Forecast Discussions mentioning any of
"HRRR" "RAP" "RR" "RUC13" "RUC" received at GSD on 01/17/13
AREA FORECAST DISCUSSION
NWS DENVER/BOULDER CO
1007 AM MST TUE JAN 15 2013
.UPDATE...
&&
.SHORT TERM...OVERALL...CURRENT FORECAST LOOK ON TRACK. ELONGATED
UPPER TROUGH CURRENTLY ACROSS FAR EASTERN COLORADO WITH NORTHERLY
FLOW ALOFT OVER COLORADO. MOISTURE HAS BEEN STREAMING INTO THE
STATE FROM THE NORTH AND NORTHWEST...THOUGH NOT MUCH IN THE WAY OF
ANY SNOWFALL SHOWING UP ON THE MOUNTAIN WEB CAMS. ENOUGH
OROGRAPHICS TO KEEP THE CURRENT CHANCE POPS FOR MOUNTAINS. HOWEVER
THE WARM AIR ADVECTION AND LACK OF MID LEVEL QG SUPPORT SHOULD KEEP
SNOW AMOUNTS LIMITED. WILL MAINTAIN THE 1-2 INCH RANGE...THOUGH
THE LOCAL 4 INCH SPOTS MAY BE OVERDONE. STILL A SLIGHT CHANCE FOR
SOME LIGHT SNOW THIS EVENING AWAY FROM THE LOCAL DOWNSLOPE OF THE
FOOTHILLS IN FAR NORTHEAST CORNER AND ALONG THE PALMER. ACCUMULATIONS
THERE TO BE MINIMAL. PERHAPS SOME VIRGA ELSEWHERE ACROSS THE
PLAINS. EXPECTED WARMUP TO BE SLOW TO OCCUR TODAY DUE TO
PERSISTANT INVERSIONS IN MOUNTAIN VALLEYS AND LOW LYING AREAS OF
THE PLAINS AS WELL AS THE INCREASING MID LEVEL CLOUD DECK. CURRENT
TEMPERATURE GRIDS SEEM REASONABLE AT THIS TIME...MAY NEED TO
ADJUST A BIT BASED ON CURRENT TRENDS.
.AVIATION...LATEST RAP INDICATING WINDS BECOMING NORTHWEST AROUND
21Z...MORE IN LINE WITH GFS. NAM STILL SHOWING SOUTHWEST TO WEST
WINDS THOUGH LIGHTER THAN EARLIER RUNS. WILL INCLUDE SOME SORT OF
A NORTHWEST WIND FOR THE AREA AIRPORTS AROUND 21Z...WITH SPEEDS
AROUND 10 KTS. WINDS SHOULD SWITCH BACK TO SOUTHERLY THIS EVENING. REST
OF THE TAF TRENDS LOOK IN ORDER. STILL POTENTIAL FOR CEILINGS
AROUND 5000 FEET AGL BETWEEN 01Z AND 09Z WITH ILS CONDITIONS
DEVELOPING...BUT ANY SNOW THAT DEVELOPS SHOULD REMAIN SOUTH AND
EAST OF THE DENVER AREA.
&&
.PREV DISCUSSION... /ISSUED 258 AM MST TUE JAN 15 2013/
SHORT TERM...AFTER A VERY COLD START...THE LONG ANTICIPATED
WARMUP WILL FINALLY BEGIN TODAY. STRONG WARM ADVECTION ALOFT
OCCURS LATER THIS MORNING THROUGH TONIGHT. HOWEVER...THE WARMUP
WILL BE TEMPERED CONSIDERABLY BY THE VERY COLD START AND MID LEVEL
WARM ADVECTION CLOUD DECK WHICH WILL OVERSPREAD THE FORECAST AREA
THIS MORNING. VALLEY LOCATIONS WILL STRUGGLE THE MOST TO WARM
UP...BUT LOCATIONS IN/NEAR THE FOOTHILLS WITH SOME DOWNSLOPE
COMPONENT WILL LIKELY SEE UPPER 20S AND 30S TODAY. THERE IS ENOUGH
MOISTURE AND OROGRAPHICS TO PRODUCE SNOW IN THE MOUNTAINS ALTHOUGH
IT WILL BE LIGHT WITH THE STABILIZING EFFECTS OF WARM ADVECTION.
ACCUMULATIONS SHOULD MAINLY RANGE FROM 1-2 INCHES OVER THE
MOUNTAINS WITH PERHAPS AS MUCH AS 4 INCHES IN A COUPLE SPOTS FROM
ROCKY MOUNTAIN NATIONAL PARK TOWARD THE WYOMING BORDER WHERE
MOISTURE IS MORE PLENTIFUL. HIGHEST CHANCE OF SNOW WILL BE FROM
LATE AFTERNOON THROUGH THIS EVENING. ON THE PLAINS...THE WARM
ADVECTION APPEARS TO BE STRONG ENOUGH TO PRODUCE A CONSIDERABLE
MID LEVEL CLOUD DECK AND MAINLY VIRGA. HOWEVER...THE DOWNSLOPE
COMPONENT WILL BE WEAKEST OVER THE NORTHEAST PLAINS AND PALMER
DIVIDE WITH DEEPER NORTH/NORTHWEST FLOW...SO WILL HAVE A CHANCE OF
LIGHT SNOW THERE TONIGHT. OVERNIGHT LOWS WILL BE CONSIDERABLY
WARMER WITH CONTINUED WARM ADVECTION AND CLOUDS THROUGH MOST OF
THE NIGHT.
INCREASING NORTHWEST WINDS WILL OCCUR AS FLOW ALOFT STRENGTHENS
TODAY. THIS WILL CREATE A PERIOD OF NEAR WIND CHILL WARNING
CRITERIA IN THE MOUNTAINS AND FOOTHILLS THIS MORNING.
HOWEVER...TEMPS ARE BEGINNING TO WARM AS WINDS INCREASE SO WILL
HIGHLIGHT THIS IN THE SHORT TERM FORECAST FOR NOW. ON THE
PLAINS...TEMPERATURES WILL WARM SUFFICIENTLY AS WINDS INCREASE
LATER TODAY THROUGH TONIGHT SO NO HIGHLIGHTS NEEDED.
LONG TERM...STRONG UPPER LEVEL RIDGE WILL BE ALONG THE WEST COAST
AND A DEEP UPPER LEVEL LOW WILL BE CENTERED OVER THE HUDSON BAY TO
START THE EXTENDED PERIOD ON WEDNESDAY. THIS GENERAL PATTERN WILL
HOLD THROUGH THE WEEKEND AND INTO NEXT WEEK. FOR WEDNESDAY THROUGH
FRIDAY...A NORTHWEST FLOW ALOFT WILL BRING MILD AND DRY CONDITIONS
WITH TEMPERATURES CLIMBING ABOVE NORMAL ACROSS NORTHEAST COLORADO.
COULD SEE SOME CLOUDS EARLY WEDNESDAY...OTHERWISE EXPECT MOSTLY
CLEAR SKIES THROUGH FRIDAY. BECAUSE OF THE CLEAR SKIES AND LIGHT
WINDS THE MOUNTAINS VALLEYS WILL BE COLD WITH LOWS WELL BELOW ZERO
AND HIGHS IN THE SINGLE DIGITS AND TEENS.
FOR THIS WEEKEND AND EARLY NEXT WEEK...A SERIES OF WAVES EMBEDDED IN
THE NORTHWEST FLOW ALOFT WILL MOVE ACROSS THE NORTHERN PLAINS. THE
AIR BEHIND THESE SYSTEMS WILL BE COLD. APPEARS THE FORECAST AREA MAY
SEE A GLANCING BLOW OR TWO OF COLD BETWEEN SATURDAY AND TUESDAY.
MODELS DIFFER ON THE TIMING OF THE COLD AIR...SO WILL TREND
TEMPERATURES A LITTLE COOLER BUT KEEP THEM NEAR NORMAL. AS FAR AS
PRECIPITATION GOES...NOT MUCH HOPE FOR ANYTHING THROUGH AT LEAST
TUESDAY.
AVIATION...MID LEVEL CLOUD DECK WITH CEILINGS OF 6000-8000 FEET
WILL SPREAD ACROSS THE FRONT RANGE AIRPORTS 15Z-18Z. CLOUDS WILL
LIKELY LOWER A LITTLE FURTHER 18Z-22Z WITH ILS LANDING CONDITIONS
DEVELOPING AS CEILINGS OF 5000-6000 FEET BECOME MORE WIDESPREAD.
AT THIS TIME...EXPECT NOTHING MORE THAN VIRGA WITH ANY CHANCE OF
SNOW REACHING GROUND SOUTH AND EAST OF KDEN/KAPA.
SOUTHWEST WINDS SHOULD PREVAIL AT 10 KTS OR LESS TODAY AT KDEN
AND KAPA...AND THEN POSSIBLY INCREASE TO 12-15KTS OVERNIGHT. KBJC
SHOULD SEE A MORE WESTERLY COMPONENT DEVELOP BY 18Z-22Z WITH A FEW
GUSTS AROUND 20 KTS POSSIBLE.
&&
.BOU WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...D-L
LONG TERM....MEIER
AVIATION...D-L
AREA FORECAST DISCUSSION...CORRECTED
NWS NEW YORK NY
423 PM EST TUE JAN 15 2013
.SYNOPSIS...
LOW PRESSURE WILL RIDE ALONG THE STALLED FRONT TONIGHT INTO
WEDNESDAY...BRINGING WINTRY WEATHER TO INTERIOR SECTIONS AS IT
MOVES SOUTHEAST OF LONG ISLAND. THE LOW WILL TRACK INTO THE GULF
OF MAINE WEDNESDAY NIGHT. A COLD FRONT WILL CROSS THE REGION LATE
IN THE DAY ON THURSDAY FOLLOWED BY HIGH PRESSURE FRIDAY AND
SATURDAY. A STRONGER COLD FRONT WILL PASS THROUGH ON SUNDAY
FOLLOWED BY HIGH PRESSURE ON MONDAY. ANOTHER FRONTAL SYSTEM MAY
IMPACT THE AREA MONDAY NIGHT INTO TUESDAY.
&&
.NEAR TERM /UNTIL 6 AM WEDNESDAY MORNING/...
CLOUDY SKIES WILL REMAIN AS HIGH PRESSURE MOVES OFF THE NORTHERN
NEW ENGLAND COAST AND WARM AIR ADVECTION ALOFT BEGINS AHEAD OF A
WAVE OF LOW PRESSURE. THIS WAVE WILL BE DEVELOPING OFF THE MID-
ATLANTIC COASTS BY WEDNESDAY MORNING ALONG THAT STALLED FRONT TO
THE SOUTH...EVOLVING AS IT ENCOUNTERS AN INCREASING BAROCLINIC
ENVIRONMENT. WITH INCREASING ISOENTROPIC LIFT...ONSET OF PRECIP
LIKELY 3-6Z FROM SOUTH TO NORTH AFTER NOTING REFLECTIVITY
FORECASTS BY HRRR AND PRECIP FIELDS OF NAM...GFS...ECMWF...AND
CMC. THE INTENSITY OF THE PRECIPITATION INCREASES TOWARDS DAYBREAK
AS THE REGION GETS CLOSER TO THE RIGHT ENTRANCE REGION OF A
160-180 KT JET AROUND 250MB. MID LEVEL FRONTOGENESIS FOCUSED
MOSTLY TO THE NORTH OF THE FORECAST REGION WITH ABRUPT CUTOFFS TO
THE GFS AND NAM SNOWFALL BUT LOWERED TEMPERATURES AND LAYERS
ENOUGH TO ACCOUNT FOR WET BULB COOLING ESPECIALLY AT THE ONSET.
CONCERNING PRECIP TYPE...A COMPLEX FORECAST. GENERALLY THOUGH
EXPECTING SNOW ACROSS THE INTERIOR AREAS...MIXING WITH SLEET TO
THE SOUTHEAST WITH RAIN AND SLEET AT THE COAST. OVERNIGHT...SOME
WARMING IN THE TEMPERATURES ALOFT...GENERALLY BETWEEN 900 AND 700
HPA...WILL PRESENT A LARGE ENOUGH LAYER TO REDUCE THE HYDROMETEORS
TO SLEET ESPECIALLY WITH ANY HIGHER INTENSITY PRECIPITATION. SOME
FREEZING RAIN WILL BE POSSIBLE AS WELL ACROSS A PORTION OF THE
INTERIOR AREAS BUT WILL BE DEPENDENT ON THE AMOUNT OF WET BULB
COOLING AND TEMPERATURES ARE RIGHT NEAR THE FREEZING MARK. SOME
CHANGES ARE POSSIBLE WITH SUBSEQUENT FORECASTS WITH THE
RAIN/SLEET/FREEZING RAIN AND SNOW LINES.
&&
.SHORT TERM /6 AM WEDNESDAY MORNING THROUGH WEDNESDAY NIGHT/...
THE LOW SOUTHEAST OF LONG ISLAND TRAVERSES RIGHT NEAR THE
BENCHMARK OF 40N/-70W AS IT GRADUALLY DEEPENS ON A NORTHEAST
TRACK. THE LOW MOVES TO THE GULF OF MAINE BY WEDNESDAY EVENING
AHEAD OF A DEEPENING UPPER LEVEL TROUGH SINKING INTO THE REGION.
STRONG JET DYNAMICS ALOFT AND THAT RIGHT ENTRANCE REGION WILL MEAN
A LONGER DURATION OF PRECIP...ALTHOUGH NOT MUCH ADDITIONAL
ACCUMULATION EXPECTED BY MID AFTERNOON AND EVENING BY WHICH
TIME...IT WILL BE MOSTLY OVER THE EASTERN SECTIONS OF SOUTHERN CT
AND LONG ISLAND.
WEATHER DRIES WITH A GRADUAL DECREASE IN CLOUDS WEDNESDAY NIGHT.
STRONGER WINDS AT THE SURFACE WILL BE INVOKED AHEAD OF THE NEXT
COLD FRONT AND AN INCREASING PRESSURE GRADIENT.
&&
.LONG TERM /THURSDAY THROUGH TUESDAY/...
A QUIET AND GRADUALLY TURNING COLDER PERIOD AS A SERIES OF COLD
FRONTS PASS THROUGH. FLURRIES OR LIGHT SNOW SHOWERS LOOK TO BE
THE ONLY PCPN UNTIL PERHAPS MON NIGHT INTO TUE. POTENTIALLY THE
COLDEST WEATHER OF THE WINTER ON TAP BY THE MIDDLE OF NEXT WEEK.
LONG WAVE TROUGH ACROSS THE EASTERN 2/3 OF THE CONUS GRADUALLY
DEEPENS INTO THE MIDDLE OF NEXT WEEK AS SHORTWAVE ENERGY ROTATES
INTO THE LONG WAVE AROUND A STRONG POLAR VORTEX OVER HUDSON BAY.
LONG WAVE TROUGH ACROSS THE EASTERN 2/3 OF THE CONUS GRADUALLY
DEEPENS OVER THE WEEKEND AND INTO EARLY NEXT WEEK AS THE UPPER
PATTERN AMPLIFIES. STRONG POLAR VORTEX OVER HUDSON BAY THU MORNING
WILL GRADUALLY WEAKEN AS IT TRACKS EASTWARD...KEEPING THE COLDEST
AIR ASSOCIATED WITH IT TO OUR NORTH. A SHORTWAVE TROUGH CURRENTLY
OVER ALASKA WILL DIVE THROUGH THE NW FLOW THROUGH WESTERN CANADA
AND THE NORTHERN PLAINS FRI AND SAT AIDING IN THE AMPLIFICATION OF
THE TROUGH OVER THE EASTERN US AND RIDGE OUT WEST. THIS ENERGY
ROUNDS THE BASE OF THE TROUGH IN THE GREAT LAKES AND MOVES THROUGH
THE OHIO VALLEY AND NEW ENGLAND SAT NIGHT AND SUN.
AT THE SFC...A COLD FRONT WILL TRACK ACROSS THE REGION THU EVE.
MODELS CONTINUE TO KEEP THE AREA DRY WITH ITS PASSAGE AND KEPT
CONSISTENCY WITH THE PREVIOUS FORECASTS THAT SUPPORT THIS IDEA.
H5 FLOW FLATTENS ON FRI WITH CLIPPER LOW PASSING WELL TO OUR
NORTH. HIGH PRES PASSES S OF THE LOCAL AREA FRI INTO SAT WITH FAIR
AND DRY WEATHER. IMPULSE DIVING OUT OF CENTRAL CANADA WILL RESULT
IN A CHANGE IN THE RECENT PATTERN. LOW PRES IS FORECAST TO TRACK
FROM THE GREAT LAKES THROUGH NORTHERN NEW ENGLAND DRAGGING A
STRONG COLD FRONT ACROSS THE AREA ON SUNDAY.
MEDIUM RANGE GUIDANCE BEGINS TO DIVERGE EARLY NEXT WEEK. THE ECMWF
INDICATES A FAIRLY POTENT SHORTWAVE DIVING FROM CENTRAL CANADA
INTO THE UPPER MISSISSIPPI VALLEY...WHILE THE GFS IS WEAKER. REST
OF THE GUIDANCE IS SPLIT WITH THE UKMET SIMILAR TO THE GFS AND THE
CMC SIMILAR TO THE EC. SINCE THE EC PERFORMS BETTER IN THE MEDIUM
RANGE...FOLLOWED HPC GUIDANCE CLOSELY BEYOND SUNDAY SINCE IT ALSO
INCORPORATES THE EC ENS MEAN.
TEMPS DROP TO SEASONABLE ON FRIDAY BEHIND THE COLD FRONT...THEN
REBOUND TO ABOVE NORMAL IN THE WAA ON SATURDAY. TEMPS FOR SUNDAY
ARE TRICKY DEPENDING ON TIMING OF THE COLD FROPA. BUT WILL
CERTAINLY FALL TO SLIGHTLY BELOW NORMAL ON MONDAY AND TUE.
&&
.AVIATION /21Z TUESDAY THROUGH SUNDAY/...
HIGH PRESSURE OVER THE AREA MOVES NORTHEAST THIS AFTERNOON INTO THIS
EVENING. A WAVE OF LOW PRESSURE APPROACHES FROM THE SOUTHWEST LATE
THIS AFTERNOON AND AFFECTS THE TERMINALS LATE THIS EVENING THROUGH
THE END OF THE FORECAST PERIOD.
VFR CONDITIONS UNTIL THE ONSET OF PRECIPITATION AFTER 03Z.
CONDITIONS LOWER TO MVFR AND THEN IFR IN A MIXTURE OF PRECIPITATION
WITH RAIN AND SLEET AT THE NYC METRO TERMINALS AND A MIX OF RAIN
SNOW AND SLEET FROM KTEB TO KHPN TO KGON...ALL SNOW IS EXPECTED AT
KSWF TIL WEDNESDAY MORNING. A PERIOD OF FREEZING RAIN WILL BE
POSSIBLE AT KSWF AFTER 13Z BEFORE CHANGING TO ALL RAIN. THERE COULD
BE A PERIOD OF FREEZING RAIN AS FAR SOUTH AS COASTAL CONNECTICUT
HOWEVER CONFIDENCE IS LOW AT THIS TIME.
NY METRO ENHANCED AVIATION WEATHER SUPPORT...
DETAILED INFORMATION...INCLUDING HOURLY TAF WIND COMPONENT FCSTS CAN
BE FOUND AT: HTTP:/WWW.ERH.NOAA.GOV/ZNY/N90 (LOWER CASE)
KEWR FCSTER COMMENTS: NO UNSCHEDULED AMENDMENTS EXPECTED THROUGH
02Z. A MIX OF RAIN AND SLEET DEVELOPS AROUND 03Z A TENTH OF AN INCH
OF SLEET IS POSSIBLE. CONDITIONS BECOMING MVFR.
THE AFTERNOON KEWR HAZE POTENTIAL FORECAST IS GREEN...WHICH IMPLIES
SLANT RANGE VISIBILITY 7SM OR GREATER OUTSIDE OF CLOUD.
KJFK FCSTER COMMENTS: NO UNSCHEDULED AMENDMENTS EXPECTED THROUGH
02Z. A MIX OF RAIN AND SLEET DEVELOPS AROUND 03Z A TENTH OF AN INCH
OF SLEET IS POSSIBLE. CONDITIONS BECOMING MVFR.
KLGA FCSTER COMMENTS: NO UNSCHEDULED AMENDMENTS EXPECTED THROUGH
02Z. A MIX OF RAIN AND SLEET DEVELOPS AROUND 03Z A TENTH OF AN INCH
OF SLEET IS POSSIBLE. CONDITIONS BECOMING MVFR.
KTEB FCSTER COMMENTS: NO UNSCHEDULED AMENDMENTS EXPECTED THROUGH
02Z. A MIX OF SNOW AND SLEET DEVELOPS AROUND 03Z. UP TO AN INCH OF
SNOW AND SLEET IS POSSIBLE.
KHPN FCSTER COMMENTS: NO UNSCHEDULED AMENDMENTS EXPECTED THROUGH
02Z. A PERIOD OF SNOW DEVELOPS AROUND 03Z MIXING WITH SLEET AND RAIN
AFTER MIDNIGHT. UP TO 2 INCHES IF SNOW AND SLEET IS POSSIBLE.
KISP FCSTER COMMENTS: NO UNSCHEDULED AMENDMENTS EXPECTED. RAIN
DEVELOPS AFTER 03Z WITH MARGINAL CONDITIONS DEVELOPING.
.OUTLOOK FOR 18Z WEDNESDAY THROUGH SUNDAY...
.WEDNESDAY AFTERNOON...IFR...RAIN ENDING LATE IN THE DAY WITH
IMPROVEMENT TO MARGINAL VFR. WINDS BECOMING WESTERLY.
.WEDNESDAY EVENING...BECOMING VFR EARLY.
.THURSDAY...VFR...W-NW GUSTY WINDS 10-15 G 25KTS.
.FRIDAY-SATURDAY...VFR.
.SUNDAY...MAINLY VFR. POSSIBLY MVFR WITH LIGHT PRECIPITATION WITH
COLD FRONTAL PASSAGE.
&&
.MARINE...
SUB SCA CONDITIONS EXPECTED THROUGH WEDNESDAY WITH INCREASING
NORTHEAST FLOW. NEXT CHANCE OF SCA CONDITIONS COMES WEDNESDAY
NIGHT WITH INCREASING PRESSURE GRADIENT AND WESTERLY FLOW.
SCA CONDS ARE POSSIBLE WED NIGHT AND THU IN RESPONSE TO THE
COMBINATION OF A TIGHT PRESSURE GRADIENT AND COLD AIR ADVECTION
BEHIND THE DEPARTING LOW. A WEAKENING COLD FRONT/TROUGH MOVES ACROSS
THE WATERS THU NIGHT WITH MARGINAL SCA CONDS POSSIBLE...MAINLY ON
THE OCEAN WATERS. SUB-ADVSY CONDS RETURN ON FRI WITH A WEAKENING
PRES GRADIENT AS HIGH PRES BUILDS INTO THE REGION. THE GRADIENT WILL
TIGHTEN ONCE AGAIN FRI NIGHT AND SAT AS HIGH PRES BUILDS TO THE S OF
THE AREA AND LOW PRES TRACKS WELL TO THE NORTH. SCA CONDS ARE
EXPECTED ONCE AGAIN. AFTER A BRIEF LULL SAT NIGHT INTO SUN...STRONG
SCA CONDS WILL RETURN YET AGAIN AS A STRONG COLD FRONT SWEEPS ACROSS
THE AREA.
&&
.HYDROLOGY...
QPF OF AROUND 0.4 TO 0.6 INCH LIQUID EQUIVALENT EXPECTED TONIGHT
INTO WED WITH HIGHER AMOUNTS NEAR THE COAST. MOST OF THIS SHOULD
FALL AS SNOW AWAY FROM THE IMMEDIATE CT COAST AND NYC METRO AREAS.
NO SIGNIFICANT PRECIPITATION IS EXPECTED THROUGH THE REMAINDER OF
THE WEEK.
&&
.OKX WATCHES/WARNINGS/ADVISORIES...
CT...WINTER WEATHER ADVISORY FROM MIDNIGHT TONIGHT TO 4 PM EST
WEDNESDAY FOR CTZ005>010.
NY...WINTER WEATHER ADVISORY FROM MIDNIGHT TONIGHT TO 4 PM EST
WEDNESDAY FOR NYZ067>071.
NJ...WINTER WEATHER ADVISORY FROM MIDNIGHT TONIGHT TO 4 PM EST
WEDNESDAY FOR NJZ002-004-103>105-107.
MARINE...NONE.
&&
$$
SYNOPSIS...24/JM
NEAR TERM...JM
SHORT TERM...JM
LONG TERM...24
AVIATION...MET
MARINE...24/JM
HYDROLOGY...24/JM
AREA FORECAST DISCUSSION
NWS NEW YORK NY
417 PM EST TUE JAN 15 2013
.SYNOPSIS...
LOW PRESSURE WILL RIDE ALONG THE STALLED FRONT TONIGHT INTO
WEDNESDAY...BRINGING WINTRY WEATHER TO INTERIOR SECTIONS AS IT
MOVES SOUTHEAST OF LONG ISLAND AND INTO GULF OF MAINE WEDNESDAY
NIGHT. A COLD FRONT WILL CROSS THE REGION LATE IN THE DAY ON
THURSDAY FOLLOWED BY HIGH PRESSURE FRIDAY AND SATURDAY. A STRONGER
COLD FRONT WILL PASS THROUGH ON SUNDAY FOLLOWED BY HIGH PRESSURE
ON MONDAY. ANOTHER FRONTAL SYSTEM MAY IMPACT THE AREA MONDAY NIGHT
INTO TUESDAY.
&&
.NEAR TERM /UNTIL 6 AM WEDNESDAY MORNING/...
CLOUDY SKIES WILL REMAIN AS HIGH PRESSURE MOVES OFF THE NORTHERN
NEW ENGLAND COAST AND WARM AIR ADVECTION ALOFT BEGINS AHEAD OF A
WAVE OF LOW PRESSURE. THIS WAVE WILL BE DEVELOPING OFF THE MID-
ATLANTIC COASTS BY WEDNESDAY MORNING ALONG THAT STALLED FRONT TO
THE SOUTH...EVOLVING AS IT ENCOUNTERS AN INCREASING BAROCLINIC
ENVIRONMENT. WITH INCREASING ISOENTROPIC LIFT...ONSET OF PRECIP
LIKELY 3-6Z FROM SOUTH TO NORTH AFTER NOTING REFLECTIVITY
FORECASTS BY HRRR AND PRECIP FIELDS OF NAM...GFS...ECMWF...AND
CMC. THE INTENSITY OF THE PRECIPITATION INCREASES TOWARDS DAYBREAK
AS THE REGION GETS CLOSER TO THE RIGHT ENTRANCE REGION OF A
160-180 KT JET AROUND 250MB. MID LEVEL FRONTOGENESIS FOCUSED
MOSTLY TO THE NORTH OF THE FORECAST REGION WITH ABRUPT CUTOFFS TO
THE GFS AND NAM SNOWFALL BUT LOWERED TEMPERATURES AND LAYERS
ENOUGH TO ACCOUNT FOR WET BULB COOLING ESPECIALLY AT THE ONSET.
CONCERNING PRECIP TYPE...A COMPLEX FORECAST. GENERALLY THOUGH
EXPECTING A MIX OF SNOW ACROSS THE INTERIOR AREAS...MIXING WITH
SLEET TO THE SOUTHEAST WITH RAIN AND SLEET AT THE COAST.
OVERNIGHT...SOME WARMING IN THE TEMPERATURES ALOFT...GENERALLY
BETWEEN 700 AND 900 HPA...WILL PRESENT A LARGE ENOUGH LAYER TO
REDUCE THE HYDROMETEORS TO SLEET ESPECIALLY WITH ANY HIGHER
INTENSITY PRECIPITATION. SOME FREEZING RAIN WILL BE POSSIBLE AS
WELL ACROSS A PORTION OF THE INTERIOR AREAS BUT WILL BE DEPENDENT
ON THE AMOUNT OF WET BULB COOLING AND TEMPERATURES ARE RIGHT NEAR
THE FREEZING MARK. SOME CHANGES ARE POSSIBLE WITH SUBSEQUENT
FORECASTS WITH THE RAIN/SLEET/FREEZING RAIN AND SNOW LINES.
&&
.SHORT TERM /6 AM WEDNESDAY MORNING THROUGH WEDNESDAY NIGHT/...
THE LOW SOUTHEAST OF LONG ISLAND TRAVERSES RIGHT NEAR THE
BENCHMARK OF 40N/-70W AS IT GRADUALLY DEEPENS ON A NORTHEAST
TRACK. THE LOW MOVES TO THE GULF OF MAINE BY WEDNESDAY EVENING
AHEAD OF A DEEPENING UPPER LEVEL TROUGH SINKING INTO THE REGION.
STRONG JET DYNAMICS ALOFT AND THAT RIGHT ENTRANCE REGION WILL MEAN
A LONGER DURATION OF PRECIP...ALTHOUGH NOT MUCH ADDITIONAL
ACCUMULATION EXPECTED BY MID AFTERNOON AND EVENING BY WHICH
TIME...IT WILL BE MOSTLY OVER THE EASTERN SECTIONS OF SOUTHERN CT
AND LONG ISLAND.
WEATHER DRIES WITH A GRADUAL DECREASE IN CLOUDS WEDNESDAY NIGHT.
STRONGER WINDS AT THE SURFACE WILL BE INVOKED AHEAD OF THE NEXT
COLD FRONT AND AN INCREASING PRESSURE GRADIENT.
&&
.LONG TERM /THURSDAY THROUGH TUESDAY/...
A QUIET AND GRADUALLY TURNING COLDER PERIOD AS A SERIES OF COLD
FRONTS PASS THROUGH. FLURRIES OR LIGHT SNOW SHOWERS LOOK TO BE
THE ONLY PCPN UNTIL PERHAPS MON NIGHT INTO TUE. POTENTIALLY THE
COLDEST WEATHER OF THE WINTER ON TAP BY THE MIDDLE OF NEXT WEEK.
LONG WAVE TROUGH ACROSS THE EASTERN 2/3 OF THE CONUS GRADUALLY
DEEPENS INTO THE MIDDLE OF NEXT WEEK AS SHORTWAVE ENERGY ROTATES
INTO THE LONG WAVE AROUND A STRONG POLAR VORTEX OVER HUDSON BAY.
LONG WAVE TROUGH ACROSS THE EASTERN 2/3 OF THE CONUS GRADUALLY
DEEPENS OVER THE WEEKEND AND INTO EARLY NEXT WEEK AS THE UPPER
PATTERN AMPLIFIES. STRONG POLAR VORTEX OVER HUDSON BAY THU MORNING
WILL GRADUALLY WEAKEN AS IT TRACKS EASTWARD...KEEPING THE COLDEST
AIR ASSOCIATED WITH IT TO OUR NORTH. A SHORTWAVE TROUGH CURRENTLY
OVER ALASKA WILL DIVE THROUGH THE NW FLOW THROUGH WESTERN CANADA
AND THE NORTHERN PLAINS FRI AND SAT AIDING IN THE AMPLIFICATION OF
THE TROUGH OVER THE EASTERN US AND RIDGE OUT WEST. THIS ENERGY
ROUNDS THE BASE OF THE TROUGH IN THE GREAT LAKES AND MOVES THROUGH
THE OHIO VALLEY AND NEW ENGLAND SAT NIGHT AND SUN.
AT THE SFC...A COLD FRONT WILL TRACK ACROSS THE REGION THU EVE.
MODELS CONTINUE TO KEEP THE AREA DRY WITH ITS PASSAGE AND KEPT
CONSISTENCY WITH THE PREVIOUS FORECASTS THAT SUPPORT THIS IDEA.
H5 FLOW FLATTENS ON FRI WITH CLIPPER LOW PASSING WELL TO OUR
NORTH. HIGH PRES PASSES S OF THE LOCAL AREA FRI INTO SAT WITH FAIR
AND DRY WEATHER. IMPULSE DIVING OUT OF CENTRAL CANADA WILL RESULT
IN A CHANGE IN THE RECENT PATTERN. LOW PRES IS FORECAST TO TRACK
FROM THE GREAT LAKES THROUGH NORTHERN NEW ENGLAND DRAGGING A
STRONG COLD FRONT ACROSS THE AREA ON SUNDAY.
MEDIUM RANGE GUIDANCE BEGINS TO DIVERGE EARLY NEXT WEEK. THE ECMWF
INDICATES A FAIRLY POTENT SHORTWAVE DIVING FROM CENTRAL CANADA
INTO THE UPPER MISSISSIPPI VALLEY...WHILE THE GFS IS WEAKER. REST
OF THE GUIDANCE IS SPLIT WITH THE UKMET SIMILAR TO THE GFS AND THE
CMC SIMILAR TO THE EC. SINCE THE EC PERFORMS BETTER IN THE MEDIUM
RANGE...FOLLOWED HPC GUIDANCE CLOSELY BEYOND SUNDAY SINCE IT ALSO
INCORPORATES THE EC ENS MEAN.
TEMPS DROP TO SEASONABLE ON FRIDAY BEHIND THE COLD FRONT...THEN
REBOUND TO ABOVE NORMAL IN THE WAA ON SATURDAY. TEMPS FOR SUNDAY
ARE TRICKY DEPENDING ON TIMING OF THE COLD FROPA. BUT WILL
CERTAINLY FALL TO SLIGHTLY BELOW NORMAL ON MONDAY AND TUE.
&&
.AVIATION /21Z TUESDAY THROUGH SUNDAY/...
HIGH PRESSURE OVER THE AREA MOVES NORTHEAST THIS AFTERNOON INTO THIS
EVENING. A WAVE OF LOW PRESSURE APPROACHES FROM THE SOUTHWEST LATE
THIS AFTERNOON AND AFFECTS THE TERMINALS LATE THIS EVENING THROUGH
THE END OF THE FORECAST PERIOD.
VFR CONDITIONS UNTIL THE ONSET OF PRECIPITATION AFTER 03Z.
CONDITIONS LOWER TO MVFR AND THEN IFR IN A MIXTURE OF PRECIPITATION
WITH RAIN AND SLEET AT THE NYC METRO TERMINALS AND A MIX OF RAIN
SNOW AND SLEET FROM KTEB TO KHPN TO KGON...ALL SNOW IS EXPECTED AT
KSWF TIL WEDNESDAY MORNING. A PERIOD OF FREEZING RAIN WILL BE
POSSIBLE AT KSWF AFTER 13Z BEFORE CHANGING TO ALL RAIN. THERE COULD
BE A PERIOD OF FREEZING RAIN AS FAR SOUTH AS COASTAL CONNECTICUT
HOWEVER CONFIDENCE IS LOW AT THIS TIME.
NY METRO ENHANCED AVIATION WEATHER SUPPORT...
DETAILED INFORMATION...INCLUDING HOURLY TAF WIND COMPONENT FCSTS CAN
BE FOUND AT: HTTP:/WWW.ERH.NOAA.GOV/ZNY/N90 (LOWER CASE)
KEWR FCSTER COMMENTS: NO UNSCHEDULED AMENDMENTS EXPECTED THROUGH
02Z. A MIX OF RAIN AND SLEET DEVELOPS AROUND 03Z A TENTH OF AN INCH
OF SLEET IS POSSIBLE. CONDITIONS BECOMING MVFR.
THE AFTERNOON KEWR HAZE POTENTIAL FORECAST IS GREEN...WHICH IMPLIES
SLANT RANGE VISIBILITY 7SM OR GREATER OUTSIDE OF CLOUD.
KJFK FCSTER COMMENTS: NO UNSCHEDULED AMENDMENTS EXPECTED THROUGH
02Z. A MIX OF RAIN AND SLEET DEVELOPS AROUND 03Z A TENTH OF AN INCH
OF SLEET IS POSSIBLE. CONDITIONS BECOMING MVFR.
KLGA FCSTER COMMENTS: NO UNSCHEDULED AMENDMENTS EXPECTED THROUGH
02Z. A MIX OF RAIN AND SLEET DEVELOPS AROUND 03Z A TENTH OF AN INCH
OF SLEET IS POSSIBLE. CONDITIONS BECOMING MVFR.
KTEB FCSTER COMMENTS: NO UNSCHEDULED AMENDMENTS EXPECTED THROUGH
02Z. A MIX OF SNOW AND SLEET DEVELOPS AROUND 03Z. UP TO AN INCH OF
SNOW AND SLEET IS POSSIBLE.
KHPN FCSTER COMMENTS: NO UNSCHEDULED AMENDMENTS EXPECTED THROUGH
02Z. A PERIOD OF SNOW DEVELOPS AROUND 03Z MIXING WITH SLEET AND RAIN
AFTER MIDNIGHT. UP TO 2 INCHES IF SNOW AND SLEET IS POSSIBLE.
KISP FCSTER COMMENTS: NO UNSCHEDULED AMENDMENTS EXPECTED. RAIN
DEVELOPS AFTER 03Z WITH MARGINAL CONDITIONS DEVELOPING.
.OUTLOOK FOR 18Z WEDNESDAY THROUGH SUNDAY...
.WEDNESDAY AFTERNOON...IFR...RAIN ENDING LATE IN THE DAY WITH
IMPROVEMENT TO MARGINAL VFR. WINDS BECOMING WESTERLY.
.WEDNESDAY EVENING...BECOMING VFR EARLY.
.THURSDAY...VFR...W-NW GUSTY WINDS 10-15 G 25KTS.
.FRIDAY-SATURDAY...VFR.
.SUNDAY...MAINLY VFR. POSSIBLY MVFR WITH LIGHT PRECIPITATION WITH
COLD FRONTAL PASSAGE.
&&
.MARINE...
SUB SCA CONDITIONS EXPECTED THROUGH WEDNESDAY WITH INCREASING
NORTHEAST FLOW. NEXT CHANCE OF SCA CONDITIONS COMES WEDNESDAY
NIGHT WITH INCREASING PRESSURE GRADIENT AND WESTERLY FLOW.
SCA CONDS ARE POSSIBLE WED NIGHT AND THU IN RESPONSE TO THE
COMBINATION OF A TIGHT PRESSURE GRADIENT AND COLD AIR ADVECTION
BEHIND THE DEPARTING LOW. A WEAKENING COLD FRONT/TROUGH MOVES ACROSS
THE WATERS THU NIGHT WITH MARGINAL SCA CONDS POSSIBLE...MAINLY ON
THE OCEAN WATERS. SUB-ADVSY CONDS RETURN ON FRI WITH A WEAKENING
PRES GRADIENT AS HIGH PRES BUILDS INTO THE REGION. THE GRADIENT WILL
TIGHTEN ONCE AGAIN FRI NIGHT AND SAT AS HIGH PRES BUILDS TO THE S OF
THE AREA AND LOW PRES TRACKS WELL TO THE NORTH. SCA CONDS ARE
EXPECTED ONCE AGAIN. AFTER A BRIEF LULL SAT NIGHT INTO SUN...STRONG
SCA CONDS WILL RETURN YET AGAIN AS A STRONG COLD FRONT SWEEPS ACROSS
THE AREA.
&&
.HYDROLOGY...
QPF OF AROUND 0.4 TO 0.6 INCH LIQUID EQUIVALENT EXPECTED TONIGHT
INTO WED WITH HIGHER AMOUNTS NEAR THE COAST. MOST OF THIS SHOULD
FALL AS SNOW AWAY FROM THE IMMEDIATE CT COAST AND NYC METRO AREAS.
NO SIGNIFICANT PRECIPITATION IS EXPECTED THROUGH THE REMAINDER OF
THE WEEK.
&&
.OKX WATCHES/WARNINGS/ADVISORIES...
CT...WINTER WEATHER ADVISORY FROM MIDNIGHT TONIGHT TO 4 PM EST
WEDNESDAY FOR CTZ005>010.
NY...WINTER WEATHER ADVISORY FROM MIDNIGHT TONIGHT TO 4 PM EST
WEDNESDAY FOR NYZ067>071.
NJ...WINTER WEATHER ADVISORY FROM MIDNIGHT TONIGHT TO 4 PM EST
WEDNESDAY FOR NJZ002-004-103>105-107.
MARINE...NONE.
&&
$$
SYNOPSIS...24/JM
NEAR TERM...JM
SHORT TERM...JM
LONG TERM...24
AVIATION...MET
MARINE...24/JM
HYDROLOGY...24/JM
AREA FORECAST DISCUSSION
NWS INDIANAPOLIS IN
513 PM EST TUE JAN 15 2013
.UPDATE...
THE AVIATION SECTION HAS BEEN UPDATED BELOW.
&&
.SYNOPSIS...
ISSUED AT 212 PM EST TUE JAN 15 2013
QUIET WEATHER CAN BE EXPECTED UNDER HIGH PRESSURE THROUGH THE END
OF THE WEEK WITH TEMPERATURES NEAR NORMAL FOR THIS TIME OF YEAR.
COULD SEE A BRIEF WARM UP SATURDAY INTO THE 40S BEFORE
TEMPERATURES DROP BACK TO NORMAL SUNDAY AND THEN GET VERY COLD TO
START OUT THE WEEK. A CLIPPER SYSTEM WILL MOVE THROUGH SUNDAY
NIGHT THROUGH MONDAY NIGHT BRINGING CHANCES FOR SNOW.
&&
.NEAR TERM /TONIGHT/...
ISSUED AT 212 PM EST TUE JAN 15 2013
SKIES SHOULD START OUT MOSTLY CLOUDY WITH A LOW PRESSURE SYSTEM
MOVING NORTHEAST OUT OF THE GULF AND THROUGH THE SOUTHEASTERN U.S. A
BIT OF MODEL DISAGREEMENT OVER HOW FAR NORTH PRECIPITATION
ASSOCIATED WITH THIS SYSTEM WILL GET DESPITE SIMILAR POSITIONS AND
STRENGTH FOR THE LOW PRESSURE CENTER. THE RAP AND GEM WERE THE
FURTHEST NORTH AND BRING THE PRECIP INTO THE FAR SOUTHEASTERN
COUNTIES. THE GFS KEEPS THE PRECIP WELL TO THE SOUTH...WHILE THE NAM
AND 0Z ECMWF JUST CLIP THE FAR SOUTHEAST WITH A HUNDREDTH OF QPF.
WITH THE VARIETY OF SOLUTIONS SHOULD CARRY A LOW CHANCE POP IN THE
FAR SOUTHEAST WITH DRY WEATHER BUT MOSTLY CLOUDY SKIES ELSEWHERE.
WENT WITH LOWS A DEGREE OR TWO BELOW GUIDANCE WITH EXPECTED COLD
ADVECTION.
&&
.SHORT TERM /WEDNESDAY THROUGH FRIDAY/...
ISSUED AT 212 PM EST TUE JAN 15 2013
HIGH PRESSURE WILL REMAIN OVER THE AREA THROUGH THE SHORT TERM. A
LOW PRESSURE SYSTEM MOVING ACROSS THE HUDSON BAY WILL DRAG A COLD
FRONT ACROSS THE GREAT LAKES WEDNESDAY AND WEDNESDAY NIGHT...BUT IT LOOKS
LIKE ALL THE FORCING ASSOCIATED WITH IT WILL STAY WELL NORTH OF THE
AREA. ANOTHER SOUTHERN LOW PRESSURE SYSTEM WHICH WILL MOVE ACROSS
THE SOUTHEAST U.S. DURING THE SAME TIME APPEARS TO BE TOO FAR SOUTH
TO IMPACT POPS HERE. GUIDANCE IS IN GOOD AGREEMENT AND WILL USE AN
AVERAGE WHICH RESULTS IN NEAR NORMAL TEMPERATURES AND DRY WEATHER.
&&
.LONG TERM /FRIDAY NIGHT THROUGH TUESDAY/...
ISSUED AT 248 PM EST TUE JAN 15 2013
FOCUS OF THE EXTENDED PERIOD REMAINS ON THE ARRIVAL OF WHAT
INCREASINGLY APPEARS TO BE THE COLDEST AIRMASS OF THE SEASON AS A
PIEICE OF THE POLAR VORTEX BREAKS OFF AND AMPLIFIES THE UPPER
TROUGH OVER THE EASTERN PART OF THE COUNTRY.
WARMEST DAY OF THE PERIOD WILL BE SATURDAY AS SOUTHERLY FLOW AHEAD
OF A COLD FRONT ENABLES TEMPS TO RISE INTO THE 40S ACROSS THE
FORECAST AREA. LOW PRESSURE WILL TRACK THROUGH THE GREAT LAKES
SATURDAY NIGHT AND BRING THE COLD FRONT THROUGH CENTRAL INDIANA BY
EARLY SUNDAY. THE FRONT WILL USHER IN THE INITIAL SHOT OF COLDER
AIR...AS TEMPS ARE LIKELY TO FALL BACK INTO THE 20S AND LOWER 30S.
PASSAGE OF THE FRONT LOOKS TO BE DRY AS DEEPER MOISTURE IS FOCUSED
CLOSER TO THE LOW ACROSS THE GREAT LAKES. ARCTIC FRONT SET TO DIVE
INTO THE REGION ON MONDAY...USHERING IN MUCH COLDER AIR AS 850MB
TEMPS NOSEDIVE. ANTICIPATE SNOW SHOWERS TO ACCOMPANY THE FRONTAL
PASSAGE AND AS WIND FLOW ALIGNS TO THE NORTHWEST IN ITS WAKE...
LIKELY TO SEE SOME IMPACTS FROM LAKE ENHANCEMENT SNOW SHOWERS
THROUGH MONDAY NIGHT.
THE MUCH GREATER IMPACT WITH THE FRONTAL PASSAGE WILL BE TO
TEMPERATURES AS 850MB TEMPS ON BOTH THE ECMWF AND OP GFS FALL INTO
THE -23 TO -21C RANGE BY TUESDAY. IF THESE NUMBERS EVEN COME CLOSE
TO VERIFYING...HIGH TEMPS ON TUESDAY ARE LIKELY TO STRUGGLE INTO
THE 10-15 DEGREE RANGE AND PROVIDE CENTRAL INDIANA WITH THE
COLDEST AIR OF THE SEASON TO DATE. KNOWING HOW MODELS THIS FAR OUT
TEND TO UNDEROD THE DEPTH OF ARCTIC COLD AND WITH GROWING
CONFIDENCE IN THE INTENSITY OF THE COLD AIRMASS...HAVE CHOSEN TO
UNDERCUT ALLBLEND TEMPS BY 3 TO 4 DEGREES FOR BOTH MONDAY AND
TUESDAY. LOWS MAY BE DOWN NEAR ZERO BY TUESDAY NIGHT.
&&
.AVIATION /DISCUSSION FOR 160000Z TAF ISSUANCE/...
ISSUED AT 508 PM EST TUE JAN 15 2013
NO SIGNIFICANT CHANGES. VFR CONDITIONS ANTICIPATED THROUGHOUT THE
FORECAST PERIOD.
CLOUD COVERAGE WILL CONTINUE TO INCREASE ACROSS CENTRAL INDIANA
AS LOW PRESSURE MOVES OUT OF THE GULF COAST REGION MOVES ACROSS THE
SOUTHERN TENNESSEE VALLEY THIS EVENING. MOISTURE PROFILES HAVE
ALREADY BEGUN TO DEEPEN THIS EVENING WITH CEILINGS AROUND 6-8KFT.
AS THE LOW PRESSURE SHIFTS INTO THE SOUTHERN APPALACHIANS LATE
TONIGHT...MOISTURE ALOFT WILL ALSO BEGIN TO DEPART OFF TO THE EAST
AND CEILINGS ARE EXPECTED TO LIFT AND SCATTER IN THE HOURS
APPROACHING DAYBREAK. HIGH PRESSURE RIDGE THEN BUILDS INTO THE
REGION WEDNESDAY WITH BROAD SUBSIDENCE. WILL SEE SKIES BECOME
MOSTLY CLEAR. LIGHT AND VARIABLE WINDS LATE TONIGHT WILL SHIFT TO
W/SW AND INCREASE TO NEAR 10KTS WEDNESDAY.
&&
.IND WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...CP
NEAR TERM...CP
SHORT TERM...CP
LONG TERM....RYAN
AVIATION...SMF
AREA FORECAST DISCUSSION
NWS INDIANAPOLIS IN
323 PM EST TUE JAN 15 2013
.UPDATE...
THE AVIATION SECTION HAS BEEN UPDATED BELOW.
&&
.SYNOPSIS...
ISSUED AT 212 PM EST TUE JAN 15 2013
QUIET WEATHER CAN BE EXPECTED UNDER HIGH PRESSURE THROUGH THE END
OF THE WEEK WITH TEMPERATURES NEAR NORMAL FOR THIS TIME OF YEAR.
COULD SEE A BRIEF WARM UP SATURDAY INTO THE 40S BEFORE
TEMPERATURES DROP BACK TO NORMAL SUNDAY AND THEN GET VERY COLD TO
START OUT THE WEEK. A CLIPPER SYSTEM WILL MOVE THROUGH SUNDAY
NIGHT THROUGH MONDAY NIGHT BRINGING CHANCES FOR SNOW.
&&
.NEAR TERM /TONIGHT/...
ISSUED AT 212 PM EST TUE JAN 15 2013
SKIES SHOULD START OUT MOSTLY CLOUDY WITH A LOW PRESSURE SYSTEM
MOVING NORTHEAST OUT OF THE GULF AND THROUGH THE SOUTHEASTERN U.S. A
BIT OF MODEL DISAGREEMENT OVER HOW FAR NORTH PRECIPITATION
ASSOCIATED WITH THIS SYSTEM WILL GET DESPITE SIMILAR POSITIONS AND
STRENGTH FOR THE LOW PRESSURE CENTER. THE RAP AND GEM WERE THE
FURTHEST NORTH AND BRING THE PRECIP INTO THE FAR SOUTHEASTERN
COUNTIES. THE GFS KEEPS THE PRECIP WELL TO THE SOUTH...WHILE THE NAM
AND 0Z ECMWF JUST CLIP THE FAR SOUTHEAST WITH A HUNDREDTH OF QPF.
WITH THE VARIETY OF SOLUTIONS SHOULD CARRY A LOW CHANCE POP IN THE
FAR SOUTHEAST WITH DRY WEATHER BUT MOSTLY CLOUDY SKIES ELSEWHERE.
WENT WITH LOWS A DEGREE OR TWO BELOW GUIDANCE WITH EXPECTED COLD
ADVECTION.
&&
.SHORT TERM /WEDNESDAY THROUGH FRIDAY/...
ISSUED AT 212 PM EST TUE JAN 15 2013
HIGH PRESSURE WILL REMAIN OVER THE AREA THROUGH THE SHORT TERM. A
LOW PRESSURE SYSTEM MOVING ACROSS THE HUDSON BAY WILL DRAG A COLD
FRONT ACROSS THE GREAT LAKES WEDNESDAY AND WEDNESDAY NIGHT...BUT IT LOOKS
LIKE ALL THE FORCING ASSOCIATED WITH IT WILL STAY WELL NORTH OF THE
AREA. ANOTHER SOUTHERN LOW PRESSURE SYSTEM WHICH WILL MOVE ACROSS
THE SOUTHEAST U.S. DURING THE SAME TIME APPEARS TO BE TOO FAR SOUTH
TO IMPACT POPS HERE. GUIDANCE IS IN GOOD AGREEMENT AND WILL USE AN
AVERAGE WHICH RESULTS IN NEAR NORMAL TEMPERATURES AND DRY WEATHER.
&&
.LONG TERM /FRIDAY NIGHT THROUGH TUESDAY/...
ISSUED AT 248 PM EST TUE JAN 15 2013
FOCUS OF THE EXTENDED PERIOD REMAINS ON THE ARRIVAL OF WHAT
INCREASINGLY APPEARS TO BE THE COLDEST AIRMASS OF THE SEASON AS A
PIEICE OF THE POLAR VORTEX BREAKS OFF AND AMPLIFIES THE UPPER
TROUGH OVER THE EASTERN PART OF THE COUNTRY.
WARMEST DAY OF THE PERIOD WILL BE SATURDAY AS SOUTHERLY FLOW AHEAD
OF A COLD FRONT ENABLES TEMPS TO RISE INTO THE 40S ACROSS THE
FORECAST AREA. LOW PRESSURE WILL TRACK THROUGH THE GREAT LAKES
SATURDAY NIGHT AND BRING THE COLD FRONT THROUGH CENTRAL INDIANA BY
EARLY SUNDAY. THE FRONT WILL USHER IN THE INITIAL SHOT OF COLDER
AIR...AS TEMPS ARE LIKELY TO FALL BACK INTO THE 20S AND LOWER 30S.
PASSAGE OF THE FRONT LOOKS TO BE DRY AS DEEPER MOISTURE IS FOCUSED
CLOSER TO THE LOW ACROSS THE GREAT LAKES. ARCTIC FRONT SET TO DIVE
INTO THE REGION ON MONDAY...USHERING IN MUCH COLDER AIR AS 850MB
TEMPS NOSEDIVE. ANTICIPATE SNOW SHOWERS TO ACCOMPANY THE FRONTAL
PASSAGE AND AS WIND FLOW ALIGNS TO THE NORTHWEST IN ITS WAKE...
LIKELY TO SEE SOME IMPACTS FROM LAKE ENHANCEMENT SNOW SHOWERS
THROUGH MONDAY NIGHT.
THE MUCH GREATER IMPACT WITH THE FRONTAL PASSAGE WILL BE TO
TEMPERATURES AS 850MB TEMPS ON BOTH THE ECMWF AND OP GFS FALL INTO
THE -23 TO -21C RANGE BY TUESDAY. IF THESE NUMBERS EVEN COME CLOSE
TO VERIFYING...HIGH TEMPS ON TUESDAY ARE LIKELY TO STRUGGLE INTO
THE 10-15 DEGREE RANGE AND PROVIDE CENTRAL INDIANA WITH THE
COLDEST AIR OF THE SEASON TO DATE. KNOWING HOW MODELS THIS FAR OUT
TEND TO UNDEROD THE DEPTH OF ARCTIC COLD AND WITH GROWING
CONFIDENCE IN THE INTENSITY OF THE COLD AIRMASS...HAVE CHOSEN TO
UNDERCUT ALLBLEND TEMPS BY 3 TO 4 DEGREES FOR BOTH MONDAY AND
TUESDAY. LOWS MAY BE DOWN NEAR ZERO BY TUESDAY NIGHT.
&&
.AVIATION /DISCUSSION FOR 152100Z TAF UPDATE/...
ISSUED AT 323 PM EST TUE JAN 15 2013
NO SIGNIFICANT CHANGES...PREVIOUS DICUSSION FOLLOWS.
VFR CONDITIONS ANTICIPATED THROUGHOUT THE FORECAST.
MID AND HIGH LEVEL CLOUD COVERAGE WILL STEADILY INCREASE ACROSS
CENTRAL INDIANA THIS AFTERNOON AS LOW PRESSURE MOVES OUT OF THE
GULF COAST REGION AND INTO THE LOWER TENNESSEE VALLEY THIS
EVENING. LARGE AREA OF CEILINGS AROUND 10KFT OVER THE OZARKS
QUICKLY EXPANDING NORTHEAST AND SHOULD ENVELOP THE TERMINALS BY
MID AFTERNOON. MOISTURE PROFILE DEEPENS THIS EVENING WITH CEILINGS
LIKELY TO FALL TO 6-8KFT FOR SEVERAL HOURS...ESPECIALLY AT KBMG/
KHUF/KIND. BOUNDARY LAYER HOWEVER REMAINS DRY WITH A PERSISTENT
LOW LEVEL FLOW FROM THE NORTHEAST.
AS THE LOW PRESSURE SHIFTS INTO THE SOUTHERN APPALACHIANS LATE
TONIGHT...MOISTURE ALOFT WILL ALSO BEGIN TO DEPART OFF TO THE EAST
AND CEILINGS ARE EXPECTED TO LIFT AND SCATTER IN THE HOURS
APPROACHING DAYBREAK. HIGH PRESSURE RIDGE THEN BUILDS INTO THE
REGION WEDNESDAY WITH BROAD SUBSIDENCE AND WILL SEE SKIES BECOME
MOSTLY CLEAR. LIGHT AND VARIABLE WINDS LATE TONIGHT WILL SHIFT TO
W/SW AND INCREASE TO NEAR 10KTS WEDNESDAY.
&&
.IND WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
SYNOPSIS...CP
NEAR TERM...CP
SHORT TERM...CP
LONG TERM....RYAN
AVIATION...RYAN
AREA FORECAST DISCUSSION
NWS INDIANAPOLIS IN
248 PM EST TUE JAN 15 2013
.UPDATE...
THE LONG TERM SECTION HAS BEEN UPDATED BELOW.
&&
.SYNOPSIS...
ISSUED AT 212 PM EST TUE JAN 15 2013
QUIET WEATHER CAN BE EXPECTED UNDER HIGH PRESSURE THROUGH THE END
OF THE WEEK WITH TEMPERATURES NEAR NORMAL FOR THIS TIME OF YEAR.
COULD SEE A BRIEF WARM UP SATURDAY INTO THE 40S BEFORE
TEMPERATURES DROP BACK TO NORMAL SUNDAY AND THEN GET VERY COLD TO
START OUT THE WEEK. A CLIPPER SYSTEM WILL MOVE THROUGH SUNDAY
NIGHT THROUGH MONDAY NIGHT BRINGING CHANCES FOR SNOW.
&&
.NEAR TERM /TONIGHT/...
ISSUED AT 212 PM EST TUE JAN 15 2013
SKIES SHOULD START OUT MOSTLY CLOUDY WITH A LOW PRESSURE SYSTEM
MOVING NORTHEAST OUT OF THE GULF AND THROUGH THE SOUTHEASTERN U.S. A
BIT OF MODEL DISAGREEMENT OVER HOW FAR NORTH PRECIPITATION
ASSOCIATED WITH THIS SYSTEM WILL GET DESPITE SIMILAR POSITIONS AND
STRENGTH FOR THE LOW PRESSURE CENTER. THE RAP AND GEM WERE THE
FURTHEST NORTH AND BRING THE PRECIP INTO THE FAR SOUTHEASTERN
COUNTIES. THE GFS KEEPS THE PRECIP WELL TO THE SOUTH...WHILE THE NAM
AND 0Z ECMWF JUST CLIP THE FAR SOUTHEAST WITH A HUNDREDTH OF QPF.
WITH THE VARIETY OF SOLUTIONS SHOULD CARRY A LOW CHANCE POP IN THE
FAR SOUTHEAST WITH DRY WEATHER BUT MOSTLY CLOUDY SKIES ELSEWHERE.
WENT WITH LOWS A DEGREE OR TWO BELOW GUIDANCE WITH EXPECTED COLD
ADVECTION.
&&
.SHORT TERM /WEDNESDAY THROUGH FRIDAY/...
ISSUED AT 212 PM EST TUE JAN 15 2013
HIGH PRESSURE WILL REMAIN OVER THE AREA THROUGH THE SHORT TERM. A
LOW PRESSURE SYSTEM MOVING ACROSS THE HUDSON BAY WILL DRAG A COLD
FRONT ACROSS THE GREAT LAKES WEDNESDAY AND WEDNESDAY NIGHT...BUT IT LOOKS
LIKE ALL THE FORCING ASSOCIATED WITH IT WILL STAY WELL NORTH OF THE
AREA. ANOTHER SOUTHERN LOW PRESSURE SYSTEM WHICH WILL MOVE ACROSS
THE SOUTHEAST U.S. DURING THE SAME TIME APPEARS TO BE TOO FAR SOUTH
TO IMPACT POPS HERE. GUIDANCE IS IN GOOD AGREEMENT AND WILL USE AN
AVERAGE WHICH RESULTS IN NEAR NORMAL TEMPERATURES AND DRY WEATHER.
&&
.LONG TERM /FRIDAY NIGHT THROUGH TUESDAY/...
ISSUED AT 248 PM EST TUE JAN 15 2013
FOCUS OF THE EXTENDED PERIOD REMAINS ON THE ARRIVAL OF WHAT
INCREASINGLY APPEARS TO BE THE COLDEST AIRMASS OF THE SEASON AS A
PIEICE OF THE POLAR VORTEX BREAKS OFF AND AMPLIFIES THE UPPER
TROUGH OVER THE EASTERN PART OF THE COUNTRY.
WARMEST DAY OF THE PERIOD WILL BE SATURDAY AS SOUTHERLY FLOW AHEAD
OF A COLD FRONT ENABLES TEMPS TO RISE INTO THE 40S ACROSS THE
FORECAST AREA. LOW PRESSURE WILL TRACK THROUGH THE GREAT LAKES
SATURDAY NIGHT AND BRING THE COLD FRONT THROUGH CENTRAL INDIANA BY
EARLY SUNDAY. THE FRONT WILL USHER IN THE INITIAL SHOT OF COLDER
AIR...AS TEMPS ARE LIKELY TO FALL BACK INTO THE 20S AND LOWER 30S.
PASSAGE OF THE FRONT LOOKS TO BE DRY AS DEEPER MOISTURE IS FOCUSED
CLOSER TO THE LOW ACROSS THE GREAT LAKES. ARCTIC FRONT SET TO DIVE
INTO THE REGION ON MONDAY...USHERING IN MUCH COLDER AIR AS 850MB
TEMPS NOSEDIVE. ANTICIPATE SNOW SHOWERS TO ACCOMPANY THE FRONTAL
PASSAGE AND AS WIND FLOW ALIGNS TO THE NORTHWEST IN ITS WAKE...
LIKELY TO SEE SOME IMPACTS FROM LAKE ENHANCEMENT SNOW SHOWERS
THROUGH MONDAY NIGHT.
THE MUCH GREATER IMPACT WITH THE FRONTAL PASSAGE WILL BE TO
TEMPERATURES AS 850MB TEMPS ON BOTH THE ECMWF AND OP GFS FALL INTO
THE -23 TO -21C RANGE BY TUESDAY. IF THESE NUMBERS EVEN COME CLOSE
TO VERIFYING...HIGH TEMPS ON TUESDAY ARE LIKELY TO STRUGGLE INTO
THE 10-15 DEGREE RANGE AND PROVIDE CENTRAL INDIANA WITH THE
COLDEST AIR OF THE SEASON TO DATE. KNOWING HOW MODELS THIS FAR OUT
TEND TO UNDEROD THE DEPTH OF ARCTIC COLD AND WITH GROWING
CONFIDENCE IN THE INTENSITY OF THE COLD AIRMASS...HAVE CHOSEN TO
UNDERCUT ALLBLEND TEMPS BY 3 TO 4 DEGREES FOR BOTH MONDAY AND
TUESDAY. LOWS MAY BE DOWN NEAR ZERO BY TUESDAY NIGHT.
&&
.AVIATION /DISCUSSION FOR 151800Z TAF ISSUANCE/...
ISSUED AT 1153 AM EST TUE JAN 15 2013
VFR CONDITIONS ANTICIPATED THROUGHOUT THE FORECAST.
MID AND HIGH LEVEL CLOUD COVERAGE WILL STEADILY INCREASE ACROSS
CENTRAL INDIANA THIS AFTERNOON AS LOW PRESSURE MOVES OUT OF THE
GULF COAST REGION AND INTO THE LOWER TENNESSEE VALLEY THIS
EVENING. LARGE AREA OF CEILINGS AROUND 10KFT OVER THE OZARKS
QUICKLY EXPANDING NORTHEAST AND SHOULD ENVELOP THE TERMINALS BY
MID AFTERNOON. MOISTURE PROFILE DEEPENS THIS EVENING WITH CEILINGS
LIKELY TO FALL TO 6-8KFT FOR SEVERAL HOURS...ESPECIALLY AT KBMG/
KHUF/KIND. BOUNDARY LAYER HOWEVER REMAINS DRY WITH A PERSISTENT
LOW LEVEL FLOW FROM THE NORTHEAST.
AS THE LOW PRESSURE SHIFTS INTO THE SOUTHERN APPALACHIANS LATE
TONIGHT...MOISTURE ALOFT WILL ALSO BEGIN TO DEPART OFF TO THE EAST
AND CEILINGS ARE EXPECTED TO LIFT AND SCATTER IN THE HOURS
APPROACHING DAYBREAK. HIGH PRESSURE RIDGE THEN BUILDS INTO THE
REGION WEDNESDAY WITH BROAD SUBSIDENCE AND WILL SEE SKIES BECOME
MOSTLY CLEAR. LIGHT AND VARIABLE WINDS LATE TONIGHT WILL SHIFT TO
W/SW AND INCREASE TO NEAR 10KTS WEDNESDAY.
&&
.IND WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
SYNOPSIS...CP
NEAR TERM...CP
SHORT TERM...CP
LONG TERM....RYAN
AVIATION...RYAN
AREA FORECAST DISCUSSION
NWS INDIANAPOLIS IN
215 PM EST TUE JAN 15 2013
.UPDATE...
THE SYNOPSIS...NEAR TERM AND SHORT TERM SECTIONS HAVE BEEN UPDATED BELOW
&&
.SYNOPSIS...
ISSUED AT 212 PM EST TUE JAN 15 2013
QUIET WEATHER CAN BE EXPECTED UNDER HIGH PRESSURE THROUGH THE END
OF THE WEEK WITH TEMPERATURES NEAR NORMAL FOR THIS TIME OF YEAR.
COULD SEE A BRIEF WARM UP SATURDAY INTO THE 40S BEFORE
TEMPERATURES DROP BACK TO NORMAL SUNDAY AND THEN GET VERY COLD TO
START OUT THE WEEK. A CLIPPER SYSTEM WILL MOVE THROUGH SUNDAY
NIGHT THROUGH MONDAY NIGHT BRINGING CHANCES FOR SNOW.
&&
.NEAR TERM /TONIGHT/...
ISSUED AT 212 PM EST TUE JAN 15 2013
SKIES SHOULD START OUT MOSTLY CLOUDY WITH A LOW PRESSURE SYSTEM
MOVING NORTHEAST OUT OF THE GULF AND THROUGH THE SOUTHEASTERN U.S. A
BIT OF MODEL DISAGREEMENT OVER HOW FAR NORTH PRECIPITATION
ASSOCIATED WITH THIS SYSTEM WILL GET DESPITE SIMILAR POSITIONS AND
STRENGTH FOR THE LOW PRESSURE CENTER. THE RAP AND GEM WERE THE
FURTHEST NORTH AND BRING THE PRECIP INTO THE FAR SOUTHEASTERN
COUNTIES. THE GFS KEEPS THE PRECIP WELL TO THE SOUTH...WHILE THE NAM
AND 0Z ECMWF JUST CLIP THE FAR SOUTHEAST WITH A HUNDREDTH OF QPF.
WITH THE VARIETY OF SOLUTIONS SHOULD CARRY A LOW CHANCE POP IN THE
FAR SOUTHEAST WITH DRY WEATHER BUT MOSTLY CLOUDY SKIES ELSEWHERE.
WENT WITH LOWS A DEGREE OR TWO BELOW GUIDANCE WITH EXPECTED COLD
ADVECTION.
&&
.SHORT TERM /WEDNESDAY THROUGH FRIDAY/...
ISSUED AT 212 PM EST TUE JAN 15 2013
HIGH PRESSURE WILL REMAIN OVER THE AREA THROUGH THE SHORT TERM. A
LOW PRESSURE SYSTEM MOVING ACROSS THE HUDSON BAY WILL DRAG A COLD
FRONT ACROSS THE GREAT LAKES WEDNESDAY AND WEDNESDAY NIGHT...BUT IT LOOKS
LIKE ALL THE FORCING ASSOCIATED WITH IT WILL STAY WELL NORTH OF THE
AREA. ANOTHER SOUTHERN LOW PRESSURE SYSTEM WHICH WILL MOVE ACROSS
THE SOUTHEAST U.S. DURING THE SAME TIME APPEARS TO BE TOO FAR SOUTH
TO IMPACT POPS HERE. GUIDANCE IS IN GOOD AGREEMENT AND WILL USE AN
AVERAGE WHICH RESULTS IN NEAR NORMAL TEMPERATURES AND DRY WEATHER.
&&
.LONG TERM /FRIDAY THROUGH MONDAY/...
ISSUED AT 343 AM EST TUE JAN 15 2013
MAIN FOCUS ON THE EXTENDED WILL BE ON LATE WEEKEND ARCTIC AIR
INVASION.
THE 00Z GFS HAS CONTINUED TO BE MORE AGGRESSIVE IN BRINGING WESTERN
LOBE OF THE POLAR VORTEX SOUTHEAST ACROSS THE FORECAST AREA LATE IN
THE WEEKEND COMPARED TO THE OPERATIONAL 00Z ECMWF. USUALLY WITH
DIFFERENCES IN THE DETERMINISTIC MODELS...BETTER TO SIDE WITH THE
ENSEMBLE MEANS AS A COMPROMISE AND ACCEPT REGIONAL INITIALIZATION
TEMPERATURES WHICH START OFF ABOVE NORMAL WITH LOW LEVEL SOUTHWEST
FLOW AND ZONAL FLOW ALOFT. HOWEVER...ARCTIC FRONT DROPS SOUTH ACROSS
THE FORECAST AREA ON SATURDAY NIGHT BRINGING IN SLIGHTLY BELOW
NORMAL TEMPERATURES BY SUNDAY AND MUCH COLDER TEMPERATURES BY
MONDAY. BY TUESDAY...HIGHS WILL MOSTLY ONLY BE IN THE TEENS WITH
OVERNIGHT LOWS IN THE SINGLE DIGITS BY MONDAY NIGHT. POLAR VORTEX
LOBE COULD ALSO BRING A FEW SNOW SHOWERS TO MAINLY THE NORTHERN
FORECAST AREA BY SUNDAY NIGHT.
&&
.AVIATION /DISCUSSION FOR 151800Z TAF ISSUANCE/...
ISSUED AT 1153 AM EST TUE JAN 15 2013
VFR CONDITIONS ANTICIPATED THROUGHOUT THE FORECAST.
MID AND HIGH LEVEL CLOUD COVERAGE WILL STEADILY INCREASE ACROSS
CENTRAL INDIANA THIS AFTERNOON AS LOW PRESSURE MOVES OUT OF THE
GULF COAST REGION AND INTO THE LOWER TENNESSEE VALLEY THIS
EVENING. LARGE AREA OF CEILINGS AROUND 10KFT OVER THE OZARKS
QUICKLY EXPANDING NORTHEAST AND SHOULD ENVELOP THE TERMINALS BY
MID AFTERNOON. MOISTURE PROFILE DEEPENS THIS EVENING WITH CEILINGS
LIKELY TO FALL TO 6-8KFT FOR SEVERAL HOURS...ESPECIALLY AT KBMG/
KHUF/KIND. BOUNDARY LAYER HOWEVER REMAINS DRY WITH A PERSISTENT
LOW LEVEL FLOW FROM THE NORTHEAST.
AS THE LOW PRESSURE SHIFTS INTO THE SOUTHERN APPALACHIANS LATE
TONIGHT...MOISTURE ALOFT WILL ALSO BEGIN TO DEPART OFF TO THE EAST
AND CEILINGS ARE EXPECTED TO LIFT AND SCATTER IN THE HOURS
APPROACHING DAYBREAK. HIGH PRESSURE RIDGE THEN BUILDS INTO THE
REGION WEDNESDAY WITH BROAD SUBSIDENCE AND WILL SEE SKIES BECOME
MOSTLY CLEAR. LIGHT AND VARIABLE WINDS LATE TONIGHT WILL SHIFT TO
W/SW AND INCREASE TO NEAR 10KTS WEDNESDAY.
&&
.IND WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...CP
NEAR TERM...CP
SHORT TERM...CP
LONG TERM....MK
AVIATION...RYAN
AREA FORECAST DISCUSSION
NWS TOPEKA KS
315 PM CST TUE JAN 15 2013
.DISCUSSION...
20Z WATER VAPOR SHOWS THE TROUGH AXIS OVERHEAD WITH THE UPPER
FLOW BEGINNING TO SPLIT WITH ENERGY BEING LEFT BEHIND OVER THE
SOUTHERN HIGH PLAINS. AT THE SURFACE...THE RIDGE AXIS STRETCHED
FROM THE TX PANHANDLE UP TO CHICAGO. THERE IS A MAXIMUM IN SURFACE
DEWPOINTS IMMEDIATELY DOWNSTREAM OF THE SNOW PACK IN SOUTHERN NEB.
WITH DAYTIME HEATING STEEPENING UP LOW LEVEL LAPSE RATES WITH
ADDED BOUNDARY LAYER MOISTURE...A CU FIELD HAS FORMED OVER NORTH
CENTRAL KS. WOULD EXPECT THESE CLOUDS TO DIMINISH WITH THE LOSS OF
DAYTIME HEATING AND THE 19Z RAP AND 18Z NAM SEEM TO SUPPORT THIS
IDEA...SO THINK SKIES SHOULD BECOME MOSTLY CLEAR OVERNIGHT.
FOR TONIGHT AND WEDNESDAY...THE FORECAST AREA IS EXPECTED TO BE
BETWEEN THE SPLITTING PATTERN WITH A CLOSED LOW REMAINING OVER THE
SOUTHERN PLAINS AND STRONG NORTHWEST FLOW REMAINING NORTH OVER THE
DAKOTAS AND UPPER MIDWEST. THEREFORE THERE IS EXPECTED TO BE LITTLE
OR NOW LARGE SCALE FORCING AFFECTING THE FORECAST AREA. WITH THIS
AND A DRY AIRMASS TO START OUT WITH...THE FORECAST REMAINS DRY.
THERE WILL BE A TROUGH AXIS/WIND SHIFT MOVE THROUGH THE AREA ON
WEDNESDAY. MODELS DO NOT SHOW ANY COLD AIR BEHIND THIS BOUNDARY AND
IN FACT HAVE WARM AIR ADVECTING IN FROM THE WEST WITH A DOWNSLOPE
WIND. THEREFORE HAVE CONTINUED WITH HIGHS GENERALLY AROUND 50. THERE
IS INDICATIONS FROM THE NAM AND GFS OF SOME SATURATED AIR BEHIND THE
FRONT WHICH COULD BE HELPED BY MELTING SNOW IN NEB...SO THINK SKIES
COULD BECOME PARTLY CLOUDY AS WINDS SHIFT TO THE WEST AND NORTHWEST.
THE PRESSURE GRADIENT SHOULD INCREASE OVERNIGHT AS THE SURFACE
TROUGH APPROACHES THE AREA. THIS SHOULD CAUSE WINDS TO GRADUALLY
INCREASE OVERNIGHT HELPING TO KEEP MIN TEMPS SEVERAL DEGREES WARMER
THAN THIS MORNING AND HAVE MIN TEMPS IN THE UPPER TEENS.
WOLTERS
CLEAR SKIES TO BE THE RULE THROUGH EARLY NEXT WEEK WITH NORTHWEST
FLOW ALOFT KEEPING MOISTURE RETURN IN CHECK AND MEAGER FORCING
MECHANISMS FOR CLOUDS LET ALONE PRECIPITATION. WEAK SURFACE HIGH
BUILDS IN THURSDAY WITH ACTUALLY A BIT OF WARMING AROUND
850MB...BUT THE LIMITED MIXING SHOULD KEEP HIGHS A FEW DEGREES
COOLER THAN WEDNESDAY. FRIDAY STILL LOOKING THE BE THE WARMEST DAY
WITH WEST TO SOUTHWEST WINDS DEVELOPING AHEAD OF A WAVE IN THE GREAT
LAKES. SATURDAY WILL SEE THE FIRST OF TWO COLD FRONTS MOVE IN DURING
THE DAY. MID TO LATE DAY COLD AIR ADVECTION SHOULD KEEP HIGHS IN THE
40S...WITH A MORE POTENT SHOT COMING IN THE SUNDAY NIGHT INTO MONDAY
TIME FRAME. THERE HAS BEEN SOME VACILLATION IN THE MODELS WITH HOW
FAR SOUTHWEST THE COLD AIR WILL REACH AND SPECIFIC TIMING OF THE
COLD AIR REMAINS UNCERTAIN. ALSO...THERE IS GOOD AGREEMENT WITH THE
UPPER PATTERN BREAKING DOWN TO A MORE ZONAL CHARACTER AS THE EASTERN
PACIFIC RIDGE BREAKS DOWN LEADING TO THE COLDEST AIR/S RESIDENCE
TIME IN THE CENTRAL PLAINS LIMITED. MONDAYS MAXES IN THE UPPER TEENS
TO MID 20S SEEM REASONABLE AT THIS POINT WITH MODIFICATION FOR
TUESDAY.
65
&&
.AVIATION...
DRY AIR AND NO FORCING WILL LEAD TO VFR CONDITIONS PREVAILING
THROUGH TONIGHT. A WEAK WIND SHIFT SHOULD MOVE THROUGH THE TERMINALS
BY EARLY AFTERNOON WEDNESDAY. MODELS ARE SUGGESTING A BRIEF PERIOD
OF CIGS BETWEEN 2 AND 3 KFT JUST BEHIND THE FRONT. HAVE NOT ACTED ON
THIS SINCE IT IS NEAR THE END OF THE FORECAST PERIOD...AND THIS
SHOULD ALLOW LATER SHIFTS TO LOOK AT FUTURE GUIDANCE TO SEE IF
MODELS ARE PERSISTENT WITH THE CIGS.
WOLTERS
&&
.TOP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS GOODLAND KS
212 PM MST TUE JAN 15 2013
.SHORT TERM...(THIS AFTERNOON THROUGH WEDNESDAY)
ISSUED AT 212 PM MST TUE JAN 15 2013
LATEST WV IMAGERY AND RUC H5 ANALYSIS SHOWS LONGWAVE TROUGH EXTENDING
FROM THE GREAT LAKES ACROSS CENTRAL KANSAS INTO NORTHERN MEXICO. CWA
IS CURRENTLY ON SUBSIDENT SIDE OF TROUGH AXIS UNDER SHORTWAVE
RIDGING. A WEAK SHORTWAVE TROUGH OVER MONTANA IS CURRENTLY MOVING
THROUGH N/NW FLOW ALONG THE BACK SIDE OF THE TROUGH.
THIS FEATURE IS EXPECTED TO SPLIT WITH A WEAK PIECE OF ENERGY MOVING
SOUTH ACROSS EASTERN COLORADO TONIGHT. WITH MAIN H3 JET AXIS WELL
NORTH OF THE CWA...I AM ONLY ANTICIPATING WEAK FORCING. MODEL
SOUNDINGS INDICATE A SATURATED LEVEL BETWEEN 800-600MB. WITH WEAK
FORCING IN THE WEST...AND VERY LITTLE IN THE WAY OF QPF SHOWN BY
AVAILABLE GUIDANCE I LIMITED SLIGHT CHANCE POPS TO WESTERN CWA THIS
EVENING AND OVERNIGHT...AND SCATTERED FLURRIES ELSEWHERE. EVEN IN
THE WEST WHERE MEASURABLE SNOW IS POSSIBLE I WOULD ONLY ANTICIPATE
A FEW TENTHS OF AN INCH WITH THIS SYSTEM.
SUBSIDENCE ALONG AND A MUCH DRIER AIR MASS WILL SPREAD EAST
WEDNESDAY WITH W/NW FLOW DEVELOPING. AIR MASS HAS ALREADY MODIFIED
WITH SHORTWAVE RIDGING THIS AFTERNOON AND SHOULD CONTINUE TO MODIFY
WED WITH HIGHS IN THE 40S/NEAR 50. THE SNOW PACK IN THE WEST AND NE
WILL STILL KEEP HIGHS SLIGHTLY COOLER...HOWEVER WITH WESTERLY WINDS
WE SHOULD STILL SEE HIGHS AROUND 40F AT THE COLDEST. A CONCERN FOR
WED WILL BE WINDS...WITH BREEZY TO WINDY CONDITIONS ANTICIPATED. I
AM LESS CONFIDENT HOW WINDY IT WILL BE WITH LIMITED MIXING HEIGHTS
BASED ON SOUNDING ANALYSIS. IF WE MIX MUCH HIGHER THAN CURRENT
SOUNDINGS SUGGEST...THEN WE COULD SEE ADVISORY CRITERIA MET...
ESPECIALLY IF WE USE THE NAM WINDS ALOFT. FOR NOW...I LIMITED WINDS
TO JUST UNDER ADVISORY CRITERIA WED AFTERNOON.
.LONG TERM...(WEDNESDAY NIGHT THROUGH TUESDAY)
ISSUED AT 212 PM MST TUE JAN 15 2013
FORECAST PROBLEMS WILL BE THE AMOUNT OF WARMUP BEFORE THE NEXT VERY
COLD AIR MASS ARRIVES AND HOW COLD WILL THAT AIR MASS ALONG WITH
WHEN IT ARRIVES. SATELLITE SHOWING AN AMPLIFIED FLOW STARTING WITH
A BROAD...DEEP AND COMPLICATED UPPER TROUGH OVER THE WESTERN HALF OF
THE PACIFIC WHICH IS MAINTAINING/AMPLIFYING AN UPPER RIDGE NEAR THE
WEST COAST OF NORTH AMERICA. THIS TRANSITIONS TO A TROUGH OVER THE
CENTER OF THE COUNTRY WHICH HAS/CONTINUES TO SPLIT. WARMER AIR MASS
STARTING TO WORK ITS WAY INTO THE REGION.
AT JET LEVEL...THE MODELS INITIALIZED FINE WITH THE ECMWF SLIGHTLY
WORSE THAN THE OTHERS. SATELLITE AND UPPER AIR ANALYSIS SHOW THE
MODELS HAVE INITIALIZED WELL AT MID LEVELS. HOWEVER WOULD HAVE TO
SLIGHTLY FAVOR THE UKMET/CANADIAN OVER THE NAM/ECMWF. AT THE
SURFACE THE SREF WAS DOING A LITTLE BETTER THAN THE ECMWF. THE UKMET
WAS DOING A LITTLE BETTER THAN THE ECMWF AND GFS ON THE LOW LEVEL
THERMAL FIELD.
WEDNESDAY NIGHT/THURSDAY...MAIN STORM TRACK REMAINS WELL NORTH OF
THE AREA AND UNDER SUBSIDENCE FROM THE JET. FLOW ALOFT IS MORE
NORTHWEST WITH LITTLE TO NO CLOUD COVER EXPECTED AT THIS TIME.
WINDS MAY DROP OFF LATE IN THE NIGHT MAINLY IN THE WEST. SURFACE
RIDGE MOVES THROUGH EARLY IN THE DAY ON THURSDAY WITH WINDS SHIFTING
MORE TOWARD THE SOUTH IN THE AFTERNOON. ADJUSTED TEMPERATURES UP A
LITTLE.
THURSDAY NIGHT/FRIDAY...STORM TRACK STILL NORTH OF THE AREA WITH
WEST TO NORTHWEST FLOW ALOFT. THERE MAY BE A LITTLE MORE CLOUD
COVER DURING THE NIGHT AS A WEAK SYSTEM MOVES THROUGH IN THE FLOW
BUT AGAIN LITTLE TO NO CLOUD COVER EXPECTED. DOWNSLOPE COMPONENT IS
MUCH BETTER ON THE WINDS AND ALL MODELS ARE SIMILAR IN THEIR INCREASE
IN THE 850 MB TEMPERATURES. ALSO WOULD EXPECT THE WARM AIR ADVECTION
AND DOWNSLOPE WILL BE BETTER THAN DEPICTED SINCE THIS WILL BE AHEAD
OF THE INITIAL PUSH OF COLDER THAT WILL COME IN ON SATURDAY. SO FELT
COMFORTABLE IN WARMING UP MAXES FROM THE CURRENT PACKAGE. IT IS
POSSIBLE THAT ADDITIONAL RAISING OF THE MAXES WILL BE POSSIBLE.
FRIDAY NIGHT THROUGH TUESDAY...BIG CHANGE IN THE WEATHER...TO MUCH
COLDER TEMPERATURES THIS WEEKEND INTO THE BEGINNING OF NEXT WEEK...
STILL LOOKS ON TRACK. THERE ARE STILL DIFFERENCES IN THE MODELS BUT
THEY ARE MUCH CLOSER THAN YESTERDAY WHICH INCREASES CONFIDENCE ON
THE MAGNITUDE AND ESPECIALLY THE TIMING. SATURDAY LOOKS TO BE VERY
TRICKY. THE INITIAL PUSH IS COMING IN A LITTLE FASTER AND LOOKS
LIKE IT MAY ARRIVE LATE MORNING INTO EARLY AFTERNOON ESPECIALLY IN
THE NORTHEAST HALF OF THE AREA. SO THERE LOOKS TO BE A GOOD GRADIENT
ACROSS MY AREA WHICH WILL NEED TO BE RESOLVED AS WE GET MUCH CLOSER
TO THE DAY. AT THIS TIME TOOK WHAT WAS GIVEN TO ME BY THE CRH_INIT
AND NUDGED DOWN A LITTLE AS I BLENDED WITH NEIGHBORS.
FIRST PUSH OF THE COLD AIR LOOKS TO BE WELL ENTRENCHED BY 12Z
SUNDAY. MODELS WANT TO SCOUR OUT THE COLD AIR DURING THE DAY AS WINDS
SHIFT TO THE WEST BEFORE THE COLDEST AIR ARRIVES SUNDAY NIGHT. NOT
ENTIRELY SOLD ON THAT. SO AFTER COLLABORATION WITH NEIGHBORS DID
LOWER MAXES FROM WHAT WAS GIVEN BY THE INIT. VERY COLD AIR TO
ARRIVE SUNDAY NIGHT INTO MONDAY PER MODEL CONSENSUS. AFTER
COLLABORATION FELT VERY COMFORTABLE IN LOWERING MAXES SIGNIFICANTLY.
WHEN THE COLD AIR COMES IN SUNDAY NIGHT AND MONDAY FLURRIES WILL BE
POSSIBLE. THEN MODELS WANT TO REALLY SCOUR OUT THE COLD AIR ON
TUESDAY AND AGAIN NOT SOLD ON THAT. HOWEVER...THE INIT GAVE ME COOLER
TEMPERATURES THAN WHAT THE MODEL 850 TEMPERATURES SAY. SO AGREED WITH
SURROUNDING OFFICES IN LEAVING THOSE TEMPERATURES ALONE FOR NOW.
THANKS TO ALL FOR THE COLLABORATION.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z WEDNESDAY AFTERNOON)
ISSUED AT 1039 AM MST TUE JAN 15 2013
VFR CONDITIONS WILL PERSIST THROUGH THE NEXT 24 HOURS AT BOTH GLD
AND MCK...WITH A SMALL CHANCE FOR A SHORT PERIOD OF MVFR CEILINGS AT
EITHER SITE. SKIES ARE CLEAR AT THE MOMENT BUT MID-LEVEL CLOUDS WILL
INCREASE LATER THIS AFTERNOON ASSOCIATED WITH AN UPPER DISTURBANCE
THAT WILL MOVE THROUGH BOTH SITES QUICKLY TONIGHT. THERE IS A CHANCE
FOR FLURRIES OR LIGHT SNOW...BUT AM NOT CONFIDENT THAT PRECIPITATION
WILL REACH EITHER TERMINAL. CEILINGS WILL APPROACH MVFR AT
TIMES...WITH SKIES CLEARING BY EARLY TOMORROW MORNING. WINDS OVER
THE PERIOD WILL BEGIN LIGHT OUT OF THE WEST...BECOMING STRONGER
BEHIND THE DISTURBANCE WITH GUSTS UP TO 25KTS OUT OF THE
NORTHWEST.
&&
.GLD WATCHES/WARNINGS/ADVISORIES...
KS...NONE.
CO...NONE.
NE...NONE.
&&
$$
SHORT TERM...DR
LONG TERM...BULLER
AVIATION...JJM
AREA FORECAST DISCUSSION
NWS GOODLAND KS
1149 PM MST MON JAN 14 2013
.SHORT TERM...(THIS AFTERNOON THROUGH TUESDAY)
ISSUED AT 111 PM MST MON JAN 14 2013
CURRENT WV IMAGERY AND RUC H5 ANALYSIS SHOW LARGE TROUGH EXTENDING
FROM CANADA ACROSS THE PLAINS AND SW US TO THE BAJA PENINSULA. MEAN
AXIS IS CURRENTLY UPSTREAM OF CWA ALONG THE CENTRAL ROCKIES WITH
SURFACE TROUGH ALONG FRONT RANGE.
RUC INDICATES AXIS OF H85-H7 FRONTOGENESIS IN PLACE ACROSS EASTERN
COLORADO AND FAR WESTERN KANSAS WHERE LIGHT SNOW HAS BEEN FALLING
FOR MOST OF THE DAY. AS THE UPPER LEVEL TROUGH SHIFTS EAST THIS
EVENING THIS AXIS OF FORCING WILL BEGIN TO WEAKEN AND SHIFT
SOUTH...WITH SNOW COMING TO AN END OVER OUR SW CWA BY 03Z. I
COULD NOT RULE OUT ADDITIONAL SNOW ACCUMULATION AROUND ONE INCH
ALONG AN AXIS FROM STRATTON COLORADO TO BENKELMAN NEBRASKA THROUGH
THIS AFTERNOON WHERE RADAR SHOWS SOME INTENSIFICATION...HOWEVER
MOST LOCATIONS SHOULD SEE LESS THAN ONE HALF INCH TOTAL SNOW
ACCUMULATION FOR THIS EVENT. SUBSIDENCE AND A DRY AIR MASS WILL
BEGIN TO WORK IN OVER THE CWA AFTER MIDNIGHT WITH CLEARING SKIES
FROM THE NORTHWEST OVERNIGHT. THERE WILL BE LITTLE CHANGE IN THE
COLD AIRMASS FROM LAST NIGHT...SO DEPENDING ON HOW QUICKLY
CLOUDS CLEAR WE COULD SEE NEGATIVE TEMPERATURES ONCE AGAIN OVER
PARTS OF THE CWA. FOR NOW I LIMITED COLDEST TEMPS TO THE NORTH AND
WEST WHERE CLOUDS ARE MOST LIKELY TO CLEAR BEFORE SUNRISE.
AIRMASS WILL BEGIN TO MODERATE BY MIDDAY TUESDAY AS LEE TROUGH
DEVELOPS AND WINDS SHIFT TO THE WEST. IT IS A TOUGH CALL ON WHAT
IMPACT LINGERING SNOW PACK WILL HAVE...HOWEVER WE SHOULD SEE
TEMPERATURES IN THE LOW TO MID 30S ACROSS ALL THE CWA...WITH A FEW
LOCATIONS IN THE SOUTH AND EAST POSSIBLY WARMER.
.LONG TERM...(FRIDAY THROUGH TUESDAY)
ISSUED AT 1141 PM MST MON JAN 14 2013
UPPER PATTERN FOR THE PERIOD WILL FEATURE A RIDGE OVER THE WESTERN
CONUS AND A TROUGH OVER THE EAST...LEAVING THE CENTRAL PLAINS
UNDER NORTHWEST FLOW. FRIDAY AND SATURDAY WILL BE DRY WITH
TEMPERATURES SLIGHTLY ABOVE NORMAL. A BACK DOOR COLD FRONT
ASSOCIATED WITH A DISTURBANCE MOVING THROUGH THE FLOW IN THE
NORTHERN PLAINS WILL MOVE INTO THE LOCAL AREA SOMETIME ON
SUNDAY...FOLLOWED BY A REINFORCING SHOT OF COLD AIR ON MONDAY.
SINCE THE UPPER DYNAMICS WILL STAY FAR TO THE NORTHEAST...NO
PRECIPITATION IS EXPECTED WITH EITHER FRONT. MODELS DISAGREE ON
HOW COLD IT WILL GET WITH THE FRONTS...PARTICULARLY ON MONDAY...BUT
THE EXTENDED INITIALIZATION ALGORITHM ESSENTIALLY SPLIT THE
DIFFERENCE WHICH IS AS GOOD AN APPROACH AS ANY AT THIS TIME RANGE.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z TUESDAY NIGHT)
ISSUED AT 954 PM MST MON JAN 14 2013
VFR CONDITIONS WILL CONTINUE AT KGLD AND KMCK FOR THE NEXT 24
HOURS. CLEARING WILL OCCUR AT BOTH SITES BY SUNRISE AND THEN
CLOUDS WILL INCREASE AGAIN TUESDAY EVENING AS THE NEXT DISTURBANCE
COMES THROUGH NORTHERLY FLOW INTO THE AREA. SOME FLURRIES WILL BE
POSSIBLE AT BOTH SITES DURING THE EVENING.
&&
.GLD WATCHES/WARNINGS/ADVISORIES...
KS...NONE.
CO...NONE.
NE...NONE.
&&
$$
SHORT TERM...DR
LONG TERM...024
AVIATION...032
AREA FORECAST DISCUSSION
NWS GOODLAND KS
1020 PM MST MON JAN 14 2013
.SHORT TERM...(THIS AFTERNOON THROUGH TUESDAY)
ISSUED AT 111 PM MST MON JAN 14 2013
CURRENT WV IMAGERY AND RUC H5 ANALYSIS SHOW LARGE TROUGH EXTENDING
FROM CANADA ACROSS THE PLAINS AND SW US TO THE BAJA PENINSULA. MEAN
AXIS IS CURRENTLY UPSTREAM OF CWA ALONG THE CENTRAL ROCKIES WITH
SURFACE TROUGH ALONG FRONT RANGE.
RUC INDICATES AXIS OF H85-H7 FRONTOGENESIS IN PLACE ACROSS EASTERN
COLORADO AND FAR WESTERN KANSAS WHERE LIGHT SNOW HAS BEEN FALLING
FOR MOST OF THE DAY. AS THE UPPER LEVEL TROUGH SHIFTS EAST THIS
EVENING THIS AXIS OF FORCING WILL BEGIN TO WEAKEN AND SHIFT
SOUTH...WITH SNOW COMING TO AN END OVER OUR SW CWA BY 03Z. I
COULD NOT RULE OUT ADDITIONAL SNOW ACCUMULATION AROUND ONE INCH
ALONG AN AXIS FROM STRATTON COLORADO TO BENKELMAN NEBRASKA THROUGH
THIS AFTERNOON WHERE RADAR SHOWS SOME INTENSIFICATION...HOWEVER
MOST LOCATIONS SHOULD SEE LESS THAN ONE HALF INCH TOTAL SNOW
ACCUMULATION FOR THIS EVENT. SUBSIDENCE AND A DRY AIR MASS WILL
BEGIN TO WORK IN OVER THE CWA AFTER MIDNIGHT WITH CLEARING SKIES
FROM THE NORTHWEST OVERNIGHT. THERE WILL BE LITTLE CHANGE IN THE
COLD AIRMASS FROM LAST NIGHT...SO DEPENDING ON HOW QUICKLY
CLOUDS CLEAR WE COULD SEE NEGATIVE TEMPERATURES ONCE AGAIN OVER
PARTS OF THE CWA. FOR NOW I LIMITED COLDEST TEMPS TO THE NORTH AND
WEST WHERE CLOUDS ARE MOST LIKELY TO CLEAR BEFORE SUNRISE.
AIRMASS WILL BEGIN TO MODERATE BY MIDDAY TUESDAY AS LEE TROUGH
DEVELOPS AND WINDS SHIFT TO THE WEST. IT IS A TOUGH CALL ON WHAT
IMPACT LINGERING SNOW PACK WILL HAVE...HOWEVER WE SHOULD SEE
TEMPERATURES IN THE LOW TO MID 30S ACROSS ALL THE CWA...WITH A FEW
LOCATIONS IN THE SOUTH AND EAST POSSIBLY WARMER.
.LONG TERM...(TUESDAY NIGHT THROUGH MONDAY)
ISSUED AT 233 PM MST MON JAN 14 2013
FORECAST PROBLEMS WILL BE AMOUNT OF WARMUP DURING THE EARLY PORTION
OF THIS PERIOD FOLLOWED BY HOW MUCH TO COOL IT DOWN AT THE END OF
THE PERIOD. SATELLITE SHOWING AN AMPLIFIED FLOW STARTING WITH A
BROAD...DEEP AND COMPLICATED UPPER TROUGH OVER THE WESTERN HALF OF
THE PACIFIC WHICH IS MAINTAINING/AMPLIFYING AN UPPER RIDGE NEAR THE
WEST COAST OF NORTH AMERICA. THIS TRANSITIONS TO A TROUGH OVER THE
CENTER OF THE COUNTRY WHICH HAS/CONTINUES TO SPLIT. COLD AIR REMAINS
OVER THE AREA AND UPSTREAM AT THIS TIME.
MODELS INITIALIZED FINE AT JET LEVEL. HOWEVER...THEY WERE A LITTLE
UNDERDONE ON THE SPEEDS BEHIND THE UPPER TROUGH OVER THE COUNTRY.
THE GFS WAS DOING A LITTLE BETTER THAN THE CANADIAN AND NAM. MODELS
INITIALIZED FINE AT MID LEVELS WITH THE ECMWF AND UKMET DOING A
LITTLE BETTER THAN THE GFS AND CANADIAN. THE ECMWF WAS DOING THE
BEST AT THE SURFACE. THE ECMWF WAS DOING A LITTLE BETTER THAN THE
GFS...UKMET AND CANADIAN ON THE LOW LEVEL THERMAL FIELD.
TUESDAY NIGHT/WEDNESDAY...LEFT FRONT QUADRANT OF THE JET MOVES
ACROSS DURING THE NIGHT. UPPER TROUGH WILL HAVE MOVED EAST OF THE
AREA BY THE BEGINNING OF THIS PERIOD. IN ADDITION TO THE LIFT FROM
THE JET...MOISTURE INCREASES THROUGH MID LEVELS ON THE WEST SIDE OF
THE TROUGH. THERE IS SOME MODERATE FRONTOGENESIS AS WELL. LAPSE
RATES ARE NOT THAT GREAT. HOWEVER WITH THE COLD AIR IN PLACE AND THE
MODELS SHOWING DEEP ENOUGH MOISTURE...WILL INSERT FLURRIES INTO
THE NORTHWEST HALF SINCE THE SYNOPTIC LIFT IS NOT THAT GREAT BUT
MESOSCALE FORCING IS PRETTY GOOD. WHATEVER FALLS SHOULD BE DONE BY
06Z.
AFTER THE FLURRIES END...SUBSIDENCE INCREASE BEHIND JET AND UPPER
TROUGH. SO WINDS COULD BECOME BREEZY FROM A DOWNSLOPE DIRECTION FOR
A SHORT PERIOD OF TIME. THIS SHOULD MAKE THE MINS WARMER AND DID
WARM THEM SOME BUT MAYBE NOT ENOUGH. PLENTY OF SUN AND DOWNSLOPE
WINDS SHOULD MAKE FOR A MUCH WARMER DAY THAN WE HAVE BEEN HAVING
LATELY. IN GENERAL...MAXES SHOULD RANGE FROM THE MIDDLE 40S TO NEAR
50 DEGREES.
WEDNESDAY NIGHT/THURSDAY...DOWNSLOPE WINDS SHOULD KEEP MINS WARMER
AGAIN. WILL HAVE PLENTY OF SUN BUT NOT AS FAVORABLE OF A WIND FIELD.
NEW GUIDANCE INDICATES HIGH TEMPERATURES SIMILAR TO WEDNESDAYS AND
DID NOT CHANGE MUCH.
THURSDAY NIGHT THROUGH MONDAY...CURRENT AMPLIFIED PATTERN FLATTENS
OUT A LITTLE BIT EARLY IN THE PERIOD BEFORE BECOMING VERY AMPLIFIED
BY THE END OF THE PERIOD ONCE AGAIN. THROUGH FRIDAY SHOULD MAINTAIN
HIGH TEMPERATURES VERY SIMILAR TO WHAT THEY WERE ON WEDNESDAY AND
THURSDAY. THEN A BIG CHANGE IS GOING TO OCCUR IN TEMPERATURE BUT
WITH UNCERTAINTY IN TIMING AND MAGNITUDE OF THIS TEMPERATURE.
GIVEN WHAT THE PATTERN IS...HAVING A MUCH COLDER AIR MASS INTRUDE
INTO THE REGION IS PRETTY MUCH A GIVEN BUT THE MODELS DISAGREE ON
HOW FAST THEY WHAT TO DO IT. THE GFS AND CANADIAN BRING IN THE
COOLER AIR FASTER WHICH IS FROM LATE SATURDAY AFTERNOON INTO THE
NIGHT. THE 00Z AND 12Z ECMWF PRETTY MUCH KEEP THE COLDER AIR OUT
DURING THE DAY ON SATURDAY. HOWEVER...THE 12Z ECMWF IS MUCH QUICKER
THAN THE OLD RUN IN BRINGING THE COLDER AIR ON SATURDAY NIGHT AND
SUNDAY WHICH A BIG DIFFERENCE ON SUNDAY MAXES. MODELS IN BETTER
AGREEMENT AND MUCH BETTER THAN EARLIER IN BRINGING IN AN ABSOLUTELY
FRIGID AIR MASS SUNDAY NIGHT INTO MONDAY.
THROUGH SATURDAY NIGHT LEFT IN WHAT THE CRH_INIT GAVE ME ALTHOUGH IT
IS POSSIBLE THAT SATURDAY AND SATURDAY NIGHT TEMPERATURES COULD BE
COLDER. FELT PER THE AMPLIFIED PATTERN MAKING THE AREA SUSCEPTIBLE
TO HAVING MUCH COLDER AIR BROUGHT IN...SIGNIFICANT SNOW FIELD OVER
THE NORTH CENTRAL PORTION OF THE COUNTRY...AND MORE MODEL SUPPORT FOR
A SOONER ARRIVING COLD AIR MASS WHICH IS NOT UNCOMMON WITH THIS
MAGNITUDE OF COLD AIR...ADJUSTED THE TEMPERATURES...ESPECIALLY THE
MAXES FOR SUNDAY AND MONDAY...DOWN FROM THE INIT. CONSIDERING THE
AIR MASS WE HAVE HAD IN PLACE FOR THE LAST FEW DAYS AND WHAT THE
MODELS ARE SHOWING...THESE TEMPERATURES WILL PROBABLY NOT BE COLD
ENOUGH...BUT STARTED THE TREND DOWN.
IN REGARDS TO THE PRECIPITATION...LEFT WHAT THE CRH_INIT GAVE ME
WHICH HAS IT DRY DURING THE ENTIRE PERIOD. ALTHOUGH WOULD NOT BE
SURPRISED TO SEE SOME FLURRIES WHEN THE COLD AIR MASS BEGINS TO
ENTER THE AREA.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z TUESDAY NIGHT)
ISSUED AT 954 PM MST MON JAN 14 2013
VFR CONDTIIONS WILL CONTINUE AT KGLD AND KMCK FOR THE NEXT 24
HOURS. CLEARING WILL OCCUR AT BOTH SITES BY SUNRISE AND THEN
CLOUDS WILL INCREASE AGAIN TUESDAY EVENING AS THE NEXT DISTURBANCE
COMES THROUGH NORTHERLY FLOW INTO THE AREA. SOME FLURRIES WILL BE
POSSIBLE AT BOTH SITES DURING THE EVENING.
&&
.GLD WATCHES/WARNINGS/ADVISORIES...
KS...NONE.
CO...NONE.
NE...NONE.
&&
$$
SHORT TERM...DR
LONG TERM...BULLER
AVIATION...032
AREA FORECAST DISCUSSION
NWS GAYLORD MI
108 PM EST TUE JAN 15 2013
.SYNOPSIS...
ISSUED AT 346 AM EST TUE JAN 15 2013
SEVERAL AREAS OF LOW PRESSURE AND COLD FRONTS WILL CROSS NORTHERN
MICHIGAN OVER THE NEXT SEVERAL DAYS. THIS WILL PRODUCE PERIODS OF
LAKE EFFECT AND LAKE ENHANCED SNOW SHOWERS...WHICH WILL PRIMARILY
AFFECT EASTERN UPPER AND NORTHWEST LOWER MICHIGAN.
&&
.UPDATE...
ISSUED AT 1257 PM EST TUE JAN 15 2013
CURRENT FORECAST IN GOOD SHAPE WITH CLOUDS DEVELOPING CLOSER TO
LAKE MICHIGAN AND A GOOD AMOUNT OF SUNSHINE INLAND. STILL THINK A
FEW FLURRIES OR LIGHT SNOW SHOWERS ARE LIKELY CLOSER TO THE
LAKE MICHIGAN SHORELINE THIS AFTERNOON...DESPITE ONLY MARGINAL
MOISTURE. ALSO MADE A FEW SMALL ADJUSTMENTS TO TEMPERATURES BASED
ON LATEST OBSERVATIONS.
OTHERWISE...FEW CHANGES TO CURRENT FORECAST FOR THE AFTERNOON
HOURS.
UPDATE ISSUED AT 935 AM EST TUE JAN 15 2013
STRATO-CU HAS LARGELY ERODED THIS MORNING AS DEEP DRY AIR ABOVE
850MB MIXES OUT LOW LEVEL MOISTURE. STILL SEEING AN AREA OF LOW
LEVEL MOISTURE HUGGING THE LAKE MICHIGAN SHORELINE FROM FRANKFORT
SOUTHWARD. WILL LARGELY DISREGARD THE "MOIST" NAM TODAY...WHICH
IS MUCH TOO PESSIMISTIC WITH WIDESPREAD CLOUDINESS ACROSS
NORTHERN MICHIGAN THIS AFTERNOON. COMBO OF LINGERING LOW LEVEL
MOISTURE ALONG THE COASTLINE AND A FEW UPSTREAM PATCHES OF MID
CLOUD OVER WISCONSIN MAY INTERACT WITH STILL PLENTIFUL OVERLAKE
INSTABILITY TO PRODUCE A FEW AFTN FLURRIES CLOSER TO THE LAKE
MICHIGAN COAST. INLAND AREAS SHOULD SEE A GOOD AMOUNT OF SUNSHINE.
CURRENT TEMP FORECAST LOOKS GOOD AND WILL MAKE ONLY SOME MINOR
CHANGES BASED ON CURRENT OBSERVATIONS.
UPDATE ISSUED AT 639 AM EST TUE JAN 15 2013
BIG UPDATES EARLY THIS MORNING...AS THE STRATO CU OFF THE LAKES
HAS RAPIDLY ERODED...LEAVING CLEARING SKIES MOST AREAS...WITH ONLY
SOME SCATTERED FLURRIES. WITH NO DISCERNIBLE MID LEVEL CLOUD
UPSTREAM...OUTSIDE OF A SMALL AREAS IN NORTH CENTRAL
WISCONSIN...WILL DISREGARD NAM/GFS TRAPPED IN SHALLOW STRATO CU
MOSTLY CLOUDY SKY FOR THE DAY. RATHER...WILL OPT TO KEEP SKIES ON
THE CLEARER SIDE FOR THE DAY. THIS AGREED UPON BY LATEST RUC DATA.
AS WINDS INCREASE TONIGHT...MAYBE SOME ADDITIONAL MOISTURE FLUX
OFF THE LAKES...BUT EVEN HERE...DATA SUGGESTS THAT THE ATMOSPHERE
DRIES OUT LATE...PRIOR TO NEXT UPSTREAM CLIPPER/COLD FRONT SET FOR
WEDNESDAY.
&&
.SHORT TERM...(TODAY THROUGH TONIGHT)
ISSUED AT 346 AM EST TUE JAN 15 2013
EARLY MORNING REGIONAL ANALYSIS SHOWS HIGH PRESSURE STRETCHED OUT
ACROSS THE WESTERN LAKES ON FRONT SIDE OF POSITIVELY TILTED DEEP MID
LEVEL TROUGH AXIS EXTENDING FROM HUDSON BAY DOWN TO NEAR THE FOUR
CORNERS. LIGHT WSW FLOW CONTINUES TO ROTATE AROUND NORTH EDGE OF
SURFACE RIDGE AXIS ACROSS THE NORTHERN LAKES. THIS...COMBINED WITH
MORE THAN SUFFICIENT DELTA T/S (RAP ANALYSIS SHOWS H85 TEMPS IN THE
NEGATIVE MID TEENS) AND SLIGHT UPTICK IN LOW LEVEL MOISTURE...HAS
KICKED OFF GENERALLY LIGHT LAKE INDUCED SNOWS ACROSS NORTHWEST LOWER
MICHIGAN. NICE FLUFF FACTOR...HOWEVER...WITH LAKE INDUCED MOISTURE
AXIS REMAINING PEGGED IN THE DGZ...AS NOTED BY LARGE DENDRITIC
CONGLOMERATES FALLING HERE AT THE OFFICE. NO REPORTS YET...BUT NO
DOUBT AT LEAST SOME LIGHT ACCUMULATIONS OCCURRING UNDER WEAK BANDING
STRUCTURES. FORECAST CONCERNS THROUGH THE SHORT TERM CONTINUE TO
CENTER ON MESOSCALE LAKE SNOW TRENDS.
MARGINAL LAKE PROCESSES TO CONTINUE THROUGH TODAY AS SUFFICIENT
LAKE/AIR TEMPERATURE DIFFERENCE REMAINS PARTIALLY OFFSET BY LOW
INVERSION HEIGHTS AND LIMITED MOISTURE. MODEL DERIVED SOUNDINGS
CONCUR...WITH NOTED INVERTED-V DEVELOPMENT IN SURFACE BASED
ENVIRONMENT AS UPSTREAM DRY SURGE REPLACES CURRENT UPTICK IN LOW
LEVEL MOISTURE. "BEST" ACTIVITY EXPECTED EARLY ON THIS MORNING IN
FAVORED W TO WSW FLOW REGIMES OF NORTHWEST LOWER...WITH PERHAPS AN
ADDITIONAL INCH OR TWO UNDER THE MORE PERSISTENT BANDS. MUCH LIKE
YESTERDAY...EXPECT A DOWNWARD TREND IN BOTH INTENSITY AND COVERAGE
THROUGH THE DAY AS FLOW ONCE AGAIN BACKS AROUND TO SOUTHWEST BY THIS
AFTERNOON. POSSIBLY THINGS MAY END ALL TOGETHER (ALSO LIKE
YESTERDAY)...BUT DON`T WANT TO GO THIS OPTIMISTIC JUST YET. EITHER
WAY...NOT A BIG DEAL THIS AFTERNOON WITH ANY SNOW AMOUNTS LIKELY
REMAINING VERY LIGHT. NOT TOO SHABBY OF A DAY AWAY FROM THE FAVORED
LAKE PRONE AREAS OF NORTHWEST LOWER/SOUTHERN PORTIONS OF EASTERN
UPPER...WITH PARTLY TO MOSTLY CLOUDY SKIES AND TEMPERATURES IN THE
20S.
STORY REMAINS UNCHANGED THROUGH THIS EVENING WITH MARGINAL
INSTABILITY KICKING OFF SCATTERED LIGHT SNOW SHOWERS IN SOUTHWEST
FLOW AREAS. ALBERTA CLIPPER/COLD FRONT APPROACH THE WESTERN LAKES
LATE...WITH TRENDS SUPPORTING ATTENDANT MOISTURE AXIS NOT REACHING
OUR AREA UNTIL AFTER SUNRISE. WEAK PRE-FRONTAL WAA AND CONTINUOUS
FEED OF LOW LEVEL DRY AIR SHOULD CONTINUE TO SUBSTANTIALLY HINDER
LAKE PROCESSES THROUGH THE OVERNIGHT...DESPITE STEADY UPTICK IN
OVER-WATER WIND SPEEDS. EXPECT ANY SNOWFALL AMOUNTS TO REMAIN UNDER
AN INCH. UPTICK IN WINDS UNDER INCREASING PRESSURE GRADIENT REGIME
WILL OFFSET PARTLY TO MOSTLY CLEAR SKIES ELSEWHERE...NOT ALLOWING
TEMPERATURES TO DROP TOO MUCH. INHERITED LOW IN THE TEENS AND 20S
LOOK GREAT.
.LONG TERM...(WEDNESDAY THROUGH MONDAY)
ISSUED AT 346 AM EST TUE JAN 15 2013
WEDNESDAY AND WEDNESDAY NIGHT...UPPER LEVEL TROUGHING WILL BE
SITUATED OVER THE NRN GREAT LAKES...SHARPENED BY SHORTWAVE ENERGY
DIVING INTO THE REGION. THE ASSOCIATED CLIPPER/LOW PRESSURE WILL
PASS THROUGH ONTARIO...WITH A FAIRLY STRONG COLD FRONT TO CROSS
NRN MICHIGAN WEDNESDAY NIGHT. SW WINDS AHEAD OF THE FRONT WILL
GRADUALLY SHIFT AROUND TO OUT OF THE NW BY THURSDAY MORNING.
ENHANCED MOISTURE WITH THE FRONT WILL BRING SOME LIGHT SYNOPTIC
SNOWS WEDNESDAY...ENHANCED TO A MARGINAL DEGREE BY H8 TEMPS OF
-8C. NOT IMPRESSED WITH THE SNOWFALL INTENSITIES...AS INVERSION
HEIGHTS ONLY BRIEFLY RISE TO 5KFT...WITH WSW FLOW POINTING BEST
SNOWS ALONG FAR NW LOWER AND INTO EASTERN UPPER. LOWERED SNOWFALL
AMOUNTS BASED ON TURNING WINDS...AND ONLY A BRIEF PERIOD OF MORE
MODERATE ACTIVITY WITH THE FRONT. SECONDARY SHORTWAVE ENERGY AND
DEEPER MOISTURE WILL ENHANCE SNOW SHOWERS AT NIGHT...WHILE H8
TEMPS PLUMMET TO -22C NORTH/-16C SOUTH. AGAIN...WINDS ARE SHIFTING
OVER TIME...WITH INVERSION HEIGHTS 5KFT NORTH TO 4000 FEET SOUTH.
WHILE IT WILL OBVIOUSLY BE SNOWING FOR CATEGORICAL POPS...ACCUMS
NOT EXPECTED TO BE THRILLING AT 1-3" IN THE FAVORED AREAS FOR BOTH
OF THESE PERIODS (CHIP COUNTY IN EASTERN UPPER AND IN THE HIGHER
TERRAIN OF INTERIOR NRN LOWER AROUND GAYLORD. HIGHS AROUND 30F
WEDNESDAY WILL FALL INTO THE SINGLE DIGITS AND TEENS WEDNESDAY
NIGHT.
THURSDAY THROUGH FRIDAY...MOISTURE/COLD AIR REMAIN SUFFICIENT
THROUGH THURSDAY NIGHT FOR CONTINUED LIGHT LAKE EFFECT
ACCUMULATIONS. WNW WINDS WILL BE BACKING WITH TIME WITH LESS
MOISTURE. INVADING HIGHER PRESSURE WILL ALSO TURN THE WINDS MORE
ANTICYCLONIC THROUGH THEN WITH MAYBE A COUPLE OF INCHES IN SPOTS
IN NRN CHIP COUNTY AND FAR NW LOWER. THEN...THE NEXT CLIPPER
ARRIVES FRIDAY WITH STRONGER SW FLOW AND WARMING EXPECTED THROUGH
THE DAY FRIDAY. A WING OF WARM FRONTAL SYNOPTIC SNOWS...AND
BRIEF SW FLOW ENHANCEMENT FOR FRIDAY MORNING BEFORE THE
TEMPERATURES RISE/INVERSION HEIGHTS FALL.
FRIDAY NIGHT THROUGH EARLY NEXT WORK WEEK...LOW PRESSURE AND YET
ANOTHER COLD FRONT...SLOW MOVING...SLIDE IN ACROSS NRN MICHIGAN.
BEST LOW LEVEL CONVERGENCE AND RESULTING SNOWFALL WILL BE IN
EASTERN UPPER FRIDAY NIGHT INTO EARLY SATURDAY...BEFORE SHIFTING
SOUTH INTO NRN LOWER LATE SATURDAY AND SATURDAY NIGHT. WIND
DIRECTIONS ARE TOO UNCERTAIN AT THIS POINT...BUT DATA RIGHT NOW
SUGGESTS POOR NE FETCH ACROSS EASTERN UPPER...WITH BETTER NW FLOW
ACROSS NW LOWER FOR THE BEST ACCUMULATIONS. THE ASSOCIATED WAVE
ALOFT IS MORE DEFINED WITH EXPECTED MODEST DEEP LAYER -DIVQ. BY
SUNDAY...WINDS BACK AROUND OUT OF THE NW FOR EASTERN UPPER TO GET
BACK INTO THE LAKE EFFECT...ALONG WITH NW LOWER. SNOWS SUNDAY
NIGHT POSSIBLY ENHANCED YET AGAIN WITH NEXT IN THE SERIES OF
CLIPPERS/WAVES/SYNOPTIC SNOWFALL. LAKE EFFECT CONTINUES BEHIND
THIS CLIPPER INTO MONDAY AND TUESDAY.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z WEDNESDAY AFTERNOON)
ISSUED AT 1257 PM EST TUE JAN 15 2013
SOME MVFR CIGS DEVELOPING CLOSER TO THE LAKE MICHIGAN SHORELINE
THIS AFTERNOON WITH A FEW FLURRIES ALSO POSSIBLE. BY THIS
EVENING...DRIER AIR TEMPORARILY TAKES HOLD ONCE AGAIN AND SKIES
SHOULD SCATTER OUT. GRADIENT BEGINS TO TIGHTEN OVERNIGHT WITH
APPROACH OF COLD FRONT. DECIDED TO PUT LLWS IN THE TERMINALS AT
PLN/TVC/MBL...ALTHOUGH SURFACE WINDS MAY INCREASE ENOUGH LATER
TONIGHT TO LIMIT THIS IMPACT. STRONG COLD FRONT APPROACHES THE
AREA ON WEDNESDAY WITH THICKENING CLOUDS AND SNOWSHOWERS
DEVELOPING CLOSER TO LAKE MICHIGAN BY LATE MORNING. VERY TIGHT
PRESSURE GRADIENT AND WIND GUSTS OVER 30KTS POSSIBLE THROUGHOUT
MUCH OF THE DAY.
&&
.MARINE...
ISSUED AT 346 AM EST TUE JAN 15 2013
COMBINATION OF REMNANT OVER-WATER INSTABILITY AND TIGHTENING
PRESSURE GRADIENT AHEAD OF APPROACHING CLIPPER SYSTEM WILL RESULT
IN A QUICK INCREASE OF SOUTHWEST WINDS ACROSS NORTHERN LAKE
MICHIGAN AND THE STRAITS LATER THIS AFTERNOON...CONTINUING THROUGH
WEDNESDAY. GALES SEEM A CERTAINTY ACROSS CURRENT WATCH AREA
TONIGHT THROUGH WEDNESDAY...SO WILL UPGRADE AT THIS ISSUANCE. GALE
CONDITIONS SEEM INCREASINGLY POSSIBLE ALONG THE THE NORTHERN
PORTION OF LAKE HURON ON WEDNESDAY. STILL SOME LINGERING
UNCERTAINTY... ESPECIALLY ON TIMING. WILL ISSUE A GALE WATCH
WEDNESDAY INTO WEDNESDAY EVENING TO COVER THIS POTENTIAL.
THEREAFTER...A SEASONABLY ACTIVE PERIOD OF WEATHER IS EXPECTED
RIGHT ON INTO NEXT WEEKEND...WITH SEVERAL CLIPPER SYSTEMS CROSSING
THE WATERS... FOLLOWED BY PERIODS OF LAKE EFFECT SNOW. MORE ROUNDS
OF SMALL CRAFT ADVISORY WINDS ARE LIKELY THROUGHOUT THE LATE WEEK
AND WEEKEND.
&&
.APX WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LH...GALE WARNING FROM 7 PM THIS EVENING TO 4 PM EST WEDNESDAY FOR
LHZ345.
GALE WATCH FROM WEDNESDAY MORNING THROUGH WEDNESDAY EVENING FOR
LHZ346-347.
LM...GALE WARNING FROM 7 PM THIS EVENING TO 4 PM EST WEDNESDAY FOR
LMZ323-341-342-344>346.
LS...NONE.
&&
$$
UPDATE...JK
SYNOPSIS...SD
SHORT TERM...MB
LONG TERM...SD
AVIATION...JK
MARINE...MB
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
1215 PM EST TUE JAN 15 2013
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 500 AM EST TUE JAN 15 2013
WV IMAGERY AND RUC ANALYSIS INDICATED A RIDGE OFF THE WEST COAST AND
A BROAD MID/UPPER LEVEL TROUGH FROM NW OF HUDSON BAY THROUGH NRN
MANITOBA/NW ONTARIO AND THE CNTRL PLAINS INTO NEW MEXICO. THE NEXT
SIGNIFICANT SHORTWAVE TROUGH WAS WELL UPSTREAM YET OVER NW CANADA. AT
THE SFC...A RIDGE EXTENDED FROM THE MID MS VALLEY INTO THE SRN GREAT
LAKES RESULTING IN WSW FLOW THROUGH THE NRN LAKES. WEBCAMS AND MODEL
FCSTS SUGGEST THAT THE HEAVER LES BANDS HAD LIFTED MAINLY NORTH OF
CALUMET INTO THE N AND W PORTIONS OF KEWEENAW COUNTY. WAA 925-700 MB
WAA HELPED SUPPORT AN ARE OF LOW/MID CLOUDS AND A FEW FLURRIES FROM NRN
MN INTO NW WI AND WRN UPPER MI.
EXPECT THAT AS WINDS CONTINUE TO BACK THIS MORNING...ANY REMAINING
LES OVER THE TIP OF THE KEWEENAW WILL LIFT OUT INTO LAKE SUPERIOR
AROUND OR SLIGHTLY AFTER 12Z. SO...THE LES WARNING WILL BE ALLOWED
TO EXPIRE. OTHERWISE...NAM/RUC 925-700 MB RH FCST SUGGESTS THAT THE
CLOUDS SHOULD THIN OUT ENOUGH BY THIS AFTERNOON FOR AT LEAST SOME
SUNSHINE. TEMPS SHOULD CLIMB TO NEAR SEASONAL AVERAGES IN TO THE LOW
TO MID 20S.
THE MODELS WERE IN GOOD AGREEMENT WITH THE POSITION AND SPEED OF THE
NW CANADA CLIPPER SHRTWV MOVING TO JUST NW OF LAKE SUPERIOR BY
12Z/WED. THE GFS...AS IS OFTEN THE CASE WAS MORE AGGRESSIVE IN
SPREADING PCPN EASTWARD THROUGH UPPER MICHIGAN LATE TONIGHT COMPARED
TO THE NAM WHICH BARELY BRINGS ANY QPF TO THE WEST BEFORE 12Z.
ALTHOUGH THE DRY AIRMASS MAY DELAY THE ARRIVAL OF LIGHT SNOW AT THE
SURFACE...THE QVECTOR CONV AHEAD OF THE SHRTWV AND UPPER LEVEL DIV
WITH THE LEFT EXIT OF THE 250-300 MB JET STILL SHOULD BE ENOUGH FOR
LIKELY POPS OVER THE FAR WEST AND CHANCE POPS OVER THE REST OF THE
WEST HALF. SNOW AMOUNTS WILL BE LIGHT AS ONLY A FEW HUNDREDTHS QPF
SUPPORTS ACCUMULATIONS OF ONLY AROUND A HALF INCH OR LESS.
.LONG TERM...(WEDNESDAY THROUGH MONDAY)
ISSUED AT 500 AM EST TUE JAN 15 2013
LONG TERM PERIOD WILL BE DOMINATED BY NORTHWEST FLOW ALOFT AS AN
UPPER LOW SPINS NEAR HUDSON BAY. THIS WILL LEAD TO A SERIES OF
CLIPPER SYSTEMS AND ASSOCIATED COLDER AIR AND LAKE EFFECT ON THE
BACK SIDE.
THE FIRST SYSTEM WILL BE MOVING THROUGH AT THE START OF THE LONG
TERM PERIOD. THIS WAVE...CURRENTLY ROUNDING THE UPPER RIDGE ALONG
THE WESTERN COAST OF NORTH AMERICA...WILL BE SLIDING ACROSS LAKE
SUPERIOR WEDNESDAY MORNING. AT THE SURFACE...A COLD FRONT WILL BE
STRETCHED FROM A LOW IN SOUTHERN HUDSON BAY AND BE SWEEPING THROUGH
THE CWA THROUGH EARLY AFTERNOON. THE WIDESPREAD MOISTURE IS ACROSS
THE NORTH HALF OF THE CWA...WHILE A THIN RIBBON OF DEEP MOISTURE
MOVES ACROSS THE CWA LATE TONIGHT AND WEDNESDAY MORNING. ALTHOUGH
IT APPEARS THE SYSTEM WILL BE FIGHTING DRY LOW LEVEL AIR TO
START...MOST OF THE CWA SHOULD SEE A PERIOD OF LIGHT SNOW OR
FLURRIES. HIGH RES MODELS REALLY PICKING UP ON THE DRIER
AIR FOR THE CENTRAL CWA AND LIMITING QPF...SO WILL CONTINUE THAT
IDEA IN THE POPS AND SNOW AMOUNTS. BEST CHANCES FOR OVER AN INCH
WILL BE OVER THE WESTERN CWA AND EAST OF MUNISING.
BEHIND THIS FRONT...A PERIOD OF LAKE EFFECT IS EXPECTED WEDNESDAY
AFTERNOON INTO THURSDAY NIGHT. COLD AIR QUICKLY SURGES IN FROM THE
NORTHWEST ON WEDNESDAY AFTERNOON AND EVENING ACROSS THE
CWA...REACHING -25C BY 12Z THURSDAY. THIS PUTS MUCH OF THE CLOUD
LAYER ABOVE THE DGZ AND SHOULD LEAD TO LOWER SNOW RATIOS. WITH THAT
BEING SAID...STILL LOOKS LIKE VERY HIGH LAKE INDUCED EQL
VALUES...AROUND 10KFT...AND CAPE VALUES AROUND 900 J/KG. THERE IS
VERY DRY AIR ABOVE THE ACTUAL INVERSION AROUND 5KFT...SO WONDERING
IF THAT COMBINED WITH THE LOWER SNOW RATIOS WILL KEEP SNOWFALL
AMOUNTS FROM BEING TOO HEAVY WEDNESDAY NIGHT INTO THURSDAY.
ONE OTHER TREND TO MENTION IS THE IDEA OF A SURFACE TROUGH
LINGERING OVER EASTERN LAKE SUPERIOR LATE WEDNESDAY NIGHT AND
POTENTIALLY DEVELOPING INTO A WEAK LOW ON THURSDAY. EVEN THE COARSE
MODELS ARE STARTING TO SHOW THIS...WHICH IF IT OCCURS...MAY HELP
FOCUS AN AREA OF CONVERGENCE IN EASTERN ALGER AND LUCE COUNTIES FOR
HEAVIER SNOW. HIGH PRESSURE RIDGE SLIDES SOUTH OF THE AREA THURSDAY
AFTERNOON INTO THURSDAY NIGHT...WHICH WILL LEAD TO BACKING WINDS
AHEAD OF THE NEXT CLIPPER THAT WILL AFFECT THE AREA ON FRIDAY. THIS
WILL LEAD TO DRIER AIR ALOFT AND WARMING H850 TEMPS...WHICH
STRENGTHENS THE INVERSION TO AROUND 6KFT WHILE ALSO PUSHING THE DGZ
BACK INTO THE CLOUD LAYER. IN ADDITION...WITH THE WINDS LIKELY
BACKING MORE TO THE WEST...EXPECT THE LAKE EFFECT TO BE CONFINED TO
THE WESTERN CWA AND RIGHT ALONG THE SHORELINE OVER THE EAST IN THE
EVENING.
LOOKING AT CIPS ANALOG GUIDANCE...THE BEST FIT FOR THIS PERIOD IS
THE DECEMBER 10-11 1980 PERIOD...WHICH CORRELATES VERY WELL IN
H850 TEMPS ALTHOUGH THE SURFACE HIGH TO THE SOUTHWEST MAY BE
SLIGHTLY CLOSER TO THE CWA. 72-HR SNOWFALL AMOUNTS DURING THAT
PERIOD WERE GENERALLY IN THE 4-12 INCH RANGE...WHICH LENDS
CONFIDENCE TO THE GOING FORECAST THOUGHTS. IN ADDITION...LOOKING AT
PROBABILITIES FROM THE TOP 15 ANALOGS THEY SHOW A SIMILAR IDEA
FOR SNOW AMOUNTS...EVEN THOUGH THE MEAN H850 TEMPS ARE A LITTLE
WARMER THAN CURRENTLY EXPECTED. WILL CONTINUE TO MENTION MODERATE
SNOW IN THE HWO...SINCE SOME LOCATIONS WILL PROBABLY NEED LAKE
EFFECT SNOW ADVISORIES...DUE TO ADDITIONAL REDUCED VISIBILITIES WITH
THE FINER SNOWFLAKES AND SOME BLOWING SNOW. IN ADDITION...LOOKING AT
COOP TEMPERATURE OBSERVATIONS DURING THAT 1980 EVENING...THE GOING
IDEA OF HIGHS OF 10-15 AND LOWS AROUND ZERO LOOKS GOOD.
MODELS CONTINUE TO HAVE SUBTLE DIFFERENCES WITH THE CLIPPER
SYSTEM...BUT THE OVERALL IDEA OF IT TRAVERSING THE CWA SEEMS
REASONABLE FOR FRIDAY. SNOW LOOKS TO ARRIVE DURING THE LATER PART
OF THURSDAY NIGHT AND INTO FRIDAY...UNDER THE STRONG H850 WAA. AT
THIS POINT...LOOKS LIKE ANOTHER DUSTING OF AROUND AN INCH OF SNOW.
THE WARMING SOUTHWEST FLOW WILL ALSO PUSH HIGHS 10-15 DEGREES
WARMER THAN THURSDAY.
AFTER THAT...CONFIDENCE QUICKLY DROPS IN THE FORECAST...AS THERE
ARE VARYING TIMES AT WHICH THE NEXT STRONGER SHORTWAVE ARRIVES.
00Z GFS IS FASTER AND ARRIVES EARLY SATURDAY...WHILE THE 00Z
ECMWF/GEM HAVE IT ARRIVING SATURDAY AFTERNOON. FOR THIS TIME OF THE
YEAR...THESE DIFFERENCES MAKE A HUGE DIFFERENCES FOR THE FORECAST
DUE TO WIND FIELDS...H850 TEMPS...AND POTENTIAL FOR LAKE EFFECT.
WILL JUST GO WITH A GENERAL CHANCE POPS FOR THE ENTIRE AREA...WITH
THE HIGHEST VALUES NEAR LAKE SUPERIOR.
ONCE THIS WAVE DEPARTS...LOOKS TO BE ANOTHER PERIOD OF MULTI-BAND
LAKE EFFECT FOR THE NORTHWEST WIND LAKE EFFECT AREAS SUNDAY INTO
MONDAY. AFTER BECOMING DISRUPTED SOME WITH THE LAST SHORTWAVE...THE
UPPER TROUGH WILL AGAIN REESTABLISH ITSELF OVER THE GREAT LAKES
THROUGH THE FIRST PART OF NEXT WEEK. H850 TEMPS WILL AGAIN BE AROUND
-25C AND LEAD TO PERIODS OF MODERATE LAKE EFFECT SNOW. WILL BUMP
POPS UP BASED OFF LOCAL LAKE EFFECT CLIMATOLOGY GRIDS TO HIGH
CHANCE OR LOW LIKELY VALUES FOR NORTHWEST WIND LOCATIONS.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z WEDNESDAY AFTERNOON)
ISSUED AT 1214 PM EST TUE JAN 15 2013
VFR CONDITIONS WILL CONTINUE THROUGH THE OVERNIGHT HOURS AT ALL 3
SITES BEFORE AN ALBERTA CLIPPER COMES IN AND GIVES SOME LIGHT SNOW
TO THE AREA. TOOK CONDITIONS DOWN TO IFR AT CMX AND IWD FOR THIS AND
MVFR AT SAW BY WED MORNING. ALTHOUGH WINDS WILL BE MAINLY
DECOUPLED...EXPECT GUSTY CONDITIONS AT IWD MAY LIMIT LLWS POTENTIAL.
DID PUT IN SOME LLWS TONIGHT AT SAW BEFORE GUSTY CONDITIONS DEVELOP
LATE TONIGHT. SW WINDS AT CMX ARE NOT GUSTY IN GENERAL DUE TO
TERRAIN.
&&
.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 500 AM EST TUE JAN 15 2013
SOUTHWEST WINDS WILL INCREASE THIS AFTERNOON AND TONIGHT AHEAD OF
AN APPROACHING COLD FRONT. THIS WILL PRODUCE GALES TO 35-40KTS AND
WILL CONTINUE THE GALE WARNING FOR TONIGHT INTO WEDNESDAY. WINDS
WILL SHIFT TO THE WEST AND THEN NORTHWEST AND GUST TO 40KTS DURING
THE DAY WEDNESDAY BEHIND THE FRONT. NORTHWEST WINDS OF 15-30KTS
WILL CONTINUE WEDNESDAY NIGHT INTO THURSDAY...WITH OCCASIONAL GALE
FORCE GUSTS TO 35KTS. A SERIES OF CLIPPER SYSTEMS ARE EXPECTED TO
MOVE THROUGH ON FRIDAY AND AGAIN ON SATURDAY. THIS WILL DISRUPT THE
WINDS SOME DURING THOSE PERIODS...WITH NORTH-NORTHWEST WINDS TO
30KTS AGAIN EXPECTED SATURDAY NIGHT.
FINALLY...HEAVY FREEZING SPRAY IS EXPECTED WEDNESDAY NIGHT INTO
THURSDAY EVENING OVER MUCH OF LAKE SUPERIOR.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
GALE WARNING FROM 7 PM THIS EVENING TO 7 PM EST WEDNESDAY FOR
LSZ264>267.
GALE WARNING FROM 7 PM EST /6 PM CST/ THIS EVENING TO 1 PM EST
/NOON CST/ WEDNESDAY FOR LSZ162-263.
GALE WARNING FROM 1 AM TO 7 PM EST WEDNESDAY FOR LSZ244-245-
249>251.
GALE WARNING FROM 1 PM TO 7 PM EST WEDNESDAY FOR LSZ248.
GALE WARNING FROM 1 AM EST /MIDNIGHT CST/ TO 1 PM EST /NOON CST/
WEDNESDAY FOR LSZ240>243.
LAKE MICHIGAN...
GALE WARNING FROM 4 AM TO 1 PM EST WEDNESDAY FOR LMZ221-248-250.
&&
$$
SHORT TERM...JLB
LONG TERM...SRF
AVIATION...07
MARINE...SRF
AREA FORECAST DISCUSSION
NWS GAYLORD MI
1024 AM EST TUE JAN 15 2013
.SYNOPSIS...
ISSUED AT 346 AM EST TUE JAN 15 2013
SEVERAL AREAS OF LOW PRESSURE AND COLD FRONTS WILL CROSS NORTHERN
MICHIGAN OVER THE NEXT SEVERAL DAYS. THIS WILL PRODUCE PERIODS OF
LAKE EFFECT AND LAKE ENHANCED SNOW SHOWERS...WHICH WILL PRIMARILY
AFFECT EASTERN UPPER AND NORTHWEST LOWER MICHIGAN.
&&
.UPDATE...
ISSUED AT 935 AM EST TUE JAN 15 2013
STRATO-CU HAS LARGELY ERODED THIS MORNING AS DEEP DRY AIR ABOVE
850MB MIXES OUT LOW LEVEL MOISTURE. STILL SEEING AN AREA OF LOW
LEVEL MOISTURE HUGGING THE LAKE MICHIGAN SHORELINE FROM FRANKFORT
SOUTHWARD. WILL LARGELY DISREGARD THE "MOIST" NAM TODAY...WHICH
IS MUCH TOO PESSIMISTIC WITH WIDESPREAD CLOUDINESS ACROSS
NORTHERN MICHIGAN THIS AFTERNOON. COMBO OF LINGERING LOW LEVEL
MOISTURE ALONG THE COASTLINE AND A FEW UPSTREAM PATCHES OF MID
CLOUD OVER WISCONSIN MAY INTERACT WITH STILL PLENTIFUL OVERLAKE
INSTABILITY TO PRODUCE A FEW AFTN FLURRIES CLOSER TO THE LAKE
MICHIGAN COAST. INLAND AREAS SHOULD SEE A GOOD AMOUNT OF SUNSHINE.
CURRENT TEMP FORECAST LOOKS GOOD AND WILL MAKE ONLY SOME MINOR
CHANGES BASED ON CURRENT OBSERVATIONS.
UPDATE ISSUED AT 639 AM EST TUE JAN 15 2013
BIG UPDATES EARLY THIS MORNING...AS THE STRATO CU OFF THE LAKES
HAS RAPIDLY ERODED...LEAVING CLEARING SKIES MOST AREAS...WITH ONLY
SOME SCATTERED FLURRIES. WITH NO DISCERNIBLE MID LEVEL CLOUD
UPSTREAM...OUTSIDE OF A SMALL AREAS IN NORTH CENTRAL
WISCONSIN...WILL DISREGARD NAM/GFS TRAPPED IN SHALLOW STRATO CU
MOSTLY CLOUDY SKY FOR THE DAY. RATHER...WILL OPT TO KEEP SKIES ON
THE CLEARER SIDE FOR THE DAY. THIS AGREED UPON BY LATEST RUC DATA.
AS WINDS INCREASE TONIGHT...MAYBE SOME ADDITIONAL MOISTURE FLUX
OFF THE LAKES...BUT EVEN HERE...DATA SUGGESTS THAT THE ATMOSPHERE
DRIES OUT LATE...PRIOR TO NEXT UPSTREAM CLIPPER/COLD FRONT SET FOR
WEDNESDAY.
&&
.SHORT TERM...(TODAY THROUGH TONIGHT)
ISSUED AT 346 AM EST TUE JAN 15 2013
EARLY MORNING REGIONAL ANALYSIS SHOWS HIGH PRESSURE STRETCHED OUT
ACROSS THE WESTERN LAKES ON FRONT SIDE OF POSITIVELY TILTED DEEP MID
LEVEL TROUGH AXIS EXTENDING FROM HUDSON BAY DOWN TO NEAR THE FOUR
CORNERS. LIGHT WSW FLOW CONTINUES TO ROTATE AROUND NORTH EDGE OF
SURFACE RIDGE AXIS ACROSS THE NORTHERN LAKES. THIS...COMBINED WITH
MORE THAN SUFFICIENT DELTA T/S (RAP ANALYSIS SHOWS H85 TEMPS IN THE
NEGATIVE MID TEENS) AND SLIGHT UPTICK IN LOW LEVEL MOISTURE...HAS
KICKED OFF GENERALLY LIGHT LAKE INDUCED SNOWS ACROSS NORTHWEST LOWER
MICHIGAN. NICE FLUFF FACTOR...HOWEVER...WITH LAKE INDUCED MOISTURE
AXIS REMAINING PEGGED IN THE DGZ...AS NOTED BY LARGE DENDRITIC
CONGLOMERATES FALLING HERE AT THE OFFICE. NO REPORTS YET...BUT NO
DOUBT AT LEAST SOME LIGHT ACCUMULATIONS OCCURRING UNDER WEAK BANDING
STRUCTURES. FORECAST CONCERNS THROUGH THE SHORT TERM CONTINUE TO
CENTER ON MESOSCALE LAKE SNOW TRENDS.
MARGINAL LAKE PROCESSES TO CONTINUE THROUGH TODAY AS SUFFICIENT
LAKE/AIR TEMPERATURE DIFFERENCE REMAINS PARTIALLY OFFSET BY LOW
INVERSION HEIGHTS AND LIMITED MOISTURE. MODEL DERIVED SOUNDINGS
CONCUR...WITH NOTED INVERTED-V DEVELOPMENT IN SURFACE BASED
ENVIRONMENT AS UPSTREAM DRY SURGE REPLACES CURRENT UPTICK IN LOW
LEVEL MOISTURE. "BEST" ACTIVITY EXPECTED EARLY ON THIS MORNING IN
FAVORED W TO WSW FLOW REGIMES OF NORTHWEST LOWER...WITH PERHAPS AN
ADDITIONAL INCH OR TWO UNDER THE MORE PERSISTENT BANDS. MUCH LIKE
YESTERDAY...EXPECT A DOWNWARD TREND IN BOTH INTENSITY AND COVERAGE
THROUGH THE DAY AS FLOW ONCE AGAIN BACKS AROUND TO SOUTHWEST BY THIS
AFTERNOON. POSSIBLY THINGS MAY END ALL TOGETHER (ALSO LIKE
YESTERDAY)...BUT DON`T WANT TO GO THIS OPTIMISTIC JUST YET. EITHER
WAY...NOT A BIG DEAL THIS AFTERNOON WITH ANY SNOW AMOUNTS LIKELY
REMAINING VERY LIGHT. NOT TOO SHABBY OF A DAY AWAY FROM THE FAVORED
LAKE PRONE AREAS OF NORTHWEST LOWER/SOUTHERN PORTIONS OF EASTERN
UPPER...WITH PARTLY TO MOSTLY CLOUDY SKIES AND TEMPERATURES IN THE
20S.
STORY REMAINS UNCHANGED THROUGH THIS EVENING WITH MARGINAL
INSTABILITY KICKING OFF SCATTERED LIGHT SNOW SHOWERS IN SOUTHWEST
FLOW AREAS. ALBERTA CLIPPER/COLD FRONT APPROACH THE WESTERN LAKES
LATE...WITH TRENDS SUPPORTING ATTENDANT MOISTURE AXIS NOT REACHING
OUR AREA UNTIL AFTER SUNRISE. WEAK PRE-FRONTAL WAA AND CONTINUOUS
FEED OF LOW LEVEL DRY AIR SHOULD CONTINUE TO SUBSTANTIALLY HINDER
LAKE PROCESSES THROUGH THE OVERNIGHT...DESPITE STEADY UPTICK IN
OVER-WATER WIND SPEEDS. EXPECT ANY SNOWFALL AMOUNTS TO REMAIN UNDER
AN INCH. UPTICK IN WINDS UNDER INCREASING PRESSURE GRADIENT REGIME
WILL OFFSET PARTLY TO MOSTLY CLEAR SKIES ELSEWHERE...NOT ALLOWING
TEMPERATURES TO DROP TOO MUCH. INHERITED LOW IN THE TEENS AND 20S
LOOK GREAT.
.LONG TERM...(WEDNESDAY THROUGH MONDAY)
ISSUED AT 346 AM EST TUE JAN 15 2013
WEDNESDAY AND WEDNESDAY NIGHT...UPPER LEVEL TROUGHING WILL BE
SITUATED OVER THE NRN GREAT LAKES...SHARPENED BY SHORTWAVE ENERGY
DIVING INTO THE REGION. THE ASSOCIATED CLIPPER/LOW PRESSURE WILL
PASS THROUGH ONTARIO...WITH A FAIRLY STRONG COLD FRONT TO CROSS
NRN MICHIGAN WEDNESDAY NIGHT. SW WINDS AHEAD OF THE FRONT WILL
GRADUALLY SHIFT AROUND TO OUT OF THE NW BY THURSDAY MORNING.
ENHANCED MOISTURE WITH THE FRONT WILL BRING SOME LIGHT SYNOPTIC
SNOWS WEDNESDAY...ENHANCED TO A MARGINAL DEGREE BY H8 TEMPS OF
-8C. NOT IMPRESSED WITH THE SNOWFALL INTENSITIES...AS INVERSION
HEIGHTS ONLY BRIEFLY RISE TO 5KFT...WITH WSW FLOW POINTING BEST
SNOWS ALONG FAR NW LOWER AND INTO EASTERN UPPER. LOWERED SNOWFALL
AMOUNTS BASED ON TURNING WINDS...AND ONLY A BRIEF PERIOD OF MORE
MODERATE ACTIVITY WITH THE FRONT. SECONDARY SHORTWAVE ENERGY AND
DEEPER MOISTURE WILL ENHANCE SNOW SHOWERS AT NIGHT...WHILE H8
TEMPS PLUMMET TO -22C NORTH/-16C SOUTH. AGAIN...WINDS ARE SHIFTING
OVER TIME...WITH INVERSION HEIGHTS 5KFT NORTH TO 4000 FEET SOUTH.
WHILE IT WILL OBVIOUSLY BE SNOWING FOR CATEGORICAL POPS...ACCUMS
NOT EXPECTED TO BE THRILLING AT 1-3" IN THE FAVORED AREAS FOR BOTH
OF THESE PERIODS (CHIP COUNTY IN EASTERN UPPER AND IN THE HIGHER
TERRAIN OF INTERIOR NRN LOWER AROUND GAYLORD. HIGHS AROUND 30F
WEDNESDAY WILL FALL INTO THE SINGLE DIGITS AND TEENS WEDNESDAY
NIGHT.
THURSDAY THROUGH FRIDAY...MOISTURE/COLD AIR REMAIN SUFFICIENT
THROUGH THURSDAY NIGHT FOR CONTINUED LIGHT LAKE EFFECT
ACCUMULATIONS. WNW WINDS WILL BE BACKING WITH TIME WITH LESS
MOISTURE. INVADING HIGHER PRESSURE WILL ALSO TURN THE WINDS MORE
ANTICYCLONIC THROUGH THEN WITH MAYBE A COUPLE OF INCHES IN SPOTS
IN NRN CHIP COUNTY AND FAR NW LOWER. THEN...THE NEXT CLIPPER
ARRIVES FRIDAY WITH STRONGER SW FLOW AND WARMING EXPECTED THROUGH
THE DAY FRIDAY. A WING OF WARM FRONTAL SYNOPTIC SNOWS...AND
BRIEF SW FLOW ENHANCEMENT FOR FRIDAY MORNING BEFORE THE
TEMPERATURES RISE/INVERSION HEIGHTS FALL.
FRIDAY NIGHT THROUGH EARLY NEXT WORK WEEK...LOW PRESSURE AND YET
ANOTHER COLD FRONT...SLOW MOVING...SLIDE IN ACROSS NRN MICHIGAN.
BEST LOW LEVEL CONVERGENCE AND RESULTING SNOWFALL WILL BE IN
EASTERN UPPER FRIDAY NIGHT INTO EARLY SATURDAY...BEFORE SHIFTING
SOUTH INTO NRN LOWER LATE SATURDAY AND SATURDAY NIGHT. WIND
DIRECTIONS ARE TOO UNCERTAIN AT THIS POINT...BUT DATA RIGHT NOW
SUGGESTS POOR NE FETCH ACROSS EASTERN UPPER...WITH BETTER NW FLOW
ACROSS NW LOWER FOR THE BEST ACCUMULATIONS. THE ASSOCIATED WAVE
ALOFT IS MORE DEFINED WITH EXPECTED MODEST DEEP LAYER -DIVQ. BY
SUNDAY...WINDS BACK AROUND OUT OF THE NW FOR EASTERN UPPER TO GET
BACK INTO THE LAKE EFFECT...ALONG WITH NW LOWER. SNOWS SUNDAY
NIGHT POSSIBLY ENHANCED YET AGAIN WITH NEXT IN THE SERIES OF
CLIPPERS/WAVES/SYNOPTIC SNOWFALL. LAKE EFFECT CONTINUES BEHIND
THIS CLIPPER INTO MONDAY AND TUESDAY.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z WEDNESDAY MORNING)
ISSUED AT 639 AM EST TUE JAN 15 2013
LOW LEVEL MVFR CIGS HAVE RAPIDLY ERODED...AS DRIER AIR HAS
OVERPOWERED THE LAKE EFFECT. COULD BE A BRIEF PERIOD OR TWO THAT
THESE CLOUDS WILL BE ABLE TO DEVELOP TODAY...BUT SOME UNCERTAINTY
DOES EXIST. LATEST SATELLITE AND RAPID UPDATE DATA SUGGEST THE
CLEARER SCENARIO IS THE ONE TO FOLLOW. MAYBE THIS CLOUD CAN
BRIEFLY FIRE UP THIS EVENING AS SW/WSW WINDS INCREASE IN ADVANCE
OF A CLIPPER SYSTEM/COLD FRONT SET FOR WEDNESDAY...BUT AGAIN...AIR
MASS DRIES LATE IN THE PERIOD. PREVAILING CONDITIONS EXPECTED TO
BE VFR. AS WINDS INCREASE LATE TONIGHT...WIND SHEAR ISSUES
INCREASE...BUT BELIEVE AT THIS POINT...THERE WILL BE ENOUGH OF A
SFC WIND TO PREVENT THE INTRODUCTION OF LLWS INTO THE FORECAST.
&&
.MARINE...
ISSUED AT 346 AM EST TUE JAN 15 2013
COMBINATION OF REMNANT OVER-WATER INSTABILITY AND TIGHTENING
PRESSURE GRADIENT AHEAD OF APPROACHING CLIPPER SYSTEM WILL RESULT
IN A QUICK INCREASE OF SOUTHWEST WINDS ACROSS NORTHERN LAKE
MICHIGAN AND THE STRAITS LATER THIS AFTERNOON...CONTINUING THROUGH
WEDNESDAY. GALES SEEM A CERTAINTY ACROSS CURRENT WATCH AREA
TONIGHT THROUGH WEDNESDAY...SO WILL UPGRADE AT THIS ISSUANCE. GALE
CONDITIONS SEEM INCREASINGLY POSSIBLE ALONG THE THE NORTHERN
PORTION OF LAKE HURON ON WEDNESDAY. STILL SOME LINGERING
UNCERTAINTY... ESPECIALLY ON TIMING. WILL ISSUE A GALE WATCH
WEDNESDAY INTO WEDNESDAY EVENING TO COVER THIS POTENTIAL.
THEREAFTER...A SEASONABLY ACTIVE PERIOD OF WEATHER IS EXPECTED
RIGHT ON INTO NEXT WEEKEND...WITH SEVERAL CLIPPER SYSTEMS CROSSING
THE WATERS... FOLLOWED BY PERIODS OF LAKE EFFECT SNOW. MORE ROUNDS
OF SMALL CRAFT ADVISORY WINDS ARE LIKELY THROUGHOUT THE LATE WEEK
AND WEEKEND.
&&
.APX WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LH...GALE WARNING FROM 7 PM THIS EVENING TO 4 PM EST WEDNESDAY FOR
LHZ345.
GALE WATCH FROM WEDNESDAY MORNING THROUGH WEDNESDAY EVENING FOR
LHZ346-347.
LM...GALE WARNING FROM 7 PM THIS EVENING TO 4 PM EST WEDNESDAY FOR
LMZ323-341-342-344>346.
LS...NONE.
&&
$$
UPDATE...JK
SYNOPSIS...SD
SHORT TERM...MB
LONG TERM...SD
AVIATION...SD
MARINE...MB
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
703 AM EST TUE JAN 15 2013
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 500 AM EST TUE JAN 15 2013
WV IMAGERY AND RUC ANALYSIS INDICATED A RIDGE OFF THE WEST COAST AND
A BROAD MID/UPPER LEVEL TROUGH FROM NW OF HUDSON BAY THROUGH NRN
MANITOBA/NW ONTARIO AND THE CNTRL PLAINS INTO NEW MEXICO. THE NEXT
SIGNIFICANT SHORTWAVE TROUGH WAS WELL UPSTREAM YET OVER NW CANADA. AT
THE SFC...A RIDGE EXTENDED FROM THE MID MS VALLEY INTO THE SRN GREAT
LAKES RESULTING IN WSW FLOW THROUGH THE NRN LAKES. WEBCAMS AND MODEL
FCSTS SUGGEST THAT THE HEAVER LES BANDS HAD LIFTED MAINLY NORTH OF
CALUMET INTO THE N AND W PORTIONS OF KEWEENAW COUNTY. WAA 925-700 MB
WAA HELPED SUPPORT AN ARE OF LOW/MID CLOUDS AND A FEW FLURRIES FROM NRN
MN INTO NW WI AND WRN UPPER MI.
EXPECT THAT AS WINDS CONTINUE TO BACK THIS MORNING...ANY REMAINING
LES OVER THE TIP OF THE KEWEENAW WILL LIFT OUT INTO LAKE SUPERIOR
AROUND OR SLIGHTLY AFTER 12Z. SO...THE LES WARNING WILL BE ALLOWED
TO EXPIRE. OTHERWISE...NAM/RUC 925-700 MB RH FCST SUGGESTS THAT THE
CLOUDS SHOULD THIN OUT ENOUGH BY THIS AFTERNOON FOR AT LEAST SOME
SUNSHINE. TEMPS SHOULD CLIMB TO NEAR SEASONAL AVERAGES IN TO THE LOW
TO MID 20S.
THE MODELS WERE IN GOOD AGREEMENT WITH THE POSITION AND SPEED OF THE
NW CANADA CLIPPER SHRTWV MOVING TO JUST NW OF LAKE SUPERIOR BY
12Z/WED. THE GFS...AS IS OFTEN THE CASE WAS MORE AGGRESSIVE IN
SPREADING PCPN EASTWARD THROUGH UPPER MICHIGAN LATE TONIGHT COMPARED
TO THE NAM WHICH BARELY BRINGS ANY QPF TO THE WEST BEFORE 12Z.
ALTHOUGH THE DRY AIRMASS MAY DELAY THE ARRIVAL OF LIGHT SNOW AT THE
SURFACE...THE QVECTOR CONV AHEAD OF THE SHRTWV AND UPPER LEVEL DIV
WITH THE LEFT EXIT OF THE 250-300 MB JET STILL SHOULD BE ENOUGH FOR
LIKELY POPS OVER THE FAR WEST AND CHANCE POPS OVER THE REST OF THE
WEST HALF. SNOW AMOUNTS WILL BE LIGHT AS ONLY A FEW HUNDREDTHS QPF
SUPPORTS ACCUMULATIONS OF ONLY AROUND A HALF INCH OR LESS.
.LONG TERM...(WEDNESDAY THROUGH MONDAY)
ISSUED AT 500 AM EST TUE JAN 15 2013
LONG TERM PERIOD WILL BE DOMINATED BY NORTHWEST FLOW ALOFT AS AN
UPPER LOW SPINS NEAR HUDSON BAY. THIS WILL LEAD TO A SERIES OF
CLIPPER SYSTEMS AND ASSOCIATED COLDER AIR AND LAKE EFFECT ON THE
BACK SIDE.
THE FIRST SYSTEM WILL BE MOVING THROUGH AT THE START OF THE LONG
TERM PERIOD. THIS WAVE...CURRENTLY ROUNDING THE UPPER RIDGE ALONG
THE WESTERN COAST OF NORTH AMERICA...WILL BE SLIDING ACROSS LAKE
SUPERIOR WEDNESDAY MORNING. AT THE SURFACE...A COLD FRONT WILL BE
STRETCHED FROM A LOW IN SOUTHERN HUDSON BAY AND BE SWEEPING THROUGH
THE CWA THROUGH EARLY AFTERNOON. THE WIDESPREAD MOISTURE IS ACROSS
THE NORTH HALF OF THE CWA...WHILE A THIN RIBBON OF DEEP MOISTURE
MOVES ACROSS THE CWA LATE TONIGHT AND WEDNESDAY MORNING. ALTHOUGH
IT APPEARS THE SYSTEM WILL BE FIGHTING DRY LOW LEVEL AIR TO
START...MOST OF THE CWA SHOULD SEE A PERIOD OF LIGHT SNOW OR
FLURRIES. HIGH RES MODELS REALLY PICKING UP ON THE DRIER
AIR FOR THE CENTRAL CWA AND LIMITING QPF...SO WILL CONTINUE THAT
IDEA IN THE POPS AND SNOW AMOUNTS. BEST CHANCES FOR OVER AN INCH
WILL BE OVER THE WESTERN CWA AND EAST OF MUNISING.
BEHIND THIS FRONT...A PERIOD OF LAKE EFFECT IS EXPECTED WEDNESDAY
AFTERNOON INTO THURSDAY NIGHT. COLD AIR QUICKLY SURGES IN FROM THE
NORTHWEST ON WEDNESDAY AFTERNOON AND EVENING ACROSS THE
CWA...REACHING -25C BY 12Z THURSDAY. THIS PUTS MUCH OF THE CLOUD
LAYER ABOVE THE DGZ AND SHOULD LEAD TO LOWER SNOW RATIOS. WITH THAT
BEING SAID...STILL LOOKS LIKE VERY HIGH LAKE INDUCED EQL
VALUES...AROUND 10KFT...AND CAPE VALUES AROUND 900 J/KG. THERE IS
VERY DRY AIR ABOVE THE ACTUAL INVERSION AROUND 5KFT...SO WONDERING
IF THAT COMBINED WITH THE LOWER SNOW RATIOS WILL KEEP SNOWFALL
AMOUNTS FROM BEING TOO HEAVY WEDNESDAY NIGHT INTO THURSDAY.
ONE OTHER TREND TO MENTION IS THE IDEA OF A SURFACE TROUGH
LINGERING OVER EASTERN LAKE SUPERIOR LATE WEDNESDAY NIGHT AND
POTENTIALLY DEVELOPING INTO A WEAK LOW ON THURSDAY. EVEN THE COARSE
MODELS ARE STARTING TO SHOW THIS...WHICH IF IT OCCURS...MAY HELP
FOCUS AN AREA OF CONVERGENCE IN EASTERN ALGER AND LUCE COUNTIES FOR
HEAVIER SNOW. HIGH PRESSURE RIDGE SLIDES SOUTH OF THE AREA THURSDAY
AFTERNOON INTO THURSDAY NIGHT...WHICH WILL LEAD TO BACKING WINDS
AHEAD OF THE NEXT CLIPPER THAT WILL AFFECT THE AREA ON FRIDAY. THIS
WILL LEAD TO DRIER AIR ALOFT AND WARMING H850 TEMPS...WHICH
STRENGTHENS THE INVERSION TO AROUND 6KFT WHILE ALSO PUSHING THE DGZ
BACK INTO THE CLOUD LAYER. IN ADDITION...WITH THE WINDS LIKELY
BACKING MORE TO THE WEST...EXPECT THE LAKE EFFECT TO BE CONFINED TO
THE WESTERN CWA AND RIGHT ALONG THE SHORELINE OVER THE EAST IN THE
EVENING.
LOOKING AT CIPS ANALOG GUIDANCE...THE BEST FIT FOR THIS PERIOD IS
THE DECEMBER 10-11 1980 PERIOD...WHICH CORRELATES VERY WELL IN
H850 TEMPS ALTHOUGH THE SURFACE HIGH TO THE SOUTHWEST MAY BE
SLIGHTLY CLOSER TO THE CWA. 72-HR SNOWFALL AMOUNTS DURING THAT
PERIOD WERE GENERALLY IN THE 4-12 INCH RANGE...WHICH LENDS
CONFIDENCE TO THE GOING FORECAST THOUGHTS. IN ADDITION...LOOKING AT
PROBABILITIES FROM THE TOP 15 ANALOGS THEY SHOW A SIMILAR IDEA
FOR SNOW AMOUNTS...EVEN THOUGH THE MEAN H850 TEMPS ARE A LITTLE
WARMER THAN CURRENTLY EXPECTED. WILL CONTINUE TO MENTION MODERATE
SNOW IN THE HWO...SINCE SOME LOCATIONS WILL PROBABLY NEED LAKE
EFFECT SNOW ADVISORIES...DUE TO ADDITIONAL REDUCED VISIBILITIES WITH
THE FINER SNOWFLAKES AND SOME BLOWING SNOW. IN ADDITION...LOOKING AT
COOP TEMPERATURE OBSERVATIONS DURING THAT 1980 EVENING...THE GOING
IDEA OF HIGHS OF 10-15 AND LOWS AROUND ZERO LOOKS GOOD.
MODELS CONTINUE TO HAVE SUBTLE DIFFERENCES WITH THE CLIPPER
SYSTEM...BUT THE OVERALL IDEA OF IT TRAVERSING THE CWA SEEMS
REASONABLE FOR FRIDAY. SNOW LOOKS TO ARRIVE DURING THE LATER PART
OF THURSDAY NIGHT AND INTO FRIDAY...UNDER THE STRONG H850 WAA. AT
THIS POINT...LOOKS LIKE ANOTHER DUSTING OF AROUND AN INCH OF SNOW.
THE WARMING SOUTHWEST FLOW WILL ALSO PUSH HIGHS 10-15 DEGREES
WARMER THAN THURSDAY.
AFTER THAT...CONFIDENCE QUICKLY DROPS IN THE FORECAST...AS THERE
ARE VARYING TIMES AT WHICH THE NEXT STRONGER SHORTWAVE ARRIVES.
00Z GFS IS FASTER AND ARRIVES EARLY SATURDAY...WHILE THE 00Z
ECMWF/GEM HAVE IT ARRIVING SATURDAY AFTERNOON. FOR THIS TIME OF THE
YEAR...THESE DIFFERENCES MAKE A HUGE DIFFERENCES FOR THE FORECAST
DUE TO WIND FIELDS...H850 TEMPS...AND POTENTIAL FOR LAKE EFFECT.
WILL JUST GO WITH A GENERAL CHANCE POPS FOR THE ENTIRE AREA...WITH
THE HIGHEST VALUES NEAR LAKE SUPERIOR.
ONCE THIS WAVE DEPARTS...LOOKS TO BE ANOTHER PERIOD OF MULTI-BAND
LAKE EFFECT FOR THE NORTHWEST WIND LAKE EFFECT AREAS SUNDAY INTO
MONDAY. AFTER BECOMING DISRUPTED SOME WITH THE LAST SHORTWAVE...THE
UPPER TROUGH WILL AGAIN REESTABLISH ITSELF OVER THE GREAT LAKES
THROUGH THE FIRST PART OF NEXT WEEK. H850 TEMPS WILL AGAIN BE AROUND
-25C AND LEAD TO PERIODS OF MODERATE LAKE EFFECT SNOW. WILL BUMP
POPS UP BASED OFF LOCAL LAKE EFFECT CLIMATOLOGY GRIDS TO HIGH
CHANCE OR LOW LIKELY VALUES FOR NORTHWEST WIND LOCATIONS.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z WEDNESDAY MORNING)
ISSUED AT 701 AM EST TUE JAN 15 2013
AN AREA OF MID CLOUDS WITH MAINLY VFR CIGS WILL COVER THE AREA EARLY
TODAY. THERE MAY BE A BRIEF PERIOD OF MVFR CIGS AT IWD.
HOWEVER...EXPECT THE CIGS TO DISSIPATE BY AFTERNOON WITH DRIER AIR
MOVING IN FROM THE WEST. AS A SHORTWAVE TROUGH AND LOW PRESSURE
SYSTEM APPROACH THE AREA FROM THE NORTHWEST...SOUTHWEST WINDS WILL
INCREASE TODAY AND TONIGHT. ALTHOUGH WINDS WILL BE SOMEWHAT
DECOUPLED...EXPECT GUSTY CONDITIONS MAY LIMIT LLWS POTENTIAL. SOME
LIGHT SNOW MAY ALSO MOVE IN LATE OVER THE WEST BUT IS NOT EXPECTED TO
REDUCE CONDITIONS INTO THE MVFR RANGE BEFORE 12Z/WED.
&&
.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 500 AM EST TUE JAN 15 2013
SOUTHWEST WINDS WILL INCREASE THIS AFTERNOON AND TONIGHT AHEAD OF
AN APPROACHING COLD FRONT. THIS WILL PRODUCE GALES TO 35-40KTS AND
WILL CONTINUE THE GALE WARNING FOR TONIGHT INTO WEDNESDAY. WINDS
WILL SHIFT TO THE WEST AND THEN NORTHWEST AND GUST TO 40KTS DURING
THE DAY WEDNESDAY BEHIND THE FRONT. NORTHWEST WINDS OF 15-30KTS
WILL CONTINUE WEDNESDAY NIGHT INTO THURSDAY...WITH OCCASIONAL GALE
FORCE GUSTS TO 35KTS. A SERIES OF CLIPPER SYSTEMS ARE EXPECTED TO
MOVE THROUGH ON FRIDAY AND AGAIN ON SATURDAY. THIS WILL DISRUPT THE
WINDS SOME DURING THOSE PERIODS...WITH NORTH-NORTHWEST WINDS TO
30KTS AGAIN EXPECTED SATURDAY NIGHT.
FINALLY...HEAVY FREEZING SPRAY IS EXPECTED WEDNESDAY NIGHT INTO
THURSDAY EVENING OVER MUCH OF LAKE SUPERIOR.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
GALE WARNING FROM 7 PM THIS EVENING TO 7 PM EST WEDNESDAY FOR
LSZ264>267.
GALE WARNING FROM 7 PM EST /6 PM CST/ THIS EVENING TO 1 PM EST
/NOON CST/ WEDNESDAY FOR LSZ162-263.
GALE WARNING FROM 1 AM TO 7 PM EST WEDNESDAY FOR LSZ244-245-
249>251.
GALE WARNING FROM 1 PM TO 7 PM EST WEDNESDAY FOR LSZ248.
GALE WARNING FROM 1 AM EST /MIDNIGHT CST/ TO 1 PM EST /NOON CST/
WEDNESDAY FOR LSZ240>243.
LAKE MICHIGAN...
GALE WARNING FROM 4 AM TO 1 PM EST WEDNESDAY FOR LMZ221-248-250.
&&
$$
SHORT TERM...JLB
LONG TERM...SRF
AVIATION...JLB
MARINE...SRF
AREA FORECAST DISCUSSION
NWS GAYLORD MI
649 AM EST TUE JAN 15 2013
.SYNOPSIS...
ISSUED AT 346 AM EST TUE JAN 15 2013
SEVERAL AREAS OF LOW PRESSURE AND COLD FRONTS WILL CROSS NORTHERN
MICHIGAN OVER THE NEXT SEVERAL DAYS. THIS WILL PRODUCE PERIODS OF
LAKE EFFECT AND LAKE ENHANCED SNOW SHOWERS...WHICH WILL PRIMARILY
AFFECT EASTERN UPPER AND NORTHWEST LOWER MICHIGAN.
&&
.UPDATE...
ISSUED AT 639 AM EST TUE JAN 15 2013
BIG UPDATES EARLY THIS MORNING...AS THE STRATO CU OFF THE LAKES
HAS RAPIDLY ERODED...LEAVING CLEARING SKIES MOST AREAS...WITH ONLY
SOME SCATTERED FLURRIES. WITH NO DISCERNIBLE MID LEVEL CLOUD
UPSTREAM...OUTSIDE OF A SMALL AREAS IN NORTH CENTRAL
WISCONSIN...WILL DISREGARD NAM/GFS TRAPPED IN SHALLOW STRATO CU
MOSTLY CLOUDY SKY FOR THE DAY. RATHER...WILL OPT TO KEEP SKIES ON
THE CLEARER SIDE FOR THE DAY. THIS AGREED UPON BY LATEST RUC DATA.
AS WINDS INCREASE TONIGHT...MAYBE SOME ADDITIONAL MOISTURE FLUX
OFF THE LAKES...BUT EVEN HERE...DATA SUGGESTS THAT THE ATMOSPHERE
DRIES OUT LATE...PRIOR TO NEXT UPSTREAM CLIPPER/COLD FRONT SET FOR
WEDNESDAY.
&&
.SHORT TERM...(TODAY THROUGH TONIGHT)
ISSUED AT 346 AM EST TUE JAN 15 2013
EARLY MORNING REGIONAL ANALYSIS SHOWS HIGH PRESSURE STRETCHED OUT
ACROSS THE WESTERN LAKES ON FRONT SIDE OF POSITIVELY TILTED DEEP MID
LEVEL TROUGH AXIS EXTENDING FROM HUDSON BAY DOWN TO NEAR THE FOUR
CORNERS. LIGHT WSW FLOW CONTINUES TO ROTATE AROUND NORTH EDGE OF
SURFACE RIDGE AXIS ACROSS THE NORTHERN LAKES. THIS...COMBINED WITH
MORE THAN SUFFICIENT DELTA T/S (RAP ANALYSIS SHOWS H85 TEMPS IN THE
NEGATIVE MID TEENS) AND SLIGHT UPTICK IN LOW LEVEL MOISTURE...HAS
KICKED OFF GENERALLY LIGHT LAKE INDUCED SNOWS ACROSS NORTHWEST LOWER
MICHIGAN. NICE FLUFF FACTOR...HOWEVER...WITH LAKE INDUCED MOISTURE
AXIS REMAINING PEGGED IN THE DGZ...AS NOTED BY LARGE DENDRITIC
CONGLOMERATES FALLING HERE AT THE OFFICE. NO REPORTS YET...BUT NO
DOUBT AT LEAST SOME LIGHT ACCUMULATIONS OCCURRING UNDER WEAK BANDING
STRUCTURES. FORECAST CONCERNS THROUGH THE SHORT TERM CONTINUE TO
CENTER ON MESOSCALE LAKE SNOW TRENDS.
MARGINAL LAKE PROCESSES TO CONTINUE THROUGH TODAY AS SUFFICIENT
LAKE/AIR TEMPERATURE DIFFERENCE REMAINS PARTIALLY OFFSET BY LOW
INVERSION HEIGHTS AND LIMITED MOISTURE. MODEL DERIVED SOUNDINGS
CONCUR...WITH NOTED INVERTED-V DEVELOPMENT IN SURFACE BASED
ENVIRONMENT AS UPSTREAM DRY SURGE REPLACES CURRENT UPTICK IN LOW
LEVEL MOISTURE. "BEST" ACTIVITY EXPECTED EARLY ON THIS MORNING IN
FAVORED W TO WSW FLOW REGIMES OF NORTHWEST LOWER...WITH PERHAPS AN
ADDITIONAL INCH OR TWO UNDER THE MORE PERSISTENT BANDS. MUCH LIKE
YESTERDAY...EXPECT A DOWNWARD TREND IN BOTH INTENSITY AND COVERAGE
THROUGH THE DAY AS FLOW ONCE AGAIN BACKS AROUND TO SOUTHWEST BY THIS
AFTERNOON. POSSIBLY THINGS MAY END ALL TOGETHER (ALSO LIKE
YESTERDAY)...BUT DON`T WANT TO GO THIS OPTIMISTIC JUST YET. EITHER
WAY...NOT A BIG DEAL THIS AFTERNOON WITH ANY SNOW AMOUNTS LIKELY
REMAINING VERY LIGHT. NOT TOO SHABBY OF A DAY AWAY FROM THE FAVORED
LAKE PRONE AREAS OF NORTHWEST LOWER/SOUTHERN PORTIONS OF EASTERN
UPPER...WITH PARTLY TO MOSTLY CLOUDY SKIES AND TEMPERATURES IN THE
20S.
STORY REMAINS UNCHANGED THROUGH THIS EVENING WITH MARGINAL
INSTABILITY KICKING OFF SCATTERED LIGHT SNOW SHOWERS IN SOUTHWEST
FLOW AREAS. ALBERTA CLIPPER/COLD FRONT APPROACH THE WESTERN LAKES
LATE...WITH TRENDS SUPPORTING ATTENDANT MOISTURE AXIS NOT REACHING
OUR AREA UNTIL AFTER SUNRISE. WEAK PRE-FRONTAL WAA AND CONTINUOUS
FEED OF LOW LEVEL DRY AIR SHOULD CONTINUE TO SUBSTANTIALLY HINDER
LAKE PROCESSES THROUGH THE OVERNIGHT...DESPITE STEADY UPTICK IN
OVER-WATER WIND SPEEDS. EXPECT ANY SNOWFALL AMOUNTS TO REMAIN UNDER
AN INCH. UPTICK IN WINDS UNDER INCREASING PRESSURE GRADIENT REGIME
WILL OFFSET PARTLY TO MOSTLY CLEAR SKIES ELSEWHERE...NOT ALLOWING
TEMPERATURES TO DROP TOO MUCH. INHERITED LOW IN THE TEENS AND 20S
LOOK GREAT.
.LONG TERM...(WEDNESDAY THROUGH MONDAY)
ISSUED AT 346 AM EST TUE JAN 15 2013
WEDNESDAY AND WEDNESDAY NIGHT...UPPER LEVEL TROUGHING WILL BE
SITUATED OVER THE NRN GREAT LAKES...SHARPENED BY SHORTWAVE ENERGY
DIVING INTO THE REGION. THE ASSOCIATED CLIPPER/LOW PRESSURE WILL
PASS THROUGH ONTARIO...WITH A FAIRLY STRONG COLD FRONT TO CROSS
NRN MICHIGAN WEDNESDAY NIGHT. SW WINDS AHEAD OF THE FRONT WILL
GRADUALLY SHIFT AROUND TO OUT OF THE NW BY THURSDAY MORNING.
ENHANCED MOISTURE WITH THE FRONT WILL BRING SOME LIGHT SYNOPTIC
SNOWS WEDNESDAY...ENHANCED TO A MARGINAL DEGREE BY H8 TEMPS OF
-8C. NOT IMPRESSED WITH THE SNOWFALL INTENSITIES...AS INVERSION
HEIGHTS ONLY BRIEFLY RISE TO 5KFT...WITH WSW FLOW POINTING BEST
SNOWS ALONG FAR NW LOWER AND INTO EASTERN UPPER. LOWERED SNOWFALL
AMOUNTS BASED ON TURNING WINDS...AND ONLY A BRIEF PERIOD OF MORE
MODERATE ACTIVITY WITH THE FRONT. SECONDARY SHORTWAVE ENERGY AND
DEEPER MOISTURE WILL ENHANCE SNOW SHOWERS AT NIGHT...WHILE H8
TEMPS PLUMMET TO -22C NORTH/-16C SOUTH. AGAIN...WINDS ARE SHIFTING
OVER TIME...WITH INVERSION HEIGHTS 5KFT NORTH TO 4000 FEET SOUTH.
WHILE IT WILL OBVIOUSLY BE SNOWING FOR CATEGORICAL POPS...ACCUMS
NOT EXPECTED TO BE THRILLING AT 1-3" IN THE FAVORED AREAS FOR BOTH
OF THESE PERIODS (CHIP COUNTY IN EASTERN UPPER AND IN THE HIGHER
TERRAIN OF INTERIOR NRN LOWER AROUND GAYLORD. HIGHS AROUND 30F
WEDNESDAY WILL FALL INTO THE SINGLE DIGITS AND TEENS WEDNESDAY
NIGHT.
THURSDAY THROUGH FRIDAY...MOISTURE/COLD AIR REMAIN SUFFICIENT
THROUGH THURSDAY NIGHT FOR CONTINUED LIGHT LAKE EFFECT
ACCUMULATIONS. WNW WINDS WILL BE BACKING WITH TIME WITH LESS
MOISTURE. INVADING HIGHER PRESSURE WILL ALSO TURN THE WINDS MORE
ANTICYCLONIC THROUGH THEN WITH MAYBE A COUPLE OF INCHES IN SPOTS
IN NRN CHIP COUNTY AND FAR NW LOWER. THEN...THE NEXT CLIPPER
ARRIVES FRIDAY WITH STRONGER SW FLOW AND WARMING EXPECTED THROUGH
THE DAY FRIDAY. A WING OF WARM FRONTAL SYNOPTIC SNOWS...AND
BRIEF SW FLOW ENHANCEMENT FOR FRIDAY MORNING BEFORE THE
TEMPERATURES RISE/INVERSION HEIGHTS FALL.
FRIDAY NIGHT THROUGH EARLY NEXT WORK WEEK...LOW PRESSURE AND YET
ANOTHER COLD FRONT...SLOW MOVING...SLIDE IN ACROSS NRN MICHIGAN.
BEST LOW LEVEL CONVERGENCE AND RESULTING SNOWFALL WILL BE IN
EASTERN UPPER FRIDAY NIGHT INTO EARLY SATURDAY...BEFORE SHIFTING
SOUTH INTO NRN LOWER LATE SATURDAY AND SATURDAY NIGHT. WIND
DIRECTIONS ARE TOO UNCERTAIN AT THIS POINT...BUT DATA RIGHT NOW
SUGGESTS POOR NE FETCH ACROSS EASTERN UPPER...WITH BETTER NW FLOW
ACROSS NW LOWER FOR THE BEST ACCUMULATIONS. THE ASSOCIATED WAVE
ALOFT IS MORE DEFINED WITH EXPECTED MODEST DEEP LAYER -DIVQ. BY
SUNDAY...WINDS BACK AROUND OUT OF THE NW FOR EASTERN UPPER TO GET
BACK INTO THE LAKE EFFECT...ALONG WITH NW LOWER. SNOWS SUNDAY
NIGHT POSSIBLY ENHANCED YET AGAIN WITH NEXT IN THE SERIES OF
CLIPPERS/WAVES/SYNOPTIC SNOWFALL. LAKE EFFECT CONTINUES BEHIND
THIS CLIPPER INTO MONDAY AND TUESDAY.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z WEDNESDAY MORNING)
ISSUED AT 639 AM EST TUE JAN 15 2013
LOW LEVEL MVFR CIGS HAVE RAPIDLY ERODED...AS DRIER AIR HAS
OVERPOWERED THE LAKE EFFECT. COULD BE A BRIEF PERIOD OR TWO THAT
THESE CLOUDS WILL BE ABLE TO DEVELOP TODAY...BUT SOME UNCERTAINTY
DOES EXIST. LATEST SATELLITE AND RAPID UPDATE DATA SUGGEST THE
CLEARER SCENARIO IS THE ONE TO FOLLOW. MAYBE THIS CLOUD CAN
BRIEFLY FIRE UP THIS EVENING AS SW/WSW WINDS INCREASE IN ADVANCE
OF A CLIPPER SYSTEM/COLD FRONT SET FOR WEDNESDAY...BUT AGAIN...AIR
MASS DRIES LATE IN THE PERIOD. PREVAILING CONDITIONS EXPECTED TO
BE VFR. AS WINDS INCREASE LATE TONIGHT...WIND SHEAR ISSUES
INCREASE...BUT BELIEVE AT THIS POINT...THERE WILL BE ENOUGH OF A
SFC WIND TO PREVENT THE INTRODUCTION OF LLWS INTO THE FORECAST.
&&
.MARINE...
ISSUED AT 346 AM EST TUE JAN 15 2013
COMBINATION OF REMNANT OVER-WATER INSTABILITY AND TIGHTENING
PRESSURE GRADIENT AHEAD OF APPROACHING CLIPPER SYSTEM WILL RESULT
IN A QUICK INCREASE OF SOUTHWEST WINDS ACROSS NORTHERN LAKE
MICHIGAN AND THE STRAITS LATER THIS AFTERNOON...CONTINUING THROUGH
WEDNESDAY. GALES SEEM A CERTAINTY ACROSS CURRENT WATCH AREA
TONIGHT THROUGH WEDNESDAY...SO WILL UPGRADE AT THIS ISSUANCE. GALE
CONDITIONS SEEM INCREASINGLY POSSIBLE ALONG THE THE NORTHERN
PORTION OF LAKE HURON ON WEDNESDAY. STILL SOME LINGERING
UNCERTAINTY... ESPECIALLY ON TIMING. WILL ISSUE A GALE WATCH
WEDNESDAY INTO WEDNESDAY EVENING TO COVER THIS POTENTIAL.
THEREAFTER...A SEASONABLY ACTIVE PERIOD OF WEATHER IS EXPECTED
RIGHT ON INTO NEXT WEEKEND...WITH SEVERAL CLIPPER SYSTEMS CROSSING
THE WATERS... FOLLOWED BY PERIODS OF LAKE EFFECT SNOW. MORE ROUNDS
OF SMALL CRAFT ADVISORY WINDS ARE LIKELY THROUGHOUT THE LATE WEEK
AND WEEKEND.
&&
.APX WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LH...GALE WARNING FROM 7 PM THIS EVENING TO 4 PM EST WEDNESDAY FOR
LHZ345.
GALE WATCH FROM WEDNESDAY MORNING THROUGH WEDNESDAY EVENING FOR
LHZ346-347.
LM...GALE WARNING FROM 7 PM THIS EVENING TO 4 PM EST WEDNESDAY FOR
LMZ323-341-342-344>346.
LS...NONE.
&&
$$
UPDATE...SD
SYNOPSIS...SD
SHORT TERM...MB
LONG TERM...SD
AVIATION...SD
MARINE...MB
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
500 AM EST TUE JAN 15 2013
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 500 AM EST TUE JAN 15 2013
WV IMAGERY AND RUC ANALYSIS INDICATED A RIDGE OFF THE WEST COAST AND
A BROAD MID/UPPER LEVEL TROUGH FROM NW OF HUDSON BAY THROUGH NRN
MANITOBA/NW ONTARIO AND THE CNTRL PLAINS INTO NEW MEXICO. THE NEXT
SIGNIFICANT SHORTWAVE TROUGH WAS WELL UPSTREAM YET OVER NW CANADA. AT
THE SFC...A RIDGE EXTENDED FROM THE MID MS VALLEY INTO THE SRN GREAT
LAKES RESULTING IN WSW FLOW THROUGH THE NRN LAKES. WEBCAMS AND MODEL
FCSTS SUGGEST THAT THE HEAVER LES BANDS HAD LIFTED MAINLY NORTH OF
CALUMET INTO THE N AND W PORTIONS OF KEWEENAW COUNTY. WAA 925-700 MB
WAA HELPED SUPPORT AN ARE OF LOW/MID CLOUDS AND A FEW FLURRIES FROM NRN
MN INTO NW WI AND WRN UPPER MI.
EXPECT THAT AS WINDS CONTINUE TO BACK THIS MORNING...ANY REMAINING
LES OVER THE TIP OF THE KEWEENAW WILL LIFT OUT INTO LAKE SUPERIOR
AROUND OR SLIGHTLY AFTER 12Z. SO...THE LES WARNING WILL BE ALLOWED
TO EXPIRE. OTHERWISE...NAM/RUC 925-700 MB RH FCST SUGGESTS THAT THE
CLOUDS SHOULD THIN OUT ENOUGH BY THIS AFTERNOON FOR AT LEAST SOME
SUNSHINE. TEMPS SHOULD CLIMB TO NEAR SEASONAL AVERAGES IN TO THE LOW
TO MID 20S.
THE MODELS WERE IN GOOD AGREEMENT WITH THE POSITION AND SPEED OF THE
NW CANADA CLIPPER SHRTWV MOVING TO JUST NW OF LAKE SUPERIOR BY
12Z/WED. THE GFS...AS IS OFTEN THE CASE WAS MORE AGGRESSIVE IN
SPREADING PCPN EASTWARD THROUGH UPPER MICHIGAN LATE TONIGHT COMPARED
TO THE NAM WHICH BARELY BRINGS ANY QPF TO THE WEST BEFORE 12Z.
ALTHOUGH THE DRY AIRMASS MAY DELAY THE ARRIVAL OF LIGHT SNOW AT THE
SURFACE...THE QVECTOR CONV AHEAD OF THE SHRTWV AND UPPER LEVEL DIV
WITH THE LEFT EXIT OF THE 250-300 MB JET STILL SHOULD BE ENOUGH FOR
LIKELY POPS OVER THE FAR WEST AND CHANCE POPS OVER THE REST OF THE
WEST HALF. SNOW AMOUNTS WILL BE LIGHT AS ONLY A FEW HUNDREDTHS QPF
SUPPORTS ACCUMULATIONS OF ONLY AROUND A HALF INCH OR LESS.
.LONG TERM...(WEDNESDAY THROUGH MONDAY)
ISSUED AT 500 AM EST TUE JAN 15 2013
LONG TERM PERIOD WILL BE DOMINATED BY NORTHWEST FLOW ALOFT AS AN
UPPER LOW SPINS NEAR HUDSON BAY. THIS WILL LEAD TO A SERIES OF
CLIPPER SYSTEMS AND ASSOCIATED COLDER AIR AND LAKE EFFECT ON THE
BACK SIDE.
THE FIRST SYSTEM WILL BE MOVING THROUGH AT THE START OF THE LONG
TERM PERIOD. THIS WAVE...CURRENTLY ROUNDING THE UPPER RIDGE ALONG
THE WESTERN COAST OF NORTH AMERICA...WILL BE SLIDING ACROSS LAKE
SUPERIOR WEDNESDAY MORNING. AT THE SURFACE...A COLD FRONT WILL BE
STRETCHED FROM A LOW IN SOUTHERN HUDSON BAY AND BE SWEEPING THROUGH
THE CWA THROUGH EARLY AFTERNOON. THE WIDESPREAD MOISTURE IS ACROSS
THE NORTH HALF OF THE CWA...WHILE A THIN RIBBON OF DEEP MOISTURE
MOVES ACROSS THE CWA LATE TONIGHT AND WEDNESDAY MORNING. ALTHOUGH
IT APPEARS THE SYSTEM WILL BE FIGHTING DRY LOW LEVEL AIR TO
START...MOST OF THE CWA SHOULD SEE A PERIOD OF LIGHT SNOW OR
FLURRIES. HIGH RES MODELS REALLY PICKING UP ON THE DRIER
AIR FOR THE CENTRAL CWA AND LIMITING QPF...SO WILL CONTINUE THAT
IDEA IN THE POPS AND SNOW AMOUNTS. BEST CHANCES FOR OVER AN INCH
WILL BE OVER THE WESTERN CWA AND EAST OF MUNISING.
BEHIND THIS FRONT...A PERIOD OF LAKE EFFECT IS EXPECTED WEDNESDAY
AFTERNOON INTO THURSDAY NIGHT. COLD AIR QUICKLY SURGES IN FROM THE
NORTHWEST ON WEDNESDAY AFTERNOON AND EVENING ACROSS THE
CWA...REACHING -25C BY 12Z THURSDAY. THIS PUTS MUCH OF THE CLOUD
LAYER ABOVE THE DGZ AND SHOULD LEAD TO LOWER SNOW RATIOS. WITH THAT
BEING SAID...STILL LOOKS LIKE VERY HIGH LAKE INDUCED EQL
VALUES...AROUND 10KFT...AND CAPE VALUES AROUND 900 J/KG. THERE IS
VERY DRY AIR ABOVE THE ACTUAL INVERSION AROUND 5KFT...SO WONDERING
IF THAT COMBINED WITH THE LOWER SNOW RATIOS WILL KEEP SNOWFALL
AMOUNTS FROM BEING TOO HEAVY WEDNESDAY NIGHT INTO THURSDAY.
ONE OTHER TREND TO MENTION IS THE IDEA OF A SURFACE TROUGH
LINGERING OVER EASTERN LAKE SUPERIOR LATE WEDNESDAY NIGHT AND
POTENTIALLY DEVELOPING INTO A WEAK LOW ON THURSDAY. EVEN THE COARSE
MODELS ARE STARTING TO SHOW THIS...WHICH IF IT OCCURS...MAY HELP
FOCUS AN AREA OF CONVERGENCE IN EASTERN ALGER AND LUCE COUNTIES FOR
HEAVIER SNOW. HIGH PRESSURE RIDGE SLIDES SOUTH OF THE AREA THURSDAY
AFTERNOON INTO THURSDAY NIGHT...WHICH WILL LEAD TO BACKING WINDS
AHEAD OF THE NEXT CLIPPER THAT WILL AFFECT THE AREA ON FRIDAY. THIS
WILL LEAD TO DRIER AIR ALOFT AND WARMING H850 TEMPS...WHICH
STRENGTHENS THE INVERSION TO AROUND 6KFT WHILE ALSO PUSHING THE DGZ
BACK INTO THE CLOUD LAYER. IN ADDITION...WITH THE WINDS LIKELY
BACKING MORE TO THE WEST...EXPECT THE LAKE EFFECT TO BE CONFINED TO
THE WESTERN CWA AND RIGHT ALONG THE SHORELINE OVER THE EAST IN THE
EVENING.
LOOKING AT CIPS ANALOG GUIDANCE...THE BEST FIT FOR THIS PERIOD IS
THE DECEMBER 10-11 1980 PERIOD...WHICH CORRELATES VERY WELL IN
H850 TEMPS ALTHOUGH THE SURFACE HIGH TO THE SOUTHWEST MAY BE
SLIGHTLY CLOSER TO THE CWA. 72-HR SNOWFALL AMOUNTS DURING THAT
PERIOD WERE GENERALLY IN THE 4-12 INCH RANGE...WHICH LENDS
CONFIDENCE TO THE GOING FORECAST THOUGHTS. IN ADDITION...LOOKING AT
PROBABILITIES FROM THE TOP 15 ANALOGS THEY SHOW A SIMILAR IDEA
FOR SNOW AMOUNTS...EVEN THOUGH THE MEAN H850 TEMPS ARE A LITTLE
WARMER THAN CURRENTLY EXPECTED. WILL CONTINUE TO MENTION MODERATE
SNOW IN THE HWO...SINCE SOME LOCATIONS WILL PROBABLY NEED LAKE
EFFECT SNOW ADVISORIES...DUE TO ADDITIONAL REDUCED VISIBILITIES WITH
THE FINER SNOWFLAKES AND SOME BLOWING SNOW. IN ADDITION...LOOKING AT
COOP TEMPERATURE OBSERVATIONS DURING THAT 1980 EVENING...THE GOING
IDEA OF HIGHS OF 10-15 AND LOWS AROUND ZERO LOOKS GOOD.
MODELS CONTINUE TO HAVE SUBTLE DIFFERENCES WITH THE CLIPPER
SYSTEM...BUT THE OVERALL IDEA OF IT TRAVERSING THE CWA SEEMS
REASONABLE FOR FRIDAY. SNOW LOOKS TO ARRIVE DURING THE LATER PART
OF THURSDAY NIGHT AND INTO FRIDAY...UNDER THE STRONG H850 WAA. AT
THIS POINT...LOOKS LIKE ANOTHER DUSTING OF AROUND AN INCH OF SNOW.
THE WARMING SOUTHWEST FLOW WILL ALSO PUSH HIGHS 10-15 DEGREES
WARMER THAN THURSDAY.
AFTER THAT...CONFIDENCE QUICKLY DROPS IN THE FORECAST...AS THERE
ARE VARYING TIMES AT WHICH THE NEXT STRONGER SHORTWAVE ARRIVES.
00Z GFS IS FASTER AND ARRIVES EARLY SATURDAY...WHILE THE 00Z
ECMWF/GEM HAVE IT ARRIVING SATURDAY AFTERNOON. FOR THIS TIME OF THE
YEAR...THESE DIFFERENCES MAKE A HUGE DIFFERENCES FOR THE FORECAST
DUE TO WIND FIELDS...H850 TEMPS...AND POTENTIAL FOR LAKE EFFECT.
WILL JUST GO WITH A GENERAL CHANCE POPS FOR THE ENTIRE AREA...WITH
THE HIGHEST VALUES NEAR LAKE SUPERIOR.
ONCE THIS WAVE DEPARTS...LOOKS TO BE ANOTHER PERIOD OF MULTI-BAND
LAKE EFFECT FOR THE NORTHWEST WIND LAKE EFFECT AREAS SUNDAY INTO
MONDAY. AFTER BECOMING DISRUPTED SOME WITH THE LAST SHORTWAVE...THE
UPPER TROUGH WILL AGAIN REESTABLISH ITSELF OVER THE GREAT LAKES
THROUGH THE FIRST PART OF NEXT WEEK. H850 TEMPS WILL AGAIN BE AROUND
-25C AND LEAD TO PERIODS OF MODERATE LAKE EFFECT SNOW. WILL BUMP
POPS UP BASED OFF LOCAL LAKE EFFECT CLIMATOLOGY GRIDS TO HIGH
CHANCE OR LOW LIKELY VALUES FOR NORTHWEST WIND LOCATIONS.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z TUESDAY NIGHT)
ISSUED AT 1209 AM EST TUE JAN 15 2013
CMX...EXPECT PREDOMINANT MVFR/OCNL IFR CONDITIONS EARLY IN THE FCST
PERIOD UNDER ONGOING LAKE EFFECT SHSN. AS THE LLVL FLOW BACKS MORE
TO THE SW EARLY THIS MRNG...EXPECT THE SHSN TO SHIFT TO THE N OF THE
SITE AND CONDITIONS TO TRANSITION TO PRIMARILY VFR. ANOTHER
DISTURBANCE WL BRING MORE CLDS AND PSBLY MORE MVFR CIGS THRU THE
REST OF THE MRNG PER UPSTREAM OBS IN MN. CIGS WL THEN RETURN TO VFR
FOLLOWING THE PASSAGE OF THIS DISTURBANCE BY AFTN. AS A STRONGER SW
GRADIENT FLOW DEVELOPS THIS AFTN...THERE MAY BE SOME GUSTY
WINDS...WHICH WL TRANSITION TO LLWS TNGT WITH NOCTURNAL COOLING
LIMITING MIXING TO THE SFC. SINCE THIS SW FLOW WL BE DRY...
CONDITIONS WL REMAIN VFR.
IWD...AN APRCHG DISTURBANCE WL BRING VFR CIGS TRANSITIONING TO MVFR
BY 12Z PER UPSTREAM OBS IN MN. CIGS WL THEN RETURN TO VFR FOLLOWING
THE PASSAGE OF THIS DISTURBANCE BY AFTN. AS A STRONGER SW GRADIENT
FLOW DEVELOPS THIS AFTN...THERE MAY BE SOME GUSTY WINDS...WHICH WL
TRANSITION TO LLWS TNGT WITH NOCTURNAL COOLING LIMITING MIXING TO
THE SFC. SINCE THIS SW FLOW WL BE DRY...CONDITIONS WL REMAIN VFR.
SAW...EXPECT VFR CONDITIONS THRU SUNRISE. ALTHOUGH AN APRCHG
DISTURBANCE MIGHT BRING MORE CLDS LATER THIS MRNG...SUSPECT CIGS WL
REMAIN IN THE VFR RANGE. AS A STRONGER SW GRADIENT FLOW DEVELOPS
THIS AFTN...THERE MAY BE SOME GUSTY WINDS...WHICH WL TRANSITION TO
LLWS TNGT WITH NOCTURNAL COOLING LIMITING MIXING TO THE SFC. SINCE
THIS SW FLOW WL BE DRY...CONDITIONS WL REMAIN VFR.
&&
.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 500 AM EST TUE JAN 15 2013
SOUTHWEST WINDS WILL INCREASE THIS AFTERNOON AND TONIGHT AHEAD OF
AN APPROACHING COLD FRONT. THIS WILL PRODUCE GALES TO 35-40KTS AND
WILL CONTINUE THE GALE WARNING FOR TONIGHT INTO WEDNESDAY. WINDS
WILL SHIFT TO THE WEST AND THEN NORTHWEST AND GUST TO 40KTS DURING
THE DAY WEDNESDAY BEHIND THE FRONT. NORTHWEST WINDS OF 15-30KTS
WILL CONTINUE WEDNESDAY NIGHT INTO THURSDAY...WITH OCCASIONAL GALE
FORCE GUSTS TO 35KTS. A SERIES OF CLIPPER SYSTEMS ARE EXPECTED TO
MOVE THROUGH ON FRIDAY AND AGAIN ON SATURDAY. THIS WILL DISRUPT THE
WINDS SOME DURING THOSE PERIODS...WITH NORTH-NORTHWEST WINDS TO
30KTS AGAIN EXPECTED SATURDAY NIGHT.
FINALLY...HEAVY FREEZING SPRAY IS EXPECTED WEDNESDAY NIGHT INTO
THURSDAY EVENING OVER MUCH OF LAKE SUPERIOR.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
LAKE EFFECT SNOW WARNING UNTIL 7 AM EST THIS MORNING FOR MIZ001-
003.
LAKE SUPERIOR...
GALE WARNING FROM 7 PM THIS EVENING TO 7 PM EST WEDNESDAY FOR
LSZ264>267.
GALE WARNING FROM 7 PM EST /6 PM CST/ THIS EVENING TO 1 PM EST
/NOON CST/ WEDNESDAY FOR LSZ162-263.
GALE WARNING FROM 1 AM TO 7 PM EST WEDNESDAY FOR LSZ244-245-
249>251.
GALE WARNING FROM 1 PM TO 7 PM EST WEDNESDAY FOR LSZ248.
GALE WARNING FROM 1 AM EST /MIDNIGHT CST/ TO 1 PM EST /NOON CST/
WEDNESDAY FOR LSZ240>243.
LAKE MICHIGAN...
GALE WARNING FROM 4 AM TO 1 PM EST WEDNESDAY FOR LMZ221-248-250.
&&
$$
SHORT TERM...JLB
LONG TERM...SRF
AVIATION...KC
MARINE...SRF
AREA FORECAST DISCUSSION
NWS HASTINGS NE
1229 AM CST TUE JAN 15 2013
.AVIATION...06Z KGRI TAF. SOME MVFR STRATUS WITH A FEW FLURRIES IS
CURRENTLY TO THE WEST/NORTHWEST OF THE TERMINAL NEAR LBF AND
JUST NORTH OF ODX. THIS CONTINUES TO STREAM AND EXPAND
NORTHEASTWARD WITHOUT MUCH EASTWARD PROGRESSION TOWARD KGRI. SOME
SCATTERED VFR SKY COVER IS DETECTED ON SATELLITE EAST OF THE MAIN
AREA OF STRATUS...BUT THE STRATUS SHOULD REMAIN WEST OF THE
TERMINAL OVERNIGHT BEFORE MIXING OUT DURING THE DAY ON TUESDAY.
WIND SHOULD REMAIN RELATIVELY LIGHT WITH ANY REDUCED VISIBILITY
EXPECTED TO REMAIN WITH LIGHT SNOW/FLURRY ACTIVITY ASSOCIATED WITH
THE STRATUS TO THE WEST/NORTHWEST.
&&
.PREV DISCUSSION... /ISSUED 910 PM CST MON JAN 14 2013/
UPDATE...AS OF 03Z WATER VAPOR IMAGERY INDICATES A LONGWAVE
TROUGH ACROSS THE CENTRAL CONUS. A WEAK RIDGE OF HIGH PRESSURE IS
ALSO NOTED AT THE SURFACE OVER PORTIONS OF THE MISSOURI VALLEY.
LOW LEVEL RETURN FLOW IS BEING OBSERVED OVER PORTIONS OF WESTERN
KANSAS...AS WELL AS PORTIONS OF WESTERN AND CENTRAL NEBRASKA AND
AS A RESULT...WEAK ISENTROPIC UPGLIDE AND SATURATION ALONG THE
275-280K SURFACES PERSIST ACROSS PORTIONS OF THE REGION. THIS
ISENTROPIC UPGLIDE...WORKING IN CONCERT WITH WEAK MID LEVEL
THERMAL ADVECTION AHEAD OF THE LONGWAVE TROUGH...IS PROMOTING A
WEAK BAND OF LIGHT SNOW OVER PORTIONS OF NORTHWEST KANSAS AND
SOUTHWEST NEBRASKA...WITH FLURRY ACTIVITY NOTED ON KUEX DATA AND
OBSERVED AT KHDE WITH IN THE PAST HOUR. SHORT TERM GUIDANCE FROM
THE RAP AND NAM SUGGEST THE ISENTROPIC UPGLIDE SHOULD DIMINISH
THROUGH THE NEXT SIX HOURS OR SO BUT UNTIL THAT TIME...OCCASIONAL
FLURRY ACTIVITY CANNOT BE RULED OUT ACROSS THE WEST/NORTHWEST HALF
OF OUR CWA. WENT AHEAD AND INTRODUCED FLURRY WORDING TO THE
FORECAST FOR THESE LOCATIONS FOR TONIGHT AS A RESULT. THE
REMAINDER OF THE FORECAST REMAINS IN GREAT SHAPE...WITH ONLY SOME
MINOR TWEAKS MADE TO HOURLY TEMPERATURE...DEWPOINT...AND WIND
GRIDS TO BETTER REFLECT CURRENT OBSERVATIONS.
PREV DISCUSSION... /ISSUED 358 PM CST MON JAN 14 2013/
SHORT TERM...TONIGHT THROUGH TUESDAY. COLD AND DRY WEATHER WILL
CONTINUE WITH BELOW NORMAL TEMPERATURES...ALTHOUGH TUESDAY WILL BE
AT LEAST SOMEWHAT WARMER THAN TODAY.
TONIGHT...THE UPPER LEVEL TROUGH AXIS WILL SLIDE INTO OUR FORECAST
AREA AND SOME MID LEVEL CLOUDS ARE EXPECTED. THIS SHOULD KEEP LOW
TEMPERATURES A FEW DEGREES WARMER THAN LAST NIGHT. HOWEVER...THE
CLOUDS MAY BEGIN TO CLEAR ACROSS OUR NORTHWEST PRIOR TO SUNRISE
ALLOWING FOR GREATER RADIATIONAL COOLING. THEREFORE...EXPECT THE
COLDEST READINGS TO LIKELY RUN FROM AROUND ORD TO GOTHENBURG.
TOMORROW...THE LOW LEVEL WIND FIELD WILL BE WESTERLY ALLOWING WARMER
AIR TO SLOWLY WORK BACK INTO THE PLAINS. IN ADDITION...SUNNY TO
MOSTLY SUNNY SKIES ARE EXPECTED. THE STRIPE OF SNOW COVER ACROSS THE
CENTER OF OUR CWA WILL CONTINUE TO KEEP HIGH TEMPERATURES SEVERAL
DEGREES COOLER OVER SNOW COVERED AREAS THAN OVER SNOW FREE AREAS.
WILL CALL FOR ABOVE FREEZING HIGH TEMPERATURES OVER SNOW FREE
AREAS...WITH HIGHS A FEW DEGREES BELOW FREEZING OVER OUR SNOW
COVERED AREAS.
LONG TERM...(TUESDAY NIGHT THROUGH MONDAY)
THE MAIN STORY: A STRING OF VERY NICE/MILD DAYS BEGINS WED AS THE
CURRENT COLD SNAP EASES...GIVING US A BREAK BEFORE THE "POTENTIALLY"
COLDEST AIR SO FAR THIS SEASON EARLY NEXT WEEK.
PATTERN: THE LONG-WAVE FLOW YOU SEE WED /WRN N AMERICA RIDGE AND AN
ERN TROF/ WILL BE WITH US FOR THE NEXT 10 DAYS. THE GFS ENSEMBLE HAS
A STRONG SIGNAL FOR A +PNA PATTERN THRU THIS PERIOD...PEAKING ON THE
21ST. THIS MEANS THE ERN USA WILL BE DEALING WITH FRIGID ARCTIC COLD
DELIVERED BY A TRAIN OF ALBERTA CLIPPERS. FOR NOW NW FLOW WILL LOCK
THE ARCTIC FRONT JUST NE OF THE FCST AREA. AND WHILE WE WILL BENEFIT
FROM DOWNSLOPE WARMING IN THE WARM SECTOR OF THESE CLIPPERS...
BELIEVE WE WILL HAVE TO DEAL WITH SPELL OF BITTER ARCTIC COLD DURING
THE NEXT 10 DAYS. MODELS HAVE BEEN HINTING THAT THE WRN FRINGE OF
THIS AIR MASS BACKS INTO CNTRL PLAINS NEXT SUN-MON. WATCH THE SWD
PROGRESSION WITH EACH CLIPPER! THE GFS ENSEMBLE MEAN ALREADY HAS -1
STANDARD DEVIATION TEMPS AT H8 IN THAT TIMEFRAME AND THAT/S WITH
-15C. 00Z EC ENSEMBLE MEAN HAS -12C BUT THAT/S WITH A LOT GREATER
MEMBERSHIP AND MORE AVERAGING. THE 06Z/12Z DETERMINISTIC GFS CYCLES
HAVE -17 OR -18C WHICH WOULD SUPPORT HIGHS IN THE SINGLE DIGITS OVER
S-CNTRL NEB. THIS WITH HIGH PRES NEAR OR IN EXCESS OF 1040 MB.
A STEADY-STATE PATTERN OFFERS ABOVE AVERAGE FCST CONFIDENCE.
BOTTOM LINE...TEMPS WILL AVERAGE ABOVE NORMAL /OR MUCH ABOVE NORMAL
FOR AREAS WITH NO SNOW COVER/ THRU SAT THEN TURNING MUCH BELOW
NORMAL SUN-MON THRU THE MIDDLE OF NEXT WEEK. DRIER THAN NORMAL WITH
MOST PLACES PROBABLY NOT EVEN REGISTERING A TRACE OF PRECIP OVER THE
NEXT 10 DAYS.
HAZARDS: 1) A WARM FRONTAL PASSAGE COULD THREATEN A BIT OF LIGHT SN
OR FRZG DRIZZLE TUE NGT OVER OUR S-CNTRL NEB COUNTIES.
2) THERE IS A CHANCE OF DANGEROUSLY LOW WIND CHILLS EARLY
NEXT WEEK. TOO EARLY TO TELL ON WIND SPEEDS BUT
SOMETHING TO WATCH.
UPCOMING PCPN OPPORTUNITIES: NOTHING SUBSTANTIAL.
THE DAILY DETAILS...
ALL INITIALIZED LOW TEMPS WERE REPLACED WITH ITS BIAS CORRECTED
COUNTERPART UNLESS OTHERWISE NOTED.
TUE NGT: INCREASING CLOUDS. MILD WITH A BREEZY SW WIND SHIFTING TO
THE W. WARM FRONTAL PASSAGE. SOUNDINGS THREATEN A TOUCH OF LIGHT SN
OR FRZG DRIZZLE. IT/S NOT IN THE FCST BUT SOMETHING TO WATCH. TEMPS
WILL DROP INITIALLY WITH SUNSET THEN TEMPS HOLDING STEADY OR SLOWLY
RISING.
WED: BECOMING M/SUNNY. CLIPPER RACES ACROSS SRN CANADA. TEMPS ARE
BIAS CORRECTED MEX MOS. THE NAM HAS TOO MUCH CONTAMINATION FROM ITS
MODELED SNOW COVER. BUT DID I GO WARM ENOUGH IN THE NO/LOW SNOW
COVER AREAS? WE/LL BE STARTING FROM VERY MILD MID-UPPER 20S AND SOME
2M TEMP GUIDANCE IS SUGGESTING LOW 50S OUTSIDE AREAS WITH REMAINING
CRUSTY SNOW COVER.
THU: HIGH PRES DRIFTS THRU IN THE MRNG WITH SW WINDS DEVELOPING.
M/SUNNY. HAVE TEMPS FAIRLY CLOSE TO WED/S HIGHS. USED BIAS CORRECTED
MAV MOS AGAIN. WITH RETURN FLOW DELAYED INTO THE AFTN...FCST TEMPS
COULD END UP 2-3F TOO WARM.
FRI: ANOTHER VERY NICE DAY IN THE WARM SECTOR OF ANOTHER CLIPPER
ROTATING THRU THE GREAT LAKES. TEMPS ARE BIAS CORRECTED MEX MOS.
COULD SEE ORD AND STOCKTON/OSBORNE/BELOIT FLIRT WITH 50F!
SAT: PROBABLY ANOTHER PLEASANT DAY BUT WITH AN ARCTIC COLD FRONTAL
PASSAGE. UNCERTAINTY IN TEMPS AS MODELS STRUGGLE WITH EXACT TIMING/
LOCATION OF THE FRONT.
WIND: WE PROBABLY HAVE TO DEAL WITH A PERIOD OF BLUSTERY N WINDS
BEHIND THE FRONT. NOT SURE ON THE TIMING.
SUN-MON: AFTER COORDINATING WITH SURROUNDING OFFICES...ALL DAYTIME/
NIGHTTIME TEMPS WERE LOWERED TO THE WEIGHTED CONSENSUS OF THE 3
BEST-VERIFYING TEMP GUIDES.
SUN: COLDER BUT NOT UNBEARABLE.
SUN NGT OR MON: THE ARCTIC FLOOD-GATES OPEN WITH A BITTER 1050 MB
HIGH SLIDING DOWN THE FRONT RANGE.
MON: BITTERLY COLD AND WE NEED TO KEEP THE DOOR OPEN FOR SINGLE
DIGITS HIGH TEMPS! ESPECIALLY OVER OUR NEB COUNTIES. EVEN WITH THE
MORE CONSERVATIVE GFS AND 00Z EC...IF WE END UP CLOUDY IT WILL BE A
SLAM-DUNK. WATCH FOR LOW CLOUDS TO GET TRAPPED UNDER THE FRONTAL
INVERSION. THE 12Z EC CAME IN AND IS PROBABLY THE WORST CASE
SCENARIO...WITH -24C DOWN TO GRI AT 00Z/TUE.
EVEN THO WE/VE LOWERED TEMPS...WE STILL COULD BUST ANOTHER 5-10F TOO
HIGH.
&&
.GID WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
KS...NONE.
&&
$$
AVIATION...HEINLEIN
910PM UPDATE...BRYANT
SHORT TERM...WESELY
LONG TERM...HALBLAUB
AREA FORECAST DISCUSSION...UPDATED
NWS NORTH PLATTE NE
1119 PM CST MON JAN 14 2013
.UPDATE...
.AVIATION...
MVFR/LOCAL IFR IN SNOW HAS DEVELOPED FROM KIML TO KLBF. THIS AREA
IS DRIFTING EAST AND IS EXPECTED TO CONTINUE MOVING VERY SLOWLY
EAST OVERNIGHT.
MVFR CIGS SHOULD DEVELOP TUESDAY EVENING ACROSS NRN NEB AS AN
UPPER LEVEL DISTURBANCE DROPS SOUTH THROUGH THE NRN HIGH PLAINS.
LIGHT SNOW MAY DEVELOP IN SOME AREAS.
OTHERWISE VFR ALL AREAS OVERNIGHT AND TUESDAY.
.PREV DISCUSSION... /ISSUED 745 PM CST MON JAN 14 2013/
UPDATE...
DISCUSSION...
WE ARE FAST APPROACHING FCST LOWS ACROSS THE NORTH WHERE SKIES ARE
CLEAR. SO A NEW MIN TEMPERATURE FCST IS OUT. THE REST OF THE FCST
IS ON TRACK.
PREV DISCUSSION... /ISSUED 531 PM CST MON JAN 14 2013/
UPDATE...
AVIATION...
VFR IS EXPECTED ALL AREAS TONIGHT AND TUESDAY.
A WEAK UPPER LEVEL DISTURBANCE ACROSS SWRN NEB WILL SPREAD LIGHT
SNOW THROUGH THE EVENING HOURS. IT IS NOT CLEAR MVFR WILL COVER
THIS AREA. LOCAL MVFR COULD DEVELOP AS THIS AREA OF SNOW MOVES
THROUGH. ANOTHER AREA TO WATCH WOULD BE NORTHWEST NEBRASKA LATE
TOMORROW AFTERNOON. AN UPPER LEVEL DISTURBANCE ACROSS THE NRN HIGH
PLAINS WILL BE MOVING SOUTHEAST TOWARD NORTHWEST NEBRASKA LATE IN
THE AFTERNOON. THIS DISTURBANCE HAS THE POTENTIAL TO PRODUCE MVFR
CIGS. OTHERWISE VFR WILL PREVAIL.
PREV DISCUSSION... /ISSUED 426 PM CST MON JAN 14 2013/
UPDATE...
DISCUSSION...
QUICK UPDATE FOR SOUTHWEST NEBRASKA. THE RUC13 SHOWS AND AREA OF
LIGHT SNOW ON THE 285K INSENTROPIC SFC MOVING EAST THIS EVENING.
THE NEW FORECAST SLOWS THIS DOWN ABOUT 3 HOURS AND RAISES THE POP
TO 50 PERCENT. LESS THAN AN INCH ACCUMULATION IS EXPECTED
ALTHOUGH THE RUC SHOWS 3 INCHES. THE RUC IS OFTEN TOO WET. REST OF
THE FORECAST IS GOOD.
PREV DISCUSSION... /ISSUED 245 PM CST MON JAN 14 2013/
SYNOPSIS...
IN THE UPPER LEVELS...THE LARGE SCALE CYCLONIC FLOW CONTINUES
OVER A LARGE PART OF THE CENTRAL AND WESTERN U.S. RUNNING A 24 HOUR
LOOP OF THE IMAGERY...ONE CAN SEE THE DIGGING AND NARROWING OF THE
TROUGH. ANALYSIS OF THE 20Z SURFACE DATA REVEALED A WARM FRONT
DEVELOPING ACROSS EASTERN MONTANA AND EASTERN WYOMING.
SHORT TERM...TONIGHT THROUGH TUESDAY NIGHT.
A LOOK AT THE 280-290K LAYER INDICATES SOME WEAK ISENTROPIC LIFT
CONTINUING INTO THIS EVENING IN EXTREME SOUTHWEST NEBRASKA.
HOWEVER...VERY LITTLE MOISTURE AND ACCUMULATIONS WILL BE HALF AN
INCH OR LESS.
FOR TUESDAY...A WARM FRONT IS EXPECTED INTO WESTERN NEBRASKA BY
EARLY EVENING. AGAIN...IN THE 280-290K LAYER...ISENTROPIC UPGLIDE IS
LIKELY TO PRODUCE SOME CLOUDINESS AND POSSIBLY SOME LIGHT SNOW IN
THE EVENING AND LIGHT FREEZING DRIZZLE LATE TUESDAY NIGHT AND VERY
EARLY WEDNESDAY.
MEDIUM RANGE/EXTENDED...WEDNESDAY THROUGH SUNDAY.
DRY AND MUCH WARMER WEATHER CAN BE EXPECTED WEDNESDAY THROUGH
FRIDAY IN THE AFTERMATH OF THE WARM FRONT.
MUCH COLDER WEATHER IS EXPECTED AGAIN AS A BACK-DOOR FRONT COMES
ACROSS SATURDAY NIGHT AND SUNDAY. THE FRONT STALLS ALONG THE EASTERN
SLOPE OF THE ROCKIES AND SOUTHWEST FLOW WILL PRODUCE ISENTROPIC LIFT
AND COULD GIVE SOME POTENTIAL FOR WIDESPREAD SNOW MONDAY AS THE
SYSTEM MAKES ITS WAY BACK TO THE EAST-NORTHEAST. AT THAT RANGE...
THE UNCERTAINTY IS VERY HIGH REGARDING AMOUNTS AND INTENSITY OF
PRECIPITATION.
AVIATION...
FOR THE 18Z TAF FORECAST CYCLE...GENERAL VFR EXPECTED TODAY
ACROSS MOST AREA TERMINALS. THE EXCEPTION BEING ACROSS FAR
SOUTHWEST NEBRASKA TODAY...POSSIBLY AFFECTING THE KOGA AND KIML
TERMINALS WHERE SCATTERED LIGHT SNOW MAY BRIEFLY REDUCE VISIBILITIES
INTO MVFR. MODEL GUIDANCE HAS THE REMAINING LIGHT SNOW DISSIPATING
LATER THIS AFTERNOON...IF NOT ALREADY SO...THEREAFTER DRIER AIR
ALOFT WILL WORK BACK ACROSS THE REGION...WITH NO VISIBILITY OR
CEILING RESTRICTIONS ANTICIPATED. FOR THE OVERNIGHT...NAM SHORT
TERM GUIDANCE HINTS AT REDUCED VISIBILITY /DOWN TO 3SM/ AT KLBF
AFTER 06Z WITH THE FORMATION OF LOW FOG. FEEL THAT THE SOLUTION IS
OVERLY AMBITIOUS WITH THE REMAINING LOW LEVEL MOISTURE...SO WILL NOT
INCLUDE A MENTION OF MVFR VISIBILITY IN THE OFFICIAL TAF FORECAST
NOW. OTHERWISE BROAD SURFACE HIGH PRESSURE WILL KEEP WIND SPEEDS
RELATIVELY LIGHT AND VARIABLE FOR ALL TERMINALS.
&&
.LBF WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
SHORT TERM/EXTENDED...BROOKS
AVIATION...CDC
AREA FORECAST DISCUSSION
NWS BINGHAMTON NY
714 PM EST WED JAN 16 2013
.SYNOPSIS...
THE STORM SYSTEM THAT BROUGHT THE SNOW TO THE AREA TODAY HAS
EXITED OFF OF THE EAST COAST. A COLD FRONT WILL CROSS THE AREA ON
THURSDAY BRINGING SCATTERED SNOW SHOWERS AND DROPPING TEMPERATURES
DURING THE AFTERNOON. BRIEFLY MILDER TEMPERATURES SATURDAY...WILL
BE REPLACED BY MUCH COLDER AIR EARLY NEXT WEEK.
&&
.NEAR TERM /UNTIL 6 AM THURSDAY MORNING/...
7 PM UPDATE...
JUST MINOR TWEAKS TO HRLY T/TD GRIDS AT THIS TIME AS THEY APPEAR
TO BE RIGHT ON TARGET. SNOW HAS EXITED THE REGION TO THE EAST WITH
DRY AIR WORKING DOWN WELL INTO THE BL, LEAVING VRY LITTLE CHC FOR
LINGERING FZRA OR FZDZ. THUS POPS HV BEEN DROPPED TO ZERO UNTIL
COLD FRNT INCHES CLOSER. LIGHT SNOW IS OCCURRING ACRS SRN ONTARIO
AND CANADIAN RADARS INDICATE THIS AREA OF PCPN ABOUT READY TO
ENTER OVR LK ONTARIO. 18Z NAM AND LATEST HRRR HAS FAIRLY GOOD
HANDLE ON PCPN LOCATION AND HV USED MODEL BLENDS TO ACCNT FOR
TRENDS DRG THE OVRNGT PD.
TIMING ON FRONT BRINGS IT INTO FINGER LKS REGION BY 12Z WHICH IS
IN LINE WITH THE NAM12. SLGT CHC POPS ENTER INTO EXTRM NRN ZONES
BY 03Z AND SPREAD INTO TWIN TIERS BY 12Z. AS LK MOISTURE IS PICKED
UP, HICHC TO LKLY POPS EXPECTED ARND 12Z AS SATURATED LYR
INCREASES TO NR 800MB AND MEAN FLOW SETTLES OUT ARND 280 DEGREES.
SNOWFALL AMNTS ACRS ONEIDA CNTY THRU 12Z THURSDAY WILL BE ARND 1
INCH.
SKIES HV CLRD ACRS PORTIONS OF THE CWA AS OF 00Z AND WL DROP SOUTH
TONIGHT AS DRY AIR MVS IN BHND SYSTEM AND AHD OF APPCHG FRONTAL
BNDRY. THUS HV UPDATED SKY GRIDS TO ACCNT FOR THIS TREND AND MAY
IMPACT AMNT OF TEMP DROP WITH SNOWPACK IN PLACE ONCE AGAIN.
PREV DISCO BLO...
3 PM UPDATE...
LINGERING LIGHT PRECIP WILL MOVE OUT BY 7 PM. WITH LOW LEVEL
SATURATION NOT GOING INTO THE DENDRITE ZONE, FREEZING RAIN AND
FREEZING DRIZZLE IS POSSIBLE.
DRIER AIR WILL MOVE IN SLOWLY FROM THE WEST. THE BACK EDGE NOW
FROM FZY TO DSV. QUIET THIS EVENING BEFORE A COLD FRONT DROPS SE
THROUGH THE CWA LATE TONIGHT AND THU MORNING. SOME MOISTURE BUT
SNOW SHOWERS WILL BE LIGHT. 6 HOUR SNOWFALL AMOUNTS UNDER AN INCH.
&&
.SHORT TERM /6 AM THURSDAY MORNING THROUGH SATURDAY/...
3 PM UPDATE...
WITH THE COLD FRONT THURSDAY HIGHS WILL BE IN THE MORNING WITH
CENT NY DROPPING IN THE AFTN. LAKE EFFECT WILL KICK IN BUT SHOULD
REMAIN WEAK INTO FRIDAY. SHEAR IS HIGH. THE SATURATED LEVEL IS
ONLY TO 5K TO START THEN LIFTS TO 7 THU NGT. A SHALLOW DENDRITE
ZONE AT THE TOP OF THE SATURATED LAYER WILL ALSO LIMIT SNOWFALL
THU. THU NGT LAKE EFFECT SHOULD BE BETTER BUT NW FLOW WILL MEAN
MULTIBANDS AND NO LAKE HURON CONNECTION. COLDER WITH BETTER
MOISTURE. THE COLDER AIR BRINGS THE DENDRITE ZONE DOWN SOLIDLY IN
THE DENDRITE ZONE. STILL A LOT OF SHEAR WITH HARDLY ANY SFC TO 2K
WINDS.
FRI AFTN INTO SAT THE LOW LEVEL WINDS SHIFT TO WEST SENDING THE
LAKE EFFECT INTO JUST ONEIDA. WAA STARTS KILLING THE LAKE EFFECT
FRI NGT, BUT NOT SOON ENOUGH TO GET FRI HIGH TEMPS ABOVE FREEZING.
HIGH PRESSURE SLIDES EAST FROM THE OHIO VALLEY FRI INTO THE
CAROLINAS FRI NGT.
A WARM FRONT AHEAD OF A SFC LOW MOVING EAST IN SE CANADA WILL
BRING SNOW SHOWERS ALONG THE LAKE SHORE LATE FRI AND FRI EVE. LOW
LEVEL FLOW CONTINUES OUT OF THE W AND SW SATURDAY SO MOST OF THE
CWA WILL BE DRY. WITH 850MB TEMPS APPROACHING ZERO HIGH TEMPS WILL
RISE INTO THE U30S AND L40S.
&&
.LONG TERM /SATURDAY NIGHT THROUGH WEDNESDAY/...
230 PM WED UPDATE...
HIGH CONFIDENCE IN AN ARCTIC SHIFT TO THE WEATHER PATTERN WITH
PERHAPS THE COLDEST AIR OF THE SEASON EN ROUTE. GFS AND ECMWF
AGREE ON 1000-500MB THICKNESSES DIPPING IN THE 490S FOR AT LEAST
CENTRAL NY AND CLOSE TO IT FOR NORTHEAST PA BY 12Z TUESDAY. THIS
BEGINS WITH INITIAL MOISTURE-LIMITED COLD FRONT PASSING THROUGH
EARLY SUNDAY WITH SOME SCATTERED SNOW SHOWERS...BRINGING
TEMPERATURES BACK TO NEAR NORMAL. ARCTIC FRONT THEN DROPS THROUGH
MONDAY TO SEND TEMPERATURES WELL BELOW CLIMATOLOGY EARLY NEXT WEEK.
LAKE EFFECT DETAILS AND PRESENCE OF CLIPPER-LIKE SYSTEMS WITHIN
BRISK UPPER FLOW HAVE YET TO BE SORTED OUT...YET VERY DRY AIR MASS
OVERALL...SO FOR NOW WENT ALONG WITH HPC POPS GENERALLY IN SLIGHT
TO LOW CHANCE RANGE /POPS HIGHEST WITH ARCTIC FRONT MONDAY IN
30-50 PCT RANGE/. WITH 850MB TEMPERATURES PUSHING AROUND MINUS-20
CELSIUS BY TUESDAY...JUST ABOUT ANY PASSING CLOUD WILL AT LEAST
PRODUCE LIGHT SCATTERED FLURRIES WITH ABOUT THE SAME WATER CONTENT
AS STYROFOAM.
&&
.AVIATION /00Z THURSDAY THROUGH MONDAY/...
STORM SYSTEM IS PULLING EAST, ALLOWING FOR IMPROVING CONDITIONS
ACROSS OUR TERMINALS. RME WILL REMAIN MAINLY MVFR OVERNIGHT, WHILE
THE MAJORITY OF THE REMAINING TERMINALS REACH VFR CONDITIONS.
EARLY THURSDAY MORNING...A LAKE EFFECT SNOW PLUME WILL DROP INTO
NORTHERN NY STATE. THIS WILL BRING MVFR/IFR CONDITIONS TO
RME/SYR/ITH AFTER 9Z. THE LES WILL CONTINUE UNTIL APPROXIMATELY
16Z-18Z. WINDS WILL BE NORTHWESTERLY AT 10 KTS WITH GUSTS OF 15 TO
20 KTS.
.OUTLOOK...
THU NGT THRU FRI...MAINLY MVFR CIGS AND SOME SCT -SHSN IN CNTRL
NY...VFR AVP.
FRI NGT/SAT...MAINLY VFR.
SAT NGT THRU MON...MVFR/IFR IN SNOW SHOWERS...ESPECIALLY CNTRL NY.
&&
.BGM WATCHES/WARNINGS/ADVISORIES...
PA...NONE.
NY...NONE.
&&
$$
SYNOPSIS...MDP/PVN
NEAR TERM...PVN/TAC
SHORT TERM...TAC
LONG TERM...MDP
AVIATION...DJP
AREA FORECAST DISCUSSION
NWS NEWPORT/MOREHEAD CITY NC
730 AM EST TUE JAN 15 2013
.SYNOPSIS...
A COLD FRONT MOVING SOUTH OVER THE AREA EARLY THIS MORNING WILL
STALL OVER SOUTHERN SECTIONS THIS AFTERNOON AND EVENING. THE FRONT
WILL RETURN TO THE NORTH AS A WARM FRONT TONIGHT AND
WEDNESDAY...THEN CROSS THE AREA AS A COLD FRONT WEDNESDAY NIGHT. LOW
PRESSURE WILL PASS TO THE SOUTH OF THE AREA THURSDAY NIGHT AND
FRIDAY. HIGH PRESSURE WILL BUILD IN SATURDAY AND SUNDAY. A DRY COLD
FRONT WILL MOVE THROUGH THE AREA MONDAY.
&&
.NEAR TERM /TODAY/...
AS OF 700 AM TUESDAY...COLD FRONT HAS PUSHED TO S COAST WITH COOLER
TEMPS AND WDSPRD LOW CLOUDS SPREADING OVER ALL LAND AREAS. LATEST
RUC13 AND HRRR HAVE BEST HANDLE ON FRONTAL POSITION AND HAVE UPDATED
WITH BLEND. 3 HRLY PRES RISES HAVE DIMINISHED AND EXPECT FRONT TO
STALL ALONG S COAST REST OF DAY. THIS WILL ALLOW LOW CLOUDS TO LIFT
OVER SRN SECTIONS AND TEMPS TO WARM INTO 60S...WHILE CLOUDS HOLD NRN
2/3 OF AREA WITH TEMPS HOLDING IN 50S.
/PREVIOUS DISCUSSION/
AS OF 345 AM TUESDAY...COLD FRONT IS BACKDOORING ACROSS AREA EARLY
THIS MORNING WITH WIDESPREAD LOW CLOUDINESS DEVELOPING AS LOW LVL
WINDS BECOME NRLY. MODELS IN GENERAL AGREEMENT ON FRONT STALLING
NEAR HAT-EWN-DPL LINE THIS MORNING AND REMAINING NEARLY STNRY
THROUGH AFTN. MAIN THREAT OF PCPN WILL BE OVER NRN SECTIONS WITH
BETTER ISENTROPIC LIFT WHILE SRN COASTAL SECTIONS WILL SEE ISOLATED
SHOWER THREAT. WILL CONTINUE POP RANGE FROM 20 SOUTH TO NEAR 40-50
NORTH. TEMP FCST A CHALLENGE WITH BNDRY STALLED OVER AREA AND
PERSISTENT LOW CLOUDS LIMITING HEATING OVER NRN HALF OF AREA. WENT
WITH BLEND OF PREVIOUS FCST AND LATEST MOS BLEND...RESULTING IN HIGH
TEMPS RANGING FROM LOWER 50S ON NRN OBX TO NEAR 70 SRN-MOST
SECTIONS.
&&
.SHORT TERM /TONIGHT/...
AS OF 345 AM TUESDAY...SFC FRONT EXPECTED TO PUSH S OVER SRN
SECTIONS EARLY THIS EVENING...THEN RETURN N AS A WARM FRONT
OVERNIGHT AS LOW PRES DEVELOPES TO THE WEST. MODELS CONTINUE TO
INDICATE MAIN PCPN THREAT REMAINING W AND N OF AREA...BUT DO
INDICATE SOME LIGHT QPF PSBL MOST OF AREA WITH BNDRY RETURNING
N...THUS KEPT LOW CHC POPS..20 S/30 N...OVER AREA. PROBLEMATIC TEMP
FCST FOR THIS PERIOD AS WELL DUE TO BNDRY. MIN TEMPS WILL LIKELY BE
DURING EVENING HOURS OVER SRN SECTIONS WITH INCREASING TEMPS
EXPECTED OVERNIGHT AS WARM FRONT LIFTS N. LEANED TO COOLER NAM MOS
WHICH WAS GENERALLY IN LINE WITH PREVIOUS FCST.
&&
.LONG TERM /WEDNESDAY THROUGH MONDAY/...
AS OF 315 AM TUE...NO SIGNIFICANT CHANGES NEEDED TO ONGOING
FORECAST AT THIS TIME. CONTINUED TO RELY HEAVILY ON THE ECMWF AND HPC
THROUGH THE LONG TERM AS IT HAS BEEN THE MOST CONSISTENT.
FRONTAL BOUNDARY WILL REMAINED STALLED JUST TO THE W OF THE CWA
WED. EASTERN NC WILL REMAIN IN THE WARM SECTOR AS MOIST S/SWLY
FLOW CONTINUES RESULTING IN ANOTHER DAY OF ABOVE NORMAL
TEMPERATURES GENERALLY IN THE LOWER 70S IN THE SW CWA AND MID TO
UPPER 60S ELSEWHERE. DEEPEST MOISTURE AND BEST SUPPORT REMAINS TO THE
W/NW...SO WILL CONTINUE TO CAP POPS AT CHANCE FOR THE INLAND
COUNTIES. THE COLD FRONT WILL FINALLY MOVE THROUGH THE AREA WED
NIGHT AS THE LOW PUSHES OFF THE MID-ATLANTIC COAST. BEST MOISTURE
AND FORCING WILL REMAIN N OF THE AREA WED NIGHT AND NOT EXPECTING
A SIGNIFICANT AMOUNT OF QPF WITH LESS THAN A QUARTER INCH
EXPECTED.
A MUCH COLDER AIRMASS WILL BE IN PLACE ACROSS THE REGION THU WITH
LOW LEVEL THICKNESSES AROUND 40M LOWER ALLOWING FOR HIGHS 10-15
DEGREES COOLER THAN WED WITH HIGHS IN THE 50S. EXPECT DRY CONDITIONS
WITH SHORTWAVE RIDGING BUILDING ALOFT. WILL BE WATCHING THE
PROGRESSION OF THE LOW PRES SYSTEM ACROSS TEXAS LIFT ACROSS THE DEEP
SOUTH AND OFF THE NC/SC COAST THU NIGHT AND FRI. MODELS NOT IN BEST
AGREEMENT WITH THE TRACK AND INTENSITY OF THIS LOW WHICH WILL
ULTIMATELY DETERMINE THE AMOUNT OF PCPN ACROSS THE REGION. CONTINUE
TO SIDE WITH THE ECMWF WHICH IS THE WEAKER AND MORE OFFSHORE
SOLUTION. WILL CONTINUE HIGH CHANCE TO LIKELY POPS THU NIGHT AS
SHORTWAVE MOVES THROUGH.
COLD HIGH PRES WILL BE BUILDING IN FROM THE PLAIN STATES AND PCPN
MAY TRANSITION TO A RAIN/SNOW MIX AS THE PCPN WINDS DOWN THU NIGHT
BUT WITH THE VERY WARM ANTECEDENT CONDITIONS WE`VE HAD THIS PAST
WEEK DO NOT THINK THERE WILL BE ANY IMPACTS. MORE THAN LIKELY IT
WILL BE A TYPICAL CASE OF COLD AIR CHASING THE MOISTURE. SLOWER
AND MORE AMPLIFIED MODEL SOLUTIONS CONTINUE PCPN INTO EARLY FRI
BUT AM FOLLOWING THE MORE PROGRESSIVE ECMWF AT THIS TIME. UPPER
TROUGHING CONTINUES ACROSS THE EASTERN CONUS OVER THE WEEKEND.
TEMPS EXPECTED TO BE A LITTLE BELOW NORMAL IN THE M/U40S
FRI...THEN THICKNESSES RECOVER OVER THE WEEKEND WITH HIGHS IN THE
M/U50S. A DRY COLD FRONT IS THEN PROGGED TO PUSH THROUGH THE
REGION SUN NIGHT WITH COLD HIGH PRES BUILDING IN FROM THE N MONDAY
BRINGING HIGHS IN THE L/M50.
&&
.AVIATION /12Z TUESDAY THROUGH SATURDAY/...
SHORT TERM /THROUGH 12Z WEDNESDAY/...
AS OF 630 AM TUESDAY...COLD FRONT HAS PUSHED S OF ALL TAF
SITES...WITH WDSPRD IFR CIGS DEVELOPING IN COOL SECTOR. FRONT WILL
STALL OVER SRN SECTIONS TODAY...WITH CIGS EXPECTED TO LIFT TO MVFR
WITH PERIOD OF VFR PSBL FOR KOAJ. IFR WILL RETURN THIS EVENING...BUT
SOME IMPROVE EXPECTED OVERNIGHT WITH FRONT LIFTING N AGAIN. IFR
LIKELY AT KPGV ENTIRE TAF PERIOD.
LONG TERM /WEDNESDAY THROUGH SATURDAY/...
AS OF 315 AM TUE...SUB-VFR CONDITIONS WILL BE POSSIBLE
WED...MAINLY FOR PGV/ISO...AS FRONTAL BOUNDARY REMAINS STALLED
JUST INLAND. THE COLD FRONT WILL MOVE THROUGH THE TERMINALS WED
NIGHT WITH SCT SHOWERS AND NLY WINDS DEVELOPING BEHIND IT. RAIN
WILL RETURN THU NIGHT WITH PERIODS OF SUB-VFR LIKELY. PREDOMINATE
VFR CONDITIONS SHOULD RETURN FRI AND SAT AS HIGH PRESSURE BUILDS
OVER THE AREA.
&&
.MARINE...
SHORT TERM /THROUGH TONIGHT/...
AS OF 700 AM TUESDAY...COLD FRONT HAS PUSHED TO SRN WATERS EARLY
THIS MORNING WITH NE SURGE OF 15-20 KTS OVER PORTIONS OF CENTRAL
WATERS AND PAMLICO SOUND. FRONT EXPECTED TO STALL OVER SRN WATERS
REST OF DAY WITH WINDS DECREASING TO LESS THAN 15 KT. FRONT WILL
RETURN N AS WARM FRONT OVERNIGHT...WITH SW WINDS INCRREASING TO
15-20 KTS LATE TONIGHT OVER SRN AND CENTRAL WATERS AS LOW PRES
DEVELOPES TO W.
WW3 REMAINS CONSISTENT WITH PREVIOUS FCST WITH SEAS MAINLY 2-4 FT.
LONG TERM /WEDNESDAY THROUGH SATURDAY/...
AS OF 315 AM TUE...A COLD FRONT WILL REMAIN JUST INLAND
WED...RESULTING IN MODERATE SWLY FLOW ACROSS THE WATERS. MARGINAL
SCA CONDITIONS POSSIBLE FOR THE CENTRAL WATERS WED AFTERNOON...BUT
THINK IT COULD BE DIFFICULT FOR SW WINDS TO MIX WELL OVER THE COOLER
WATERS. AT THIS TIME STILL EXPECT WINDS 10-20KT AND SEAS 3-5FT. THE
FRONT WILL MOVE THROUGH THE WATERS WED NIGHT WITH NLY WINDS 10-15KT
DEVELOPING BEHIND IT. UNCERTAINTY STILL REMAINS FOR THU AND FRI WITH
DEVELOPMENT OF LOW PRESSURE SYSTEM TO THE SOUTH. NO SIG CHANGES MADE
TO PREVIOUS FORECAST AT THIS TIME...CONTINUED TO TREND WITH HPC AND
ECMWF. EXPECT NLY WINDS TO INCREASE THU NIGHT WITH SEAS BUILDING
INTO FRI. THOUGH UNCERTAINTY REMAINS...LIKELY TO SEE SCA CONDITIONS
DEVELOP THU NIGHT AND CONTINUE INTO FRI. CAPPED WINDS AT 25KT AND
SEAS AT 4-7FT. HIGH PRESSURE WILL BUILD EASTWARD ACROSS THE AREA FOR
FRI AND SAT. NE WINDS WILL SLOWLY SUBSIDE FRI BECOMING LIGHT SAT.
&&
.MHX WATCHES/WARNINGS/ADVISORIES...
NC...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...JME
NEAR TERM...JBM
SHORT TERM...JBM
LONG TERM...SK/CQD
AVIATION...JBM/CQD
MARINE...JBM/CQD
AREA FORECAST DISCUSSION
NWS WILMINGTON NC
716 AM EST TUE JAN 15 2013
.SYNOPSIS...
ATLANTIC HIGH PRESSURE WILL PRODUCE UNSEASONABLY MILD CONDITIONS
INTO MID-WEEK. A COLD FRONT WILL MOVE SLOWLY THROUGH THE AREA LATE
WEDNESDAY. WEAK GULF COAST LOW PRESSURE WILL BRING A CHANCE OF
RAIN TO THE REGION THURSDAY NIGHT INTO FRIDAY. HIGH PRESSURE WILL
BUILD IN BEHIND THE COLD FRONT FOR THE WEEKEND. A DRY COLD FRONT
WILL MOVE ACROSS THE SOUTHEAST SUNDAY NIGHT.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 630 AM TUESDAY...A SNAKING COLD FRONT LYING NE-SW ACROSS
THE CAROLINAS WILL BASICALLY DROP TO THIS GENERAL VICINITY TODAY
BEFORE BECOMING ALIGNED WITH THE FLOW ALOFT. LOOKING AT 11-3.9
MICRON SAT IMAGERY TRENDS...INDICATES THIS FRONT CONTINUES TO MAKE
SOME PROGRESS TO THE SOUTHEAST. THIS WILL IMMEDIATELY HAVE
IMPLICATIONS TO THE CURRENT FORECAST IF THIS MOVEMENT DOES NOT
SLOW AND STALL.
THE WESTERN ATLANTIC RIDGING BOTH AT THE SFC AND ALOFT...WILL
CONTINUE TO PARTIALLY EXTEND ACROSS THE FORECAST AREA. MODELS QUITE
SIMILAR WITH THE STALLED COLD FRONT MEANDERING JUST WEST THROUGH
NORTH OF THE FORECAST AREA INTO TONIGHT. LATEST HRRR AND TO AN
EXTENT THE NAM/GFS...INDICATE THE FRONT TO REACH THE NORTHERN
PORTIONS OF THE ILM CWA TODAY BEFORE BACKING TO THE NORTH LATER
TONIGHT. WILL INDICATE ITS PARTIAL PASSAGE WITH A REFLECTION IN
THE WIND FIELD AND LOWERING OF THE TEMPS. WITH THE MAJORITY OF
THE PCPN ASSOCIATED WITH THIS FRONTAL SYSTEM OCCURRING AFTER ITS
PASSAGE AND NOT AHEAD OF IT...HAVE KEPT POPS TO A MINIMUM WITH
ONLY A SLIGHT CHANCE FOR RW-. WITH INSTABILITY LACKING IE. NEARLY
NONEXISTENT CAPE AND POSITIVE LI VALUES...THUNDER WILL REMAIN OUT
OF THE NEAR TERM FORECAST. FOR OVERALL TEMPS...HAVE STAYED WITH
THE HIGHER MODEL MOS GUIDANCE...WITH AN ADDITIONAL COUPLE OF
DEGREES ADDED ON ACROSS THE SOUTHERN PORTIONS OF THE ILM CWA.
&&
.SHORT TERM /WEDNESDAY THROUGH THURSDAY NIGHT/...
AS OF 230 AM TUESDAY...COLD FRONT WEST OF THE AREA AT THE START
OF THE PERIOD SLOWLY MOVES OFFSHORE LATE WED NIGHT. THIS ALLOWS
ONE LAST DAY OF TEMPERATURES WELL ABOVE CLIMO. INCREASING CLOUDS
AND ISOLATED AFTERNOON INSTABILITY SHOWERS MAY HOLD TEMPS DOWN A
LITTLE BIT...ESPECIALLY INLAND...BUT WIDESPREAD LOW 70S ARE STILL
ANTICIPATED. LOWS CONTINUE TO RUN WELL ABOVE CLIMO...LOWER 50S
ACROSS MUCH OF THE AREA.
FORECAST COMPLEXITY INCREASES WED NIGHT THROUGH THU NIGHT WITH A
SOUTHERN STREAM SYSTEM EXITING THE SOUTHWEST WED NIGHT AND MOVING
ACROSS THE GULF COAST THU. TIMING AND TRACK OF THE 5H SHORTWAVE
TROUGH AND RESULTING SURFACE WAVE REMAIN IN QUESTION. TREND IN
GUIDANCE HAS BEEN SHOWING THE SOUTHERN STREAM WAVE NEARLY CLOSED OFF
AS IT EMERGES FROM THE SOUTHWEST THEN OPENING UP BY THE TIME IT
MOVES INTO THE SOUTHEAST AND OFF THE EAST COAST. THIS LIMITS
CYCLOGENESIS ALONG THE BOUNDARY STALLED OFF THE COAST...KEEPING
SURFACE WAVE LITTLE MORE THAN WEAK LOW AT BEST. GUIDANCE IN FAIRLY
GOOD AGREEMENT TRACKING THE 5H FEATURE OVER OR JUST SOUTH OF THE ILM
AREA...RESULTING IN AN INCREASE IN ISENTROPIC LIFT LATER THU AND THU
NIGHT. PLENTY OF DEEP MOISTURE IN PLACE WITH FORECAST SOUNDINGS
BECOMING NEARLY SATURATED THROUGH 400MB THU NIGHT. ABUNDANT DEEP
MOISTURE AND STRENGTHENING ISENTROPIC LIFT SHOULD PRODUCE A DECENT
RAINFALL EVENT AS THE PERIOD ENDS. IS WORTH NOTING THAT THE CANADIAN
CONTINUES TO BE A SLOW OUTLIER...BY ABOUT 12 HOURS OR SO. THE
CANADIAN KEEPS THE SHORTWAVE...ALONG WITH THE LARGER SCALE FLOW...A
LITTLE MORE AMPLIFIED THAN THE NAM/GFS/ECMWF SOLUTIONS AND IS SLOWER
TO OPEN UP THE 5H WAVE. AS A RESULT IT HAS PRECIP DEVELOPING LATE
THU NIGHT AND CONTINUING BEYOND THE SCOPE OF THE PERIOD. AT THIS
POINT PLAN TO IGNORE THE SLOWER CANADIAN GIVEN THE RELATIVE
AGREEMENT BETWEEN THE OTHER GUIDANCE AND THE LACK OF ANY SLOWER
SOLUTION WITHIN THE GFS ENSEMBLES.
TEMP FORECAST THU AND THU NIGHT IS DIFFICULT. THERE IS LIKELY TO BE
A VERY NARROW BUT SIGNIFICANT TEMPERATURE GRADIENT ACROSS THE AREA
FOR MUCH OF THU/THU NIGHT. IN FACT MOS NUMBERS VARY BY 10 DEGREE OR
MORE ACROSS THE REGION. FOR NOW FAVORING THE COOLER GFS/ECMWF
SOLUTION OVER THE NAM. RETURN FLOW DEVELOPS EARLIER IN THE NAM WHICH
RESULTS IN FRONT OFF THE COAST LIFTING BACK NORTH AS WARM FRONT.
THIS IS A SHIFT FROM LAST NIGHTS NAM RUN AND AT ODDS WITH
GFS/ECMWF/HPC SOLUTIONS AND IS BEING DISCOUNTED AT THIS POINT. TEMPS
NEAR CLIMO THU WITH INCREASING CLOUD COVER AND THREAT OF RAIN.
ARRIVAL OF COLD AIR WILL DETERMINE HOW LOW TEMPS DROP BEFORE END OF
THU NIGHT...BUT AT THIS POINT LOWS A FEW DEGREES ABOVE CLIMO SEEM IN
ORDER.
&&
.LONG TERM /FRIDAY THROUGH MONDAY/...
AS OF 230 AM TUESDAY...WEAKENING SHORTWAVE AND SURFACE LOW WILL
BE EXITING THE REGION FRI MORNING. LIGHT PRECIP MAY LINGER INTO
LATE MORNING...ESPECIALLY ALONG THE COAST...BUT IT APPEARS
MAJORITY OF THE DAY WILL BE DRY WITH DECREASING CLOUDS IN THE
AFTERNOON. MID LEVEL FLOW IN THE WAKE OF THE SHORTWAVE TROUGH WILL
BE WEST-SOUTHWEST AND WEAKLY DIVERGENT. ALTHOUGH THERE WILL BE A
LACK OF MOISTURE TO THE WEST BOTH GFS AND ECMWF HAVE SOMETHING
BREWING OFF THE SOUTHEAST COAST FOR THE WEEKEND. DIFFERENCES WITH
RESPECT TO HOW FAR OFF THE COAST THE FEATURE DEVELOPS AND HOW
STRONG IT BECOMES. GIVEN LOW CONFIDENCE AND LIMITED AGREEMENT WILL
HOLD ONTO SILENT POP FOR WATERS OVER WEEKEND BUT NOT CARRY ANY POP
FOR LAND AREAS. DRY COLD FRONT CROSSES THE AREA SUN NIGHT WITH
STRONG COLD ADVECTION DEVELOPING BY MON. TEMPS NEAR CLIMO THROUGH
THE WEEKEND FALL BELOW CLIMO MON/MON NIGHT WITH THE ARRIVAL OF
COLDER HIGH PRESSURE FOR THE START OF THE WORK WEEK.
&&
.AVIATION /12Z TUESDAY THROUGH SATURDAY/...
AS OF 12Z...IFR/LIFR VSBYS ARE BEING REPORTED ACROSS THE CWA THIS
MORNING. PATCHES OF DENSE FOG MAY LINGER OVER THE COASTAL TERMINALS
THROUGH MID-MORNING...WITH CONTINUED PERIODS OF IFR/LIFR VSBYS.
LATEST SURFACE ANALYSIS SHOWS A SLOW-MOVING COLD FRONT DRAPED ACROSS
NORTH CAROLINA HAS REACHED OUR NORTHERN COUNTIES...AS KLBT IS NOW
REPORTING NORTH WINDS.
EXPECT PARTLY TO MOSTLY CLOUDY CONDITIONS TODAY...WITH VFR CIGS
DEVELOPING THIS AFTERNOON AT KLBT/KFLO. SOUTHWEST WINDS AOB 10 KNOTS
SHOULD PREVAIL THROUGH THE TAF PERIOD...EXCEPT AT KLBT WHERE THE
WINDS HAVE BECOME NORTHERLY DUE TO FROPA. ANOTHER FOG/STRATUS EVENT
APPEARS LIKELY ACROSS THE REGION AFTER MIDNIGHT WITH ABUNDANT
LOW-LEVEL MOISTURE IN PLACE. FAVORING MORE STRATUS AT THIS POINT AS
THE PRESSURE GRADIENT IS EXPECTED TO TIGHTEN OVERNIGHT...WHICH WILL
INCREASE LOW-LEVEL WINDS AND LIKELY PREVENT VSBYS FROM DROPPING AS
LOW AS TODAY. IFR CONDITIONS ARE CERTAINLY POSSIBLE AFTER 06Z WED...
BUT WENT WITH LOW MVFR FOR THIS TAF CYCLE.
EXTENDED OUTLOOK...MORNING FOG/STRATUS LIKELY AT ALL TERMINALS
WEDNESDAY WITH A SLIGHT CHANCE OF SHOWERS WEDNESDAY AFTERNOON. RAIN
LIKELY THURSDAY INTO EARLY FRIDAY. VFR DEVELOPING SATURDAY.
&&
.MARINE...
NEAR TERM /THROUGH TONIGHT/...
AS OF 630 AM TUESDAY...THE WESTERN ATLANTIC RIDGING WILL CONTINUE
TO DOMINATE THE LOCAL WATERS...PROVIDING S-SW WIND DIRECTIONS.
RELAXED SFC PG WILL TIGHTEN-SOME AS THE STALLED FRONT ACROSS THE
INLAND CAROLINAS SNAKES AND MAKES ITS CLOSEST APPROACH. SPEEDS
GENERALLY 10 KT OR LESS TODAY...INCREASING TO 10-15 KT TONIGHT.
WHERE 60+ SSTS RESIDE...WIND SPEEDS WILL BE A SOLID 15 KT.
SIGNIFICANT SEAS WILL CONTINUE TO BE DOMINATED BY A 2 TO 3 FOOT
EASTERLY SWELL AT 11-13 SECOND PERIODS. WIND DRIVEN WAVES WILL ADD
AT LEAST A FOOT TO THE OVERALL SIGNIFICANT SEAS TONIGHT...WITH 3 TO
4 FT COMMON ACROSS THE LOCAL WATERS. WITH SSTS HAVING INCREASED BY
SEVERAL DEGREES TO BETWEEN 55 AND 60 DEGREES AND NO APPRECIABLE
CHANGE WITH SFC DEWPOINTS OVER THE WATERS...SEA FOG WILL BECOME
MORE PATCHY IN COVERAGE.
SHORT TERM /WEDNESDAY THROUGH THURSDAY NIGHT/...
AS OF 230 AM TUESDAY...SOUTHERLY FLOW INCREASES TO A SOLID 15 KT
LATER WED BEFORE FRONT PUSHES OFF THE COAST WED NIGHT AND OFFSHORE
FLOW DEVELOPS. LIMITED COLD ADVECTION IN THE WAKE OF THE FRONT KEEPS
WINDS UNDER 15 KT INTO MIDDAY THU. LATE THU AND THU NIGHT TIGHTENING
GRADIENT AS WEAK LOW PASSES EAST OF THE WATERS WILL SEE NORTHEAST
FLOW APPROACH THEN EXCEED 20 KT. HEADLINES SEEM LIKELY AS THE PERIOD
ENDS...BUT DIFFICULT TO DETERMINE IF IT WILL BE SCEC OR SCA.
TRAJECTORY OF STRONG WINDS WILL DETERMINE WHETHER OR NOT 6 FT AND
HIGHER SEAS DEVELOP WITHIN 20 NM...MAINLY EAST OF CAPE FEAR AND CAPE
ROMAIN.
LONG TERM /FRIDAY THROUGH SATURDAY/...
AS OF 230 AM TUESDAY...PINCHED GRADIENT LINGERS FRI WITH NORTHEAST
FLOW 20 TO 25 KT CONTINUING INTO THE AFTERNOON. GRADIENT STARTS TO
RELAX AS SURFACE RIDGE AXIS MOVES CLOSER...BUT NORTHEAST FLOW
REMAINS 15 TO 20 KT INTO SAT. GRADIENT WEAKENS FURTHER ON SAT AS
SURFACE HIGH SETTLES SOUTH WITH SPEEDS DROPPING CLOSE TO 10 KT BY
AFTERNOON AS WINDS START TO BACK. STRONG NORTHEAST FLOW WILL CREATE
WIDE RANGE OF SEAS. ON FRI SEAS RUN 1 FT OR LESS OFF WESTERN
BRUNSWICK COAST WHILE WELL EAST OF CAPE FEAR AND CAPE ROMAIN SEAS
WILL APPROACH 10 FT. REDUCTION IN WINDS FRI NIGHT AND SAT WILL LEAD
TO A REDUCTION IN SEAS...2 TO 5 FT.
&&
.ILM WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
NC...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...III
NEAR TERM...DCH
SHORT TERM...III
LONG TERM...III
AVIATION...BJR
AREA FORECAST DISCUSSION
NWS BISMARCK ND
344 PM CST TUE JAN 15 2013
.SHORT TERM...TONIGHT THROUGH WEDNESDAY NIGHT...
THE MAIN HIGHLIGHT FOR THE SHORT TERM IS THE LATEST ROUND OF LIGHT
SNOW AND DIAGNOSING THE SEVERITY OF BLOWING SNOW.
LIGHT SNOW CONTINUES TO SPREAD SOUTHEAST ACROSS PORTIONS OF WESTERN
AND CENTRAL NORTH DAKOTA THIS AFTERNOON. LATEST OBS HAVE SHOWN
REDUCED VISIBILITY OF AROUND 1 MILE IN LIGHT SNOW...WITH INCREASING
WESTERLY WINDS ACROSS THE WEST. EVEN THOUGH REDUCED VISIBILITIES
HAVE BEEN OBSERVED ACROSS PORTIONS OF THE WEST...THE MAIN AREA OF
LIGHT SNOW WILL NOT COINCIDE WITH THE STRONGEST FORECAST WINDS
THROUGH EARLY TONIGHT. IN ADDITION...MILD TEMPERATURES AND SOME
DRIZZLE THAT OCCURRED LATE THIS MORNING...WILL HELP LIMIT THE
SEVERITY OF BLOWING SNOW...KEEPING VISIBILITIES ABOVE ADVISORY
CRITERIA. WILL CONTINUE THE TRAIN OF THOUGHT FROM PREVIOUS
SHIFTS...SINCE CONDITIONS DO NOT WARRANT AN ISSUANCE OF AN ADVISORY.
THE 12Z NAM AND LATEST RAP RUNS HAVE INITIALIZED WELL WHEN COMPARED
TO CONDITIONS AT 20Z. THEY BOTH CAPTURE THE TIMING OF THE CURRENT
ONSLAUGHT OF LIGHT SNOW OVER WESTERN AND CENTRAL NORTH DAKOTA. HAVE
OPTED TO USE A BLEND OF BOTH FOR POPS AND QPF. IN REGARDS TO
PRECIPITATION TYPE...MODEL SOUNDINGS SHOW A SHALLOW WARM LAYER ALOFT
LATER TONIGHT WHICH WILL SUPPORT THE POSSIBILITY OF SLEET AT TIMES ACROSS
THE WEST AND PORTIONS OF CENTRAL NORTH DAKOTA.
ANOTHER IMPULSE WILL ENTER NORTH CENTRAL NORTH DAKOTA MID MORNING
TOMORROW ALONG THE BAROCLINIC ZONE THAT HAS SET UP FROM THE
NORTHWEST TO SOUTHEAST TODAY...GENERATING ANOTHER ROUND OF
PRECIPITATION FOR PORTIONS OF CENTRAL NORTH DAKOTA TOMORROW.
PRECIPITATION TYPE WILL BE IN THE FORM OF LIGHT SNOW AS TEMPERATURES
WILL BE BELOW FREEZING. ONLY LIGHT ACCUMULATIONS UNDER AN INCH ARE
EXPECTED FROM ALONG THE INTERNATIONAL BORDER SOUTHEAST THROUGH THE
JAMES RIVER VALLEY.
.LONG TERM...THURSDAY THROUGH TUESDAY...
THE HIGHLIGHT OF THE EXTENDED FORECAST CONTINUES TO BE A POTENTIAL
ARCTIC OUTBREAK THIS WEEKEND INTO NEXT WEEK.
PRIOR THE POTENTIAL ARCTIC SURGE...WESTERN AND CENTRAL NORTH DAKOTA
WILL STRADDLE THE LOW LEVEL BAROCLINIC ZONE UNDER THE POLAR JET AXIS
ALOFT. THIS IS EXPECTED TO RESULT IN A LARGE TEMPERATURE
GRADIENT...ESPECIALLY ON THURSDAY WITH HIGHS IN THE 30S SOUTHWEST TO
THE SINGLE DIGITS ACROSS THE TURTLE MOUNTAINS. THERE IS A CHANCE OF
LIGHT SNOW...WITH TOTAL ACCUMULATIONS OF ONE TO TWO INCHES THURSDAY
NIGHT INTO FRIDAY FOR THE NORTH CENTRAL AND JAMES RIVER VALLEY AS
MULTIPLE IMPULSES EMBEDDED IN FAST...CYCLONIC FLOW ALOFT INTERACT
WITH THE AFOREMENTIONED LOW LEVEL BAROCLINICITY.
THEREAFTER...A VERY STRONG COLD FRONT IS FORECAST TO PROPAGATE
THROUGH WESTERN AND CENTRAL NORTH DAKOTA ON SATURDAY...MARKING THE
BEGINNING OF A POTENTIAL ARCTIC OUTBREAK CONTINUING POSSIBLY INTO
TUESDAY. THE OVERALL 12 UTC GUIDANCE SUITE IS IN GOOD AGREEMENT IN
THE DEVELOPMENT OF A HIGH AMPLITUDE UPPER LEVEL RIDGE ALONG THE
PACIFIC COAST AND INTO THE ARCTIC THROUGH THE WEEKEND AND INTO NEXT
WEEK...WHICH SHOULD ALLOW VERY COLD ARCTIC AIR TO BE TRANSPORTED
SOUTH UNDER DEEP CYCLONIC FLOW ALOFT. THE COLDEST TIMEFRAME APPEARS
TO BE SUNDAY THROUGH MONDAY NIGHT AS A NEAR 1050 MB SURFACE HIGH ON
THE DETERMINISTIC MODELS IMPACTS THE AREA. GIVEN GOOD
AGREEMENT...WILL UTILIZE A BLEND OF THE GUIDANCE...WHICH RESULTS IN
WIDESPREAD LOWS SUNDAY AND MONDAY NIGHTS OF -15 TO -25 WITH SUB-ZERO
DAYTIME HIGHS ON MONDAY. WIND CHILL TEMPERATURES COLDER THAN -40 ARE
NOT OUT OF THE QUESTION. SHOULD TRENDS CONTINUE...A WIND CHILL WATCH
MAY BE NECESSARY LATER THIS WEEK.
&&
.AVIATION...
AS OF 2130 UTC...A WARM FRONT HAD ALREADY PASSED THROUGH KISN AND
KDIK...AND WAS APPROACHING THE KMOT AND KBIS TERMINALS. A BRIEF
PERIOD OF FREEZING DRIZZLE HAS BEEN OBSERVED IN THE IMMEDIATE VICINITY
OF THE FRONT THIS AFTERNOON...WITH A BAND OF LIGHT TO MODERATE
SNOWFALL IN TRAIL. IFR/MVFR CONDITIONS IN STRATUS AND SNOW ARE
EXPECTED AT ALL TERMINALS THROUGH THE AFTERNOON AND EVENING.
WESTERLY WIND GUSTS OF 25-35 KTS BEHIND THE FRONT MAY CREATE SOME
DRIFTING SNOW. HOWEVER...ABOVE FREEZING TEMPERATURES BEHIND THE
FRONT WILL CRUST THE SNOW AND LIMIT ITS OVERALL LOFTING.
&&
.BIS WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...LTH
LONG TERM/AVIATION...PJA
AREA FORECAST DISCUSSION
NWS BISMARCK ND
110 PM CST TUE JAN 15 2013
.DISCUSSION...
LIGHT SNOW HAS BEGUN TO SPREAD EAST OUT OF EASTERN MONTANA INTO
PORTIONS OF THE WEST EARLY THIS AFTERNOON. FOR A BRIEF
PERIOD...THERE WERE SOME REPORTS OF LIGHT FREEZING DRIZZLE OUT
AHEAD OF THE MAIN AREA OF PRECIPITATION. HOWEVER...AS THE
ENVIRONMENT HAS BEGUN TO SATURATE THE LIGHT FREEZING DRIZZLE HAS
QUICKLY CHANGED OVER TO LIGHT SNOW. AS A RESULT...DECIDED NOT
MENTION FREEZING DRIZZLE IN GRIDS.
LATEST RUNS OF THE RAP AND NAM HAVE SLOWED DOWN AND LESSENED THE
INTENSITY OF THE LIGHT SNOW ACROSS THE AREA...WHICH AGREES WITH
CURRENT TRENDS AND OBS. HAVE MADE ADJUSTMENTS TO POPS/QPF/WX GRIDS
TO REFLECT THIS. OTHERWISE...MADE COSMETIC ADJUSTMENTS TO ALL
OTHER GRIDS.
&&
.AVIATION...
AS OF 19 UTC...IFR/MVFR STRATUS WAS IMPACTING
KISN...KMOT...KDIK AND KBIS AND WILL REMAIN IN PLACE THROUGH 03-06
UTC TONIGHT. THIS DECK IS EXPECTED TO REACH KJMS BETWEEN 19-20 UTC
AND HOLD THROUGH THE 12 UTC TAF CYCLE. A WARM FRONT IS ALSO FORECAST
TO MOVE THROUGH THE AREA THIS AFTERNOON...WITH WITH AREAS OF LIGHT
SNOW ACCOMPANYING IT...WITH PATCHY FREEZING DRIZZLE IN THE IMMEDIATE
VICINITY OF THE FRONT. WESTERLY WINDS GUSTING BETWEEN 25-35 KTS
BEHIND THE FRONT WILL CREATE AREAS OF BLOWING SNOW.
&&
.BIS WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
DISCUSSION...HUBER
AVIATION...AYD
AREA FORECAST DISCUSSION...UPDATED
NWS GRAND FORKS ND
1037 AM CST TUE JAN 15 2013
.DISCUSSION...CLIPPER SYSTEM WILL CONTINUE TO APPROACH THE REGION
TODAY WITH THE MAIN IMPACTS HOLDING OFF UNTIL THE OVERNIGHT HOURS.
A BAND OF WARM AIR ADVECTION SNOWFALL WILL MOVE INTO THE NE FA BY
LATE AFTERNOON...AND THROUGH THE REGION THIS EVENING. SNOWFALL
AMOUNTS LIKELY LESS THAN AN INCH. A BIT MORE SNOWFALL...AN INCH
OR TWO...POSSIBLE ACROSS THE NE FA CLOSER TO THE MAIN UPPER WAVE
AND STRONG UPPER JET. THIS IS ALL IN LINE WITH THE PREVIOUS
FORECAST...BUT DID INCREASE POPS TO CATEGORICAL ALONG AND NORTH OF
A COOPERSTOWN TO PARK RAPIDS LINE GIVEN UPSTREAM RADAR IMAGERY AND
INCOMING 12Z MODELS. 925MB TEMPERATURES WILL RISE TO NEAR FREEZING
ALONG AND WEST OF THE VALLEY AHEAD OF THE COLD FRONT...WITH LOW
LEVEL WESTERLY FLOW. FEEL CONFIDENT THIS WILL LEAD TO SFC
TEMPERATURES 31F-34F ACROSS THIS AREA...AND WILL ADJUST HOURLY
TEMPS TONIGHT (USING THE RAP AS A GUIDE). THIS SYSTEM IS A BIT
SLOWER...WITH STRONGEST 925MB COLD AIR ADVECTION HOLDING OFF UNTIL
AFTER 06Z ACROSS THE NORTHERN FA. A BRIEF PERIOD OF GUSTY WINDS
(30MPH-40MPH) LIKELY...BUT WILL BE BRIEF. BLOWING SNOW POTENTIAL
IS LOW GIVEN MINIMAL ADDITIONAL SNOWFALL AND TEMPERATURES NEAR
FREEZING BEFORE STRONGEST WINDS (TOP LAYER OF SNOWPACK WILL BE TOO
DENSE TO BLOW AROUND). SOUTHERLY/WESTERLY WINDS AHEAD OF THE COLD
FRONT WILL BE BREEZY...AND COULD LEAD TO A BIT OF DRIFTING SNOW
WHERE THERE IS LOOSE SNOW COVER.
&&
.AVIATION...
EXPECT PERIODIC VFR CEILINGS WITH SOME BREAKS IN CLOUD COVER
THROUGH THE DAY. LOW VFR/MVFR CEILINGS POSSIBLE LATER THIS EVENING
AND OVERNIGHT AS NEXT LOW PRESSURE SYSTEM MOVES ACROSS THE REGION.
SOME LIGHT SNOW IS ALSO POSSIBLE...LASTING A FEW HOURS WITH MVFR
VSBYS IN THE 3-5 SM RANGE. WINDS WILL BE SOUTHERLY AND INCREASE TO
15 TO 20 KTS THIS AFTN IN THE RRV AND DVL REGION AND THEN TURN
WEST TO NORTHWEST WITH A PERIOD OF GUSTS TO 30 KTS AROUND 06Z.
BEMIDJI AREA TO HAVE SOUTHERLY WINDS 10 TO 15 KTS TODAY THEN TURN
NORTHWEST AFTER 06Z WED. &&
.PREV DISCUSSION... /ISSUED 348 AM CST TUE JAN 15 2013/
SHORT TERM...
SATELLITE EARLY THIS MORNING SHOWS AREAS OF CLOUDS....INTERSPERSED
WITH CLEAR HOLES. THIS CREATING THE USUAL TEMP DIFFERENCES WITH
ZERO TO 5 BELOW IN CLEAR AREAS AND 5 TO 10 ABOVE IN CLOUD AREAS.
EXPECT THIS HODGEPODGE OF CLOUDS/CLEAR WILL CONTINUE THIS MORNING
OVER THE MINNESOTA FCST AREA WHILE MORE GENERAL MID AND HIGH LEVEL
MOISTURE MOVES IN FROM THE WEST INTO ERN ND AHEAD OF THE NEXT
SHORT WAVE. WINDS WILL INCREASE THIS AFTN AND BECOME A BIT BREEZY
IN THE RED RIVER VALLEY AS PRESSURE FALLS AHEAD OF THE NEXT LOW
WHICH WILL DROP SOUTHEAST THROUGH SOUTHERN MANITOBA INTO THE LAKE
OF THE WOODS REGION TONIGHT.
LOOK FOR A BAND OF LIGHT SNOW TO ADVANCE EAST INTO THE DVL REGION
SOUTH OF THE SFC LOW AND AHEAD OF THE SURFACE TROUGH VERY LATE
THIS AFTN AND THEN SPREAD EAST THIS EVENING...ENDING IN THE FAR
EAST OVERNIGHT. WITH SFC LOW TO OUR NORTHEAST AND LACK OF ANY VERY
STRONG VORT...THESE EVENTS OFTEN PRODUCE ONLY MINOR ACCUMS (LESS
THAN AN INCH). EXCEPTION WILL BE LAKE OF THE WOODS WHERE AN INCH
OR TWO WILL OCCUR. BRIEF PERIOD OF NORTHWEST WINDS BEHIND THE LOW
AND TROUGH WITH SUSTAINED VALUES 15 TO 22 KTS AND WIND GUSTS TO NR
30 KTS...ESP IN THE DEVILS LAKE BASIN INTO THE SHEYENNE RIVER
BASIN. WITH SUCH VERY MINIMAL SNOW WITH SYSTEM ANY BLOWING SNOW
ISSUES WILL BE BRIEF AND SHOULDNT BE A HUGE ISSUE. WILL CONTINUE
WITH BLSN MENTION BUT NO ADVISORY FORSEEN.
TEMPS WILL BE AN ISSUE....AS TEMPS SLOWLY RISE TODAY...THEN LOOK
FOR A QUICK RISE WELL INTO THE 20S TO AROUND 30 IN ERN ND AND
PARTS OF THE RED RIVER VALLEY JUST BEHIND SFC TROUGH AS WINDS GO
MORE WEST TO NORTHWEST 04Z-08Z PERIOD. THEREAFTER COLDER AIR WILL
DROP SOUTH AND TEMPS WILL START TO FALL. BUT ALL MODELS SHOW VERY
TIGHT THERMAL GRADIENT FROM MINOT TO COOPERSTOWN TO NEAR FARGO TO
FERGUS FALLS LATE TONIGHT INTO WEDNESDAY. THIS BOUNDARY WILL BE
THE FOCUS FOR A SECOND WEAK LOW WHICH WILL PASS ALONG THE BOUNDARY
WEDNESDAY GIVING ANOTHER SHOT OF LIGHT SNOW. AGREED WITH WFO BIS
TO GO LIKELY POPS FOR A PERIOD WEDNESDAY ALONG THIS THERMAL
GRADIENT FOR UP TO HALF INCH OF SNOW. AFTER THIS LOW
PASSES...COLDER AIR WILL DROP SOUTH THRU ALL THE FCST AREA WED
NIGHT AS HIGH MOVES IN. THEN NEXT SHORT WAVE AND SFC LOW TO
APPROACH LATER THU INTO THURS NIGHT CAUSING THE THERMAL BOUNDARY
TO RETURN NORTH A BIT.
LONG TERM (FRI-MON)...
MODELS IN FAIR AGREEMENT WITH THE EXTENDED TIME FRAME AS 500MB NW
FLOW GIVES WAY TO MORE DIRECTLY NORTH FLOW AS RIDGE AXIS ACROSS THE
NORTH AMERICAN PACIFIC COAST AMPLIFIES NORTH AND PULLS DOWN PRISTINE
ARCTIC AIRMASS BY THE END OF THE PERIOD. FRIDAY WILL BE THE WARMEST
DAY AS WESTERLY SFC WINDS DEVELOP IN THE WAKE OF SFC LOW PASSAGE
ALONG THE INTERNATIONAL BORDER. SCHC OF -SN ACROSS THE N RRV AND
INTO THE BJI AND BDE AREAS FRI. FIRST IN A SERIES OF COLD FRONTS
SURGES SOUTH SAT WITH ANOTHER -SN CHC THEN AGAIN ON SUNDAY ACROSS
THE SOUTH AS THE BRUNT OF THE ARCTIC AIRMASS MAKES ITS WAY INTO THE
REGION SUN PM. TEMPS WELL BELOW NORMAL BY MONDAY WITH HIGHS IN THE 5
TO 15 BELOW RANGE EXPECTED.
&&
.FGF WATCHES/WARNINGS/ADVISORIES...
ND...NONE.
MN...NONE.
&&
$$
TG
AREA FORECAST DISCUSSION
NWS WILMINGTON OH
437 AM EST TUE JAN 15 2013
.SYNOPSIS...
LOW PRESSURE WILL TRACK ACROSS THE SOUTHERN APPALACHIANS TONIGHT
...BRINGING A WINTRY MIX OF PRECIPITATION TO SOUTHERN PORTIONS OF
THE OHIO VALLEY. HIGH PRESSURE WILL THEN BUILD EAST ACROSS THE
AREA LATE THIS WEEK.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
THE FORECAST AREA WILL START OFF THE DAY BEING LODGED BETWEEN
SURFACE RIDGING TO OUR NORTHEAST AND A NEARLY STATIONARY FRONT
DRAPED ACROSS THE APPALACHIANS. A BAND OF LOW CLOUDS ASSOCIATED
WITH COLD ADVECTION WILL LIKELY REMAINED ANCHORED ACROSS OUR NORTH
FOR MUCH OF THE DAY. ACROSS THE SOUTH...CLOUD COVER WILL ALSO
REMAIN IN PLACE AS MOISTURE ALOFT WILL CONTINUE TO STREAM
NORTHEASTWARD BEHIND THE FRONTAL BOUNDARY. IN BETWEEN THERE WILL
BE A SUNNY START TO THE DAY. EVENTUALLY THE COMBINATION OF CLOUD
COVER INCHING ITS WAY SOUTHWARD...AND UPPER LEVEL MOISTURE PUSHING
IN FROM THE SOUTH...WILL RESULT IN CLOUDY CONDITIONS AREA WIDE BY
LATE THIS AFTERNOON. WHERE CLOUD COVER MAY PERSIST ACROSS THE
NORTH...TEMPERATURES COULD STRUGGLE TO REACH THE LOWER 30S. ACROSS
THE REST OF THE AREA EXPECT TEMPERATURES TO REACH THE MIDDLE 30S
THIS AFTERNOON.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH FRIDAY/...
A POSITIVELY TILTED TROUGH EXTENDING FROM THE GREAT LAKES
SOUTHWESTWARD TO NEW MEXICO WILL DIG SOUTHEASTWARD AS A WEAK
SURFACE LOW LIFTS NORTHEASTWARD OUT OF THE WESTERN GULF OF MEXICO.
THIS LOW WILL TRACK ALONG THE STALLED OUT APPALACHIAN FRONTAL
BOUNDARY TONIGHT. AS THIS OCCURS...PRECIPITATION ON THE POLEWARD
SIDE OF THE LOW WILL SPREAD ACROSS SOUTHEASTERN PORTIONS OF THE
FORECAST AREA. THE MAJORITY OF FORECAST MODELS HAVE BEEN TRENDING
FARTHER NORTHWEST OVER THE PAST COUPLE OF RUNS WITH THE
PRECIPITATION TONIGHT. THIS FORECAST PACKAGE FOLLOWS SUIT AND
BRINGS CATEGORICAL POPS TO THE SOUTHEASTERN ZONES WITH A FAST
TAPER OFF TO CHANCE POPS JUST NORTH OF THE INTERSTATE 71 CORRIDOR.
THE MORE DIFFICULT PART OF TONIGHT`S FORECAST WILL BE PRECIPITATION
TYPE. SURFACE TEMPERATURES SHOULD STAY BELOW FREEZING FOR THE MOST
PART...EXCEPT THE ONSET IN THE EVENING...AS OUR AREA SHOULD REMAIN
COMPLETELY IN THE SURFACE COLD SECTOR AS THE LOW PASSES BY TO OUR
SOUTH. TEMPERATURES ALOFT HOWEVER WILL WARM ACROSS THE SOUTHEAST
AS SOME WARMER AIR NUDGES NORTHWARD AS THE LOW PASSES BY. THE
RESULT WILL LIKELY BE A WINTRY MIX OF PRECIPITATION ACROSS THE
SOUTHEAST...TRANSITIONING TO ALL SNOW TOWARD THE EDGE OF THE
PRECIPITATION SHIELD. DUE TO THE ONGOING UNCERTAINTY IN
PRECIPITATION TYPE AND THE FAIRLY LIGHT ACCUMULATIONS CURRENTLY
FORECAST...AM HOLDING OFF ON ANY WINTER WEATHER HEADLINES FOR NOW.
WILL HIGHLIGHT THE POTENTIAL FOR WINTER WEATHER HAZARDS IN THE HWO
FOR THIS PACKAGE.
THE LOW WILL SLIDE NORTHEAST OF THE OHIO VALLEY ON WEDNESDAY AND
PRECIPITATION WILL END AS ANOTHER LOW SWEEPS SOUTHEASTWARD ACROSS
THE NORTHERN GREAT LAKES. THE INCREASED PRESSURE GRADIENT
ASSOCIATED WITH THIS NORTHERN BRANCH LOW WILL BRING SOME GUSTY
WINDS TO THE AREA DURING THE DAY WEDNESDAY.
LOW LEVEL HIGH PRESSURE WILL SLOWLY BUILD FROM THE WEST ACROSS THE
AREA WEDNESDAY NIGHT THROUGH THURSDAY NIGHT AND WILL BE CENTERED
ACROSS THE REGION BY FRIDAY. TEMPERATURES ARE EXPECTED TO BE
SEASONABLE DURING THIS TIME PERIOD. ANOTHER LOW IS EXPECTED TO
SLIDE PAST OUR AREA TO THE SOUTH THURSDAY AND THURSDAY NIGHT.
HOWEVER...ENOUGH RIDGING SHOULD BE IN PLACE ACROSS OUR AREA TO KEEP
ANY PRECIPITATION TO OUR SOUTH.
&&
.LONG TERM /FRIDAY THROUGH MONDAY/...
ANOTHER SYSTEM DROPS INTO THE SUBTLE GREAT LAKES TROF ON
SATURDAY. MODELS DIFFER ON THE STRENGTH OF THIS SYSTEM. THE GFS IS
THE STRONGEST...WITH THE ECMWF AND CMC BEING WEAKER. TYPICALLY
THERE IS A WIDE RANGE OF SOLUTIONS IN A PATTERN LIKE THIS AS THE
MODELS STRUGGLE TO DECIPHER THESE WEAK DISTURBANCES CORRECTLY.
LEANED WITH THE CONSENSUS ECMWF/CMC SOLUTION...WHICH KEEPS
SATURDAY DRY. A COLD FRONT THEN SWINGS ACROSS THE FA
SUNDAY...ALLOWING ARCTIC AIR TO SPILL INTO THE FA. THIS SHOULD
KICK OFF A ROUND OF SHSN FOR SUNDAY AND MONDAY.
AS FOR TEMPERATURES...CAA ON THURSDAY WILL KEEP HIGHS IN THE LOWER
30S IN THE NW TO AROUND 40 IN THE EXTREME S. SOME WAA WILL BRING
WARMER AIR IN FOR FRIDAY AND SATURDAY. HIGHS FRIDAY WILL BE IN THE
UPPER 30S TO LOWER 40S...WITH 40S FOR HIGHS ON SATURDAY.
TEMPERATURES WILL TAKE A DOWN TURN ON WITH THE PASSAGE OF THE COLD
FRONT AS HIGHS WILL RANGE FROM THE MID 30S IN THE N TO AROUND 40S
IN NRN KY. ON MONDAY THEY WILL STRUGGLE TO RECOVER INTO THE MID 20
IN THE NW COUNTIES...WITH SOUTHERN LOCATIONS POSSIBLY MAKING THE
MID 30S.
&&
.AVIATION /09Z TUESDAY THROUGH SATURDAY/...
MVFR CIGS ARE HANGING TOUGH ACROSS THE REGION. ITS HARD TO TELL ON
THE IR SATELLITE IMAGES DUE TO SOME HIGHER CLOUDS...BUT THE LOWER
CLOUDS LOOK LIKE THEY MAY BE EXPANDING ACROSS PARTS OF SOUTHWEST
OHIO AND NORTHERN KENTUCKY. MEANWHILE...THE NORTHERN BAND OF LOWER
CLOUDS ALONG AND NORTH OF I-70 DOES APPEAR TO BE TRYING TO ERODE FROM
THE SOUTH. THIS WILL MAKE FOR A DIFFICULT CIG FORECAST THIS
MORNING. THE LATEST RAP 925 MB RH SEEMS TO HAVE A DECENT HANDLE ON
THE CURRENT LOW CLOUDS SO WILL TREND FORECAST IN THAT DIRECTION.
GIVEN NORTHERLY LOW LEVEL FLOW PERSISTING...NOT SURE HOW MUCH MORE
EROSION WE WILL SEE ON THE SOUTHERN EDGE OF THE NORTHERN BAND AND
WOULD NOT BE SURPRISED IF THIS EVEN STARTS TO EXPAND BACK DOWN
TOWARD THE SOUTH. WILL GO AHEAD AND ERROR ON THE PESSIMISTIC SIDE
AND GENERALLY ALLOW FOR MVFR CIGS THROUGH MID MORNING AT THE TAF
SITES. WILL THEN GO AHEAD AND ALLOW FOR THE MVFR CIGS TO DISSIPATE
THROUGH LATE MORNING (ALTHOUGH THE RAP IS HANGING ON TO THE LOW
LEVEL MOISTURE THROUGH THE DAY). FOCUS WILL THEN SHIFT TOWARD THE
SYSTEM WORKING UP FROM THE SOUTH LATER TODAY INTO TONIGHT. MODELS
HAVE BEEN TRENDING FARTHER NORTH WITH THIS SYSTEM. RIGHT NOW THE
I-71 CORRIDOR APPEARS TO BE RIGHT ON THE EDGE OF ANY PCPN SO WILL
KEEP THE TAFS DRY AT THIS POINT AND JUST ALLOW FOR SOME LOWERING
CIGS THROUGH THE LAST PART OF THE PERIOD.
OUTLOOK...NO SIGNIFICANT WEATHER IS EXPECTED.
&&
.ILN WATCHES/WARNINGS/ADVISORIES...
OH...NONE.
KY...NONE.
IN...NONE.
&&
$$
SYNOPSIS...LATTO
NEAR TERM...LATTO
SHORT TERM...LATTO
LONG TERM...SITES
AVIATION...JGL
AREA FORECAST DISCUSSION
NWS WILMINGTON OH
1249 AM EST TUE JAN 15 2013
.SYNOPSIS...
LOW PRESSURE WILL TRACK TOWARDS THE SOUTHERN APPALACHIANS OVER THE
NEXT DAY OR TWO...LEADING TO INCREASED MOISTURE IN KENTUCKY AND
WEST VIRGINIA. HIGH PRESSURE IN INDIANA AND NORTHWEST OHIO WILL
KEEP THIS MOISTURE ALONG AND SOUTH OF THE OHIO RIVER TONIGHT AND
TUESDAY NIGHT. A WEAK COLD FRONT WILL CROSS THE NORTHERN OHIO
VALLEY ON THURSDAY.
&&
.NEAR TERM /UNTIL 6 AM THIS MORNING/...
ECHOES HAVE PASSED OFF TO THE EAST OF THE FORECAST AREA. SO NO
THREAT OF PRECIPITATION THROUGH THE NIGHT. CLOUDS ARE STARTING TO
CLEAR FROM THE SOUTHWEST. APPEARS THAT THEY WILL HANG ON LONGEST
IN THE NORTHWEST COUNTIES AND ALSO IN THE FAR SOUTHEAST. FORECAST
LOW TEMPERATURES STILL LOOK ON TRACK.
&&
.SHORT TERM /6 AM THIS MORNING THROUGH WEDNESDAY NIGHT/...
HIGH PRESSURE IN THE MIDWEST NOSING INTO THE GREAT LAKES
AFFECTING NORTHERN OHIO VALLEY WILL BATTLE WITH THE INCREASED
MOISTURE TO THE SOUTHEAST ALONG THE APPALACHIANS AND WEAK SURFACE
LOW PRESSURE RIDING NORTHEAST FROM THE GULF STATES.
EXPECT CLOUDS TO THE SOUTHEAST AND A CHANCE FOR PRECIPITATION
TUESDAY NIGHT. THIS IS A COMBINATION OF THE NORTHEAST MOVING
SURFACE LOW IN THE WESTERN CAROLINAS...AND AN UPPER LEVEL TROUGH
MOVING EAST ACROSS THE CENTRAL UNITED STATES. ANY TYPE OF DISJOINT
IN THE TWO WILL LEAD TO LESS THREAT FOR PRECIPITATION IN MY
SOUTHEAST COUNTIES...BUT THE FAVORABLE COMBINATION OF THE TWO
WORKING TOGETHER IS NOTED ON MOST MODEL SOLUTIONS THIS AFTERNOON.
MAXIMIZED THE CHANCE FOR RAIN OR A RAIN/SNOW MIX AT MIDNIGHT AND
QUICKLY RAMPED THE POPS DOWN BY DAYBREAK. THERMAL PROFILES AT
PORTSMOUTH FROM BUFKIT SUGGEST SOME TYPE OF A MIX ALTHOUGH THE
COLD POOL UNDERNEATH THE WARM LAYER ALOFT MAY NOT BE ENOUGH TO RE-
FREEZE THE RAIN FOR SLEET...AND THE SURFACE TEMPERATURES HOVERING
AT OR JUST BELOW FREEZING MAY NOT PRODUCE FREEZING RAIN. WITH SUCH
A NARROW CUTOFF TO THE NORTHWEST BETWEEN PRECIP AND DRY
CONDITIONS...AND SURFACE TEMPERATURES HOVERING RIGHT AROUND THE
FREEZING MARK...JUST WENT WITH WHAT THE THICKNESSES SUPPORTED AS
A WX TYPE IN THE SOUTHEAST...PRIMARILY RAIN/FREEZING RAIN THAT MAY
BE MIXED WITH SNOW.
TEMPERATURES WERE NOT SIGNIFICANTLY CHANGED IN ANY
PERIOD...LOWERED THEM 3-4 DEGREES TOMORROW NIGHT IN THE NORTHWEST
WITH THE THOUGHT OF GENERALLY CLEAR SKIES AND LIGHT WINDS.
&&
.LONG TERM /THURSDAY THROUGH MONDAY/...
SPLIT FLOW ACROSS THE U.S. AT THE BEGINNING OF THE PERIOD LEAVES
THE OHIO VALLEY BETWEEN SYSTEMS. THERE IS A SYSTEM IN THE NORTHERN
STREAM THAT WAS BRINGING PCPN TO THE GREAT LAKES. MEANWHILE A
CLOSED H5 LOW IS IN THE SRN PLAINS. THIS SECOND SYSTEM SLIDES E
THU NGT INTO FRI...KEEPING ITS PCPN OUT OF THE FA.
WEAK ENERGY KEEPS DROPPING ACROSS THE GREAT LAKES...WITH A SYSTEM
SWINGING THROUGH ON FRIDAY. ANOTHER SYSTEM DROPS INTO THE SUBTLE
GREAT LAKES TROF ON SATURDAY. MODELS DIFFER ON THE STRENGTH OF THIS
SYSTEM. THE GFS IS THE STRONGEST...WITH THE ECMWF AND CMC BEING
WEAKER. TYPICALLY THERE IS A WIDE RANGE OF SOLUTIONS IN A PATTERN
LIKE THIS AS THE MODELS STRUGGLE TO DECIPHER THESE WEAK DISTURBANCES
CORRECTLY. LEANED WITH THE CONSENSUS ECMWF/CMC SOLUTION...WHICH
KEEPS SATURDAY DRY. A COLD FRONT THEN SWINGS ACROSS THE FA
SUNDAY...ALLOWING ARCTIC AIR TO SPILL INTO THE FA. THIS SHOULD KICK
OFF A ROUND OF SHSN FOR SUNDAY AND MONDAY.
AS FOR TEMPERATURES...CAA ON THURSDAY WILL KEEP HIGHS IN THE LOWER
30S IN THE NW TO AROUND 40 IN THE EXTREME S. SOME WAA WILL BRING
WARMER AIR IN FOR FRIDAY AND SATURDAY. HIGHS FRIDAY WILL BE IN THE
UPPER 30S TO LOWER 40S...WITH 40S FOR HIGHS ON SATURDAY.
TEMPERATURES WILL TAKE A DOWN TURN ON WITH THE PASSAGE OF THE COLD
FRONT AS HIGHS WILL RANGE FROM THE MID 30S IN THE N TO AROUND 40S
IN NRN KY. ON MONDAY THEY WILL STRUGGLE TO RECOVER INTO THE MID 20
IN THE NW COUNTIES...WITH SOUTHERN LOCATIONS POSSIBLY MAKING THE
MID 30S.
&&
.AVIATION /06Z TUESDAY THROUGH SATURDAY/...
MVFR CIGS ARE HANGING TOUGH ACROSS THE REGION. ITS HARD TO TELL ON
THE IR SATELLITE IMAGES DUE TO SOME HIGHER CLOUDS...BUT THE LOWER
CLOUDS LOOK LIKE THEY MAY BE EXPANDING ACROSS PARTS OF SOUTHWEST
OHIO AND NORTHERN KENTUCKY. MEANWHILE...THE NORTHERN BAND OF LOWER
CLOUDS ALONG AND NORTH OF I-70 DOES APPEAR TO BE TRYING TO ERODE FROM
THE SOUTH. THIS WILL MAKE FOR A DIFFICULT CIG FORECAST THIS
MORNING. THE LATEST RAP 925 MB RH SEEMS TO HAVE A DECENT HANDLE ON
THE CURRENT LOW CLOUDS SO WILL TREND FORECAST IN THAT DIRECTION.
GIVEN NORTHERLY LOW LEVEL FLOW PERSISTING...NOT SURE HOW MUCH MORE
EROSION WE WILL SEE ON THE SOUTHERN EDGE OF THE NORTHERN BAND AND
WOULD NOT BE SURPRISED IF THIS EVEN STARTS TO EXPAND BACK DOWN
TOWARD THE SOUTH. WILL GO AHEAD AND ERROR ON THE PESSIMISTIC SIDE
AND GENERALLY ALLOW FOR MVFR CIGS THROUGH MID MORNING AT THE TAF
SITES. WILL THEN GO AHEAD AND ALLOW FOR THE MVFR CIGS TO DISSIPATE
THROUGH LATE MORNING (ALTHOUGH THE RAP IS HANGING ON TO THE LOW
LEVEL MOISTURE THROUGH THE DAY). FOCUS WILL THEN SHIFT TOWARD THE
SYSTEM WORKING UP FROM THE SOUTH LATER TODAY INTO TONIGHT. MODELS
HAVE BEEN TRENDING FARTHER NORTH WITH THIS SYSTEM. RIGHT NOW THE
I-71 CORRIDOR APPEARS TO BE RIGHT ON THE EDGE OF ANY PCPN SO WILL
KEEP THE TAFS DRY AT THIS POINT AND JUST ALLOW FOR SOME LOWERING
CIGS THROUGH THE LAST PART OF THE PERIOD.
OUTLOOK...NO SIGNIFICANT WEATHER IS EXPECTED.
&&
.ILN WATCHES/WARNINGS/ADVISORIES...
OH...NONE.
KY...NONE.
IN...NONE.
&&
$$
SYNOPSIS...FRANKS
NEAR TERM...
SHORT TERM...FRANKS
LONG TERM...SITES
AVIATION...JGL
AREA FORECAST DISCUSSION
NWS CLEVELAND OH
1146 PM EST MON JAN 14 2013
.SYNOPSIS...
HIGH PRESSURE WILL BUILD EAST ACROSS THE OHIO VALLEY AND LOWER
GREAT LAKES REGION TONIGHT INTO TUESDAY. TUESDAY NIGHT LOW
PRESSURE WILL ACROSS ACROSS THE NORTHERN GREAT LAKES REGION AND
DRAG A COLD FRONT ACROSS THE REGION LATE WEDNESDAY. A STRONGER
COLD FRONT WILL PASS THROUGH ON THURSDAY.
&&
.NEAR TERM /UNTIL 6 AM TUESDAY MORNING/...
A RIDGE IS BUILDING ACROSS THE AREA OVERNIGHT. THE QUESTION IS
WHAT WILL HAPPEN WITH THE CLOUDS. THE RUC/RAP MODEL KEEPS THE LOW
CLOUDS ACROSS THE ENTIRE FORECAST AREA ALL NIGHT. THE NAM MODEL
HAS THE LOW CLOUDS GONE BY MIDNIGHT...WHILE THE GFS MODEL SLOWLY
DECREASES THE CLOUDS OVERNIGHT. WENT CLOSER TO THE RAP MODEL AND
DECREASED THE CLOUDS OVER NORTHWEST OHIO AS PER THE SATELLITE
PHOTOS WHICH ARE SHOWING THE CLOUDS DECREASING BUT SOME CLOUDS ARE
REGENERATING. THE LOWS ARE TOUGH BECAUSE OF THE SKY COVER DILEMMA.
&&
.SHORT TERM /6 AM TUESDAY MORNING THROUGH THURSDAY NIGHT/...
HIGH PRESSURE CONTINUES TO BUILD ACROSS THE LOWER OHIO VALLEY
TUESDAY WITH MODELS SHOWING A SLIGHT INCREASE IN MOISTURE...MAINLY
HIGH LEVEL...ACROSS THE AREA TUESDAY EVENING. WILL CONTINUE WITH A
FAIR FORECAST THROUGH TUESDAY NIGHT. WEDNESDAY A COLD FRONT WILL
DROP ACROSS THE AREA AS THE PARENT LOW MOVES EAST ACROSS THE
CENTRAL AND NORTHERN GREAT LAKES INTO ONTARIO. MODELS BRING A
RATHER THIN SWATH OF LIMITED MOISTURE ACROSS THE AREA IN THE
AFTERNOON AS 850MB TEMPS DROP TO ABOUT -8 TO -9C EXTREME NORTHEAST
OHIO AND NWRN PA. GIVEN A 39 DEGREE LAKE -8C IS CERTAINLY NOT
EXTREME BUT COULD SEE A FEW SNOW SHOWERS DEVELOP DURING THE DAY
AND INTO THE NIGHT SO WILL HAVE SLIGHT CHANCE IN THE GRIDS FOR
WEDNESDAY...INCREASING TO CHANCE POPS WEDNESDAY NIGHT AS GFS TAKES
850MB TEMPS TO -13C TO -14C. THURSDAY THE GFS BEGINS WITH -14C
WITH THE NEXT COLD FRONT UPSTREAM ACROSS THE CENTRAL LAKES. WILL
INCREASE POPS TO LIKELY THURSDAY MORNING AS THE FRONT MOVES IN BUT
THEN BACK OFF TO CHANCE IN THE AFTERNOON AS HIGH PRESSURE BUILDS
ACROSS THE LOWER OHIO VALLEY AND DRIER AIR MOVES IN.
&&
.LONG TERM /FRIDAY THROUGH MONDAY/...
A BROAD TROUGH OVER NORTH AMERICA WILL DEEPEN OVER THE EASTERN
UNITED STATES DURING THE EXTENDED...ALLOWING AN ARCTIC AIRMASS TO
SETTLE SOUTH OVER THE REGION EARLY NEXT WEEK. LOW LEVEL BAROCLINIC ZONE
IN PLACE ACROSS THE GREAT LAKES REGION WILL LIFT NORTH ON FRIDAY AS
LOW PRESSURE APPROACHES FROM THE WEST. TEMPERATURES WILL BE AT OR
ABOVE NORMAL ON FRIDAY/SATURDAY BEFORE A SECONDARY CLIPPER SLIDES
THROUGH ON SATURDAY NIGHT AND PULLS A COLD FRONT SOUTH ACROSS THE
REGION. SCATTERED SNOW SHOWERS ARE EXPECTED ALONG THE FRONT...WITH
LAKE EFFECT INCREASING INTO SUNDAY AS THE 850MB TEMPERATURES FALL TO
-15 TO -18C AND INSTABILITY INCREASES OVER THE LAKE. A SECONDARY
WAVE WILL DIG THROUGH THE UPPER TROUGH ON MONDAY...FORCING AN EVEN
COLDER AIRMASS WITH 850MB TEMPS BELOW -20C OVER THE REGION FOR THE
EARLY PART OF NEXT WEEK.
&&
.AVIATION /06Z TUESDAY THROUGH SATURDAY/...
HIGH PRESSURE TO THE WEST WILL CONTINUE BUILDING INTO THE AREA
OVERNIGHT. SATELLITE SHOWING AREAS OF MVFR CLOUDS FROM ERI-CLE-MFD
AND FDY. THESE MVFR CLOUDS APPEAR TO BE ERODING FROM BOTH THE
SOUTHEAST AND NORTHWEST EARLY TONIGHT WITH VFR AT TOL...AS WELL AS
VFR AT CAK AND YNG. THINKING THAT THESE CLOUDS WILL CONTINUE TO
SLOWLY DISSIPATE THROUGH THE OVERNIGHT WITH MVFR SITES BECOMING
VFR BY DAYBREAK OR SHORTLY AFTER. VFR EXPECTED THROUGH TUESDAY
ACROSS SITES WITH LIGHT NORTHERLY-NE WINDS LESS THAN 10KT. SOME
MID TO HIGH CLOUDS BUILDING NORTHWARD OVER OHIO TUESDAY NIGHT.
OUTLOOK...NON-VFR POSSIBLE WEDNESDAY NIGHT AND THURSDAY IN NE
OHIO/NW PA.
&&
.MARINE...
PRESSURE GRADIENT SHOULD CONTINUE TO WEAKEN THROUGH THE EVENING
ALLOWING WINDS TO CONTINUE TO DIMINISH. WEAK HIGH PRESSURE RIDGE
OVER THE LAKE TUE SHOULD PROVIDE LIGHT AND VARIABLE WINDS THAT WILL
BECOME SW BY WED MORNING AHEAD OF A COLD FRONT THAT WILL CROSS
THE LAKE LATE WED NIGHT. WIND SPEEDS COULD BE CLOSE TO GALE FORCE
FOR A WHILE AROUND WED EVENING.
WINDS SHOULD TURN MORE NW THU AND CONTINUE TO DIMINISH THRU THU
NIGHT AS ANOTHER RIDGE OF HIGH PRESSURE SPREADS EAST OVER OHIO. THE
RIDGE SHOULD DROP SE FRI TO ALLOW THE FLOW TO TURN SW AGAIN AND
BEGIN TO INCREASE BY FRI NIGHT.
&&
.CLE WATCHES/WARNINGS/ADVISORIES...
OH...NONE.
PA...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...TK
NEAR TERM...KIELTYKA
SHORT TERM...TK
LONG TERM...KEC
AVIATION...ABE
MARINE...ADAMS
AREA FORECAST DISCUSSION
NWS TULSA OK
541 AM CST TUE JAN 15 2013
.AVIATION...
CONCERNING TAF SITES KTUL/KRVS/KBVO/KMLC/KXNA/KFYV/KFSM.
MID/HIGH LEVEL CLOUDS ARE BEGINNING TO PUSH INTO EASTERN OKLAHOMA
AND NORTHWEST ARKANSAS THIS MORNING. A BROKEN TO OVERCAST MID
CLOUD DECK IS EXPECTED TO REMAIN ACROSS THE REGION THROUGH THE
EVENING HOURS BEFORE CLEARING OFF FROM WEST TO EAST. NORTHERLY
WINDS SHOULD ALSO BEGIN TO SHIFT OUT OF THE WEST AND NORTHWEST
OVERNIGHT TONIGHT. VFR CONDITIONS SHOULD PERSIST AT ALL TAF SITES
THROUGH THE PERIOD.
&&
.PREV DISCUSSION... /ISSUED 343 AM CST TUE JAN 15 2013/
DISCUSSION...
LARGE SCALE TROUGHING THAT HAS REMAINED TO OUR WEST FOR SEVERAL
DAYS IS NOW IN THE PROCESS OF SLOWLY SHIFTING EASTWARD. YET
ANOTHER SMALL SCALE WAVE WILL EJECT AHEAD OF THE UPPER TROUGH
TODAY WITH PRECIP DEVELOPING ACROSS EASTERN TEXAS AND SPREADING
NORTHEASTWARD THROUGH THE AFTERNOON. FAR SE OK WILL BE THE ON THE
NORTHERN PERIPHERY OF THIS PRECIP SHIELD PER VARIOUS MODEL QPF
FIELDS...AND THIS ALIGNS FAIRLY WELL WITH THE ONGOING
STRENGTHENING OF MID LEVEL FRONTOGENETIC BAND IN LATEST RAP DATA.
MEASURABLE PRECIP CHANCES WILL BE LOW ACROSS FAR SE OK WITH ANY
PRECIP THAT DOES FALL EXPECTED TO BE A SLEET / SNOW MIX. ALL
PRECIP WILL HAVE SHIFTED WELL EAST OF THE FORECAST AREA BY THIS
AFTERNOON...WITH TEMPS CONTINUED BELOW NORMAL TODAY AND TONIGHT.
THE BASE OF THE UPPER TROUGH IS LIKELY TO DEVELOP A CLOSED LOW
THAT WILL TRACK ACROSS CENTRAL TEXAS ON WEDNESDAY...WHILE THE
LARGER TROUGH AXIS MAINTAINS A POSITIVE TILT KEEPING ASSOCIATED
PRECIP SHUNTED INTO THE SOUTHEASTERN STATES. WEDNESDAY WILL ALSO
MARK THE MORE NOTICEABLE WARM UP WITH TEMPS RETURNING TO NEAR MID
JANUARY NORMALS.
THE WARMING TREND WILL BE STALLED ON THURSDAY AS A WEAK COLD FRONT
SLIDES THROUGH THE AREA...WITH A MORE ROBUST WARM UP EXPECTED
FRIDAY AND SATURDAY. THE NEXT BIG CHANGE WILL BE SATURDAY NIGHT AS
A STRONGER COLD FRONT SLIDES INTO THE SOUTHERN PLAINS. GENERALLY
SIDED TOWARD THE ECMWF SOLUTION WHICH HAS BEEN CONSISTENT IN
SHOWING THIS FIRST COLD FRONT TO OFFER A MODEST COOL DOWN...AND
QUICKLY FOLLOWED BY A MUCH STRONGER COLD FRONT ON MONDAY. THIS
AIRMASS MARKED BY A 1050+ MB SURFACE PRESSURE WILL PUSH TEMPS WELL
BELOW NORMAL FOR THE FIRST PART OF NEXT WEEK. DRY WEATHER WILL
PREVAIL WITH THE POSSIBLE EXCEPTION OF LIGHT PRECIP ASSOCIATED
WITH THE EARLY WEEK COLD FRONT.
&&
.PRELIMINARY POINT TEMPS/POPS...
TUL 39 20 47 27 / 0 0 0 10
FSM 40 20 46 27 / 10 0 10 10
MLC 40 17 47 27 / 10 0 10 10
BVO 37 13 47 22 / 0 0 0 10
FYV 36 13 42 23 / 10 0 10 10
BYV 36 18 42 27 / 10 0 10 10
MKO 38 16 45 26 / 10 0 10 10
MIO 34 16 45 25 / 0 0 0 10
F10 39 18 46 27 / 0 0 10 10
HHW 39 19 47 28 / 20 10 10 10
&&
.TSA WATCHES/WARNINGS/ADVISORIES...
OK...NONE.
AR...NONE.
&&
$$
AVIATION...20
AREA FORECAST DISCUSSION
NWS TULSA OK
343 AM CST TUE JAN 15 2013
.DISCUSSION...
LARGE SCALE TROUGHING THAT HAS REMAINED TO OUR WEST FOR SEVERAL
DAYS IS NOW IN THE PROCESS OF SLOWLY SHIFTING EASTWARD. YET
ANOTHER SMALL SCALE WAVE WILL EJECT AHEAD OF THE UPPER TROUGH
TODAY WITH PRECIP DEVELOPING ACROSS EASTERN TEXAS AND SPREADING
NORTHEASTWARD THROUGH THE AFTERNOON. FAR SE OK WILL BE THE ON THE
NORTHERN PERIPHERY OF THIS PRECIP SHIELD PER VARIOUS MODEL QPF
FIELDS...AND THIS ALIGNS FAIRLY WELL WITH THE ONGOING
STRENGTHENING OF MID LEVEL FRONTOGENETIC BAND IN LATEST RAP DATA.
MEASURABLE PRECIP CHANCES WILL BE LOW ACROSS FAR SE OK WITH ANY
PRECIP THAT DOES FALL EXPECTED TO BE A SLEET / SNOW MIX. ALL
PRECIP WILL HAVE SHIFTED WELL EAST OF THE FORECAST AREA BY THIS
AFTERNOON...WITH TEMPS CONTINUED BELOW NORMAL TODAY AND TONIGHT.
THE BASE OF THE UPPER TROUGH IS LIKELY TO DEVELOP A CLOSED LOW
THAT WILL TRACK ACROSS CENTRAL TEXAS ON WEDNESDAY...WHILE THE
LARGER TROUGH AXIS MAINTAINS A POSITIVE TILT KEEPING ASSOCIATED
PRECIP SHUNTED INTO THE SOUTHEASTERN STATES. WEDNESDAY WILL ALSO
MARK THE MORE NOTICEABLE WARM UP WITH TEMPS RETURNING TO NEAR MID
JANUARY NORMALS.
THE WARMING TREND WILL BE STALLED ON THURSDAY AS A WEAK COLD FRONT
SLIDES THROUGH THE AREA...WITH A MORE ROBUST WARM UP EXPECTED
FRIDAY AND SATURDAY. THE NEXT BIG CHANGE WILL BE SATURDAY NIGHT AS
A STRONGER COLD FRONT SLIDES INTO THE SOUTHERN PLAINS. GENERALLY
SIDED TOWARD THE ECMWF SOLUTION WHICH HAS BEEN CONSISTENT IN
SHOWING THIS FIRST COLD FRONT TO OFFER A MODEST COOL DOWN...AND
QUICKLY FOLLOWED BY A MUCH STRONGER COLD FRONT ON MONDAY. THIS
AIRMASS MARKED BY A 1050+ MB SURFACE PRESSURE WILL PUSH TEMPS WELL
BELOW NORMAL FOR THE FIRST PART OF NEXT WEEK. DRY WEATHER WILL
PREVAIL WITH THE POSSIBLE EXCEPTION OF LIGHT PRECIP ASSOCIATED
WITH THE EARLY WEEK COLD FRONT.
&&
.PRELIMINARY POINT TEMPS/POPS...
TUL 39 20 47 27 / 0 0 0 10
FSM 40 20 46 27 / 10 0 10 10
MLC 40 17 47 27 / 10 0 10 10
BVO 37 13 47 22 / 0 0 0 10
FYV 36 13 42 23 / 10 0 10 10
BYV 36 18 42 27 / 10 0 10 10
MKO 38 16 45 26 / 10 0 10 10
MIO 34 16 45 25 / 0 0 0 10
F10 39 18 46 27 / 0 0 10 10
HHW 39 19 47 28 / 20 10 10 10
&&
.TSA WATCHES/WARNINGS/ADVISORIES...
OK...NONE.
AR...NONE.
&&
$$
LONG TERM....07
AREA FORECAST DISCUSSION
NWS GREENVILLE-SPARTANBURG SC
102 AM EST TUE JAN 15 2013
.SYNOPSIS...
A SURFACE FRONT WILL BECOME STATIONARY OVER THE REGION THROUGH THE
MIDDLE OF THE WEEK AND MAINTAIN HIGH AMOUNTS OF CLOUDINESS AND
CHANCES OF RAIN. HIGH PRESSURE IS EXPECTED TO BUILD IN BRIEFLY FROM
THE NORTH THURSDAY...BEFORE A LOW PRESSURE SYSTEM MOVES NORTHEAST
OUT OF THE GULF OF MEXICO AND TRACKS TOWARD THE SOUTH CAROLINA COAST
THROUGH EARLY FRIDAY.
&&
.NEAR TERM /THROUGH TODAY/...
930 PM UPDATE...CURRENT FORECAST IS ON TRACK. THE FRONTAL BOUNDARY
HAS MOVED THROUGH THE NC MOUNTAINS AND CURRENTLY LOCATED FROM
NORTHEAST GEORGIA...NE THROUGH THE NC FOOTHILLS. SOLID PRECIP BANDS
ALONG AND NORTH OF THE FRONT WERE MOVING EASTWARD ACROSS
NORTHEAST GEORGIA AND NC MOUNTAINS. THESE BANDS OF PRECIP WILL
CONTINUE TO PROGRESS EAST ACROSS THE REST OF OUR CWA OVERNIGHT
HOURS.
AT 215 PM...MAIN FEATURE DURING THE NEAR TERM OF THE FORECAST WILL
BE THE SE TO NE ORIENTED FRONTAL BOUNDARY THAT IS CURRENTLY LOCATED
FROM NORTHERN GA...NE THROUGH THE NC MOUNTAINS. A WAVE OF LOW
PRESSURE WAS ALONG THE NC/SC BORDER BETWEEN AVL AND CEU AT 18Z. AS
THE WAVE MOVES EAST INTO THE NC PIEDMONT LATE THIS AFTERNOON...THE
FRONTAL BOUNDARY WIL BE ALLOWED TO SAG SOUTHWARD INTO THE NORTHERN
PORTION OF THE SC UPSTATE AND THE SOUTHERN NC PIEDMONT. THE BOUNDARY
IS THEN EXPECTED TO REMAIN QUASI-STATIONARY IN THAT POSITION THROUGH
TUE AS DEEP LAYERED SW FLOW REMAINS OVER THE AREA AND ROUGHLY
PARALLEL WITH THE FRONT..
RAINFALL WILL CONTINUE TO BE WIDESPREAD...ESPECIALLY ACROSS THE NC
MOUNTAINS. LOCATIONS IN GRAHAM AND SWAIN COUNTIES HAVE ALREADY
PICKED UP IN EXCESS OF 2 INCHES OF RAIN AND COUNTY OFFICIALS REPORT
THAT STREAMS ARE RUNNING HIGH. REGIONAL RADARS CONTINUE TO SHOW THE
HEAVIEST RAINFALL OCCURING IN THOSE AREAS...AND THAT SHOULD CONTINUE
FOR SEVERAL MORE HOURS. SOME AREAL FLOODING MAY OCCUR AND MAY NEED
TOP BE ADDRESSED EVENTUALLY IN AN AREAL FLOOD WARNING. THE CURRENT
FLOOD WATCH IS WELL PLACED AND WILL CONTINUE IT IN TIME AND SPACE.
MODELS ARE INDICATING THAT THE BEST UPPER DIVERGENCE WILL GRADUALLY
BECOME ESTABLISHED WEST OF THE NC MOUNTAINS OVER EASTERN TN AS AN
UPPER JET STREAK MOVES INTO THE LOWER GREAT LAKES. STAYED CLOSE TO
HPC QPF WITH SOME MODIFICATIONS FOR LOCAL AFFECTS USING GMOS. THIS
QPF FORECAST INDICATES THAT WIDESPREAD SIGNIFICANT FLOODING SHOULD
NOT OCCUR.
THE TEMPERATURE FORECAST WILL BE A CHALLENGE...ESPECIALLY ACROSS THE
PIEDMONT AREAS WHERE A TIGHT GRADIENT WILL EXIST IN THE VICINITY OF
THE FRONTAL BOUNDARY. SOUTHERN AREAS THIS AFTERNOON HAVE TEMPS IN
THE MID 70S...AND SOMETHING SIMILAR IS LIKELY TO OCCUR TUE
AFTERNOON. USED A BLEND OF MOS AND NAM12 TO CREATE MIN/MAX TEMP
GRIDS. WILL CONTINUE TO FORECAST CATEGORICAL POPS OVER THE
MOUNTAINS...TAPERING TO A LOW CHANCE OF SOUTHERN AREAS.
&&
.SHORT TERM /TONIGHT THROUGH THURSDAY NIGHT/...
AS OF 230 PM MONDAY...H8-H7 FRONTOGENESIS WILL BE STRONGEST WEST OF
THE MOUNTAINS AND NORTHWARD ACROSS THE CENTRAL APPALACHIANS TUE
NIGHT. HOWEVER...A PERIOD OF STRONGER UPSLOPE DEVELOPS ALONG THE
SOUTHERN SLOPES FROM 00-06 UTC WED. I/VE GONE WITH A BLEND OF THE
HPC QPF AND THE WETTER GFS QPF DURING THIS TIME WHICH ADDS ABOUT A
HALF INCH OF PCPN TO THE CURRENT FLOOD WATCH AREAS TUE NIGHT. OWING
TO THIS ADDITIONAL RAINFALL...WE/LL CONTINUE THE FLOOD WATCH THROUGH
12 UTC WED. LATER TUE NIGHT THE LLVL FLOW BECOMES MORE WESTERLY AND
THE LLVL CONVERGENCE WEAKENS AS UPPER DIVERGENCE LIFTS WELL NORTH OF
THE REGION. THIS SHOULD CAUSE PCPN TO BECOME LIGHTER AND END SHORTLY
AFTER 12 UTC OVER THE FORECAST AREA. DOWNSLOPE FLOW AND A FAIRLY
MILD AIRMASS SHOULD HELP TEMPS WARM TO AROUND 60 OVER THE PIEDMONT
WEDNESDAY AFTERNOON. IN FACT...IT MAY BE A FEW DEGREES WARMER THAN
THAT.
A SRN STREAM UPPER LOW WILL APPROACH THE REGION ON THURSDAY. THE NAM
IS SIGNIFICANT OUTLIER AS IT TAKES THE LOW MUCH FARTHER NORTH THAN
THE GFS...CANADIAN OR ECMWF. THE LOW IS ALSO SIGNIFICANTLY STRONGER
ON THAT MODEL. THE 0900 UTC SREF SFC PATTERN IS NOWHERE CLOSE TO THE
NAM/S AND MATCHES THE GLOBAL MODELS BETTER. WE WENT CLOSEST TO THE
GFS FOR THIS RUN. THIS IS STILL WETTER THAN THE 12 UTC ECMWF WHICH
HAS VERY LITTLE PCPN OVER THE FA AS THE WAVE DAMPENS OUT MUCH MORE
QUICKLY AS IT MOVES INTO THE CONFLUENT UPPER FLOW UNDER A DIGGING
NRN STREAM LOW WAVE TROUGH. AT ANY RATE...I DO HAVE A SLIGHT CHANCE
OF SNOW IN THE GRIDS OVER THE MTNS WED NIGHT...BUT THIS SHOULD
AMOUNT TO LITTLE OR NOTHING. PCPN CHANCES GRADUALLY INCREASE ON THU.
FOR NOW...ANY WINTRY MIX DURING THE DAYLIGHT HOURS WILL BE CONFINED
TO THE HIGHER MTN ELEVATIONS NEAR THE TN LINE.
&&
.LONG TERM /FRIDAY THROUGH MONDAY/...
AS OF 230 PM EST MONDAY...THE MEDIUM RANGE MODEL GUIDANCE HAS SHOWN
SOME IMPROVED RUN-TO-RUN CONSISTENCY AND CONSENSUS WITH REGARD TO
MOVING A DEAMPLIFYING UPPER LOW EASTWARD ACROSS THE WESTERN
CAROLINAS THURSDAY EVENING. THE 00Z ECMWF AND 12Z GFS WERE IN
GENERAL AGREEMENT WITH THE BEST FORCING MOVING MAINLY ACROSS THE NE
GEORGIA AND UPSTATE SC PART OF THE FCST AREA EARLY THURSDAY
EVENING...SO CONFIDENCE IS INCREASING THAT WE WILL SEE SOME PRECIP
THURSDAY EVENING. HOWEVER...THAT THOUGHT IS TEMPERED BY A LOOK AT
THE 12Z ECMWF WHICH KEEPS THE BETTER PRECIP TO THE SOUTH AND EAST OF
UPSTATE SC THURSDAY EVENING. THAT IS A GOOD INDICATOR OF OUR
CONFIDENCE PROBLEM GOING FORWARD WITH THIS FCST. EVEN THE FARTHER
SOUTH NEW ECMWF WOULD BRING MEASURABLE PRECIP OVER THE SRN HALF...SO
PRECIP CHANCES WERE ALLOWED INTO TO THE LIKELY CATEGORY MOST PLACES
ALONG AND S OF I-85...WITH CHANCES ELSEWHERE. THE PRECIP WILL BE
RELATIVELY SHORT LIVED AS THE FORCING MOVES QUICKLY EAST OF THE FCST
AREA BY AROUND DAYBREAK FRIDAY...ASSUMING THIS TIMING HOLDS...WHICH
IS A BIG ASSUMPTION. PRECIP TYPE IS THE MAIN CONCERN...BASED ON A
CONSIDERATION OF PARTIAL THICKNESS ON BOTH MODELS. THE FCST LARGELY
FOLLOWED THE GFS AND ITS THERMAL PROFILES FOR P-TYPE DETERMINATION.
THAT SAID...THERE IS NOT MUCH OF A WARM NOSE...SO IT LOOKS MAINLY
LIKE A RAIN OR SNOW PROSPECT FOR THURSDAY EVENING. LOW LEVELS AND
MIN TEMPS LOOK LIKE THEY WILL REMAIN TOO WARM OVER UPSTATE SC AND NE
GEORGIA FOR ANYTHING BUT A COLD RAIN. OVER THE MTNS...SNOW LEVELS
SHOULD DROP DOWN TO THE VALLEY FLOORS OVERNIGHT. THE PRECIP AMTS ON
THE GFS WOULD SUPPORT A LIGHT ACCUMULATION OF SNOW OVER MAINLY THE
CENTRAL AND NRN MTNS...BUT THERE REMAINS MUCH UNCERTAINTY AS TO QPF.
MOST OF THE NC PART E OF THE BLUE RIDGE WOULD ALSO SEE MAINLY A COLD
RAIN...BUT WITH SOME POTENTIAL FOR BRIEF CHANGEOVER TO SNOW SHOWERS
AS THE PRECIP WAS ENDING. SO FOR NOW...WE LEAVE IT AS A CHANCE OF
SOME WINTRY PRECIP OVER THE MTNS LATE THURSDAY AND THURSDAY NIGHT...
AND WE WATCH MODEL TREND FOR MORE CONSISTENCY.
THE REST OF THE MEDIUM RANGE LOOKS UNEVENTFUL. WE REMAIN DRY
UNDERNEATH A LONG WAVE UPPER TROF...SO HIGH PRESSURE WILL REMAIN IN
CONTROL. HOWEVER...THE REALLY COOL AIR WILL REMAIN TO OUR N...SO
EXPECT TEMPS TO BE FAIRLY CLOSE TO NORMAL.
&&
.AVIATION /06Z TUESDAY THROUGH SATURDAY/...
AT KCLT...VFR CONDITIONS ARE EXPECTED TO REMAIN IN PLACE FOR A TIME
TONIGHT BEFORE WORSENING. A NEARLY STATIONARY FRONT IN THE AREA
CONTINUES TO BE THE FOCUS FOR RAINFALL EASILY PRODUCING MVFR VSBY AS
WELL AS CIGS AS LOW AS LIFR. THIS FRONT WILL GRADUALLY SAG SOUTHWARD
LATE TONIGHT...WHICH INCREASES THE LIKELIHOOD OF SEEING
RESTRICTIONS. FURTHERMORE...LOW CLOUDS MAY ADVECT IN FROM SC/GA
FOLLOWING THE DEEP SOUTHWEST FLOW ALOFT. HAVE TAKEN THE SITE TO LOW
MVFR FOR THE EARLY MORNING HOURS BUT WILL BE CLOSELY WATCHING FOR
NEARBY IFR. MOST OF THE RAIN APPEARS TO BE NORTH OF THE FRONTAL ZONE
SO HAVE REMOVED PREVAILING RA FROM OVERNIGHT PERIOD. HOWEVER RAIN IS
CERTAINLY NOT OUT OF THE QUESTION AND ADDITIONAL RESTRICTIONS COULD
ACCOMPANY ANY RAIN. GUIDANCE INDICATIVE OF LOWERING CIGS TUE EVENING
TOO SO HAVE BROUGHT CATEGORY DOWN TO IFR AT THAT TIME. WITH THE
FRONTAL BOUNDARY STRADDLING THE AREA AND POSSIBLY WAVERING BACK AND
FORTH...IT IS DIFFICULT TO CONFIDENTLY NAIL THE TIMING OF WIND SHIFT
/OR SHIFTS/. HAVE TENTATIVELY GONE IN THE NAM/S FAVOR AND MAINTAINED
SOUTHERLY WINDS THROUGH THE NIGHT BEFORE GOING CALM NEAR
DAYBREAK...WITH NORTHERLY WINDS SETTLING IN THEREAFTER.
ELSEWHERE...MUCH LIKE KCLT RESTRICTIONS WILL BE WIDESPREAD AROUND
THE SITES WITH THE LINGERING FRONTAL BOUNDARY. FAVORED A LAMP/RAP
BLEND FOR CIG HEIGHTS OVERNIGHT DUE TO THEIR HANDLING OF CURRENT
CONDITIONS...THEN FAVORED A LAMP/MAV BLEND TOMORROW AS THE RUC PINS
THE CIGS TOO CLOSELY TO PRECIP DISTRIBUTION. GENERALLY MVFR CIGS
WILL LOWER TO IFR AT MOST SITES TONIGHT INTO EARLY TUE...WITH MVFR
RETURNING FOR MUCH OF THE DAYTIME HOURS. SOME GUIDANCE EVEN TAKES
SOUTHERN SITES BACK TO VFR PERIODICALLY TUE AFTN. HOWEVER THERE IS A
STRONG SIGNAL FROM GUIDANCE THAT IFR WILL RETURN FOR TUE NIGHT. THE
FRONTAL BOUNDARY WILL GRADUALLY MOVE SOUTHWARD DURING THE PERIOD
WHICH SUGGESTS COOLER AIR WILL MOVE IN...LEADING TO COOLER NEAR SFC
AIR THAT COULD HELP PRODUCE STRATUS AND/OR FOG GIVEN THE MOIST SOILS
AND AIR. WINDS WILL BE NORTH TO NORTHEAST ON THE NORTH SIDE OF THE
FRONT AND SOUTH TO SOUTHWEST ON THE SOUTH SIDE. TIMING/POSITIONING
OF THE BOUNDARY DIFFERS BETWEEN MAJOR MODELS AND I HAVE FAIRLY LOW
CONFIDENCE IN WIND FCST...BUT IN GENERAL THE NORTHERN SITES WILL SEE
WINDS SHIFT EARLIEST AS THE FRONT WILL SLOWLY BE MOVING SOUTH
THROUGH THE TAF PERIOD. KHKY LOOKS TO BE THE ONLY SITE WHICH WILL
REMAIN OUT OF A REASONABLY CONSTANT DIRECTION THROUGH 06Z WED.
OUTLOOK...RAIN AND RESTRICTIONS WILL REMAIN WIDESPREAD THROUGH
TUESDAY NIGHT. GRADUAL DRYING IS EXPECTED STARTING WED AND
CONTINUING INTO THU WITH CONDITIONS BECOMING VFR ON WED. A LOW
PRESSURE SYSTEM MOVING ALONG THE GULF COAST LATE IN THE WEEK WILL
SPREAD PRECIP AND RESTRICTIONS BACK INTO THE AREA THU NIGHT THROUGH
FRI.
AN EXPERIMENTAL AVIATION FORECAST CONSISTENCY TABLE SHOWING THE
PERCENTAGE OF GUIDANCE MEMBERS AGREEING WITH THE SCHEDULED ISSUANCE
CATEGORY IS AVAILABLE AT THE FOLLOWING LINK (USE LOWER CASE)...
WWW.WEATHER.GOV/GSP/AVIATION_TABLES
&&
.GSP WATCHES/WARNINGS/ADVISORIES...
GA...FLOOD WATCH THROUGH WEDNESDAY MORNING FOR GAZ010.
NC...FLOOD WATCH THROUGH WEDNESDAY MORNING FOR NCZ048-051-052-058-
059-062.
SC...NONE.
&&
$$
SYNOPSIS...SBK
NEAR TERM...JOH/LG
SHORT TERM...MCAVOY
LONG TERM...PM
AVIATION...WIMBERLEY
AREA FORECAST DISCUSSION FOR WESTERN SD AND NORTHEASTERN WY
NWS RAPID CITY SD
250 PM MST TUE JAN 15 2013
.DISCUSSION...VIGOROUS DEEP LAYER WAA AND HEIGHT RISES ONGOING
ACROSS THE FA...WITH UPSLOPE ENHANCEMENT BEGINING TO REV UP. POTENT
UPPER LEVEL RIDGING AND ASSOCIATED WAA WILL CONTINUE THROUGH MOST OF
THE PERIOD...ALTHOUGH A PASSING NORTHERN STREAM DISTURBANCE WILL
OFFER A SHORT LULL IN WAA ACROSS THE NORTHERN HALF OF THE FA
WED...WITH WAA BEGINNING TO SPREAD OVER THE REGION AGAIN WED NIGHT
THUR AS THE REGION REMAINS ON THE WARM SIDE OF A VERY STRONG
BAROCLINIC ZONE. NEAR SATURATED WAA WILL CONTINUE THROUGH THIS
EVENING...BEFORE DRIER AIR ADVECTS INTO THE FA...SUPPORTING AN END
TO UPGLIDE/UPSLOPE INDUCED SNOW.
STRONG LOW CENTERED OMEGA MAX IS OFFERING STAUNCH LOW LEVEL LIFT IN
A NEAR SATURATED BL...WITH A RISING FROUDE NUMBER IN THE NORTHERN
BLACK HILLS. RAP POINT SOUNDINGS IN FAR WESTERN LAWRENCE COUNTY
INDICATE A DEEPLY SATURATED BL. HOWEVER...WAA IS SHUNTING THE LAYER
OF MAXIMUM OMEGA OUT OF THE DGZ INTO INCREASINGLY WARMER AIR. THIS
HAS ALLOWED THE PRODUCTION OF FREEZING DRIZZLE AT TIMES...WHICH IS
EXPECTED TO MIX WITH UPSLOPE SNOWS THROUGH THE AFTERNOON/EVENING..AS
LL PROFILES WARM AND MID LEVEL DRYING COMMENCES. SNOW MAY MIX WITH
OR CHANGE OVER TO ALL FREEZING DRIZZLE AT TIMES...ESP WITH
OSCILLATING INTENSITY OF UPSLOPE ENHANCEMENT AND ANY SEEDER-FEEDER
PROCESS. STILL EXPECT ANOTHER 1-3 INCHES THROUGH THE EVENING IN TH
ADV...WITH LOCALLY HIGHER AMOUNTS WHERE SNOW PERSISTS...ALTHOUGH ZL
MIXING MAY LIMIT SNOWS SIG IN SOME AREAS. WILL KEEP THE ADV GOING
THROUGH THE CURRENT EXPIRATION TIME.
BREEZY CONDITIONS CAN BE EXPECTED THROUGH WED GIVEN THE LL BAROCLINIC
ZONE IN PLACE ACROSS THE REGION/EXPECTED PRESSURE FALLS...ALTHOUGH
WAA WILL OFFSET THE INTENSITY OF WINDS TONIGHT. A LITTLE BETTER
MIXING AND WEAK CAA ACROSS THE NORTH WILL ALLOW FOR BREEZY
CONDITIONS OVER THE SD PLAINS ON WED.
DRIER AIR WILL WORK INTO THE AREA...WITH SIG AMOUNTS OF HIGH CLOUDS
EXPECTED TO REMAIN GIVEN THE LOCATION OF THE UPPER JET. IN
ADDITION...A WEAK SECONDARY COLD FRONT/TROUGH WILL ADVECT THROUGH
THE AREA...SUPPORTING SOME MID CLOUD ACROSS THE NORTH...WITH
DECREASING CLOUDS THROUGH THE WED PERIOD. ALTHOUGH VERY WARM
PROFILES ARE PROGGED JUST ABOVE THE SFC...HIGH CLOUD COVER MAY LIMIT
T RISES TO A POINT WED...ESP AWAY FROM DOWNSLOPE AREAS AND WHERE A
DEEPER SNOW PACK IS IN PLACE. LOWS WILL REMAIN TRICKY...ESP WED
NIGHT WHEN WAA AND A LINGERING PRESSURE GRADIENT IN PLACE IS
ALLOWING SOME MODEL PROGS TO FORECAST MUCH WARMER TEMPS THAN SOME
OTHER SOLUTIONS. HAVE SIDED SOME TOWARD THIS WARMER SOLUTION WHICH
HAS BEEN EVIDENT THE LAST SEVERAL RUNS...ALTHOUGH QUESTIONS ON SNOW
COVER AND DECOUPLING REMAIN. HAVE INCORPORATED SOME DOWNSLOPE
EFFECTS ON THUR/S HIGHS WHICH WILL AGAIN REMAIN TRICKY.
EXTENDED...FAST NORTHWEST FLOW WILL CONTINUE OVER THE NORTHERN
PLAINS THROUGH EARLY NEXT WEEK. THE FORECAST AREA WILL REMAIN UNDER
THE INFLUENCE OF THE WESTERN RIDGE FOR ONE MORE DAY ON FRIDAY...WITH
DRY CONDITIONS AND MILD TEMPERATURES. CHANGES WILL COME THIS WEEKEND
AS A COMPACT SHORTWAVE DIVES THROUGH NORTHERN MINNESOTA...DRAGGING A
STRONG COLD FRONT ACROSS THE DAKOTAS FRIDAY NIGHT INTO SATURDAY.
TEMPERATURES WILL COOL DRAMATICALLY BY SUNDAY AND MONDAY AS ARCTIC
AIR SETTLES ACROSS THE NORTHERN PLAINS. ANOTHER WEAKER SHORTWAVE
WILL CROSS THE DAKOTAS ON SUNDAY...GIVING THE AREA A CHANCE FOR
LIGHT SNOW THROUGH SUNDAY NIGHT.
&&
.AVIATION...18Z TAF UPDATE
IFR/LIFR CIGS/VIS IN SNOW WILL CONTINUE OVER NERN WY INTO THE BLKHLS
AND NWRN SD THROUGH THIS EVENING. SOME FREEZING DRIZZLE WILL BE
POSSIBLE OVER THE NORTHERN BLACK HILLS. ACROSS THE SD PLAINS...MVFR
CIGS ARE ALSO EXPECTED TO CONTINUE THROUGH THIS EVENING...WITH AREAS
OF IFR VIS EXPECTED IN AREAS OF SNOW. CONDITIONS WILL IMPROVE LATE
TONIGHT FROM WEST TO EAST AS SNOW ENDS.
&&
.UNR WATCHES/WARNINGS/ADVISORIES...
SD...WINTER WEATHER ADVISORY UNTIL 11 PM MST THIS EVENING FOR CENTRAL
BLACK HILLS-NORTHERN BLACK HILLS.
WY...WINTER WEATHER ADVISORY UNTIL 11 PM MST THIS EVENING FOR WYOMING
BLACK HILLS.
&&
$$
SHORT TERM...JC
EXTENDED...15
AVIATION...15
AREA FORECAST DISCUSSION...UPDATED
NWS FORT WORTH TX
1154 AM CST TUE JAN 15 2013
.UPDATE...
DRIZZLE CONTINUES ALONG AN AXIS FROM BOSQUE COUNTY TO ELLIS AND
NAVARRO COUNTIES...EXTENDING TO OUR EASTERN ZONES. TEMPERATURES
HAVE BEEN VERY SLOW TO WARM WHERE DRIZZLE IS OCCURRING AND TEMPS
IN THIS REGION REMAIN AROUND 32 DEGREES. HAVE EXTENDED THE
ADVISORY UNTIL 2 PM FOR THESE LOCATIONS AND WILL LET THE REST OF
THE ADVISORY EXPIRE. INCLUDED DALLAS COUNTY IN THE EXTENSION
BECAUSE LANCASTER AND MESQUITE ARE AT 32 DEGREES WITH FREEZING
DRIZZLE...SO THE MAIN IMPACTS WILL BE CONFINED TO THE EXTREME
SOUTHEASTERN PORTIONS OF DALLAS COUNTY. TEMPERATURES SHOULD BE
ABOVE FREEZING BETWEEN 1 AND 2 PM.
HAMPSHIRE
&&
.AVIATION...
CIGS ACROSS THE METROPLEX TAF SITES ARE GENERALLY VFR OR ARE IN THE
PROCESS OF LIFTING TO VFR SHORTLY. MAIN AREA OF DRIZZLE AND
FREEZING DRIZZLE IS TO THE SOUTH OF TAF SITES AND SHOULD REMAIN
THERE. THEREFORE NOT EXPECTING ANY ADDITIONAL WINTER ISSUES AT TAF
SITES...AND A DRY FORECAST WITH NO CONCERNS IS EXPECTED TONIGHT
AND TOMORROW. CIGS WILL CONTINUE TO LIFT DURING THE AFTERNOON AND
OVERNIGHT HOURS AS DRIER AIR MOVES INTO THE AREA. WINDS WILL BE
NORTH NEAR 10KT BECOMING WEST TONIGHT.
FOR WACO...IFR CIGS WILL GRADUALLY LIFT DURING THE AFTERNOON HOURS
TO MVFR...AND VFR IS EXPECTED BY SUNSET. LIGHT DRIZZLE OR MIST IS
OCCURRING NOW...BUT SHOULD TAPER OFF BY MID AFTERNOON. NORTH WINDS
AT 10 KT WILL BECOME WEST BY MORNING.
TR.92
&&
.PREV UPDATE...
.UPDATE...
LATEST ISENTROPIC PLOTS FROM THE RAP CONTINUE TO SHOW WEAK UPGLIDE
THROUGH 700 MB PERSISTING FOR MOST OF THE MORNING AND EARLY
AFTERNOON. FORECAST SOUNDINGS DEPICT DRYING IN THE UPPER LEVELS OF
THE ATMOSPHERE AND THIS WEAK LIFT WOULD BE SUPPORTIVE OF DRIZZLE.
STARTING TO SEE LIGHT RETURNS WEST OF INTERSTATE 35...BUT NOTHING
HAS BEEN REPORTED YET AT ANY OF THE AREA OBSERVATION SITES. NOT
MUCH PRECIP FELL IN THESE LOCATIONS AND AS THIS WEAK LIFT IN THE
LOWEST ATMOSPHERE SHIFTS EAST...DRIZZLE IS LIKELY TO FORM ACROSS
THE AREA WHICH PICKED UP OVERNIGHT PRECIP. LATEST RAP ALSO KEEPS
TEMPERATURES BELOW FREEZING UNTIL NOON OR 1 PM...AND WE EXTENDED
THE ADVISORY UNTIL NOON. THE FREEZING DRIZZLE WOULD BE PROBLEMATIC
AS THIS WOULD FALL ON TOP OF THE SLEET/SNOW AND MAKE THE AREA
BRIDGES AND OVERPASSES EVEN MORE HAZARDOUS.
HAMPSHIRE
&&
.PREV DISCUSSION... /ISSUED 448 AM CST TUE JAN 15 2013/
SHORT TERM WINTER WEATHER CONCERNS...
ONCE AGAIN WE HAVE A THREAT FOR WINTRY PRECIPITATION TO DEVELOP
OVER PORTIONS OF NORTH AND CENTRAL TX EARLY THIS MORNING. THE LONG
WAVE TROUGH OVER THE WESTERN CONUS HAS BECOME POSITIVELY TILTED
ALREADY THIS MORNING AND ITS AXIS NOW ORIENTED FROM NORTHERN
MINNESOTA SOUTHWEST TO THE SOUTHERN NEW MEXICO AND ARIZONA BORDER.
THE TROUGH WAS SHOWING SIGNS OF MOVING EAST ALREADY EARLY THIS
MORNING. THIS EASTWARD MOVEMENT...COMBINED WITH A COMPACT
SHORTWAVE TROUGH EMBEDDED IN THE SOUTHWEST FLOW ALOFT OVER THE
SOUTHERN HIGH PLAINS IS LIKELY PROVIDING THE LARGE SCALE FORCING
FOR ASCENT EVIDENT ON WATER VAPOR IMAGERY OVER NORTH TX AT THIS
TIME. EVIDENCE OF LARGE SCALE FORCING FOR ASCENT WAS SHOWING UP IN
IR SATELLITE IMAGERY AND VWP PROFILES EARLY THIS MORNING AS WELL.
IR SATELLITE IMAGERY INDICATES COOLING CLOUD TOPS OVER MUCH OF
NORTH AND CENTRAL TX WHILE REGIONAL RADAR VWP SHOWS LOW LEVEL FLOW
VEERING STRONGLY WITH HEIGHT...A SIGN OF WARM AIR ADVECTION AND
ISENTROPIC LIFT. ALL OF THIS IS EVIDENCE THAT WE WILL LIKELY SEE
RADAR RETURNS BLOSSOM AROUND NORTH AND CENTRAL TX THIS MORNING AS
PERSISTENT ASCENT EVENTUALLY RESULTS IN SCATTERED PRECIPITATION
DEVELOP OVER THE REGION.
CONFIDENCE IS FAIRLY HIGH THAT PRECIPITATION WILL DEVELOP OVER
MOST AREAS ALONG AND SOUTHEAST OF A BONHAM TO FORT WORTH TO
LAMPASAS LINE EARLY THIS MORNING. AS A RESULT WENT AHEAD AND
BUMPED UP POPS INTO THE 30 TO 50 PERCENT RANGE FOR THESE LOCATIONS
THROUGH THE MORNING HOURS. CONFIDENCE WAVERS WHEN DETERMINING WHAT
FORM THIS PRECIPITATION WILL FALL AS IT DEVELOPS AND MOVES
NORTHEAST OVER THESE LOCATIONS. THERE ARE SEVERAL FACTORS TO
CONSIDER...AND ILL DETAIL SOME OF THOSE BELOW.
THE EASIEST THING TO NOTICE IS THAT SURFACE TEMPERATURES ARE A
GOOD 5 DEGREES WARMER THAN EXPECTED TO START OFF THE FORECAST
TODAY. THIS IS ONE GOOD CONSEQUENCE OF THE MODELS UNDERESTIMATING
THE STRENGTH OF LARGE SCALE FORCING FOR ASCENT OVER THE
REGION...CLOUDS BUILT IN EARLIER THAN EXPECTED WHICH PREVENTED
TEMPERATURES FROM FALLING BELOW FREEZING SOUTH OF INTERSTATE
20...AT LEAST AS OF 4 AM CST. THIS AT LEAST ALLEVIATES CONCERNS
FOR FREEZING RAIN OVER THE WACO/KILLEEN/TEMPLE AREAS EARLY THIS
MORNING.
FURTHER NORTH...PRECIPITATION IS EXPECTED TO DEVELOP AROUND OR
AFTER 5 AM CST NEAR THE DFW METROPLEX...WHILE 4 AM SURFACE
OBSERVATIONS INDICATED THAT THE WET BULB ZERO LINE WAS LOCATED AS
FAR SOUTH AS CLEBURNE AND WAXAHACHIE. 05Z AMDAR AIRCRAFT SOUNDINGS
INDICATED THAT THE THERMAL PROFILE OVER THE METROPLEX WAS MOSTLY
SUPPORTIVE OF SNOW...WITH A SURFACE TO 700 MB ISOTHERMAL LAYER
HUGGING THE 0 DEG C LINE. THIS OBSERVATION WAS TAKEN FROM AIRCRAFT
BEFORE THE STRONGER LARGE SCALE FORCING FOR ASCENT BUILT OVER THE
AREA...WHICH SHOULD ONLY RESULT IN COOLING ALOFT. AS A RESULT WENT
AHEAD AND ISSUED A WINTER WEATHER ADVISORY FOR THE DFW METROPLEX
AND LOCATIONS TO THE EAST AND NORTHEAST AS THESE LOCATIONS ARE THE
MOST LIKELY TO SEE LIGHT ACCUMULATIONS OF SNOW WITH SOME SLEET
MIXED IN THIS MORNING.
IN TERMS OF AMOUNTS...SNOW OR SLEET AMOUNTS ARE EXPECTED TO VARY
WITHIN THE ADVISORY FROM TRACE AMOUNTS UP TO ONE HALF INCH. THE
VARIATION IS BECAUSE MOST PRECIPITATION IS EXPECTED TO DEVELOP IN
A BANDED FORM WHICH MEANS LOCATIONS WITHIN SNOW BANDS WILL LIKELY
SEE WINTRY PRECIPITATION ACCUMULATE...WHILE THOSE AREAS NOT
INCLUDED IN BANDS MAY SEE LIGHT PRECIPITATION...OR NOTHING AT ALL.
BANDED PRECIPITATION IS FAVORED BECAUSE THE GFS AND NAM BOTH
INDICATE THAT PRECIPITATION IN THE WINTER WEATHER ADVISORY AREA
WILL BE ENHANCED BY FRONTOGENETIC FORCING...MAXIMIZED IN THE H800
TO H700 LAYER. ABOVE 700 MB...BOTH MODELS ALSO INDICATE A
RELATIVELY DEEP LAYER OF NEGATIVE SATURATED EPV (EQUIVALENT
GEOSTROPHIC POTENTIAL VORTICITY) WHICH INDICATES THAT VERTICAL
MOTIONS INITIATED AT THE BOTTOM OF THIS LAYER WILL RESULT IN A
RELEASE OF EITHER CONVECTIVE OR SLANTWISE INSTABILITY. THERE IS A
SHALLOW LAYER OF THETA-E TEMPERATURE DECREASE WITH HEIGHT WITHIN
THIS LAYER...SO A MIX OF CELLULAR AND BANDED PRECIPITATION IS
LIKELY TO OCCUR. EITHER WAY...THIS TYPE OF FORCING AND INSTABILITY
COMBINATION OFTEN FAVORS LARGE GRADIENTS OF WINTRY ACCUMULATION
AND THAT IS WHAT IS EXPECTED ACROSS NORTH TX THIS MORNING.
IN TERMS OF IMPACTS...WENT AHEAD WITH THE WINTER WEATHER ADVISORY
WITHOUT 100 PERCENT CONFIDENCE THAT LOCATIONS IN THE ADVISORY WILL
ALL SEE ACCUMULATING WINTRY PRECIPITATION. THESE ARE SIMPLY THE
AREAS THAT HAVE THE BEST DIAGNOSED COMBINATION OF FORCING AND
MESOSCALE ENHANCEMENTS THIS MORNING. THE ADVISORY WAS ISSUED
BEFORE RADAR RETURNS HAD DEVELOPED OVER THE ADVISORY AREA TO GIVE
EVERYONE WAKING UP EARLY THIS MORNING A HEADS UP ON THE THREAT OF
WINTRY WEATHER IMPACTING THE MORNING COMMUTE. ASSUMING BANDED
WINTRY PRECIPITATION DEVELOPS OVER THE METROPLEX AROUND 5 AM AS
EXPECTED...THIS IS EXPECTED TO HAVE A VERY NEGATIVE IMPACT ON THE
MORNING RUSH HOUR...POSSIBLY CAUSING SIGNIFICANT DELAYS FOR THE
MORNING COMMUTE. BECAUSE TEMPERATURES ARE HOVERING RIGHT AROUND
FREEZING...MOST ROAD SURFACES IN CONTACT WITH THE GROUND SHOULD
SEE MOST SNOW AND SLEET MELT UPON LANDING AS GROUND TEMPERATURES
REMAIN WELL ABOVE FREEZING. BRIDGES AND OVERPASSES HOWEVER ARE
LIKELY TO RETAIN WINTRY ACCUMULATIONS THIS MORNING...RESULTING IN
ICY CONDITIONS ON ELEVATED ROADWAYS...ESPECIALLY AS TRAFFIC DRIVES
OVER IT...COMPACTING ANY ACCUMULATIONS INTO ICE. WINTRY
PRECIPITATION IS EXPECTED TO MOVE NORTHEAST OR DISSIPATE FOR THE
MOST PART AFTER 9 AM CST. LEFT THE ADVISORY GOING THROUGH 10 AM AS
IT MAY TAKE AN HOUR OR SO AFTER WINTRY PRECIPITATION CEASES BEFORE
ROAD CONDITIONS IMPROVE.
REMAINDER OF THE FORECAST...ALL 15/00Z GUIDANCE INDICATES THAT THE
LARGE UPPER TROUGH TO OUR WEST WILL REMAIN POSITIVELY TILTED AS IT
MOVES OVER THE SOUTH PLAINS OVERNIGHT INTO WEDNESDAY MORNING. THIS
WILL RESULT IN SOME LIGHT RAINFALL WEDNESDAY MORNING SOUTHEAST OF A
CANTON TO WACO LINE ASSUMING THE MODELS ARE RESOLVING THIS TROUGHS
EVOLUTION WELL. WITH NO GUIDANCE OFFERING UP THE CLOSED LOW
SOLUTION ANYMORE...DO NOT HAVE ANYTHING IN THE FORECAST TO HANDLE
THIS NOW UNLIKELY ALTERNATIVE SCENARIO. IT SEEMS THAT AFTER THIS
MORNINGS COMPACT SHORTWAVE TROUGH MOVES NORTHEAST...THE LOWER
TROPOSPHERE WILL BECOME DOMINATED ONCE AGAIN BY COLD AIR ADVECTION
WHICH WOULD SERVE TO KEEP THE TROUGH POSITIVELY TILTED AS IT MOVED
OVER THE CWA. ONE IMPORTANT CAVEAT HERE...WILL HAVE TO SEE HOW
LONG AND INTENSE PRECIPITATION ACTUALLY IS ACROSS NORTH...CENTRAL
AND EAST TX TODAY. IF PRECIPITATION HANGS AROUND LONGER THAN
EXPECTED OR IS JUST MORE INTENSE THAN EXPECTED...PRECIPITATION
WILL RELEASE MORE LATENT HEAT INTO THE MIDDLE TROPOSPHERE THAN THE
MODELS WERE PLANNING ON. WITH NO GUIDANCE FAVORING THE CUT-OFF LOW
SOLUTION ANYMORE...ITS HARD TO IMAGINE WE GET ENOUGH LATENT HEAT
RELEASE TO RAISE THICKNESSES ENOUGH DOWNSTREAM TO HAVE AN IMPACT
ON THE TILT OF THIS TROUGH. HOWEVER IT IS THE ONE THING TO WATCH
FOR DURING THE DAY TODAY...IF DEVELOPING PRECIPITATION RESULTS IN
RIDGING OVER EAST TX...THE UPPER CLOUD COULD MAKE AN ATTEMPT AT
BECOMING NEUTRALLY TILTED OR CUTTING OFF AS IT MOVES TOWARDS THE
CWA OVER THE NEXT 24 HRS. WHILE UNLIKELY...WE WILL NEED TO WATCH
FOR THIS JUST IN CASE THE MODELS HAVE MISSED SOMETHING IMPORTANT
HERE.
THURSDAY AND BEYOND...ONCE THIS UPPER TROUGH MOVES EAST OF THE
SOUTH PLAINS...WE WILL MAINTAIN A DRY FORECAST THROUGH EARLY NEXT
WEEK. TEMPERATURES WILL SLOWLY MODERATE BEHIND THE TROUGH...WITH
HIGHS MAKING A RUN AT 60 DEGREES BY SATURDAY AFTERNOON. WE ARE
STILL LOOKING AT A STRONG COLD FRONT TO KICK OFF THE UPCOMING WORK
WEEK. THE ECMWF IS BACK TO INDICATING A FAIRLY ROBUST PUNCH OF DRY
ARCTIC AIR WHILE THE GFS CONTINUES TO ADVERTISE A COOL BUT
MODIFIED AIRMASS SINKING SOUTH THROUGH THE PLAINS. WENT AHEAD WITH
THE COLDER END OF THE SPECTRUM OF AVAILABLE GUIDANCE BUT MAY HAVE
TO GO EVEN LOWER WITH TEMPS IF THE ECMWF VERIFIES.
CAVANAUGH
&&
.PRELIMINARY POINT TEMPS/POPS...
DALLAS-FT. WORTH, TX 35 27 50 33 53 / 60 10 10 10 0
WACO, TX 35 27 51 30 55 / 50 10 20 10 0
PARIS, TX 34 25 46 29 51 / 60 10 10 10 0
DENTON, TX 36 26 49 29 51 / 60 10 10 10 0
MCKINNEY, TX 35 26 47 29 51 / 60 10 10 10 0
DALLAS, TX 37 28 51 34 53 / 60 10 10 10 0
TERRELL, TX 35 26 48 30 53 / 60 10 10 10 0
CORSICANA, TX 34 28 49 31 54 / 50 10 20 10 0
TEMPLE, TX 35 28 50 30 54 / 40 10 20 10 0
MINERAL WELLS, TX 37 24 52 28 55 / 30 10 10 10 0
&&
.FWD WATCHES/WARNINGS/ADVISORIES...
WINTER WEATHER ADVISORY UNTIL 2 PM CST THIS AFTERNOON FOR
TXZ105>107-119>123-133>135-144>146.
WINTER WEATHER ADVISORY UNTIL NOON CST TODAY FOR TXZ092>095-
102>104-117-118-130>132-148.
&&
$$
85/85
AREA FORECAST DISCUSSION
NWS FORT WORTH TX
1144 AM CST TUE JAN 15 2013
.AVIATION...
CIGS ACROSS THE METROPLEX TAF SITES ARE GENERALLY VFR OR ARE IN THE
PROCESS OF LIFTING TO VFR SHORTLY. MAIN AREA OF DRIZZLE AND
FREEZING DRIZZLE IS TO THE SOUTH OF TAF SITES AND SHOULD REMAIN
THERE. THEREFORE NOT EXPECTING ANY ADDITIONAL WINTER ISSUES AT TAF
SITES...AND A DRY FORECAST WITH NO CONCERNS IS EXPECTED TONIGHT
AND TOMORROW. CIGS WILL CONTINUE TO LIFT DURING THE AFTERNOON AND
OVERNIGHT HOURS AS DRIER AIR MOVES INTO THE AREA. WINDS WILL BE
NORTH NEAR 10KT BECOMING WEST TONIGHT.
FOR WACO...IFR CIGS WILL GRADUALLY LIFT DURING THE AFTERNOON HOURS
TO MVFR...AND VFR IS EXPECTED BY SUNSET. LIGHT DRIZZLE OR MIST IS
OCCURRING NOW...BUT SHOULD TAPER OFF BY MID AFTERNOON. NORTH WINDS
AT 10 KT WILL BECOME WEST BY MORNING.
TR.92
&&
.UPDATE...
LATEST ISENTROPIC PLOTS FROM THE RAP CONTINUE TO SHOW WEAK UPGLIDE
THROUGH 700 MB PERSISTING FOR MOST OF THE MORNING AND EARLY
AFTERNOON. FORECAST SOUNDINGS DEPICT DRYING IN THE UPPER LEVELS OF
THE ATMOSPHERE AND THIS WEAK LIFT WOULD BE SUPPORTIVE OF DRIZZLE.
STARTING TO SEE LIGHT RETURNS WEST OF INTERSTATE 35...BUT NOTHING
HAS BEEN REPORTED YET AT ANY OF THE AREA OBSERVATION SITES. NOT
MUCH PRECIP FELL IN THESE LOCATIONS AND AS THIS WEAK LIFT IN THE
LOWEST ATMOSPHERE SHIFTS EAST...DRIZZLE IS LIKELY TO FORM ACROSS
THE AREA WHICH PICKED UP OVERNIGHT PRECIP. LATEST RAP ALSO KEEPS
TEMPERATURES BELOW FREEZING UNTIL NOON OR 1 PM...AND WE EXTENDED
THE ADVISORY UNTIL NOON. THE FREEZING DRIZZLE WOULD BE PROBLEMATIC
AS THIS WOULD FALL ON TOP OF THE SLEET/SNOW AND MAKE THE AREA
BRIDGES AND OVERPASSES EVEN MORE HAZARDOUS.
HAMPSHIRE
&&
.PREV DISCUSSION... /ISSUED 448 AM CST TUE JAN 15 2013/
SHORT TERM WINTER WEATHER CONCERNS...
ONCE AGAIN WE HAVE A THREAT FOR WINTRY PRECIPITATION TO DEVELOP
OVER PORTIONS OF NORTH AND CENTRAL TX EARLY THIS MORNING. THE LONG
WAVE TROUGH OVER THE WESTERN CONUS HAS BECOME POSITIVELY TILTED
ALREADY THIS MORNING AND ITS AXIS NOW ORIENTED FROM NORTHERN
MINNESOTA SOUTHWEST TO THE SOUTHERN NEW MEXICO AND ARIZONA BORDER.
THE TROUGH WAS SHOWING SIGNS OF MOVING EAST ALREADY EARLY THIS
MORNING. THIS EASTWARD MOVEMENT...COMBINED WITH A COMPACT
SHORTWAVE TROUGH EMBEDDED IN THE SOUTHWEST FLOW ALOFT OVER THE
SOUTHERN HIGH PLAINS IS LIKELY PROVIDING THE LARGE SCALE FORCING
FOR ASCENT EVIDENT ON WATER VAPOR IMAGERY OVER NORTH TX AT THIS
TIME. EVIDENCE OF LARGE SCALE FORCING FOR ASCENT WAS SHOWING UP IN
IR SATELLITE IMAGERY AND VWP PROFILES EARLY THIS MORNING AS WELL.
IR SATELLITE IMAGERY INDICATES COOLING CLOUD TOPS OVER MUCH OF
NORTH AND CENTRAL TX WHILE REGIONAL RADAR VWP SHOWS LOW LEVEL FLOW
VEERING STRONGLY WITH HEIGHT...A SIGN OF WARM AIR ADVECTION AND
ISENTROPIC LIFT. ALL OF THIS IS EVIDENCE THAT WE WILL LIKELY SEE
RADAR RETURNS BLOSSOM AROUND NORTH AND CENTRAL TX THIS MORNING AS
PERSISTENT ASCENT EVENTUALLY RESULTS IN SCATTERED PRECIPITATION
DEVELOP OVER THE REGION.
CONFIDENCE IS FAIRLY HIGH THAT PRECIPITATION WILL DEVELOP OVER
MOST AREAS ALONG AND SOUTHEAST OF A BONHAM TO FORT WORTH TO
LAMPASAS LINE EARLY THIS MORNING. AS A RESULT WENT AHEAD AND
BUMPED UP POPS INTO THE 30 TO 50 PERCENT RANGE FOR THESE LOCATIONS
THROUGH THE MORNING HOURS. CONFIDENCE WAVERS WHEN DETERMINING WHAT
FORM THIS PRECIPITATION WILL FALL AS IT DEVELOPS AND MOVES
NORTHEAST OVER THESE LOCATIONS. THERE ARE SEVERAL FACTORS TO
CONSIDER...AND ILL DETAIL SOME OF THOSE BELOW.
THE EASIEST THING TO NOTICE IS THAT SURFACE TEMPERATURES ARE A
GOOD 5 DEGREES WARMER THAN EXPECTED TO START OFF THE FORECAST
TODAY. THIS IS ONE GOOD CONSEQUENCE OF THE MODELS UNDERESTIMATING
THE STRENGTH OF LARGE SCALE FORCING FOR ASCENT OVER THE
REGION...CLOUDS BUILT IN EARLIER THAN EXPECTED WHICH PREVENTED
TEMPERATURES FROM FALLING BELOW FREEZING SOUTH OF INTERSTATE
20...AT LEAST AS OF 4 AM CST. THIS AT LEAST ALLEVIATES CONCERNS
FOR FREEZING RAIN OVER THE WACO/KILLEEN/TEMPLE AREAS EARLY THIS
MORNING.
FURTHER NORTH...PRECIPITATION IS EXPECTED TO DEVELOP AROUND OR
AFTER 5 AM CST NEAR THE DFW METROPLEX...WHILE 4 AM SURFACE
OBSERVATIONS INDICATED THAT THE WET BULB ZERO LINE WAS LOCATED AS
FAR SOUTH AS CLEBURNE AND WAXAHACHIE. 05Z AMDAR AIRCRAFT SOUNDINGS
INDICATED THAT THE THERMAL PROFILE OVER THE METROPLEX WAS MOSTLY
SUPPORTIVE OF SNOW...WITH A SURFACE TO 700 MB ISOTHERMAL LAYER
HUGGING THE 0 DEG C LINE. THIS OBSERVATION WAS TAKEN FROM AIRCRAFT
BEFORE THE STRONGER LARGE SCALE FORCING FOR ASCENT BUILT OVER THE
AREA...WHICH SHOULD ONLY RESULT IN COOLING ALOFT. AS A RESULT WENT
AHEAD AND ISSUED A WINTER WEATHER ADVISORY FOR THE DFW METROPLEX
AND LOCATIONS TO THE EAST AND NORTHEAST AS THESE LOCATIONS ARE THE
MOST LIKELY TO SEE LIGHT ACCUMULATIONS OF SNOW WITH SOME SLEET
MIXED IN THIS MORNING.
IN TERMS OF AMOUNTS...SNOW OR SLEET AMOUNTS ARE EXPECTED TO VARY
WITHIN THE ADVISORY FROM TRACE AMOUNTS UP TO ONE HALF INCH. THE
VARIATION IS BECAUSE MOST PRECIPITATION IS EXPECTED TO DEVELOP IN
A BANDED FORM WHICH MEANS LOCATIONS WITHIN SNOW BANDS WILL LIKELY
SEE WINTRY PRECIPITATION ACCUMULATE...WHILE THOSE AREAS NOT
INCLUDED IN BANDS MAY SEE LIGHT PRECIPITATION...OR NOTHING AT ALL.
BANDED PRECIPITATION IS FAVORED BECAUSE THE GFS AND NAM BOTH
INDICATE THAT PRECIPITATION IN THE WINTER WEATHER ADVISORY AREA
WILL BE ENHANCED BY FRONTOGENETIC FORCING...MAXIMIZED IN THE H800
TO H700 LAYER. ABOVE 700 MB...BOTH MODELS ALSO INDICATE A
RELATIVELY DEEP LAYER OF NEGATIVE SATURATED EPV (EQUIVALENT
GEOSTROPHIC POTENTIAL VORTICITY) WHICH INDICATES THAT VERTICAL
MOTIONS INITIATED AT THE BOTTOM OF THIS LAYER WILL RESULT IN A
RELEASE OF EITHER CONVECTIVE OR SLANTWISE INSTABILITY. THERE IS A
SHALLOW LAYER OF THETA-E TEMPERATURE DECREASE WITH HEIGHT WITHIN
THIS LAYER...SO A MIX OF CELLULAR AND BANDED PRECIPITATION IS
LIKELY TO OCCUR. EITHER WAY...THIS TYPE OF FORCING AND INSTABILITY
COMBINATION OFTEN FAVORS LARGE GRADIENTS OF WINTRY ACCUMULATION
AND THAT IS WHAT IS EXPECTED ACROSS NORTH TX THIS MORNING.
IN TERMS OF IMPACTS...WENT AHEAD WITH THE WINTER WEATHER ADVISORY
WITHOUT 100 PERCENT CONFIDENCE THAT LOCATIONS IN THE ADVISORY WILL
ALL SEE ACCUMULATING WINTRY PRECIPITATION. THESE ARE SIMPLY THE
AREAS THAT HAVE THE BEST DIAGNOSED COMBINATION OF FORCING AND
MESOSCALE ENHANCEMENTS THIS MORNING. THE ADVISORY WAS ISSUED
BEFORE RADAR RETURNS HAD DEVELOPED OVER THE ADVISORY AREA TO GIVE
EVERYONE WAKING UP EARLY THIS MORNING A HEADS UP ON THE THREAT OF
WINTRY WEATHER IMPACTING THE MORNING COMMUTE. ASSUMING BANDED
WINTRY PRECIPITATION DEVELOPS OVER THE METROPLEX AROUND 5 AM AS
EXPECTED...THIS IS EXPECTED TO HAVE A VERY NEGATIVE IMPACT ON THE
MORNING RUSH HOUR...POSSIBLY CAUSING SIGNIFICANT DELAYS FOR THE
MORNING COMMUTE. BECAUSE TEMPERATURES ARE HOVERING RIGHT AROUND
FREEZING...MOST ROAD SURFACES IN CONTACT WITH THE GROUND SHOULD
SEE MOST SNOW AND SLEET MELT UPON LANDING AS GROUND TEMPERATURES
REMAIN WELL ABOVE FREEZING. BRIDGES AND OVERPASSES HOWEVER ARE
LIKELY TO RETAIN WINTRY ACCUMULATIONS THIS MORNING...RESULTING IN
ICY CONDITIONS ON ELEVATED ROADWAYS...ESPECIALLY AS TRAFFIC DRIVES
OVER IT...COMPACTING ANY ACCUMULATIONS INTO ICE. WINTRY
PRECIPITATION IS EXPECTED TO MOVE NORTHEAST OR DISSIPATE FOR THE
MOST PART AFTER 9 AM CST. LEFT THE ADVISORY GOING THROUGH 10 AM AS
IT MAY TAKE AN HOUR OR SO AFTER WINTRY PRECIPITATION CEASES BEFORE
ROAD CONDITIONS IMPROVE.
REMAINDER OF THE FORECAST...ALL 15/00Z GUIDANCE INDICATES THAT THE
LARGE UPPER TROUGH TO OUR WEST WILL REMAIN POSITIVELY TILTED AS IT
MOVES OVER THE SOUTH PLAINS OVERNIGHT INTO WEDNESDAY MORNING. THIS
WILL RESULT IN SOME LIGHT RAINFALL WEDNESDAY MORNING SOUTHEAST OF A
CANTON TO WACO LINE ASSUMING THE MODELS ARE RESOLVING THIS TROUGHS
EVOLUTION WELL. WITH NO GUIDANCE OFFERING UP THE CLOSED LOW
SOLUTION ANYMORE...DO NOT HAVE ANYTHING IN THE FORECAST TO HANDLE
THIS NOW UNLIKELY ALTERNATIVE SCENARIO. IT SEEMS THAT AFTER THIS
MORNINGS COMPACT SHORTWAVE TROUGH MOVES NORTHEAST...THE LOWER
TROPOSPHERE WILL BECOME DOMINATED ONCE AGAIN BY COLD AIR ADVECTION
WHICH WOULD SERVE TO KEEP THE TROUGH POSITIVELY TILTED AS IT MOVED
OVER THE CWA. ONE IMPORTANT CAVEAT HERE...WILL HAVE TO SEE HOW
LONG AND INTENSE PRECIPITATION ACTUALLY IS ACROSS NORTH...CENTRAL
AND EAST TX TODAY. IF PRECIPITATION HANGS AROUND LONGER THAN
EXPECTED OR IS JUST MORE INTENSE THAN EXPECTED...PRECIPITATION
WILL RELEASE MORE LATENT HEAT INTO THE MIDDLE TROPOSPHERE THAN THE
MODELS WERE PLANNING ON. WITH NO GUIDANCE FAVORING THE CUT-OFF LOW
SOLUTION ANYMORE...ITS HARD TO IMAGINE WE GET ENOUGH LATENT HEAT
RELEASE TO RAISE THICKNESSES ENOUGH DOWNSTREAM TO HAVE AN IMPACT
ON THE TILT OF THIS TROUGH. HOWEVER IT IS THE ONE THING TO WATCH
FOR DURING THE DAY TODAY...IF DEVELOPING PRECIPITATION RESULTS IN
RIDGING OVER EAST TX...THE UPPER CLOUD COULD MAKE AN ATTEMPT AT
BECOMING NEUTRALLY TILTED OR CUTTING OFF AS IT MOVES TOWARDS THE
CWA OVER THE NEXT 24 HRS. WHILE UNLIKELY...WE WILL NEED TO WATCH
FOR THIS JUST IN CASE THE MODELS HAVE MISSED SOMETHING IMPORTANT
HERE.
THURSDAY AND BEYOND...ONCE THIS UPPER TROUGH MOVES EAST OF THE
SOUTH PLAINS...WE WILL MAINTAIN A DRY FORECAST THROUGH EARLY NEXT
WEEK. TEMPERATURES WILL SLOWLY MODERATE BEHIND THE TROUGH...WITH
HIGHS MAKING A RUN AT 60 DEGREES BY SATURDAY AFTERNOON. WE ARE
STILL LOOKING AT A STRONG COLD FRONT TO KICK OFF THE UPCOMING WORK
WEEK. THE ECMWF IS BACK TO INDICATING A FAIRLY ROBUST PUNCH OF DRY
ARCTIC AIR WHILE THE GFS CONTINUES TO ADVERTISE A COOL BUT
MODIFIED AIRMASS SINKING SOUTH THROUGH THE PLAINS. WENT AHEAD WITH
THE COLDER END OF THE SPECTRUM OF AVAILABLE GUIDANCE BUT MAY HAVE
TO GO EVEN LOWER WITH TEMPS IF THE ECMWF VERIFIES.
CAVANAUGH
&&
.PRELIMINARY POINT TEMPS/POPS...
DALLAS-FT. WORTH, TX 36 27 50 33 53 / 60 10 10 10 0
WACO, TX 35 27 51 30 55 / 50 10 20 10 0
PARIS, TX 36 25 46 29 51 / 60 10 10 10 0
DENTON, TX 37 26 49 29 51 / 60 10 10 10 0
MCKINNEY, TX 36 26 47 29 51 / 60 10 10 10 0
DALLAS, TX 35 28 51 34 53 / 60 10 10 10 0
TERRELL, TX 34 26 48 30 53 / 60 10 10 10 0
CORSICANA, TX 34 28 49 31 54 / 50 10 20 10 0
TEMPLE, TX 35 28 50 30 54 / 40 10 20 10 0
MINERAL WELLS, TX 38 24 52 28 55 / 30 10 10 10 0
&&
.FWD WATCHES/WARNINGS/ADVISORIES...
WINTER WEATHER ADVISORY UNTIL NOON CST TODAY FOR TXZ092>095-
102>107-117>123-130>135-144>146-148.
&&
$$
/
AREA FORECAST DISCUSSION...UPDATED
NWS FORT WORTH TX
825 AM CST TUE JAN 15 2013
.UPDATE...
LATEST ISENTROPIC PLOTS FROM THE RAP CONTINUE TO SHOW WEAK UPGLIDE
THROUGH 700 MB PERSISTING FOR MOST OF THE MORNING AND EARLY
AFTERNOON. FORECAST SOUNDINGS DEPICT DRYING IN THE UPPER LEVELS OF
THE ATMOSPHERE AND THIS WEAK LIFT WOULD BE SUPPORTIVE OF DRIZZLE.
STARTING TO SEE LIGHT RETURNS WEST OF INTERSTATE 35...BUT NOTHING
HAS BEEN REPORTED YET AT ANY OF THE AREA OBSERVATION SITES. NOT
MUCH PRECIP FELL IN THESE LOCATIONS AND AS THIS WEAK LIFT IN THE
LOWEST ATMOSPHERE SHIFTS EAST...DRIZZLE IS LIKELY TO FORM ACROSS
THE AREA WHICH PICKED UP OVERNIGHT PRECIP. LATEST RAP ALSO KEEPS
TEMPERATURES BELOW FREEZING UNTIL NOON OR 1 PM...AND WE EXTENDED
THE ADVISORY UNTIL NOON. THE FREEZING DRIZZLE WOULD BE PROBLEMATIC
AS THIS WOULD FALL ON TOP OF THE SLEET/SNOW AND MAKE THE AREA
BRIDGES AND OVERPASSES EVEN MORE HAZARDOUS.
HAMPSHIRE
&&
.AVIATION...
KDFW AIRPORT WEATHER WARNING UNTIL 1600UTC /10AM CST/ FOR A WINTRY
MIX AND LIGHT ICE ACCUMULATION.
FOR ALL NORTH TEXAS TAF SITES...A MIX BAG OF WINTRY PRECIPITATION WILL
CONTINUE TO INCREASE IN COVERAGE AND INTENSITY OVER THE NEXT
SEVERAL HOURS. MOVEMENT OF THE ACTIVITY IS NORTHEAST AT 50-55
KNOTS. ICE ACCUMULATION UP TO 1/10 OF AN INCH IS POSSIBLE ON
BEFORE ENDING LATE MORNING.
CIGS AND VIS ARE COMING DOWN TO WITHIN THE PRECIPITATION. DURING
HEAVIER OUTBURST OF SLEET AND SNOW PELLETS...VIS MAY FALL TO
1-2SM AND CIGS DOWN TO AROUND 1000 FT. THIS EVENT WILL WIND DOWN
AFTER 1600 UTC AS TEMPERATURES WARM ABOVE FREEZING AND LIFT BEGINS
TO WANE. WINDS WILL BE NORTHERLY 6-10KTS THROUGH 16/12...THEN
BECOMING WESTERLY. 75
&&
.PREV DISCUSSION... /ISSUED 448 AM CST TUE JAN 15 2013/
SHORT TERM WINTER WEATHER CONCERNS...
ONCE AGAIN WE HAVE A THREAT FOR WINTRY PRECIPITATION TO DEVELOP
OVER PORTIONS OF NORTH AND CENTRAL TX EARLY THIS MORNING. THE LONG
WAVE TROUGH OVER THE WESTERN CONUS HAS BECOME POSITIVELY TILTED
ALREADY THIS MORNING AND ITS AXIS NOW ORIENTED FROM NORTHERN
MINNESOTA SOUTHWEST TO THE SOUTHERN NEW MEXICO AND ARIZONA BORDER.
THE TROUGH WAS SHOWING SIGNS OF MOVING EAST ALREADY EARLY THIS
MORNING. THIS EASTWARD MOVEMENT...COMBINED WITH A COMPACT
SHORTWAVE TROUGH EMBEDDED IN THE SOUTHWEST FLOW ALOFT OVER THE
SOUTHERN HIGH PLAINS IS LIKELY PROVIDING THE LARGE SCALE FORCING
FOR ASCENT EVIDENT ON WATER VAPOR IMAGERY OVER NORTH TX AT THIS
TIME. EVIDENCE OF LARGE SCALE FORCING FOR ASCENT WAS SHOWING UP IN
IR SATELLITE IMAGERY AND VWP PROFILES EARLY THIS MORNING AS WELL.
IR SATELLITE IMAGERY INDICATES COOLING CLOUD TOPS OVER MUCH OF
NORTH AND CENTRAL TX WHILE REGIONAL RADAR VWP SHOWS LOW LEVEL FLOW
VEERING STRONGLY WITH HEIGHT...A SIGN OF WARM AIR ADVECTION AND
ISENTROPIC LIFT. ALL OF THIS IS EVIDENCE THAT WE WILL LIKELY SEE
RADAR RETURNS BLOSSOM AROUND NORTH AND CENTRAL TX THIS MORNING AS
PERSISTENT ASCENT EVENTUALLY RESULTS IN SCATTERED PRECIPITATION
DEVELOP OVER THE REGION.
CONFIDENCE IS FAIRLY HIGH THAT PRECIPITATION WILL DEVELOP OVER
MOST AREAS ALONG AND SOUTHEAST OF A BONHAM TO FORT WORTH TO
LAMPASAS LINE EARLY THIS MORNING. AS A RESULT WENT AHEAD AND
BUMPED UP POPS INTO THE 30 TO 50 PERCENT RANGE FOR THESE LOCATIONS
THROUGH THE MORNING HOURS. CONFIDENCE WAVERS WHEN DETERMINING WHAT
FORM THIS PRECIPITATION WILL FALL AS IT DEVELOPS AND MOVES
NORTHEAST OVER THESE LOCATIONS. THERE ARE SEVERAL FACTORS TO
CONSIDER...AND ILL DETAIL SOME OF THOSE BELOW.
THE EASIEST THING TO NOTICE IS THAT SURFACE TEMPERATURES ARE A
GOOD 5 DEGREES WARMER THAN EXPECTED TO START OFF THE FORECAST
TODAY. THIS IS ONE GOOD CONSEQUENCE OF THE MODELS UNDERESTIMATING
THE STRENGTH OF LARGE SCALE FORCING FOR ASCENT OVER THE
REGION...CLOUDS BUILT IN EARLIER THAN EXPECTED WHICH PREVENTED
TEMPERATURES FROM FALLING BELOW FREEZING SOUTH OF INTERSTATE
20...AT LEAST AS OF 4 AM CST. THIS AT LEAST ALLEVIATES CONCERNS
FOR FREEZING RAIN OVER THE WACO/KILLEEN/TEMPLE AREAS EARLY THIS
MORNING.
FURTHER NORTH...PRECIPITATION IS EXPECTED TO DEVELOP AROUND OR
AFTER 5 AM CST NEAR THE DFW METROPLEX...WHILE 4 AM SURFACE
OBSERVATIONS INDICATED THAT THE WET BULB ZERO LINE WAS LOCATED AS
FAR SOUTH AS CLEBURNE AND WAXAHACHIE. 05Z AMDAR AIRCRAFT SOUNDINGS
INDICATED THAT THE THERMAL PROFILE OVER THE METROPLEX WAS MOSTLY
SUPPORTIVE OF SNOW...WITH A SURFACE TO 700 MB ISOTHERMAL LAYER
HUGGING THE 0 DEG C LINE. THIS OBSERVATION WAS TAKEN FROM AIRCRAFT
BEFORE THE STRONGER LARGE SCALE FORCING FOR ASCENT BUILT OVER THE
AREA...WHICH SHOULD ONLY RESULT IN COOLING ALOFT. AS A RESULT WENT
AHEAD AND ISSUED A WINTER WEATHER ADVISORY FOR THE DFW METROPLEX
AND LOCATIONS TO THE EAST AND NORTHEAST AS THESE LOCATIONS ARE THE
MOST LIKELY TO SEE LIGHT ACCUMULATIONS OF SNOW WITH SOME SLEET
MIXED IN THIS MORNING.
IN TERMS OF AMOUNTS...SNOW OR SLEET AMOUNTS ARE EXPECTED TO VARY
WITHIN THE ADVISORY FROM TRACE AMOUNTS UP TO ONE HALF INCH. THE
VARIATION IS BECAUSE MOST PRECIPITATION IS EXPECTED TO DEVELOP IN
A BANDED FORM WHICH MEANS LOCATIONS WITHIN SNOW BANDS WILL LIKELY
SEE WINTRY PRECIPITATION ACCUMULATE...WHILE THOSE AREAS NOT
INCLUDED IN BANDS MAY SEE LIGHT PRECIPITATION...OR NOTHING AT ALL.
BANDED PRECIPITATION IS FAVORED BECAUSE THE GFS AND NAM BOTH
INDICATE THAT PRECIPITATION IN THE WINTER WEATHER ADVISORY AREA
WILL BE ENHANCED BY FRONTOGENETIC FORCING...MAXIMIZED IN THE H800
TO H700 LAYER. ABOVE 700 MB...BOTH MODELS ALSO INDICATE A
RELATIVELY DEEP LAYER OF NEGATIVE SATURATED EPV (EQUIVALENT
GEOSTROPHIC POTENTIAL VORTICITY) WHICH INDICATES THAT VERTICAL
MOTIONS INITIATED AT THE BOTTOM OF THIS LAYER WILL RESULT IN A
RELEASE OF EITHER CONVECTIVE OR SLANTWISE INSTABILITY. THERE IS A
SHALLOW LAYER OF THETA-E TEMPERATURE DECREASE WITH HEIGHT WITHIN
THIS LAYER...SO A MIX OF CELLULAR AND BANDED PRECIPITATION IS
LIKELY TO OCCUR. EITHER WAY...THIS TYPE OF FORCING AND INSTABILITY
COMBINATION OFTEN FAVORS LARGE GRADIENTS OF WINTRY ACCUMULATION
AND THAT IS WHAT IS EXPECTED ACROSS NORTH TX THIS MORNING.
IN TERMS OF IMPACTS...WENT AHEAD WITH THE WINTER WEATHER ADVISORY
WITHOUT 100 PERCENT CONFIDENCE THAT LOCATIONS IN THE ADVISORY WILL
ALL SEE ACCUMULATING WINTRY PRECIPITATION. THESE ARE SIMPLY THE
AREAS THAT HAVE THE BEST DIAGNOSED COMBINATION OF FORCING AND
MESOSCALE ENHANCEMENTS THIS MORNING. THE ADVISORY WAS ISSUED
BEFORE RADAR RETURNS HAD DEVELOPED OVER THE ADVISORY AREA TO GIVE
EVERYONE WAKING UP EARLY THIS MORNING A HEADS UP ON THE THREAT OF
WINTRY WEATHER IMPACTING THE MORNING COMMUTE. ASSUMING BANDED
WINTRY PRECIPITATION DEVELOPS OVER THE METROPLEX AROUND 5 AM AS
EXPECTED...THIS IS EXPECTED TO HAVE A VERY NEGATIVE IMPACT ON THE
MORNING RUSH HOUR...POSSIBLY CAUSING SIGNIFICANT DELAYS FOR THE
MORNING COMMUTE. BECAUSE TEMPERATURES ARE HOVERING RIGHT AROUND
FREEZING...MOST ROAD SURFACES IN CONTACT WITH THE GROUND SHOULD
SEE MOST SNOW AND SLEET MELT UPON LANDING AS GROUND TEMPERATURES
REMAIN WELL ABOVE FREEZING. BRIDGES AND OVERPASSES HOWEVER ARE
LIKELY TO RETAIN WINTRY ACCUMULATIONS THIS MORNING...RESULTING IN
ICY CONDITIONS ON ELEVATED ROADWAYS...ESPECIALLY AS TRAFFIC DRIVES
OVER IT...COMPACTING ANY ACCUMULATIONS INTO ICE. WINTRY
PRECIPITATION IS EXPECTED TO MOVE NORTHEAST OR DISSIPATE FOR THE
MOST PART AFTER 9 AM CST. LEFT THE ADVISORY GOING THROUGH 10 AM AS
IT MAY TAKE AN HOUR OR SO AFTER WINTRY PRECIPITATION CEASES BEFORE
ROAD CONDITIONS IMPROVE.
REMAINDER OF THE FORECAST...ALL 15/00Z GUIDANCE INDICATES THAT THE
LARGE UPPER TROUGH TO OUR WEST WILL REMAIN POSITIVELY TILTED AS IT
MOVES OVER THE SOUTH PLAINS OVERNIGHT INTO WEDNESDAY MORNING. THIS
WILL RESULT IN SOME LIGHT RAINFALL WEDNESDAY MORNING SOUTHEAST OF A
CANTON TO WACO LINE ASSUMING THE MODELS ARE RESOLVING THIS TROUGHS
EVOLUTION WELL. WITH NO GUIDANCE OFFERING UP THE CLOSED LOW
SOLUTION ANYMORE...DO NOT HAVE ANYTHING IN THE FORECAST TO HANDLE
THIS NOW UNLIKELY ALTERNATIVE SCENARIO. IT SEEMS THAT AFTER THIS
MORNINGS COMPACT SHORTWAVE TROUGH MOVES NORTHEAST...THE LOWER
TROPOSPHERE WILL BECOME DOMINATED ONCE AGAIN BY COLD AIR ADVECTION
WHICH WOULD SERVE TO KEEP THE TROUGH POSITIVELY TILTED AS IT MOVED
OVER THE CWA. ONE IMPORTANT CAVEAT HERE...WILL HAVE TO SEE HOW
LONG AND INTENSE PRECIPITATION ACTUALLY IS ACROSS NORTH...CENTRAL
AND EAST TX TODAY. IF PRECIPITATION HANGS AROUND LONGER THAN
EXPECTED OR IS JUST MORE INTENSE THAN EXPECTED...PRECIPITATION
WILL RELEASE MORE LATENT HEAT INTO THE MIDDLE TROPOSPHERE THAN THE
MODELS WERE PLANNING ON. WITH NO GUIDANCE FAVORING THE CUT-OFF LOW
SOLUTION ANYMORE...ITS HARD TO IMAGINE WE GET ENOUGH LATENT HEAT
RELEASE TO RAISE THICKNESSES ENOUGH DOWNSTREAM TO HAVE AN IMPACT
ON THE TILT OF THIS TROUGH. HOWEVER IT IS THE ONE THING TO WATCH
FOR DURING THE DAY TODAY...IF DEVELOPING PRECIPITATION RESULTS IN
RIDGING OVER EAST TX...THE UPPER CLOUD COULD MAKE AN ATTEMPT AT
BECOMING NEUTRALLY TILTED OR CUTTING OFF AS IT MOVES TOWARDS THE
CWA OVER THE NEXT 24 HRS. WHILE UNLIKELY...WE WILL NEED TO WATCH
FOR THIS JUST IN CASE THE MODELS HAVE MISSED SOMETHING IMPORTANT
HERE.
THURSDAY AND BEYOND...ONCE THIS UPPER TROUGH MOVES EAST OF THE
SOUTH PLAINS...WE WILL MAINTAIN A DRY FORECAST THROUGH EARLY NEXT
WEEK. TEMPERATURES WILL SLOWLY MODERATE BEHIND THE TROUGH...WITH
HIGHS MAKING A RUN AT 60 DEGREES BY SATURDAY AFTERNOON. WE ARE
STILL LOOKING AT A STRONG COLD FRONT TO KICK OFF THE UPCOMING WORK
WEEK. THE ECMWF IS BACK TO INDICATING A FAIRLY ROBUST PUNCH OF DRY
ARCTIC AIR WHILE THE GFS CONTINUES TO ADVERTISE A COOL BUT
MODIFIED AIRMASS SINKING SOUTH THROUGH THE PLAINS. WENT AHEAD WITH
THE COLDER END OF THE SPECTRUM OF AVAILABLE GUIDANCE BUT MAY HAVE
TO GO EVEN LOWER WITH TEMPS IF THE ECMWF VERIFIES.
CAVANAUGH
&&
.PRELIMINARY POINT TEMPS/POPS...
DALLAS-FT. WORTH, TX 36 27 50 33 53 / 60 10 10 10 0
WACO, TX 35 27 51 30 55 / 50 10 20 10 0
PARIS, TX 36 25 46 29 51 / 60 10 10 10 0
DENTON, TX 37 26 49 29 51 / 60 10 10 10 0
MCKINNEY, TX 36 26 47 29 51 / 60 10 10 10 0
DALLAS, TX 35 28 51 34 53 / 60 10 10 10 0
TERRELL, TX 34 26 48 30 53 / 60 10 10 10 0
CORSICANA, TX 34 28 49 31 54 / 50 10 20 10 0
TEMPLE, TX 35 28 50 30 54 / 40 10 20 10 0
MINERAL WELLS, TX 38 24 52 28 55 / 30 10 10 10 0
&&
.FWD WATCHES/WARNINGS/ADVISORIES...
WINTER WEATHER ADVISORY UNTIL NOON CST TODAY FOR TXZ092>095-
102>107-117>123-130>135-144>146-148.
&&
$$
85/85
AREA FORECAST DISCUSSION
NWS FORT WORTH TX
1146 PM CST MON JAN 14 2013
.AVIATION...
MODELS CONTINUE TO SHOW ONLY VERY LOW CHANCES OF WINTER PRECIP IN
METROPLEX WITH NO ACCUMULATIONS. HAVE NOT ADDED WINTRY PRECIP TO
TAFS.
HAVE ADDED TEMPO -PL TO WACO TAF NEAR SUNRISE AS GFS/NAM MODELS
NOW SHOW A SATURATED AREA BELOW 700MB COMBINED WITH LIFT THROUGH
THE LAYER. 04Z RAP KEEPS MOISTURE MUCH MORE SHALLOW...AS DID THE
18Z TTU WRF. GFS/NAM 290K ISENTROPIC SURFACE SHOWS THE LIFT
BEST. 84
&&
.UPDATE...
A VERY DEEP TROUGH CONTINUES TO ROTATE THROUGH NEW MEXICO THIS
EVENING. INCREASING LARGE SCALE LIFT ALONG WITH SOME WEAK UPSLOPE
FLOW CONTINUES TO PRODUCE AREAS OF LIGHT SNOW ACROSS EASTERN NEW
MEXICO AND THE WESTERN TEXAS PANHANDLE. THE LATEST COMPUTER
GUIDANCE INCLUDING HIGH RES SOLUTIONS ALL HOLD PRECIP OFF ACROSS
NORTH TEXAS UNTIL WELL AFTER 06Z. ALL SOLUTIONS KEEP PRECIP
AMOUNTS LIGHT. AT THIS TIME WE SEE NO REASON TO DISAGREE SINCE
MOISTURE WILL BE LIMITED OVER MOST OF THE AREA. STILL FEEL THAT
LIGHT FREEZING RAIN AND SLEET WILL BE POSSIBLE...ESPECIALLY ACROSS
THE SOUTH/SOUTHEAST ZONES. WILL HOLD OFF ON ANY TYPE OF ADVISORY
AT THIS TIME.
WILL ONLY MAKE SOME MINOR CLOUD COVER AND TEMPERATURE CHANGES WITH
THIS UPDATE.
79
&&
.PREV DISCUSSION... /ISSUED 303 PM CST MON JAN 14 2013/
THE FORECAST OVER THE NEXT SEVERAL DAYS REMAINS DIFFICULT AS
THERE IS THE POSSIBILITY OF THE OCCURRENCE OF WINTER WEATHER THREE
TIMES THROUGH THURSDAY MORNING. LATEST WATER VAPOR IMAGERY SHOWS A
DEEP TROUGH OVER THE WESTERN CONUS...WITH SOUTHWESTERLY FLOW
SETUP ACROSS TEXAS AND INTO THE OHIO VALLEY AHEAD OF THE TROUGH. A
DISTURBANCE CAN CURRENTLY BE SEEN IN EASTERN MISSOURI AND IT WAS
THIS DISTURBANCE WHICH BROUGHT SLEET AND FREEZING RAIN TO PORTIONS
OF NORTH TEXAS THIS MORNING.
ANOTHER ROUND OF WINTER WEATHER IS AGAIN POSSIBLE TONIGHT. AN IMPULSE
OF ENERGY CAN BE SEEN ROUNDING THE BASE OF THE TROUGH AND EXPECT
THIS FEATURE TO MOVE THROUGH THE FORECAST AREA AROUND DAYBREAK.
MODELS ARE IN VERY GOOD AGREEMENT OF DEEP LIFT ON ISENTROPIC
SURFACES...IN THE MID-LEVELS OF THE ATMOSPHERE. THE GFS/ECMWF
INDICATE SHARP MOISTURE ADVECTION THAT IS EVIDENT ON 700 MB
THETA-E PLOTS BY 12Z. THIS WARM AIR/MOISTURE ADVECTION WILL PROVIDE
SUFFICIENT LIFT FOR PRECIPITATION...AS LONG AS MOISTURE THROUGHOUT
THE ATMOSPHERIC COLUMN IS ADEQUATE. THE GFS/ECMWF/CANADIAN ALL
HAVE PROFILES THAT SUPPORT LIGHT PRECIPITATION WHILE THE NAM...IS
DRIER IN THE LOWER ATMOSPHERE AND WOULD ONLY SUPPORT TRACE AMOUNTS
OF PRECIP. THE NEXT VARIABLE TO DETERMINE WINTER PRECIP CHANCES
WILL BE THE SURFACE TEMPERATURES. IT DOES APPEAR THAT THE TEMPS BY
MORNING SHOULD BE AT OR BELOW FREEZING FOR THE ENTIRE CWA...AND A
SLEET/FREEZING RAIN MIXTURE WOULD BE THE PREDOMINANT PRECIP TYPE.
IF TEMPS ARE A BIT WARMER ACROSS THE EXTREME SOUTHERN COUNTIES
THEN RAIN/SLEET WOULD OCCUR. HIGHEST CHANCES FOR PRECIP/ACCUMULATIONS
WILL ONCE AGAIN BE ACROSS THE SOUTHERN ZONES...WHERE THE BEST
MOISTURE IS LOCATED. CONFIDENCE IS INCREASING THAT FROZEN PRECIP
WILL IMPACT SOME LOCATIONS ACROSS THE SOUTHEASTERN ZONES...BUT
CONFIDENCE OF WIDESPREAD IMPACTS ARE NOT HIGH AND WILL NOT ISSUE A
WINTER WEATHER ADVISORY AT THIS TIME. WILL HANDLE THE EXPECTED
IMPACTS WITH A SPECIAL WEATHER STATEMENT AND IF COVERAGE OF WINTER
PRECIP APPEARS TO BE HIGHER...FUTURE SHIFTS MAY UPGRADE TO AN
ADVISORY. MODELS...SHOW LITTLE MOISTURE FURTHER NORTH INTO THE
METROPLEX...BUT LIFT COULD BE ENOUGH TO TAP INTO WHAT LITTLE
MOISTURE IS AVAILABLE AND PRODUCE SNOW GRAINS OR SLEET SIMILAR TO
LAST NIGHT. WILL MENTION SLEET WITH A 10 POP...BUT NO
ACCUMULATIONS ARE EXPECTED.
THE FOCUS AFTER TOMORROW MORNING WILL SHIFT TO WEDNESDAY/THURSDAY
WHEN THE UPPER TROUGH CLOSES OFF AND MOVES ACROSS NORTH TEXAS.
THERE REMAINS CONSISTENCY BETWEEN THE GFS/ECMWF/CANADIAN ON A
POSITIVELY TILTED TROUGH CLOSING OFF JUST WEST OF THE CWA AND
REMAINING IN ITS POSITIVE TILT AS IT MOVES ACROSS NORTH TEXAS.
THIS SOLUTION WOULD KEEP THE 850/700 MB FLOW FROM THE
WEST/SOUTHWEST WHICH ALLOWS FOR NO MOISTURE TO ADVECT INTO THE
AREA...AND THUS THESE SOLUTIONS FORECAST DRY WEATHER. THIS
POSITIVE TILT ALSO PROVIDES FORCING FOR THE 850/700 FRONTS TO PUSH
SOUTH OF THE FORECAST AREA BY WEDNESDAY MORNING...AND THEREFORE WE
WOULDNT HAVE A THIRD MORNING OF WINTER WEATHER ACROSS THE
SOUTHEASTERN ZONES. ONCE THE TROUGH PASSES NORTH TEXAS...IT IS
FORECASTED TO BECOME NEUTRAL AND PRECIP IS EXPECTED FOR
LA/MS/AL...BUT THE TROUGH WOULD BE WELL EAST BEFORE MOISTURE IS
ABLE TO BUILD ON THE BACKSIDE OF THE SYSTEM.
THE NAM REMAINS THE OUTLIER AND CUTS OFF THE SYSTEM A BIT SOONER
THAN THE REST OF THE GUIDANCE AND GIVES IT A NEUTRAL ORIENTATION
BEFORE IT ARRIVES INTO NORTH TEXAS. THIS WOULD ALLOW FOR MOIST
ADVECTION/WARM AIR ADVECTION AHEAD OF THE SYSTEM AND RAIN WOULD
OCCUR IN ADVANCE OF THE TROUGH WEDNESDAY AFTERNOON...WITH THE
POSSIBILITY OF ANOTHER ROUND OF WINTER WEATHER ACROSS THE EXTREME
SOUTH WEDNESDAY MORNING. MOISTURE THEN WOULD BE ABLE TO BE
TRANSPORTED ON THE BACKSIDE OF THE SYSTEM AND THEN ANOTHER ROUND
OF WINTER PRECIP IN THE FORM OF SNOW WOULD BE POSSIBLE WEDNESDAY
NIGHT. THIS SOLUTION IS NOT SUPPORTED BY OTHER GUIDANCE AND WILL
KEEP THE FORECAST MOSTLY DRY WEDNESDAY AND THURSDAY. WILL ONLY
CARRY A 20 POP WEDNESDAY AFTERNOON AND EVENING AHEAD OF THE FRONT
WHEN THE BEST LIFT OVERSPREADS THE AREA. THIS PRECIP WOULD BE IN
THE FORM OF RAIN. WE STILL HAVE 48 HOURS TO WATCH THIS SYSTEM AND
ADDITIONAL CHANGES ARE POSSIBLE.
COLD TEMPERATURES ARE EXPECTED TO LAST FOR MOST OF THE PERIOD AS
NORTH FLOW REMAINS IN PLACE. SOUTHERLY WINDS RETURN FRIDAY AND
SATURDAY AND HIGHS WILL WARM INTO THE 50S...BUT ANOTHER FRONT
COMES MONDAY AND HIGHS COULD BE BACK INTO THE 40S.
HAMPSHIRE
&&
.PRELIMINARY POINT TEMPS/POPS...
DALLAS-FT. WORTH, TX 27 42 28 50 34 / 5 10 10 10 10
WACO, TX 29 44 26 49 31 / 10 20 10 20 20
PARIS, TX 25 40 24 48 31 / 5 10 10 20 20
DENTON, TX 23 41 23 49 30 / 5 10 10 10 10
MCKINNEY, TX 23 41 24 49 31 / 5 10 10 10 10
DALLAS, TX 29 42 29 50 36 / 5 10 10 10 10
TERRELL, TX 26 41 24 51 31 / 5 10 10 20 20
CORSICANA, TX 29 40 28 49 33 / 10 20 10 20 20
TEMPLE, TX 28 41 27 48 31 / 10 20 10 20 20
MINERAL WELLS, TX 22 43 23 51 30 / 0 10 10 10 10
&&
.FWD WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
/
AREA FORECAST DISCUSSION
NWS MILWAUKEE/SULLIVAN WI
1045 PM CST MON JAN 14 2013
.UPDATE...
.AVIATION/06Z TAFS/...A HIGH PRESSURE RIDGE FROM MO TO SRN WI
WILL SLOWLY SHIFT SEWD ON TUE WITH SWLY WINDS DEVELOPING. THE
AIRMASS WILL REMAIN DRY WITH VFR CONDITIONS FOR TUE AND TUE NT.
&&
.PREV DISCUSSION... /ISSUED 331 PM CST MON JAN 14 2013/
TONIGHT AND TUESDAY...FORECAST CONFIDENCE...HIGH
AN AREA OF LOW LEVEL CLOUDS WILL LIKELY AFFECT THE NORTHWEST HALF OF
THE FORECAST AREA LATE THIS AFTERNOON AND INTO TONIGHT. HIGH LEVEL
CLOUDS ARE POSSIBLE ELSEWHERE. THE LOW LEVEL CLOUDS SHOULD MOVE ON
OR SCATTER OUT BY LATE IN THE NIGHT...WITH SOME MID LEVEL CLOUDS
LINGERING TUESDAY MORNING. SKIES SHOULD BECOME MOSTLY SUNNY BY THE
AFTERNOON.
LOWS A LITTLE TRICKY TONIGHT...ALL DEPENDING ON HOW LONG CLOUDS
STICK AROUND...AS WINDS WILL BE LIGHT. GENERALLY WENT WITH A
CONSENSUS FOR LOWS...AS THE ECMWF/GFS/NAM SOLUTIONS NOT TOO FAR
APART. COULD SEE TEMPS GET A FEW DEGREES COLDER THAN EXPECTED IF
SKIES CLEAR UP SOONER THAN EXPECTED...RESULTING IN A LONGER PERIOD
OF GOOD RADIATIONAL COOLING CONDITIONS. HIGH TEMPS SHOULD BE BACK
AROUND NORMAL TUESDAY...MAYBE EVEN A DEGREE OR TWO ABOVE AVERAGE
VALUES FOR MID JANUARY.
SHORT TERM...TUESDAY NIGHT THROUGH THURSDAY.
MID TO UPPER LEVEL TROUGH AXES SHIFT EAST...WITH SHORT WAVE DROPPING
SE TUESDAY NIGHT/WEDNESDAY IN LEFT EXIT REGION OF UPPER LEVEL JET
MAX TOPPING WESTERN RIDGE AND NOSING INTO THE UPPER MIDWEST. AFTER
THIS WAVE CLEARS THE REGION...MODELS VARY IN PLACEMENT OF CHANNELED
VORTICITY IN CONFLUENT FLOW UNDER HUDSON BAY POLAR VORTEX FOR THE
REST OF THE SHORT TERM BUT GENERALLY KEEP IT TIED TO THE UPPER
JET...STAYING NORTH OF FORECAST AREA.
TUESDAY NIGHT AND WEDNESDAY...FORECAST CONFIDENCE MEDIUM.
TEMPERATURES FALL TUESDAY EVENING WITH READINGS HOLDING STEADY OR
RISING AFTER LOWS ARE REACHED AROUND MIDNIGHT AS SOUTHWEST WINDS
INCREASE AHEAD OF APPROACHING SHORT WAVE. LOCATION OF BEST FORCING
WITH WAVE VARIES WITH MODEL TRACK AND STRENGTH DIFFERENCES.
CONSENSUS KEEPS THE BETTER CHANCES FOR ACCUMULATING SNOW ACROSS NRN
WI...WHICH LEADS TO CHANCE OF LIGHT SNOW IN THE FAR NORTH AND SLIGHT
CHANCE ELSEWHERE MAINLY WEDNESDAY MORNING. BRIEF PERIOD OF LIFT AND
DEEP MOISTURE INTO THE DENDRITE GROWTH ZONE...ALONG WITH
PRECIPITABLE WATER ONLY REACHING 1/3 INCH SO DURING MOST FAVORABLE
TIME FOR PRECIPITATION...MEANS MINIMAL ACCUMULATIONS OF A FEW TENTHS
OF AN INCH AT MOST.
GUSTY WINDS ON WEDNESDAY WITH TIGHT GRADIENT AROUND SOUTHERN CANADA
LOW. AGAIN A CONSENSUS BLEND TEMPERING THE STRONGER NAM WINDS BUT
THIS STILL BRINGS 15 TO 25 MPH SOUTHWEST WINDS...SHIFTING WEST
BEHIND THE SURFACE TROUGH/COLD FRONT...WITH A FEW GUSTS TO 30 MPH.
THE GUSTY SOUTHWEST WINDS PUSH A THERMAL RIDGE AHEAD OF SURFACE
TROUGH OVER THE CWA MIDDAY...WITH BLENDED TEMPERATURES BRINGING
HIGHS IN THE LOWER TO MIDDLE 30S...THOUGH TEMPS COULD BE LOWER IF
FASTER MOVEMENT OF COLD FRONT REFLECTED IN THE GFS AND GEMNH OCCURS.
WEDNESDAY NIGHT AND THURSDAY...FORECAST CONFIDENCE MEDIUM TO HIGH.
WEST-NORTHWEST FLOW BEHIND LOW SHUNTS COLDEST AIR OFF TO THE
NORTHEAST OF THE REGION OVER SOUTHEAST CANADA...BUT ENOUGH COLD AIR
ADVECTION TO BRING SINGLE DIGIT LOWS TO THE NORTH WEDNESDAY
NIGHT...WITH MID-TEENS IN THE SOUTH. HIGH PRESSURE BRINGS QUIET
WEATHER WITH NEUTRAL TEMPERATURE ADVECTION BRINGING HIGHS IN THE
TEENS NORTH TO LOWER 20S SOUTH.
LONG TERM...THURSDAY NIGHT THROUGH MONDAY. FORECAST CONFIDENCE
LOW TO MEDIUM.
WEAK WAVES PASSING BY TO THE NORTH IN THE NEAR ZONAL FLOW LIFT
850/925MB TEMPERATURES ENOUGH TO WARM HIGHS INTO THE LOWER TO MIDDLE
30S FOR FRIDAY AND SATURDAY. FAR NORTH MAY BE BRUSHED BY LIGHT SNOW
WITH THE WARM ADVECTION PUSH THURSDAY NIGHT...AND ONLY A LITTLE
BETTER CHANCE SATURDAY/SATURDAY NIGHT WITH STRONGER WAVE CROSSING
NORTHERN WISCONSIN. COLD ADVECTION AROUND ARCTIC HIGH SETTLING INTO
THE PLAINS BEHIND THIS LAST WAVE BRINGS HIGHS IN THE TEENS
SUNDAY...WITH SINGLE DIGIT LOWS SUNDAY NIGHT. BLENDED HIGHS ON LY IN
THE SINGLE DIGITS TO LOWER TEENS MONDAY...THEN FALLING TO BELOW
ZERO AWAY FROM LAKE MICHIGAN MONDAY NIGHT. IF COLDER GFS PANS
OUT...READINGS COULD GET EVEN COLDER.
AVIATION/00Z TAFS/...
STILL WATCHING AN AREA OF MVFR CIGS UPSTREAM. LATEST RAP AND NAM RH
FIELDS INDICATE THIS MAY HOLD TOGETHER AND MOVE INTO THE NORTHWEST
HALF OF THE FORECAST AREA MID TO LATE THIS AFTERNOON. BEST CHANCE
FOR THESE LOWER CIGS APPEARS TO BE ROUGHLY ALONG AND NORTHWEST OF A
MINERAL POINT TO SHEBOYGAN LINE...AS THE HIGH RH IN THE MODELS NEVER
QUITE MAKES IT TO THE SOUTHEAST. WILL CONTINUE TO KEEP AN EYE ON
SATELLITE TRENDS AND MODIFY TAFS AS NEEDED.
ANY LOWER CIGS SHOULD SCATTER OUT OR MOVE OUT BY MORNING...WITH VFR
CONDITIONS THEN EXPECTED THROUGH THE DAY TUESDAY.
MARINE...
SOUTHWEST WINDS WILL INCREASE TUESDAY NIGHT AHEAD OF AN APPROACHING
TROUGH OF LOW PRESSURE. WIND GUSTS ARE EXPECTED TO PEAK IN THE 30-35
KT RANGE LATE TUESDAY NIGHT THROUGH WEDNESDAY MORNING. MODELS
CURRENTLY INDICATING GUSTS RIGHT ON THE VERGE OF GALE
FORCE...ESPECIALLY TOWARD OPEN WATERS...SO WILL GO WITH A GALE WATCH
FOR THIS PERIOD OF HIGHER GUSTS. WILL LIKELY SEE GUSTS TO SMALL
CRAFT LEVELS EARLIER IN THE NIGHT AS THINGS RAMP UP...AND INTO
WEDNESDAY AFTERNOON AS WINDS EASE.
THE HIGHEST WAVES WILL BE ACROSS THE NORTH AND TOWARD OPEN WATERS
DUE TO THE EXPECTED SOUTHWEST FLOW. NOT EXPECTING WAVES WILL GET
PARTICULARLY HIGH GIVEN THE OFFSHORE COMPONENT TO THE WINDS.
&&
.MKX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
LM...GALE WATCH FROM LATE TUESDAY NIGHT THROUGH WEDNESDAY MORNING FOR
LMZ643>646.
&&
$$
UPDATE...GEHRING
TONIGHT/TUESDAY AND AVIATION/MARINE...DDV
TUESDAY NIGHT THROUGH MONDAY...REM
AREA FORECAST DISCUSSION
NWS TWIN CITIES/CHANHASSEN MN
1050 PM CST WED JAN 16 2013
.UPDATE...FOR 06Z AVIATION DISCUSSION BELOW
&&
.DISCUSSION.../ISSUED 358 PM CST WED JAN 16 2013/
TONIGHT AND THURSDAY...LOW PRES TRIPLE POINT CENTER TRAVERSING ESE
THRU WRN WI WITH THE CDFNT SNAKING EWD THRU KMSP TWD KABR...AND
THIS CDFNT WILL CONTINUE TO PRES SE THRU THE REST OF THE EVE.
BATCH OF -SN THAT PUSHED THROUGH MAINLY WRN AND SRN PORTIONS OF
THE TWIN CITIES REGION HAS SHIFTED OFF TO THE SE SO AM NOT
EXPECTING MUCH MORE OF ANY ACCUMULATING OR VISIBILITY-HAMPERING
SNOWFALL. THE SNOW WILL COME TO AN END OVER THE MPX CWFA BY LATE
EVENING THEN COLDER HIGH PRES WILL SLIDE SE LATE TNGT THRU TMRW.
SKIES WILL PARTIALLY CLEAR OUT...BUT THE MAIN IMPACT WILL BE
STRONGER CAA. AFTER HIGHS THAT RANGED THRU THE 30S THIS AFTN...THE
POST-FRONTAL CAA WILL FORCE LOWS THAT WILL SPAN FROM 10 DEGREES
ABOVE ZERO TO 10 DEGREES BELOW ZERO TONIGHT. THIS WILL THEN BE
FOLLOWED BY HIGHS FROM AROUND 10 TO THE LOWER 20S FOR THU.
THURSDAY NIGHT THROUGH SATURDAY...THE AREA OF HIGH PRES WILL ONLY
BE SHORT-LIVED AS IT SHIFTS OFF TO THE SE THU NIGHT INTO FRI WHILE
A WMFNT NUDGES IN FROM THE W. THIS WILL RESULT IN NOT ONLY A
WARMING TREND FRI INTO FRI NIGHT BUT ALSO THE POTENTIAL FOR SOME
SNOW SHOWERS OR LIGHT SNOW FOR MAINLY NRN AND ERN PORTIONS OF THE
MPX CWFA THU NIGHT THRU SAT AS THE FNT WILL SLOWLY LIFT OUT AND
GIVE WAY TO SEVERAL UPPER LEVEL DISTURBANCES PLUS A TRAILING CDFNT
FOR SAT. POPS ARE NO HIGHER THAN CHC RANGE AND ACCUMULATIONS...IF
ANY...WILL BE MINOR. AS FOR TEMPS...THE SIGNIFICANT WARM-UP FOR
FRI WILL BRING HIGHS AROUND 40 NEAR THE IA BORDER WITH 30S
ELSEWHERE THROUGHOUT THE CWFA. HOWEVER...THE MAIN CDFNT WHICH WILL
BE THE FOCUS FOR A SIGNIFICANT ARCTIC CHILL WILL PUSH THROUGH LATE
SAT SO ALTHOUGH HIGHS WILL DROP OFF ONLY TO THE LOW 20S TO LOW
30S... CAA WILL ABSOLUTELY COMMENCE BY LATE DAY SAT. WINDS WILL
ALSO BE ON THE INCRS DURG THE DAY SAT WITH A TIGHT POST-FRONTAL
PRES GRADIENT AND STRONG JETTING. WIND CHILL VALUES BY LATE DAY
SATURDAY WILL BE IN THE SINGLE DIGITS IN FAR SRN AND ERN
PORTIONS... WHILE NRN AND WRN PORTIONS WILL DROP TO AS LOW AS 20
DEGREES BELOW ZERO.
SATURDAY NIGHT THROUGH TUESDAY...THE ARCTIC BLAST WILL COMMENCE
OVER THE REGION STARTING SAT NIGHT AS A 1040-1050MB HIGH PRES
CENTER FROM NRN CANADA WILL DROP INTO THE NORTH-CENTRAL CONUS. IT
WILL SETTLE OVER THE AREA MON INTO MON NIGHT...MAKING THESE TWO
PERIODS THE COLDEST THIS REGION HAS SEEN IN SOME TIME. BREEZY
CONDITIONS WILL ALSO STILL BE PRESENT WITH THE COLD AIR...SO
COMBINING HIGHS RANGING FROM ZERO TO 10 BELOW ZERO ON MON FOLLOWED
BY LOWS MON NIGHT BETWEEN 10 AND 20 BELOW ZERO WILL MAKE FOR WIND
CHILL VALUES BETWEEN 20 AND 35 DEGREES BELOW ZERO. IT/S LOOKING
MORE AND MORE LIKELY THAT WIND CHILL ADVISORIES/WARNINGS WILL BE
NEEDED. AFTER TEMPS BOTTOM OUT MON NIGHT...THE HIGH PRES CENTER
WILL PUSH OFF TO THE E...ALLOWING A MORE SOUTHERLY FLOW. THIS
WILL ALLOW HIGHS ON TUE TO CLIMB INTO THE SINGLE DIGITS ABOVE
ZERO.
&&
.AVIATION.../06Z TAF ISSUANCE/
MAIN FORECAST CONCERN THIS TAF PERIOD IS THE POTENTIAL FOR MVFR
CIGS TO MOVE INTO THE AREA FROM THE NORTHWEST OVERNIGHT AND
THURSDAY MORNING. 11-3.9 MICRON SATELLITE IMAGERY SHOWS A BLOB OF
LLVL MOISTURE OVER NORTH DAKOTA ALONG THE WESTERN PERIPHERY OF THE
SURFACE RIDGE. BOTH THE HRRR /CLOUDBASE/ AND RAP /925-850MB MOISTURE/ PROGS
SHOW THIS AREA OF MOISTURE BETWEEN 2000 AND 4000 FT ADVECTING INTO
THE MN BETWEEN 08Z AND 12Z...AND WI ON THURSDAY MORNING. WILL
RETAIN A SCT-BKN MVFR LEVEL DECK IN THE TAF ACCORDINGLY. THE 925MB
LAYER IS PROGGED TO DRY OUT THURSDAY AFTERNOON /MN/ AND EARLY EVE
/WI/...BUT QUICKLY BE REPLACED BY A WEST TO EAST SURGE OF
850-700MB MOISTURE BETWEEN 03Z AND 12Z FRIDAY. WILL INTRODUCE SNOW
INTO KAXN AROUND 03Z FRIDAY...BUT ONSET FOR THE REMAINDER OF THE
SITES WILL MOST LIKELY BE BEYOND THIS TAF PERIOD. NORTHWEST WINDS
AT 5 TO 10 KTS WILL PREVAIL THROUGH THE PERIOD.
KMSP...SCT MVFR LEVEL CLOUDS /2000 FT/ WILL BE POSSIBLE AFTER 12Z
THURSDAY...ALONG WITH A BKN VFR DECK /3500 FT/. THE 2KFT DECK
COULD BRIEFLY GO BROKEN ON THURSDAY MORNING...BUT CONFIDENCE IS
NOT HIGH ON THAT. CLEARING ENSUES IN THE AFTERNOON...WITH ANOTHER
ROUND OF CLOUDS /LOW-END VFR CIGS/ ARRIVING AFTER 06Z FRIDAY.
/OUTLOOK FOR KMSP/
FRI...VFR. CHC OF -SN AND MVFR VIS/CIG IN MORNING. WIND SW 5-15
KTS.
SAT...MVFR CIGS LIKELY. AFTERNOON -SN POSSIBLE. W WIND 5 KTS BECOMING NW
15-20 KTS WITH GUSTS TO 30 KTS.
SUN...CHANCE OF -SN WITH MVFR OR LOWER CIG/VIS. WINDS W 5-10 KTS
BECOMING NW 15-20 KTS LATE.
&&
.MPX WATCHES/WARNINGS/ADVISORIES...
MN...NONE.
WI...NONE.
&&
$$
JPC/LS
AREA FORECAST DISCUSSION...UPDATED
NWS BILLINGS MT
906 PM MST WED JAN 16 2013
.SHORT TERM...VALID FOR THU AND FRI...
A WEAK COLD FRONT WAS APPROACHING THE FORECAST AREA FROM NE MT/W
N DAKOTA THIS EVENING. MODELS INDICATED SOME WARM ADVECTION
INCREASING OVER THIS BOUNDARY LATER TONIGHT. MOISTURE WAS ALREADY
IN PLACE OVER SE MT PER SATELLITE IMAGERY AND SURFACE
OBSERVATIONS. RAP AND WRF SOUNDINGS SUPPORTED FLURRIES AFTER 06Z
AROUND KBHK. RADAR AND OBSERVATIONS WERE DRY THIS EVENING SO HAVE
REMOVED THE FLURRIES THROUGH 06Z...BUT KEPT THEM GOING OVERNIGHT.
TEMPERATURES WERE IN THE UPPER 20S AND 30S ACROSS THE AREA AT
03Z. MIN TEMPERATURES LOOKED REASONABLE FROM KBIL TO KSHR W...BUT
SEEMED A BIT LOW OVER THE EASTERN ZONES. EVEN THOUGH COLD FRONT
MOVES INTO THE E LATER TONIGHT...AIRMASS WILL NOT BE MUCH COLDER
THAN IT IS CURRENTLY...AND CLOUD COVER WILL LIMIT TEMPERATURE
FALLS. THUS HAVE RAISED THE MINS E OF KBIL.
A TIGHT SURFACE PRESSURE GRADIENT WAS OVER THE AREA W OF KBIL THIS
EVENING. WINDS OVER KLVM AND BIG TIMBER WERE IN THE 20S TO 30S MPH
RANGE. GRADIENT WAS NOT EXPECTED TO TIGHTEN FURTHER OVERNIGHT...SO
WILL NOT NEED A WIND ADVISORY. MODELS DID SHOW THE GRADIENT
STRENGTHENING THU NIGHT...SO WIND HIGHLIGHTS WILL LIKELY BE
NEEDED FOR THIS PERIOD THROUGH AT LEAST FRI. ARTHUR
.LONG TERM...VALID FOR SAT...SUN...MON...TUE...WED...
EXTENDED MODELS REMAIN IN GOOD AGREEMENT THROUGH NEXT
TUESDAY...WITH MAJOR DIFFERENCES APPEARING IN HOW THEY HANDLE A
PACIFIC STORM SYSTEM THAT LOOKS TO IMPACT THE REGION BEGINNING
LATE WEDNESDAY. NORTHWEST FLOW ALOFT WILL CONTINUE OVER THE
FORECAST AREA SATURDAY INTO MONDAY AS MODELS STILL SHOW A DEEP
UPPER LOW SITUATED OVER THE HUDSON BAY AREA AND UPPER LEVEL
RIDGING OVER THE PACIFIC COAST.
MODELS CONTINUE TO SHOW AN ARCTIC FRONT BACKDOORING INTO THE FAR
EASTERN ZONES LATE IN THE DAY SATURDAY OR SATURDAY NIGHT.
HOWEVER...CONFIDENCE IS STILL NOT HIGH AT THIS TIME AS TO THE
TIMING OF THE FRONT NOR HOW FAR WEST IT WILL TRAVEL...ALTHOUGH IT
DOES LOOK TO MAKE IT TO THE BILLINGS AREA. THE COLDEST AIR STILL
LOOKS TO REMAIN FROM ABOUT ROSEBUD COUNTY EASTWARD WITH THE VERY
BITTER COLD AIR REMAINING ACROSS NORTH DAKOTA. DID NOT MAKE ANY
SIGNIFICANT CHANGES TO THE PREVIOUS FORECAST IN REGARDS TO
TEMPERATURES FOR THE WEEKEND. AS FOR PRECIP...THERE STILL REMAINS
THE POSSIBILITY OF SOME LIGHT SNOW ALONG THE FRONT AND IN THE
ARCTIC AIRMASS ITSELF SUNDAY INTO SUNDAY NIGHT. THE ARCTIC AIR
LOOKS TO BE SHORT-LIVED AS MODELS BRING THE UPPER LEVEL RIDGE OVER
THE WEST COAST SLOWLY EASTWARD LATE MONDAY INTO EARLY WEDNESDAY.
AT THE SAME TIME...SURFACE HIGH PRESSURE SOUTHWEST OF THE REGION
COMBINES WITH SHORTWAVES IN NW FLOW TO TIGHTEN THE PRESSURE
GRADIENT ACROSS THE WEST AND ONCE AGAIN INCREASE WINDS IN THE
WESTERN FOOTHILLS. ALTHOUGH IT IS DEEP INTO THE EXTENDED...THE
MODELS HAVE HAD THIS SCENARIO PLAYING OUT FOR SEVERAL CYCLES...SO
CONFIDENCE IS INCREASING IN ANOTHER POTENTIAL HIGH WIND EVENT LATE
MONDAY INTO AT LEAST TUESDAY NIGHT. BECAUSE OF THIS...INCREASED
WIND GUSTS TO ABOUT 45 MPH FROM LIVINGSTON TO BIG TIMBER SOUTH TO
NYE ALONG THE BEARTOOTH FOOTHILLS.
IT DOES LOOK LIKE A WARM UP IS IN STORE MONDAY INTO EARLY
WEDNESDAY AS THE UPPER LEVEL RIDGING MOVES CLOSER...THE DOWNSLOPE
WINDS KICK IN AND THE ARCTIC AIR RETREATS TO THE EAST...SO ABOVE
AVERAGE TEMPS ARE LOOKING MORE LIKELY DURING THAT PERIOD. THE NEXT
PACIFIC SYSTEM MAY IMPACT THE REGION BEGINNING LATE WEDNESDAY.
TIMING AND STRENGTH OF THIS SYSTEM HAVE YET TO BE DETERMINED...SO
I MAINLY JUST TWEAKED POPS IN THE MOUNTAINS AND FOOTHILLS. STC
&&
.AVIATION...
VFR CONDITIONS CAN BE EXPECTED THROUGH THE NIGHT WITH JUST SOME
MID LEVEL CLOUDS WORKING FROM NORTHWEST TO SOUTHEAST ACROSS
SOUTHERN MONTANA AND NORTHERN WYOMING. GUSTY SOUTHWEST WINDS UP TO
30KTS WILL TAKE PLACE AT KLVM. THESE WINDS WILL INCREASE IN
STRENGTH THURSDAY AFTERNOON AND NIGHT. TWH
&&
.PRELIMINARY POINT TEMP/POPS...
THU FRI SAT SUN MON TUE WED
-----------------------------------------------------------
BIL 025/041 031/049 022/036 012/026 008/030 017/037 026/038
00/N 00/N 00/B 03/S 21/B 10/N 01/B
LVM 027/044 028/045 023/039 014/030 011/032 019/036 023/036
00/N 00/N 00/N 02/S 21/N 10/N 02/J
HDN 022/043 020/048 019/034 009/023 006/026 014/036 022/037
00/U 00/N 00/B 13/S 21/B 10/B 01/B
MLS 022/038 020/045 015/024 003/016 904/017 009/029 019/032
00/U 00/B 00/B 13/S 21/B 10/B 01/B
4BQ 021/040 020/046 015/028 006/021 002/021 010/032 018/034
00/U 00/B 00/B 13/S 21/B 10/B 01/B
BHK 020/036 023/040 013/021 001/013 909/013 004/025 016/030
10/B 00/B 00/B 13/S 11/B 11/B 01/B
SHR 018/046 021/051 016/038 011/027 006/030 016/039 021/038
00/U 00/B 00/B 12/S 21/B 10/B 01/B
&&
.BYZ WATCHES/WARNINGS/ADVISORIES...
MT...NONE.
WY...NONE.
&&
$$
WEATHER.GOV/BILLINGS
AREA FORECAST DISCUSSION
NWS BINGHAMTON NY
1250 AM EST THU JAN 17 2013
.SYNOPSIS...
THE STORM SYSTEM THAT BROUGHT THE SNOW TO THE AREA TODAY HAS
EXITED OFF OF THE EAST COAST. A COLD FRONT WILL CROSS THE AREA ON
THURSDAY BRINGING SCATTERED SNOW SHOWERS AND DROPPING TEMPERATURES
DURING THE AFTERNOON. BRIEFLY MILDER TEMPERATURES SATURDAY...WILL
BE REPLACED BY MUCH COLDER AIR EARLY NEXT WEEK.
&&
.NEAR TERM /UNTIL 6 AM THIS MORNING/...
7 PM UPDATE...
JUST MINOR TWEAKS TO HRLY T/TD GRIDS AT THIS TIME AS THEY APPEAR
TO BE RIGHT ON TARGET. SNOW HAS EXITED THE REGION TO THE EAST WITH
DRY AIR WORKING DOWN WELL INTO THE BL, LEAVING VRY LITTLE CHC FOR
LINGERING FZRA OR FZDZ. THUS POPS HV BEEN DROPPED TO ZERO UNTIL
COLD FRNT INCHES CLOSER. LIGHT SNOW IS OCCURRING ACRS SRN ONTARIO
AND CANADIAN RADARS INDICATE THIS AREA OF PCPN ABOUT READY TO
ENTER OVR LK ONTARIO. 18Z NAM AND LATEST HRRR HAS FAIRLY GOOD
HANDLE ON PCPN LOCATION AND HV USED MODEL BLENDS TO ACCNT FOR
TRENDS DRG THE OVRNGT PD.
TIMING ON FRONT BRINGS IT INTO FINGER LKS REGION BY 12Z WHICH IS
IN LINE WITH THE NAM12. SLGT CHC POPS ENTER INTO EXTRM NRN ZONES
BY 03Z AND SPREAD INTO TWIN TIERS BY 12Z. AS LK MOISTURE IS PICKED
UP, HICHC TO LKLY POPS EXPECTED ARND 12Z AS SATURATED LYR
INCREASES TO NR 800MB AND MEAN FLOW SETTLES OUT ARND 280 DEGREES.
SNOWFALL AMNTS ACRS ONEIDA CNTY THRU 12Z THURSDAY WILL BE ARND 1
INCH.
SKIES HV CLRD ACRS PORTIONS OF THE CWA AS OF 00Z AND WL DROP SOUTH
TONIGHT AS DRY AIR MVS IN BHND SYSTEM AND AHD OF APPCHG FRONTAL
BNDRY. THUS HV UPDATED SKY GRIDS TO ACCNT FOR THIS TREND AND MAY
IMPACT AMNT OF TEMP DROP WITH SNOWPACK IN PLACE ONCE AGAIN.
PREV DISCO BLO...
3 PM UPDATE...
LINGERING LIGHT PRECIP WILL MOVE OUT BY 7 PM. WITH LOW LEVEL
SATURATION NOT GOING INTO THE DENDRITE ZONE, FREEZING RAIN AND
FREEZING DRIZZLE IS POSSIBLE.
DRIER AIR WILL MOVE IN SLOWLY FROM THE WEST. THE BACK EDGE NOW
FROM FZY TO DSV. QUIET THIS EVENING BEFORE A COLD FRONT DROPS SE
THROUGH THE CWA LATE TONIGHT AND THU MORNING. SOME MOISTURE BUT
SNOW SHOWERS WILL BE LIGHT. 6 HOUR SNOWFALL AMOUNTS UNDER AN INCH.
&&
.SHORT TERM /6 AM THIS MORNING THROUGH SATURDAY/...
3 PM UPDATE...
WITH THE COLD FRONT THURSDAY HIGHS WILL BE IN THE MORNING WITH
CENT NY DROPPING IN THE AFTN. LAKE EFFECT WILL KICK IN BUT SHOULD
REMAIN WEAK INTO FRIDAY. SHEAR IS HIGH. THE SATURATED LEVEL IS
ONLY TO 5K TO START THEN LIFTS TO 7 THU NGT. A SHALLOW DENDRITE
ZONE AT THE TOP OF THE SATURATED LAYER WILL ALSO LIMIT SNOWFALL
THU. THU NGT LAKE EFFECT SHOULD BE BETTER BUT NW FLOW WILL MEAN
MULTIBANDS AND NO LAKE HURON CONNECTION. COLDER WITH BETTER
MOISTURE. THE COLDER AIR BRINGS THE DENDRITE ZONE DOWN SOLIDLY IN
THE DENDRITE ZONE. STILL A LOT OF SHEAR WITH HARDLY ANY SFC TO 2K
WINDS.
FRI AFTN INTO SAT THE LOW LEVEL WINDS SHIFT TO WEST SENDING THE
LAKE EFFECT INTO JUST ONEIDA. WAA STARTS KILLING THE LAKE EFFECT
FRI NGT, BUT NOT SOON ENOUGH TO GET FRI HIGH TEMPS ABOVE FREEZING.
HIGH PRESSURE SLIDES EAST FROM THE OHIO VALLEY FRI INTO THE
CAROLINAS FRI NGT.
A WARM FRONT AHEAD OF A SFC LOW MOVING EAST IN SE CANADA WILL
BRING SNOW SHOWERS ALONG THE LAKE SHORE LATE FRI AND FRI EVE. LOW
LEVEL FLOW CONTINUES OUT OF THE W AND SW SATURDAY SO MOST OF THE
CWA WILL BE DRY. WITH 850MB TEMPS APPROACHING ZERO HIGH TEMPS WILL
RISE INTO THE U30S AND L40S.
&&
.LONG TERM /SATURDAY NIGHT THROUGH WEDNESDAY/...
230 PM WED UPDATE...
HIGH CONFIDENCE IN AN ARCTIC SHIFT TO THE WEATHER PATTERN WITH
PERHAPS THE COLDEST AIR OF THE SEASON EN ROUTE. GFS AND ECMWF
AGREE ON 1000-500MB THICKNESSES DIPPING IN THE 490S FOR AT LEAST
CENTRAL NY AND CLOSE TO IT FOR NORTHEAST PA BY 12Z TUESDAY. THIS
BEGINS WITH INITIAL MOISTURE-LIMITED COLD FRONT PASSING THROUGH
EARLY SUNDAY WITH SOME SCATTERED SNOW SHOWERS...BRINGING
TEMPERATURES BACK TO NEAR NORMAL. ARCTIC FRONT THEN DROPS THROUGH
MONDAY TO SEND TEMPERATURES WELL BELOW CLIMATOLOGY EARLY NEXT WEEK.
LAKE EFFECT DETAILS AND PRESENCE OF CLIPPER-LIKE SYSTEMS WITHIN
BRISK UPPER FLOW HAVE YET TO BE SORTED OUT...YET VERY DRY AIR MASS
OVERALL...SO FOR NOW WENT ALONG WITH HPC POPS GENERALLY IN SLIGHT
TO LOW CHANCE RANGE /POPS HIGHEST WITH ARCTIC FRONT MONDAY IN
30-50 PCT RANGE/. WITH 850MB TEMPERATURES PUSHING AROUND MINUS-20
CELSIUS BY TUESDAY...JUST ABOUT ANY PASSING CLOUD WILL AT LEAST
PRODUCE LIGHT SCATTERED FLURRIES WITH ABOUT THE SAME WATER CONTENT
AS STYROFOAM.
&&
.AVIATION /06Z THURSDAY THROUGH MONDAY/...
ARCTIC FNT WILL DROP THRU THE AREA AFT 12Z AND TRIGGER SOME SNOW
SHWRS WITH A BRIEF PD OF LE BHD THE FNT. THIS WILL DROP CIGS AND
VSBYS INTO THE MVFR RANGE MOST STATIONS...WITH SOME BRIEF IFR
CONDS PSBL. WLY WINDS HAD OF THE FNT WILL BECOME NLY BHD THE
FNT...THEN BECOME LGT AFT 00Z AS HIPRES BLDS IN.
.OUTLOOK...
THU NGT THRU FRI...MAINLY MVFR CIGS AND SOME SCT -SHSN IN CNTRL
NY...VFR AVP.
FRI NGT/SAT...MAINLY VFR.
SAT NGT THRU MON...MVFR/IFR IN SNOW SHOWERS...ESPECIALLY CNTRL NY.
&&
.BGM WATCHES/WARNINGS/ADVISORIES...
PA...NONE.
NY...NONE.
&&
$$
SYNOPSIS...MDP/PVN
NEAR TERM...PVN/TAC
SHORT TERM...TAC
LONG TERM...MDP
AVIATION...DGM/DJP
AREA FORECAST DISCUSSION
NWS GRAND FORKS ND
344 AM CST THU JAN 17 2013
.SHORT TERM...
WATER VAPOR SHOWS THE RIGHT FRONT OF A 300 MB 150KT JET OVER NE
ND/NW MN THIS MORNING. A COUPLE OF WEAK 500 MB SHORT WAVES ON THE
SOUTH EDGE OF JET MAX FROM SRN SASK INTO CNTRL-SE ND. ONCE WEAK
SYSTEM MOVING THRU ERN ND ATTM INTO WCNTRL MN PRODUCING SOME
FLURRIES. MAIN RESULT OF JET MAX IS TO PRODUCE AN EXPANSIVE CLOUD
SHIELD WHICH HAS MOVED OVER ALL OF THE FCST AREA OVERNIGHT CAUSING
RISING TEMPS IN NW MN WHICH DID DROP INTO THE MID TEENS BELOW
EARLY THIS EVE. AS A RESULT OF WARMING TEMPS AND LIGHT WINDS HAVE
CANCELLED WIND CHILL ADV.
SHORT TERM MODELS SUCH AS THE RAP INSIST SOME CLEARING WILL MOVE
INTO FAR NE ND AND NW MN LATER THIS MORNING AND AFTN AND SOME
CLEARING IS NOTED IN PATCHY FASION MOVING INTO SW MANITOBA ATTM
FROM CNTRL SASK. THUS SOME SUN PSBL LATER TODAY.
TEMPS A REAL CONCERN THRU THE PD. SFC MAP SHOWS A WK LOW NR DVL
MOVING SOUTHEAST ALONG A THERMAL BOUNDARY FROM SE SASK INTO SE
ND...NR AN ESTEVAN TO MINOT TO JAMESTOWN TO ABERDEEN LINE. TEMPS
INTO THE TEENS IN THE FAR WRN FCST AREA ATTM AND EXPECT AS WINDS
TURN A BIT MORE NORTH AFTER SUNRISE TEMPS TO FALL A BIT. REST OF
THE FCST AREA TO REMAIN CHILLY WITH HIGHS TODAY IN THE SINGLE
DIGITS...WITH TEMPS STRUGGLING TO REACH ZERO IN FAR NORTHEAST FCST
AREA WHERE COLDEST AIRMASS RESIDES.
TONIGHT WILL SEE NEXT SHORT WAVE WHICH WILL MOVE INTO CNTRL
ALBERTA MOVE SOUTHEAST. THIS SYSTEM WILL BE MORE PRESENT AT THE
925-850 MB LEVEL WHERE LOWER LEVEL WARM ADVECTION ZONE WILL
STRENGTHEN TONIGHT FROM WRN MANITOBA INTO ERN ND/NW MN. THUS DO
LOOK FOR A BAND OF WARM ADV SNOW TO EXPAND SOUTHEAST INTO DVL
BASIN BEFORE 06Z AND THEN SPREAD EAST OVERNIGHT...WITH WARM ADV
MAXIMIZING IN NW MN LATE TONIGHT WHERE 1-2 INCHES OF SNOW MAY FALL
UP IN THE ROSEAU-WARROAD-BAUDETTE AREAS. STRONG WARMING AT THE SFC
TO AS WINDS TURN SOUTHERLY AND INCREASE TO 10 TO 20 KTS. AS WHAT
OCCURRED A FEW DAYS AGO EXPECT RISING TEMPS OVER ERN ND TONIGHT
REACHING THE 20S. AIRMASS TO REMAIN RATHER MILD INTO FRIDAY AS
WELL SOUTH OF A STRONGER SHORT WAVE AND SFC LOW WHICH WILL MOVE
FROM NORTHERN ALBERTA SOUTHEAST TOWARD LAKE OF THE WOODS REGION
SATURDAY. SOME LIGHT SNOW WITH THIS SYSTEM AS WELL...BUT MOSTLY
OVER FAR NW MN INTO ONTARIO. TEMPS FRIDAY SOUTH OF THE LOW WILL
RISE INTO THE LOW-MID 30S AS 925 MB TEMPS RISE TO ABOVE ZERO IN
AREAS FROM DVL TO FARGO TO FERGUS FALLS SOUTHWARD.
SATURDAY PROMISES TO BE AN INTERESTING DAY AS SFC LOW MOVES FROM
LAKE OF THE WOODS REGION SOUTHEAST AND IN ITS WAKE WILL BE STRONG
COLD ADVECTION WITH 925 MB TEMPS DROPPING SOME 20 DEGREES DURING
THE DAY SATURDAY WITH 25 TO 30 KT SFC WINDS FROM THE NORTH. HOURLY
TEMPS A REAL HEADACHE AS COULD WELL BE IN THE 20S TO START IN SE
ND/WCNTRL MN...BUT ALL AREAS WILL SEE FALLING TEMPS INTO THE
SINGLE DIGITS ABOVE AND BELOW ZERO IN THE AFTN WITH WIND CHILLS IN
THE TEENS AND 20S BELOW.
HIGH PRESSURE WILL MOVE IN SAT NIGHT WITH LIGHTER WINDS AND MAYBE
A PERIOD OF RATHER CLEAR SKY ESP IN THE EVENING. THIS SHOULD ALLOW
FOR WIDESPREAD TEENS BLO ZERO...BUT CLOUDS IN ADVANCE OF THE NEXT
SYSTEM DUE TO ARRIVE SUNDAY WILL LIKELY PREVENT ANY HUGE TEMP
DROP.
.LONG TERM (SUNDAY-WEDNESDAY)...
THE 00Z GFS/ECMWF/GEM ARE ALL IN GOOD AGREEMENT THROUGH MUCH OF THE
PERIOD WITH THE OVERALL SYNOPTIC PATTERN EVOLUTION. STRONGLY
MERIDIONAL NORTHWESTERLY FLOW ALOFT IN RESPONSE TO HIGH AMPLITUDE
RIDGING ACROSS WESTERN NORTH AMERICA WILL DRIVE ARCTIC AIR SOUTH ACROSS
THE NORTHERN PLAINS. BOTH THE GFS/ECMWF SHOW 925 MB TEMPS FALLING
INTO THE -25C TO -30C RANGE BY 12Z MONDAY...BEFORE SLOW MODIFICATION
OF THE AIR MASS TAKES PLACE BY THE END OF THE PERIOD AS THE UPPER
AIR PATTERN BEGINS TO DE-AMPLIFY AND THICKNESSES RISE. HIGH TEMPS
WILL GENERALLY BE BELOW ZERO IN MOST AREAS SUNDAY AND
MONDAY...RECOVERING INTO THE SINGLE DIGITS AND TEENS BY WEDNESDAY.
LOW TEMPS LIKELY WILL DEPEND ON CLOUDS AND SFC HIGH POSITION TO SOME
DEGREE...BUT TEMPS DOWN TO NEAR OR BELOW -20F EXPECTED IN MANY AREAS
ON SUNDAY NIGHT AND AGAIN IN SOME AREAS ON MONDAY NIGHT.
AS HAS BEEN THE CASE RECENTLY WITHIN THE NORTHWEST FLOW ALOFT...WEAK
EMBEDDED WAVES MAY BRING PERIODIC CHANCES FOR LIGHT SNOW AND
FLURRIES...BUT THE TIMING AND LOCATION OF THESE SYSTEMS IS UNCERTAIN
AT THIS RANGE. MAINTAINED LOW POPS FOR SUNDAY WITH ONE SYSTEM
DROPPING OUT OF CANADA. SOME INDICATION OF ANOTHER WEAK SYSTEM FOR
MONDAY NIGHT OR TUESDAY...BUT WILL STICK WITH DRY FORECAST FOR NOW
DUE TO LOW CONFIDENCE. OTHERWISE...A SERIES OF ARCTIC HIGHS DROPPING
SOUTH WILL RESULT IN FAIRLY TRANQUIL WEATHER FOR MUCH OF THE PERIOD.
&&
.AVIATION...
MIXED VFR AND MVFR CLOUD DECKS AROUND THIS MORNING WITH SOME
POTENTIAL FOR CLEARING INTO NE ND/NW MN LATER THIS MORNING THRU
THIS AFTN. WINDS WILL BE PRETTY LIGHT TODAY...GENERALLY 10 KTS OR
LESS...BUT MAY BE MORE VARIABLE IN DIRECTION DUE TO RATHER WEAK
SFC FEATURES. WINDS WILL TURN SOUTHERY TONIGHT AND INCREASE TO THE
10 TO 20 KT RANGE IN THE RRV AND ERN ND. CLOUDS WILL SPREAD OVER
THE REGION AGAIN WITH LIGHT SNOW MOVING INTO DVL-GFK BY 06Z AND
THEN SPREADING EAST. SOME MVFR CIGS AND VSBYS PSBL WITH THIS
SYSTEM.
&&
.FGF WATCHES/WARNINGS/ADVISORIES...
ND...NONE.
MN...NONE.
&&
$$
RIDDLE/MAKOWSKI
AREA FORECAST DISCUSSION
NWS BISMARCK ND
1129 PM CST WED JAN 16 2013
.DISCUSSION...LATEST SURFACE MAP SHOWS A STATIONARY FRONT STRETCHING
FROM MOOSE JAW IN CANADA...SOUTHEAST TO WILLISTON...DICKINSON AND
CURVING INTO PIERRE SOUTH DAKOTA. 925MB ISOTHERM STRUCTURE ON THE
NAM AND HOURLY RAP MODEL CLEARLY SHOW THE BAROCLINIC BOUNDARY
DEFINING THIS FRONT. TWO WAVES OF LOW PRESSURE WERE OBSERVED...ONE
NEAR KILLDEER IN DUNN COUNTY...AND THE SECOND FURTHER UPSTREAM
WEST OF CROSBY. MODEL GUIDANCE SUGGESTS RISING TEMPERATURES
OVERNIGHT FOR MANY LOCATIONS ALONG THE FRONT AND AHEAD OF THE
LOWS. THIS WOULD MAINLY AFFECT SOUTH CENTRAL NORTH DAKOTA. AS EACH
WAVE SLIDES ALONG THE BOUNDARY OVERNIGHT INTO THURSDAY
MORNING...THE BOUNDARY IS FORCED TO BULGE NORTHEAST...THUS
ALLOWING A WARM-UP FROM THE SFC-925MB...THEN QUICKLY COOLS DOWN
AGAIN AS THE LOW DEPARTS AND THE BAROCLINIC ZONE IS FORCED TO
RETREAT FURTHER SOUTHWEST. TEMPERATURES WILL BE A CHALLENGE
OVERNIGHT...VERY MUCH DEPENDENT ON THE POSITION OF THE SURFACE
LOWS AT EACH HOUR THROUGH 15Z THURSDAY. THIS TREND IS ALREADY
OCCURRING...AS KBIS HAS WARMED 4 DEGREES IN THE LAST 3HRS. THE
CHALLENGE WILL BE JUST HOW MUCH WARMING WILL OCCUR. THE RAP
SUGGESTS TEMPERATURES RISING TO AROUND 32F BY 12Z AT KBIS. WILL
BLEND THE CURRENT FORECAST WITH THE RAP WHICH WILL SHOW A WARMING
TREND TO AROUND 30 BY MORNING. ONCE THE SURFACE LOW SHIFTS TO THE
SOUTHEAST...TEMPERATURES WILL ACTUALLY FALL DURING THE 12Z TO 18Z
TIME FRAME. WILL ALSO CONTINUE WITH THE MENTION OF FLURRIES
OVERNIGHT WHERE THE BAROCLINIC ZONE AND SURFACE LOWS INTERACT.
CURRENT RADAR RETURNS REMAIN CONSISTENT WITH THIS IDEA.
&&
.AVIATION...A FRONTAL BOUNDARY WILL REMAIN SITUATED NORTHWEST TO
SOUTHEAST ACROSS THE FORECAST AREA TONIGHT. LOW PRESSURE SLIDING
SOUTHEAST ALONG THE BOUNDARY WILL PRODUCE AREAS OF MVFR CLOUDS AND
POSSIBLY A FEW PERIODS OF LIGHT SNOW...MAINLY FROM WILLISTON AND
MINOT SOUTHEAST TO BISMARCK AND JAMESTOWN. THE BOUNDARY WILL DROP
SOUTH ON THURSDAY WITH SURFACE FLOW TURNING MORE NORTHERLY EAST OF
THE BOUNDARY...AND A WESTERLY FLOW WEST OF THE BOUNDARY. THE
BOUNDARY WILL THEN LIFT NORTHEAST LATE THURSDAY AND THURSDAY NIGHT
AS A WARM FRONT. DEPICTING LOW CEILINGS WILL BE TROUBLESOME UNTIL
LATE IN THE FORECAST PERIOD WHEN THE BOUNDARY LIFTS NORTHEAST AND
DRIER AIR WORKS INTO THE AREA BEHIND THE WARM FRONT.
&&
.BIS WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
DISCUSSION...KS
AVIATION...TWH
AREA FORECAST DISCUSSION
NWS WILMINGTON OH
421 AM EST THU JAN 17 2013
.SYNOPSIS...
CLOUD COVER WILL CONTINUE FOR MUCH OF TODAY AS THE OHIO VALLEY
RESIDES BETWEEN LOW PRESSURE TO THE SOUTH...AND HIGH PRESSURE TO
THE WEST. THE HIGH WILL BUILD EASTWARD TONIGHT...BRINGING THE AREA
A PERIOD OF SEASONABLE TEMPERATURES AND FAIR WEATHER THROUGH
SATURDAY. SOME SNOW SHOWERS WILL BECOME POSSIBLE SATURDAY NIGHT AS
AN ARCTIC AIRMASS BEGINS TO MOVE INTO OUR REGION.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
A
AMPLE CLOUD COVER EXTENDS ACROSS THE AREA UNDER A DENSE HIGH CLOUD
CANOPY ASSOCIATED WITH A STRONG UPPER LEVEL JET. PATCHES OF LOW
CLOUDS ARE ALSO OCCURRING UNDER THIS DECK PRIMARILY ASSOCIATED WITH
MOIST LOW LEVEL NORTHERLY FLOW. MODELS ARE IN DISAGREEMENT ON HOW
TO HANDLE THIS LOW LEVEL MOISTURE AS WE GO THROUGH THE DAY. THE
HIGH CLOUDS WILL GRADUALLY SHIFT EAST AS THE JET MAX EXITS OUR
REGION TODAY. THE RAP INDICATES THAT MUCH OF THE LOW CLOUD COVER
WILL CONTINUE THROUGHOUT THE DAY. THE NAM SUGGESTS CLEARING THIS
AFTERNOON. FOLLOWING THE PERSISTENT TREND FOR THE PAST SEVERAL
DAYS...WILL BE PESSIMISTIC ABOUT CLEARING TODAY. THIS WILL RESULT
IN HIGH TEMPERATURES PEAKING IN THE MIDDLE 30S.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH SUNDAY/...
A WEAK COLD FRONT WILL PASS ACROSS THE AREA TONIGHT. THIS FRONT
WILL BE MOISTURE STARVED SO KEPT ANY MENTION OF FLURRIES...THAT
HI RES MODELS ARE SUGGESTING...OUT OF THE FORECAST. HIGH PRESSURE
WILL BEGIN TO BUILD BEHIND THIS WEAK FRONT LATE TONIGHT AND INTO
THE DAY FRIDAY. THIS SHOULD FINALLY PROVIDE FOR SOME CLEARING
SKIES...ESPECIALLY ACROSS THE SOUTH AND CLOSER TO THE RIDGE
CENTER. TEMPERATURES WILL REMAIN GENERALLY SEASONABLE THURSDAY
NIGHT AND FRIDAY.
BY FRIDAY NIGHT SOME RETURN FLOW WILL DEVELOP WITH THE LOW LEVEL
PRESSURE GRADIENT INCREASING AS THE RIDGE SHIFTS ACROSS THE
SOUTHEASTERN CONUS AND LOW PRESSURE BEGINS TO PUSH EASTWARD
ACROSS THE GREAT LAKES. WARMER TEMPERATURES MOVING IN AS WELL AS
WINDS KEEPING UP OVERNIGHT WILL LIKELY KEEP TEMPERATURES IN THE
UPPER 20S FOR THE MOST PART.
SURFACE GRADIENT WILL TIGHTEN FURTHER ON SATURDAY AS THE LOW
PASSES TO OUR NORTH WHICH WILL PROVIDE BREEZY SOUTHWEST WINDS AND
A RATHER MILD DAY. TEMPERATURES WILL LIKELY TOP OUT IN THE MIDDLE
40S ACROSS THE NORTH TO THE LOWER 50S ACROSS THE SOUTH.
A DEEP UPPER TROUGH BEGINS TO DIG SOUTH INTO OUR REGION SATURDAY
NIGHT AS THE SURFACE LOW REACHES THE EASTERN GREAT LAKES. AS THIS
OCCURS...AN ARCTIC COLD FRONT WILL ARRIVE AT OUR DOORSTEP. SOME
LIGHT PRECIPITATION IN THE FORM OF SNOW SHOWERS LOOKS
POSSIBLE BEHIND THIS FRONT...ESPECIALLY ACROSS THE NORTHERN
PORTIONS OF THE FORECAST AREA. BEHIND THIS STRONG COLD
FRONT...BREEZY NORTHWEST WINDS WILL BRING MUCH COLDER AND DRIER
AIR ACROSS THE REGION SUNDAY.
&&
.LONG TERM /SUNDAY NIGHT THROUGH WEDNESDAY/...
WEAK SHORT WAVES WILL BRING A SLIGHT CHANCE FOR SNOW SHOWERS ON
MONDAY AND AGAIN ON TUESDAY NIGHT. OTHERWISE...PRECIPITATION IS
NOT EXPECTED IN THE MODIFIED ARCTIC AIRMASS.
ABOVE NORMAL HIGHS ARE EXPECTED FOR SATURDAY IN A BRIEF ROUND OF
WARM ADVECTION AND SOLAR HEATING. IN THE COLDER AIRMASS THAT WILL BE
AROUND FOR THE REST OF THE PERIOD...TEMPERATURES WILL BE WELL BELOW
NORMAL. TUESDAY MAY BE THE COLDEST DAY...WITH HIGHS NOT FORECAST TO
REACH 20 IN MOST LOCATIONS.
&&
.AVIATION /10Z THURSDAY THROUGH MONDAY/...
A WEAKENING FRONTAL BOUNDARY WILL PUSH DOWN ACROSS THE REGION
THROUGH THIS MORNING. AS IT DOES...A SC FIELD WILL OVERSPREAD THE
TAF SITES OVER THE NEXT FEW HOURS. THE SOUTHERN EDGE OF THIS IS
STILL VFR...BUT WE WILL LIKELY SEE SOME MVFR CIGS DEVELOP THROUGH
DAYBREAK...ESPECIALLY AT THE NORTHERN TAF SITES. DRIER AIR WILL
WORK IN FROM THE NORTHWEST THROUGH MID TO LATE MORNING. THIS
SHOULD ALLOW LOWER CLOUDS TO SCATTER OUT WITH VFR CONDITIONS
EXPECTED THROUGH THE REMAINDER OF THE TAF PERIOD.
OUTLOOK...NO SIGNIFICANT WEATHER IS EXPECTED.
&&
.ILN WATCHES/WARNINGS/ADVISORIES...
OH...NONE.
KY...NONE.
IN...NONE.
&&
$$
SYNOPSIS...LATTO
NEAR TERM...LATTO
SHORT TERM...LATTO
LONG TERM...CONIGLIO
AVIATION...JGL
AREA FORECAST DISCUSSION
NWS WILMINGTON OH
330 AM EST THU JAN 17 2013
.SYNOPSIS...
CLOUD COVER WILL CONTINUE FOR MUCH OF TODAY AS THE OHIO VALLY
RESIDES BETWEEN LOW PRESSURE TO THE SOUTH...AND HIGH PRESSURE TO
THE WEST. THE HIGH WILL BUILD EASTWARD TONIGHT...BRINGING THE AREA
A PERIOD OF SEASONABLE TEMPERATURES AND FAIR WEATHER THROUGH
SATURDAY. SOME SNOW SHOWERS WILL BECOME POSSIBLE SATURDAY NIGHT AS
AN ARCTIC AIRMASS BEGINS TO MOVE INTO OUR REGION.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...A
AMPLE CLOUD COVER EXTENDS ACROSS THE AREA UNDER A DENSE HIGH CLOUD
CANOPY ASSOCIATED WITH A STRONG UPPER LEVEL JET. PATCHES OF LOW
CLOUDS ARE ALSO OCCURRING UNDER THIS DECK PRIMARILY ASSOCIATED WITH
MOIST LOW LEVEL NORTHERLY FLOW. MODELS ARE IN DISAGREEMENT ON HOW
TO HANDLE THIS LOW LEVEL MOISTURE AS WE GO THROUGH THE DAY. THE
HIGH CLOUDS WILL GRADUALLY SHIFT EAST AS THE JET MAX EXITS OUR
REGION TODAY. THE RAP INDICATES THAT MUCH OF THE LOW CLOUD COVER
WILL CONTINUE THROUGHOUT THE DAY. THE NAM SUGGESTS CLEARING THIS
AFTERNOON. FOLLOWING THE PERSISTENT TREND FOR THE PAST SEVERAL
DAYS...WILL BE PESSIMISTIC ABOUT CLEARING TODAY. THIS WILL RESULT
IN HIGH TEMPERATURES PEAKING IN THE MIDDLE 30S.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH SUNDAY/...
A WEAK COLD FRONT WILL PASS ACROSS THE AREA TONIGHT. THIS FRONT
WILL BE MOISTURE STARVED SO KEPT ANY MENTION OF FLURRIES...THAT
HI RES MODELS ARE SUGGESTING...OUT OF THE FORECAST. HIGH PRESSURE
WILL BEGIN TO BUILD BEHIND THIS WEAK FRONT LATE TONIGHT AND INTO
THE DAY FRIDAY. THIS SHOULD FINALLY PROVIDE FOR SOME CLEARING
SKIES...ESPECIALLY ACROSS THE SOUTH AND CLOSER TO THE RIDGE
CENTER. TEMPERATURES WILL REMAIN GENERALLY SEASONABLE THURSDAY
NIGHT AND FRIDAY.
BY FRIDAY NIGHT SOME RETURN FLOW WILL DEVELOP WITH THE LOW LEVEL
PRESSURE GRADIENT INCREASING AS THE RIDGE SHIFTS ACROSS THE
SOUTHEASTERN CONUS AND LOW PRESSURE BEGINS TO PUSH EASTWARD
ACROSS THE GREAT LAKES. WARMER TEMPERATURES MOVING IN AS WELL AS
WINDS KEEPING UP OVERNIGHT WILL LIKELY KEEP TEMPERATURES IN THE
UPPER 20S FOR THE MOST PART.
SURFACE GRADIENT WILL TIGHTEN FURTHER ON SATURDAY AS THE LOW
PASSES TO OUR NORTH WHICH WILL PROVIDE BREEZY SOUTHWEST WINDS AND
A RATHER MILD DAY. TEMPERATURES WILL LIKELY TOP OUT IN THE MIDDLE
40S ACROSS THE NORTH TO THE LOWER 50S ACROSS THE SOUTH.
A DEEP UPPER TROUGH BEGINS TO DIG SOUTH INTO OUR REGION SATURDAY
NIGHT AS THE SURFACE LOW REACHES THE EASTERN GREAT LAKES. AS THIS
OCCURS...AN ARCTIC COLD FRONT WILL ARRIVE AT OUR DOORSTEP. SOME
LIGHT PRECIPITATION IN THE FORM OF SNOW SHOWERS LOOKS
POSSIBLE BEHIND THIS FRONT...ESPECIALLY ACROSS THE NORTHERN
PORTIONS OF THE FORECAST AREA. BEHIND THIS STRONG COLD
FRONT...BREEZY NORTHWEST WINDS WILL BRING MUCH COLDER AND DRIER
AIR ACROSS THE REGION SUNDAY.
&&
.LONG TERM /SUNDAY NIGHT THROUGH WEDNESDAY/...
WEAK SHORT WAVES WILL BRING A SLIGHT CHANCE FOR SNOW SHOWERS ON
MONDAY AND AGAIN ON TUESDAY NIGHT. OTHERWISE...PRECIPITATION IS
NOT EXPECTED IN THE MODIFIED ARCTIC AIRMASS.
ABOVE NORMAL HIGHS ARE EXPECTED FOR SATURDAY IN A BRIEF ROUND OF
WARM ADVECTION AND SOLAR HEATING. IN THE COLDER AIRMASS THAT WILL BE
AROUND FOR THE REST OF THE PERIOD...TEMPERATURES WILL BE WELL BELOW
NORMAL. TUESDAY MAY BE THE COLDEST DAY...WITH HIGHS NOT FORECAST TO
REACH 20 IN MOST LOCATIONS.
&&
.AVIATION /08Z THURSDAY THROUGH MONDAY/...
A WEAKENING FRONTAL BOUNDARY WILL PUSH DOWN ACROSS THE REGION
THROUGH THIS MORNING. AS IT DOES...A SC FIELD WILL OVERSPREAD THE
TAF SITES OVER THE NEXT FEW HOURS. THE SOUTHERN EDGE OF THIS IS
STILL VFR...BUT WE WILL LIKELY SEE SOME MVFR CIGS DEVELOP THROUGH
DAYBREAK...ESPECIALLY AT THE NORTHERN TAF SITES. DRIER AIR WILL
WORK IN FROM THE NORTHWEST THROUGH MID TO LATE MORNING. THIS
SHOULD ALLOW LOWER CLOUDS TO SCATTER OUT WITH VFR CONDITIONS
EXPECTED THROUGH THE REMAINDER OF THE TAF PERIOD.
OUTLOOK...NO SIGNIFICANT WEATHER IS EXPECTED.
&&
.ILN WATCHES/WARNINGS/ADVISORIES...
OH...NONE.
KY...NONE.
IN...NONE.
&&
$$
SYNOPSIS...LATTO
NEAR TERM...LATTO
SHORT TERM...LATTO
LONG TERM...CONIGLIO
AVIATION...JGL
AREA FORECAST DISCUSSION
NWS GREENVILLE-SPARTANBURG SC
102 AM EST THU JAN 17 2013
.SYNOPSIS...
A COLD FRONT WILL CONTINUE TO DRIFT SLOWLY THROUGH THE REGION
INTO TONIGHT. LOW PRESSURE IS FORECAST DEVELOP OVER THE EASTERN GULF
OF MEXICO AND MOVE NORTHEAST ALONG THE FRONT ON THURSDAY. AS THE LOW
MOVES OFF THE NORTH CAROLINA COAST THURSDAY NIGHT...THE WEATHER WILL
BE DRIER AND SEASONABLY COOL FOR THE WEEKEND.
&&
.NEAR TERM /UNTIL 6 AM THIS MORNING/...
AS OF MIDNIGHT...COLD WEDGE APPEARS TO BE HOLDING STRONG AND THIS
SHOULD LARGELY INHIBIT WARM AIR ALOFT FROM MAKING MUCH FURTHER PUSH
NORTHWARD INTO THE CWFA. RAP 925MB TEMP PROGS FOR THE REST OF THE
NIGHT SHOW SLIGHT WARMING IN THE COUNTIES NEAR/ALONG OUR SOUTHEAST
BORDER WHILE COLD ADVECTION IS CLEARLY GETTING UNDERWAY OVER THE
MTNS AND NRN NC PIEDMONT. TEMP/DEWPT TRENDS HAVE BEEN REVISED USING
THE RAP SFC TEMPS WHICH WERE IN FAIRLY GOOD AGREEMENT WITH 12 AM
ANALYZED OBS AND AGREE WITH THE 925MB PATTERN.
AS OF 10 PM...OVER THE COURSE OF THE EVENING I HAVE BEEN MONITORING
TRENDS IN THE MODEL GUIDANCE AND UPDATING THE FORECAST ACCORDINGLY.
TWO TRENDS HAVE OCCURRED...GUIDANCE IS WETTER AND SLIGHT QUICKER
WITH COOLING TEMPS LATE TOMORROW AFTERNOON AND EVENING. IN
SHORT...THE POTENTIAL FOR HEAVY SNOW HAS INCREASED ACROSS THE NC
MTNS...REMAINING AROUND THE SAME AS THE PREVIOUS PACKAGE EAST.
LATEST WATER VAPOR IMAGERY INDICATES THAT THE H5 LOW OVER ARKLATX
REGION HAS STARTED TO TRANSITION FROM A POSITIVE TILTED TROUGH TO
MORE NEUTRAL. AHEAD OF THE LOW...A RIBBON OF 1.2 INCH PW EXTENDED
FROM THE YUCATAN PENINSULA ACROSS THE FL PANHANDLE TO THE SOUTHERN
APPALACHIANS. THE PW VALUES ARE NEARLY 200 PERCENT OF NORMAL. AS THE
H5 LOW APPROACHES TONIGHT...A SFC LOW IS EXPECTED TO RAPIDLY DEEPEN
AND ORGANIZE ACROSS CENTRAL GA. AS THE LOW DEEPENS...LLVL FLOW WILL
INCREASE...SUPPORTING A WARM FRONT/WEDGE BOUNDARY ACROSS THE
PIEDMONT OF THE CAROLINAS. NAM12 INDICATES THAT A SW TO NE BAND OF
925-850MB FRONTOGENESIS WILL DEVELOP DURING THE PRE DAWN HOURS. IN
ADDITION...H7 QG UPWARD VERTICAL VELOCITIES WILL INCREASE TO NEAR 15
MBS/HR. THE COMBINATION OF RICH MOISTURE AND DEEPENING LIFT WILL
SUPPORT THE DEVELOPMENT OF A BAND OF MODERATE RAIN ACROSS THE
FOOTHILLS AND PIEDMONT LATE TONIGHT. TEMPERATURES MAY SLOWLY RISE OR
REMAIN STEADY OVERNIGHT...UNDER WAA ALOFT. PRECIP WILL FALL AS RAIN.
POPS WERE INCREASE OVERNIGHT.
DYNAMICS ACROSS THE SOUTHERN APPALACHIAN REGION WILL INCREASE
SHARPLY AFTER SUNRISE AS THE TILTED LOW PRESSURE SYSTEM BEGINS TO
MOVE EASTWARD. A WIDE DEFORMATION ZONE SHOULD PIVOT OVER THE NC MTNS
THROUGH MID DAY...THEN BEGIN TO SHIFT EAST DURING THE AFTERNOON AND
EVENING. BY 18Z...THE CORE OF H7 QG UPWARD VERTICAL VELOCITIES WILL
RAPIDLY INCREASE TO 40 MBS/HR AND TRACK SE TO NE ACROSS THE MIDDLE
OF THE FORECAST AREA...FRONTOGENESIS PEAKS DURING THIS PERIOD. IN
ADDITION...THE NAM12 INDICATES THAT A BROAD FIELD OF NEGATIVE
SATURATED GEO POTENTIAL VORTICITY WILL DEVELOP AHEAD OF H7
LOW...POSSIBLY SIGNALING THE EXISTENCE OF INSTABILITY. GIVEN THE
ENVIRONMENT AND DURATION OF STRONG FORCING...I UPDATE THE FORECAST
TO INCREASE QPF BY AN INCH...INCREASE POPS TO 100 PERCENT.
TEMPERATURES ARE VERY CHALLENGING...BUT I ADJUST CONTINUOUS COOLING
TREND WITH THE NAM 2M TEMPS. USING THIS APPROACH...PRECIP SHOULD
BEGIN TO TRANSITION TO SN/IP ACROSS THE TN BORDER AFTER 18Z. THE
SNOW LINE WILL ADVANCE TO THE FOOTHILLS BY 0Z.
THE GFS AND NAM INDICATE THAT THE DEFORMATION ZONE WILL REMAIN OVER
THE CWA THROUGH THURS EVENING...MOVING EAST OF THE CWA BY EARLY FRI
MORNING. TEMPERATURES WILL DECREASE STEADILY THROUGH THE PERIOD.
HOWEVER...IT APPEARS THAT ONLY A 3 TO 6 HOUR WINDOW WILL EXIST EAST
OF THE MTNS FOR ACCUMULATING SN...GIVEN THE RAPID DECREASE IN
MOISTURE ALOFT AND FORCING. I HAVE UPDATED THE STORM TOTAL SNOW
FORECAST TO INCREASE SNOWFALL ACROSS THE MTNS BY A COUPLE OF
INCHES...AREAS EAST REMAIN VERY SIMILAR TO THE PREVIOUS FORECAST.
THE WINTER STORM PRODUCTS AND FLOOD WATCH APPEAR TO BE WELL PLACED
AND TIMED.
&&
.SHORT TERM /6 AM THIS MORNING THROUGH 6 PM FRIDAY/...
AS OF 315 PM WEDNESDAY...A NE TO SW ORIENTED DEEP LAYER FRONTAL
BOUNDARY REMAINS STALLED OVER THE WESTERN CAROLINAS AND NE GA. PW
VALUES ALONG THE BNDRY CONTINUE TO RUN 200 TO 300 PERCENT OF NORMAL.
IN FACT...NESTS MENTIONED THIS MORNING THAT FFC/S SOUNDING THIS
MORNING HAD IT/S 4TH HIGHEST RECORDED JANUARY PW VALUE. SO THAT SAY
THAT THERE IS A SIGNIFICANT AMOUNT OF MOISTURE IN PLACE OVER THE
REGION IS AN UNDERSTATEMENT. A POTENT UPPER LOW OVER ERN TX THIS
EVENING WILL TAKE ON A NEGATIVE TILT AND LIFT ACROSS THE UPSTATE BY
TOMORROW EVENING. THE NUMERICAL MODELS GENERATE VERY HEAVY RAIN WITH
THIS FEATURE. QPF AVERAGES AROUND 3 INCHES OVER MUCH OF THE SRN AND
ERN NC MTNS...THE FOOTHILLS AND THE WESTERN PIEDMONT. CONSIDERING
THE AMAZING AMOUNT OF RAIN SOME MOUNTAIN LOCATIONS HAVE HAD OVER THE
PAST THREE DAYS...THIS EXTRA SHOT OF RAIN IS LIKELY TO CAUSE A
CONSIDERABLE AMOUNT OF STREAM AND RIVER FLOODING. THEREFORE THE
FLOOD WATCH WILL BE EXPANDED ACROSS THE REST OF THE MOUNTAINS AND
FOOTHILLS OF THE WESTERN CAROLINAS AND NORTHEAST GEORGIA. WE COULD
SEE SOME VERY HIGH RAINFALL RATES AS THE WARM CONVEYOR BELT WORKS
ACROSS THE FA DURING THE DAYTIME TMRW. A TSTM ISN/T OUT OF THE
QUESTION. CONSIDERING THE EXPECTED RATES...SOME OF THE FLOODING MAY
BE MORE OF THE FLASH FLOOD VARIETY. IN FACT...I/M STILL DEBATING IF
WE WILL ISSUE THE NEW WATCH AS A FLOOD OR FLASH FLOOD PRODUCT.
THE OTHER CONCERN AS THE LOW PASSES WILL BE SNOWFALL. THE AIRMASS
AHEAD OF THE LOW IS VERY WARM AND MOIST. IT WILL TAKE A WHILE FOR
THE PCPN TO CHANGE OVER TO SNOW. I WOULDN/T EXPECT ANY SNOW TO
DEVELOP UNTIL 18 TO 21 UTC ACROSS THE HIGHER MOUNTAIN ELEVATIONS.
THE SNOW LEVELS WILL THEN QUICKLY DROP AND WORK EASTWARD WITH TIME.
THE SREF PLUME DIAGRAMS ARE SHOWING WINTER STORM CRITERIA SNOWFALL
AT ASHEVILLE AND EVEN AT HICKORY. I HAVE UPGRADED THE WINTER STORM
WATCH TO A WARNING ACROSS MOST OF THE NC MTNS. OVER THE SOUTHWEST
MOUNTAINS THE WARMING WILL BE IN EFFECT FOR ELEVATIONS ABOVE 3500
FEET. BY THE TIME THE SNOW LEVEL MAKES IT TO THE VALLEY FLOORS IN
THOSE AREAS...I EXPECT THE HEAVIEST PCPN WILL HAVE ENDED.
THE NORTHERN MOST PART OF THE UPSTATE AND NE GA HAVE BEEN INCLUDED
IN A WINTER WEATHER ADVISORY FOR TOMORROW NIGHT. ONLY AROUND AN INCH
OF SNOW IS IN THE GRIDS...BUT IF THE NAM/S STRONGER...SLOWER AND
COLDER DEFORMATION ZONE VERIFIES...WE COULD SEE HEAVIER HEAVIER SNOW
IN THESE LOCATIONS IN WELL. I AM MORE CONFIDENT IN THE NAM TONIGHT
AS THE IT AND THE GFS HAVE COME INTO MUCH BETTER AGREEMENT. OVER THE
NORTH CAROLINA ZONES...THE NAM AND MANY SREF MEMBERS INDICATE A
PERIOD OF SNOW ACROSS THE FOOTHILLS AND PIEDMONT DURING THE EVENING
HOURS. A CROSS SECTION THROUGH THE NAM SHOWS A DEEP LAYER NEGATIVE
EPV FROM 00-03 UTC. THIS IMPLIES THE POTENTIAL FOR HEAVY BANDED
PRECIPITATION WHICH WILL HELP TO LOWER SNOW LEVELS. IN FACT...AT
THIS POINT I/D SAY CONFIDENCE IS GOOD THAT PARTS OF THE PIEDMONT
WILL SEE SNOW...THOUGH ACCUMULATING SNOW MAY BE CONFINED TO A NARROW
BAND UNDER THE BEST CSI. THE RALEIGH OFFICE IS THINKING ALONG THE
SAME LINES AND WE HAVE ISSUED A WINTER STORM WATCH FOR THESE AREAS
STARTING AT 21 UTC TOMORROW. EVEN WITH WARM GROUND...HEAVY SNOWFALL
RATES COULD CAUSE TRAVEL CONCERNS AND MAY BREAK SOME LIMBS CAUSING
POWER OUTAGES.
&&
.LONG TERM /FRIDAY NIGHT THROUGH WEDNESDAY/...
AS OF 230 PM WEDNESDAY...A BROAD TROUGH WILL BE IN PLACE ACROSS THE
ERN CONUS THROUGH THE WEEKEND AS A SHARP WAVE ROUNDS THE POLAR
VORTEX AND CROSSES THE GREAT LAKES. A COLD FRONT WILL MOVE THROUGH
THE REGION ON SUNDAY...BUT IT SHOULD BE DRY OTHER THAN SHALLOW W TO
NW UPSLOPE FLOW MOISTURE INTO THE WRN MTNS PRODUCING SOME CLOUDS
LATE SUNDAY.
REINFORCING ENERGY WILL DIVE SE THROUGH THE MIDWEST ON MON AND PASS
MAINLY N OF THE FORECAST AREA MON NIGHT THROUGH TUE. BRIEFLY COUPLED
JET DIVERGENCE WILL BE POSSIBLE DURING THE MON NIGHT TIME
FRAME...BUT MOISTURE WILL BE TOO SHALLOW FOR ANYTHING OTHER THAN
SLIGHT CHANCES OF UPSLOPE SNOW SHOWERS IN THE WRN MTNS. REINFORCING
ARCTIC AIR WILL THEN ARRIVE BEHIND THE FRONT EARLY TUE THROUGH
WED...WITH DEEP LAYER NW FLOW THROUGH THE PERIOD ALONG WITH DRY
CONDITIONS.
&&
.AVIATION /06Z THURSDAY THROUGH MONDAY/...
AT KCLT AND KHKY...THE FIRST 6 HOURS OR SO OF THE PERIOD WILL LIKELY
BE MARKED BY VERY MESSY CONDITIONS...WITH CIGS AND VISBY BOUNCING
BACK AND FORTH BETWEEN VARIOUS FLT CATEGORIES. TOWARD DAYBREAK...
CONDITIONS SHOULD SETTLE INTO THE IFR/LIFR RANGE...AS STRONG LOW
LEVEL LIFT DEVELOPS IN RESPONSE TO STRONG UPPER LEVEL STORM SYSTEM
MOVING OUT OF THE LOWER MISS VALLEY. IN THE INTERIM...ONE AREA OF
LIGHT/MOD RAIN WILL PUSH EAST OF THE TERMINALS BY AROUND 07Z.
HOWEVER...ANOTHER ONE WILL APPROACH BETWEEN 09 AND 10Z. WHILE VISBY
WILL LIKELY IMPROVE IN BETWEEN THESE WAVES OF PRECIP...THE GENERAL
IDEA IS THAT CIGS WILL REMAIN (OR RETURN TO) LIFR. VERY POOR FLT
CONDITIONS ARE EXPECTED TO CONTINUE THROUGH THE DAY. PERIODS OF
HEAVY RAIN ARE EXPECTED DURING THE DAYLIGHT HOURS...LIKELY RESULTING
IN LONG DURATION OF IFR/LIFR VISBY. STRENGTHENING NE WINDS WILL
DEVELOP AS LOW PRESSURE INTENSIFIES TO THE SOUTHWEST...WITH GUSTS IN
THE 20S LIKELY BY AFTERNOON. FINALLY...RAIN IS EXPECTED TO CHANGE TO
SNOW THURSDAY EVENING...WITH LIGHT ACCUMULATIONS POSSIBLE...ESP AT
KHKY.
ELSEWHERE...ONE WAVE OF LIGHT/MOD RAIN HAS SHIFTED EAST OF THE
TERMINALS...BUT ANOTHER WILL MOVE BACK OVER THE AREA BETWEEN 7 AND 9
Z. VISBY IS EXPECTED TO BRIEFLY IMPROVE TO VFR PRIOR TO THE ARRIVAL
OF THE NEXT WAVE. HOWEVER...CIGS ARE A BIT MORE PROBLEMATIC. THE
IMPROVEMENT IN CIGS THAT WAS OBSERVED EARLIER WAS TIED TO THE ONSET
OF PRECIP...AND CIGS MAY VERY WELL RETURN TO LIFR/IFR PRIOR TO THE
ONSET OF PRECIP. CIGS ARE THEN EXPECTED TO BOUNCE AROUND BETWEEN FLT
CATEGORIES UNTIL AROUND SUNRISE...WHEN STRONG LOW LEVEL LIFT
DEVELOPS IN RESPONSE TO STRONG UPPER LEVEL STORM SYSTEM MOVING OUT
OF THE LOWER MISS VALLEY. THIS SHOULD RESULT IN CIGS SETTLING TO THE
IFR/LIFR RANGE...LASTING THROUGH THE DAY. PERIODS OF HEAVY RAIN ARE
EXPECTED DURING THE DAYLIGHT HOURS...LIKELY RESULTING IN LONG
DURATION OF IFR/LIFR VISBY. STRENGTHENING N/NE WINDS WILL DEVELOP AS
LOW PRESSURE INTENSIFIES TO THE SOUTHWEST...WITH GUSTS IN THE 20S
LIKELY BY AFTERNOON.THE OTHER ITEM OF CONCERN IS THAT RAIN WILL
CHANGE TO SNOW AT KAVL BY 00Z. ACCUMULATING SNOWFALL IS LIKELY. THE
UPSTATE TERMINALS MAY ALSO SEE SOME FLAKES AS WELL BEFORE THE PRECIP
ENDS THURSDAY EVENING...BUT LITTLE OR NO ACCUMULATIONS IS
EXPECTED.
OUTLOOK...DRY HIGH PRESSURE WILL BEGIN BUILDING OVER THE REGION
FRIDAY AND WILL REMAIN THROUGH THE WEEKEND.
AN EXPERIMENTAL AVIATION FORECAST CONSISTENCY TABLE SHOWING THE
PERCENTAGE OF GUIDANCE MEMBERS AGREEING WITH THE SCHEDULED ISSUANCE
CATEGORY IS AVAILABLE AT THE FOLLOWING LINK (USE LOWER CASE)...
WWW.WEATHER.GOV/GSP/AVIATION_TABLES
&&
.GSP WATCHES/WARNINGS/ADVISORIES...
GA...FLOOD WATCH THROUGH THIS EVENING FOR GAZ010-017-018-026-028.
WINTER WEATHER ADVISORY FROM 1 PM THIS AFTERNOON TO MIDNIGHT
EST TONIGHT FOR GAZ010-017.
NC...FLOOD WATCH THROUGH THIS EVENING FOR NCZ033-035-048>053-058-
059-062>065-501>510.
WINTER STORM WARNING FROM 1 PM THIS AFTERNOON TO MIDNIGHT EST
TONIGHT FOR NCZ033-048>050-052-053-064-065-501>507-509.
WINTER WEATHER ADVISORY FROM 1 PM THIS AFTERNOON TO MIDNIGHT
EST TONIGHT FOR NCZ051-058-059-062-063.
WINTER STORM WARNING FROM 7 AM THIS MORNING TO MIDNIGHT EST
TONIGHT FOR NCZ051-058-059-062-063.
WINTER STORM WATCH FROM THIS AFTERNOON THROUGH LATE TONIGHT
FOR NCZ035>037-056-057-068>072-508-510.
SC...FLOOD WATCH THROUGH THIS EVENING FOR SCZ001>007-010.
WINTER WEATHER ADVISORY FROM 1 PM THIS AFTERNOON TO MIDNIGHT
EST TONIGHT FOR SCZ001>003.
&&
$$
SYNOPSIS...CSH
NEAR TERM...NED/WIMBERLEY
SHORT TERM...MCAVOY
LONG TERM...HG
AVIATION...JDL
AREA FORECAST DISCUSSION
NWS NASHVILLE TN
1117 PM CST WED JAN 16 2013
.UPDATE...FOR 06Z AVIATION FORECAST
&&
.AVIATION...
WINTER STORM WATCH IN EFFECT FOR THE PLATEAU ON THURSDAY AS
FREEZING RAIN...SLEET AND SNOW WILL LIKELY IMPACT THE AREA.
THEREFORE POOR FLYING CONDITIONS WILL EXITS ALONG THE PLATEAU
BEGINNING AROUND 08Z AS CEILINGS AND VSBYS LOWER AND A MIX OF
LIGHT RAIN AND SLEET BEGINS. WINTER WEATHER WILL CONTINUE ALONG
THE PLATEAU DURING THE OVERNIGHT HOUR AND DURING THE DAY ON
THURSDAY.
AS FOR NASHVILLE NOT EXPECTING SIGNIFICANT PRECIP BUT WE COULD
SEE A MIX OF LIGHT RAIN AND SNOW FROM ABOUT MID MORNING THROUGH
NOON AND THEN A FEW FLURRIES IN THE AFTERNOON. MVFR CONDITIONS DUE
TO CEILINGS AND VSBYS WILL PREVAIL THROUGH A GOOD PART OF THE NEXT
24 HOURS.
CLARKSVILLE WILL LIKELY REMAIN VFR THROUGH A GOOD PART OF THE NEXT
24 HOURS WITH MVFR CONDITIONS POSSIBLE DUE TO CEILINGS FROM 15Z TO
ABOUT 18Z ON THURSDAY. FLURRIES ARE POSSIBLE IN THE AFTERNOON ON
THURSDAY.
GUSTY WINDS CAN BE EXPECTED ACROSS THE MID STATE FROM ABOUT MID-
DAY ON THROUGH THE AFTERNOON WITH SOME GUSTS OVER 20 KNOTS.
UPPER LOW OVER TEXARKANA WILL MOVE EASTWARD IN THE OVERNIGHT. 850
MILLIBAR LOW ABOUT JACKSON MISSISSIPPI. GOOD UPPER DIFFLUENCE
ACROSS THE TENNESSEE VALLEY WILL INCREASE IN THE OVERNIGHT AND ON
THURSDAY. LATEST RUC RUN HAS PRECIP BREAKING OUT SOUTHERN AND
EASTERN AREAS OF THE MID STATE AND ALONG THE PLATEAU. THIS IN LINE
WITH LATEST NSSL WRF RUN.
BOYD
&&
.PREV DISCUSSION... /ISSUED 946 PM CST WED JAN 16 2013/
UPDATE...
LATEST RADAR IMAGERY SHOWS RAIN HAS DIMINISHED IN COVERAGE AND
INTENSITY THIS EVENING WITH ONE MAIN BAND NOW EXTENDING FROM
NORTHWEST ALABAMA TO THE NORTHERN PLATEAU. HOWEVER...WATER VAPOR
IMAGERY DEPICTS A STRONG UPPER LEVEL LOW OVER EASTERN TEXAS THAT
WILL BE MOVING EASTWARD ACROSS THE GULF COAST STATES TO OUR SOUTH
TOMORROW. RAIN HAS ALREADY BEGUN DEVELOPING AND EXPANDING IN
COVERAGE ACROSS LOUISIANA AND MISSISSIPPI IN ASSOCIATION WITH THIS
SYSTEM...AND ADDITIONAL RAINFALL IS EXPECTED TO FORM LATE TONIGHT
AND SPREAD NORTHEASTWARD INTO OUR EASTERN ZONES. THERMAL PROFILES
WILL REMAIN TOO WARM FOR ANYTHING BUT RAIN TONIGHT EXCEPT
POSSIBLY ON THE FAR NORTHWEST EDGE OF THE PRECIPITATION WHERE A
VERY LIGHT RAIN/SNOW MIX HAS BEEN LEFT IN. HAVE UPDATED TEMPS AND
POPS FOR TONIGHT BASED ON THESE LATEST TRENDS.
AS UPPER LEVEL LOW MOVES TO OUR SOUTH DURING THE DAY ON
THURSDAY...A SURFACE LOW IS EXPECTED TO TAKE SHAPE AND DEEPEN OVER
THE CAROLINAS. CAA WILL CORRESPONDINGLY INCREASE ACROSS THE MID
STATE DURING THE DAY WITH GUSTY NORTH WINDS EXPECTED. AN
EXTENSIVE LOOK AT BUFKIT SOUNDINGS INDICATES THERMAL PROFILES WILL
BECOME FAVORABLE FOR A MIX OF RAIN AND SNOW...AND POSSIBLY
FREEZING RAIN AS WELL...OVER OUR PLATEAU COUNTIES THURSDAY MORNING
AS COLD AIR CONTINUES TO ADVECT SOUTHWARD...WITH A CHANGEOVER TO
ALL SNOW BY AFTERNOON AS SATURATED PROFILES FALL COMPLETELY BELOW
FREEZING. ALL PRECIP THEN EXITS THE AREA QUICKLY BY THURSDAY
EVENING AS SYSTEM SHIFTS OFF TO THE EAST.
SOME UNCERTAINTY REMAINS ON SNOW ACCUMS IN THE WSW AREA WITH BULK
OF PRECIP REMAINING TO OUR EAST AND CONCERNS WITH TIMING OF
CHANGEOVER AND SNOWFALL RATES. CURRENT REASONING IS CLOSEST TO A
BLEND OF HPC GUIDANCE WITH NAM/GFS SNOW ACCUMS...AND SHOWING A
GENERAL 1 TO 3 INCHES OF TOTAL SNOWFALL POSSIBLE ON THE
PLATEAU...WITH 4 INCH AMOUNTS NOT OUT OF THE QUESTION IN THE
TYPICALLY FAVORED AREAS OF HIGHER TERRAIN IN EASTERN
PUTNAM/CUMBERLAND/FENTRESS COUNTIES. SUCH AMOUNTS WOULD GENERALLY
BE A WINTER WEATHER ADVISORY TYPE EVENT...BUT WILL LET MID SHIFT
TAKE A LOOK AT 00Z GUIDANCE BEFORE DECIDING WHETHER AN ADVISORY OR
WARNING IS WARRANTED. ALSO APPEARS THERE WILL BE A SHARP CUTOFF TO
PRECIPITATION ON NORTHWEST EDGE OF PRECIP SHIELD PER 00Z NAM
AND MUCH OF MIDDLE TENNESSEE WEST OF THE CURRENT WSW AREA MAY BE
TOTALLY DRY TOMORROW...BUT WILL LEAVE LOW POPS IN FOR NOW.
UPDATED PRODUCTS WILL BE OUT SHORTLY.
PREV DISCUSSION... /ISSUED 649 PM CST WED JAN 16 2013/
UPDATE...FOR CSV AMENDMENT AT 170043Z
AVIATION...
TAKING A CLOSER LOOK AT THE FORECAST SOUNDING FOR CROSSVILLE HAVE
AMENDED TO INCLUDE A PERIOD OF FREEZING RAIN AND SLEET FROM 17/14Z
THROUGH ABOUT 17/18Z WITH SNOW BEGINNING BY 17/20Z. ICE ACCUMULATIONS ARE
LIKELY ALONG THE PLATEAU ON THURSDAY WITH SNOW ACCUMULATIONS OF 2
TO 4 INCHES POSSIBLE THURSDAY AFTERNOON.
BOYD
PREV DISCUSSION... /ISSUED 603 PM CST WED JAN 16 2013/
UPDATE...FOR 00Z AVIATION FORECAST
AVIATION...
CLOSED OFF UPPER LOW OVER NORTHEAST TEXAS THIS EVENING WILL SWING EAST
TONIGHT AND INTO MISSISSIPPI BY DAYBREAK THURSDAY. UPPER LOW WILL
MOVE EAST ACROSS ALABAMA AND INTO NORTHEAST GEORGIA BY EARLY THURSDAY
EVENING. MID STATE WILL BE ON THE COLD SIDE OF THIS SYSTEM WITH
GOOD COLD ADVECTION SPILLING IN DURING THE LATE MORNING AND MID
DAY ON THURSDAY. MORE RAIN TONIGHT AND THURSDAY MORNING ACROSS
SOUTHERN AND EASTERN AREAS WILL CHANGE TO SNOW OVER EASTERN AREAS
AND ALONG THE PLATEAU AROUND MID DAY THURSDAY WITH ACCUMULATIONS
LIKELY. THE SNOW COULD BECOME HEAVY AT TIMES AT CROSSVILLE WITH
VERTICAL VISIBILITIES OF < 100 FEET AND HORIZONTAL VISIBILITIES
DOWN TO 1/4 SM WITH SNOW ACCUMULATIONS LIKELY. SNOW WILL CONTINUE
INTO THE EVENING ALONG THE PLATEAU.
BOYD
PREV DISCUSSION... /ISSUED 354 PM CST WED JAN 16 2013/
DISCUSSION...LIGHT RAIN CONTINUES TO TRICKLE ACROSS MAINLY
SOUTHERN AND EASTERN MIDDLE TENNESSEE, WITH THE COLDEST PARTS OF
THE MID STATE STILL ECHO-FREE. LOOK FOR PRECIPITATION TO GRADUALLY
INCREASE OVERNIGHT AND TOMORROW AS AN UPPER LOW, CURRENTLY LOCATED
OVER THE ARK-LA-TEX, MOVES EASTWARD OVER THE NEXT 24 HOURS AND
SPREADS ADDITIONAL MOISTURE OVER MIDDLE TENNESSEE. WITH THE MID
STATE REMAINING ON THE COLD SIDE OF THE LOW, TEMPERATURES AREN`T
GOING TO WARM A GREAT DEAL. AREAS TO BE AFFECTED BY THIS SYSTEM
ARE PRIMARILY THE AREAS BEING AFFECTED NOW, THAT BEING SOUTHERN
MIDDLE TENNESSEE AND AREAS ALONG AND JUST WEST OF THE CUMBERLAND
PLATEAU. PRECIPITATION WILL REMAIN LIQUID DURING THE EVENING, BUT
LIGHT SNOW MAY MIX IN OVERNIGHT ACROSS THE COLDER PARTS, INCLUDING
THE NASHVILLE METRO AREA. LIGHT ACCUMULATIONS MAY OCCUR AS
TEMPERATURES BRIEFLY DROP TO FREEZING, BUT POP`S IN THESE AREAS
ARE LOW AND QPF`S REMAIN LOW, SO VERY LITTLE FROZEN PRECIPITATION
WILL OCCUR. LOOK FOR THE RAIN/SNOW MIX TO SPREAD EASTWARD DURING
THE MORNING AS ABOVE-SURFACE TEMPERATURES ALONG THE PLATEAU COOL.
(THICKNESS VALUES BY THURSDAY AFTERNOON DO SUPPORT SNOW.) SURFACE
TEMPERATURES WILL REMAIN ABOVE FREEZING THROUGHOUT MOST OF THE
DAY, WITH TEMPERATURES GETTING INTO THE LOWER 40`S TOMORROW
AFTERNOON ACROSS MAINLY THE WESTERN HALF OF MIDDLE TENNESSEE.
PLATEAU LOCATIONS WILL LIKELY SEE LIGHT ACCUMULATION OF SNOW
THURSDAY AFTERNOON AND EARLY EVENING, WITH AMOUNTS GENERALLY UNDER
ONE-HALF INCH. THIS WILL KEEP US BELOW ADVISORY CRITERIA, SO WILL
COVER THIS WITH A SPECIAL WEATHER STATEMENT SHORTLY.
&&
.OHX WATCHES/WARNINGS/ADVISORIES...
WINTER STORM WATCH FROM 6 AM CST THURSDAY THROUGH THURSDAY
AFTERNOON FOR TNZ011-032>034-065-066-077>080.
&&
$$
01
AREA FORECAST DISCUSSION
NWS ALBANY NY
910 AM EST THU JAN 17 2013
.SYNOPSIS...
AN ARCTIC COLD FRONT WILL CROSS THE REGION TODAY. THIS FRONT WILL
BRING SOME SNOW SHOWERS TO THE ADIRONDACKS FOR THIS
MORNING...FLURRIES ELSEWHERE. THEN...IT WILL TURN COLD AND BLUSTERY
TONIGHT AND TOMORROW. A WARM FRONT WILL ALLOW TEMPERATURES TO RETURN
ABOVE NORMAL AGAIN BRIEFLY FOR SATURDAY BEFORE ANOTHER STRONG COLD
FRONT RETURNS COLD WEATHER TO THE AREA FOR SUNDAY INTO EARLY NEXT
WEEK.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
AS OF 900 AM...SNOW SHOWERS OR FLURRIES HAVE EXPANDED WELL PAST THE
ADIRONDACKS PARK...INTO THE GREATER CAPITAL DISTRICT. THESE SNOW
SHOWERS/FLURRIES ARE WELL AHEAD OF AN ARCTIC FRONT...STILL NORTH OF
THE REGION...POISED TO COME DOWN DURING THE DAY...PROBABLY NOT
CLEARING OUR SOUTHERN AREAS UNTIL THIS EVENING.
MEANWHILE...TEMPERATURES HAVE ETCHED UPWARD AHEAD OF THE FRONT...SO
HAD TO MAKE ADJUSTMENTS ON HIGH TEMPS TODAY...ONLY BY A COUPLE OF
DEGREES. THINKING IS TEMPERATURES SHOULD LEVEL OFF LATER THIS
MORNING (EXCEPT MID HUDSON VALLEY AND LOWER LITCHFIELD) WHERE THEY
WILL RISE INTO THE AFTERNOON BEFORE FALLING.
SNOW SHOWERS SHOULD ONLY ADD MINOR ACCUMULATIONS...OF AROUND AN INCH
OR LESS IN SPOTS ACROSS THE ADIRONDACKS. LITTLE OR NO ACCUMULATIONS
EXPECTED ELSEWHERE.
THE ARCTIC BOUNDARY SHOULD CROSS THE ADIRONDACK REGION BY THE MID
MORNING HOURS. AS THIS BOUNDARY CONTINUES TO MOVE ACROSS THE
REGION...SNOW SHOWERS WILL BECOME MORE ISOLD. 00Z NAM12
GUIDANCE...AS WELL AS THE LOCAL HIRES WRF AND THE 3KM HRRR GUIDANCE
ALL SHOW THIS BAND OF SNOW SHOWERS FALLING APART AS IT REACHES THE
MOHAWK VALLEY/SARATOGA AREA/SRN VT/CAPITAL REGION AROUND NOON DUE TO
LITTLE MOISTURE AVAILABLE...SO WILL CONTINUE WITH ONLY GO WITH
SLIGHT CHC POPS OUTSIDE THE ADIRONDACKS. WHILE THERE MAY BE A FEW
FLURRIES FOR THESE VALLEY AREAS LATE THIS MORNING/EARLY THIS
AFTN...NO SNOW ACCUMULATION IS ANTICIPATED. THE FRONT WILL THEN
CONTINUE SOUTHEAST ACROSS THE CATSKILLS/MID HUDSON
VALLEY/BERKSHIRES/NW CT FOR THIS AFTN...BUT WITH NO PRECIP
ASSOCIATED WITH IT.
THE MAIN IMPACT WITH THIS FRONT WILL BE THE SHARP TEMPERATURE
GRADIENT. MAX TEMPS WILL OCCUR AHEAD OF THE FRONT...WITH TEMPS
RANGING FROM NEAR 20 IN THE ADIRONDACKS TO NEAR 40 IN THE MID
HUDSON VALLEY. ONCE THE FRONT MOVES THROUGH...TEMPS WILL RAPIDLY
FALL...ALONG WITH GUSTY W-NW WINDS. SOME WIND GUSTS...ESP IN AREAS
OF CHANNELED FLOW SUCH AS THE MOHAWK VALLEY/CAPITAL REGION...COULD
REACH UP TO 25 MPH. THIS WILL MAKE FOR A COLD AND BLUSTERY
AFTERNOON...ESP FROM THE CAPITAL REGION ON NORTH.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH SATURDAY NIGHT/...
IN THE WAKE OF THE FRONT...850 HPA TEMPS PLUNGE TO -16 TO -21
DEGREES C ACROSS THE REGION. THIS WILL RESULT IN VERY COLD
TEMPERATURES TONIGHT. AS WINDS BECOME LIGHT...THE EXISTING SNOW
PACK WILL AID IN ALLOWING FOR COLD MIN TEMPS...WITH SINGLE DIGITS
TO TEENS FOR AREAS FROM THE MOHAWK VALLEY/CAPITAL REGION
SOUTHWARD. NORTHERN AREAS LOOK TO BE VERY COLD...WITH READINGS
BELOW ZERO ACROSS THE ADIRONDACKS/LAKE GEORGE/GLENS FALLS AREA AND
GREEN MTNS OF SRN VT. SOME PORTIONS OF THE CENTRAL ADKS MAY DROP
-10 TO -20 DEGREES F. WIND SPEEDS SHOULD DROP TO 5 MPH OR LESS
DURING THE COLDEST PERIODS ACROSS THE ADIRONDACKS SO NO WIND CHILL
ADVISORIES WILL BE ISSUED. HOWEVER...THESE COLD AMBIENT TEMPS WILL
STILL BE HAZARDOUS ENOUGH TO CAUSE FROSTBITE QUICKLY...SO BE SURE
TO TAKE EXTREME CAUTION IF YOU PLAN ON BEING IN THE BACK COUNTRY
DURING THE OVERNIGHT HOURS. DESPITE THE COLD TEMPS...IT WON/T BE
COMPLETELY CLEAR TONIGHT DUE TO THE UPPER TROUGH PASSING OVERHEAD
AND SOME PASSING CLOUDS WILL BE AROUND. HOWEVER...NO SNOW SHOWERS
ARE EXPECTED...ALTHOUGH SOME ICE CRYSTALS /DIAMOND DUST/ ARE
POSSIBLE ACROSS THE ADIRONDACKS DUE TO THE COLD TEMPS.
ON FRIDAY...A FEW LAKE EFFECT FLURRIES ARE POSSIBLE FOR FAR
WESTERN AREAS...BUT THE SHEAR ISN/T FAVORABLE FOR MUCH LAKE EFFECT
TO OCCUR. LITTLE TO NO SNOW ACCUMULATION IS EXPECTED FOR OUR
AREA. OTHERWISE...IT LOOKS TO REMAIN DRY WITH PARTLY TO MOSTLY
SUNNY SKIES. WARM AIR ADVECTION WILL BEGIN TO TAKE PLACE BY LATE
IN THE DAY AS A WARM FRONT STARTS TO MOVE NORTH FROM THE SOUTH.
MAX TEMPS ON FRIDAY WILL BE COLD WITH TEENS AND 20S ACROSS THE
AREA.
SOUTHERLY WINDS...AND WARMING TEMPS ALOFT...WILL ALLOW FOR FRI
NIGHT TO NOT BE AS COLD AS TONIGHT. IT WILL ONLY DROP A FEW
DEGREES FROM FRIDAY/S HIGHS ACROSS THE AREA...AND TEMPS MAY EVEN
HOLD STEADY OR RISE AT TIMES.
BY SATURDAY...THE REGION WILL BE BACK IN A WARM SECTOR...AND
ABOVE NORMAL TEMPS WILL RETURN...WITH 30S TO LOW 40S ACROSS THE
REGION. A CLIPPER SYSTEM WILL PASS ACROSS SOUTHERN CANADA...AND IT
MAY BE CLOSE ENOUGH TO BRING SOME LIGHT SNOW TO THE
ADIRONDACKS...ALTHOUGH THE BEST ACTIVITY LOOKS TO STAY NORTH OF
THE US/CANADIAN BORDER. OTHERWISE...SKIES WILL BE PARTLY TO MOSTLY
CLOUDY.
ANOTHER ARCTIC FRONT WILL START TO APPROACH THE AREA FOR SATURDAY
NIGHT. THE REGION SHOULD REMAIN OUT AHEAD OF IT THROUGH THE
OVERNIGHT HOURS...SO TEMPS SAT NIGHT WON/T BE COLD YET /MAINLY
20S/. SOME SNOW SHOWERS MAY AFFECT MAINLY WESTERN PARTS OF THE
REGION...ESP FOR THE LATE NIGHT HOURS.
&&
.LONG TERM /SUNDAY THROUGH WEDNESDAY/...
LOOKING AT A PERIOD OF BELOW NORMAL TEMPERATURES...
NORMAL TEMPERATURES FOR THE PERIOD JAN 20TH THROUGH 23RD:
ALBANY: HIGHS AROUND 30. LOWS IN THE MID TEENS.
GLENS FALLS: HIGHS IN THE UPPER 20S. LOWS IN THE SINGLE DIGITS.
POUGHKEEPSIE: HIGHS IN THE MID 30S. LOWS IN THE MID TEENS.
BENNINGTON: HIGHS AROUND 30. LOWS NEAR 10.
PITTSFIELD: HIGHS IN THE UPPER 20S. LOWS NEAR 10.
MODEL GUIDANCE IS IN AGREEMENT IN REGARDS TO THE LONGWAVE PATTERN
FOR THE PERIOD WITH A LARGE TROUGH COVERING THE EASTERN 2/3 OF THE
CONUS WITH SHORT WAVES ROTATING ABOUT AN UPPER LOW OVER HUDSON BAY
CANADA AND RIDGING ALONG THE WEST COAST. THE DIFFERENCES IN THE
MODELS ARE WITH THE TIMING OF THE SHORT WAVES AND ASSOCIATED FRONTAL
BOUNDARIES CROSSING THE REGION.
AN ARCTIC FRONT WILL CROSS THE REGION SUNDAY. THIS FRONT WILL HAVE
SOME DECENT UPPER LEVEL DYNAMICS AND A SHARP THERMAL GRADIENT
ASSOCIATED WITH IT...SO A ROUND OF SNOW SHOWERS/SQUALLS IS POSSIBLE
WITH THE FRONTAL PASSAGE. WINDS WILL SHIFT WEST-NORTHWEST AND BECOME
BRISK AND GUSTY IN ITS WAKE AND TEMPERATURES SHOULD DROP DURING THE
AFTERNOON.
IT WILL GET COLD SUNDAY NIGHT WITH 850 MB TEMPERATURES DROPPING TO
-15 TO -20 C ACROSS THE FORECAST AREA. WESTERLY WINDS OF 10 TO 20
MPH WILL MAKE IT FEEL EVEN COLDER. WIND CHILL VALUES MAY REACH
ADVISORY CRITERIA (-20F) ACROSS THE SOUTHERN ADIRONDACKS...HAVE
MENTION IN OUR HAZARDOUS WEATHER OUTLOOK.
SHORT WAVES ROTATING ABOUT THE UPPER LOW WILL BRING REINFORCING
SHOTS OF COLDER AIR TO THE REGION AS CLIPPER SYSTEMS MOVE THROUGH.
THIS WILL KEEP CLOUDS AND THE THREAT OF SNOW SHOWERS IN THE
FORECAST. THE SYSTEMS WILL HAVE LIMITED MOISTURE ASSOCIATED WITH
THEM SO ANY PRECIPITATION/SNOW SHOULD BE LIGHT.
HIGHS AND LOWS MONDAY THROUGH WEDNESDAY WILL BE SIMILAR EACH DAY AND
NIGHT RUNNING AROUND 5 TO 10 DEGREES BELOW NORMAL. THE DIFFERENCE
WILL BE THE WINDS AND HOW COLD IT FEELS. WIND CHILL COULD BE AN
ISSUE AGAIN MONDAY NIGHT INTO TUESDAY MORNING ACROSS THE SOUTHERN
ADIRONDACKS...HAVE MENTION IN OUR HAZARDOUS WEATHER OUTLOOK.
&&
.AVIATION /14Z THURSDAY THROUGH MONDAY/...
LOW STRATUS CLOUDS FINALLY BROKE UP AT KGFL. VFR CONDITIONS ARE NOW
EXPECTED THROUGH 12Z/FRIDAY. ARCTIC COLD FRONT MOVING INTO NEW YORK
STATE...ON THE DOOR STEP TO THE FORECAST AREA. BOUNDARY WILL MOVE
ACROSS THE AREA TODAY. SOUTH TO SOUTHWEST WINDS WILL SHIFT TO THE
WEST WITH THE FRONTAL PASSAGE AND INCREASE IN SPEED WITH GUSTY
CONDITIONS AT KALB AND KPSF. WINDS WILL SHIFT MORE TO THE NORTHWEST
AND NORTH THIS EVENING AND WEAKEN.
OUTLOOK...
FRI-SAT...VFR...NO SIG WX.
SUN...MAINLY VFR. CHC -SHSN.
MON...VFR. SLIGHT CHC -SHSN.
&&
.HYDROLOGY...
MAINLY DRY AND COLD WEATHER WILL OCCUR OVER THE NEXT FIVE DAYS.
WHILE SOME SNOW SHOWERS ARE POSSIBLE OVER THE NEXT FEW DAYS ACROSS
NORTHERN AREAS...PRECIPITATION AMOUNTS WILL BE LIGHT AND IN THE
FORM OF SNOW. COLD TEMPERATURES...ESPECIALLY EARLY NEXT
WEEK...WILL CAUSE RIVER AND LAKE ICE TO FORM AND THICKEN.
FOR DETAILS ON SPECIFIC AREA RIVERS AND LAKES...INCLUDING
OBSERVED AND FORECAST RIVER STAGES AND LAKE ELEVATIONS...PLEASE
VISIT THE ADVANCED HYDROLOGIC PREDICTION SERVICE /AHPS/ GRAPHS ON
OUR WEBSITE.
&&
.ALY WATCHES/WARNINGS/ADVISORIES...
CT...NONE.
NY...NONE.
MA...NONE.
VT...NONE.
&&
$$
SYNOPSIS...FRUGIS/HWJIV
NEAR TERM...FRUGIS/HWJIV
SHORT TERM...FRUGIS
LONG TERM...IAA
AVIATION...IAA
HYDROLOGY...FRUGIS
AREA FORECAST DISCUSSION
NWS ALBANY NY
638 AM EST THU JAN 17 2013
.SYNOPSIS...
AN ARCTIC COLD FRONT WILL CROSS THE REGION TODAY. THIS
FRONT WILL BRING SOME SNOW SHOWERS TO THE ADIRONDACKS FOR THIS
MORNING AS WELL AS ALLOWING MUCH COLDER AND BLUSTERY WEATHER INTO
THE REGION FOR TONIGHT AND TOMORROW. A WARM FRONT WILL ALLOW
TEMPERATURES TO RETURN ABOVE NORMAL AGAIN BRIEFLY FOR SATURDAY
BEFORE ANOTHER STRONG COLD FRONT RETURNS COLD WEATHER TO THE AREA
FOR SUNDAY INTO EARLY NEXT WEEK.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
AS OF 638 AM EST...SATELLITE AND SURFACE OBS SHOW AN ARCTIC COLD
FRONT CROSSING NORTHERN AND WESTERN NEW YORK. AHEAD OF THIS
BOUNDARY...THE COMBINATION OF SOME LAKE MOISTURE...LARGE SCALE
LIFT FROM THE COLD FRONT AND UPSLOPE FLOW IS ALLOWING FOR SOME
SNOW SHOWERS ACROSS THE WESTERN ADIRONDACKS...MAINLY ACROSS
NORTHERN HERKIMER COUNTY. LIGHT SNOW ACCUMULATION OF AN INCH OR
LESS IS POSSIBLE ACROSS THE WESTERN ADIRONDACKS. THE BOUNDARY
SHOULD CROSS THE ADIRONDACK REGION BY THE MID MORNING HOURS. AS
THIS BOUNDARY CONTINUES TO MOVE ACROSS THE REGION...SNOW SHOWERS
WILL BECOME MORE ISOLD. 00Z NAM12 GUIDANCE...AS WELL AS THE LOCAL
HIRES WRF AND THE 3KM HRRR GUIDANCE ALL SHOW THIS BAND OF SNOW
SHOWERS FALLING APART AS IT REACHES THE MOHAWK VALLEY/SARATOGA
AREA/SRN VT/CAPITAL REGION AROUND NOON DUE TO LITTLE MOISTURE
AVAILABLE...SO WILL ONLY GO WITH SLIGHT CHC POPS OUTSIDE THE
ADIRONDACKS. WHILE THERE MAY BE A FEW FLURRIES FOR THESE VALLEY
AREAS LATE THIS MORNING/EARLY THIS AFTN...NO SNOW ACCUMULATION IS
ANTICIPATED. THE FRONT WILL THEN CONTINUE SOUTHEAST ACROSS THE
CATSKILLS/MID HUDSON VALLEY/BERKSHIRES/NW CT FOR THIS AFTN...BUT
WITH NO PRECIP ASSOCIATED WITH IT.
THE MAIN IMPACT WITH THIS FRONT WILL BE THE SHARP TEMPERATURE
GRADIENT. MAX TEMPS WILL OCCUR AHEAD OF THE FRONT...WITH TEMPS
RANGING FROM NEAR 20 IN THE ADIRONDACKS TO NEAR 40 IN THE MID
HUDSON VALLEY. ONCE THE FRONT MOVES THROUGH...TEMPS WILL RAPIDLY
FALL...ALONG WITH GUSTY W-NW WINDS. SOME WIND GUSTS...ESP IN AREAS
OF CHANNELED FLOW SUCH AS THE MOHAWK VALLEY/CAPITAL REGION...COULD
REACH UP TO 25 MPH. THIS WILL MAKE FOR A COLD AND BLUSTERY
AFTERNOON...ESP FROM THE CAPITAL REGION ON NORTH.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH SATURDAY NIGHT/...
IN THE WAKE OF THE FRONT...850 HPA TEMPS PLUNGE TO -16 TO -21
DEGREES C ACROSS THE REGION. THIS WILL RESULT IN VERY COLD
TEMPERATURES TONIGHT. AS WINDS BECOME LIGHT...THE EXISTING SNOW
PACK WILL AID IN ALLOWING FOR COLD MIN TEMPS...WITH SINGLE DIGITS
TO TEENS FOR AREAS FROM THE MOHAWK VALLEY/CAPITAL REGION
SOUTHWARD. NORTHERN AREAS LOOK TO BE VERY COLD...WITH READINGS
BELOW ZERO ACROSS THE ADIRONDACKS/LAKE GEORGE/GLENS FALLS AREA AND
GREEN MTNS OF SRN VT. SOME PORTIONS OF THE CENTRAL ADKS MAY DROP
-10 TO -20 DEGREES F. WIND SPEEDS SHOULD DROP TO 5 MPH OR LESS
DURING THE COLDEST PERIODS ACROSS THE ADIRONDACKS SO NO WIND CHILL
ADVISORIES WILL BE ISSUED. HOWEVER...THESE COLD AMBIENT TEMPS WILL
STILL BE HAZARDOUS ENOUGH TO CAUSE FROSTBITE QUICKLY...SO BE SURE
TO TAKE EXTREME CAUTION IF YOU PLAN ON BEING IN THE BACK COUNTRY
DURING THE OVERNIGHT HOURS. DESPITE THE COLD TEMPS...IT WON/T BE
COMPLETELY CLEAR TONIGHT DUE TO THE UPPER TROUGH PASSING OVERHEAD
AND SOME PASSING CLOUDS WILL BE AROUND. HOWEVER...NO SNOW SHOWERS
ARE EXPECTED...ALTHOUGH SOME ICE CRYSTALS /DIAMOND DUST/ ARE
POSSIBLE ACROSS THE ADIRONDACKS DUE TO THE COLD TEMPS.
ON FRIDAY...A FEW LAKE EFFECT FLURRIES ARE POSSIBLE FOR FAR
WESTERN AREAS...BUT THE SHEAR ISN/T FAVORABLE FOR MUCH LAKE EFFECT
TO OCCUR. LITTLE TO NO SNOW ACCUMULATION IS EXPECTED FOR OUR
AREA. OTHERWISE...IT LOOKS TO REMAIN DRY WITH PARTLY TO MOSTLY
SUNNY SKIES. WARM AIR ADVECTION WILL BEGIN TO TAKE PLACE BY LATE
IN THE DAY AS A WARM FRONT STARTS TO MOVE NORTH FROM THE SOUTH.
MAX TEMPS ON FRIDAY WILL BE COLD WITH TEENS AND 20S ACROSS THE
AREA.
SOUTHERLY WINDS...AND WARMING TEMPS ALOFT...WILL ALLOW FOR FRI
NIGHT TO NOT BE AS COLD AS TONIGHT. IT WILL ONLY DROP A FEW
DEGREES FROM FRIDAY/S HIGHS ACROSS THE AREA...AND TEMPS MAY EVEN
HOLD STEADY OR RISE AT TIMES.
BY SATURDAY...THE REGION WILL BE BACK IN A WARM SECTOR...AND
ABOVE NORMAL TEMPS WILL RETURN...WITH 30S TO LOW 40S ACROSS THE
REGION. A CLIPPER SYSTEM WILL PASS ACROSS SOUTHERN CANADA...AND IT
MAY BE CLOSE ENOUGH TO BRING SOME LIGHT SNOW TO THE
ADIRONDACKS...ALTHOUGH THE BEST ACTIVITY LOOKS TO STAY NORTH OF
THE US/CANADIAN BORDER. OTHERWISE...SKIES WILL BE PARTLY TO MOSTLY
CLOUDY.
ANOTHER ARCTIC FRONT WILL START TO APPROACH THE AREA FOR SATURDAY
NIGHT. THE REGION SHOULD REMAIN OUT AHEAD OF IT THROUGH THE
OVERNIGHT HOURS...SO TEMPS SAT NIGHT WON/T BE COLD YET /MAINLY
20S/. SOME SNOW SHOWERS MAY AFFECT MAINLY WESTERN PARTS OF THE
REGION...ESP FOR THE LATE NIGHT HOURS.
&&
.LONG TERM /SUNDAY THROUGH WEDNESDAY/...
...LOOKING AT A PERIOD OF BELOW NORMAL TEMPERATURES...
NORMAL TEMPERATURES FOR THE PERIOD JAN 20TH THROUGH 23RD:
ALBANY: HIGHS AROUND 30. LOWS IN THE MID TEENS.
GLENS FALLS: HIGHS IN THE UPPER 20S. LOWS IN THE SINGLE DIGITS.
POUGHKEEPSIE: HIGHS IN THE MID 30S. LOWS IN THE MID TEENS.
BENNINGTON: HIGHS AROUND 30. LOWS NEAR 10.
PITTSFIELD: HIGHS IN THE UPPER 20S. LOWS NEAR 10.
MODEL GUIDANCE IS IN AGREEMENT IN REGARDS TO THE LONGWAVE PATTERN
FOR THE PERIOD WITH A LARGE TROUGH COVERING THE EASTERN 2/3 OF THE
CONUS WITH SHORT WAVES ROTATING ABOUT AN UPPER LOW OVER HUDSONS BAY
CANADA AND RIDGING ALONG THE WEST COAST. THE DIFFERENCES IN THE
MODELS ARE WITH THE TIMING OF THE SHORT WAVES AND ASSOCIATED FRONTAL
BOUNDARIES CROSSING THE REGION.
AN ARCTIC FRONT WILL CROSS THE REGION SUNDAY. THIS FRONT WILL HAVE
SOME DECENT UPPER LEVEL DYNAMICS AND A SHARP THERMAL GRADIENT
ASSOCIATED WITH IT...SO A ROUND OF SNOW SHOWERS/SQUALLS IS POSSIBLE
WITH THE FRONTAL PASSAGE. WINDS WILL SHIFT WEST-NORTHWEST AND BECOME
BRISK AND GUSTY IN ITS WAKE AND TEMPERATURES SHOULD DROP DURING THE
AFTERNOON.
IT WILL GET COLD SUNDAY NIGHT WITH 850 MB TEMPERATURES DROPPING TO
-15 TO -20 C ACROSS THE FORECAST AREA. WESTERLY WINDS OF 10 TO 20
MPH WILL MAKE IT FEEL EVEN COLDER. WIND CHILL VALUES MAY REACH
ADVISORY CRITERIA (-20F) ACROSS THE SOUTHERN ADIRONDACKS...HAVE
MENTION IN OUR HAZARDOUS WEATHER OUTLOOK.
SHORT WAVES ROTATING ABOUT THE UPPER LOW WILL BRING REINFORCING
SHOTS OF COLDER AIR TO THE REGION AS CLIPPER SYSTEMS MOVE THROUGH.
THIS WILL KEEP CLOUDS AND THE THREAT OF SNOW SHOWERS IN THE
FORECAST. THE SYSTEMS WILL HAVE LIMITED MOISTURE ASSOCIATED WITH
THEM SO ANY PRECIPITATION/SNOW SHOULD BE LIGHT.
HIGHS AND LOWS MONDAY THROUGH WEDNESDAY WILL BE SIMILAR EACH DAY AND
NIGHT RUNNING AROUND 5 TO 10 DEGREES BELOW NORMAL. THE DIFFERENCE
WILL BE THE WINDS AND HOW COLD IT FEELS. WIND CHILL COULD BE AN
ISSUE AGAIN MONDAY NIGHT INTO TUESDAY MORNING ACROSS THE SOUTHERN
ADIRONDACKS...HAVE MENTION IN OUR HAZARDOUS WEATHER OUTLOOK.
&&
.AVIATION /12Z THURSDAY THROUGH MONDAY/...
LOW STRATUS CLOUDS FINALLY BROKE UP AT KGFL. VFR CONDITIONS ARE NOW
EXPECTED THROUGH 12Z/FRIDAY. ARCTIC COLD FRONT MOVING INTO NEW YORK
STATE...ON THE DOOR STEP TO THE FORECAST AREA. BOUNDARY WILL MOVE
ACROSS THE AREA TODAY. SOUTH TO SOUTHWEST WINDS WILL SHIFT TO THE
WEST WITH THE FRONTAL PASSAGE AND INCREASE IN SPEED WITH GUSTY
CONDITIONS AT KALB AND KPSF. WINDS WILL SHIFT MORE TO THE NORTHWEST
AND NORTH THIS EVENING AND WEAKEN.
OUTLOOK...
FRI-SAT...VFR...NO SIG WX.
SUN...MAINLY VFR. CHC -SHSN.
MON...VFR. SLIGHT CHC -SHSN.
&&
.HYDROLOGY...
MAINLY DRY AND COLD WEATHER WILL OCCUR OVER THE NEXT FIVE DAYS.
WHILE SOME SNOW SHOWERS ARE POSSIBLE OVER THE NEXT FEW DAYS ACROSS
NORTHERN AREAS...PRECIPITATION AMOUNTS WILL BE LIGHT AND IN THE
FORM OF SNOW. COLD TEMPERATURES...ESPECIALLY EARLY NEXT
WEEK...WILL CAUSE RIVER AND LAKE ICE TO FORM AND THICKEN.
FOR DETAILS ON SPECIFIC AREA RIVERS AND LAKES...INCLUDING
OBSERVED AND FORECAST RIVER STAGES AND LAKE ELEVATIONS...PLEASE
VISIT THE ADVANCED HYDROLOGIC PREDICTION SERVICE /AHPS/ GRAPHS ON
OUR WEBSITE.
&&
.ALY WATCHES/WARNINGS/ADVISORIES...
CT...NONE.
NY...NONE.
MA...NONE.
VT...NONE.
&&
$$
SYNOPSIS...FRUGIS
NEAR TERM...FRUGIS
SHORT TERM...FRUGIS
LONG TERM...IAA
AVIATION...IAA
HYDROLOGY...FRUGIS
AREA FORECAST DISCUSSION
NWS CARIBOU ME
509 AM EST THU JAN 17 2013
.SYNOPSIS...
LOW PRESSURE WILL QUICKLY TO THE EAST LATE TONIGHT. A STRONG
ARCTIC COLD FRONT WILL CROSS THE STATE THURSDAY. HIGH PRESSURE
WILL BUILD EAST FRIDAY...WHILE LOW PRESSURE TRACKS SOUTH OF THE
GULF OF MAINE. LOW PRESSURE WILL TRACK TOWARDS THE REGION ON SUNDAY.
&&
.NEAR TERM /THROUGH TONIGHT/...
MOST OF THE FA IS NOW IN A BREAK BETWEEN SN SHWR ACTION TO OUR E
AND NEW SN SHWRS ADVCG EWRD INTO THE REGION FROM QB. IN ADDITION...
A SN SQUALL IS CURRENTLY APCHG THE ST LAWRENCE RVR VLY OF ERN QB
WITH SEVERAL OBS INDICATING WIND GUSTS TO 40 TO 45 MPH AND NEAR
WHITEOUT CONDITIONS OCCURRING WITH THE SQUALL. HRRR GUIDANCE
INDICATES THAT SOME PORTION OF THIS LN OF SN SHWRS WILL GET INTO
OUR FA THIS MORN...BUT NOT SURE HOW INTENSE THE LN WILL CONTINUE
AS IT MOVES TOWARD NB. WE DID GO WITH LIKELY POPS FOR NRN AREAS
AND CHC POPS SRN AREAS...HIGHLIGHTING AN HRLY PROGRESSION ACROSS
THE REGION FROM 12-16Z. IF WORSE COMES TO WORSE...WE CAN ISSUE A
BLOWING SN ADV TO HIGHLIGHT THE PRESENCE OF THIS SN SQUALL AS IT
MOVES E THRU SPCLY NRN PTNS OF THE FA WHERE POWDERY SN FELL LAST
NGT.
BEHIND THE FRONT...TEMPS DROP UP TO 10 TO 15 DEG F WITHIN AN
HR...AND THEN CONT TO FALL OFF GRADUALLY THRU THE REMAINDER OF THE
AFT WITH BRISK N TO NW WINDS OF 15 TO 25 MPH. THE COMBO OF
LOWERING TEMPS AND WINDS HAS WARRANTED A WIND CHILL ADV FOR
NW AND FAR NERN ME BEGINNING LATE THIS AFTN AND CONTG THRU THE
EVE. WITH WINDS DIMINISHING BLO 5 MPH BY MDNGT OVR NRN PTNS OF THE
FA AS A RIDGE OF HI PRESS SETTLES OVR THE REGION...WE BELIEVE THE
WIND CHILL ADV FOR THE NW AND FAR NE WILL NO LONGER BE NEEDED AFT
MDNGT. E CNTRL AND SPCLY DOWNEAST AREAS WILL BE NEAR THE -20 DEG
WIND CHILL CRITERIA LATER TNGT INTO FRI MORN AS WINDS REMAIN A
LITTLE STRONGER DUE TO BEING IN THE FAR NRN PTN OF THE GRADIENT
ASSOCIATED WITH LOW PRESSURE MOVG NE IN THE OPEN ATLC...SO WE
CANNOT RULE OUT THE POSSIBILITY OF ANOTHER WIND CHILL ADV MAY NEED
TO BE ISSUED OVR THIS PTN OF THE FA BY THE AFTN FCST UPDATE.
LASTLY...WITH MCLR SKIES AND SLACKENING EVE WINDS...ARCTIC INVSN
CONDITIONS ARE A GOOD BET FOR OUR NW VLYS LATE TNGT...BRINGING THE
COLDEST LOW TEMPS...OF THE SEASON SO FAR...PERHAPS AS LOW 30 BELOW
ZERO FOR COLDEST LOCATIONS.
&&
.SHORT TERM /FRIDAY THROUGH SATURDAY/...
HIGH PRESSURE DOMINATES FRIDAY WITH BITTERLY COLD TEMPERATURES.
HIGHS WILL BE IN THE ZERO TO FIVE BELOW RANGE NORTH OF HOULTON AND
SINGLE DIGITS FOR BANGOR AND DOWN EAST. COASTAL LOCATIONS MAY JUST
EDGE INTO THE LOW TEENS. WITH WINDS OVER 10 MPH BY MID TO LATE
MORNING...EXPECT A STRONG POSSIBILITY OF A WIND CHILL ADVISORY.
WIND CHILLS WILL BE -20F TO -30F ALL DAY NORTH OF HOULTON AND
NEAR -20F AROUND BANGOR IN THE MORNING. TEMPERATURES WILL FALL
QUICKLY FRIDAY EVENING TOWARDS MINUS 10F IN THE CROWN OF MAINE AND
TOWARDS ZERO FOR DOWN EAST. HOWEVER...A FAST-MOVING CLIPPER SYSTEM
WILL ARRIVE AFTER MIDNIGHT WITH THICKENING CLOUDS. THUS LOWS WILL
OCCUR NEAR MIDNIGHT AND TEMPERATURES WILL RISE AFTER WARDS. THIS
CLIPPER WILL PRODUCE LIGHT OVERRUNNING SNOW LATE FRIDAY NIGHT
THROUGH THE DAY SATURDAY. ANTICIPATE AMOUNTS IN THE ONE TO TWO
INCH RANGE IN NORTHERN ZONES...BUT LESS THAN AN INCH DOWN EAST.
SOUTHERLY WINDS WILL ALLOW TEMPERATURES TO RISE FROM LATE FRIDAY
NIGHT THROUGH THE DAY ON SATURDAY...REACHING THE LOW TO MID 30S
ALONG THE COAST AND LOW 20S IN NORTHERN AROOSTOOK COUNTY.
&&
.LONG TERM /SATURDAY NIGHT THROUGH WEDNESDAY/...
A LOW PRESSURE SYSTEM WILL INTENSIFY IN THE NORTHERN GREAT LAKES
REGION LATE SATURDAY THROUGH SUNDAY MORNING WITH A WARM FRONT
EXTENDING EAST INTO NORTHERN MAINE. THE OVERRUNNING SNOW IS
EXPECTED TO CONTINUE SATURDAY NIGHT AND INCREASE AFTER MIDNIGHT AS
THE LOW MOVES INTO QUEBEC. TEMPERATURES WILL NOT FALL MUCH WITH
THE CONTINUING WARM AIR ADVECTION. SOME RAIN MAY MIX WITH THE SNOW
IN ZONES 29 AND 30 ALONG THE COAST. THE LATEST NWP GUIDANCE IS
SHOWING THE LOW TRACKING FURTHER TO THE NORTH DURING SUNDAY...WITH
THE MOST LIKELY TRACK JUST NORTH OF THE SJV. THE RESULT WILL BE AN
ADDITIONAL SEVERAL INCHES OF SNOW IN THE CROWN OF MAINE...BUT
LITTLE IF ANY ACCUMULATION DOWN EAST. HIGHS ON SUNDAY WILL REACH
THE MID TO UPPER 20S NORTH OF HOULTON AND LOW TO MID 30S SOUTH OF
HOULTON. THE COLD FRONT FOLLOWING THIS LOW WILL USHER IN ANOTHER
ROUND OF BITTERLY COLD TEMPERATURES. TEMPERATURES WILL PLUMMET TO
5 TO 10 BELOW ZERO IN NORTHERN ZONES SUNDAY NIGHT WHILE SINGLE
DIGITS ARE EXPECTED FOR BANGOR AND VICINITY. HIGHS WILL STRUGGLE
TO REACH ZERO FOR NORTHERN ZONES MONDAY THROUGH THURSDAY. LOWS
WILL BE WELL BELOW ZERO. THE BIG QUESTION WILL BE WHETHER WINDS
AND CLOUDS ALLOW DECOUPLING OF THE BOUNDARY LAYER AND PRODUCE
READINGS AS LOW AS 30 BELOW. THE FIRST CHANCE AT THIS WRITING
APPEARS TO BE MONDAY NIGHT. WILL GO FOR MINUS 10 AROUND BANGOR AND
LESS THAN MINUS 20 NORTH OF HOULTON ON MONDAY NIGHT. WITH THIS
COLD AIR IN PLACE...STORM SYSTEMS ARE EXPECTED TO PASS TO OUR
SOUTH FOR MONDAY INTO THURSDAY.
&&
.AVIATION /08Z THURSDAY THROUGH MONDAY/...
NEAR TERM: IFR AND MVFR CONDITIONS WILL IMPROVE TO VFR BY THIS
AFTN ACROSS DOWNEAST SITES BEHIND AN ARCTIC FRONT AND BY LATE
AFTN OVR NRN TAF SITES AFT A PD OF BLOWING AND DRIFTING SNOW
BEHIND THE ARCTIC FRONT. BRIEF WHITEOUT CONDITIONS MAY OCCUR AT
NRN TAF SITES WITH SN SQL ACTIVITY WITH THE COLD FRONT. ALL SITES
WILL THEN REMAIN VFR TNGT.
SHORT TERM: VFR FRIDAY INTO FRIDAY EVENING. BECOMING MVFR LATE
FRIDAY NIGHT THROUGH SATURDAY NIGHT. FROM HUL NORTHWARD...EXPECT
IFR LATER SATURDAY NIGHT THROUGH SUNDAY WHILE TERMINALS SOUTH OF
HUL WILL REMAIN MVFR SUNDAY. ALL AREAS WILL BE VFR MONDAY.
&&
.MARINE...
NEAR TERM: WILL CONT WITH AN SCA FOR WINDS BEHIND A DEPARTING LOW
PRES SYSTEM IN THE MARITIMES AND ALSO BEHIND ARCTIC COLD FRONT
XPCTD TO CROSS THE WATERS THIS AFTN. IN ADDITION TO SCA WINDS AND
SEAS...COLDER AIR WILL CREATE THE POTENTIAL OF MDT FZG SPY LATE
TNGT AFT MDNGT. WW3 WV HTS WERE ABOUT 2 FT TO LOW COMPARED TO
OBSVD BUOY WV HTS ERLY THIS MORN...SO WE BLENDED SWAN GFS
GUIDANCE AND ADDED ANOTHER FOOT TO IT FOR THIS MORN...THEN BLENDED
CLOSER TO WW3 GUIDANCE FOR TNGT.
SHORT TERM: AN SCA WILL CONTINUE FRIDAY. THERE MAY BE A BIT OF
RESPITE LATE FRIDAY AFTERNOON UNTIL AFTER MIDNIGHT FRIDAY NIGHT
BEFORE SCA CONDITIONS RETURN. GALE CONDITIONS ARE POSSIBLE DURING
SATURDAY AND AGAIN DURING SUNDAY WITH WIND GUSTS OVER 40 KTS
POSSIBLE...ESPECIALLY ON SUNDAY.
&&
.CAR WATCHES/WARNINGS/ADVISORIES...
ME...WIND CHILL ADVISORY FROM 4 PM THIS AFTERNOON TO MIDNIGHT EST
TONIGHT FOR MEZ001>004-010.
MARINE...SMALL CRAFT ADVISORY UNTIL 7 PM EST FRIDAY FOR ANZ050>052.
&&
$$
NEAR TERM...VJN
SHORT TERM...MCW
LONG TERM...MCW
AVIATION...VJN
MARINE...VJN/MCW
AREA FORECAST DISCUSSION
NWS DULUTH MN
554 AM CST THU JAN 17 2013
.AVIATION...12Z TAFS
CEILINGS FROM 3500-5000FEET COVERED MUCH OF THE NORTHLAND THIS
MORNING...WITH MVFR CEILINGS AND LIGHT SNOW MOVING TOWARD KBRD.
THESE LOWER CEILINGS ARE FORECAST BY THE RAP TO AFFECT
KHIB/KDLH/KHYR LATER TODAY...AND WE PUT THEM IN THE LATEST TAF.
CLOUDS WILL DIMINISH LATER THIS AFTERNOON/EARLY EVENING...BEFORE
INCREASING AGAIN OVERNIGHT IN AN AREA OF WAA. SOME LIGHT SNOW MAY
ALSO DEVELOP LATE TONIGHT.
&&
.PREV DISCUSSION... /ISSUED 410 AM CST THU JAN 17 2013/
SHORT TERM...TODAY THROUGH FRIDAY.
AT 4 AM...CLOUDS WERE ON THE INCREASE ACROSS THE CWA. THE RESULT
WAS A BIT OF IMPROVEMENT IN TEMPS AND WIND CHILL READINGS. HAVE
REMOVED ITASCA COUNTY...AND THE DULUTH AND SUPERIOR AREAS FROM THE
WIND CHILL ADVISORY...AS WIND CHILL READINGS HAD IMPROVED A BIT.
WILL LIKELY BE ABLE TO REMOVE OTHER COUNTIES AS THE MORNING WEARS
ON DUE TO THE INCREASING CLOUDS.
THE MAIN FOCUS FOR TODAY WILL BE THE WIND CHILL READINGS THIS
MORNING...ALONG WITH CLOUD TRENDS. THERE WILL LIKELY BE SOME
DECREASE IN CLOUDS ACROSS THE CWA TODAY. THE NAM ACTUALLY PICKS UP
ON THE BAND OF CLOUDS MOVING INTO NORTHERN MN...AND IT CARRIES
THAT SHORTWAVE TO THE EAST AS THE DAY WEARS ON. HIGH TEMPS WILL
LIKELY REMAIN A BIT BELOW ZERO IN THE FAR NORTH TODAY...BUT WILL
APPROACH 10 ABOVE IN THE SOUTH.
THE MAIN FOCUS FOR TONIGHT AND FRIDAY IS THE DEVELOPING LOW
PRESSURE SYSTEM THAT IS EXPECTED TO SLIDE INTO THE LAKE SUPERIOR
REGION THROUGH THE END OF THE WEEK. HAVE INCREASED POPS
CONSIDERABLY LATER TONIGHT AND INTO FRIDAY. COULD SEE SOME 2 TO 4
INCH AMOUNTS IN THE NORTH...AND POSSIBLY EVEN 3 TO 5 ACROSS THE
ARROWHEAD. WILL ALSO NEED TO WATCH THE NORTH SHORE FOR THE
POSSIBILITY OF LOCALIZED HIGHER AMOUNTS DUE TO LAKE ENHANCEMENT.
MAY NEED TO ISSUE ADVISORIES FOR PORTIONS OF THE NORTHLAND IN
LATER FORECAST PACKAGES. TEMPERATURES WILL WARM CONSIDERABLY ON
FRIDAY...ESPECIALLY ACROSS THE SOUTH...AS THE SOUTHERN HALF OF THE
CWA SHOULD BE IN THE WARM SECTOR DURING THE DAY.
LONG TERM...FRIDAY NIGHT THROUGH WEDNESDAY.
MUCH COLDER TEMPERATURES WILL BE MOVING INTO THE NORTHLAND IN THE
EXTENDED PERIOD.
A COUPLE SHORTWAVES WILL AFFECT THE NORTHLAND FRIDAY NIGHT INTO
SATURDAY...WITH THE STRONGER WAVE/LOW OCCURRING SATURDAY. LIGHT SNOW
WILL OCCUR FRIDAY NIGHT...MAINLY NORTH WITH OVERNIGHT ACCUMULATIONS
MAINLY RANGING FROM A DUSTING TO PERHAPS AN INCH. THE STRONGER WAVE
ON SATURDAY WILL BE ACCOMPANIED BY A DEEPENING LOW AND AS THEY
PASS...MUCH COLDER AIR WILL POUR INTO THE REGION. SOME ADDITIONAL
SNOWFALL WILL OCCUR SATURDAY...AGAIN MAINLY NORTH AND AMOUNTS WILL
BE SOMEWHAT LIMITED FOR MOST AREAS. A FEW INCHES WILL BE POSSIBLE
OVER THE ARROWHEAD. WE INCREASED TEMPS FRIDAY NIGHT INTO
SATURDAY...BEFORE THE COLD AIR MOVES IN. TEMPERATURES WILL START TO
FALL LATER SATURDAY...ESPECIALLY OVER OUR MINNESOTA ZONES. STRONG
WEST-NORTHWEST WINDS WILL DEVELOP SATURDAY INTO SATURDAY NIGHT...AND
WE INCREASED THEM QUITE A BIT. A WIND CHILL ADVISORY WILL LIKELY BE
NEEDED SATURDAY NIGHT OVER OUR MINNESOTA ZONES...AND EXTREME
NORTHWEST WISCONSIN ZONES.
OUTSIDE OF AN EXTENDED PERIOD OF LAKE EFFECT OF SNOW ALONG PORTIONS
OF THE SOUTH SHORE...THE MAIN FOCUS SATURDAY NIGHT INTO WEDNESDAY
WILL BE THE COLD. LOW WILL DROP INTO THE TEENS BELOW ZERO SATURDAY
NIGHT OVER OUR NORTHERN ZONES...AND SINGLE DIGITS BELOW OVER
NORTHWEST WISCONSIN. WE HAVE TEENS TO AROUND 25 BELOW ZERO SUNDAY
NIGHT AND MONDAY NIGHT AND TEENS BELOW TUESDAY NIGHT. HIGHS SUNDAY
WILL REMAIN AT OR BELOW ZERO OVER MOST OF NORTHEAST MINNESOTA...AND
ZERO TO 5 ABOVE IN NORTHWEST WISCONSIN...AND BE A FEW DEGREES COLDER
ON MONDAY.
A FAVORABLE PERIOD OF LES WILL OCCUR SATURDAY NIGHT INTO SUNDAY
NIGHT...ALTHOUGH 850MB TEMPERATURES WILL BE VERY COLD BY SUNDAY
NIGHT WHICH MAY LIMIT SNOW ACCUMULATIONS. SOME SIGNIFICANT SNOW
ACCUMULATIONS WILL BE POSSIBLE IN THE SNOWBELT SATURDAY NIGHT INTO
SUNDAY.
&&
.POINT TEMPS/POPS...
DLH 4 -1 26 20 / 10 60 70 30
INL -4 -14 17 7 / 10 60 70 50
BRD 9 1 32 19 / 10 60 20 10
HYR 7 -3 34 17 / 10 60 60 20
ASX 6 -1 29 18 / 20 60 70 30
&&
.DLH WATCHES/WARNINGS/ADVISORIES...
MN...WIND CHILL ADVISORY UNTIL NOON CST TODAY FOR MNZ010>012-019>021.
WI...NONE.
LS...NONE.
&&
$$
SHORT TERM...DAP
LONG TERM....MELDE
AVIATION...MELDE
AREA FORECAST DISCUSSION
NWS TWIN CITIES/CHANHASSEN MN
424 AM CST THU JAN 17 2013
.DISCUSSION...
OVERVIEW...PATTERN STILL FAVORING A SERIES OF ALBERTA CLIPPERS
THROUGH THE EXTENDED. THE FIRST ARRIVES TONIGHT QUICK ON THE HEELS
OF A PASSING SURFACE HIGH. THIS WILL BRING LIGHT SNOW TO NORTHERN
MN THROUGH SATURDAY. WHILE LIGHT SNOW IS ALSO POSSIBLE IN CENTRAL
MN AND PORTIONS OF WESTERN WI...THE MAIN IMPACTS WILL BE THE
DRAMATIC ARCTIC FRONT ASSOCIATED WITH THIS SYSTEM. WINDS AND
FRIGID TEMPERATURES ARE STILL EXPECTED SATURDAY NIGHT THROUGH
SUNDAY. THE WIND WILL DIMINISH MONDAY...BUT THIS WILL BE ARE
COLDEST DAY OF THE SEASON SO FAR. MANY LOCATIONS WILL NOT CLIMB
ABOVE ZERO MONDAY. THE PATTERN LOOKS TO BECOME SLIGHTLY MORE
ACTIVE IN TERMS OF PRECIPITATION FOR THE LAST WEEK IN JANUARY.
STRATUS DECK IS SLOWLY ENGULFING SOUTHERN MN AND WESTERN WI THIS
MORNING. WITH NORTHWEST FLOW AND WEAK COLD AIR ADVECTION TODAY TO
GO ALONG WITH WHAT COULD AMOUNT TO A MOSTLY CLOUDY DAY...HARD TO
EXPECT MUCH WARMING THIS AFTERNOON. LOWERED TEMPS SLIGHTLY AND ARE
MAINLY ONLY RISING TEMPS 4-7 DEGREES FROM WHERE WE CURRENTLY SIT
THIS MORNING. AN ALBERTA CLIPPER COMES IN FAST TONIGHT...BUT THE
WAVE IS WEAK INITIALLY AND DOESN`T REALLY STRENGTHEN UNTIL
SATURDAY MORNING WHEN A VIGOROUS SHORT WAVE COMES CRUISING DOWN
FROM ALASKA. AT THAT POINT...THE SURFACE CYCLONE DEEPENS 5-10 MB
IN ROUGHLY 12 HOURS. THE CLIPPER SEEMS TO BE DIABATICALLY
INTERACTING WITH LAKE SUPERIOR...WHICH MAY BE CONTRIBUTING TO THE
DEEPENING. STILL HAVE LIGHT SNOW FORECASTED ACROSS CENTRAL MN IN
NORTHERN PORTIONS OF THE MPX FORECAST AREA. WE INITIALLY GAVE
MOISTURE OVER A LARGE DEPTH OF THE ATMOSPHERE THIS MORNING ACROSS
WESTERN/CENTRAL MN...BUT WE LOSE THE RH AT SOME POINT THIS
AFTERNOON. SO...LIKE WEDNESDAY MORNING...FREEZING DRIZZLE CAN NOT
BE COMPLETELY RULED OUT WHERE SNOW IS FORECASTED LATE THIS
EVENING. WE EVENTUALLY FEEL THE COLUMN WILL BE SATURATED ABOVE -10
C...SO LIGHT SNOW SHOULD BE THE DOMINATE P-TYPE BY SUNRISE FRIDAY
MORNING.
WE INCREASED MAX TEMPS ON FRIDAY GIVEN WHAT WE MANAGED YESTERDAY
AND WHAT IS EXPECTED WITH THE WARM FRONT. WE SHOULD SEE PLENTY OF
LOWER 40S IN SOUTHERN MN. THE LONE QUESTION WOULD BE IF THE SYSTEM
SLOWS DOWN BY 3-6 HOURS AND THE SURFACE WINDS REMAIN SOUTHEAST
LONGER ON FRIDAY. IT WOULD CERTAINLY STILL BE WELL ABOVE NORMAL IF
THE SLOWER SOLUTION WOULD HAPPEN...BUT HAD ENOUGH CONFIDENCE TO
BLEND IN SOME ECMWF AND BIAS CORRECTED ECMWF TO THE PREVIOUS
FORECAST TO GIVE US A BOOST IN TEMPS. THE SOUTHERLY FLOW IS STRONG
AND MIXING SHOULD BE GOOD FOR MID JANUARY. ANY SNOW ASSOCIATED
WITH THIS FIRST CLIPPER SYSTEM /THURSDAY NIGHT AND FRIDAY/ SHOULD
BE VERY MINOR AND THE MAIN IMPACTS WILL COME FROM THE ASSOCIATED
STRONG ARCTIC FRONT. THE COMBINATION OF THE DEEPENING CLIPPER AND
BUILDING HIGH IN THE DAKOTAS ESTABLISH A VERY NICE PACKING OF
ISOBARS AND THE 17.00Z GFS/ECMWF/NAM ALL SHOW 40-50 KTS OUT OF THE
NORTHWEST BEHIND THE ARCTIC BOUNDARY. WE INCREASED TEMPERATURES
SATURDAY GIVEN THE TIMING OF THIS BOUNDARY...WHICH SHOULD LEAVE
ROOM FOR A MILD JANUARY MORNING AND EVEN EARLY AFTERNOON ACROSS
THE FORECAST AREA. HOWEVER...THE FRONT COMES IN VERY FAST AND
WESTERN MN WILL ALREADY SEE DRAMATICALLY FALLING TEMPS AND STRONG
WINDS BY SATURDAY EVENING. WE WILL LIKELY NEED A WIND SHILL
ADVISORY AS EARLY AS 00Z SUNDAY WITH THIS SURGE.
A REINFORCING SHOT OF COLDER AIR ARRIVES SUNDAY...ALTHOUGH THE
MOST DRAMATIC CHANGES IN TEMPERATURE WILL STILL OCCUR
SATURDAY/SATURDAY NIGHT. WINDS CHILLS WILL BE IN THE -25 TO -40
RANGE LATE THIS WEEKEND AND ON MONDAY...AND MONDAY WILL STRUGGLE
TO REACH ZERO IN EASTERN MN AND WI. WESTERN PORTIONS OF THE
FORECAST AREA HAVE ALMOST NO CHANCE OF REACHING ZERO ON MONDAY.
THE EXTENDED FORECAST STILL POINTS TO A BREAKDOWN OF THE STRONG
RIDGING ALONG THE WEST COAST AND A RELAXATION OF THE DEEP
TROUGHING OVER THE EASTERN CONUS. THE PREVIOUS ECMWF ENSEMBLE
MEAN AND GEFS MEAN SHOW GOOD CORRELATION THROUGH NEXT WEEK WITH
THE INCOMING SYSTEM IN THE PACIFIC NORTHWEST NEXT
WEDNESDAY. LAST NIGHTS OPERATIONAL RUNS ARE COMING AROUND AS WELL.
CHANCES FOR MORE WIDESPREAD PRECIPITATION WILL INCREASE AS THE
WEST COAST WAVE MOVES THROUGH THE NORTHERN ROCKIES AND ONTO THE
NORTEHRN PLAINS BY MIDWEEK BUT ONLY MODEST QPF AMOUNTS ARE
FORECAST. THIS IS STILL A BREAK FROM WHAT WE`VE SEEN AROUND HERE
SINCE THE HOLIDAYS. AT THIS POINT THE SYSTEM LATE NEXT WEEK
REMAINS WARM ENOUGH TO CONSIDER A RAIN/SNOW MIX...BUT STILL WAY
TOO FAR OUT THERE TO GET SERIOUS ABOUT P-TYPE.
&&
.AVIATION.../06Z TAF ISSUANCE/
MAIN FORECAST CONCERN THIS TAF PERIOD IS THE POTENTIAL FOR MVFR
CIGS TO MOVE INTO THE AREA FROM THE NORTHWEST OVERNIGHT AND
THURSDAY MORNING. 11-3.9 MICRON SATELLITE IMAGERY SHOWS A BLOB OF
LLVL MOISTURE OVER NORTH DAKOTA ALONG THE WESTERN PERIPHERY OF THE
SURFACE RIDGE. BOTH THE HRRR /CLOUDBASE/ AND RAP /925-850MB MOISTURE/ PROGS
SHOW THIS AREA OF MOISTURE BETWEEN 2000 AND 4000 FT ADVECTING INTO
THE MN BETWEEN 08Z AND 12Z...AND WI ON THURSDAY MORNING. WILL
RETAIN A SCT-BKN MVFR LEVEL DECK IN THE TAF ACCORDINGLY. THE 925MB
LAYER IS PROGGED TO DRY OUT THURSDAY AFTERNOON /MN/ AND EARLY EVE
/WI/...BUT QUICKLY BE REPLACED BY A WEST TO EAST SURGE OF
850-700MB MOISTURE BETWEEN 03Z AND 12Z FRIDAY. WILL INTRODUCE SNOW
INTO KAXN AROUND 03Z FRIDAY...BUT ONSET FOR THE REMAINDER OF THE
SITES WILL MOST LIKELY BE BEYOND THIS TAF PERIOD. NORTHWEST WINDS
AT 5 TO 10 KTS WILL PREVAIL THROUGH THE PERIOD.
KMSP...SCT MVFR LEVEL CLOUDS /2000 FT/ WILL BE POSSIBLE AFTER 12Z
THURSDAY...ALONG WITH A BKN VFR DECK /3500 FT/. THE 2KFT DECK
COULD BRIEFLY GO BROKEN ON THURSDAY MORNING...BUT CONFIDENCE IS
NOT HIGH ON THAT. CLEARING ENSUES IN THE AFTERNOON...WITH ANOTHER
ROUND OF CLOUDS /LOW-END VFR CIGS/ ARRIVING AFTER 06Z FRIDAY.
/OUTLOOK FOR KMSP/
FRI...VFR. CHC OF -SN AND MVFR VIS/CIG IN MORNING. WIND SW 5-15
KTS.
SAT...MVFR CIGS LIKELY. AFTERNOON -SN POSSIBLE. W WIND 5 KTS BECOMING NW
15-20 KTS WITH GUSTS TO 30 KTS.
SUN...CHANCE OF -SN WITH MVFR OR LOWER CIG/VIS. WINDS W 5-10 KTS
BECOMING NW 15-20 KTS LATE.
&&
.MPX WATCHES/WARNINGS/ADVISORIES...
MN...NONE.
WI...NONE.
&&
$$
CLF/LS
AREA FORECAST DISCUSSION
NWS GRAND FORKS ND
959 AM CST THU JAN 17 2013
.DISCUSSION...
THE MAIN CHALLENGE TODAY WILL BE TEMPS. SFC HIGH PRESSURE WILL
BUILD INTO THE REGION...AND TEMPS WON/T WARM TOO MUCH FROM CURRENT
READINGS. WILL TAKE A LOOK AT CURRENT TEMPS...BUT NOT EXPECTING
TOO MANY CHANGES FROM CURRENT FORECAST THIS MORNING.
&&
.AVIATION...
MIXED VFR AND MVFR CLOUD DECKS AROUND THIS MORNING WITH SOME
POTENTIAL FOR CLEARING INTO NE ND/NW MN THRU THIS AFTN. WINDS
WILL BE PRETTY LIGHT TODAY...GENERALLY 10 KTS OR LESS...BUT MAY BE
MORE VARIABLE IN DIRECTION DUE TO RATHER WEAK SFC FEATURES. WINDS
WILL TURN SOUTHERLY TONIGHT AND INCREASE TO THE 10 TO 20 KT RANGE
IN THE RRV AND ERN ND. CLOUDS WILL SPREAD OVER THE REGION AGAIN
WITH LIGHT SNOW MOVING INTO DVL-GFK BY 06Z AND THEN SPREADING
EAST. SOME MVFR CIGS AND VSBYS PSBL WITH THIS SYSTEM.
&&
.PREV DISCUSSION... /ISSUED 615 AM CST THU JAN 17 2013/
UPDATE...
FLURRIES PERSISTING LONGER THAN THOUGHT PER RADAR AND OBS. ONCE
AGAIN RAP MODEL DOING WELL AND HAS THE FLURRIES EXITING THE
SOUTHEAST FCST AREA 16-17Z. WILL MENTION FLURRIES IN MUCH OF
NW/WCNTRL MN INTO FAR SE ND UNTIL THEN AS WAVE MOVES THROUGH.
NOTING A PERIOD OF 20 TO 30 KT WIND GUST SPREADING THRU DVL BASIN
WITH CLEARING PROGRESSING SOUTHEAST QUICKLY.
PREV DISCUSSION... /ISSUED 344 AM CST THU JAN 17 2013/
SHORT TERM...
WATER VAPOR SHOWS THE RIGHT FRONT OF A 300 MB 150KT JET OVER NE
ND/NW MN THIS MORNING. A COUPLE OF WEAK 500 MB SHORT WAVES ON THE
SOUTH EDGE OF JET MAX FROM SRN SASK INTO CNTRL-SE ND. ONCE WEAK
SYSTEM MOVING THRU ERN ND ATTM INTO WCNTRL MN PRODUCING SOME
FLURRIES. MAIN RESULT OF JET MAX IS TO PRODUCE AN EXPANSIVE CLOUD
SHIELD WHICH HAS MOVED OVER ALL OF THE FCST AREA OVERNIGHT CAUSING
RISING TEMPS IN NW MN WHICH DID DROP INTO THE MID TEENS BELOW
EARLY THIS EVE. AS A RESULT OF WARMING TEMPS AND LIGHT WINDS HAVE
CANCELLED WIND CHILL ADV.
SHORT TERM MODELS SUCH AS THE RAP INSIST SOME CLEARING WILL MOVE
INTO FAR NE ND AND NW MN LATER THIS MORNING AND AFTN AND SOME
CLEARING IS NOTED IN PATCHY FASHION MOVING INTO SW MANITOBA ATTM
FROM CNTRL SASK. THUS SOME SUN PSBL LATER TODAY.
TEMPS A REAL CONCERN THRU THE PD. SFC MAP SHOWS A WK LOW NR DVL
MOVING SOUTHEAST ALONG A THERMAL BOUNDARY FROM SE SASK INTO SE
ND...NR AN ESTEVAN TO MINOT TO JAMESTOWN TO ABERDEEN LINE. TEMPS
INTO THE TEENS IN THE FAR WRN FCST AREA ATTM AND EXPECT AS WINDS
TURN A BIT MORE NORTH AFTER SUNRISE TEMPS TO FALL A BIT. REST OF
THE FCST AREA TO REMAIN CHILLY WITH HIGHS TODAY IN THE SINGLE
DIGITS...WITH TEMPS STRUGGLING TO REACH ZERO IN FAR NORTHEAST FCST
AREA WHERE COLDEST AIRMASS RESIDES.
TONIGHT WILL SEE NEXT SHORT WAVE WHICH WILL MOVE INTO CNTRL
ALBERTA MOVE SOUTHEAST. THIS SYSTEM WILL BE MORE PRESENT AT THE
925-850 MB LEVEL WHERE LOWER LEVEL WARM ADVECTION ZONE WILL
STRENGTHEN TONIGHT FROM WRN MANITOBA INTO ERN ND/NW MN. THUS DO
LOOK FOR A BAND OF WARM ADV SNOW TO EXPAND SOUTHEAST INTO DVL
BASIN BEFORE 06Z AND THEN SPREAD EAST OVERNIGHT...WITH WARM ADV
MAXIMIZING IN NW MN LATE TONIGHT WHERE 1-2 INCHES OF SNOW MAY FALL
UP IN THE ROSEAU-WARROAD-BAUDETTE AREAS. STRONG WARMING AT THE SFC
TO AS WINDS TURN SOUTHERLY AND INCREASE TO 10 TO 20 KTS. AS WHAT
OCCURRED A FEW DAYS AGO EXPECT RISING TEMPS OVER ERN ND TONIGHT
REACHING THE 20S. AIRMASS TO REMAIN RATHER MILD INTO FRIDAY AS
WELL SOUTH OF A STRONGER SHORT WAVE AND SFC LOW WHICH WILL MOVE
FROM NORTHERN ALBERTA SOUTHEAST TOWARD LAKE OF THE WOODS REGION
SATURDAY. SOME LIGHT SNOW WITH THIS SYSTEM AS WELL...BUT MOSTLY
OVER FAR NW MN INTO ONTARIO. TEMPS FRIDAY SOUTH OF THE LOW WILL
RISE INTO THE LOW-MID 30S AS 925 MB TEMPS RISE TO ABOVE ZERO IN
AREAS FROM DVL TO FARGO TO FERGUS FALLS SOUTHWARD.
SATURDAY PROMISES TO BE AN INTERESTING DAY AS SFC LOW MOVES FROM
LAKE OF THE WOODS REGION SOUTHEAST AND IN ITS WAKE WILL BE STRONG
COLD ADVECTION WITH 925 MB TEMPS DROPPING SOME 20 DEGREES DURING
THE DAY SATURDAY WITH 25 TO 30 KT SFC WINDS FROM THE NORTH. HOURLY
TEMPS A REAL HEADACHE AS COULD WELL BE IN THE 20S TO START IN SE
ND/WCNTRL MN...BUT ALL AREAS WILL SEE FALLING TEMPS INTO THE
SINGLE DIGITS ABOVE AND BELOW ZERO IN THE AFTN WITH WIND CHILLS IN
THE TEENS AND 20S BELOW.
HIGH PRESSURE WILL MOVE IN SAT NIGHT WITH LIGHTER WINDS AND MAYBE
A PERIOD OF RATHER CLEAR SKY ESP IN THE EVENING. THIS SHOULD ALLOW
FOR WIDESPREAD TEENS BLO ZERO...BUT CLOUDS IN ADVANCE OF THE NEXT
SYSTEM DUE TO ARRIVE SUNDAY WILL LIKELY PREVENT ANY HUGE TEMP
DROP.
LONG TERM (SUNDAY-WEDNESDAY)...
THE 00Z GFS/ECMWF/GEM ARE ALL IN GOOD AGREEMENT THROUGH MUCH OF THE
PERIOD WITH THE OVERALL SYNOPTIC PATTERN EVOLUTION. STRONGLY
MERIDIONAL NORTHWESTERLY FLOW ALOFT IN RESPONSE TO HIGH AMPLITUDE
RIDGING ACROSS WESTERN NORTH AMERICA WILL DRIVE ARCTIC AIR SOUTH ACROSS
THE NORTHERN PLAINS. BOTH THE GFS/ECMWF SHOW 925 MB TEMPS FALLING
INTO THE -25C TO -30C RANGE BY 12Z MONDAY...BEFORE SLOW MODIFICATION
OF THE AIR MASS TAKES PLACE BY THE END OF THE PERIOD AS THE UPPER
AIR PATTERN BEGINS TO DE-AMPLIFY AND THICKNESSES RISE. HIGH TEMPS
WILL GENERALLY BE BELOW ZERO IN MOST AREAS SUNDAY AND
MONDAY...RECOVERING INTO THE SINGLE DIGITS AND TEENS BY WEDNESDAY.
LOW TEMPS LIKELY WILL DEPEND ON CLOUDS AND SFC HIGH POSITION TO SOME
DEGREE...BUT TEMPS DOWN TO NEAR OR BELOW -20F EXPECTED IN MANY AREAS
ON SUNDAY NIGHT AND AGAIN IN SOME AREAS ON MONDAY NIGHT.
AS HAS BEEN THE CASE RECENTLY WITHIN THE NORTHWEST FLOW ALOFT...WEAK
EMBEDDED WAVES MAY BRING PERIODIC CHANCES FOR LIGHT SNOW AND
FLURRIES...BUT THE TIMING AND LOCATION OF THESE SYSTEMS IS UNCERTAIN
AT THIS RANGE. MAINTAINED LOW POPS FOR SUNDAY WITH ONE SYSTEM
DROPPING OUT OF CANADA. SOME INDICATION OF ANOTHER WEAK SYSTEM FOR
MONDAY NIGHT OR TUESDAY...BUT WILL STICK WITH DRY FORECAST FOR NOW
DUE TO LOW CONFIDENCE. OTHERWISE...A SERIES OF ARCTIC HIGHS DROPPING
SOUTH WILL RESULT IN FAIRLY TRANQUIL WEATHER FOR MUCH OF THE PERIOD.
&&
.FGF WATCHES/WARNINGS/ADVISORIES...
ND...NONE.
MN...NONE.
&&
$$
DK
AREA FORECAST DISCUSSION...UPDATED
NWS GRAND FORKS ND
615 AM CST THU JAN 17 2013
.UPDATE...
FLURRIES PERSISTING LONGER THAN THOUGHT PER RADAR AND OBS. ONCE
AGAIN RAP MODEL DOING WELL AND HAS THE FLURRIES EXITING THE
SOUTHEAST FCST AREA 16-17Z. WILL MENTION FLURRIES IN MUCH OF
NW/WCNTRL MN INTO FAR SE ND UNTIL THEN AS WAVE MOVES THROUGH.
NOTING A PERIOD OF 20 TO 30 KT WIND GUST SPREADING THRU DVL BASIN
WITH CLEARING PROGRESSING SOUTHEAST QUICKLY.
&&
.PREV DISCUSSION... /ISSUED 344 AM CST THU JAN 17 2013/
SHORT TERM...
WATER VAPOR SHOWS THE RIGHT FRONT OF A 300 MB 150KT JET OVER NE
ND/NW MN THIS MORNING. A COUPLE OF WEAK 500 MB SHORT WAVES ON THE
SOUTH EDGE OF JET MAX FROM SRN SASK INTO CNTRL-SE ND. ONCE WEAK
SYSTEM MOVING THRU ERN ND ATTM INTO WCNTRL MN PRODUCING SOME
FLURRIES. MAIN RESULT OF JET MAX IS TO PRODUCE AN EXPANSIVE CLOUD
SHIELD WHICH HAS MOVED OVER ALL OF THE FCST AREA OVERNIGHT CAUSING
RISING TEMPS IN NW MN WHICH DID DROP INTO THE MID TEENS BELOW
EARLY THIS EVE. AS A RESULT OF WARMING TEMPS AND LIGHT WINDS HAVE
CANCELLED WIND CHILL ADV.
SHORT TERM MODELS SUCH AS THE RAP INSIST SOME CLEARING WILL MOVE
INTO FAR NE ND AND NW MN LATER THIS MORNING AND AFTN AND SOME
CLEARING IS NOTED IN PATCHY FASION MOVING INTO SW MANITOBA ATTM
FROM CNTRL SASK. THUS SOME SUN PSBL LATER TODAY.
TEMPS A REAL CONCERN THRU THE PD. SFC MAP SHOWS A WK LOW NR DVL
MOVING SOUTHEAST ALONG A THERMAL BOUNDARY FROM SE SASK INTO SE
ND...NR AN ESTEVAN TO MINOT TO JAMESTOWN TO ABERDEEN LINE. TEMPS
INTO THE TEENS IN THE FAR WRN FCST AREA ATTM AND EXPECT AS WINDS
TURN A BIT MORE NORTH AFTER SUNRISE TEMPS TO FALL A BIT. REST OF
THE FCST AREA TO REMAIN CHILLY WITH HIGHS TODAY IN THE SINGLE
DIGITS...WITH TEMPS STRUGGLING TO REACH ZERO IN FAR NORTHEAST FCST
AREA WHERE COLDEST AIRMASS RESIDES.
TONIGHT WILL SEE NEXT SHORT WAVE WHICH WILL MOVE INTO CNTRL
ALBERTA MOVE SOUTHEAST. THIS SYSTEM WILL BE MORE PRESENT AT THE
925-850 MB LEVEL WHERE LOWER LEVEL WARM ADVECTION ZONE WILL
STRENGTHEN TONIGHT FROM WRN MANITOBA INTO ERN ND/NW MN. THUS DO
LOOK FOR A BAND OF WARM ADV SNOW TO EXPAND SOUTHEAST INTO DVL
BASIN BEFORE 06Z AND THEN SPREAD EAST OVERNIGHT...WITH WARM ADV
MAXIMIZING IN NW MN LATE TONIGHT WHERE 1-2 INCHES OF SNOW MAY FALL
UP IN THE ROSEAU-WARROAD-BAUDETTE AREAS. STRONG WARMING AT THE SFC
TO AS WINDS TURN SOUTHERLY AND INCREASE TO 10 TO 20 KTS. AS WHAT
OCCURRED A FEW DAYS AGO EXPECT RISING TEMPS OVER ERN ND TONIGHT
REACHING THE 20S. AIRMASS TO REMAIN RATHER MILD INTO FRIDAY AS
WELL SOUTH OF A STRONGER SHORT WAVE AND SFC LOW WHICH WILL MOVE
FROM NORTHERN ALBERTA SOUTHEAST TOWARD LAKE OF THE WOODS REGION
SATURDAY. SOME LIGHT SNOW WITH THIS SYSTEM AS WELL...BUT MOSTLY
OVER FAR NW MN INTO ONTARIO. TEMPS FRIDAY SOUTH OF THE LOW WILL
RISE INTO THE LOW-MID 30S AS 925 MB TEMPS RISE TO ABOVE ZERO IN
AREAS FROM DVL TO FARGO TO FERGUS FALLS SOUTHWARD.
SATURDAY PROMISES TO BE AN INTERESTING DAY AS SFC LOW MOVES FROM
LAKE OF THE WOODS REGION SOUTHEAST AND IN ITS WAKE WILL BE STRONG
COLD ADVECTION WITH 925 MB TEMPS DROPPING SOME 20 DEGREES DURING
THE DAY SATURDAY WITH 25 TO 30 KT SFC WINDS FROM THE NORTH. HOURLY
TEMPS A REAL HEADACHE AS COULD WELL BE IN THE 20S TO START IN SE
ND/WCNTRL MN...BUT ALL AREAS WILL SEE FALLING TEMPS INTO THE
SINGLE DIGITS ABOVE AND BELOW ZERO IN THE AFTN WITH WIND CHILLS IN
THE TEENS AND 20S BELOW.
HIGH PRESSURE WILL MOVE IN SAT NIGHT WITH LIGHTER WINDS AND MAYBE
A PERIOD OF RATHER CLEAR SKY ESP IN THE EVENING. THIS SHOULD ALLOW
FOR WIDESPREAD TEENS BLO ZERO...BUT CLOUDS IN ADVANCE OF THE NEXT
SYSTEM DUE TO ARRIVE SUNDAY WILL LIKELY PREVENT ANY HUGE TEMP
DROP.
LONG TERM (SUNDAY-WEDNESDAY)...
THE 00Z GFS/ECMWF/GEM ARE ALL IN GOOD AGREEMENT THROUGH MUCH OF THE
PERIOD WITH THE OVERALL SYNOPTIC PATTERN EVOLUTION. STRONGLY
MERIDIONAL NORTHWESTERLY FLOW ALOFT IN RESPONSE TO HIGH AMPLITUDE
RIDGING ACROSS WESTERN NORTH AMERICA WILL DRIVE ARCTIC AIR SOUTH ACROSS
THE NORTHERN PLAINS. BOTH THE GFS/ECMWF SHOW 925 MB TEMPS FALLING
INTO THE -25C TO -30C RANGE BY 12Z MONDAY...BEFORE SLOW MODIFICATION
OF THE AIR MASS TAKES PLACE BY THE END OF THE PERIOD AS THE UPPER
AIR PATTERN BEGINS TO DE-AMPLIFY AND THICKNESSES RISE. HIGH TEMPS
WILL GENERALLY BE BELOW ZERO IN MOST AREAS SUNDAY AND
MONDAY...RECOVERING INTO THE SINGLE DIGITS AND TEENS BY WEDNESDAY.
LOW TEMPS LIKELY WILL DEPEND ON CLOUDS AND SFC HIGH POSITION TO SOME
DEGREE...BUT TEMPS DOWN TO NEAR OR BELOW -20F EXPECTED IN MANY AREAS
ON SUNDAY NIGHT AND AGAIN IN SOME AREAS ON MONDAY NIGHT.
AS HAS BEEN THE CASE RECENTLY WITHIN THE NORTHWEST FLOW ALOFT...WEAK
EMBEDDED WAVES MAY BRING PERIODIC CHANCES FOR LIGHT SNOW AND
FLURRIES...BUT THE TIMING AND LOCATION OF THESE SYSTEMS IS UNCERTAIN
AT THIS RANGE. MAINTAINED LOW POPS FOR SUNDAY WITH ONE SYSTEM
DROPPING OUT OF CANADA. SOME INDICATION OF ANOTHER WEAK SYSTEM FOR
MONDAY NIGHT OR TUESDAY...BUT WILL STICK WITH DRY FORECAST FOR NOW
DUE TO LOW CONFIDENCE. OTHERWISE...A SERIES OF ARCTIC HIGHS DROPPING
SOUTH WILL RESULT IN FAIRLY TRANQUIL WEATHER FOR MUCH OF THE PERIOD.
AVIATION...
MIXED VFR AND MVFR CLOUD DECKS AROUND THIS MORNING WITH SOME
POTENTIAL FOR CLEARING INTO NE ND/NW MN LATER THIS MORNING THRU
THIS AFTN. WINDS WILL BE PRETTY LIGHT TODAY...GENERALLY 10 KTS OR
LESS...BUT MAY BE MORE VARIABLE IN DIRECTION DUE TO RATHER WEAK
SFC FEATURES. WINDS WILL TURN SOUTHERY TONIGHT AND INCREASE TO THE
10 TO 20 KT RANGE IN THE RRV AND ERN ND. CLOUDS WILL SPREAD OVER
THE REGION AGAIN WITH LIGHT SNOW MOVING INTO DVL-GFK BY 06Z AND
THEN SPREADING EAST. SOME MVFR CIGS AND VSBYS PSBL WITH THIS
SYSTEM.
&&
.FGF WATCHES/WARNINGS/ADVISORIES...
ND...NONE.
MN...NONE.
&&
$$
RIDDLE/MAKOWSKI
AREA FORECAST DISCUSSION
NWS WILMINGTON OH
954 AM EST THU JAN 17 2013
.SYNOPSIS...
CLOUD COVER WILL CONTINUE FOR MUCH OF TODAY AS THE OHIO VALLEY
RESIDES BETWEEN LOW PRESSURE TO THE SOUTH...AND HIGH PRESSURE TO
THE WEST. THE HIGH WILL BUILD EASTWARD TONIGHT...BRINGING THE AREA
A PERIOD OF SEASONABLE TEMPERATURES AND FAIR WEATHER THROUGH
SATURDAY. SOME SNOW SHOWERS WILL BECOME POSSIBLE SATURDAY NIGHT AS
AN ARCTIC AIRMASS BEGINS TO MOVE INTO OUR REGION.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
AMPLE CLOUD COVER EXTENDS ACROSS THE AREA UNDER A DENSE HIGH
CLOUD CANOPY ASSOCIATED WITH A STRONG UPPER LEVEL JET. PATCHES OF
LOW CLOUDS ARE ALSO OCCURRING UNDER THIS DECK PRIMARILY ASSOCIATED
WITH MOIST LOW LEVEL NORTHERLY FLOW. MODELS ARE IN DISAGREEMENT ON
HOW TO HANDLE THIS LOW LEVEL MOISTURE AS WE GO THROUGH THE DAY.
THE HIGH CLOUDS WILL GRADUALLY SHIFT EAST AS THE JET MAX EXITS OUR
REGION TODAY. THE RAP INDICATES THAT MUCH OF THE LOW CLOUD COVER
WILL CONTINUE THROUGHOUT THE DAY. THE NAM SUGGESTS CLEARING THIS
AFTERNOON. FOLLOWING THE PERSISTENT TREND FOR THE PAST SEVERAL
DAYS...WILL BE PESSIMISTIC ABOUT CLEARING TODAY. THIS WILL RESULT
IN HIGH TEMPERATURES IN THE 30S.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH SUNDAY/...
A WEAK COLD FRONT WILL PASS ACROSS THE AREA TONIGHT. THIS FRONT
WILL BE MOISTURE STARVED SO KEPT ANY MENTION OF FLURRIES...THAT
HI RES MODELS ARE SUGGESTING...OUT OF THE FORECAST. HIGH PRESSURE
WILL BEGIN TO BUILD BEHIND THIS WEAK FRONT LATE TONIGHT AND INTO
THE DAY FRIDAY. THIS SHOULD FINALLY PROVIDE FOR SOME CLEARING
SKIES...ESPECIALLY ACROSS THE SOUTH AND CLOSER TO THE RIDGE
CENTER. TEMPERATURES WILL REMAIN GENERALLY SEASONABLE THURSDAY
NIGHT AND FRIDAY.
BY FRIDAY NIGHT SOME RETURN FLOW WILL DEVELOP WITH THE LOW LEVEL
PRESSURE GRADIENT INCREASING AS THE RIDGE SHIFTS ACROSS THE
SOUTHEASTERN CONUS AND LOW PRESSURE BEGINS TO PUSH EASTWARD
ACROSS THE GREAT LAKES. WARMER TEMPERATURES MOVING IN AS WELL AS
WINDS KEEPING UP OVERNIGHT WILL LIKELY KEEP TEMPERATURES IN THE
UPPER 20S FOR THE MOST PART.
SURFACE GRADIENT WILL TIGHTEN FURTHER ON SATURDAY AS THE LOW
PASSES TO OUR NORTH WHICH WILL PROVIDE BREEZY SOUTHWEST WINDS AND
A RATHER MILD DAY. TEMPERATURES WILL LIKELY TOP OUT IN THE MIDDLE
40S ACROSS THE NORTH TO THE LOWER 50S ACROSS THE SOUTH.
A DEEP UPPER TROUGH BEGINS TO DIG SOUTH INTO OUR REGION SATURDAY
NIGHT AS THE SURFACE LOW REACHES THE EASTERN GREAT LAKES. AS THIS
OCCURS...AN ARCTIC COLD FRONT WILL ARRIVE AT OUR DOORSTEP. SOME
LIGHT PRECIPITATION IN THE FORM OF SNOW SHOWERS LOOKS
POSSIBLE BEHIND THIS FRONT...ESPECIALLY ACROSS THE NORTHERN
PORTIONS OF THE FORECAST AREA. BEHIND THIS STRONG COLD
FRONT...BREEZY NORTHWEST WINDS WILL BRING MUCH COLDER AND DRIER
AIR ACROSS THE REGION SUNDAY.
&&
.LONG TERM /SUNDAY NIGHT THROUGH WEDNESDAY/...
WEAK SHORT WAVES WILL BRING A SLIGHT CHANCE FOR SNOW SHOWERS ON
MONDAY AND AGAIN ON TUESDAY NIGHT. OTHERWISE...PRECIPITATION IS
NOT EXPECTED IN THE MODIFIED ARCTIC AIRMASS.
ABOVE NORMAL HIGHS ARE EXPECTED FOR SATURDAY IN A BRIEF ROUND OF
WARM ADVECTION AND SOLAR HEATING. IN THE COLDER AIRMASS THAT WILL BE
AROUND FOR THE REST OF THE PERIOD...TEMPERATURES WILL BE WELL BELOW
NORMAL. TUESDAY MAY BE THE COLDEST DAY...WITH HIGHS NOT FORECAST TO
REACH 20 IN MOST LOCATIONS.
&&
.AVIATION /15Z THURSDAY THROUGH MONDAY/...
LOW LEVEL CLOUD COVER IS SOMEWHAT TOUGH TO DISCERN THIS MORNING AS
THICK CIRRUS CLOUDS ARE BLOCKING ANY HELP FROM THE IR SATELLITE
IMAGES. BASED ON SURFACE OBS...IT DOES APPEAR THAT THE MVFR SC
DECK IS EXPANDING ACROSS NORTHERN PORTIONS OF OUR FA. THE LATEST
RAP IS INDICATING SOME DECENT 925 MB MOISTURE PUSHING DOWN ACROSS
OUR AREA THROUGH AT LEAST THE REST OF THE MORNING...BUT THE 06Z
NAM IS NOT AS MOIST. GIVEN THAT THE LOW LEVEL CAA WILL CONTINUE
INTO THIS AFTERNOON...WOULD BE INCLINED TO THINK THE MVFR CLOUDS
WOULD STICK AROUND FOR A WHILE. WILL THEREFORE BE A LITTLE SLOWER
TO SCATTER THINGS OUT THIS AFTERNOON BUT DO EXPECT TO EVENTUALLY
SEE AT LEAST SOME PARTIAL CLEARING. LOW LEVEL MOISTURE IS PROGGED
TO INCREASE ACROSS NORTHERN OHIO AGAIN LATER TONIGHT. THIS MAY
ALLOW FOR SOME SC TO SNEAK BACK DOWN TOWARD THE NORTHERN TAFS LATE
IN THE PERIOD.
OUTLOOK...NO SIGNIFICANT WEATHER IS EXPECTED.
&&
.ILN WATCHES/WARNINGS/ADVISORIES...
OH...NONE.
KY...NONE.
IN...NONE.
&&
$$
SYNOPSIS...LATTO
NEAR TERM...HICKMAN/LATTO
SHORT TERM...LATTO
LONG TERM...CONIGLIO
AVIATION...JGL
AREA FORECAST DISCUSSION
NWS WILMINGTON OH
637 AM EST THU JAN 17 2013
.SYNOPSIS...
CLOUD COVER WILL CONTINUE FOR MUCH OF TODAY AS THE OHIO VALLEY
RESIDES BETWEEN LOW PRESSURE TO THE SOUTH...AND HIGH PRESSURE TO
THE WEST. THE HIGH WILL BUILD EASTWARD TONIGHT...BRINGING THE AREA
A PERIOD OF SEASONABLE TEMPERATURES AND FAIR WEATHER THROUGH
SATURDAY. SOME SNOW SHOWERS WILL BECOME POSSIBLE SATURDAY NIGHT AS
AN ARCTIC AIRMASS BEGINS TO MOVE INTO OUR REGION.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
AMPLE CLOUD COVER EXTENDS ACROSS THE AREA UNDER A DENSE HIGH
CLOUD CANOPY ASSOCIATED WITH A STRONG UPPER LEVEL JET. PATCHES OF
LOW CLOUDS ARE ALSO OCCURRING UNDER THIS DECK PRIMARILY ASSOCIATED
WITH MOIST LOW LEVEL NORTHERLY FLOW. MODELS ARE IN DISAGREEMENT ON
HOW TO HANDLE THIS LOW LEVEL MOISTURE AS WE GO THROUGH THE DAY.
THE HIGH CLOUDS WILL GRADUALLY SHIFT EAST AS THE JET MAX EXITS OUR
REGION TODAY. THE RAP INDICATES THAT MUCH OF THE LOW CLOUD COVER
WILL CONTINUE THROUGHOUT THE DAY. THE NAM SUGGESTS CLEARING THIS
AFTERNOON. FOLLOWING THE PERSISTENT TREND FOR THE PAST SEVERAL
DAYS...WILL BE PESSIMISTIC ABOUT CLEARING TODAY. THIS WILL RESULT
IN HIGH TEMPERATURES PEAKING IN THE MIDDLE 30S.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH SUNDAY/...
A WEAK COLD FRONT WILL PASS ACROSS THE AREA TONIGHT. THIS FRONT
WILL BE MOISTURE STARVED SO KEPT ANY MENTION OF FLURRIES...THAT
HI RES MODELS ARE SUGGESTING...OUT OF THE FORECAST. HIGH PRESSURE
WILL BEGIN TO BUILD BEHIND THIS WEAK FRONT LATE TONIGHT AND INTO
THE DAY FRIDAY. THIS SHOULD FINALLY PROVIDE FOR SOME CLEARING
SKIES...ESPECIALLY ACROSS THE SOUTH AND CLOSER TO THE RIDGE
CENTER. TEMPERATURES WILL REMAIN GENERALLY SEASONABLE THURSDAY
NIGHT AND FRIDAY.
BY FRIDAY NIGHT SOME RETURN FLOW WILL DEVELOP WITH THE LOW LEVEL
PRESSURE GRADIENT INCREASING AS THE RIDGE SHIFTS ACROSS THE
SOUTHEASTERN CONUS AND LOW PRESSURE BEGINS TO PUSH EASTWARD
ACROSS THE GREAT LAKES. WARMER TEMPERATURES MOVING IN AS WELL AS
WINDS KEEPING UP OVERNIGHT WILL LIKELY KEEP TEMPERATURES IN THE
UPPER 20S FOR THE MOST PART.
SURFACE GRADIENT WILL TIGHTEN FURTHER ON SATURDAY AS THE LOW
PASSES TO OUR NORTH WHICH WILL PROVIDE BREEZY SOUTHWEST WINDS AND
A RATHER MILD DAY. TEMPERATURES WILL LIKELY TOP OUT IN THE MIDDLE
40S ACROSS THE NORTH TO THE LOWER 50S ACROSS THE SOUTH.
A DEEP UPPER TROUGH BEGINS TO DIG SOUTH INTO OUR REGION SATURDAY
NIGHT AS THE SURFACE LOW REACHES THE EASTERN GREAT LAKES. AS THIS
OCCURS...AN ARCTIC COLD FRONT WILL ARRIVE AT OUR DOORSTEP. SOME
LIGHT PRECIPITATION IN THE FORM OF SNOW SHOWERS LOOKS
POSSIBLE BEHIND THIS FRONT...ESPECIALLY ACROSS THE NORTHERN
PORTIONS OF THE FORECAST AREA. BEHIND THIS STRONG COLD
FRONT...BREEZY NORTHWEST WINDS WILL BRING MUCH COLDER AND DRIER
AIR ACROSS THE REGION SUNDAY.
&&
.LONG TERM /SUNDAY NIGHT THROUGH WEDNESDAY/...
WEAK SHORT WAVES WILL BRING A SLIGHT CHANCE FOR SNOW SHOWERS ON
MONDAY AND AGAIN ON TUESDAY NIGHT. OTHERWISE...PRECIPITATION IS
NOT EXPECTED IN THE MODIFIED ARCTIC AIRMASS.
ABOVE NORMAL HIGHS ARE EXPECTED FOR SATURDAY IN A BRIEF ROUND OF
WARM ADVECTION AND SOLAR HEATING. IN THE COLDER AIRMASS THAT WILL BE
AROUND FOR THE REST OF THE PERIOD...TEMPERATURES WILL BE WELL BELOW
NORMAL. TUESDAY MAY BE THE COLDEST DAY...WITH HIGHS NOT FORECAST TO
REACH 20 IN MOST LOCATIONS.
&&
.AVIATION /12Z THURSDAY THROUGH MONDAY/...
LOW LEVEL CLOUD COVER IS SOMEWHAT TOUGH TO DISCERN THIS MORNING AS
THICK CIRRUS CLOUDS ARE BLOCKING ANY HELP FROM THE IR SATELLITE
IMAGES. BASED ON SURFACE OBS...IT DOES APPEAR THAT THE MVFR SC
DECK IS EXPANDING ACROSS NORTHERN PORTIONS OF OUR FA. THE LATEST
RAP IS INDICATING SOME DECENT 925 MB MOISTURE PUSHING DOWN ACROSS
OUR AREA THROUGH AT LEAST THE REST OF THE MORNING...BUT THE 06Z
NAM IS NOT AS MOIST. GIVEN THAT THE LOW LEVEL CAA WILL CONTINUE
INTO THIS AFTERNOON...WOULD BE INCLINED TO THINK THE MVFR CLOUDS
WOULD STICK AROUND FOR A WHILE. WILL THEREFORE BE A LITTLE SLOWER
TO SCATTER THINGS OUT THIS AFTERNOON BUT DO EXPECT TO EVENTUALLY
SEE AT LEAST SOME PARTIAL CLEARING. LOW LEVEL MOISTURE IS PROGGED
TO INCREASE ACROSS NORTHERN OHIO AGAIN LATER TONIGHT. THIS MAY
ALLOW FOR SOME SC TO SNEAK BACK DOWN TOWARD THE NORTHERN TAFS LATE
IN THE PERIOD.
OUTLOOK...NO SIGNIFICANT WEATHER IS EXPECTED.
&&
.ILN WATCHES/WARNINGS/ADVISORIES...
OH...NONE.
KY...NONE.
IN...NONE.
&&
$$
SYNOPSIS...LATTO
NEAR TERM...LATTO
SHORT TERM...LATTO
LONG TERM...CONIGLIO
AVIATION...JGL
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
1001 AM EST THU JAN 17 2013
.SYNOPSIS...
A WEAK COLD FRONT WILL PRESS IN FROM THE NORTHWEST TODAY. AT THE
SAME TIME...A STORM SYSTEM WILL PASS JUST TO THE SOUTH OF THE
STATE. AFTER A COLD DAY ON FRIDAY...TEMPERATURES WILL MODERATE A
BIT ON SATURDAY BEFORE MUCH COLDER AIR ARRIVES SUNDAY.
TEMPERATURES WILL DIP TO NEAR OR BELOW ZERO IN PARTS OF THE AREA
NEXT WEEK AS THE COLDEST AIR OF THE SEASON MOVES IN.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
10 AM UPDATE...
THICK CLOUD COVER CONTINUES TO STREAM NE OVER THE AREA FROM THE
DEVELOPING WAVE OVER THE SERN US. NRN EDGE OF THE PRECIP JUST
MAKING INTO SOUTHERN DELAWARE...SHOULD REMAIN SOUTH OF THE BORDER
TODAY.
ELSEWHERE OVER THE NW SOME PATCHY FREEZING DRIZZLE IS POSSIBLE
OVER SOME OF THE RIDGES...OTHERWISE NOTHING MORE THAN A FEW
SCATTERED LIGHT SNOW SHOWERS WILL OCCUR.
THE ABUNDANCE OF CLOUDS AND THE COLD AIR ADVECTION TODAY WILL
CAUSE TEMPS TO STAY RATHER STEADY OVER MUCH OF THE AREA...AND EVEN
DROP A FEW DEGS IN THE NWRN THIRD OF THE AREA.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH SUNDAY/...
GFS AND NAM KEEP THE SRN STREAM SYSTEM ROLLING TO THE EAST AND
NEVER REALLY THREATEN OUR SERN COS WITH PRECIP. ECMWF AND ONE OR
TWO MEMBERS OF THE GEFS STILL NUDGE VERY LIGHT PRECIP INTO THE
EXTREME SE...WHICH IS JUST ENOUGH TO KEEP A 20 POP THERE FOR THE
EVENING. BUT THEN THE WAVE DEEPENS OFF SHORE AND PULLS IN THE COLD
AIR FOR FRIDAY. CLEARING IS POSSIBLE ON FRIDAY AS THE ADVECTION
CHANGES SIGN IN THE AFTN...RAISING THE 8H TEMPS 10C IN JUST
3-4HRS. THE NW FLOW ALOFT KEEPS IT ACTIVE AND UNSETTLED THROUGH
THE PERIOD. THE 1035MB HIGH OFF TO OUR SOUTH AND 8H TEMPS RISING
INTO THE BLACK ON SAT WILL MAKE IT VERY LIKELY THAT WE WILL
ECLIPSE NORMAL MAXES BY 5 TO 10F ON SAT.
THE MOST INTERESTING PERIOD OF THE ENTIRE FORECAST IS SAT NIGHT
AND SUNDAY MORNING. TIMING OF A VERY STRONG/RAPID CHANGE IN AIR
MASS IS FAIRLY CONSISTENT AMONG THE NUMERICAL GUIDANCE. THE FRONT
WILL BLOW THROUGH SOMETIME AROUND OR AFTER MIDNIGHT IN THE NW AND
SHORTLY AFTER SUNRISE IN THE SE. THIS SORT OF SET UP IS VERY
FAVORABLE FOR INTENSE SNOW SHOWERS/SQUALLS. HOWEVER...THE
EXPECTED NIGHTTIME PASSAGE COULD LESSEN THE INTENSITY OF ANY
SQUALLS WITHOUT THE MODEST INCREASE IN INSTABILITY/MIXING POSSIBLE
DURING THE DAYLIGHT HOURS. ANOTHER POSITIVE THING IS THAT IT
SHOULD OCCUR IN THE OVERNIGHT AND NOT EVEN ON A SCHOOL/WORK-DAY
MORNING. HAVE CONTINUED THE MENTION OF THE POSSIBILITY OF SQUALLS
IN THE HWO...DUE TO THE POTENTIAL TRAVEL IMPACT RATHER THAN ANY
HARD AND FAST SNOW OR ICE CRITERIA. TEMPS DROP BACK ON SUNDAY TO
5 OR 10F BELOW NORMALS. HAVE ALLOWED FOR JUST A FEW DEG RISE IN
TEMPS...BUT IT COULD BE ANOTHER STEADY OR SLIGHT DROP DURING THE
DAYLIGHT HRS.
&&
.LONG TERM /SUNDAY NIGHT THROUGH WEDNESDAY/...
THE PATTERN LOOKS COLD HEADING INTO NEXT WEEK WITH HIGH
CONFIDENCE IN BELOW NORMAL TEMPERATURES. ASIDE FROM OCNL LAKE
EFFECT SNOW SHOWERS AND SCT FLURRIES...PRECIPITATION SHOULD BE
HARD TO COME BY WITH VERY DRY MODIFIED ARCTIC AIR PERSISTING THRU
THE END OF THE PD.
&&
.AVIATION /15Z THURSDAY THROUGH MONDAY/...
A SURGE OF HIGHER MOISTURE AHEAD OF APPROACHING COLD FRONT WILL
ASCEND THE W MTNS...PRODUCING A PERIOD OF IFR CIGS AT BFD AND JST
EARLY THIS AM. ACROSS THE RIDGE/VALLEY REGION...MVFR CIGS BEING
REPORTED AT AOO/UNV/IPT AT 11Z.
COLD FRONT WILL PUSH THRU CENTRAL PA LATER THIS MORNING...USHERING
IN A DRIER AIR MASS AND RISING CIGS. LATEST RAP LOW LVL MOISTURE
FIELDS SUGGEST BFD WILL RISE TO MVFR CIGS BTWN 12Z-13Z AND JST
WILL FOLLOW BY ARND 14Z. IN THE WAKE OF THE FRONT...MOISTURE FROM
LK ERIE WILL ASCEND THE NW MTNS...LIKELY RESULTING IN MVFR CIGS
PERSISTING AT BFD UNTIL AT LEAST MID AFTN. FURTHER
SOUTH...SOUNDINGS SUGGEST THE POSSIBILITY OF LINGERING MVFR CIGS
AT JST/UNV/AOO THRU ARND MIDDAY. HOWEVER...DOWNSLOPING FLOW ACROSS
THE SUSQ VALLEY SHOULD ENSURE VFR CONDS AT MDT AND LNS THROUGH
TODAY.
OUTLOOK...
FRI...AM -SHSN/MVFR CIGS POSS W MTNS.
SAT...NO SIG WX EXPECTED.
SUN-MON...SHSN/MVFR POSS W MTNS.
&&
.CTP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...DANGELO/LA CORTE
NEAR TERM...DANGELO/LA CORTE
SHORT TERM...DANGELO
LONG TERM...STEINBUGL
AVIATION...FITZGERALD
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
641 AM EST THU JAN 17 2013
.SYNOPSIS...
A WEAK COLD FRONT WILL PRESS IN FROM THE NORTHWEST TODAY. AT THE
SAME TIME...A STORM SYSTEM WILL PASS JUST TO THE SOUTH OF THE
STATE. AFTER A COLD DAY ON FRIDAY...TEMPERATURES WILL MODERATE A
BIT ON SATURDAY BEFORE MUCH COLDER AIR ARRIVES SUNDAY.
TEMPERATURES WILL DIP INTO THE SINGLE DIGITS IN PARTS OF THE AREA
NEXT WEEK AS THE COLDEST AIR OF THE SEASON MOVES IN.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
6 AM...
TEMPS STILL AROUND 40 ALONG THE SRN BORDER...BUT WIND HAS VEERED
SLIGHTLY. THE HIGH CLOUDS ARE THICK ENOUGH TO MAKE VIRGA SEEN ON
THE RADAR AND REMARKED IN OBS AT KMDT. LOW CLOUDS COVER MOST OF
THE AREA NOW. A COLD FRONT IS DROPPING ACROSS THE LOWER GREAT
LAKES AND WILL TURN THE WINDS MORE NORTHERLY SOON. ENOUGH
FRICTION/MOISTURE FLUX WILL CREATE SHSN IN THE NW...BUT ANY ACCUMS
SHOULD STAY IN THE SNOW BELT THIS MORNING OR EARLY AFTN. A FEW
FLURRIES COULD GET OFF THE ALLEGHENIES...BUT WILL NOT MENTION MUCH
S OR E OF CLEARFIELD AND WELLSBORO. THE ABUNDANCE OF CLOUDS AND
THE COLD AIR ADVECTION TODAY WILL CAUSE TEMPS TO STAY RATHER
STEADY OVER MUCH OF THE AREA...AND EVEN DROP A FEW DEGS IN THE
NWRN THIRD OF THE AREA.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH SUNDAY/...
GFS AND NAM KEEP THE SRN STREAM SYSTEM ROLLING TO THE EAST AND
NEVER REALLY THREATEN OUR SERN COS WITH PRECIP. ECMWF AND ONE OR
TWO MEMBERS OF THE GEFS STILL NUDGE VERY LIGHT PRECIP INTO THE
EXTREME SE...WHICH IS JUST ENOUGH TO KEEP A 20 POP THERE FOR THE
EVENING. BUT THEN THE WAVE DEEPENS OFF SHORE AND PULLS IN THE COLD
AIR FOR FRIDAY. CLEARING IS POSSIBLE ON FRIDAY AS THE ADVECTION
CHANGES SIGN IN THE AFTN...RAISING THE 8H TEMPS 10C IN JUST
3-4HRS. THE NW FLOW ALOFT KEEPS IT ACTIVE AND UNSETTLED THROUGH
THE PERIOD. THE 1035MB HIGH OFF TO OUR SOUTH AND 8H TEMPS RISING
INTO THE BLACK ON SAT WILL MAKE IT VERY LIKELY THAT WE WILL
ECLIPSE NORMAL MAXES BY 5 TO 10F ON SAT.
THE MOST INTERESTING PERIOD OF THE ENTIRE FORECAST IS SAT NIGHT
AND SUNDAY MORNING. TIMING OF A VERY STRONG/RAPID CHANGE IN AIR
MASS IS FAIRLY CONSISTENT AMONG THE NUMERICAL GUIDANCE. THE FRONT
WILL BLOW THROUGH SOMETIME AROUND OR AFTER MIDNIGHT IN THE NW AND
SHORTLY AFTER SUNRISE IN THE SE. THIS SORT OF SET UP IS VERY
FAVORABLE FOR INTENSE SNOW SHOWERS/SQUALLS. HOWEVER...THE
EXPECTED NIGHTTIME PASSAGE COULD LESSEN THE INTENSITY OF ANY
SQUALLS WITHOUT THE MODEST INCREASE IN INSTABILITY/MIXING POSSIBLE
DURING THE DAYLIGHT HOURS. ANOTHER POSITIVE THING IS THAT IT
SHOULD OCCUR IN THE OVERNIGHT AND NOT EVEN ON A SCHOOL/WORK-DAY
MORNING. HAVE CONTINUED THE MENTION OF THE POSSIBILITY OF SQUALLS
IN THE HWO...DUE TO THE POTENTIAL TRAVEL IMPACT RATHER THAN ANY
HARD AND FAST SNOW OR ICE CRITERIA. TEMPS DROP BACK ON SUNDAY TO
5 OR 10F BELOW NORMALS. HAVE ALLOWED FOR JUST A FEW DEG RISE IN
TEMPS...BUT IT COULD BE ANOTHER STEADY OR SLIGHT DROP DURING THE
DAYLIGHT HRS.
&&
.LONG TERM /SUNDAY NIGHT THROUGH WEDNESDAY/...
THE PATTERN LOOKS COLD HEADING INTO NEXT WEEK WITH HIGH
CONFIDENCE IN BELOW NORMAL TEMPERATURES. ASIDE FROM OCNL LAKE
EFFECT SNOW SHOWERS AND SCT FLURRIES...PRECIPITATION SHOULD BE
HARD TO COME BY WITH VERY DRY MODIFIED ARCTIC AIR PERSISTING THRU
THE END OF THE PD.
&&
.AVIATION /12Z THURSDAY THROUGH MONDAY/...
A SURGE OF HIGHER MOISTURE AHEAD OF APPROACHING COLD FRONT WILL
ASCEND THE W MTNS...PRODUCING A PERIOD OF IFR CIGS AT BFD AND JST
EARLY THIS AM. ACROSS THE RIDGE/VALLEY REGION...MVFR CIGS BEING
REPORTED AT AOO/UNV/IPT AT 11Z.
COLD FRONT WILL PUSH THRU CENTRAL PA LATER THIS MORNING...USHERING
IN A DRIER AIR MASS AND RISING CIGS. LATEST RAP LOW LVL MOISTURE
FIELDS SUGGEST BFD WILL RISE TO MVFR CIGS BTWN 12Z-13Z AND JST
WILL FOLLOW BY ARND 14Z. IN THE WAKE OF THE FRONT...MOISTURE FROM
LK ERIE WILL ASCEND THE NW MTNS...LIKELY RESULTING IN MVFR CIGS
PERSISTING AT BFD UNTIL AT LEAST MID AFTN. FURTHER
SOUTH...SOUNDINGS SUGGEST THE POSSIBILITY OF LINGERING MVFR CIGS
AT JST/UNV/AOO THRU ARND MIDDAY. HOWEVER...DOWNSLOPING FLOW ACROSS
THE SUSQ VALLEY SHOULD ENSURE VFR CONDS AT MDT AND LNS THROUGH
TODAY.
OUTLOOK...
FRI...AM -SHSN/MVFR CIGS POSS W MTNS.
SAT...NO SIG WX EXPECTED.
SUN-MON...SHSN/MVFR POSS W MTNS.
&&
.CTP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...DANGELO
NEAR TERM...DANGELO
SHORT TERM...DANGELO
LONG TERM...STEINBUGL
AVIATION...FITZGERALD
AREA FORECAST DISCUSSION FOR SOUTHEAST SD/SOUTHWEST MN/NORTHWEST IA
NWS SIOUX FALLS SD
955 AM CST THU JAN 17 2013
.DISCUSSION.../ISSUED AT 955 AM CST/
A COUPLE AREAS OF CLOUDS ACROSS THE CWA AT THIS TIME...WITH A SMALL
WINDOW OF CLEARING FROM SIOUX FALLS TO MARSHALL. THINK THIS AREA
WILL GIVE WAY TO INCREASING CLOUDS...AS STRATUS IN CENTRAL SOUTH
DAKOTA MOVES BACK IN. MEANWHILE...THERE IS A SECOND AREA OF LOWER
CLOUDS CLOSER TO THE MISSOURI RIVER...FROM YANKTON TO SIOUX CITY
AND SOUTH DOWN INTERSTATE 29 TOWARDS OMAHA AND LINCOLN NEBRASKA.
WILL HAVE TO WATCH AND SEE WHAT HAPPENS WITH THIS THROUGH THE REST
OF THE MORNING. RAP SUGGESTS IT MAY ACTUALLY EXPAND...AND WITH
BOUNDARY LAYER FLOW BECOMING WEAK SOUTHWESTERLY...IT MAY LINGER
ACROSS OUR NORTHWEST IOWA COUNTIES. AS FAR AS TEMPERATURES
GO...WOULD NOT BE SURPRISED IF AREAS FROM WEST OF YANKTON TO GREGORY
END UP A COUPLE DEGREES WARMER...ESPECIALLY IF IT REMAINS MOSTLY
SUNNY. ALSO...AREAS FROM SIOUX FALLS TO SIOUX CITY AND EAST...MAY
END UP A FEW DEGREES COOLER THAN CURRENT FORECAST IF CLOUDS HANG
AROUND LIKE THE RAP IS SUGGESTING. GIVEN CLOUD COVER
UNCERTAINTY...WILL LEAVE HIGHS ALONE FOR NOW AND ADJUST AS NEED BE
AS CLOUD AND TEMPERATURE TRENDS BECOME MORE APPARENT LATER THIS
MORNING. /CHENARD
.PREVIOUS DISCUSSION.../ISSUED AT 305 AM CST/
A CHILLY START TO THE DAY AS A SHALLOW ARCTIC AIR MASS HAS STALLED
OVER THE EASTERN HALF OF THE CWA. THIS WILL MODIFY THROUGH THE DAY
LEADING TOWARDS HIGH TEMPERATURES A BIT ABOVE NORMAL...BUT NOT AS
WARM AS YESTERDAY. CLOUDS AS WELL AS THE COOLER START WILL BE THE
MAIN REASONS. REGARDLESS...PLANNING ON HIGHS FROM NEAR 40 ALONG THE
MISSOURI RIVER TO THE MID 20S IN SOUTHWEST MINNESOTA.
A STRONG SOUTHERLY PRESSURE GRADIENT WILL DEVELOP OVERNIGHT LEADING
TOWARDS A NON DIURNAL TEMPERATURE PROFILE. LOWS IN MOST SPOTS WILL
OCCUR BETWEEN ABOUT 2Z AND 6Z...THEN RISE AFTER. EXPECTING LOWS IN
THE MID TEENS TO LOWER 20S BUT 12Z FRIDAY TEMPERATURES LIKELY TO BE
BETWEEN 25 AND 30 DEGREES IN MOST LOCATIONS WITH A BIT OF A BREEZY
SOUTH WIND.
THIS WILL LEAD INTO A VERY WARM FRIDAY...ESPECIALLY LOOKING AT WHAT
HAPPENED ACROSS THE AREA TODAY. NOT MUCH INT HE WAY OF CLOUD COVER
AND WINDS TURNING FROM THE SOUTHWEST TO THE WEST AND NORTHWEST
THROUGH THE DAY SUPPORTS MIXY AND MILD CONDITIONS. WITH 925MB
TEMPERATURES WELL INTO THE SINGLE DIGITS...ESPECIALLY SOUTH...HIGHS
SHOULD RANGE FROM THE LOWER 40S NORTH TO 50 TO 55 SOUTH.
MILD WESTERLY FLOW WILL REMAIN IN PLACE THROUGH FRIDAY NIGHT INTO
SATURDAY MORNING AHEAD OF A STRONG PUSH OF COLD AIR. TEMPERATURES
SHOULD ONLY FALL INTO THE 20 TO 25 DEGREE RANGE FRIDAY NIGHT THEN
QUICKLY WARM INTO THE MID 30S TO LOWER 40S ON SATURDAY AHEAD OF THE
COLD FRONT. IF THE FRONT IS JUST A FEW HOURS SLOWER HIGHS WILL
LIKELY BE ANOTHER 5 DEGREES WARMER SO TIMING OF THIS BOUNDARY WILL
BE VERY IMPORTANT. HAVE TEMPERATURES TANKING LATE AFTERNOON AND
EVENING AS THE FRONT BARRELS THROUGH. AT SOME POINT IN TIME MAY NEED
A WIND ADVISORY FOR THE AREA AND POSSIBLY A WIND CHILL ADVISORY IN
THE NORTHERN CWA.
IN THE LATTER PERIODS(SUN/THU)...NOT MUCH IN THE WAY OF CHANGES AS
BELOW NORMAL TEMPERATURES STILL THE MAIN ISSUE. A VERY STRONG RIDGE
WILL BE IN PLACE OVER THE WESTERN UNITED STATES WHICH WILL ALLOW A
NORTHERLY ORIENTED JET TO BE IN PLACE OVER THE NORTHERN PLAINS. THIS
WILL MAKE IT DIFFICULT TO BREAK OUT OF THE COLD AIR DURING THE
PERIOD. WILL CONTINUE THE CHANCE FOR SNOW ON SUNDAY AHEAD OF THE
VERY STRONG COLD FRONT. NOT EXPECTING A LOT OF ACCUMULATION BUT
MIGHT BE ENOUGH TO ADD A LITTLE TO WHAT IS OUT THERE. SUNDAY NIGHT
INTO MONDAY EVENING LIKELY TO BE THE COLDEST 24 HOUR PERIOD THIS
SEASON SO FAR WITH SOME TYPE OF COLD HEADLINE ANTICIPATED. AFTER
THIS MODELS NOT REAL AGREEABLE BUT NOT TERRIBLE. LOOKS LIKE A SLOW
MODERATING TREND THROUGH THE WEEK. /08
&&
.AVIATION.../FOR THE 12Z TAF ISSUANCE/
APPEARS TO BE MANY CLOUD LAYERS AT VARYING HEIGHTS ACROSS THE REGION
AT THE START OF THE PERIOD. PRIMARY TO AVIATION CONCERNS IS IFR-LIFR
BAND OF STRATUS WITHIN SURFACE RIDGE AXIS FROM THE LOWER JAMES RIVER
VALLEY INTO NORTHEAST NEBRASKA. DIFFICULT TO DISCERN THIS BAND FROM
PRIMARILY VFR STRATUS FARTHER TO THE EAST...HOWEVER NAM/RAP MODELS
DO SHOW THIS VERY LOW LEVEL MOISTURE BAND MOVING TOWARD THE KSUX TAF
SITE BY MID-LATE MORNING. CONFIDENCE IS LOW THAT THE BAND WILL HOLD
TOGETHER/REACH KSUX...SO JUST WENT WITH MENTION OF SCATTERED CLOUD
LAYER BELOW 1KFT FOR NOW...BUT WILL WATCH CLOSELY THROUGH THE EARLY
PART OF THE PERIOD TO SEE IF BAND HOLDS TOGETHER. SOME MVFR STRATUS
CEILINGS SLIDING THROUGH NORTHEAST PARTS OF THE FORECAST AREA AS
WELL THIS MORNING...BUT NOT EXPECTED TO AFFECT TAF SITES AT THIS
TIME. BY 18Z...VFR CONDITIONS EXPECTED TO DOMINATE ACROSS THE AREA
WITH LIGHT/VARIABLE WINDS. NAM/RAP MODELS HINTING AT IFR-LIFR
STRATUS AND/OR FOG REDEVELOPING OVERNIGHT...POTENTIALLY AFFECTING
KFSD/KSUX AFTER 04Z IN ADVANCE OF SURFACE WARM FRONT. AGAIN HAVE
LOW CONFIDENCE IN THIS DEVELOPMENT AS MOISTURE LAYER APPEARS TO BE
SHALLOW ON FORECAST SOUNDINGS...SO HAVE LEFT TAFS VFR THROUGH THE
NIGHT FOR NOW.
&&
.FSD WATCHES/WARNINGS/ADVISORIES...
SD...NONE.
MN...NONE.
IA...NONE.
NE...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS ALBANY NY
434 PM EST THU JAN 17 2013
.SYNOPSIS...
A COLD FRONT WILL SETTLE SOUTH OF THE REGION TONIGHT. A STORM
SYSTEM PASSING WELL OFF THE MID ATLANTIC COAST WILL BRING SOME
CLOUDS TO THE REGION THIS EVENING...AND PERHAPS A FEW SNOW SHOWERS
OR FLURRIES FOR SOUTHEAST AREAS. HIGH PRESSURE WILL BUILD IN FOR
FRIDAY...BRINGING FAIR BUT COLD CONDITIONS. ANOTHER STORM SYSTEM
WILL APPROACH FROM THE GREAT LAKES FRIDAY NIGHT AND
SATURDAY...BRINGING CLOUDS AND SOME SNOW SHOWERS...AND FOLLOWED BY
ANOTHER SURGE OF VERY COLD AIR FOR SUNDAY THROUGH EARLY NEXT WEEK.
&&
.NEAR TERM /UNTIL 6 AM FRIDAY MORNING/...
AS OF 430 PM EST...A COLD FRONT CONTINUES TO SETTLE SOUTHWARD
ACROSS THE REGION...AND IS CURRENTLY APPROACHING THE SE CATSKILLS
INTO THE MID HUDSON VALLEY REGION. LITTLE IN THE WAY OF
PRECIPITATION IS ASSOCIATED WITH THIS FRONT AT THIS TIME.
MEANWHILE...TEMPS ARE GRADUALLY FALLING INTO THE TEENS ACROSS THE
SOUTHERN ADIRONDACKS...AND THROUGH THE 20S FOR AREAS NORTH OF THE
MOHAWK RIVER VALLEY AND CAPITAL DISTRICT.
A THICK CANOPY OF HIGH AND MID LEVEL CLOUDS CONTINUES TO COVER
MOST OF THE REGION...IN ASSOCIATION WITH MOISTURE STREAMING
NORTHWARD IN ASSOCIATION WITH THE STRONG UPPER LEVEL STORM SYSTEM
TRAVERSING THE SOUTHEAST STATES. IN ADDITION...SOME LOWER CLOUDS
CONTINUE TO AFFECT AREAS FURTHER N AND W IN ASSOCIATION WITH LOW
LEVEL COLD ADVECTION...AND SOME ADDITIONAL MOISTURE CONTRIBUTED
FROM THE GREAT LAKES.
THE LATEST HRRR INDICATES THAT AS THE MID LEVEL CLOUDS THICKEN
MORE THIS EVENING...THERE COULD BE SOME FEEDER/SEEDER PROCESSES
WITH THE LOWER CLOUD DECK WHICH COULD PRODUCE SOME LIGHT SNOW
SHOWERS OR FLURRIES FOR AREAS MAINLY SOUTH AND SOUTHEAST OF THE
GREATER CAPITAL DISTRICT...PARTICULARLY ACROSS PORTIONS OF THE
MID HUDSON VALLEY...EXTREME SOUTHERN BERKSHIRES...AND NW CT. HAVE
INCLUDED MENTION OF FLURRIES OVERNIGHT IN MOST OF THESE
AREAS...ALONG WITH MENTION OF SLIGHT CHC POPS FOR SNOW SHOWERS
ACROSS THE MID HUDSON VALLEY AND NW CT. IN THIS REGION...CAN NOT
COMPLETELY RULE OUT A COATING OF SNOW IN SOME AREAS BY DAYBREAK.
THE HIGH/MID LEVEL CLOUD CANOPY SHOULD GRADUALLY THIN FROM NW TO
SE...STARTING AROUND MIDNIGHT...AND CONTINUING THROUGH DAYBREAK.
THIS RAISES A RATHER CHALLENGING TEMPERATURE FORECAST...ESP FOR
NORTHERN AREAS...AS ANY PERIOD OF CLEAR SKIES ALONG WITH
DECREASING WIND AND AT LEAST SOME SNOW COVER COULD LEAD TO A QUICK
DROP IN TEMPS. HAVE SIDED WITH...OR EVEN WENT A BIT BELOW THE
COLDER MOS FOR MIN TEMPS OVERNIGHT ACROSS NORTHERN AREAS...WITH
WIDESPREAD SUBZERO MINS EXPECTED. FURTHER SOUTH...HAVE SIDED WITH
THE COLDER MET MOS IN MOST AREAS...ALTHOUGH TOOK A BLEND OF THE
MAV/MET MOS ACROSS SOUTHERN AREAS WHERE CLOUDS COULD LAST LONGER.
ACROSS NORTHERN AREAS WHERE SUBZERO TEMPS ARE EXPECTED...WINDS
SHOULD DROP TO BELOW 5 MPH...AND THEREFORE NO WIND CHILL HEADLINES
ARE INDICATED.
&&
.SHORT TERM /6 AM FRIDAY MORNING THROUGH SATURDAY NIGHT/...
FRIDAY...A PERIOD OF MOSTLY SUNNY SKIES IS EXPECTED THROUGH MUCH
OF THE DAY IN VALLEY AREAS...BEFORE A COMBINATION OF WARM
ADVECTION...AND SOME LAKE MOISTURE WITH A BACKING NORTHWEST TO
WEST WIND ALLOW CLOUDS TO REDEVELOP LATER IN THE DAY ACROSS THE
WESTERN MOHAWK VALLEY/ADIRONDACKS...AND PERHAPS ACROSS THE
SCHOHARIE VALLEY/HELDERBERGS. HAVE SIDED WITH THE COLDER SIDE OF
MOS FOR MAX TEMPS...WITH GENERALLY 20-25 IN VALLEY AREAS FROM
ALBANY N AND W...AND 25-30 IN VALLEY AREAS SOUTH OF ALBANY...WHILE
MOST HIGHER ELEVATIONS ONLY REACH THE TEENS. SOME SNOW SHOWERS ARE
EXPECTED TO DEVELOP BY AFTERNOON ACROSS THE WESTERN ADIRONDACKS
AND MOHAWK VALLEY REGION.
FRIDAY NIGHT-SAT...AS A STRONG CLIPPER TYPE SYSTEM APPROACHES FROM
THE GREAT LAKES REGION...A SURGE OF MID LEVEL WARM ADVECTION IS
EXPECTED TO PRODUCE ABUNDANT CLOUDS FOR LATER FRI NIGHT INTO AT
LEAST SAT MORNING...AND PERHAPS WELL INTO SAT AFTERNOON ACROSS
NORTHERN AREAS...WHERE ISENTROPIC LIFT WILL PERSIST. ALSO...AREAS
OF SNOW SHOWERS AND FLURRIES WILL OCCUR IN NORTHERN AREAS FRI NT
INTO SAT AM. SOME COATINGS WILL BE POSSIBLE IN VALLEY AREAS NORTH
OF THE CAPITAL REGION...WITH PERHAPS 1-4 INCHES ACROSS PORTIONS OF
THE WESTERN MOHAWK VALLEY/ADIRONDACK REGION. TEMPS FRI NT SHOULD
INITIALLY FALL QUICKLY...BEFORE RISING LATER IN THE EVENING
THROUGH DAYBREAK SAT. HAVE GENERALLY WENT WITH THE COLDER SIDE OF
GUIDANCE FOR MINS...ESP ACROSS NORTHERN AREAS. ON SAT...DESPITE A
DEVELOPING SOUTHWEST FLOW...CLOUDS AND A LOW LEVEL INVERSION MAY
PREVENT TEMPS FROM RISING TO THE WARMER MAV MOS NUMBERS. HAVE
SIDED WITH THE COOLER MET MOS IN MOST AREAS...AND HAVE EVEN
UNDERCUT BY A FEW ACROSS NORTHERN AREAS...WITH MID 30S EXPECTED
ACROSS THE SOUTHERN ADIRONDACKS AND LAKE GEORGE/SARATOGA
REGION...AND UPPER 30S TO LOWER 40S IN VALLEY AREAS FURTHER SOUTH.
HOWEVER...ACROSS PORTIONS OF THE SE CATSKILLS AND MID HUDSON
VALLEY...MORE SUNSHINE...AND A GUSTY DOWNSLOPING SW FLOW SHOULD
BOOST TEMPS INTO THE 45-50 RANGE.
SAT NT...OUR REGION SHOULD REMAIN WITHIN THE WARM SECTOR OF THE
APPROACHING CLIPPER. AS A COLD FRONT APPROACHES FROM THE NORTHWEST
LATER AT NIGHT...CLOUDS AND SOME SNOW SHOWERS SHOULD DEVELOP BY
DAYBREAK SUNDAY ACROSS N/W AREAS...WHERE CHC POPS ARE INDICATED.
INCREASING CLOUDS...AND A BRISK S/SW WIND SHOULD PREVENT TEMPS
FROM FALLING MUCH...AND THEREFORE HAVE GONE ABOVE MOS...WITH UPPER
20S TO MID 30S EXPECTED REGIONWIDE FOR MINS.
&&
.LONG TERM /SUNDAY THROUGH THURSDAY/...
...BELOW NORMAL TEMPERATURES WILL PERSIST THROUGH THE EXTENDED
PERIOD.
NORMAL TEMPERATURES FOR THE PERIOD JAN 20TH THROUGH 23RD:
ALBANY: HIGHS AROUND 30. LOWS IN THE MID TEENS.
GLENS FALLS: HIGHS IN THE UPPER 20S. LOWS IN THE SINGLE DIGITS.
POUGHKEEPSIE: HIGHS IN THE MID 30S. LOWS IN THE MID TEENS.
BENNINGTON: HIGHS AROUND 30. LOWS NEAR 10.
PITTSFIELD: HIGHS IN THE UPPER 20S. LOWS NEAR 10.
MODEL GUIDANCE CONTINUES TO BE IN GOOD AGREEMENT IN REGARDS TO THE
LONGWAVE PATTERN FOR THE PERIOD WITH A LARGE TROUGH COVERING THE
EASTERN 2/3 OF THE CONUS WITH SHORT WAVES ROTATING ABOUT AN UPPER
LOW OVER HUDSON/S BAY CANADA AND RIDGING ALONG THE WEST COAST.
NOW...EVEN THE DIFFERENCES IN THE LONG RANGE MODELS WERE IN PRETTY
GOOD AGREEMENT.
A POTENT CLIPPER...TRACKING ACROSS THE GREAT LAKES...WILL DRIVE AN
ARCTIC FRONT ACROSS THE REGION ON SUNDAY. THIS FRONT STILL LOOKS TO
HAVE DECENT UPPER LEVEL DYNAMICS AND A SHARP THERMAL GRADIENT
ASSOCIATED WITH IT...SO A ROUND OF SNOW SHOWERS/SQUALLS IS POSSIBLE
WITH THE FRONTAL PASSAGE. A SOUTH OR SOUTHWEST WIND WILL SHIFT
WEST-NORTHWEST AND DRIVE H850 TEMPS FROM ABOUT -2C EARLY...TO NEARLY
-20C BY LATE IN THE DAY! TEMPERATURES MIGHT ACTUALLY SPIKE IN THE
MORNING...THEN DROP DURING THE AFTERNOON ACROSS THE ENTIRE REGION.
HOWEVER THIS FAR OUT...WE JUST USED THE CLIMATOLOGICAL DIURNAL TREND
IN THE GRIDS SINCE A CHANGE IN THE ARRIVAL OF THIS REALLY COLD AIR
WOULD CHANGE HOURLY TEMPERATURES QUITE A BIT.
BY SUNDAY NIGHT WITH 850 MB TEMPERATURES LOOK TO HAVE DROPPED TO
BETWEEN -15 TO -20 C ACROSS THE FORECAST AREA. A WESTERLY WIND OF 10
TO 20 MPH WILL MAKE IT FEEL EVEN COLDER. WIND CHILL VALUES MAY REACH
ADVISORY CRITERIA (-20F) ACROSS THE SOUTHERN ADIRONDACKS AND THE
HIGHER TERRAIN OF SOUTHERN VERMONT. WILL HAVE MENTION IN OUR
HAZARDOUS WEATHER OUTLOOK.
SHORT WAVES ROTATING ABOUT THE UPPER LOW WILL BRING REINFORCING
SHOTS OF COLDER AIR TO THE REGION AS ADDITIONAL CLIPPER SYSTEMS MOVE
THROUGH MONDAY THROUGH WEDNESDAY. THIS WILL KEEP CLOUDS AND THE
THREAT OF SNOW SHOWERS IN THE FORECAST...ESPECIALLY DOWNWIND OF LAKE
ONTARIO. AT THIS POINT THE SYSTEMS WILL HAVE LIMITED MOISTURE
ASSOCIATED WITH THEM SO ANY PRECIPITATION/SNOW SHOULD BE LIGHT.
ONE THING TO WATCH ON TUESDAY. IT STILL APPEARS THAT A STORM IN THE
SOUTHERN JETSTREAM SHOULD MOVE WELL SOUTH AND EAST OF OUR REGION OUT
INTO THE OCEAN. HOWEVER...EVEN IF IT DOES...INTERACTION BETWEEN THIS
SYSTEM AND A POSSIBLE SHORTWAVE REINFORCING THE TROUGH OVER
US...MIGHT PRODUCE BROAD ASCENT TO GIVE OUR ENTIRE AREA LIGHT SNOW
OR SNOW SHOWERS TUESDAY. AGAIN...THIS SCENARIO IS NOT ETCHED IN
STONE...AND FOR NOW...ONLY WENT SLIGHT CHANCES IN AREAS OUTSIDE THE
ELEVATED TERRAIN TO THE WEST OF THE HUDSON VALLEY WHERE WE WENT LOW
POPS DUE TO MORE LAKE AVAILABLE EFFECT MOISTURE.
AS THE AFOREMENTIONED OCEAN STORM WINDS UP LATE TUESDAY...IT LOOKS
TO DRIVE ANOTHER SURGE OF ARCTIC AIR OUR WAY FOR TUESDAY...WITH SOME
INDICATIONS THAT H850 TEMPERATURES COULD BE EVEN COLDER (IN THE -20C
TO -25C RANGE). OF COURSE THIS NEW SURGE OF ARCTIC AIR COULD COME
WITH ANOTHER ROUND OF SNOW SHOWERS/SNOW SQUALLS AND LAKE EFFECT
SNOW.
INITIALLY THE ENVIRONMENT LOOKS SOMEWHAT SHEARED FOR SIGNIFICANT
LAKE EFFECT ACCUMULATIONS. HOWEVER...BY LATE TUESDAY INTO
WEDNESDAY...THE FLOW LOOKS TO BECOME MORE CYCLONIC WITH LESS SHEAR
AND VERY COLD AIR PRODUCING POTENTIAL EXTREME SLANTWISE INSTABILITY
OFF LAKE ONTARIO. WE WILL MONITOR THE LAKE EFFECT POTENTIAL THROUGH
THE PERIOD.
TEMPERATURES WILL TO TOP OUT IN THE 30S TO NEAR 40 SUNDAY IN THE
HUDSON VALLEY (THE WARMEST READINGS AROUND POUGHKEEPSIE). HIGHER
TERRAIN WILL SEE HIGHS ONLY 25-30. AGAIN...TEMPERATURES COULD DROP
DURING THE AFTERNOON.
OVERNIGHT LOWS SUNDAY NIGHT THROUGH WEDNESDAY LOOK TO TUMBLE TO THE
TEENS FROM THE TRI-CITIES SOUTHWARD...AROUND ZERO TO SINGLE NUMBERS
FURTHER NORTH AND WEST. THIS ASSUMES SOME WIND (AS OPPOSED TO CALM
CONDITIONS). IF THE WIND WERE TO DECOUPLE ANY OF THESE NIGHTS WITH
EVEN A PARTIALLY CLEAR SKY...OVERNIGHT LOWS COULD BE A LOT
COLDER...ESPECIALLY UP NORTH.
DAYTIME HIGHS MONDAY THROUGH THURSDAY LOOK TO LOOK TO BE 20-25 IN
THE HUDSON VALLEY FROM ALBANY SOUTHWARD...TEENS FURTHER NORTH...WITH
SOME READINGS AROUND 10 ACROSS THE ADIRONDACKS. THESE VALUES MIGHT
NOT BE COLD ENOUGH BUT AS WE GET CLOSER TO THIS TIME PERIOD...WE
WILL ADJUST THEM AS NEEDED.
&&
.AVIATION /21Z THURSDAY THROUGH TUESDAY/...
A COLD FRONT HAS PASSED KGFL...AND WILL PASS KALB EARLY IN THE
AFTERNOON....KPOU NOT UNTIL LATE AFTERNOON OR EVENING. DESPITE THE
COLD FRONTAL PASSAGE...VFR CONDITIONS WILL PREVAIL.
THE MAIN FACTOR WITH THE COLD FRONT WILL BE A WIND SHIFT FROM W TO
N. THE WIND WILL BE GUSTY AT TIMES UP TO 20 MPH...ESPECIALLY WITH
THE PASSAGE OF THE FRONT.
BROKEN VFR CIGS AT KGFL/KALB AND KPSF WILL BE IN THE 3500-4000 FEET
AGL UNTIL EARLY EVENING. AT KPOU...MOST CLOUDS WILL NOT BE
"SENSIBLE" (OVER 12,000 FEET).
TONIGHT...MOST IF NOT ALL OF THE SENSIBLE CLOUDS WILL BE GONE. THE
ONLY EXCEPTION IS SOME VFR CIGS AROUND 4000 FEET MIGHT APPROACH KGFL
FROM MOISTURE OF LAKE CHAMPLAIN AT TIMES THROUGH EARLY FRIDAY.
A NORTH WIND WILL CONTINUE AROUND 10KTS THROUGH EARLY
TOMORROW...BECOMING LIGHTER AND MORE VARIABLE BY LATE IN THE DAY.
OUTLOOK...
FRI-SAT...VFR...NO SIG WX.
SUN...MAINLY VFR. CHC -SHSN.
MON...VFR. SLIGHT CHC -SHSN.
TUE...VFR. CHC SUB-VFR CIG -SHSN.
&&
.HYDROLOGY...
MAINLY DRY AND COLD WEATHER WILL OCCUR OVER THE NEXT FIVE DAYS.
WHILE SOME SNOW SHOWERS ARE POSSIBLE OVER THE NEXT FEW DAYS ACROSS
NORTHERN AREAS...PRECIPITATION AMOUNTS WILL BE LIGHT AND IN THE
FORM OF SNOW. COLD TEMPERATURES...ESPECIALLY EARLY NEXT
WEEK...WILL CAUSE RIVER AND LAKE ICE TO FORM AND THICKEN.
FOR DETAILS ON SPECIFIC AREA RIVERS AND LAKES...INCLUDING
OBSERVED AND FORECAST RIVER STAGES AND LAKE ELEVATIONS...PLEASE
VISIT THE ADVANCED HYDROLOGIC PREDICTION SERVICE /AHPS/ GRAPHS ON
OUR WEBSITE.
&&
.ALY WATCHES/WARNINGS/ADVISORIES...
CT...NONE.
NY...NONE.
MA...NONE.
VT...NONE.
&&
$$
SYNOPSIS...KL/HWJIV/FRUGIS
NEAR TERM...KL
SHORT TERM...KL
LONG TERM...HWJIV/IAA
AVIATION...HWJIV
HYDROLOGY...KL/FRUGIS
AREA FORECAST DISCUSSION...UPDATED
NWS DULUTH MN
1122 AM CST THU JAN 17 2013
.AVIATION...18Z TAF ISSUANCE...
MVFR CLOUD DECK IN PLACE ACROSS THE NORTHLAND THIS MORNING WILL
SLOWLY DISSIPATE THROUGH THE AFTERNOON FROM NORTH TO SOUTH. A FEW
LINGERING LIGHT SNOW SHOWERS OR FLURRIES WILL EVENTUALLY COME TO
AN END BY MID AFTERNOON. THE NEXT SYSTEM WILL MOVE IN QUICKLY FROM
THE SW TONIGHT AND SPREAD LOW-END MVFR/IFR CIGS AND IFR VSBYS IN
-SN ACROSS THE REGION. W/NW WINDS TODAY WILL SHIFT TO THE SOUTH
TONIGHT...AROUND 5-10 KT.
&&
.PREV DISCUSSION... /ISSUED 1007 AM CST THU JAN 17 2013/
UPDATE...
MADE UPDATES TO THE FORECAST THROUGH TONIGHT. THIS WAS TO INCREASE
CLOUD COVER TODAY. IT SHOULD TAKE SOME TIME FOR THE CLOUDY SKIES
ACROSS THE NORTHLAND TO MOVE EAST AND/OR DISSIPATE...BUT GENERALLY
THERE SHOULD BE DECREASING CLOUD COVER THIS AFTERNOON FROM WEST TO
EAST. ALSO...THERE WAS NOT A MENTION OF FLURRIES FOR MOST OF THE
NORTHLAND...YET THESE LOW CLOUDS ARE PRODUCING FLURRIES HERE AND
THERE. THEREFORE...ADDED FLURRIES FOR MOST OF THE NORTHLAND
THROUGH THE FIRST HALF OF THE AFTERNOON. CANCELLED THE WIND CHILL
ADVISORY FOR NORTHERN ST. LOUIS COUNTY...KOOCHICHING COUNTY...AND
THE SOUTHERN PART OF THE NORTH SHORE SINCE THE WIND CHILL VALUES
HAVE IMPROVED WITH THE INCREASING TEMPERATURES. ALSO MADE CHANGES
TO THE FORECAST FOR TONIGHT TO BETTER TIME THE LIKELY SNOW THAT
WILL MOVE INTO THE FA WITH THE WARM AIR ADVECTION ALOFT.
PREV DISCUSSION... /ISSUED 554 AM CST THU JAN 17 2013/
AVIATION...12Z TAFS
CEILINGS FROM 3500-5000FEET COVERED MUCH OF THE NORTHLAND THIS
MORNING...WITH MVFR CEILINGS AND LIGHT SNOW MOVING TOWARD KBRD.
THESE LOWER CEILINGS ARE FORECAST BY THE RAP TO AFFECT
KHIB/KDLH/KHYR LATER TODAY...AND WE PUT THEM IN THE LATEST TAF.
CLOUDS WILL DIMINISH LATER THIS AFTERNOON/EARLY EVENING...BEFORE
INCREASING AGAIN OVERNIGHT IN AN AREA OF WAA. SOME LIGHT SNOW MAY
ALSO DEVELOP LATE TONIGHT.
PREV DISCUSSION... /ISSUED 410 AM CST THU JAN 17 2013/
SHORT TERM...TODAY THROUGH FRIDAY.
AT 4 AM...CLOUDS WERE ON THE INCREASE ACROSS THE CWA. THE RESULT
WAS A BIT OF IMPROVEMENT IN TEMPS AND WIND CHILL READINGS. HAVE
REMOVED ITASCA COUNTY...AND THE DULUTH AND SUPERIOR AREAS FROM THE
WIND CHILL ADVISORY...AS WIND CHILL READINGS HAD IMPROVED A BIT.
WILL LIKELY BE ABLE TO REMOVE OTHER COUNTIES AS THE MORNING WEARS
ON DUE TO THE INCREASING CLOUDS.
THE MAIN FOCUS FOR TODAY WILL BE THE WIND CHILL READINGS THIS
MORNING...ALONG WITH CLOUD TRENDS. THERE WILL LIKELY BE SOME
DECREASE IN CLOUDS ACROSS THE CWA TODAY. THE NAM ACTUALLY PICKS UP
ON THE BAND OF CLOUDS MOVING INTO NORTHERN MN...AND IT CARRIES
THAT SHORTWAVE TO THE EAST AS THE DAY WEARS ON. HIGH TEMPS WILL
LIKELY REMAIN A BIT BELOW ZERO IN THE FAR NORTH TODAY...BUT WILL
APPROACH 10 ABOVE IN THE SOUTH.
THE MAIN FOCUS FOR TONIGHT AND FRIDAY IS THE DEVELOPING LOW
PRESSURE SYSTEM THAT IS EXPECTED TO SLIDE INTO THE LAKE SUPERIOR
REGION THROUGH THE END OF THE WEEK. HAVE INCREASED POPS
CONSIDERABLY LATER TONIGHT AND INTO FRIDAY. COULD SEE SOME 2 TO 4
INCH AMOUNTS IN THE NORTH...AND POSSIBLY EVEN 3 TO 5 ACROSS THE
ARROWHEAD. WILL ALSO NEED TO WATCH THE NORTH SHORE FOR THE
POSSIBILITY OF LOCALIZED HIGHER AMOUNTS DUE TO LAKE ENHANCEMENT.
MAY NEED TO ISSUE ADVISORIES FOR PORTIONS OF THE NORTHLAND IN
LATER FORECAST PACKAGES. TEMPERATURES WILL WARM CONSIDERABLY ON
FRIDAY...ESPECIALLY ACROSS THE SOUTH...AS THE SOUTHERN HALF OF THE
CWA SHOULD BE IN THE WARM SECTOR DURING THE DAY.
LONG TERM...FRIDAY NIGHT THROUGH WEDNESDAY.
MUCH COLDER TEMPERATURES WILL BE MOVING INTO THE NORTHLAND IN THE
EXTENDED PERIOD.
A COUPLE SHORTWAVES WILL AFFECT THE NORTHLAND FRIDAY NIGHT INTO
SATURDAY...WITH THE STRONGER WAVE/LOW OCCURRING SATURDAY. LIGHT SNOW
WILL OCCUR FRIDAY NIGHT...MAINLY NORTH WITH OVERNIGHT ACCUMULATIONS
MAINLY RANGING FROM A DUSTING TO PERHAPS AN INCH. THE STRONGER WAVE
ON SATURDAY WILL BE ACCOMPANIED BY A DEEPENING LOW AND AS THEY
PASS...MUCH COLDER AIR WILL POUR INTO THE REGION. SOME ADDITIONAL
SNOWFALL WILL OCCUR SATURDAY...AGAIN MAINLY NORTH AND AMOUNTS WILL
BE SOMEWHAT LIMITED FOR MOST AREAS. A FEW INCHES WILL BE POSSIBLE
OVER THE ARROWHEAD. WE INCREASED TEMPS FRIDAY NIGHT INTO
SATURDAY...BEFORE THE COLD AIR MOVES IN. TEMPERATURES WILL START TO
FALL LATER SATURDAY...ESPECIALLY OVER OUR MINNESOTA ZONES. STRONG
WEST-NORTHWEST WINDS WILL DEVELOP SATURDAY INTO SATURDAY NIGHT...AND
WE INCREASED THEM QUITE A BIT. A WIND CHILL ADVISORY WILL LIKELY BE
NEEDED SATURDAY NIGHT OVER OUR MINNESOTA ZONES...AND EXTREME
NORTHWEST WISCONSIN ZONES.
OUTSIDE OF AN EXTENDED PERIOD OF LAKE EFFECT OF SNOW ALONG PORTIONS
OF THE SOUTH SHORE...THE MAIN FOCUS SATURDAY NIGHT INTO WEDNESDAY
WILL BE THE COLD. LOW WILL DROP INTO THE TEENS BELOW ZERO SATURDAY
NIGHT OVER OUR NORTHERN ZONES...AND SINGLE DIGITS BELOW OVER
NORTHWEST WISCONSIN. WE HAVE TEENS TO AROUND 25 BELOW ZERO SUNDAY
NIGHT AND MONDAY NIGHT AND TEENS BELOW TUESDAY NIGHT. HIGHS SUNDAY
WILL REMAIN AT OR BELOW ZERO OVER MOST OF NORTHEAST MINNESOTA...AND
ZERO TO 5 ABOVE IN NORTHWEST WISCONSIN...AND BE A FEW DEGREES COLDER
ON MONDAY.
A FAVORABLE PERIOD OF LES WILL OCCUR SATURDAY NIGHT INTO SUNDAY
NIGHT...ALTHOUGH 850MB TEMPERATURES WILL BE VERY COLD BY SUNDAY
NIGHT WHICH MAY LIMIT SNOW ACCUMULATIONS. SOME SIGNIFICANT SNOW
ACCUMULATIONS WILL BE POSSIBLE IN THE SNOWBELT SATURDAY NIGHT INTO
SUNDAY.
&&
.POINT TEMPS/POPS...
DLH 6 -3 26 20 / 10 60 70 30
INL 0 -13 17 7 / 10 60 70 50
BRD 9 1 32 19 / 20 60 20 10
HYR 8 -2 34 17 / 30 60 60 20
ASX 9 -1 29 18 / 10 30 70 30
&&
.DLH WATCHES/WARNINGS/ADVISORIES...
MN...WIND CHILL ADVISORY UNTIL NOON CST TODAY FOR MNZ012-021.
WI...NONE.
LS...NONE.
&&
$$
AVIATION...TENTINGER
AREA FORECAST DISCUSSION...UPDATED
NWS DULUTH MN
1007 AM CST THU JAN 17 2013
.UPDATE...
MADE UPDATES TO THE FORECAST THROUGH TONIGHT. THIS WAS TO INCREASE
CLOUD COVER TODAY. IT SHOULD TAKE SOME TIME FOR THE CLOUDY SKIES
ACROSS THE NORTHLAND TO MOVE EAST AND/OR DISSIPATE...BUT GENERALLY
THERE SHOULD BE DECREASING CLOUD COVER THIS AFTERNOON FROM WEST TO
EAST. ALSO...THERE WAS NOT A MENTION OF FLURRIES FOR MOST OF THE
NORTHLAND...YET THESE LOW CLOUDS ARE PRODUCING FLURRIES HERE AND
THERE. THEREFORE...ADDED FLURRIES FOR MOST OF THE NORTHLAND
THROUGH THE FIRST HALF OF THE AFTERNOON. CANCELLED THE WIND CHILL
ADVISORY FOR NORTHERN ST. LOUIS COUNTY...KOOCHICHING COUNTY...NAD
THE SOUTHERN PART OF THE NORTH SHORE SINCE THE WIND CHILL VALUES
HAVE IMPROVED WITH THE INCREASING TEMPERATURES. ALSO MADE CHANGES
TO THE FORECAST FOR TONIGHT TO BETTER TIME THE LIKELY SNOW THAT
WILL MOVE INTO THE FA WITH THE WARM AIR ADVECTION ALOFT.
&&
.PREV DISCUSSION... /ISSUED 554 AM CST THU JAN 17 2013/
AVIATION...12Z TAFS
CEILINGS FROM 3500-5000FEET COVERED MUCH OF THE NORTHLAND THIS
MORNING...WITH MVFR CEILINGS AND LIGHT SNOW MOVING TOWARD KBRD.
THESE LOWER CEILINGS ARE FORECAST BY THE RAP TO AFFECT
KHIB/KDLH/KHYR LATER TODAY...AND WE PUT THEM IN THE LATEST TAF.
CLOUDS WILL DIMINISH LATER THIS AFTERNOON/EARLY EVENING...BEFORE
INCREASING AGAIN OVERNIGHT IN AN AREA OF WAA. SOME LIGHT SNOW MAY
ALSO DEVELOP LATE TONIGHT.
PREV DISCUSSION... /ISSUED 410 AM CST THU JAN 17 2013/
SHORT TERM...TODAY THROUGH FRIDAY.
AT 4 AM...CLOUDS WERE ON THE INCREASE ACROSS THE CWA. THE RESULT
WAS A BIT OF IMPROVEMENT IN TEMPS AND WIND CHILL READINGS. HAVE
REMOVED ITASCA COUNTY...AND THE DULUTH AND SUPERIOR AREAS FROM THE
WIND CHILL ADVISORY...AS WIND CHILL READINGS HAD IMPROVED A BIT.
WILL LIKELY BE ABLE TO REMOVE OTHER COUNTIES AS THE MORNING WEARS
ON DUE TO THE INCREASING CLOUDS.
THE MAIN FOCUS FOR TODAY WILL BE THE WIND CHILL READINGS THIS
MORNING...ALONG WITH CLOUD TRENDS. THERE WILL LIKELY BE SOME
DECREASE IN CLOUDS ACROSS THE CWA TODAY. THE NAM ACTUALLY PICKS UP
ON THE BAND OF CLOUDS MOVING INTO NORTHERN MN...AND IT CARRIES
THAT SHORTWAVE TO THE EAST AS THE DAY WEARS ON. HIGH TEMPS WILL
LIKELY REMAIN A BIT BELOW ZERO IN THE FAR NORTH TODAY...BUT WILL
APPROACH 10 ABOVE IN THE SOUTH.
THE MAIN FOCUS FOR TONIGHT AND FRIDAY IS THE DEVELOPING LOW
PRESSURE SYSTEM THAT IS EXPECTED TO SLIDE INTO THE LAKE SUPERIOR
REGION THROUGH THE END OF THE WEEK. HAVE INCREASED POPS
CONSIDERABLY LATER TONIGHT AND INTO FRIDAY. COULD SEE SOME 2 TO 4
INCH AMOUNTS IN THE NORTH...AND POSSIBLY EVEN 3 TO 5 ACROSS THE
ARROWHEAD. WILL ALSO NEED TO WATCH THE NORTH SHORE FOR THE
POSSIBILITY OF LOCALIZED HIGHER AMOUNTS DUE TO LAKE ENHANCEMENT.
MAY NEED TO ISSUE ADVISORIES FOR PORTIONS OF THE NORTHLAND IN
LATER FORECAST PACKAGES. TEMPERATURES WILL WARM CONSIDERABLY ON
FRIDAY...ESPECIALLY ACROSS THE SOUTH...AS THE SOUTHERN HALF OF THE
CWA SHOULD BE IN THE WARM SECTOR DURING THE DAY.
LONG TERM...FRIDAY NIGHT THROUGH WEDNESDAY.
MUCH COLDER TEMPERATURES WILL BE MOVING INTO THE NORTHLAND IN THE
EXTENDED PERIOD.
A COUPLE SHORTWAVES WILL AFFECT THE NORTHLAND FRIDAY NIGHT INTO
SATURDAY...WITH THE STRONGER WAVE/LOW OCCURRING SATURDAY. LIGHT SNOW
WILL OCCUR FRIDAY NIGHT...MAINLY NORTH WITH OVERNIGHT ACCUMULATIONS
MAINLY RANGING FROM A DUSTING TO PERHAPS AN INCH. THE STRONGER WAVE
ON SATURDAY WILL BE ACCOMPANIED BY A DEEPENING LOW AND AS THEY
PASS...MUCH COLDER AIR WILL POUR INTO THE REGION. SOME ADDITIONAL
SNOWFALL WILL OCCUR SATURDAY...AGAIN MAINLY NORTH AND AMOUNTS WILL
BE SOMEWHAT LIMITED FOR MOST AREAS. A FEW INCHES WILL BE POSSIBLE
OVER THE ARROWHEAD. WE INCREASED TEMPS FRIDAY NIGHT INTO
SATURDAY...BEFORE THE COLD AIR MOVES IN. TEMPERATURES WILL START TO
FALL LATER SATURDAY...ESPECIALLY OVER OUR MINNESOTA ZONES. STRONG
WEST-NORTHWEST WINDS WILL DEVELOP SATURDAY INTO SATURDAY NIGHT...AND
WE INCREASED THEM QUITE A BIT. A WIND CHILL ADVISORY WILL LIKELY BE
NEEDED SATURDAY NIGHT OVER OUR MINNESOTA ZONES...AND EXTREME
NORTHWEST WISCONSIN ZONES.
OUTSIDE OF AN EXTENDED PERIOD OF LAKE EFFECT OF SNOW ALONG PORTIONS
OF THE SOUTH SHORE...THE MAIN FOCUS SATURDAY NIGHT INTO WEDNESDAY
WILL BE THE COLD. LOW WILL DROP INTO THE TEENS BELOW ZERO SATURDAY
NIGHT OVER OUR NORTHERN ZONES...AND SINGLE DIGITS BELOW OVER
NORTHWEST WISCONSIN. WE HAVE TEENS TO AROUND 25 BELOW ZERO SUNDAY
NIGHT AND MONDAY NIGHT AND TEENS BELOW TUESDAY NIGHT. HIGHS SUNDAY
WILL REMAIN AT OR BELOW ZERO OVER MOST OF NORTHEAST MINNESOTA...AND
ZERO TO 5 ABOVE IN NORTHWEST WISCONSIN...AND BE A FEW DEGREES COLDER
ON MONDAY.
A FAVORABLE PERIOD OF LES WILL OCCUR SATURDAY NIGHT INTO SUNDAY
NIGHT...ALTHOUGH 850MB TEMPERATURES WILL BE VERY COLD BY SUNDAY
NIGHT WHICH MAY LIMIT SNOW ACCUMULATIONS. SOME SIGNIFICANT SNOW
ACCUMULATIONS WILL BE POSSIBLE IN THE SNOWBELT SATURDAY NIGHT INTO
SUNDAY.
&&
.POINT TEMPS/POPS...
DLH 6 -3 26 20 / 10 60 70 30
INL 0 -13 17 7 / 10 60 70 50
BRD 9 1 32 19 / 10 60 20 10
HYR 8 -2 34 17 / 10 60 60 20
ASX 9 -1 29 18 / 10 30 70 30
&&
.DLH WATCHES/WARNINGS/ADVISORIES...
MN...WIND CHILL ADVISORY UNTIL NOON CST TODAY FOR MNZ012-021.
WI...NONE.
LS...NONE.
&&
$$
SHORT TERM...GROCHOCINSKI
LONG TERM....TENTINGER
AREA FORECAST DISCUSSION
NWS OMAHA/VALLEY NE
333 PM CST THU JAN 17 2013
.SHORT TERM...TONIGHT THROUGH SUNDAY
MAIN FORECAST PROBLEM IS TEMPS AND WINDS WITH THE STRONG COLD
FRONT ON SATURDAY AND ANOTHER FRONT SUNDAY/SUNDAY NIGHT.
HOWEVER THE INITIAL ISSUE IS THE PERSISTENT AREA OF FOG AND
STRATUS THAT REMAINED JUST EAST OF OMAHA THROUGHOUT THE DAY...BUT
AFTERNOON VISIBLE LOOP SHOWS THAT AREA IS FINALLY ERODING WITH THE
HELP OF AFTERNOON WARMING AND A WEST COMPONENT TO THE CLOUD TOP
WINDS. AS TO WHETHER OR NOT THIS FOG/STRATUS WILL FORM AGAIN
TONIGHT...WE BELIEVE THE STRENGTHENING WESTERLY 850MB WINDS SHOULD
KEEP THE LAYER MIXED ENOUGH TO PREVENT REFORMING AND SOME WARMING
IN THE LAYER SHOULD HELP AS WELL.
ASSUMING FRIDAY STARTS WITHOUT THE STRATUS DECK...THE WESTERLY
850 WINDS WILL INFLUENCE A FAIRLY QUICK WARM UP THROUGHOUT THE
MORNING AND HIGHS SHOULD REACH THE 50S MOST AREAS. THOSE LOCATIONS
WHERE AN INCH OR MORE OF SNOW REMAINS WILL BE A FEW DEGREES
COOLER...WHICH IS MAINLY WEST AND NORTH OF LINCOLN INTO THE
FREMONT AREA.
ON FRIDAY THE MAIN UPPER JET REMAINS WELL NORTH OF THE FORECAST
AREA... HOWEVER A STRENGTHENING NORTHWEST FLOW JET MAX IS
FORECAST TO BE MOVING THROUGH SOUTHERN ALBERTA/SASKATCHEWAN WHICH
QUICKLY PUSHES ARCTIC AIR SOUTH THROUGH THE PLAINS. MODELS ARE IN
GOOD AGREEMENT WITH THE TIMING AND STRENGTH OF THE COLD FRONTAL
PASSAGE ACROSS OUR AREA SATURDAY. BEFORE THE FRONT MOVES
THROUGH ON SATURDAY...THE AIRMASS WILL AGAIN SUPPORT WARM
TEMPERATURES IN THE 40S BUT SOME CLOUD COVER WILL LIMIT WARMING.
BEHIND THE FRONT NORTHWEST WINDS WILL INCREASE CONSIDERABLY WITH
GUSTS OF 30 MPH AND SHARPLY FALLING TEMPERATURES. THE AIRMASS WILL
REMAIN TOO DRY FOR ANY PRECIPITATION WITH THIS SYSTEM.
BY SUNDAY A 1032+ SURFACE HIGH BUILDS IN WITH HIGHS MOSTLY IN THE
20S. ALSO ON SUNDAY THE UPPER RIDGE ALONG THE WEST COAST IS
PROGGED TO AMPLIFY AND THUS PUSH ANOTHER COLD FRONT THROUGH THE
PLAINS...THIS TIME FOLLOWED BY A STRONGER SURFACE HIGH OF AROUND
1040MB. NAM AND GFS ARE IN FAIR AGREEMENT ON THE TIMING OF THE
SUNDAY FRONT BUT THE 12Z ECMWF IS A BIT SLOWER. EITHER WAY WE WILL
SEE ANOTHER SURGE OF ARCTIC AIR AND COLDER TEMPERATURES. WIND
CHILLS COULD DROP INTO THE MINUS 15 TO MINUS 20 DEGREE RANGE LATE
SUNDAY NIGHT AND MONDAY MORNING ESPECIALLY IN NORTHEAST NEBRASKA.
ONE FACTOR THAT WILL HELP KEEP TEMPERATURES FROM PLUMMETING WELL BELOW
ZERO WITH THESE ARCTIC BLASTS WILL BE THE LACK OF SNOW COVER.
HOWEVER COMPARED TO THE WARM DAYS LEADING UP TO SUNDAY...THE
CHANGE IN TEMPERATURES AND WIND CHILLS WILL SURELY HAVE AN IMPACT
ON THE REGION.
NIETFELD
.LONG TERM...SUNDAY NIGHT THROUGH THURSDAY
MAIN CONCERN CONTINUES TO BE TEMPERATURES THROUGH THE PERIOD.
ARCTIC AIRMASS IS STILL PROGGED TO PUSH INTO THE AREA THIS
WEEKEND...WITH REINFORCING COLD AIR ON SUNDAY NIGHT/MONDAY. CWA
WILL BE ON THE WESTERN FRINGE OF THE COLDEST AIR...AND LACKING IN
SNOWPACK...BUT STILL COULD SEE TEMPS FALL INTO THE SINGLE DIGITS
BELOW TO SINGLE DIGITS ABOVE ZERO...WITH RECOVERY INTO THE LOWER
TEENS TO LOWER 20S ON MONDAY. MODERATING TEMPERATURES WILL THEN
CONTINUE THROUGH AT LEAST WEDNESDAY NIGHT AS UPPER-LEVEL RIDGE MOVES
OVERHEAD AND LOW-LEVEL SOUTHWEST FLOW CONTINUES. BY WEDNESDAY
NIGHT/THURSDAY...ECMWF AND GFS BOTH INDICATE A STORM SYSTEM MOVING
OUT OF THE ROCKIES AND ACROSS THE PLAINS. GFS AND 00Z ECMWF KEPT
PRECIP EAST OF THE CWA...WHILE 12Z ECMWF IS A LITTLE SLOWER AND
DEEPER AND DOES PLACE CWA IN A MORE FAVORABLE LOCATION FOR PRECIP.
FOR NOW...BLENDS WERE DRY AND BELIEVE THAT IS THE WAY TO LEAN UNTIL
MODELS DEVELOP SOME CONSISTENCY WITH THE THURSDAY SYSTEM. COLD AIR
WILL SPILL IN AGAIN BEHIND THE SYSTEM...BEGINNING SOMETIME AROUND
THURSDAY.
MAYES
&&
.AVIATION...
18Z TAFS FOR KOMA...KOFK...KLNK
INITIAL CONCERN WILL BE HOW THE STRATUS WILL AFFECT KOMA NOW THAT
IT IS MOVING OUT OF KLNK AND IS TO THE EAST OF KOFK. THE RAP SEEMS
TO BE HANDLING THE STRATUS THE BEST...ALTHOUGH MAY NOT BE
EXTENSIVE ENOUGH WITH THE WEAK FLOW. IFR CONDITIONS HAVE SPREAD
INTO MLE AND WITH THE LIGHT NORTHEAST DRIFT OF THE DECK...DID
BRING THE DECK IN KOMA THROUGH 00Z. WILL NEED TO MONITOR THIS
AFTERNOON UNTIL EARLY EVENING TO SEE HOW MUCH THE AREA IS ABLE TO
SHRINK DURING THE AFTERNOON.
AFTER 03Z...THE LOW LEVEL JET STRENGTHENS AND HAVE ADDED TO ALL
THREE TAF FORECASTS. THIS SHOULD HINDER ANY LOW CLOUDS
DEVELOPMENT.
ZAPOTOCNY
&&
.OAX WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
IA...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS OMAHA/VALLEY NE
1159 AM CST THU JAN 17 2013
.UPDATE...
WILL CONTINUE TO MAKE SHORT TERM UPDATES TO BETTER ACCOUNT FOR
STRATUS AND TEMPERATURES.
&&
.DISCUSSION...
CLOUDS AND TEMPERATURES TO BE QUITE VARIABLE TODAY. UPDATED THE
PUBLIC FORECAST TO LOWER TEMPERATURES WHERE STRATUS AND FOG WILL
HOLD ON LONGER. FLOW IS WEAK...BUT TENDENCY IS TO SHIFT EAST WITH
TIME. LOCATIONS TOWARD ALBION HAVE WARMED QUICKLY INTO THE 40S
WITH A LITTLE BETTER MIXING.
&&
.AVIATION...
18Z TAFS FOR KOMA...KOFK...KLNK
INITIAL CONCERN WILL BE HOW THE STRATUS WILL AFFECT KOMA NOW THAT
IT IS MOVING OUT OF KLNK AND IS TO THE EAST OF KOFK. THE RAP SEEMS
TO BE HANDLING THE STRATUS THE BEST...ALTHOUGH MAY NOT BE
EXTENSIVE ENOUGH WITH THE WEAK FLOW. IFR CONDITIONS HAVE SPREAD
INTO MLE AND WITH THE LIGHT NORTHEAST DRIFT OF THE DECK...DID
BRING THE DECK IN KOMA THROUGH 00Z. WILL NEED TO MONITOR THIS
AFTERNOON UNTIL EARLY EVENING TO SEE HOW MUCH THE AREA IS ABLE TO
SHRINK DURING THE AFTERNOON.
AFTER 03Z...THE LOW LEVEL JET STRENGTHENS AND HAVE ADDED TO ALL
THREE TAF FORECASTS. THIS SHOULD HINDER ANY LOW CLOUDS
DEVELOPMENT.
&&
.PREV DISCUSSION... /ISSUED 156 AM CST THU JAN 17 2013/
DISCUSSION...
IMPENDING DRY ARCTIC BLAST THIS WEEKEND CONTINUES TO BE MAIN ISSUE.
GOING FCST IS IN VERY GOOD SHAPE AND ONLY MINOR TWEAKS NEEDED.
LARGE SCALE FLOW OVER THE NEXT SEVERAL DAYS WILL MAKE POSSIBLE A
DRAMATIC SHIFT IN TEMPERATURES THIS WEEKEND AND EARLY NEXT WEEK.
MODELS IN AGREEMENT AMPLIFYING WRN CONUS UPPER LEVEL RIDGE AND
BROAD LONGWAVE TROF DOWNSTREAM WILL ALLOW THE COLDEST AIR MASS OF
THE SEASON TO DROP OUT OF CANADA AND INTO THE LOWER 48.
MODELS CONTINUE TO ADVERTISE INITIAL THRUST OF CAA WILL BE UNDERWAY
EARLY SAT MORNING IN ASSOCIATION WITH DEEP SFC LOW DROPPING DOWN THRU
THE UPPER MIDWEST. TIME-SECTIONS PRETTY MUCH SHOWING LEADING EDGE OF
THE BNDRY SHOULD BE PASSING THRU THE OMAHA METRO SHORTLY BEFORE AFTN.
SUN NIGHT/MON...REINFORCING SHOT OF INTENSE CAA IS THEN PROGGED TO
DROP INTO THE CNTRL PLAINS. AS USUAL WITH INTENSE THERMAL ADVECTION
MEX AND ECM MOS NUMBERS ARE OFF...AND IN THIS CASE TOO WARM. AT THIS
POINT STILL THINK MONDAY LOWS WILL BOTTOM OUT AROUND 5-10 ABOVE WITH
WIND CHILL INDICES RANGING -10 TO -20 BELOW WHILE HIGHS WILL STRUGGLE
TO REACH THE MID/UPPER TEENS.
FORTUNATELY...THE BITTERLY COLD CONDITIONS WILL BE SHORT LIVED AND
WITH TEMPS REBOUNDING WED/THURS WITH HIGHS GENERALLY IN THE U30S/M40S
AFOREMENTIONED WRN RIDGE BUILDING EAST AND INCREASING THKNS SPREADING
OVER THE PLAINS.
DEE
&&
.OAX WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
IA...NONE.
&&
$$
ZAPOTOCNY
AREA FORECAST DISCUSSION
NWS RALEIGH NC
255 PM EST THU JAN 17 2013
.SYNOPSIS...
STRENGTHENING LOW PRESSURE OVER UPSTATE SOUTH CAROLINA WILL TRACK TO
THE EAST NORTHEAST ACROSS SOUTHEAST NORTH CAROLINA THIS EVENING...
THEN OFF THE COAST LATE TONIGHT. COLD HIGH PRESSURE WILL BUILD IN
FROM THE WEST FRIDAY INTO THE WEEKEND.
&&
.NEAR TERM /THROUGH FRIDAY/...
AS OF 150 PM THURSDAY...
THROUGH TONIGHT: CONFIDENCE REMAINS HIGH IN THE OCCURRENCE OF
SIGNIFICANT BANDED SNOWFALL OVER NRN AND WRN PORTIONS OF NC EARLY
THIS EVENING THROUGH TONIGHT.
INTENSIFYING SURFACE LOW PRESSURE... LOCATED OVER NE GA EARLY THIS
AFTERNOON... WILL CONTINUE A STEADY ENE TRACK ALONG A FRONTAL ZONE
ACROSS SE NC. THE NAM/GFS/RAP/SREF MEAN HAVE EXHIBITED EXCELLENT
CONTINUITY THE LAST SEVERAL RUNS REGARDING TRACK AND TIMING... AND
HAVE SHOWN A VERY SMALL SOUTHWARD TREND IN THE EXTENT OF COLDER AIR.
DYNAMIC LIFT WITH THIS SYSTEM WILL BE EXTREMELY STRONG -- ESPECIALLY
ALOFT WITH HIGH OMEGA FOCUSED IN THE CRUCIAL -12C TO -20C LAYER
ALOFT -- BUT QUICK-HITTING. AN INTENSE UPPER DIVERGENCE MAX EXPECTED
TO BE ROUGHLY OVER THE SRN NC FOOTHILLS AT 00Z WILL MOVE NE THROUGH
CENTRAL NC BEFORE EXITING NE SECTIONS OF THE CWA BY AROUND 07Z. THIS
IS IN TANDEM WITH THE PASSAGE OF STRONG Q-VECTOR CONVERGENCE... MID
LEVEL DCVA AND A RISE/FALL COUPLET OF AROUND +/- 200 METERS...
STRONG LOW LEVEL THETA-E ADVECTION... AND DEEP MOIST ISENTROPIC
UPGLIDE. THE FACT THAT THIS SYSTEM IS STRENGTHENING QUICKLY UPON
ARRIVAL IS ESPECIALLY TROUBLING IN THAT THE RESULTANT RAPID MASS
FIELD ADJUSTMENTS ARE LIABLE TO SIGNIFICANT AND QUICKLY BOLSTER
ASCENT AND HEIGHTEN THE EXTENT AND INTENSITY OF THE SNOW BANDING.
MOISTURE AVAILABILITY WILL GENERALLY NOT BE A PROBLEM WITH VERY HIGH
PW (OVER 200 PERCENT OF NORMAL) AND A STRONG MOISTURE TRANSPORT FROM
THE GULF... ALTHOUGH THE INCOMING DRY SLOT ON THE SE SIDE OF THE LOW
WILL BE WORTH MONITORING AND MAY LIMIT WINTRY TOTALS IN THE
SOUTHEAST CWA (SEE BELOW). HOW FAST THE COLD AIR ARRIVES ESPECIALLY
ALOFT REMAINS A CONCERN... ALTHOUGH THE MODELS INITIALIZED WELL AND
ARE IN VERY GOOD AGREEMENT... BOOSTING CONFIDENCE IN THEIR TIMING OF
THE ANTICIPATED THERMAL CHANGES.
THE HEAVIEST SNOW BANDING IS LIKELY TO OCCUR OVER THE WRN AND NRN
PIEDMONT... FROM HIGH ROCK AND BADIN LAKES... ACROSS THE I-40 AND
HIGHWAY 64 CORRIDORS BETWEEN (AND INCLUDING) THE TRIAD AND THE
TRIANGLE... UP TO KERR LAKE AND LAKE GASTON... VERY ROUGHLY
FOLLOWING THE I-85 CORRIDOR TO THE NW... ALIGNED WITH THE AREA OF
STRONGEST DEFORMATION ALOFT. KEY TIMING STILL LOOKS TO BE FROM 23Z
UNTIL AROUND 07Z WITH A QUICK EXIT SOON THEREAFTER. SREF
PROBABILITIES HAVE BEEN VERY CONSISTENT IN SHOWING A 70+ PERCENT
CHANCE OF SNOWFALL RATES OVER ONE INCH PER HOUR ACROSS MUCH OF THE
PIEDMONT AND FAR NRN COASTAL PLAIN FROM MID EVENING UNTIL THE EARLY
OVERNIGHT HOURS. WITH THESE RATES AND THE TIMING OF A FEW HOURS OF
HEAVY BANDED SNOW (STARTING AS A RAIN/SNOW MIX)... STORM TOTAL
ACCUMULATIONS OF 2-4 INCHES IN THIS AREA WITH ISOLATED 5 INCH TOTALS
LOOK QUITE REASONABLE. BORDERING THE WARNING AREA... STILL EXPECT AN
INCH OR SO OF ACCUMULATION MAINLY ON GRASSY AREAS... WITH A LITTLE
SLUSH ON ROADS POSSIBLE.
SOUTH AND EAST OF HERE... INCLUDING FAYETTEVILLE AND CLINTON... A
QUICK BURST OF MAINLY SNOW IS POSSIBLE WITH STRONG DYNAMIC COOLING
THROUGH THE COLUMN AS THE LOW ALOFT PASSES BY... BUT THE WINDOW OF
OPPORTUNITY WILL BE VERY SHORT AS AMOUNTS/DURATION WILL BE GREATLY
LIMITED BY THE MID-UPPER LEVEL DRY SLOT ARRIVAL WITH NOTABLE DRYING
ABOVE THE -5C LEVEL... SUPPRESSING CRYSTAL GROWTH ALOFT... PLUS
BOUNDARY LAYER TEMPS SHOULD HOLD ABOVE FREEZING FOR MUCH OF THIS
EVENT... NOT DROPPING TO NEAR FREEZING UNTIL PRECIP IS NEARLY GONE.
EXPECT LIGHT ACCUMULATIONS OF A DUSTING CONFINED TO GRASSY AREAS.
A SIDE NOTE: MID LEVEL LAPSE RATE PROGS ARE QUITE INTERESTING...
INCLUDING THE 12 KM NAM WHICH INDICATES 850-500 MB VALUES OF 5.5-6.0
C/KM TRAVERSING THE CWA... JUST WNW OF THE 850 MB LOW TRACK...
PRIMARILY BETWEEN 03Z AND 06Z. AND RECENT RAP RUNS TAKE THE 700-400
MB LAPSE RATES (WHICH CAPTURES THE MIXED PHASE REGION ALOFT) UP TO
7.0 C/KM OVER THE NW PIEDMONT TOWARD MIDNIGHT. CONSIDERING THIS
POSSIBILITY FOR UPRIGHT INSTABILITY COMBINED WITH VIGOROUS DYNAMIC
LIFT... A FEW LIGHTNING STRIKES WITHIN SNOW BANDS ARE CERTAINLY
POSSIBLE... ALTHOUGH LIKELY TOO ISOLATED TO INCLUDE IN THE FORECAST
AT THIS TIME.
STRENGTHENING WINDS WILL BE AN ISSUE AS WELL WITH THE TIGHTENING
MSLP GRADIENT AS THE LOW APPROACHES. WE ARE ALREADY SEEING FREQUENT
GUSTS TO 25-40 KTS (ALTHOUGH SOME OF THIS MAY BE AUGMENTED BY A
POSSIBLE GRAVITY WAVE). EXPECT A PERIOD OF SUSTAINED WINDS OF 15-25
MPH WITH SPORADIC GUSTS TO AROUND 30 MPH FROM LATE AFTERNOON UNTIL
AROUND 1-2 AM.
TEMPS SHOULD STEADILY DROP THROUGH THE REST OF THE AFTERNOON AND
NIGHT.
FOR FRIDAY: EXPECT GENERALLY CLEAR SKIES BY DAYBREAK AS THE STORM
DEPARTS QUICKLY WITH CHILLY HIGH PRESSURE BUILDING IN FROM THE WEST.
FORECAST SOUNDINGS AND UPSTREAM CONDITIONS SUGGEST THAT TEMPS SHOULD
STRUGGLE TO RISE TOMORROW WITH STRONG COLD AIR ADVECTION IN THE
MORNING... AND THICKNESSES THAT HOLD AT OR BELOW 1305 METERS ALL DAY
(AND THIS IS EVEN TAKING INTO ACCOUNT THE SHALLOW MIXING AND THAT
THIS LAYER ENCOMPASSES THE SUBSIDENCE INVERSION ALOFT). HAVE BUMPED
HIGHS DOWN TO 36-45. WINDS SHOULD DIMINISH DURING THE AFTERNOON. -GIH
&&
.SHORT TERM /FRIDAY NIGHT THROUGH SATURDAY NIGHT/...
AS OF 240 PM THURSDAY...
A 1032MB HIGH PRESSURE WILL SETTLE OVERHEAD FRIDAY NIGHT...ALLOWING
FOR GOOD RADIATIONAL COOLING UNDER CLEAR SKIES. THERE MAY BE SOME
SHADED AREAS WHERE SNOW COVER IS ABLE TO LINGER THROUGH THE DAY
FRIDAY...WHICH MAY HELP RADIATIONAL COOLING IN A FEW SPOTS...BUT
OVERALL GUIDANCE SUPPORTS LOWS IN THE MID 20S. THE UPPER LEVEL FLOW
WILL REMAIN RELATIVELY FLAT SATURDAY WHILE THE SURFACE HIGH SHIFTS
SLIGHTLY SOUTHWARD. THE SHALLOW COOLER AIRMASS WILL ONLY SLIGHTLY
MODIFY WITH WEAK VERTICAL MIXING...LEADING TO HIGHS IN THE MID 40S
TO LOWER 50S. LOWS SATURDAY NIGHT IN THE UPPER 20S TO LOWER 30S
&&
.LONG TERM /SUNDAY THROUGH THURSDAY/...
AS OF 240 PM THURSDAY...
THE UPPER LEVEL PATTERN WILL BEGIN A SLOW AMPLIFICATION SUNDAY AS
RIDGING BUILDS OUT WEST AND A DEEP TROUGH DEVELOPS OVER THE EASTERN
US. A COLD NORTHWESTERLY FLOW WILL PERSIST THROUGH MIDWEEK... A
COUPLE REINFORCING SHOTS OF ARCTIC AIR VIA DRY COLD FRONTS AS
SHORTWAVES ROTATE SOUTHEAST OUT OF CANADA AND INTO THE BASE OF THE
TROUGH. HIGHS AROUND NORMAL SUNDAY WILL FALL IN TO THE 40S
MONDAY....AND THEN A MORE SIZABLE DROP TUESDAY AND THICKNESSES CRASH
TO NEAR OR BELOW 1260M TUESDAY MORNING. BASED ON THESE
THICKNESSES...LOWS COULD BE IN THE TEENS AND HIGHS IN THE LOW TO MID
30S. MODELS HAVE ONLY RECENTLY COME INTO BETTER AGREEMENT ON THESE
THICKNESSES...AND THE LACK OF SNOW COVER OVER THE MIDWEST LEADS TO
LOWER CONFIDENCE IN TEMPS BEING ON THE COLDER SIDE OF WHAT HAS
HISTORICALLY BEEN OBSERVED. DURING THIS PERIOD...ALL CYCLOGENESIS
ASSOCIATED WITH SHORTWAVES IN THE NORTHWEST FLOW ALOFT SHOULD STAY
WELL OFFSHORE...WITH THE ONLY SENSIBLE IMPACT WILL BE POSSIBLE
OROGRAPHIC CIRRUS MONDAY NIGHT OR TUESDAY NIGHT. BY THE END OF THE
PERIOD...MODELS INDICATE THE WEST COAST RIDGE MAY WEAKEN AND ALLOW
ENERGY TO CROSS INTO THE CENTRAL US AND BRING A BETTER CHANCE OF
PRECIP LATE NEXT WEEK INTO THE WEEKEND.
&&
.AVIATION /18Z THURSDAY THROUGH TUESDAY/...
AS OF 1250 PM THURSDAY...
24 HOUR TAF PERIOD:
LIGHT TO MODERATE RAIN WILL CONTINUE OVER THE WRN HALF OF THE AREA
AND SLOWLY MOVE EAST THIS EVENING AS THE SURFACE LOW TRACKS NE INTO
CENTRAL NC. HIGH CONFIDENCE THAT IFR AND LIFR AVIATION CONDITIONS
WILL CONTINUE THROUGH APPROX 12Z FRIDAY. RAIN WILL CHANGE TO SNOW
FROM WEST TO EAST...WITH SOME UNCERTAINTY ON THE EXACT TIMING OF THE
CHANGE OVER. FOR NOW HAVE SNOW STARTING AROUND 23Z AT KINT AND KGSO
TO 02-04Z AT KRDU AND KRWI...WITH THE CHANCE FOR A BRIEF PERIOD OF
SNOW AT KFAY AROUND 05Z FRIDAY. SNOW AND FOG WILL KEEP LIFR
CONDITIONS IN PLACE THROUGH 05Z-06Z. RESIDUAL LOW LEVEL MOISTURE MAY
KEEP VISBYS LOW EVEN AFTER THE SNOW ENDS. AVIATION CONDITIONS SHOULD
IMPROVE TO VFR AROUND SUNRISE. NNE WINDS AROUND 10-20 KTS THIS
EVENING WILL SHIFT TO THE NW AS THE FRONT MOVES THROUGH CENTRAL NC
OVERNIGHT.
LOOKING AHEAD:
VFR CONDITIONS EXPECTED FRIDAY NIGHT THROUGH TUESDAY.
&&
.RAH WATCHES/WARNINGS/ADVISORIES...
WINTER WEATHER ADVISORY FROM 6 PM THIS EVENING TO 4 AM EST FRIDAY
FOR NC028-042-043-077-078-083-084.
WINTER STORM WARNING FROM 6 PM THIS EVENING TO 4 AM EST FRIDAY FOR
NCZ007>011-021>027-038>041-073>076.
&&
$$
SYNOPSIS...HARTFIELD
NEAR TERM...HARTFIELD
SHORT TERM...SMITH
LONG TERM...SMITH
AVIATION...WSS
AREA FORECAST DISCUSSION
NWS RALEIGH NC
240 PM EST THU JAN 17 2013
.SYNOPSIS...
STRENGTHENING LOW PRESSURE OVER NORTHERN GEORGIA WILL TRACK TO THE
EAST NORTHEAST ACROSS SOUTHEAST NORTH CAROLINA THIS EVENING... THEN
OFF THE COAST LATE TONIGHT. COLD HIGH PRESSURE WILL BUILD IN FROM
THE WEST FRIDAY INTO THE WEEKEND.
&&
.NEAR TERM /THROUGH FRIDAY/...
AS OF 150 PM THURSDAY...
THROUGH TONIGHT: CONFIDENCE REMAINS HIGH IN THE OCCURRENCE OF
SIGNIFICANT BANDED SNOWFALL OVER NRN AND WRN PORTIONS OF NC EARLY
THIS EVENING THROUGH TONIGHT.
INTENSIFYING SURFACE LOW PRESSURE... LOCATED OVER NE GA EARLY THIS
AFTERNOON... WILL CONTINUE A STEADY ENE TRACK ALONG A FRONTAL ZONE
ACROSS SE NC. THE NAM/GFS/RAP/SREF MEAN HAVE EXHIBITED EXCELLENT
CONTINUITY THE LAST SEVERAL RUNS REGARDING TRACK AND TIMING... AND
HAVE SHOWN A VERY SMALL SOUTHWARD TREND IN THE EXTENT OF COLDER AIR.
DYNAMIC LIFT WITH THIS SYSTEM WILL BE EXTREMELY STRONG -- ESPECIALLY
ALOFT WITH HIGH OMEGA FOCUSED IN THE CRUCIAL -12C TO -20C LAYER
ALOFT -- BUT QUICK-HITTING. AN INTENSE UPPER DIVERGENCE MAX EXPECTED
TO BE ROUGHLY OVER THE SRN NC FOOTHILLS AT 00Z WILL MOVE NE THROUGH
CENTRAL NC BEFORE EXITING NE SECTIONS OF THE CWA BY AROUND 07Z. THIS
IS IN TANDEM WITH THE PASSAGE OF STRONG Q-VECTOR CONVERGENCE... MID
LEVEL DCVA AND A RISE/FALL COUPLET OF AROUND +/- 200 METERS...
STRONG LOW LEVEL THETA-E ADVECTION... AND DEEP MOIST ISENTROPIC
UPGLIDE. THE FACT THAT THIS SYSTEM IS STRENGTHENING QUICKLY UPON
ARRIVAL IS ESPECIALLY TROUBLING IN THAT THE RESULTANT RAPID MASS
FIELD ADJUSTMENTS ARE LIABLE TO SIGNIFICANT AND QUICKLY BOLSTER
ASCENT AND HEIGHTEN THE EXTENT AND INTENSITY OF THE SNOW BANDING.
MOISTURE AVAILABILITY WILL GENERALLY NOT BE A PROBLEM WITH VERY HIGH
PW (OVER 200 PERCENT OF NORMAL) AND A STRONG MOISTURE TRANSPORT FROM
THE GULF... ALTHOUGH THE INCOMING DRY SLOT ON THE SE SIDE OF THE LOW
WILL BE WORTH MONITORING AND MAY LIMIT WINTRY TOTALS IN THE
SOUTHEAST CWA (SEE BELOW). HOW FAST THE COLD AIR ARRIVES ESPECIALLY
ALOFT REMAINS A CONCERN... ALTHOUGH THE MODELS INITIALIZED WELL AND
ARE IN VERY GOOD AGREEMENT... BOOSTING CONFIDENCE IN THEIR TIMING OF
THE ANTICIPATED THERMAL CHANGES.
THE HEAVIEST SNOW BANDING IS LIKELY TO OCCUR OVER THE WRN AND NRN
PIEDMONT... FROM HIGH ROCK AND BADIN LAKES... ACROSS THE I-40 AND
HIGHWAY 64 CORRIDORS BETWEEN (AND INCLUDING) THE TRIAD AND THE
TRIANGLE... UP TO KERR LAKE AND LAKE GASTON... VERY ROUGHLY
FOLLOWING THE I-85 CORRIDOR TO THE NW... ALIGNED WITH THE AREA OF
STRONGEST DEFORMATION ALOFT. KEY TIMING STILL LOOKS TO BE FROM 23Z
UNTIL AROUND 07Z WITH A QUICK EXIT SOON THEREAFTER. SREF
PROBABILITIES HAVE BEEN VERY CONSISTENT IN SHOWING A 70+ PERCENT
CHANCE OF SNOWFALL RATES OVER ONE INCH PER HOUR ACROSS MUCH OF THE
PIEDMONT AND FAR NRN COASTAL PLAIN FROM MID EVENING UNTIL THE EARLY
OVERNIGHT HOURS. WITH THESE RATES AND THE TIMING OF A FEW HOURS OF
HEAVY BANDED SNOW (STARTING AS A RAIN/SNOW MIX)... STORM TOTAL
ACCUMULATIONS OF 2-4 INCHES IN THIS AREA WITH ISOLATED 5 INCH TOTALS
LOOK QUITE REASONABLE. BORDERING THE WARNING AREA... STILL EXPECT AN
INCH OR SO OF ACCUMULATION MAINLY ON GRASSY AREAS... WITH A LITTLE
SLUSH ON ROADS POSSIBLE.
SOUTH AND EAST OF HERE... INCLUDING FAYETTEVILLE AND CLINTON... A
QUICK BURST OF MAINLY SNOW IS POSSIBLE WITH STRONG DYNAMIC COOLING
THROUGH THE COLUMN AS THE LOW ALOFT PASSES BY... BUT THE WINDOW OF
OPPORTUNITY WILL BE VERY SHORT AS AMOUNTS/DURATION WILL BE GREATLY
LIMITED BY THE MID-UPPER LEVEL DRY SLOT ARRIVAL WITH NOTABLE DRYING
ABOVE THE -5C LEVEL... SUPPRESSING CRYSTAL GROWTH ALOFT... PLUS
BOUNDARY LAYER TEMPS SHOULD HOLD ABOVE FREEZING FOR MUCH OF THIS
EVENT... NOT DROPPING TO NEAR FREEZING UNTIL PRECIP IS NEARLY GONE.
EXPECT LIGHT ACCUMULATIONS OF A DUSTING CONFINED TO GRASSY AREAS.
A SIDE NOTE: MID LEVEL LAPSE RATE PROGS ARE QUITE INTERESTING...
INCLUDING THE 12 KM NAM WHICH INDICATES 850-500 MB VALUES OF 5.5-6.0
C/KM TRAVERSING THE CWA... JUST WNW OF THE 850 MB LOW TRACK...
PRIMARILY BETWEEN 03Z AND 06Z. AND RECENT RAP RUNS TAKE THE 700-400
MB LAPSE RATES (WHICH CAPTURES THE MIXED PHASE REGION ALOFT) UP TO
7.0 C/KM OVER THE NW PIEDMONT TOWARD MIDNIGHT. CONSIDERING THIS
POSSIBILITY FOR UPRIGHT INSTABILITY COMBINED WITH VIGOROUS DYNAMIC
LIFT... A FEW LIGHTNING STRIKES WITHIN SNOW BANDS ARE CERTAINLY
POSSIBLE... ALTHOUGH LIKELY TOO ISOLATED TO INCLUDE IN THE FORECAST
AT THIS TIME.
STRENGTHENING WINDS WILL BE AN ISSUE AS WELL WITH THE TIGHTENING
MSLP GRADIENT AS THE LOW APPROACHES. WE ARE ALREADY SEEING FREQUENT
GUSTS TO 25-40 KTS (ALTHOUGH SOME OF THIS MAY BE AUGMENTED BY A
POSSIBLE GRAVITY WAVE). EXPECT A PERIOD OF SUSTAINED WINDS OF 15-25
MPH WITH SPORADIC GUSTS TO AROUND 30 MPH FROM LATE AFTERNOON UNTIL
AROUND 1-2 AM.
TEMPS SHOULD STEADILY DROP THROUGH THE REST OF THE AFTERNOON AND
NIGHT. -GIH
&&
.SHORT TERM /FRIDAY NIGHT THROUGH SATURDAY NIGHT/...
AS OF 240 PM THURSDAY...
A 1032MB HIGH PRESSURE WILL SETTLE OVERHEAD FRIDAY NIGHT...ALLOWING
FOR GOOD RADIATIONAL COOLING UNDER CLEAR SKIES. THERE MAY BE SOME
SHADED AREAS WHERE SNOW COVER IS ABLE TO LINGER THROUGH THE DAY
FRIDAY...WHICH MAY HELP RADIATIONAL COOLING IN A FEW SPOTS...BUT
OVERALL GUIDANCE SUPPORTS LOWS IN THE MID 20S. THE UPPER LEVEL FLOW
WILL REMAIN RELATIVELY FLAT SATURDAY WHILE THE SURFACE HIGH SHIFTS
SLIGHTLY SOUTHWARD. THE SHALLOW COOLER AIRMASS WILL ONLY SLIGHTLY
MODIFY WITH WEAK VERTICAL MIXING...LEADING TO HIGHS IN THE MID 40S
TO LOWER 50S. LOWS SATURDAY NIGHT IN THE UPPER 20S TO LOWER 30S
&&
.LONG TERM /SUNDAY THROUGH THURSDAY/...
AS OF 240 PM THURSDAY...
THE UPPER LEVEL PATTERN WILL BEGIN A SLOW AMPLIFICATION SUNDAY AS
RIDGING BUILDS OUT WEST AND A DEEP TROUGH DEVELOPS OVER THE EASTERN
US. A COLD NORTHWESTERLY FLOW WILL PERSIST THROUGH MIDWEEK... A
COUPLE REINFORCING SHOTS OF ARCTIC AIR VIA DRY COLD FRONTS AS
SHORTWAVES ROTATE SOUTHEAST OUT OF CANADA AND INTO THE BASE OF THE
TROUGH. HIGHS AROUND NORMAL SUNDAY WILL FALL IN TO THE 40S
MONDAY....AND THEN A MORE SIZABLE DROP TUESDAY AND THICKNESSES CRASH
TO NEAR OR BELOW 1260M TUESDAY MORNING. BASED ON THESE
THICKNESSES...LOWS COULD BE IN THE TEENS AND HIGHS IN THE LOW TO MID
30S. MODELS HAVE ONLY RECENTLY COME INTO BETTER AGREEMENT ON THESE
THICKNESSES...AND THE LACK OF SNOW COVER OVER THE MIDWEST LEADS TO
LOWER CONFIDENCE IN TEMPS BEING ON THE COLDER SIDE OF WHAT HAS
HISTORICALLY BEEN OBSERVED. DURING THIS PERIOD...ALL CYCLOGENESIS
ASSOCIATED WITH SHORTWAVES IN THE NORTHWEST FLOW ALOFT SHOULD STAY
WELL OFFSHORE...WITH THE ONLY SENSIBLE IMPACT WILL BE POSSIBLE
OROGRAPHIC CIRRUS MONDAY NIGHT OR TUESDAY NIGHT. BY THE END OF THE
PERIOD...MODELS INDICATE THE WEST COAST RIDGE MAY WEAKEN AND ALLOW
ENERGY TO CROSS INTO THE CENTRAL US AND BRING A BETTER CHANCE OF
PRECIP LATE NEXT WEEK INTO THE WEEKEND.
&&
.AVIATION /18Z THURSDAY THROUGH TUESDAY/...
AS OF 1250 PM THURSDAY...
24 HOUR TAF PERIOD:
LIGHT TO MODERATE RAIN WILL CONTINUE OVER THE WRN HALF OF THE AREA
AND SLOWLY MOVE EAST THIS EVENING AS THE SURFACE LOW TRACKS NE INTO
CENTRAL NC. HIGH CONFIDENCE THAT IFR AND LIFR AVIATION CONDITIONS
WILL CONTINUE THROUGH APPROX 12Z FRIDAY. RAIN WILL CHANGE TO SNOW
FROM WEST TO EAST...WITH SOME UNCERTAINTY ON THE EXACT TIMING OF THE
CHANGE OVER. FOR NOW HAVE SNOW STARTING AROUND 23Z AT KINT AND KGSO
TO 02-04Z AT KRDU AND KRWI...WITH THE CHANCE FOR A BRIEF PERIOD OF
SNOW AT KFAY AROUND 05Z FRIDAY. SNOW AND FOG WILL KEEP LIFR
CONDITIONS IN PLACE THROUGH 05Z-06Z. RESIDUAL LOW LEVEL MOISTURE MAY
KEEP VISBYS LOW EVEN AFTER THE SNOW ENDS. AVIATION CONDITIONS SHOULD
IMPROVE TO VFR AROUND SUNRISE. NNE WINDS AROUND 10-20 KTS THIS
EVENING WILL SHIFT TO THE NW AS THE FRONT MOVES THROUGH CENTRAL NC
OVERNIGHT.
LOOKING AHEAD:
VFR CONDITIONS EXPECTED FRIDAY NIGHT THROUGH TUESDAY.
&&
.RAH WATCHES/WARNINGS/ADVISORIES...
WINTER WEATHER ADVISORY FROM 6 PM THIS EVENING TO 4 AM EST FRIDAY
FOR NC028-042-043-077-078-083-084.
WINTER STORM WARNING FROM 6 PM THIS EVENING TO 4 AM EST FRIDAY FOR
NCZ007>011-021>027-038>041-073>076.
&&
$$
SYNOPSIS...HARTFIELD/KC
NEAR TERM...HARTFIELD
SHORT TERM...SMITH
LONG TERM...SMITH
AVIATION...WSS
AREA FORECAST DISCUSSION
NWS RALEIGH NC
152 PM EST THU JAN 17 2013
.SYNOPSIS...
STRENGTHENING LOW PRESSURE OVER NORTHEEAST GEORGIA THIS AFTERNOON
WILL TRACK TO THE EAST NORTHEAST ACROSS SOUTHEAST NORTH CAROLINA
THIS EVENING THROUGH MIDNIGHT... THEN OFF THE COAST LATE TONIGHT.
COLD HIGH PRESSURE WILL BUILD IN FROM THE WEST FRIDAY INTO THE
WEEKEND.
&&
.NEAR TERM /THROUGH FRIDAY/...
AS OF 150 PM THURSDAY...
THROUGH TONIGHT: CONFIDENCE REMAINS HIGH IN THE OCCURRENCE OF
SIGNIFICANT BANDED SNOWFALL OVER NRN AND WRN PORTIONS OF NC EARLY
THIS EVENING THROUGH TONIGHT.
INTENSIFYING SURFACE LOW PRESSURE... LOCATED OVER NE GA EARLY THIS
AFTERNOON... WILL CONTINUE A STEADY ENE TRACK ALONG A FRONTAL ZONE
ACROSS SE NC. THE NAM/GFS/RAP/SREF MEAN HAVE EXHIBITED EXCELLENT
CONTINUITY THE LAST SEVERAL RUNS REGARDING TRACK AND TIMING... AND
HAVE SHOWN A VERY SMALL SOUTHWARD TREND IN THE EXTENT OF COLDER AIR.
DYNAMIC LIFT WITH THIS SYSTEM WILL BE EXTREMELY STRONG -- ESPECIALLY
ALOFT WITH HIGH OMEGA FOCUSED IN THE CRUCIAL -12C TO -20C LAYER
ALOFT -- BUT QUICK-HITTING. AN INTENSE UPPER DIVERGENCE MAX EXPECTED
TO BE ROUGHLY OVER THE SRN NC FOOTHILLS AT 00Z WILL MOVE NE THROUGH
CENTRAL NC BEFORE EXITING NE SECTIONS OF THE CWA BY AROUND 07Z. THIS
IS IN TANDEM WITH THE PASSAGE OF STRONG Q-VECTOR CONVERGENCE... MID
LEVEL DCVA AND A RISE/FALL COUPLET OF AROUND +/- 200 METERS...
STRONG LOW LEVEL THETA-E ADVECTION... AND DEEP MOIST ISENTROPIC
UPGLIDE. THE FACT THAT THIS SYSTEM IS STRENGTHENING QUICKLY UPON
ARRIVAL IS ESPECIALLY TROUBLING IN THAT THE RESULTANT RAPID MASS
FIELD ADJUSTMENTS ARE LIABLE TO SIGNIFICANT AND QUICKLY BOLSTER
ASCENT AND HEIGHTEN THE EXTENT AND INTENSITY OF THE SNOW BANDING.
MOISTURE AVAILABILITY WILL GENERALLY NOT BE A PROBLEM WITH VERY HIGH
PW (OVER 200 PERCENT OF NORMAL) AND A STRONG MOISTURE TRANSPORT FROM
THE GULF... ALTHOUGH THE INCOMING DRY SLOT ON THE SE SIDE OF THE LOW
WILL BE WORTH MONITORING AND MAY LIMIT WINTRY TOTALS IN THE
SOUTHEAST CWA (SEE BELOW). HOW FAST THE COLD AIR ARRIVES ESPECIALLY
ALOFT REMAINS A CONCERN... ALTHOUGH THE MODELS INITIALIZED WELL AND
ARE IN VERY GOOD AGREEMENT... BOOSTING CONFIDENCE IN THEIR TIMING OF
THE ANTICIPATED THERMAL CHANGES.
THE HEAVIEST SNOW BANDING IS LIKELY TO OCCUR OVER THE WRN AND NRN
PIEDMONT... FROM HIGH ROCK AND BADIN LAKES... ACROSS THE I-40 AND
HIGHWAY 64 CORRIDORS BETWEEN (AND INCLUDING) THE TRIAD AND THE
TRIANGLE... UP TO KERR LAKE AND LAKE GASTON... VERY ROUGHLY
FOLLOWING THE I-85 CORRIDOR TO THE NW... ALIGNED WITH THE AREA OF
STRONGEST DEFORMATION ALOFT. KEY TIMING STILL LOOKS TO BE FROM 23Z
UNTIL AROUND 07Z WITH A QUICK EXIT SOON THEREAFTER. SREF
PROBABILITIES HAVE BEEN VERY CONSISTENT IN SHOWING A 70+ PERCENT
CHANCE OF SNOWFALL RATES OVER ONE INCH PER HOUR ACROSS MUCH OF THE
PIEDMONT AND FAR NRN COASTAL PLAIN FROM MID EVENING UNTIL THE EARLY
OVERNIGHT HOURS. WITH THESE RATES AND THE TIMING OF A FEW HOURS OF
HEAVY BANDED SNOW (STARTING AS A RAIN/SNOW MIX)... STORM TOTAL
ACCUMULATIONS OF 2-4 INCHES IN THIS AREA WITH ISOLATED 5 INCH TOTALS
LOOK QUITE REASONABLE. BORDERING THE WARNING AREA... STILL EXPECT AN
INCH OR SO OF ACCUMULATION MAINLY ON GRASSY AREAS... WITH A LITTLE
SLUSH ON ROADS POSSIBLE.
SOUTH AND EAST OF HERE... INCLUDING FAYETTEVILLE AND CLINTON... A
QUICK BURST OF MAINLY SNOW IS POSSIBLE WITH STRONG DYNAMIC COOLING
THROUGH THE COLUMN AS THE LOW ALOFT PASSES BY... BUT THE WINDOW OF
OPPORTUNITY WILL BE VERY SHORT AS AMOUNTS/DURATION WILL BE GREATLY
LIMITED BY THE MID-UPPER LEVEL DRY SLOT ARRIVAL WITH NOTABLE DRYING
ABOVE THE -5C LEVEL... SUPPRESSING CRYSTAL GROWTH ALOFT... PLUS
BOUNDARY LAYER TEMPS SHOULD HOLD ABOVE FREEZING FOR MUCH OF THIS
EVENT... NOT DROPPING TO NEAR FREEZING UNTIL PRECIP IS NEARLY GONE.
EXPECT LIGHT ACCUMULATIONS OF A DUSTING CONFINED TO GRASSY AREAS.
A SIDE NOTE: MID LEVEL LAPSE RATE PROGS ARE QUITE INTERESTING...
INCLUDING THE 12 KM NAM WHICH INDICATES 850-500 MB VALUES OF 5.5-6.0
C/KM TRAVERSING THE CWA... JUST WNW OF THE 850 MB LOW TRACK...
PRIMARILY BETWEEN 03Z AND 06Z. AND RECENT RAP RUNS TAKE THE 700-400
MB LAPSE RATES (WHICH CAPTURES THE MIXED PHASE REGION ALOFT) UP TO
7.0 C/KM OVER THE NW PIEDMONT TOWARD MIDNIGHT. CONSIDERING THIS
POSSIBILITY FOR UPRIGHT INSTABILITY COMBINED WITH VIGOROUS DYNAMIC
LIFT... A FEW LIGHTNING STRIKES WITHIN SNOW BANDS ARE CERTAINLY
POSSIBLE... ALTHOUGH LIKELY TOO ISOLATED TO INCLUDE IN THE FORECAST
AT THIS TIME.
STRENGTHENING WINDS WILL BE AN ISSUE AS WELL WITH THE TIGHTENING
MSLP GRADIENT AS THE LOW APPROACHES. WE ARE ALREADY SEEING FREQUENT
GUSTS TO 25-40 KTS (ALTHOUGH SOME OF THIS MAY BE AUGMENTED BY A
POSSIBLE GRAVITY WAVE). EXPECT A PERIOD OF SUSTAINED WINDS OF 15-25
MPH WITH SPORADIC GUSTS TO AROUND 30 MPH FROM LATE AFTERNOON UNTIL
AROUND 1-2 AM.
TEMPS SHOULD STEADILY DROP THROUGH THE REST OF THE AFTERNOON AND
NIGHT. -GIH
&&
.SHORT TERM /FRIDAY THROUGH SATURDAY NIGHT/...
AS OF 245 AM THURSDAY...
QUITE WEATHER IS EXPECTED TO FINALLY RETURN BY FRIDAY... WITH
SUBSIDENCE AND DRYING IN THE WAKE OF THE THE QUICK MOVING STRONG
S/W... WHICH WILL LIFT OFF TO THE NORTHEAST OF THE AREA ON FRIDAY.
THIS WILL YIELD SUNNY SKIES FOR CENTRAL NC. HOWEVER... AFTERNOON LOW
LEVEL THICKNESS VALUES ARE EXPECTED TO STRUGGLE TO REACH 1300
METERS. THIS COUPLED WITH POSSIBLY SOME SNOW ON THE GROUND ACROSS
PORTIONS OF THE AREA WILL KEEP HIGH TEMPERATURES CHILLY. WILL GO
HIGH TEMPS RANGING FROM THE LOW 40S ACROSS THE NORTH TO UPPER 40S
ACROSS THE SOUTH.
SURFACE HIGH PRESSURE WILL SETTLE OVER THE AREA FOR FRIDAY NIGHT...
BEFORE SHIFTING OFFSHORE ON SATURDAY... WHILE MID/UPPER LEVEL FLOW
GENERALLY REMAINS WESTERLY. THIS WILL CONTINUE TO YIELD SUNNY/CLEAR
SKIES ACROSS THE AREA... WITH A COLD SATURDAY MORNING GIVEN THE
CLEAR SKIES AND CALM TO LIGHT AND VARIABLE WINDS. THUS... WILL GO
WITH LOWS IN THE LOW TO MID 20S FOR SATURDAY MORNING. HIGHS SATURDAY
SHOULD BE WARMER THAN FRIDAY... AS A SOUTHERLY RETURN FLOW DEVELOPS
AND AFTERNOON LOW LEVEL THICKNESS VALUES REBOUND INTO THE 1320S.
HOWEVER... STILL THINK WE WILL SEE HIGH TEMPS ONLY REBOUND TO NEAR
NORMAL OR SLIGHTLY BELOW NORMAL... GENERALLY IN THE UPPER 40S TO
LOWER 50S... AS THE MIXED LAYER WILL BE QUITE SHALLOW. TEMPS SUNDAY
MORNING WILL FOLLOW THE SAME TREND (WARMER THAN THE PREVIOUS
MORNING)... WITH LOWS EXPECTED TO GENERALLY RANGE FROM 30-35 DEGREES.
&&
.LONG TERM /SUNDAY THROUGH WEDNESDAY/...
AS OF 3 AM THURSDAY...
MID/UPPER FLOW IS EXPECTED TO BECOME MORE AMPLIFIED WITH A DEEP
TROUGH DEVELOPING ACROSS THE EASTERN U.S.... ALLOWING MUCH COLDER
AIR TO SURGE INTO THE AREA EARLY NEXT WEEK. A COUPLE OF DRY COLD
FRONT ARE EXPECTED TO MOVE THROUGH THE AREA DURING THIS TIMEFRAME...
ONE LATE SUNDAY INTO SUNDAY AND ANOTHER POSSIBLE DRY COLD FRONT ON
WEDNESDAY. SUNDAY LOOKS TO BE THE WARMEST DAY OF THE MEDIUM RANGE
RANGE... AHEAD OF A STRONG COLD FRONT WHICH SHOULD BRING SOME OF THE
COLD AIR YET OF THE WINTER SEASON. THUS... EXPECT HIGHS SUNDAY WILL
RANGE FROM AROUND 50 NW TO NEAR 60 SOUTH/SOUTHEAST (A BIT OF TRICKY
TEMP FORECAST THOUGH GIVEN ABOUT 6 TO 9 HOURS DIFFERENCE BETWEEN THE
GFS AND ECWMF). HIGHS AND LOW TEMPS FOR THE REMAINDER OF THE PERIOD
ARE EXPECTED TO BE BELOW NORMAL... WITH LOW TEMPS GENERALLY IN THE
20S... WITH POSSIBLY EVEN SOME TEENS BY TUESDAY MORNING IN THE COLD
OUTLYING AREAS. HIGH TEMPS ARE GENERALLY EXPECTED TO BE IN THE
40S... WITH MAYBE A FEW LOCATIONS ACROSS THE NORTH ON TUESDAY
STRUGGLING TO REACH 40 DEGREES.
&&
.AVIATION /18Z THURSDAY THROUGH TUESDAY/...
AS OF 1250 PM THURSDAY...
24 HOUR TAF PERIOD:
LIGHT TO MODERATE RAIN WILL CONTINUE OVER THE WRN HALF OF THE AREA
AND SLOWLY MOVE EAST THIS EVENING AS THE SURFACE LOW TRACKS NE INTO
CENTRAL NC. HIGH CONFIDENCE THAT IFR AND LIFR AVIATION CONDITIONS
WILL CONTINUE THROUGH APPROX 12Z FRIDAY. RAIN WILL CHANGE TO SNOW
FROM WEST TO EAST...WITH SOME UNCERTAINTY ON THE EXACT TIMING OF THE
CHANGE OVER. FOR NOW HAVE SNOW STARTING AROUND 23Z AT KINT AND KGSO
TO 02-04Z AT KRDU AND KRWI...WITH THE CHANCE FOR A BRIEF PERIOD OF
SNOW AT KFAY AROUND 05Z FRIDAY. SNOW AND FOG WILL KEEP LIFR
CONDITIONS IN PLACE THROUGH 05Z-06Z. RESIDUAL LOW LEVEL MOISTURE MAY
KEEP VISBYS LOW EVEN AFTER THE SNOW ENDS. AVIATION CONDITIONS SHOULD
IMPROVE TO VFR AROUND SUNRISE. NNE WINDS AROUND 10-20 KTS THIS
EVENING WILL SHIFT TO THE NW AS THE FRONT MOVES THROUGH CENTRAL NC
OVERNIGHT.
LOOKING AHEAD:
VFR CONDITIONS EXPECTED FRIDAY NIGHT THROUGH TUESDAY.
&&
.RAH WATCHES/WARNINGS/ADVISORIES...
WINTER WEATHER ADVISORY FROM 6 PM THIS EVENING TO 4 AM EST FRIDAY
FOR NC028-042-043-077-078-083-084.
WINTER STORM WARNING FROM 6 PM THIS EVENING TO 4 AM EST FRIDAY FOR
NCZ007>011-021>027-038>041-073>076.
&&
$$
SYNOPSIS...HARTFIELD/KC
NEAR TERM...HARTFIELD
SHORT TERM...BSD
LONG TERM...BSD
AVIATION...WSS
AREA FORECAST DISCUSSION
NWS WILMINGTON OH
1250 PM EST THU JAN 17 2013
.SYNOPSIS...
CLOUD COVER WILL CONTINUE FOR MUCH OF TODAY AS THE OHIO VALLEY
RESIDES BETWEEN LOW PRESSURE TO THE SOUTH...AND HIGH PRESSURE TO
THE WEST. THE HIGH WILL BUILD EASTWARD TONIGHT...BRINGING THE AREA
A PERIOD OF SEASONABLE TEMPERATURES AND FAIR WEATHER THROUGH
SATURDAY. SOME SNOW SHOWERS WILL BECOME POSSIBLE SATURDAY NIGHT AS
AN ARCTIC AIRMASS BEGINS TO MOVE INTO OUR REGION.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
AMPLE CLOUD COVER EXTENDS ACROSS THE AREA UNDER A DENSE HIGH
CLOUD CANOPY ASSOCIATED WITH A STRONG UPPER LEVEL JET. PATCHES OF
LOW CLOUDS ARE ALSO OCCURRING UNDER THIS DECK PRIMARILY ASSOCIATED
WITH MOIST LOW LEVEL NORTHERLY FLOW. MODELS ARE IN DISAGREEMENT ON
HOW TO HANDLE THIS LOW LEVEL MOISTURE AS WE GO THROUGH THE DAY.
THE HIGH CLOUDS WILL GRADUALLY SHIFT EAST AS THE JET MAX EXITS OUR
REGION TODAY. THE RAP INDICATES THAT MUCH OF THE LOW CLOUD COVER
WILL CONTINUE THROUGHOUT THE DAY. THE NAM SUGGESTS CLEARING THIS
AFTERNOON. FOLLOWING THE PERSISTENT TREND FOR THE PAST SEVERAL
DAYS...WILL BE PESSIMISTIC ABOUT CLEARING TODAY. THIS WILL RESULT
IN HIGH TEMPERATURES IN THE 30S.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH SUNDAY/...
A WEAK COLD FRONT WILL PASS ACROSS THE AREA TONIGHT. THIS FRONT
WILL BE MOISTURE STARVED SO KEPT ANY MENTION OF FLURRIES...THAT
HI RES MODELS ARE SUGGESTING...OUT OF THE FORECAST. HIGH PRESSURE
WILL BEGIN TO BUILD BEHIND THIS WEAK FRONT LATE TONIGHT AND INTO
THE DAY FRIDAY. THIS SHOULD FINALLY PROVIDE FOR SOME CLEARING
SKIES...ESPECIALLY ACROSS THE SOUTH AND CLOSER TO THE RIDGE
CENTER. TEMPERATURES WILL REMAIN GENERALLY SEASONABLE THURSDAY
NIGHT AND FRIDAY.
BY FRIDAY NIGHT SOME RETURN FLOW WILL DEVELOP WITH THE LOW LEVEL
PRESSURE GRADIENT INCREASING AS THE RIDGE SHIFTS ACROSS THE
SOUTHEASTERN CONUS AND LOW PRESSURE BEGINS TO PUSH EASTWARD
ACROSS THE GREAT LAKES. WARMER TEMPERATURES MOVING IN AS WELL AS
WINDS KEEPING UP OVERNIGHT WILL LIKELY KEEP TEMPERATURES IN THE
UPPER 20S FOR THE MOST PART.
SURFACE GRADIENT WILL TIGHTEN FURTHER ON SATURDAY AS THE LOW
PASSES TO OUR NORTH WHICH WILL PROVIDE BREEZY SOUTHWEST WINDS AND
A RATHER MILD DAY. TEMPERATURES WILL LIKELY TOP OUT IN THE MIDDLE
40S ACROSS THE NORTH TO THE LOWER 50S ACROSS THE SOUTH.
A DEEP UPPER TROUGH BEGINS TO DIG SOUTH INTO OUR REGION SATURDAY
NIGHT AS THE SURFACE LOW REACHES THE EASTERN GREAT LAKES. AS THIS
OCCURS...AN ARCTIC COLD FRONT WILL ARRIVE AT OUR DOORSTEP. SOME
LIGHT PRECIPITATION IN THE FORM OF SNOW SHOWERS LOOKS
POSSIBLE BEHIND THIS FRONT...ESPECIALLY ACROSS THE NORTHERN
PORTIONS OF THE FORECAST AREA. BEHIND THIS STRONG COLD
FRONT...BREEZY NORTHWEST WINDS WILL BRING MUCH COLDER AND DRIER
AIR ACROSS THE REGION SUNDAY.
&&
.LONG TERM /SUNDAY NIGHT THROUGH THURSDAY/...
WEAK SHORT WAVES WILL BRING A SLIGHT CHANCE FOR SNOW SHOWERS ON
MONDAY AND AGAIN ON TUESDAY NIGHT. OTHERWISE...PRECIPITATION IS
NOT EXPECTED IN THE MODIFIED ARCTIC AIRMASS.
ABOVE NORMAL HIGHS ARE EXPECTED FOR SATURDAY IN A BRIEF ROUND OF
WARM ADVECTION AND SOLAR HEATING. IN THE COLDER AIRMASS THAT WILL BE
AROUND FOR THE REST OF THE PERIOD...TEMPERATURES WILL BE WELL BELOW
NORMAL. TUESDAY MAY BE THE COLDEST DAY...WITH HIGHS NOT FORECAST TO
REACH 20 IN MOST LOCATIONS.
&&
.AVIATION /18Z THURSDAY THROUGH TUESDAY/...
HIGH PRESSURE WILL BUILD INTO THE REGION TONIGHT AND WILL MOVE OFF
TO THE SOUTHEAST ON FRIDAY. A WARM FRONT IS FORECAST TO PIVOT
NORTHEAST ACROSS THE GREAT LAKES ON FRIDAY.
MODELS CONTINUE TO OFFER VARYING SOLUTIONS ON THE AMOUNT OF LOW
LEVEL MOISTURE PRESENT ACROSS THE REGION AHEAD OF A WEAKENING COLD
FRONT. VISIBLE SATELLITE IMAGERY HAS BEEN SHOWING LOW LEVEL
CUMULUS DEVELOPING ACROSS NW OHIO INTO CENTRAL INDIANA.
ATTM...EXPECT A PERIOD OF MVFR CIGS AT KDAY AND HAVE ONLY PLACED
SCATTERED CUMULUS ELSEWHERE. WILL CONTINUE TO MONITOR.
OTHERWISE...AM EXPECTING DIURNAL CUMULUS CLOUDS TO DISSIPATE AFTER
SUNSET.
FOR THE OVERNIGHT PERIOD...MODELS AGAIN KEEP HINTING AT SOME LOW
LEVEL MOISTURE ADVECTING CLOSE TO THE NORTHERN TAF SITES OF KDAY
AND KCMH. I DO NOT HAVE CONFIDENCE ATTM TO PLACE IN THE TAF SO
HAVE LEFT MAINLY CLEAR SKIES FOR NOW.
ON FRIDAY...AVIATORS CAN EXPECTED MID AND HIGH LEVEL CLOUDS TO
ADVECT ACROSS THE REGION AS THEY SPILL INTO THE REGION IN ADVANCE
OF AFOREMENTIONED WARM FRONT. VFR CONDITIONS SHOULD PREVAIL.
OUTLOOK...NO SIGNIFICANT WEATHER IS EXPECTED.
&&
.ILN WATCHES/WARNINGS/ADVISORIES...
OH...NONE.
KY...NONE.
IN...NONE.
&&
$$
SYNOPSIS...LATTO
NEAR TERM...HICKMAN/LATTO
SHORT TERM...LATTO
LONG TERM...CONIGLIO
AVIATION...HICKMAN/JGL
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
528 PM EST THU JAN 17 2013
.SYNOPSIS...
AN ARCTIC FRONTAL BOUNDARY WILL SAG INTO NORTHERN PENNSYLVANIA
THIS EVENING. AT THE SAME TIME...A DEVELOPING STORM WILL PASS
JUST TO THE SOUTH OF THE STATE. AFTER A COLD DAY ON FRIDAY...
TEMPERATURES WILL MODERATE A BIT ON SATURDAY BEFORE A SHOT OF MUCH
COLDER AIR ARRIVES SUNDAY. TEMPERATURES WILL DIP TO NEAR OR BELOW
ZERO IN PARTS OF THE AREA NEXT WEEK AS THE COLDEST AIR OF THE
SEASON MOVES IN.
&&
.NEAR TERM /UNTIL 6 AM FRIDAY MORNING/...
5 PM UPDATE...
THICK...MULTI-LAYERED CLOUD SHIELD CONTINUES TO STREAM NE OVER
THE AREA FROM THE DEVELOPING WAVE OVER THE SERN US. NRN EDGE OF
THE PRECIP IS ACROSS SRN WVA AND NRN VA /JUST SOUTH OF THE D.C.
AREA/. HRRR AND 4KM NAM SHOWS THE NRN EDGE OF THE PRECIP REMAINING
STATIONARY THEN SAGGING SLOWLY SOUTH AND EAST THROUGH THIS
EVENING. THIS AGREES WITH THE LATEST TRENDS ON THE KLWX 88D.
MAIN CONCERN FOR THIS EVENING FOR ANY MEASURABLE PRECIP WILL BE
INVOF A SLOW MOVING EAST/WEST ARCTIC BOUNDARY DRAPED ACROSS
SOUTHERN NEW YORK. SOME VERY WEAK...AND FLEETING ISENTROPIC LIFT
NEAR THE 275K THETA SFC /AHEAD OF A WEAK WAVE OF LOW PRESSURE
ALONG THE BOUNDARY/ WILL SUPPORT AN AREA OF LIGHT SNOW POSSIBLY
DRIFTING SOUTH OF THE PENN/NY BORDER. A LIGHT COATING OF SNOW IS
POSSIBLE NEAR AND TO THE NORTH OF ROUTE 6. THIS FRONT WILL
FOLLOWED BY SOME LAKE EFFECT SNOW SHOWERS ACRS NWRN PENN BY
MIDNIGHT. THE SNOW SHOWERS SHOULD CONTINUE INTO FRIDAY MORNING.
STRATO CU CLOUD TEMPS BENEATH THE SUBSIDENCE INVERSION /THAT WILL
BRIEFLY POKE UP TO AROUND 7-8 KFT AGL THIS EVENING/ WILL BE
IN THE FAVORABLE DENDRITIC GROWTH ZONE...SO SOME NARROW SNOW BANDS
COULD DROP A QUICK INCH OR TWO NEAR AND TO THE WEST OF KBFD.
ELSEWHERE ACROSS THE CENTRAL MTNS AND SUSQ VALLEY REGION...NOTHING
MORE THAN SOME FLURRIES ARE POSSIBLE.
TEMPS THIS EVENING WILL VARY FROM THE MID AND UPPER 20S ALONG THE
PA/NY BORDER...TO THE LOWER AND MID 30S THROUGHOUT THE CENTRAL AND
SOUTHERN VALLEYS.
LOWS TONIGHT WILL BE VERY NEAR TO SLIGHTLY BELOW NORMAL.
&&
.SHORT TERM /6 AM FRIDAY MORNING THROUGH 6 PM FRIDAY/...
LATEST GUIDANCE STILL KEEPS THE SRN STREAM SYSTEM ROLLING TO THE
EAST-NORTHEAST...KEEPING THE THREAT OF PRECIP SOUTH OF THE MASON-
DIXON LINE. THE WAVE IS MADE TO DEEPEN OFF SHORE FRIDAY AS IT
SPEEDS AWAY...BEING REPLACED BY A STRONG HIGH FROM THE TN VALLEY.
CLEARING IS POSSIBLE ON FRIDAY AS THE ADVECTION CHANGES SIGN IN
THE AFTN...AND WE SEE THE ARCTIC AIR BEAT A QUICK RETREAT OFF TO
THE NORTHEAST AS THE FLOW GOES SW ON THE BACK SIDE OF THE HIGH.
DESPITE THE WARM ADVECTION THAT IS EXPECTED TO DEVELOP DURING THE
DAY...HIGHS IN THE 20S AND 30S WILL STILL AVERAGE WELL BELOW
NORMAL.
&&
.LONG TERM /FRIDAY NIGHT THROUGH THURSDAY/...
SFC HIGH PRES WILL SLIDE ENEWD FROM THE TN VLY INTO THE SRN MID ATLC
FRIDAY EVENING BEFORE EXPANDING ACRS THE SE STATES INTO SATURDAY.
A STRONG AND RELATIVELY MILD SWLY LLVL FLOW /40-50KT LLJ/ IN-BTWN
THE AFOREMENTIONED SFC HIGH AND CLIPPER LOW CROSSING THE UPPER GRT
LKS WILL PRODUCE STG LOW-MID LVL WAA...PUSHING 850MB TEMPS ABV 0C
IN MOST AREAS ON SAT. THIS SHOULD RESULT IN A BRIEF WARM-UP ON
SATURDAY WITH HIGHS PROJECTED TO CLIMB SEVERAL DEGREES ABV NORMAL.
H5 SHORTWAVE TROUGH AND ASSOCD CLIPPER SFC LOW WILL TRACK EWD ACRS
SRN ONTARIO INTO THE ST. LAWRENCE RIVER VALLEY SAT NGT INTO EARLY
SUNDAY. MODELS REMAIN IN GOOD AGREEMENT IN PLOWING AN ARCTIC FRONT
SEWD ACRS THE CWA EARLY SUNDAY WITH TEMPS ALOFT PLUMMETING TO -10
TO -15C AT 850MB BY 00Z MONDAY. THE POTNL MAY EXIST FOR HIGH
IMPACT SUB-ADVY /HISA/ SNOW SQUALLS WITH THE ARCTIC FROPA...WHICH
COULD CAUSE RAPID WHITE-OUT CONDS. SOME LAKE EFFECT SNOW SHOWERS
ARE ALSO POSSIBLE OVER THE NW MTNS.
*THE NDFD WEB GRAPHICS SHOW "HEAVY SNOW" FOR SAT NGT/EARLY SUNDAY.
WE ARE NOT EXPECTING HEAVY SNOW IN A LITERAL SENSE...BUT HAVE
INSERTED +SW /HEAVY SQUALLS/ INTO THE GRIDS WHICH GETS TRANSLATED
INTO HEAVY SNOW ON THE NDFD WEB GRAPHICS.* HEAVY SNOW SQUALLS
PRODUCE INTENSE BURSTS OF SNOW WITH ACCUMS GENERALLY LESS THAN 1"
OVER A SHORT DURATION.
MEDIUM RANGE MODEL AND ENSEMBLE GUIDANCE REMAINS IN VERY GOOD
AGREEMENT IN DEPICTING A DEEP TROUGH OVER THE ERN U.S....WITH A
VERY COLD POLAR VORTEX /-40C AT 500MB/ SITUATED OVER HUDSON BAY.
THE STRONG COLD SIGNAL IN THE LARGE SCALE PATTERN WILL SUPPORT
HIGH CONFIDENCE IN BELOW NORMAL TEMPERATURES THROUGH THE PERIOD.
PRELIM DAY 4-7 MAX/MIN TEMPS WERE DERIVED USING AN EVEN BLEND OF
17/00Z HPC/NAEFS/GFS/ECMWF MOS DATA. INITIAL VERIFICATION OF THE
EXPERIMENTAL 00Z ECMWF MOS DATA HAS SHOWN INCREASED SKILL OVER THE
GFS-BASED GUIDANCE AT THIS RANGE...AND IS NOTABLY COLDER EARLY NEXT
WEEK WHEN TEMPS SHOULD REACH THEIR BOTTOM...WITH -20C AIR AT H85.
FINAL AFTN TEMPS WERE NUDGED TOWARD THE 12Z GMOS WHICH RESULTED
IN ONLY MINOR CHANGES TO PRELIM FCST.
THE WELL-ADVERTISED MODIFIED ARCTIC OUTBREAK WILL DELIVER THE
COLDEST AIR OF THE SEASON TO THE AREA...ARRIVING ON SCHEDULE AS WE
ENTER THE HEART OF CLIMATOLOGICAL WINTER. THE UPPER LEVEL RIDGE IN
THE WEST IS PROJECTED TO BREAK-DOWN BY THE END OF THE PERIOD...AND
SHOULD ALLOW FOR SOME MODERATION INTO THE SECOND HALF OF NEXT WEEK.
THE GFS REMAINS SLIGHTLY FASTER THAN THE NON-NCEP GUID IN LIFTING
THE BASE OF THE ERN TROUGH NWD AT DAY 7-8. PRECIPITATION DURING THE
PERIOD WILL BE LIMITED/CONFINED MAINLY TO THE WESTERN HIGH
TERRAIN...WITH WEAK CLIPPERS REINFORCING THE COLD NWLY FLOW.
&&
.AVIATION /22Z THURSDAY THROUGH TUESDAY/...
MVFR CIGS WILL CONTINUE OVER MAINLY THE NORTHWEST MOUNTAINS
TONIGHT. KJST AND VCNTY WILL LIKELY SEE VFR FOR THE FIRST HALF OF
TONIGHT...FOLLOWED BY MVFR CIGS LATE.
LAKE MOISTURE CLIMBING THE HIGH TERRAIN OF THE NORTHWEST WILL
KEEP THE CHANCE OF SNOW SHOWERS AND LOCALLY REDUCED CONDITIONS IN
THE PICTURE INTO AT LEAST MID DAY FRIDAY...WITH IMPROVEMENT
EXPECTED BY FRIDAY AFTERNOON AND EVENING AS WINDS TURN MORE
SOUTHWESTERLY ON THE BACK SIDE OF A RETREATING HIGH.
OUTLOOK...
FRI...AM -SHSN/MVFR CIGS POSS W MTNS.
SAT...NO SIG WX EXPECTED.
SUN-TUE...SHSN/MVFR POSS W MTNS.
&&
.CTP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...LA CORTE/LAMBERT
NEAR TERM...LA CORTE/LAMBERT
SHORT TERM...LA CORTE
LONG TERM...STEINBUGL
AVIATION...LA CORTE/LAMBERT
AREA FORECAST DISCUSSION FOR SOUTHEAST SD/SOUTHWEST MN/NORTHWEST IA
NWS SIOUX FALLS SD
311 PM CST THU JAN 17 2013
.DISCUSSION.../ISSUED AT 311 PM CST/
WARM FRONT LIFTS NORTH TONIGHT GIVING WAY TO A MILD AND MOSTLY SUNNY
FRIDAY ACROSS THE AREA. FORECAST TONIGHT A BIT TRICKY WITH POTENTIAL
STRATUS ISSUES. MID LEVEL CLOUDS WILL CONTINUE TO STREAM ACROSS OUR
NORTH THROUGH THE NIGHT ASSOCIATED WITH MID LEVEL FRONTAL BOUNDARY.
HOWEVER THINK THE CWA WILL REMAIN DRY...OTHER THAN MAYBE AN ISOLATED
FLURRY ACROSS SOUTHWEST MINNESOTA. AREA OF STRATUS FROM SOUTH OF
SIOUX FALLS INTO EASTERN NEBRASKA CONTINUES TO DISSIPATE UNDER
DAYTIME HEATING. HOWEVER...CURRENT THINKING...BACKED BY THE RAP AND
NAM...IS THAT THIS AREA WILL REFORM AND EXPAND THIS EVENING INTO
TONIGHT. WITH SOUTHERLY BOUNDARY LAYER FLOW THIS WILL THEN EXPAND
AND COULD COVER MUCH OF THE CWA FOR A PERIOD TONIGHT. DRIER BOUNDARY
LAYER MOVING IN FROM THE SOUTHWEST WILL ALLOW THE STRATUS TO CLEAR
FROM SOUTHWEST TO NORTHEAST THROUGH THE NIGHT. COULD BE AREAS OF FOG
AS WELL. BEST CHANCE OF STAYING CLEAR THROUGH THE NIGHT WILL BE WEST
OF SIOUX CITY TO YANKTON UP TOWARDS GREGORY. LOW LEVEL JET INCREASES
TONIGHT...WHICH SHOULD KEEP A SOUTHERLY BREEZE GOING. THE BREEZE
COMBINED WITH POTENTIAL CLOUDS SHOULD KEEP LOWS ON THE WARM SIDE OF
GUIDANCE. GENERALLY AROUND 20 SOUTHWEST MINNESOTA TO LOW AND MID 20S
ELSEWHERE. LOWS WILL PROBABLY BE IN THE EVENING...WITH STEADY OR
RISING TEMPERATURES OVERNIGHT.
ANY STRATUS SHOULD EXIT THE CWA BY AROUND 12Z. COULD BE SOME CIRRUS
OVERHEAD DURING THE DAY...BUT OVERALL EXPECTING A MOSTLY SUNNY DAY.
KEPT HIGHS CLOSE TO THE ECMWF AND ECMWF MOS...AS THEY PERFORMED BEST
ON WEDNESDAY. LOOKING AT LOW AND MID 40S NORTH TO THE LOW AND MID
50S CLOSER TO THE MISSOURI RIVER. WITH 925MB TEMPERATURES
APPROACHING 10C IN OUR SOUTHWEST...WOULD NOT BE SURPRISED IF
SOMEPLACE IN NORTH CENTRAL NEBRASKA...OR ADJACENT AREAS OF GREGORY
AND CHARLES MIX COUNTIES COME CLOSE TO 60. /CHENARD
MAJOR PATTERN CHANGE EXPECTED TO BEGIN ON SATURDAY AS AN ARCTIC
BLAST DROPS SOUTHWARD INTO THE NORTHERN PLAINS. COLD FRONT SLATED TO
PUSH THROUGH THE FORECAST AREA DURING THE DAY...AND THE BIG QUESTION
IS HOW QUICKLY IT WILL ARRIVE. LARGE TEMPERATURE DISCREPANCIES
BETWEEN MODELS FOR SATURDAY HIGHS WITH A STAGGERING NEARLY 30 DEGREE
DIFFERENCE BETWEEN THE WARMEST AND COLDEST MODELS IN SIOUX FALLS.
THE GFS AND NAM ARE THE FASTEST WITH PULLING THE COLDER AIR INTO THE
FORECAST AREA WHILE THE ECMWF AND GEM PAINT A MUCH SLOWER
PROGRESSION AND DEPICT A MILD DAY ACROSS THE CWA. HAVE OPTED FOR A
MIDDLE GROUND SOLUTION WITH MIXING KEEPING TEMPERATURES ON THE
MILDER SIDE. EXPECT THE MISSOURI VALLEY TO REACH NEAR 40 RANGING TO
AROUND 30 AT OUR NORTHERN BORDER.
FRONTAL PASSAGE IS EXPECTED TO BE DRY...BUT STRONG NORTHWEST WINDS
IN ITS WAKE WILL PRODUCE SOME BRUTAL WIND CHILLS. WITH 925MB WINDS
UP AROUND 50 KT AND STRONG COLD AIR ADVECTION...WOULD NOT BE
SURPRISED TO SEE ADVISORY LEVEL WINDS. COLD AIR WILL QUICKLY DROP
SOUTH LATE EVENING INTO THE OVERNIGHT AND LOWS SATURDAY NIGHT WILL
BE IN THE SINGLE DIGITS ABOVE AND BELOW ZERO. WINDS WILL DECREASE ON
SUNDAY AS SURFACE HIGH PRESSURE QUICKLY SHUNTS SOUTHEAST OF THE
REGION...BUT DO NOT EXPECT MUCH RECOVERY OF TEMPERATURES. HIGHS WILL
ONLY BE IN THE SINGLE DIGITS AND TEENS FOR THE MAJORITY OF THE CWA.
A QUICK SHOT OF LIGHT SNOW WILL MOVE SOUTHEAST DURING THE DAY AHEAD
OF A REINFORCING SHOT OF COLD AIR. SNOW WOULD LIKELY BE BRIEF WITH
NOT MUCH MOISTURE TO WORK WITH...HOWEVER THE COLD TEMPERATURES
SHOULD PRODUCE UP TO AN INCH OF FLUFFY SNOW. NORTHERLY WINDS WILL
PICK UP ONCE AGAIN BEHIND THE FRONT AND WOULD DRIFT WHATEVER SNOW
FALLS ON SUNDAY. SUNDAY NIGHT WILL SEE SOME OF THE COLDEST
TEMPERATURES OF THE SEASON SO FAR WITH THE NORTHERN HALF DROPPING
INTO THE TEENS BELOW ZERO. FRIGID TEMPERATURES WILL CONTINUE INTO
MONDAY WITH HIGHS NEAR ZERO IN OUR NORTHEAST.
MODELS KEEP THE LARGE UPPER RIDGE OVER THE INTERMOUNTAIN WEST IN
PLACE INTO TUESDAY...WHICH LEAVES THE FORECAST AREA UNDER COOL
NORTHWEST FLOW. MODELS BRING A WEAK WAVE THROUGH THE FLOW AROUND THE
MONDAY NIGHT TO TUESDAY TIME FRAME...HOWEVER NOT A LOT OF CONFIDENCE
THAT THE CWA WILL SEE MUCH IMPACT. WILL LEAVE THE SLIGHT CHANCES
THAT THE LATEST ALLBLEND PRODUCED FOR NOW. WARMER WEATHER MAY RETURN
ON WEDNESDAY AND THURSDAY WITH THE RIDGE ADVANCING EASTWARD.
&&
.AVIATION.../FOR THE 18Z TAF ISSUANCE/
CURRENTLY SEEING VFR STRATUS OVER MUCH OF THE FORECAST AREA. HOWEVER
BAND OF IFR/LIFR STRATUS CONTINUES TO LINGER FROM YANKTON TO SIOUX
CITY AND SOUTH INTO EASTERN NEBRASKA. WEAK BOUNDARY LAYER FLOW
PREVENTING MUCH MOVEMENT...AND RAP SOUNDINGS SUGGEST DISSIPATION IS
UNLIKELY. THUS NOW THINKING THAT KSUX STAYS STUCK IN THE IFR STRATUS
THROUGH THE DAY AND INTO TONIGHT. WOULD NOT BE SURPRISED IF THE LIFR
CIGS CURRENTLY WEST OF SIOUX CITY POSSIBLY MOVE IN TONIGHT...BUT
WITH LOW CONFIDENCE ON TIMING AND CIG HEIGHT...WILL LEAVE THINGS IFR
FOR NOW. AREA OF MVFR STRATUS OVER NORTH CENTRAL SOUTH DAKOTA IS
BEGINNING TO MOVE BACK INTO OUR NORTHERN AREAS. RAP WOULD SUGGEST
THIS MOVES INTO KHON AND KFSD FOR A PERIOD THIS AFTERNOON..BEFORE
CLOUD LAYER FLOW TURNS SOUTHWESTERLY PUSHING IT BACK NORTH. WILL
HAVE TO MONITOR THIS THOUGH...AS KFSD WILL LIKELY BE RIGHT ON THE
EDGE OF THESE MVFR CIGS. OTHER CONCERN FOR KFSD IS THE IFR/LIFR
STRATUS TO THE SOUTH MENTIONED ABOVE. BASED ON SATELLITE...BELIEVE
THIS AREA IS NOT TOO FAR AWAY. AS BOUNDARY LAYER FLOW TURNS WEAK
SOUTHERLY THINKING THIS MOVES IN LATER THIS AFTERNOON OR EVENING.
THIS IS SHOWN BY THE RAP...WHICH EXPANDS THE CURRENT LOW STRATUS
DECK NORTHWARD...EVENTUALLY POSSIBLY EVEN REACHING KHON. KEPT KFSD
AND KHON AT LOW END MVFR FOR NOW...BUT THINKING A PERIOD OF IFR OR
LIFR IS VERY POSSIBLE TONIGHT...ESPECIALLY AT KFSD. BY LATER
TONIGHT...DRIER AIR WILL WORK IN FROM SOUTHWEST TO NORTHEAST...WITH
ALL TAF SITES BECOMING VFR BY MORNING. /CHENARD
&&
.FSD WATCHES/WARNINGS/ADVISORIES...
SD...NONE.
MN...NONE.
IA...NONE.
NE...NONE.
&&
$$
AREA FORECAST DISCUSSION FOR SOUTHEAST SD/SOUTHWEST MN/NORTHWEST IA
NWS SIOUX FALLS SD
1150 AM CST THU JAN 17 2013
.DISCUSSION.../ISSUED AT 955 AM CST/
A COUPLE AREAS OF CLOUDS ACROSS THE CWA AT THIS TIME...WITH A SMALL
WINDOW OF CLEARING FROM SIOUX FALLS TO MARSHALL. THINK THIS AREA
WILL GIVE WAY TO INCREASING CLOUDS...AS STRATUS IN CENTRAL SOUTH
DAKOTA MOVES BACK IN. MEANWHILE...THERE IS A SECOND AREA OF LOWER
CLOUDS CLOSER TO THE MISSOURI RIVER...FROM YANKTON TO SIOUX CITY
AND SOUTH DOWN INTERSTATE 29 TOWARDS OMAHA AND LINCOLN NEBRASKA.
WILL HAVE TO WATCH AND SEE WHAT HAPPENS WITH THIS THROUGH THE REST
OF THE MORNING. RAP SUGGESTS IT MAY ACTUALLY EXPAND...AND WITH
BOUNDARY LAYER FLOW BECOMING WEAK SOUTHWESTERLY...IT MAY LINGER
ACROSS OUR NORTHWEST IOWA COUNTIES. AS FAR AS TEMPERATURES
GO...WOULD NOT BE SURPRISED IF AREAS FROM WEST OF YANKTON TO GREGORY
END UP A COUPLE DEGREES WARMER...ESPECIALLY IF IT REMAINS MOSTLY
SUNNY. ALSO...AREAS FROM SIOUX FALLS TO SIOUX CITY AND EAST...MAY
END UP A FEW DEGREES COOLER THAN CURRENT FORECAST IF CLOUDS HANG
AROUND LIKE THE RAP IS SUGGESTING. GIVEN CLOUD COVER
UNCERTAINTY...WILL LEAVE HIGHS ALONE FOR NOW AND ADJUST AS NEED BE
AS CLOUD AND TEMPERATURE TRENDS BECOME MORE APPARENT LATER THIS
MORNING. /CHENARD
.PREVIOUS DISCUSSION.../ISSUED AT 305 AM CST/
A CHILLY START TO THE DAY AS A SHALLOW ARCTIC AIR MASS HAS STALLED
OVER THE EASTERN HALF OF THE CWA. THIS WILL MODIFY THROUGH THE DAY
LEADING TOWARDS HIGH TEMPERATURES A BIT ABOVE NORMAL...BUT NOT AS
WARM AS YESTERDAY. CLOUDS AS WELL AS THE COOLER START WILL BE THE
MAIN REASONS. REGARDLESS...PLANNING ON HIGHS FROM NEAR 40 ALONG THE
MISSOURI RIVER TO THE MID 20S IN SOUTHWEST MINNESOTA.
A STRONG SOUTHERLY PRESSURE GRADIENT WILL DEVELOP OVERNIGHT LEADING
TOWARDS A NON DIURNAL TEMPERATURE PROFILE. LOWS IN MOST SPOTS WILL
OCCUR BETWEEN ABOUT 2Z AND 6Z...THEN RISE AFTER. EXPECTING LOWS IN
THE MID TEENS TO LOWER 20S BUT 12Z FRIDAY TEMPERATURES LIKELY TO BE
BETWEEN 25 AND 30 DEGREES IN MOST LOCATIONS WITH A BIT OF A BREEZY
SOUTH WIND.
THIS WILL LEAD INTO A VERY WARM FRIDAY...ESPECIALLY LOOKING AT WHAT
HAPPENED ACROSS THE AREA TODAY. NOT MUCH INT HE WAY OF CLOUD COVER
AND WINDS TURNING FROM THE SOUTHWEST TO THE WEST AND NORTHWEST
THROUGH THE DAY SUPPORTS MIXY AND MILD CONDITIONS. WITH 925MB
TEMPERATURES WELL INTO THE SINGLE DIGITS...ESPECIALLY SOUTH...HIGHS
SHOULD RANGE FROM THE LOWER 40S NORTH TO 50 TO 55 SOUTH.
MILD WESTERLY FLOW WILL REMAIN IN PLACE THROUGH FRIDAY NIGHT INTO
SATURDAY MORNING AHEAD OF A STRONG PUSH OF COLD AIR. TEMPERATURES
SHOULD ONLY FALL INTO THE 20 TO 25 DEGREE RANGE FRIDAY NIGHT THEN
QUICKLY WARM INTO THE MID 30S TO LOWER 40S ON SATURDAY AHEAD OF THE
COLD FRONT. IF THE FRONT IS JUST A FEW HOURS SLOWER HIGHS WILL
LIKELY BE ANOTHER 5 DEGREES WARMER SO TIMING OF THIS BOUNDARY WILL
BE VERY IMPORTANT. HAVE TEMPERATURES TANKING LATE AFTERNOON AND
EVENING AS THE FRONT BARRELS THROUGH. AT SOME POINT IN TIME MAY NEED
A WIND ADVISORY FOR THE AREA AND POSSIBLY A WIND CHILL ADVISORY IN
THE NORTHERN CWA.
IN THE LATTER PERIODS(SUN/THU)...NOT MUCH IN THE WAY OF CHANGES AS
BELOW NORMAL TEMPERATURES STILL THE MAIN ISSUE. A VERY STRONG RIDGE
WILL BE IN PLACE OVER THE WESTERN UNITED STATES WHICH WILL ALLOW A
NORTHERLY ORIENTED JET TO BE IN PLACE OVER THE NORTHERN PLAINS. THIS
WILL MAKE IT DIFFICULT TO BREAK OUT OF THE COLD AIR DURING THE
PERIOD. WILL CONTINUE THE CHANCE FOR SNOW ON SUNDAY AHEAD OF THE
VERY STRONG COLD FRONT. NOT EXPECTING A LOT OF ACCUMULATION BUT
MIGHT BE ENOUGH TO ADD A LITTLE TO WHAT IS OUT THERE. SUNDAY NIGHT
INTO MONDAY EVENING LIKELY TO BE THE COLDEST 24 HOUR PERIOD THIS
SEASON SO FAR WITH SOME TYPE OF COLD HEADLINE ANTICIPATED. AFTER
THIS MODELS NOT REAL AGREEABLE BUT NOT TERRIBLE. LOOKS LIKE A SLOW
MODERATING TREND THROUGH THE WEEK. /08
&&
.AVIATION.../FOR THE 18Z TAF ISSUANCE/
CURRENTLY SEEING VFR STRATUS OVER MUCH OF THE FORECAST AREA. HOWEVER
BAND OF IFR/LIFR STRATUS CONTINUES TO LINGER FROM YANKTON TO SIOUX
CITY AND SOUTH INTO EASTERN NEBRASKA. WEAK BOUNDARY LAYER FLOW
PREVENTING MUCH MOVEMENT...AND RAP SOUNDINGS SUGGEST DISSIPATION IS
UNLIKELY. THUS NOW THINKING THAT KSUX STAYS STUCK IN THE IFR STRATUS
THROUGH THE DAY AND INTO TONIGHT. WOULD NOT BE SURPRISED IF THE LIFR
CIGS CURRENTLY WEST OF SIOUX CITY POSSIBLY MOVE IN TONIGHT...BUT
WITH LOW CONFIDENCE ON TIMING AND CIG HEIGHT...WILL LEAVE THINGS IFR
FOR NOW. AREA OF MVFR STRATUS OVER NORTH CENTRAL SOUTH DAKOTA IS
BEGINNING TO MOVE BACK INTO OUR NORTHERN AREAS. RAP WOULD SUGGEST
THIS MOVES INTO KHON AND KFSD FOR A PERIOD THIS AFTERNOON..BEFORE
CLOUD LAYER FLOW TURNS SOUTHWESTERLY PUSHING IT BACK NORTH. WILL
HAVE TO MONITOR THIS THOUGH...AS KFSD WILL LIKELY BE RIGHT ON THE
EDGE OF THESE MVFR CIGS. OTHER CONCERN FOR KFSD IS THE IFR/LIFR
STRATUS TO THE SOUTH MENTIONED ABOVE. BASED ON SATELLITE...BELIEVE
THIS AREA IS NOT TOO FAR AWAY. AS BOUNDARY LAYER FLOW TURNS WEAK
SOUTHERLY THINKING THIS MOVES IN LATER THIS AFTERNOON OR EVENING.
THIS IS SHOWN BY THE RAP...WHICH EXPANDS THE CURRENT LOW STRATUS
DECK NORTHWARD...EVENTUALLY POSSIBLY EVEN REACHING KHON. KEPT KFSD
AND KHON AT LOW END MVFR FOR NOW...BUT THINKING A PERIOD OF IFR OR
LIFR IS VERY POSSIBLE TONIGHT...ESPECIALLY AT KFSD. BY LATER
TONIGHT...DRIER AIR WILL WORK IN FROM SOUTHWEST TO NORTHEAST...WITH
ALL TAF SITES BECOMING VFR BY MORNING. /CHENARD
&&
.FSD WATCHES/WARNINGS/ADVISORIES...
SD...NONE.
MN...NONE.
IA...NONE.
NE...NONE.
&&
$$