Forecast Discussions mentioning any of
"HRRR" "RAP" "RR" "RUC13" "RUC" received at GSD on 12/11/13
AREA FORECAST DISCUSSION
NWS DENVER/BOULDER CO
904 PM MST TUE DEC 10 2013
.UPDATE...
&&
.SHORT TERM...THE STRONGER WINDS HAVE DECREASED DURING THE PAST
HOUR EXCEPT FOR SOME LOCALIZED HIGHER GUSTS IN THE 50-60 MPH
RANGE. WILL BE CANCELLING THE HIGH WIND WARNING SHORTLY. REST OF
THE FORECASTS IN GOOD SHAPE BUT DID BEEF UP THE WINDS IN THE
HIGHER FOOTHILLS A BIT FOR LATER TNT.
.AVIATION...SURFACE WINDS HAVE SHIFTED SOUTHEAST AT DEN/APA BUT
STILL SOME GUSTY NW WINDS AT BJC STILL FOR A FEW MORE HOURS. WINDS
WILL RETURN TO DRAINAGE CONDITIONS LATER TONIGHT.
&&
.HYDROLOGY...ISSUED A FLOOD ADVISORY FOR THE ICE JAM BREAK ALONG
CREEK CREEK AROUND GOLDEN. APPEARS MOST OF THE HIGHER WATERS IS
MINOR WITH SOME FLOODING ALONG BIKE TRAILS AND SUCH. WILL CONTINUE
ADVISORY UNTIL 8 AM WEDNESDAY AM.
&&
.PREV DISCUSSION... /ISSUED 528 PM MST TUE DEC 10 2013/
UPDATE...
SHORT TERM...CRAZY WINDS JUST WON`T GO AWAY AS STRONGER WINDS
HAVE AGAIN INCREASED AGAIN ACROSS BOULDER AND NORTHERN JEFFERSON
COUNTIES. STRONG MOUNTAIN TOP STABILITY AND ENHANCED SUBSIDENCE
COMING DOWN FROM WYOMING SEEM TO BE THE CULPRIT FOR THE INCREASED
WINDS. DON`T EXPECT THE HIGH WINDS TO LAST PAST LATER THIS
EVENING DUE TO A FRONT MOVING INTO THE AREA WHICH WILL CONTINUEDDECREASE
THE SURFACE GRADIENT ACROSS THE STATE AND STRONGEST SUBSIDENCE
MOVE SOUTH OF THE WARNING AREA LATER THIS EVENING. HAVE ISSUED A
SHORT FUSED HIGH WIND WARNING FOR FOOTHILLS AND ADJ PLAINS UNTIL
10 PM THIS EVENING.
AVIATION...SURFACE WINDS HAVE SHIFTED NORTHEAST AT DENVER AND NOW
JUST SHIFTING NORTHEAST INTO BJC AS THE FRONT MOVES IN. BOULDER
AIRPORT WILL SEE STRONG WINDS IN EXCESS OF 60 MPH UNTIL 8 PM THEN
DECREASING.
PREV DISCUSSION... /ISSUED 454 PM MST TUE DEC 10 2013/
UPDATE...ONE LAST BIG PUSH OF WIND OCCURRING ALONG THE FOOTHILLS
BEFORE THE WAVE DEPARTS UP TO HIGHER ELEVATIONS AS A COLD FRONTAL
PUSH MOVES IN FROM THE NORTHEAST. THE WINDS SHOULD BE DECREASING
WITHIN THE NEXT COUPLE OF HOURS AS THIS FRONT PUSHES IN. AREAS OF
BLOWING SNOW FROM THE GUSTY WINDS ARE DECREASING VISIBILITIES
ALONG THE FOOTHILLS AND TOWARD THE WYOMING BORDER...CAUSING
HAZARDOUS DRIVING CONDITIONS. THIS WILL BE SUBSIDING DURING THE
EVENING.
AVIATION...THE COLD FRONTAL PUSH OUT ON THE EASTERN PLAINS IS
EXPECTED TO PUSH INTO THE DEN AND APA AIRPORTS TO TURN THE NORTH-
NORTHWESTERLY WINDS AROUND TO THE EAST THEN SOUTH LATER TONIGHT.
BJC WILL CONTINUE BLOWING OUT OF THE WEST WITH GUSTS UP TO 40 MPH
FOR THE NEXT COUPLE HOURS BEFORE DIMINISHING...LIKELY TO LIGHT AND
VARIABLE FOR A SHORT TIME. WINDS STAYING SOUTH-SOUTHWEST THROUGH
18Z WITH LIGHT SPEEDS THEN BECOME SLIGHTLY WESTERLY AGAIN...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.
PREV DISCUSSION... /ISSUED 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...ENTREKIN
LONG TERM....COOPER
AVIATION...ENTREKIN
AREA FORECAST DISCUSSION
NWS DENVER/BOULDER CO
528 PM MST TUE DEC 10 2013
.UPDATE...
&&
.SHORT TERM...CRAZY WINDS JUST WON`T GO AWAY AS STRONGER WINDS
HAVE AGAIN INCREASED AGAIN ACROSS BOULDER AND NORTHERN JEFFERSON
COUNTIES. STRONG MOUNTAIN TOP STABILITY AND ENHANCED SUBSIDENCE
COMING DOWN FROM WYOMING SEEM TO BE THE CULPRIT FOR THE INCREASED
WINDS. DON`T EXPECT THE HIGH WINDS TO LAST PAST LATER THIS
EVENING DUE TO A FRONT MOVING INTO THE AREA WHICH WILL CONTINUEDDECREASE
THE SURFACE GRADIENT ACROSS THE STATE AND STRONGEST SUBSIDENCE
MOVE SOUTH OF THE WARNING AREA LATER THIS EVENING. HAVE ISSUED A
SHORT FUSED HIGH WIND WARNING FOR FOOTHILLS AND ADJ PLAINS UNTIL
10 PM THIS EVENING.
.AVIATION...SURFACE WINDS HAVE SHIFTED NORTHEAST AT DENVER AND NOW
JUST SHIFTING NORTHEAST INTO BJC AS THE FRONT MOVES IN. BOULDER
AIRPORT WILL SEE STRONG WINDS IN EXCESS OF 60 MPH UNTIL 8 PM THEN
DECREASING.
&&
.PREV DISCUSSION... /ISSUED 454 PM MST TUE DEC 10 2013/
UPDATE...ONE LAST BIG PUSH OF WIND OCCURRING ALONG THE FOOTHILLS
BEFORE THE WAVE DEPARTS UP TO HIGHER ELEVATIONS AS A COLD FRONTAL
PUSH MOVES IN FROM THE NORTHEAST. THE WINDS SHOULD BE DECREASING
WITHIN THE NEXT COUPLE OF HOURS AS THIS FRONT PUSHES IN. AREAS OF
BLOWING SNOW FROM THE GUSTY WINDS ARE DECREASING VISIBILITIES
ALONG THE FOOTHILLS AND TOWARD THE WYOMING BORDER...CAUSING
HAZARDOUS DRIVING CONDITIONS. THIS WILL BE SUBSIDING DURING THE
EVENING.
AVIATION...THE COLD FRONTAL PUSH OUT ON THE EASTERN PLAINS IS
EXPECTED TO PUSH INTO THE DEN AND APA AIRPORTS TO TURN THE NORTH-
NORTHWESTERLY WINDS AROUND TO THE EAST THEN SOUTH LATER TONIGHT.
BJC WILL CONTINUE BLOWING OUT OF THE WEST WITH GUSTS UP TO 40 MPH
FOR THE NEXT COUPLE HOURS BEFORE DIMINISHING...LIKELY TO LIGHT AND
VARIABLE FOR A SHORT TIME. WINDS STAYING SOUTH-SOUTHWEST THROUGH
18Z WITH LIGHT SPEEDS THEN BECOME SLIGHTLY WESTERLY AGAIN...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.
PREV DISCUSSION... /ISSUED 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...
HIGH WIND WARNING UNTIL 10 PM MST THIS EVENING FOR COZ035-036-
039.
&&
$$
SHORT TERM...ENTREKIN
LONG TERM....COOPER
AVIATION...ENTREKIN
AREA FORECAST DISCUSSION
NWS DENVER/BOULDER CO
454 PM MST TUE DEC 10 2013
.UPDATE...ONE LAST BIG PUSH OF WIND OCCURRING ALONG THE FOOTHILLS
BEFORE THE WAVE DEPARTS UP TO HIGHER ELEVATIONS AS A COLD FRONTAL
PUSH MOVES IN FROM THE NORTHEAST. THE WINDS SHOULD BE DECREASING
WITHIN THE NEXT COUPLE OF HOURS AS THIS FRONT PUSHES IN. AREAS OF
BLOWING SNOW FROM THE GUSTY WINDS ARE DECREASING VISIBILITIES
ALONG THE FOOTHILLS AND TOWARD THE WYOMING BORDER...CAUSING
HAZARDOUS DRIVING CONDITIONS. THIS WILL BE SUBSIDING DURING THE
EVENING.
&&
.AVIATION...THE COLD FRONTAL PUSH OUT ON THE EASTERN PLAINS IS
EXPECTED TO PUSH INTO THE DEN AND APA AIRPORTS TO TURN THE NORTH-
NORTHWESTERLY WINDS AROUND TO THE EAST THEN SOUTH LATER TONIGHT.
BJC WILL CONTINUE BLOWING OUT OF THE WEST WITH GUSTS UP TO 40 MPH
FOR THE NEXT COUPLE HOURS BEFORE DIMINISHING...LIKELY TO LIGHT AND
VARIABLE FOR A SHORT TIME. WINDS STAYING SOUTH-SOUTHWEST THROUGH
18Z WITH LIGHT SPEEDS THEN BECOME SLIGHTLY WESTERLY AGAIN...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.
&&
.PREV DISCUSSION... /ISSUED 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
UPDATE/AVIATION...KRIEDERMAN
AREA FORECAST DISCUSSION
NWS DENVER/BOULDER CO
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...D-L
LONG TERM....GIMMESTAD
AVIATION...D-L
AREA FORECAST DISCUSSION
NWS MOUNT HOLLY NJ
603 PM EST MON DEC 9 2013
.SYNOPSIS...
LOW PRESSURE EAST OF LONG ISLAND IS MOVING NORTHEAST WHILE A NEW
AREA OF LOW PRESSURE FORMS IN NORTH CAROLINA TONIGHT. THAT NORTH
CAROLINA LOW ZIPS NORTHEAST OUT TO SEA TUESDAY AFTERNOON YANKING IN
COLDER AIR BEHIND IT TUESDAY NIGHT. HIGH PRESSURE WILL THEN BUILD
INTO THE REGION FROM THE WEST DURING MID AND LATE WEEK BEFORE
SHIFTING INTO THE WESTERN ATLANTIC SATURDAY. LOW PRESSURE AND A NEW
COLD FRONT ARE SLATED TO MOVE ACROSS THE MID ATLANTIC STATES LATE
SATURDAY. CANADIAN HIGH PRESSURE SHOULD FOLLOW...ARRIVING IN THE
NORTHEAST UNITED STATES EARLY NEXT WEEK.
&&
.NEAR TERM /UNTIL 6 AM TUESDAY MORNING/...
SHORT TERM UPDATE MAINLY ADDRESSED THE MENTION OR LACK THEREOF OF
FOG INTO EARLY THIS EVENING. A WESTERLY GRADIENT OVER OUR CWA HAS
HELPED THIN THE FOG. BASED ON THE LATEST HRRR AND RAP WE PUSHED
BACK THE ONSET OF POPS A COUPLE OF HOURS. WILL TAKE A CLOSER LOOK
AS TO HOW THE MODELS ARE VERIFYING AT 00Z.
WE`LL BE IN A LULL MOST OF TONIGHT, BETWEEN YESTERDAY`S SNOW AND
WHAT`S TO COME TOMORROW. IMPACTS TONIGHT WILL BE ASSOCIATED WITH FOG
AND RESTRICTIVE VISIBILITIES AND SUB-FREEZING TEMPERATURES THAT
COULD REFREEZE WHAT`S CURRENTLY ON THE GROUND.
TEMPERATURES WILL FALL INTO THE LOWER 20S ACROSS THE NORTHWEST ZONES
AND INTO THE UPPER 20S ELSEWHERE.
PRECIPITATION WILL BE REENTERING THE PICTURE TOMORROW MORNING.
THINGS COULD START TO RAMP UP PRIOR TO 6AM. SOUNDINGS SUGGEST ALL
SNOW AT THE ONSET EXCEPT FOR OUR SOUTHERN COUNTIES WHERE SOME
FREEZING RAIN AND SLEET IS POSSIBLE. THE MORNING RUSH COULD BE
IMPACTED, ALTHOUGH IT APPEARS, AT LEAST AT THIS TIME, THAT WHEN YOU
GET NORTH OF DELMARVA, THE ONSET OF PRECIPITATION WILL COMMENCE
DURING THE SECOND HALF OF THE COMMUTE.
&&
.SHORT TERM /6 AM TUESDAY MORNING THROUGH 6 PM TUESDAY/...
WINTER STORM WARNINGS AND WINTER WEATHER ADVISORIES HAVE BEEN
ISSUED. ALTHOUGH BANDING PREDICTABILITY IS FAIRLY LOW, MODELS ARE
POINTING TO THE I95 CORRIDOR AT THIS TIME.
H8-H7 FORCING IS IN PLACE TOMORROW MORNING AS WELL OMEGA. DECENT
SNOW GROWTH IS FORECAST AND WE`RE UNDER THE RIGHT REAR OF THE H3
JET. THE FEELING IS...THERE WILL BE AT LEAST MODERATE SNOW FOR A FEW
HOURS THAT WILL COMPENSATE FOR A DAYTIME SNOWFALL WITH TEMPERATURES
NEAR FREEZING.
WE LIKE 3 TO 5 INCHES ACROSS THE I95 CORRIDOR AND THAT`S WHAT IS IN
THE WSW. OUR GRAPHICS ON THE WEB WILL DISPLAY 4 TO 6 INCHES, WITH 3
TO 5 NOT BEING AN OPTION. LESS AMOUNTS SHOULD FALL ACROSS THE FAR
NORTHWESTERN ZONES, THE FAR SOUTHERN ZONES AND RIGHT ALONG THE COAST.
THE GFS QPF IS ON THE HIGH SIDE OF THE SPECTRUM WHILE THE EURO IS ON
THE LOWER SIDE. WE`RE IN THE MIDDLE.
&&
.LONG TERM /TUESDAY NIGHT THROUGH MONDAY/...
500MB: A BROAD TROUGH IN EASTERN UNITED STATES SHARPENS UP A BIT
THURSDAY AS SHORT WAVES MOVE THROUGH THE BASE OF THE TROUGH. RIDGING
FOLLOWS FRIDAY AND THEN WE WAIT TO SEE HOW THE MID WEEK CLOSED LOW
NEAR BAHA CALIFORNIA INTERACTS WITH THE NORTHERN STREAM FOR NEXT
WEEKEND. LOTS OF UNCERTAINTY IN THE MODELS FOR NEXT WEEKEND WHICH
INCLUDES TEMPS...PTYPE AND STORM TRACK. TROUGHING DEVELOPING IN
THE EASTERN USA MAKES IT PROBABLE THAT SOME SORT OF PRECIPITATION
SHOULD DEVELOP HERE NEXT WEEKEND.
TEMPERATURES: MUCH BELOW NORMAL COLD FOR PORTIONS OF THIS EXTENDED
PERIOD WITH CALENDAR DAY AVERAGE VALUES EXPECTED TO BE 10 DEGREES OR
MORE COLDER THAN NORMAL WEDNESDAY THROUGH FRIDAY AND POSSIBLY AGAIN
NEXT MONDAY WITH FRIDAYS TEMPERATURES POSSIBLY 15 DEGREES BELOW
NORMAL! THE MILDEST DAYS SHOULD BE SATURDAY AND OR SUNDAY.
FORECAST BASIS... TUE NIGHT-WED NIGHT IS A 50 50 BLEND OF THE 12Z/9
GFS/NAM MOS. THURSDAY IS 100 PCT 12Z/9 GFS MOS AND THEN THU NIGHT-
NEXT MONDAY IS THE 1522Z/9 WPC EXTENDED GRIDS. THIS DATA IS CHECKED
AGAINST THE 12Z/9 ECMWF...MODIFIED AND NOTED IN THE DAILIES WHEN
SIGNIFICANT. THE 09Z/9 SREF WAS CHECKED FOR POPS WITHIN ITS FORECAST
RANGE THE 12Z/9 GEFS 6HR POPS FOR .05 WERE CHECKED FOR THE EXTENDED
GRIDS THURSDAY-MONDAY.
THE DAILIES BELOW...
TUE NIGHT...CLEARING AND COLDER WITH FREEZE UP OF THE TUESDAY SNOW
EVENT. WINTRY LOOKING NIGHT-SCAPE. A BIT OF AN ADDED WIND CHILL
TOO!
WEDNESDAY AND THURSDAY...POTENTIAL FOR BURSTS OF SNOW SHOWERS
NEAR AND NORTH OF I80 IN NE PA AND NW NJ AS THE SOUTHERN EXTENT
OF WINDEX EVENTS ARE SUGGESTED BY THE GUIDANCE TO GRAZE THE NORTHERN
PORTION OF OUR FORECAST AREA. THE SHORT WAVES ARE SENDING IN BURSTS
OF COLDER AIR IN GENERAL WNW FLOW AND YOU COULD ARGUE THAT A SECONDARY
COLD FRONTAL PASSAGE CAN OCCUR WEDNESDAY NIGHT. BLUSTERY DAY TIMES.
OVERALL SOUTH OF I80...P/C...POSSIBLY A FLURRY OR 2. THE WCI MAY
DROP TO 10 BELOW ZERO IN THE POCONOS THU NIGHT.
FRIDAY...COLD INTERLUDE WITH INCREASING CLOUDS POSSIBLE?
NEXT WEEKEND...POTENTIAL FOR PERIODS OF WINTRY PCPN...ESPECIALLY
SATURDAY...DEPENDING ON SFC LOW EVOLUTION ON A NEW COLD FRONT
CROSSING EASTWARD FROM THE APPALACHIANS. RIGHT NOW OUR FCST IS
HINGED COMPLETELY ON WPC GUIDANCE. ITS CATEGORICAL THAT IT WILL
PRECIPITATE BUT CONFIDENCE ON DETAILS INCLUDING TEMPS AND PTYPE IS
WELL BELOW AVERAGE.THE FCST DRAWN UP FOCUSES PCPN ON SATURDAY ENDING
SATURDAY EVENING.
NEXT MONDAY...BLUSTERY AND COLD...AT LEAST TO START. THE WCI MAY
DROP TO 10 BELOW IN THE POCONOS EARLY MONDAY BUT CONFIDENCE ON
COLD TEMPS MONDAY IS LESS THAN THE HIGH CONFIDENCE FCST FOR
WEDNESDAY-FRIDAY.
&&
.AVIATION /23Z MONDAY THROUGH SATURDAY/...
THE FOLLOWING DISCUSSION IS FOR KPHL, KPNE, KTTN, KABE, KRDG, KILG,
KMIV, KACY AND SURROUNDING AREAS.
THE FOLLOWING DISCUSSION IS FOR KPHL, KPNE, KTTN, KABE, KRDG, KILG,
KMIV, KACY AND SURROUNDING AREAS.
LATE-DAY...IFR CONDITIONS WILL CONTINUE THROUGH THE REMAINDER OF THE
AFTERNOON. WEST/NORTHWEST WINDS WILL BE LESS THAN 10 KT.
TONIGHT...IFR IS FORECAST TO TRANSITION TO MVFR BEFORE THE NEXT
ROUND OF PRECIPITATION SETTLES INTO THE REGION. NORTHWEST WINDS WILL
BE LESS THAN 10 KT.
TUESDAY...MVFR WILL QUICKLY TRANSITION INTO IFR AS SNOW SETTLES IN
ACROSS THE TERMINALS. A PERIOD OF LIFR IS POSSIBLE IN SOME HEAVIER
SNOW. SOME IMPROVEMENT, MVFR, CAN BE EXPECTED LATER IN THE DAY.
OUTLOOK...
TUESDAY NIGHT...VFR NW WIND GUST TO 20 KT. CONFIDENCE ABOVE AVG.
WEDNESDAY - THURSDAY...VFR SCT-BKN AOA 3500 FT. CHANCE OF A FLURRY
EXCEPT A FEW PERIODS OF MVFR OR IFR CONDS IN SNOW SHOWERS AR
POSSIBLE IN THE POCONOS. W-NW WIND G 20-25 KT EACH AFTN.
CONFIDENCE ABOVE AVERAGE. I DID RAISE 12Z/9 NCEP MOS GUIDANCE BY
ABOUT 4 DEGREES PRIMARILY BECAUSE OF STILL RELATIVELY MILD 850
TEMPS AND THE 12Z/9 UK AND EC 2M TEMPS.
FRIDAY...VFR CIGS. WIND TURNING WEST OR SOUTHWEST IN THE AFTN.
SATURDAY...MVFR OR IFR CONDS PROBABLE IN PCPN.
&&
.MARINE...
TONIGHT...NO HEADLINES WITH DIMINISHING WINDS AND SEAS IN THE 2 TO 4
FOOT RANGE.
TUESDAY...BOTH NORTHWEST WINDS AND SEAS WILL BEGIN TO BUILD LATER
TOMORROW. GUIDANCE SUGGESTS THAT SCA CONDITIONS WILL BE BACK IN
PLACE LATE TOMORROW AFTERNOON OR EARLY TOMORROW EVENING.
OUTLOOK...
TUESDAY NIGHT - THURSDAY...A FAIRLY TIGHT GRADIENT WILL PERSIST WITH
PERIODS OF GUSTY WINDS TO 25 KT AND END OF WESTERLY FETCH SEAS ON
THE ATLANTIC NEAR 5 FT. WE MAY HAVE NEAR GALE FORCE GUSTS TUESDAY
NIGHT AND WEDNESDAY MORNING, ESPECIALLY ACROSS THE NORTHERN OCEAN
WATERS. SCA HAS BEEN STARTED. AN EXTENSION PROBABLE AND IT MAY
NEED AN UPGRADE TO A MARGINAL GALE IN LATER FCST FOR A PTN OF TUE
NIGHT.
FRIDAY...WINDS AND SEAS SHOULD SUBSIDE BELOW SMALL CRAFT ADVISORY
LEVELS AS HIGH PRESSURE BUILDS ACROSS THE REGION AND REMAIN BELOW
AS WE END THE WORK WEEK.
SATURDAY...AN SCA IS POSSIBLE. THERE IS MODEL SPREAD ON THE
SOLUTIONS BUT ITS EVEN POSSIBLE WE`LL NEED A SLY GALE FOR A PTN
OF THE ATLANTIC WATERS. THIS PART OF THE FCST IS VERY LOW
CONFIDENCE.
&&
.PHI WATCHES/WARNINGS/ADVISORIES...
PA...WINTER WEATHER ADVISORY FROM 6 AM TO 5 PM EST TUESDAY FOR
PAZ060>062-101-103-105.
WINTER STORM WARNING FROM 6 AM TO 5 PM EST TUESDAY FOR PAZ070-
071-102-104-106.
NJ...WINTER WEATHER ADVISORY FROM 6 AM TO 5 PM EST TUESDAY FOR
NJZ007>010-012>014-020>027.
WINTER STORM WARNING FROM 6 AM TO 5 PM EST TUESDAY FOR
NJZ015>019.
DE...WINTER WEATHER ADVISORY FROM 6 AM TO 5 PM EST TUESDAY FOR
DEZ002>004.
WINTER STORM WARNING FROM 6 AM TO 5 PM EST TUESDAY FOR DEZ001.
MD...WINTER WEATHER ADVISORY FROM 6 AM TO 5 PM EST TUESDAY FOR
MDZ012-015-019-020.
WINTER STORM WARNING FROM 6 AM TO 5 PM EST TUESDAY FOR MDZ008.
MARINE...SMALL CRAFT ADVISORY FROM 5 PM TUESDAY TO 6 AM EST WEDNESDAY
FOR ANZ430-431-450>455.
&&
$$
SYNOPSIS...DRAG
NEAR TERM...GIGI/KRUZDLO
SHORT TERM...KRUZDLO
LONG TERM...DRAG
AVIATION...DRAG/KRUZDLO
MARINE...DRAG/KRUZDLO
AREA FORECAST DISCUSSION
NWS MELBOURNE FL
830 PM EST TUE DEC 10 2013
.DISCUSSION...
CURRENT-OVERNIGHT...COLD FRONT SLOWLY WORKING ITS WAY OVER AREAS
FROM INTERSTATE 4 NORTH IN CENTRAL FLORIDA. WEATHER RADAR LOOPS
SHOWING A WEAKENING LINE OF SHOWERS WITH AREAS OF SHOWERS AHEAD OF
THE FRONT THAT WERE FORMED BY EARLIER OUTFLOW WINDS MOVING ACROSS
AREAS NORTH OF INTERSTATE 4 AND ORLANDO. THE LATEST RUC ANALYSIS OF
THE JET STREAM AND VORTICITY SUGGEST THAT THERE IS LITTLE MID AND
UPPER LEVEL SUPPORT FOR SIGNIFICANT WEATHER. HOWEVER...WITH THE JET
AXIS NORTH OF CENTRAL FLORIDA AND WEAK IMPULSES MOVING QUICKLY
OVERHEAD EAST CENTRAL FLORIDA MID AND UPPER LEVEL CLOUDINESS SHOULD
REMAIN IN PLACE OVERNIGHT. CURRENT FORECAST OF A SLIGHT CHANCE OF
RAIN FROM ORLANDO NORTH AND SPRINKLES FROM SOUTH OF ORLANDO INTO
INDIAN RIVER AND OSCEOLA COUNTIES LOOKS OK AS THE WEAKENING FRONT
CONTINUES TO WORK ITS WAY DOWN THE FLORIDA PENINSULA. WINDS HAVE
ALREADY VEERED TO THE NORTH AT THE METAR SITES NORTH OF ORLANDO AND
WILL CONTINUE TO SHIFT TO NORTH THEN NORTHEAST OVER CENTRAL AND
SOUTHERN AREAS OVERNIGHT.
PREVIOUS ZONES DISCUSSION
CURRENT-TONIGHT...WEAK FRONTAL BOUNDARY PUSHING THROUGH NORTH
FLORIDA THIS AFTERNOON AND SHOULD MAKE AN APPEARANCE INTO CENTRAL
FLORIDA EARLY THIS EVENING. IT IS FORECAST TO STALL OVERNIGHT OVER
OUR SOUTHERN COUNTIES. THE OVERALL ATMOSPHERIC PROFILE IS FAIRLY DRY
THROUGH CENTRAL FLORIDA SO PRECIPITATION CHANCES WILL REMAIN 20
PERCENT OR LESS OVER THE AREA. ONLY A SPRINKLE OR BRIEF LIGHT SHOWER
WILL ACCOMPANY THE BOUNDARY. MID-LEVEL SHORTWAVE ENERGY REMAINS
OVERALL ABSENT ACROSS THE AREA. SOUTHWESTERLY WINDS WILL GRADUALLY
VEER THIS EVENING AND OVERNIGHT IN RESPONSE TO THE FRONT TOWARD THE
NORTHWEST/NORTH AND EVENTUALLY NORTH-NORTHEAST BY SUNRISE WED
MORNING. EXPECTING A BACKING OF WINDS TO THE EAST-SOUTHEAST LATER
THIS AFTERNOON FROM NEAR MELBOURNE SOUTHWARD DUE TO EAST COAST SEA
BREEZE FORMATION BUT INLAND PUSH WILL BE SLOWED BY SOUTHWEST FLOW
ABOVE THE SURFACE.
THE PRE FRONTAL SOUTHWEST FLOW HAS ALLOWED ONE RECORD TO FALL
ALREADY THIS AFTERNOON...MELBOURNE HAS HIT 85 DEGREES. THE OLD
RECORD OF 84 DEGREES WAS SET LAST YEAR ON THIS DATE.
NORTHERLY WINDS BEHIND THE FRONT TONIGHT WILL BRING IN SOME DRIER
AND SLIGHTLY COOLER AIR MAINLY TO THE NORTH HALF BUT EXPECT
CONSIDERABLE CLOUDINESS AS THE SHALLOW COOL AIR UNDERCUTS THE PRE
FRONTAL MOIST LAYER. EXPECT OVERNIGHT LOWS IN THE MIDDLE TO UPPER
50S NORTH OF THE I-4 CORRIDOR WITH 60S STILL FORECAST FURTHER
SOUTHWARD.
WED...THE QUASI-STATIONARY BOUNDARY OVER OUR SOUTHERN COVERAGE
WARNING AREA WILL CONTINUE TO WEAKEN AND WASH OUT THROUGH LATE DAY.
STRONG HIGH PRESSURE WILL SETTLE INTO THE CENTRAL PLAINS AND UPPER
MIDWEST AS A REINFORCING FRONTAL BOUNDARY MOVES INTO THE MISSISSIPPI
VALLEY BY LATE DAY. LINGERING MOISTURE AND WEAK FRONTAL CONVERGENCE
WILL ALLOW FOR LOW CHANCES OF SPRINKLES AND LIGHT RAIN SHOWER
ACTIVITY ACROSS THE AREA. WILL CONTINUE TO KEEP POPS MAINLY 20
PERCENT OR LESS OVER EAST CENTRAL FLORIDA.
THE RESULTING WEAK COOL AIR ADVECTION WILL BE SUFFICIENT TO PUSH MAX
TEMPERATURES BACK A FEW DEGREES FROM PREVIOUS DAY`S HIGHS. THE
DEVELOPING ONSHORE FLOW AND INCREASING MID/UPR LVL CLOUD COVER WILL
KEEP AFTERNOON TEMPERATURES IN THE MID TO UPPER 70S ALONG AND NORTH
OF THE I-4 CORRIDOR WITH NEAR 80 DEGREES TO LOWER 80S SOUTHWARD.
WED NIGHT-FRI NIGHT...REINFORCING COLD SURFACE HIGH WILL MOVE ESE
AND PUSH A REINFORCING COLD FRONT AND STRONG N-NE WIND SURGE THROUGH
FL EARLY THU. THIS RESULTS IN CONTINUATION OF THE MODIFIED COOL/DRY
ADVECTION PATTERN THROUGH THU NIGHT. HIGH MOVES BODILY EWD ON FRI...
WITH WINDS VEERING TO EAST FRI AND THEN WEAKENING OUT OF THE ESE
BY FRI NIGHT.
CAA PATTERN ON STRONG/GUSTY N-NE WINDS WILL HOLD MAX TEMPS BACK INTO
THE 70S (NEAR 80F AROUND KOBE) WITH MINS DROPPING INTO THE L-M50S
N/W OF LAKE KISM-TIX...AND L60S ALONG THE IMMEDIATE TREASURE COAST
(A FEW DEGS WARMER ALONG THE BARRIER ISLANDS)
SAT-TUE (PREVIOUS) PROGRESSIVE WX PATTERN INTO EARLY NEXT WEEK AS
ADDITIONAL JET IMPULSES OVER THE PACIFIC WORK THEIR WAY ACRS THE
CONTINENT AND CONTINUE TO FEED THE STRONG H30-H20 JET OVER THE ERN
CONUS. AS THE POST FRONTAL RIDGE BUILDS INTO THE W ATLC...WINDS WILL
VEER TO THE S/SE ON SAT...THEN TO THE W/SW SAT NIGHT...ALLOWING
TEMPS TO WARM BACK ABV CLIMO WHERE THEY WILL STAY FOR MUCH OF THE
WEEKEND. LATEST RUNS OF THE GFS AND ECMWF HAVE COME INTO CLOSER
ALIGNMENT WITH THE NEXT STORM SYSTEM...BOTH INDICATING IT TAKING A
MORE NRLY TRACK TOWARD THE GREAT LAKES/NEW ENGLAND REGION OVER THE
WEEKEND. GFS IS A FASTER WITH THE FROPA THRU CENTRAL FL AND A LITTLE
MORE AGGRESSIVE WITH THE POST FRONTAL DRYING/COOLING. REGARDLESS...
WEEKEND WX WILL SEE THE HIGHEST POPS FOR THIS FCST PACKAGE WITH
TEMPS NEAR OR ABV AVG.
&&
.AVIATION...
CURRENT-OVERNIGHT...NORTHERLY WINDS SHIFTING TO THE NORTHEAST LATE
OVERNIGHT AND MVFR CEILINGS AS THE WEAKENING BOUNDARY MOVES DOWN
THE PENINSULA
PREVIOUS AVIATION DISCUSSION
SOUTHWESTERLY FLOW WILL VEER BEHIND AN APPROACHING FRONT
THIS EVENING TO NW/N AND EVENTUALLY NNE BY SUNRISE WED MORNING. THE
FRONT WILL SETTLE OVER SOUTH-CENTRAL FL OVERNIGHT AND WASH OUT
ACROSS THE AREA DURING THE DAY ON WED. VFR CONDITIONS WILL CONTINUE
INTO THIS EVENING THOUGH CLOUD CEILINGS WILL BEGIN TO LOWER
OVERNIGHT INTO THE DAY ON WED. MVFR CIGS POSSIBLE OVERNIGHT MAINLY
KISM-KMCO-KTIX NORTHWARD IN ASSOCIATION WITH THE BOUNDARY. ONLY AN
ISOLD THREAT FOR A SPRINKLE OR BRIEF LIGHT SHOWER OVER THE NEXT 24
HOURS WITH THE FRONT.
&&
.MARINE...
CURRENT-OVERNIGHT...BUOY 009 20NM EAST OF CAPE CANAVERAL WAS
RECORDING SOUTHERLY WINDS AROUND 10 KNOTS AND 3 FOOT LONG PERIOD
SEAS. THE BUOY 42NM EAST OF SAINT AUGUSTINE WAS RECORDING NORTHERLY
WINDS AROUND 20 KNOTS AND SEAS TO 3 FEET. THE TWO SCRIPPS BUOYS WERE
RECORDING 2 FOOT LONG PERIOD SEAS. SEAS BUILD TO AROUND 6 FEET IN
THE GULF STREAM DOWN TO SEBASTIAN INLET OVERNIGHT AS THE NORTHERLY
WINDS AT 15 TO 20 KNOTS WORK THEIR WAY DOWN THE COASTAL WATERS AND
IMPACT THE GULF STREAM.
PREVIOUS MARINE DISCUSSION
CURRENT-TONIGHT...A FRONTAL BOUNDARY IS MOVING THROUGH
NORTH FL THIS AFTERNOON AND WILL MAKE IT INTO CENTRAL FL DURING THE
EARLY EVENING. IT WILL MAKE FURTHER PROGRESS SOUTHWARD OVERNIGHT AND
STALL OVER THE SOUTHERN COASTAL WATERS LATE. THE PRESSURE GRADIENT
WILL INCREASE SLIGHTLY AGAIN TONIGHT GRADUALLY TRANSITIONING TO
NW/N/NNE THIS EVENING BEHIND THE BOUNDARY EVENTUALLY BECOMING
NORTHEAST BY DAYBREAK WED MORNING...AT LEAST NORTH OF SEBASTIAN
INLET. WIND SPEEDS WILL INCREASE BEHIND THE BOUNDARY UP TO 15-20 KTS
NORTH OF SEBASTIAN INLET WHERE SMALL CRAFT SHOULD EXERCISE CAUTION
TONIGHT. SEAS 3-5 FT THIS AFTERNOON WILL BUILD TO 4-6 FT AFTER
MIDNIGHT AWAY FROM THE COAST AND NORTH OF SEBASTIAN INLET. ISOLD
LIGHT SHOWERS WILL DEVELOP THIS EVENING IN VICINITY OF FRONT.
THE EAST COAST SEA BREEZE BOUNDARY HAS DEVELOPED ALONG THE TREASURE
COAST AND MAY FORM AS FAR NORTH AS MELBOURNE THROUGH LATE AFTERNOON
BUT INLAND PROGRESSION WILL BE RETARDED BY THE DEEPER SOUTHWESTERLY
FLOW. WHERE THE SEA BREEZE DEVELOPS WINDS WILL BACK TO THE
EAST-SOUTHEAST ALONG THE IMMEDIATE COAST.
WED...THE FRONTAL BOUNDARY WILL CONTINUE TO WEAKEN AND WASH OUT OVER
THE SOUTHERN COASTAL WATERS DURING THE DAY. THIS WILL CAUSE THE
PRESSURE GRADIENT TO RELAX WITH NORTHEAST WIND SPEEDS FALLING TO
10-15 KTS...AND LOWER IN THE AFTERNOON SOUTH OF THE CAPE. CAUTIONARY
STATEMENTS MAY BE NECESSARY VERY EARLY IN THE PERIOD BUT WILL ALLOW
FUTURE SHIFTS TO MAKE THAT CALL...AS SEAS MAY STILL BUILD TO 4-6 FT
AWAY FROM THE COAST.
THU-FRI (PREV)...NEWLY MERGED SFC RIDGE WILL MOVE STEADILY ACRS THE
APPALACHIAN THRU THE DAY AND APPROACH THE MID ATLC COAST OVERNIGHT.
TIGHTENING PGRAD WILL ALLOW WINDS TO FRESHEN OUT OF THE N AFTER
DAYBREAK TO 20-25KTS...THEN GRADUALLY VEER TO THE NE AFT SUNSET.
SEAS BUILDING TO 5-7FT BY AFTN...THEN 6-8FT NEARSHORE AND 8-10FT
OFFSHORE OVERNIGHT. A MODERATE-FRESH E/NE BREEZE ON FRIDAY VEERS TO
SE OVERNIGHT AS THE HI PRES RIDGE PUSHES OFF THE MID ATLC COAST AND
SLOWLY WEAKENS OVER THE W ATLC. SEAS WILL GRADUALLY SUBSIDE AS WINDS
DIMINISH...BUT OVERALL CONDITIONS WILL REMAIN ROUGH. SEAS 6-8FT
NEARSHORE AND 8-10FT OFFSHORE THRU THE DAY...DECREASING TO 4-6FT
NEARSHORE AND 6-8FT OFFSHORE OVERNIGHT.
SAT-SUN...MODERATE TO FRESH S/SE BREEZE THRU THE DAY WILL VEER TO
THE SW ON SAT AND WSW SAT NIGHT AS THE NEXT STORM SYSTEM SPINS UP
AND PULLS A COLD FRONT THROUGH THE GOMEX AND SERN CONUS. THE 12Z
GFS/ECM ARE IN BETTER AGREEMENT ON SUN NIGHT TIMING OF FROPA...
HOWEVER THE GFS SHOWS STRONGER POST-FRONTAL WINDS/CAA REACHING ECFL
EARLIER. DVLPG OFFSHORE WIND COMPONENT SAT WILL ALLOW SEAS TO
DIMINISH TO 2-4FT NEARSHORE AND 4-5FT OFFSHORE. HOWEVER...WINDS WILL
BE STRONG ENOUGH TO GENERATE CHOPPY SHORT PERIOD WIND WAVES WITHIN A
FEW MILES OF SHORE. WIND SHIFT TO NRLY LATE SUN AND N-NE SUN NIGHT.
&&
.CLIMATE...
RECORD HIGH TEMPS TODAY...
DAB 85 SET IN 1947
MCO 88 SET IN 1918
MLB 84 SET IN 2012 (NOW 85 SET TODAY)
VRB 86 SET IN 2012
&&
.MLB WATCHES/WARNINGS/ADVISORIES...
FL...NONE.
AM...NONE.
&&
$$
FORECASTS...WIMMER
IMPACT WX...KELLY
AREA FORECAST DISCUSSION
NWS MIAMI FL
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.
&&
.AVIATION...
MAINLY VFR CONDITIONS EXPECTED TO PREVAIL THROUGH THE AFTERNOON
AND EVENING HOURS. A MODERATE SOUTHEASTERLY FLOW WILL PREVAIL
ACROSS THE REGION TONIGHT INTO TUESDAY. IN INCREASE IN MOISTURE IS
EXPECTED TUESDAY MORNING WITH A CHANCE OF SHOWERS POSSIBLE LATE
TUESDAY AND NOT INCLUDED IN THIS TAF ISSUANCE.
&&
.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 71 82 70 82 / 10 20 20 30
FORT LAUDERDALE 72 82 71 82 / 10 40 30 30
MIAMI 72 82 72 83 / 10 40 30 30
NAPLES 67 81 67 82 / 0 20 20 30
&&
.MFL WATCHES/WARNINGS/ADVISORIES...
FL...NONE.
AM...NONE.
GM...NONE.
&&
$$
DISCUSSION/MARINE/FIRE...13/SI
AVIATION/RADAR...60/BD
AREA FORECAST DISCUSSION
NWS COLUMBIA SC
759 AM EST MON DEC 9 2013
.SYNOPSIS...
SURFACE WEDGE FLOW WILL BEGIN TO BREAK DOWN TODAY AHEAD OF ANOTHER
APPROACHING COLD FRONT. THIS COLD FRONT WILL SLOWLY MOVE THROUGH
LATE TONIGHT AND INTO TUESDAY...AND STALL JUST TO OUR SOUTH
WEDNESDAY. DRY HIGH PRESSURE IS EXPECTED TO RETURN THE MID TO LATE
WEEK...WITH ANOTHER SYSTEM ARRIVING NEXT WEEKEND.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
CONFIDENCE IS INCREASING FOR WEDGE TO HOLD ACROSS THE REGION
THROUGH THE DAY. LATEST HOURLY RAP TEMPERATURE DATA SUPPORTS LOCAL
WEDGE SCHEME AND KEEPS COLD AIR IN PLACE. STRONG SOUTH LOW LEVEL
FLOW IN THE BOUNDARY LAYER ISENTROPIC LIFT RESULTING DRIZZLE AT
TIMES...BUT WARM FRONT PROBABLY REMAINS TO THE SOUTH OF THE
REGION. SO LOWERED TEMPERATURES AGAIN SEVERAL DEGREES...
STRONGEST ISENTROPIC LIFT ACROSS PIEDMONT/NORTH MIDLANDS...SO
EXPECT HIGHER CHANCE RAIN IN THAT REGION...LOWER CHANCE SOUTHEAST
MIDLANDS/CSRA.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH TUESDAY NIGHT/...
CHANCES FOR RAIN WILL INCREASE DURING THE OVERNIGHT PERIOD AS THE
AXIS OF HIGHER PRECIPITABLE WATER VALUES AND MOISTURE TRANSPORT
GRADUALLY SHIFT EASTWARD AHEAD OF AN APPROACHING COLD FRONT. WILL
CONTINUE THE GRADIENT IN POPS FROM LIKELY NORTHWEST TO LOW CHANCE
IN THE SOUTHEASTERN PART OF THE FORECAST AREA.
FAST MOVING SHORTWAVE ENERGY WILL PUSH EASTWARD INTO THE TENNESSEE
AND OHIO VALLEYS LATE TONIGHT INTO TUESDAY WHICH WILL PUSH THE
COLD FRONT ACROSS THE FORECAST AREA LATE TUESDAY MORNING INTO
TUESDAY AFTERNOON. POOLING OF MOISTURE ON THE FRONT IS EXPECTED
WITH PRECIPITABLE WATER VALUES RISING TO AROUND 1.5 INCHES. A
STRONG 50 KT LOW LEVEL JET IS FORECAST TO PRECEDE THE FRONT WHILE
SHIFTING ACROSS THE REGION AND COMBINING WITH INCREASED LOW LEVEL
CONVERGENCE AND INCREASING UPPER FORCING AS THE FORECAST AREA
FALLS WITHIN THE RIGHT ENTRANCE REGION OF THE UPPER JET. THEREFORE
WILL TRANSITION LIKELY POPS ACROSS THE FORECAST AREA TUESDAY FROM
WEST TO EAST WITH A SHARP DECREASE IN POPS LATE TUESDAY AFTERNOON
AS THE UPPER FLOW BECOMES MORE ZONAL WHICH WILL PUSH THE FRONT EAST
OF THE AREA WITH DRIER AIR WORKING IN FROM THE WEST. TEMPERATURES
WILL REBOUND TO ABOVE NORMAL VALUES AHEAD OF THE FRONT WITH STRONG
MIXING OF WARMER AIR ALOFT DOWN TO THE SURFACE.
SKIES WILL CLEAR FROM WEST TO EAST TUESDAY AFTERNOON AND NIGHT AS
LOW LEVEL FLOW BECOMES NORTHWESTERLY AS SURFACE HIGH PRESSURE
BUILDS OVER THE AREA USHERING IN MUCH DRIER AIR TO THE REGION.
COLD ADVECTION TUESDAY NIGHT WILL ALLOW LOW TEMPERATURES TO FALL
INTO THE 30S ACROSS THE REGION.
&&
.LONG TERM /WEDNESDAY THROUGH SUNDAY/...
MEDIUM RANGE MODELS HAVE COME INTO BETTER AGREEMENT IN KEEPING THE
STALLED FRONTAL BOUNDARY JUST TO OUR SOUTH ON WEDNESDAY AND
CONFINING ANY ADDITIONAL PRECIPITATION ASSOCIATED WITH AN INVERTED
TROUGH OFF THE COAST THROUGH WEDNESDAY NIGHT SOUTH AND EAST OF THE
FORECAST AREA. WILL KEEP DRY FORECAST WEDNESDAY THROUGH FRIDAY AS
PRECIPITABLE WATER VALUES REMAIN BELOW 0.5 INCHES. TEMPERATURES
WILL BE BELOW NORMAL WEDNESDAY THROUGH FRIDAY WITH COOL HIGH
PRESSURE SETTLED OVER THE SOUTHEAST.
UNSETTLED WEATHER IS EXPECTED TO RETURN BY THE WEEKEND WITH GFS
AND ECMWF COMING INTO BETTER AGREEMENT. A CUT OFF UPPER LOW OVER
THE FOUR CORNERS REGION ON FRIDAY WILL OPEN UP AND PHASE WITH A
DIGGING NORTHERN STREAM TROUGH OVER THE CENTRAL PLAINS AND
MISSISSIPPI VALLEY BY FRIDAY NIGHT. MOISTURE WILL INCREASE QUICKLY
AHEAD OF THE APPROACHING SYSTEM FRIDAY NIGHT WITH SOUTHERLY LOW
LEVEL FLOW WITH RAIN EXPECTED TO OVERSPREAD THE REGION BY SATURDAY
AS THE TROUGH MOVES EASTWARD INTO THE MID ATLANTIC REGION. WILL
KEEP CHANCE POPS FRIDAY NIGHT BUT HAVE INCREASED POPS TO LIKELY
FOR SATURDAY...AND HOLD ON TO CHANCE POPS SUNDAY WITH LOW
CONFIDENCE IN THE EVENTUAL SPEED OF THIS SYSTEM. DO NOT EXPECT ANY
PRECIP TYPE ISSUES DESPITE SOME INITIALLY DRY AIR TO OVERCOME.
TEMPERATURES SAT/SUN SHOULD CONTINUE TO BE NEAR OR BELOW NORMAL.
&&
.AVIATION /13Z MONDAY THROUGH FRIDAY/...
STRONG WEDGE CONDITIONS CONTINUE ACROSS THE AREA THIS MORNING.
ALL TAF SITES REMAIN IFR/LIFR DUE TO CEILINGS AND SOME FOG AND
DRIZZLE. MODEL TIME SECTIONS CONTINUE TO SHOW ABUNDANT LOW LEVEL
MOISTURE THROUGH THE TAF PERIOD. MODELS STILL TRY TO HOLD ON TO
THE WEDGE THROUGH MIDDAY. WILL KEEP LOW CONDITIONS IFR/LIFR FOR
MUCH OF THE PERIOD...BECOMING MVFR BY THE AFTERNOON. LATEST
GUIDANCE CONTINUES TO SHOW CONDITIONS DROPPING ONCE AGAIN TO
IFR/POSSIBLE LIFR AFTER 00Z TUESDAY.
EXTENDED AVIATION OUTLOOK..A COLD FRONT WILL SLOWLY MOVE THROUGH
THE AREA TUESDAY. THERE WILL BE A CHANCE OF SHOWERS AND ASSOCIATED
RESTRICTIONS WITH THE FRONT. THE FRONT IS FORECAST TO STALL JUST
TO OUR SOUTH WEDNESDAY WITH HIGH PRESSURE BUILDING EASTWARD TO OUR
NORTH. A RETURN TO VFR CONDITIONS POSSIBLE WEDNESDAY...BUT
CONFIDENCE IS LOW. BY THURSDAY...HIGH PRESSURE BEGINS TO DOMINATE
THE AREA AND VFR CONDITIONS ARE MORE CONFIDENT.
&&
.CAE WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
GA...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS CHARLESTON SC
623 AM EST MON DEC 9 2013
.SYNOPSIS...
A WARM FRONT WILL LIFT NORTH THROUGH THE AREA TODAY...THEN A COLD
FRONT WILL MOVE INTO THE REGION FROM THE NORTHWEST TUESDAY. HIGH
PRESSURE WILL BUILD FROM THE WEST DURING THE MID TO LATE WEEK
PERIOD. ANOTHER FRONTAL SYSTEM WILL IMPACT THE REGION DURING THE
WEEKEND.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
FOR THE SUNRISE UPDATE...DENSE FOG IS SPREADING INLAND SO THE
DENSE FOG ADVISORY WILL BE RETAINED. LATEST RAP AND NAM-WRF DATA
SUGGEST THE CAD WILL BE SLOWER TO ERODE THAN EXPECTED AND SHOWS
HIGHS WELL INLAND STRUGGLING TO REACH THE MID 60S. HAVE OPTED TO
LOWER HIGHS BY A CATEGORY INTO THE UPPER 60S ACROSS THE FAR
INTERIOR ROW OF ZONES AND IF THE H3R PROVES CORRECT...THEN FAR
INLAND AREAS STRETCHING BACK INTO THE CHARLESTON METRO AREA WILL
ONLY PEAK IN THE LOWER-MID 60S. OBVIOUSLY THERE IS A BIG BUST
POTENTIAL FOR THE TEMPERATURE FORECAST FOR TODAY...NOT UNCOMMON
FOR CAD EROSION.
IMPRESSIVE COLD AIR DAMMING /CAD/ REMAINS IN PLACE THIS MORNING
WITH WIDESPREAD FOG...LOW CEILINGS AND INTERMITTENT DRIZZLE.
PRESSURE FALLS ARE BEGINNING TO INCREASE ACROSS THE CORE OF THE
CAD REGION PER 09/09Z ISALLOBARIC ANALYSIS SUGGESTING THE WEDGE
IS BEGINNING TO STEADILY WEAKEN. AREA WEBCAMS AND SURFACE
OBSERVATIONS SHOW STRATUS BUILD DOWN IS OCCURRING WHICH SHOULD
TRANSLATE TO WIDESPREAD DENSE FOG PRIOR TO SUNRISE AS CEILINGS
REACH THE GROUND. THE ONLY CONCERN IS THAT SURFACE WINDS ARE
RUNNING A TAD HIGHER THAN EXPECTED...WHICH MAY LIMIT VISIBILITIES
SOMEWHAT...BUT WINDS ARE FORECAST TO DROP OFF OVER THE NEXT FEW
HOURS. A DENSE FOG ADVISORY REMAINS IN EFFECT FOR ALL ZONES UNTIL
10 AM. FOG MAY LINGER ALONG THE BEACHES A BIT LONGER WITH FOG
LIKELY REMAINING TRAPPED UNDERNEATH A STRONG MARINE INVERSION.
AS COLD AIR DAMMING BREAKS DOWN...A WARM FRONT WILL MOVE STEADILY
NORTH TODAY ALLOWING A SIGNIFICANT RECOVERY IN TEMPERATURES FOR
ALL AREAS. HIGHS IN THE MID-UPPER 70S LOOK QUITE REASONABLE GIVEN
THE AMOUNT OF WARM AIR NOTED ATOP THE COLD AIR WEDGE. ISOLATED TO
SCATTERED SHOWERS LOOK TO INCREASE LATER THIS AFTERNOON AS WARM
AIR ADVECTION AND LOW-LEVEL JETTING INTENSIFY AHEAD OF AN
APPROACHING COLD FRONT. POPS WILL BE LIMITED TO 20-30
PERCENT...HIGHEST ACROSS THE FAR WESTERN AREAS.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH THURSDAY/...
TONIGHT...ONGOING WARM AIR ADVECTION AND LOW-LEVEL JETTING WILL
KEEP TEMPERATURES RATHER MILD FOR DECEMBER WITH LOWS IN THE
LOWER-MID 60S...EXCEPT UPPER 50S ACROSS PORTIONS OF ALLENDALE-
SCREVEN-JENKINS COUNTIES. RAIN CHANCES WILL REMAIN RATHER STATIC
FOR MUCH OF THE NIGHT...WITH POPS 20-30 PERCENT...BUT WILL BEGIN
TO RAMP UP CLOSER TO 40 PERCENT ACROSS THE FAR WEST JUST BEFORE
SUNRISE TUESDAY. MORE FOG WILL BE POSSIBLE AFTER MIDNIGHT...BUT
CURRENT INDICATIONS ARE THAT THE FOG WILL NOT BE DENSE. THE ONLY
EXCEPTION COULD BE ALONG THE COAST IF SEA FOG IMPACTS COASTAL
COMMUNITIES.
TUESDAY...A COLD FRONT WILL PROGRESS THROUGH THE FORECAST AREA
DURING THE DAYTIME HOURS AND LIKELY BE OFFSHORE BY SUNSET. WILL
CONTINUE TO INDICATE THE BEST RAIN POTENTIAL OF THE PERIOD
TUESDAY...WITH POPS UP TO 50 PERCENT AS THE FRONTAL ZONE CROSSES
SOUTHEAST SOUTH CAROLINA AND SOUTHEAST GEORGIA. CONSIDERING GOOD
AGREEMENT IN NUMERICAL MODEL SOLUTIONS...SUBSEQUENT FORECAST
ISSUANCES MAY BE ABLE TO RAISE RAIN CHANCES EVEN HIGHER INTO THE
LIKELY CATEGORY. THE WARMING EFFECTS OF PRE-FRONTAL COMPRESSION...AS
WELL AS PERSISTENT SOUTHWEST/WEST FLOW THROUGH THE AFTERNOON...WILL
SUPPORT HIGH TEMPERATURES ABOVE SEASONAL NORMALS IN THE UPPER 60S
WEST TO LOWER 70S EAST. SHOWER COVERAGE WILL QUICKLY DIMINISH FROM
WEST TO EAST IN THE WAKE OF THE DEPARTING COLD FRONT AFTER
SUNSET...AND WITH COLD ADVECTION QUICKLY INITIATING...EXPECT
TEMPERATURES TO RAPIDLY FALL DURING THE EVENING AND OVERNIGHT HOURS.
LOW TEMPERATURES WILL RANGE FROM THE UPPER 30S INLAND TO THE MID 40S
NEAR THE COAST AND SOUTH OF INTERSTATE 16.
WEDNESDAY...THE INITIAL AREA OF SURFACE HIGH PRESSURE BUILDING IN
THE WAKE OF THE COLD FRONT WILL ACTUALLY DIMINISH AS THE DAY
PROGRESSES...TO BE REPLACED BY A NOTABLY STRONGER SURFACE HIGH
FOLLOWING SHORTWAVE ENERGY WITHIN BROAD UPPER TROUGHING. NORTHEAST
FLOW WILL STILL CONTINUE WITHIN THIS TRANSITIONING PATTERN AND
SUPPORT A SIGNIFICANT COOLING TREND. EXPECT HIGH TEMPERATURES TO
BE SUPPRESSED IN THE MID 50S NORTH TO THE LOW 60S FAR
SOUTH...WHILE LOW TEMPERATURES REACH SIMILAR VALUES TO THE
PREVIOUS NIGHT. SOME CONVERGENCE OVER THE NEARBY ATLANTIC WATERS
AND ALONG THE PERIPHERY OF THE BUILDING SURFACE HIGH COULD ALSO
SUPPORT ISOLATED TO SCATTERED SHOWER ACTIVITY OVER THE MARINE
ZONES. HAVE MAINTAINED A CORRIDOR OF SLIGHT CHANCE POPS ACROSS THE
EASTERN THIRD OF THE FORECAST AREA TO ACCOUNT FOR A SMALL
POTENTIAL OF SOME INLAND SHOWER INTRUSION.
THURSDAY...THE AMPLIFYING SHORTWAVE TROUGH WILL QUICKLY SLIP OFF
THE EAST COAST...WHILE THE STRONGER DRY HIGH PRESSURE BUILDS OVER
THE MID ATLANTIC STATES AND CAROLINAS. ANOTHER WAVE OF COLD
ADVECTION WILL KEEP TEMPERATURES WELL BELOW SEASONAL NORMALS ONCE
AGAIN...WITH HIGHS PEAKING ONLY IN THE 50S DESPITE SCATTERING SKY
COVER AND IMPROVED INSOLATION. RAIN CHANCES WILL REMAIN BELOW 15
PERCENT THROUGH THE DAY.
&&
.LONG TERM /THURSDAY NIGHT THROUGH SUNDAY/...
SURFACE HIGH PRESSURE WILL STEADILY TRACK OFF THE COAST AND INTO
THE ATLANTIC WATERS THROUGH FRIDAY...AHEAD OF SOUTHERN STREAM
SHORTWAVE ENERGY LIFTING INTO THE TENNESSEE VALLEY. MEDIUM RANGE
MODELS REMAIN IN NOTABLE DISAGREEMENT REGARDING THE STRENGTH AND
TRACK OF SYNOPTIC SCALE FEATURES ON SATURDAY...WITH THE GENERAL
CONSENSUS BEING VARIATIONS OF A FRONTAL SYSTEM CROSSING THE
FORECAST AREA ON SATURDAY. COOL TEMPERATURES AND RAIN-FREE
CONDITIONS WILL CONTINUE FOR THE DAYTIME HOURS ON FRIDAY...BEFORE
RAIN CHANCES QUICKLY INCREASE FROM WEST TO EAST FRIDAY NIGHT AND
PEAK SATURDAY AFTERNOON. TEMPERATURES ON SATURDAY COULD BE A FEW
DEGREES WARMER THAN PREVIOUS DAYS...BUT MUCH DEPENDS ON THE SPEED
WITH WHICH THE FRONT MOVES THROUGH THE FORECAST AREA. ONCE THE
COLD FRONT SHIFTS OFFSHORE BY SUNDAY MORNING...THE ASSOCIATED
SURFACE LOW TO THE NORTH WILL INTENSIFY RAPIDLY OFF THE NEW
ENGLAND COAST. THE SOUTHEAST STATES WILL ONCE AGAIN BECOME LOCATED
WITHIN DRIER HIGH PRESSURE BEHIND THE DEPARTING COLD FRONT...WITH
RAIN CHANCES EXPECTED TO STEADILY DECREASE SUNDAY. TEMPERATURES
WILL UNDERGO ANOTHER COOLING TREND FOR SUNDAY AND MONDAY.
&&
.AVIATION /11Z MONDAY THROUGH FRIDAY/...
LIFR CONDITIONS PERSIST AT BOTH TERMINALS WITH CIGS/VSBYS AT
AIRFIELD MINIMUMS. LIFR CONDITIONS WILL PERSIST THROUGH MID-
MORNING BEFORE SLOWLY LIFTING AS COLD AIR DAMMING BREAKS DOWN AND
A WARM FRONT MOVES NORTH. THERE IS MUCH UNCERTAINTY ON THE EXACT
TIMING OF WHEN CONDITIONS WILL RISE ABOVE IFR AND MVFR
THRESHOLDS...BUT CURRENT THINKING FOR KCHS IS 16Z FOR IFR AND
1730Z FOR MVFR. AT KSAV...EXPECT LIFR THROUGH 15Z AND MVFR THROUGH
1630Z. VFR FOR LATE MORNING INTO THE AFTERNOON. LOW CLOUDS AND FOG
ARE POSSIBLE AGAIN TONIGHT. CAPPED CONDITIONS AT LOW-END MVFR FOR
NOW...HOWEVER IFR CONDITIONS ARE A POSSIBILITY.
EXTENDED AVIATION OUTLOOK...LOW TO MODERATE RISK OF OCCASIONAL
FLIGHT RESTRICTIONS WITH A COLD FRONT AND ASSOCIATED SHOWERS
TUESDAY AFTERNOON/EVENING.
&&
.MARINE...
TODAY...RECENTLY EXPANDED THE MARINE DENSE FOG ADVISORY TO INCLUDE
THE REMAINING SOUTH CAROLINA NEARSHORE ZONES AND EXTENDED THE
EXPIRATION TIME TO 10 AM. ITS UNCLEAR EXACTLY FAR OFFSHORE THE
MOST DENSE FOG RESIDES...BUT THERE IS ENOUGH EVIDENCE IN SATELLITE
DATA AND COASTAL WEBCAMS TO JUSTIFY KEEPING THE ADVISORY IN PLACE.
THE FOG WILL LIKELY LINGER FOR MUCH OF THE DAY AND POTENTIALLY
BECOME INTERMINGLED WITH SEA FOG THIS AFTERNOON AS INCREASING
DEWPOINTS ADVECT OVER THE COOLER SHELF WATERS. OTHERWISE...
NORTHEAST WINDS WILL GRADUALLY TURN SOUTHERLY LATER THIS MORNING
AND INCREASE TO 10-15 KT AS A WARM FRONT MOVES NORTH. SEAS WILL BE
2-4 FT.
TONIGHT...SOUTH WINDS 10-15 KT WILL BECOME SOUTHWEST AND INCREASE
TO 15-20 KT AS A COLD FRONT APPROACHES FROM THE WEST. THERE WILL
LIKELY BE A CONTINUED RISK FOR AT LEAST PATCHY SEA FOG...BUT THE
HIGHER WINDS SHOULD KEEP VISIBILITIES ABOVE 1 NM. SEAS WILL BUILD
TO 3-5 FT OFFSHORE WATERS AND CHARLESTON COUNTY NEARSHORE WATERS
TO 2-4 FT ELSEWHERE.
TUESDAY THROUGH FRIDAY...A COLD FRONT WILL MOVE THROUGH THE
FORECAST AREA ON TUESDAY...WITH MODERATE SOUTHERLY FLOW VEERING TO
THE NORTH OVERNIGHT. MARGINAL SMALL CRAFT ADVISORY CONDITIONS ARE
POSSIBLE WITHIN COLD ADVECTION FOLLOWING THE FRONTAL PASSAGE
TUESDAY NIGHT INTO EARLY WEDNESDAY. A BETTER CHANCE FOR ADVISORY
CONDITIONS WILL THEN OCCUR THURSDAY...AS A STRONGER HIGH PRESSURE
CENTER BUILDS INTO THE REGION AND TIGHTENS THE GRADIENT OVER THE
WATERS.
&&
.CHS WATCHES/WARNINGS/ADVISORIES...
GA...DENSE FOG ADVISORY UNTIL 10 AM EST THIS MORNING FOR GAZ087-088-
099>101-114>119-137>141.
SC...DENSE FOG ADVISORY UNTIL 10 AM EST THIS MORNING FOR SCZ040-
042>045-047>052.
MARINE...DENSE FOG ADVISORY UNTIL 10 AM EST THIS MORNING FOR AMZ330-350-
352-354.
&&
$$
ST/WMS
AREA FORECAST DISCUSSION...UPDATED
NWS CHICAGO/ROMEOVILLE IL
920 PM CST TUE DEC 10 2013
.DISCUSSION...
920 PM CST
THE CURRENT WINTER WEATHER ADVISORY FOR OVERNIGHT AND WEDNESDAY
MORNING CONTINUES AS IS WITH NO MAJOR CHANGES TO GOING FORECAST
SNOWFALL TIMING OR TOTAL AMOUNTS. HAVE ADDED PATCHY BLOWING SNOW
IN FOR THE MORNING IN THE FAR WEST AND SPREAD IT EASTWARD DURING
THE AFTERNOON AS THE COLD...OR SHOULD WE SAY COLDER...AIR SURGES
BACK IN.
THE POSITIVES TOWARD SNOWFALL WITH THIS SYSTEM REMAIN IN
OBSERVATIONAL AND SHORT TERM GUIDANCE...WITH HIGHER SNOW-TO-
LIQUID RATIOS AND TEMPORARY MODEST RATES...WHILE THE SUBTLE
CAVEATS OF A SOMEWHAT WEAK WAVE AND LOW COLUMN MOISTURE ARE LIKELY
TO BE OFFSET BY THESE ENOUGH TO PRODUCE 2-3.5" SNOWFALL AMOUNTS
AND LIKELY SCATTERED HIGHER AMOUNTS WITHIN THE ADVISORY AREA.
RADAR ECHOES ARE ON THE UPWARD TREND ACROSS CENTRAL IA WITHIN THE
WARM AIR ADVECTION WING OF THE SHORT WAVE SEEN ON WATER VAPOR
PROGRESSING EAST SOUTHEAST. THIS WAVE WILL TURN MORE EAST ALONG A
WELL-DEFINED 850-600MB BAROCLINIC ZONE SEEN ON THIS EVES UPPER
AIR DATA. HAVE ALREADY NOTED 3/4SM VISIBILITY IN IA...LIKELY
ASSOCIATED WITH ONE HALF TO ONE INCH PER HOUR TYPE RATES. WITH
CLIPPER SYSTEMS IT SEEMS THAT THE LOWEST VISIBILITY CAN OFTEN BE
EXTRAPOLATED OUT ALONG THE PATH GIVEN THE WAVE MAINTAINS ITS
INTENSITY. THE RAP CONTINUES TO SHOW A FAIRLY QUICK PROGRESSION
OF THE LEADING EDGE OF SNOW OVER MUCH OF THE FORECAST AREA BETWEEN
12AM-3AM...SO DID NOT GET FANCY WITH TRYING TO ADJUST THE ADVISORY
START TIME. TEMPORARY WEST-TO-EAST BANDED SNOW OVERNIGHT WOULD
SEEM PROBABLE IN NORTH CENTRAL IL...MAYBE INTO THE CHICAGO
METRO...ALONG THE BAROCLINIC ZONE AND FAIRLY WELL-DEFINED
MOISTURE CONVERGENCE. CONVECTIVE ALLOWING/HIGH RES GUIDANCE
INDICATES HIGHER REFLECTIVITY AS WELL IN THE 3-8 AM PERIOD. SNOW
LOOKS TO LINGER OVER CHICAGO THROUGH THE END OF THE ADVISORY TIME.
FORECAST SOUNDINGS CONTINUE TO INDICATE A VERY DEEP DENDRITIC
GROWTH AREA WITH NOT OVERLY HIGH WINDS BELOW THE CLOUD BASE FOR
FRAGMENTING. EVEN THE 00Z DVN SOUNDING HAD THE WET BULB
TEMPERATURE BASICALLY WITHIN THE DENDRITIC GROWTH AREA ALL THE WAY
TO ~10000 FT! THIS SHOULD ALLOW FOR GOOD EFFICIENCY (20:1) OF
MEAGER PWAT VALUES UNDER 0.2 INCH AND MIXING RATIOS IN THE CLOUD
LAYER OF 1-1.5 G/KG. SO WE CONTINUE A LITTLE HIGHER THAT MOST
GUIDANCE FOR SNOWFALL AMOUNTS.
THE MOST PROBABLE TIMING FOR HEAVIEST SNOWFALL RATES IN ROCKFORD
IS 2-6 AM AND CHICAGO IS 4-8 AM. TEMPERATURES SHOULD CONTINUE TO
INCH UP PRIOR TO THE SNOWFALL...AND THEN HOLD STEADY IN THE MID-
UPPER TEENS DURING THE SNOW.
MTF
&&
.PREV DISCUSSION...
250 PM...FORECAST CONCERNS INCLUDE ACCUMULATING SNOW TONIGHT INTO
WEDNESDAY MORNING...VERY COLD TEMPERATURES/WIND CHILLS WEDNESDAY
NIGHT AND ANOTHER POSSIBLE ACCUMULATING SNOW EVENT LATE FRIDAY
NIGHT INTO SATURDAY.
TEMPERATURES HAVE REBOUNDED QUITE A BIT FROM THIS MORNING/S SUB
ZERO READINGS WITH MANY AREAS IN THE LOWER/MID 20S. AS GUSTY WINDS
DIMINISH LATE THIS AFTERNOON INTO THIS EVENING...EXPECT TEMPS TO
STEADILY DROP INTO THE LOWER/MID TEENS AND THEN BECOME STEADY BY
LATE EVENING AND BEGIN RISING OVERNIGHT...POSSIBLY INTO THE LOWER
20S BY DAYBREAK.
A WEAK CLIPPER SYSTEM WILL MOVE ACROSS IOWA THIS EVENING AND THEN
ACROSS NORTHERN IL OVERNIGHT AND INTO NORTHWEST INDIANA WEDNESDAY
MORNING. FAIRLY GOOD AGREEMENT AMONG THE MODELS WITH A BAND OF
SNOW SPREADING INTO THE WESTERN CWA AROUND/SHORTLY AFTER MIDNIGHT
AND THEN ACROSS THE REST OF THE AREA DURING THE EARLY MORNING
HOURS...BEFORE SUNRISE. WHILE QPF AMOUNTS MAY ONLY RANGE IN THE
0.15 INCH RANGE...THE AIRMASS IS QUITE COLD AND EXPECT SNOW/WATER
RATIOS IN THE 18:1 TO 20:1 RANGE. THUS THE SNOW SHOULD BE QUITE
DRY AND FLUFFY. HAVE BUMPED QPF AMOUNTS AND SNOWFALL AMOUNTS UP
SLIGHTLY...GENERALLY IN THE 2.5 TO 3 INCH RANGE ALONG AND NORTH OF
INTERSTATE 80. AMOUNTS WILL QUICKLY TAPER OFF INTO THE SOUTHERN
THIRD OF THE CWA. THIS LOW BEGINS TO FILL SOME BY WEDNESDAY
MORNING AND AMOUNTS MAY BE HIGHER WESTERN AREAS THEN EASTERN
AREAS. THE ONE CONCERNING FACTOR IS THE GROWTH ZONE OF -10C TO
-14C WHICH BASED OF THE FORECAST SOUNDINGS COULD BE 150MB TO EVEN
200MB DEEP. THIS COULD ALLOW FOR SOME EFFICIENT SNOW DEVELOPMENT
ALONG WITH LARGE FLAKES...WHICH WOULD ALLOW FOR EVEN HIGHER
SNOWFALL AMOUNTS. THIS COULD ALSO LEAD TO SNOWFALL RATES
APPROACHING AN INCH AN HOUR FOR AT LEAST A SHORT TIME. WITH ALL
THIS IN MIND...WILL BE EXTENDING THE SNOW ADVISORY NORTH TO
INCLUDE THE FOUR NORTHERN COUNTIES AND MENTIONING STORM TOTAL
SNOWFALL AMOUNTS OF 2 TO 4 INCHES...WITH SOME UNCERTAINTY
REGARDING HOW WIDESPREAD THE 3 TO 4 INCH AMOUNTS MAY MATERIALIZE.
THE SNOW WILL TAPER OFF QUICKLY FROM WEST TO EAST AFTER SUNRISE
WITH NORTHWEST WINDS INCREASING AS THE SNOW ENDS AND THEN
REMAINING GUSTY INTO THE AFTERNOON. WIND GUSTS INTO THE 20-25 MPH
RANGE LOOK REASONABLE WHICH MAY CAUSE SOME BLOWING AND DRIFTING
SNOW BUT WILL MAINTAIN CURRENT ADVISORY EXPIRATION TIME OF 16Z
WEDNESDAY FOR NOW.
HIGH TEMPS WEDNESDAY WILL BE REACHED IN THE MORNING WITH STEADILY
FALLING TEMPS THROUGH THE AFTERNOON INTO WEDNESDAY NIGHT...WHICH
IS SHAPING UP TO BE VERY SIMILAR TO THIS MORNING. TEMPERATURES
WILL DIVE IN THE EVENING AND THEN BEGIN TO STEADY OVERNIGHT AND
POSSIBLY BEGIN TO RISE BY THURSDAY MORNING AS CLOUD COVER AND WEAK
WARM ADVECTION MOVE ACROSS THE REGION. BUT WITH A FRESH SNOW COVER
AND CLEARING SKIES...TEMPS SHOULD FALL BELOW ZERO JUST ABOUT
EVERYWHERE WITH THE USUAL COLD SPOTS PERHAPS INTO THE -10 RANGE.
THIS COMBINED WITH WESTERLY WINDS TURNING SOUTHWESTERLY...BUT IN
THE 10 MPH RANGE WILL PRODUCE WIND CHILLS FROM -15 TO -25 WITH
SOME LOCALLY LOWER VALUES. IF THESE TRENDS CONTINUE A WIND CHILL
ADVISORY MAY BE NEEDED DURING THIS TIME PERIOD.
TEMPS MODERATE SLIGHTLY THURSDAY INTO FRIDAY...THOUGH STILL BELOW
NORMAL. A COLD FRONT WILL SAG SOUTH ACROSS THE LAKES REGION
THURSDAY NIGHT AND FRIDAY...REACHING NORTHERN IL FRIDAY AFTERNOON.
MEANWHILE...LOW PRESSURE OVER THE SOUTHERN PLAINS LIFTS NORTHEAST
ACROSS THE OHIO VALLEY SATURDAY AND TO THE EASTERN LAKES BY SUNDAY
MORNING. A PROLONGED PERIOD OF LIGHT TO MODERATE SNOW WILL LIKELY
BEGIN FRIDAY NIGHT AND CONTINUE THROUGH MUCH OF SATURDAY WITH SOME
DIFFERENCES REGARDING THE CORRIDOR OF HEAVIEST QPF. BUT WITH
AMOUNTS IN THE 0.3 TO 0.5 RANGE...SEVERAL INCHES OF SNOW WILL BE
POSSIBLE. BUT WITH WARMER TEMPERATURES...PERHAPS NEAR FREEZING ON
SATURDAY...SNOW RATIOS SHOULD BE CLOSER TO 10:1 WITH A HEAVIER/WET
SNOW MOST LIKELY.
ANOTHER COLD DUMP SATURDAY NIGHT INTO SUNDAY. AND WHILE THE
STRENGTH OF COLD AIR IS STILL A BIT UNCERTAIN HAVE LOWERED TEMPS
SATURDAY NIGHT AND SUNDAY AND IF THIS MORNING AND WEDNESDAY NIGHT
ARE GOOD INDICATORS...TEMPS COULD BE SIGNIFICANTLY COLDER THAN
CURRENTLY ADVERTISED. CMS
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 03Z...
* SNOW ARRIVES OVERNIGHT AND PERSISTS THROUGH MID MORNING. LIFR
VSBY LIKELY WITH THE HEAVIER SNOW.
* MVFR CIGS AT OR LESS THAN 1500 FT ARE EXPECTED WITH THE SNOW.
* NORTHWEST WINDS GUSTING 20 TO 25 KT TOMORROW.
JEE
//DISCUSSION...UPDATED 00Z...
HIGH PRESSURE IS TO OUR SOUTH WITH THE NEXT CLIPPER SYSTEM
CURRENTLY OVER NORTHERN NEBRASKA. WINDS HAVE GENERALLY RELAXED
WITH SUSTAINED SPEEDS OF 10-15 KT...AND THEY WILL DIMINISH EVEN
FURTHER TO LESS THAN 10 KT AFTER MIDNIGHT. A HIGH LEVEL CLOUD DECK
IS ADVANCING FROM THE WEST AND WILL MOVE OVER THE TERMINALS
SHORTLY.
THE CLIPPER SYSTEM ARRIVES AFTER MIDNIGHT AS WELL...AND THE
PREVIOUS TIMING IN THE TAFS STILL LOOKS REASONABLE SO DID NOT MAKE
ANY ADJUSTMENTS TO IT. SNOW WILL LIKELY INTENSIFY QUICKLY WITH
VISIBILITIES LOWERING TO IFR OR LOWER BY 09Z. CIGS WILL ALSO FALL
TO MVFR AS THE SYSTEM MOVES IN. A DRY FLUFFY SNOW IS
EXPECTED...AND GIVEN THE COLD CONDITIONS...SNOW SHOULD BEGIN
ACCUMULATING IMMEDIATELY. 2 TO 4 INCHES ARE EXPECTED WHEN ALL IS
SAID AND DONE.
THE SYSTEM SHIFTS EAST WITH SNOW DIMINISHING BY MID MORNING. CIGS
SLOWLY IMPROVE TO ABOVE 1500 FT BY MID MORNING AS
WELL...EVENTUALLY THINNING AND BECOMING VFR BY MID AFTN.
JEE
//ORD AND MDW CONFIDENCE...UPDATED 03Z...
* MEDIUM-HIGH CONFIDENCE IN TIMING OF SNOW AND RELATED CIGS.
* MEDIUM-HIGH CONFIDENCE IN TIMING OF MOST INTENSE SNOW. HIGH
CONFIDENCE IN LIFR OR LOWER VSBY DURING THIS PERIOD.
* HIGH CONFIDENCE IN ALL OTHER FORECAST PARAMETERS.
JEE
//OUTLOOK FOR ORD/MDW FOR 12Z THURSDAY-12Z TUESDAY...UPDATED 00Z...
THURSDAY...VFR.
FRIDAY...SNOW ESPECIALLY OVERNIGHT.
SATURDAY...SNOW DURING THE DAY...TAPERING OFF AT NIGHT. MVFR OR
LOWER PSBL.
SUNDAY...CHANCE OF SNOW EARLY WITH CONDITIONS IMPROVING TO VFR
THROUGH THE DAY.
MONDAY...CHANCE OF SNOW...VFR.
JEE
&&
.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 MICHIGAN 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...ILZ003-ILZ004-ILZ005-ILZ006-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...LMZ261-LMZ362-LMZ364-LMZ366-LMZ563-LMZ565 UNTIL 3
AM WEDNESDAY.
&&
$$
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FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
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WWW.TWITTER.COM/NWSCHICAGO
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AREA FORECAST DISCUSSION
NWS INDIANAPOLIS IN
300 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 /TONIGHT/...
ISSUED AT 148 PM EST MON DEC 9 2013
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 092100Z TAF ISSUANCE/...
ISSUED AT 1220 PM EST MON DEC 9 2013
STRATUS HAS BROKEN UP A BIT FASTER THAN PREVIOUSLY THOUGHT THIS
AFTERNOON. UPDATED TAFS TO REFLECT THAT. NO OTHER CHANGES.
18Z DISCUSSION FOLLOWS.
MVFR CEILINGS WILL CONTINUE THIS AFTERNOON. MVFR/IFR CONDITIONS
POSSIBLE TONIGHT AT ALL SITES EXCEPT KLAF IN LIGHT SNOW.
STUBBORN STRATUS DECK HOLDING WITH MOISTURE TRAPPED UNDERNEATH THE
INVERSION..BUT BREAKS IN THE LOWER DECK ARE TRYING TO EXPAND EAST
INTO THE REGION. EXPECT MORE SUBSTANTIAL DEPARTURE OF THE STRATUS TO
TAKE MUCH OF THE AFTERNOON TO LIFT AND MIX OUT WITH COLD ADVECTION
ONGOING. BOTH THE NAM AND RAP INDICATED DRYING TAKING PLACE WITHIN
THE BOUNDARY LAYER BY LATE AFTERNOON AND EARLY EVENING...WITH THE
PREDOMINANT CEILING SHIFTING UP TO AROUND 10KFT. SPORADIC GUSTS TO
AROUND 20KTS POSSIBLE THROUGH THE AFTERNOON WITH W/NW WINDS.
FAST MOVING UPPER LEVEL WAVE WILL TRACK THROUGH THE OHIO VALLEY
OVERNIGHT...SPREADING LIGHT SNOW ACROSS THE SOUTHERN HALF OF
CENTRAL INDIANA. SUBTLE PLACEMENT DIFFERENCE PRESENT AMONGST ALL
OF THE SHORT RANGE MODEL GUIDANCE...BUT CONFIDENCE IS HIGH IN
LIGHT SNOW IMPACTING KBMG/KHUF/KIND BEGINNING 04-05Z AND
PERSISTING THROUGH AROUND DAYBREAK. GREATEST IMPACT ANTICIPATED AT
KBMG WHERE IFR CONDITIONS ARE POSSIBLE WITHIN HEAVIER SNOWFALL.
SNOWFALL RATES WILL BE LIGHTER ALONG THE I-70 CORRIDOR...WITH
PRIMARILY MVFR CONDITIONS IMPACTING BOTH KHUF AND KIND. LIGHT
NORTHWEST WINDS EXPECTED OVERNIGHT.
LIGHT SNOW WILL MOVE OFF TO THE EAST QUICKLY TUESDAY MORNING WITH
STEADILY IMPROVING CONDITIONS AT ALL TERMINALS. CEILINGS SHOULD
MIX OUT TO A SCATTERED VFR CU/STRATOCU DECK BY EARLY AFTERNOON.
MAIN IMPACT TO TERMINALS ON TUESDAY WILL BE WINDS AS TIGHTENING
SURFACE PRESSURE GRADIENT AND INCREASING FLOW THROUGH THE BOUNDARY
LAYER WILL SUPPORT WINDY CONDITIONS BY LATE MORNING. SOUTHWEST
SUSTAINEDS WILL INCREASE TO 15-20KTS WITH GUSTS AT 25-30KTS FROM
15-16Z CONTINUING INTO THE AFTERNOON.
&&
.IND WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
SYNOPSIS...TUCEK
NEAR TERM...TUCEK
SHORT TERM...TUCEK
LONG TERM....RYAN
AVIATION...RYAN
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
255 PM EST MON DEC 9 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 /TONIGHT/...
ISSUED AT 148 PM EST MON DEC 9 2013
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
MEASUREABLE 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 091800Z TAF ISSUANCE/...
ISSUED AT 1220 PM EST MON DEC 9 2013
MVFR CEILINGS WILL CONTINUE THIS AFTERNOON. MVFR/IFR CONDITIONS
POSSIBLE TONIGHT AT ALL SITES EXCEPT KLAF IN LIGHT SNOW.
STUBBORN STRATUS DECK HOLDING WITH MOISTURE TRAPPED UNDERNEATH THE
INVERSION..BUT BREAKS IN THE LOWER DECK ARE TRYING TO EXPAND EAST
INTO THE REGION. EXPECT MORE SUBSTANTIAL DEPARTURE OF THE STRATUS TO
TAKE MUCH OF THE AFTERNOON TO LIFT AND MIX OUT WITH COLD ADVECTION
ONGOING. BOTH THE NAM AND RAP INDICATED DRYING TAKING PLACE WITHIN
THE BOUNDARY LAYER BY LATE AFTERNOON AND EARLY EVENING...WITH THE
PREDOMINANT CEILING SHIFTING UP TO AROUND 10KFT. SPORADIC GUSTS TO
AROUND 20KTS POSSIBLE THROUGH THE AFTERNOON WITH W/NW WINDS.
FAST MOVING UPPER LEVEL WAVE WILL TRACK THROUGH THE OHIO VALLEY
OVERNIGHT...SPREADING LIGHT SNOW ACROSS THE SOUTHERN HALF OF
CENTRAL INDIANA. SUBTLE PLACEMENT DIFFERENCE PRESENT AMONGST ALL
OF THE SHORT RANGE MODEL GUIDANCE...BUT CONFIDENCE IS HIGH IN
LIGHT SNOW IMPACTING KBMG/KHUF/KIND BEGINNING 04-05Z AND
PERSISTING THROUGH AROUND DAYBREAK. GREATEST IMPACT ANTICIPATED AT
KBMG WHERE IFR CONDITIONS ARE POSSIBLE WITHIN HEAVIER SNOWFALL.
SNOWFALL RATES WILL BE LIGHTER ALONG THE I-70 CORRIDOR...WITH
PRIMARILY MVFR CONDITIONS IMPACTING BOTH KHUF AND KIND. LIGHT
NORTHWEST WINDS EXPECTED OVERNIGHT.
LIGHT SNOW WILL MOVE OFF TO THE EAST QUICKLY TUESDAY MORNING WITH
STEADILY IMPROVING CONDITIONS AT ALL TERMINALS. CEILINGS SHOULD
MIX OUT TO A SCATTERED VFR CU/STRATOCU DECK BY EARLY AFTERNOON.
MAIN IMPACT TO TERMINALS ON TUESDAY WILL BE WINDS AS TIGHTENING
SURFACE PRESSURE GRADIENT AND INCREASING FLOW THROUGH THE BOUNDARY
LAYER WILL SUPPORT WINDY CONDITIONS BY LATE MORNING. SOUTHWEST
SUSTAINEDS WILL INCREASE TO 15-20KTS WITH GUSTS AT 25-30KTS FROM
15-16Z CONTINUING INTO THE AFTERNOON.
&&
.IND WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
SYNOPSIS...TUCEK
NEAR TERM...TUCEK
SHORT TERM...TUCEK
LONG TERM....RYAN
AVIATION...RYAN
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
223 PM EST MON DEC 9 2013
.UPDATE...
THE SYNOPSIS...NEAR TERM AND SHORT TERM SECTIONS HAVE 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 /TONIGHT/...
ISSUED AT 148 PM EST MON DEC 9 2013
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
MEASUREABLE 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 THROUGH SUNDAY/...
ISSUED AT 333 AM EST MON DEC 9 2013
MODEL ENSEMBLES INDICATE HIGH PRESSURE WILL BE ACROSS THE OHIO
VALLEY THURSDAY WHICH WILL MOVE ON TO THE EAST FRIDAY. A RETURN
FLOW ON THE BACK SIDE OF THE HIGH WILL BRING A SLIGHT MODERATION OF
TEMPERATURES BY FRIDAY. OVERALL ONLY MADE A FEW TWEAKS TO ALL BLEND
TEMPERATURES THURSDAY AND FRIDAY.
MODELS INDICATE A COUPLE OF UPPER DISTURBANCES IN THE SOUTHERN
STREAM WILL AFFECT OUR WEATHER FRIDAY NIGHT AND SATURDAY WITH LOW
PRESSURE DEVELOPING OVER TENNESSEE AND TRACKING TOWARDS THE CENTRAL
APPALACHIANS BY SATURDAY EVENING. MODELS HAVE ALSO TRENDED A LITTLE
WETTER FOR FRIDAY NIGHT AND SATURDAY. 1000-700 MB THICKNESS FAVOR
SNOW OVER THE NORTHERN HALF TO TWO THIRDS OF OUR REGION AND A WINTRY
MIX TO THE SOUTH. THIS SHOULD MOVE OUT SATURDAY NIGHT...BUT SOME
MODELS INDICATE TRACE PRECIP AMOUNTS MAY LINGER INTO SATURDAY
NIGHT...SO WILL ADD 20 PERCENT POPS MOST AREAS. THE GFS REMAINS DRY
ON SUNDAY WHILE THE EURO INDICATES POSSIBLE SNOW SHOWERS SOME AREAS
WITH A STRONGER UPPER LOW MOVING INTO THE GREAT LAKES. WITH POOR
AGREEMENT BETWEEN MODELS WILL KEEP EVERYTHING DRY FOR NOW ON SUNDAY.
IN REGARDS TO TEMPERATURES OVER THE WEEKEND...WENT A LITTLE ABOVE
ALL BLEND TEMPERATURES FRIDAY AND SATURDAY NIGHT DUE TO LOTS OF
CLOUDS AND A LITTLE COLDER SUNDAY TO PARTIALLY MATCH THE COLDER
TREND OF THE NEW EURO. IN MOST CASES THESE WERE ONLY MINOR TWEAK TO
ALL BLEND TEMPERATURES.
&&
.AVIATION /DISCUSSION FOR 091800Z TAF ISSUANCE/...
ISSUED AT 1220 PM EST MON DEC 9 2013
MVFR CEILINGS WILL CONTINUE THIS AFTERNOON. MVFR/IFR CONDITIONS
POSSIBLE TONIGHT AT ALL SITES EXCEPT KLAF IN LIGHT SNOW.
STUBBORN STRATUS DECK HOLDING WITH MOISTURE TRAPPED UNDERNEATH THE
INVERSION..BUT BREAKS IN THE LOWER DECK ARE TRYING TO EXPAND EAST
INTO THE REGION. EXPECT MORE SUBSTANTIAL DEPARTURE OF THE STRATUS TO
TAKE MUCH OF THE AFTERNOON TO LIFT AND MIX OUT WITH COLD ADVECTION
ONGOING. BOTH THE NAM AND RAP INDICATED DRYING TAKING PLACE WITHIN
THE BOUNDARY LAYER BY LATE AFTERNOON AND EARLY EVENING...WITH THE
PREDOMINANT CEILING SHIFTING UP TO AROUND 10KFT. SPORADIC GUSTS TO
AROUND 20KTS POSSIBLE THROUGH THE AFTERNOON WITH W/NW WINDS.
FAST MOVING UPPER LEVEL WAVE WILL TRACK THROUGH THE OHIO VALLEY
OVERNIGHT...SPREADING LIGHT SNOW ACROSS THE SOUTHERN HALF OF
CENTRAL INDIANA. SUBTLE PLACEMENT DIFFERENCE PRESENT AMONGST ALL
OF THE SHORT RANGE MODEL GUIDANCE...BUT CONFIDENCE IS HIGH IN
LIGHT SNOW IMPACTING KBMG/KHUF/KIND BEGINNING 04-05Z AND
PERSISTING THROUGH AROUND DAYBREAK. GREATEST IMPACT ANTICIPATED AT
KBMG WHERE IFR CONDITIONS ARE POSSIBLE WITHIN HEAVIER SNOWFALL.
SNOWFALL RATES WILL BE LIGHTER ALONG THE I-70 CORRIDOR...WITH
PRIMARILY MVFR CONDITIONS IMPACTING BOTH KHUF AND KIND. LIGHT
NORTHWEST WINDS EXPECTED OVERNIGHT.
LIGHT SNOW WILL MOVE OFF TO THE EAST QUICKLY TUESDAY MORNING WITH
STEADILY IMPROVING CONDITIONS AT ALL TERMINALS. CEILINGS SHOULD
MIX OUT TO A SCATTERED VFR CU/STRATOCU DECK BY EARLY AFTERNOON.
MAIN IMPACT TO TERMINALS ON TUESDAY WILL BE WINDS AS TIGHTENING
SURFACE PRESSURE GRADIENT AND INCREASING FLOW THROUGH THE BOUNDARY
LAYER WILL SUPPORT WINDY CONDITIONS BY LATE MORNING. SOUTHWEST
SUSTAINEDS WILL INCREASE TO 15-20KTS WITH GUSTS AT 25-30KTS FROM
15-16Z CONTINUING INTO THE AFTERNOON.
&&
.IND WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...TUCEK
NEAR TERM...TUCEK
SHORT TERM...TUCEK
LONG TERM....JH
AVIATION...RYAN
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
1226 PM EST MON DEC 9 2013
.UPDATE...
THE NEAR TERM SECTION HAS BEEN UPDATED BELOW.
&&
.SYNOPSIS...
ISSUED AT 337 AM EST MON DEC 9 2013
HIGH PRESSURE WILL BRIEFLY MOVE INTO THE AREA TODAY BUT ANOTHER
UPPER DISTURBANCE WILL PROVIDE A CHANCE FOR SNOW FOR PARTS OF
CENTRAL INDIANA TONIGHT AND EARLY TUESDAY. AN AREA OF LOW PRESSURE
WILL THEN BRING A SMALL CHANCE FOR SNOW TO OTHER PARTS OF THE AREA
WEDNESDAY. COLDER AIR WILL THEN FLOW IN FOR THURSDAY.
TEMPERATURES WILL MODERATE BY THE WEEKEND BUT YET ANOTHER SYSTEM
WILL BRING CHANCES FOR PRECIPITATION FRIDAY NIGHT INTO SATURDAY.
&&
.NEAR TERM /THIS AFTERNOON/...
ISSUED AT 1221 PM EST MON DEC 9 2013
LOOKS LIKE BANDED LOW LEVEL CLOUDS THAT HAVE BEEN PRODUCING LIGHT
SNOW SHOWERS HAS DIMINISHED OVER CENTRAL INDIANA AND CURRENTLY
CONFINED TO NORTHERN INDIANA NE IL SO WILL END MENTION OF FLURRIES HERE.
SOME BREAKS IN CLOUDS AND BRIGHTENING OF SKY EXPECTED BUT OVERALL
MOSTLY CLOUDY WORDING STILL WORKS AND DESPITE BRIGHTER
SKIES...STRENGTH OF COLD ACROSS ILLINOIS SUGGESTS NO REAL WARMING
TO OCCUR. HAVE BUMPED WIND SPEEDS UP A TAD TO MATCH CURRENT OBS.
&&
.SHORT TERM /TONIGHT THROUGH WEDNESDAY NIGHT/...
ISSUED AT 337 AM EST MON DEC 9 2013
FOCUS IS ON CHANCES FOR PRECIPITATION THROUGH THE PERIOD. MODELS ARE
IN DECENT AGREEMENT WITH THE BIG PICTURE SO USED A BLEND FOR MOST
PERIODS.
TONIGHT ISENTROPIC LIFT INCREASES ONCE AGAIN IN ADVANCE OF AN UPPER
WAVE. BEST FORCING AND MOISTURE LOOK TO BE CONFINED TO THE SOUTHERN
2/3 OF THE FORECAST AREA. THERE LOOKS TO BE SOME FRONTOGENETICAL
FORCING ACROSS MAINLY THE SOUTHERN HALF OF THE AREA AS WELL.
NAM IS FARTHEST NORTH WITH PRECIPITATION WITH OTHERS A BIT FARTHER
SOUTH. THIS LOOKS TO BE ANOTHER CASE WITH A VERY SHARP CUTOFF OF
POTENTIAL ACCUMULATING SNOW AND NO SNOW AT ALL. THUS CONFIDENCE IS
ONLY LOW TO MEDIUM IN NORTHERN PLACEMENT OF POPS...ESPECIALLY NORTH.
WILL GO DRY IN THE FAR NORTHWEST TONIGHT WITH A QUICK TRANSITION TO
HIGH CHANCE CATEGORY POPS SOUTH. IF NAM IS RIGHT WILL HAVE TO BUMP
TO LIKELY POPS ACROSS THE SOUTH WITH LATER FORECASTS. WILL CONTINUE
TO WATCH CLOSELY. POTENTIAL EXISTS FOR A QUICK INCH OR SO IN SOME
AREAS ACROSS THE SOUTH.
FORCING QUICKLY ENDS LATE TONIGHT INTO EARLY TUESDAY SO ONLY WENT
SLIGHT CHANCE POPS EARLY TUESDAY ACROSS THE FAR SOUTHEAST. OTHERWISE
CLOUDS WILL DECREASE TUESDAY AS SYSTEM EXITS. HOWEVER CLOUDS WILL
INCREASE ACROSS THE NORTH TUESDAY NIGHT AS THE NEXT SYSTEM
APPROACHES.
AN AREA OF LOW PRESSURE WILL MOVE ACROSS THE LOWER GREAT LAKES
WEDNESDAY. BEST FORCING AND MOISTURE REMAIN NORTH OF THE FORECAST
AREA...BUT LOOKS LIKE JUST ENOUGH MIGHT SNEAK INTO THE FAR NORTHERN
FORECAST AREA TO GO SLIGHT CHANCE POPS. DRY CONDITIONS WILL PREVAIL
WEDNESDAY NIGHT AS SYSTEM EXITS.
LOOKING AT TEMPERATURES...MAV LOOKS TOO COLD TONIGHT GIVEN EXPECTED
CLOUD COVER WITH NEXT SYSTEM. WENT CLOSER TO WARMER MET. ON TUESDAY
MAV LOOKS TOO WARM MANY AREAS GIVEN SOME COLD ADVECTION DURING PART
OF THE DAY. WENT CLOSER TO MET. AT OTHER TIMES USED A BLEND.
&&
.LONG TERM /THURSDAY THROUGH SUNDAY/...
ISSUED AT 333 AM EST MON DEC 9 2013
MODEL ENSEMBLES INDICATE HIGH PRESSURE WILL BE ACROSS THE OHIO
VALLEY THURSDAY WHICH WILL MOVE ON TO THE EAST FRIDAY. A RETURN
FLOW ON THE BACK SIDE OF THE HIGH WILL BRING A SLIGHT MODERATION OF
TEMPERATURES BY FRIDAY. OVERALL ONLY MADE A FEW TWEAKS TO ALL BLEND
TEMPERATURES THURSDAY AND FRIDAY.
MODELS INDICATE A COUPLE OF UPPER DISTURBANCES IN THE SOUTHERN
STREAM WILL AFFECT OUR WEATHER FRIDAY NIGHT AND SATURDAY WITH LOW
PRESSURE DEVELOPING OVER TENNESSEE AND TRACKING TOWARDS THE CENTRAL
APPALACHIANS BY SATURDAY EVENING. MODELS HAVE ALSO TRENDED A LITTLE
WETTER FOR FRIDAY NIGHT AND SATURDAY. 1000-700 MB THICKNESS FAVOR
SNOW OVER THE NORTHERN HALF TO TWO THIRDS OF OUR REGION AND A WINTRY
MIX TO THE SOUTH. THIS SHOULD MOVE OUT SATURDAY NIGHT...BUT SOME
MODELS INDICATE TRACE PRECIP AMOUNTS MAY LINGER INTO SATURDAY
NIGHT...SO WILL ADD 20 PERCENT POPS MOST AREAS. THE GFS REMAINS DRY
ON SUNDAY WHILE THE EURO INDICATES POSSIBLE SNOW SHOWERS SOME AREAS
WITH A STRONGER UPPER LOW MOVING INTO THE GREAT LAKES. WITH POOR
AGREEMENT BETWEEN MODELS WILL KEEP EVERYTHING DRY FOR NOW ON SUNDAY.
IN REGARDS TO TEMPERATURES OVER THE WEEKEND...WENT A LITTLE ABOVE
ALL BLEND TEMPERATURES FRIDAY AND SATURDAY NIGHT DUE TO LOTS OF
CLOUDS AND A LITTLE COLDER SUNDAY TO PARTIALLY MATCH THE COLDER
TREND OF THE NEW EURO. IN MOST CASES THESE WERE ONLY MINOR TWEAK TO
ALL BLEND TEMPERATURES.
&&
.AVIATION /DISCUSSION FOR 091800Z TAF ISSUANCE/...
ISSUED AT 1220 PM EST MON DEC 9 2013
MVFR CEILINGS WILL CONTINUE THIS AFTERNOON. MVFR/IFR CONDITIONS
POSSIBLE TONIGHT AT ALL SITES EXCEPT KLAF IN LIGHT SNOW.
STUBBORN STRATUS DECK HOLDING WITH MOISTURE TRAPPED UNDERNEATH THE
INVERSION..BUT BREAKS IN THE LOWER DECK ARE TRYING TO EXPAND EAST
INTO THE REGION. EXPECT MORE SUBSTANTIAL DEPARTURE OF THE STRATUS TO
TAKE MUCH OF THE AFTERNOON TO LIFT AND MIX OUT WITH COLD ADVECTION
ONGOING. BOTH THE NAM AND RAP INDICATED DRYING TAKING PLACE WITHIN
THE BOUNDARY LAYER BY LATE AFTERNOON AND EARLY EVENING...WITH THE
PREDOMINANT CEILING SHIFTING UP TO AROUND 10KFT. SPORADIC GUSTS TO
AROUND 20KTS POSSIBLE THROUGH THE AFTERNOON WITH W/NW WINDS.
FAST MOVING UPPER LEVEL WAVE WILL TRACK THROUGH THE OHIO VALLEY
OVERNIGHT...SPREADING LIGHT SNOW ACROSS THE SOUTHERN HALF OF
CENTRAL INDIANA. SUBTLE PLACEMENT DIFFERENCE PRESENT AMONGST ALL
OF THE SHORT RANGE MODEL GUIDANCE...BUT CONFIDENCE IS HIGH IN
LIGHT SNOW IMPACTING KBMG/KHUF/KIND BEGINNING 04-05Z AND
PERSISTING THROUGH AROUND DAYBREAK. GREATEST IMPACT ANTICIPATED AT
KBMG WHERE IFR CONDITIONS ARE POSSIBLE WITHIN HEAVIER SNOWFALL.
SNOWFALL RATES WILL BE LIGHTER ALONG THE I-70 CORRIDOR...WITH
PRIMARILY MVFR CONDITIONS IMPACTING BOTH KHUF AND KIND. LIGHT
NORTHWEST WINDS EXPECTED OVERNIGHT.
LIGHT SNOW WILL MOVE OFF TO THE EAST QUICKLY TUESDAY MORNING WITH
STEADILY IMPROVING CONDITIONS AT ALL TERMINALS. CEILINGS SHOULD
MIX OUT TO A SCATTERED VFR CU/STRATOCU DECK BY EARLY AFTERNOON.
MAIN IMPACT TO TERMINALS ON TUESDAY WILL BE WINDS AS TIGHTENING
SURFACE PRESSURE GRADIENT AND INCREASING FLOW THROUGH THE BOUNDARY
LAYER WILL SUPPORT WINDY CONDITIONS BY LATE MORNING. SOUTHWEST
SUSTAINEDS WILL INCREASE TO 15-20KTS WITH GUSTS AT 25-30KTS FROM
15-16Z CONTINUING INTO THE AFTERNOON.
&&
.IND WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...50
NEAR TERM...TUCEK
SHORT TERM...50
LONG TERM....JH
AVIATION...RYAN
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
1220 PM EST MON DEC 9 2013
.UPDATE...
THE AVIATION SECTION HAS BEEN UPDATED BELOW.
&&
.SYNOPSIS...
ISSUED AT 337 AM EST MON DEC 9 2013
HIGH PRESSURE WILL BRIEFLY MOVE INTO THE AREA TODAY BUT ANOTHER
UPPER DISTURBANCE WILL PROVIDE A CHANCE FOR SNOW FOR PARTS OF
CENTRAL INDIANA TONIGHT AND EARLY TUESDAY. AN AREA OF LOW PRESSURE
WILL THEN BRING A SMALL CHANCE FOR SNOW TO OTHER PARTS OF THE AREA
WEDNESDAY. COLDER AIR WILL THEN FLOW IN FOR THURSDAY.
TEMPERATURES WILL MODERATE BY THE WEEKEND BUT YET ANOTHER SYSTEM
WILL BRING CHANCES FOR PRECIPITATION FRIDAY NIGHT INTO SATURDAY.
&&
.NEAR TERM /TODAY/...
ISSUED AT 919 AM EST MON DEC 9 2013
INTRODUCING FLURRIES INTO FORECAST THROUGH MID AFTERNOON GIVEN
WEAK RADAR RETURNS COUPLED WITH SURFACE OBSERVED LIGHT SNOW
OCCURRING. DO NOT EXPECT ACCUMULATION THOUGH GIVEN NO VSBY DROP
ACCOMPANYING CURRENT SNOW AND FLAKES QUITE SMALL.
CLEARING ACROSS WC AND NW IL SHOULD WORK ITS WAY INTO WESTERN
COUNTIES BY LATE AFTERNOON AS HIGH PRESSURE BUILDS IN BUT RETURN
OF HIGH CLOUDS FROM SOUTHERN SYSTEMS APPROACH TO RETURN HIGHER
DECKS BY NIGHTFALL.
TEMPS TO HOLD FAIRLY STEADY THROUGH THE DAY GIVEN CLOUD DECK
HOLDING AND COLD ADVECTION BEGINNING TO TAKE PLACE.
&&
.SHORT TERM /TONIGHT THROUGH WEDNESDAY NIGHT/...
ISSUED AT 337 AM EST MON DEC 9 2013
FOCUS IS ON CHANCES FOR PRECIPITATION THROUGH THE PERIOD. MODELS ARE
IN DECENT AGREEMENT WITH THE BIG PICTURE SO USED A BLEND FOR MOST
PERIODS.
TONIGHT ISENTROPIC LIFT INCREASES ONCE AGAIN IN ADVANCE OF AN UPPER
WAVE. BEST FORCING AND MOISTURE LOOK TO BE CONFINED TO THE SOUTHERN
2/3 OF THE FORECAST AREA. THERE LOOKS TO BE SOME FRONTOGENETICAL
FORCING ACROSS MAINLY THE SOUTHERN HALF OF THE AREA AS WELL.
NAM IS FARTHEST NORTH WITH PRECIPITATION WITH OTHERS A BIT FARTHER
SOUTH. THIS LOOKS TO BE ANOTHER CASE WITH A VERY SHARP CUTOFF OF
POTENTIAL ACCUMULATING SNOW AND NO SNOW AT ALL. THUS CONFIDENCE IS
ONLY LOW TO MEDIUM IN NORTHERN PLACEMENT OF POPS...ESPECIALLY NORTH.
WILL GO DRY IN THE FAR NORTHWEST TONIGHT WITH A QUICK TRANSITION TO
HIGH CHANCE CATEGORY POPS SOUTH. IF NAM IS RIGHT WILL HAVE TO BUMP
TO LIKELY POPS ACROSS THE SOUTH WITH LATER FORECASTS. WILL CONTINUE
TO WATCH CLOSELY. POTENTIAL EXISTS FOR A QUICK INCH OR SO IN SOME
AREAS ACROSS THE SOUTH.
FORCING QUICKLY ENDS LATE TONIGHT INTO EARLY TUESDAY SO ONLY WENT
SLIGHT CHANCE POPS EARLY TUESDAY ACROSS THE FAR SOUTHEAST. OTHERWISE
CLOUDS WILL DECREASE TUESDAY AS SYSTEM EXITS. HOWEVER CLOUDS WILL
INCREASE ACROSS THE NORTH TUESDAY NIGHT AS THE NEXT SYSTEM
APPROACHES.
AN AREA OF LOW PRESSURE WILL MOVE ACROSS THE LOWER GREAT LAKES
WEDNESDAY. BEST FORCING AND MOISTURE REMAIN NORTH OF THE FORECAST
AREA...BUT LOOKS LIKE JUST ENOUGH MIGHT SNEAK INTO THE FAR NORTHERN
FORECAST AREA TO GO SLIGHT CHANCE POPS. DRY CONDITIONS WILL PREVAIL
WEDNESDAY NIGHT AS SYSTEM EXITS.
LOOKING AT TEMPERATURES...MAV LOOKS TOO COLD TONIGHT GIVEN EXPECTED
CLOUD COVER WITH NEXT SYSTEM. WENT CLOSER TO WARMER MET. ON TUESDAY
MAV LOOKS TOO WARM MANY AREAS GIVEN SOME COLD ADVECTION DURING PART
OF THE DAY. WENT CLOSER TO MET. AT OTHER TIMES USED A BLEND.
&&
.LONG TERM /THURSDAY THROUGH SUNDAY/...
ISSUED AT 333 AM EST MON DEC 9 2013
MODEL ENSEMBLES INDICATE HIGH PRESSURE WILL BE ACROSS THE OHIO
VALLEY THURSDAY WHICH WILL MOVE ON TO THE EAST FRIDAY. A RETURN
FLOW ON THE BACK SIDE OF THE HIGH WILL BRING A SLIGHT MODERATION OF
TEMPERATURES BY FRIDAY. OVERALL ONLY MADE A FEW TWEAKS TO ALL BLEND
TEMPERATURES THURSDAY AND FRIDAY.
MODELS INDICATE A COUPLE OF UPPER DISTURBANCES IN THE SOUTHERN
STREAM WILL AFFECT OUR WEATHER FRIDAY NIGHT AND SATURDAY WITH LOW
PRESSURE DEVELOPING OVER TENNESSEE AND TRACKING TOWARDS THE CENTRAL
APPALACHIANS BY SATURDAY EVENING. MODELS HAVE ALSO TRENDED A LITTLE
WETTER FOR FRIDAY NIGHT AND SATURDAY. 1000-700 MB THICKNESS FAVOR
SNOW OVER THE NORTHERN HALF TO TWO THIRDS OF OUR REGION AND A WINTRY
MIX TO THE SOUTH. THIS SHOULD MOVE OUT SATURDAY NIGHT...BUT SOME
MODELS INDICATE TRACE PRECIP AMOUNTS MAY LINGER INTO SATURDAY
NIGHT...SO WILL ADD 20 PERCENT POPS MOST AREAS. THE GFS REMAINS DRY
ON SUNDAY WHILE THE EURO INDICATES POSSIBLE SNOW SHOWERS SOME AREAS
WITH A STRONGER UPPER LOW MOVING INTO THE GREAT LAKES. WITH POOR
AGREEMENT BETWEEN MODELS WILL KEEP EVERYTHING DRY FOR NOW ON SUNDAY.
IN REGARDS TO TEMPERATURES OVER THE WEEKEND...WENT A LITTLE ABOVE
ALL BLEND TEMPERATURES FRIDAY AND SATURDAY NIGHT DUE TO LOTS OF
CLOUDS AND A LITTLE COLDER SUNDAY TO PARTIALLY MATCH THE COLDER
TREND OF THE NEW EURO. IN MOST CASES THESE WERE ONLY MINOR TWEAK TO
ALL BLEND TEMPERATURES.
&&
.AVIATION /DISCUSSION FOR 091800Z TAF ISSUANCE/...
ISSUED AT 1220 PM EST MON DEC 9 2013
MVFR CEILINGS WILL CONTINUE THIS AFTERNOON. MVFR/IFR CONDITIONS
POSSIBLE TONIGHT AT ALL SITES EXCEPT KLAF IN LIGHT SNOW.
STUBBORN STRATUS DECK HOLDING WITH MOISTURE TRAPPED UNDERNEATH THE
INVERSION..BUT BREAKS IN THE LOWER DECK ARE TRYING TO EXPAND EAST
INTO THE REGION. EXPECT MORE SUBSTANTIAL DEPARTURE OF THE STRATUS TO
TAKE MUCH OF THE AFTERNOON TO LIFT AND MIX OUT WITH COLD ADVECTION
ONGOING. BOTH THE NAM AND RAP INDICATED DRYING TAKING PLACE WITHIN
THE BOUNDARY LAYER BY LATE AFTERNOON AND EARLY EVENING...WITH THE
PREDOMINANT CEILING SHIFTING UP TO AROUND 10KFT. SPORADIC GUSTS TO
AROUND 20KTS POSSIBLE THROUGH THE AFTERNOON WITH W/NW WINDS.
FAST MOVING UPPER LEVEL WAVE WILL TRACK THROUGH THE OHIO VALLEY
OVERNIGHT...SPREADING LIGHT SNOW ACROSS THE SOUTHERN HALF OF
CENTRAL INDIANA. SUBTLE PLACEMENT DIFFERENCE PRESENT AMONGST ALL
OF THE SHORT RANGE MODEL GUIDANCE...BUT CONFIDENCE IS HIGH IN
LIGHT SNOW IMPACTING KBMG/KHUF/KIND BEGINNING 04-05Z AND
PERSISTING THROUGH AROUND DAYBREAK. GREATEST IMPACT ANTICIPATED AT
KBMG WHERE IFR CONDITIONS ARE POSSIBLE WITHIN HEAVIER SNOWFALL.
SNOWFALL RATES WILL BE LIGHTER ALONG THE I-70 CORRIDOR...WITH
PRIMARILY MVFR CONDITIONS IMPACTING BOTH KHUF AND KIND. LIGHT
NORTHWEST WINDS EXPECTED OVERNIGHT.
LIGHT SNOW WILL MOVE OFF TO THE EAST QUICKLY TUESDAY MORNING WITH
STEADILY IMPROVING CONDITIONS AT ALL TERMINALS. CEILINGS SHOULD
MIX OUT TO A SCATTERED VFR CU/STRATOCU DECK BY EARLY AFTERNOON.
MAIN IMPACT TO TERMINALS ON TUESDAY WILL BE WINDS AS TIGHTENING
SURFACE PRESSURE GRADIENT AND INCREASING FLOW THROUGH THE BOUNDARY
LAYER WILL SUPPORT WINDY CONDITIONS BY LATE MORNING. SOUTHWEST
SUSTAINEDS WILL INCREASE TO 15-20KTS WITH GUSTS AT 25-30KTS FROM
15-16Z CONTINUING INTO THE AFTERNOON.
&&
.IND WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
SYNOPSIS...50
NEAR TERM...TUCEK
SHORT TERM...50
LONG TERM....JH
AVIATION...RYAN
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
927 AM EST MON DEC 9 2013
.UPDATE...
THE NEAR TERM AND AVIATION SECTIONS HAVE BEEN UPDATED BELOW.
&&
.SYNOPSIS...
ISSUED AT 337 AM EST MON DEC 9 2013
HIGH PRESSURE WILL BRIEFLY MOVE INTO THE AREA TODAY BUT ANOTHER
UPPER DISTURBANCE WILL PROVIDE A CHANCE FOR SNOW FOR PARTS OF
CENTRAL INDIANA TONIGHT AND EARLY TUESDAY. AN AREA OF LOW PRESSURE
WILL THEN BRING A SMALL CHANCE FOR SNOW TO OTHER PARTS OF THE AREA
WEDNESDAY. COLDER AIR WILL THEN FLOW IN FOR THURSDAY.
TEMPERATURES WILL MODERATE BY THE WEEKEND BUT YET ANOTHER SYSTEM
WILL BRING CHANCES FOR PRECIPITATION FRIDAY NIGHT INTO SATURDAY.
&&
.NEAR TERM /TODAY/...
ISSUED AT 919 AM EST MON DEC 9 2013
INTRODUCING FLURRIES INTO FORECAST THROUGH MID AFTERNOON GIVEN
WEAK RADAR RETURNS COUPLED WITH SURFACE OBSERVED LIGHT SNOW
OCCURRING. DO NOT EXPECT ACCUMULATION THOUGH GIVEN NO VSBY DROP
ACCOMPANYING CURRENT SNOW AND FLAKES QUITE SMALL.
CLEARING ACROSS WC AND NW IL SHOULD WORK ITS WAY INTO WESTERN
COUNTIES BY LATE AFTERNOON AS HIGH PRESSURE BUILDS IN BUT RETURN
OF HIGH CLOUDS FROM SOUTHERN SYSTEMS APPROACH TO RETURN HIGHER
DECKS BY NIGHTFALL.
TEMPS TO HOLD FAIRLY STEADY THROUGH THE DAY GIVEN CLOUD DECK
HOLDING AND COLD ADVECTION BEGINNING TO TAKE PLACE.
&&
.SHORT TERM /TONIGHT THROUGH WEDNESDAY NIGHT/...
ISSUED AT 337 AM EST MON DEC 9 2013
FOCUS IS ON CHANCES FOR PRECIPITATION THROUGH THE PERIOD. MODELS ARE
IN DECENT AGREEMENT WITH THE BIG PICTURE SO USED A BLEND FOR MOST
PERIODS.
TONIGHT ISENTROPIC LIFT INCREASES ONCE AGAIN IN ADVANCE OF AN UPPER
WAVE. BEST FORCING AND MOISTURE LOOK TO BE CONFINED TO THE SOUTHERN
2/3 OF THE FORECAST AREA. THERE LOOKS TO BE SOME FRONTOGENETICAL
FORCING ACROSS MAINLY THE SOUTHERN HALF OF THE AREA AS WELL.
NAM IS FARTHEST NORTH WITH PRECIPITATION WITH OTHERS A BIT FARTHER
SOUTH. THIS LOOKS TO BE ANOTHER CASE WITH A VERY SHARP CUTOFF OF
POTENTIAL ACCUMULATING SNOW AND NO SNOW AT ALL. THUS CONFIDENCE IS
ONLY LOW TO MEDIUM IN NORTHERN PLACEMENT OF POPS...ESPECIALLY NORTH.
WILL GO DRY IN THE FAR NORTHWEST TONIGHT WITH A QUICK TRANSITION TO
HIGH CHANCE CATEGORY POPS SOUTH. IF NAM IS RIGHT WILL HAVE TO BUMP
TO LIKELY POPS ACROSS THE SOUTH WITH LATER FORECASTS. WILL CONTINUE
TO WATCH CLOSELY. POTENTIAL EXISTS FOR A QUICK INCH OR SO IN SOME
AREAS ACROSS THE SOUTH.
FORCING QUICKLY ENDS LATE TONIGHT INTO EARLY TUESDAY SO ONLY WENT
SLIGHT CHANCE POPS EARLY TUESDAY ACROSS THE FAR SOUTHEAST. OTHERWISE
CLOUDS WILL DECREASE TUESDAY AS SYSTEM EXITS. HOWEVER CLOUDS WILL
INCREASE ACROSS THE NORTH TUESDAY NIGHT AS THE NEXT SYSTEM
APPROACHES.
AN AREA OF LOW PRESSURE WILL MOVE ACROSS THE LOWER GREAT LAKES
WEDNESDAY. BEST FORCING AND MOISTURE REMAIN NORTH OF THE FORECAST
AREA...BUT LOOKS LIKE JUST ENOUGH MIGHT SNEAK INTO THE FAR NORTHERN
FORECAST AREA TO GO SLIGHT CHANCE POPS. DRY CONDITIONS WILL PREVAIL
WEDNESDAY NIGHT AS SYSTEM EXITS.
LOOKING AT TEMPERATURES...MAV LOOKS TOO COLD TONIGHT GIVEN EXPECTED
CLOUD COVER WITH NEXT SYSTEM. WENT CLOSER TO WARMER MET. ON TUESDAY
MAV LOOKS TOO WARM MANY AREAS GIVEN SOME COLD ADVECTION DURING PART
OF THE DAY. WENT CLOSER TO MET. AT OTHER TIMES USED A BLEND.
&&
.LONG TERM /THURSDAY THROUGH SUNDAY/...
ISSUED AT 333 AM EST MON DEC 9 2013
MODEL ENSEMBLES INDICATE HIGH PRESSURE WILL BE ACROSS THE OHIO
VALLEY THURSDAY WHICH WILL MOVE ON TO THE EAST FRIDAY. A RETURN
FLOW ON THE BACK SIDE OF THE HIGH WILL BRING A SLIGHT MODERATION OF
TEMPERATURES BY FRIDAY. OVERALL ONLY MADE A FEW TWEAKS TO ALL BLEND
TEMPERATURES THURSDAY AND FRIDAY.
MODELS INDICATE A COUPLE OF UPPER DISTURBANCES IN THE SOUTHERN
STREAM WILL AFFECT OUR WEATHER FRIDAY NIGHT AND SATURDAY WITH LOW
PRESSURE DEVELOPING OVER TENNESSEE AND TRACKING TOWARDS THE CENTRAL
APPALACHIANS BY SATURDAY EVENING. MODELS HAVE ALSO TRENDED A LITTLE
WETTER FOR FRIDAY NIGHT AND SATURDAY. 1000-700 MB THICKNESS FAVOR
SNOW OVER THE NORTHERN HALF TO TWO THIRDS OF OUR REGION AND A WINTRY
MIX TO THE SOUTH. THIS SHOULD MOVE OUT SATURDAY NIGHT...BUT SOME
MODELS INDICATE TRACE PRECIP AMOUNTS MAY LINGER INTO SATURDAY
NIGHT...SO WILL ADD 20 PERCENT POPS MOST AREAS. THE GFS REMAINS DRY
ON SUNDAY WHILE THE EURO INDICATES POSSIBLE SNOW SHOWERS SOME AREAS
WITH A STRONGER UPPER LOW MOVING INTO THE GREAT LAKES. WITH POOR
AGREEMENT BETWEEN MODELS WILL KEEP EVERYTHING DRY FOR NOW ON SUNDAY.
IN REGARDS TO TEMPERATURES OVER THE WEEKEND...WENT A LITTLE ABOVE
ALL BLEND TEMPERATURES FRIDAY AND SATURDAY NIGHT DUE TO LOTS OF
CLOUDS AND A LITTLE COLDER SUNDAY TO PARTIALLY MATCH THE COLDER
TREND OF THE NEW EURO. IN MOST CASES THESE WERE ONLY MINOR TWEAK TO
ALL BLEND TEMPERATURES.
&&
.AVIATION /DISCUSSION FOR THE 091500Z TAF UPDATE/...
ISSUED AT 921 AM EDT MON DEC 9 2013
CURRENT KIND RADAR SHOWING VERY LIGHT RETURNS WITH A FEW STATIONS
REPORTING FLURRIES. RAP SOUNDINGS INDICATING VERY WEAK INSTABILITY
UNDERNEATH THE INVERSION WHICH IS LIKELY CONTRIBUTING TO THE
FLURRIES. WILL INTRODUCE AT ALL SITES THROUGH 17Z BUT EXPECT NO
VISIBILITY RESTRICTIONS. OTHER CHANGE WAS TO INTRODUCE GUSTS THROUGH
THE AFTERNOON.
12Z DISCUSSION FOLLOWS...
ISSUED AT 605 AM EDT MON DEC 9 2013
MVFR CEILINGS WITH IFR CEILINGS POSSIBLE AT TIMES EARLY THIS MORNING
WILL IMPROVE TO VFR BY LATE AFTERNOON. THEN SOME AREAS MAY BECOME
MVFR CEILINGS SNOW LATE TONIGHT.
LOW PRESSURE OVER THE GREAT LAKES WILL CONTINUE MOVING NORTHEAST AS
HIGH PRESSURE OVER THE CENTRAL PLAINS BUILDS SLOWLY EASTWARD.
LOOK FOR A GRADUAL IMPROVEMENT IN THE CEILINGS BUT REMAINING MVFR
CEILINGS THROUGH MID AFTERNOON. AFTER THAT CEILINGS WILL RISE TO 3
THOUSAND AND LOWER CLOUDS MAY SCATTER OUT TOWARDS EVENING. A
WEATHER DISTURBANCE WILL TRACK INTO THE OHIO VALLEY LATE TONIGHT
BRINGING AN AREA OF SNOW OVER CENTRAL AND SOUTHERN SECTIONS. THIS
MAY RESULT IN MVFR OR POSSIBLY IFR CEILINGS AND SNOW SOME AREAS FROM
INDY AND SOUTHWARD LATE TONIGHT.
WINDS WILL BE FROM THE WEST UP TO 12 KNOTS TODAY AND 8 KNOTS OR LESS
TONIGHT.
&&
.IND WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...50
NEAR TERM...TUCEK
SHORT TERM...50
LONG TERM....JH
AVIATION...JH/RYAN
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
921 AM EST MON DEC 9 2013
.UPDATE...
AVIATION SECTION HAS BEEN UPDATED BELOW.
&&
.SYNOPSIS...
ISSUED AT 337 AM EST MON DEC 9 2013
HIGH PRESSURE WILL BRIEFLY MOVE INTO THE AREA TODAY BUT ANOTHER
UPPER DISTURBANCE WILL PROVIDE A CHANCE FOR SNOW FOR PARTS OF
CENTRAL INDIANA TONIGHT AND EARLY TUESDAY. AN AREA OF LOW PRESSURE
WILL THEN BRING A SMALL CHANCE FOR SNOW TO OTHER PARTS OF THE AREA
WEDNESDAY. COLDER AIR WILL THEN FLOW IN FOR THURSDAY.
TEMPERATURES WILL MODERATE BY THE WEEKEND BUT YET ANOTHER SYSTEM
WILL BRING CHANCES FOR PRECIPITATION FRIDAY NIGHT INTO SATURDAY.
&&
.NEAR TERM /TODAY/...
ISSUED AT 337 AM EST MON DEC 9 2013
A BAND OF LIGHT SNOW HAS DEVELOPED ALONG A WEAK SURFACE TROUGH
MOVING ACROSS CENTRAL INDIANA. THIS BAND OF SNOW WILL BE OUT OF MUCH
OF THE FORECAST AREA SHORTLY. BEHIND THE SNOW VISIBILITIES GENERALLY
IMPROVE WITH NO MENTION OF FREEZING DRIZZLE SEEN IN OBSERVATIONS.
BASED ON THIS HAVE DECIDED TO END WINTER WEATHER ADVISORY AT
ISSUANCE TIME. WILL CONTINUE WITH A SPECIAL WEATHER STATEMENT THOUGH
MENTIONING SLICK CONDITIONS PERSISTING EVEN THOUGH FREEZING
PRECIPITATION HAS ENDED. WILL KEEP FLURRIES IN THE GRIDS THROUGH 12Z.
OTHERWISE EXPECT A LITTLE DECREASE IN CLOUDS DURING THE DAY...BUT
STILL MOSTLY CLOUDY OVERALL. TEMPERATURES WILL FALL SOME IN COLD
ADVECTION THIS MORNING AND THEN REBOUND A BIT THIS AFTERNOON. BASED
ON EXPECTED TIME OF ARRIVAL OF COLDER AIR MOS HIGHS LOOK PRETTY GOOD
FOR TODAY.
&&
.SHORT TERM /TONIGHT THROUGH WEDNESDAY NIGHT/...
ISSUED AT 337 AM EST MON DEC 9 2013
FOCUS IS ON CHANCES FOR PRECIPITATION THROUGH THE PERIOD. MODELS ARE
IN DECENT AGREEMENT WITH THE BIG PICTURE SO USED A BLEND FOR MOST
PERIODS.
TONIGHT ISENTROPIC LIFT INCREASES ONCE AGAIN IN ADVANCE OF AN UPPER
WAVE. BEST FORCING AND MOISTURE LOOK TO BE CONFINED TO THE SOUTHERN
2/3 OF THE FORECAST AREA. THERE LOOKS TO BE SOME FRONTOGENETICAL
FORCING ACROSS MAINLY THE SOUTHERN HALF OF THE AREA AS WELL.
NAM IS FARTHEST NORTH WITH PRECIPITATION WITH OTHERS A BIT FARTHER
SOUTH. THIS LOOKS TO BE ANOTHER CASE WITH A VERY SHARP CUTOFF OF
POTENTIAL ACCUMULATING SNOW AND NO SNOW AT ALL. THUS CONFIDENCE IS
ONLY LOW TO MEDIUM IN NORTHERN PLACEMENT OF POPS...ESPECIALLY NORTH.
WILL GO DRY IN THE FAR NORTHWEST TONIGHT WITH A QUICK TRANSITION TO
HIGH CHANCE CATEGORY POPS SOUTH. IF NAM IS RIGHT WILL HAVE TO BUMP
TO LIKELY POPS ACROSS THE SOUTH WITH LATER FORECASTS. WILL CONTINUE
TO WATCH CLOSELY. POTENTIAL EXISTS FOR A QUICK INCH OR SO IN SOME
AREAS ACROSS THE SOUTH.
FORCING QUICKLY ENDS LATE TONIGHT INTO EARLY TUESDAY SO ONLY WENT
SLIGHT CHANCE POPS EARLY TUESDAY ACROSS THE FAR SOUTHEAST. OTHERWISE
CLOUDS WILL DECREASE TUESDAY AS SYSTEM EXITS. HOWEVER CLOUDS WILL
INCREASE ACROSS THE NORTH TUESDAY NIGHT AS THE NEXT SYSTEM
APPROACHES.
AN AREA OF LOW PRESSURE WILL MOVE ACROSS THE LOWER GREAT LAKES
WEDNESDAY. BEST FORCING AND MOISTURE REMAIN NORTH OF THE FORECAST
AREA...BUT LOOKS LIKE JUST ENOUGH MIGHT SNEAK INTO THE FAR NORTHERN
FORECAST AREA TO GO SLIGHT CHANCE POPS. DRY CONDITIONS WILL PREVAIL
WEDNESDAY NIGHT AS SYSTEM EXITS.
LOOKING AT TEMPERATURES...MAV LOOKS TOO COLD TONIGHT GIVEN EXPECTED
CLOUD COVER WITH NEXT SYSTEM. WENT CLOSER TO WARMER MET. ON TUESDAY
MAV LOOKS TOO WARM MANY AREAS GIVEN SOME COLD ADVECTION DURING PART
OF THE DAY. WENT CLOSER TO MET. AT OTHER TIMES USED A BLEND.
&&
.LONG TERM /THURSDAY THROUGH SUNDAY/...
ISSUED AT 333 AM EST MON DEC 9 2013
MODEL ENSEMBLES INDICATE HIGH PRESSURE WILL BE ACROSS THE OHIO
VALLEY THURSDAY WHICH WILL MOVE ON TO THE EAST FRIDAY. A RETURN
FLOW ON THE BACK SIDE OF THE HIGH WILL BRING A SLIGHT MODERATION OF
TEMPERATURES BY FRIDAY. OVERALL ONLY MADE A FEW TWEAKS TO ALL BLEND
TEMPERATURES THURSDAY AND FRIDAY.
MODELS INDICATE A COUPLE OF UPPER DISTURBANCES IN THE SOUTHERN
STREAM WILL AFFECT OUR WEATHER FRIDAY NIGHT AND SATURDAY WITH LOW
PRESSURE DEVELOPING OVER TENNESSEE AND TRACKING TOWARDS THE CENTRAL
APPALACHIANS BY SATURDAY EVENING. MODELS HAVE ALSO TRENDED A LITTLE
WETTER FOR FRIDAY NIGHT AND SATURDAY. 1000-700 MB THICKNESS FAVOR
SNOW OVER THE NORTHERN HALF TO TWO THIRDS OF OUR REGION AND A WINTRY
MIX TO THE SOUTH. THIS SHOULD MOVE OUT SATURDAY NIGHT...BUT SOME
MODELS INDICATE TRACE PRECIP AMOUNTS MAY LINGER INTO SATURDAY
NIGHT...SO WILL ADD 20 PERCENT POPS MOST AREAS. THE GFS REMAINS DRY
ON SUNDAY WHILE THE EURO INDICATES POSSIBLE SNOW SHOWERS SOME AREAS
WITH A STRONGER UPPER LOW MOVING INTO THE GREAT LAKES. WITH POOR
AGREEMENT BETWEEN MODELS WILL KEEP EVERYTHING DRY FOR NOW ON SUNDAY.
IN REGARDS TO TEMPERATURES OVER THE WEEKEND...WENT A LITTLE ABOVE
ALL BLEND TEMPERATURES FRIDAY AND SATURDAY NIGHT DUE TO LOTS OF
CLOUDS AND A LITTLE COLDER SUNDAY TO PARTIALLY MATCH THE COLDER
TREND OF THE NEW EURO. IN MOST CASES THESE WERE ONLY MINOR TWEAK TO
ALL BLEND TEMPERATURES.
&&
.AVIATION /DISCUSSION FOR THE 091500Z TAF UPDATE/...
ISSUED AT 921 AM EDT MON DEC 9 2013
CURRENT KIND RADAR SHOWING VERY LIGHT RETURNS WITH A FEW STATIONS
REPORTING FLURRIES. RAP SOUNDINGS INDICATING VERY WEAK INSTABILITY
UNDERNEATH THE INVERSION WHICH IS LIKELY CONTRIBUTING TO THE
FLURRIES. WILL INTRODUCE AT ALL SITES THROUGH 17Z BUT EXPECT NO
VISIBILITY RESTRICTIONS. OTHER CHANGE WAS TO INTRODUCE GUSTS THROUGH
THE AFTERNOON.
12Z DISCUSSION FOLLOWS.
MVFR CEILINGS WITH IFR CEILINGS POSSIBLE AT TIMES EARLY THIS MORNING
WILL IMPROVE TO VFR BY LATE AFTERNOON. THEN SOME AREAS MAY BECOME
MVFR CEILINGS SNOW LATE TONIGHT.
LOW PRESSURE OVER THE GREAT LAKES WILL CONTINUE MOVING NORTHEAST AS
HIGH PRESSURE OVER THE CENTRAL PLAINS BUILDS SLOWLY EASTWARD.
LOOK FOR A GRADUAL IMPROVEMENT IN THE CEILINGS BUT REMAINING MVFR
CEILINGS THROUGH MID AFTERNOON. AFTER THAT CEILINGS WILL RISE TO 3
THOUSAND AND LOWER CLOUDS MAY SCATTER OUT TOWARDS EVENING. A
WEATHER DISTURBANCE WILL TRACK INTO THE OHIO VALLEY LATE TONIGHT
BRINGING AN AREA OF SNOW OVER CENTRAL AND SOUTHERN SECTIONS. THIS
MAY RESULT IN MVFR OR POSSIBLY IFR CEILINGS AND SNOW SOME AREAS FROM
INDY AND SOUTHWARD LATE TONIGHT.
WINDS WILL BE FROM THE WEST UP TO 12 KNOTS TODAY AND 8 KNOTS OR LESS
TONIGHT.
&&
.IND WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
SYNOPSIS...50
NEAR TERM...50
SHORT TERM...50
LONG TERM....JH
AVIATION...JH/RYAN
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 GOODLAND KS
445 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 00Z TAFS THROUGH 00Z WEDNESDAY EVENING)
ISSUED AT 445 PM MST TUE DEC 10 2013
VFR CONDITIONS ARE EXPECTED FOR THE 24 HOUR FORECAST PERIOD. A
WEAK COLD FRONT WILL REACH KGLD AND KMCK AROUND 01Z AND RESULT IN
A BRIEF INCREASE IN WINDS TO AROUND 12-15KT WITH HIGHER GUSTS
POSSIBLE. WINDS WILL LESSEN LATE THIS EVENING AND THROUGH THE
OVERNIGHT. LIGHT WINDS AND MOSTLY CLEAR CONDITIONS ARE EXPECTED
TOMORROW.
&&
.GLD WATCHES/WARNINGS/ADVISORIES...
KS...NONE.
CO...NONE.
NE...NONE.
&&
$$
SHORT TERM...DR
LONG TERM...024
AVIATION...BRB
AREA FORECAST DISCUSSION...UPDATED
NWS JACKSON KY
435 PM EST MON DEC 9 2013
.SHORT TERM...(THIS EVENING THROUGH TUESDAY NIGHT)
ISSUED AT 435 PM EST MON DEC 9 2013
20Z SFC ANALYSIS SHOWS THE ARCTIC BOUNDARY HOLDING ON JUST TO OUR
SOUTHEAST AWAITING THE NEXT WAVE OF PCPN TO MOVE UP ALONG IT FROM THE
SOUTH. LOW CLOUDS ARE FOUND THROUGH MOST OF EAST KENTUCKY WITH JUST
SOME SMALL BREAKS RIGHT ALONG THE SPINE OF THE APPALACHIANS. UNDER
THESE AND CLOSER TO THE FRONT...TEMPERATURES ARE SIGNIFICANTLY
MILDER THAN THE REST OF THE AREA. AS A RESULT...READINGS RANGE FROM
THE MID AND UPPER 40S NEAR VIRGINIA TO THE LOW 30S NORTH OF
INTERSTATE 64. DEWPOINTS...MEANWHILE...ARE IN THE UPPER 20S
NORTHWEST TO LOWER 40S IN THE FAR SOUTHEAST.
THE MODELS REMAIN IN SOME FLUX...STILL AT THIS LATE HOUR...REGARDING
THE TANDEM MID LEVEL WAVES THAT WILL CROSS THE OHIO VALLEY ON
TUESDAY. THE SOUTHERN ONE WILL HAVE THE MOST IMPACT ON THE AREA LATER
TONIGHT BUT MAY NOT COMPLETELY PHASE WITH THE CLIPPER COMING IN FROM
THE NORTH. BECAUSE OF THIS...THE RESULTING WEATHER HAS BEEN SHIFTING
IN THE MODEL SOLUTIONS WITH EACH RUN. REGARDLESS...THE COMBINED
TROUGH WILL SWEEP THROUGH THE OHIO VALLEY AND CENTRAL APPALACHIANS BY
00Z WEDNESDAY WITH FAST...FLAT FLOW TO FOLLOW. A GENERAL MODEL BLEND
WAS USED FOR THE FORECAST WITH THE 12Z NAM AND GFS TAKING THE LEAD...
ALTHOUGH THE HRRR WAS ALSO INCLUDED FOR THE PCPN ONSET AND TYPE
EARLY.
SENSIBLE WEATHER WILL FEATURE A QUICK HIT OF PCPN AS THE LAST SFC
WAVE MOVES NORTHEAST ALONG THE TIGHTENING ARCTIC BOUNDARY JUST TO
OUR SOUTHEAST. EXPECT THE PCPN TO MOVE BACK IN AROUND MIDNIGHT
STARTING ALONG THE TENNESSEE BORDER IN THE FAR SOUTHWEST AND QUICKLY
SPREADING NORTHEAST WITH TIME. THE LATEST MODELS ARE TARGETING THE
SOUTHEAST 2/3RDS OF THE CWA FOR A QUARTER INCH OR SO OF QPF AND
LIGHTER AMOUNTS TAPERING QUICKLY TO THE NORTHWEST. THE NORTHERN
PORTION OF THIS HYBRID CLIPPER/WAVE WILL LIKELY HAVE HIGHER SNOW
RATIOS TO COMPENSATE FOR THE LESSER QPF THERE. ACROSS THE FAR
SOUTHEAST...THERE WILL BE A BETTER CHANCE OF SLEET MIXING IN WITH THE
SNOW AT THE ONSET SO HAVE CUT THE SNOW AMOUNTS IN THIS AREA. THE SNOW
WILL LIKELY COME DOWN QUICK FOR SEVERAL HOURS ACROSS THE AREA RIGHT
BEFORE THE MORNING-SCHOOL COMMUTE. ACCORDINGLY...WE HAVE HOISTED A
WSW FROM MIDNIGHT THROUGH THE MORNING ACROSS THE AREA...LINGERING THE
ADVISORY IN THE FAR SOUTHEAST THROUGH MID AFTERNOON TUESDAY. THE SNOW
PULLS AWAY QUICKLY AND DRIER AIR BEHIND THE FINALLY DEPARTING ARCTIC
BOUNDARY WILL CLEAR THE SKY AND POPS SETTING THE STAGE FOR A VERY
COLD NIGHT INTO WEDNESDAY MORNING.
USED THE CONSSHORT TO BASE THE TEMPS AND TD ON THROUGH 18Z TUESDAY...
CONSALL THEREAFTER...WHILE ALLOWING THE DIURNAL FROM THE NAM12 TO
GUIDE THE HOURLY TEMPS THROUGH THE SHORT TERM...TOO. BCCONSSHORT WAS
USED AS A STARTING POINT FOR WINDS THROUGH 18Z AND THE BCCONSALL
AFTER THAT. AS FOR POPS...ENDED UP CLOSEST TO THE SLIGHTLY HIGHER MET
NUMBERS ACROSS THE AREA TONIGHT INTO TUESDAY AND BASICALLY KEPT
THINGS DRY ON TUESDAY NIGHT.
.LONG TERM...(WEDNESDAY THROUGH MONDAY)
ISSUED AT 257 PM EST MON DEC 9 2013
MODELS ARE IN REASONABLE AGREEMENT THROUGH THE WEEK AND INTO THE
UPCOMING WEEKEND WITH ONLY SOME SMALL DIFFERENCES. CONFIDENCE IS
INCREASING AROUND THE UPCOMING STORM FOR FRIDAY NIGHT AND SATURDAY.
HIGH PRESSURE WILL FINALLY MAKE A RETURN FOR WEDNESDAY WITH A FULL
DAY OF SUNSHINE. A FAST MOVING VORT MAX WILL TEMPORARILY SUPPRESS
THE HIGH TO THE SOUTH AS IT PUSHES A COLD FRONT ACROSS EASTERN
KENTUCKY. MOISTURE REMAINS VERY LIMITED WITH THIS FEATURE AND AT
BEST A PERIOD OF FLURRIES COULD OCCUR. HIGH PRESSURE WILL REBUILD
OVER THE AREA FROM THURSDAY INTO FRIDAY. A SHARP MID LEVEL TROUGH
WILL EJECT OUT OF THE SOUTHWEST FRIDAY NIGHT INTO SATURDAY...WITH A
SURFACE LOW TRACKING ACROSS THE REGION. RIGHT NOW IT LOOKS LIKE THE
TRACK SHOULD TAKE IT RIGHT OVER SOUTHEAST KENTUCKY WITH THE WARM
SECTOR SURGING INTO THE AREA LATE FRIDAY NIGHT. WHILE A PERIOD OF
SNOW/SLEET MAY BE POSSIBLE AT THE ONSET...ESPECIALLY ACROSS THE
NORTH...WE SHOULD SEE A QUICK TRANSITION OVER TO ALL RAIN. RAIN WILL
CONTINUE INTO SATURDAY. AS THE SYSTEM DEPARTS...COLD AIR WILL WRAP
BACK INTO EASTERN KENTUCKY WITH PRECIPITATION CHANGING OVER TO SNOW
SATURDAY NIGHT. AT THIS TIME...MOISTURE AND LIFT APPEARS TO BE
FAIRLY LIMITED WITH UPSLOPE FLOW...SO ANY ACCUMULATIONS WILL LIKELY
BE SMALL AND MAYBE CONFINED TO JUST THE HIGHER ELEVATIONS.
DRIER...BUT COLDER WEATHER WILL THEN BE SEEN INTO EARLY NEXT WEEK.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z TUESDAY AFTERNOON)
ISSUED AT 205 PM EST MON DEC 9 2013
ALTHOUGH DRIER AIR IS FILTERING INTO THE AREA CIGS ARE STILL QUITE
LOW. HAVE LIMITED THEIR RECOVER TO LATE THIS AFTERNOON AND EARLY THIS
EVENING. CONFIDENCE IN THE DETAILS OF SNOW DEVELOPING ACROSS THE
AREA OVERNIGHT HAS INCREASED WITH BETTER MODEL AGREEMENT.
ACCORDINGLY...HAVE HIT ALL THE TAFS WITH A PERIOD OF SNOW...LOW
CIGS...AND VIS FROM SOMETIME AFTER MIDNIGHT UNTIL JUST AFTER DAWN ON
TUESDAY. EXPECT CONDITIONS TO IMPROVE BUT CIGS WILL PROBABLY BE
MVFR INTO THE FIRST PART OF THE AFTERNOON. WINDS WILL BE WEST TO
NORTHWEST THROUGH THE PERIOD AT 5 TO 10 KTS...BUT DURING ANY HEAVIER
BOUTS OF SNOW THERE MAY BE A BRIEF PICK UP WITH GUSTS TO 15 KTS OR
SO.
&&
.JKL WATCHES/WARNINGS/ADVISORIES...
WINTER WEATHER ADVISORY FROM MIDNIGHT TONIGHT TO NOON EST
TUESDAY FOR KYZ044-050>052.
WINTER WEATHER ADVISORY FROM MIDNIGHT TONIGHT TO 2 PM EST
TUESDAY FOR KYZ058>060-068-069-079-080-083-084-104-106>109-111-
112-114.
WINTER WEATHER ADVISORY FROM MIDNIGHT TONIGHT TO 4 PM EST
TUESDAY FOR KYZ085>088-110-113-115>120.
&&
$$
SHORT TERM...GREIF
LONG TERM...KAS
AVIATION...GREIF
AREA FORECAST DISCUSSION
NWS TAUNTON MA
100 AM EST MON DEC 9 2013
.SYNOPSIS...
LOW PRESSURE LIFTING NORTH FROM THE MID ATLANTIC WILL BRING MIXED
PRECIP LATE TONIGHT INTO MONDAY. MAINLY DRY...BUT UNSEASONABLY
COLD AND BLUSTERY WEATHER IS EXPECTED FOR THE REST OF THE UPCOMING
WORK WEEK. WE WILL HAVE TO KEEP AN EYE ON THE POTENTIAL FOR A
PERIOD OF LIGHT SNOW ON TUESDAY...MAINLY SOUTH OF THE MASSACHUSETTS
TURNPIKE.
&&
.NEAR TERM /UNTIL 6 AM THIS MORNING/...
1 AM UPDATE...
AREAS OF LIGHT SNOW AND FREEZING DRIZZLE BREAKING OUT ACROSS SNE.
DRY AIR IN THE SNOW GROWTH REGION AND LIGHT PRECIP RESULTING IN
AREAS OF FZDZ...BUT EXPECT PRECIP TO BECOME SNOW AS STRONGER OMEGA
AND STEADIER PRECIP DEVELOPS. HOWEVER...WARMER AIR ALOFT HAS
ALREADY REACHED THE SW CT COAST WITH FZRA NOW AT BDR. THIS WILL
BE LIFTING NE SO THE SNOW NEAR THE COAST WILL BE SHORT
LIVED...CHANGING TO SLEET/FZRA 08-10Z.
LATEST NAM STILL INDICATING POTENTIAL FOR MESOSCALE BANDING MOVING
UP ALONG THE S COAST AND CAPE/ISLANDS THROUGH 09Z AS STRONG 850
MB FRONTOGENESIS DEVELOPS WITHIN TIGHTENING THERMAL GRADIENT AND
DECENT LIFT IN THE SNOW GROWTH REGION. HOWEVER...THIS IS THE TIME
THE WARM NOSE ABOVE 800 MB MOVES IN SO PRECIP WILL LIKELY BE
CHANGING TO SLEET/FZRA/RA DURING THIS TIME WHICH WILL LIMIT SNOW
ACCUM TO A COATING TO POSSIBLY AN INCH.
&&
.SHORT TERM /2 AM THIS MORNING THROUGH 6 PM TUESDAY/...
AN OPEN-WAVE TROUGH ACROSS THE GREAT LAKES REGION HAS BEGUN TO
INTERACT WITH THE BROADER SUB-TROPICAL FLOW ACROSS THE EASTERN
CONUS. INFLECTION ALONG THE COLLOCATED TIGHT THERMAL GRADIENT HAS
SUBSEQUENTLY RESULTED IN A WEAK AREA OF LOW PRESSURE PRESENTLY OFF
THE MID-ATLANTIC WHICH WILL DRIFT NORTHEASTWARD ACROSS CAPE COD
BRINGING WITH IT A WINTRY MIX OF SNOW...SLEET...AND FREEZING RAIN
FOR SOUTHERN NEW ENGLAND DURING THE TIMEFRAME /ESPECIALLY THE MONDAY
MORNING COMMUTE/.
HAVE GREATER CONFIDENCE WITH COLDER SOLUTIONS. WITH BROAD AGREEMENT
AND RUN-TO-RUN CONTINUITY FROM THE ECMWF...PREFER THE MESO-NAM AND
WRF-MODEL SOLUTIONS WHICH CAPTURE THE COLD-AIR DAMMING PROCESSES
THROUGH THE CONNECTICUT RIVER VALLEY /SEE 1000-850 THICKNESSES/.
TRENDS ARE NOTEWORTHY WITHIN THE LATEST HRRR RUNS. BUT OVERALL THERE
IS STILL PLENTY OF UNCERTAINTY CONCERNING THERMAL PROFILES AND THE
ACCOMPANYING TRANSITION PROCESS OF WINTRY WEATHER TO PLAIN RAIN.
THAT BEING SAID...THERE IS A LOT TO CONSIDER. WITH H975 AGEOSTROPHIC
FLOW OUT OF THE INTERIOR NORTH WITH A WEAK LOW TRACKING ACROSS THE
CAPE...NOT EXPECTING EASTERLY ONSHORE FLOW NORTH OF THE LOW TO SCOUR
OUT INTERIOR SURFACE COLD AIR EFFECTIVELY. EXPECT PREVAILING
NORTHERLY COLD-AIR DRAINAGE FLOW...JAMMING UP THROUGHOUT INTERIOR
VALLEYS /ESPECIALLY THE CT RIVER VALLEY/. 2M FORECASTED TEMPERATURES
TAKEN MAINLY FROM MESO-NAM/WRF-MODEL SOLUTIONS. THOUGH THE EASTERLY
ONSHORE FLOW WILL RESULT IN A FASTER TRANSITION OF PRECIPITATION
TYPES ACROSS EAST COASTAL PLAIN IN THE MORNING...EXPECTING A WINTRY
MIX TO LAST LONGER ACROSS THE INTERIOR INTO THE MIDDAY AND POSSIBLY
THE AFTERNOON HOURS. UPSTREAM TRENDS ACROSS INTERIOR MID-ATLANTIC
SHOW THIS PROCESS ALREADY ONGOING WHICH ADD FURTHER CONFIDENCE THAT
COLD-AIR DAMMING OVER THE INTERIOR WILL BE A BIG ISSUE AS TO WINTER
WEATHER OUTCOMES.
PRECIPITATION AND SNOW/ICE AMOUNTS REMAIN A CHALLENGE...AND LIKELY
THERE ARE ALWAYS SURPRISES IN STORE WITH SYSTEMS SUCH AS THESE.
CONSIDERING THE AFOREMENTIONED SPATIAL AND TEMPORAL CHALLENGES IN THE
PRECIPITATION TRANSITION...IMPACTING ACCUMULATIONS AT THE SURFACE...
ANOTHER POINT OF CONCERN IS UPON PRECIPITATION AMOUNTS. EVALUATING
THE ATMOSPHERE...FORCING IS MAINLY WITHIN LOW-LEVELS WITH LITTLE
INDICATION OF DEEP-LAYER ASCENT ALBEIT SOME BROAD-SCALE DIFFLUENCE
ALOFT. YET SREF V-WIND ANOMALIES AT H85 ARE +2 STANDARD-DEVIATIONS
AND NOTING UPSTREAM TRENDS OVER THE MID-ATLANTIC...THERE IS THE
DISTINCT POSSIBILITY FOR A MESO-SCALE BAND OF SNOW ACROSS SOUTHERN
NEW ENGLAND COLLOCATED WITH THE TIGHT H85 THERMAL GRADIENT WHERE
STRONG LOW-LEVEL CONVERGENCE IS MODELED TO LIFT THROUGH BETTER SNOW-
GROWTH REGIONS. THERE IS SOME SIGNAL WITHIN NEAR-TERM MESOSCALE
SOLUTIONS...ALBEIT CHAOTIC. IT IS ENTIRELY PLAUSIBLE TO SEE AREAS IN
PROXIMITY TO THE SOUTH-COAST OF SEEING A COUPLE OF INCHES OF SNOW IN
A SHORT PERIOD OF TIME DURING THE EARLY ONSET BEFORE TRANSITIONING
TO RAIN.
AS SUCH...WILL TAKE 1-2 INCH ACCUMULATIONS DOWN TO THE SOUTH-COAST.
WILL HAVE 2-4 INCHES FOR PORTIONS OF NORTH AND WEST MA AND SOUTHERN
NH. ICE ACCUMULATIONS UP TO A TENTH OF AN INCH EXPECTED ALONG AND
EAST OF THE EASTERN COASTAL PLAIN...EAST OF THE I-95/I-495 BELTWAY.
TOTAL LIQUID PRECIPITATION AMOUNTS AROUND 0.4 INCHES WITH THE
HEAVIEST AMOUNTS JUST OFF THE SOUTH-COAST.
EXPECT ACCUMULATIONS TO BEGIN THIS EVENING AND CONTINUE THROUGH THE
MORNING COMMUTE. WILL SEE A GRADUAL TRANSITION OF FROZEN P-TYPES
BACK INTO THE INTERIOR BEGINNING AROUND 6-8 AM...WITH LOCATIONS
ACROSS WESTERN AND NORTHERN MA AND SOUTHERN NH SEEING THE LONGEST
PERIOD OF A WINTRY MIX....EAST-COAST TRANSITIONING QUICKEST. HAVE
LENGTHENED THE WINTER- WEATHER ADVISORY FOR HARTFORD COUNTY CT
WITH THE EXPECTATION OF COLD-AIR DRAINAGE PROCESSES. IMPACTS IN
THE WINTER WEATHER ADVISORY...BUT IN BREVITY...EXPECT A MESSY
MONDAY MORNING COMMUTE.
&&
.LONG TERM /TUESDAY NIGHT THROUGH SUNDAY/...
HIGHLIGHTS...
* PERIOD OF LIGHT SNOW POSSIBLE SOUTH OF MA PIKE ON TUE
* MAINLY DRY AND UNSEASONABLY COLD WED THROUGH FRI
* LOW CONFIDENCE FORECAST NEXT WEEKEND
DETAILS...
MONDAY NIGHT...
OTHER THAN PERHAPS A LEFT OVER SPOT SHOWER IN THE EARLY EVENING...
DRY WEATHER EXPECTED. A COLD FRONT SWINGS THROUGH THE REGION EARLY
IN THE EVENING. TEMPS WILL ACTUALLY RISE ABOVE FREEZING ACROSS
PORTIONS OF THE INTERIOR THAT HAVE BEEN JAMMED IN SHALLOW COLD AIR
DURING THE DAY MONDAY. THE REASON FOR THIS IS THAT WARMER MID
LEVEL AIR WILL BE TEMPORARILY MIXED DOWN...AS WINDS SHIFT TO THE
WEST. THIS SHOULD ALLOW ANY LEFTOVER ICY CONDITIONS ON ROADWAYS TO
MELT. COLDER AIR WILL FINALLY BEGIN WORKING BACK INTO THE REGION
OVERNIGHT...WITH LOWS BY DAYBREAK BACK INTO THE 20S ACROSS THE
INTERIOR. THE COASTAL PLAIN SHOULD ONLY SEE LOWS REACH THE LOWER
TO MIDDLE 30S.
TUESDAY...
THE MAIN CONCERN IS THE CHANCES FOR A PERIOD OF LIGHT SNOW ON
TUESDAY...MAINLY SOUTH OF THE MA TURNPIKE. A WEAK WAVE OF LOW
PRESSURE WILL BE PASSING WELL TO OUR SOUTH...BUT AN APPROACHING
SHORTWAVE BACKS THE UPPER LEVEL FLOW. IT PLACES US UNDERNEATH A
POTENT JET STREAK WHICH RESULTS IN A PERIOD OF DECENT MID LEVEL
LIFT. WILL BE FIGHTING LOW LEVEL DRY AIR SO NOT EXPECTING A LOT OF
PRECIP...BUT A PERIOD OF LIGHT SNOW IS STILL POSSIBLE SOUTH OF MA
TURNPIKE ESPECIALLY NEAR THE SOUTH COAST. PERHAPS ITS MILD ENOUGH
FOR MIXED PRECIP AT THE ONSET ACROSS CAPE/ISLANDS...BUT SHOULD
TURN OVER TO ALL LIGHT SNOW. A COATING TO PERHAPS 1 INCH OF SNOW IS
POSSIBLE IN A FEW LOCATIONS. THERE ALSO IS A LOW PROBABILITY OF A BIT
MORE SNOW THAN THAT NEAR THE SOUTH COAST...BUT MOST GUIDANCE DOES NOT
SUPPORT THAT AT THIS TIME.
WEDNESDAY THROUGH FRIDAY...
NORTHWEST FLOW ALOFT WILL RESULT IN UNSEASONABLY COLD WEATHER FOR
SOUTHERN NEW ENGLAND. THERE ARE SOME MODEL DISCREPANCIES ON THE
TIMING OF REINFORCING SHOTS OF COLD AIR...HENCE UNCERTAINTIES ON
WHICH DAY WILL BE THE COLDEST. MAINLY DRY WEATHER DOMINATES OVER
THIS TIME PERIOD...BUT CAN/T RULE OUT A BRIEF PASSING FLURRY/SNOW
SHOWER WITH SOME MOISTURE STARVED NORTHERN STREAM ENERGY/FRONTAL
PASSAGES. IT ALSO WILL BE WINDY AT TIMES...SO IT CERTAINLY WILL
FEEL WINTERLIKE.
SATURDAY AND SUNDAY...
FORECAST CONFIDENCE IS VERY LOW OVER THIS TIME. THE ONE THING WILL
HAVE TO WATCH NEXT WEEKEND IS THE TRACK A WAVE OF LOW PRESSURE TO
OUR SOUTH. MOST MODELS SUGGEST THAT THE SYSTEM WILL PASS FAR
ENOUGH SOUTH TO SPARE OUR REGION OF SIGNIFICANT PRECIP.
HOWEVER...SOME MODELS SUGGEST THE LARGE HIGH TO OUR NORTH MAY
EVENTUALLY RESULT IN ONSHORE FLOW...BRINGING THE POTENTIAL FOR
SOME LIGHT WINTRY PRECIPITATION. OTHER GUIDANCE SUGGESTS SOUTHWEST
FLOW ALOFT MAY RESULT IN SOME OVER RUNNING PRECIPITATION. ALL IN
ALL...VERY LOW CONFIDENT FORECAST FOR NEXT WEEKEND.
&&
.AVIATION /06Z MONDAY THROUGH FRIDAY/...
FORECASTER CONFIDENCE LEVELS...
LOW...LESS THAN 30 PERCENT.
MODERATE...30 TO 60 PERCENT.
HIGH...GREATER THAN 60 PERCENT.
NEAR-TERM /THROUGH TONIGHT/...
HIGH CONFIDENCE IN WIDESPREAD IFR CONDITIONS DEVELOPING AS PRECIP
MOVES ACROSS THE REGION. LOWER CONFIDENCE IN TIMING OF PTYPE
TRANSITIONS. EXPECT SNOW CHANGING TO SLEET/FZRA FROM SOUTH TO
NORTH THIS MORNING AND EVENTUALLY TO PLAIN RAIN IN THE COASTAL
PLAIN. INTERIOR TERMINALS WILL LIKELY HAVE TO DEAL WITH AN
EXTENDED PERIOD OF FREEZING RAIN/DRIZZLE INTO THE AFTERNOON.
MINOR SNOW ACCUM UP TO 2 INCHES POSSIBLE. CONDITIONS EXPECTED TO
IMPROVE TO VFR LATER TONIGHT.
KBOS TAF...HIGH CONFIDENCE IN MVFR/IFR DEVELOPING. LOW CONFIDENCE
IN TIMING OF PTYPE TRANSITIONS.
KBDL TAF...HIGH CONFIDENCE IN MVFR/IFR DEVELOPING. LOW CONFIDENCE
IN TIMING OF PTYPE TRANSITIONS.
OUTLOOK...MONDAY NIGHT THROUGH FRIDAY...
MONDAY NIGHT...MODERATE TO HIGH CONFIDENCE. LEFT OVER MVFR-IFR
CONDITIONS EARLY IN THE EVENING IMPROVE TO VFR BEHIND A COLD FRONT.
TUESDAY...LOW CONFIDENCE. A PERIOD OF MVFR-IFR CONDITIONS POSSIBLE
SOUTH OF THE MA TURNPIKE IN A ROUND OF LIGHT SNOW. OTHERWISE...VFR
CONDITIONS FOR THE REST OF THE TIME.
WEDNESDAY THROUGH FRIDAY...MODERATE TO HIGH CONFIDENCE. VFR
CONDITIONS DOMINATE WITH GUSTY WNW WINDS AT TIMES.
&&
.MARINE...
FORECASTER CONFIDENCE LEVELS...
LOW...LESS THAN 30 PERCENT.
MODERATE...30 TO 60 PERCENT.
HIGH...GREATER THAN 60 PERCENT.
NEAR-TERM /THROUGH MONDAY/...HIGH CONFIDENCE.
NORTHERLY WINDS OVER THE WATERS WILL VEER EAST-SOUTHEASTERLY WITH
TIME GUSTING 25 TO 30 KTS DURING THE DAY MONDAY AS AN AREA OF LOW
PRESSURE CROSSES INTO SOUTHERN NEW ENGLAND. WITH THE LOW/S PASSAGE
EXPECT WINDS TO BACK MORE SOUTHERLY.
PROLONGED PERIOD OF FETCH WILL RESULT IN SEAS OF 6 TO 8 FEET
ACROSS THE OUTER WATERS IMPACTING THE EAST- FACING ATLANTIC
BEACHES. SMALL CRAFT ADVISORIES IN EFFECT FOR ALL LOCATIONS EXCEPT
INNER BAYS.
OUTLOOK...MONDAY NIGHT THROUGH FRIDAY...HIGH CONFIDENCE.
THE GENERAL IDEA IS THAT THE PASSAGE OF A COUPLE OF STRONG COLD
FRONTS WILL RESULT IN PERSISTENT WEST TO NORTHWEST WINDS OVER THIS
TIME. GIVEN THE STRONG COLD ADVECTION OVER THE WATERS...SCA WIND
GUSTS ARE EXPECTED OVER MUCH OF THIS TIME PERIOD OVER THE OPEN
WATERS. WE MAY EVEN SEE A BRIEF GALE FOR A TIME ON WEDNESDAY. THERE
ALSO WILL BE LULLS IN THE WIND...BUT TIMING THAT THIS FAR OUT IS
IMPOSSIBLE.
&&
.BOX WATCHES/WARNINGS/ADVISORIES...
CT...WINTER WEATHER ADVISORY UNTIL 10 PM EST THIS EVENING FOR
CTZ002.
WINTER WEATHER ADVISORY UNTIL 1 PM EST THIS AFTERNOON FOR
CTZ003-004.
MA...WINTER WEATHER ADVISORY UNTIL 10 PM EST THIS EVENING FOR
MAZ002>004-008>011-026.
WINTER WEATHER ADVISORY UNTIL 1 PM EST THIS AFTERNOON FOR
MAZ005-012>014-017.
NH...WINTER WEATHER ADVISORY UNTIL 10 PM EST THIS EVENING FOR
NHZ011-012-015.
RI...WINTER WEATHER ADVISORY UNTIL 1 PM EST THIS AFTERNOON FOR
RIZ001>004-006.
MARINE...SMALL CRAFT ADVISORY FROM 4 AM EARLY THIS MORNING TO 10 PM EST
THIS EVENING FOR ANZ231>234.
SMALL CRAFT ADVISORY UNTIL 7 AM EST TUESDAY FOR ANZ235-237-
254>256.
SMALL CRAFT ADVISORY FROM 7 AM THIS MORNING TO 7 AM EST
TUESDAY FOR ANZ250-251.
&&
$$
SYNOPSIS...FRANK/SIPPRELL
NEAR TERM...KJC
SHORT TERM...SIPPRELL
LONG TERM...FRANK
AVIATION...KJC/FRANK
MARINE...FRANK/SIPPRELL
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
614 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 00Z TAFS THROUGH 00Z WEDNESDAY EVENING)
ISSUED AT 614 PM EST TUE DEC 10 2013
KIWD...EXPECT MVFR CONDITIONS TO LAST THROUGH THE FORECAST PERIOD
WITH LAKE EFFECT SNOW SHOWERS CONTINUING.
KCMX...EXPECT IFR TO LIFR CONDITIONS THROUGH THE FORECAST PERIOD
WITH HEAVY SNOW BANDS PASSING THROUGH. WITH GUSTY WINDS...THE
BLOWING SNOW WILL BE THE MAIN FACTOR IN THE LOW VISIBILITIES.
KSAW...VFR CONDITIONS WILL CONTINUE THRU THE FORECAST PERIOD.
DOWNSLOPE NATURE OF THE W WIND AND RELATIVE DRYNESS OF THE AIRMASS
SHOULD MAINTAIN THE VFR WX AT THIS SITE EVEN IF SOME FLURRIES MAKE
IT INTO THE AREA ON WED.
&&
.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 /5 AM CST/ THURSDAY
FOR LSZ162-240>245-248>251-263>265.
LAKE MICHIGAN...
HEAVY FREEZING SPRAY WARNING UNTIL 6 AM EST WEDNESDAY FOR LMZ221-
248-250.
&&
$$
SHORT TERM...ROLFSON
LONG TERM...KF
AVIATION...07
MARINE...KF
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
427 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 18Z TAFS THROUGH 18Z TUESDAY AFTERNOON)
ISSUED AT 117 PM EST MON DEC 9 2013
KIWD...EXPECT MVFR CIGS AND -SN IN WSW FLOW THROUGH MUCH OF THIS AFTERNOON.
CONDITIONS SHOULD IMPROVE TO VFR THIS EVENING AS WINDS BACK MORE SW.
MVFR CONDITIONS IN LIGHT SNOW RETURN LATE TONIGHT WITH APPROACH OF
NEXT DISTURBANCE THE NOTRHERN PLAINS.
KCMX...IFR CONDITIONS WILL LOWER TO LIFR/VLIFR VSBY IN MODERATE TO
HEAVY LAKE EFFECT SNOW THIS AFTERNOON AS WSW WINDS VEER TO THE W AND
BECOME GUSTY. THIS WILL CONTINUE INTO THE EVENING HOURS BUT SHOULD
IMPROVE BY LATE EVENING. CONDITIONS WILL IMPROVE AGAIN TO MVFR LATE
TONIGHT AS THE HEAVIER LES BANDS SHIFT NORTH OF THE AREA.
KSAW...MVFR CIGS THIS AFTERNOON ARE EXPECTED THAT WILL LIFT BACK TO
VFR AS A DISTUBANCE MOVES TO THE EAST OF THE AREA. THE NEXT
SHORTWAVE TROUGH MOVING INTO THE AREA TUE MORNING WILL BRING ANOTHER
PERIOD OF MVFR CIGS WITH SOME LIGHT SNOW SHOWERS OR FLURRIES.
&&
.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 10 PM EST /9 PM CST/ THIS EVENING FOR
LSZ241>243-246-247.
GALE WARNING UNTIL MIDNIGHT EST TONIGHT FOR LSZ263.
LAKE MICHIGAN...
GALE WARNING UNTIL 10 PM EST THIS EVENING FOR LMZ221-248-250.
&&
$$
SHORT TERM...JLB
LONG TERM...SRF
AVIATION...JLB
MARINE...JLB
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
417 PM EST MON DEC 9 2013
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 551 AM EST MON DEC 9 2013
WV IMAGERY AND RUC ANALYSIS STILL SHOWING A BROAD MID/UPPER LEVEL
TROUGH OVER THE WRN CONUS RESULTING IN WSW FLOW FROM THE PLAINS INTO
THE GREAT LAKES. THERE ARE SEVERAL SHORTWAVES OF NOTE FOR THE SHORT
TERM.
ONE SHORTWAVE MOVING ACROSS LAKE MI INTO LOWER MI AND ITS
ASSOC SFC LOW PRODUCED LIGHT SNOW ACROSS THE CWA LAST NIGHT INTO THE
EARLY MORNING. MOST OF THE AREA RECEIVED GENERALLY NO MORE THAN AN
INCH OF SYSTEM SNOW...ALTHOUGH SOME LOCATIONS ALONG LAKE MI LIKELY
RECEIVED 2 TO LOCALLY 4 INCHES OF SNOW DUE TO LAKE ENHANCEMENT OF
SNOW OFF LAKE MI. MQT RADAR WAS SHOWING A MORE PROMINENT BAND OF
LAKE ENHANCED SNOW FROM NEAR COOKS/MANISTIQUE AREA NORTH TO
SHINGLETON IN THE PAST FEW HOURS ALTHOUGH IT LOOKS LIKE THIS BAND
MAY BE WEAKENING NOW AS BEST FORCING FOR ENHANCEMENT APPEARS TO BE
LIFTING EAST WITH THE SHORTWAVE. DUE TO ISOLATED NATURE OF THIS
BAND DECIDED TO ONLY KEEP WINTER WX ADVISORY GOING FOR ONLY
SCHOOLCRAFT COUNTY THRU 14Z AND DROPPED ADVISORY FOR MNM-DELTA AND
LUCE WHERE SNOW HAS BEEN VERY LIGHT AND APPEARS TO BE
DIMINISHING.
TODAY AND TONIGHT...THE MAIN SHORTWAVE OF CONCERN FOR THIS FCST PD
IS IMMEDIATELY UPSTREAM OVER THE NRN PLAINS AND WILL BE PUSHING
THROUGH THE UPPER GREAT LAKES LATE THIS MORNING AND AFTERNOON. THE
NEXT INTRUSION OF ARCTIC AIR WILL BE PUSHING INTO THE WESTERN CWA
BEHIND A COLD FRONT AT THE START OF THE PERIOD. MODELS INDICATE 850
MB TEMPS FALLING TO -20 TO -23C BY THE AFTERNOON COMBINED WITH
INVERSION HEIGHTS RISING TO 8-10KFT AND UNIDIRECTIONAL WESTERLY
WINDS RESULTING IN FAVORABLE LOW LEVEL CONV AND THE LIKELYHOOD OF A
DOMINANT LES BAND IMPACTING THE KEWEENAW PENINSULA. WITH THE PASSAGE
OF THE SHRTWV...EXPECT WINDS WOULD VEER FROM WSW TO MORE DUE
W...PUSHING THE DOMINANT BAND SLOWLY TO THE SOUTH FROM NEAR EAGLE
RIVER TO CALUMET/MOHAWK AND TO HOUGHTON THIS AFTERNOON AND TO POINTS
SOUTH OF HOUGHTON THIS EVENING. SNOWFALL ACCUMULATIONS WILL GREATLY
DEPEND ON HOW LONG THE HEAVIER BAND LINGERS IN ANY ONE
LOCATION...ACCUMULATIONS OF 6-10 INCHES REMAIN VERY LIKELY LATE THIS
MORNING THROUGH TONIGHT. IN ADDITION...BLUSTERY WEST WINDS OF
20-30MPH WITH GUSTS OVER 35 MPH WILL PRODUCE CONSIDERABLE BLOWING
AND DRIFTING SNOW AND NEAR WHITEOUT CONDITIONS WHERE THE DOMINANT
BAND SETS UP. HOWEVER...SINCE MOST OF THE 00Z AND 06Z LOCAL AND
REGIONAL HIGHER RES MODELS STILL INDICATE THAT THE DOMINANT BAND
WILL BE GRADUALLY MOVING SOUTH ACROSS THE KEWEENAW PENINSULA FROM
LATE MORNING THROUGH THE AFTERNOON HRS...FELT RELUCTANT TO UPGRADE
TO A WARNING AS AMOUNTS MAY BE SOMEWHAT LIMITED DUE TO TRANSIENT
NATURE OF BAND. I AM ALSO A LITTLE CONCERNED THAT BEST ENHANCEMENT
POTENTIAL FOR DOMINANT LES BAND WILL ARRIVE AHEAD OF THE SHORTWAVE
AND JUST BEFORE WINDS BEGIN TO VEER FROM WSW TO W SO THERE IS A
CHANCE THAT THE DOMINANT BAND MAY BE STRONGEST OUT OVER THE WATER
BEFORE IT REALLY MOVES ONSHORE TO THE KEWEENAW. DUE TO ABOVE
REASONING...DECIDED TO KEEP THE ADVISORY GOING BUT KEPT IN STRONGER
WORDING OF OCCASIONAL HEAVY SNOW AND CONSIDERABLE BLOWING
SNOW/LOCALIZED WHITEOUT CONDITONS IN WSW STATEMENT UNDER THE DOMINANT
BAND...STRESSING DIFFICULT TRAVEL AT TIMES DUE TO POOR VISIBILITY AND
BLOWING/DRIFTING SNOW. SOME OF THE HIGHER RES MODELS PARTICULARLY THE
LOCAL WRF-ARW INDICATE THAT DOMINANT COULD GET PUSHED SOUTH OF
HOUGHTON FOR A TIME THIS EVENING AND PERHAPS EVEN AFFECT NE ONTONAGON
AND NRN BARAGA COUNTIES BEFORE SHIFTING BACK ACROSS THE NRN PORTION
OF KEWEENAW OVERNIGHT AS WINDS BACK WSW AGAIN IN RESPONSE TO SFC RDG
BUILDING IN FM THE WEST.
THE REST OF THE CWA WILL FEEL THE EFFECT OF THE BITTER COLD AIR
FLOODING THE REGION. MAY FLIRT WITH WIND CHILL ADVISORY CRITERIA OF
25 BLO ZERO OR COLDER TONIGHT OVER THE WEST HALF INTERIOR OF THE CWA
AS ACTUAL TEMPS PLUMMET INTO THE DOUBLE DIGITS BLO ZERO.
.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 18Z TAFS THROUGH 18Z TUESDAY AFTERNOON)
ISSUED AT 117 PM EST MON DEC 9 2013
KIWD...EXPECT MVFR CIGS AND -SN IN WSW FLOW THROUGH MUCH OF THIS AFTERNOON.
CONDITIONS SHOULD IMPROVE TO VFR THIS EVENING AS WINDS BACK MORE SW.
MVFR CONDITIONS IN LIGHT SNOW RETURN LATE TONIGHT WITH APPROACH OF
NEXT DISTURBANCE THE NOTRHERN PLAINS.
KCMX...IFR CONDITIONS WILL LOWER TO LIFR/VLIFR VSBY IN MODERATE TO
HEAVY LAKE EFFECT SNOW THIS AFTERNOON AS WSW WINDS VEER TO THE W AND
BECOME GUSTY. THIS WILL CONTINUE INTO THE EVENING HOURS BUT SHOULD
IMPROVE BY LATE EVENING. CONDITIONS WILL IMPROVE AGAIN TO MVFR LATE
TONIGHT AS THE HEAVIER LES BANDS SHIFT NORTH OF THE AREA.
KSAW...MVFR CIGS THIS AFTERNOON ARE EXPECTED THAT WILL LIFT BACK TO
VFR AS A DISTUBANCE MOVES TO THE EAST OF THE AREA. THE NEXT
SHORTWAVE TROUGH MOVING INTO THE AREA TUE MORNING WILL BRING ANOTHER
PERIOD OF MVFR CIGS WITH SOME LIGHT SNOW SHOWERS OR FLURRIES.
&&
.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 551 AM 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 WILL
PASS ACROSS LAKE SUPERIOR LATE THIS MORNING/AFTERNOON VEERING WINDS
TO THE WEST AND INCREASING THEM TO GALES TO 35 TO 40 KNOTS ACROSS
LAKE SUPERIOR 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 10 PM EST /9 PM CST/ THIS EVENING FOR
LSZ241>243-246-247.
GALE WARNING UNTIL MIDNIGHT EST TONIGHT FOR LSZ263.
LAKE MICHIGAN...
GALE WARNING UNTIL 10 PM EST THIS EVENING FOR LMZ221-248-250.
&&
$$
SHORT TERM...VOSS
LONG TERM...SRF
AVIATION...JLB
MARINE...VOSS
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
118 PM EST MON DEC 9 2013
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 551 AM EST MON DEC 9 2013
WV IMAGERY AND RUC ANALYSIS STILL SHOWING A BROAD MID/UPPER LEVEL
TROUGH OVER THE WRN CONUS RESULTING IN WSW FLOW FROM THE PLAINS INTO
THE GREAT LAKES. THERE ARE SEVERAL SHORTWAVES OF NOTE FOR THE SHORT
TERM.
ONE SHORTWAVE MOVING ACROSS LAKE MI INTO LOWER MI AND ITS
ASSOC SFC LOW PRODUCED LIGHT SNOW ACROSS THE CWA LAST NIGHT INTO THE
EARLY MORNING. MOST OF THE AREA RECEIVED GENERALLY NO MORE THAN AN
INCH OF SYSTEM SNOW...ALTHOUGH SOME LOCATIONS ALONG LAKE MI LIKELY
RECEIVED 2 TO LOCALLY 4 INCHES OF SNOW DUE TO LAKE ENHANCEMENT OF
SNOW OFF LAKE MI. MQT RADAR WAS SHOWING A MORE PROMINENT BAND OF
LAKE ENHANCED SNOW FROM NEAR COOKS/MANISTIQUE AREA NORTH TO
SHINGLETON IN THE PAST FEW HOURS ALTHOUGH IT LOOKS LIKE THIS BAND
MAY BE WEAKENING NOW AS BEST FORCING FOR ENHANCEMENT APPEARS TO BE
LIFTING EAST WITH THE SHORTWAVE. DUE TO ISOLATED NATURE OF THIS
BAND DECIDED TO ONLY KEEP WINTER WX ADVISORY GOING FOR ONLY
SCHOOLCRAFT COUNTY THRU 14Z AND DROPPED ADVISORY FOR MNM-DELTA AND
LUCE WHERE SNOW HAS BEEN VERY LIGHT AND APPEARS TO BE
DIMINISHING.
TODAY AND TONIGHT...THE MAIN SHORTWAVE OF CONCERN FOR THIS FCST PD
IS IMMEDIATELY UPSTREAM OVER THE NRN PLAINS AND WILL BE PUSHING
THROUGH THE UPPER GREAT LAKES LATE THIS MORNING AND AFTERNOON. THE
NEXT INTRUSION OF ARCTIC AIR WILL BE PUSHING INTO THE WESTERN CWA
BEHIND A COLD FRONT AT THE START OF THE PERIOD. MODELS INDICATE 850
MB TEMPS FALLING TO -20 TO -23C BY THE AFTERNOON COMBINED WITH
INVERSION HEIGHTS RISING TO 8-10KFT AND UNIDIRECTIONAL WESTERLY
WINDS RESULTING IN FAVORABLE LOW LEVEL CONV AND THE LIKELYHOOD OF A
DOMINANT LES BAND IMPACTING THE KEWEENAW PENINSULA. WITH THE PASSAGE
OF THE SHRTWV...EXPECT WINDS WOULD VEER FROM WSW TO MORE DUE
W...PUSHING THE DOMINANT BAND SLOWLY TO THE SOUTH FROM NEAR EAGLE
RIVER TO CALUMET/MOHAWK AND TO HOUGHTON THIS AFTERNOON AND TO POINTS
SOUTH OF HOUGHTON THIS EVENING. SNOWFALL ACCUMULATIONS WILL GREATLY
DEPEND ON HOW LONG THE HEAVIER BAND LINGERS IN ANY ONE
LOCATION...ACCUMULATIONS OF 6-10 INCHES REMAIN VERY LIKELY LATE THIS
MORNING THROUGH TONIGHT. IN ADDITION...BLUSTERY WEST WINDS OF
20-30MPH WITH GUSTS OVER 35 MPH WILL PRODUCE CONSIDERABLE BLOWING
AND DRIFTING SNOW AND NEAR WHITEOUT CONDITIONS WHERE THE DOMINANT
BAND SETS UP. HOWEVER...SINCE MOST OF THE 00Z AND 06Z LOCAL AND
REGIONAL HIGHER RES MODELS STILL INDICATE THAT THE DOMINANT BAND
WILL BE GRADUALLY MOVING SOUTH ACROSS THE KEWEENAW PENINSULA FROM
LATE MORNING THROUGH THE AFTERNOON HRS...FELT RELUCTANT TO UPGRADE
TO A WARNING AS AMOUNTS MAY BE SOMEWHAT LIMITED DUE TO TRANSIENT
NATURE OF BAND. I AM ALSO A LITTLE CONCERNED THAT BEST ENHANCEMENT
POTENTIAL FOR DOMINANT LES BAND WILL ARRIVE AHEAD OF THE SHORTWAVE
AND JUST BEFORE WINDS BEGIN TO VEER FROM WSW TO W SO THERE IS A
CHANCE THAT THE DOMINANT BAND MAY BE STRONGEST OUT OVER THE WATER
BEFORE IT REALLY MOVES ONSHORE TO THE KEWEENAW. DUE TO ABOVE
REASONING...DECIDED TO KEEP THE ADVISORY GOING BUT KEPT IN STRONGER
WORDING OF OCCASIONAL HEAVY SNOW AND CONSIDERABLE BLOWING
SNOW/LOCALIZED WHITEOUT CONDITONS IN WSW STATEMENT UNDER THE DOMINANT
BAND...STRESSING DIFFICULT TRAVEL AT TIMES DUE TO POOR VISIBILITY AND
BLOWING/DRIFTING SNOW. SOME OF THE HIGHER RES MODELS PARTICULARLY THE
LOCAL WRF-ARW INDICATE THAT DOMINANT COULD GET PUSHED SOUTH OF
HOUGHTON FOR A TIME THIS EVENING AND PERHAPS EVEN AFFECT NE ONTONAGON
AND NRN BARAGA COUNTIES BEFORE SHIFTING BACK ACROSS THE NRN PORTION
OF KEWEENAW OVERNIGHT AS WINDS BACK WSW AGAIN IN RESPONSE TO SFC RDG
BUILDING IN FM THE WEST.
THE REST OF THE CWA WILL FEEL THE EFFECT OF THE BITTER COLD AIR
FLOODING THE REGION. MAY FLIRT WITH WIND CHILL ADVISORY CRITERIA OF
25 BLO ZERO OR COLDER TONIGHT OVER THE WEST HALF INTERIOR OF THE CWA
AS ACTUAL TEMPS PLUMMET INTO THE DOUBLE DIGITS BLO ZERO.
.LONG TERM...(TUESDAY THROUGH SUNDAY)
ISSUED AT 519 AM EST MON DEC 9 2013
CONTINUED NW FLOW ALOFT THROUGH THE WEEK WILL BRING LAKE EFFECT SNOW
FOR W TO NW FAVORED SNOW BELTS OFF AND ON. FOR THE REST OF UPPER
MI...ONLY BRIEF ROUNDS OF LIGHT SYNOPTIC SNOWFALL ARE EXPECTED.
ARCTIC AIR WILL REMAIN ANCHORED ACROSS THE REGION WITH MULTIPLE
REINFORCING SHOTS THROUGH THIS WEEKEND.
TUESDAY...DEEP TROUGHING OVER EASTERN NORTH AMERICA WILL CONTINUE TO
SEND MULTIPLE WEAK TROUGHS THROUGH THE GREAT LAKES REGION. THE FIRST
OF THESE IS PROGGED TO IMPACT THE CWA AT THE BEGINNING OF THE
FORECAST PERIOD. MODEL AGREEMENT HAS BEEN DECENT OVER THE PAST
COUPLE OF DAYS...SO OVERALL CONFIDENCE IS GOOD. THE WEAK SHORTWAVE
TROUGH WILL TRACK EASTWARD ACROSS NORTHERN WI THROUGHOUT THE DAY
TUESDAY. BESIDE MID-LEVEL Q-VECTOR CONV WITH THE TROUGH...THERE WILL
BE LITTLE SYNOPTIC SUPPORT. THOUGH A SECONDARY SFC LOW FORMING OVER
NORTHERN LAKE MI TUESDAY AFTERNOON IN RESPONSE THE TO MID-LEVEL
TROUGH/WARMER LAKE TEMPS COULD BACK SFC WINDS TO THE SW AND BRING
SOME MINOR LAKE ENHANCEMENT TO THE FAR SE CWA...MINIMAL ADDITIONAL
ACCUMULATION IS EXPECTED. OVERALL...CANNOT FIND ANYTHING TO JUSTIFY
THIS BEING MORE THAN A DUSTING OF SNOW FOR MOST AREAS.
EXPECTED WNW LES WILL BE SLOW TO GET GOING TUESDAY AFTERNOON UNTIL
THE MAIN SFC-H8 TROUGHS PASS EARLY TUESDAY EVENING. A BRIEF BOUT OF
SNOW ALONG THESE TROUGHS WILL BE POSSIBLE...SO BROUGHT HIGHER POPS
INLAND ACROSS THE NORTHERN CWA A BIT MORE THAN PREVIOUS FORECAST.
TUESDAY NIGHT THROUGH WEDNESDAY NIGHT...BUMPED UP CLOUD COVER
TUESDAY NIGHT WITH LINGERING LOW-LEVEL MOISTURE AND NO REAL MEANS TO
GET RID OF IT. THIS IMPACTS LOW TEMPS...SO HAVE INCREASED THOSE A
DEGREE OR TWO. CLOUD COVER MAY CREATE SOME DISPARITY IN MIN TEMPS
ACROSS THE CWA...SO WOULD NOT BE SURPRISED IF ONLY PORTIONS OF THE
WEST HALF REACH THEIR FORECAST MIN TEMPS TO -10F.
LES PICKS UP IN INTENSITY WITH COLDER AIR CONTINUING TO ADVECT INTO
THE AREA. MODEL GUIDANCE IS PICKING UP ON CONSIDERABLE SFC
CONVERGENCE ALONG THE EASTERN SHORELINE AS THE DEPARTING SFC TROUGH
HOLDS ON OVER WARMER LAKE WATERS. COULD SEE AN IMPRESSIVE LES BAND
IN FAR NORTHERN LUCE TO NORTHERN CHIPPEWA COUNTIES. LOCATIONS VERY
NEAR LAKE SUPERIOR EAST OF GRAND MARAIS COULD SEE IN EXCESS OF 8
INCHES...WITH SOME LOCATIONS CLOSER TO WHITEFISH POINT POSSIBLY
SURPASSING A FOOT...TUESDAY NIGHT INTO WEDNESDAY MORNING. A LOT HAS
TO BE IRONED OUT WITH BAND PLACEMENT...SO DID NOT ISSUE AN LES WATCH
ATTM.
A WEAK AND BROAD TROUGH AXIS CROSSING THE AREA WEDNESDAY WILL ONLY
ENHANCE SOME LOW-LEVEL CLOUDINESS AND ASSIST IN KEEPING TEMPS EVEN
COLDER FOR THE DAY. WITH H8 TEMPS AT -25C AND CONTINUOUS CAA
THROUGHOUT THE DAY...INTERIOR WEST LOCATIONS...ESPECIALLY ALONG THE
WI BORDER...MAY FAIL TO GET ABOVE ZERO IN THE AFTERNOON. THE SFC
WIND FIELD BECOMES A BIT MUDDLED WEDNESDAY NIGHT AS A WEAK SFC LOW
TRACKS SE ACROSS IA...BUT A WEAK SFC RIDGE SHOULD KEEP WINDS LIGHT
AND ALLOW TEMPS TO PLUMMET ACROSS THE CWA. DID BUMP TEMPS BACK UP A
COUPLE DEGREES THOUGH AS MID-LEVEL CLOUDINESS MAY BE ON THE RISE
LATE IN THE NIGHT WITH THE APPROACH OF AN UPPER JET AND SUBTLE
MID-LEVEL TROUGH. WITH THAT SAID...SOME OF THE COLDEST LOCATIONS
ACROSS THE CENTRAL CWA COULD SEE TEMPS FALL AS LOW AS -20F. THOUGH
WINDS WILL BE LIGHT...WIND CHILLS WILL STILL DROP AS LOW AS -35F FOR
THE COLDEST LOCATIONS.
THURSDAY THROUGH SUNDAY...DID NOT FOCUS HEAVILY ON THIS PERIOD GIVEN
SOME MODEL DISAGREEMENT. USED THE ECMWF HEAVILY AS THE GFS HAS
DEVELOPED SOME CONTINUITY ISSUES OVER THE PAST FEW RUNS. OVERALL
PATTERN BEGINS TO CHANGE SOMEWHAT...THOUGH TEMPS WILL REMAIN WELL
BELOW NORMAL. A WEAK CLIPPER SYSTEM LOOKS TO BRING ANOTHER ROUND OF
VERY LIGHT SNOW THURSDAY...BUT ONCE AGAIN...OVERALL SUPPORT IS
MINIMAL. AN ASSOCIATED SFC TROUGH WILL LAY OUT ACROSS THE UPPER MS
VALLEY THROUGH FRIDAY. COMBINED WITH THE RIGHT ENTRANCE OF THE
PASSING UPPER JET...SOME MINOR SYNOPTIC SNOW IS POSSIBLE
FRIDAY...BUT DID NOT PLACE MORE THAN SLIGHT CHANCE POPS AWAY FROM
LAKE SUPERIOR. PLENTY OF CLOUD COVERED AND CONTINUED LES FOR NW SNOW
BELTS SHOULD LAST INTO SATURDAY...BUT MUCH LOWER INVERSION HEIGHTS
WILL LIKELY PREVENT ANY SIGNIFICANT ACCUMULATIONS. WHAT WAS STARTING
TO LOOK LIKE A WARMING TREND THROUGH THE WEEKEND MAY BE HALTED BY
YET ANOTHER CLIPPER SYSTEM TRACKING SE ACROSS THE AREA ON SUNDAY.
COLDER AIR WILL WRAP AROUND THIS AND KEEP TEMPS DOWN INTO EARLY NEXT
WEEK.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z TUESDAY AFTERNOON)
ISSUED AT 117 PM EST MON DEC 9 2013
KIWD...EXPECT MVFR CIGS AND -SN IN WSW FLOW THROUGH MUCH OF THIS AFTERNOON.
CONDITIONS SHOULD IMPROVE TO VFR THIS EVENING AS WINDS BACK MORE SW.
MVFR CONDITIONS IN LIGHT SNOW RETURN LATE TONIGHT WITH APPROACH OF
NEXT DISTURBANCE THE NOTRHERN PLAINS.
KCMX...IFR CONDITIONS WILL LOWER TO LIFR/VLIFR VSBY IN MODERATE TO
HEAVY LAKE EFFECT SNOW THIS AFTERNOON AS WSW WINDS VEER TO THE W AND
BECOME GUSTY. THIS WILL CONTINUE INTO THE EVENING HOURS BUT SHOULD
IMPROVE BY LATE EVENING. CONDITIONS WILL IMPROVE AGAIN TO MVFR LATE
TONIGHT AS THE HEAVIER LES BANDS SHIFT NORTH OF THE AREA.
KSAW...MVFR CIGS THIS AFTERNOON ARE EXPECTED THAT WILL LIFT BACK TO
VFR AS A DISTUBANCE MOVES TO THE EAST OF THE AREA. THE NEXT
SHORTWAVE TROUGH MOVING INTO THE AREA TUE MORNING WILL BRING ANOTHER
PERIOD OF MVFR CIGS WITH SOME LIGHT SNOW SHOWERS OR FLURRIES.
&&
.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 551 AM EST MON DEC 9 2013(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 400 PM EST SUN DEC 8 2013
A SERIES OF TROUGHS WILL CROSS LAKE SUPERIOR THROUGH THE UPCOMING
WEEK AND BRING MULTIPLE CHANCES FOR GALES. THE FIRST TROUGH WILL
PASS ACROSS LAKE SUPERIOR LATE THIS MORNING/AFTERNOON VEERING WINDS
TO THE WEST AND INCREASING THEM TO GALES TO 35 TO 40 KNOTS ACROSS
LAKE SUPERIOR 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 SUPERIOR...
HEAVY FREEZING SPRAY WARNING FROM 7 PM THIS EVENING TO 7 AM EST
TUESDAY FOR LSZ245-248>251-265>267.
GALE WARNING UNTIL 5 AM EST TUESDAY FOR LSZ244-245-265>267.
HEAVY FREEZING SPRAY WARNING UNTIL 7 AM EST /6 AM CST/ TUESDAY
FOR LSZ162-240>244-263-264.
GALE WARNING UNTIL 5 AM EST TUESDAY FOR LSZ264.
GALE WARNING UNTIL 10 PM EST /9 PM CST/ THIS EVENING FOR
LSZ241>243-246-247.
GALE WARNING UNTIL MIDNIGHT EST TONIGHT FOR LSZ263.
LAKE MICHIGAN...
GALE WARNING UNTIL 10 PM EST THIS EVENING FOR LMZ221-248-250.
&&
$$
SHORT TERM...VOSS
LONG TERM...KLUBER
AVIATION...JLB
MARINE...VOSS
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
749 AM EST MON DEC 9 2013
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 551 AM EST MON DEC 9 2013
WV IMAGERY AND RUC ANALYSIS STILL SHOWING A BROAD MID/UPPER LEVEL
TROUGH OVER THE WRN CONUS RESULTING IN WSW FLOW FROM THE PLAINS INTO
THE GREAT LAKES. THERE ARE SEVERAL SHORTWAVES OF NOTE FOR THE SHORT
TERM.
ONE SHORTWAVE MOVING ACROSS LAKE MI INTO LOWER MI AND ITS
ASSOC SFC LOW PRODUCED LIGHT SNOW ACROSS THE CWA LAST NIGHT INTO THE
EARLY MORNING. MOST OF THE AREA RECEIVED GENERALLY NO MORE THAN AN
INCH OF SYSTEM SNOW...ALTHOUGH SOME LOCATIONS ALONG LAKE MI LIKELY
RECEIVED 2 TO LOCALLY 4 INCHES OF SNOW DUE TO LAKE ENHANCEMENT OF
SNOW OFF LAKE MI. MQT RADAR WAS SHOWING A MORE PROMINENT BAND OF
LAKE ENHANCED SNOW FROM NEAR COOKS/MANISTIQUE AREA NORTH TO
SHINGLETON IN THE PAST FEW HOURS ALTHOUGH IT LOOKS LIKE THIS BAND
MAY BE WEAKENING NOW AS BEST FORCING FOR ENHANCEMENT APPEARS TO BE
LIFTING EAST WITH THE SHORTWAVE. DUE TO ISOLATED NATURE OF THIS
BAND DECIDED TO ONLY KEEP WINTER WX ADVISORY GOING FOR ONLY
SCHOOLCRAFT COUNTY THRU 14Z AND DROPPED ADVISORY FOR MNM-DELTA AND
LUCE WHERE SNOW HAS BEEN VERY LIGHT AND APPEARS TO BE
DIMINISHING.
TODAY AND TONIGHT...THE MAIN SHORTWAVE OF CONCERN FOR THIS FCST PD
IS IMMEDIATELY UPSTREAM OVER THE NRN PLAINS AND WILL BE PUSHING
THROUGH THE UPPER GREAT LAKES LATE THIS MORNING AND AFTERNOON. THE
NEXT INTRUSION OF ARCTIC AIR WILL BE PUSHING INTO THE WESTERN CWA
BEHIND A COLD FRONT AT THE START OF THE PERIOD. MODELS INDICATE 850
MB TEMPS FALLING TO -20 TO -23C BY THE AFTERNOON COMBINED WITH
INVERSION HEIGHTS RISING TO 8-10KFT AND UNIDIRECTIONAL WESTERLY
WINDS RESULTING IN FAVORABLE LOW LEVEL CONV AND THE LIKELYHOOD OF A
DOMINANT LES BAND IMPACTING THE KEWEENAW PENINSULA. WITH THE PASSAGE
OF THE SHRTWV...EXPECT WINDS WOULD VEER FROM WSW TO MORE DUE
W...PUSHING THE DOMINANT BAND SLOWLY TO THE SOUTH FROM NEAR EAGLE
RIVER TO CALUMET/MOHAWK AND TO HOUGHTON THIS AFTERNOON AND TO POINTS
SOUTH OF HOUGHTON THIS EVENING. SNOWFALL ACCUMULATIONS WILL GREATLY
DEPEND ON HOW LONG THE HEAVIER BAND LINGERS IN ANY ONE
LOCATION...ACCUMULATIONS OF 6-10 INCHES REMAIN VERY LIKELY LATE THIS
MORNING THROUGH TONIGHT. IN ADDITION...BLUSTERY WEST WINDS OF
20-30MPH WITH GUSTS OVER 35 MPH WILL PRODUCE CONSIDERABLE BLOWING
AND DRIFTING SNOW AND NEAR WHITEOUT CONDITIONS WHERE THE DOMINANT
BAND SETS UP. HOWEVER...SINCE MOST OF THE 00Z AND 06Z LOCAL AND
REGIONAL HIGHER RES MODELS STILL INDICATE THAT THE DOMINANT BAND
WILL BE GRADUALLY MOVING SOUTH ACROSS THE KEWEENAW PENINSULA FROM
LATE MORNING THROUGH THE AFTERNOON HRS...FELT RELUCTANT TO UPGRADE
TO A WARNING AS AMOUNTS MAY BE SOMEWHAT LIMITED DUE TO TRANSIENT
NATURE OF BAND. I AM ALSO A LITTLE CONCERNED THAT BEST ENHANCEMENT
POTENTIAL FOR DOMINANT LES BAND WILL ARRIVE AHEAD OF THE SHORTWAVE
AND JUST BEFORE WINDS BEGIN TO VEER FROM WSW TO W SO THERE IS A
CHANCE THAT THE DOMINANT BAND MAY BE STRONGEST OUT OVER THE WATER
BEFORE IT REALLY MOVES ONSHORE TO THE KEWEENAW. DUE TO ABOVE
REASONING...DECIDED TO KEEP THE ADVISORY GOING BUT KEPT IN STRONGER
WORDING OF OCCASIONAL HEAVY SNOW AND CONSIDERABLE BLOWING
SNOW/LOCALIZED WHITEOUT CONDITONS IN WSW STATEMENT UNDER THE DOMINANT
BAND...STRESSING DIFFICULT TRAVEL AT TIMES DUE TO POOR VISIBILITY AND
BLOWING/DRIFTING SNOW. SOME OF THE HIGHER RES MODELS PARTICULARLY THE
LOCAL WRF-ARW INDICATE THAT DOMINANT COULD GET PUSHED SOUTH OF
HOUGHTON FOR A TIME THIS EVENING AND PERHAPS EVEN AFFECT NE ONTONAGON
AND NRN BARAGA COUNTIES BEFORE SHIFTING BACK ACROSS THE NRN PORTION
OF KEWEENAW OVERNIGHT AS WINDS BACK WSW AGAIN IN RESPONSE TO SFC RDG
BUILDING IN FM THE WEST.
THE REST OF THE CWA WILL FEEL THE EFFECT OF THE BITTER COLD AIR
FLOODING THE REGION. MAY FLIRT WITH WIND CHILL ADVISORY CRITERIA OF
25 BLO ZERO OR COLDER TONIGHT OVER THE WEST HALF INTERIOR OF THE CWA
AS ACTUAL TEMPS PLUMMET INTO THE DOUBLE DIGITS BLO ZERO.
.LONG TERM...(TUESDAY THROUGH SUNDAY)
ISSUED AT 519 AM EST MON DEC 9 2013
CONTINUED NW FLOW ALOFT THROUGH THE WEEK WILL BRING LAKE EFFECT SNOW
FOR W TO NW FAVORED SNOW BELTS OFF AND ON. FOR THE REST OF UPPER
MI...ONLY BRIEF ROUNDS OF LIGHT SYNOPTIC SNOWFALL ARE EXPECTED.
ARCTIC AIR WILL REMAIN ANCHORED ACROSS THE REGION WITH MULTIPLE
REINFORCING SHOTS THROUGH THIS WEEKEND.
TUESDAY...DEEP TROUGHING OVER EASTERN NORTH AMERICA WILL CONTINUE TO
SEND MULTIPLE WEAK TROUGHS THROUGH THE GREAT LAKES REGION. THE FIRST
OF THESE IS PROGGED TO IMPACT THE CWA AT THE BEGINNING OF THE
FORECAST PERIOD. MODEL AGREEMENT HAS BEEN DECENT OVER THE PAST
COUPLE OF DAYS...SO OVERALL CONFIDENCE IS GOOD. THE WEAK SHORTWAVE
TROUGH WILL TRACK EASTWARD ACROSS NORTHERN WI THROUGHOUT THE DAY
TUESDAY. BESIDE MID-LEVEL Q-VECTOR CONV WITH THE TROUGH...THERE WILL
BE LITTLE SYNOPTIC SUPPORT. THOUGH A SECONDARY SFC LOW FORMING OVER
NORTHERN LAKE MI TUESDAY AFTERNOON IN RESPONSE THE TO MID-LEVEL
TROUGH/WARMER LAKE TEMPS COULD BACK SFC WINDS TO THE SW AND BRING
SOME MINOR LAKE ENHANCEMENT TO THE FAR SE CWA...MINIMAL ADDITIONAL
ACCUMULATION IS EXPECTED. OVERALL...CANNOT FIND ANYTHING TO JUSTIFY
THIS BEING MORE THAN A DUSTING OF SNOW FOR MOST AREAS.
EXPECTED WNW LES WILL BE SLOW TO GET GOING TUESDAY AFTERNOON UNTIL
THE MAIN SFC-H8 TROUGHS PASS EARLY TUESDAY EVENING. A BRIEF BOUT OF
SNOW ALONG THESE TROUGHS WILL BE POSSIBLE...SO BROUGHT HIGHER POPS
INLAND ACROSS THE NORTHERN CWA A BIT MORE THAN PREVIOUS FORECAST.
TUESDAY NIGHT THROUGH WEDNESDAY NIGHT...BUMPED UP CLOUD COVER
TUESDAY NIGHT WITH LINGERING LOW-LEVEL MOISTURE AND NO REAL MEANS TO
GET RID OF IT. THIS IMPACTS LOW TEMPS...SO HAVE INCREASED THOSE A
DEGREE OR TWO. CLOUD COVER MAY CREATE SOME DISPARITY IN MIN TEMPS
ACROSS THE CWA...SO WOULD NOT BE SURPRISED IF ONLY PORTIONS OF THE
WEST HALF REACH THEIR FORECAST MIN TEMPS TO -10F.
LES PICKS UP IN INTENSITY WITH COLDER AIR CONTINUING TO ADVECT INTO
THE AREA. MODEL GUIDANCE IS PICKING UP ON CONSIDERABLE SFC
CONVERGENCE ALONG THE EASTERN SHORELINE AS THE DEPARTING SFC TROUGH
HOLDS ON OVER WARMER LAKE WATERS. COULD SEE AN IMPRESSIVE LES BAND
IN FAR NORTHERN LUCE TO NORTHERN CHIPPEWA COUNTIES. LOCATIONS VERY
NEAR LAKE SUPERIOR EAST OF GRAND MARAIS COULD SEE IN EXCESS OF 8
INCHES...WITH SOME LOCATIONS CLOSER TO WHITEFISH POINT POSSIBLY
SURPASSING A FOOT...TUESDAY NIGHT INTO WEDNESDAY MORNING. A LOT HAS
TO BE IRONED OUT WITH BAND PLACEMENT...SO DID NOT ISSUE AN LES WATCH
ATTM.
A WEAK AND BROAD TROUGH AXIS CROSSING THE AREA WEDNESDAY WILL ONLY
ENHANCE SOME LOW-LEVEL CLOUDINESS AND ASSIST IN KEEPING TEMPS EVEN
COLDER FOR THE DAY. WITH H8 TEMPS AT -25C AND CONTINUOUS CAA
THROUGHOUT THE DAY...INTERIOR WEST LOCATIONS...ESPECIALLY ALONG THE
WI BORDER...MAY FAIL TO GET ABOVE ZERO IN THE AFTERNOON. THE SFC
WIND FIELD BECOMES A BIT MUDDLED WEDNESDAY NIGHT AS A WEAK SFC LOW
TRACKS SE ACROSS IA...BUT A WEAK SFC RIDGE SHOULD KEEP WINDS LIGHT
AND ALLOW TEMPS TO PLUMMET ACROSS THE CWA. DID BUMP TEMPS BACK UP A
COUPLE DEGREES THOUGH AS MID-LEVEL CLOUDINESS MAY BE ON THE RISE
LATE IN THE NIGHT WITH THE APPROACH OF AN UPPER JET AND SUBTLE
MID-LEVEL TROUGH. WITH THAT SAID...SOME OF THE COLDEST LOCATIONS
ACROSS THE CENTRAL CWA COULD SEE TEMPS FALL AS LOW AS -20F. THOUGH
WINDS WILL BE LIGHT...WIND CHILLS WILL STILL DROP AS LOW AS -35F FOR
THE COLDEST LOCATIONS.
THURSDAY THROUGH SUNDAY...DID NOT FOCUS HEAVILY ON THIS PERIOD GIVEN
SOME MODEL DISAGREEMENT. USED THE ECMWF HEAVILY AS THE GFS HAS
DEVELOPED SOME CONTINUITY ISSUES OVER THE PAST FEW RUNS. OVERALL
PATTERN BEGINS TO CHANGE SOMEWHAT...THOUGH TEMPS WILL REMAIN WELL
BELOW NORMAL. A WEAK CLIPPER SYSTEM LOOKS TO BRING ANOTHER ROUND OF
VERY LIGHT SNOW THURSDAY...BUT ONCE AGAIN...OVERALL SUPPORT IS
MINIMAL. AN ASSOCIATED SFC TROUGH WILL LAY OUT ACROSS THE UPPER MS
VALLEY THROUGH FRIDAY. COMBINED WITH THE RIGHT ENTRANCE OF THE
PASSING UPPER JET...SOME MINOR SYNOPTIC SNOW IS POSSIBLE
FRIDAY...BUT DID NOT PLACE MORE THAN SLIGHT CHANCE POPS AWAY FROM
LAKE SUPERIOR. PLENTY OF CLOUD COVERED AND CONTINUED LES FOR NW SNOW
BELTS SHOULD LAST INTO SATURDAY...BUT MUCH LOWER INVERSION HEIGHTS
WILL LIKELY PREVENT ANY SIGNIFICANT ACCUMULATIONS. WHAT WAS STARTING
TO LOOK LIKE A WARMING TREND THROUGH THE WEEKEND MAY BE HALTED BY
YET ANOTHER CLIPPER SYSTEM TRACKING SE ACROSS THE AREA ON SUNDAY.
COLDER AIR WILL WRAP AROUND THIS AND KEEP TEMPS DOWN INTO EARLY NEXT
WEEK.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z TUESDAY MORNING)
ISSUED AT 738 AM EST MON DEC 9 2013
KIWD...EXPECT MVFR CIGS AND -SN IN WSW FLOW THROUGH MUCH OF THE DAY.
CONDITIONS SHOULD IMPROVE TO VFR THIS EVENING AS WINDS BACK MORE SW.
MVFR CONDITIONS IN LIGHT SNOW RETURN LATE TONIGHT WITH APPROACH OF
NEXT SYSTEM FROM THE NOTRHERN PLAINS.
KCMX...MVFR CONDITIONS WILL LOWER TO LIFR/VLIFR VSBY IN MODERATE TO
HEAVY LAKE EFFECT SNOW BY MID MORNING AS WINDS VEER TO THE WEST AND
BECOME GUSTY AND THIS WILL CONTINUE INTO THE EVENING HRS. CONDITIONS
WILL IMPROVE AGAIN TO MVFR LATE TONIGHT AS LES BAND SHIFT OF THE
AREA.
KSAW...EXPECT VFR CONDITIONS THROUGH MUCH OF THE PD IN W-SW FLOW. WSW
WINDS WILL LIKELY GUST OVER 20KT FOR A PERIOD THIS AFTERNOON.
&&
.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 551 AM EST MON DEC 9 2013(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 400 PM EST SUN DEC 8 2013
A SERIES OF TROUGHS WILL CROSS LAKE SUPERIOR THROUGH THE UPCOMING
WEEK AND BRING MULTIPLE CHANCES FOR GALES. THE FIRST TROUGH WILL
PASS ACROSS LAKE SUPERIOR LATE THIS MORNING/AFTERNOON VEERING WINDS
TO THE WEST AND INCREASING THEM TO GALES TO 35 TO 40 KNOTS ACROSS
LAKE SUPERIOR 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...
WINTER WEATHER ADVISORY UNTIL 9 AM EST THIS MORNING FOR MIZ014-
085.
LAKE EFFECT SNOW ADVISORY UNTIL 7 AM EST TUESDAY FOR MIZ001-003.
LAKE SUPERIOR...
HEAVY FREEZING SPRAY WARNING FROM 7 PM THIS EVENING TO 7 AM EST
TUESDAY FOR LSZ245-248>251-265>267.
GALE WARNING FROM 1 PM THIS AFTERNOON TO 5 AM EST TUESDAY FOR
LSZ244-245-265>267.
HEAVY FREEZING SPRAY WARNING FROM 1 PM EST /NOON CST/ THIS
AFTERNOON TO 7 AM EST /6 AM CST/ TUESDAY FOR LSZ162-240>244-
263-264.
GALE WARNING FROM 4 PM THIS AFTERNOON TO 5 AM EST TUESDAY FOR
LSZ264.
GALE WARNING FROM 1 PM EST /NOON CST/ THIS AFTERNOON TO 10 PM
EST /9 PM CST/ THIS EVENING FOR LSZ241>243-246-247.
GALE WARNING FROM 1 PM THIS AFTERNOON TO MIDNIGHT EST TONIGHT
FOR LSZ263.
LAKE MICHIGAN...
GALE WARNING FROM 4 PM THIS AFTERNOON TO 10 PM EST THIS EVENING
FOR LMZ221-248-250.
&&
$$
SHORT TERM...VOSS
LONG TERM...KLUBER
AVIATION...VOSS
MARINE...VOSS
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
552 AM EST MON DEC 9 2013
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 551 AM EST MON DEC 9 2013
WV IMAGERY AND RUC ANALYSIS STILL SHOWING A BROAD MID/UPPER LEVEL
TROUGH OVER THE WRN CONUS RESULTING IN WSW FLOW FROM THE PLAINS INTO
THE GREAT LAKES. THERE ARE SEVERAL SHORTWAVES OF NOTE FOR THE SHORT
TERM.
ONE SHORTWAVE MOVING ACROSS LAKE MI INTO LOWER MI AND ITS
ASSOC SFC LOW PRODUCED LIGHT SNOW ACROSS THE CWA LAST NIGHT INTO THE
EARLY MORNING. MOST OF THE AREA RECEIVED GENERALLY NO MORE THAN AN
INCH OF SYSTEM SNOW...ALTHOUGH SOME LOCATIONS ALONG LAKE MI LIKELY
RECEIVED 2 TO LOCALLY 4 INCHES OF SNOW DUE TO LAKE ENHANCEMENT OF
SNOW OFF LAKE MI. MQT RADAR WAS SHOWING A MORE PROMINENT BAND OF
LAKE ENHANCED SNOW FROM NEAR COOKS/MANISTIQUE AREA NORTH TO
SHINGLETON IN THE PAST FEW HOURS ALTHOUGH IT LOOKS LIKE THIS BAND
MAY BE WEAKENING NOW AS BEST FORCING FOR ENHANCEMENT APPEARS TO BE
LIFTING EAST WITH THE SHORTWAVE. DUE TO ISOLATED NATURE OF THIS
BAND DECIDED TO ONLY KEEP WINTER WX ADVISORY GOING FOR ONLY
SCHOOLCRAFT COUNTY THRU 14Z AND DROPPED ADVISORY FOR MNM-DELTA AND
LUCE WHERE SNOW HAS BEEN VERY LIGHT AND APPEARS TO BE
DIMINISHING.
TODAY AND TONIGHT...THE MAIN SHORTWAVE OF CONCERN FOR THIS FCST PD
IS IMMEDIATELY UPSTREAM OVER THE NRN PLAINS AND WILL BE PUSHING
THROUGH THE UPPER GREAT LAKES LATE THIS MORNING AND AFTERNOON. THE
NEXT INTRUSION OF ARCTIC AIR WILL BE PUSHING INTO THE WESTERN CWA
BEHIND A COLD FRONT AT THE START OF THE PERIOD. MODELS INDICATE 850
MB TEMPS FALLING TO -20 TO -23C BY THE AFTERNOON COMBINED WITH
INVERSION HEIGHTS RISING TO 8-10KFT AND UNIDIRECTIONAL WESTERLY
WINDS RESULTING IN FAVORABLE LOW LEVEL CONV AND THE LIKELYHOOD OF A
DOMINANT LES BAND IMPACTING THE KEWEENAW PENINSULA. WITH THE PASSAGE
OF THE SHRTWV...EXPECT WINDS WOULD VEER FROM WSW TO MORE DUE
W...PUSHING THE DOMINANT BAND SLOWLY TO THE SOUTH FROM NEAR EAGLE
RIVER TO CALUMET/MOHAWK AND TO HOUGHTON THIS AFTERNOON AND TO POINTS
SOUTH OF HOUGHTON THIS EVENING. SNOWFALL ACCUMULATIONS WILL GREATLY
DEPEND ON HOW LONG THE HEAVIER BAND LINGERS IN ANY ONE
LOCATION...ACCUMULATIONS OF 6-10 INCHES REMAIN VERY LIKELY LATE THIS
MORNING THROUGH TONIGHT. IN ADDITION...BLUSTERY WEST WINDS OF
20-30MPH WITH GUSTS OVER 35 MPH WILL PRODUCE CONSIDERABLE BLOWING
AND DRIFTING SNOW AND NEAR WHITEOUT CONDITIONS WHERE THE DOMINANT
BAND SETS UP. HOWEVER...SINCE MOST OF THE 00Z AND 06Z LOCAL AND
REGIONAL HIGHER RES MODELS STILL INDICATE THAT THE DOMINANT BAND
WILL BE GRADUALLY MOVING SOUTH ACROSS THE KEWEENAW PENINSULA FROM
LATE MORNING THROUGH THE AFTERNOON HRS...FELT RELUCTANT TO UPGRADE
TO A WARNING AS AMOUNTS MAY BE SOMEWHAT LIMITED DUE TO TRANSIENT
NATURE OF BAND. I AM ALSO A LITTLE CONCERNED THAT BEST ENHANCEMENT
POTENTIAL FOR DOMINANT LES BAND WILL ARRIVE AHEAD OF THE SHORTWAVE
AND JUST BEFORE WINDS BEGIN TO VEER FROM WSW TO W SO THERE IS A
CHANCE THAT THE DOMINANT BAND MAY BE STRONGEST OUT OVER THE WATER
BEFORE IT REALLY MOVES ONSHORE TO THE KEWEENAW. DUE TO ABOVE
REASONING...DECIDED TO KEEP THE ADVISORY GOING BUT KEPT IN STRONGER
WORDING OF OCCASIONAL HEAVY SNOW AND CONSIDERABLE BLOWING
SNOW/LOCALIZED WHITEOUT CONDITONS UNDER THE DOMINANT
BAND...STRESSING DIFFICULT TRAVEL AT TIMES DUE TO POOR VISIBILITY AND
BLOWING/DRIFTING SNOW. SOME OF THE HIGHER RES MODELS PARTICULARLY
THE LOCAL WRF-ARW INDICATE THAT DOMINANT COULD GET PUSHED SOUTH OF
HOUGHTON FOR A TIME THIS EVENING AND PERHAPS EVEN AFFECT NE
ONTONAGON AND NRN BARAGA COUNTIES BEFORE SHIFTING BACK ACROSS THE
NRN PORTION OF KEWEENAW OVERNIGHT AS WINDS BACK WSW AGAIN IN
RESPONSE TO SFC RDG BUILDING IN FM THE WEST.
THE REST OF THE CWA WILL FEEL THE EFFECT OF THE BITTER COLD AIR
FLOODING THE REGION. MAY FLIRT WITH WIND CHILL ADVISORY CRITERIA OF
25 BLO ZERO OR COLDER TONIGHT OVER THE WEST HALF INTERIOR OF THE CWA
AS ACTUAL TEMPS PLUMMET INTO THE DOUBLE DIGITS BLO ZERO.
.LONG TERM...(TUESDAY THROUGH SUNDAY)
ISSUED AT 519 AM EST MON DEC 9 2013
CONTINUED NW FLOW ALOFT THROUGH THE WEEK WILL BRING LAKE EFFECT SNOW
FOR W TO NW FAVORED SNOW BELTS OFF AND ON. FOR THE REST OF UPPER
MI...ONLY BRIEF ROUNDS OF LIGHT SYNOPTIC SNOWFALL ARE EXPECTED.
ARCTIC AIR WILL REMAIN ANCHORED ACROSS THE REGION WITH MULTIPLE
REINFORCING SHOTS THROUGH THIS WEEKEND.
TUESDAY...DEEP TROUGHING OVER EASTERN NORTH AMERICA WILL CONTINUE TO
SEND MULTIPLE WEAK TROUGHS THROUGH THE GREAT LAKES REGION. THE FIRST
OF THESE IS PROGGED TO IMPACT THE CWA AT THE BEGINNING OF THE
FORECAST PERIOD. MODEL AGREEMENT HAS BEEN DECENT OVER THE PAST
COUPLE OF DAYS...SO OVERALL CONFIDENCE IS GOOD. THE WEAK SHORTWAVE
TROUGH WILL TRACK EASTWARD ACROSS NORTHERN WI THROUGHOUT THE DAY
TUESDAY. BESIDE MID-LEVEL Q-VECTOR CONV WITH THE TROUGH...THERE WILL
BE LITTLE SYNOPTIC SUPPORT. THOUGH A SECONDARY SFC LOW FORMING OVER
NORTHERN LAKE MI TUESDAY AFTERNOON IN RESPONSE THE TO MID-LEVEL
TROUGH/WARMER LAKE TEMPS COULD BACK SFC WINDS TO THE SW AND BRING
SOME MINOR LAKE ENHANCEMENT TO THE FAR SE CWA...MINIMAL ADDITIONAL
ACCUMULATION IS EXPECTED. OVERALL...CANNOT FIND ANYTHING TO JUSTIFY
THIS BEING MORE THAN A DUSTING OF SNOW FOR MOST AREAS.
EXPECTED WNW LES WILL BE SLOW TO GET GOING TUESDAY AFTERNOON UNTIL
THE MAIN SFC-H8 TROUGHS PASS EARLY TUESDAY EVENING. A BRIEF BOUT OF
SNOW ALONG THESE TROUGHS WILL BE POSSIBLE...SO BROUGHT HIGHER POPS
INLAND ACROSS THE NORTHERN CWA A BIT MORE THAN PREVIOUS FORECAST.
TUESDAY NIGHT THROUGH WEDNESDAY NIGHT...BUMPED UP CLOUD COVER
TUESDAY NIGHT WITH LINGERING LOW-LEVEL MOISTURE AND NO REAL MEANS TO
GET RID OF IT. THIS IMPACTS LOW TEMPS...SO HAVE INCREASED THOSE A
DEGREE OR TWO. CLOUD COVER MAY CREATE SOME DISPARITY IN MIN TEMPS
ACROSS THE CWA...SO WOULD NOT BE SURPRISED IF ONLY PORTIONS OF THE
WEST HALF REACH THEIR FORECAST MIN TEMPS TO -10F.
LES PICKS UP IN INTENSITY WITH COLDER AIR CONTINUING TO ADVECT INTO
THE AREA. MODEL GUIDANCE IS PICKING UP ON CONSIDERABLE SFC
CONVERGENCE ALONG THE EASTERN SHORELINE AS THE DEPARTING SFC TROUGH
HOLDS ON OVER WARMER LAKE WATERS. COULD SEE AN IMPRESSIVE LES BAND
IN FAR NORTHERN LUCE TO NORTHERN CHIPPEWA COUNTIES. LOCATIONS VERY
NEAR LAKE SUPERIOR EAST OF GRAND MARAIS COULD SEE IN EXCESS OF 8
INCHES...WITH SOME LOCATIONS CLOSER TO WHITEFISH POINT POSSIBLY
SURPASSING A FOOT...TUESDAY NIGHT INTO WEDNESDAY MORNING. A LOT HAS
TO BE IRONED OUT WITH BAND PLACEMENT...SO DID NOT ISSUE AN LES WATCH
ATTM.
A WEAK AND BROAD TROUGH AXIS CROSSING THE AREA WEDNESDAY WILL ONLY
ENHANCE SOME LOW-LEVEL CLOUDINESS AND ASSIST IN KEEPING TEMPS EVEN
COLDER FOR THE DAY. WITH H8 TEMPS AT -25C AND CONTINUOUS CAA
THROUGHOUT THE DAY...INTERIOR WEST LOCATIONS...ESPECIALLY ALONG THE
WI BORDER...MAY FAIL TO GET ABOVE ZERO IN THE AFTERNOON. THE SFC
WIND FIELD BECOMES A BIT MUDDLED WEDNESDAY NIGHT AS A WEAK SFC LOW
TRACKS SE ACROSS IA...BUT A WEAK SFC RIDGE SHOULD KEEP WINDS LIGHT
AND ALLOW TEMPS TO PLUMMET ACROSS THE CWA. DID BUMP TEMPS BACK UP A
COUPLE DEGREES THOUGH AS MID-LEVEL CLOUDINESS MAY BE ON THE RISE
LATE IN THE NIGHT WITH THE APPROACH OF AN UPPER JET AND SUBTLE
MID-LEVEL TROUGH. WITH THAT SAID...SOME OF THE COLDEST LOCATIONS
ACROSS THE CENTRAL CWA COULD SEE TEMPS FALL AS LOW AS -20F. THOUGH
WINDS WILL BE LIGHT...WIND CHILLS WILL STILL DROP AS LOW AS -35F FOR
THE COLDEST LOCATIONS.
THURSDAY THROUGH SUNDAY...DID NOT FOCUS HEAVILY ON THIS PERIOD GIVEN
SOME MODEL DISAGREEMENT. USED THE ECMWF HEAVILY AS THE GFS HAS
DEVELOPED SOME CONTINUITY ISSUES OVER THE PAST FEW RUNS. OVERALL
PATTERN BEGINS TO CHANGE SOMEWHAT...THOUGH TEMPS WILL REMAIN WELL
BELOW NORMAL. A WEAK CLIPPER SYSTEM LOOKS TO BRING ANOTHER ROUND OF
VERY LIGHT SNOW THURSDAY...BUT ONCE AGAIN...OVERALL SUPPORT IS
MINIMAL. AN ASSOCIATED SFC TROUGH WILL LAY OUT ACROSS THE UPPER MS
VALLEY THROUGH FRIDAY. COMBINED WITH THE RIGHT ENTRANCE OF THE
PASSING UPPER JET...SOME MINOR SYNOPTIC SNOW IS POSSIBLE
FRIDAY...BUT DID NOT PLACE MORE THAN SLIGHT CHANCE POPS AWAY FROM
LAKE SUPERIOR. PLENTY OF CLOUD COVERED AND CONTINUED LES FOR NW SNOW
BELTS SHOULD LAST INTO SATURDAY...BUT MUCH LOWER INVERSION HEIGHTS
WILL LIKELY PREVENT ANY SIGNIFICANT ACCUMULATIONS. WHAT WAS STARTING
TO LOOK LIKE A WARMING TREND THROUGH THE WEEKEND MAY BE HALTED BY
YET ANOTHER CLIPPER SYSTEM TRACKING SE ACROSS THE AREA ON SUNDAY.
COLDER AIR WILL WRAP AROUND THIS AND KEEP TEMPS DOWN INTO EARLY NEXT
WEEK.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z MONDAY NIGHT)
ISSUED AT 1155 PM EST SUN DEC 8 2013
WIDESPREAD LIGHT SNOW WILL CONTINUE TONIGHT WITH MVFR/IFR CONDITIONS
CONTINUING OVERNIGHT. CONDITIONS SHOULD IMPROVE TO MVFR BY LATE
TONIGHT OR MON MORNING AT IWD AND SAW. LAKE EFFECT SNOW WITH VLIFR
VSBY IS EXPECTED AT CMX BY MID MORNING AS WINDS VEER TO THE WEST AND
BECOME GUSTY AND THIS WILL CONTINUE THROUGH THE REST OF THE TAF
PERIOD.
&&
.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 551 AM EST MON DEC 9 2013(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 400 PM EST SUN DEC 8 2013
A SERIES OF TROUGHS WILL CROSS LAKE SUPERIOR THROUGH THE UPCOMING
WEEK AND BRING MULTIPLE CHANCES FOR GALES. THE FIRST TROUGH WILL
PASS ACROSS LAKE SUPERIOR LATE THIS MORNING/AFTERNOON VEERING WINDS
TO THE WEST AND INCREASING THEM TO GALES TO 35 TO 40 KNOTS ACROSS
LAKE SUPERIOR 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...
WINTER WEATHER ADVISORY UNTIL 9 AM EST THIS MORNING FOR MIZ014-
085.
LAKE EFFECT SNOW ADVISORY UNTIL 7 AM EST TUESDAY FOR MIZ001-003.
LAKE SUPERIOR...
HEAVY FREEZING SPRAY WARNING FROM 7 PM THIS EVENING TO 7 AM EST
TUESDAY FOR LSZ245-248>251-265>267.
GALE WARNING FROM 1 PM THIS AFTERNOON TO 5 AM EST TUESDAY FOR
LSZ244-245-265>267.
HEAVY FREEZING SPRAY WARNING FROM 1 PM EST /NOON CST/ THIS
AFTERNOON TO 7 AM EST /6 AM CST/ TUESDAY FOR LSZ162-240>244-
263-264.
GALE WARNING FROM 4 PM THIS AFTERNOON TO 5 AM EST TUESDAY FOR
LSZ264.
GALE WARNING FROM 1 PM EST /NOON CST/ THIS AFTERNOON TO 10 PM
EST /9 PM CST/ THIS EVENING FOR LSZ241>243-246-247.
GALE WARNING FROM 1 PM THIS AFTERNOON TO MIDNIGHT EST TONIGHT
FOR LSZ263.
LAKE MICHIGAN...
GALE WARNING FROM 4 PM THIS AFTERNOON TO 10 PM EST THIS EVENING
FOR LMZ221-248-250.
&&
$$
SHORT TERM...VOSS
LONG TERM...KLUBER
AVIATION...07
MARINE...VOSS
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
520 AM EST MON DEC 9 2013
.SHORT TERM...(THIS EVENING THROUGH MONDAY)
ISSUED AT 400 PM EST SUN DEC 8 2013
WV IMAGERY AND RUC ANALYSIS INDICATED A BROAD MID/UPPER LEVEL TROUGH
OVER THE WRN CONUS RESULTING IN WSW FLOW FROM THE PLAINS INTO THE
GREAT LAKES. THE MAIN UPSTREAM SHORTWAVE TROUGH WAS MOVING THROUGH
SE CO. AT THE SFC...LIGHT WINDS PREVAILED ACROSS UPPER MICHIGAN AS
ARCTIC HIGH PRES EXTENDED FROM NEW ENGLAND INTO THE NRN GREAT LAKES.
A LOW PRES TROUGH STRETCHED FROM SW KS THROUGH THE OH VALLEY. A
BROAD AREA OF LIGHT SNOW SUPPORTED BY WAA/280K-290K ISENTROPIC
LIFT...HAD SPREAD FROM MN/IA/WI INTO UPPER MI. HOWEVER...SNOW HAS
BEEN VERY LIGHT WITH VSBY TO 2-4SM FROM MNM-ESC AND ABOVE 5SM FROM
IMT-IWD.
LATE THIS AFTERNOON AND TONIGHT...AS THE SHORTWAVE CONTINUES TO LIFT
TOWARD THE GREAT LAKES EXPECT THE SNOW INTENSITY TO SLOWLY INCREASE.
HOWEVER...WITH THE STRONGER 700-300 MB QVECTOR CONV REMAINING SOUTH
OF THE AREA AND ONLY 1-2 G/KG AVAILABLE...GOING QPF VALUES IN THE
0.08-0.20 RANGE REMAIN ON TRACK. EXPECT SLR VALUES FROM NEAR 20/1
SOUTH TO 15/1 NORTH AS THE DGZ IS DEEPER AND EXTENDS MORE FAVORABLY
INTO THE LAYER OF GREATER UPWARD MOTION OVER THE SOUTH COMPARED TO
THE SHALLOW DGZ FARTHER NORTH IN THE COLDER AIR.
SO...FCST SNOWFALL AMOUNTS OF AROUND AN INCH NORTH TO 1 TO 3 INCHES
SOUTH ARE INCLUDED. THE HIGHER RES MODELS SUGGEST THAT AN AREA OF
LOW LEVEL CONV OVER NRN LAKE MI AHEAD OF THE AREA OF STRONGER SE
WINDS MAY PUSH A BAND OF LAKE ENHANCED SNOW INTO LOCATIONS BORDER
THE BAY OF GREEN BAY AND LAKE MICHIGAN LATE THIS EVENING. SINCE THE
BAND IS EXPECTED TO BE TRANSIENT...ADDITIONAL SNOW AMOUNTS OF ONLY
AN INCH OR TWO ARE EXPECTED WITH THIS FEATURE. A PERIOD OF SRLY
WINDS INTO SCHOOLCRAFT COUNTY COULD ALSO BRING A PERIOD OF MODERATE
SNOW LATE TONIGHT.
MONDAY...THE FIRST OF SEVERAL EMBEDDED SHORTWAVE TROUGHS WITHIN THE
DEEP EASTERN CANADIAN TROUGH WILL BE PUSHING THROUGH THE AREA MONDAY
MORNING. THE NEXT INTRUSION OF ARCTIC AIR WILL BE PUSHING INTO THE
WESTERN CWA BEHIND A COLD FRONT AT THE START OF THE PERIOD. 850 MB
TEMPS FALLING TO -21 TO -23C BY THE AFTERNOON COMBINED WITH
INVERSION HEIGHTS RISING TO 8K-10K FT AND UNIDIRECTIONAL WESTERLY
WINDS SHOULD RESULT IN FAVORABLE LOW LEVEL CONV AND POTENTIAL FOR A
DOMINANT LES BAND INTO THE NRN KEWEENAW PENINSULA. WITH THE PASSAGE
OF THE SHRTWV...EXPECT THAT THE WINDS WOULD EVENTUALLY
VEER...PUSHING THE BAND SLOWLY TO THE SOUTH FROM NEAR EAGLE RIVER TO
CALUMET/MOHAWK AND TO HOUGHTON IN THE AFTERNOON. SNOWFALL
ACCUMULATIONS WILL GREATLY DEPEND ON HOW THE HEAVIER BAND LINGERS IN
ANY ONE LOCATION...BUT 12 HOUR ACCUMULATIONS OF AT LEAST 8 INCHES
REMAIN POSSIBLE. IN ADDITION...BLUSTERY WEST WINDS OF 20-30MPH WITH
GUSTS OVER 35 MPH WILL PRODUCE CONSIDERABLE BLOWING AND DRIFTING
SNOW AND VERY LOW VSBY. HOWEVER...SINCE THE HIGHER RES MODELS STILL
SHOW DIFFERENCES IN HANDLING WHERE THE BAND WILL DEVELOP AND HOW
LONG IT WILL LINGER...THE WATCH WAS NOT UPGRADED AT THIS TIME.
.LONG TERM...(TUESDAY THROUGH SUNDAY)
ISSUED AT 519 AM EST MON DEC 9 2013
CONTINUED NW FLOW ALOFT THROUGH THE WEEK WILL BRING LAKE EFFECT SNOW
FOR W TO NW FAVORED SNOW BELTS OFF AND ON. FOR THE REST OF UPPER
MI...ONLY BRIEF ROUNDS OF LIGHT SYNOPTIC SNOWFALL ARE EXPECTED.
ARCTIC AIR WILL REMAIN ANCHORED ACROSS THE REGION WITH MULTIPLE
REINFORCING SHOTS THROUGH THIS WEEKEND.
TUESDAY...DEEP TROUGHING OVER EASTERN NORTH AMERICA WILL CONTINUE TO
SEND MULTIPLE WEAK TROUGHS THROUGH THE GREAT LAKES REGION. THE FIRST
OF THESE IS PROGGED TO IMPACT THE CWA AT THE BEGINNING OF THE
FORECAST PERIOD. MODEL AGREEMENT HAS BEEN DECENT OVER THE PAST
COUPLE OF DAYS...SO OVERALL CONFIDENCE IS GOOD. THE WEAK SHORTWAVE
TROUGH WILL TRACK EASTWARD ACROSS NORTHERN WI THROUGHOUT THE DAY
TUESDAY. BESIDE MID-LEVEL Q-VECTOR CONV WITH THE TROUGH...THERE WILL
BE LITTLE SYNOPTIC SUPPORT. THOUGH A SECONDARY SFC LOW FORMING OVER
NORTHERN LAKE MI TUESDAY AFTERNOON IN RESPONSE THE TO MID-LEVEL
TROUGH/WARMER LAKE TEMPS COULD BACK SFC WINDS TO THE SW AND BRING
SOME MINOR LAKE ENHANCEMENT TO THE FAR SE CWA...MINIMAL ADDITIONAL
ACCUMULATION IS EXPECTED. OVERALL...CANNOT FIND ANYTHING TO JUSTIFY
THIS BEING MORE THAN A DUSTING OF SNOW FOR MOST AREAS.
EXPECTED WNW LES WILL BE SLOW TO GET GOING TUESDAY AFTERNOON UNTIL
THE MAIN SFC-H8 TROUGHS PASS EARLY TUESDAY EVENING. A BRIEF BOUT OF
SNOW ALONG THESE TROUGHS WILL BE POSSIBLE...SO BROUGHT HIGHER POPS
INLAND ACROSS THE NORTHERN CWA A BIT MORE THAN PREVIOUS FORECAST.
TUESDAY NIGHT THROUGH WEDNESDAY NIGHT...BUMPED UP CLOUD COVER
TUESDAY NIGHT WITH LINGERING LOW-LEVEL MOISTURE AND NO REAL MEANS TO
GET RID OF IT. THIS IMPACTS LOW TEMPS...SO HAVE INCREASED THOSE A
DEGREE OR TWO. CLOUD COVER MAY CREATE SOME DISPARITY IN MIN TEMPS
ACROSS THE CWA...SO WOULD NOT BE SURPRISED IF ONLY PORTIONS OF THE
WEST HALF REACH THEIR FORECAST MIN TEMPS TO -10F.
LES PICKS UP IN INTENSITY WITH COLDER AIR CONTINUING TO ADVECT INTO
THE AREA. MODEL GUIDANCE IS PICKING UP ON CONSIDERABLE SFC
CONVERGENCE ALONG THE EASTERN SHORELINE AS THE DEPARTING SFC TROUGH
HOLDS ON OVER WARMER LAKE WATERS. COULD SEE AN IMPRESSIVE LES BAND
IN FAR NORTHERN LUCE TO NORTHERN CHIPPEWA COUNTIES. LOCATIONS VERY
NEAR LAKE SUPERIOR EAST OF GRAND MARAIS COULD SEE IN EXCESS OF 8
INCHES...WITH SOME LOCATIONS CLOSER TO WHITEFISH POINT POSSIBLY
SURPASSING A FOOT...TUESDAY NIGHT INTO WEDNESDAY MORNING. A LOT HAS
TO BE IRONED OUT WITH BAND PLACEMENT...SO DID NOT ISSUE AN LES WATCH
ATTM.
A WEAK AND BROAD TROUGH AXIS CROSSING THE AREA WEDNESDAY WILL ONLY
ENHANCE SOME LOW-LEVEL CLOUDINESS AND ASSIST IN KEEPING TEMPS EVEN
COLDER FOR THE DAY. WITH H8 TEMPS AT -25C AND CONTINUOUS CAA
THROUGHOUT THE DAY...INTERIOR WEST LOCATIONS...ESPECIALLY ALONG THE
WI BORDER...MAY FAIL TO GET ABOVE ZERO IN THE AFTERNOON. THE SFC
WIND FIELD BECOMES A BIT MUDDLED WEDNESDAY NIGHT AS A WEAK SFC LOW
TRACKS SE ACROSS IA...BUT A WEAK SFC RIDGE SHOULD KEEP WINDS LIGHT
AND ALLOW TEMPS TO PLUMMET ACROSS THE CWA. DID BUMP TEMPS BACK UP A
COUPLE DEGREES THOUGH AS MID-LEVEL CLOUDINESS MAY BE ON THE RISE
LATE IN THE NIGHT WITH THE APPROACH OF AN UPPER JET AND SUBTLE
MID-LEVEL TROUGH. WITH THAT SAID...SOME OF THE COLDEST LOCATIONS
ACROSS THE CENTRAL CWA COULD SEE TEMPS FALL AS LOW AS -20F. THOUGH
WINDS WILL BE LIGHT...WIND CHILLS WILL STILL DROP AS LOW AS -35F FOR
THE COLDEST LOCATIONS.
THURSDAY THROUGH SUNDAY...DID NOT FOCUS HEAVILY ON THIS PERIOD GIVEN
SOME MODEL DISAGREEMENT. USED THE ECMWF HEAVILY AS THE GFS HAS
DEVELOPED SOME CONTINUITY ISSUES OVER THE PAST FEW RUNS. OVERALL
PATTERN BEGINS TO CHANGE SOMEWHAT...THOUGH TEMPS WILL REMAIN WELL
BELOW NORMAL. A WEAK CLIPPER SYSTEM LOOKS TO BRING ANOTHER ROUND OF
VERY LIGHT SNOW THURSDAY...BUT ONCE AGAIN...OVERALL SUPPORT IS
MINIMAL. AN ASSOCIATED SFC TROUGH WILL LAY OUT ACROSS THE UPPER MS
VALLEY THROUGH FRIDAY. COMBINED WITH THE RIGHT ENTRANCE OF THE
PASSING UPPER JET...SOME MINOR SYNOPTIC SNOW IS POSSIBLE
FRIDAY...BUT DID NOT PLACE MORE THAN SLIGHT CHANCE POPS AWAY FROM
LAKE SUPERIOR. PLENTY OF CLOUD COVERED AND CONTINUED LES FOR NW SNOW
BELTS SHOULD LAST INTO SATURDAY...BUT MUCH LOWER INVERSION HEIGHTS
WILL LIKELY PREVENT ANY SIGNIFICANT ACCUMULATIONS. WHAT WAS STARTING
TO LOOK LIKE A WARMING TREND THROUGH THE WEEKEND MAY BE HALTED BY
YET ANOTHER CLIPPER SYSTEM TRACKING SE ACROSS THE AREA ON SUNDAY.
COLDER AIR WILL WRAP AROUND THIS AND KEEP TEMPS DOWN INTO EARLY NEXT
WEEK.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z MONDAY NIGHT)
ISSUED AT 1155 PM EST SUN DEC 8 2013
WIDESPREAD LIGHT SNOW WILL CONTINUE TONIGHT WITH MVFR/IFR CONDITIONS
CONTINUING OVERNIGHT. CONDITIONS SHOULD IMPROVE TO MVFR BY LATE
TONIGHT OR MON MORNING AT IWD AND SAW. LAKE EFFECT SNOW WITH VLIFR
VSBY IS EXPECTED AT CMX BY MID MORNING AS WINDS VEER TO THE WEST AND
BECOME GUSTY AND THIS WILL CONTINUE THROUGH THE REST OF THE TAF
PERIOD.
&&
.MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 400 PM EST SUN DEC 8 2013
A SERIES OF TROUGHS WILL CROSS LAKE SUPERIOR THROUGH THE UPCOMING
WEEK AND BRING MULTIPLE CHANCES OF GALES. THE FIRST WILL PASS
SOUTHEAST OF UPPER MI MONDAY MORNING. BEHIND THIS TROUGH...WINDS
WILL VEER TO THE WEST AND INCREASE TO GALES TO 35 TO 40 KNOTS ACROSS
LAKE SUPERIOR MONDAY AFTERNOON AND EVENING. AFTER A DECREASE TO 20
TO 30 KNOT SOUTHWEST WINDS TUESDAY MORNING...LOW PRESSURE WILL TRACK
EASTWARD ACROSS LAKE SUPERIOR ON TUESDAY AND PRODUCE ANOTHER ROUND
OF GALES 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...
WINTER WEATHER ADVISORY UNTIL 9 AM EST THIS MORNING FOR MIZ014-
085.
LAKE EFFECT SNOW ADVISORY UNTIL 7 AM EST TUESDAY FOR MIZ001-003.
LAKE SUPERIOR...
HEAVY FREEZING SPRAY WARNING FROM 7 PM THIS EVENING TO 7 AM EST
TUESDAY FOR LSZ245-248>251-265>267.
GALE WARNING FROM 1 PM THIS AFTERNOON TO 5 AM EST TUESDAY FOR
LSZ244-245-265>267.
HEAVY FREEZING SPRAY WARNING FROM 1 PM EST /NOON CST/ THIS
AFTERNOON TO 7 AM EST /6 AM CST/ TUESDAY FOR LSZ162-240>244-
263-264.
GALE WARNING FROM 4 PM THIS AFTERNOON TO 5 AM EST TUESDAY FOR
LSZ264.
GALE WARNING FROM 1 PM EST /NOON CST/ THIS AFTERNOON TO 10 PM
EST /9 PM CST/ THIS EVENING FOR LSZ241>243-246-247.
GALE WARNING FROM 1 PM THIS AFTERNOON TO MIDNIGHT EST TONIGHT
FOR LSZ263.
LAKE MICHIGAN...
GALE WARNING FROM 4 PM THIS AFTERNOON TO 10 PM EST THIS EVENING
FOR LMZ221-248-250.
&&
$$
SHORT TERM...JLB
LONG TERM...KLUBER
AVIATION...07
MARINE...JLB
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
1155 PM EST SUN DEC 8 2013
.SHORT TERM...(THIS EVENING THROUGH MONDAY)
ISSUED AT 400 PM EST SUN DEC 8 2013
WV IMAGERY AND RUC ANALYSIS INDICATED A BROAD MID/UPPER LEVEL TROUGH
OVER THE WRN CONUS RESULTING IN WSW FLOW FROM THE PLAINS INTO THE
GREAT LAKES. THE MAIN UPSTREAM SHORTWAVE TROUGH WAS MOVING THROUGH
SE CO. AT THE SFC...LIGHT WINDS PREVAILED ACROSS UPPER MICHIGAN AS
ARCTIC HIGH PRES EXTENDED FROM NEW ENGLAND INTO THE NRN GREAT LAKES.
A LOW PRES TROUGH STRETCHED FROM SW KS THROUGH THE OH VALLEY. A
BROAD AREA OF LIGHT SNOW SUPPORTED BY WAA/280K-290K ISENTROPIC
LIFT...HAD SPREAD FROM MN/IA/WI INTO UPPER MI. HOWEVER...SNOW HAS
BEEN VERY LIGHT WITH VSBY TO 2-4SM FROM MNM-ESC AND ABOVE 5SM FROM
IMT-IWD.
LATE THIS AFTERNOON AND TONIGHT...AS THE SHORTWAVE CONTINUES TO LIFT
TOWARD THE GREAT LAKES EXPECT THE SNOW INTENSITY TO SLOWLY INCREASE.
HOWEVER...WITH THE STRONGER 700-300 MB QVECTOR CONV REMAINING SOUTH
OF THE AREA AND ONLY 1-2 G/KG AVAILABLE...GOING QPF VALUES IN THE
0.08-0.20 RANGE REMAIN ON TRACK. EXPECT SLR VALUES FROM NEAR 20/1
SOUTH TO 15/1 NORTH AS THE DGZ IS DEEPER AND EXTENDS MORE FAVORABLY
INTO THE LAYER OF GREATER UPWARD MOTION OVER THE SOUTH COMPARED TO
THE SHALLOW DGZ FARTHER NORTH IN THE COLDER AIR.
SO...FCST SNOWFALL AMOUNTS OF AROUND AN INCH NORTH TO 1 TO 3 INCHES
SOUTH ARE INCLUDED. THE HIGHER RES MODELS SUGGEST THAT AN AREA OF
LOW LEVEL CONV OVER NRN LAKE MI AHEAD OF THE AREA OF STRONGER SE
WINDS MAY PUSH A BAND OF LAKE ENHANCED SNOW INTO LOCATIONS BORDER
THE BAY OF GREEN BAY AND LAKE MICHIGAN LATE THIS EVENING. SINCE THE
BAND IS EXPECTED TO BE TRANSIENT...ADDITIONAL SNOW AMOUNTS OF ONLY
AN INCH OR TWO ARE EXPECTED WITH THIS FEATURE. A PERIOD OF SRLY
WINDS INTO SCHOOLCRAFT COUNTY COULD ALSO BRING A PERIOD OF MODERATE
SNOW LATE TONIGHT.
MONDAY...THE FIRST OF SEVERAL EMBEDDED SHORTWAVE TROUGHS WITHIN THE
DEEP EASTERN CANADIAN TROUGH WILL BE PUSHING THROUGH THE AREA MONDAY
MORNING. THE NEXT INTRUSION OF ARCTIC AIR WILL BE PUSHING INTO THE
WESTERN CWA BEHIND A COLD FRONT AT THE START OF THE PERIOD. 850 MB
TEMPS FALLING TO -21 TO -23C BY THE AFTERNOON COMBINED WITH
INVERSION HEIGHTS RISING TO 8K-10K FT AND UNIDIRECTIONAL WESTERLY
WINDS SHOULD RESULT IN FAVORABLE LOW LEVEL CONV AND POTENTIAL FOR A
DOMINANT LES BAND INTO THE NRN KEWEENAW PENINSULA. WITH THE PASSAGE
OF THE SHRTWV...EXPECT THAT THE WINDS WOULD EVENTUALLY
VEER...PUSHING THE BAND SLOWLY TO THE SOUTH FROM NEAR EAGLE RIVER TO
CALUMET/MOHAWK AND TO HOUGHTON IN THE AFTERNOON. SNOWFALL
ACCUMULATIONS WILL GREATLY DEPEND ON HOW THE HEAVIER BAND LINGERS IN
ANY ONE LOCATION...BUT 12 HOUR ACCUMULATIONS OF AT LEAST 8 INCHES
REMAIN POSSIBLE. IN ADDITION...BLUSTERY WEST WINDS OF 20-30MPH WITH
GUSTS OVER 35 MPH WILL PRODUCE CONSIDERABLE BLOWING AND DRIFTING
SNOW AND VERY LOW VSBY. HOWEVER...SINCE THE HIGHER RES MODELS STILL
SHOW DIFFERENCES IN HANDLING WHERE THE BAND WILL DEVELOP AND HOW
LONG IT WILL LINGER...THE WATCH WAS NOT UPGRADED AT THIS TIME.
.LONG TERM...(MONDAY NIGHT THROUGH SUNDAY)
ISSUED AT 400 PM EST SUN DEC 8 2013
ELOGATED AREA OF UPPER LEVEL TROUGHING STRETCHES FROM SKANDINAVIA
AND FAR NORTHWEST RUSSIA ACROSS THE NORTH POLE AND ACROSS MUCH OF
EASTERN CANADA AND AS FAR SOUTH AS THE WESTERN PORTIONS OF THE
CONUS. CORE OF COLDEST AIR RESIDES FROM NORTHERN GREENLAND ACROSS
CNTRL CANADA AND INTO THE NORTHERN PLAINS. H85 TEMP THIS MORNING
AT KINL WAS -25C WHILE IT WAS -17C AT KGRB. DECENT AGREEMENT THAT
UPCOMING WEEK WILL REMAIN CHILLY AS UPPER TROUGH BECOMES MORE
CENTERED OVER HUDSON BAY ALLOWING MULTIPLE PUSHES OF ARCTIC AIR TO
SWEEP ACROSS NORTHERN PLAINS AND GREAT LAKES IN NW FLOW ALOFT.
STILL INDICATIONS THAT COLD STARTS TO RELAX NEXT WEEKEND AS
TROUGHING REORIENTS FROM NORTH POLE TO DAVIS STRAIT AND GREENLAND
WHICH ALLOWS FOR MORE OF A ZONAL WEST-NORTHWEST FLOW ALOFT ACROSS
THE CONUS BY MIDDLE OF THE MONTH.
FIRST CONCERNING THE LK EFFECT ON MONDAY NIGHT. INITIAL SHORTWAVE IN
NW FLOW CURRENTLY OVER NORTHERN SASKATCHEWAN AND MANITOBA SWEEPS
ACROSS LK SUPERIOR REGION MONDAY AFTN. EXPECT MINIMAL SYNOPTIC
SUPPORT FOR ANY SNOW AS PVA/Q-VECTOR CONVERGENCE AT H7-H5/H85-H7
STAYS OVER LK SUPERIOR AND MAINLY NORTH. SFC LOW MOVING THROUGH ON
MONDAY DEEPENS NORTH OF LK SUPERIOR TOWARD JAMES BAY BY MONDAY
EVENING AS RESULT OF PVA/COLD AIR ADVECTION. RESULT IS INCREASING
UNSTABLE WESTERLY LOW- LEVEL FLOW ACROSS LK SUPERIOR. NAM SOUNDINGS
INDICATE VERY UNSTABLE CONDITIONS AS SHORTWAVE HELPS RAISE INVERSIONS
TO OVER 7KFT WITH LAKE EQL/S OVER 13KFT AT CMX AND P59 AND STDM4.
SFC-925MB STEERING WINDS VARY ENOUGH DURING PERIOD OF MOST FAVORABLE
INSTABILITY/MOSITURE/CONVERGENCE TO PEG WHERE HEAVIEST SNOW WILL
OCCUR. HIGH RES MODELS DO DIFFER HERE SOMEWHAT...WITH THE 12Z
REGIONAL GEM KEEPING THE STRONGEST CONVERGENCE MAINLY ALONG THE
NORTHWEST SHORE OF THE KEWEENAW THROUGH LATE AFTN...WHILE LOCAL WRF
IS MORE ON THE SOUTHERN EDGE...SETTING UP DOMINANT BAND MAINLY TO
SOUTH OF HOUGHTON AND HANCOCK. NAM AND NCEP WRF-ARW/NMM NESTS KIND OF
IN BTWN THOSE IDEAS. GIVEN THE DEGREE OF OVERWATER INSTABILITY...
POTENTIAL CERTAINTY THERE FOR TOTAL SNOW MONDAY AFTN THROUGH MONDAY
EVENING TO EXCEED A FOOT...IF THE BAND CAN PERSIST IN ONE LOCATION
FOR A WHILE. AT THE LEAST...MOST AREAS WILL SEE BURSTS OF HEAVIER
SNOW ALONG WITH STRONG/GUSTY WEST WINDS TO 40 MPH AND A LOT OF
BLOWING SNOW AND POOR VSBY. IN THE HEAVIER SNOW BAND...WHITEOUTS MAY
OCCUR MONDAY AFTN INTO MONDAY EVENING.
COORD WITH SHORT TERM FORECASTER AND DECIDED TO LEAVE GOING LK
EFFECT SNOW WATCH. NOT REALLY A QUESTION IF HEAVY LES/BLSN WILL
OCCUR...BUT MORE ONE OF WHERE THAT STRONG CONVERGENCE BAND WILL
DEVELOP. WILL LET MID SHIFT TAKE ANOTHER CRACK AT PINNING DOWN
LOCATION OF THE HEAVIER SNOW BAND.
ATTN LATER MONDAY NIGHT WILL BE ON SHORTWAVE PUSHING IN ACROSS
NORTHERN PLAINS AND ASSOCIATED SFC TROUGH. FIRST IMPACT FM THIS
WAVE WILL BE TO BACK WINDS SW...ALLOWING MOST OF HEAVIER LK EFFECT
SNOW TO PUSH OUT OVER LK SUPERIOR OFF THE KEWEENAW PENINSULA...THUS
THE ENDING TIME OF LATE MONDAY EVENING FOR LAKE EFFECT SNOW WATCH.
RIGHT AS THE LK EFFECT DIMINISHES FOR A WHILE...STILL APPEARS THAT
LGT SYNOPTIC SNOW WILL IMPACT MUCH OF CWA MAINLY IN THE MORNING.
BRIEF NOTE ABOUT WIND CHILLS FOR MONDAY NIGHT...INCREASING CLOUDS
AHEAD OF THE SYSTEM LATER MONDAY NIGHT SHOULD ALLOW TEMPS TO BEGIN TO
RISE. HAVE MINS WELL BLO ZERO...EVEN LESS THAN 10 BLO THROUGH EARLY
MORNING...THEN WITH THE ARRIVAL OF CLOUDS AND MORE WIND...EXPECT
TEMPS TO RISE TOWARD ZERO BY DAYBREAK ON TUESDAY. WILL BE CLOSE CALL
ON WIND CHILL READINGS NEAR CRITERIA BUT TEMPS MAY WARM JUST ENOUGH
TO KEEP WIND CHILLS GREATER THAN 25 BLO. AT THE LEAST...WIND CHILLS
WILL STILL BE A RATHER CHILLY 10 TO 20 BLO FOR MAJORITY OF WEST HALF
OF UPR MICHIGAN.
AS SFC LOW STRENGTHENS...MOISTURE/TEMPERATURE ADVECTION AHEAD OF
WAVE MIGHT RESULT IN MORE WIDESPREAD SNOW OVER EASTERN CWA LATE
MORNING INTO EARLY AFTN...WHERE A FEW INCHES OF SNOW COULD OCCUR.
OTHERWISE...EXPECT LESS THAN 1 INCH FOR THE CWA FROM THE SYSTEM.
ONCE THE SHORTWAVE AND SFC LOW CROSS THE AREA...SFC TROUGH ELONGATES
ACROSS SOUTHERN HALF OF LK SUPERIOR AND EVENTUALLY INTO NORTHERN
TIER OF UPR MICHIGAN. RESULT WILL BE LK EFFECT...MOSTLY OF MODERATE
INTENSITY...FOR THE WNW-NW FLOW AREAS. MOST CONCENTRATED/HEAVIER
SNOW SHOWERS LIKELY FOR THE SNOWBELTS OF ONTONAGON COUNTY FROM WHITE
PINE TO ROCKLAND AND ALSO TO THE EAST OF MUNISING AND TO THE NORTH
OF NEWBERRY...INCLUDING GRAND MARAIS. PERSISTENT LK EFFECT SETUP
CONTINUES THROUGH MUCH OF WEDNESDAY WITH INVERSIONS 5-8KFT AND
MORE THAN SUFFICIENT OVER-WATER INSTABILITY AS H85 TEMPS ARE NEAR
-25C. GIVEN SUCH COLD TEMPS THOUGH...SNOW WILL BE VERY FINE AND
MAIN ISSUE IN THE LK EFFECT AREAS WILL BE POWDERY SNOW BEING BLOWN
AROUND BY GUSTY WINDS RESULTING IN BLSN/POOR VSBY. AWAY FM THE LK
EFFECT COLD AIRMASS FIRMLY ENTRENCHED. SOME AREAS OF WESTERN CWA MAY
NOT REACH ZERO ON WEDNESDAY AFTN.
ANOTHER SYSTEM APPROACHING IN THE ACTIVE NW FLOW ALOFT COMES IN BY
THURSDAY MORNING. WINDS SHOULD BACK ENOUGH SW TO PUSH MOST OF THE LK
EFFECT OFFSHORE EXCEPT OVER THE KEWEENAW. HIGH PRESSURE RIDGE IN
VCNTY FIRST PART OF WED NIGHT WITH SUCH COLD AIRMASS SUGGESTS THAT
MINS COULD BE VERY LOW. LOWERED TEMPS TOWARD COLDER MOS NUMBERS...AND
FURTHER TWEAKED COLD SPOTS IN THE INTERIOR TOWARD 20 BLO ZERO. MAY BE
SIMILAR SETUP TO MONDAY NIGHT/TUESDAY NIGHT WHERE TEMPS RISE LATE.
MAIN CHANGE BESIDES LOWERING TEMPS WAS TO LOWER WIND SPEEDS TOO AS
WINDS MAY TRY TO GO CALM WITH THE RIDGE AROUND TO START THE NIGHT.
THUS...MAY NOT SEE WIND CHILL ISSUES UNLESS THAT INCOMING SYSTEM
TRENDS STRONGER.
IN WAKE OF THAT SYSTEM...SFC TROUGH SINKS ACROSS LK SUPERIOR AND UPR
MICHIGAN WHICH TURNS WINDS MORE NNW/N LATER THURSDAY AND FRIDAY.
KEPT IDEA OF INCREASING POPS FOR LK EFFECT ALONG MUCH OF LK SUPERIOR
COMPARED TO CONSENSUS POPS. MODELS HINT THAT WARMER AIR COULD TRY TO
WORK IN BY NEXT WEEKEND...AT LEAST RELATIVELY WARMER...AS FLOW SHOWS
SIGNS OF TRYING TO BECOME MORE ZONAL. MORE WIDESPREAD AREA OF WARM
AIR ADVECTION SNOW MAY TRY TO DEVELOP CLOSE TO THE REGION ALONG
RETREATING ARCTIC AIRMASS. THOSE TYPE OF DETAILS WILL BE HANDLED BY
LOW CHANCE POPS FOR THE TIME BEING. TEMPS THOUGH WARMER WILL STILL
BE RUNNING BLO NORMAL THROUGH THE END OF THE EXTENDED.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z MONDAY NIGHT)
ISSUED AT 1155 PM EST SUN DEC 8 2013
WIDESPREAD LIGHT SNOW WILL CONTINUE TONIGHT WITH MVFR/IFR CONDITIONS
CONTINUING OVERNIGHT. CONDITIONS SHOULD IMPROVE TO MVFR BY LATE
TONIGHT OR MON MORNING AT IWD AND SAW. LAKE EFFECT SNOW WITH VLIFR
VSBY IS EXPECTED AT CMX BY MID MORNING AS WINDS VEER TO THE WEST AND
BECOME GUSTY AND THIS WILL CONTINUE THROUGH THE REST OF THE TAF
PERIOD.
&&
.MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 400 PM EST SUN DEC 8 2013
A SERIES OF TROUGHS WILL CROSS LAKE SUPERIOR THROUGH THE UPCOMING
WEEK AND BRING MULTIPLE CHANCES OF GALES. THE FIRST WILL PASS
SOUTHEAST OF UPPER MI MONDAY MORNING. BEHIND THIS TROUGH...WINDS
WILL VEER TO THE WEST AND INCREASE TO GALES TO 35 TO 40 KNOTS ACROSS
LAKE SUPERIOR MONDAY AFTERNOON AND EVENING. AFTER A DECREASE TO 20
TO 30 KNOT SOUTHWEST WINDS TUESDAY MORNING...LOW PRESSURE WILL TRACK
EASTWARD ACROSS LAKE SUPERIOR ON TUESDAY AND PRODUCE ANOTHER ROUND
OF GALES 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...
WINTER WEATHER ADVISORY UNTIL 9 AM EST MONDAY FOR MIZ007-014-085.
LAKE EFFECT SNOW ADVISORY FROM 7 AM MONDAY TO 7 AM EST TUESDAY
FOR MIZ001-003.
WINTER WEATHER ADVISORY UNTIL 7 AM EST /6 AM CST/ MONDAY FOR
MIZ012-013.
LAKE SUPERIOR...
HEAVY FREEZING SPRAY WARNING FROM 7 PM MONDAY TO 7 AM EST
TUESDAY FOR LSZ245-248>251-265>267.
GALE WARNING FROM 1 PM MONDAY TO 5 AM EST TUESDAY FOR LSZ244-245-
265>267.
HEAVY FREEZING SPRAY WARNING FROM 1 PM EST /NOON CST/ MONDAY TO
7 AM EST /6 AM CST/ TUESDAY FOR LSZ162-240>244-263-264.
GALE WARNING FROM 4 PM MONDAY TO 5 AM EST TUESDAY FOR LSZ264.
GALE WARNING FROM 1 PM MONDAY TO MIDNIGHT EST MONDAY NIGHT FOR
LSZ263.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...JLB
LONG TERM...JLA
AVIATION...07
MARINE...JLB
AREA FORECAST DISCUSSION...UPDATED
NWS BILLINGS MT
1244 PM MST MON DEC 9 2013
.UPDATE...
MAKING ANOTHER QUICK UPDATE THIS MORNING TO ACCOUNT FOR THE
EXPIRATION OF THE WIND CHILL ADVISORY THAT IS REPLACED WITH A
WINTER WEATHER ADVISORY. OTHERWISE...THE GOING FORECAST APPEARS
TO BE IN GOOD SHAPE. AAG
&&
.SHORT TERM...VALID FOR TDY AND TUE...
WIND-RELATED WINTER WEATHER ISSUES TODAY WILL TRANSITION BACK TO A
HIGH PROBABILITY OF 1 TO 2 INCHES OF SNOW IN MANY AREAS TUE AS TWO
SHORT WAVES CROSS THE REGION IN STRONG NORTHWEST FLOW ALOFT. WE DO
STILL EXPECT A SLOW MODERATION IN TEMPERATURES TO CONTINUE THOUGH.
TODAY...LEE-SIDE SURFACE PRESSURE FALLS ON THE ORDER OF 5 HPA/3 HR
CENTERED ACROSS THE CENTRAL ALBERTA-SASKATCHEWAN BORDER EARLY THIS
MORNING WILL REACH NORTHEAST MT AND WESTERN ND BY MIDDAY. THE WIND
SPEEDS IN SOUTH CENTRAL MT WILL CONTINUE RAMPING UP AS THAT OCCURS
AND WILL BE BOOSTED FURTHER BY EXTRA PRESSURE GRADIENT THANKS TO A
FORMIDABLE COLD AIR MASS TRAPPED WEST OF THE LOCAL MOUNTAINS. WIND
SPEEDS IN THE GRIDDED FORECAST WERE HEAVILY WEIGHTED TO RAP OUTPUT
SINCE IT IS HANDLING EARLY-DAY WINDS NEAR BIG TIMBER /WHICH IS THE
FAVORED SPOT FOR THE HIGHEST SPEEDS IN THIS PATTERN/ WELL. WE THUS
HAVE HIGH CONFIDENCE IN SUSTAINED SPEEDS OF 40 TO 50 MPH AND GUSTS
TO 70 MPH FROM LIVINGSTON TO BIG TIMBER TODAY...AND GUSTS UP TO 55
MPH AT HARLOWTON AND 45 MPH AROUND BILLINGS TOO. THE WINDS WILL BE
ON THE INCREASE ON THE PLAINS OF SOUTH CENTRAL AND SOUTHEAST MT BY
21 UTC AS WELL AS MIXING INCREASES AND A MODEST BATCH OF LOW-LEVEL
HEIGHT RISES BEGINS AFFECTING THAT AREA...THOUGH MOMENTUM TRANSFER
WILL BE LACKING AND ONLY SUPPORTS GUSTS TO ABOUT 35 MPH ACROSS THE
SOUTHEAST PART OF MT. ADD IN SNOW SHOWERS WHICH COULD DROP A QUICK
INCH OF SNOW AND REDUCE VISIBILITY ON THEIR OWN TOO OVER SOUTHEAST
MT THOUGH...AND CONDITIONS COULD BE QUITE HAZARDOUS OVER THAT AREA
AS WELL. WE ACTUALLY PUSHED POPS FOR SNOW SHOWER ACTIVITY INTO THE
70-90 PERCENT RANGE OVER SOUTHEAST MT THIS AFTERNOON BASED ON GOOD
AGREEMENT IN 00 UTC GUIDANCE IN NOTABLE QG-FORCING OVER THAT AREA.
NEEDLESS TO SAY...BLOWING AND DRIFTING SNOW IS MENTIONED TODAY AND
INTO THIS EVENING FOR MOST OF THE AREA...THOUGH DEPTH AND PHYSICAL
CHARACTERISTICS OF THE SNOW SUGGEST THE BIGGEST ISSUE COULD END UP
BEING SIGNIFICANT DRIFTING. WE WILL NONETHELESS NEED TO BE WARY OF
THE POSSIBILITY OF BONAFIDE GROUND BLIZZARD CONDITIONS IN THE OPEN
COUNTRY WHERE LOCALLY DEEPER SNOW PACK RESIDES...THOUGH THE CHANCE
OF THAT APPEARS RELATIVELY LOW /SUBJECTIVELY NEAR 30 PERCENT/.
WHERE HEADLINES ARE CONCERNED...WE ADDED ALL OF BIG HORN COUNTY TO
A WINTER WEATHER ADVISORY FROM 18 TO 06 UTC SINCE OUR RAP-WEIGHTED
WIND FORECAST SUPPORTED SPEEDS SUFFICIENT FOR BLOWING AND DRIFTING
SNOW ISSUES THERE TOO. THE REST OF OUR PREVIOUSLY-ISSUED HEADLINES
WERE LEFT IN TACT. WE WILL PROBABLY HIT HIGH WIND CRITERIA FOR THE
SUSTAINED 50 MPH SPEEDS AT BIG TIMBER TODAY...BUT FELT IT WAS BEST
TO COVER THIS WITH ONE PRODUCT...THE WINTER WEATHER ADVISORY. NOTE
THAT IF WINDS IN SOUTH CENTRAL MT /NAMELY IN THE LIVINGSTON TO BIG
TIMBER CORRIDOR/ STAY UP PAST 12 UTC TUE MORNING AS SOME OF THE 00
UTC GUIDANCE SHOWS...PARTS OF THE ADVISORY MAY NEED TO BE EXTENDED
IN TIME WITH A LATER FORECAST RELEASE.
TONIGHT...THE SHORT WAVE WILL EXIT THE AREA...AND WINDS WILL BE ON
A DOWNWARD TREND /ESPECIALLY AFTER 06 UTC/...EVEN THOUGH THEY WILL
STAY GUSTY IN SOUTH CENTRAL MT. WE CAUTIOUSLY FOLLOWED THE LEAD OF
RECENTLY WELL-PERFORMING GUIDANCE THAT SHOWS LOWS ONLY AROUND 10 F
/MUCH WARMER THAN RECENT NIGHTS/ GIVEN EXPECTED LOW-LEVEL MIXING.
TUE...A LIGHT SNOW EVENT IS EXPECTED IN MANY AREAS AS A GOOD BATCH
OF QG-FORCING WITH ANOTHER SHORT WAVE TROUGH RIDES SOUTHEAST ALONG
THE THERMAL BOUNDARY LEFT BEHIND TODAY/S WAVE. IT LOOKS LIKE WINDS
WILL EVEN TURN NORTH OR NORTHEAST IN BILLINGS BY AFTERNOON...SO WE
WILL PROBABLY GET IN ON SOME LIGHT SNOW HERE TOO. WE HAD ENOUGH IN
THE WAY OF CONFIDENCE IN THIS WHOLE SCENARIO TO SIGNIFICANTLY RAMP
UP POPS IN MANY AREAS...GOING AS FAR AS 80 PERCENT FROM MILES CITY
TO HYSHAM AND DOWN TOWARD LAME DEER AND LODGE GRASS. THIS LOOKS TO
BE A GOOD 1 TO 2 INCH SNOW EVENT IN MANY AREAS. SCHULTZ
.LONG TERM...VALID FOR WED...THU...FRI...SAT...SUN...
NORTHWEST FLOW ALOFT ON WEDNESDAY SLOWLY BECOMES A MORE WESTERLY
FLOW ON THURSDAY WHICH WILL ALLOW A LEESIDE SURFACE PRESSURE
TROUGH TO BE THE DOMINANT FEATURE EAST OF THE CONTINENTAL DIVIDE.
THIS PATTERN HOLDS UNTIL LATER ON FRIDAY WHEN AN UPPER LEVEL RIDGE
BUILDING INTO THE PACIFIC NORTHWEST TURNS THE FLOW NORTHWESTERLY
OVER MONTANA AND WYOMING. AT SOME POINT COLDER AIR OVER THE
DAKOTAS WILL HAVE A CHANCE TO PUSH A BACKDOOR COLD FRONT INTO
SOUTHERN MONTANA BUT WHEN IS NOT EXACTLY SURE...WHETHER IT WILL BE
FRIDAY NIGHT OR SATURDAY NIGHT. THIS IS THE BEST CHANCE FOR SNOW
IN THE PLAINS DURING THE EXTENDED PERIOD...THOUGH THE MODELS WILL
HAVE CHANCES FOR OROGRAPHIC SHOWERS AS THE FLOW ALOFT CONTINUES TO
BE FAIRLY MOIST.
TEMPERATURES WEDNESDAY THROUGH FRIDAY ARE GOING TO BE GOVERNED BY
A COUPLE OF FACTORS. DOWNSLOPE WINDS WILL BE FAVORED ACROSS THE
WESTERN AND CENTRAL ZONES BUT AIR WEST OF THE DIVIDE IS SO COLD
THAT THE WARMUP WILL BE MUCH SLOWER THAN NORMAL FOEHN WINDS WOULD
CREATE. ALSO...SNOW COVER WILL REGULATE A PART OF THE WARMUP AND
THE POSITION OF THE SURFACE TROUGH WILL SHOW THE EASTWARD EXTENT
OF THE BEST WARMING WITH TEMPERATURES STAYING COOLER EAST OF THE
TROUGH. BY THE WEEKEND THE PUSH WESTWARD OF THE COLD FRONT WILL
SUPPORT A DROP OF TEMPERATURES BUT AGAIN HOW FAR WEST AND HOW
DRAMATIC IS STILL NOT CERTAIN. WITH COLDER AIR POOLED UP WEST OF
THE DIVIDE WIND IS GOING TO BE A OMNIPRESENT FEATURE FOR THE
WESTERN ZONES. BORSUM
&&
.AVIATION...
QUICK UPDATE FOR AVIATION CONDITIONS THIS AFTERNOON...A BAND OF
FAIRLY HEAVY SNOWFALL HAS CAUSED VISIBILITIES TO DETERIORATE RAPIDLY
AT KMLS AND KBHK. THIS COMBINED WITH VERY GUSTY WINDS AND PREVIOUS
SNOWFALL ON THE GROUND...WILL BRING WITH IT IFR CONDITIONS. THE
SNOW SHOWERS SHOULD END IN THE NEXT FEW HOURS... BUT THE GUSTY
WINDS WILL PERSIST INTO THE EVENING. SINGER
&&
.PRELIMINARY POINT TEMP/POPS...
TDY TUE WED THU FRI SAT SUN
-------------------------------------------------------
BIL 019 014/023 005/029 020/033 018/034 015/034 024/036
1/Q 16/S 51/B 11/B 11/B 11/B 11/B
LVM 016 010/022 007/026 020/032 021/034 019/032 024/033
2/J 24/S 42/J 11/N 12/J 11/B 11/N
HDN 022 012/022 901/027 014/035 015/032 012/032 022/036
2/J 28/S 51/B 11/B 11/E 11/B 12/B
MLS 020 009/016 907/023 010/031 013/026 010/028 020/035
9/J 38/S 21/B 11/B 12/J 11/B 22/B
4BQ 020 011/020 903/022 011/034 017/031 012/032 023/036
8/J 47/S 21/B 00/B 01/B 11/B 22/B
BHK 016 009/013 910/017 009/029 012/022 010/027 018/033
9/J 56/S 11/B 01/B 11/B 11/E 12/B
SHR 023 008/024 901/027 014/036 016/034 014/033 022/038
2/J 25/S 51/B 01/B 12/J 11/B 11/B
&&
.BYZ WATCHES/WARNINGS/ADVISORIES...
MT...WINTER WEATHER ADVISORY IN EFFECT UNTIL 5 AM MST TUESDAY FOR
ZONES 28-29-34-35-39-41-42-56-63-65-66.
WINTER WEATHER ADVISORY IN EFFECT UNTIL 11 PM MST THIS
EVENING FOR ZONES 30>33-36>38-57-58.
WY...NONE.
&&
$$
WEATHER.GOV/BILLINGS
AREA FORECAST DISCUSSION
NWS BILLINGS MT
1127 AM MST MON DEC 9 2013
.UPDATE...
MAKING ANOTHER QUICK UPDATE THIS MORNING TO ACCOUNT FOR THE
EXPIRATION OF THE WIND CHILL ADVISORY THAT IS REPLACED WITH A
WINTER WEATHER ADVISORY. OTHERWISE...THE GOING FORECAST APPEARS
TO BE IN GOOD SHAPE. AAG
&&
.SHORT TERM...VALID FOR TDY AND TUE...
WIND-RELATED WINTER WEATHER ISSUES TODAY WILL TRANSITION BACK TO A
HIGH PROBABILITY OF 1 TO 2 INCHES OF SNOW IN MANY AREAS TUE AS TWO
SHORT WAVES CROSS THE REGION IN STRONG NORTHWEST FLOW ALOFT. WE DO
STILL EXPECT A SLOW MODERATION IN TEMPERATURES TO CONTINUE THOUGH.
TODAY...LEE-SIDE SURFACE PRESSURE FALLS ON THE ORDER OF 5 HPA/3 HR
CENTERED ACROSS THE CENTRAL ALBERTA-SASKATCHEWAN BORDER EARLY THIS
MORNING WILL REACH NORTHEAST MT AND WESTERN ND BY MIDDAY. THE WIND
SPEEDS IN SOUTH CENTRAL MT WILL CONTINUE RAMPING UP AS THAT OCCURS
AND WILL BE BOOSTED FURTHER BY EXTRA PRESSURE GRADIENT THANKS TO A
FORMIDABLE COLD AIR MASS TRAPPED WEST OF THE LOCAL MOUNTAINS. WIND
SPEEDS IN THE GRIDDED FORECAST WERE HEAVILY WEIGHTED TO RAP OUTPUT
SINCE IT IS HANDLING EARLY-DAY WINDS NEAR BIG TIMBER /WHICH IS THE
FAVORED SPOT FOR THE HIGHEST SPEEDS IN THIS PATTERN/ WELL. WE THUS
HAVE HIGH CONFIDENCE IN SUSTAINED SPEEDS OF 40 TO 50 MPH AND GUSTS
TO 70 MPH FROM LIVINGSTON TO BIG TIMBER TODAY...AND GUSTS UP TO 55
MPH AT HARLOWTON AND 45 MPH AROUND BILLINGS TOO. THE WINDS WILL BE
ON THE INCREASE ON THE PLAINS OF SOUTH CENTRAL AND SOUTHEAST MT BY
21 UTC AS WELL AS MIXING INCREASES AND A MODEST BATCH OF LOW-LEVEL
HEIGHT RISES BEGINS AFFECTING THAT AREA...THOUGH MOMENTUM TRANSFER
WILL BE LACKING AND ONLY SUPPORTS GUSTS TO ABOUT 35 MPH ACROSS THE
SOUTHEAST PART OF MT. ADD IN SNOW SHOWERS WHICH COULD DROP A QUICK
INCH OF SNOW AND REDUCE VISIBILITY ON THEIR OWN TOO OVER SOUTHEAST
MT THOUGH...AND CONDITIONS COULD BE QUITE HAZARDOUS OVER THAT AREA
AS WELL. WE ACTUALLY PUSHED POPS FOR SNOW SHOWER ACTIVITY INTO THE
70-90 PERCENT RANGE OVER SOUTHEAST MT THIS AFTERNOON BASED ON GOOD
AGREEMENT IN 00 UTC GUIDANCE IN NOTABLE QG-FORCING OVER THAT AREA.
NEEDLESS TO SAY...BLOWING AND DRIFTING SNOW IS MENTIONED TODAY AND
INTO THIS EVENING FOR MOST OF THE AREA...THOUGH DEPTH AND PHYSICAL
CHARACTERISTICS OF THE SNOW SUGGEST THE BIGGEST ISSUE COULD END UP
BEING SIGNIFICANT DRIFTING. WE WILL NONETHELESS NEED TO BE WARY OF
THE POSSIBILITY OF BONAFIDE GROUND BLIZZARD CONDITIONS IN THE OPEN
COUNTRY WHERE LOCALLY DEEPER SNOW PACK RESIDES...THOUGH THE CHANCE
OF THAT APPEARS RELATIVELY LOW /SUBJECTIVELY NEAR 30 PERCENT/.
WHERE HEADLINES ARE CONCERNED...WE ADDED ALL OF BIG HORN COUNTY TO
A WINTER WEATHER ADVISORY FROM 18 TO 06 UTC SINCE OUR RAP-WEIGHTED
WIND FORECAST SUPPORTED SPEEDS SUFFICIENT FOR BLOWING AND DRIFTING
SNOW ISSUES THERE TOO. THE REST OF OUR PREVIOUSLY-ISSUED HEADLINES
WERE LEFT IN TACT. WE WILL PROBABLY HIT HIGH WIND CRITERIA FOR THE
SUSTAINED 50 MPH SPEEDS AT BIG TIMBER TODAY...BUT FELT IT WAS BEST
TO COVER THIS WITH ONE PRODUCT...THE WINTER WEATHER ADVISORY. NOTE
THAT IF WINDS IN SOUTH CENTRAL MT /NAMELY IN THE LIVINGSTON TO BIG
TIMBER CORRIDOR/ STAY UP PAST 12 UTC TUE MORNING AS SOME OF THE 00
UTC GUIDANCE SHOWS...PARTS OF THE ADVISORY MAY NEED TO BE EXTENDED
IN TIME WITH A LATER FORECAST RELEASE.
TONIGHT...THE SHORT WAVE WILL EXIT THE AREA...AND WINDS WILL BE ON
A DOWNWARD TREND /ESPECIALLY AFTER 06 UTC/...EVEN THOUGH THEY WILL
STAY GUSTY IN SOUTH CENTRAL MT. WE CAUTIOUSLY FOLLOWED THE LEAD OF
RECENTLY WELL-PERFORMING GUIDANCE THAT SHOWS LOWS ONLY AROUND 10 F
/MUCH WARMER THAN RECENT NIGHTS/ GIVEN EXPECTED LOW-LEVEL MIXING.
TUE...A LIGHT SNOW EVENT IS EXPECTED IN MANY AREAS AS A GOOD BATCH
OF QG-FORCING WITH ANOTHER SHORT WAVE TROUGH RIDES SOUTHEAST ALONG
THE THERMAL BOUNDARY LEFT BEHIND TODAY/S WAVE. IT LOOKS LIKE WINDS
WILL EVEN TURN NORTH OR NORTHEAST IN BILLINGS BY AFTERNOON...SO WE
WILL PROBABLY GET IN ON SOME LIGHT SNOW HERE TOO. WE HAD ENOUGH IN
THE WAY OF CONFIDENCE IN THIS WHOLE SCENARIO TO SIGNIFICANTLY RAMP
UP POPS IN MANY AREAS...GOING AS FAR AS 80 PERCENT FROM MILES CITY
TO HYSHAM AND DOWN TOWARD LAME DEER AND LODGE GRASS. THIS LOOKS TO
BE A GOOD 1 TO 2 INCH SNOW EVENT IN MANY AREAS. SCHULTZ
.LONG TERM...VALID FOR WED...THU...FRI...SAT...SUN...
NORTHWEST FLOW ALOFT ON WEDNESDAY SLOWLY BECOMES A MORE WESTERLY
FLOW ON THURSDAY WHICH WILL ALLOW A LEESIDE SURFACE PRESSURE
TROUGH TO BE THE DOMINANT FEATURE EAST OF THE CONTINENTAL DIVIDE.
THIS PATTERN HOLDS UNTIL LATER ON FRIDAY WHEN AN UPPER LEVEL RIDGE
BUILDING INTO THE PACIFIC NORTHWEST TURNS THE FLOW NORTHWESTERLY
OVER MONTANA AND WYOMING. AT SOME POINT COLDER AIR OVER THE
DAKOTAS WILL HAVE A CHANCE TO PUSH A BACKDOOR COLD FRONT INTO
SOUTHERN MONTANA BUT WHEN IS NOT EXACTLY SURE...WHETHER IT WILL BE
FRIDAY NIGHT OR SATURDAY NIGHT. THIS IS THE BEST CHANCE FOR SNOW
IN THE PLAINS DURING THE EXTENDED PERIOD...THOUGH THE MODELS WILL
HAVE CHANCES FOR OROGRAPHIC SHOWERS AS THE FLOW ALOFT CONTINUES TO
BE FAIRLY MOIST.
TEMPERATURES WEDNESDAY THROUGH FRIDAY ARE GOING TO BE GOVERNED BY
A COUPLE OF FACTORS. DOWNSLOPE WINDS WILL BE FAVORED ACROSS THE
WESTERN AND CENTRAL ZONES BUT AIR WEST OF THE DIVIDE IS SO COLD
THAT THE WARMUP WILL BE MUCH SLOWER THAN NORMAL FOEHN WINDS WOULD
CREATE. ALSO...SNOW COVER WILL REGULATE A PART OF THE WARMUP AND
THE POSITION OF THE SURFACE TROUGH WILL SHOW THE EASTWARD EXTENT
OF THE BEST WARMING WITH TEMPERATURES STAYING COOLER EAST OF THE
TROUGH. BY THE WEEKEND THE PUSH WESTWARD OF THE COLD FRONT WILL
SUPPORT A DROP OF TEMPERATURES BUT AGAIN HOW FAR WEST AND HOW
DRAMATIC IS STILL NOT CERTAIN. WITH COLDER AIR POOLED UP WEST OF
THE DIVIDE WIND IS GOING TO BE A OMNIPRESENT FEATURE FOR THE
WESTERN ZONES. BORSUM
&&
.AVIATION...
FAST MOVING COLD FRONT WILL MOVE THROUGH EASTERN AND CENTRAL
MONTANA BRINGING INCREASED WINDS...BLOWING SNOW AND SNOW SHOWERS.
BEST CHANCE FOR SNOW WILL BE FOR EASTERN MONTANA WITH BLOWING SNOW
BEING THE BIGGEST PROBLEM FOR KBIL AND KLVM. VERY STRONG WINDS ARE
POSSIBLE FOR KLVM WITH DRIFTING AND BLOWING SNOW CREATING IFR
CONDITIONS AT TIMES. KBIL WILL SEE WINDS GUSTS TO 45 MPH WITH MVFR
CONDITIONS DUE TO BLOWING SNOW. KMLS WILL SEE LOWER CEILINGS IN
THE SNOW SHOWERS WITH IFR CONDITIONS AT TIMES. KSHR WILL SEE
CONDITIONS STAY MOSTLY VFR BUT WILL APPROACH MVFR CONDITIONS LATER
IN THE AFTERNOON. BORSUM
&&
.PRELIMINARY POINT TEMP/POPS...
TDY TUE WED THU FRI SAT SUN
-------------------------------------------------------
BIL 019 014/023 005/029 020/033 018/034 015/034 024/036
1/Q 16/S 51/B 11/B 11/B 11/B 11/B
LVM 016 010/022 007/026 020/032 021/034 019/032 024/033
2/J 24/S 42/J 11/N 12/J 11/B 11/N
HDN 022 012/022 901/027 014/035 015/032 012/032 022/036
2/J 28/S 51/B 11/B 11/E 11/B 12/B
MLS 020 009/016 907/023 010/031 013/026 010/028 020/035
9/J 38/S 21/B 11/B 12/J 11/B 22/B
4BQ 020 011/020 903/022 011/034 017/031 012/032 023/036
8/J 47/S 21/B 00/B 01/B 11/B 22/B
BHK 016 009/013 910/017 009/029 012/022 010/027 018/033
9/J 56/S 11/B 01/B 11/B 11/E 12/B
SHR 023 008/024 901/027 014/036 016/034 014/033 022/038
2/J 25/S 51/B 01/B 12/J 11/B 11/B
&&
.BYZ WATCHES/WARNINGS/ADVISORIES...
MT...WINTER WEATHER ADVISORY IN EFFECT UNTIL 5 AM MST TUESDAY FOR
ZONES 28-29-34-35-39-41-42-56-63-65-66.
WINTER WEATHER ADVISORY IN EFFECT UNTIL 11 PM MST THIS
EVENING FOR ZONES 30>33-36>38-57-58.
WY...NONE.
&&
$$
WEATHER.GOV/BILLINGS
AREA FORECAST DISCUSSION
NWS BILLINGS MT
916 AM MST MON DEC 9 2013
.UPDATE...
NO CHANGES MADE TO INHERITED FORECAST. THE SHORT TERM FORECAST
APPEARS IN GOOD SHAPE...WITH STRONG AND GUSTY WINDS IMPACTING
AREAS FROM BILLINGS TO THE WEST. STRONGEST WINDS ARE IN BIG TIMBER
AND LIVINGSTON...WHERE GUSTS ARE APPROACHING 60 MPH AND ARE
EXPECTED TO INCREASE INTO THIS AFTERNOON. VISIBILITIES HAVE BEEN
REDUCED TO LESS THAN A QUARTER MILE IN BIG TIMBER AND TO AROUND 1
MILE IN LIVINGSTON...WITH LOCALIZED WHITE OUT CONDITIONS. THESE
LOCALIZED WHITE OUT CONDITIONS ARE EXPECTED TO CONTINUE THROUGH
TODAY...AND POSSIBLY INTO TONIGHT.
ADDITIONALLY...SLIDE OFFS HAVE BEEN REPORTED IN SEVERAL LOCATIONS
INCLUDING MUSSELSHELL...STILLWATER...AND SWEET GRASS COUNTIES.
BLOWING AND DRIFTING SNOW MAY HAVE BEEN A CONTRIBUTING FACTOR IN
CONJUNCTION WITH ALREADY ICY ROADWAYS. AAG
&&
.SHORT TERM...VALID FOR TDY AND TUE...
WIND-RELATED WINTER WEATHER ISSUES TODAY WILL TRANSITION BACK TO A
HIGH PROBABILITY OF 1 TO 2 INCHES OF SNOW IN MANY AREAS TUE AS TWO
SHORT WAVES CROSS THE REGION IN STRONG NORTHWEST FLOW ALOFT. WE DO
STILL EXPECT A SLOW MODERATION IN TEMPERATURES TO CONTINUE THOUGH.
TODAY...LEE-SIDE SURFACE PRESSURE FALLS ON THE ORDER OF 5 HPA/3 HR
CENTERED ACROSS THE CENTRAL ALBERTA-SASKATCHEWAN BORDER EARLY THIS
MORNING WILL REACH NORTHEAST MT AND WESTERN ND BY MIDDAY. THE WIND
SPEEDS IN SOUTH CENTRAL MT WILL CONTINUE RAMPING UP AS THAT OCCURS
AND WILL BE BOOSTED FURTHER BY EXTRA PRESSURE GRADIENT THANKS TO A
FORMIDABLE COLD AIR MASS TRAPPED WEST OF THE LOCAL MOUNTAINS. WIND
SPEEDS IN THE GRIDDED FORECAST WERE HEAVILY WEIGHTED TO RAP OUTPUT
SINCE IT IS HANDLING EARLY-DAY WINDS NEAR BIG TIMBER /WHICH IS THE
FAVORED SPOT FOR THE HIGHEST SPEEDS IN THIS PATTERN/ WELL. WE THUS
HAVE HIGH CONFIDENCE IN SUSTAINED SPEEDS OF 40 TO 50 MPH AND GUSTS
TO 70 MPH FROM LIVINGSTON TO BIG TIMBER TODAY...AND GUSTS UP TO 55
MPH AT HARLOWTON AND 45 MPH AROUND BILLINGS TOO. THE WINDS WILL BE
ON THE INCREASE ON THE PLAINS OF SOUTH CENTRAL AND SOUTHEAST MT BY
21 UTC AS WELL AS MIXING INCREASES AND A MODEST BATCH OF LOW-LEVEL
HEIGHT RISES BEGINS AFFECTING THAT AREA...THOUGH MOMENTUM TRANSFER
WILL BE LACKING AND ONLY SUPPORTS GUSTS TO ABOUT 35 MPH ACROSS THE
SOUTHEAST PART OF MT. ADD IN SNOW SHOWERS WHICH COULD DROP A QUICK
INCH OF SNOW AND REDUCE VISIBILITY ON THEIR OWN TOO OVER SOUTHEAST
MT THOUGH...AND CONDITIONS COULD BE QUITE HAZARDOUS OVER THAT AREA
AS WELL. WE ACTUALLY PUSHED POPS FOR SNOW SHOWER ACTIVITY INTO THE
70-90 PERCENT RANGE OVER SOUTHEAST MT THIS AFTERNOON BASED ON GOOD
AGREEMENT IN 00 UTC GUIDANCE IN NOTABLE QG-FORCING OVER THAT AREA.
NEEDLESS TO SAY...BLOWING AND DRIFTING SNOW IS MENTIONED TODAY AND
INTO THIS EVENING FOR MOST OF THE AREA...THOUGH DEPTH AND PHYSICAL
CHARACTERISTICS OF THE SNOW SUGGEST THE BIGGEST ISSUE COULD END UP
BEING SIGNIFICANT DRIFTING. WE WILL NONETHELESS NEED TO BE WARY OF
THE POSSIBILITY OF BONAFIDE GROUND BLIZZARD CONDITIONS IN THE OPEN
COUNTRY WHERE LOCALLY DEEPER SNOW PACK RESIDES...THOUGH THE CHANCE
OF THAT APPEARS RELATIVELY LOW /SUBJECTIVELY NEAR 30 PERCENT/.
WHERE HEADLINES ARE CONCERNED...WE ADDED ALL OF BIG HORN COUNTY TO
A WINTER WEATHER ADVISORY FROM 18 TO 06 UTC SINCE OUR RAP-WEIGHTED
WIND FORECAST SUPPORTED SPEEDS SUFFICIENT FOR BLOWING AND DRIFTING
SNOW ISSUES THERE TOO. THE REST OF OUR PREVIOUSLY-ISSUED HEADLINES
WERE LEFT IN TACT. WE WILL PROBABLY HIT HIGH WIND CRITERIA FOR THE
SUSTAINED 50 MPH SPEEDS AT BIG TIMBER TODAY...BUT FELT IT WAS BEST
TO COVER THIS WITH ONE PRODUCT...THE WINTER WEATHER ADVISORY. NOTE
THAT IF WINDS IN SOUTH CENTRAL MT /NAMELY IN THE LIVINGSTON TO BIG
TIMBER CORRIDOR/ STAY UP PAST 12 UTC TUE MORNING AS SOME OF THE 00
UTC GUIDANCE SHOWS...PARTS OF THE ADVISORY MAY NEED TO BE EXTENDED
IN TIME WITH A LATER FORECAST RELEASE.
TONIGHT...THE SHORT WAVE WILL EXIT THE AREA...AND WINDS WILL BE ON
A DOWNWARD TREND /ESPECIALLY AFTER 06 UTC/...EVEN THOUGH THEY WILL
STAY GUSTY IN SOUTH CENTRAL MT. WE CAUTIOUSLY FOLLOWED THE LEAD OF
RECENTLY WELL-PERFORMING GUIDANCE THAT SHOWS LOWS ONLY AROUND 10 F
/MUCH WARMER THAN RECENT NIGHTS/ GIVEN EXPECTED LOW-LEVEL MIXING.
TUE...A LIGHT SNOW EVENT IS EXPECTED IN MANY AREAS AS A GOOD BATCH
OF QG-FORCING WITH ANOTHER SHORT WAVE TROUGH RIDES SOUTHEAST ALONG
THE THERMAL BOUNDARY LEFT BEHIND TODAY/S WAVE. IT LOOKS LIKE WINDS
WILL EVEN TURN NORTH OR NORTHEAST IN BILLINGS BY AFTERNOON...SO WE
WILL PROBABLY GET IN ON SOME LIGHT SNOW HERE TOO. WE HAD ENOUGH IN
THE WAY OF CONFIDENCE IN THIS WHOLE SCENARIO TO SIGNIFICANTLY RAMP
UP POPS IN MANY AREAS...GOING AS FAR AS 80 PERCENT FROM MILES CITY
TO HYSHAM AND DOWN TOWARD LAME DEER AND LODGE GRASS. THIS LOOKS TO
BE A GOOD 1 TO 2 INCH SNOW EVENT IN MANY AREAS. SCHULTZ
.LONG TERM...VALID FOR WED...THU...FRI...SAT...SUN...
NORTHWEST FLOW ALOFT ON WEDNESDAY SLOWLY BECOMES A MORE WESTERLY
FLOW ON THURSDAY WHICH WILL ALLOW A LEESIDE SURFACE PRESSURE
TROUGH TO BE THE DOMINANT FEATURE EAST OF THE CONTINENTAL DIVIDE.
THIS PATTERN HOLDS UNTIL LATER ON FRIDAY WHEN AN UPPER LEVEL RIDGE
BUILDING INTO THE PACIFIC NORTHWEST TURNS THE FLOW NORTHWESTERLY
OVER MONTANA AND WYOMING. AT SOME POINT COLDER AIR OVER THE
DAKOTAS WILL HAVE A CHANCE TO PUSH A BACKDOOR COLD FRONT INTO
SOUTHERN MONTANA BUT WHEN IS NOT EXACTLY SURE...WHETHER IT WILL BE
FRIDAY NIGHT OR SATURDAY NIGHT. THIS IS THE BEST CHANCE FOR SNOW
IN THE PLAINS DURING THE EXTENDED PERIOD...THOUGH THE MODELS WILL
HAVE CHANCES FOR OROGRAPHIC SHOWERS AS THE FLOW ALOFT CONTINUES TO
BE FAIRLY MOIST.
TEMPERATURES WEDNESDAY THROUGH FRIDAY ARE GOING TO BE GOVERNED BY
A COUPLE OF FACTORS. DOWNSLOPE WINDS WILL BE FAVORED ACROSS THE
WESTERN AND CENTRAL ZONES BUT AIR WEST OF THE DIVIDE IS SO COLD
THAT THE WARMUP WILL BE MUCH SLOWER THAN NORMAL FOEHN WINDS WOULD
CREATE. ALSO...SNOW COVER WILL REGULATE A PART OF THE WARMUP AND
THE POSITION OF THE SURFACE TROUGH WILL SHOW THE EASTWARD EXTENT
OF THE BEST WARMING WITH TEMPERATURES STAYING COOLER EAST OF THE
TROUGH. BY THE WEEKEND THE PUSH WESTWARD OF THE COLD FRONT WILL
SUPPORT A DROP OF TEMPERATURES BUT AGAIN HOW FAR WEST AND HOW
DRAMATIC IS STILL NOT CERTAIN. WITH COLDER AIR POOLED UP WEST OF
THE DIVIDE WIND IS GOING TO BE A OMNIPRESENT FEATURE FOR THE
WESTERN ZONES. BORSUM
&&
.AVIATION...
FAST MOVING COLD FRONT WILL MOVE THROUGH EASTERN AND CENTRAL
MONTANA BRINGING INCREASED WINDS...BLOWING SNOW AND SNOW SHOWERS.
BEST CHANCE FOR SNOW WILL BE FOR EASTERN MONTANA WITH BLOWING SNOW
BEING THE BIGGEST PROBLEM FOR KBIL AND KLVM. VERY STRONG WINDS ARE
POSSIBLE FOR KLVM WITH DRIFTING AND BLOWING SNOW CREATING IFR
CONDITIONS AT TIMES. KBIL WILL SEE WINDS GUSTS TO 45 MPH WITH MVFR
CONDITIONS DUE TO BLOWING SNOW. KMLS WILL SEE LOWER CEILINGS IN
THE SNOW SHOWERS WITH IFR CONDITIONS AT TIMES. KSHR WILL SEE
CONDITIONS STAY MOSTLY VFR BUT WILL APPROACH MVFR CONDITIONS LATER
IN THE AFTERNOON. BORSUM
&&
.PRELIMINARY POINT TEMP/POPS...
TDY TUE WED THU FRI SAT SUN
-------------------------------------------------------
BIL 019 014/023 005/029 020/033 018/034 015/034 024/036
1/Q 16/S 51/B 11/B 11/B 11/B 11/B
LVM 016 010/022 007/026 020/032 021/034 019/032 024/033
2/J 24/S 42/J 11/N 12/J 11/B 11/N
HDN 022 012/022 901/027 014/035 015/032 012/032 022/036
2/J 28/S 51/B 11/B 11/E 11/B 12/B
MLS 020 009/016 907/023 010/031 013/026 010/028 020/035
9/J 38/S 21/B 11/B 12/J 11/B 22/B
4BQ 020 011/020 903/022 011/034 017/031 012/032 023/036
8/J 47/S 21/B 00/B 01/B 11/B 22/B
BHK 016 009/013 910/017 009/029 012/022 010/027 018/033
9/J 56/S 11/B 01/B 11/B 11/E 12/B
SHR 023 008/024 901/027 014/036 016/034 014/033 022/038
2/J 25/S 51/B 01/B 12/J 11/B 11/B
&&
.BYZ WATCHES/WARNINGS/ADVISORIES...
MT...WINTER WEATHER ADVISORY IN EFFECT UNTIL 5 AM MST TUESDAY FOR
ZONES 28-29-34-35-39-41-42-56-63-65-66.
WIND CHILL ADVISORY IN EFFECT UNTIL 11 AM MST THIS MORNING
FOR ZONES 30>33-36>38-57-58.
WINTER WEATHER ADVISORY IN EFFECT UNTIL 11 PM MST THIS
EVENING FOR ZONES 30>33-36>38-57-58.
WY...NONE.
&&
$$
WEATHER.GOV/BILLINGS
AREA FORECAST DISCUSSION
NWS BILLINGS MT
331 AM MST MON DEC 9 2013
.SHORT TERM...VALID FOR TDY AND TUE...
WIND-RELATED WINTER WEATHER ISSUES TODAY WILL TRANSITION BACK TO A
HIGH PROBABILITY OF 1 TO 2 INCHES OF SNOW IN MANY AREAS TUE AS TWO
SHORT WAVES CROSS THE REGION IN STRONG NORTHWEST FLOW ALOFT. WE DO
STILL EXPECT A SLOW MODERATION IN TEMPERATURES TO CONTINUE THOUGH.
TODAY...LEE-SIDE SURFACE PRESSURE FALLS ON THE ORDER OF 5 HPA/3 HR
CENTERED ACROSS THE CENTRAL ALBERTA-SASKATCHEWAN BORDER EARLY THIS
MORNING WILL REACH NORTHEAST MT AND WESTERN ND BY MIDDAY. THE WIND
SPEEDS IN SOUTH CENTRAL MT WILL CONTINUE RAMPING UP AS THAT OCCURS
AND WILL BE BOOSTED FURTHER BY EXTRA PRESSURE GRADIENT THANKS TO A
FORMIDABLE COLD AIR MASS TRAPPED WEST OF THE LOCAL MOUNTAINS. WIND
SPEEDS IN THE GRIDDED FORECAST WERE HEAVILY WEIGHTED TO RAP OUTPUT
SINCE IT IS HANDLING EARLY-DAY WINDS NEAR BIG TIMBER /WHICH IS THE
FAVORED SPOT FOR THE HIGHEST SPEEDS IN THIS PATTERN/ WELL. WE THUS
HAVE HIGH CONFIDENCE IN SUSTAINED SPEEDS OF 40 TO 50 MPH AND GUSTS
TO 70 MPH FROM LIVINGSTON TO BIG TIMBER TODAY...AND GUSTS UP TO 55
MPH AT HARLOWTON AND 45 MPH AROUND BILLINGS TOO. THE WINDS WILL BE
ON THE INCREASE ON THE PLAINS OF SOUTH CENTRAL AND SOUTHEAST MT BY
21 UTC AS WELL AS MIXING INCREASES AND A MODEST BATCH OF LOW-LEVEL
HEIGHT RISES BEGINS AFFECTING THAT AREA...THOUGH MOMENTUM TRANSFER
WILL BE LACKING AND ONLY SUPPORTS GUSTS TO ABOUT 35 MPH ACROSS THE
SOUTHEAST PART OF MT. ADD IN SNOW SHOWERS WHICH COULD DROP A QUICK
INCH OF SNOW AND REDUCE VISIBILITY ON THEIR OWN TOO OVER SOUTHEAST
MT THOUGH...AND CONDITIONS COULD BE QUITE HAZARDOUS OVER THAT AREA
AS WELL. WE ACTUALLY PUSHED POPS FOR SNOW SHOWER ACTIVITY INTO THE
70-90 PERCENT RANGE OVER SOUTHEAST MT THIS AFTERNOON BASED ON GOOD
AGREEMENT IN 00 UTC GUIDANCE IN NOTABLE QG-FORCING OVER THAT AREA.
NEEDLESS TO SAY...BLOWING AND DRIFTING SNOW IS MENTIONED TODAY AND
INTO THIS EVENING FOR MOST OF THE AREA...THOUGH DEPTH AND PHYSICAL
CHARACTERISTICS OF THE SNOW SUGGEST THE BIGGEST ISSUE COULD END UP
BEING SIGNIFICANT DRIFTING. WE WILL NONETHELESS NEED TO BE WARY OF
THE POSSIBILITY OF BONAFIDE GROUND BLIZZARD CONDITIONS IN THE OPEN
COUNTRY WHERE LOCALLY DEEPER SNOW PACK RESIDES...THOUGH THE CHANCE
OF THAT APPEARS RELATIVELY LOW /SUBJECTIVELY NEAR 30 PERCENT/.
WHERE HEADLINES ARE CONCERNED...WE ADDED ALL OF BIG HORN COUNTY TO
A WINTER WEATHER ADVISORY FROM 18 TO 06 UTC SINCE OUR RAP-WEIGHTED
WIND FORECAST SUPPORTED SPEEDS SUFFICIENT FOR BLOWING AND DRIFTING
SNOW ISSUES THERE TOO. THE REST OF OUR PREVIOUSLY-ISSUED HEADLINES
WERE LEFT IN TACT. WE WILL PROBABLY HIT HIGH WIND CRITERIA FOR THE
SUSTAINED 50 MPH SPEEDS AT BIG TIMBER TODAY...BUT FELT IT WAS BEST
TO COVER THIS WITH ONE PRODUCT...THE WINTER WEATHER ADVISORY. NOTE
THAT IF WINDS IN SOUTH CENTRAL MT /NAMELY IN THE LIVINGSTON TO BIG
TIMBER CORRIDOR/ STAY UP PAST 12 UTC TUE MORNING AS SOME OF THE 00
UTC GUIDANCE SHOWS...PARTS OF THE ADVISORY MAY NEED TO BE EXTENDED
IN TIME WITH A LATER FORECAST RELEASE.
TONIGHT...THE SHORT WAVE WILL EXIT THE AREA...AND WINDS WILL BE ON
A DOWNWARD TREND /ESPECIALLY AFTER 06 UTC/...EVEN THOUGH THEY WILL
STAY GUSTY IN SOUTH CENTRAL MT. WE CAUTIOUSLY FOLLOWED THE LEAD OF
RECENTLY WELL-PERFORMING GUIDANCE THAT SHOWS LOWS ONLY AROUND 10 F
/MUCH WARMER THAN RECENT NIGHTS/ GIVEN EXPECTED LOW-LEVEL MIXING.
TUE...A LIGHT SNOW EVENT IS EXPECTED IN MANY AREAS AS A GOOD BATCH
OF QG-FORCING WITH ANOTHER SHORT WAVE TROUGH RIDES SOUTHEAST ALONG
THE THERMAL BOUNDARY LEFT BEHIND TODAY/S WAVE. IT LOOKS LIKE WINDS
WILL EVEN TURN NORTH OR NORTHEAST IN BILLINGS BY AFTERNOON...SO WE
WILL PROBABLY GET IN ON SOME LIGHT SNOW HERE TOO. WE HAD ENOUGH IN
THE WAY OF CONFIDENCE IN THIS WHOLE SCENARIO TO SIGNIFICANTLY RAMP
UP POPS IN MANY AREAS...GOING AS FAR AS 80 PERCENT FROM MILES CITY
TO HYSHAM AND DOWN TOWARD LAME DEER AND LODGE GRASS. THIS LOOKS TO
BE A GOOD 1 TO 2 INCH SNOW EVENT IN MANY AREAS. SCHULTZ
.LONG TERM...VALID FOR WED...THU...FRI...SAT...SUN...
NORTHWEST FLOW ALOFT ON WEDNESDAY SLOWLY BECOMES A MORE WESTERLY
FLOW ON THURSDAY WHICH WILL ALLOW A LEESIDE SURFACE PRESSURE
TROUGH TO BE THE DOMINANT FEATURE EAST OF THE CONTINENTAL DIVIDE.
THIS PATTERN HOLDS UNTIL LATER ON FRIDAY WHEN AN UPPER LEVEL RIDGE
BUILDING INTO THE PACIFIC NORTHWEST TURNS THE FLOW NORTHWESTERLY
OVER MONTANA AND WYOMING. AT SOME POINT COLDER AIR OVER THE
DAKOTAS WILL HAVE A CHANCE TO PUSH A BACKDOOR COLD FRONT INTO
SOUTHERN MONTANA BUT WHEN IS NOT EXACTLY SURE...WHETHER IT WILL BE
FRIDAY NIGHT OR SATURDAY NIGHT. THIS IS THE BEST CHANCE FOR SNOW
IN THE PLAINS DURING THE EXTENDED PERIOD...THOUGH THE MODELS WILL
HAVE CHANCES FOR OROGRAPHIC SHOWERS AS THE FLOW ALOFT CONTINUES TO
BE FAIRLY MOIST.
TEMPERATURES WEDNESDAY THROUGH FRIDAY ARE GOING TO BE GOVERNED BY
A COUPLE OF FACTORS. DOWNSLOPE WINDS WILL BE FAVORED ACROSS THE
WESTERN AND CENTRAL ZONES BUT AIR WEST OF THE DIVIDE IS SO COLD
THAT THE WARMUP WILL BE MUCH SLOWER THAN NORMAL FOEHN WINDS WOULD
CREATE. ALSO...SNOW COVER WILL REGULATE A PART OF THE WARMUP AND
THE POSITION OF THE SURFACE TROUGH WILL SHOW THE EASTWARD EXTENT
OF THE BEST WARMING WITH TEMPERATURES STAYING COOLER EAST OF THE
TROUGH. BY THE WEEKEND THE PUSH WESTWARD OF THE COLD FRONT WILL
SUPPORT A DROP OF TEMPERATURES BUT AGAIN HOW FAR WEST AND HOW
DRAMATIC IS STILL NOT CERTAIN. WITH COLDER AIR POOLED UP WEST OF
THE DIVIDE WIND IS GOING TO BE A OMNIPRESENT FEATURE FOR THE
WESTERN ZONES. BORSUM
&&
.AVIATION...
FAST MOVING COLD FRONT WILL MOVE THROUGH EASTERN AND CENTRAL
MONTANA BRINGING INCREASED WINDS...BLOWING SNOW AND SNOW SHOWERS.
BEST CHANCE FOR SNOW WILL BE FOR EASTERN MONTANA WITH BLOWING SNOW
BEING THE BIGGEST PROBLEM FOR KBIL AND KLVM. VERY STRONG WINDS ARE
POSSIBLE FOR KLVM WITH DRIFTING AND BLOWING SNOW CREATING IFR
CONDITIONS AT TIMES. KBIL WILL SEE WINDS GUSTS TO 45 MPH WITH MVFR
CONDITIONS DUE TO BLOWING SNOW. KMLS WILL SEE LOWER CEILINGS IN
THE SNOW SHOWERS WITH IFR CONDITIONS AT TIMES. KSHR WILL SEE
CONDITIONS STAY MOSTLY VFR BUT WILL APPROACH MVFR CONDITIONS LATER
IN THE AFTERNOON. BORSUM
&&
.PRELIMINARY POINT TEMP/POPS...
TDY TUE WED THU FRI SAT SUN
-------------------------------------------------------
BIL 019 014/023 005/029 020/033 018/034 015/034 024/036
1/Q 16/S 51/B 11/B 11/B 11/B 11/B
LVM 016 010/022 007/026 020/032 021/034 019/032 024/033
2/J 24/S 42/J 11/N 12/J 11/B 11/N
HDN 022 012/022 901/027 014/035 015/032 012/032 022/036
2/J 28/S 51/B 11/B 11/E 11/B 12/B
MLS 020 009/016 907/023 010/031 013/026 010/028 020/035
9/J 38/S 21/B 11/B 12/J 11/B 22/B
4BQ 020 011/020 903/022 011/034 017/031 012/032 023/036
8/J 47/S 21/B 00/B 01/B 11/B 22/B
BHK 016 009/013 910/017 009/029 012/022 010/027 018/033
9/J 56/S 11/B 01/B 11/B 11/E 12/B
SHR 023 008/024 901/027 014/036 016/034 014/033 022/038
2/J 25/S 51/B 01/B 12/J 11/B 11/B
&&
.BYZ WATCHES/WARNINGS/ADVISORIES...
MT...WINTER WEATHER ADVISORY IN EFFECT UNTIL 5 AM MST TUESDAY FOR
ZONES 28-29-34-35-39-41-42-56-63-65-66.
WIND CHILL ADVISORY IN EFFECT UNTIL 11 AM MST THIS MORNING
FOR ZONES 30>33-36>38-57-58.
WINTER WEATHER ADVISORY IN EFFECT FROM 11 AM THIS MORNING TO
11 PM MST THIS EVENING FOR ZONES 30>33-36>38-57-58.
WY...NONE.
&&
$$
WEATHER.GOV/BILLINGS
AREA FORECAST DISCUSSION...UPDATED
NWS NORTH PLATTE NE
626 PM CST TUE DEC 10 2013
.SYNOPSIS...
ISSUED AT 305 PM CST TUE DEC 10 2013
H5 ANALYSIS THIS MORNING HAS BROAD NORTHWESTERLY FLOW
ACROSS THE WESTERN HALF OF THE CONUS WITH DEEP LOW PRESSURE OVER SRN
HUDSON BAY. AT THE SURFACE...A COLD FRONT EXTENDED FROM NERN WYOMING
INTO NERN SD. FURTHER SOUTH ACROSS WESTERN AND NORTH CENTRAL
NEBRASKA...WESTERLY FLOW HAS DEVELOPED THIS AFTERNOON WITH
TEMPERATURES REACHING THE 20S AND LOWER 30S.
&&
.UPDATE...
ISSUED AT 614 PM CST TUE DEC 10 2013
THE ECM...RAP...GEM REG AND HRRR MODELS SHOW WIND CHILL ADVISORY
CONDITIONS BY MORNING ACROSS THE NORTHEAST FROM AINWSORTH AND
ONEILL NORTH. A NEW FORECAST IS OUT FOR THESE CONDITIONS.
OTHERWISE THE REST OF THE FORECAST IS ON TRACK WITH THE LEADING
EDGE OF THE ARCTIC AIR ENTERING SHERIDAN COUNTY AND SETTING OFF
SNOW SHOWERS. LOW LEVEL LAPSE RATES ARE VERY STEEP WITH ECHO TOPS
LESS THAN 10KFT.
&&
.SHORT TERM...(THIS EVENING THROUGH WEDNESDAY)
ISSUED AT 305 PM CST TUE DEC 10 2013
AN ARCTIC COLD FRONT WILL MOVE SOUTHEAST ACROSS THE AREA
TONIGHT...WITH A FEW SNOW SHOWERS POSSIBLE ACROSS NORTHERN NEBRASKA
BEHIND THE FRONT. FLURRIES ARE POSSIBLE FARTHER SOUTH AS
WELL...WITH A PERIOD OF WEAK LIFT THROUGH A SATURATED DENDRITIC
LAYER BEHIND THE FRONT. OTHERWISE...WINDS DIMINISH AS HIGH PRESSURE
SETTLES INTO NORTHERN NEBRASKA LATE TONIGHT. THIS WILL ALLOW FOR
LOWS TO DROP TO NEAR ZERO OR JUST BELOW AS SKIES CLEAR LATE.
FARTHER SOUTH WINDS REMAIN UP THROUGH THE NIGHT...AND THIS WILL
HELP KEEP LOWS SOMEWHAT WARMER.
HIGH PRESSURE WILL QUICKLY MOVE SOUTHEAST OF THE AREA
WEDNESDAY...WITH WARMING SOUTHWEST WINDS DEVELOPING BY WEDNESDAY
AFTERNOON. HAVE PUSHED HIGHS UP INTO THE LOWER 30S ACROSS
SOUTHWEST NEBRASKA...BUT ONLY NEAR 20 DEGREES ACROSS EASTERN
PORTIONS OF NORTH CENTRAL NEBRASKA WHERE THE ARCTIC AIR WILL BE
DEEPER.
.LONG TERM...(WEDNESDAY NIGHT THROUGH TUESDAY)
ISSUED AT 305 PM CST TUE DEC 10 2013
IN THE MID
RANGE...TEMPERATURES ARE THE MAIN FORECAST CHALLENGE. FOR WEDNESDAY
NIGHT...LOOK FOR WINDS TO DECREASE BY LATE EVENING AS A WARM FRONT
TRACKS EAST OF THE AREA. CLEAR SKIES AND LIGHT WINDS WILL ALLOW
TEMPS TO DIP INTO THE SINGLE DIGITS ACROSS THE FORECAST AREA.
INHERITED FORECAST HAD ALOT OF TEENS FOR LOWS WEDS NIGHT AND SCALED
THESE BACK TOWARD THE NEW GUIDANCE...WHICH TRENDED MUCH LOWER AS
WELL. ON THURSDAY...WARMER PACIFIC AIR WILL PUSH INTO THE CENTRAL
PLAINS WITH H85 TEMPS REACHING THE MIDDLE SINGLE DIGITS CELSIUS
ABOVE ZERO THURSDAY AFTERNOON. NORMALLY WITH GOOD MIXING...HIGHS
WOULD REACH THE UPPER 40S TO LOWER 50S. HOWEVER...WINDS ARE EXPECTED
TO BE FAIRLY LIGHT THURSDAY...A BY PRODUCT OF SNOW COVER AND ITS
IMPACT ON MIXING. BUFKIT SOUNDINGS FOR BOTH LBF AND VTN ARE NOT
INDICATIVE OF MIXING EITHER. GUIDANCE HIGHS THURSDAY FOR VALENTINE
WERE IN THE MID 40S WITH THIS MORNINGS FCST. THIS SEEMS WAY TOO HIGH
WITH 6+ INCHES OF SNOW EXPECTED TO BE ON THE GROUND ACROSS NORTH
CENTRAL NEBRASKA. HAVE OPTED FOR HIGH IN THE LOWER 40S SOUTHWEST TO
LOWER 30S IN THE NORTHEAST AND PORTIONS OF THE NORTH CENTRAL
FORECAST AREA. LOWS THURSDAY NIGHT WILL BE SLIGHTLY HIGHER THAN
WEDNESDAY NIGHTS MIN TEMPS DUE TO INCREASED HIGH LEVEL
CLOUDINESS...AND THE DEVELOPMENT OF LIGHT WINDS IN ADVANCE OF THE
NEXT ARCTIC COLD FRONT WHICH WILL ARRIVE SOMETIME FRIDAY MORNING OR
AFTERNOON. I DID GO AHEAD AND TREND DOWN HIGHS FRIDAY ACROSS THE
NORTHERN CWA BASED ON A SLIGHTLY FASTER FRONTAL TIMING IE. GFS
SOLUTION...WHICH HAS BEEN MORE CONSISTENT. HIGHS FRIDAY WILL RANGE
FROM THE MID 20S IN THE NORTHEAST...TO AROUND 40 IN THE
SOUTHWEST.
FRIDAY NIGHT THROUGH TUESDAY...BROAD NORTHWESTERLY FLOW WILL
CONTINUE ACROSS THE CENTRAL AND NORTHERN PLAINS FOR THE EXTENDED
PERIOD. WITH THE NORTHWESTERLY FLOW IN PLACE ARCTIC COLD AIR WILL
BACK INTO THE FORECAST AREA SATURDAY...RETREATING EASTWARD LATE
SUNDAY OR MONDAY. ATTM...THE GFS AND ECMWF SOLUTIONS ARE AT ODDS
WITH HOW FAST THE FRONT PUSHES EAST OUT OF THE AREA WITH THE GFS
BEING SLOWER. ON MONDAY INTO TUESDAY...THE GFS ADVERTISES A NICE
WARMUP WHILE THE ECMWF USHERS IN ANOTHER SHOT OF ARCTIC AIR. FOR
NOW...WILL COMPROMISE BETWEEN SOLUTIONS AND LEAVE THE FORECAST DRY
AS THE NORTHWESTERLY FLOW FAVORS IT.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z WEDNESDAY EVENING)
ISSUED AT 515 PM CST TUE DEC 10 2013
AN ARCTIC COLD FRONT...CURRENTLY APPROACHING KIEN...KICR AND
K9V9...WILL MOVE THROUGH THE FCST AREA TONIGHT AND THEN RETREAT
EAST WEDNESDAY AFTERNOON AS A WARM FRONT.
THE ARCTIC FRONT IS EXPECTED TO PRODUCE AREAS OF MVFR AND LOCAL
IFR/LOCAL LIFR IN SCATTERED SNOW SHOWERS AND SQUALLS AS IT MOVES
THROUGH TONIGHT. FLIGHT CONDITIONS ARE EXPECTED TO IMPROVE TO VFR
AROUND 14Z AS SFC WINDS BECOME WEST AND SOUTHWEST.
&&
.LBF WATCHES/WARNINGS/ADVISORIES...
WIND CHILL ADVISORY FROM 2 AM TO 11 AM CST WEDNESDAY FOR
NEZ006>010.
&&
$$
UPDATE...CDC
SYNOPSIS...CLB
SHORT TERM...TAYLOR
LONG TERM...CLB
AVIATION...CDC
AREA FORECAST DISCUSSION
NWS OMAHA/VALLEY NE
518 PM CST TUE DEC 10 2013
.AVIATION...00Z TAFS FOR KOFK...KLNK AND KOMA.
GENERALLY VFR CONDITIONS ARE EXPECTED THROUGH WEDNESDAY AFTERNOON.
A LOW PRESSURE SYSTEM RACING SOUTHEAST INTO IOWA WILL DRAG A COLD
FRONT THROUGH EASTERN NEBRASKA THIS EVENING. LIGHT SNOW AND MVFR
CIGS ARE POSSIBLE WITH THE FRONT...BUT THE BULK OF THIS ACTIVITY
WILL REMAIN WELL NORTHEAST OF TAF SITES. A WIND SHIFT WILL ALSO
ACCOMPANY THE FRONT WITH NORTHWEST WINDS 15 TO 20KT ARRIVING AT
KOFK BY 04Z...THEN KLNK/KOMA BY 07Z. WINDS WILL DIE DOWN AFTER 12Z
WITH DECREASING CLOUDS.
DERGAN
&&
.PREV DISCUSSION... /ISSUED 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
&&
.OAX WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
IA...NONE.
&&
$$
AREA FORECAST DISCUSSION...UPDATED
NWS NORTH PLATTE NE
1112 PM CST SUN DEC 8 2013
.SYNOPSIS...
ISSUED AT 326 PM CST SUN DEC 8 2013
H5 ANALYSIS FROM THIS MORNING HAS A HIGHLY AMPLIFIED
PATTERN ACROSS NOAM THIS MORNING WITH A RIDGE EXTENDING INTO THE
GULF OF ALASKA. A CLOSED LOW WAS OVER WESTERN PORTIONS OF THE HUDSON
BAY WITH A DEEP TROUGH OF LOW PRESSURE EXTENDING SSWD INTO THE
ROCKIES AND SWRN US. NUMEROUS EMBEDDED SHORTWAVES WERE NOTED ACROSS
THE WESTERN CONUS THIS MORNING. THE FIRST OVER SWRN WYOMING...WHICH
IS CROSSING CENTRAL COLORADO AND IS EMERGING ONTO THE FRONT RANGES
JUST SOUTH OF DENVER...PER SATELLITE AND RADAR IMAGERY. ANOTHER
SHORTWAVE WAS LOCATED OVER SWRN SASKATCHEWAN AND SRN ALBERTA...AND A
THIRD WAS NOTED OFF THE NRN CALIFORNIA COAST. AT THE SURFACE...AN
AREA OF SNOW IN ASSOCIATION WITH THE FIRST SHORTWAVE...EXTENDED FROM
AROUND LIMON COLORADO...NEWD TO FAR SOUTHWESTERN NEBRASKA. THE
HEAVIEST SNOW PER RADAR IMAGERY EXTENDED FROM NEAR LIMON COLORADO TO
NEAR IMPERIAL. THIS ACTIVITY HAS BEEN MOVING TO THE EAST NORTHEAST
AND IS EXPECTED TO REMAIN MAINLY SOUTH OF THE FORECAST AREA THIS
AFTERNOON. THE EXCEPTION IS ACROSS THE FAR SOUTHWESTERN COUNTIES
WHERE 1 TO 2 INCHES IS POSSIBLE THIS AFTERNOON. ELSEWHERE...ANY
ACCUMULATIONS ARE EXPECTED TO BE AN INCH OR LESS. AS OF 3 PM
CST...UNDER PARTLY TO MOSTLY CLOUDY SKIES...TEMPERATURES RANGED FROM
11 AT VALENTINE TO 17 AT OGALLALA.
&&
.UPDATE...
ISSUED AT 729 PM CST SUN DEC 8 2013
THE RAP AND HRRR TEMPERATURE AND WIND CHILL FORECASTS APPEAR TO BE
ON TRACK WITH KVTN SHOWING A WIND CHILL OF -26F AT 7 PM CST.
THERE ARE SOME MID CLOUDS MOVING IN FROM WY WHICH WILL LIMIT THE
AMOUNT OF TIME FOR RADIATIONAL COOLING. THUS CONDITIONS ARE NOT
FAVORABLE FOR ROCK BOTTOM LOWS BUT -10F TO -20F SHOULD DEVELOP
ALONG AND WEST OF HIGHWAY 83 TONIGHT.
TEMPS HAVE BEEN LOWERED IN THE NORTH AND A WIND CHILL WARNING IS
IN PLACE FROM VALENTINE WEST TO GORDON.
&&
.SHORT TERM...(THIS EVENING THROUGH MONDAY)
ISSUED AT 326 PM CST SUN DEC 8 2013
SHORT WAVE MOVING ACROSS THE NEB/KS BORDER...WHICH MODELS HAVE
HANDLED FAIRLY WELL. LIGHT SNOW WILL BE TAPERING TO FLURRIES ACROSS
PORTIONS OF SOUTHWEST AND CENTRAL NEBRASKA BEFORE ENDING LATER THIS
EVENING. ADDITIONAL SNOWFALL COULD REACH UP TO THREE QUARTERS OF AN
INCH...HOWEVER MOST AREAS IN THE SE CWA TO SEE A COUPLE OF TENTHS.
CLEARING SKIES ARE ALREADY SEEN ON VISIBLE SAT ACROSS THE PANHANDLE
AND NW NEB. HIGH PRESSURE WILL BEGIN TO NOSE DOWN INTO THE AREA
TONIGHT...WHICH WILL COMBINE WITH THE SNOW PACK TO ALLOW FOR GOOD
RADIATIONAL COOLING. RECENT LOWS HAVE BEEN BELOW GUIDANCE WHEN SKIES
HAVE CLEARED...SO TOOK COOLER MAV GUIDANCE AND DROPPED A COUPLE OF
DEGREES...WHICH MAYBE CONSERVATIVE FOR PORTIONS OF THE NW
CWA...WHERE MORE THAN HALF A FOOT OF SNOW REMAINS ON THE GROUND.
THIS PLACES LOWS IN THE -5 TO -15 DEGREE RANGE. NORTHWEST WINDS
MOVING IN WITH THE CLEARING...ALTHOUGH THEY WILL BE DIMINISHING. THE
COMBINATION OF LIGHT WINDS AND BITTER COLD TEMPS WILL ALLOW FOR WIND
CHILLS TO FALL INTO THE -20 TO -30 RANGE...LOCALLY LOWER ACROSS NW
ZONES. WILL GO WITH A WIND CHILL ADVISORY FOR ENTIRE CWA.
TOMORROW MODELS HOLD 850 MB TEMPS FAIRLY STEADY...AND WITH MOSTLY
SUNNY SKIES EXPECT HIGHS TO REBOUND A LITTLE WARMER THAN
TODAY...HIGHS SHOULD REBOUND INTO THE TEENS TO NEAR 20.
.LONG TERM...(MONDAY NIGHT THROUGH SUNDAY)
ISSUED AT 326 PM CST SUN DEC 8 2013
MONDAY NIGHT THROUGH WEDNESDAY...THE MAIN FORECASTING
CHALLENGES ARE TEMPERATURES...THEN LOW PRECIPITATION CHANCES FOR
TUESDAY NIGHT. ON MONDAY NIGHT...A SURFACE TROUGH OF LOW PRESSURE
WILL TRACK FROM THE CENTRAL PLAINS EAST INTO THE UPPER MIDWEST.
LIMITED CAA WILL ACCOMPANY PASSAGE OF THE TROUGH. HOWEVER...IT WILL
HELP TO KEEP THE LOW LEVEL WINDS MIXED ON MONDAY NIGHT...THUS MILDER
TEMPERATURES ARE EXPECTED. ALBEIT...LOWS WILL STILL BE COLD WITH
READINGS IN THE SINGLE DIGITS. ON TUESDAY...WESTERLY DOWNSLOPE WINDS
WILL CONTINUE INCREASE SOMEWHAT TO 10 TO 15 MPH. DECIDED TO UNDERCUT
GUIDANCE FOR HIGHS TUESDAY...BASED ON SNOW COVER AND LIMITED MIXING
POTENTIAL. THIS LED TO HIGHS MAINLY IN THE 20S...WITH SOME TEMPS
NEAR THE FREEZING MARK ACROSS THE FAR SOUTHWEST. ON TUESDAY
NIGHT...AN ARCTIC COLD FRONT WILL BACK INTO NORTHERN AND
NORTHEASTERN NEBRASKA WITH A NICE PV MAX ARRIVING OVERNIGHT. CROSS
SECTIONS ACROSS NORTHERN NEBRASKA ARE INDICATIVE OF SOME WEAK LIFT
IN THE DENDRITIC LAYER WHICH MAXES OUT AROUND 06Z WEDNESDAY. TOP
DOWN SATURATION WILL HAVE TO OCCUR WITH ANY PCPN WHICH MAY FALL...SO
WILL LIMIT POP MENTION TO SLIGHTS FOR NOW...AND KEEP POPS ACROSS THE
NRN CWA AS CROSS SECTIONS NEVER MOISTEN UP ACROSS THE SRN CWA. ON
WEDNESDAY SURFACE HIGH PRESSURE WILL BUILD INTO THE MID MISSOURI
VALLEY. WINDS WILL SHIFT TO THE SOUTHWEST DURING THE AFTERNOON
HOURS...AND WILL RECYCLE COLD AIR ACROSS THE FORECAST AREA. HIGHS
WILL BE COLD...RANGING FROM THE MIDDLE TEENS IN THE NORTHEAST...TO
THE UPPER 20S IN THE FAR SOUTHWEST.
WEDNESDAY NIGHT THROUGH SUNDAY...THE MID RANGE MODEL SOLUTIONS
CONTINUE TO INDICATE LOW AMPLITUDE WEST NORTHWESTERLY FLOW ACROSS
THE CONUS FOR THE END OF THE WEEK INTO EARLY NEXT WEEK. BOTH THE
ECMWF AND GFS SOLNS ARE TRENDING TOWARD THE DEVELOPMENT OF AN UPPER
LEVEL TROUGH EMBEDDED IN THE SRN STREAM TOWARD FRIDAY. BOTH SOLNS
LIFT THIS ENERGY SOUTH OF THE AREA...SO A DRY FORECAST CONTINUES.
AFTER TEMPERATURES TREND HIGHER FOR THURSDAY AND FRIDAY WITH HIGHS
IN THE 30S...COOLER TEMPERATURES WILL ARRIVE ON FRIDAY NIGHT AS AN
ARCTIC COLD FRONT BACKS INTO THE FORECAST AREA. HIGHS WILL BE COOLER
IN THE 20S AND LOWER 30S SATURDAY...FOLLOWED BY 30S AND LOWER 40S FOR
SUNDAY.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z MONDAY NIGHT)
ISSUED AT 1112 PM CST SUN DEC 8 2013
VFR IS EXPECTED ALL AREAS TONIGHT THROUGH MONDAY EVENING. SCATTERED
TO BROKEN COVERAGE OF MID AND HIGH LEVEL CLOUDS WILL CONTINUE
ACROSS THE FCST AREA DURING THIS PERIOD.
&&
.LBF WATCHES/WARNINGS/ADVISORIES...
WIND CHILL ADVISORY UNTIL NOON CST /11 AM MST/ MONDAY FOR NEZ007-
009-010-022>029-035>038-056>059-069>071.
WIND CHILL WARNING UNTIL NOON CST /11 AM MST/ MONDAY FOR
NEZ004>006-008-094.
&&
$$
UPDATE...CDC
SYNOPSIS...CLB
SHORT TERM...MASEK
LONG TERM...CLB
AVIATION...CDC
AREA FORECAST DISCUSSION
NWS BINGHAMTON NY
116 AM EST MON DEC 9 2013
.SYNOPSIS...
A SYSTEM WILL BRING A ROUND OF LIGHT FREEZING DRIZZLE TONIGHT
THROUGH MORNING. MONDAY NIGHT THROUGH THURSDAY...ARCTIC AIR WILL
WORK INTO THE AREA. THIS WILL INCLUDE DEVELOPING ACCUMULATING
LAKE EFFECT SNOW SHOWERS EAST OF THE GREAT LAKES.
&&
.NEAR TERM /THROUGH TODAY/...
1150 PM UPDATE...A QUICK UPDATE TO WX GRIDS AS FREEZING
PRECIP/SLEET ALREADY OCCURRING ACROSS NE PA AND PARTS OF THE
SOUTHERN TIER. THIS TRANSITION TO LIGHT FREEZING RAIN AND SLEET
WILL RAPIDLY SPREAD NORTH ACROSS THE NRN CWA DURING THE NEXT
SEVERAL HOURS AS MODEL SOUNDINGS CONTINUE TO INDICATE MOISTURE TOO
SHALLOW FOR A DENDRITE ZONE. ALSO, DUE TO A LACK OF SIGNIFICANT
LIFT DYNAMIC COOLING IS ALSO ABSENT. MOST AREAS WILL SEE LITTLE OR
NO SNOWFALL PERHAPS AN INCH OVER NRN/ERN PTN OF FA. ALL AREAS WILL
HAVE ICE ACCUMS UP TO ONE TENTH OF AN INCH WHICH WILL MAKE THE
MORNING COMMUTE DIFFICULT.
1005 PM UPDATE...
HV DELAYED PCPN FURTHER BY SVRL HRS AS NEPA IS SEEING VRY LITTLE
PCPN ATTM, THO SRN TIER IS SEEING FLURRIES. KBUF 00Z RAOB STILL
SHOWING DRY AIR IN THE LOWEST 200MB AND THIS IS BEING CONFIRMED BY
OBS ACRS THE REGION. EMPHASIS NOW TURNS TO FRZG PCPN DRG THE
OVRNGT HRS AS SNOW/SLEET DOES NOT APPEAR TO BE THE BIG CONCERN.
ATMOS LOSES MOISTURE IN THE DENDRITE ZONE TONIGHT AS MOISTURE IN
THE AREA IS GETTING THE SQUEEZE PLAY BTWN THE COASTAL LOW AND
GREAT LKS LOW. THUS, HV UPDATED TO GO FRZG DRIZZLE AREAWIDE FOR
TONIGHT WITH A GLAZE OF ICE EXPECTED BY MRNG. THUS WL KEEP THE
ADVISORY GOING AS TEMPS RMN BLO FRZG AND ONLY VRY LGT QPF
EXPECTED.
PREV DISCUSSIONS BLO...
630 PM UPDATE...
PRECIP IS TAKING QUITE AWHILE TO MV INTO FA AS IT SLOWLY WORKS ITS
WAY THRU PA. ACRS NEPA, OBS ARE STILL REPORTING CIGS RANGING FM
6-10KFT AND HIGHER ACRS CNTRL NY. 18Z RAOB OUT OF KBUF SHOWING THE
LOWEST 300MB STILL DRY, HELPING TO EVAPORATE QPF AS IT HEADS NWRD.
APPEARS AS THO 18Z GFS BUFKIT SNDGS HV A BETTER HANDLE ON LOW-LVL
DRY AIR WITH BLYR AT KAVP RMNG TOO DRY FOR SNOW THRU 00Z, WHEREAS
NAM, RAP AND ARW SNDGS INDICATING SNOW SHUD HV BEEN FALLING FOR
THE LAST SVRL HRS DOWN ACRS NEPA.
THUS HV BACKED OFF ON POPS FOR EARLY THIS EVNG WITH CHC LIGHT SNOW
IN NEPA NOT MVG IN FOR ANOTHER FEW HRS, SOMEWHERE BTWN 01Z AND
02Z. THIS AREA OF LIGHT SNOW WL GRADUALLY SPREAD NORTH MVG INTO
SRN TIER BY 03Z AND OVRSPRD RMNDR OF THE AREA BY 06Z. QPF AMNTS
EXPECTED TO BE VRY LGT WITH QPF TOTALS THRU MRNG < 0.10 INCHES.
EXPECT SNOW TO CONT ACRS ENTIRE CWA THRU 06Z (A TAD LATER THAN
PREVIOUSLY THOUGHT) BFR GRADUALLY MIXING WITH SLEET AND EVENTUALLY
-FZRA/-FZDZ TWD DAYBREAK. EXPECT SNOW TO HANG ON LONGEST OVR NRN
ONEIDA CNTY WHERE COLD AIR WL BE DEEPEST. HAVING SAID ALL THIS
EXPECT JUST 1-2 INCHES OF SNOW AND SLEET ACCUMS, HIGHEST OVR EXTRM
ERN SXNS FM MOHAWK VLY DOWN THRU WRN CATS. APPEARS LKLY THAT ALL
AREAS WL SEE A GLAZE OF ICE BY MRNG, MAKING FOR HAZARDOUS TRAVEL
DRG THE MRNG COMMUTE.
315 PM UPDATE...
DOUBLE LOW SYSTEM...YET WE ARE IN BETWEEN...WITH ONE CENTER BY THE
NORTHERN GREAT LAKES AND THE OTHER OFFSHORE OF NEW JERSEY. FORCING
WITH THE SOUTHERN LOW HAS YIELDED A BAND OF HEAVY SNOW IN
SOUTHEAST PA THROUGH NJ...AS ANYONE WATCHING THE PHILADELPHIA
PRO FOOTBALL GAME CAN ATTEST. WE WILL STILL GET A PIECE OF THE
SYSTEM...WITH TOP DOWN MOISTENING YIELDING A BATCH OF SNOW THIS
EVENING SPREADING FROM SOUTHWEST TO NORTHEAST. HOWEVER...SHORTLY
AFTER SNOW ARRIVES...SATURATED LAYER BECOMES SHALLOW TO POINT THAT
TEMPERATURES WITHIN IT BECOME UNSUPPORTIVE OF ICE CRYSTAL
FORMATION...SO QUICK SOUTH-TO-NORTH TRANSITION TO WINTRY MIX OF
LIGHT SLEET AND FREEZING RAIN/DRIZZLE IS FORESEEN OVERNIGHT INTO
EARLY MONDAY...AND EVENTUALLY PLAIN RAIN/DRIZZLE DURING THE DAY
MONDAY.
WINTER WEATHER ADVISORY FOR ENTIRE AREA STILL LOOKS GOOD YET AS
PREVIOUSLY ADVERTISED THIS WILL DEFINITELY BE A LIGHT
PRECIPITATION EVENT. IT HAPPENS TO INCLUDE LIGHT FREEZING
RAIN/FREEZING DRIZZLE AND THUS THE POTENTIAL FOR HAZARDOUS TRAVEL
CONDITIONS ON UNTREATED ROADS...NECESSITATING THE ADVISORY. ONLY
FIGURING ON AN INCH OR LESS OF SNOW- SLEET ACCUMULATION /PERHAPS
CLOSER TO 2 INCHES IN CATSKILLS TO ONEIDA COUNTY/...AND UP TO A
TENTH OF AN INCH OF ICE ACCUMULATION...MOST PLACES LESS.
NON-DIURNAL TEMPERATURES TONIGHT...SLOWLY CLIMBING FROM UPPER 20S
THROUGH LOW 30S INTO MONDAY MORNING...EVENTUALLY REACHING HIGHS OF
MID 30S TO LOW 40S DURING THE DAY.
&&
.SHORT TERM /TONIGHT THROUGH WEDNESDAY/...
130 PM UPDATE...
COLD AIR ADVECTION WILL DOMINATE THE SHORT TERM PERIOD...AS WELL
AS DEVELOPMENT OF WESTERLY-FLOW LAKE EFFECT SNOW FOR SOME.
DEPARTURE OF SYSTEM WELL TO OUR NORTHEAST...AS WELL AS SHALLOW
MOISTURE PROFILE AND WEST-SOUTHWEST FLOW...WILL KEEP THINGS FAIRLY
QUIET MONDAY NIGHT. INTO TUESDAY THOUGH...850MB TEMPERATURES WILL
DIP INTO THE LOWER TO MID TEENS BELOW ZERO CELSIUS WHILE INVERSION
WILL RISE TO DENDRITIC GROWTH LAYER...BEGINNING TO INITIATE BETTER
LAKE RESPONSES. NOT EXPECTING HEAVY ACCUMULATIONS TUESDAY ITSELF
WITH WSW FLOW KEEPING LAKE ONTARIO BAND MAINLY NORTH...YET PERHAPS
STILL SKIMMING NORTHERN ONEIDA COUNTY. HOWEVER...LAKE ERIE BAND
MAY ACTUALLY STRETCH WELL EAST INTO AT LEAST SOUTHERN TIER-FINGER
LAKES FOR AT LEAST SCATTERED SNOW SHOWERS AND PERHAPS BRIEF
HEAVIER BURSTS.
LAKE EFFECT CONTINUES TO BE FAVORABLE TUESDAY NIGHT INTO
WEDNESDAY...AS 1000-500MB THICKNESSES DROP FURTHER INTO THE MID
510S TO LOWER 520S DECAMETER RANGE. HIGHS WEDNESDAY ONLY 20S
AREAWIDE.
MODEL SOUNDINGS SUGGEST DENDRITIC GROWTH TEMPERATURES
DOMINATING THE 3-7 KFT AGL LAYER. PASSING SHORTWAVES THOUGH WILL
FLUCTUATE LOW LEVEL WINDS...WHICH WILL PUSH THE BANDS AROUND AND
ALSO COULD MIS ALIGN WINDS IN THE LOWEST LEVELS. WE WILL HAVE TO
WATCH NORTHERN ONEIDA COUNTY CLOSELY IN MODEL TRENDS FOR POTENTIAL
OF GETTING INVOLVED IN LAKE PROLIFIC ONTARIO SNOW BAND...WHICH
MUCH IF NOT MOST OF THE TIME WILL REMAIN JUST TO THE NORTH.
&&
.LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY/...
215 PM EST UPDATE...
A VERY ACTIVE WEATHER PATTERN IS EXPECTED IN THE EXTENDED
FORECAST. MINOR ADJUSTMENTS WERE MADE TO THE PREVIOUS FORECAST AND
LEANED TOWARDS WPC GUIDANCE. VERY BROAD UPPER LEVEL LOW WILL
SLOWLY DRIFT NORTH AND EAST OF THE REGION RESULTING IN A MUCH
COOLER AIR MASS OVER THE REGION... THUS LE SNOW SHOWERS WILL BE
POSSIBLE THROUGH FRIDAY FOR CENTRAL NY. HIGH PRESSURE WILL BUILD
ACROSS NEW ENGLAND THIS WEEKEND WHICH WILL HELP TEMPS CREEP CLOSER
TOWARDS 32. WITH LARGE DIFFERENCE WITHIN GFS/ECMWF INTO THE
WEEKEND KEPT PREVIOUS FORECAST WITH A SLIGHT CHANCE FOR SNOW
SHOWERS.
&&
.AVIATION /06Z MONDAY THROUGH FRIDAY/...
1230 PM UPDATE...
LIGHT PRECIP WILL CONTINUE THIS MORNING. CIGS WILL FALL FROM
MOSTLY MVFR TO IFR AT ALL BUT SYR AND ELM BY 15Z. SOME IFR CIGS
ALREADY AT BGM AND AVP WHICH SHOULD CONTINUE FOR THE MOST PART.
MUCH OF THE SNOW WILL BE LIGHT ENOUGH THAT VSBYS WILL STAY MVFR.
THE SNOW WILL CHANGE TO SLEET THEN TO FREEZING DRIZZLE. AMOUNTS
WILL BE LIGHT WITH QPF PROBABLY UNDER A TENTH OF AN INCH.
TEMPERATURES SLOWLY RISE THIS MORNING SO THAT PLAIN RAIN AND
DRIZZLE BETWEEN 12 AND 16Z. FIRST WILL BE AVP AND LAST RME TO
CHANGE. VSBYS SHOULD IMPROVE TO VFR AS PRECIP ENDS AROUND 16Z BUT
CIGS WILL REMAIN IFR/MVFR UNTIL 19 TO 00Z THEN IMPROVE TO
VFR/MVFR. STAYING THAT WAY THIS EVENING.
SE WINDS AT 5 TO 10 KTS WILL SHIFT TO SSW MIDDAY THEN TO W LATE
AFTN.
OUTLOOK...
MON OVERNIGHT... MVFR/VFR.
TUE/WED/THU...SCT MVFR SYR/RME IN LAKE EFFECT SNOW SHOWERS. VFR
ELSEWHERE.
&&
.BGM WATCHES/WARNINGS/ADVISORIES...
PA...WINTER WEATHER ADVISORY UNTIL 10 AM EST THIS MORNING FOR
PAZ038>040-043-044-047-048-072.
NY...WINTER WEATHER ADVISORY UNTIL 10 AM EST THIS MORNING FOR
NYZ015>018-022>025-044-045-055-056-062.
WINTER WEATHER ADVISORY UNTIL 1 PM EST THIS AFTERNOON FOR
NYZ009-036-037-046-057.
&&
$$
SYNOPSIS...MDP/PVN
NEAR TERM...MDP/PVN/RRM
SHORT TERM...MDP
LONG TERM...KAH
AVIATION...DJN/TAC
AREA FORECAST DISCUSSION
NWS RALEIGH NC
1250 PM EST MON DEC 9 2013
.SYNOPSIS... A SLOW-MOVING FRONTAL SYSTEM WEST OF THE APPALACHIANS
THIS MORNING WILL DRIFT ACROSS OUR REGION TONIGHT AND TUESDAY.
CHILLY HIGH PRESSURE WILL BUILD INTO OUR REGION TUESDAY NIGHT AND
WEDNESDAY.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 1000 AM MONDAY...
NOT A LOT OF CHANGE NEEDED TO THE FORECAST THIS MORNING. THE CAD
AIRMASS IS FAIRLY WELL ENTRENCHED AND WILL STRUGGLE TO ERODE TODAY.
WHILE THE DEPTH OF THE RESIDUAL COLD POOL HAS DECREASED ON THE 12Z
KGSO RAOB...THERE IS STILL A UNIFORM 40KT FLOW AT 850MB AND ENOUGH
WARM ADVECTION TO KEEP STATIC STABILITY STRONG AND THE CAD LOCKED
IN. RAP AND HRR SOUNDINGS KEEP THE ENTIRE CWA MURKY WELL ON INTO
TONIGHT. THE CURRENT TEMP FORECAST IS AT THE LOWEST END OF THE
GUIDANCE SPECTRUM...SHOWING TEMPS RANGING FROM LOWER 40S TO UPPER
50S. THE BIGGEST POTENTIAL FOR ERROR WILL BE BETWEEN THE TRIANGLE
AND THE COASTAL PLAIN AS THE CAD BOUNDARY TRIES TO RETREAT NORTH AND
WESTWARD. REGARDING POPS...THE AXIS OF DEEPEST MOISTURE IS
CURRENTLY OVER WESTERN NC...AHEAD OF THE SLOW MOVING COLD FRONT WEST
OF THE MOUNTAINS. THE NARROW RAIN BAND THAT CURRENTLY EXTENDS FROM
WEST OF KCLT TO KGSO AND AND INTO VA APPEARS TO BE LINKED TO
ISENTROPIC LIFT BETWEEN 295K AND 305K...WHICH WEAKENS THIS AFTERNOON
AS ANOTHER WAVE OF LOW PRESSURE BEGINS TO FORM TO OUR SOUTHWEST
ALONG THE FRONT. EVEN IF A LULL DEVELOPS...DRIZZLE WILL
CONTINUE...SO HIGH POPS WILL BE MAINTAINED....PARTICULARLY WEST OF
HWY 1. -SMITH
TONIGHT: S/W ENERGY OVER THE CENTRAL ROCKIES WILL PUSH EASTWARD
TODAY INTO TONIGHT... HELPING TO PUSH A COLD FRONT EASTWARD TOWARDS
OUR REGION... WITH A SURFACE LOW DEVELOPING ALONG THE WEDGE FRONT
(AHEAD OF THE APPROACHING COLD FRONT) SOMEWHERE ACROSS OUR
SOUTHEAST/JUST TO THE SOUTH OF OUR REGION LATE TONIGHT. THIS SURFACE
LOW AND CONTINUED MID LEVEL S/W ENERGY EMBEDDED IN THE SOUTHWESTERLY
MID LEVEL FLOW WILL HELP SUPPORT A GOOD CHANCE OF RAIN AREAWIDE.
TEMPS MAY ACTUALLY RISE OR HOLD STEADY OVERNIGHT WHERE THE CAD HOLDS
TODAY. WILL GO WITH LOWS RANGING FROM THE LOW TO MID 40S NW TO LOW
TO MID 50S SE. -BSD
&&
.SHORT TERM /TUESDAY THROUGH TUESDAY NIGHT/...
AS OF 3 AM MONDAY...
TUESDAY...THE SURFACE LOW THAT DEVELOPS ALONG A FRONT SITUATED SW-NE
ACROSS CENTRAL NC WILL AID TO ENHANCE LOW LEVEL CONVERGENCE OVER OUR
REGION. ALOFT...A STRONG JET STREAKING ACROSS THE EASTERN LAKES INTO
SOUTHERN NEW ENGLAND WILL INCREASE UPPER LEVEL DIVERGENCE OVER THE
VIRGINIAS AND NC WHILE THE MID LEVEL S/W RESPONSIBLE FOR GENERATING
THE SURFACE WAVE OVERHEAD WILL QUICKLY SHEAR NEWD ACROSS THE TN AND
MID OH VALLEY. THE COMBINATION OF THE AVAILABLE LIFT AND MOISTURE
SUGGEST RAIN SHOULD BE WIDESPREAD ACROSS THE REGION TO START THE DAY
TUESDAY. MODEL GUIDANCE HAS VARIED AS TO WHERE THE AXIS OF
"HEAVIEST" PRECIP (A QUARTER TO A HALF INCH) WILL SET-UP.
HOWEVER...00Z GFS AND ECMWF HAVE COME INTO BETTER
AGREEMENT...FAVORING THE EASTERN PIEDMONT AND COASTAL PLAIN.
STILL...BETTER DYNAMICS ALOFT WILL RESIDE OVER THE NW PIEDMONT. AT
THIS TIME PLAN TO BROADBRUSH THE PRECIP AMOUNTS ACROSS THE REGION
WITH TWO TO THREE TENTHS EXPECTED IN THE 12Z-18Z TUESDAY TIME FRAME.
MID LEVEL S/W WILL QUICKLY SHEAR OUT TO THE NE TUESDAY
AFTERNOON...PROPELLING THE SURFACE FRONT EASTWARD TO THE COAST BY
TUESDAY AFTERNOON. THUS...SHOULD SEE PRECIP TAPER OFF WEST-TO-EAST
TUESDAY AFTERNOON ACROSS CENTRAL NC. DEVELOPING NW FLOW IN THE LOWER
LEVELS WILL LEAD TO DECREASING CLOUDINESS LATE IN THE DAY.
DEVELOPING DOWNSLOPE FLOW WILL INITIALLY OFFSET COLD AIR ADVECTION.
RESIDUAL CAD AIR MASS ACROSS THE NORTH-NW PIEDMONT SHOULD HOLD TEMPS
IN THE 40S. EXPECT WARMER TEMPS OVER THE SOUTHERN COUNTIES WHERE
TEMPS IN THE 50S (AROUND 60 FAR SE) PROBABLE.
COLDER DRIER AIR WILL OVERSPREAD CENTRAL NC TUESDAY NIGHT AS A
MODIFIED CANADIAN HIGH PRESSURE SYSTEM BUILDS INTO THE REGION.
PARENT HIGH EXPECTED TO BE CENTERED OVER THE CENTRAL APPALACHIANS BY
EARLY WEDNESDAY WITH A SURFACE RIDGE EXTENDING INTO NC. THUS...WHILE
EARLY TUESDAY EVENING WILL BE A BIT BREEZY...LOOKS PLAUSIBLE FOR SFC
WINDS TO DECOUPLE AFTER MIDNIGHT. THIS WILL ALLOW TEMPS TO FALL INTO
THE 20S BY DAYBREAK WEDNESDAY ACROSS THE NORTH...AND NEAR 30 ACROSS
THE SOUTH.
&&
.LONG TERM /WEDNESDAY THROUGH SUNDAY/...
AS OF 330 AM MONDAY...
WEDNESDAY THROUGH FRIDAY...RELATIVELY TRANQUIL WEATHER PERIOD
ANTICIPATED FROM MID WEEK TO THE END OF THE WEEK AS BROAD UPPER
TROUGH COVERS THE EASTERN TWO-THIRDS OF THE NATION. THE NORTHERN
BRANCH WILL BE DOMINATE IN THE BEGINNING...KEEPING THE STORM TRACK
MAINLY ACROSS THE NORTHERN PLAINS-GREAT LAKES AND NEW ENGLAND. THE
SURFACE HIGH THAT COVERS OUR REGION WEDNESDAY WILL QUICKLY SCOOT EWD
BY LATE WEDNESDAY BUT IS REPLACED BY ANOTHER CHILLY HIGH THAT BUILDS
INTO THE MID ATLANTIC IN THE WAKE OF A MID LEVEL S/W CROSSES THE
GREAT LAKES INTO NEW ENGLAND. THUS OUR CURRENT STRETCH OF BE LOW
NORMAL TEMPS WILL CONTINUE. HIGH TEMPS WED AND THU WILL BE IN THE
40S WHILE MIN TEMPS WILL BE IN THE 20S TO AROUND 30.
SATURDAY INTO SUNDAY...OPERATIONAL GFS AND ECMWF OFFER A SIMILAR
SOLUTION FOR THE UPCOMING WEEKEND WEATHER PATTERN...IN SHARP
CONTRAST TOT E 12Z MODEL RUNS WHICH DEPICTED A SOLUTION VERY SIMILAR
TO OUR CURRENT WEATHER PATTERN. MODEL GUIDANCE NOW ADVERTISING A
RETURN FLOW REGIME BECOMING ESTABLISHED FRIDAY NIGHT INTO
SATURDAY...AHEAD OF A FRONTAL SYSTEM DOMINATED BY A S/W IN THE
NORTHERN STREAM. THIS FRONTAL SYSTEM CROSSES OUR REGION SATURDAY
NIGHT WITH CHILLY HIGH PRESSURE BUILDING INTO OUR REGION SUNDAY. FOR
NOW WILL CONFINE THE BEST CHANCE FOR PRECIP TO SATURDAY AND KEEP IT
ALL LIQUID. IF PRECIP COMES INTO THE REGION EARLY ENOUGH FRIDAY
NIGHT...MAY START OUT AS A WINTRY MIX BEFORE QUICKLY TRANSITIONING
TO ALL RAIN. TEMPS EXPECTED TO REMAIN BELOW NORMAL AND HIGHLY
DEPENDENT UPON PRECIP COVERAGE. HIGHS IN THE 40S TO AROUND 50. LOWS
TEMPS IN THE 30S FRIDAY NIGHT AND 30S TO AROUND 40 SATURDAY NIGHT.
&&
.AVIATION /18Z MONDAY THROUGH FRIDAY/...
AS OF 1250 PM MONDAY...
WITH A PERSISTENT MOIST SOUTHWESTERLY FLOW IN PLACE...LOW CLOUDS
CONTINUE TO CAUSE LIFR CONDITIONS THIS AFTERNOON WITH POCKETS OF
RAIN...DRIZZLE AND LOW VSBYS. THERE IS HIGH CONFIDENCE THAT AT
LEAST IFR CONDITIONS WILL CONTINUE...AND IT IS VERY POSSIBLE THAT
LIFR CONDITIONS MAY PERSIST THROUGH THE NIGHT. A COLD FRONT WILL
SLIP INTO NC FROM THE NORTH-NORTHWESTER LATE TONIGHT...WITH WINDS
TURNING TO NORTHERLY BEHIND THE FRONT. MEANWHILE...A 40-50KT LOW
LEVEL JET WILL SURGE BACK ACROSS THE AREA..CAUSING PRECIP TO
CONTINUE BEHIND THE FRONT. IMPROVEMENT IN CEILINGS AND VSBYS WONT
BEGIN UNTIL AFTER AROUND 18Z TUESDAY OR THEREAFTER. LOW LEVEL WIND
SHEAR SHOULD DIMINISH THIS EVENING AS WINDS ABOVE THE SURFACE
RELAX...BUT WILL REDEVELOP TONIGHT WITH THE ARRIVAL OF THE LOW-LEVEL
JET ATOP WEAK SURFACE WINDS.
LOOKING AHEAD: VFR CONDITIONS WILL RETURN TUE NIGHT AS DRY HIGH
PRESSURE BUILDS INTO THE REGION FROM THE WEST. VFR/DRY CONDITIONS
ARE EXPECTED TO PREVAIL THROUGH THE REMAINDER OF THE WORK WEEK.
&&
.RAH WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...WSS
NEAR TERM...BSD/SMITH
SHORT TERM...WSS
LONG TERM...WSS
AVIATION...SMITH
AREA FORECAST DISCUSSION
NWS RALEIGH NC
1000 AM EST MON DEC 9 2013
.SYNOPSIS... A SLOW-MOVING FRONTAL SYSTEM WEST OF THE APPALACHIANS
THIS MORNING WILL DRIFT ACROSS OUR REGION TONIGHT AND TUESDAY.
CHILLY HIGH PRESSURE WILL BUILD INTO OUR REGION TUESDAY NIGHT AND
WEDNESDAY.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 1000 AM MONDAY...
NOT A LOT OF CHANGE NEEDED TO THE FORECAST THIS MORNING. THE CAD
AIRMASS IS FAIRLY WELL ENTRENCHED AND WILL STRUGGLE TO ERODE TODAY.
WHILE THE DEPTH OF THE RESIDUAL COLD POOL HAS DECREASED ON THE 12Z
KGSO RAOB...THERE IS STILL A UNIFORM 40KT FLOW AT 850MB AND ENOUGH
WARM ADVECTION TO KEEP STATIC STABILITY STRONG AND THE CAD LOCKED
IN. RAP AND HRR SOUNDINGS KEEP THE ENTIRE CWA MURKY WELL ON INTO
TONIGHT. THE CURRENT TEMP FORECAST IS AT THE LOWEST END OF THE
GUIDANCE SPECTRUM...SHOWING TEMPS RANGING FROM LOWER 40S TO UPPER
50S. THE BIGGEST POTENTIAL FOR ERROR WILL BE BETWEEN THE TRIANGLE
AND THE COASTAL PLAIN AS THE CAD BOUNDARY TRIES TO RETREAT NORTH AND
WESTWARD. REGARDING POPS...THE AXIS OF DEEPEST MOISTURE IS
CURRENTLY OVER WESTERN NC...AHEAD OF THE SLOW MOVING COLD FRONT WEST
OF THE MOUNTAINS. THE NARROW RAIN BAND THAT CURRENTLY EXTENDS FROM
WEST OF KCLT TO KGSO AND AND INTO VA APPEARS TO BE LINKED TO
ISENTROPIC LIFT BETWEEN 295K AND 305K...WHICH WEAKENS THIS AFTERNOON
AS ANOTHER WAVE OF LOW PRESSURE BEGINS TO FORM TO OUR SOUTHWEST
ALONG THE FRONT. EVEN IF A LULL DEVELOPS...DRIZZLE WILL
CONTINUE...SO HIGH POPS WILL BE MAINTAINED....PARTICULARLY WEST OF
HWY 1. -SMITH
TONIGHT: S/W ENERGY OVER THE CENTRAL ROCKIES WILL PUSH EASTWARD
TODAY INTO TONIGHT... HELPING TO PUSH A COLD FRONT EASTWARD TOWARDS
OUR REGION... WITH A SURFACE LOW DEVELOPING ALONG THE WEDGE FRONT
(AHEAD OF THE APPROACHING COLD FRONT) SOMEWHERE ACROSS OUR
SOUTHEAST/JUST TO THE SOUTH OF OUR REGION LATE TONIGHT. THIS SURFACE
LOW AND CONTINUED MID LEVEL S/W ENERGY EMBEDDED IN THE SOUTHWESTERLY
MID LEVEL FLOW WILL HELP SUPPORT A GOOD CHANCE OF RAIN AREAWIDE.
TEMPS MAY ACTUALLY RISE OR HOLD STEADY OVERNIGHT WHERE THE CAD HOLDS
TODAY. WILL GO WITH LOWS RANGING FROM THE LOW TO MID 40S NW TO LOW
TO MID 50S SE. -BSD
&&
.SHORT TERM /TUESDAY THROUGH TUESDAY NIGHT/...
AS OF 3 AM MONDAY...
TUESDAY...THE SURFACE LOW THAT DEVELOPS ALONG A FRONT SITUATED SW-NE
ACROSS CENTRAL NC WILL AID TO ENHANCE LOW LEVEL CONVERGENCE OVER OUR
REGION. ALOFT...A STRONG JET STREAKING ACROSS THE EASTERN LAKES INTO
SOUTHERN NEW ENGLAND WILL INCREASE UPPER LEVEL DIVERGENCE OVER THE
VIRGINIAS AND NC WHILE THE MID LEVEL S/W RESPONSIBLE FOR GENERATING
THE SURFACE WAVE OVERHEAD WILL QUICKLY SHEAR NEWD ACROSS THE TN AND
MID OH VALLEY. THE COMBINATION OF THE AVAILABLE LIFT AND MOISTURE
SUGGEST RAIN SHOULD BE WIDESPREAD ACROSS THE REGION TO START THE DAY
TUESDAY. MODEL GUIDANCE HAS VARIED AS TO WHERE THE AXIS OF
"HEAVIEST" PRECIP (A QUARTER TO A HALF INCH) WILL SET-UP.
HOWEVER...00Z GFS AND ECMWF HAVE COME INTO BETTER
AGREEMENT...FAVORING THE EASTERN PIEDMONT AND COASTAL PLAIN.
STILL...BETTER DYNAMICS ALOFT WILL RESIDE OVER THE NW PIEDMONT. AT
THIS TIME PLAN TO BROADBRUSH THE PRECIP AMOUNTS ACROSS THE REGION
WITH TWO TO THREE TENTHS EXPECTED IN THE 12Z-18Z TUESDAY TIME FRAME.
MID LEVEL S/W WILL QUICKLY SHEAR OUT TO THE NE TUESDAY
AFTERNOON...PROPELLING THE SURFACE FRONT EASTWARD TO THE COAST BY
TUESDAY AFTERNOON. THUS...SHOULD SEE PRECIP TAPER OFF WEST-TO-EAST
TUESDAY AFTERNOON ACROSS CENTRAL NC. DEVELOPING NW FLOW IN THE LOWER
LEVELS WILL LEAD TO DECREASING CLOUDINESS LATE IN THE DAY.
DEVELOPING DOWNSLOPE FLOW WILL INITIALLY OFFSET COLD AIR ADVECTION.
RESIDUAL CAD AIR MASS ACROSS THE NORTH-NW PIEDMONT SHOULD HOLD TEMPS
IN THE 40S. EXPECT WARMER TEMPS OVER THE SOUTHERN COUNTIES WHERE
TEMPS IN THE 50S (AROUND 60 FAR SE) PROBABLE.
COLDER DRIER AIR WILL OVERSPREAD CENTRAL NC TUESDAY NIGHT AS A
MODIFIED CANADIAN HIGH PRESSURE SYSTEM BUILDS INTO THE REGION.
PARENT HIGH EXPECTED TO BE CENTERED OVER THE CENTRAL APPALACHIANS BY
EARLY WEDNESDAY WITH A SURFACE RIDGE EXTENDING INTO NC. THUS...WHILE
EARLY TUESDAY EVENING WILL BE A BIT BREEZY...LOOKS PLAUSIBLE FOR SFC
WINDS TO DECOUPLE AFTER MIDNIGHT. THIS WILL ALLOW TEMPS TO FALL INTO
THE 20S BY DAYBREAK WEDNESDAY ACROSS THE NORTH...AND NEAR 30 ACROSS
THE SOUTH.
&&
.LONG TERM /WEDNESDAY THROUGH SUNDAY/...
AS OF 330 AM MONDAY...
WEDNESDAY THROUGH FRIDAY...RELATIVELY TRANQUIL WEATHER PERIOD
ANTICIPATED FROM MID WEEK TO THE END OF THE WEEK AS BROAD UPPER
TROUGH COVERS THE EASTERN TWO-THIRDS OF THE NATION. THE NORTHERN
BRANCH WILL BE DOMINATE IN THE BEGINNING...KEEPING THE STORM TRACK
MAINLY ACROSS THE NORTHERN PLAINS-GREAT LAKES AND NEW ENGLAND. THE
SURFACE HIGH THAT COVERS OUR REGION WEDNESDAY WILL QUICKLY SCOOT EWD
BY LATE WEDNESDAY BUT IS REPLACED BY ANOTHER CHILLY HIGH THAT BUILDS
INTO THE MID ATLANTIC IN THE WAKE OF A MID LEVEL S/W CROSSES THE
GREAT LAKES INTO NEW ENGLAND. THUS OUR CURRENT STRETCH OF BE LOW
NORMAL TEMPS WILL CONTINUE. HIGH TEMPS WED AND THU WILL BE IN THE
40S WHILE MIN TEMPS WILL BE IN THE 20S TO AROUND 30.
SATURDAY INTO SUNDAY...OPERATIONAL GFS AND ECMWF OFFER A SIMILAR
SOLUTION FOR THE UPCOMING WEEKEND WEATHER PATTERN...IN SHARP
CONTRAST TOT E 12Z MODEL RUNS WHICH DEPICTED A SOLUTION VERY SIMILAR
TO OUR CURRENT WEATHER PATTERN. MODEL GUIDANCE NOW ADVERTISING A
RETURN FLOW REGIME BECOMING ESTABLISHED FRIDAY NIGHT INTO
SATURDAY...AHEAD OF A FRONTAL SYSTEM DOMINATED BY A S/W IN THE
NORTHERN STREAM. THIS FRONTAL SYSTEM CROSSES OUR REGION SATURDAY
NIGHT WITH CHILLY HIGH PRESSURE BUILDING INTO OUR REGION SUNDAY. FOR
NOW WILL CONFINE THE BEST CHANCE FOR PRECIP TO SATURDAY AND KEEP IT
ALL LIQUID. IF PRECIP COMES INTO THE REGION EARLY ENOUGH FRIDAY
NIGHT...MAY START OUT AS A WINTRY MIX BEFORE QUICKLY TRANSITIONING
TO ALL RAIN. TEMPS EXPECTED TO REMAIN BELOW NORMAL AND HIGHLY
DEPENDENT UPON PRECIP COVERAGE. HIGHS IN THE 40S TO AROUND 50. LOWS
TEMPS IN THE 30S FRIDAY NIGHT AND 30S TO AROUND 40 SATURDAY NIGHT.
&&
.AVIATION /12Z MONDAY THROUGH FRIDAY/...
AS OF 730 AM MONDAY...
24-HR TAF PERIOD: ADVERSE AVIATION CONDITIONS WILL PREVAIL THROUGH
THE TAF PERIOD. EXPECT LIFR CEILINGS THIS MORNING TO CONTINUE
THROUGH AT LEAST MID MORNING... WITH VISBYS POSSIBLY DROPPING TO A
MILE OR LESS OVER THE NEXT COUPLE OF HOURS AS WELL (POSSIBLY LASTING
UNTIL MID MORNING TOO). PERIODS OF RAIN AND DRIZZLE WILL BE POSSIBLE
AT KGSO/KINT/KRDU TODAY... WITH MORE PATCHY RAIN AND DRIZZLE AT KRWI
AND KFAY. EXPECT CIGS WILL BE VERY SLOW TO IMPROVE TODAY... AND MAY
ONLY IMPROVE TO IFR CIGS GIVEN THE CAD AIRMASS OVER CENTRAL NC. IN
ADDITION TO THE POOR CIGS/VISBYS AND RAIN/DRIZZLE... SOUTHWESTERLY
WINDS OF AROUND 40-50 KTS ARE EXPECTED AT AROUND 2 KFT ABOVE THE
SURFACE TODAY... CREATING LOW LEVEL WINDS SHEAR CONDITIONS. THUS...
HAVE ADDED LLWS TO THE TAFS FOR TODAY. EXPECT WINDS AT AROUND 2 KFT
TO WEAKEN BETWEEN 21-00Z TODAY.
LIFR CONDITIONS ARE AGAIN EXPECTED TONIGHT... AS CIGS LOWER AND
VISBYS DROP AFTER 00-03Z. CHANCES FOR RAIN/DRIZZLE WILL CONTINUE AS
WELL.
LOOKING AHEAD: ADVERSE CONDITIONS (IFR/MVFR AND PERHAPS LIFR)
ASSOC/W THE COLD AIR DAMMING WEDGE WILL MOST LIKELY LINGER INTO THE
DAY TUESDAY AS A COLD FRONT APPROACHES FROM THE WEST. VFR CONDITIONS
WILL RETURN TUE NIGHT AS DRY HIGH PRESSURE BUILDS INTO THE REGION
FROM THE WEST. VFR/DRY CONDITIONS ARE EXPECTED TO PREVAIL THROUGH
THE REMAINDER OF THE WORK WEEK.
&&
.RAH WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...WSS
NEAR TERM...BSD/SMITH
SHORT TERM...WSS
LONG TERM...WSS
AVIATION...BSD/VINCENT
AREA FORECAST DISCUSSION
NWS BISMARCK ND
128 PM CST MON DEC 9 2013
.UPDATE...
ISSUED AT 121 PM CST MON DEC 9 2013
BLIZZARD WARNING AND WINTER WEATHER ADVISORIES WILL BE IN EFFECT
AT 3 PM CST THIS AFTERNOON. WAITING FOR THE SUBSIDENCE TO SWEEP
ACROSS THE REGION AND CREATE BLOWING SNOW. SATELLITE PICTURES
DEPICT THIS SUBSIDENCE FROM SASKATCHEWAN INTO NORTHEAST MONTANA.
THE CENTER OF LOW PRESSURE NOW CLOSE TO THE NORTHWEST CORNER OF
ND. THE LOW WILL TRACK SOUTHEAST TO NEAR MAX BY 5 PM BASED ON 18Z
RUC THEN TO NORTHERN STUTSMAN COUNTY BY 7 PM CST. THIS WILL PUT THE
WEST CENTRAL AND SOUTHWEST IN THE STRONG PRESSURE GRADIENT WITH
ADDED PRESSURE RISE TO RAISE WIND GUSTS.
CANCELLED THE WIND CHILL ADVISORY FOR THE AFTERNOON. THOUGH THE
WIND CHILLS WOULD REMAIN COOLER FOR A FEW HOURS BUT THEY ARE NOW
MOVING ABOVE -25 MOST AREAS.
UPDATE ISSUED AT 1047 AM CST MON DEC 9 2013
WILL UPGRADE THE ADVISORY TO A BLIZZARD WARNING FOR THE WEST
CENTRAL...SOUTHWEST AND FAR SOUTH CENTRAL. ALSO ADDING ANOTHER
TIER OF COUNTIES INTO THE WINTER WEATHER ADVISORY...INCLUDING
EMMONS BURLEIGH AND SHERIDAN. EXAMINED MODEL SOUNDINGS AND SEE
STRONG POTENTIAL FOR 45 MPH WIND GUSTS WITH THE ALBERTA CLIPPER
ACROSS THE SOUTHWEST. ALSO...SUPERSATURATED WITH RESPECT TO ICE IN
THE DENDRITIC GROWTH ZONE FROM THE BOUNDARY LAYER TO 700 MB. WITH
THAT IN MINE SEE POTENTIAL TO GENERATE A BURST OF SNOWFALL WITH
THE SYSTEM. NOT MUCH MORE THAN 1 TO 2 INCHES BUT ADDING THE SNOW TO
THE WINDS AND SNOW ON GROUND SHOULD LOWER VISIBILITIES TO LESS THAN
A QUARTER MILE. THE ONLY NEGATIVE I SEE IS THE FACT THAT COLD
DENSE AIR IS IN PLACE..AND THIS COULD LIMIT THE TRANSFER OF
MOMENTUM. OTHERWISE...MOST INGREDIENTS ARE IN PLACE FOR A 3 TO 5
HOUR PERIOD OF BLIZZARD CONDITIONS ACROSS THE WEST CENTRAL AND
SOUTHWEST BEGINNING AROUND 3 AND EXTENDING INTO THE MID EVENING.
BLIZZARD CONDITIONS MAY TAKE A FEW MORE HOURS...AROUND 5 PM OR SO
TO REACH SIOUX COUNTY.
UPDATE ISSUED AT 638 AM CST MON DEC 9 2013
NO CHANGES TO THE EARLY MORNING FORECAST ARE NEEDED AT THIS TIME.
ARCTIC HIGH PRESSURE CENTERED OVER EASTERN MONTANA IS PRODUCING
MOSTLY CLEAR SKIES ACROSS WESTERN AND CENTRAL NORTH DAKOTA EARLY
THIS MORNING. TEMPERATURES AT 6 AM CST WERE GENERALLY 10 TO 20
BELOW WITH WIND CHILLS OF 20 TO 35 BELOW. THE WIND CHILL ADVISORY
CONTINUES THROUGH NOON TODAY. OUR NEXT WEATHER SYSTEM IS CURRENTLY
TAKING SHAPE OVER ALBERTA. THE 10 UTC HRRR IS INDICATING LIGHT
SNOW MOVING INTO WESTERN NORTH DAKOTA BETWEEN 17 AND 18
UTC...WHICH LINES UP WELL WITH THE LATEST FORECAST POPS. STRONGER
WINDS ARE ALSO PROGGED BY THE HRRR TO MOVE INTO KDIK AND KISN
AROUND 21 UTC WHICH IS WHEN THE BLOWING SNOW ADVISORY BEGINS.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 332 AM CST MON DEC 9 2013
THE HIGHLIGHTS OF THE SHORT TERM ARE DANGEROUS MORNING WIND
CHILLS...FOLLOWED BY BLOWING SNOW THIS AFTERNOON AND EVENING.
THE WIND CHILL ADVISORY REMAINS IN EFFECT FOR ALL OF WESTERN AND
CENTRAL NORTH DAKOTA THROUGH 18 UTC AS WIND CHILLS TO -35 F WILL
CONTINUE THIS MORNING. WIND CHILLS CLIMB ABOVE THE -25 F THRESHOLD
FOR ALL LOCATIONS EXCEPT POSSIBLY THE TURTLE MOUNTAINS THIS
AFTERNOON.
OTHERWISE...AN ALBERTA CLIPPER WILL PROPAGATE ACROSS NORTH CENTRAL
INTO SOUTHEAST NORTH DAKOTA LATE THIS AFTERNOON AND INTO THE
EVENING. THE AREA OF GREATEST CONCERN IS WEST OF THE SURFACE LOW
ACROSS WESTERN AND PORTIONS OF NORTH CENTRAL NORTH DAKOTA WHERE A
WINTER WEATHER ADVISORY IS IN EFFECT FOR THIS AFTERNOON AND
EVENING. THE 00 UTC DETERMINISTIC SUITE IS IN GOOD AGREEMENT ON A
BAND OF LIGHT SNOW ALONG AND WEST OF THE SURFACE LOW TRACK...WITH
NEW SNOWFALL AMOUNTS OF GENERALLY ONE INCH OR LESS OF VERY
FLUFFY...DRY SNOW GIVEN THE COLD TEMPERATURES. STRONG NORTHWEST
WINDS ARE ALSO EXPECTED FOR THESE AREAS...GENERALLY AS THE FALLING
SNOW IS ENDING. BASED ON THE 00 UTC NAM/GFS BUFR SOUNDINGS...THE
STRONGEST WINDS ARE EXPECTED ACROSS THE SOUTHWEST WHERE ADIABATIC
LAPSE RATES TO 850-800 MB WITH 45-50 KTS OF WIND AT THE TOP OF THE
MIXED LAYER ARE EXPECTED. THE ONE CAVEAT TO MAXIMIZING WIND GUSTS
WILL BE THE RELATIVE LACK OF STRONG COLD AIR ADVECTION...WITH
PERHAPS VERY WEAK WARM AIR ADVECTION BY EVENING. DID CONSIDER THE
POTENTIAL FOR A GROUND BLIZZARD. HOWEVER...AT THIS TIME COMPACTED
SNOW DEPTHS OF 2 TO 6 INCHES ACROSS MUCH OF WESTERN NORTH DAKOTA
AND THE STRONGEST WINDS NOT OCCURRING AT THE SAME TIME AS THE
HEIGHT OF THE FALLING SNOW SHOULD LIMIT BLIZZARD CRITERIA BEING
MET. THAT SAID...WIDESPREAD BLOWING SNOW AND REDUCED VISIBILITIES
TO ONE HALF MILE ARE EXPECTED...AND CONDITIONS WILL HAVE TO BE
MONITORED CLOSELY SHOULD A BLIZZARD WARNING BE NEEDED. THE AREA
MOST FAVORED FOR THIS POTENTIAL IS THE AMIDON...RHAME AND MARMARTH
AREAS WHERE THE SNOW PACK IS LOCALLY GREATER AND WINDS ARE
EXPECTED TO BE THE STRONGEST.
.LONG TERM...(TUESDAY THROUGH SUNDAY)
ISSUED AT 332 AM CST MON DEC 9 2013
THE MAIN FORECAST CONCERNS IN THE LONG TERM WILL BE POSSIBLE BLOWING
SNOW HIGHLIGHTS ON TUESDAY...THEN TEMPERATURES AND LIGHT SNOW
CHANCES THURSDAY THROUGH SUNDAY NIGHT ALONG AN UNDULATING BAROCLINIC
ZONE OVER THE NORTHERN PLAINS.
CURRENT WINTER WEATHER ADVISORY FOR BLOWING SNOW GOES THROUGH 06 UTC
TUESDAY. IT APPEARS THAT THE STRONGEST BOUNDARY LAYER WINDS WILL BE
MOVING THROUGH CENTRAL NORTH DAKOTA AROUND 06 UTC. WINDS SHOULD
WEAKEN THROUGH 12 UTC TUESDAY AS THE COLD ADVECTION ENDS AND
PRESSURE FALL RISE COUPLET HAS MOVED EAST OF THE AREA. WINDS
INCREASE AGAIN ON TUESDAY AS ANOTHER PIECE OF ARCTIC HIGH PRESSURE
DROPS INTO THE AREA. WINDS WILL NOT BE AS STRONG AS MONDAY AND WE
SHOULD GET A GOOD IDEA ON THE IMPACTS OF THE BLOWING SNOW MONDAY TO
DISCERN WHETHER OR NOT THE ADVISORY WILL NEED TO BE EXTENDED INTO
TUESDAY. THEREFORE WILL NOT ISSUE ANYTHING AT THIS TIME.
COLD AND DRY ON WEDNESDAY AS THE ARCTIC HIGH TRACKS SOUTHEAST ACROSS
THE FORECAST AREA.
THURSDAY THROUGH SUNDAY NIGHT A NORTHWEST FLOW PATTERN TAKES SHAPE.
SHORTWAVES MOVING THROUGH THE MEAN FLOW WILL INDUCE LEE SIDE LOW
PRESSURE SYSTEMS THAT WILL TRACK SOUTHEAST FROM THE NORTHERN HIGH
PLAINS INTO THE CENTRAL AND NORTHERN PLAINS. EACH LOW WILL PRODUCE
AN AREA OF LIGHT WARM ADVECTION SNOWS OVER WESTERN AND CENTRAL NORTH
DAKOTA AS THE RIDE SOUTHEAST ALONG THE BAROCLINIC ZONE. IN
ADDITION...EACH WAVE SHOULD BRING IN A LITTLE WARMER AIR...WITH
HIGHS POSSIBLY CLIMBING ABOVE FREEZING BY SUNDAY OVER THE SOUTHWEST.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z TUESDAY AFTERNOON)
ISSUED AT 121 PM CST MON DEC 9 2013
MAIN HAZARD TO AVIATION WILL BE STRONG WINDS...AND BLIZZARD
CONDITIONS ACROSS THE SOUTHWEST AND WEST CENTRAL...IMPACTING
PRIMARILY KDIK...BUT KISN-KBIS WILL BE IN THE PERIPHERY. MAIN
TIMING WILL BE BETWEEN 3 PM AND MIDNIGHT. OUTSIDE OF THIS
AREA...MVFR TO OCNLY IFR CONDITIONS AFTER 21Z WILL BE FOUND IN
AREAS OF SNOW AND BLOWING SNOW.
&&
.BIS WATCHES/WARNINGS/ADVISORIES...
WINTER WEATHER ADVISORY UNTIL MIDNIGHT CST TONIGHT FOR
NDZ001>004-009>012-019>022-034-035-046.
BLIZZARD WARNING UNTIL MIDNIGHT CST /11 PM MST/ TONIGHT FOR
NDZ017-018-031>033-040>045.
&&
$$
UPDATE...WAA
SHORT TERM...AYD
LONG TERM...TWH
AVIATION...WAA
AREA FORECAST DISCUSSION
NWS BISMARCK ND
1102 AM CST MON DEC 9 2013
.UPDATE...
ISSUED AT 1047 AM CST MON DEC 9 2013
WILL UPGRADE THE ADVISORY TO A BLIZZARD WARNING FOR THE WEST
CENTRAL...SOUTHWEST AND FAR SOUTH CENTRAL. ALSO ADDING ANOTHER
TIER OF COUNTIES INTO THE WINTER WEATHER ADVISORY...INCLUDING
EMMONS BURLEIGH AND SHERIDAN. EXAMINED MODEL SOUNDINGS AND SEE
STRONG POTENTIAL FOR 45 MPH WIND GUSTS WITH THE ALBERTA CLIPPER
ACROSS THE SOUTHWEST. ALSO...SUPERSATURATED WITH RESPECT TO ICE IN
THE DENDRITIC GROWTH ZONE FROM THE BOUNDARY LAYER TO 700 MB. WITH
THAT IN MINE SEE POTENTIAL TO GENERATE A BURST OF SNOWFALL WITH
THE SYSTEM. NOT MUCH MORE THAN 1 TO 2 INCHES BUT ADDING THE SNOW TO
THE WINDS AND SNOW ON GROUND SHOULD LOWER VISIBILITIES TO LESS THAN
A QUARTER MILE. THE ONLY NEGATIVE I SEE IS THE FACT THAT COLD
DENSE AIR IS IN PLACE..AND THIS COULD LIMIT THE TRANSFER OF
MOMENTUM. OTHERWISE...MOST INGREDIENTS ARE IN PLACE FOR A 3 TO 5
HOUR PERIOD OF BLIZZARD CONDITIONS ACROSS THE WEST CENTRAL AND
SOUTHWEST BEGINNING AROUND 3 AND EXTENDING INTO THE MID EVENING.
BLIZZARD CONDITIONS MAY TAKE A FEW MORE HOURS...AROUND 5 PM OR SO
TO REACH SIOUX COUNTY.
UPDATE ISSUED AT 638 AM CST MON DEC 9 2013
NO CHANGES TO THE EARLY MORNING FORECAST ARE NEEDED AT THIS TIME.
ARCTIC HIGH PRESSURE CENTERED OVER EASTERN MONTANA IS PRODUCING
MOSTLY CLEAR SKIES ACROSS WESTERN AND CENTRAL NORTH DAKOTA EARLY
THIS MORNING. TEMPERATURES AT 6 AM CST WERE GENERALLY 10 TO 20
BELOW WITH WIND CHILLS OF 20 TO 35 BELOW. THE WIND CHILL ADVISORY
CONTINUES THROUGH NOON TODAY. OUR NEXT WEATHER SYSTEM IS CURRENTLY
TAKING SHAPE OVER ALBERTA. THE 10 UTC HRRR IS INDICATING LIGHT
SNOW MOVING INTO WESTERN NORTH DAKOTA BETWEEN 17 AND 18
UTC...WHICH LINES UP WELL WITH THE LATEST FORECAST POPS. STRONGER
WINDS ARE ALSO PROGGED BY THE HRRR TO MOVE INTO KDIK AND KISN
AROUND 21 UTC WHICH IS WHEN THE BLOWING SNOW ADVISORY BEGINS.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 332 AM CST MON DEC 9 2013
THE HIGHLIGHTS OF THE SHORT TERM ARE DANGEROUS MORNING WIND
CHILLS...FOLLOWED BY BLOWING SNOW THIS AFTERNOON AND EVENING.
THE WIND CHILL ADVISORY REMAINS IN EFFECT FOR ALL OF WESTERN AND
CENTRAL NORTH DAKOTA THROUGH 18 UTC AS WIND CHILLS TO -35 F WILL
CONTINUE THIS MORNING. WIND CHILLS CLIMB ABOVE THE -25 F THRESHOLD
FOR ALL LOCATIONS EXCEPT POSSIBLY THE TURTLE MOUNTAINS THIS
AFTERNOON.
OTHERWISE...AN ALBERTA CLIPPER WILL PROPAGATE ACROSS NORTH CENTRAL
INTO SOUTHEAST NORTH DAKOTA LATE THIS AFTERNOON AND INTO THE
EVENING. THE AREA OF GREATEST CONCERN IS WEST OF THE SURFACE LOW
ACROSS WESTERN AND PORTIONS OF NORTH CENTRAL NORTH DAKOTA WHERE A
WINTER WEATHER ADVISORY IS IN EFFECT FOR THIS AFTERNOON AND
EVENING. THE 00 UTC DETERMINISTIC SUITE IS IN GOOD AGREEMENT ON A
BAND OF LIGHT SNOW ALONG AND WEST OF THE SURFACE LOW TRACK...WITH
NEW SNOWFALL AMOUNTS OF GENERALLY ONE INCH OR LESS OF VERY
FLUFFY...DRY SNOW GIVEN THE COLD TEMPERATURES. STRONG NORTHWEST
WINDS ARE ALSO EXPECTED FOR THESE AREAS...GENERALLY AS THE FALLING
SNOW IS ENDING. BASED ON THE 00 UTC NAM/GFS BUFR SOUNDINGS...THE
STRONGEST WINDS ARE EXPECTED ACROSS THE SOUTHWEST WHERE ADIABATIC
LAPSE RATES TO 850-800 MB WITH 45-50 KTS OF WIND AT THE TOP OF THE
MIXED LAYER ARE EXPECTED. THE ONE CAVEAT TO MAXIMIZING WIND GUSTS
WILL BE THE RELATIVE LACK OF STRONG COLD AIR ADVECTION...WITH
PERHAPS VERY WEAK WARM AIR ADVECTION BY EVENING. DID CONSIDER THE
POTENTIAL FOR A GROUND BLIZZARD. HOWEVER...AT THIS TIME COMPACTED
SNOW DEPTHS OF 2 TO 6 INCHES ACROSS MUCH OF WESTERN NORTH DAKOTA
AND THE STRONGEST WINDS NOT OCCURRING AT THE SAME TIME AS THE
HEIGHT OF THE FALLING SNOW SHOULD LIMIT BLIZZARD CRITERIA BEING
MET. THAT SAID...WIDESPREAD BLOWING SNOW AND REDUCED VISIBILITIES
TO ONE HALF MILE ARE EXPECTED...AND CONDITIONS WILL HAVE TO BE
MONITORED CLOSELY SHOULD A BLIZZARD WARNING BE NEEDED. THE AREA
MOST FAVORED FOR THIS POTENTIAL IS THE AMIDON...RHAME AND MARMARTH
AREAS WHERE THE SNOW PACK IS LOCALLY GREATER AND WINDS ARE
EXPECTED TO BE THE STRONGEST.
.LONG TERM...(TUESDAY THROUGH SUNDAY)
ISSUED AT 332 AM CST MON DEC 9 2013
THE MAIN FORECAST CONCERNS IN THE LONG TERM WILL BE POSSIBLE BLOWING
SNOW HIGHLIGHTS ON TUESDAY...THEN TEMPERATURES AND LIGHT SNOW
CHANCES THURSDAY THROUGH SUNDAY NIGHT ALONG AN UNDULATING BAROCLINIC
ZONE OVER THE NORTHERN PLAINS.
CURRENT WINTER WEATHER ADVISORY FOR BLOWING SNOW GOES THROUGH 06 UTC
TUESDAY. IT APPEARS THAT THE STRONGEST BOUNDARY LAYER WINDS WILL BE
MOVING THROUGH CENTRAL NORTH DAKOTA AROUND 06 UTC. WINDS SHOULD
WEAKEN THROUGH 12 UTC TUESDAY AS THE COLD ADVECTION ENDS AND
PRESSURE FALL RISE COUPLET HAS MOVED EAST OF THE AREA. WINDS
INCREASE AGAIN ON TUESDAY AS ANOTHER PIECE OF ARCTIC HIGH PRESSURE
DROPS INTO THE AREA. WINDS WILL NOT BE AS STRONG AS MONDAY AND WE
SHOULD GET A GOOD IDEA ON THE IMPACTS OF THE BLOWING SNOW MONDAY TO
DISCERN WHETHER OR NOT THE ADVISORY WILL NEED TO BE EXTENDED INTO
TUESDAY. THEREFORE WILL NOT ISSUE ANYTHING AT THIS TIME.
COLD AND DRY ON WEDNESDAY AS THE ARCTIC HIGH TRACKS SOUTHEAST ACROSS
THE FORECAST AREA.
THURSDAY THROUGH SUNDAY NIGHT A NORTHWEST FLOW PATTERN TAKES SHAPE.
SHORTWAVES MOVING THROUGH THE MEAN FLOW WILL INDUCE LEE SIDE LOW
PRESSURE SYSTEMS THAT WILL TRACK SOUTHEAST FROM THE NORTHERN HIGH
PLAINS INTO THE CENTRAL AND NORTHERN PLAINS. EACH LOW WILL PRODUCE
AN AREA OF LIGHT WARM ADVECTION SNOWS OVER WESTERN AND CENTRAL NORTH
DAKOTA AS THE RIDE SOUTHEAST ALONG THE BAROCLINIC ZONE. IN
ADDITION...EACH WAVE SHOULD BRING IN A LITTLE WARMER AIR...WITH
HIGHS POSSIBLY CLIMBING ABOVE FREEZING BY SUNDAY OVER THE SOUTHWEST.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z TUESDAY AFTERNOON)
ISSUED AT 1047 AM CST MON DEC 9 2013
MAIN HAZARD TO AVIATION WILL BE STRONG WINDS...AND BLIZZARD
CONDITIONS ACROSS THE SOUTHWEST AND WEST CENTRAL...IMPACTING
PRIMARILY KDIK...BUT KISN-KBIS WILL BE ION THE PERIPHERY. MAIN
TIMING WILL BE BETWEEN 3 PM AND MIDNIGHT. OUTSIDE OF THIS
AREA...MVFR TO OCNLY IFR CONDITIONS AFTER 21Z WILL BE FOUND IN
AREAS OF SNOW AND BLOWING SNOW.
&&
.BIS WATCHES/WARNINGS/ADVISORIES...
WINTER WEATHER ADVISORY FROM 3 PM THIS AFTERNOON TO MIDNIGHT CST
TONIGHT FOR NDZ001>004-009>012-019>022-034-035-046.
BLIZZARD WARNING FROM 3 PM CST /2 PM MST/ THIS AFTERNOON TO
MIDNIGHT CST /11 PM MST/ TONIGHT FOR NDZ017-018-031>033-040>045.
WIND CHILL ADVISORY UNTIL 3 PM CST THIS AFTERNOON FOR NDZ003>005-
011>013-022-023-025-036-037-047-048-050-051.
&&
$$
UPDATE...WAA
SHORT TERM...AYD
LONG TERM...TWH
AVIATION...WAA
AREA FORECAST DISCUSSION
NWS BISMARCK ND
638 AM CST MON DEC 9 2013
.UPDATE...
ISSUED AT 638 AM CST MON DEC 9 2013
NO CHANGES TO THE EARLY MORNING FORECAST ARE NEEDED AT THIS TIME.
ARCTIC HIGH PRESSURE CENTERED OVER EASTERN MONTANA IS PRODUCING
MOSTLY CLEAR SKIES ACROSS WESTERN AND CENTRAL NORTH DAKOTA EARLY
THIS MORNING. TEMPERATURES AT 6 AM CST WERE GENERALLY 10 TO 20
BELOW WITH WIND CHILLS OF 20 TO 35 BELOW. THE WIND CHILL ADVISORY
CONTINUES THROUGH NOON TODAY. OUR NEXT WEATHER SYSTEM IS CURRENTLY
TAKING SHAPE OVER ALBERTA. THE 10 UTC HRRR IS INDICATING LIGHT
SNOW MOVING INTO WESTERN NORTH DAKOTA BETWEEN 17 AND 18
UTC...WHICH LINES UP WELL WITH THE LATEST FORECAST POPS. STRONGER
WINDS ARE ALSO PROGGED BY THE HRRR TO MOVE INTO KDIK AND KISN
AROUND 21 UTC WHICH IS WHEN THE BLOWING SNOW ADVISORY BEGINS.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 332 AM CST MON DEC 9 2013
THE HIGHLIGHTS OF THE SHORT TERM ARE DANGEROUS MORNING WIND
CHILLS...FOLLOWED BY BLOWING SNOW THIS AFTERNOON AND EVENING.
THE WIND CHILL ADVISORY REMAINS IN EFFECT FOR ALL OF WESTERN AND
CENTRAL NORTH DAKOTA THROUGH 18 UTC AS WIND CHILLS TO -35 F WILL
CONTINUE THIS MORNING. WIND CHILLS CLIMB ABOVE THE -25 F THRESHOLD
FOR ALL LOCATIONS EXCEPT POSSIBLY THE TURTLE MOUNTAINS THIS
AFTERNOON.
OTHERWISE...AN ALBERTA CLIPPER WILL PROPAGATE ACROSS NORTH CENTRAL
INTO SOUTHEAST NORTH DAKOTA LATE THIS AFTERNOON AND INTO THE
EVENING. THE AREA OF GREATEST CONCERN IS WEST OF THE SURFACE LOW
ACROSS WESTERN AND PORTIONS OF NORTH CENTRAL NORTH DAKOTA WHERE A
WINTER WEATHER ADVISORY IS IN EFFECT FOR THIS AFTERNOON AND
EVENING. THE 00 UTC DETERMINISTIC SUITE IS IN GOOD AGREEMENT ON A
BAND OF LIGHT SNOW ALONG AND WEST OF THE SURFACE LOW TRACK...WITH
NEW SNOWFALL AMOUNTS OF GENERALLY ONE INCH OR LESS OF VERY
FLUFFY...DRY SNOW GIVEN THE COLD TEMPERATURES. STRONG NORTHWEST
WINDS ARE ALSO EXPECTED FOR THESE AREAS...GENERALLY AS THE FALLING
SNOW IS ENDING. BASED ON THE 00 UTC NAM/GFS BUFR SOUNDINGS...THE
STRONGEST WINDS ARE EXPECTED ACROSS THE SOUTHWEST WHERE ADIABATIC
LAPSE RATES TO 850-800 MB WITH 45-50 KTS OF WIND AT THE TOP OF THE
MIXED LAYER ARE EXPECTED. THE ONE CAVEAT TO MAXIMIZING WIND GUSTS
WILL BE THE RELATIVE LACK OF STRONG COLD AIR ADVECTION...WITH
PERHAPS VERY WEAK WARM AIR ADVECTION BY EVENING. DID CONSIDER THE
POTENTIAL FOR A GROUND BLIZZARD. HOWEVER...AT THIS TIME COMPACTED
SNOW DEPTHS OF 2 TO 6 INCHES ACROSS MUCH OF WESTERN NORTH DAKOTA
AND THE STRONGEST WINDS NOT OCCURRING AT THE SAME TIME AS THE
HEIGHT OF THE FALLING SNOW SHOULD LIMIT BLIZZARD CRITERIA BEING
MET. THAT SAID...WIDESPREAD BLOWING SNOW AND REDUCED VISIBILITIES
TO ONE HALF MILE ARE EXPECTED...AND CONDITIONS WILL HAVE TO BE
MONITORED CLOSELY SHOULD A BLIZZARD WARNING BE NEEDED. THE AREA
MOST FAVORED FOR THIS POTENTIAL IS THE AMIDON...RHAME AND MARMARTH
AREAS WHERE THE SNOW PACK IS LOCALLY GREATER AND WINDS ARE
EXPECTED TO BE THE STRONGEST.
.LONG TERM...(TUESDAY THROUGH SUNDAY)
ISSUED AT 332 AM CST MON DEC 9 2013
THE MAIN FORECAST CONCERNS IN THE LONG TERM WILL BE POSSIBLE BLOWING
SNOW HIGHLIGHTS ON TUESDAY...THEN TEMPERATURES AND LIGHT SNOW
CHANCES THURSDAY THROUGH SUNDAY NIGHT ALONG AN UNDULATING BAROCLINIC
ZONE OVER THE NORTHERN PLAINS.
CURRENT WINTER WEATHER ADVISORY FOR BLOWING SNOW GOES THROUGH 06 UTC
TUESDAY. IT APPEARS THAT THE STRONGEST BOUNDARY LAYER WINDS WILL BE
MOVING THROUGH CENTRAL NORTH DAKOTA AROUND 06 UTC. WINDS SHOULD
WEAKEN THROUGH 12 UTC TUESDAY AS THE COLD ADVECTION ENDS AND
PRESSURE FALL RISE COUPLET HAS MOVED EAST OF THE AREA. WINDS
INCREASE AGAIN ON TUESDAY AS ANOTHER PIECE OF ARCTIC HIGH PRESSURE
DROPS INTO THE AREA. WINDS WILL NOT BE AS STRONG AS MONDAY AND WE
SHOULD GET A GOOD IDEA ON THE IMPACTS OF THE BLOWING SNOW MONDAY TO
DISCERN WHETHER OR NOT THE ADVISORY WILL NEED TO BE EXTENDED INTO
TUESDAY. THEREFORE WILL NOT ISSUE ANYTHING AT THIS TIME.
COLD AND DRY ON WEDNESDAY AS THE ARCTIC HIGH TRACKS SOUTHEAST ACROSS
THE FORECAST AREA.
THURSDAY THROUGH SUNDAY NIGHT A NORTHWEST FLOW PATTERN TAKES SHAPE.
SHORTWAVES MOVING THROUGH THE MEAN FLOW WILL INDUCE LEE SIDE LOW
PRESSURE SYSTEMS THAT WILL TRACK SOUTHEAST FROM THE NORTHERN HIGH
PLAINS INTO THE CENTRAL AND NORTHERN PLAINS. EACH LOW WILL PRODUCE
AN AREA OF LIGHT WARM ADVECTION SNOWS OVER WESTERN AND CENTRAL NORTH
DAKOTA AS THE RIDE SOUTHEAST ALONG THE BAROCLINIC ZONE. IN
ADDITION...EACH WAVE SHOULD BRING IN A LITTLE WARMER AIR...WITH
HIGHS POSSIBLY CLIMBING ABOVE FREEZING BY SUNDAY OVER THE SOUTHWEST.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z TUESDAY MORNING)
ISSUED AT 638 AM CST MON DEC 9 2013
ANOTHER MORNING OF SCATTERED STRATUS DECKS WITH FLURRIES THAT ARE
HARD TO SEE ON SATELLITE AND RADAR WILL CONTINUE. ALTHOUGH THE
SATELLITE HAS SHOWN A DECREASING TREND IN STRATUS OVER THE PAST
FEW HOURS AND HAVE STARTED EVERYONE OFF MAINLY CLEAR OR WITH ONLY
A SCATTERED STRATUS DECK AND NO FLURRIES. THEREAFTER...AN ALBERTA
CLIPPER WILL IMPACT WESTERN AND CENTRAL NORTH DAKOTA MONDAY
AFTERNOON AND EVENING. IFR CONDITIONS IN SNOW...BLOWING SNOW AND
STRONG NORTHWEST WINDS ARE EXPECTED.
&&
.BIS WATCHES/WARNINGS/ADVISORIES...
WINTER WEATHER ADVISORY FROM 3 PM CST /2 PM MST/ THIS AFTERNOON
TO MIDNIGHT CST /11 PM MST/ TONIGHT FOR NDZ001>004-009>012-
017>019-021-031>033-040-041-043-044.
WIND CHILL ADVISORY UNTIL NOON CST /11 AM MST/ TODAY FOR
NDZ001>005-009>013-017>023-025-031>037-040>048-050-051.
&&
$$
UPDATE...TWH
SHORT TERM...AYD
LONG TERM...TWH
AVIATION...TWH
AREA FORECAST DISCUSSION
NWS CHARLESTON WV
415 PM EST MON DEC 9 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 TUESDAY/...
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 /TUESDAY NIGHT 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 /21Z MONDAY THROUGH SATURDAY/...
PRIMARILY MVFR STRATUS INTO TONIGHT WITH SOME IFR CIGS/VSBY IN THE
MOUNTAINS AMID PATCHY DZ. SOME BREAKS POSSIBLE ACROSS SE OH AND NE
KY TONIGHT.
AN UPPER LEVEL TROF WILL APPROACH LATE TONIGHT AND COMBINED WITH A
SURFACE WAVE TO THE SE WILL ALLOW SN OVERSPREAD MUCH OF THE
AREA...HEAVIEST ACROSS THE LOWLANDS AND MOUNTAINS. CIGS WILL LOWER
INTO IFR/LIFR ALONG WITH VSBY AS THE SN MOVES IN 09 TO 15Z. SOME
IMPROVEMENT AFTER 15Z AS CIGS/VSBY RISE INTO MVFR AND TRYING TO
SCT OU ACROSS SE OH/NE KY/W WV IN AFTERNOON.
FORECAST CONFIDENCE AND ALTERNATE SCENARIOS THROUGH 18Z TUESDAY...
FORECAST CONFIDENCE: MEDIUM.
ALTERNATE SCENARIOS: TIMING OF IFR/LIFR CIGS MAY VARY FROM CURRENT
FORECAST.
EXPERIMENTAL TABLE OF FLIGHT CATEGORY OBJECTIVELY SHOWS CONSISTENCY
OF WFO FORECAST TO AVAILABLE MODEL INFORMATION:
H = HIGH: TAF CONSISTENT WITH ALL MODELS OR ALL BUT ONE MODEL.
M = MEDIUM: TAF HAS VARYING LEVEL OF CONSISTENCY WITH MODELS.
L = LOW: TAF INCONSISTENT WITH ALL MODELS OR ALL BUT ONE MODEL.
UTC 1HRLY 20 21 22 23 00 01 02 03 04 05 06 07
EST 1HRLY 15 16 17 18 19 20 21 22 23 00 01 02
CRW CONSISTENCY H H H H H H H H H H H H
HTS CONSISTENCY H H H H H H M M M M M H
BKW CONSISTENCY H H H H L L L L L M H H
EKN CONSISTENCY H H H H H L L L L L L L
PKB CONSISTENCY H H H H H H H H H M M H
CKB CONSISTENCY H H H H H H H H H H H H
AFTER 18Z TUESDAY...
IFR POSSIBLE IN SNOW...SLEET...FREEZING RAIN AND RAIN SATURDAY.
&&
.EQUIPMENT...
ADDITIONAL PARTS FOR PARKERSBURG ASOS ARE EXPECTED TO ARRIVE BY TUE
MORNING. AUTOMATED OBSERVATIONS WILL BE UNAVAILABLE UNTIL AT LEAST
TUE.
&&
.RLX WATCHES/WARNINGS/ADVISORIES...
WV...WINTER WEATHER ADVISORY FROM 1 AM TO 3 PM EST TUESDAY FOR
WVZ005>011-013>020-024>040-046-047.
OH...NONE.
KY...WINTER WEATHER ADVISORY FROM 1 AM TO 3 PM EST TUESDAY FOR
KYZ103-105.
VA...WINTER WEATHER ADVISORY FROM 1 AM TO 3 PM EST TUESDAY FOR
VAZ003-004.
&&
$$
SYNOPSIS...TRM/RPY/30
NEAR TERM...30
SHORT TERM...TRM
LONG TERM...RPY
AVIATION...30
EQUIPMENT...TRM
AREA FORECAST DISCUSSION
NWS CHARLESTON WV
305 PM EST MON DEC 9 2013
.SYNOPSIS...
A WEAK SYSTEM CROSSES LATE TONIGHT INTO TUESDAY WITH SOME SNOW
EXPECTED. CHILLY DRY HIGH PRESSURE FOR WEDNESDAY INTO FRIDAY.
ANOTHER SYSTEM THIS WEEKEND.
&&
.NEAR TERM /THROUGH TUESDAY/...
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 /TUESDAY NIGHT THROUGH THURSDAY/...
ACTIVE AT THE OUTSET OF THE PERIOD ON TUESDAY MORNING WITH A
QUICK-HITTING SYSTEM PUSHING ACROSS THE AREA. YET ANOTHER WAVE OF
LOW PRESSURE WILL BE RIDING ALONG THE QUASI-STATIONARY FRONT STILL
TO OUR SOUTHEAST WHICH IS PROGGED TO BE LOCATED NEAR THE TN/NC/GA
AREA AT 12Z TUE. MEANWHILE AN UPPER TROUGH WILL BE PROGRESSING
EASTWARD QUICKLY ACROSS THE LOWER/MID OHIO RIVER VALLEY TUE MORNING.
EXPECT TWO DISTINCT AREAS OF PRECIP AT THE OUTSET...ONE ENTERING THE
SE OHIO ZONES AND THE OTHER PUSHING UP FROM THE SW WITH THE SFC LOW.
THESE SHOULD MERGE OVER THE NORTHEAST ZONES BY MID-LATE MORNING ON
IT/S WAY OUT OF OUR AREA. VARIOUS QPF OUTPUT DEPICTING ROUGHLY
0.1-0.2 INCHES IN GENERAL...WITH SOME HIGHER AMOUNTS PARTICULARLY ON
THE FINER RESOLUTION NAM12. TOUGH CALL ON SNOWFALL AMOUNTS WITH SOME
DIFFERENCES IN TIMING OF THE HIGHEST QPF AND WITH THE SYSTEM BEING
SUCH A FAST-MOVER. A GENERAL INCH OR SO APPEARS REASONABLE FOR MUCH
OF THE LOWLANDS LATE MON NIGHT GOING INTO TUE MORNING. THE AREA
HOWEVER COMES UNDER INFLUENCE OF RIGHT ENTRANCE REGION OF STRONG JET
JUST TO OUR NORTHWEST AROUND THE 12Z TUE TIME FRAME WITH GOOD
UNIDIRECTIONAL SPEED SHEAR. A BIT CONCERNED WITH PROGGED EPV AND
THETA-E LAPSE RATE VALS WITH GOOD SATURATION ABOVE THE COLD
DOME...NOT TO MENTION SOME WEAK ELEVATED CAPE...THAT SOME LOCATIONS
MAY SEE SOME ENHANCEMENT OF SNOWFALL RATES/ACCUMULATIONS IN NARROW
MESOSCALE BANDS THROUGH SLANTWISE AND/OR UPRIGHT CONVECTION.
CONSIDERED AN ADVISORY FOR TUE MORNING...BUT AFTER COLLABORATION
WITH SURROUNDING OFFICES DECIDED TO ALLOW DAY SHIFT ONE MORE LOOK AT
LATEST DATA. DID BUMP UP SNOW AMOUNTS...AGAIN...TO AROUND THE 1-2
INCH RANGE WITH SOME 2-3 ACROSS THE NORTHEAST ZONES. SNOWFALL WILL
PRIMARILY BE CONFINED NEAR THE EASTERN MOUNTAINS BY 18Z TUE WITH
ONLY A SLIGHT CHANCE OF LIGHT SNOW REMAINING BY 00Z WED. ALSO NUDGED
MAX TEMPS DOWN A BIT TUESDAY PER LATEST MOS GUIDANCE AND 925MB TEMPS
SUPPORTING. MANY LOCATIONS TUESDAY WILL STRUGGLE TO REACH THE
FREEZING MARK.
HIGH PRESSURE PUSHES IN FROM THE WEST TUESDAY NIGHT AND WEDNESDAY
WITH RAPIDLY CLEARING SKIES TUESDAY NIGHT WITH HIGH PRESSURE CENTER
LOCATED OVER THE SOUTHERN ZONES BY 12Z WED. CLEARING SKIES AND LIGHT
WINDS WILL ALLOW GOOD COOLING WITH TEENS EXPECTED FOR MOST
LOCATIONS...AND EVEN SOME SINGLE DIGITS POSSIBLE OVER SE OHIO AND OF
COURSE THE EASTERN HIGH COUNTRY. AN UPPER TROUGH WILL PASS BY TO THE
NORTH OF THE FORECAST AREA WEDNESDAY RESULTING IN PERHAPS A FEW MORE
CLOUDS NORTH. BUT OTHERWISE A DRY AND SUNNY...BUT COOL...DAY IS ON
TAP FOR WEDNESDAY. MAX TEMPS GENERALLY IN THE LOW/MID 30S FOR THE
LOWLANDS STILL APPEAR ON TRACK WITH VERY LITTLE CHANGE FROM PREV
FCST. SFC WINDS WILL COME AROUND TO THE SOUTHWEST AS SFC HIGH
CONTINUES TO PUSH OFF TO THE EAST. A QUICK MOVING FRONT WILL PUSH
ACROSS THE AREA WED NIGHT...BUT LITTLE MOISTURE WITH IT RESULTS IN
ONLY A BRIEF INCREASE IN CLOUD COVER AND SOME BREEZY POST-FRONTAL
WINDS WED NIGHT...EXCEPT FOR THE FAR NORTHEAST ZONES WHERE JUST
ENOUGH MOISTURE DEPTH MAY BE ENOUGH TO SQUEEZE OUT A LIGHT SNOW
SHOWER. THUS WILL CARRY SLIGHT CHANCE POPS HERE WED NIGHT. SNOW
ACCUMS WILL NOT BE AN ISSUE HOWEVER...WITH ONLY A DUSTING TO A FEW
TENTHS POSSIBLE. MINS AGAIN WILL BE JUST ABOUT IDENTICAL TO TUE
NIGHT/S...WITH TEENS EXPECTED FOR MOST LOWLANDS AND PERHAPS LOWER
20S FOR THE COALFIELDS.
&&
.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 /20Z MONDAY THROUGH SATURDAY/...
PRIMARILY MVFR STRATUS INTO TONIGHT WITH SOME IFR CIGS/VSBY IN THE
MOUNTAINS AMID PATCHY DZ. SOME BREAKS POSSIBLE ACROSS SE OH AND NE
KY TONIGHT.
AN UPPER LEVEL TROF WILL APPROACH LATE TONIGHT AND COMBINED WITH A
SURFACE WAVE TO THE SE WILL ALLOW SN OVERSPREAD MUCH OF THE
AREA...HEAVIEST ACROSS THE LOWLANDS AND MOUNTAINS. CIGS WILL LOWER
INTO IFR/LIFR ALONG WITH VSBY AS THE SN MOVES IN 09 TO 15Z. SOME
IMPROVEMENT AFTER 15Z AS CIGS/VSBY RISE INTO MVFR AND TRYING TO
SCT OU ACROSS SE OH/NE KY/W WV IN AFTERNOON.
FORECAST CONFIDENCE AND ALTERNATE SCENARIOS THROUGH 18Z
TUESDAY...
FORECAST CONFIDENCE: MEDIUM.
ALTERNATE SCENARIOS: TIMING OF IFR/LIFR CIGS MAY VARY FROM CURRENT FORECAST.
EXPERIMENTAL TABLE OF FLIGHT CATEGORY OBJECTIVELY SHOWS CONSISTENCY
OF WFO FORECAST TO AVAILABLE MODEL INFORMATION:
H = HIGH: TAF CONSISTENT WITH ALL MODELS OR ALL BUT ONE MODEL.
M = MEDIUM: TAF HAS VARYING LEVEL OF CONSISTENCY WITH MODELS.
L = LOW: TAF INCONSISTENT WITH ALL MODELS OR ALL BUT ONE MODEL.
UTC 1HRLY 20 21 22 23 00 01 02 03 04 05 06 07
EST 1HRLY 15 16 17 18 19 20 21 22 23 00 01 02
CRW CONSISTENCY H H H H H H H H H H H H
HTS CONSISTENCY H H H H H H M M M M M H
BKW CONSISTENCY H H H H L L L L L M H H
EKN CONSISTENCY H H H H H L L L L L L L
PKB CONSISTENCY H H H H H H H H H M M H
CKB CONSISTENCY H H H H H H H H H H H H
AFTER 18Z TUESDAY...
IFR POSSIBLE IN SNOW MONDAY NIGHT INTO TUESDAY.
&&
.RLX WATCHES/WARNINGS/ADVISORIES...
WV...WINTER WEATHER ADVISORY FROM 1 AM TO 3 PM EST TUESDAY FOR
WVZ005>011-013>020-024>040-046-047.
OH...NONE.
KY...WINTER WEATHER ADVISORY FROM 1 AM TO 3 PM EST TUESDAY FOR
KYZ103-105.
VA...WINTER WEATHER ADVISORY FROM 1 AM TO 3 PM EST TUESDAY FOR
VAZ003-004.
&&
$$
SYNOPSIS...TRM/RPY/30
NEAR TERM...30
SHORT TERM...50
LONG TERM...RPY
AVIATION...30
AREA FORECAST DISCUSSION
NWS CHARLESTON WV
637 AM EST MON DEC 9 2013
.SYNOPSIS...
A LOW PRESSURE WAVE CROSSES TODAY. A WEAK SYSTEM CROSSES LATE
TONIGHT INTO TUESDAY WITH SOME SNOW EXPECTED. CHILLY DRY HIGH
PRESSURE FOR WEDNESDAY INTO FRIDAY.
&&
.NEAR TERM /THROUGH TONIGHT/...
630 AM UPDATE...
UPDATE TO CANCEL REMAINING WINTER WX ADVISORY AND WARNING FOR
EASTERN MOUNTAINS. A FEW ISOLATED PATCHES OF MAINLY FREEZING
DRIZZLE WITH VERY LIGHT ACCUMULATIONS MAY STILL BE POSSIBLE FOR
ANOTHER HOUR OR SO THIS MORNING ACROSS THE FAR EASTERN PORTIONS OF
THE EASTERN MOUNTAIN COUNTIES.
PREVIOUS DISCUSSION...
MAINLY ZONAL FLOW WILL PREVAIL TODAY...WITH AREAS OF CLEARING
SPREADING FROM WEST TO EAST. MODELS SHOW AN MID TO UPPER AIR VORT
MAX ASSOCIATED WITH AN H5 SHORTWAVE CROSSING THE AREA BY 18
TUESDAY.
LATEST RADAR IMAGES SHOW A BAND OF RAIN SHOWING SIGNS OF BREAKING
UP WITH RAIN DIMINISHING IN INTENSITY. WITH SATURATED
TERRAIN...KEPT FLOOD WATCH FOR THE WESTERN SLOPES OF WV...SOUTHWEST
VA AND SOUTHERN COAL FIELDS AS SOME DECENT PRECIPITATION AMOUNTS...0.5
TO 0.75 INCHES IN 6 HOURS HAVE BEEN REPORTED.
WINTER WEATHER ADVISORIES REMAIN IN EFFECT FROM RALEIGH...NORTH TO
WEBSTER FOR FREEZING RAIN AND SNOW...WHILE WINTER STORM WARNING
REMAINS IN EFFECT FOR POCAHONTAS AND RANDOLPH COUNTIES THROUGH 12Z
MONDAY.
WARM ADVECTION SHOULD CONTINUE THROUGH THE NIGHT...SO HAVE NON-
DIURNAL TEMPERATURES...BASED HEAVILY ON THE RAP AND WRF GUIDANCE.
WENT WITH THE WRF AND THE GFS GUIDANCE FOR TEMPERATURE THROUGH THE
PERIOD.
&&
.SHORT TERM /TUESDAY THROUGH WEDNESDAY NIGHT/...
ACTIVE AT THE OUTSET OF THE PERIOD ON TUESDAY MORNING WITH A
QUICK-HITTING SYSTEM PUSHING ACROSS THE AREA. YET ANOTHER WAVE OF
LOW PRESSURE WILL BE RIDING ALONG THE QUASI-STATIONARY FRONT STILL
TO OUR SOUTHEAST WHICH IS PROGGED TO BE LOCATED NEAR THE TN/NC/GA
AREA AT 12Z TUE. MEANWHILE AN UPPER TROUGH WILL BE PROGRESSING
EASTWARD QUICKLY ACROSS THE LOWER/MID OHIO RIVER VALLEY TUE MORNING.
EXPECT TWO DISTINCT AREAS OF PRECIP AT THE OUTSET...ONE ENTERING THE
SE OHIO ZONES AND THE OTHER PUSHING UP FROM THE SW WITH THE SFC LOW.
THESE SHOULD MERGE OVER THE NORTHEAST ZONES BY MID-LATE MORNING ON
IT/S WAY OUT OF OUR AREA. VARIOUS QPF OUTPUT DEPICTING ROUGHLY
0.1-0.2 INCHES IN GENERAL...WITH SOME HIGHER AMOUNTS PARTICULARLY ON
THE FINER RESOLUTION NAM12. TOUGH CALL ON SNOWFALL AMOUNTS WITH SOME
DIFFERENCES IN TIMING OF THE HIGHEST QPF AND WITH THE SYSTEM BEING
SUCH A FAST-MOVER. A GENERAL INCH OR SO APPEARS REASONABLE FOR MUCH
OF THE LOWLANDS LATE MON NIGHT GOING INTO TUE MORNING. THE AREA
HOWEVER COMES UNDER INFLUENCE OF RIGHT ENTRANCE REGION OF STRONG JET
JUST TO OUR NORTHWEST AROUND THE 12Z TUE TIME FRAME WITH GOOD
UNIDIRECTIONAL SPEED SHEAR. A BIT CONCERNED WITH PROGGED EPV AND
THETA-E LAPSE RATE VALS WITH GOOD SATURATION ABOVE THE COLD
DOME...NOT TO MENTION SOME WEAK ELEVATED CAPE...THAT SOME LOCATIONS
MAY SEE SOME ENHANCEMENT OF SNOWFALL RATES/ACCUMULATIONS IN NARROW
MESOSCALE BANDS THROUGH SLANTWISE AND/OR UPRIGHT CONVECTION.
CONSIDERED AN ADVISORY FOR TUE MORNING...BUT AFTER COLLABORATION
WITH SURROUNDING OFFICES DECIDED TO ALLOW DAY SHIFT ONE MORE LOOK AT
LATEST DATA. DID BUMP UP SNOW AMOUNTS...AGAIN...TO AROUND THE 1-2
INCH RANGE WITH SOME 2-3 ACROSS THE NORTHEAST ZONES. SNOWFALL WILL
PRIMARILY BE CONFINED NEAR THE EASTERN MOUNTAINS BY 18Z TUE WITH
ONLY A SLIGHT CHANCE OF LIGHT SNOW REMAINING BY 00Z WED. ALSO NUDGED
MAX TEMPS DOWN A BIT TUESDAY PER LATEST MOS GUIDANCE AND 925MB TEMPS
SUPPORTING. MANY LOCATIONS TUESDAY WILL STRUGGLE TO REACH THE
FREEZING MARK.
HIGH PRESSURE PUSHES IN FROM THE WEST TUESDAY NIGHT AND WEDNESDAY
WITH RAPIDLY CLEARING SKIES TUESDAY NIGHT WITH HIGH PRESSURE CENTER
LOCATED OVER THE SOUTHERN ZONES BY 12Z WED. CLEARING SKIES AND LIGHT
WINDS WILL ALLOW GOOD COOLING WITH TEENS EXPECTED FOR MOST
LOCATIONS...AND EVEN SOME SINGLE DIGITS POSSIBLE OVER SE OHIO AND OF
COURSE THE EASTERN HIGH COUNTRY. AN UPPER TROUGH WILL PASS BY TO THE
NORTH OF THE FORECAST AREA WEDNESDAY RESULTING IN PERHAPS A FEW MORE
CLOUDS NORTH. BUT OTHERWISE A DRY AND SUNNY...BUT COOL...DAY IS ON
TAP FOR WEDNESDAY. MAX TEMPS GENERALLY IN THE LOW/MID 30S FOR THE
LOWLANDS STILL APPEAR ON TRACK WITH VERY LITTLE CHANGE FROM PREV
FCST. SFC WINDS WILL COME AROUND TO THE SOUTHWEST AS SFC HIGH
CONTINUES TO PUSH OFF TO THE EAST. A QUICK MOVING FRONT WILL PUSH
ACROSS THE AREA WED NIGHT...BUT LITTLE MOISTURE WITH IT RESULTS IN
ONLY A BRIEF INCREASE IN CLOUD COVER AND SOME BREEZY POST-FRONTAL
WINDS WED NIGHT...EXCEPT FOR THE FAR NORTHEAST ZONES WHERE JUST
ENOUGH MOISTURE DEPTH MAY BE ENOUGH TO SQUEEZE OUT A LIGHT SNOW
SHOWER. THUS WILL CARRY SLIGHT CHANCE POPS HERE WED NIGHT. SNOW
ACCUMS WILL NOT BE AN ISSUE HOWEVER...WITH ONLY A DUSTING TO A FEW
TENTHS POSSIBLE. MINS AGAIN WILL BE JUST ABOUT IDENTICAL TO TUE
NIGHT/S...WITH TEENS EXPECTED FOR MOST LOWLANDS AND PERHAPS LOWER
20S FOR THE COALFIELDS.
&&
.LONG TERM /THURSDAY THROUGH SUNDAY/...
STILL JUST WHAT THE DOCTOR ORDERED. A MOSTLY DRY PATTERN
WEDNESDAY NIGHT INTO SATURDAY. HAVE A SLIGHT CHANCE OF SOME
LIGHT SNOW SHOWERS WEDNESDAY NIGHT ACROSS THE NORTHERN WV
MOUNTAINS.
DRY AIR AND THE LONG DECEMBER NIGHTS YIELDS COLD DAWN TEMPERATURES.
DOWN THE ROAD...MOISTURE INCREASES SATURDAY...HAVE SOME CHANCE POPS
BY SATURDAY FOR RAIN AND SNOW. STILL APPEARS NOT A HEAVY EVENT.
&&
.AVIATION /12Z MONDAY THROUGH FRIDAY/...
LIFR CONDITIONS WILL PREVAIL THIS MORNING AS THE LAST AREAS OF
RAIN ASSOCIATED WITH LAST COLD FRONT EXITS EAST OF THE MOUNTAINS
LATE THIS MORNING. PERIODS OF IFR/LIFR VISIBILITIES ARE POSSIBLE
DURING THE PREDAWN HOURS...PERHAPS LASTING UNTIL 14Z AT SOME
PLACES.
ANOTHER ROUND OF SNOW SHOWERS WILL APPROACH FROM THE NORTHWEST
LATER TONIGHT FOR IFR/LIFR CONDITIONS ALOND THE SHOWER.
AREAS OF LIFR CIGS DEVELOPING MAINLY 03Z THROUGH 14Z OVERNIGHT...LIFTING
TO IFR/MVFR FOR REMAINDER OF TAF PERIOD.
FORECAST CONFIDENCE AND ALTERNATE SCENARIOS THROUGH 12Z TUESDAY...
FORECAST CONFIDENCE: MEDIUM.
ALTERNATE SCENARIOS: TIMING OF IFR/LIFR CIGS MAY VARY FROM CURRENT FORECAST.
EXPERIMENTAL TABLE OF FLIGHT CATEGORY OBJECTIVELY SHOWS CONSISTENCY
OF WFO FORECAST TO AVAILABLE MODEL INFORMATION:
H = HIGH: TAF CONSISTENT WITH ALL MODELS OR ALL BUT ONE MODEL.
M = MEDIUM: TAF HAS VARYING LEVEL OF CONSISTENCY WITH MODELS.
L = LOW: TAF INCONSISTENT WITH ALL MODELS OR ALL BUT ONE MODEL.
UTC 1HRLY 11 12 13 14 15 16 17 18 19 20 21 22
EST 1HRLY 06 07 08 09 10 11 12 13 14 15 16 17
CRW CONSISTENCY H H H H H H M M M H H H
HTS CONSISTENCY H H H H H H H H H H H H
BKW CONSISTENCY M M M M M M M M H H H H
EKN CONSISTENCY H H H M M M L H H H H H
PKB CONSISTENCY H M H M M H H H H H H H
CKB CONSISTENCY H H H H H H H H H H H H
AFTER 12Z TUESDAY...
IFR POSSIBLE IN SNOW MONDAY NIGHT INTO TUESDAY.
&&
.EQUIPMENT...
ADDITIONAL PARTS FOR PARKERSBURG ASOS ARE EXPECTED TO ARRIVE MONDAY.
AUTOMATED OBSERVATIONS WILL BE UNAVAILABLE AT TIMES UNTIL THEN.
&&
.RLX WATCHES/WARNINGS/ADVISORIES...
WV...NONE.
OH...NONE.
KY...NONE.
VA...NONE.
&&
$$
SYNOPSIS...ARJ
NEAR TERM...ARJ/50
SHORT TERM...50
LONG TERM...KTB
AVIATION...ARJ
AREA FORECAST DISCUSSION
NWS CHARLESTON WV
548 AM EST MON DEC 9 2013
.SYNOPSIS...
A LOW PRESSURE WAVE CROSSES TODAY. A WEAK SYSTEM CROSSES LATE
TONIGHT INTO TUESDAY WITH SOME SNOW EXPECTED. CHILLY DRY HIGH
PRESSURE FOR WEDNESDAY INTO FRIDAY.
&&
.NEAR TERM /THROUGH TONIGHT/...
MAINLY ZONAL FLOW WILL PREVAIL TODAY...WITH AREAS OF CLEARING
SPREADING FROM WEST TO EAST. MODELS SHOW AN MID TO UPPER AIR VORT
MAX ASSOCIATED WITH AN H5 SHORTWAVE CROSSING THE AREA BY 18
TUESDAY.
LATEST RADAR IMAGES SHOW A BAND OF RAIN SHOWING SIGNS OF BREAKING
UP WITH RAIN DIMINISHING IN INTENSITY. WITH SATURATED
TERRAIN...KEPT FLOOD WATCH FOR THE WESTERN SLOPES OF WV...SOUTHWEST
VA AND SOUTHERN COAL FIELDS AS SOME DECENT PRECIPITATION AMOUNTS...0.5
TO 0.75 INCHES IN 6 HOURS HAVE BEEN REPORTED.
WINTER WEATHER ADVISORIES REMAIN IN EFFECT FROM RALEIGH...NORTH TO
WEBSTER FOR FREEZING RAIN AND SNOW...WHILE WINTER STORM WARNING
REMAINS IN EFFECT FOR POCAHONTAS AND RANDOLPH COUNTIES THROUGH 12Z
MONDAY.
WARM ADVECTION SHOULD CONTINUE THROUGH THE NIGHT...SO HAVE NON-
DIURNAL TEMPERATURES...BASED HEAVILY ON THE RAP AND WRF GUIDANCE.
WENT WITH THE WRF AND THE GFS GUIDANCE FOR TEMPERATURE THROUGH THE
PERIOD.
&&
.SHORT TERM /TUESDAY THROUGH THURSDAY/...
ACTIVE AT THE OUTSET OF THE PERIOD ON TUESDAY MORNING WITH A
QUICK-HITTING SYSTEM PUSHING ACROSS THE AREA. YET ANOTHER WAVE OF
LOW PRESSURE WILL BE RIDING ALONG THE QUASI-STATIONARY FRONT STILL
TO OUR SOUTHEAST WHICH IS PROGGED TO BE LOCATED NEAR THE TN/NC/GA
AREA AT 12Z TUE. MEANWHILE AN UPPER TROUGH WILL BE PROGRESSING
EASTWARD QUICKLY ACROSS THE LOWER/MID OHIO RIVER VALLEY TUE MORNING.
EXPECT TWO DISTINCT AREAS OF PRECIP AT THE OUTSET...ONE ENTERING THE
SE OHIO ZONES AND THE OTHER PUSHING UP FROM THE SW WITH THE SFC LOW.
THESE SHOULD MERGE OVER THE NORTHEAST ZONES BY MID-LATE MORNING ON
IT/S WAY OUT OF OUR AREA. VARIOUS QPF OUTPUT DEPICTING ROUGHLY
0.1-0.2 INCHES IN GENERAL...WITH SOME HIGHER AMOUNTS PARTICULARLY ON
THE FINER RESOLUTION NAM12. TOUGH CALL ON SNOWFALL AMOUNTS WITH SOME
DIFFERENCES IN TIMING OF THE HIGHEST QPF AND WITH THE SYSTEM BEING
SUCH A FAST-MOVER. A GENERAL INCH OR SO APPEARS REASONABLE FOR MUCH
OF THE LOWLANDS LATE MON NIGHT GOING INTO TUE MORNING. THE AREA
HOWEVER COMES UNDER INFLUENCE OF RIGHT ENTRANCE REGION OF STRONG JET
JUST TO OUR NORTHWEST AROUND THE 12Z TUE TIME FRAME WITH GOOD
UNIDIRECTIONAL SPEED SHEAR. A BIT CONCERNED WITH PROGGED EPV AND
THETA-E LAPSE RATE VALS WITH GOOD SATURATION ABOVE THE COLD
DOME...NOT TO MENTION SOME WEAK ELEVATED CAPE...THAT SOME LOCATIONS
MAY SEE SOME ENHANCEMENT OF SNOWFALL RATES/ACCUMULATIONS IN NARROW
MESOSCALE BANDS THROUGH SLANTWISE AND/OR UPRIGHT CONVECTION.
CONSIDERED AN ADVISORY FOR TUE MORNING...BUT AFTER COLLABORATION
WITH SURROUNDING OFFICES DECIDED TO ALLOW DAY SHIFT ONE MORE LOOK AT
LATEST DATA. DID BUMP UP SNOW AMOUNTS...AGAIN...TO AROUND THE 1-2
INCH RANGE WITH SOME 2-3 ACROSS THE NORTHEAST ZONES. SNOWFALL WILL
PRIMARILY BE CONFINED NEAR THE EASTERN MOUNTAINS BY 18Z TUE WITH
ONLY A SLIGHT CHANCE OF LIGHT SNOW REMAINING BY 00Z WED. ALSO NUDGED
MAX TEMPS DOWN A BIT TUESDAY PER LATEST MOS GUIDANCE AND 925MB TEMPS
SUPPORTING. MANY LOCATIONS TUESDAY WILL STRUGGLE TO REACH THE
FREEZING MARK.
HIGH PRESSURE PUSHES IN FROM THE WEST TUESDAY NIGHT AND WEDNESDAY
WITH RAPIDLY CLEARING SKIES TUESDAY NIGHT WITH HIGH PRESSURE CENTER
LOCATED OVER THE SOUTHERN ZONES BY 12Z WED. CLEARING SKIES AND LIGHT
WINDS WILL ALLOW GOOD COOLING WITH TEENS EXPECTED FOR MOST
LOCATIONS...AND EVEN SOME SINGLE DIGITS POSSIBLE OVER SE OHIO AND OF
COURSE THE EASTERN HIGH COUNTRY. AN UPPER TROUGH WILL PASS BY TO THE
NORTH OF THE FORECAST AREA WEDNESDAY RESULTING IN PERHAPS A FEW MORE
CLOUDS NORTH. BUT OTHERWISE A DRY AND SUNNY...BUT COOL...DAY IS ON
TAP FOR WEDNESDAY. MAX TEMPS GENERALLY IN THE LOW/MID 30S FOR THE
LOWLANDS STILL APPEAR ON TRACK WITH VERY LITTLE CHANGE FROM PREV
FCST. SFC WINDS WILL COME AROUND TO THE SOUTHWEST AS SFC HIGH
CONTINUES TO PUSH OFF TO THE EAST. A QUICK MOVING FRONT WILL PUSH
ACROSS THE AREA WED NIGHT...BUT LITTLE MOISTURE WITH IT RESULTS IN
ONLY A BRIEF INCREASE IN CLOUD COVER AND SOME BREEZY POST-FRONTAL
WINDS WED NIGHT...EXCEPT FOR THE FAR NORTHEAST ZONES WHERE JUST
ENOUGH MOISTURE DEPTH MAY BE ENOUGH TO SQUEEZE OUT A LIGHT SNOW
SHOWER. THUS WILL CARRY SLIGHT CHANCE POPS HERE WED NIGHT. SNOW
ACCUMS WILL NOT BE AN ISSUE HOWEVER...WITH ONLY A DUSTING TO A FEW
TENTHS POSSIBLE. MINS AGAIN WILL BE JUST ABOUT IDENTICAL TO TUE
NIGHT/S...WITH TEENS EXPECTED FOR MOST LOWLANDS AND PERHAPS LOWER
20S FOR THE COALFIELDS.
&&
.LONG TERM /THURSDAY NIGHT THROUGH SUNDAY/...
STILL JUST WHAT THE DOCTOR ORDERED. A MOSTLY DRY PATTERN
WEDNESDAY NIGHT INTO SATURDAY. HAVE A SLIGHT CHANCE OF SOME
LIGHT SNOW SHOWERS WEDNESDAY NIGHT ACROSS THE NORTHERN WV
MOUNTAINS.
DRY AIR AND THE LONG DECEMBER NIGHTS YIELDS COLD DAWN TEMPERATURES.
DOWN THE ROAD...MOISTURE INCREASES SATURDAY...HAVE SOME CHANCE POPS
BY SATURDAY FOR RAIN AND SNOW. STILL APPEARS NOT A HEAVY EVENT.
&&
.AVIATION /12Z MONDAY THROUGH FRIDAY/...
LIFR CONDITIONS WILL PREVAIL THIS MORNING AS THE LAST AREAS OF
RAIN ASSOCIATED WITH LAST COLD FRONT EXITS EAST OF THE MOUNTAINS
LATE THIS MORNING. PERIODS OF IFR/LIFR VISIBILITIES ARE POSSIBLE
DURING THE PREDAWN HOURS...PERHAPS LASTING UNTIL 14Z AT SOME
PLACES.
ANOTHER ROUND OF SNOW SHOWERS WILL APPROACH FROM THE NORTHWEST
LATER TONIGHT FOR IFR/LIFR CONDITIONS ALOND THE SHOWER.
AREAS OF LIFR CIGS DEVELOPING MAINLY 03Z THROUGH 14Z OVERNIGHT...LIFTING
TO IFR/MVFR FOR REMAINDER OF TAF PERIOD.
FORECAST CONFIDENCE AND ALTERNATE SCENARIOS THROUGH 12Z TUESDAY...
FORECAST CONFIDENCE: MEDIUM.
ALTERNATE SCENARIOS: TIMING OF IFR/LIFR CIGS MAY VARY FROM CURRENT FORECAST.
EXPERIMENTAL TABLE OF FLIGHT CATEGORY OBJECTIVELY SHOWS CONSISTENCY
OF WFO FORECAST TO AVAILABLE MODEL INFORMATION:
H = HIGH: TAF CONSISTENT WITH ALL MODELS OR ALL BUT ONE MODEL.
M = MEDIUM: TAF HAS VARYING LEVEL OF CONSISTENCY WITH MODELS.
L = LOW: TAF INCONSISTENT WITH ALL MODELS OR ALL BUT ONE MODEL.
UTC 1HRLY 11 12 13 14 15 16 17 18 19 20 21 22
EST 1HRLY 06 07 08 09 10 11 12 13 14 15 16 17
CRW CONSISTENCY H H H H H H M M M H H H
HTS CONSISTENCY H H H H H H H H H H H H
BKW CONSISTENCY M M M M M M M M H H H H
EKN CONSISTENCY H H H M M M L H H H H H
PKB CONSISTENCY H M H M M H H H H H H H
CKB CONSISTENCY H H H H H H H H H H H H
AFTER 12Z TUESDAY...
IFR POSSIBLE IN SNOW MONDAY NIGHT INTO TUESDAY.
&&
&&
.EQUIPMENT...
ADDITIONAL PARTS FOR PARKERSBURG ASOS ARE EXPECTED TO ARRIVE MONDAY.
AUTOMATED OBSERVATIONS WILL BE UNAVAILABLE AT TIMES UNTIL THEN.
&&
.RLX WATCHES/WARNINGS/ADVISORIES...
WV...WINTER STORM WARNING UNTIL 7 AM EST THIS MORNING FOR WVZ035-
036-046-047.
WINTER WEATHER ADVISORY UNTIL 7 AM EST THIS MORNING FOR WVZ037-
038.
OH...NONE.
KY...NONE.
VA...NONE.
&&
$$
SYNOPSIS...ARJ
NEAR TERM...50
SHORT TERM...TRM
LONG TERM...KTB
AVIATION...ARJ
HYDROLOGY...
EQUIPMENT...
AREA FORECAST DISCUSSION
NWS CHARLESTON WV
504 AM EST MON DEC 9 2013
.SYNOPSIS...
A LOW PRESSURE WAVE CROSSES TODAY. A WEAK SYSTEM CROSSES LATE
TONIGHT INTO TUESDAY WITH SOME SNOW EXPECTED. CHILLY DRY HIGH
PRESSURE FOR WEDNESDAY INTO FRIDAY.
&&
.NEAR TERM /THROUGH TONIGHT/...
MAINLY ZONAL FLOW WILL PREVAIL TODAY...WITH AREAS OF CLEARING
SPREADING FROM WEST TO EAST. MODELS SHOW AN MID TO UPPER AIR VORT
MAX ASSOCIATED WITH AN H5 SHORTWAVE CROSSING THE AREA BY 18
TUESDAY.
LATEST RADAR IMAGES SHOW A BAND OF RAIN SHOWING SIGNS OF BREAKING
UP WITH RAIN DIMINISHING IN INTENSITY. WITH SATURATED
TERRAIN...KEPT FLOOD WATCH FOR THE WESTERN SLOPES OF WV...SOUTHWEST
VA AND SOUTHERN COAL FIELDS AS SOME DECENT PRECIPITATION AMOUNTS...0.5
TO 0.75 INCHES IN 6 HOURS HAVE BEEN REPORTED.
WINTER WEATHER ADVISORIES REMAIN IN EFFECT FROM RALEIGH...NORTH TO
WEBSTER FOR FREEZING RAIN AND SNOW...WHILE WINTER STORM WARNING
REMAINS IN EFFECT FOR POCAHONTAS AND RANDOLPH COUNTIES THROUGH 12Z
MONDAY.
WARM ADVECTION SHOULD CONTINUE THROUGH THE NIGHT...SO HAVE NON-
DIURNAL TEMPERATURES...BASED HEAVILY ON THE RAP AND WRF GUIDANCE.
WENT WITH THE WRF AND THE GFS GUIDANCE FOR TEMPERATURE THROUGH THE
PERIOD.
&&
.SHORT TERM /TUESDAY THROUGH WEDNESDAY NIGHT/...
ACTIVE AT THE OUTSET OF THE PERIOD ON TUESDAY MORNING WITH A
QUICK-HITTING SYSTEM PUSHING ACROSS THE AREA. YET ANOTHER WAVE OF
LOW PRESSURE WILL BE RIDING ALONG THE QUASI-STATIONARY FRONT STILL
TO OUR SOUTHEAST WHICH IS PROGGED TO BE LOCATED NEAR THE TN/NC/GA
AREA AT 12Z TUE. MEANWHILE AN UPPER TROUGH WILL BE PROGRESSING
EASTWARD QUICKLY ACROSS THE LOWER/MID OHIO RIVER VALLEY TUE MORNING.
EXPECT TWO DISTINCT AREAS OF PRECIP AT THE OUTSET...ONE ENTERING THE
SE OHIO ZONES AND THE OTHER PUSHING UP FROM THE SW WITH THE SFC LOW.
THESE SHOULD MERGE OVER THE NORTHEAST ZONES BY MID-LATE MORNING ON
IT/S WAY OUT OF OUR AREA. VARIOUS QPF OUTPUT DEPICTING ROUGHLY
0.1-0.2 INCHES IN GENERAL...WITH SOME HIGHER AMOUNTS PARTICULARLY ON
THE FINER RESOLUTION NAM12. TOUGH CALL ON SNOWFALL AMOUNTS WITH SOME
DIFFERENCES IN TIMING OF THE HIGHEST QPF AND WITH THE SYSTEM BEING
SUCH A FAST-MOVER. A GENERAL INCH OR SO APPEARS REASONABLE FOR MUCH
OF THE LOWLANDS LATE MON NIGHT GOING INTO TUE MORNING. THE AREA
HOWEVER COMES UNDER INFLUENCE OF RIGHT ENTRANCE REGION OF STRONG JET
JUST TO OUR NORTHWEST AROUND THE 12Z TUE TIME FRAME WITH GOOD
UNIDIRECTIONAL SPEED SHEAR. A BIT CONCERNED WITH PROGGED EPV AND
THETA-E LAPSE RATE VALS WITH GOOD SATURATION ABOVE THE COLD
DOME...NOT TO MENTION SOME WEAK ELEVATED CAPE...THAT SOME LOCATIONS
MAY SEE SOME ENHANCEMENT OF SNOWFALL RATES/ACCUMULATIONS IN NARROW
MESOSCALE BANDS THROUGH SLANTWISE AND/OR UPRIGHT CONVECTION.
CONSIDERED AN ADVISORY FOR TUE MORNING...BUT AFTER COLLABORATION
WITH SURROUNDING OFFICES DECIDED TO ALLOW DAY SHIFT ONE MORE LOOK AT
LATEST DATA. DID BUMP UP SNOW AMOUNTS...AGAIN...TO AROUND THE 1-2
INCH RANGE WITH SOME 2-3 ACROSS THE NORTHEAST ZONES. SNOWFALL WILL
PRIMARILY BE CONFINED NEAR THE EASTERN MOUNTAINS BY 18Z TUE WITH
ONLY A SLIGHT CHANCE OF LIGHT SNOW REMAINING BY 00Z WED. ALSO NUDGED
MAX TEMPS DOWN A BIT TUESDAY PER LATEST MOS GUIDANCE AND 925MB TEMPS
SUPPORTING. MANY LOCATIONS TUESDAY WILL STRUGGLE TO REACH THE
FREEZING MARK.
HIGH PRESSURE PUSHES IN FROM THE WEST TUESDAY NIGHT AND WEDNESDAY
WITH RAPIDLY CLEARING SKIES TUESDAY NIGHT WITH HIGH PRESSURE CENTER
LOCATED OVER THE SOUTHERN ZONES BY 12Z WED. CLEARING SKIES AND LIGHT
WINDS WILL ALLOW GOOD COOLING WITH TEENS EXPECTED FOR MOST
LOCATIONS...AND EVEN SOME SINGLE DIGITS POSSIBLE OVER SE OHIO AND OF
COURSE THE EASTERN HIGH COUNTRY. AN UPPER TROUGH WILL PASS BY TO THE
NORTH OF THE FORECAST AREA WEDNESDAY RESULTING IN PERHAPS A FEW MORE
CLOUDS NORTH. BUT OTHERWISE A DRY AND SUNNY...BUT COOL...DAY IS ON
TAP FOR WEDNESDAY. MAX TEMPS GENERALLY IN THE LOW/MID 30S FOR THE
LOWLANDS STILL APPEAR ON TRACK WITH VERY LITTLE CHANGE FROM PREV
FCST. SFC WINDS WILL COME AROUND TO THE SOUTHWEST AS SFC HIGH
CONTINUES TO PUSH OFF TO THE EAST. A QUICK MOVING FRONT WILL PUSH
ACROSS THE AREA WED NIGHT...BUT LITTLE MOISTURE WITH IT RESULTS IN
ONLY A BRIEF INCREASE IN CLOUD COVER AND SOME BREEZY POST-FRONTAL
WINDS WED NIGHT...EXCEPT FOR THE FAR NORTHEAST ZONES WHERE JUST
ENOUGH MOISTURE DEPTH MAY BE ENOUGH TO SQUEEZE OUT A LIGHT SNOW
SHOWER. THUS WILL CARRY SLIGHT CHANCE POPS HERE WED NIGHT. SNOW
ACCUMS WILL NOT BE AN ISSUE HOWEVER...WITH ONLY A DUSTING TO A FEW
TENTHS POSSIBLE. MINS AGAIN WILL BE JUST ABOUT IDENTICAL TO TUE
NIGHT/S...WITH TEENS EXPECTED FOR MOST LOWLANDS AND PERHAPS LOWER
20S FOR THE COALFIELDS.
&&
.LONG TERM /THURSDAY THROUGH SUNDAY/...
STILL JUST WHAT THE DOCTOR ORDERED. A MOSTLY DRY PATTERN
WEDNESDAY NIGHT INTO SATURDAY. HAVE A SLIGHT CHANCE OF SOME
LIGHT SNOW SHOWERS WEDNESDAY NIGHT ACROSS THE NORTHERN WV
MOUNTAINS.
DRY AIR AND THE LONG DECEMBER NIGHTS YIELDS COLD DAWN TEMPERATURES.
DOWN THE ROAD...MOISTURE INCREASES SATURDAY...HAVE SOME CHANCE POPS
BY SATURDAY FOR RAIN AND SNOW. STILL APPEARS NOT A HEAVY EVENT.
&&
.AVIATION /06Z MONDAY THROUGH FRIDAY/...
PERHAPS THE LAST BAND OF LIGHT RAIN UNDER 35 DEGREES MOVING
SLOWLY EAST THROUGH AT LEAST 09Z. THEN...AREAS OF RAIN ARE
EXPECTED TO EXIT THE EASTERN MOUNTAINS. HOWEVER...PERIODS OF
IFR/LIFR WILL BE COMMON UNDER AREAS OF RAIN. A LOW LEVEL DECK
AROUND 500 FEET IS EXPECTED TO FORM OR CONTINUE ACROSS MOST SITES
THROUGH THE PREDAWN HOURS.
AREAS OF LIFR CIGS DEVELOPING MAINLY 03Z THROUGH 14Z OVERNIGHT...LIFTING
TO IFR/MVFR FOR REMAINDER OF TAF PERIOD.
FORECAST CONFIDENCE AND ALTERNATE SCENARIOS THROUGH 06Z TUESDAY...
FORECAST CONFIDENCE: MEDIUM.
ALTERNATE SCENARIOS: TIMING OF IFR/LIFR CIGS MAY VARY FROM CURRENT FORECAST.
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 MON 12/09/13
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 H M M M M M H H H H H
HTS CONSISTENCY M M H H H H H M H H H H
BKW CONSISTENCY H H M M M M M M M M M M
EKN CONSISTENCY M M M M M M M M M L L L
PKB CONSISTENCY M H M H H H L L L H H H
CKB CONSISTENCY H H H H H H M M M M M H
AFTER 06Z TUESDAY...
IFR POSSIBLE IN SNOW MONDAY NIGHT INTO TUESDAY.
&&
.EQUIPMENT...
ADDITIONAL PARTS FOR PARKERSBURG ASOS ARE EXPECTED TO ARRIVE MONDAY.
AUTOMATED OBSERVATIONS WILL BE UNAVAILABLE AT TIMES UNTIL THEN.
&&
.RLX WATCHES/WARNINGS/ADVISORIES...
WV...WINTER STORM WARNING UNTIL 7 AM EST THIS MORNING FOR WVZ035-
036-046-047.
WINTER WEATHER ADVISORY UNTIL 7 AM EST THIS MORNING FOR WVZ037-
038.
OH...NONE.
KY...NONE.
VA...NONE.
&&
$$
SYNOPSIS...ARJ/50
NEAR TERM...ARJ
SHORT TERM...50
LONG TERM...KTB
AVIATION...ARJ
AREA FORECAST DISCUSSION
NWS CHARLESTON WV
419 AM EST MON DEC 9 2013
.SYNOPSIS...
A LOW PRESSURE WAVE CROSSES TODAY. A WEAK SYSTEM CROSSES LATE
TONIGHT INTO TUESDAY. CHILLY DRY HIGH PRESSURE FOR WEDNESDAY INTO
FRIDAY.
&&
.NEAR TERM /THROUGH TONIGHT/...
MAINLY ZONAL FLOW WILL PREVAIL TODAY...WITH AREAS OF CLEARING
SPREADING FROM WEST TO EAST. MODELS SHOW AN MID TO UPPER AIR VORT
MAX ASSOCIATED WITH AN H5 SHORTWAVE CROSSING THE AREA BY 18
TUESDAY.
LATEST RADAR IMAGES SHOW A BAND OF RAIN SHOWING SIGNS OF BREAKING
UP WITH RAIN DIMINISHING IN INTENSITY. WITH SATURATED
TERRAIN...KEPT FLOOD WATCH FOR THE WESTERN SLOPES OF WV...SOUTHWEST
VA AND SOUTHERN COAL FIELDS AS SOME DECENT PRECIPITATION AMOUNTS...0.5
TO 0.75 INCHES IN 6 HOURS HAVE BEEN REPORTED.
WINTER WEATHER ADVISORIES REMAIN IN EFFECT FROM RALEIGH...NORTH TO
WEBSTER FOR FREEZING RAIN AND SNOW...WHILE WINTER STORM WARNING
REMAINS IN EFFECT FOR POCAHONTAS AND RANDOLPH COUNTIES THROUGH 12Z
MONDAY.
WARM ADVECTION SHOULD CONTINUE THROUGH THE NIGHT...SO HAVE NON-
DIURNAL TEMPERATURES...BASED HEAVILY ON THE RAP AND WRF GUIDANCE.
WENT WITH THE WRF AND THE GFS GUIDANCE FOR TEMPERATURE THROUGH THE
PERIOD.
&&
.SHORT TERM /TUESDAY THROUGH THURSDAY/...
UPPER LEVEL SW FLOW FINALLY FLATTENS...BECOMING MORE ZONAL...IN THE
WAKE OF A S/W TROUGH THAT CROSSES TUE. SYSTEM IN THE NEAR TERM IS
ABOUT EXODUS BY 00Z TUE...THE START OF THE SHORT TERM...WITH PERHAPS
LIGHT UPSLOPE PRECIPITATION WINDING DOWN. WHILE NOT AS MOISTURE
RICH AS PREVIOUS SYSTEMS...JET DYNAMICS AND S/W FORCING IN THE
BAROCLINIC ZONE SHOULD GENERATE A QUICK HITTING BAND OF
PRECIPITATION THROUGH THE MIDDLE OHIO VALLEY EARLY TUE MORNING.
ANOTHER BAND BRUSHES THE CENTRAL APPALACHIANS AS A SFC WAVE MOVES NE
ALONG THE FRONT WHICH WILL BE OVER THE CAROLINAS AT THAT TIME.
COLDER AIR MOVING IN MON NT WILL DRIVE H85 TEMPERATURES TO -6C TO
-10C N BY TUE AFTERNOON...SO THE PRECIPITATION WILL TAKE THE FORM OF
SNOW...SAVE FOR MIXED PRECIPITATION EARLY ON OVER THE CENTRAL
APPALACHIANS.
ANY UPSLOPE PRECIPITATION IN THE WAKE OF THIS EVENT TUE AFTERNOON IS
BRIEF...AND HIGH PRESSURE BUILDS IN FOR A DRY AND COLD TUE NT...AND
THEN HANGS ON FOR A DRY WED.
USED ADJMET AND NAM FOR TEMPERATURES IN COLD ADVECTION MON
NT...BLENDED IN ADJMET FOR HIGHS TUE AND BIAS CORRECTED ADJMET FOR
LOWS TUE NT. BLENDED IN BIAS CORRECTED ADJMEX FOR HIGHS WED.
OVERALL NO MAJOR CHANGES.
&&
.LONG TERM /THURSDAY NIGHT THROUGH SUNDAY/...
STILL JUST WHAT THE DOCTOR ORDERED. A MOSTLY DRY PATTERN
WEDNESDAY NIGHT INTO SATURDAY. HAVE A SLIGHT CHANCE OF SOME
LIGHT SNOW SHOWERS WEDNESDAY NIGHT ACROSS THE NORTHERN WV
MOUNTAINS.
DRY AIR AND THE LONG DECEMBER NIGHTS YIELDS COLD DAWN TEMPERATURES.
DOWN THE ROAD...MOISTURE INCREASES SATURDAY...HAVE SOME CHANCE POPS
BY SATURDAY FOR RAIN AND SNOW. STILL APPEARS NOT A HEAVY EVENT.
&&
.AVIATION /09Z MONDAY THROUGH FRIDAY/...
PERHAPS THE LAST BAND OF LIGHT RAIN UNDER 35 DEGREES MOVING
SLOWLY EAST THROUGH AT LEAST 09Z. THEN...AREAS OF RAIN ARE
EXPECTED TO EXIT THE EASTERN MOUNTAINS. HOWEVER...PERIODS OF
IFR/LIFR WILL BE COMMON UNDER AREAS OF RAIN. A LOW LEVEL DECK
AROUND 500 FEET IS EXPECTED TO FORM OR CONTINUE ACROSS MOST SITES
THROUGH THE PREDAWN HOURS.
AREAS OF LIFR CIGS DEVELOPING MAINLY 03Z THROUGH 14Z OVERNIGHT...LIFTING
TO IFR/MVFR FOR REMAINDER OF TAF PERIOD.
FORECAST CONFIDENCE AND ALTERNATE SCENARIOS THROUGH 06Z TUESDAY...
FORECAST CONFIDENCE: MEDIUM.
ALTERNATE SCENARIOS: TIMING OF IFR/LIFR CIGS MAY VARY FROM CURRENT FORECAST.
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 MON 12/09/13
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 H M M M M M H H H H H
HTS CONSISTENCY M M H H H H H M H H H H
BKW CONSISTENCY H H M M M M M M M M M M
EKN CONSISTENCY M M M M M M M M M L L L
PKB CONSISTENCY M H M H H H L L L H H H
CKB CONSISTENCY H H H H H H M M M M M H
AFTER 06Z TUESDAY...
IFR POSSIBLE IN SNOW MONDAY NIGHT INTO TUESDAY.
&&
.HYDROLOGY...
THE LAST OF THE RIVER FLOOD WARNINGS AT BELINGTON ASSOCIATED WITH
THE RAINFALL LAST THURSDAY AND FRIDAY...IS GONE.
HAVE FLOOD WATCH FOR MUCH OF THE WV LOWLANDS AND INTO NE KY AS MORE
RAINFALL IS EXPECTED TONIGHT INTO MONDAY...WHICH MAY CAUSE
ADDITIONAL RISES ON RIVERS. THIS ADDITIONAL RAIN MAY ALSO CAUSE
FLOODING ALONG SMALL CREEKS AND STREAMS. WILL NEED TO MONITOR TRENDS
TONIGHT FOR WHERE THE BAND OF HEAVIEST PRECIPITATION SETS UP...AND
THUS WHERE THE AREA OF HIGHEST CONCERN IS.
&&
.EQUIPMENT...
ADDITIONAL PARTS FOR PARKERSBURG ASOS ARE EXPECTED TO ARRIVE MONDAY.
AUTOMATED OBSERVATIONS WILL BE UNAVAILABLE AT TIMES UNTIL THEN.
&&
.RLX WATCHES/WARNINGS/ADVISORIES...
WV...WINTER STORM WARNING UNTIL 7 AM EST THIS MORNING FOR WVZ035-
036-046-047.
WINTER WEATHER ADVISORY UNTIL 7 AM EST THIS MORNING FOR WVZ037-
038.
OH...NONE.
KY...NONE.
VA...NONE.
&&
$$
SYNOPSIS...KTB/ARJ/TRM/MZ
NEAR TERM...ARJ
SHORT TERM...TRM
LONG TERM...KTB
AVIATION...ARJ
HYDROLOGY...
EQUIPMENT...
AREA FORECAST DISCUSSION
NWS CHARLESTON WV
107 AM EST MON DEC 9 2013
.SYNOPSIS...
WARM FRONT LIFTS NORTH INTO TONIGHT. A LOW PRESSURE WAVE CROSSES
LATER TONIGHT INTO MONDAY. A WEAK SYSTEM CROSSES LATE MONDAY NIGHT
INTO TUESDAY. CHILLY DRY HIGH PRESSURE FOR WEDNESDAY INTO FRIDAY.
&&
.NEAR TERM /THROUGH TODAY/...
POPS AND WEATHER GRIDS REMAIN ON TRACK AS THE LAST BAND OF RAIN
GRADUALLY MOVE EAST TOWARDS THE MOUNTAINS. TWEAKED SFC WINDS
FOLLOWING THE LATEST SFC OBS AND THE RUC PROJECTION UP TO 12
HOURS.
A BAND OF RAIN...SHOW SIGNS OF BREAKING UP WITH RAIN DIMINISHING
IN INTENSITY. WITH SATURATED TERRAIN...KEPT FLOOD WATCH FOR THE
WESTERN SLOPES OF WV...SOUTHWEST VA AND SOUTHERN COAL FIELDS AS
SOME DECENT PRECIPITATION AMOUNTS...0.5 TO 0.75 INCHES IN 6 HOURS
HAVE BEEN REPORTED.
WINTER WEATHER ADVISORIES REMAIN IN EFFECT FROM RALEIGH...NORTH TO
WEBSTER FOR FREEZING RAIN AND SNOW...WHILE WINTER STORM WARNING
REMAINS IN EFFECT FOR POCAHONTAS AND RANDOLPH COUNTIES THROUGH 12Z
MONDAY.
WARM ADVECTION SHOULD CONTINUE THROUGH THE NIGHT...SO HAVE NON-
DIURNAL TEMPERATURES...BASED HEAVILY ON THE RAP AND WRF GUIDANCE.
&&
.SHORT TERM /TONIGHT THROUGH WEDNESDAY/...
UPPER LEVEL SW FLOW FINALLY FLATTENS...BECOMING MORE ZONAL...IN THE
WAKE OF A S/W TROUGH THAT CROSSES TUE. SYSTEM IN THE NEAR TERM IS
ABOUT EXODUS BY 00Z TUE...THE START OF THE SHORT TERM...WITH PERHAPS
LIGHT UPSLOPE PRECIPITATION WINDING DOWN. WHILE NOT AS MOISTURE
RICH AS PREVIOUS SYSTEMS...JET DYNAMICS AND S/W FORCING IN THE
BAROCLINIC ZONE SHOULD GENERATE A QUICK HITTING BAND OF
PRECIPITATION THROUGH THE MIDDLE OHIO VALLEY EARLY TUE MORNING.
ANOTHER BAND BRUSHES THE CENTRAL APPALACHIANS AS A SFC WAVE MOVES NE
ALONG THE FRONT WHICH WILL BE OVER THE CAROLINAS AT THAT TIME.
COLDER AIR MOVING IN MON NT WILL DRIVE H85 TEMPERATURES TO -6C TO
-10C N BY TUE AFTERNOON...SO THE PRECIPITATION WILL TAKE THE FORM OF
SNOW...SAVE FOR MIXED PRECIPITATION EARLY ON OVER THE CENTRAL
APPALACHIANS.
ANY UPSLOPE PRECIPITATION IN THE WAKE OF THIS EVENT TUE AFTERNOON IS
BRIEF...AND HIGH PRESSURE BUILDS IN FOR A DRY AND COLD TUE NT...AND
THEN HANGS ON FOR A DRY WED.
USED ADJMET AND NAM FOR TEMPERATURES IN COLD ADVECTION MON
NT...BLENDED IN ADJMET FOR HIGHS TUE AND BIAS CORRECTED ADJMET FOR
LOWS TUE NT. BLENDED IN BIAS CORRECTED ADJMEX FOR HIGHS WED.
OVERALL NO MAJOR CHANGES.
&&
.LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY/...
STILL JUST WHAT THE DOCTOR ORDERED. A MOSTLY DRY PATTERN
WEDNESDAY NIGHT INTO SATURDAY. HAVE A SLIGHT CHANCE OF SOME
LIGHT SNOW SHOWERS WEDNESDAY NIGHT ACROSS THE NORTHERN WV
MOUNTAINS.
DRY AIR AND THE LONG DECEMBER NIGHTS YIELDS COLD DAWN TEMPERATURES.
DOWN THE ROAD...MOISTURE INCREASES SATURDAY...HAVE SOME CHANCE POPS
BY SATURDAY FOR RAIN AND SNOW. STILL APPEARS NOT A HEAVY EVENT.
&&
.AVIATION /06Z MONDAY THROUGH FRIDAY/...
PERHAPS THE LAST BAND OF LIGHT RAIN UNDER 35 DEGREES MOVING
SLOWLY EAST THROUGH AT LEAST 09Z. THEN...AREAS OF RAIN ARE
EXPECTED TO EXIT THE EASTERN MOUNTAINS. HOWEVER...PERIODS OF
IFR/LIFR WILL BE COMMON UNDER AREAS OF RAIN. A LOW LEVEL DECK
AROUND 500 FEET IS EXPECTED TO FORM OR CONTINUE ACROSS MOST SITES
THROUGH THE PREDAWN HOURS.
AREAS OF LIFR CIGS DEVELOPING MAINLY 03Z THROUGH 14Z OVERNIGHT...LIFTING
TO IFR/MVFR FOR REMAINDER OF TAF PERIOD.
FORECAST CONFIDENCE AND ALTERNATE SCENARIOS THROUGH 06Z TUESDAY...
FORECAST CONFIDENCE: MEDIUM.
ALTERNATE SCENARIOS: TIMING OF IFR/LIFR CIGS MAY VARY FROM CURRENT FORECAST.
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 MON 12/09/13
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 M M H H M M M M M H H H
HTS CONSISTENCY H H H H H H H H H H H H
BKW CONSISTENCY M M H H M M M H H M H M
EKN CONSISTENCY M M M M M M M M M M M L
PKB CONSISTENCY H H M H H H H H L L L H
CKB CONSISTENCY M H H M M M M M H M M M
AFTER 06Z TUESDAY...
IFR POSSIBLE IN SNOW MONDAY NIGHT INTO TUESDAY.
&&
.HYDROLOGY...
THE LAST OF THE RIVER FLOOD WARNINGS AT BELINGTON ASSOCIATED WITH
THE RAINFALL LAST THURSDAY AND FRIDAY...IS GONE.
HAVE FLOOD WATCH FOR MUCH OF THE WV LOWLANDS AND INTO NE KY AS MORE
RAINFALL IS EXPECTED TONIGHT INTO MONDAY...WHICH MAY CAUSE
ADDITIONAL RISES ON RIVERS. THIS ADDITIONAL RAIN MAY ALSO CAUSE
FLOODING ALONG SMALL CREEKS AND STREAMS. WILL NEED TO MONITOR TRENDS
TONIGHT FOR WHERE THE BAND OF HEAVIEST PRECIPITATION SETS UP...AND
THUS WHERE THE AREA OF HIGHEST CONCERN IS.
&&
.EQUIPMENT...
ADDITIONAL PARTS FOR PARKERSBURG ASOS ARE EXPECTED TO ARRIVE MONDAY.
AUTOMATED OBSERVATIONS WILL BE UNAVAILABLE AT TIMES UNTIL THEN.
&&
.RLX WATCHES/WARNINGS/ADVISORIES...
WV...FLOOD WATCH THROUGH THIS AFTERNOON FOR WVZ005-006-013>016-018-
020-024>040.
WINTER WEATHER ADVISORY UNTIL 7 AM EST THIS MORNING FOR WVZ037-
038.
WINTER STORM WARNING UNTIL 7 AM EST THIS MORNING FOR WVZ035-
036-046-047.
OH...NONE.
KY...FLOOD WATCH THROUGH THIS AFTERNOON FOR KYZ105.
VA...FLOOD WATCH THROUGH THIS AFTERNOON FOR VAZ003-004.
&&
$$
SYNOPSIS...KTB/TRM/MZ
NEAR TERM...ARJ/MZ/SL
SHORT TERM...TRM
LONG TERM...KTB
AVIATION...ARJ
HYDROLOGY...
EQUIPMENT...
AREA FORECAST DISCUSSION
NWS PORTLAND OR
1005 AM PST MON DEC 9 2013
.SYNOPSIS...LOWER PRESSURE OFFSHORE CONTINUES TO DRIVE WEAK EASTERLY
FLOW THROUGH THE COLUMBIA GORGE AND INTO THE PORTLAND AREA. A WEAK
CLIPPER SYSTEM WILL PUSH DOWN FROM THE YUKON BRINGING A CHANCE OF
SNOW AND OR FREEZING DRIZZLE MAINLY FOR OUR NORTHERN ZONES INTO
TUESDAY. WEDNESDAY SHOULD REMAIN CHILLY AND DRY...THOUGH A LITTLE
WARMER THAN THE PAST COUPLE DAYS AS OUR AIR MASS SLOWLY MODERATES.
THE NEXT SYSTEM LOOKS STRONGER...AND MAY ENCOUNTER A STUBBORN LOW-
LEVEL COLD AIR MASS AS PRECIPITATION SPREADS ONSHORE. THIS MAY
RESULT IN MORE FROZEN OR FREEZING PRECIPITATION BEFORE A PACIFIC AIR
MASS FINALLY TAKES OVER LATE IN THE WEEK.
&&
.UPDATE...WEAK LOW JUST OFF THE COAST HAVE DEVELOP A BIT OF HYBRID
FREEZING RAIN AND DRIZZLE. A QUICK ANALYSIS OF MODEL SOUNDINGS AND
VERTICAL TEMPERATURE PROFILE ESTIMATED OBSERVATIONS SHOW THE UPPER
LAYER OF THE PRECIP GENERATION REGION (AROUND 850MB) IS SOMEWHERE
AROUND -5 TO -6 DEGREES C...NOT QUITE COLD ENOUGH TO PRODUCE ALL
SNOW AND STILL CLEARLY CAPABLE OF CREATING THE SUPERCOOLED WATER
DROPS. REPORT FROM LONG BEACH IS A LIGHT GLAZE BUT ENOUGH TO IMPACT
TRAVEL. HAVE ADDED A FREEZING DRIZZLE MENTION TO THE ADVISORY PLUS
ADDED THE NORTH OREGON COAST, THE WILLIPA HILLS, AND THE NORTH COAST
RANGE. PRESSURE GRADIENTS ARE STILL INDICATING OFFSHORE FLOW WHICH
WILL LIMIT TEMPERATURES RISES. HAVE DECIDED TO ALSO PULL ALL RAIN
MIX FROM THE FORECAST AS WINDS DO NOT APPEAR TO FAVOR SIGNIFICANT
WARMING. FAIRLY SOLID CLOUD COVER WILL ALSO INHIBIT WARMING.
SEEMS LIKE THIS INITIAL BAND WILL STILL ENCOUNTER DRIER INLAND AIR AS
IT CROSSES THE COAST RANGES LEAVING SOME LIGHT FLURRIES ACROSS THE
METRO AREA. LEFT THE ADVISORY ALONE FOR NOW COVERING THE METRO BUT
DO HAVE CONCERNS FOR A LIGHT FREEZING DRIZZLE TO OCCUR FOR THE
EVENING COMMUTE. LEAVING EARLY FROM WORK WOULD PROBABLY BE A GOOD
IDEA. DONT EXPECT A WIDESPREAD ICING EVENT THIS AFTERNOON/EVENING
BUT WOULD NOT BE SURPRISED TO SEE POCKETS OF LIGHT ICING UNDER
OCCASIONAL FREEZING DRIZZLE MIXED IN WITH THE SHOW SHOWERS.
AM STILL CONSIDERING WHAT TO MAKE OF THE OVERNIGHT CONDITIONS
TONIGHT. A QUICK ANALYSIS SHOWS ANY MIXED FREEZING DRIZZLE WILL
CONVERT BACK TO ALL SNOW AS THE MIDLEVELS COOL OVERNIGHT...EXCEPT
FOR POSSIBLY THE COAST. PRECIP TYPING COULD BECOME MORE COMPLICATED
OVERNIGHT AND EARLY DAYLIGHT TUESDAY FOR THE INLAND AREAS. WILL NEED
TO SPEND MORE TIME WITH ANALYSIS THOUGH. UPDATED ZONES AND GRIDS ARE
ON THEIR WAY. /JBONK
&&
.PREV DISC... /ISSUED 400 AM PST MON DEC 9 2013/
SHORT TERM...TONIGHT THROUGH WEDNESDAY... ONE LAST BITTERLY COLD
NIGHT OUT THERE TONIGHT BEFORE THE SLOW PROGRESSION OUT OF THE
COLD SNAP BEGINS. SEEING SOME OF THAT WITH THE COAST REMAINING
GENERALLY IN THE 20S. IT IS A BALMY 3 DEGREES IN EUGENE AND PLENTY
OF TEENS INLAND. TEMPS AND DEW POINTS ARE UP A LITTLE FROM LAST NIGHT
WHICH SHOULD PREVENT WIDESPREAD SINGLE DIGITS.
LOWER CLOUDS ARE ROLLING INTO THE COAST THIS MORNING...AND KLGX RADAR
DEPICTS SOME SHOWER ACTIVITY OFFSHORE THAT IS SOMEWHAT DYING OUT ON
THE LEADING EDGE. LATEST HI-RES GUIDANCE SUGGESTS THAT NOT A WHOLE
LOT OF INLAND PROGRESS THIS MORNING AS THE FLOW IS STILL MORE
NORTHERLY ALOFT...BUT LIKELY SOME LIGHT SNOW OR FLURRIES FOR THE S
WA/N OR COAST AND COAST RANGE.
A SOMEWHAT CHALLENGING FORECAST COMING UP THE NEXT FEW DAYS AFTER THE
NEAR TERM AS SEVERAL WEAK WAVES MOVE THROUGH BUT MIXED SIGNALS WITH
REGARDS TO PRECIPITATION. COULD SEE SOME VERY LIGHT SNOW/FLURRIES OR
SOME FREEZING DRIZZLE.AFTER THIS MORNING SEVERAL MODELS BRING LIGHT
PRECIPITATION (0.02" QPF OR LESS) INTO THE INTERIOR THIS AFTERNOON.
CURRENT KLGX DATA WOULD SUGGEST THAT PRECIPITATION WILL CONTINUE
WORKING INLAND...BUT MAY HAVE PROBLEMS WITH THE DRY AIR MASS.
MEANWHILE THE HRRR AND NAM KEEP PRECIPITATION CONFINED TO COAST AND
COAST RANGE WHERE TEMPERATURE PROFILES BEGIN TO WARM GIVEN THE WEAK
ONSHORE FLOW TO THE POINT WHERE PRECIP TYPE WOULD CHANGE TO RAIN OR
MAYBE RAIN-SNOW MIX. MEANWHILE INLAND THE PROFILE WILL REMAIN ALL
BELOW FREEZING. AFTER THAT THERE IS A MORE DISTINCT WAVE OFF THE
COAST OF NORTHERN B.C. THAT WILL DROP S.E. AND PROVIDE A BIT MORE
ORGANIZED LIFT TONIGHT INTO EARLY TUESDAY.
THE MOISTURE LAYER LOOKS TO BE RATHER SHALLOW. THESE SITUATIONS TEND
TO FAVOR FREEZING DRIZZLE...BUT ONLY IF YOU TAKE THEM FOR FACE VALUE
AND DO NOT CONSIDER THE INITIAL AIR MASS THAT THE CLOUD FORMED IN OR
THE ARMS THE SATURATED CLOUD IS MOVING INTO. SOUNDINGS SUGGEST THE
TOP OF THE MOIST LAYER AROUND -5 TO -7C. IT IS INCORRECT TO SUGGEST
THAT THERE WILL BE NO ICE CRYSTALS PRESENT IN THE CLOUD EVEN AT THESE
TEMPERATURES...JUST A QUESTION OF IF THERE ARE ENOUGH. CANNOT IGNORE
THE FACT THERE MAY ALSO BE SOME FREEZING DRIZZLE WHICH IF HITTING THE
COLD ROADS WOULD FREEZE LIKE THE SNOW DID THE OTHER DAY. THAT
SAID...AN INVESTIGATION OF DUAL-POLARIZATION DATA FROM KLGX AND
SIMPLY DUE TO THE FACT THAT REFLECTIVITY RETURNS ARE AS HIGH AS 30-40
DBZ SUGGEST THAT P-TYPE...AT LEAST CURRENTLY AND WITH THE FIRST BATCH
COMING IN IS SNOW AND NOT FREEZING DRIZZLE. THE 0Z QUILLAYUTE
SOUNDING DOES SUGGEST A WARM LAYER ABOVE THE MOIST LAYER..
BUT THE POTENTIAL OF FREEZING DRIZZLE CANNOT BE IGNORED AS THE LOWER
LEVEL PROFILE WARMS AND REDUCES ICE CRYSTAL AVAILABILITY ESPECIALLY
TOWARDS TUESDAY. AND ANY ACCUMULATING FREEZING DRIZZLE WOULD WARRANT
AN ADVISORY...ALSO DUE TO THE FACT DEW POINTS WILL BE MUCH HIGHER
MONDAY NIGHT INTO TUESDAY MORNING...ROADS HAVE THE POTENTIAL TO BE
QUITE HAZARDOUS...REGARDLESS OF THE PRECIP TYPE OR HOW MUCH/HOW
LITTLE SNOW ACTUALLY FALLS. SREF PLUMES KEEP ANYWHERE FROM LIGHT SNOW
ACCUMS TO UP TO AN INCH IN THE METRO. MODELS CONTINUE TO FAVOR THE
KELSO/CASTLE ROCK AREA AND THE I-5 CORRIDOR IN WASHINGTON FOR THE
MOST QPF. THEREFORE SEE NO REASON AT LEAST AT THIS TIME TO CHANGE THE
HEADLINE...BUT WILL FOCUS ON FREEZING DRIZZLE/SNOW POTENTIAL AND ROAD
IMPACTS. SINCE THE CENTRAL VALLEY DOES NOT LOOK TO SEE MUCH SNOW...I
CAN FORESEE A SITUATION WHERE IF FREEZING DRIZZLE DOMINATES AND THE
PRECIP GETS A BIT FARTHER SOUTH...THAT AN ADVISORY WOULD BE
WARRANTED...BUT CONFIDENCE IS LOW. DO STILL THINK THAT 1-2" ARE
POSSIBLE IF THE P-TYPE REMAINS SNOW MAINLY NORTH OF THE COLUMBIA
RIVER AND ALSO TOWARDS ST HELENS/SCAPPOOSE. I HOPE THIS DOES NOT
COME BACK TO HAUNT ME...BUT AM CONTEMPLATING TO REMOVING THE CENTRAL
WILLAMETTE VALLEY FROM THE WINTER WX ADVISORY...AS QPF IN THESE
AREAS DOES NOT SUPPORT AT THAT MUCH IN THE WAY OF SNOW. IF FREEZING
DRIZZLE IS THE MORE DOMINANT P-TYPE...THAN AN ADVISORY WOULD THEN BE
WARRANTED. WILL WORK UP THE WSW HERE WITH REFINED TIMING AND
FINAL DECISIONS SHORTLY AND SEND AN AMENDED AFD WITH THE HEADLINES.
THE MAIN JET ENERGY COMING OUT OF WESTERN CANADA SHOULD SHIFT FARTHER
EAST BY WEDNESDAY...ALLOWING SOME CLEARING AND POSSIBLY ANOTHER CLEAR
CALM AND CHILLY MORNING FOR SOME AREAS WED MORNING. EXPECT THERE TO
THEN BE FOG/FREEZING FOG. AFTER BURN OFF AND WITH SOME
SUNSHINE AND A SOMEWHAT MODERATED AIR MASS...MOST AREAS SHOULD BE
ABLE TO GET ABOVE FREEZING WEDNESDAY. HAVE DRIED OUT THE FORECAST
FOR WEDS AND WEDNESDAY NIGHT WITH THE EXPECTED TREND OF BACKING OFF
THE ARRIVAL OF THE PACIFIC SYSTEM WITH A COLD AND STRONG UPPER RIDGE
IN PLACE. /KMD
LEFT PREVIOUS DISCUSSION IN PLACE FOR THE LATTER PART OF THE SHORT
TERM FROM THE EVENING SHIFT AS MUCH OF THIS SHIFT WAS SPENT FINE
TUNING THE DETAILS THROUGH WEDNESDAY NIGHT.... NO DOUBT THIS IS AN
HISTORIC COLD AIR MASS. WHICH BRINGS US TO OUR NEXT FORECAST
CHALLENGE...THE PRECIPITATION TYPE EXPECTED FROM OUR NEXT EVENT.
CONSIDERING THE MAGNITUDE OF COLD ASSOCIATED WITH THIS AIR MASS...IT
IS VERY HARD TO BELIEVE WEAK CLIPPER SYSTEMS WILL BE SUFFICIENT TO
ERODE THE COLD AIR ENTRENCHED OVER THE PACIFIC NORTHWEST. WE CONTINUE
TO DISAGREE WITH MODEL GUIDANCE THAT SUGGESTS THE COLD AIR WILL SCOUR
OUT QUICKLY...AND OUR TEMPERATURE AND PRECIPITATION TYPE FORECAST
REFLECTS THAT ALL THE WAY INTO THURSDAY. WEAGLE
LONG TERM...NO CHANGES TO THE GRIDS OTHER THAN TO BACK OFF ON POPS A
BIT TO START THURSDAY SO REST OF THE DISCUSSION REMAINS
UNCHANGED...WILL LET THE DAY SHIFT REVISIT THE CHANGE IN TIMING AND
IMPACTS ON THERMAL PROFILES...WEDNESDAY NIGHT THROUGH
SUNDAY...OVERALL NO CHANGES TO THE THINKING BEHIND THE EXTENDED
FORECAST. DID SOME MANIPULATION OF THE GRIDS TO ATTEMPT TO BETTER
EXPRESS THE MIXED PRECIPITATION POTENTIAL WITH THE LATE WEEK SYSTEM.
WEAGLE
PREVIOUS DISCUSSION FOLLOWS...THE WELL ESTABLISHED COLD ARCTIC AIR
MASS WILL BEGIN TO MODERATE AS FLOW ALOFT BECOMES MORE WESTERLY.
TEMPERATURES LOOK TO TREND BACK TO SEASONAL NORMALS THROUGH THE
SECOND HALF OF NEXT WEEK. THE 12Z GFS AND ECMWF ARE A BIT SLOWER TO
BRING A SYSTEM ONSHORE EARLY THURSDAY SO HAVE ADJUSTED POP GRIDS TO
REFLECT THIS. FORECAST MODELS BRING THE HEAVIEST PRECIP ONSHORE
MIDDAY THURSDAY...WITH THE GFS SOLUTION ABOUT 6 HOURS FASTER. THERE
REMAINS SOME CONCERN THAT THE MODELS ARE TOO QUICK TO WARM THE AIR
MASS AFTER THIS PERIOD OF RECORD-SETTING COLD...SO IT IS POSSIBLE
THAT THIS PRECIPITATION MAY BEGIN IN THE FORM OF SNOW OR FREEZING
RAIN. THIS IS PARTICULARLY THE CASE FOR UPPER HOOD RIVER...THE
COLUMBIA RIVER GORGE..AND THE NORTHERN WILLAMETTE VALLEY. OTHERWISE
RAIN AND CASCADE SNOW IS EXPECTED TO CONTINUE THROUGH FRIDAY NIGHT.
THERE MAY BE A BRIEF DRY PERIOD AT LEAST PART OF THE DAY SATURDAY AS
LOW LEVEL FLOW WILL TURN SOUTHERLY BEFORE THE THE NEXT SYSTEM
ARRIVES SATURDAY AFTERNOON OR EVENING BRINGING RAIN ACROSS THE
FORECAST AREA.CULLEN
&&
.AVIATION...MAINLY VFR THROUGH 18Z...WITH POCKETS OF IFR IN FOG IN S
WILLAMETTE VALLEY. COAST WILL BE PREDOMINANTLY MVFR IN LIGHT
SNOW...WITH OCCASIONAL IFR IN SNOW POSSIBLE THROUGH EARLY TUESDAY.
FREEZING DRIZZLE IS ALSO POSSIBLE NEAR THE COAST. INLAND FROM KSLE
NORTH EXPECT MVFR IN OCCASIONAL LIGHT SNOW...PRIMARILY AFTER
18Z...WITH IFR IN SNOW POSSIBLE AFTER 03Z. SOUTH OF KSLE WILL BE VFR
THROUGH 00Z.
KPDX AND APPROACHES...VFR WITH LIGHT EAST WINDS. OCCASIONAL MVFR IN
FLURRIES OR LIGHT SNOW TODAY...ESPECIALLY AFTER 18Z. IFR IN SNOW
POSSIBLE LATE TONIGHT AFTER 03Z.
&&
.MARINE...NO UPDATES. PREVIOUS DISCUSSION FOLLOWS. BENIGN WEATHER
THROUGH WED. HIGH PRES OVER PAC NW MAINTAINS LIGHT OFFSHORE FLOW
THROUGH WED. WILL WILL TURN MORE W TO SW TUE AND WED AS HIGH WEAKENS
AND LOWER PRES APPROACHES FROM THE W. SEAS HOLDING AT 2 TO 4 FT
TODAY AND TUE...THEN BUILD SLIGHTLY LATER TUE AND WED.
STRONG COLD FRONT WILL ARRIVE ON THU...WITH S GALES EXPECTED. SEAS
WILL BUILD BACK CLOSER TO 10 FT.
&&
.PQR WATCHES/WARNINGS/ADVISORIES...
OR...WINTER WEATHER ADVISORY FROM 1 PM THIS AFTERNOON TO 1 PM PST
TUESDAY FOR LOWER COLUMBIA.
WINTER WEATHER ADVISORY UNTIL 10 PM PST THIS EVENING FOR COAST
RANGE OF NORTHWEST OREGON-NORTH OREGON COAST.
WINTER WEATHER ADVISORY FROM 4 PM THIS AFTERNOON TO 1 PM PST
TUESDAY FOR GREATER PORTLAND METRO AREA.
WA...WINTER WEATHER ADVISORY FROM 1 PM THIS AFTERNOON TO 1 PM PST
TUESDAY FOR I-5 CORRIDOR IN COWLITZ COUNTY.
WINTER WEATHER ADVISORY UNTIL 10 PM PST THIS EVENING FOR SOUTH
WASHINGTON COAST-WILLAPA HILLS.
WINTER WEATHER ADVISORY FROM 4 PM THIS AFTERNOON TO 1 PM PST
TUESDAY FOR GREATER VANCOUVER AREA.
PZ...NONE.
&&
$$
MORE WEATHER INFORMATION ONLINE AT..
HTTP://WEATHER.GOV/PORTLAND
INTERACT WITH US VIA SOCIAL MEDIA
WWW.FACEBOOK.COM/US.NATIONALWEATHERSERVICE.PORTLAND.GOV
WWW.TWITTER.COM/NWSPORTLAND
THIS DISCUSSION IS FOR NORTHWEST OREGON AND SOUTHWEST WASHINGTON FROM
THE CASCADE CREST TO 60 NAUTICAL MILES OFFSHORE. THE AREA IS COMMONLY
REFERRED TO AS THE FORECAST AREA.
AREA FORECAST DISCUSSION
NWS PORTLAND OR
400 AM PST MON DEC 9 2013
.SYNOPSIS...ANOTHER VERY COLD NIGHT AS ARCTIC HIGH PRESSURE REMAINS
DOMINANT OVER THE PACIFIC NORTHWEST. LOWER PRESSURE OFFSHORE
CONTINUES TO DRIVE WEAK EASTERLY FLOW THROUGH THE COLUMBIA GORGE AND
INTO THE PORTLAND AREA. A WEAK CLIPPER SYSTEM WILL PUSH DOWN FROM
THE YUKON LATER TODAY...BRINGING A CHANCE OF SNOW AND OR FREEZING
DRIZZLE MAINLY FOR OUR NORTHERN ZONES INTO TUESDAY. WEDNESDAY SHOULD
REMAIN CHILLY AND DRY...THOUGH A LITTLE WARMER THAN THE PAST COUPLE
DAYS AS OUR AIR MASS SLOWLY MODERATES. THE NEXT SYSTEM LOOKS
STRONGER...AND MAY ENCOUNTER A STUBBORN LOW-LEVEL COLD AIR MASS AS
PRECIPITATION SPREADS ONSHORE. THIS MAY RESULT IN MORE FROZEN OR
FREEZING PRECIPITATION BEFORE A PACIFIC AIR MASS FINALLY TAKES OVER
LATE IN THE WEEK.
&&
.UPDATE...UPDATED HEADLINES BELOW. CONFIDENCE WAS NOT HIGH ENOUGH TO
PUSH BACK THE ADVISORY FOR THE METRO AREA TO AFTER THE EVENING COMMUTE AS
GUIDANCE IS STILL MIXED...SO FOR NOW KEPT THE 4 PM START TIME.
.SHORT TERM...TONIGHT THROUGH WEDNESDAY...
ONE LAST BITTERLY COLD NIGHT OUT THERE TONIGHT BEFORE THE SLOW
PROGRESSION OUT OF THE COLDSNAP BEGINS. SEEING SOME OF THAT WITH THE
COAST REMAINING GENERAALLY IN THE 20S. IT IS A BALMY 3 DEGREES IN
EUGENE AND PLENTY OF TEENS INLAND. TEMPS AND DEWPOINTS ARE UP A
LITTLE FROM LAST NIGHT WHICH SHOULD PREVENT WIDESPREAD SINGLE
DIGITS.
LOWER CLOUDS ARE ROLLING INTO THE COAST THIS MORNING...AND KLGX RADAR
DEPICTS SOME SHOWER ACTIVITY OFFSHORE THAT IS SOMEWHAT DYING OUT ON
THE LEADING EDGE. LATEST HI-RES GUIDANCE SUGGESTS THAT NOT A WHOLE
LOT OF INLAND PROGRESS THIS MORNING AS THE FLOW IS STILL MORE
NORTHERLY ALOFT...BUT LIKELY SOME LIGHT SNOW OR FLURRIES FOR THE S
WA/N OR COAST AND COAST RANGE.
A SOMEWHAT CHALLENGING FORECAST COMING UP THE NEXT FEW DAYS AFTER THE
NEAR TERM AS SEVERAL WEAK WAVES MOVE THROUGH BUT MIXED SIGNALS WITH
REGARDS TO PRECIPITATION. COULD SEE SOME VERY LIGHT SNOW/FLURRIES OR
SOME FREEZING DRIZZLE.AFTER THIS MORNING SEVERAL MODELS BRING LIGHT
PRECIPITATION (0.02" QPF OR LESS) INTO THE INTERIOR THIS AFTERNOON.
CURRENT KLGX DATA WOULD SUGGEST THAT PRECIPITATION WILL CONTINUE
WORKING INLAND...BUT MAY HAVE PROBLEMS WITH THE DRY AIR MASS.
MEANWHILE THE HRRR AND NAM KEEP PRECIPITATION CONFINED TO COAST AND
COAST RANGE WHERE TEMPERATURE PROFILES BEGIN TO WARM GIVEN THE WEAK
ONSHORE FLOW TO THE POINT WHERE PRECIP TYPE WOULD CHANGE TO RAIN OR
MAYBE RAIN-SNOW MIX. MEANWHILE INLAND THE PROFILE WILL REMAIN ALL
BELOW FREEZING. AFTER THAT THERE IS A MORE DISTINCT WAVE OFF THE
COAST OF NORTHERN B.C. THAT WILL DROP S.E. AND PROVIDE A BIT MORE
ORGANIZED LIFT TONIGHT INTO EARLY TUESDAY.
THE MOISTURE LAYER LOOKS TO BE RATHER SHALLOW. THESE SITUATIONS TEND
TO FAVOR FREEZING DRIZZLE...BUT ONLY IF YOU TAKE THEM FOR FACE VALUE
AND DO NOT CONSIDER THE INITIAL AIRMASS THAT THE CLOUD FORMED IN OR
THE AIRMASS THE SATURATED CLOUD IS MOVING INTO. SOUNDINGS SUGGEST THE
TOP OF THE MOIST LAYER AROUND -5 TO -7C. IT IS INCORRECT TO SUGGEST
THAT THERE WILL BE NO ICE CRYSTALS PRESENT IN THE CLOUD EVEN AT THESE
TEMPERATURES...JUST A QUESTION OF IF THERE ARE ENOUGH. CANNOT IGNORE
THE FACT THERE MAY ALSO BE SOME FREEZING DRIZZLE WHICH IF HITTING THE
COLD ROADS WOULD FREEZE LIKE THE SNOW DID THE OTHER DAY. THAT
SAID...AN INVESTIGATION OF DUAL-POLARIZATION DATA FROM KLGX AND
SIMPLY DUE TO THE FACT THAT REFLECTIVITY RETURNS ARE AS HIGH AS 30-40
DBZ SUGGEST THAT P-TYPE...AT LEAST CURRENTLY AND WITH THE FIRST BATCH
COMING IN IS SNOW AND NOT FREEZING DRIZZLE. THE 0Z QUILLAYUTE
SOUNDING DOES SUGGEST A WARM LAYER ABOVE THE MOIST LAYER..
BUT THE POTENTIAL OF FREEZING DRIZZLE CANNOT BE IGNORED AS THE LOWER
LEVEL PROFILE WARMS AND REDUCES ICE CRYSTAL AVAILABILITY ESPECIALLY
TOWARDS TUESDAY. AND ANY ACCUMULATING FREEZING DRIZZLE WOULD WARRANT
AN ADVISORY...ALSO DUE TO THE FACT DEWPOINTS WILL BE MUCH HIGHER
MONDAY NIGHT INTO TUESDAY MORNING...ROADS HAVE THE POTENTIAL TO BE
QUITE HAZARDOUS...REGARDLESS OF THE PRECIP TYPE OR HOW MUCH/HOW
LITTLE SNOW ACTUALLY FALLS. SREF PLUMES KEEP ANYWHERE FROM LIGHT SNOW
ACCUMS TO UP TO AN INCH IN THE METRO. MODELS CONTINUE TO FAVOR THE
KELSO/CASTLE ROCK AREA AND THE I-5 CORRIDOR IN WASHINGTON FOR THE
MOST QPF. THEREFORE SEE NO REASON AT LEAST AT THIS TIME TO CHANGE THE
HEADLINE...BUT WILL FOCUS ON FREEZING DRIZZLE/SNOW POTENTIAL AND ROAD
IMPACTS. SINCE THE CENTRAL VALLEY DOES NOT LOOK TO SEE MUCH SNOW...I
CAN FORESEE A SITUATION WHERE IF FREEZING DRIZZLE DOMINATES AND THE
PRECIP GETS A BIT FARTHER SOUTH...THAT AN ADVISORY WOULD BE
WARRANTED...BUT CONFIDENCE IS LOW. DO STILL THINK THAT 1-2" ARE
POSSIBLE IF THE P-TYPE REMAINS SNOW MAINLY NORTH OF THE COLUMBIA
RIVER AND ALSO TOWARDS ST HELENS/SCAPPOOSE. I HOPE THIS DOES NOT
COME BACK TO HAUNT ME...BUT AM CONTEMPLATING TO REMOVING THE CENTRAL
WILLAMETTE VALLEY FROM THE WINTER WX ADVISORY...AS QPF IN THESE
AREAS DOES NOT SUPPORT AT THAT MUCH IN THE WAY OF SNOW. IF FREEZING
DRIZZLE IS THE MORE DOMINANT P-TYPE...THAN AN ADVISORY WOULD THEN BE
WARRANTED. WILL WORK UP THE WSW HERE WITH REFINED TIMING AND
FINAL DECISIONS SHORTLY AND SEND AN AMENDED AFD WITH THE HEADLINES.
THE MAIN JET ENERGY COMING OUT OF WESTERN CANADA SHOULD SHIFT FARTHER
EAST BY WEDNESDAY...ALLOWING SOME CLEARING AND POSSIBLY ANOTHER CLEAR
CALM AND CHILLY MORNING FOR SOME AREAS WED MORNING. EXPECT THERE TO
THEN BE FOG/FREEZING FOG. AFTER BURN OFF AND WITH SOME
SUNSHINE AND A SOMEWHAT MODERATED AIR MASS...MOST AREAS SHOULD BE
ABLE TO GET ABOVE FREEZING WEDNESDAY. HAVE DRIED OUT THE FORECAST
FOR WEDS AND WEDNESDAY NIGHT WITH THE EXPECTED TREND OF BACKING OFF
THE ARRIVAL OF THE PACIFIC SYSTEM WITH A COLD AND STRONG UPPER RIDGE
IN PLACE. /KMD
LEFT PREVIOUS DISCUSSION IN PLACE FOR THE LATTER PART OF THE SHORT
TERM FROM THE EVENING SHIFT AS MUCH OF THIS SHIFT WAS SPENT FINE
TUNING THE DETAILS THROUGH WEDNESDAY NIGHT.... NO DOUBT THIS IS AN
HISTORIC COLD AIR MASS. WHICH BRINGS US TO OUR NEXT FORECAST
CHALLENGE...THE PRECIPITATION TYPE EXPECTED FROM OUR NEXT EVENT.
CONSIDERING THE MAGNITUDE OF COLD ASSOCIATED WITH THIS AIR MASS...IT
IS VERY HARD TO BELIEVE WEAK CLIPPER SYSTEMS WILL BE SUFFICIENT TO
ERODE THE COLD AIR ENTRENCHED OVER THE PACIFIC NORTHWEST. WE CONTINUE
TO DISAGREE WITH MODEL GUIDANCE THAT SUGGESTS THE COLD AIR WILL SCOUR
OUT QUICKLY...AND OUR TEMPERATURE AND PRECIPITATION TYPE FORECAST
REFLECTS THAT ALL THE WAY INTO THURSDAY. WEAGLE
.LONG TERM...NO CHANGES TO THE GRIDS OTHER THAN TO BACK OFF ON
POPS A BIT TO START THURSDAY SO REST OF THE DISCUSSION REMAINS
UNCHANGED...WILL LET THE DAY SHIFT REVISIT THE CHANGE IN TIMING AND
IMPACTS ON THERMAL PROFILES...WEDNESDAY NIGHT THROUGH
SUNDAY...OVERALL NO CHANGES TO THE THINKING BEHIND THE EXTENDED
FORECAST. DID SOME MANIPULATION OF THE GRIDS TO ATTEMPT TO BETTER
EXPRESS THE MIXED PRECIPITATION POTENTIAL WITH THE LATE WEEK SYSTEM.
WEAGLE
PREVIOUS DISCUSSION FOLLOWS...THE WELL ESTABLISHED COLD ARCTIC AIR
MASS WILL BEGIN TO MODERATE AS FLOW ALOFT BECOMES MORE WESTERLY.
TEMPERATURES LOOK TO TREND BACK TO SEASONAL NORMALS THROUGH THE
SECOND HALF OF NEXT WEEK. THE 12Z GFS AND ECMWF ARE A BIT SLOWER TO
BRING A SYSTEM ONSHORE EARLY THURSDAY SO HAVE ADJUSTED POP GRIDS TO
REFLECT THIS. FORECAST MODELS BRING THE HEAVIEST PRECIP ONSHORE
MIDDAY THURSDAY...WITH THE GFS SOLUTION ABOUT 6 HOURS FASTER. THERE
REMAINS SOME CONCERN THAT THE MODELS ARE TOO QUICK TO WARM THE AIR
MASS AFTER THIS PERIOD OF RECORD-SETTING COLD...SO IT IS POSSIBLE
THAT THIS PRECIPITATION MAY BEGIN IN THE FORM OF SNOW OR FREEZING
RAIN. THIS IS PARTICULARLY THE CASE FOR UPPER HOOD RIVER...THE
COLUMBIA RIVER GORGE..AND THE NORTHERN WILLAMETTE VALLEY. OTHERWISE
RAIN AND CASCADE SNOW IS EXPECTED TO CONTINUE THROUGH FRIDAY NIGHT.
THERE MAY BE A BRIEF DRY PERIOD AT LEAST PART OF THE DAY SATURDAY AS
LOW LEVEL FLOW WILL TURN SOUTHERLY BEFORE THE THE NEXT SYSTEM
ARRIVES SATURDAY AFTERNOON OR EVENING BRINGING RAIN ACROSS THE
FORECAST AREA.CULLEN
&&
.AVIATION...VFR CONDITIONS THIS AM...WITH POCKETS OF FOG IN S
WILLAMETTE VALLEY. CLOUDS INCREASING ALONG OREGON COAST...AND
SHOULD PERSIST THROUGH TUE AM. FLURRIES ON THE COAST THIS AM.
CIGS ON S WASH/N ORE COAST WILL LOWER TO MVFR AFTER 16Z...WITH
OCCASIONAL MVFR VIS WITH BURSTS OF SNOW. NOT MUCH CHANGE ON COAST
FOR TONIGHT...BUT INLAND CIGS WILL DROP TO LOW VFR OR MVFR WITH
MVFR VIS IN OCCASIONAL LIGHT SNOW ACROSS N TAF SITES.
KPDX AND APPROACHES...VFR WITH LIGHT EAST WINDS CONTINUE. WILL
HAVE INCREASING LOW VFR CLOUDS THIS AM...WITH SOME OCCASIONAL
FLURRIES FROM 20Z THROUGH 06Z TUE. CIGS WILL LOWER TO MVFR AFTER
03Z...WITH INCREASING THREAT OF SNOW LATE OVERNIGHT INTO TUE AM.
ROCKEY.
.MARINE...BENIGN WEATHER THROUGH WED. HIGH PRES OVER PAC NW
MAINTAINS LIGHT OFFSHORE FLOW THROUGH WED. WILL WILL TURN MORE W
TO SW TUE AND WED AS HIGH WEAKENS AND LOWER PRES APPROACHES FROM
THE W. SEAS HOLDING AT 2 TO 4 FT TODAY AND TUE...THEN BUILD
SLIGHTLY LATER TUE AND WED.
STRONG COLD FRONT WILL ARRIVE ON THU...WITH S GALES EXPECTED.
SEAS WILL BUILD BACK CLOSER TO 10 FT.
&&
.PQR WATCHES/WARNINGS/ADVISORIES...
OR...WEATHER WEATHER ADVISORY...
1 PM TODAY TO 1 PM TUE FOR LOWER COLUMBIA.
4 PM TODAY TO 1 PM TUE FOR NORTH WILLAMETTE VALLEY
INCLUDING THE GREATER PORTLAND METRO AREA.
WA...WINTER WEATHER ADVISORY...
7 AM TO 10 PM TODAY FOR SOUTH WASHINGTON COAST.
1 PM TODAY TO 1 PM TUE FOR I-5 CORRIDOR IN COWLITZ CTY.
4 PM TODAY TO 1 PM TUE FOR GREATER VANCOUVER AREA
PZ...NONE.
&&
$$
MORE WEATHER INFORMATION ONLINE AT..
HTTP://WEATHER.GOV/PORTLAND
INTERACT WITH US VIA SOCIAL MEDIA
WWW.FACEBOOK.COM/US.NATIONALWEATHERSERVICE.PORTLAND.GOV
WWW.TWITTER.COM/NWSPORTLAND
THIS DISCUSSION IS FOR NORTHWEST OREGON AND SOUTHWEST WASHINGTON FROM
THE CASCADE CREST TO 60 NAUTICAL MILES OFFSHORE. THE AREA IS COMMONLY
REFERRED TO AS THE FORECAST AREA.
AREA FORECAST DISCUSSION
NWS PORTLAND OR
320 AM PST MON DEC 9 2013
.SYNOPSIS...ANOTHER VERY COLD NIGHT AS ARCTIC HIGH PRESSURE REMAINS
DOMINANT OVER THE PACIFIC NORTHWEST. LOWER PRESSURE OFFSHORE
CONTINUES TO DRIVE WEAK EASTERLY FLOW THROUGH THE COLUMBIA GORGE AND
INTO THE PORTLAND AREA. A WEAK CLIPPER SYSTEM WILL PUSH DOWN FROM
THE YUKON LATER TODAY...BRINGING A CHANCE OF SNOW AND OR FREEZING
DRIZZLE MAINLY FOR OUR NORTHERN ZONES INTO TUESDAY. WEDNESDAY SHOULD
REMAIN CHILLY AND DRY...THOUGH A LITTLE WARMER THAN THE PAST COUPLE
DAYS AS OUR AIR MASS SLOWLY MODERATES. THE NEXT SYSTEM LOOKS
STRONGER...AND MAY ENCOUNTER A STUBBORN LOW-LEVEL COLD AIR MASS AS
PRECIPITATION SPREADS ONSHORE. THIS MAY RESULT IN MORE FROZEN OR
FREEZING PRECIPITATION BEFORE A PACIFIC AIR MASS FINALLY TAKES OVER
LATE IN THE WEEK.
&&
.SHORT TERM...TONIGHT THROUGH WEDNESDAY...
ONE LAST BITTERLY COLD NIGHT OUT THERE TONIGHT BEFORE THE SLOW
PROGRESSION OUT OF THE COLDSNAP BEGINS. SEEING SOME OF THAT WITH THE
COAST REMAINING GENERAALLY IN THE 20S. IT IS A BALMY 3 DEGREES IN
EUGENE AND PLENTY OF TEENS INLAND. TEMPS AND DEWPOINTS ARE UP A
LITTLE FROM LAST NIGHT WHICH SHOULD PREVENT WIDESPREAD SINGLE
DIGITS.
LOWER CLOUDS ARE ROLLING INTO THE COAST THIS MORNING...AND KLGX RADAR
DEPICTS SOME SHOWER ACTIVITY OFFSHORE THAT IS SOMEWHAT DYING OUT ON
THE LEADING EDGE. LATEST HI-RES GUIDANCE SUGGESTS THAT NOT A WHOLE
LOT OF INLAND PROGRESS THIS MORNING AS THE FLOW IS STILL MORE
NORTHERLY ALOFT...BUT LIKELY SOME LIGHT SNOW OR FLURRIES FOR THE S
WA/N OR COAST AND COAST RANGE.
A SOMEWHAT CHALLENGING FORECAST COMING UP THE NEXT FEW DAYS AFTER THE
NEAR TERM AS SEVERAL WEAK WAVES MOVE THROUGH BUT MIXED SIGNALS WITH
REGARDS TO PRECIPITATION. COULD SEE SOME VERY LIGHT SNOW/FLURRIES OR
SOME FREEZING DRIZZLE.AFTER THIS MORNING SEVERAL MODELS BRING LIGHT
PRECIPITATION (0.02" QPF OR LESS) INTO THE INTERIOR THIS AFTERNOON.
CURRENT KLGX DATA WOULD SUGGEST THAT PRECIPITATION WILL CONTINUE
WORKING INLAND...BUT MAY HAVE PROBLEMS WITH THE DRY AIR MASS.
MEANWHILE THE HRRR AND NAM KEEP PRECIPITATION CONFINED TO COAST AND
COAST RANGE WHERE TEMPERATURE PROFILES BEGIN TO WARM GIVEN THE WEAK
ONSHORE FLOW TO THE POINT WHERE PRECIP TYPE WOULD CHANGE TO RAIN OR
MAYBE RAIN-SNOW MIX. MEANWHILE INLAND THE PROFILE WILL REMAIN ALL
BELOW FREEZING. AFTER THAT THERE IS A MORE DISTINCT WAVE OFF THE
COAST OF NORTHERN B.C. THAT WILL DROP S.E. AND PROVIDE A BIT MORE
ORGANIZED LIFT TONIGHT INTO EARLY TUESDAY.
THE MOISTURE LAYER LOOKS TO BE RATHER SHALLOW. THESE SITUATIONS TEND
TO FAVOR FREEZING DRIZZLE...BUT ONLY IF YOU TAKE THEM FOR FACE VALUE
AND DO NOT CONSIDER THE INITIAL AIRMASS THAT THE CLOUD FORMED IN OR
THE AIRMASS THE SATURATED CLOUD IS MOVING INTO. SOUNDINGS SUGGEST THE
TOP OF THE MOIST LAYER AROUND -5 TO -7C. IT IS INCORRECT TO SUGGEST
THAT THERE WILL BE NO ICE CRYSTALS PRESENT IN THE CLOUD EVEN AT THESE
TEMPERATURES...JUST A QUESTION OF IF THERE ARE ENOUGH. CANNOT IGNORE
THE FACT THERE MAY ALSO BE SOME FREEZING DRIZZLE WHICH IF HITTING THE
COLD ROADS WOULD FREEZE LIKE THE SNOW DID THE OTHER DAY. THAT
SAID...AN INVESTIGATION OF DUAL-POLARIZATION DATA FROM KLGX AND
SIMPLY DUE TO THE FACT THAT REFLECTIVITY RETURNS ARE AS HIGH AS 30-40
DBZ SUGGEST THAT P-TYPE...AT LEAST CURRENTLY AND WITH THE FIRST BATCH
COMING IN IS SNOW AND NOT FREEZING DRIZZLE. THE 0Z QUILLAYUTE
SOUNDING DOES SUGGEST A WARM LAYER ABOVE THE MOIST LAYER..
BUT THE POTENTIAL OF FREEZING DRIZZLE CANNOT BE IGNORED AS THE LOWER
LEVEL PROFILE WARMS AND REDUCES ICE CRYSTAL AVAILABILITY ESPECIALLY
TOWARDS TUESDAY. AND ANY ACCUMULATING FREEZING DRIZZLE WOULD WARRANT
AN ADVISORY...ALSO DUE TO THE FACT DEWPOINTS WILL BE MUCH HIGHER
MONDAY NIGHT INTO TUESDAY MORNING...ROADS HAVE THE POTENTIAL TO BE
QUITE HAZARDOUS...REGARDLESS OF THE PRECIP TYPE OR HOW MUCH/HOW
LITTLE SNOW ACTUALLY FALLS. SREF PLUMES KEEP ANYWHERE FROM LIGHT SNOW
ACCUMS TO UP TO AN INCH IN THE METRO. MODELS CONTINUE TO FAVOR THE
KELSO/CASTLE ROCK AREA AND THE I-5 CORRIDOR IN WASHINGTON FOR THE
MOST QPF. THEREFORE SEE NO REASON AT LEAST AT THIS TIME TO CHANGE THE
HEADLINE...BUT WILL FOCUS ON FREEZING DRIZZLE/SNOW POTENTIAL AND ROAD
IMPACTS. SINCE THE CENTRAL VALLEY DOES NOT LOOK TO SEE MUCH SNOW...I
CAN FORESEE A SITUATION WHERE IF FREEZING DRIZZLE DOMINATES AND THE
PRECIP GETS A BIT FARTHER SOUTH...THAT AN ADVISORY WOULD BE
WARRANTED...BUT CONFIDENCE IS LOW. DO STILL THINK THAT 1-2" ARE
POSSIBLE IF THE P-TYPE REMAINS SNOW MAINLY NORTH OF THE COLUMBIA
RIVER AND ALSO TOWARDS ST HELENS/SCAPPOOSE. I HOPE THIS DOES NOT
COME BACK TO HAUNT ME...BUT AM CONTEMPLATING TO REMOVING THE CENTRAL
WILLAMETTE VALLEY FROM THE WINTER WX ADVISORY...AS QPF IN THESE
AREAS DOES NOT SUPPORT AT THAT MUCH IN THE WAY OF SNOW. IF FREEZING
DRIZZLE IS THE MORE DOMINANT P-TYPE...THAN AN ADVISORY WOULD THEN BE
WARRANTED. WILL WORK UP THE WSW HERE WITH REFINED TIMING AND
FINAL DECISIONS SHORTLY AND SEND AN AMENDED AFD WITH THE HEADLINES.
THE MAIN JET ENERGY COMING OUT OF WESTERN CANADA SHOULD SHIFT FARTHER
EAST BY WEDNESDAY...ALLOWING SOME CLEARING AND POSSIBLY ANOTHER CLEAR
CALM AND CHILLY MORNING FOR SOME AREAS WED MORNING. EXPECT THERE TO
THEN BE FOG/FREEZING FOG. AFTER BURN OFF AND WITH SOME
SUNSHINE AND A SOMEWHAT MODERATED AIR MASS...MOST AREAS SHOULD BE
ABLE TO GET ABOVE FREEZING WEDNESDAY. HAVE DRIED OUT THE FORECAST
FOR WEDS AND WEDNESDAY NIGHT WITH THE EXPECTED TREND OF BACKING OFF
THE ARRIVAL OF THE PACIFIC SYSTEM WITH A COLD AND STRONG UPPER RIDGE
IN PLACE. /KMD
LEFT PREVIOUS DISCUSSION IN PLACE FOR THE LATTER PART OF THE SHORT
TERM FROM THE EVENING SHIFT AS MUCH OF THIS SHIFT WAS SPENT FINE
TUNING THE DETAILS THROUGH WEDNESDAY NIGHT.... NO DOUBT THIS IS AN
HISTORIC COLD AIR MASS. WHICH BRINGS US TO OUR NEXT FORECAST
CHALLENGE...THE PRECIPITATION TYPE EXPECTED FROM OUR NEXT EVENT.
CONSIDERING THE MAGNITUDE OF COLD ASSOCIATED WITH THIS AIR MASS...IT
IS VERY HARD TO BELIEVE WEAK CLIPPER SYSTEMS WILL BE SUFFICIENT TO
ERODE THE COLD AIR ENTRENCHED OVER THE PACIFIC NORTHWEST. WE CONTINUE
TO DISAGREE WITH MODEL GUIDANCE THAT SUGGESTS THE COLD AIR WILL SCOUR
OUT QUICKLY...AND OUR TEMPERATURE AND PRECIPITATION TYPE FORECAST
REFLECTS THAT ALL THE WAY INTO THURSDAY. WEAGLE
.LONG TERM...NO CHANGES TO THE GRIDS OTHER THAN TO BACK OFF ON
POPS A BIT TO START THURSDAY SO REST OF THE DISCUSSION REMAINS
UNCHANGED...WILL LET THE DAY SHIFT REVISIT THE CHANGE IN TIMING AND
IMPACTS ON THERMAL PROFILES...WEDNESDAY NIGHT THROUGH
SUNDAY...OVERALL NO CHANGES TO THE THINKING BEHIND THE EXTENDED
FORECAST. DID SOME MANIPULATION OF THE GRIDS TO ATTEMPT TO BETTER
EXPRESS THE MIXED PRECIPITATION POTENTIAL WITH THE LATE WEEK SYSTEM.
WEAGLE
PREVIOUS DISCUSSION FOLLOWS...THE WELL ESTABLISHED COLD ARCTIC AIR
MASS WILL BEGIN TO MODERATE AS FLOW ALOFT BECOMES MORE WESTERLY.
TEMPERATURES LOOK TO TREND BACK TO SEASONAL NORMALS THROUGH THE
SECOND HALF OF NEXT WEEK. THE 12Z GFS AND ECMWF ARE A BIT SLOWER TO
BRING A SYSTEM ONSHORE EARLY THURSDAY SO HAVE ADJUSTED POP GRIDS TO
REFLECT THIS. FORECAST MODELS BRING THE HEAVIEST PRECIP ONSHORE
MIDDAY THURSDAY...WITH THE GFS SOLUTION ABOUT 6 HOURS FASTER. THERE
REMAINS SOME CONCERN THAT THE MODELS ARE TOO QUICK TO WARM THE AIR
MASS AFTER THIS PERIOD OF RECORD-SETTING COLD...SO IT IS POSSIBLE
THAT THIS PRECIPITATION MAY BEGIN IN THE FORM OF SNOW OR FREEZING
RAIN. THIS IS PARTICULARLY THE CASE FOR UPPER HOOD RIVER...THE
COLUMBIA RIVER GORGE..AND THE NORTHERN WILLAMETTE VALLEY. OTHERWISE
RAIN AND CASCADE SNOW IS EXPECTED TO CONTINUE THROUGH FRIDAY NIGHT.
THERE MAY BE A BRIEF DRY PERIOD AT LEAST PART OF THE DAY SATURDAY AS
LOW LEVEL FLOW WILL TURN SOUTHERLY BEFORE THE THE NEXT SYSTEM
ARRIVES SATURDAY AFTERNOON OR EVENING BRINGING RAIN ACROSS THE
FORECAST AREA.CULLEN
&&
.AVIATION...VFR CONDITIONS THIS AM...WITH POCKETS OF FOG IN S
WILLAMETTE VALLEY. CLOUDS INCREASING ALONG OREGON COAST...AND
SHOULD PERSIST THROUGH TUE AM. FLURRIES ON THE COAST THIS AM.
CIGS ON S WASH/N ORE COAST WILL LOWER TO MVFR AFTER 16Z...WITH
OCCASIONAL MVFR VIS WITH BURSTS OF SNOW. NOT MUCH CHANGE ON COAST
FOR TONIGHT...BUT INLAND CIGS WILL DROP TO LOW VFR OR MVFR WITH
MVFR VIS IN OCCASIONAL LIGHT SNOW ACROSS N TAF SITES.
KPDX AND APPROACHES...VFR WITH LIGHT EAST WINDS CONTINUE. WILL
HAVE INCREASING LOW VFR CLOUDS THIS AM...WITH SOME OCCASIONAL
FLURRIES FROM 20Z THROUGH 06Z TUE. CIGS WILL LOWER TO MVFR AFTER
03Z...WITH INCREASING THREAT OF SNOW LATE OVERNIGHT INTO TUE AM.
ROCKEY.
.MARINE...BENIGN WEATHER THROUGH WED. HIGH PRES OVER PAC NW
MAINTAINS LIGHT OFFSHORE FLOW THROUGH WED. WILL WILL TURN MORE W
TO SW TUE AND WED AS HIGH WEAKENS AND LOWER PRES APPROACHES FROM
THE W. SEAS HOLDING AT 2 TO 4 FT TODAY AND TUE...THEN BUILD
SLIGHTLY LATER TUE AND WED.
STRONG COLD FRONT WILL ARRIVE ON THU...WITH S GALES EXPECTED.
SEAS WILL BUILD BACK CLOSER TO 10 FT.
&&
.PQR WATCHES/WARNINGS/ADVISORIES...
OR...WEATHER WEATHER ADVISORY...
10 AM TODAY TO 10 AM TUE FOR LOWER COLUMBIA.
4 PM TODAY TO 4 PM TUE FOR NORTH WILLAMETTE VALLEY
INCLUDING THE GREATER PORTLAND METRO AREA.
4 PM TODAY TO 4 PM TUE FOR CENTRAL WILLAMETTE VALLEY.
WA...WINTER WEATHER ADVISORY...
7 AM TO 10 PM TODAY FOR SOUTH WASHINGTON COAST.
10 AM TODAY TO 10 AM TUE FOR I-5 CORRIDOR IN COWLITZ CTY.
4 PM TODAY TO 4 PM TUE FOR GREATER VANCOUVER AREA
PZ...NONE.
&&
$$
MORE WEATHER INFORMATION ONLINE AT..
HTTP://WEATHER.GOV/PORTLAND
INTERACT WITH US VIA SOCIAL MEDIA
WWW.FACEBOOK.COM/US.NATIONALWEATHERSERVICE.PORTLAND.GOV
WWW.TWITTER.COM/NWSPORTLAND
THIS DISCUSSION IS FOR NORTHWEST OREGON AND SOUTHWEST WASHINGTON FROM
THE CASCADE CREST TO 60 NAUTICAL MILES OFFSHORE. THE AREA IS COMMONLY
REFERRED TO AS THE FORECAST AREA.
AREA FORECAST DISCUSSION
NWS MEMPHIS TN
1124 AM CST MON DEC 9 2013
.UPDATE...
UPDATED FOR 18Z AVIATION DISCUSSION.
&&
.PREV DISCUSSION... /ISSUED 1027 AM CST MON DEC 9 2013/
DISCUSSION...
ANOTHER COLD DAY ON TAP ACROSS THE MIDSOUTH. CLOUDS ARE HANGING
TOUGH AND LATEST RAP SOUNDINGS INDICATE THAT THEY WILL REMAIN FOR
THE REST OF THE DAY. THE LACK OF SUN WILL MAKE IT TOUGH FOR TEMPS
TO CLIMB MUCH SO KNOCKED A COUPLE OF DEGREES OFF SOUTH OF I-40.
UPDATE OUT.
SJM
&&
.PREV DISCUSSION... /ISSUED 442 AM CST MON DEC 9 2013/
WEATHER CONDITIONS WERE CLOUDY AND COLD ACROSS THE MIDSOUTH EARLY
THIS MORNING. PRECIPITATION HAD MOVED OUT OF THE AREA AND ONLY
LIGHT FOG WAS BEING REPORTED IN A FEW SPOTS. THUS A MUCH QUIETER
NIGHT WEATHERWISE THAN LAST NIGHT.
MODELS ARE IN FAIRLY GOOD AGREEMENT THROUGH THE UPCOMING WEEK. THE
BIGGEST DISAGREEMENT IS THAT THE NAM SHOWS A LITTLE MORE
PRECIPITATION AND IS FURTHER NORTH WITH THE PRECIPITATION TONIGHT
THAN THE GFS AND ECMWF. VERY COLD WEATHER WILL CONTINUE THROUGH MUCH
OF THE WORK WEEK WITH ONE MORE THREAT OF FREEZING RAIN AND SLEET
TONIGHT.
FOR TODAY...CLOUDS ARE EXPECTED TO GRADUALLY BREAK UP THIS MORNING
LEAVING PARTIAL SUNSHINE ACROSS THE AREA BY THIS AFTERNOON. ANOTHER
PUSH OF MODIFIED POLAR AIR WILL MOVE INTO THE MIDSOUTH KEEPING IT
VERY COLD ACROSS MOST OF THE REGION. LEFT IN A SLIGHT CHANCE OF RAIN
IN ADVANCE OF THE NEXT SYSTEM ACROSS EXTREME SOUTHERN PORTIONS OF
NORTH MS THIS AFTERNOON...OTHERWISE IT WILL BE A DRY DAY ACROSS THE
MIDSOUTH.
FOR TONIGHT...WEAK SURFACE LOW PRESSURE WILL TRACK TO THE SOUTHEAST
OF THE MIDSOUTH. THIS PLACES THE MIDSOUTH ON THE NORTHWESTERN FRINGE
OF MOST OF THE PRECIPITATION WITH THE HIGHEST POPS AND AMOUNTS
FORECAST THROUGH NORTH MS. GENERALLY TOOK A COMPROMISE BETWEEN THE
VARIOUS MODELS. COLDER AIR WILL CONTINUE TO ADVECT INTO THE AREA
FROM THE NORTHWEST. AS A RESULT...PRECIPITATION WILL BE CHANGING TO
FREEZING RAIN AND SLEET FROM THE NORTHWEST. THERE IS A SLIGHT CHANCE
OF LIGHT SNOW NORTH OF INTERSTATE 40 MAINLY DUE TO AN UPPER LEVEL
TROUGH APPROACHING FROM THE WEST...LITTLE IF ANY ACCUMULATION OF
SNOW IS EXPECTED. ATTM...THINK THE BEST CHANCE FOR ANY ICE
ACCUMULATION FROM FREEZING RAIN AND SLEET WILL BE ALONG AND SOUTH OF
INTERSTATE 40 ACROSS PORTIONS OF WEST TENNESSEE...EAST CENTRAL
ARKANSAS AND NORTH MISSISSIPPI. A WINTER WEATHER ADVISORY MAY NEED
TO BE ISSUED FOR PORTIONS OF THIS AREA LATER TODAY...CONFIDENCE IS
NOT HIGH ENOUGH TO ISSUE AT THIS TIME. ANY ICE ACCUMULATIONS ARE
FORECAST TO BE LIGHT AND LESS THAN 1/10 OF AN INCH. PRECIPITATION
ACROSS MUCH OF NORTH MISSISSIPPI WILL BEGIN AS RAIN MIXED WITH
FREEZING RAIN IN SOME LOCATIONS...GRADUALLY BECOMING FREEZING RAIN
AND SLEET AS COLDER AIR PUSHES IN FROM THE NORTHWEST. ONLY MINOR
IF ANY ACCUMULATIONS OF SLEET ARE EXPECTED.
THE PRECIPITATION WILL MOVE EAST OF THE MIDSOUTH EARLY TUESDAY WITH
STRONG COLD HIGH PRESSURE SETTLING OVER THE MIDSOUTH. THE GOOD NEWS
IS THAT NO MORE PRECIPITATION IS FORECAST UNTIL FRIDAY. QUITE COLD
CONDITIONS ARE FORECAST WEDNESDAY MORNING UNDER MOSTLY CLEAR SKIES
WITH LOWS IN THE TEENS ACROSS A LARGE SECTION OF THE AREA. THE HIGH
PRESSURE SYSTEM WILL MOVE TO THE EAST DURING THE DAY WEDNESDAY WITH
SLIGHTLY LESS COLD TEMPERATURES...BUT DID NOT GO AS WARM AS THE MEX
GUIDANCE INDICATES. ANOTHER SURGE OF MODIFIED ARCTIC AIR WILL PUSH
INTO THE REGION WEDNESDAY NIGHT WITH THURSDAY MORNING FORECAST TO BE
THE COLDEST OF THE WEEK. LOW TEMPERATURES WILL DROP INTO THE TEENS
ACROSS MUCH OF THE AREA WITH LOWER TEENS FOR SOME AREAS. WILL NEED
TO MONITOR WIND CHILL READINGS AS THEY MAY DROP TO NEAR ZERO ACROSS
PORTIONS OF NORTHWEST TN.
A LARGE SCALE UPPER LEVEL TROUGH WILL APPROACH THE MIDSOUTH FROM THE
WEST FRIDAY BRINGING OUR NEXT CHANCE OF PRECIPITATION. AT THIS
TIME...INDICATIONS ARE THAT MOST IF NOT ALL OF THE PRECIPITATION
WILL BE RAIN BUT WILL NEED TO KEEP AN EYE ON THIS IN CASE IT DOES
NOT WARM UP AS QUICKLY AS EXPECTED...ESPECIALLY ACROSS NORTHERN
AREAS. THE UPPER LEVEL TROUGH WILL MOVE ACROSS THE REGION FRIDAY
NIGHT AND EARLY SATURDAY WITH WIDESPREAD RAIN. POPS WILL NEED TO BE
INCREASED IN LATER FORECASTS IF THESE MODEL TRENDS PERSIST. DRY AND
COOLER WEATHER IS FORECAST SUNDAY NIGHT AND MONDAY AS THE TROUGH
MOVES OFF TO THE EAST.
JCL
&&
.AVIATION...
18Z TAF CYCLE
CONFIDENCE INCREASING IN RESPECT TO A BRIEF WINTER WEATHER EVENT
MOVING UP FROM THE SOUTHWEST TONIGHT...AFFECTING MEM...TUP...AND
MKL. A LIGHT SNOW AND SLEET MIX WILL OCCASIONALLY FALL AT MEM AND
MKL STARTING THIS EVENING...AND AT THE SAME TIME PRECIPITATION
WILL START OUT AS A COLD RAIN AT TUP. THEN SOMETIME AFTER MIDNIGHT
FEEL PRECIPITATION WILL START TAPERING OFF WITH THE POSSIBILITY OF
PATCHY FREEZING DRIZZLE FORMING. CIGS WILL BE MAINLY MVFR...WITH
OCCASIONAL IFR CONDITIONS AT TUP. JBR MAY SEE OCCASIONAL VFR
CONDITIONS NEAR SUNSET. WINDS WILL BE NORTHERLY AT 8-12 KTS
BACKING NORTHWESTERLY LATE.
JAB
&&
.PRELIMINARY POINT TEMPS/POPS...
MEM 36 24 36 23 / 10 40 10 10
MKL 36 22 35 18 / 10 40 10 10
JBR 32 20 31 19 / 10 20 10 10
TUP 40 29 40 23 / 10 80 10 10
&&
.MEG WATCHES/WARNINGS/ADVISORIES...
AR...NONE.
MO...NONE.
MS...NONE.
TN...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS MEMPHIS TN
1027 AM CST MON DEC 9 2013
.DISCUSSION...
ANOTHER COLD DAY ON TAP ACROSS THE MIDSOUTH. CLOUDS ARE HANGING
TOUGH AND LATEST RAP SOUNDINGS INDICATE THAT THEY WILL REMAIN FOR
THE REST OF THE DAY. THE LACK OF SUN WILL MAKE IT TOUGH FOR TEMPS
TO CLIMB MUCH SO KNOCKED A COUPLE OF DEGREES OFF SOUTH OF I-40.
UPDATE OUT.
SJM
&&
PREV DISCUSSION... /ISSUED 442 AM CST MON DEC 9 2013/
WEATHER CONDITIONS WERE CLOUDY AND COLD ACROSS THE MIDSOUTH EARLY
THIS MORNING. PRECIPITATION HAD MOVED OUT OF THE AREA AND ONLY
LIGHT FOG WAS BEING REPORTED IN A FEW SPOTS. THUS A MUCH QUIETER
NIGHT WEATHERWISE THAN LAST NIGHT.
MODELS ARE IN FAIRLY GOOD AGREEMENT THROUGH THE UPCOMING WEEK. THE
BIGGEST DISAGREEMENT IS THAT THE NAM SHOWS A LITTLE MORE
PRECIPITATION AND IS FURTHER NORTH WITH THE PRECIPITATION TONIGHT
THAN THE GFS AND ECMWF. VERY COLD WEATHER WILL CONTINUE THROUGH MUCH
OF THE WORK WEEK WITH ONE MORE THREAT OF FREEZING RAIN AND SLEET
TONIGHT.
FOR TODAY...CLOUDS ARE EXPECTED TO GRADUALLY BREAK UP THIS MORNING
LEAVING PARTIAL SUNSHINE ACROSS THE AREA BY THIS AFTERNOON. ANOTHER
PUSH OF MODIFIED POLAR AIR WILL MOVE INTO THE MIDSOUTH KEEPING IT
VERY COLD ACROSS MOST OF THE REGION. LEFT IN A SLIGHT CHANCE OF RAIN
IN ADVANCE OF THE NEXT SYSTEM ACROSS EXTREME SOUTHERN PORTIONS OF
NORTH MS THIS AFTERNOON...OTHERWISE IT WILL BE A DRY DAY ACROSS THE
MIDSOUTH.
FOR TONIGHT...WEAK SURFACE LOW PRESSURE WILL TRACK TO THE SOUTHEAST
OF THE MIDSOUTH. THIS PLACES THE MIDSOUTH ON THE NORTHWESTERN FRINGE
OF MOST OF THE PRECIPITATION WITH THE HIGHEST POPS AND AMOUNTS
FORECAST THROUGH NORTH MS. GENERALLY TOOK A COMPROMISE BETWEEN THE
VARIOUS MODELS. COLDER AIR WILL CONTINUE TO ADVECT INTO THE AREA
FROM THE NORTHWEST. AS A RESULT...PRECIPITATION WILL BE CHANGING TO
FREEZING RAIN AND SLEET FROM THE NORTHWEST. THERE IS A SLIGHT CHANCE
OF LIGHT SNOW NORTH OF INTERSTATE 40 MAINLY DUE TO AN UPPER LEVEL
TROUGH APPROACHING FROM THE WEST...LITTLE IF ANY ACCUMULATION OF
SNOW IS EXPECTED. ATTM...THINK THE BEST CHANCE FOR ANY ICE
ACCUMULATION FROM FREEZING RAIN AND SLEET WILL BE ALONG AND SOUTH OF
INTERSTATE 40 ACROSS PORTIONS OF WEST TENNESSEE...EAST CENTRAL
ARKANSAS AND NORTH MISSISSIPPI. A WINTER WEATHER ADVISORY MAY NEED
TO BE ISSUED FOR PORTIONS OF THIS AREA LATER TODAY...CONFIDENCE IS
NOT HIGH ENOUGH TO ISSUE AT THIS TIME. ANY ICE ACCUMULATIONS ARE
FORECAST TO BE LIGHT AND LESS THAN 1/10 OF AN INCH. PRECIPITATION
ACROSS MUCH OF NORTH MISSISSIPPI WILL BEGIN AS RAIN MIXED WITH
FREEZING RAIN IN SOME LOCATIONS...GRADUALLY BECOMING FREEZING RAIN
AND SLEET AS COLDER AIR PUSHES IN FROM THE NORTHWEST. ONLY MINOR
IF ANY ACCUMULATIONS OF SLEET ARE EXPECTED.
THE PRECIPITATION WILL MOVE EAST OF THE MIDSOUTH EARLY TUESDAY WITH
STRONG COLD HIGH PRESSURE SETTLING OVER THE MIDSOUTH. THE GOOD NEWS
IS THAT NO MORE PRECIPITATION IS FORECAST UNTIL FRIDAY. QUITE COLD
CONDITIONS ARE FORECAST WEDNESDAY MORNING UNDER MOSTLY CLEAR SKIES
WITH LOWS IN THE TEENS ACROSS A LARGE SECTION OF THE AREA. THE HIGH
PRESSURE SYSTEM WILL MOVE TO THE EAST DURING THE DAY WEDNESDAY WITH
SLIGHTLY LESS COLD TEMPERATURES...BUT DID NOT GO AS WARM AS THE MEX
GUIDANCE INDICATES. ANOTHER SURGE OF MODIFIED ARCTIC AIR WILL PUSH
INTO THE REGION WEDNESDAY NIGHT WITH THURSDAY MORNING FORECAST TO BE
THE COLDEST OF THE WEEK. LOW TEMPERATURES WILL DROP INTO THE TEENS
ACROSS MUCH OF THE AREA WITH LOWER TEENS FOR SOME AREAS. WILL NEED
TO MONITOR WIND CHILL READINGS AS THEY MAY DROP TO NEAR ZERO ACROSS
PORTIONS OF NORTHWEST TN.
A LARGE SCALE UPPER LEVEL TROUGH WILL APPROACH THE MIDSOUTH FROM THE
WEST FRIDAY BRINGING OUR NEXT CHANCE OF PRECIPITATION. AT THIS
TIME...INDICATIONS ARE THAT MOST IF NOT ALL OF THE PRECIPITATION
WILL BE RAIN BUT WILL NEED TO KEEP AN EYE ON THIS IN CASE IT DOES
NOT WARM UP AS QUICKLY AS EXPECTED...ESPECIALLY ACROSS NORTHERN
AREAS. THE UPPER LEVEL TROUGH WILL MOVE ACROSS THE REGION FRIDAY
NIGHT AND EARLY SATURDAY WITH WIDESPREAD RAIN. POPS WILL NEED TO BE
INCREASED IN LATER FORECASTS IF THESE MODEL TRENDS PERSIST. DRY AND
COOLER WEATHER IS FORECAST SUNDAY NIGHT AND MONDAY AS THE TROUGH
MOVES OFF TO THE EAST.
JCL
&&
.AVIATION...
12Z TAF CYCLE
LOW CONFIDENCE TAF FORECAST OVER THE NEXT 24 HOURS. MVFR CEILINGS
SHOULD GRADUALLY LIFT TO VFR CONDS THIS AFTERNOON...EXCEPT FOR TUP
WHERE MVFR CIGS WILL PREVAIL FOR MOST OF THE DAY. LOW AND MID
LEVEL MOISTURE WILL ADVANCE AHEAD OF A SURFACE LOW PRESSURE SYSTEM
THROUGHOUT THE DAY. EVENTUALLY RAIN WILL GRADUALLY SPREAD
NORTHWARD AND OVERRIDE COLD DRY AIR THAT IS MOVING SOUTHEASTWARD.
THIS WILL LEAD TO A CHANCE OF RA CHANGING OVER TO FZRA AND PL AT
MKL...MEM...AND TUP SOMETIME AFTER 03Z. WINDS WILL REMAIN FROM THE
NORTH 8-10 KTS THROUGH THE END OF THE TAF PERIOD. ALL TYPES OF
PRECIPITATION WILL COME TO AN END FOLLOWING THE END OF THIS CYCLE.
AC3
&&
.AVIATION...
&&
.PRELIMINARY POINT TEMPS/POPS...
MEM 36 24 36 23 / 10 40 10 10
MKL 36 22 35 18 / 10 40 10 10
JBR 32 20 31 19 / 10 20 10 10
TUP 40 29 40 23 / 10 80 10 10
&&
.MEG WATCHES/WARNINGS/ADVISORIES...
AR...NONE.
MO...NONE.
MS...NONE.
TN...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS MEMPHIS TN
1125 PM CST SUN DEC 8 2013
.UPDATE...AVIATION DISCUSSION.
&&
.PREV DISCUSSION... /ISSUED 844 PM CST SUN DEC 8 2013/
DISCUSSION...02 SURFACE ANALYSIS PLACES A WEAK QUASI-STATIONARY
BOUNDARY/SURFACE LOW NEAR THE LOUISIANA/MISSISSIPPI/ALABAMA GULF
COAST THIS EVENING. MEANWHILE...A RIDGE OF HIGH PRESSURE IS
LOCATED ACROSS PORTIONS OF THE MIDDLE MISSISSIPPI VALLEY INTO
PORTIONS OF THE MID SOUTH. TEMPERATURES AS OF 8 PM CST RANGE FROM
THE MIDDLE 30S TO AROUND 40 DEGREES ACROSS WEST TENNESSEE NEAR THE
TENNESSEE RIVER AND PORTIONS OF NORTHEAST MISSISSIPPI AND UPPER
20S TO LOWER 30S ALONG AND WEST OF THE MISSISSIPPI RIVER.
KNQA/KGWX WSR-88D RADAR TRENDS INDICATE LIGHT RAIN SHOWERS ACROSS
NORTHEAST MISSISSIPPI IN ASSOCIATION WITH A MID LEVEL SHORTWAVE
TROUGH AND AN UPPER LEVEL JET STREAK MOVING ACROSS THE REGION.
LATEST RUC SHORT TERM MODEL SEEMS TO BE HANDLING CURRENT TRENDS
THE BEST WITH RESPECT TO PRECIPITATION. WILL MAKE ADJUSTMENTS TO
LIMIT AND LOWER PRECIPITATION CHANCES OVERNIGHT TO EXTREME
NORTHEAST MISSISSIPPI.
AS OF 8 PM CST...VISIBILITIES ARE CURRENTLY RANGING FROM 4SM TO
P6SM. LIGHT WINDS HAVE KEPT LOW LEVEL MOISTURE LIFTED AS A LOW
STRATUS LAYER THUS FAR. WILL CONTINUE TO MONITOR SHORT TERM TRENDS
FOR THE POSSIBLE DEVELOPMENT OF FOG/FREEZING FOG AND ANY HEADLINES
IF IT BECOMES NECESSARY.
WILL ALSO MAKE MINOR ADJUSTMENTS TO TEMPERATURES AND ALL OTHER
ELEMENTS AS NEEDED TO ACCOUNT FOR LATEST TRENDS.
UPDATED GRIDS WILL BE AVAILABLE SHORTLY.
CJC
PREV DISCUSSION... /ISSUED 536 PM CST SUN DEC 8 2013/
UPDATE...AVIATION DISCUSSION.
PREV DISCUSSION... /ISSUED 320 PM CST SUN DEC 8 2013/
A SHARP TEMPERATURE GRADIENT IS OCCURRING ACROSS THE MIDSOUTH
THIS EVENING. LOCATIONS SOUTH AND EAST OF A MEMPHIS TO JACKSON
TENNESSEE LINE ARE REPORTING TEMPERATURES IN THE MID 30S TO LOWER
40S. NORTH AND WEST OF THIS LINE TEMPERATURES RANGE FROM 28-32
DEGREES. TEMPERATURES ALSO REMAIN NEAR FREEZING FARTHER SOUTH IN
THE DELTA SUCH AS MARIANNA...TUNICA AND CLARKSDALE. PATCHY DENSE
FREEZING FOG HAS FORMED ALONG THIS GRADIENT BETWEEN THE ARCTIC AIR
AND THE WARMER AIR. WEST
MEMPHIS...MILLINGTON...BLYTHEVILLE...DYERSBURG AND UNION CITY ARE
REPORTING VISIBILITIES FROM A QUARTER MILE TO THREE QUARTERS OF A
MILE. THUS FAR NO ICING HAS OCCURRED AS A RESULT OF THE FOG BUT A
LITTLE WORRIED THAT THIS MAY CHANGE ONCE THE SUN GOES DOWN. WILL
LET EVENING SHIFT MONITOR FOR ANY POTENTIAL ADVISORIES.
MEANWHILE...RAIN CONTINUES TO PUSH NORTHWARD INTO NORTH
MISSISSIPPI WHERE LOCATIONS ARE ABOVE FREEZING. THIS IS DUE TO A
SFC LOW DEVELOPING ALONG A STATIONARY FRONT NEAR THE GULF COAST.
MODELS INDICATE THE NORTHERN EXTENT OF THE PRECIPITATION COULD
REACH INTO LOCATIONS THIS EVENING THAT ARE SITTING JUST ABOVE OR
AT FREEZING CURRENTLY. AS TEMPERATURES DROP THIS EVENING THIS
COULD CHANGE RAIN OVER TO FREEZING RAIN...BUT CONFIDENCE IS LOW
THUS AGAIN WILL LET EVENING SHIFT MONITOR FOR ANY POTENTIAL
ADVISORIES. WILL JUST MENTION A SLIGHT CHANCE OR CHANCE OF
FREEZING RAIN IN THE FORECAST AS BEST CHANCES OF PRECIPITATION
WILL OCCUR ACROSS NORTHEAST MISSISSIPPI WHERE LOCATIONS WILL
REMAIN ABOVE FREEZING.
ANOTHER SFC LOW WILL DEVELOP ALONG THE STATIONARY FRONT LOCATED
ALONG THE GULF COAST BY MONDAY EVENING. THIS WILL BRING ANOTHER
ROUND OF PRECIPITATION THAT WILL SKIRT NORTHEAST MISSISSIPPI.
HOWEVER BY MONDAY EVENING...NORTHWEST WINDS WILL HAVE PUSHED
ARCTIC AIR FURTHER SOUTH AND EAST THUS PRECIPITATION COULD FALL IN
THE FORM OF FREEZING RAIN IF PRECIPITATION MAKES IT AS FAR NORTH
AS NORTHEAST MISSISSIPPI. STAY TUNED.
IN ADDITION...A SHORTWAVE WILL SWING ACROSS SOUTHERN MISSOURI AND
WESTERN KENTUCKY MONDAY NIGHT. THIS COULD BRING A BRIEF SHOT OF LIGHT
SNOW ACROSS PORTIONS OF NORTHEAST ARKANSAS...THE MISSOURI BOOTHEEL
AND NORTHWEST TENNESSEE. ANY ACCUMULATIONS THAT WOULD OCCUR WOULD
BE LESS THAN AN INCH.
BY TUESDAY...ARCTIC HIGH PRESSURE SETTLES OVER THE MIDSOUTH.
EXPECT DRY CONDITIONS WITH HIGHS RANGING FROM THE LOWER 30S TO
LOWER 40S. A REINFORCING SHOT OF ARCTIC AIR WILL MOVE INTO THE
AREA ON WEDNESDAY INTO WEDNESDAY NIGHT. LOWS WEDNESDAY NIGHT WILL
RANGE FROM THE MID TEENS TO THE MID 20S.
BY THURSDAY NIGHT...THE HIGH WILL SHIFT EAST TURNING WINDS AROUND TO
THE SOUTH. THE NEXT LOW PRESSURE SYSTEM WILL MOVE INTO THE AREA ON
FRIDAY AND WILL BRING CHANCES FOR PRECIPITATION TO THE MIDSOUTH
OVER THE NEXT WEEKEND. HOW QUICKLY THE ARCTIC AIR DEPARTS WILL
DEPEND ON POSSIBLY PRECIPITATION TYPE FOR PORTIONS OF NEXT
WEEKEND. THE 12Z ECMWF IS COLDER THAN THE 12Z GFS. FOR NOW HAVE
TRIED TO GO WITH AN IN BETWEEN SOLUTION WHICH WOULD HAVE
TEMPERATURES NEAR NORMAL AND WOULD KEEP PRECIPITATION IN THE FORM
OF RAIN.
KRM
.AVIATION...06Z TAF CYCLE
VIS HAS IMPROVED TO MVFR LEVELS OR HIGHER AT ALL SITES BUT CIGS
REMAIN IFR EVERYWHERE EXCEPT JBR. NOT AS CONFIDENT THAT WE WILL
SEE THE LIFR CIGS WE HAD IN PREVIOUS ISSUANCES. FEEL LIKE WE WILL
SEE OVERALL SLOWLY IMPROVING CIGS WITH NEAR STEADY VIS FOR THE
REMAINDER OF THE NIGHT. GUIDANCE WANTS TO CONTINUE TO LIFT CIGS
THROUGH THE DAY EVEN TO VFR LEVELS...BASED ON EXPERIENCE...FEEL
LIKE CLOUDS WILL LINGER LONGER THAN GUIDANCE SUGGESTS...BUT WILL
BRING LEVELS TO 5KFT DURING THE AFTERNOON FOR ALL LOCATIONS EXCEPT
TUP.
RAIN AT TUP WILL BE LIGHT...WITH LITTLE TO NO PRECIPITATION
ELSEWHERE. SOME PATCHY DRIZZLE MAY DEVELOP...AND MEM IS CURRENTLY
REPORTING -DZ BUT DO NOT FEEL LIKE THIS WILL BE A PREVAILING
CONDITION. WINDS GENERALLY LIGHT OVERNIGHT...LIGHT FROM THE NORTH
TOMORROW. SOME LIGHT RAIN MAY MOVE BACK NEAR TUP LATE TOMORROW.
JDS
&&
.PRELIMINARY POINT TEMPS/POPS...
MEM 31 39 27 38 / 40 10 20 10
MKL 31 38 24 37 / 50 10 20 10
JBR 25 31 24 32 / 10 10 20 10
TUP 37 43 33 42 / 80 30 60 10
&&
.MEG WATCHES/WARNINGS/ADVISORIES...
AR...NONE.
MO...NONE.
MS...NONE.
TN...NONE.
&&
$$
AREA FORECAST DISCUSSION...UPDATED
NWS SAN ANGELO TX
137 PM CST Mon Dec 9 2013
.UPDATE...
Quick update to continue patchy freezing fog for portions of the
Big Country this afternoon. Visibilities for the most part have
been improving but Abilene continues to see visibilities between
1/4 and 1/2 miles. Should see visibilities across this area
improve to around 2 miles within the next couple of hours.
Temperatures currently range from the upper 20s and and lower 30s
north of a San Angelo to San Saba line, with upper 30s generally
south of this line. Temperatures should remain nearly steady
through the rest of this afternoon and made adjustments to hourly
temperatures to account for this. No other changes needed at this
time.
&&
.PREV DISCUSSION... /ISSUED 1157 AM CST MON DEC 9 2013/
AVIATION...
/18Z TAFS/
Widespread stratus and FG/FZFG will persist across the terminals
this afternoon. Visibilities are beginning to improve late this
morning but latest guidance indicates IFR/LIFR CIGS persisting for
the remainder of the afternoon hours. The exception will be KSOA
where CIGS should remain mainly MVFR. Not much improvement expected
across the remaining terminals this evening with IFR CIGS continuing
through late evening. KABI will likely hold onto some MVFR
visibilities as well through the evening hours. Drier air filters
into the region overnight with skies clearing across the terminals
after 09Z.
PREV DISCUSSION... /ISSUED 753 AM CST MON DEC 9 2013/
UPDATE...
Expanded the Freezing Fog Advisory another row of counties.
DISCUSSION...
The fog continues to expand into the Concho Valley, so I have
expanded the Freezing Fog Advisory to include Irion, Tom Green,
Concho, Menard, and Schleicher counties. We will continue to monitor
to progress of the fog.
PREV DISCUSSION... /ISSUED 554 AM CST MON DEC 9 2013/
UPDATE...
To expand the Freezing Fog Advisory...
DISCUSSION...
Areas of freezing fog across the Big Country, Heartland and
Northwest Hill country continue to expand to the south and west.
Temperatures are below freezing across the entire area and given
the expansion of the fog, I went ahead and expanded the advisory
to include all of the Big Country and the northern Concho Valley.
The freezing fog could approach areas farther south in the next
few hours, including San Angelo, so I will continue to monitor
trends and these counties may need to eventually be added.
Otherwise, the rest of the forecast looks on track.
Please see the aviation discussion below...
AVIATION...
Stratus/fog continues to expand through much of West Central Texas
this morning resulting in IFR to LIFR conditions. KSOA is a bit
more tricky, as the stratus to the south is struggling to expand
northward. For now, I have indicated MVFR ceilings by 14z, and
will continue to monitor. Some improvement in ceilings is forecast
by late morning or early afternoon, with MVFR ceilings returning
to most sites. Winds today will be from the north at 5 to 10 knots
PREV DISCUSSION... /ISSUED 356 AM CST MON DEC 9 2013/
SHORT TERM...
Today and Tonight
A cold front is currently moving through the Big Country and
should be approaching the Interstate 10 corridor shortly after
sunrise. Winds behind the front will become north and increase to
about 8 to 12 mph, with colder air slowly filtering into West
Central Texas. In addition, areas of freezing fog are evident just
to the east of our area, which has slowly been creeping west. I
expect this freezing fog to expand to a Throckmorton, to Coleman,
to Mason line in the next few hours. A freezing fog advisory is in
effect for parts of the Heartland through 9 AM, and I will
continue to monitor trends for the possibility of expanding it
north into parts of the Big Country and south toward Mason county.
The HRRR is also indicating some post frontal fog across parts of
the Big Country, which will need to be monitored. Stratus should
fill in this morning behind the front, with much of the area
becoming overcast by mid morning. Given the expected cloud cover
and cold air advection, I lowered high temperatures slightly.
Highs will range from the upper 20s north of Interstate 20, to the
mid 40s across the Interstate 10 corridor.
Cloudy skies through much of the overnight period will not
support ideal radiational cooling conditions, but given the cold
airmass that will be filtering into the region, I went ahead and
lowered low temperatures slightly. Tuesday morning low
temperatures will generally be in the teens to lower 20s across
all of West Central Texas.
Daniels
LONG TERM...
Tuesday through Sunday
As a fast moving shortwave trough moves through the Great Lakes
region Tuesday night into Wednesday, a cold front will move into
Texas, causing another brief cooling for Wednesday into Thursday.
However, no precipitation is expected with the front. Lee
troughing on Thursday will allow winds to quickly turn back to the
south in our area, allowing temperatures to warm back up across
the area Thursday and especially Friday. An upper level low
initially off the coast of California on Monday will move across
the Desert Southwest and into the Texas panhandle by Friday. As
this low approaches, weak shortwaves will move across the area out
ahead of it, interacting with moisture return and low level warm
air advection, resulting in at least a slight chance for showers
mainly Thursday afternoon and Thursday night, with some lingering
showers moving out of the area on Friday.
The upper level low will then move east towards the Mississippi
Valley by Saturday, sending a cold front into the area. And while
the cold front will slow the warming trend, the air mass behind
the front will not be of arctic origin, so while we have gone
cooler than the MOS guidance for Saturday and Sunday, temperatures
should continue to trend closer to normal values through the
weekend.
20
&&
.PRELIMINARY POINT TEMPS/POPS...
Abilene 29 17 40 27 41 / 10 5 0 0 0
San Angelo 33 21 44 26 47 / 10 5 0 0 0
Junction 41 23 47 24 53 / 10 5 0 0 0
&&
.SJT WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
99/99
AREA FORECAST DISCUSSION
NWS SAN ANGELO TX
1157 AM CST MON DEC 9 2013
.AVIATION...
/18Z TAFS/
Widespread stratus and FG/FZFG will persist across the terminals
this afternoon. Visibilities are beginning to improve late this
morning but latest guidance indicates IFR/LIFR CIGS persisting for
the remainder of the afternoon hours. The exception will be KSOA
where CIGS should remain mainly MVFR. Not much improvement expected
across the remaining terminals this evening with IFR CIGS continuing
through late evening. KABI will likely hold onto some MVFR
visibilities as well through the evening hours. Drier air filters
into the region overnight with skies clearing across the terminals
after 09Z.
&&
.PREV DISCUSSION... /ISSUED 753 AM CST MON DEC 9 2013/
UPDATE...
Expanded the Freezing Fog Advisory another row of counties.
DISCUSSION...
The fog continues to expand into the Concho Valley, so I have
expanded the Freezing Fog Advisory to include Irion, Tom Green,
Concho, Menard, and Schleicher counties. We will continue to monitor
to progress of the fog.
PREV DISCUSSION... /ISSUED 554 AM CST MON DEC 9 2013/
UPDATE...
To expand the Freezing Fog Advisory...
DISCUSSION...
Areas of freezing fog across the Big Country, Heartland and
Northwest Hill country continue to expand to the south and west.
Temperatures are below freezing across the entire area and given
the expansion of the fog, I went ahead and expanded the advisory
to include all of the Big Country and the northern Concho Valley.
The freezing fog could approach areas farther south in the next
few hours, including San Angelo, so I will continue to monitor
trends and these counties may need to eventually be added.
Otherwise, the rest of the forecast looks on track.
Please see the aviation discussion below...
AVIATION...
Stratus/fog continues to expand through much of West Central Texas
this morning resulting in IFR to LIFR conditions. KSOA is a bit
more tricky, as the stratus to the south is struggling to expand
northward. For now, I have indicated MVFR ceilings by 14z, and
will continue to monitor. Some improvement in ceilings is forecast
by late morning or early afternoon, with MVFR ceilings returning
to most sites. Winds today will be from the north at 5 to 10 knots
PREV DISCUSSION... /ISSUED 356 AM CST MON DEC 9 2013/
SHORT TERM...
Today and Tonight
A cold front is currently moving through the Big Country and
should be approaching the Interstate 10 corridor shortly after
sunrise. Winds behind the front will become north and increase to
about 8 to 12 mph, with colder air slowly filtering into West
Central Texas. In addition, areas of freezing fog are evident just
to the east of our area, which has slowly been creeping west. I
expect this freezing fog to expand to a Throckmorton, to Coleman,
to Mason line in the next few hours. A freezing fog advisory is in
effect for parts of the Heartland through 9 AM, and I will
continue to monitor trends for the possibility of expanding it
north into parts of the Big Country and south toward Mason county.
The HRRR is also indicating some post frontal fog across parts of
the Big Country, which will need to be monitored. Stratus should
fill in this morning behind the front, with much of the area
becoming overcast by mid morning. Given the expected cloud cover
and cold air advection, I lowered high temperatures slightly.
Highs will range from the upper 20s north of Interstate 20, to the
mid 40s across the Interstate 10 corridor.
Cloudy skies through much of the overnight period will not
support ideal radiational cooling conditions, but given the cold
airmass that will be filtering into the region, I went ahead and
lowered low temperatures slightly. Tuesday morning low
temperatures will generally be in the teens to lower 20s across
all of West Central Texas.
Daniels
LONG TERM...
Tuesday through Sunday
As a fast moving shortwave trough moves through the Great Lakes
region Tuesday night into Wednesday, a cold front will move into
Texas, causing another brief cooling for Wednesday into Thursday.
However, no precipitation is expected with the front. Lee
troughing on Thursday will allow winds to quickly turn back to the
south in our area, allowing temperatures to warm back up across
the area Thursday and especially Friday. An upper level low
initially off the coast of California on Monday will move across
the Desert Southwest and into the Texas panhandle by Friday. As
this low approaches, weak shortwaves will move across the area out
ahead of it, interacting with moisture return and low level warm
air advection, resulting in at least a slight chance for showers
mainly Thursday afternoon and Thursday night, with some lingering
showers moving out of the area on Friday.
The upper level low will then move east towards the Mississippi
Valley by Saturday, sending a cold front into the area. And while
the cold front will slow the warming trend, the air mass behind
the front will not be of arctic origin, so while we have gone
cooler than the MOS guidance for Saturday and Sunday, temperatures
should continue to trend closer to normal values through the
weekend.
20
&&
.PRELIMINARY POINT TEMPS/POPS...
Abilene 26 18 39 27 42 / 10 5 0 0 0
San Angelo 35 19 44 26 46 / 10 5 0 0 0
Junction 46 22 47 24 52 / 10 10 5 0 0
&&
.SJT WATCHES/WARNINGS/ADVISORIES...
FREEZING FOG ADVISORY until Noon CST today FOR THE FOLLOWING
ZONES: Brown...Callahan...Coke...Coleman...Concho...Fisher...
Haskell...Irion...Jones...Kimble...Mason...McCulloch...Menard...
Nolan...Runnels...San Saba...Schleicher...Shackelford...
Sterling...Taylor...Throckmorton...Tom Green.
&&
$$
24
AREA FORECAST DISCUSSION...UPDATED
NWS MIDLAND/ODESSA TX
912 AM CST Mon Dec 9 2013
.DISCUSSION...
Have opted to issue a freezing fog advisory for most of the Basin
including Lea County until 18z. Vsbys are being reported as low as
1/8 mile here at MAF and 1/4 mile at Andrews. Also, flurries are
being reported in Midland/Greenwood/Snyder and have mentioned that in
fcst too.
&&
.PREV DISCUSSION... /ISSUED 734 AM CST Mon Dec 9 2013/
UPDATE...
Have sent an update to include mention of Freezing fog across most
of the PB and Lea Co.
DISCUSSION...
Cold air is pushing swd and areas of freezing fog are developing in
the colder air. Big Spring and Snyder are down to 3/4 to 1 1/4 miles
visibility. NAM12 is a little too cool and RUC13 a little too warm
looking at dwpnts upstream IT will still take a few hrs for dwpnts
to decrease and thus fog expected to hang around thru at least mid
morning. Very light ice accumulations possible.
PREV DISCUSSION... /ISSUED 506 AM CST Mon Dec 9 2013/
DISCUSSION...
See aviation discussion below.
AVIATION...
Cold front currently moving southwest through the northern Permian
Basin. Expecting prevailing to tempo MVFR to IFR conditions behind
this front today. A period of VFR conditions is possible this afternoon
at the terminals before MVFR and or IFR conditions return early
this evening and continuing overnight. Generally northeast winds
of 5 to 15 mph are expected through this evening.
12
PREV DISCUSSION... /ISSUED 355 AM CST Mon Dec 9 2013/
DISCUSSION...
Another cold front is moving through the area early this morning
bringing a resurgence of very cold air. We are not seeing any
freezing fog so far either ahead of or behind the front, and
despite mostly clear skies and low T/Td depressions, concern is
dropping for a serious freezing fog threat. It is still possible
for some patchy freezing fog to form especially near the leading
edge of the front with the fog threat diminishing farther behind
the front as drier air filters south. The small T/Td depressions
could allow for some ice condensation to occur on exposed surfaces
despite the lack of fog creating slick spots on local roads.
Models have backed off snow chances in SE NM today and tonight
likely due to limited moisture and a very positively tilted weak
upper trough so have removed PoPs.
We then see slightly warmer temps Tuesday and Wednesday before a
weak front arrives Thursday. A more zonal upper air pattern will
limit the amount of cold air. Shortly following this front will be
an upper level low moving out of the southwestern states. This low
will be weakening as it approaches the area and may even be an
open trough by the time it arrives over west Texas, but there
should be enough moisture and instability for precipitation to
develop Thursday. The amount and extent of precipitation will
depend greatly on the strength of the upper low...the stronger the
low the more likely it is the precip will spread farther west...a
weak low or trough will push moisture and most precip to the
eastern CWA. For now the consensus seems to be that it will be an
open trough and thus will keep precip chances to the eastern
counties. Temperatures at this time indicate the p-type would be
rain so there may not be any travel worries this time. Friday gets
warmer before yet another front arrives Saturday.
Hennig
&&
.PRELIMINARY POINT TEMPS/POPS...
ANDREWS TX 29 18 43 25 / 10 10 0 0
BIG SPRING TX 28 18 44 26 / 10 10 0 0
CARLSBAD NM 42 25 48 27 / 10 10 0 0
DRYDEN TX 51 27 49 30 / 0 0 0 0
FORT STOCKTON TX 46 22 50 29 / 0 10 0 0
GUADALUPE PASS TX 44 22 44 28 / 10 10 0 0
HOBBS NM 32 17 45 24 / 10 10 0 0
MARFA TX 53 22 50 26 / 0 10 0 0
MIDLAND INTL AIRPORT TX 32 18 44 25 / 10 10 0 0
ODESSA TX 32 19 45 26 / 10 10 0 0
WINK TX 39 22 47 25 / 10 10 0 0
&&
.MAF WATCHES/WARNINGS/ADVISORIES...
NM...FREEZING FOG ADVISORY until 11 AM MST this morning FOR THE
FOLLOWING ZONES... Central Lea County...Northern Lea
County...Southern Lea County.
TX...FREEZING FOG ADVISORY until Noon CST today FOR THE FOLLOWING
ZONES... Andrews...Borden...Dawson...Ector...Gaines...
Glasscock...Howard...Martin...Midland...Mitchell...Scurry...
Winkler.
&&
$$
AREA FORECAST DISCUSSION
NWS SAN ANGELO TX
753 AM CST MON DEC 9 2013
.UPDATE...
Expanded the Freezing Fog Advisory another row of counties.
&&
.DISCUSSION...
The fog continues to expand into the Concho Valley, so I have
expanded the Freezing Fog Advisory to include Irion, Tom Green,
Concho, Menard, and Schleicher counties. We will continue to monitor
to progress of the fog.
&&
.PREV DISCUSSION... /ISSUED 554 AM CST MON DEC 9 2013/
UPDATE...
To expand the Freezing Fog Advisory...
DISCUSSION...
Areas of freezing fog across the Big Country, Heartland and
Northwest Hill country continue to expand to the south and west.
Temperatures are below freezing across the entire area and given
the expansion of the fog, I went ahead and expanded the advisory
to include all of the Big Country and the northern Concho Valley.
The freezing fog could approach areas farther south in the next
few hours, including San Angelo, so I will continue to monitor
trends and these counties may need to eventually be added.
Otherwise, the rest of the forecast looks on track.
Please see the aviation discussion below...
AVIATION...
Stratus/fog continues to expand through much of West Central Texas
this morning resulting in IFR to LIFR conditions. KSOA is a bit
more tricky, as the stratus to the south is struggling to expand
northward. For now, I have indicated MVFR ceilings by 14z, and
will continue to monitor. Some improvement in ceilings is forecast
by late morning or early afternoon, with MVFR ceilings returning
to most sites. Winds today will be from the north at 5 to 10 knots
PREV DISCUSSION... /ISSUED 356 AM CST MON DEC 9 2013/
SHORT TERM...
Today and Tonight
A cold front is currently moving through the Big Country and
should be approaching the Interstate 10 corridor shortly after
sunrise. Winds behind the front will become north and increase to
about 8 to 12 mph, with colder air slowly filtering into West
Central Texas. In addition, areas of freezing fog are evident just
to the east of our area, which has slowly been creeping west. I
expect this freezing fog to expand to a Throckmorton, to Coleman,
to Mason line in the next few hours. A freezing fog advisory is in
effect for parts of the Heartland through 9 AM, and I will
continue to monitor trends for the possibility of expanding it
north into parts of the Big Country and south toward Mason county.
The HRRR is also indicating some post frontal fog across parts of
the Big Country, which will need to be monitored. Stratus should
fill in this morning behind the front, with much of the area
becoming overcast by mid morning. Given the expected cloud cover
and cold air advection, I lowered high temperatures slightly.
Highs will range from the upper 20s north of Interstate 20, to the
mid 40s across the Interstate 10 corridor.
Cloudy skies through much of the overnight period will not
support ideal radiational cooling conditions, but given the cold
airmass that will be filtering into the region, I went ahead and
lowered low temperatures slightly. Tuesday morning low
temperatures will generally be in the teens to lower 20s across
all of West Central Texas.
Daniels
LONG TERM...
Tuesday through Sunday
As a fast moving shortwave trough moves through the Great Lakes
region Tuesday night into Wednesday, a cold front will move into
Texas, causing another brief cooling for Wednesday into Thursday.
However, no precipitation is expected with the front. Lee
troughing on Thursday will allow winds to quickly turn back to the
south in our area, allowing temperatures to warm back up across
the area Thursday and especially Friday. An upper level low
initially off the coast of California on Monday will move across
the Desert Southwest and into the Texas panhandle by Friday. As
this low approaches, weak shortwaves will move across the area out
ahead of it, interacting with moisture return and low level warm
air advection, resulting in at least a slight chance for showers
mainly Thursday afternoon and Thursday night, with some lingering
showers moving out of the area on Friday.
The upper level low will then move east towards the Mississippi
Valley by Saturday, sending a cold front into the area. And while
the cold front will slow the warming trend, the air mass behind
the front will not be of arctic origin, so while we have gone
cooler than the MOS guidance for Saturday and Sunday, temperatures
should continue to trend closer to normal values through the
weekend.
20
&&
.PRELIMINARY POINT TEMPS/POPS...
Abilene 26 18 39 27 42 / 10 5 0 0 0
San Angelo 35 19 44 26 46 / 10 5 0 0 0
Junction 46 22 47 24 52 / 10 10 5 0 0
&&
.SJT WATCHES/WARNINGS/ADVISORIES...
FREEZING FOG ADVISORY until 10 AM CST this morning FOR THE
FOLLOWING ZONES: Brown...Callahan...Coke...Coleman...Concho...
Fisher...Haskell...Irion...Jones...Kimble...Mason...McCulloch...
Menard...Nolan...Runnels...San Saba...Schleicher...Shackelford...
Sterling...Taylor...Throckmorton...Tom Green.
&&
$$
Reimer
AREA FORECAST DISCUSSION...UPDATE
NWS MIDLAND/ODESSA TX
734 AM CST Mon Dec 9 2013
.UPDATE...
Have sent an update to include mention of Freezing fog across most
of the PB and Lea Co.
&&
.DISCUSSION...
Cold air is pushing swd and areas of freezing fog are developing in
the colder air. Big Spring and Snyder are down to 3/4 to 1 1/4 miles
visibility. NAM12 is a little too cool and RUC13 a little too warm
looking at dwpnts upstream IT will still take a few hrs for dwpnts
to decrease and thus fog expected to hang around thru at least mid
morning. Very light ice accumulations possible.
&&
.PREV DISCUSSION... /ISSUED 506 AM CST Mon Dec 9 2013/
DISCUSSION...
See aviation discussion below.
AVIATION...
Cold front currently moving southwest through the northern Permian
Basin. Expecting prevailing to tempo MVFR to IFR conditions behind
this front today. A period of VFR conditions is possible this afternoon
at the terminals before MVFR and or IFR conditions return early
this evening and continuing overnight. Generally northeast winds
of 5 to 15 mph are expected through this evening.
12
PREV DISCUSSION... /ISSUED 355 AM CST Mon Dec 9 2013/
DISCUSSION...
Another cold front is moving through the area early this morning
bringing a resurgence of very cold air. We are not seeing any
freezing fog so far either ahead of or behind the front, and
despite mostly clear skies and low T/Td depressions, concern is
dropping for a serious freezing fog threat. It is still possible
for some patchy freezing fog to form especially near the leading
edge of the front with the fog threat diminishing farther behind
the front as drier air filters south. The small T/Td depressions
could allow for some ice condensation to occur on exposed surfaces
despite the lack of fog creating slick spots on local roads.
Models have backed off snow chances in SE NM today and tonight
likely due to limited moisture and a very positively tilted weak
upper trough so have removed PoPs.
We then see slightly warmer temps Tuesday and Wednesday before a
weak front arrives Thursday. A more zonal upper air pattern will
limit the amount of cold air. Shortly following this front will be
an upper level low moving out of the southwestern states. This low
will be weakening as it approaches the area and may even be an
open trough by the time it arrives over west Texas, but there
should be enough moisture and instability for precipitation to
develop Thursday. The amount and extent of precipitation will
depend greatly on the strength of the upper low...the stronger the
low the more likely it is the precip will spread farther west...a
weak low or trough will push moisture and most precip to the
eastern CWA. For now the consensus seems to be that it will be an
open trough and thus will keep precip chances to the eastern
counties. Temperatures at this time indicate the p-type would be
rain so there may not be any travel worries this time. Friday gets
warmer before yet another front arrives Saturday.
Hennig
&&
.PRELIMINARY POINT TEMPS/POPS...
ANDREWS TX 29 18 43 25 / 10 10 0 0
BIG SPRING TX 28 18 44 26 / 10 10 0 0
CARLSBAD NM 42 25 48 27 / 10 10 0 0
DRYDEN TX 51 27 49 30 / 0 0 0 0
FORT STOCKTON TX 46 22 50 29 / 0 10 0 0
GUADALUPE PASS TX 44 22 44 28 / 10 10 0 0
HOBBS NM 32 17 45 24 / 10 10 0 0
MARFA TX 53 22 50 26 / 0 10 0 0
MIDLAND INTL AIRPORT TX 32 18 44 25 / 10 10 0 0
ODESSA TX 32 19 45 26 / 10 10 0 0
WINK TX 39 22 47 25 / 10 10 0 0
&&
.MAF WATCHES/WARNINGS/ADVISORIES...
NM...NONE.
TX...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS SAN ANGELO TX
554 AM CST MON DEC 9 2013
.UPDATE...
To expand the Freezing Fog Advisory...
&&
.DISCUSSION...
Areas of freezing fog across the Big Country, Heartland and
Northwest Hill country continue to expand to the south and west.
Temperatures are below freezing across the entire area and given
the expansion of the fog, I went ahead and expanded the advisory
to include all of the Big Country and the northern Concho Valley.
The freezing fog could approach areas farther south in the next
few hours, including San Angelo, so I will continue to monitor
trends and these counties may need to eventually be added.
Otherwise, the rest of the forecast looks on track.
Please see the aviation discussion below...
&&
.AVIATION...
Stratus/fog continues to expand through much of West Central Texas
this morning resulting in IFR to LIFR conditions. KSOA is a bit
more tricky, as the stratus to the south is struggling to expand
northward. For now, I have indicated MVFR ceilings by 14z, and
will continue to monitor. Some improvement in ceilings is forecast
by late morning or early afternoon, with MVFR ceilings returning
to most sites. Winds today will be from the north at 5 to 10 knots
&&
.PREV DISCUSSION... /ISSUED 356 AM CST MON DEC 9 2013/
SHORT TERM...
Today and Tonight
A cold front is currently moving through the Big Country and
should be approaching the Interstate 10 corridor shortly after
sunrise. Winds behind the front will become north and increase to
about 8 to 12 mph, with colder air slowly filtering into West
Central Texas. In addition, areas of freezing fog are evident just
to the east of our area, which has slowly been creeping west. I
expect this freezing fog to expand to a Throckmorton, to Coleman,
to Mason line in the next few hours. A freezing fog advisory is in
effect for parts of the Heartland through 9 AM, and I will
continue to monitor trends for the possibility of expanding it
north into parts of the Big Country and south toward Mason county.
The HRRR is also indicating some post frontal fog across parts of
the Big Country, which will need to be monitored. Stratus should
fill in this morning behind the front, with much of the area
becoming overcast by mid morning. Given the expected cloud cover
and cold air advection, I lowered high temperatures slightly.
Highs will range from the upper 20s north of Interstate 20, to the
mid 40s across the Interstate 10 corridor.
Cloudy skies through much of the overnight period will not
support ideal radiational cooling conditions, but given the cold
airmass that will be filtering into the region, I went ahead and
lowered low temperatures slightly. Tuesday morning low
temperatures will generally be in the teens to lower 20s across
all of West Central Texas.
Daniels
LONG TERM...
Tuesday through Sunday
As a fast moving shortwave trough moves through the Great Lakes
region Tuesday night into Wednesday, a cold front will move into
Texas, causing another brief cooling for Wednesday into Thursday.
However, no precipitation is expected with the front. Lee
troughing on Thursday will allow winds to quickly turn back to the
south in our area, allowing temperatures to warm back up across
the area Thursday and especially Friday. An upper level low
initially off the coast of California on Monday will move across
the Desert Southwest and into the Texas panhandle by Friday. As
this low approaches, weak shortwaves will move across the area out
ahead of it, interacting with moisture return and low level warm
air advection, resulting in at least a slight chance for showers
mainly Thursday afternoon and Thursday night, with some lingering
showers moving out of the area on Friday.
The upper level low will then move east towards the Mississippi
Valley by Saturday, sending a cold front into the area. And while
the cold front will slow the warming trend, the air mass behind
the front will not be of arctic origin, so while we have gone
cooler than the MOS guidance for Saturday and Sunday, temperatures
should continue to trend closer to normal values through the
weekend.
20
&&
.PRELIMINARY POINT TEMPS/POPS...
Abilene 18 39 27 42 24 / 5 0 0 0 5
San Angelo 19 44 26 46 26 / 5 0 0 0 5
Junction 22 47 24 52 29 / 10 5 0 0 10
&&
.SJT WATCHES/WARNINGS/ADVISORIES...
FREEZING FOG ADVISORY until 10 AM CST this morning FOR THE
FOLLOWING ZONES: Brown...Callahan...Coke...Coleman...Fisher...
Haskell...Jones...Kimble...Mason...McCulloch...Nolan...Runnels...
San Saba...Shackelford...Sterling...Taylor...Throckmorton.
&&
$$
Daniels
AREA FORECAST DISCUSSION
NWS SAN ANGELO TX
356 AM CST MON DEC 9 2013
.SHORT TERM...
Today and Tonight
A cold front is currently moving through the Big Country and
should be approaching the Interstate 10 corridor shortly after
sunrise. Winds behind the front will become north and increase to
about 8 to 12 mph, with colder air slowly filtering into West
Central Texas. In addition, areas of freezing fog are evident just
to the east of our area, which has slowly been creeping west. I
expect this freezing fog to expand to a Throckmorton, to Coleman,
to Mason line in the next few hours. A freezing fog advisory is in
effect for parts of the Heartland through 9 AM, and I will
continue to monitor trends for the possibility of expanding it
north into parts of the Big Country and south toward Mason county.
The HRRR is also indicating some post frontal fog across parts of
the Big Country, which will need to be monitored. Stratus should
fill in this morning behind the front, with much of the area
becoming overcast by mid morning. Given the expected cloud cover
and cold air advection, I lowered high temperatures slightly.
Highs will range from the upper 20s north of Interstate 20, to the
mid 40s across the Interstate 10 corridor.
Cloudy skies through much of the overnight period will not
support ideal radiational cooling conditions, but given the cold
airmass that will be filtering into the region, I went ahead and
lowered low temperatures slightly. Tuesday morning low
temperatures will generally be in the teens to lower 20s across
all of West Central Texas.
Daniels
.LONG TERM...
Tuesday through Sunday
As a fast moving shortwave trough moves through the Great Lakes
region Tuesday night into Wednesday, a cold front will move into
Texas, causing another brief cooling for Wednesday into Thursday.
However, no precipitation is expected with the front. Lee
troughing on Thursday will allow winds to quickly turn back to the
south in our area, allowing temperatures to warm back up across
the area Thursday and especially Friday. An upper level low
initially off the coast of California on Monday will move across
the Desert Southwest and into the Texas panhandle by Friday. As
this low approaches, weak shortwaves will move across the area out
ahead of it, interacting with moisture return and low level warm
air advection, resulting in at least a slight chance for showers
mainly Thursday afternoon and Thursday night, with some lingering
showers moving out of the area on Friday.
The upper level low will then move east towards the Mississippi
Valley by Saturday, sending a cold front into the area. And while
the cold front will slow the warming trend, the air mass behind
the front will not be of arctic origin, so while we have gone
cooler than the MOS guidance for Saturday and Sunday, temperatures
should continue to trend closer to normal values through the
weekend.
20
&&
.PRELIMINARY POINT TEMPS/POPS...
Abilene 26 18 39 27 42 / 10 5 0 0 0
San Angelo 35 19 44 26 46 / 10 5 0 0 0
Junction 46 22 47 24 52 / 10 10 5 0 0
&&
.SJT WATCHES/WARNINGS/ADVISORIES...
FREEZING FOG ADVISORY until 9 AM CST this morning FOR THE
FOLLOWING ZONES: Brown...Callahan...Coleman...McCulloch...San
Saba.
&&
$$
AREA FORECAST DISCUSSION
NWS SAN ANGELO TX
1100 PM CST SUN DEC 8 2013
.UPDATE...
Areas of dense fog over Central TX continue to build back to the
west this evening and are right on the CWA border near San Saba and
Brownwood. Given extremely low dewpoint depressions, a general east
to southeast flow, and some residual sleet/ice pack on the ground, I
expect this westward trend to continue. BUFKIT hydrolapse analysis
of the NAM and RAP data indicate support this conceptual model.
Thus, I have issued a Freezing Fog Advisory for areas along and east
of a Baird, to Coleman, to Brady through 9 AM Monday. Visibilities
are already down to 1/4 mile at Lampasas and Hamilton and RH values
at Brownwood and Brady are greater than 93% currently. Given
sub-freezing temperatures, any areas of dense fog will likely result
in light ice accumulations on exposed surfaces. For aviation
impacts, see the aviation section below.
The remainder of the forecast package was in good shape. Minor
changes were made to overnight temperatures, with lows across the
Big Country increased by just a few degrees.
Johnson
&&
.AVIATION...
The forecast terminals will begin to the period with benign
conditions but I expected patchy freezing fog to develop overnight
across West Central TX. At this time, the greatest threat appears
to exist from KBWD to KBBD, but freezing fog will be possible at all
terminals later tonight. Visibilities are the lowest at KBBD with
only minor reductions forecast for the remaining forecast terminals.
In addition to the fog, an arctic cold front will move south across
West Central TX overnight, resulting in north to northeast winds of
8-12 kts and low ceilings. IFR ceilings are expected to develop late
tonight and persist through midday, gradually improving into MVFR
range during the afternoon and evening hours. Patchy, post-frontal
freezing drizzle is a concern but low confidence does not warrant a
mention in the current forecast package.
Johnson
&&
.PREV DISCUSSION... /ISSUED 540 PM CST SUN DEC 8 2013/
AVIATION...
Another shallow arctic cold front will move through West Central TX
late tonight and early Monday. Ahead of the cold front, we`ll see
light winds, generally from the south, under clear skies.
Sublimation over the sleet/ice pack will promote the development of
patchy fog (and freezing fog) tonight. Enough spatial uncertainty
exists that it extremely low visibilities will not be included in
the current TAF package. I did, however, reduce visibilities to 3-5
statute miles in most areas, but amendments may be required in areas
where fog does form as the forecast is likely too optimistic. Some
of this fog may lift into an IFR stratus deck as well.
As the front moves through the area, winds will shift to the north
at 8-10 kts and stratus is expected to become more widespread. I
would not rule out some patchy, post-frontal freezing drizzle.
Again, however, the relatively low probability does not warrant
mention in the TAF. I expect slow improvement in ceiling heights on
Monday afternoon as the cold air deepens and lift over the frontal
zone weakens.
Johnson
PREV DISCUSSION... /ISSUED 355 PM CST SUN DEC 8 2013/
SHORT TERM...
Tonight and Monday
Patchy freezing fog tonight and Arctic air Monday
Clearing skies and light winds may allow the development of patchy
freezing fog. This may potentially bring icing to bridges and
overpasses, mainly after midnight, as temperatures fall to the dew
point. Sleet from last week has been finally melting, with the
visible satellite imagery still indicating sleet on the ground from
the Big Country southward to San Angelo, Brady, and Brownwood. The
sleet will help moisten the boundary level tonight, further enhancing
the potential for fog.
An arctic cold front will move into the Big country, moving through
the I-20 corridor around 3 AM, and I-10 corridor around 9 AM. Low
level cloud development and mixing should dissipate the fog as the
arctic front moves through. Temperatures in the Big Country will
likely stay in the 20s Monday with wind chills in the single digits
in the morning. People should dress accordingly.
LONG TERM...
Monday Night through Sunday
Cold temperatures will continue Monday night and Tuesday with a
warming trend Wednesday through next weekend. A short wave trough
will move across the Southern Plains Monday night with surface high
pressure settling into the area into Tuesday. Temperatures will be
very cold Monday night with overnight lows falling into the upper
teens and lower 20s. The cold surface high will be overhead on
Tuesday and despite some sunshine, temperatures will remain well
below normal with afternoon highs ranging from the upper 30s along
and north of the I-20 corridor, to the lower 40s along the I-10
corridor.
By Wednesday, a broad upper level trough will cover much of the
country with a weak upper low developing over the Baja region.
A weak cold front will move across the area again on Wednesday
but the associated surface high and coldest airmass will remain
well northeast of the area through Thursday. Temperatures both
Wednesday and Thursday will continue to be well below normal but
will at least warm into the mid and upper 40s during the afternoon
hours, with a few low 50s possible along the I-10 corridor.
Southerly flow and increasing moisture return Thursday night and
Friday ahead of the approaching upper low over the Desert Southwest.
This system will bring a low chance of rainfall to mainly eastern
sections Thursday night and early Friday. Models show another upper
level trough and possible front affecting the area over the weekend
but this system looks dry. Expect warmer temperature Friday through
Sunday with highs in the 50s and lows in the 30s.
&&
.PRELIMINARY POINT TEMPS/POPS...
Abilene 20 28 17 38 24 / 0 5 5 0 5
San Angelo 25 37 20 43 24 / 0 5 5 5 5
Junction 28 45 23 45 24 / 5 10 10 5 5
&&
.SJT WATCHES/WARNINGS/ADVISORIES...
FREEZING FOG ADVISORY until 9 AM CST Monday FOR THE FOLLOWING
ZONES: Brown...Callahan...Coleman...McCulloch...San Saba.
&&
$$
25
AREA FORECAST DISCUSSION
NWS GREEN BAY WI
534 PM CST TUE DEC 10 2013
UPDATED AVIATION PORTION FOR 00Z TAF 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 00Z TAF ISSUANCE
ISSUED AT 533 PM CST TUE DEC 10 2013
ANOTHER IN A SERIES OF WEAK CLIPPER SYSTEMS WILL PASS OVER MAINLY
THE SOUTH HALF OF THE STATE AND NORTHERN ILLINOIS TONIGHT. EXPECT
MAINLY A PERIOD OF VFR CIGS WITH ISOLATED MVFR CIGS DURING PASSAGE
FOLLOWED BY ANOTHER SHOT OF COLD ARCTIC AIR WITH GUSTY WEST WINDS
FOR WEDNESDAY. DRIER AIR WILL DIMINISH CLOUDS QUICKLY FROM WEST TO
EAST FOR VFR CONDITIONS FOR WEDNESDAY.
&&
.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.......TDH
FORECAST DISCUSSION FOR ROUTINE AFTERNOON FORECAST 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 18Z TAF ISSUANCE
ISSUED AT 1128 AM CST MON DEC 9 2013
LIGHT SNOW AND FLURRIES ARE STUBBORNLY STICKING AROUND
CENTRAL AND NORTH-CENTRAL WISCONSIN AT MIDDAY...AND HAVE TO EXTEND
LOWER VSBYS IN LIGHT SNOW INTO MID-AFTERNOON. WEST WINDS WILL ALSO
REMAIN GUSTY THROUGH THE AFTERNOON BEFORE THE GUSTINESS SUBSIDES BY
EARLY THIS EVENING. A PERIOD OF VFR CONDITIONS WILL THEN FOLLOW
UNTIL LATE TONIGHT...AND THEN A FAST MOVING CLIPPER TYPE SYSTEM WILL
BRING A QUICK ROUND OF SNOW AND LOWERING CIGS LATE TONIGHT INTO
TUESDAY MORNING. VSBYS IN THE SNOW TO AT LEAST FALL INTO THE IFR
RANGE...AND POSSIBLY LOWER BASED ON OBSERVATIONS OVER MONTANA.
&&
.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.......MPC
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
1151 AM CST MON DEC 9 2013
.UPDATE...
ISSUED AT 1044 AM CST MON DEC 9 2013
TEMPERATURES HAVE NOT RISEN ACROSS PORTIONS OF SOUTHEAST MINNESOTA
AND NORTHEAST IOWA THIS MORNING WHILE WINDS HAVE CONTINUED TO
INCREASE TO AROUND 20 TO 30 MPH. THIS HAS LEAD TO WIND CHILLS
DROPPING INTO THE 20 TO 30 DEGREES BELOW ZERO RANGE. WITH
TEMPERATURES NOT EXPECTED TO CLIMB MUCH AT ALL...WILL BE ISSUING A
WIND CHILL ADVISORY FOR PORTIONS OF SE MN/NE IA THROUGH THIS
AFTERNOON. HAVE ALSO ADDED A FEW COUNTIES IN NORTHWEST WISCONSIN
TO THE ADVISORY AND STARTED THE NORTH CENTRAL COUNTIES RIGHT NOW
AS WELL SINCE TEMPERATURES ARE GOING TO CONTINUE TO DROP THERE AS
WELL. EXACT COUNTIES/TIMING IS CURRENTLY BEING WORKED ON WITH
NEIGHBORING OFFICES AND THE ADVISORY SHOULD BE POSTED SHORTLY.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 352 AM CST MON DEC 9 2013
MAIN SHORT TERM CONCERNS ARE ON TEMPERATURES...WIND CHILLS AND
POTENTIAL FOR MORE SNOW LATER TONIGHT.
CURRENTLY AS OF 08Z...WATER VAPOR LOOP AND RAP 500MB HEIGHT ANALYSIS
SHOWED A HIGHLY AMPLIFIED RIDGE OVER THE EASTERN PACIFIC...A DEEP
TROUGH FROM CENTRAL CANADA INTO THE FOUR CORNERS...AND RIDGING OVER
THE SOUTHEASTERN U.S.. WITHIN THE DEEP TROUGH THERE WERE 3
SHORTWAVES OF NOTE. THE FIRST WAS OVER SOUTHEAST WISCONSIN WHICH
HELPED BRING THE SNOW TO THE AREA YESTERDAY INTO THE EARLY MORNING
HOURS. MOST OF THE SNOW HAS PUSHED OFF TO THE EAST AS SHOWN BY RADAR
IMAGERY...IN RESPONSE TO SUBSIDENCE AND ISENTROPIC DESCENT IN THE
WAKE OF THE SHORTWAVE. THE SECOND SHORTWAVE OF NOTE WAS OVER THE
DAKOTAS. ALTHOUGH THIS SHORTWAVE WAS ONLY PRODUCING SOME ALTOSTRATUS
AHEAD OF IT...DUE TO DRY AIR SEEN ON THE 00Z BIS SOUNDING...THERE
WAS PLENTY OF COLD AIR WITH IT. 850MB TEMPS ACCORDING TO THE RAP ARE
-25C ACROSS NORTH DAKOTA...OR 2 STANDARD DEVIATIONS BELOW NORMAL.
FINALLY...THE THIRD SHORTWAVE WAS COMING DOWN THE BACK SIDE OF THE
TROUGH THROUGH CENTRAL ALBERTA. IMPRESSIVE 140KT JET AT THE
TROPOPAUSE ACCOMPANYING THE SHORTWAVE. ALREADY SOME LIGHT SNOW
FALLING JUST AHEAD OF THE SHORTWAVE.
A LOT OF RAPID MOTION FORECAST OVER THE NEXT 24 HOURS IN THE UPPER
LEVEL PATTERN...MOSTLY A RESULT FROM THAT STRONG UPPER JET CORE
COMING THROUGH ALBERTA. FIRST OFF...THE SHORTWAVE TROUGH OVER NORTH
DAKOTA IS PROGGED BY MODELS TO SLIDE THROUGH THE FORECAST AREA THIS
AFTERNOON. WE MAY SEE SOME MID OR HIGH CLOUDS PASS THROUGH AHEAD OF
THE SHORTWAVE...BUT THE BULK OF THE CLOUD COVER IS GOING TO BE THE
CURRENT STRATUS AFFECTING THE AREA. ANTICIPATING AS THE SHORTWAVE
PASSES...THE DRY ARCTIC AIR SEEN ACROSS NORTH DAKOTA CURRENTLY WILL
CLEAR OUT THE STRATUS. THIS MAY HAPPEN PRETTY QUICK WITH CLEARING
ALREADY COMING INTO THE FORECAST AREA. IN ADDITION...THAT SAME
ARCTIC AIR IS EXPECTED TO CAUSE TEMPERATURES TO FALL AS 850MB TEMPS
PLUMMET FROM THE CURRENT -14 TO -18C READINGS TO -18 TO -22C BY 21Z.
WINDS LOOK TO CRANK UP TOO AS THAT SHORTWAVE AND ASSOCIATED COLD AIR
COME IN. THESE WINDS...WITH GUSTS UPWARDS OF 20 TO 30 MPH...ARE
LIKELY TO CAUSE SOME BLOWING AND DRIFTING OF THE RECENT SNOW. AS
TEMPERATURES FALL THIS AFTERNOON...WIND CHILLS WILL BECOME MORE OF
AN ISSUE. TAYLOR/CLARK COUNTIES LOOK TO DROP INTO ADVISORY RANGE
AROUND 22Z AND DO NOT GET OUT UNTIL 12Z TUESDAY...THUS HAVE GONE
AHEAD AND ISSUED AN ADVISORY FOR THEM.
THE COLD AIR TONIGHT DOES NOT LAST LONG. MODELS ARE IN GOOD
AGREEMENT SHOWING THE ALBERTA SHORTWAVE DIGGING INTO THE DAKOTAS
THIS EVENING...THEN MOVING INTO THE FORECAST AREA TOWARDS 12Z. AS
THIS SHORTWAVE APPROACHES...WARM ADVECTION ENSUES...WITH 850MB TEMPS
CLIMBING UP TO -13 TO -17C BY 09Z. ALL INDICATIONS ARE THAT THE
ISENTROPIC LIFT AND SOME MOISTURE ADVECTION WILL CAUSE A MID CLOUD
DECK TO SPREAD ACROSS THE FORECAST AREA. THESE CLOUDS AND THE WARM
ADVECTION SHOULD RESULT IN RISING TEMPS LATE THIS EVENING INTO THE
OVERNIGHT...HELPING TO BRING WIND CHILLS UP. ADDITIONALLY...THE BEST
JUXTAPOSITION OF LOW LEVEL SATURATION AND ISENTROPIC LIFT OCCURS
NORTH OF INTERSTATE 90. GIVEN THE ARCTIC AIRMASS IN PLACE PRIOR TO
THE SHORTWAVE ARRIVAL...LIKELY WILL NOT TAKE MUCH TO SNOW. QPF MAY
NOT AMOUNT TO MUCH WITH THE COLD AIRMASS...MAYBE A COUPLE HUNDREDTHS
TOPS...BUT ENOUGH FORCING TO WARRANT HIGH PRECIPITATION CHANCES.
.LONG TERM...(TUESDAY THROUGH SUNDAY)
ISSUED AT 352 AM CST MON DEC 9 2013
MAIN LONG TERM FORECAST CONCERNS ARE ON TEMPERATURES...AS WELL AS
THE OSCILLATING DIURNAL TRENDS WITH THEM...AND POTENTIAL FOR
PRECIPITATION THROUGHOUT.
SHORTWAVE TROUGH COMING INTO THE FORECAST AREA TONIGHT QUICKLY MOVES
THROUGH DURING THE TUESDAY MORNING HOURS. ANY SNOW LOOKS TO DEPART
OFF TO THE EAST PRETTY FAST IN THE MORNING...FOLLOWED BY CLEARING
AND BRISK WEST WINDS. THESE WINDS COULD RESULT IN MORE BLOWING
SNOW...ESPECIALLY IF WE CAN GET A FEW TENTHS OUT OF TONIGHT.
ADDITIONALLY...THE WINDS DRIVE IN A BRIEF SURGE OF ARCTIC AIR WITH
850MB TEMPS FALLING TO -16 TO -20C BY 18Z. 09.00Z
ECMWF/NAM/CANADIAN/GFS THEN ALL DEPICT YET ANOTHER SHORTWAVE TROUGH
DROPPING INTO THE DAKOTAS TUESDAY NIGHT. AHEAD OF THIS
FEATURE...INCREASING ISENTROPIC LIFT AND MID LEVEL FRONTOGENESIS
LOOKS TO DEVELOP A BAND OF SNOW. POSITION OF THIS BAND OF SNOW IS
PROBLEMATIC...WITH THE ECMWF/NAM FARTHER NORTH COMPARED TO THE
GFS/CANADIAN. CONSENSUS WOULD SUGGEST LOCATIONS SOUTH OF I-90 WOULD
STAND TO SEE THE BEST CHANCE OF SEEING SNOW...SO RAISED CHANCES
TOWARDS 60 IN THIS AREA. THE BAND DOES APPEAR TO BE QUICK MOVING...
SUCH THAT BY 12Z WEDNESDAY...ITS ALREADY SOUTHEAST OF THE AREA.
NONETHELESS...WITH SNOW TO WATER RATIOS APPROACH 20 TO 1...WE COULD
SQUEEZE OUT AN INCH OR SO OUT OF THIS BAND.
JUST LIKE IN THE WAKE OF THE EVERY SHORTWAVE TROUGH...ANOTHER SURGE
OF ARCTIC AIR IS PROGGED TO FLOW INTO THE AREA ON WEDNESDAY WHEN THE
TROUGH MOVES THROUGH. 850MB TEMPS DROP TO -20 TO -24C AT 18Z
WEDNESDAY. THUS...DESPITE THAT SKIES SHOULD CLEAR ON WEDNESDAY AS
THE TROUGH COMES IN...IT WILL BE TOUGH TO WARM UP MUCH. MOST
LOCATIONS ARE LIKELY TO NOT GET OUT OF THE SINGLE DIGITS ABOVE
ZERO...AND NORTH OF HIGHWAY 10 MAY NOT EVEN GET TO ZERO. WITH THE
COLD TEMPS AND A NORTHWEST BREEZE...WIND CHILLS ARE YET AGAIN A
FACTOR WITH ANOTHER ADVISORY LIKELY NEEDED. NORTH OF HIGHWAY 10
APPEARS TO BE THE MOST LIKELY AREA FOR AN ADVISORY...STARTING LATE
TUESDAY NIGHT AND RUNNING THROUGH WEDNESDAY NIGHT. WEDNESDAY NIGHT
IS INTERESTING TOO. ALL MODELS ARE SUGGESTING RISING 500MB HEIGHTS
ACROSS THE CENTRAL PART OF THE COUNTRY. WARM ADVECTION ASSOCIATED
WITH THESE RISING HEIGHTS SHOULD CAUSE TEMPERATURES TO RISE...AFTER
A RAPID DROP OFF IN THE EVENING ASSOCIATED WITH A SURFACE RIDGE
PASSAGE. THERE MAY EVEN BE SOME SNOW THAT TRIES TO GET GOING NORTH
OF I-94...AS SUGGESTED BY THE ECMWF/CANADIAN AND HAVE INCLUDED 20
PERCENT CHANCES FOR THIS. THESE CHANCES PERSIST INTO THURSDAY. MUCH
WARMER 850MB TEMPS ON THURSDAY...ON THE ORDER OF -2 TO -8C BY
00Z...WILL RESULT IN HIGHS 15-20 DEGREES WARMER COMPARED TO
WEDNESDAY.
FROM THURSDAY NIGHT THROUGH SUNDAY...09.00Z ECMWF/GFS/CANADIAN
SUGGEST A NORTHWEST FLOW PATTERN IN THE MEAN...STRETCHING FROM
BRITISH COLUMBIA INTO THE GREAT LAKES. AT THE MOMENT THURSDAY NIGHT
LOOKS DRY. AS WE HEAD INTO FRIDAY AND ESPECIALLY FRIDAY
NIGHT...THERE ARE SUGGESTIONS A SOUTHERN STREAM SHORTWAVE TROUGH
COMING OUT OF THE CENTRAL PLAINS AND HEADING INTO THE OHIO VALLEY
COULD SPREAD SOME LIGHT SNOW INTO THE FORECAST AREA. THE CANADIAN IS
THE FARTHEST NORTHWEST AND DID HONOR THE SOLUTION WITH A 20 PERCENT
CHANCE. HOWEVER...THE 09.00Z GFS/ECMWF SUGGEST IT COULD STAY TO THE
SOUTHEAST...THUS SOMETHING TO MONITOR. HEADING INTO THE WEEKEND...
THE ECMWF/GFS SUGGEST A POTENT UPPER TROUGH WILL BE DROPPING SOUTH
INTO MANITOBA AND ONTARIO. THE ECMWF IS VERY AGGRESSIVE DIGGING IT
INTO WISCONSIN ON SUNDAY. FOR NOW STAYED WITH THE CONSENSUS WHICH
YIELDS A GENERALLY DRY SOLUTION WITH TEMPERATURES HOVERING SLIGHTLY
BELOW NORMAL. HOWEVER...SHOULD THE 00Z ECMWF BE CORRECT...
TEMPERATURES MAY NEED SIGNIFICANT LOWERING FOR SUNDAY.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z TUESDAY AFTERNOON)
ISSUED AT 1151 AM CST MON DEC 9 2013
THE COMBINATION OF GUSTY WINDS AND A FRESH SNOW PACK HAS RESULTED
IN SOME BLOWING SNOW IN SOUTHEAST MINNESOTA. THIS HAS CAUSED
VISIBILITIES TO DROP AT RST TO 2-3SM THIS MORNING AND THAT WILL
LIKELY CONTINUE INTO THE AFTERNOON BEFORE WINDS DROP OFF AROUND
SUNSET. SOME SCT-BKN MVFR CEILINGS HAVE BEEN OCCURRING ACROSS
WESTERN WISCONSIN AS TIMES AS WELL WITH LSE SEEMING TO BE ON THE
WESTERN EDGE OF IT.
WINDS WILL START TO COME AROUND TO THE SOUTHWEST THIS EVENING AS
THE NEXT SYSTEM APPROACHES FROM THE WEST. CEILINGS AND VISIBILITY
WILL DROP TO MVFR/IFR AS THE NEXT SNOW BAND COMES IN OVERNIGHT.
THE BEST TIMING FOR THIS SNOW APPEARS TO BE AROUND 9Z AT RST AND
11Z AT LSE AND SHOULD ONLY LAST FOR 2-4 HOURS AS THIS SYSTEM
QUICKLY MOVES THROUGH. WINDS WILL SHIFT BACK AROUND TO THE WEST
NORTHWEST AND BECOME GUSTY AGAIN AT 20-30KTS. THIS WILL LIKELY
LEAD TO SOME MORE BLOWING SNOW AND VISIBILITY REDUCTIONS AT RST
TOMORROW MORNING.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
WI...WIND CHILL ADVISORY UNTIL 6 PM CST THIS EVENING FOR WIZ032>034.
WIND CHILL ADVISORY UNTIL 6 AM CST TUESDAY FOR WIZ017-029.
MN...WIND CHILL ADVISORY UNTIL 6 PM CST THIS EVENING FOR MNZ079-
086>088-094-095.
IA...WIND CHILL ADVISORY UNTIL 6 PM CST THIS EVENING FOR IAZ008-009-
018-019.
&&
$$
UPDATE...HALBACH
SHORT TERM...AJ
LONG TERM...AJ
AVIATION...HALBACH
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
1044 AM CST MON DEC 9 2013
.UPDATE...
ISSUED AT 1044 AM CST MON DEC 9 2013
TEMPERATURES HAVE NOT RISEN ACROSS PORTIONS OF SOUTHEAST MINNESOTA
AND NORTHEAST IOWA THIS MORNING WHILE WINDS HAVE CONTINUED TO
INCREASE TO AROUND 20 TO 30 MPH. THIS HAS LEAD TO WIND CHILLS
DROPPING INTO THE 20 TO 30 DEGREES BELOW ZERO RANGE. WITH
TEMPERATURES NOT EXPECTED TO CLIMB MUCH AT ALL...WILL BE ISSUING A
WIND CHILL ADVISORY FOR PORTIONS OF SE MN/NE IA THROUGH THIS
AFTERNOON. HAVE ALSO ADDED A FEW COUNTIES IN NORTHWEST WISCONSIN
TO THE ADVISORY AND STARTED THE NORTH CENTRAL COUNTIES RIGHT NOW
AS WELL SINCE TEMPERATURES ARE GOING TO CONTINUE TO DROP THERE AS
WELL. EXACT COUNTIES/TIMING IS CURRENTLY BEING WORKED ON WITH
NEIGHBORING OFFICES AND THE ADVISORY SHOULD BE POSTED SHORTLY.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 352 AM CST MON DEC 9 2013
MAIN SHORT TERM CONCERNS ARE ON TEMPERATURES...WIND CHILLS AND
POTENTIAL FOR MORE SNOW LATER TONIGHT.
CURRENTLY AS OF 08Z...WATER VAPOR LOOP AND RAP 500MB HEIGHT ANALYSIS
SHOWED A HIGHLY AMPLIFIED RIDGE OVER THE EASTERN PACIFIC...A DEEP
TROUGH FROM CENTRAL CANADA INTO THE FOUR CORNERS...AND RIDGING OVER
THE SOUTHEASTERN U.S.. WITHIN THE DEEP TROUGH THERE WERE 3
SHORTWAVES OF NOTE. THE FIRST WAS OVER SOUTHEAST WISCONSIN WHICH
HELPED BRING THE SNOW TO THE AREA YESTERDAY INTO THE EARLY MORNING
HOURS. MOST OF THE SNOW HAS PUSHED OFF TO THE EAST AS SHOWN BY RADAR
IMAGERY...IN RESPONSE TO SUBSIDENCE AND ISENTROPIC DESCENT IN THE
WAKE OF THE SHORTWAVE. THE SECOND SHORTWAVE OF NOTE WAS OVER THE
DAKOTAS. ALTHOUGH THIS SHORTWAVE WAS ONLY PRODUCING SOME ALTOSTRATUS
AHEAD OF IT...DUE TO DRY AIR SEEN ON THE 00Z BIS SOUNDING...THERE
WAS PLENTY OF COLD AIR WITH IT. 850MB TEMPS ACCORDING TO THE RAP ARE
-25C ACROSS NORTH DAKOTA...OR 2 STANDARD DEVIATIONS BELOW NORMAL.
FINALLY...THE THIRD SHORTWAVE WAS COMING DOWN THE BACK SIDE OF THE
TROUGH THROUGH CENTRAL ALBERTA. IMPRESSIVE 140KT JET AT THE
TROPOPAUSE ACCOMPANYING THE SHORTWAVE. ALREADY SOME LIGHT SNOW
FALLING JUST AHEAD OF THE SHORTWAVE.
A LOT OF RAPID MOTION FORECAST OVER THE NEXT 24 HOURS IN THE UPPER
LEVEL PATTERN...MOSTLY A RESULT FROM THAT STRONG UPPER JET CORE
COMING THROUGH ALBERTA. FIRST OFF...THE SHORTWAVE TROUGH OVER NORTH
DAKOTA IS PROGGED BY MODELS TO SLIDE THROUGH THE FORECAST AREA THIS
AFTERNOON. WE MAY SEE SOME MID OR HIGH CLOUDS PASS THROUGH AHEAD OF
THE SHORTWAVE...BUT THE BULK OF THE CLOUD COVER IS GOING TO BE THE
CURRENT STRATUS AFFECTING THE AREA. ANTICIPATING AS THE SHORTWAVE
PASSES...THE DRY ARCTIC AIR SEEN ACROSS NORTH DAKOTA CURRENTLY WILL
CLEAR OUT THE STRATUS. THIS MAY HAPPEN PRETTY QUICK WITH CLEARING
ALREADY COMING INTO THE FORECAST AREA. IN ADDITION...THAT SAME
ARCTIC AIR IS EXPECTED TO CAUSE TEMPERATURES TO FALL AS 850MB TEMPS
PLUMMET FROM THE CURRENT -14 TO -18C READINGS TO -18 TO -22C BY 21Z.
WINDS LOOK TO CRANK UP TOO AS THAT SHORTWAVE AND ASSOCIATED COLD AIR
COME IN. THESE WINDS...WITH GUSTS UPWARDS OF 20 TO 30 MPH...ARE
LIKELY TO CAUSE SOME BLOWING AND DRIFTING OF THE RECENT SNOW. AS
TEMPERATURES FALL THIS AFTERNOON...WIND CHILLS WILL BECOME MORE OF
AN ISSUE. TAYLOR/CLARK COUNTIES LOOK TO DROP INTO ADVISORY RANGE
AROUND 22Z AND DO NOT GET OUT UNTIL 12Z TUESDAY...THUS HAVE GONE
AHEAD AND ISSUED AN ADVISORY FOR THEM.
THE COLD AIR TONIGHT DOES NOT LAST LONG. MODELS ARE IN GOOD
AGREEMENT SHOWING THE ALBERTA SHORTWAVE DIGGING INTO THE DAKOTAS
THIS EVENING...THEN MOVING INTO THE FORECAST AREA TOWARDS 12Z. AS
THIS SHORTWAVE APPROACHES...WARM ADVECTION ENSUES...WITH 850MB TEMPS
CLIMBING UP TO -13 TO -17C BY 09Z. ALL INDICATIONS ARE THAT THE
ISENTROPIC LIFT AND SOME MOISTURE ADVECTION WILL CAUSE A MID CLOUD
DECK TO SPREAD ACROSS THE FORECAST AREA. THESE CLOUDS AND THE WARM
ADVECTION SHOULD RESULT IN RISING TEMPS LATE THIS EVENING INTO THE
OVERNIGHT...HELPING TO BRING WIND CHILLS UP. ADDITIONALLY...THE BEST
JUXTAPOSITION OF LOW LEVEL SATURATION AND ISENTROPIC LIFT OCCURS
NORTH OF INTERSTATE 90. GIVEN THE ARCTIC AIRMASS IN PLACE PRIOR TO
THE SHORTWAVE ARRIVAL...LIKELY WILL NOT TAKE MUCH TO SNOW. QPF MAY
NOT AMOUNT TO MUCH WITH THE COLD AIRMASS...MAYBE A COUPLE HUNDREDTHS
TOPS...BUT ENOUGH FORCING TO WARRANT HIGH PRECIPITATION CHANCES.
.LONG TERM...(TUESDAY THROUGH SUNDAY)
ISSUED AT 352 AM CST MON DEC 9 2013
MAIN LONG TERM FORECAST CONCERNS ARE ON TEMPERATURES...AS WELL AS
THE OSCILLATING DIURNAL TRENDS WITH THEM...AND POTENTIAL FOR
PRECIPITATION THROUGHOUT.
SHORTWAVE TROUGH COMING INTO THE FORECAST AREA TONIGHT QUICKLY MOVES
THROUGH DURING THE TUESDAY MORNING HOURS. ANY SNOW LOOKS TO DEPART
OFF TO THE EAST PRETTY FAST IN THE MORNING...FOLLOWED BY CLEARING
AND BRISK WEST WINDS. THESE WINDS COULD RESULT IN MORE BLOWING
SNOW...ESPECIALLY IF WE CAN GET A FEW TENTHS OUT OF TONIGHT.
ADDITIONALLY...THE WINDS DRIVE IN A BRIEF SURGE OF ARCTIC AIR WITH
850MB TEMPS FALLING TO -16 TO -20C BY 18Z. 09.00Z
ECMWF/NAM/CANADIAN/GFS THEN ALL DEPICT YET ANOTHER SHORTWAVE TROUGH
DROPPING INTO THE DAKOTAS TUESDAY NIGHT. AHEAD OF THIS
FEATURE...INCREASING ISENTROPIC LIFT AND MID LEVEL FRONTOGENESIS
LOOKS TO DEVELOP A BAND OF SNOW. POSITION OF THIS BAND OF SNOW IS
PROBLEMATIC...WITH THE ECMWF/NAM FARTHER NORTH COMPARED TO THE
GFS/CANADIAN. CONSENSUS WOULD SUGGEST LOCATIONS SOUTH OF I-90 WOULD
STAND TO SEE THE BEST CHANCE OF SEEING SNOW...SO RAISED CHANCES
TOWARDS 60 IN THIS AREA. THE BAND DOES APPEAR TO BE QUICK MOVING...
SUCH THAT BY 12Z WEDNESDAY...ITS ALREADY SOUTHEAST OF THE AREA.
NONETHELESS...WITH SNOW TO WATER RATIOS APPROACH 20 TO 1...WE COULD
SQUEEZE OUT AN INCH OR SO OUT OF THIS BAND.
JUST LIKE IN THE WAKE OF THE EVERY SHORTWAVE TROUGH...ANOTHER SURGE
OF ARCTIC AIR IS PROGGED TO FLOW INTO THE AREA ON WEDNESDAY WHEN THE
TROUGH MOVES THROUGH. 850MB TEMPS DROP TO -20 TO -24C AT 18Z
WEDNESDAY. THUS...DESPITE THAT SKIES SHOULD CLEAR ON WEDNESDAY AS
THE TROUGH COMES IN...IT WILL BE TOUGH TO WARM UP MUCH. MOST
LOCATIONS ARE LIKELY TO NOT GET OUT OF THE SINGLE DIGITS ABOVE
ZERO...AND NORTH OF HIGHWAY 10 MAY NOT EVEN GET TO ZERO. WITH THE
COLD TEMPS AND A NORTHWEST BREEZE...WIND CHILLS ARE YET AGAIN A
FACTOR WITH ANOTHER ADVISORY LIKELY NEEDED. NORTH OF HIGHWAY 10
APPEARS TO BE THE MOST LIKELY AREA FOR AN ADVISORY...STARTING LATE
TUESDAY NIGHT AND RUNNING THROUGH WEDNESDAY NIGHT. WEDNESDAY NIGHT
IS INTERESTING TOO. ALL MODELS ARE SUGGESTING RISING 500MB HEIGHTS
ACROSS THE CENTRAL PART OF THE COUNTRY. WARM ADVECTION ASSOCIATED
WITH THESE RISING HEIGHTS SHOULD CAUSE TEMPERATURES TO RISE...AFTER
A RAPID DROP OFF IN THE EVENING ASSOCIATED WITH A SURFACE RIDGE
PASSAGE. THERE MAY EVEN BE SOME SNOW THAT TRIES TO GET GOING NORTH
OF I-94...AS SUGGESTED BY THE ECMWF/CANADIAN AND HAVE INCLUDED 20
PERCENT CHANCES FOR THIS. THESE CHANCES PERSIST INTO THURSDAY. MUCH
WARMER 850MB TEMPS ON THURSDAY...ON THE ORDER OF -2 TO -8C BY
00Z...WILL RESULT IN HIGHS 15-20 DEGREES WARMER COMPARED TO
WEDNESDAY.
FROM THURSDAY NIGHT THROUGH SUNDAY...09.00Z ECMWF/GFS/CANADIAN
SUGGEST A NORTHWEST FLOW PATTERN IN THE MEAN...STRETCHING FROM
BRITISH COLUMBIA INTO THE GREAT LAKES. AT THE MOMENT THURSDAY NIGHT
LOOKS DRY. AS WE HEAD INTO FRIDAY AND ESPECIALLY FRIDAY
NIGHT...THERE ARE SUGGESTIONS A SOUTHERN STREAM SHORTWAVE TROUGH
COMING OUT OF THE CENTRAL PLAINS AND HEADING INTO THE OHIO VALLEY
COULD SPREAD SOME LIGHT SNOW INTO THE FORECAST AREA. THE CANADIAN IS
THE FARTHEST NORTHWEST AND DID HONOR THE SOLUTION WITH A 20 PERCENT
CHANCE. HOWEVER...THE 09.00Z GFS/ECMWF SUGGEST IT COULD STAY TO THE
SOUTHEAST...THUS SOMETHING TO MONITOR. HEADING INTO THE WEEKEND...
THE ECMWF/GFS SUGGEST A POTENT UPPER TROUGH WILL BE DROPPING SOUTH
INTO MANITOBA AND ONTARIO. THE ECMWF IS VERY AGGRESSIVE DIGGING IT
INTO WISCONSIN ON SUNDAY. FOR NOW STAYED WITH THE CONSENSUS WHICH
YIELDS A GENERALLY DRY SOLUTION WITH TEMPERATURES HOVERING SLIGHTLY
BELOW NORMAL. HOWEVER...SHOULD THE 00Z ECMWF BE CORRECT...
TEMPERATURES MAY NEED SIGNIFICANT LOWERING FOR SUNDAY.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z TUESDAY MORNING)
ISSUED AT 542 AM CST MON DEC 9 2013
VFR TO MVFR CONDITIONS ARE EXPECTED AT THE TAF SITES TODAY. GUSTY
WEST WINDS OF 14 TO 18 KTS WITH GUSTS AROUND 24KTS WILL LEAD TO
SOME PATCHY BLOWING SNOW...POSSIBLY REDUCING VISIBILITIES TO
AROUND 5SM AT TIMES. SOUTH/SOUTHWEST WINDS WILL INCREASE LATE
TONIGHT AHEAD OF A WEAK SYSTEM APPROACHING FROM THE NORTHERN
PLAINS. LOOK FOR WINDS TO INCREASE INTO THE 14 TO 18 KT RANGE
AGAIN WITH GUSTS AROUND 25 KTS POSSIBLE. SOME PATCHY BLOWING SNOW
MAY OCCUR AGAIN LATE TONIGHT AS THE WINDS INCREASE. LIGHT SNOW OR
FLURRIES WILL MOVE ACROSS THE TAF SITES MAINLY AFTER 10Z TONIGHT.
A BRIEF PERIOD OF MVFR OR POSSIBLY IFR CONDITIONS MAY OCCUR AS THE
SNOW MOVES THROUGH.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
WI...WIND CHILL ADVISORY FROM 4 PM THIS AFTERNOON TO 6 AM CST TUESDAY
FOR WIZ017-029.
MN...NONE.
IA...NONE.
&&
$$
UPDATE...HALBACH
SHORT TERM...AJ
LONG TERM...AJ
AVIATION...WETENKAMP
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
542 AM CST MON DEC 9 2013
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 352 AM CST MON DEC 9 2013
MAIN SHORT TERM CONCERNS ARE ON TEMPERATURES...WIND CHILLS AND
POTENTIAL FOR MORE SNOW LATER TONIGHT.
CURRENTLY AS OF 08Z...WATER VAPOR LOOP AND RAP 500MB HEIGHT ANALYSIS
SHOWED A HIGHLY AMPLIFIED RIDGE OVER THE EASTERN PACIFIC...A DEEP
TROUGH FROM CENTRAL CANADA INTO THE FOUR CORNERS...AND RIDGING OVER
THE SOUTHEASTERN U.S.. WITHIN THE DEEP TROUGH THERE WERE 3
SHORTWAVES OF NOTE. THE FIRST WAS OVER SOUTHEAST WISCONSIN WHICH
HELPED BRING THE SNOW TO THE AREA YESTERDAY INTO THE EARLY MORNING
HOURS. MOST OF THE SNOW HAS PUSHED OFF TO THE EAST AS SHOWN BY RADAR
IMAGERY...IN RESPONSE TO SUBSIDENCE AND ISENTROPIC DESCENT IN THE
WAKE OF THE SHORTWAVE. THE SECOND SHORTWAVE OF NOTE WAS OVER THE
DAKOTAS. ALTHOUGH THIS SHORTWAVE WAS ONLY PRODUCING SOME ALTOSTRATUS
AHEAD OF IT...DUE TO DRY AIR SEEN ON THE 00Z BIS SOUNDING...THERE
WAS PLENTY OF COLD AIR WITH IT. 850MB TEMPS ACCORDING TO THE RAP ARE
-25C ACROSS NORTH DAKOTA...OR 2 STANDARD DEVIATIONS BELOW NORMAL.
FINALLY...THE THIRD SHORTWAVE WAS COMING DOWN THE BACK SIDE OF THE
TROUGH THROUGH CENTRAL ALBERTA. IMPRESSIVE 140KT JET AT THE
TROPOPAUSE ACCOMPANYING THE SHORTWAVE. ALREADY SOME LIGHT SNOW
FALLING JUST AHEAD OF THE SHORTWAVE.
A LOT OF RAPID MOTION FORECAST OVER THE NEXT 24 HOURS IN THE UPPER
LEVEL PATTERN...MOSTLY A RESULT FROM THAT STRONG UPPER JET CORE
COMING THROUGH ALBERTA. FIRST OFF...THE SHORTWAVE TROUGH OVER NORTH
DAKOTA IS PROGGED BY MODELS TO SLIDE THROUGH THE FORECAST AREA THIS
AFTERNOON. WE MAY SEE SOME MID OR HIGH CLOUDS PASS THROUGH AHEAD OF
THE SHORTWAVE...BUT THE BULK OF THE CLOUD COVER IS GOING TO BE THE
CURRENT STRATUS AFFECTING THE AREA. ANTICIPATING AS THE SHORTWAVE
PASSES...THE DRY ARCTIC AIR SEEN ACROSS NORTH DAKOTA CURRENTLY WILL
CLEAR OUT THE STRATUS. THIS MAY HAPPEN PRETTY QUICK WITH CLEARING
ALREADY COMING INTO THE FORECAST AREA. IN ADDITION...THAT SAME
ARCTIC AIR IS EXPECTED TO CAUSE TEMPERATURES TO FALL AS 850MB TEMPS
PLUMMET FROM THE CURRENT -14 TO -18C READINGS TO -18 TO -22C BY 21Z.
WINDS LOOK TO CRANK UP TOO AS THAT SHORTWAVE AND ASSOCIATED COLD AIR
COME IN. THESE WINDS...WITH GUSTS UPWARDS OF 20 TO 30 MPH...ARE
LIKELY TO CAUSE SOME BLOWING AND DRIFTING OF THE RECENT SNOW. AS
TEMPERATURES FALL THIS AFTERNOON...WIND CHILLS WILL BECOME MORE OF
AN ISSUE. TAYLOR/CLARK COUNTIES LOOK TO DROP INTO ADVISORY RANGE
AROUND 22Z AND DO NOT GET OUT UNTIL 12Z TUESDAY...THUS HAVE GONE
AHEAD AND ISSUED AN ADVISORY FOR THEM.
THE COLD AIR TONIGHT DOES NOT LAST LONG. MODELS ARE IN GOOD
AGREEMENT SHOWING THE ALBERTA SHORTWAVE DIGGING INTO THE DAKOTAS
THIS EVENING...THEN MOVING INTO THE FORECAST AREA TOWARDS 12Z. AS
THIS SHORTWAVE APPROACHES...WARM ADVECTION ENSUES...WITH 850MB TEMPS
CLIMBING UP TO -13 TO -17C BY 09Z. ALL INDICATIONS ARE THAT THE
ISENTROPIC LIFT AND SOME MOISTURE ADVECTION WILL CAUSE A MID CLOUD
DECK TO SPREAD ACROSS THE FORECAST AREA. THESE CLOUDS AND THE WARM
ADVECTION SHOULD RESULT IN RISING TEMPS LATE THIS EVENING INTO THE
OVERNIGHT...HELPING TO BRING WIND CHILLS UP. ADDITIONALLY...THE BEST
JUXTAPOSITION OF LOW LEVEL SATURATION AND ISENTROPIC LIFT OCCURS
NORTH OF INTERSTATE 90. GIVEN THE ARCTIC AIRMASS IN PLACE PRIOR TO
THE SHORTWAVE ARRIVAL...LIKELY WILL NOT TAKE MUCH TO SNOW. QPF MAY
NOT AMOUNT TO MUCH WITH THE COLD AIRMASS...MAYBE A COUPLE HUNDREDTHS
TOPS...BUT ENOUGH FORCING TO WARRANT HIGH PRECIPITATION CHANCES.
.LONG TERM...(TUESDAY THROUGH SUNDAY)
ISSUED AT 352 AM CST MON DEC 9 2013
MAIN LONG TERM FORECAST CONCERNS ARE ON TEMPERATURES...AS WELL AS
THE OSCILLATING DIURNAL TRENDS WITH THEM...AND POTENTIAL FOR
PRECIPITATION THROUGHOUT.
SHORTWAVE TROUGH COMING INTO THE FORECAST AREA TONIGHT QUICKLY MOVES
THROUGH DURING THE TUESDAY MORNING HOURS. ANY SNOW LOOKS TO DEPART
OFF TO THE EAST PRETTY FAST IN THE MORNING...FOLLOWED BY CLEARING
AND BRISK WEST WINDS. THESE WINDS COULD RESULT IN MORE BLOWING
SNOW...ESPECIALLY IF WE CAN GET A FEW TENTHS OUT OF TONIGHT.
ADDITIONALLY...THE WINDS DRIVE IN A BRIEF SURGE OF ARCTIC AIR WITH
850MB TEMPS FALLING TO -16 TO -20C BY 18Z. 09.00Z
ECMWF/NAM/CANADIAN/GFS THEN ALL DEPICT YET ANOTHER SHORTWAVE TROUGH
DROPPING INTO THE DAKOTAS TUESDAY NIGHT. AHEAD OF THIS
FEATURE...INCREASING ISENTROPIC LIFT AND MID LEVEL FRONTOGENESIS
LOOKS TO DEVELOP A BAND OF SNOW. POSITION OF THIS BAND OF SNOW IS
PROBLEMATIC...WITH THE ECMWF/NAM FARTHER NORTH COMPARED TO THE
GFS/CANADIAN. CONSENSUS WOULD SUGGEST LOCATIONS SOUTH OF I-90 WOULD
STAND TO SEE THE BEST CHANCE OF SEEING SNOW...SO RAISED CHANCES
TOWARDS 60 IN THIS AREA. THE BAND DOES APPEAR TO BE QUICK MOVING...
SUCH THAT BY 12Z WEDNESDAY...ITS ALREADY SOUTHEAST OF THE AREA.
NONETHELESS...WITH SNOW TO WATER RATIOS APPROACH 20 TO 1...WE COULD
SQUEEZE OUT AN INCH OR SO OUT OF THIS BAND.
JUST LIKE IN THE WAKE OF THE EVERY SHORTWAVE TROUGH...ANOTHER SURGE
OF ARCTIC AIR IS PROGGED TO FLOW INTO THE AREA ON WEDNESDAY WHEN THE
TROUGH MOVES THROUGH. 850MB TEMPS DROP TO -20 TO -24C AT 18Z
WEDNESDAY. THUS...DESPITE THAT SKIES SHOULD CLEAR ON WEDNESDAY AS
THE TROUGH COMES IN...IT WILL BE TOUGH TO WARM UP MUCH. MOST
LOCATIONS ARE LIKELY TO NOT GET OUT OF THE SINGLE DIGITS ABOVE
ZERO...AND NORTH OF HIGHWAY 10 MAY NOT EVEN GET TO ZERO. WITH THE
COLD TEMPS AND A NORTHWEST BREEZE...WIND CHILLS ARE YET AGAIN A
FACTOR WITH ANOTHER ADVISORY LIKELY NEEDED. NORTH OF HIGHWAY 10
APPEARS TO BE THE MOST LIKELY AREA FOR AN ADVISORY...STARTING LATE
TUESDAY NIGHT AND RUNNING THROUGH WEDNESDAY NIGHT. WEDNESDAY NIGHT
IS INTERESTING TOO. ALL MODELS ARE SUGGESTING RISING 500MB HEIGHTS
ACROSS THE CENTRAL PART OF THE COUNTRY. WARM ADVECTION ASSOCIATED
WITH THESE RISING HEIGHTS SHOULD CAUSE TEMPERATURES TO RISE...AFTER
A RAPID DROP OFF IN THE EVENING ASSOCIATED WITH A SURFACE RIDGE
PASSAGE. THERE MAY EVEN BE SOME SNOW THAT TRIES TO GET GOING NORTH
OF I-94...AS SUGGESTED BY THE ECMWF/CANADIAN AND HAVE INCLUDED 20
PERCENT CHANCES FOR THIS. THESE CHANCES PERSIST INTO THURSDAY. MUCH
WARMER 850MB TEMPS ON THURSDAY...ON THE ORDER OF -2 TO -8C BY
00Z...WILL RESULT IN HIGHS 15-20 DEGREES WARMER COMPARED TO
WEDNESDAY.
FROM THURSDAY NIGHT THROUGH SUNDAY...09.00Z ECMWF/GFS/CANADIAN
SUGGEST A NORTHWEST FLOW PATTERN IN THE MEAN...STRETCHING FROM
BRITISH COLUMBIA INTO THE GREAT LAKES. AT THE MOMENT THURSDAY NIGHT
LOOKS DRY. AS WE HEAD INTO FRIDAY AND ESPECIALLY FRIDAY
NIGHT...THERE ARE SUGGESTIONS A SOUTHERN STREAM SHORTWAVE TROUGH
COMING OUT OF THE CENTRAL PLAINS AND HEADING INTO THE OHIO VALLEY
COULD SPREAD SOME LIGHT SNOW INTO THE FORECAST AREA. THE CANADIAN IS
THE FARTHEST NORTHWEST AND DID HONOR THE SOLUTION WITH A 20 PERCENT
CHANCE. HOWEVER...THE 09.00Z GFS/ECMWF SUGGEST IT COULD STAY TO THE
SOUTHEAST...THUS SOMETHING TO MONITOR. HEADING INTO THE WEEKEND...
THE ECMWF/GFS SUGGEST A POTENT UPPER TROUGH WILL BE DROPPING SOUTH
INTO MANITOBA AND ONTARIO. THE ECMWF IS VERY AGGRESSIVE DIGGING IT
INTO WISCONSIN ON SUNDAY. FOR NOW STAYED WITH THE CONSENSUS WHICH
YIELDS A GENERALLY DRY SOLUTION WITH TEMPERATURES HOVERING SLIGHTLY
BELOW NORMAL. HOWEVER...SHOULD THE 00Z ECMWF BE CORRECT...
TEMPERATURES MAY NEED SIGNIFICANT LOWERING FOR SUNDAY.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z TUESDAY MORNING)
ISSUED AT 542 AM CST MON DEC 9 2013
VFR TO MVFR CONDITIONS ARE EXPECTED AT THE TAF SITES TODAY. GUSTY
WEST WINDS OF 14 TO 18 KTS WITH GUSTS AROUND 24KTS WILL LEAD TO
SOME PATCHY BLOWING SNOW...POSSIBLY REDUCING VISIBILITIES TO
AROUND 5SM AT TIMES. SOUTH/SOUTHWEST WINDS WILL INCREASE LATE
TONIGHT AHEAD OF A WEAK SYSTEM APPROACHING FROM THE NORTHERN
PLAINS. LOOK FOR WINDS TO INCREASE INTO THE 14 TO 18 KT RANGE
AGAIN WITH GUSTS AROUND 25 KTS POSSIBLE. SOME PATCHY BLOWING SNOW
MAY OCCUR AGAIN LATE TONIGHT AS THE WINDS INCREASE. LIGHT SNOW OR
FLURRIES WILL MOVE ACROSS THE TAF SITES MAINLY AFTER 10Z TONIGHT.
A BRIEF PERIOD OF MVFR OR POSSIBLY IFR CONDITIONS MAY OCCUR AS THE
SNOW MOVES THROUGH.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
WI...WIND CHILL ADVISORY FROM 4 PM THIS AFTERNOON TO 6 AM CST TUESDAY
FOR WIZ017-029.
MN...NONE.
IA...NONE.
&&
$$
SHORT TERM...AJ
LONG TERM...AJ
AVIATION...WETENKAMP
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
352 AM CST MON DEC 9 2013
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 352 AM CST MON DEC 9 2013
MAIN SHORT TERM CONCERNS ARE ON TEMPERATURES...WIND CHILLS AND
POTENTIAL FOR MORE SNOW LATER TONIGHT.
CURRENTLY AS OF 08Z...WATER VAPOR LOOP AND RAP 500MB HEIGHT ANALYSIS
SHOWED A HIGHLY AMPLIFIED RIDGE OVER THE EASTERN PACIFIC...A DEEP
TROUGH FROM CENTRAL CANADA INTO THE FOUR CORNERS...AND RIDGING OVER
THE SOUTHEASTERN U.S.. WITHIN THE DEEP TROUGH THERE WERE 3
SHORTWAVES OF NOTE. THE FIRST WAS OVER SOUTHEAST WISCONSIN WHICH
HELPED BRING THE SNOW TO THE AREA YESTERDAY INTO THE EARLY MORNING
HOURS. MOST OF THE SNOW HAS PUSHED OFF TO THE EAST AS SHOWN BY RADAR
IMAGERY...IN RESPONSE TO SUBSIDENCE AND ISENTROPIC DESCENT IN THE
WAKE OF THE SHORTWAVE. THE SECOND SHORTWAVE OF NOTE WAS OVER THE
DAKOTAS. ALTHOUGH THIS SHORTWAVE WAS ONLY PRODUCING SOME ALTOSTRATUS
AHEAD OF IT...DUE TO DRY AIR SEEN ON THE 00Z BIS SOUNDING...THERE
WAS PLENTY OF COLD AIR WITH IT. 850MB TEMPS ACCORDING TO THE RAP ARE
-25C ACROSS NORTH DAKOTA...OR 2 STANDARD DEVIATIONS BELOW NORMAL.
FINALLY...THE THIRD SHORTWAVE WAS COMING DOWN THE BACK SIDE OF THE
TROUGH THROUGH CENTRAL ALBERTA. IMPRESSIVE 140KT JET AT THE
TROPOPAUSE ACCOMPANYING THE SHORTWAVE. ALREADY SOME LIGHT SNOW
FALLING JUST AHEAD OF THE SHORTWAVE.
A LOT OF RAPID MOTION FORECAST OVER THE NEXT 24 HOURS IN THE UPPER
LEVEL PATTERN...MOSTLY A RESULT FROM THAT STRONG UPPER JET CORE
COMING THROUGH ALBERTA. FIRST OFF...THE SHORTWAVE TROUGH OVER NORTH
DAKOTA IS PROGGED BY MODELS TO SLIDE THROUGH THE FORECAST AREA THIS
AFTERNOON. WE MAY SEE SOME MID OR HIGH CLOUDS PASS THROUGH AHEAD OF
THE SHORTWAVE...BUT THE BULK OF THE CLOUD COVER IS GOING TO BE THE
CURRENT STRATUS AFFECTING THE AREA. ANTICIPATING AS THE SHORTWAVE
PASSES...THE DRY ARCTIC AIR SEEN ACROSS NORTH DAKOTA CURRENTLY WILL
CLEAR OUT THE STRATUS. THIS MAY HAPPEN PRETTY QUICK WITH CLEARING
ALREADY COMING INTO THE FORECAST AREA. IN ADDITION...THAT SAME
ARCTIC AIR IS EXPECTED TO CAUSE TEMPERATURES TO FALL AS 850MB TEMPS
PLUMMET FROM THE CURRENT -14 TO -18C READINGS TO -18 TO -22C BY 21Z.
WINDS LOOK TO CRANK UP TOO AS THAT SHORTWAVE AND ASSOCIATED COLD AIR
COME IN. THESE WINDS...WITH GUSTS UPWARDS OF 20 TO 30 MPH...ARE
LIKELY TO CAUSE SOME BLOWING AND DRIFTING OF THE RECENT SNOW. AS
TEMPERATURES FALL THIS AFTERNOON...WIND CHILLS WILL BECOME MORE OF
AN ISSUE. TAYLOR/CLARK COUNTIES LOOK TO DROP INTO ADVISORY RANGE
AROUND 22Z AND DO NOT GET OUT UNTIL 12Z TUESDAY...THUS HAVE GONE
AHEAD AND ISSUED AN ADVISORY FOR THEM.
THE COLD AIR TONIGHT DOES NOT LAST LONG. MODELS ARE IN GOOD
AGREEMENT SHOWING THE ALBERTA SHORTWAVE DIGGING INTO THE DAKOTAS
THIS EVENING...THEN MOVING INTO THE FORECAST AREA TOWARDS 12Z. AS
THIS SHORTWAVE APPROACHES...WARM ADVECTION ENSUES...WITH 850MB TEMPS
CLIMBING UP TO -13 TO -17C BY 09Z. ALL INDICATIONS ARE THAT THE
ISENTROPIC LIFT AND SOME MOISTURE ADVECTION WILL CAUSE A MID CLOUD
DECK TO SPREAD ACROSS THE FORECAST AREA. THESE CLOUDS AND THE WARM
ADVECTION SHOULD RESULT IN RISING TEMPS LATE THIS EVENING INTO THE
OVERNIGHT...HELPING TO BRING WIND CHILLS UP. ADDITIONALLY...THE BEST
JUXTAPOSITION OF LOW LEVEL SATURATION AND ISENTROPIC LIFT OCCURS
NORTH OF INTERSTATE 90. GIVEN THE ARCTIC AIRMASS IN PLACE PRIOR TO
THE SHORTWAVE ARRIVAL...LIKELY WILL NOT TAKE MUCH TO SNOW. QPF MAY
NOT AMOUNT TO MUCH WITH THE COLD AIRMASS...MAYBE A COUPLE HUNDREDTHS
TOPS...BUT ENOUGH FORCING TO WARRANT HIGH PRECIPITATION CHANCES.
.LONG TERM...(TUESDAY THROUGH SUNDAY)
ISSUED AT 352 AM CST MON DEC 9 2013
MAIN LONG TERM FORECAST CONCERNS ARE ON TEMPERATURES...AS WELL AS
THE OSCILLATING DIURNAL TRENDS WITH THEM...AND POTENTIAL FOR
PRECIPITATION THROUGHOUT.
SHORTWAVE TROUGH COMING INTO THE FORECAST AREA TONIGHT QUICKLY MOVES
THROUGH DURING THE TUESDAY MORNING HOURS. ANY SNOW LOOKS TO DEPART
OFF TO THE EAST PRETTY FAST IN THE MORNING...FOLLOWED BY CLEARING
AND BRISK WEST WINDS. THESE WINDS COULD RESULT IN MORE BLOWING
SNOW...ESPECIALLY IF WE CAN GET A FEW TENTHS OUT OF TONIGHT.
ADDITIONALLY...THE WINDS DRIVE IN A BRIEF SURGE OF ARCTIC AIR WITH
850MB TEMPS FALLING TO -16 TO -20C BY 18Z. 09.00Z
ECMWF/NAM/CANADIAN/GFS THEN ALL DEPICT YET ANOTHER SHORTWAVE TROUGH
DROPPING INTO THE DAKOTAS TUESDAY NIGHT. AHEAD OF THIS
FEATURE...INCREASING ISENTROPIC LIFT AND MID LEVEL FRONTOGENESIS
LOOKS TO DEVELOP A BAND OF SNOW. POSITION OF THIS BAND OF SNOW IS
PROBLEMATIC...WITH THE ECMWF/NAM FARTHER NORTH COMPARED TO THE
GFS/CANADIAN. CONSENSUS WOULD SUGGEST LOCATIONS SOUTH OF I-90 WOULD
STAND TO SEE THE BEST CHANCE OF SEEING SNOW...SO RAISED CHANCES
TOWARDS 60 IN THIS AREA. THE BAND DOES APPEAR TO BE QUICK MOVING...
SUCH THAT BY 12Z WEDNESDAY...ITS ALREADY SOUTHEAST OF THE AREA.
NONETHELESS...WITH SNOW TO WATER RATIOS APPROACH 20 TO 1...WE COULD
SQUEEZE OUT AN INCH OR SO OUT OF THIS BAND.
JUST LIKE IN THE WAKE OF THE EVERY SHORTWAVE TROUGH...ANOTHER SURGE
OF ARCTIC AIR IS PROGGED TO FLOW INTO THE AREA ON WEDNESDAY WHEN THE
TROUGH MOVES THROUGH. 850MB TEMPS DROP TO -20 TO -24C AT 18Z
WEDNESDAY. THUS...DESPITE THAT SKIES SHOULD CLEAR ON WEDNESDAY AS
THE TROUGH COMES IN...IT WILL BE TOUGH TO WARM UP MUCH. MOST
LOCATIONS ARE LIKELY TO NOT GET OUT OF THE SINGLE DIGITS ABOVE
ZERO...AND NORTH OF HIGHWAY 10 MAY NOT EVEN GET TO ZERO. WITH THE
COLD TEMPS AND A NORTHWEST BREEZE...WIND CHILLS ARE YET AGAIN A
FACTOR WITH ANOTHER ADVISORY LIKELY NEEDED. NORTH OF HIGHWAY 10
APPEARS TO BE THE MOST LIKELY AREA FOR AN ADVISORY...STARTING LATE
TUESDAY NIGHT AND RUNNING THROUGH WEDNESDAY NIGHT. WEDNESDAY NIGHT
IS INTERESTING TOO. ALL MODELS ARE SUGGESTING RISING 500MB HEIGHTS
ACROSS THE CENTRAL PART OF THE COUNTRY. WARM ADVECTION ASSOCIATED
WITH THESE RISING HEIGHTS SHOULD CAUSE TEMPERATURES TO RISE...AFTER
A RAPID DROP OFF IN THE EVENING ASSOCIATED WITH A SURFACE RIDGE
PASSAGE. THERE MAY EVEN BE SOME SNOW THAT TRIES TO GET GOING NORTH
OF I-94...AS SUGGESTED BY THE ECMWF/CANADIAN AND HAVE INCLUDED 20
PERCENT CHANCES FOR THIS. THESE CHANCES PERSIST INTO THURSDAY. MUCH
WARMER 850MB TEMPS ON THURSDAY...ON THE ORDER OF -2 TO -8C BY
00Z...WILL RESULT IN HIGHS 15-20 DEGREES WARMER COMPARED TO
WEDNESDAY.
FROM THURSDAY NIGHT THROUGH SUNDAY...09.00Z ECMWF/GFS/CANADIAN
SUGGEST A NORTHWEST FLOW PATTERN IN THE MEAN...STRETCHING FROM
BRITISH COLUMBIA INTO THE GREAT LAKES. AT THE MOMENT THURSDAY NIGHT
LOOKS DRY. AS WE HEAD INTO FRIDAY AND ESPECIALLY FRIDAY
NIGHT...THERE ARE SUGGESTIONS A SOUTHERN STREAM SHORTWAVE TROUGH
COMING OUT OF THE CENTRAL PLAINS AND HEADING INTO THE OHIO VALLEY
COULD SPREAD SOME LIGHT SNOW INTO THE FORECAST AREA. THE CANADIAN IS
THE FARTHEST NORTHWEST AND DID HONOR THE SOLUTION WITH A 20 PERCENT
CHANCE. HOWEVER...THE 09.00Z GFS/ECMWF SUGGEST IT COULD STAY TO THE
SOUTHEAST...THUS SOMETHING TO MONITOR. HEADING INTO THE WEEKEND...
THE ECMWF/GFS SUGGEST A POTENT UPPER TROUGH WILL BE DROPPING SOUTH
INTO MANITOBA AND ONTARIO. THE ECMWF IS VERY AGGRESSIVE DIGGING IT
INTO WISCONSIN ON SUNDAY. FOR NOW STAYED WITH THE CONSENSUS WHICH
YIELDS A GENERALLY DRY SOLUTION WITH TEMPERATURES HOVERING SLIGHTLY
BELOW NORMAL. HOWEVER...SHOULD THE 00Z ECMWF BE CORRECT...
TEMPERATURES MAY NEED SIGNIFICANT LOWERING FOR SUNDAY.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z MONDAY NIGHT)
ISSUED AT 1100 PM CST SUN DEC 8 2013
SNOW WILL BE EXITING EAST OVER THE NEXT FEW HOURS AS THE RESPONSIBLE
UPPER LEVEL SHORTWAVE HEADS TOWARD THE EASTERN GREAT LAKES. WINDS
WILL PICK UP BY MONDAY MORNING...BECOMING GUSTY FROM THE WEST. THIS
COULD RESULT IN A PERIOD OF DRIFTING/BLOWING OF THE FRESHLY FALLEN
SNOW AT KRST. WITH SNOW AMOUNTS RELATIVELY SMALL THOUGH...IMPACT ON
THE VSBY WILL LIKELY BE MINIMAL.
CIGS WILL BE PROBLEMATIC AS A MIX OF MVFR/VFR CONTINUES PER LATEST
SFC OBS...AND PINPOINTING A REASON FOR THE VARIABILITY IS DIFFICULT.
WILL CONTINUE TO SIDE TOWARD MORE MVFR FOR THE OVERNIGHT
HOURS...CLIMBING TO VFR...AND THEN BREAKING OUT INTO SCT SKIES FOR
MONDAY AFTERNOON. CLOUDS WILL QUICKLY RETURN MONDAY NIGHT AS ANOTHER
SHORTWAVE TROUGH SPINS ACROSS THE REGION. COULD SEE A PERIOD OF MVFR
OVERNIGHT WITH SOME -SN.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
WI...WIND CHILL ADVISORY FROM 4 PM THIS AFTERNOON TO 6 AM CST TUESDAY
FOR WIZ017-029.
MN...NONE.
IA...NONE.
&&
$$
SHORT TERM...AJ
LONG TERM...AJ
AVIATION.....RIECK
AREA FORECAST DISCUSSION
NWS GREEN BAY WI
1144 PM CST SUN DEC 8 2013
UPDATED AVIATION PORTION FOR 06Z TAF ISSUANCE
.UPDATE...
ISSUED AT 856 PM CST SUN DEC 8 2013
CANCELLED WINTER WX ADVISORY FOR NORTHWEST PORTION OF FORECAST
AREA AS HAVE HAD GENERALLY LESS THAN AN INCH UP THERE WITH VSBYS
REMAINING IN THE 3 TO 5 MILES RANGE. EXPECT TO SEE AN INCH OR LESS
ADDITONAL ACCUMULATION OVERNIGHT THERE.
AREA OF LIGHT SNOW OVER FOX VALLEY LATE THIS EVENING ASSOCIATED
WITH SHORTWAVE DISTURBANCE MOVING ACROSS SOUTHEAST WISCONSIN.
VSBYS GENERALLY AROUND 2 MILES WITH SNOWFALL RATES A BIT HIGHER
ALONG THE LAKESHORE AS LAKE ENHANCEMENT CONTINUES THERE. VSBYS
FROM KEWAUNEE TO SOUTHEAST BROWN COUNTY...TO EAST OF OSHKOSH
BEWTEEN 1 AND 2 MILES. BACK/WESTERN EDGE OF THIS AREA OF LIGHT
SNOW APPROACHING THE FOX VALLEY THUS EXPECT LIGHT SNOW TO TAPER
OFF FROM SOUTHWEST TO NORTHEAST OVER THE NEXT FEW HOURS...EXCEPT
FOR THE LAKESHORE COUNTIES.
UPSTREAM SHORTWAVE MOVING ACROSS IOWA CONTINUED TO LOOK UNIMPRESSIVE
AS IT APPROACHES THE FORECAST AREA. DO NOT FEEL THIS FEATURE WILL
BE ABLE TO DO MUCH TO FURTHER ENHANCE LIGHT SNOW OVER THE FORECAST
AREA AFTER MIDNIGHT. LATEST RUC...NAM AND HRRR ARE ALL SUGGEST
WEAK LIFT AND VERY MINIMAL QPF AMOUNTS. WILL KEEP ADVISORY GOING
FOR NOW GIVEN LIGHT SNOW STILL FALLING OVER MUCH OF THE FORECAST
AREA. MAY TRIM ADDITIONAL COUNTIES TO THE WEST OF THE FOX VALLEY
FROM ADVISORY BEFORE MIDNIGHT IF RADAR RETURNS AND OBSERVED VSBYS
REMAIN LACKLUSTER.
HIGHEST SNOWFALL AMOUNTS HAVE GENERALLY BEEN AROUND 3 INCHES ALONG
THE LAKESHORE FROM MANITOWOC TO DOOR COUNTY. ABOUT 2 INCHES AT
NWS GREEN BAY AS OF 845 PM. JUST RECEIVED A REPORT OF 1.8 INCHES
SO FAR IN EAST GREEN BAY.
UPDATE
ISSUED AT 644 PM CST SUN DEC 8 2013
SYSTEM AFFECTING THE FORECAST AREA HAS BEEN RATHER DISORGANIZED
AND DISJOINTED THUS FAR. SO FAR...SNOWFALL AMOUNTS HAVE BEEN
AROUND AN INCH OR SO THROUGH 6 PM. HOWEVER...WATER VAPOR IMAGERY
SHOWS SOMEWHAT MORE ROBUST SHORTWAVE DISTURBANCE ENTERING
SOUTHWEST WISCONSIN. THIS FEATURE HAS HELPED TO CREATE A SOMEWHAT
MORE SOLID AND ORGANIZED AREA OF LIGHT SNOW ACROSS SOUTHEAST
WISCONSIN WITH VSBYS GENERALLY BETWEEN ABOUT 1 AND 2 MILES. THIS
AREA OF LIGHT SNOW CONTINUES TO DRIFT NORTHEAST AND WILL LIKELY CLIP
THE SOUTHEAST PORTION OF THE FOX VALLEY GENERALLY SOUTH OF A LINE
FROM OSH TO KEWAUNEE OVER THE NEXT FEW HOURS.
FURTHER AS ANTICIPATED...AN AREA OF LAKE ENHANCED SNOW CONTINUES
TO DEVELOP OVER CENTRAL LAKE MICHIGAN AND IS DRIFTING NORTHWEST.
RADAR REFLECTIVITIES HAVE BEEN GRADUALLY INCREASING AND EXPNADING
IN AREA COVERAGE OVER THE LAST HOUR. APPEARS ACTIVITY AHEAD OF
APPROACHING SHORTWAVE ENTERING SOUTHWEST WISCONSIN CONTRIBUTING TO
LES ENHANCEMENT OVER CENTRAL LAKE MICHIGAN VIA SEEDER-FEEDER
MECHANISM.
THUS...EXPECT TO SEE SOMEWHAT HIGHER SNOWFALL RATES ACROSS THE
FOX VALLEY THIS EVENING IN ASSOCIATION WITH SHORTWAVE MOVING
ACROSS SOUTHEAST WISCONSIN AND LAKE ENHANCEMENT OFF LAKE MICHIGAN.
COULD SEE ANOTHER INCH OR PERHAPS TWO MY MIDNIGHT ESPECIALLY
SOUTHEAST OFF A LINE FROM STURGEON BAY TO GREEN BAY TO OSHKOSH.
LOOKING FURTHER UPSTREAM...PRIMARY SHORTWAVE DISTURBANCE NOW
ENTERING NORTHWEST IOWA. THIS FEATURE IS ALSO FORECAST TO MOVE
ACROSS THE SOUTHERN WISCONSIN AFTER MIDNIGHT AND MAY HELP TO KEEP
SOME LIGHT SNOW GOING AFTER MIDNIGHT ESPECIALLY OVER THE
SOUTHEAST HALF OF THE FORECAST AREA. HOWEVER...LOOKING AT SURFACE
OBSERVATIONS OVER IOWA...VSBYS NOT VERY LOW AND WERE IN THE 2 TO 4
MILE RANGE. IN FACT THE LATEST HRRR AND RUC FORECASTS SEEM TO
SIGNIFICANTLY DISSOLVE THE AREA OF QPF AS THIS FEATURE APPROACHES
WISCONSIN.
FORCING ACROSS THE NORTHWEST THIRD OF THE FORECAST AREA NOT
EXPECTED TO BE VERY STRONG AND THUS FAR SNOWFALL RATES UP THERE
HAVE BEEN QUITE LIGHT WITH VSBYS GENERALLY IN THE 2 TO 4 MILE
RANGE. WILL SEE HOW THE SHORTWAVE MOVING OUT OF IOWA EVOLVES LATER
THIS EVENING...BUT IF CURRENT TRENDS CONTINUE MAY NEED TO CANCEL ADVISORY
UP THERE.
FOR NOW WILL KEEP ADVISORY GOING OVER ENTIRE FORECAST AREA AND
WILL REVIST A BIT LATER THIS EVENING. BOTTOM LINE IS IT APPEARS
MOST SIGNIFICANT SNOWFALL WILL BE FOCUSED OVER THE FOX VALLEY AND
LAKESHORE. APPEARS FINAL SNOWFALL TOTALS WILL BE ON THE LOW END OF
CURRENT FORECAST.
&&
.SHORT TERM...TONIGHT AND MONDAY
ISSUED AT 232 PM CST SUN DEC 8 2013
LATEST RUC ANALYSIS AND SATELLITE/RADAR IMAGERY SHOW ONE SHORTWAVE
TROUGH MOVING INTO SOUTHWEST WISCONSIN THIS AFTERNOON...WHILE
ANOTHER WAVE NOW ENTERING THE CENTRAL GREAT PLAINS. AHEAD OF THE
FORMER SHORTWAVE...WEAK ISENTROPIC ASCENT IS PRODUCING A WIDESPREAD
SWATH OF LIGHT SNOW ACROSS THE STATE. THE BETTER SNOWS WITH THE
FIRST WAVE ARE STILL ACROSS IOWA AT THE MOMENT...WHERE VSBYS ARE
DOWN TO A HALF MILE AND WIDESPREAD 1-2 INCHES ARE BEING REPORTED SO
FAR. FURTHER CONCERNS RESIDE ALONG THE LAKE SHORE WHERE LAKE
ENHANCEMENT IS OCCURRING OVER CENTRAL AND SOUTHERN PARTS OF THE LAKE
MICHIGAN SHORELINE. EARLIER REPORTS SHOWED 1-1.5 INCH PER HOUR
SNOWFALL RATES IN THOSE LAKE ENHANCED BANDS. ONE OF THESE BANDS IS
APPROACHING MANITOWOC...BUT APPEARS TRANSIENT IN A LOW LEVEL
CONVERGENT ZONE. LOW LEVEL WINDS ARE JUST STARTING TO TURN TO THE
SOUTHEAST SO WILL NEED TO WATCH THESE TRENDS FOR THE REST OF THE
AFTERNOON. AS THE SHORTWAVES MOVE ACROSS THE ARE TONIGHT...SNOWFALL
AMOUNTS AND IMPACTS ARE THE MAIN FORECAST CONCERN.
TONIGHT...SHORTWAVE TROUGH OVER COLORADO WILL QUICKLY EJECT
NORTHEAST A DRIVE A STRENGTHENING...ALTHOUGH STILL RELATIVELY
WEAK...AREA OF LOW PRESSURE FROM THE CENTRAL GREAT PLAINS AND ACROSS
SOUTHEAST WISCONSIN TONIGHT. FORCING AHEAD OF THE SHORTWAVE IN THE
FORM OF -DIVQ...UPPER DIVERGENCE...AND ISENTROPIC ASCENT IS ONLY
MODEST...BUT BUFKIT SOUNDINGS FROM THE NAM/GFS/SREF ALL INDICATE A
150-200MB DEEP DENDRITIC GROWTH ZONE BETWEEN APPROX 850-650MB OVER
CENTRAL AND NORTHEAST WISCONSIN. THIS SUGGESTS THAT WHATEVER WEAK
TO MODERATE LIFT THAT OCCURS...SNOW FLAKE PRODUCTION WILL BE VERY
EFFICIENT AND SNOW TO LIQUID RATIOS WILL BE QUITE HIGH. GENERALLY
WENT WITH A 19-20:1 RATIO...ALTHOUGH A LITTLE LOWER NEAR THE LAKE
MICHIGAN SHORELINE WHERE ONSHORE FLOW WILL LEAD TO SLIGHTLY WARMER
LOW LEVEL THERMAL PROFILES. THE BULK OF THE SNOW LOOKS TO OCCUR IN
A COUPLE WAVES. THE FIRST WILL ARRIVE LATE THIS AFTERNOON INTO EARLY
THIS EVENING FROM THE FIRST AREA OF SNOW OVER IOWA AND SE
MINNESOTA...FOLLOW BY THE MAIN SHORTWAVE AND SURFACE LOW OVER
COLORADO. PLENTY OF 1-3" INCH REPORTS UPSTREAM OVER IOWA...AND FEW
4-6 INCH REPORTS OVER EASTERN NEBRASKA AS WELL. WILL INCREASE
AMOUNTS A LITTLE OVER N-C WISCONSIN TO AROUND 3 INCHES. THE PRIMARY
CONCERN THOUGH WILL BE ALONG THE LAKE SHORE WHERE WINDS WILL BE
TURNING TO THE EAST AND SOUTHEAST THIS EVENING. THE LAKE ENHANCEMENT
OVER SOUTHEAST WISCONSIN APPEARS TO BE FLUCTUATING...AS A CONVERGENT
BAND LIFTS NORTH. BUT EARLIER SNOWFALL RATES WHERE ENHANCEMENT TOOK
PLACE ARE ALARMING. LOOKS LIKE A GOOD 9-12 HOURS OF ENHANCEMENT
POSSIBLE OVER NORTHEAST WISCONSIN. WILL GO WITH WIDESPREAD 2-4
INCHES EXCEPT NEAR THE LAKESHORE WHERE 5-6 INCHES WILL BE POSSIBLE.
HEADLINES WILL REMAIN THE SAME...AND WILL PASS ALONG LAKE
ENHANCEMENT CONCERNS TO THE EVENING SHIFT.
MONDAY...THE SNOW WILL BE ENDING EARLY MONDAY MORNING OVER NORTHEAST
WISCONSIN AS THE SURFACE LOW PULLS AWAY. WEST WINDS WILL BE
STRENGTHENING IN THE WAKE OF THE LOW AND COLD ADVECTING AT THE SAME
TIME. TEMPS WILL REMAIN NEARLY STEADY OR FALL SLIGHTLY DURING THE
DAY...DESPITE CLEARING TAKING PLACE. WITH WINDS GUSTING TO 30
MPH...APPARENT TEMPS WILL BE FALLING TO NEAR 20 BELOW ZERO OVER
CENTRAL AND NORTH-CENTRAL WISCONSIN DURING THE AFTERNOON. WILL
LIKELY NEED WIND CHILL HEADLINES...BUT WITH THE ONGOING SNOW
ADVISORY...WILL NOT ISSUE ANOTHER HEADLINE. MORNING TO MIDDAY HIGHS
IN THE MIDDLE SINGLE DIGITS NORTH TO THE UPPER TEENS NEAR THE LAKE
SHORE.
.LONG TERM...MONDAY NIGHT THROUGH SUNDAY
ISSUED AT 232 PM CST SUN DEC 8 2013
VERY COLD AIR WILL REMAIN FIRMLY ENTRENCHED ACROSS THE AREA
MONDAY NIGHT. EXPECT WINDS CHILLS TO DROP TO AROUND 25 BELOW
ACROSS THE NORTH. HOWEVER...TEMPERATURES ARE EXPECTED TO
MODIFY SOME LATE MONDAY NIGHT DUE TO INCREASING CLOUDINESS
AND AHEAD OF APPROACHING SYSTEM. INCREASED CHANCES OF SNOW
ACROSS THE NORTHWEST HALF OF THE FORECAST AREA. INCREASED SNOW
CHANCES SIGNIFICANTLY ON TUESDAY MORNING AS SYSTEM MOVES ACROSS
THE AREA. ALSO...PRECIPITATION TOTALS WILL BE LIGHT...SNOW RATIOS
WOULD SUGGEST LESS THAN AN INCH OF NEW SNOW TUESDAY MORNING. THE
HIGHEST SNOWFALL TOTALS WILL BE ACROSS THE NORTH.
MOST OF THE MODELS NOW BRING CLIPPER SYSTEM SOUTH OF THE AREA
TUESDAY NIGHT. THE ONLY EXCEPTION WAS THE ECMWF...THUS WILL CONTINUE
CHANCES ACROSS THE SOUTHERN HALF OF THE FORECAST AREA. THE GFS MODELS
HAS BEEN WAFFLING ON NORTHWARD EXTENT OF THE PRECIPITATION FIELD. VERY
COLD AIR IS EXPECTED WEDNESDAY MORNING. ANOTHER SYSTEM EXPECTED TO
PASS ACROSS THE NORTH THURSDAY/THURSDAY NIGHT. LOW CONFIDENCE ON WHEN
THIS SYSTEM WOULD BRING A SMALL CHANCE OF LIGHT SNOW DURING THIS PERIOD.
CURRENT FORECAST HAS LIGHT SNOW IN THE FORECAST THURSDAY NIGHT...BUT
LATER SHIFTS MAY NEED TO SPEED UP THE SNOW AND ADD A CHANCE TO THE
THURSDAY PERIOD. THE ARCTIC AIR WILL MODIFY FRIDAY INTO NEXT WEEKEND
WITH HIGHS IN THE UPPER TEENS TO MIDDLE 20S.
&&
.AVIATION...FOR 06Z TAF ISSUANCE
ISSUED AT 1144 PM CST SUN DEC 8 2013
WEAK LOW PRESSURE WILL CONTINUE TO MOVE EAST OF THE FORECAST AREA
OVERNIGHT. LIGHT SNOW WITH GENERALLY MVFR CIGS AND VSBYS WILL
PREVAIL OVER MOST OF THE FORECAST AREA THROUGH 12Z MONDAY. FEW
AREAS OF IFR CIGS OVER FOX VALLEY AND LAKESHORE WHERE LIGHT SNOW
WILL BE A BIT HEAVIER THROUGH ABOUT 09Z. MVFR CIGS TO PERSIST
UNTIL ABOUT 18Z MONDAY AND WILL BECOME SCT FROM WEST TO EAST
DURING THE AFTERNOON. WESTERLY BOUNDARY LAYER WINDS WILL INCREASE
SUBSTANTIALLY BY LATE MORNING WITH GUSTS OF 25 TO 30 MPH DURING
THE AFTERNOON.
&&
.GRB WATCHES/WARNINGS/ADVISORIES...
WINTER WEATHER ADVISORY UNTIL 6 AM CST MONDAY FOR WIZ013-020>022-
030-031-035>040-045-048>050-073-074.
&&
$$
UPDATE.........ESB
SHORT TERM.....MPC
LONG TERM......ECKBERG
AVIATION.......ESB
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
304 AM CST WED DEC 11 2013
.DISCUSSION...
920 PM CST
THE CURRENT WINTER WEATHER ADVISORY FOR OVERNIGHT AND WEDNESDAY
MORNING CONTINUES AS IS WITH NO MAJOR CHANGES TO GOING FORECAST
SNOWFALL TIMING OR TOTAL AMOUNTS. HAVE ADDED PATCHY BLOWING SNOW
IN FOR THE MORNING IN THE FAR WEST AND SPREAD IT EASTWARD DURING
THE AFTERNOON AS THE COLD...OR SHOULD WE SAY COLDER...AIR SURGES
BACK IN.
THE POSITIVES TOWARD SNOWFALL WITH THIS SYSTEM REMAIN IN
OBSERVATIONAL AND SHORT TERM GUIDANCE...WITH HIGHER SNOW-TO-
LIQUID RATIOS AND TEMPORARY MODEST RATES...WHILE THE SUBTLE
CAVEATS OF A SOMEWHAT WEAK WAVE AND LOW COLUMN MOISTURE ARE LIKELY
TO BE OFFSET BY THESE ENOUGH TO PRODUCE 2-3.5" SNOWFALL AMOUNTS
AND LIKELY SCATTERED HIGHER AMOUNTS WITHIN THE ADVISORY AREA.
RADAR ECHOES ARE ON THE UPWARD TREND ACROSS CENTRAL IA WITHIN THE
WARM AIR ADVECTION WING OF THE SHORT WAVE SEEN ON WATER VAPOR
PROGRESSING EAST SOUTHEAST. THIS WAVE WILL TURN MORE EAST ALONG A
WELL-DEFINED 850-600MB BAROCLINIC ZONE SEEN ON THIS EVES UPPER
AIR DATA. HAVE ALREADY NOTED 3/4SM VISIBILITY IN IA...LIKELY
ASSOCIATED WITH ONE HALF TO ONE INCH PER HOUR TYPE RATES. WITH
CLIPPER SYSTEMS IT SEEMS THAT THE LOWEST VISIBILITY CAN OFTEN BE
EXTRAPOLATED OUT ALONG THE PATH GIVEN THE WAVE MAINTAINS ITS
INTENSITY. THE RAP CONTINUES TO SHOW A FAIRLY QUICK PROGRESSION
OF THE LEADING EDGE OF SNOW OVER MUCH OF THE FORECAST AREA BETWEEN
12AM-3AM...SO DID NOT GET FANCY WITH TRYING TO ADJUST THE ADVISORY
START TIME. TEMPORARY WEST-TO-EAST BANDED SNOW OVERNIGHT WOULD
SEEM PROBABLE IN NORTH CENTRAL IL...MAYBE INTO THE CHICAGO
METRO...ALONG THE BAROCLINIC ZONE AND FAIRLY WELL-DEFINED
MOISTURE CONVERGENCE. CONVECTIVE ALLOWING/HIGH RES GUIDANCE
INDICATES HIGHER REFLECTIVITY AS WELL IN THE 3-8 AM PERIOD. SNOW
LOOKS TO LINGER OVER CHICAGO THROUGH THE END OF THE ADVISORY TIME.
FORECAST SOUNDINGS CONTINUE TO INDICATE A VERY DEEP DENDRITIC
GROWTH AREA WITH NOT OVERLY HIGH WINDS BELOW THE CLOUD BASE FOR
FRAGMENTING. EVEN THE 00Z DVN SOUNDING HAD THE WET BULB
TEMPERATURE BASICALLY WITHIN THE DENDRITIC GROWTH AREA ALL THE WAY
TO ~10000 FT! THIS SHOULD ALLOW FOR GOOD EFFICIENCY (20:1) OF
MEAGER PWAT VALUES UNDER 0.2 INCH AND MIXING RATIOS IN THE CLOUD
LAYER OF 1-1.5 G/KG. SO WE CONTINUE A LITTLE HIGHER THAT MOST
GUIDANCE FOR SNOWFALL AMOUNTS.
THE MOST PROBABLE TIMING FOR HEAVIEST SNOWFALL RATES IN ROCKFORD
IS 2-6 AM AND CHICAGO IS 4-8 AM. TEMPERATURES SHOULD CONTINUE TO
INCH UP PRIOR TO THE SNOWFALL...AND THEN HOLD STEADY IN THE MID-
UPPER TEENS DURING THE SNOW.
MTF
//PREV DISCUSSION...
250 PM...FORECAST CONCERNS INCLUDE ACCUMULATING SNOW TONIGHT INTO
WEDNESDAY MORNING...VERY COLD TEMPERATURES/WIND CHILLS WEDNESDAY
NIGHT AND ANOTHER POSSIBLE ACCUMULATING SNOW EVENT LATE FRIDAY
NIGHT INTO SATURDAY.
TEMPERATURES HAVE REBOUNDED QUITE A BIT FROM THIS MORNING/S SUB
ZERO READINGS WITH MANY AREAS IN THE LOWER/MID 20S. AS GUSTY WINDS
DIMINISH LATE THIS AFTERNOON INTO THIS EVENING...EXPECT TEMPS TO
STEADILY DROP INTO THE LOWER/MID TEENS AND THEN BECOME STEADY BY
LATE EVENING AND BEGIN RISING OVERNIGHT...POSSIBLY INTO THE LOWER
20S BY DAYBREAK.
A WEAK CLIPPER SYSTEM WILL MOVE ACROSS IOWA THIS EVENING AND THEN
ACROSS NORTHERN IL OVERNIGHT AND INTO NORTHWEST INDIANA WEDNESDAY
MORNING. FAIRLY GOOD AGREEMENT AMONG THE MODELS WITH A BAND OF
SNOW SPREADING INTO THE WESTERN CWA AROUND/SHORTLY AFTER MIDNIGHT
AND THEN ACROSS THE REST OF THE AREA DURING THE EARLY MORNING
HOURS...BEFORE SUNRISE. WHILE QPF AMOUNTS MAY ONLY RANGE IN THE
0.15 INCH RANGE...THE AIRMASS IS QUITE COLD AND EXPECT SNOW/WATER
RATIOS IN THE 18:1 TO 20:1 RANGE. THUS THE SNOW SHOULD BE QUITE
DRY AND FLUFFY. HAVE BUMPED QPF AMOUNTS AND SNOWFALL AMOUNTS UP
SLIGHTLY...GENERALLY IN THE 2.5 TO 3 INCH RANGE ALONG AND NORTH OF
INTERSTATE 80. AMOUNTS WILL QUICKLY TAPER OFF INTO THE SOUTHERN
THIRD OF THE CWA. THIS LOW BEGINS TO FILL SOME BY WEDNESDAY
MORNING AND AMOUNTS MAY BE HIGHER WESTERN AREAS THEN EASTERN
AREAS. THE ONE CONCERNING FACTOR IS THE GROWTH ZONE OF -10C TO
-14C WHICH BASED OF THE FORECAST SOUNDINGS COULD BE 150MB TO EVEN
200MB DEEP. THIS COULD ALLOW FOR SOME EFFICIENT SNOW DEVELOPMENT
ALONG WITH LARGE FLAKES...WHICH WOULD ALLOW FOR EVEN HIGHER
SNOWFALL AMOUNTS. THIS COULD ALSO LEAD TO SNOWFALL RATES
APPROACHING AN INCH AN HOUR FOR AT LEAST A SHORT TIME. WITH ALL
THIS IN MIND...WILL BE EXTENDING THE SNOW ADVISORY NORTH TO
INCLUDE THE FOUR NORTHERN COUNTIES AND MENTIONING STORM TOTAL
SNOWFALL AMOUNTS OF 2 TO 4 INCHES...WITH SOME UNCERTAINTY
REGARDING HOW WIDESPREAD THE 3 TO 4 INCH AMOUNTS MAY MATERIALIZE.
THE SNOW WILL TAPER OFF QUICKLY FROM WEST TO EAST AFTER SUNRISE
WITH NORTHWEST WINDS INCREASING AS THE SNOW ENDS AND THEN
REMAINING GUSTY INTO THE AFTERNOON. WIND GUSTS INTO THE 20-25 MPH
RANGE LOOK REASONABLE WHICH MAY CAUSE SOME BLOWING AND DRIFTING
SNOW BUT WILL MAINTAIN CURRENT ADVISORY EXPIRATION TIME OF 16Z
WEDNESDAY FOR NOW.
HIGH TEMPS WEDNESDAY WILL BE REACHED IN THE MORNING WITH STEADILY
FALLING TEMPS THROUGH THE AFTERNOON INTO WEDNESDAY NIGHT...WHICH
IS SHAPING UP TO BE VERY SIMILAR TO THIS MORNING. TEMPERATURES
WILL DIVE IN THE EVENING AND THEN BEGIN TO STEADY OVERNIGHT AND
POSSIBLY BEGIN TO RISE BY THURSDAY MORNING AS CLOUD COVER AND WEAK
WARM ADVECTION MOVE ACROSS THE REGION. BUT WITH A FRESH SNOW COVER
AND CLEARING SKIES...TEMPS SHOULD FALL BELOW ZERO JUST ABOUT
EVERYWHERE WITH THE USUAL COLD SPOTS PERHAPS INTO THE -10 RANGE.
THIS COMBINED WITH WESTERLY WINDS TURNING SOUTHWESTERLY...BUT IN
THE 10 MPH RANGE WILL PRODUCE WIND CHILLS FROM -15 TO -25 WITH
SOME LOCALLY LOWER VALUES. IF THESE TRENDS CONTINUE A WIND CHILL
ADVISORY MAY BE NEEDED DURING THIS TIME PERIOD.
TEMPS MODERATE SLIGHTLY THURSDAY INTO FRIDAY...THOUGH STILL BELOW
NORMAL. A COLD FRONT WILL SAG SOUTH ACROSS THE LAKES REGION
THURSDAY NIGHT AND FRIDAY...REACHING NORTHERN IL FRIDAY AFTERNOON.
MEANWHILE...LOW PRESSURE OVER THE SOUTHERN PLAINS LIFTS NORTHEAST
ACROSS THE OHIO VALLEY SATURDAY AND TO THE EASTERN LAKES BY SUNDAY
MORNING. A PROLONGED PERIOD OF LIGHT TO MODERATE SNOW WILL LIKELY
BEGIN FRIDAY NIGHT AND CONTINUE THROUGH MUCH OF SATURDAY WITH SOME
DIFFERENCES REGARDING THE CORRIDOR OF HEAVIEST QPF. BUT WITH
AMOUNTS IN THE 0.3 TO 0.5 RANGE...SEVERAL INCHES OF SNOW WILL BE
POSSIBLE. BUT WITH WARMER TEMPERATURES...PERHAPS NEAR FREEZING ON
SATURDAY...SNOW RATIOS SHOULD BE CLOSER TO 10:1 WITH A HEAVIER/WET
SNOW MOST LIKELY.
ANOTHER COLD DUMP SATURDAY NIGHT INTO SUNDAY. AND WHILE THE
STRENGTH OF COLD AIR IS STILL A BIT UNCERTAIN HAVE LOWERED TEMPS
SATURDAY NIGHT AND SUNDAY AND IF THIS MORNING AND WEDNESDAY NIGHT
ARE GOOD INDICATORS...TEMPS COULD BE SIGNIFICANTLY COLDER THAN
CURRENTLY ADVERTISED. CMS
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 06Z...
* MODERATE SNOWFALL INTO THE PREDAWN HOURS REDUCING VSBY TO IFR AND
RESULTING IN 1 TO 3 INCHES OF SNOW ACCUMULATION.
BMD
//DISCUSSION...UPDATED 06Z...
WINTER SYSTEM IS BRINGING AREA OF SNOW OVER IOWA LATE THIS
EVENING...AND WILL BE SPREADING EAST ACROSS NORTHERN ILLINOIS OVER
THE NEXT FEW HOURS. EXPECT VSBY TO FAIRLY QUICKLY DROP TO 1-2SM AS
THE SNOW BEGINS. THE BEST FORCING AND HEAVIEST SNOWFALL IS EXPECTED
TO BETWEEN ROUGHLY 8Z AND 12Z THIS EVENING WHERE VSBY MAY FALL UNDER
A MILE. QUITE A BIT A VARIABILITY IN CIGS UPSTREAM...BUT SHOULD
MAINLY BE IN THE 015-020 RANGE WITH TEMPO LOWER POSSIBLY IFR CIGS AT
TIMES. SNOW WILL BEGIN TO LET UP AROUND DAYBREAK WEDNESDAY MORNING
WHEN 2 TO 4 INCHES OF SNOW IS EXPECTED TO HAVE FALLEN. NORTHWEST
WINDS WITH GUSTS TO AROUND 20 KT ARE EXPECTED FROM MID MORNING
THROUGH MID AFTERNOON...THEN SHOULD EASE AND BEGIN TO BACK TO TO
WEST WEDNESDAY EVENING AS HIGH PRESSURE BUILDS DOWNSTATE.
BMD
//ORD AND MDW CONFIDENCE...UPDATED 06Z...
* HIGH CONFIDENCE IN SNOWFALL INTENSITY AND TIMING.
* MEDIUM-HIGH CONFIDENCE IN VSBY TRENDS.
* MEDIUM CONFIDENCE IN CIG TRENDS...LOWER CONFIDENCE IN TIMING
IMPROVEMENT TO VFR MIDDAY WEDNESDAY.
BMD
//OUTLOOK FOR ORD/MDW FOR 12Z THURSDAY-12Z TUESDAY...UPDATED 00Z...
THURSDAY...VFR.
FRIDAY...SNOW ESPECIALLY OVERNIGHT.
SATURDAY...SNOW DURING THE DAY...TAPERING OFF AT NIGHT. MVFR OR
LOWER PSBL.
SUNDAY...CHANCE OF SNOW EARLY WITH CONDITIONS IMPROVING TO VFR
THROUGH THE DAY.
MONDAY...CHANCE OF SNOW...VFR.
JEE
&&
.MARINE...
214 AM CST
WINDS HAVE DIMINISHED BELOW GALES BUT WILL REMAIN BREEZY THROUGH AT
LEAST LATE THURSDAY AS A STRONG HIGH BUILDS ACROSS THE PLAINS
TOWARDS THE MID MISSISSIPPI VALLEY RESULTING IN A MODERATE PRESSURE
GRADIENT OVER THE LAKE. WILL HOIST A SMALL CRAFT ADVISORY FOR THE
ILLINOIS AND INDIANA NEARSHORE WATERS STARTING MID MORNING TODAY.
THE ADVISORY FOR THE ILLINOIS WATERS WILL RUN THROUGH LATE THIS
EVENING WHEN WINDS SHOULD DROP BELOW CRITERIA OVERNIGHT WITH
OFFSHORE FLOW. THE INDIANA SHORES THOUGH WILL LIKELY EXPERIENCE
HAZARDOUS CONDITIONS FOR SMALL CRAFT THROUGH MID TO LATE THURSDAY AS
WAVES SLOWLY DIMINISH IN THE MODERATE NORTHWEST FLOW. WINDS BRIEFLY
ABATE THURSDAY NIGHT INTO EARLY FRIDAY AS A NEUTRAL POINT PUSHES
OVER THE REGION...BUT THEN ARE EXPECTED TO PICK UP AGAIN OUT OF THE
EAST/NORTHEAST LATE FRIDAY AS LOW PRESSURE DEEPENS OVER THE LOWER
MISSISSIPPI VALLEY AND LIFTS INTO THE OHIO VALLEY SATURDAY. A RIDGE
WILL BUILD ACROSS THE LAKE LATE NEXT WEEKEND AND SHOULD ALLOW FOR
ANOTHER LULL IN THE WINDS.
BMD
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...WINTER WEATHER ADVISORY...ILZ003-ILZ004-ILZ005-ILZ006-ILZ008-
ILZ010-ILZ011-ILZ012-ILZ013-ILZ014-ILZ019-ILZ020-ILZ021-
ILZ022 UNTIL 10 AM WEDNESDAY.
WIND CHILL ADVISORY...ILZ003-ILZ004-ILZ005-ILZ006-ILZ008-ILZ010-
ILZ011-ILZ012-ILZ013-ILZ014-ILZ019-ILZ020-ILZ021-ILZ022-
ILZ023-ILZ032...6 PM WEDNESDAY TO 5 AM THURSDAY.
IN...WIND CHILL ADVISORY...INZ001-INZ002...6 PM WEDNESDAY TO 5 AM
THURSDAY.
WINTER WEATHER ADVISORY...INZ001-INZ002 UNTIL 10 AM WEDNESDAY.
LM...SMALL CRAFT ADVISORY...LMZ740-LMZ741-LMZ742-LMZ743...9 AM
WEDNESDAY TO 10 PM WEDNESDAY.
SMALL CRAFT ADVISORY...LMZ744-LMZ745...9 AM WEDNESDAY TO 3 PM
THURSDAY.
&&
$$
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
215 AM CST WED DEC 11 2013
.DISCUSSION...
920 PM CST
THE CURRENT WINTER WEATHER ADVISORY FOR OVERNIGHT AND WEDNESDAY
MORNING CONTINUES AS IS WITH NO MAJOR CHANGES TO GOING FORECAST
SNOWFALL TIMING OR TOTAL AMOUNTS. HAVE ADDED PATCHY BLOWING SNOW
IN FOR THE MORNING IN THE FAR WEST AND SPREAD IT EASTWARD DURING
THE AFTERNOON AS THE COLD...OR SHOULD WE SAY COLDER...AIR SURGES
BACK IN.
THE POSITIVES TOWARD SNOWFALL WITH THIS SYSTEM REMAIN IN
OBSERVATIONAL AND SHORT TERM GUIDANCE...WITH HIGHER SNOW-TO-
LIQUID RATIOS AND TEMPORARY MODEST RATES...WHILE THE SUBTLE
CAVEATS OF A SOMEWHAT WEAK WAVE AND LOW COLUMN MOISTURE ARE LIKELY
TO BE OFFSET BY THESE ENOUGH TO PRODUCE 2-3.5" SNOWFALL AMOUNTS
AND LIKELY SCATTERED HIGHER AMOUNTS WITHIN THE ADVISORY AREA.
RADAR ECHOES ARE ON THE UPWARD TREND ACROSS CENTRAL IA WITHIN THE
WARM AIR ADVECTION WING OF THE SHORT WAVE SEEN ON WATER VAPOR
PROGRESSING EAST SOUTHEAST. THIS WAVE WILL TURN MORE EAST ALONG A
WELL-DEFINED 850-600MB BAROCLINIC ZONE SEEN ON THIS EVES UPPER
AIR DATA. HAVE ALREADY NOTED 3/4SM VISIBILITY IN IA...LIKELY
ASSOCIATED WITH ONE HALF TO ONE INCH PER HOUR TYPE RATES. WITH
CLIPPER SYSTEMS IT SEEMS THAT THE LOWEST VISIBILITY CAN OFTEN BE
EXTRAPOLATED OUT ALONG THE PATH GIVEN THE WAVE MAINTAINS ITS
INTENSITY. THE RAP CONTINUES TO SHOW A FAIRLY QUICK PROGRESSION
OF THE LEADING EDGE OF SNOW OVER MUCH OF THE FORECAST AREA BETWEEN
12AM-3AM...SO DID NOT GET FANCY WITH TRYING TO ADJUST THE ADVISORY
START TIME. TEMPORARY WEST-TO-EAST BANDED SNOW OVERNIGHT WOULD
SEEM PROBABLE IN NORTH CENTRAL IL...MAYBE INTO THE CHICAGO
METRO...ALONG THE BAROCLINIC ZONE AND FAIRLY WELL-DEFINED
MOISTURE CONVERGENCE. CONVECTIVE ALLOWING/HIGH RES GUIDANCE
INDICATES HIGHER REFLECTIVITY AS WELL IN THE 3-8 AM PERIOD. SNOW
LOOKS TO LINGER OVER CHICAGO THROUGH THE END OF THE ADVISORY TIME.
FORECAST SOUNDINGS CONTINUE TO INDICATE A VERY DEEP DENDRITIC
GROWTH AREA WITH NOT OVERLY HIGH WINDS BELOW THE CLOUD BASE FOR
FRAGMENTING. EVEN THE 00Z DVN SOUNDING HAD THE WET BULB
TEMPERATURE BASICALLY WITHIN THE DENDRITIC GROWTH AREA ALL THE WAY
TO ~10000 FT! THIS SHOULD ALLOW FOR GOOD EFFICIENCY (20:1) OF
MEAGER PWAT VALUES UNDER 0.2 INCH AND MIXING RATIOS IN THE CLOUD
LAYER OF 1-1.5 G/KG. SO WE CONTINUE A LITTLE HIGHER THAT MOST
GUIDANCE FOR SNOWFALL AMOUNTS.
THE MOST PROBABLE TIMING FOR HEAVIEST SNOWFALL RATES IN ROCKFORD
IS 2-6 AM AND CHICAGO IS 4-8 AM. TEMPERATURES SHOULD CONTINUE TO
INCH UP PRIOR TO THE SNOWFALL...AND THEN HOLD STEADY IN THE MID-
UPPER TEENS DURING THE SNOW.
MTF
//PREV DISCUSSION...
250 PM...FORECAST CONCERNS INCLUDE ACCUMULATING SNOW TONIGHT INTO
WEDNESDAY MORNING...VERY COLD TEMPERATURES/WIND CHILLS WEDNESDAY
NIGHT AND ANOTHER POSSIBLE ACCUMULATING SNOW EVENT LATE FRIDAY
NIGHT INTO SATURDAY.
TEMPERATURES HAVE REBOUNDED QUITE A BIT FROM THIS MORNING/S SUB
ZERO READINGS WITH MANY AREAS IN THE LOWER/MID 20S. AS GUSTY WINDS
DIMINISH LATE THIS AFTERNOON INTO THIS EVENING...EXPECT TEMPS TO
STEADILY DROP INTO THE LOWER/MID TEENS AND THEN BECOME STEADY BY
LATE EVENING AND BEGIN RISING OVERNIGHT...POSSIBLY INTO THE LOWER
20S BY DAYBREAK.
A WEAK CLIPPER SYSTEM WILL MOVE ACROSS IOWA THIS EVENING AND THEN
ACROSS NORTHERN IL OVERNIGHT AND INTO NORTHWEST INDIANA WEDNESDAY
MORNING. FAIRLY GOOD AGREEMENT AMONG THE MODELS WITH A BAND OF
SNOW SPREADING INTO THE WESTERN CWA AROUND/SHORTLY AFTER MIDNIGHT
AND THEN ACROSS THE REST OF THE AREA DURING THE EARLY MORNING
HOURS...BEFORE SUNRISE. WHILE QPF AMOUNTS MAY ONLY RANGE IN THE
0.15 INCH RANGE...THE AIRMASS IS QUITE COLD AND EXPECT SNOW/WATER
RATIOS IN THE 18:1 TO 20:1 RANGE. THUS THE SNOW SHOULD BE QUITE
DRY AND FLUFFY. HAVE BUMPED QPF AMOUNTS AND SNOWFALL AMOUNTS UP
SLIGHTLY...GENERALLY IN THE 2.5 TO 3 INCH RANGE ALONG AND NORTH OF
INTERSTATE 80. AMOUNTS WILL QUICKLY TAPER OFF INTO THE SOUTHERN
THIRD OF THE CWA. THIS LOW BEGINS TO FILL SOME BY WEDNESDAY
MORNING AND AMOUNTS MAY BE HIGHER WESTERN AREAS THEN EASTERN
AREAS. THE ONE CONCERNING FACTOR IS THE GROWTH ZONE OF -10C TO
-14C WHICH BASED OF THE FORECAST SOUNDINGS COULD BE 150MB TO EVEN
200MB DEEP. THIS COULD ALLOW FOR SOME EFFICIENT SNOW DEVELOPMENT
ALONG WITH LARGE FLAKES...WHICH WOULD ALLOW FOR EVEN HIGHER
SNOWFALL AMOUNTS. THIS COULD ALSO LEAD TO SNOWFALL RATES
APPROACHING AN INCH AN HOUR FOR AT LEAST A SHORT TIME. WITH ALL
THIS IN MIND...WILL BE EXTENDING THE SNOW ADVISORY NORTH TO
INCLUDE THE FOUR NORTHERN COUNTIES AND MENTIONING STORM TOTAL
SNOWFALL AMOUNTS OF 2 TO 4 INCHES...WITH SOME UNCERTAINTY
REGARDING HOW WIDESPREAD THE 3 TO 4 INCH AMOUNTS MAY MATERIALIZE.
THE SNOW WILL TAPER OFF QUICKLY FROM WEST TO EAST AFTER SUNRISE
WITH NORTHWEST WINDS INCREASING AS THE SNOW ENDS AND THEN
REMAINING GUSTY INTO THE AFTERNOON. WIND GUSTS INTO THE 20-25 MPH
RANGE LOOK REASONABLE WHICH MAY CAUSE SOME BLOWING AND DRIFTING
SNOW BUT WILL MAINTAIN CURRENT ADVISORY EXPIRATION TIME OF 16Z
WEDNESDAY FOR NOW.
HIGH TEMPS WEDNESDAY WILL BE REACHED IN THE MORNING WITH STEADILY
FALLING TEMPS THROUGH THE AFTERNOON INTO WEDNESDAY NIGHT...WHICH
IS SHAPING UP TO BE VERY SIMILAR TO THIS MORNING. TEMPERATURES
WILL DIVE IN THE EVENING AND THEN BEGIN TO STEADY OVERNIGHT AND
POSSIBLY BEGIN TO RISE BY THURSDAY MORNING AS CLOUD COVER AND WEAK
WARM ADVECTION MOVE ACROSS THE REGION. BUT WITH A FRESH SNOW COVER
AND CLEARING SKIES...TEMPS SHOULD FALL BELOW ZERO JUST ABOUT
EVERYWHERE WITH THE USUAL COLD SPOTS PERHAPS INTO THE -10 RANGE.
THIS COMBINED WITH WESTERLY WINDS TURNING SOUTHWESTERLY...BUT IN
THE 10 MPH RANGE WILL PRODUCE WIND CHILLS FROM -15 TO -25 WITH
SOME LOCALLY LOWER VALUES. IF THESE TRENDS CONTINUE A WIND CHILL
ADVISORY MAY BE NEEDED DURING THIS TIME PERIOD.
TEMPS MODERATE SLIGHTLY THURSDAY INTO FRIDAY...THOUGH STILL BELOW
NORMAL. A COLD FRONT WILL SAG SOUTH ACROSS THE LAKES REGION
THURSDAY NIGHT AND FRIDAY...REACHING NORTHERN IL FRIDAY AFTERNOON.
MEANWHILE...LOW PRESSURE OVER THE SOUTHERN PLAINS LIFTS NORTHEAST
ACROSS THE OHIO VALLEY SATURDAY AND TO THE EASTERN LAKES BY SUNDAY
MORNING. A PROLONGED PERIOD OF LIGHT TO MODERATE SNOW WILL LIKELY
BEGIN FRIDAY NIGHT AND CONTINUE THROUGH MUCH OF SATURDAY WITH SOME
DIFFERENCES REGARDING THE CORRIDOR OF HEAVIEST QPF. BUT WITH
AMOUNTS IN THE 0.3 TO 0.5 RANGE...SEVERAL INCHES OF SNOW WILL BE
POSSIBLE. BUT WITH WARMER TEMPERATURES...PERHAPS NEAR FREEZING ON
SATURDAY...SNOW RATIOS SHOULD BE CLOSER TO 10:1 WITH A HEAVIER/WET
SNOW MOST LIKELY.
ANOTHER COLD DUMP SATURDAY NIGHT INTO SUNDAY. AND WHILE THE
STRENGTH OF COLD AIR IS STILL A BIT UNCERTAIN HAVE LOWERED TEMPS
SATURDAY NIGHT AND SUNDAY AND IF THIS MORNING AND WEDNESDAY NIGHT
ARE GOOD INDICATORS...TEMPS COULD BE SIGNIFICANTLY COLDER THAN
CURRENTLY ADVERTISED. CMS
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 06Z...
* MODERATE SNOWFALL OVERSPREADING THE TERMINALS LATE THIS EVENING
AND EARLY OVERNIGHT REDUCING VSBY TO IFR OR LOWER AND RESULTING
IN 2 TO 4 INCHES OF SNOW ACCUMULATION.
BMD
//DISCUSSION...UPDATED 06Z...
WINTER SYSTEM IS BRINGING AREA OF SNOW OVER IOWA LATE THIS
EVENING...AND WILL BE SPREADING EAST ACROSS NORTHERN ILLINOIS OVER
THE NEXT FEW HOURS. EXPECT VSBY TO FAIRLY QUICKLY DROP TO 1-2SM AS
THE SNOW BEGINS. THE BEST FORCING AND HEAVIEST SNOWFALL IS EXPECTED
TO BETWEEN ROUGHLY 8Z AND 12Z THIS EVENING WHERE VSBY MAY FALL UNDER
A MILE. QUITE A BIT A VARIABILITY IN CIGS UPSTREAM...BUT SHOULD
MAINLY BE IN THE 015-020 RANGE WITH TEMPO LOWER POSSIBLY IFR CIGS AT
TIMES. SNOW WILL BEGIN TO LET UP AROUND DAYBREAK WEDNESDAY MORNING
WHEN 2 TO 4 INCHES OF SNOW IS EXPECTED TO HAVE FALLEN. NORTHWEST
WINDS WITH GUSTS TO AROUND 20 KT ARE EXPECTED FROM MID MORNING
THROUGH MID AFTERNOON...THEN SHOULD EASE AND BEGIN TO BACK TO TO
WEST WEDNESDAY EVENING AS HIGH PRESSURE BUILDS DOWNSTATE.
BMD
//ORD AND MDW CONFIDENCE...UPDATED 06Z...
* MEDIUM-HIGH CONFIDENCE IN SNOWFALL INTENSITY AND TIMING.
* MEDIUM-HIGH CONFIDENCE IN VSBY TRENDS.
* MEDIUM CONFIDENCE IN CIG TRENDS...LOWER CONFIDENCE IN TIMING
IMPROVEMENT TO VFR MIDDAY WEDNESDAY.
BMD
//OUTLOOK FOR ORD/MDW FOR 12Z THURSDAY-12Z TUESDAY...UPDATED 00Z...
THURSDAY...VFR.
FRIDAY...SNOW ESPECIALLY OVERNIGHT.
SATURDAY...SNOW DURING THE DAY...TAPERING OFF AT NIGHT. MVFR OR
LOWER PSBL.
SUNDAY...CHANCE OF SNOW EARLY WITH CONDITIONS IMPROVING TO VFR
THROUGH THE DAY.
MONDAY...CHANCE OF SNOW...VFR.
JEE
&&
.MARINE...
214 AM CST
WINDS HAVE DIMINISHED BELOW GALES BUT WILL REMAIN BREEZY THROUGH AT
LEAST LATE THURSDAY AS A STRONG HIGH BUILDS ACROSS THE PLAINS
TOWARDS THE MID MISSISSIPPI VALLEY RESULTING IN A MODERATE PRESSURE
GRADIENT OVER THE LAKE. WILL HOIST A SMALL CRAFT ADVISORY FOR THE
ILLINOIS AND INDIANA NEARSHORE WATERS STARTING MID MORNING TODAY.
THE ADVISORY FOR THE ILLINOIS WATERS WILL RUN THROUGH LATE THIS
EVENING WHEN WINDS SHOULD DROP BELOW CRITERIA OVERNIGHT WITH
OFFSHORE FLOW. THE INDIANA SHORES THOUGH WILL LIKELY EXPERIENCE
HAZARDOUS CONDITIONS FOR SMALL CRAFT THROUGH MID TO LATE THURSDAY AS
WAVES SLOWLY DIMINISH IN THE MODERATE NORTHWEST FLOW. WINDS BRIEFLY
ABATE THURSDAY NIGHT INTO EARLY FRIDAY AS A NEUTRAL POINT PUSHES
OVER THE REGION...BUT THEN ARE EXPECTED TO PICK UP AGAIN OUT OF THE
EAST/NORTHEAST LATE FRIDAY AS LOW PRESSURE DEEPENS OVER THE LOWER
MISSISSIPPI VALLEY AND LIFTS INTO THE OHIO VALLEY SATURDAY. A RIDGE
WILL BUILD ACROSS THE LAKE LATE NEXT WEEKEND AND SHOULD ALLOW FOR
ANOTHER LULL IN THE WINDS.
BMD
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...WINTER WEATHER ADVISORY...ILZ003-ILZ004-ILZ005-ILZ006-ILZ008-
ILZ010-ILZ011-ILZ012-ILZ013-ILZ014-ILZ019-ILZ020-ILZ021-
ILZ022 UNTIL 10 AM WEDNESDAY.
IN...WINTER WEATHER ADVISORY...INZ001-INZ002 UNTIL 10 AM WEDNESDAY.
LM...NONE.
&&
$$
VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE)
FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
WWW.FACEBOOK.COM/US.NATIONALWEATHERSERVICE.CHICAGO.GOV
WWW.TWITTER.COM/NWSCHICAGO
WWW.YOUTUBE.COM/NWSCHICAGO
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
1147 PM CST TUE DEC 10 2013
.DISCUSSION...
920 PM CST
THE CURRENT WINTER WEATHER ADVISORY FOR OVERNIGHT AND WEDNESDAY
MORNING CONTINUES AS IS WITH NO MAJOR CHANGES TO GOING FORECAST
SNOWFALL TIMING OR TOTAL AMOUNTS. HAVE ADDED PATCHY BLOWING SNOW
IN FOR THE MORNING IN THE FAR WEST AND SPREAD IT EASTWARD DURING
THE AFTERNOON AS THE COLD...OR SHOULD WE SAY COLDER...AIR SURGES
BACK IN.
THE POSITIVES TOWARD SNOWFALL WITH THIS SYSTEM REMAIN IN
OBSERVATIONAL AND SHORT TERM GUIDANCE...WITH HIGHER SNOW-TO-
LIQUID RATIOS AND TEMPORARY MODEST RATES...WHILE THE SUBTLE
CAVEATS OF A SOMEWHAT WEAK WAVE AND LOW COLUMN MOISTURE ARE LIKELY
TO BE OFFSET BY THESE ENOUGH TO PRODUCE 2-3.5" SNOWFALL AMOUNTS
AND LIKELY SCATTERED HIGHER AMOUNTS WITHIN THE ADVISORY AREA.
RADAR ECHOES ARE ON THE UPWARD TREND ACROSS CENTRAL IA WITHIN THE
WARM AIR ADVECTION WING OF THE SHORT WAVE SEEN ON WATER VAPOR
PROGRESSING EAST SOUTHEAST. THIS WAVE WILL TURN MORE EAST ALONG A
WELL-DEFINED 850-600MB BAROCLINIC ZONE SEEN ON THIS EVES UPPER
AIR DATA. HAVE ALREADY NOTED 3/4SM VISIBILITY IN IA...LIKELY
ASSOCIATED WITH ONE HALF TO ONE INCH PER HOUR TYPE RATES. WITH
CLIPPER SYSTEMS IT SEEMS THAT THE LOWEST VISIBILITY CAN OFTEN BE
EXTRAPOLATED OUT ALONG THE PATH GIVEN THE WAVE MAINTAINS ITS
INTENSITY. THE RAP CONTINUES TO SHOW A FAIRLY QUICK PROGRESSION
OF THE LEADING EDGE OF SNOW OVER MUCH OF THE FORECAST AREA BETWEEN
12AM-3AM...SO DID NOT GET FANCY WITH TRYING TO ADJUST THE ADVISORY
START TIME. TEMPORARY WEST-TO-EAST BANDED SNOW OVERNIGHT WOULD
SEEM PROBABLE IN NORTH CENTRAL IL...MAYBE INTO THE CHICAGO
METRO...ALONG THE BAROCLINIC ZONE AND FAIRLY WELL-DEFINED
MOISTURE CONVERGENCE. CONVECTIVE ALLOWING/HIGH RES GUIDANCE
INDICATES HIGHER REFLECTIVITY AS WELL IN THE 3-8 AM PERIOD. SNOW
LOOKS TO LINGER OVER CHICAGO THROUGH THE END OF THE ADVISORY TIME.
FORECAST SOUNDINGS CONTINUE TO INDICATE A VERY DEEP DENDRITIC
GROWTH AREA WITH NOT OVERLY HIGH WINDS BELOW THE CLOUD BASE FOR
FRAGMENTING. EVEN THE 00Z DVN SOUNDING HAD THE WET BULB
TEMPERATURE BASICALLY WITHIN THE DENDRITIC GROWTH AREA ALL THE WAY
TO ~10000 FT! THIS SHOULD ALLOW FOR GOOD EFFICIENCY (20:1) OF
MEAGER PWAT VALUES UNDER 0.2 INCH AND MIXING RATIOS IN THE CLOUD
LAYER OF 1-1.5 G/KG. SO WE CONTINUE A LITTLE HIGHER THAT MOST
GUIDANCE FOR SNOWFALL AMOUNTS.
THE MOST PROBABLE TIMING FOR HEAVIEST SNOWFALL RATES IN ROCKFORD
IS 2-6 AM AND CHICAGO IS 4-8 AM. TEMPERATURES SHOULD CONTINUE TO
INCH UP PRIOR TO THE SNOWFALL...AND THEN HOLD STEADY IN THE MID-
UPPER TEENS DURING THE SNOW.
MTF
//PREV DISCUSSION...
250 PM...FORECAST CONCERNS INCLUDE ACCUMULATING SNOW TONIGHT INTO
WEDNESDAY MORNING...VERY COLD TEMPERATURES/WIND CHILLS WEDNESDAY
NIGHT AND ANOTHER POSSIBLE ACCUMULATING SNOW EVENT LATE FRIDAY
NIGHT INTO SATURDAY.
TEMPERATURES HAVE REBOUNDED QUITE A BIT FROM THIS MORNING/S SUB
ZERO READINGS WITH MANY AREAS IN THE LOWER/MID 20S. AS GUSTY WINDS
DIMINISH LATE THIS AFTERNOON INTO THIS EVENING...EXPECT TEMPS TO
STEADILY DROP INTO THE LOWER/MID TEENS AND THEN BECOME STEADY BY
LATE EVENING AND BEGIN RISING OVERNIGHT...POSSIBLY INTO THE LOWER
20S BY DAYBREAK.
A WEAK CLIPPER SYSTEM WILL MOVE ACROSS IOWA THIS EVENING AND THEN
ACROSS NORTHERN IL OVERNIGHT AND INTO NORTHWEST INDIANA WEDNESDAY
MORNING. FAIRLY GOOD AGREEMENT AMONG THE MODELS WITH A BAND OF
SNOW SPREADING INTO THE WESTERN CWA AROUND/SHORTLY AFTER MIDNIGHT
AND THEN ACROSS THE REST OF THE AREA DURING THE EARLY MORNING
HOURS...BEFORE SUNRISE. WHILE QPF AMOUNTS MAY ONLY RANGE IN THE
0.15 INCH RANGE...THE AIRMASS IS QUITE COLD AND EXPECT SNOW/WATER
RATIOS IN THE 18:1 TO 20:1 RANGE. THUS THE SNOW SHOULD BE QUITE
DRY AND FLUFFY. HAVE BUMPED QPF AMOUNTS AND SNOWFALL AMOUNTS UP
SLIGHTLY...GENERALLY IN THE 2.5 TO 3 INCH RANGE ALONG AND NORTH OF
INTERSTATE 80. AMOUNTS WILL QUICKLY TAPER OFF INTO THE SOUTHERN
THIRD OF THE CWA. THIS LOW BEGINS TO FILL SOME BY WEDNESDAY
MORNING AND AMOUNTS MAY BE HIGHER WESTERN AREAS THEN EASTERN
AREAS. THE ONE CONCERNING FACTOR IS THE GROWTH ZONE OF -10C TO
-14C WHICH BASED OF THE FORECAST SOUNDINGS COULD BE 150MB TO EVEN
200MB DEEP. THIS COULD ALLOW FOR SOME EFFICIENT SNOW DEVELOPMENT
ALONG WITH LARGE FLAKES...WHICH WOULD ALLOW FOR EVEN HIGHER
SNOWFALL AMOUNTS. THIS COULD ALSO LEAD TO SNOWFALL RATES
APPROACHING AN INCH AN HOUR FOR AT LEAST A SHORT TIME. WITH ALL
THIS IN MIND...WILL BE EXTENDING THE SNOW ADVISORY NORTH TO
INCLUDE THE FOUR NORTHERN COUNTIES AND MENTIONING STORM TOTAL
SNOWFALL AMOUNTS OF 2 TO 4 INCHES...WITH SOME UNCERTAINTY
REGARDING HOW WIDESPREAD THE 3 TO 4 INCH AMOUNTS MAY MATERIALIZE.
THE SNOW WILL TAPER OFF QUICKLY FROM WEST TO EAST AFTER SUNRISE
WITH NORTHWEST WINDS INCREASING AS THE SNOW ENDS AND THEN
REMAINING GUSTY INTO THE AFTERNOON. WIND GUSTS INTO THE 20-25 MPH
RANGE LOOK REASONABLE WHICH MAY CAUSE SOME BLOWING AND DRIFTING
SNOW BUT WILL MAINTAIN CURRENT ADVISORY EXPIRATION TIME OF 16Z
WEDNESDAY FOR NOW.
HIGH TEMPS WEDNESDAY WILL BE REACHED IN THE MORNING WITH STEADILY
FALLING TEMPS THROUGH THE AFTERNOON INTO WEDNESDAY NIGHT...WHICH
IS SHAPING UP TO BE VERY SIMILAR TO THIS MORNING. TEMPERATURES
WILL DIVE IN THE EVENING AND THEN BEGIN TO STEADY OVERNIGHT AND
POSSIBLY BEGIN TO RISE BY THURSDAY MORNING AS CLOUD COVER AND WEAK
WARM ADVECTION MOVE ACROSS THE REGION. BUT WITH A FRESH SNOW COVER
AND CLEARING SKIES...TEMPS SHOULD FALL BELOW ZERO JUST ABOUT
EVERYWHERE WITH THE USUAL COLD SPOTS PERHAPS INTO THE -10 RANGE.
THIS COMBINED WITH WESTERLY WINDS TURNING SOUTHWESTERLY...BUT IN
THE 10 MPH RANGE WILL PRODUCE WIND CHILLS FROM -15 TO -25 WITH
SOME LOCALLY LOWER VALUES. IF THESE TRENDS CONTINUE A WIND CHILL
ADVISORY MAY BE NEEDED DURING THIS TIME PERIOD.
TEMPS MODERATE SLIGHTLY THURSDAY INTO FRIDAY...THOUGH STILL BELOW
NORMAL. A COLD FRONT WILL SAG SOUTH ACROSS THE LAKES REGION
THURSDAY NIGHT AND FRIDAY...REACHING NORTHERN IL FRIDAY AFTERNOON.
MEANWHILE...LOW PRESSURE OVER THE SOUTHERN PLAINS LIFTS NORTHEAST
ACROSS THE OHIO VALLEY SATURDAY AND TO THE EASTERN LAKES BY SUNDAY
MORNING. A PROLONGED PERIOD OF LIGHT TO MODERATE SNOW WILL LIKELY
BEGIN FRIDAY NIGHT AND CONTINUE THROUGH MUCH OF SATURDAY WITH SOME
DIFFERENCES REGARDING THE CORRIDOR OF HEAVIEST QPF. BUT WITH
AMOUNTS IN THE 0.3 TO 0.5 RANGE...SEVERAL INCHES OF SNOW WILL BE
POSSIBLE. BUT WITH WARMER TEMPERATURES...PERHAPS NEAR FREEZING ON
SATURDAY...SNOW RATIOS SHOULD BE CLOSER TO 10:1 WITH A HEAVIER/WET
SNOW MOST LIKELY.
ANOTHER COLD DUMP SATURDAY NIGHT INTO SUNDAY. AND WHILE THE
STRENGTH OF COLD AIR IS STILL A BIT UNCERTAIN HAVE LOWERED TEMPS
SATURDAY NIGHT AND SUNDAY AND IF THIS MORNING AND WEDNESDAY NIGHT
ARE GOOD INDICATORS...TEMPS COULD BE SIGNIFICANTLY COLDER THAN
CURRENTLY ADVERTISED. CMS
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 06Z...
* MODERATE SNOWFALL OVERSPREADING THE TERMINALS LATE THIS EVENING
AND EARLY OVERNIGHT REDUCING VSBY TO IFR OR LOWER AND RESULTING
IN 2 TO 4 INCHES OF SNOW ACCUMULATION.
BMD
//DISCUSSION...UPDATED 06Z...
WINTER SYSTEM IS BRINGING AREA OF SNOW OVER IOWA LATE THIS
EVENING...AND WILL BE SPREADING EAST ACROSS NORTHERN ILLINOIS OVER
THE NEXT FEW HOURS. EXPECT VSBY TO FAIRLY QUICKLY DROP TO 1-2SM AS
THE SNOW BEGINS. THE BEST FORCING AND HEAVIEST SNOWFALL IS EXPECTED
TO BETWEEN ROUGHLY 8Z AND 12Z THIS EVENING WHERE VSBY MAY FALL UNDER
A MILE. QUITE A BIT A VARIABILITY IN CIGS UPSTREAM...BUT SHOULD
MAINLY BE IN THE 015-020 RANGE WITH TEMPO LOWER POSSIBLY IFR CIGS AT
TIMES. SNOW WILL BEGIN TO LET UP AROUND DAYBREAK WEDNESDAY MORNING
WHEN 2 TO 4 INCHES OF SNOW IS EXPECTED TO HAVE FALLEN. NORTHWEST
WINDS WITH GUSTS TO AROUND 20 KT ARE EXPECTED FROM MID MORNING
THROUGH MID AFTERNOON...THEN SHOULD EASE AND BEGIN TO BACK TO TO
WEST WEDNESDAY EVENING AS HIGH PRESSURE BUILDS DOWNSTATE.
BMD
//ORD AND MDW CONFIDENCE...UPDATED 06Z...
* MEDIUM-HIGH CONFIDENCE IN SNOWFALL INTENSITY AND TIMING.
* MEDIUM-HIGH CONFIDENCE IN VSBY TRENDS.
* MEDIUM CONFIDENCE IN CIG TRENDS...LOWER CONFIDENCE IN TIMING
IMPROVEMENT TO VFR MIDDAY WEDNESDAY.
BMD
//OUTLOOK FOR ORD/MDW FOR 12Z THURSDAY-12Z TUESDAY...UPDATED 00Z...
THURSDAY...VFR.
FRIDAY...SNOW ESPECIALLY OVERNIGHT.
SATURDAY...SNOW DURING THE DAY...TAPERING OFF AT NIGHT. MVFR OR
LOWER PSBL.
SUNDAY...CHANCE OF SNOW EARLY WITH CONDITIONS IMPROVING TO VFR
THROUGH THE DAY.
MONDAY...CHANCE OF SNOW...VFR.
JEE
&&
.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 MICHIGAN 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...ILZ003-ILZ004-ILZ005-ILZ006-ILZ008-
ILZ010-ILZ011-ILZ012-ILZ013-ILZ014-ILZ019-ILZ020-ILZ021-
ILZ022 UNTIL 10 AM WEDNESDAY.
IN...WINTER WEATHER ADVISORY...INZ001-INZ002 UNTIL 10 AM WEDNESDAY.
LM...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 GOODLAND KS
956 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 06Z TAFS THROUGH 06Z WEDNESDAY NIGHT)
ISSUED AT 955 PM MST TUE DEC 10 2013
VFR CONDITIONS ARE LIKELY THROUGH THE ENTIRE 24 FORECAST PERIOD.
POST-FRONTAL NORTHERLY WINDS AT AROUND 10-12 KNOTS SHOULD
DECREASE GRADUALLY OVERNIGHT. BY EARLY MORNING...SURFACE HIGH
PRESSURE MOVES SOUTHEASTWARD JUST TO THE EAST OF BOTH TERMINALS
RESULTING IN LIGHT WINDS. BY MID DAY A SOUTHWESTERLY WIND WILL
STRENGTHEN...POSSIBLY GUSTING TO NEAR 20 KNOTS DURING THE
AFTERNOON.
&&
.GLD WATCHES/WARNINGS/ADVISORIES...
KS...NONE.
CO...NONE.
NE...NONE.
&&
$$
SHORT TERM...DR
LONG TERM...024
AVIATION...BRB
AREA FORECAST DISCUSSION
NWS GRAND RAPIDS MI
327 AM EST WED DEC 11 2013
.SYNOPSIS...
ISSUED AT 327 AM EST WED DEC 11 2013
COLD AND SNOWY WEATHER WILL CONTINUE THROUGH THE REST OF THE WEEK
AND WEEKEND. A BURST OF HEAVIER SNOW IS ON THE WAY TO AREAS NEAR TO
MAINLY SOUTH OF INTERSTATE 96 FROM AROUND DAYBREAK THROUGH THE REST
OF THE MORNING INTO THE EARLY TO MID AFTERNOON HOURS. ANOTHER BURST
OF HEAVIER LAKE EFFECT SNOW WILL OCCUR THURSDAY FROM HOLLAND
NORTHWARD AS WINDS BACK TO THE SOUTHWEST. LOW PRESSURE WILL BRING
MORE SNOW SATURDAY WITH SEVERAL MORE ROUNDS OF SNOW EXPECTED LATE IN
THE WEEKEND INTO EARLY NEXT WEEK.
&&
.SHORT TERM...(TODAY THROUGH FRIDAY AFTERNOON)
ISSUED AT 327 AM EST WED DEC 11 2013
A CONSENSUS OF HIGHER RESOLUTION SHORT RANGE GUIDANCE INCLUDING THE
RUC... HRRR AND 4KM WRF NMM ALL INDICATE THAT ANOTHER BURST OF
HEAVIER SNOW WILL DEVELOP NEAR TO MAINLY SOUTH OF INTERSTATE 96
DURING THE EARLY TO MID MORNING HOURS. THE HEAVIEST SNOW WILL LINGER
THROUGH AT LEAST EARLY AFTERNOON BEFORE TAPERING OFF. A COUPLE OF
UPPER LEVEL DISTURBANCES MOVING THROUGH LATER THIS MORNING INTO THE
AFTERNOON WILL ENHANCE THE SNOW WITH DEEP LOW TO MID LEVEL MOISTURE
IN PLACE THROUGH 18Z THIS AFTERNOON AND WITH H8 TEMPS WAY DOWN
AROUND -16 TO -18 C.
HEAVIEST SNOW FROM MID MORNING THROUGH EARLY TO MID AFTERNOON WILL
FALL MAINLY SOUTH OF I-96 WITH ABOUT 3 TO 5 INCHES OF SNOW EXPECTED
DOWN AROUND HASTINGS... ALLEGAN... SOUTH HAVEN AND KALAMAZOO. A
BUKFIT X-SECTION FOR SOUTH HAVEN SHOWS ABOUT 10 MICROBARS/SEC OF
LIFT LATE THIS MORNING WITH INVERSION HEIGHTS UP AROUND 8-9 KFT. OUR
ONGOING WINTER WEATHER HEADLINES LOOK EXCELLENT AND WILL REMAIN
UNCHANGED.
WNW TO WEST FLOW LES WILL CONTINUE TONIGHT WITH SUFFICIENT MOISTURE
STILL IN PLACE AND H8 TEMPS STILL DOWN AROUND -16 TO -18 C. THEN
WINDS WILL BACK TO THE WSW TO SW THURSDAY FAVORING AREAS FROM AROUND
BIV NORTHWARD OVER OUR NW FCST AREA TO RECEIVE SEVERAL INCHES OF
LAKE EFFECT. LAKE EFFECT SNOW SHOWERS SHOULD FINALLY WIND DOWN A BIT
THURSDAY NIGHT AS H8 TEMPS SLOWLY MODERATE. ONLY A SMALL CHANCE FOR
LIGHT SNOW SHOWERS FRIDAY SINCE BY THEN SFC WINDS SHOULD BECOME
EASTERLY.
.LONG TERM...(FRIDAY NIGHT THROUGH TUESDAY)
ISSUED AT 327 AM EST WED DEC 11 2013
LIKELY POPS STILL LOOKS GOOD FOR SATURDAY AS THE 00Z GUIDANCE HAS
MAINTAINED CONTINUITY WITH THE LOW COMING OUT OF THE SOUTHERN
PLAINS. MID LEVEL F-GEN COULD BE STRONG ENOUGH TO PRODUCE MESOSCALE
BANDS OF LIGHT TO MODERATE SNOW FOR SEVERAL HOURS SATURDAY AFTERNOON
AND EVENING ACROSS CENTRAL AND SOUTHERN LOWER MICHIGAN.
THE LOW MOVES EAST SATURDAY NIGHT...BUT LOWER MICHIGAN REMAINS IN
THE TROWAL INTO SUNDAY. SO THE SNOW WILL LESSEN IN INTENSITY BUT NOT
END AS AN ARCTIC FRONT PROVIDES SFC CONVERGENCE INTO SUNDAY NIGHT.
SFC RIDGING SHOULD BUILD IN LATE SUNDAY NIGHT THEN RETURN FLOW
FOLLOWS FOR MONDAY IN ADVANCE OF NEXT CLIPPER. SNOW TAPERS OFF
MONDAY BEFORE WARM ADVECTION SNOWS BREAK OUT MONDAY NIGHT FOLLOWED
BY LAKE ENHANCED SNOW SHOWERS FOR TUESDAY.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z WEDNESDAY NIGHT)
ISSUED AT 1145 PM EST TUE DEC 10 2013
SNOW WILL INCREASE IN COVERAGE AND INTENSITY LATE TONIGHT AS A
WAVE OF LOW PRESSURE APPROACHES. MANY SITES ARE TO GO DOWN TO IFR
OR LOWER DUE TO LOW CEILINGS AND VISIBILITIES. DURING THE LATE
MORNING AND THROUGH THE AFTERNOON...THE SNOW BANDS WILL SHIFT
SOUTH AS THE WINDS VEER WITH TIME...BECOMING NORTHWEST BY LATE IN
THE DAY. A TREND TOWARD VFR IS EXPECTED.
&&
.MARINE...
ISSUED AT 327 AM EST WED DEC 11 2013
A SMALL CRAFT ADVISORY HAS BEEN ISSUED FOR TODAY THROUGH EARLY
THURSDAY EVENING AS BRISK WEST NORTHWEST WINDS WILL RESULT IN WAVE
HEIGHTS GENERALLY AROUND 4 TO 7 FEET TODAY AND TONIGHT. WINDS
THURSDAY WILL BACK TO THE SOUTHWEST AT 15 TO 25 KNOTS RESULTING IN
CONTINUED SIGNIFICANT WAVE ACTION.
&&
.HYDROLOGY...
ISSUED AT 327 AM EST WED DEC 11 2013
TEMPERATURES WILL REMAIN WELL BELOW NORMAL THROUGH THE REST OF THE
WEEK AND WEEKEND ALONG WITH SEVERAL ROUNDS OF SNOW SHOWERS. THIS
COMBINATION OF SNOW AND COLD TEMPERATURES WILL RESULT IN POTENTIAL
FOR ICE JAM FORMATION. SO WE WILL CONTINUE TO MONITOR RIVER LEVELS
CLOSELY.
&&
.GRR WATCHES/WARNINGS/ADVISORIES...
MI...WINTER WEATHER ADVISORY UNTIL 5 PM EST TODAY FOR MIZ037-043-
050-056-057-064-071.
WINTER WEATHER ADVISORY UNTIL 5 PM EST TODAY FOR MIZ065-066-
072-073.
LM...SMALL CRAFT ADVISORY UNTIL 7 PM EST THURSDAY FOR LMZ844>849.
&&
$$
SYNOPSIS...LAURENS
SHORT TERM...LAURENS
LONG TERM...OSTUNO
AVIATION...MJS
HYDROLOGY...LAURENS
MARINE...LAURENS
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
1227 AM EST WED DEC 11 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 06Z TAFS THROUGH 06Z WEDNESDAY NIGHT)
ISSUED AT 1225 AM EST WED DEC 11 2013
KIWD...EXPECT MVFR CONDITIONS TO LAST THROUGH WED EVENING WITH LAKE
EFFECT SNOW SHOWERS CONTINUING. AS WINDS BECOME MORE SW BY WED
EVENING...LAKE CLOUDS WILL PUSH NORTH AND CONDITIONS WILL BE VFR.
KCMX...EXPECT IFR TO LIFR CONDITIONS THROUGH THE FORECAST PERIOD
WITH LAKE EFFECT SNOW BANDS PASSING THROUGH. WITH GUSTY WINDS...THE
BLOWING SNOW WILL BE THE MAIN FACTOR IN THE LOWER VISIBILITIES.
KSAW...VFR CONDITIONS WILL CONTINUE THRU THE FORECAST PERIOD.
DOWNSLOPE NATURE OF THE W WIND AND RELATIVE DRYNESS OF THE AIRMASS
SHOULD MAINTAIN THE VFR WX AT THIS SITE EVEN IF SOME FLURRIES MAKE
IT INTO THE AREA WED MORNING.
&&
.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 THIS AFTERNOON FOR
MIZ004-084.
LAKE EFFECT SNOW ADVISORY UNTIL 7 PM EST THIS EVENING FOR MIZ085.
LAKE EFFECT SNOW ADVISORY UNTIL MIDNIGHT EST TONIGHT FOR MIZ002-
003-006.
LAKE EFFECT SNOW ADVISORY UNTIL 7 AM EST THIS MORNING 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 UNTIL 11 AM CST WEDNESDAY FOR MIZ010.
LAKE SUPERIOR...
HEAVY FREEZING SPRAY WARNING UNTIL 6 PM EST THIS EVENING FOR
LSZ266.
HEAVY FREEZING SPRAY WARNING UNTIL 6 AM EST /5 AM CST/ THURSDAY
FOR LSZ162-240>245-248>251-263>265.
LAKE MICHIGAN...
HEAVY FREEZING SPRAY WARNING UNTIL 6 AM EST EARLY THIS MORNING
FOR LMZ221-248-250.
&&
$$
SHORT TERM...ROLFSON
LONG TERM...KF
AVIATION...07
MARINE...KF
AREA FORECAST DISCUSSION...UPDATED
NWS NORTH PLATTE NE
1130 PM CST TUE DEC 10 2013
.SYNOPSIS...
ISSUED AT 305 PM CST TUE DEC 10 2013
H5 ANALYSIS THIS MORNING HAS BROAD NORTHWESTERLY FLOW
ACROSS THE WESTERN HALF OF THE CONUS WITH DEEP LOW PRESSURE OVER SRN
HUDSON BAY. AT THE SURFACE...A COLD FRONT EXTENDED FROM NERN WYOMING
INTO NERN SD. FURTHER SOUTH ACROSS WESTERN AND NORTH CENTRAL
NEBRASKA...WESTERLY FLOW HAS DEVELOPED THIS AFTERNOON WITH
TEMPERATURES REACHING THE 20S AND LOWER 30S.
&&
.UPDATE...
ISSUED AT 614 PM CST TUE DEC 10 2013
THE ECM...RAP...GEM REG AND HRRR MODELS SHOW WIND CHILL ADVISORY
CONDITIONS BY MORNING ACROSS THE NORTHEAST FROM AINWSORTH AND
ONEILL NORTH. A NEW FORECAST IS OUT FOR THESE CONDITIONS.
OTHERWISE THE REST OF THE FORECAST IS ON TRACK WITH THE LEADING
EDGE OF THE ARCTIC AIR ENTERING SHERIDAN COUNTY AND SETTING OFF
SNOW SHOWERS. LOW LEVEL LAPSE RATES ARE VERY STEEP WITH ECHO TOPS
LESS THAN 10KFT.
&&
.SHORT TERM...(THIS EVENING THROUGH WEDNESDAY)
ISSUED AT 305 PM CST TUE DEC 10 2013
AN ARCTIC COLD FRONT WILL MOVE SOUTHEAST ACROSS THE AREA
TONIGHT...WITH A FEW SNOW SHOWERS POSSIBLE ACROSS NORTHERN NEBRASKA
BEHIND THE FRONT. FLURRIES ARE POSSIBLE FARTHER SOUTH AS
WELL...WITH A PERIOD OF WEAK LIFT THROUGH A SATURATED DENDRITIC
LAYER BEHIND THE FRONT. OTHERWISE...WINDS DIMINISH AS HIGH PRESSURE
SETTLES INTO NORTHERN NEBRASKA LATE TONIGHT. THIS WILL ALLOW FOR
LOWS TO DROP TO NEAR ZERO OR JUST BELOW AS SKIES CLEAR LATE.
FARTHER SOUTH WINDS REMAIN UP THROUGH THE NIGHT...AND THIS WILL
HELP KEEP LOWS SOMEWHAT WARMER.
HIGH PRESSURE WILL QUICKLY MOVE SOUTHEAST OF THE AREA
WEDNESDAY...WITH WARMING SOUTHWEST WINDS DEVELOPING BY WEDNESDAY
AFTERNOON. HAVE PUSHED HIGHS UP INTO THE LOWER 30S ACROSS
SOUTHWEST NEBRASKA...BUT ONLY NEAR 20 DEGREES ACROSS EASTERN
PORTIONS OF NORTH CENTRAL NEBRASKA WHERE THE ARCTIC AIR WILL BE
DEEPER.
.LONG TERM...(WEDNESDAY NIGHT THROUGH TUESDAY)
ISSUED AT 305 PM CST TUE DEC 10 2013
IN THE MID
RANGE...TEMPERATURES ARE THE MAIN FORECAST CHALLENGE. FOR WEDNESDAY
NIGHT...LOOK FOR WINDS TO DECREASE BY LATE EVENING AS A WARM FRONT
TRACKS EAST OF THE AREA. CLEAR SKIES AND LIGHT WINDS WILL ALLOW
TEMPS TO DIP INTO THE SINGLE DIGITS ACROSS THE FORECAST AREA.
INHERITED FORECAST HAD ALOT OF TEENS FOR LOWS WEDS NIGHT AND SCALED
THESE BACK TOWARD THE NEW GUIDANCE...WHICH TRENDED MUCH LOWER AS
WELL. ON THURSDAY...WARMER PACIFIC AIR WILL PUSH INTO THE CENTRAL
PLAINS WITH H85 TEMPS REACHING THE MIDDLE SINGLE DIGITS CELSIUS
ABOVE ZERO THURSDAY AFTERNOON. NORMALLY WITH GOOD MIXING...HIGHS
WOULD REACH THE UPPER 40S TO LOWER 50S. HOWEVER...WINDS ARE EXPECTED
TO BE FAIRLY LIGHT THURSDAY...A BY PRODUCT OF SNOW COVER AND ITS
IMPACT ON MIXING. BUFKIT SOUNDINGS FOR BOTH LBF AND VTN ARE NOT
INDICATIVE OF MIXING EITHER. GUIDANCE HIGHS THURSDAY FOR VALENTINE
WERE IN THE MID 40S WITH THIS MORNINGS FCST. THIS SEEMS WAY TOO HIGH
WITH 6+ INCHES OF SNOW EXPECTED TO BE ON THE GROUND ACROSS NORTH
CENTRAL NEBRASKA. HAVE OPTED FOR HIGH IN THE LOWER 40S SOUTHWEST TO
LOWER 30S IN THE NORTHEAST AND PORTIONS OF THE NORTH CENTRAL
FORECAST AREA. LOWS THURSDAY NIGHT WILL BE SLIGHTLY HIGHER THAN
WEDNESDAY NIGHTS MIN TEMPS DUE TO INCREASED HIGH LEVEL
CLOUDINESS...AND THE DEVELOPMENT OF LIGHT WINDS IN ADVANCE OF THE
NEXT ARCTIC COLD FRONT WHICH WILL ARRIVE SOMETIME FRIDAY MORNING OR
AFTERNOON. I DID GO AHEAD AND TREND DOWN HIGHS FRIDAY ACROSS THE
NORTHERN CWA BASED ON A SLIGHTLY FASTER FRONTAL TIMING IE. GFS
SOLUTION...WHICH HAS BEEN MORE CONSISTENT. HIGHS FRIDAY WILL RANGE
FROM THE MID 20S IN THE NORTHEAST...TO AROUND 40 IN THE
SOUTHWEST.
FRIDAY NIGHT THROUGH TUESDAY...BROAD NORTHWESTERLY FLOW WILL
CONTINUE ACROSS THE CENTRAL AND NORTHERN PLAINS FOR THE EXTENDED
PERIOD. WITH THE NORTHWESTERLY FLOW IN PLACE ARCTIC COLD AIR WILL
BACK INTO THE FORECAST AREA SATURDAY...RETREATING EASTWARD LATE
SUNDAY OR MONDAY. ATTM...THE GFS AND ECMWF SOLUTIONS ARE AT ODDS
WITH HOW FAST THE FRONT PUSHES EAST OUT OF THE AREA WITH THE GFS
BEING SLOWER. ON MONDAY INTO TUESDAY...THE GFS ADVERTISES A NICE
WARMUP WHILE THE ECMWF USHERS IN ANOTHER SHOT OF ARCTIC AIR. FOR
NOW...WILL COMPROMISE BETWEEN SOLUTIONS AND LEAVE THE FORECAST DRY
AS THE NORTHWESTERLY FLOW FAVORS IT.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z WEDNESDAY NIGHT)
ISSUED AT 1129 PM CST TUE DEC 10 2013
MVFR CIGS BETWEEN KVTN AND KTIF WILL DROP SOUTH THROUGH KLBF
OVERNIGHT. THE MODELS THEN SUGGEST THIS MOISTURE WILL BECOME
TRAPPED AND PRODUCE IFR/LIFR CIGS TOWARD MORNING BUT THIS IS
UNCERTAIN GIVEN THE VERTICAL MIXING THAT COULD DEVELOP AFTER
SUNRISE.
THE FCST FOLLOWS THE MODEL SOLN AT KLBF BUT KEEPS KVTN IN VFR
DURING THE MORNING. IF THE MVFR/IFR CIGS DEVELOP AT KLBF AFTER
NEAR OR AFTER SUNRISE THEN THEY WOULD LIKELY GET LIFTED EAST
THROUGH KANW/KONL/KBBW DURING THE LATE MORNING AND AFTN AS A
DEVELOPING WARM FRONT.
&&
.LBF WATCHES/WARNINGS/ADVISORIES...
WIND CHILL ADVISORY UNTIL 11 AM CST WEDNESDAY FOR NEZ006>010.
&&
$$
UPDATE...CDC
SYNOPSIS...CLB
SHORT TERM...TAYLOR
LONG TERM...CLB
AVIATION...CDC
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
334 AM CST WED DEC 11 2013
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 334 AM CST WED DEC 11 2013
MAIN FORECAST CONCERNS ARE ON WIND CHILLS THROUGH TONIGHT AND
PRECIPITATION CHANCES TONIGHT.
CURRENTLY AS OF 09Z...WATER VAPOR LOOP AND RAP 500MB HEIGHT ANALYSIS
SHOWED UPPER RIDGING NEAR THE WEST COAST OF THE U.S....BROAD
TROUGHING OVER THE EAST HALF OF CANADA...AND A SHORTWAVE TROUGH
STRETCHING FROM MN INTO NEBRASKA. AHEAD OF THIS SHORTWAVE TROUGH...A
FRONTOGENESIS BAND OF SNOW ENCOMPASSED MUCH OF EASTERN IOWA INTO
SOUTHERN WI...WHILE CLOUDS COVERED MUCH OF THE FORECAST AREA.
HOWEVER...CLEARING ASSOCIATED WITH SUBSIDENCE IN THE TROUGH WAS
QUICKLY APPROACHING THE FORECAST AREA FROM CENTRAL MN. THIS CLEARING
WAS RIGHT BEHIND A COLD FRONT...WHICH ALSO REPRESENTS AN ARCTIC
AIRMASS POISED TO COME INTO THE AREA TODAY. READINGS ARE BELOW ZERO
FROM NORTH DAKOTA INTO CENTRAL MN...AND IN MANY SPOTS TEENS BELOW
ZERO. 850MB STANDARDIZED TEMPERATURE ANOMALIES ASSOCIATED WITH THIS
ARCTIC AIRMASS ARE 2 BELOW NORMAL. ACCOMPANYING THE ARCTIC AIR ARE
SOME BRISK NORTHWEST WINDS...PARTICULARLY WITH THE ISALLOBARIC PUSH
RIGHT BEHIND THE COLD FRONT. THESE WINDS ARE KNOCKING WIND CHILLS
DOWN TO 20 TO 35 BELOW FROM CENTRAL MN THROUGH NORTHERN WI
NORTHWESTWARD.
THE COLD AIR AND CLEARING SEEN OVER CENTRAL MN WILL RUSH INTO THE
FORECAST AREA QUICKLY THIS MORNING...ASSOCIATED WITH THE COLD
FRONTAL AND SHORTWAVE TROUGH PASSAGE. WINDS SHOULD STAY BRISK ALL
DAY AS A SURFACE OVER THE WESTERN DAKOTAS ENDS UP SLIDING WELL TO
OUR SOUTH...INTO NORTHERN MO BY 00Z. THE STRONGEST WINDS ARE LIKELY
THIS MORNING AS PRESSURES RISE RAPIDLY. TEMPERATURES LOOK TO FALL
THROUGH MID MORNING...MAY GET A LITTLE BUMP UP EARLY THIS AFTERNOON
WITH DAYTIME HEATING...AND FALL YET AGAIN ONCE THE SUN STARTS GOING
DOWN. THUS...ITS GOING TO BE TOUGH TO WARM TODAY. HIGHS IN THE
SINGLE DIGITS ABOVE ZERO APPEARS TO BE ALL WE CAN GET...WITH
LOCATIONS NORTH OF HIGHWAY 10 NOT EVEN REACHING ZERO. FACTOR IN THE
WIND AND MUCH OF THE AREA WILL SEE WIND CHILLS REACHING 20 BELOW
ZERO OR COLDER AT TIMES...ESPECIALLY THIS MORNING AND LATE TODAY.
REGARDING HAZARDS...LIKELY SOMETIME BETWEEN 12-13Z TODAY WE CAN
TRANSITION THE WINTER WEATHER ADVISORY OVER TO A WIND CHILL
ADVISORY IN NORTHEAST IOWA.
THIS SHOT OF ARCTIC AIR APPEARS TO BE SHORT-LIVED...HOWEVER. A
SHORTWAVE SEEN OVER ALBERTA IS PROGGED BY MODELS TO DROP DOWN
THROUGH CENTRAL MN AND WI BETWEEN 06-12Z TONIGHT. THE APPROACH OF
THE SHORTWAVE HELPS TO SWING WINDS AROUND TO THE SOUTHWEST...AND
SPREAD SOME MID/HIGH CLOUDS INTO THE AREA RESULTING FROM DPVA AND
ISENTROPIC LIFT. SO AFTER SOME COOLING FROM RADIATIONAL PROCESSES IN
THE EVENING...ADVECTIVE PROCESSES WILL HELP TEMPERATURES CLIMB
THEREAFTER. GIVEN THE COLD EVENING...EXTENDED THE WIND CHILL
ADVISORY THROUGH 12Z THU FOR SOUTHEAST MN INTO SOUTHWEST AND
CENTRAL WI. EXPANDED BOTH IN TIME AND AREA THE ADVISORY TO HELP
BLEND WITH MKX AND DVN OFFICES. THE NEXT QUESTION IS IF ANY SNOW
CAN FALL WITH THE SHORTWAVE. THE 11.00Z GFS/CANADIAN/ECMWF ALL
PRODUCE A BAND OF LIGHT QPF...WITH SOUNDINGS SUGGESTING THE
FORCING IS MOSTLY CO- LOCATED WITH THE DENDRITIC GROWTH ZONE. THE
AFOREMENTIONED MODELS ALL SUGGEST A QUICK MOVING BAND...LIMITING
ACCUMULATIONS...BUT A FEW TENTHS SEEM REASONABLE. HAVE RAISED
PRECIPITATION CHANCES TOWARDS 60. NAM IS THE ONLY MODEL NOT
SHOWING ANY PRECIPITATION...BUT EVEN IT HAS INDICATIONS OF THE
FORCING.
.LONG TERM...(THURSDAY THROUGH TUESDAY)
ISSUED AT 334 AM CST WED DEC 11 2013
MAIN LONG TERM FORECAST CONCERNS ARE ON MINIMAL PRECIPITATION
CHANCES THROUGHOUT.
SOME DEAMPLIFICATION OF THE FLOW ACROSS THE NORTHERN U.S. IS PROGGED
TO OCCUR THURSDAY THROUGH FRIDAY IN RESPONSE TO A TROUGH DROPPING
DOWN THROUGH THE PACIFIC NORTHWEST. THE SWITCH TO A ZONAL FLOW
PATTERN IN THE NORTHERN STREAM APPEARS TO HAVE PLENTY OF MID/UPPER
LEVEL MOISTURE...WHICH IS GOING TO MANIFEST ITSELF IN A LOT OF
CLOUDS. PRECIPITATION CHANCES OVERALL LOOK PRETTY MINIMAL...
THOUGH...AS PLENTIFUL DRY LOW LEVEL AIR IS IN PLACE. ADDITIONALLY...
FORCING APPEARS RESTRICTED TO SOME WEAK MID LEVEL FRONTOGENESIS
STRETCHING FROM NORTHERN/CENTRAL MN INTO NORTHERN WI THU NIGHT AND
FRIDAY. THIS FORCING COULD SQUEEZE OUT SOME SNOW...BUT CONFIDENCE IS
ONLY HIGH ENOUGH FOR A 20 PERCENT CHANCE NORTH OF HIGHWAY 10.
REGARDING THAT AFOREMENTIONED FRONTOGENESIS...THIS WILL OCCUR BEHIND
A COLD FRONTAL PASSAGE PROGGED TO MOVE THROUGH THE AREA THU NIGHT.
SO AFTER A WARMER THURSDAY IN RESPONSE TO LOW LEVEL WARM
ADVECTION...TEMPERATURES HEAD BACK DOWN THU NIGHT...BUT NOT NEARLY
AS COLD AS IT HAS BEEN. DESPITE THE COLD ADVECTION...TEMPERATURES
FRIDAY SHOULD REBOUND CLOSE TO THURSDAYS HIGHS.
FOR FRIDAY NIGHT AND SATURDAY...THE FOCUS HAS BEEN ON A SHORTWAVE
TROUGH AND GENERAL SYSTEM COMING OUT OF THE CENTRAL PLAINS. THIS
SHORTWAVE TROUGH IS CURRENTLY AN UPPER LOW SITTING OFF THE FAR
SOUTHERN CALIFORNIA COAST. 11.00Z ECMWF/GFS/CANADIAN HAVE TRENDED
SLIGHTLY FARTHER SOUTHEAST WITH THIS SYSTEM...AND AS SUCH...THE
PRECIPITATION ALSO MOVED A LITTLE FARTHER AWAY. THERE STILL ARE
INDICATIONS THAT THE MID LEVEL FRONTOGENESIS SITTING OVER NORTHERN
WI ON FRIDAY WILL SLIDE SOUTH OVER THE REST OF THE AREA FRIDAY
NIGHT...POSSIBLY SQUEEZING OUT A LITTLE LIGHT SNOW.
THEREFORE...HAVE HAD TO MAINTAIN SOME 20-40 PERCENT
CHANCES...HIGHEST BETWEEN 06-12Z SATURDAY. CHANCES CONTINUE
THROUGH THE DAY SATURDAY AND INTO SATURDAY NIGHT...MORE IN
RESPONSE TO A POTENT SHORTWAVE TROUGH DROPPING DOWN FROM MANITOBA
INTO UPPER MICHIGAN.
FOR SUNDAY AND BEYOND...SUNDAY IS LOOKING CHILLY AS THE POTENT
TROUGH BRINGS DOWN A BRIEF SHOT OF ARCTIC AIR WITH IT ON ITS BACK
SIDE. 850MB TEMPS FALL TO -14 TO -20C AT 18Z SUNDAY PER 11.00Z
ECMWF...COLDEST OVER TAYLOR COUNTY. MAY GET CLOSE FOR NEEDING A WIND
CHILL ADVISORY SUNDAY MORNING. A WARM ADVECTION PATTERN THEN LOOKS
TO ENSUE FOR SUNDAY NIGHT INTO MONDAY AS YET ANOTHER DECENT
SHORTWAVE TROUGH TRACKS FROM MANITOBA INTO UPPER MICHIGAN. FOLLOWED
CONSENSUS AND INCLUDED 20 PERCENT CHANCES FOR MONDAY. TEMPERATURES
MAY REBOUND HIGHER TOO THAN CURRENTLY FORECAST...BUT GIVEN HOW FAR
OUT THIS PERIOD IS IN THE FORECAST...STAYED CLOSER TO A MODEL
CONSENSUS WITH HIGHS IN THE 15-20 RANGE.
FOR THOSE LOOKING FOR A WARM-UP...THE ECMWF CONTINUES TO HINT AT ONE
FOR THE MIDDLE TO END OF NEXT WEEK AS A DEEP TROUGH FORMS OVER THE
WESTERN U.S.. THE CFS HAS ALSO BEEN ADVERTISING ABOVE NORMAL
TEMPERATURES DURING THIS SAME TIME PERIOD.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z WEDNESDAY NIGHT)
ISSUED AT 1125 PM CST TUE DEC 10 2013
LATEST SHORT WAVE TROUGH IS MOVING THROUGH THE REGION QUICKLY LATE
THIS EVENING. LOWER VISIBILITIES AND CEILINGS REMAINING JUST SOUTH
OF FORECAST AREA BUT STILL SEEING MVFR CONDITIONS WITH LIGHT SNOW
FLYING FOR A FEW MORE HOURS. AS WAVE MOVES OUT OVERNIGHT...COLD
FRONT ON ITS HEELS WILL SCATTER CLOUDS OUT QUICKLY LEADING TO RETURN
TO VFR CONDITIONS BY DAYBREAK.
GUSTY NORTHWEST WINDS BEHIND FRONT EARLY THIS MORNING COULD KICK UP
A LITTLE BLOWING SNOW AT TIMES PRODUCING MINIMAL IMPACT TO AVIATION.
WINDS WILL SUBSIDE WEDNESDAY AFTERNOON AS SHORT TERM RIDGING BUILDS
IN AHEAD OF YET ANOTHER WAVE LATER WEDNESDAY NIGHT.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
WI...WINTER WEATHER ADVISORY UNTIL 9 AM CST THIS MORNING FOR WIZ054-
061.
WIND CHILL ADVISORY UNTIL 6 AM CST THURSDAY FOR WIZ032>034-
041>044.
WIND CHILL ADVISORY FROM 6 PM THIS EVENING TO 6 AM CST THURSDAY
FOR WIZ053-055.
WIND CHILL ADVISORY UNTIL 6 AM CST THURSDAY FOR WIZ017-029.
MN...WIND CHILL ADVISORY UNTIL 6 AM CST THURSDAY FOR MNZ079-086>088-
094>096.
IA...WINTER WEATHER ADVISORY UNTIL 9 AM CST THIS MORNING FOR
IAZ008>011-018-019-029-030.
&&
$$
SHORT TERM...AJ
LONG TERM...AJ
AVIATION...SHEA
AREA FORECAST DISCUSSION
NWS GREEN BAY WI
1045 PM CST TUE DEC 10 2013
UPDATED AVIATION PORTION FOR 06Z TAF 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 06Z TAF ISSUANCE
ISSUED AT 1045 PM CST TUE DEC 10 2013
ANOTHER IN A SERIES OF WEAK CLIPPER SYSTEMS WILL PASS OVER THE
SOUTH HALF THE STATE OVERNIGHT BEFORE DEPARTING SOUTHEAST
WISCONSIN WEDNESDAY MORNING. EXPECT MAINLY A PERIOD OF VFR CIGS
WITH SCATTERED MVFR CIGS DURING PASSAGE FOLLOWED BY ANOTHER SHOT
OF COLD ARCTIC AIR WITH GUSTY WEST WINDS FOR WEDNESDAY. DRIER AIR
WILL DIMINISH CLOUDS QUICKLY FROM WEST TO EAST FOR VFR CONDITIONS
FOR WEDNESDAY.
&&
.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 UNTIL 9 AM CST THURSDAY FOR WIZ005-010>012-
018-019-030-035-036.
&&
$$
SHORT TERM.....MPC
LONG TERM......KIECKBUSCH
AVIATION.......TDH
AREA FORECAST DISCUSSION
NWS GRAND RAPIDS MI
644 AM EST WED DEC 11 2013
LATEST UPDATE...
AVIATION
.SYNOPSIS...
ISSUED AT 327 AM EST WED DEC 11 2013
COLD AND SNOWY WEATHER WILL CONTINUE THROUGH THE REST OF THE WEEK
AND WEEKEND. A BURST OF HEAVIER SNOW IS ON THE WAY TO AREAS NEAR TO
MAINLY SOUTH OF INTERSTATE 96 FROM AROUND DAYBREAK THROUGH THE REST
OF THE MORNING INTO THE EARLY TO MID AFTERNOON HOURS. ANOTHER BURST
OF HEAVIER LAKE EFFECT SNOW WILL OCCUR THURSDAY FROM HOLLAND
NORTHWARD AS WINDS BACK TO THE SOUTHWEST. LOW PRESSURE WILL BRING
MORE SNOW SATURDAY WITH SEVERAL MORE ROUNDS OF SNOW EXPECTED LATE IN
THE WEEKEND INTO EARLY NEXT WEEK.
&&
.SHORT TERM...(TODAY THROUGH FRIDAY AFTERNOON)
ISSUED AT 327 AM EST WED DEC 11 2013
A CONSENSUS OF HIGHER RESOLUTION SHORT RANGE GUIDANCE INCLUDING THE
RUC... HRRR AND 4KM WRF NMM ALL INDICATE THAT ANOTHER BURST OF
HEAVIER SNOW WILL DEVELOP NEAR TO MAINLY SOUTH OF INTERSTATE 96
DURING THE EARLY TO MID MORNING HOURS. THE HEAVIEST SNOW WILL LINGER
THROUGH AT LEAST EARLY AFTERNOON BEFORE TAPERING OFF. A COUPLE OF
UPPER LEVEL DISTURBANCES MOVING THROUGH LATER THIS MORNING INTO THE
AFTERNOON WILL ENHANCE THE SNOW WITH DEEP LOW TO MID LEVEL MOISTURE
IN PLACE THROUGH 18Z THIS AFTERNOON AND WITH H8 TEMPS WAY DOWN
AROUND -16 TO -18 C.
HEAVIEST SNOW FROM MID MORNING THROUGH EARLY TO MID AFTERNOON WILL
FALL MAINLY SOUTH OF I-96 WITH ABOUT 3 TO 5 INCHES OF SNOW EXPECTED
DOWN AROUND HASTINGS... ALLEGAN... SOUTH HAVEN AND KALAMAZOO. A
BUKFIT X-SECTION FOR SOUTH HAVEN SHOWS ABOUT 10 MICROBARS/SEC OF
LIFT LATE THIS MORNING WITH INVERSION HEIGHTS UP AROUND 8-9 KFT. OUR
ONGOING WINTER WEATHER HEADLINES LOOK EXCELLENT AND WILL REMAIN
UNCHANGED.
WNW TO WEST FLOW LES WILL CONTINUE TONIGHT WITH SUFFICIENT MOISTURE
STILL IN PLACE AND H8 TEMPS STILL DOWN AROUND -16 TO -18 C. THEN
WINDS WILL BACK TO THE WSW TO SW THURSDAY FAVORING AREAS FROM AROUND
BIV NORTHWARD OVER OUR NW FCST AREA TO RECEIVE SEVERAL INCHES OF
LAKE EFFECT. LAKE EFFECT SNOW SHOWERS SHOULD FINALLY WIND DOWN A BIT
THURSDAY NIGHT AS H8 TEMPS SLOWLY MODERATE. ONLY A SMALL CHANCE FOR
LIGHT SNOW SHOWERS FRIDAY SINCE BY THEN SFC WINDS SHOULD BECOME
EASTERLY.
.LONG TERM...(FRIDAY NIGHT THROUGH TUESDAY)
ISSUED AT 327 AM EST WED DEC 11 2013
LIKELY POPS STILL LOOKS GOOD FOR SATURDAY AS THE 00Z GUIDANCE HAS
MAINTAINED CONTINUITY WITH THE LOW COMING OUT OF THE SOUTHERN
PLAINS. MID LEVEL F-GEN COULD BE STRONG ENOUGH TO PRODUCE MESOSCALE
BANDS OF LIGHT TO MODERATE SNOW FOR SEVERAL HOURS SATURDAY AFTERNOON
AND EVENING ACROSS CENTRAL AND SOUTHERN LOWER MICHIGAN.
THE LOW MOVES EAST SATURDAY NIGHT...BUT LOWER MICHIGAN REMAINS IN
THE TROWAL INTO SUNDAY. SO THE SNOW WILL LESSEN IN INTENSITY BUT NOT
END AS AN ARCTIC FRONT PROVIDES SFC CONVERGENCE INTO SUNDAY NIGHT.
SFC RIDGING SHOULD BUILD IN LATE SUNDAY NIGHT THEN RETURN FLOW
FOLLOWS FOR MONDAY IN ADVANCE OF NEXT CLIPPER. SNOW TAPERS OFF
MONDAY BEFORE WARM ADVECTION SNOWS BREAK OUT MONDAY NIGHT FOLLOWED
BY LAKE ENHANCED SNOW SHOWERS FOR TUESDAY.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z THURSDAY MORNING)
ISSUED AT 643 AM EST WED DEC 11 2013
MVFR AND IFR IN SNOW AND BLOWING SNOW THIS MORNING WILL IMPROVE TO
MVFR AND VFR BY 18Z FOR MOST PLACES. THE HEAVIER SNOW WILL BE
AROUND AZO WHERE IFR WILL BE PREVAILING MUCH OF THE MORNING. WINDS
WILL BE WEST AROUND 10 TO 15 KNOTS THIS MORNING GOING NORTHWEST
THIS AFTERNOON.
&&
.MARINE...
ISSUED AT 327 AM EST WED DEC 11 2013
A SMALL CRAFT ADVISORY HAS BEEN ISSUED FOR TODAY THROUGH EARLY
THURSDAY EVENING AS BRISK WEST NORTHWEST WINDS WILL RESULT IN WAVE
HEIGHTS GENERALLY AROUND 4 TO 7 FEET TODAY AND TONIGHT. WINDS
THURSDAY WILL BACK TO THE SOUTHWEST AT 15 TO 25 KNOTS RESULTING IN
CONTINUED SIGNIFICANT WAVE ACTION.
&&
.HYDROLOGY...
ISSUED AT 327 AM EST WED DEC 11 2013
TEMPERATURES WILL REMAIN WELL BELOW NORMAL THROUGH THE REST OF THE
WEEK AND WEEKEND ALONG WITH SEVERAL ROUNDS OF SNOW SHOWERS. THIS
COMBINATION OF SNOW AND COLD TEMPERATURES WILL RESULT IN POTENTIAL
FOR ICE JAM FORMATION. SO WE WILL CONTINUE TO MONITOR RIVER LEVELS
CLOSELY.
&&
.GRR WATCHES/WARNINGS/ADVISORIES...
MI...WINTER WEATHER ADVISORY UNTIL 5 PM EST THIS AFTERNOON FOR MIZ037-
043-050-056-057-064>066-071>073.
LM...SMALL CRAFT ADVISORY UNTIL 7 PM EST THURSDAY FOR LMZ844>849.
&&
$$
SYNOPSIS...LAURENS
SHORT TERM...LAURENS
LONG TERM...OSTUNO
AVIATION...OSTUNO
HYDROLOGY...LAURENS
MARINE...LAURENS
AREA FORECAST DISCUSSION
NWS HASTINGS NE
649 AM CST WED DEC 11 2013
.UPDATE...
ISSUED AT 647 AM CST WED DEC 11 2013
ONLY MADE SOME VERY MINOR TWEAKS FOR THE LATEST UPDATE. AFTER
BRINGING THE LATEST TEMPS/DEWPOINTS IN LINE WITH CURRENT
OBS AND PERUSING LATEST SETS OF MODEL DATA...OPTED TO MAKE A
VERY MINOR...ACROSS-THE-BOARD 1 DEGREE DROP IN HIGHS TODAY VERSUS
EARLIER FORECAST. IN OTHER WORDS...A TAD BIT MORE OF MAINLY THE
NORTHEAST CWA IS NOW AIMED TO FALL SHORT OF 20. ALSO BUMPED UP SKY
COVER INTO PARTLY CLOUDY TERRITORY FOR A TIME THIS MORNING IN FAR
SOUTHERN ZONES TO ACCOUNT FOR EAST-WEST-BAND OF CIRRUS THAT IS
CENTERED JUST SOUTH OF THE CWA. OTHERWISE...SMALL SPLOTCHES OF
LOW STRATUS CONTINUE TO DRIFT ACROSS LIMITED PARTS OF BOTH THE
WESTERN/EASTERN CWA...AND AS EVIDENCED BY THE OB AT HEBRON A
LITTLE WHILE AGO...SOME ROGUE/BRIEF FLURRIES CANNOT BE RULED OUT
WHEREVER THESE CLOUDS HAPPEN TO BE. AS DETAILED IN THE EARLIER
DISCUSSION...DAY SHIFT WILL HAVE TO KEEP AN EYE ON STRATUS TRENDS
OVER WESTERN NEB...JUST IN CASE SOME OF THIS STARTS TO EXPAND BACK
EASTWARD INTO THE WESTERN/NORTHWEST CWA LATER TODAY AS HINTED BY
THE LATEST RAP13 900MB RELATIVE HUMIDITY FORECAST. THIS IS NO SURE
THING THOUGH...AS THE LATEST HRRR KEEPS SKIES CLEAR PER ITS LOW
LEVEL CLOUD COVER PRODUCT.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 458 AM CST WED DEC 11 2013
IN THE MIDST OF THE MODEST TEMPERATURE-ROLLER COASTER WE ARE NOW
RIDING...TODAY STILL LOOKS LIKE THE OVERALL-COLDEST DAY OUT OF THE
NEXT 7...AS WE CATCH THE WESTERN EDGES OF A GLANCING BLOW OF
ARCTIC AIR THAT IS PRIMARILY PASSING NORTHEAST OF THE AREA. GIVEN
THAT THERE IS ESSENTIALLY ZERO RISK OF PRECIP DURING THE NEXT 24
HOURS...TEMPS CONTINUE TO BE THE MAIN ISSUE...AND AGAIN WOULD
CONSIDER THIS TO BE AN ABOVE-AVERAGE CHALLENGE GIVEN FACTORS SUCH
AS MODEL DISAGREEMENT ON THE MAGNITUDE OF THE COLD AIR TODAY...AND
HOW MUCH OF A NON-DIURNAL TREND TONIGHT COULD HAVE OWING TO STEADY
SOUTHWEST BREEZES.
STARTING OFF EARLY THIS MORNING...THE VAST MAJORITY OF THE CWA IS
SITTING UNDER CLEAR/MOSTLY CLEAR SKIES IN THE WAKE OF A QUICK-
HITTING SYSTEM THAT BROUGHT A ROUND OF FLURRIES/BRIEF VERY LIGHT
SNOW TO MAINLY THE NORTHEAST 1/2 OF THE AREA EARLIER IN THE NIGHT.
THE ONLY REAL EXCEPTION TO THE CLEAR SKIES ARE FAIRLY RANDOM
PATCHES OF LOW STRATUS BASED AROUND 2000 FT THAT ARE DRIFTING
SOUTHWARD ACROSS THE AREA...ALTHOUGH 11-3.9 MICRON SATELLITE HAS
SUGGESTED THAT THIS STRATUS IS DIMINISHING IN AREAL COVERAGE. IN
THE BIG PICTURE ALOFT...WATER VAPOR SATELLITE AND SHORT TERM MODEL
DATA CONTINUE TO DEPICT...A BROAD LONGWAVE TROUGH ENCOMPASSING
MUCH OF THE CONUS...ALTHOUGH NOW A HIGH-AMPLITUDE RIDGE IS SET UP
JUST ALONG/OFF THE PACIFIC COAST...WHILE A NEARLY CUT OFF LOW
SPINS OFF NORTHERN BAJA. CLOSER TO HOME...THE LATEST IN A SERIES
OF NORTHWEST OF NORTHWEST-FLOW/CLIPPER SHORTWAVES IS STILL IN THE
PROCESS OF SHIFTING EASTWARD ACROSS EASTERN NEB/EASTERN
DAKOTAS/IA/MN...WHILE THE ENTIRE CENTRAL PLAINS GENERALLY RESIDES
IN THE ENTRANCE REGION OF A 130+KT UPPER JET STREAK EVIDENT AT
300MB AND CENTERED FROM EASTERN IA EASTWARD. AT THE SURFACE...09Z
OBJECTIVE SURFACE ANALYSIS HIGHLIGHTS A COLD/DRY 1036MB RIDGE AXIS
CENTERED OVER SOUTHEAST SD. SOUTH OF THE HIGH CENTER...AT-TIMES BREEZY
NORTHERLY WINDS QUICKLY OVERTOOK THE ENTIRE CWA THROUGH THE
NIGHT IN THE WAKE OF THE FAIRLY STRONG COLD FRONT...WITH SUSTAINED
SPEEDS CURRENTLY AVERAGING AT LEAST 10-15 MPH WITH SOME GUSTS TO
AROUND 20 OR HIGHER. FAIRLY PRONOUNCED COLD AIR ADVECTION IS
ESTABLISHED ACROSS THE REGION...WITH 10Z TEMPS LOCALLY RANGING
FROM 8 AT ORD...TO 16 AT HASTINGS...TO 23 AT BELOIT. AT THE
CURRENT RATE...ACTUAL MORNING LOWS BY 14Z/8AM ARE ON TRACK TO
RANGE FROM AROUND 2 IN THE FAR NORTHERN CWA...TO 14-16 IN THE FAR
SOUTH.
TURNING TO THE FORECAST AND STARTING WITH THE PRE-DAWN HOURS...THE
IMMEDIATE SHORT TERM ISSUE IS NAILING DOWN THE STEADY
TEMPERATURE/DEWPOINT DROPS. THANKS TO THE FALLING TEMPS AND STEADY
NORTH WINDS...WIND CHILLS BY SUNRISE ARE PROGGED TO BE WELL INTO
THE ZERO TO -10 RANGE ACROSS ROUGHLY THE NORTHEAST HALF OF THE
CWA...WITH THE FAR NORTHEAST POSSIBLE EVEN PUSHING -15.
OTHERWISE...ALTHOUGH NOT IN THE OFFICIAL FORECAST DUE TO ITS
EXTREMELY LIMITED COVERAGE...ANY OF THE REMAINING PATCHES OF LOW
STRATUS THIS MORNING COULD SQUEEZE OUT A ROGUE...BRIEF
FLURRY...SUCH AS RECENTLY REPORTED BY AWOS SITES SUCH AS
YORK/ALBION.
FOR THE DAYTIME HOURS...THE SYNOPTIC-SCALE ALOFT WILL FEATURE THE
CONTINUED DEPARTURE OF THE AFOREMENTIONED SHORTWAVE
TROUGH...ALLOWING THE WESTERN CONUS RIDGE TO START EASING EASTWARD
INTO THE CENTRAL PLAINS...RESULTING IN SUBTLE MID LEVEL HEIGHT
RISES. AT THE SURFACE...THE STOUT RIDGE CURRENTLY CENTERED OVER SD
WILL GRADUALLY SLIDE SOUTHEAST TO AN AXIS FROM SOUTHEAST KS-
SOUTHEAST IA BY SUNSET. AS THIS FEATURE PASSES ACROSS THE
CWA...THE MORNING WILL START OUT WITH NORTHERLY BREEZES AROUND 10
MPH IN THE EAST WHILE THE WEST STARTS TO GO LIGHT/VARIABLE. AS THE
DAY GOES ON...THE FAIRLY NARROW CORRIDOR OF LIGHT/VARIABLE BREEZES
WILL SLIDE EASTWARD ACROSS THE AREA...ALLOWING SOUTHWESTERLY FLOW
TO TAKE OVER IN ITS WAKE. BY LATE AFTERNOON...SUSTAINED 5-15 MPH
SOUTHWEST BREEZES WILL BE IN PLACE...LIGHTEST IN THE SOUTHEAST AND
STRONGEST NORTHWEST. AS FOR CLOUD COVER TODAY...EXPECT
SUNNY/MOSTLY SUNNY SKIES TO DOMINATE THE MAJORITY OF THE
AREA...AND THIS IS REFLECTED IN THE FORECAST GRIDS. HOWEVER...ONE
POTENTIAL CAVEAT TO WATCH FOR IS THE EVOLUTION OF LOW STRATUS OVER
WESTERN NEB...AS MODELS SUCH AS THE RAP13 SUGGEST THAT SOME OF
THIS STRATUS COULD GET CAUGHT IN THE SOUTHWEST LOW-LEVEL FLOW ON
THE BACKSIDE OF THE RIDGE AND TRY TO PUSH EASTWARD INTO AT LEAST
THE FAR WESTERN CWA THIS AFTERNOON. HOWEVER...ODDS ARE BETTER THAT
THE MAJORITY OF THIS POTENTIAL LOW CLOUD MASS WOULD FOCUS JUST
OUTSIDE THE CWA TO THE WEST/NORTHWEST. AT ANY RATE...RUNNING WITH
THE NO-WORSE-THAN MOSTLY SUNNY ASSUMPTION...THE BIG QUESTION
TODAY CENTERS AROUND THE BATTLE BETWEEN SUN AND DEVELOPING
SOUTHWESTERLY BREEZES...WHICH FAVORS WARMING...AND THE VERY COLD
LOW LEVEL AIRMASS THAT THE AREA IS STARTING THE DAY WITH ALONG
WITH LINGERING SNOW COVER...WHICH FAVORS COLDER. AFTER
PERUSING/BLENDING VARIOUS MODEL 2M TEMPS/GUIDANCE
SOLUTIONS...OPTED TO ONLY MAKE MINOR TWEAKS TO PREVIOUS
FORECAST...AIMING FOR A RANGE IN HIGHS FROM 16-20 ACROSS ROUGHLY
THE NORTHEAST 1/2...AND 22-26 ACROSS MUCH OF THE SOUTHWEST HALF.
ADMITTEDLY...THIS HAS THE POTENTIAL TO BE AN OPTIMISTIC
FORECAST...AS SOME DATA SETS SUCH AS THE 06Z NAM AND THE 00Z MAV
SUGGEST THAT GOING HIGHS ARE ROUGHLY 5 DEGREES TOO WARM. THE
FEELING AT THIS TIME IS THAT THESE SOLUTIONS ARE JUST A BIT TOO
PESSIMISTIC THOUGH...ESPECIALLY OVER THE RATHER SNOW-FREE
WESTERN/SOUTHERN ZONES.
TURNING TO THIS EVENING/TONIGHT...THE MAIN HIGHLIGHT WILL BE
MODEST BUT STEADY LOW-LEVEL WARM AIR ADVECTION...AS 850MB TEMPS
OVER THE CWA ARE PROGGED TO CLIMB FROM BETWEEN -3 TO -7C AT
00Z/6PM TO BETWEEN ZERO AND +4C BY 12Z/6AM. THE QUESTION THOUGH IS
HOW MUCH OF THIS WARMING WILL TRULY BE REALIZED AT THE SURFACE. ON
THE LARGE SCALE ALOFT TONIGHT...STEADY MID LEVEL HEIGHT RISES WILL
CONTINUE...AS THE BROAD WESTERN CONUS RIDGE EXERTS INCREASING
INFLUENCE...FURTHER DISPLACING THE LOCAL AREA FROM STRONGER UPPER
FLOW ASSOCIATED WITH SPLIT JET STREAMS...ONE ARCING ACROSS THE
U.S/CANADA BORDER INTO THE GREAT LAKES...AND THE SOUTHERN ONE
CENTERED FROM BAJA ACROSS TX INTO THE SOUTHEAST STATES. AT THE
SURFACE...BROAD SOUTHWESTERLY FLOW WILL PERSIST ACROSS THE CENTRAL
PLAINS TO THE NORTHWEST OF THE SOUTHEAST-MOVING RIDGE AXIS...WITH
SUSTAINED SPEEDS LOCALLY RANGING FROM 8-14 MPH WITH SOME HIGHER
GUSTS THROUGH MOST OF THE NIGHT...UNTIL A LULL TO MORE SO 5-8 MPH
OCCURS VERY LATE TOWARD SUNRISE THURSDAY. THIS SORT OF OVERNIGHT
PATTERN WITH STEADY SOUTHWEST BREEZES STRONGLY ARGUES FOR NEAR-
STEADY IF NOT SLOWLY RISING TEMPS IN SOME AREAS...BUT OTHER
FACTORS SUCH AS EXPECTED CLEAR/MOSTLY CLEAR SKIES...SNOW COVER AND
THE MODEST DECREASE IN WIND SPEEDS LATE IN THE NIGHT SUGGESTS THAT
THERE WILL LIKELY BE A COMPLEX BEHAVIOR OF HOURLY TEMPS
TONIGHT...SOMEWHAT AS WHAT OCCURRED MONDAY NIGHT/EARLY TUESDAY
MORNING. IN THE END...OPTED TO LEAN ACTUAL LOWS TOWARD THE MIDDLE
GROUND OF A RATHER WIDE-RANGE OF MODEL/GUIDANCE SOLUTIONS...BUT
THIS STILL ENDED UP RESULTING IN AN UPWARD NUDGE OF 3-4 DEGREES
FROM PREVIOUS FORECAST...CALLING FOR A FAIRLY UNIFORM RANGE ACROSS
THE CWA OF 9-12 DEGREES. THESE VALUES ARE A SOLID 3-5 DEGREES
ABOVE A 00Z MET/MAV GUIDANCE BLEND...WHICH JUST LOOKS TOO COLD
GIVEN THE WESTERLY FLOW/WARM AIR ADVECTION. BY THE SAME
TOKEN...THE OFFICIAL FORECAST IS NOT AS WARM AS RAW 2M TEMPS FROM
MODELS SUCH AS THE GFS/ECMWF...WHICH SUGGEST MUCH OF THE
WEST/SOUTH COULD HOLD ABOVE 15 THROUGH THE NIGHT.
.LONG TERM...(THURSDAY THROUGH TUESDAY)
ISSUED AT 458 AM CST WED DEC 11 2013
THE PRIMARY CHALLENGE WILL CONTINUE TO BE THE TEMPERATURE FORECAST
AND HOW TO HANDLE THE SNOW COVER IMPACTS ON TEMPERATURES. WE ARE IN
FOR A VERY NICE WARM-UP ON THURSDAY...LIKELY THE WARMEST DAY IN OVER
A WEEK. EXPECT A COLD FRONTAL PASSAGE ON FRIDAY THAT WILL RESULT IN
A RETURN OF SUB-FREEZING TEMPERATURES FOR MOST AREAS. SUNDAY SHOULD
BE A TRANSITION DAY WITH WARMER WESTERLY WINDS FOLLOWED BY EVEN
WARMER TEMPERATURES EARLY NEXT WEEK WHEN HIGHS SHOULD GENERALLY BE
ABOVE FREEZING. AT THIS TIME WE ARE NOT EXPECTING ANY ADDITIONAL
ACCUMULATING SNOWFALL EVENTS DURING THE LONG TERM PERIOD BUT CAN NOT
COMPLETELY RULE OUT FLURRIES.
THURSDAY...THE SFC WIND WILL TURN SOUTHWESTERLY AS THE SFC HIGH
SLIDES EAST AND AN UPPER RIDGE WILL BUILD ACROSS THE WESTERN CONUS
SENDING WARMER AIR ALOFT INTO THE HIGH PLAINS. 850 MB TEMPERATURES
WILL RISE BY AROUND 10 TO 15C FROM WEDNESDAY AFTERNOON TO THURSDAY
AFTERNOON. THEREFORE...EXPECT A QUICK WARM-UP WITH THE SNOW COVER
BEING THE ONLY THING LEFT LIMITING THE RISE. THERE CERTAINLY COULD
BE A 10 DEGREE OR GREATER DIFFERENCE IN HIGH TEMPERATURES BETWEEN
LOCATIONS WITH SNOW AND THOSE WITHOUT SNOW. FOR INSTANCE...WILL CALL
FOR A HIGH OF 42 IN ORD...AND UPPER 40S IN SOUTHERN TIER OF KS
COUNTIES WHERE THERE IS NO SNOW...BUT WILL ONLY CALL FOR A HIGH OF
32 IN HASTINGS DUE TO SNOW COVER.
FRIDAY...UNCERTAINTY IN TEMPERATURE FORECAST IS RATHER HIGH AS A
COLD FRONT WILL TRACK THROUGH DURING THE DAY AND THE MAGNITUDE OF
THE COLD AIR VARIES FROM MODEL TO MODEL. THE NAM RAW TEMPERATURES
ARE TOO COLD WITH THE NAM BELIEVING THERE IS A DEEPER AND MORE
WIDESPREAD SNOW PACK THAN WE REALLY HAVE. THE 00Z ECMWF MAY BE A
LITTLE TOO WARM AND HAVE LEANED TOWARD THE MIDDLE GROUND 00Z GFS. WE
SHOULD GENERALLY BE LOOKING AT UPPER 20S TO LOWER 30S ACROSS MOST OF
THE FORECAST AREA. DID NOT ACCOUNT FOR A SNOW COVER DIFFERENCE IN
THE TEMPERATURE FIELD DUE TO UNCERTAINTY WITH REGARD TO HOW MUCH
SNOW COVER WILL REMAIN AFTER THURSDAY. WITH REGARD TO
PRECIPITATION...IT SHOULD BE DRY...BUT IT MAY BE A CLOSE CALL FOR
SOUTHEASTERN ZONES AS A SHORTWAVE TRACKS ACROSS THE SOUTHERN PLAINS
AND SPREADS LIGHT SNOW AS FAR NORTH AS SOUTH CENTRAL KANSAS INTO
NORTHEAST KANSAS.
SATURDAY...FORECAST MODELS ARE FAIRLY CONSISTENT IN SHOWING A COOL
HIGH PRESSURE OVERHEAD WITH LIGHT NORTHERLY FLOW BEHIND A DEPARTING
UPPER LEVEL WAVE. NORTHEAST ZONES WILL CERTAINLY GET THE FULLER
BLAST OF THE COLD AND WILL STRUGGLE INTO THE MID 20S WHILE OUR
SOUTHWESTERN ZONES FROM BEAVER CITY TO STOCKTON MAY FLIRT WITH HIGHS
NEAR THE FREEZING MARK. SUBSIDENCE AND DRY WEATHER IS EXPECTED.
SUNDAY THROUGH TUESDAY...UNCERTAINTY REMAINS HIGH BUT HAS IMPROVED
SOME WITH MODELS TRENDING CLOSER TOGETHER AND MORE IN LINE WITH A
WARMER WEATHER REGIME. USED THE ALLBLEND MODEL SOLUTION FOR THESE
OUTER PERIODS...WHICH MAY BE A BIT TOO COOL IF CURRENT WARMER MODEL
TRENDS CONTINUE AND PREVAIL. THE OVERALL PATTERN THESE DAYS WILL BE
AN UPPER RIDGE OVER THE WESTERN CONUS AND THE JET STREAM GENERALLY
NORTH OF OUR FORECAST AREA. EXPECT TEMPERATURES WILL BE WARMER
SUNDAY THAN ON SATURDAY AND THEN EVEN WARMER STILL BY MONDAY AND
TUESDAY. ANY REMAINING SNOW WILL LIKELY MELT UNDER THIS SET UP.
THERE IS STILL HOPE FOR THOSE WANTING A WHITE CHRISTMAS AS BOTH THE
00Z GFS AND 00Z ECWMF SHOW A SHARP TURN TOWARDS COLD BY DEC 20TH OR
21ST WITH THE POTENTIAL OF A WINTER STORM SYSTEM SOMEWHERE IN THE
PLAINS JUST BEFORE CHRISTMAS BUT WAY TO EARLY TO PIN POINT ANYTHING.
&&
.AVIATION...(FOR THE 12Z KGRI TAF THROUGH 12Z THURSDAY MORNING)
ISSUED AT 550 AM CST WED DEC 11 2013
CONFIDENCE REMAINS HIGH IN VFR CEILING/VISIBILITY THROUGH THE
VAST MAJORITY OF THE PERIOD...WITH THE ONLY FORESEEN EXCEPTION
CONSISTING OF A SMALL AREA OF BKN/OVC STRATUS THAT IS LURKING
VERY NEAR/OVER THE TERMINAL RIGHT AWAY THIS MORNING. GIVEN THAT
ANY LOW CEILING IS ONLY EXPECTED TO LAST A SHORT TIME...WILL ONLY
CARRY A 2-HOUR TEMPO GROUP FOR IT. ONCE THIS STRATUS VACATES...THE
REMAINDER OF THE PERIOD SHOULD BE LARGELY CLOUD-FREE. DURING THE
LATTER HALF OF THE PERIOD...MAINLY BETWEEN 02Z-07Z...CONFIDENCE
HAS INCREASED ENOUGH IN A PERIOD OF LOW LEVEL WIND SHEAR TO
INTRODUCE INTO THE TAF...AS SURFACE WINDS AVERAGE AROUND 13KT FROM
THE SOUTHWEST WHILE WINDS WITHIN THE LOWEST 1200 FT AGL ACCELERATE
TO OVER 40KT FROM THE WEST...CREATING 30-35KT OF WIND VECTOR
DIFFERENCE BETWEEN THESE LEVELS. BACKING UP TO THE DAYTIME
HOURS...SURFACE BREEZES WILL START OUT NORTHERLY BEFORE BECOMING
FAIRLY LIGHT/VARIABLE AROUND MID-DAY...AND THEN BECOMING
ESTABLISHED FROM THE SOUTHWEST DURING THE AFTERNOON.
&&
.GID WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
KS...NONE.
&&
$$
UPDATE...PFANNKUCH
SHORT TERM...PFANNKUCH
LONG TERM...WESELY
AVIATION...PFANNKUCH
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
800 AM CST WED DEC 11 2013
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 334 AM CST WED DEC 11 2013
MAIN FORECAST CONCERNS ARE ON WIND CHILLS THROUGH TONIGHT AND
PRECIPITATION CHANCES TONIGHT.
CURRENTLY AS OF 09Z...WATER VAPOR LOOP AND RAP 500MB HEIGHT ANALYSIS
SHOWED UPPER RIDGING NEAR THE WEST COAST OF THE U.S....BROAD
TROUGHING OVER THE EAST HALF OF CANADA...AND A SHORTWAVE TROUGH
STRETCHING FROM MN INTO NEBRASKA. AHEAD OF THIS SHORTWAVE TROUGH...A
FRONTOGENESIS BAND OF SNOW ENCOMPASSED MUCH OF EASTERN IOWA INTO
SOUTHERN WI...WHILE CLOUDS COVERED MUCH OF THE FORECAST AREA.
HOWEVER...CLEARING ASSOCIATED WITH SUBSIDENCE IN THE TROUGH WAS
QUICKLY APPROACHING THE FORECAST AREA FROM CENTRAL MN. THIS CLEARING
WAS RIGHT BEHIND A COLD FRONT...WHICH ALSO REPRESENTS AN ARCTIC
AIRMASS POISED TO COME INTO THE AREA TODAY. READINGS ARE BELOW ZERO
FROM NORTH DAKOTA INTO CENTRAL MN...AND IN MANY SPOTS TEENS BELOW
ZERO. 850MB STANDARDIZED TEMPERATURE ANOMALIES ASSOCIATED WITH THIS
ARCTIC AIRMASS ARE 2 BELOW NORMAL. ACCOMPANYING THE ARCTIC AIR ARE
SOME BRISK NORTHWEST WINDS...PARTICULARLY WITH THE ISALLOBARIC PUSH
RIGHT BEHIND THE COLD FRONT. THESE WINDS ARE KNOCKING WIND CHILLS
DOWN TO 20 TO 35 BELOW FROM CENTRAL MN THROUGH NORTHERN WI
NORTHWESTWARD.
THE COLD AIR AND CLEARING SEEN OVER CENTRAL MN WILL RUSH INTO THE
FORECAST AREA QUICKLY THIS MORNING...ASSOCIATED WITH THE COLD
FRONTAL AND SHORTWAVE TROUGH PASSAGE. WINDS SHOULD STAY BRISK ALL
DAY AS A SURFACE OVER THE WESTERN DAKOTAS ENDS UP SLIDING WELL TO
OUR SOUTH...INTO NORTHERN MO BY 00Z. THE STRONGEST WINDS ARE LIKELY
THIS MORNING AS PRESSURES RISE RAPIDLY. TEMPERATURES LOOK TO FALL
THROUGH MID MORNING...MAY GET A LITTLE BUMP UP EARLY THIS AFTERNOON
WITH DAYTIME HEATING...AND FALL YET AGAIN ONCE THE SUN STARTS GOING
DOWN. THUS...ITS GOING TO BE TOUGH TO WARM TODAY. HIGHS IN THE
SINGLE DIGITS ABOVE ZERO APPEARS TO BE ALL WE CAN GET...WITH
LOCATIONS NORTH OF HIGHWAY 10 NOT EVEN REACHING ZERO. FACTOR IN THE
WIND AND MUCH OF THE AREA WILL SEE WIND CHILLS REACHING 20 BELOW
ZERO OR COLDER AT TIMES...ESPECIALLY THIS MORNING AND LATE TODAY.
REGARDING HAZARDS...LIKELY SOMETIME BETWEEN 12-13Z TODAY WE CAN
TRANSITION THE WINTER WEATHER ADVISORY OVER TO A WIND CHILL
ADVISORY IN NORTHEAST IOWA.
THIS SHOT OF ARCTIC AIR APPEARS TO BE SHORT-LIVED...HOWEVER. A
SHORTWAVE SEEN OVER ALBERTA IS PROGGED BY MODELS TO DROP DOWN
THROUGH CENTRAL MN AND WI BETWEEN 06-12Z TONIGHT. THE APPROACH OF
THE SHORTWAVE HELPS TO SWING WINDS AROUND TO THE SOUTHWEST...AND
SPREAD SOME MID/HIGH CLOUDS INTO THE AREA RESULTING FROM DPVA AND
ISENTROPIC LIFT. SO AFTER SOME COOLING FROM RADIATIONAL PROCESSES IN
THE EVENING...ADVECTIVE PROCESSES WILL HELP TEMPERATURES CLIMB
THEREAFTER. GIVEN THE COLD EVENING...EXTENDED THE WIND CHILL
ADVISORY THROUGH 12Z THU FOR SOUTHEAST MN INTO SOUTHWEST AND
CENTRAL WI. EXPANDED BOTH IN TIME AND AREA THE ADVISORY TO HELP
BLEND WITH MKX AND DVN OFFICES. THE NEXT QUESTION IS IF ANY SNOW
CAN FALL WITH THE SHORTWAVE. THE 11.00Z GFS/CANADIAN/ECMWF ALL
PRODUCE A BAND OF LIGHT QPF...WITH SOUNDINGS SUGGESTING THE
FORCING IS MOSTLY CO- LOCATED WITH THE DENDRITIC GROWTH ZONE. THE
AFOREMENTIONED MODELS ALL SUGGEST A QUICK MOVING BAND...LIMITING
ACCUMULATIONS...BUT A FEW TENTHS SEEM REASONABLE. HAVE RAISED
PRECIPITATION CHANCES TOWARDS 60. NAM IS THE ONLY MODEL NOT
SHOWING ANY PRECIPITATION...BUT EVEN IT HAS INDICATIONS OF THE
FORCING.
.LONG TERM...(THURSDAY THROUGH TUESDAY)
ISSUED AT 334 AM CST WED DEC 11 2013
MAIN LONG TERM FORECAST CONCERNS ARE ON MINIMAL PRECIPITATION
CHANCES THROUGHOUT.
SOME DEAMPLIFICATION OF THE FLOW ACROSS THE NORTHERN U.S. IS PROGGED
TO OCCUR THURSDAY THROUGH FRIDAY IN RESPONSE TO A TROUGH DROPPING
DOWN THROUGH THE PACIFIC NORTHWEST. THE SWITCH TO A ZONAL FLOW
PATTERN IN THE NORTHERN STREAM APPEARS TO HAVE PLENTY OF MID/UPPER
LEVEL MOISTURE...WHICH IS GOING TO MANIFEST ITSELF IN A LOT OF
CLOUDS. PRECIPITATION CHANCES OVERALL LOOK PRETTY MINIMAL...
THOUGH...AS PLENTIFUL DRY LOW LEVEL AIR IS IN PLACE. ADDITIONALLY...
FORCING APPEARS RESTRICTED TO SOME WEAK MID LEVEL FRONTOGENESIS
STRETCHING FROM NORTHERN/CENTRAL MN INTO NORTHERN WI THU NIGHT AND
FRIDAY. THIS FORCING COULD SQUEEZE OUT SOME SNOW...BUT CONFIDENCE IS
ONLY HIGH ENOUGH FOR A 20 PERCENT CHANCE NORTH OF HIGHWAY 10.
REGARDING THAT AFOREMENTIONED FRONTOGENESIS...THIS WILL OCCUR BEHIND
A COLD FRONTAL PASSAGE PROGGED TO MOVE THROUGH THE AREA THU NIGHT.
SO AFTER A WARMER THURSDAY IN RESPONSE TO LOW LEVEL WARM
ADVECTION...TEMPERATURES HEAD BACK DOWN THU NIGHT...BUT NOT NEARLY
AS COLD AS IT HAS BEEN. DESPITE THE COLD ADVECTION...TEMPERATURES
FRIDAY SHOULD REBOUND CLOSE TO THURSDAYS HIGHS.
FOR FRIDAY NIGHT AND SATURDAY...THE FOCUS HAS BEEN ON A SHORTWAVE
TROUGH AND GENERAL SYSTEM COMING OUT OF THE CENTRAL PLAINS. THIS
SHORTWAVE TROUGH IS CURRENTLY AN UPPER LOW SITTING OFF THE FAR
SOUTHERN CALIFORNIA COAST. 11.00Z ECMWF/GFS/CANADIAN HAVE TRENDED
SLIGHTLY FARTHER SOUTHEAST WITH THIS SYSTEM...AND AS SUCH...THE
PRECIPITATION ALSO MOVED A LITTLE FARTHER AWAY. THERE STILL ARE
INDICATIONS THAT THE MID LEVEL FRONTOGENESIS SITTING OVER NORTHERN
WI ON FRIDAY WILL SLIDE SOUTH OVER THE REST OF THE AREA FRIDAY
NIGHT...POSSIBLY SQUEEZING OUT A LITTLE LIGHT SNOW.
THEREFORE...HAVE HAD TO MAINTAIN SOME 20-40 PERCENT
CHANCES...HIGHEST BETWEEN 06-12Z SATURDAY. CHANCES CONTINUE
THROUGH THE DAY SATURDAY AND INTO SATURDAY NIGHT...MORE IN
RESPONSE TO A POTENT SHORTWAVE TROUGH DROPPING DOWN FROM MANITOBA
INTO UPPER MICHIGAN.
FOR SUNDAY AND BEYOND...SUNDAY IS LOOKING CHILLY AS THE POTENT
TROUGH BRINGS DOWN A BRIEF SHOT OF ARCTIC AIR WITH IT ON ITS BACK
SIDE. 850MB TEMPS FALL TO -14 TO -20C AT 18Z SUNDAY PER 11.00Z
ECMWF...COLDEST OVER TAYLOR COUNTY. MAY GET CLOSE FOR NEEDING A WIND
CHILL ADVISORY SUNDAY MORNING. A WARM ADVECTION PATTERN THEN LOOKS
TO ENSUE FOR SUNDAY NIGHT INTO MONDAY AS YET ANOTHER DECENT
SHORTWAVE TROUGH TRACKS FROM MANITOBA INTO UPPER MICHIGAN. FOLLOWED
CONSENSUS AND INCLUDED 20 PERCENT CHANCES FOR MONDAY. TEMPERATURES
MAY REBOUND HIGHER TOO THAN CURRENTLY FORECAST...BUT GIVEN HOW FAR
OUT THIS PERIOD IS IN THE FORECAST...STAYED CLOSER TO A MODEL
CONSENSUS WITH HIGHS IN THE 15-20 RANGE.
FOR THOSE LOOKING FOR A WARM-UP...THE ECMWF CONTINUES TO HINT AT ONE
FOR THE MIDDLE TO END OF NEXT WEEK AS A DEEP TROUGH FORMS OVER THE
WESTERN U.S.. THE CFS HAS ALSO BEEN ADVERTISING ABOVE NORMAL
TEMPERATURES DURING THIS SAME TIME PERIOD.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z THURSDAY MORNING)
ISSUED AT 532 AM CST WED DEC 11 2013
PATCHY BLOWING SNOW IS POSSIBLE AT KRST EARLY THIS
MORNING...OTHERWISE VFR CONDITIONS ARE EXPECTED AT THE TAF SITES
THROUGH THIS EVENING. PLAN ON NORTHWEST WINDS OF 12 TO 14 KTS
THIS MORNING...THEN DIMINISHING INTO THE 8 TO 10 KT RANGE THIS
AFTERNOON AND BECOMING WESTERLY. A FAST MOVING UPPER LEVEL
DISTURBANCE WILL MOVE ACROSS THE AREA LATE TONIGHT BRINGING LIGHT
SNOW OR FLURRIES TO THE TAF SITES. MVFR CONDITIONS ARE POSSIBLE
TONIGHT IN THE SNOW WITH VISIBILITIES IN THE 4 TO 5 SM RANGE AND
CEILINGS LOWERING TO AROUND 2 KFT. THE SNOW LOOKS TO START AT KRST
AROUND 08Z AND AT KLSE AROUND 09Z. MOST OF THE SNOW SHOULD PASS
NORTHEAST OF THE TAF SITES BUT WILL HAVE TO KEEP A CLOSE EYE ON
THIS SYSTEM THIS EVENING INTO THE OVERNIGHT HOURS.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
WI...WIND CHILL ADVISORY UNTIL 6 AM CST THURSDAY FOR WIZ017-029-
032>034-041>044.
WIND CHILL ADVISORY FROM 6 PM THIS EVENING TO 6 AM CST THURSDAY
FOR WIZ053>055-061.
MN...WIND CHILL ADVISORY UNTIL 6 AM CST THURSDAY FOR MNZ079-086>088-
094>096.
IA...WIND CHILL ADVISORY UNTIL 6 AM CST THURSDAY FOR IAZ008>010-018-
019-029.
WIND CHILL ADVISORY FROM 6 PM THIS EVENING TO 6 AM CST THURSDAY
FOR IAZ011-030.
&&
$$
SHORT TERM...AJ
LONG TERM...AJ
AVIATION...WETENKAMP
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
532 AM CST WED DEC 11 2013
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 334 AM CST WED DEC 11 2013
MAIN FORECAST CONCERNS ARE ON WIND CHILLS THROUGH TONIGHT AND
PRECIPITATION CHANCES TONIGHT.
CURRENTLY AS OF 09Z...WATER VAPOR LOOP AND RAP 500MB HEIGHT ANALYSIS
SHOWED UPPER RIDGING NEAR THE WEST COAST OF THE U.S....BROAD
TROUGHING OVER THE EAST HALF OF CANADA...AND A SHORTWAVE TROUGH
STRETCHING FROM MN INTO NEBRASKA. AHEAD OF THIS SHORTWAVE TROUGH...A
FRONTOGENESIS BAND OF SNOW ENCOMPASSED MUCH OF EASTERN IOWA INTO
SOUTHERN WI...WHILE CLOUDS COVERED MUCH OF THE FORECAST AREA.
HOWEVER...CLEARING ASSOCIATED WITH SUBSIDENCE IN THE TROUGH WAS
QUICKLY APPROACHING THE FORECAST AREA FROM CENTRAL MN. THIS CLEARING
WAS RIGHT BEHIND A COLD FRONT...WHICH ALSO REPRESENTS AN ARCTIC
AIRMASS POISED TO COME INTO THE AREA TODAY. READINGS ARE BELOW ZERO
FROM NORTH DAKOTA INTO CENTRAL MN...AND IN MANY SPOTS TEENS BELOW
ZERO. 850MB STANDARDIZED TEMPERATURE ANOMALIES ASSOCIATED WITH THIS
ARCTIC AIRMASS ARE 2 BELOW NORMAL. ACCOMPANYING THE ARCTIC AIR ARE
SOME BRISK NORTHWEST WINDS...PARTICULARLY WITH THE ISALLOBARIC PUSH
RIGHT BEHIND THE COLD FRONT. THESE WINDS ARE KNOCKING WIND CHILLS
DOWN TO 20 TO 35 BELOW FROM CENTRAL MN THROUGH NORTHERN WI
NORTHWESTWARD.
THE COLD AIR AND CLEARING SEEN OVER CENTRAL MN WILL RUSH INTO THE
FORECAST AREA QUICKLY THIS MORNING...ASSOCIATED WITH THE COLD
FRONTAL AND SHORTWAVE TROUGH PASSAGE. WINDS SHOULD STAY BRISK ALL
DAY AS A SURFACE OVER THE WESTERN DAKOTAS ENDS UP SLIDING WELL TO
OUR SOUTH...INTO NORTHERN MO BY 00Z. THE STRONGEST WINDS ARE LIKELY
THIS MORNING AS PRESSURES RISE RAPIDLY. TEMPERATURES LOOK TO FALL
THROUGH MID MORNING...MAY GET A LITTLE BUMP UP EARLY THIS AFTERNOON
WITH DAYTIME HEATING...AND FALL YET AGAIN ONCE THE SUN STARTS GOING
DOWN. THUS...ITS GOING TO BE TOUGH TO WARM TODAY. HIGHS IN THE
SINGLE DIGITS ABOVE ZERO APPEARS TO BE ALL WE CAN GET...WITH
LOCATIONS NORTH OF HIGHWAY 10 NOT EVEN REACHING ZERO. FACTOR IN THE
WIND AND MUCH OF THE AREA WILL SEE WIND CHILLS REACHING 20 BELOW
ZERO OR COLDER AT TIMES...ESPECIALLY THIS MORNING AND LATE TODAY.
REGARDING HAZARDS...LIKELY SOMETIME BETWEEN 12-13Z TODAY WE CAN
TRANSITION THE WINTER WEATHER ADVISORY OVER TO A WIND CHILL
ADVISORY IN NORTHEAST IOWA.
THIS SHOT OF ARCTIC AIR APPEARS TO BE SHORT-LIVED...HOWEVER. A
SHORTWAVE SEEN OVER ALBERTA IS PROGGED BY MODELS TO DROP DOWN
THROUGH CENTRAL MN AND WI BETWEEN 06-12Z TONIGHT. THE APPROACH OF
THE SHORTWAVE HELPS TO SWING WINDS AROUND TO THE SOUTHWEST...AND
SPREAD SOME MID/HIGH CLOUDS INTO THE AREA RESULTING FROM DPVA AND
ISENTROPIC LIFT. SO AFTER SOME COOLING FROM RADIATIONAL PROCESSES IN
THE EVENING...ADVECTIVE PROCESSES WILL HELP TEMPERATURES CLIMB
THEREAFTER. GIVEN THE COLD EVENING...EXTENDED THE WIND CHILL
ADVISORY THROUGH 12Z THU FOR SOUTHEAST MN INTO SOUTHWEST AND
CENTRAL WI. EXPANDED BOTH IN TIME AND AREA THE ADVISORY TO HELP
BLEND WITH MKX AND DVN OFFICES. THE NEXT QUESTION IS IF ANY SNOW
CAN FALL WITH THE SHORTWAVE. THE 11.00Z GFS/CANADIAN/ECMWF ALL
PRODUCE A BAND OF LIGHT QPF...WITH SOUNDINGS SUGGESTING THE
FORCING IS MOSTLY CO- LOCATED WITH THE DENDRITIC GROWTH ZONE. THE
AFOREMENTIONED MODELS ALL SUGGEST A QUICK MOVING BAND...LIMITING
ACCUMULATIONS...BUT A FEW TENTHS SEEM REASONABLE. HAVE RAISED
PRECIPITATION CHANCES TOWARDS 60. NAM IS THE ONLY MODEL NOT
SHOWING ANY PRECIPITATION...BUT EVEN IT HAS INDICATIONS OF THE
FORCING.
.LONG TERM...(THURSDAY THROUGH TUESDAY)
ISSUED AT 334 AM CST WED DEC 11 2013
MAIN LONG TERM FORECAST CONCERNS ARE ON MINIMAL PRECIPITATION
CHANCES THROUGHOUT.
SOME DEAMPLIFICATION OF THE FLOW ACROSS THE NORTHERN U.S. IS PROGGED
TO OCCUR THURSDAY THROUGH FRIDAY IN RESPONSE TO A TROUGH DROPPING
DOWN THROUGH THE PACIFIC NORTHWEST. THE SWITCH TO A ZONAL FLOW
PATTERN IN THE NORTHERN STREAM APPEARS TO HAVE PLENTY OF MID/UPPER
LEVEL MOISTURE...WHICH IS GOING TO MANIFEST ITSELF IN A LOT OF
CLOUDS. PRECIPITATION CHANCES OVERALL LOOK PRETTY MINIMAL...
THOUGH...AS PLENTIFUL DRY LOW LEVEL AIR IS IN PLACE. ADDITIONALLY...
FORCING APPEARS RESTRICTED TO SOME WEAK MID LEVEL FRONTOGENESIS
STRETCHING FROM NORTHERN/CENTRAL MN INTO NORTHERN WI THU NIGHT AND
FRIDAY. THIS FORCING COULD SQUEEZE OUT SOME SNOW...BUT CONFIDENCE IS
ONLY HIGH ENOUGH FOR A 20 PERCENT CHANCE NORTH OF HIGHWAY 10.
REGARDING THAT AFOREMENTIONED FRONTOGENESIS...THIS WILL OCCUR BEHIND
A COLD FRONTAL PASSAGE PROGGED TO MOVE THROUGH THE AREA THU NIGHT.
SO AFTER A WARMER THURSDAY IN RESPONSE TO LOW LEVEL WARM
ADVECTION...TEMPERATURES HEAD BACK DOWN THU NIGHT...BUT NOT NEARLY
AS COLD AS IT HAS BEEN. DESPITE THE COLD ADVECTION...TEMPERATURES
FRIDAY SHOULD REBOUND CLOSE TO THURSDAYS HIGHS.
FOR FRIDAY NIGHT AND SATURDAY...THE FOCUS HAS BEEN ON A SHORTWAVE
TROUGH AND GENERAL SYSTEM COMING OUT OF THE CENTRAL PLAINS. THIS
SHORTWAVE TROUGH IS CURRENTLY AN UPPER LOW SITTING OFF THE FAR
SOUTHERN CALIFORNIA COAST. 11.00Z ECMWF/GFS/CANADIAN HAVE TRENDED
SLIGHTLY FARTHER SOUTHEAST WITH THIS SYSTEM...AND AS SUCH...THE
PRECIPITATION ALSO MOVED A LITTLE FARTHER AWAY. THERE STILL ARE
INDICATIONS THAT THE MID LEVEL FRONTOGENESIS SITTING OVER NORTHERN
WI ON FRIDAY WILL SLIDE SOUTH OVER THE REST OF THE AREA FRIDAY
NIGHT...POSSIBLY SQUEEZING OUT A LITTLE LIGHT SNOW.
THEREFORE...HAVE HAD TO MAINTAIN SOME 20-40 PERCENT
CHANCES...HIGHEST BETWEEN 06-12Z SATURDAY. CHANCES CONTINUE
THROUGH THE DAY SATURDAY AND INTO SATURDAY NIGHT...MORE IN
RESPONSE TO A POTENT SHORTWAVE TROUGH DROPPING DOWN FROM MANITOBA
INTO UPPER MICHIGAN.
FOR SUNDAY AND BEYOND...SUNDAY IS LOOKING CHILLY AS THE POTENT
TROUGH BRINGS DOWN A BRIEF SHOT OF ARCTIC AIR WITH IT ON ITS BACK
SIDE. 850MB TEMPS FALL TO -14 TO -20C AT 18Z SUNDAY PER 11.00Z
ECMWF...COLDEST OVER TAYLOR COUNTY. MAY GET CLOSE FOR NEEDING A WIND
CHILL ADVISORY SUNDAY MORNING. A WARM ADVECTION PATTERN THEN LOOKS
TO ENSUE FOR SUNDAY NIGHT INTO MONDAY AS YET ANOTHER DECENT
SHORTWAVE TROUGH TRACKS FROM MANITOBA INTO UPPER MICHIGAN. FOLLOWED
CONSENSUS AND INCLUDED 20 PERCENT CHANCES FOR MONDAY. TEMPERATURES
MAY REBOUND HIGHER TOO THAN CURRENTLY FORECAST...BUT GIVEN HOW FAR
OUT THIS PERIOD IS IN THE FORECAST...STAYED CLOSER TO A MODEL
CONSENSUS WITH HIGHS IN THE 15-20 RANGE.
FOR THOSE LOOKING FOR A WARM-UP...THE ECMWF CONTINUES TO HINT AT ONE
FOR THE MIDDLE TO END OF NEXT WEEK AS A DEEP TROUGH FORMS OVER THE
WESTERN U.S.. THE CFS HAS ALSO BEEN ADVERTISING ABOVE NORMAL
TEMPERATURES DURING THIS SAME TIME PERIOD.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z THURSDAY MORNING)
ISSUED AT 532 AM CST WED DEC 11 2013
PATCHY BLOWING SNOW IS POSSIBLE AT KRST EARLY THIS
MORNING...OTHERWISE VFR CONDITIONS ARE EXPECTED AT THE TAF SITES
THROUGH THIS EVENING. PLAN ON NORTHWEST WINDS OF 12 TO 14 KTS
THIS MORNING...THEN DIMINISHING INTO THE 8 TO 10 KT RANGE THIS
AFTERNOON AND BECOMING WESTERLY. A FAST MOVING UPPER LEVEL
DISTURBANCE WILL MOVE ACROSS THE AREA LATE TONIGHT BRINGING LIGHT
SNOW OR FLURRIES TO THE TAF SITES. MVFR CONDITIONS ARE POSSIBLE
TONIGHT IN THE SNOW WITH VISIBILITIES IN THE 4 TO 5 SM RANGE AND
CEILINGS LOWERING TO AROUND 2 KFT. THE SNOW LOOKS TO START AT KRST
AROUND 08Z AND AT KLSE AROUND 09Z. MOST OF THE SNOW SHOULD PASS
NORTHEAST OF THE TAF SITES BUT WILL HAVE TO KEEP A CLOSE EYE ON
THIS SYSTEM THIS EVENING INTO THE OVERNIGHT HOURS.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
WI...WINTER WEATHER ADVISORY UNTIL 9 AM CST THIS MORNING FOR WIZ054-
061.
WIND CHILL ADVISORY UNTIL 6 AM CST THURSDAY FOR WIZ017-029-
032>034-041>044.
WIND CHILL ADVISORY FROM 6 PM THIS EVENING TO 6 AM CST THURSDAY
FOR WIZ053-055.
MN...WIND CHILL ADVISORY UNTIL 6 AM CST THURSDAY FOR MNZ079-086>088-
094>096.
IA...WINTER WEATHER ADVISORY UNTIL 9 AM CST THIS MORNING FOR
IAZ008>011-018-019-029-030.
&&
$$
SHORT TERM...AJ
LONG TERM...AJ
AVIATION...WETENKAMP
AREA FORECAST DISCUSSION
NWS GOODLAND KS
1258 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 18Z TAFS THROUGH 18Z THURSDAY)
ISSUED AT 1023 AM MST WED DEC 11 2013
LOW STRATUS HAS OVERSPREAD BOTH TERMINALS THIS MORNING WITH IFR
CIGS AT KGLD AND MVFR CIGS AT KMCK. SHORT RANGE GUIDANCE GENERALLY
SUPPORTS THIS ACTIVITY DISSIPATING EARLY THIS AFTERNOON AS SW FLOW
BRING DRY AIR BACK INTO THE LOWER ATMOSPHERE. SATELLITE TRENDS
ALREADY INDICATE EDGES OF STRATUS ERODING AND AN OVERALL THINNING
OF THE CLOUD LAYER. I KEPT CIGS PREVAILING THROUGH 20Z BASED ON
SIMILAR TIMING OF RAP/HRRR WITH VFR CONDITIONS THEN PREVAILING
THROUGH THE REST OF THE TAF PERIOD. AS SKIES CLEAR AND DAYTIME
MIXING INCREASE WE SHOULD SEE SOUTH WINDS GUSTING IN THE 20-25KT
RANGE AT KGLD. I HAVE LESS CONFIDENCE IN WINDS MIXING TO THE
SURFACE AT KMCK. BY TONIGHT WINDS SHOULD DECREASE BELOW 12KT AT
BOTH TERMINALS AND REMAIN BELOW 12KT THROUGH THE REST OF THE TAF
PERIOD.
&&
.GLD WATCHES/WARNINGS/ADVISORIES...
KS...NONE.
CO...NONE.
NE...NONE.
&&
$$
SHORT TERM...DR
LONG TERM...024
AVIATION...DR
AREA FORECAST DISCUSSION
NWS GRAY ME
303 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 /THROUGH TONIGHT/...
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.
OTHERWISE...UPSLOPE SNOW SHOWERS WILL LIKELY LEAD TO ACCUMULATING
SNOWFALL ACROSS THE HIGHER NORTHWEST FACING TERRAIN TONIGHT. LOOK
FOR UP TO 2-4 INCHES OF DRY...POWDERY SNOW IN THIS REGION.
TEMPERATURES WILL FALL TO NEAR ZERO IN THE NORTH WITH THE
CONTINUING NORTHWEST WIND.
&&
.SHORT TERM /THURSDAY 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 FURTHER 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 /20Z 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 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 1 AM EST THURSDAY FOR ANZ151-153.
GALE WARNING UNTIL 1 AM EST THURSDAY FOR ANZ150-152-154.
&&
$$
CANNON/POHL
AREA FORECAST DISCUSSION
NWS GRAY ME
302 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 /THROUGH TONIGHT/...
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.
OTHERWISE...UPSLOPE SNOW SHOWERS WILL LIKELY LEAD TO ACCUMULATING
SNOWFALL ACROSS THE HIGHER NORTHWEST FACING TERRAIN TONIGHT. LOOK
FOR UP TO 2-4 INCHES OF DRY...POWDERY SNOW IN THIS REGION.
TEMPERATURES WILL FALL TO NEAR ZERO IN THE NORTH WITH THE
CONTINUING NORTHWEST WIND.
&&
.SHORT TERM /THURSDAY 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 FURTHER 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 /20Z 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 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 1 AM EST THURSDAY FOR ANZ151-153.
GALE WARNING UNTIL 1 AM EST THURSDAY FOR ANZ150-152-154.
&&
$$
CANNON/POHL
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
431 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 18Z TAFS THROUGH 18Z THURSDAY AFTERNOON)
ISSUED AT 100 PM EST WED DEC 11 2013
LAKE EFFECT SNOW IS EXPECTED TO CONTINUE AT KCMX THROUGH MUCH OF
THE TAF PERIOD. EXPECT MODERATE SNOW TO CONTINUE THROUGH THE
AFTERNOON AND WITH THE GUSTY WEST-NORTHWEST WINDS...IT SHOULD
COMBINE WITH BLOWING SNOW TO PRODUCE IFR AND OCCASIONAL LIFR
VISIBILITIES THROUGH THE AFTERNOON. AS WINDS SHIFT TO THE SOUTHWEST
THIS EVENING...EXPECT A STRONG BAND TO DEVELOP ON THE ENHANCED
CONVERGENCE AND IMPACT THE SITE AROUND 00Z AND CONTINUE THROUGH THE
EVENING. THERE IS A LITTLE UNCERTAINTY ON HOW FAR NORTH IT WILL
LIFT...BUT LATEST INDICATIONS ARE THE BAND WILL MOVE NORTH OF THE
TAF SITE FOR A PERIOD AND HAVE TRENDED THAT WAY IN THE TAF. AS
WINDS SHIFT TO THE NORTHWEST THURSDAY MORNING...LIGHT TO MODERATE
LAKE EFFECT SNOW WILL MOVE BACK INTO THE SITE.
FOR KSAW/KIWD...THE UNFAVORABLE WIND DIRECTIONS FOR THE SITE WILL
LEAD TO GENERALLY VFR CONDITIONS. GUSTY WINDS AT KIWD HAS BEEN
PRODUCING BLSN AND HAVE MENTIONED MVFR VISIBILITIES TO ACCOUNT FOR
THAT THIS AFTERNOON. THERE ARE SOME HINTS OF INCREASING CLOUDS AND
POTENTIAL MVFR CEILINGS AT KIWD LATE TONIGHT INTO THURSDAY
MORNING WITH A WEAK DISTURBANCE MOVING THROUGH...BUT CONFIDENCE WAS
TOO LOW TO INCLUDE AT THIS POINT.
&&
.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...SRF
MARINE...SRF
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
408 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 THROUGH TUESDAY)
ISSUED AT 549 AM EST WED DEC 11 2013
MAIN LONG TERM FORECAST CONCERNS FOCUS ON CONTINUED COLD WEATHER AND
PERSISTENT...THOUGH...GENERALLY DIMINISHING LAKE EFFECT SNOWS
THURSDAY INTO FRIDAY...THEN SOME SYSTEM SNOW ARRIVING SAT AND SAT
NIGHT WITH PASSAGE OF SHORTWAVE/INVERTED TROUGH...AND FINALLY
ANOTHER BLAST OF ARCTIC AIR IN THE WAKE OF THE TROUGH RESULTING IN
MORE LES LATE SAT NIGHT INTO SUN NIGHT.
THURSDAY...THE AIRMASS MODERATES SOME AS BETTER WAA KICKS IN MAINLY
SOUTH OF THE AREA...ALTHOUGH SOME WEAK ISENTROPIC LIFT ASSOC MAY
PRODUCE A FEW DUSTING OF LIGHT SNOW/FLURRIES THURSDAY MORNING ALONG
THE WI BORDER. INITIAL DRYNESS OF AIRMASS AND WEAK SUPPORT SHOULD
GENERALLY LIMIT MOST PRECIPITATION FROM REACHING THE GROUND. THE
PASSAGE OF THE MID-LEVEL TROUGH AXIS AND Q-VECT DIV AND ASSOC
DRYING/SUBSIDENCE BEHIND IT MAY BE ENOUGH TO FINALLY DISRUPT AND
WEAKEN LES BANDS OVER THE KEWEENAW AND FAR ERN SHORELINE OF THE CWA
BY THE AFTERNOON HRS. LES BANDS WILL LIKELY BE PUSHED OFFSHORE OF
ERN COUNTIES EARLY IN THE MORNING BY DEVELOPING WAA SW FLOW.
INCREASING SW WINDS WILL ALSO LEAD TO BITTER COLD WIND CHILLS OF 20
TO 30 BELOW THU MORNING WARRANTING WIND CHILL ADVISORIES FOR MUCH OF
WRN HALF INTERIOR. EXPECT GREATEST SNOWFALL (UP TO 4 INCHES) OVER
THE KEWEENAW AND ESPECIALLY NEAR HOUGHTON IN CONVERGENT WRLY FLOW.
THU NIGHT INTO FRIDAY...WINDS VEERING FM WNW THU EVENING TO MORE
NRLY BY FRI MORNING IN WAKE OF ANOTHER CLIPPER SYSTEM AND ARCTIC
FRONTAL PASSAGE WILL BRING LES BACK ONSHORE ACROSS MUCH OF THE NRN
CWA. INCREASED LOW-LVL CONVERGENCE OVER ERN LAKE SUPERIOR DUE TO
CONVERGING LAND BREEZES MAY ALLOW A MODERATE LES BAND OR TWO TO SET
UP OVER THE ERN COUNTIES THU NIGHT IN CONVERGENT NW-NNW FLOW.
ELSEWHERE...LACK OF GOOD LOW-LVL CONVERGENCE AND ADVECTION OF DRIER
AIR FROM NORTH OF LAKE BENEATH LOWERING INVERSION HGTS AS NOTED ON
GFS BUFR SNDGS SHOULD GREATLY LIMIT LES INTENSITY AND THUS ACCUMS.
BY FRI AFTERNOON ANY REMAINING LES SHOULD BE QUICKLY DIMINISHING AS
SFC-8H FLOW BCMS SHARPLY ANTICYCLONIC.
FRI NIGHT INTO SATURDAY...WINDS ARE EXPECTED TO GRADUALLY VEER FROM
NORTH FRI EVENING TO EAST BY SATURDAY MORNING AS SFC HIGH PRESSURE
BUILDING DOWN FROM MANITOBA AND WRN ONTARIO SLIDES NORTH OF LAKE
SUPERIOR AND INTO ERN ONTARIO BY 12Z SAT. DEVELOPING NE AND THEN
ERLY FLOW WILL SHIFT INTO REMAINING LIGHT LES OVER LAKE SUPERIOR
INTO THE NW PORTION OF THE CWA. SOME LES COULD ALSO DEVELOP OVER THE
SRN HALF OF MNM COUNTY IN NE-E FLOW WITH LIGHT ACCUMS POSSIBLE.
MODERATE TO DEEP 700-300 MB Q-VECT CONV MOVING ACROSS THE AREA ON
SATURDAY AHEAD OF THE NEXT CLIPPER SHORTWAVE DIVING DOWN FROM
MANITOBA WRN ONTARIO WILL SPREAD LIGHT SNOW ACROSS MUCH OF THE AREA
ESPECIALLY SATURDAY AFTERNOON. INITIAL DRYNESS OF AIRMASS MAY DELAY
ONSET OF SNOW AND LIMIT ACCUMS...FOR THAT REASON ONLY HAVE CHC POPS
FOR NOW ACROSS CWA.
SATURDAY NIGHT INTO SUNDAY NIGHT...MODELS INDICATE MODERATE TO STRONG
Q-VECT CONV AHEAD OF VIGOROUS CLIPPER SHORTWAVE. ENHANCEMENT FROM
SHORTWAVE COMBINED WITH ANOTHER BLAST OF COLD ARCTIC AIR BEHIND IT
WILL LIKELY RESULT IN ANOTHER BOUT OF MODERATE TO HEAVY LAKE
ENHANCED SNOW FOR NORTHWEST AND NORTHEAST UPPER MI LATE SAT NIGHT
INTO SUNDAY AS WIND SHIFTS NW IN THE WAKE OF THE CLIPPER SYSTEM.
STRONGLY CONVERGENT NW FLOW FCST TO DEVELOP OVER ERN LAKE SUPERIOR
WILL LIKELY FAVOR ERN COUNTIES FOR HIGHEST ACCUMS. PASSAGE OF LAKE
ENHANCED TROUGH WILL SHIFT WINDS TO NNE AND PUSH HEAVIER LAKE SNOW
INTO NORTH CENTRAL UPPER MI LATE SUNDAY. SFC HIGH PRESSURE BUILDING
OVER THE REGION WILL WEAKEN WINDS AND QUICKLY DIMINISH ANY REMAINING
LES OVER THE NRN PORTION OF THE CWA.
MONDAY AND TUESDAY...MODELS SHOW SIGNIFICANT DIFFERENCES IN HANDLING
OF NEXT CLIPPER SHORTWAVE DIVING DOWN INTO THE UPPER GREAT LAKES FOR
EARLY NEXT WEEK. THE ECMWF IS DEEPER WITH THIS FEATURE THAN THE GFS
AND ADVANCES IT QUICKER INTO THE REGION. IF THE ECMWF PANS OUT WAA
SSW FLOW AND ENHANCEMENT ASSOC AHEAD OF THE SYSTEM COULD BRING IN
SOME MODERATE TO BRIEFLY HEAVY LES INTO SE AND FAR ERN COUNTIES OF
THE CWA MON AFTERNOON INTO MON EVENING. WINDS VEERING WNW BEHIND THE
CLIPPER WILL BRING BACK LES INTO NW AND NE PORTIONS OF UPPER MI MON
NIGHT INTO TUESDAY.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z THURSDAY AFTERNOON)
ISSUED AT 100 PM EST WED DEC 11 2013
LAKE EFFECT SNOW IS EXPECTED TO CONTINUE AT KCMX THROUGH MUCH OF
THE TAF PERIOD. EXPECT MODERATE SNOW TO CONTINUE THROUGH THE
AFTERNOON AND WITH THE GUSTY WEST-NORTHWEST WINDS...IT SHOULD
COMBINE WITH BLOWING SNOW TO PRODUCE IFR AND OCCASIONAL LIFR
VISIBILITIES THROUGH THE AFTERNOON. AS WINDS SHIFT TO THE SOUTHWEST
THIS EVENING...EXPECT A STRONG BAND TO DEVELOP ON THE ENHANCED
CONVERGENCE AND IMPACT THE SITE AROUND 00Z AND CONTINUE THROUGH THE
EVENING. THERE IS A LITTLE UNCERTAINTY ON HOW FAR NORTH IT WILL
LIFT...BUT LATEST INDICATIONS ARE THE BAND WILL MOVE NORTH OF THE
TAF SITE FOR A PERIOD AND HAVE TRENDED THAT WAY IN THE TAF. AS
WINDS SHIFT TO THE NORTHWEST THURSDAY MORNING...LIGHT TO MODERATE
LAKE EFFECT SNOW WILL MOVE BACK INTO THE SITE.
FOR KSAW/KIWD...THE UNFAVORABLE WIND DIRECTIONS FOR THE SITE WILL
LEAD TO GENERALLY VFR CONDITIONS. GUSTY WINDS AT KIWD HAS BEEN
PRODUCING BLSN AND HAVE MENTIONED MVFR VISIBILITIES TO ACCOUNT FOR
THAT THIS AFTERNOON. THERE ARE SOME HINTS OF INCREASING CLOUDS AND
POTENTIAL MVFR CEILINGS AT KIWD LATE TONIGHT INTO THURSDAY
MORNING WITH A WEAK DISTURBANCE MOVING THROUGH...BUT CONFIDENCE WAS
TOO LOW TO INCLUDE AT THIS POINT.
&&
.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...VOSS
AVIATION...SRF
MARINE...SRF
AREA FORECAST DISCUSSION
NWS GRAND RAPIDS MI
227 PM EST WED DEC 11 2013
LATEST UPDATE...
UPDATE
.SYNOPSIS...
ISSUED AT 327 AM EST WED DEC 11 2013
COLD AND SNOWY WEATHER WILL CONTINUE THROUGH THE REST OF THE WEEK
AND WEEKEND. A BURST OF HEAVIER SNOW IS ON THE WAY TO AREAS NEAR TO
MAINLY SOUTH OF INTERSTATE 96 FROM AROUND DAYBREAK THROUGH THE REST
OF THE MORNING INTO THE EARLY TO MID AFTERNOON HOURS. ANOTHER BURST
OF HEAVIER LAKE EFFECT SNOW WILL OCCUR THURSDAY FROM HOLLAND
NORTHWARD AS WINDS BACK TO THE SOUTHWEST. LOW PRESSURE WILL BRING
MORE SNOW SATURDAY WITH SEVERAL MORE ROUNDS OF SNOW EXPECTED LATE IN
THE WEEKEND INTO EARLY NEXT WEEK.
&&
.UPDATE...
ISSUED AT 226 PM EST WED DEC 11 2013
WITH THE HIGHER REFLECTIVITIES NOW SOUTH OF THE AREA FOR THE MOST
PART AND SOME SUN AT TIMES HAVE DROPPED THE WINTER WEATHER
ADVISORY. ROADS WILL CONTINUE TO BE SLIPPERY IN SPOTS AS COLD AIR
TEMPS...DROPPING INTO THE SINGLE DIGITS IN QUITE A FEW AREAS THIS
EVENING...MAKE ROAD SALT LESS EFFECTIVE. WIND CHILL VALUES WILL
DIP TO AROUND ZERO F THIS EVENING. LAKE EFFECT SNOW SHOWERS WILL
CONTINUE THIS EVENING...BUT NOT EXPECTING SIGNIFICANT
ACCUMULATIONS.
&&
.SHORT TERM...(TODAY THROUGH FRIDAY AFTERNOON)
ISSUED AT 327 AM EST WED DEC 11 2013
A CONSENSUS OF HIGHER RESOLUTION SHORT RANGE GUIDANCE INCLUDING THE
RUC... HRRR AND 4KM WRF NMM ALL INDICATE THAT ANOTHER BURST OF
HEAVIER SNOW WILL DEVELOP NEAR TO MAINLY SOUTH OF INTERSTATE 96
DURING THE EARLY TO MID MORNING HOURS. THE HEAVIEST SNOW WILL LINGER
THROUGH AT LEAST EARLY AFTERNOON BEFORE TAPERING OFF. A COUPLE OF
UPPER LEVEL DISTURBANCES MOVING THROUGH LATER THIS MORNING INTO THE
AFTERNOON WILL ENHANCE THE SNOW WITH DEEP LOW TO MID LEVEL MOISTURE
IN PLACE THROUGH 18Z THIS AFTERNOON AND WITH H8 TEMPS WAY DOWN
AROUND -16 TO -18 C.
HEAVIEST SNOW FROM MID MORNING THROUGH EARLY TO MID AFTERNOON WILL
FALL MAINLY SOUTH OF I-96 WITH ABOUT 3 TO 5 INCHES OF SNOW EXPECTED
DOWN AROUND HASTINGS... ALLEGAN... SOUTH HAVEN AND KALAMAZOO. A
BUKFIT X-SECTION FOR SOUTH HAVEN SHOWS ABOUT 10 MICROBARS/SEC OF
LIFT LATE THIS MORNING WITH INVERSION HEIGHTS UP AROUND 8-9 KFT. OUR
ONGOING WINTER WEATHER HEADLINES LOOK EXCELLENT AND WILL REMAIN
UNCHANGED.
WNW TO WEST FLOW LES WILL CONTINUE TONIGHT WITH SUFFICIENT MOISTURE
STILL IN PLACE AND H8 TEMPS STILL DOWN AROUND -16 TO -18 C. THEN
WINDS WILL BACK TO THE WSW TO SW THURSDAY FAVORING AREAS FROM AROUND
BIV NORTHWARD OVER OUR NW FCST AREA TO RECEIVE SEVERAL INCHES OF
LAKE EFFECT. LAKE EFFECT SNOW SHOWERS SHOULD FINALLY WIND DOWN A BIT
THURSDAY NIGHT AS H8 TEMPS SLOWLY MODERATE. ONLY A SMALL CHANCE FOR
LIGHT SNOW SHOWERS FRIDAY SINCE BY THEN SFC WINDS SHOULD BECOME
EASTERLY.
.LONG TERM...(FRIDAY NIGHT THROUGH TUESDAY)
ISSUED AT 327 AM EST WED DEC 11 2013
LIKELY POPS STILL LOOKS GOOD FOR SATURDAY AS THE 00Z GUIDANCE HAS
MAINTAINED CONTINUITY WITH THE LOW COMING OUT OF THE SOUTHERN
PLAINS. MID LEVEL F-GEN COULD BE STRONG ENOUGH TO PRODUCE MESOSCALE
BANDS OF LIGHT TO MODERATE SNOW FOR SEVERAL HOURS SATURDAY AFTERNOON
AND EVENING ACROSS CENTRAL AND SOUTHERN LOWER MICHIGAN.
THE LOW MOVES EAST SATURDAY NIGHT...BUT LOWER MICHIGAN REMAINS IN
THE TROWAL INTO SUNDAY. SO THE SNOW WILL LESSEN IN INTENSITY BUT NOT
END AS AN ARCTIC FRONT PROVIDES SFC CONVERGENCE INTO SUNDAY NIGHT.
SFC RIDGING SHOULD BUILD IN LATE SUNDAY NIGHT THEN RETURN FLOW
FOLLOWS FOR MONDAY IN ADVANCE OF NEXT CLIPPER. SNOW TAPERS OFF
MONDAY BEFORE WARM ADVECTION SNOWS BREAK OUT MONDAY NIGHT FOLLOWED
BY LAKE ENHANCED SNOW SHOWERS FOR TUESDAY.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z THURSDAY AFTERNOON)
ISSUED AT 1257 PM EST WED DEC 11 2013
WIDESPREAD LAKE EFFECT SNOW SHOWERS ARE DIMINISHING IN COVERAGE
AND INTENSITY EARLY THIS AFTERNOON...AND ARE EXPECTED TO CONTINUE
TO DO SO THE REST OF THE DAY. SOME POCKETS OF IFR WILL REMAIN
CLOSER TO THE LAKESHORE UNDER THE ISOLATED HEAVIER SNOW SHOWERS
STILL EXPECTED. THE REST OF THE AREA WILL SEE VFR/MVFR CONDITIONS
IN LESS COVERAGE OF SNOW SHOWERS.
LAKE EFFECT SNOW SHOWERS SHOULD MIGRATE BACK CLOSER TO THE
LAKESHORE TONIGHT BASED ON THE LATEST VISIBLE SATELLITE TRENDS. WE
ARE EXPECTING CLEARING TO TAKE PLACE INLAND...WITH LIGHT SNOW
SHOWERS ALONG THE LAKESHORE. MVFR WILL BE LIKELY ALONG THE
LAKESHORE AND MAINLY VFR INLAND.
SNOW SHOWERS WILL BEGIN TO PICK UP IN COVERAGE AND INTENSITY FOR A
FEW HOURS ON THU MORNING AS ANOTHER WAVE MOVES THROUGH. SNOW
SHOWERS WILL SPREAD INLAND ON W/SW FLOW AND DIURNAL PROCESSES.
MVFR CONDITIONS WILL BECOME DOMINANT WITH SOME IFR POSSIBLE NEAR
KMKG AND KGRR.
&&
.MARINE...
ISSUED AT 327 AM EST WED DEC 11 2013
A SMALL CRAFT ADVISORY HAS BEEN ISSUED FOR TODAY THROUGH EARLY
THURSDAY EVENING AS BRISK WEST NORTHWEST WINDS WILL RESULT IN WAVE
HEIGHTS GENERALLY AROUND 4 TO 7 FEET TODAY AND TONIGHT. WINDS
THURSDAY WILL BACK TO THE SOUTHWEST AT 15 TO 25 KNOTS RESULTING IN
CONTINUED SIGNIFICANT WAVE ACTION.
&&
.HYDROLOGY...
ISSUED AT 327 AM EST WED DEC 11 2013
TEMPERATURES WILL REMAIN WELL BELOW NORMAL THROUGH THE REST OF THE
WEEK AND WEEKEND ALONG WITH SEVERAL ROUNDS OF SNOW SHOWERS. THIS
COMBINATION OF SNOW AND COLD TEMPERATURES WILL RESULT IN POTENTIAL
FOR ICE JAM FORMATION. SO WE WILL CONTINUE TO MONITOR RIVER LEVELS
CLOSELY.
&&
.GRR WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LM...SMALL CRAFT ADVISORY UNTIL 7 PM EST THURSDAY FOR LMZ844>849.
&&
$$
UPDATE...DUKE
SYNOPSIS...LAURENS
SHORT TERM...LAURENS
LONG TERM...OSTUNO
AVIATION...NJJ
HYDROLOGY...LAURENS
MARINE...LAURENS
AREA FORECAST DISCUSSION
NWS GRAND RAPIDS MI
1258 PM EST WED DEC 11 2013
LATEST UPDATE...
AVIATION
.SYNOPSIS...
ISSUED AT 327 AM EST WED DEC 11 2013
COLD AND SNOWY WEATHER WILL CONTINUE THROUGH THE REST OF THE WEEK
AND WEEKEND. A BURST OF HEAVIER SNOW IS ON THE WAY TO AREAS NEAR TO
MAINLY SOUTH OF INTERSTATE 96 FROM AROUND DAYBREAK THROUGH THE REST
OF THE MORNING INTO THE EARLY TO MID AFTERNOON HOURS. ANOTHER BURST
OF HEAVIER LAKE EFFECT SNOW WILL OCCUR THURSDAY FROM HOLLAND
NORTHWARD AS WINDS BACK TO THE SOUTHWEST. LOW PRESSURE WILL BRING
MORE SNOW SATURDAY WITH SEVERAL MORE ROUNDS OF SNOW EXPECTED LATE IN
THE WEEKEND INTO EARLY NEXT WEEK.
&&
.UPDATE...
ISSUED AT 1131 AM EST WED DEC 11 2013
DROPPING MUSKEGON...OCEANA AND MASON FROM THE WINTER WEATHER
ADVISORY WITH THE REST REMAINING IN PLACE THROUGH THE AFTERNOON.
FEELING IS THE REMAINING COUNTIES WILL BE ABLE TO BE DROPPED IN
THE EARLY AFTERNOON AS WELL. WANT TO LET SOME OF THE HIGHER
REFLECTIVITIES DROP SOUTH OF THE AREA ASSOCIATED WITH THE BETTER
BANDING BEFORE ENDING IT. THAT WILL LIKELY TAKE PLACE IN THE 1-2 PM
TIME FRAME. ROADS ARE STILL NOT IN GOOD SHAPE GIVEN THE FINE SNOW
FLAKES LEADING TO FAIRLY GREASY ROADS THIS MORNING. ADVISORY IN
TERMS OF IMPACT SEEMED TO WORK OUT WELL GIVEN LIMITED VISIBILITIES
THIS MORNING AND POOR ROAD CONDITIONS. HIGHWAY 131 SOUTH OF GRAND
RAPIDS PER THE MDOT TRAVEL SPEEDS PAGE AS BEEN IMPACTED ALL
MORNING AND CONTINUES TO BE AFFECTED WITH A SECTION STILL SHUT
DOWN IT APPEARS. AGAIN...EARLY TO MID AFTERNOON FEEL WE WILL BE
ABLE TO END THE REMAINING PORTION OF THE WINTER WEATHER ADVISORY
EARLY. SOME LOCAL ACCUMULATIONS OF AN INCH OR SO WILL REMAIN
POSSIBLE THIS AFTERNOON. BEST CHANCE OF THIS OCCURRING THROUGH 00Z
WILL BE FROM OTTAWA COUNTY SOUTH DOWN THE SHORE.
&&
.SHORT TERM...(TODAY THROUGH FRIDAY AFTERNOON)
ISSUED AT 327 AM EST WED DEC 11 2013
A CONSENSUS OF HIGHER RESOLUTION SHORT RANGE GUIDANCE INCLUDING THE
RUC... HRRR AND 4KM WRF NMM ALL INDICATE THAT ANOTHER BURST OF
HEAVIER SNOW WILL DEVELOP NEAR TO MAINLY SOUTH OF INTERSTATE 96
DURING THE EARLY TO MID MORNING HOURS. THE HEAVIEST SNOW WILL LINGER
THROUGH AT LEAST EARLY AFTERNOON BEFORE TAPERING OFF. A COUPLE OF
UPPER LEVEL DISTURBANCES MOVING THROUGH LATER THIS MORNING INTO THE
AFTERNOON WILL ENHANCE THE SNOW WITH DEEP LOW TO MID LEVEL MOISTURE
IN PLACE THROUGH 18Z THIS AFTERNOON AND WITH H8 TEMPS WAY DOWN
AROUND -16 TO -18 C.
HEAVIEST SNOW FROM MID MORNING THROUGH EARLY TO MID AFTERNOON WILL
FALL MAINLY SOUTH OF I-96 WITH ABOUT 3 TO 5 INCHES OF SNOW EXPECTED
DOWN AROUND HASTINGS... ALLEGAN... SOUTH HAVEN AND KALAMAZOO. A
BUKFIT X-SECTION FOR SOUTH HAVEN SHOWS ABOUT 10 MICROBARS/SEC OF
LIFT LATE THIS MORNING WITH INVERSION HEIGHTS UP AROUND 8-9 KFT. OUR
ONGOING WINTER WEATHER HEADLINES LOOK EXCELLENT AND WILL REMAIN
UNCHANGED.
WNW TO WEST FLOW LES WILL CONTINUE TONIGHT WITH SUFFICIENT MOISTURE
STILL IN PLACE AND H8 TEMPS STILL DOWN AROUND -16 TO -18 C. THEN
WINDS WILL BACK TO THE WSW TO SW THURSDAY FAVORING AREAS FROM AROUND
BIV NORTHWARD OVER OUR NW FCST AREA TO RECEIVE SEVERAL INCHES OF
LAKE EFFECT. LAKE EFFECT SNOW SHOWERS SHOULD FINALLY WIND DOWN A BIT
THURSDAY NIGHT AS H8 TEMPS SLOWLY MODERATE. ONLY A SMALL CHANCE FOR
LIGHT SNOW SHOWERS FRIDAY SINCE BY THEN SFC WINDS SHOULD BECOME
EASTERLY.
.LONG TERM...(FRIDAY NIGHT THROUGH TUESDAY)
ISSUED AT 327 AM EST WED DEC 11 2013
LIKELY POPS STILL LOOKS GOOD FOR SATURDAY AS THE 00Z GUIDANCE HAS
MAINTAINED CONTINUITY WITH THE LOW COMING OUT OF THE SOUTHERN
PLAINS. MID LEVEL F-GEN COULD BE STRONG ENOUGH TO PRODUCE MESOSCALE
BANDS OF LIGHT TO MODERATE SNOW FOR SEVERAL HOURS SATURDAY AFTERNOON
AND EVENING ACROSS CENTRAL AND SOUTHERN LOWER MICHIGAN.
THE LOW MOVES EAST SATURDAY NIGHT...BUT LOWER MICHIGAN REMAINS IN
THE TROWAL INTO SUNDAY. SO THE SNOW WILL LESSEN IN INTENSITY BUT NOT
END AS AN ARCTIC FRONT PROVIDES SFC CONVERGENCE INTO SUNDAY NIGHT.
SFC RIDGING SHOULD BUILD IN LATE SUNDAY NIGHT THEN RETURN FLOW
FOLLOWS FOR MONDAY IN ADVANCE OF NEXT CLIPPER. SNOW TAPERS OFF
MONDAY BEFORE WARM ADVECTION SNOWS BREAK OUT MONDAY NIGHT FOLLOWED
BY LAKE ENHANCED SNOW SHOWERS FOR TUESDAY.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z THURSDAY AFTERNOON)
ISSUED AT 1257 PM EST WED DEC 11 2013
WIDESPREAD LAKE EFFECT SNOW SHOWERS ARE DIMINISHING IN COVERAGE
AND INTENSITY EARLY THIS AFTERNOON...AND ARE EXPECTED TO CONTINUE
TO DO SO THE REST OF THE DAY. SOME POCKETS OF IFR WILL REMAIN
CLOSER TO THE LAKESHORE UNDER THE ISOLATED HEAVIER SNOW SHOWERS
STILL EXPECTED. THE REST OF THE AREA WILL SEE VFR/MVFR CONDITIONS
IN LESS COVERAGE OF SNOW SHOWERS.
LAKE EFFECT SNOW SHOWERS SHOULD MIGRATE BACK CLOSER TO THE
LAKESHORE TONIGHT BASED ON THE LATEST VISIBLE SATELLITE TRENDS. WE
ARE EXPECTING CLEARING TO TAKE PLACE INLAND...WITH LIGHT SNOW
SHOWERS ALONG THE LAKESHORE. MVFR WILL BE LIKELY ALONG THE
LAKESHORE AND MAINLY VFR INLAND.
SNOW SHOWERS WILL BEGIN TO PICK UP IN COVERAGE AND INTENSITY FOR A
FEW HOURS ON THU MORNING AS ANOTHER WAVE MOVES THROUGH. SNOW
SHOWERS WILL SPREAD INLAND ON W/SW FLOW AND DIURNAL PROCESSES.
MVFR CONDITIONS WILL BECOME DOMINANT WITH SOME IFR POSSIBLE NEAR
KMKG AND KGRR.
&&
.MARINE...
ISSUED AT 327 AM EST WED DEC 11 2013
A SMALL CRAFT ADVISORY HAS BEEN ISSUED FOR TODAY THROUGH EARLY
THURSDAY EVENING AS BRISK WEST NORTHWEST WINDS WILL RESULT IN WAVE
HEIGHTS GENERALLY AROUND 4 TO 7 FEET TODAY AND TONIGHT. WINDS
THURSDAY WILL BACK TO THE SOUTHWEST AT 15 TO 25 KNOTS RESULTING IN
CONTINUED SIGNIFICANT WAVE ACTION.
&&
.HYDROLOGY...
ISSUED AT 327 AM EST WED DEC 11 2013
TEMPERATURES WILL REMAIN WELL BELOW NORMAL THROUGH THE REST OF THE
WEEK AND WEEKEND ALONG WITH SEVERAL ROUNDS OF SNOW SHOWERS. THIS
COMBINATION OF SNOW AND COLD TEMPERATURES WILL RESULT IN POTENTIAL
FOR ICE JAM FORMATION. SO WE WILL CONTINUE TO MONITOR RIVER LEVELS
CLOSELY.
&&
.GRR WATCHES/WARNINGS/ADVISORIES...
MI...WINTER WEATHER ADVISORY UNTIL 5 PM EST THIS AFTERNOON FOR MIZ056-
057-064>066-071>073.
LM...SMALL CRAFT ADVISORY UNTIL 7 PM EST THURSDAY FOR LMZ844>849.
&&
$$
UPDATE...DUKE
SYNOPSIS...LAURENS
SHORT TERM...LAURENS
LONG TERM...OSTUNO
AVIATION...NJJ
HYDROLOGY...LAURENS
MARINE...LAURENS
AREA FORECAST DISCUSSION
NWS GRAND RAPIDS MI
1139 AM EST WED DEC 11 2013
LATEST UPDATE...
UPDATE
.SYNOPSIS...
ISSUED AT 327 AM EST WED DEC 11 2013
COLD AND SNOWY WEATHER WILL CONTINUE THROUGH THE REST OF THE WEEK
AND WEEKEND. A BURST OF HEAVIER SNOW IS ON THE WAY TO AREAS NEAR TO
MAINLY SOUTH OF INTERSTATE 96 FROM AROUND DAYBREAK THROUGH THE REST
OF THE MORNING INTO THE EARLY TO MID AFTERNOON HOURS. ANOTHER BURST
OF HEAVIER LAKE EFFECT SNOW WILL OCCUR THURSDAY FROM HOLLAND
NORTHWARD AS WINDS BACK TO THE SOUTHWEST. LOW PRESSURE WILL BRING
MORE SNOW SATURDAY WITH SEVERAL MORE ROUNDS OF SNOW EXPECTED LATE IN
THE WEEKEND INTO EARLY NEXT WEEK.
&&
.UPDATE...
ISSUED AT 1131 AM EST WED DEC 11 2013
DROPPING MUSKEGON...OCEANA AND MASON FROM THE WINTER WEATHER
ADVISORY WITH THE REST REMAINING IN PLACE THROUGH THE AFTERNOON.
FEELING IS THE REMAINING COUNTIES WILL BE ABLE TO BE DROPPED IN
THE EARLY AFTERNOON AS WELL. WANT TO LET SOME OF THE HIGHER
REFLECTIVITIES DROP SOUTH OF THE AREA ASSOCIATED WITH THE BETTER
BANDING BEFORE ENDING IT. THAT WILL LIKELY TAKE PLACE IN THE 1-2 PM
TIME FRAME. ROADS ARE STILL NOT IN GOOD SHAPE GIVEN THE FINE SNOW
FLAKES LEADING TO FAIRLY GREASY ROADS THIS MORNING. ADVISORY IN
TERMS OF IMPACT SEEMED TO WORK OUT WELL GIVEN LIMITED VISIBILITIES
THIS MORNING AND POOR ROAD CONDITIONS. HIGHWAY 131 SOUTH OF GRAND
RAPIDS PER THE MDOT TRAVEL SPEEDS PAGE AS BEEN IMPACTED ALL
MORNING AND CONTINUES TO BE AFFECTED WITH A SECTION STILL SHUT
DOWN IT APPEARS. AGAIN...EARLY TO MID AFTERNOON FEEL WE WILL BE
ABLE TO END THE REMAINING PORTION OF THE WINTER WEATHER ADVISORY
EARLY. SOME LOCAL ACCUMULATIONS OF AN INCH OR SO WILL REMAIN
POSSIBLE THIS AFTERNOON. BEST CHANCE OF THIS OCCURRING THROUGH 00Z
WILL BE FROM OTTAWA COUNTY SOUTH DOWN THE SHORE.
&&
.SHORT TERM...(TODAY THROUGH FRIDAY AFTERNOON)
ISSUED AT 327 AM EST WED DEC 11 2013
A CONSENSUS OF HIGHER RESOLUTION SHORT RANGE GUIDANCE INCLUDING THE
RUC... HRRR AND 4KM WRF NMM ALL INDICATE THAT ANOTHER BURST OF
HEAVIER SNOW WILL DEVELOP NEAR TO MAINLY SOUTH OF INTERSTATE 96
DURING THE EARLY TO MID MORNING HOURS. THE HEAVIEST SNOW WILL LINGER
THROUGH AT LEAST EARLY AFTERNOON BEFORE TAPERING OFF. A COUPLE OF
UPPER LEVEL DISTURBANCES MOVING THROUGH LATER THIS MORNING INTO THE
AFTERNOON WILL ENHANCE THE SNOW WITH DEEP LOW TO MID LEVEL MOISTURE
IN PLACE THROUGH 18Z THIS AFTERNOON AND WITH H8 TEMPS WAY DOWN
AROUND -16 TO -18 C.
HEAVIEST SNOW FROM MID MORNING THROUGH EARLY TO MID AFTERNOON WILL
FALL MAINLY SOUTH OF I-96 WITH ABOUT 3 TO 5 INCHES OF SNOW EXPECTED
DOWN AROUND HASTINGS... ALLEGAN... SOUTH HAVEN AND KALAMAZOO. A
BUKFIT X-SECTION FOR SOUTH HAVEN SHOWS ABOUT 10 MICROBARS/SEC OF
LIFT LATE THIS MORNING WITH INVERSION HEIGHTS UP AROUND 8-9 KFT. OUR
ONGOING WINTER WEATHER HEADLINES LOOK EXCELLENT AND WILL REMAIN
UNCHANGED.
WNW TO WEST FLOW LES WILL CONTINUE TONIGHT WITH SUFFICIENT MOISTURE
STILL IN PLACE AND H8 TEMPS STILL DOWN AROUND -16 TO -18 C. THEN
WINDS WILL BACK TO THE WSW TO SW THURSDAY FAVORING AREAS FROM AROUND
BIV NORTHWARD OVER OUR NW FCST AREA TO RECEIVE SEVERAL INCHES OF
LAKE EFFECT. LAKE EFFECT SNOW SHOWERS SHOULD FINALLY WIND DOWN A BIT
THURSDAY NIGHT AS H8 TEMPS SLOWLY MODERATE. ONLY A SMALL CHANCE FOR
LIGHT SNOW SHOWERS FRIDAY SINCE BY THEN SFC WINDS SHOULD BECOME
EASTERLY.
.LONG TERM...(FRIDAY NIGHT THROUGH TUESDAY)
ISSUED AT 327 AM EST WED DEC 11 2013
LIKELY POPS STILL LOOKS GOOD FOR SATURDAY AS THE 00Z GUIDANCE HAS
MAINTAINED CONTINUITY WITH THE LOW COMING OUT OF THE SOUTHERN
PLAINS. MID LEVEL F-GEN COULD BE STRONG ENOUGH TO PRODUCE MESOSCALE
BANDS OF LIGHT TO MODERATE SNOW FOR SEVERAL HOURS SATURDAY AFTERNOON
AND EVENING ACROSS CENTRAL AND SOUTHERN LOWER MICHIGAN.
THE LOW MOVES EAST SATURDAY NIGHT...BUT LOWER MICHIGAN REMAINS IN
THE TROWAL INTO SUNDAY. SO THE SNOW WILL LESSEN IN INTENSITY BUT NOT
END AS AN ARCTIC FRONT PROVIDES SFC CONVERGENCE INTO SUNDAY NIGHT.
SFC RIDGING SHOULD BUILD IN LATE SUNDAY NIGHT THEN RETURN FLOW
FOLLOWS FOR MONDAY IN ADVANCE OF NEXT CLIPPER. SNOW TAPERS OFF
MONDAY BEFORE WARM ADVECTION SNOWS BREAK OUT MONDAY NIGHT FOLLOWED
BY LAKE ENHANCED SNOW SHOWERS FOR TUESDAY.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z THURSDAY MORNING)
ISSUED AT 643 AM EST WED DEC 11 2013
MVFR AND IFR IN SNOW AND BLOWING SNOW THIS MORNING WILL IMPROVE TO
MVFR AND VFR BY 18Z FOR MOST PLACES. THE HEAVIER SNOW WILL BE
AROUND AZO WHERE IFR WILL BE PREVAILING MUCH OF THE MORNING. WINDS
WILL BE WEST AROUND 10 TO 15 KNOTS THIS MORNING GOING NORTHWEST
THIS AFTERNOON.
&&
.MARINE...
ISSUED AT 327 AM EST WED DEC 11 2013
A SMALL CRAFT ADVISORY HAS BEEN ISSUED FOR TODAY THROUGH EARLY
THURSDAY EVENING AS BRISK WEST NORTHWEST WINDS WILL RESULT IN WAVE
HEIGHTS GENERALLY AROUND 4 TO 7 FEET TODAY AND TONIGHT. WINDS
THURSDAY WILL BACK TO THE SOUTHWEST AT 15 TO 25 KNOTS RESULTING IN
CONTINUED SIGNIFICANT WAVE ACTION.
&&
.HYDROLOGY...
ISSUED AT 327 AM EST WED DEC 11 2013
TEMPERATURES WILL REMAIN WELL BELOW NORMAL THROUGH THE REST OF THE
WEEK AND WEEKEND ALONG WITH SEVERAL ROUNDS OF SNOW SHOWERS. THIS
COMBINATION OF SNOW AND COLD TEMPERATURES WILL RESULT IN POTENTIAL
FOR ICE JAM FORMATION. SO WE WILL CONTINUE TO MONITOR RIVER LEVELS
CLOSELY.
&&
.GRR WATCHES/WARNINGS/ADVISORIES...
MI...WINTER WEATHER ADVISORY UNTIL 5 PM EST THIS AFTERNOON FOR MIZ056-
057-064>066-071>073.
LM...SMALL CRAFT ADVISORY UNTIL 7 PM EST THURSDAY FOR LMZ844>849.
&&
$$
UPDATE...DUKE
SYNOPSIS...LAURENS
SHORT TERM...LAURENS
LONG TERM...OSTUNO
AVIATION...OSTUNO
HYDROLOGY...LAURENS
MARINE...LAURENS
AREA FORECAST DISCUSSION...UPDATED
NWS BILLINGS MT
909 AM MST WED DEC 11 2013
.UPDATE...
NO SIGNIFICANT CHANGES TO THE FORECAST THIS MORNING. SHOULD BE
MAINLY DRY THROUGH AT LEAST THURSDAY. MAIN WEATHER IMPACT WILL BE
WIND IN THE WESTERN ZONES THE NEXT COUPLE OF DAYS. THIS IS
ALREADY HANDLED WELL BY THE WIND ADVISORY. I DID BUMP UP GUSTS FOR
AREAS AROUND WHEATLAND COUNTY BASED ON RAP MODEL GUIDANCE AND
CURRENT OBSERVATIONS. BT
&&
.SHORT TERM...VALID FOR TDY AND THU...
A REAL WARMING TREND IS IN STORE THE NEXT TWO DAYS UNDER NORTHWEST
FLOW ALOFT...BUT WINDS WILL REMAIN AN ISSUE IN SOUTH CENTRAL MT.
WARM AIR ADVECTION WILL BE ONGOING ALOFT THE NEXT 36 HOURS WITH AN
850-HPA THERMAL RIDGE OF +6 C OVER CENTRAL MT BY THU AFTERNOON. WE
EXPECT MUCH OF THIS WARM AIR TO GO TO WASTE WITH AN EXPANSIVE SNOW
FIELD APT TO LIMIT LOW-LEVEL MIXING...ESPECIALLY IN RIVER VALLEYS.
FORECAST SOUNDINGS BOTH TODAY AND THU SUGGEST MIXING COULD BE HELD
CLOSE TO 1000 FT AGL. EVEN SO...BY THU THE AIR MASS IS WARM ENOUGH
TO YIELD TEMPERATURES WELL INTO THE 30S F IN MOST PLACES EVEN WITH
THAT SHALLOW MIXING. FORECAST HIGHS TODAY AND THU ARE MAINLY BASED
ON THE GUIDANCE WHICH HAS BEEN PERFORMING WELL OVER THE LAST SEVEN
DAYS WHEN OUR SNOW FIELD HAS BEEN IN PLACE...WITH WEIGHTING TOWARD
THE 00 UTC GEM NUMBERS. THERE IS NONETHELESS LOTS OF POTENTIAL FOR
HIGHS TO BE EITHER MUCH WARMER OR COLDER THAN EXPECTED IN SPOTS IF
MIXING IS EITHER DEEPER OR EVEN MORE SHALLOW THAN ANTICIPATED.
AS FAR AS WINDS ARE CONCERNED...A WIND ADVISORY CONTINUES UNTIL 15
UTC FRI FOR THE LIVINGSTON AND NYE AREAS AS A 15 TO 20 HPA SURFACE
PRESSURE GRADIENT WILL EXIST BETWEEN IDAHO FALLS AND LEWISTOWN FOR
MUCH OF THE TIME THROUGH THU NIGHT. WE BELIEVE THE PEAK WINDS WILL
BE TONIGHT WHEN THE GRADIENT IS ESPECIALLY TIGHT AND THE STABILITY
AT MOUNTAIN-TOP LEVEL IS GREATEST. AN UPGRADE TO HIGH WIND WARNING
IS NOT OUT OF THE QUESTION WITH A LATER FORECAST. IN CONTRAST...IT
LOOKS LIKE WINDS MAY START RELAXING THU AFTERNOON AND THU NIGHT AS
SURFACE PRESSURE FALLS BEGIN IN EARNEST OVER SOUTHEAST ID AND OVER
YELLOWSTONE PARK AND AS MID-LEVEL COOLING BEGINS AT LIVINGSTON THU
EVENING. LEE-SIDE PRESSURE FALLS WILL ALSO SUPPORT GUSTY WINDS FOR
THE PLAINS OF SOUTH CENTRAL MT...AND A LOCAL ENHANCEMENT IS LIKELY
NEAR YELLOWTAIL DAM IN THIS PATTERN...WHERE GUSTS TO 55 MPH SHOULD
BE AN EASY ACHIEVEMENT BASED ON CLIMATOLOGY AND 00 UTC NAM OUTPUT.
FINALLY...WE ARE MENTIONING AT LEAST PATCHY BLOWING SNOW TODAY AND
TONIGHT IN PLACES OVER SOUTH CENTRAL MT WITH GUSTY WINDS. SCHULTZ
.LONG TERM...VALID FOR FRI...SAT...SUN...MON...TUE...
FRIDAY WILL BE A COOLER DAY AS A CLIPPER SYSTEM MOVES THROUGH THE
DAKOTAS PUSHING THE ARCTIC BACK INTO THE AREA AND LESS DOWNSLOPE
ACROSS THE WESTERN ZONES. MODELS DIFFER A BIT IN HOW FAR WEST THE
COLD AIR WILL COME SO LIMITED A REAL COOL DOWN INTO THE EASTERN
AREAS. THERE WILL BE A THREAT OF SHOWERS MAINLY FOR OROGRAPHIC
MOUNTAINS AS THE FLOW ALOFT INCREASES MOISTURE AND CANNOT RULE OUT
SOME LIGHT SNOW WITH THE BACKDOOR FRONT.
LEESIDE TROF BEGINS TO REBUILD ON SATURDAY AS THE DEEPEST COLD AIR
HEADS INTO THE MIDWEST. THIS ALLOWS THE ARCTIC TO RETREAT AND
BETTER MIXING ACROSS THE WESTERN ZONES. MODELS ALSO TEMPORARILY
DRY OUT THE FLOW ALOFT SO SHOULD SEE LESS SHOWER ACTIVITY WITH
DOWNSLOPE DEFEATING SHOWERS IN THE CENTRAL ZONES. HEIGHTS BUILDING
OVER SOUTHWESTERN PORTIONS OF THE US STRENGTHEN SURFACE HIGH
PRESSURE WEST OF THE DIVIDE ON SUNDAY WHICH WILL BRING AN
INCREASING THREAT OF GAP FLOW WINDS. THIS WINDIER AND DRY PATTERN
STARTING ON SUNDAY KEEPS GOING INTO MONDAY AND TUESDAY BEFORE A
CHANGE OCCURS SOMETIME IN THE WEDNESDAY TO FRIDAY TIMEFRAME. BOTH
ECMWF AND A SERIES OF GFS RUNS ARE ADVERTISING A STRONG ARCTIC
INTRUSION WITH A FAVORABLE FLOW ALOFT TO GENERATE SNOWFALL. TIMING
VARIES BY 36 HOURS BETWEEN THE MODELS BUT THE MAIN MESSAGE IS THE
DEEP CHILL AND MORE SNOW SHOULD BE EXPECTED LATTER HALF OF NEXT
WEEK. BORSUM
&&
.AVIATION...
STRONG...GUSTY SW WINDS WILL IMPACT KLVM AND OTHER LOCATIONS
ALONG THE WESTERN FOOTHILLS. THESE WINDS WILL GENERATE AREAS OF
BLOWING SNOW REDUCING VISIBILITY TO MVFR LOCALLY AT TIMES.
OTHERWISE...VFR CONDITIONS ARE EXPECTED ACROSS THE REST OF THE
REGION INTO TONIGHT. STC
&&
.PRELIMINARY POINT TEMP/POPS...
TDY THU FRI SAT SUN MON TUE
-------------------------------------------------------
BIL 028 021/037 021/033 017/032 025/037 022/033 017/033
0/N 00/N 12/J 11/E 11/B 10/B 11/B
LVM 029 022/039 020/037 021/035 024/035 021/032 020/031
1/Q 11/N 22/W 12/J 21/N 21/N 11/B
HDN 028 016/035 018/034 014/029 022/035 020/034 016/030
1/B 00/B 12/J 12/J 11/B 10/B 11/B
MLS 024 013/033 013/022 012/021 012/031 020/033 014/025
0/B 11/B 13/J 11/E 32/J 22/J 11/B
4BQ 027 013/036 014/028 014/026 017/032 020/033 015/027
0/B 00/B 02/J 12/J 22/J 11/B 11/B
BHK 022 010/031 008/020 012/016 008/026 018/030 012/023
0/B 11/B 13/J 11/E 33/J 12/J 11/B
SHR 030 015/041 014/033 016/033 018/036 020/034 016/031
1/U 10/B 13/J 12/J 11/B 21/B 11/B
&&
.BYZ WATCHES/WARNINGS/ADVISORIES...
MT...WIND ADVISORY IN EFFECT UNTIL 8 AM MST FRIDAY FOR ZONES
65-66.
WY...NONE.
&&
$$
WEATHER.GOV/BILLINGS
AREA FORECAST DISCUSSION
NWS HASTINGS NE
1125 AM CST WED DEC 11 2013
.UPDATE...
ISSUED AT 647 AM CST WED DEC 11 2013
ONLY MADE SOME VERY MINOR TWEAKS FOR THE LATEST UPDATE. AFTER
BRINGING THE LATEST TEMPS/DEWPOINTS IN LINE WITH CURRENT
OBS AND PERUSING LATEST SETS OF MODEL DATA...OPTED TO MAKE A
VERY MINOR...ACROSS-THE-BOARD 1 DEGREE DROP IN HIGHS TODAY VERSUS
EARLIER FORECAST. IN OTHER WORDS...A TAD BIT MORE OF MAINLY THE
NORTHEAST CWA IS NOW AIMED TO FALL SHORT OF 20. ALSO BUMPED UP SKY
COVER INTO PARTLY CLOUDY TERRITORY FOR A TIME THIS MORNING IN FAR
SOUTHERN ZONES TO ACCOUNT FOR EAST-WEST-BAND OF CIRRUS THAT IS
CENTERED JUST SOUTH OF THE CWA. OTHERWISE...SMALL SPLOTCHES OF
LOW STRATUS CONTINUE TO DRIFT ACROSS LIMITED PARTS OF BOTH THE
WESTERN/EASTERN CWA...AND AS EVIDENCED BY THE OB AT HEBRON A
LITTLE WHILE AGO...SOME ROGUE/BRIEF FLURRIES CANNOT BE RULED OUT
WHEREVER THESE CLOUDS HAPPEN TO BE. AS DETAILED IN THE EARLIER
DISCUSSION...DAY SHIFT WILL HAVE TO KEEP AN EYE ON STRATUS TRENDS
OVER WESTERN NEB...JUST IN CASE SOME OF THIS STARTS TO EXPAND BACK
EASTWARD INTO THE WESTERN/NORTHWEST CWA LATER TODAY AS HINTED BY
THE LATEST RAP13 900MB RELATIVE HUMIDITY FORECAST. THIS IS NO SURE
THING THOUGH...AS THE LATEST HRRR KEEPS SKIES CLEAR PER ITS LOW
LEVEL CLOUD COVER PRODUCT.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 458 AM CST WED DEC 11 2013
IN THE MIDST OF THE MODEST TEMPERATURE-ROLLER COASTER WE ARE NOW
RIDING...TODAY STILL LOOKS LIKE THE OVERALL-COLDEST DAY OUT OF THE
NEXT 7...AS WE CATCH THE WESTERN EDGES OF A GLANCING BLOW OF
ARCTIC AIR THAT IS PRIMARILY PASSING NORTHEAST OF THE AREA. GIVEN
THAT THERE IS ESSENTIALLY ZERO RISK OF PRECIP DURING THE NEXT 24
HOURS...TEMPS CONTINUE TO BE THE MAIN ISSUE...AND AGAIN WOULD
CONSIDER THIS TO BE AN ABOVE-AVERAGE CHALLENGE GIVEN FACTORS SUCH
AS MODEL DISAGREEMENT ON THE MAGNITUDE OF THE COLD AIR TODAY...AND
HOW MUCH OF A NON-DIURNAL TREND TONIGHT COULD HAVE OWING TO STEADY
SOUTHWEST BREEZES.
STARTING OFF EARLY THIS MORNING...THE VAST MAJORITY OF THE CWA IS
SITTING UNDER CLEAR/MOSTLY CLEAR SKIES IN THE WAKE OF A QUICK-
HITTING SYSTEM THAT BROUGHT A ROUND OF FLURRIES/BRIEF VERY LIGHT
SNOW TO MAINLY THE NORTHEAST 1/2 OF THE AREA EARLIER IN THE NIGHT.
THE ONLY REAL EXCEPTION TO THE CLEAR SKIES ARE FAIRLY RANDOM
PATCHES OF LOW STRATUS BASED AROUND 2000 FT THAT ARE DRIFTING
SOUTHWARD ACROSS THE AREA...ALTHOUGH 11-3.9 MICRON SATELLITE HAS
SUGGESTED THAT THIS STRATUS IS DIMINISHING IN AREAL COVERAGE. IN
THE BIG PICTURE ALOFT...WATER VAPOR SATELLITE AND SHORT TERM MODEL
DATA CONTINUE TO DEPICT...A BROAD LONGWAVE TROUGH ENCOMPASSING
MUCH OF THE CONUS...ALTHOUGH NOW A HIGH-AMPLITUDE RIDGE IS SET UP
JUST ALONG/OFF THE PACIFIC COAST...WHILE A NEARLY CUT OFF LOW
SPINS OFF NORTHERN BAJA. CLOSER TO HOME...THE LATEST IN A SERIES
OF NORTHWEST OF NORTHWEST-FLOW/CLIPPER SHORTWAVES IS STILL IN THE
PROCESS OF SHIFTING EASTWARD ACROSS EASTERN NEB/EASTERN
DAKOTAS/IA/MN...WHILE THE ENTIRE CENTRAL PLAINS GENERALLY RESIDES
IN THE ENTRANCE REGION OF A 130+KT UPPER JET STREAK EVIDENT AT
300MB AND CENTERED FROM EASTERN IA EASTWARD. AT THE SURFACE...09Z
OBJECTIVE SURFACE ANALYSIS HIGHLIGHTS A COLD/DRY 1036MB RIDGE AXIS
CENTERED OVER SOUTHEAST SD. SOUTH OF THE HIGH CENTER...AT-TIMES BREEZY
NORTHERLY WINDS QUICKLY OVERTOOK THE ENTIRE CWA THROUGH THE
NIGHT IN THE WAKE OF THE FAIRLY STRONG COLD FRONT...WITH SUSTAINED
SPEEDS CURRENTLY AVERAGING AT LEAST 10-15 MPH WITH SOME GUSTS TO
AROUND 20 OR HIGHER. FAIRLY PRONOUNCED COLD AIR ADVECTION IS
ESTABLISHED ACROSS THE REGION...WITH 10Z TEMPS LOCALLY RANGING
FROM 8 AT ORD...TO 16 AT HASTINGS...TO 23 AT BELOIT. AT THE
CURRENT RATE...ACTUAL MORNING LOWS BY 14Z/8AM ARE ON TRACK TO
RANGE FROM AROUND 2 IN THE FAR NORTHERN CWA...TO 14-16 IN THE FAR
SOUTH.
TURNING TO THE FORECAST AND STARTING WITH THE PRE-DAWN HOURS...THE
IMMEDIATE SHORT TERM ISSUE IS NAILING DOWN THE STEADY
TEMPERATURE/DEWPOINT DROPS. THANKS TO THE FALLING TEMPS AND STEADY
NORTH WINDS...WIND CHILLS BY SUNRISE ARE PROGGED TO BE WELL INTO
THE ZERO TO -10 RANGE ACROSS ROUGHLY THE NORTHEAST HALF OF THE
CWA...WITH THE FAR NORTHEAST POSSIBLE EVEN PUSHING -15.
OTHERWISE...ALTHOUGH NOT IN THE OFFICIAL FORECAST DUE TO ITS
EXTREMELY LIMITED COVERAGE...ANY OF THE REMAINING PATCHES OF LOW
STRATUS THIS MORNING COULD SQUEEZE OUT A ROGUE...BRIEF
FLURRY...SUCH AS RECENTLY REPORTED BY AWOS SITES SUCH AS
YORK/ALBION.
FOR THE DAYTIME HOURS...THE SYNOPTIC-SCALE ALOFT WILL FEATURE THE
CONTINUED DEPARTURE OF THE AFOREMENTIONED SHORTWAVE
TROUGH...ALLOWING THE WESTERN CONUS RIDGE TO START EASING EASTWARD
INTO THE CENTRAL PLAINS...RESULTING IN SUBTLE MID LEVEL HEIGHT
RISES. AT THE SURFACE...THE STOUT RIDGE CURRENTLY CENTERED OVER SD
WILL GRADUALLY SLIDE SOUTHEAST TO AN AXIS FROM SOUTHEAST KS-
SOUTHEAST IA BY SUNSET. AS THIS FEATURE PASSES ACROSS THE
CWA...THE MORNING WILL START OUT WITH NORTHERLY BREEZES AROUND 10
MPH IN THE EAST WHILE THE WEST STARTS TO GO LIGHT/VARIABLE. AS THE
DAY GOES ON...THE FAIRLY NARROW CORRIDOR OF LIGHT/VARIABLE BREEZES
WILL SLIDE EASTWARD ACROSS THE AREA...ALLOWING SOUTHWESTERLY FLOW
TO TAKE OVER IN ITS WAKE. BY LATE AFTERNOON...SUSTAINED 5-15 MPH
SOUTHWEST BREEZES WILL BE IN PLACE...LIGHTEST IN THE SOUTHEAST AND
STRONGEST NORTHWEST. AS FOR CLOUD COVER TODAY...EXPECT
SUNNY/MOSTLY SUNNY SKIES TO DOMINATE THE MAJORITY OF THE
AREA...AND THIS IS REFLECTED IN THE FORECAST GRIDS. HOWEVER...ONE
POTENTIAL CAVEAT TO WATCH FOR IS THE EVOLUTION OF LOW STRATUS OVER
WESTERN NEB...AS MODELS SUCH AS THE RAP13 SUGGEST THAT SOME OF
THIS STRATUS COULD GET CAUGHT IN THE SOUTHWEST LOW-LEVEL FLOW ON
THE BACKSIDE OF THE RIDGE AND TRY TO PUSH EASTWARD INTO AT LEAST
THE FAR WESTERN CWA THIS AFTERNOON. HOWEVER...ODDS ARE BETTER THAT
THE MAJORITY OF THIS POTENTIAL LOW CLOUD MASS WOULD FOCUS JUST
OUTSIDE THE CWA TO THE WEST/NORTHWEST. AT ANY RATE...RUNNING WITH
THE NO-WORSE-THAN MOSTLY SUNNY ASSUMPTION...THE BIG QUESTION
TODAY CENTERS AROUND THE BATTLE BETWEEN SUN AND DEVELOPING
SOUTHWESTERLY BREEZES...WHICH FAVORS WARMING...AND THE VERY COLD
LOW LEVEL AIRMASS THAT THE AREA IS STARTING THE DAY WITH ALONG
WITH LINGERING SNOW COVER...WHICH FAVORS COLDER. AFTER
PERUSING/BLENDING VARIOUS MODEL 2M TEMPS/GUIDANCE
SOLUTIONS...OPTED TO ONLY MAKE MINOR TWEAKS TO PREVIOUS
FORECAST...AIMING FOR A RANGE IN HIGHS FROM 16-20 ACROSS ROUGHLY
THE NORTHEAST 1/2...AND 22-26 ACROSS MUCH OF THE SOUTHWEST HALF.
ADMITTEDLY...THIS HAS THE POTENTIAL TO BE AN OPTIMISTIC
FORECAST...AS SOME DATA SETS SUCH AS THE 06Z NAM AND THE 00Z MAV
SUGGEST THAT GOING HIGHS ARE ROUGHLY 5 DEGREES TOO WARM. THE
FEELING AT THIS TIME IS THAT THESE SOLUTIONS ARE JUST A BIT TOO
PESSIMISTIC THOUGH...ESPECIALLY OVER THE RATHER SNOW-FREE
WESTERN/SOUTHERN ZONES.
TURNING TO THIS EVENING/TONIGHT...THE MAIN HIGHLIGHT WILL BE
MODEST BUT STEADY LOW-LEVEL WARM AIR ADVECTION...AS 850MB TEMPS
OVER THE CWA ARE PROGGED TO CLIMB FROM BETWEEN -3 TO -7C AT
00Z/6PM TO BETWEEN ZERO AND +4C BY 12Z/6AM. THE QUESTION THOUGH IS
HOW MUCH OF THIS WARMING WILL TRULY BE REALIZED AT THE SURFACE. ON
THE LARGE SCALE ALOFT TONIGHT...STEADY MID LEVEL HEIGHT RISES WILL
CONTINUE...AS THE BROAD WESTERN CONUS RIDGE EXERTS INCREASING
INFLUENCE...FURTHER DISPLACING THE LOCAL AREA FROM STRONGER UPPER
FLOW ASSOCIATED WITH SPLIT JET STREAMS...ONE ARCING ACROSS THE
U.S/CANADA BORDER INTO THE GREAT LAKES...AND THE SOUTHERN ONE
CENTERED FROM BAJA ACROSS TX INTO THE SOUTHEAST STATES. AT THE
SURFACE...BROAD SOUTHWESTERLY FLOW WILL PERSIST ACROSS THE CENTRAL
PLAINS TO THE NORTHWEST OF THE SOUTHEAST-MOVING RIDGE AXIS...WITH
SUSTAINED SPEEDS LOCALLY RANGING FROM 8-14 MPH WITH SOME HIGHER
GUSTS THROUGH MOST OF THE NIGHT...UNTIL A LULL TO MORE SO 5-8 MPH
OCCURS VERY LATE TOWARD SUNRISE THURSDAY. THIS SORT OF OVERNIGHT
PATTERN WITH STEADY SOUTHWEST BREEZES STRONGLY ARGUES FOR NEAR-
STEADY IF NOT SLOWLY RISING TEMPS IN SOME AREAS...BUT OTHER
FACTORS SUCH AS EXPECTED CLEAR/MOSTLY CLEAR SKIES...SNOW COVER AND
THE MODEST DECREASE IN WIND SPEEDS LATE IN THE NIGHT SUGGESTS THAT
THERE WILL LIKELY BE A COMPLEX BEHAVIOR OF HOURLY TEMPS
TONIGHT...SOMEWHAT AS WHAT OCCURRED MONDAY NIGHT/EARLY TUESDAY
MORNING. IN THE END...OPTED TO LEAN ACTUAL LOWS TOWARD THE MIDDLE
GROUND OF A RATHER WIDE-RANGE OF MODEL/GUIDANCE SOLUTIONS...BUT
THIS STILL ENDED UP RESULTING IN AN UPWARD NUDGE OF 3-4 DEGREES
FROM PREVIOUS FORECAST...CALLING FOR A FAIRLY UNIFORM RANGE ACROSS
THE CWA OF 9-12 DEGREES. THESE VALUES ARE A SOLID 3-5 DEGREES
ABOVE A 00Z MET/MAV GUIDANCE BLEND...WHICH JUST LOOKS TOO COLD
GIVEN THE WESTERLY FLOW/WARM AIR ADVECTION. BY THE SAME
TOKEN...THE OFFICIAL FORECAST IS NOT AS WARM AS RAW 2M TEMPS FROM
MODELS SUCH AS THE GFS/ECMWF...WHICH SUGGEST MUCH OF THE
WEST/SOUTH COULD HOLD ABOVE 15 THROUGH THE NIGHT.
.LONG TERM...(THURSDAY THROUGH TUESDAY)
ISSUED AT 458 AM CST WED DEC 11 2013
THE PRIMARY CHALLENGE WILL CONTINUE TO BE THE TEMPERATURE FORECAST
AND HOW TO HANDLE THE SNOW COVER IMPACTS ON TEMPERATURES. WE ARE IN
FOR A VERY NICE WARM-UP ON THURSDAY...LIKELY THE WARMEST DAY IN OVER
A WEEK. EXPECT A COLD FRONTAL PASSAGE ON FRIDAY THAT WILL RESULT IN
A RETURN OF SUB-FREEZING TEMPERATURES FOR MOST AREAS. SUNDAY SHOULD
BE A TRANSITION DAY WITH WARMER WESTERLY WINDS FOLLOWED BY EVEN
WARMER TEMPERATURES EARLY NEXT WEEK WHEN HIGHS SHOULD GENERALLY BE
ABOVE FREEZING. AT THIS TIME WE ARE NOT EXPECTING ANY ADDITIONAL
ACCUMULATING SNOWFALL EVENTS DURING THE LONG TERM PERIOD BUT CAN NOT
COMPLETELY RULE OUT FLURRIES.
THURSDAY...THE SFC WIND WILL TURN SOUTHWESTERLY AS THE SFC HIGH
SLIDES EAST AND AN UPPER RIDGE WILL BUILD ACROSS THE WESTERN CONUS
SENDING WARMER AIR ALOFT INTO THE HIGH PLAINS. 850 MB TEMPERATURES
WILL RISE BY AROUND 10 TO 15C FROM WEDNESDAY AFTERNOON TO THURSDAY
AFTERNOON. THEREFORE...EXPECT A QUICK WARM-UP WITH THE SNOW COVER
BEING THE ONLY THING LEFT LIMITING THE RISE. THERE CERTAINLY COULD
BE A 10 DEGREE OR GREATER DIFFERENCE IN HIGH TEMPERATURES BETWEEN
LOCATIONS WITH SNOW AND THOSE WITHOUT SNOW. FOR INSTANCE...WILL CALL
FOR A HIGH OF 42 IN ORD...AND UPPER 40S IN SOUTHERN TIER OF KS
COUNTIES WHERE THERE IS NO SNOW...BUT WILL ONLY CALL FOR A HIGH OF
32 IN HASTINGS DUE TO SNOW COVER.
FRIDAY...UNCERTAINTY IN TEMPERATURE FORECAST IS RATHER HIGH AS A
COLD FRONT WILL TRACK THROUGH DURING THE DAY AND THE MAGNITUDE OF
THE COLD AIR VARIES FROM MODEL TO MODEL. THE NAM RAW TEMPERATURES
ARE TOO COLD WITH THE NAM BELIEVING THERE IS A DEEPER AND MORE
WIDESPREAD SNOW PACK THAN WE REALLY HAVE. THE 00Z ECMWF MAY BE A
LITTLE TOO WARM AND HAVE LEANED TOWARD THE MIDDLE GROUND 00Z GFS. WE
SHOULD GENERALLY BE LOOKING AT UPPER 20S TO LOWER 30S ACROSS MOST OF
THE FORECAST AREA. DID NOT ACCOUNT FOR A SNOW COVER DIFFERENCE IN
THE TEMPERATURE FIELD DUE TO UNCERTAINTY WITH REGARD TO HOW MUCH
SNOW COVER WILL REMAIN AFTER THURSDAY. WITH REGARD TO
PRECIPITATION...IT SHOULD BE DRY...BUT IT MAY BE A CLOSE CALL FOR
SOUTHEASTERN ZONES AS A SHORTWAVE TRACKS ACROSS THE SOUTHERN PLAINS
AND SPREADS LIGHT SNOW AS FAR NORTH AS SOUTH CENTRAL KANSAS INTO
NORTHEAST KANSAS.
SATURDAY...FORECAST MODELS ARE FAIRLY CONSISTENT IN SHOWING A COOL
HIGH PRESSURE OVERHEAD WITH LIGHT NORTHERLY FLOW BEHIND A DEPARTING
UPPER LEVEL WAVE. NORTHEAST ZONES WILL CERTAINLY GET THE FULLER
BLAST OF THE COLD AND WILL STRUGGLE INTO THE MID 20S WHILE OUR
SOUTHWESTERN ZONES FROM BEAVER CITY TO STOCKTON MAY FLIRT WITH HIGHS
NEAR THE FREEZING MARK. SUBSIDENCE AND DRY WEATHER IS EXPECTED.
SUNDAY THROUGH TUESDAY...UNCERTAINTY REMAINS HIGH BUT HAS IMPROVED
SOME WITH MODELS TRENDING CLOSER TOGETHER AND MORE IN LINE WITH A
WARMER WEATHER REGIME. USED THE ALLBLEND MODEL SOLUTION FOR THESE
OUTER PERIODS...WHICH MAY BE A BIT TOO COOL IF CURRENT WARMER MODEL
TRENDS CONTINUE AND PREVAIL. THE OVERALL PATTERN THESE DAYS WILL BE
AN UPPER RIDGE OVER THE WESTERN CONUS AND THE JET STREAM GENERALLY
NORTH OF OUR FORECAST AREA. EXPECT TEMPERATURES WILL BE WARMER
SUNDAY THAN ON SATURDAY AND THEN EVEN WARMER STILL BY MONDAY AND
TUESDAY. ANY REMAINING SNOW WILL LIKELY MELT UNDER THIS SET UP.
THERE IS STILL HOPE FOR THOSE WANTING A WHITE CHRISTMAS AS BOTH THE
00Z GFS AND 00Z ECWMF SHOW A SHARP TURN TOWARDS COLD BY DEC 20TH OR
21ST WITH THE POTENTIAL OF A WINTER STORM SYSTEM SOMEWHERE IN THE
PLAINS JUST BEFORE CHRISTMAS BUT WAY TO EARLY TO PIN POINT ANYTHING.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z THURSDAY AFTERNOON)
ISSUED AT 1118 AM CST WED DEC 11 2013
LIGHT AND VARIABLE WINDS UNDER INFLUENCE OF SFC RIDGE AXIS WILL
TRANSITION SOUTHWESTERLY AS THE RIDGE SLIDES SOUTHEAST INTO
MISSOURI TODAY. PATCHY LOW CLOUDS RESIDE WEST AND SOUTH OF THE
TERMINAL AND EXPECT THE CLOUDS TO DIMINISH DURING THE DAY WITH NO
EFFECT FOR KGRI. HEADING INTO THIS EVENING AND THE FIRST PART OF
THE NIGHT HAVE MAINTAINED POTENTIAL FOR LOW LEVEL WIND SHEAR AS
LLVL WINDS RAPIDLY INCREASE WITH HEIGHT TO AROUND 40KTS.
&&
.GID WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
KS...NONE.
&&
$$
UPDATE...PFANNKUCH
SHORT TERM...PFANNKUCH
LONG TERM...WESELY
AVIATION...FAY
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
1141 AM CST WED DEC 11 2013
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 334 AM CST WED DEC 11 2013
MAIN FORECAST CONCERNS ARE ON WIND CHILLS THROUGH TONIGHT AND
PRECIPITATION CHANCES TONIGHT.
CURRENTLY AS OF 09Z...WATER VAPOR LOOP AND RAP 500MB HEIGHT ANALYSIS
SHOWED UPPER RIDGING NEAR THE WEST COAST OF THE U.S....BROAD
TROUGHING OVER THE EAST HALF OF CANADA...AND A SHORTWAVE TROUGH
STRETCHING FROM MN INTO NEBRASKA. AHEAD OF THIS SHORTWAVE TROUGH...A
FRONTOGENESIS BAND OF SNOW ENCOMPASSED MUCH OF EASTERN IOWA INTO
SOUTHERN WI...WHILE CLOUDS COVERED MUCH OF THE FORECAST AREA.
HOWEVER...CLEARING ASSOCIATED WITH SUBSIDENCE IN THE TROUGH WAS
QUICKLY APPROACHING THE FORECAST AREA FROM CENTRAL MN. THIS CLEARING
WAS RIGHT BEHIND A COLD FRONT...WHICH ALSO REPRESENTS AN ARCTIC
AIRMASS POISED TO COME INTO THE AREA TODAY. READINGS ARE BELOW ZERO
FROM NORTH DAKOTA INTO CENTRAL MN...AND IN MANY SPOTS TEENS BELOW
ZERO. 850MB STANDARDIZED TEMPERATURE ANOMALIES ASSOCIATED WITH THIS
ARCTIC AIRMASS ARE 2 BELOW NORMAL. ACCOMPANYING THE ARCTIC AIR ARE
SOME BRISK NORTHWEST WINDS...PARTICULARLY WITH THE ISALLOBARIC PUSH
RIGHT BEHIND THE COLD FRONT. THESE WINDS ARE KNOCKING WIND CHILLS
DOWN TO 20 TO 35 BELOW FROM CENTRAL MN THROUGH NORTHERN WI
NORTHWESTWARD.
THE COLD AIR AND CLEARING SEEN OVER CENTRAL MN WILL RUSH INTO THE
FORECAST AREA QUICKLY THIS MORNING...ASSOCIATED WITH THE COLD
FRONTAL AND SHORTWAVE TROUGH PASSAGE. WINDS SHOULD STAY BRISK ALL
DAY AS A SURFACE OVER THE WESTERN DAKOTAS ENDS UP SLIDING WELL TO
OUR SOUTH...INTO NORTHERN MO BY 00Z. THE STRONGEST WINDS ARE LIKELY
THIS MORNING AS PRESSURES RISE RAPIDLY. TEMPERATURES LOOK TO FALL
THROUGH MID MORNING...MAY GET A LITTLE BUMP UP EARLY THIS AFTERNOON
WITH DAYTIME HEATING...AND FALL YET AGAIN ONCE THE SUN STARTS GOING
DOWN. THUS...ITS GOING TO BE TOUGH TO WARM TODAY. HIGHS IN THE
SINGLE DIGITS ABOVE ZERO APPEARS TO BE ALL WE CAN GET...WITH
LOCATIONS NORTH OF HIGHWAY 10 NOT EVEN REACHING ZERO. FACTOR IN THE
WIND AND MUCH OF THE AREA WILL SEE WIND CHILLS REACHING 20 BELOW
ZERO OR COLDER AT TIMES...ESPECIALLY THIS MORNING AND LATE TODAY.
REGARDING HAZARDS...LIKELY SOMETIME BETWEEN 12-13Z TODAY WE CAN
TRANSITION THE WINTER WEATHER ADVISORY OVER TO A WIND CHILL
ADVISORY IN NORTHEAST IOWA.
THIS SHOT OF ARCTIC AIR APPEARS TO BE SHORT-LIVED...HOWEVER. A
SHORTWAVE SEEN OVER ALBERTA IS PROGGED BY MODELS TO DROP DOWN
THROUGH CENTRAL MN AND WI BETWEEN 06-12Z TONIGHT. THE APPROACH OF
THE SHORTWAVE HELPS TO SWING WINDS AROUND TO THE SOUTHWEST...AND
SPREAD SOME MID/HIGH CLOUDS INTO THE AREA RESULTING FROM DPVA AND
ISENTROPIC LIFT. SO AFTER SOME COOLING FROM RADIATIONAL PROCESSES IN
THE EVENING...ADVECTIVE PROCESSES WILL HELP TEMPERATURES CLIMB
THEREAFTER. GIVEN THE COLD EVENING...EXTENDED THE WIND CHILL
ADVISORY THROUGH 12Z THU FOR SOUTHEAST MN INTO SOUTHWEST AND
CENTRAL WI. EXPANDED BOTH IN TIME AND AREA THE ADVISORY TO HELP
BLEND WITH MKX AND DVN OFFICES. THE NEXT QUESTION IS IF ANY SNOW
CAN FALL WITH THE SHORTWAVE. THE 11.00Z GFS/CANADIAN/ECMWF ALL
PRODUCE A BAND OF LIGHT QPF...WITH SOUNDINGS SUGGESTING THE
FORCING IS MOSTLY CO- LOCATED WITH THE DENDRITIC GROWTH ZONE. THE
AFOREMENTIONED MODELS ALL SUGGEST A QUICK MOVING BAND...LIMITING
ACCUMULATIONS...BUT A FEW TENTHS SEEM REASONABLE. HAVE RAISED
PRECIPITATION CHANCES TOWARDS 60. NAM IS THE ONLY MODEL NOT
SHOWING ANY PRECIPITATION...BUT EVEN IT HAS INDICATIONS OF THE
FORCING.
.LONG TERM...(THURSDAY THROUGH TUESDAY)
ISSUED AT 334 AM CST WED DEC 11 2013
MAIN LONG TERM FORECAST CONCERNS ARE ON MINIMAL PRECIPITATION
CHANCES THROUGHOUT.
SOME DEAMPLIFICATION OF THE FLOW ACROSS THE NORTHERN U.S. IS PROGGED
TO OCCUR THURSDAY THROUGH FRIDAY IN RESPONSE TO A TROUGH DROPPING
DOWN THROUGH THE PACIFIC NORTHWEST. THE SWITCH TO A ZONAL FLOW
PATTERN IN THE NORTHERN STREAM APPEARS TO HAVE PLENTY OF MID/UPPER
LEVEL MOISTURE...WHICH IS GOING TO MANIFEST ITSELF IN A LOT OF
CLOUDS. PRECIPITATION CHANCES OVERALL LOOK PRETTY MINIMAL...
THOUGH...AS PLENTIFUL DRY LOW LEVEL AIR IS IN PLACE. ADDITIONALLY...
FORCING APPEARS RESTRICTED TO SOME WEAK MID LEVEL FRONTOGENESIS
STRETCHING FROM NORTHERN/CENTRAL MN INTO NORTHERN WI THU NIGHT AND
FRIDAY. THIS FORCING COULD SQUEEZE OUT SOME SNOW...BUT CONFIDENCE IS
ONLY HIGH ENOUGH FOR A 20 PERCENT CHANCE NORTH OF HIGHWAY 10.
REGARDING THAT AFOREMENTIONED FRONTOGENESIS...THIS WILL OCCUR BEHIND
A COLD FRONTAL PASSAGE PROGGED TO MOVE THROUGH THE AREA THU NIGHT.
SO AFTER A WARMER THURSDAY IN RESPONSE TO LOW LEVEL WARM
ADVECTION...TEMPERATURES HEAD BACK DOWN THU NIGHT...BUT NOT NEARLY
AS COLD AS IT HAS BEEN. DESPITE THE COLD ADVECTION...TEMPERATURES
FRIDAY SHOULD REBOUND CLOSE TO THURSDAYS HIGHS.
FOR FRIDAY NIGHT AND SATURDAY...THE FOCUS HAS BEEN ON A SHORTWAVE
TROUGH AND GENERAL SYSTEM COMING OUT OF THE CENTRAL PLAINS. THIS
SHORTWAVE TROUGH IS CURRENTLY AN UPPER LOW SITTING OFF THE FAR
SOUTHERN CALIFORNIA COAST. 11.00Z ECMWF/GFS/CANADIAN HAVE TRENDED
SLIGHTLY FARTHER SOUTHEAST WITH THIS SYSTEM...AND AS SUCH...THE
PRECIPITATION ALSO MOVED A LITTLE FARTHER AWAY. THERE STILL ARE
INDICATIONS THAT THE MID LEVEL FRONTOGENESIS SITTING OVER NORTHERN
WI ON FRIDAY WILL SLIDE SOUTH OVER THE REST OF THE AREA FRIDAY
NIGHT...POSSIBLY SQUEEZING OUT A LITTLE LIGHT SNOW.
THEREFORE...HAVE HAD TO MAINTAIN SOME 20-40 PERCENT
CHANCES...HIGHEST BETWEEN 06-12Z SATURDAY. CHANCES CONTINUE
THROUGH THE DAY SATURDAY AND INTO SATURDAY NIGHT...MORE IN
RESPONSE TO A POTENT SHORTWAVE TROUGH DROPPING DOWN FROM MANITOBA
INTO UPPER MICHIGAN.
FOR SUNDAY AND BEYOND...SUNDAY IS LOOKING CHILLY AS THE POTENT
TROUGH BRINGS DOWN A BRIEF SHOT OF ARCTIC AIR WITH IT ON ITS BACK
SIDE. 850MB TEMPS FALL TO -14 TO -20C AT 18Z SUNDAY PER 11.00Z
ECMWF...COLDEST OVER TAYLOR COUNTY. MAY GET CLOSE FOR NEEDING A WIND
CHILL ADVISORY SUNDAY MORNING. A WARM ADVECTION PATTERN THEN LOOKS
TO ENSUE FOR SUNDAY NIGHT INTO MONDAY AS YET ANOTHER DECENT
SHORTWAVE TROUGH TRACKS FROM MANITOBA INTO UPPER MICHIGAN. FOLLOWED
CONSENSUS AND INCLUDED 20 PERCENT CHANCES FOR MONDAY. TEMPERATURES
MAY REBOUND HIGHER TOO THAN CURRENTLY FORECAST...BUT GIVEN HOW FAR
OUT THIS PERIOD IS IN THE FORECAST...STAYED CLOSER TO A MODEL
CONSENSUS WITH HIGHS IN THE 15-20 RANGE.
FOR THOSE LOOKING FOR A WARM-UP...THE ECMWF CONTINUES TO HINT AT ONE
FOR THE MIDDLE TO END OF NEXT WEEK AS A DEEP TROUGH FORMS OVER THE
WESTERN U.S.. THE CFS HAS ALSO BEEN ADVERTISING ABOVE NORMAL
TEMPERATURES DURING THIS SAME TIME PERIOD.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z THURSDAY AFTERNOON)
ISSUED AT 1141 AM CST WED DEC 11 2013
COLD CYLCONIC NORTHWEST FLOW ALOFT WILL USHER IN ANOTHER WEAK
SHORTWAVE TROUGH INTO THE REGION THIS EVENING/OVERNIGHT. PLAN ON
VFR CONDITIONS TO DETERIORATE INTO MVFR RANGE AS THIS WAVE
APPROACHES IN THE 06-08Z TIME FRAME AS CLOUD HEIGHTS LOWER AND
VISIBILITY GETS REDUCED IN FALLING LIGHT SNOW. EXPECTING KLSE TO
BE IMPACTED BY THE FALLING SNOW MORE THAN KRST. NOT EXPECTING MORE
THAN 1/4-1/2 INCH. IT APPEARS THE LIGHT SNOW WILL EXIT EAST OF
THE AREA SOON AFTER DAYBREAK WITH LINGERING MVFR/IFR STRATUS
THROUGH THE REST OF THE MORNING HOURS.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
WI...WIND CHILL ADVISORY UNTIL 6 AM CST THURSDAY FOR WIZ017-029-
032>034-041>044.
WIND CHILL ADVISORY FROM 6 PM THIS EVENING TO 6 AM CST THURSDAY
FOR WIZ053>055-061.
MN...WIND CHILL ADVISORY UNTIL 6 AM CST THURSDAY FOR MNZ079-086>088-
094>096.
IA...WIND CHILL ADVISORY UNTIL 6 AM CST THURSDAY FOR IAZ008>010-018-
019-029.
WIND CHILL ADVISORY FROM 6 PM THIS EVENING TO 6 AM CST THURSDAY
FOR IAZ011-030.
&&
$$
SHORT TERM...AJ
LONG TERM...AJ
AVIATION...DAS