY.
CONFIDENCE...HIGH.
TUESDAY THROUGH WEDNESDAY...
500MB TROUGH AXIS HAS TRENDED STRONGER...WHICH HAS ALSO DISPLACED
THE CLIPPER POISED TO ARRIVE ACROSS THE REGION FURTHER SOUTH TUE
MORNING. AS A RESULT HAVE INTRODUCED POPS TO ACCOMMODATE THIS THRU
18Z TUE. BUT IN TRADITIONAL FASHION...THIS CLIPPER SHUD QUICKLY PUSH
EAST BY EARLY AFTN WITH WEAK SFC RIDGING PUSHING BACK INTO THE
FORECAST AREA. SOME WEAK WARMING MAY OCCUR WITH THIS SYSTEM
EARLY...ALLOWING TEMPS TO WARM INTO THE TEENS TO PSBLY LOW 20S ALONG
THE SOUTHERN CWFA TUE AFTN.
THEN YET ANOTHER CLIPPER IS PROGGED TO TRAVERSE THE REGION LATE TUE
NGT/WED...WHICH HAS CONTINUED TO TREND FURTHER SOUTH AND STRONGER.
WITH THE SFC RIDGE DRIFTING SOUTH INTO THE TENN VALLEY...THIS WILL
LIKELY ALLOW THE WAVE TO PUSH ACROSS THE HEART OF THE CWFA. QPF OF
ARND 0.10" FOR THIS SECOND CLIPPER SNOW RATIOS WILL HOVER ARND 15:1
TO 20:1. THE BEST OMEGA/LIFT IS PUSHING INTO THE FAVORED DGZ WED
MORNING...WHICH COULD HELP PRODUCE LARGER DENDRITES AND INCREASE
SNOWFALL ACCUM RATES. AT THIS POINT HAVE ACCUMS GENERALLY BETWEEN
1-3"...AND COULD SEE A FEW LOCATIONS BETWEEN THE I-80 AND I-88
CORRIDOR COULD PICK UP CLOSE TO 4" BY LATE WED MORNING.
THEN HIGH PRESSURE BUILDS BACK INTO THE REGION WED NGT...SETTING THE
STAGE FOR A VERY COLD NIGHT INTO THUR MORNING. THE RIDGE CENTER HAS
ALSO TRENDED SLIGHTLY FURTHER SOUTH...WHICH WILL LIKELY KEEP SOME
WEST/NORTHWEST WIND COMPONENT. DESPITE THIS TEMPS SHUD STILL RADIATE
INTO THE SINGLE DIGITS BELOW ZERO.
CONFIDENCE...HIGH.
CONFIDENCE IN ACCUMULATING SNOWFALL WED...HIGH.
THURSDAY THROUGH SUNDAY...
PREVIOUS GUIDANCE HAD HELD THE SFC RIDGE OVER THE FORECAST AREA THUR
MORNING...WITH DRY WEATHER. HOWEVER AS HAS BEEN THE CASE WITH THE
PRIOR COUPLE OF CLIPPERS...AND PLACEMENT OF THE 500MB TROUGH
AXIS...GUIDANCE HAS NOW INTRODUCED YET ANOTHER CLIPPER SLICING
SOUTHEAST ACROSS THE NORTHERN PLAINS EARLY THUR...AND COULD BRING A
PERIOD OF LIGHT SNOW/FLURRIES INTO NORTHERN IL THUR MORNING. THIS
MAY RESULT IN TEMPS THUR MORNING NOT GETTING AS COLD...BUT THAT WILL
HINGE UPON TIMING AND CLOUD COVER FROM THE AFOREMENTIONED CLIPPER.
THEN A RELATIVELY QUIET PERIOD FOR FRI WITH THE 500MB FLOW TRYING TO
FLATTEN...BUT THIS WILL ONLY BE BRIEF. GUIDANCE IS NOW BEGINNING TO
TREND TOWARDS AN INVERTED TROUGH DEVELOPING IN THE WAKE OF THE SFC
RIDGE FRI...WITH A STRONG SHORTWAVE TAKING SHAPE ACROSS THE SOUTHERN
PLAINS FRIDAY EVENING. THIS SYSTEM WILL NEED TO BE CLOSELY MONITORED
FOR THE UPCOMING WEEKEND...AS THIS COULD SPREAD ACCUMULATING
SNOWFALL THROUGH THE OHIO VALLEY INTO NORTHERN IL/NORTHWEST IN.
THE LATEST GFS INDICATES AN 850MB LOW ASSOCIATED WITH THIS INVERTED
TROUGH...LIFTING NORTHEAST ACROSS CENTRAL IL THEN NORTHEAST INTO
NORTHCENTRAL IN MIDDAY SAT. LLVL FLOW AHEAD OF THIS FEATURE WILL BE
TURNING NORTHEAST SAT...SETTING UP THE POTENTIAL FOR A HYBRID SYSTEM
OF LAKE EFFECT SNOW AND POTENTIALLY SYNOPTIC SNOW SAT.
TEMPS SHUD BEGIN TO WARM TO NEAR 30 DEG...OR POSSIBLY THE FREEZING
POINT FRI THRU SAT. THEN WITH YET ANOTHER ARCTIC AIRMASS POISED TO
PUSH BEHIND THIS SYSTEM SUN.
CONFIDENCE...HIGH.
BEACHLER
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 06Z...
* STRONG WESTERLY WINDS DURING THE DAY TUESDAY...WITH GUSTS IN
EXCESS OF 30 KT.
* LOW POTENTIAL FOR LIGHT FLURRIES OR A FEW SNOW SHOWERS.
* MORE SIGNIFICANT SNOW POTENTIAL LATE TUESDAY NIGHT.
BMD
//DISCUSSION...UPDATED 06Z...
TRANSIENT SURFACE RIDGE IS PUSHING ACROSS THE AREAS THIS EVENING
ALLOWING WINDS TO BRIEFLY BACK TO THE SSW/SW AND WEAKEN. WINDS WILL
VEER TO THE WSW AGAIN TOMORROW AFTER DAYBREAK AS A CLIPPER SYSTEM
SKIRTS JUST NORTH OF THE AREA. A TIGHT GRADIENT AND STRONG CHANGES
IN THE SURFACE PRESSURE WILL RESULT IN A SHARP INCREASE IN WINDS.
WINDS AT THE TOP OF THE MIXED LAYER ARE AROUND 35 KTS AND WOULD
EXPECT TO TAP INTO THESE STRONGER WINDS BY EARLY AFTERNOON. MAIN
FORCING ASSOCIATED WITH THE UPPER WAVE WILL BE FOCUSED OVER
WISCONSIN...THOUGH SOME LIFT IS NOTED SOUTH INTO NORTHERN ILLINOIS
WHERE THE MOISTURE IS SHALLOW. DESPITE THE MEAGER MOISTURE...A FEW
FLURRIES ARE POSSIBLE THOUGH WOULD NOT ANTICIPATE ANY IMPACTS TO
VSBY NOR ANY ACCUMULATION. WINDS WILL SETTLE AROUND SUNSET AS
ANOTHER RIDGE TRANSLATES EAST ACROSS THE AREA...BUT YET ANOTHER
CLIPPER SYSTEM WILL BE RIGHT ON ITS HEELS. THIS NEXT SYSTEM LOOKS TO
TRACK RIGHT OVER NORTHERN ILLINOIS LATE TUESDAY NIGHT INTO EARLY
WEDNESDAY...PIVOTING ACROSS THE TERMINALS WHICH COULD RESULT IN A
FEW INCHES OF SNOW ACCUMULATION AND LIKELY PERIODS OF IFR VSBY.
BMD
//ORD AND MDW CONFIDENCE...UPDATED 06Z...
* MEDIUM-HIGH CONFIDENCE IN WIND SPEEDS/DIRECTION.
* LOW CONFIDENCE IN SNOW IMPACTING TERMINALS MIDDAY TUESDAY...BUT
MEDIUM-HIGH CONFIDENCE IF THERE IS ANY IT WOULD ONLY BE LIGHT
FLURRIES WITH NO SIG IMPACTS TO VSBY.
* MEDIUM-HIGH CONFIDENCE IN ACCUMULATING SNOW LATE TUESDAY NIGHT
INTO EARLY WEDNESDAY.
BMD
//OUTLOOK FOR ORD/MDW FOR 12Z WEDNESDAY-12Z MONDAY...UPDATED 00Z...
WEDNESDAY...SNOW ENDING TOWARD MIDDAY. BECOMING VFR.
THURSDAY...VFR.
FRIDAY...VFR WITH SNOW CHANCES INCREASING FRIDAY EVENING. IFR
DEVELOPING FRIDAY EVENING.
SATURDAY...CHANCE FOR SNOW. IFR/MVFR.
SUNDAY...IMPROVING TO VFR.
MDB
&&
.MARINE...
145 PM CST
MAIN MARINE FORECAST CONCERNS ARE A COUPLE OF PERIODS OF GALE FORCE
WINDS OVER NORTHERN LAKE MICHIGAN THIS AFTERNOON/EVENING...AND AGAIN
TUESDAY AND TUESDAY NIGHT ACROSS THE ENTIRE LAKE. HAVE UPGRADED GALE
WATCH TO A GALE WARNING FOR TUESDAY AND TUESDAY NIGHT.
STRENGTHENING LOW PRESSURE WAS LOCATED JUST NORTH AND NORTHEAST OF
LAKE SUPERIOR THIS AFTERNOON...AND WILL CONTINUE TO DEEPEN AS IT
LIFTS TOWARD JAMES BAY THIS EVENING. AS THE LOW DEEPENS...A PERIOD
OF TIGHTENING SURFACE PRESSURE GRADIENT WAS RESULTING IN LOW-END
WEST GALES ACROSS MAINLY NORTHERN LAKE MICHIGAN WITH GRAND TRAVERSE
LIGHT GUSTING 34 KTS AS OF NOON CST. GALES WILL LINGER TONIGHT AS
THE LOW PULLS AWAY...GRADUALLY EASING AFTER MIDNIGHT ACROSS THE FAR
NORTHERN PORTION OF THE LAKE AS WEAK HIGH PRESSURE RIDGING MOVES
ACROSS THE WESTERN LAKES. THE LULL LOOKS TO BE BRIEF HOWEVER...AS A
FAST MOVING CLIPPER SYSTEM CURRENTLY MOVING ACROSS FAR SOUTHERN
SASKATCHEWAN TRAVELS QUICKLY TO THE UPPER MISSISSIPPI VALLEY
OVERNIGHT...AND ACROSS THE NORTHERN/WESTERN GREAT LAKES REGION ON
TUESDAY. THIS WILL INDUCE A QUICK RE-TIGHTENING OF THE SURFACE
PRESSURE GRADIENT ACROSS LAKE MICHIGAN TUESDAY MORNING...WITH STRONG
SURFACE-BASED MIXING AND COLD ADVECTION EXPECTED TO PRODUCE WESTERLY
40 KT GALES BASED ON MODEL FORECAST SOUNDINGS. GALES LOOK TO PERSIST
INTO TUESDAY EVENING ACROSS THE SOUTH HALF OF THE LAKE...AND PAST
MIDNIGHT FARTHER NORTH. HIGH PRESSURE THEN BUILDS SOUTHEAST FROM THE
CENTRAL PLAINS THROUGH THE MID/LOWER MISSOURI AND LOWER OHIO RIVER
VALLEYS WEDNESDAY AND WEDNESDAY NIGHT...ALLOWING GALES TO EASE
THOUGH WINDS REMAIN WESTERLY IN THE 20-30 KT RANGE IN THE TIGHTER
GRADIENT NORTH OF THE SURFACE HIGH AND SOUTH OF LOW PRESSURE WHICH
LINGERS OVER HUDSON BAY. WEST WINDS WILL LINGER THROUGH THURSDAY AS
THE HIGH SPREADS EAST THROUGH THE OHIO VALLEY...AND ANOTHER WEAK LOW
CROSSES THE NORTHERN LAKES.
IN THE NEAR TERM...SMALL CRAFT ADVISORIES ARE IN EFFECT FOR THE
ILLINOIS AND INDIANA NEAR SHORE WATERS THROUGH EARLY TUESDAY... WITH
WINDS/WAVES DIMINISHING MORE QUICKLY ALONG THE ILLINOIS SHORE
TONIGHT. THE GALE WARNING TUESDAY/TUESDAY EVENING INCLUDES THE NEAR
SHORE WATERS.
RATZER
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...GALE WARNING...LMZ261-LMZ362-LMZ364-LMZ366-LMZ563-LMZ565 UNTIL 3
AM TUESDAY.
GALE WARNING...LMZ261-LMZ362-LMZ364-LMZ366-LMZ563-LMZ565...4 PM
TUESDAY TO 3 AM WEDNESDAY.
SMALL CRAFT ADVISORY...NEARSHORE GARY TO MICHIGAN CITY IN UNTIL 8 AM TUESDAY.
GALE WARNING...LMZ080-LMZ567-LMZ669-LMZ671-LMZ673-LMZ675-LMZ740-
LMZ741-LMZ742-LMZ743-LMZ744-LMZ745-LMZ777-LMZ779-LMZ868-
LMZ870-LMZ872-LMZ874-LMZ876-LMZ878...8 AM TUESDAY TO 9 PM
TUESDAY.
&&
$$
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 INDIANAPOLIS IN
303 AM EST TUE DEC 10 2013
.UPDATE...
THE LONG TERM SECTION HAS BEEN UPDATED BELOW.
&&
.SYNOPSIS...
ISSUED AT 148 PM EST MON DEC 9 2013
SEVERAL WEAK WEATHER SYSTEMS AFFECT OUR REGION TODAY INTO MIDWEEK
WITH MORE SIGNIFICANT SYSTEM FOR THIS WEEKEND. COLD ARCTIC HIGH
PRESSURE TO RULE IN BETWEEN WITH TEMPERATURES REMAINING WELL BELOW
NORMAL THROUGH EARLY NEXT WEEK.
&&
.NEAR TERM /REST OF TONIGHT/...
ISSUED AT 957 PM EST MON DEC 9 2013
FOR THE LATEST UPDATE...TIMING LOOKS PRETTY GOOD AS ECHOES ARE
STRENGTHENING OVER SOUTHERN ILLINOIS AND OBSERVATIONS OF LIGHT SNOW
ARE BEGINNING TO COME IN FROM THERE. RAP AND HRRR CONTINUE TO SHOW
GOOD DEVELOPMENT OVER THE SOUTHWEST BY AROUND 5-6Z. DID DROP
SNOWFALL AMOUNTS PRIOR TO 6Z WITH SNOW JUST GETTING GOING THEN.
INCREASED VALUES IN THE 6-12Z TIME BASED ON SHORT TERM MODEL OUTPUT.
ALSO NOTED IN THE SHORT TERM GUIDANCE WAS A SLIGHT SHIFT SOUTH IN
THE MEASURABLE PRECIPITATION...BUT WITH THE SHARP GRADIENT ALREADY
IN THE POP GRIDS DID NOT THINK A CHANGE THERE WAS NEEDED. IN SNOW
AMOUNTS THOUGH KEPT SIMILAR VALUES AROUND 1.5 INCHES IN THE SOUTH
BUT DROPPED THEM IN THE NORTH SO THE TERRE HAUTE TO SOUTH INDY TO
RUSHVILLE AREAS SHOULD ONLY SEE A TENTH UP TO A FEW TENTHS OF AN
INCH. CONTINUED WITH EARLIER SPS TO HIGHLIGHT SNOWFALL AND SLICK
CONDITIONS EXPECTED FOR TUESDAY MORNING COMMUTE.
PREVIOUS DISCUSSION FOLLOWS...
CONCERN FOR TONIGHT IS SNOW/NO SNOW BOUNDARY AND HOW MUCH SNOW
WILL OCCUR. WILL NOT ISSUE ADVISORY FOR THIS BUT MAKE MENTION IN
HAZARDOUS WEATHER OUTLOOK AND SPECIAL WEATHER STATEMENT.
AS TAIL END OF FIRST WEAK SHORT WAVE EXITS GREAT LAKES THIS
AFTERNOON THE SECOND ONE OVER THE TX PANHANDLE REGION BEGINS TO
TAKE SHAPE AND AIM ON THE OHIO VALLEY. MODELS IN GOOD AGREEMENT ON
RAPID SPREAD OF NARROW SNOW BAND ENE ACROSS SOUTHERN AND CENTRAL
INDIANA SOUTH OF I-70 LATE EVENING AND OVERNIGHT...QUICKLY EXITING
BEFORE SUNRISE. THOUGH MOISTURE IS SOMEWHAT LIMITED...BRIEF
PERIOD OF DENDRITIC GROWTH MAXES OUT OVER SOUTHERN COUNTIES AND
WITH RATIOS NEAR 15 TO ONE...EXPECT SNOW AMOUNTS OVER ONE INCH BY
DAWN FROM VINCENNES TO BEDFORD-BLOOMINGTON...COLUMBUS AND SEYMOUR.
LOCAL TWO INCH AMOUNTS WILL LIKELY OCCUR. THE CUT-OFF FOR NO SNOW
WILL BE NEARLY PARALLEL AND JUST A BIT NORTH OF I-70 SO SOUTH SIDE
OF INDY METRO COULD SEE HALF INCH WHILE NORTH SIDE GETS JUST A
DUSTING.
CURRENT FORECAST TEMPS NOT BAD BUT WITH BRIEF PERIOD OF PARTIAL
CLEARING THIS EVENING...ESPECIALLY NORTHERN COUNTIES...HAVE
ADJUSTED TEMPS DOWN A COUPLE DEGREES BUT STILL 10-18F RANGE NW TO
SE.
&&
.SHORT TERM /TUESDAY THROUGH THURSDAY/...
ISSUED AT 148 PM EST MON DEC 9 2013
TONIGHT/S SYSTEM WILL BE RAPIDLY EXITING TUESDAY MORNING WITH
GUSTY WEST WINDS AND CLEARING SKIES DEVELOPING IN THE MORNING.
CURRENT MAX TEMPS IN LINE WITH LATEST DATA AND DESPITE SUNSHINE
EXPECT NO BETTER THAN MID TO UPPER 20S.
TUESDAY NIGHT...SKIES BEGIN TO CLOUD OVER ACROSS NORTHERN COUNTIES AS
CLIPPER SYSTEM AND ARCTIC FRONT SWEEPS INTO WESTERN GREAT LAKES BY
DAYBREAK WEDNESDAY. SOUTHERN COUNTIES REMAIN UNDER THE INFLUENCE
OF COLD HIGH PRESSURE AND MAINTAIN MOSTLY CLEAR SKIES. EXPECTING
SIMILAR LOWS WITH READINGS IN 10 TO 15F RANGE.
WEDNESDAY...CURRENTLY LOOKS LIKE THE QUICK CLIPPER SYSTEM/S
MEASURABLE SNOWS WOULD REMAIN NORTH OF A LAFAYETTE TO MUNCIE LINE
AND EVEN THERE AMOUNTS SHOULD BE NO MORE THAN A DUSTING TO HALF
INCH. STRONG ARCTIC HIGH PRESSURE RAPIDLY CLEARS SKIES WEDNESDAY
AFTERNOON AND SETS STAGE FOR CLEAR SKY WEDNESDAY NIGHT WITH SINGLE
DIGIT LOWS AFTER SLOWLY FALLING TEMPS WEDNESDAY AFTERNOON.
HIGH PRESSURE SETTLING INTO THE TENNESSEE VALLEY THURSDAY BRINGS
RETURN FLOW TO SOUTHWEST BUT LITTLE MODERATION OF TEMPS UNDER
SUNNY SKIES. FORECAST MAX TEMPS UPPER TEENS TO LOWER 20S STILL
APPEAR LIKELY.
&&
.LONG TERM /FRIDAY THROUGH MONDAY/...
ISSUED AT 303 AM EST TUE DEC 10 2013
FOCUS IN THE LONG TERM REMAINS ON CHANCES FOR PRECIPITATION
THROUGH THE PERIOD. MODELS ARE IN DECENT AGREEMENT WITH MOST
FEATURES...ALTHOUGH THERE REMAINS SOME DISAGREEMENT ON HOW MUCH
COLD AIR MOVES IN ON SUNDAY. WITH THE UNCERTAINTY INVOLVED STAYED
CLOSE TO ALLBLEND FOR MOST ITEMS.
AN UPPER TROUGH WILL BEGIN ITS APPROACH FRIDAY. MODEL TRENDS HAVE
BEEN TO SLOW DOWN THIS FEATURE...SO SLOWED POPS UNTIL FRIDAY
AFTERNOON. AS THIS TROUGH MOVES INTO AND THROUGH THE AREA FRIDAY
NIGHT INTO SATURDAY NIGHT PRECIPITATION WILL MOVE THROUGH.
THUS WENT HIGH CHANCE OR LIKELY POPS FRIDAY NIGHT INTO
SATURDAY...WITH LOWERING POPS SATURDAY NIGHT AS THE SYSTEM EXITS.
SOME QUESTION ON PATH OF SURFACE LOW AND HOW FAR NORTH WARM AIR
WILL GET. THEREFORE WENT SNOW NORTH 2/3 AND RAIN/SNOW SOUTH 1/3 OF
THE AREA FRIDAY NIGHT AND SATURDAY.
IF LOW GOES FARTHER NORTH PRECIPITATION MAY TURN TO JUST RAIN
ACROSS THE FAR SOUTH. SOME AREAS COULD SEE A FEW INCHES OF SNOW
AS WELL DEPENDING ON TRACK.
SOME COLD ADVECTION AND/OR LAKE EFFECT SNOW SHOWERS MAY IMPACT THE
AREA ON SUNDAY SO WENT LOW POPS ACROSS MAINLY THE NORTHEAST
FORECAST AREA. ANOTHER POTENTIAL SYSTEM COULD MOVE IN FOR
MONDAY...BUT AT THE MOMENT UNCERTAINTY IS TOO HIGH TO MENTION ANY
POPS AT THIS TIME.
&&
.AVIATION /DISCUSSION FOR THE 100600Z TAFS/...
ISSUED AT 1140 PM EST MON DEC 9 2013
SNOW BEGINNING TO REACH THE GROUND OVER SOUTHWEST INDIANA WITH
ASSOCIATED IFR VISIBILITY RESTRICTIONS. LATEST MODEL GUIDANCE
SUGGESTS KBMG WILL SEE THE BEST CHANCES FOR IFR RESTRICTIONS IN SNOW
OVERNIGHT...WITH LIGHTER SNOW AT KIND/KHUF. APPEARS KLAF WILL NOT BE
AFFECTED BY THIS SYSTEM. SYSTEM IS MOVING PRETTY FAST...SO THINK THE
SNOW THREAT WILL END AT THE TAF SITES BY 101100Z.
CEILINGS GENERALLY NEAR OR ABOVE 050 OVERNIGHT EXCEPT IN THE HEAVIER
SNOW AREAS WHERE CEILINGS WILL BE LOWER. LINGERING CEILINGS SHOULD
SCATTER OUT AFTER SUNRISE ON TUESDAY.
MODEL WIND FIELDS SUGGEST SOME SURFACE GUSTS AROUND 25 KTS FROM
240-260 DEGREES WILL DEVELOP AFTER 101600Z.
&&
.IND WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...TUCEK
NEAR TERM...TUCEK/CP
SHORT TERM...TUCEK
LONG TERM....50
AVIATION...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
1140 PM EST MON DEC 9 2013
.UPDATE...
THE AVIATION SECTION HAS BEEN UPDATED BELOW.
&&
.SYNOPSIS...
ISSUED AT 148 PM EST MON DEC 9 2013
SEVERAL WEAK WEATHER SYSTEMS AFFECT OUR REGION TODAY INTO MIDWEEK
WITH MORE SIGNIFICANT SYSTEM FOR THIS WEEKEND. COLD ARCTIC HIGH
PRESSURE TO RULE IN BETWEEN WITH TEMPERATURES REMAINING WELL BELOW
NORMAL THROUGH EARLY NEXT WEEK.
&&
.NEAR TERM /REST OF TONIGHT/...
ISSUED AT 957 PM EST MON DEC 9 2013
FOR THE LATEST UPDATE...TIMING LOOKS PRETTY GOOD AS ECHOES ARE
STRENGTHENING OVER SOUTHERN ILLINOIS AND OBSERVATIONS OF LIGHT SNOW
ARE BEGINNING TO COME IN FROM THERE. RAP AND HRRR CONTINUE TO SHOW
GOOD DEVELOPMENT OVER THE SOUTHWEST BY AROUND 5-6Z. DID DROP
SNOWFALL AMOUNTS PRIOR TO 6Z WITH SNOW JUST GETTING GOING THEN.
INCREASED VALUES IN THE 6-12Z TIME BASED ON SHORT TERM MODEL OUTPUT.
ALSO NOTED IN THE SHORT TERM GUIDANCE WAS A SLIGHT SHIFT SOUTH IN
THE MEASURABLE PRECIPITATION...BUT WITH THE SHARP GRADIENT ALREADY
IN THE POP GRIDS DID NOT THINK A CHANGE THERE WAS NEEDED. IN SNOW
AMOUNTS THOUGH KEPT SIMILAR VALUES AROUND 1.5 INCHES IN THE SOUTH
BUT DROPPED THEM IN THE NORTH SO THE TERRE HAUTE TO SOUTH INDY TO
RUSHVILLE AREAS SHOULD ONLY SEE A TENTH UP TO A FEW TENTHS OF AN
INCH. CONTINUED WITH EARLIER SPS TO HIGHLIGHT SNOWFALL AND SLICK
CONDITIONS EXPECTED FOR TUESDAY MORNING COMMUTE.
PREVIOUS DISCUSSION FOLLOWS...
CONCERN FOR TONIGHT IS SNOW/NO SNOW BOUNDARY AND HOW MUCH SNOW
WILL OCCUR. WILL NOT ISSUE ADVISORY FOR THIS BUT MAKE MENTION IN
HAZARDOUS WEATHER OUTLOOK AND SPECIAL WEATHER STATEMENT.
AS TAIL END OF FIRST WEAK SHORT WAVE EXITS GREAT LAKES THIS
AFTERNOON THE SECOND ONE OVER THE TX PANHANDLE REGION BEGINS TO
TAKE SHAPE AND AIM ON THE OHIO VALLEY. MODELS IN GOOD AGREEMENT ON
RAPID SPREAD OF NARROW SNOW BAND ENE ACROSS SOUTHERN AND CENTRAL
INDIANA SOUTH OF I-70 LATE EVENING AND OVERNIGHT...QUICKLY EXITING
BEFORE SUNRISE. THOUGH MOISTURE IS SOMEWHAT LIMITED...BRIEF
PERIOD OF DENDRITIC GROWTH MAXES OUT OVER SOUTHERN COUNTIES AND
WITH RATIOS NEAR 15 TO ONE...EXPECT SNOW AMOUNTS OVER ONE INCH BY
DAWN FROM VINCENNES TO BEDFORD-BLOOMINGTON...COLUMBUS AND SEYMOUR.
LOCAL TWO INCH AMOUNTS WILL LIKELY OCCUR. THE CUT-OFF FOR NO SNOW
WILL BE NEARLY PARALLEL AND JUST A BIT NORTH OF I-70 SO SOUTH SIDE
OF INDY METRO COULD SEE HALF INCH WHILE NORTH SIDE GETS JUST A
DUSTING.
CURRENT FORECAST TEMPS NOT BAD BUT WITH BRIEF PERIOD OF PARTIAL
CLEARING THIS EVENING...ESPECIALLY NORTHERN COUNTIES...HAVE
ADJUSTED TEMPS DOWN A COUPLE DEGREES BUT STILL 10-18F RANGE NW TO
SE.
&&
.SHORT TERM /TUESDAY THROUGH THURSDAY/...
ISSUED AT 148 PM EST MON DEC 9 2013
TONIGHT/S SYSTEM WILL BE RAPIDLY EXITING TUESDAY MORNING WITH
GUSTY WEST WINDS AND CLEARING SKIES DEVELOPING IN THE MORNING.
CURRENT MAX TEMPS IN LINE WITH LATEST DATA AND DESPITE SUNSHINE
EXPECT NO BETTER THAN MID TO UPPER 20S.
TUESDAY NIGHT...SKIES BEGIN TO CLOUD OVER ACROSS NORTHERN COUNTIES AS
CLIPPER SYSTEM AND ARCTIC FRONT SWEEPS INTO WESTERN GREAT LAKES BY
DAYBREAK WEDNESDAY. SOUTHERN COUNTIES REMAIN UNDER THE INFLUENCE
OF COLD HIGH PRESSURE AND MAINTAIN MOSTLY CLEAR SKIES. EXPECTING
SIMILAR LOWS WITH READINGS IN 10 TO 15F RANGE.
WEDNESDAY...CURRENTLY LOOKS LIKE THE QUICK CLIPPER SYSTEM/S
MEASURABLE SNOWS WOULD REMAIN NORTH OF A LAFAYETTE TO MUNCIE LINE
AND EVEN THERE AMOUNTS SHOULD BE NO MORE THAN A DUSTING TO HALF
INCH. STRONG ARCTIC HIGH PRESSURE RAPIDLY CLEARS SKIES WEDNESDAY
AFTERNOON AND SETS STAGE FOR CLEAR SKY WEDNESDAY NIGHT WITH SINGLE
DIGIT LOWS AFTER SLOWLY FALLING TEMPS WEDNESDAY AFTERNOON.
HIGH PRESSURE SETTLING INTO THE TENNESSEE VALLEY THURSDAY BRINGS
RETURN FLOW TO SOUTHWEST BUT LITTLE MODERATION OF TEMPS UNDER
SUNNY SKIES. FORECAST MAX TEMPS UPPER TEENS TO LOWER 20S STILL
APPEAR LIKELY.
&&
.LONG TERM /THURSDAY NIGHT THROUGH MONDAY/...
ISSUED AT 255 PM EST MON DEC 9 2013
MAIN CHALLENGE FOR THE EXTENDED IS THE ARRIVAL AND IMPACT OF ANOTHER
POTENTIALLY MESSY WINTRY SYSTEM INTO THE OHIO VALLEY FRIDAY NIGHT
AND SATURDAY.
UPPER FLOW PATTERN WILL BRIEFLY TRANSITION FROM THE DEEP TROUGH TO
MORE OF A BROAD SOUTHWEST FLOW. AN UPPER WAVE WILL EJECT OUT OF
NORTHERN MEXICO ON FRIDAY AND QUICKLY TRACK INTO THE OHIO VALLEY BY
SATURDAY. A WEAK SURFACE WAVE WILL DEVELOP OVER THE SOUTHERN ROCKIES
AND MOVE INTO THE TENNESSEE VALLEY ON SATURDAY. THE MODEL
DIFFERENCES DEVELOP WITH RESPECT TO THE TIMING OF THE UPPER WAVE AND
THE STRENGTH OF THE SURFACE LOW. OP GFS CONTINUES TO HOLD THE UPPER
WAVE FURTHER WEST AND BRINGS A STRONGER SURFACE WAVE INTO THE REGION
SATURDAY...WHILE THE GLOBAL MODELS ARE MORE PROGRESSIVE ALOFT WITH A
WEAKER SURFACE WAVE TRACKING FURTHER TO THE SOUTH. THE TRACK AND
INTENSITY OF THE SURFACE WAVE WILL DETERMINE HOW MUCH WARM AIR
WITHIN THE BOUNDARY LAYER CAN BE ADVECTED NORTH INTO THE REGION LATE
FRIDAY NIGHT AND SATURDAY.
AT THIS POINT...AM LEANING TOWARDS THE COOLER GLOBAL MODELS WHICH
LIMIT ANY POTENTIAL MIXING OF PRECIP TO FAR SOUTHERN COUNTIES WHERE
CRITICAL LOW LEVEL THICKNESSES RISE TO AROUND 1305M FOR ABOUT 6-12
HOURS. SHOULD THIS COME TO PASS...SOUNDINGS WOULD SUPPORT FREEZING
RAIN AS THE PREDOMINANT TYPE LATE FRIDAY NIGHT INTO SATURDAY FOR
SEVERAL HOURS. WITH STILL PLENTY OF UNCERTAINTY AT THIS EARLY
STAGE...WILL CARRY A RA/SN MIX OVER THE FAR SOUTH WITH SNOW OVER THE
REST OF THE AREA. ENOUGH MOISTURE ACCOMPANYING THIS SYSTEM THAT
COULD SEE A FEW INCHES OF ACCUM FRIDAY NIGHT/SATURDAY IF PRECIP
REMAINS LARGELY IN THE FORM OF SNOW. WILL CERTAINLY BE KEEPING A
CLOSE EYE ON THE EVOLUTION OF THIS SYSTEM IN THE DAYS TO COME.
BEHIND THE SATURDAY STORM...COLDER AIR WILL ONCE AGAIN RETURN AS THE
POLAR VORTEX PINWHEELS THROUGH THE NORTHERN GREAT LAKES. HIGHS IN
THE 30S FRIDAY AND SATURDAY WILL FALL BACK INTO THE LOWER 20S BY
MONDAY WITH SINGLE DIGIT LOWS RETURNING EARLY NEXT WEEK.
&&
.AVIATION /DISCUSSION FOR THE 100600Z TAFS/...
ISSUED AT 1140 PM EST MON DEC 9 2013
SNOW BEGINNING TO REACH THE GROUND OVER SOUTHWEST INDIANA WITH
ASSOCIATED IFR VISIBILITY RESTRICTIONS. LATEST MODEL GUIDANCE
SUGGESTS KBMG WILL SEE THE BEST CHANCES FOR IFR RESTRICTIONS IN SNOW
OVERNIGHT...WITH LIGHTER SNOW AT KIND/KHUF. APPEARS KLAF WILL NOT BE
AFFECTED BY THIS SYSTEM. SYSTEM IS MOVING PRETTY FAST...SO THINK THE
SNOW THREAT WILL END AT THE TAF SITES BY 101100Z.
CEILINGS GENERALLY NEAR OR ABOVE 050 OVERNIGHT EXCEPT IN THE HEAVIER
SNOW AREAS WHERE CEILINGS WILL BE LOWER. LINGERING CEILINGS SHOULD
SCATTER OUT AFTER SUNRISE ON TUESDAY.
MODEL WIND FIELDS SUGGEST SOME SURFACE GUSTS AROUND 25 KTS FROM
240-260 DEGREES WILL DEVELOP AFTER 101600Z.
&&
.IND WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
SYNOPSIS...TUCEK
NEAR TERM...TUCEK/CP
SHORT TERM...TUCEK
LONG TERM....RYAN
AVIATION...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 DES MOINES IA
208 PM CST TUE DEC 10 2013
.SHORT TERM /TODAY/...
ISSUED AT 353 AM CST TUE DEC 10 2013
MAIN FORECAST CONCERN TODAY IS WITH STRONG WINDS AND LIGHT SNOW
POTENTIAL EARLY THIS MORNING AND ADDITIONAL SNOW CHANCES LATE
THIS AFTERNOON. LEANED TOWARD A BLEND OF THE HOPWRF/NAM12/RAP
THROUGH MIDDAY TODAY...AND THEN NAM12/RAP THIS AFTERNOON.
QUICK MOVING SHORTWAVE AND STRONG PV ANOMALY WILL CONTINUE TO
INCREASE WINDS THIS MORNING AND PROVIDE A BLOWING SNOW POTENTIAL TO
NORTHERN IOWA. LIGHT SNOW IS POSSIBLE THROUGH 12Z/13Z TIME AS
SOUNDINGS LOSE ICE INTRODUCTION AND DEEP MOISTURE OVER THE FAR NORTH
LATER THIS MORNING. WINDS ATOP THE MIXED LAYER NEAR 40 KNOTS AT MCW
AND LIKELY WILL SEE BLSN DUE TO THE FRESH SNOW PACK THROUGH MIDDAY.
WINDS DIMINISH SLIGHTLY THIS AFTERNOON AS PRESSURE GRADIENT
DECREASES. SHORTWAVE QUICKLY DEPARTS THE STATE BY 15Z AND SHOULD SEE
SOME CLEARING LATE THIS MORNING INTO THE EARLY AFTERNOON WITH DRY
AIR ADVECTING INTO THE STATE.
NEXT SHORTWAVE LOOKS TO FOLLOW A SIMILAR TRACK AND AFFECT NORTHERN
IOWA...BUT DIFFERENCE WITH THIS SYSTEM IT HAS MORE MOISTURE AND
FORCING. POPS INCREASE RAPIDLY PAST 21Z TODAY ACROSS THE NORTH AS
NAM AND RAP CONSISTENT ON BRINGING THIS SHORTWAVE INTO THE REGION A
BIT QUICKER. TEMPERATURE TREND TODAY WILL BE TRICKY AS WAA CONTINUES
AHEAD OF THE TROUGH AND KEEPS THEM STEADY OR SLOWLY RISING BEFORE
CAA TAKES OVER BRIEFLY LATE THIS MORNING. THEN MIXING AND SUNSHINE
DOMINATE THIS AFTERNOON WARMING TEMPS AGAIN.
.LONG TERM /TONIGHT THROUGH MONDAY/...
ISSUED AT 353 AM CST TUE DEC 10 2013
THE PRIMARY FORECAST CONCERN WILL BE EARLY IN THE PERIOD. NEXT
SYSTEM WILL ALREADY BE ENTERING NORTHWEST IOWA BY 00Z THIS EVENING
WITH A BAND OF SNOW DEVELOPING. THIS BAND OF SNOW WILL BE FOCUSED
OVER THE NORTHERN HALF OF THE FORECAST AREA THOUGH SOME LIGHT SNOW
MAY FAR ACROSS THE SOUTH AS WELL. THOUGH NOT AS IMPRESSIVE AS
SUNDAY...A RELATIVELY GOOD LOW LEVEL DENDRITIC LAYER DEPTH OF
AROUND 8 KFT. WHILE FORCING WILL BE SPREAD THROUGHOUT A DEEP
LAYER AND WILL RESULT IN AN ARRAY OF FLAKE TYPES...THERE WILL BE A
PERIOD OF HIGH SNOW RATIO DENDRITES. WITH LIQUID EQUIVALENT VALUES
OF GENERALLY ONE TENTH INCH OR LESS WILL RESULT IN SNOWFALL OF 1
TO 2 INCHES ACROSS THE NORTH WITH A MAX CEILING OF 3 INCHES. A
STRONG COLD FRONT WILL SWEEP IN IMMEDIATELY BEHIND THE SNOW AND
WILL BRING ANOTHER ARCTIC SURGE AND GUSTY NORTHWEST WINDS BACK TO
THE STATE. THE COLD AIR AND INCREASING WINDS WILL PRESENT A COUPLE
ISSUES. THE MOST OBVIOUS WILL BE EXPECTED BITTERLY COLD WIND
CHILLS OF -20 TO -30 ACROSS FAR NORTHERN PORTIONS LATE TONIGHT AND
THROUGH MUCH OF WEDNESDAY MORNING. THE SECOND IS THE STRENGTH OF
WINDS AND THE IMPACT ON THE NEWLY FALLEN FLUFFY SNOW AND WHAT WAS
ON THE GROUND FROM SUNDAY. HIGHLY EFFICIENT MOMENTUM TRANSFER OF
MIXED LAYER WINDS WILL BE PRESENT DUE TO THE STRONG COLD
ADVECTION. THIS COMBINED WITH A PERIOD OF GOOD PRESSURE GRADIENT
WITH A STRONG PRESSURE RISE COUPLET WILL LEAD TO STRONGER WINDS
THAN MODELS CURRENTLY SUGGEST. THESE CONDITIONS SHOULD LEAD TO A
PERIOD OF LOW LEVEL BLOWING SNOW WHICH MAY NOT SIGNIFICANTLY
REDUCE VISIBILITIES BUT WILL LEAD TO DETERIORATED ROAD CONDITIONS.
THE SNOW AND BLOWING SNOW LIKELY WILL NOT MEET WINTER WEATHER
ADVISORY CRITERIA ALONG. HOWEVER...THIS LEADS TO A HEADLINE
DECISION QUANDARY. WITH A GOOD CERTAINTY ON THE WIND CHILL
CRITERIA BEING MET...THE BEST OPTION MAY BE TO PACKAGE EVERYTHING
TOGETHER INTO A WINTER WEATHER ADVISORY. WITH IT BEING SECOND
PERIOD...WILL ALLOW THE DAY SHIFT ANOTHER LOOK AS THE SYSTEM
NEARS.
ARCTIC COLD TEMPERATURES CAN BE EXPECTED FOR WEDNESDAY FOLLOWED BY
A QUICK DROP IN THE EVENING A HIGH PRESSURE SLIDES THROUGH WITH
WARM ADVECTION AND RISING TEMPERATURES AFTER MIDNIGHT. WARMER BUT
SEASONABLY COLD FOR THURSDAY. ANOTHER COLD FRONT PASSES THROUGH ON
FRIDAY. THERE IS POTENTIAL FOR THE STATE TO BE IMPACTED BY LIGHT
SNOW WITH THE BOUNDARY ARRIVING FROM THE NORTH. ALSO MOISTURE
STREAMING NORTH FROM THE GULF MAY REACH SOUTHEAST IOWA. THIS
PRECIPITATION COULD FOR A WINTRY MIX WITH A WARM NOSE ALOFT
NUDGING IN BEFORE THE BOUNDARY PUSHES IT SOUTH AGAIN. SIGNS
POINTING TO ANOTHER ARCTIC BLAST AROUND SUNDAY TO END THE PERIOD
QUITE COLD.
&&
.AVIATION...10/18Z
ISSUED AT 203 PM CST TUE DEC 10 2013
MAIN CONCERN WILL BE NEXT CLIPPER MOVING SOUTHEAST TONIGHT ACROSS
REGION. SOME CONCERNS WITH BLSN AND PERIOD OF WIND BEHIND THE
SYSTEM AS IT TRANSITIONS TO THE EAST DURING THE OVERNIGHT AND
EARLY MORNING HOURS. MAIN BAND OF BLSN SHOULD SET UP BETWEEN KFOD
AND JUST SOUTH OF KALO...BUT EVEN AN INCH OR SO OF DRY POWERDY
SNOW MAY CAUSE SOME MINOR BLOWING CONCERNS AT KMCW AS WELL. WITH
SOME CONSISTENCY IN EURO MODEL OVER PAST TWO RUNS WILL REMOVE BLSN
FROM KDSM AS MOST OF SNOW WILL FALL NORTH. WINDS TO DIMINISH AFT
16Z WED...CIGS IMPROVE VERY QUICKLY 2-3 HOURS AFT SYSTEM EXITS.
&&
.DMX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...PODRAZIK
LONG TERM...DONAVON
AVIATION...REV
AREA FORECAST DISCUSSION
NWS DES MOINES IA
605 AM CST TUE DEC 10 2013
...UPDATED AVIATION DISCUSSION...
.SHORT TERM /TODAY/...
ISSUED AT 353 AM CST TUE DEC 10 2013
MAIN FORECAST CONCERN TODAY IS WITH STRONG WINDS AND LIGHT SNOW
POTENTIAL EARLY THIS MORNING AND ADDITIONAL SNOW CHANCES LATE
THIS AFTERNOON. LEANED TOWARD A BLEND OF THE HOPWRF/NAM12/RAP
THROUGH MIDDAY TODAY...AND THEN NAM12/RAP THIS AFTERNOON.
QUICK MOVING SHORTWAVE AND STRONG PV ANOMALY WILL CONTINUE TO
INCREASE WINDS THIS MORNING AND PROVIDE A BLOWING SNOW POTENTIAL TO
NORTHERN IOWA. LIGHT SNOW IS POSSIBLE THROUGH 12Z/13Z TIME AS
SOUNDINGS LOSE ICE INTRODUCTION AND DEEP MOISTURE OVER THE FAR NORTH
LATER THIS MORNING. WINDS ATOP THE MIXED LAYER NEAR 40 KNOTS AT MCW
AND LIKELY WILL SEE BLSN DUE TO THE FRESH SNOW PACK THROUGH MIDDAY.
WINDS DIMINISH SLIGHTLY THIS AFTERNOON AS PRESSURE GRADIENT
DECREASES. SHORTWAVE QUICKLY DEPARTS THE STATE BY 15Z AND SHOULD SEE
SOME CLEARING LATE THIS MORNING INTO THE EARLY AFTERNOON WITH DRY
AIR ADVECTING INTO THE STATE.
NEXT SHORTWAVE LOOKS TO FOLLOW A SIMILAR TRACK AND AFFECT NORTHERN
IOWA...BUT DIFFERENCE WITH THIS SYSTEM IT HAS MORE MOISTURE AND
FORCING. POPS INCREASE RAPIDLY PAST 21Z TODAY ACROSS THE NORTH AS
NAM AND RAP CONSISTENT ON BRINGING THIS SHORTWAVE INTO THE REGION A
BIT QUICKER. TEMPERATURE TREND TODAY WILL BE TRICKY AS WAA CONTINUES
AHEAD OF THE TROUGH AND KEEPS THEM STEADY OR SLOWLY RISING BEFORE
CAA TAKES OVER BRIEFLY LATE THIS MORNING. THEN MIXING AND SUNSHINE
DOMINATE THIS AFTERNOON WARMING TEMPS AGAIN.
.LONG TERM /TONIGHT THROUGH MONDAY/...
ISSUED AT 353 AM CST TUE DEC 10 2013
THE PRIMARY FORECAST CONCERN WILL BE EARLY IN THE PERIOD. NEXT
SYSTEM WILL ALREADY BE ENTERING NORTHWEST IOWA BY 00Z THIS EVENING
WITH A BAND OF SNOW DEVELOPING. THIS BAND OF SNOW WILL BE FOCUSED
OVER THE NORTHERN HALF OF THE FORECAST AREA THOUGH SOME LIGHT SNOW
MAY FAR ACROSS THE SOUTH AS WELL. THOUGH NOT AS IMPRESSIVE AS
SUNDAY...A RELATIVELY GOOD LOW LEVEL DENDRITIC LAYER DEPTH OF
AROUND 8 KFT. WHILE FORCING WILL BE SPREAD THROUGHOUT A DEEP
LAYER AND WILL RESULT IN AN ARRAY OF FLAKE TYPES...THERE WILL BE A
PERIOD OF HIGH SNOW RATIO DENDRITES. WITH LIQUID EQUIVALENT VALUES
OF GENERALLY ONE TENTH INCH OR LESS WILL RESULT IN SNOWFALL OF 1
TO 2 INCHES ACROSS THE NORTH WITH A MAX CEILING OF 3 INCHES. A
STRONG COLD FRONT WILL SWEEP IN IMMEDIATELY BEHIND THE SNOW AND
WILL BRING ANOTHER ARCTIC SURGE AND GUSTY NORTHWEST WINDS BACK TO
THE STATE. THE COLD AIR AND INCREASING WINDS WILL PRESENT A COUPLE
ISSUES. THE MOST OBVIOUS WILL BE EXPECTED BITTERLY COLD WIND
CHILLS OF -20 TO -30 ACROSS FAR NORTHERN PORTIONS LATE TONIGHT AND
THROUGH MUCH OF WEDNESDAY MORNING. THE SECOND IS THE STRENGTH OF
WINDS AND THE IMPACT ON THE NEWLY FALLEN FLUFFY SNOW AND WHAT WAS
ON THE GROUND FROM SUNDAY. HIGHLY EFFICIENT MOMENTUM TRANSFER OF
MIXED LAYER WINDS WILL BE PRESENT DUE TO THE STRONG COLD
ADVECTION. THIS COMBINED WITH A PERIOD OF GOOD PRESSURE GRADIENT
WITH A STRONG PRESSURE RISE COUPLET WILL LEAD TO STRONGER WINDS
THAN MODELS CURRENTLY SUGGEST. THESE CONDITIONS SHOULD LEAD TO A
PERIOD OF LOW LEVEL BLOWING SNOW WHICH MAY NOT SIGNIFICANTLY
REDUCE VISIBILITIES BUT WILL LEAD TO DETERIORATED ROAD CONDITIONS.
THE SNOW AND BLOWING SNOW LIKELY WILL NOT MEET WINTER WEATHER
ADVISORY CRITERIA ALONG. HOWEVER...THIS LEADS TO A HEADLINE
DECISION QUANDARY. WITH A GOOD CERTAINTY ON THE WIND CHILL
CRITERIA BEING MET...THE BEST OPTION MAY BE TO PACKAGE EVERYTHING
TOGETHER INTO A WINTER WEATHER ADVISORY. WITH IT BEING SECOND
PERIOD...WILL ALLOW THE DAY SHIFT ANOTHER LOOK AS THE SYSTEM
NEARS.
ARCTIC COLD TEMPERATURES CAN BE EXPECTED FOR WEDNESDAY FOLLOWED BY
A QUICK DROP IN THE EVENING A HIGH PRESSURE SLIDES THROUGH WITH
WARM ADVECTION AND RISING TEMPERATURES AFTER MIDNIGHT. WARMER BUT
SEASONABLY COLD FOR THURSDAY. ANOTHER COLD FRONT PASSES THROUGH ON
FRIDAY. THERE IS POTENTIAL FOR THE STATE TO BE IMPACTED BY LIGHT
SNOW WITH THE BOUNDARY ARRIVING FROM THE NORTH. ALSO MOISTURE
STREAMING NORTH FROM THE GULF MAY REACH SOUTHEAST IOWA. THIS
PRECIPITATION COULD FOR A WINTRY MIX WITH A WARM NOSE ALOFT
NUDGING IN BEFORE THE BOUNDARY PUSHES IT SOUTH AGAIN. SIGNS
POINTING TO ANOTHER ARCTIC BLAST AROUND SUNDAY TO END THE PERIOD
QUITE COLD.
&&
.AVIATION...10/12Z
ISSUED AT 605 AM CST TUE DEC 10 2013
AREAS OF BLSN WILL CONTINUE TO CAUSE MVFR/IFR VIS THROUGH 14/15Z
THIS MORNING AT ALO/MCW. OTHERWISE...STRONG WINDS WILL CONTINUE
THROUGH MUCH OF THE MORNING HOURS BEFORE DIMINISHING THIS
AFTERNOON. THE SECOND SHORTWAVE WILL BRING SNOW CHANCES THIS
EVENING AND HAVE MENTION OF MVFR CIGS/VIS THIS EVENING AND THEN
MVFR VIS/CIGS DUE TO BLSN OVERNIGHT INTO WED FOR ALO/MCW/FOD.
&&
.DMX WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
SHORT TERM...PODRAZIK
LONG TERM...DONAVON
AVIATION...PODRAZIK
AREA FORECAST DISCUSSION
NWS DES MOINES IA
353 AM CST TUE DEC 10 2013
.SHORT TERM /TODAY/...
ISSUED AT 353 AM CST TUE DEC 10 2013
MAIN FORECAST CONCERN TODAY IS WITH STRONG WINDS AND LIGHT SNOW
POTENTIAL EARLY THIS MORNING AND ADDITIONAL SNOW CHANCES LATE
THIS AFTERNOON. LEANED TOWARD A BLEND OF THE HOPWRF/NAM12/RAP
THROUGH MIDDAY TODAY...AND THEN NAM12/RAP THIS AFTERNOON.
QUICK MOVING SHORTWAVE AND STRONG PV ANOMALY WILL CONTINUE TO
INCREASE WINDS THIS MORNING AND PROVIDE A BLOWING SNOW POTENTIAL TO
NORTHERN IOWA. LIGHT SNOW IS POSSIBLE THROUGH 12Z/13Z TIME AS
SOUNDINGS LOSE ICE INTRODUCTION AND DEEP MOISTURE OVER THE FAR NORTH
LATER THIS MORNING. WINDS ATOP THE MIXED LAYER NEAR 40 KNOTS AT MCW
AND LIKELY WILL SEE BLSN DUE TO THE FRESH SNOW PACK THROUGH MIDDAY.
WINDS DIMINISH SLIGHTLY THIS AFTERNOON AS PRESSURE GRADIENT
DECREASES. SHORTWAVE QUICKLY DEPARTS THE STATE BY 15Z AND SHOULD SEE
SOME CLEARING LATE THIS MORNING INTO THE EARLY AFTERNOON WITH DRY
AIR ADVECTING INTO THE STATE.
NEXT SHORTWAVE LOOKS TO FOLLOW A SIMILAR TRACK AND AFFECT NORTHERN
IOWA...BUT DIFFERENCE WITH THIS SYSTEM IT HAS MORE MOISTURE AND
FORCING. POPS INCREASE RAPIDLY PAST 21Z TODAY ACROSS THE NORTH AS
NAM AND RAP CONSISTENT ON BRINGING THIS SHORTWAVE INTO THE REGION A
BIT QUICKER. TEMPERATURE TREND TODAY WILL BE TRICKY AS WAA CONTINUES
AHEAD OF THE TROUGH AND KEEPS THEM STEADY OR SLOWLY RISING BEFORE
CAA TAKES OVER BRIEFLY LATE THIS MORNING. THEN MIXING AND SUNSHINE
DOMINATE THIS AFTERNOON WARMING TEMPS AGAIN.
.LONG TERM /TONIGHT THROUGH MONDAY/...
ISSUED AT 353 AM CST TUE DEC 10 2013
THE PRIMARY FORECAST CONCERN WILL BE EARLY IN THE PERIOD. NEXT
SYSTEM WILL ALREADY BE ENTERING NORTHWEST IOWA BY 00Z THIS EVENING
WITH A BAND OF SNOW DEVELOPING. THIS BAND OF SNOW WILL BE FOCUSED
OVER THE NORTHERN HALF OF THE FORECAST AREA THOUGH SOME LIGHT SNOW
MAY FAR ACROSS THE SOUTH AS WELL. THOUGH NOT AS IMPRESSIVE AS
SUNDAY...A RELATIVELY GOOD LOW LEVEL DENDRITIC LAYER DEPTH OF
AROUND 8 KFT. WHILE FORCING WILL BE SPREAD THROUGHOUT A DEEP
LAYER AND WILL RESULT IN AN ARRAY OF FLAKE TYPES...THERE WILL BE A
PERIOD OF HIGH SNOW RATIO DENDRITES. WITH LIQUID EQUIVALENT VALUES
OF GENERALLY ONE TENTH INCH OR LESS WILL RESULT IN SNOWFALL OF 1
TO 2 INCHES ACROSS THE NORTH WITH A MAX CEILING OF 3 INCHES. A
STRONG COLD FRONT WILL SWEEP IN IMMEDIATELY BEHIND THE SNOW AND
WILL BRING ANOTHER ARCTIC SURGE AND GUSTY NORTHWEST WINDS BACK TO
THE STATE. THE COLD AIR AND INCREASING WINDS WILL PRESENT A COUPLE
ISSUES. THE MOST OBVIOUS WILL BE EXPECTED BITTERLY COLD WIND
CHILLS OF -20 TO -30 ACROSS FAR NORTHERN PORTIONS LATE TONIGHT AND
THROUGH MUCH OF WEDNESDAY MORNING. THE SECOND IS THE STRENGTH OF
WINDS AND THE IMPACT ON THE NEWLY FALLEN FLUFFY SNOW AND WHAT WAS
ON THE GROUND FROM SUNDAY. HIGHLY EFFICIENT MOMENTUM TRANSFER OF
MIXED LAYER WINDS WILL BE PRESENT DUE TO THE STRONG COLD
ADVECTION. THIS COMBINED WITH A PERIOD OF GOOD PRESSURE GRADIENT
WITH A STRONG PRESSURE RISE COUPLET WILL LEAD TO STRONGER WINDS
THAN MODELS CURRENTLY SUGGEST. THESE CONDITIONS SHOULD LEAD TO A
PERIOD OF LOW LEVEL BLOWING SNOW WHICH MAY NOT SIGNIFICANTLY
REDUCE VISIBILITIES BUT WILL LEAD TO DETERIORATED ROAD CONDITIONS.
THE SNOW AND BLOWING SNOW LIKELY WILL NOT MEET WINTER WEATHER
ADVISORY CRITERIA ALONG. HOWEVER...THIS LEADS TO A HEADLINE
DECISION QUANDARY. WITH A GOOD CERTAINTY ON THE WIND CHILL
CRITERIA BEING MET...THE BEST OPTION MAY BE TO PACKAGE EVERYTHING
TOGETHER INTO A WINTER WEATHER ADVISORY. WITH IT BEING SECOND
PERIOD...WILL ALLOW THE DAY SHIFT ANOTHER LOOK AS THE SYSTEM
NEARS.
ARCTIC COLD TEMPERATURES CAN BE EXPECTED FOR WEDNESDAY FOLLOWED BY
A QUICK DROP IN THE EVENING A HIGH PRESSURE SLIDES THROUGH WITH
WARM ADVECTION AND RISING TEMPERATURES AFTER MIDNIGHT. WARMER BUT
SEASONABLY COLD FOR THURSDAY. ANOTHER COLD FRONT PASSES THROUGH ON
FRIDAY. THERE IS POTENTIAL FOR THE STATE TO BE IMPACTED BY LIGHT
SNOW WITH THE BOUNDARY ARRIVING FROM THE NORTH. ALSO MOISTURE
STREAMING NORTH FROM THE GULF MAY REACH SOUTHEAST IOWA. THIS
PRECIPITATION COULD FOR A WINTRY MIX WITH A WARM NOSE ALOFT
NUDGING IN BEFORE THE BOUNDARY PUSHES IT SOUTH AGAIN. SIGNS
POINTING TO ANOTHER ARCTIC BLAST AROUND SUNDAY TO END THE PERIOD
QUITE COLD.
&&
.AVIATION...10/06Z
ISSUED AT 1148 PM CST MON DEC 9 2013
GUSTY WINDS STILL EXPECTED TO PICK UP LATER TONIGHT...WITH AREAS
OF BLOWING SNOW. POSSIBILITY OF VSBYS DROPPING TO MVFR AND
POSSIBLY IFR AT NORTHERN TAF SITES WHERE WINDS WILL BE STRONGEST
TOWARD SUNRISE TUESDAY TO MID MORNING TUESDAY. WINDS DIMINISH
TOWARD TUESDAY AFTERNOON...WITH ANOTHER SYSTEM PUSHING INTO THE
CWA SPREADING SNOW INTO THE AREA TUESDAY EVENING. HAVE INCLUDED
SNOW MENTION AT NORTHERN TAF SITES...WITH BEST CHANCES FOR SNOW AT
SOUTHERN TAF SITES JUST BEYOND THE CURRENT TAF FORECAST PERIOD.
&&
.DMX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...PODRAZIK
LONG TERM...DONAVON
AVIATION...BEERENDS
AREA FORECAST DISCUSSION
NWS GOODLAND KS
429 PM MST WED DEC 11 2013
.SHORT TERM...(THIS AFTERNOON THROUGH THURSDAY)
ISSUED AT 1258 PM MST WED DEC 11 2013
LATEST WV IMAGERY AND RAP UPPER LEVEL ANALYSIS SHOW NW FLOW STILL IN
PLACE FROM THE NORTHERN ROCKIES AND ACROSS THE CENTRAL PLAINS...WITH
A SHORTWAVE RIDGE ACROSS THE SW US. AT THE SURFACE 1037MB SURFACE
HIGH PRESSURE ENTERED OVER NORTHEASTERN KS AND SOUTHEASTERN NEBRASKA
WITH A LEE TROUGH JUST EAST OF THE FRONT RANGE IN COLORADO. SOUTH TO
SOUTHWEST GRADIENT BETWEEN THESE FEATURES IS IN PLACE OVER OUR
CWA...WHICH HAS SUPPORTED WAA ACROSS WESTERN LOCATIONS AND ABOVE
FREEZING TEMPERATURES ALONG THE CO/KS STATE LINE.
LOW CLOUDS HAVE PRETTY MUCH CLEARED ACROSS ALL BUT THE FAR
NORTHEAST...AND THESE CLOUDS SHOULD CONTINUE TO DISSIPATE AND MOVE
EAST OUT OF THE AREA. WITH SHORTWAVE RIDGING BUILDING NORTH AND EAST
WE WILL SEE DRY CONDITIONS PERSIST. THE MAIN FORECAST CHALLENGE
THROUGH THE SHORT TERM WILL BE HOW WARM TO MAKE TEMPS. AIR MASS WILL
CONTINUE TO MODERATE WITH SW FLOW SUPPORTING GOOD WAA. MODELS SHOW
H85 TEMPS IN THE 5-7C RANGE...WHICH IF THE GOOD MIXING/WARMING
OBSERVED THE LAST FEW DAYS IS ANY INDICATION WE SHOULD SEE HIGHS AT
LEAST IN THE LOW 50S OVER SNOW FREE AREAS. WITH SW WINDS ADVECTING
THESE WARMER TEMPS TOWARDS SNOW COVERED LOCATIONS IN OUR FAR WEST
AND NORTHEAST WE SHOULD SEE CONTINUED DETERIORATION OF THE SNOW
PACK. I AM NOT AS CONFIDENT ABOUT HIGH TEMP ON THURSDAY OVER
MCCOOK/ATWOOD/OBERLIN...BECAUSE OF THIS SNOW PACK. I WOULD NOT BE
SURPRISED IF AFTER TOMORROW THERE IS NO SIGNIFICANT SNOW PACK LEFT
OVER OUR CWA EVEN IN LOCATIONS THAT SAW 4-5" IN THE NORTHEAST.
.LONG TERM...(THURSDAY NIGHT THROUGH NEXT WEDNESDAY)
ISSUED AT 1209 PM MST WED DEC 11 2013
SHORTWAVE TROUGH WILL MOVE ACROSS THE SOUTHERN PLAINS THURSDAY
NIGHT AND FRIDAY. THE SYSTEM WILL BE TOO FAR SOUTH TO BRING A
CHANCE OF PRECIPITATION TO THE LOCAL AREA...HOWEVER IT WILL TAP
INTO SOME SLIGHTLY COOLER AIR FOR FRIDAY AND SATURDAY...WITH
TEMPERATURES 5 TO 10 DEGREES BELOW NORMAL. THE REMAINDER OF THE
LONG TERM PERIOD WILL SEE VARYING DEGREES OF NORTHWEST FLOW ALOFT.
NO PRECIPITATION IS EXPECTED. TEMPERATURES WILL BE MILD WITH HIGHS
MAINLY IN THE 50S THOUGH COULD REACH THE 60S AND POSSIBLY EVEN 70S
IN A FEW LOCATIONS TUESDAY AND WEDNESDAY WITH DOWNSLOPE WARMING.
HOWEVER...ANOTHER ARCTIC OUTBREAK IS LOOMING FOR THE END OF THE
WEEK WITH BITTERLY COLD AIR MASS UPSTREAM WHICH WILL ARRIVE JUST
BEYOND THIS FORECAST PERIOD.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z THURSDAY EVENING)
ISSUED AT 428 PM MST WED DEC 11 2013
VFR CONDITIONS WILL CONTINUE AT KGLD AND KMCK. MIXING SHOULD NOT
BE AS SIGNIFICANT TOMORROW SO WINDS WILL BE LIGHER...GENERALLY 10
KNOTS OR LESS THROUGHOUT THE DAY. WIND DIRECTION WILL BE
SOUTHWESTERLY.
&&
.GLD WATCHES/WARNINGS/ADVISORIES...
KS...NONE.
CO...NONE.
NE...NONE.
&&
$$
SHORT TERM...DR
LONG TERM...024
AVIATION...BRB
AREA FORECAST DISCUSSION
NWS GOODLAND KS
1218 PM MST TUE DEC 10 2013
.SHORT TERM...(TONIGHT AND TOMORROW)
ISSUED AT 1206 PM MST TUE DEC 10 2013
LATEST WV IMAGERY AND RAP H5 UPPER LEVEL ANALYSIS INDICATES NW FLOW
EXTENDING FROM THE THE NORTHERN ROCKIES IN CANADA ACROSS THE GREAT
BASIN AND INTO THE WESTERN PLAINS OF KANSAS. MID-UPPER LEVEL
MOISTURE PLUME ON WV ASSOCIATED WITH MID-HIGH CLOUDS ARE MOVING INTO
THE NEBRASKA PANHANDLE. THIS APPEARS TO BE ALONG THE LEADING EDE OF
AN EMBEDDED SHORTWAVE TROUGH MOVING OUT OF CANADA INTO THE NORTHERN
PLAINS. AT THE SURFACE A WEAK LEE TROUGH HAS DEVELOPED JUST EAST OF
THE FRONT RANGE IN COLORADO WITH A SURFACE TROUGH AXIS EXTENDING
NORTH ACROSS THE NEBRASKA PANHANDLE. SOUTHERLY GRADIENT EXTENDS EAST
ACROSS WESTERN KANSAS AND HAS SUPPORTED GOOD WAA AND MIXING ACROSS
OUR CWA WHERE TEMPS HAVE FINALLY RISEN ABOVE FREEZING FOR THE FIRST
TIME IN 6 DAYS.
DUE TO SNOW PACK BETTER SNOW PACK IN NE PARTS OF OUR CWA MIXING HAS
BEEN LIMITED AND TEMPS HAVE STRUGGLED TO APPROACH FREEZING. THROUGH
THE REST OF THE AFTERNOON WE SHOULD SEE FURTHER DETERIORATION OF
SNOW PACK ACROSS OUR CWA...SO THERE SHOULD BE LESS OF AN IMPACT ON
THE FORECAST FOR MOST OF OUR AREA GOING FORWARD.
TONIGHT...THE SHORTWAVE TROUGH OVER MONTANA WILL SWING SOUTH THEN
EAST ACROSS THE NORTHERN PLAINS PUSHING A BACKDOOR COLD FRONT OVER
OUR CWA. THERE WILL BE SOME WEAK FORCING ACROSS THE NORTHERN PART OF
OUR CWA...HOWEVER WITH A VERY DRY AIR MASS BELOW 12-15KFT I AM NOT
ANTICIPATING ANY MEASURABLE PRECIP. COULDNT RULE OUT A FEW FLURRIES
IN SW NEBRASKA...HOWEVER ITS HARD TO SAY IF THIS WOULD EVEN REACH
THE SURFACE. WITH A COLD AIR SLOSHING BACK OVER OUR CWA TEMPS WILL
COOL OFF ONCE AGAIN...WITH OVERNIGHT LOWS IN THE SINGLE DIGITS.
WINDS AROUND 10-12KTS...CLOUD COVER...AND SLIGHTLY HIGHER SURFACE TD
VALUES SHOULD LIMIT RADIATIONAL COOLING...OTHERWISE WE WOULD HAVE
SEEN ANOTHER NIGHT OF BELOW ZERO TEMPS.
WEDNESDAY...WHILE THE AIR ALOFT WILL BE COOLER THE PATTERN ALOFT
WILL BE MUCH MORE PROGRESSIVE WITH SHORTWAVE RIDGING AND SOUTHERLY
FLOW REDEVELOPING BY LATE AFTERNOON. HIGH TEMPS ARE TRICKY SINCE WE
COULD SEE A GRADIENT OF MID 30S IN THE WEST ASSOCIATED WITH
AFTERNOON WAA AND GOOD MIXING TO MID 20S IN THE NORTHEAST WHERE
COOLER AIR WILL STILL BE IN PLACE.
.LONG TERM...(TOMORROW NIGHT THROUGH NEXT TUESDAY)
ISSUED AT 1206 PM MST TUE DEC 10 2013
THE CENTRAL PLAINS WILL BE UNDER VARYING DEGREES OF NORTHWEST FLOW
ALOFT THROUGH THE ENTIRE PERIOD. NO SIGNIFICANT DISTURBANCES ARE
FORECAST AND DRY CONDITIONS ARE EXPECTED. TEMPERATURES WILL
GENERALLY BE NEAR NORMAL...ALTHOUGH A COUPLE OF BRIEF COLD AIR
INTRUSIONS ARE FORECAST BY THE MODELS. THE FIRST WILL OCCUR FRIDAY
NIGHT AND WILL LOWER TEMPERATURES BY 5-10 DEGREES ON SATURDAY. A
SECOND SHOT OF EVEN COLDER AIR WILL EFFECT MAINLY EASTERN PARTS OF
THE FORECAST AREA ON SUNDAY. MODELS DISAGREE ON HOW FAR WEST TO
BRING THAT SHALLOW AIR MASS THOUGH THE COLD AIR USUALLY WINS IN
THESE SITUATIONS AND HAVE HEDGED TEMPERATURES ON THE COLD SIDE OF
GUIDANCE ESPECIALLY IN THE EAST. BY MONDAY ALL MODELS SHOW THE COLD
AIR SCOURED OUT AND TEMPERATURES REBOUNDING. ANOTHER SLIGHTLY
COOLER GLANCING BLOW MAY OCCUR ON TUESDAY.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z WEDNESDAY AFTERNOON)
ISSUED AT 1030 AM MST TUE DEC 10 2013
VFR CONDITIONS ARE EXPECTED WITH ONLY 15-20KFT CLOUDS MOVING ACROSS
BOTH TERMINALS FROM THE NORTH AS UPPER LEVEL SYSTEM MOVES ACROSS
THE NORTHERN PLAINS. SOUTH WINDS GUSTING 20-25KT ARE EXPECTED AT
KGLD THROUGH MOST OF THIS AFTERNOON. I HAVE LESS CONFIDENCE IN
AFTERNOON WINDS AT KMCK WHERE MIXING IS LIMITED BY BETTER SNOW
PACK. A FRONT WILL MOVE ACROSS THE REGION TONIGHT AND AHEAD OF
THIS FRONT WINDS WILL SHIFT TO THE NORTHWEST AND THEN WEST...AND
REMAIN AROUND 10-12KT THROUGH MOST OF THE NIGHT. HIGH PRESSURE
WILL MOVE BACK OVER BOTH TERMINALS AROUND 10Z WHICH WILL ALLOW
WINDS TO GO LIGHT AND VARIABLE THROUGH THE REST OF THE TAF PERIOD.
&&
.GLD WATCHES/WARNINGS/ADVISORIES...
KS...NONE.
CO...NONE.
NE...NONE.
&&
$$
UPDATE...DR
SHORT TERM...DR
LONG TERM...024
AVIATION...DR
AREA FORECAST DISCUSSION...UPDATED
NWS GRAY ME
632 PM EST WED DEC 11 2013
.SYNOPSIS...
A COLD FRONT WILL DROP SOUTH THROUGH THE REGION TONIGHT. A WEAK
RIDGE OF HIGH PRESSURE WILL BUILD IN FROM THE WEST ON THURSDAY.
LOW PRESSURE MOVING EAST THROUGH SOUTHERN QUEBEC THURSDAY NIGHT
WILL SWING A TRAILING COLD FRONT THROUGH THE REGION ON FRIDAY.
HIGH PRESSURE WILL BUILD IN FROM THE NORTHWEST FRIDAY NIGHT AND
SATURDAY. LOW PRESSURE OVER THE OHIO VALLEY SATURDAY NIGHT WILL
REDEVELOP OFF THE MID ATLANTIC COAST AND WILL MOVE NORTHEAST OFF
THE NEW ENGLAND COAST ON SUNDAY. LOW PRESSURE WILL CONTINUE
NORTHEAST INTO THE MARITIMES SUNDAY NIGHT. HIGH PRESSURE WILL
BUILD IN FROM THE WEST ON MONDAY THEN SHIFT OFFSHORE ON TUESDAY.
&&
.NEAR TERM /UNTIL 6 AM THURSDAY MORNING/...
.UPDATE...
LIGHT UPSLOPE ENHANCED SNOW SHOWERS ARE STILL IN PROGRESS ACROSS
NH AND MAINE ALONG A COLD FRONT. DEW POINT READINGS IN SOUTHERN
CANADA ARE IN THE SINGLE AND NEGATIVE NUMBERS AND WILL DROP
STEADILY OVERNIGHT IN OUR AREA ONCE THE MAIN PUSH OF DRY AIR
BEHIND THE FRONT BEGINS TO FILTER IN.
PERHAPS DUE TO THIS...THE HRRR HAS BACKED OFF ON QPF AND THUS SNOW
AMOUNTS OVERNIGHT...WITH VERY LITTLE PRECIPITATION ONCE THE FRONT
MOVES OFFSHORE AROUND 9 PM. THUS HAVE ADJUSTED AMOUNTS
ACCORDINGLY.
&&
.PREVIOUS DISCUSSION...
INTERESTING TO NOTE...LAKE EFFECT SNOW SHOWERS WILL LIKELY CONTINUE
ACROSS NORTH-CENTRAL NEW HAMPSHIRE. THIS IS DUE TO THE LARGE BAND
EXITING OFF LAKE ONTARIO. THE LATEST HRRR RUN PICKS UP ON THIS
BAND DURING THE EVENING HOURS...BEFORE WEAKENING IT AND MOVING IT
TO THE SOUTH. ANOTHER BAND OF SNOW SHOWERS ASSOCIATED WITH THE
ARCTIC FRONT WILL LIKELY ENTER MAINE FROM CANADA AROUND 23Z.
ISOLATED SQUALLS ARE POSSIBLE WITH THIS ACTIVE SYSTEM AND WILL
NEED TO BE MONITORED CLOSELY THIS EVENING.
THE MUCH ANTICIPATED ARCTIC FRONT WILL FINALLY CROSS THE REGION
TONIGHT...BRING VERY COLD TEMPERATURES. WITH A NORTHWEST
BREEZE...FAR NORTHERN AREAS WILL RECEIVE WIND CHILL ADVISORY
CONDITIONS IN THE -20C AND COLDER RANGE. THUS...WILL BE POSTING
ADVISORIES FOR THE NORTHERN MOUNTAINS THROUGH EARLY THURSDAY MORNING.
TEMPERATURES WILL FALL TO NEAR ZERO IN THE NORTH WITH THE
CONTINUING NORTHWEST WIND.
&&
.SHORT TERM /6 AM THURSDAY MORNING THROUGH THURSDAY NIGHT/...
A WEAK RIDGE OF HIGH PRESSURE WILL PARK ITSELF OVER NORTHERN NEW
ENGLAND THURSDAY. HOWEVER...CLOUDS WILL BE ON THE INCREASE ONCE
AGAIN DURING THE AFTERNOON IN THE NORTH AND MOUNTAINS AS ANOTHER
CLIPPER TYPE SYSTEM QUICKLY APPROACHES FROM CANADA.
THURSDAY NIGHT WILL BE ALMOST A CARBON COPY OF TONIGHT...WITH
SCATTERED SNOW SHOWERS ALONG THE FRONT BY THE EARLY MORNING HOURS.
MORE UPSLOPE SNOW SHOWERS WILL LIKELY FOLLOW. THIS NEXT SHOT OF
COLD AIR WILL BE JUST AS COLD...IF NOT COLDER...THAN THE FIRST
SHOT.
&&
.LONG TERM /FRIDAY THROUGH WEDNESDAY/...
WEAK TROUGH MOVING THROUGH THE REGION FRIDAY WILL LIKELY ONLY
RESULT IN SOME SNOW SHOWERS OVER THE MOUNTAINS. HIGH PRESSURE
MOVES IN FROM THE NORTH FRIDAY NIGHT AND SATURDAY...BRINGING MUCH
COLDER TEMPERATURES TO THE REGION. THIS WILL SET THE STAGE FOR A
POSSIBLE STORM SATURDAY NIGHT AND SUNDAY.
MODELS ARE INDICATING A COASTAL LOW DEVELOPING OVER THE MID-
ATLANTIC STATES SATURDAY NIGHT AND ACROSS THE GULF OF MAINE ON
SUNDAY. THE 12Z GFS HAS BEEN FURTHER EAST WITH THIS SYSTEM AND
TAKES THE LOW OUTSIDE OF THE BENCHMARK...WHILE THE 12Z EURO IS
TAKING THE LOW ALMOST DIRECTLY OVER THE BENCHMARK. EVEN
STILL...THE TREND IN THE EURO HAS BEEN FARTHER EAST WITH EACH RUN.
EVEN IF THE SYSTEM REMAINS WELL OFFSHORE THERE COULD BE ENOUGH
WRAP AROUND MOISTURE TO PRODUCE SEVERAL INCHES OF SNOW OVER
SOUTHERN MAINE AND NEW HAMPSHIRE. COLD AIR ENTRENCHED AT THE
SURFACE SHOULD ENSURE THAT THIS WILL BE AN ALL SNOW EVENT WITH
NOTHING IN THE WAY OF ICE OR RAIN. THE EURO IS ALSO INDICATING
ANOTHER COMPLICATING FACTOR...THE EMERGENCE OF AN INVERTED TROUGH
EXTENDING FROM THE GULF OF MAINE BACK ACROSS LAKE ONTARIO. WILL
DEFINITELY NEED TO WATCH THIS SYSTEM AS WE MOVE INTO THE WEEKEND.
ONCE THE LOW CLEARS THE REGION LATE SUNDAY...RELATIVELY QUIET
WEATHER WILL DOMINATE THE REMAINDER OF THE FORECAST PERIOD.
&&
.AVIATION /23Z WEDNESDAY THROUGH MONDAY/...
SHORT TERM...VFR TONIGHT WITH AREAS OF MVFR CEILINGS AND VSBY
POSSIBLE IN THE MOUNTAINS IN ANY SNOW SHOWERS. VFR THURSDAY AND
THURSDAY NIGHT.
LONG TERM...MAINLY VFR FRIDAY AND SATURDAY. IFR/LIFR CIGS AND
VSBYS WILL DEVELOP SATURDAY NIGHT AND SUNDAY AS A STRONG SYSTEM
MOVES THROUGH THE REGION.
&&
.MARINE...
SHORT TERM...MINIMAL GALES WILL CONTINUE FOR THE OUTER WATERS FOR
TONIGHT WITH SCAS IN THE BAYS.
LONG TERM...WILL LIKELY NEED AT LEAST SMALL CRAFT ADVISORIES FOR
SATURDAY AND SUNDAY AS LOW PRESSURE TRACKS THROUGH THE GULF OF MAINE.
&&
.GYX WATCHES/WARNINGS/ADVISORIES...
ME...WIND CHILL ADVISORY FROM 1 AM TO 8 AM EST THURSDAY FOR
MEZ007>009.
NH...WIND CHILL ADVISORY FROM 1 AM TO 8 AM EST THURSDAY FOR NHZ001.
MARINE...SMALL CRAFT ADVISORY UNTIL 6 AM EST THURSDAY FOR ANZ151-153.
GALE WARNING UNTIL 1 AM EST THURSDAY FOR ANZ150-152-154.
&&
$$
UPDATE...HANES
AREA FORECAST DISCUSSION
NWS BALTIMORE MD/WASHINGTON DC
853 AM EST TUE DEC 10 2013
.SYNOPSIS...
A POTENT UPPER-LEVEL DISTURBANCE WILL PASS THROUGH THE REGION
TODAY. ARCTIC HIGH PRESSURE WILL BUILD OVERHEAD TONIGHT THROUGH
THE END OF THE WEEK. LOW PRESSURE MAY IMPACT THE REGION THIS
WEEKEND.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
UPDATE TO UPGRADE THE WINTER WEATHER ADVISORY TO A WINTER STORM
WARNING FOR PORTIONS OF WESTERN MARYLAND...THE NORTHERN SHENANDOAH
VALLEY OF VIRGINIA AND THE EASTERN WEST VIRGINIA PANHANDLE. THERE
HAVE BEEN REPORTS OF 3 TO 5 INCHES OF SNOW. THE HEAVIEST SNOW HAS
DISSIPATED...BUT AN ADDITIONAL INCH OR TWO OF SNOW IS EXPECTED
THROUGH EARLY AFTERNOON. THE PREVIOUS DISCUSSION FOLLOWS...
LTST SFC ANALY DEPICT LOPRES IN WRN VA/NC. LOW A SFC REFLECTION OF
VORTMAX/RRQ OF 180 KT UPR JET. ASSOCD PCPN HAS RAPIDLY BEEN FILLING
IN ACRS THE OH/TN VLYS...AND IS ON THE WRN DOORSTEP ATTM. GDNC IN
GOOD AGREEMENT THAT THIS WL BE TRACKING ACRS CWFA...PRIMARILY BTWN
12-18 UTC.
THE ARRIVAL OF THIS PCPN WL PROVIDE ENUF MIXING TO ERODE FOG
CURRENTLY IN PLACE. A STRIP OF DENSE FOG RESIDES FM CHO-IAD. TRENDS
SINCE 04Z INDICATE A SLOW IMPRVMNT HAS BEGUN...AND HV ALLWD DENSE
FOG ADVY TO EXPIRE AT 08Z. AFTER THAT...VSBY STILL WONT BE
GREAT...AS FOG RESTRICTIONS WL BE REPLACED W/ SNOW RESTRICTIONS.
THE FEATURES RESPONSIBLE FOR THE SNOW LOOK TO BE PROGRESSIVE.
BUT...LIFT VIGOROUS AND H7-5 F-VECTORS DO POINT TO MESOSCALE
BANDING. WHILE MAX LIFT NOT EXACTLY IN DENTRITIC GROWTH ZONE...A
THIRD TO HALF INCH LIQ QPF SUGGESTS THAT WRNG CRITERIA THREATENED.
CANNOT PLACE EXACTLY WHERE THE BANDS WL SET UP /LTST HRRR AND WRF
RUNS SUGGEST CHO-DCA-MTN/...FEEL FAIRLY CONFIDENT THAT LCLLY HIER
AMTS PSBL. GFS SUGGESTS THAT THE BAND MAY BE NW OF CURRENT 3-6
INCH FCST STRIPE. CONFIDENCE DIMINISHES TWD EZF AND SRN MD DUE TO
LOWER SNW RATIOS AND MDL SNDGS SUGGESTING PL WL MIX IN. BOTH OF
THESE FACTORS WL REDUCE SNW TTLS.
IN LIGHT OF 00Z GDNC...POTL FOR HIER TTLS...AND NOT CERTAIN BANDS
WL BE W/IN PREVIOUS WRNG AREA...HV OPTED TO WIDEN WRNG AREA TO INCL
LUA-FDK ON THE NW AND CHO- OMH ON THE SE. TIME FRAME NOT EXTENDED
AS GDNC STILL PRETTY INSISTENT THAT SNOW SHUD BE ENDING BY 18Z.
MAY EVEN SEE BRIGHTENING SKIES BEFORE SUNSET. ONCE SNOW
STARTS...TEMPS CHGG LTL...AND FCST MAXT REFLECTS THAT.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH WEDNESDAY NIGHT/...
HIPRES BLDS TNGT...WL BE ARND THRU WED NGT. SUBSIDENCE INCREASES
RAPIDLY...PROVIDING ONLY A SMALL WINDOW FOR UPSLP SHSN THIS EVNG.
OTRW...MOCLR SKIES AND CAA DOMINATE THE PD. TOOK MOS BLEND FOR
TEMPS.
&&
.LONG TERM /THURSDAY THROUGH MONDAY/...
A LONG WAVE TROUGH SHOULD MOVE OFF THE EAST COAST FRIDAY AS HIGH
PRESSURE MOVES TO OUR SOUTH. A SLIGHT RELIEF IN TEMPERATURES IS
EXPECTED SATURDAY AS RETURN FLOW BRINGS TEMPS IN THE 40S INTO THE
REGION. A COLORADO LOW IS EXPECTED TO FORM MID WEEK AND TRAVEL CLOSE
TO THE GULF STATES BEFORE MAKING A TURN UP THE TN VALLEY AND TOWARDS
THE MID ATLANTIC. BOTH THE GFS AND ECMWF ARE ON BOARD WITH THIS
TREND AND A WINTRY MIX IS EXPECTED AS IT APPROACHES THE MID
ATLANTIC. PTYPE AND TIMING SPECIFICS ARE STILL IN QUESTION. LOW
PRESSURE MOVES TOWARDS NEW ENGLAND SUNDAY AND BREEZY COOLER
CONDITIONS ARE EXPECTED FOR THE MID ATLANTIC.
&&
.AVIATION /14Z TUESDAY THROUGH SATURDAY/...
LIFR STILL WIDESPREAD...BUT FOG SHUD BE LIFTING BEFORE DAWN.
HWVR...VSBY RESTRICTIONS DUE TO FOG WL BE REPLACED BY RESTRICTIONS
DUE TO SNOW. ONSET PRIOR TO 12Z. POOR CONDS WL CONT THRU 18Z.
VFR TNGT-FRI UNDER HIPRES. DIMINISHED CIGS/VSBYS PSBL SAT AHD OF
THE NEXT SYSTEM TO IMPACT THE RGN.
&&
.MARINE...
WNDS BLO 10 KT ATTM. MIXING REMAINS POOR THRU THE DAY. HWVR...AS A
DISTURBANCE GLIDES BY...PROVIDING A PD OF SNOW...PERHAPS MIXED W/ PL
AND A LTL RA IN THE MID BAY...SOME GDNC SUGGESTING WNDS WL PICK UP.
HV NOT FLLWD THAT SOLN ATTM...AND HV CAPPED WNDS AT 15 KT. WL NEED
TO MONITOR IN CASE A SCA REQD.
IN THE WAKE OF THE LOW...COLD AIR WL STREAM IN...PROVIDING A SETUP
FOR MORE FVRBL MIXING. WL KEEP SCA IN PLACE TNGT. WNDS DIMINISH FOR
WED UNDER HIPRES...WHICH WL BE ARND THRU FRI. A DISTURBANCE MOVE
INTO OVR THE WATERS SAT.
&&
.LWX WATCHES/WARNINGS/ADVISORIES...
DC...WINTER STORM WARNING UNTIL 2 PM EST THIS AFTERNOON FOR DCZ001.
MD...WINTER WEATHER ADVISORY UNTIL 2 PM EST THIS AFTERNOON FOR
MDZ016>018-501-502.
WINTER STORM WARNING UNTIL 2 PM EST THIS AFTERNOON FOR
MDZ003>007-009>011-013-014.
VA...WINTER WEATHER ADVISORY UNTIL 2 PM EST THIS AFTERNOON FOR
VAZ025-026-036>038-050-055>057-503-504.
WINTER STORM WARNING UNTIL 2 PM EST THIS AFTERNOON FOR
VAZ027>031-039-040-042-051>054-501-502.
WV...WINTER WEATHER ADVISORY UNTIL 2 PM EST THIS AFTERNOON FOR
WVZ050-051-055-501>506.
WINTER STORM WARNING UNTIL 2 PM EST THIS AFTERNOON FOR WVZ052-
053.
MARINE...SMALL CRAFT ADVISORY FROM 6 PM THIS EVENING TO 6 AM EST
WEDNESDAY FOR ANZ530>543.
&&
$$
SYNOPSIS...HTS
NEAR TERM...HTS
SHORT TERM...HTS
LONG TERM...HAS
AVIATION...HTS
MARINE...HTS
AREA FORECAST DISCUSSION
NWS BALTIMORE MD/WASHINGTON DC
810 AM EST TUE DEC 10 2013
.SYNOPSIS...
A POTENT UPPER-LEVEL DISTURBANCE WILL PASS THROUGH THE REGION
TODAY. ARCTIC HIGH PRESSURE WILL BUILD OVERHEAD TONIGHT THROUGH
THE END OF THE WEEK. LOW PRESSURE MAY IMPACT THE REGION THIS
WEEKEND.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
...UPDATE TO DOWNGRADE THE WINTER STORM WARNING TO AN ADVISORY FOR
THE CENTRAL SHENANDOAH VALLEY INTO CENTRAL VIRGINIA.
ELSEWHERE...THE WINTER WEATHER HEADLINES HAVE NOT CHANGED. THE
HEAVIEST IS EXPECTED TO BE NEAR AND EAST OF THE BLUE RIDGE
MOUNTAINS DURING THE MID TO LATE MORNING HOURS. THE PREVIOUS
DISCUSSION FOLLOWS...
LTST SFC ANALY DEPICT LOPRES IN WRN VA/NC. LOW A SFC REFLECTION OF
VORTMAX/RRQ OF 180 KT UPR JET. ASSOCD PCPN HAS RAPIDLY BEEN FILLING
IN ACRS THE OH/TN VLYS...AND IS ON THE WRN DOORSTEP ATTM. GDNC IN
GOOD AGREEMENT THAT THIS WL BE TRACKING ACRS CWFA...PRIMARILY BTWN
12-18 UTC.
THE ARRIVAL OF THIS PCPN WL PROVIDE ENUF MIXING TO ERODE FOG
CURRENTLY IN PLACE. A STRIP OF DENSE FOG RESIDES FM CHO-IAD. TRENDS
SINCE 04Z INDICATE A SLOW IMPRVMNT HAS BEGUN...AND HV ALLWD DENSE
FOG ADVY TO EXPIRE AT 08Z. AFTER THAT...VSBY STILL WONT BE
GREAT...AS FOG RESTRICTIONS WL BE REPLACED W/ SNOW RESTRICTIONS.
THE FEATURES RESPONSIBLE FOR THE SNOW LOOK TO BE PROGRESSIVE.
BUT...LIFT VIGOROUS AND H7-5 F-VECTORS DO POINT TO MESOSCALE
BANDING. WHILE MAX LIFT NOT EXACTLY IN DENTRITIC GROWTH ZONE...A
THIRD TO HALF INCH LIQ QPF SUGGESTS THAT WRNG CRITERIA THREATENED.
CANNOT PLACE EXACTLY WHERE THE BANDS WL SET UP /LTST HRRR AND WRF
RUNS SUGGEST CHO-DCA-MTN/...FEEL FAIRLY CONFIDENT THAT LCLLY HIER
AMTS PSBL. GFS SUGGESTS THAT THE BAND MAY BE NW OF CURRENT 3-6
INCH FCST STRIPE. CONFIDENCE DIMINISHES TWD EZF AND SRN MD DUE TO
LOWER SNW RATIOS AND MDL SNDGS SUGGESTING PL WL MIX IN. BOTH OF
THESE FACTORS WL REDUCE SNW TTLS.
IN LIGHT OF 00Z GDNC...POTL FOR HIER TTLS...AND NOT CERTAIN BANDS
WL BE W/IN PREVIOUS WRNG AREA...HV OPTED TO WIDEN WRNG AREA TO INCL
LUA-FDK ON THE NW AND CHO- OMH ON THE SE. TIME FRAME NOT EXTENDED
AS GDNC STILL PRETTY INSISTENT THAT SNOW SHUD BE ENDING BY 18Z.
MAY EVEN SEE BRIGHTENING SKIES BEFORE SUNSET. ONCE SNOW
STARTS...TEMPS CHGG LTL...AND FCST MAXT REFLECTS THAT.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH WEDNESDAY NIGHT/...
HIPRES BLDS TNGT...WL BE ARND THRU WED NGT. SUBSIDENCE INCREASES
RAPIDLY...PROVIDING ONLY A SMALL WINDOW FOR UPSLP SHSN THIS EVNG.
OTRW...MOCLR SKIES AND CAA DOMINATE THE PD. TOOK MOS BLEND FOR
TEMPS.
&&
.LONG TERM /THURSDAY THROUGH MONDAY/...
A LONG WAVE TROUGH SHOULD MOVE OFF THE EAST COAST FRIDAY AS HIGH
PRESSURE MOVES TO OUR SOUTH. A SLIGHT RELIEF IN TEMPERATURES IS
EXPECTED SATURDAY AS RETURN FLOW BRINGS TEMPS IN THE 40S INTO THE
REGION. A COLORADO LOW IS EXPECTED TO FORM MID WEEK AND TRAVEL CLOSE
TO THE GULF STATES BEFORE MAKING A TURN UP THE TN VALLEY AND TOWARDS
THE MID ATLANTIC. BOTH THE GFS AND ECMWF ARE ON BOARD WITH THIS
TREND AND A WINTRY MIX IS EXPECTED AS IT APPROACHES THE MID
ATLANTIC. PTYPE AND TIMING SPECIFICS ARE STILL IN QUESTION. LOW
PRESSURE MOVES TOWARDS NEW ENGLAND SUNDAY AND BREEZY COOLER
CONDITIONS ARE EXPECTED FOR THE MID ATLANTIC.
&&
.AVIATION /13Z TUESDAY THROUGH SATURDAY/...
LIFR STILL WIDESPREAD...BUT FOG SHUD BE LIFTING BEFORE DAWN.
HWVR...VSBY RESTRICTIONS DUE TO FOG WL BE REPLACED BY RESTRICTIONS
DUE TO SNOW. ONSET PRIOR TO 12Z. POOR CONDS WL CONT THRU 18Z.
VFR TNGT-FRI UNDER HIPRES. DIMINISHED CIGS/VSBYS PSBL SAT AHD OF
THE NEXT SYSTEM TO IMPACT THE RGN.
&&
.MARINE...
WNDS BLO 10 KT ATTM. MIXING REMAINS POOR THRU THE DAY. HWVR...AS A
DISTURBANCE GLIDES BY...PROVIDING A PD OF SNOW...PERHAPS MIXED W/ PL
AND A LTL RA IN THE MID BAY...SOME GDNC SUGGESTING WNDS WL PICK UP.
HV NOT FLLWD THAT SOLN ATTM...AND HV CAPPED WNDS AT 15 KT. WL NEED
TO MONITOR IN CASE A SCA REQD.
IN THE WAKE OF THE LOW...COLD AIR WL STREAM IN...PROVIDING A SETUP
FOR MORE FVRBL MIXING. WL KEEP SCA IN PLACE TNGT. WNDS DIMINISH FOR
WED UNDER HIPRES...WHICH WL BE ARND THRU FRI. A DISTURBANCE MOVE
INTO OVR THE WATERS SAT.
&&
.LWX WATCHES/WARNINGS/ADVISORIES...
DC...WINTER STORM WARNING UNTIL 2 PM EST THIS AFTERNOON FOR DCZ001.
MD...WINTER WEATHER ADVISORY UNTIL 2 PM EST THIS AFTERNOON FOR
MDZ003-016>018-501-502.
WINTER STORM WARNING UNTIL 2 PM EST THIS AFTERNOON FOR
MDZ004>007-009>011-013-014.
VA...WINTER WEATHER ADVISORY UNTIL 2 PM EST THIS AFTERNOON FOR
VAZ025-026-028-036>038-050-055>057-503-504.
WINTER STORM WARNING UNTIL 2 PM EST THIS AFTERNOON FOR VAZ027-
029>031-039-040-042-051>054-501-502.
WV...WINTER WEATHER ADVISORY UNTIL 2 PM EST THIS AFTERNOON FOR
WVZ050>053-055-501>506.
MARINE...SMALL CRAFT ADVISORY FROM 6 PM THIS EVENING TO 6 AM EST
WEDNESDAY FOR ANZ530>543.
&&
$$
SYNOPSIS...HTS
NEAR TERM...HTS/BJL
SHORT TERM...HTS
LONG TERM...HAS
AVIATION...HTS
MARINE...HTS
AREA FORECAST DISCUSSION
NWS BALTIMORE MD/WASHINGTON DC
319 AM EST TUE DEC 10 2013
.SYNOPSIS...
A POTENT UPPER-LEVEL DISTURBANCE WILL PASS THROUGH THE REGION
TODAY. ARCTIC HIGH PRESSURE WILL BUILD OVERHEAD TONIGHT THROUGH
THE END OF THE WEEK. LOW PRESSURE MAY IMPACT THE REGION THIS
WEEEKND.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
LTST SFC ANALY DEPICT LOPRES IN WRN VA/NC. LOW A SFC REFLECTION OF
VORTMAX/RRQ OF 180 KT UPR JET. ASSOCD PCPN HAS RAPIDLY BEEN FILLING
IN ACRS THE OH/TN VLYS...AND IS ON THE WRN DOORSTEP ATTM. GDNC IN
GOOD AGREEMENT THAT THIS WL BE TRACKING ACRS CWFA...PRIMARILY BTWN
12-18 UTC.
THE ARRIVAL OF THIS PCPN WL PROVIDE ENUF MIXING TO ERODE FOG
CURRENTLY IN PLACE. A STRIP OF DENSE FOG RESIDES FM CHO-IAD. TRENDS
SINCE 04Z INDICATE A SLOW IMPRVMNT HAS BEGUN...AND HV ALLWD DENSE
FOG ADVY TO EXPIRE AT 08Z. AFTER THAT...VSBY STILL WONT BE
GREAT...AS FOG RESTRICTIONS WL BE REPLACED W/ SNOW RESTRICTIONS.
THE FEATURES RESPONSIBLE FOR THE SNOW LOOK TO BE PROGRESSIVE.
BUT...LIFT VIGOROUS AND H7-5 F-VECTORS DO POINT TO MESOSCALE
BANDING. WHILE MAX LIFT NOT EXACTLY IN DENTRITIC GROWTH ZONE...A
THIRD TO HALF INCH LIQ QPF SUGGESTS THAT WRNG CRITERIA THREATENED.
CANNOT PLACE EXACTLY WHERE THE BANDS WL SET UP /LTST HRRR AND WRF
RUNS SUGGEST CHO-DCA-MTN/...FEEL FAIRLY CONFIDENT THAT LCLLY HIER
AMTS PSBL. GFS SUGGESTS THAT THE BAND MAY BE NW OF CURRENT 3-6
INCH FCST STRIPE. CONFIDENCE DIMINISHES TWD EZF AND SRN MD DUE TO
LOWER SNW RATIOS AND MDL SNDGS SUGGESTING PL WL MIX IN. BOTH OF
THESE FACTORS WL REDUCE SNW TTLS.
IN LIGHT OF 00Z GDNC...POTL FOR HIER TTLS...AND NOT CERTAIN BANDS
WL BE W/IN PREVIOUS WRNG AREA...HV OPTED TO WIDEN WRNG AREA TO INCL
LUA-FDK ON THE NW AND CHO- OMH ON THE SE. TIME FRAME NOT EXTENDED
AS GDNC STILL PRETTY INSISTENT THAT SNOW SHUD BE ENDING BY 18Z.
MAY EVEN SEE BRIGHTENING SKIES BEFORE SUNSET. ONCE SNOW
STARTS...TEMPS CHGG LTL...AND FCST MAXT REFLECTS THAT.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH WEDNESDAY NIGHT/...
HIPRES BLDS TNGT...WL BE ARND THRU WED NGT. SUBSIDENCE INCREASES
RAPIDLY...PROVIDING ONLY A SMALL WINDOW FOR UPSLP SHSN THIS EVNG.
OTRW...MOCLR SKIES AND CAA DOMINATE THE PD. TOOK MOS BLEND FOR
TEMPS.
&&
.LONG TERM /THURSDAY THROUGH MONDAY/...
A LONG WAVE TROUGH SHOULD MOVE OFF THE EAST COAST FRIDAY AS HIGH
PRESSURE MOVES TO OUR SOUTH. A SLIGHT RELIEF IN TEMPERATURES IS
EXPECTED SATURDAY AS RETURN FLOW BRINGS TEMPS IN THE 40S INTO THE
REGION. A COLORADO LOW IS EXPECTED TO FORM MID WEEK AND TRAVEL CLOSE
TO THE GULF STATES BEFORE MAKING A TURN UP THE TN VALLEY AND TOWARDS
THE MID ATLANTIC. BOTH THE GFS AND ECMWF ARE ON BOARD WITH THIS
TREND AND A WINTRY MIX IS EXPECTED AS IT APPROACHES THE MID
ATLANTIC. PTYPE AND TIMING SPECIFICS ARE STILL IN QUESTION. LOW
PRESSURE MOVES TOWARDS NEW ENGLAND SUNDAY AND BREEZY COOLER
CONDITIONS ARE EXPECTED FOR THE MID ATLANTIC.
&&
.AVIATION /08Z TUESDAY THROUGH SATURDAY/...
LIFR STILL WIDESPREAD...BUT FOG SHUD BE LIFTING BEFORE DAWN.
HWVR...VSBY RESTRICTIONS DUE TO FOG WL BE REPLACED BY RESTRICTIONS
DUE TO SNOW. ONSET PRIOR TO 12Z. POOR CONDS WL CONT THRU 18Z.
VFR TNGT-FRI UNDER HIPRES. DIMINISHED CIGS/VSBYS PSBL SAT AHD OF
THE NEXT SYSTEM TO IMPACT THE RGN.
&&
.MARINE...
WNDS BLO 10 KT ATTM. MIXING REMAINS POOR THRU THE DAY. HWVR...AS A
DISTURBANCE GLIDES BY...PROVIDING A PD OF SNOW...PERHAPS MIXED W/ PL
AND A LTL RA IN THE MID BAY...SOME GDNC SUGGESTING WNDS WL PICK UP.
HV NOT FLLWD THAT SOLN ATTM...AND HV CAPPED WNDS AT 15 KT. WL NEED
TO MONITOR IN CASE A SCA REQD.
IN THE WAKE OF THE LOW...COLD AIR WL STREAM IN...PROVIDING A SETUP
FOR MORE FVRBL MIXING. WL KEEP SCA IN PLACE TNGT. WNDS DIMINISH FOR
WED UNDER HIPRES...WHICH WL BE ARND THRU FRI. A DISTURBANCE MOVE
INTO OVR THE WATERS SAT.
&&
.LWX WATCHES/WARNINGS/ADVISORIES...
DC...WINTER STORM WARNING UNTIL 2 PM EST THIS AFTERNOON FOR DCZ001.
MD...WINTER WEATHER ADVISORY UNTIL 2 PM EST THIS AFTERNOON FOR
MDZ003-016>018-501-502.
WINTER STORM WARNING UNTIL 2 PM EST THIS AFTERNOON FOR
MDZ004>007-009>011-013-014.
VA...WINTER WEATHER ADVISORY UNTIL 2 PM EST THIS AFTERNOON FOR
VAZ028-055>057-503-504.
WINTER STORM WARNING UNTIL 2 PM EST THIS AFTERNOON FOR
VAZ025>027-029>031-036>040-042-050>054-501-502.
WV...WINTER WEATHER ADVISORY UNTIL 2 PM EST THIS AFTERNOON FOR
WVZ050>053-055-501>506.
MARINE...SMALL CRAFT ADVISORY FROM 6 PM THIS EVENING TO 6 AM EST
WEDNESDAY FOR ANZ530>543.
&&
$$
SYNOPSIS...HTS
NEAR TERM...HTS
SHORT TERM...HTS
LONG TERM...HAS
AVIATION...HTS
MARINE...HTS
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
943 PM EST WED DEC 11 2013
.UPDATE...
ISSUED AT 845 PM EST WED DEC 11 2013
LATEST MQT RADAR SHOWS LES BANDS OVER ERN LK SUP HAVE SHIFTED TO THE
N OF GRAND MARAIS. WITH THE LLVL FLOW EXPECTED TO BACK TO MORE WSW
THRU THE NGT...EXPECT THESE BANDS TO STAY N OF ALGER COUNTY. SO CANX
GOING ADVY FOR THAT COUNTY EARLY. THE HEAVIER BANDS ARE STILL
IMPACTING FAR NRN LUCE COUNTY...SO WL KEEP THE WRNG GOING FOR THAT
AREA FOR NOW EVEN THOUGH WIND TRENDS MAY SHIFT THE BANDS N OF THE
COUNTY BEFORE 12Z. MAY CANX THE HEADLINE FOR THIS COUNTY AS WELL IF
PRESENT TRENDS CONTINUE. STLT IMAGERY ALSO SUGS THE BANDS HAVE
SHIFTED OUT OF ALL BUT FAR NRN ONTONAGON COUNTY. CALL TO A SPOTTER
JUST N OF ONTONAGON INDICATES ONLY LGT SN IS FALLING THERE...WITH
JUST AN INCH OF ACCUMULATION THRU THE DAY AND INTO THE EVNG.
CONSIDERING THE SAME BACKING FLOW THAT SHOULD CAUSE THE LES TO IMPACT
AREAS MAINLY N OF ONTONAGON COUNTY...OPTED TO CANX THE LES ADVY FOR
THAT COUNTY AS WELL.
PRES FALL CENTER ASSOCIATED WITH SHRTWV DIGGING SEWD INTO THE UPR
MIDWEST WL PASS TO THE SW OF UPR MI TNGT...SO EXPECT WINDS WL BE
LIGHTER THAN ORIGINALLY FCST. HI CLDS ASSOCIATED WITH THIS
DISTURBANCE WL PASS OVER AT LEAST THE SW HALF OF THE CWA AND
PROBABLY LIMIT THE DIURNAL TEMP FALL AS WELL SO WIND CHILLS WL
PROBABLY END OF NOT BEING AS HARSH AND MORE MARGINAL FOR ADVY...ARND
-25F INSTEAD OF -30 TO -35. OPTED TO KEEP THE GOING WIND CHILL
HEADLINES DESPITE THE MORE MARGINAL NATURE OF THE STILL HAZARDOUS
COLD.
&&
.SHORT TERM...(THIS EVENING THROUGH THURSDAY)
ISSUED AT 407 PM EST WED DEC 11 2013
TWO MAIN ITEMS OF FOCUS IN THE SHORT TERM PERIOD...THE ONGOING LAKE
EFFECT SNOW AND THE CONTINUED COLD WEATHER.
LARGE NORTHERN STREAM UPPER TROUGH COVERS THE UPPER GREAT LAKES
REGION AT THIS TIME...ALLOWING RAP ANALYZED 850MB TEMPS TO BE
AROUND -24C. AT THE SURFACE...A LAKE INDUCED TROUGH REMAINS OVER
THE FAR EASTERN LAKE...WHILE HIGH PRESSURE CENTERED OVER NORTHERN
MISSOURI IS PUSHING A RIDGE OVER NORTHERN MINNESOTA AND NORTHWEST
WISCONSIN. THE COLD AIR MOVING OVER THE RELATIVELY WARM LAKE
SUPERIOR WATERS CONTINUES TO PRODUCE LAKE EFFECT IN THE WEST TO
NORTHWEST WIND LOCATIONS THIS AFTERNOON. THE 925/850MB TROUGH THAT
WAS OVER THE AREA THIS MORNING HAS ALREADY SHIFTED EAST OF THE CWA
AND STARTED TO BACK THE WINDS IN THE LOWER LEVELS OVER THE WESTERN
CWA. THIS CAN BE SEEN IN THE VISIBLE SATELLITE IMAGERY OVER THE
WEST...AS THE BANDS HAVE STARTED TO BECOME WEST-EAST ORIENTATED.
THESE BACKING WINDS ARE ALSO STARTING TO REACH THE CENTRAL LAKE
WHERE THE BANDS ARE NOW MORE IN A WNW DIRECTION AND WINDS AT
STANNARD ROCK HAVE SHIFTED TO THE WEST. EASTERN ALGER AND NORTHERN
LUCE HAVE SEEN THE MOST SNOW TODAY...WITH REPORTS IN THE 2-8 INCH
RANGE.
THE HIGH PRESSURE RIDGE THAT HAS STARTED TO MOVE INTO THE WESTERN
CWA WILL CONTINUE EAST TONIGHT...WHICH WILL CONTINUE TO BACK WINDS
THIS EVENING...TO MORE OF A WESTERLY DIRECTION OR EVEN
WEST-SOUTHWEST OVER THE WESTERN CWA. THESE BACKING WINDS WILL
LIKELY LEAD TO A MORE DOMINATE BAND SETTING UP OVER THE
WEST (WITH THE HELP OF COASTAL CONVERGENCE)...LIKELY IN A SIMILAR
LOCATION TO WHAT WAS SEEN ON MONDAY. UNLIKE MONDAY...INVERSION
HEIGHTS WILL BE FALLING AND MUCH LOWER DUE TO THE APPROACHING
HIGH PRESSURE RIDGE AND INCREASED SUBSIDENCE. THIS COMPRESSES THE
MOISTURE TO AROUND 5KFT FOR CLOUD TOPS...EVEN THOUGH LAKE INDUCED
EQUILIBRIUM LEVELS REACH 8-9KFT. WHILE THIS OCCURS...IT DOES TRY TO
PUSH THE BETTER LAKE FORCING INTO THE TOP OF THE DGZ...WHICH MAY AID
SNOWFALL SIZE/RATIOS TO BE A LITTLE HIGHER THAN SEEN OVER THE LAST
DAY. WITH THE AIDED CONVERGENCE DUE TO WINDS BACKING TO THE
SOUTHWEST...WOULD THINK THAT WOULD HELP OFFSET SOME OF THE LARGE
SCALE SUBSIDENCE AND LEAD TO DECENT ACCUMULATING SNOWFALL FOR
NORTHERN HOUGHTON COUNTY AND THE SOUTHERN PART OF KEWEENAW COUNTY
TONIGHT. THERE IS SOME QUESTION ON HOW QUICKLY IT WILL MOVE NORTH
AND WHERE/WHEN IT WILL STALL TONIGHT. LOCAL HIRES WRF-ARW RUNS
(WHICH HAVE PERFORMED WELL WITH LOCATIONS OVER THE LAST 24HRS) ARE
DIFFERING ON HOW FAR NORTH IT WILL GO...ALONG WITH THE 12Z NAM...SO
OPTED TO SHOW IT REACHING STOPPING AROUND THE HOUGHTON-MOHAWK AREA.
THEREFORE...DID EXPAND SNOWFALL AMOUNTS FARTHER NORTH AND ALSO THE
LES ADVISORY. WAS TEMPTED TO BUMP UP TO A WARNING SINCE THERE WERE
REPORTS OUT WEST WITH 1 IN/HR SNOWFALL IN THE COLDER AIR AND LESS
DGZ INFLUENCE...BUT WITH INVERSION HEIGHTS BEING LOWER DECIDED TO
KEEP AMOUNTS AT HIGH END ADVISORY. WILL NEED TO KEEP AN EYE ON
THINGS THIS EVENING...AS THERE IS THE POTENTIAL FOR BORDERLINE
WARNING AMOUNTS WHERE THAT BAND SETS UP. HEADING INTO
THURSDAY...SLIGHTLY WARMER 925-850MB TEMPS DOES PUSH MORE OF THE
CLOUD INTO THE DGZ...WHICH COULD AID SNOWFALL RATIOS EVEN WITH THE
CONTINUED LIMITED CLOUD DEPTH (INVERSION STAYS THE SAME). WINDS LOOK
TO VEER TO MORE OF A WEST-NORTHWEST AS THE TROUGH SLIDES SOUTH
AGAIN...SO WOULD EXPECT LESS CONVERGENCE AFFECTING THE KEWEENAW
PENINSULA AND THE STRONG CONVERGENCE BAND TO SHIFT BACK TO THE
SOUTH. AS FOR THE OTHER ADVISORIES...ENDED GOGEBIC/BARAGA AND SRN
HOUGHTON EARLY AND ALSO TRENDED ONTONAGON TO AN EARLIER END TIME
DUE THE STRONGEST BAND JUST BRUSHING THE FAR NORTHERN PART OF THAT
COUNTY.
OVER THE EAST...THE BACKING WINDS HAVE ALREADY STARTED TO PUSH
THE STRONGER BANDS NORTHEAST AND WOULD EXPECT THAT STEADY PUSH
TO CONTINUE THIS EVENING. THIS STEADY PUSH SHOULD LEAD TO MORE
STEADY/WIDESPREAD ACCUMULATIONS...GENERALLY IN THE 2-5IN RANGE.
TIMING OF THE ADVISORY FOR ALGER AND NRN SCHOOLCRAFT LOOKS GOOD AND
MAY BE ABLE TO END THE LUCE WARNING A COUPLE HOURS EARLY OVERNIGHT.
AFTER THESE BANDS PUSH NORTHEAST...WOULD EXPECT SKIES TO CLEAR OUT.
THE WESTERLY (OR EVEN SLIGHTLY WSW) FLOW WILL CONTINUE INTO TOMORROW
MORNING...BEFORE THE TROUGH DROPS TO THE SOUTH AND WINDS SHIFT BACK
TO THE WEST-NORTHWEST. THIS SHOULD BE ENOUGH TO MOVE THE BANDS BACK
ONSHORE. INVERSION HEIGHTS WILL BE A LOT LOWER THAN SEEN TODAY
(RADAR INDICATED OF 10-11KFT THIS AFTN DECREASING TO 6-7KFT LATE
TONIGHT THROUGH TOMORROW AFTERNOON). EVEN SO...ENHANCED CONVERGENCE
ALONG THE NEXT TROUGH COULD BE ENOUGH TO LEAD TO A QUICK COUPLE OF
INCHES THURSDAY AFTERNOON OVER LUCE COUNTY.
AS FOR THE COLD TEMPERATURES...ONLY MADE MINOR TWEAKS TO LOWS
TONIGHT AND WINDS. LOWS ARE A LITTLE TRICKY WITH THE HIGH
PRESSURE RIDGE TRYING TO SLIDE IN AND THE MODELS SHOWING
WINDS STRUGGLING TO DECOUPLE. BASED OFF INTERIOR LOCATIONS
LAST NIGHT FALLING TO 4-7KTS...THINK THAT SEEMS REASONABLE FOR
TONIGHT AND POTENTIALLY A LITTLE LOWER WITH THE HELP OF THE HIGH
PRESSURE RIDGE MOVING IN. EXPECT MOST LOCATIONS TO BE WELL BELOW
ZERO WITH THE COLDEST VALUES CONTINUING OVER THE INTERIOR WEST AND
CENTRAL (LOWS IN THE TEENS BELOW ZERO). WIND CHILL ADVISORY LOOKS
TO BE IN GOOD SHAPE AFTER THE MINOR ADJUSTMENTS AND WILL LEAVE THAT
AS IS. ONE OTHER ITEM TO NOTE IS A WEAK SHORTWAVE DIVING SOUTHEAST
ON THE BACK SIDE OF THE UPPER TROUGH THAT WILL MOVE THROUGH
NORTHERN MINNESOTA THIS EVENING AND INTO WISCONSIN OVERNIGHT. MAIN
INFLUENCE WILL BE SOME MID-HIGH CLOUDS...BUT INDICATIONS ARE THAT
MOST OF THOSE CLOUDS WILL STAY SOUTHWEST OF THE CWA TONIGHT BUT MAY
STREAM OVER DURING THE DAY TOMORROW. AREAS RIGHT ALONG THE WISCONSIN
BORDER WOULD HAVE THE BEST OPPORTUNITY FOR THESE MID CLOUDS...WHICH
COULD LEAD TO TEMPS WARMING SLIGHTLY TOWARDS DAYBREAK.
.LONG TERM...(THURSDAY NIGHT THROUGH WEDNESDAY)
ISSUED AT 430 PM EST WED DEC 11 2013
MODELS CONTINUE TO SUGGEST AN OVERALL COLD PATTERN THRU THE LONG
TERM PORTION OF THE FCST. HOWEVER...WITH CURRENT DEEP EXPANSIVE
POLAR VORTEX CENTERED AROUND HUDSON BAY WEAKENING AND RETREATING N
LATE THIS WEEK THRU AT LEAST THE MIDDLE OF NEXT WEEK...THE COLD WILL
EASE SOME. A VAST SUPPLY OF COLD AIR WILL REMAIN ACROSS CANADA...SO
ANY SHORTWAVE TRACKING ALONG IN THE RELAXING NW FLOW PATTERN WILL BE
ABLE TO BRING A SURGE OF COLDER AIR INTO THE UPPER LAKES. OVER THE
PAST SEVERAL DAYS...MEDIUM RANGE GUIDANCE HAS BEEN PROGRESSIVELY
SLOWER TO BRING WARMING INTO THE UPPER LAKES FOR THIS REASON. LATER
DOWN THE ROAD NEXT WEEK...THERE ARE SUGGESTIONS OF A TEMPORARY SHIFT
IN THE PATTERN TOWARD A DEEPENING TROF OVER THE WRN CONUS AND
DOWNSTREAM BUILDING RIDGE OVER THE SE CONUS/WRN ATLANTIC. THIS WILL
OFFER THE BEST CHANCE OF A WARMUP THAT WOULD OCCUR AROUND THE MIDDLE
NEXT WEEK. HOW MUCH WARMING OCCURS WILL DEPEND ON THE AMPLITUDE AND
LONGITUDE OF THE TROF/RIDGE PATTERN. WHATEVER HAPPENS...ANY WARMING
WILL ONLY BE BRIEF AS LONGER RANGE GUIDANCE POINTS TOWARD
REINTENSIFYING ARCTIC AIR ACROSS WRN/NRN CANADA DUMPING BACK INTO
THE AREA SOMETIME AROUND THE WEEKEND BEFORE CHRISTMAS OR EARLY
CHRISTMAS WEEK. OUTSIDE OF THE AREAS AFFECTED BY LES...DON`T EXPECT
MUCH MORE THAN SOME -SN AT TIMES DURING THE LONG TERM. POSSIBLE
BRIEF PATTERN CHANGE LATER NEXT WEEK COULD OFFER THE POTENTIAL FOR
SOMETHING MORE SUBSTANTIAL IN TERMS OF PCPN.
BEGINNING THU NIGHT...SHORTWAVE PASSING ACROSS NRN ONTARIO WILL SEND
A SFC TROF S THRU THE UPPER LAKES...CAUSING WINDS TO VEER NW OR N BY
FRI MORNING. AS A RESULT...ONGOING WRLY FLOW LES LATE THU AFTN WILL
SPREAD S...AFFECTING MOST IF NOT ALL OF NRN UPPER MI BY FRI MORNING.
ALTHOUGH THERE IS NOT MUCH IN THE WAY OF DEEP LAYER FORCING...PERIOD
OF DEEPER MOISTURE COMBINED WITH CONVERGENCE ALONG TROF SHOULD YIELD
A SHORT PERIOD OF MDT SNOW AND POSSIBLY BRIEF HVY SNOW AS TROF
SWEEPS S THU NIGHT AND FRI MORNING. BEHIND TROF...INVERSION SETTLES
TO AROUND 5-6KFT FRI. LARGER SCALE LOW-LEVEL FLOW ALSO BECOMES MORE
ANTICYCLONIC FRI. ON THE OTHER HAND...DIMINISHING BOUNDARY LAYER
WINDS MAY ALLOW FOR LOCALIZED CONVERGENCE. IN FACT...NAM INDICATES
WINDS VEERING TO ESE OFF ERN UPPER MI DURING THE DAY FRI...
RESULTING IN A ZONE OF ENHANCED CONVERGENCE EXTENDING ACROSS FAR SE
LAKE SUPERIOR TO THE MARQUETTE AREA. WILL BE SOMETHING TO MONITOR.
OTHERWISE...DGZ WILL BEGIN TO BECOME BETTER LOCATED WITHIN THE
CONVECTIVE LAYER AND UPWARD MOTION ZONE...LEADING TO HIGHER SNOW TO
WATER RATIOS. SO...SHOULD BE ABLE TO FLUFF UP SOME DECENT SNOW
ACCUMULATIONS FRI WHERE LES IS MOST PERISTENT (NCNTRL UPPER MI). OUT
W DURING THE DAY...WINDS MAY END UP VEERING ENOUGH TO PUSH MOST OF
THE LES OFFSHORE OF WRN UPPER MI...EXCEPT FOR THE KEWEENAW.
WINDS CONTINUE VEERING TO THE E THEN SE FRI NIGHT/SAT MORNING AS SFC
HIGH PRES CENTER PASSES JUST N OF LAKE SUPERIOR. LES THAT WILL BE
OCCURRING MAINLY INTO NCNTRL UPPER MI THU AFTN WILL THEN SLOWLY
SHIFT...CROSSING THE KEWEENAW PENINSULA FOR A TIME LATER FRI
NIGHT/SAT MORNING. DGZ WILL STILL BE WELL CENTERED IN THE CONVECTIVE
LAYER...SO A FEW INCHES OF FLUFFY SNOW ARE POSSIBLE. IF WINDS VEER
ENOUGH OVER NRN LAKE MI...SOME LIGHT LES MAY AFFECT PORTIONS OF
MENOMINEE COUNTY.
ATTENTION THEN TURNS TO NEXT CLIPPER SHORTWAVE DROPPING THRU THE
UPPER GREAT LAKES SAT NIGHT/SUN. -SN ASSOCIATED WITH FEATURE SHOULD
SPREAD INTO THE AREA SAT AFTN/EVENING...AND IT LOOKS LIKE THERE WILL
BE A QUICK PERIOD OF LAKE ENHANCEMENT OFF LAKE MI IN SOUTHERLY
FLOW...LEADING TO A POTENTIAL ADVY EVENT. A VERY BRIEF SHOT OF
ARCTIC AIR FOLLOWING SYSTEM WILL PROBABLY RESULT IN A SHORT DURATION
BOUT OF MDT TO POSSIBLY HVY LAKE ENHANCED SNOW FOR NORTHWEST AND
NORTHEAST UPPER MI LATE SAT NIGHT/EARLY SUNDAY AS WIND SHIFTS NW. AS
WINDS VEER AROUND TO THE N OR NE WITH SFC HIGH PRES PASSING ACROSS
NRN ONTARIO...LIGHTER LES WILL AGAIN SHIFT TO AFFECT MORE OF NRN
UPPER MI SUN AFTN/EVENING.
FCST IS MUCH MORE UNCERTAIN HEADING INTO MON/TUE AS MEDIUM RANGE
MODELS ARE HAVING TROUBLE WITH SEVERAL SHORTWAVES IN THE WNW FLOW.
GIVEN THE UNCERTAINTY FROM TODAYS MODEL RUNS AND PREVIOUS RUNS...A
SIMPLE CONSENSUS WILL BE UTILIZED MON/TUE. DEPENDING ON
STRENGTH/TRACK OF THE WAVES...THERE MAY BE A COUPLE OF PERIODS OF
WIDESPREAD -SN AS WELL AS LAKE ENHANCEMENT DEPENDING ON WIND
DIRECTION.
HIGH UNCERTAINTY CONTINUES WED AS ECMWF SHOWS THE POSSIBLE MID WEEK
WARMUP ALLUDED TO EARLIER...WHILE THE GFS DUMPS ARCTIC AIR BACK INTO
THE AREA. AT 00Z THU...850MB TEMPS RANGE FROM ROUGHLY AROUND -2C
WITH THE ECWMF TO -20C WITH THE GFS.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z THURSDAY EVENING)
ISSUED AT 622 PM EST WED DEC 11 2013
CMX...AS THE LLVL FLOW BACKS TOWARD SW TNGT WITH PASSAGE OF SFC HI
PRES TO THE S...EXPECT THE HEAVIER SHSN TO SHIFT TO THE N OF THIS
LOCATION. SO TREND TOWARD MVFR CONDITIONS OVERNGT STILL SEEMS ON
TRACK. BUT AS THE WINDS VEER AGAIN MORE TO THE WNW AND TURN GUSTY
ON THU...MORE SHSN/BLSN WL RETURN ALONG WITH IFR TO LIFR CONDITIONS.
FOR KSAW/KIWD...A WSW LLVL FLOW OF DRY UNMODIFIED ARCTIC AIR WL
RESULT IN VFR CONDITIONS THRU TNGT. AS THE FLOW VEERS MORE TO THE
WNW ON THU MRNG...SOME LOWER MVFR CIGS WL LIKELY RETURN TO IWD. BUT
THE DOWNSLOPE NATURE OF THIS FLOW INTO SAW SHOULD RESULT IN
PERSISTENT VFR CONDITIONS THERE.
&&
.MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 407 PM EST WED DEC 11 2013
WEST TO NORTHWEST WINDS OF 20-30KTS WILL WEAKEN SLIGHTLY TONIGHT AS
A HIGH PRESSURE RIDGE BRUSHES THE AREA. A WEAK TROUGH MOVING ACROSS
THE AREA ON THURSDAY WILL SHIFT WINDS TO MORE OF A NORTHWESTERLY
DIRECTION THURSDAY AFTERNOON AND TO THE NORTH THURSDAY NIGHT AS
ANOTHER HIGH PRESSURE RIDGE (THIS TIME FROM CENTRAL CANADA) NOSES
INTO WESTERN LAKE SUPERIOR. THIS RIDGE IS EXPECTED TO WEAKEN THE
WINDS BELOW 20KTS. DEPENDING ON THE STRENGTH OF A LOW MOVING ACROSS
LAKE SUPERIOR ON SATURDAY NIGHT AND SUNDAY AND THE STRENGTH OF THE
LOW MOVING UP THE EAST COAST...COULD SEE A INCREASE IN
NORTHWESTERLY WINDS ON SUNDAY TO 25-30KTS. THIS WILL BE SHORT LIVED
AS ANOTHER HIGH SLIDES INTO THE AREA FOR THE BEGINNING OF THE
UPCOMING WORK WEEK.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
WIND CHILL ADVISORY UNTIL NOON EST /11 AM CST/ THURSDAY FOR
MIZ002-004-005-009>013-084.
LAKE EFFECT SNOW ADVISORY UNTIL 9 AM EST THURSDAY FOR MIZ001-003.
LAKE SUPERIOR...
HEAVY FREEZING SPRAY WARNING UNTIL 6 AM EST /5 AM CST/ THURSDAY
FOR LSZ162-240>245-248>251-266.
HEAVY FREEZING SPRAY WARNING UNTIL 3 PM EST THURSDAY FOR
LSZ263>265.
LAKE MICHIGAN...
NONE.
&&
$$
UPDATE...KC
SHORT TERM...SRF
LONG TERM...ROLFSON
AVIATION...KC
MARINE...SRF
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
847 PM EST WED DEC 11 2013
.UPDATE...
ISSUED AT 845 PM EST WED DEC 11 2013
LATEST MQT RADAR SHOWS LES BANDS OVER ERN LK SUP HAVE SHIFTED TO THE
N OF GRAND MARAIS. WITH THE LLVL FLOW EXPECTED TO BACK TO MORE WSW
THRU THE NGT...EXPECT THESE BANDS TO STAY N OF ALGER COUNTY. SO CANX
GOING ADVY FOR THAT COUNTY EARLY. THE HEAVIER BANDS ARE STILL
IMPACTING FAR NRN LUCE COUNTY...SO WL KEEP THE WRNG GOING FOR THAT
AREA FOR NOW EVEN THOUGH WIND TRENDS MAY SHIFT THE BANDS N OF THE
COUNTY BEFORE 12Z. MAY CANX THE HEADLINE FOR THIS COUNTY AS WELL IF
PRESENT TRENDS CONTINUE. STLT IMAGERY ALSO SUGS THE BANDS HAVE
SHIFTED OUT OF ALL BUT FAR NRN ONTONAGON COUNTY. CALL TO A SPOTTER
JUST N OF ONTONAGON INDICATES ONLY LGT SN IS FALLING THERE...WITH
JUST AN INCH OF ACCUMULATION THRU THE DAY AND INTO THE EVNG.
CONSIDERING THE SAME BACKING FLOW THAT SHOULD CAUSE THE LES TO IMPACT
AREAS MAINLY N OF ONTONAGON COUNTY...OPTED TO CANX THE LES ADVY FOR
THAT COUNTY AS WELL.
PRES FALL CENTER ASSOCIATED WITH SHRTWV DIGGING SEWD INTO THE UPR
MIDWEST WL PASS TO THE SW OF UPR MI TNGT...SO EXPECT WINDS WL BE
LIGHTER THAN ORIGINALLY FCST. HI CLDS ASSOCIATED WITH THIS
DISTURBANCE WL PASS OVER AT LEAST THE SW HALF OF THE CWA AND
PROBABLY LIMIT THE DIURNAL TEMP FALL AS WELL SO WIND CHILLS WL
PROBABLY END OF NOT BEING AS HARSH AND MORE MARGINAL FOR ADVY...ARND
-25F INSTEAD OF -30 TO -35. OPTED TO KEEP THE GOING WIND CHILL
HEADLINES DESPITE THE MORE MARGINAL NATURE OF THE STILL HAZARDOUS
COLD.
&&
.SHORT TERM...(THIS EVENING THROUGH THURSDAY)
ISSUED AT 407 PM EST WED DEC 11 2013
TWO MAIN ITEMS OF FOCUS IN THE SHORT TERM PERIOD...THE ONGOING LAKE
EFFECT SNOW AND THE CONTINUED COLD WEATHER.
LARGE NORTHERN STREAM UPPER TROUGH COVERS THE UPPER GREAT LAKES
REGION AT THIS TIME...ALLOWING RAP ANALYZED 850MB TEMPS TO BE
AROUND -24C. AT THE SURFACE...A LAKE INDUCED TROUGH REMAINS OVER
THE FAR EASTERN LAKE...WHILE HIGH PRESSURE CENTERED OVER NORTHERN
MISSOURI IS PUSHING A RIDGE OVER NORTHERN MINNESOTA AND NORTHWEST
WISCONSIN. THE COLD AIR MOVING OVER THE RELATIVELY WARM LAKE
SUPERIOR WATERS CONTINUES TO PRODUCE LAKE EFFECT IN THE WEST TO
NORTHWEST WIND LOCATIONS THIS AFTERNOON. THE 925/850MB TROUGH THAT
WAS OVER THE AREA THIS MORNING HAS ALREADY SHIFTED EAST OF THE CWA
AND STARTED TO BACK THE WINDS IN THE LOWER LEVELS OVER THE WESTERN
CWA. THIS CAN BE SEEN IN THE VISIBLE SATELLITE IMAGERY OVER THE
WEST...AS THE BANDS HAVE STARTED TO BECOME WEST-EAST ORIENTATED.
THESE BACKING WINDS ARE ALSO STARTING TO REACH THE CENTRAL LAKE
WHERE THE BANDS ARE NOW MORE IN A WNW DIRECTION AND WINDS AT
STANNARD ROCK HAVE SHIFTED TO THE WEST. EASTERN ALGER AND NORTHERN
LUCE HAVE SEEN THE MOST SNOW TODAY...WITH REPORTS IN THE 2-8 INCH
RANGE.
THE HIGH PRESSURE RIDGE THAT HAS STARTED TO MOVE INTO THE WESTERN
CWA WILL CONTINUE EAST TONIGHT...WHICH WILL CONTINUE TO BACK WINDS
THIS EVENING...TO MORE OF A WESTERLY DIRECTION OR EVEN
WEST-SOUTHWEST OVER THE WESTERN CWA. THESE BACKING WINDS WILL
LIKELY LEAD TO A MORE DOMINATE BAND SETTING UP OVER THE
WEST (WITH THE HELP OF COASTAL CONVERGENCE)...LIKELY IN A SIMILAR
LOCATION TO WHAT WAS SEEN ON MONDAY. UNLIKE MONDAY...INVERSION
HEIGHTS WILL BE FALLING AND MUCH LOWER DUE TO THE APPROACHING
HIGH PRESSURE RIDGE AND INCREASED SUBSIDENCE. THIS COMPRESSES THE
MOISTURE TO AROUND 5KFT FOR CLOUD TOPS...EVEN THOUGH LAKE INDUCED
EQUILIBRIUM LEVELS REACH 8-9KFT. WHILE THIS OCCURS...IT DOES TRY TO
PUSH THE BETTER LAKE FORCING INTO THE TOP OF THE DGZ...WHICH MAY AID
SNOWFALL SIZE/RATIOS TO BE A LITTLE HIGHER THAN SEEN OVER THE LAST
DAY. WITH THE AIDED CONVERGENCE DUE TO WINDS BACKING TO THE
SOUTHWEST...WOULD THINK THAT WOULD HELP OFFSET SOME OF THE LARGE
SCALE SUBSIDENCE AND LEAD TO DECENT ACCUMULATING SNOWFALL FOR
NORTHERN HOUGHTON COUNTY AND THE SOUTHERN PART OF KEWEENAW COUNTY
TONIGHT. THERE IS SOME QUESTION ON HOW QUICKLY IT WILL MOVE NORTH
AND WHERE/WHEN IT WILL STALL TONIGHT. LOCAL HIRES WRF-ARW RUNS
(WHICH HAVE PERFORMED WELL WITH LOCATIONS OVER THE LAST 24HRS) ARE
DIFFERING ON HOW FAR NORTH IT WILL GO...ALONG WITH THE 12Z NAM...SO
OPTED TO SHOW IT REACHING STOPPING AROUND THE HOUGHTON-MOHAWK AREA.
THEREFORE...DID EXPAND SNOWFALL AMOUNTS FARTHER NORTH AND ALSO THE
LES ADVISORY. WAS TEMPTED TO BUMP UP TO A WARNING SINCE THERE WERE
REPORTS OUT WEST WITH 1 IN/HR SNOWFALL IN THE COLDER AIR AND LESS
DGZ INFLUENCE...BUT WITH INVERSION HEIGHTS BEING LOWER DECIDED TO
KEEP AMOUNTS AT HIGH END ADVISORY. WILL NEED TO KEEP AN EYE ON
THINGS THIS EVENING...AS THERE IS THE POTENTIAL FOR BORDERLINE
WARNING AMOUNTS WHERE THAT BAND SETS UP. HEADING INTO
THURSDAY...SLIGHTLY WARMER 925-850MB TEMPS DOES PUSH MORE OF THE
CLOUD INTO THE DGZ...WHICH COULD AID SNOWFALL RATIOS EVEN WITH THE
CONTINUED LIMITED CLOUD DEPTH (INVERSION STAYS THE SAME). WINDS LOOK
TO VEER TO MORE OF A WEST-NORTHWEST AS THE TROUGH SLIDES SOUTH
AGAIN...SO WOULD EXPECT LESS CONVERGENCE AFFECTING THE KEWEENAW
PENINSULA AND THE STRONG CONVERGENCE BAND TO SHIFT BACK TO THE
SOUTH. AS FOR THE OTHER ADVISORIES...ENDED GOGEBIC/BARAGA AND SRN
HOUGHTON EARLY AND ALSO TRENDED ONTONAGON TO AN EARLIER END TIME
DUE THE STRONGEST BAND JUST BRUSHING THE FAR NORTHERN PART OF THAT
COUNTY.
OVER THE EAST...THE BACKING WINDS HAVE ALREADY STARTED TO PUSH
THE STRONGER BANDS NORTHEAST AND WOULD EXPECT THAT STEADY PUSH
TO CONTINUE THIS EVENING. THIS STEADY PUSH SHOULD LEAD TO MORE
STEADY/WIDESPREAD ACCUMULATIONS...GENERALLY IN THE 2-5IN RANGE.
TIMING OF THE ADVISORY FOR ALGER AND NRN SCHOOLCRAFT LOOKS GOOD AND
MAY BE ABLE TO END THE LUCE WARNING A COUPLE HOURS EARLY OVERNIGHT.
AFTER THESE BANDS PUSH NORTHEAST...WOULD EXPECT SKIES TO CLEAR OUT.
THE WESTERLY (OR EVEN SLIGHTLY WSW) FLOW WILL CONTINUE INTO TOMORROW
MORNING...BEFORE THE TROUGH DROPS TO THE SOUTH AND WINDS SHIFT BACK
TO THE WEST-NORTHWEST. THIS SHOULD BE ENOUGH TO MOVE THE BANDS BACK
ONSHORE. INVERSION HEIGHTS WILL BE A LOT LOWER THAN SEEN TODAY
(RADAR INDICATED OF 10-11KFT THIS AFTN DECREASING TO 6-7KFT LATE
TONIGHT THROUGH TOMORROW AFTERNOON). EVEN SO...ENHANCED CONVERGENCE
ALONG THE NEXT TROUGH COULD BE ENOUGH TO LEAD TO A QUICK COUPLE OF
INCHES THURSDAY AFTERNOON OVER LUCE COUNTY.
AS FOR THE COLD TEMPERATURES...ONLY MADE MINOR TWEAKS TO LOWS
TONIGHT AND WINDS. LOWS ARE A LITTLE TRICKY WITH THE HIGH
PRESSURE RIDGE TRYING TO SLIDE IN AND THE MODELS SHOWING
WINDS STRUGGLING TO DECOUPLE. BASED OFF INTERIOR LOCATIONS
LAST NIGHT FALLING TO 4-7KTS...THINK THAT SEEMS REASONABLE FOR
TONIGHT AND POTENTIALLY A LITTLE LOWER WITH THE HELP OF THE HIGH
PRESSURE RIDGE MOVING IN. EXPECT MOST LOCATIONS TO BE WELL BELOW
ZERO WITH THE COLDEST VALUES CONTINUING OVER THE INTERIOR WEST AND
CENTRAL (LOWS IN THE TEENS BELOW ZERO). WIND CHILL ADVISORY LOOKS
TO BE IN GOOD SHAPE AFTER THE MINOR ADJUSTMENTS AND WILL LEAVE THAT
AS IS. ONE OTHER ITEM TO NOTE IS A WEAK SHORTWAVE DIVING SOUTHEAST
ON THE BACK SIDE OF THE UPPER TROUGH THAT WILL MOVE THROUGH
NORTHERN MINNESOTA THIS EVENING AND INTO WISCONSIN OVERNIGHT. MAIN
INFLUENCE WILL BE SOME MID-HIGH CLOUDS...BUT INDICATIONS ARE THAT
MOST OF THOSE CLOUDS WILL STAY SOUTHWEST OF THE CWA TONIGHT BUT MAY
STREAM OVER DURING THE DAY TOMORROW. AREAS RIGHT ALONG THE WISCONSIN
BORDER WOULD HAVE THE BEST OPPORTUNITY FOR THESE MID CLOUDS...WHICH
COULD LEAD TO TEMPS WARMING SLIGHTLY TOWARDS DAYBREAK.
.LONG TERM...(THURSDAY NIGHT THROUGH WEDNESDAY)
ISSUED AT 430 PM EST WED DEC 11 2013
MODELS CONTINUE TO SUGGEST AN OVERALL COLD PATTERN THRU THE LONG
TERM PORTION OF THE FCST. HOWEVER...WITH CURRENT DEEP EXPANSIVE
POLAR VORTEX CENTERED AROUND HUDSON BAY WEAKENING AND RETREATING N
LATE THIS WEEK THRU AT LEAST THE MIDDLE OF NEXT WEEK...THE COLD WILL
EASE SOME. A VAST SUPPLY OF COLD AIR WILL REMAIN ACROSS CANADA...SO
ANY SHORTWAVE TRACKING ALONG IN THE RELAXING NW FLOW PATTERN WILL BE
ABLE TO BRING A SURGE OF COLDER AIR INTO THE UPPER LAKES. OVER THE
PAST SEVERAL DAYS...MEDIUM RANGE GUIDANCE HAS BEEN PROGRESSIVELY
SLOWER TO BRING WARMING INTO THE UPPER LAKES FOR THIS REASON. LATER
DOWN THE ROAD NEXT WEEK...THERE ARE SUGGESTIONS OF A TEMPORARY SHIFT
IN THE PATTERN TOWARD A DEEPENING TROF OVER THE WRN CONUS AND
DOWNSTREAM BUILDING RIDGE OVER THE SE CONUS/WRN ATLANTIC. THIS WILL
OFFER THE BEST CHANCE OF A WARMUP THAT WOULD OCCUR AROUND THE MIDDLE
NEXT WEEK. HOW MUCH WARMING OCCURS WILL DEPEND ON THE AMPLITUDE AND
LONGITUDE OF THE TROF/RIDGE PATTERN. WHATEVER HAPPENS...ANY WARMING
WILL ONLY BE BRIEF AS LONGER RANGE GUIDANCE POINTS TOWARD
REINTENSIFYING ARCTIC AIR ACROSS WRN/NRN CANADA DUMPING BACK INTO
THE AREA SOMETIME AROUND THE WEEKEND BEFORE CHRISTMAS OR EARLY
CHRISTMAS WEEK. OUTSIDE OF THE AREAS AFFECTED BY LES...DON`T EXPECT
MUCH MORE THAN SOME -SN AT TIMES DURING THE LONG TERM. POSSIBLE
BRIEF PATTERN CHANGE LATER NEXT WEEK COULD OFFER THE POTENTIAL FOR
SOMETHING MORE SUBSTANTIAL IN TERMS OF PCPN.
BEGINNING THU NIGHT...SHORTWAVE PASSING ACROSS NRN ONTARIO WILL SEND
A SFC TROF S THRU THE UPPER LAKES...CAUSING WINDS TO VEER NW OR N BY
FRI MORNING. AS A RESULT...ONGOING WRLY FLOW LES LATE THU AFTN WILL
SPREAD S...AFFECTING MOST IF NOT ALL OF NRN UPPER MI BY FRI MORNING.
ALTHOUGH THERE IS NOT MUCH IN THE WAY OF DEEP LAYER FORCING...PERIOD
OF DEEPER MOISTURE COMBINED WITH CONVERGENCE ALONG TROF SHOULD YIELD
A SHORT PERIOD OF MDT SNOW AND POSSIBLY BRIEF HVY SNOW AS TROF
SWEEPS S THU NIGHT AND FRI MORNING. BEHIND TROF...INVERSION SETTLES
TO AROUND 5-6KFT FRI. LARGER SCALE LOW-LEVEL FLOW ALSO BECOMES MORE
ANTICYCLONIC FRI. ON THE OTHER HAND...DIMINISHING BOUNDARY LAYER
WINDS MAY ALLOW FOR LOCALIZED CONVERGENCE. IN FACT...NAM INDICATES
WINDS VEERING TO ESE OFF ERN UPPER MI DURING THE DAY FRI...
RESULTING IN A ZONE OF ENHANCED CONVERGENCE EXTENDING ACROSS FAR SE
LAKE SUPERIOR TO THE MARQUETTE AREA. WILL BE SOMETHING TO MONITOR.
OTHERWISE...DGZ WILL BEGIN TO BECOME BETTER LOCATED WITHIN THE
CONVECTIVE LAYER AND UPWARD MOTION ZONE...LEADING TO HIGHER SNOW TO
WATER RATIOS. SO...SHOULD BE ABLE TO FLUFF UP SOME DECENT SNOW
ACCUMULATIONS FRI WHERE LES IS MOST PERISTENT (NCNTRL UPPER MI). OUT
W DURING THE DAY...WINDS MAY END UP VEERING ENOUGH TO PUSH MOST OF
THE LES OFFSHORE OF WRN UPPER MI...EXCEPT FOR THE KEWEENAW.
WINDS CONTINUE VEERING TO THE E THEN SE FRI NIGHT/SAT MORNING AS SFC
HIGH PRES CENTER PASSES JUST N OF LAKE SUPERIOR. LES THAT WILL BE
OCCURRING MAINLY INTO NCNTRL UPPER MI THU AFTN WILL THEN SLOWLY
SHIFT...CROSSING THE KEWEENAW PENINSULA FOR A TIME LATER FRI
NIGHT/SAT MORNING. DGZ WILL STILL BE WELL CENTERED IN THE CONVECTIVE
LAYER...SO A FEW INCHES OF FLUFFY SNOW ARE POSSIBLE. IF WINDS VEER
ENOUGH OVER NRN LAKE MI...SOME LIGHT LES MAY AFFECT PORTIONS OF
MENOMINEE COUNTY.
ATTENTION THEN TURNS TO NEXT CLIPPER SHORTWAVE DROPPING THRU THE
UPPER GREAT LAKES SAT NIGHT/SUN. -SN ASSOCIATED WITH FEATURE SHOULD
SPREAD INTO THE AREA SAT AFTN/EVENING...AND IT LOOKS LIKE THERE WILL
BE A QUICK PERIOD OF LAKE ENHANCEMENT OFF LAKE MI IN SOUTHERLY
FLOW...LEADING TO A POTENTIAL ADVY EVENT. A VERY BRIEF SHOT OF
ARCTIC AIR FOLLOWING SYSTEM WILL PROBABLY RESULT IN A SHORT DURATION
BOUT OF MDT TO POSSIBLY HVY LAKE ENHANCED SNOW FOR NORTHWEST AND
NORTHEAST UPPER MI LATE SAT NIGHT/EARLY SUNDAY AS WIND SHIFTS NW. AS
WINDS VEER AROUND TO THE N OR NE WITH SFC HIGH PRES PASSING ACROSS
NRN ONTARIO...LIGHTER LES WILL AGAIN SHIFT TO AFFECT MORE OF NRN
UPPER MI SUN AFTN/EVENING.
FCST IS MUCH MORE UNCERTAIN HEADING INTO MON/TUE AS MEDIUM RANGE
MODELS ARE HAVING TROUBLE WITH SEVERAL SHORTWAVES IN THE WNW FLOW.
GIVEN THE UNCERTAINTY FROM TODAYS MODEL RUNS AND PREVIOUS RUNS...A
SIMPLE CONSENSUS WILL BE UTILIZED MON/TUE. DEPENDING ON
STRENGTH/TRACK OF THE WAVES...THERE MAY BE A COUPLE OF PERIODS OF
WIDESPREAD -SN AS WELL AS LAKE ENHANCEMENT DEPENDING ON WIND
DIRECTION.
HIGH UNCERTAINTY CONTINUES WED AS ECMWF SHOWS THE POSSIBLE MID WEEK
WARMUP ALLUDED TO EARLIER...WHILE THE GFS DUMPS ARCTIC AIR BACK INTO
THE AREA. AT 00Z THU...850MB TEMPS RANGE FROM ROUGHLY AROUND -2C
WITH THE ECWMF TO -20C WITH THE GFS.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z THURSDAY EVENING)
ISSUED AT 622 PM EST WED DEC 11 2013
CMX...AS THE LLVL FLOW BACKS TOWARD SW TNGT WITH PASSAGE OF SFC HI
PRES TO THE S...EXPECT THE HEAVIER SHSN TO SHIFT TO THE N OF THIS
LOCATION. SO TREND TOWARD MVFR CONDITIONS OVERNGT STILL SEEMS ON
TRACK. BUT AS THE WINDS VEER AGAIN MORE TO THE WNW AND TURN GUSTY
ON THU...MORE SHSN/BLSN WL RETURN ALONG WITH IFR TO LIFR CONDITIONS.
FOR KSAW/KIWD...A WSW LLVL FLOW OF DRY UNMODIFIED ARCTIC AIR WL
RESULT IN VFR CONDITIONS THRU TNGT. AS THE FLOW VEERS MORE TO THE
WNW ON THU MRNG...SOME LOWER MVFR CIGS WL LIKELY RETURN TO IWD. BUT
THE DOWNSLOPE NATURE OF THIS FLOW INTO SAW SHOULD RESULT IN
PERSISTENT VFR CONDITIONS THERE.
&&
.MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 407 PM EST WED DEC 11 2013
WEST TO NORTHWEST WINDS OF 20-30KTS WILL WEAKEN SLIGHTLY TONIGHT AS
A HIGH PRESSURE RIDGE BRUSHES THE AREA. A WEAK TROUGH MOVING ACROSS
THE AREA ON THURSDAY WILL SHIFT WINDS TO MORE OF A NORTHWESTERLY
DIRECTION THURSDAY AFTERNOON AND TO THE NORTH THURSDAY NIGHT AS
ANOTHER HIGH PRESSURE RIDGE (THIS TIME FROM CENTRAL CANADA) NOSES
INTO WESTERN LAKE SUPERIOR. THIS RIDGE IS EXPECTED TO WEAKEN THE
WINDS BELOW 20KTS. DEPENDING ON THE STRENGTH OF A LOW MOVING ACROSS
LAKE SUPERIOR ON SATURDAY NIGHT AND SUNDAY AND THE STRENGTH OF THE
LOW MOVING UP THE EAST COAST...COULD SEE A INCREASE IN
NORTHWESTERLY WINDS ON SUNDAY TO 25-30KTS. THIS WILL BE SHORT LIVED
AS ANOTHER HIGH SLIDES INTO THE AREA FOR THE BEGINNING OF THE
UPCOMING WORK WEEK.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
WIND CHILL ADVISORY UNTIL NOON EST /11 AM CST/ THURSDAY FOR
MIZ002-004-005-009>013-084.
LAKE EFFECT SNOW ADVISORY UNTIL 9 AM EST THURSDAY FOR MIZ001-003.
LAKE EFFECT SNOW WARNING UNTIL 7 AM EST THURSDAY FOR MIZ007.
LAKE SUPERIOR...
HEAVY FREEZING SPRAY WARNING UNTIL 6 AM EST /5 AM CST/ THURSDAY
FOR LSZ162-240>245-248>251-266.
HEAVY FREEZING SPRAY WARNING UNTIL 3 PM EST THURSDAY FOR
LSZ263>265.
LAKE MICHIGAN...
NONE.
&&
$$
UPDATE...KC
SHORT TERM...SRF
LONG TERM...ROLFSON
AVIATION...KC
MARINE...SRF
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
623 PM EST WED DEC 11 2013
.SHORT TERM...(THIS EVENING THROUGH THURSDAY)
ISSUED AT 407 PM EST WED DEC 11 2013
TWO MAIN ITEMS OF FOCUS IN THE SHORT TERM PERIOD...THE ONGOING LAKE
EFFECT SNOW AND THE CONTINUED COLD WEATHER.
LARGE NORTHERN STREAM UPPER TROUGH COVERS THE UPPER GREAT LAKES
REGION AT THIS TIME...ALLOWING RAP ANALYZED 850MB TEMPS TO BE
AROUND -24C. AT THE SURFACE...A LAKE INDUCED TROUGH REMAINS OVER
THE FAR EASTERN LAKE...WHILE HIGH PRESSURE CENTERED OVER NORTHERN
MISSOURI IS PUSHING A RIDGE OVER NORTHERN MINNESOTA AND NORTHWEST
WISCONSIN. THE COLD AIR MOVING OVER THE RELATIVELY WARM LAKE
SUPERIOR WATERS CONTINUES TO PRODUCE LAKE EFFECT IN THE WEST TO
NORTHWEST WIND LOCATIONS THIS AFTERNOON. THE 925/850MB TROUGH THAT
WAS OVER THE AREA THIS MORNING HAS ALREADY SHIFTED EAST OF THE CWA
AND STARTED TO BACK THE WINDS IN THE LOWER LEVELS OVER THE WESTERN
CWA. THIS CAN BE SEEN IN THE VISIBLE SATELLITE IMAGERY OVER THE
WEST...AS THE BANDS HAVE STARTED TO BECOME WEST-EAST ORIENTATED.
THESE BACKING WINDS ARE ALSO STARTING TO REACH THE CENTRAL LAKE
WHERE THE BANDS ARE NOW MORE IN A WNW DIRECTION AND WINDS AT
STANNARD ROCK HAVE SHIFTED TO THE WEST. EASTERN ALGER AND NORTHERN
LUCE HAVE SEEN THE MOST SNOW TODAY...WITH REPORTS IN THE 2-8 INCH
RANGE.
THE HIGH PRESSURE RIDGE THAT HAS STARTED TO MOVE INTO THE WESTERN
CWA WILL CONTINUE EAST TONIGHT...WHICH WILL CONTINUE TO BACK WINDS
THIS EVENING...TO MORE OF A WESTERLY DIRECTION OR EVEN
WEST-SOUTHWEST OVER THE WESTERN CWA. THESE BACKING WINDS WILL
LIKELY LEAD TO A MORE DOMINATE BAND SETTING UP OVER THE
WEST (WITH THE HELP OF COASTAL CONVERGENCE)...LIKELY IN A SIMILAR
LOCATION TO WHAT WAS SEEN ON MONDAY. UNLIKE MONDAY...INVERSION
HEIGHTS WILL BE FALLING AND MUCH LOWER DUE TO THE APPROACHING
HIGH PRESSURE RIDGE AND INCREASED SUBSIDENCE. THIS COMPRESSES THE
MOISTURE TO AROUND 5KFT FOR CLOUD TOPS...EVEN THOUGH LAKE INDUCED
EQUILIBRIUM LEVELS REACH 8-9KFT. WHILE THIS OCCURS...IT DOES TRY TO
PUSH THE BETTER LAKE FORCING INTO THE TOP OF THE DGZ...WHICH MAY AID
SNOWFALL SIZE/RATIOS TO BE A LITTLE HIGHER THAN SEEN OVER THE LAST
DAY. WITH THE AIDED CONVERGENCE DUE TO WINDS BACKING TO THE
SOUTHWEST...WOULD THINK THAT WOULD HELP OFFSET SOME OF THE LARGE
SCALE SUBSIDENCE AND LEAD TO DECENT ACCUMULATING SNOWFALL FOR
NORTHERN HOUGHTON COUNTY AND THE SOUTHERN PART OF KEWEENAW COUNTY
TONIGHT. THERE IS SOME QUESTION ON HOW QUICKLY IT WILL MOVE NORTH
AND WHERE/WHEN IT WILL STALL TONIGHT. LOCAL HIRES WRF-ARW RUNS
(WHICH HAVE PERFORMED WELL WITH LOCATIONS OVER THE LAST 24HRS) ARE
DIFFERING ON HOW FAR NORTH IT WILL GO...ALONG WITH THE 12Z NAM...SO
OPTED TO SHOW IT REACHING STOPPING AROUND THE HOUGHTON-MOHAWK AREA.
THEREFORE...DID EXPAND SNOWFALL AMOUNTS FARTHER NORTH AND ALSO THE
LES ADVISORY. WAS TEMPTED TO BUMP UP TO A WARNING SINCE THERE WERE
REPORTS OUT WEST WITH 1 IN/HR SNOWFALL IN THE COLDER AIR AND LESS
DGZ INFLUENCE...BUT WITH INVERSION HEIGHTS BEING LOWER DECIDED TO
KEEP AMOUNTS AT HIGH END ADVISORY. WILL NEED TO KEEP AN EYE ON
THINGS THIS EVENING...AS THERE IS THE POTENTIAL FOR BORDERLINE
WARNING AMOUNTS WHERE THAT BAND SETS UP. HEADING INTO
THURSDAY...SLIGHTLY WARMER 925-850MB TEMPS DOES PUSH MORE OF THE
CLOUD INTO THE DGZ...WHICH COULD AID SNOWFALL RATIOS EVEN WITH THE
CONTINUED LIMITED CLOUD DEPTH (INVERSION STAYS THE SAME). WINDS LOOK
TO VEER TO MORE OF A WEST-NORTHWEST AS THE TROUGH SLIDES SOUTH
AGAIN...SO WOULD EXPECT LESS CONVERGENCE AFFECTING THE KEWEENAW
PENINSULA AND THE STRONG CONVERGENCE BAND TO SHIFT BACK TO THE
SOUTH. AS FOR THE OTHER ADVISORIES...ENDED GOGEBIC/BARAGA AND SRN
HOUGHTON EARLY AND ALSO TRENDED ONTONAGON TO AN EARLIER END TIME
DUE THE STRONGEST BAND JUST BRUSHING THE FAR NORTHERN PART OF THAT
COUNTY.
OVER THE EAST...THE BACKING WINDS HAVE ALREADY STARTED TO PUSH
THE STRONGER BANDS NORTHEAST AND WOULD EXPECT THAT STEADY PUSH
TO CONTINUE THIS EVENING. THIS STEADY PUSH SHOULD LEAD TO MORE
STEADY/WIDESPREAD ACCUMULATIONS...GENERALLY IN THE 2-5IN RANGE.
TIMING OF THE ADVISORY FOR ALGER AND NRN SCHOOLCRAFT LOOKS GOOD AND
MAY BE ABLE TO END THE LUCE WARNING A COUPLE HOURS EARLY OVERNIGHT.
AFTER THESE BANDS PUSH NORTHEAST...WOULD EXPECT SKIES TO CLEAR OUT.
THE WESTERLY (OR EVEN SLIGHTLY WSW) FLOW WILL CONTINUE INTO TOMORROW
MORNING...BEFORE THE TROUGH DROPS TO THE SOUTH AND WINDS SHIFT BACK
TO THE WEST-NORTHWEST. THIS SHOULD BE ENOUGH TO MOVE THE BANDS BACK
ONSHORE. INVERSION HEIGHTS WILL BE A LOT LOWER THAN SEEN TODAY
(RADAR INDICATED OF 10-11KFT THIS AFTN DECREASING TO 6-7KFT LATE
TONIGHT THROUGH TOMORROW AFTERNOON). EVEN SO...ENHANCED CONVERGENCE
ALONG THE NEXT TROUGH COULD BE ENOUGH TO LEAD TO A QUICK COUPLE OF
INCHES THURSDAY AFTERNOON OVER LUCE COUNTY.
AS FOR THE COLD TEMPERATURES...ONLY MADE MINOR TWEAKS TO LOWS
TONIGHT AND WINDS. LOWS ARE A LITTLE TRICKY WITH THE HIGH
PRESSURE RIDGE TRYING TO SLIDE IN AND THE MODELS SHOWING
WINDS STRUGGLING TO DECOUPLE. BASED OFF INTERIOR LOCATIONS
LAST NIGHT FALLING TO 4-7KTS...THINK THAT SEEMS REASONABLE FOR
TONIGHT AND POTENTIALLY A LITTLE LOWER WITH THE HELP OF THE HIGH
PRESSURE RIDGE MOVING IN. EXPECT MOST LOCATIONS TO BE WELL BELOW
ZERO WITH THE COLDEST VALUES CONTINUING OVER THE INTERIOR WEST AND
CENTRAL (LOWS IN THE TEENS BELOW ZERO). WIND CHILL ADVISORY LOOKS
TO BE IN GOOD SHAPE AFTER THE MINOR ADJUSTMENTS AND WILL LEAVE THAT
AS IS. ONE OTHER ITEM TO NOTE IS A WEAK SHORTWAVE DIVING SOUTHEAST
ON THE BACK SIDE OF THE UPPER TROUGH THAT WILL MOVE THROUGH
NORTHERN MINNESOTA THIS EVENING AND INTO WISCONSIN OVERNIGHT. MAIN
INFLUENCE WILL BE SOME MID-HIGH CLOUDS...BUT INDICATIONS ARE THAT
MOST OF THOSE CLOUDS WILL STAY SOUTHWEST OF THE CWA TONIGHT BUT MAY
STREAM OVER DURING THE DAY TOMORROW. AREAS RIGHT ALONG THE WISCONSIN
BORDER WOULD HAVE THE BEST OPPORTUNITY FOR THESE MID CLOUDS...WHICH
COULD LEAD TO TEMPS WARMING SLIGHTLY TOWARDS DAYBREAK.
.LONG TERM...(THURSDAY NIGHT THROUGH WEDNESDAY)
ISSUED AT 430 PM EST WED DEC 11 2013
MODELS CONTINUE TO SUGGEST AN OVERALL COLD PATTERN THRU THE LONG
TERM PORTION OF THE FCST. HOWEVER...WITH CURRENT DEEP EXPANSIVE
POLAR VORTEX CENTERED AROUND HUDSON BAY WEAKENING AND RETREATING N
LATE THIS WEEK THRU AT LEAST THE MIDDLE OF NEXT WEEK...THE COLD WILL
EASE SOME. A VAST SUPPLY OF COLD AIR WILL REMAIN ACROSS CANADA...SO
ANY SHORTWAVE TRACKING ALONG IN THE RELAXING NW FLOW PATTERN WILL BE
ABLE TO BRING A SURGE OF COLDER AIR INTO THE UPPER LAKES. OVER THE
PAST SEVERAL DAYS...MEDIUM RANGE GUIDANCE HAS BEEN PROGRESSIVELY
SLOWER TO BRING WARMING INTO THE UPPER LAKES FOR THIS REASON. LATER
DOWN THE ROAD NEXT WEEK...THERE ARE SUGGESTIONS OF A TEMPORARY SHIFT
IN THE PATTERN TOWARD A DEEPENING TROF OVER THE WRN CONUS AND
DOWNSTREAM BUILDING RIDGE OVER THE SE CONUS/WRN ATLANTIC. THIS WILL
OFFER THE BEST CHANCE OF A WARMUP THAT WOULD OCCUR AROUND THE MIDDLE
NEXT WEEK. HOW MUCH WARMING OCCURS WILL DEPEND ON THE AMPLITUDE AND
LONGITUDE OF THE TROF/RIDGE PATTERN. WHATEVER HAPPENS...ANY WARMING
WILL ONLY BE BRIEF AS LONGER RANGE GUIDANCE POINTS TOWARD
REINTENSIFYING ARCTIC AIR ACROSS WRN/NRN CANADA DUMPING BACK INTO
THE AREA SOMETIME AROUND THE WEEKEND BEFORE CHRISTMAS OR EARLY
CHRISTMAS WEEK. OUTSIDE OF THE AREAS AFFECTED BY LES...DON`T EXPECT
MUCH MORE THAN SOME -SN AT TIMES DURING THE LONG TERM. POSSIBLE
BRIEF PATTERN CHANGE LATER NEXT WEEK COULD OFFER THE POTENTIAL FOR
SOMETHING MORE SUBSTANTIAL IN TERMS OF PCPN.
BEGINNING THU NIGHT...SHORTWAVE PASSING ACROSS NRN ONTARIO WILL SEND
A SFC TROF S THRU THE UPPER LAKES...CAUSING WINDS TO VEER NW OR N BY
FRI MORNING. AS A RESULT...ONGOING WRLY FLOW LES LATE THU AFTN WILL
SPREAD S...AFFECTING MOST IF NOT ALL OF NRN UPPER MI BY FRI MORNING.
ALTHOUGH THERE IS NOT MUCH IN THE WAY OF DEEP LAYER FORCING...PERIOD
OF DEEPER MOISTURE COMBINED WITH CONVERGENCE ALONG TROF SHOULD YIELD
A SHORT PERIOD OF MDT SNOW AND POSSIBLY BRIEF HVY SNOW AS TROF
SWEEPS S THU NIGHT AND FRI MORNING. BEHIND TROF...INVERSION SETTLES
TO AROUND 5-6KFT FRI. LARGER SCALE LOW-LEVEL FLOW ALSO BECOMES MORE
ANTICYCLONIC FRI. ON THE OTHER HAND...DIMINISHING BOUNDARY LAYER
WINDS MAY ALLOW FOR LOCALIZED CONVERGENCE. IN FACT...NAM INDICATES
WINDS VEERING TO ESE OFF ERN UPPER MI DURING THE DAY FRI...
RESULTING IN A ZONE OF ENHANCED CONVERGENCE EXTENDING ACROSS FAR SE
LAKE SUPERIOR TO THE MARQUETTE AREA. WILL BE SOMETHING TO MONITOR.
OTHERWISE...DGZ WILL BEGIN TO BECOME BETTER LOCATED WITHIN THE
CONVECTIVE LAYER AND UPWARD MOTION ZONE...LEADING TO HIGHER SNOW TO
WATER RATIOS. SO...SHOULD BE ABLE TO FLUFF UP SOME DECENT SNOW
ACCUMULATIONS FRI WHERE LES IS MOST PERISTENT (NCNTRL UPPER MI). OUT
W DURING THE DAY...WINDS MAY END UP VEERING ENOUGH TO PUSH MOST OF
THE LES OFFSHORE OF WRN UPPER MI...EXCEPT FOR THE KEWEENAW.
WINDS CONTINUE VEERING TO THE E THEN SE FRI NIGHT/SAT MORNING AS SFC
HIGH PRES CENTER PASSES JUST N OF LAKE SUPERIOR. LES THAT WILL BE
OCCURRING MAINLY INTO NCNTRL UPPER MI THU AFTN WILL THEN SLOWLY
SHIFT...CROSSING THE KEWEENAW PENINSULA FOR A TIME LATER FRI
NIGHT/SAT MORNING. DGZ WILL STILL BE WELL CENTERED IN THE CONVECTIVE
LAYER...SO A FEW INCHES OF FLUFFY SNOW ARE POSSIBLE. IF WINDS VEER
ENOUGH OVER NRN LAKE MI...SOME LIGHT LES MAY AFFECT PORTIONS OF
MENOMINEE COUNTY.
ATTENTION THEN TURNS TO NEXT CLIPPER SHORTWAVE DROPPING THRU THE
UPPER GREAT LAKES SAT NIGHT/SUN. -SN ASSOCIATED WITH FEATURE SHOULD
SPREAD INTO THE AREA SAT AFTN/EVENING...AND IT LOOKS LIKE THERE WILL
BE A QUICK PERIOD OF LAKE ENHANCEMENT OFF LAKE MI IN SOUTHERLY
FLOW...LEADING TO A POTENTIAL ADVY EVENT. A VERY BRIEF SHOT OF
ARCTIC AIR FOLLOWING SYSTEM WILL PROBABLY RESULT IN A SHORT DURATION
BOUT OF MDT TO POSSIBLY HVY LAKE ENHANCED SNOW FOR NORTHWEST AND
NORTHEAST UPPER MI LATE SAT NIGHT/EARLY SUNDAY AS WIND SHIFTS NW. AS
WINDS VEER AROUND TO THE N OR NE WITH SFC HIGH PRES PASSING ACROSS
NRN ONTARIO...LIGHTER LES WILL AGAIN SHIFT TO AFFECT MORE OF NRN
UPPER MI SUN AFTN/EVENING.
FCST IS MUCH MORE UNCERTAIN HEADING INTO MON/TUE AS MEDIUM RANGE
MODELS ARE HAVING TROUBLE WITH SEVERAL SHORTWAVES IN THE WNW FLOW.
GIVEN THE UNCERTAINTY FROM TODAYS MODEL RUNS AND PREVIOUS RUNS...A
SIMPLE CONSENSUS WILL BE UTILIZED MON/TUE. DEPENDING ON
STRENGTH/TRACK OF THE WAVES...THERE MAY BE A COUPLE OF PERIODS OF
WIDESPREAD -SN AS WELL AS LAKE ENHANCEMENT DEPENDING ON WIND
DIRECTION.
HIGH UNCERTAINTY CONTINUES WED AS ECMWF SHOWS THE POSSIBLE MID WEEK
WARMUP ALLUDED TO EARLIER...WHILE THE GFS DUMPS ARCTIC AIR BACK INTO
THE AREA. AT 00Z THU...850MB TEMPS RANGE FROM ROUGHLY AROUND -2C
WITH THE ECWMF TO -20C WITH THE GFS.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z THURSDAY EVENING)
ISSUED AT 622 PM EST WED DEC 11 2013
CMX...AS THE LLVL FLOW BACKS TOWARD SW TNGT WITH PASSAGE OF SFC HI
PRES TO THE S...EXPECT THE HEAVIER SHSN TO SHIFT TO THE N OF THIS
LOCATION. SO TREND TOWARD MVFR CONDITIONS OVERNGT STILL SEEMS ON
TRACK. BUT AS THE WINDS VEER AGAIN MORE TO THE WNW AND TURN GUSTY
ON THU...MORE SHSN/BLSN WL RETURN ALONG WITH IFR TO LIFR CONDITIONS.
FOR KSAW/KIWD...A WSW LLVL FLOW OF DRY UNMODIFIED ARCTIC AIR WL
RESULT IN VFR CONDITIONS THRU TNGT. AS THE FLOW VEERS MORE TO THE
WNW ON THU MRNG...SOME LOWER MVFR CIGS WL LIKELY RETURN TO IWD. BUT
THE DOWNSLOPE NATURE OF THIS FLOW INTO SAW SHOULD RESULT IN
PERSISTENT VFR CONDITIONS THERE.
&&
.MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 407 PM EST WED DEC 11 2013
WEST TO NORTHWEST WINDS OF 20-30KTS WILL WEAKEN SLIGHTLY TONIGHT AS
A HIGH PRESSURE RIDGE BRUSHES THE AREA. A WEAK TROUGH MOVING ACROSS
THE AREA ON THURSDAY WILL SHIFT WINDS TO MORE OF A NORTHWESTERLY
DIRECTION THURSDAY AFTERNOON AND TO THE NORTH THURSDAY NIGHT AS
ANOTHER HIGH PRESSURE RIDGE (THIS TIME FROM CENTRAL CANADA) NOSES
INTO WESTERN LAKE SUPERIOR. THIS RIDGE IS EXPECTED TO WEAKEN THE
WINDS BELOW 20KTS. DEPENDING ON THE STRENGTH OF A LOW MOVING ACROSS
LAKE SUPERIOR ON SATURDAY NIGHT AND SUNDAY AND THE STRENGTH OF THE
LOW MOVING UP THE EAST COAST...COULD SEE A INCREASE IN
NORTHWESTERLY WINDS ON SUNDAY TO 25-30KTS. THIS WILL BE SHORT LIVED
AS ANOTHER HIGH SLIDES INTO THE AREA FOR THE BEGINNING OF THE
UPCOMING WORK WEEK.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
WIND CHILL ADVISORY UNTIL NOON EST /11 AM CST/ THURSDAY FOR
MIZ002-004-005-009>013-084.
LAKE EFFECT SNOW ADVISORY UNTIL 7 PM EST THIS EVENING FOR MIZ085.
LAKE EFFECT SNOW ADVISORY UNTIL MIDNIGHT EST TONIGHT FOR MIZ002-
006.
LAKE EFFECT SNOW ADVISORY UNTIL 9 AM EST THURSDAY FOR MIZ001-003.
LAKE EFFECT SNOW WARNING UNTIL 7 AM EST THURSDAY FOR MIZ007.
LAKE SUPERIOR...
HEAVY FREEZING SPRAY WARNING UNTIL 6 AM EST /5 AM CST/ THURSDAY
FOR LSZ162-240>245-248>251-266.
HEAVY FREEZING SPRAY WARNING UNTIL 3 PM EST THURSDAY FOR
LSZ263>265.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...SRF
LONG TERM...ROLFSON
AVIATION...KC
MARINE...SRF
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
448 PM EST TUE DEC 10 2013
.SHORT TERM...(THIS EVENING THROUGH WEDNESDAY)
ISSUED AT 447 PM EST TUE DEC 10 2013
MAIN FCST CONCERN IN THE SHORT TERM REVOLVES AROUND LES TRENDS AS
REINFORCING ARCTIC AIR MASS PASSES ACROSS THE AREA.
WATER VAPOR IMAGERY AND RUC ANALYSIS SHOW AN EXPANSIVE POLAR VORTEX
CENTERED OVER HUDSON BAY. WITHIN THE CIRCULATION...ONE SHORTWAVE HAS
MOVED E OF UPPER MI/LAKE SUPERIOR. WAVE BROUGHT A PERIOD OF -SN WITH
VERY LITTLE ACCUMULATION ACROSS MAINLY SRN AND ERN UPPER MI EARLIER
TODAY. THE SMALL SNOWFLAKES WERE EXCELLENT VIS RESTRICTORS.
UPSTREAM...ANOTHER SHORTWAVE WAS SWINGING THRU SRN MANITOBA/ND/NRN
MN. TYPICAL FOR ARCTIC AIR MASSES...IN THE WAKE OF THE FIRST
SHORTWAVE...SKIES GENERALLY CLEARED OUT AWAY FROM LAKE EFFECT AREAS.
PER VIS SATELLITE IMAGERY...SFC TROF/WIND SHIFT ACROSS LAKE SUPERIOR
HAS LEAD TO A BAND OF HVY LES THAT HAS SETTLED S ACROSS THE KEWEENAW
TODAY. BAND IS A LITTLE MORE DISORGANIZED NOW...AND EXTENDS E ACROSS
ERN LAKE SUPERIOR PER SATELLITE/KMQT RADAR IMAGERY.
AS NEXT SHORTWAVE MOVES ACROSS THE AREA TONIGHT...MODELS ARE NOT
INDICATING MUCH IN THE WAY OF FORCING PER QVECTORS...PROBABLY DUE TO
CAA AT LOW-LEVELS. NONETHELESS...CONDITIONS ARE FAVORABLE FOR
MDT/HVY LES AS INVERSIONS ARE UP AROUND 8KFT. NEGATIVE FACTOR WILL
BE THE COLD AIR SUPPRESSING THE DGZ...MAINLY OVER THE W WHERE
SHORTER FETCH LEADS TO LESS LAKE MODERATION/WARMING OF THE
LOW-LEVELS. HAVE SOME CONCERN THAT SNOWFLAKES MAY END UP QUITE
SMALL...KEEPING ACCCUMULATIONS LOWER THAN FCST. ON THE OTHER
HAND...THE SMALL SNOWFLAKES CREATE MORE OF A DRIVING HAZARD DUE TO
THEIR EFFECTIVENESS AT REDUCING VIS. IN ANY EVENT...ADVYS REMAIN
UP FOR THE WRN COUNTIES. HEAVIEST SNOW SHOULD FOCUS ACROSS NRN
ONTANAGON COUNTY INTO CNTRL HOUGHTON COUNTY...WHERE LOW-LEVEL
CONVERGENCE WILL BE ESPECIALLY STRONG THRU THE EVENING.
OVER THE E...NOT ONLY DOES A LONGER FETCH AND HIGHER DGZ POINT
TOWARD MORE SIGNIFICANT ACCUMULATIONS...BUT THERE ARE INDICATIONS
FROM ALL HIGH RES MODEL GUIDANCE FOR ONE OR TWO AREAS OF STRONGLY
FOCUSED CONVERGENCE OWING TO LAND BREEZES OFF ONTARIO AND NCNTRL
UPPER MI. EXACTLY WHERE THE CONVERGENCE ZONES SET UP AND WHETHER
THEY REMAIN STATIONARY OR MEANDER WILL CONTROL HOW MUCH SNOW FALLS.
PERUSAL OF A NUMBER OF HIGH RES MODELS SHOW WATER EQUIVALENT PCPN
TOTALS ANYWHERE FROM 1.5 TO 3.5 INCHES AIMING TOWARD WHITEFISH PT
VCNTY BY WED EVENING. IF SNOW RATIOS END UP AROUND 20 TO 1...YOU END
UP WITH A RIDICULOUS POTENTIAL SNOW ACCUMULATION. HOW THE EXPECTED
BAND OR BANDS SETUP TONIGHT WILL SET THE STAGE FOR WHETHER OR NOT
THE POTENTIAL SNOW ACCUMULATION IS REALIZED SOMEWHERE OVER NE UPPER
MI. OTHERWISE...OVERALL MODEL TREND SUGGESTS A LITTLE MORE NORTHERLY
COMPONENT TO THE WIND...SO ADVY WAS EXPANDED TO NRN SCHOOLCRAFT
COUNTY AND HEAVIER SNOW AMOUNTS WERE SPREAD A LITTLE FARTHER W IN
ALGER COUNTY...THOUGH HEAVIEST SNOW BANDS SHOULD STILL END UP E OF
MUNISING.
ONLY OTHER ITEM OF NOTE TONIGHT WAS INCLUSION OF LOW WIND CHILLS IN
HEADLINE PRODUCTS OVER WRN UPPER MI...INCLUDING WIND CHILL ADVY FOR
IRON COUNTY WHICH WAS NOT UNDER HEADLINE INVOLVING SNOW.
ON WED...LES WILL TREND LIGHTER OVER THE W AS INVERSIONS FALL A BIT.
LES SHOULD REMAIN QUITE HEAVY OVER THE E...ESPECIALLY DURING THE
MORNING WHEN CONVERGENCE REMAINS STRONG.
.LONG TERM...(WEDNESDAY NIGHT THROUGH TUESDAY)
ISSUED AT 410 PM EST TUE DEC 10 2013
LOOK FOR A SERIES OF SYSTEMS TO SLIDE IN ON THE NW FLOW
ALOFT...KEEPING SNOW IN THE FCST FOR MUCH OF THE PERIOD. IT WILL BE
A PERIOD OF ALMOST CONTINUOUS SFC TROUGHS OVER CENTRAL AND EASTERN
UPPER MI. THE BUFKIT TIME HEIGHT/OVERVIEW DATA FROM THE GFS AT CMX
LOOKS IMPRESSIVE. ALTHOUGH SNOW AMOUNTS ARE RELATIVELY
MINIMAL...THERE IS NEARLY CONSTANT SNOW FCST THROUGH 06Z MONDAY.
THE PERSISTENT 500MB TROUGH OVER EASTERN CANADA AND THE EAST HALF OF
THE UNITED STATES WILL STILL BE IN PLACE WEDNESDAY NIGHT. EVEN OVER
THE W HALF OF THE NATION THE SIZABLE RIDGE EXTENDING UP THROUGH THE
CASCADES WILL BE UNDERMINED BY CLOSED LOW SPINNING ACROSS S CA
WEDNESDAY NIGHT THROUGH THURSDAY. EXPECT NW FLOW ALOFT THROUGH THE
END OF THE WORK WEEK. THE MODELS SPREAD FOR TEMPERATURES FRIDAY
AFTERNOON ARE ALL OVER THE PLACE...RANGING FROM AROUND 6 TO 23 NEAR
THE WI BORDER. WENT WITH A MIDDLE OF THE ROAD FCST FOR NOW WITH
HIGHS IN THE TEENS CWA WIDE...AND WILL FINE-TUNE IT AS THE TIME
NEARS.
BY 00Z SATURDAY THE MAIN LOW WILL HAVE MOVED FROM HUDSON BAY TO
CENTRAL QUEBEC...SLOWLY MARKING THE END TO ITS DOMINANCE. WHILE SOME
IMPROVEMENT IN THE FRIGGED TEMPERATURES OF LATE FRIDAY INTO
SATURDAY...WE WILL STILL END UP WELL BELOW THE NORMAL HIGH TEMPS FOR
THIS TIME OF YEAR...WHICH MAY TYPICALLY RISE INTO THE MID TO UPPER
20S.
THE NEXT QUICK MOVING WAVE IN THE 500MB NW FLOW OVER N SASKATCHEWAN
AND MANITOBA AT 06Z SATURDAY WILL PUSH ACROSS THE UPPER GREAT LAKES
LATE SATURDAY NIGHT THROUGH SUNDAY.
EXPECT BRIEF RIDGING ALOFT SUNDAY NIGHT INTO MONDAY TO BECOME
SUPPRESSED AHEAD OF THE NEXT TROUGH NEARING FROM THE NORTHWEST. THE
BEST CHANCE FOR SHORT LIVED CWA-WIDE HIGH PRESSURE AT THE SFC WILL
BE SUNDAY NIGHT. THIS WILL BE THE ONLY PERIOD WITH SLIGHT CHANCE
POPS OR LESS ACROSS THE AREA. THE TROUGH TO THE NORTHWEST WILL
LIKELY SWING ACROSS THE UPPER GREAT LAKES MONDAY...AND LINGER
THROUGH TUESDAY...AS LES PICKS UP AGAIN ACROSS THE KEWEENAW
PENINSULA. THE GFS AND ECMWF HAD VERY SIMILAR TIMING ON THE SFC
LOW...SET UP ACROSS CENTRAL LAKE SUPERIOR AND EASTERN ONTARIO AT 18Z
TUESDAY.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z WEDNESDAY AFTERNOON)
ISSUED AT 1226 PM EST TUE DEC 10 2013
KIWD...EXPECT VFR CONDITIONS TO PREDOMINATE THRU THIS AFTN BEFORE A
LO PRES TROF CROSSES THE AREA THIS EVNG AND BRINGS SOME -SHSN/MVFR
CONDITIONS THAT WL PERSIST FOR THE REST OF THE FCST PERIOD.
KCMX...EXPECT IFR TO VLIFR CONDITIONS FOR THE FIRST FEW HRS OF THE
FCST PERIOD AS A HEAVIER SN BAND ALONG A LO PRES TROF CROSSES THE
KEWEENAW PENINSULA. WITH A WSHFT TO THE WNW AND GUSTY WINDS THRU THE
REST OF THE FCST PERIOD BEHIND THIS TROF...THE COMBINATION OF -SHSN/
BLSN SHOULD RESULT IN PREDOMINANT IFR/LIFR VSBYS.
KSAW...VFR CONDITIONS WILL CONTINUE THRU THE FORECAST PERIOD.
ALTHOUGH A LO PRES TROF WL CROSS THE AREA THIS EVNG...DOWNSLOPE
NATURE OF THE W WIND AND RELATIVE DRYNESS OF THE AIRMASS SHOULD
MAINTAIN THE VFR WX AT THIS SITE.
&&
.MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 410 PM EST TUE DEC 10 2013
FREEZING SPRAY AND GALES TO 35-40KTS WILL BE THE MAIN
CONCERNS...COMING TO AN END WEDNESDAY NIGHT. HIGH PRESSURE OVER W
CANADA WILL DRIFT SE THROUGH THURSDAY NIGHT. EXPECT A TROUGH TO
LINGER OVER THE UPPER GREAT LAKES DURING THE SAME TIME PERIOD.
ANOTHER HIGH CENTERED OVER CENTRAL CANADA WILL THEN SLIDE ACROSS
ONTARIO ON FRIDAY...AND INTO QUEBEC ON SATURDAY. ALSO FRIDAY INTO
SATURDAY...A LOW WILL ORGANIZE ACROSS THE MID MISSISSIPPI VALLEY.
THE LOW WILL SHIFT INTO THE NE STATES SUNDAY...WITH A TROUGH
LINGERING OVER THE UPPER GREAT LAKES...AS HIGH PRESSURE SLIDES
ACROSS MANITOBA.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
LAKE EFFECT SNOW ADVISORY UNTIL 5 PM EST WEDNESDAY FOR MIZ004-
084.
LAKE EFFECT SNOW ADVISORY FROM 1 AM TO 7 PM EST WEDNESDAY FOR
MIZ085.
LAKE EFFECT SNOW ADVISORY UNTIL MIDNIGHT EST WEDNESDAY NIGHT FOR
MIZ006.
LAKE EFFECT SNOW ADVISORY UNTIL MIDNIGHT EST WEDNESDAY NIGHT FOR
MIZ002-003.
LAKE EFFECT SNOW ADVISORY UNTIL 7 AM EST WEDNESDAY FOR MIZ001.
LAKE EFFECT SNOW ADVISORY UNTIL 11 AM CST WEDNESDAY FOR MIZ009.
LAKE EFFECT SNOW WARNING UNTIL 7 AM EST THURSDAY FOR MIZ007.
WIND CHILL ADVISORY FROM MIDNIGHT TONIGHT TO 11 AM CST WEDNESDAY
FOR MIZ010.
LAKE SUPERIOR...
HEAVY FREEZING SPRAY WARNING UNTIL 6 PM EST WEDNESDAY FOR LSZ266.
GALE WARNING UNTIL MIDNIGHT EST TONIGHT FOR LSZ249-250-266.
HEAVY FREEZING SPRAY WARNING UNTIL 6 AM EST THURSDAY FOR
LSZ242>245-248>251-263>265.
HEAVY FREEZING SPRAY WARNING UNTIL 6 AM EST /5 AM CST/ THURSDAY
FOR LSZ162-240-241.
LAKE MICHIGAN...
HEAVY FREEZING SPRAY WARNING UNTIL 6 AM EST WEDNESDAY FOR LMZ221-
248-250.
&&
$$
SHORT TERM...ROLFSON
LONG TERM...KF
AVIATION...KC
MARINE...KF
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
411 PM EST TUE DEC 10 2013
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 557 AM EST TUE DEC 10 2013
MAIN CONCERN IN SHORT TERM IS ANOTHER BOUT OF MODERATE TO HEAVY LES
EXPECTED TO BEGIN LATE THIS MORNING WEST AND TOWARD EVENING FAR
EAST. EXPECT THE PROLONGED LES EVENT TO CONTINUE THROUGH MUCH OF WED
FOR THE WEST AND THROUGH WED NIGHT FOR FAR ERN SHORELINE
AREAS.
WV IMAGERY AND RUC ANALYSIS INDICATED A BROAD TROUGH ACROSS NOAM.
THERE ARE TWO MAIN SHORTWAVES OF NOTE WITHIN THIS BROAD TROUGH. ONE
SHORTWAVE WAS MOVING EAST ACROSS MN WHILE A SECOND SHORTWAVE WAS
FARTHER UPSTREAM DIVING DOWN FROM SASKATCHEWAN. A SFC HIGH PRESSURE
RIDGE WAS STILL RESULTING IN GENERALLY CLEAR SKIES ACROSS MUCH OF
UPPER MI EARLY THIS MORNING. THE CLEAR SKIES HAVE ALLOWED TEMPS TO
DROP INTO SINGLE DIGITS BLO ZERO ACROSS MUCH OF THE AREA WITH A FEW
DOUBLE DIGIT BLO ZERO READINGS ALONG THE WI BDR. ASSOC FORCING AND
WEAK WAA AHEAD OF MN SHORTWAVE HAS BROUGHT SOME CLOUD COVER INTO
AREAS ALONG THE WI BDR. EXPECT THESE CLOUDS ALONG WITH SOME LIGHT
SNOW/FLURRIES TO SPREAD EAST ACROSS THE SRN TIER OF THE FCST AREA
THE REST OF THE MORNING BRINGING TEMPS UP A FEW DEGREES TOWARD
SUNRISE. WIND CHILLS HAVE HOVERED JUST BLO ADVISORY CRITERIA EARLY
THIS MORNING...GENERALLY FROM 15 TO 25 BELOW. WINDS BACKING SW AHEAD
OF APPROACHING TROUGH FROM MN HAVE ALSO PUSHED LES BANDS FM KEWEENAW
OUT OVER LAKE SUPERIOR EARLY THIS MORNING.
TODAY AND TONIGHT...THE MODERATE TO STRONG Q-VECT CONV ASSOC WITH MN
SHORTWAVE WILL LIKELY BRING A LIGHT DUSTING OF SNOW ACCUMULATION
(LESS THAN HALF AN INCH) TO MAINLY THE SRN PORTION OF THE CWA THIS
MORNING. THE SECOND SHORTWAVE MOVING DOWN FROM SASKATCHEWAN WILL
SPREAD MODERATE 700-300 MB QVECTOR CONV ACROSS LAKE SUPERIOR WHICH
WILL PROVIDE FOR A PERIOD OF ENHANCEMENT TO LES BANDS SETTING UP IN
STRONGLY CONVERGENT WRLY FLOW OVER THE MIDDLE OF THE LAKE.
WINDS VEERING IN THE WAKE OF THE SHRTWV SHOULD BRING ANOTHER STRONG
AREA OF LOW LEVEL CONV INTO NW UPPER MI AS THE SFC TROUGH MOVES
THROUGH AROUND 18Z. EXPECT ANOTHER PERIOD OF MODERATE TO HEAVY LES
OVER WRN UPR MI BEGINNING LATE THIS MORNING OVER KEWEENAW/NRN
HOUGHTON AND ONTONAGON COUNTIES AND EARLY THIS AFTERNOON FOR SRN
HOUGHTON/BARAGA AND GOGEBIC COUNTIES. WOULD NOT BE SURPRISED TO SEE
BRIEF 1-2 INCH SNOWFALL RATES AS DOMINANT LES BAND LIKELY TRAVERSES
THE AREA. STRONGLY CONVERGENT WNW FLOW WILL CONTINUE
TONIGHT...ESPECIALLY INTO HOUGHTON...ONTONAGON AND BARAGA COUNTIES
AS POTENTIAL FOR MODERATE TO HEAVY SNOW BAND COULD BRING ADDITIONAL
SIGNIFICANT ACCUMULATION. ALTHOUGH DGZ DOES COMPRESS INTO THE LOWEST
2KFT OF ATMOSPHERE UNDER FAIRLY STRONG CAA (8H TEMPS LOWER TO AROUND
-25C BY WED MORNING)...THERE IS STILL SOME MODEL OMEGA NOTED WITH
THIS LAYER. STRONG WINDS HOWEVER COULD RESULT IN FRACTURING OF
DENDRITES LEADING TO LOWER SLR THAN OTHERWISE EXPECTED. FOR NOW WILL
KEEP WITH THE NEAR 20/1 SLR FOR FIGURING SNOW ACCUMS. WITH THE
POTENTIAL FOR A PROLONGED LES EVENT IN STRONGLY CONVERGENT WNW
FLOW...HAVE DECIDED TO ISSUE LES ADVISORIES FOR THE 4 WRN COUNTIES
AND WILL ALSO INCLUDE BARAGA COUNTY. SOME LOCATIONS ESPECIALLY
FROM TWIN LAKES THROUGH PELKIE TO ROCKLAND WILL LIKELY EXCEED A FOOT
OF TOTAL SNOWFALL FROM LATE TODAY THROUGH WEDNESDAY.
WINDS VEERING OVER THE ERN LAKE THIS AFERNOON WILL BEGIN TO PUSH A
DOMINANT LES BAND ONSHORE OVER THE FAR ERN CWA THIS EVENING. STRONG
CONVERGENCE SETTING UP OVER THIS AREA TONIGHT INTO WEDNESDAY FROM
LAND BREEZES OFF ONTARIO AND UPPER MI WILL ALSO LEAD TO PROLONGED
PERIOD OF HEAVY LES AS INVERSIONS FROM 8-10 KFT ARE EXPECTED THROUGH
MUCH OF PD ALONG WITH FAIRLY FAVORABLE SNOW GROWTH. TOTAL SNOW
ACCUMS FROM TONIGHT THROUGH WED NIGHT COULD EXCEED 18 INCHES FROM
GRAND MARAIS TO TWO HEART ALONG THE LAKE SUPERIOR SHORE. AS A
RESULT...HAVE ISSUED A LONG TERM LES ADVISORY FOR ERN ALGER COUNTY
AND A LES WARNING FOR LUCE COUNTY.
WINDS CHILLS TONIGHT COULD APPROACH ADVISORY CRITERIA ESPECIALLY
ALONG THE WI BDR INTERIOR WEST AS ACTUAL TEMPS DROP NEAR
-10F.
.LONG TERM...(WEDNESDAY NIGHT THROUGH TUESDAY)
ISSUED AT 410 PM EST TUE DEC 10 2013
LOOK FOR A SERIES OF SYSTEMS TO SLIDE IN ON THE NW FLOW
ALOFT...KEEPING SNOW IN THE FCST FOR MUCH OF THE PERIOD. IT WILL BE
A PERIOD OF ALMOST CONTINUOUS SFC TROUGHS OVER CENTRAL AND EASTERN
UPPER MI. THE BUFKIT TIME HEIGHT/OVERVIEW DATA FROM THE GFS AT CMX
LOOKS IMPRESSIVE. ALTHOUGH SNOW AMOUNTS ARE RELATIVELY
MINIMAL...THERE IS NEARLY CONSTANT SNOW FCST THROUGH 06Z MONDAY.
THE PERSISTENT 500MB TROUGH OVER EASTERN CANADA AND THE EAST HALF OF
THE UNITED STATES WILL STILL BE IN PLACE WEDNESDAY NIGHT. EVEN OVER
THE W HALF OF THE NATION THE SIZABLE RIDGE EXTENDING UP THROUGH THE
CASCADES WILL BE UNDERMINED BY CLOSED LOW SPINNING ACROSS S CA
WEDNESDAY NIGHT THROUGH THURSDAY. EXPECT NW FLOW ALOFT THROUGH THE
END OF THE WORK WEEK. THE MODELS SPREAD FOR TEMPERATURES FRIDAY
AFTERNOON ARE ALL OVER THE PLACE...RANGING FROM AROUND 6 TO 23 NEAR
THE WI BORDER. WENT WITH A MIDDLE OF THE ROAD FCST FOR NOW WITH
HIGHS IN THE TEENS CWA WIDE...AND WILL FINE-TUNE IT AS THE TIME
NEARS.
BY 00Z SATURDAY THE MAIN LOW WILL HAVE MOVED FROM HUDSON BAY TO
CENTRAL QUEBEC...SLOWLY MARKING THE END TO ITS DOMINANCE. WHILE SOME
IMPROVEMENT IN THE FRIGGED TEMPERATURES OF LATE FRIDAY INTO
SATURDAY...WE WILL STILL END UP WELL BELOW THE NORMAL HIGH TEMPS FOR
THIS TIME OF YEAR...WHICH MAY TYPICALLY RISE INTO THE MID TO UPPER
20S.
THE NEXT QUICK MOVING WAVE IN THE 500MB NW FLOW OVER N SASKATCHEWAN
AND MANITOBA AT 06Z SATURDAY WILL PUSH ACROSS THE UPPER GREAT LAKES
LATE SATURDAY NIGHT THROUGH SUNDAY.
EXPECT BRIEF RIDGING ALOFT SUNDAY NIGHT INTO MONDAY TO BECOME
SUPPRESSED AHEAD OF THE NEXT TROUGH NEARING FROM THE NORTHWEST. THE
BEST CHANCE FOR SHORT LIVED CWA-WIDE HIGH PRESSURE AT THE SFC WILL
BE SUNDAY NIGHT. THIS WILL BE THE ONLY PERIOD WITH SLIGHT CHANCE
POPS OR LESS ACROSS THE AREA. THE TROUGH TO THE NORTHWEST WILL
LIKELY SWING ACROSS THE UPPER GREAT LAKES MONDAY...AND LINGER
THROUGH TUESDAY...AS LES PICKS UP AGAIN ACROSS THE KEWEENAW
PENINSULA. THE GFS AND ECMWF HAD VERY SIMILAR TIMING ON THE SFC
LOW...SET UP ACROSS CENTRAL LAKE SUPERIOR AND EASTERN ONTARIO AT 18Z
TUESDAY.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z WEDNESDAY AFTERNOON)
ISSUED AT 1226 PM EST TUE DEC 10 2013
KIWD...EXPECT VFR CONDITIONS TO PREDOMINATE THRU THIS AFTN BEFORE A
LO PRES TROF CROSSES THE AREA THIS EVNG AND BRINGS SOME -SHSN/MVFR
CONDITIONS THAT WL PERSIST FOR THE REST OF THE FCST PERIOD.
KCMX...EXPECT IFR TO VLIFR CONDITIONS FOR THE FIRST FEW HRS OF THE
FCST PERIOD AS A HEAVIER SN BAND ALONG A LO PRES TROF CROSSES THE
KEWEENAW PENINSULA. WITH A WSHFT TO THE WNW AND GUSTY WINDS THRU THE
REST OF THE FCST PERIOD BEHIND THIS TROF...THE COMBINATION OF -SHSN/
BLSN SHOULD RESULT IN PREDOMINANT IFR/LIFR VSBYS.
KSAW...VFR CONDITIONS WILL CONTINUE THRU THE FORECAST PERIOD.
ALTHOUGH A LO PRES TROF WL CROSS THE AREA THIS EVNG...DOWNSLOPE
NATURE OF THE W WIND AND RELATIVE DRYNESS OF THE AIRMASS SHOULD
MAINTAIN THE VFR WX AT THIS SITE.
&&
.MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 410 PM EST TUE DEC 10 2013
FREEZING SPRAY AND GALES TO 35-40KTS WILL BE THE MAIN
CONCERNS...COMING TO AN END WEDNESDAY NIGHT. HIGH PRESSURE OVER W
CANADA WILL DRIFT SE THROUGH THURSDAY NIGHT. EXPECT A TROUGH TO
LINGER OVER THE UPPER GREAT LAKES DURING THE SAME TIME PERIOD.
ANOTHER HIGH CENTERED OVER CENTRAL CANADA WILL THEN SLIDE ACROSS
ONTARIO ON FRIDAY...AND INTO QUEBEC ON SATURDAY. ALSO FRIDAY INTO
SATURDAY...A LOW WILL ORGANIZE ACROSS THE MID MISSISSIPPI VALLEY.
THE LOW WILL SHIFT INTO THE NE STATES SUNDAY...WITH A TROUGH
LINGERING OVER THE UPPER GREAT LAKES...AS HIGH PRESSURE SLIDES
ACROSS MANITOBA.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
LAKE EFFECT SNOW ADVISORY UNTIL 5 PM EST WEDNESDAY FOR MIZ004-
084.
LAKE EFFECT SNOW ADVISORY FROM 1 AM TO 7 PM EST WEDNESDAY FOR
MIZ085.
LAKE EFFECT SNOW ADVISORY UNTIL MIDNIGHT EST WEDNESDAY NIGHT FOR
MIZ006.
LAKE EFFECT SNOW ADVISORY UNTIL MIDNIGHT EST WEDNESDAY NIGHT FOR
MIZ002-003.
LAKE EFFECT SNOW ADVISORY UNTIL 7 AM EST WEDNESDAY FOR MIZ001.
LAKE EFFECT SNOW ADVISORY UNTIL 11 AM CST WEDNESDAY FOR MIZ009.
LAKE EFFECT SNOW WARNING UNTIL 7 AM EST THURSDAY FOR MIZ007.
WIND CHILL ADVISORY FROM MIDNIGHT TONIGHT TO 11 AM CST WEDNESDAY
FOR MIZ010.
LAKE SUPERIOR...
HEAVY FREEZING SPRAY WARNING UNTIL 6 PM EST WEDNESDAY FOR LSZ266.
GALE WARNING UNTIL MIDNIGHT EST TONIGHT FOR LSZ249-250-266.
HEAVY FREEZING SPRAY WARNING UNTIL 6 AM EST THURSDAY FOR
LSZ242>245-248>251-263>265.
HEAVY FREEZING SPRAY WARNING UNTIL 6 AM EST /5 AM CST/ THURSDAY
FOR LSZ162-240-241.
LAKE MICHIGAN...
HEAVY FREEZING SPRAY WARNING UNTIL 6 AM EST WEDNESDAY FOR LMZ221-
248-250.
&&
$$
SHORT TERM...VOSS
LONG TERM...KF
AVIATION...KC
MARINE...KF
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
1228 PM EST TUE DEC 10 2013
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 557 AM EST TUE DEC 10 2013
MAIN CONCERN IN SHORT TERM IS ANOTHER BOUT OF MODERATE TO HEAVY LES
EXPECTED TO BEGIN LATE THIS MORNING WEST AND TOWARD EVENING FAR
EAST. EXPECT THE PROLONGED LES EVENT TO CONTINUE THROUGH MUCH OF WED
FOR THE WEST AND THROUGH WED NIGHT FOR FAR ERN SHORELINE
AREAS.
WV IMAGERY AND RUC ANALYSIS INDICATED A BROAD TROUGH ACROSS NOAM.
THERE ARE TWO MAIN SHORTWAVES OF NOTE WITHIN THIS BROAD TROUGH. ONE
SHORTWAVE WAS MOVING EAST ACROSS MN WHILE A SECOND SHORTWAVE WAS
FARTHER UPSTREAM DIVING DOWN FROM SASKATCHEWAN. A SFC HIGH PRESSURE
RIDGE WAS STILL RESULTING IN GENERALLY CLEAR SKIES ACROSS MUCH OF
UPPER MI EARLY THIS MORNING. THE CLEAR SKIES HAVE ALLOWED TEMPS TO
DROP INTO SINGLE DIGITS BLO ZERO ACROSS MUCH OF THE AREA WITH A FEW
DOUBLE DIGIT BLO ZERO READINGS ALONG THE WI BDR. ASSOC FORCING AND
WEAK WAA AHEAD OF MN SHORTWAVE HAS BROUGHT SOME CLOUD COVER INTO
AREAS ALONG THE WI BDR. EXPECT THESE CLOUDS ALONG WITH SOME LIGHT
SNOW/FLURRIES TO SPREAD EAST ACROSS THE SRN TIER OF THE FCST AREA
THE REST OF THE MORNING BRINGING TEMPS UP A FEW DEGREES TOWARD
SUNRISE. WIND CHILLS HAVE HOVERED JUST BLO ADVISORY CRITERIA EARLY
THIS MORNING...GENERALLY FROM 15 TO 25 BELOW. WINDS BACKING SW AHEAD
OF APPROACHING TROUGH FROM MN HAVE ALSO PUSHED LES BANDS FM KEWEENAW
OUT OVER LAKE SUPERIOR EARLY THIS MORNING.
TODAY AND TONIGHT...THE MODERATE TO STRONG Q-VECT CONV ASSOC WITH MN
SHORTWAVE WILL LIKELY BRING A LIGHT DUSTING OF SNOW ACCUMULATION
(LESS THAN HALF AN INCH) TO MAINLY THE SRN PORTION OF THE CWA THIS
MORNING. THE SECOND SHORTWAVE MOVING DOWN FROM SASKATCHEWAN WILL
SPREAD MODERATE 700-300 MB QVECTOR CONV ACROSS LAKE SUPERIOR WHICH
WILL PROVIDE FOR A PERIOD OF ENHANCEMENT TO LES BANDS SETTING UP IN
STRONGLY CONVERGENT WRLY FLOW OVER THE MIDDLE OF THE LAKE.
WINDS VEERING IN THE WAKE OF THE SHRTWV SHOULD BRING ANOTHER STRONG
AREA OF LOW LEVEL CONV INTO NW UPPER MI AS THE SFC TROUGH MOVES
THROUGH AROUND 18Z. EXPECT ANOTHER PERIOD OF MODERATE TO HEAVY LES
OVER WRN UPR MI BEGINNING LATE THIS MORNING OVER KEWEENAW/NRN
HOUGHTON AND ONTONAGON COUNTIES AND EARLY THIS AFTERNOON FOR SRN
HOUGHTON/BARAGA AND GOGEBIC COUNTIES. WOULD NOT BE SURPRISED TO SEE
BRIEF 1-2 INCH SNOWFALL RATES AS DOMINANT LES BAND LIKELY TRAVERSES
THE AREA. STRONGLY CONVERGENT WNW FLOW WILL CONTINUE
TONIGHT...ESPECIALLY INTO HOUGHTON...ONTONAGON AND BARAGA COUNTIES
AS POTENTIAL FOR MODERATE TO HEAVY SNOW BAND COULD BRING ADDITIONAL
SIGNIFICANT ACCUMULATION. ALTHOUGH DGZ DOES COMPRESS INTO THE LOWEST
2KFT OF ATMOSPHERE UNDER FAIRLY STRONG CAA (8H TEMPS LOWER TO AROUND
-25C BY WED MORNING)...THERE IS STILL SOME MODEL OMEGA NOTED WITH
THIS LAYER. STRONG WINDS HOWEVER COULD RESULT IN FRACTURING OF
DENDRITES LEADING TO LOWER SLR THAN OTHERWISE EXPECTED. FOR NOW WILL
KEEP WITH THE NEAR 20/1 SLR FOR FIGURING SNOW ACCUMS. WITH THE
POTENTIAL FOR A PROLONGED LES EVENT IN STRONGLY CONVERGENT WNW
FLOW...HAVE DECIDED TO ISSUE LES ADVISORIES FOR THE 4 WRN COUNTIES
AND WILL ALSO INCLUDE BARAGA COUNTY. SOME LOCATIONS ESPECIALLY
FROM TWIN LAKES THROUGH PELKIE TO ROCKLAND WILL LIKELY EXCEED A FOOT
OF TOTAL SNOWFALL FROM LATE TODAY THROUGH WEDNESDAY.
WINDS VEERING OVER THE ERN LAKE THIS AFERNOON WILL BEGIN TO PUSH A
DOMINANT LES BAND ONSHORE OVER THE FAR ERN CWA THIS EVENING. STRONG
CONVERGENCE SETTING UP OVER THIS AREA TONIGHT INTO WEDNESDAY FROM
LAND BREEZES OFF ONTARIO AND UPPER MI WILL ALSO LEAD TO PROLONGED
PERIOD OF HEAVY LES AS INVERSIONS FROM 8-10 KFT ARE EXPECTED THROUGH
MUCH OF PD ALONG WITH FAIRLY FAVORABLE SNOW GROWTH. TOTAL SNOW
ACCUMS FROM TONIGHT THROUGH WED NIGHT COULD EXCEED 18 INCHES FROM
GRAND MARAIS TO TWO HEART ALONG THE LAKE SUPERIOR SHORE. AS A
RESULT...HAVE ISSUED A LONG TERM LES ADVISORY FOR ERN ALGER COUNTY
AND A LES WARNING FOR LUCE COUNTY.
WINDS CHILLS TONIGHT COULD APPROACH ADVISORY CRITERIA ESPECIALLY
ALONG THE WI BDR INTERIOR WEST AS ACTUAL TEMPS DROP NEAR
-10F.
.LONG TERM...(WEDNESDAY THROUGH MONDAY)
ISSUED AT 534 AM EST TUE DEC 10 2013
CONTINUED COLD WITH PERSISTENT LAKE EFFECT SNOWS THROUGH
THURSDAY...THEN A TREND TOWARD SLIGHTLY WARMER TEMPERATURES BY THE
WEEKEND.
WEDNESDAY AND WEDNESDAY NIGHT...DEEP TROUGHING OVER EASTERN CANADA
WILL CONTINUE TO SEND MULTIPLE WAVES ACROSS THE UPPER GREAT
LAKES...WITH THE FIRST TROUGH AXIS CROSSING UPPER MI AT THE START
OF THE PERIOD. MODERATE TO HEAVY LES WILL BE ONGOING FOR WNW SNOW
BELTS...ESPECIALLY ACROSS NORTHERN LUCE AND FAR EASTERN ALGER
COUNTIES WHERE A SFC LAKE-ENHANCED TROUGH WILL BE ASSISTING WITH
ABUNDANT LOW-LEVEL CONVERGENCE. AFTER COORDINATION WITH THE SHORT
TERM FORECASTER AND WFO GAYLORD...A LAKE EFFECT SNOW WARNING WAS
ISSUED FOR LUCE COUNTY THIS EVENING THROUGH WEDNESDAY NIGHT. SEE THE
SHORT TERM DISCUSSION FOR FURTHER DETAILS ABOUT THE LES POTENTIAL
TONIGHT.
THE MAIN SFC TROUGH OVER LAKE SUPERIOR TONIGHT WILL BE PUSHING
SOUTHWARD ACROSS THE EASTERN CWA WEDNESDAY MORNING WHILE A WEAK
LAKE-ENHANCED TROUGH REMAINS OVER EASTERN LAKE SUPERIOR. THE VEERING
OF WINDS BEHIND THE MAIN TROUGH WILL BE ENOUGH TO DISRUPT DOMINATE
LES BANDS AND SHOVE THEM FARTHER SOUTHWARD INTO LUCE AND ALGER
COUNTIES. A QUICK BURST OF SNOW CAN BE EXPECTED FOR MOST LOCATIONS
AS THIS OCCURS. MEANWHILE...MULTI-BAND LES WILL PERSIST ACROSS
WESTERN UPPER MI FOR WNW SNOW BELTS AS -25C H8 AIR CONTINUES TO
FILTER INTO THE CWA. THERE ARE SIGNS THAT A MORE DOMINATE BAND MAY
EXIST INTO CENTRAL HOUGHTON COUNTY AND FAR NORTHERN ONTONAGON
COUNTY DURING THE AFTERNOON...SO AMOUNTS SHOULD BE HIGHEST THERE.
INVERSION HEIGHTS FALLING TO BELOW 5KFT FOR THE ENTIRE AREA AND
BACKING WINDS AHEAD OF AN APPROACHING SFC RIDGE WILL REDUCE LES
INTENSITY GREATLY WEDNESDAY EVENING.
A VERY COLD WEDNESDAY NIGHT COULD BE IN STORE...THOUGH TEMPERATURES
WILL BE HINGING ON THE GRADIENT FLOW TO LAX BEFORE MID-LEVEL CLOUDS
BRUSH THE AREA LATE IN THE NIGHT. A SFC RIDGE AXIS WILL BE DRIFTING
ACROSS NORTHERN WI THROUGHOUT THE NIGHT...THOUGH CONTINUED MODEL
SUPPORT OF A LAKE-ENHANCED TROUGH OVER EASTERN LAKE SUPERIOR WILL
INCREASE THE PRESSURE GRADIENT ACROSS THE WESTERN CWA.
HOWEVER...SOUNDING FORECASTS FROM THE INTERIOR WEST SHOW DECENT
ENOUGH SFC DECOUPLING TO ALLOW FOR APPRECIABLE RADIATIONAL COOLING.
MID-LEVEL CLOUDS WILL BE ON THE RISE ACROSS MUCH OF WI LATE IN THE
NIGHT AS A VERY WEAK CLIPPER SYSTEM TRACKS SE TOWARD THE AREA. THIS
TRACK IS FARTHER SOUTH THAN PREVIOUSLY ADVERTISED BY THE
MODELS...WHICH SHOULD LIMIT THE OVERALL IMPACT OF CLOUD-COVER ON
TEMPS ACROSS THE CWA. WITH ALL THAT SAID...JUXTAPOSITION OF BEST
COOLING FACTORS SHOULD BE ACROSS THE INTERIOR CWA WHERE TEMPS COULD
BOTTOM OUT BELOW -20F. WITH GRADIENT FLOW OF 5-10 MPH...WIND CHILLS
WILL APPROACH -35F. ADVISORY/WARNING DECISIONS WILL BE TRICKY WITH
WINDS EXPECTED BELOW THE 10 MPH CRITERIA. HOWEVER...IF THE SFC DOES
NOT DECOUPLE ENOUGH...THE IMPACT OF HIGHER WINDS ON THE WIND CHILL
WILL BE GREATER THAN HAVING COLDER TEMPS...SO WIND CHILL HEADLINES
WILL NOT BE OUT OF THE QUESTION QUITE YET.
THURSDAY...WAA KICKS IN RIGHT AWAY THURSDAY MORNING AND WILL RESULT
IN A RELATIVELY WARMER DAY COMPARED TO WEDNESDAY. WEAK ISENTROPIC
LIFT WITH THIS WAA MAY PRODUCE A FEW LIGHT SNOW SHOWERS THURSDAY
MORNING ALONG THE WI BORDER...BUT DRY SUB-CLOUD AIR AND WEAK SUPPORT
WILL LIKELY LIMIT MOST PRECIPITATION FROM REACHING THE GROUND. THE
MID-LEVEL TROUGH AXIS ASSOCIATED WITH THE WEAK CLIPPER WILL BE
ENOUGH TO DISRUPT REMAINING LES.
FRIDAY THROUGH MONDAY...DID NOT MAKE MANY CHANGES TO THE FORECAST AS
DID NOT HAVE MUCH TIME TO DEVOTE TO THIS PERIOD AND MODEL
VARIABILITY HAS BEEN MORE THAN DESIRED. NW MID-LEVEL FLOW BEGINS TO
BREAK DOWN FRIDAY AFTERNOON INTO SATURDAY AS A TROUGH DIGS
SOUTHEASTWARD ACROSS THE NORTHERN PLAINS. A WEAK SHORTWAVE TROUGH
AHEAD OF THIS MAIN TROUGH IS PROGGED TO CROSS THE CWA FRIDAY NIGHT
INTO SATURDAY AND BRING A BOUT OF LIGHT SYNOPTIC SNOW. ONCE
AGAIN...DRY LOW-LEVELS WILL LIMIT THE POTENTIAL FOR MUCH MORE THAN A
DUSTING OF SNOW.
MODEL GUIDANCE IS STARTING TO PICK UP ON A STRONG SFC LOW DEVELOPING
ANYWHERE FROM THE OHIO VALLEY TO THE EASTERN SEABOARD SATURDAY NIGHT
INTO SUNDAY...DEPENDING ON HOW THE APPROACHING NORTHERN PLAINS WAVE
IMPACTS THE EASTERN CANADIAN TROUGH. A SECONDARY LOW IS ALSO PROGGED
TO DEVELOP ACROSS THE UPPER GREAT LAKES SATURDAY INTO SUNDAY ON THE
RIGHT ENTRANCE OF AN UPPER JET. OVERALL...FORECAST OF THE SYSTEM
DEVELOPMENT WILL REMAIN HIGHLY FLUID FOR THE COMING DAYS UNTIL THE
PHASING OF THE TROUGH/UPPER JETS IS WORKED OUT BY THE MODELS. WITH
THAT SAID...THE BEST POTENTIAL FOR WIDESPREAD SYNOPTIC SNOW WOULD BE
SATURDAY NIGHT AND SUNDAY. HOWEVER...LIMITED MOISTURE WILL ONCE
AGAIN BE AN ISSUE AND MAY RESULT IN MAINLY A LAKE-ENHANCED SNOWFALL.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z WEDNESDAY AFTERNOON)
ISSUED AT 1226 PM EST TUE DEC 10 2013
KIWD...EXPECT VFR CONDITIONS TO PREDOMINATE THRU THIS AFTN BEFORE A
LO PRES TROF CROSSES THE AREA THIS EVNG AND BRINGS SOME -SHSN/MVFR
CONDITIONS THAT WL PERSIST FOR THE REST OF THE FCST PERIOD.
KCMX...EXPECT IFR TO VLIFR CONDITIONS FOR THE FIRST FEW HRS OF THE
FCST PERIOD AS A HEAVIER SN BAND ALONG A LO PRES TROF CROSSES THE
KEWEENAW PENINSULA. WITH A WSHFT TO THE WNW AND GUSTY WINDS THRU THE
REST OF THE FCST PERIOD BEHIND THIS TROF...THE COMBINATION OF -SHSN/
BLSN SHOULD RESULT IN PREDOMINANT IFR/LIFR VSBYS.
KSAW...VFR CONDITIONS WILL CONTINUE THRU THE FORECAST PERIOD.
ALTHOUGH A LO PRES TROF WL CROSS THE AREA THIS EVNG...DOWNSLOPE
NATURE OF THE W WIND AND RELATIVE DRYNESS OF THE AIRMASS SHOULD
MAINTAIN THE VFR WX AT THIS SITE.
&&
.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 557 AM EST TUE DEC 10 2013
AFTER A DECREASE IN SOUTHWEST WINDS THIS MORNING...ANOTHER LOW
PRESSURE WILL TRACK EASTWARD ACROSS LAKE SUPERIOR AND COULD PRODUCE
GALES FOR THE SOUTH CENTRAL LAKE LATE THIS AFTERNOON INTO THIS
EVENING. THE WESTERLY WINDS WILL WEAKEN SLIGHTLY TO 20 TO 30 KNOTS
FROM LATE TUESDAY NIGHT INTO THURSDAY AS A WEAK RIDGE EXTENDING FROM
HIGH PRESSURE IN THE CENTRAL PLAINS SLOWLY BUILDS INTO THE AREA.
CONTINUED MODERATE TO HEAVY FREEZING SPRAY WILL BE POSSIBLE
THROUGHOUT THE PERIOD WITH SEVERAL PUSHES OF ARCTIC AIR ACROSS THE
LAKE. ANOTHER WEAK LOW PRESSURE SYSTEM WILL MOVE SOUTHEASTWARD
ACROSS LAKE SUPERIOR THURSDAY NIGHT INTO FRIDAY...BUT WINDS SHOULD
REMAIN UNDER 20 KNOTS THROUGH SATURDAY BEHIND THIS SYSTEM.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
LAKE EFFECT SNOW ADVISORY UNTIL 5 PM EST WEDNESDAY FOR MIZ004-
084.
LAKE EFFECT SNOW ADVISORY FROM 7 PM THIS EVENING TO MIDNIGHT EST
WEDNESDAY NIGHT FOR MIZ006.
LAKE EFFECT SNOW ADVISORY UNTIL MIDNIGHT EST WEDNESDAY NIGHT FOR
MIZ002-003.
LAKE EFFECT SNOW ADVISORY UNTIL 7 AM EST WEDNESDAY FOR MIZ001.
LAKE EFFECT SNOW ADVISORY UNTIL 11 AM CST WEDNESDAY FOR MIZ009.
LAKE EFFECT SNOW WARNING FROM 7 PM THIS EVENING TO 7 AM EST
THURSDAY FOR MIZ007.
LAKE SUPERIOR...
HEAVY FREEZING SPRAY WARNING FROM 6 PM THIS EVENING TO 6 PM EST
WEDNESDAY FOR LSZ266.
GALE WARNING FROM 6 PM THIS EVENING TO MIDNIGHT EST TONIGHT FOR
LSZ266.
HEAVY FREEZING SPRAY WARNING FROM 6 PM THIS EVENING TO 6 AM EST
THURSDAY FOR LSZ242>245-248>251-263>265.
HEAVY FREEZING SPRAY WARNING UNTIL 6 AM EST /5 AM CST/ THURSDAY
FOR LSZ162-240-241.
LAKE MICHIGAN...
HEAVY FREEZING SPRAY WARNING FROM 6 PM THIS EVENING TO 6 AM EST
WEDNESDAY FOR LMZ221-248-250.
&&
$$
SHORT TERM...VOSS
LONG TERM...KLUBER
AVIATION...KC
MARINE...VOSS
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
708 AM EST TUE DEC 10 2013
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 557 AM EST TUE DEC 10 2013
MAIN CONCERN IN SHORT TERM IS ANOTHER BOUT OF MODERATE TO HEAVY LES
EXPECTED TO BEGIN LATE THIS MORNING WEST AND TOWARD EVENING FAR
EAST. EXPECT THE PROLONGED LES EVENT TO CONTINUE THROUGH MUCH OF WED
FOR THE WEST AND THROUGH WED NIGHT FOR FAR ERN SHORELINE
AREAS.
WV IMAGERY AND RUC ANALYSIS INDICATED A BROAD TROUGH ACROSS NOAM.
THERE ARE TWO MAIN SHORTWAVES OF NOTE WITHIN THIS BROAD TROUGH. ONE
SHORTWAVE WAS MOVING EAST ACROSS MN WHILE A SECOND SHORTWAVE WAS
FARTHER UPSTREAM DIVING DOWN FROM SASKATCHEWAN. A SFC HIGH PRESSURE
RIDGE WAS STILL RESULTING IN GENERALLY CLEAR SKIES ACROSS MUCH OF
UPPER MI EARLY THIS MORNING. THE CLEAR SKIES HAVE ALLOWED TEMPS TO
DROP INTO SINGLE DIGITS BLO ZERO ACROSS MUCH OF THE AREA WITH A FEW
DOUBLE DIGIT BLO ZERO READINGS ALONG THE WI BDR. ASSOC FORCING AND
WEAK WAA AHEAD OF MN SHORTWAVE HAS BROUGHT SOME CLOUD COVER INTO
AREAS ALONG THE WI BDR. EXPECT THESE CLOUDS ALONG WITH SOME LIGHT
SNOW/FLURRIES TO SPREAD EAST ACROSS THE SRN TIER OF THE FCST AREA
THE REST OF THE MORNING BRINGING TEMPS UP A FEW DEGREES TOWARD
SUNRISE. WIND CHILLS HAVE HOVERED JUST BLO ADVISORY CRITERIA EARLY
THIS MORNING...GENERALLY FROM 15 TO 25 BELOW. WINDS BACKING SW AHEAD
OF APPROACHING TROUGH FROM MN HAVE ALSO PUSHED LES BANDS FM KEWEENAW
OUT OVER LAKE SUPERIOR EARLY THIS MORNING.
TODAY AND TONIGHT...THE MODERATE TO STRONG Q-VECT CONV ASSOC WITH MN
SHORTWAVE WILL LIKELY BRING A LIGHT DUSTING OF SNOW ACCUMULATION
(LESS THAN HALF AN INCH) TO MAINLY THE SRN PORTION OF THE CWA THIS
MORNING. THE SECOND SHORTWAVE MOVING DOWN FROM SASKATCHEWAN WILL
SPREAD MODERATE 700-300 MB QVECTOR CONV ACROSS LAKE SUPERIOR WHICH
WILL PROVIDE FOR A PERIOD OF ENHANCEMENT TO LES BANDS SETTING UP IN
STRONGLY CONVERGENT WRLY FLOW OVER THE MIDDLE OF THE LAKE.
WINDS VEERING IN THE WAKE OF THE SHRTWV SHOULD BRING ANOTHER STRONG
AREA OF LOW LEVEL CONV INTO NW UPPER MI AS THE SFC TROUGH MOVES
THROUGH AROUND 18Z. EXPECT ANOTHER PERIOD OF MODERATE TO HEAVY LES
OVER WRN UPR MI BEGINNING LATE THIS MORNING OVER KEWEENAW/NRN
HOUGHTON AND ONTONAGON COUNTIES AND EARLY THIS AFTERNOON FOR SRN
HOUGHTON/BARAGA AND GOGEBIC COUNTIES. WOULD NOT BE SURPRISED TO SEE
BRIEF 1-2 INCH SNOWFALL RATES AS DOMINANT LES BAND LIKELY TRAVERSES
THE AREA. STRONGLY CONVERGENT WNW FLOW WILL CONTINUE
TONIGHT...ESPECIALLY INTO HOUGHTON...ONTONAGON AND BARAGA COUNTIES
AS POTENTIAL FOR MODERATE TO HEAVY SNOW BAND COULD BRING ADDITIONAL
SIGNIFICANT ACCUMULATION. ALTHOUGH DGZ DOES COMPRESS INTO THE LOWEST
2KFT OF ATMOSPHERE UNDER FAIRLY STRONG CAA (8H TEMPS LOWER TO AROUND
-25C BY WED MORNING)...THERE IS STILL SOME MODEL OMEGA NOTED WITH
THIS LAYER. STRONG WINDS HOWEVER COULD RESULT IN FRACTURING OF
DENDRITES LEADING TO LOWER SLR THAN OTHERWISE EXPECTED. FOR NOW WILL
KEEP WITH THE NEAR 20/1 SLR FOR FIGURING SNOW ACCUMS. WITH THE
POTENTIAL FOR A PROLONGED LES EVENT IN STRONGLY CONVERGENT WNW
FLOW...HAVE DECIDED TO ISSUE LES ADVISORIES FOR THE 4 WRN COUNTIES
AND WILL ALSO INCLUDE BARAGA COUNTY. SOME LOCATIONS ESPECIALLY
FROM TWIN LAKES THROUGH PELKIE TO ROCKLAND WILL LIKELY EXCEED A FOOT
OF TOTAL SNOWFALL FROM LATE TODAY THROUGH WEDNESDAY.
WINDS VEERING OVER THE ERN LAKE THIS AFERNOON WILL BEGIN TO PUSH A
DOMINANT LES BAND ONSHORE OVER THE FAR ERN CWA THIS EVENING. STRONG
CONVERGENCE SETTING UP OVER THIS AREA TONIGHT INTO WEDNESDAY FROM
LAND BREEZES OFF ONTARIO AND UPPER MI WILL ALSO LEAD TO PROLONGED
PERIOD OF HEAVY LES AS INVERSIONS FROM 8-10 KFT ARE EXPECTED THROUGH
MUCH OF PD ALONG WITH FAIRLY FAVORABLE SNOW GROWTH. TOTAL SNOW
ACCUMS FROM TONIGHT THROUGH WED NIGHT COULD EXCEED 18 INCHES FROM
GRAND MARAIS TO TWO HEART ALONG THE LAKE SUPERIOR SHORE. AS A
RESULT...HAVE ISSUED A LONG TERM LES ADVISORY FOR ERN ALGER COUNTY
AND A LES WARNING FOR LUCE COUNTY.
WINDS CHILLS TONIGHT COULD APPROACH ADVISORY CRITERIA ESPECIALLY
ALONG THE WI BDR INTERIOR WEST AS ACTUAL TEMPS DROP NEAR
-10F.
.LONG TERM...(WEDNESDAY THROUGH MONDAY)
ISSUED AT 534 AM EST TUE DEC 10 2013
CONTINUED COLD WITH PERSISTENT LAKE EFFECT SNOWS THROUGH
THURSDAY...THEN A TREND TOWARD SLIGHTLY WARMER TEMPERATURES BY THE
WEEKEND.
WEDNESDAY AND WEDNESDAY NIGHT...DEEP TROUGHING OVER EASTERN CANADA
WILL CONTINUE TO SEND MULTIPLE WAVES ACROSS THE UPPER GREAT
LAKES...WITH THE FIRST TROUGH AXIS CROSSING UPPER MI AT THE START
OF THE PERIOD. MODERATE TO HEAVY LES WILL BE ONGOING FOR WNW SNOW
BELTS...ESPECIALLY ACROSS NORTHERN LUCE AND FAR EASTERN ALGER
COUNTIES WHERE A SFC LAKE-ENHANCED TROUGH WILL BE ASSISTING WITH
ABUNDANT LOW-LEVEL CONVERGENCE. AFTER COORDINATION WITH THE SHORT
TERM FORECASTER AND WFO GAYLORD...A LAKE EFFECT SNOW WARNING WAS
ISSUED FOR LUCE COUNTY THIS EVENING THROUGH WEDNESDAY NIGHT. SEE THE
SHORT TERM DISCUSSION FOR FURTHER DETAILS ABOUT THE LES POTENTIAL
TONIGHT.
THE MAIN SFC TROUGH OVER LAKE SUPERIOR TONIGHT WILL BE PUSHING
SOUTHWARD ACROSS THE EASTERN CWA WEDNESDAY MORNING WHILE A WEAK
LAKE-ENHANCED TROUGH REMAINS OVER EASTERN LAKE SUPERIOR. THE VEERING
OF WINDS BEHIND THE MAIN TROUGH WILL BE ENOUGH TO DISRUPT DOMINATE
LES BANDS AND SHOVE THEM FARTHER SOUTHWARD INTO LUCE AND ALGER
COUNTIES. A QUICK BURST OF SNOW CAN BE EXPECTED FOR MOST LOCATIONS
AS THIS OCCURS. MEANWHILE...MULTI-BAND LES WILL PERSIST ACROSS
WESTERN UPPER MI FOR WNW SNOW BELTS AS -25C H8 AIR CONTINUES TO
FILTER INTO THE CWA. THERE ARE SIGNS THAT A MORE DOMINATE BAND MAY
EXIST INTO CENTRAL HOUGHTON COUNTY AND FAR NORTHERN ONTONAGON
COUNTY DURING THE AFTERNOON...SO AMOUNTS SHOULD BE HIGHEST THERE.
INVERSION HEIGHTS FALLING TO BELOW 5KFT FOR THE ENTIRE AREA AND
BACKING WINDS AHEAD OF AN APPROACHING SFC RIDGE WILL REDUCE LES
INTENSITY GREATLY WEDNESDAY EVENING.
A VERY COLD WEDNESDAY NIGHT COULD BE IN STORE...THOUGH TEMPERATURES
WILL BE HINGING ON THE GRADIENT FLOW TO LAX BEFORE MID-LEVEL CLOUDS
BRUSH THE AREA LATE IN THE NIGHT. A SFC RIDGE AXIS WILL BE DRIFTING
ACROSS NORTHERN WI THROUGHOUT THE NIGHT...THOUGH CONTINUED MODEL
SUPPORT OF A LAKE-ENHANCED TROUGH OVER EASTERN LAKE SUPERIOR WILL
INCREASE THE PRESSURE GRADIENT ACROSS THE WESTERN CWA.
HOWEVER...SOUNDING FORECASTS FROM THE INTERIOR WEST SHOW DECENT
ENOUGH SFC DECOUPLING TO ALLOW FOR APPRECIABLE RADIATIONAL COOLING.
MID-LEVEL CLOUDS WILL BE ON THE RISE ACROSS MUCH OF WI LATE IN THE
NIGHT AS A VERY WEAK CLIPPER SYSTEM TRACKS SE TOWARD THE AREA. THIS
TRACK IS FARTHER SOUTH THAN PREVIOUSLY ADVERTISED BY THE
MODELS...WHICH SHOULD LIMIT THE OVERALL IMPACT OF CLOUD-COVER ON
TEMPS ACROSS THE CWA. WITH ALL THAT SAID...JUXTAPOSITION OF BEST
COOLING FACTORS SHOULD BE ACROSS THE INTERIOR CWA WHERE TEMPS COULD
BOTTOM OUT BELOW -20F. WITH GRADIENT FLOW OF 5-10 MPH...WIND CHILLS
WILL APPROACH -35F. ADVISORY/WARNING DECISIONS WILL BE TRICKY WITH
WINDS EXPECTED BELOW THE 10 MPH CRITERIA. HOWEVER...IF THE SFC DOES
NOT DECOUPLE ENOUGH...THE IMPACT OF HIGHER WINDS ON THE WIND CHILL
WILL BE GREATER THAN HAVING COLDER TEMPS...SO WIND CHILL HEADLINES
WILL NOT BE OUT OF THE QUESTION QUITE YET.
THURSDAY...WAA KICKS IN RIGHT AWAY THURSDAY MORNING AND WILL RESULT
IN A RELATIVELY WARMER DAY COMPARED TO WEDNESDAY. WEAK ISENTROPIC
LIFT WITH THIS WAA MAY PRODUCE A FEW LIGHT SNOW SHOWERS THURSDAY
MORNING ALONG THE WI BORDER...BUT DRY SUB-CLOUD AIR AND WEAK SUPPORT
WILL LIKELY LIMIT MOST PRECIPITATION FROM REACHING THE GROUND. THE
MID-LEVEL TROUGH AXIS ASSOCIATED WITH THE WEAK CLIPPER WILL BE
ENOUGH TO DISRUPT REMAINING LES.
FRIDAY THROUGH MONDAY...DID NOT MAKE MANY CHANGES TO THE FORECAST AS
DID NOT HAVE MUCH TIME TO DEVOTE TO THIS PERIOD AND MODEL
VARIABILITY HAS BEEN MORE THAN DESIRED. NW MID-LEVEL FLOW BEGINS TO
BREAK DOWN FRIDAY AFTERNOON INTO SATURDAY AS A TROUGH DIGS
SOUTHEASTWARD ACROSS THE NORTHERN PLAINS. A WEAK SHORTWAVE TROUGH
AHEAD OF THIS MAIN TROUGH IS PROGGED TO CROSS THE CWA FRIDAY NIGHT
INTO SATURDAY AND BRING A BOUT OF LIGHT SYNOPTIC SNOW. ONCE
AGAIN...DRY LOW-LEVELS WILL LIMIT THE POTENTIAL FOR MUCH MORE THAN A
DUSTING OF SNOW.
MODEL GUIDANCE IS STARTING TO PICK UP ON A STRONG SFC LOW DEVELOPING
ANYWHERE FROM THE OHIO VALLEY TO THE EASTERN SEABOARD SATURDAY NIGHT
INTO SUNDAY...DEPENDING ON HOW THE APPROACHING NORTHERN PLAINS WAVE
IMPACTS THE EASTERN CANADIAN TROUGH. A SECONDARY LOW IS ALSO PROGGED
TO DEVELOP ACROSS THE UPPER GREAT LAKES SATURDAY INTO SUNDAY ON THE
RIGHT ENTRANCE OF AN UPPER JET. OVERALL...FORECAST OF THE SYSTEM
DEVELOPMENT WILL REMAIN HIGHLY FLUID FOR THE COMING DAYS UNTIL THE
PHASING OF THE TROUGH/UPPER JETS IS WORKED OUT BY THE MODELS. WITH
THAT SAID...THE BEST POTENTIAL FOR WIDESPREAD SYNOPTIC SNOW WOULD BE
SATURDAY NIGHT AND SUNDAY. HOWEVER...LIMITED MOISTURE WILL ONCE
AGAIN BE AN ISSUE AND MAY RESULT IN MAINLY A LAKE-ENHANCED SNOWFALL.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z WEDNESDAY MORNING)
ISSUED AT 642 AM EST TUE DEC 10 2013
KIWD...LIGHT SNOW MOVING THROUGH THIS MORNING WILL PRODUCE BRIEF IFR
CONDITIONS. EXPECT CONDITIONS TO IMPROVE TO MVFR LATE THIS MORNING
AND AFTERNOON AS WSW FLOW INCREASES AND LIGHT LES BEGINS. MORE
FAVORABLE WRLY FLOW DEVELOPING LATE TONIGHT COULD SEND CONDITIONS
NEAR IFR AS HEAVIER LES BANDS COULD GLANCE THE TAF SITE.
KCMX...VFR CONDITIONS WILL QUICKLY LOWER TO VLIFR BY LATE MORNING AS
HEAVY LES AND BLSN MOVES INTO THE AREA. THERE COULD BE SLIGHT
IMPROVEMENT TO LIFR CONDITIONS LATE THIS AFTERNOON AND THEN TO IFR
THIS EVENING AS WINDS GRADUALLY VEER FROM WEST TO WNW PUSHING
HEAVIEST LES BANDS TO THE SOUTH.
KSAW...VFR CONDITIONS SHOULD CONTINUE THROUGH MUCH OF THE PERIOD IN A
STRENGHENING SW-W FLOW. SOME MVFR CONDITIONS MAY DEVELOP LATE
TONIGHT AS WINDS VEER WNW AS SOME LIGHT LES COULD WORK ITS WAY INTO
THE AREA.
&&
.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 557 AM EST TUE DEC 10 2013
AFTER A DECREASE IN SOUTHWEST WINDS THIS MORNING...ANOTHER LOW
PRESSURE WILL TRACK EASTWARD ACROSS LAKE SUPERIOR AND COULD PRODUCE
GALES FOR THE SOUTH CENTRAL LAKE LATE THIS AFTERNOON INTO THIS
EVENING. THE WESTERLY WINDS WILL WEAKEN SLIGHTLY TO 20 TO 30 KNOTS
FROM LATE TUESDAY NIGHT INTO THURSDAY AS A WEAK RIDGE EXTENDING FROM
HIGH PRESSURE IN THE CENTRAL PLAINS SLOWLY BUILDS INTO THE AREA.
CONTINUED MODERATE TO HEAVY FREEZING SPRAY WILL BE POSSIBLE
THROUGHOUT THE PERIOD WITH SEVERAL PUSHES OF ARCTIC AIR ACROSS THE
LAKE. ANOTHER WEAK LOW PRESSURE SYSTEM WILL MOVE SOUTHEASTWARD
ACROSS LAKE SUPERIOR THURSDAY NIGHT INTO FRIDAY...BUT WINDS SHOULD
REMAIN UNDER 20 KNOTS THROUGH SATURDAY BEHIND THIS SYSTEM.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
LAKE EFFECT SNOW ADVISORY FROM 11 AM THIS MORNING TO MIDNIGHT
EST WEDNESDAY NIGHT FOR MIZ002-003.
LAKE EFFECT SNOW ADVISORY FROM 10 AM THIS MORNING TO 7 AM EST
WEDNESDAY FOR MIZ001.
LAKE EFFECT SNOW ADVISORY FROM 1 PM THIS AFTERNOON TO 5 PM EST
WEDNESDAY FOR MIZ004-084.
LAKE EFFECT SNOW ADVISORY FROM NOON TODAY TO 11 AM CST WEDNESDAY
FOR MIZ009.
LAKE EFFECT SNOW WARNING FROM 7 PM THIS EVENING TO 7 AM EST
THURSDAY FOR MIZ007.
LAKE EFFECT SNOW ADVISORY FROM 7 PM THIS EVENING TO MIDNIGHT EST
WEDNESDAY NIGHT FOR MIZ006.
LAKE SUPERIOR...
HEAVY FREEZING SPRAY WARNING UNTIL 10 AM EST THIS MORNING FOR
LSZ245-248>251-265>267.
GALE WARNING FROM 6 PM THIS EVENING TO MIDNIGHT EST TONIGHT FOR
LSZ266.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...VOSS
LONG TERM...KLUBER
AVIATION...VOSS
MARINE...VOSS
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
558 AM EST TUE DEC 10 2013
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 557 AM EST TUE DEC 10 2013
MAIN CONCERN IN SHORT TERM IS ANOTHER BOUT OF MODERATE TO HEAVY LES
EXPECTED TO BEGIN LATE THIS MORNING WEST AND TOWARD EVENING FAR
EAST. EXPECT THE PROLONGED LES EVENT TO CONTINUE THROUGH MUCH OF WED
FOR THE WEST AND THROUGH WED NIGHT FOR FAR ERN SHORELINE
AREAS.
WV IMAGERY AND RUC ANALYSIS INDICATED A BROAD TROUGH ACROSS NOAM.
THERE ARE TWO MAIN SHORTWAVES OF NOTE WITHIN THIS BROAD TROUGH. ONE
SHORTWAVE WAS MOVING EAST ACROSS MN WHILE A SECOND SHORTWAVE WAS
FARTHER UPSTREAM DIVING DOWN FROM SASKATCHEWAN. A SFC HIGH PRESSURE
RIDGE WAS STILL RESULTING IN GENERALLY CLEAR SKIES ACROSS MUCH OF
UPPER MI EARLY THIS MORNING. THE CLEAR SKIES HAVE ALLOWED TEMPS TO
DROP INTO SINGLE DIGITS BLO ZERO ACROSS MUCH OF THE AREA WITH A FEW
DOUBLE DIGIT BLO ZERO READINGS ALONG THE WI BDR. ASSOC FORCING AND
WEAK WAA AHEAD OF MN SHORTWAVE HAS BROUGHT SOME CLOUD COVER INTO
AREAS ALONG THE WI BDR. EXPECT THESE CLOUDS ALONG WITH SOME LIGHT
SNOW/FLURRIES TO SPREAD EAST ACROSS THE SRN TIER OF THE FCST AREA
THE REST OF THE MORNING BRINGING TEMPS UP A FEW DEGREES TOWARD
SUNRISE. WIND CHILLS HAVE HOVERED JUST BLO ADVISORY CRITERIA EARLY
THIS MORNING...GENERALLY FROM 15 TO 25 BELOW. WINDS BACKING SW AHEAD
OF APPROACHING TROUGH FROM MN HAVE ALSO PUSHED LES BANDS FM KEWEENAW
OUT OVER LAKE SUPERIOR EARLY THIS MORNING.
TODAY AND TONIGHT...THE MODERATE TO STRONG Q-VECT CONV ASSOC WITH MN
SHORTWAVE WILL LIKELY BRING A LIGHT DUSTING OF SNOW ACCUMULATION
(LESS THAN HALF AN INCH) TO MAINLY THE SRN PORTION OF THE CWA THIS
MORNING. THE SECOND SHORTWAVE MOVING DOWN FROM SASKATCHEWAN WILL
SPREAD MODERATE 700-300 MB QVECTOR CONV ACROSS LAKE SUPERIOR WHICH
WILL PROVIDE FOR A PERIOD OF ENHANCEMENT TO LES BANDS SETTING UP IN
STRONGLY CONVERGENT WRLY FLOW OVER THE MIDDLE OF THE LAKE.
WINDS VEERING IN THE WAKE OF THE SHRTWV SHOULD BRING ANOTHER STRONG
AREA OF LOW LEVEL CONV INTO NW UPPER MI AS THE SFC TROUGH MOVES
THROUGH AROUND 18Z. EXPECT ANOTHER PERIOD OF MODERATE TO HEAVY LES
OVER WRN UPR MI BEGINNING LATE THIS MORNING OVER KEWEENAW/NRN
HOUGHTON AND ONTONAGON COUNTIES AND EARLY THIS AFTERNOON FOR SRN
HOUGHTON/BARAGA AND GOGEBIC COUNTIES. WOULD NOT BE SURPRISED TO SEE
BRIEF 1-2 INCH SNOWFALL RATES AS DOMINANT LES BAND LIKELY TRAVERSES
THE AREA. STRONGLY CONVERGENT WNW FLOW WILL CONTINUE
TONIGHT...ESPECIALLY INTO HOUGHTON...ONTONAGON AND BARAGA COUNTIES
AS POTENTIAL FOR MODERATE TO HEAVY SNOW BAND COULD BRING ADDITIONAL
SIGNIFICANT ACCUMULATION. ALTHOUGH DGZ DOES COMPRESS INTO THE LOWEST
2KFT OF ATMOSPHERE UNDER FAIRLY STRONG CAA (8H TEMPS LOWER TO AROUND
-25C BY WED MORNING)...THERE IS STILL SOME MODEL OMEGA NOTED WITH
THIS LAYER. STRONG WINDS HOWEVER COULD RESULT IN FRACTURING OF
DENDRITES LEADING TO LOWER SLR THAN OTHERWISE EXPECTED. FOR NOW WILL
KEEP WITH THE NEAR 20/1 SLR FOR FIGURING SNOW ACCUMS. WITH THE
POTENTIAL FOR A PROLONGED LES EVENT IN STRONGLY CONVERGENT WNW
FLOW...HAVE DECIDED TO ISSUE LES ADVISORIES FOR THE 4 WRN COUNTIES
AND WILL ALSO INCLUDE BARAGA COUNTY. SOME LOCATIONS ESPECIALLY
FROM TWIN LAKES THROUGH PELKIE TO ROCKLAND WILL LIKELY EXCEED A FOOT
OF TOTAL SNOWFALL FROM LATE TODAY THROUGH WEDNESDAY.
WINDS VEERING OVER THE ERN LAKE THIS AFERNOON WILL BEGIN TO PUSH A
DOMINANT LES BAND ONSHORE OVER THE FAR ERN CWA THIS EVENING. STRONG
CONVERGENCE SETTING UP OVER THIS AREA TONIGHT INTO WEDNESDAY FROM
LAND BREEZES OFF ONTARIO AND UPPER MI WILL ALSO LEAD TO PROLONGED
PERIOD OF HEAVY LES AS INVERSIONS FROM 8-10 KFT ARE EXPECTED THROUGH
MUCH OF PD ALONG WITH FAIRLY FAVORABLE SNOW GROWTH. TOTAL SNOW
ACCUMS FROM TONIGHT THROUGH WED NIGHT COULD EXCEED 18 INCHES FROM
GRAND MARAIS TO TWO HEART ALONG THE LAKE SUPERIOR SHORE. AS A
RESULT...HAVE ISSUED A LONG TERM LES ADVISORY FOR ERN ALGER COUNTY
AND A LES WARNING FOR LUCE COUNTY.
WINDS CHILLS TONIGHT COULD APPROACH ADVISORY CRITERIA ESPECIALLY
ALONG THE WI BDR INTERIOR WEST AS ACTUAL TEMPS DROP NEAR
-10F.
.LONG TERM...(WEDNESDAY THROUGH MONDAY)
ISSUED AT 534 AM EST TUE DEC 10 2013
CONTINUED COLD WITH PERSISTENT LAKE EFFECT SNOWS THROUGH
THURSDAY...THEN A TREND TOWARD SLIGHTLY WARMER TEMPERATURES BY THE
WEEKEND.
WEDNESDAY AND WEDNESDAY NIGHT...DEEP TROUGHING OVER EASTERN CANADA
WILL CONTINUE TO SEND MULTIPLE WAVES ACROSS THE UPPER GREAT
LAKES...WITH THE FIRST TROUGH AXIS CROSSING UPPER MI AT THE START
OF THE PERIOD. MODERATE TO HEAVY LES WILL BE ONGOING FOR WNW SNOW
BELTS...ESPECIALLY ACROSS NORTHERN LUCE AND FAR EASTERN ALGER
COUNTIES WHERE A SFC LAKE-ENHANCED TROUGH WILL BE ASSISTING WITH
ABUNDANT LOW-LEVEL CONVERGENCE. AFTER COORDINATION WITH THE SHORT
TERM FORECASTER AND WFO GAYLORD...A LAKE EFFECT SNOW WARNING WAS
ISSUED FOR LUCE COUNTY THIS EVENING THROUGH WEDNESDAY NIGHT. SEE THE
SHORT TERM DISCUSSION FOR FURTHER DETAILS ABOUT THE LES POTENTIAL
TONIGHT.
THE MAIN SFC TROUGH OVER LAKE SUPERIOR TONIGHT WILL BE PUSHING
SOUTHWARD ACROSS THE EASTERN CWA WEDNESDAY MORNING WHILE A WEAK
LAKE-ENHANCED TROUGH REMAINS OVER EASTERN LAKE SUPERIOR. THE VEERING
OF WINDS BEHIND THE MAIN TROUGH WILL BE ENOUGH TO DISRUPT DOMINATE
LES BANDS AND SHOVE THEM FARTHER SOUTHWARD INTO LUCE AND ALGER
COUNTIES. A QUICK BURST OF SNOW CAN BE EXPECTED FOR MOST LOCATIONS
AS THIS OCCURS. MEANWHILE...MULTI-BAND LES WILL PERSIST ACROSS
WESTERN UPPER MI FOR WNW SNOW BELTS AS -25C H8 AIR CONTINUES TO
FILTER INTO THE CWA. THERE ARE SIGNS THAT A MORE DOMINATE BAND MAY
EXIST INTO CENTRAL HOUGHTON COUNTY AND FAR NORTHERN ONTONAGON
COUNTY DURING THE AFTERNOON...SO AMOUNTS SHOULD BE HIGHEST THERE.
INVERSION HEIGHTS FALLING TO BELOW 5KFT FOR THE ENTIRE AREA AND
BACKING WINDS AHEAD OF AN APPROACHING SFC RIDGE WILL REDUCE LES
INTENSITY GREATLY WEDNESDAY EVENING.
A VERY COLD WEDNESDAY NIGHT COULD BE IN STORE...THOUGH TEMPERATURES
WILL BE HINGING ON THE GRADIENT FLOW TO LAX BEFORE MID-LEVEL CLOUDS
BRUSH THE AREA LATE IN THE NIGHT. A SFC RIDGE AXIS WILL BE DRIFTING
ACROSS NORTHERN WI THROUGHOUT THE NIGHT...THOUGH CONTINUED MODEL
SUPPORT OF A LAKE-ENHANCED TROUGH OVER EASTERN LAKE SUPERIOR WILL
INCREASE THE PRESSURE GRADIENT ACROSS THE WESTERN CWA.
HOWEVER...SOUNDING FORECASTS FROM THE INTERIOR WEST SHOW DECENT
ENOUGH SFC DECOUPLING TO ALLOW FOR APPRECIABLE RADIATIONAL COOLING.
MID-LEVEL CLOUDS WILL BE ON THE RISE ACROSS MUCH OF WI LATE IN THE
NIGHT AS A VERY WEAK CLIPPER SYSTEM TRACKS SE TOWARD THE AREA. THIS
TRACK IS FARTHER SOUTH THAN PREVIOUSLY ADVERTISED BY THE
MODELS...WHICH SHOULD LIMIT THE OVERALL IMPACT OF CLOUD-COVER ON
TEMPS ACROSS THE CWA. WITH ALL THAT SAID...JUXTAPOSITION OF BEST
COOLING FACTORS SHOULD BE ACROSS THE INTERIOR CWA WHERE TEMPS COULD
BOTTOM OUT BELOW -20F. WITH GRADIENT FLOW OF 5-10 MPH...WIND CHILLS
WILL APPROACH -35F. ADVISORY/WARNING DECISIONS WILL BE TRICKY WITH
WINDS EXPECTED BELOW THE 10 MPH CRITERIA. HOWEVER...IF THE SFC DOES
NOT DECOUPLE ENOUGH...THE IMPACT OF HIGHER WINDS ON THE WIND CHILL
WILL BE GREATER THAN HAVING COLDER TEMPS...SO WIND CHILL HEADLINES
WILL NOT BE OUT OF THE QUESTION QUITE YET.
THURSDAY...WAA KICKS IN RIGHT AWAY THURSDAY MORNING AND WILL RESULT
IN A RELATIVELY WARMER DAY COMPARED TO WEDNESDAY. WEAK ISENTROPIC
LIFT WITH THIS WAA MAY PRODUCE A FEW LIGHT SNOW SHOWERS THURSDAY
MORNING ALONG THE WI BORDER...BUT DRY SUB-CLOUD AIR AND WEAK SUPPORT
WILL LIKELY LIMIT MOST PRECIPITATION FROM REACHING THE GROUND. THE
MID-LEVEL TROUGH AXIS ASSOCIATED WITH THE WEAK CLIPPER WILL BE
ENOUGH TO DISRUPT REMAINING LES.
FRIDAY THROUGH MONDAY...DID NOT MAKE MANY CHANGES TO THE FORECAST AS
DID NOT HAVE MUCH TIME TO DEVOTE TO THIS PERIOD AND MODEL
VARIABILITY HAS BEEN MORE THAN DESIRED. NW MID-LEVEL FLOW BEGINS TO
BREAK DOWN FRIDAY AFTERNOON INTO SATURDAY AS A TROUGH DIGS
SOUTHEASTWARD ACROSS THE NORTHERN PLAINS. A WEAK SHORTWAVE TROUGH
AHEAD OF THIS MAIN TROUGH IS PROGGED TO CROSS THE CWA FRIDAY NIGHT
INTO SATURDAY AND BRING A BOUT OF LIGHT SYNOPTIC SNOW. ONCE
AGAIN...DRY LOW-LEVELS WILL LIMIT THE POTENTIAL FOR MUCH MORE THAN A
DUSTING OF SNOW.
MODEL GUIDANCE IS STARTING TO PICK UP ON A STRONG SFC LOW DEVELOPING
ANYWHERE FROM THE OHIO VALLEY TO THE EASTERN SEABOARD SATURDAY NIGHT
INTO SUNDAY...DEPENDING ON HOW THE APPROACHING NORTHERN PLAINS WAVE
IMPACTS THE EASTERN CANADIAN TROUGH. A SECONDARY LOW IS ALSO PROGGED
TO DEVELOP ACROSS THE UPPER GREAT LAKES SATURDAY INTO SUNDAY ON THE
RIGHT ENTRANCE OF AN UPPER JET. OVERALL...FORECAST OF THE SYSTEM
DEVELOPMENT WILL REMAIN HIGHLY FLUID FOR THE COMING DAYS UNTIL THE
PHASING OF THE TROUGH/UPPER JETS IS WORKED OUT BY THE MODELS. WITH
THAT SAID...THE BEST POTENTIAL FOR WIDESPREAD SYNOPTIC SNOW WOULD BE
SATURDAY NIGHT AND SUNDAY. HOWEVER...LIMITED MOISTURE WILL ONCE
AGAIN BE AN ISSUE AND MAY RESULT IN MAINLY A LAKE-ENHANCED SNOWFALL.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z TUESDAY NIGHT)
ISSUED AT 1239 AM EST TUE DEC 10 2013
KIWD...WILL BE VFR THROUGH TONIGHT. MVFR CONDITIONS IN LIGHT SNOW
RETURN TUE MORNING WITH APPROACH OF NEXT DISTURBANCE FROM THE
NORTHERN PLAINS AND THIS REMAINS THROUGH THE REST OF THE FORECAST
PERIOD.
KCMX...IFR CONDITIONS WITH LIGHT LAKE EFFECT SNOW WILL IMPROVE TO
MVFR LATER TONIGHT AS THE WIND BACKS TO THE SW AND THE HEAVIER LES
BANDS SHIFT NORTH OF THE AREA. AS WINDS GO BACK WEST BY TUE
AFTERNOON...CONDITIONS WILL DETERIORATE AGAIN TO VLIFR WITH BLOWING
SNOW AND HEAVIER LAKE EFFECT SNOW BANDS AFFECTING THE TAF SITE
THROUGH TUE EVENING.
KSAW...VFR CONDITIONS WILL CONTINUE THROUGH THE FORECAST PERIOD. THE
NEXT SHORTWAVE TROUGH MOVING INTO THE AREA TUE MORNING WILL BRING
ANOTHER PERIOD WITH SOME LIGHT SNOW SHOWERS OR FLURRIES INTO EARLY
TUE AFTERNOON.
&&
.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 557 AM EST TUE DEC 10 2013
AFTER A DECREASE IN SOUTHWEST WINDS THIS MORNING...ANOTHER LOW
PRESSURE WILL TRACK EASTWARD ACROSS LAKE SUPERIOR AND COULD PRODUCE
GALES FOR THE SOUTH CENTRAL LAKE LATE THIS AFTERNOON INTO THIS
EVENING. THE WESTERLY WINDS WILL WEAKEN SLIGHTLY TO 20 TO 30 KNOTS
FROM LATE TUESDAY NIGHT INTO THURSDAY AS A WEAK RIDGE EXTENDING FROM
HIGH PRESSURE IN THE CENTRAL PLAINS SLOWLY BUILDS INTO THE AREA.
CONTINUED MODERATE TO HEAVY FREEZING SPRAY WILL BE POSSIBLE
THROUGHOUT THE PERIOD WITH SEVERAL PUSHES OF ARCTIC AIR ACROSS THE
LAKE. ANOTHER WEAK LOW PRESSURE SYSTEM WILL MOVE SOUTHEASTWARD
ACROSS LAKE SUPERIOR THURSDAY NIGHT INTO FRIDAY...BUT WINDS SHOULD
REMAIN UNDER 20 KNOTS THROUGH SATURDAY BEHIND THIS SYSTEM.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
LAKE EFFECT SNOW ADVISORY FROM 11 AM THIS MORNING TO MIDNIGHT
EST WEDNESDAY NIGHT FOR MIZ002-003.
LAKE EFFECT SNOW ADVISORY FROM 10 AM THIS MORNING TO 7 AM EST
WEDNESDAY FOR MIZ001.
LAKE EFFECT SNOW ADVISORY FROM 1 PM THIS AFTERNOON TO 5 PM EST
WEDNESDAY FOR MIZ004-084.
LAKE EFFECT SNOW ADVISORY FROM NOON TODAY TO 11 AM CST WEDNESDAY
FOR MIZ009.
LAKE EFFECT SNOW WARNING FROM 7 PM THIS EVENING TO 7 AM EST
THURSDAY FOR MIZ007.
LAKE EFFECT SNOW ADVISORY FROM 7 PM THIS EVENING TO MIDNIGHT EST
WEDNESDAY NIGHT FOR MIZ006.
LAKE SUPERIOR...
HEAVY FREEZING SPRAY WARNING UNTIL 10 AM EST THIS MORNING FOR
LSZ245-248>251-265>267.
GALE WARNING FROM 6 PM THIS EVENING TO MIDNIGHT EST TONIGHT FOR
LSZ266.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...VOSS
LONG TERM...KLUBER
AVIATION...07
MARINE...VOSS
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
534 AM EST TUE DEC 10 2013
.SHORT TERM...(THIS EVENING THROUGH TUESDAY)
ISSUED AT 426 PM EST MON DEC 9 2013
WV IMAGERY AND RUC ANALYSIS INDICATED A BROAD TROUGH ACROSS NOAM.
ONE SHORTWAVE TROUGH EXTENDED FROM NW ONTARIO THROUGH WRN LAKE
SUPERIOR WHILE ANOTHER UPSTREAM SHRTWV WAS MOVING FROM SE SASK
TOWARD THE NRN PLAINS. AT THE SFC...A WEAK RIDGE OVER WRN MN
SEPARATED LOWS NE OF LAKE SUPERIOR AND OVER NE MONTANA. WSW WINDS
ACROSS WRN LAKE SUPERIOR WERE SLOWLY VEERING AS THE SHRTWV ADVANCES
THROUGH THE AREA. THE INITIAL DOMINANT BAND THROUGH THE NRN KEWEENAW
EARLY THIS AFTERNOON HAD LIFTED BACK TO THE NORTH.
HOWEVER...MULTIPLE WIND PARALLEL BANDS INTO THE NRN HALF OF THE
KEWEENAW HAVE INTENSIFIED THIS AFTERNOON...AIDED BY THE SHRTWV WHICH
HAS BOOSTED INVERSION HEIGHTS TO AROUND 9K FT AS 850 MB TEMPS DROP
INTO THE -18C TO -21C RANGE.
TONIGHT...
THE HIGH RES MODELS WERE IN GOOD AGREEMENT AND SUPPORT
UPSTREAM TRENDS OF LOW LEVEL WINDS VEERING THIS EVENING WHICH SHOULD
PUSH HEAVY LES BANDS OVER THE KEWEENAW GRADUALLY TO THE SOUTH.
HOWEVER...THE SRN EXTENT OF THE LES IS EXPECTED TO REMAIN MAINLY
NORTH OF M-38. SLR VALUES MAY BE LIMITED BY THE VERY COLD INCOMING
ARCTIC AIRMASS WHICH WILL KEEP THE DGZ BELOW 2K FT. GIVEN THE
FAVORABLE LOW LEVEL CONV PERSISTING THROUGH MUCH OF THE EVENING
BEFORE WINDS BACK AHEAD OF THE NEXT SHORTWAVE...ADDITIONAL
ACCUMULATIONS IN THE 3 TO 6 INCH RANGE ARE LIKELY. BY 12Z...EXPECT
THAT THE HEAVIER LES SHOULD LIFT TOWARD EAGLE RIVER AND COPPER
HARBOR BEFORE MOVING OFFHSORE TUE MORNING. STRONG WRLY GUSTING TO 35
MPH WILL ALSO CAUSE SIGNIFICANT BLOWING AND DRIFTING IN OPEN AREAS
WITH VSBY AOB 1/4SM IN THE HEAVIER LES BANDS BEFORE TAPER OFF AFTER
03Z/TUE.
TEMPERATURES DROPPING INTO THE ZERO TO 10 BELOW RANGE WITH WINDS OF
10 TO 15 MPH MAY DROP WIND CHILL VALUES TO 15 BELOW TO 25 BELOW THIS
EVENING. HOWEVER...WINDS ARE EXPECTED TO DIMINISH TO 7 MPH OR LESS
OVER THE COLDER INLAND AREAS...KEEPING WIND CHILLS FROM REACHING
ADVISORY THRESHOLD. IN ADDITION...CLOUDS WILL THICKEN LATE AS THE
SHRTWV APPROACHES BRINGING SLOWLY CLIMBING TEMPS LATE.
TUESDAY...
THE SASK SHRTWV WILL MOVE THROUGH THE REGION WITH MODERATE TO STRONG
700-300 MB QVECTOR CONV. EVEN THOUGH THE STRONGEST FORCING IS
EXPECTED JUST TO THE SOUTH OF UPPER MICHIGAN...IT SHOULD STILL BE
STRONG ENOUGH OVER UPPER MI TO SQUEEZE OUT SOME LIGHT SNOW WITH A
FEW HUNDREDTHS QPF IN THE VERY DRY AIRMASS. OVERALL ACCUMULATIONS
SHOULD REMAIN BELOW A HALF INCH BUT SHOULD BE WIDESPREAD ENOUGH TO
INCLUDE LIKELY POPS. VEERING WINDS IN THE WAKE OF THE SHRTWV SHOULD
BRING ANOTHER STRONG AREA OF LOW LEVEL CONV INTO NW UPPER MI AS THE
SFC TROUGH MOVES THROUGH AROUND 18Z. ANOTHER PERIOD OF HEAVIER LES
IS EXPECTED WITH THIS FEATURE THAT COULD PRODUCE 2 TO 4 INCHES OF
SNOW. SINCE THERE IS A GAP BETWEEN THE MON NIGHT LES AND THE NEXT
BATCH THE HEADLINE WAS NOT EXTENDED AT THIS TIME.
.LONG TERM...(WEDNESDAY THROUGH MONDAY)
ISSUED AT 534 AM EST TUE DEC 10 2013
CONTINUED COLD WITH PERSISTENT LAKE EFFECT SNOWS THROUGH
THURSDAY...THEN A TREND TOWARD SLIGHTLY WARMER TEMPERATURES BY THE
WEEKEND.
WEDNESDAY AND WEDNESDAY NIGHT...DEEP TROUGHING OVER EASTERN CANADA
WILL CONTINUE TO SEND MULTIPLE WAVES ACROSS THE UPPER GREAT
LAKES...WITH THE FIRST TROUGH AXIS CROSSING UPPER MI AT THE START
OF THE PERIOD. MODERATE TO HEAVY LES WILL BE ONGOING FOR WNW SNOW
BELTS...ESPECIALLY ACROSS NORTHERN LUCE AND FAR EASTERN ALGER
COUNTIES WHERE A SFC LAKE-ENHANCED TROUGH WILL BE ASSISTING WITH
ABUNDANT LOW-LEVEL CONVERGENCE. AFTER COORDINATION WITH THE SHORT
TERM FORECASTER AND WFO GAYLORD...A LAKE EFFECT SNOW WARNING WAS
ISSUED FOR LUCE COUNTY THIS EVENING THROUGH WEDNESDAY NIGHT. SEE THE
SHORT TERM DISCUSSION FOR FURTHER DETAILS ABOUT THE LES POTENTIAL
TONIGHT.
THE MAIN SFC TROUGH OVER LAKE SUPERIOR TONIGHT WILL BE PUSHING
SOUTHWARD ACROSS THE EASTERN CWA WEDNESDAY MORNING WHILE A WEAK
LAKE-ENHANCED TROUGH REMAINS OVER EASTERN LAKE SUPERIOR. THE VEERING
OF WINDS BEHIND THE MAIN TROUGH WILL BE ENOUGH TO DISRUPT DOMINATE
LES BANDS AND SHOVE THEM FARTHER SOUTHWARD INTO LUCE AND ALGER
COUNTIES. A QUICK BURST OF SNOW CAN BE EXPECTED FOR MOST LOCATIONS
AS THIS OCCURS. MEANWHILE...MULTI-BAND LES WILL PERSIST ACROSS
WESTERN UPPER MI FOR WNW SNOW BELTS AS -25C H8 AIR CONTINUES TO
FILTER INTO THE CWA. THERE ARE SIGNS THAT A MORE DOMINATE BAND MAY
EXIST INTO CENTRAL HOUGHTON COUNTY AND FAR NORTHERN ONTONAGON
COUNTY DURING THE AFTERNOON...SO AMOUNTS SHOULD BE HIGHEST THERE.
INVERSION HEIGHTS FALLING TO BELOW 5KFT FOR THE ENTIRE AREA AND
BACKING WINDS AHEAD OF AN APPROACHING SFC RIDGE WILL REDUCE LES
INTENSITY GREATLY WEDNESDAY EVENING.
A VERY COLD WEDNESDAY NIGHT COULD BE IN STORE...THOUGH TEMPERATURES
WILL BE HINGING ON THE GRADIENT FLOW TO LAX BEFORE MID-LEVEL CLOUDS
BRUSH THE AREA LATE IN THE NIGHT. A SFC RIDGE AXIS WILL BE DRIFTING
ACROSS NORTHERN WI THROUGHOUT THE NIGHT...THOUGH CONTINUED MODEL
SUPPORT OF A LAKE-ENHANCED TROUGH OVER EASTERN LAKE SUPERIOR WILL
INCREASE THE PRESSURE GRADIENT ACROSS THE WESTERN CWA.
HOWEVER...SOUNDING FORECASTS FROM THE INTERIOR WEST SHOW DECENT
ENOUGH SFC DECOUPLING TO ALLOW FOR APPRECIABLE RADIATIONAL COOLING.
MID-LEVEL CLOUDS WILL BE ON THE RISE ACROSS MUCH OF WI LATE IN THE
NIGHT AS A VERY WEAK CLIPPER SYSTEM TRACKS SE TOWARD THE AREA. THIS
TRACK IS FARTHER SOUTH THAN PREVIOUSLY ADVERTISED BY THE
MODELS...WHICH SHOULD LIMIT THE OVERALL IMPACT OF CLOUD-COVER ON
TEMPS ACROSS THE CWA. WITH ALL THAT SAID...JUXTAPOSITION OF BEST
COOLING FACTORS SHOULD BE ACROSS THE INTERIOR CWA WHERE TEMPS COULD
BOTTOM OUT BELOW -20F. WITH GRADIENT FLOW OF 5-10 MPH...WIND CHILLS
WILL APPROACH -35F. ADVISORY/WARNING DECISIONS WILL BE TRICKY WITH
WINDS EXPECTED BELOW THE 10 MPH CRITERIA. HOWEVER...IF THE SFC DOES
NOT DECOUPLE ENOUGH...THE IMPACT OF HIGHER WINDS ON THE WIND CHILL
WILL BE GREATER THAN HAVING COLDER TEMPS...SO WIND CHILL HEADLINES
WILL NOT BE OUT OF THE QUESTION QUITE YET.
THURSDAY...WAA KICKS IN RIGHT AWAY THURSDAY MORNING AND WILL RESULT
IN A RELATIVELY WARMER DAY COMPARED TO WEDNESDAY. WEAK ISENTROPIC
LIFT WITH THIS WAA MAY PRODUCE A FEW LIGHT SNOW SHOWERS THURSDAY
MORNING ALONG THE WI BORDER...BUT DRY SUB-CLOUD AIR AND WEAK SUPPORT
WILL LIKELY LIMIT MOST PRECIPITATION FROM REACHING THE GROUND. THE
MID-LEVEL TROUGH AXIS ASSOCIATED WITH THE WEAK CLIPPER WILL BE
ENOUGH TO DISRUPT REMAINING LES.
FRIDAY THROUGH MONDAY...DID NOT MAKE MANY CHANGES TO THE FORECAST AS
DID NOT HAVE MUCH TIME TO DEVOTE TO THIS PERIOD AND MODEL
VARIABILITY HAS BEEN MORE THAN DESIRED. NW MID-LEVEL FLOW BEGINS TO
BREAK DOWN FRIDAY AFTERNOON INTO SATURDAY AS A TROUGH DIGS
SOUTHEASTWARD ACROSS THE NORTHERN PLAINS. A WEAK SHORTWAVE TROUGH
AHEAD OF THIS MAIN TROUGH IS PROGGED TO CROSS THE CWA FRIDAY NIGHT
INTO SATURDAY AND BRING A BOUT OF LIGHT SYNOPTIC SNOW. ONCE
AGAIN...DRY LOW-LEVELS WILL LIMIT THE POTENTIAL FOR MUCH MORE THAN A
DUSTING OF SNOW.
MODEL GUIDANCE IS STARTING TO PICK UP ON A STRONG SFC LOW DEVELOPING
ANYWHERE FROM THE OHIO VALLEY TO THE EASTERN SEABOARD SATURDAY NIGHT
INTO SUNDAY...DEPENDING ON HOW THE APPROACHING NORTHERN PLAINS WAVE
IMPACTS THE EASTERN CANADIAN TROUGH. A SECONDARY LOW IS ALSO PROGGED
TO DEVELOP ACROSS THE UPPER GREAT LAKES SATURDAY INTO SUNDAY ON THE
RIGHT ENTRANCE OF AN UPPER JET. OVERALL...FORECAST OF THE SYSTEM
DEVELOPMENT WILL REMAIN HIGHLY FLUID FOR THE COMING DAYS UNTIL THE
PHASING OF THE TROUGH/UPPER JETS IS WORKED OUT BY THE MODELS. WITH
THAT SAID...THE BEST POTENTIAL FOR WIDESPREAD SYNOPTIC SNOW WOULD BE
SATURDAY NIGHT AND SUNDAY. HOWEVER...LIMITED MOISTURE WILL ONCE
AGAIN BE AN ISSUE AND MAY RESULT IN MAINLY A LAKE-ENHANCED SNOWFALL.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z TUESDAY NIGHT)
ISSUED AT 1239 AM EST TUE DEC 10 2013
KIWD...WILL BE VFR THROUGH TONIGHT. MVFR CONDITIONS IN LIGHT SNOW
RETURN TUE MORNING WITH APPROACH OF NEXT DISTURBANCE FROM THE
NORTHERN PLAINS AND THIS REMAINS THROUGH THE REST OF THE FORECAST
PERIOD.
KCMX...IFR CONDITIONS WITH LIGHT LAKE EFFECT SNOW WILL IMPROVE TO
MVFR LATER TONIGHT AS THE WIND BACKS TO THE SW AND THE HEAVIER LES
BANDS SHIFT NORTH OF THE AREA. AS WINDS GO BACK WEST BY TUE
AFTERNOON...CONDITIONS WILL DETERIORATE AGAIN TO VLIFR WITH BLOWING
SNOW AND HEAVIER LAKE EFFECT SNOW BANDS AFFECTING THE TAF SITE
THROUGH TUE EVENING.
KSAW...VFR CONDITIONS WILL CONTINUE THROUGH THE FORECAST PERIOD. THE
NEXT SHORTWAVE TROUGH MOVING INTO THE AREA TUE MORNING WILL BRING
ANOTHER PERIOD WITH SOME LIGHT SNOW SHOWERS OR FLURRIES INTO EARLY
TUE AFTERNOON.
&&
.MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 426 PM EST MON DEC 9 2013
A SERIES OF TROUGHS WILL CROSS LAKE SUPERIOR THROUGH THE UPCOMING
WEEK AND BRING MULTIPLE CHANCES FOR GALES. THE FIRST TROUGH MOVING
THROUGH LATE THIS AFTERNOON WILL BRING WRLY GALES OF
35 TO 40 KNOTS ACROSS LAKE SUPERIOR LATE THIS AFTERNOON AND EVENING.
AFTER A DECREASE TO 20 TO 30 KNOT SOUTHWEST WINDS TUESDAY
MORNING...ANOTHER LOW PRESSURE WILL TRACK EASTWARD ACROSS LAKE
SUPERIOR ON TUESDAY AND COULD PRODUCE GALE FORCE WIND GUSTS TO 35
KNOTS BEHIND IT TUESDAY AFTERNOON AND EVENING. THE WESTERLY WINDS
WILL WEAKEN SLIGHTLY TO 20 TO 30 KNOTS FROM LATE TUESDAY NIGHT INTO
THURSDAY AS A WEAK RIDGE EXTENDING FROM HIGH PRESSURE IN THE CENTRAL
PLAINS SLOWLY BUILDS INTO THE AREA. CONTINUED MODERATE TO HEAVY
FREEZING SPRAY WILL BE POSSIBLE THROUGHOUT THE PERIOD WITH SEVERAL
PUSHES OF ARCTIC AIR ACROSS THE LAKE. ANOTHER WEAK LOW PRESSURE
SYSTEM WILL MOVE SOUTHEASTWARD ACROSS LAKE SUPERIOR THURSDAY NIGHT
INTO FRIDAY...BUT WINDS SHOULD REMAIN UNDER 20 KNOTS THROUGH
SATURDAY BEHIND THIS SYSTEM.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
LAKE EFFECT SNOW ADVISORY FROM 11 AM THIS MORNING TO MIDNIGHT
EST WEDNESDAY NIGHT FOR MIZ002-003.
LAKE EFFECT SNOW ADVISORY FROM 10 AM THIS MORNING TO 7 AM EST
WEDNESDAY FOR MIZ001.
LAKE EFFECT SNOW ADVISORY FROM 1 PM THIS AFTERNOON TO 5 PM EST
WEDNESDAY FOR MIZ004-084.
LAKE EFFECT SNOW ADVISORY FROM NOON TODAY TO 11 AM CST WEDNESDAY
FOR MIZ009.
LAKE EFFECT SNOW WARNING FROM 7 PM THIS EVENING TO 7 AM EST
THURSDAY FOR MIZ007.
LAKE EFFECT SNOW ADVISORY FROM 7 PM THIS EVENING TO MIDNIGHT EST
WEDNESDAY NIGHT FOR MIZ006.
LAKE SUPERIOR...
HEAVY FREEZING SPRAY WARNING UNTIL 10 AM EST THIS MORNING FOR
LSZ245-248>251-265>267.
GALE WARNING FROM 6 PM THIS EVENING TO MIDNIGHT EST TONIGHT FOR
LSZ266.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...JLB
LONG TERM...KLUBER
AVIATION...07
MARINE...JLB
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
1244 AM EST TUE DEC 10 2013
.SHORT TERM...(THIS EVENING THROUGH TUESDAY)
ISSUED AT 426 PM EST MON DEC 9 2013
WV IMAGERY AND RUC ANALYSIS INDICATED A BROAD TROUGH ACROSS NOAM.
ONE SHORTWAVE TROUGH EXTENDED FROM NW ONTARIO THROUGH WRN LAKE
SUPERIOR WHILE ANOTHER UPSTREAM SHRTWV WAS MOVING FROM SE SASK
TOWARD THE NRN PLAINS. AT THE SFC...A WEAK RIDGE OVER WRN MN
SEPARATED LOWS NE OF LAKE SUPERIOR AND OVER NE MONTANA. WSW WINDS
ACROSS WRN LAKE SUPERIOR WERE SLOWLY VEERING AS THE SHRTWV ADVANCES
THROUGH THE AREA. THE INITIAL DOMINANT BAND THROUGH THE NRN KEWEENAW
EARLY THIS AFTERNOON HAD LIFTED BACK TO THE NORTH.
HOWEVER...MULTIPLE WIND PARALLEL BANDS INTO THE NRN HALF OF THE
KEWEENAW HAVE INTENSIFIED THIS AFTERNOON...AIDED BY THE SHRTWV WHICH
HAS BOOSTED INVERSION HEIGHTS TO AROUND 9K FT AS 850 MB TEMPS DROP
INTO THE -18C TO -21C RANGE.
TONIGHT...
THE HIGH RES MODELS WERE IN GOOD AGREEMENT AND SUPPORT
UPSTREAM TRENDS OF LOW LEVEL WINDS VEERING THIS EVENING WHICH SHOULD
PUSH HEAVY LES BANDS OVER THE KEWEENAW GRADUALLY TO THE SOUTH.
HOWEVER...THE SRN EXTENT OF THE LES IS EXPECTED TO REMAIN MAINLY
NORTH OF M-38. SLR VALUES MAY BE LIMITED BY THE VERY COLD INCOMING
ARCTIC AIRMASS WHICH WILL KEEP THE DGZ BELOW 2K FT. GIVEN THE
FAVORABLE LOW LEVEL CONV PERSISTING THROUGH MUCH OF THE EVENING
BEFORE WINDS BACK AHEAD OF THE NEXT SHORTWAVE...ADDITIONAL
ACCUMULATIONS IN THE 3 TO 6 INCH RANGE ARE LIKELY. BY 12Z...EXPECT
THAT THE HEAVIER LES SHOULD LIFT TOWARD EAGLE RIVER AND COPPER
HARBOR BEFORE MOVING OFFHSORE TUE MORNING. STRONG WRLY GUSTING TO 35
MPH WILL ALSO CAUSE SIGNIFICANT BLOWING AND DRIFTING IN OPEN AREAS
WITH VSBY AOB 1/4SM IN THE HEAVIER LES BANDS BEFORE TAPER OFF AFTER
03Z/TUE.
TEMPERATURES DROPPING INTO THE ZERO TO 10 BELOW RANGE WITH WINDS OF
10 TO 15 MPH MAY DROP WIND CHILL VALUES TO 15 BELOW TO 25 BELOW THIS
EVENING. HOWEVER...WINDS ARE EXPECTED TO DIMINISH TO 7 MPH OR LESS
OVER THE COLDER INLAND AREAS...KEEPING WIND CHILLS FROM REACHING
ADVISORY THRESHOLD. IN ADDITION...CLOUDS WILL THICKEN LATE AS THE
SHRTWV APPROACHES BRINGING SLOWLY CLIMBING TEMPS LATE.
TUESDAY...
THE SASK SHRTWV WILL MOVE THROUGH THE REGION WITH MODERATE TO STRONG
700-300 MB QVECTOR CONV. EVEN THOUGH THE STRONGEST FORCING IS
EXPECTED JUST TO THE SOUTH OF UPPER MICHIGAN...IT SHOULD STILL BE
STRONG ENOUGH OVER UPPER MI TO SQUEEZE OUT SOME LIGHT SNOW WITH A
FEW HUNDREDTHS QPF IN THE VERY DRY AIRMASS. OVERALL ACCUMULATIONS
SHOULD REMAIN BELOW A HALF INCH BUT SHOULD BE WIDESPREAD ENOUGH TO
INCLUDE LIKELY POPS. VEERING WINDS IN THE WAKE OF THE SHRTWV SHOULD
BRING ANOTHER STRONG AREA OF LOW LEVEL CONV INTO NW UPPER MI AS THE
SFC TROUGH MOVES THROUGH AROUND 18Z. ANOTHER PERIOD OF HEAVIER LES
IS EXPECTED WITH THIS FEATURE THAT COULD PRODUCE 2 TO 4 INCHES OF
SNOW. SINCE THERE IS A GAP BETWEEN THE MON NIGHT LES AND THE NEXT
BATCH THE HEADLINE WAS NOT EXTENDED AT THIS TIME.
.LONG TERM...(TUESDAY NIGHT THROUGH MONDAY)
ISSUED AT 416 PM EST MON DEC 9 2013
COLD TEMPERATURES AND LAKE EFFECT SNOW WILL DOMINATE MUCH OF THE
LONG TERM FORECAST.
A SHORTWAVE AND WEAK LOW PRESSURE SYSTEM SLIDING ACROSS NORTHERN
WISCONSIN AND SOUTHERN UPPER MICHIGAN TONIGHT INTO TUESDAY MORNING
WILL PROVIDE A REINFORCING SHOT OF COLD AIR TO THE AREA FOR TUESDAY
NIGHT INTO WEDNESDAY. MEANWHILE...HIGH PRESSURE WILL BEGIN TO BUILD
INTO THE NORTHERN PLAINS BEFORE SINKING SOUTHEAST INTO THE MID
MISSISSIPPI VALLEY FOR WEDNESDAY NIGHT. MODELS ARE FAIRLY
CONSISTENT ON A SURFACE TROUGH LINGERING OVER CENTRAL/EASTERN LAKE
SUPERIOR ON THE BACK SIDE OF THE LOW TUESDAY EVENING AND THEN
SHIFTING SOUTHEAST WEDNESDAY MORNING. THIS LINGERING TROUGH WILL
LIKELY LEAD TO A LAKE INDUCED LOW DEVELOPING OVER THE FAR EASTERN
LAKE WEDNESDAY NIGHT AND REMAINING INTO THURSDAY AS A HIGH
PRESSURE RIDGE MOVES OVER SOUTHERN UPPER MICHIGAN.
OVERALL...CONDITIONS CONTINUE TO BE VERY FAVORABLE FOR LAKE EFFECT
SNOWFALL INTO THURSDAY...WITH 850MB TEMPS FALLING FROM AROUND -21C
AT 00Z WEDNESDAY TO -24C ON WEDNESDAY AFTERNOON. THIS STRONG OVER
LAKE INSTABILITY (LAKE TEMPS AROUND 2-3C) WILL LEAD TO FAIRLY HIGH
EQUILIBRIUM LEVELS (12/15KFT WEST/EAST) AND LAKE INDUCED CAPE
VALUES EXCEEDING 800-1000J/KG FOR TUESDAY NIGHT INTO WEDNESDAY. LES
WILL BE AIDED ON TUESDAY NIGHT BY LINGERING MOISTURE FROM THE
CLIPPER SYSTEM...ALLOWING THE STRONGER BANDS TO REALIZE THE HIGHER
INVERSION HEIGHTS. BUT AS THAT DEEPER MOISTURE DEPARTS THROUGH THE
NIGHT AND INTO WEDNESDAY MORNING...EXPECT A TRANSITION TO PURE LAKE
EFFECT AND THE LOSS OF THE DEEPER MOISTURE MAY LIMIT THE WEAKER
BANDS FROM REACHING THE HIGHER INVERSION HEIGHTS. LAKE EFFECT SNOW
PARAMETER REALLY HIGHLIGHTS LUCE COUNTY FOR TUESDAY NIGHT INTO
WEDNESDAY MORNING...BEFORE VALUES BEGIN TO FALL TO MORE MODERATE
LAKE EFFECT VALUES DURING THE DAY AS THE 850MB TEMPERATURES COOL.
THE REST OF THE AREA LOOKS TO SEE LOW END MODERATE VALUES DUE TO THE
AMOUNT OF COLD AIR. AS FOR SNOW RATIOS...HAVE GENERALLY KEPT VALUES
AROUND 20-1 AT THIS POINT...SINCE MUCH OF THE FORCING WILL BE AT
THE HIGH END OR ABOVE THE DGZ. THINK THE HIGHEST RATIOS WILL BE
INITIALLY TUESDAY NIGHT BEFORE THE COLDER AIR ARRIVES AND SHOVES
THE DGZ TOWARDS THE SURFACE. THOSE HIGHER RATIOS MAY BE LIMITED
SOMEWHAT BY STRONGER WINDS RIGHT BEHIND THE FRONT LEADING TO
FRACTURING OF THE DENDRITES TO GO ALONG WITH MAINLY COLUMNS. BUT
THOSE WINDS SHOULD WEAKEN SLIGHTLY INTO WEDNESDAY AND ALLOW THE
LIMITED DENDRITES TO REMAIN TOGETHER.
WITH CONDITIONS APPEARING GOOD FOR LES...WINDS WILL DETERMINE THE
BAND PLACEMENT. EXPECT THE LAKE EFFECT TO BE IN THE WESTERLY FLOW
AREAS TO START THE LONG TERM PERIOD...BUT AS THE SURFACE TROUGH
DIVES SOUTHEAST...EXPECT BANDS TO SHIFT SOUTH AND SETUP IN THE MORE
WEST-NORTHWEST TO NORTHWEST WIND LOCATIONS BY WEDNESDAY MORNING.
EXPECT THE HEAVIEST SNOW OVER NORTHERN LUCE COUNTY WHERE THERE WILL
BE INCREASED CONVERGENCE FROM THE TROUGH AND HAVE THE LONGEST FETCH
ACROSS THE LAKE. SOME DIFFERENCES IN THE TIMING THAT THE DOMINATE
BAND MOVES SOUTH INTO NORTHERN LUCE COUNTY...BUT LOOKS TO BE
THROUGH THE EVENING HOURS AND THEN REMAINING THROUGH MUCH OF
WEDNESDAY AND WEDNESDAY NIGHT BEFORE FINALLY SHIFTING NORTH ON
THURSDAY DUE TO A RIDGE MOVING INTO THE SOUTHERN U.P. WITH THE
POTENTIAL FOR HEAVY SNOW AND A PROLONGED EVENT (CURRENT FORECAST OF
1-2FT IN FAR NE LUCE COUNTY BY THURSDAY MORNING)...OPTED TO ISSUE A
LAKE EFFECT SNOW WATCH FOR LUCE COUNTY. ALGER COUNTY IS A LITTLE
MORE UNCERTAIN...AS IT DEPENDS ON HOW FAR SOUTHWEST THE BAND SINKS.
BEST OPPORTUNITY WOULD BE NEAR GRAND MARAIS. NAM IS MOST AGGRESSIVE
WITH THE SOUTHWEST PUSH...WHILE MOST OF THE OTHER MODELS KEEP WINDS
OUT OF THE WNW TO WESTERLY DIRECTION. THUS...HAVE LEFT THEM OUT OF
ANY PRODUCTS AT THIS TIME AND HOPEFULLY WE/LL BE ABLE TO PIN DOWN
THE SOUTHWEST EXTENT IN THE NEXT 24HRS.
FARTHER WEST...EXPECT THE HEAVIEST SNOW IN THE WNW FAVORED AREAS
FROM ONTONAGON THROUGH THE KEWEENAW. WITH HE SURFACE TROUGH LIKELY
SETUP ACROSS ONTONAGON COUNTY...WOULD EXPECT THERE TO BE SOME SORT
OF DOMINATE BAND AND THE HIGHEST SNOWFALL AMOUNTS THERE. AT THIS
POINT...HAVE AMOUNTS AN INCH OR TWO UNDER WARNING CRITERIA AND WILL
NOT ISSUE A WATCH. SHOULD BE A SOLID ADVISORY AND THERE IS THE
POTENTIAL FOR SOME LOCATIONS TO REACH WARNING AMOUNTS.
OTHERWISE...EXPECT GENERAL MODERATE LAKE EFFECT SNOW NORTH OF THE
TROUGH OVER THE KEWEENAW WITH ADVISORY CRITERIA ACCUMULATIONS. SINCE
THERE IS A WARNING OUT FOR THOSE AREAS...WILL HOLD OFF NOW AND
LET MID SHIFT PUT UP ADVISORIES ALL AT ONCE.
WITH THE HIGH MOVING INTO THE MID MISSISSIPPI VALLEY AND A RIDGE
SLIDING INTO SOUTHERN UPPER MICHIGAN LATE WEDNESDAY AFTERNOON
AND THROUGH THE NIGHT...EXPECT WINDS TO BACK TO MORE OF A WESTERLY
(OR EVEN SOUTHWESTERLY DIRECTION OVER WESTERN LAKE SUPERIOR). THIS
WILL PUSH THE LAKE EFFECT SNOW BACK TO THE NORTH THROUGH THE NIGHT
AND INTO THURSDAY. THE FOCUS WILL REMAIN OVER THE KEWEENAW AND THE
FAR NORTHEAST PART OF LUCE COUNTY DURING THAT TIME. INVERSION
HEIGHTS DO LOOK TO LOWER DURING THIS PERIOD TO 5-7KFT...SO
WOULD EXPECT THE INTENSITY AND AMOUNTS TO DIMINISH AS THE DGZ
LOWERS TO THE SURFACE. FINALLY...ANOTHER WEAK CLIPPER LOOKS TO
MOVE THROUGH LATE WEDNESDAY NIGHT INTO THURSDAY MORNING BUT WILL
LIKELY BE SOUTH THAN THE ONE TONIGHT AND MOVE THROUGH
CENTRAL/SOUTHERN WISCONSIN.
IN ADDITION TO THE LAKE EFFECT SNOW...COLD TEMPERATURES WILL REMAIN
OVER THE AREA THROUGH THURSDAY...WHICH WILL LEAD TO SOME CONCERNS
FOR WIND CHILL ADVISORIES ON TUESDAY/WEDNESDAY NIGHT. OVERNIGHT
LOWS WILL BE IN THE SINGLE DIGITS BELOW ZERO ON TUESDAY NIGHT AND
THEN POTENTIALLY 10 DEGREES COLDER ON WEDNESDAY NIGHT. THERE IS
SOME CONCERN FOR CLOUDS AHEAD OF THE CLIPPER SYSTEM ON WEDNESDAY
NIGHT...WHICH COULD LEAD TO SOME RISING TEMPERATURES TOWARDS
MORNING. WIND CHILLS WILL DEPEND ON HOW MUCH DECOUPLING WILL OCCUR
AND TUESDAY NIGHT WILL LIKELY SEE WINDS STAYING UP MORE WITH THE
TIGHT GRADIENT BETWEEN THE HIGH MOVING INTO THE NORTHERN PLAINS AND
THE TROUGH OVER EASTERN LAKE SUPERIOR. THIS WILL PRODUCE
WIND CHILL VALUES IN THE -20S OVER THE INTERIOR WEST AND A
DECENT CHANCE OF A WIND CHILL ADVISORY. ON WEDNESDAY NIGHT THE
SURFACE RIDGE WILL BE MOVING IN AND LEADING TO LIGHT WINDS
OVERNIGHT. THESE LIGHT WINDS WILL ALLOW FOR LOWER TEMPS (IF THE
CLOUDS STAY TO THE SOUTHWEST) BUT ALSO LIMIT WIND CHILL VALUES...BUT
STILL EXPECT THEM IN THE -25 TO -34 DEGREE F RANGE.
FOR FRIDAY TO NEXT MONDAY...THE GENERAL TREND IN THE MODELS IS FOR
THE UPPER TROUGH TO SHIFT EAST THURSDAY NIGHT AND FRIDAY...LEADING
TO SOME MODERATION OF THE COLDER AIR AS THE FLOW ALOFT BECOMES
WESTERLY. THEN...AS THE SOUTHERN STREAM TROUGH MOVES INTO THE
SOUTHEAST CONUS THIS WEEKEND...ANOTHER STRONG SHORTWAVE WILL DIVE
SOUTHEAST IN THE NORTHERN STREAM AND LEAD TO ANOTHER PERIOD OF COLD
WEATHER FOR SUNDAY AND THE START OF NEXT WEEK. MODELS STILL VARY ON
THE EXACT SOLUTION AND TIMING AS THE DISTURBANCES PHASE OVER THE
EASTERN CONUS...BUT THE GENERAL IDEA IS A SURFACE TROUGH
SETTING UP OVER THE UPPER GREAT LAKES (STRETCHING NORTHWEST
FROM THE LOW MOVING UP THE EAST COAST) FOR MUCH OF THE WEEKEND
BEFORE DIVING SOUTHEAST ON SUNDAY NIGHT AND MONDAY WITH THE
NORTHERN STREAM SHORTWAVE. MOISTURE ASSOCIATED WITH THE TROUGH...
850MB TEMPS AROUND -22C AND LIKELY LIGHT NORTHERLY WINDS
SUPPORTS HAVING SLIGHT/CHANCE POPS OVER MUCH OF THE
AREA...ESPECIALLY IN THE NORTH TO NORTHEAST FAVORED LOCATIONS NEAR
LAKE SUPERIOR. THIS NORTHERLY FLOW WILL LIKELY LEAD TO SOME LES FOR
AREAS THAT HAVE BEEN MISSED BY THE LES AT THE END OF LAST WEEK AND
THIS WEEK. SINCE THERE IS CONSISTENCY IN THE MODELS THIS
WEEKEND...WILL TREND POPS UP IN THE NORTHERLY WIND AREAS FRIDAY
NIGHT INTO SUNDAY AND BEGIN TO HIGHLIGHT IN THE HWO/EHWO.
HIGH PRESSURE WILL LIKELY BUILD INTO THE UPPER GREAT LAKES ON
MONDAY AFTERNOON...ALTHOUGH THERE ARE HINTS OF ANOTHER SHORTWAVE
DIVING INTO THE UPPER MISSISSIPPI VALLEY FOR MONDAY NIGHT.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z TUESDAY NIGHT)
ISSUED AT 1239 AM EST TUE DEC 10 2013
KIWD...WILL BE VFR THROUGH TONIGHT. MVFR CONDITIONS IN LIGHT SNOW
RETURN TUE MORNING WITH APPROACH OF NEXT DISTURBANCE FROM THE
NORTHERN PLAINS AND THIS REMAINS THROUGH THE REST OF THE FORECAST
PERIOD.
KCMX...IFR CONDITIONS WITH LIGHT LAKE EFFECT SNOW WILL IMPROVE TO
MVFR LATER TONIGHT AS THE WIND BACKS TO THE SW AND THE HEAVIER LES
BANDS SHIFT NORTH OF THE AREA. AS WINDS GO BACK WEST BY TUE
AFTERNOON...CONDITIONS WILL DETERIORATE AGAIN TO VLIFR WITH BLOWING
SNOW AND HEAVIER LAKE EFFECT SNOW BANDS AFFECTING THE TAF SITE
THROUGH TUE EVENING.
KSAW...VFR CONDITIONS WILL CONTINUE THROUGH THE FORECAST PERIOD. THE
NEXT SHORTWAVE TROUGH MOVING INTO THE AREA TUE MORNING WILL BRING
ANOTHER PERIOD WITH SOME LIGHT SNOW SHOWERS OR FLURRIES INTO EARLY
TUE AFTERNOON.
&&
.MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 426 PM EST MON DEC 9 2013
A SERIES OF TROUGHS WILL CROSS LAKE SUPERIOR THROUGH THE UPCOMING
WEEK AND BRING MULTIPLE CHANCES FOR GALES. THE FIRST TROUGH MOVING
THROUGH LATE THIS AFTERNOON WILL BRING WRLY GALES OF
35 TO 40 KNOTS ACROSS LAKE SUPERIOR LATE THIS AFTERNOON AND EVENING.
AFTER A DECREASE TO 20 TO 30 KNOT SOUTHWEST WINDS TUESDAY
MORNING...ANOTHER LOW PRESSURE WILL TRACK EASTWARD ACROSS LAKE
SUPERIOR ON TUESDAY AND COULD PRODUCE GALE FORCE WIND GUSTS TO 35
KNOTS BEHIND IT TUESDAY AFTERNOON AND EVENING. THE WESTERLY WINDS
WILL WEAKEN SLIGHTLY TO 20 TO 30 KNOTS FROM LATE TUESDAY NIGHT INTO
THURSDAY AS A WEAK RIDGE EXTENDING FROM HIGH PRESSURE IN THE CENTRAL
PLAINS SLOWLY BUILDS INTO THE AREA. CONTINUED MODERATE TO HEAVY
FREEZING SPRAY WILL BE POSSIBLE THROUGHOUT THE PERIOD WITH SEVERAL
PUSHES OF ARCTIC AIR ACROSS THE LAKE. ANOTHER WEAK LOW PRESSURE
SYSTEM WILL MOVE SOUTHEASTWARD ACROSS LAKE SUPERIOR THURSDAY NIGHT
INTO FRIDAY...BUT WINDS SHOULD REMAIN UNDER 20 KNOTS THROUGH
SATURDAY BEHIND THIS SYSTEM.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
LAKE EFFECT SNOW WARNING UNTIL 7 AM EST THIS MORNING FOR MIZ001-
003.
LAKE EFFECT SNOW WATCH FROM THIS EVENING THROUGH THURSDAY
MORNING FOR MIZ007.
LAKE SUPERIOR...
HEAVY FREEZING SPRAY WARNING UNTIL 10 AM EST THIS MORNING FOR
LSZ245-248>251-265>267.
GALE WARNING UNTIL 1 AM EST EARLY THIS MORNING FOR LSZ244-245-
248>251-264>267.
HEAVY FREEZING SPRAY WARNING UNTIL 7 AM EST /6 AM CST/ THIS
MORNING FOR LSZ162-240>244-263-264.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...JLB
LONG TERM...SRF
AVIATION...07
MARINE...JLB
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
1153 PM EST MON DEC 9 2013
.SHORT TERM...(THIS EVENING THROUGH TUESDAY)
ISSUED AT 426 PM EST MON DEC 9 2013
WV IMAGERY AND RUC ANALYSIS INDICATED A BROAD TROUGH ACROSS NOAM.
ONE SHORTWAVE TROUGH EXTENDED FROM NW ONTARIO THROUGH WRN LAKE
SUPERIOR WHILE ANOTHER UPSTREAM SHRTWV WAS MOVING FROM SE SASK
TOWARD THE NRN PLAINS. AT THE SFC...A WEAK RIDGE OVER WRN MN
SEPARATED LOWS NE OF LAKE SUPERIOR AND OVER NE MONTANA. WSW WINDS
ACROSS WRN LAKE SUPERIOR WERE SLOWLY VEERING AS THE SHRTWV ADVANCES
THROUGH THE AREA. THE INITIAL DOMINANT BAND THROUGH THE NRN KEWEENAW
EARLY THIS AFTERNOON HAD LIFTED BACK TO THE NORTH.
HOWEVER...MULTIPLE WIND PARALLEL BANDS INTO THE NRN HALF OF THE
KEWEENAW HAVE INTENSIFIED THIS AFTERNOON...AIDED BY THE SHRTWV WHICH
HAS BOOSTED INVERSION HEIGHTS TO AROUND 9K FT AS 850 MB TEMPS DROP
INTO THE -18C TO -21C RANGE.
TONIGHT...
THE HIGH RES MODELS WERE IN GOOD AGREEMENT AND SUPPORT
UPSTREAM TRENDS OF LOW LEVEL WINDS VEERING THIS EVENING WHICH SHOULD
PUSH HEAVY LES BANDS OVER THE KEWEENAW GRADUALLY TO THE SOUTH.
HOWEVER...THE SRN EXTENT OF THE LES IS EXPECTED TO REMAIN MAINLY
NORTH OF M-38. SLR VALUES MAY BE LIMITED BY THE VERY COLD INCOMING
ARCTIC AIRMASS WHICH WILL KEEP THE DGZ BELOW 2K FT. GIVEN THE
FAVORABLE LOW LEVEL CONV PERSISTING THROUGH MUCH OF THE EVENING
BEFORE WINDS BACK AHEAD OF THE NEXT SHORTWAVE...ADDITIONAL
ACCUMULATIONS IN THE 3 TO 6 INCH RANGE ARE LIKELY. BY 12Z...EXPECT
THAT THE HEAVIER LES SHOULD LIFT TOWARD EAGLE RIVER AND COPPER
HARBOR BEFORE MOVING OFFHSORE TUE MORNING. STRONG WRLY GUSTING TO 35
MPH WILL ALSO CAUSE SIGNIFICANT BLOWING AND DRIFTING IN OPEN AREAS
WITH VSBY AOB 1/4SM IN THE HEAVIER LES BANDS BEFORE TAPER OFF AFTER
03Z/TUE.
TEMPERATURES DROPPING INTO THE ZERO TO 10 BELOW RANGE WITH WINDS OF
10 TO 15 MPH MAY DROP WIND CHILL VALUES TO 15 BELOW TO 25 BELOW THIS
EVENING. HOWEVER...WINDS ARE EXPECTED TO DIMINISH TO 7 MPH OR LESS
OVER THE COLDER INLAND AREAS...KEEPING WIND CHILLS FROM REACHING
ADVISORY THRESHOLD. IN ADDITION...CLOUDS WILL THICKEN LATE AS THE
SHRTWV APPROACHES BRINGING SLOWLY CLIMBING TEMPS LATE.
TUESDAY...
THE SASK SHRTWV WILL MOVE THROUGH THE REGION WITH MODERATE TO STRONG
700-300 MB QVECTOR CONV. EVEN THOUGH THE STRONGEST FORCING IS
EXPECTED JUST TO THE SOUTH OF UPPER MICHIGAN...IT SHOULD STILL BE
STRONG ENOUGH OVER UPPER MI TO SQUEEZE OUT SOME LIGHT SNOW WITH A
FEW HUNDREDTHS QPF IN THE VERY DRY AIRMASS. OVERALL ACCUMULATIONS
SHOULD REMAIN BELOW A HALF INCH BUT SHOULD BE WIDESPREAD ENOUGH TO
INCLUDE LIKELY POPS. VEERING WINDS IN THE WAKE OF THE SHRTWV SHOULD
BRING ANOTHER STRONG AREA OF LOW LEVEL CONV INTO NW UPPER MI AS THE
SFC TROUGH MOVES THROUGH AROUND 18Z. ANOTHER PERIOD OF HEAVIER LES
IS EXPECTED WITH THIS FEATURE THAT COULD PRODUCE 2 TO 4 INCHES OF
SNOW. SINCE THERE IS A GAP BETWEEN THE MON NIGHT LES AND THE NEXT
BATCH THE HEADLINE WAS NOT EXTENDED AT THIS TIME.
.LONG TERM...(TUESDAY NIGHT THROUGH MONDAY)
ISSUED AT 416 PM EST MON DEC 9 2013
COLD TEMPERATURES AND LAKE EFFECT SNOW WILL DOMINATE MUCH OF THE
LONG TERM FORECAST.
A SHORTWAVE AND WEAK LOW PRESSURE SYSTEM SLIDING ACROSS NORTHERN
WISCONSIN AND SOUTHERN UPPER MICHIGAN TONIGHT INTO TUESDAY MORNING
WILL PROVIDE A REINFORCING SHOT OF COLD AIR TO THE AREA FOR TUESDAY
NIGHT INTO WEDNESDAY. MEANWHILE...HIGH PRESSURE WILL BEGIN TO BUILD
INTO THE NORTHERN PLAINS BEFORE SINKING SOUTHEAST INTO THE MID
MISSISSIPPI VALLEY FOR WEDNESDAY NIGHT. MODELS ARE FAIRLY
CONSISTENT ON A SURFACE TROUGH LINGERING OVER CENTRAL/EASTERN LAKE
SUPERIOR ON THE BACK SIDE OF THE LOW TUESDAY EVENING AND THEN
SHIFTING SOUTHEAST WEDNESDAY MORNING. THIS LINGERING TROUGH WILL
LIKELY LEAD TO A LAKE INDUCED LOW DEVELOPING OVER THE FAR EASTERN
LAKE WEDNESDAY NIGHT AND REMAINING INTO THURSDAY AS A HIGH
PRESSURE RIDGE MOVES OVER SOUTHERN UPPER MICHIGAN.
OVERALL...CONDITIONS CONTINUE TO BE VERY FAVORABLE FOR LAKE EFFECT
SNOWFALL INTO THURSDAY...WITH 850MB TEMPS FALLING FROM AROUND -21C
AT 00Z WEDNESDAY TO -24C ON WEDNESDAY AFTERNOON. THIS STRONG OVER
LAKE INSTABILITY (LAKE TEMPS AROUND 2-3C) WILL LEAD TO FAIRLY HIGH
EQUILIBRIUM LEVELS (12/15KFT WEST/EAST) AND LAKE INDUCED CAPE
VALUES EXCEEDING 800-1000J/KG FOR TUESDAY NIGHT INTO WEDNESDAY. LES
WILL BE AIDED ON TUESDAY NIGHT BY LINGERING MOISTURE FROM THE
CLIPPER SYSTEM...ALLOWING THE STRONGER BANDS TO REALIZE THE HIGHER
INVERSION HEIGHTS. BUT AS THAT DEEPER MOISTURE DEPARTS THROUGH THE
NIGHT AND INTO WEDNESDAY MORNING...EXPECT A TRANSITION TO PURE LAKE
EFFECT AND THE LOSS OF THE DEEPER MOISTURE MAY LIMIT THE WEAKER
BANDS FROM REACHING THE HIGHER INVERSION HEIGHTS. LAKE EFFECT SNOW
PARAMETER REALLY HIGHLIGHTS LUCE COUNTY FOR TUESDAY NIGHT INTO
WEDNESDAY MORNING...BEFORE VALUES BEGIN TO FALL TO MORE MODERATE
LAKE EFFECT VALUES DURING THE DAY AS THE 850MB TEMPERATURES COOL.
THE REST OF THE AREA LOOKS TO SEE LOW END MODERATE VALUES DUE TO THE
AMOUNT OF COLD AIR. AS FOR SNOW RATIOS...HAVE GENERALLY KEPT VALUES
AROUND 20-1 AT THIS POINT...SINCE MUCH OF THE FORCING WILL BE AT
THE HIGH END OR ABOVE THE DGZ. THINK THE HIGHEST RATIOS WILL BE
INITIALLY TUESDAY NIGHT BEFORE THE COLDER AIR ARRIVES AND SHOVES
THE DGZ TOWARDS THE SURFACE. THOSE HIGHER RATIOS MAY BE LIMITED
SOMEWHAT BY STRONGER WINDS RIGHT BEHIND THE FRONT LEADING TO
FRACTURING OF THE DENDRITES TO GO ALONG WITH MAINLY COLUMNS. BUT
THOSE WINDS SHOULD WEAKEN SLIGHTLY INTO WEDNESDAY AND ALLOW THE
LIMITED DENDRITES TO REMAIN TOGETHER.
WITH CONDITIONS APPEARING GOOD FOR LES...WINDS WILL DETERMINE THE
BAND PLACEMENT. EXPECT THE LAKE EFFECT TO BE IN THE WESTERLY FLOW
AREAS TO START THE LONG TERM PERIOD...BUT AS THE SURFACE TROUGH
DIVES SOUTHEAST...EXPECT BANDS TO SHIFT SOUTH AND SETUP IN THE MORE
WEST-NORTHWEST TO NORTHWEST WIND LOCATIONS BY WEDNESDAY MORNING.
EXPECT THE HEAVIEST SNOW OVER NORTHERN LUCE COUNTY WHERE THERE WILL
BE INCREASED CONVERGENCE FROM THE TROUGH AND HAVE THE LONGEST FETCH
ACROSS THE LAKE. SOME DIFFERENCES IN THE TIMING THAT THE DOMINATE
BAND MOVES SOUTH INTO NORTHERN LUCE COUNTY...BUT LOOKS TO BE
THROUGH THE EVENING HOURS AND THEN REMAINING THROUGH MUCH OF
WEDNESDAY AND WEDNESDAY NIGHT BEFORE FINALLY SHIFTING NORTH ON
THURSDAY DUE TO A RIDGE MOVING INTO THE SOUTHERN U.P. WITH THE
POTENTIAL FOR HEAVY SNOW AND A PROLONGED EVENT (CURRENT FORECAST OF
1-2FT IN FAR NE LUCE COUNTY BY THURSDAY MORNING)...OPTED TO ISSUE A
LAKE EFFECT SNOW WATCH FOR LUCE COUNTY. ALGER COUNTY IS A LITTLE
MORE UNCERTAIN...AS IT DEPENDS ON HOW FAR SOUTHWEST THE BAND SINKS.
BEST OPPORTUNITY WOULD BE NEAR GRAND MARAIS. NAM IS MOST AGGRESSIVE
WITH THE SOUTHWEST PUSH...WHILE MOST OF THE OTHER MODELS KEEP WINDS
OUT OF THE WNW TO WESTERLY DIRECTION. THUS...HAVE LEFT THEM OUT OF
ANY PRODUCTS AT THIS TIME AND HOPEFULLY WE/LL BE ABLE TO PIN DOWN
THE SOUTHWEST EXTENT IN THE NEXT 24HRS.
FARTHER WEST...EXPECT THE HEAVIEST SNOW IN THE WNW FAVORED AREAS
FROM ONTONAGON THROUGH THE KEWEENAW. WITH HE SURFACE TROUGH LIKELY
SETUP ACROSS ONTONAGON COUNTY...WOULD EXPECT THERE TO BE SOME SORT
OF DOMINATE BAND AND THE HIGHEST SNOWFALL AMOUNTS THERE. AT THIS
POINT...HAVE AMOUNTS AN INCH OR TWO UNDER WARNING CRITERIA AND WILL
NOT ISSUE A WATCH. SHOULD BE A SOLID ADVISORY AND THERE IS THE
POTENTIAL FOR SOME LOCATIONS TO REACH WARNING AMOUNTS.
OTHERWISE...EXPECT GENERAL MODERATE LAKE EFFECT SNOW NORTH OF THE
TROUGH OVER THE KEWEENAW WITH ADVISORY CRITERIA ACCUMULATIONS. SINCE
THERE IS A WARNING OUT FOR THOSE AREAS...WILL HOLD OFF NOW AND
LET MID SHIFT PUT UP ADVISORIES ALL AT ONCE.
WITH THE HIGH MOVING INTO THE MID MISSISSIPPI VALLEY AND A RIDGE
SLIDING INTO SOUTHERN UPPER MICHIGAN LATE WEDNESDAY AFTERNOON
AND THROUGH THE NIGHT...EXPECT WINDS TO BACK TO MORE OF A WESTERLY
(OR EVEN SOUTHWESTERLY DIRECTION OVER WESTERN LAKE SUPERIOR). THIS
WILL PUSH THE LAKE EFFECT SNOW BACK TO THE NORTH THROUGH THE NIGHT
AND INTO THURSDAY. THE FOCUS WILL REMAIN OVER THE KEWEENAW AND THE
FAR NORTHEAST PART OF LUCE COUNTY DURING THAT TIME. INVERSION
HEIGHTS DO LOOK TO LOWER DURING THIS PERIOD TO 5-7KFT...SO
WOULD EXPECT THE INTENSITY AND AMOUNTS TO DIMINISH AS THE DGZ
LOWERS TO THE SURFACE. FINALLY...ANOTHER WEAK CLIPPER LOOKS TO
MOVE THROUGH LATE WEDNESDAY NIGHT INTO THURSDAY MORNING BUT WILL
LIKELY BE SOUTH THAN THE ONE TONIGHT AND MOVE THROUGH
CENTRAL/SOUTHERN WISCONSIN.
IN ADDITION TO THE LAKE EFFECT SNOW...COLD TEMPERATURES WILL REMAIN
OVER THE AREA THROUGH THURSDAY...WHICH WILL LEAD TO SOME CONCERNS
FOR WIND CHILL ADVISORIES ON TUESDAY/WEDNESDAY NIGHT. OVERNIGHT
LOWS WILL BE IN THE SINGLE DIGITS BELOW ZERO ON TUESDAY NIGHT AND
THEN POTENTIALLY 10 DEGREES COLDER ON WEDNESDAY NIGHT. THERE IS
SOME CONCERN FOR CLOUDS AHEAD OF THE CLIPPER SYSTEM ON WEDNESDAY
NIGHT...WHICH COULD LEAD TO SOME RISING TEMPERATURES TOWARDS
MORNING. WIND CHILLS WILL DEPEND ON HOW MUCH DECOUPLING WILL OCCUR
AND TUESDAY NIGHT WILL LIKELY SEE WINDS STAYING UP MORE WITH THE
TIGHT GRADIENT BETWEEN THE HIGH MOVING INTO THE NORTHERN PLAINS AND
THE TROUGH OVER EASTERN LAKE SUPERIOR. THIS WILL PRODUCE
WIND CHILL VALUES IN THE -20S OVER THE INTERIOR WEST AND A
DECENT CHANCE OF A WIND CHILL ADVISORY. ON WEDNESDAY NIGHT THE
SURFACE RIDGE WILL BE MOVING IN AND LEADING TO LIGHT WINDS
OVERNIGHT. THESE LIGHT WINDS WILL ALLOW FOR LOWER TEMPS (IF THE
CLOUDS STAY TO THE SOUTHWEST) BUT ALSO LIMIT WIND CHILL VALUES...BUT
STILL EXPECT THEM IN THE -25 TO -34 DEGREE F RANGE.
FOR FRIDAY TO NEXT MONDAY...THE GENERAL TREND IN THE MODELS IS FOR
THE UPPER TROUGH TO SHIFT EAST THURSDAY NIGHT AND FRIDAY...LEADING
TO SOME MODERATION OF THE COLDER AIR AS THE FLOW ALOFT BECOMES
WESTERLY. THEN...AS THE SOUTHERN STREAM TROUGH MOVES INTO THE
SOUTHEAST CONUS THIS WEEKEND...ANOTHER STRONG SHORTWAVE WILL DIVE
SOUTHEAST IN THE NORTHERN STREAM AND LEAD TO ANOTHER PERIOD OF COLD
WEATHER FOR SUNDAY AND THE START OF NEXT WEEK. MODELS STILL VARY ON
THE EXACT SOLUTION AND TIMING AS THE DISTURBANCES PHASE OVER THE
EASTERN CONUS...BUT THE GENERAL IDEA IS A SURFACE TROUGH
SETTING UP OVER THE UPPER GREAT LAKES (STRETCHING NORTHWEST
FROM THE LOW MOVING UP THE EAST COAST) FOR MUCH OF THE WEEKEND
BEFORE DIVING SOUTHEAST ON SUNDAY NIGHT AND MONDAY WITH THE
NORTHERN STREAM SHORTWAVE. MOISTURE ASSOCIATED WITH THE TROUGH...
850MB TEMPS AROUND -22C AND LIKELY LIGHT NORTHERLY WINDS
SUPPORTS HAVING SLIGHT/CHANCE POPS OVER MUCH OF THE
AREA...ESPECIALLY IN THE NORTH TO NORTHEAST FAVORED LOCATIONS NEAR
LAKE SUPERIOR. THIS NORTHERLY FLOW WILL LIKELY LEAD TO SOME LES FOR
AREAS THAT HAVE BEEN MISSED BY THE LES AT THE END OF LAST WEEK AND
THIS WEEK. SINCE THERE IS CONSISTENCY IN THE MODELS THIS
WEEKEND...WILL TREND POPS UP IN THE NORTHERLY WIND AREAS FRIDAY
NIGHT INTO SUNDAY AND BEGIN TO HIGHLIGHT IN THE HWO/EHWO.
HIGH PRESSURE WILL LIKELY BUILD INTO THE UPPER GREAT LAKES ON
MONDAY AFTERNOON...ALTHOUGH THERE ARE HINTS OF ANOTHER SHORTWAVE
DIVING INTO THE UPPER MISSISSIPPI VALLEY FOR MONDAY NIGHT.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z TUESDAY NIGHT)
ISSUED AT 1153 PM EST MON DEC 9 2013
KIWD...WILL BE VFR THROUGH TONIGHT. MVFR CONDITIONS IN LIGHT SNOW
RETURN TUE MORNING WITH APPROACH OF NEXT DISTURBANCE THE NORTHERN
PLAINS AND THIS REMAINS THROUGH THE REST OF THE FORECAST PERIOD.
KCMX...IFR CONDITIONS WITH LIGHT LAKE EFFECT SNOW WILL IMPROVE TO
MVFR LATER TONIGHT AS THE WIND BACKS TO THE SW AS THE HEAVIER LES
BANDS SHIFT NORTH OF THE AREA. AS WINDS GO BACK WEST BY TUE
AFTERNOON...CONDITIONS WILL DETERIORATE AGAIN TO VLIFR WITH BLOWING
SNOW AND HEAVIER LAKE EFFECT SNOW BANDS AFFECTING THE TAF SITE
THROUGH TUE EVENING.
KSAW...VFR CONDITIONS WILL CONTINUE THROUGH THE FORECAST PERIOD. THE
NEXT SHORTWAVE TROUGH MOVING INTO THE AREA TUE MORNING WILL BRING
ANOTHER PERIOD WITH SOME LIGHT SNOW SHOWERS OR FLURRIES INTO EARLY
TUE AFTERNOON.
&&
.MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 426 PM EST MON DEC 9 2013
A SERIES OF TROUGHS WILL CROSS LAKE SUPERIOR THROUGH THE UPCOMING
WEEK AND BRING MULTIPLE CHANCES FOR GALES. THE FIRST TROUGH MOVING
THROUGH LATE THIS AFTERNOON WILL BRING WRLY GALES OF
35 TO 40 KNOTS ACROSS LAKE SUPERIOR LATE THIS AFTERNOON AND EVENING.
AFTER A DECREASE TO 20 TO 30 KNOT SOUTHWEST WINDS TUESDAY
MORNING...ANOTHER LOW PRESSURE WILL TRACK EASTWARD ACROSS LAKE
SUPERIOR ON TUESDAY AND COULD PRODUCE GALE FORCE WIND GUSTS TO 35
KNOTS BEHIND IT TUESDAY AFTERNOON AND EVENING. THE WESTERLY WINDS
WILL WEAKEN SLIGHTLY TO 20 TO 30 KNOTS FROM LATE TUESDAY NIGHT INTO
THURSDAY AS A WEAK RIDGE EXTENDING FROM HIGH PRESSURE IN THE CENTRAL
PLAINS SLOWLY BUILDS INTO THE AREA. CONTINUED MODERATE TO HEAVY
FREEZING SPRAY WILL BE POSSIBLE THROUGHOUT THE PERIOD WITH SEVERAL
PUSHES OF ARCTIC AIR ACROSS THE LAKE. ANOTHER WEAK LOW PRESSURE
SYSTEM WILL MOVE SOUTHEASTWARD ACROSS LAKE SUPERIOR THURSDAY NIGHT
INTO FRIDAY...BUT WINDS SHOULD REMAIN UNDER 20 KNOTS THROUGH
SATURDAY BEHIND THIS SYSTEM.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
LAKE EFFECT SNOW WARNING UNTIL 7 AM EST TUESDAY FOR MIZ001-003.
LAKE EFFECT SNOW WATCH FROM TUESDAY EVENING THROUGH THURSDAY
MORNING FOR MIZ007.
LAKE SUPERIOR...
HEAVY FREEZING SPRAY WARNING UNTIL 10 AM EST TUESDAY FOR LSZ245-
248>251-265>267.
GALE WARNING UNTIL 1 AM EST TUESDAY FOR LSZ244-245-248>251-
264>267.
HEAVY FREEZING SPRAY WARNING UNTIL 7 AM EST /6 AM CST/ TUESDAY
FOR LSZ162-240>244-263-264.
GALE WARNING UNTIL MIDNIGHT EST TONIGHT FOR LSZ263.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...JLB
LONG TERM...SRF
AVIATION...07
MARINE...JLB
AREA FORECAST DISCUSSION
NWS BILLINGS MT
340 AM MST TUE DEC 10 2013
.SHORT TERM...VALID FOR TDY AND WED...
ALBERTA CLIPPER NUMBER TWO ARRIVES TODAY WITH A HIGHER PROBABILITY
OF MORE WIDESPREAD 1 TO 2 INCH SNOWFALL...BUT WIND ISSUES CONTINUE
BOTH AHEAD OF IT SOUTH CENTRAL...AND BEHIND IT SOUTHEAST /ALTHOUGH
WE DO NOT EXPECT THEM TO BE AS STRONG AS ON MON THERE/.
TODAY...WE UPGRADED THE LIVINGSTON AREA AND BEARTOOTH FOOTHILLS TO
A BLIZZARD WARNING OVERNIGHT GIVEN FREQUENT 70+ MPH WIND GUSTS AND
1/4SM VISIBILITY AT THE LIVINGSTON AIRPORT. SPOTTERS NEAR NYE ALSO
REPORTED MAJOR DRIFTING AND LOW VISIBILITY. THE LOW-LEVEL PRESSURE
GRADIENT SHOULD EVER-SO-SLOWLY RELAX AFTER SUNRISE AS A SHORT WAVE
IN CENTRAL CANADA HEADS SOUTHEAST...BUT THE IMPACTS WILL BE SEVERE
INTO AT LEAST THE FIRST PART OF THE MORNING...SO THE HEADLINE RUNS
UNTIL 19 UTC. THE REST OF THE WINTER WEATHER ADVISORY FOR PARTS OF
SOUTH CENTRAL MT THAT WAS ORIGINALLY SET TO EXPIRE VERY EARLY THIS
MORNING HAS ALSO BEEN EXTENDED UNTIL 19 UTC BASED ON RECENT TRENDS
IN OBSERVATIONS. SINCE WINDS HAVE TAKEN ON A GAP NATURE...THERE IS
ALSO SIGNIFICANT FLOW IN THE PARADISE VALLEY...WHERE WE DID HAVE A
REPORT OF BLOWING AND DRIFTING SNOW LATE MON EVENING. WE THEREFORE
ADDED THE PARADISE VALLEY TO A WINTER WEATHER ADVISORY TOO.
MEANWHILE...WE HOISTED YET ANOTHER WINTER WEATHER ADVISORY FOR ALL
OF SOUTHEASTERN MT FROM 15 UTC THROUGH 04 UTC. A DEEPENING SURFACE
LOW WILL DROP INTO SOUTHERN ND BY AFTERNOON...WITH INCREASING COLD
AIR ADVECTION AND NOTABLE SURFACE PRESSURE RISES IN ITS WAKE. WIND
SPEEDS ALOFT NEAR 850 HPA ARE ONLY SIMULATED TO BE NEAR 30 KT /NOT
50 KT LIKE ON MON/...BUT THE SITUATION WILL LIKELY YIELD 25 MPH OR
HIGHER GUSTS FOR AT LEAST A FEW HOURS. THAT SHOULD BE ENOUGH FOR A
ROUND OF BLOWING AND DRIFTING SNOW. ROBUST QG-FORCING WILL BRING A
SOLID ROUND OF SNOW TO SOUTHEAST MT DURING THE DAY TOO...WITH 1 TO
2 INCHES OF ACCUMULATION LIKELY. THE FALLING SNOW WILL THUS ADD TO
THE IMPACTS OF BLOWING AND DRIFTING AND ALREADY ICY ROADS...ENOUGH
TO NECESSITATE ANOTHER HEADLINE. NOTE THAT THERE IS A CHANCE MODEL
SIMULATIONS ARE UNDERESTIMATING SURFACE WIND SPEEDS IN THE WAKE OF
THE FRONT GIVEN THE EXPECTED COLD AIR ADVECTION. WE WILL THUS NEED
TO KEEP A CLOSE EYE ON TRENDS THROUGH THE DAY.
BY AFTERNOON...THE COLD FRONT TRAILING THE ALBERTA CLIPPER WILL BE
DROPPING THROUGH SOUTH CENTRAL MT...WHICH SHOULD ALLOW THE WIND TO
BECOME UPSLOPE IN TRAJECTORY. LIKELY POPS ARE THEREFORE STILL GOOD
FOR PLACES LIKE BILLINGS AND SOUTHERN BIG HORN COUNTY...WITH LIGHT
ACCUMULATIONS LIKELY BEHIND THE FRONT...ESPECIALLY IN SOUTHERN BIG
HORN COUNTY IF YOU BELIEVE RECENT RAP SIMULATIONS.
TONIGHT...FORCING WITH THE SHORT WAVE IS ALL BUT GONE BY THE EARLY
EVENING...SO WE WILL MAINLY BE LEFT WITH UPSLOPE FLOW AND RESIDUAL
CYCLONIC FLOW FOR MAKING SNOW IN SOUTH CENTRAL MT AND SOUTHEASTERN
MT...RESPECTIVELY. THE UPSLOPE WOULD HAVE THE BETTER CHANCE OF ANY
MEANINGFUL ACCUMULATIONS...ESPECIALLY IF ANY OROGRAPHIC SNOW BANDS
MANAGE TO FORM AND IMPACT PLACES LIKE BILLINGS /SOMETHING WHICH IS
NOT COMPLETELY OUT OF THE QUESTION/. EVERYTHING SETTLES DOWN BY 06
UTC THOUGH AS LOW-LEVEL GRADIENTS REVERSE AND UPSLOPE DIMINISHES.
WED...WE WILL FINALLY HAVE A RELATIVELY QUIET DAY...SAVE FOR WINDS
AROUND THE FOOTHILLS...WHICH SHOULD AGAIN REACH ADVISORY LEVELS AS
AN IDAHO FALLS TO LEWISTOWN SURFACE PRESSURE GRADIENT ON THE ORDER
OF 15 HPA DRIVES STRONG WINDS AROUND LIVINGSTON AND NYE YET AGAIN.
IF THE SNOW HAS NOT HARDENED SUFFICIENTLY FROM THE DRIFTING DURING
THE LAST TWO DAYS...A WINTER WEATHER ADVISORY WILL PROBABLY BE THE
OPERATIVE HEADLINE ONCE AGAIN WED INTO WED NIGHT. ELSEWHERE...WIND
SPEEDS MAY BE A BIT BREEZY AT TIMES THANKS TO MIXING...BUT IMPACTS
SHOULD BE MUCH LOWER THAN EARLIER DAYS. A WARMING TREND WILL BE IN
THE CARDS ALOFT...ALBEIT A SLOW ONE...BUT THE DEGREE OF WARMING AT
THE SURFACE IS A LOW-CONFIDENCE ITEM. SCHULTZ
.LONG TERM...VALID FOR THU...FRI...SAT...SUN...MON...
THURSDAY SHOULD BE THE WARMEST DAY OF THE WEEK AS A DOWNSLOPE WIND
PATTERN COMBINES WITH A WESTERLY FLOW ALOFT TO BRING GOOD MIXING
AND A FEW TEMPERATURES COULD CLIMB ABOVE FREEZING. IT WILL
CERTAINLY BE WINDY FOR THE WESTERN ZONES AND HAVE RAISED WINDS IN
THE GAP FLOW AREAS AND SUSPECT THERE MAY BE ANOTHER HIGH WIND
EVENT WHICH COULD BLOW SNOW AROUND...BUT THE TEMPERATURES ARE
EXPECTED TO BE WARMER.
COLD FRONT BACKS INTO THE CENTRAL AND EASTERN AREAS ON FRIDAY FOR
A COOL DOWN ESPECIALLY FOR SOUTHEAST MONTANA AND A RETURN OF SNOW
TO THE FORECAST. A LITTLE BIT OF MODERATION FRIDAY NIGHT AS A
DISTURBANCE BRINGS A ROUND OF PRESSURE FALLS AND THEN A STRONGER
COLD SHOT COMES ON SATURDAY. THIS SYSTEM WILL HAVE A STRONGER
CLIPPER EFFECT ACROSS SOUTHEAST MONTANA AND WILL HAVE TO WATCH FOR
A ROUND OF NORTHWEST WINDS BRINGING A BETTER CHANCE FOR
ACCUMULATING AND BLOWING SNOW.
FLOW SWITCHES FROM NORTHWESTERLY FRIDAY AND SATURDAY TO A BIT MORE
WESTERLY ON SUNDAY AND MONDAY FAVORING MODERATING TEMPERATURES AND
SHIFTING BEST CHANCES FOR PRECIPITATION AWAY FROM THE REGION AS
DOWNSLOPE BECOMES A STRONGER FACTOR. FLOW LOOKS TO TURN
NORTHWESTERLY ON TUESDAY FOR A RETURN OF THE CLIPPER EXPRESS.
BORSUM
&&
.AVIATION...
WINTER WEATHER WILL CONTINUE TO IMPACT THE REGION. BLIZZARD
CONDITIONS WILL IMPACT KLVM WITH VLIFR UNTIL MIDDAY. CONDITIONS
WILL IMPROVE BUT MORE SNOW WILL BRING LOWER CEILINGS AND KEEP
VISIBILITIES NO BETTER THAN MVFR. KMLS WILL HAVE THE SNOW ARRIVE
THIS AFTERNOON COMBINING WITH INCREASED WINDS PRODUCING IFR
CONDITIONS. KBIL AND KSHR WILL SEE LIGHTER SNOWFALL AND LESS WIND
SO CONDITIONS WILL DECREASE TO MVFR THIS AFTERNOON AND APPROACH
IFR AT TIMES. BORSUM
&&
.PRELIMINARY POINT TEMP/POPS...
TDY WED THU FRI SAT SUN MON
-------------------------------------------------------
BIL 024 005/029 022/035 018/034 015/032 021/035 022/033
6/S 61/N 11/N 12/J 21/B 11/B 11/B
LVM 019 007/026 022/034 021/034 019/034 021/032 021/028
4/S 41/Q 11/N 22/J 11/N 11/N 21/N
HDN 024 901/027 016/037 015/032 012/030 018/034 020/033
8/S 61/B 11/B 12/J 21/B 12/J 11/B
MLS 019 907/023 012/032 013/026 010/022 015/030 020/031
9/S 20/B 01/B 12/J 21/B 22/J 11/B
4BQ 022 903/022 013/036 017/031 012/027 018/031 020/032
9/S 31/B 00/B 02/J 21/B 22/J 01/B
BHK 016 911/017 011/029 012/022 010/018 013/028 019/029
9/S 20/B 01/B 12/J 21/E 12/J 11/B
SHR 024 901/027 016/038 016/034 014/033 018/036 020/033
5/S 51/B 00/B 12/J 21/B 11/B 21/B
&&
.BYZ WATCHES/WARNINGS/ADVISORIES...
MT...WINTER WEATHER ADVISORY IN EFFECT UNTIL NOON MST TODAY FOR
ZONES 28-34-41-42-63-64.
WINTER WEATHER ADVISORY IN EFFECT FROM 8 AM THIS MORNING TO 9
PM MST THIS EVENING FOR ZONES 31>33-36-37-58.
BLIZZARD WARNING IN EFFECT UNTIL NOON MST TODAY FOR ZONES
65-66.
WY...NONE.
&&
$$
WEATHER.GOV/BILLINGS
AREA FORECAST DISCUSSION
NWS OMAHA/VALLEY NE
247 PM CST TUE DEC 10 2013
.SHORT TERM...TONIGHT THROUGH FRIDAY.
MAIN ISSUE IN THE SHORT TERM DEALS WITH FAST MOVING CLIPPER EARLY
TONIGHT.
EARLY AFTERNOON SATELLITE IMAGERY SHOWED UPPER SHORTWAVE ENERGY
DIGGING THRU MT INTO NRN WY. MOISTURE WITH THIS SYSTEM WILL BE
QUITE LIMITED AS IT PASSES THROUGH NEBR...ALTHOUGH WITH ARCTIC
NATURE TO AIRMASS ASSOCD WITH IT...ANY SNOW TO LIQUID RATIOS WILL
BE HIGH AND COULD AVERAGE AROUND 20-1 OR BETTER. ALTHOUGH THERE
WAS FAIRLY DECENT MODEL AGREEMENT IN PLACING THE HIGHER QPF FROM
THIS SYSTEM MOSTLY N-NE OF FORECAST AREA...WITH H5/H7 HEIGHT
FALLS WITH IT AT 12Z OVER WRN MT-ERN WA...SOME DIGGING IS
POSSIBLE. THUS WILL LEAN TOWARD 17Z RAP IN PLACING A SECOND AREA
OF LIGHT PRECIP FARTHER SW REACHING NWRN ZONES BY EARLY EVENING
AND NEAR THE OMAHA METRO AN HR OR TWO EITHER SIDE OF MIDNIGHT.
WITH TEMPERATURES FALLING SHARPLY BEHIND CLIPPER/ARCTIC FRONT LATE
TNGT/WED AM...WILL ADJUST HOURLIES TO ACCOUNT FOR A 14Z LOW NEAR A
MAV/MET BLEND FOR NOW. A FEW NRN COUNTIES TOUCH -20 WIND CHILLS
FOR AN HOUR OR TWO WED MORNING BUT WITH AREAL COVERAGE AND LENGTH
OF TIME OF COLDEST LIMITED...NO HEADLINES AT THIS TIME.
NEXT FAST MOVING CLIPPER WAS FORECAST TO ALREADY BRING RETURN
FLOW TO AREA BY WED EVENING...ALTHOUGH THIS ONE FORECAST TO BE
FARTHER NE AND WEAKER...SO NO PRECIP EXPECTED FOR US. COUNTING ON
ENOUGH DECOUPLING IN THE EVENING TO ALLOW READINGS TO FALL INTO
LOW/MID SINGLE DIGITS...WHICH POSSIBLY MAY NOT BE MUCH LOWER THAN
SOME AFTN TEMPS NERN ZONES. NON-DIURNAL ADJUSTMENTS WILL BE MADE
AS WELL WITH READINGS LEVELING OFF/RISING LATER WED NIGHT.
THURSDAY APPEARS AT LEAST AS MILD AS TODAY IF NOT WARMER AS H85
TEMPS ARE AT LEAST +5 DEG C WARMER THAN TDA. SNOW COVER WILL
MODERATE WARMUP AND THUS MAX TEMPS WERE KEPT ON LOWER SIDE OF
GUIDANCE...EXCEPTION MAY BE THINNER AREA OF SNOW COVER PARTS OF
WCNTRL ZONES NEAR/NW OF COLUMBUS.
WINDS SHOULD DROP OFF THU EVENING AS A WEAK FRONT SLIPS INTO NEBR
...THUS TEMPS WERE LOWERED WITH LIGHTER WINDS EXPECTED AND
RESIDUAL SNOW LINGERING. LEFT FRIDAY DRY FOR NOW AS MOISTURE
ARRIVING PER CROSS SECTIONS WAS SHALLOW UNTIL NEAR OR AFTER 00Z
SAT. THAT SAID A FASTER SOLUTION OR A BIT DEEPER LOW LEVEL
MOISTURE COULD ALLOW FOR A LIGHT PRECIP MIX TO DEVELOP SERN ZONES
LATE IN THE AFTERNOON AND THIS WILL NEED MONITORING IN LATER
FORECASTS. KEPT HIGHS MOSTLY AOB FREEZING.
.LONG TERM...FRIDAY NIGHT THROUGH TUESDAY
MODEL CONTINUITY IS NOT GREAT IN THE EXTENDED...WITH LOW CONFIDENCE
ON TEMPERATURE SWINGS AND CHANCES FOR PRECIPITATION ASSOCIATED WITH
FAST-MOVING AND POORLY-TIMED SHORTWAVES. AS A RESULT...KEPT
FORECAST GRIDS CLOSE TO THE BLENDS FOR NOW...UNTIL BETTER AGREEMENT
OR RUN-TO-RUN CONSISTENCY FAVORS ONE SOLUTION OVER ANOTHER.
ECMWF/GFS INDICATE SOME POTENTIAL FOR FLURRIES OR LIGHT SNOW ON
FRIDAY NIGHT AS AN UPPER-LEVEL TROUGH KICKS OUT OF THE SOUTHERN
PLAINS AND ACROSS KS/MO...WITH A NORTHERN STREAM TROUGH ALSO
DIVING OUT OF THE DAKOTAS TOWARD IA. BETTER CHANCES OF PRECIP
EXIST TO OUR EAST AS THE TWO WAVES APPROACH EACH OTHER...LIKELY
PHASING OVER THE GREAT LAKES...BUT POTENTIAL FOR LIGHT SNOW
WARRANTS SLIGHT CHANCE POPS IN OUR EAST FOR NOW. IN WAKE OF THE
TROUGH...COLD AIR WILL SPILL INTO THE AREA AGAIN FOR AT LEAST
SUNDAY...BRINGING TEMPS WELL BELOW CLIMO AT LEAST FOR THE DAY
BEFORE SOME MODERATION ARRIVES ON SUNDAY NIGHT/MONDAY. ECMWF
SOLUTION ON MONDAY/TUESDAY HAS 850MB TEMPS SEVERAL DEGREES COOLER
THAN GFS...AND ALSO IS A LITTLE MORE ACTIVE...WITH SHORTWAVES
BRINGING AT LEAST CLOUDS IF NOT VERY LIGHT PRECIPITATION ON BOTH
SUNDAY AND MONDAY...WHILE GFS REMAINS DRY. HAVE KEPT GRIDS DRY
FROM SUNDAY ONWARD...AS ANY PRECIP CHANCES THAT DO APPEAR IN MODEL
SOLUTIONS SEEM VERY LIGHT...WEAKLY FORCED...AND FAST MOVING. BOTH
CLOUDS AND SNOW COVER COULD HOLD TEMPS BACK EVEN IF MID-LEVEL
TEMPERATURES DO WARM INTO THE SINGLE DIGITS ABOVE ZERO...AND
THOUGHT BLENDS CAPTURED TEMPERATURE POTENTIAL WELL ENOUGH FOR NOW.
MAYES
&&
.AVIATION...
18Z TAFS FOR KOMA...KLNK...KOFK.
FAST MOVING CLIPPER SYSTEM COMING OUT OF THE NORTHERN HIGH
PLAINS WILL DRAG ANOTHER COLD FRONT THROUGH EASTERN NEBRASKA
BETWEEN 00Z-06Z WITH WINDS SHIFTING TO THE NORTHWEST AND
INCREASING TO 10-20KTS. MAIN BAND OF SNOW EXPECTED NORTH AND EAST
OF TAF SITES WITH MID LEVEL CIGS THROUGH 09Z THEN CLEARING.
FOBERT
&&
.OAX WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
IA...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS BINGHAMTON NY
1035 PM EST WED DEC 11 2013
.SYNOPSIS...
LAKE EFFECT SNOW WILL CONTINUE EAST AND SOUTHEAST OF LAKES ONTARIO
AND ERIE...OCCASIONALLY BRINGING SNOW SQUALLS TO THE REGION THROUGH
FRIDAY. A VERY COLD AIR MASS WILL KEEP TEMPERATURES BELOW NORMAL
THE REST OF THIS WEEK. A STORM SYSTEM THIS WEEKEND MAY BRING
ACCUMULATING SNOWFALL TO ALL OF NORTHEAST PENNSYLVANIA AND CENTRAL
NEW YORK.
&&
.NEAR TERM /THROUGH THURSDAY/...
RADAR SHOWS THE LAKE ONTARIO BAND BEGINNING TO MAKES ITS MOVE TO
THE SOUTH AND EAST AT THIS TIME. STILL HAVE SNOW FALLING IN NW
ONEIDA COUNTY SO OPTED TO KEEP WARNING GOING. NEXT UPDATE PROBABLY
WILL BE ABLE TO DROP IT AS SNOWS SHUD BE TO THE SOUTH IN THE NEXT
FEW HOURS. SHORT RANGE MESOSCALE MODELS INDICATE THAT A FAIRLY
STRG SFC HIGH TRIES TO BUILD IN BEHIND THE DEPARTING SHRT WAVE
THAT WAS MOVING INTO NRN NEW ENGLAND AND SERN CANADA AT THIS
TIME. THE EFFECT OF THIS WAS TO VEER THE LL WINDS TO N OR NERLY UP
TO 925 MB IN NC NY WHICH IN EFFECT SHIFTS THE LES BANDS WELL TO
THE W AND WEAKENS THE ACVTY AS VERY DRY BNDRY LAYER AIR MOVES IN.
DWPTS WERE IN THE SINGLE DIGITS SUGGESTING VERY DRY AIR WHICH WUD
CUT DOWN LES POTENTIAL FOR OVRNGT. THE HRRR...LOCAL WRF...WRF-ARW AND
WRF- NMM AND EVEN THE RAP ALL SUGGEST THIS. HOWEVER...THE VWP FROM
KTYX DOES NOT SHOW THIS LL NERLY FLOW AS IT REMAINS NWRLY. THIS
SUGGESTS THAT THESE MESOSCALE MODELS WERE OVERDOING THIS SFC HIGH
WHICH WAS BUILDING TO OUR NORTH. THE NEW 00Z NAM KEEPS A LL NW FLO
DOWN INTO THE LES ADVY AREA ALL NGT AND HENCE...GIVEN THIS NEW MODEL
DATA...RADAR TRENDS AND THE KTYX VWP I THINK OUR LES ADVY FOR NC
NY STILL LOOKS GOOD. TWEAKED AMNTS A TAD BUT GENERALLY 4 TO 7
INCHES WILL FALL IN MUCH OF THIS AREA OVERNIGHT AND THU AM. THE
FLO ACRS THE ENTIRE AREA GOES W-SWRLY THU DURING THE DAY AND THE
LES WILL RAPIDLY SHIFT BACK N THU.
THE LAKE ERIE BAND HAS NOW WORKED OFF OF LAKE ERIE IN THE NW FLO
PATTERN AND WILL ADVECT SOUTHEASTWARD AND FALL APART AS IT MOVES
INTO NE PA AS PER MODEL GUIDC. THERE WILL BE SUBSC AS WELL BEHIND
THE DEPARTING SHRT WAVE AND THE BAND WILL BECOME MOISTURE STARVED
AS IT WORKS AWAY FROM THE LAKE. HENCE NAM AND OTHER MESO MODELS
LOOK ON TRACK WITH THIS BAND FALLING APART IN NE PA AND THE
CATSKILLS NEXT FEW HOURS.
&&
.SHORT TERM /THURSDAY NIGHT THROUGH FRIDAY NIGHT/...
315 PM UPDATE...
REINVIGORATED LAKE EFFECT SNOW BAND WILL REDEVELOP EAST OF LAKE
ONTARIO THURSDAY NIGHT INTO FRIDAY. SPECIFICS OF EXACTLY WHERE
THAT BAND SETS UP REMAIN TO BE SEEN...BUT THERE IS A GOOD CHANCE
THAT IT WILL INVOLVE NORTHERN ONEIDA COUNTY. DENDRITIC GROWTH
BEGINS TO SLOWLY RISE IN HEIGHT YET ALSO THICKEN WHILE STILL
HAVING OMEGA EXTEND THROUGH IT EVEN INTO FRIDAY MORNING. THIS
ALONG WITH EXPECTED VERY HIGH SNOW TO LIQUID RATIOS COMPELLED ME
TO HOIST ANOTHER LAKE EFFECT SNOW WATCH FOR NORTHERN ONEIDA
COUNTY. EXTREME NORTHERN ONEIDA COUNTY POTENTIAL FOR MORE THAN 6
INCHES OF SNOW LOOKS PRETTY GOOD...AND INDEED IF THE BAND ENDS UP
SITTING THERE INSTEAD OF JUST NORTH...ACCUMULATIONS COULD BE MUCH
MORE. AS WITH ALL LAKE EFFECT...THE HIGHEST AMOUNTS WILL BE
LOCALIZED WITH ONE SPOT GETTING MANY INCHES AND OTHERS JUST A FEW
MILES AWAY SIGNIFICANTLY LESS. MEANWHILE...LAKE ERIE BAND WILL
AGAIN EXTEND SNOW SHOWERS ACROSS MUCH OF CENTRAL NEW YORK WITH
LIGHT FLUFFY ACCUMULATIONS POSSIBLE.
WAVE ASSOCIATED WITH WARM AIR ADVECTION ALOFT...AND SHEARING LOW
LEVEL FLOW...SHOULD DIMINISH LES INTENSITY DURING THE DAY FRIDAY.
HOWEVER...THE WAVE ITSELF COULD YIELD SOME LIGHT SYNOPTIC SNOW
OUTSIDE OF LES AREAS.
&&
.LONG TERM /SATURDAY THROUGH WEDNESDAY/...
MAIN ISSUE DURING THE LONG TERM PERIOD CONTINUES TO BE POTENTIAL
FOR WIDESPREAD SNOWS AND EVEN THE POSSIBILITY FOR SOME MIXED
PRECIP ACROSS THE LWR WYOMING VLY AND POCONOS BEGINNING SATURDAY
AND LASTING INTO SATURDAY NIGHT/EARLY SUNDAY. DURING THIS
TIMEFRAME...FCST MODELS CONTINUE TO ADVERTISE A NORTHERN STREAM
WAVE DIVING SOUTH AND EAST ACROSS THE WESTERN GREAT LAKES/UPPER
MIDWEST...WHILE ANOTHER SOUTHERN STREAM WAVE EJECTS FROM THE
SOUTHERN PLAINS INTO THE LOWER MISS RVR VLY. AS BOTH UPPER WAVES
DIG...MODELS AGREE THAT A FRONTAL BOUNDARY STALLED TO OUR SOUTH
WILL BEGIN ADVANCING NORTH ONCE AGAIN AS A CONSOLIDATING 850-MB
LOW BEGINS MOVING NORTHEAST FROM THE MID MISS VLY INTO SOUTHERN
ONTARIO PROVINCE BY 00Z SUNDAY. AHEAD OF THIS FEATURE...EXPECT
DEVELOPING WARM AIR ADVECTION SNOWS AS 850-MB FLOW INCREASES TO
NEAR 30 KTS AND ISENTROPIC ASCENT INCREASES ALONG THE 285 AND 290K
THETA SURFACES. FROM THIS VANTAGE POINT...WARM AIR ADVECTION SNOWS
LOOK TO CONTINUE THROUGH A GOOD PART OF THE DAY AS FIRST THE
850-MB LOW CENTER TRACKS NORTH AND EAST OF OUR FCST AREA...AND THE
SOUTHERN STREAM SFC REFLECTION MOVES OFF THE SOUTHEASTERN VIRGINA
COAST BY 00Z SUNDAY. UNDER THIS SCENARIO...MUCH OF THE FCST AREA
WILL REMAIN IN THE NORTHWEST QUADRANT OF THE PRIMARY SFC FEATURE
THUS ENSURING LOW-LEVEL COLD AIR WILL REMAIN IN PLACE THROUGH MUCH
OF THE EVENT. THE ONLY EXCEPTION AS OF RIGHT NOW APPEARS TO BE ACROSS
THE LWR WYOMING VLY AND POCONOS SATURDAY NGT WHERE SOME WARM AIR
MAY TEMPORARILY ADVANCE INTO NORTHEAST PA AS ENERGY FROM THE
NORTHERN STREAM SFC LOW TRANSFERS TO THE MAIN LOW OFF THE
ATLANTIC SEABOARD. SNOWS EXPECTED TO CONTINUE THROUGH MUCH OF THE
OVERNIGHT AS MOISTURE WRAPS IN FROM THE MAIN LOW OFF THE COAST
AND ADDITIONAL FORCING FOR ASCENT BECOMING MORE APPARENT AS PVA
INCREASES IN ADVANCE OF AFOREMENTIONED NORTHERN STREAM WAVE
APPROACHING FROM THE CENTRAL LAKES AND SOUTHERN ONTARIO. AS A
RESULT...CONFIDENCE IS INCREASING THAT SEVERAL INCHES OF SYNOPTIC
SNOW CAN BE EXPECTED ACROSS THE AREA THROUGH THE WEEKEND. FOR
NOW...WILL HIGHLIGHT CONCERNS ON THE HWO PRODUCT UNTIL FCST
DETAILS BECOME MORE CERTAIN PENDING ADDITIONAL MODEL GUIDANCE.
BEYOND THIS...BROAD NORTHWEST FLOW TO RESULT IN REDEVELOPING LAKE
SNOWS EAST AND SOUTHEAST OF BOTH LAKES EARLY INTO NEXT WEEK...WITH
ADDITIONAL SYNOPTIC SNOWS POSSIBLE MONDAY NIGHT/EARLY TUESDAY AS
ELONGATED WARM FRONT ADVANCES NORTH ACROSS THE AREA. TEMPS THROUGH
THE PERIOD LOOK TO HOVER SLIGHTLY BELOW NORMAL AS COOL NORTHWEST
FLOW REMAINS IN PLACE.
&&
.AVIATION /04Z THURSDAY THROUGH MONDAY/...
MAIN CONCERN DURING THIS FCST PERIOD CONTINUES TO BE LAKE EFFECT
SNOWS ACROSS ALL CENTRAL NEW YORK TERMINALS. ARCTIC COLD FRONT/SFC
TROUGH CURRENTLY WORKING THROUGH THE AREA WITH LATEST RADAR DATA
FROM TYX SHOWING A GRADUAL SOUTHWARD SHIFT OF MAIN LAKE ONTARIO
BAND. ADDITIONAL ACTIVITY OFF OF LAKE ERIE NOW IMPACTING THE
CENTRAL FINGER LAKES TO INCLUDE ITH. THIS BAND TOO SHOULD SHIFT
SOUTH WITH TIME THIS EVENING. INDIVIDUAL FCST POINT SPECIFICS
BELOW:
RME: EXPECT DEVELOPING IFR VSBYS IN SNOW BY 1Z AS BAND SHIFTS
SOUTH THROUGH THE TERMINAL. RESTRICTIONS BELOW ALTERNATE MINS
SHOULD LAST THROUGH 5Z BEFORE BAND SHIFTS SOUTH OF TERMINAL. VFR
EXPECTED BY 07Z.
SYR: LAKE SNOWS TO GRADUALLY SHIFT SOUTH OVER THE TERMINAL TOWARDS
2Z WITH A CONTINUATION OF IFR RESTRICTIONS (BELOW ALTERNATE MINS)
EXPECTED THROUGH 8-10Z. FOLLOWING THIS...WIND FIELDS WEAKEN
CONSIDERABLY WHICH SHOULD RETRACT MAIN SNOW ACTIVITY CLOSER TO THE
IMMEDIATE LAKE SHORE. AS THIS OCCURS...EXPECT IMPROVEMENTS TO
HIGH-END MVFR AND POSSIBLE VFR TOWARDS EARLY MORNING.
ITH: LAKE ERIE BAND DIRECTLY OVER THE TERMINAL TO START OUT WITH
IFR EXPECTED TO CONTINUE THROUGH THE 3Z TIME FRAME. FOLLOWING
THIS...LAKE ERIE BAND SHOULD SHIFT SOUTH WITH MVFR CONDITIONS
(MAINLY CIGS) EXPECTED IN ITS WAKE. LAKE ERIE BAND TO RE-INTENSIFY
AFTER 20Z WHICH MAY LEAD TO OCCASIONAL MVFR VSBYS DURING THE LATE
AFTERNOON HRS.
ELM: LAKE ERIE BAND TO SHIFT SOUTH OVER THE TERMINAL BY 2 OR 3Z...WITH
MVFR VSBYS (OCCASIONAL IFR) POSSIBLE FOR A SHORT PERIOD OF TIME.
VFR EXPECTED BY 5Z AS BAND DISSIPATES.
BGM: LAKE ERIE BAND TO ALSO SHIFT SOUTH OVER THE TERMINAL BY
2Z...WITH OCCASIONAL IFR (BELOW ALTERNATE MINS) EXPECTED THROUGH
5Z OR SO. BEYOND THIS...EXPECT MVFR CIGS WITH LGT SN AS FLOW
BECOMES NORTHWEST WITH TIME.
AVP: MAINLY VFR EXPECTED THROUGH THE FCST PERIOD AS MAIN LAKE
EFFECT ACTIVITY REMAINS NORTH. SOME LAKE SNOWS MAY BRIEFLY MOVE
OVER THE TERMINAL TOWARDS 6Z...HOWEVER CONFIDENCE IS NOT HIGH
ENOUGH AT THIS POINT TO INCLUDE ANY RESTRICTIONS IN CURRENT FCST.
OUTLOOK...
FRI...MAINLY VFR...HOWEVER RESTRICTIONS POSSIBLE IN LAKE EFFECT
SNOW AT KRME.
SAT/SUN...RESTRICTIONS LIKELY REGION-WIDE IN SNOW AS STORM SYSTEM
MOVES THROUGH THE AREA.
SUN NGT/MON...RESTRICTIONS POSSIBLE FROM LAKE EFFECT SNOW SHOWERS
ESPECIALLY KSYR-KRME.
&&
.BGM WATCHES/WARNINGS/ADVISORIES...
PA...NONE.
NY...LAKE EFFECT SNOW WATCH FROM THURSDAY AFTERNOON THROUGH FRIDAY
AFTERNOON FOR NYZ009.
LAKE EFFECT SNOW WARNING UNTIL 6 AM EST THURSDAY FOR NYZ009.
LAKE EFFECT SNOW ADVISORY UNTIL 11 AM EST THURSDAY FOR NYZ017-
018-036-037-044-045.
&&
$$
SYNOPSIS...DJN
NEAR TERM...DJN
SHORT TERM...MDP
LONG TERM...CMG
AVIATION...CMG
AREA FORECAST DISCUSSION
NWS WILMINGTON NC
1155 AM EST TUE DEC 10 2013
.SYNOPSIS...
A COLD FRONT WILL SLOWLY MOVE ACROSS THE AREA TODAY BRINGING
WIDESPREAD LIGHT RAINFALL. DRY AND COOL CONDITIONS WILL DEVELOP
WEDNESDAY AND CONTINUE THROUGH FRIDAY. THE WEEKEND IS LOOKING MORE
AND MORE UNSETTLED AS A STORM SYSTEM DEVELOPS IN THE SOUTHEAST.
COOLER AND DRIER CONDITIONS ARE EXPECTED EARLY NEXT WEEK.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 1130 AM TUESDAY...COMPLEX WEATHER SCENARIO FOR TODAY WITH LOW
PRESSURE SYSTEM OVER THE CAROLINAS. WARM AND MOIST AIR IN
PLACE AHEAD OF COLD FRONT BUT RADAR SHOWING DISTINCT LINE OF
SHALLOW CONVECTION WITH DISTINCT WIND SHIFT BEHIND IT...BUT NO
TEMP CHANGE. THIS LINE WILL ADVANCE EAST BRINGING A QUICK SHOT OF
PCP UP TO A TENTH OF AN INCH AS NOTED ON OBS. THIS LINE WILL REACH THE
COAST BETWEEN 1 AND 2PM BRINGING GUSTY WESTERLY WINDS BEHIND IT.
FLORENCE AND LUMBERTON OBS SHOWED A GUST AROUND 30 MPH JUST AFTER 11
AM.
PCP WILL KEEP TEMPS FROM RISING TOO MUCH IN MOST PLACES AND THEN
COLD FRONT WILL PUSH THROUGH BY EARLY TO MID AFTN. TEMPS AT H85
WILL RISE UP TO 12C BY NOON TIME AND THEN WILL PLUMMET THROUGH
THIS AFTN DOWN CLOSE TO 4C BY MIDNIGHT.
COOLER WATERS KEEPING TEMPS MUCH COOLER...CLOSER TO 60...ALONG
THE BEACHES AND UP THROUGH BRUNSWICK COUNTY WHERE ON SHORE FLOW IS
MAXIMIZED. THIS IS ALSO LEADING TO ANOTHER ROUND OF SEA FOG AS
WARMER MOISTER AIR JUST ABOVE THE SURFACE IS MOVING ATOP THE COOLER
WATERS. ISSUED SPECIAL WEATHER STATEMENT TO ADDRESS LOCALIZED FOG
OVER SHELF WATERS SOUTH MAINLY ADVECTING FROM SOUTH OF CAPE FEAR ON
SHORE OVER BRUNSWICK COUNTY.
LLJ UP TO 55 KTS PUMPING PLENTY OF WARM AND MOIST AIR AHEAD OF
COLD FRONT. CONVECTIVE INDICES LOOK LIKE WE COULD SEE SOME LOW TOP
CONVECTION AND POSSIBLY A RUMBLE OF THUNDER. BEST LIFT SHOULD COME
JUST AHEAD OF COLD FRONT THROUGH THIS AFTERNOON LEAVING A NARROW
WINDOW BUT MAY INCLUDE MENTION OF ISO THUNDER IN GRIDS. SFC BASED
CAPE VALUES REACH UP TO 600 JKG. MAY SEE MORE STABLE MARINE LAYER
COME INTO PLAY AS STORMS MOVE CLOSER TO THE COAST...BUT EXPECT
SHOWERS AHEAD OF FRONT THROUGH EARLY AFTERNOON.
WINDS WILL COME AROUND TO THE W-NW BY EARLY THIS AFTERNOON BUT
COLD AIR WILL LAG BEHIND. PLENTY OF COLD AND DRY AIR WILL ADVECT
IN AND SCOUR OUT ALL THE LOW CLOUDS...FOG AND ANY SHOWERS OR PCP
ACROSS THE AREA. THIS WILL LEAD TO FALLING TEMPS ACROSS THE AREA
THROUGH THIS EVENING.
AS A STRONG COLD SURGE BARRELS SOUTHEAST ACROSS THE EASTERN
CAROLINAS A STRONG COLD ADVECTION REGIME SETS UP WITH ABOUT A 40
DEGREE DROP IN BOTH TEMPS AND DEWPOINT TEMPS BY MORNING AS COLD
AND DRY AIR COMES RUSHING IN. CLEARING SKIES OVERNIGHT WILL COMBINE
WITH CONTINUED COLD ADVECTION TO ALLOW MINIMUM TEMPERATURES TO DIP
INTO THE LOWER TO MID 30S.
&&
.SHORT TERM /WEDNESDAY THROUGH THURSDAY NIGHT/...
AS OF 3 AM TUESDAY...THE MID LEVEL PATTERN WILL CONSIST OF AN INITIAL
WESTERLY FLOW TRANSITIONING INTO MORE OF A NORTHWEST FLOW THURSDAY.
THE ONLY FORECAST DILEMMA IS TEMPERATURES AS SURFACE HIGH PRESSURE
AND PRECIPITABLE WATER VALUES LESS THAN ONE QUARTER INCH KEEP EVEN
CLOUDS OUT OF THE MIX FOR THE MOST PART.
A SECONDARY SHORTWAVE EMBEDDED IN THE MEAN FLOW WILL REINFORCE THE
COLD AIR THURSDAY WITH 850MB VALUES ACTUALLY DROPPING TO JUST BELOW
ZERO DEGREES C. THE TIMING OF THE COLD AIR ADVECTION IS CRITICAL AS
THE MET IS A LITTLE QUICKER AND HENCE HIGH TEMPERATURES IN THE
GUIDANCE BULLETINS ARE ABOUT A CATEGORY COOLER. THE FORECAST
CONTINUES TO OPT FOR A BLEND. FRIDAY MORNING WILL BE QUITE COOL WITH
MOST AREAS SEEING MID TO UPPER 20S.
&&
.LONG TERM /FRIDAY THROUGH MONDAY/...
AS OF 3 AM TUESDAY...THE MEDIUM RANGE GUIDANCE APPEARS TO BE COMING INTO
BETTER AGREEMENT WITH THE SCENARIO FOR THE WEEKEND. A SOMEWHAT DEEP
ALBEIT PROGRESSIVE MID LEVEL TROUGH WILL MOVE OUT FROM THE SOUTHWEST
AND ATTEMPT TO PHASE WITH A MODEST SYSTEM TO THE NORTH. THIS ALLOWS
A COMPLEX AREA OF LOW PRESSURE TO DEVELOP IN THE SOUTHEAST AND MOVE
UP THE COAST...EVENTUALLY REDEVELOPING OFF THE DELMARVA AND
DEEPENING. THE GFS CONTINUES TO BE A LITTLE FASTER OF THE GUIDANCE
AND HAVE INCREASED POPS TO MATCH ADJACENT OFFICES BETTER BUT OVERALL
THE LIONS SHARE OF POPS/QPF WILL OCCUR SATURDAY INTO SUNDAY MORNING.
HAVE TRIMMED BACK POPS FOR LATER SUNDAY FOR THE SAME REASONS. NO
CHANGES TO TEMPERATURE FORECAST.
&&
.AVIATION /16Z TUESDAY THROUGH SATURDAY/...
AS OF 12Z...AN AREA OF PRE-FRONTAL SHOWERS IS ALONG THE I-95
CORRIDOR...MOVING SLOWLY EAST. THE HRRR MODEL HAS THIS BATCH OF
SHOWERS MOVING OUR OF THE REGION LATER THIS MORNING...REPLACE WITH
ANOTHER BATCH OF CONVECTION ALONG THE FRONT BY EARLY AFTERNOON.
CONDITIONS AHEAD OF THE FRONT WILL LIKELY BOUNCE AROUND BOTH
VISIBILITIES AND CEILINGS. FRONT WILL MOVE THROUGH THE INLAND
TERMINALS BY EARLY AFTERNOON...THE COAST BY LATE AFTERNOON. POST
FRONTAL...EXPECT A WIND SHIFT TO THE NORTH NORTHWEST...GUSTY WITH
IMPROVING CONDITIONS. AN MVFR CEILING MAY BRIEFLY
OCCUR...PREDOMINATELY VFR THROUGH THE END OF THE FORECAST PERIOD.
EXTENDED OUTLOOK...INCREASING CONFIDENCE FOR VFR WEDNESDAY THROUGH
FRIDAY. SHOWERS POSSIBLE SATURDAY AHEAD OF AN APPROACHING LOW
PRESSURE SYSTEM.
&&
.MARINE...
NEAR TERM /THROUGH TONIGHT/...
AS OF 1130 AM TUESDAY...AREAS OF DENSE FOG CONTINUES ACROSS THE
WATERS BUT GUSTY WESTERLY WINDS WILL WORK THEIR WAY IN BEHIND LINE
OF CONVECTION HEADING OVER THE WATERS EARLY THIS AFTERNOON.
SMALL CRAFT ADVISORY REMAINS IN EFFECT. FRYING PAN SHOWING SEAS
CLOSE TO 9 FT...AS WINDS AND SEAS INCREASE IN ADVANCE OF A STRONG
COLD FRONT. WINDS WILL TURN W-NW AND BECOME GUSTY THIS AFTERNOON
CAUSING NEAR-SHORE SEAS TO SUBSIDE. ALL LOCAL WATERS WILL DROP
BELOW SMALL CRAFT ADVISORY CRITERIA IN STRONG OFF SHORE FLOW BY
TONIGHT.
SHORT TERM /WEDNESDAY THROUGH THURSDAY/...
AS OF 3 AM TUESDAY...OVERALL CONDITIONS NOT TOO BAD CONSIDERING HIGH
PRESSURE WILL BE MOVING IN FROM THE WEST/NORTHWEST. FOR
WEDNESDAY...WINDS WILL BE FROM THE NORTHEAST AROUND TEN KNOTS AND
MAY BE LOWER AS THE PATTERN BRIEFLY RELAXES LATE IN THE DAY. COLD
AIR ADVECTION DEVELOPS AGAIN THURSDAY WHICH WILL KICK WINDS UP TO
15-20 KNOTS FROM THE NORTH. SEAS WILL BE REFLECTIVE OF THE
WINDS...1-3 FEET MOST OF WEDNESDAY INTO EARLY THURSDAY INCREASING
WITH THE WINDS TO 3-5 FEET LATE IN THE PERIOD.
LONG TERM /FRIDAY THROUGH SATURDAY/...
AS OF 3 AM TUESDAY...EXPECT RELATIVELY BENIGN WINDS AND SEAS FOR
FRIDAY AS THE CENTER OF HIGH PRESSURE MOVES OVERHEAD. WINDS
INCREASE AND VEER MORE TO THE SOUTHEAST AS A STORM SYSTEM DEVELOPS
IN THE SOUTHEAST. STILL A LOT OF DETAILS TO IRON OUT WITH THIS
SYSTEM BUT OVERALL MARINERS SHOULD EXPECT THIS TREND OF INCREASING
WINDS AND SEAS FOR SATURDAY.
&&
.ILM WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
NC...NONE.
MARINE...DENSE FOG ADVISORY UNTIL 1 PM EST THIS AFTERNOON FOR AMZ250-
252-254-256.
SMALL CRAFT ADVISORY UNTIL 7 PM EST THIS EVENING FOR AMZ250-
252-254-256.
&&
$$
NEAR TERM...RGZ
SHORT TERM...SHK
LONG TERM...SHK
AVIATION...DL
AREA FORECAST DISCUSSION
NWS WILMINGTON NC
1026 AM EST TUE DEC 10 2013
.SYNOPSIS...
A COLD FRONT WILL SLOWLY MOVE ACROSS THE AREA TODAY BRINGING
WIDESPREAD LIGHT RAINFALL. DRY AND COOL CONDITIONS WILL DEVELOP
WEDNESDAY AND CONTINUE THROUGH FRIDAY. THE WEEKEND IS LOOKING MORE
AND MORE UNSETTLED AS A STORM SYSTEM DEVELOPS IN THE SOUTHEAST.
COOLER AND DRIER CONDITIONS ARE EXPECTED EARLY NEXT WEEK.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 930 AM TUESDAY...COMPLEX WEATHER SCENARIO FOR TODAY WITH LOW
PRESSURE SYSTEM OVER THE CAROLINAS. WARM AIR STREAMING NORTHWARD
AHEAD OF COLD FRONT OVER WESTERN CAROLINAS. TEMPS ALREADY HIT 70
AT WILMINGTON AIRPORT AND WIDESPREAD 60S AS WARMER AIR IS MIXING
DOWN WITH A DEEPER AND INCREASING WARM AND MOIST SOUTHERLY FLOW.
DENSER COLDER AIR HELD ON OVER CENTRAL TO NORTHERN
CAROLINAS...JUST UPSTREAM OF FORECAST AREA. THE WARM AIR ALOFT
RIDING OVER COLD AIR INLAND PRODUCING DECENT ISENTROPIC LIFT WITH
STEEP INVERSION IN PLACE BASICALLY JUST WEST AND NORTH OF AREA
WHERE WEDGE HELD ON. TEMPS WILL PEAK THIS MORNING BUT CLOUDS...PCP
WILL KEEP TEMPS FROM RISING TOO MUCH IN MOST PLACES AND THEN COLD
FRONT WILL PUSH THROUGH BY EARLY TO MID AFTN. TEMPS AT H85 WILL
RISE UP TO 12C BY NOON TIME AND THEN WILL PLUMMET THROUGH THIS
AFTN DOWN CLOSE TO 4C BY MIDNIGHT.
COOLER WATERS KEEPING TEMPS MUCH COOLER...CLOSER TO 60...ALONG
THE BEACHES AND UP THROUGH BRUNSWICK COUNTY WHERE ON SHORE FLOW IS
MAXIMIZED. THIS IS ALSO LEADING TO ANOTHER ROUND OF SEA FOG AS
WARMER MOISTER AIR JUST ABOVE THE SURFACE IS MOVING ATOP THE COOLER
WATERS. ISSUED SPECIAL WEATHER STATEMENT TO ADDRESS LOCALIZED FOG
OVER SHELF WATERS SOUTH MAINLY ADVECTING FROM SOUTH OF CAPE FEAR ON
SHORE OVER BRUNSWICK COUNTY.
BEST ISENTROPIC LIFT WILL REMAIN JUST NORTH AND WEST OF AREA
WHERE COOLER AIR IS LOCATED BUT SHOULD SEE MORE CONVECTIVE TYPE
PCP IN WARM AND MORE UNSTABLE AIR MASS AHEAD OF FRONT. LLJ UP TO
55 KTS PUMPING PLENTY OF WARM AND MOIST AIR AHEAD OF COLD FRONT. CONVECTIVE
INDICES LOOK LIKE WE COULD SEE SOME LOW TOP CONVECTION AND
POSSIBLY A RUMBLE OF THUNDER. BEST LIFT SHOULD COME JUST AHEAD OF
COLD FRONT THROUGH THIS AFTERNOON LEAVING A NARROW WINDOW BUT MAY
INCLUDE MENTION OF ISO THUNDER IN GRIDS. SFC BASED CAPE VALUES
REACH UP TO 600 JKG. MAY SEE MORE STABLE MARINE LAYER COME INTO
PLAY AS STORMS MOVE CLOSER TO THE COAST...BUT EXPECT SHOWERS AHEAD
OF FRONT THROUGH EARLY AFTERNOON.
THE COLD FRONT BACK TOWARD THE MOUNTAINS THIS MORNING WILL GET A
PUSH FROM MID TO UPPER TROUGH BY MID AFTERNOON AND SHOULD PROGRESS
THROUGH THE I-95 CORRIDOR AROUND 1PM AND REACH THE COAST BY 3 PM. PLENTY
OF COLD AND DRY AIR WILL ADVECT IN BEHIND FRONT AND SCOUR OUT ALL
THE LOW CLOUDS...FOG AND ANY SHOWERS OR PCP ACROSS THE AREA. THIS
WILL LEAD TO FALLING TEMPS ACROSS THE AREA THROUGH THIS EVENING.
AS A STRONG COLD SURGE BARRELS SOUTHEAST ACROSS THE EASTERN
CAROLINAS A STRONG COLD ADVECTION REGIME SETS UP WITH ABOUT A 40
DEGREE DROP IN BOTH TEMPS AND DEWPOINT TEMPS BY MORNING AS COLD
AND DRY AIR COMES RUSHING IN. CLEARING SKIES OVERNIGHT WILL COMBINE
WITH CONTINUED COLD ADVECTION TO ALLOW MINIMUM TEMPERATURES TO DIP
INTO THE LOWER TO MID 30S.
&&
.SHORT TERM /WEDNESDAY THROUGH THURSDAY NIGHT/...
AS OF 3 AM TUESDAY...THE MID LEVEL PATTERN WILL CONSIST OF AN INITIAL
WESTERLY FLOW TRANSITIONING INTO MORE OF A NORTHWEST FLOW THURSDAY.
THE ONLY FORECAST DILEMMA IS TEMPERATURES AS SURFACE HIGH PRESSURE
AND PRECIPITABLE WATER VALUES LESS THAN ONE QUARTER INCH KEEP EVEN
CLOUDS OUT OF THE MIX FOR THE MOST PART.
A SECONDARY SHORTWAVE EMBEDDED IN THE MEAN FLOW WILL REINFORCE THE
COLD AIR THURSDAY WITH 850MB VALUES ACTUALLY DROPPING TO JUST BELOW
ZERO DEGREES C. THE TIMING OF THE COLD AIR ADVECTION IS CRITICAL AS
THE MET IS A LITTLE QUICKER AND HENCE HIGH TEMPERATURES IN THE
GUIDANCE BULLETINS ARE ABOUT A CATEGORY COOLER. THE FORECAST
CONTINUES TO OPT FOR A BLEND. FRIDAY MORNING WILL BE QUITE COOL WITH
MOST AREAS SEEING MID TO UPPER 20S.
&&
.LONG TERM /FRIDAY THROUGH MONDAY/...
AS OF 3 AM TUESDAY...THE MEDIUM RANGE GUIDANCE APPEARS TO BE COMING INTO
BETTER AGREEMENT WITH THE SCENARIO FOR THE WEEKEND. A SOMEWHAT DEEP
ALBEIT PROGRESSIVE MID LEVEL TROUGH WILL MOVE OUT FROM THE SOUTHWEST
AND ATTEMPT TO PHASE WITH A MODEST SYSTEM TO THE NORTH. THIS ALLOWS
A COMPLEX AREA OF LOW PRESSURE TO DEVELOP IN THE SOUTHEAST AND MOVE
UP THE COAST...EVENTUALLY REDEVELOPING OFF THE DELMARVA AND
DEEPENING. THE GFS CONTINUES TO BE A LITTLE FASTER OF THE GUIDANCE
AND HAVE INCREASED POPS TO MATCH ADJACENT OFFICES BETTER BUT OVERALL
THE LIONS SHARE OF POPS/QPF WILL OCCUR SATURDAY INTO SUNDAY MORNING.
HAVE TRIMMED BACK POPS FOR LATER SUNDAY FOR THE SAME REASONS. NO
CHANGES TO TEMPERATURE FORECAST.
&&
.AVIATION /16Z TUESDAY THROUGH SATURDAY/...
AS OF 12Z...AN AREA OF PRE-FRONTAL SHOWERS IS ALONG THE I-95
CORRIDOR...MOVING SLOWLY EAST. THE HRRR MODEL HAS THIS BATCH OF
SHOWERS MOVING OUR OF THE REGION LATER THIS MORNING...REPLACE WITH
ANOTHER BATCH OF CONVECTION ALONG THE FRONT BY EARLY AFTERNOON.
CONDITIONS AHEAD OF THE FRONT WILL LIKELY BOUNCE AROUND BOTH
VISIBILITIES AND CEILINGS. FRONT WILL MOVE THROUGH THE INLAND
TERMINALS BY EARLY AFTERNOON...THE COAST BY LATE AFTERNOON. POST
FRONTAL...EXPECT A WIND SHIFT TO THE NORTH NORTHWEST...GUSTY WITH
IMPROVING CONDITIONS. AN MVFR CEILING MAY BRIEFLY
OCCUR...PREDOMINATELY VFR THROUGH THE END OF THE FORECAST PERIOD.
EXTENDED OUTLOOK...INCREASING CONFIDENCE FOR VFR WEDNESDAY THROUGH
FRIDAY. SHOWERS POSSIBLE SATURDAY AHEAD OF AN APPROACHING LOW
PRESSURE SYSTEM.
&&
.MARINE...
NEAR TERM /THROUGH TONIGHT/...
AS OF 1015 AM TUESDAY...DECIDED ON A DENSE FOG ADVISORY AFTER ALL.
VIS SAT PIX INDICATE THE FOG CONTINUING TO INCREASE IN COVERAGE
EVEN AS BEING RAPIDLY ADVECTED NORTH AND EAST. ADVISORY FOR ALL
ZONES TIL 18Z...AFTER WHICH COLD FRONT WILL RAPIDLY BLOW IT OUT TO
SEA.
AS OF 930 AM TUESDAY...SEA FOG DEVELOPED ONCE AGAIN AS WARM AIR
JUST ABOVE THE SURFACE WAS MOVING OVER COOL SHELF WATERS...MORE
WIDESPREAD JUST SOUTH OF BRUNSWICK. ISSUED SPS FOR NOW BUT MAY
HAVE TO ISSUE DENSE FOG ADVISORY. SMALL CRAFT ADVISORY REMAINS IN
EFFECT TODAY AS WINDS AND SEAS INCREASE IN ADVANCE OF A STRONG
COLD FRONT. WINDS WILL TURN NORTHWEST THIS AFTERNOON AS THE FRONT
MOVES ACROSS THE WATERS...WITH LIMITED FETCH CAUSING NEAR- SHORE
SEAS TO SUBSIDE TO BELOW SMALL CRAFT ADVISORY CRITERIA TONIGHT.
CURRENT OBS SHOW CONDITIONS OVER THE COASTAL WATERS ARE STILL ON
THE BENIGN SIDE...WITH SW WINDS OF ONLY AROUND 5 KTS...AND 3 TO 4
FT SEAS.
SHORT TERM /WEDNESDAY THROUGH THURSDAY/...
AS OF 3 AM TUESDAY...OVERALL CONDITIONS NOT TOO BAD CONSIDERING HIGH
PRESSURE WILL BE MOVING IN FROM THE WEST/NORTHWEST. FOR
WEDNESDAY...WINDS WILL BE FROM THE NORTHEAST AROUND TEN KNOTS AND
MAY BE LOWER AS THE PATTERN BRIEFLY RELAXES LATE IN THE DAY. COLD
AIR ADVECTION DEVELOPS AGAIN THURSDAY WHICH WILL KICK WINDS UP TO
15-20 KNOTS FROM THE NORTH. SEAS WILL BE REFLECTIVE OF THE
WINDS...1-3 FEET MOST OF WEDNESDAY INTO EARLY THURSDAY INCREASING
WITH THE WINDS TO 3-5 FEET LATE IN THE PERIOD.
LONG TERM /FRIDAY THROUGH SATURDAY/...
AS OF 3 AM TUESDAY...EXPECT RELATIVELY BENIGN WINDS AND SEAS FOR
FRIDAY AS THE CENTER OF HIGH PRESSURE MOVES OVERHEAD. WINDS
INCREASE AND VEER MORE TO THE SOUTHEAST AS A STORM SYSTEM DEVELOPS
IN THE SOUTHEAST. STILL A LOT OF DETAILS TO IRON OUT WITH THIS
SYSTEM BUT OVERALL MARINERS SHOULD EXPECT THIS TREND OF INCREASING
WINDS AND SEAS FOR SATURDAY.
&&
.ILM WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
NC...NONE.
MARINE...DENSE FOG ADVISORY UNTIL 1 PM EST THIS AFTERNOON FOR AMZ250-
252-254-256.
SMALL CRAFT ADVISORY UNTIL 7 PM EST THIS EVENING FOR AMZ250-
252-254-256.
&&
$$
NEAR TERM...MBB/RGZ
SHORT TERM...SHK
LONG TERM...SHK
AVIATION...DL
MARINE...SHK
AREA FORECAST DISCUSSION
NWS WILMINGTON NC
1004 AM EST TUE DEC 10 2013
.SYNOPSIS...
A COLD FRONT WILL SLOWLY MOVE ACROSS THE AREA TODAY BRINGING
WIDESPREAD LIGHT RAINFALL. DRY AND COOL CONDITIONS WILL DEVELOP
WEDNESDAY AND CONTINUE THROUGH FRIDAY. THE WEEKEND IS LOOKING MORE
AND MORE UNSETTLED AS A STORM SYSTEM DEVELOPS IN THE SOUTHEAST.
COOLER AND DRIER CONDITIONS ARE EXPECTED EARLY NEXT WEEK.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 930 AM TUESDAY...COMPLEX WEATHER SCENARIO FOR TODAY WITH LOW
PRESSURE SYSTEM OVER THE CAROLINAS. WARM AIR STREAMING NORTHWARD
AHEAD OF COLD FRONT OVER WESTERN CAROLINAS. TEMPS ALREADY HIT 70
AT WILMINGTON AIRPORT AND WIDESPREAD 60S AS WARMER AIR IS MIXING
DOWN WITH A DEEPER AND INCREASING WARM AND MOIST SOUTHERLY FLOW.
DENSER COLDER AIR HELD ON OVER CENTRAL TO NORTHERN
CAROLINAS...JUST UPSTREAM OF FORECAST AREA. THE WARM AIR ALOFT
RIDING OVER COLD AIR INLAND PRODUCING DECENT ISENTROPIC LIFT WITH
STEEP INVERSION IN PLACE BASICALLY JUST WEST AND NORTH OF AREA
WHERE WEDGE HELD ON. TEMPS WILL PEAK THIS MORNING BUT CLOUDS...PCP
WILL KEEP TEMPS FROM RISING TOO MUCH IN MOST PLACES AND THEN COLD
FRONT WILL PUSH THROUGH BY EARLY TO MID AFTN. TEMPS AT H85 WILL
RISE UP TO 12C BY NOON TIME AND THEN WILL PLUMMET THROUGH THIS
AFTN DOWN CLOSE TO 4C BY MIDNIGHT.
COOLER WATERS KEEPING TEMPS MUCH COOLER...CLOSER TO 60...ALONG
THE BEACHES AND UP THROUGH BRUNSWICK COUNTY WHERE ON SHORE FLOW IS
MAXIMIZED. THIS IS ALSO LEADING TO ANOTHER ROUND OF SEA FOG AS
WARMER MOISTER AIR JUST ABOVE THE SURFACE IS MOVING ATOP THE COOLER
WATERS. ISSUED SPECIAL WEATHER STATEMENT TO ADDRESS LOCALIZED FOG
OVER SHELF WATERS SOUTH MAINLY ADVECTIN FROM SOUTH OF CAPE FEAR ON
SHORE OVER BRUNSWICK COUNTY.
BEST ISENTROPIC LIFT WILL REMAIN JUST NORTH AND WEST OF AREA
WHERE COOLER AIR IS LOCATED BUT SHOULD SEE MORE CONVECTIVE TYPE
PCP IN WARM AND MORE UNSTABLE AIR MASS AHEAD OF FRONT. LLJ UP TO
55 KTS PUMPING PLENTY OF WARM AND MOIST AIR AHEAD OF COLD FRONT. CONVECTIVE
INDICES LOOK LIKE WE COULD SEE SOME LOW TOP CONVECTION AND
POSSIBLY A RUMBLE OF THUNDER. BEST LIFT SHOULD COME JUST AHEAD OF
COLD FRONT THROUGH THIS AFTERNOON LEAVING A NARROW WINDOW BUT MAY
INCLUDE MENTION OF ISO THUNDER IN GRIDS. SFC BASED CAPE VALUES
REACH UP TO 600 JKG. MAY SEE MORE STABLE MARINE LAYER COME INTO
PLAY AS STORMS MOVE CLOSER TO THE COAST...BUT EXPECT SHOWERS AHEAD
OF FRONT THROUGH EARLY AFTERNOON.
THE COLD FRONT BACK TOWARD THE MOUNTAINS THIS MORNING WILL GET A
PUSH FROM MID TO UPPER TROUGH BY MID AFTERNOON AND SHOULD PROGRESS
THROUGH THE I-95 CORRIDOR AROUND 1PM AND REACH THE COAST BY 3 PM. PLENTY
OF COLD AND DRY AIR WILL ADVECT IN BEHIND FRONT AND SCOUR OUT ALL
THE LOW CLOUDS...FOG AND ANY SHOWERS OR PCP ACROSS THE AREA. THIS
WILL LEAD TO FALLING TEMPS ACROSS THE AREA THROUGH THIS EVENING.
AS A STRONG COLD SURGE BARRELS SOUTHEAST ACROSS THE EASTERN
CAROLINAS A STRONG COLD ADVECTION REGIME SETS UP WITH ABOUT A 40
DEGREE DROP IN BOTH TEMPS AND DEWPOINT TEMPS BY MORNING AS COLD
AND DRY AIR COMES RUSHING IN. CLEARING SKIES OVERNIGHT WILL COMBINE
WITH CONTINUED COLD ADVECTION TO ALLOW MINIMUM TEMPERATURES TO DIP
INTO THE LOWER TO MID 30S.
&&
.SHORT TERM /WEDNESDAY THROUGH THURSDAY NIGHT/...
AS OF 3 AM TUESDAY...THE MID LEVEL PATTERN WILL CONSIST OF AN INITIAL
WESTERLY FLOW TRANSITIONING INTO MORE OF A NORTHWEST FLOW THURSDAY.
THE ONLY FORECAST DILEMMA IS TEMPERATURES AS SURFACE HIGH PRESSURE
AND PRECIPITABLE WATER VALUES LESS THAN ONE QUARTER INCH KEEP EVEN
CLOUDS OUT OF THE MIX FOR THE MOST PART.
A SECONDARY SHORTWAVE EMBEDDED IN THE MEAN FLOW WILL REINFORCE THE
COLD AIR THURSDAY WITH 850MB VALUES ACTUALLY DROPPING TO JUST BELOW
ZERO DEGREES C. THE TIMING OF THE COLD AIR ADVECTION IS CRITICAL AS
THE MET IS A LITTLE QUICKER AND HENCE HIGH TEMPERATURES IN THE
GUIDANCE BULLETINS ARE ABOUT A CATEGORY COOLER. THE FORECAST
CONTINUES TO OPT FOR A BLEND. FRIDAY MORNING WILL BE QUITE COOL WITH
MOST AREAS SEEING MID TO UPPER 20S.
&&
.LONG TERM /FRIDAY THROUGH MONDAY/...
AS OF 3 AM TUESDAY...THE MEDIUM RANGE GUIDANCE APPEARS TO BE COMING INTO
BETTER AGREEMENT WITH THE SCENARIO FOR THE WEEKEND. A SOMEWHAT DEEP
ALBEIT PROGRESSIVE MID LEVEL TROUGH WILL MOVE OUT FROM THE SOUTHWEST
AND ATTEMPT TO PHASE WITH A MODEST SYSTEM TO THE NORTH. THIS ALLOWS
A COMPLEX AREA OF LOW PRESSURE TO DEVELOP IN THE SOUTHEAST AND MOVE
UP THE COAST...EVENTUALLY REDEVELOPING OFF THE DELMARVA AND
DEEPENING. THE GFS CONTINUES TO BE A LITTLE FASTER OF THE GUIDANCE
AND HAVE INCREASED POPS TO MATCH ADJACENT OFFICES BETTER BUT OVERALL
THE LIONS SHARE OF POPS/QPF WILL OCCUR SATURDAY INTO SUNDAY MORNING.
HAVE TRIMMED BACK POPS FOR LATER SUNDAY FOR THE SAME REASONS. NO
CHANGES TO TEMPERATURE FORECAST.
&&
.AVIATION /12Z TUESDAY THROUGH SATURDAY/...
AS OF 12Z...AN AREA OF PRE-FRONTAL SHOWERS IS ALONG THE I-95
CORRIDOR...MOVING SLOWLY EAST. THE HRRR MODEL HAS THIS BATCH OF
SHOWERS MOVING OUR OF THE REGION LATER THIS MORNING...REPLACE WITH
ANOTHER BATCH OF CONVECTION ALONG THE FRONT BY EARLY AFTERNOON.
CONDITIONS AHEAD OF THE FRONT WILL LIKELY BOUNCE AROUND BOTH
VISIBILITIES AND CEILINGS. FRONT WILL MOVE THROUGH THE INLAND
TERMINALS BY EARLY AFTERNOON...THE COAST BY LATE AFTERNOON. POST
FRONTAL...EXPECT A WIND SHIFT TO THE NORTH NORTHWEST...GUSTY WITH
IMPROVING CONDITIONS. AN MVFR CEILING MAY BRIEFLY
OCCUR...PREDOMINATELY VFR THROUGH THE END OF THE FORECAST PERIOD.
EXTENDED OUTLOOK...INCREASING CONFIDENCE FOR VFR WEDNESDAY THROUGH
FRIDAY. SHOWERS POSSIBLE SATURDAY AHEAD OF AN APPROACHING LOW
PRESSURE SYSTEM.
&&
.MARINE...
NEAR TERM /THROUGH TONIGHT/...
AS OF 930 AM TUESDAY...SEA FOG DEVELOPED ONCE AGAIN AS WARM AIR
JUST ABOVE THE SURFACE WAS MOVING OVER COOL SHELF WATERS....MORE
WIDESPREAD JUST SOUTH OF BRUNSWICK. ISSUED SPS FOR NOW BUT MAY
HAVE TO ISSUE DENSE FOG ADVISORY. SMALL CRAFT ADVISORY REMAINS IN
EFFECT TODAY AS WINDS AND SEAS INCREASE IN ADVANCE OF A STRONG
COLD FRONT. WINDS WILL TURN NORTHWEST THIS AFTERNOON AS THE FRONT
MOVES ACROSS THE WATERS...WITH LIMITED FETCH CAUSING NEAR- SHORE
SEAS TO SUBSIDE TO BELOW SMALL CRAFT ADVISORY CRITERIA TONIGHT.
CURRENT OBS SHOW CONDITIONS OVER THE COASTAL WATERS ARE STILL ON
THE BENIGN SIDE...WITH SW WINDS OF ONLY AROUND 5 KTS...AND 3 TO 4
FT SEAS.
SHORT TERM /WEDNESDAY THROUGH THURSDAY/...
AS OF 3 AM TUESDAY...OVERALL CONDITIONS NOT TOO BAD CONSIDERING HIGH
PRESSURE WILL BE MOVING IN FROM THE WEST/NORTHWEST. FOR
WEDNESDAY...WINDS WILL BE FROM THE NORTHEAST AROUND TEN KNOTS AND
MAY BE LOWER AS THE PATTERN BRIEFLY RELAXES LATE IN THE DAY. COLD
AIR ADVECTION DEVELOPS AGAIN THURSDAY WHICH WILL KICK WINDS UP TO
15-20 KNOTS FROM THE NORTH. SEAS WILL BE REFLECTIVE OF THE
WINDS...1-3 FEET MOST OF WEDNESDAY INTO EARLY THURSDAY INCREASING
WITH THE WINDS TO 3-5 FEET LATE IN THE PERIOD.
LONG TERM /FRIDAY THROUGH SATURDAY/...
AS OF 3 AM TUESDAY...EXPECT RELATIVELY BENIGN WINDS AND SEAS FOR
FRIDAY AS THE CENTER OF HIGH PRESSURE MOVES OVERHEAD. WINDS
INCREASE AND VEER MORE TO THE SOUTHEAST AS A STORM SYSTEM DEVELOPS
IN THE SOUTHEAST. STILL A LOT OF DETAILS TO IRON OUT WITH THIS
SYSTEM BUT OVERALL MARINERS SHOULD EXPECT THIS TREND OF INCREASING
WINDS AND SEAS FOR SATURDAY.
&&
.ILM WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
NC...NONE.
MARINE...SMALL CRAFT ADVISORY UNTIL 7 PM EST THIS EVENING FOR AMZ250-
252-254-256.
&&
$$
SYNOPSIS...
NEAR TERM...RGZ
SHORT TERM...SHK
LONG TERM...SHK
AVIATION...DL
MARINE...SHK
AREA FORECAST DISCUSSION
NWS WILMINGTON NC
647 AM EST TUE DEC 10 2013
.SYNOPSIS...
A COLD FRONT WILL SLOWLY MOVE ACROSS THE AREA TODAY BRINGING
WIDESPREAD LIGHT RAINFALL. DRY AND COOL CONDITIONS WILL DEVELOP
WEDNESDAY AND CONTINUE THROUGH FRIDAY. THE WEEKEND IS LOOKING MORE
AND MORE UNSETTLED AS A STORM SYSTEM DEVELOPS IN THE SOUTHEAST.
COOLER AND DRIER CONDITIONS ARE EXPECTED EARLY NEXT WEEK.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 6:45 AM TUESDAY...CANCELED DENSE FOG ADVISORY EARLY.
OTHERWISE FORECAST CONTINUES WITHOUT CHANGES. PREVIOUS DISCUSSION
FOLLOWS:
QUASI-STATIONARY FRONT WAVERING ACROSS THE FORECAST AREA WILL PUSH
OFFSHORE AS A COLD FRONT THIS AFTERNOON AS A STRONG COLD SURGE
BARRELS SOUTHEAST ACROSS THE EASTERN CAROLINAS. TEMPERATURES WILL
PEAK LATE THIS MORNING IN THE LOWER TO MID 60S BEFORE A STRONG
COLD ADVECTIVE REGIME SETS UP AND DROPS READINGS BACK INTO THE
50S. LIGHT WINDS AND CLEARING SKIES OVERNIGHT WILL COMBINE WITH
CONTINUED COLD ADVECTION TO ALLOW MINIMUM TEMPERATURES TO DIP INTO
THE LOWER TO MID 30S.
PATCHY LIGHT RAIN AND DRIZZLE ARE CURRENTLY MOVING NORTHEAST ACROSS
OUR INLAND COUNTIES ALONG THE FRONTAL BOUNDARY. THE RAIN SHIELD WILL
SPREAD SOUTHEAST ACROSS THE FORECAST AREA THIS MORNING AS THE COLD
FRONT CONSOLIDATES AND DROPS SOUTHEAST. SHOWER ACTIVITY SHOULD END
BY AROUND MID AFTERNOON AS THE FRONT MOVES WELL OFFSHORE.
&&
.SHORT TERM /WEDNESDAY THROUGH THURSDAY NIGHT/...
AS OF 3 AM TUESDAY...THE MID LEVEL PATTERN WILL CONSIST OF AN INITIAL
WESTERLY FLOW TRANSITIONING INTO MORE OF A NORTHWEST FLOW THURSDAY.
THE ONLY FORECAST DILEMMA IS TEMPERATURES AS SURFACE HIGH PRESSURE
AND PRECIPITABLE WATER VALUES LESS THAN ONE QUARTER INCH KEEP EVEN
CLOUDS OUT OF THE MIX FOR THE MOST PART.
A SECONDARY SHORTWAVE EMBEDDED IN THE MEAN FLOW WILL REINFORCE THE
COLD AIR THURSDAY WITH 850MB VALUES ACTUALLY DROPPING TO JUST BELOW
ZERO DEGREES C. THE TIMING OF THE COLD AIR ADVECTION IS CRITICAL AS
THE MET IS A LITTLE QUICKER AND HENCE HIGH TEMPERATURES IN THE
GUIDANCE BULLETINS ARE ABOUT A CATEGORY COOLER. THE FORECAST
CONTINUES TO OPT FOR A BLEND. FRIDAY MORNING WILL BE QUITE COOL WITH
MOST AREAS SEEING MID TO UPPER 20S.
&&
.LONG TERM /FRIDAY THROUGH MONDAY/...
AS OF 3 AM TUESDAY...THE MEDIUM RANGE GUIDANCE APPEARS TO BE COMING INTO
BETTER AGREEMENT WITH THE SCENARIO FOR THE WEEKEND. A SOMEWHAT DEEP
ALBEIT PROGRESSIVE MID LEVEL TROUGH WILL MOVE OUT FROM THE SOUTHWEST
AND ATTEMPT TO PHASE WITH A MODEST SYSTEM TO THE NORTH. THIS ALLOWS
A COMPLEX AREA OF LOW PRESSURE TO DEVELOP IN THE SOUTHEAST AND MOVE
UP THE COAST...EVENTUALLY REDEVELOPING OFF THE DELMARVA AND
DEEPENING. THE GFS CONTINUES TO BE A LITTLE FASTER OF THE GUIDANCE
AND HAVE INCREASED POPS TO MATCH ADJACENT OFFICES BETTER BUT OVERALL
THE LIONS SHARE OF POPS/QPF WILL OCCUR SATURDAY INTO SUNDAY MORNING.
HAVE TRIMMED BACK POPS FOR LATER SUNDAY FOR THE SAME REASONS. NO
CHANGES TO TEMPERATURE FORECAST.
&&
.AVIATION /12Z TUESDAY THROUGH SATURDAY/...
AS OF 12Z...AN AREA OF PRE-FRONTAL SHOWERS IS ALONG THE I-95
CORRIDOR...MOVING SLOWLY EAST. THE HRRR MODEL HAS THIS BATCH OF
SHOWERS MOVING OUR OF THE REGION LATER THIS MORNING...REPLACE WITH
ANOTHER BATCH OF CONVECTION ALONG THE FRONT BY EARLY AFTERNOON.
CONDITIONS AHEAD OF THE FRONT WILL LIKELY BOUNCE AROUND BOTH
VISIBILITIES AND CEILINGS. FRONT WILL MOVE THROUGH THE INLAND
TERMINALS BY EARLY AFTERNOON...THE COAST BY LATE AFTERNOON. POST
FRONTAL...EXPECT A WIND SHIFT TO THE NORTH NORTHWEST...GUSTY WITH
IMPROVING CONDITIONS. AN MVFR CEILING MAY BRIEFLY
OCCUR...PREDOMINATELY VFR THROUGH THE END OF THE FORECAST PERIOD.
EXTENDED OUTLOOK...INCREASING CONFIDENCE FOR VFR WEDNESDAY THROUGH
FRIDAY. SHOWERS POSSIBLE SATURDAY AHEAD OF AN APPROACHING LOW
PRESSURE SYSTEM.
&&
.MARINE...
NEAR TERM /THROUGH TONIGHT/...
AS OF 6:45 AM TUESDAY...CANCELED DENSE FOG ADVISORY EARLY.
OTHERWISE FORECAST CONTINUES WITHOUT CHANGES. PREVIOUS DISCUSSION
FOLLOWS:
SMALL CRAFT ADVISORY REMAINS IN EFFECT TODAY AS WINDS AND SEAS
INCREASE IN ADVANCE OF A STRONG COLD FRONT. WINDS WILL TURN
NORTHWEST THIS AFTERNOON AS THE FRONT MOVES ACROSS THE
WATERS...WITH LIMITED FETCH CAUSING NEAR-SHORE SEAS TO SUBSIDE TO
BELOW SMALL CRAFT ADVISORY CRITERIA TONIGHT. CURRENT OBS SHOW
CONDITIONS OVER THE COASTAL WATERS ARE STILL ON THE BENIGN
SIDE...WITH SW WINDS OF ONLY AROUND 5 KTS...AND 3 TO 4 FT SEAS.
SHORT TERM /WEDNESDAY THROUGH THURSDAY/...
AS OF 3 AM TUESDAY...OVERALL CONDITIONS NOT TOO BAD CONSIDERING HIGH
PRESSURE WILL BE MOVING IN FROM THE WEST/NORTHWEST. FOR
WEDNESDAY...WINDS WILL BE FROM THE NORTHEAST AROUND TEN KNOTS AND
MAY BE LOWER AS THE PATTERN BRIEFLY RELAXES LATE IN THE DAY. COLD
AIR ADVECTION DEVELOPS AGAIN THURSDAY WHICH WILL KICK WINDS UP TO
15-20 KNOTS FROM THE NORTH. SEAS WILL BE REFLECTIVE OF THE
WINDS...1-3 FEET MOST OF WEDNESDAY INTO EARLY THURSDAY INCREASING
WITH THE WINDS TO 3-5 FEET LATE IN THE PERIOD.
LONG TERM /FRIDAY THROUGH SATURDAY/...
AS OF 3 AM TUESDAY...EXPECT RELATIVELY BENIGN WINDS AND SEAS FOR
FRIDAY AS THE CENTER OF HIGH PRESSURE MOVES OVERHEAD. WINDS
INCREASE AND VEER MORE TO THE SOUTHEAST AS A STORM SYSTEM DEVELOPS
IN THE SOUTHEAST. STILL A LOT OF DETAILS TO IRON OUT WITH THIS
SYSTEM BUT OVERALL MARINERS SHOULD EXPECT THIS TREND OF INCREASING
WINDS AND SEAS FOR SATURDAY.
&&
.ILM WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
NC...NONE.
MARINE...SMALL CRAFT ADVISORY UNTIL 7 PM EST THIS EVENING FOR AMZ250-
252-254-256.
&&
$$
SYNOPSIS...SHK
NEAR TERM...REK
SHORT TERM...SHK
LONG TERM...SHK
AVIATION...DL
MARINE...REK/SHK
AREA FORECAST DISCUSSION
NWS WILMINGTON NC
633 AM EST TUE DEC 10 2013
.SYNOPSIS...
A COLD FRONT WILL SLOWLY MOVE ACROSS THE AREA TODAY BRINGING
WIDESPREAD LIGHT RAINFALL. DRY AND COOL CONDITIONS WILL DEVELOP
WEDNESDAY AND CONTINUE THROUGH FRIDAY. THE WEEKEND IS LOOKING MORE
AND MORE UNSETTLED AS A STORM SYSTEM DEVELOPS IN THE SOUTHEAST.
COOLER AND DRIER CONDITIONS ARE EXPECTED EARLY NEXT WEEK.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 3 AM TUESDAY...QUASI-STATIONARY FRONT WAVERING ACROSS THE
FORECAST AREA WILL PUSH OFFSHORE AS A COLD FRONT THIS AFTERNOON AS A
STRONG COLD SURGE BARRELS SOUTHEAST ACROSS THE EASTERN CAROLINAS.
TEMPERATURES WILL PEAK LATE THIS MORNING IN THE LOWER TO MID 60S
BEFORE A STRONG COLD ADVECTIVE REGIME SETS UP AND DROPS READINGS
BACK INTO THE 50S. LIGHT WINDS AND CLEARING SKIES OVERNIGHT WILL
COMBINE WITH CONTINUED COLD ADVECTION TO ALLOW MINIMUM TEMPERATURES
TO DIP INTO THE LOWER TO MID 30S.
PATCHY LIGHT RAIN AND DRIZZLE ARE CURRENTLY MOVING NORTHEAST ACROSS
OUR INLAND COUNTIES ALONG THE FRONTAL BOUNDARY. THE RAIN SHIELD WILL
SPREAD SOUTHEAST ACROSS THE FORECAST AREA THIS MORNING AS THE COLD
FRONT CONSOLIDATES AND DROPS SOUTHEAST. SHOWER ACTIVITY SHOULD END
BY AROUND MID AFTERNOON AS THE FRONT MOVES WELL OFFSHORE.
&&
.SHORT TERM /WEDNESDAY THROUGH THURSDAY NIGHT/...
AS OF 3 AM TUESDAY...THE MID LEVEL PATTERN WILL CONSIST OF AN INITIAL
WESTERLY FLOW TRANSITIONING INTO MORE OF A NORTHWEST FLOW THURSDAY.
THE ONLY FORECAST DILEMMA IS TEMPERATURES AS SURFACE HIGH PRESSURE
AND PRECIPITABLE WATER VALUES LESS THAN ONE QUARTER INCH KEEP EVEN
CLOUDS OUT OF THE MIX FOR THE MOST PART.
A SECONDARY SHORTWAVE EMBEDDED IN THE MEAN FLOW WILL REINFORCE THE
COLD AIR THURSDAY WITH 850MB VALUES ACTUALLY DROPPING TO JUST BELOW
ZERO DEGREES C. THE TIMING OF THE COLD AIR ADVECTION IS CRITICAL AS
THE MET IS A LITTLE QUICKER AND HENCE HIGH TEMPERATURES IN THE
GUIDANCE BULLETINS ARE ABOUT A CATEGORY COOLER. THE FORECAST
CONTINUES TO OPT FOR A BLEND. FRIDAY MORNING WILL BE QUITE COOL WITH
MOST AREAS SEEING MID TO UPPER 20S.
&&
.LONG TERM /FRIDAY THROUGH MONDAY/...
AS OF 3 AM TUESDAY...THE MEDIUM RANGE GUIDANCE APPEARS TO BE COMING INTO
BETTER AGREEMENT WITH THE SCENARIO FOR THE WEEKEND. A SOMEWHAT DEEP
ALBEIT PROGRESSIVE MID LEVEL TROUGH WILL MOVE OUT FROM THE SOUTHWEST
AND ATTEMPT TO PHASE WITH A MODEST SYSTEM TO THE NORTH. THIS ALLOWS
A COMPLEX AREA OF LOW PRESSURE TO DEVELOP IN THE SOUTHEAST AND MOVE
UP THE COAST...EVENTUALLY REDEVELOPING OFF THE DELMARVA AND
DEEPENING. THE GFS CONTINUES TO BE A LITTLE FASTER OF THE GUIDANCE
AND HAVE INCREASED POPS TO MATCH ADJACENT OFFICES BETTER BUT OVERALL
THE LIONS SHARE OF POPS/QPF WILL OCCUR SATURDAY INTO SUNDAY MORNING.
HAVE TRIMMED BACK POPS FOR LATER SUNDAY FOR THE SAME REASONS. NO
CHANGES TO TEMPERATURE FORECAST.
&&
.AVIATION /12Z TUESDAY THROUGH SATURDAY/...
AS OF 12Z...AN AREA OF PRE-FRONTAL SHOWERS IS ALONG THE I-95
CORRIDOR...MOVING SLOWLY EAST. THE HRRR MODEL HAS THIS BATCH OF
SHOWERS MOVING OUR OF THE REGION LATER THIS MORNING...REPLACE WITH
ANOTHER BATCH OF CONVECTION ALONG THE FRONT BY EARLY AFTERNOON.
CONDITIONS AHEAD OF THE FRONT WILL LIKELY BOUNCE AROUND BOTH
VISIBILITIES AND CEILINGS. FRONT WILL MOVE THROUGH THE INLAND
TERMINALS BY EARLY AFTERNOON...THE COAST BY LATE AFTERNOON. POST
FRONTAL...EXPECT A WIND SHIFT TO THE NORTH NORTHWEST...GUSTY WITH
IMPROVING CONDITIONS. AN MVFR CEILING MAY BRIEFLY
OCCUR...PREDOMINATELY VFR THROUGH THE END OF THE FORECAST PERIOD.
EXTENDED OUTLOOK...INCREASING CONFIDENCE FOR VFR WEDNESDAY THROUGH
FRIDAY. SHOWERS POSSIBLE SATURDAY AHEAD OF AN APPROACHING LOW
PRESSURE SYSTEM.
&&
.MARINE...
NEAR TERM /THROUGH TONIGHT/...
AS OF 3 AM TUESDAY...SMALL CRAFT ADVISORY REMAINS IN EFFECT TODAY
AS WINDS AND SEAS INCREASE IN ADVANCE OF A STRONG COLD FRONT. WINDS
WILL TURN NORTHWEST THIS AFTERNOON AS THE FRONT MOVES ACROSS THE
WATERS...WITH LIMITED FETCH CAUSING NEAR-SHORE SEAS TO SUBSIDE TO
BELOW SMALL CRAFT ADVISORY CRITERIA TONIGHT. CURRENT OBS SHOW
CONDITIONS OVER THE COASTAL WATERS ARE STILL ON THE BENIGN
SIDE...WITH SW WINDS OF ONLY AROUND 5 KTS...AND 3 TO 4 FT SEAS.
SHORT TERM /WEDNESDAY THROUGH THURSDAY/...
AS OF 3 AM TUESDAY...OVERALL CONDITIONS NOT TOO BAD CONSIDERING HIGH
PRESSURE WILL BE MOVING IN FROM THE WEST/NORTHWEST. FOR
WEDNESDAY...WINDS WILL BE FROM THE NORTHEAST AROUND TEN KNOTS AND
MAY BE LOWER AS THE PATTERN BRIEFLY RELAXES LATE IN THE DAY. COLD
AIR ADVECTION DEVELOPS AGAIN THURSDAY WHICH WILL KICK WINDS UP TO
15-20 KNOTS FROM THE NORTH. SEAS WILL BE REFLECTIVE OF THE
WINDS...1-3 FEET MOST OF WEDNESDAY INTO EARLY THURSDAY INCREASING
WITH THE WINDS TO 3-5 FEET LATE IN THE PERIOD.
LONG TERM /FRIDAY THROUGH SATURDAY/...
AS OF 3 AM TUESDAY...EXPECT RELATIVELY BENIGN WINDS AND SEAS FOR
FRIDAY AS THE CENTER OF HIGH PRESSURE MOVES OVERHEAD. WINDS
INCREASE AND VEER MORE TO THE SOUTHEAST AS A STORM SYSTEM DEVELOPS
IN THE SOUTHEAST. STILL A LOT OF DETAILS TO IRON OUT WITH THIS
SYSTEM BUT OVERALL MARINERS SHOULD EXPECT THIS TREND OF INCREASING
WINDS AND SEAS FOR SATURDAY.
&&
.ILM WATCHES/WARNINGS/ADVISORIES...
SC...DENSE FOG ADVISORY UNTIL 6 AM EST EARLY THIS MORNING FOR
SCZ017-023-024-032-033-039-053>056.
NC...DENSE FOG ADVISORY UNTIL 6 AM EST EARLY THIS MORNING FOR
NCZ087-096-099-105>110.
MARINE...DENSE FOG ADVISORY UNTIL 6 AM EST EARLY THIS MORNING FOR
AMZ250-252-254-256.
SMALL CRAFT ADVISORY UNTIL 7 PM EST THIS EVENING FOR AMZ250-
252-254-256.
&&
$$
SYNOPSIS...SHK
NEAR TERM...REK
SHORT TERM...SHK
LONG TERM...SHK
AVIATION...43
AREA FORECAST DISCUSSION
NWS CHARLESTON WV
434 AM EST TUE DEC 10 2013
.SYNOPSIS...
WEAK SYSTEM EARLY TODAY WITH SOME SNOW. CHILLY DRY HIGH PRESSURE
WEDNESDAY. ARCTIC FRONT WEDNESDAY NIGHT. ARCTIC HIGH PRESSURE
THURSDAY EXITS FRIDAY. ANOTHER SYSTEM THIS WEEKEND.
&&
.NEAR TERM /THROUGH TONIGHT/...
1230 AM UPDATE...
FORECAST ESSENTIALLY ON TRACK AT THIS POINT. ONE FORECASTED BAND
OF SNOW LOCATED OUT TO OUR WEST OVER CENTRAL/SW OHIO STILL
PROGRESSING SLOWLY TOWARDS OUR SE OHIO ZONES...WITH MORE PRECIP TO
THE SOUTHWEST INTO SE KY AND NORTHEAST TENN AT THIS TIME. WEAK
ECHOES SHOWING UP OVERHEAD HERE ON KRLX RADAR BUT VAD PROFILE
SHOWING THAT INITIAL PRECIP WILL FIRST HAVE SOME DRY AIR LOWER
LEVELS TO OVERCOME...WHICH IT WILL EVENTUALLY DO. STILL ALSO
WATCHING FOR ANY BANDING SETTING UP OVER OUR AREA OR TO OUR SW TO
HOPEFULLY PINPOINT ANY TARGET AREAS.
10 PM UPDATE...UPDATED SNOW GRIDS BASED ON CURRENT MODEL RUNS.
MADE LITTLE CHANGES TO OVERALL TOTALS. STILL LOOKING AT 1 TO 2
ACROSS MUCH OF THE NORTH...WITH 2 TO 4 ACROSS CENTRAL AND NORTHERN
WV LOWLANDS...AND 2 TO 5 AS A GENERAL RULE ACROSS THE MOUNTAINS.
NEW MODEL RUNS STARTING TO HIT HARDER ON QPF FOR BAND OF SNOWFALL
ACROSS SOUTHEAST OHIO THIS EVENING. AT THIS POINT...DID UP
SNOWFALL TOTALS...BUT KEPT BELOW ADVISORY CRITERIA AT THIS POINT.
WILL ALLOW THE MIDNIGHT SHIFT TO KEEP AN EYE ON AND ADD AN
ADVISORY TO THESE AREAS IF NEED BE.
PREVIOUS DISCUSSION FOLLOWS...
KEPT SOME DZ IN WX GRIDS A FEW MORE HRS THIS AFTN ALONG AND E OF
I79 CORRIDOR. THINK THE LOW CRUD STRATUS HOLDS INTO THE OVERNIGHT
ACROSS THE LOWLANDS AND PORTIONS OF THE MTNS. MAY SEE SOME BREAKS
ACROSS NE KY/SE OH AND W LOWLANDS BEFORE FILLING BACK IN LATE
AHEAD OF THE NEXT SYSTEM. TEMPS WILL GRADUALLY FALL TONIGHT WITH
POTENTIAL FOR SOME PATCHY BLACK ICE FOR ANY UNTREATED SURFACES
THAT HAVE LINGERING MOISTURE.
NOW FOR UPCOMING SYSTEM. GFS...NAM AND 00Z RUNS OF HI RESOLUTION
WRFS DEPICT A BAND OF ADVISORY LEVEL SNOW FROM NEAR MT STERLING TO
HUNTINGTON...NE THRU CHARLESTON...CLARKSBURG AND N MTNS. THE
SREF...GEM...AND RUC WOULD HAVE THE HIGHER QPF FURTHER E...CLOSER TO
THE BAROCLINIC ZONE. THIS CREATES TWO CAMPS REGARDING SNOW ACCUMS
WITH ADVISORY LEVEL SNOW FROM THE LATTER GROUP PRIMARILY ACROSS THE
MOUNTAINS. HPC WWD ALSO NOTED THIS SPLIT IN THEIR WINTER QPF GRIDS.
WILL TRY TO TAKE A BLEND WITH THIS WHICH WOULD WARRANT ADVISORIES
FOR ALL OF WV COUNTIES ALONG WITH SW VA AND PORTIONS OF NE KY. THERE
IS ENOUGH AGREEMENT TO LEAVE OUT SE OH AS THIS AREA MAY BE BETWEEN
SFC WAVE AND BAND FROM UPPER LEVEL TROF AS WELL AS GREENUP AND
CARTER AND NEW 18Z NAM ROLLING HAS SHIFTED E MORE IN LINE WITH
SREF/CMC/RUC. NONETHELESS HAVE ISSUED HEADLINES RUNNING FROM 06Z TO
20Z ALTHOUGH THE END TIME MAY BE ABLE TO DROP EARLY.
APPEARS HIGHER AMOUNTS WOULD BE ACROSS THE N LOWLANDS AND N MTNS AS
THE UPPER TROF APPROACHES TO HELP IN SOME MESOSCALE BANDING VIA SOME
SLANTWISE INSTABILITY AND JET DYNAMICS. THIS IS WHERE SOME 2 TO 4
WAS CODED UP FOR C AND N LOWLANDS WITH 3 TO 6 FOR N MOUNTAINS. 1 TO
3 S WV/SW VA WITH LESS THAN AN INCH SE OH TO OH RIVR. BAND WITH THE
UPPER TROF LOOKS TO AFFECT N REACHES OF SE OH COUNTIES...IE
PERRY/MORGAN. ALSO SE WV/BKW...AND SW VA...THERMAL PROFILES INDICATE
POTENTIAL FOR A MIX.
UPPER SYS AND SFC WAVE QUICKLY PULLS E BY 18Z WITH SOME PARTIAL
CLEARING ACROSS SE OH INTO NE KY. HAVE KEPT TEMPS BELOW FREEZING ALL
LOCATIONS TOMORROW WITH ONLY A MODEST REBOUND AFTER THE SNOW MOVES
OUT.
&&
.SHORT TERM /WEDNESDAY THROUGH THURSDAY NIGHT/...
SURFACE HIGH PRESSURE BUILDS IN FROM THE WEST PREVAILING THROUGH
THE PERIOD.
ZONAL FLOW ALOFT WILL PROVIDE FOR DRY WEATHER WEDNESDAY THROUGH
THURSDAY NIGHT. MODELS SUGGEST A SHORTWAVE...EVIDENT IN H5
VORTICITY MAX RIDING IN A LOW AMPLITUDE TROUGH REACHING EXTREME
NORTHERN WV BY 06Z THURSDAY. THIS CLIPPER SYSTEM WILL REINFORCE
THE COLD AIR BY WEDNESDAY NIGHT.
LIMITED MOISTURE WILL PROVIDE FOR PLENTY OF CLOUDS...AND SNOW
SHOWERS LIMITED TO UPSLOPE IN THE MOUNTAINS MAINLY IN THE COLD
ADVECTION WNW FLOW ONCE THE FRONT PASSES OVERNIGHT WED NT. ARCTIC
HIGH PRESSURE BUILDS IN ON THU.
HIGHS FOR WEDNESDAY WILL REMAIN AT OR BELOW FREEZING FOR THE MOST
PART. MODELS SHOW COLD AIR ADVECTION AT H85 CONTINUING AS FLOW
TURNS NORTHWEST REACHING MINUS 18C BY 12Z THURSDAY.
THEREFORE...EXPECT LOWS INTO THE TEENS FOR THE MOST PART FOR LOWS
WEDNESDAY NIGHT INTO EARLY THURSDAY MORNING.
THE COLD AIR WILL REMAIN IN PLACE THURSDAY FOR EVEN COLDER
TEMPERATURES FOR HIGHS...MAINLY IN THE 20S LOWLANDS...RANGING INTO
THE TEENS HIGHEST ELEVATIONS.
USED A MIXTURE OF GUIDANCE FOR TEMPERATURES THROUGH THE PERIOD.
CLOSER TO THE COLDEST GFS WEDNESDAY AND WEDNESDAY NIGHT. FOR
THURSDAY STAYED CLOSER TO THE CONSENSUS MOS.
&&
.LONG TERM /FRIDAY THROUGH MONDAY/...
MODELS SHOWING AN INTERESTING SYSTEM FOR SATURDAY INTO SUNDAY...WITH
POTENTIAL WINTER WEATHER ON THE ONSET. STILL LOTS OF SPREAD IN THE
MODELS HOWEVER...SO WOULD NOT PUT MUCH STOCK IN THE DETAILS AT THIS
TIME. USED A BLEND OF THE GEFS MEAN/ECMWF MEAN/GFS AND ECMWF.
&&
.AVIATION /09Z TUESDAY THROUGH SATURDAY/...
00Z TUESDAY THROUGH 00Z WEDNESDAY
PRIMARILY MVFR STRATUS TONIGHT WITH SOME IFR CIGS/VSBY IN THE
MOUNTAINS AMID PATCHY DZ.
AN UPPER DISTURBANCE WILL MOVE INTO THE REGION LATE TONIGHT...WITH
SNOW DEVELOPING ACROSS THE AREA GENERALLY AROUND THE 07Z-08Z TIME
FRAME. BULK OF PRECIPITATION WILL GENERALLY BE ALONG AND SOUTH/EAST OF
A LINE FROM CKB TO CRW TO HTS...THOUGH LOCATIONS FURTHER NORTH AND
WEST WILL LIKELY SEE SOME SNOW AS WELL. EXPECT WIDESPREAD IFR AND LIFR
CONDITIONS IN SNOW.
SNOW WILL GRADUALLY TAPER OFF FROM WEST TO EAST AFTER 15Z
TUESDAY...WITH A GRADUAL RETURN TO MVFR CONDITIONS...WITH SOME
IMPROVEMENT TO VFR GENERALLY AFTER 18Z ACROSS THE WEST...AND
PERHAPS 21Z FOR EASTERN TERMINALS SUCH AS CKB-BKW-EKN.
FORECAST CONFIDENCE AND ALTERNATE SCENARIOS THROUGH 06Z WEDNESDAY...
FORECAST CONFIDENCE: MEDIUM.
ALTERNATE SCENARIOS: TIMING OF IFR/LIFR CIGS MAY VARY FROM CURRENT
FORECAST. TIMING AND INTENSITY OF SNOW AND VIS FROM SNOWFALL RATES
MAY VARY.
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.
DATE TUE 12/10/13
UTC 1HRLY 08 09 10 11 12 13 14 15 16 17 18 19
EST 1HRLY 03 04 05 06 07 08 09 10 11 12 13 14
CRW CONSISTENCY H M M M M M H H H H M M
HTS CONSISTENCY H M H M M M H H H H H M
BKW CONSISTENCY M M M M M H H M M H H M
EKN CONSISTENCY L L M M M M M M M L L L
PKB CONSISTENCY H H H M M M L L L H H M
CKB CONSISTENCY H H M M M M M M L L L H
AFTER 06Z WEDNESDAY...
IFR POSSIBLE IN SNOW...SLEET...FREEZING RAIN AND RAIN SATURDAY AND SUNDAY.
&&
.RLX WATCHES/WARNINGS/ADVISORIES...
WV...WINTER WEATHER ADVISORY UNTIL 3 PM EST THIS AFTERNOON FOR
WVZ005>011-013>020-024>040-046-047.
OH...NONE.
KY...WINTER WEATHER ADVISORY UNTIL 3 PM EST THIS AFTERNOON FOR
KYZ103-105.
VA...WINTER WEATHER ADVISORY UNTIL 3 PM EST THIS AFTERNOON FOR
VAZ003-004.
&&
$$
SYNOPSIS...TRM/RPY/30
NEAR TERM...ARJ
SHORT TERM...TRM
LONG TERM...RPY
AVIATION...50
AREA FORECAST DISCUSSION
NWS CHARLESTON WV
1249 AM EST TUE DEC 10 2013
.SYNOPSIS...
WEAK SYSTEM LATE TONIGHT INTO TUESDAY WITH SOME SNOW. CHILLY DRY
HIGH PRESSURE WEDNESDAY. ARCTIC FRONT WEDNESDAY NIGHT. ARCTIC HIGH
PRESSURE THURSDAY EXITS FRIDAY. ANOTHER SYSTEM THIS WEEKEND.
&&
.NEAR TERM /THROUGH TODAY/...
1230 AM UPDATE...
FORECAST ESSENTIALLY ON TRACK AT THIS POINT. ONE FORECASTED BAND
OF SNOW LOCATED OUT TO OUR WEST OVER CENTRAL/SW OHIO STILL
PROGRESSING SLOWLY TOWARDS OUR SE OHIO ZONES...WITH MORE PRECIP TO
THE SOUTHWEST INTO SE KY AND NORTHEAST TENN AT THIS TIME. WEAK
ECHOES SHOWING UP OVERHEAD HERE ON KRLX RADAR BUT VAD PROFILE
SHOWING THAT INITIAL PRECIP WILL FIRST HAVE SOME DRY AIR LOWER
LEVELS TO OVERCOME...WHICH IT WILL EVENTUALLY DO. STILL ALSO
WATCHING FOR ANY BANDING SETTING UP OVER OUR AREA OR TO OUR SW TO
HOPEFULLY PINPOINT ANY TARGET AREAS.
10 PM UPDATE...UPDATED SNOW GRIDS BASED ON CURRENT MODEL RUNS.
MADE LITTLE CHANGES TO OVERALL TOTALS. STILL LOOKING AT 1 TO 2
ACROSS MUCH OF THE NORTH...WITH 2 TO 4 ACROSS CENTRAL AND NORTHERN
WV LOWLANDS...AND 2 TO 5 AS A GENERAL RULE ACROSS THE MOUNTAINS.
NEW MODEL RUNS STARTING TO HIT HARDER ON QPF FOR BAND OF SNOWFALL
ACROSS SOUTHEAST OHIO THIS EVENING. AT THIS POINT...DID UP
SNOWFALL TOTALS...BUT KEPT BELOW ADVISORY CRITERIA AT THIS POINT.
WILL ALLOW THE MIDNIGHT SHIFT TO KEEP AN EYE ON AND ADD AN
ADVISORY TO THESE AREAS IF NEED BE.
PREVIOUS DISCUSSION FOLLOWS...
KEPT SOME DZ IN WX GRIDS A FEW MORE HRS THIS AFTN ALONG AND E OF
I79 CORRIDOR. THINK THE LOW CRUD STRATUS HOLDS INTO THE OVERNIGHT
ACROSS THE LOWLANDS AND PORTIONS OF THE MTNS. MAY SEE SOME BREAKS
ACROSS NE KY/SE OH AND W LOWLANDS BEFORE FILLING BACK IN LATE
AHEAD OF THE NEXT SYSTEM. TEMPS WILL GRADUALLY FALL TONIGHT WITH
POTENTIAL FOR SOME PATCHY BLACK ICE FOR ANY UNTREATED SURFACES
THAT HAVE LINGERING MOISTURE.
NOW FOR UPCOMING SYSTEM. GFS...NAM AND 00Z RUNS OF HI RESOLUTION
WRFS DEPICT A BAND OF ADVISORY LEVEL SNOW FROM NEAR MT STERLING TO
HUNTINGTON...NE THRU CHARLESTON...CLARKSBURG AND N MTNS. THE
SREF...GEM...AND RUC WOULD HAVE THE HIGHER QPF FURTHER E...CLOSER TO
THE BAROCLINIC ZONE. THIS CREATES TWO CAMPS REGARDING SNOW ACCUMS
WITH ADVISORY LEVEL SNOW FROM THE LATTER GROUP PRIMARILY ACROSS THE
MOUNTAINS. HPC WWD ALSO NOTED THIS SPLIT IN THEIR WINTER QPF GRIDS.
WILL TRY TO TAKE A BLEND WITH THIS WHICH WOULD WARRANT ADVISORIES
FOR ALL OF WV COUNTIES ALONG WITH SW VA AND PORTIONS OF NE KY. THERE
IS ENOUGH AGREEMENT TO LEAVE OUT SE OH AS THIS AREA MAY BE BETWEEN
SFC WAVE AND BAND FROM UPPER LEVEL TROF AS WELL AS GREENUP AND
CARTER AND NEW 18Z NAM ROLLING HAS SHIFTED E MORE IN LINE WITH
SREF/CMC/RUC. NONETHELESS HAVE ISSUED HEADLINES RUNNING FROM 06Z TO
20Z ALTHOUGH THE END TIME MAY BE ABLE TO DROP EARLY.
APPEARS HIGHER AMOUNTS WOULD BE ACROSS THE N LOWLANDS AND N MTNS AS
THE UPPER TROF APPROACHES TO HELP IN SOME MESOSCALE BANDING VIA SOME
SLANTWISE INSTABILITY AND JET DYNAMICS. THIS IS WHERE SOME 2 TO 4
WAS CODED UP FOR C AND N LOWLANDS WITH 3 TO 6 FOR N MOUNTAINS. 1 TO
3 S WV/SW VA WITH LESS THAN AN INCH SE OH TO OH RIVR. BAND WITH THE
UPPER TROF LOOKS TO AFFECT N REACHES OF SE OH COUNTIES...IE
PERRY/MORGAN. ALSO SE WV/BKW...AND SW VA...THERMAL PROFILES INDICATE
POTENTIAL FOR A MIX.
UPPER SYS AND SFC WAVE QUICKLY PULLS E BY 18Z WITH SOME PARTIAL
CLEARING ACROSS SE OH INTO NE KY. HAVE KEPT TEMPS BELOW FREEZING ALL
LOCATIONS TOMORROW WITH ONLY A MODEST REBOUND AFTER THE SNOW MOVES
OUT.
&&
.SHORT TERM /TONIGHT THROUGH THURSDAY/...
HAVING TRANSITIONED TO ZONAL UPPER LEVEL FLOW FROM SW JUST PRIOR TO
THE START OF THIS PERIOD...THE FLOW TRANSITIONS FARTHER...TO WNW TO
NW...AS L/W TROUGHING MOVES FROM THE CENTER OF THE CONTINENT TO THE
EASTERN HALF.
FLURRIES IN THE COLD ADVECTION UPSLOPE WNW LOW LEVEL FLOW RIGHT AT
THE START OPF THE PERIOD...WIND DOWN OVERNIGHT...AS HIGH PRESSURE
BUILDS INTO THE S. A CLIPPER SYSTEM / ARCTIC FRONT MOVES THROUGH
LATE WED NT...REINFORCING THE COLD AIR. SNOW SHOWERS WITH THIS
MOISTURE STARVED SYSTEM WILL BE LIMITED TO UPSLOPE IN THE MOUNTAINS
MAINLY IN THE COLD ADVECTION WNW FLOW ONCE THE FRONT PASSES
OVERNIGHT WED NT. ARCTIC HIGH PRESSURE BUILDS IN ON THU.
TEMPERATURES TEN TO FIFTEEN DEGREES BELOW NORMAL THIS PERIOD.
LOWS TUE NT LOOKED GOOD WITH MINOR CHANGES ONLY. BLENDED IN BIAS
CORRECTED ADJMET FOR HIGHS WED...A LITTLE LOWER IN THE N. BLENDED
IN BIAS CORRECTED CONSENSUS MOS FOR LOWS WED NT...A LITTLE HIGHER
WITH CLIPPER COMING THROUGH EXCEPT LITTLE OR NO CHANGE NW IN THE
WAKE OF THE CLIPPER. BLENDED IN ADJMEX AND BIAS CORRECTED
ECMWFHIRES FOR LOWER HIGHS IN THE ARCTIC AIR ON THU.
&&
.LONG TERM /THURSDAY NIGHT THROUGH MONDAY/...
MODELS SHOWING AN INTERESTING SYSTEM FOR SATURDAY INTO SUNDAY...WITH
POTENTIAL WINTER WEATHER ON THE ONSET. STILL LOTS OF SPREAD IN THE
MODELS HOWEVER...SO WOULD NOT PUT MUCH STOCK IN THE DETAILS AT THIS
TIME. USED A BLEND OF THE GEFS MEAN/ECMWF MEAN/GFS AND ECMWF.
&&
.AVIATION /06Z TUESDAY THROUGH SATURDAY/...
00Z TUESDAY THROUGH 00Z WEDNESDAY
PRIMARILY MVFR STRATUS TONIGHT WITH SOME IFR CIGS/VSBY IN THE
MOUNTAINS AMID PATCHY DZ.
AN UPPER DISTURBANCE WILL MOVE INTO THE REGION LATE TONIGHT...WITH
SNOW DEVELOPING ACROSS THE AREA GENERALLY AROUND THE 07Z-08Z TIME
FRAME. BULK OF PRECIPITATION WILL GENERALLY BE ALONG AND SOUTH/EAST OF
A LINE FROM CKB TO CRW TO HTS...THOUGH LOCATIONS FURTHER NORTH AND
WEST WILL LIKELY SEE SOME SNOW AS WELL. EXPECT WIDESPREAD IFR AND LIFR
CONDITIONS IN SNOW.
SNOW WILL GRADUALLY TAPER OFF FROM WEST TO EAST AFTER 15Z
TUESDAY...WITH A GRADUAL RETURN TO MVFR CONDITIONS...WITH SOME
IMPROVEMENT TO VFR GENERALLY AFTER 18Z ACROSS THE WEST...AND
PERHAPS 21Z FOR EASTERN TERMINALS SUCH AS CKB-BKW-EKN.
FORECAST CONFIDENCE AND ALTERNATE SCENARIOS THROUGH 06Z WEDNESDAY...
FORECAST CONFIDENCE: MEDIUM.
ALTERNATE SCENARIOS: TIMING OF IFR/LIFR CIGS MAY VARY FROM CURRENT
FORECAST. TIMING AND INTENSITY OF SNOW AND VIS FROM SNOWFALL RATES
MAY VARY.
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.
DATE TUE 12/10/13
UTC 1HRLY 06 07 08 09 10 11 12 13 14 15 16 17
EST 1HRLY 01 02 03 04 05 06 07 08 09 10 11 12
CRW CONSISTENCY H H H M M M M M H H H H
HTS CONSISTENCY H H H M H M M M H H H H
BKW CONSISTENCY M M M M M H H M M M M H
EKN CONSISTENCY L L L L M M M M M M M L
PKB CONSISTENCY H H H H H M M M L L L H
CKB CONSISTENCY H H H H M M M M M M L L
AFTER 06Z WEDNESDAY...
IFR POSSIBLE IN SNOW...SLEET...FREEZING RAIN AND RAIN SATURDAY AND SUNDAY.
&&
.RLX WATCHES/WARNINGS/ADVISORIES...
WV...WINTER WEATHER ADVISORY UNTIL 3 PM EST THIS AFTERNOON FOR
WVZ005>011-013>020-024>040-046-047.
OH...NONE.
KY...WINTER WEATHER ADVISORY UNTIL 3 PM EST THIS AFTERNOON FOR
KYZ103-105.
VA...WINTER WEATHER ADVISORY UNTIL 3 PM EST THIS AFTERNOON FOR
VAZ003-004.
&&
$$
SYNOPSIS...TRM/RPY/30
NEAR TERM...50/SL/30
SHORT TERM...TRM
LONG TERM...RPY
AVIATION...50
AREA FORECAST DISCUSSION
NWS CLEVELAND OH
1150 PM EST MON DEC 9 2013
.SYNOPSIS...
A RIDGE OF HIGH PRESSURE WILL BUILD IN FROM THE SOUTHWEST TONIGHT. A
FAST MOVING LOW PRESSURE SYSTEM WILL MOVE EAST ACROSS THE NORTHERN
GREAT LAKES REGION TUESDAY WITH A REINFORCING ARCTIC COLD FRONT.
HIGH PRESSURE WILL BUILD EAST INTO THE OHIO VALLEY ON THURSDAY AND
TO THE EAST COAST ON FRIDAY.
&&
.NEAR TERM /UNTIL 6 AM TUESDAY MORNING/...
TWO AREAS OF CONCERN. ONE IS THE POTENTIAL FOR SOME LAKE EFFECT
SNOW FOR THE SNOW BELT AREA LATE TONIGHT. THE LAKE AND 850 MB
TEMPERATURE DIFFERENCE WILL BE NEAR 20C BY DAYBREAK TUESDAY. ONE
TO LOCALLY TWO INCHES OF SNOW MAY ACCUMULATE. SOME RIDGING WILL
HELP KEEP THE SNOWFALL AMOUNTS DOWN.
AN IMPULSE IN THE SOUTHWEST FLOW ALOFT WILL CAUSE SOME SNOW IN THE
SOUTHERN PORTION OF THE FORECAST AREA AFTER MIDNIGHT...THIS IS IN
THE RIGHT REAR QUAD OF THE JET. BASED ON THE RUC MODEL INCREASED THE
POPS A LITTLE. THE SNOWFALL AMOUNTS COULD BE AROUND AN INCH.
MADE MINOR ADJUSTMENTS TO THE LOWS BASED ON SOME CLOUDS AND WIND.
&&
.SHORT TERM /6 AM TUESDAY MORNING THROUGH THURSDAY NIGHT/...
SOME SNOW SHOWERS LINGERS IN THE SNOW BELT AS THE WINDS WILL
BECOME SOUTHWEST AND SHIFT THE BANDS INTO THE LAKE. THE SNOW/SNOW
SHOWERS OVER THE SE PORTION OF THE FORECAST AREA WILL BE QUICKLY
MOVING OUT.
ANOTHER FRONT WILL BE MOVING THROUGH THE REGION ON TUESDAY AND THE
WINDS ALOFT NEAR THE FRONTAL BOUNDARY WILL BE NEAR 40 KNOTS.
ADDED GUSTS UP TO 40 MPH IN THE AFTERNOON. SOME BREAKS IN THE
CLOUDS WILL HELP BRING DOWN SOME OF THE WIND.
ALSO DEBATED ABOUT ISSUING A LAKE EFFECT WATCH FOR THE SNOW BELT
FOR LATE TUESDAY NIGHT INTO THURSDAY. WITH THE 18Z DATA STILL SOME
QUESTIONS ABOUT THE WIND DIRECTION AND THE AMOUNT OF MOISTURE. THE
GFS IS THE MOST PESSIMISTIC. THE CANADIAN MODEL IS VERY DRY. WITH
THAT WILL LET THE MID NIGHT SHIFT TAKE ANOTHER LOOK BEFORE ISSUING
OR NOT ISSUING THE LAKE EFFECT WATCH.
PREVIOUS DISCUSSION...
THE FIRST HALF OF TUESDAY WILL GENERALLY BE DRY AND
COOL UNDER THE INFLUENCE OF HIGH PRESSURE. BY TUESDAY EVENING THE
NEXT TROUGH ARRIVES AND LAKE EFFECT SNOW WILL SET UP ACROSS NW
PA/NE OH. WILL HOLD OFF ON A LAKE EFFECT SNOW WATCH FOR THIS
PACKAGE...WITH THE HEAVIEST SNOW NOT FALLING UNTIL OUTSIDE THE
THIRD PERIOD. LAKE EFFECT WILL WIND DOWN BY THURSDAY AFTERNOON.
MOST AREAS OUTSIDE OF THE SNOWBELT WILL BE DRY. WEDNESDAY NIGHT LOW
TEMPERATURES WILL DROP INTO THE SINGLE DIGITS BEHIND AN ARCTIC
COLD FRONT.
&&
.LONG TERM /FRIDAY THROUGH MONDAY/...
THE MODELS ARE A LITTLE MORE IN AGREEMENT THE SECOND HALF OF THE
WEEK WITH HIGH PRESSURE SLIDING EAST AND THE FLOW BACKING TO
SOUTHWEST BY FRIDAY. THIS WILL PUT AN END TO THE LAKE EFFECT THREAT.
TEMPERATURES SHOULD BOTTOM OUT ON THURSDAY AS SOME OF THE ARCTIC AIR
FILTERS ACROSS THE AREA. THE TREND UPWARD WILL BE RELATIVELY SLOW
AS MOST OF THE COUNTRY WILL BE TRYING TO MODIFY FROM ARCTIC AIR AND
OF COURSE THE SUN ANGLE IS AT A MINIMUM THIS TIME OF YEAR. FORECAST
HIGHS MOSTLY IN THE TEENS THURSDAY AND 20S ON FRIDAY.
STILL NO CONFIDENCE ON THE SCENARIO FOR SATURDAY. THE MODELS SHOW A
DECENT SHORT WAVE AND CORRESPONDING SURFACE LOW TRACKING FROM THE
SOUTH CENTRAL STATES AND ENDING UP ALONG THE MID ATLANTIC COAST.
THESE SYSTEMS OFTEN REDEVELOP FROM THE OHIO VALLEY TO THE EAST COAST
AND WE END UP IN THE TRANSITION ZONE SO NOT A LOT OF CONFIDENCE ON
THE STRENGTH AND TRACK OF THE SURFACE LOW YET. THE FORECAST WILL GO
FOR TEMPERATURES NEAR FREEZING ON SATURDAY AND A CHANCE OF SNOW. WE
MAY END UP NEEDING HIGHER POPS AND A MIX OF PRECIPITATION BUT WILL
WAIT TO SEE THE MODEL TRENDS THIS WEEK. COLDER AGAIN BY SUNDAY INTO
MONDAY AS THE PATTERN REMAINS COLD.
&&
.AVIATION /06Z TUESDAY THROUGH SATURDAY/...
A WEAK MID LEVEL SYSTEM WILL SPREAD SOME LIGHT SNOW OR FLURRIES ENE
ACROSS THE SOUTHERN HALF OF THE AREA FROM 07Z THRU ABOUT 13Z. CAK
MAY SEE 3 OR 4 HOURS OF IFR VSBYS WITH THE LIGHT SNOW...MFD AND YNG
WILL HAVE A LESSOR THREAT WHILE CLE SHOULD ONLY SEE A FEW FLURRIES
AT MOST.
ERI WILL KEEP AN ONGOING THREAT FOR SCT LIGHT SHSN AS LAKE EFFECT
CONDITIONS SET UP WITH MEAN LOW LEVEL WINDS HAVING JUST ENOUGH
ONSHORE COMPONENT FOR THE SNOW BANDS TO SPREAD INTO THE ERI AREA. AS
USUAL WITH LAKE EFFECT SHSN...EXPECT TO SEE HIGHLY VARIABLE
CONDITIONS AS THE ON AND OFF SHSN OCCUR.
AN AREA OF DRYER LOW LEVEL DRY AIR WORKS EAST ACROSS THE TAF SITES
AND LOOKS TO BE OVER TOL...FDY THRU MID MORNING AND OVER THE EASTERN
SITES EARLY TO MID AFTERNOON. ANY LEFTOVER MVFR AT MFD...CAK AND YNG
SHOULD LIFT TO VFR AS THE DRYER AIR MOVES IN. HOWEVER...AT ERI
CONDITIONS LOOK GOOD ENOUGH FOR LAKE EFFECT SHSN TO CONTINUE TO
PESTER THE AREA THRU THE DAY TUE AND TUE EVE OR AT LEAST BE ON THE
NORTH SIDE OF THE AIRSPACE.
WSW WINDS MAY GUST AROUND 20 KNOTS NEAR THE LAKESHORE TONIGHT THEN
INCREASE AGAIN LATER TUE MORNING INTO MID AFTERNOON TO BE GUSTING 25
TO 30 KNOTS WITH THE HIGHER GUSTS AT TOL AND FDY AND ALONG THE
LAKESHORE.
OUTLOOK...NON VFR CONDITIONS WILL LINGER AT TIMES THROUGH
THURSDAY...MAINLY OVER NE OH/NW PA.
&&
.MARINE...
ALLOWING GALE WARNING TO EXPIRE AS PLANNED AT 7 PM. IF WIND FORECAST
NEEDS TO BE INCREASED A LITTLE MORE WITH NEW 00Z DATA ON THE MID
SHIFT THEN WILL LIKELY NEED ANOTHER GALE FOR THE EAST HALF OF THE
LAKE FOR LATER TUE INTO TUE NIGHT. OTHERWISE...SCA CONDITIONS WILL
TEND TO PREVAIL INTO THU WEST PART AND INTO THU NIGHT EAST PART.
THERE WILL BE A BRIEF LULL IN WINDS AND WAVES FOR THE WEST PART OF
THE LAKE LATER TONIGHT INTO THE BEGINNING OF TUE BUT CONSENSUS IS TO
JUST LEAVE THE SCA GOING SINCE CONDITIONS RAMP BACK UP QUICKLY LATER
TUE MORNING.
THE GRADIENT WILL REMAIN RATHER STRONG WEDNESDAY INTO
THURSDAY...THEN RELAX AS THE SURFACE HIGH MOVES EAST ACROSS THE OHIO
VALLEY. A STORM SYSTEM WILL AFFECT THE LOWER GREAT LAKES ON THE
WEEKEND BUT NOT MUCH CONFIDENCE ON THE STRENGTH AND TRACK OF THE
SYSTEM YET.
&&
.CLE WATCHES/WARNINGS/ADVISORIES...
OH...NONE.
PA...NONE.
MARINE...SMALL CRAFT ADVISORY UNTIL 10 PM EST THURSDAY FOR LEZ145>149.
SMALL CRAFT ADVISORY UNTIL 10 AM EST THURSDAY FOR LEZ142>144.
&&
$$
SYNOPSIS...MAYERS
NEAR TERM...KIELTYKA
SHORT TERM...KIELTYKA/MAYERS
LONG TERM...KOSARIK
AVIATION...ADAMS
MARINE...ADAMS/KOSARIK
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
844 AM EST TUE DEC 10 2013
.SYNOPSIS...
SNOW WILL MOVE QUICKLY TO THE EAST THIS MORNING. A VERY COLD AND
BRISK WEST TO NORTHWEST FLOW WILL DEVELOP IN THE WAKE OF THIS
SYSTEM...AND BRING MUCH COLDER AIR WITH BELOW NORMAL TEMPERATURES
GRIPPING THE REGION THROUGH MID TO LATE WEEK. MODERATE TO LOCALLY
HEAVY LAKE EFFECT SNOWS ARE ALSO FORECAST IN PERENNIAL SNOWBELT
ACROSS THE NORTHWEST MOUNTAINS INTO THE SECOND HALF OF THE WEEK.
ELSEWHERE...IT WILL BE GENERALLY COLD AND DRY. THE ACTIVE EARLY
SEASON WINTER PATTERN LOOKS TO RESUME WITH ANOTHER STORM SYSTEM
LIKELY AFFECTING THE AREA OVER THE WEEKEND.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
830 AM UPDATE...
IT TOOK A WHILE TO MOISTEN THE LOWER ATMOS THIS MORNING. SNOW
JUST NOT FALLING IN THE WRN HALF OF THE ADVY AREA. THE AREA OF
LIGHT SNOW IN WRN PA IS DIMINISHING QUICKLY AND SHOULD BE GONE BY
10 AM. HAVE CANCELLED THE ADVY FOR LOCATIONS WEST OF FRANKLIN
COUNTY. EVEN AREAS TO THE NORTH OF HARRISBURG ARE EASILY IN
JEOPARDY OF NOT RECEIVING MORE THAN AN INCH OR TWO OF SNOW TOTAL.
HAVE ADJUSTED POPS/TIMING/AMNTS ACCORDINGLY.
PREV...
DESPITE A LACK OF -SN BEING REPORTED IN THE SFC OBS...A QUICK
GLANCE AT AREA WEBCAMS SHOWS SNOW IS REACHING THE GROUND IN SRN
PA.
EMBEDDED WITHIN THE BASE OF A PROGRESSIVE 500MB TROUGH...FAST-
MOVG SHORTWAVE ENERGY AND STG HEIGHT FALLS /APPROACHING -200M IN
12HR/ WILL RACE EWD ACROSS THE UPPER OH VLY EARLY THIS MORNING AND
MOVE THROUGH CENTRAL PA BTWN 15-21Z. DOWNSTREAM WARM AIR/MSTR
ADVECTION INTERACTING WITH STRONG DIVERGENCE ALOFT ALONG THE
RIGHT-ENTRANCE REGION OF A POWERFUL 175KT UPPER JET STREAK WILL
CONTINUE TO ALLOW FOR A RAPID NEWD EXPANSION OF LGT-MOD SNOW
QUICKLY SPREADING ACROSS SOUTH-CENTRAL AND SERN PA EARLY THIS
MORNING.
A CONSENSUS OF SHORT-RANGE HIRES MODELS SHOWS THE PERIOD OF MOST
INTENSE SNOWS OCCURRING FROM MID-LATE MORNING BEFORE SNOW QUICKLY
TAPERS OFF FROM W-E BY MID TO LATE AFTN. THE RAPID PROGRESSION OF
THIS SYSTEM SHOULD LIMIT WIDESPREAD HEAVY AMTS WITH SNFL TOTALS
GENERALLY IN THE 1-3/2-4" RANGE. HOWEVER...LOCALLY HEAVIER AMTS
ARE POSSIBLE ESPECIALLY ALONG/S OF I-81 WHERE ENHANCED LOW-MID LVL
FGEN AND MESO BANDING MAY SUPPORT A NARROW SWATH OF 4-6". THE
LATEST RUC ALONG WITH THE HIRES WRF/NMM SUGGEST THE GREATEST
POTENTIAL FOR HEAVY SNOW BANDING AND SNFL RATES BTWN 0.5-1" PER
HOUR IS ALONG/S OF RT 30...WHERE THE FINAL NDFD SNFL GRAPHICS
SHOW STORM TOTALS OF 3-5". THE ONLY CHANGE TO THE WW ADVY WAS TO
BREAKOUT THE LWR SUSQ COUNTIES TO HIGHLIGHT EXPECTED HIER AMTS.
THE MESO MODELS SHOW THE BULK OF THE ACCUM SNOW ENDING OVER THE
LAURELS AND CNTRL MTNS BY 18Z...AND A FEW HOURS LATER IN THE MID-
LWR SUSQ. INC WEST WINDS AND FALLING TEMPS WILL DROP WIND CHILLS
SINGLE DIGITS AND LOW TEENS ACRS THE WRN ALLEGHENIES BY DARK.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH FRIDAY NIGHT/...
IN THE WAKE OF THE FAST-MOVING WINTER SYSTEM...A VIGOROUS CYCLONIC/NW
FLOW PATTERN WILL GRIP THE REGION WITH BELOW NORMAL TEMPS AND LAKE
EFFECT SNOWS THROUGH THE END OF THE WEEK. A REINFORCING SHOT OF
COLD AIR FOLLOWING THE PASSAGE OF A NRN CLIPPER ON WED WILL HELP
SUPPORT PERSISTENT...MAINLY W-E ORIENTED LES BANDS OVER THE
PERENNIAL NW SNOWBELT IN NRN WARREN/MCKEAN COS WITH ACCUMS IN
EXCESS OF 6" POSSIBLE BY THE END OF THE PD.
OTHER THAN THE LES SNOW IN THE NW MTNS...MUCH OF THE REMAINDER OF
THE AREA WILL BE COLD AND DRY. A CONSENSUS OF ALL MAX TEMP
GUIDANCE SHOWS DAYTIME DEPARTURES OF -20F ACROSS MUCH OF THE AREA
THU. WIND CHILLS WILL BE VERY COLD ESPECIALLY AT NIGHT AND IN THE
EARLY MORNING WITH VALUES IN THE SINGLE DIGITS EITHER SIDE OF ZERO.
HIGHLIGHTED THE WIND CHILLS IN THE HWO.
THE GFS/ECMWF EVENTUALLY SHOW THE LAKE EFFECT WINDING DOWN AS HIGH
PRESSURE ARRIVES IN THE MID-ATLC ON FRIDAY.
&&
.LONG TERM /SATURDAY THROUGH MONDAY/...
THE ACTIVE EARLY SEASON WINTER PATTERN LOOKS TO RESUME BY THE
WEEKEND...AS THE ENERGETIC SPLIT FLOW UPSTREAM MERGES OVER THE
CENTRAL STATES...ALLOWING LOW PRESSURE TO DEVELOP IN THE LWR MS
REGION AND TRACK NEWD INTO THE MID-ATLC/NORTHEAST STATES. WHILE
THERE IS REASONABLE CONVERGENCE OF SOLUTIONS ON A STORM
SYSTEM...THE DETAILS WILL NEED SORTING-OUT AT SHORTER RANGES TO
DETERMINE SENSIBLE WX IMPACTS SUCH AS TIMING AND PTYPES. AT FIRST
GLANCE...THE SET-UP IS SOMEWHAT SIMILAR TO THIS PAST SUNDAY`S
SYSTEM WITH MIXED PRECIP AGAIN A CONCERN. THE COLD AIR PRECEDING
THE NEW SYSTEM SHOULD BE MORE ROBUST WHICH SUGGESTS AN INCREASED
CHANCE FOR FROZEN/FREEZING PTYPES.
INCREASED POPS AROUND DAY 5 WITH REASONABLE MODEL AGREEMENT
HOWEVER CONFIDENCE IN TIMING IS BELOW AVG GIVEN DIFFS IN THE
OPRN GFS/EC AND THEIR RESPECTIVE ENSEMBLE MEANS.
&&
.AVIATION /14Z TUESDAY THROUGH SATURDAY/...
SNOW HAS BEGUN TO FALL ACROSS SOUTHEASTERN PA...WITH LIFR
CONDITIONS AT MDT AND LNS. THESE CIGS AND VSBYS SHOULD CONTINUE
THROUGH THE MORNING...TAPERING OFF BETWEEN 16 TO 18Z. THIS IS DUE
TO A FAST-MOVING LOW PRESSURE SYSTEM THAT WILL SPREAD A PERIOD OF
SNOW ACROSS MAINLY SOUTHERN PA UNTIL 18Z. LIGHTER SNOW WILL FALL
FURTHER NORTH...WITH ONE TO THREE ACCUMULATIONS POSSIBLE. MVFR
CIGS AND VSBYS REMAIN POSSIBLE THROUGHOUT THE REST OF THE TAF
SITES THROUGH THIS TIMEFRAME.
AFTER 18Z EXPECT CONDITIONS TO IMPROVE...WITH VFR DOMINATING
CONDITIONS AFTER 22Z. THE ONLY CAVEAT WILL BE BFD WHERE THERE
SHOULD BE A DROP IN CIGS AND VSBYS TO MVFR/IFR OVERNIGHT TONIGHT
DUE TO NW FLOW AND LAKE ENHANCED SHOWERS.
OUTLOOK...
WED...PM SHSN/REDUCED VSBYS POSSIBLE W MTNS.
THU...SHSN/REDUCED VSBYS POSSIBLE NW MTNS.
FRI...NO SIG WX EXPECTED.
SAT...MIXED PRECIP WITH LOW CIGS/VSBYS POSSIBLE.
&&
.CTP WATCHES/WARNINGS/ADVISORIES...
WINTER WEATHER ADVISORY UNTIL 4 PM EST THIS AFTERNOON FOR
PAZ028-036-049>053-056>059-063>066.
&&
$$
SYNOPSIS...STEINBUGL
NEAR TERM...DANGELO/STEINBUGL
SHORT TERM...STEINBUGL
LONG TERM...STEINBUGL
AVIATION...FITZGERALD/CERU
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
724 AM EST TUE DEC 10 2013
.SYNOPSIS...
ANOTHER WINTER WEATHER SYSTEM WILL BRING LIGHT TO MODERATE
SNOWFALL TO PORTIONS OF CENTRAL AND SOUTHEASTERN PENNSYLVANIA
TODAY. A VERY COLD AND BRISK WEST TO NORTHWEST FLOW WILL DEVELOP
IN THE WAKE OF THIS SYSTEM...AND BRING MUCH COLDER AIR WITH BELOW
NORMAL TEMPERATURES GRIPPING THE REGION THROUGH MID-TO-LATE WEEK.
MODERATE TO LOCALLY HEAVY LAKE EFFECT SNOWS ARE ALSO FORECAST IN
PERENNIAL SNOWBELT ACROSS THE NORTHWEST MOUNTAINS INTO THE SECOND
HALF OF THE WEEK. ELSEWHERE...IT WILL BE GENERALLY COLD AND DRY.
THE ACTIVE EARLY SEASON WINTER PATTERN LOOKS TO RESUME WITH
ANOTHER STORM SYSTEM LIKELY AFFECTING THE AREA OVER THE WEEKEND.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
DESPITE A LACK OF -SN BEING REPORTED IN THE SFC OBS...A QUICK
GLANCE AT AREA WEBCAMS SHOWS SNOW IS REACHING THE GROUND IN SRN
PA.
EMBEDDED WITHIN THE BASE OF A PROGRESSIVE 500MB TROUGH...FAST-
MOVG SHORTWAVE ENERGY AND STG HEIGHT FALLS /APPROACHING -200M IN
12HR/ WILL RACE EWD ACROSS THE UPPER OH VLY EARLY THIS MORNING AND
MOVE THROUGH CENTRAL PA BTWN 15-21Z. DOWNSTREAM WARM AIR/MSTR
ADVECTION INTERACTING WITH STRONG DIVERGENCE ALOFT ALONG THE
RIGHT-ENTRANCE REGION OF A POWERFUL 175KT UPPER JET STREAK WILL
CONTINUE TO ALLOW FOR A RAPID NEWD EXPANSION OF LGT-MOD SNOW
QUICKLY SPREADING ACROSS SOUTH-CENTRAL AND SERN PA EARLY THIS
MORNING.
A CONSENSUS OF SHORT-RANGE HIRES MODELS SHOWS THE PERIOD OF MOST
INTENSE SNOWS OCCURRING FROM MID-LATE MORNING BEFORE SNOW QUICKLY
TAPERS OFF FROM W-E BY MID TO LATE AFTN. THE RAPID PROGRESSION OF
THIS SYSTEM SHOULD LIMIT WIDESPREAD HEAVY AMTS WITH SNFL TOTALS
GENERALLY IN THE 1-3/2-4" RANGE. HOWEVER...LOCALLY HEAVIER AMTS
ARE POSSIBLE ESPECIALLY ALONG/S OF I-81 WHERE ENHANCED LOW-MID LVL
FGEN AND MESO BANDING MAY SUPPORT A NARROW SWATH OF 4-6". THE
LATEST RUC ALONG WITH THE HIRES WRF/NMM SUGGEST THE GREATEST
POTENTIAL FOR HEAVY SNOW BANDING AND SNFL RATES BTWN 0.5-1" PER
HOUR IS ALONG/S OF RT 30...WHERE THE FINAL NDFD SNFL GRAPHICS
SHOW STORM TOTALS OF 3-5". THE ONLY CHANGE TO THE WW ADVY WAS TO
BREAKOUT THE LWR SUSQ COUNTIES TO HIGHLIGHT EXPECTED HIER AMTS.
THE MESO MODELS SHOW THE BULK OF THE ACCUM SNOW ENDING OVER THE
LAURELS AND CNTRL MTNS BY 18Z...AND A FEW HOURS LATER IN THE MID-
LWR SUSQ. INC WEST WINDS AND FALLING TEMPS WILL DROP WIND CHILLS
SINGLE DIGITS AND LOW TEENS ACRS THE WRN ALLEGHENIES BY DARK.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH FRIDAY NIGHT/...
IN THE WAKE OF THE FAST-MOVING WINTER SYSTEM...A VIGOROUS CYCLONIC/NW
FLOW PATTERN WILL GRIP THE REGION WITH BELOW NORMAL TEMPS AND LAKE
EFFECT SNOWS THROUGH THE END OF THE WEEK. A REINFORCING SHOT OF
COLD AIR FOLLOWING THE PASSAGE OF A NRN CLIPPER ON WED WILL HELP
SUPPORT PERSISTENT...MAINLY W-E ORIENTED LES BANDS OVER THE
PERENNIAL NW SNOWBELT IN NRN WARREN/MCKEAN COS WITH ACCUMS IN
EXCESS OF 6" POSSIBLE BY THE END OF THE PD.
OTHER THAN THE LES SNOW IN THE NW MTNS...MUCH OF THE REMAINDER OF
THE AREA WILL BE COLD AND DRY. A CONSENSUS OF ALL MAX TEMP
GUIDANCE SHOWS DAYTIME DEPARTURES OF -20F ACROSS MUCH OF THE AREA
THU. WIND CHILLS WILL BE VERY COLD ESPECIALLY AT NIGHT AND IN THE
EARLY MORNING WITH VALUES IN THE SINGLE DIGITS EITHER SIDE OF ZERO.
HIGHLIGHTED THE WIND CHILLS IN THE HWO.
THE GFS/ECMWF EVENTUALLY SHOW THE LAKE EFFECT WINDING DOWN AS HIGH
PRESSURE ARRIVES IN THE MID-ATLC ON FRIDAY.
&&
.LONG TERM /SATURDAY THROUGH MONDAY/...
THE ACTIVE EARLY SEASON WINTER PATTERN LOOKS TO RESUME BY THE
WEEKEND...AS THE ENERGETIC SPLIT FLOW UPSTREAM MERGES OVER THE
CENTRAL STATES...ALLOWING LOW PRESSURE TO DEVELOP IN THE LWR MS
REGION AND TRACK NEWD INTO THE MID-ATLC/NORTHEAST STATES. WHILE
THERE IS REASONABLE CONVERGENCE OF SOLUTIONS ON A STORM
SYSTEM...THE DETAILS WILL NEED SORTING-OUT AT SHORTER RANGES TO
DETERMINE SENSIBLE WX IMPACTS SUCH AS TIMING AND PTYPES. AT FIRST
GLANCE...THE SET-UP IS SOMEWHAT SIMILAR TO THIS PAST SUNDAY`S
SYSTEM WITH MIXED PRECIP AGAIN A CONCERN. THE COLD AIR PRECEDING
THE NEW SYSTEM SHOULD BE MORE ROBUST WHICH SUGGESTS AN INCREASED
CHANCE FOR FROZEN/FREEZING PTYPES.
INCREASED POPS AROUND DAY 5 WITH REASONABLE MODEL AGREEMENT
HOWEVER CONFIDENCE IN TIMING IS BELOW AVG GIVEN DIFFS IN THE
OPRN GFS/EC AND THEIR RESPECTIVE ENSEMBLE MEANS.
&&
.AVIATION /12Z TUESDAY THROUGH SATURDAY/...
SNOW HAS BEGUN TO FALL ACROSS SOUTHEASTERN PA...WITH LIFR
CONDITIONS AT MDT AND LNS. THESE CIGS AND VSBYS SHOULD CONTINUE
THROUGH THE MORNING...TAPERING OFF BETWEEN 16 TO 18Z. THIS IS DUE
TO A FAST-MOVING LOW PRESSURE SYSTEM THAT WILL SPREAD A PERIOD OF
SNOW ACROSS MAINLY SOUTHERN PA UNTIL 18Z. LIGHTER SNOW WILL FALL
FURTHER NORTH...WITH ONE TO THREE ACCUMULATIONS POSSIBLE. MVFR
CIGS AND VSBYS REMAIN POSSIBLE THROUGHOUT THE REST OF THE TAF
SITES THROUGH THIS TIMEFRAME.
AFTER 18Z EXPECT CONDITIONS TO IMPROVE...WITH VFR DOMINATING
CONDITIONS AFTER 22Z. THE ONLY CAVEAT WILL BE BFD WHERE THERE
SHOULD BE A DROP IN CIGS AND VSBYS TO MVFR/IFR OVERNIGHT TONIGHT
DUE TO NW FLOW AND LAKE ENHANCED SHOWERS.
OUTLOOK...
WED...PM SHSN/REDUCED VSBYS POSSIBLE W MTNS.
THU...SHSN/REDUCED VSBYS POSSIBLE NW MTNS.
FRI...NO SIG WX EXPECTED.
SAT...MIXED PRECIP WITH LOW CIGS/VSBYS POSSIBLE.
&&
.CTP WATCHES/WARNINGS/ADVISORIES...
WINTER WEATHER ADVISORY UNTIL 4 PM EST THIS AFTERNOON FOR
PAZ024>028-033>036-049>053-056>059-063>066.
&&
$$
SYNOPSIS...STEINBUGL
NEAR TERM...STEINBUGL
SHORT TERM...STEINBUGL
LONG TERM...STEINBUGL
AVIATION...FITZGERALD/CERU
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
551 AM EST TUE DEC 10 2013
.SYNOPSIS...
ANOTHER WINTER WEATHER SYSTEM WILL BRING LIGHT TO MODERATE
SNOWFALL TO PORTIONS OF CENTRAL AND SOUTHEASTERN PENNSYLVANIA
TODAY. A VERY COLD AND BRISK WEST TO NORTHWEST FLOW WILL DEVELOP
IN THE WAKE OF THIS SYSTEM...AND BRING MUCH COLDER AIR WITH BELOW
NORMAL TEMPERATURES GRIPPING THE REGION THROUGH MID-TO-LATE WEEK.
MODERATE TO LOCALLY HEAVY LAKE EFFECT SNOWS ARE ALSO FORECAST IN
PERENNIAL SNOWBELT ACROSS THE NORTHWEST MOUNTAINS INTO THE SECOND
HALF OF THE WEEK. ELSEWHERE...IT WILL BE GENERALLY COLD AND DRY.
THE ACTIVE EARLY SEASON WINTER PATTERN LOOKS TO RESUME WITH
ANOTHER STORM SYSTEM LIKELY AFFECTING THE AREA OVER THE WEEKEND.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
DESPITE A LACK OF -SN BEING REPORTED IN THE SFC OBS...A QUICK
GLANCE AT AREA WEBCAMS SHOWS SNOW IS REACHING THE GROUND IN SRN
PA.
EMBEDDED WITHIN THE BASE OF A PROGRESSIVE 500MB TROUGH...FAST-
MOVG SHORTWAVE ENERGY AND STG HEIGHT FALLS /APPROACHING -200M IN
12HR/ WILL RACE EWD ACROSS THE UPPER OH VLY EARLY THIS MORNING AND
MOVE THROUGH CENTRAL PA BTWN 15-21Z. DOWNSTREAM WARM AIR/MSTR
ADVECTION INTERACTING WITH STRONG DIVERGENCE ALOFT ALONG THE
RIGHT-ENTRANCE REGION OF A POWERFUL 175KT UPPER JET STREAK WILL
CONTINUE TO ALLOW FOR A RAPID NEWD EXPANSION OF LGT-MOD SNOW
QUICKLY SPREADING ACROSS SOUTH-CENTRAL AND SERN PA EARLY THIS
MORNING.
A CONSENSUS OF SHORT-RANGE HIRES MODELS SHOWS THE PERIOD OF MOST
INTENSE SNOWS OCCURRING FROM MID-LATE MORNING BEFORE SNOW QUICKLY
TAPERS OFF FROM W-E BY MID TO LATE AFTN. THE RAPID PROGRESSION OF
THIS SYSTEM SHOULD LIMIT WIDESPREAD HEAVY AMTS WITH SNFL TOTALS
GENERALLY IN THE 1-3/2-4" RANGE. HOWEVER...LOCALLY HEAVIER AMTS
ARE POSSIBLE ESPECIALLY ALONG/S OF I-81 WHERE ENHANCED LOW-MID LVL
FGEN AND MESO BANDING MAY SUPPORT A NARROW SWATH OF 4-6". THE
LATEST RUC ALONG WITH THE HIRES WRF/NMM SUGGEST THE GREATEST
POTENTIAL FOR HEAVY SNOW BANDING AND SNFL RATES BTWN 0.5-1" PER
HOUR IS ALONG/S OF RT 30...WHERE THE FINAL NDFD SNFL GRAPHICS
SHOW STORM TOTALS OF 3-5". THE ONLY CHANGE TO THE WW ADVY WAS TO
BREAKOUT THE LWR SUSQ COUNTIES TO HIGHLIGHT EXPECTED HIER AMTS.
THE MESO MODELS SHOW THE BULK OF THE ACCUM SNOW ENDING OVER THE
LAURELS AND CNTRL MTNS BY 18Z...AND A FEW HOURS LATER IN THE MID-
LWR SUSQ. INC WEST WINDS AND FALLING TEMPS WILL DROP WIND CHILLS
SINGLE DIGITS AND LOW TEENS ACRS THE WRN ALLEGHENIES BY DARK.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH FRIDAY NIGHT/...
IN THE WAKE OF THE FAST-MOVING WINTER SYSTEM...A VIGOROUS CYCLONIC/NW
FLOW PATTERN WILL GRIP THE REGION WITH BELOW NORMAL TEMPS AND LAKE
EFFECT SNOWS THROUGH THE END OF THE WEEK. A REINFORCING SHOT OF
COLD AIR FOLLOWING THE PASSAGE OF A NRN CLIPPER ON WED WILL HELP
SUPPORT PERSISTENT...MAINLY W-E ORIENTED LES BANDS OVER THE
PERENNIAL NW SNOWBELT IN NRN WARREN/MCKEAN COS WITH ACCUMS IN
EXCESS OF 6" POSSIBLE BY THE END OF THE PD.
OTHER THAN THE LES SNOW IN THE NW MTNS...MUCH OF THE REMAINDER OF
THE AREA WILL BE COLD AND DRY. A CONSENSUS OF ALL MAX TEMP
GUIDANCE SHOWS DAYTIME DEPARTURES OF -20F ACROSS MUCH OF THE AREA
THU. WIND CHILLS WILL BE VERY COLD ESPECIALLY AT NIGHT AND IN THE
EARLY MORNING WITH VALUES IN THE SINGLE DIGITS EITHER SIDE OF ZERO.
HIGHLIGHTED THE WIND CHILLS IN THE HWO.
THE GFS/ECMWF EVENTUALLY SHOW THE LAKE EFFECT WINDING DOWN AS HIGH
PRESSURE ARRIVES IN THE MID-ATLC ON FRIDAY.
&&
.LONG TERM /SATURDAY THROUGH MONDAY/...
THE ACTIVE EARLY SEASON WINTER PATTERN LOOKS TO RESUME BY THE
WEEKEND...AS THE ENERGETIC SPLIT FLOW UPSTREAM MERGES OVER THE
CENTRAL STATES...ALLOWING LOW PRESSURE TO DEVELOP IN THE LWR MS
REGION AND TRACK NEWD INTO THE MID-ATLC/NORTHEAST STATES. WHILE
THERE IS REASONABLE CONVERGENCE OF SOLUTIONS ON A STORM
SYSTEM...THE DETAILS WILL NEED SORTING-OUT AT SHORTER RANGES TO
DETERMINE SENSIBLE WX IMPACTS SUCH AS TIMING AND PTYPES. AT FIRST
GLANCE...THE SET-UP IS SOMEWHAT SIMILAR TO THIS PAST SUNDAY`S
SYSTEM WITH MIXED PRECIP AGAIN A CONCERN. THE COLD AIR PRECEDING
THE NEW SYSTEM SHOULD BE MORE ROBUST WHICH SUGGESTS AN INCREASED
CHANCE FOR FROZEN/FREEZING PTYPES.
INCREASED POPS AROUND DAY 5 WITH REASONABLE MODEL AGREEMENT
HOWEVER CONFIDENCE IN TIMING IS BELOW AVG GIVEN DIFFS IN THE
OPRN GFS/EC AND THEIR RESPECTIVE ENSEMBLE MEANS.
&&
.AVIATION /10Z TUESDAY THROUGH SATURDAY/...
LOW CIGS/FOG PERSISTING LATE THIS EVENING ACROSS SOUTHEAST PA
BENEATH TEMPERATURE INVERSION WITH LGT WINDS. LATEST MDL DATA
SUGGESTS INVERSION AND ASSOC LOW CIGS/FOG MAY FINALLY BE SCOURED
OUT BETWEEN 06Z AND 07Z AT KMDT. HOWEVER...OUTLOOK NOT AS FAVORABLE
ANY FURTHER SE...WITH KLNS LIKELY REMAINING SOCKED IN THROUGH 09Z.
ELSEWHERE...RESIDUAL LOW LVL MOISTURE FORCED TO ASCEND THE ALLEGHENY
MTNS HAS ALLOWED STRATOCU ACROSS THE W MTNS WITH MVFR CIGS AT
JST/KBFD/KAOO/KUNV. SEE LITTLE CHANGE IS THESE CONDS FOR MUCH OF THE
NIGHT...ALTHOUGH DOWNSLOPING FLOW EAST OF THE MTNS SHOULD
MAINTAIN VFR CONDS AT KIPT.
A FAST-MOVING LOW PRESSURE SYSTEM WILL TRACK SOUTH OF PA TUESDAY
MORNING...SPREADING A PERIOD OF SNOW ACROSS MAINLY SOUTHERN PA
BTWN 10Z-18Z. IFR VSBYS APPEAR LIKELY DURING LATE AM/EARLY AFTN AT
KMDT AND KLNS. LIGHTER SNOW WILL FALL FURTHER NORTH. HOWEVER...A
BRIEF DIP TO IFR VSBYS IS POSSIBLE ELSEWHERE TUE AM. IMPROVING
CONDS ARE EXPECTED BY TUE AFTN AS THE LOW PRES SYSTEM PASSES OFF
THE MID ATLANTIC COAST.
OUTLOOK...
WED...PM SHSN/REDUCED VSBYS POSSIBLE W MTNS.
THU...SHSN/REDUCED VSBYS POSSIBLE NW MTNS.
FRI...NO SIG WX EXPECTED.
SAT...MIXED PRECIP WITH LOW CIGS/VSBYS POSSIBLE.
&&
.CTP WATCHES/WARNINGS/ADVISORIES...
WINTER WEATHER ADVISORY UNTIL 4 PM EST THIS AFTERNOON FOR
PAZ024>028-033>036-049>053-056>059-063>066.
&&
$$
SYNOPSIS...STEINBUGL
NEAR TERM...STEINBUGL
SHORT TERM...STEINBUGL
LONG TERM...STEINBUGL
AVIATION...FITZGERALD/CERU
AREA FORECAST DISCUSSION
NWS MORRISTOWN TN
331 AM EST TUE DEC 10 2013
.SHORT TERM...(TODAY AND TONIGHT)...RAIN MOVING NE ACROSS THE REGION
AS EXPECTED THIS MORNING. HOWEVER...TEMPS REMAIN IN THE MID 30S TO
MID 40S...EXCEPT FOR PERHAPS LOWER 30S ACROSS OUR NRN MOST PLATEAU
COUNTIES. RUC MODEL SHOWS 850 MB TEMPS FALLING BELOW 0 DEGS CELSIUS
ACROSS THE WINTER WEATHER ADVISORY AREAS BY 09Z TO 12Z...SO STILL
SOME POTENTIAL FOR A BRIEF PERIOD OF ICING. ICE ACCUMS WERE LOWERED
IN FORECAST GRIDS DUE TO SURFACE TEMPS STILL ABOVE FREEZING FOR A
BIT LONGER. MODEL SOUNDINGS SHOW MAINLY LIGHT SNOW AS WEATHER TYPE
AFTER 12Z AS THE AIRMASS COOLS QUICKLY...SO DOWNPLAYED FREEZING RAIN
AND WENT WITH MAIN TYPE AS SNOW. ALL PCPN ENDS BY 16Z EVEN IN THE
FAR NE AREAS. NO CHANGES MADE TO THE ADVISORY AREA OR ENDING TIME.
OTHERWISE...STRONG COLD AIR ADVECTION FAVORS GOING WITH OR BELOW THE
COOLER MOS MAX TEMPS FOR TODAY. CLEAR AND CHILLY TONIGHT AS SURFACE
RIDGE OF HIGH PRESSURE SETTLES OVER THE REGION.
.LONG TERM.../WEDNESDAY THROUGH MONDAY/...
IN WAKE OF THE SHORTWAVE TROUGH THAT WILL MOVE THROUGH THE REGION ON
TUESDAY...ZONAL FLOW ALOFT WILL PREVAIL FOR THE REMAINDER OF THE
WORK WEEK AS A SURFACE HIGH PRESSURE BUILDS IN. THIS WILL RESULT IN
MOSTLY SUNNY AND DRY CONDITIONS...WITH HIGHS IN THE 40S TO LOWER
50S. BY FRIDAY HOWEVER...CLOUDS WILL GRADUALLY BE ON THE INCREASE AS
ANOTHER UPPER-LEVEL TROUGH SWINGS THROUGH THE SOUTHERN PLAINS AND
INTO THE LOWER MISSISSIPPI VALLEY. SOUTHERLY FLOW AHEAD OF THIS
SYSTEM WILL INCREASE GULF MOISTURE ACROSS THE AREA AND ALLOW FOR
PRECIPITATION TO OVERSPREAD THE REGION FRIDAY NIGHT INTO SATURDAY.
THEN AS THE BASE OF THE TROUGH SWINGS THROUGH THE TENNESSEE VALLEY
SATURDAY NIGHT INTO SUNDAY...COOLER AIR WILL FILTER INTO THE AREA
AND RESULT IN THE POTENTIAL FOR SOME WINTERY PRECIPITATION
/PARTICULARLY ALONG THE HIGHER TERRAIN OF THE CUMBERLAND PLATEAU...
SOUTHWEST VIRGINIA AND THE SMOKY MOUNTAINS OF EAST TENNESSEE/. ATTM
THERE IS A GREAT DEAL OF UNCERTAINTY WITH RESPECT TO THE POTENTIAL
IMPACT OF THE WINTER WEATHER GIVEN UNCERTAINTIES IN THE TIMING AND
TRACK OF THIS SYSTEM. THUS...HAVE BEEN CAUTIOUS IN ADJUSTING THE
FORECAST TOO MUCH ATTM...BUT HAVE INCREASED POPS TO SHOW A GREATER
CONFIDENCE IN PRECIPITATION OCCURRING DURING THIS TIME PERIOD. THE
PRECIPITATION WILL WANE ON SUNDAY...RESULTING IN DRY CONDITIONS TO
BEGIN THE NEW WORK WEEK ON MONDAY.
&&
.PRELIMINARY POINT TEMPS/POPS...
CHATTANOOGA AIRPORT, TN 44 25 50 26 43 / 20 10 0 0 0
KNOXVILLE MCGHEE TYSON AIRPORT, TN 42 23 46 25 38 / 50 10 0 0 0
OAK RIDGE, TN 41 23 45 24 39 / 40 10 0 0 0
TRI CITIES AIRPORT, TN 40 18 41 21 35 / 60 10 0 0 0
&&
.MRX WATCHES/WARNINGS/ADVISORIES...
NC...NONE.
TN...WINTER WEATHER ADVISORY UNTIL 11 AM EST /10 AM CST/ THIS MORNING
FOR THE FOLLOWING ZONES: ANDERSON...BLEDSOE...CAMPBELL...
CLAIBORNE...GRAINGER...HANCOCK...HAWKINS...JOHNSON...
MARION...MORGAN...SCOTT TN...SEQUATCHIE...SULLIVAN...UNION.
VA...WINTER WEATHER ADVISORY UNTIL 11 AM EST THIS MORNING FOR THE
FOLLOWING ZONES: LEE...RUSSELL...SCOTT...WASHINGTON...WISE.
&&
$$
TG/AMP
AREA FORECAST DISCUSSION
NWS NASHVILLE TN
1132 PM CST MON DEC 9 2013
.AVIATION 06Z DISCUSSION...
WINTRY PRECIPITATION TO OVERSPREAD THE MID STATE THROUGH 09Z. THE
PRECIP SHOULD END IN SOUTHWEST AREAS OF MIDDLE TN AROUND 10Z AND
THEN NORTHEAST AREAS AROUND 14Z. CONDITIONS WILL IMPROVE MARKEDLY
BY 18Z WITH CLEARING SKIES TOWARD 00Z.
THE BULK OF THE PRECIP TYPE WILL BE -SN AT BNA AND CKV.
CSV...HOWEVER...WILL CONTEND WITH -PL AND FZRA WITH A TRANSITION
TO SOME SNOW AROUND 09Z.
&&
.PREV DISCUSSION... /ISSUED 1044 PM CST MON DEC 9 2013/
UPDATE
RADAR INDICATING THAT THE PRECIPITATION APPROACHING BNA IS ALL
SNOW ABOVE 1200 FT. MELTING BELOW THAT LEVEL LOOKS UNLIKELY AND
THUS...SNOW SHOULD BEGIN SHORTLY ACROSS NORTHERN AREAS. MOSTLY
SLEET IS FALLING CENTRAL...AND FREEZING RAIN SOUTH. LAWRENCE AND
MARSHALL COUNTIES ARE BOTH REPORTING ICE COATING MOST ELEVATED
SURFACES.
CAA TO CONTINUE. THEREFORE...CURRENT FCST IS ON TRACK IN TERMS OF
TRANSITIONING. WE HAVE RECENTLY UPPED OUR SNOW
AMOUNTS...PARTICULARLY NC AND NE AREAS WHERE 1 TO 2 INCHED OF
SNOW IS NOW POSSIBLE. LESS THAN 1 INCH ACROSS THE NON ADVISORY NW
AREA.
FOR SOUTHERN AREAS...UP TO ONE QUARTER INCH OF ICE WILL BE
POSSIBLE.
ALL PRECIP SHOULD END SHORTLY AFTER SUNRISE ACROSS THE PLATEAU.
UPDATES HAVE BEEN SENT. STILL CONCERNED WITH LATEST RUC WHICH
PAINTS A LITTLE EXTRA QPF FROM NASHVILLE NE THROUGH THE EASTERN
HIGHLAND RIM AREA THROUGH 09Z. WILL AWAIT THE WHITES OF ITS EYES
BEFORE UPPING SNOW AMTS AGAIN. NOT SOLD ON RUC.
PREV DISCUSSION... /ISSUED 712 PM CST MON DEC 9 2013/
UPDATE...
SFC FREEZING LINE NOW EXTENDS GENERALLY ALONG I-65...WITH SUB
FREEZING TEMPS TO THE WEST EXCEPT 32-34 SOUTHWEST. TEMPS ACROSS
THE PLATEAU ARE IN THE LOW TO MID 30S. RADAR TRENDS FROM RADARS TO
OUR SOUTHWEST SHOW A DEFINITIVE INCREASE IN PRECIP COVERAGE ACROSS
MS AND EASTERN AR. MODELS ARE IN AGREEMENT WITH SPREADING THIS
MOISTURE NORTHEASTWARD RATHER RAPIDLY. BY 06Z...MUCH OF THE
SOUTHEASTERN TWO THIRDS OF THE MID STATE WILL BE RECEIVING
PRECIPITATION. IT STILL LOOKS AS THOUGH THE SOUTHERN AND PLATEAU
AREAS COULD RECEIVE TOTAL LIQ EQUIVALENT AMOUNTS OF BETWEEN ONE
QUARTER AND ONE HALF INCH. IF THE BULK OF THIS FALLS WITH SUB
FREEZING TEMPS IN PLACE...WE WILL NEED TO CONSIDER UPGRADING TO A
WINTER STORM WARNING FOR THAT EASTERN AND SOUTHERN AREA. FOR NOW
THOUGH...WILL KEEP THE ADVISORY GOING BUT WILL INCREASE ICE
AMOUNTS ACROSS THE SOUTH AND PLATEAU TO TWO TENTHS OF AN INCH.
WILL ALSO ADJUST GRAPHICS SO THAT SNOW AMOUNTS SUPPORT THE
ADVISORY CRITERIA ON THE NORTHWESTERN EDGE OF THE ADVISORY.
OTW...LATEST SOUNDING IS RATHER DRY ABOVE 800 MB AND LOOKS LIKE A
SNOW SOUNDING CONSIDERING THE UPCOMING WET BULB COOLING THAT WILL
TAKE PLACE. FURTHER SOUTH...FREEZING RAIN WILL BE THE BIGGER
IMPACT ACROSS THE SOUTH AND PLATEAU. AGAIN...THIS AREA WILL NEED
TO BE WATCHED. UPDATES OUT SHORTLY.
PREV DISCUSSION... /ISSUED 552 PM CST MON DEC 9 2013/
AVIATION 00Z DISCUSSION...
ANOTHER STORM SYSTEM WILL MOVE NORTHEASTWARD FROM THE NORTHERN
GULF AND SPREAD WINTRY PRECIPITATION BACK ACROSS THE MID STATE
OVERNIGHT. SOME SIGNIFICANT ICING WILL BE POSSIBLE NEAR CSV AFT
06Z. A GRADUAL SHIFT TO ALL SNOW CAN BE EXPECTED BETWEEN 9 AND
12Z. OVERALL PRECIP AMOUNTS WILL BE GREATEST ACROSS CSV WITH MUCH
LIGHTER AMOUNTS EXPECTED AT CKV.
THE IFR CIGS WILL CONTINUE THROUGH 18Z. AFT 18Z...PARTIAL CLEARING
IS EXPECTED.
PREV DISCUSSION... /ISSUED 420 PM CST MON DEC 9 2013/
SHORT TERM...
ANOTHER DAY ANOTHER ROUND OF WINTRY PRECIPITATION IS EXPECTED YET
AGAIN TONIGHT ACROSS THE MID STATE AS PRECIPITATION DEVELOPING TO
THE SOUTHWEST SPREADS NORTHEASTWARD ATOP THE COLD ARCTIC AIRMASS
ENTRENCHED OVER THE REGION. SHOWERS AND THUNDERSTORMS ARE NOW
DEVELOPING ACROSS TEXAS/LOUISIANA/MISSISSIPPI...AND THIS ACTIVITY
WILL SPREAD NORTHEASTWARD VERY RAPIDLY AND REACH THE MID STATE
THIS EVENING BEFORE SPREADING QUICKLY ACROSS THE AREA TONIGHT AND
EXITING BY TUESDAY MORNING. MODELS ARE FINALLY IN DECENT AGREEMENT
ON EVOLUTION OF SYSTEM TONIGHT...AND AFTER AN EXTENSIVE ANALYSIS
OF ALL 12Z MODEL DATA A WINTER WEATHER ADVISORY WAS ISSUED FOR THE
SOUTHEAST TWO-THIRDS OF THE MID STATE...ROUGHLY SOUTHEAST OF A
LINE FROM LINDEN TO GALLATIN.
AN EXTENSIVE LOOK AT 12Z GFS/NAM FORECAST SOUNDINGS INDICATE AREAS
ALONG AND SOUTH OF A LINE FROM WAYNESBORO TO CROSSVILLE WILL
INITIALLY SEE PRECIP FALL AS RAIN WITH TEMPERATURES IN THE MID
30S...BUT AS TEMPERATURES FALL BELOW FREEZING LATER THIS EVENING
AND TONIGHT A TRANSITION TO ALL FREEZING RAIN IS ANTICIPATED. QPF
AMOUNTS SUGGEST AROUND ONE TENTH OF ICE ACCUMULATION IS MOST
LIKELY IN THIS AREA...WITH MAIN IMPACTS BEING POTENTIALLY ICY
BRIDGES AND OVERPASSES. PRECIP MAY CHANGEOVER TO ALL SNOW TOWARDS
THE END OF THE EVENT BUT LITTLE OR NO SNOW ACCUMULATION IS LIKELY
IN THIS AREA.
NORTH OF THE LINE FROM WAYNESBORO TO CROSSVILLE IN THE ADVISORY
AREA...A MIX OF PRECIP TYPES IS EXPECTED INITIALLY WITH SOUNDINGS
DEPICTING A DEEP SURFACE COLD LAYER WITH ONLY A RELATIVELY WEAK
WARM NOSE ALOFT...SUGGESTING PREDOMINATELY SLEET OR SNOW FURTHER
NORTH AND FZRA FURTHER SOUTH. STRONG LIFT AND SATURATING/COOLING
OF THE ENTIRE COLUMN SHOULD CHANGE ANY SLEET/FZRA OVER TO SNOW
NEAR/AFTER MIDNIGHT IN THIS PART OF THE ADVISORY AREA. QPF
AMOUNTS INDICATE A DUSTING TO 1 INCH OF SNOW WOULD BE MOST COMMON
WITH HIGHEST AMOUNTS EAST OF I-65 AND NORTH OF I-40...WITH TRAVEL
SEEING THE MOST IMPACTS DUE TO POTENTIALLY SNOWY BRIDGES AND
OVERPASSES. LONGER DURATION OF PRECIP AND COOLER TEMP PROFILES
SUGGEST NORTHERN CUMBERLAND PLATEAU COULD END UP WITH HIGHER SNOW
ACCUMS...AND THIS WILL HAVE TO BE CLOSELY MONITORED AS THE EVENT
UNFOLDS.
PRECIPITATION WILL BE ENCOUNTERING A VERY DRY AIRMASS ALOFT TO THE
NORTHWEST OF THE MID STATE...AND A SHARP NORTHWEST EDGE TO THE PRECIP
SHIELD IS ANTICIPATED LIKELY SOMEWHERE ALONG A LINE FROM LINDEN TO
LAFAYETTE...WITH LITTLE OR NO PRECIP AT ALL ANTICIPATED IN
NORTHWEST ZONES. THIS BACK EDGE TO THE PRECIP GIVES THE FORECAST
CONSIDERABLE BUST POTENTIAL FOR THE NORTHWEST COUNTIES WITHIN THE
ADVISORY AREA. UNFORTUNATELY...THIS BACK EDGE TO THE PRECIP WILL
ALSO LIKELY BISECT THE NASHVILLE METRO...SO NORTHWEST PORTIONS OF
THE METRO AREA MAY SEE LITTLE OR NO PRECIPITATION WHILE SOUTHEAST
SECTIONS ARE MORE IMPACTED. EVEN MORE UNCERTAIN ARE CONVECTIVE
ELEMENTS WITH THE PRECIP AS SOUNDINGS DEPICT SOME ELEVATED
INSTABILITY...SO IF STRONGER CONVECTION CAN FORM FZRA/ICE/SNOW
AMOUNTS COULD BE HIGHER IN SOME LOCATIONS.
LONG TERM...
MAIN FORECAST FOCUS WAS ON WINTER WEATHER TONIGHT...SO FORECAST
FOR REST OF THE WEEK RELIED HEAVILY ON THE 12Z GFS. APPEARS CLOUDS
WILL FINALLY CLEAR ACROSS THE CWA BY TUESDAY AFTERNOON AS STRONG
NORTHWEST FLOW DEVELOPS IN THE LOW LEVELS...BUT THIS WILL RESULT
IN SEVERAL COLD DAYS FOR THE MIDDLE OF THE WEEK WITH LOWS IN THE
TEENS NORTHWEST TO 20 ELSEWHERE AND HIGHS ONLY IN THE 30S AND 40S.
WARMING TREND ANTICIPATED BY FRIDAY AS SURFACE RIDGE MOVES EAST
AND SOUTHERLY FLOW DEVELOPS. COULD SEE A BIT OF A RAIN/SNOW MIX ON
THE PLATEAU EARLY FRIDAY NIGHT...BUT EVENTUALLY ALL RAIN IS
EXPECTED EVERYWHERE AS TEMPS WARM CONSIDERABLY INTO SATURDAY.
STRONG CAA IN THE WAKE OF THE UPCOMING WEEKEND SYSTEM WILL BRING
MUCH COLDER TEMPERATURES AND OUR NEXT CHANCE FOR LIGHT SNOW
SATURDAY NIGHT...ALTHOUGH MAIN DEFORMATION BAND LOOKS TO STAY WELL
NORTH OF THE MID STATE.
&&
.OHX WATCHES/WARNINGS/ADVISORIES...
WINTER WEATHER ADVISORY UNTIL 9 AM CST TUESDAY FOR TNZ008>011-
027>034-056>066-075-077>080-093>095.
&&
$$
21
AREA FORECAST DISCUSSION
NWS NASHVILLE TN
1044 PM CST MON DEC 9 2013
.UPDATE
RADAR INDICATING THAT THE PRECIPITATION APPROACHING BNA IS ALL
SNOW ABOVE 1200 FT. MELTING BELOW THAT LEVEL LOOKS UNLIKELY AND
THUS...SNOW SHOULD BEGIN SHORTLY ACROSS NORTHERN AREAS. MOSTLY
SLEET IS FALLING CENTRAL...AND FREEZING RAIN SOUTH. LAWRENCE AND
MARSHALL COUNTIES ARE BOTH REPORTING ICE COATING MOST ELEVATED
SURFACES.
CAA TO CONTINUE. THEREFORE...CURRENT FCST IS ON TRACK IN TERMS OF
TRANSITIONING. WE HAVE RECENTLY UPPED OUR SNOW
AMOUNTS...PARTICULARLY NC AND NE AREAS WHERE 1 TO 2 INCHED OF
SNOW IS NOW POSSIBLE. LESS THAN 1 INCH ACROSS THE NON ADVISORY NW
AREA.
FOR SOUTHERN AREAS...UP TO ONE QUARTER INCH OF ICE WILL BE
POSSIBLE.
ALL PRECIP SHOULD END SHORTLY AFTER SUNRISE ACROSS THE PLATEAU.
UPDATES HAVE BEEN SENT. STILL CONCERNED WITH LATEST RUC WHICH
PAINTS A LITTLE EXTRA QPF FROM NASHVILLE NE THROUGH THE EASTERN
HIGHLAND RIM AREA THROUGH 09Z. WILL AWAIT THE WHITES OF ITS EYES
BEFORE UPPING SNOW AMTS AGAIN. NOT SOLD ON RUC.
PREV DISCUSSION... /ISSUED 712 PM CST MON DEC 9 2013/
UPDATE...
SFC FREEZING LINE NOW EXTENDS GENERALLY ALONG I-65...WITH SUB
FREEZING TEMPS TO THE WEST EXCEPT 32-34 SOUTHWEST. TEMPS ACROSS
THE PLATEAU ARE IN THE LOW TO MID 30S. RADAR TRENDS FROM RADARS TO
OUR SOUTHWEST SHOW A DEFINITIVE INCREASE IN PRECIP COVERAGE ACROSS
MS AND EASTERN AR. MODELS ARE IN AGREEMENT WITH SPREADING THIS
MOISTURE NORTHEASTWARD RATHER RAPIDLY. BY 06Z...MUCH OF THE
SOUTHEASTERN TWO THIRDS OF THE MID STATE WILL BE RECEIVING
PRECIPITATION. IT STILL LOOKS AS THOUGH THE SOUTHERN AND PLATEAU
AREAS COULD RECEIVE TOTAL LIQ EQUIVALENT AMOUNTS OF BETWEEN ONE
QUARTER AND ONE HALF INCH. IF THE BULK OF THIS FALLS WITH SUB
FREEZING TEMPS IN PLACE...WE WILL NEED TO CONSIDER UPGRADING TO A
WINTER STORM WARNING FOR THAT EASTERN AND SOUTHERN AREA. FOR NOW
THOUGH...WILL KEEP THE ADVISORY GOING BUT WILL INCREASE ICE
AMOUNTS ACROSS THE SOUTH AND PLATEAU TO TWO TENTHS OF AN INCH.
WILL ALSO ADJUST GRAPHICS SO THAT SNOW AMOUNTS SUPPORT THE
ADVISORY CRITERIA ON THE NORTHWESTERN EDGE OF THE ADVISORY.
OTW...LATEST SOUNDING IS RATHER DRY ABOVE 800 MB AND LOOKS LIKE A
SNOW SOUNDING CONSIDERING THE UPCOMING WET BULB COOLING THAT WILL
TAKE PLACE. FURTHER SOUTH...FREEZING RAIN WILL BE THE BIGGER
IMPACT ACROSS THE SOUTH AND PLATEAU. AGAIN...THIS AREA WILL NEED
TO BE WATCHED. UPDATES OUT SHORTLY.
PREV DISCUSSION... /ISSUED 552 PM CST MON DEC 9 2013/
AVIATION 00Z DISCUSSION...
ANOTHER STORM SYSTEM WILL MOVE NORTHEASTWARD FROM THE NORTHERN
GULF AND SPREAD WINTRY PRECIPITATION BACK ACROSS THE MID STATE
OVERNIGHT. SOME SIGNIFICANT ICING WILL BE POSSIBLE NEAR CSV AFT
06Z. A GRADUAL SHIFT TO ALL SNOW CAN BE EXPECTED BETWEEN 9 AND
12Z. OVERALL PRECIP AMOUNTS WILL BE GREATEST ACROSS CSV WITH MUCH
LIGHTER AMOUNTS EXPECTED AT CKV.
THE IFR CIGS WILL CONTINUE THROUGH 18Z. AFT 18Z...PARTIAL CLEARING
IS EXPECTED.
PREV DISCUSSION... /ISSUED 420 PM CST MON DEC 9 2013/
SHORT TERM...
ANOTHER DAY ANOTHER ROUND OF WINTRY PRECIPITATION IS EXPECTED YET
AGAIN TONIGHT ACROSS THE MID STATE AS PRECIPITATION DEVELOPING TO
THE SOUTHWEST SPREADS NORTHEASTWARD ATOP THE COLD ARCTIC AIRMASS
ENTRENCHED OVER THE REGION. SHOWERS AND THUNDERSTORMS ARE NOW
DEVELOPING ACROSS TEXAS/LOUISIANA/MISSISSIPPI...AND THIS ACTIVITY
WILL SPREAD NORTHEASTWARD VERY RAPIDLY AND REACH THE MID STATE
THIS EVENING BEFORE SPREADING QUICKLY ACROSS THE AREA TONIGHT AND
EXITING BY TUESDAY MORNING. MODELS ARE FINALLY IN DECENT AGREEMENT
ON EVOLUTION OF SYSTEM TONIGHT...AND AFTER AN EXTENSIVE ANALYSIS
OF ALL 12Z MODEL DATA A WINTER WEATHER ADVISORY WAS ISSUED FOR THE
SOUTHEAST TWO-THIRDS OF THE MID STATE...ROUGHLY SOUTHEAST OF A
LINE FROM LINDEN TO GALLATIN.
AN EXTENSIVE LOOK AT 12Z GFS/NAM FORECAST SOUNDINGS INDICATE AREAS
ALONG AND SOUTH OF A LINE FROM WAYNESBORO TO CROSSVILLE WILL
INITIALLY SEE PRECIP FALL AS RAIN WITH TEMPERATURES IN THE MID
30S...BUT AS TEMPERATURES FALL BELOW FREEZING LATER THIS EVENING
AND TONIGHT A TRANSITION TO ALL FREEZING RAIN IS ANTICIPATED. QPF
AMOUNTS SUGGEST AROUND ONE TENTH OF ICE ACCUMULATION IS MOST
LIKELY IN THIS AREA...WITH MAIN IMPACTS BEING POTENTIALLY ICY
BRIDGES AND OVERPASSES. PRECIP MAY CHANGEOVER TO ALL SNOW TOWARDS
THE END OF THE EVENT BUT LITTLE OR NO SNOW ACCUMULATION IS LIKELY
IN THIS AREA.
NORTH OF THE LINE FROM WAYNESBORO TO CROSSVILLE IN THE ADVISORY
AREA...A MIX OF PRECIP TYPES IS EXPECTED INITIALLY WITH SOUNDINGS
DEPICTING A DEEP SURFACE COLD LAYER WITH ONLY A RELATIVELY WEAK
WARM NOSE ALOFT...SUGGESTING PREDOMINATELY SLEET OR SNOW FURTHER
NORTH AND FZRA FURTHER SOUTH. STRONG LIFT AND SATURATING/COOLING
OF THE ENTIRE COLUMN SHOULD CHANGE ANY SLEET/FZRA OVER TO SNOW
NEAR/AFTER MIDNIGHT IN THIS PART OF THE ADVISORY AREA. QPF
AMOUNTS INDICATE A DUSTING TO 1 INCH OF SNOW WOULD BE MOST COMMON
WITH HIGHEST AMOUNTS EAST OF I-65 AND NORTH OF I-40...WITH TRAVEL
SEEING THE MOST IMPACTS DUE TO POTENTIALLY SNOWY BRIDGES AND
OVERPASSES. LONGER DURATION OF PRECIP AND COOLER TEMP PROFILES
SUGGEST NORTHERN CUMBERLAND PLATEAU COULD END UP WITH HIGHER SNOW
ACCUMS...AND THIS WILL HAVE TO BE CLOSELY MONITORED AS THE EVENT
UNFOLDS.
PRECIPITATION WILL BE ENCOUNTERING A VERY DRY AIRMASS ALOFT TO THE
NORTHWEST OF THE MID STATE...AND A SHARP NORTHWEST EDGE TO THE PRECIP
SHIELD IS ANTICIPATED LIKELY SOMEWHERE ALONG A LINE FROM LINDEN TO
LAFAYETTE...WITH LITTLE OR NO PRECIP AT ALL ANTICIPATED IN
NORTHWEST ZONES. THIS BACK EDGE TO THE PRECIP GIVES THE FORECAST
CONSIDERABLE BUST POTENTIAL FOR THE NORTHWEST COUNTIES WITHIN THE
ADVISORY AREA. UNFORTUNATELY...THIS BACK EDGE TO THE PRECIP WILL
ALSO LIKELY BISECT THE NASHVILLE METRO...SO NORTHWEST PORTIONS OF
THE METRO AREA MAY SEE LITTLE OR NO PRECIPITATION WHILE SOUTHEAST
SECTIONS ARE MORE IMPACTED. EVEN MORE UNCERTAIN ARE CONVECTIVE
ELEMENTS WITH THE PRECIP AS SOUNDINGS DEPICT SOME ELEVATED
INSTABILITY...SO IF STRONGER CONVECTION CAN FORM FZRA/ICE/SNOW
AMOUNTS COULD BE HIGHER IN SOME LOCATIONS.
LONG TERM...
MAIN FORECAST FOCUS WAS ON WINTER WEATHER TONIGHT...SO FORECAST
FOR REST OF THE WEEK RELIED HEAVILY ON THE 12Z GFS. APPEARS CLOUDS
WILL FINALLY CLEAR ACROSS THE CWA BY TUESDAY AFTERNOON AS STRONG
NORTHWEST FLOW DEVELOPS IN THE LOW LEVELS...BUT THIS WILL RESULT
IN SEVERAL COLD DAYS FOR THE MIDDLE OF THE WEEK WITH LOWS IN THE
TEENS NORTHWEST TO 20 ELSEWHERE AND HIGHS ONLY IN THE 30S AND 40S.
WARMING TREND ANTICIPATED BY FRIDAY AS SURFACE RIDGE MOVES EAST
AND SOUTHERLY FLOW DEVELOPS. COULD SEE A BIT OF A RAIN/SNOW MIX ON
THE PLATEAU EARLY FRIDAY NIGHT...BUT EVENTUALLY ALL RAIN IS
EXPECTED EVERYWHERE AS TEMPS WARM CONSIDERABLY INTO SATURDAY.
STRONG CAA IN THE WAKE OF THE UPCOMING WEEKEND SYSTEM WILL BRING
MUCH COLDER TEMPERATURES AND OUR NEXT CHANCE FOR LIGHT SNOW
SATURDAY NIGHT...ALTHOUGH MAIN DEFORMATION BAND LOOKS TO STAY WELL
NORTH OF THE MID STATE.
&&
.OHX WATCHES/WARNINGS/ADVISORIES...
WINTER WEATHER ADVISORY UNTIL 9 AM CST TUESDAY FOR TNZ008>011-
027>034-056>066-075-077>080-093>095.
&&
$$
21
FORECAST DISCUSSION FOR ROUTINE AFTERNOON FORECAST ISSUANCE
.SHORT TERM...TONIGHT AND WEDNESDAY
ISSUED AT 246 PM CST TUE DEC 10 2013
LATEST RUC ANALYSIS AND SATELLITE/RADAR IMAGERY SHOW THE EARLIER
CLIPPER EXITING THE REGION OVER NORTHEAST LOWER MICHIGAN. PARTIAL
CLEARING HAS OCCURRED BEHIND THE SYSTEM ACROSS THE STATE...BUT LIKE
YESTERDAY...STRATO-CU KEEPS RE-DEVELOPING WITHIN THE ARCTIC AIRMASS
DUE TO STEEP LOW-LEVEL LAPSE RATES. LIGHT SNOW SHOWERS/FLURRIES ARE
NOT AS WIDESPREAD AS YESTERDAY...BUT ARE STILL SHOWING UP ON RADAR
MAINLY OVER CENTRAL AND SOUTHERN WISCONSIN. THESE LIGHT SNOW
SHOWERS/FLURRIES SHOULD AGAIN SUBSIDE AROUND SUNSET. THEN ATTENTION
TURNS TO THE VARIOUS SHORTWAVES/CLIPPERS UPSTREAM. ONE CLIPPER OVER
LAKE WINNIPEG IS ANTICIPATED TO SWING ACROSS LAKE SUPERIOR AND THE
UPPER PENINSULA TONIGHT. A MORE POTENT WAVE RESIDES OVER MONTANA
WHICH WILL ALSO MOVE ACROSS THE REGION LATE OVERNIGHT. AS A
RESULT...LIGHT SNOW POTENTIAL AND WIND CHILL HEADLINES ARE THE MAIN
FORECAST CONCERNS IN THE SHORT TERM.
TONIGHT...ANOTHER FAST MOVING CLIPPER SYSTEM WILL SLIDE QUICKLY
SOUTHEAST INTO THE WESTERN GREAT LAKES/NORTHERN MISSISSIPPI VALLEY.
AHEAD OF THE SHORTWAVE...A WEAK SURFACE CIRCULATION WILL MOVE ACROSS
IOWA AND INTO NORTHERN ILLINOIS. FORCING IS NOT NEARLY AS ROBUST AS
THE PAST CLIPPER...AND THE TRACK IS A COUPLE HUNDRED MILES FURTHER
SOUTH AS WELL. BUT SEEMS TO HAVE ENOUGH MOISTURE ON THE NORTHERN
PERIPHERY OF THE SYSTEM FOR LIGHT SNOW TO GRAZE CENTRAL AND
EAST-CENTRAL WISCONSIN COUNTIES. HAVE KEPT THE CHANCE OF SNOW IN
THE FORECAST...BUT DID DELAY THE ARRIVAL A COUPLE HOURS TO MATCH THE
LATEST TRENDS. AS THE CLIPPER PASSES BY TO THE SOUTH...SHOULD SEE A
SECONDARY SURGE OF ARCTIC AIR ARRIVE LATE TONIGHT. THEREFORE
ANTICIPATE WIND CHILL READINGS TO FALL OFF QUICKLY OVERNIGHT AS THIS
SURGE OF ARCTIC AIR SPREADS EAST. ALREADY WILL BE NEAR WIND CHILL
ADVISORY CRITERIA OVER N-C WISCONSIN FOR THE EVENING...SO WILL NOT
TAKE MUCH COLDER AIR FOR CRITERIA TO BE MET. WILL KEEP THE START
TIME AS PLANNED...THOUGH N-C WISCONSIN MAY SEE THE CRITERIA BREACHED
AN HOUR OR TWO BEFORE ISSUANCE TIME. LITTLE CHANGE TO LOW TEMPS.
WEDNESDAY...CLEARING SKIES WILL TAKE PLACE WEDNESDAY MORNING AS THE
CORE OF THE ARCTIC AIR MOVES INTO THE FORECAST AREA. DESPITE MOSTLY
CLEAR TO PARTLY CLOUDY CONDITIONS...TEMPS WILL STRUGGLE TO RISE
ABOVE 0 DEGREES OVER CENTRAL AND NORTH-CENTRAL WISCONSIN. WIND
CHILL READINGS MAY RISE ABOVE ADVISORY CRITERIA FOR A FEW HOURS
DURING THE AFTERNOON OVER NORTHEAST WISCONSIN...ONLY TO FALL BELOW
AGAIN BY THE START OF THE EVENING. WILL THEREFORE LET THE WIND
CHILL HEADLINES GO INTO THE NEXT PERIOD.
.LONG TERM...WEDNESDAY NIGHT THROUGH TUESDAY
ISSUED AT 246 PM CST TUE DEC 10 2013
CONTINUED COLD TEMPERATURES AND PERIODIC SNOW CHANCES...MOST
NOTABLY FRIDAY NIGHT INTO SATURDAY...WILL BE THE MAIN FCST
CONCERNS.
MOSTLY CLEAR SKIES WILL ALLOW TEMPS TO FALL WELL BLO ZERO WEDNESDAY
EVENING...BUT WAA AND INCREASING CLOUDS WILL PROBABLY RESULT IN
STEADY OR SLOWLY WARMING TEMPS BEFORE DAYBREAK. ENOUGH SATURATION
SHOULD OCCUR OVER OUR SW COUNTIES LATE TO ALLOW SOME LIGHT SNOW OR
FLURRIES TO DEVELOP. STEADY WEST WINDS AND VERY COLD TEMPS WILL
RESULT IN BITTER COLD WIND CHILLS...WHICH WILL LINGER INTO EARLY
THURSDAY. HAVE EXTENDED THE WIND CHILL ADVISORY UNTIL 15Z THU.
WILL EVENTUALLY NEED TO ADD THE LAKESHORE COUNTIES TO THE ADVISORY
FOR WEDS NGT...BUT THAT CAN BE DONE WITH SUBSEQUENT FCSTS.
A VERY STRONG BAROCLINIC ZONE WILL BE IN PLACE FROM THURSDAY INTO
FRIDAY. WITH WAA CONTINUING ON THURSDAY...AND THE RRQ OF AN UPPER
JET...FRONTOGENETIC FORCING AND WEAK SHORT-WAVE ENERGY AFFECTING
THE REGION THU NGT/FRI...ENOUGH FORCING SHOULD BE PRESENT TO
CONTINUE A CHANCE OF LIGHT SNOW/FLURRIES THROUGH THE PERIOD. A
MODEST MODERATION IN TEMPS WILL OCCUR LATE IN THE WORK WEEK...
BUT BACKED OFF A LITTLE ON THE PREVIOUS MAX TEMPS FOR FRIDAY.
ITS STARTING TO LOOK MORE INTERESTING LATE FRI NGT/SATURDAY
AS AN INVERTED SFC TROF MOVES THROUGH THE REGION. LOW-LEVEL
CONVERGENCE IS EXPECTED TO BE QUITE STG IN THE FOX VALLEY/LKSHR
AREAS...AND SYNOPTIC FORCING SHOULD BE PROVIDED BY H8 WAA/ISENT
LIFT AND SOME UPPER JET ENERGY. LAKE-ENHANCEMENT IS LIKELY...WITH
E-SE WINDS OFF LAKE MICHIGAN AND LK-H8 DELTA-T`S OF 14-18 C. WILL
RAISE POPS TO LIKELY OVER THE FOX VALLEY AND ESPECIALLY THE
LAKESHORE COUNTIES...AND MENTION THE POSSIBILITY OF 2-4 INCH
ACCUMS (WITH LOCAL HIGHER AMOUNTS ON THE LKSHR) IN THE HAZARDOUS
WEATHER OUTLOOK.
THE FCST IS UP IN THE AIR SATURDAY NIGHT/SUNDAY...AS SOME OF
THE MEDIUM RANGE MODELS (ESPECIALLY THE GFS) BRING AN UPPER LOW
FARTHER SOUTH (THROUGH WI) AND LINGER THE INVERTED SFC TROF OVER
THE WESTERN GREAT LAKES REGION. ALTHOUGH THE ECMWF WAS STILL
TAKING THE UPPER LOW THROUGH LAKE SUPERIOR...IT HAD SHOWN A
FARTHER SOUTH SOLN A COUPLE DAYS AGO...SO THIS BEARS WATCHING.
AT THE LEAST...IT APPEARS THAT COLD CYCLONIC NORTH FLOW WILL
BRING ANOTHER SHOT OF ARCTIC AIR INTO THE REGION BY SUDAY...AND
CAUSE LAKE-ENHANCED SNOW TO INCREASE OVER NC WI. AT WORST...
ACCUMULATING SNOW COULD CONTINUE ACROSS MUCH OF THE FORECAST
AREA SATURDAY NIGHT INTO SUNDAY MORNING. FOR NOW...HAVE JUST
INCREASED POPS OVER THE LAKE SUPERIOR SNOW BELT. THE ARCTIC
SURGE SHOULD BE BRIEF.
THE CHANCE OF LIGHT SNOW OR FLURRIES WILL CONTINUE EARLY NEXT
WEEK...AS SEVERAL S/W TROFS MOVE THROUGH THE WESTERN GREAT
LAKES...AND THE ARCTIC BAROCLINIC ZONE OSCILLATES OVER THE
REGION.
&&
.AVIATION...FOR 18Z TAF ISSUANCE
ISSUED AT 1123 AM CST TUE DEC 10 2013
FAST MOVING CLIPPER IS EXITING THE REGION LATE THIS MORNING. SKIES
HAVE PARTIALLY CLEARED BEHIND THE SYSTEM THOUGH SCT TO BKN MVFR CIGS
ARE TRYING TO RE-DEVELOP ACROSS THE STATE WITH DAYTIME HEATING. A
FEW SPOTTY FLURRIES OR LIGHT SNOW SHOWERS ARE NOT OUT OF THE
QUESTION EITHER. WEST WINDS WILL BECOME GUSTY ONCE AGAIN THIS
AFTERNOON...WHICH WILL CREATE BLOWING SNOW ESPECIALLY IN THE OPEN
FIELDS. WINDS PARTIALLY CALM TONIGHT AS ANOTHER FAST MOVING CLIPPER
PASSES SOUTH OF THE REGION. MID LEVEL CLOUDS WILL BE INCREASING
THIS EVENING...AND A SMALL CHANCE OF LIGHT SNOW WILL MOVE INTO
CENTRAL AND EAST-CENTRAL WISCONSIN AFTER MIDNIGHT. THE CLIPPER WILL
QUICKLY EXIT THE REGION EARLY WEDNESDAY MORNING...LEAVING MOSTLY
CLEAR AND VERY COLD CONDITIONS IN PLACE FOR MUCH OF THE DAY.
&&
.GRB WATCHES/WARNINGS/ADVISORIES...
WIND CHILL ADVISORY FROM 3 AM WEDNESDAY TO 9 AM CST THURSDAY FOR
WIZ013-020-021-031-037>039-045-048-049-073-074.
WIND CHILL ADVISORY FROM MIDNIGHT TONIGHT TO 9 AM CST THURSDAY
FOR WIZ005-010>012-018-019-030-035-036.
&&
$$
SHORT TERM.....MPC
LONG TERM......KIECKBUSCH
AVIATION.......MPC
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
1136 AM CST TUE DEC 10 2013
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 343 AM CST TUE DEC 10 2013
CURRENTLY AS OF 09Z...WATER VAPOR LOOP AND RAP 500MB HEIGHT
ANALYSIS SHOWED RIDGING OVER THE EAST PACIFIC...TROUGHING OVER
CENTRAL AND EASTERN CANADA AND SOUTHWARD INTO THE UPPER MIDWEST.
WITHIN THIS TROUGH...A POTENT SHORTWAVE WAS NOTED OVER SOUTHWEST
MINNESOTA WHILE ANOTHER SHORTWAVE COULD BE SEEN UPSTREAM IN
CENTRAL ALBERTA. THE STRONG DPVA FORCING AHEAD OF THE POTENT
SHORTWAVE COMBINED WITH ISENTROPIC LIFT AND SOME MOISTURE HAS
HELPED SPREAD CLOUDS ACROSS THE FORECAST AREA. IN ADDITION...LIGHT
SNOW WAS MOVING ACROSS THE FORECAST AREA. ALSO ACCOMPANYING THE
POTENT SHORTWAVE WAS A RELATIVELY DEEP SURFACE LOW CENTERED NEAR
MINNEAPOLIS. THE COMBINATION OF THE CLOUDS AND STRENGTHENING
SOUTHERLY WINDS AHEAD OF THE LOW HAVE HELPED TO BRING TEMPERATURES
UP THROUGH THE NIGHT. MOST WIND CHILLS ARE ABOVE ADVISORY CRITERIA
OF -20F...THUS WE WERE ABLE TO CANCEL TAYLOR/CLARK EARLY.
SIMILARLY...ON THE BACK SIDE OF THE SURFACE LOW WHERE PRESSURES
ARE RISING RAPIDLY...STRONG NORTHWEST WINDS ARE OCCURRING. THESE
ARE ADVECTING IN A BRIEF SURGE OF ARCTIC AIR CHARACTERIZED BY
850MB TEMPS OF -20C PER RAP ANALYSIS. SKIES BEGIN TO CLEAR OUT
QUICKLY TOO ON THE BACK SIDE OF THE LOW.
THE POTENT SHORTWAVE IN MINNESOTA REMAINS PROGGED TO FLY THROUGH THE
FORECAST AREA THIS MORNING...SUCH THAT IT IS ALREADY IN LOWER
MICHIGAN BY 18Z. WHAT THIS MEANS IS WE SHOULD HAVE A BRIEF PERIOD OF
SNOW FOR THE EARLY MORNING HOURS...AFFECTING THE MORNING COMMUTE.
ONCE THE WAVE PASSES...EXPECTING WINDS TO CRANK UP OUT OF THE WEST
AS PRESSURES RISE RAPIDLY. GUSTS ARE LIKELY TO RANGE 25-35 KT WITH
THE PRESSURE RISE COMING IN...HIGHEST IN SOUTHEAST MN. SOME
BLOWING AND DRIFTING OF ALL THE RECENT SNOW IS LIKELY. IT APPEARS
BRISK WINDS WILL PERSIST UNTIL LATE IN THE DAY WHEN A SURFACE
RIDGE BUILDS IN. THE BRISK WINDS WILL ALSO BRING IN COLDER
AIR...CAUSING TEMPS TO FALL...DESPITE INCREASING SUNSHINE.
THE CLEARING THIS AFTERNOON LOOKS TO BE SHORT-LIVED...HOWEVER. THE
NEXT SHORTWAVE OVER ALBERTA IS PROGGED TO DROP DOWN INTO WESTERN
IOWA BY 12Z WEDNESDAY. AS THIS OCCURS...A MID-LEVEL FRONTOGENESIS
BAND WILL SET UP AHEAD OF IT. 10.00Z GFS/NAM/ECMWF/CANADIAN TRACK
THIS BAND FROM SOUTH DAKOTA THIS AFTERNOON INTO FAR SOUTHERN MN AND
NORTHERN IA THIS EVENING...AND FINALLY INTO SOUTHERN WISCONSIN AND
NORTHERN ILLINOIS OVERNIGHT. GIVEN GOOD MODEL CONSENSUS HAVE
RAISED PRECIPITATION CHANCES UP TOWARDS 100 SOUTH OF A LINE FROM
AUSTIN MN TO RICHLAND CENTER WI. MOISTURE IS LIMITED...ON THE
ORDER OF 1 G/KG...BUT THE STRONG FRONTOGENESIS SHOULD BE ABLE TO
SQUEEZE OUT A TENTH OF LIQUID. WITH SNOW TO WATER RATIOS ON THE
ORDER OF 15-20 TO 1...THIS WILL YIELD A QUICK 1 TO 2 INCHES OF
SNOWFALL.
FINALLY...IN THE WAKE OF THAT FRONTOGENESIS BAND...THAT SHORTWAVE
TROUGH LOOKS TO BRING DOWN ANOTHER SURGE OF ARCTIC AIR WITH IT.
850MB TEMPS AFTER BRIEFLY CLIMBING TO -14 TO -18C AHEAD OF THE
BAND...FALL TO -18 TO -22C BY 12Z WEDNESDAY. A TIGHTENING SURFACE
PRESSURE GRADIENT SHOULD YIELD INCREASING NORTH WINDS...ADDING A
WIND CHILL FACTOR. WIND CHILL ADVISORIES HAVE BEEN ISSUED...STARTING
TAYLOR/CLARK AT 06Z AND THEN SOUTHEAST MN AND OTHER WI COUNTIES
NORTH OF I-90 AT 10Z. THE WIND ON TOP OF THE NEW SNOW MAY PRODUCE
SOME BLOWING AND DRIFTING ACROSS NORTHEAST IA TOO LATE IN THE NIGHT.
CLEARING ALSO LOOKS TO ACCOMPANY THE CHILLY AIR.
.LONG TERM...(WEDNESDAY THROUGH MONDAY)
ISSUED AT 343 AM CST TUE DEC 10 2013
PLAN ON A COLD WEDNESDAY. ARCTIC AIR IS FORECAST TO GET DRAGGED INTO
THE FORECAST AREA AS THE SHORTWAVE TROUGH OVER WESTERN IA HEADS
EAST. TEMPS ARE LIKELY TO NOT GET OUT OF THE SINGLE DIGITS ABOVE
ZERO...OR EVEN TO ZERO ACROSS TAYLOR/CLARK COUNTIES. ON TOP OF THE
COLD...A DECENT PRESSURE GRADIENT IN PLACE SHOULD KEEP A NORTHWEST
BREEZE GOING...RESULTING IN WIND CHILLS FROM THE -10 TO -30F RANGE.
THESE COLD WIND CHILLS LOOK TO PERSIST INTO WEDNESDAY EVENING BEFORE
WINDS TURN SOUTHWEST ASSOCIATED WITH A HIGH PRESSURE RIDGE AXIS
PASSAGE. TEMPERATURES ARE FORECAST TO CLIMB AFTER MIDNIGHT IN
RESPONSE TO THIS SOUTHWEST WIND...AS WELL AS INCREASING MID/HIGH
CLOUDS. THESE CLOUDS ARE ASSOCIATED WITH ISENTROPIC LIFT WELL
DOWNSTREAM OF A SHORTWAVE IN MONTANA. ONE QUESTION MARK IS IF ANY
SNOW CAN FORM FROM THIS ISENTROPIC LIFT. MODELS HAVE BEEN GOING BACK
AND FORTH ON THIS...WITH THE 10.00Z ECMWF AND GFS NOW BASICALLY DRY
FOR WEDNESDAY NIGHT AND THURSDAY...WHEREAS THE 10.00Z CANADIAN
MAINTAINS SOME LIGHT PRECIP OVER THE AREA BETWEEN 06-12Z THU. FOR
NOW KEPT A 20 PERCENT CHANCE GOING BETWEEN 06-12Z THURSDAY OVER THE
NORTHEAST PORTION OF THE AREA WITH DRY CONDITIONS BEFORE AND AFTER.
WITH A WARM ADVECTION PATTERN IN PLACE THURSDAY...TEMPERATURES
EXPECTED TO BE MUCH WARMER...ON THE ORDER OF 15-20 DEGREES.
FROM THURSDAY NIGHT INTO FRIDAY...THE UPPER FLOW IS PROGGED TO
BECOME MORE ZONAL OVER THE NORTHERN U.S.. WHAT THIS DOES IS ALLOWS A
FRONTOGENESIS ZONE TO SET UP FROM THE DAKOTAS INTO WISCONSIN. THIS
FRONTOGENESIS FORCING MAY RESULT IN SOME LIGHT SNOW THE ENTIRE
TIME...WITH THE BEST CHANCES STAYING MAINLY NORTH OF THE FORECAST
AREA. DID HONOR SOME 20 PERCENT CHANCES NORTH OF I-94 THURSDAY NIGHT
PER MODEL CONSENSUS. ALSO ON FRIDAY...A SOUTHERN STREAM SHORTWAVE
TROUGH IS SUGGESTED TO MOVE INTO THE CENTRAL PLAINS. FRONTOGENESIS
DOWNSTREAM OF THIS SHORTWAVE TROUGH MAY SPREAD LIGHT PRECIP INTO
SOUTHERN SECTIONS FOR THE FORECAST AREA. FOR NOW KEPT THIS PRECIP
OUT...BUT SOMETHING TO MONITOR. THE SOUTHERN STREAM SYSTEM WILL NEED
EVEN MORE MONITORING AS WE HEAD INTO FRIDAY NIGHT AND SATURDAY.
MODELS ARE SUGGESTING AN INVERTED SURFACE TROUGH ASSOCIATED WITH
THIS SHORTWAVE MOVING THROUGH THE FORECAST AREA. INVERTED TROUGHS
ARE KNOWN TO BRING SNOW...SO PRECIPITATION CHANCES HAVE BEEN RAISED
FOR FRIDAY NIGHT AND SATURDAY. IT SHOULD BE NOTED...THOUGH...THAT
THE BULK OF THE ACCUMULATING SNOW LOOKS TO STAY SOUTHEAST OF THE
AREA.
ANOTHER BRIEF COOL DOWN...BUT NOT AS COLD AS SEEN RECENTLY...IS
SUGGESTED FOR SUNDAY WITH DRY CONDITIONS AS HIGH PRESSURE MOVES
THROUGH. LIGHT WARM ADVECTION SNOWS ARE PROGGED FOR MONDAY AS
ANOTHER NORTHERN STREAM SHORTWAVE TROUGH DROPS DOWN TOWARDS THE
UPPER MIDWEST.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z WEDNESDAY NOON)
ISSUED AT 1136 AM CST TUE DEC 10 2013
GENERALLY GOOD VFR CONDITIONS EXPECTED THIS AFTERNOON. AWOS/ASOS
UNITS ACROSS THE AREA CONTINUE TO REPORT MORE MVFR CIGS THAN
ACTUALLY EXIST. SATELLITE IMAGERY AND SERIES OF WEB/SKY CAMS ACROSS
THE AREA SHOW GENERALLY CLEAR SKIES OVER SOUTHEAST MN/WESTERN WI.
SUBSIDING WINDS HAVE ALLOWED THE BLOWING SNOW TO LAY DOWN TOO.
HOWEVER SOME DRIFTING LIKELY TO PERSIST AT SITES LIKE KRST UNTIL THE
WEST-NORTHWEST WINDS STOP GUSTING.
ANOTHER IN A FAST PARADE OF WEAK LOWS WILL TRACK ACROSS IA TONIGHT
AND SPREAD ANOTHER ROUND OF -SN ACROSS THE TAF SITES. MAINLY IN THE
02Z-08Z PERIOD AT KRST AND 04-10Z AT KLSE AND MAINLY WITH MVFR
CIGS/IFR VSBYS. BOTH SITES LOOK TO RECEIVE 1/2 TO 1 INCH OF FLUFFY
SNOW. WINDS AGAIN INCREASE ONCE THE WEAK LOW PASSES...WITH NORTHWEST
WINDS OF 10-20MPH AND GUSTY LATE TONIGHT/MUCH OF WED MORNING...TO
ONCE AGAIN BLOW THE FRESH SNOW AROUND FOR A FEW HOURS. LOW CLOUDS
EXPECTED TO DECREASE RATHER QUICKLY WED MORNING ONCE THE LOW
PASSES...WITH WINDS DECREASING THRU WED AS THE NEXT WEAK HIGH
BUILDS IN.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
WI...WIND CHILL ADVISORY FROM 4 AM TO NOON CST WEDNESDAY FOR
WIZ032>034-041>044.
WIND CHILL ADVISORY FROM MIDNIGHT TONIGHT TO 6 AM CST THURSDAY
FOR WIZ017-029.
MN...WIND CHILL ADVISORY FROM 4 AM TO NOON CST WEDNESDAY FOR MNZ079-
086>088-094>096.
IA...NONE.
&&
$$
SHORT TERM...AJ
LONG TERM....AJ
AVIATION.....RRS
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
543 AM CST TUE DEC 10 2013
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 343 AM CST TUE DEC 10 2013
CURRENTLY AS OF 09Z...WATER VAPOR LOOP AND RAP 500MB HEIGHT
ANALYSIS SHOWED RIDGING OVER THE EAST PACIFIC...TROUGHING OVER
CENTRAL AND EASTERN CANADA AND SOUTHWARD INTO THE UPPER MIDWEST.
WITHIN THIS TROUGH...A POTENT SHORTWAVE WAS NOTED OVER SOUTHWEST
MINNESOTA WHILE ANOTHER SHORTWAVE COULD BE SEEN UPSTREAM IN
CENTRAL ALBERTA. THE STRONG DPVA FORCING AHEAD OF THE POTENT
SHORTWAVE COMBINED WITH ISENTROPIC LIFT AND SOME MOISTURE HAS
HELPED SPREAD CLOUDS ACROSS THE FORECAST AREA. IN ADDITION...LIGHT
SNOW WAS MOVING ACROSS THE FORECAST AREA. ALSO ACCOMPANYING THE
POTENT SHORTWAVE WAS A RELATIVELY DEEP SURFACE LOW CENTERED NEAR
MINNEAPOLIS. THE COMBINATION OF THE CLOUDS AND STRENGTHENING
SOUTHERLY WINDS AHEAD OF THE LOW HAVE HELPED TO BRING TEMPERATURES
UP THROUGH THE NIGHT. MOST WIND CHILLS ARE ABOVE ADVISORY CRITERIA
OF -20F...THUS WE WERE ABLE TO CANCEL TAYLOR/CLARK EARLY.
SIMILARLY...ON THE BACK SIDE OF THE SURFACE LOW WHERE PRESSURES
ARE RISING RAPIDLY...STRONG NORTHWEST WINDS ARE OCCURRING. THESE
ARE ADVECTING IN A BRIEF SURGE OF ARCTIC AIR CHARACTERIZED BY
850MB TEMPS OF -20C PER RAP ANALYSIS. SKIES BEGIN TO CLEAR OUT
QUICKLY TOO ON THE BACK SIDE OF THE LOW.
THE POTENT SHORTWAVE IN MINNESOTA REMAINS PROGGED TO FLY THROUGH THE
FORECAST AREA THIS MORNING...SUCH THAT IT IS ALREADY IN LOWER
MICHIGAN BY 18Z. WHAT THIS MEANS IS WE SHOULD HAVE A BRIEF PERIOD OF
SNOW FOR THE EARLY MORNING HOURS...AFFECTING THE MORNING COMMUTE.
ONCE THE WAVE PASSES...EXPECTING WINDS TO CRANK UP OUT OF THE WEST
AS PRESSURES RISE RAPIDLY. GUSTS ARE LIKELY TO RANGE 25-35 KT WITH
THE PRESSURE RISE COMING IN...HIGHEST IN SOUTHEAST MN. SOME
BLOWING AND DRIFTING OF ALL THE RECENT SNOW IS LIKELY. IT APPEARS
BRISK WINDS WILL PERSIST UNTIL LATE IN THE DAY WHEN A SURFACE
RIDGE BUILDS IN. THE BRISK WINDS WILL ALSO BRING IN COLDER
AIR...CAUSING TEMPS TO FALL...DESPITE INCREASING SUNSHINE.
THE CLEARING THIS AFTERNOON LOOKS TO BE SHORT-LIVED...HOWEVER. THE
NEXT SHORTWAVE OVER ALBERTA IS PROGGED TO DROP DOWN INTO WESTERN
IOWA BY 12Z WEDNESDAY. AS THIS OCCURS...A MID-LEVEL FRONTOGENESIS
BAND WILL SET UP AHEAD OF IT. 10.00Z GFS/NAM/ECMWF/CANADIAN TRACK
THIS BAND FROM SOUTH DAKOTA THIS AFTERNOON INTO FAR SOUTHERN MN AND
NORTHERN IA THIS EVENING...AND FINALLY INTO SOUTHERN WISCONSIN AND
NORTHERN ILLINOIS OVERNIGHT. GIVEN GOOD MODEL CONSENSUS HAVE
RAISED PRECIPITATION CHANCES UP TOWARDS 100 SOUTH OF A LINE FROM
AUSTIN MN TO RICHLAND CENTER WI. MOISTURE IS LIMITED...ON THE
ORDER OF 1 G/KG...BUT THE STRONG FRONTOGENESIS SHOULD BE ABLE TO
SQUEEZE OUT A TENTH OF LIQUID. WITH SNOW TO WATER RATIOS ON THE
ORDER OF 15-20 TO 1...THIS WILL YIELD A QUICK 1 TO 2 INCHES OF
SNOWFALL.
FINALLY...IN THE WAKE OF THAT FRONTOGENESIS BAND...THAT SHORTWAVE
TROUGH LOOKS TO BRING DOWN ANOTHER SURGE OF ARCTIC AIR WITH IT.
850MB TEMPS AFTER BRIEFLY CLIMBING TO -14 TO -18C AHEAD OF THE
BAND...FALL TO -18 TO -22C BY 12Z WEDNESDAY. A TIGHTENING SURFACE
PRESSURE GRADIENT SHOULD YIELD INCREASING NORTH WINDS...ADDING A
WIND CHILL FACTOR. WIND CHILL ADVISORIES HAVE BEEN ISSUED...STARTING
TAYLOR/CLARK AT 06Z AND THEN SOUTHEAST MN AND OTHER WI COUNTIES
NORTH OF I-90 AT 10Z. THE WIND ON TOP OF THE NEW SNOW MAY PRODUCE
SOME BLOWING AND DRIFTING ACROSS NORTHEAST IA TOO LATE IN THE NIGHT.
CLEARING ALSO LOOKS TO ACCOMPANY THE CHILLY AIR.
.LONG TERM...(WEDNESDAY THROUGH MONDAY)
ISSUED AT 343 AM CST TUE DEC 10 2013
PLAN ON A COLD WEDNESDAY. ARCTIC AIR IS FORECAST TO GET DRAGGED INTO
THE FORECAST AREA AS THE SHORTWAVE TROUGH OVER WESTERN IA HEADS
EAST. TEMPS ARE LIKELY TO NOT GET OUT OF THE SINGLE DIGITS ABOVE
ZERO...OR EVEN TO ZERO ACROSS TAYLOR/CLARK COUNTIES. ON TOP OF THE
COLD...A DECENT PRESSURE GRADIENT IN PLACE SHOULD KEEP A NORTHWEST
BREEZE GOING...RESULTING IN WIND CHILLS FROM THE -10 TO -30F RANGE.
THESE COLD WIND CHILLS LOOK TO PERSIST INTO WEDNESDAY EVENING BEFORE
WINDS TURN SOUTHWEST ASSOCIATED WITH A HIGH PRESSURE RIDGE AXIS
PASSAGE. TEMPERATURES ARE FORECAST TO CLIMB AFTER MIDNIGHT IN
RESPONSE TO THIS SOUTHWEST WIND...AS WELL AS INCREASING MID/HIGH
CLOUDS. THESE CLOUDS ARE ASSOCIATED WITH ISENTROPIC LIFT WELL
DOWNSTREAM OF A SHORTWAVE IN MONTANA. ONE QUESTION MARK IS IF ANY
SNOW CAN FORM FROM THIS ISENTROPIC LIFT. MODELS HAVE BEEN GOING BACK
AND FORTH ON THIS...WITH THE 10.00Z ECMWF AND GFS NOW BASICALLY DRY
FOR WEDNESDAY NIGHT AND THURSDAY...WHEREAS THE 10.00Z CANADIAN
MAINTAINS SOME LIGHT PRECIP OVER THE AREA BETWEEN 06-12Z THU. FOR
NOW KEPT A 20 PERCENT CHANCE GOING BETWEEN 06-12Z THURSDAY OVER THE
NORTHEAST PORTION OF THE AREA WITH DRY CONDITIONS BEFORE AND AFTER.
WITH A WARM ADVECTION PATTERN IN PLACE THURSDAY...TEMPERATURES
EXPECTED TO BE MUCH WARMER...ON THE ORDER OF 15-20 DEGREES.
FROM THURSDAY NIGHT INTO FRIDAY...THE UPPER FLOW IS PROGGED TO
BECOME MORE ZONAL OVER THE NORTHERN U.S.. WHAT THIS DOES IS ALLOWS A
FRONTOGENESIS ZONE TO SET UP FROM THE DAKOTAS INTO WISCONSIN. THIS
FRONTOGENESIS FORCING MAY RESULT IN SOME LIGHT SNOW THE ENTIRE
TIME...WITH THE BEST CHANCES STAYING MAINLY NORTH OF THE FORECAST
AREA. DID HONOR SOME 20 PERCENT CHANCES NORTH OF I-94 THURSDAY NIGHT
PER MODEL CONSENSUS. ALSO ON FRIDAY...A SOUTHERN STREAM SHORTWAVE
TROUGH IS SUGGESTED TO MOVE INTO THE CENTRAL PLAINS. FRONTOGENESIS
DOWNSTREAM OF THIS SHORTWAVE TROUGH MAY SPREAD LIGHT PRECIP INTO
SOUTHERN SECTIONS FOR THE FORECAST AREA. FOR NOW KEPT THIS PRECIP
OUT...BUT SOMETHING TO MONITOR. THE SOUTHERN STREAM SYSTEM WILL NEED
EVEN MORE MONITORING AS WE HEAD INTO FRIDAY NIGHT AND SATURDAY.
MODELS ARE SUGGESTING AN INVERTED SURFACE TROUGH ASSOCIATED WITH
THIS SHORTWAVE MOVING THROUGH THE FORECAST AREA. INVERTED TROUGHS
ARE KNOWN TO BRING SNOW...SO PRECIPITATION CHANCES HAVE BEEN RAISED
FOR FRIDAY NIGHT AND SATURDAY. IT SHOULD BE NOTED...THOUGH...THAT
THE BULK OF THE ACCUMULATING SNOW LOOKS TO STAY SOUTHEAST OF THE
AREA.
ANOTHER BRIEF COOL DOWN...BUT NOT AS COLD AS SEEN RECENTLY...IS
SUGGESTED FOR SUNDAY WITH DRY CONDITIONS AS HIGH PRESSURE MOVES
THROUGH. LIGHT WARM ADVECTION SNOWS ARE PROGGED FOR MONDAY AS
ANOTHER NORTHERN STREAM SHORTWAVE TROUGH DROPS DOWN TOWARDS THE
UPPER MIDWEST.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z WEDNESDAY MORNING)
ISSUED AT 543 AM CST TUE DEC 10 2013
IFR/MVFR CONDITIONS ARE EXPECTED AT THE TAF SITES THIS MORNING
WITH VFR CONDITIONS EXPECTED BY THE LATE MORNING HOURS. A FAST
MOVING AND COMPACT DISTURBANCE WILL MOVE ACROSS THE TAF SITES
EARLY THIS MORNING. WEST/NORTHWEST WINDS WILL INCREASE TO 17 TO 25
KTS WITH GUSTS TO AROUND 33 KTS POSSIBLE. THIS WILL LEAD TO AREAS
OF BLOWING SNOW...POSSIBLY REDUCING VISIBILITIES TO AROUND 4SM AT
TIMES. A BRIEF PERIOD OF IFR VISIBILITIES ARE POSSIBLE IN THE
BLOWING SNOW THIS MORNING AT KRST. SKIES WILL CLEAR BY THE MID TO
LATE MORNING HOURS WITH VFR CONDITIONS EXPECTED THROUGH THE
AFTERNOON. ANOTHER SYSTEM WILL MOVE ACROSS THE REGION TONIGHT
BRINGING LIGHT SNOW AND IFR CONDITIONS TO THE TAF SITES.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
WI...WIND CHILL ADVISORY FROM 4 AM TO NOON CST WEDNESDAY FOR
WIZ032>034-041>044.
WIND CHILL ADVISORY FROM MIDNIGHT TONIGHT TO 6 AM CST THURSDAY
FOR WIZ017-029.
MN...WIND CHILL ADVISORY FROM 4 AM TO NOON CST WEDNESDAY FOR MNZ079-
086>088-094>096.
IA...NONE.
&&
$$
SHORT TERM...AJ
LONG TERM...AJ
AVIATION...WETENKAMP
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
343 AM CST TUE DEC 10 2013
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 343 AM CST TUE DEC 10 2013
CURRENTLY AS OF 09Z...WATER VAPOR LOOP AND RAP 500MB HEIGHT
ANALYSIS SHOWED RIDGING OVER THE EAST PACIFIC...TROUGHING OVER
CENTRAL AND EASTERN CANADA AND SOUTHWARD INTO THE UPPER MIDWEST.
WITHIN THIS TROUGH...A POTENT SHORTWAVE WAS NOTED OVER SOUTHWEST
MINNESOTA WHILE ANOTHER SHORTWAVE COULD BE SEEN UPSTREAM IN
CENTRAL ALBERTA. THE STRONG DPVA FORCING AHEAD OF THE POTENT
SHORTWAVE COMBINED WITH ISENTROPIC LIFT AND SOME MOISTURE HAS
HELPED SPREAD CLOUDS ACROSS THE FORECAST AREA. IN ADDITION...LIGHT
SNOW WAS MOVING ACROSS THE FORECAST AREA. ALSO ACCOMPANYING THE
POTENT SHORTWAVE WAS A RELATIVELY DEEP SURFACE LOW CENTERED NEAR
MINNEAPOLIS. THE COMBINATION OF THE CLOUDS AND STRENGTHENING
SOUTHERLY WINDS AHEAD OF THE LOW HAVE HELPED TO BRING TEMPERATURES
UP THROUGH THE NIGHT. MOST WIND CHILLS ARE ABOVE ADVISORY CRITERIA
OF -20F...THUS WE WERE ABLE TO CANCEL TAYLOR/CLARK EARLY.
SIMILARLY...ON THE BACK SIDE OF THE SURFACE LOW WHERE PRESSURES
ARE RISING RAPIDLY...STRONG NORTHWEST WINDS ARE OCCURRING. THESE
ARE ADVECTING IN A BRIEF SURGE OF ARCTIC AIR CHARACTERIZED BY
850MB TEMPS OF -20C PER RAP ANALYSIS. SKIES BEGIN TO CLEAR OUT
QUICKLY TOO ON THE BACK SIDE OF THE LOW.
THE POTENT SHORTWAVE IN MINNESOTA REMAINS PROGGED TO FLY THROUGH THE
FORECAST AREA THIS MORNING...SUCH THAT IT IS ALREADY IN LOWER
MICHIGAN BY 18Z. WHAT THIS MEANS IS WE SHOULD HAVE A BRIEF PERIOD OF
SNOW FOR THE EARLY MORNING HOURS...AFFECTING THE MORNING COMMUTE.
ONCE THE WAVE PASSES...EXPECTING WINDS TO CRANK UP OUT OF THE WEST
AS PRESSURES RISE RAPIDLY. GUSTS ARE LIKELY TO RANGE 25-35 KT WITH
THE PRESSURE RISE COMING IN...HIGHEST IN SOUTHEAST MN. SOME
BLOWING AND DRIFTING OF ALL THE RECENT SNOW IS LIKELY. IT APPEARS
BRISK WINDS WILL PERSIST UNTIL LATE IN THE DAY WHEN A SURFACE
RIDGE BUILDS IN. THE BRISK WINDS WILL ALSO BRING IN COLDER
AIR...CAUSING TEMPS TO FALL...DESPITE INCREASING SUNSHINE.
THE CLEARING THIS AFTERNOON LOOKS TO BE SHORT-LIVED...HOWEVER. THE
NEXT SHORTWAVE OVER ALBERTA IS PROGGED TO DROP DOWN INTO WESTERN
IOWA BY 12Z WEDNESDAY. AS THIS OCCURS...A MID-LEVEL FRONTOGENESIS
BAND WILL SET UP AHEAD OF IT. 10.00Z GFS/NAM/ECMWF/CANADIAN TRACK
THIS BAND FROM SOUTH DAKOTA THIS AFTERNOON INTO FAR SOUTHERN MN AND
NORTHERN IA THIS EVENING...AND FINALLY INTO SOUTHERN WISCONSIN AND
NORTHERN ILLINOIS OVERNIGHT. GIVEN GOOD MODEL CONSENSUS HAVE
RAISED PRECIPITATION CHANCES UP TOWARDS 100 SOUTH OF A LINE FROM
AUSTIN MN TO RICHLAND CENTER WI. MOISTURE IS LIMITED...ON THE
ORDER OF 1 G/KG...BUT THE STRONG FRONTOGENESIS SHOULD BE ABLE TO
SQUEEZE OUT A TENTH OF LIQUID. WITH SNOW TO WATER RATIOS ON THE
ORDER OF 15-20 TO 1...THIS WILL YIELD A QUICK 1 TO 2 INCHES OF
SNOWFALL.
FINALLY...IN THE WAKE OF THAT FRONTOGENESIS BAND...THAT SHORTWAVE
TROUGH LOOKS TO BRING DOWN ANOTHER SURGE OF ARCTIC AIR WITH IT.
850MB TEMPS AFTER BRIEFLY CLIMBING TO -14 TO -18C AHEAD OF THE
BAND...FALL TO -18 TO -22C BY 12Z WEDNESDAY. A TIGHTENING SURFACE
PRESSURE GRADIENT SHOULD YIELD INCREASING NORTH WINDS...ADDING A
WIND CHILL FACTOR. WIND CHILL ADVISORIES HAVE BEEN ISSUED...STARTING
TAYLOR/CLARK AT 06Z AND THEN SOUTHEAST MN AND OTHER WI COUNTIES
NORTH OF I-90 AT 10Z. THE WIND ON TOP OF THE NEW SNOW MAY PRODUCE
SOME BLOWING AND DRIFTING ACROSS NORTHEAST IA TOO LATE IN THE NIGHT.
CLEARING ALSO LOOKS TO ACCOMPANY THE CHILLY AIR.
.LONG TERM...(WEDNESDAY THROUGH MONDAY)
ISSUED AT 343 AM CST TUE DEC 10 2013
PLAN ON A COLD WEDNESDAY. ARCTIC AIR IS FORECAST TO GET DRAGGED INTO
THE FORECAST AREA AS THE SHORTWAVE TROUGH OVER WESTERN IA HEADS
EAST. TEMPS ARE LIKELY TO NOT GET OUT OF THE SINGLE DIGITS ABOVE
ZERO...OR EVEN TO ZERO ACROSS TAYLOR/CLARK COUNTIES. ON TOP OF THE
COLD...A DECENT PRESSURE GRADIENT IN PLACE SHOULD KEEP A NORTHWEST
BREEZE GOING...RESULTING IN WIND CHILLS FROM THE -10 TO -30F RANGE.
THESE COLD WIND CHILLS LOOK TO PERSIST INTO WEDNESDAY EVENING BEFORE
WINDS TURN SOUTHWEST ASSOCIATED WITH A HIGH PRESSURE RIDGE AXIS
PASSAGE. TEMPERATURES ARE FORECAST TO CLIMB AFTER MIDNIGHT IN
RESPONSE TO THIS SOUTHWEST WIND...AS WELL AS INCREASING MID/HIGH
CLOUDS. THESE CLOUDS ARE ASSOCIATED WITH ISENTROPIC LIFT WELL
DOWNSTREAM OF A SHORTWAVE IN MONTANA. ONE QUESTION MARK IS IF ANY
SNOW CAN FORM FROM THIS ISENTROPIC LIFT. MODELS HAVE BEEN GOING BACK
AND FORTH ON THIS...WITH THE 10.00Z ECMWF AND GFS NOW BASICALLY DRY
FOR WEDNESDAY NIGHT AND THURSDAY...WHEREAS THE 10.00Z CANADIAN
MAINTAINS SOME LIGHT PRECIP OVER THE AREA BETWEEN 06-12Z THU. FOR
NOW KEPT A 20 PERCENT CHANCE GOING BETWEEN 06-12Z THURSDAY OVER THE
NORTHEAST PORTION OF THE AREA WITH DRY CONDITIONS BEFORE AND AFTER.
WITH A WARM ADVECTION PATTERN IN PLACE THURSDAY...TEMPERATURES
EXPECTED TO BE MUCH WARMER...ON THE ORDER OF 15-20 DEGREES.
FROM THURSDAY NIGHT INTO FRIDAY...THE UPPER FLOW IS PROGGED TO
BECOME MORE ZONAL OVER THE NORTHERN U.S.. WHAT THIS DOES IS ALLOWS A
FRONTOGENESIS ZONE TO SET UP FROM THE DAKOTAS INTO WISCONSIN. THIS
FRONTOGENESIS FORCING MAY RESULT IN SOME LIGHT SNOW THE ENTIRE
TIME...WITH THE BEST CHANCES STAYING MAINLY NORTH OF THE FORECAST
AREA. DID HONOR SOME 20 PERCENT CHANCES NORTH OF I-94 THURSDAY NIGHT
PER MODEL CONSENSUS. ALSO ON FRIDAY...A SOUTHERN STREAM SHORTWAVE
TROUGH IS SUGGESTED TO MOVE INTO THE CENTRAL PLAINS. FRONTOGENESIS
DOWNSTREAM OF THIS SHORTWAVE TROUGH MAY SPREAD LIGHT PRECIP INTO
SOUTHERN SECTIONS FOR THE FORECAST AREA. FOR NOW KEPT THIS PRECIP
OUT...BUT SOMETHING TO MONITOR. THE SOUTHERN STREAM SYSTEM WILL NEED
EVEN MORE MONITORING AS WE HEAD INTO FRIDAY NIGHT AND SATURDAY.
MODELS ARE SUGGESTING AN INVERTED SURFACE TROUGH ASSOCIATED WITH
THIS SHORTWAVE MOVING THROUGH THE FORECAST AREA. INVERTED TROUGHS
ARE KNOWN TO BRING SNOW...SO PRECIPITATION CHANCES HAVE BEEN RAISED
FOR FRIDAY NIGHT AND SATURDAY. IT SHOULD BE NOTED...THOUGH...THAT
THE BULK OF THE ACCUMULATING SNOW LOOKS TO STAY SOUTHEAST OF THE
AREA.
ANOTHER BRIEF COOL DOWN...BUT NOT AS COLD AS SEEN RECENTLY...IS
SUGGESTED FOR SUNDAY WITH DRY CONDITIONS AS HIGH PRESSURE MOVES
THROUGH. LIGHT WARM ADVECTION SNOWS ARE PROGGED FOR MONDAY AS
ANOTHER NORTHERN STREAM SHORTWAVE TROUGH DROPS DOWN TOWARDS THE
UPPER MIDWEST.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z TUESDAY NIGHT)
ISSUED AT 1100 PM CST MON DEC 9 2013
UPPER LEVEL SHORTWAVE WILL DRIVE SOUTHEAST ACROSS THE REGION DURING
THE OVERNIGHT/EARLY MORNING HOURS...BRINGING LOWERING CIGS AND SOME
-SN. SNOW LOOKS MOST LIKELY BETWEEN 09-14Z FOR KRST/KLSE WITH VSBY
RESTRICTIONS DOWN TO 2SM...POSSIBLY LOWER FOR A BRIEF TIME. CURRENT
OBSERVATIONS ACROSS THE DAKOTAS MOSTLY INDICATING MVFR CIGS WITH
THIS SYSTEM. CAN/T RULE OUT SOME SUB 1 KFT CIGS...BUT GOING TO KEEP
MVFR FOR NOW.
WINDS WILL INCREASE FROM THE WEST BY 15Z AS THE SYSTEM/S SFC LOW
SLIDES ACROSS WI. THERE IS SOME CONCERN OF BLSN AT KRST...BUT NOT
EXPECTING MORE THAN 1/2 INCH OF FRESH SNOW...AND WHAT FELL YESTERDAY
HAS ALREADY BLOWN AROUND. GOING TO LEAVE OUT OF THE FORECAST FOR
NOW...BUT TRENDS WILL HAVE TO BE MONITORED. SOME 4-5SM ISN/T OUT OF
THE QUESTION.
LOOKING FOR CLEARING BY THE AFTERNOON...BUT ANOTHER UPPER LEVEL
SHORTWAVE WILL BE DROPPING ACROSS IA STARTING TUE EVENING. CLOUDS
WILL RETURN...WITH LOWER CIGS AND SOME -SN. GREATER CHANCES TO THE
SOUTH...BUT KRST/KLSE APPEAR CLOSE ENOUGH TO THE NORTHERN FRINGE
WHERE A FEW HOURS OF -SN AND MVFR CIGS ARE LIKELY FOR LATE
EVENING/OVERNIGHT.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
WI...WIND CHILL ADVISORY FROM 4 AM TO NOON CST WEDNESDAY FOR
WIZ032>034-041>044.
WIND CHILL ADVISORY FROM MIDNIGHT TONIGHT TO 6 AM CST THURSDAY
FOR WIZ017-029.
MN...WIND CHILL ADVISORY FROM 4 AM TO NOON CST WEDNESDAY FOR MNZ079-
086>088-094>096.
IA...NONE.
&&
$$
SHORT TERM...AJ
LONG TERM...AJ
AVIATION.....RIECK
AREA FORECAST DISCUSSION
NWS GREEN BAY WI
1050 PM CST MON DEC 9 2013
UPDATED AVIATION PORTION FOR 06Z TAF ISSUANCE
.SHORT TERM...TONIGHT AND TUESDAY
ISSUED AT 247 PM CST MON DEC 9 2013
LATEST RUC ANALYSIS AND SATELLITE/RADAR IMAGERY SHOW A BROAD AREA OF
LOW PRESSURE MOVING NORTHEAST OVER NORTHERN ONTARIO AND A SURFACE
RIDGE AXIS SHIFTING EAST OVER THE NORTHERN PLAINS. BETWEEN THE TWO
SYSTEMS...WEST WINDS IS DRIVING ARCTIC AIR ACROSS THE STATE...AND
TEMPERATURES ARE DROPPING ACROSS CENTRAL AND NORTH-CENTRAL
WISCONSIN. NO CHANGE IN THE START OF TIME OF WIND CHILL
HEADLINES...AS THEY ARE ALREADY APPROACHING CRITERIA AT RHINELANDER.
THE LEADING EDGE OF THIS ARCTIC AIR IS MARKED BY A BAND OF STRATO-CU
AND ACCOMPANYING LIGHT SNOW SHOWERS/FLURRIES...WHICH IS NOW ENTERING
NORTHEAST WISCONSIN. ANTICIPATE THE SNOW SHOWERS/FLURRIES TO
DIMINISH LATER THIS AFTERNOON ONCE THE SUN GOES DOWN AND ANY DIURNAL
INSTABILITY IS LOST. ATTENTION THEN TURNS TO A FAST MOVING CLIPPER
SYSTEM WHICH IS DIVING SE OVER SOUTHERN SASKATCHEWAN THIS
AFTERNOON. THE CLIPPER LOOKS DECENT ON SATELLITE IMAGERY AND THERE
ARE PLENTY OF OBS OVER WESTERN NORTH DAKOTA AND EASTERN MONTANA
SHOWING LIGHT TO MODERATE SNOW. SO THE FORECAST CONCERNS START OUT
WITH WIND CHILLS TONIGHT...AND SNOW POTENTIAL WITH THE CLIPPER LATE
TONIGHT INTO TUESDAY MORNING.
TONIGHT...HIGH PRESSURE RIDGE AXIS WILL MOVE EAST INTO CENTRAL
WISCONSIN THIS EVENING AND ACROSS EASTERN WISCONSIN OVERNIGHT.
ALONG WITH THE LOSS OF DAYTIME HEATING...THIS WILL HELP SKIES CLEAR
AND LIGHT SNOW/FLURRIES COME TO AN END LATE IN THE AFTERNOON OR
EARLY THIS EVENING. ARCTIC AIR WILL CONTINUE TO POUR ACROSS THE
REGION DURING THE EVENING...AND THE CLEARING SKIES WILL PROMOTE
TEMPS FALLING QUICKLY WITH LOWS OCCURRING NEAR OR SHORTLY AFTER
MIDNIGHT. THEN ALL EYES WILL BE ON A FAST MOVING CLIPPER PROGGED TO
ENTER THE STATE LATE TONIGHT. THE LATEST MODEL RUNS HAVE TRENDED A
FEW HOURS SLOWER...AND NOW START BRINGING IT INTO THE STATE AFTER
09Z. THE VORT WILL BRING EXCELLENT MID-LEVEL FORCING...SO WILL
INCREASE POPS BY 12Z DESPITE A SEVERE LACK OF MOISTURE. WITH THE
LATER ARRIVAL OF THE CLIPPER...WIND CHILL READINGS WILL REMAIN NEAR
THE 20 BELOW CRITERIA OVER CENTRAL AND NORTH-CENTRAL WISCONSIN
THROUGH THE 12Z HOUR SO NO CHANGE IN HEADLINES ANTICIPATED. TEMPS
WILL REBOUND SOMEWHAT WITH THE INCREASING CLOUDS OVERNIGHT.
TUESDAY...THE CLIPPER WILL QUICKLY ADVANCE EAST ACROSS THE AREA
TUESDAY MORNING. THE STRONG FORCING AND POCKET OF INSTABILITY IN
THE MID-LEVELS SHOULD BRING A FEW TENTHS OF DRY FLUFFY SNOW ACROSS
THE ENTIRE FORECAST AREA BEFORE IT RAPIDLY PULLS OUT BY LATE IN THE
MORNING OR EARLY AFTERNOON. ANOTHER SURGE OF ARCTIC AIR WILL FOLLOW
IN THE WAKE OF THE CLIPPER...WITH STEEPENING LOW LEVEL LAPSE RATES
AND ENHANCED LOW LEVEL RH. WOULDNT BE SURPRISED TO SEE INSTABILITY
SNOW SHOWERS/FLURRIES REDEVELOP IN THE AFTERNOON...SIMILAR TO THE
SNOW SHOWERS ONGOING TODAY. WILL LET THE NEXT SHIFT EVALUATE BEFORE
ADDING THEM TO THE FORECAST. HIGHS FROM THE MIDDLE SINGLE DIGITS
NORTH TO THE MIDDLE TEENS EAST.
.LONG TERM...TUESDAY NIGHT THROUGH MONDAY
ISSUED AT 247 PM CST MON DEC 9 2013
COLD TEMPERATURES/WIND CHILLS AND PCPN CHANCES ARE THE MAIN FCST
CONCERNS.
A REINFORCING SHOT OF ARCTIC AIR WILL BE IN PLACE TUES NGT INTO
WEDS...WITH H8 TEMPS OF -20 TO -25 C OVER THE FORECAST AREA. LOW-
LEVEL WINDS WILL BE WEST-NORTHWEST...SO LAKE EFFECT IMPACT WILL BE
MINIMAL...WITH JUST A FEW SNOW SHOWERS OR FLURRIES EXPECTED OVER
VILAS COUNTY. A S/W TROF AND THE RRQ OF A JET STREAK WILL QUICKLY
SWEEP THROUGH THE SOUTHERN PART OF GRB CWA ON TUES NGT...SO KEPT
CHC POPS OVER C/EC WI. CLOUDS ASSOCIATED WITH THIS SYSTEM AND ANY
LAKE-INDUCED CLOUDS OVER THE FAR NORTH COULD HAVE A BIG IMPACT ON
MIN TEMPS. USED A BLEND OF THE PREV FCST...ECMWF AND A FEW OTHER
TOP PERFORMING GUIDANCE SETS...AND MADE A FEW TWEEKS TO ACCOUNT
FOR CLOUD TRENDS. WILL HAVE COLDEST MIN TEMPS (-15 TO -17 F) IN
THE TOMAHAWK/RHINELANDER/CRANDON REGION...WITH SINGLE DIGITS
BELOW ZERO OVER OUR SOUTHERN/EASTERN COUNTIES...EXCEPT SINGLE
DIGITS ABOVE ZERO ALONG THE LKSHR. HIGH TEMPS ON WEDS WILL BE IN
THE 5 BELOW TO 5 ABOVE RANGE IN MOST AREAS...COLDEST OVER NC WI.
WIND CHILLS LOOK LIKE THEY WILL DROP INTO THE -20 TO -30 RANGE
NORTHWEST OF A LINE FROM ISW-IMT TUES NGT INTO WEDS...AND OVER
MOST OF THE CWA ON WED NGT...SO ADDITIONAL WIND CHILL ADVISORIES
MAY BE NEEDED.
WAA WILL DEVELOP LATE WEDS NGT INTO THURSDAY...AND WILL PROBABLY
GENERATE SOME LIGHT SNOW OR FLURRIES. SOME MODERATION IN TEMPS
IS ANTICIPATED...WITH HIGHS REACHING THE UPPER SINGLE DIGITS
AND TEENS.
THE ARCTIC BAROCLINIC ZONE WILL RESIDE OVER THE REGION THROUGH
MUCH...IF NOT ALL...OF THE EXTENDED FORECAST. TEMPERATURES
WILL REMAIN BLO NORMAL. WITH STRONG WEST-NORTHWEST FLOW ALOFT
IN PLACE DURING THE PERIOD...SEVERAL JET STREAKS/SHORT-WAVE TROFS
WILL PASS THROUGH THE GREAT LAKES REGION. THE RRQ OF A JET STREAK
WILL PASS THROUGH THE REGION THU NGT AND FRI...AND MODELS ARE
HINTING AT AN INVERTED SFC TROF AFFECTING THE REGION FRI NGT/SAT...
AND POSSIBLY LINGERING OVER THE RGN INTO SUNDAY. ANY OF THESE
DISTURBANCES COULD PRODUCE LIGHT SNOW OR FLURRIES...SO ALMOST
EVERY PERIOD OF THE FCST HAS SLGT CHC/CHC POPS. HOPEFULLY IN THE
NEXT FEW DAYS WE WILL BE ABLE TO BETTER DEFINE WHICH OF THESE
SYSTEMS WILL HAVE THE MOST IMPACT ACROSS THE REGION.
&&
.AVIATION...FOR 06Z TAF ISSUANCE
ISSUED AT 1035 PM CST MON DEC 9 2013
WHILE A RIDGE OF HIGH PRESSURE SLIDES EAST OF THE REGION
OVERNIGHT A CLIPPER SYSTEM WILL APPROACH THE STATE. MID TO HIGH
LEVEL CLOUDS WILL SWEEP OVER THE REGION FOR THE EARLY MORNING
HOURS. THEN A PERIOD OF MVFR CIGS WITH PERHAPS A 2 HOUR PERIOD
IFR VSBYS DUE TO SNOW SHOWERS AND BLSN MAY BE ASSOCIATED WITH
ANOTHER ARCTIC COLD FRONT PASSAGE. GUSTY WEST WINDS WITH AREAS OF
BLSN WILL THEN CONTINUE FOR THE REST OF TUESDAY BEFORE DIMINISHING
LATE IN THE DAY FROM WEST TO EAST ALONG WITH IMPROVING CIGS TO VFR
CONDITIONS BY TUESDAY NIGHT.
&&
.GRB WATCHES/WARNINGS/ADVISORIES...
WIND CHILL ADVISORY UNTIL 6 AM CST TUESDAY FOR WIZ005-010>013-
018>021-030-031-035>037.
&&
$$
SHORT TERM.....MPC
LONG TERM......KIECKBUSCH
AVIATION.......TDH
AREA FORECAST DISCUSSION
NWS TAMPA BAY RUSKIN FL
355 AM EST THU DEC 12 2013
.SYNOPSIS...
08Z WATER VAPOR AND H4 RAP ANALYSIS SHOWS A MID/UPPER LEVEL PATTERN
CHARACTERIZED BY A REX BLOCK STRUCTURE OVER THE PACIFIC COAST...
FOLLOWED DOWNSTREAM BY CONVERGENT FLOW FROM EITHER SIDE OF THIS
BLOCK COMING TOGETHER OVER THE CENTRAL PLAINS TO RESULT IN SOUTHERN
STREAM ZONAL FLOW ALONG THE NORTHERN GULF COAST AND BROAD LONGWAVE
NORTHERN STREAM TROUGHING OVER MUCH OF THE EASTERN HALF OF THE
NATION. OUR FORECAST AREA NOW RESIDES WITHIN THIS MAINLY WESTERLY
ZONAL FLOW ALOFT...AND THIS WAS SAMPLED WELL ABOVE 700MB ON THE
12/00Z KTBW SOUNDING PROFILE. ONE WEAK SHORTWAVE PROGRESSING DOWN
THE BACKSIDE OF THE TROUGH AND CLEARLY DEFINED WITH
DRYING/SUBSIDENCE OVER OKLAHOMA WILL QUICKLY TRANSLATE SOUTHEASTWARD
TOWARD THE REGION LATER TODAY AND TONIGHT AND HELP TO SCOUR OUT EVEN
MORE OF OUR MOISTURE ALOFT. WITHIN THE MAIN LONGWAVE TROUGH THIS
PATTERN CURRENTLY IS RESULTING IN A COLD FORECAST FOR MUCH OF THE
EASTERN CONUS...BUT ALSO GENERALLY BENIGN WEATHER WITH A BROAD
EXPANSE OF SURFACE HIGH PRESSURE OVER MS/OH/TN VALLEYS AND NO
SIGNIFICANT FORCING ALOFT.
THIS QUIET PATTERN WILL NOT LAST ALL THAT LONG THROUGH AS THE
CUT-OFF LOW NEAR THE BAJA REGION/SOUTHERN CALIFORNIA IS PROGGED TO
OPEN UP AND BECOME PROGRESSIVE WITHIN THE SOUTHERN STREAM FLOW ON
FRIDAY.
NEAR AT THE SURFACE...NORTHEAST FLOW AND ABUNDANT BOUNDARY LAYER
MOISTURE HAS ALLOWED THE DEVELOPMENT OF A LARGE EXPANSE OF LOWER
STRATUS FROM THE I-4 CORRIDOR NORTHWARD. THE SREF AND NARRE GUIDANCE
HAS BEEN HANDLING THIS STRATUS VERY WELL OVERNIGHT AND USED THESE
SOLUTIONS FOR CLOUD COVER THROUGH THE MORNING HOURS. AS MENTIONED
ABOVE...A LARGE EXPANSE OF 1030MB+ HIGH PRESSURE IS CENTERED TO OUR
NORTHWEST NEAR THE MIDDLE MS VALLEY. A WEAK AND NOW QUASI-STATIONARY
COLD FRONT IS CURRENTLY SITUATED TO THE SOUTH OF THE I-4 CORRIDOR
DOWN TOWARD CHARLOTTE AND LEE COUNTIES. THE APPROACH AND MASS FIELDS
PUSH ASSOCIATED WITH THE WEAK SHORTWAVE ARRIVING LATER TODAY WILL
HELP TO FINALLY "SHOVE" THIS BOUNDARY WELL TO THE SOUTH OF OUR
ZONES.
&&
.SHORT TERM (TODAY THROUGH SATURDAY)...
TODAY AND TONIGHT...
AREAS OF LOW STRATUS OVER THE NORTHERN AND CENTRAL ZONES SHOULD MOVE
AND ERODE SOUTHWARD AS DRIER AIR BEGINS TO QUICKLY FILTER IN FROM
THE NORTH DURING THE MORNING HOURS. THEREFORE AREAS OF MOSTLY CLOUDY
SKIES TO START THE DAY SHOULD SCATTER OUT FOR THE SECOND HALF OF THE
DAY. THE MOST ABUNDANT CLOUD POTENTIAL FOR THE AFTERNOON SHOULD BE
SOUTH OF TAMPA BAY. AS WEAK SHORTWAVE ENERGY APPROACHES AND PASSES
THROUGH THE REGION TODAY...THE COOLER AND DRIER AIRMASS BEHIND THE
COLD FRONT WILL FINALLY BEGIN TO ARRIVE. HIGH TEMPERATURES TODAY
WILL RANGE FROM THE UPPER 60S FOR LEVY COUNTY TO THE LOWER/MID 70S
AROUND I-4...AND MID TO UPPER 70S FURTHER SOUTH. THE LOW LEVEL
MOISTURE WILL STILL BE IN PLACE LATE THIS MORNING AND EARLY
AFTERNOON AROUND HIGHLANDS COUNTY...AND WITH DEVELOPING NORTHEAST
FLOW...A SPEED CONVERGENCE SPRINKLES OR 2 IS POSSIBLE...BUT
MEASURABLE RAINFALL IS REALLY NOT EXPECTED.
A DRY COLUMN DESCENDS UPON THE REGION OVERNIGHT AS THE RIDGE OF HIGH
PRESSURE PASSES THROUGH GA AND THE CAROLINAS. IT WILL BE A
NOTICEABLY COOLER NIGHT THAN WHAT WE HAVE EXPERIENCED LATELY. THE
RIDGE IS TOO FAR NORTH FOR ANY REAL DE-COUPLING OF THE BOUNDARY
LAYER AND EFFICIENT RADIATIONAL COOLING FOR MOST OF THE REGION...BUT
STILL EXPECTING MANY SPOTS NORTH OF I-4 TO DROP INTO THE 40S WITH
UPPER 40S TO LOW 50S COMMON FURTHER SOUTH. THE COLDEST TEMPS WILL BE
UP TOWARD LEVY COUNTY WHERE THE CLOSEST PROXIMITY TO THE RIDGE AND
GOOD DRAINAGE SETUP SHOULD ALLOW TEMPERATURES TO DROP INTO THE
MID/UPPER 30S. AS OF RIGHT NOW...DO NOT EXPECT ANY SUB-FREEZING
TEMPERATURES...HOWEVER...IF WINDS CAN GO CALM FOR A FEW HOURS AROUND
SUNRISE...THEN THERE WILL BE THE THREAT OF PATCHY FROST. HAVE ADDED
PATCHY FROST TO THE FORECAST FOR ALL AREAS FORECAST TO REACH 36
DEGREES OR BELOW FOR THE FEW HOURS SURROUNDING SUNRISE.
FRIDAY/FRIDAY NIGHT...
FRIDAY IS SHAPING UP TO BE A VERY PLEASANT END TO THE WORK WEEK AS
OUR LOW LEVEL FLOW BECOMES EASTERLY UNDERNEATH A ZONAL FLOW
PATTERN ALOFT. OUR NEXT SYSTEM FOR THE WEEKEND WILL STILL BE WELL TO
OUR WEST OVER THE SOUTHERN PLAINS. WITH A DRY COLUMN AND LITTLE TO
NO SYNOPTIC FORCING TO SPEAK OF...WILL SHOW A RAIN FREE FORECAST.
WITH THE EASTERLY FLOW DELVING SOME ATLANTIC MOISTURE...WOULD
ANTICIPATE MOSTLY CLEAR SKIES GIVING WAY TO A SCT-BKN FAIR WEATHER
CUMULUS FIELD DURING THE AFTERNOON. ENOUGH MOISTURE RETURN WILL
HAVE OCCURRED BY FRIDAY NIGHT TO RESULT IN A MUCH WARMER FORECAST
THAN THURSDAY NIGHT. MOST LOCATIONS SHOULD STAY IN THE UPPER 50S TO
LOWER 60S...WITH SOME COOLER LOWER TO MIDDLE 50S FOR OUR NORTHERN
NATURE COAST ZONES.
SATURDAY...
OVERALL A WARM AND GENERALLY DRY DAY EXPECTED FOR THE FIRST HALF OF
THE UPCOMING WEEKEND. SHORTWAVE ENERGY WILL EJECT EASTWARD ACROSS
THE TN VALLEY DRAGGING A WEAK WAVE LOW LOW PRESSURE NORTHWARD FROM
THE CENTRAL GULF COAST. A COLD FRONT WILL EXTEND SOUTH FROM THIS
FEATURE INTO THE CENTRAL GULF...BUT ONLY MOVE SLOWLY EASTWARD
THROUGH THE DAY. THROUGH THE DAYLIGHT HOURS OF SATURDAY...OUR REGION
SIMPLY REMAINS AHEAD OF ANY RESPECTABLE SYNOPTIC FORCING AND UNDER
UNFAVORABLE UPPER JET PLACEMENT. AS THE FRONT SLOWLY DRAGS
EASTWARD...HAVE KEPT A CHANCE FOR A FEW SHOWER OR A THUNDERSTORM UP
TOWARD LEVY COUNTY LATE IN THE AFTERNOON...BUT EVEN THIS MAY BE
AGGRESSIVE ON THE TIMING. ELSEWHERE...OTHER THAN A BRIEF INSTABILITY
SHOWER...THE FORECAST IS DRY WITH ABOVE NORMAL TEMPERATURES. THIS
FRONT EVEN BEYOND SATURDAY DOES NOT LOOK TO BE MUCH OF A RAIN
PRODUCER OTHER THAN FOR OUR FAR NORTHERN ZONES. BY SATURDAY
NIGHT...THE MAIN ENERGY ASSOCIATED WITH THE UPPER IMPULSE WILL BE
SHIFTING TO NEW CYCLOGENESIS ALONG THE MID-ATLANTIC BAROCLINIC ZONE.
THIS TRANSLATION OF ENERGY AWAY FOR THE FL PENINSULA IS A COMMON
OCCURRENCE DURING THE COOL SEASON. THE RESULT FOR OUR REGION IS A
REDISTRIBUTION OF THE SYNOPTIC FORCING TO THE NORTH AND A STRETCHING
(LESS FOCUS) OF THE TRAILING FRONTAL FEATURE. THE DECREASE OF ALL
THE FORCING RESULTS IN AN UNORGANIZED OR BROKEN BAND OF GENERALLY
UNIMPRESSIVE CONVECTION ALONG THE FRONT FOR SATURDAY NIGHT INTO
SUNDAY.
&&
.LONG TERM (SUNDAY THROUGH NEXT THURSDAY)...
A BROAD UPPER LEVEL TROUGH FROM THE GREAT LAKES TO THE SOUTHERN
PLAINS SLOWLY MOVES TO THE EASTERN SEABOARD BY MON WITH THE FLOW
ALOFT VEERING FROM SOUTHWEST TO WEST-NORTHWEST. AT THE SURFACE A LOW
ON THE CENTRAL GULF COAST...WITH A COLD FRONT TRAILING BACK ACROSS
THE WESTERN GULF...TRACKS TO THE NORTHEAST. THE LOW REACHES THE
COASTAL WATERS OF THE CANADIAN MARITIMES MON AS THE FRONT SLIDES
ACROSS THE GULF AND INTO SOUTH FL.
FOR TUE-WED...THE BROAD TROUGH CONTINUES OVER THE EASTERN STATES AS
A SHORT WAVE TROUGH DROP OUT OF CENTRAL CANADA TO THE GREAT LAKES
REGION. THE FRONT LINGERS OVER OR JUST SOUTH OF SOUTH FL AS HIGH
PRESSURE IN THE SOUTHERN PLAINS AND WESTERN GULF MOVES ACROSS THE
GULF COAST TO THE SE U.S. WHERE IT WEAKENS...ALLOWING MOISTURE FROM
THE FRONT TO CREEP BACK NORTH INTO FL.
THE BEST ODDS OF RAINFALL WILL BE SAT NIGHT WITH LIKELY-CHANCE-
SLIGHT CHANCE SHOWERS AND STORMS...WITH THE HIGHEST POPS IN THE
NORTH. THEN DURING SUN THE GULF COAST LOW MOVES AWAY AND THE FRONT
APPROACHES WITH CHANCE SHOWERS/STORMS. THESE THEN TAPER DOWN TO JUST
SLIGHT CHANCE SHOWERS/STORMS SUN NIGHT-MON NIGHT...GRADUALLY ENDING
FROM NORTHWEST TO SOUTHEAST. MOISTURE INCREASING FROM THE SOUTH WILL
BRING A SLIGHT CHANCE OF SHOWER WED. TEMPERATURES INITIALLY ABOVE
NORMAL SUN WILL DRIP BELOW FOR THE EARLY PART OF THE WEEK THEN WARM
TO NEAR NORMAL BY WED.
&&
.MARINE...
STRONG HIGH PRESSURE BUILDING TO THE NORTH OF THE EASTERN GULF OF
MEXICO WILL TIGHTEN THE PRESSURE GRADIENT ENOUGH TO ALLOW FOR
PERIODS OF ADVISORY LEVEL WINDS TODAY AND TONIGHT. THE GREATEST
COVERAGE OF THESE ELEVATED WINDS WILL OCCUR FROM LATE THIS AFTERNOON
THROUGH TONIGHT...AND THEN FALL BELOW ADVISORY LEVELS FOR ALL ZONES
FRIDAY MORNING. WINDS WILL THEN SHIFT EASTERLY AND EVENTUALLY
SOUTHEASTERLY BY SATURDAY MORNING AHEAD OF THE NEXT COLD FRONT THAT
IS SCHEDULED TO CROSS THE FORECAST WATERS ON SUNDAY.
&&
.AVIATION...
A WEAKENING BOUNDARY EASING SOUTH WILL BRING PREVAILING MVFR VSBY OR
CIGS...THROUGH 12/15Z IN THE NORTH AND 12/18Z IN THE SOUTH. EXPECT
TEMPO IFR MAINLY CIGS AT TERMINALS NORTH OF THE BOUNDARY UNTIL
SHORTLY AFTER SUNRISE. LIGHT NORTHERLY WINDS BECOME NORTH-NORTHEAST
AND INCREASE SOME DURING THE DAY.
&&
.FIRE WEATHER...
DRIER AIR WILL FILTER INTO THE REGION FROM THE NORTH BEHIND A
DEPARTING FRONT DURING TODAY. THE DRIER AIR WILL ALLOW RELATIVE
HUMIDITY LEVELS TO FALL BELOW CRITICAL LEVELS FROM PASCO COUNTY
NORTHWARD THROUGH THE NATURE COAST. PORTIONS OF LEVY AND CITRUS
COUNTIES SHOULD SEE 3-5 HOURS OF THESE CRITICAL RELATIVE HUMIDITY
LEVELS. ELSEWHERE...DRIER AIR WILL FILTER SOUTH...BUT CRITICAL
CONDITIONS ARE NOT ANTICIPATED. DESPITE THE LOW RELATIVE HUMIDITY
LEVELS OVER THE NATURE COAST...WINDS WILL REMAIN BELOW CRITICAL
LEVELS AND CURRENT ERC VALUES ARE BELOW 25. EASTERLY WINDS ON FRIDAY
AND THEN SOUTHEAST WINDS ON SATURDAY WILL INCREASE THE MOISTURE ONCE
AGAIN AND NO FIRE WEATHER CONCERNS ARE ANTICIPATED FOR THE END OF
THE WEEK.
&&
.PRELIMINARY POINT TEMPS/POPS...
TPA 75 52 76 63 / 10 0 0 10
FMY 79 56 80 64 / 10 0 10 10
GIF 74 48 75 59 / 10 10 10 10
SRQ 77 52 78 63 / 10 0 0 10
BKV 72 43 75 57 / 10 10 10 10
SPG 72 55 74 65 / 10 0 0 10
&&
.TBW WATCHES/WARNINGS/ADVISORIES...
FL...NONE.
GULF WATERS...SMALL CRAFT ADVISORY FROM 4 PM THIS AFTERNOON TO
7 AM EST FRIDAY FOR BONITA BEACH TO ENGLEWOOD OUT 20 NM
-BONITA BEACH TO ENGLEWOOD OUT 20 TO 60 NM-ENGLEWOOD TO
TARPON SPRINGS OUT 20 NM.
SMALL CRAFT ADVISORY FROM 7 AM THIS MORNING TO 7 AM EST
FRIDAY FOR ENGLEWOOD TO TARPON SPRINGS OUT 20 TO 60
NM-TARPON SPRINGS TO SUWANNEE RIVER OUT 20 TO 60 NM.
&&
$$
SYNOPSIS/SHORT TERM/MARINE/FIRE WX...MROCZKA
LONG TERM/AVIATION...RUDE
AREA FORECAST DISCUSSION
NWS GOODLAND KS
953 PM MST WED DEC 11 2013
.SHORT TERM...(THIS AFTERNOON THROUGH THURSDAY)
ISSUED AT 1258 PM MST WED DEC 11 2013
LATEST WV IMAGERY AND RAP UPPER LEVEL ANALYSIS SHOW NW FLOW STILL IN
PLACE FROM THE NORTHERN ROCKIES AND ACROSS THE CENTRAL PLAINS...WITH
A SHORTWAVE RIDGE ACROSS THE SW US. AT THE SURFACE 1037MB SURFACE
HIGH PRESSURE ENTERED OVER NORTHEASTERN KS AND SOUTHEASTERN NEBRASKA
WITH A LEE TROUGH JUST EAST OF THE FRONT RANGE IN COLORADO. SOUTH TO
SOUTHWEST GRADIENT BETWEEN THESE FEATURES IS IN PLACE OVER OUR
CWA...WHICH HAS SUPPORTED WAA ACROSS WESTERN LOCATIONS AND ABOVE
FREEZING TEMPERATURES ALONG THE CO/KS STATE LINE.
LOW CLOUDS HAVE PRETTY MUCH CLEARED ACROSS ALL BUT THE FAR
NORTHEAST...AND THESE CLOUDS SHOULD CONTINUE TO DISSIPATE AND MOVE
EAST OUT OF THE AREA. WITH SHORTWAVE RIDGING BUILDING NORTH AND EAST
WE WILL SEE DRY CONDITIONS PERSIST. THE MAIN FORECAST CHALLENGE
THROUGH THE SHORT TERM WILL BE HOW WARM TO MAKE TEMPS. AIR MASS WILL
CONTINUE TO MODERATE WITH SW FLOW SUPPORTING GOOD WAA. MODELS SHOW
H85 TEMPS IN THE 5-7C RANGE...WHICH IF THE GOOD MIXING/WARMING
OBSERVED THE LAST FEW DAYS IS ANY INDICATION WE SHOULD SEE HIGHS AT
LEAST IN THE LOW 50S OVER SNOW FREE AREAS. WITH SW WINDS ADVECTING
THESE WARMER TEMPS TOWARDS SNOW COVERED LOCATIONS IN OUR FAR WEST
AND NORTHEAST WE SHOULD SEE CONTINUED DETERIORATION OF THE SNOW
PACK. I AM NOT AS CONFIDENT ABOUT HIGH TEMP ON THURSDAY OVER
MCCOOK/ATWOOD/OBERLIN...BECAUSE OF THIS SNOW PACK. I WOULD NOT BE
SURPRISED IF AFTER TOMORROW THERE IS NO SIGNIFICANT SNOW PACK LEFT
OVER OUR CWA EVEN IN LOCATIONS THAT SAW 4-5" IN THE NORTHEAST.
.LONG TERM...(THURSDAY NIGHT THROUGH NEXT WEDNESDAY)
ISSUED AT 1209 PM MST WED DEC 11 2013
SHORTWAVE TROUGH WILL MOVE ACROSS THE SOUTHERN PLAINS THURSDAY
NIGHT AND FRIDAY. THE SYSTEM WILL BE TOO FAR SOUTH TO BRING A
CHANCE OF PRECIPITATION TO THE LOCAL AREA...HOWEVER IT WILL TAP
INTO SOME SLIGHTLY COOLER AIR FOR FRIDAY AND SATURDAY...WITH
TEMPERATURES 5 TO 10 DEGREES BELOW NORMAL. THE REMAINDER OF THE
LONG TERM PERIOD WILL SEE VARYING DEGREES OF NORTHWEST FLOW ALOFT.
NO PRECIPITATION IS EXPECTED. TEMPERATURES WILL BE MILD WITH HIGHS
MAINLY IN THE 50S THOUGH COULD REACH THE 60S AND POSSIBLY EVEN 70S
IN A FEW LOCATIONS TUESDAY AND WEDNESDAY WITH DOWNSLOPE WARMING.
HOWEVER...ANOTHER ARCTIC OUTBREAK IS LOOMING FOR THE END OF THE
WEEK WITH BITTERLY COLD AIR MASS UPSTREAM WHICH WILL ARRIVE JUST
BEYOND THIS FORECAST PERIOD.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z THURSDAY NIGHT)
ISSUED AT 953 PM MST WED DEC 11 2013
VFR CONDITIONS WILL CONTINUE. SOUTHWEST WINDS OF 10 KNOTS OR LESS
CAN BE EXPECTED THROUGH THE FORECAST PERIOD.
&&
.GLD WATCHES/WARNINGS/ADVISORIES...
KS...NONE.
CO...NONE.
NE...NONE.
&&
$$
SHORT TERM...DR
LONG TERM...024
AVIATION...BRB
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
1230 AM EST THU DEC 12 2013
.UPDATE...
ISSUED AT 845 PM EST WED DEC 11 2013
LATEST MQT RADAR SHOWS LES BANDS OVER ERN LK SUP HAVE SHIFTED TO THE
N OF GRAND MARAIS. WITH THE LLVL FLOW EXPECTED TO BACK TO MORE WSW
THRU THE NGT...EXPECT THESE BANDS TO STAY N OF ALGER COUNTY. SO CANX
GOING ADVY FOR THAT COUNTY EARLY. THE HEAVIER BANDS ARE STILL
IMPACTING FAR NRN LUCE COUNTY...SO WL KEEP THE WRNG GOING FOR THAT
AREA FOR NOW EVEN THOUGH WIND TRENDS MAY SHIFT THE BANDS N OF THE
COUNTY BEFORE 12Z. MAY CANX THE HEADLINE FOR THIS COUNTY AS WELL IF
PRESENT TRENDS CONTINUE. STLT IMAGERY ALSO SUGS THE BANDS HAVE
SHIFTED OUT OF ALL BUT FAR NRN ONTONAGON COUNTY. CALL TO A SPOTTER
JUST N OF ONTONAGON INDICATES ONLY LGT SN IS FALLING THERE...WITH
JUST AN INCH OF ACCUMULATION THRU THE DAY AND INTO THE EVNG.
CONSIDERING THE SAME BACKING FLOW THAT SHOULD CAUSE THE LES TO IMPACT
AREAS MAINLY N OF ONTONAGON COUNTY...OPTED TO CANX THE LES ADVY FOR
THAT COUNTY AS WELL.
PRES FALL CENTER ASSOCIATED WITH SHRTWV DIGGING SEWD INTO THE UPR
MIDWEST WL PASS TO THE SW OF UPR MI TNGT...SO EXPECT WINDS WL BE
LIGHTER THAN ORIGINALLY FCST. HI CLDS ASSOCIATED WITH THIS
DISTURBANCE WL PASS OVER AT LEAST THE SW HALF OF THE CWA AND
PROBABLY LIMIT THE DIURNAL TEMP FALL AS WELL SO WIND CHILLS WL
PROBABLY END OF NOT BEING AS HARSH AND MORE MARGINAL FOR ADVY...ARND
-25F INSTEAD OF -30 TO -35. OPTED TO KEEP THE GOING WIND CHILL
HEADLINES DESPITE THE MORE MARGINAL NATURE OF THE STILL HAZARDOUS
COLD.
&&
.SHORT TERM...(THIS EVENING THROUGH THURSDAY)
ISSUED AT 407 PM EST WED DEC 11 2013
TWO MAIN ITEMS OF FOCUS IN THE SHORT TERM PERIOD...THE ONGOING LAKE
EFFECT SNOW AND THE CONTINUED COLD WEATHER.
LARGE NORTHERN STREAM UPPER TROUGH COVERS THE UPPER GREAT LAKES
REGION AT THIS TIME...ALLOWING RAP ANALYZED 850MB TEMPS TO BE
AROUND -24C. AT THE SURFACE...A LAKE INDUCED TROUGH REMAINS OVER
THE FAR EASTERN LAKE...WHILE HIGH PRESSURE CENTERED OVER NORTHERN
MISSOURI IS PUSHING A RIDGE OVER NORTHERN MINNESOTA AND NORTHWEST
WISCONSIN. THE COLD AIR MOVING OVER THE RELATIVELY WARM LAKE
SUPERIOR WATERS CONTINUES TO PRODUCE LAKE EFFECT IN THE WEST TO
NORTHWEST WIND LOCATIONS THIS AFTERNOON. THE 925/850MB TROUGH THAT
WAS OVER THE AREA THIS MORNING HAS ALREADY SHIFTED EAST OF THE CWA
AND STARTED TO BACK THE WINDS IN THE LOWER LEVELS OVER THE WESTERN
CWA. THIS CAN BE SEEN IN THE VISIBLE SATELLITE IMAGERY OVER THE
WEST...AS THE BANDS HAVE STARTED TO BECOME WEST-EAST ORIENTATED.
THESE BACKING WINDS ARE ALSO STARTING TO REACH THE CENTRAL LAKE
WHERE THE BANDS ARE NOW MORE IN A WNW DIRECTION AND WINDS AT
STANNARD ROCK HAVE SHIFTED TO THE WEST. EASTERN ALGER AND NORTHERN
LUCE HAVE SEEN THE MOST SNOW TODAY...WITH REPORTS IN THE 2-8 INCH
RANGE.
THE HIGH PRESSURE RIDGE THAT HAS STARTED TO MOVE INTO THE WESTERN
CWA WILL CONTINUE EAST TONIGHT...WHICH WILL CONTINUE TO BACK WINDS
THIS EVENING...TO MORE OF A WESTERLY DIRECTION OR EVEN
WEST-SOUTHWEST OVER THE WESTERN CWA. THESE BACKING WINDS WILL
LIKELY LEAD TO A MORE DOMINATE BAND SETTING UP OVER THE
WEST (WITH THE HELP OF COASTAL CONVERGENCE)...LIKELY IN A SIMILAR
LOCATION TO WHAT WAS SEEN ON MONDAY. UNLIKE MONDAY...INVERSION
HEIGHTS WILL BE FALLING AND MUCH LOWER DUE TO THE APPROACHING
HIGH PRESSURE RIDGE AND INCREASED SUBSIDENCE. THIS COMPRESSES THE
MOISTURE TO AROUND 5KFT FOR CLOUD TOPS...EVEN THOUGH LAKE INDUCED
EQUILIBRIUM LEVELS REACH 8-9KFT. WHILE THIS OCCURS...IT DOES TRY TO
PUSH THE BETTER LAKE FORCING INTO THE TOP OF THE DGZ...WHICH MAY AID
SNOWFALL SIZE/RATIOS TO BE A LITTLE HIGHER THAN SEEN OVER THE LAST
DAY. WITH THE AIDED CONVERGENCE DUE TO WINDS BACKING TO THE
SOUTHWEST...WOULD THINK THAT WOULD HELP OFFSET SOME OF THE LARGE
SCALE SUBSIDENCE AND LEAD TO DECENT ACCUMULATING SNOWFALL FOR
NORTHERN HOUGHTON COUNTY AND THE SOUTHERN PART OF KEWEENAW COUNTY
TONIGHT. THERE IS SOME QUESTION ON HOW QUICKLY IT WILL MOVE NORTH
AND WHERE/WHEN IT WILL STALL TONIGHT. LOCAL HIRES WRF-ARW RUNS
(WHICH HAVE PERFORMED WELL WITH LOCATIONS OVER THE LAST 24HRS) ARE
DIFFERING ON HOW FAR NORTH IT WILL GO...ALONG WITH THE 12Z NAM...SO
OPTED TO SHOW IT REACHING STOPPING AROUND THE HOUGHTON-MOHAWK AREA.
THEREFORE...DID EXPAND SNOWFALL AMOUNTS FARTHER NORTH AND ALSO THE
LES ADVISORY. WAS TEMPTED TO BUMP UP TO A WARNING SINCE THERE WERE
REPORTS OUT WEST WITH 1 IN/HR SNOWFALL IN THE COLDER AIR AND LESS
DGZ INFLUENCE...BUT WITH INVERSION HEIGHTS BEING LOWER DECIDED TO
KEEP AMOUNTS AT HIGH END ADVISORY. WILL NEED TO KEEP AN EYE ON
THINGS THIS EVENING...AS THERE IS THE POTENTIAL FOR BORDERLINE
WARNING AMOUNTS WHERE THAT BAND SETS UP. HEADING INTO
THURSDAY...SLIGHTLY WARMER 925-850MB TEMPS DOES PUSH MORE OF THE
CLOUD INTO THE DGZ...WHICH COULD AID SNOWFALL RATIOS EVEN WITH THE
CONTINUED LIMITED CLOUD DEPTH (INVERSION STAYS THE SAME). WINDS LOOK
TO VEER TO MORE OF A WEST-NORTHWEST AS THE TROUGH SLIDES SOUTH
AGAIN...SO WOULD EXPECT LESS CONVERGENCE AFFECTING THE KEWEENAW
PENINSULA AND THE STRONG CONVERGENCE BAND TO SHIFT BACK TO THE
SOUTH. AS FOR THE OTHER ADVISORIES...ENDED GOGEBIC/BARAGA AND SRN
HOUGHTON EARLY AND ALSO TRENDED ONTONAGON TO AN EARLIER END TIME
DUE THE STRONGEST BAND JUST BRUSHING THE FAR NORTHERN PART OF THAT
COUNTY.
OVER THE EAST...THE BACKING WINDS HAVE ALREADY STARTED TO PUSH
THE STRONGER BANDS NORTHEAST AND WOULD EXPECT THAT STEADY PUSH
TO CONTINUE THIS EVENING. THIS STEADY PUSH SHOULD LEAD TO MORE
STEADY/WIDESPREAD ACCUMULATIONS...GENERALLY IN THE 2-5IN RANGE.
TIMING OF THE ADVISORY FOR ALGER AND NRN SCHOOLCRAFT LOOKS GOOD AND
MAY BE ABLE TO END THE LUCE WARNING A COUPLE HOURS EARLY OVERNIGHT.
AFTER THESE BANDS PUSH NORTHEAST...WOULD EXPECT SKIES TO CLEAR OUT.
THE WESTERLY (OR EVEN SLIGHTLY WSW) FLOW WILL CONTINUE INTO TOMORROW
MORNING...BEFORE THE TROUGH DROPS TO THE SOUTH AND WINDS SHIFT BACK
TO THE WEST-NORTHWEST. THIS SHOULD BE ENOUGH TO MOVE THE BANDS BACK
ONSHORE. INVERSION HEIGHTS WILL BE A LOT LOWER THAN SEEN TODAY
(RADAR INDICATED OF 10-11KFT THIS AFTN DECREASING TO 6-7KFT LATE
TONIGHT THROUGH TOMORROW AFTERNOON). EVEN SO...ENHANCED CONVERGENCE
ALONG THE NEXT TROUGH COULD BE ENOUGH TO LEAD TO A QUICK COUPLE OF
INCHES THURSDAY AFTERNOON OVER LUCE COUNTY.
AS FOR THE COLD TEMPERATURES...ONLY MADE MINOR TWEAKS TO LOWS
TONIGHT AND WINDS. LOWS ARE A LITTLE TRICKY WITH THE HIGH
PRESSURE RIDGE TRYING TO SLIDE IN AND THE MODELS SHOWING
WINDS STRUGGLING TO DECOUPLE. BASED OFF INTERIOR LOCATIONS
LAST NIGHT FALLING TO 4-7KTS...THINK THAT SEEMS REASONABLE FOR
TONIGHT AND POTENTIALLY A LITTLE LOWER WITH THE HELP OF THE HIGH
PRESSURE RIDGE MOVING IN. EXPECT MOST LOCATIONS TO BE WELL BELOW
ZERO WITH THE COLDEST VALUES CONTINUING OVER THE INTERIOR WEST AND
CENTRAL (LOWS IN THE TEENS BELOW ZERO). WIND CHILL ADVISORY LOOKS
TO BE IN GOOD SHAPE AFTER THE MINOR ADJUSTMENTS AND WILL LEAVE THAT
AS IS. ONE OTHER ITEM TO NOTE IS A WEAK SHORTWAVE DIVING SOUTHEAST
ON THE BACK SIDE OF THE UPPER TROUGH THAT WILL MOVE THROUGH
NORTHERN MINNESOTA THIS EVENING AND INTO WISCONSIN OVERNIGHT. MAIN
INFLUENCE WILL BE SOME MID-HIGH CLOUDS...BUT INDICATIONS ARE THAT
MOST OF THOSE CLOUDS WILL STAY SOUTHWEST OF THE CWA TONIGHT BUT MAY
STREAM OVER DURING THE DAY TOMORROW. AREAS RIGHT ALONG THE WISCONSIN
BORDER WOULD HAVE THE BEST OPPORTUNITY FOR THESE MID CLOUDS...WHICH
COULD LEAD TO TEMPS WARMING SLIGHTLY TOWARDS DAYBREAK.
.LONG TERM...(THURSDAY NIGHT THROUGH WEDNESDAY)
ISSUED AT 430 PM EST WED DEC 11 2013
MODELS CONTINUE TO SUGGEST AN OVERALL COLD PATTERN THRU THE LONG
TERM PORTION OF THE FCST. HOWEVER...WITH CURRENT DEEP EXPANSIVE
POLAR VORTEX CENTERED AROUND HUDSON BAY WEAKENING AND RETREATING N
LATE THIS WEEK THRU AT LEAST THE MIDDLE OF NEXT WEEK...THE COLD WILL
EASE SOME. A VAST SUPPLY OF COLD AIR WILL REMAIN ACROSS CANADA...SO
ANY SHORTWAVE TRACKING ALONG IN THE RELAXING NW FLOW PATTERN WILL BE
ABLE TO BRING A SURGE OF COLDER AIR INTO THE UPPER LAKES. OVER THE
PAST SEVERAL DAYS...MEDIUM RANGE GUIDANCE HAS BEEN PROGRESSIVELY
SLOWER TO BRING WARMING INTO THE UPPER LAKES FOR THIS REASON. LATER
DOWN THE ROAD NEXT WEEK...THERE ARE SUGGESTIONS OF A TEMPORARY SHIFT
IN THE PATTERN TOWARD A DEEPENING TROF OVER THE WRN CONUS AND
DOWNSTREAM BUILDING RIDGE OVER THE SE CONUS/WRN ATLANTIC. THIS WILL
OFFER THE BEST CHANCE OF A WARMUP THAT WOULD OCCUR AROUND THE MIDDLE
NEXT WEEK. HOW MUCH WARMING OCCURS WILL DEPEND ON THE AMPLITUDE AND
LONGITUDE OF THE TROF/RIDGE PATTERN. WHATEVER HAPPENS...ANY WARMING
WILL ONLY BE BRIEF AS LONGER RANGE GUIDANCE POINTS TOWARD
REINTENSIFYING ARCTIC AIR ACROSS WRN/NRN CANADA DUMPING BACK INTO
THE AREA SOMETIME AROUND THE WEEKEND BEFORE CHRISTMAS OR EARLY
CHRISTMAS WEEK. OUTSIDE OF THE AREAS AFFECTED BY LES...DON`T EXPECT
MUCH MORE THAN SOME -SN AT TIMES DURING THE LONG TERM. POSSIBLE
BRIEF PATTERN CHANGE LATER NEXT WEEK COULD OFFER THE POTENTIAL FOR
SOMETHING MORE SUBSTANTIAL IN TERMS OF PCPN.
BEGINNING THU NIGHT...SHORTWAVE PASSING ACROSS NRN ONTARIO WILL SEND
A SFC TROF S THRU THE UPPER LAKES...CAUSING WINDS TO VEER NW OR N BY
FRI MORNING. AS A RESULT...ONGOING WRLY FLOW LES LATE THU AFTN WILL
SPREAD S...AFFECTING MOST IF NOT ALL OF NRN UPPER MI BY FRI MORNING.
ALTHOUGH THERE IS NOT MUCH IN THE WAY OF DEEP LAYER FORCING...PERIOD
OF DEEPER MOISTURE COMBINED WITH CONVERGENCE ALONG TROF SHOULD YIELD
A SHORT PERIOD OF MDT SNOW AND POSSIBLY BRIEF HVY SNOW AS TROF
SWEEPS S THU NIGHT AND FRI MORNING. BEHIND TROF...INVERSION SETTLES
TO AROUND 5-6KFT FRI. LARGER SCALE LOW-LEVEL FLOW ALSO BECOMES MORE
ANTICYCLONIC FRI. ON THE OTHER HAND...DIMINISHING BOUNDARY LAYER
WINDS MAY ALLOW FOR LOCALIZED CONVERGENCE. IN FACT...NAM INDICATES
WINDS VEERING TO ESE OFF ERN UPPER MI DURING THE DAY FRI...
RESULTING IN A ZONE OF ENHANCED CONVERGENCE EXTENDING ACROSS FAR SE
LAKE SUPERIOR TO THE MARQUETTE AREA. WILL BE SOMETHING TO MONITOR.
OTHERWISE...DGZ WILL BEGIN TO BECOME BETTER LOCATED WITHIN THE
CONVECTIVE LAYER AND UPWARD MOTION ZONE...LEADING TO HIGHER SNOW TO
WATER RATIOS. SO...SHOULD BE ABLE TO FLUFF UP SOME DECENT SNOW
ACCUMULATIONS FRI WHERE LES IS MOST PERISTENT (NCNTRL UPPER MI). OUT
W DURING THE DAY...WINDS MAY END UP VEERING ENOUGH TO PUSH MOST OF
THE LES OFFSHORE OF WRN UPPER MI...EXCEPT FOR THE KEWEENAW.
WINDS CONTINUE VEERING TO THE E THEN SE FRI NIGHT/SAT MORNING AS SFC
HIGH PRES CENTER PASSES JUST N OF LAKE SUPERIOR. LES THAT WILL BE
OCCURRING MAINLY INTO NCNTRL UPPER MI THU AFTN WILL THEN SLOWLY
SHIFT...CROSSING THE KEWEENAW PENINSULA FOR A TIME LATER FRI
NIGHT/SAT MORNING. DGZ WILL STILL BE WELL CENTERED IN THE CONVECTIVE
LAYER...SO A FEW INCHES OF FLUFFY SNOW ARE POSSIBLE. IF WINDS VEER
ENOUGH OVER NRN LAKE MI...SOME LIGHT LES MAY AFFECT PORTIONS OF
MENOMINEE COUNTY.
ATTENTION THEN TURNS TO NEXT CLIPPER SHORTWAVE DROPPING THRU THE
UPPER GREAT LAKES SAT NIGHT/SUN. -SN ASSOCIATED WITH FEATURE SHOULD
SPREAD INTO THE AREA SAT AFTN/EVENING...AND IT LOOKS LIKE THERE WILL
BE A QUICK PERIOD OF LAKE ENHANCEMENT OFF LAKE MI IN SOUTHERLY
FLOW...LEADING TO A POTENTIAL ADVY EVENT. A VERY BRIEF SHOT OF
ARCTIC AIR FOLLOWING SYSTEM WILL PROBABLY RESULT IN A SHORT DURATION
BOUT OF MDT TO POSSIBLY HVY LAKE ENHANCED SNOW FOR NORTHWEST AND
NORTHEAST UPPER MI LATE SAT NIGHT/EARLY SUNDAY AS WIND SHIFTS NW. AS
WINDS VEER AROUND TO THE N OR NE WITH SFC HIGH PRES PASSING ACROSS
NRN ONTARIO...LIGHTER LES WILL AGAIN SHIFT TO AFFECT MORE OF NRN
UPPER MI SUN AFTN/EVENING.
FCST IS MUCH MORE UNCERTAIN HEADING INTO MON/TUE AS MEDIUM RANGE
MODELS ARE HAVING TROUBLE WITH SEVERAL SHORTWAVES IN THE WNW FLOW.
GIVEN THE UNCERTAINTY FROM TODAYS MODEL RUNS AND PREVIOUS RUNS...A
SIMPLE CONSENSUS WILL BE UTILIZED MON/TUE. DEPENDING ON
STRENGTH/TRACK OF THE WAVES...THERE MAY BE A COUPLE OF PERIODS OF
WIDESPREAD -SN AS WELL AS LAKE ENHANCEMENT DEPENDING ON WIND
DIRECTION.
HIGH UNCERTAINTY CONTINUES WED AS ECMWF SHOWS THE POSSIBLE MID WEEK
WARMUP ALLUDED TO EARLIER...WHILE THE GFS DUMPS ARCTIC AIR BACK INTO
THE AREA. AT 00Z THU...850MB TEMPS RANGE FROM ROUGHLY AROUND -2C
WITH THE ECWMF TO -20C WITH THE GFS.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z THURSDAY NIGHT)
ISSUED AT 1228 AM EST THU DEC 12 2013
CMX...AS THE LLVL FLOW BACKS TOWARD THE SW EARLY THIS MRNG WITH
PASSAGE OF SFC HI PRES TO THE S...EXPECT THE HEAVIER SHSN TO SHIFT
TO THE N OF THIS LOCATION. SO TREND TOWARD MVFR CONDITIONS STILL
SEEMS ON TRACK. BUT THERE IS SOME UNCERTAINTY ON HOW FAR N THE
HEAVIER BANDS WL SHIFT...SO MAINTAINED A MENTION OF SOME OCNL IFR
VSBYS FOR MOST OF THE FIRST 6 HRS OF THE FCST. AS THE WINDS VEER
AGAIN MORE TO THE WNW AND TURN GUSTY LATER THIS MRNG...MORE
SHSN/BLSN WL RETURN ALONG WITH IFR TO PERHAPS LIFR CONDITIONS THRU
THIS EVNG.
FOR KSAW/KIWD...A WSW LLVL FLOW OF DRY UNMODIFIED ARCTIC AIR WL
RESULT IN VFR CONDITIONS THRU SUNRISE AT THESE 2 LOCATIONS. AS THE
FLOW VEERS MORE TO THE WNW LATER THIS MRNG...SOME LOWER MVFR CIGS WL
LIKELY RETURN TO IWD. BUT THE DOWNSLOPE NATURE OF THIS FLOW INTO SAW
SHOULD RESULT IN MORE PERSISTENT VFR CONDITIONS THERE.
&&
.MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 407 PM EST WED DEC 11 2013
WEST TO NORTHWEST WINDS OF 20-30KTS WILL WEAKEN SLIGHTLY TONIGHT AS
A HIGH PRESSURE RIDGE BRUSHES THE AREA. A WEAK TROUGH MOVING ACROSS
THE AREA ON THURSDAY WILL SHIFT WINDS TO MORE OF A NORTHWESTERLY
DIRECTION THURSDAY AFTERNOON AND TO THE NORTH THURSDAY NIGHT AS
ANOTHER HIGH PRESSURE RIDGE (THIS TIME FROM CENTRAL CANADA) NOSES
INTO WESTERN LAKE SUPERIOR. THIS RIDGE IS EXPECTED TO WEAKEN THE
WINDS BELOW 20KTS. DEPENDING ON THE STRENGTH OF A LOW MOVING ACROSS
LAKE SUPERIOR ON SATURDAY NIGHT AND SUNDAY AND THE STRENGTH OF THE
LOW MOVING UP THE EAST COAST...COULD SEE A INCREASE IN
NORTHWESTERLY WINDS ON SUNDAY TO 25-30KTS. THIS WILL BE SHORT LIVED
AS ANOTHER HIGH SLIDES INTO THE AREA FOR THE BEGINNING OF THE
UPCOMING WORK WEEK.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
WIND CHILL ADVISORY UNTIL NOON EST /11 AM CST/ TODAY FOR MIZ002-
004-005-009>013-084.
LAKE EFFECT SNOW ADVISORY UNTIL 9 AM EST THIS MORNING FOR MIZ001-
003.
LAKE SUPERIOR...
HEAVY FREEZING SPRAY WARNING UNTIL 6 AM EST /5 AM CST/ EARLY
THIS MORNING FOR LSZ162-240>245-248>251-266.
HEAVY FREEZING SPRAY WARNING UNTIL 3 PM EST THIS AFTERNOON FOR
LSZ263>265.
LAKE MICHIGAN...
NONE.
&&
$$
UPDATE...KC
SHORT TERM...SRF
LONG TERM...ROLFSON
AVIATION...KC
MARINE...SRF
AREA FORECAST DISCUSSION
NWS ALBUQUERQUE NM
303 AM MST THU DEC 12 2013
.DISCUSSION...
WITH THE EXCEPTION OF A BRIEF BOUT OF RAIN/SNOW TODAY/TONIGHT ACROSS
CENTRAL AND WESTERN NM THE OVERALL PATTERN WILL REMAIN RELATIVELY
TRANQUIL THRU THE NEXT 7 DAYS. CURRENTLY A DEEP FETCH OF SUBTROPICAL
MOISTURE SURGING NE OUT OF THE EQUATORIAL PACIFIC WILL SLIDE OVER
SOUTHERN NM AHEAD OF A WEAK UPPER LOW OVER SOCA. THE LATEST HRRR
AND RUC SOLUTIONS SLOW DOWN TIMING OF PRECIP FOR TODAY SO LOWERED
POPS SUBSTANTIALLY THIS MORNING. THE WPC PROBABILISTIC QPF (PQPF)
INDICATES THE BEST SHOT FOR MEASURABLE IN THE SE WILL BE NOON TO
EARLY EVENING. 700MB WARM ADVECTION WITH THIS FETCH WILL RAISE
SNOW LEVELS TO ABOVE 9000 FT. TEMPS EXPECTED TO WARM ABOVE FREEZING
BY THE TIME PRECIP ARRIVES OVER THE AREA THUS SNOW ACCUMS WILL BE
ABOVE RUIDOSO.
MADE SOME NOTABLE CHANGES TO POP DISTRIBUTION FOR CENTRAL/WESTERN
NM LATE TODAY AND TONIGHT. TRENDED TOWARD SREF/GEFS AND WPC PQPF...
WHICH FOCUSES GREATEST CHANCES ALONG THE CONT DVD TONIGHT THEN THE
CENTRAL MT CHAIN/ABQ METRO AREA EARLY FRIDAY. COLD ADVECTION WITH
THE UPPER COLD CORE WILL ALLOW FOR RAIN TO SNOW...HOWEVER QPF IS
LIGHT...SO EXPECT HIGHEST SNOW AMOUNTS OVER HIGHEST TERRAIN. WILL
ISSUE SPS AGAIN SINCE CONFIDENCE ON TIMING/LOCATION OF COLD AIR
AND PRECIP IS TOO LOW FOR ANY ADVISORIES. ACCUMS LOOK MARGINAL TOO
EVEN IF BEST PRECIP COINCIDES WITH COLD AIR AND INSTABILITY.
AFTER THIS QUICK HIT OF RAIN/SNOW COLDER TEMPS WILL AGAIN SLIDE OVER
THE STATE THIS WEEKEND WITH A SERIES OF WEAK WAVES IN NW FLOW.
OTHERWISE IT WILL REMAIN QUIET THRU NEXT WEEK AS TEMPS MODERATE BACK
NEAR TO SLIGHTLY ABV NORMAL. PERIODIC GUSTY BREEZES IN NW FLOW ARE
LIKELY ALONG WIND PRONE AREAS EAST OF THE CENTRAL MT CHAIN.
GUYER
&&
.FIRE WEATHER...
POOR VENTILATION IS EXPECTED AREAWIDE TODAY AS A LOW PRESSURE SYSTEM
THAT HAS BEEN STALLED OFF THE UPPER BAJA COAST BEGINS TO SHIFT
NORTHEASTWARD TOWARD NM. THE BULK OF THE MOISTURE WITH THE SYSTEM
WILL BE ASSOCIATED WITH THE SUBTROPICAL JET...WHICH WILL SHIFT
EASTWARD ACROSS SOUTHERN NM TODAY. MODELS AND OUR FORECAST GRIDS
HAVE SLOWED THE ARRIVAL OF THIS MOISTURE...WITH RAIN AND VERY HIGH
MOUNTAIN SNOWS FAVORING LOCATIONS ALONG AND SOUTH OF HIGHWAY 60 THIS
AFTERNOON. INSTABILITY LOOKS SUFFICIENT FOR A FEW THUNDERSTORMS TO
DEVELOP OVER THE SW MOUNTAINS THIS AFTERNOON...TOO. THE UPPER LEVEL
LOW AND A PACIFIC COLD FRONT ARE THEN PROGGED TO BRING MODEST
MOISTURE AND COLDER TEMPERATURES TO WESTERN AREAS...AND TO A LESSER
EXTENT CENTRAL AND SOUTHERN AREAS...TONIGHT. THE BAJA SYSTEM WILL
EXIT EASTWARD DURING THE AFTERNOON FRIDAY...BUT A SECONDARY UPPER
LOW RIGHT ON ITS HEELS WILL CROSS THE AREA FROM THE NORTHWEST...
KEEPING SHOWERS IN THE FORECAST FOR CENTRAL AND WESTERN AREAS FRIDAY
AND FRIDAY NIGHT. BY LATE FRIDAY...A FEW INCHES OF SNOW ACCUMULATION
WILL BE POSSIBLE IN THE WESTERN MOUNTAINS...WITH LIGHTER AMOUNTS
ACROSS THE REMAINDER OF THE HIGH TERRAIN. FROM THURSDAY THROUGH
FRIDAY NIGHT...LIQUID AND LIQUID EQUIVALENT PRECIPITATION SHOULD
TOTAL AROUND A QUARTER INCH ACROSS SOUTHERN PARTS OF THE FIRE
WEATHER FORECAST AREA...WITH A TENTH OF AN INCH POSSIBLE IN
LOCATIONS AS FAR NORTH AS THE CHUSKA MOUNTAINS AND ALBUQUERQUE. A
FEW HUNDREDTHS OF AN INCH WILL BE POSSIBLE FROM FARMINGTON TO SANTA
FE AND PORTALES.
IN THE WAKE OF THE PACIFIC COLD FRONT...W AND NW WINDS WILL PICK UP
FRIDAY AS A SPEED MAXIMUM IN THE POLAR JET ROUNDS THE BASE OF THE
SECONDARY UPPER TROUGH AND CROSSES SOUTHERN NM. MEANWHILE...A
SURFACE LOW WILL SHIFT SOUTHEASTWARD FROM SE CO OVER THE TX
PANHANDLE KEEPING THE SURFACE PRESSURE GRADIENT TIGHT ACROSS THE
PLAINS. THE STRONGEST NW WINDS SHOULD BE FOUND ALONG AND SOUTH OF
I-40...WITH GUSTS FROM 40 TO PERHAPS 50 MPH EAST OF THE
SANDIA/MANZANO AND GALLINAS MOUNTAINS TO THE PECOS RIVER. BREEZY
CONDITIONS WILL EXTEND EAST OF THERE TO THE TX BORDER.
FORTUNATELY...HUMIDITIES WILL REMAIN ABOVE CRITICAL THRESHOLDS.
BECAUSE OF THE STRONGER WINDS...THERE WILL BE SOME VENTILATION
IMPROVEMENT FRIDAY ALONG AND SOUTH OF I-40...WITH POOR VENTILATION
LINGERING ACROSS MUCH OF THE NORTH.
ONE LAST WEAK AND DRY UPPER TROUGH WILL DIVE SOUTHEASTWARD ACROSS
THE FORECAST AREA SATURDAY...PROMPTLY BEHIND FRIDAYS SECONDARY
SYSTEM. THIS THIRD TROUGH WILL KEEP COLD AIR ADVECTION IN PLACE FOR
ONE LAST DAY. HIGH TEMPERATURES ARE EXPECTED TO BOTTOM OUT SATURDAY
AROUND 3 TO 10 DEGREES BELOW NORMAL. VENTILATION WILL BE POOR
AREAWIDE...EXCEPT FOR SOME IMPROVEMENT ACROSS THE FAR EASTERN PLAINS
DUE TO GUSTY NORTH WINDS LINGERING BEHIND A BACK DOOR COLD FRONT
THAT WILL SINK SOUTHWARD THROUGH THE PLAINS FRIDAY NIGHT.
DRY NW FLOW ALOFT WILL PERSIST THROUGH THE MIDDLE OF THE COMING
WEEK. WEATHER SYSTEMS WILL PASS FAR ENOUGH NORTH TO KEEP
PRECIPITATION OUT OF THE FORECAST FOR NORTHERN AND CENTRAL NM. A
WARMING TREND WILL DEVELOP SUNDAY THROUGH TUESDAY WITH HIGH
TEMPERATURES REACHING ABOVE NORMAL IN MOST LOCATIONS AS EARLY AS
MONDAY. A BACK DOOR COLD FRONT SHOULD THEN DROP SOUTHWARD THROUGH
THE PLAINS TUESDAY NIGHT COOLING TEMPERATURES ACROSS THE EAST FOR
WEDNESDAY. OTHERWISE...VENTILATION WILL GENERALLY BE POOR...EXCEPT
FOR PERIODS OF IMPROVEMENT ACROSS THE EAST CENTRAL PLAINS.
44
&&
.AVIATION...
06Z TAF CYCLE
WEATHER SYSTEM OVER NORTHERN BAJA CALIFORNIA SHIFTING TO CENTRAL
ARIZONA OVER THE NEXT 24 HRS. CLOUD COVER BUILDING DECK AOA
BKN/OVC050 INTO SOUTHERN AND WESTERN NM FROM 15Z ONWARD THU
MORNING...WITH CLOUD DECK REACHING EAST TO THE RIO GRANDE AND
NORTH ACROSS INTERSTATE 40 FROM 18Z ONWARD. LOWERING CIGS AND RAIN
AND SNOW SHOWERS WILL PRODUCE EXCURSIONS TO MVFR AND IFR AS CLOUD
COVER BUILDS IN. SCT015/SCT025 GROUPS IN TAFS SERVING AS PLACE
HOLDERS FOR MVFR/IFR CIGS AT GUP...ABQ...AEG...SAF...TCC...AND ROW
THU AFTERNOON AND EVE. LOWERING CIG WILL PRODUCE MT OBSCURATION
FOR THE CONTINENTAL DIVIDE AND CENTRAL MOUNTAIN CHAIN FROM 21Z
ONWARD...WITH CONDITIONS CONTG BEYOND 06Z THU EVENING.
SHY
&&
.PRELIMINARY POINT TEMPS/POPS...
FARMINGTON...................... 38 19 38 16 / 5 30 5 0
DULCE........................... 40 11 36 7 / 5 20 10 5
CUBA............................ 42 17 39 12 / 5 30 30 10
GALLUP.......................... 43 21 41 12 / 10 40 20 5
EL MORRO........................ 43 20 39 13 / 20 50 20 5
GRANTS.......................... 43 23 43 15 / 10 40 20 5
QUEMADO......................... 48 25 44 18 / 20 50 20 5
GLENWOOD........................ 51 32 54 22 / 40 40 10 0
CHAMA........................... 38 8 34 9 / 5 20 10 10
LOS ALAMOS...................... 39 23 40 16 / 5 20 30 10
PECOS........................... 43 25 41 17 / 5 20 20 10
CERRO/QUESTA.................... 37 10 37 6 / 5 10 20 10
RED RIVER....................... 39 14 33 8 / 5 10 20 10
ANGEL FIRE...................... 42 10 38 8 / 5 10 20 10
TAOS............................ 40 14 39 9 / 5 10 20 5
MORA............................ 49 22 43 14 / 5 10 20 5
ESPANOLA........................ 43 21 45 16 / 0 10 20 5
SANTA FE........................ 37 24 40 16 / 5 20 30 5
SANTA FE AIRPORT................ 40 24 42 16 / 5 20 30 5
ALBUQUERQUE FOOTHILLS........... 39 27 44 23 / 10 30 40 5
ALBUQUERQUE HEIGHTS............. 42 31 47 24 / 10 20 30 5
ALBUQUERQUE VALLEY.............. 44 27 49 21 / 10 20 30 5
ALBUQUERQUE WEST MESA........... 45 27 48 22 / 10 20 30 5
LOS LUNAS....................... 44 29 50 20 / 10 20 30 5
RIO RANCHO...................... 43 30 47 22 / 10 20 30 5
SOCORRO......................... 48 31 55 24 / 20 20 20 5
SANDIA PARK/CEDAR CREST......... 36 25 42 16 / 10 30 40 10
TIJERAS......................... 38 25 43 20 / 10 20 40 5
MORIARTY/ESTANCIA............... 38 23 43 11 / 10 20 30 10
CLINES CORNERS.................. 37 27 40 16 / 10 20 20 10
GRAN QUIVIRA.................... 43 29 45 21 / 30 30 30 10
CARRIZOZO....................... 47 29 49 24 / 40 30 30 5
RUIDOSO......................... 44 32 48 22 / 60 30 20 5
CAPULIN......................... 46 21 44 14 / 5 5 5 5
RATON........................... 51 25 50 15 / 5 5 5 5
SPRINGER........................ 49 24 51 14 / 0 5 5 5
LAS VEGAS....................... 49 27 46 14 / 5 10 10 5
CLAYTON......................... 53 28 51 20 / 0 5 5 0
ROY............................. 47 26 49 18 / 0 5 5 5
CONCHAS......................... 54 30 56 24 / 0 0 5 0
SANTA ROSA...................... 53 32 54 23 / 10 5 5 0
TUCUMCARI....................... 51 31 56 22 / 5 5 5 0
CLOVIS.......................... 44 27 56 21 / 20 10 5 0
PORTALES........................ 44 30 56 22 / 20 10 5 0
FORT SUMNER..................... 46 30 57 24 / 20 10 5 0
ROSWELL......................... 46 31 63 27 / 50 30 5 0
PICACHO......................... 45 31 57 26 / 60 30 10 5
ELK............................. 47 31 54 25 / 60 30 10 5
&&
.ABQ WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS BINGHAMTON NY
210 AM EST THU DEC 12 2013
.SYNOPSIS...
LAKE EFFECT SNOW WILL CONTINUE EAST AND SOUTHEAST OF LAKES ONTARIO
AND ERIE...OCCASIONALLY BRINGING SNOW SQUALLS TO THE REGION THROUGH
FRIDAY. A VERY COLD AIR MASS WILL KEEP TEMPERATURES BELOW NORMAL
THE REST OF THIS WEEK. A STORM SYSTEM THIS WEEKEND MAY BRING
ACCUMULATING SNOWFALL TO ALL OF NORTHEAST PENNSYLVANIA AND CENTRAL
NEW YORK.
&&
.NEAR TERM /THROUGH TODAY/...
RADAR SHOWS THE LAKE ONTARIO BAND BEGINNING TO MAKES ITS MOVE TO
THE SOUTH AND EAST AT THIS TIME. STILL HAVE SNOW FALLING IN NW
ONEIDA COUNTY SO OPTED TO KEEP WARNING GOING. NEXT UPDATE PROBABLY
WILL BE ABLE TO DROP IT AS SNOWS SHUD BE TO THE SOUTH IN THE NEXT
FEW HOURS. SHORT RANGE MESOSCALE MODELS INDICATE THAT A FAIRLY
STRG SFC HIGH TRIES TO BUILD IN BEHIND THE DEPARTING SHRT WAVE
THAT WAS MOVING INTO NRN NEW ENGLAND AND SERN CANADA AT THIS
TIME. THE EFFECT OF THIS WAS TO VEER THE LL WINDS TO N OR NERLY UP
TO 925 MB IN NC NY WHICH IN EFFECT SHIFTS THE LES BANDS WELL TO
THE W AND WEAKENS THE ACVTY AS VERY DRY BNDRY LAYER AIR MOVES IN.
DWPTS WERE IN THE SINGLE DIGITS SUGGESTING VERY DRY AIR WHICH WUD
CUT DOWN LES POTENTIAL FOR OVRNGT. THE HRRR...LOCAL WRF...WRF-ARW AND
WRF- NMM AND EVEN THE RAP ALL SUGGEST THIS. HOWEVER...THE VWP FROM
KTYX DOES NOT SHOW THIS LL NERLY FLOW AS IT REMAINS NWRLY. THIS
SUGGESTS THAT THESE MESOSCALE MODELS WERE OVERDOING THIS SFC HIGH
WHICH WAS BUILDING TO OUR NORTH. THE NEW 00Z NAM KEEPS A LL NW FLO
DOWN INTO THE LES ADVY AREA ALL NGT AND HENCE...GIVEN THIS NEW MODEL
DATA...RADAR TRENDS AND THE KTYX VWP I THINK OUR LES ADVY FOR NC
NY STILL LOOKS GOOD. TWEAKED AMNTS A TAD BUT GENERALLY 4 TO 7
INCHES WILL FALL IN MUCH OF THIS AREA OVERNIGHT AND THU AM. THE
FLO ACRS THE ENTIRE AREA GOES W-SWRLY THU DURING THE DAY AND THE
LES WILL RAPIDLY SHIFT BACK N THU.
THE LAKE ERIE BAND HAS NOW WORKED OFF OF LAKE ERIE IN THE NW FLO
PATTERN AND WILL ADVECT SOUTHEASTWARD AND FALL APART AS IT MOVES
INTO NE PA AS PER MODEL GUIDC. THERE WILL BE SUBSC AS WELL BEHIND
THE DEPARTING SHRT WAVE AND THE BAND WILL BECOME MOISTURE STARVED
AS IT WORKS AWAY FROM THE LAKE. HENCE NAM AND OTHER MESO MODELS
LOOK ON TRACK WITH THIS BAND FALLING APART IN NE PA AND THE
CATSKILLS NEXT FEW HOURS.
&&
.SHORT TERM /TONIGHT THROUGH FRIDAY NIGHT/...
315 PM UPDATE...
REINVIGORATED LAKE EFFECT SNOW BAND WILL REDEVELOP EAST OF LAKE
ONTARIO THURSDAY NIGHT INTO FRIDAY. SPECIFICS OF EXACTLY WHERE
THAT BAND SETS UP REMAIN TO BE SEEN...BUT THERE IS A GOOD CHANCE
THAT IT WILL INVOLVE NORTHERN ONEIDA COUNTY. DENDRITIC GROWTH
BEGINS TO SLOWLY RISE IN HEIGHT YET ALSO THICKEN WHILE STILL
HAVING OMEGA EXTEND THROUGH IT EVEN INTO FRIDAY MORNING. THIS
ALONG WITH EXPECTED VERY HIGH SNOW TO LIQUID RATIOS COMPELLED ME
TO HOIST ANOTHER LAKE EFFECT SNOW WATCH FOR NORTHERN ONEIDA
COUNTY. EXTREME NORTHERN ONEIDA COUNTY POTENTIAL FOR MORE THAN 6
INCHES OF SNOW LOOKS PRETTY GOOD...AND INDEED IF THE BAND ENDS UP
SITTING THERE INSTEAD OF JUST NORTH...ACCUMULATIONS COULD BE MUCH
MORE. AS WITH ALL LAKE EFFECT...THE HIGHEST AMOUNTS WILL BE
LOCALIZED WITH ONE SPOT GETTING MANY INCHES AND OTHERS JUST A FEW
MILES AWAY SIGNIFICANTLY LESS. MEANWHILE...LAKE ERIE BAND WILL
AGAIN EXTEND SNOW SHOWERS ACROSS MUCH OF CENTRAL NEW YORK WITH
LIGHT FLUFFY ACCUMULATIONS POSSIBLE.
WAVE ASSOCIATED WITH WARM AIR ADVECTION ALOFT...AND SHEARING LOW
LEVEL FLOW...SHOULD DIMINISH LES INTENSITY DURING THE DAY FRIDAY.
HOWEVER...THE WAVE ITSELF COULD YIELD SOME LIGHT SYNOPTIC SNOW
OUTSIDE OF LES AREAS.
&&
.LONG TERM /SATURDAY THROUGH WEDNESDAY/...
205 AM UPDATE...
CONCENTRATED ON THE WEEKEND STORM FOR THIS PACKAGE. OPTED FOR A
GFS/EURO BLEND WHEN DETERMINING PRECIP TYPE, AND SLIGHTLY
TRUNCATED THE SLEET/MIX LINE SOUTHWARD IN FAVOR OF A LITTLE MORE
SNOW.
MODELS CONTINUE TO SHOW SPLIT ENERGY WITH A NEW ENGLAND COAST
CYCLONE HAVING SOME OF ITS POTENCY ROBBED BY THE GREAT LAKES
WAVE/LOW. THE EFFECT IS TO KEEP THE SYSTEM A BIT DISORGANIZED,
THUS DECREASING MAX QPF POTENTIAL. PROVIDED THE SYSTEM REMAINS
COLD, ADVISORY ACCUMS LOOK LIKE A LOCK.
PREV DISCUSSION...
MAIN ISSUE DURING THE LONG TERM PERIOD CONTINUES TO BE POTENTIAL
FOR WIDESPREAD SNOWS AND EVEN THE POSSIBILITY FOR SOME MIXED
PRECIP ACROSS THE LWR WYOMING VLY AND POCONOS BEGINNING SATURDAY
AND LASTING INTO SATURDAY NIGHT/EARLY SUNDAY. DURING THIS
TIMEFRAME...FCST MODELS CONTINUE TO ADVERTISE A NORTHERN STREAM
WAVE DIVING SOUTH AND EAST ACROSS THE WESTERN GREAT LAKES/UPPER
MIDWEST...WHILE ANOTHER SOUTHERN STREAM WAVE EJECTS FROM THE
SOUTHERN PLAINS INTO THE LOWER MISS RVR VLY. AS BOTH UPPER WAVES
DIG...MODELS AGREE THAT A FRONTAL BOUNDARY STALLED TO OUR SOUTH
WILL BEGIN ADVANCING NORTH ONCE AGAIN AS A CONSOLIDATING 850-MB
LOW BEGINS MOVING NORTHEAST FROM THE MID MISS VLY INTO SOUTHERN
ONTARIO PROVINCE BY 00Z SUNDAY. AHEAD OF THIS FEATURE...EXPECT
DEVELOPING WARM AIR ADVECTION SNOWS AS 850-MB FLOW INCREASES TO
NEAR 30 KTS AND ISENTROPIC ASCENT INCREASES ALONG THE 285 AND 290K
THETA SURFACES. FROM THIS VANTAGE POINT...WARM AIR ADVECTION SNOWS
LOOK TO CONTINUE THROUGH A GOOD PART OF THE DAY AS FIRST THE
850-MB LOW CENTER TRACKS NORTH AND EAST OF OUR FCST AREA...AND THE
SOUTHERN STREAM SFC REFLECTION MOVES OFF THE SOUTHEASTERN VIRGINA
COAST BY 00Z SUNDAY. UNDER THIS SCENARIO...MUCH OF THE FCST AREA
WILL REMAIN IN THE NORTHWEST QUADRANT OF THE PRIMARY SFC FEATURE
THUS ENSURING LOW-LEVEL COLD AIR WILL REMAIN IN PLACE THROUGH MUCH
OF THE EVENT. THE ONLY EXCEPTION AS OF RIGHT NOW APPEARS TO BE ACROSS
THE LWR WYOMING VLY AND POCONOS SATURDAY NGT WHERE SOME WARM AIR
MAY TEMPORARILY ADVANCE INTO NORTHEAST PA AS ENERGY FROM THE
NORTHERN STREAM SFC LOW TRANSFERS TO THE MAIN LOW OFF THE
ATLANTIC SEABOARD. SNOWS EXPECTED TO CONTINUE THROUGH MUCH OF THE
OVERNIGHT AS MOISTURE WRAPS IN FROM THE MAIN LOW OFF THE COAST
AND ADDITIONAL FORCING FOR ASCENT BECOMING MORE APPARENT AS PVA
INCREASES IN ADVANCE OF AFOREMENTIONED NORTHERN STREAM WAVE
APPROACHING FROM THE CENTRAL LAKES AND SOUTHERN ONTARIO. AS A
RESULT...CONFIDENCE IS INCREASING THAT SEVERAL INCHES OF SYNOPTIC
SNOW CAN BE EXPECTED ACROSS THE AREA THROUGH THE WEEKEND. FOR
NOW...WILL HIGHLIGHT CONCERNS ON THE HWO PRODUCT UNTIL FCST
DETAILS BECOME MORE CERTAIN PENDING ADDITIONAL MODEL GUIDANCE.
BEYOND THIS...BROAD NORTHWEST FLOW TO RESULT IN REDEVELOPING LAKE
SNOWS EAST AND SOUTHEAST OF BOTH LAKES EARLY INTO NEXT WEEK...WITH
ADDITIONAL SYNOPTIC SNOWS POSSIBLE MONDAY NIGHT/EARLY TUESDAY AS
ELONGATED WARM FRONT ADVANCES NORTH ACROSS THE AREA. TEMPS THROUGH
THE PERIOD LOOK TO HOVER SLIGHTLY BELOW NORMAL AS COOL NORTHWEST
FLOW REMAINS IN PLACE.
&&
.AVIATION /07Z THURSDAY THROUGH MONDAY/...
LAKE BAND HAS SHIFTED WITH A MORE NORTHWESTERLY WIND COMPONENT,
EXITING RME AND ENTERING SYR. THE LAKE SNOW BAND WILL RAPIDLY
WEAKEN BETWEEN 8Z AND 10Z, AS LOW AMPLITUDE WIND FLOW WILL
DIMINISH THE INLAND BAND EXTENT. AS A RESULT, WE EXPECT IFR
CONDITIONS TO PERSIST AT SYR THROUGH THE NEXT 3 TO 4 HOURS, WITH
TEMPO IFR POSSIBLE THROUGH 10Z.
AFTER 10Z THE BAND SHOULD HAVE EXITED THE SYR TERMINAL COMPLETELY.
THE LAKE BAND WILL REFORM DURING THE AFTERNOON. IT APPEARS THE
BAND WILL AFFECT FAR NORTHERN ONEIDA COUNTY AND OSWEGO COUNTY.
HOWEVER THE PERIPHERY MAY BRUSH RME. THE BEST CHANCE FOR MVFR OR
IFR SNOW SHOWERS AT RME WILL BE BETWEEN 16Z AND 20Z.
LAKE ERIE SNOW SHOWERS COULD POTENTIALLY AFFECT THE BGM, ELM, OR
ITH TERMINALS AT ANY POINT THIS AFTERNOON. THESE SHOULD BE BRIEF
ENOUGH TO PRECLUDE INCLUDING IN THE FORECAST. FUTURE SHIFTS CAN
HANDLE ISOLATED LAKE ACTIVITY WITH AMD UPDATES.
OUTLOOK...
FRI...MAINLY VFR...HOWEVER RESTRICTIONS POSSIBLE IN LAKE EFFECT
SNOW AT KRME.
SAT/SUN...RESTRICTIONS LIKELY REGION-WIDE IN SNOW AS STORM SYSTEM
MOVES THROUGH THE AREA.
SUN NGT/MON...RESTRICTIONS POSSIBLE FROM LAKE EFFECT SNOW SHOWERS
ESPECIALLY KSYR-KRME.
&&
.BGM WATCHES/WARNINGS/ADVISORIES...
PA...NONE.
NY...LAKE EFFECT SNOW ADVISORY UNTIL 11 AM EST THIS MORNING FOR
NYZ017-018-036-037-044>046.
LAKE EFFECT SNOW WATCH FROM NOON EST TODAY THROUGH FRIDAY
AFTERNOON FOR NYZ009.
&&
$$
SYNOPSIS...DJN
NEAR TERM...DJN
SHORT TERM...MDP
LONG TERM...CMG/DJP
AVIATION...DJP
AREA FORECAST DISCUSSION
NWS BINGHAMTON NY
1227 AM EST THU DEC 12 2013
.SYNOPSIS...
LAKE EFFECT SNOW WILL CONTINUE EAST AND SOUTHEAST OF LAKES ONTARIO
AND ERIE...OCCASIONALLY BRINGING SNOW SQUALLS TO THE REGION THROUGH
FRIDAY. A VERY COLD AIR MASS WILL KEEP TEMPERATURES BELOW NORMAL
THE REST OF THIS WEEK. A STORM SYSTEM THIS WEEKEND MAY BRING
ACCUMULATING SNOWFALL TO ALL OF NORTHEAST PENNSYLVANIA AND CENTRAL
NEW YORK.
&&
.NEAR TERM /THROUGH TODAY/...
RADAR SHOWS THE LAKE ONTARIO BAND BEGINNING TO MAKES ITS MOVE TO
THE SOUTH AND EAST AT THIS TIME. STILL HAVE SNOW FALLING IN NW
ONEIDA COUNTY SO OPTED TO KEEP WARNING GOING. NEXT UPDATE PROBABLY
WILL BE ABLE TO DROP IT AS SNOWS SHUD BE TO THE SOUTH IN THE NEXT
FEW HOURS. SHORT RANGE MESOSCALE MODELS INDICATE THAT A FAIRLY
STRG SFC HIGH TRIES TO BUILD IN BEHIND THE DEPARTING SHRT WAVE
THAT WAS MOVING INTO NRN NEW ENGLAND AND SERN CANADA AT THIS
TIME. THE EFFECT OF THIS WAS TO VEER THE LL WINDS TO N OR NERLY UP
TO 925 MB IN NC NY WHICH IN EFFECT SHIFTS THE LES BANDS WELL TO
THE W AND WEAKENS THE ACVTY AS VERY DRY BNDRY LAYER AIR MOVES IN.
DWPTS WERE IN THE SINGLE DIGITS SUGGESTING VERY DRY AIR WHICH WUD
CUT DOWN LES POTENTIAL FOR OVRNGT. THE HRRR...LOCAL WRF...WRF-ARW AND
WRF- NMM AND EVEN THE RAP ALL SUGGEST THIS. HOWEVER...THE VWP FROM
KTYX DOES NOT SHOW THIS LL NERLY FLOW AS IT REMAINS NWRLY. THIS
SUGGESTS THAT THESE MESOSCALE MODELS WERE OVERDOING THIS SFC HIGH
WHICH WAS BUILDING TO OUR NORTH. THE NEW 00Z NAM KEEPS A LL NW FLO
DOWN INTO THE LES ADVY AREA ALL NGT AND HENCE...GIVEN THIS NEW MODEL
DATA...RADAR TRENDS AND THE KTYX VWP I THINK OUR LES ADVY FOR NC
NY STILL LOOKS GOOD. TWEAKED AMNTS A TAD BUT GENERALLY 4 TO 7
INCHES WILL FALL IN MUCH OF THIS AREA OVERNIGHT AND THU AM. THE
FLO ACRS THE ENTIRE AREA GOES W-SWRLY THU DURING THE DAY AND THE
LES WILL RAPIDLY SHIFT BACK N THU.
THE LAKE ERIE BAND HAS NOW WORKED OFF OF LAKE ERIE IN THE NW FLO
PATTERN AND WILL ADVECT SOUTHEASTWARD AND FALL APART AS IT MOVES
INTO NE PA AS PER MODEL GUIDC. THERE WILL BE SUBSC AS WELL BEHIND
THE DEPARTING SHRT WAVE AND THE BAND WILL BECOME MOISTURE STARVED
AS IT WORKS AWAY FROM THE LAKE. HENCE NAM AND OTHER MESO MODELS
LOOK ON TRACK WITH THIS BAND FALLING APART IN NE PA AND THE
CATSKILLS NEXT FEW HOURS.
&&
.SHORT TERM /TONIGHT THROUGH FRIDAY NIGHT/...
315 PM UPDATE...
REINVIGORATED LAKE EFFECT SNOW BAND WILL REDEVELOP EAST OF LAKE
ONTARIO THURSDAY NIGHT INTO FRIDAY. SPECIFICS OF EXACTLY WHERE
THAT BAND SETS UP REMAIN TO BE SEEN...BUT THERE IS A GOOD CHANCE
THAT IT WILL INVOLVE NORTHERN ONEIDA COUNTY. DENDRITIC GROWTH
BEGINS TO SLOWLY RISE IN HEIGHT YET ALSO THICKEN WHILE STILL
HAVING OMEGA EXTEND THROUGH IT EVEN INTO FRIDAY MORNING. THIS
ALONG WITH EXPECTED VERY HIGH SNOW TO LIQUID RATIOS COMPELLED ME
TO HOIST ANOTHER LAKE EFFECT SNOW WATCH FOR NORTHERN ONEIDA
COUNTY. EXTREME NORTHERN ONEIDA COUNTY POTENTIAL FOR MORE THAN 6
INCHES OF SNOW LOOKS PRETTY GOOD...AND INDEED IF THE BAND ENDS UP
SITTING THERE INSTEAD OF JUST NORTH...ACCUMULATIONS COULD BE MUCH
MORE. AS WITH ALL LAKE EFFECT...THE HIGHEST AMOUNTS WILL BE
LOCALIZED WITH ONE SPOT GETTING MANY INCHES AND OTHERS JUST A FEW
MILES AWAY SIGNIFICANTLY LESS. MEANWHILE...LAKE ERIE BAND WILL
AGAIN EXTEND SNOW SHOWERS ACROSS MUCH OF CENTRAL NEW YORK WITH
LIGHT FLUFFY ACCUMULATIONS POSSIBLE.
WAVE ASSOCIATED WITH WARM AIR ADVECTION ALOFT...AND SHEARING LOW
LEVEL FLOW...SHOULD DIMINISH LES INTENSITY DURING THE DAY FRIDAY.
HOWEVER...THE WAVE ITSELF COULD YIELD SOME LIGHT SYNOPTIC SNOW
OUTSIDE OF LES AREAS.
&&
.LONG TERM /SATURDAY THROUGH WEDNESDAY/...
MAIN ISSUE DURING THE LONG TERM PERIOD CONTINUES TO BE POTENTIAL
FOR WIDESPREAD SNOWS AND EVEN THE POSSIBILITY FOR SOME MIXED
PRECIP ACROSS THE LWR WYOMING VLY AND POCONOS BEGINNING SATURDAY
AND LASTING INTO SATURDAY NIGHT/EARLY SUNDAY. DURING THIS
TIMEFRAME...FCST MODELS CONTINUE TO ADVERTISE A NORTHERN STREAM
WAVE DIVING SOUTH AND EAST ACROSS THE WESTERN GREAT LAKES/UPPER
MIDWEST...WHILE ANOTHER SOUTHERN STREAM WAVE EJECTS FROM THE
SOUTHERN PLAINS INTO THE LOWER MISS RVR VLY. AS BOTH UPPER WAVES
DIG...MODELS AGREE THAT A FRONTAL BOUNDARY STALLED TO OUR SOUTH
WILL BEGIN ADVANCING NORTH ONCE AGAIN AS A CONSOLIDATING 850-MB
LOW BEGINS MOVING NORTHEAST FROM THE MID MISS VLY INTO SOUTHERN
ONTARIO PROVINCE BY 00Z SUNDAY. AHEAD OF THIS FEATURE...EXPECT
DEVELOPING WARM AIR ADVECTION SNOWS AS 850-MB FLOW INCREASES TO
NEAR 30 KTS AND ISENTROPIC ASCENT INCREASES ALONG THE 285 AND 290K
THETA SURFACES. FROM THIS VANTAGE POINT...WARM AIR ADVECTION SNOWS
LOOK TO CONTINUE THROUGH A GOOD PART OF THE DAY AS FIRST THE
850-MB LOW CENTER TRACKS NORTH AND EAST OF OUR FCST AREA...AND THE
SOUTHERN STREAM SFC REFLECTION MOVES OFF THE SOUTHEASTERN VIRGINA
COAST BY 00Z SUNDAY. UNDER THIS SCENARIO...MUCH OF THE FCST AREA
WILL REMAIN IN THE NORTHWEST QUADRANT OF THE PRIMARY SFC FEATURE
THUS ENSURING LOW-LEVEL COLD AIR WILL REMAIN IN PLACE THROUGH MUCH
OF THE EVENT. THE ONLY EXCEPTION AS OF RIGHT NOW APPEARS TO BE ACROSS
THE LWR WYOMING VLY AND POCONOS SATURDAY NGT WHERE SOME WARM AIR
MAY TEMPORARILY ADVANCE INTO NORTHEAST PA AS ENERGY FROM THE
NORTHERN STREAM SFC LOW TRANSFERS TO THE MAIN LOW OFF THE
ATLANTIC SEABOARD. SNOWS EXPECTED TO CONTINUE THROUGH MUCH OF THE
OVERNIGHT AS MOISTURE WRAPS IN FROM THE MAIN LOW OFF THE COAST
AND ADDITIONAL FORCING FOR ASCENT BECOMING MORE APPARENT AS PVA
INCREASES IN ADVANCE OF AFOREMENTIONED NORTHERN STREAM WAVE
APPROACHING FROM THE CENTRAL LAKES AND SOUTHERN ONTARIO. AS A
RESULT...CONFIDENCE IS INCREASING THAT SEVERAL INCHES OF SYNOPTIC
SNOW CAN BE EXPECTED ACROSS THE AREA THROUGH THE WEEKEND. FOR
NOW...WILL HIGHLIGHT CONCERNS ON THE HWO PRODUCT UNTIL FCST
DETAILS BECOME MORE CERTAIN PENDING ADDITIONAL MODEL GUIDANCE.
BEYOND THIS...BROAD NORTHWEST FLOW TO RESULT IN REDEVELOPING LAKE
SNOWS EAST AND SOUTHEAST OF BOTH LAKES EARLY INTO NEXT WEEK...WITH
ADDITIONAL SYNOPTIC SNOWS POSSIBLE MONDAY NIGHT/EARLY TUESDAY AS
ELONGATED WARM FRONT ADVANCES NORTH ACROSS THE AREA. TEMPS THROUGH
THE PERIOD LOOK TO HOVER SLIGHTLY BELOW NORMAL AS COOL NORTHWEST
FLOW REMAINS IN PLACE.
&&
.AVIATION /05Z THURSDAY THROUGH MONDAY/...
LAKE BAND HAS SHIFTED WITH A MORE NORTHWESTERLY WIND COMPONENT,
EXITING RME AND ENTERING SYR. THE LAKE SNOW BAND WILL RAPIDLY
WEAKEN BETWEEN 8Z AND 10Z, AS LOW AMPLITUDE WIND FLOW WILL
DIMINISH THE INLAND BAND EXTENT. AS A RESULT, WE EXPECT IFR
CONDITIONS TO PERSIST AT SYR THROUGH THE NEXT 3 TO 4 HOURS, WITH
TEMPO IFR POSSIBLE THROUGH 10Z.
AFTER 10Z THE BAND SHOULD HAVE EXITED THE SYR TERMINAL COMPLETELY.
THE LAKE BAND WILL REFORM DURING THE AFTERNOON. IT APPEARS THE
BAND WILL AFFECT FAR NORTHERN ONEIDA COUNTY AND OSWEGO COUNTY.
HOWEVER THE PERIPHERY MAY BRUSH RME. THE BEST CHANCE FOR MVFR OR
IFR SNOW SHOWERS AT RME WILL BE BETWEEN 16Z AND 20Z.
LAKE ERIE SNOW SHOWERS COULD POTENTIALLY AFFECT THE BGM, ELM, OR
ITH TERMINALS AT ANY POINT THIS AFTERNOON. THESE SHOULD BE BRIEF
ENOUGH TO PRECLUDE INCLUDING IN THE FORECAST. FUTURE SHIFTS CAN
HANDLE ISOLATED LAKE ACTIVITY WITH AMD UPDATES.
OUTLOOK...
FRI...MAINLY VFR...HOWEVER RESTRICTIONS POSSIBLE IN LAKE EFFECT
SNOW AT KRME.
SAT/SUN...RESTRICTIONS LIKELY REGION-WIDE IN SNOW AS STORM SYSTEM
MOVES THROUGH THE AREA.
SUN NGT/MON...RESTRICTIONS POSSIBLE FROM LAKE EFFECT SNOW SHOWERS
ESPECIALLY KSYR-KRME.
&&
.BGM WATCHES/WARNINGS/ADVISORIES...
PA...NONE.
NY...LAKE EFFECT SNOW ADVISORY UNTIL 11 AM EST THIS MORNING FOR
NYZ017-018-036-037-044>046.
LAKE EFFECT SNOW WATCH FROM NOON EST TODAY THROUGH FRIDAY
AFTERNOON FOR NYZ009.
LAKE EFFECT SNOW WARNING UNTIL 6 AM EST EARLY THIS MORNING FOR
NYZ009.
&&
$$
SYNOPSIS...DJN
NEAR TERM...DJN
SHORT TERM...MDP
LONG TERM...CMG
AVIATION...DJP
AREA FORECAST DISCUSSION
NWS BISMARCK ND
1238 AM CST THU DEC 12 2013
.UPDATE...
ISSUED AT 1237 AM CST THU DEC 12 2013
UPDATE TO INTRODUCE CHANCE POPS ACROSS NORTHWEST NORTH DAKOTA AS
AN AREA OF LIGHT SNOW CONTINUES TO COME INTO BETTER VIEW ON RADAR
ACROSS NORTHEAST MONTANA. THE 05 UTC RAP PROPAGATES THIS AREA OF
SNOW INTO NORTHWEST NORTH DAKOTA AFTER 08 UTC.
UPDATE ISSUED AT 948 PM CST WED DEC 11 2013
NO MAJOR CHANGES WERE MADE TO THE ONGOING FORECAST. ONLY ADJUSTED
THE HOURLY SENSIBLE WEATHER GRIDS BASED ON CURRENT OBS/TRENDS. THE
UPDATED PRODUCTS HAVE BEEN SENT.
UPDATE ISSUED AT 713 PM CST WED DEC 11 2013
A WARM FRONT HAS MOVED ACROSS THE STATE FASTER THAN PREVIOUSLY
ANTICIPATED. AS A RESULT...UPDATED HOURLY TEMPS BASED ON CURRENT
OBS/TRENDS...AND ADJUSTED THE FORECAST LOWS UP ACROSS AREAS EAST
OF HIGHWAY 83 TONIGHT. THE REMAINING FORECAST ELEMENTS ARE IN GOOD
SHAPE. THE UPDATED PRODUCTS HAVE BEEN SENT.
&&
.SHORT TERM...(THIS EVENING THROUGH THURSDAY)
ISSUED AT 311 PM CST WED DEC 11 2013
WIND CHILLS HAVE FINALLY IMPROVED TO THE POINT THAT THE ADVISORY
CAN BE CANCELLED ACROSS THE NORTH CENTRAL. INCREASING CLOUDS EAST
OF A WARM FRONTAL BOUNDARY IN MONTANA WILL BRING STEADY OR RISING
TEMPERATURES TO THE DEVILS LAKE BASIN INTO THE JAMES RIVER VALLEY.
ALTHOUGH THEIR IS UNCERTAINTY ON THE AMOUNT OF DIURNAL
TREND...THERE IS THE POTENTIAL THE TEMPS WILL FALL OFF THIS
EVENING THEN BECOME STEADY OR SLOWLY RISE OVERNIGHT. OVERNIGHT
LOWS SHOULD BE 15 DEGREES OR MORE HIGHER THAN LAST
NIGHT...ESPECIALLY SOUTHWEST WHERE TEMPERATURES THURSDAY MORNING
WILL BE 35 TO 40 DEGREES WARMER THAN WEDNESDAY MORNING. KEPT A
SLIGHT CHANCE OF SNOW ACROSS THE NORTH CENTRAL INTO THE JAMES
RIVER VALLEY TONIGHT.
.LONG TERM...(THURSDAY NIGHT THROUGH WEDNESDAY)
ISSUED AT 311 PM CST WED DEC 11 2013
THE MAIN FORECAST CHALLENGE IS TIMING SEVERAL LIGHT SNOW EVENTS AND
TIMING OF COLD AND WARM FRONTS MOVING THROUGH THE REGION AS A BATTLE
CONTINUES BETWEEN ARCTIC AIR MOVING SOUTH FROM CANADA VERSUS THE
MILDER PACIFIC AIR TO OUR WEST/SOUTHWEST.
AFTER A RELATIVELY MILD DAY ON THURSDAY...MODEL CONSENSUS DEPICTS
THE ARRIVAL OF A SHORT WAVE IN NORTHWEST FLOW THURSDAY AFTERNOON AND
NIGHT. LIGHT SNOW IS EXPECTED ACROSS NORTHERN NORTH DAKOTA THURSDAY
NIGHT...WITH AN INCH OR 2 OF SNOW EXPECTED IN THE NORTH CENTRAL -
MAINLY FROM CROSBY TO THE TURTLE MOUNTAINS INCLUDING MINOT AND
RUGBY.
LIGHT SNOW IS FORECAST TO SPREAD SOUTHWARD ON FRIDAY AS ARCTIC AIR
SLIDES SOUTHEAST INTO THE RED RIVER VALLEY AND THE WESTERN EDGE OF
THE ARCTIC AIR IS OVER THE SOUTHWESTERN COUNTIES. LOOKING AT HIGHS
FROM AROUND 5 BELOW IN THE TURTLE MOUNTAINS TO AROUND 20 ABOVE ZERO
IN THE FAR SOUTHWEST. ALSO LOOKING AT SNOWFALL AMOUNTS DAYTIME
FRIDAY FROM 1/2 AN INCH TO 1 INCH OVER NORTHWESTERN AND CENTRAL
NORTH DAKOTA WITH LITTLE ACCUMULATION IN THE SOUTHWEST.
FRIDAY NIGHT THE ARCTIC HIGH CONTINUES SOUTHEASTWARD OUT OF NORTH
DAKOTA WITH ANOTHER ARCTIC HIGH OVER THE CANADIAN FRONT RANGE POISED
TO MOVE SOUTH. LOWS IN SOUTHWESTERN NORTH DAKOTA SHOULD BE IN THE
SINGLE DIGITS ABOVE ZERO...BUT FARTHER NORTH AND EAST EXPECT LOWS
FROM 5 TO 10 BELOW MOST AREAS. STILL SOME LIGHT SNOW AMOUNTS
EXPECTED - MAINLY NORTH.
THUS THURSDAY NIGHT THROUGH FRIDAY NIGHT SNOW AMOUNTS SHOULD BE
GENERALLY IN THE 1-3 INCH RANGE ACROSS NORTHERN NORTH DAKOTA...WITH
AROUND 1/2 INCH OF SNOW ACROSS THE SOUTH CENTRAL...AND LITTLE
ACCUMULATION IN THE SOUTHWEST.
FOR THE WEEKEND INTO NEXT WEEK:
ON SATURDAY NIGHT ANOTHER ARCTIC COLD FRONT MOVES THROUGH THE
FORECAST AREA...THEN PUSHES EAST OF THE REGION ON SUNDAY.
A WARM-UP PERIOD IS THEN FORECAST TO ENSUE SUNDAY THROUGH
TUESDAY...BUT YET ANOTHER ARCTIC OUTBREAK IS IN THE OFFING FOR
WEDNESDAY THROUGH THE WEEK.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z THURSDAY NIGHT)
ISSUED AT 1237 AM CST THU DEC 12 2013
IFR CONDITIONS IN LIGHT SNOW IS POSSIBLE AT KISN BETWEEN 08 AND 11
UTC THURSDAY MORNING. ANOTHER WEAK SYSTEM WILL IMPACT WESTERN AND
CENTRAL NORTH DAKOTA THURSDAY AFTERNOON AND INTO THE NIGHT. MVFR
CONDITIONS IN STRATUS ARE EXPECTED AT KISN/KJMS/KBIS...WITH IFR
CONDITIONS IN SNOW AT KMOT.
&&
.BIS WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...AYD
SHORT TERM...WAA
LONG TERM...WAA/JV
AVIATION...AYD
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
329 AM CST THU DEC 12 2013
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 329 AM CST THU DEC 12 2013
CURRENTLY AS OF 09Z...WATER VAPOR LOOP AND RAP 500MB HEIGHT ANALYSIS
SHOWED RIDGING OVER THE WESTERN U.S. INTO SOUTHWEST CANADA...AND
TROUGHING OVER EASTERN CANADA INTO THE GREAT LAKES. IN THE NORTHWEST
FLOW BETWEEN THE RIDGE AND TROUGH...A SHORTWAVE WAS NOTED OVER
NORTHWEST WISCONSIN. DPVA FORCING FROM THE SHORTWAVE COMBINED WITH
ISENTROPIC LIFT ON THE 275-280K SURFACES AS SUGGESTED BY THE RAP HAS
SPREAD LIGHT SNOW ACROSS THE NORTHEAST HALF OF THE FORECAST AREA. IN
ADDITION...THE CLOUDS AND A WARM ADVECTION SOUTHWEST WIND IN THE LOW
LEVELS HAS CAUSED TEMPERATURES TO CLIMB OVERNIGHT. THE BREEZE...
HOWEVER...HAS HELD WIND CHILLS DOWN TO 10 TO 20 BELOW ZERO SOUTHWEST
OF I-94 TO 20 TO 25 BELOW ZERO TO THE NORTH. REGARDING THE WARM
ADVECTION HIGHER ABOVE THE SURFACE...FROM 00Z SOUNDINGS...850MB
TEMPS WERE AROUND -20C OVER THE FORECAST AREA COMPARED TO -7C AT
BIS AND AROUND -10C AT ABR AND OAX. FARTHER UPSTREAM...PLENTY OF
HIGH CLOUDS REFLECTING PACIFIC MOISTURE WERE STREAMING INTO NORTH
DAKOTA IN THE WAKE OF THE SHORTWAVE.
FIRST...WITH RESPECT TO THE WIND CHILL HAZARDS...WILL LET THEM
EXPIRE AT 12Z. ALTHOUGH WIND CHILLS ARE IMPROVING...THERE IS ONLY A
FEW HOURS LEFT TO THE ADVISORY...AND THEY ARE STILL CHILL AS
MENTIONED ABOVE.
ONGOING SNOW EARLY THIS MORNING REMAINS ON TRACK TO QUICKLY EXIT THE
FORECAST AREA...LIKELY BY 7 AM...AS THE SHORTWAVE HEADS OFF TO LAKE
MICHIGAN BY 12Z. OTHERWISE...THE REST OF THE SHORT TERM GENERALLY
LOOKS QUIET PRECIPITATION-WISE AS THE UPPER LEVEL FLOW BECOMES MORE
ZONAL OVER THE NORTHERN U.S.. THE 12.00Z GFS/CANADIAN AND 12.03Z
SREF ALL SHOW SOME LIGHT SNOW OR FLURRIES FALLING LATE THIS
AFTERNOON INTO EARLY THIS EVENING FROM TAYLOR COUNTY NORTHWARD. THIS
LIGHT PRECIPITATION IS ASSOCIATED WITH WEAK BUT MAINTAINED
ISENTROPIC LIFT AND MID-LEVEL FRONTOGENESIS. DECIDED TO ADD SOME LOW
CHANCES ON THE ORDER OF 20 PERCENT TO TAYLOR COUNTY. DESPITE MAINLY
DRY WEATHER FOR THE NEXT 24 HOURS...WE SHOULD SEE QUITE A BIT OF
CLOUD COVER...ESPECIALLY OVER THE NORTH HALF OF THE FORECAST AREA.
THESE CLOUDS OF THE MID/HIGH LEVEL VARIETY REFLECT BOTH THE PACIFIC
MOISTURE FLOWING IN BEHIND THE CURRENT SHORTWAVE AS WELL AS THE
GENERAL WARM ADVECTION PATTERN. ADDITIONALLY...LATE TONIGHT...THE
FORECAST AREA LIES IN THE RIGHT ENTRANCE REGION OF AN UPPER JET
STREAK OVER THE UPPER GREAT LAKES...FAVORING CLOUDS.
WARMER TEMPERATURES ARE ON TRACK TODAY AS SOUTHWEST WINDS BRING UP
WARMER AIR OUT OF NEBRASKA. THE 24 HOUR CHANGE AT 850MB IS FAIRLY
IMPRESSIVE...FROM THE -20C OBSERVED BACK AT 00Z YESTERDAY EVENING TO
-2C TO -10C FOR THIS EVENING. WE CERTAINLY WILL NOT MIX TO THESE
VALUES GIVEN TIME OF YEAR...CLOUDS AND SNOW COVER...BUT DEFINITELY
WARMER NONETHELESS. COLDEST READINGS WILL REMAIN IN THE CHIMNEY
AREA. AS THE UPPER FLOW TURNS ZONAL TONIGHT...A COLD FRONT CURRENTLY
OVER SOUTHERN SASKATCHEWAN IS PROGGED TO SLIDE SOUTH THROUGH THE
FORECAST AREA. THE COLD AIR IS SHALLOW BEHIND THIS FRONT AS MUCH OF
THE TEMPERATURE FALL TAKES PLACE AT 925MB AND BELOW. 925MB TEMPS
FALL 6C ON A NORTH TO NORTHEAST WIND...SO WE SHOULD SEE A DECENT
TEMPERATURE DROP TONIGHT DESPITE CLOUDS IN PLACE.
.LONG TERM...(FRIDAY THROUGH WEDNESDAY)
ISSUED AT 329 AM CST THU DEC 12 2013
FOR FRIDAY THROUGH SATURDAY...ATTENTION TURNS TO AN UPPER LOW
CURRENTLY SITTING NEAR FAR SOUTHERN CALIFORNIA. 12.00Z MODELS
REMAIN CONSISTENT ON TRACKING THIS FEATURE INTO THE CENTRAL
PLAINS ON FRIDAY...THEN UP THROUGH THE OHIO VALLEY FRIDAY NIGHT
AND SATURDAY. THIS TRACK WOULD KEEP THE BULK OF THE SYSTEMS
PRECIPITATION... INCLUDING THE DEFORMATION SHIELD...SOUTHEAST OF
THE FORECAST AREA. 12.00Z ECMWF SHOWS A COMPLETELY DRY FORECAST
FOR THE AREA. HOWEVER...THE 12.00Z GFS/CANADIAN/NAM SUGGEST
POTENTIAL FOR LIGHT SNOW THROUGH THIS ENTIRE PERIOD. ALL
INDICATIONS FROM THESE MODELS SUGGEST THE OHIO VALLEY SHORTWAVE
TROUGH IS NOT THE CAUSE FOR THE PRECIPITATION...BUT ACTUALLY 2
NORTHERN STREAM SHORTWAVE TROUGHS DIGGING DOWN THROUGH THE AREA
AND LINGERING WEAK MID LEVEL FRONTOGENESIS FROM TONIGHT. HARD TO
SAY REALLY WHAT SOLUTION WILL END UP VERIFYING...THE DRY ECMWF OR
THE WETTER GFS/CANADIAN/NAM... BUT EVEN THE WETTER SOLUTION DOES
NOT LOOK TO AMOUNT TO MUCH ACCUMULATION. CONSENSUS WARRANTS
MAINTAINING AT LEAST A 20 PERCENT CHANCE OVER TAYLOR/CLARK
COUNTIES ON FRIDAY...INCREASING CHANCES TO 30-40 PERCENT FRIDAY
NIGHT...THEN DECREASING TOWARDS 20-30 PERCENT BY SATURDAY
AFTERNOON. ALSO BELIEVE THE CHANCES ARE NEEDED AS EVEN THE ECMWF
SHOWS THE 2 NORTHERN STREAM SHORTWAVE TROUGHS. WHETHER WE GET
PRECIPITATION OR NOT...ALL MODELS AGREE ON PLENTY OF CLOUD COVER.
DESPITE THESE CLOUDS...CONSENSUS OF GUIDANCE SUGGESTS TEMPERATURES
WILL BE WARMER THAN WHAT HAS BEEN SEEN RECENTLY. SOME OF THIS IS
DUE TO SLIGHTLY WARMER AIR GETTING PULLED UP TOWARDS THE AREA
AROUND THE SYSTEM TRACKING INTO THE OHIO VALLEY.
OF THE TWO AFOREMENTIONED SHORTWAVE TROUGHS...THE SECOND ONE IS
MUCH MORE POTENT...DIGGING INTO LAKE SUPERIOR AND UPPER MICHIGAN
SATURDAY NIGHT. SOME LIGHT SNOW COULD OCCUR ACROSS AT LEAST
WISCONSIN PORTIONS OF THE AREA SATURDAY NIGHT AS THIS TROUGH DIGS
SOUTH. MORE IMPORTANTLY IS THE COLD SHOT OF AIR FOLLOWING IN ITS
WAKE...WHICH LIKE THE ONE COMING IN TONIGHT IS SHALLOW AS SEEN IN
925MB VERSUS 850MB PROGS. THE 12.00Z ECMWF IS BY FAR THE COLDEST
BRINGING 925MB TEMPS DOWN TO -13 TO -20C AT 18Z SUNDAY. HIGHS AT A
MINIMUM ARE LIKELY IN THE LOW TO MID TEENS...AND IF THE ECMWF IS
RIGHT TAYLOR COUNTY DOES NOT REACH 10 ABOVE.
LOOKING AHEAD TO NEXT WEEK...12.00Z ECMWF/GFS/CANADIAN/GFS ENSEMBLES
AGREE ON A NORTHWEST FLOW PATTERN FOR EARLY IN THE WEEK WITH
TROUGHING OVER THE GREAT LAKES. DESPITE BEING IN THE TROUGH AND
NORTHWEST FLOW...ITS ACTUALLY A WARM ADVECTION PATTERN IN THE LOW
LEVELS. THUS...LOW PRECIPITATION CHANCES ARE NEEDED...ESPECIALLY
ACROSS WISCONSIN WHERE THE FORCING IS STRONGEST. SOME HINTS THAT THE
FORCING WEAKENS ON TUESDAY...ENOUGH SO THAT CHANCES ARE ONLY INCLUDE
UP AROUND TAYLOR COUNTY. AS WE HEAD TOWARDS WEDNESDAY A POTENT
TROUGH STARTS DIGGING INTO THE PACIFIC NORTHWEST...PRODUCING ZONAL
FLOW DOWNSTREAM. THAT IS IF YOU BELIEVE THE ECMWF...BECAUSE THE GFS
DIGS A SHORTWAVE TROUGH DOWN INTO THE OHIO VALLEY. BOTH MODELS
SUGGEST DRY CONDITIONS...BUT THERE ARE MASSIVE TEMPERATURE
DIFFERENCES. GIVEN A SIMILAR SPLIT IN THE GFS ENSEMBLES...HAVE SPLIT
THE DIFFERENCE FOR NOW ON TEMPS.
FARTHER OUT...IT APPEARS AFTER A BRIEF POSSIBLE WARM UP ON WEDNESDAY
AND THURSDAY...ANOTHER BIG SURGE OF ARCTIC AIR LOOKS POISED TO DROP
DOWN INTO THE NORTH CENTRAL U.S. HEADING INTO THE FIRST OFFICIAL
WEEKEND OF WINTER.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z THURSDAY NIGHT)
ISSUED AT 1109 PM CST WED DEC 11 2013
WEAK AREA OF LOW PRESSURE OVER EASTERN NORTH DAKOTA WILL MOVE
RAPIDLY SOUTHEAST OVERNIGHT. A BAND OF LIGHT SNOW AHEAD OF THE LOW
IS PRESENTLY EXPECTED TO PRIMARILY MISS BOTH TAF SITES. COULD SEE
A FEW SNOWFLAKES AS IT GOES BY...BUT NOT ENOUGH TO REDUCE THE
VISIBILITY VERY MUCH IF AT ALL AND HAVE TAKEN THE MVFR VISIBILITY
RESTRICTIONS OUT OF BOTH TAF SITES. CEILINGS UP STREAM SOUTH OF
WHERE THE SNOW IS FALLING HAVE REMAINED VFR AND REFLECTED THIS
TREND IN BOTH TAFS AS WELL. ONCE THE SNOW BAND MOVES
PAST...MAINLY JUST HIGH LEVEL CLOUDS EXPECTED TO BE OVER THE
REGION FOR A GOOD SHARE OF THE DAY. THE NEXT WEAK SHORT WAVE
TROUGH WILL START TO APPROACH THURSDAY AFTERNOON AND IS EXPECTED
TO SPREAD A MID LEVEL DECK OF VFR CLOUDS ACROSS THE AREA.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
WI...WIND CHILL ADVISORY UNTIL 6 AM CST EARLY THIS MORNING FOR WIZ017-
029-032>034-041>044-053>055-061.
MN...WIND CHILL ADVISORY UNTIL 6 AM CST EARLY THIS MORNING FOR MNZ079-
086>088-094>096.
IA...WIND CHILL ADVISORY UNTIL 6 AM CST EARLY THIS MORNING FOR
IAZ008>011-018-019-029-030.
&&
$$
SHORT TERM...AJ
LONG TERM...AJ
AVIATION...04
AREA FORECAST DISCUSSION
NWS DENVER/BOULDER CO
313 AM MST THU DEC 12 2013
.SHORT TERM...DRY WNW FLOW ALOFT WILL BE OVER THE AREA TODAY THRU
TONIGHT. MAIN CONCERN FOR TODAY WILL BE HIGHS OVER NERN CO. SNOW
COVER STILL EXISTS OVER ERN LARIMER INTO CENTRAL WELD AND OVER THE
PALMER DIVIDE. OVERALL LOW LEVEL WINDS FIELDS WILL BE LIGHT SO
THERE WILL NOT BE MUCH OF A DOWNSLOPE COMPONENT OVER THE PLAINS
ALTHOUGH THERE WILL BE PLENTY OF SUN. SO THE BIG QUESTION IS WILL
THE LOW LEVEL INVERSIONS BE BKN OR NOT AS THERE WILL BE 5 TO 6
DEGREES C OF WARMING JUST ABV THE SFC.
THE NAM AND GFS PRETTY MUCH SHOW NO INVERSIONS ANYWHERE WITH
READINGS IN THE 40S ACROSS THE PLAINS WITH HIGHS IN THE LOWER 50S
AROUND DENVER. MEANWHILE THE HRRR AND TO SOME EXTENT THE RAP SHOW
INVERSIONS NOT BREAKING IN THE SNOW COVERED AREAS AS READINGS HOLD
IN THE 30S. IN ADDITION THE HRRR SHOWS QUITE A CONTRAST OVER THE
DENVER METRO AREA WITH READINGS NEAR 50 OVER THE SRN SUBURBS WHILE
IN NRN AREAS HIGHS STAY IN THE 35 TO 40 RANGE. THERE MAY END UP
BEING A WK DENVER CYCLONE WHICH ALLOWS FOR NLY SFC FLOW OVER THE NRN
SUBURBS THAT ALLOWS FOR SOME OF THE COOLER SFC TEMPS OVER WELD
COUNTY TO MOVE SOUTH SO CAN NOT COMPLETELY IGNORE WHAT THE HRRR
SHOWS. FOR NOW WILL KEEP READINGS COOLER THAN GUIDANCE FROM NORTH
OF DENVER TO FORT COLLINS TO GREELEY AND TOWARDS LIMON. FURTHER
SOUTH WILL HAVE HIGHS IN THE 45 TO 50 DEGREE RANGE AND OVER THE
FAR NERN CORNER.
.LONG TERM...MODELS HAVE A COUPLE WEAK UPPER TROUGHS TO MOVE
ACROSS THE CWA. BOTH WITH SLIGHTLY COOLER AIMASSES. THE FIRST ON
FRIDAY MORNING...THEN ANOTHER FRIDAY NIGHT LATE/EARLY SATURDAY
MORNING. BY SATURDAY AFTERNOON AND NIGHT...FAIRLY STRONG
NORTHERLY FLOW ALOFT IS PROGGED. THERE IS WEAK UPWARD SYNOPTIC
SCALE ENERGY PROGGED FOR THE CWA FRIDAY INTO FRIDAY NIGHT...THEN
ALL DOWNWARD MOTION SATURDAY AND SATURDAY NIGHT. THE LOW LEVEL
WINDS ARE PROGGED TO GO TO UPSLOPE FRIDAY AFTERNOON AND EVENING.
MORE NORMAL DIURNAL PATTERNS ARE PROGGED FOR SATURDAY. FOR
MOISTURE...IN INCREASES SOMEWHAT FRIDAY...WITH THE BEST FRIDAY
EVENING OVER THE MOUNTAINS. MOISTURE DRIES OUT LATE FRIDAY
NIGHT...AND THERE ISN`T MUCH SATURDAY OR SATURDAY NIGHT. THE QPF
FIELDS SHOW A TINY AMOUNT OF MEASURABLE SNOWFALL OVER THE HIGH
MOUNTAINS FRIDAY EVENING...BUT ONLY ON THE GFS. WILL KEEP POPS IN
FRIDAY NIGHT...MOSTLY OVER JUST THE HIGH MOUNTAINS. FOR
TEMPERATURES...FRIDAY`S HIGHS ARE 2-4 C COOLER THAN TODAY`S.
SATURDAY`S ARE SIMILAR TO FRIDAY`S. FOR THE LATER DAYS...SUNDAY
THROUGH WEDNESDAY...MODELS KEEP MODERATE NORTHWESTERLY FLOW ALOFT
FOR THE CWA SUNDAY AND MONDAY. ON TUESDAY AND WEDNESDAY IT IS
WEST-NORTHWESTERLY AND INCREASES IN SPEED....ESPECIALLY ON THE
GFS. THE GFS BRINGS A JET MAXIMUM OVER THE CWA...THE ECMWF KEEPS
IT WELL NORTH AND NORTHEAST. MOISTURE IS LACKING ALL FOUR DAYS.
&&
.AVIATION...VFR TODAY AND TONIGHT. WINDS WILL BE LIGHT SLY THIS
MORNING AND MORE SSW AFTER SUNRISE. FOR THIS AFTN THERE MAY BE A
WK DENVER CYCLONE WITH WINDS BECOME MORE NNE AFTER 20Z. BY 00Z
WINDS MAY BECOME MORE ESE AND THEN BACK TO DRAINAGE BY 02Z.
&&
.BOU WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...RPK
LONG TERM....RJK
AVIATION...RPK
AREA FORECAST DISCUSSION
NWS TAUNTON MA
702 AM EST THU DEC 12 2013
.SYNOPSIS...
MUCH COLDER THAN NORMAL CONDITIONS MOVE ACROSS THE REGION TODAY
AND FRIDAY AS TWO ARCTIC FRONTS PUSH THROUGH. THE FIRST FRONT
SWEEPS THROUGH THE REGION EARLY THIS MORNING AND THE OTHER MIDDAY
FRIDAY. BOTH ARCTIC FRONTS MAY BE ACCOMPANIED BY BRIEF SNOW
SQUALLS. A COASTAL STORM WILL LIKELY BRING ACCUMULATING SNOWFALL
TO THE REGION LATE SATURDAY INTO EARLY SUNDAY. DRIER BUT COLD
WEATHER FOLLOWS FOR EARLY NEXT WEEK.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
7 AM UPDATE...
SUBTLE BUT ARCTIC FRONT MOVING ACROSS RI AND EASTERN MA EARLY
THIS MORNING WITH DEW PTS FALLING OFF INTO THE SINGLE DIGITS
BEHIND THE FRONT. EARLIER CLOUDS AND SNOW SQUALLS ASSOCIATED WITH
THE FRONT HAVE DISSIPATED. WATCHING AREA OF OCEAN EFFECT CLOUDS
FORMING OVER CAPE COD BAY AND MASS BAY AS ARCTIC AIRMASS STREAMS
ACROSS THE RELATIVELY WARM OCEAN WATERS. LATEST MESOSCALE MODELS
INCLUDING THE RAP13 AND HRRR KEEP ANY OCEAN EFFECT SNOWS WELL
OFFSHORE. THUS DRY WEATHER SHOULD PREVAIL ACROSS CAPE COD AND
NANTUCKET. PREVIOUS FORECAST CAPTURES THESE DETAILS NICELY SO NO
MAJOR CHANGES WITH THIS FORECAST UPDATE. EARLIER DISCUSSION BELOW.
==================================================================
LINE OF SNOW SHOWERS CONTINUES TO SLOWLY CROSS THE REGION AT 09Z
WITH -SN NOTED AT KORH. EXPECT LINE TO SLOWLY DISSIPATE AS IT
PUSHES S...BUT COULD DROP BRIEF SNOW SHOWERS ACROSS SOUTHERN AREAS
THROUGH 13Z-14Z.
ARCTIC FRONT WILL PUSH OFFSHORE BY 12Z AS DEWPTS HAVE DROPPED TO
THE SINGLE DIGITS ACROSS S NH ALREADY. EXPECT LINE OF CLOUDS
ASSOCIATED WITH THE SNOW SHOWERS TO PUSH OFFSHORE BY MID
MORNING. WILL SEE SOME MID AND HIGH CLOUDS CROSSING THE REGION
DURING THE DAY...BUT GENERALLY MOSTLY CLEAR SKIES EXCEPT ALONG THE
OUTER CAPE AND ISLANDS WHERE OCEAN EFFECT CLOUDS MAY DEVELOP AND
MOVE ONSHORE. MAY ALSO SEE SOME CLOUDS DRIFTING INTO SW NH/W MA
FROM THE LAKE EFFECT SNOW BANDS ACROSS NY STATE.
H925 TEMPS DROP TO -12C TO -15C BY EARLY AFTERNOON WITH VERY GOOD
MIXING ALLOWING NW WINDS TO PICK UP. EXPECT DAYTIME HIGHS ONLY IN
THE 20S...THOUGH MAY CRACK 30 ALONG THE IMMEDIATE S COAST. WITH
THE WIND...THOUGH...WIND CHILLS WILL RANGE FROM THE SINGLE DIGITS
OVER THE HIGHER TERRAIN OF S NH TO TEENS ELSEWHERE.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH 6 PM FRIDAY/...
TONIGHT...
SKIES WILL AVERAGE OUT PARTLY CLOUDY AS PATCHY MID AND HIGH CLOUDS
MOVE ACROSS. SOME LOWER CLOUD BANDS MAY CONTINUE TO PUSH INTO
WESTERN AREAS FROM NY STATE WITH CONTINUED LAKE EFFECT SNOWS. MID
LAYER CLOUDS WILL START TO INCREASE TOWARD DAYBREAK AHEAD OF NEXT
FRONT. ANOTHER VERY COLD NIGHT WITH LOWS IN THE TEENS...EXCEPT FOR
LOWER 20S ALONG THE IMMEDIATE COAST AND SOME SINGLE DIGITS OVER
THE HIGHER TERRAIN OF S NH.
FRIDAY...
EXPECT ANOTHER SHOT OF COLD AIR TO WORK OUT OF CANADA AS ANOTHER
SHORT WAVE/ARCTIC FRONT WORKS ACROSS THE REGION DURING THE DAY.
MODELS DO SHOW SOME MOISTURE WITH THIS SYSTEM AND...WITH TODAY/S
FRONT...COULD SEE ANOTHER BAND OF SNOW SHOWERS THOUGH WILL BE
TOUGH TO HOLD TOGETHER EXCEPT ACROSS SW NH/W MA ASSOCIATED WITH
LAKE EFFECT SNOW BANDS. HIGHS WILL BE IN THE MID 20S TO LOWER 30S.
&&
.LONG TERM /FRIDAY NIGHT THROUGH WEDNESDAY/...
HIGHLIGHTS...
*** ARCTIC COLD LINGERS INTO SAT ***
*** A PLOWABLE SNOWFALL REMAINS LIKELY SAT NGT/EARLY SUN ***
FRIDAY NIGHT...
A SECOND ARCTIC FRONT SLIPS SOUTH OF THE REGION FRI AFTN WITH A
REINFORCING SURGE OF POLAR AIR INTO SOUTHERN NEW ENGLAND. THIS SETS
THE STAGE FOR A ROUND OF WINTRY WEATHER LATE SAT INTO EARLY SUNDAY.
SAT/SUN...
00Z MODEL GUIDANCE HAS TRENDED TOWARD THE NORTHERN AND SOUTHERN
STREAMS REMAINING SEPARATE/UNPHASED REGARDING THE POTENTIAL EAST
COAST CYCLOGENESIS THIS WEEKEND. THERE IS GOOD MODEL AGREEMENT THAT
THE SOUTHERN STREAM SHORT WAVE WILL BECOME QUITE SHEARED AS IT
ENTERS THE COLD CONFLUENT FLOW ACROSS THE NORTHEAST. THIS RESULTS IN
A WEAKER SURFACE WAVE WITH LESS QPF...BUT ALSO A COLDER SOLUTION AS
SURFACE WAVE TRACKS FARTHER OFFSHORE WITH WEAKER THERMAL ADVECTION
INTO SOUTHERN NEW ENGLAND. THE GEFS MEAN TRACKS THE SURFACE LOW NEAR
NANTUCKET...WHILE THE 51 ENSEMBLE MEMBER OF THE ECENS TRACKS THE
SURFACE WAVE CLOSER TO THE 40N/70W BENCHMARK. THIS IS A SOUTHEAST
TREND FROM PREVIOUS RUNS. THE DETERMINISTIC 00Z GFS/ECMWF AND UKMET
ARE JUST ABOUT OVER THE BENCHMARK 12Z SUNDAY. THUS ALL MODEL
GUIDANCE HAS TRENDED WEAKER AND FARTHER OFFSHORE. THIS EVENT IS
STILL 2 DAYS AWAY SO NEW TRENDS ARE POSSIBLE. HOWEVER THINK ITS
PRUDENT TO RECOGNIZE THIS MAJOR SHIFT IN THE GUIDANCE AND TREND THE
FORECAST TOWARD LESS QPF AND SOMEWHAT COLDER.
AS FOR MODEL GUIDANCE...THE 00Z NAM WAS DISCARDED AS A NORTHERN
OUTLIER WITH ITS SURFACE LOW/CYCLONE TRACKING ALONG THE COASTAL
PLAIN OF SOUTHERN NEW ENGLAND. AS MENTIONED ABOVE THE CONSENSUS
TRACK /INCLUDING THE 51 MEMBER ECENS ENSEMBLE MEAN/ IS NOW CLOSER TO
THE 40N/70W BENCHMARK. THUS WILL BASE THIS FORECAST ON AN EVEN BLEND
OF 00Z GFS/ECMWF.
TIMING...AT THIS TIME RANGE PRECIP LOOKS TO ARRIVE SOMETIME SAT AFTN
WITH THE HEAVIEST PRECIP OCCURRING SAT NIGHT BEFORE TAPERING OFF SUN
MORNING.
QPF...WITH MODELS TRENDING TOWARD A MORE SHEARED LOW MODEL QPF
CONSENSUS (50/50 BLEND OF GFS/EC) IS LESS THAN PREVIOUS RUNS WITH
TOTAL QPF RANGING FROM 0.60 TO 0.80 INCHES.
PTYPE...GIVEN RECENT TRENDS TOWARD A WEAKER COASTAL LOW AND FARTHER
OFFSHORE TRACK...THE PROBABILITY OF A COLDER SOLUTION HAS INCREASED.
THIS TREND LEANS TOWARD MAINLY SNOW FOR MUCH OF SOUTHERN NEW ENGLAND
WITH MIXED PRECIP POSSIBLY AS FAR NORTHWARD INTO NORTHEAST
CT/NORTHERN RI AND THE GREATER BOSTON AREA. THIS IS TYPICAL FOR A
COASTAL LOW PASSING NEAR THE BENCHMARK. HOWEVER THE MIXED PRECIP
LINE MAY BE HELD FARTHER SOUTH GIVEN THE STRONG ARCTIC HIGH OVER
QUEBEC COMBINED WITH POSSIBLE COASTAL FRONT DEVELOPMENT IN RI AND
EASTERN-SOUTHEASTERN MA.
SNOWFALL POTENTIAL...THIS EVENT IS STILL 2 DAYS AWAY AND THE COASTAL
STORM HASN/T FORMED YET. THUS OUR PRELIMINARY SNOWFALL FORECAST IS
FOR THE POTENTIAL OF UP TO 6 INCHES OF SNOWFALL FOR MUCH OF THE
REGION...WITH POSSIBLY LESS ALONG THE SOUTH COAST INCLUDING CAPE COD
AND THE ISLANDS AS MIXED PRECIP MAY ENTER THIS REGION. COLD AIRMASS
AT THE ONSET MAY YIELD GREATER THAN A 10/1 SNOW TO LIQUID RATIOS.
THIS COMBINED WITH ANY MID LEVEL BANDING POTENTIAL INTRODUCES A LOW
RISK OF 6+ INCHES POSSIBLE. REGARDLESS OF EXACT SNOWFALL NUMBERS
THERE WILL BE SUFFICIENT SNOW AND POSSIBLY MIXED PRECIP TO HAVE A
SIGNIFICANT IMPACT ON TRAVEL WITH TREACHEROUS ROAD CONDITIONS LATE
SAT INTO EARLY SUNDAY.
UNCERTAINTY...AS MENTIONED ABOVE THIS POTENTIAL EVENT IS STILL 2
DAYS AWAY AND THE STORM HASN/T FORMED YET. THUS ADDITIONAL FORECAST
CHANGES ARE LIKELY AS WE NEAR THE EVENT. ONE POSSIBLE OUTCOME WE
WILL HAVE TO BE ON GUARD FOR IS THE POTENTIAL FOR EVEN A
WEAKER/SHEARED SURFACE LOW YIELDING LESS QPF AND TRACKING FARTHER
OFFSHORE. THIS WOULD ALSO SHIFT THE RAIN/SNOW LINE FARTHER
SOUTHEAST ALONG WITH AXIS OF HEAVIEST SNOWFALL.
MON/TUE/WED...LOOKS FAIRLY QUIET BUT COLD /ALTHOUGH NOT AS COLD AS
TODAY AND FRI/ WITH LONG WAVE TROUGH AND ASSOCIATED BELOW NORMAL
HEIGHTS LINGERING ACROSS THE NORTHEAST.
&&
.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...
NO MAJOR CHANGES TO 12Z TAFS. HIGH CONFIDENCE FOR VFR AND DRY
WEATHER TODAY. EARLIER DISCUSSION BELOW.
================================================================
TODAY-TONIGHT...VFR CONDITIONS. MAY SEE LOCAL MVFR CIGS ACROSS
OUTER CAPE COD AND NANTUCKET WITH OCEAN EFFECT CLOUDS. LOW PROB OF
SNOW SHOWERS LATE TODAY AND TONIGHT FROM KACK-KMVY AND OUTER CAPE
COD.
FRIDAY...MAINLY VFR CONDITIONS. WINDS SHIFT TO N WITH ANOTHER SHOT
OF COLDER AIR. LOW PROB OF MVFR CIGS ALONG COAST...ESPECIALLY CAPE
COD AND THE ISLANDS.
KBOS TAF...HIGH CONFIDENCE IN TAF.
KBDL TAF...HIGH CONFIDENCE IN TAF.
OUTLOOK...FRIDAY NIGHT THROUGH MONDAY...
MODERATE TO HIGH CONFIDENCE.
IFR-LIFR CIGS/VSBYS SAT AND SUN IN SNOW POSSIBLY MIXING WITH
SLEET/FREEZING RAIN AND/OR ALONG THE SOUTH COAST INCLUDING CAPE
COD AND THE ISLANDS. UP TO 6 INCHES OF SNOWFALL POSSIBLE WITH LESS
ALONG SOUTH COAST. INCREASING EAST-NORTHEAST WINDS FOR COASTAL
TERMINALS WITH NORTHERLY FLOW THROUGH THE INTERIOR. CONDITIONS
IMPROVE INTO SUNDAY AS WINDS BACK WEST-NORTHWESTERLY BECOMING
BLUSTERY.
MONDAY...MODERATE CONFIDENCE FOR VFR AND MAINLY DRY WEATHER.
&&
.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.
TODAY...EXPECT W-NW WINDS TO GUST UP TO 20-25 KT EARLY...THEN WILL
DIMINISH BY MIDDAY. HOWEVER...SEAS ON THE OUTER WATERS WILL REMAIN
ABOVE 5 FT SO HAVE KEPT SMALL CRAFT GOING THERE. MAY SEE REDUCED
VSBYS IN OCEAN EFFECT SNOW SHOWERS.
TONIGHT...NW WINDS WILL PICK UP AGAIN ACROSS THE WATERS SO HAVE
SMALL CRAFTS UP FOR ALL WATERS. THERE IS A LOW CHANCE FOR GALE
GUSTS TOWARD DAYBREAK OVER THE OUTER WATERS E AND S OF NANTUCKET.
LIGHT FREEZING SPRAY LIKELY LATE NEAR NANTUCKET. OCEAN EFFECT SNOW
SHOWERS WILL LOWER VSBYS.
FRIDAY...W WINDS WILL CONTINUE TO GUST UP TO 25-30 KT...SHIFTING
BACK TO NW WITH ANOTHER COLD FRONTAL PASSAGE. CONTINUED LOW
CHANCE OF GALE GUSTS E AND S OF NANTUCKET THROUGH MIDDAY. LIGHT
FREEZING SPRAY LIKELY NEAR NANTUCKET. OCEAN EFFECT SNOW SHOWERS
CONTINUE WITH REDUCED VSBYS.
OUTLOOK...FRIDAY NIGHT THROUGH MONDAY...MODERATE CONFIDENCE.
COASTAL LOW EXITS MID ATLC STATES AND TRACKS NEAR THE 40N/70W
BENCHMARK SUNDAY MORNING. LOW TO MODERATE PROBABILITY FOR EAST-
NORTHEAST GALES. LOW RACES OUT TO SEA LATER SUN FOLLOWED BY GUSTY NW
WINDS LATER SUN INTO MON.
&&
.TIDES/COASTAL FLOODING...
THE RISK FOR COASTAL FLOODING APPEARS LOWER THAN EARLIER THOUGHT.
COASTAL STORM LATE SAT INTO SUN WILL NOT BE AS STRONG AS EARLIER
PREDICTED. HOWEVER ARCTIC HIGH PRES OVER QUEBEC WILL COMBINE WITH
THE WEAKER COASTAL LOW FOR A PERIOD OF STRONG ONSHORE WINDS ALONG
WITH A MODEST STORM SURGE AND WAVE ACTION OFFSHORE. ASTRONOMICAL
TIDES ARE FAIRLY LOW. FOR EXAMPLE ASTRO TIDES AT BOSTON SUN
MORNING ARE AROUND 10.3 FT. A STORM SURGE OF 1.0 FT TO 1.5 FT IS
EXPECTED WITH A LOW PROBABILITY OF SURGE VALUES NEAR 2 FT ALONG
WITH WAVES 10-15 FT OFF THE EASTERN MA COASTLINE. THIS WILL LIKELY
FALL SHORT OF PRODUCING COASTAL FLOODING FOR THE EASTERN MA
COASTLINE. HOWEVER THIS EVENT IS STILL 2 DAYS AWAY AND STORM
INTENSITY AND TRACK CAN CHANGE. THEREFORE THE WORST CASE SCENARIO
APPEARS TO BE A LOW RISK OF MINOR COASTAL FLOODING FOR THE SUN
MORNING HIGH TIDE ALONG THE EASTERN MA COASTLINE. THE MORE LIKELY
SCENARIO IS FOR NO COASTAL FLOODING.
&&
.BOX WATCHES/WARNINGS/ADVISORIES...
CT...NONE.
MA...NONE.
NH...NONE.
RI...NONE.
MARINE...SMALL CRAFT ADVISORY FROM MIDNIGHT TONIGHT TO 5 PM EST FRIDAY
FOR ANZ231-232-235-237-251.
SMALL CRAFT ADVISORY FROM 1 AM TO 5 PM EST FRIDAY FOR ANZ230-
233-234-236.
SMALL CRAFT ADVISORY UNTIL 5 PM EST FRIDAY FOR ANZ250-254>256.
&&
$$
SYNOPSIS...NOCERA/EVT
NEAR TERM...NOCERA/EVT
SHORT TERM...EVT
LONG TERM...NOCERA
AVIATION...NOCERA/EVT
MARINE...NOCERA/EVT
TIDES/COASTAL FLOODING...
AREA FORECAST DISCUSSION...UPDATED
NWS ALBUQUERQUE NM
500 AM MST THU DEC 12 2013
.AVIATION...
12Z TAF CYCLE
RAIN AND HIGH TERRAIN SNOW WILL MOVE INTO THE AREA FROM THE SOUTH
TODAY AS AN UPPER LEVEL LOW PRESSURE SYSTEM APPROACHES FROM THE
SW. TONIGHT...MODELS DEPICT THE INITIAL WAVE OF PRECIPITATION
SHIFTING EAST OF NEW MEXICO WITH MORE ACTIVITY IN THE FORM OF
MAINLY SNOW SHIFTING INTO CENTRAL AND WESTERN AREAS FROM THE WEST
WITH THE WEAKENING UPPER LEVEL STORM SYSTEM AND A PACIFIC COLD
FRONT. A FEW INCHES OF SNOW ACCUMULATION WILL BE POSSIBLE IN THE
WESTERN MOUNTAINS OVERNIGHT WITH LIGHTER AMOUNTS AT LOWER
ELEVATIONS ALONG AND W OF THE CENTRAL MT CHAIN. MVFR CONDITIONS
SHOULD BE COMMON WITH THE PRECIPITATION AS IT STARTS TODAY...THEN
PERIODS OF IFR CONDITIONS ARE EXPECTED ACROSS MUCH OF
WESTERN...CENTRAL AND SOUTHEAST PORTIONS OF THE FORECAST AREA
TONIGHT. MODELS SUGGEST FOG AND LOW CLOUDS COULD PRODUCE LIFR
CONDITIONS LATE TONIGHT IN ROSWELL. FLIGHT CATEGORY RESTRICTIONS
ARE EXPECTED TO LINGER IN MANY LOCATIONS WELL INTO FRIDAY AS THE
BAJA SYSTEM GRADUALLY EXITS AND ANOTHER WEAKER UPPER TROUGH MOVES
IN FROM THE NW KEEPING SHOWERS ACTIVE. NW WINDS WILL ALSO
STRENGTHEN FRIDAY...ESPECIALLY E OF THE CENTRAL MTS.
44
&&
.PREV DISCUSSION...303 AM MST THU DEC 12 2013...
WITH THE EXCEPTION OF A BRIEF BOUT OF RAIN/SNOW TODAY/TONIGHT ACROSS
CENTRAL AND WESTERN NM THE OVERALL PATTERN WILL REMAIN RELATIVELY
TRANQUIL THRU THE NEXT 7 DAYS. CURRENTLY A DEEP FETCH OF SUBTROPICAL
MOISTURE SURGING NE OUT OF THE EQUATORIAL PACIFIC WILL SLIDE OVER
SOUTHERN NM AHEAD OF A WEAK UPPER LOW OVER SOCA. THE LATEST HRRR
AND RUC SOLUTIONS SLOW DOWN TIMING OF PRECIP FOR TODAY SO LOWERED
POPS SUBSTANTIALLY THIS MORNING. THE WPC PROBABILISTIC QPF (PQPF)
INDICATES THE BEST SHOT FOR MEASURABLE IN THE SE WILL BE NOON TO
EARLY EVENING. 700MB WARM ADVECTION WITH THIS FETCH WILL RAISE
SNOW LEVELS TO ABOVE 9000 FT. TEMPS EXPECTED TO WARM ABOVE FREEZING
BY THE TIME PRECIP ARRIVES OVER THE AREA THUS SNOW ACCUMS WILL BE
ABOVE RUIDOSO.
MADE SOME NOTABLE CHANGES TO POP DISTRIBUTION FOR CENTRAL/WESTERN
NM LATE TODAY AND TONIGHT. TRENDED TOWARD SREF/GEFS AND WPC PQPF...
WHICH FOCUSES GREATEST CHANCES ALONG THE CONT DVD TONIGHT THEN THE
CENTRAL MT CHAIN/ABQ METRO AREA EARLY FRIDAY. COLD ADVECTION WITH
THE UPPER COLD CORE WILL ALLOW FOR RAIN TO SNOW...HOWEVER QPF IS
LIGHT...SO EXPECT HIGHEST SNOW AMOUNTS OVER HIGHEST TERRAIN. WILL
ISSUE SPS AGAIN SINCE CONFIDENCE ON TIMING/LOCATION OF COLD AIR
AND PRECIP IS TOO LOW FOR ANY ADVISORIES. ACCUMS LOOK MARGINAL TOO
EVEN IF BEST PRECIP COINCIDES WITH COLD AIR AND INSTABILITY.
AFTER THIS QUICK HIT OF RAIN/SNOW COLDER TEMPS WILL AGAIN SLIDE OVER
THE STATE THIS WEEKEND WITH A SERIES OF WEAK WAVES IN NW FLOW.
OTHERWISE IT WILL REMAIN QUIET THRU NEXT WEEK AS TEMPS MODERATE BACK
NEAR TO SLIGHTLY ABV NORMAL. PERIODIC GUSTY BREEZES IN NW FLOW ARE
LIKELY ALONG WIND PRONE AREAS EAST OF THE CENTRAL MT CHAIN.
GUYER
.FIRE WEATHER...
POOR VENTILATION IS EXPECTED AREAWIDE TODAY AS A LOW PRESSURE SYSTEM
THAT HAS BEEN STALLED OFF THE UPPER BAJA COAST BEGINS TO SHIFT
NORTHEASTWARD TOWARD NM. THE BULK OF THE MOISTURE WITH THE SYSTEM
WILL BE ASSOCIATED WITH THE SUBTROPICAL JET...WHICH WILL SHIFT
EASTWARD ACROSS SOUTHERN NM TODAY. MODELS AND OUR FORECAST GRIDS
HAVE SLOWED THE ARRIVAL OF THIS MOISTURE...WITH RAIN AND VERY HIGH
MOUNTAIN SNOWS FAVORING LOCATIONS ALONG AND SOUTH OF HIGHWAY 60 THIS
AFTERNOON. INSTABILITY LOOKS SUFFICIENT FOR A FEW THUNDERSTORMS TO
DEVELOP OVER THE SW MOUNTAINS THIS AFTERNOON...TOO. THE UPPER LEVEL
LOW AND A PACIFIC COLD FRONT ARE THEN PROGGED TO BRING MODEST
MOISTURE AND COLDER TEMPERATURES TO WESTERN AREAS...AND TO A LESSER
EXTENT CENTRAL AND SOUTHERN AREAS...TONIGHT. THE BAJA SYSTEM WILL
EXIT EASTWARD DURING THE AFTERNOON FRIDAY...BUT A SECONDARY UPPER
LOW RIGHT ON ITS HEELS WILL CROSS THE AREA FROM THE NORTHWEST...
KEEPING SHOWERS IN THE FORECAST FOR CENTRAL AND WESTERN AREAS FRIDAY
AND FRIDAY NIGHT. BY LATE FRIDAY...A FEW INCHES OF SNOW ACCUMULATION
WILL BE POSSIBLE IN THE WESTERN MOUNTAINS...WITH LIGHTER AMOUNTS
ACROSS THE REMAINDER OF THE HIGH TERRAIN. FROM THURSDAY THROUGH
FRIDAY NIGHT...LIQUID AND LIQUID EQUIVALENT PRECIPITATION SHOULD
TOTAL AROUND A QUARTER INCH ACROSS SOUTHERN PARTS OF THE FIRE
WEATHER FORECAST AREA...WITH A TENTH OF AN INCH POSSIBLE IN
LOCATIONS AS FAR NORTH AS THE CHUSKA MOUNTAINS AND ALBUQUERQUE. A
FEW HUNDREDTHS OF AN INCH WILL BE POSSIBLE FROM FARMINGTON TO SANTA
FE AND PORTALES.
IN THE WAKE OF THE PACIFIC COLD FRONT...W AND NW WINDS WILL PICK UP
FRIDAY AS A SPEED MAXIMUM IN THE POLAR JET ROUNDS THE BASE OF THE
SECONDARY UPPER TROUGH AND CROSSES SOUTHERN NM. MEANWHILE...A
SURFACE LOW WILL SHIFT SOUTHEASTWARD FROM SE CO OVER THE TX
PANHANDLE KEEPING THE SURFACE PRESSURE GRADIENT TIGHT ACROSS THE
PLAINS. THE STRONGEST NW WINDS SHOULD BE FOUND ALONG AND SOUTH OF
I-40...WITH GUSTS FROM 40 TO PERHAPS 50 MPH EAST OF THE
SANDIA/MANZANO AND GALLINAS MOUNTAINS TO THE PECOS RIVER. BREEZY
CONDITIONS WILL EXTEND EAST OF THERE TO THE TX BORDER.
FORTUNATELY...HUMIDITIES WILL REMAIN ABOVE CRITICAL THRESHOLDS.
BECAUSE OF THE STRONGER WINDS...THERE WILL BE SOME VENTILATION
IMPROVEMENT FRIDAY ALONG AND SOUTH OF I-40...WITH POOR VENTILATION
LINGERING ACROSS MUCH OF THE NORTH.
ONE LAST WEAK AND DRY UPPER TROUGH WILL DIVE SOUTHEASTWARD ACROSS
THE FORECAST AREA SATURDAY...PROMPTLY BEHIND FRIDAYS SECONDARY
SYSTEM. THIS THIRD TROUGH WILL KEEP COLD AIR ADVECTION IN PLACE FOR
ONE LAST DAY. HIGH TEMPERATURES ARE EXPECTED TO BOTTOM OUT SATURDAY
AROUND 3 TO 10 DEGREES BELOW NORMAL. VENTILATION WILL BE POOR
AREAWIDE...EXCEPT FOR SOME IMPROVEMENT ACROSS THE FAR EASTERN PLAINS
DUE TO GUSTY NORTH WINDS LINGERING BEHIND A BACK DOOR COLD FRONT
THAT WILL SINK SOUTHWARD THROUGH THE PLAINS FRIDAY NIGHT.
DRY NW FLOW ALOFT WILL PERSIST THROUGH THE MIDDLE OF THE COMING
WEEK. WEATHER SYSTEMS WILL PASS FAR ENOUGH NORTH TO KEEP
PRECIPITATION OUT OF THE FORECAST FOR NORTHERN AND CENTRAL NM. A
WARMING TREND WILL DEVELOP SUNDAY THROUGH TUESDAY WITH HIGH
TEMPERATURES REACHING ABOVE NORMAL IN MOST LOCATIONS AS EARLY AS
MONDAY. A BACK DOOR COLD FRONT SHOULD THEN DROP SOUTHWARD THROUGH
THE PLAINS TUESDAY NIGHT COOLING TEMPERATURES ACROSS THE EAST FOR
WEDNESDAY. OTHERWISE...VENTILATION WILL GENERALLY BE POOR...EXCEPT
FOR PERIODS OF IMPROVEMENT ACROSS THE EAST CENTRAL PLAINS.
44
&&
.ABQ WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS BISMARCK ND
951 AM CST THU DEC 12 2013
.UPDATE...
ISSUED AT 934 AM CST THU DEC 12 2013
AT 9 AM CST...A WARM FRONTAL BOUNDARY ACROSS NORTHEAST MONTANA
AND SOUTHWEST NORTH DAKOTA WILL BE THE FOCUS FOR LIGHT SNOW ACROSS
NORTH CENTRAL NORTH DAKOTA. THE CHANCE OF SNOW WILL INCREASE
ACROSS THE NORTH CENTRAL TONIGHT AND FRIDAY. FOR TODAY...EXPECT
LITTLE SNOW ACROSS THE SOUTH. KEPT 20-30 POPS ACROSS THE NORTH.
TEMPERATURES ACROSS THE REGION WILL REMAIN COOL NORTHEAST. SHOULD
GET CLOSE TO THE FREEZING MARK SOUTHWEST.
UPDATE ISSUED AT 643 AM CST THU DEC 12 2013
UPDATE FOR POPS AND TEMPERATURE TRENDS. BASED ON 11Z RAP GUIDANCE
AND RADAR/OBS TRENDS...HAVE EXPANDED AREA OF LIGHT SNOW SHOWERS TO
INCLUDE MOST OF THE FORECAST AREA THIS MORNING. THE FOCUS OF THE
SNOW LATER THIS AFTERNOON WILL BE THE FAR NORTH. HOWEVER...MOST
ACCUMULATING SNOW WILL OCCUR AFTER 00Z THIS EVENING.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 327 AM CST THU DEC 12 2013
THE HIGHLIGHT OF THE SHORT TERM IS A BREAK FROM THE ARCTIC
AIR...ESPECIALLY SOUTHWEST AND SOUTH CENTRAL TODAY...FOLLOWED BY
ACCUMULATING SNOW TONIGHT NORTH CENTRAL.
CONTINUED POPS THROUGH 15 UTC ACROSS THE NORTHWEST BASED UPON
LATEST RADAR TRENDS THROUGH 0945 UTC AND THE 08 UTC RAP WHICH IS THE
JUST ABOUT THE ONLY DETERMINISTIC MODEL CAPTURING THE LIGHT SNOW
PROPAGATING IN FROM NORTHEAST MONTANA AND SOUTHEAST SASKATCHEWAN
THIS MORNING.
A QUASI-STATIONARY FRONT ACROSS NORTHWEST THROUGH SOUTHEAST NORTH
DAKOTA THIS MORNING WILL SLOWLY PROPAGATE SOUTHWEST THROUGH THE
DAY AS A COLD FRONT. ON THE WARM SIDE OF THIS BOUNDARY WIDESPREAD
HIGHS IN THE 20S...AND PERHAPS A FEW LOWER 30S ACROSS THE FAR
SOUTHWEST ARE EXPECTED. IN CONTRAST...HIGHS IN THE SINGLE DIGITS
ARE FORECAST ACROSS THE TURTLE MOUNTAINS...WHICH IS IN LINE WITH
THE 00 UTC GUIDANCE CONSENSUS. AS THE LOW LEVEL BAROCLINIC ZONE
STRENGTHENS LATE THIS AFTERNOON AND INTO THE EVENING AS THE
SOUTHERN PERIPHERY OF ARCTIC HIGH PRESSURE BUILDS INTO NORTHERN
NORTH DAKOTA...A BAND OF LIGHT TO MODERATE SNOW IS EXPECTED TO
DEVELOP ACROSS NORTH CENTRAL AND NORTHEAST NORTH DAKOTA AS
FRONTOGENETICAL FORCING INCREASES. ONE TO THREE INCHES OF SNOW IS
EXPECTED FOR THE US HIGHWAY 2 CORRIDOR ACROSS THE NORTH CENTRAL.
AT THIS TIME...WILL HIGHLIGHT THE EVENT WITH AN SPS...ALSO
MENTIONING WIND CHILLS TO 25 BELOW AS ARCTIC AIR BUILDS SOUTH
COUPLED WITH EASTERLY WINDS OF 10-15 KTS WITH THE TIGHT PRESSURE
GRADIENT ON THE SOUTHERN PERIPHERY OF THE SURFACE HIGH.
.LONG TERM...(FRIDAY THROUGH WEDNESDAY)
ISSUED AT 327 AM CST THU DEC 12 2013
THE MAIN FORECAST ISSUE IS TIMING AND COVERAGE OF SEVERAL LIGHT
SNOW EVENTS THROUGH THE PERIOD.
ON FRIDAY...ANOTHER SURGE OF ARCTIC AIR WILL SPREAD SOUTH ACROSS
THE STATE. LIGHT SNOW WILL CONTINUE FRIDAY...WITH ADDITIONAL
ACCUMULATION FOCUSED ON THE NORTHERN COUNTIES. 1 TO 2 MORE INCHES
WILL BE POSSIBLE THROUGH FRIDAY NIGHT...WITH GENERALLY A LIGHT
DUSTING POSSIBLE IN CENTRAL AND SOUTHERN NORTH DAKOTA. ANOTHER
WEAK SHORT WAVE MAY SUPPORT LIGHT ACCUMULATIONS AGAIN SATURDAY
NIGHT. WIND CHILLS AROUND 25 BELOW ZERO ARE POSSIBLE FRIDAY NIGHT
AND SATURDAY NIGHT ACROSS THE NORTH. LOOKING AHEAD...THERE IS SOME
UNCERTAINTY AS TO HOW FAR EAST THE UPPER RIDGE AND MILDER AIR WILL
PUSH. THE SOUTHWEST PART OF THE STATE...AT THE LEAST...SHOULD WARM
INTO THE 20S AND EVEN LOWER 30S FROM SUNDAY THROUGH WEDNESDAY.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z FRIDAY MORNING) ISSUED AT 934
AM CST THU DEC 12 2013
AT 9 AM CST...A WARM FRONT EXTENDED ACROSS SOUTHWEST NORTH
DAKOTA. VFR CONDITIONS PREVAILED ACROSS THE SOUTH...FROM KDIK-KBIS-
KJMS. KISN-KMOT WILL BE GENERALLY BE VFR...BECOMING MVFR WITH
LIGHT SNOW AFTER 20Z.
&&
.BIS WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...WAA
AVIATION...WAA
AREA FORECAST DISCUSSION
NWS BISMARCK ND
647 AM CST THU DEC 12 2013
.UPDATE...
ISSUED AT 643 AM CST THU DEC 12 2013
UPDATE FOR POPS AND TEMPERATURE TRENDS. BASED ON 11Z RAP GUIDANCE
AND RADAR/OBS TRENDS...HAVE EXPANDED AREA OF LIGHT SNOW SHOWERS TO
INCLUDE MOST OF THE FORECAST AREA THIS MORNING. THE FOCUS OF THE
SNOW LATER THIS AFTERNOON WILL BE THE FAR NORTH. HOWEVER...MOST
ACCUMULATING SNOW WILL OCCUR AFTER 00Z THIS EVENING.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 327 AM CST THU DEC 12 2013
THE HIGHLIGHT OF THE SHORT TERM IS A BREAK FROM THE ARCTIC
AIR...ESPECIALLY SOUTHWEST AND SOUTH CENTRAL TODAY...FOLLOWED BY
ACCUMULATING SNOW TONIGHT NORTH CENTRAL.
CONTINUED POPS THROUGH 15 UTC ACROSS THE NORTHWEST BASED UPON
LATEST RADAR TRENDS THROUGH 0945 UTC AND THE 08 UTC RAP WHICH IS THE
JUST ABOUT THE ONLY DETERMINISTIC MODEL CAPTURING THE LIGHT SNOW
PROPAGATING IN FROM NORTHEAST MONTANA AND SOUTHEAST SASKATCHEWAN
THIS MORNING.
A QUASI-STATIONARY FRONT ACROSS NORTHWEST THROUGH SOUTHEAST NORTH
DAKOTA THIS MORNING WILL SLOWLY PROPAGATE SOUTHWEST THROUGH THE
DAY AS A COLD FRONT. ON THE WARM SIDE OF THIS BOUNDARY WIDESPREAD
HIGHS IN THE 20S...AND PERHAPS A FEW LOWER 30S ACROSS THE FAR
SOUTHWEST ARE EXPECTED. IN CONTRAST...HIGHS IN THE SINGLE DIGITS
ARE FORECAST ACROSS THE TURTLE MOUNTAINS...WHICH IS IN LINE WITH
THE 00 UTC GUIDANCE CONSENSUS. AS THE LOW LEVEL BAROCLINIC ZONE
STRENGTHENS LATE THIS AFTERNOON AND INTO THE EVENING AS THE
SOUTHERN PERIPHERY OF ARCTIC HIGH PRESSURE BUILDS INTO NORTHERN
NORTH DAKOTA...A BAND OF LIGHT TO MODERATE SNOW IS EXPECTED TO
DEVELOP ACROSS NORTH CENTRAL AND NORTHEAST NORTH DAKOTA AS
FRONTOGENETICAL FORCING INCREASES. ONE TO THREE INCHES OF SNOW IS
EXPECTED FOR THE US HIGHWAY 2 CORRIDOR ACROSS THE NORTH CENTRAL.
AT THIS TIME...WILL HIGHLIGHT THE EVENT WITH AN SPS...ALSO
MENTIONING WIND CHILLS TO 25 BELOW AS ARCTIC AIR BUILDS SOUTH
COUPLED WITH EASTERLY WINDS OF 10-15 KTS WITH THE TIGHT PRESSURE
GRADIENT ON THE SOUTHERN PERIPHERY OF THE SURFACE HIGH.
.LONG TERM...(FRIDAY THROUGH WEDNESDAY)
ISSUED AT 327 AM CST THU DEC 12 2013
THE MAIN FORECAST ISSUE IS TIMING AND COVERAGE OF SEVERAL LIGHT
SNOW EVENTS THROUGH THE PERIOD.
ON FRIDAY...ANOTHER SURGE OF ARCTIC AIR WILL SPREAD SOUTH ACROSS
THE STATE. LIGHT SNOW WILL CONTINUE FRIDAY...WITH ADDITIONAL
ACCUMULATION FOCUSED ON THE NORTHERN COUNTIES. 1 TO 2 MORE INCHES
WILL BE POSSIBLE THROUGH FRIDAY NIGHT...WITH GENERALLY A LIGHT
DUSTING POSSIBLE IN CENTRAL AND SOUTHERN NORTH DAKOTA. ANOTHER
WEAK SHORT WAVE MAY SUPPORT LIGHT ACCUMULATIONS AGAIN SATURDAY
NIGHT. WIND CHILLS AROUND 25 BELOW ZERO ARE POSSIBLE FRIDAY NIGHT
AND SATURDAY NIGHT ACROSS THE NORTH. LOOKING AHEAD...THERE IS SOME
UNCERTAINTY AS TO HOW FAR EAST THE UPPER RIDGE AND MILDER AIR WILL
PUSH. THE SOUTHWEST PART OF THE STATE...AT THE LEAST...SHOULD WARM
INTO THE 20S AND EVEN LOWER 30S FROM SUNDAY THROUGH WEDNESDAY.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z FRIDAY MORNING)
ISSUED AT 643 AM CST THU DEC 12 2013
MVFR CONDITIONS IN LIGHT SNOW ARE POSSIBLE AT KISN AND KMOT THIS
MORNING. ANOTHER WEAK SYSTEM WILL IMPACT WESTERN AND CENTRAL NORTH
DAKOTA THIS AFTERNOON AND INTO THE NIGHT. MVFR CONDITIONS IN STRATUS
AND FOG WILL OVERTAKE THE AREA WITH IFR CONDITIONS IN SNOW
DEVELOPING AT KMOT TONIGHT.
&&
.BIS WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE/LONG TERM...RP KINNEY
SHORT TERM/AVIATION...AYD
AREA FORECAST DISCUSSION
NWS BISMARCK ND
441 AM CST THU DEC 12 2013
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 327 AM CST THU DEC 12 2013
THE HIGHLIGHT OF THE SHORT TERM IS A BREAK FROM THE ARCTIC
AIR...ESPECIALLY SOUTHWEST AND SOUTH CENTRAL TODAY...FOLLOWED BY
ACCUMULATING SNOW TONIGHT NORTH CENTRAL.
CONTINUED POPS THROUGH 15 UTC ACROSS THE NORTHWEST BASED UPON
LATEST RADAR TRENDS THROUGH 0945 UTC AND THE 08 UTC RAP WHICH IS THE
JUST ABOUT THE ONLY DETERMINISTIC MODEL CAPTURING THE LIGHT SNOW
PROPAGATING IN FROM NORTHEAST MONTANA AND SOUTHEAST SASKATCHEWAN
THIS MORNING.
A QUASI-STATIONARY FRONT ACROSS NORTHWEST THROUGH SOUTHEAST NORTH
DAKOTA THIS MORNING WILL SLOWLY PROPAGATE SOUTHWEST THROUGH THE
DAY AS A COLD FRONT. ON THE WARM SIDE OF THIS BOUNDARY WIDESPREAD
HIGHS IN THE 20S...AND PERHAPS A FEW LOWER 30S ACROSS THE FAR
SOUTHWEST ARE EXPECTED. IN CONTRAST...HIGHS IN THE SINGLE DIGITS
ARE FORECAST ACROSS THE TURTLE MOUNTAINS...WHICH IS IN LINE WITH
THE 00 UTC GUIDANCE CONSENSUS. AS THE LOW LEVEL BAROCLINIC ZONE
STRENGTHENS LATE THIS AFTERNOON AND INTO THE EVENING AS THE
SOUTHERN PERIPHERY OF ARCTIC HIGH PRESSURE BUILDS INTO NORTHERN
NORTH DAKOTA...A BAND OF LIGHT TO MODERATE SNOW IS EXPECTED TO
DEVELOP ACROSS NORTH CENTRAL AND NORTHEAST NORTH DAKOTA AS
FRONTOGENETICAL FORCING INCREASES. ONE TO THREE INCHES OF SNOW IS
EXPECTED FOR THE US HIGHWAY 2 CORRIDOR ACROSS THE NORTH CENTRAL.
AT THIS TIME...WILL HIGHLIGHT THE EVENT WITH AN SPS...ALSO
MENTIONING WIND CHILLS TO 25 BELOW AS ARCTIC AIR BUILDS SOUTH
COUPLED WITH EASTERLY WINDS OF 10-15 KTS WITH THE TIGHT PRESSURE
GRADIENT ON THE SOUTHERN PERIPHERY OF THE SURFACE HIGH.
.LONG TERM...(FRIDAY THROUGH WEDNESDAY)
ISSUED AT 327 AM CST THU DEC 12 2013
THE MAIN FORECAST ISSUE IS TIMING AND COVERAGE OF SEVERAL LIGHT
SNOW EVENTS THROUGH THE PERIOD.
ON FRIDAY...ANOTHER SURGE OF ARCTIC AIR WILL SPREAD SOUTH ACROSS
THE STATE. LIGHT SNOW WILL CONTINUE FRIDAY...WITH ADDITIONAL
ACCUMULATION FOCUSED ON THE NORTHERN COUNTIES. 1 TO 2 MORE INCHES
WILL BE POSSIBLE THROUGH FRIDAY NIGHT...WITH GENERALLY A LIGHT
DUSTING POSSIBLE IN CENTRAL AND SOUTHERN NORTH DAKOTA. ANOTHER
WEAK SHORT WAVE MAY SUPPORT LIGHT ACCUMULATIONS AGAIN SATURDAY
NIGHT. WIND CHILLS AROUND 25 BELOW ZERO ARE POSSIBLE FRIDAY NIGHT
AND SATURDAY NIGHT ACROSS THE NORTH. LOOKING AHEAD...THERE IS SOME
UNCERTAINTY AS TO HOW FAR EAST THE UPPER RIDGE AND MILDER AIR WILL
PUSH. THE SOUTHWEST PART OF THE STATE...AT THE LEAST...SHOULD WARM
INTO THE 20S AND EVEN LOWER 30S FROM SUNDAY THROUGH WEDNESDAY.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z FRIDAY MORNING)
ISSUED AT 327 AM CST THU DEC 12 2013
IFR CONDITIONS IN LIGHT SNOW IS POSSIBLE AT KISN BETWEEN 09 AND 11
UTC THIS MORNING. ANOTHER WEAK SYSTEM WILL IMPACT WESTERN AND
CENTRAL NORTH DAKOTA THIS AFTERNOON AND INTO THE NIGHT. MVFR
CONDITIONS IN STRATUS ARE EXPECTED AT KISN/KJMS/KBIS/KDIK...WITH
IFR CONDITIONS IN SNOW AT KMOT.
&&
.BIS WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM/AVIATION...AYD
LONG TERM...RP KINNEY
YOU CAN SEE AN ILLUSTRATED VERSION OF THE FORECAST DISCUSSION AT
WWW.WEATHER.GOV/SEATTLE/GAFD/LATEST_WEBAFD.HTML
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
534 AM CST THU DEC 12 2013
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 329 AM CST THU DEC 12 2013
CURRENTLY AS OF 09Z...WATER VAPOR LOOP AND RAP 500MB HEIGHT ANALYSIS
SHOWED RIDGING OVER THE WESTERN U.S. INTO SOUTHWEST CANADA...AND
TROUGHING OVER EASTERN CANADA INTO THE GREAT LAKES. IN THE NORTHWEST
FLOW BETWEEN THE RIDGE AND TROUGH...A SHORTWAVE WAS NOTED OVER
NORTHWEST WISCONSIN. DPVA FORCING FROM THE SHORTWAVE COMBINED WITH
ISENTROPIC LIFT ON THE 275-280K SURFACES AS SUGGESTED BY THE RAP HAS
SPREAD LIGHT SNOW ACROSS THE NORTHEAST HALF OF THE FORECAST AREA. IN
ADDITION...THE CLOUDS AND A WARM ADVECTION SOUTHWEST WIND IN THE LOW
LEVELS HAS CAUSED TEMPERATURES TO CLIMB OVERNIGHT. THE BREEZE...
HOWEVER...HAS HELD WIND CHILLS DOWN TO 10 TO 20 BELOW ZERO SOUTHWEST
OF I-94 TO 20 TO 25 BELOW ZERO TO THE NORTH. REGARDING THE WARM
ADVECTION HIGHER ABOVE THE SURFACE...FROM 00Z SOUNDINGS...850MB
TEMPS WERE AROUND -20C OVER THE FORECAST AREA COMPARED TO -7C AT
BIS AND AROUND -10C AT ABR AND OAX. FARTHER UPSTREAM...PLENTY OF
HIGH CLOUDS REFLECTING PACIFIC MOISTURE WERE STREAMING INTO NORTH
DAKOTA IN THE WAKE OF THE SHORTWAVE.
FIRST...WITH RESPECT TO THE WIND CHILL HAZARDS...WILL LET THEM
EXPIRE AT 12Z. ALTHOUGH WIND CHILLS ARE IMPROVING...THERE IS ONLY A
FEW HOURS LEFT TO THE ADVISORY...AND THEY ARE STILL CHILL AS
MENTIONED ABOVE.
ONGOING SNOW EARLY THIS MORNING REMAINS ON TRACK TO QUICKLY EXIT THE
FORECAST AREA...LIKELY BY 7 AM...AS THE SHORTWAVE HEADS OFF TO LAKE
MICHIGAN BY 12Z. OTHERWISE...THE REST OF THE SHORT TERM GENERALLY
LOOKS QUIET PRECIPITATION-WISE AS THE UPPER LEVEL FLOW BECOMES MORE
ZONAL OVER THE NORTHERN U.S.. THE 12.00Z GFS/CANADIAN AND 12.03Z
SREF ALL SHOW SOME LIGHT SNOW OR FLURRIES FALLING LATE THIS
AFTERNOON INTO EARLY THIS EVENING FROM TAYLOR COUNTY NORTHWARD. THIS
LIGHT PRECIPITATION IS ASSOCIATED WITH WEAK BUT MAINTAINED
ISENTROPIC LIFT AND MID-LEVEL FRONTOGENESIS. DECIDED TO ADD SOME LOW
CHANCES ON THE ORDER OF 20 PERCENT TO TAYLOR COUNTY. DESPITE MAINLY
DRY WEATHER FOR THE NEXT 24 HOURS...WE SHOULD SEE QUITE A BIT OF
CLOUD COVER...ESPECIALLY OVER THE NORTH HALF OF THE FORECAST AREA.
THESE CLOUDS OF THE MID/HIGH LEVEL VARIETY REFLECT BOTH THE PACIFIC
MOISTURE FLOWING IN BEHIND THE CURRENT SHORTWAVE AS WELL AS THE
GENERAL WARM ADVECTION PATTERN. ADDITIONALLY...LATE TONIGHT...THE
FORECAST AREA LIES IN THE RIGHT ENTRANCE REGION OF AN UPPER JET
STREAK OVER THE UPPER GREAT LAKES...FAVORING CLOUDS.
WARMER TEMPERATURES ARE ON TRACK TODAY AS SOUTHWEST WINDS BRING UP
WARMER AIR OUT OF NEBRASKA. THE 24 HOUR CHANGE AT 850MB IS FAIRLY
IMPRESSIVE...FROM THE -20C OBSERVED BACK AT 00Z YESTERDAY EVENING TO
-2C TO -10C FOR THIS EVENING. WE CERTAINLY WILL NOT MIX TO THESE
VALUES GIVEN TIME OF YEAR...CLOUDS AND SNOW COVER...BUT DEFINITELY
WARMER NONETHELESS. COLDEST READINGS WILL REMAIN IN THE CHIMNEY
AREA. AS THE UPPER FLOW TURNS ZONAL TONIGHT...A COLD FRONT CURRENTLY
OVER SOUTHERN SASKATCHEWAN IS PROGGED TO SLIDE SOUTH THROUGH THE
FORECAST AREA. THE COLD AIR IS SHALLOW BEHIND THIS FRONT AS MUCH OF
THE TEMPERATURE FALL TAKES PLACE AT 925MB AND BELOW. 925MB TEMPS
FALL 6C ON A NORTH TO NORTHEAST WIND...SO WE SHOULD SEE A DECENT
TEMPERATURE DROP TONIGHT DESPITE CLOUDS IN PLACE.
.LONG TERM...(FRIDAY THROUGH WEDNESDAY)
ISSUED AT 329 AM CST THU DEC 12 2013
FOR FRIDAY THROUGH SATURDAY...ATTENTION TURNS TO AN UPPER LOW
CURRENTLY SITTING NEAR FAR SOUTHERN CALIFORNIA. 12.00Z MODELS
REMAIN CONSISTENT ON TRACKING THIS FEATURE INTO THE CENTRAL
PLAINS ON FRIDAY...THEN UP THROUGH THE OHIO VALLEY FRIDAY NIGHT
AND SATURDAY. THIS TRACK WOULD KEEP THE BULK OF THE SYSTEMS
PRECIPITATION... INCLUDING THE DEFORMATION SHIELD...SOUTHEAST OF
THE FORECAST AREA. 12.00Z ECMWF SHOWS A COMPLETELY DRY FORECAST
FOR THE AREA. HOWEVER...THE 12.00Z GFS/CANADIAN/NAM SUGGEST
POTENTIAL FOR LIGHT SNOW THROUGH THIS ENTIRE PERIOD. ALL
INDICATIONS FROM THESE MODELS SUGGEST THE OHIO VALLEY SHORTWAVE
TROUGH IS NOT THE CAUSE FOR THE PRECIPITATION...BUT ACTUALLY 2
NORTHERN STREAM SHORTWAVE TROUGHS DIGGING DOWN THROUGH THE AREA
AND LINGERING WEAK MID LEVEL FRONTOGENESIS FROM TONIGHT. HARD TO
SAY REALLY WHAT SOLUTION WILL END UP VERIFYING...THE DRY ECMWF OR
THE WETTER GFS/CANADIAN/NAM... BUT EVEN THE WETTER SOLUTION DOES
NOT LOOK TO AMOUNT TO MUCH ACCUMULATION. CONSENSUS WARRANTS
MAINTAINING AT LEAST A 20 PERCENT CHANCE OVER TAYLOR/CLARK
COUNTIES ON FRIDAY...INCREASING CHANCES TO 30-40 PERCENT FRIDAY
NIGHT...THEN DECREASING TOWARDS 20-30 PERCENT BY SATURDAY
AFTERNOON. ALSO BELIEVE THE CHANCES ARE NEEDED AS EVEN THE ECMWF
SHOWS THE 2 NORTHERN STREAM SHORTWAVE TROUGHS. WHETHER WE GET
PRECIPITATION OR NOT...ALL MODELS AGREE ON PLENTY OF CLOUD COVER.
DESPITE THESE CLOUDS...CONSENSUS OF GUIDANCE SUGGESTS TEMPERATURES
WILL BE WARMER THAN WHAT HAS BEEN SEEN RECENTLY. SOME OF THIS IS
DUE TO SLIGHTLY WARMER AIR GETTING PULLED UP TOWARDS THE AREA
AROUND THE SYSTEM TRACKING INTO THE OHIO VALLEY.
OF THE TWO AFOREMENTIONED SHORTWAVE TROUGHS...THE SECOND ONE IS
MUCH MORE POTENT...DIGGING INTO LAKE SUPERIOR AND UPPER MICHIGAN
SATURDAY NIGHT. SOME LIGHT SNOW COULD OCCUR ACROSS AT LEAST
WISCONSIN PORTIONS OF THE AREA SATURDAY NIGHT AS THIS TROUGH DIGS
SOUTH. MORE IMPORTANTLY IS THE COLD SHOT OF AIR FOLLOWING IN ITS
WAKE...WHICH LIKE THE ONE COMING IN TONIGHT IS SHALLOW AS SEEN IN
925MB VERSUS 850MB PROGS. THE 12.00Z ECMWF IS BY FAR THE COLDEST
BRINGING 925MB TEMPS DOWN TO -13 TO -20C AT 18Z SUNDAY. HIGHS AT A
MINIMUM ARE LIKELY IN THE LOW TO MID TEENS...AND IF THE ECMWF IS
RIGHT TAYLOR COUNTY DOES NOT REACH 10 ABOVE.
LOOKING AHEAD TO NEXT WEEK...12.00Z ECMWF/GFS/CANADIAN/GFS ENSEMBLES
AGREE ON A NORTHWEST FLOW PATTERN FOR EARLY IN THE WEEK WITH
TROUGHING OVER THE GREAT LAKES. DESPITE BEING IN THE TROUGH AND
NORTHWEST FLOW...ITS ACTUALLY A WARM ADVECTION PATTERN IN THE LOW
LEVELS. THUS...LOW PRECIPITATION CHANCES ARE NEEDED...ESPECIALLY
ACROSS WISCONSIN WHERE THE FORCING IS STRONGEST. SOME HINTS THAT THE
FORCING WEAKENS ON TUESDAY...ENOUGH SO THAT CHANCES ARE ONLY INCLUDE
UP AROUND TAYLOR COUNTY. AS WE HEAD TOWARDS WEDNESDAY A POTENT
TROUGH STARTS DIGGING INTO THE PACIFIC NORTHWEST...PRODUCING ZONAL
FLOW DOWNSTREAM. THAT IS IF YOU BELIEVE THE ECMWF...BECAUSE THE GFS
DIGS A SHORTWAVE TROUGH DOWN INTO THE OHIO VALLEY. BOTH MODELS
SUGGEST DRY CONDITIONS...BUT THERE ARE MASSIVE TEMPERATURE
DIFFERENCES. GIVEN A SIMILAR SPLIT IN THE GFS ENSEMBLES...HAVE SPLIT
THE DIFFERENCE FOR NOW ON TEMPS.
FARTHER OUT...IT APPEARS AFTER A BRIEF POSSIBLE WARM UP ON WEDNESDAY
AND THURSDAY...ANOTHER BIG SURGE OF ARCTIC AIR LOOKS POISED TO DROP
DOWN INTO THE NORTH CENTRAL U.S. HEADING INTO THE FIRST OFFICIAL
WEEKEND OF WINTER.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z FRIDAY MORNING)
ISSUED AT 534 AM CST THU DEC 12 2013
VFR CONDITIONS ARE EXPECTED THROUGH THE TAF PERIOD. CIRRUS WILL
SPREAD ACROSS THE REGION TODAY AHEAD OF A WEAK STORM SYSTEM
PUSHING SOUTHEAST FROM THE NORTHERN PLAINS. THE SYSTEM WILL SLIDE
OVER NORTHERN WISCONSIN LATE THIS AFTERNOON INTO TONIGHT BUT WILL
DO LITTLE MORE THAN DROP CEILINGS INTO THE 8 TO 10 KFT RANGE AT
BOTH KRST AND KSLE. WINDS WILL BE OUT OF THE WEST/SOUTHWEST TODAY
AT AROUND 8 KTS...THEN BECOMING LIGHT LATE THIS AFTERNOON INTO
THIS EVENING. WINDS WILL SWITCH TO THE EAST EARLY FRIDAY MORNING
AS A SYSTEM DEVELOPS OVER THE CENTRAL PLAINS AND EDGES EAST INTO
THE MID MISSISSIPPI RIVER VALLEY.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
SHORT TERM...AJ
LONG TERM...AJ
AVIATION...WETENKAMP
AREA FORECAST DISCUSSION
NWS DENVER/BOULDER CO
1221 PM MST THU DEC 12 2013
.UPDATE...
&&
.SHORT TERM...WILL ISSUE ANOTHER AMENDMENT TO TODAY`S FORECAST
TO ACCOUNT TO EVEN HIGHER THAN EXEPCTED MAXIMUM
TEMPERATURES...PARTICULARLY FOR FOOTHILL AND I-25 URBAN CORRIDOR
ZONES. TEMPERATURES CONTINUE TO RISE WITH MANY LOCALES IN AND NEAR
THE FOOTHILLS ALREADY IN THE MID TO UPPER 50S. SO WILL NUDGE UP
MAX TEMPS ANOTHER 2-4F IN THESE AREAS.
.PREV DISCUSSION... /ISSUED 1045 AM MST THU DEC 12 2013/
UPDATE...
SHORT TERM...FIRST PERIOD TEMPERATURES MAIN REASON FOR ADJUSTMENT
TO CURRENT FORECAST PACKAGE. MORNING TEMPERATURES HAVE BEEN
ESPECIALLY BALMY IN THE FRONT RANGE FOOTHILLS AND ARE VISIBLY
EVIDENT ON IR SATELLITE AND OF COURSE ON OBS. MID-MORNING READINGS
AT MANY FOOTHILL LOCALES ALREADY IN THE MID TO UPPER 40S. WHILE
TEMPS AT THE BASE OF THE FOOTHILLS STILL IN THE UPPER 20S AND LOWER
30S. TEMPERATURES WERE ALSO ZOOMING UP ON THE HIGHER TERRAIN OF THE
PALMER DIVIDE WHERE READINGS IN THE MID TO UPPER 40S. EAST SIDE OF
THE DENVER METRO AREA ALSO BENEFITING FROM DOWNSLOPE WARMING WHERE
SIMILAR READINGS EXIT. HAVE RAISED MAX TEMPS BY 4-7 DEGS F ON AND
ALONG THE FRONT RANGE FOOTHILLS TO ACCOUNT FOR RAPID WARMUP THIS
MORNING. OTHERWISE GENERALLY CLEAR SKIES AND GENTLE BREEZES ON TAP
FOR THE REMAINDER OF TODAY. ALTHOUGH HIGHER FOOTHILL AREAS COULD SEE
GUSTY WESTERLY WINDS DEVELOPING LATER THIS AFTERNOON.
&&
.AVIATION...VFR CONDITIONS FOR THE NEXT 24 HOURS. SOUTH-SOUTHEAST
WINDS OF 7-13KTS EXPECTED MOST OF THE TODAY FOR TERMINALS ON THE
SOUTH AND EAST SIDES OF THE DENVER METRO AREA...AND WEST-NORTHWEST
AT 5-9KTS ON THE WEST SIDE. OTHERWISE CONTINUED DRY WITH ABOVE
AVERAGE TEMPERATURES.
.PREV DISCUSSION... /ISSUED 313 AM MST THU DEC 12 2013/
SHORT TERM...DRY WNW FLOW ALOFT WILL BE OVER THE AREA TODAY THRU
TONIGHT. MAIN CONCERN FOR TODAY WILL BE HIGHS OVER NERN CO. SNOW
COVER STILL EXISTS OVER ERN LARIMER INTO CENTRAL WELD AND OVER THE
PALMER DIVIDE. OVERALL LOW LEVEL WINDS FIELDS WILL BE LIGHT SO
THERE WILL NOT BE MUCH OF A DOWNSLOPE COMPONENT OVER THE PLAINS
ALTHOUGH THERE WILL BE PLENTY OF SUN. SO THE BIG QUESTION IS WILL
THE LOW LEVEL INVERSIONS BE BKN OR NOT AS THERE WILL BE 5 TO 6
DEGREES C OF WARMING JUST ABV THE SFC.
THE NAM AND GFS PRETTY MUCH SHOW NO INVERSIONS ANYWHERE WITH
READINGS IN THE 40S ACROSS THE PLAINS WITH HIGHS IN THE LOWER 50S
AROUND DENVER. MEANWHILE THE HRRR AND TO SOME EXTENT THE RAP SHOW
INVERSIONS NOT BREAKING IN THE SNOW COVERED AREAS AS READINGS HOLD
IN THE 30S. IN ADDITION THE HRRR SHOWS QUITE A CONTRAST OVER THE
DENVER METRO AREA WITH READINGS NEAR 50 OVER THE SRN SUBURBS WHILE
IN NRN AREAS HIGHS STAY IN THE 35 TO 40 RANGE. THERE MAY END UP
BEING A WK DENVER CYCLONE WHICH ALLOWS FOR NLY SFC FLOW OVER THE NRN
SUBURBS THAT ALLOWS FOR SOME OF THE COOLER SFC TEMPS OVER WELD
COUNTY TO MOVE SOUTH SO CAN NOT COMPLETELY IGNORE WHAT THE HRRR
SHOWS. FOR NOW WILL KEEP READINGS COOLER THAN GUIDANCE FROM NORTH
OF DENVER TO FORT COLLINS TO GREELEY AND TOWARDS LIMON. FURTHER
SOUTH WILL HAVE HIGHS IN THE 45 TO 50 DEGREE RANGE AND OVER THE
FAR NERN CORNER.
LONG TERM...MODELS HAVE A COUPLE WEAK UPPER TROUGHS TO MOVE
ACROSS THE CWA. BOTH WITH SLIGHTLY COOLER AIMASSES. THE FIRST ON
FRIDAY MORNING...THEN ANOTHER FRIDAY NIGHT LATE/EARLY SATURDAY
MORNING. BY SATURDAY AFTERNOON AND NIGHT...FAIRLY STRONG
NORTHERLY FLOW ALOFT IS PROGGED. THERE IS WEAK UPWARD SYNOPTIC
SCALE ENERGY PROGGED FOR THE CWA FRIDAY INTO FRIDAY NIGHT...THEN
ALL DOWNWARD MOTION SATURDAY AND SATURDAY NIGHT. THE LOW LEVEL
WINDS ARE PROGGED TO GO TO UPSLOPE FRIDAY AFTERNOON AND EVENING.
MORE NORMAL DIURNAL PATTERNS ARE PROGGED FOR SATURDAY. FOR
MOISTURE...IN INCREASES SOMEWHAT FRIDAY...WITH THE BEST FRIDAY
EVENING OVER THE MOUNTAINS. MOISTURE DRIES OUT LATE FRIDAY
NIGHT...AND THERE ISN`T MUCH SATURDAY OR SATURDAY NIGHT. THE QPF
FIELDS SHOW A TINY AMOUNT OF MEASURABLE SNOWFALL OVER THE HIGH
MOUNTAINS FRIDAY EVENING...BUT ONLY ON THE GFS. WILL KEEP POPS IN
FRIDAY NIGHT...MOSTLY OVER JUST THE HIGH MOUNTAINS. FOR
TEMPERATURES...FRIDAY`S HIGHS ARE 2-4 C COOLER THAN TODAY`S.
SATURDAY`S ARE SIMILAR TO FRIDAY`S. FOR THE LATER DAYS...SUNDAY
THROUGH WEDNESDAY...MODELS KEEP MODERATE NORTHWESTERLY FLOW ALOFT
FOR THE CWA SUNDAY AND MONDAY. ON TUESDAY AND WEDNESDAY IT IS
WEST-NORTHWESTERLY AND INCREASES IN SPEED....ESPECIALLY ON THE
GFS. THE GFS BRINGS A JET MAXIMUM OVER THE CWA...THE ECMWF KEEPS
IT WELL NORTH AND NORTHEAST. MOISTURE IS LACKING ALL FOUR DAYS.
AVIATION...VFR TODAY AND TONIGHT. WINDS WILL BE LIGHT SLY THIS
MORNING AND MORE SSW AFTER SUNRISE. FOR THIS AFTN THERE MAY BE A
WK DENVER CYCLONE WITH WINDS BECOME MORE NNE AFTER 20Z. BY 00Z
WINDS MAY BECOME MORE ESE AND THEN BACK TO DRAINAGE BY 02Z.
&&
.BOU WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...BAKER
LONG TERM....RPK
AREA FORECAST DISCUSSION...CORRECTION
NWS DENVER/BOULDER CO
1045 AM MST THU DEC 12 2013
.UPDATE...
&&
.SHORT TERM...FIRST PERIOD TEMPERATURES MAIN REASON FOR ADJUSTMENT
TO CURRENT FORECAST PACKAGE. MORNING TEMPERATURES HAVE BEEN
ESPECIALLY BALMY IN THE FRONT RANGE FOOTHILLS AND ARE VISIBLY
EVIDENT ON IR SATELLITE AND OF COURSE ON OBS. MID-MORNING READINGS
AT MANY FOOTHILL LOCALES ALREADY IN THE MID TO UPPER 40S. WHILE
TEMPS AT THE BASE OF THE FOOTHILLS STILL IN THE UPPER 20S AND LOWER
30S. TEMPERATURES WERE ALSO ZOOMING UP ON THE HIGHER TERRAIN OF THE
PALMER DIVIDE WHERE READINGS IN THE MID TO UPPER 40S. EAST SIDE OF
THE DENVER METRO AREA ALSO BENEFITING FROM DOWNSLOPE WARMING WHERE
SIMILAR READINGS EXIT. HAVE RAISED MAX TEMPS BY 4-7 DEGS F ON AND
ALONG THE FRONT RANGE FOOTHILLS TO ACCOUNT FOR RAPID WARMUP THIS
MORNING. OTHERWISE GENERALLY CLEAR SKIES AND GENTLE BREEZES ON TAP
FOR THE REMAINDER OF TODAY. ALTHOUGH HIGHER FOOTHILL AREAS COULD SEE
GUSTY WESTERLY WINDS DEVELOPING LATER THIS AFTERNOON.
.AVIATION...VFR CONDITIONS FOR THE NEXT 24 HOURS. SOUTH-SOUTHEAST
WINDS OF 7-13KTS EXPECTED MOST OF THE TODAY FOR TERMINALS ON THE
SOUTH AND EAST SIDES OF THE DENVER METRO AREA...AND WEST-NORTHWEST
AT 5-9KTS ON THE WEST SIDE. OTHERWISE CONTINUED DRY WITH ABOVE
AVERAGE TEMPERATURES.
&&
.PREV DISCUSSION... /ISSUED 313 AM MST THU DEC 12 2013/
SHORT TERM...DRY WNW FLOW ALOFT WILL BE OVER THE AREA TODAY THRU
TONIGHT. MAIN CONCERN FOR TODAY WILL BE HIGHS OVER NERN CO. SNOW
COVER STILL EXISTS OVER ERN LARIMER INTO CENTRAL WELD AND OVER THE
PALMER DIVIDE. OVERALL LOW LEVEL WINDS FIELDS WILL BE LIGHT SO
THERE WILL NOT BE MUCH OF A DOWNSLOPE COMPONENT OVER THE PLAINS
ALTHOUGH THERE WILL BE PLENTY OF SUN. SO THE BIG QUESTION IS WILL
THE LOW LEVEL INVERSIONS BE BKN OR NOT AS THERE WILL BE 5 TO 6
DEGREES C OF WARMING JUST ABV THE SFC.
THE NAM AND GFS PRETTY MUCH SHOW NO INVERSIONS ANYWHERE WITH
READINGS IN THE 40S ACROSS THE PLAINS WITH HIGHS IN THE LOWER 50S
AROUND DENVER. MEANWHILE THE HRRR AND TO SOME EXTENT THE RAP SHOW
INVERSIONS NOT BREAKING IN THE SNOW COVERED AREAS AS READINGS HOLD
IN THE 30S. IN ADDITION THE HRRR SHOWS QUITE A CONTRAST OVER THE
DENVER METRO AREA WITH READINGS NEAR 50 OVER THE SRN SUBURBS WHILE
IN NRN AREAS HIGHS STAY IN THE 35 TO 40 RANGE. THERE MAY END UP
BEING A WK DENVER CYCLONE WHICH ALLOWS FOR NLY SFC FLOW OVER THE NRN
SUBURBS THAT ALLOWS FOR SOME OF THE COOLER SFC TEMPS OVER WELD
COUNTY TO MOVE SOUTH SO CAN NOT COMPLETELY IGNORE WHAT THE HRRR
SHOWS. FOR NOW WILL KEEP READINGS COOLER THAN GUIDANCE FROM NORTH
OF DENVER TO FORT COLLINS TO GREELEY AND TOWARDS LIMON. FURTHER
SOUTH WILL HAVE HIGHS IN THE 45 TO 50 DEGREE RANGE AND OVER THE
FAR NERN CORNER.
LONG TERM...MODELS HAVE A COUPLE WEAK UPPER TROUGHS TO MOVE
ACROSS THE CWA. BOTH WITH SLIGHTLY COOLER AIMASSES. THE FIRST ON
FRIDAY MORNING...THEN ANOTHER FRIDAY NIGHT LATE/EARLY SATURDAY
MORNING. BY SATURDAY AFTERNOON AND NIGHT...FAIRLY STRONG
NORTHERLY FLOW ALOFT IS PROGGED. THERE IS WEAK UPWARD SYNOPTIC
SCALE ENERGY PROGGED FOR THE CWA FRIDAY INTO FRIDAY NIGHT...THEN
ALL DOWNWARD MOTION SATURDAY AND SATURDAY NIGHT. THE LOW LEVEL
WINDS ARE PROGGED TO GO TO UPSLOPE FRIDAY AFTERNOON AND EVENING.
MORE NORMAL DIURNAL PATTERNS ARE PROGGED FOR SATURDAY. FOR
MOISTURE...IN INCREASES SOMEWHAT FRIDAY...WITH THE BEST FRIDAY
EVENING OVER THE MOUNTAINS. MOISTURE DRIES OUT LATE FRIDAY
NIGHT...AND THERE ISN`T MUCH SATURDAY OR SATURDAY NIGHT. THE QPF
FIELDS SHOW A TINY AMOUNT OF MEASURABLE SNOWFALL OVER THE HIGH
MOUNTAINS FRIDAY EVENING...BUT ONLY ON THE GFS. WILL KEEP POPS IN
FRIDAY NIGHT...MOSTLY OVER JUST THE HIGH MOUNTAINS. FOR
TEMPERATURES...FRIDAY`S HIGHS ARE 2-4 C COOLER THAN TODAY`S.
SATURDAY`S ARE SIMILAR TO FRIDAY`S. FOR THE LATER DAYS...SUNDAY
THROUGH WEDNESDAY...MODELS KEEP MODERATE NORTHWESTERLY FLOW ALOFT
FOR THE CWA SUNDAY AND MONDAY. ON TUESDAY AND WEDNESDAY IT IS
WEST-NORTHWESTERLY AND INCREASES IN SPEED....ESPECIALLY ON THE
GFS. THE GFS BRINGS A JET MAXIMUM OVER THE CWA...THE ECMWF KEEPS
IT WELL NORTH AND NORTHEAST. MOISTURE IS LACKING ALL FOUR DAYS.
AVIATION...VFR TODAY AND TONIGHT. WINDS WILL BE LIGHT SLY THIS
MORNING AND MORE SSW AFTER SUNRISE. FOR THIS AFTN THERE MAY BE A
WK DENVER CYCLONE WITH WINDS BECOME MORE NNE AFTER 20Z. BY 00Z
WINDS MAY BECOME MORE ESE AND THEN BACK TO DRAINAGE BY 02Z.
&&
.BOU WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...BAKER/RPK
LONG TERM....RPK
AVIATION...BAKER/RPK
AREA FORECAST DISCUSSION
NWS NORTHERN INDIANA
327 PM EST THU DEC 12 2013
.SYNOPSIS...
ISSUED AT 330 PM EST THU DEC 12 2013
HIGH PRESSURE WILL BE OVER THE REGION TONIGHT BUT TEMPERATURES
WILL NOT BE AS COLD AS LAST NIGHT. LOWS WILL STILL DROP INTO THE
LOWER AND MIDDLE TEENS...WITH A FEW SINGLE DIGITS POSSIBLE IN
RURAL AREAS. CLOUDS WILL INCREASE FRIDAY AHEAD OF A STRONG LOW
PRESSURE SYSTEM WHICH WILL BRING ACCUMULATING SNOW TO THE REGION
FRIDAY NIGHT AND SATURDAY. CURRENT INDICATIONS ARE THAT
ACCUMULATIONS BETWEEN 2 AND 5 INCHES WILL BE LIKELY.
&&
.SHORT TERM...(THIS EVENING THROUGH FRIDAY)
ISSUED AT 323 PM EST THU DEC 12 2013
FEW CONCERNS THROUGH THE SHORT TERM PERIOD AS SIGNIFICANT WEATHER
AHEAD OF NEXT SYSTEM WILL HOLD OFF UNTIL FRIDAY NIGHT.
SATELLITE SHOWING MID AND HIGH CLOUDS EXITING SOUTHERN AREAS THIS
AFTERNOON WHILE THERMAL TROUGH SAGGING ACROSS LAKE MICHIGAN WAS
AIDING IN STRATOCU DEVELOPMENT ACROSS BERRIEN AND CASS COUNTIES IN
MICHIGAN. THESE LOW CLOUDS AND ANY LAKE EFFECT SNOW SHOWERS WILL BE
MAIN CHALLENGE TONIGHT. SYNOPTIC SCALE THERMAL TROUGH ALREADY MOVING
EAST BUT LAKE INDUCED TROUGHINESS AND THERMAL DISPARITY PROGGED TO
ONLY SLOWLY WARM OVERNIGHT. SATELLITE ALREADY SHOWING LAKE CLOUDS
INTO NORTHERN BERRIEN COUNTY DESPITE WARM AIR ADVECTION. HIRES
GUIDANCE SUGGEST TRAJECTORIES AND WEAK LAKE AGGREGATE TROUGH MAY
ALLOW CLOUDS TO STREAM ACROSS MICHIGAN COUNTIES THIS EVENING AND
INTO OVERNIGHT HOURS. PREVIOUS SKY COVER GRIDS HAD THIS TREND
HANDLED WELL AND GENERALLY STAYED WITH SIMILAR IDEA. LIGHT SNOW
SHOWERS ALREADY NEAR OR INTO EXTREME NORTHERN TIP OF BERRIEN COUNTY
SO WILL CARRY SCT FLURRIES OR LIGHT SNOW SHOWERS THROUGH THE EVENING
UNTIL WARMER AIR ARRIVES AND FLOW WEAKENS WHICH COULD LEAD TO WEAK
MESOLOW FORMATION OVER BOWL REGION OF LAKE. LITTLE OR NO
ACCUMULATION EXPECTED GIVEN SHALLOW MOISTURE DEPTH IN OUR AREA.
OTHERWISE EXPECT MOSTLY CLEAR SKIES TO START THE EVENING WITH SOME
MID AND HIGH CLOUDS INCREASING LATE.
NAM MODEL SOUNDINGS QUITE BULLISH ON LOW LEVEL MOISTURE AND STRATUS
DEVELOPMENT FRIDAY MORNING. NAM12 HAS BEEN RATHER
AGGRESSIVE WITH THIS IDEA THIS WINTER WITH SEVERAL INSTANCES SHOWING
THIS WITH LITTLE TO NO DEVELOPMENT. LATEST HRRR GIVES SOME CREDENCE
TO THIS SOLUTION IN THE NORTH NEAR WEAK SURFACE BOUNDARY WHERE WINDS
BECOME LIGHT. HAVE SLOWLY INCREASED CLOUDS ACROSS THE NORTH
AND NORTHWEST WITH POTENTIAL FOR SOME MID AND HIGH CLOUDS AS WELL.
THIS SHOULD KEEP TEMPS FROM FALLING TOO MUCH OVERNIGHT WITH WARM AIR
ADVECTION WELL UNDERWAY. LOOKING FOR LOWS IN THE 10 TO 15 DEGREE
RANGE LATE EVENING WITH STEADY OR EVEN SLOWLY RISING TEMPS LATE WITH
ANY CLOUD COVER DEVELOPMENT.
COL AREA ASSOCIATED WITH WEAK BOUNDARY WILL LIE ACROSS NW FORECAST
AREA FRIDAY WITH GENERALLY LIGHT WINDS. CLOUD COVER REMAINS TRICKY
DEPENDING ON HOW MUCH SATURATION OCCURS NEAR BOUNDARY WITH INVERSION
ALOFT COURTESY OF WARM AIR ADVECTION. HIGHS WILL REACH MID TO UPPER
20S MOST AREAS WITH LOW 30S POSSIBLE FAR SOUTHWEST AHEAD OF NEXT
STRONG SHORT WAVE. BULK OF PCPN WILL HOLD OFF UNTIL FRIDAY EVENING
BUT DID ALLOW A SLIGHT CHANCE TO RESIDE FAR SOUTHWEST AFTER 21Z WITH
PROXIMITY OF INCREASING MOISTURE AND ISENTROPIC LIFT.
&&
.LONG TERM...(FRIDAY NIGHT THROUGH THURSDAY)
ISSUED AT 323 PM EST THU DEC 12 2013
...ACCUMULATING SNOWFALL FRIDAY NIGHT-SATURDAY...
PATTERN IS STILL SUPPORTIVE OF FAVORABLE SYNOPTIC SCALE SNOW EVENT
FOR THE REGION BEGINNING LATE FRIDAY NIGHT AND CONTINUING INTO THE
DAY SATURDAY.
NORTHERN STREAM FLOW WILL KEEP THE BOUNDARY LAYER COLD AIR IN PLACE
AND DEEP ENOUGH TO FAVOR ALL SNOW FOR THE EVENT. THE CHALLENGE WILL
BE TIMING THE PHASING OF THE SOUTHERN STREAM AND NORTHERN STREAM
SHORTWAVES ACROSS THE GREAT LAKES.
12Z RUNS ARE GENERALLY CONSISTENT WITH THE SURFACE LOW DEEPENING IN
THE PANHANDLE REGION DURING THE DAY FRIDAY. CONTINUED DEEPENING AND
OF THE SURFACE LOW OVER THE SORUTHERN PLAINS AND LOWER MISSISSIPPI
RIVER VALLEY DURING THE EVENING FRIDAY INTO SATURDAY WILL USHER IN
COPIOUS MOISTURE AND EXPECT TO SEE A PRONOUNCED WARM LAYER SPREADING
NORTHWARD. THIS WILL FAVOR A MORE DENSE AND WET SNOW ACROSS THE
SOUTH.
TIMING AND PHASING OF THE SOUTHERN AND NORTHERN STREAM WILL
CRITICALLY AFFECT THE DURARTION OF THE SNOW AND EXPECT THAT THERE
WILL BE A RAPID CUTOFF OF PRECIPITATION EARLY SATURDAY.
SNOWFALL WILL BE HEAVIEST AND WETTER SOUTH OF THE CWFA AND DRIER
NORTH. REGARDLESS EXPECT TO SEE UPWARDS OF 5 INCHES ACROSS MOST OF
THE AREA.
AS THE SYNOPTIC DRIVEN SNOW ENDS...LAKE EFFECT SHOULD CONTINUE IN
LAPORTE...ST. JOSEPH...BERRIEN AND CASS COUNTIES FOR AN ADDITIONAL 2
TO 4 INCHES BY SATURDAY NIGHT EARLY SUNDAY MORNING.
COLDER AND DRIER AIR WILL SETTLE ACROSS THE PLAINS SUNDAY AND WITH
NEW SNOW AND SOME CLEARING...TEMPERATURES SHOULD BOTTOM OUT AGAIN
SUNDAY NIGHT/MONDAY MORNING. WILL BE MAKING SOME DOWNWARD
ADJUSTMENTS TO THE TEMPERATURES FOR SUN/MON PERIOD.
NEXT CLIPPER SYSTEM FORMS IN THE GREAT LAKES REGION MONNDAY/MONDAY
NIGHT/TUESDAY AND THIS WILL BRING AN INCREASE OF CLOUDS AND LAKE
EFFECT TO THE AREA. TIMING AND DURATION OF SNOWFALL IS TOO FAR OUT
TO MAKE DEFINITIVE AMOUNT FORECASTS...BUT IT WILL ADD TO THE SNOW
ALREADY ON THE GROUND. AS THAT SYSTEM EXITS...THE COLD AIR RETURNS
IN ITS WAKE. STARTING TO SEE A DECENT SNOW PACK OVER THE NRN
PLAINS...ADDING TO THE DOUBT THAT ANY SIZABLE WARMUP IS COMING OUR
WAY.
NEXT STORY ON THE HORIZON...ECMWF PREDICTION OF DEEP AND EXPLOSIVE
CYCLOGENSIS ACROSS THE NORTHERN AND CENTRAL PLAINS WEDNESDAY NIGHT
INTO THURSDAY. THERE ARE HINTS IN THE OTHER LONG RANGE MODELS OF A
WAVE EJECTING THROUGH THE ROCKIES. THIS WILL HAVE TO BE WATCHED AS
THE PATTERN EVOLVES.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z FRIDAY AFTERNOON)
ISSUED AT 1247 PM EST THU DEC 12 2013
VFR CONDITIONS TO START THE PERIOD WITH SOME UNCERTAINTY
REGARDING CIGS TONIGHT AND FRIDAY MORNING. MID AND HIGH CLOUDS
GRADUALLY MOVING OFF TO SOUTHEAST WITH PARTIAL CLEARING OCCURING
AT TAF SITES EARLY THIS AFTERNOON. LAKE CLOUDS SEEN ON SATELLITE
DROPPING SOUTH TOWARD KBEH AT 1730Z WITHIN THERMAL TROUGH. THIS
TROUGH NOT PROGGED TO REACH KSBN AS IT SLOWLY MIGRATES EAST.
HOWEVER...LOW LEVEL WIND FIELD BECOMES WNW FOR A PERIOD WHICH MAY
ALLOW CLOUDS TO DRIFT TOWARD KSBN. MODEL SOUNDINGS ALSO SHOWING
INCREASING LOW LEVEL MOISTURE AROUND 00Z WITH THESE TRAJECTORIES.
FOR NOW DO NOT HAVE ENOUGH CONFIDENCE FOR MVFR OR IFR CONDITIONS
AT KSBN OVERNIGHT SO STAYED VFR WITH INTRODUCTION OF SOME SCT015
CLOUDS. WEAK FRONTAL BOUNDARY TO SAG NEAR KSBN FRI AM WITH WEAK
WINDS AND MOISTURE TRAPPED BENEATH INVERSION WITH WARM AIR
ADVECTION ALOFT. THIS LEADS TO A LITTLE HIGHER CONFIDENCE IN MVFR
CIGS DEVELOPING DURING THE DAY ALONG WITH MODEL GUIDANCE SO ADDED
MVFR CONDITIONS. KFWA TO REMAIN VFR THROUGH THIS PERIOD WITH
DETERIORATING CONDITIONS EXPECTED LATER FRIDAY AND ESPECIALLY
FRIDAY NIGHT ALL AREAS WITH SNOW DEVELOPING.
&&
.IWX WATCHES/WARNINGS/ADVISORIES...
IN...NONE.
MI...NONE.
OH...NONE.
LM...SMALL CRAFT ADVISORY UNTIL 7 PM EST THIS EVENING FOR LMZ043-046.
&&
$$
SYNOPSIS...LASHLEY
SHORT TERM...LASHLEY
LONG TERM...LEWIS
AVIATION...LASHLEY
VISIT US AT WWW.WEATHER.GOV/IWX (ALL LOWER CASE)
FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
WWW.FACEBOOK.COM/US.NATIONALWEATHERSERVICE.NORTHERNIN.GOV
WWW.TWITTER.COM/NWSIWX
WWW.YOUTUBE.COM/NWSNORTHERNINDIANA
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
421 PM EST THU DEC 12 2013
.SHORT TERM...(THIS EVENING THROUGH FRIDAY)
ISSUED AT 419 PM EST THU DEC 12 2013
WV IMAGERY AND RUC ANALYSIS INDICATED A BROAD MID/UPPER LEVEL TROUGH
ACROSS ERN NOAM RESULTING IN NW FLOW THROUGH THE NRN GREAT LAKES. A
SHORTWAVE TROUGH WAS MOVING THROUGH NW ONTARIO DRAGGING A COLD FRONT
THROUGH WRN LAKE SUPERIOR. FARTHER UPSTREAM...A WEAK CLIPPER SHRTWV
WAS MOVING FROM SRN SASK INTO THE NRN PLAINS. LES BANDS ALIGNED WITH
WNW FLOW THROUGH ERN LAKE SUPERIOR INTO NE ALGER AND NRN LUCE
COUNTIES HAD DIMINISHED SLIGHTLY AND BECOME MORE CELLULAR THIS
AFTERNOON WITH WEAKENING LOW LEVEL CONV FROM LAND BREEZE COMPONENT.
EXPECT THAT THE LOW LEVEL WINDS WILL DIMINISH AND VEER FROM WNW TO
NRLY. THIS SHOULD PUSH THE MORE SIGNIFICANT LES THROUGH MUCH OF THE
ERN CWA FROM ALGER COUNTY EASTWARD AS A STRENGTHENING LAND BREEZE
SHOULD KEEP MOST OF THE SNOW EAST OF MARQUETTE. EVEN WITH THE
SHIFTING POSITION OF THE LES BANDS...FAVORABLE SNOW GROWTH WITH THE
DGZ IN THE 1K-4K CONVECTIVE LAYER PUSHING SLR VALUES ABOVE 25/1 AND
SHOULD SUPPORT ADVISORY SNOWFALL AMOUNTS IN THE 3 TO 6 INCH RANGE.
OVER THE WEST...THE SHORTER FETCH...ACYC FLOW AND LOWER INVERSION
HEIGHTS FROM 3K-4K FT...WILL KEEP SNOWFALL AMOUNTS IN THE 1 TO 3
INCH RANGE.
FROM LATE TONIGHT INTO EARLY FRI...THE SASK SHRTWV AND WEAK UPPER
LEVEL DIV WITH THE RIGHT ENTRANCE OF A 140 KT 250-300 MB JET WITH
ASSOCIATED 800-600 MB FGEN MAY SUPPORT A BAND OF LIGHT SNOW.
HOWEVER...MODELS SUGGEST THAT THE BEST CHANCE OF LIGHT SNOW WITH
THESE FEATURES WILL REMAIN OVER WI. SO...ONLY CHANCE POPS WITH
ACCUMULATIONS LESS THAN A HALF INCH WERE INCLUDED.
WINDS WILL CONTINUE TO VEER FRIDAY AS ARCTIC HIGH PRES FROM
SASK/MANITOBA INTO NRN ONTARIO BUILDS INTO THE NRN LAKES. WITH WINDS
SHIFTING FROM N TO NNE THE MOST FAVORABLE LOW LEVEL CONV WILL SHIFT
FROM THE NE CWA INTO MARQUETTE COUNTY. WHILE SNOW GROWTH WILL REMAIN
FAVORABLE...INVERSION HEIGHT REMAINING NEAR 5K-6K FT WITH MAINLY
ACYC UPSTREAM FLOW MAY LIMIT LES INTENSITY AND SNOWFALL AMOUNTS
BELOW ADVY LEVELS. GENERALLY 1 TO 3 INCHES ARE EXPECTED WITH THE
GREATEST AMOUNTS IN FAR WRN ALGER COUNTY INTO ERN MARQUETTE COUNTY.
.LONG TERM...(FRIDAY NIGHT THROUGH THURSDAY)
ISSUED AT 419 PM EST THU DEC 12 2013
MODELS TODAY CONTINUE TO INDICATE AN OVERALL COLD PATTERN THRU THE
LONG TERM PORTION OF THE FCST. HOWEVER...WITH CURRENT DEEP EXPANSIVE
POLAR VORTEX CENTERED AROUND HUDSON BAY STILL FCST TO WEAKEN AND
RETREAT N THRU AT LEAST THE MIDDLE OF NEXT WEEK...THE COLD WILL EASE
SOME. A VAST SUPPLY OF COLD AIR WILL REMAIN ACROSS CANADA...SO ANY
SHORTWAVE TRACKING ALONG IN THE RELAXING NW FLOW PATTERN WILL BE
ABLE TO TUG COLDER AIR INTO THE UPPER LAKES. FOR THIS REASON...
MEDIUM RANGE GUIDANCE FOR SEVERAL DAYS HAS BEEN PROGRESSIVELY SLOWER
TO BRING WARMING INTO THE UPPER LAKES AND HAS ALSO BEEN MORE
TEMPERED WITH THE WARMING. AROUND THE MIDDLE OF NEXT WEEK THERE WILL
BE A TEMPORARY SHIFT IN THE PATTERN TOWARD A DEEPENING TROF OVER THE
WRN CONUS AND DOWNSTREAM BUILDING RIDGE OVER THE SE CONUS/WRN
ATLANTIC. THUS THE MIDWEEK PERIOD WILL OFFER THE BEST CHANCE OF A
WARMUP. HOW MUCH WARMING OCCURS WILL DEPEND ON THE AMPLITUDE AND
LONGITUDE OF THE TROF/RIDGE PATTERN. LATEST MODEL TRENDS POINT
TOWARD AN EWD SHIFT IN THE TROF/RIDGE PATTERN WHICH WILL LIMIT
WARMING FOR THE UPPER LAKES. IN ANY CASE...WARMING WILL ONLY BE
BRIEF AS LONGER RANGE GUIDANCE CONTINUES TO POINT TOWARD
REINTENSIFYING ARCTIC AIR ACROSS WRN/NRN CANADA DUMPING BACK INTO
THE AREA SOMETIME AROUND THE WEEKEND BEFORE CHRISTMAS. OUTSIDE OF
AREAS AFFECTED BY LES/LAKE ENHANCEMENT...THERE WON`T BE MUCH MORE
THAN SOME -SN AT TIMES DURING THE LONG TERM. THE RESURGENCE OF
ARCTIC AIR S INTO THE CONUS LATE NEXT WEEK/WEEKEND COULD OFFER THE
POTENTIAL FOR SOMETHING MORE SUBSTANTIAL IN TERMS OF WIDESPREAD
SNOWFALL.
BEGINNING FRI NIGHT...WINDS WILL CONTINUE VEERING TO THE E THEN
SE FRI NIGHT/SAT MORNING AS SFC HIGH PRES CENTER PASSES JUST N OF
LAKE SUPERIOR AND NEXT CLIPPER SHORTWAVE APPROACHES FROM THE NW. LES
THAT WILL BE OCCURRING MAINLY INTO NCNTRL UPPER MI THU AFTN WILL
SLOWLY SHIFT OUT OF NCNTRL UPPER MI AND THEN CROSS THE KEWEENAW
PENINSULA FOR A TIME LATE FRI NIGHT/SAT MORNING. DGZ WILL BE WELL
CENTERED IN THE CONVECTIVE LAYER...SO A FEW INCHES OF FLUFFY SNOW
ARE POSSIBLE IN THIS AREA OF LES THAT WILL BE SHIFTING WITH THE
WINDS. ALSO...WITH WINDS VEERING OVER NRN LAKE MI...LES OFF LAKE MI
WILL LIKELY MOVE INTO MENOMINEE COUNTY AND POSSIBLY DELTA COUNTY...
LEADING TO SOME FLUFFY SNOW ACCUMULATIONS LATE FRI NIGHT/SAT
MORNING.
ATTENTION THEN TURNS TO NEXT CLIPPER SHORTWAVE DROPPING THRU THE
UPPER GREAT LAKES SAT NIGHT/SUN. -SN ASSOCIATED WITH FEATURE SHOULD
SPREAD INTO THE AREA SAT AFTN/EVENING...AND IT LOOKS LIKE THERE WILL
BE A PERIOD OF LAKE ENHANCEMENT OFF LAKE MI IN SOUTHERLY FLOW...
LEADING TO A POTENTIAL ADVY EVENT. A BRIEF SHOT OF ARCTIC AIR
FOLLOWING SYSTEM WILL PROBABLY RESULT IN A SHORT DURATION PERIOD OF
MDT TO POSSIBLY HVY LAKE ENHANCED SNOW FOR NORTHWEST AND NORTHEAST
UPPER MI LATE SAT NIGHT/EARLY SUNDAY AS WIND SHIFTS NW. SINCE DEEP
LAYER FORCING WITH SHORTWAVE IS FAIRLY IMPRESSIVE...WILL NEED TO
WATCH FOR LOCALLY HVY LAKE ENHANCED SNOW OFF LAKE MI AHEAD OF WAVE
AND OFF LAKE SUPERIOR AS THE WAVE PASSES. AS WINDS VEER AROUND TO
THE N OR NE WITH SFC HIGH PRES PASSING ACROSS NRN ONTARIO...LIGHTER
LES WILL AGAIN SHIFT TO AFFECT MORE OF NRN UPPER MI SUN
AFTN/EVENING.
OVER THE LAST FEW DAYS...UNCERTAINTY FOR THE EARLY AND MIDDLE PARTS
OF NEXT WEEK HAS BEEN HIGH WITH REGARD TO TIMING/STRENGTH/TRACK OF
SEVERAL SHORTWAVES IN WNW FLOW. IT APPEARS THERE MAY BE A COUPLE OF
PERIODS OF WIDESPREAD -SN (CONFIDENCE HIGHEST FOR -SN ON MON) AS
WELL AS LAKE ENHANCEMENT OFF LAKE MICHIGAN AND LAKE SUPERIOR
DEPENDING ON WIND DIRECTION IMMEDIATELY PRIOR TO AND AFTER PASSAGE
OF THE WAVES. GIVEN THE SPREAD OF SOLUTIONS IN RECENT DAYS...
CONFIDENCE IN SNOW AND TEMP FCSTS FOR MON-WED ESPECIALLY TUE/WED
WILL BE LOW UNTIL THAT PART OF THE FCST MOVES CLOSER TO THE SHORT
TERM.
THERE ARE SOME INDICATIONS THAT A SOMEWHAT MORE MEANINGFUL LOW PRES
WAVE MAY MOVE TOWARD THE GREAT LAKES THU/FRI AS THE WRN TROF
DEVELOPS/DEEPENS AND BEGINS TO SHIFT E.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z FRIDAY AFTERNOON)
ISSUED AT 108 PM EST THU DEC 12 2013
CMX...WNW LOW LEVEL FLOW WILL CONTINUE TO BRING LIGHT TO PRODUCE
OCCASIONALLY MODERATE LAKE EFFECT SNOW SHOWERS THROUGH THIS
AFTERNOON. AS THE WINDS VEER NRLY TONIGHT...THE LES IS EXPECTED TO
DIMINISH.
IWD...AS WINDS VEER TO THE NW AND N TONIGHT...LIGHT TO MODERATE LAKE
EFFECT SNOW SHOWERS WILL MOVE IN...BRINGING MAINLY IFR VSBY AND MVFR
CIGS.
KSAW...EXPECT VFR CONDITIONS THROUGH TODAY BEFORE A TROUGH PASSAGE
FROM THE NORTH BRINGS SOME LIGHT LAKE EFFECT SNOW ACROSS THE
TERMINAL. THE BEST CHANCE FOR OCCASIONAL SNOW SHOWERS WITH
MVFR CONDITIONS WILL BE LATE TONIGHT AND FRIDAY MORNING AFTER WINDS
BECOME MORE NORTHWESTERLY.
&&
.MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 419 PM EST THU DEC 12 2013
A PERIOD OF WNW TO NW GALES IS EXPECTED LATE THIS AFTERNOON THROUGH
THIS EVENING BEFORE DIMINISHING OVERNIGHT WITH HIGH PRES BUILDING
TOWARD THE REGION. HEAVY FREEZING SPRAY WILL ALSO CONTINUE FOR MUCH
OF THE LAKE INTO THIS EVENING. WINDS WILL FINALLY DIMINISH TO
NORTHERLY AT 15 TO 25 KNOTS OVERNIGHT INTO FRIDAY MORNING AS A WEAK
RIDGE PASSES ACROSS THE LAKE. EXPECT 10 TO 20 KT WINDS TO GRADUALLY
BACK TO THE SE BY SATURDAY AHEAD OF DEVELOPING LOW PRESSURE OVER THE
UPPER MS VALLEY. DEPENDING ON THE STRENGTH OF THE LOW AS IT MOVES
ACROSS LAKE SUPERIOR ON SATURDAY NIGHT AND SUNDAY AND THE STRENGTH OF
ANOTHER LOW MOVING UP THE EAST COAST...COULD SEE AN INCREASE IN
NORTHWESTERLY WINDS ON SUNDAY TO 25 TO 30 KTS. THIS WILL BE SHORT-
LIVED AS ANOTHER HIGH SLIDES INTO THE AREA FOR THE BEGINNING OF THE
UPCOMING WORK WEEK.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
LAKE EFFECT SNOW ADVISORY UNTIL 6 AM EST FRIDAY FOR MIZ006-007-
085.
LAKE SUPERIOR...
GALE WARNING UNTIL MIDNIGHT EST TONIGHT FOR LSZ266-267.
HEAVY FREEZING SPRAY WARNING UNTIL 7 AM EST FRIDAY FOR
LSZ263>266.
GALE WARNING UNTIL 11 PM EST THIS EVENING FOR LSZ264-265.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...JLB
LONG TERM...ROLFSON
AVIATION...JLB
MARINE...JLB
AREA FORECAST DISCUSSION...UPDATED
NWS ALBUQUERQUE NM
1141 AM MST THU DEC 12 2013
.UPDATE...
QUICK UPDATE TO LOWER MAX TEMPS IN A FEW MAINLY SOUTH OF I-40
PLACES GIVEN ABUNDANT LOW/MID CLOUD COVER AND SOME LIGHT PRECIP.
DIFFICULT TO KNOW HOW LOW TO GO WITH WAA OCCURRING. LATEST
THOUGHTS WILL BE OUT SHORTLY.
34
&&
.PREV DISCUSSION...1055 AM MST THU DEC 12 2013...
.AVIATION...
18Z TAF CYCLE
COMPLICATED WEATHER SCENARIO FOR AREA TERMINAL SITES TODAY AND
TONIGHT. INITIAL STREAM OF SUBTROPICAL MOISTURE HAS ALLOWED
PRECIPITATION TO BREAK OUT OVER SOUTHERN AND EASTERN AREAS. MAINLY
HIGHER ELEVATION SNOW WITH RAIN ACROSS THE LOW AND MID LEVELS. CANT
RULE OUT MVFR CIGS/VIS RESTRICTIONS IN THE HEART OF THE
SUBTROPICAL FETCH BUT THE MAIN LOWERING OF CIGS AND VIS WILL COME
TONIGHT AS THE UPPER LEVEL LOW TRACKS OVER THE AREA. SNOW LEVELS
WILL BE LOWER TONIGHT AND MOST LIKELY IMPACT GUP/AEG/ABQ. THE
FORECAST TRICKINESS LIES WITH THE MODELLING. MODELS ARE NOT
CONSISTENT AMONGST EACH OTHER. DECIDED TO GO WITH THE MORE BULLISH
NAM APPROACH FOR THE PREVIOUSLY MENTIONED SITES. GFS IS PRIMARILY DRY.
ALSO DECIDED TO KEEP THE POSSIBLE LOW CIG/FOG GENERATION AT ROW
FOLLOWING THE SUBTROPICAL MOISTURE SURGE. COULD GET SOME BRIEF
CLEARING THERE WHICH WOULD ALLOW THE HIGHER LEFTOVER SFC DEWPOINTS
TO FORM VERY LOW CIGS/FG. DIDNT GO HOG WILD AT THIS TIME AND
USING MVFR CIGS/VIS AS A PLACEHOLDER THERE. IF THE NAM MODEL IS
CORRECT THEN AEG/ABQ WOULD SEE IFR AND POSSIBLY LIFR CONDITIONS
DUE TO SNOWFALL. MAIN PERIOD FOR THE PRECIP AT ABQ/AEG RANGES BTWN
8Z TO 15Z. IF THE NAM MODEL IS CORRECT POSSIBLE AWW SNOW AMTS
ALTHOUGH IT MIGHT BE A BIT HARDER TO ACCUM SNOW ON PAVEMENT.
50
.PREV DISCUSSION...303 AM MST THU DEC 12 2013...
WITH THE EXCEPTION OF A BRIEF BOUT OF RAIN/SNOW TODAY/TONIGHT ACROSS
CENTRAL AND WESTERN NM THE OVERALL PATTERN WILL REMAIN RELATIVELY
TRANQUIL THRU THE NEXT 7 DAYS. CURRENTLY A DEEP FETCH OF SUBTROPICAL
MOISTURE SURGING NE OUT OF THE EQUATORIAL PACIFIC WILL SLIDE OVER
SOUTHERN NM AHEAD OF A WEAK UPPER LOW OVER SOCA. THE LATEST HRRR
AND RUC SOLUTIONS SLOW DOWN TIMING OF PRECIP FOR TODAY SO LOWERED
POPS SUBSTANTIALLY THIS MORNING. THE WPC PROBABILISTIC QPF (PQPF)
INDICATES THE BEST SHOT FOR MEASURABLE IN THE SE WILL BE NOON TO
EARLY EVENING. 700MB WARM ADVECTION WITH THIS FETCH WILL RAISE
SNOW LEVELS TO ABOVE 9000 FT. TEMPS EXPECTED TO WARM ABOVE FREEZING
BY THE TIME PRECIP ARRIVES OVER THE AREA THUS SNOW ACCUMS WILL BE
ABOVE RUIDOSO.
MADE SOME NOTABLE CHANGES TO POP DISTRIBUTION FOR CENTRAL/WESTERN
NM LATE TODAY AND TONIGHT. TRENDED TOWARD SREF/GEFS AND WPC PQPF...
WHICH FOCUSES GREATEST CHANCES ALONG THE CONT DVD TONIGHT THEN THE
CENTRAL MT CHAIN/ABQ METRO AREA EARLY FRIDAY. COLD ADVECTION WITH
THE UPPER COLD CORE WILL ALLOW FOR RAIN TO SNOW...HOWEVER QPF IS
LIGHT...SO EXPECT HIGHEST SNOW AMOUNTS OVER HIGHEST TERRAIN. WILL
ISSUE SPS AGAIN SINCE CONFIDENCE ON TIMING/LOCATION OF COLD AIR
AND PRECIP IS TOO LOW FOR ANY ADVISORIES. ACCUMS LOOK MARGINAL TOO
EVEN IF BEST PRECIP COINCIDES WITH COLD AIR AND INSTABILITY.
AFTER THIS QUICK HIT OF RAIN/SNOW COLDER TEMPS WILL AGAIN SLIDE OVER
THE STATE THIS WEEKEND WITH A SERIES OF WEAK WAVES IN NW FLOW.
OTHERWISE IT WILL REMAIN QUIET THRU NEXT WEEK AS TEMPS MODERATE BACK
NEAR TO SLIGHTLY ABV NORMAL. PERIODIC GUSTY BREEZES IN NW FLOW ARE
LIKELY ALONG WIND PRONE AREAS EAST OF THE CENTRAL MT CHAIN.
GUYER
.FIRE WEATHER...
POOR VENTILATION IS EXPECTED AREAWIDE TODAY AS A LOW PRESSURE SYSTEM
THAT HAS BEEN STALLED OFF THE UPPER BAJA COAST BEGINS TO SHIFT
NORTHEASTWARD TOWARD NM. THE BULK OF THE MOISTURE WITH THE SYSTEM
WILL BE ASSOCIATED WITH THE SUBTROPICAL JET...WHICH WILL SHIFT
EASTWARD ACROSS SOUTHERN NM TODAY. MODELS AND OUR FORECAST GRIDS
HAVE SLOWED THE ARRIVAL OF THIS MOISTURE...WITH RAIN AND VERY HIGH
MOUNTAIN SNOWS FAVORING LOCATIONS ALONG AND SOUTH OF HIGHWAY 60 THIS
AFTERNOON. INSTABILITY LOOKS SUFFICIENT FOR A FEW THUNDERSTORMS TO
DEVELOP OVER THE SW MOUNTAINS THIS AFTERNOON...TOO. THE UPPER LEVEL
LOW AND A PACIFIC COLD FRONT ARE THEN PROGGED TO BRING MODEST
MOISTURE AND COLDER TEMPERATURES TO WESTERN AREAS...AND TO A LESSER
EXTENT CENTRAL AND SOUTHERN AREAS...TONIGHT. THE BAJA SYSTEM WILL
EXIT EASTWARD DURING THE AFTERNOON FRIDAY...BUT A SECONDARY UPPER
LOW RIGHT ON ITS HEELS WILL CROSS THE AREA FROM THE NORTHWEST...
KEEPING SHOWERS IN THE FORECAST FOR CENTRAL AND WESTERN AREAS FRIDAY
AND FRIDAY NIGHT. BY LATE FRIDAY...A FEW INCHES OF SNOW ACCUMULATION
WILL BE POSSIBLE IN THE WESTERN MOUNTAINS...WITH LIGHTER AMOUNTS
ACROSS THE REMAINDER OF THE HIGH TERRAIN. FROM THURSDAY THROUGH
FRIDAY NIGHT...LIQUID AND LIQUID EQUIVALENT PRECIPITATION SHOULD
TOTAL AROUND A QUARTER INCH ACROSS SOUTHERN PARTS OF THE FIRE
WEATHER FORECAST AREA...WITH A TENTH OF AN INCH POSSIBLE IN
LOCATIONS AS FAR NORTH AS THE CHUSKA MOUNTAINS AND ALBUQUERQUE. A
FEW HUNDREDTHS OF AN INCH WILL BE POSSIBLE FROM FARMINGTON TO SANTA
FE AND PORTALES.
IN THE WAKE OF THE PACIFIC COLD FRONT...W AND NW WINDS WILL PICK UP
FRIDAY AS A SPEED MAXIMUM IN THE POLAR JET ROUNDS THE BASE OF THE
SECONDARY UPPER TROUGH AND CROSSES SOUTHERN NM. MEANWHILE...A
SURFACE LOW WILL SHIFT SOUTHEASTWARD FROM SE CO OVER THE TX
PANHANDLE KEEPING THE SURFACE PRESSURE GRADIENT TIGHT ACROSS THE
PLAINS. THE STRONGEST NW WINDS SHOULD BE FOUND ALONG AND SOUTH OF
I-40...WITH GUSTS FROM 40 TO PERHAPS 50 MPH EAST OF THE
SANDIA/MANZANO AND GALLINAS MOUNTAINS TO THE PECOS RIVER. BREEZY
CONDITIONS WILL EXTEND EAST OF THERE TO THE TX BORDER.
FORTUNATELY...HUMIDITIES WILL REMAIN ABOVE CRITICAL THRESHOLDS.
BECAUSE OF THE STRONGER WINDS...THERE WILL BE SOME VENTILATION
IMPROVEMENT FRIDAY ALONG AND SOUTH OF I-40...WITH POOR VENTILATION
LINGERING ACROSS MUCH OF THE NORTH.
ONE LAST WEAK AND DRY UPPER TROUGH WILL DIVE SOUTHEASTWARD ACROSS
THE FORECAST AREA SATURDAY...PROMPTLY BEHIND FRIDAYS SECONDARY
SYSTEM. THIS THIRD TROUGH WILL KEEP COLD AIR ADVECTION IN PLACE FOR
ONE LAST DAY. HIGH TEMPERATURES ARE EXPECTED TO BOTTOM OUT SATURDAY
AROUND 3 TO 10 DEGREES BELOW NORMAL. VENTILATION WILL BE POOR
AREAWIDE...EXCEPT FOR SOME IMPROVEMENT ACROSS THE FAR EASTERN PLAINS
DUE TO GUSTY NORTH WINDS LINGERING BEHIND A BACK DOOR COLD FRONT
THAT WILL SINK SOUTHWARD THROUGH THE PLAINS FRIDAY NIGHT.
DRY NW FLOW ALOFT WILL PERSIST THROUGH THE MIDDLE OF THE COMING
WEEK. WEATHER SYSTEMS WILL PASS FAR ENOUGH NORTH TO KEEP
PRECIPITATION OUT OF THE FORECAST FOR NORTHERN AND CENTRAL NM. A
WARMING TREND WILL DEVELOP SUNDAY THROUGH TUESDAY WITH HIGH
TEMPERATURES REACHING ABOVE NORMAL IN MOST LOCATIONS AS EARLY AS
MONDAY. A BACK DOOR COLD FRONT SHOULD THEN DROP SOUTHWARD THROUGH
THE PLAINS TUESDAY NIGHT COOLING TEMPERATURES ACROSS THE EAST FOR
WEDNESDAY. OTHERWISE...VENTILATION WILL GENERALLY BE POOR...EXCEPT
FOR PERIODS OF IMPROVEMENT ACROSS THE EAST CENTRAL PLAINS.
44
&&
.ABQ WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
34
AREA FORECAST DISCUSSION...UPDATED
NWS ALBUQUERQUE NM
1055 AM MST THU DEC 12 2013
.AVIATION...
18Z TAF CYCLE
COMPLICATED WEATHER SCENARIO FOR AREA TERMINAL SITES TODAY AND
TONIGHT. INITIAL STREAM OF SUBTROPICAL MOISTURE HAS ALLOWED
PRECIPITATION TO BREAK OUT OVER SOUTHERN AND EASTERN AREAS. MAINLY
HIGHER ELEVATION SNOW WITH RAIN ACROSS THE LOW AND MID LEVELS. CANT
RULE OUT MVFR CIGS/VIS RESTRICTIONS IN THE HEART OF THE
SUBTROPICAL FETCH BUT THE MAIN LOWERING OF CIGS AND VIS WILL COME
TONIGHT AS THE UPPER LEVEL LOW TRACKS OVER THE AREA. SNOW LEVELS
WILL BE LOWER TONIGHT AND MOST LIKELY IMPACT GUP/AEG/ABQ. THE
FORECAST TRICKINESS LIES WITH THE MODELLING. MODELS ARE NOT
CONSISTENT AMONGST EACH OTHER. DECIDED TO GO WITH THE MORE BULLISH
NAM APPROACH FOR THE PREVIOUSLY MENTIONED SITES. GFS IS PRIMARILY DRY.
ALSO DECIDED TO KEEP THE POSSIBLE LOW CIG/FOG GENERATION AT ROW
FOLLOWING THE SUBTROPICAL MOISTURE SURGE. COULD GET SOME BRIEF
CLEARING THERE WHICH WOULD ALLOW THE HIGHER LEFTOVER SFC DEWPOINTS
TO FORM VERY LOW CIGS/FG. DIDNT GO HOG WILD AT THIS TIME AND
USING MVFR CIGS/VIS AS A PLACEHOLDER THERE. IF THE NAM MODEL IS
CORRECT THEN AEG/ABQ WOULD SEE IFR AND POSSIBLY LIFR CONDITIONS
DUE TO SNOWFALL. MAIN PERIOD FOR THE PRECIP AT ABQ/AEG RANGES BTWN
8Z TO 15Z. IF THE NAM MODEL IS CORRECT POSSIBLE AWW SNOW AMTS
ALTHOUGH IT MIGHT BE A BIT HARDER TO ACCUM SNOW ON PAVEMENT.
50
&&
.PREV DISCUSSION...303 AM MST THU DEC 12 2013...
WITH THE EXCEPTION OF A BRIEF BOUT OF RAIN/SNOW TODAY/TONIGHT ACROSS
CENTRAL AND WESTERN NM THE OVERALL PATTERN WILL REMAIN RELATIVELY
TRANQUIL THRU THE NEXT 7 DAYS. CURRENTLY A DEEP FETCH OF SUBTROPICAL
MOISTURE SURGING NE OUT OF THE EQUATORIAL PACIFIC WILL SLIDE OVER
SOUTHERN NM AHEAD OF A WEAK UPPER LOW OVER SOCA. THE LATEST HRRR
AND RUC SOLUTIONS SLOW DOWN TIMING OF PRECIP FOR TODAY SO LOWERED
POPS SUBSTANTIALLY THIS MORNING. THE WPC PROBABILISTIC QPF (PQPF)
INDICATES THE BEST SHOT FOR MEASURABLE IN THE SE WILL BE NOON TO
EARLY EVENING. 700MB WARM ADVECTION WITH THIS FETCH WILL RAISE
SNOW LEVELS TO ABOVE 9000 FT. TEMPS EXPECTED TO WARM ABOVE FREEZING
BY THE TIME PRECIP ARRIVES OVER THE AREA THUS SNOW ACCUMS WILL BE
ABOVE RUIDOSO.
MADE SOME NOTABLE CHANGES TO POP DISTRIBUTION FOR CENTRAL/WESTERN
NM LATE TODAY AND TONIGHT. TRENDED TOWARD SREF/GEFS AND WPC PQPF...
WHICH FOCUSES GREATEST CHANCES ALONG THE CONT DVD TONIGHT THEN THE
CENTRAL MT CHAIN/ABQ METRO AREA EARLY FRIDAY. COLD ADVECTION WITH
THE UPPER COLD CORE WILL ALLOW FOR RAIN TO SNOW...HOWEVER QPF IS
LIGHT...SO EXPECT HIGHEST SNOW AMOUNTS OVER HIGHEST TERRAIN. WILL
ISSUE SPS AGAIN SINCE CONFIDENCE ON TIMING/LOCATION OF COLD AIR
AND PRECIP IS TOO LOW FOR ANY ADVISORIES. ACCUMS LOOK MARGINAL TOO
EVEN IF BEST PRECIP COINCIDES WITH COLD AIR AND INSTABILITY.
AFTER THIS QUICK HIT OF RAIN/SNOW COLDER TEMPS WILL AGAIN SLIDE OVER
THE STATE THIS WEEKEND WITH A SERIES OF WEAK WAVES IN NW FLOW.
OTHERWISE IT WILL REMAIN QUIET THRU NEXT WEEK AS TEMPS MODERATE BACK
NEAR TO SLIGHTLY ABV NORMAL. PERIODIC GUSTY BREEZES IN NW FLOW ARE
LIKELY ALONG WIND PRONE AREAS EAST OF THE CENTRAL MT CHAIN.
GUYER
.FIRE WEATHER...
POOR VENTILATION IS EXPECTED AREAWIDE TODAY AS A LOW PRESSURE SYSTEM
THAT HAS BEEN STALLED OFF THE UPPER BAJA COAST BEGINS TO SHIFT
NORTHEASTWARD TOWARD NM. THE BULK OF THE MOISTURE WITH THE SYSTEM
WILL BE ASSOCIATED WITH THE SUBTROPICAL JET...WHICH WILL SHIFT
EASTWARD ACROSS SOUTHERN NM TODAY. MODELS AND OUR FORECAST GRIDS
HAVE SLOWED THE ARRIVAL OF THIS MOISTURE...WITH RAIN AND VERY HIGH
MOUNTAIN SNOWS FAVORING LOCATIONS ALONG AND SOUTH OF HIGHWAY 60 THIS
AFTERNOON. INSTABILITY LOOKS SUFFICIENT FOR A FEW THUNDERSTORMS TO
DEVELOP OVER THE SW MOUNTAINS THIS AFTERNOON...TOO. THE UPPER LEVEL
LOW AND A PACIFIC COLD FRONT ARE THEN PROGGED TO BRING MODEST
MOISTURE AND COLDER TEMPERATURES TO WESTERN AREAS...AND TO A LESSER
EXTENT CENTRAL AND SOUTHERN AREAS...TONIGHT. THE BAJA SYSTEM WILL
EXIT EASTWARD DURING THE AFTERNOON FRIDAY...BUT A SECONDARY UPPER
LOW RIGHT ON ITS HEELS WILL CROSS THE AREA FROM THE NORTHWEST...
KEEPING SHOWERS IN THE FORECAST FOR CENTRAL AND WESTERN AREAS FRIDAY
AND FRIDAY NIGHT. BY LATE FRIDAY...A FEW INCHES OF SNOW ACCUMULATION
WILL BE POSSIBLE IN THE WESTERN MOUNTAINS...WITH LIGHTER AMOUNTS
ACROSS THE REMAINDER OF THE HIGH TERRAIN. FROM THURSDAY THROUGH
FRIDAY NIGHT...LIQUID AND LIQUID EQUIVALENT PRECIPITATION SHOULD
TOTAL AROUND A QUARTER INCH ACROSS SOUTHERN PARTS OF THE FIRE
WEATHER FORECAST AREA...WITH A TENTH OF AN INCH POSSIBLE IN
LOCATIONS AS FAR NORTH AS THE CHUSKA MOUNTAINS AND ALBUQUERQUE. A
FEW HUNDREDTHS OF AN INCH WILL BE POSSIBLE FROM FARMINGTON TO SANTA
FE AND PORTALES.
IN THE WAKE OF THE PACIFIC COLD FRONT...W AND NW WINDS WILL PICK UP
FRIDAY AS A SPEED MAXIMUM IN THE POLAR JET ROUNDS THE BASE OF THE
SECONDARY UPPER TROUGH AND CROSSES SOUTHERN NM. MEANWHILE...A
SURFACE LOW WILL SHIFT SOUTHEASTWARD FROM SE CO OVER THE TX
PANHANDLE KEEPING THE SURFACE PRESSURE GRADIENT TIGHT ACROSS THE
PLAINS. THE STRONGEST NW WINDS SHOULD BE FOUND ALONG AND SOUTH OF
I-40...WITH GUSTS FROM 40 TO PERHAPS 50 MPH EAST OF THE
SANDIA/MANZANO AND GALLINAS MOUNTAINS TO THE PECOS RIVER. BREEZY
CONDITIONS WILL EXTEND EAST OF THERE TO THE TX BORDER.
FORTUNATELY...HUMIDITIES WILL REMAIN ABOVE CRITICAL THRESHOLDS.
BECAUSE OF THE STRONGER WINDS...THERE WILL BE SOME VENTILATION
IMPROVEMENT FRIDAY ALONG AND SOUTH OF I-40...WITH POOR VENTILATION
LINGERING ACROSS MUCH OF THE NORTH.
ONE LAST WEAK AND DRY UPPER TROUGH WILL DIVE SOUTHEASTWARD ACROSS
THE FORECAST AREA SATURDAY...PROMPTLY BEHIND FRIDAYS SECONDARY
SYSTEM. THIS THIRD TROUGH WILL KEEP COLD AIR ADVECTION IN PLACE FOR
ONE LAST DAY. HIGH TEMPERATURES ARE EXPECTED TO BOTTOM OUT SATURDAY
AROUND 3 TO 10 DEGREES BELOW NORMAL. VENTILATION WILL BE POOR
AREAWIDE...EXCEPT FOR SOME IMPROVEMENT ACROSS THE FAR EASTERN PLAINS
DUE TO GUSTY NORTH WINDS LINGERING BEHIND A BACK DOOR COLD FRONT
THAT WILL SINK SOUTHWARD THROUGH THE PLAINS FRIDAY NIGHT.
DRY NW FLOW ALOFT WILL PERSIST THROUGH THE MIDDLE OF THE COMING
WEEK. WEATHER SYSTEMS WILL PASS FAR ENOUGH NORTH TO KEEP
PRECIPITATION OUT OF THE FORECAST FOR NORTHERN AND CENTRAL NM. A
WARMING TREND WILL DEVELOP SUNDAY THROUGH TUESDAY WITH HIGH
TEMPERATURES REACHING ABOVE NORMAL IN MOST LOCATIONS AS EARLY AS
MONDAY. A BACK DOOR COLD FRONT SHOULD THEN DROP SOUTHWARD THROUGH
THE PLAINS TUESDAY NIGHT COOLING TEMPERATURES ACROSS THE EAST FOR
WEDNESDAY. OTHERWISE...VENTILATION WILL GENERALLY BE POOR...EXCEPT
FOR PERIODS OF IMPROVEMENT ACROSS THE EAST CENTRAL PLAINS.
44
&&
.ABQ WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS GRAND FORKS ND
330 PM CST THU DEC 12 2013
.SHORT TERM...(THIS EVENING THROUGH FRIDAY NIGHT)
ISSUED AT 330 PM CST THU DEC 12 2013
MAIN FORECAST CONCERNS IN THE SHORT TERM WILL BE EXTENT OF LIGHT
SNOW WITH PASSING UPPER WAVES AND TEMP TRENDS...WITH COLD AIR
REMAINING FIRMLY ENTRENCHED.
A NARROW BAND OF LIGHT SNOW HAS PROGRESSED FROM THE NORTHERN
VALLEY SOUTHEASTWARD INTO NW MINNESOTA THIS AFTERNOON. THIS WILL
CONTINUE TO SHIFT SOUTHEASTWARD THROUGH THE REST OF THE AFTERNOON.
ANOTHER AREA OF LIGHT SNOW WILL SHIFT INTO THE DEVILS LAKE BASIN
THIS EVENING AND SOUTHEASTWARD OVERNIGHT...IN ASSOCIATION WITH AN
AREA OF MID-LEVEL FRONTOGENESIS AND SYNOPTIC FORCING IN THE RIGHT
ENTRANCE REGION OF A BROAD UPPER JET. AS THE FORCING GRADUALLY
WEAKENS...A DECREASING TREND IN THE SNOWFALL IS EXPECTED WITH TIME
AS THE SNOW SHIFTS SOUTHWARD. RIGHT NOW THE BEST CHANCE FOR 1 TO 3
INCHES OF ACCUMULATION LOOKS TO BE FROM THE DEVILS LAKE AREA INTO
PARTS OF THE NORTHERN AND CENTRAL VALLEY TONIGHT INTO FRIDAY.
TEMPS TONIGHT MAY BE TRICKY. ALTHOUGH LOW-LEVEL COLD ADVECTION
WILL CONTINUE THROUGH THE NIGHT...HOW MUCH TEMPS FALL WILL DEPEND
ON CLOUD COVERAGE. THE RAP BRINGS SOME LOW-LEVEL DRYING INTO PARTS
OF NORTHWEST MINNESOTA OVERNIGHT. TEMPS COULD DROP PRETTY QUICKLY
IF ANY CLEARING DOES OCCUR...AND THUS HAVE THE LOWEST TEMPS IN
THIS AREA OF NW MINNESOTA. HIGHS ON FRIDAY LIKELY WILL BE COLDEST
NORTH...WITH TEMPS REMAINING BELOW ZERO...AND SINGLE DIGITS ABOVE
ZERO FARTHER SOUTH.
AS WINDS ARE EXPECTED TO STAY UP AROUND 10 KTS OVERNIGHT...WILL
ALSO ISSUE A WIND CHILL ADVISORY FOR MUCH OF NE ND EASTWARD INTO
NW MN FROM 06Z TONIGHT THROUGH 03Z SATURDAY. WITH WINDS BRISK FROM
THE NORTHEAST ON FRIDAY AHEAD OF THE SFC HIGH...HELD ONTO THE
ADVISORY UNTIL FRIDAY EVENING...ALTHOUGH WIND CHILLS MAY RISE ABOVE
CRITERIA FOR A BIT DURING THE DAY. AS THE SFC RIDGE AXIS
APPROACHES FRIDAY NIGHT...WINDS MAY GO LIGHT...ALLOWING FOR WIND
CHILLS TO RISE ABOVE ADVISORY THRESHOLD. THIS WILL BE MONITORED
DURING FUTURE SHIFTS THOUGH.
A SERIES OF UPPER IMPULSES EMBEDDED IN NORTHWEST FLOW ALOFT WILL
CONTINUE TO AFFECT THE AREA FRIDAY NIGHT INTO SATURDAY...BRINGING
CONTINUED CHANCES FOR LIGHT SNOW. ALTHOUGH MODEL QPF IS LOW...WITH
HIGH SNOW RATIOS AND MODEL SOUNDINGS INDICATING A FAIRLY DEEP
SATURATED LAYER...A FLUFFY INCH OR TWO OF SNOW IS
POSSIBLE...DEPENDING ON THE EXACT TRACK OF THE IMPULSES.
.LONG TERM...(SATURDAY THROUGH THURSDAY)
ISSUED AT 330 PM CST THU DEC 12 2013
TEMPS ON SATURDAY WILL RISE INTO THE SINGLE DIGITS EITHER SIDE OF
ZERO WITH LIGHT SNOW REMAINING POSSIBLE AS UPPER LEVEL ENERGY
CASCADES THROUGH THE FLOW. A SFC RIDGE WILL SPREAD OVER THE AREA
ON SATURDAY NIGHT. THE MAIN QUESTION WILL BE TEMPS...WHICH WILL BE
DEPENDENT ON CLOUD COVER. THUS...TEMPS COULD BE A BIT COLDER IF
SKIES DO CLEAR.
ANOTHER ROUND OF LIGHT SNOW IS POSSIBLE SUNDAY AS WARM AIR ADVECTION
DEVELOPS AND THE LOW-LEVEL BAROCLINIC ZONE APPROACHES FROM THE WEST
AHEAD OF THE NEXT UPPER WAVE. HOWEVER...TEMPS WILL REMAIN WELL
BELOW NORMAL.
FOR THE SUNDAY NIGHT THROUGH THURSDAY PERIOD...12Z ECMWF/GFS/GEM SO
ENOUGH DISAGREEMENT IN TIMING AND LOCATION OF SEVERAL 500 MB SHORT
WAVES/SURFACE LOW PRESSURE SYSTEMS TO KEEP CONFIDENCE IN FCST A BIT
LOWER THAN NORMAL. IDEA IS FOR ONE SHORT WAVE MONDAY TO EXIT
FOLLOWED BY SOME COLDER AIR MON NIGHT-TUE THEN THE NEXT ONE DUE WED
NIGHT-THU TIME FRAME. EXACT PLACEMENT OF LOWS WILL MEAN POTENTIAL
TEMP DIFFERENCES WITH OVERALL 12Z EURO AND GEM A BIT WARMER THAN 12Z
GFS ESP FOR MID WEEK SYSTEM. WITH THE DIFFERENCES STUCK WITH ALL
BLEND GUIDANCE. THERAFTER AND BEYOND THIS PERIOD IS WHEN THE NEXT
ARCTIC OUBREAK WILL OCCUR.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z FRIDAY AFTERNOON)
ISSUED AT 1245 PM CST THU DEC 12 2013
EXPECT MVFR-VFR CONDITIONS THRU THE PERIOD. MVFR CIGS INTO DVL
REGION AND EXPECT THE VFR CIGS ELSEWHERE TO GRADUALLY TURN MORE
MVFR OVERNIGHT INTO FRIDAY AS COLD FRONT SINKS SOUTH. SOME VERY
LIGHT SNOW WITH THIS FEATURE NRN VALLEY INTO FAR NW MN BUT VSBY
P6SM. A BIT BETTER CHANCE FOR SOME 3-5SM VSBYS IN -SN LATE TONIGHT
INTO FRIDAY WITH NEXT WAVE. WINDS WILL TURN TO A MORE NORTH-
NORTHEAST DIRECTION AT 10 TO 18 KTS TONIGHT AND FRIDAY.
&&
.FGF WATCHES/WARNINGS/ADVISORIES...
ND...WIND CHILL ADVISORY FROM MIDNIGHT TONIGHT TO 9 PM CST FRIDAY FOR
NDZ006>008-014>016-024-026>030-054.
MN...WIND CHILL ADVISORY FROM MIDNIGHT TONIGHT TO 9 PM CST FRIDAY FOR
MNZ001-002-004>009-013>017-022-023.
&&
$$
SHORT TERM...MAKOWSKI
LONG TERM...RIDDLE
AVIATION...RIDDLE
AREA FORECAST DISCUSSION
NWS BISMARCK ND
112 PM CST THU DEC 12 2013
.UPDATE...
ISSUED AT 102 PM CST THU DEC 12 2013
QUIET WEATHER ACROSS THE NORTHERN PLAINS TODAY. DIM SUNSHINE
PEEKING THROUGH THE SOUTH. CLOUDY NORTH. VERY LITTLE SNOW FALLING
NORTH SO WILL JUST GO FLURRIES FOR THE AFTERNOON. TEMP SENSOR AT
BAKER MONTANA MALFUNCTIONING SO REMOVED FROM THE GRIDDED DATABASE
AS THIS WAS INFLATING THE CURRENT TEMPERATURES ACROSS THE FAR
SOUTHWEST.
UPDATE ISSUED AT 934 AM CST THU DEC 12 2013
AT 9 AM CST...A WARM FRONTAL BOUNDARY ACROSS NORTHEAST MONTANA
AND SOUTHWEST NORTH DAKOTA WILL BE THE FOCUS FOR LIGHT SNOW ACROSS
NORTH CENTRAL NORTH DAKOTA. THE CHANCE OF SNOW WILL INCREASE
ACROSS THE NORTH CENTRAL TONIGHT AND FRIDAY. FOR TODAY...EXPECT
LITTLE SNOW ACROSS THE SOUTH. KEPT 20-30 POPS ACROSS THE NORTH.
TEMPERATURES ACROSS THE REGION WILL REMAIN COOL NORTHEAST. SHOULD
GET CLOSE TO THE FREEZING MARK SOUTHWEST.
UPDATE ISSUED AT 643 AM CST THU DEC 12 2013
UPDATE FOR POPS AND TEMPERATURE TRENDS. BASED ON 11Z RAP GUIDANCE
AND RADAR/OBS TRENDS...HAVE EXPANDED AREA OF LIGHT SNOW SHOWERS TO
INCLUDE MOST OF THE FORECAST AREA THIS MORNING. THE FOCUS OF THE
SNOW LATER THIS AFTERNOON WILL BE THE FAR NORTH. HOWEVER...MOST
ACCUMULATING SNOW WILL OCCUR AFTER 00Z THIS EVENING.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 327 AM CST THU DEC 12 2013
THE HIGHLIGHT OF THE SHORT TERM IS A BREAK FROM THE ARCTIC
AIR...ESPECIALLY SOUTHWEST AND SOUTH CENTRAL TODAY...FOLLOWED BY
ACCUMULATING SNOW TONIGHT NORTH CENTRAL.
CONTINUED POPS THROUGH 15 UTC ACROSS THE NORTHWEST BASED UPON
LATEST RADAR TRENDS THROUGH 0945 UTC AND THE 08 UTC RAP WHICH IS THE
JUST ABOUT THE ONLY DETERMINISTIC MODEL CAPTURING THE LIGHT SNOW
PROPAGATING IN FROM NORTHEAST MONTANA AND SOUTHEAST SASKATCHEWAN
THIS MORNING.
A QUASI-STATIONARY FRONT ACROSS NORTHWEST THROUGH SOUTHEAST NORTH
DAKOTA THIS MORNING WILL SLOWLY PROPAGATE SOUTHWEST THROUGH THE
DAY AS A COLD FRONT. ON THE WARM SIDE OF THIS BOUNDARY WIDESPREAD
HIGHS IN THE 20S...AND PERHAPS A FEW LOWER 30S ACROSS THE FAR
SOUTHWEST ARE EXPECTED. IN CONTRAST...HIGHS IN THE SINGLE DIGITS
ARE FORECAST ACROSS THE TURTLE MOUNTAINS...WHICH IS IN LINE WITH
THE 00 UTC GUIDANCE CONSENSUS. AS THE LOW LEVEL BAROCLINIC ZONE
STRENGTHENS LATE THIS AFTERNOON AND INTO THE EVENING AS THE
SOUTHERN PERIPHERY OF ARCTIC HIGH PRESSURE BUILDS INTO NORTHERN
NORTH DAKOTA...A BAND OF LIGHT TO MODERATE SNOW IS EXPECTED TO
DEVELOP ACROSS NORTH CENTRAL AND NORTHEAST NORTH DAKOTA AS
FRONTOGENETICAL FORCING INCREASES. ONE TO THREE INCHES OF SNOW IS
EXPECTED FOR THE US HIGHWAY 2 CORRIDOR ACROSS THE NORTH CENTRAL.
AT THIS TIME...WILL HIGHLIGHT THE EVENT WITH AN SPS...ALSO
MENTIONING WIND CHILLS TO 25 BELOW AS ARCTIC AIR BUILDS SOUTH
COUPLED WITH EASTERLY WINDS OF 10-15 KTS WITH THE TIGHT PRESSURE
GRADIENT ON THE SOUTHERN PERIPHERY OF THE SURFACE HIGH.
.LONG TERM...(FRIDAY THROUGH WEDNESDAY)
ISSUED AT 327 AM CST THU DEC 12 2013
THE MAIN FORECAST ISSUE IS TIMING AND COVERAGE OF SEVERAL LIGHT
SNOW EVENTS THROUGH THE PERIOD.
ON FRIDAY...ANOTHER SURGE OF ARCTIC AIR WILL SPREAD SOUTH ACROSS
THE STATE. LIGHT SNOW WILL CONTINUE FRIDAY...WITH ADDITIONAL
ACCUMULATION FOCUSED ON THE NORTHERN COUNTIES. 1 TO 2 MORE INCHES
WILL BE POSSIBLE THROUGH FRIDAY NIGHT...WITH GENERALLY A LIGHT
DUSTING POSSIBLE IN CENTRAL AND SOUTHERN NORTH DAKOTA. ANOTHER
WEAK SHORT WAVE MAY SUPPORT LIGHT ACCUMULATIONS AGAIN SATURDAY
NIGHT. WIND CHILLS AROUND 25 BELOW ZERO ARE POSSIBLE FRIDAY NIGHT
AND SATURDAY NIGHT ACROSS THE NORTH. LOOKING AHEAD...THERE IS SOME
UNCERTAINTY AS TO HOW FAR EAST THE UPPER RIDGE AND MILDER AIR WILL
PUSH. THE SOUTHWEST PART OF THE STATE...AT THE LEAST...SHOULD WARM
INTO THE 20S AND EVEN LOWER 30S FROM SUNDAY THROUGH WEDNESDAY.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z FRIDAY AFTERNOON)
ISSUED AT 102 PM CST THU DEC 12 2013
VFR ACROSS THE REGION AS A WEAK WARM FRONT IN EASTERN MONTANA NOT
PRODUCING MUCH WEATHER AT THIS TIME. EXPECT VFR ACROSS THE REGION
INTO THIS EVENING. AT THIS TIME EXPECT KMOT TO BE IMPACTED BY MVFR
CONDITIONS THIS EVENING AFTER 00Z. MAY PUSH THIS BACK TO ALMOST
06Z TONIGHT AS AM WAITING FOR UPPER LEVEL DISTURBANCE TO MOVE
ACROSS THE AREA. CONDITIONS DETERIORATING TO IFR KMOT AFTER 12Z.
&&
.BIS WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...WAA
AVIATION...WAA
AREA FORECAST DISCUSSION
NWS AUSTIN/SAN ANTONIO TX
300 PM CST THU DEC 12 2013
.SHORT TERM (TONIGHT THROUGH FRIDAY NIGHT)...
MID TO UPPER LEVEL CLOUDS ARE COVERING ALL OF SOUTH CENTRAL TEXAS
THIS AFTERNOON AS SOUTHWEST FLOW ALOFT PUSHES MOISTURE ACROSS THE
AREA. THESE CLOUDS WILL LINGER AROUND THROUGH FRIDAY AS AN UPPER
LEVEL TROUGH TRAVELS FROM THE DESERT SOUTHWEST INTO THE SOUTHERN
PLAINS. AT LOWER LEVELS...VISIBLE SATELLITE IMAGES ARE DEPICTING
BROKEN TO OVERCAST SKIES PUSHING TO THE NORTH-NORTHEAST ACROSS THE RIO
GRANDE VALLEY WHILE SPREADING NORTHEASTWARD TOWARD THE SAN ANTONIO
AREA. LATEST RUC SOLUTION HAS THIS LOW LEVEL CLOUD DECK SPREADING
ACROSS MOST AREAS OF SOUTH CENTRAL TEXAS BY MIDNIGHT. OVERNIGHT
LOWS WILL RANGE FROM THE MID TO UPPER 30S HILL COUNTRY TO LOWER
40S REST OF THE AREA. LATE TONIGHT INTO FRIDAY...CHANCES OF RAIN
WILL BE INCREASING AS THE UPPER LEVEL TROUGH ABOVE MENTIONED NEARS
THE SOUTHERN PLAINS. EXPECT SHOWERS TO AFFECT THE NORTHWEST AND
NORTHERN SECTIONS OF SOUTH CENTRAL TEXAS OVERNIGHT WITH SHOWERS
SPREADING EASTWARD ON FRIDAY. RAIN CHANCES WILL COME TO AN END
LATE FRIDAY AS THE UPPER TROUGH PUSHES TO THE EAST. RAINFALL
AMOUNTS WILL GENERALLY BE FROM A FEW HUNDREDTHS TO ONE QUARTER
INCH...ESPECIALLY ACROSS THE NORTHEAST PART OF THE HILL COUNTRY.
&&
.LONG TERM (SATURDAY THROUGH THURSDAY)...
A DRY COLD FRONT IS EXPECTED TO PUSH ACROSS SOUTH CENTRAL TEXAS
ON SATURDAY WITH SKIES CLEARING FROM WEST TO EAST BY THE AFTERNOON.
MODERATE NORTHWESTERLY WINDS ARE EXPECTED IN THE WAKE OF THE FRONT
WITH WIND SPEEDS DECREASING LATE SATURDAY INTO SUNDAY. SEVERAL
COOL NIGHTS ARE EXPECTED IN THE WAKE OF THE FRONTAL PASSAGE WITH
OVERNIGHT LOWS IN THE LOWER 30S OVER THE HILL COUNTRY AND MID 30S
REST OF THE AREA ON SUNDAY WITH SIMILAR LOWS MONDAY MORNING.
A NORTHWEST TO ZONAL FLOW ALOFT IS ANTICIPATED FOR MUCH OF NEXT
WEEK WITH DRY AND WARMING WEATHER CONDITIONS IN STORE THROUGH
THURSDAY OF NEXT WEEK. LATEST GFS AND ECMWF SOLUTIONS CONTINUE TO
SHOW ANOTHER ARCTIC AIRMASS ARRIVING TO THE LOCAL AREA BETWEEN
SATURDAY AND SUNDAY...DECEMBER 21 AND 22.
&&
.PRELIMINARY POINT TEMPS/POPS...
AUSTIN CAMP MABRY 39 56 44 55 33 / 10 40 20 10 -
AUSTIN BERGSTROM INTL AIRPORT 37 58 42 56 32 / 10 40 20 10 -
NEW BRAUNFELS MUNI AIRPORT 40 58 44 57 33 / 10 30 20 10 -
BURNET MUNI AIRPORT 37 56 40 52 30 / 20 40 10 - -
DEL RIO INTL AIRPORT 40 63 41 60 34 / 10 10 - 0 -
GEORGETOWN MUNI AIRPORT 37 56 42 52 31 / 20 40 20 10 -
HONDO MUNI AIRPORT 40 60 43 61 32 / 10 30 10 - -
SAN MARCOS MUNI AIRPORT 39 59 44 57 33 / 10 40 20 10 -
LA GRANGE - FAYETTE REGIONAL 41 60 47 57 33 / 10 40 30 10 -
SAN ANTONIO INTL AIRPORT 41 58 45 59 34 / 10 30 20 - -
STINSON MUNI AIRPORT 43 60 46 61 35 / 10 30 20 10 -
&&
.EWX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
MESOSCALE/AVIATION...13
SYNOPTIC/GRIDS...17
PUBLIC SERVICE/DATA COLLECTION...33
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
1146 AM CST THU DEC 12 2013
.UPDATE...
ISSUED AT 1146 AM CST THU DEC 12 2013
BASED ON GOES IMAGERY...HAVE MADE SOME MINOR ADJUSTMENTS TO SKY
CLOVER TODAY WITH A CLEAR PERIOD GIVING WAY TO MORE CLOUDS IN THE
LATE AFTERNOON. FORECAST HAD TOO MUCH CLOUD.
ALSO..HAVE INCREASED TEMPERATURES 2-3F FOR AREAS OF SOUTHEAST MN
BASED ON CURRENT TEMPERATURE TRENDS.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 329 AM CST THU DEC 12 2013
CURRENTLY AS OF 09Z...WATER VAPOR LOOP AND RAP 500MB HEIGHT ANALYSIS
SHOWED RIDGING OVER THE WESTERN U.S. INTO SOUTHWEST CANADA...AND
TROUGHING OVER EASTERN CANADA INTO THE GREAT LAKES. IN THE NORTHWEST
FLOW BETWEEN THE RIDGE AND TROUGH...A SHORTWAVE WAS NOTED OVER
NORTHWEST WISCONSIN. DPVA FORCING FROM THE SHORTWAVE COMBINED WITH
ISENTROPIC LIFT ON THE 275-280K SURFACES AS SUGGESTED BY THE RAP HAS
SPREAD LIGHT SNOW ACROSS THE NORTHEAST HALF OF THE FORECAST AREA. IN
ADDITION...THE CLOUDS AND A WARM ADVECTION SOUTHWEST WIND IN THE LOW
LEVELS HAS CAUSED TEMPERATURES TO CLIMB OVERNIGHT. THE BREEZE...
HOWEVER...HAS HELD WIND CHILLS DOWN TO 10 TO 20 BELOW ZERO SOUTHWEST
OF I-94 TO 20 TO 25 BELOW ZERO TO THE NORTH. REGARDING THE WARM
ADVECTION HIGHER ABOVE THE SURFACE...FROM 00Z SOUNDINGS...850MB
TEMPS WERE AROUND -20C OVER THE FORECAST AREA COMPARED TO -7C AT
BIS AND AROUND -10C AT ABR AND OAX. FARTHER UPSTREAM...PLENTY OF
HIGH CLOUDS REFLECTING PACIFIC MOISTURE WERE STREAMING INTO NORTH
DAKOTA IN THE WAKE OF THE SHORTWAVE.
FIRST...WITH RESPECT TO THE WIND CHILL HAZARDS...WILL LET THEM
EXPIRE AT 12Z. ALTHOUGH WIND CHILLS ARE IMPROVING...THERE IS ONLY A
FEW HOURS LEFT TO THE ADVISORY...AND THEY ARE STILL CHILL AS
MENTIONED ABOVE.
ONGOING SNOW EARLY THIS MORNING REMAINS ON TRACK TO QUICKLY EXIT THE
FORECAST AREA...LIKELY BY 7 AM...AS THE SHORTWAVE HEADS OFF TO LAKE
MICHIGAN BY 12Z. OTHERWISE...THE REST OF THE SHORT TERM GENERALLY
LOOKS QUIET PRECIPITATION-WISE AS THE UPPER LEVEL FLOW BECOMES MORE
ZONAL OVER THE NORTHERN U.S.. THE 12.00Z GFS/CANADIAN AND 12.03Z
SREF ALL SHOW SOME LIGHT SNOW OR FLURRIES FALLING LATE THIS
AFTERNOON INTO EARLY THIS EVENING FROM TAYLOR COUNTY NORTHWARD. THIS
LIGHT PRECIPITATION IS ASSOCIATED WITH WEAK BUT MAINTAINED
ISENTROPIC LIFT AND MID-LEVEL FRONTOGENESIS. DECIDED TO ADD SOME LOW
CHANCES ON THE ORDER OF 20 PERCENT TO TAYLOR COUNTY. DESPITE MAINLY
DRY WEATHER FOR THE NEXT 24 HOURS...WE SHOULD SEE QUITE A BIT OF
CLOUD COVER...ESPECIALLY OVER THE NORTH HALF OF THE FORECAST AREA.
THESE CLOUDS OF THE MID/HIGH LEVEL VARIETY REFLECT BOTH THE PACIFIC
MOISTURE FLOWING IN BEHIND THE CURRENT SHORTWAVE AS WELL AS THE
GENERAL WARM ADVECTION PATTERN. ADDITIONALLY...LATE TONIGHT...THE
FORECAST AREA LIES IN THE RIGHT ENTRANCE REGION OF AN UPPER JET
STREAK OVER THE UPPER GREAT LAKES...FAVORING CLOUDS.
WARMER TEMPERATURES ARE ON TRACK TODAY AS SOUTHWEST WINDS BRING UP
WARMER AIR OUT OF NEBRASKA. THE 24 HOUR CHANGE AT 850MB IS FAIRLY
IMPRESSIVE...FROM THE -20C OBSERVED BACK AT 00Z YESTERDAY EVENING TO
-2C TO -10C FOR THIS EVENING. WE CERTAINLY WILL NOT MIX TO THESE
VALUES GIVEN TIME OF YEAR...CLOUDS AND SNOW COVER...BUT DEFINITELY
WARMER NONETHELESS. COLDEST READINGS WILL REMAIN IN THE CHIMNEY
AREA. AS THE UPPER FLOW TURNS ZONAL TONIGHT...A COLD FRONT CURRENTLY
OVER SOUTHERN SASKATCHEWAN IS PROGGED TO SLIDE SOUTH THROUGH THE
FORECAST AREA. THE COLD AIR IS SHALLOW BEHIND THIS FRONT AS MUCH OF
THE TEMPERATURE FALL TAKES PLACE AT 925MB AND BELOW. 925MB TEMPS
FALL 6C ON A NORTH TO NORTHEAST WIND...SO WE SHOULD SEE A DECENT
TEMPERATURE DROP TONIGHT DESPITE CLOUDS IN PLACE.
.LONG TERM...(FRIDAY THROUGH WEDNESDAY)
ISSUED AT 329 AM CST THU DEC 12 2013
FOR FRIDAY THROUGH SATURDAY...ATTENTION TURNS TO AN UPPER LOW
CURRENTLY SITTING NEAR FAR SOUTHERN CALIFORNIA. 12.00Z MODELS
REMAIN CONSISTENT ON TRACKING THIS FEATURE INTO THE CENTRAL
PLAINS ON FRIDAY...THEN UP THROUGH THE OHIO VALLEY FRIDAY NIGHT
AND SATURDAY. THIS TRACK WOULD KEEP THE BULK OF THE SYSTEMS
PRECIPITATION... INCLUDING THE DEFORMATION SHIELD...SOUTHEAST OF
THE FORECAST AREA. 12.00Z ECMWF SHOWS A COMPLETELY DRY FORECAST
FOR THE AREA. HOWEVER...THE 12.00Z GFS/CANADIAN/NAM SUGGEST
POTENTIAL FOR LIGHT SNOW THROUGH THIS ENTIRE PERIOD. ALL
INDICATIONS FROM THESE MODELS SUGGEST THE OHIO VALLEY SHORTWAVE
TROUGH IS NOT THE CAUSE FOR THE PRECIPITATION...BUT ACTUALLY 2
NORTHERN STREAM SHORTWAVE TROUGHS DIGGING DOWN THROUGH THE AREA
AND LINGERING WEAK MID LEVEL FRONTOGENESIS FROM TONIGHT. HARD TO
SAY REALLY WHAT SOLUTION WILL END UP VERIFYING...THE DRY ECMWF OR
THE WETTER GFS/CANADIAN/NAM... BUT EVEN THE WETTER SOLUTION DOES
NOT LOOK TO AMOUNT TO MUCH ACCUMULATION. CONSENSUS WARRANTS
MAINTAINING AT LEAST A 20 PERCENT CHANCE OVER TAYLOR/CLARK
COUNTIES ON FRIDAY...INCREASING CHANCES TO 30-40 PERCENT FRIDAY
NIGHT...THEN DECREASING TOWARDS 20-30 PERCENT BY SATURDAY
AFTERNOON. ALSO BELIEVE THE CHANCES ARE NEEDED AS EVEN THE ECMWF
SHOWS THE 2 NORTHERN STREAM SHORTWAVE TROUGHS. WHETHER WE GET
PRECIPITATION OR NOT...ALL MODELS AGREE ON PLENTY OF CLOUD COVER.
DESPITE THESE CLOUDS...CONSENSUS OF GUIDANCE SUGGESTS TEMPERATURES
WILL BE WARMER THAN WHAT HAS BEEN SEEN RECENTLY. SOME OF THIS IS
DUE TO SLIGHTLY WARMER AIR GETTING PULLED UP TOWARDS THE AREA
AROUND THE SYSTEM TRACKING INTO THE OHIO VALLEY.
OF THE TWO AFOREMENTIONED SHORTWAVE TROUGHS...THE SECOND ONE IS
MUCH MORE POTENT...DIGGING INTO LAKE SUPERIOR AND UPPER MICHIGAN
SATURDAY NIGHT. SOME LIGHT SNOW COULD OCCUR ACROSS AT LEAST
WISCONSIN PORTIONS OF THE AREA SATURDAY NIGHT AS THIS TROUGH DIGS
SOUTH. MORE IMPORTANTLY IS THE COLD SHOT OF AIR FOLLOWING IN ITS
WAKE...WHICH LIKE THE ONE COMING IN TONIGHT IS SHALLOW AS SEEN IN
925MB VERSUS 850MB PROGS. THE 12.00Z ECMWF IS BY FAR THE COLDEST
BRINGING 925MB TEMPS DOWN TO -13 TO -20C AT 18Z SUNDAY. HIGHS AT A
MINIMUM ARE LIKELY IN THE LOW TO MID TEENS...AND IF THE ECMWF IS
RIGHT TAYLOR COUNTY DOES NOT REACH 10 ABOVE.
LOOKING AHEAD TO NEXT WEEK...12.00Z ECMWF/GFS/CANADIAN/GFS ENSEMBLES
AGREE ON A NORTHWEST FLOW PATTERN FOR EARLY IN THE WEEK WITH
TROUGHING OVER THE GREAT LAKES. DESPITE BEING IN THE TROUGH AND
NORTHWEST FLOW...ITS ACTUALLY A WARM ADVECTION PATTERN IN THE LOW
LEVELS. THUS...LOW PRECIPITATION CHANCES ARE NEEDED...ESPECIALLY
ACROSS WISCONSIN WHERE THE FORCING IS STRONGEST. SOME HINTS THAT THE
FORCING WEAKENS ON TUESDAY...ENOUGH SO THAT CHANCES ARE ONLY INCLUDE
UP AROUND TAYLOR COUNTY. AS WE HEAD TOWARDS WEDNESDAY A POTENT
TROUGH STARTS DIGGING INTO THE PACIFIC NORTHWEST...PRODUCING ZONAL
FLOW DOWNSTREAM. THAT IS IF YOU BELIEVE THE ECMWF...BECAUSE THE GFS
DIGS A SHORTWAVE TROUGH DOWN INTO THE OHIO VALLEY. BOTH MODELS
SUGGEST DRY CONDITIONS...BUT THERE ARE MASSIVE TEMPERATURE
DIFFERENCES. GIVEN A SIMILAR SPLIT IN THE GFS ENSEMBLES...HAVE SPLIT
THE DIFFERENCE FOR NOW ON TEMPS.
FARTHER OUT...IT APPEARS AFTER A BRIEF POSSIBLE WARM UP ON WEDNESDAY
AND THURSDAY...ANOTHER BIG SURGE OF ARCTIC AIR LOOKS POISED TO DROP
DOWN INTO THE NORTH CENTRAL U.S. HEADING INTO THE FIRST OFFICIAL
WEEKEND OF WINTER.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z FRIDAY AFTERNOON)
ISSUED AT 1146 AM CST THU DEC 12 2013
A WEATHER SYSTEM MOVING THROUGH NORTHERN WI AND NORTHERN MN LATER
TONIGHT AND FRIDAY WILL BRING LOWERING CLOUDS DURING THE PERIOD TO
THE TAF SITES. NO WEATHER IS EXPECTED FROUM THIS SYSTEM AT THE TAF
LOCATIONS...HOWEVER...CIGS MAY WORK TOWARD MVFR FRIDAY AFTERNOON.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
UPDATE...BAUMGARDT
SHORT TERM...AJ
LONG TERM...AJ
AVIATION...BAUMGARDT