Forecast Discussions mentioning any of
"HRRR" "RAP" "RR" "RUC13" "RUC" received at GSD on 11/30/12
AREA FORECAST DISCUSSION
NWS SACRAMENTO CA
439 PM PST THU NOV 29 2012
.SHORT TERM DISCUSSION...
WATER VAPOR IMAGERY SHOWS AN IMPRESSIVE UPPER LEVEL LOW OFF THE
COAST WITH MOISTURE STREAMING INTO NORTHERN CALIFORNIA. A
SHORTWAVE WITH A SURFACE COLD FRONT IS GRADUALLY SPREADING
PRECIPITATION OVER THE COAST AND INLAND. IR SATELLITE INDICATES
COLD CLOUD TOP ENHANCEMENT OVER THE AREA. THIS SYSTEM HAS A STRONG
PACIFIC MOISTURE TAP WITH THE 18Z GFS PROJECTING PW VALUES AROUND
1.2 INCHES EXTENDING INLAND OVER THE FORECAST AREA TONIGHT. THIS
IS AN ATMOSPHERIC RIVER PATTERN TRANSPORTING MOISTURE IN FROM THE
CENTRAL PACIFIC. THIS PATTERN WILL CONTINUE THROUGH THE WEEKEND
WITH MULTIPLE DISTURBANCES BRINGING PERIODS OF MODERATE TO HEAVY
RAIN. THERE WILL BE IMPRESSIVE QUANTITIES OF PRECIPITATION THROUGH
THE DAY SUNDAY...ESPECIALLY WITH OROGRAPHIC LIFT IN THE NORTHERN
SIERRA AND NORTHERN MOUNTAINS. THIS RELATIVELY MILD SYSTEM WILL
HAVE SIGNIFICANT SNOWFALL CONFINED TO ABOVE 7000 FEET. SEVERAL
FEET OF SNOW ARE POSSIBLE FOR HIGH PEAKS 8500 FEET...WITH 8 TO 12
INCHES TOTAL AROUND PASS LEVEL.
PRECIPITATION HAS SPREAD OVER THE MOUNTAINS AND VALLEY NORTH OF
STOCKTON. THE FRONT WAS A LITTLE SLOWER THAN EXPECTED WHICH
DELAYED THE ONSET OF RAIN BY SEVERAL HOURS. RADAR AND SURFACE
OBSERVATIONS SHOW THE HEAVIEST PRECIPITATION IS CURRENTLY OVER THE
NORTHERN SACRAMENTO VALLEY AND COASTAL MOUNTAINS. THE HRRR AND WRF
MODELS SHOW PRECIPITATION INTENSITY INCREASING OVERNIGHT AND
SPREADING OVER THE AREA. THE NORTHERN SAN JOAQUIN WILL SEE LESS
PRECIPITATION THAN THE VALLEY TO THE NORTH.
MAIN ISSUE CONTINUES TO BE THE THREAT OF FLOODING AND FOR DEBRIS
FLOWS IN RECENTLY BURNED AREAS...SO A FLOOD WATCH CONTINUES THROUGH
SUNDAY ACROSS THE CWA. THE HEAVIEST PERIODS OF RAINFALL ARE FORECAST
FOR OVERNIGHT TONIGHT AND AGAIN SATURDAY NIGHT INTO SUNDAY.
CURRENT PROJECTIONS CONTINUE TO SHOW THE UPPER SACRAMENTO RIVER IS
EXPECTED TO HAVE LOCATIONS EXCEEDING MONITOR STAGE THIS WEEKEND.
TEHAMA BRIDGE IS EXPECTED TO EXCEED FLOOD STAGE FRIDAY AFTERNOON
AND AGAIN BY SUNDAY SO A RIVER FLOOD WARNING HAS BEEN ISSUED THERE.
SMALL STREAMS ACROSS THE NORTHERN PORTION OF THE FORECAST AREA
(NORTH OF I80) ALSO MAY SEE RAPID RISES WITH FLOODING BECOMING
INCREASINGLY LIKELY THROUGH THE WEEKEND. A FLOOD WARNING FOR URBAN
AREAS AND SMALL STREAMS HAS BEEN ISSUED FOR THAT AREA.
ANOTHER IMPACT INCLUDES WINDY CONDITIONS THROUGH THE
WEEKEND WITH A WIND ADVISORY CONTINUING INTO SUNDAY. THERE WILL
BE BRIEF LULLS IN THE WIND AT TIMES BUT CONDITIONS WILL BE
WINDY/BREEZY MUCH OF THE TIME.
A WINTER STORM WARNING BEGINS 4 PM THIS AFTERNOON AND CONTINUES TO
4 PM PST FRIDAY ABOVE 7000 FEET FOR THE WEST SLOPE NORTHERN SIERRA
NEVADA AND THE MOUNTAINS OF WESTERN PLUMAS COUNTY/LASSEN PARK.
SIGNIFICANT SNOW ACCUMULATION WILL BE POSSIBLE AT THE HIGHEST
ELEVATIONS OF THE NORTHERN SIERRA TONIGHT INTO FRIDAY BEFORE SNOW
LEVELS RISE OVER THE WEEKEND. EK
.EXTENDED DISCUSSION (MONDAY THROUGH THURSDAY)
FRONTAL SYSTEM WILL SHIFT EAST OF THE FORECAST AREA EARLY MONDAY
MORNING. HOWEVER...ANOTHER DEEP MOISTURE PLUME WILL DEVELOP OVER
THE EASTERN PACIFIC AS UPPER LOW DROPS SOUTH FROM THE GULF OF
ALASKA. THIS LOW WILL DEEPEN THE TROUGH AND PUSH DEEP MOISTURE
INTO NORTHERN CALIFORNIA LATE MONDAY NIGHT AND TUESDAY. THE GFS IS
MORE AGGRESSIVE WITH MOISTURE WITH THIS SYSTEM VERSUS GFS. HAVE
RAISED POPS DURING THIS PERIOD AS MODELS SHOW GOOD AGREEMENT WITH
GENERAL PATTERN AND TIMING. SHOWER CHANCES CONTINUE ON WEDNESDAY
AS TROUGH MOVES THROUGH WITH LINGERING MOISTURE AND
INSTABILITY...ALTHOUGH MOISTURE VALUES ARE LOWER VERSUS TUESDAY. A
DRIER NORTHWEST FLOW IS THEN PROGGED TO DEVELOP INTO THE WEEKEND
AS RIDGE DEVELOPS OVER THE PACIFIC.
&&
.AVIATION...
A BAND OF MODERATE TO HEAVY PRECIP IS MOVING INTO THE AREA THIS
AFTERNOON AT THE LEADING EDGE OF ANOTHER PACIFIC STORM. SHOWERY
PRECIP AND MVFR EXPECTED TO REACH SAC METRO TAF SITES BY 0OZ WITH
THE MAIN BAND OF PRECIP AND MVFR/IFR MOVING IN AROUND 06Z AND
CONTINUING THROUGH THE NIGHT. CENTRAL VALLEY WINDS WILL INCREASE
AS THE HEAVY PRECIP MOVES IN...WITH GUSTS INCREASING TO AROUND
30KTS.
IN THE FOOTHILLS AND MOUNTAINS...WIDESPREAD IFR WILL MOVE IN THIS
EVENING AND OVERNIGHT WITH LOW CIGS AND WINDY CONDITIONS. OVER
SIERRA RIDGETOPS...WIND GUSTS APPROACH 65 TO 75 KNOTS OVERNIGHT.
-DVC
&&
.STO WATCHES/WARNINGS/ADVISORIES...
FLOOD WATCH THROUGH SUNDAY AFTERNOON BURNEY BASIN / EASTERN
SHASTA COUNTY...CARQUINEZ STRAIT AND DELTA...CLEAR LAKE/SOUTHERN
LAKE COUNTY...MOTHERLODE...MOUNTAINS SOUTHWESTERN SHASTA COUNTY
TO NORTHERN LAKE COUNTY...NORTHEAST FOOTHILLS/SACRAMENTO
VALLEY...NORTHERN SAN JOAQUIN VALLEY...SHASTA LAKE AREA /
NORTHERN SHASTA COUNTY...SOUTHERN SACRAMENTO VALLEY...WEST SLOPE
NORTHERN SIERRA NEVADA...WESTERN PLUMAS COUNTY/LASSEN PARK.
FLOOD WATCH THROUGH MONDAY AFTERNOON CENTRAL SACRAMENTO VALLEY...
NORTHERN SACRAMENTO VALLEY
FLOOD WARNING FOR URBAN AREAS AND SMALL STREAMS CONTINUES THROUGH
315 PM FOR THE MOUNTAINS AND VALLEY NORTH OF INTERSTATE 80.
WIND ADVISORY UNTIL 10 AM PST SUNDAY BURNEY BASIN / EASTERN SHASTA
COUNTY...CENTRAL SACRAMENTO VALLEY...CLEAR LAKE/SOUTHERN LAKE
COUNTY...MOUNTAINS SOUTHWESTERN SHASTA COUNTY TO NORTHERN LAKE
COUNTY...NORTHEAST FOOTHILLS/SACRAMENTO VALLEY...NORTHERN
SACRAMENTO VALLEY...SHASTA LAKE AREA / NORTHERN SHASTA COUNTY...
WESTERN PLUMAS COUNTY/LASSEN PARK.
WIND ADVISORY UNTIL 4 PM PST SUNDAY CARQUINEZ STRAIT AND DELTA...
MOTHERLODE...NORTHERN SAN JOAQUIN VALLEY...SOUTHERN SACRAMENTO
VALLEY...WEST SLOPE NORTHERN SIERRA NEVADA.
WINTER STORM WARNING UNTIL 4 PM PST FRIDAY ABOVE 7000 FEET FOR
THE WEST SLOPE NORTHERN SIERRA NEVADA AND THE MOUNTAINS OF WESTERN
PLUMAS COUNTY.
&&
$$
AREA FORECAST DISCUSSION
NWS DENVER/BOULDER CO
957 AM MST WED NOV 28 2012
.UPDATE...OVERALL...CURRENT FORECASTS SEEM ON TRACK. WAVE CLOUD
CURRENTLY ACROSS MUCH OF FOOTHILLS AND URBAN CORRIDOR WHICH WRF
SYNTHETIC SATELLITE IMAGERY SHOWS CONTINUING INTO THE EVENING. AS
NOTED IN EARLIER DISCUSSION...THE AMOUNT OF CLOUD COULD LIMIT THE
WARMUP DESPITE THE 2 DEGREE CELSIUS TEMPERATURE INCREASE AT 700
MB. MAY NEED TO SHAVE A FEW MORE DEGREES OF THE MAX TEMPS.
WESTERLY FLOW ALOFT TO PREVAIL THROUGH TONIGHT...WITH WINDS A BIT
GUSTY ACROSS THE MOUNTAINS AND HIGHER FOOTHILLS. COULD SEE AN
INCREASE THIS EVENING AS SURFACE TROUGH DEVELOPS OVER THE EASTERN
PLAINS.
&&
.AVIATION...WINDS STILL A BIT VARIABLE ACROSS AREA AIRPORTS WITH
DECREASING SPEEDS. SOME HINTS OF WINDS TRYING TO GO LIGHT
NORTHWEST...THOUGH SOUTHERLY DIRECTION SEEMS TO BE PREVAILING.
LATEST RUC SHOWING THE DEVELOPMENT OF A WEAK ANTICYCLONE JUST NORTH
OF DIA BY 18Z...WITH LIGHT NORTHEAST WINDS AT DIA AND APA AND
WESTERLY AT BJC. STILL A BIT DIFFICULT TO DETERMINE IF THE
SOUTHERLY GRADIENT WILL PERSIST OR ANTICYCLONE PREVAILS. FOR NOW
WILL CONTINUE WITH THE CURRENT TAF TRENDS...BUT MAY NEED TO LOWER
SPEEDS A BIT.
&&
.FIRE WEATHER...FIRE DANGER WILL REMAIN ELEVATED TODAY...BUT NO
FIRE WEATHER HILITES EXPECTED. GUSTY WINDS WILL AGAIN PREVAIL...
MAINLY ACROSS MOUNTAINS AND NORTHERN FOOTHILLS. SHOULD BE LIGHTER
THAN YESTERDAY. ALTHOUGH THE AIRMASS WILL REMAIN DRY...HUMIDITY
WILL BE SLIGHTLY HIGHER THAN YESTERDAY`S READINGS.
&&
.PREV DISCUSSION... /ISSUED 356 AM MST WED NOV 28 2012/
SHORT TERM...AN UPPER RIDGE AXIS CURRENTLY OVERHEAD WILL BE
SLIGHTLY FLATTENED AND PUSHED EAST AS A VERY WEAK DISTURBANCE IN
THE FLOW MOVES IN. HIGH LEVEL MOISTURE HAS REFORMED YESTERDAYS
WAVE CLOUD OVER MOST OF THE FRONT RANGE AREA. LOOKING UPSTREAM AT
WATER VAPOR...EXPECT THE WAVE CLOUD TO HANG ON THROUGH MOST OF THE
DAY WITH INCREASING HIGH CLOUD COVER ELSEWHERE AS WELL. THIS WILL
LIMIT THE HEATING WE SEE TODAY...THOUGH WITH 700 MB TEMPERATURES
INCREASING BY ABOUT 2 DEGREES C...STILL EXPECT HIGHS IN THE UPPER
50S TO LOWER 60 FOR THE PLAINS AND IN THE 40S TO 50S IN THE HIGH
COUNTRY. WILL HAVE TO KEEP AN EYE ON TEMPERATURES THROUGH THE DAY
TO SEE IF THE CLOUDS DAMPEN THE HIGHS MORE THAN WHAT IS IN THERE.
WINDS WILL REMAIN GUSTY IN THE MOUNTAINS AND HIGH FOOTHILLS...BUT
EXPECTING LIGHTER SPEEDS COMPARED TO YESTERDAY.
TONIGHT...A SURFACE TROUGH WILL BE DEEPENING OVER THE PLAINS TO
INCREASE THE WEST WINDS COMING OUT OF THE MOUNTAINS AND
FOOTHILLS. THIS ALONG WITH THE SLIGHT WARMING ALONG WILL MODERATE
MINIMUM TEMPERATURES TONIGHT.
LONG TERM...NOT MUCH HAS CHANGED WITH REGARD TO THE FORECAST
THROUGH THIS WEEKEND. THE DEEP TROUGH IN THE EASTERN PACIFIC WILL
KEEP FLAT RIDGING IN PLACE WITH GENERALLY MODERATE WEST/SOUTHWEST
FLOW ALOFT ACROSS COLORADO THROUGH SUNDAY. THERE ARE STILL A
COUPLE OF WEAK WAVES RIPPLING ACROSS THE STATE. THE FIRST WAVE
SHOULD BRING LITTLE MORE THAN A FEW MID/HIGH CLOUDS LATE TONIGHT
INTO EARLY THURSDAY. THEN ANOTHER LATE FRIDAY INTO FRIDAY
NIGHT...WITH A BIT MORE MOISTURE ASSOCIATED WITH THIS ONE. AS A
RESULT...HAVE ADDED JUST A SLIGHT CHANCE OF SNOW SHOWERS TO THE
NORTHERN MOUNTAIN AREAS FRIDAY NIGHT. THE PASSAGE OF THIS WAVE
WILL BRING ENHANCED SUBSIDENCE AND MIXING BY SATURDAY...SO
INCREASED WINDS A FEW MPH FROM GOING FORECAST. SLIGHT COOLING
ALOFT MAY BE OFFSET BY BETTER MIXING SO TEMPERATURES WILL LIKELY
REMAIN ABOUT 15 DEGREES ABOVE NORMAL.
SUNDAY IS STILL SHAPING UP TO BE THE WARMEST DAY WITH 700 MB
TEMPERATURES ADVERTISED TO REACH THE 6-9C RANGE. DEPENDING ON
AMOUNT OF SUNSHINE AND DOWNSLOPE...WE COULD STILL SEE HIGHS OF
70F OR MORE AND INCREASING FIRE DANGER WITH STRONGER SOUTH/
SOUTHWESTERLY FLOW DEVELOPING.
BY SUNDAY NIGHT/MONDAY...A STRONGER PIECE OF ENERGY...BASICALLY
LEFTOVERS OF THE EASTERN PACIFIC TROUGH...IS EXPECTED TO REACH
COLORADO. Q-G VERTICAL MOTION AND MOISTURE SHOULD BE ENOUGH TO
BRING AT LEAST SOME LIGHT SNOW SHOWERS TO THE MOUNTAINS.
MEANWHILE...PLAINS WILL LIKELY REMAIN DRY WITH CONTINUED
DOWNSLOPING FLOW. GUSTY WINDS ARE ALSO EXPECTED TO DEVELOP IN THE
WAKE OF THE TROUGH PASSAGE SO BOOSTED WIND SPEEDS FOR MONDAY.
TEMPERATURES WILL ALSO TURN COOLER BUT SHOULD STILL AVERAGE A FEW
DEGREES ABOVE NORMAL BOTH MONDAY AND TUESDAY.
AVIATION...DRAINAGE WINDS BEGINNING TO STRENGTHEN A BIT OVER KDEN
AND KAPA. WINDS SHOULD DECREASE IN SPEED THROUGH THE MORNING HOURS
AND BECOME LIGHT SOUTHEAST. WINDS TONIGHT WILL AGAIN BE AN
ENHANCED DRAINAGE PATTERN AS A SURFACE TROUGH DEEPENS. VFR
CONDITIONS THROUGH THURSDAY MORNING.
FIRE WEATHER...GUSTY WINDS AND LOW HUMIDITIES ARE EXPECTED AGAIN
TODAY...MAINLY OVER THE NORTHERN FOOTHILLS. HOWEVER THE WINDS WILL
BE SLIGHTLY LIGHTER AND HUMIDITIES NOT AS LOW COMPARED TO
YESTERDAY. FIRE DANGER WILL BE ELEVATED...BUT DO NOT EXPECT TO
REACH CRITERIA VALUES FOR AN EXTENDED PERIOD SO ISSUED NO
HIGHLIGHT.
&&
.BOU WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...D-L
LONG TERM....BARJENBRUCH
AVIATION...D-L
AREA FORECAST DISCUSSION
NWS TAUNTON MA
ISSUED BY NATIONAL WEATHER SERVICE UPTON NY
949 AM EST WED NOV 28 2012
.SYNOPSIS...
DRIER AND UNSEASONABLY COLD WEATHER ARRIVES LATE TODAY AND LINGERS
THROUGH FRIDAY. A WARM FRONT WILL BRING MUCH MILDER WEATHER FOR
EARLY NEXT WEEK...WITH A CHANCE FOR SOME RAIN LATE SUNDAY INTO
EARLY MONDAY.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
FORECAST ON TRACK THIS MORNING.
MINOR TWEAKS TO BRING TEMPERATURES BACK IN LINE WITH OBSERVED
TRENDS. 28/06Z GFS/NAM AND 28/10Z RAP ALL INDICATE POTENTIAL FOR
OCEAN-EFFECT PRECIPITATION TO DEVELOP IN THE NORTHEAST FLOW ON THE
BACKSIDE OF THE DEPARTING LOW PRESSURE. MADE MINOR TWEAKS TO POPS
TO REFLECT THIS THOUGHT.
PREVIOUS DISCUSSION...
EXPECT LEFTOVER PRECIP ACROSS SE MA...CAPE COD AND THE ISLANDS TO
PUSH OFFSHORE BY 13Z-14Z AS LOW PRES PUSHES OFFSHORE. MOST OF THE
HIGH CLOUDS HAVE MOVED OFFSHORE AS SEEN ON IR SATELLITE. STILL SEE
LOWER CLOUDS ACROSS MOST AREAS AT 09Z. SOME LEFTOVER SHOWERS MAY
LINGER ALONG THE E COAST THROUGH MIDDAY...THOUGH SHOULD SHIFT
OFFSHORE DURING THE AFTERNOON. CLOUDS WILL LIKELY LINGER ACROSS
CENTRAL AND EASTERN AREAS THROUGH A GOOD PORTION OF THE DAY...
WHILE THEY BREAK ACROSS THE WEST AS HIGH PRES RIDGE BEGINS TO
BUILD ACROSS THE REGION. MAY SEE SOME GUSTY NW WINDS ACROSS THE E
COAST THIS MORNING...THEN WILL DIMINISH.
EXPECTING DAYTIME HIGHS MAINLY IN THE MID-UPPER 30S ACROSS S
NH...RANGING TO THE MID 40S ALONG THE S COAST.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH 6 PM THURSDAY/...
TONIGHT...
HIGH PRESSURE WILL BUILD ACROSS THEN TO THE S OF THE REGION DURING
THE NIGHT. PRES GRADIENT WILL INCREASE AS SHOT OF COLDER AIR WILL
WORK IN DURING THE NIGHT...SO WILL SEE SOME WIND GUSTS PICKING UP
MAINLY AFTER MIDNIGHT ALONG THE IMMEDIATE E COAST AS WELL AS THE
CAPE AND ISLANDS. EXPECT OVERNIGHT LOWS MAINLY IN THE 20S...EXCEPT
THE LOWER-MID 30S ACROSS THE MID AND OUTER CAPE AND ISLANDS.
THURSDAY...
HIGH PRES SETTLES ACROSS THE MID ATLC STATES...WINDS WILL DIMINISH
AS THEY BACK TO THE W AND SW DURING THE AFTERNOON. EXPECT DRY
CONDITIONS WITH THE HIGH TO THE S. DAYTIME HIGHS WILL BE IN THE
UPPER 30S TO MID 40S...WHICH WILL STILL BE UP TO 5 DEGREES BELOW
SEASONAL NORMALS.
&&
.LONG TERM /THURSDAY NIGHT THROUGH TUESDAY/...
HIGHLIGHTS...
* DRY AND UNSEASONABLY COLD THURSDAY AND FRIDAY
* A FEW PASSING RAIN/SNOW SHOWERS POSSIBLE SATURDAY...BUT NOT A
WASHOUT
* MUCH MILDER EARLY NEXT WEEK WITH SOME RAIN SHOWERS POSSIBLE LATE
SUNDAY/EARLY MON
28/00Z GUIDANCE CONTINUES TO BE IN VERY GOOD AGREEMENT OVER THIS
PORTION OF THE FORECAST. JUST ABOUT ALL MODELS MAINTAIN A
PROGRESSIVE MID-LEVEL FLOW PATTERN UNTIL THE MIDDLE OF NEXT WEEK.
AS SUCH EXPECTING ONLY WEAK SYNOPTIC SYSTEMS TO IMPACT OUR REGION
AT TIMES...MAINLY FRONTS AS THE PARENT LOW PRESSURES STAY WELL
AWAY FROM OUR REGION.
DETAILS...
THURSDAY NIGHT AND FRIDAY...A FAIRLY STRONG COLD FRONT WILL MOVE
THROUGH THE REGION...BUT IT APPEARS TOO DRY FOR ANY PRECIPITATION.
THIS FRONT WILL RESULT IN THE COLDEST WEATHER SO FAR THIS SEASON.
A STRONG HIGH PRESSURE OVER EASTERN CANADA WILL RESULT IN
NORTHERLY SURFACE WINDS FRIDAY. THIS SHOULD RESULT IN POOR MIXING
AND KEEP THE SHALLOW COLD AIR IN PLACE.
SATURDAY...HIGH PRESSURE OVER QUEBEC WILL SLOWLY MOVE EAST INTO
THE CANADIAN MARITIMES AS A WARM FRONT TRIES TO APPROACH THE
REGION. THIS FRONT MAY BE ENOUGH TO TRIGGER A FEW RAIN/SNOW
SHOWERS...BUT CERTAINLY NOT EXPECTING A WASHOUT OR A SIGNIFICANT
PRECIPITATION EVENT WITH SUCH DRY LOW LEVELS. MAY HAVE TO WATCH
FOR SOME SLICK SPOTS ON THE ROADS IF THERE ENDS UP BEING SOME
LIGHT FROZEN PRECIPITATION...BUT THAT REMAINS UNCERTAIN AT THIS
TIME.
SUNDAY THROUGH TUESDAY...MUCH MILDER MID-LEVEL TEMPERATURES
SHOULD ARRIVE BEHIND A WARM FRONT....RESULTING IN SIGNIFICANTLY
MILDER TEMPERATURES EARLY NEXT WEEK. HIGHS SHOULD TOP OUT WELL
INTO THE 40S IF NOT THE 50S OVER THIS TIME. A FRONT MAY BRING A
ROUND OF RAIN SHOWERS TO THE REGION SOMETIME LATE SUNDAY INTO
EARLY MONDAY...BUT THE REST OF THE TIME LOOKS DRY.
&&
.AVIATION /15Z WEDNESDAY THROUGH SUNDAY/...
FORECASTER CONFIDENCE LEVELS...
LOW...LESS THAN 30 PERCENT
MODERATE...30 PERCENT TO 60 PERCENT
HIGH...GREATER THAN 60 PERCENT
OVERVIEW...MODERATE CONFIDENCE TODAY...HIGH CONFIDENCE TONIGHT
AND THURSDAY.
TODAY...MVFR CIGS MAY LINGER ACROSS CAPE COD AND THE ISLANDS
THROUGH MIDDAY. MAY ALSO SEE AREAS OF IFR CONDITIONS TOWARD EAST
COAST THIS MORNING IN OCEAN-EFFECT SHOWERS. MAY SEE N-NW GUSTS
AROUND 20 KT ALONG E COAST DURING THE AFTERNOON.
TONIGHT AND THURSDAY...
MAINLY VFR CONDITIONS. W-NW WINDS GUSTING TO AROUND 25 KT ACROSS E
COASTAL AREAS LATE TONIGHT AND EARLY THU...THEN BACKING TO W-SW
AND DIMINISHING.
KBOS TAF...HIGH CONFIDENCE IN TRENDS BUT MODERATE CONFIDENCE IN
TIMING.
KBDL TAF...MODERATE TO HIGH CONFIDENCE. EXPECT VFR CONDITIONS
THROUGH THU WITH FEW-SCT MID AND HIGH CLOUDS.
OUTLOOK...THURSDAY NIGHT THROUGH SUNDAY...
HIGH CONFIDENCE IN MAINLY VFR CONDITIONS. MAY SEE A PERIOD OF
MVFR CONDITIONS SATURDAY AS A WARM FRONT WORKS TOWARD THE REGION
WITH A FEW RAIN/SNOW SHOWERS. ANOTHER SHOT AT MVFR CONDITIONS WILL
BE LATE SUNDAY/SUNDAY NIGHT WITH A ROUND OF RAIN SHOWERS AHEAD OF
A COLD FRONT.
&&
.MARINE...
MODERATE TO HIGH CONFIDENCE.
TODAY...EXPECT WINDS TO BACK TO N-NW DURING THE DAY AS HIGH PRES
BUILDS OUT OF THE APPALACHIANS. WILL SEE SOME GUSTS UP TO 20-25 KT
ACROSS THE EASTERN WATERS EARLY...THEN WILL DIMINISH. SEAS WILL
REMAIN AOA 5 FT...SO HAVE KEPT SMALL CRAFT GOING.
TONIGHT-THURSDAY...NW WINDS WILL INCREASE AS COLDER AIR WORKS ACROSS
THE WATERS LATE TONIGHT INTO THURSDAY MORNING. EXTENDED THE SMALL
CRAFT THROUGH THURSDAY. WAVE MODELS INDICATING AN INCREASE IN
SEAS...POSSIBLY UP TO 7-8 FT...ON THE OUTER WATERS WITH THE GUSTY
WINDS WHICH MAY REACH 30 KT.
OUTLOOK...THURSDAY NIGHT THROUGH SUNDAY...
MODERATE TO HIGH CONFIDENCE IN CONTINUED PERIODS OF 25 KNOT WIND
GUSTS. FIRST IN A COLD AIR ADVECTION PATTERN FROM THE NORTH AND
EAST THROUGH SATURDAY...THEN PERHAPS FROM THE SOUTHWEST BY SUNDAY
BEHIND A WARM FRONT. SMALL CRAFT ADVISORY HEADLINES WILL LIKELY
BE NEEDED THURSDAY NIGHT INTO FRIDAY...ESPECIALLY ACROSS THE
OUTER COASTAL WATERS.
&&
.BOX WATCHES/WARNINGS/ADVISORIES...
CT...NONE.
MA...NONE.
NH...NONE.
RI...NONE.
MARINE...SMALL CRAFT ADVISORY UNTIL 5 PM EST THURSDAY FOR ANZ250-
254>256.
SMALL CRAFT ADVISORY FROM 1 AM TO NOON EST THURSDAY FOR ANZ251.
&&
$$
SYNOPSIS...
NEAR TERM...99
SHORT TERM...
LONG TERM...
AVIATION...
MARINE...
EQUIPMENT...
AREA FORECAST DISCUSSION...UPDATED
NWS TAUNTON MA
744 AM EST WED NOV 28 2012
.SYNOPSIS...
DRIER AND UNSEASONABLY COLD WEATHER ARRIVES LATE TODAY AND LINGERS
THROUGH FRIDAY. A WARM FRONT WILL BRING MUCH MILDER WEATHER FOR
EARLY NEXT WEEK...WITH A CHANCE FOR SOME RAIN LATE SUNDAY INTO
EARLY MONDAY.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
730 AM UPDATE...
MINOR TWEAKS TO BRING TEMPERATURES BACK IN LINE WITH OBSERVED
TRENDS. 28/06Z GFS/NAM AND 28/10Z RAP ALL INDICATE POTENTIAL FOR
OCEAN-EFFECT PRECIPITATION TO DEVELOP IN THE NORTHEAST FLOW ON THE
BACKSIDE OF THE DEPARTING LOW PRESSURE. MADE MINOR TWEAKS TO POPS
TO REFLECT THIS THOUGHT.
PREVIOUS DISCUSSION...
EXPECT LEFTOVER PRECIP ACROSS SE MA...CAPE COD AND THE ISLANDS TO
PUSH OFFSHORE BY 13Z-14Z AS LOW PRES PUSHES OFFSHORE. MOST OF THE
HIGH CLOUDS HAVE MOVED OFFSHORE AS SEEN ON IR SATELLITE. STILL SEE
LOWER CLOUDS ACROSS MOST AREAS AT 09Z. SOME LEFTOVER SHOWERS MAY
LINGER ALONG THE E COAST THROUGH MIDDAY...THOUGH SHOULD SHIFT
OFFSHORE DURING THE AFTERNOON. CLOUDS WILL LIKELY LINGER ACROSS
CENTRAL AND EASTERN AREAS THROUGH A GOOD PORTION OF THE DAY...
WHILE THEY BREAK ACROSS THE WEST AS HIGH PRES RIDGE BEGINS TO
BUILD ACROSS THE REGION. MAY SEE SOME GUSTY NW WINDS ACROSS THE E
COAST THIS MORNING...THEN WILL DIMINISH.
EXPECTING DAYTIME HIGHS MAINLY IN THE MID-UPPER 30S ACROSS S
NH...RANGING TO THE MID 40S ALONG THE S COAST.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH 6 PM THURSDAY/...
TONIGHT...
HIGH PRESSURE WILL BUILD ACROSS THEN TO THE S OF THE REGION DURING
THE NIGHT. PRES GRADIENT WILL INCREASE AS SHOT OF COLDER AIR WILL
WORK IN DURING THE NIGHT...SO WILL SEE SOME WIND GUSTS PICKING UP
MAINLY AFTER MIDNIGHT ALONG THE IMMEDIATE E COAST AS WELL AS THE
CAPE AND ISLANDS. EXPECT OVERNIGHT LOWS MAINLY IN THE 20S...EXCEPT
THE LOWER-MID 30S ACROSS THE MID AND OUTER CAPE AND ISLANDS.
THURSDAY...
HIGH PRES SETTLES ACROSS THE MID ATLC STATES...WINDS WILL DIMINISH
AS THEY BACK TO THE W AND SW DURING THE AFTERNOON. EXPECT DRY
CONDITIONS WITH THE HIGH TO THE S. DAYTIME HIGHS WILL BE IN THE
UPPER 30S TO MID 40S...WHICH WILL STILL BE UP TO 5 DEGREES BELOW
SEASONAL NORMALS.
&&
.LONG TERM /THURSDAY NIGHT THROUGH TUESDAY/...
HIGHLIGHTS...
* DRY AND UNSEASONABLY COLD THURSDAY AND FRIDAY
* A FEW PASSING RAIN/SNOW SHOWERS POSSIBLE SATURDAY...BUT NOT A
WASHOUT
* MUCH MILDER EARLY NEXT WEEK WITH SOME RAIN SHOWERS POSSIBLE LATE
SUNDAY/EARLY MON
28/00Z GUIDANCE CONTINUES TO BE IN VERY GOOD AGREEMENT OVER THIS
PORTION OF THE FORECAST. JUST ABOUT ALL MODELS MAINTAIN A
PROGRESSIVE MID-LEVEL FLOW PATTERN UNTIL THE MIDDLE OF NEXT WEEK.
AS SUCH EXPECTING ONLY WEAK SYNOPTIC SYSTEMS TO IMPACT OUR REGION
AT TIMES...MAINLY FRONTS AS THE PARENT LOW PRESSURES STAY WELL
AWAY FROM OUR REGION.
DETAILS...
THURSDAY NIGHT AND FRIDAY...A FAIRLY STRONG COLD FRONT WILL MOVE
THROUGH THE REGION...BUT IT APPEARS TOO DRY FOR ANY PRECIPITATION.
THIS FRONT WILL RESULT IN THE COLDEST WEATHER SO FAR THIS SEASON.
A STRONG HIGH PRESSURE OVER EASTERN CANADA WILL RESULT IN
NORTHERLY SURFACE WINDS FRIDAY. THIS SHOULD RESULT IN POOR MIXING
AND KEEP THE SHALLOW COLD AIR IN PLACE.
SATURDAY...HIGH PRESSURE OVER QUEBEC WILL SLOWLY MOVE EAST INTO
THE CANADIAN MARITIMES AS A WARM FRONT TRIES TO APPROACH THE
REGION. THIS FRONT MAY BE ENOUGH TO TRIGGER A FEW RAIN/SNOW
SHOWERS...BUT CERTAINLY NOT EXPECTING A WASHOUT OR A SIGNIFICANT
PRECIPITATION EVENT WITH SUCH DRY LOW LEVELS. MAY HAVE TO WATCH
FOR SOME SLICK SPOTS ON THE ROADS IF THERE ENDS UP BEING SOME
LIGHT FROZEN PRECIPITATION...BUT THAT REMAINS UNCERTAIN AT THIS
TIME.
SUNDAY THROUGH TUESDAY...MUCH MILDER MID-LEVEL TEMPERATURES
SHOULD ARRIVE BEHIND A WARM FRONT....RESULTING IN SIGNIFICANTLY
MILDER TEMPERATURES EARLY NEXT WEEK. HIGHS SHOULD TOP OUT WELL
INTO THE 40S IF NOT THE 50S OVER THIS TIME. A FRONT MAY BRING A
ROUND OF RAIN SHOWERS TO THE REGION SOMETIME LATE SUNDAY INTO
EARLY MONDAY...BUT THE REST OF THE TIME LOOKS DRY.
&&
.AVIATION /13Z WEDNESDAY THROUGH SUNDAY/...
FORECASTER CONFIDENCE LEVELS...
LOW...LESS THAN 30 PERCENT
MODERATE...30 PERCENT TO 60 PERCENT
HIGH...GREATER THAN 60 PERCENT
OVERVIEW...MODERATE CONFIDENCE TODAY...HIGH CONFIDENCE TONIGHT
AND THURSDAY.
TODAY...MVFR CIGS MAY LINGER ACROSS CAPE COD AND THE ISLANDS
THROUGH MIDDAY. MAY ALSO SEE AREAS OF IFR CONDITIONS TOWARD EAST
COAST THIS MORNING IN OCEAN-EFFECT SHOWERS. MAY SEE N-NW GUSTS
AROUND 20 KT ALONG E COAST DURING THE AFTERNOON.
TONIGHT AND THURSDAY...
MAINLY VFR CONDITIONS. W-NW WINDS GUSTING TO AROUND 25 KT ACROSS E
COASTAL AREAS LATE TONIGHT AND EARLY THU...THEN BACKING TO W-SW
AND DIMINISHING.
KBOS TAF...HIGH CONFIDENCE IN TRENDS BUT MODERATE CONFIDENCE IN
TIMING.
KBDL TAF...MODERATE TO HIGH CONFIDENCE.
VFR CIGS/MVFR VSBYS EARLY. EXPECT VSBYS TO IMPROVE TO VFR BY
SUNRISE. EXPECT VFR CONDITIONS THROUGH THU WITH FEW-SCT MID AND
HIGH CLOUDS.
OUTLOOK...THURSDAY NIGHT THROUGH SUNDAY...
HIGH CONFIDENCE IN MAINLY VFR CONDITIONS. MAY SEE A PERIOD OF
MVFR CONDITIONS SATURDAY AS A WARM FRONT WORKS TOWARD THE REGION
WITH A FEW RAIN/SNOW SHOWERS. ANOTHER SHOT AT MVFR CONDITIONS WILL
BE LATE SUNDAY/SUNDAY NIGHT WITH A ROUND OF RAIN SHOWERS AHEAD OF
A COLD FRONT.
&&
.MARINE...
MODERATE TO HIGH CONFIDENCE.
TODAY...EXPECT WINDS TO BACK TO N-NW DURING THE DAY AS HIGH PRES
BUILDS OUT OF THE APPALACHIANS. WILL SEE SOME GUSTS UP TO 20-25 KT
ACROSS THE EASTERN WATERS EARLY...THEN WILL DIMINISH. SEAS WILL
REMAIN AOA 5 FT...SO HAVE KEPT SMALL CRAFT GOING.
TONIGHT-THURSDAY...NW WINDS WILL INCREASE AS COLDER AIR WORKS ACROSS
THE WATERS LATE TONIGHT INTO THURSDAY MORNING. EXTENDED THE SMALL
CRAFT THROUGH THURSDAY. WAVE MODELS INDICATING AN INCREASE IN
SEAS...POSSIBLY UP TO 7-8 FT...ON THE OUTER WATERS WITH THE GUSTY
WINDS WHICH MAY REACH 30 KT.
OUTLOOK...THURSDAY NIGHT THROUGH SUNDAY...
MODERATE TO HIGH CONFIDENCE IN CONTINUED PERIODS OF 25 KNOT WIND
GUSTS. FIRST IN A COLD AIR ADVECTION PATTERN FROM THE NORTH AND
EAST THROUGH SATURDAY...THEN PERHAPS FROM THE SOUTHWEST BY SUNDAY
BEHIND A WARM FRONT. SMALL CRAFT ADVISORY HEADLINES WILL LIKELY
BE NEEDED THURSDAY NIGHT INTO FRIDAY...ESPECIALLY ACROSS THE
OUTER COASTAL WATERS.
&&
.BOX WATCHES/WARNINGS/ADVISORIES...
CT...NONE.
MA...NONE.
NH...NONE.
RI...NONE.
MARINE...SMALL CRAFT ADVISORY UNTIL 5 PM EST THURSDAY FOR ANZ250.
SMALL CRAFT ADVISORY FROM 1 AM TO NOON EST THURSDAY FOR ANZ251.
SMALL CRAFT ADVISORY UNTIL 5 PM EST THURSDAY FOR ANZ254>256.
&&
$$
SYNOPSIS...BELK/EVT
NEAR TERM...BELK/EVT
SHORT TERM...EVT
LONG TERM...BELK
AVIATION...BELK/EVT
MARINE...BELK/EVT
AREA FORECAST DISCUSSION...UPDATED
NWS TALLAHASSEE FL
625 AM EST Wed Nov 28 2012
.NEAR TERM [Today and Tonight]...
Updated at: 515 am EST
The Dense Fog Advisory that was previously in effect for portions
of the area has been cancelled. Between 04z and 08z there were a
fair number of observations in SW Georgia that had visibilities
at 1/4SM or 1/2SM, but a recent increase in winds has caused
visibility to improve areawide. Despite a small chance that a couple
of the observations could see visibility dip briefly in patchy fog
early this morning, the probability no longer seems high enough to
warrant an advisory.
A frontal inversion should keep the mixed layer relatively shallow
today, which will keep temperatures cooler than the +10 to +11C
850mb temperatures would suggest. In shallow CAA regimes just
after a cold front passage, the morning temperatures tend to be
slower to increase than the typical diurnal curve. The temperature
curve was nudged down in the morning to account for this. However,
with breaks of sun likely to develop by afternoon we are still
expecting highs to get into the 60s just about everywhere.
For tonight, some MOS guidance is still indicating lows close to
freezing in our SE Alabama zones. However, it would take a very
strong inversion to produce lows of those values given the
temperature profile in the 925-850mb layer. That is not expected
to be the case, and so despite clear skies and lighter winds the
lows should mainly stay in the 37-42 degree range. These types of
lows would also prevent frost in most spots.
&&
.SHORT TERM [Thursday Through Friday]...
A lingering low-level ridge of high pressure along the Atlantic
seaboard will keep east to northeast flow in place across much of
the east coast. This pattern should prevent rapid modification of
the cooler air mass that will be in place. However, highs should
increase a couple degrees each day at the end of the work week
with mostly sunny skies and a deeper mixed layer each afternoon.
&&
.LONG TERM [Friday Night through next Wednesday]...
Guidance is in good agreement that the flow across the CONUS will
continue to be fast and primarily zonal through early next week. The
primary jet and any associated disturbances are forecast to remain
well north of the forecast area through next Tuesday, before digging
southward by midweek and driving a cold front towards the Gulf
Coast. Before this trough digs southward, expect an upper ridge to
develop over the gulf and nose northeast across the area.
The impact of this upper pattern will be for warmer than normal
temperatures into early next week, with minimal rain chances. Expect
highs in the mid 70s with lows generally in the lower 50s. Rain
chances will be introduced for late Tuesday into Wednesday ahead of
the approaching cold front.
&&
.AVIATION [through 12z Thursday]...
Low CIGS & fog currently dominate the region with IFR conditions
ongoing at all terminals. Expect conditions to improve after
sunrise, with the fog burning off before cigs lift. VFR conditions
are anticipated by afternoon and will continue through tonight with
light north to northeast winds.
&&
.MARINE...
With the 4am CWF issuance, we plan to maintain the SCEC headline
across all but the far eastern nearshore zones (Apalachee Bay and
along Taylor and Dixie Counties) through mid-morning. The latest
buoy and tower observations continue to indicate winds around
15-16 knots over the bulk of the coastal waters, with a few gusts
to around 20 knots. A 0315z ASCAT pass also showed a sizable swath
of 15-20 knot winds, which matched well with RAP and local WRF
(which were used as the basis for the updated wind forecast in the
first 12 hours). Winds quickly veer to the east by tonight as high
pressure settles into the Southeast, setting up the typical surges
of easterly winds at night over the next few days.
&&
.FIRE WEATHER...
A slightly drier airmass will filter into the region today in the
wake of a cold front. However, humidity values are not forecast to
reach critical levels, and ERC values should remain below thresholds
following Tuesdays rainfall. By Thursday into the weekend, easterly
flow is forecast to bring in enough Atlantic moisture to keep RH
values above critical levels. No Red Flag conditions are expected
through the end of the work week.
&&
.HYDROLOGY...
Rainfall totals over the past 24 hours ranged from nil or trace
amounts near the Suwannee River in the eastern Florida Big Bend,
to around an inch in southeast Alabama. These rain amounts are not
expected to cause any notable changes in the area rivers.
&&
.PRELIMINARY POINT TEMPS/POPS...
Tallahassee 67 39 70 45 74 / 0 0 0 10 10
Panama City 66 45 68 51 72 / 0 0 0 10 10
Dothan 64 38 67 45 71 / 0 0 0 10 10
Albany 63 37 68 43 72 / 0 0 0 10 10
Valdosta 66 41 70 47 73 / 0 0 0 10 10
Cross City 71 43 74 47 76 / 0 0 0 10 10
Apalachicola 66 47 67 53 71 / 0 0 0 10 10
&&
.TAE WATCHES/WARNINGS/ADVISORIES...
FL...None.
GA...None.
AL...None.
GM...None.
&&
$$
NEAR AND SHORT TERM...Lamers
LONG TERM...Camp
AVIATION...Camp
MARINE...Lamers
FIRE WEATHER...Camp
HYDROLOGY...Lamers
AREA FORECAST DISCUSSION...UPDATED
NWS TALLAHASSEE FL
515 AM EST Wed Nov 28 2012
.NEAR TERM [Today and Tonight]...
Updated at: 515 am EST
The Dense Fog Advisory that was previously in effect for portions
of the area has been cancelled. Between 04z and 08z there were a
fair number of observations in SW Georgia that had visibilities
at 1/4SM or 1/2SM, but a recent increase in winds has caused
visibility to improve areawide. Despite a small chance that a couple
of the observations could see visibility dip briefly in patchy fog
early this morning, the probability no longer seems high enough to
warrant an advisory.
A frontal inversion should keep the mixed layer relatively shallow
today, which will keep temperatures cooler than the +10 to +11C
850mb temperatures would suggest. In shallow CAA regimes just
after a cold front passage, the morning temperatures tend to be
slower to increase than the typical diurnal curve. The temperature
curve was nudged down in the morning to account for this. However,
with breaks of sun likely to develop by afternoon we are still
expecting highs to get into the 60s just about everywhere.
For tonight, some MOS guidance is still indicating lows close to
freezing in our SE Alabama zones. However, it would take a very
strong inversion to produce lows of those values given the
temperature profile in the 925-850mb layer. That is not expected
to be the case, and so despite clear skies and lighter winds the
lows should mainly stay in the 37-42 degree range. These types of
lows would also prevent frost in most spots.
&&
.SHORT TERM [Thursday Through Friday]...
A lingering low-level ridge of high pressure along the Atlantic
seaboard will keep east to northeast flow in place across much of
the east coast. This pattern should prevent rapid modification of
the cooler air mass that will be in place. However, highs should
increase a couple degrees each day at the end of the work week
with mostly sunny skies and a deeper mixed layer each afternoon.
&&
.LONG TERM [Friday Night through next Wednesday]...
Guidance is in good agreement that the flow across the CONUS will
continue to be fast and primarily zonal through early next week. The
primary jet and any associated disturbances are forecast to remain
well north of the forecast area through next Tuesday, before digging
southward by midweek and driving a cold front towards the Gulf
Coast. Before this trough digs southward, expect an upper ridge to
develop over the gulf and nose northeast across the area.
The impact of this upper pattern will be for warmer than normal
temperatures into early next week, with minimal rain chances. Expect
highs in the mid 70s with lows generally in the lower 50s. Rain
chances will be introduced for late Tuesday into Wednesday ahead of
the approaching cold front.
&&
.AVIATION [through 06z Thursday]...
Low CIGS & fog currently dominate the region with IFR conditions
ongoing at all terminals. Expect conditions to occasionally reach
airport minimums until after sunrise. Thereafter, the overcast
should gradually burn off, with VFR conditions anticipated by
afternoon and continuing into Wednesday night.
&&
.MARINE...
With the 4am CWF issuance, we plan to maintain the SCEC headline
across all but the far eastern nearshore zones (Apalachee Bay and
along Taylor and Dixie Counties) through mid-morning. The latest
buoy and tower observations continue to indicate winds around
15-16 knots over the bulk of the coastal waters, with a few gusts
to around 20 knots. A 0315z ASCAT pass also showed a sizable swath
of 15-20 knot winds, which matched well with RAP and local WRF
(which were used as the basis for the updated wind forecast in the
first 12 hours). Winds quickly veer to the east by tonight as high
pressure settles into the Southeast, setting up the typical surges
of easterly winds at night over the next few days.
&&
.FIRE WEATHER...
A slightly drier airmass will filter into the region today in the
wake of a cold front. However, humidity values are not forecast to
reach critical levels, and ERC values should remain below thresholds
following Tuesdays rainfall. By Thursday into the weekend, easterly
flow is forecast to bring in enough Atlantic moisture to keep RH
values above critical levels. No Red Flag conditions are expected
through the end of the work week.
&&
.HYDROLOGY...
Rainfall totals over the past 24 hours ranged from nil or trace
amounts near the Suwannee River in the eastern Florida Big Bend,
to around an inch in southeast Alabama. These rain amounts are not
expected to cause any notable changes in the area rivers.
&&
.PRELIMINARY POINT TEMPS/POPS...
Tallahassee 67 39 70 45 74 / 0 0 0 10 10
Panama City 66 45 68 51 72 / 0 0 0 10 10
Dothan 64 38 67 45 71 / 0 0 0 10 10
Albany 63 37 68 43 72 / 0 0 0 10 10
Valdosta 66 41 70 47 73 / 0 0 0 10 10
Cross City 71 43 74 47 76 / 0 0 0 10 10
Apalachicola 66 47 67 53 71 / 0 0 0 10 10
&&
.TAE WATCHES/WARNINGS/ADVISORIES...
FL...None.
GA...None.
AL...None.
GM...None.
&&
$$
NEAR AND SHORT TERM...Lamers
LONG TERM...Camp
AVIATION...Camp
MARINE...Lamers
FIRE WEATHER...Camp
HYDROLOGY...Lamers
AREA FORECAST DISCUSSION
NWS TALLAHASSEE FL
314 AM EST Wed Nov 28 2012
.NEAR TERM [Today and Tonight]...
The immediate forecast challenge is related to fog. As expected,
the lowest visibilities per observations have been over the east
half of the area (SW GA and FL Big Bend). Although the southern
half of the Dense Fog Advisory area has not yet seen many 1/4SM
visibilities observed, we plan to leave the advisory in tact for
now. The latest ensemble probabilities continue to favor a high
likelihood for visibility at or below 1SM over the advisory area.
A frontal inversion should keep the mixed layer relatively shallow
today, which will keep temperatures cooler than the +10 to +11C
850mb temperatures would suggest. In shallow CAA regimes just
after a cold front passage, the morning temperatures tend to be
slower to increase than the typical diurnal curve. The temperature
curve was nudged down in the morning to account for this. However,
with breaks of sun likely to develop by afternoon we are still
expecting highs to get into the 60s just about everywhere.
For tonight, some MOS guidance is still indicating lows close to
freezing in our SE Alabama zones. However, it would take a very
strong inversion to produce lows of those values given the
temperature profile in the 925-850mb layer. That is not expected
to be the case, and so despite clear skies and lighter winds the
lows should mainly stay in the 37-42 degree range. These types of
lows would also prevent frost in most spots.
&&
.SHORT TERM [Thursday Through Friday]...
A lingering low-level ridge of high pressure along the Atlantic
seaboard will keep east to northeast flow in place across much of
the east coast. This pattern should prevent rapid modification of
the cooler air mass that will be in place. However, highs should
increase a couple degrees each day at the end of the work week
with mostly sunny skies and a deeper mixed layer each afternoon.
&&
.LONG TERM [Friday Night through next Wednesday]...
Guidance is in good agreement that the flow across the CONUS will
continue to be fast and primarily zonal through early next week. The
primary jet and any associated disturbances are forecast to remain
well north of the forecast area through next Tuesday, before digging
southward by midweek and driving a cold front towards the Gulf
Coast. Before this trough digs southward, expect an upper ridge to
develop over the gulf and nose northeast across the area.
The impact of this upper pattern will be for warmer than normal
temperatures into early next week, with minimal rain chances. Expect
highs in the mid 70s with lows generally in the lower 50s. Rain
chances will be introduced for late Tuesday into Wednesday ahead of
the approaching cold front.
&&
.AVIATION [through 06z Thursday]...
Low CIGS & fog currently dominate the region with IFR conditions
ongoing at all terminals. Expect conditions to occasionally reach
airport minimums until after sunrise. Thereafter, the overcast
should gradually burn off, with VFR conditions anticipated by
afternoon and continuing into Wednesday night.
&&
.MARINE...
With the 4am CWF issuance, we plan to maintain the SCEC headline
across all but the far eastern nearshore zones (Apalachee Bay and
along Taylor and Dixie Counties) through mid-morning. The latest
buoy and tower observations continue to indicate winds around
15-16 knots over the bulk of the coastal waters, with a few gusts
to around 20 knots. A 0315z ASCAT pass also showed a sizable swath
of 15-20 knot winds, which matched well with RAP and local WRF
(which were used as the basis for the updated wind forecast in the
first 12 hours). Winds quickly veer to the east by tonight as high
pressure settles into the Southeast, setting up the typical surges
of easterly winds at night over the next few days.
&&
.FIRE WEATHER...
A slightly drier airmass will filter into the region today in the
wake of a cold front. However, humidity values are not forecast to
reach critical levels, and ERC values should remain below thresholds
following Tuesdays rainfall. By Thursday into the weekend, easterly
flow is forecast to bring in enough Atlantic moisture to keep RH
values above critical levels. No Red Flag conditions are expected
through the end of the work week.
&&
.HYDROLOGY...
Rainfall totals over the past 24 hours ranged from nil or trace
amounts near the Suwannee River in the eastern Florida Big Bend,
to around an inch in southeast Alabama. These rain amounts are not
expected to cause any notable changes in the area rivers.
&&
.PRELIMINARY POINT TEMPS/POPS...
Tallahassee 67 39 70 45 74 / 0 0 0 10 10
Panama City 66 45 68 51 72 / 0 0 0 10 10
Dothan 64 38 67 45 71 / 0 0 0 10 10
Albany 63 37 68 43 72 / 0 0 0 10 10
Valdosta 66 41 70 47 73 / 0 0 0 10 10
Cross City 71 43 74 47 76 / 0 0 0 10 10
Apalachicola 66 47 67 53 71 / 0 0 0 10 10
&&
.TAE WATCHES/WARNINGS/ADVISORIES...
FL...DENSE FOG ADVISORY until 8 AM EST this morning for Gadsden-
Inland Franklin-Inland Jefferson-Inland Taylor-Inland
Wakulla-Lafayette-Leon-Liberty-Madison.
GA...DENSE FOG ADVISORY until 6 AM EST early this morning for Baker-
Ben Hill-Berrien-Calhoun-Colquitt-Cook-Decatur-Dougherty-
Early-Irwin-Lee-Miller-Mitchell-Seminole-Tift-Turner-
Worth.
DENSE FOG ADVISORY until 8 AM EST this morning for Brooks-
Grady-Lanier-Lowndes-Thomas.
AL...None.
GM...None.
&&
$$
NEAR AND SHORT TERM...Lamers
LONG TERM...Camp
AVIATION...Camp
MARINE...Lamers
FIRE WEATHER...Camp
HYDROLOGY...Lamers
AREA FORECAST DISCUSSION
NWS JACKSON KY
1248 PM EST WED NOV 28 2012
.UPDATE...
ISSUED AT 1248 PM EST WED NOV 28 2012
MADE A FEW MORE TWEAKS TO THE FORECAST FOR THE REST OF TODAY. CLOUD
COVER ACROSS EASTERN KENTUCKY HAS BEEN DISSIPATING ACROSS THE BOARD
MUCH MORE QUICKLY THAN THE PREVIOUS FORECAST UPDATE INDICATED. IN
FACT...SKIES ACROSS MOST OF THE AREA HAVE ALREADY BECOME MOSTLY
CLEAR. TEMPERATURES ACROSS THE THE AREA HAVE RESPONDED IN KIND AND
HAVE BEEN WARMING MORE QUICKLY...SO TODAYS HIGHS ACROSS EASTERN
KENTUCKY HAVE BEEN INCREASED BY A FEW TO EVEN SEVERAL DEGREES...TO
ACCOUNT FOR THE GREATER SUN EXPOSURE SO FAR TODAY. THE REST OF THE
FORECAST WAS IN GOOD SHAPE.
UPDATE ISSUED AT 1029 AM EST WED NOV 28 2012
MADE SOME MODIFICATIONS TO THE TEMPERATURE AND CLOUD COVER FORECAST
FOR THE REST OF TODAY. THE LATEST SATELLITE IMAGERY CLEARLY SHOWS
THAT CLOUD COVER HAS BEEN DISSIPATING MORE QUICKLY THIS MORNING THAN
THE PREVIOUS FORECAST WAS INDICATING. THAT BEING SAID...SPED UP THE
TIMING OF CLOUD DISSIPATION TODAY BY 3 OR 4 HOURS TO REFLECT THE
LATEST TRENDS. WITH OUR WESTERN AND CENTRAL COUNTIES CLEARING OFF
MORE QUICKLY...ALSO INCREASED TODAYS HIGH TEMPERATURES FOR MOST OF
THE FORECAST AREA...TO ACCOUNT FOR THE GREATER THAN EXPECTED AMOUNT
OF SUNSHINE. TODAYS HIGHS ARE NOW EXPECTED TO INCREASE INTO THE LOWER
40S ACROSS MOST OF THE AREA...WITH ONLY A FEW READINGS IN THE UPPER
30S EXPECTED IN THE HIGHER TERRAIN ALONG THE VIRGINIA BORDER. THE
REST OF THE FORECAST WAS IN GOOD SHAPE.
UPDATE ISSUED AT 629 AM EST WED NOV 28 2012
FINALLY STARTING TO SEE SOME HOLES OPEN UP IN THE SKY COVER. SOME OF
THESE HOLES MAY ONLY BE TEMPORARY AS LOW CLOUDS APPEAR TO BE
REDEVELOPING AGAIN. AT THE LEAST...IT AT LEAST SHOW HOW VULNERABLE
THIS STRATUS IS OUT THERE AND IT SHOULD NOT TAKE MUCH TO ELIMINATE
THIS CLOUD COVER TODAY. THUS...STARTING TO FEEL A BIT MORE CONFIDENT
WE WILL LOSE THE REMAINING CLOUD COVER BY EARLY THIS AFTERNOON. HAVE
ADJUSTED THE SKY COVER TO REFLECT THIS NEW THINKING.
&&
.SHORT TERM...(TODAY THROUGH THURSDAY)
ISSUED AT 233 AM EST WED NOV 28 2012
EASTERN KENTUCKY REMAINS UNDERNEATH THE UPPER LEVEL TROUGH ANCHORED
OVER THE NORTHEASTERN US THIS MORNING. AN EMBEDDED SHORTWAVE IS
PUSHING SOUTHEAST ACROSS THE NORTHERN OHIO RIVER VALLEY
PRESENTLY...BUT ANY IMPACTS FROM THIS SYSTEM WILL REMAIN NORTH OF
KENTUCKY. HOWEVER...LOW CLOUDS CONTINUE TO PLAGUE MOST OF EASTERN
KENTUCKY THIS MORNING WITH LITTLE SIGNS THEY ARE GOING AWAY SOON. IN
FACT...IT LOOKS LIKE WITH WEAK NORTHWEST FLOW...CLOUDS HAVE BEEN
REGENERATING ON THE NORTHWEST FLANK WITH THE UPSLOPE FLOW. OVERALL
FLOW IS EXPECTED TO REMAIN FAIRLY WEAK TODAY...SO NOT SURE HOW
QUICKLY THE LOW CLOUDS WILL ERODE. HOWEVER...ALL MODEL
GUIDANCE...INCLUDING THE RUC WHICH IS THE ONLY MODEL INDICATING CLOUD
COVER PRESENTLY...HAS SKIES CLEAR BY MIDDAY. GOING TO HEDGE BETS A
BIT AND KEEP SKIES PARTLY CLOUDY THIS AFTERNOON...WITH THE SOUTHEAST
NOT CLEARING OUT UNTIL THIS EVENING. MUCH LIKE YESTERDAY...UNDER THE
INFLUENCE OF THE UPPER LEVEL TROUGH...CANNOT SEE TEMPERATURES COMING
ANYWHERE CLOSE TO GUIDANCE TODAY. THIS IS ESPECIALLY TRUE IF THE
CLOUD COVER HANGS ON FOR A GOOD BALANCE OF THE DAY. THUS...GOING TO
KEEP TEMPERATURES GENERALLY AROUND 40 FOR HIGHS TODAY.
THE TEMPERATURE FORECAST FOR TONIGHT HINGES COMPLETELY ON CLOUDS
FINALLY MOVING OUT WITH CLEAR SKIES. IF CLOUDS HANG ON AGAIN...WE
WILL LIKELY BE AT LEAST 10 DEGREES WARMER. HOWEVER...GOING TO
CONTINUE TO GO WITH THE COOLER GUIDANCE READINGS AND ACTUALLY A FEW
DEGREES UNDER GUIDANCE IN THE VALLEYS GIVEN THE EXPECTED GOOD
RADIATIONAL COOLING TONIGHT AS THE RIDGE SETTLES OVER THE AREA. AS
THE MID LEVEL RIDGE PUSHES EAST OF US ON THURSDAY...THE WARM UP WILL
FINALLY START AS HIGHS RECOVER TO THE LOWER TO MIDDLE 50S UNDER SUNNY
SKIES.
.LONG TERM...(THURSDAY NIGHT THROUGH TUESDAY)
ISSUED AT 203 AM EST WED NOV 28 2012
SURFACE HIGH PRESSURE OFF THE CAROLINA COAST AND A WEAK 50H TROF OVER
THE MISS RIVER VALLEY. THIS IS THE PATTERN THAT STARTS THE EXTENDED
FORECAST. SOUTHERLY FLOW AT THE SFC WILL BRING WARM AIR FROM THE GULF
WITH A MILD RIDGE/VALLEY SPLIT TO LOW TEMPS FRI MORNING...GENERALLY
FROM THE UPPER 20S TO MID 30S. THEN WARMING CONTINUES ON FRI WITH
FAIR WEATHER AND TEMPS CLIMBING TO NEAR 60. THE WEAK 50H TROF WILL
SWEEP PAST FRI NIGHT...BUT THE BEST ENERGY AND ALL THE PCPN SHOULD
STAY NORTH OF THE OHIO RIVER. THE FAIR WEATHER WILL CONTINUE UNTIL
LATE SUNDAY AFTERNOON WHEN THE UPPER AIR PATTERN BEGINS TO SHOW SOME
TROUGHING OVER THE OHIO VALLEY WITH A RIDGE BUILDING IN THE PLAINS.
THIS UPPER AIR PATTERN WILL BRING A DISTURBANCE THRU THE REGION WITH
A SMALL CHANCE FOR RAIN TO ERN KY. BY MONDAY A MAJOR TROF EMERGES
FROM THE ROCKY MTNS INTO THE WRN PLAINS. A LOW DEVELOPS ALONG THE
CONUS/CANADIAN BORDER IN NORTH DAKOTA AND WILL TRACK INTO THE GREAT
LAKES BY TUE. A TRAILING COLD FRONT WILL BRING A BETTER CHANCE FOR
RAIN TO THE AREA BY TUE AFTERNOON WITH A CHANGE IN THE WARMING TREND.
UNTIL THEN EXPECT HIGHS CLIMBING SLIGHTLY EACH DAY WITH READINGS IN
THE LOWER 60S ON SAT...AND THE MID 60S JUST BEFORE THE RAIN MOVES IN
ON TUE.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z THURSDAY AFTERNOON)
ISSUED AT 1248 PM EST WED NOV 28 2012
CLOUD COVER HAS BEEN DISSIPATING RATHER QUICKLY ACROSS EASTERN
KENTUCKY TODAY...AND THIS TREND IS EXPECTED TO CONTINUE FOR THE REST
OF THE DAY. THE TAF SITES WILL SEE VFR CONDITIONS THROUGH THE END OF
THE TAF PERIOD. CLEAR SKIES AND LIGHT WINDS WILL BE ON TAP AT ALL
THREE AIRPORTS THROUGH TOMORROW AFTERNOON.
&&
.JKL WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...AR
SHORT TERM...KAS
LONG TERM....DUSTY
AVIATION...AR
AREA FORECAST DISCUSSION
NWS JACKSON KY
1029 AM EST WED NOV 28 2012
.UPDATE...
ISSUED AT 1029 AM EST WED NOV 28 2012
MADE SOME MODIFICATIONS TO THE TEMPERATURE AND CLOUD COVER FORECAST
FOR THE REST OF TODAY. THE LATEST SATELLITE IMAGERY CLEARLY SHOWS
THAT CLOUD COVER HAS BEEN DISSIPATING MORE QUICKLY THIS MORNING THAN
THE PREVIOUS FORECAST WAS INDICATING. THAT BEING SAID...SPED UP THE
TIMING OF CLOUD DISSIPATION TODAY BY 3 OR 4 HOURS TO REFLECT THE
LATEST TRENDS. WITH OUR WESTERN AND CENTRAL COUNTIES CLEARING OFF
MORE QUICKLY...ALSO INCREASED TODAYS HIGH TEMPERATURES FOR MOST OF
THE FORECAST AREA...TO ACCOUNT FOR THE GREATER THAN EXPECTED AMOUNT
OF SUNSHINE. TODAYS HIGHS ARE NOW EXPECTED TO INCREASE INTO THE LOWER
40S ACROSS MOST OF THE AREA...WITH ONLY A FEW READINGS IN THE UPPER
30S EXPECTED IN THE HIGHER TERRAIN ALONG THE VIRGINIA BORDER. THE
REST OF THE FORECAST WAS IN GOOD SHAPE.
UPDATE ISSUED AT 629 AM EST WED NOV 28 2012
FINALLY STARTING TO SEE SOME HOLES OPEN UP IN THE SKY COVER. SOME OF
THESE HOLES MAY ONLY BE TEMPORARY AS LOW CLOUDS APPEAR TO BE
REDEVELOPING AGAIN. AT THE LEAST...IT AT LEAST SHOW HOW VULNERABLE
THIS STRATUS IS OUT THERE AND IT SHOULD NOT TAKE MUCH TO ELIMINATE
THIS CLOUD COVER TODAY. THUS...STARTING TO FEEL A BIT MORE CONFIDENT
WE WILL LOSE THE REMAINING CLOUD COVER BY EARLY THIS AFTERNOON. HAVE
ADJUSTED THE SKY COVER TO REFLECT THIS NEW THINKING.
&&
.SHORT TERM...(TODAY THROUGH THURSDAY)
ISSUED AT 233 AM EST WED NOV 28 2012
EASTERN KENTUCKY REMAINS UNDERNEATH THE UPPER LEVEL TROUGH ANCHORED
OVER THE NORTHEASTERN US THIS MORNING. AN EMBEDDED SHORTWAVE IS
PUSHING SOUTHEAST ACROSS THE NORTHERN OHIO RIVER VALLEY
PRESENTLY...BUT ANY IMPACTS FROM THIS SYSTEM WILL REMAIN NORTH OF
KENTUCKY. HOWEVER...LOW CLOUDS CONTINUE TO PLAGUE MOST OF EASTERN
KENTUCKY THIS MORNING WITH LITTLE SIGNS THEY ARE GOING AWAY SOON. IN
FACT...IT LOOKS LIKE WITH WEAK NORTHWEST FLOW...CLOUDS HAVE BEEN
REGENERATING ON THE NORTHWEST FLANK WITH THE UPSLOPE FLOW. OVERALL
FLOW IS EXPECTED TO REMAIN FAIRLY WEAK TODAY...SO NOT SURE HOW
QUICKLY THE LOW CLOUDS WILL ERODE. HOWEVER...ALL MODEL
GUIDANCE...INCLUDING THE RUC WHICH IS THE ONLY MODEL INDICATING CLOUD
COVER PRESENTLY...HAS SKIES CLEAR BY MIDDAY. GOING TO HEDGE BETS A
BIT AND KEEP SKIES PARTLY CLOUDY THIS AFTERNOON...WITH THE SOUTHEAST
NOT CLEARING OUT UNTIL THIS EVENING. MUCH LIKE YESTERDAY...UNDER THE
INFLUENCE OF THE UPPER LEVEL TROUGH...CANNOT SEE TEMPERATURES COMING
ANYWHERE CLOSE TO GUIDANCE TODAY. THIS IS ESPECIALLY TRUE IF THE
CLOUD COVER HANGS ON FOR A GOOD BALANCE OF THE DAY. THUS...GOING TO
KEEP TEMPERATURES GENERALLY AROUND 40 FOR HIGHS TODAY.
THE TEMPERATURE FORECAST FOR TONIGHT HINGES COMPLETELY ON CLOUDS
FINALLY MOVING OUT WITH CLEAR SKIES. IF CLOUDS HANG ON AGAIN...WE
WILL LIKELY BE AT LEAST 10 DEGREES WARMER. HOWEVER...GOING TO
CONTINUE TO GO WITH THE COOLER GUIDANCE READINGS AND ACTUALLY A FEW
DEGREES UNDER GUIDANCE IN THE VALLEYS GIVEN THE EXPECTED GOOD
RADIATIONAL COOLING TONIGHT AS THE RIDGE SETTLES OVER THE AREA. AS
THE MID LEVEL RIDGE PUSHES EAST OF US ON THURSDAY...THE WARM UP WILL
FINALLY START AS HIGHS RECOVER TO THE LOWER TO MIDDLE 50S UNDER SUNNY
SKIES.
.LONG TERM...(THURSDAY NIGHT THROUGH TUESDAY)
ISSUED AT 203 AM EST WED NOV 28 2012
SURFACE HIGH PRESSURE OFF THE CAROLINA COAST AND A WEAK 50H TROF OVER
THE MISS RIVER VALLEY. THIS IS THE PATTERN THAT STARTS THE EXTENDED
FORECAST. SOUTHERLY FLOW AT THE SFC WILL BRING WARM AIR FROM THE GULF
WITH A MILD RIDGE/VALLEY SPLIT TO LOW TEMPS FRI MORNING...GENERALLY
FROM THE UPPER 20S TO MID 30S. THEN WARMING CONTINUES ON FRI WITH
FAIR WEATHER AND TEMPS CLIMBING TO NEAR 60. THE WEAK 50H TROF WILL
SWEEP PAST FRI NIGHT...BUT THE BEST ENERGY AND ALL THE PCPN SHOULD
STAY NORTH OF THE OHIO RIVER. THE FAIR WEATHER WILL CONTINUE UNTIL
LATE SUNDAY AFTERNOON WHEN THE UPPER AIR PATTERN BEGINS TO SHOW SOME
TROUGHING OVER THE OHIO VALLEY WITH A RIDGE BUILDING IN THE PLAINS.
THIS UPPER AIR PATTERN WILL BRING A DISTURBANCE THRU THE REGION WITH
A SMALL CHANCE FOR RAIN TO ERN KY. BY MONDAY A MAJOR TROF EMERGES
FROM THE ROCKY MTNS INTO THE WRN PLAINS. A LOW DEVELOPS ALONG THE
CONUS/CANADIAN BORDER IN NORTH DAKOTA AND WILL TRACK INTO THE GREAT
LAKES BY TUE. A TRAILING COLD FRONT WILL BRING A BETTER CHANCE FOR
RAIN TO THE AREA BY TUE AFTERNOON WITH A CHANGE IN THE WARMING TREND.
UNTIL THEN EXPECT HIGHS CLIMBING SLIGHTLY EACH DAY WITH READINGS IN
THE LOWER 60S ON SAT...AND THE MID 60S JUST BEFORE THE RAIN MOVES IN
ON TUE.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z THURSDAY MORNING)
ISSUED AT 629 AM EST WED NOV 28 2012
LOW CLOUDS ARE STARTING TO SHOW MORE HOLES EARLY THIS MORNING AND I
WOULD EXPECT THE STRATUS TO ERODE DURING THE REMAINDER OF THE MORNING
HOURS...GIVING WAY TO VFR CONDITIONS FOR THE AFTERNOON AND TONIGHT.
VFR CONDITIONS SHOULD THEN CONTINUE FOR THE BALANCE OF THE WEEK.
&&
.JKL WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...AR
SHORT TERM...KAS
LONG TERM....DUSTY
AVIATION...KAS
AREA FORECAST DISCUSSION
NWS JACKSON KY
629 AM EST WED NOV 28 2012
.UPDATE...
ISSUED AT 629 AM EST WED NOV 28 2012
FINALLY STARTING TO SEE SOME HOLES OPEN UP IN THE SKY COVER. SOME OF
THESE HOLES MAY ONLY BE TEMPORARY AS LOW CLOUDS APPEAR TO BE
REDEVELOPING AGAIN. AT THE LEAST...IT AT LEAST SHOW HOW VULNERABLE
THIS STRATUS IS OUT THERE AND IT SHOULD NOT TAKE MUCH TO ELIMINATE
THIS CLOUD COVER TODAY. THUS...STARTING TO FEEL A BIT MORE CONFIDENT
WE WILL LOSE THE REMAINING CLOUD COVER BY EARLY THIS AFTERNOON. HAVE
ADJUSTED THE SKY COVER TO REFLECT THIS NEW THINKING.
&&
.SHORT TERM...(TODAY THROUGH THURSDAY)
ISSUED AT 233 AM EST WED NOV 28 2012
EASTERN KENTUCKY REMAINS UNDERNEATH THE UPPER LEVEL TROUGH ANCHORED
OVER THE NORTHEASTERN US THIS MORNING. AN EMBEDDED SHORTWAVE IS
PUSHING SOUTHEAST ACROSS THE NORTHERN OHIO RIVER VALLEY
PRESENTLY...BUT ANY IMPACTS FROM THIS SYSTEM WILL REMAIN NORTH OF
KENTUCKY. HOWEVER...LOW CLOUDS CONTINUE TO PLAGUE MOST OF EASTERN
KENTUCKY THIS MORNING WITH LITTLE SIGNS THEY ARE GOING AWAY SOON. IN
FACT...IT LOOKS LIKE WITH WEAK NORTHWEST FLOW...CLOUDS HAVE BEEN
REGENERATING ON THE NORTHWEST FLANK WITH THE UPSLOPE FLOW. OVERALL
FLOW IS EXPECTED TO REMAIN FAIRLY WEAK TODAY...SO NOT SURE HOW
QUICKLY THE LOW CLOUDS WILL ERODE. HOWEVER...ALL MODEL
GUIDANCE...INCLUDING THE RUC WHICH IS THE ONLY MODEL INDICATING CLOUD
COVER PRESENTLY...HAS SKIES CLEAR BY MIDDAY. GOING TO HEDGE BETS A
BIT AND KEEP SKIES PARTLY CLOUDY THIS AFTERNOON...WITH THE SOUTHEAST
NOT CLEARING OUT UNTIL THIS EVENING. MUCH LIKE YESTERDAY...UNDER THE
INFLUENCE OF THE UPPER LEVEL TROUGH...CANNOT SEE TEMPERATURES COMING
ANYWHERE CLOSE TO GUIDANCE TODAY. THIS IS ESPECIALLY TRUE IF THE
CLOUD COVER HANGS ON FOR A GOOD BALANCE OF THE DAY. THUS...GOING TO
KEEP TEMPERATURES GENERALLY AROUND 40 FOR HIGHS TODAY.
THE TEMPERATURE FORECAST FOR TONIGHT HINGES COMPLETELY ON CLOUDS
FINALLY MOVING OUT WITH CLEAR SKIES. IF CLOUDS HANG ON AGAIN...WE
WILL LIKELY BE AT LEAST 10 DEGREES WARMER. HOWEVER...GOING TO
CONTINUE TO GO WITH THE COOLER GUIDANCE READINGS AND ACTUALLY A FEW
DEGREES UNDER GUIDANCE IN THE VALLEYS GIVEN THE EXPECTED GOOD
RADIATIONAL COOLING TONIGHT AS THE RIDGE SETTLES OVER THE AREA. AS
THE MID LEVEL RIDGE PUSHES EAST OF US ON THURSDAY...THE WARM UP WILL
FINALLY START AS HIGHS RECOVER TO THE LOWER TO MIDDLE 50S UNDER SUNNY
SKIES.
.LONG TERM...(THURSDAY NIGHT THROUGH TUESDAY)
ISSUED AT 203 AM EST WED NOV 28 2012
SURFACE HIGH PRESSURE OFF THE CAROLINA COAST AND A WEAK 50H TROF OVER
THE MISS RIVER VALLEY. THIS IS THE PATTERN THAT STARTS THE EXTENDED
FORECAST. SOUTHERLY FLOW AT THE SFC WILL BRING WARM AIR FROM THE GULF
WITH A MILD RIDGE/VALLEY SPLIT TO LOW TEMPS FRI MORNING...GENERALLY
FROM THE UPPER 20S TO MID 30S. THEN WARMING CONTINUES ON FRI WITH
FAIR WEATHER AND TEMPS CLIMBING TO NEAR 60. THE WEAK 50H TROF WILL
SWEEP PAST FRI NIGHT...BUT THE BEST ENERGY AND ALL THE PCPN SHOULD
STAY NORTH OF THE OHIO RIVER. THE FAIR WEATHER WILL CONTINUE UNTIL
LATE SUNDAY AFTERNOON WHEN THE UPPER AIR PATTERN BEGINS TO SHOW SOME
TROUGHING OVER THE OHIO VALLEY WITH A RIDGE BUILDING IN THE PLAINS.
THIS UPPER AIR PATTERN WILL BRING A DISTURBANCE THRU THE REGION WITH
A SMALL CHANCE FOR RAIN TO ERN KY. BY MONDAY A MAJOR TROF EMERGES
FROM THE ROCKY MTNS INTO THE WRN PLAINS. A LOW DEVELOPS ALONG THE
CONUS/CANADIAN BORDER IN NORTH DAKOTA AND WILL TRACK INTO THE GREAT
LAKES BY TUE. A TRAILING COLD FRONT WILL BRING A BETTER CHANCE FOR
RAIN TO THE AREA BY TUE AFTERNOON WITH A CHANGE IN THE WARMING TREND.
UNTIL THEN EXPECT HIGHS CLIMBING SLIGHTLY EACH DAY WITH READINGS IN
THE LOWER 60S ON SAT...AND THE MID 60S JUST BEFORE THE RAIN MOVES IN
ON TUE.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z THURSDAY MORNING)
ISSUED AT 629 AM EST WED NOV 28 2012
LOW CLOUDS ARE STARTING TO SHOW MORE HOLES EARLY THIS MORNING AND I
WOULD EXPECT THE STRATUS TO ERODE DURING THE REMAINDER OF THE MORNING
HOURS...GIVING WAY TO VFR CONDITIONS FOR THE AFTERNOON AND TONIGHT.
VFR CONDITIONS SHOULD THEN CONTINUE FOR THE BALANCE OF THE WEEK.
&&
.JKL WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...KAS
SHORT TERM...KAS
LONG TERM....DUSTY
AVIATION...KAS
AREA FORECAST DISCUSSION
NWS JACKSON KY
233 AM EST WED NOV 28 2012
.SHORT TERM...(TODAY THROUGH THURSDAY)
ISSUED AT 233 AM EST WED NOV 28 2012
EASTERN KENTUCKY REMAINS UNDERNEATH THE UPPER LEVEL TROUGH ANCHORED
OVER THE NORTHEASTERN US THIS MORNING. AN EMBEDDED SHORTWAVE IS
PUSHING SOUTHEAST ACROSS THE NORTHERN OHIO RIVER VALLEY
PRESENTLY...BUT ANY IMPACTS FROM THIS SYSTEM WILL REMAIN NORTH OF
KENTUCKY. HOWEVER...LOW CLOUDS CONTINUE TO PLAGUE MOST OF EASTERN
KENTUCKY THIS MORNING WITH LITTLE SIGNS THEY ARE GOING AWAY SOON. IN
FACT...IT LOOKS LIKE WITH WEAK NORTHWEST FLOW...CLOUDS HAVE BEEN
REGENERATING ON THE NORTHWEST FLANK WITH THE UPSLOPE FLOW. OVERALL
FLOW IS EXPECTED TO REMAIN FAIRLY WEAK TODAY...SO NOT SURE HOW
QUICKLY THE LOW CLOUDS WILL ERODE. HOWEVER...ALL MODEL
GUIDANCE...INCLUDING THE RUC WHICH IS THE ONLY MODEL INDICATING CLOUD
COVER PRESENTLY...HAS SKIES CLEAR BY MIDDAY. GOING TO HEDGE BETS A
BIT AND KEEP SKIES PARTLY CLOUDY THIS AFTERNOON...WITH THE SOUTHEAST
NOT CLEARING OUT UNTIL THIS EVENING. MUCH LIKE YESTERDAY...UNDER THE
INFLUENCE OF THE UPPER LEVEL TROUGH...CANNOT SEE TEMPERATURES COMING
ANYWHERE CLOSE TO GUIDANCE TODAY. THIS IS ESPECIALLY TRUE IF THE
CLOUD COVER HANGS ON FOR A GOOD BALANCE OF THE DAY. THUS...GOING TO
KEEP TEMPERATURES GENERALLY AROUND 40 FOR HIGHS TODAY.
THE TEMPERATURE FORECAST FOR TONIGHT HINGES COMPLETELY ON CLOUDS
FINALLY MOVING OUT WITH CLEAR SKIES. IF CLOUDS HANG ON AGAIN...WE
WILL LIKELY BE AT LEAST 10 DEGREES WARMER. HOWEVER...GOING TO
CONTINUE TO GO WITH THE COOLER GUIDANCE READINGS AND ACTUALLY A FEW
DEGREES UNDER GUIDANCE IN THE VALLEYS GIVEN THE EXPECTED GOOD
RADIATIONAL COOLING TONIGHT AS THE RIDGE SETTLES OVER THE AREA. AS
THE MID LEVEL RIDGE PUSHES EAST OF US ON THURSDAY...THE WARM UP WILL
FINALLY START AS HIGHS RECOVER TO THE LOWER TO MIDDLE 50S UNDER SUNNY
SKIES.
.LONG TERM...(THURSDAY NIGHT THROUGH TUESDAY)
ISSUED AT 203 AM EST WED NOV 28 2012
SURFACE HIGH PRESSURE OFF THE CAROLINA COAST AND A WEAK 50H TROF OVER
THE MISS RIVER VALLEY. THIS IS THE PATTERN THAT STARTS THE EXTENDED
FORECAST. SOUTHERLY FLOW AT THE SFC WILL BRING WARM AIR FROM THE GULF
WITH A MILD RIDGE/VALLEY SPLIT TO LOW TEMPS FRI MORNING...GENERALLY
FROM THE UPPER 20S TO MID 30S. THEN WARMING CONTINUES ON FRI WITH
FAIR WEATHER AND TEMPS CLIMBING TO NEAR 60. THE WEAK 50H TROF WILL
SWEEP PAST FRI NIGHT...BUT THE BEST ENERGY AND ALL THE PCPN SHOULD
STAY NORTH OF THE OHIO RIVER. THE FAIR WEATHER WILL CONTINUE UNTIL
LATE SUNDAY AFTERNOON WHEN THE UPPER AIR PATTERN BEGINS TO SHOW SOME
TROUGHING OVER THE OHIO VALLEY WITH A RIDGE BUILDING IN THE PLAINS.
THIS UPPER AIR PATTERN WILL BRING A DISTURBANCE THRU THE REGION WITH
A SMALL CHANCE FOR RAIN TO ERN KY. BY MONDAY A MAJOR TROF EMERGES
FROM THE ROCKY MTNS INTO THE WRN PLAINS. A LOW DEVELOPS ALONG THE
CONUS/CANADIAN BORDER IN NORTH DAKOTA AND WILL TRACK INTO THE GREAT
LAKES BY TUE. A TRAILING COLD FRONT WILL BRING A BETTER CHANCE FOR
RAIN TO THE AREA BY TUE AFTERNOON WITH A CHANGE IN THE WARMING TREND.
UNTIL THEN EXPECT HIGHS CLIMBING SLIGHTLY EACH DAY WITH READINGS IN
THE LOWER 60S ON SAT...AND THE MID 60S JUST BEFORE THE RAIN MOVES IN
ON TUE.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z WEDNESDAY NIGHT)
ISSUED AT 1230 AM EST WED NOV 28 2012
LOW CLOUDS HAVE SHOWN LITTLE SIGNS OF ERODING OVERNIGHT AND WILL
LIKELY PERSIST THROUGH AT LEAST DAYBREAK FOR THE TAF SITES. THIS
CLOUD COVER HAS ALREADY PROVED TO BE STUBBORN AND DESPITE THE LACK OF
MODEL SUPPORT...THE CLOUD COVER COULD PERSIST THROUGH THE MORNING
BEFORE FINALLY STARTING TO ERODE LATER THIS AFTERNOON. HOWEVER...WITH
NORTHWEST FLOW IN PLACE AND NO REAL SURGE OF DRIER AIR...WE MAY
CONTEND WITH THE CLOUD COVER FOR A GOOD CHUNK OF THE DAY. NOT GOING
TO CARRY CLOUDS THIS LONG THOUGH AS CONFIDENCE REMAINS VERY LOW.
REGARDLESS...GOING TO PLAN FOR MORE LOW CLOUDS UNTIL WE SEE SOME
EVIDENCE THEY ARE GOING TO GO AWAY WHICH MAY NOT BE UNTIL THIS
TONIGHT WITH THE RIDGE AXIS FINALLY PUSHES TOWARDS THE AREA FROM THE
WEST.
&&
.JKL WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...KAS
LONG TERM....DUSTY
AVIATION...KAS
AREA FORECAST DISCUSSION
NWS LAKE CHARLES LA
1147 AM CST WED NOV 28 2012
.AVIATION...AFTER A DELAY THE LOW STRATUS DECK HAS BURNED OFF
UNDER THE LOW ANGLE LATE NOVEMBER SUN. MORNING SOUNDING REVEALED A
SHALLOW MOIST LAYER TOPPING AT 700 FEET. A BURNOFF TEMP OF 46
DEGREES VALIDATED AT LCH AND LFT. ARA WAS ANOTHER MATTER WITH THAT
TEMP EXCEEDED YET IT TOOK EXTRAPOLATION OF THE CLEARING LINE
TO TAKE THE HONORS AT 17Z. FIFTEEN MINUTES LATER THE LOW CLOUDS
DID INDEED ERODE TO THE COAST. NOT EXPECTING A REPEAT TONIGHT AS
THE RUC SHOWS CONTINUED NORTHEAST FLOW AND DRY AIR AS THE HIGH
PRESSURE RIDGE DOMINATES ALTHOUGH HOW MUCH OF THE MOISTURE REMAINS
IN THAT SHALLOW LAYER BELOW THE 925HPA LEVEL IS AN OPEN QUESTION.
SWEENEY
&&
.PREV DISCUSSION... /ISSUED 1023 AM CST WED NOV 28 2012/
DISCUSSION...
AFTER MONITORING OBSERVATIONS OVER THE PAST HOUR AND REVIEWING
ADDITIONAL MODEL DATA...IT APPEARS THE MARINE FOG IS LIKELY TO
PERSIST LONGER THAT PREVIOUSLY INDICATED. OPTED TO ISSUE A MARINE
DENSE FOG ADVISORY THROUGH MID AFTERNOON FOR THE COASTAL WATERS
WITHIN 20 NM FROM CAMERON TO THE LOWER ATCHAFALAYA RIVER. THE
OBSERVATION SITES REPORTING THE RESTRICTIONS ARE A BIT ELEVATED...SO
THE VISIBILITY AT THE WATER SURFACE MAY NOT BE AS BAD AS THE OBS
PORTRAY...BUT WOULD PREFER TO ERR ON THE SIDE OF CAUTION.
THE INLAND FOG WORDING WAS ALSO TEMPERED DOWN TO PATCHY.
13
PREV DISCUSSION... /ISSUED 911 AM CST WED NOV 28 2012/
DISCUSSION...
EARLY MORNING UPDATE ISSUED TO ADDRESS LOW STRATUS AND FOG OVER
CENTRAL AND SOUTHERN LOUISIANA AND THE ADJACENT GULF WATERS.
DETERMINISTIC MODEL DATA INDICATES THE INLAND STRATUS/FOG WILL
ERODE PRIOR TO NOON AS THE AIRMASS UNDERNEATH THE FRONTAL
INVERSION WARMS. LATEST OBS INDICATE VISIBILITY IS ALREADY
STARTING TO IMPROVE HERE OVER THE COASTAL PARISHES. THE MARINE
STRATUS IS LIKELY TO REMAIN UNTIL THE AFTERNOON...THOUGH I HAVE
SHOWN THE VISIBILITY IMPROVING BEFORE THEN. WILL CONTINUE TO
MONITOR OBS OVER THE NEXT COUPLE OF HOURS AND UPDATE AGAIN AS
WARRANTED.
13
PREV DISCUSSION... /ISSUED 631 AM CST WED NOV 28 2012/
AVIATION...
LOW CLOUDS AND FOG CONTINUE TO SPILL IN FROM THE NORTHEAST BEHIND
THE FRONT. HAVE PUT CLOUDS IN ALL LA TAF SITES WHILE BPT SHOULD BE
THE LEAST AFFECTED OF THE TAF LOCATIONS. VFR WEATHER EXPECTED AT
ALL SITES BEFORE THE NOON HOUR.
PREV DISCUSSION... /ISSUED 337 AM CST WED NOV 28 2012/
DISCUSSION...
COOL SFC HIGH CONTINUES TO BUILD S ACROSS SE TX/LA THIS MORNING.
CLOUDS WERE INITIALLY CLEARING FROM N TO S LAST EVENING. HOWEVER...
VERY LOW CEILINGS AND LOWER VSBY CONTINUE TO BUILD W ACROSS C AND
SC LA THIS MORNING. SINCE THIS IS A VERY THIN LOW LEVEL LAYER OF
MOISTURE NEAR THE SFC...THESE LOWER CEILINGS ARE EXPECTED TO MIX
OUT LATER THIS MORNING AFTER SUNRISE. EXPECTING A RATHER PLEASANT
LATE FALL AFTERNOON WITH TEMPS IN THE LOWER TO MID 60S.
THE SFC HIGH TO OUR NORTH WILL SLIP EAST TONIGHT...BUT ENOUGH
RIDGING WILL HOLD TO PROVIDE ONE MORE COLD NIGHT...ESPECIALLY OVER
C LA WHERE L&V WINDS WILL PREVAIL OVERNIGHT. CONTINUED ONGOING
FORECAST OF LOWER 30S ACROSS THIS REGION...WITH THE POSSIBILITY OF
A FEW LOCATIONS REACHING THE FREEZING MARK FOR AN HOUR NEAR
SUNRISE. HIGHS THU SHOULD REACH THE MID/UPPER 60S.
A WEAK UPPER LEVEL DISTURBANCE WILL INCREASE CLOUDS FROM THE W
LATE THU INTO FRI...ALONG WITH A SLIGHT CHANCE OF SHRA ON FRI. NO
FRONT ASSOCIATED WITH THIS SYSTEM...AS A SLOW MODERATION IN TEMPS
WILL CONTINUE WITH POPS LESS THAN 20% EXPECTED.
LOOKING INTO THE EXTENDED...THE NEXT COLD FRONT IS STILL EXPECTED
TO MOVE THRU TUE/EARLY WED. THE ECMWF LOOKS A LITTLE BIT MOIST ON
THIS LATEST RUN...A LITTLE MORE SO THAN THE GFS. BUMPED UP POPS
FROM 20% TO 30% FOR THIS PERIOD...AND MAY HAVE TO BE RAISED SOME
MORE IF THE ECMWF TRENDS CONTINUE.
DML
MARINE...
NE WINDS TODAY WILL BECOME MORE E ON THU AS SURFACE HIGH PRESSURE
ADVANCES EAST OF THE AREA. AN UPPER LEVEL DISTURBANCE EXPECTED TO
MOVE ACROSS THE NORTHWEST GULF ON FRI COULD PRODUCE A FEW SHOWERS
AND THUNDERSTORMS BEFORE EXITING EAST.
DML
&&
.PRELIMINARY POINT TEMPS/POPS...
KLCH 64 40 67 51 71 / 0 0 10 10 20
KBPT 64 42 67 55 71 / 0 0 10 20 20
KAEX 62 33 67 44 70 / 0 0 10 10 20
KLFT 63 39 67 50 71 / 0 0 10 10 20
&&
.LCH WATCHES/WARNINGS/ADVISORIES...
LA...NONE.
TX...NONE.
GM...DENSE FOG ADVISORY UNTIL 3 PM CST THIS AFTERNOON FOR THE
FOLLOWING ZONES: COASTAL WATERS FROM INTRACOASTAL CITY TO
CAMERON LA OUT 20 NM...COASTAL WATERS FROM LOWER
ATCHAFALAYA RIVER TO INTRACOASTAL CITY LA OUT 20 NM...
VERMILION BAY.
&&
$$
AREA FORECAST DISCUSSION
NWS PITTSBURGH PA
1231 PM EST WED NOV 28 2012
.SYNOPSIS...
A CLIPPER SYSTEM CROSSING THE GREAT LAKES COULD SPAWN A FEW
FLURRIES NORTH OF I-80 THIS AFTERNOON. OTHERWISE...HIGH PRESSURE
BUILDING NORTHWARD WILL PROMOTE DRY WEATHER INTO FRIDAY. TEMPERATURES
WILL BE SLIGHTLY COLDER THAN NORMAL TONIGHT AND WEDNESDAY...BUT
THEN MODERATE THURSDAY AND FRIDAY.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
AN UPPER LEVEL SHORTWAVE/CLIPPER SYSTEM WILL CONTINUE TO CROSS THE
GREAT LAKES THIS AFTERNOON. WITH THE REINFORCEMENT OF COLD
AIR EXPECT CLOUD COVER TO CONTINUE...ESPECIALLY OVER THE NORTHERN
ZONES...FOR THE REMAINDER OF THE DAY. IN ADDITION...LAKE EFFECT
SNOW SHOWERS WILL BE POSSIBLE DOWNWIND OF LAKE ERIE THIS
AFTERNOON. A CONVERGENCE ZONE ALONG LAKE ERIE IS ALREADY SUGGESTED IN
BOTH THE METARS AND CONVECTIVE CLOUD COVER OVER THE LAKE.
HOWEVER...LOW LEVEL FLOW REMAINS SOUTHWESTERLY...KEEPING THE
BETTER CHANCE FOR SNOW NORTH OF OUR ZONES UNTIL LATE THIS EVENING
WHEN THE FLOW SHIFTS TO A MORE WEST/NORTHWEST COMPONENT. WITH
THIS...WILL ONLY KEEP MOSTLY CLOUDY MENTION IN THE GRIDS FOR THE
NORTHERN AND RIDGELINE COUNTIES THROUGH THE EVENING AND LEAVE ONLY
A SLIGHT CHANCE OF FLURRIES IN THE EXTREME NORTHERN PORTION OF OUR
CWA.
ELSEWHERE...UPDATED CLOUD COVER TO DECREASE AMOUNTS THROUGH THE
EVENING HOURS. WITH PLENTY OF VERTICAL MIXING AND
SUNSHINE...TEMPERATURES COULD REACH A DEGREE OR TWO WARMER THAN
PREVIOUSLY FORECAST.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH FRIDAY/...
H8 FLOW WILL SHIFT TO THE NORTHWEST THIS EVENING AND REMAIN THERE
FOR MOST OF THE NIGHT. BASED OFF OF THE MOST RECENT MODEL
SOUNDINGS...THIS SHOULD KEEP SOME CLOUD COVER OVER AT LEAST POINTS
NORTH OF PITTSBURGH FOR THE REMAINDER OF THE NIGHT. NAM SOUNDINGS
ALSO SUGGEST ENOUGH MOISTURE IN THE DENDRITIC GROWTH ZONE FOR SNOW...ALBEIT
VERY LIGHT FOR A PERIOD OVERNIGHT. DO NOT THINK IT WILL BE ENOUGH
FOR ANY ACCUMULATION BUT DID KEEP SLIGHT CHANCE WORDING THROUGH
MUCH OF THE NIGHT...AT LEAST UNTIL WEAK WARM ADVECTION/SUBSIDENCE
TAKES OVER.
FOR THE REMAINDER OF THE REGION...HIGH PRESSURE AND CLEARING SKIES
SHOULD HAVE INFLUENCE ON BRINGING DOWN TEMPERATURES OVERNIGHT AND
ACTUALLY WENT A DEGREE OR TWO COLDER THAN GUIDANCE AS THE BOUNDARY
LAYER DECOUPLES. THURSDAY...HIGH PRESSURE WILL REMAIN THE DOMINANT
PLAYER WITH WARM ADVECTION AND LOW LEVEL MIXING HELPING TO
MODERATE TEMPERATURES CLOSER TO NORMAL. A WEAK BACKDOOR COLD
FRONT DROPS INTO SRN NY/NRN PA FRIDAY...BUT MOISTURE IS LIMITED SO
NO SIGNIFICANT PRECIPITATION IS EXPECTED. SLOWLY MODERATING TEMPS
EXPECTED THROUGH THE PERIOD AS WELL.
&&
.LONG TERM /FRIDAY NIGHT THROUGH TUESDAY/...
SATURDAY SHOULD BE DRY WITH ABOVE NORMAL TEMPS. A COLD FRONT WILL
APPROACH FROM THE WEST ON SUNDAY INTO SUNDAY EVENING...BRINGING A
CHANCE OF RAIN SHOWERS. THERE IS MODEL DISAGREEMENT ON WHETHER THE
FRONT WILL STALL ACROSS THE OHIO VALLEY REGION. FOR NOW PREFER A
DRY FORECAST WITH THE FRONT CLEARING THE AREA. SEEMS LIKE A MORE
LIKELY SOLUTION CONSIDERING H5 FLOW AND RIDGING BUILDING IN
MONDAY. THE NEXT COLD FRONT WILL APPROACH FROM THE WEST
TUESDAY...BUT SHOULD NOT MOVE INTO THE LOCAL AREA UNTIL TUESDAY
NIGHT. TEMPERATURES SHOULD CONTINUE TO BE ABOVE NORMAL THROUGH THE
LONG TERM PERIOD.
&&
.AVIATION /17Z WEDNESDAY THROUGH SUNDAY/...
PER RECENT SURFACE AND SATELLITE DATA COUPLED WITH RECENT RAP AND
SREF MODEL OUTPUT...EXPECT COMBINATION OF VFR STRATOCUMULUS AND
ALTOCUMULUS TO MAINTAIN BROKEN COVERAGE ACROSS THE UPPER OHIO
VALLEY TODAY. ENSUING HIGH PRESSURE SUBSIDENCE WILL ENSURE NO
MORE THAN CIRRUS CLOUDS TONIGHT INTO THURSDAY SO VFR WILL
CONTINUE.
WINDS WILL BECOME MORE WESTERLY TODAY...INCREASING TO 12 KTS BY
MIDDAY.
.OUTLOOK.../THURSDAY NIGHT THROUGH SUNDAY/...
HIGH PRESSURE AND VFR CONDITIONS WILL CONTINUE THROUGH FRIDAY.
THERE IS A SLIGHT CHANCE OF RESTRICTIONS FRIDAY NIGHT INTO EARLY
SATURDAY DUE TO WARM FRONTAL RAIN SHOWERS. VFR CONDITIONS WILL
THEN PREVAIL FOR THE REMAINDER OF THE WEEKEND.
&&
.PBZ WATCHES/WARNINGS/ADVISORIES...
MD...NONE.
OH...NONE.
PA...NONE.
WV...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS PITTSBURGH PA
823 AM EST WED NOV 28 2012
.SYNOPSIS...
MIDWEST HIGH PRESSURE WILL PROMOTE DRY WEATHER INTO FRIDAY.
TEMPERATURES WILL BE SLIGHTLY COLDER THAN NORMAL TONIGHT AND
WEDNESDAY...BUT THEN MODERATE THURSDAY AND FRIDAY.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
PER RECENT SURFACE AND SATELLITE DATA...HAVE AGAIN ADJUSTED CLOUD
COVERAGE...INDICATING A MOSTLY CLOUDY DAY ACROSS THE UPPER OHIO
VALLEY. SREF AND RAP MODEL OUTPUT CONTINUE TO SHOW A SECONDARY COLD
FRONT PASSING EASTWARD THROUGH THE GREAT LAKES TODAY. ASSOCIATED
SHOWERS SHOULD PASS NORTH OF I-80 BUT REINFORCED SHALLOW COLD POOL
INSTABILITY WILL MAINTAIN CLOUDS ACROSS THE UPPER OHIO VALLEY TODAY.
MADE ONLY SMALL ADJUSTMENTS TO TEMPERATURE BASED ON RECENT SURFACE
DATA AND GFS LAMP AND RAP MODEL OUTPUT...THAT CONTINUED TO SHOW
HIGH TEMPERATURES THIS AFTERNOON ABOUT 5 DEGREES COLDER THAN
NORMAL.
DAYTIME VERTICAL MIXING WILL HELP SPEED UP WESTERLY WINDS THIS
AFTERNOON WITH GUSTS OF 20 TO 25 MPH POSSIBLE.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH FRIDAY/...
H8 FLOW WILL REMAIN OUT OF THE NW...WITH THE COLD AIR NOT
BEGINNING ITS RETREAT UNTIL LATE TONIGHT. THIS WILL KEEP IN CLOUDS
ACROSS MUCH OF THE AREA TONIGHT WITH THE POTENTIAL FOR SOME SCT
FLURRIES ACROSS THE NW.
HIGH PRESSURE THEN BUILDS IN THROUGH THURSDAY NIGHT. A WEAK
BACKDOOR COLD FRONT DROPS INTO SRN NY/NRN PA FRIDAY...BUT
MOISTURE IS LIMITED SO NO SIGNIFICANT PRECIPITATION IS EXPECTED.
SLOWLY MODERATING TEMPS EXPECTED THROUGH THE PERIOD AS WELL.
&&
.LONG TERM /FRIDAY NIGHT THROUGH TUESDAY/...
SATURDAY SHOULD BE DRY WITH ABOVE NORMAL TEMPS. A COLD FRONT WILL
APPROACH FROM THE WEST ON SUNDAY INTO SUNDAY EVENING...BRINGING A
CHANCE OF RAIN SHOWERS. THERE IS MODEL DISAGREEMENT ON WHETHER THE
FRONT WILL STALL ACROSS THE OHIO VALLEY REGION. FOR NOW PREFER A
DRY FORECAST WITH THE FRONT CLEARING THE AREA. SEEMS LIKE A MORE
LIKELY SOLUTION CONSIDERING H5 FLOW AND RIDGING BUILDING IN
MONDAY. THE NEXT COLD FRONT WILL APPROACH FROM THE WEST
TUESDAY...BUT SHOULD NOT MOVE INTO THE LOCAL AREA UNTIL TUESDAY
NIGHT. TEMPERATURES SHOULD CONTINUE TO BE ABOVE NORMAL THROUGH THE
LONG TERM PERIOD.
&&
.AVIATION /13Z WEDNESDAY THROUGH SUNDAY/...
PER RECENT SURFACE AND SATELLITE DATA COUPLED WITH RECENT RAP AND
SREF MODEL OUTPUT...EXPECT COMBINATION OF VFR STRATOCUMULUS AND
ALTOCUMULUS TO MAINTAIN BROKEN COVERAGE ACROSS THE UPPER OHIO
VALLEY TODAY. ENSUING HIGH PRESSURE SUBSIDENCE WILL ENSURE NO
MORE THAN CIRRUS CLOUDS TONIGHT INTO THURSDAY SO VFR WILL
CONTINUE.
WINDS WILL BECOME MORE WESTERLY TODAY...INCREASING TO 12 KTS BY
MIDDAY.
.OUTLOOK.../THURSDAY NIGHT THROUGH SUNDAY/...
HIGH PRESSURE AND VFR CONDITIONS WILL CONTINUE THROUGH FRIDAY.
THERE IS A SLIGHT CHANCE OF RESTRICTIONS FRIDAY NIGHT INTO EARLY
SATURDAY DUE TO WARM FRONTAL RAIN SHOWERS. VFR CONDITIONS WILL
THEN PREVAIL FOR THE REMAINDER OF THE WEEKEND.
&&
.PBZ WATCHES/WARNINGS/ADVISORIES...
MD...NONE.
OH...NONE.
PA...NONE.
WV...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS PITTSBURGH PA
640 AM EST WED NOV 28 2012
.SYNOPSIS...
MIDWEST HIGH PRESSURE WILL PROMOTE DRY WEATHER INTO FRIDAY.
TEMPERATURES WILL BE SLIGHTLY COLDER THAN NORMAL TONIGHT AND
WEDNESDAY...BUT THEN MODERATE THURSDAY AND FRIDAY.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
UPDATED FOR MINOR ADJUSTMENTS FOR CLOUD COVER. LATEST HRRR SHOWS
THE STRATOCU DECK CONTINUING TO ERODE FROM WEST TO THE EAST. WOULD
EXPECT PARTLY SUNNY SKIES THIS MORNING ACROSS MUCH OF THE REGION.
HOWEVER...WITH COLD AIR ALOFT AND 85H WINDS BACKING TO THE NW
...SCT-BKN CU SHOULD REDEVELOP THIS AFTERNOON. LATEST RAP FORECAST
SOUNDINGS REINFORCE THE IDEA OF CLOUD DEVELOPMENT WITH DAYTIME
HEATING.
TEMPS WILL REMAIN BELOW NORMAL.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH FRIDAY/...
H8 FLOW WILL REMAIN OUT OF THE NW...WITH THE COLD AIR NOT
BEGINNING ITS RETREAT UNTIL LATE TONIGHT. THIS WILL KEEP IN CLOUDS
ACROSS MUCH OF THE AREA TONIGHT WITH THE POTENTIAL FOR SOME SCT
FLURRIES ACROSS THE NW.
HIGH PRESSURE THEN BUILDS IN THROUGH THURSDAY NIGHT. A WEAK
BACKDOOR COLD FRONT DROPS INTO SRN NY/NRN PA FRIDAY...BUT
MOISTURE IS LIMITED SO NO SIGNIFICANT PRECIPITATION IS EXPECTED.
SLOWLY MODERATING TEMPS EXPECTED THROUGH THE PERIOD AS WELL.
&&
.LONG TERM /FRIDAY NIGHT THROUGH TUESDAY/...
SATURDAY SHOULD BE DRY WITH ABOVE NORMAL TEMPS. A COLD FRONT WILL
APPROACH FROM THE WEST ON SUNDAY INTO SUNDAY EVENING...BRINGING A
CHANCE OF RAIN SHOWERS. THERE IS MODEL DISAGREEMENT ON WHETHER THE
FRONT WILL STALL ACROSS THE OHIO VALLEY REGION. FOR NOW PREFER A
DRY FORECAST WITH THE FRONT CLEARING THE AREA. SEEMS LIKE A MORE
LIKELY SOLUTION CONSIDERING H5 FLOW AND RIDGING BUILDING IN
MONDAY. THE NEXT COLD FRONT WILL APPROACH FROM THE WEST
TUESDAY...BUT SHOULD NOT MOVE INTO THE LOCAL AREA UNTIL TUESDAY
NIGHT. TEMPERATURES SHOULD CONTINUE TO BE ABOVE NORMAL THROUGH THE
LONG TERM PERIOD.
&&
.AVIATION /12Z WEDNESDAY THROUGH SUNDAY/...
CONTINUED SUBSIDENCE FROM HIGH PRESSURE WILL ALLOW MVFR CEILINGS
TO BREAK THIS MORNING WITH VFR CONDITIONS TO PREVAIL ACROSS THE
TERMINALS FOR THE REMAINDER OF THE TAF PERIOD. WINDS WILL BECOME
MORE WESTERLY TODAY...INCREASING TO 5 TO 10KTS BY LATE MORNING.
.OUTLOOK.../WEDNESDAY NIGHT THROUGH SUNDAY/...
HIGH PRESSURE AND VFR CONDITIONS WILL CONTINUE THROUGH FRIDAY.
THERE IS A SLIGHT CHANCE OF RESTRICTIONS FRIDAY NIGHT INTO EARLY
SATURDAY DUE TO WARM FRONTAL RAIN SHOWERS. VFR CONDITIONS WILL
THEN PREVAIL FOR THE REMAINDER OF THE WEEKEND.
&&
.PBZ WATCHES/WARNINGS/ADVISORIES...
MD...NONE.
OH...NONE.
PA...NONE.
WV...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS PITTSBURGH PA
417 AM EST WED NOV 28 2012
.SYNOPSIS...
MIDWEST HIGH PRESSURE WILL PROMOTE DRY WEATHER INTO FRIDAY.
TEMPERATURES WILL BE SLIGHTLY COLDER THAN NORMAL TONIGHT AND
WEDNESDAY...BUT THEN MODERATE THURSDAY AND FRIDAY.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
LATEST HRRR SHOWS THE STRATOCU DECK CONTINUING TO ERODE TO THE
EAST. WOULD EXPECT PARTLY TO MOSTLY SUNNY SKIES THIS MORNING
ACROSS MUCH OF THE REGION. HOWEVER...WITH COLD AIR ALOFT AND 85H
WINDS BACKING TO THE NW...SCT-BKN CU SHOULD REDEVELOP THIS
AFTERNOON. LATEST RAP FORECAST SOUNDINGS REINFORCE THE IDEA OF
CLOUD DEVELOPMENT WITH DAYTIME HEATING.
TEMPS WILL REMAIN BELOW NORMAL.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH FRIDAY/...
H8 FLOW WILL REMAIN OUT OF THE NW...WITH THE COLD AIR NOT
BEGINNING ITS RETREAT UNTIL LATE TONIGHT. THIS WILL KEEP IN CLOUDS
ACROSS MUCH OF THE AREA TONIGHT WITH THE POTENTIAL FOR SOME SCT
FLURRIES ACROSS THE NW.
HIGH PRESSURE THEN BUILDS IN THROUGH THURSDAY NIGHT. A WEAK
BACKDOOR COLD FRONT DROPS INTO SRN NY/NRN PA FRIDAY...BUT
MOISTURE IS LIMITED SO NO SIGNIFICANT PRECIPITATION IS EXPECTED.
SLOWLY MODERATING TEMPS EXPECTED THROUGH THE PERIOD AS WELL.
&&
.LONG TERM /FRIDAY NIGHT THROUGH TUESDAY/...
SATURDAY SHOULD BE DRY WITH ABOVE NORMAL TEMPS. A COLD FRONT WILL
APPROACH FROM THE WEST ON SUNDAY INTO SUNDAY EVENING...BRINGING A
CHANCE OF RAIN SHOWERS. THERE IS MODEL DISAGREEMENT ON WHETHER THE
FRONT WILL STALL ACROSS THE OHIO VALLEY REGION. FOR NOW PREFER A
DRY FORECAST WITH THE FRONT CLEARING THE AREA. SEEMS LIKE A MORE
LIKELY SOLUTION CONSIDERING H5 FLOW AND RIDGING BUILDING IN
MONDAY. THE NEXT COLD FRONT WILL APPROACH FROM THE WEST
TUESDAY...BUT SHOULD NOT MOVE INTO THE LOCAL AREA UNTIL TUESDAY
NIGHT. TEMPERATURES SHOULD CONTINUE TO BE ABOVE NORMAL THROUGH THE
LONG TERM PERIOD.
&&
.AVIATION /09Z WEDNESDAY THROUGH SUNDAY/...
CONTINUED SUBSIDENCE FROM HIGH PRESSURE WILL ALLOW CEILINGS TO
BREAK BY MID-MORNING WITH VFR CONDITIONS TO PREVAIL ACROSS THE
TERMINALS FOR THE REMAINDER OF THE TAF PERIOD. NORTHWESTERLY WINDS
WILL BECOME NEAR CALM OVERNIGHT. WINDS WILL BECOME MORE WESTERLY
ON WEDNESDAY...INCREASING TO 5 TO 10KTS BY LATE MORNING.
.OUTLOOK.../WEDNESDAY NIGHT THROUGH SUNDAY/...
HIGH PRESSURE AND VFR CONDITIONS WILL CONTINUE THROUGH FRIDAY.
THERE IS A SLIGHT CHANCE OF RESTRICTIONS FRIDAY NIGHT INTO EARLY
SATURDAY DUE TO WARM FRONTAL RAIN SHOWERS. VFR CONDITIONS WILL
THEN PREVAIL FOR THE REMAINDER OF THE WEEKEND.
&&
.PBZ WATCHES/WARNINGS/ADVISORIES...
MD...NONE.
OH...NONE.
PA...NONE.
WV...NONE.
&&
$$
AREA FORECAST DISCUSSION...UPDATED
NWS PITTSBURGH PA
1232 AM EST WED NOV 28 2012
.SYNOPSIS...
MIDWEST HIGH PRESSURE WILL PROMOTE DRY WEATHER INTO FRIDAY.
TEMPERATURES WILL BE SLIGHTLY COLDER THAN NORMAL TONIGHT AND
WEDNESDAY...BUT THEN MODERATE THURSDAY AND FRIDAY.
&&
.NEAR TERM /THROUGH TODAY/...
STRATOCU CONTINUES TO FILL INTO THE WEST...LIKELY AS A RESULT OF A
WEAK SHORTWAVE TROUGH MOVING THROUGH. WOULD EXPECT THE WESTERN
EDGE OF THE CLOUD DECK TO BEGIN TO DECAY AS DRIER AIR FURTHER WEST
SLOWLY MOVES EASTWARD. LATEST RAP SOUNDINGS ARE SHOWING THE LOWER
LEVELS DRYING OUT AS THE NIGHT PROGRESSES...WITH ZZV SOON AFTER
ISSUANCE TIME...BUT PIT AND MGW NOT UNTIL AFTER DAWN. THIS APPEARS
TO BE REASONABLE AS FAR AS TIMING GOES AND WILL STICK CLOSE TO
THIS FOR THE FORECAST.
TROUGH AXIS WILL SHIFT EASTWARD LATER THIS MORNING AND LL FLOW
WILL BACK TO THE NW. THERE WILL ALSO BE ANOTHER SHOT OF CAA. THIS
SHOULD PROVIDE ANOTHER INCREASE IN CLOUDS THIS AFTERNOON AND KEEP
TEMPS BELOW NORMAL.
&&
.SHORT TERM /TONIGHT THROUGH FRIDAY/...
H8 FLOW WILL REMAIN OUT OF THE NW...WITH THE COLD AIR NOT
BEGINNING ITS RETREAT UNTIL LATE TONIGHT. THIS WILL KEEP IN CLOUDS
ACROSS MUCH OF THE AREA TONIGHT WITH THE POTENTIAL FOR SOME SCT
FLURRIES ACROSS THE NW.
HIGH PRESSURE THEN BUILDS IN THROUGH THURSDAY NIGHT. A WEAK
BACKDOOR COLD FRONT DROPS INTO SRN NY/NRN PA FRIDAY...BUT
MOISTURE IS LIMITED SO NO SIGNIFICANT PRECIPITATION IS EXPECTED.
SLOWLY MODERATING TEMPS EXPECTED THROUGH THE PERIOD AS WELL.
&&
.LONG TERM /FRIDAY NIGHT THROUGH TUESDAY/...
SATURDAY SHOULD BE DRY WITH ABOVE NORMAL TEMPS. A COLD FRONT WILL
APPROACH FROM THE WEST ON SUNDAY INTO SUNDAY EVENING...BRINGING A
CHANCE OF RAIN SHOWERS. THERE IS MODEL DISAGREEMENT ON WHETHER THE
FRONT WILL STALL ACROSS THE OHIO VALLEY REGION. FOR NOW PREFER A
DRY FORECAST WITH THE FRONT CLEARING THE AREA. SEEMS LIKE A MORE
LIKELY SOLUTION CONSIDERING H5 FLOW AND RIDGING BUILDING IN
MONDAY. THE NEXT COLD FRONT WILL APPROACH FROM THE WEST
TUESDAY...BUT SHOULD NOT MOVE INTO THE LOCAL AREA UNTIL TUESDAY
NIGHT. TEMPERATURES SHOULD CONTINUE TO BE ABOVE NORMAL THROUGH THE
LONG TERM PERIOD.
&&
.AVIATION /05Z WEDNESDAY THROUGH SUNDAY/...
A STRATOCUMULUS DECK WILL PREVAIL ACROSS ALL OF THE TERMINALS
EXCEPT KZZV OVERNIGHT AS LOW-LEVEL MOISTURE BECOMES TRAPPED UNDER
AN INVERSION. CEILINGS WILL PREVAIL MOSTLY AT 2500-3000FT
OVERNIGHT WITH THE CLOCK DECK BEGINNING TO ERODE FROM THE WEST
AROUND DAWN.
CONFIDENCE IN HOW LONG CEILINGS WILL PREVAIL OVERNIGHT IS LOW AS
LAMP/HRRR/NARRE-TL GUIDANCE INDICATE CEILINGS ERODING FROM THE
WEST AND BREAKING ACROSS THE TERMINALS BY 06Z. THE
TAFS...HOWEVER...INDICATE MVFR PREVAILING UNTIL AROUND 12Z WITH
THE SUPPORT OF RECENT SATELLITE TRENDS AND MODEL SOUNDINGS.
SUBSIDENCE FROM HIGH PRESSURE BUILDING IN FROM THE SOUTHWEST WILL
ALLOW CEILINGS TO BREAK BY MID-MORNING WEDNESDAY WITH VFR
CONDITIONS TO PREVAIL ACROSS THE TERMINALS FOR THE REMAINDER OF
THE TAF PERIOD. NORTHWESTERLY WINDS WILL BECOME NEAR CALM
OVERNIGHT. WINDS WILL BECOME MORE WESTERLY ON
WEDNESDAY...INCREASING TO 5 TO 10KTS BY LATE MORNING.
.OUTLOOK.../WEDNESDAY NIGHT THROUGH SUNDAY/...
HIGH PRESSURE AND VFR CONDITIONS WILL CONTINUE THROUGH FRIDAY.
THERE IS A SLIGHT CHANCE OF RESTRICTIONS FRIDAY NIGHT INTO EARLY
SATURDAY DUE TO WARM FRONTAL RAIN SHOWERS. VFR CONDITIONS WILL
THEN PREVAIL FOR THE REMAINDER OF THE WEEKEND.
&&
.PBZ WATCHES/WARNINGS/ADVISORIES...
MD...NONE.
OH...NONE.
PA...NONE.
WV...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS DULUTH MN
556 PM CST THU NOV 29 2012
.UPDATE...
VERY LIGHT SNOW/FLURRIES WERE FALLING IN THE DULUTH AREA DUE TO
NORTHEAST WINDS DOWN LAKE SUPERIOR.
WE`VE RECEIVED A COUPLE SHIP REPORTS OF WATER TEMPERATURES OF
5C...AND BOTH THE RUC AND NAM SHOW 850MB TEMPS FROM -12C TO -5C
FROM GRAND PORTAGE TO THE TWIN PORTS. BUFR SOUNDINGS INDICATE
INVERSION LEVELS ARE RATHER LOW. WE INCREASED POPS A BIT
TONIGHT...MAINLY ALONG THE NORTH SHORE...AND BEEFED UP THE MENTION
OF FREEZING DRIZZLE AS WELL.
LOW LEVEL FLOW IS FORECAST TO VEER THROUGH THE EVENING TO MORE
E-SE...SHIFTING THE FOCUS FOR LES TO THE NORTH SHORE FROM THE TWIN
PORTS. WE DON`T EXPECT SIGNIFICANT ACCUMULATION TO OCCUR AROUND
KDLH AS THE LOWER DELTA-T`S AND INVERSION LEVELS ARE NOT THAT
FAVORABLE. THINGS DO COME TOGETHER MORE ALONG THE NORTH
SHORE...ESPECIALLY NORTH AND EAST OF SILVER BAY FROM LATE EVENING
ON. SOME SNOW ACCUMULATION WILL BE POSSIBLE UP THERE...AND WE`LL
HAVE 1-3 INCH AMOUNTS...WITH SOME LOCALIZED HIGHER AMOUNTS. WE`LL
MONITOR THE NORTH SHORE CLOSELY FOR HIGHER SNOW AMOUNTS.
FORECAST SOUNDINGS LOOK FAVORABLE FOR FREEZING DRIZZLE OVER THE
SOUTHERN HALF/TWO THIRDS OF THE CWA OVERNIGHT...THOUGH
PRECIPITATION AMOUNTS DO LOOK TO BE LIMITED. HOWEVER...IT ONLY
TAKES A LITTLE FREEZING PRECIPITATION TO GET SOME SLICK ROADS.
&&
.AVIATION...00Z TAFS
IFR AND MVFR CEILINGS COVERED MOST OF THE NORTHLAND THIS
EVENING...WITH SOME VFR CONDITIONS IN THE FAR NORTH/NORTHEAST. WE
EXPECT CEILINGS TO LOWER ALL AREAS OVERNIGHT...WITH MOST
EXPERIENCING IFR CONDITIONS BY 12Z. WAA AND A WEAK SHORTWAVE WILL
COMBINE TO BRING THE THREAT FOR LIGHT PRECIPITATION OVERNIGHT.
FORECAST SOUNDINGS LOOK FAVORABLE FOR FREEZING DRIZZLE AS THERE IS
A DRY LAYER PRESENT AND THE MOIST LAYER IS MOSTLY WARMER THAN
-10C. WE DID ADD FREEZING DRIZZLE TO THE KDLH/KHIB/KHYR TAFS
TONIGHT. FOG WILL DEVELOP OVERNIGHT INTO FRIDAY AS WELL WITH
INCREASING MOISTURE.
&&
.PREV DISCUSSION... /ISSUED 256 PM CST THU NOV 29 2012/
SHORT TERM...TONIGHT THROUGH FRIDAY NIGHT
THE MAIN CONCERN FOR THE SHORT TERM PERIOD WILL BE PRECIPITATION
TYPE ISSUES INTO FRIDAY. AREA SOUNDINGS AND BUFKIT PROFILES DEPICT
SOME FREEZING DRIZZLE ESPECIALLY FOR THE SOUTHERN HALF OF THE
FORECAST AREA. ANY FREEZING DRIZZLE THAT FALLS WILL BE VERY LIGHT
AND SPOTTY. ANOTHER CONCERN WILL BE FOR LAKE EFFECT SNOW AS WINDS
WILL BECOME MORE EASTERLY TONIGHT. TEMPERATURE PROFILES FAVOR ALL
SNOW FOR THE NORTH SHORE WHERE SNOW ACCUMULATIONS COULD REACH AROUND
AN INCH TONIGHT. THE LAKE EFFECT SNOW SHOWERS WILL DIMINISH AND SHIFT
INTO THE ARROWHEAD ONCE WINDS BECOME SOUTHEASTERLY EARLY FRIDAY. A
WEAK SHORTWAVE APPROACHING FROM THE WEST WILL CONTINUE TO BRING A
SLIGHT CHANCE OF LIGHT SNOW SHOWERS AND PATCHY FREEZING DRIZZLE OVER
THE NORTHERN HALF OF THE FORECAST AREA THROUGH FRIDAY NIGHT.
TEMPERATURES ON FRIDAY WILL RISE TO THE MIDDLE 30S OVER THE FAR
SOUTHERN PORTIONS OF THE AREA ENDING THE FREEZING DRIZZLE THREAT.
WARM AIR ADVECTION FROM THE SOUTH OVER THE SNOW COVERED GROUND WILL
LEAD TO AREAS OF FOG OVER MOST OF THE FORECAST AREA ON FRIDAY NIGHT.
LONG TERM...SATURDAY THROUGH TUESDAY...
MID LVL RIDGE BREAKS DOWN ALONG PACNW COAST ALLOWING A RAPID INFLUX
OF MILD AIR TO SPREAD INLAND TO NRN CONUS FROM SATURDAY INTO MONDAY.
A WEAK SYSTEM...SFC/ALOFT...WILL PROGRESS FROM THE NRN PLAINS INTO
THE GT LAKES SATURDAY WITH LIGHT PRECIP EXPECTED. MAY SEE SOME
RESIDUAL FZRA/SN OVER INTERIOR OF THE ARROWHEAD SATURDAY AS
RETREATING COLD DOME IS TOPPED BY WARM AIR ADVECTION. WEAK COLD
FRONT MAY ALLOW BRIEF TRANSITION TO RA/SN OVER NRN TIER OF MN ZONES
EARLY SUNDAY. NEXT SYSTEM HAS MUCH STRONGER DYNAMICS ALOFT AND WILL
INTENSIFY AS IT MOVES FROM NODAK INTO WRN ONTARIO MONDAY. SIGNIFICANT
PUSH OF WARM AIR WILL KEEP PTYPE IN THE LIQUID FORM MONDAY BEFORE
CHANGING TO SNOW MONDAY NIGHT OVER MN ZONES. ALTHOUGH THERE WILL BE
SIGNIFICANT COLD AIR ADVECTION BEHIND THE SYSTEM TUESDAY...THE
PROGRESSIVE NATURE OF THE FLOW ALOFT APPEARS TO MAKE A CASE FOR A
RETURN TO ANOMALOUS WARMTH FOR LATE IN THE WEEK.
&&
.POINT TEMPS/POPS...
DLH 19 32 29 39 / 30 30 20 50
INL 11 29 26 37 / 40 30 20 40
BRD 21 33 29 41 / 20 20 10 40
HYR 22 33 31 43 / 20 20 10 50
ASX 23 32 30 43 / 30 20 20 40
&&
.DLH WATCHES/WARNINGS/ADVISORIES...
MN...NONE.
WI...NONE.
LS...SMALL CRAFT ADVISORY UNTIL 6 PM CST FRIDAY FOR LSZ121-140>148.
&&
$$
SHORT TERM...MELDE/KK
LONG TERM....CANNON
AVIATION...MELDE
AREA FORECAST DISCUSSION
NWS TWIN CITIES/CHANHASSEN MN
300 PM CST WED NOV 28 2012
.DISCUSSION...
WITH AFTERNOON SUN AFTER DISSIPATION OF MORNING STRATUS TEMPS HAVE
BEBOUNDED QUITE NICELY INTO THE MID 30S TO AROUND 40. HIGH PRESSURE
BUILDING SE ACROSS THE CANADIAN PRAIRIES INTO N MN WILL BACKDOOR A
COLD FRONT ACROSS THE AREA TONIGHT AND THURSDAY MORNING. THIS WILL
BRING IN SLIGHTLY COOLER TEMPS TOMORROW ACROSS NORTHERN CWA...BUT
SOUTHERN AREAS SHOULD STILL BE ABLE TO REACH AROUND 40. NOT
EXPECTING ANY PCPN WITH THIS SYSTEM...BUT A FEW FLURRIES CUD BE
SHAKEN OUT TO OUR NORTH.
500 MB HEIGHTS SHOWED NICE RISES LAST 24 HOURS AS TROF OVER E GREAT
LAKES INTO E CANADA CONTINUES TO SLIDE EAST AND PATTERN BECOMES MORE
ZONAL NEXT FEW DAYS CARRYING A FEW WEAK WAVES THRU OUR REGION. FIRST
WAVE COMES THRU THE NORTHERN ROCKIES TONIGHT REACHING W MN BY 06Z
FRIDAY...MOVING ACROSS OUR AREA DURING THE DAY ON FRIDAY. LOW
LEVELS MOISTEN UP AHEAD OF THIS FEATURE WITH MODELS CONTINUING TO
SPILT OUT LIGHT QPF. WILL CONTINUE WITH THE THEME OF PSBL FRZG DZL
ACROSS AREA LATE THURSDAY NIGHT AND FRIDAY MRNG IN MOIST EASTERLY
FLOW NORTH OF FRONT WHICH BY THEN WILL LIE ACROSS S IA. TEMPS ON
FRIDAY WILL LIKELY BE DAMPERED BY STRATUS ACROSS AREA.
SOUTHERLY FLOW INCREASES ON SATURDAY AHEAD OF NEXT WAVE BRINGING
ANOTHER PUSH OF WARM AIR AND CHC -RA INTO AREA. EXPECT THAT PCPN
WON`T BEGIN UNTIL AFTER SURFACE TEMPS WARM ABOVE FREEZING WITH BEST
FORCING NOT DEVELOPING UNTIL LATE MORNING AND INTO THE EARLY EVENING
WHEN UPPER TROF MOVES THRU. CLOUD COVER WILL AGAIN SUPPRESS MAX
TEMPS WITH HIGHS REMAINING MAINLY IN THE 40S.
A BIT OF A COOL PUSH BEHIND THE FRONT COMING THRU ON SATURDAY...BUT
SHUD SEE SOME SUN ON SUNDAY AS NARROW RIDGE OF HIGH PRESSURE BUILDS
INTO AREA. WITH SOME SUNSHINE...TEMPS SHUD WARM A FEW DEGREES
SUNDAY OVER SATURDAY`S HIGHS.
STRONG PACIFIC TROF PLOWS ACROSS THE DAKOTAS ON MONDAY WITH STRONG
SOUTH FLOW INTO OUR REGION. A VERY MILD START TO THE DAY WITH MUCH
OF THE AREA STARTING OUT THE DAY AOA 40 DEGREES. WITH SUN...COULD
SEE SOME TEMPS NEAR 60 IN SC MN...BUT SOUTH WINDS BRING SLUG OF
MOISTURE NORTH WHICH WILL MAKE FOR A CLOUDY DAY. WILL PLAY HIGHEST
POPS WITH THIS SYSTEM IN EASTERN AREAS WHERE BEST MOISTURE TRANSPORT
AND HENCE HIGHEST PWAT. COLD FRONT PLOWS INTO AREA DURING THE DAY
MONDAY WHICH MAY BRING FALLING AFTERNOON TEMPS IN WESTERN AREAS.
STRONG PUSH OF COLD AIR BEHIND THIS SYSTEM. GFS DRIVES COLD POCKET
A BIT FARTHER S THAN ECMWF...BUT EITH SOLUTION WOULD BRING TEMPS
TUESDAY/WEDNESDAY ABOUT 30 DEGREES COLDER THAN MONDAY.
&&
.AVIATION.../18Z TAF ISSUANCE/
WITH RIDGE AXIS SHIFTING EAST THIS MORNING...SW RETURN FLOW HAS
SET UP...WHICH HAS ALLOWED MORNING MVFR CIGS TO RETREAT NE WITH
ONLY EAU HAVING TO DEAL WITH THEM THROUGH 19Z. THESE CIGS WILL
CONTINUE NORTH UNTIL THEY RUN INTO A COLD FRONT THAT IS NOW
SLIPPING THROUGH WRN NODAK AND SRN MANITOBA. THIS FRONT WILL WORK
INTO THE MPX AREA LATE TONIGHT THROUGH THU MORNING...BRINGING WITH
IT A GRADUAL WIND SHIFT OVER TO THE NE AND POSSIBLY ANOTHER BATCH
OF IFR/MVFR CIGS. CONFIDENCE IN CIGS FOR LATE IN THE TAF PERIOD IS
NOT INCREDIBLY HIGH. LOW LEVEL RH BEHIND THE COLD FRONT DOES
INCREASE...WITH THE GFS/NAM CERTAINLY SHOWING THE POSSIBILITY OF
LOW CIGS COMING INTO CENTRAL MN AROUND 10Z AND SAGGING DOWN TO
ABOUT MSP/EAU A LITTLE AFTER 18Z. WHAT LED TO GOING WITH THE
STRATUS THOUGH WAS THE SREF. PROB FOR CIGS LESS THAN 3K FT INCS TO
OVER 80% WITH THE POST FRONTAL CLOUD BAND AND GIVEN THAT...DECIDED
TO PUT THE CIGS IN. THIS MOISTURE IS AT 925 MB OR LOWER...SO IF WE
DO SEE CIGS...THEY WOULD BE IN THE 005-015 RANGE. CONFIDENCE IN
LOWER CIGS REALLY INCS AFTER 00Z FRI.
KMSP...GOOD CONDITIONS EXPECTED THROUGH 18Z THU...BUT AFTER
THAT...CONFIDENCE IN TAF DOES DECREASE. FOR NOW...INCLUDED SUB 017
CIGS THU AFTERNOON WITH A TIMING THAT WAS A COMPROMISE BETWEEN
SREF /18Z/ AND NAM /00Z/. HRRR ALONG WITH THE RAP SHOW A NICE
BAND OF LOWER CIGS DROPPING SOUTH WITH THE FRONT OVER NRN MN
TONIGHT AND IF WE DO SEE THE CIGS...COULD CERTAINLY OCCUR PRIOR TO
20Z...BUT CONFIDENCE IN THE OCCURRENCE/TIMING OF THE CIGS SHOULD
INCREASE TONIGHT WHEN WE GET A BETTER IDEA OF HOW THE POST FRONTAL
STRATUS...IF IT IS THERE...WILL BEHAVE.
/OUTLOOK FOR KMSP/
FRI...IFR/MVFR CIGS. MRNG BR/FZDZ POSSIBLE. WINDS ESE 10KTS.
SAT...MVFR OR LOWER CIGS. CHANCE OF -RA. WINDS S 10 KTS.
SUN...VFR. WIND S 5 KTS.
&&
.MPX WATCHES/WARNINGS/ADVISORIES...
MN...NONE.
WI...NONE.
&&
$$
BAP/MPG
AREA FORECAST DISCUSSION
NWS TWIN CITIES/CHANHASSEN MN
1231 PM CST WED NOV 28 2012
.UPDATE...
18Z AVIATION DISCUSSION ADDED BELOW.
&&
.PREV DISCUSSION...
/ISSUED 613 AM CST WED NOV 28 2012/
MILD WEATHER WILL CONTINUE ACROSS THE REGION FOR THE REST OF THE
WEEK. THE WARM WEATHER WILL END ON MONDAY AS THE UPPER MISSISSIPPI
RIVER VALLEY WILL BE IN THE WARM SECTOR OF A DEVELOPING SURFACE LOW.
THIS CYCLONE WILL DRIVE A COLD FRONT THROUGH THE REGION MONDAY NIGHT
WHICH WILL BE ACCOMPANIED BY STRONG NORTHWEST WINDS AND POTENTIALLY
SOME LIGHT SNOW.
TODAY THROUGH FRIDAY...EARLY MORNING WATER VAPOR IMAGERY TOGETHER
WITH 500MB HEIGHTS AND WINDS SHOWED NORTHWEST FLOW CENTERED ACROSS
NORTH AMERICA...WITH AN UPPER LEVEL RIDGE DRAPED ALONG THE SPINE OF
THE ROCKIES...AND AN IMPRESSIVE TRIO OF UPPER LEVEL LOWS IN THE GULF
OF ALASKA. AT THE SURFACE A BROAD AREA OF HIGH PRESSURE SPREAD
ACROSS THE NORTHERN PLAINS BENEATH THE UPPER LEVEL SUBSIDENCE
ASSOCIATED ANTICYCLONIC FLOW OF THE AFOREMENTIONED UPSTREAM RIDGE.
FURTHER WEST OFF THE CANADIAN COAST WERE TWO SUBSTANTIAL SURFACE
LOWS WITH MSLP OF 985 AND 972 RESPECTIVELY. THESE SURFACE CYCLONES
WERE A DIRECT RESULT OF UPPER LEVEL POSITIVE VORTICITY ADVECTION IN
THE REGION OF LOW STATIC STABILITY CHARACTERIZED BY THE RELATIVELY
WARM WATERS OF THE PACIFIC. GOING FORWARD...THE SOUTHERN MOST
WAVE...WHICH IS LOCATED ROUGHLY 500MI OUT TO SEA FROM THE CALIFORNIA
SHORELINE...WILL BECOME ORPHANED FROM THE POTENTIAL VORTICITY
RESERVOIR TO THE NORTH...AND GRADUALLY WEAKEN AS IT CROSSES THE
IDAHO ROCKIES AND REACHES THE MIDWEST THURSDAY AFTERNOON. ALTHOUGH
THIS FEATURES IS RATHER BENIGN AT FIRST GLANCE...THERE IS STILL SOME
UPPER LEVEL FORCING FOR ASCENT AS SEEN IN THE QVECT
DIVERGENCE...DRIVEN MAINLY BY THE Q_S VECTORS ON THE DOWNSTREAM SIDE
OF THE TROUGH AXIS...BUT ALSO WITH SOME CONTRIBUTION BY THE Q_N
ACROSS THE TEMPERATURE GRADIENT. THIS UPWARD FORCING WILL BE ENOUGH
TO INDUCE AN EAST SOUTHEASTERLY FLOW AT LOW LEVELS WHICH WILL BECOME
SATURATED AND...ACCORDING TO THE FORECAST SOUNDINGS...LOOKS
INCREASINGLY FAVORABLE FOR SOME FOG AND LIGHT FREEZING DRIZZLE LATE
THURSDAY NIGHT INTO FRIDAY MORNING. THIS IS ALSO SUPPORTED BY LAST
FEW RUNS OF THE SREF FREEZING RAIN PROBABILITIES. THE LIFT IS
WEAK...AND THE SATURATION LAYER IS ONLY A FEW THOUSAND FEET
THICK...SO NOT ANTICIPATING MUCH MORE THAN A FEW HUNDREDTHS OF TOTAL
QPF...BUT ENOUGH TO SLICKEN UP THE UNTREATED PAVED SURFACES FOR THE
FRIDAY MORNING COMMUTE.
SATURDAY THROUGH WEDNESDAY...ONCE THIS WAVE MOVES EASTWARD THE UPPER
LEVEL JET WILL BECOME MORE ZONAL WITH EMBEDDED SHORTWAVES EJECTING
OFF FROM THE LOW IN THE GULF OF ALASKA AND PERIODICALLY TRAVERSING
THE REGION LIKELY RESULTING IN NOTHING MORE THAN A FEW MID LEVEL
CLOUDS. SATURDAY SHOWS A BETTER POTENTIAL FOR SOME MEASURABLE
PRECIP...BUT THE THERMAL PROFILE SHOULD BE WARM ENOUGH THAT IT ALL
WILL FALL AS LIQUID. LOOKING AHEAD...AFTER SEVERAL OSCILLATIONS...A
STRIP OF PV WILL SWING ACROSS NEVADA ON SUNDAY AND DEVELOP A LOW
PRESSURE SYSTEM ON THE LEE SIDE OF THE ROCKIES. THE SOUTHERLY FLOW
AHEAD OF THIS WAVE WILL BRING ANOTHER REINFORCEMENT OF WARM AIR
WHICH WILL LAST THROUGH MONDAY. BY MONDAY NIGHT THE 28.00 ECMWF AND
GFS VARY CONSIDERABLY ON THE TRACK OF THE SURFACE LOW. THE GFS TAKES
IT INTO NORTHERN MINNESOTA...AND DRIVES A COLD FRONT THROUGH THE
REGION. IT IS MUCH DEEPER LOW...AND THEREFORE THE COLD ADVECTION IS
STRONGER WHICH IS WHY THE FORECAST SOUNDINGS SHOW LIGHT SNOW AND
30KT WINDS WITH THE POTENTIAL FOR 40KTS GUSTS ON TUESDAY. MEANWHILE
THE ECMWF IS FURTHER NORTH WITH LESS SENSIBLE WEATHER ACROSS THE
UPPER MIDWEST.
&&
.AVIATION.../18Z TAF ISSUANCE/
WITH RIDGE AXIS SHIFTING EAST THIS MORNING...SW RETURN FLOW HAS
SET UP...WHICH HAS ALLOWED MORNING MVFR CIGS TO RETREAT NE WITH
ONLY EAU HAVING TO DEAL WITH THEM THROUGH 19Z. THESE CIGS WILL
CONTINUE NORTH UNTIL THEY RUN INTO A COLD FRONT THAT IS NOW
SLIPPING THROUGH WRN NODAK AND SRN MANITOBA. THIS FRONT WILL WORK
INTO THE MPX AREA LATE TONIGHT THROUGH THU MORNING...BRINGING WITH
IT A GRADUAL WIND SHIFT OVER TO THE NE AND POSSIBLY ANOTHER BATCH
OF IFR/MVFR CIGS. CONFIDENCE IN CIGS FOR LATE IN THE TAF PERIOD IS
NOT INCREDIBLY HIGH. LOW LEVEL RH BEHIND THE COLD FRONT DOES
INCREASE...WITH THE GFS/NAM CERTAINLY SHOWING THE POSSIBILITY OF
LOW CIGS COMING INTO CENTRAL MN AROUND 10Z AND SAGGING DOWN TO
ABOUT MSP/EAU A LITTLE AFTER 18Z. WHAT LED TO GOING WITH THE
STRATUS THOUGH WAS THE SREF. PROB FOR CIGS LESS THAN 3K FT INCS TO
OVER 80% WITH THE POST FRONTAL CLOUD BAND AND GIVEN THAT...DECIDED
TO PUT THE CIGS IN. THIS MOISTURE IS AT 925 MB OR LOWER...SO IF WE
DO SEE CIGS...THEY WOULD BE IN THE 005-015 RANGE. CONFIDENCE IN
LOWER CIGS REALLY INCS AFTER 00Z FRI.
KMSP...GOOD CONDITIONS EXPECTED THROUGH 18Z THU...BUT AFTER
THAT...CONFIDENCE IN TAF DOES DECREASE. FOR NOW...INCLUDED SUB 017
CIGS THU AFTERNOON WITH A TIMING THAT WAS A COMPROMISE BETWEEN
SREF /18Z/ AND NAM /00Z/. HRRR ALONG WITH THE RAP SHOW A NICE
BAND OF LOWER CIGS DROPPING SOUTH WITH THE FRONT OVER NRN MN
TONIGHT AND IF WE DO SEE THE CIGS...COULD CERTAINLY OCCUR PRIOR TO
20Z...BUT CONFIDENCE IN THE OCCURRENCE/TIMING OF THE CIGS SHOULD
INCREASE TONIGHT WHEN WE GET A BETTER IDEA OF HOW THE POST FRONTAL
STRATUS...IF IT IS THERE...WILL BEHAVE.
/OUTLOOK FOR KMSP/
FRI...IFR/MVFR CIGS. MRNG BR/FZDZ POSSIBLE. WINDS ESE 10KTS.
SAT...MVFR OR LOWER CIGS. CHANCE OF -RA. WINDS S 10 KTS.
SUN...VFR. WIND S 5 KTS.
&&
.MPX WATCHES/WARNINGS/ADVISORIES...
MN...NONE.
WI...NONE.
&&
$$
JRB/MPG
AREA FORECAST DISCUSSION
NWS TWIN CITIES/CHANHASSEN MN
613 AM CST WED NOV 28 2012
.UPDATE...FOR 12Z AVIATION DISCUSSION BELOW
&&
.DISCUSSION.../ISSUED 328 AM CST WED NOV 28 2012/
MILD WEATHER WILL CONTINUE ACROSS THE REGION FOR THE REST OF THE
WEEK. THE WARM WEATHER WILL END ON MONDAY AS THE UPPER MISSISSIPPI
RIVER VALLEY WILL BE IN THE WARM SECTOR OF A DEVELOPING SURFACE LOW.
THIS CYCLONE WILL DRIVE A COLD FRONT THROUGH THE REGION MONDAY NIGHT
WHICH WILL BE ACCOMPANIED BY STRONG NORTHWEST WINDS AND POTENTIALLY
SOME LIGHT SNOW.
TODAY THROUGH FRIDAY...EARLY MORNING WATER VAPOR IMAGERY TOGETHER
WITH 500MB HEIGHTS AND WINDS SHOWED NORTHWEST FLOW CENTERED ACROSS
NORTH AMERICA...WITH AN UPPER LEVEL RIDGE DRAPED ALONG THE SPINE OF
THE ROCKIES...AND AN IMPRESSIVE TRIO OF UPPER LEVEL LOWS IN THE GULF
OF ALASKA. AT THE SURFACE A BROAD AREA OF HIGH PRESSURE SPREAD
ACROSS THE NORTHERN PLAINS BENEATH THE UPPER LEVEL SUBSIDENCE
ASSOCIATED ANTICYCLONIC FLOW OF THE AFOREMENTIONED UPSTREAM RIDGE.
FURTHER WEST OFF THE CANADIAN COAST WERE TWO SUBSTANTIAL SURFACE
LOWS WITH MSLP OF 985 AND 972 RESPECTIVELY. THESE SURFACE CYCLONES
WERE A DIRECT RESULT OF UPPER LEVEL POSITIVE VORTICITY ADVECTION IN
THE REGION OF LOW STATIC STABILITY CHARACTERIZED BY THE RELATIVELY
WARM WATERS OF THE PACIFIC. GOING FORWARD...THE SOUTHERN MOST
WAVE...WHICH IS LOCATED ROUGHLY 500MI OUT TO SEA FROM THE CALIFORNIA
SHORELINE...WILL BECOME ORPHANED FROM THE POTENTIAL VORTICITY
RESERVOIR TO THE NORTH...AND GRADUALLY WEAKEN AS IT CROSSES THE
IDAHO ROCKIES AND REACHES THE MIDWEST THURSDAY AFTERNOON. ALTHOUGH
THIS FEATURES IS RATHER BENIGN AT FIRST GLANCE...THERE IS STILL SOME
UPPER LEVEL FORCING FOR ASCENT AS SEEN IN THE QVECT
DIVERGENCE...DRIVEN MAINLY BY THE Q_S VECTORS ON THE DOWNSTREAM SIDE
OF THE TROUGH AXIS...BUT ALSO WITH SOME CONTRIBUTION BY THE Q_N
ACROSS THE TEMPERATURE GRADIENT. THIS UPWARD FORCING WILL BE ENOUGH
TO INDUCE AN EAST SOUTHEASTERLY FLOW AT LOW LEVELS WHICH WILL BECOME
SATURATED AND...ACCORDING TO THE FORECAST SOUNDINGS...LOOKS
INCREASINGLY FAVORABLE FOR SOME FOG AND LIGHT FREEZING DRIZZLE LATE
THURSDAY NIGHT INTO FRIDAY MORNING. THIS IS ALSO SUPPORTED BY LAST
FEW RUNS OF THE SREF FREEZING RAIN PROBABILITIES. THE LIFT IS
WEAK...AND THE SATURATION LAYER IS ONLY A FEW THOUSAND FEET
THICK...SO NOT ANTICIPATING MUCH MORE THAN A FEW HUNDREDTHS OF TOTAL
QPF...BUT ENOUGH TO SLICKEN UP THE UNTREATED PAVED SURFACES FOR THE
FRIDAY MORNING COMMUTE.
SATURDAY THROUGH WEDNESDAY...ONCE THIS WAVE MOVES EASTWARD THE UPPER
LEVEL JET WILL BECOME MORE ZONAL WITH EMBEDDED SHORTWAVES EJECTING
OFF FROM THE LOW IN THE GULF OF ALASKA AND PERIODICALLY TRAVERSING
THE REGION LIKELY RESULTING IN NOTHING MORE THAN A FEW MID LEVEL
CLOUDS. SATURDAY SHOWS A BETTER POTENTIAL FOR SOME MEASURABLE
PRECIP...BUT THE THERMAL PROFILE SHOULD BE WARM ENOUGH THAT IT ALL
WILL FALL AS LIQUID. LOOKING AHEAD...AFTER SEVERAL OSCILLATIONS...A
STRIP OF PV WILL SWING ACROSS NEVADA ON SUNDAY AND DEVELOP A LOW
PRESSURE SYSTEM ON THE LEE SIDE OF THE ROCKIES. THE SOUTHERLY FLOW
AHEAD OF THIS WAVE WILL BRING ANOTHER REINFORCEMENT OF WARM AIR
WHICH WILL LAST THROUGH MONDAY. BY MONDAY NIGHT THE 28.00 ECMWF AND
GFS VARY CONSIDERABLY ON THE TRACK OF THE SURFACE LOW. THE GFS TAKES
IT INTO NORTHERN MINNESOTA...AND DRIVES A COLD FRONT THROUGH THE
REGION. IT IS MUCH DEEPER LOW...AND THEREFORE THE COLD ADVECTION IS
STRONGER WHICH IS WHY THE FORECAST SOUNDINGS SHOW LIGHT SNOW AND
30KT WINDS WITH THE POTENTIAL FOR 40KTS GUSTS ON TUESDAY. MEANWHILE
THE ECMWF IS FURTHER NORTH WITH LESS SENSIBLE WEATHER ACROSS THE
UPPER MIDWEST.
&&
.AVIATION.../12Z TAF ISSUANCE/
FOREMOST AVIATION CONCERN THIS ISSUANCE IS THE TIMING OF THE
IMPROVEMENT TO VFR CIGS FROM THE EXTENSIVE MVFR CONDITIONS CURRENTLY BEING
OBSERVED. THE MAJORITY OF THE MODELS ARE HANDLING THE LLVL RH
FIELDS QUITE POORLY...WITH THE EXCEPTION OF THE 28.06Z GFS AND
28.10Z RAP 925MB SOLUTIONS. HAVE FOLLOWED THE 925MB RH PROGS OF
THE GFS/RAP FOR THE TIMING OF LOW CLOUD SCATTERING AND NORTHEAST
SHIFT...WHICH WILL LIKELY NOT OCCUR UNTIL BETWEEN 17Z AND 20Z FOR
MOST SITES. IT WILL HAPPEN A BIT EARLIER AT KRWF...WHICH IS
SITTING ON THE SOUTHWEST PERIPHERY OF THE DECK. AFTER THE LOW
CLOUDS DEPART...CIRRUS CLOUDS WILL OVERSPREAD THE AREA DURING THE
REMAINDER OF TODAY AND TONIGHT. NORTHWEST WINDS WILL BACK TO THE
SOUTHWEST THIS MORNING...AND THEN TO THE SOUTH BY THIS EVE. SPEEDS
WILL INCREASE TO BETWEEN 7 AND 12KTS BY THIS AFTERNOON...AND THEN
DECREASE TO AROUND 5 KTS THIS EVE.
KMSP...AN OVERCAST CIG OF 1600 FT IS EXPECTED TO RISE TO 1800 FT
BY 1630Z...BECOME BKN BY 18Z...AND THEN SCATTERED AROUND 19Z.
AFTER THAT BKN-OVC CIRRUS CLOUDS WILL PREVAIL THROUGH TONIGHT. NORTHWEST
WINDS WILL SHIFT TO 210 DEGREES AROUND OR SHORTLY AFTER 16Z...AND
THEN BECOME SOUTHERLY DURING THE AFTERNOON. SPEEDS GENERALLY AT 4
TO 7 KTS THROUGH THE PERIOD.
/OUTLOOK FOR KMSP/
THU...VFR IN THE MORNING. MVFR OR LOWER CIG AFTERNOON/OVERNIGHT.
MVFR OR LOWER VIS WITH FOG/FZDZ OVERNIGHT. WINDS ENE 10 KTS.
FRI...MVFR OR LOWER CIGS/VSBYS. FOG AND FZDZ POSSIBLE IN THE
MORNING. WINDS E 10 KTS.
SAT...MVFR OR LOWER CIGS/VSBYS POSSIBLE. CHC OF -RA/DZ. WINDS S 10
KTS.
&&
.MPX WATCHES/WARNINGS/ADVISORIES...
MN...NONE.
WI...NONE.
&&
$$
JRB/LS
AREA FORECAST DISCUSSION...UPDATED
NWS BILLINGS MT
929 AM MST WED NOV 28 2012
.SHORT TERM...VALID FOR TDY AND THU...
UPDATE TO ZFP AND WRKAFP. HIGH CLOUD WAS OVER CENTRAL AND EASTERN
PORTIONS OF THE REGION THIS MORNING BASED ON IR SATELLITE IMAGERY.
MODELS WERE NOT HANDLING THIS CLOUD COVER WELL...AND BASED ON THE
SATELLITE LOOP...THE CLOUDS OVER N WY DID NOT LOOK LIKE THEY WERE
MOVING E MUCH AT ALL. AS A RESULT...HAVE LOWERED TEMPERATURES IN
THE KSHR AREA. ALSO INCREASED MORNING SKY COVER CENTRAL AND E.
OVER THE W...DOWNSLOPE FLOW HAD PUSHED TEMPERATURES INTO THE 40S.
WITH LESS CLOUD COVER THERE...HAVE RAISED HIGHS INTO THE LOW TO
MID 50S. WINDS AT KLVM AND THE STILLWATER MINE WERE GUSTY THIS
MORNING...BUT BELOW ADVISORY CRITERIA. SURFACE MAP SUGGESTED PART
OF THIS MAY BE GAP FLOW...BUT GRADIENT DID NOT HAVE AN IDEAL
ORIENTATION. MIXING WAS LIKELY PLAYING A PART IN THE GUSTY WINDS
AS WELL. HAVE INCREASED WIND SPEEDS THROUGH THE MORNING AND LEFT
THE AFTERNOON ALONE AS RAP BUFKIT SHOWED SPEEDS ALOFT DECREASING
THROUGH THE DAY.
NEW WRF BROUGHT A SHORTWAVE AND FRONT THROUGH THE AREA ON THU
WHICH WILL LIKELY BRING ISOLATED SHOWERS TO THE PLAINS. GOOD
MOISTURE FETCH SETS UP INTO THE W ON FRI WHICH WILL BRING THE
LIKELIHOOD OF PRECIPITATION TO THE SW MOUNTAINS. REST OF FORECAST
WAS IN GOOD SHAPE. ARTHUR
.LONG TERM...VALID FOR FRI...SAT...SUN...MON...TUE...
EXTENDED MODELS CONTINUE TO REMAIN IN FAIRLY GOOD AGREEMENT
THROUGH THE EXTENDED TIMEFRAME. INHERITED FORECAST REMAINS IN
PRETTY GOOD SHAPE BUT DID MAKE A FEW ADJUSTMENTS WITH THIS
FORECAST ISSUANCE. MILD AND WINDY PERIODS WILL PREVAIL FRIDAY INTO
SUNDAY WITH MAINLY A FAST ZONAL FLOW ALOFT WITH A SERIES OF
DISTURBANCES WITHIN THE FLOW MOVING ACROSS OUR FORECAST AREA. LEE-
SIDE TROUGHING WILL DOMINATE FOR THE MOST PART RESULTING IN
PERIODS OF WINDY CONDITIONS FOR THE LIVINGSTON AND ADJACENT
FOOTHILLS LOCATIONS. THIS DOWNSLOPE FLOW ACROSS THE PLAINS WILL
KEEP SHOWER CHANCES VERY LIMITED IF AT ALL WITH THE BEST CHANCES
FOR PRECIP BEING SNOW SHOWERS FOR THE MOUNTAINS...ESPECIALLY THE
WEST FACING SLOPES OF THE BEARTOOTH/ABSAROKA RANGES WHICH COULD
SEE ABOUT 2-4 INCHES OF SNOW EVERY 12 HOURS OR SO FRIDAY AND
SATURDAY.
BY SUNDAY NIGHT INTO MONDAY...A STRONG DISTURBANCE AND TROUGH
SWEEP ACROSS THE NORTHERN ROCKIES. MODELS BRING A STRONG SURFACE
LOW ACROSS OUR FORECAST AREA ALLOWING FOR THE BULK OF PRECIP TO BE
TO OUR NORTHWEST ACROSS NORTH CENTRAL MONTANA. AS THE LOW MOVES
EAST IT WILL ALLOW FOR GUSTY WEST AND NORTHWEST WINDS FOR MOST OF
THE PLAINS. GIVEN THIS DOWNSLOPE FLOW...WILL JUST KEEP A SLIGHT
CHANCE FOR SHOWERS FOR MOST OF THE PLAINS. HOWEVER...DID RAISE
POPS ACROSS OUR FAR NORTHWEST AND WEST ZONES AS THIS AREA IS CLOSE
TO THE HEAVIER PRECIP. IF THE SURFACE LOW SHIFTS FURTHER NORTH OUR
AREA WILL REMAIN MAINLY DRY BUT IF THE LOW SHIFTS FURTHER SOUTH A
MORE SIGNIFICANT PRECIP EVENT WOULD BE LIKELY. TEMPERATURES WITH
THIS SYSTEM ARE NOT THAT COLD AT ALL SO PRECIP WOULD BE A
RAIN/SNOW MIX OR WET SNOW MOST LIKELY. WILL NEED TO MONITOR THIS
OVER THE NEXT COUPLE OF DAYS. HOOLEY
&&
.AVIATION...
MID AND HIGH LEVEL CLOUDS WILL RESULT IN A PARTLY TO MOSTLY
CLOUDY DAY ACROSS THE FORECAST AREA WITH VFR CONDITIONS
PREVAILING. GUSTY SOUTHWEST WINDS WILL BE LIKELY FOR THE KLVM AREA
AND THE BEARTOOTH/ABSAROKA FOOTHILLS THROUGHOUT THE DAY.
HOOLEY/STC
&&
.PRELIMINARY POINT TEMP/POPS...
TDY THU FRI SAT SUN MON TUE
-------------------------------------------------------
BIL 051 029/051 032/055 033/055 037/055 038/046 032/044
0/B 02/W 00/B 11/B 12/W 22/W 11/B
LVM 054 031/051 040/052 037/055 038/055 037/042 028/040
0/N 22/W 12/W 22/W 23/W 43/W 21/B
HDN 051 024/046 025/051 029/054 031/056 034/048 029/046
0/B 02/J 00/B 11/B 11/B 22/W 11/B
MLS 042 017/041 025/050 029/052 031/053 034/043 026/040
0/B 02/J 00/B 11/B 11/B 22/W 11/B
4BQ 047 019/045 025/051 027/054 031/056 034/049 029/045
0/B 01/B 00/B 10/B 00/B 22/W 11/B
BHK 046 015/036 023/046 029/048 031/052 032/041 024/035
0/B 01/B 00/B 10/B 00/B 12/W 11/B
SHR 039 016/044 026/054 029/055 031/056 035/046 026/044
0/B 01/B 00/B 21/B 01/B 23/W 11/B
&&
.BYZ WATCHES/WARNINGS/ADVISORIES...
MT...NONE.
WY...NONE.
&&
$$
WEATHER.GOV/BILLINGS
AREA FORECAST DISCUSSION...UPDATED
NWS NORTH PLATTE NE
500 PM CST THU NOV 29 2012
.UPDATE...
.AVIATION...
VFR IS EXPECTED ALL AREAS OVERNIGHT THROUGH FRIDAY.
AN ARCTIC FRONT ACROSS CNTL SD THIS EVENING WILL DROP SOUTH AND
INTO NCNTL NEB OVERNIGHT. THE FRONT IS NOT EXPECTED TO PRODUCE ANY FLIGHT
LIMITATIONS AT THIS TIME. THE RAP MODEL...ETAL SUGGEST STRATUS
WILL FROM ALONG AND NORTH OF THE MISSOURI RIVER...EAST OF THE FCST
AREA.
OTHERWISE SCT-BKN HIGH LEVEL CLOUDINESS WILL CONTINUE THROUGH
FRIDAY.
&&
.PREV DISCUSSION... /ISSUED 305 PM CST THU NOV 29 2012/
SYNOPSIS...
12Z H5 HAND ANALYSIS FROM THIS MORNING WAS INDICATING BROAD ZONAL
FLOW EXTENDING ACROSS THE CONUS. LOW PRESSURE WAS PRESENT ACROSS
NORTH CENTRAL CANADA...NRN QUEBEC...AND OFF THE COAST OF BRITISH
COLUMBIA. FURTHER SOUTH ACROSS THE CONUS...STRONG MID AND UPPER
LEVEL FLOW...HAS SPREAD ABUNDANT MID AND HIGH LEVEL CLOUDINESS
ACROSS THE WESTERN THIRD OF THE CONUS TDY. SCATTERED TO BROKEN UPPER
LEVEL CLOUDINESS WHICH WAS PRESENT ACROSS CENTRAL AND NORTHERN
NEBRASKA EARLIER THIS MORNING...AND HAS SHIFTED EAST BY MIDDAY.
UNDER SUNNY SKIES...TEMPERATURES AS OF 2 PM CST...RANGED FROM 46 AT
AINSWORTH...TO 70 AT IMPERIAL.
DISCUSSION...
SHORT RANGE...TONIGHT THROUGH SUNDAY NIGHT...FORECASTING CHALLENGE
WILL BE TEMPERATURES AND THE IMPACT OF CLOUD COVER AND SNOW COVER ON
THEM.
FOR TONIGHT...A WEAK DISTURBANCE WILL TRACK ACROSS THE
DAKOTAS...BACKING A WEAK COOL FRONT INTO NORTHERN NEBRASKA TONIGHT.
THE SRN SURGE OF THE FRONT IS EXPECTED TO REACH THE CENTRAL FORECAST
AREA OVERNIGHT...LIFTING NORTH AS A WARM FRONT ON FRIDAY. LOWS
TONIGHT WILL BE COOLEST IN THE PLATTE RIVER VALLEY WITH LIGHT
WESTERLY WINDS...AND ACROSS THE SNOWFIELD IN THE NRN CWA...WHICH
WILL ENCOMPASS NORTHERN SHERIDAN...AND A LARGE PORTION OF CHERRY
COUNTY.
ON FRIDAY...LIGHT SRLY WINDS WILL DEVELOP AS A WARM FRONT LIFTS
NORTHEAST OF THE FORECAST AREA. WARMER H85 AIR WILL PUSH INTO
NORTHERN NEBRASKA FRIDAY AFTERNOON...RESULTING IN HIGHS IN THE
MIDDLE 50S. SIDED WITH THE COOLER MET GUIDANCE...ESPECIALLY OVER
CHERRY AND SHERIDAN COUNTY...WHERE SNOW COVER IS EXPECTED TO PERSIST
AT LEAST THROUGH MIDDAY FRIDAY. ELSEWHERE...HIGHS SHOULD TOP OUT IN
THE UPPER 50S AND LOWER 60S UNDER SUNNY SKIES. HIGH LEVEL CLOUD
COVER WILL BE ON THE INCREASE FRIDAY NIGHT...AS AN UPPER LEVEL JET
STREAK CROSSES THE NORTHERN ROCKIES AND NORTHERN PLAINS. WITH DECENT
AGREEMENT BETWEEN THE GFS AND NAM SOLNS WITH RESPECT TO THE DEGREE
OF UPPER LEVEL MOISTURE...OPTED TO INCREASE CLOUD COVER FRIDAY NIGHT
AND BOOSTED MIN TEMPS ACCORDINGLY WITH MOSTLY CLOUDY SKIES EXPECTED.
SATURDAY AND SUNDAY...SKIES WILL CLEAR SATURDAY MORNING AS THE
BEFORE MENTIONED JET STREAK PUSHES INTO THE UPPER MIDWEST. AT THE
SAME TIME...A SURFACE TROUGH OF LOW PRESSURE WILL TRACK ACROSS THE
DAKOTAS...SHIFTING WINDS TO THE WEST SATURDAY AFTERNOON. THE
COMBINATION OF FULL SUN...WESTERLY WINDS AND H85 TEMPS IN THE LOWER
TEENS C...WILL RESULT IN HIGHS IN THE MID 60S. SOME TEMPS MAY TOP OUT
IN THE LOWER 70S IN THE FAR SOUTHWEST AS H85 TEMPS APPROACH THE
MIDDLE TEENS C. ON SUNDAY...A SURFACE TROUGH OF LOW PRESSURE WILL
DEEPEN ACROSS THE PANHANDLE...SHIFTING WINDS FROM THE WEST TO THE
SOUTH AND INCREASING THEM TO 10 TO 20 MPH SUNDAY AFTERNOON. BASED ON
H85 TEMPS AND DECENT MIXING POTENTIAL...ANOTHER DAY OF HIGHS IN THE
60S LOOKS ON TRACK.
LONG RANGE...MONDAY THROUGH THURSDAY...A TANDEM OF COLD FRONTS WILL
TRACK ACROSS THE REGION NEXT WEEK...THE FIRST ON MONDAY...WHICH WILL
BE PRIMARILY A WIND PRODUCER...AND A SECOND ON WEDNESDAY NIGHT.
HIGHS NEXT WEEK WILL BE COOLER THAN THIS WEEKENDS READINGS...WITH
HIGHS IN THE 50S EXPECTED. ARCTIC AIR MAY BEGIN TO APPROACH THE
NORTHERN PLAINS ON THURSDAY...WITH THE GFS PUSHING AN ARCTIC FRONT
THROUGH WRN AND NORTH CENTRAL NEBRASKA THURSDAY...WHILE THE ECMWF
SOLN DELAYS THIS A COUPLE OF DAYS. DECIDED TO KEEP TEMPS WARM AND
DELAY ANY POTENTIAL ARCTIC FROPA TIL AFTER DAY 7 BASED ON THE SLOWER
ECMWF SOLN. DRY CONDS WILL CONTINUE INTO THE EXTENDED AS WELL.
AVIATION...
FOR THE 18Z TAF ISSUANCE...VISUAL FLIGHT RULES THROUGH MIDDAY FRIDAY
OVER WESTERN AND NORTH CENTRAL NEBRASKA WITH PASSING HIGH CLOUDS AOA
20K FT MOVING IN THE WESTERLIES OVER THE AREA. GENERALLY WESTERLY
FLOW WOULD BE EXPECTED AT THE SURFACE FOR AREA TERMINALS...WHICH
SHOULD REMAIN AOB 12KTS THROUGH AFTERNOON...THEN GOING LIGHT AND
VARIABLE THEREAFTER. ONE EXCEPTION BEING ACROSS THE FAR WESTERN
SANDHILLS...WHERE WIND GUSTS TO 20KTS OR HIGHER WILL CONTINUE.
RECENT METARS OVER THE WESTERN PANHANDLE REGION ACTUALLY INDICATE
MUCH STRONGER WIND SPEEDS...WHICH NEAR TERM MODEL GUIDANCE HINTS AT
SOME OF THIS MOMENTUM SPREADING EAST...TO POSSIBLY A KOGA TO KIEN
LINE....WHICH SEEMS PLAUSIBLE. REGARDLESS...WIND SPEEDS WOULD
DECREASE SHORTLY AFTER SUNDOWN.
FIRE WEATHER...
NEAR CRITICAL FIRE WEATHER CONDITIONS TO CONTINUE THROUGH LATE
AFTERNOON TODAY ACROSS SOUTHWEST NEBRASKA AND THE SOUTHEASTERN
PANHANDLE...WITH SIMILAR CONDITIONS EXPECTED OVER THE SAME AREA
TOMORROW. ABNORMALLY WARM...DRY AIRMASS HAS SETTLED ACROSS THE
REGION...WITH SURFACE RELATIVE HUMIDITY FALLING BELOW 15 PERCENT
OVER MUCH OF FIRE ZONE 210...AND OVER SOUTHERN PORTIONS OF 204.
EXPECTING THIS TREND TO CONTINUE THROUGH LATE AFTERNOON TODAY...WITH
SOME LOCATIONS POSSIBLY RECORDING MINIMUM RH OF LESS THAN 10 PERCENT
/MAINLY SOUTH OF INTERSTATE 80/. AFTER SUNDOWN...RH VALUES WILL
INCREASE STEADILY WITH THE COOLING TEMPERATURES. FOR TOMORROW...A
WEAK FRONTAL BOUNDARY WILL ALLOW FOR SLIGHTLY COOLER
TEMPERATURES...BUT WITH THE DRY AIRMASS...RH WILL ONCE AGAIN FALL TO
20 PERCENT OR LESS. ELSEWHERE...RESIDUAL MOISTURE FROM SNOWFALL
LAST WEEK WILL HELP KEEP MINIMUM RH VALUES AT OR ABOVE 25 PERCENT.
NOW ONTO THE WIND COMPONENT...A CRAIG HIGH HAS DEVELOPED /FAVORABLE
PATTERN FOR GUSTY WESTERLY WIND OVER THE PANHANDLE REGION/...WIND
GUSTS TO 25 MPH MAY BE POSSIBLE ACROSS THE FAR EASTERN PANHANDLE
THROUGH LATE AFTERNOON TODAY...BUT THE STRONGEST WIND SPEEDS WILL
REMAIN FURTHER WEST /WESTERN AND CENTRAL PANHANDLE INTO WYOMING/.
BREEZY WIND SPEEDS CAN BE EXPECTED ONCE AGAIN FOR FRIDAY...BUT AGAIN
THE STRONGER WIND GUSTS /ALBEIT 25 MPH OR LESS/ WILL BE OUT OVER THE
EASTERN PANHANDLE...WITH LIGHTER WIND SPEEDS /15 MPH OR LESS/ FOR ALL
OTHER AREAS.
GIVEN THE MARGINALITY OF THE FIRE WEATHER CONDITIONS...NO FIRE
HEADLINES ARE ANTICIPATED TODAY OR TOMORROW...BUT LOCALIZED RFW
CONDITIONS MAY EXIST FOR AN HOUR OR TWO LATE THIS AFTERNOON AND
POSSIBLY LATE TOMORROW FOR PORTIONS OF FIRE ZONE 204 AND 210.
&&
.LBF WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
SHORT TERM/EXTENDED...CDC
AVIATION...CDC
AREA FORECAST DISCUSSION
NWS RALEIGH NC
120 PM EST WED NOV 28 2012
.SYNOPSIS...
COOL HIGH PRESSURE WILL BUILD OVER THE AREA TODAY THROUGH FRIDAY...
THEN SHIFT OFFSHORE OVER THE WEEKEND.
&&
.NEAR TERM /THROUGH THURSDAY NIGHT/...
AS OF 1020 AM WEDNESDAY...
THROUGH TONIGHT:
MORNING SOUNDINGS SHOW DECENT MOISTURE BELOW 850MB...ENOUGH THAT A
FEW STRATOCU WERE LOCATED OVER THE PIEDMONT MAINLY ALONG AND NORTH
OF U.S. 64...AND ESPECIALLY JUST NORTH OF THE VIRGINIA BORDER.
SOUNDINGS SHOWED THE MOISTURE WAS DEEPER AS ONE PROGRESSED EAST...
AND THE LATEST NAM...WHILE MAYBE TOO AGGRESSIVE WITH THE DEPICTION
OF THE AMOUNT OF LOW-LEVEL MOISTURE...CAPTURED THE PATTERN PRETTY
WELL. BOTH THE NAM AND THE RAP ADVECT DRIER AIR AT 850MB AND 925MB
DURING THE DAY SUCH THAT BY 18Z...AND MOST CERTAINLY 21Z...THE DEW
POINT DEPRESSION IN THE LOW LEVELS BECOMES HIGH AS NOTED ON MODEL
SOUNDINGS. SUNNY TO MOSTLY SUNNY CONDITIONS ARE EXPECTED OVERALL...
WITH A FEW INSTANCES OF PARTLY SUNNY CONDITIONS POSSIBLE TOWARD THE
LAKES OF THE NORTHEAST PIEDMONT AND NORTHERN COASTAL PLAIN MAINLY
LATE THIS MORNING THROUGH EARLY AFTERNOON. TEMPERATURE RECOVERY HAS
BEEN DECENT TO START THE DAY...AND KEPT TEMPERATURES AS PREVIOUSLY
FORECAST OR MAYBE NUDGED UP A DEGREE...IN CONCERT WITH 1000-850MB
THICKNESSES AND A BLEND OF MOS GUIDANCE. THE SURFACE GRADIENT IS
SLACK BUT WITH MIXING THERE COULD BE A GUST OR TWO IN THE LOWER
TEENS KNOTS...BUT GENERALLY WINDS 5 TO 10 MPH FOR THE AFTERNOON.
WITH IDEAL RADIATIONAL COOLING CONDITIONS TONIGHT...EXPECT CHILLY
OVERNIGHT LOWS OF 25 TO 30.
THURSDAY AND THURSDAY NIGHT:
DRY QUITE CONDITIONS WILL CONTINUE AS UPPER AIR PATTERN REALLY
FLATTENS OUT ON THURSDAY WITH POLAR WESTERLIES RETREATING NORTHWARD
NEAR THE US/CANADA BORDER. SURFACE HIGH PRESSURE CENTERED OVER THE
AREA WILL MODERATE SLOWLY AS IT SHIFTS OFF THE CAROLINA COAST BY
FRIDAY MORNING. OTHER THAN SOME THIN HIGH LEVEL MOISTURE SKIRTING
ACROSS THE AREA IN THE ZONAL FLOW ALOFT...IT WILL REMAIN
SUNNY/MOSTLY CLEAR THROUGH THE PERIOD. HIGHS IN THE LOWER 50S
NORTH/NORTHEAST TO MID/UPPER 50S SOUTH. OVERNIGHT LOWS IN THE
MID/UPPER 20S ACROSS NORTH AND OUTLYING OR RURAL AREAS TO LOWER
30S ELSEWHERE.
&&
.SHORT TERM /FRIDAY THROUGH SATURDAY NIGHT/...
AS OF 120 PM WEDNESDAY...
FOR FRIDAY/FRIDAY NIGHT: THE WEAKENING SURFACE HIGH SHIFTS NORTHEAST
OFF THE NC COAST ON FRIDAY AND MERGES INTO A STRONG POLAR HIGH
CENTERED OVER SRN QUEBEC... ALTHOUGH THE CORE OF THE COLDER AIR
HOLDS WELL TO OUR NORTH OVER THE NORTHEAST STATES... AND THE
CHARACTER OF THE AIR MASS OVER NC WILL CHANGE LITTLE. THE SURFACE
RIDGE WILL CONTINUE TO EXTEND THROUGH CENTRAL NC... AND WHILE THE
LOW LEVEL EASTERLY ONSHORE-DIRECTED FLOW WILL INCREASE OVER THE
SOUTHEAST COAST... THE RIDGE ORIENTATION WILL HOLD MUCH OF THIS
ATLANTIC INFLOW TO OUR SOUTH. HOWEVER... THE LIGHT WINDS AND GRADUAL
INCREASE IN SURFACE DEW POINTS MAY BRING ABOUT PATCHY FOG/STRATUS
LATE FRIDAY NIGHT MAINLY OVER THE SRN AND WRN CWA WHERE THE
NAM/GFS/ECMWF DEPICT WEAK LOW LEVEL MOIST ISENTROPIC UPGLIDE.
ALOFT... THE WEAK NEGATIVELY TILTED TROUGH LOCATED OVER NRN MEXICO
THIS MORNING WILL MERGE WITH A FASTER WAVE TO THE NORTH MOVING ONTO
THE WEST COAST... AND THE RESULTANT SHORTWAVE TROUGH WILL TRACK
QUICKLY ACROSS THE OHIO VALLEY AND GREAT LAKES FRIDAY... MOVING OFF
THE NORTHEAST COAST FRIDAY NIGHT. EXCEPT FOR THE NEAR-SURFACE
LAYER... MOISTURE THROUGH THE COLUMN REMAINS QUITE LOW... ALTHOUGH
FORECAST SOUNDINGS DO SUPPORT HIGH THIN CLOUDS LATE FRIDAY INTO
FRIDAY NIGHT. OTHERWISE... EXPECT PLENTY OF SUNSHINE. EXPECT
SLIGHTLY ABOVE NORMAL HIGHS NEAR 60 TO THE LOWER 60S. LOWS 34-38...
A DEGREE OR SO UNDER STATISTICAL GUIDANCE.
FOR SATURDAY/SATURDAY NIGHT: THE MID LEVEL SHORTWAVE IS EXPECTED TO
MOVE EAST OFF THE NORTHEAST/MIDATLANTIC COAST IN THE MORNING... AND
WILL BE FOLLOWED BY RISING HEIGHTS ALOFT OVER OUR AREA THROUGH
SATURDAY NIGHT. THE SURFACE HIGH STARTS THE DAY CENTERED OVER MAINE
AND MOVES EASTWARD TO OFF THE CANADIAN MARITIME COAST DURING THIS
TIME... WHILE STILL EXTENDING THROUGH NC. EXPECT A STEADY
MODIFICATION IN THE LOW LEVEL AIR MASS TO A MILDER AND MORE MOIST
ENVIRONMENT AS SURFACE DEW POINTS CONTINUE TO RISE WITH THE LIGHT
PERSISTENT EASTERLY FLOW. EXPECT SCATTERED TO BROKEN FLAT CUMULUS AS
THE LOW LEVEL MOISTURE MIXES TO THE BASE OF THE SUBSIDENCE INVERSION
ALOFT... BUT OTHERWISE SKIES SHOULD BE MOSTLY SUNNY. WE SHOULD SEE
ANOTHER ROUND OF PATCHY FOG/STRATUS LATE SATURDAY NIGHT AREAWIDE
WITH THE CONTINUED RISE IN LOW LEVEL MOISTURE... CAPPED BY NET
WARMING IN THE 900-800 MB LAYER... WITH LITTLE TO NO SURFACE WIND.
THE RISE IN LOW LEVEL THICKNESSES SUPPORTS HIGHS A BIT WARMER THAN
FRIDAY... 61-66. MILD LOWS OF 39-45. -GIH
&&
.LONG TERM /SUNDAY THROUGH TUESDAY/...
AS OF 240 AM WEDNESDAY...
MODELS SHOW A SHORTWAVE TROUGH APPROACHING THE REGION FROM THE WEST
ON SUNDAY/SUNDAY NIGHT. HOWEVER...MODELS HAVE CONTINUED THEIR TREND
OF SHOWING THE BEST ENERGY TRACKING NORTH OF THE REGION...WHICH
WOULD RESULT IN A DRY FORECAST FOR CENTRAL NC. ONCE THE SHORTWAVE
TROUGH MOVES OFFSHORE LATE SUNDAY INTO MONDAY...MODELS INDICATE AN
MID/UPPER LEVEL RIDGE WILL BUILD EAST INTO THE AREA FOR EARLY NEXT
WEEK...MAINTAINING THE FAIR WEATHER CONDITIONS ACROSS CENTRAL NC.
TEMPS WILL CONTINUE TO MODERATE THROUGH THE PERIOD. EVEN WITH
INCREASED CLOUD COVER EXPECTED ON SUNDAY (ASSOCIATED WITH THE
AFOREMENTIONED SHORT WAVE TROUGH)...HIGH TEMPS ARE EXPECTED TO BE
ABOVE NORMAL...GENERALLY IN THE LOW/MID 60S. AS MID/UPPER LEVEL
RIDGING BUILDS ACROSS THE AREA...CLOUD COVER WILL DECREASE AND
HEIGHTS WILL INCREASE EVEN MORE...ALLOWING HIGH TEMPS TO RISE INTO
THE MID/UPPER 60S (MAYBE EVEN APPROACHING 70 DEGREES) BY THE
BEGINNING OF NEXT WEEK. OVERNIGHT LOWS WILL REMAIN IN THE 40S. CLOUD
COVER WILL BEGIN TO INCREASE LATE TUESDAY AS A MORE AMPLIFIED TROUGH
AND ASSOCIATED COLD FRONT IS PROGGED TO APPROACH THE REGION FROM THE
WEST AT THE VERY TAIL END OF THE CURRENT FORECAST PERIOD.
&&
.AVIATION /18Z WEDNESDAY THROUGH MONDAY/...
AS OF 1155 AM WEDNESDAY...
VFR CONDITIONS WILL PERSIST THROUGH THE 18Z VALID TAF PERIOD. WINDS
AT THE SURFACE SHOULD BE LIGHT...AND EVEN THROUGH 2000FT WINDS
SHOULD ONLY INCREASE TO AROUND 10KT. A VARIABLE WIND WAS FORECAST
FROM TONIGHT THROUGH THURSDAY MORNING AS THE ACTUAL LOCATION OF THE
CENTER OF THE HIGH WILL DETERMINE THE DIRECTION. IT IS LIKELY THAT
TOWARD THE END OF THE 18Z VALID TAF PERIOD THE TRIAD SITES WILL
BECOME PREDOMINANTLY SOUTHWEST...AND AT KFAY THERE COULD BE A
TENDENCY FOR MOST HOURS TO SHOW SOME NORTHEAST WIND COMPONENT. SREF
GUIDANCE SHOWS THAT THE CHANCES FOR MVFR CONDITIONS IN FOG ARE LOW.
BEYOND THE 18Z VALID TAF PERIOD...VFR CONDITIONS SHOULD CONTINUE TO
DOMINATE OVERALL. WINDS AT THE SURFACE AND ALOFT SHOULD BECOME
BROADLY SOUTHWEST...GRADUALLY INCREASING MOISTURE OVER THE REGION.
WITH THE INCREASE IN LOW-LEVEL MOISTURE...THERE WILL BE AN INCREASE
IN PROBABILITIES FOR MAINLY MVFR FOG EARLY SUNDAY AND MONDAY
MORNINGS.
&&
.RAH WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...HARTFIELD
NEAR TERM...DJF/CBL
SHORT TERM...HARTFIELD
LONG TERM...KRR
AVIATION...DJF
AREA FORECAST DISCUSSION
NWS RALEIGH NC
1155 AM EST WED NOV 28 2012
.SYNOPSIS...
COOL HIGH PRESSURE WILL BUILD OVER THE AREA TODAY THROUGH FRIDAY...
THEN SHIFT OFFSHORE OVER THE WEEKEND.
&&
.NEAR TERM /THROUGH THURSDAY NIGHT/...
AS OF 1020 AM WEDNESDAY...
THROUGH TONIGHT:
MORNING SOUNDINGS SHOW DECENT MOISTURE BELOW 850MB...ENOUGH THAT A
FEW STRATOCU WERE LOCATED OVER THE PIEDMONT MAINLY ALONG AND NORTH
OF U.S. 64...AND ESPECIALLY JUST NORTH OF THE VIRGINIA BORDER.
SOUNDINGS SHOWED THE MOISTURE WAS DEEPER AS ONE PROGRESSED EAST...
AND THE LATEST NAM...WHILE MAYBE TOO AGGRESSIVE WITH THE DEPICTION
OF THE AMOUNT OF LOW-LEVEL MOISTURE...CAPTURED THE PATTERN PRETTY
WELL. BOTH THE NAM AND THE RAP ADVECT DRIER AIR AT 850MB AND 925MB
DURING THE DAY SUCH THAT BY 18Z...AND MOST CERTAINLY 21Z...THE DEW
POINT DEPRESSION IN THE LOW LEVELS BECOMES HIGH AS NOTED ON MODEL
SOUNDINGS. SUNNY TO MOSTLY SUNNY CONDITIONS ARE EXPECTED OVERALL...
WITH A FEW INSTANCES OF PARTLY SUNNY CONDITIONS POSSIBLE TOWARD THE
LAKES OF THE NORTHEAST PIEDMONT AND NORTHERN COASTAL PLAIN MAINLY
LATE THIS MORNING THROUGH EARLY AFTERNOON. TEMPERATURE RECOVERY HAS
BEEN DECENT TO START THE DAY...AND KEPT TEMPERATURES AS PREVIOUSLY
FORECAST OR MAYBE NUDGED UP A DEGREE...IN CONCERT WITH 1000-850MB
THICKNESSES AND A BLEND OF MOS GUIDANCE. THE SURFACE GRADIENT IS
SLACK BUT WITH MIXING THERE COULD BE A GUST OR TWO IN THE LOWER
TEENS KNOTS...BUT GENERALLY WINDS 5 TO 10 MPH FOR THE AFTERNOON.
WITH IDEAL RADIATIONAL COOLING CONDITIONS TONIGHT...EXPECT CHILLY
OVERNIGHT LOWS OF 25 TO 30.
THURSDAY AND THURSDAY NIGHT:
DRY QUITE CONDITIONS WILL CONTINUE AS UPPER AIR PATTERN REALLY
FLATTENS OUT ON THURSDAY WITH POLAR WESTERLIES RETREATING NORTHWARD
NEAR THE US/CANADA BORDER. SURFACE HIGH PRESSURE CENTERED OVER THE
AREA WILL MODERATE SLOWLY AS IT SHIFTS OFF THE CAROLINA COAST BY
FRIDAY MORNING. OTHER THAN SOME THIN HIGH LEVEL MOISTURE SKIRTING
ACROSS THE AREA IN THE ZONAL FLOW ALOFT...IT WILL REMAIN
SUNNY/MOSTLY CLEAR THROUGH THE PERIOD. HIGHS IN THE LOWER 50S
NORTH/NORTHEAST TO MID/UPPER 50S SOUTH. OVERNIGHT LOWS IN THE
MID/UPPER 20S ACROSS NORTH AND OUTLYING OR RURAL AREAS TO LOWER
30S ELSEWHERE.
&&
.SHORT TERM /FRIDAY THROUGH SATURDAY NIGHT/...
AS OF 230 AM WEDNESDAY...
THE WEATHER IS EXPECTED TO REMAIN QUIET THROUGH THE SHORT TERM
PERIOD AS IT CONTINUES TO BE DOMINATED BY HIGH PRESSURE. TEMPS WILL
GRADUALLY MODERATE THROUGH SATURDAY AS THE CENTER OF THE SURFACE
HIGH WILL BEGIN TO SLIP OFFSHORE ON FRIDAY (RESULTING IN SOUTHERLY
FLOW RETURNING TO THE REGION) AND SHORTWAVE RIDGING BRIEFLY BUILDS
OVER THE AREA (MOST PRONOUNCED ON SATURDAY). HIGHS ARE EXPECTED TO
BE IN THE UPPER 50S TO LOW/MID 60S (WARMEST SATURDAY)...WITH
OVERNIGHT LOWS GENERALLY IN THE MID 30S ON FRIDAY NIGHT BEFORE
WARMING INTO THE LOWER 40S BY SATURDAY NIGHT. THERE COULD BE SOME
INCREASING HIGH CLOUDS (ESPECIALLY ON SATURDAY) AHEAD OF SOME SHORT
WAVE ENERGY APPROACHING FROM THE WEST.
&&
.LONG TERM /SUNDAY THROUGH TUESDAY/...
AS OF 240 AM WEDNESDAY...
MODELS SHOW A SHORTWAVE TROUGH APPROACHING THE REGION FROM THE WEST
ON SUNDAY/SUNDAY NIGHT. HOWEVER...MODELS HAVE CONTINUED THEIR TREND
OF SHOWING THE BEST ENERGY TRACKING NORTH OF THE REGION...WHICH
WOULD RESULT IN A DRY FORECAST FOR CENTRAL NC. ONCE THE SHORTWAVE
TROUGH MOVES OFFSHORE LATE SUNDAY INTO MONDAY...MODELS INDICATE AN
MID/UPPER LEVEL RIDGE WILL BUILD EAST INTO THE AREA FOR EARLY NEXT
WEEK...MAINTAINING THE FAIR WEATHER CONDITIONS ACROSS CENTRAL NC.
TEMPS WILL CONTINUE TO MODERATE THROUGH THE PERIOD. EVEN WITH
INCREASED CLOUD COVER EXPECTED ON SUNDAY (ASSOCIATED WITH THE
AFOREMENTIONED SHORT WAVE TROUGH)...HIGH TEMPS ARE EXPECTED TO BE
ABOVE NORMAL...GENERALLY IN THE LOW/MID 60S. AS MID/UPPER LEVEL
RIDGING BUILDS ACROSS THE AREA...CLOUD COVER WILL DECREASE AND
HEIGHTS WILL INCREASE EVEN MORE...ALLOWING HIGH TEMPS TO RISE INTO
THE MID/UPPER 60S (MAYBE EVEN APPROACHING 70 DEGREES) BY THE
BEGINNING OF NEXT WEEK. OVERNIGHT LOWS WILL REMAIN IN THE 40S. CLOUD
COVER WILL BEGIN TO INCREASE LATE TUESDAY AS A MORE AMPLIFIED TROUGH
AND ASSOCIATED COLD FRONT IS PROGGED TO APPROACH THE REGION FROM THE
WEST AT THE VERY TAIL END OF THE CURRENT FORECAST PERIOD.
&&
.AVIATION /18Z WEDNESDAY THROUGH MONDAY/...
AS OF 1155 AM WEDNESDAY...
VFR CONDITIONS WILL PERSIST THROUGH THE 18Z VALID TAF PERIOD. WINDS
AT THE SURFACE SHOULD BE LIGHT...AND EVEN THROUGH 2000FT WINDS
SHOULD ONLY INCREASE TO AROUND 10KT. A VARIABLE WIND WAS FORECAST
FROM TONIGHT THROUGH THURSDAY MORNING AS THE ACTUAL LOCATION OF THE
CENTER OF THE HIGH WILL DETERMINE THE DIRECTION. IT IS LIKELY THAT
TOWARD THE END OF THE 18Z VALID TAF PERIOD THE TRIAD SITES WILL
BECOME PREDOMINANTLY SOUTHWEST...AND AT KFAY THERE COULD BE A
TENDENCY FOR MOST HOURS TO SHOW SOME NORTHEAST WIND COMPONENT. SREF
GUIDANCE SHOWS THAT THE CHANCES FOR MVFR CONDITIONS IN FOG ARE LOW.
BEYOND THE 18Z VALID TAF PERIOD...VFR CONDITIONS SHOULD CONTINUE TO
DOMINATE OVERALL. WINDS AT THE SURFACE AND ALOFT SHOULD BECOME
BROADLY SOUTHWEST...GRADUALLY INCREASING MOISTURE OVER THE REGION.
WITH THE INCREASE IN LOW-LEVEL MOISTURE...THERE WILL BE AN INCREASE
IN PROBABILITIES FOR MAINLY MVFR FOG EARLY SUNDAY AND MONDAY
MORNINGS.
&&
.RAH WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...GIH
NEAR TERM...DJF/CBL
SHORT TERM...KRR
LONG TERM...KRR
AVIATION...DJF
AREA FORECAST DISCUSSION
NWS RALEIGH NC
1020 AM EST WED NOV 28 2012
.SYNOPSIS...
COOL HIGH PRESSURE WILL BUILD OVER THE AREA TODAY THROUGH FRIDAY...
THEN SHIFT OFFSHORE OVER THE WEEKEND.
&&
.NEAR TERM /THROUGH THURSDAY NIGHT/...
AS OF 1020 AM WEDNESDAY...
THROUGH TONIGHT:
MORNING SOUNDINGS SHOW DECENT MOISTURE BELOW 850MB...ENOUGH THAT A
FEW STRATOCU WERE LOCATED OVER THE PIEDMONT MAINLY ALONG AND NORTH
OF U.S. 64...AND ESPECIALLY JUST NORTH OF THE VIRGINIA BORDER.
SOUNDINGS SHOWED THE MOISTURE WAS DEEPER AS ONE PROGRESSED EAST...
AND THE LATEST NAM...WHILE MAYBE TOO AGGRESSIVE WITH THE DEPICTION
OF THE AMOUNT OF LOW-LEVEL MOISTURE...CAPTURED THE PATTERN PRETTY
WELL. BOTH THE NAM AND THE RAP ADVECT DRIER AIR AT 850MB AND 925MB
DURING THE DAY SUCH THAT BY 18Z...AND MOST CERTAINLY 21Z...THE DEW
POINT DEPRESSION IN THE LOW LEVELS BECOMES HIGH AS NOTED ON MODEL
SOUNDINGS. SUNNY TO MOSTLY SUNNY CONDITIONS ARE EXPECTED OVERALL...
WITH A FEW INSTANCES OF PARTLY SUNNY CONDITIONS POSSIBLE TOWARD THE
LAKES OF THE NORTHEAST PIEDMONT AND NORTHERN COASTAL PLAIN MAINLY
LATE THIS MORNING THROUGH EARLY AFTERNOON. TEMPERATURE RECOVERY HAS
BEEN DECENT TO START THE DAY...AND KEPT TEMPERATURES AS PREVIOUSLY
FORECAST OR MAYBE NUDGED UP A DEGREE...IN CONCERT WITH 1000-850MB
THICKNESSES AND A BLEND OF MOS GUIDANCE. THE SURFACE GRADIENT IS
SLACK BUT WITH MIXING THERE COULD BE A GUST OR TWO IN THE LOWER
TEENS KNOTS...BUT GENERALLY WINDS 5 TO 10 MPH FOR THE AFTERNOON.
WITH IDEAL RADIATIONAL COOLING CONDITIONS TONIGHT...EXPECT CHILLY
OVERNIGHT LOWS OF 25 TO 30.
THURSDAY AND THURSDAY NIGHT:
DRY QUITE CONDITIONS WILL CONTINUE AS UPPER AIR PATTERN REALLY
FLATTENS OUT ON THURSDAY WITH POLAR WESTERLIES RETREATING NORTHWARD
NEAR THE US/CANADA BORDER. SURFACE HIGH PRESSURE CENTERED OVER THE
AREA WILL MODERATE SLOWLY AS IT SHIFTS OFF THE CAROLINA COAST BY
FRIDAY MORNING. OTHER THAN SOME THIN HIGH LEVEL MOISTURE SKIRTING
ACROSS THE AREA IN THE ZONAL FLOW ALOFT...IT WILL REMAIN
SUNNY/MOSTLY CLEAR THROUGH THE PERIOD. HIGHS IN THE LOWER 50S
NORTH/NORTHEAST TO MID/UPPER 50S SOUTH. OVERNIGHT LOWS IN THE
MID/UPPER 20S ACROSS NORTH AND OUTLYING OR RURAL AREAS TO LOWER
30S ELSEWHERE.
&&
.SHORT TERM /FRIDAY THROUGH SATURDAY NIGHT/...
AS OF 230 AM WEDNESDAY...
THE WEATHER IS EXPECTED TO REMAIN QUIET THROUGH THE SHORT TERM
PERIOD AS IT CONTINUES TO BE DOMINATED BY HIGH PRESSURE. TEMPS WILL
GRADUALLY MODERATE THROUGH SATURDAY AS THE CENTER OF THE SURFACE
HIGH WILL BEGIN TO SLIP OFFSHORE ON FRIDAY (RESULTING IN SOUTHERLY
FLOW RETURNING TO THE REGION) AND SHORTWAVE RIDGING BRIEFLY BUILDS
OVER THE AREA (MOST PRONOUNCED ON SATURDAY). HIGHS ARE EXPECTED TO
BE IN THE UPPER 50S TO LOW/MID 60S (WARMEST SATURDAY)...WITH
OVERNIGHT LOWS GENERALLY IN THE MID 30S ON FRIDAY NIGHT BEFORE
WARMING INTO THE LOWER 40S BY SATURDAY NIGHT. THERE COULD BE SOME
INCREASING HIGH CLOUDS (ESPECIALLY ON SATURDAY) AHEAD OF SOME SHORT
WAVE ENERGY APPROACHING FROM THE WEST.
&&
.LONG TERM /SUNDAY THROUGH TUESDAY/...
AS OF 240 AM WEDNESDAY...
MODELS SHOW A SHORTWAVE TROUGH APPROACHING THE REGION FROM THE WEST
ON SUNDAY/SUNDAY NIGHT. HOWEVER...MODELS HAVE CONTINUED THEIR TREND
OF SHOWING THE BEST ENERGY TRACKING NORTH OF THE REGION...WHICH
WOULD RESULT IN A DRY FORECAST FOR CENTRAL NC. ONCE THE SHORTWAVE
TROUGH MOVES OFFSHORE LATE SUNDAY INTO MONDAY...MODELS INDICATE AN
MID/UPPER LEVEL RIDGE WILL BUILD EAST INTO THE AREA FOR EARLY NEXT
WEEK...MAINTAINING THE FAIR WEATHER CONDITIONS ACROSS CENTRAL NC.
TEMPS WILL CONTINUE TO MODERATE THROUGH THE PERIOD. EVEN WITH
INCREASED CLOUD COVER EXPECTED ON SUNDAY (ASSOCIATED WITH THE
AFOREMENTIONED SHORT WAVE TROUGH)...HIGH TEMPS ARE EXPECTED TO BE
ABOVE NORMAL...GENERALLY IN THE LOW/MID 60S. AS MID/UPPER LEVEL
RIDGING BUILDS ACROSS THE AREA...CLOUD COVER WILL DECREASE AND
HEIGHTS WILL INCREASE EVEN MORE...ALLOWING HIGH TEMPS TO RISE INTO
THE MID/UPPER 60S (MAYBE EVEN APPROACHING 70 DEGREES) BY THE
BEGINNING OF NEXT WEEK. OVERNIGHT LOWS WILL REMAIN IN THE 40S. CLOUD
COVER WILL BEGIN TO INCREASE LATE TUESDAY AS A MORE AMPLIFIED TROUGH
AND ASSOCIATED COLD FRONT IS PROGGED TO APPROACH THE REGION FROM THE
WEST AT THE VERY TAIL END OF THE CURRENT FORECAST PERIOD.
&&
.AVIATION /15Z WEDNESDAY THROUGH SUNDAY/...
AS OF 1020 AM WEDNESDAY...
VFR CONDITIONS WILL DOMINATE AS SURFACE HIGH PRESSURE SETTLES OVER
THE AREA. SURFACE WINDS WILL VEER FROM NORTHERLY THIS MORNING TO
NWLY THIS AFTERNOON...WITH WINDS BECOMING CALM TONIGHT.
SEASONABLY MILD HIGH PRESSURE WILL DOMINATE THE WEATHER PATTERN
THROUGH THE WEEKEND...WITH VFR CONDITIONS THROUGH SUNDAY.
&&
.RAH WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...GIH
NEAR TERM...DJF/CBL
SHORT TERM...KRR
LONG TERM...KRR
AVIATION...DJF/CBL
AREA FORECAST DISCUSSION
NWS BISMARCK ND
636 PM CST THU NOV 29 2012
.DISCUSSION...SATELLITE LOOPS SHOW A CIRCULATION CENTER IN CLOUDS
BETWEEN BISMARCK AND ABERDEEN. THIS SHOWS UP ON THE RUC AS A
VORTICITY CENTER. LOCAL RADARS HAVE SUFFICIENT RETURNS TO ADD A
SLIGHT CHANCE FOR FREEZING RAIN AND SLEET IN THE JAMES RIVER VALLEY.
PROBABILITY IS LOW AT THIS TIME...JUST 20 PERCENT CHANCE. THIS IS
THE MAIN CHANGE THIS UPDATE.
&&
.AVIATION...AT 6 PM CST...A WARM FRONT EXTENDED ACROSS EASTERN
MONTANA INTO NORTHEAST WYOMING. THE WARM FRONT WILL MOVE INTO
WESTERN NORTH DAKOTA FRIDAY AFTERNOON. MVFR CONDITIONS FROM KMOT-
KBIS-KJMS THROUGH 16Z...IMPROVING TO VFR AFTER 16Z. IFR CONDITIONS
ACROSS THE SOUTHWEST...KDIK...THROUGH 03-05Z...IMPROVING TO MVFR
AFTER 05Z...THEN VFR AFTER 06Z. VFR AT KISN.
&&
.BIS WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...WAA
AVIATION...WAA
AREA FORECAST DISCUSSION
NWS MORRISTOWN TN
315 AM EST WED NOV 28 2012
.SHORT TERM (TODAY AND TONIGHT)...TYPICAL SCENARIO FOR THE FORECAST
AREA WITH A FRONTAL SYSTEM WELL SOUTHEAST OF THE REGION WITH
NORTHERLY FLOW ALOFT AND LOW CLOUDS TRAPPED UNDER AN INVERSION
AROUND 925 MB. APPEARS THE FORECAST HINGES ON THE THINNING CLOUD
LAYER (ALREADY SEEING THE HIGH TERRAIN ALONG THE NORTH CAROLINA
BORDER PEAKING THROUGH THE STRATUS). SEEMS LIKE THE RUC13 HAS THE
BEST HANDLE ON THE SITUATION WITH LAYER HANGING IN THERE A WHILE
LONGER THAN OTHER MODELS INDICATE...ALTHOUGH THE GFS ISN`T AS BAD AS
THE WRF PROGNOSTICATION ABILITIES. IT`S ALWAYS INTERESTING BECAUSE
WHEN THIS ASPECT IS INCORRECT...TEMPERATURES ARE WAY OFF. THE MODELS
HAD WHAT LITTLE HEAT THE AREA PICKED UP ON TUESDAY HAPPILY RADIATING
AWAY UNDER CLEARING OVERNIGHT SKIES. MODEL SUGGESTIONS INDICATE
TEMPS SHOULD BE SEVERAL DEGREES COOLER TOWARD DAYBREAK ALONG WITH
SOME SATURATED SURFACE CONDITIONS IN SPOTS. WENT AHEAD AND STAYED
WITH A PESSIMISTIC CLEARING TREND CLOSE TO THE RUC13 IDEA WITH
SOUTHEAST TENNESSEE AND SOUTHWEST NORTH CAROLINA CLEARING EARLY IN
THE DAY WITH CLOUDS HANGING AROUND LONGER ACROSS SOUTHWEST VIRGINIA
AND NORTHEAST TENNESSEE. BECAUSE TEMPERATURES LOOK LIKE THEY WILL
START OUT WARMER THAN THEY WERE SUPPOSED TO...STAYED CLOSE TO THE
MOS MAX TEMP BLEND. WOULD EXPECT HIGH PRESSURE AND DRIER AIR TO TAKE
OVER FOR TONIGHT ALLOWING RADIATION AND LOW TEMPERATURES MAINLY IN
THE 20S.
.LONG TERM (THURSDAY THROUGH TUESDAY)...THURSDAY THROUGH SATURDAY
WILL FEATURE A LOW LEVEL RIDGE OFF THE GA/SC COAST...WITH A NEARLY
ZONAL FLOW ALOFT. THIS WILL KEEP THE AREA DRY AND MILD EACH DAY. A
WEAK MIDLEVEL SHORTWAVE TROUGH PASSES TO OUR NORTH ON SUNDAY/SUNDAY
NIGHT. SLIGHT CHANCE POPS IN NORTHERN SECTIONS LOOKS QUITE GENEROUS
AS MOISTURE IS VERY LIMITED...BUT WILL BE KEPT IN THE FORECAST. THE
MID-UPPER LEVEL FLOW AMPLIFIES ON MONDAY AS A DEEP TROUGH MOVES INTO
THE PLAINS. WITH A DEEP SW FLOW...TEMPS WILL RISE WELL ABOVE NORMAL
FOR MONDAY. MODELS ARE IN GOOD AGREEMENT WITH TIMING OF PRECIP WITH
THE ASSOCIATED COLD FRONT...AND WILL ADD CHANCE POPS FOR TUESDAY.
&&
.PRELIMINARY POINT TEMPS/POPS...
CHATTANOOGA AIRPORT, TN 53 30 60 34 62 / 0 0 0 0 0
KNOXVILLE MCGHEE TYSON AIRPORT, TN 50 28 57 32 60 / 0 0 0 0 0
OAK RIDGE, TN 50 28 57 32 60 / 0 0 0 0 0
TRI CITIES AIRPORT, TN 47 23 55 28 59 / 0 0 0 0 0
&&
.MRX WATCHES/WARNINGS/ADVISORIES...
NC...NONE.
TN...NONE.
VA...NONE.
&&
$$
20/DGS
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
1142 AM CST WED NOV 28 2012
.SHORT TERM...THROUGH FRIDAY NIGHT
329 AM CST WED NOV 28 2012
IMMEDIATE FORECAST CONCERN WILL BE CLOUD TREND TODAY...THEN
PRECIPITATION CHANCES THURSDAY NIGHT INTO FRIDAY.
WATER VAPOR IMAGERY/RAP ANALYSIS SHOWS POLAR VORTEX OVER THE
NORTHWEST TERRITORIES WITH A DEEP TROUGH DUG SOUTHWARD INTO THE
GREAT LAKES AND EASTERN SEABOARD. THIS HAS BROUGHT AN OVERALL COLDER
INFLUX OF AIR INTO THE REGION THE PAST SEVERAL DAY. EMBEDDED WITHIN
THIS LONG WAVE TROUGH WAS A MID-LEVEL TROUGH CURRENT MAKING ITS WAY
TOWARD LAKE MICHIGAN. AT THE SURFACE...A COLD FRONT EXTENDED FROM
THE EASTERN U.P. THEN THROUGH NORTHEAST TO SOUTHWEST WI. A SECONDARY
COLD FRONT THEN EXTENDED ACROSS SOUTHERN LAKE SUPERIOR INTO NORTHERN
MN. 11-3.9MICRON IR IMAGERY/SURFACE OBS SHOWING AN EXTENSIVE MASS
OF STRATOCUMULUS WITH THIS FRONT AND WAS MOVING SOUTHEAST TOWARD THE
AREA AT 20-25KT. RAP 0.5KM RH FIELD...WHICH SEEMS TO BE HANDLING
THIS CLOUD MASS THE BEST...KEEPS MOVING THE CLOUD MASS SOUTHWARD TO
ALONG I-90 BY 15Z...THEN STARTS SHIFTING IT BACK TO THE
NORTHEAST/ERODING IN TIME BY AFTERNOON. THIS IS IN RESPONSE TO
INCREASING SOUTHWEST FLOW ON THE BACK SIDE OF A RIDGE OF HIGH
PRESSURE MAKING ITS WAY EAST ACROSS THE AREA AND MIXING THROUGH
925MB PER THE BUFKIT SOUNDING. OTHERWISE...WITH MIXING TROUGH 925MB
TODAY WHERE TEMPERATURES WILL INCREASE TO -3 TO +1C RANGE BY LATER
THIS AFTERNOON...ALONG WITH INCREASING SUNSHINE...LOOK FOR HIGHS IN
THE 25-35 DEGREE RANGE NORTHEAST OF I-94...AND THE 35-40 DEGREE
RANGE SOUTHWEST OF I-94.
PAST TODAY...NEXT CONCERN WILL BE FREEZING DRIZZLE POTENTIAL THURSDAY
NIGHT INTO FRIDAY MORNING. MODELS IN GOOD AGREEMENT IN BRINGING A
WEAK COLD FRONT INTO THE REGION ON THURSDAY THEN STALLING IT OUT
ACROSS NORTHERN IA THROUGH NORTHERN IL THURSDAY NIGHT INTO FRIDAY
MORNING. NAM/GFS SHOW A WEAK MID-LEVEL WAVE MOVING OUT OF THE
NORTHERN/CENTRAL PLAINS AND ALONG THIS BAROCLINIC ZONE THURSDAY NIGHT. THIS
PRODUCES UPWARD VERTICAL MOTION ALONG WITH WEAK LOW-LEVEL MOISTURE
TRANSPORT ACROSS THIS BOUNDARY. NAM AND ESPECIALLY THE GFS BUFKIT
SOUNDINGS SHOW THE LOWEST 5-6KM OF THE COLUMN BECOMING SATURATED
WITH A LACK OF ICE. THIS HAS BEEN A CONSISTENT SIGNAL FOR THE LAST
COUPLE OF DAYS NOW. LOWER BOUNDARY LAYER COOLING/DEEP STRATUS DECK
WITH WEAK OMEGA SHOULD LEAD TO PATCHY FREEZING DRIZZLE AFTER
MIDNIGHT LASTING INTO FRIDAY MORNING. BASED ON THIS INCREASINGLY
CONSISTENT SIGNAL AND THE FACT THAT THE SLIGHTEST AMOUNT OF ICING
CREATES PROBLEMS...WILL HAVE TO MONITOR CLOSELY FOR HEADLINE
POTENTIAL.
MID-LEVEL RIDGING THEN TAKES PLACE BY FRIDAY AFTERNOON FOR AN END TO
THE PRECIPITATION CHANCES. HOWEVER...BUFKIT SOUNDINGS AS WELL AS THE
NAM/GFS LOW-LEVEL RH FIELDS SHOWING STRATUS HOLDING ACROSS THE AREA
UNDER THE SUBSIDENCE INVERSION. THIS IS EXPECTED TO HOLD
TEMPERATURES DOWN SOME...BUT STILL REMAINING SLIGHTLY ABOVE NORMAL
IN THE MIDDLE 30S TO LOWER 40S. STRATUS LOOKS TO HANG ON RIGHT
THROUGH FRIDAY NIGHT WITH LOWS IN THE 30S.
.LONG TERM...SATURDAY THROUGH TUESDAY
329 AM CST WED NOV 28 2012
28.00Z GFS AND ECMWF IN EXCELLENT AGREEMENT IN BRINGING A LOW
PRESSURE SYSTEM OUT OF THE NORTHERN ROCKIES AND INTO THE AREA IN THE
SATURDAY/SATURDAY NIGHT TIME FRAME. GFS SHOWS AMPLE 850MB MOISTURE
TRANSPORT INTO THE AREA AS SOUTHERLY FLOW INCREASES INTO THE AREA
AHEAD OF THE WAVE. HAVE BUMPED POPS INTO THE 30-40 PERCENT RANGE FOR
NOW...BUT MAY HAVE TO BE PUSHED INTO THE LIKELY RANGE IF THIS SIGNAL
REMAINS CONSISTENT. OTHERWISE...LOOKS MILD SATURDAY WITH HIGHS
PUSHING INTO THE MID 40S/LOWER 50S WITH INCREASINGLY MILD SOUTHERLY
SURFACE FLOW. SUNDAY LOOKS TO BE DRY AND UNSEASONABLY MILD WITH
MID-UPPER LEVEL RIDGING TAKING PLACE OVER THE CENTRAL CONUS. HIGHS
ARE EXPECTED TO TOP OFF IN THE MID 40S ACROSS NORTHERN WI/MN...TO
THE MID 50S ACROSS NORTHEAST IA/SOUTHEAST MN/SOUTHWEST WI. MONDAY
WILL SEE A VERY DYNAMIC MID-LEVEL TROUGH/SURFACE LOW EJECT NORTHEAST
OUT OF THE INTERMOUNTAIN WEST AND INTO NORTHERN MN. THIS WILL PUSH A
COLD FRONT TOWARD THE AREA FOR A CHANCE OF RAIN. WILL ALSO HAVE TO
WATCH FOR THE POSSIBILITY OF THUNDER IF ENOUGH INSTABILITY IS
REALIZED. OTHERWISE...THE GFS WAS SHOWING 850MB TEMPERATURES AHEAD
OF THE FRONT AT +2 STANDARD DEVIATIONS CENTERED OVER WI.
HOWEVER...LOOKS LIKE PLENTY OF STRATUS MAY INHIBIT FULL HEATING
POTENTIAL. WITH THIS IN MIND...HIGHS IN THE 50-60 DEGREE RANGE SEEMS
REASONABLE...WHICH WOULD STILL BE SOME 20 DEGREES ABOVE NORMAL. RAIN
CHANCES WILL CONTINUE INTO MONDAY NIGHT AS THE FRONT MAKES PASSAGE
THROUGH THE AREA. RELATIVELY COLDER AND BREEZY CONDITIONS LOOK TO BE
ON TAP FOR TUESDAY IN THE WAKE OF THE DEEP LOW MOVING UP INTO
ONTARIO.
&&
.AVIATION...THROUGH 18Z THURSDAY
1142 AM CST WED NOV 28 2012
MORNING IFR CLOUDS ARE BEGINNING TO ERODE AS SURFACE WINDS TURN
TO THE SOUTHWEST ALONG WITH 925 MB WARMING...HELPING TO MIX OUT
THE SHALLOW CLOUD LAYER. THIS PROCESS WILL TAKE ANOTHER HOUR AT
KLSE...AS A PATCH OF CLOUDS REMAINS NEAR THE TERMINAL. THE
CLEARING WILL GIVE WAY TO VFR CONDITIONS FOR THE REMAINDER OF THE
PERIOD...WITH THE PREDOMINANT FLOW OUT OF THE SOUTH/SOUTHWEST.
SCATTERED TO BROKEN CIRRUS IS EXPECTED TO MOVE OVER THE REGION
THIS AFTERNOON THROUGH THE OVERNIGHT...THEN EXIT EAST BY EARLY
THURSDAY MORNING. SOME FORECAST MODELS SUGGEST AS THESE CLOUDS
EXIT AND ALONG WITH LIGHT SURFACE WINDS...SOME PATCHY FOG IS
POSSIBLE BEGINNING 10Z THROUGH 15Z. THIS CONCERN IS MORE FOR
KRST...AND FOR NOW HAVE INCLUDED A MENTION OF LIGHT FOG/MIST BUT
NO RESTRICTIONS.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
329 AM CST WED NOV 28 2012
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
SHORT TERM...DAS
LONG TERM...DAS
AVIATION...ZT
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
533 AM CST WED NOV 28 2012
.SHORT TERM...THROUGH FRIDAY NIGHT
329 AM CST WED NOV 28 2012
IMMEDIATE FORECAST CONCERN WILL BE CLOUD TREND TODAY...THEN
PRECIPITATION CHANCES THURSDAY NIGHT INTO FRIDAY.
WATER VAPOR IMAGERY/RAP ANALYSIS SHOWS POLAR VORTEX OVER THE
NORTHWEST TERRITORIES WITH A DEEP TROUGH DUG SOUTHWARD INTO THE
GREAT LAKES AND EASTERN SEABOARD. THIS HAS BROUGHT AN OVERALL COLDER
INFLUX OF AIR INTO THE REGION THE PAST SEVERAL DAY. EMBEDDED WITHIN
THIS LONG WAVE TROUGH WAS A MID-LEVEL TROUGH CURRENT MAKING ITS WAY
TOWARD LAKE MICHIGAN. AT THE SURFACE...A COLD FRONT EXTENDED FROM
THE EASTERN U.P. THEN THROUGH NORTHEAST TO SOUTHWEST WI. A SECONDARY
COLD FRONT THEN EXTENDED ACROSS SOUTHERN LAKE SUPERIOR INTO NORTHERN
MN. 11-3.9MICRON IR IMAGERY/SURFACE OBS SHOWING AN EXTENSIVE MASS
OF STRATOCUMULUS WITH THIS FRONT AND WAS MOVING SOUTHEAST TOWARD THE
AREA AT 20-25KT. RAP 0.5KM RH FIELD...WHICH SEEMS TO BE HANDLING
THIS CLOUD MASS THE BEST...KEEPS MOVING THE CLOUD MASS SOUTHWARD TO
ALONG I-90 BY 15Z...THEN STARTS SHIFTING IT BACK TO THE
NORTHEAST/ERODING IN TIME BY AFTERNOON. THIS IS IN RESPONSE TO
INCREASING SOUTHWEST FLOW ON THE BACK SIDE OF A RIDGE OF HIGH
PRESSURE MAKING ITS WAY EAST ACROSS THE AREA AND MIXING THROUGH
925MB PER THE BUFKIT SOUNDING. OTHERWISE...WITH MIXING TROUGH 925MB
TODAY WHERE TEMPERATURES WILL INCREASE TO -3 TO +1C RANGE BY LATER
THIS AFTERNOON...ALONG WITH INCREASING SUNSHINE...LOOK FOR HIGHS IN
THE 25-35 DEGREE RANGE NORTHEAST OF I-94...AND THE 35-40 DEGREE
RANGE SOUTHWEST OF I-94.
PAST TODAY...NEXT CONCERN WILL BE FREEZING DRIZZLE POTENTIAL THURSDAY
NIGHT INTO FRIDAY MORNING. MODELS IN GOOD AGREEMENT IN BRINGING A
WEAK COLD FRONT INTO THE REGION ON THURSDAY THEN STALLING IT OUT
ACROSS NORTHERN IA THROUGH NORTHERN IL THURSDAY NIGHT INTO FRIDAY
MORNING. NAM/GFS SHOW A WEAK MID-LEVEL WAVE MOVING OUT OF THE
NORTHERN/CENTRAL PLAINS AND ALONG THIS BAROCLINIC ZONE THURSDAY NIGHT. THIS
PRODUCES UPWARD VERTICAL MOTION ALONG WITH WEAK LOW-LEVEL MOISTURE
TRANSPORT ACROSS THIS BOUNDARY. NAM AND ESPECIALLY THE GFS BUFKIT
SOUNDINGS SHOW THE LOWEST 5-6KM OF THE COLUMN BECOMING SATURATED
WITH A LACK OF ICE. THIS HAS BEEN A CONSISTENT SIGNAL FOR THE LAST
COUPLE OF DAYS NOW. LOWER BOUNDARY LAYER COOLING/DEEP STRATUS DECK
WITH WEAK OMEGA SHOULD LEAD TO PATCHY FREEZING DRIZZLE AFTER
MIDNIGHT LASTING INTO FRIDAY MORNING. BASED ON THIS INCREASINGLY
CONSISTENT SIGNAL AND THE FACT THAT THE SLIGHTEST AMOUNT OF ICING
CREATES PROBLEMS...WILL HAVE TO MONITOR CLOSELY FOR HEADLINE
POTENTIAL.
MID-LEVEL RIDGING THEN TAKES PLACE BY FRIDAY AFTERNOON FOR AN END TO
THE PRECIPITATION CHANCES. HOWEVER...BUFKIT SOUNDINGS AS WELL AS THE
NAM/GFS LOW-LEVEL RH FIELDS SHOWING STRATUS HOLDING ACROSS THE AREA
UNDER THE SUBSIDENCE INVERSION. THIS IS EXPECTED TO HOLD
TEMPERATURES DOWN SOME...BUT STILL REMAINING SLIGHTLY ABOVE NORMAL
IN THE MIDDLE 30S TO LOWER 40S. STRATUS LOOKS TO HANG ON RIGHT
THROUGH FRIDAY NIGHT WITH LOWS IN THE 30S.
.LONG TERM...SATURDAY THROUGH TUESDAY
329 AM CST WED NOV 28 2012
28.00Z GFS AND ECMWF IN EXCELLENT AGREEMENT IN BRINGING A LOW
PRESSURE SYSTEM OUT OF THE NORTHERN ROCKIES AND INTO THE AREA IN THE
SATURDAY/SATURDAY NIGHT TIME FRAME. GFS SHOWS AMPLE 850MB MOISTURE
TRANSPORT INTO THE AREA AS SOUTHERLY FLOW INCREASES INTO THE AREA
AHEAD OF THE WAVE. HAVE BUMPED POPS INTO THE 30-40 PERCENT RANGE FOR
NOW...BUT MAY HAVE TO BE PUSHED INTO THE LIKELY RANGE IF THIS SIGNAL
REMAINS CONSISTENT. OTHERWISE...LOOKS MILD SATURDAY WITH HIGHS
PUSHING INTO THE MID 40S/LOWER 50S WITH INCREASINGLY MILD SOUTHERLY
SURFACE FLOW. SUNDAY LOOKS TO BE DRY AND UNSEASONABLY MILD WITH
MID-UPPER LEVEL RIDGING TAKING PLACE OVER THE CENTRAL CONUS. HIGHS
ARE EXPECTED TO TOP OFF IN THE MID 40S ACROSS NORTHERN WI/MN...TO
THE MID 50S ACROSS NORTHEAST IA/SOUTHEAST MN/SOUTHWEST WI. MONDAY
WILL SEE A VERY DYNAMIC MID-LEVEL TROUGH/SURFACE LOW EJECT NORTHEAST
OUT OF THE INTERMOUNTAIN WEST AND INTO NORTHERN MN. THIS WILL PUSH A
COLD FRONT TOWARD THE AREA FOR A CHANCE OF RAIN. WILL ALSO HAVE TO
WATCH FOR THE POSSIBILITY OF THUNDER IF ENOUGH INSTABILITY IS
REALIZED. OTHERWISE...THE GFS WAS SHOWING 850MB TEMPERATURES AHEAD
OF THE FRONT AT +2 STANDARD DEVIATIONS CENTERED OVER WI.
HOWEVER...LOOKS LIKE PLENTY OF STRATUS MAY INHIBIT FULL HEATING
POTENTIAL. WITH THIS IN MIND...HIGHS IN THE 50-60 DEGREE RANGE SEEMS
REASONABLE...WHICH WOULD STILL BE SOME 20 DEGREES ABOVE NORMAL. RAIN
CHANCES WILL CONTINUE INTO MONDAY NIGHT AS THE FRONT MAKES PASSAGE
THROUGH THE AREA. RELATIVELY COLDER AND BREEZY CONDITIONS LOOK TO BE
ON TAP FOR TUESDAY IN THE WAKE OF THE DEEP LOW MOVING UP INTO
ONTARIO.
&&
.AVIATION...TODAY AND TONIGHT
533 AM CST WED NOV 28 2012
A LARGE AREA OF STRATUS WAS LOCATED GENERALLY NORTH OF AN AUSTIN
MINNESOTA TO NEILLSVILLE WISCONSIN LINE AT 11Z. SATELLITE TRENDS
SHOW THE WESTERN AREAS OVER SOUTHEAST MINNESOTA MOVING SOUTHEAST.
THE STRATUS HAS MOVED INTO KRST WITH IFR CEILINGS. EXPECT THESE
CLOUDS TO SPREAD INTO KLSE AROUND 13Z WITH LOWER MVFR CEILINGS.
28.10Z RAP 0-0.5KM RELATIVE HUMIDITY PROG INDICATED SOUTHERN EDGE
OF THE STRATUS TO MAKE IT NOT MUCH FURTHER SOUTH THAN THE
INTERSTATE 90 CORRIDOR BEFORE BEGINNING TO LIFT NORTHWARD AND
DISSIPATING MID TO LATE MORNING. ONCE THIS OCCURS...EXPECT VFR
CONDITION FOR THE REMAINDER OF THE TAF PERIOD.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
329 AM CST WED NOV 28 2012
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
SHORT TERM...DAS
LONG TERM...DAS
AVIATION...RABERDING
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
329 AM CST WED NOV 28 2012
.SHORT TERM...THROUGH FRIDAY NIGHT
329 AM CST WED NOV 28 2012
IMMEDIATE FORECAST CONCERN WILL BE CLOUD TREND TODAY...THEN
PRECIPITATION CHANCES THURSDAY NIGHT INTO FRIDAY.
WATER VAPOR IMAGERY/RAP ANALYSIS SHOWS POLAR VORTEX OVER THE
NORTHWEST TERRITORIES WITH A DEEP TROUGH DUG SOUTHWARD INTO THE
GREAT LAKES AND EASTERN SEABOARD. THIS HAS BROUGHT AN OVERALL COLDER
INFLUX OF AIR INTO THE REGION THE PAST SEVERAL DAY. EMBEDDED WITHIN
THIS LONG WAVE TROUGH WAS A MID-LEVEL TROUGH CURRENT MAKING ITS WAY
TOWARD LAKE MICHIGAN. AT THE SURFACE...A COLD FRONT EXTENDED FROM
THE EASTERN U.P. THEN THROUGH NORTHEAST TO SOUTHWEST WI. A SECONDARY
COLD FRONT THEN EXTENDED ACROSS SOUTHERN LAKE SUPERIOR INTO NORTHERN
MN. 11-3.9MICRON IR IMAGERY/SURFACE OBS SHOWING AN EXTENSIVE MASS
OF STRATOCUMULUS WITH THIS FRONT AND WAS MOVING SOUTHEAST TOWARD THE
AREA AT 20-25KT. RAP 0.5KM RH FIELD...WHICH SEEMS TO BE HANDLING
THIS CLOUD MASS THE BEST...KEEPS MOVING THE CLOUD MASS SOUTHWARD TO
ALONG I-90 BY 15Z...THEN STARTS SHIFTING IT BACK TO THE
NORTHEAST/ERODING IN TIME BY AFTERNOON. THIS IS IN RESPONSE TO
INCREASING SOUTHWEST FLOW ON THE BACK SIDE OF A RIDGE OF HIGH
PRESSURE MAKING ITS WAY EAST ACROSS THE AREA AND MIXING THROUGH
925MB PER THE BUFKIT SOUNDING. OTHERWISE...WITH MIXING TROUGH 925MB
TODAY WHERE TEMPERATURES WILL INCREASE TO -3 TO +1C RANGE BY LATER
THIS AFTERNOON...ALONG WITH INCREASING SUNSHINE...LOOK FOR HIGHS IN
THE 25-35 DEGREE RANGE NORTHEAST OF I-94...AND THE 35-40 DEGREE
RANGE SOUTHWEST OF I-94.
PAST TODAY...NEXT CONCERN WILL BE FREEZING DRIZZLE POTENTIAL THURSDAY
NIGHT INTO FRIDAY MORNING. MODELS IN GOOD AGREEMENT IN BRINGING A
WEAK COLD FRONT INTO THE REGION ON THURSDAY THEN STALLING IT OUT
ACROSS NORTHERN IA THROUGH NORTHERN IL THURSDAY NIGHT INTO FRIDAY
MORNING. NAM/GFS SHOW A WEAK MID-LEVEL WAVE MOVING OUT OF THE
NORTHERN/CENTRAL PLAINS AND ALONG THIS BAROCLINIC ZONE THURSDAY NIGHT. THIS
PRODUCES UPWARD VERTICAL MOTION ALONG WITH WEAK LOW-LEVEL MOISTURE
TRANSPORT ACROSS THIS BOUNDARY. NAM AND ESPECIALLY THE GFS BUFKIT
SOUNDINGS SHOW THE LOWEST 5-6KM OF THE COLUMN BECOMING SATURATED
WITH A LACK OF ICE. THIS HAS BEEN A CONSISTENT SIGNAL FOR THE LAST
COUPLE OF DAYS NOW. LOWER BOUNDARY LAYER COOLING/DEEP STRATUS DECK
WITH WEAK OMEGA SHOULD LEAD TO PATCHY FREEZING DRIZZLE AFTER
MIDNIGHT LASTING INTO FRIDAY MORNING. BASED ON THIS INCREASINGLY
CONSISTENT SIGNAL AND THE FACT THAT THE SLIGHTEST AMOUNT OF ICING
CREATES PROBLEMS...WILL HAVE TO MONITOR CLOSELY FOR HEADLINE
POTENTIAL.
MID-LEVEL RIDGING THEN TAKES PLACE BY FRIDAY AFTERNOON FOR AN END TO
THE PRECIPITATION CHANCES. HOWEVER...BUFKIT SOUNDINGS AS WELL AS THE
NAM/GFS LOW-LEVEL RH FIELDS SHOWING STRATUS HOLDING ACROSS THE AREA
UNDER THE SUBSIDENCE INVERSION. THIS IS EXPECTED TO HOLD
TEMPERATURES DOWN SOME...BUT STILL REMAINING SLIGHTLY ABOVE NORMAL
IN THE MIDDLE 30S TO LOWER 40S. STRATUS LOOKS TO HANG ON RIGHT
THROUGH FRIDAY NIGHT WITH LOWS IN THE 30S.
.LONG TERM...SATURDAY THROUGH TUESDAY
329 AM CST WED NOV 28 2012
28.00Z GFS AND ECMWF IN EXCELLENT AGREEMENT IN BRINGING A LOW
PRESSURE SYSTEM OUT OF THE NORTHERN ROCKIES AND INTO THE AREA IN THE
SATURDAY/SATURDAY NIGHT TIME FRAME. GFS SHOWS AMPLE 850MB MOISTURE
TRANSPORT INTO THE AREA AS SOUTHERLY FLOW INCREASES INTO THE AREA
AHEAD OF THE WAVE. HAVE BUMPED POPS INTO THE 30-40 PERCENT RANGE FOR
NOW...BUT MAY HAVE TO BE PUSHED INTO THE LIKELY RANGE IF THIS SIGNAL
REMAINS CONSISTENT. OTHERWISE...LOOKS MILD SATURDAY WITH HIGHS
PUSHING INTO THE MID 40S/LOWER 50S WITH INCREASINGLY MILD SOUTHERLY
SURFACE FLOW. SUNDAY LOOKS TO BE DRY AND UNSEASONABLY MILD WITH
MID-UPPER LEVEL RIDGING TAKING PLACE OVER THE CENTRAL CONUS. HIGHS
ARE EXPECTED TO TOP OFF IN THE MID 40S ACROSS NORTHERN WI/MN...TO
THE MID 50S ACROSS NORTHEAST IA/SOUTHEAST MN/SOUTHWEST WI. MONDAY
WILL SEE A VERY DYNAMIC MID-LEVEL TROUGH/SURFACE LOW EJECT NORTHEAST
OUT OF THE INTERMOUNTAIN WEST AND INTO NORTHERN MN. THIS WILL PUSH A
COLD FRONT TOWARD THE AREA FOR A CHANCE OF RAIN. WILL ALSO HAVE TO
WATCH FOR THE POSSIBILITY OF THUNDER IF ENOUGH INSTABILITY IS
REALIZED. OTHERWISE...THE GFS WAS SHOWING 850MB TEMPERATURES AHEAD
OF THE FRONT AT +2 STANDARD DEVIATIONS CENTERED OVER WI.
HOWEVER...LOOKS LIKE PLENTY OF STRATUS MAY INHIBIT FULL HEATING
POTENTIAL. WITH THIS IN MIND...HIGHS IN THE 50-60 DEGREE RANGE SEEMS
REASONABLE...WHICH WOULD STILL BE SOME 20 DEGREES ABOVE NORMAL. RAIN
CHANCES WILL CONTINUE INTO MONDAY NIGHT AS THE FRONT MAKES PASSAGE
THROUGH THE AREA. RELATIVELY COLDER AND BREEZY CONDITIONS LOOK TO BE
ON TAP FOR TUESDAY IN THE WAKE OF THE DEEP LOW MOVING UP INTO
ONTARIO.
&&
.AVIATION...THROUGH 06Z THURSDAY
1142 PM CST TUE NOV 27 2012
SKIES HAVE CLEARED OUT FOR THE TIME BEING...BUT IT APPEARS AS
THOUGH A LOW LEVEL STRATUS DECK IS EXPECTED TO MOVE IN OVERNIGHT
TOWARD DAY BREAK. THIS 1-2KFT BKN-OVC DECK CURRENTLY IS MAKING ITS
WAY SOUTH ACROSS CENTRAL MINNESOTA AND NORTHWEST WISCONSIN WITH
THE LEADING EDGE TIMED TO GET INTO KRST AROUND 10-11Z AND KLSE
AROUND 13Z. SOME OF THE FORECAST GUIDANCE SUGGESTS THAT THERE MAY
BE ENOUGH DRY AIR MOVING IN WITH A SURFACE RIDGE...BUT IT APPEARS
THAT THIS SOLUTION MAY BE A BIT OPTIMISTIC. WITH THE CORE OF THE
RIDGE NOT GETTING IN UNTIL MID DAY WEDNESDAY...HAVE OPTED TO GO
WITH A MORE PESSIMISTIC MVFR CEILING FORECAST FOR 1-2KFT FOR
WEDNESDAY MORNING. EXPECT THAT IT WILL BREAK UP BY LATE MORNING
WITH VFR CONDITIONS PREVAILING BEYOND THAT.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
329 AM CST WED NOV 28 2012
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
SHORT TERM...DAS
LONG TERM...DAS
AVIATION...HALBACH
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
1142 PM CST TUE NOV 27 2012
.SHORT TERM...THROUGH FRIDAY
200 PM CST TUE NOV 27 2012
MAIN FORECAST CONCERNS ARE ON PRECIPITATION CHANCES THIS EVENING AS
WELL AS THURSDAY NIGHT INTO FRIDAY.
CURRENTLY AS OF 20Z...WATER VAPOR LOOP AND RAP 500MB HEIGHT ANALYSIS
SHOWED RIDGING FROM THE BRITISH COLUMBIA COAST SOUTHWARD THROUGH THE
WESTERN U.S....WHILE TROUGHING WAS PRESENT FROM SOUTHEAST CANADA
INTO THE GREAT LAKES. IN THE NORTHWEST FLOW BETWEEN THE RIDGE AND
TROUGH...A SHORTWAVE TROUGH WAS NOTED OVER NORTHERN MINNESOTA.
ISENTROPIC LIFT DEPICTED ON THE 285-295K SURFACES AHEAD OF THE
SHORTWAVE HAS RESULTED IN SCATTERED-BROKEN ALTOSTRATUS ACROSS THE
FORECAST AREA. FARTHER NORTH...SNOW HAS BEEN FALLING ACROSS NORTHERN
MINNESOTA INTO NORTHERN WI WHERE THE DPVA AND ISENTROPIC LIFT
FORCING IS STRONGEST...ALONG WITH BETTER LOW LEVEL SATURATION PER
12Z INL SOUNDING. A COLD FRONT REPRESENTING THE SHORTWAVE AT THE
SURFACE EXTENDED FROM NORTHEAST MINNESOTA INTO SOUTHEAST SOUTH
DAKOTA. SOUTHWEST WINDS AHEAD OF THE FRONT HAS HELPED PULL WARMER
AIR INTO THE REGION...NOTED BY 925MB TEMPS THAT HAVE CLIMBED AT MPX
FROM -11C AT 00Z TO -4C AT 12Z PER SOUNDINGS. READINGS HAVE CLIMBED
INTO THE LOW TO MID 30S IN MOST LOCATIONS. BEHIND THE FRONT ACROSS
SOUTH DAKOTA...READINGS ARE NOT THAT MUCH COOLER. HOWEVER...ACROSS
SOUTHERN MANITOBA WHERE HIGH PRESSURE SITS...READINGS ARE IN THE
LOWER TEENS. 925MB TEMPS IN THIS AREA ARE -14 TO -18C PER RAP
ANALYSIS.
TONIGHT AND WEDNESDAY...THE UPPER LEVEL PATTERN IS FORECAST TO
DEAMPLIFY SOME ACROSS THE CONUS...IN RESPONSE TO A PORTION OF EAST
PACIFIC TROUGHING MOVING INTO THE WESTERN U.S.. BY 00Z THURSDAY...
500MB HEIGHTS WILL HAVE RISEN NEARLY 120 METERS OVER THE FORECAST
AREA. SUBSIDENCE ASSOCIATED WITH THESE HEIGHT RISES SHOULD KEEP THE
MAJORITY OF THE NEXT 24 HOURS QUIET. THE ONLY CONCERN IS WITH THE
SHORTWAVE OVER NORTHERN MINNESOTA DROPPING SOUTHEAST THROUGH
NORTHERN WISCONSIN THIS EVENING. THE 280-285K ISENTROPIC LIFT
HELPING TO PRODUCE THE SNOW ACROSS NORTHERN MINNESOTA WILL ACCOMPANY
THE SHORTWAVE SOUTHEASTWARD. RIGHT NOW IT APPEARS THE BULK OF THE
SNOW SHOULD STAY NORTH OF THE FORECAST AREA...PER MODEL CONSENSUS
AND SHORTWAVE TRACK...BUT AM CONCERNED AT LEAST SOME FLURRIES COULD
OCCUR OVER TAYLOR/CLARK. HAVE ADDED THE FLURRIES INTO THE FORECAST.
EVENING SHIFT WILL NEED TO WATCH THE SNOW PROGRESSION. OTHERWISE...
THE COLD FRONT LOOKS TO MOVE THROUGH MUCH OF THE FORECAST AREA BY
09Z. 925MB TEMP PROGS SUGGEST A PORTION OF THAT COLDER AIR IN
SOUTHERN MANITOBA WILL MAKE IT SOUTH INTO THE FORECAST AREA...WITH
TEMPS AT 12Z WEDNESDAY RANGING FROM -2C OVER NORTHEAST IOWA TO -8 TO
-10C IN TAYLOR COUNTY. AS SUCH...THE COLDEST READINGS TONIGHT ARE IN
TAYLOR COUNTY. THE WINDS AND SOME STRATUS CLOUDS BEHIND THE FRONT
SHOULD MITIGATE THE TEMPERATURE FALL SOMEWHAT...THOUGH. THE 925MB
TEMPS HOLD FAIRLY STEADY THROUGH ABOUT 18Z...DUE TO HIGH PRESSURE
SLIDING ACROSS... THEN BEGIN TO CLIMB. MIXING TO THE 925MB TEMPS
RESULTS IN HIGHS IN THE UPPER 20S TO NEAR 40...COLDEST ACROSS TAYLOR
AND CLARK COUNTIES. THIS MIXING SHOULD BE DOABLE DESPITE SOME
INCREASE IN HIGH CLOUDS DEPICTED IN THE AFTERNOON.
WEDNESDAY NIGHT AND THURSDAY...SOME MORE 500MB HEIGHT RISES ARE
FORECAST OVER THE AREA...IN RESPONSE TO THE WESTERN U.S. RIDGE
FLATTENING OUT AND BEING PUSHED EASTWARD BY THE PORTION OF THE EAST
PACIFIC TROUGH HEADING INTO THE DAKOTAS BY 00Z FRIDAY. SUBSIDENCE
AGAIN ASSOCIATED WITH THESE HEIGHT RISES SHOULD BE ENOUGH TO KEEP
THE AREA DRY. THIS SUBSIDENCE DOES LOOK TO CLEAR THE CIRRUS OUT
WEDNESDAY NIGHT. HOWEVER...AN INCREASE IN CIRRUS IS EXPECTED ACROSS
MUCH OF THE AREA ON THURSDAY AS THAT SHORTWAVE TROUGH COMES INTO THE
DAKOTAS. IN ADDITION...A MASS OF LOW CLOUDS IS PROGGED TO COME INTO
NORTHERN PORTIONS OF THE FORECAST AREA THURSDAY AFTERNOON. THESE ARE
IN THE WAKE OF A COLD FRONTAL PASSAGE...FORECAST TO DROP SOUTH
THROUGH THE AREA MOSTLY DURING THE MORNING. 925MB TEMPS CLIMB NICELY
WEDNESDAY NIGHT AHEAD OF THAT FRONT DROPPING SOUTH...TOPPING OUT
BETWEEN 2C AND -2C BY 12Z. THIS WARM ADVECTION COMBINED WITH A
SOUTHERLY BREEZE SHOULD HELP KEEP TEMPERATURES UP. A BLEND OF
GUIDANCE SEEMS REASONABLE FOR LOWS SUGGESTING MAINLY IN THE 20S. FOR
THURSDAY...925MB TEMPS FALL TO 0 TO -4C AT 18Z THURSDAY...THOUGH THE
WARMER NIGHT AND SOME FILTERED SUNSHINE WILL ALLOW TEMPERATURES TO
BE ABOUT 5 DEGREES WARMER THAN WEDNESDAY.
THURSDAY NIGHT AND FRIDAY...THE SHORTWAVE TROUGH ACROSS THE DAKOTAS
MODELS FORECAST TO COME ACROSS THE AREA FRIDAY MORNING. MODELS VARY
ON STRENGTH OF THE TROUGH...WITH THE 27.12Z GFS STRONGEST AND 27.12Z
NAM WEAKEST. HOWEVER...THE STRENGTH OF THE SHORTWAVE APPEARS TO HAVE
LITTLE SENSIBLE IMPACT ON THE WEATHER AS THE MID-LEVELS OF THE
ATMOSPHERE ARE SUGGESTED TO BE QUITE DRY. IN FACT...MUCH OF THE
ACTION LOOKS TO OCCUR BELOW 850MB. THE POST-FRONTAL LOW CLOUD MASS
DROPPING SOUTH THURSDAY AFTERNOON MODELS ARE IN GOOD AGREEMENT IN
HAVING IT ENCOMPASS LOCATIONS FROM I-90 NORTH BY 06Z FRIDAY. THE LOW
CLOUD DECK MAY EVEN DRIFT FARTHER SOUTH BETWEEN 06-12Z TO ENCOMPASS
MOST OF THE AREA. THE REASON THIS IS SO IMPORTANT IS THAT ISENTROPIC
LIFT PLOTS SHOW WEAK LIFT ON THE 280-285K SURFACES THURSDAY NIGHT
INTO FRIDAY MORNING. THE LIFT IN THE LOW CLOUD DECK COULD RESULT IN
SOME LIGHT FREEZING DRIZZLE DEVELOPING. SINCE THIS HAS BEEN A
CONSISTENT SIGNAL...HAVE INCLUDED THE MENTION OF IT IN THE FORECAST.
GIVEN THE IMPACTS FROM JUST A TINY BIT OF FREEZING DRIZZLE...MAY
NEED AN ADVISORY AT SOME POINT. ALSO ADDED A FOG MENTION AREA WIDE
FOR 06-18Z FRIDAY GIVEN THE VERY LOW CEILINGS PROGGED. CLOUDS LOOK
TOUGH TO CLEAR TOO FRIDAY AFTERNOON AS A GENERAL EAST-SOUTHEAST LOW
LEVEL FLOW PERSISTS. THUS...ANTICIPATING MUCH OF THIS 24 HOUR PERIOD
TO BE CLOUDY. THE CLOUDS WILL LIMIT THE DIURNAL FALL AND RISE...AND
IT IS WORTH NOTING THAT 925MB TEMPS CHANGE VERY LITTLE THROUGH
FRIDAY SUGGESTING LITTLE IN THE WAY OF ADVECTION. THUS...
TEMPERATURES SHOULD NOT CHANGE A WHOLE LOT. ONLY HAVE ABOUT A 10
DEGREE CHANGE FROM NIGHT AND DAY IN THE FORECAST.
.LONG TERM...FRIDAY NIGHT THROUGH TUESDAY
200 PM CST TUE NOV 27 2012
VERY GOOD MODEL AGREEMENT EXISTS AND REMAINS AMONGST THE 27.12Z
ECMWF/GFS/UKMET/CANADIAN AND GFS ENSEMBLES THROUGH MUCH OF THE LONG
TERM FORECAST...BOTH AT THE SURFACE AND ALOFT. THE UPPER LEVEL FLOW
THROUGH THE SHORT TERM PERIOD THAT IS TRANSITIONING FROM NORTHWEST
TO ZONAL BECOMES SOUTHWESTERLY FOR THE WEEKEND. THE FLOW THEN
AMPLIFIES AS A PROGRESSIVE DEEP TROUGH MARCHES ACROSS THE WEST AND
CENTRAL U.S. EARLY NEXT WEEK. MAIN PRECIPITATION TIMES OF NOTE ARE
ON SATURDAY INTO SATURDAY EVENING...AS WELL AS MONDAY INTO MONDAY
NIGHT. THE FIRST IS ASSOCIATED WITH A SHORTWAVE TROUGH COMING
THROUGH THE SOUTHWESTERLY FLOW. A SURGE OF GULF OF MEXICO MOISTURE
ACCOMPANIES THE TROUGH AS IT MOVES INTO THE AREA...ENOUGH TO LIKELY
PRODUCE A LOW LEVEL STRATUS DECK AS WELL AS SOME LIGHT
PRECIPITATION. RIGHT NOW MAYBE WE GET UP TO A TENTH OF AN INCH AT
MOST. THE MONDAY INTO MONDAY NIGHT PERIOD IS MORE INTERESTING HAVING
A DYNAMIC DEEP TROUGH COMING ACROSS. 850MB WINDS INCREASE TO 40-50
KT HELPING TO BRING 850MB DEWPOINTS UP TO 8C OR SO. ONE ISSUE IS
THAT THE SATURATION AGAIN IS ALL IN THE LOW LEVELS...AND THE
ATMOSPHERE IS CAPPED...THUS ANOTHER LIGHT RAIN/DRIZZLE EVENT WOULD
OCCUR. OVERALL...THOUGH...CONFIDENCE IN EITHER EVENT PRODUCING
WIDESPREAD QPF IS FAIRLY LOW AT THIS POINT SINCE THE DYNAMICAL
FORCING IS ALL NORTH OF THE AREA. THUS...PRECIPITATION CHANCES ARE
IN THE 20-40 RANGE.
TEMPERATURES ARE MORE INTERESTING HERE IN THE LONG TERM PERIOD.
925MB TEMPS ARE FORECAST BETWEEN 3-7C ON SATURDAY...AS MUCH AS 6-10C
ON SUNDAY PER 27.00Z/12Z ECMWF AND 10-14C BY LATE IN THE DAY MONDAY.
THE INCOMING STRATUS DECK ON BOTH SATURDAY AND MONDAY WILL LIKELY
HOLD BACK THE POTENTIAL FOR MIXING TO 925MB. HOWEVER...ADVECTION
ALONE SHOULD BE ABLE TO PUSH READINGS INTO THE MID 40S TO LOW 50S ON
SATURDAY AND INTO THE 50S EVERYWHERE ON MONDAY PER MODEL CONSENSUS.
SHOULD ANY UNEXPECTED SUNSHINE OCCUR...HIGHS COULD EASILY BE HIGHER.
MONDAYS FORECAST HIGHS ARE ONLY A FEW DEGREES BELOW RECORDS...59 AT
ROCHESTER AND 61 AT LA CROSSE. SUNDAY HAS THE BEST OPPORTUNITY FOR
SUNSHINE...AND IF THE ECMWF IS CORRECT...WE COULD EASILY CLIMB INTO
THE 50S AND PERHAPS REACH 60 IN SOUTHERN AREAS. HAVE BUMPED UP HIGHS
ABOVE THE CONSENSUS TO RANGE FROM THE MID 40S TO MID 50S. IT APPEARS
RECORDS ON SUNDAY SHOULD BE SAFE WITH ROCHESTER AT 62 AND LA CROSSE
AT 64. FOR TUESDAY...DECENT COOLING COMES IN THANKS TO THE UPPER
TROUGH SLIDING INTO THE AREA. FOLLOWED THE CONSENSUS HIGHS IN THE
40S FOR NOW.
&&
.AVIATION...THROUGH 06Z THURSDAY
1142 PM CST TUE NOV 27 2012
SKIES HAVE CLEARED OUT FOR THE TIME BEING...BUT IT APPEARS AS
THOUGH A LOW LEVEL STRATUS DECK IS EXPECTED TO MOVE IN OVERNIGHT
TOWARD DAY BREAK. THIS 1-2KFT BKN-OVC DECK CURRENTLY IS MAKING ITS
WAY SOUTH ACROSS CENTRAL MINNESOTA AND NORTHWEST WISCONSIN WITH
THE LEADING EDGE TIMED TO GET INTO KRST AROUND 10-11Z AND KLSE
AROUND 13Z. SOME OF THE FORECAST GUIDANCE SUGGESTS THAT THERE MAY
BE ENOUGH DRY AIR MOVING IN WITH A SURFACE RIDGE...BUT IT APPEARS
THAT THIS SOLUTION MAY BE A BIT OPTIMISTIC. WITH THE CORE OF THE
RIDGE NOT GETTING IN UNTIL MID DAY WEDNESDAY...HAVE OPTED TO GO
WITH A MORE PESSIMISTIC MVFR CEILING FORECAST FOR 1-2KFT FOR
WEDNESDAY MORNING. EXPECT THAT IT WILL BREAK UP BY LATE MORNING
WITH VFR CONDITIONS PREVAILING BEYOND THAT.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
200 PM CST TUE NOV 27 2012
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
SHORT TERM...AJ
LONG TERM...AJ
AVIATION...HALBACH
AREA FORECAST DISCUSSION
NWS GREEN BAY WI
1038 PM CST TUE NOV 27 2012
UPDATED AVIATION PORTION FOR 06Z TAF ISSUANCE
.SHORT TERM...TONIGHT AND WEDNESDAY.
LATEST RUC ANALYSIS AND SATELLITE/RADAR IMAGERY SHOW A SHORTWAVE
DROPPING SOUTHEAST OVER WESTERN WISCONSIN EARLY THIS AFTERNOON...AND
IS KICKING OFF SNOW SHOWERS OVER THE NW CORNER OF THE STATE. A FEW
SNOW SHOWERS LOOK RATHER BEEFY ON RADAR...AND AN OBSERVATION AT
HAYWARD DROPPED VSBYS DOWN TO A QUARTER MILE BRIEFLY. WILL BE ON
THE LOOK OUT FOR A HISA EVENT THIS AFTERNOON. COLD FRONT IS
TRAILING THE LEAD SHORTWAVE...AND IS POSITIONED FROM THE ARROWHEAD
OF MINNESOTA TO NORTHERN SOUTH DAKOTA. A WIDESPREAD LOW STRATUS
DECK EXISTS IMMEDIATELY BEHIND THIS FRONT...AND A FEW FLURRIES HAVE
BEEN NOTED ON THE OBS THERE TOO. AS SHORTWAVE ACTIVITY AND THE COLD
FRONT CROSS THE REGION TONIGHT...CLOUDS AND PRECIP CHANCES ARE THE
MAIN FORECAST CONCERNS.
TONIGHT...WEAK SHORTWAVE ACTIVITY WILL SWING ACROSS THE REGION
TONIGHT AND PUSH A COLD FRONT ACROSS THE AREA. THOUGH MOISTURE IS
GENERALLY LACKING...MOISTURE IS GREATER TO THE NORTH. RADARS SUGGEST
N-C WISCONSIN WILL SEE LIKELY SNOW SHOWERS THIS EVENING SO WILL
RAISE POPS A BIT. NOT SURE HOW FAR SOUTH TO BRING A MENTION OF
FLURRIES...BUT NORTH OF ROUTE 29 SEEMS LIKE A LOGICAL DIVIDER BASED
ON RADAR TRENDS. BEHIND THE FRONT...A LOW STRATUS DECK HAS BEEN
ADVANCING SOUTHEAST. MODELS SCOUR OUT THE LOW LEVEL MOISTURE
TONIGHT AND SUGGEST THIS STRATUS DECK MAY ONLY REACH N-C WISCONSIN.
GIVEN THE SOLID LOOK TO THE STRATUS AND THE COLD ADVECTION TO TAKE
PLACE...THINK THIS IS TOO OPTIMISTIC AND WILL BRING THE STRATUS DECK
INTO CENTRAL WISCONSIN AS WELL. BY THE TIME IT GETS THERE LATE
TONIGHT...ENOUGH DRY AIR AND DOWNSLOPING SHOULD KEEP THE STRATUS
FROM REACHING NE AND E-C WISCONSIN. NORTHWEST WINDS WILL KEEP SNOW
SHOWERS AND FLURRIES GOING OVER VILAS COUNTY THROUGH THE NIGHT
HOWEVER. A STRONGER PRESSURE GRADIENT SHOULD KEEP THE BL MIXED
ENOUGH TO GO WITH WARMER TEMPS COMPARED TO LAST NIGHT. WILL GO WITH
LOW TEENS NORTH TO NEAR 20 SE.
WEDNESDAY...PRETTY QUIET AS HIGH PRESSURE RIDGE AXIS WORKS ACROSS
THE STATE. BACKING LOW LEVEL WINDS WILL FORCE LAKE CLOUDS TO LIFT
OFF TO THE NORTHEAST AND AWAY FROM N-C WISCONSIN DURING THE
MORNING. IF LOW STRATUS DOES STICK AROUND INTO WEDNESDAY
MORNING...THINK THE INCOMING RIDGE AXIS WILL CAUSE ANY CLOUDS TO
BREAK UP EARLY IN THE PERIOD. MOST OF THE AREA SHOULD SEE MOSTLY
SUNNY CONDITIONS FOR MUCH OF THE DAY. HIGHS RANGING FROM THE MID
20S NORTH TO LOWER 30S SOUTH.
.LONG TERM...WEDNESDAY NIGHT THROUGH NEXT TUESDAY. WINTER IS SLOW
TO ARRIVE THIS YEAR AND THE MEDIUM RANGE MODELS SUGGEST THAT THE
MILD WEATHER PATTERN WILL CONTINUE.
DRY NORTHWEST FLOW IS EXPECTED THROUGH THURSDAY WITH TEMPERATURES
RISING ABOVE NORMAL FOR THIS TIME OF THE YEAR. UPPER FLOW IS
FORECAST TO BECOME ZONAL FRIDAY THROUGH SUNDAY WITH SOME
OVERRUNNING LIGHT SNOW...DRIZZLE OR FREEZING DRIZZLE THURSDAY NIGHT
AND FRIDAY AS A WEAK SHORTWAVE TROUGH MOVES THROUGH THE FLOW.
MOISTURE IS SHALLOW AND NOT VERY ABUNDANT SO DO NOT EXPECT MUCH. A
MORE SIGNIFICANT SHORTWAVE IS EXPECTED SATURDAY AFTERNOON OR
EVENING WHICH SHOULD HAVE A BIT MORE MOISTURE AS WELL.
TEMPERATURES WILL BE WELL ABOVE FREEZING SO WHATEVER FALLS SHOULD
BE RAIN.
UPPER RIDGE REALLY BUILDS MONDAY AND SOUTHERLY LOW LEVEL FLOW
INCREASES TOO. 925MB TEMPERATURES FORECAST TO RISE TO +10C MONDAY
AFTERNOON AND EVENING WHICH COULD HELP DRIVE TEMPERATURES INTO THE
50S IF THERE IS ANY SUNSHINE AT ALL. A COLD FRONT WILL MOVE
THROUGH MONDAY NIGHT AND BRING SLIGHTLY COOLER AIR FOR TUESDAY.
&&
.AVIATION...SCT LAKE-EFFECT SNOW SHOWERS OR FLURRIES WILL LINGER
OVER FAR NORTH CENTRAL WI OVERNIGHT...THEN COME TO AN END BY WEDS
MORNING. MVFR CIGS ARE EXPECTED OVER NORTH CENTRAL AND CENTRAL
WI...ALTHOUGH CLEARING IS EXPECTED THERE TOWARD DAYBREAK. HIGH
PRESSURE WILL BRING VFR CONDITIONS ON WEDNESDAY. SOME LLWS MAY
DEVELOP AT RHI/AUW/CWA ON WEDS EVENING...AS SW WINDS INCREASE
TO 35 KNOTS AT 1000-1500 FT AGL.
KIECKBUSCH
&&
.GRB WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS GAYLORD MI
1145 PM EST THU NOV 29 2012
.SYNOPSIS...
ISSUED AT 406 PM EST THU NOV 29 2012
THE SEASONABLY CHILLY AIR WILL CONTINUE TO HANG ACROSS THE REGION
THROUGH FRIDAY...BRINGING A BIT MORE LIGHT SNOW SHOWERS OR FLURRIES
AT TIMES. PERHAPS EVEN SOME FREEZING DRIZZLE LATER TONIGHT INTO
FRIDAY MORNING. MILDER TEMPERATURES AND RAIN CHANCES...WILL MAKE A
RETURN TO NORTHERN MICHIGAN THIS WEEKEND...AND INTO EARLY NEXT
WEEK...AS A PAIR OF SYSTEMS MOVE OVER THE NORTHERN PLAINS AND PASS
NORTHWEST OF THE STATE.
&&
.UPDATE...
ISSUED AT 1102 PM EST THU NOV 29 2012
EARLIER FCST UPDATE ACTUALLY WORKING OUT RATHER WELL (THAT DOESN`T
ALWAYS HAPPEN HERE!)...AND PER LATEST RADAR/RAP TRENDS...HAVE
DECIDED TO HOIST A WINTER WEATHER ADVISORY BASICALLY FROM M-72 ON
NORTH THROUGH MID MORNING. ALREADY SEEING A NICE COATING OF ICE
HERE AT THE OFFICE AND ACROSS THE HIGHER TERRAIN PER SPOTTER
REPORTS. PER RAP GUIDANCE (WHICH HAD THE BEST HANDLE OF BLOSSOMING
OF PRECIP EARLIER)...BEST LOW LEVEL WARM ADVECTION ASCENT IN THE
925-875MB LAYER WILL OCCUR BASICALLY NORTH OF M-72 OVERNIGHT. THAT
DOESN`T PRECLUDE SOME PATCHY FREEZING DRIZZLE TO THE SOUTH...
ESPECIALLY GIVEN STALLING ARCTIC FRONTAL BOUNDARY DOWN THAT WAY
AND BETTER POOLED MOISTURE...BUT CURRENT ADVISORY AREA IS MY BEST
GUESS WHERE THINGS MAY GET QUITE SLICK BY MORNING. CAN FORESEE A
BIT OF A MIX WITH SOME SNOW AT TIMES LATER TONIGHT AS WELL AS MID
LEVEL MOISTURE DEPTH DEEPENS...BUT THAT WOULD ONLY HELP MATTERS.
OUTSIDE OF THE ADVISORY...NO MAJOR CHANGES NEEDED.
UPDATE ISSUED AT 933 PM EST THU NOV 29 2012
EVENT STARTING TO GET UNDERWAY OVER THE PAST 2 HOURS...WITH A
NARROW BUT WELL-DEFINED AXIS OF LIGHT RADAR RETURNS CENTERED JUST
SOUTH OF THE M-32 CORRIDOR. THIS IS ALONG A SHALLOW (925-875MB)
AXIS OF FRONTOGENESIS AS LOW LEVEL ARCTIC AIR CONTINUES TO BLEED
BENEATH WARMER REGIME ALOFT. PER OBS OUT THE WINDOW...WE HAVE SEEN
BOTH SOME LIGHT SNOW AND FREEZING DRIZZLE...CONSISTENT WITH 00Z
APX RAOB SHOWING SATURATION NEARING -10C...AND A DEEPENING OF THE
COLD WITHIN THE SATURATED LAYER (LEADING TO MORE OF A FROZEN
DRIZZLE SCENARIO EARLIER). SUSPECT THIS WILL BE THE CASE
OVERNIGHT...AND PER SHORT TERM GUIDANCE TRENDS...HAVE REWORKED
POPS/WEATHER TO FOCUS INITIALLY ON THE HIGHER TERRAIN.
HOWEVER...SUSPECT PRECIP WILL BECOME MUCH MORE WIDESPREAD AFTER
06Z AS A RATHER ROBUST UPPER WAVE BEGINS ITS APPROACH...AND LOW
LEVEL WARM ADVECTION ASCENT CRANKS UP (ALBEIT STILL FAIRLY WEAK).
ALSO SEEING A GRADUAL TOP-DOWN SATURATION ONGOING PER HIGHER RADAR
SCANS...AND GIVEN THIS AND STRONG QPF SIGNAL FROM ALL AVAILABLE
GUIDANCE...HAVE TO BELIEVE WE WILL END UP SEEING A PERIOD OF
LIGHTER SNOWS ACROSS MUCH OF NORTHERN LOWER LATER TONIGHT AS
SEEDER-FEEDER MECHANISM BASICALLY ERADICATES THE INITIALLY QUITE
DRY 650-550MB LAYER. HAVE ALSO BUMPED POPS TO LIKELY FOR AREAS
MAINLY NORTH OF M-72...WHILE DOWNSLOPE REGIME FOR GRAND TRAVERSE
BAY REGION PROBABLY HELPS HOLD MUCH IN THE WAY OF PRECIP AT BAY
(MAYBE JUST SOME FLURRIES OR VERY LIGHT FREEZING DRIZZLE. WILL OF
COURSE HAVE TO KEEP WATCHING AND WILL FINE-TUNE THINGS FURTHER
WITH TIME...BUT STILL LIKE THE IDEA THAT COMBO OF LIGHT SNOW AND
FREEZING DRIZZLE MAY MAKE FOR SOME SLIPPERY TRAVEL LATER TONIGHT
INTO FRIDAY MORNING...PARTICULARLY INTO THE HIGHER TERRAIN WHERE
ROBUST INVERSION-LEVEL EASTERLY JET OF 30 KNOTS WILL ONLY AID IN
UPSLOPE FORCING.
UPDATE ISSUED AT 653 PM EST THU NOV 29 2012
AS CONVOLUTED OF A FORECAST AS THEY COME THIS TIME OF YEAR IN
NORTHERN MICHIGAN...WITH THE MAIN CONCERN BEING THE POTENTIAL FOR
FREEZING DRIZZLE AND/OR SNOW (MAYBE BOTH) OVERNIGHT. PER 23Z
SURFACE ANALYSIS...SHARP ARCTIC BOUNDARY LIES BETWEEN M-55 AND
US-10...BEING DRIVEN SLOWLY SOUTHWARD WITH TIME COURTESY OF STRONG
(1037MB) ARCTIC HIGH DRIFTING THROUGH ONTARIO. AS PREDICTED BY THE
DAY CREW...WEAKISH BUT DEEPENING WARM ADVECTION ASCENT NORTH OF
THIS BOUNDARY (AND ABOVE A RATHER CHILLY LOW LEVEL SUB-925MB
AIRMASS) IS FUELING THE GRADUAL DEVELOPMENT OF LOWER CLOUDS. RADAR
RETURNS ALSO ON THE INCREASE ACROSS THE HIGHER TERRAIN AS THE SUB-
925MB FLOW IS VEERING MORE EASTERLY WITH TIME AND UPSLOPE
COMPONENT IS ON THE INCREASE. PER OBS OUT THE WINDOW HERE (HARD TO
BEAT ACTUAL OBS)...PRECIP TYPE IS JUST FLURRIES...WITH A SATURATED
PROFILE UP TO -10C PER INCOMING 00Z APX RAOB...JUST SUFFICIENT FOR
ICE NUCLEI PRODUCTION. THAT DOESN`T MAKE OUR JOB ANY EASIER
OVERNIGHT WITH REGARD TO PRECIP TYPE FORECASTING...AS IT WAS
THOUGHT PRECIP MAY INITIALLY BE MORE OF THE LIQUID VARIETY (FZDZ)
BEFORE POSSIBLY BECOMING MORE SNOW LATER AS SEEDER-FEEDER
MECHANISM KICKS INTO GEAR.
AT THIS POINT...DON`T PLAN TO MAKE ANY MAJOR CHANGES TO GOING
FORECAST...BUT WILL HAVE TO CLOSELY WATCH OBS THE NEXT FEW HOURS.
PER OBS...MAY HAVE TO SLOW DOWN PRECIP MENTION NORTH OF M-68
(MAYBE NORTH OF M-32) AS LOW LEVEL NORTHERLY FLOW IS BLEEDING IN
SIGNIFICANTLY DRIER AIR (SEE DEW POINTS FALLING THROUGH THE
TEENS)...IMPEDING LOWER CLOUD DEVELOPMENT. WITH REALLY NO CHANGE
TO LOW LEVEL THERMAL PROFILES PER SHORT TERM GUIDANCE TRENDS THE
NEXT FEW HOURS...MAY HAVE TO REMOVE THE FZDZ MENTION THROUGH 04Z
OR SO. HOWEVER...RUC/HI-RES 4KM NAM RAOBS CONTINUE TO HINT AT LOSS
OF MOISTURE BETWEEN -7C AND -4C BY 06Z...FAVORING MORE OF A LIQUID
SCENARIO WITH TIME. ONE CONCERN AREA IS ALSO SOUTH OF GRAND
TRAVERSE BAY...AS LOW LEVEL STRONGER EASTERLY FLOW WILL BE A
DOWNSLOPE ONE AND MAY ACT TO HOLD CEILINGS UP AND THUS ELIMINATE
THE POTENTIAL FOR ANY FREEZING DRIZZLE WHATSOEVER.
WILL ALSO LIKELY HAVE TO UP WINDS OVERNIGHT AS A STRONG GRADIENT
DEVELOPS DIRECTLY OVERHEAD...WITH A PRONOUNCED 25-30 KNOT EASTERLY
LOW LEVEL JET RIGHT AT INVERSION LEVEL. GIVEN AN UNSTABLE SUB-
925MB PROFILE...SHOULD HAVE NO BIG TROUBLE GETTING STRONGER GUSTS
TO MIX DOWN...PARTICULARLY AFTER 04Z. GOING LOWS LOOK JUST FINE AT
THIS POINT...PERHAPS EVEN SLIGHTLY COLDER FOR EASTERN UPPER (A FEW
SINGLE DIGITS?) AS VERY DENSE/COLD ARCTIC AIR OOZES INTO THAT AREA
FROM ONTARIO.
&&
.SHORT TERM...(THIS EVENING THROUGH FRIDAY)
ISSUED AT 406 PM EST THU NOV 29 2012
SHALLOW ARCTIC BOUNDARY CONTINUES ITS SLOW TREK SOUTH ACROSS
NORTHERN LOWER THIS AFTERNOON...COURTESY OF 1033MB HIGH BUILDING
EAST INTO WESTERN ONTARIO. LACK OF DYNAMICS AND DEARTH OF DEEP LAYER
MOISTURE ALLOWING A DRY FRONTAL PASSAGE...ALTHOUGH WELL DEFINED
STRATUS DECK BUILDING SOUTH IN ITS WAKE. TEMPERATURE CHANGE NOT AN
OVERLY ABRUPT ONE DIRECTLY BEHIND THE FRONT...WITH READING COOLING
BACK INTO THE LOWER AND MIDDLE 30S OVER NORTHERN LOWER MICHIGAN.
HEART OF THE COLDEST AIR REMAINS JUST NORTH OF THE BORDER...WITH
READINGS STUCK IN THE SINGLE DIGITS EVEN AT THIS HOUR. QUIET WEATHER
LOOKS TO BE SHORT-LIVED...WITH MOUNTING EVIDENCE FOR A POTENTIAL
HIGH IMPACT FREEZING DRIZZLE EVENT TONIGHT INTO FRIDAY MORNING.
FORECAST CONCERNS CENTER ON SUCH...SPECIFICALLY SPATIAL AND TEMPORAL
RESOLUTION OF FREEZING DRIZZLE TONIGHT INTO FRIDAY...AS WELL AS
ASSOCIATED HEADLINE POSSIBILITIES.
NO SHORTAGE OF THINGS TO TALK ABOUT TONIGHT. SHALLOW FRONT CONTINUES
TO SAG SOUTH...EVENTUALLY STALLING OUT OVER THE NORTHERN OHIO VALLEY
FRIDAY MORNING AS SUBTLE MID LEVEL WAVE ENTICES WEAKISH LOW PRESSURE
DEVELOPMENT ALONG IT. THIS WILL FORCE WEAK BUT SUSTAINED WAA UP AND
OVER THE SHALLOW NORTHERN LAKES SURFACE BASED COLD DOME. LOW LEVEL
MOISTURE ALREADY IN PLACE AS EVIDENT BY EXPANDING STRATUS DECK...
WITH SAID WAA ONLY DEEPENING THE MOIST LAYER. MODEL DERIVED
SOUNDINGS CONFIRM AS SUCH...WITH INCREASING MIXING RATIOS WITH HEIGHT
AND NEAR SATURATED CONDITIONS TO THE SURFACE. COMBINE THIS WILL A
MOIST LAYER LYING ENTIRELY WARMER THAN -10C AND A MID LEVEL DRY
WEDGE/WEAK WIND SHEAR DIRECTLY ABOVE THE MOIST LAYER...AND THE
SUPPORT IS HIGH FOR A DEVELOPING FREEZING DRIZZLE EVENT OVERNIGHT AS
SURFACE TEMPERATURES DROP. MAINTENANCE OF LOW LEVEL INSTABILITY
REGIME ACROSS NORTHERN LAKE HURON WILL ONLY AUGMENT THE LOW LEVEL
MOISTURE ACROSS NORTHEAST LOWER AND THE INTERIOR HIGHLANDS ALONG AND
EAST OF INTERSTATE 75. LAKE CONVECTION MAY BE DEEP ENOUGH TO SUPPORT
LIGHT SNOW SHOWER DEVELOPMENT IN THESE AREAS...ALTHOUGH EVEN HERE
SOUNDINGS ARE MORE SUPPORTIVE OF FREEZING DRIZZLE. WILL USE OFF THE
DECK WAA MOISTENING FOR TEMPORAL AND SPATIAL DETAIL...EXPECTING
INITIAL FREEZING DRIZZLE TO DEVELOP ACROSS THE SOUTHEAST LATER THIS
EVENING...EXPANDING NORTH ACROSS THE REST OF NORTHERN LOWER BY
MORNING. DRY NORTHEAST FLOW LIKELY TO KEEP MUCH OF EASTERN UPPER DRY
OVERNIGHT. POLICY IS NOT TO BE TOO AGGRESSIVE WITH FREEZING DRIZZLE
HEADLINES...ESPECIALLY WITH NOTORIOUS HIGH BUST POTENTIAL OF SUCH.
PREFER TO HIGHLIGHT THE POTENTIAL FOR NOW WITH AN SPECIAL WEATHER
STATEMENT AND THROUGH HWO/HEADLINE NEWS FEATURES...PASSING POSSIBLE
HEADLINE DECISIONS TO THE EVENING CREW.
TEMPERATURES TONIGHT RATHER TRICKY...ALTHOUGH EXTENSIVE OVERCAST
LIKELY TO KEEP THINGS FROM GETTING TOO OUT OF HAND. WHILE LOW LEVEL
MOISTURE IS LIKELY TO STRIP OUT OF EASTERN UPPER OVERNIGHT...STILL
PLENTY OF MID LEVEL CLOUDS EXPECTED. THIS SHOULD KEEP READING
SOMEWHAT IN CHECK...ALTHOUGH SIMPLE MAGNITUDE OF COLD AIR JUST TO
THEIR NORTH ARGUES FOR TEMPERATURES DROPPING INTO THE LOWER AND
MIDDLE TEENS NORTH OF THE MIGHT MAC. CONSIDERABLY WARMER TO THE
SOUTH...WITH LOWS GENERALLY IN THE 20S.
ABOVE CONDITIONS APPLY RIGHT THROUGH FRIDAY...WITH GREATER EMPHASIS
ONCE AGAIN FOCUSED ACROSS INTERIOR AND NORTHEAST LOWER. MAY SEE SOME
SEEDING FROM INCREASED MID LEVEL MOISTURE LATER IN THE MORNING AND
AFTERNOON TO FORCE MORE OF A LIGHT SNOW ISSUE (JUST MINOR
ACCUMULATIONS)...BUT STILL CANNOT RULE OUT FREEZING DRIZZLE.
TEMPERATURES SLOWLY WARM...WITH READINGS ACROSS SOUTHERN ZONES
TOPPING THE FREEZING MARK BY LATE MORNING AND AFTERNOON. INFLUX OF
SHALLOW COLD AIR LIKELY TO KEEP EASTERN UPPER STUCK IN THE
20S.
&&
.LONG TERM...(FRIDAY NIGHT THROUGH THURSDAY)
ISSUED AT 406 PM EST THU NOV 29 2012
LARGE SCALE PATTERN/FORECAST: HEMISPHERIC PATTERN REMAINS DOMINATED
BY POLAR VORTICES OVER ARCTIC CANADA AND SIBERIA...AND A LARGE
TROUGH OVER THE EASTERN PACIFIC (FOCUSING COPIOUS AMOUNTS OF
PRECIPITATION INTO THE WEST COAST)...MAKING UP THREE WAVES OF AN
ODDLY SHAPED FOUR WAVE PATTERN. THIS OVERALL IDEA LOOKS PRETTY
ENTRENCHED THIS FORECAST CYCLE...AS CENTRAL PACIFIC/-WPO REX
BLOCKING HELPS ANCHOR THE PATTERN. FLOW ACROSS THE CONUS HOWEVER IS
BECOMING FLATTER/MORE ZONAL WITH TIME...ONE RIPPLE EMANATING FROM
THE EASTERN PACIFIC STORM WILL CROSS THE CONUS AND PASS THE GREAT
LAKES/OHIO VALLEY FRIDAY...WITH A STRONGER WAVE COMING IN THE
TUESDAY TIME FRAME AS PACIFIC TROUGH RE-LOADS ALLOWING FOR A
TEMPORARY BREAK IN WHAT IS OTHERWISE A MILD LOOKING PATTERN.
WEST-EAST ORIENTED COLD FRONT DRAPED ACROSS NORTHERN LOWER MICHIGAN
TODAY...SANDWICHED BETWEEN HIGH PRESSURE OVER THE CAROLINAS AND
ARCTIC HIGH OVER NORTHERN MANITOBA RIDGING EAST ACROSS NORTHERN
ONTARIO. FRONT WILL SAG INTO SOUTHERN LOWER MICHIGAN AND STALL...
ALLOWING COLD NORTHEAST/EAST BOUNDARY LAYER FLOW TO DEVELOP INTO
NORTHERN MICHIGAN (SINGLE DIGIT TEMPERATURES ABOVE AND BELOW ZERO TO
THE NORTH AND EAST OF LAKE SUPERIOR). UPPER LEVEL DISTURBANCE
CROSSING THE NORTHERN/CENTRAL ROCKIES TODAY WILL CROSS SOUTHERN
LOWER MICHIGAN/INDIANA/OHIO FRIDAY...AND ANOTHER WEAK RIPPLE
SATURDAY NIGHT ALONG WITH A SURFACE TROUGH/COLD FRONT. NEAR TERM
FORECAST CONCERNS WILL DEAL WITH WARM ADVECTION ABOVE SHALLOW FRONT
SOUTH OF THE STATE FRIDAY NIGHT INTO EARLY SATURDAY...THEN RAIN
SHOWER THREAT SATURDAY NIGHT INTO SUNDAY.
FRIDAY NIGHT THROUGH SUNDAY: FORECAST STARTS WITH SHORT WAVE ENERGY
MOVING AWAY FROM NORTHERN MICHIGAN TO THE SOUTHEAST...WITH LOW LEVEL
EASTERLY FLOW CONTINUING AROUND REMNANT ARCTIC HIGH OVER QUEBEC.
STILL LOOKS TO BE A LOT OF LOW LEVEL MOISTURE AROUND STUCK BENEATH
FRONTAL INVERSION...WARM ADVECTION/UPSLOPE FLOW/SHALLOW LAKE
CONVECTION WILL ALL CONTRIBUTE SOME FORCING FOR A CONTINUED THREAT
FOR DRIZZLE/FREEZING DRIZZLE (AND PERHAPS SOME FOG AS WELL WITH
STRATUS BUILD DOWN...ESPECIALLY ON THE HILLTOPS). THIS CONTINUES
INTO SATURDAY MORNING...BUT WITH AN INCREASING SOUTHERLY WIND
EXPECTING TEMPERATURES TO CLIMB ABOVE FREEZING DURING THE MORNING
HOURS. LOOKING LIKE LOW CLOUDS WILL BE STUBBORN ACROSS EASTERN
UPPER (ALONG WITH THE DRIZZLE) AND MUCH OF NORTHEAST LOWER INTO THE
AFTERNOON... WHILE THINK WE`LL SEE SOME SUN DEVELOP ACROSS NORTHWEST
LOWER AND DOWN TOWARDS SAGINAW BAY.
COLD FRONT WILL BE MOVING ACROSS MICHIGAN SATURDAY NIGHT...WITH AN
AXIS OF LOW LEVEL MOISTURE ALONG IT. RIGHT ENTRANCE JET QUADRANT
WILL ENHANCE DIVERGENCE ACROSS THE FORECAST AREA...WITH THE END
RESULT BEING A BAND OF SHOWERS DEVELOPING AHEAD OF THE FRONT AND
CROSSING THE FORECAST AREA. EXPECT TEMPERATURES TO BE STEADY OR
SLOWLY CLIMB OVERNIGHT. COLD FRONT PASSAGE SUNDAY MORNING WILL
BRING AN END TO RAIN CHANCES DURING THE MORNING...THOUGH SOME
UNCERTAINTY WITH RESPECT TO EXACT FRONTAL TIMING SO WILL TRY TO BE
SOMEWHAT PROBABILISTIC WITH RESPECT TO RAIN CHANCES SUNDAY AS
OPPOSED TO GRABBING ONTO ONE MODEL SOLUTION. WILL TRY TO CONFINE
RAIN SHOWERS TO JUST THE MORNING HOURS.
EXTENDED FORECAST (MONDAY THROUGH THURSDAY): STRONG HEIGHT FALLS
PUSHING ACROSS THE MIDWEST ON MONDAY WILL SEND A SURGE OF SOUTHERLY
MOMENTUM AND WARM AIR UP INTO THE GREAT LAKES. AS MENTIONED IN THIS
SPACE YESTERDAY BIGGEST UNKNOWN IS POTENTIAL FOR LOW CLOUDS/
ADVECTION FOG ALONG AXIS OF HIGHER DEW POINT AIR ALONG COLD FRONT
ASSOCIATED WITH APPROACHING SHORT WAVE. BUT WILL CONTINUE WITH
POSITIVE THOUGHTS AND HIGHS IN THE 50S MOST AREAS MONDAY AFTERNOON.
STRONG COLD FRONT WILL SWEEP THROUGH THE UPPER LAKES MONDAY NIGHT
INTO EARLY TUESDAY... TIMING OF THE FRONT WILL HAVE HUGE
IMPLICATIONS WITH RESPECT TO HIGH TEMPERATURES (AS THE MERCURY IS
LIKELY TO FALL THROUGH THE DAY) AND PRECIPITATION (LINGERING SHOWERS
IF FRONT IS SLOWER...QUICKER ONSET OF LAKE CONVECTION IF BOUNDARY IS
THROUGH THE AREA TUESDAY MORNING). A QUICKER TREND MAY BE THE WAY
TO GO...WHICH DRIES THE BULK OF TUESDAY OUT. HEADING INTO
MIDWEEK...HIGH PRESSURE SLIDES ACROSS THE MIDWEST AND INTO THE UPPER
LAKES...WITH ANOTHER ROUND OF WARM ADVECTION SETTING UP FOR
THURSDAY. WEDNESDAY WILL PROBABLY BE A TRANSITION FROM LAKE
CONVECTION TO DRY WEATHER...AND WILL PROBABLY START THE NEW THURSDAY
FORECAST DRY AS WELL.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z FRIDAY NIGHT)
ISSUED AT 1145 PM EST THU NOV 29 2012
VFR/MVFR CONDITIONS INITIALLY WILL FALL TO IFR FOR APN/PLN THE
REMAINDER OF THE NIGHT AS SOME FREEZING DRIZZLE AND LIGHT SNOW
DEVELOP AHEAD OF AN APPROACHING UPPER WAVE. MEANWHILE...TVC AND
MBL LOOK TO BE JUST A BIT TOO FAR WEST TO RECEIVE ANY SIGNIFICANT
FREEZING DRIZZLE...AIDED BY FURTHER DRYING DOWN LOW AS EASTERLY
DOWNSLOPE WINDS PREVAIL. CONDITIONS MAY BRIEFLY TRY TO IMPROVE
FRIDAY AFTERNOON...BUT SHOULD STILL REMAIN IFR TO MVFR WITHIN
LOWER CLOUDS...BEFORE THICKER LOW STRATUS AND PERHAPS SOME MORE
FREEZING DRIZZLE RETURNS FOR ALL TERMINAL SITES AFTER 00Z. WINDS
WILL BECOME A LITTLE GUSTY FROM THE EAST AT ALL SITES...WITH
PERHAPS A FEW GUSTS PUSHING 20 KNOTS ON FRIDAY.
&&
.MARINE...
ISSUED AT 933 PM EST THU NOV 29 2012
UPDATE: HAVE ISSUED SMALL CRAFT ADVISORIES FROM SEUL CHOIX POINT
TO THE BRIDGE WHERE EASTERLY FLOW IS BEGINNING TO CHANNEL THROUGH
THE STRAITS...AND SHOULD ONLY INCREASE WITH TIME THROUGH THE NIGHT
WITHING A DECENT GRADIENT.
INCREASINGLY GUSTY NORTHEAST TO EAST WINDS WILL RESULT
IN SCA CONDITIONS FOR MOST OF THE NEARSHORE WATERS OF BOTH NORTHERN
LAKE MICHIGAN AND HURON FROM LATE TONIGHT RIGHT THROUGH FRIDAY
AFTERNOON. WINDS BEGIN TO SUBSIDE SOME FRIDAY NIGHT INTO
SATURDAY...EVENTUALLY VEERING SOUTHERLY BY LATER SATURDAY. MAY NEED
SOME EXTENSIONS TO ONGOING ADVISORIES...ESPECIALLY ACROSS LAKE
HURON...THROUGH THIS PERIOD.
&&
.APX WATCHES/WARNINGS/ADVISORIES...
MI...WINTER WEATHER ADVISORY UNTIL 9 AM EST FRIDAY FOR MIZ016>019-
021>024-027>030.
LH...SMALL CRAFT ADVISORY UNTIL 4 PM EST FRIDAY FOR LHZ345>349.
LM...SMALL CRAFT ADVISORY UNTIL 4 PM EST FRIDAY FOR LMZ323-341-342-
344-345.
LS...NONE.
&&
$$
UPDATE...LAWRENCE
SYNOPSIS...TJL
SHORT TERM...MSB
LONG TERM...JPB
AVIATION...LAWRENCE
MARINE...MSB/LAWRENCE
AREA FORECAST DISCUSSION
NWS GAYLORD MI
1102 PM EST THU NOV 29 2012
.SYNOPSIS...
ISSUED AT 406 PM EST THU NOV 29 2012
THE SEASONABLY CHILLY AIR WILL CONTINUE TO HANG ACROSS THE REGION
THROUGH FRIDAY...BRINGING A BIT MORE LIGHT SNOW SHOWERS OR FLURRIES
AT TIMES. PERHAPS EVEN SOME FREEZING DRIZZLE LATER TONIGHT INTO
FRIDAY MORNING. MILDER TEMPERATURES AND RAIN CHANCES...WILL MAKE A
RETURN TO NORTHERN MICHIGAN THIS WEEKEND...AND INTO EARLY NEXT
WEEK...AS A PAIR OF SYSTEMS MOVE OVER THE NORTHERN PLAINS AND PASS
NORTHWEST OF THE STATE.
&&
.UPDATE...
ISSUED AT 1102 PM EST THU NOV 29 2012
EARLIER FCST UPDATE ACTUALLY WORKING OUT RATHER WELL (THAT DOESN`T
ALWAYS HAPPEN HERE!)...AND PER LATEST RADAR/RAP TRENDS...HAVE
DECIDED TO HOIST A WINTER WEATHER ADVISORY BASICALLY FROM M-72 ON
NORTH THROUGH MID MORNING. ALREADY SEEING A NICE COATING OF ICE
HERE AT THE OFFICE AND ACROSS THE HIGHER TERRAIN PER SPOTTER
REPORTS. PER RAP GUIDANCE (WHICH HAD THE BEST HANDLE OF BLOSSOMING
OF PRECIP EARLIER)...BEST LOW LEVEL WARM ADVECTION ASCENT IN THE
925-875MB LAYER WILL OCCUR BASICALLY NORTH OF M-72 OVERNIGHT. THAT
DOESN`T PRECLUDE SOME PATCHY FREEZING DRIZZLE TO THE SOUTH...
ESPECIALLY GIVEN STALLING ARCTIC FRONTAL BOUNDARY DOWN THAT WAY
AND BETTER POOLED MOISTURE...BUT CURRENT ADVISORY AREA IS MY BEST
GUESS WHERE THINGS MAY GET QUITE SLICK BY MORNING. CAN FORESEE A
BIT OF A MIX WITH SOME SNOW AT TIMES LATER TONIGHT AS WELL AS MID
LEVEL MOISTURE DEPTH DEEPENS...BUT THAT WOULD ONLY HELP MATTERS.
OUTSIDE OF THE ADVISORY...NO MAJOR CHANGES NEEDED.
UPDATE ISSUED AT 933 PM EST THU NOV 29 2012
EVENT STARTING TO GET UNDERWAY OVER THE PAST 2 HOURS...WITH A
NARROW BUT WELL-DEFINED AXIS OF LIGHT RADAR RETURNS CENTERED JUST
SOUTH OF THE M-32 CORRIDOR. THIS IS ALONG A SHALLOW (925-875MB)
AXIS OF FRONTOGENESIS AS LOW LEVEL ARCTIC AIR CONTINUES TO BLEED
BENEATH WARMER REGIME ALOFT. PER OBS OUT THE WINDOW...WE HAVE SEEN
BOTH SOME LIGHT SNOW AND FREEZING DRIZZLE...CONSISTENT WITH 00Z
APX RAOB SHOWING SATURATION NEARING -10C...AND A DEEPENING OF THE
COLD WITHIN THE SATURATED LAYER (LEADING TO MORE OF A FROZEN
DRIZZLE SCENARIO EARLIER). SUSPECT THIS WILL BE THE CASE
OVERNIGHT...AND PER SHORT TERM GUIDANCE TRENDS...HAVE REWORKED
POPS/WEATHER TO FOCUS INITIALLY ON THE HIGHER TERRAIN.
HOWEVER...SUSPECT PRECIP WILL BECOME MUCH MORE WIDESPREAD AFTER
06Z AS A RATHER ROBUST UPPER WAVE BEGINS ITS APPROACH...AND LOW
LEVEL WARM ADVECTION ASCENT CRANKS UP (ALBEIT STILL FAIRLY WEAK).
ALSO SEEING A GRADUAL TOP-DOWN SATURATION ONGOING PER HIGHER RADAR
SCANS...AND GIVEN THIS AND STRONG QPF SIGNAL FROM ALL AVAILABLE
GUIDANCE...HAVE TO BELIEVE WE WILL END UP SEEING A PERIOD OF
LIGHTER SNOWS ACROSS MUCH OF NORTHERN LOWER LATER TONIGHT AS
SEEDER-FEEDER MECHANISM BASICALLY ERADICATES THE INITIALLY QUITE
DRY 650-550MB LAYER. HAVE ALSO BUMPED POPS TO LIKELY FOR AREAS
MAINLY NORTH OF M-72...WHILE DOWNSLOPE REGIME FOR GRAND TRAVERSE
BAY REGION PROBABLY HELPS HOLD MUCH IN THE WAY OF PRECIP AT BAY
(MAYBE JUST SOME FLURRIES OR VERY LIGHT FREEZING DRIZZLE. WILL OF
COURSE HAVE TO KEEP WATCHING AND WILL FINE-TUNE THINGS FURTHER
WITH TIME...BUT STILL LIKE THE IDEA THAT COMBO OF LIGHT SNOW AND
FREEZING DRIZZLE MAY MAKE FOR SOME SLIPPERY TRAVEL LATER TONIGHT
INTO FRIDAY MORNING...PARTICULARLY INTO THE HIGHER TERRAIN WHERE
ROBUST INVERSION-LEVEL EASTERLY JET OF 30 KNOTS WILL ONLY AID IN
UPSLOPE FORCING.
UPDATE ISSUED AT 653 PM EST THU NOV 29 2012
AS CONVOLUTED OF A FORECAST AS THEY COME THIS TIME OF YEAR IN
NORTHERN MICHIGAN...WITH THE MAIN CONCERN BEING THE POTENTIAL FOR
FREEZING DRIZZLE AND/OR SNOW (MAYBE BOTH) OVERNIGHT. PER 23Z
SURFACE ANALYSIS...SHARP ARCTIC BOUNDARY LIES BETWEEN M-55 AND
US-10...BEING DRIVEN SLOWLY SOUTHWARD WITH TIME COURTESY OF STRONG
(1037MB) ARCTIC HIGH DRIFTING THROUGH ONTARIO. AS PREDICTED BY THE
DAY CREW...WEAKISH BUT DEEPENING WARM ADVECTION ASCENT NORTH OF
THIS BOUNDARY (AND ABOVE A RATHER CHILLY LOW LEVEL SUB-925MB
AIRMASS) IS FUELING THE GRADUAL DEVELOPMENT OF LOWER CLOUDS. RADAR
RETURNS ALSO ON THE INCREASE ACROSS THE HIGHER TERRAIN AS THE SUB-
925MB FLOW IS VEERING MORE EASTERLY WITH TIME AND UPSLOPE
COMPONENT IS ON THE INCREASE. PER OBS OUT THE WINDOW HERE (HARD TO
BEAT ACTUAL OBS)...PRECIP TYPE IS JUST FLURRIES...WITH A SATURATED
PROFILE UP TO -10C PER INCOMING 00Z APX RAOB...JUST SUFFICIENT FOR
ICE NUCLEI PRODUCTION. THAT DOESN`T MAKE OUR JOB ANY EASIER
OVERNIGHT WITH REGARD TO PRECIP TYPE FORECASTING...AS IT WAS
THOUGHT PRECIP MAY INITIALLY BE MORE OF THE LIQUID VARIETY (FZDZ)
BEFORE POSSIBLY BECOMING MORE SNOW LATER AS SEEDER-FEEDER
MECHANISM KICKS INTO GEAR.
AT THIS POINT...DON`T PLAN TO MAKE ANY MAJOR CHANGES TO GOING
FORECAST...BUT WILL HAVE TO CLOSELY WATCH OBS THE NEXT FEW HOURS.
PER OBS...MAY HAVE TO SLOW DOWN PRECIP MENTION NORTH OF M-68
(MAYBE NORTH OF M-32) AS LOW LEVEL NORTHERLY FLOW IS BLEEDING IN
SIGNIFICANTLY DRIER AIR (SEE DEW POINTS FALLING THROUGH THE
TEENS)...IMPEDING LOWER CLOUD DEVELOPMENT. WITH REALLY NO CHANGE
TO LOW LEVEL THERMAL PROFILES PER SHORT TERM GUIDANCE TRENDS THE
NEXT FEW HOURS...MAY HAVE TO REMOVE THE FZDZ MENTION THROUGH 04Z
OR SO. HOWEVER...RUC/HI-RES 4KM NAM RAOBS CONTINUE TO HINT AT LOSS
OF MOISTURE BETWEEN -7C AND -4C BY 06Z...FAVORING MORE OF A LIQUID
SCENARIO WITH TIME. ONE CONCERN AREA IS ALSO SOUTH OF GRAND
TRAVERSE BAY...AS LOW LEVEL STRONGER EASTERLY FLOW WILL BE A
DOWNSLOPE ONE AND MAY ACT TO HOLD CEILINGS UP AND THUS ELIMINATE
THE POTENTIAL FOR ANY FREEZING DRIZZLE WHATSOEVER.
WILL ALSO LIKELY HAVE TO UP WINDS OVERNIGHT AS A STRONG GRADIENT
DEVELOPS DIRECTLY OVERHEAD...WITH A PRONOUNCED 25-30 KNOT EASTERLY
LOW LEVEL JET RIGHT AT INVERSION LEVEL. GIVEN AN UNSTABLE SUB-
925MB PROFILE...SHOULD HAVE NO BIG TROUBLE GETTING STRONGER GUSTS
TO MIX DOWN...PARTICULARLY AFTER 04Z. GOING LOWS LOOK JUST FINE AT
THIS POINT...PERHAPS EVEN SLIGHTLY COLDER FOR EASTERN UPPER (A FEW
SINGLE DIGITS?) AS VERY DENSE/COLD ARCTIC AIR OOZES INTO THAT AREA
FROM ONTARIO.
&&
.SHORT TERM...(THIS EVENING THROUGH FRIDAY)
ISSUED AT 406 PM EST THU NOV 29 2012
SHALLOW ARCTIC BOUNDARY CONTINUES ITS SLOW TREK SOUTH ACROSS
NORTHERN LOWER THIS AFTERNOON...COURTESY OF 1033MB HIGH BUILDING
EAST INTO WESTERN ONTARIO. LACK OF DYNAMICS AND DEARTH OF DEEP LAYER
MOISTURE ALLOWING A DRY FRONTAL PASSAGE...ALTHOUGH WELL DEFINED
STRATUS DECK BUILDING SOUTH IN ITS WAKE. TEMPERATURE CHANGE NOT AN
OVERLY ABRUPT ONE DIRECTLY BEHIND THE FRONT...WITH READING COOLING
BACK INTO THE LOWER AND MIDDLE 30S OVER NORTHERN LOWER MICHIGAN.
HEART OF THE COLDEST AIR REMAINS JUST NORTH OF THE BORDER...WITH
READINGS STUCK IN THE SINGLE DIGITS EVEN AT THIS HOUR. QUIET WEATHER
LOOKS TO BE SHORT-LIVED...WITH MOUNTING EVIDENCE FOR A POTENTIAL
HIGH IMPACT FREEZING DRIZZLE EVENT TONIGHT INTO FRIDAY MORNING.
FORECAST CONCERNS CENTER ON SUCH...SPECIFICALLY SPATIAL AND TEMPORAL
RESOLUTION OF FREEZING DRIZZLE TONIGHT INTO FRIDAY...AS WELL AS
ASSOCIATED HEADLINE POSSIBILITIES.
NO SHORTAGE OF THINGS TO TALK ABOUT TONIGHT. SHALLOW FRONT CONTINUES
TO SAG SOUTH...EVENTUALLY STALLING OUT OVER THE NORTHERN OHIO VALLEY
FRIDAY MORNING AS SUBTLE MID LEVEL WAVE ENTICES WEAKISH LOW PRESSURE
DEVELOPMENT ALONG IT. THIS WILL FORCE WEAK BUT SUSTAINED WAA UP AND
OVER THE SHALLOW NORTHERN LAKES SURFACE BASED COLD DOME. LOW LEVEL
MOISTURE ALREADY IN PLACE AS EVIDENT BY EXPANDING STRATUS DECK...
WITH SAID WAA ONLY DEEPENING THE MOIST LAYER. MODEL DERIVED
SOUNDINGS CONFIRM AS SUCH...WITH INCREASING MIXING RATIOS WITH HEIGHT
AND NEAR SATURATED CONDITIONS TO THE SURFACE. COMBINE THIS WILL A
MOIST LAYER LYING ENTIRELY WARMER THAN -10C AND A MID LEVEL DRY
WEDGE/WEAK WIND SHEAR DIRECTLY ABOVE THE MOIST LAYER...AND THE
SUPPORT IS HIGH FOR A DEVELOPING FREEZING DRIZZLE EVENT OVERNIGHT AS
SURFACE TEMPERATURES DROP. MAINTENANCE OF LOW LEVEL INSTABILITY
REGIME ACROSS NORTHERN LAKE HURON WILL ONLY AUGMENT THE LOW LEVEL
MOISTURE ACROSS NORTHEAST LOWER AND THE INTERIOR HIGHLANDS ALONG AND
EAST OF INTERSTATE 75. LAKE CONVECTION MAY BE DEEP ENOUGH TO SUPPORT
LIGHT SNOW SHOWER DEVELOPMENT IN THESE AREAS...ALTHOUGH EVEN HERE
SOUNDINGS ARE MORE SUPPORTIVE OF FREEZING DRIZZLE. WILL USE OFF THE
DECK WAA MOISTENING FOR TEMPORAL AND SPATIAL DETAIL...EXPECTING
INITIAL FREEZING DRIZZLE TO DEVELOP ACROSS THE SOUTHEAST LATER THIS
EVENING...EXPANDING NORTH ACROSS THE REST OF NORTHERN LOWER BY
MORNING. DRY NORTHEAST FLOW LIKELY TO KEEP MUCH OF EASTERN UPPER DRY
OVERNIGHT. POLICY IS NOT TO BE TOO AGGRESSIVE WITH FREEZING DRIZZLE
HEADLINES...ESPECIALLY WITH NOTORIOUS HIGH BUST POTENTIAL OF SUCH.
PREFER TO HIGHLIGHT THE POTENTIAL FOR NOW WITH AN SPECIAL WEATHER
STATEMENT AND THROUGH HWO/HEADLINE NEWS FEATURES...PASSING POSSIBLE
HEADLINE DECISIONS TO THE EVENING CREW.
TEMPERATURES TONIGHT RATHER TRICKY...ALTHOUGH EXTENSIVE OVERCAST
LIKELY TO KEEP THINGS FROM GETTING TOO OUT OF HAND. WHILE LOW LEVEL
MOISTURE IS LIKELY TO STRIP OUT OF EASTERN UPPER OVERNIGHT...STILL
PLENTY OF MID LEVEL CLOUDS EXPECTED. THIS SHOULD KEEP READING
SOMEWHAT IN CHECK...ALTHOUGH SIMPLE MAGNITUDE OF COLD AIR JUST TO
THEIR NORTH ARGUES FOR TEMPERATURES DROPPING INTO THE LOWER AND
MIDDLE TEENS NORTH OF THE MIGHT MAC. CONSIDERABLY WARMER TO THE
SOUTH...WITH LOWS GENERALLY IN THE 20S.
ABOVE CONDITIONS APPLY RIGHT THROUGH FRIDAY...WITH GREATER EMPHASIS
ONCE AGAIN FOCUSED ACROSS INTERIOR AND NORTHEAST LOWER. MAY SEE SOME
SEEDING FROM INCREASED MID LEVEL MOISTURE LATER IN THE MORNING AND
AFTERNOON TO FORCE MORE OF A LIGHT SNOW ISSUE (JUST MINOR
ACCUMULATIONS)...BUT STILL CANNOT RULE OUT FREEZING DRIZZLE.
TEMPERATURES SLOWLY WARM...WITH READINGS ACROSS SOUTHERN ZONES
TOPPING THE FREEZING MARK BY LATE MORNING AND AFTERNOON. INFLUX OF
SHALLOW COLD AIR LIKELY TO KEEP EASTERN UPPER STUCK IN THE
20S.
&&
.LONG TERM...(FRIDAY NIGHT THROUGH THURSDAY)
ISSUED AT 406 PM EST THU NOV 29 2012
LARGE SCALE PATTERN/FORECAST: HEMISPHERIC PATTERN REMAINS DOMINATED
BY POLAR VORTICES OVER ARCTIC CANADA AND SIBERIA...AND A LARGE
TROUGH OVER THE EASTERN PACIFIC (FOCUSING COPIOUS AMOUNTS OF
PRECIPITATION INTO THE WEST COAST)...MAKING UP THREE WAVES OF AN
ODDLY SHAPED FOUR WAVE PATTERN. THIS OVERALL IDEA LOOKS PRETTY
ENTRENCHED THIS FORECAST CYCLE...AS CENTRAL PACIFIC/-WPO REX
BLOCKING HELPS ANCHOR THE PATTERN. FLOW ACROSS THE CONUS HOWEVER IS
BECOMING FLATTER/MORE ZONAL WITH TIME...ONE RIPPLE EMANATING FROM
THE EASTERN PACIFIC STORM WILL CROSS THE CONUS AND PASS THE GREAT
LAKES/OHIO VALLEY FRIDAY...WITH A STRONGER WAVE COMING IN THE
TUESDAY TIME FRAME AS PACIFIC TROUGH RE-LOADS ALLOWING FOR A
TEMPORARY BREAK IN WHAT IS OTHERWISE A MILD LOOKING PATTERN.
WEST-EAST ORIENTED COLD FRONT DRAPED ACROSS NORTHERN LOWER MICHIGAN
TODAY...SANDWICHED BETWEEN HIGH PRESSURE OVER THE CAROLINAS AND
ARCTIC HIGH OVER NORTHERN MANITOBA RIDGING EAST ACROSS NORTHERN
ONTARIO. FRONT WILL SAG INTO SOUTHERN LOWER MICHIGAN AND STALL...
ALLOWING COLD NORTHEAST/EAST BOUNDARY LAYER FLOW TO DEVELOP INTO
NORTHERN MICHIGAN (SINGLE DIGIT TEMPERATURES ABOVE AND BELOW ZERO TO
THE NORTH AND EAST OF LAKE SUPERIOR). UPPER LEVEL DISTURBANCE
CROSSING THE NORTHERN/CENTRAL ROCKIES TODAY WILL CROSS SOUTHERN
LOWER MICHIGAN/INDIANA/OHIO FRIDAY...AND ANOTHER WEAK RIPPLE
SATURDAY NIGHT ALONG WITH A SURFACE TROUGH/COLD FRONT. NEAR TERM
FORECAST CONCERNS WILL DEAL WITH WARM ADVECTION ABOVE SHALLOW FRONT
SOUTH OF THE STATE FRIDAY NIGHT INTO EARLY SATURDAY...THEN RAIN
SHOWER THREAT SATURDAY NIGHT INTO SUNDAY.
FRIDAY NIGHT THROUGH SUNDAY: FORECAST STARTS WITH SHORT WAVE ENERGY
MOVING AWAY FROM NORTHERN MICHIGAN TO THE SOUTHEAST...WITH LOW LEVEL
EASTERLY FLOW CONTINUING AROUND REMNANT ARCTIC HIGH OVER QUEBEC.
STILL LOOKS TO BE A LOT OF LOW LEVEL MOISTURE AROUND STUCK BENEATH
FRONTAL INVERSION...WARM ADVECTION/UPSLOPE FLOW/SHALLOW LAKE
CONVECTION WILL ALL CONTRIBUTE SOME FORCING FOR A CONTINUED THREAT
FOR DRIZZLE/FREEZING DRIZZLE (AND PERHAPS SOME FOG AS WELL WITH
STRATUS BUILD DOWN...ESPECIALLY ON THE HILLTOPS). THIS CONTINUES
INTO SATURDAY MORNING...BUT WITH AN INCREASING SOUTHERLY WIND
EXPECTING TEMPERATURES TO CLIMB ABOVE FREEZING DURING THE MORNING
HOURS. LOOKING LIKE LOW CLOUDS WILL BE STUBBORN ACROSS EASTERN
UPPER (ALONG WITH THE DRIZZLE) AND MUCH OF NORTHEAST LOWER INTO THE
AFTERNOON... WHILE THINK WE`LL SEE SOME SUN DEVELOP ACROSS NORTHWEST
LOWER AND DOWN TOWARDS SAGINAW BAY.
COLD FRONT WILL BE MOVING ACROSS MICHIGAN SATURDAY NIGHT...WITH AN
AXIS OF LOW LEVEL MOISTURE ALONG IT. RIGHT ENTRANCE JET QUADRANT
WILL ENHANCE DIVERGENCE ACROSS THE FORECAST AREA...WITH THE END
RESULT BEING A BAND OF SHOWERS DEVELOPING AHEAD OF THE FRONT AND
CROSSING THE FORECAST AREA. EXPECT TEMPERATURES TO BE STEADY OR
SLOWLY CLIMB OVERNIGHT. COLD FRONT PASSAGE SUNDAY MORNING WILL
BRING AN END TO RAIN CHANCES DURING THE MORNING...THOUGH SOME
UNCERTAINTY WITH RESPECT TO EXACT FRONTAL TIMING SO WILL TRY TO BE
SOMEWHAT PROBABILISTIC WITH RESPECT TO RAIN CHANCES SUNDAY AS
OPPOSED TO GRABBING ONTO ONE MODEL SOLUTION. WILL TRY TO CONFINE
RAIN SHOWERS TO JUST THE MORNING HOURS.
EXTENDED FORECAST (MONDAY THROUGH THURSDAY): STRONG HEIGHT FALLS
PUSHING ACROSS THE MIDWEST ON MONDAY WILL SEND A SURGE OF SOUTHERLY
MOMENTUM AND WARM AIR UP INTO THE GREAT LAKES. AS MENTIONED IN THIS
SPACE YESTERDAY BIGGEST UNKNOWN IS POTENTIAL FOR LOW CLOUDS/
ADVECTION FOG ALONG AXIS OF HIGHER DEW POINT AIR ALONG COLD FRONT
ASSOCIATED WITH APPROACHING SHORT WAVE. BUT WILL CONTINUE WITH
POSITIVE THOUGHTS AND HIGHS IN THE 50S MOST AREAS MONDAY AFTERNOON.
STRONG COLD FRONT WILL SWEEP THROUGH THE UPPER LAKES MONDAY NIGHT
INTO EARLY TUESDAY... TIMING OF THE FRONT WILL HAVE HUGE
IMPLICATIONS WITH RESPECT TO HIGH TEMPERATURES (AS THE MERCURY IS
LIKELY TO FALL THROUGH THE DAY) AND PRECIPITATION (LINGERING SHOWERS
IF FRONT IS SLOWER...QUICKER ONSET OF LAKE CONVECTION IF BOUNDARY IS
THROUGH THE AREA TUESDAY MORNING). A QUICKER TREND MAY BE THE WAY
TO GO...WHICH DRIES THE BULK OF TUESDAY OUT. HEADING INTO
MIDWEEK...HIGH PRESSURE SLIDES ACROSS THE MIDWEST AND INTO THE UPPER
LAKES...WITH ANOTHER ROUND OF WARM ADVECTION SETTING UP FOR
THURSDAY. WEDNESDAY WILL PROBABLY BE A TRANSITION FROM LAKE
CONVECTION TO DRY WEATHER...AND WILL PROBABLY START THE NEW THURSDAY
FORECAST DRY AS WELL.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z FRIDAY EVENING)
ISSUED AT 653 PM EST THU NOV 29 2012
RATHER LOW CONFIDENCE FORECAST AS WE HEAD INTO THE NIGHTTIME
HOURS...WITH THE MAIN ISSUE BEING THE POTENTIAL FOR SOME LIGHT
SNOW AND FREEZING DRIZZLE. CURRENTLY SEEING A MIX OF MVFR AND VFR
CEILINGS ACROSS THE TAF SITES...AND SUSPECT CEILINGS WILL BE ON A
GRADUAL DOWNWARD TREND THROUGH THE NIGHT...AS LOW LEVEL MOISTURE
POOLS JUST NORTH OF A FRONTAL BOUNDARY STALLING OVER CENTRAL LOWER
MICHIGAN. SETUP IS THERE FOR FREEZING DRIZZLE DEVELOPMENT NORTH OF
THE FRONT OVERNIGHT...ESPECIALLY FOR PLN/APN WHERE EASTERLY FLOW
OFF LAKE HURON WILL HELP GIVE A LITTLE BETTER LOW LEVEL MOISTURE.
SAME EASTERLY FLOW WILL BE A DOWNSLOPE ONE FOR TVC/MBL...WHICH MAY
ACT TO HOLD CEILINGS A BIT HIGHER AND THUS REDUCE THE OVERALL
THREAT FOR FREEZING DRIZZLE. STILL...THE CHANCE IS NOT ZERO...AND
WILL MAKE A MENTION AT ALL SITES MINUS MBL...WHERE DOWNSLOPE
DRYING WILL PROBABLY WIN OUT. WILL LIKELY ALSO SEE A LITTLE SNOW
MIX WITH ANY FREEZING DRIZZLE...WITH THE OVERALL TREND TOWARD IFR
CONDITIONS FOR ALL SITES (MINUS PERHAPS MBL) LATER TONIGHT. WINDS
WILL BECOME GUSTY AT ALL SITES OVERNIGHT...WITH THE POTENTIAL FOR
SOME GUSTS PUSHING 25 KNOTS FOR A TIME. SOME SLOW IMPROVEMENT IS
EXPECTED FROM SOUTHWEST TO NORTHEAST THROUGH THE DAY ON
FRIDAY...BUT CEILINGS MAY HOLD IN THE IFR RANGE THROUGH MUCH OF
THE DAY AROUND PLN/APN.
&&
.MARINE...
ISSUED AT 933 PM EST THU NOV 29 2012
UPDATE: HAVE ISSUED SMALL CRAFT ADVISORIES FROM SEUL CHOIX POINT
TO THE BRIDGE WHERE EASTERLY FLOW IS BEGINNING TO CHANNEL THROUGH
THE STRAITS...AND SHOULD ONLY INCREASE WITH TIME THROUGH THE NIGHT
WITHING A DECENT GRADIENT.
INCREASINGLY GUSTY NORTHEAST TO EAST WINDS WILL RESULT
IN SCA CONDITIONS FOR MOST OF THE NEARSHORE WATERS OF BOTH NORTHERN
LAKE MICHIGAN AND HURON FROM LATE TONIGHT RIGHT THROUGH FRIDAY
AFTERNOON. WINDS BEGIN TO SUBSIDE SOME FRIDAY NIGHT INTO
SATURDAY...EVENTUALLY VEERING SOUTHERLY BY LATER SATURDAY. MAY NEED
SOME EXTENSIONS TO ONGOING ADVISORIES...ESPECIALLY ACROSS LAKE
HURON...THROUGH THIS PERIOD.
&&
.APX WATCHES/WARNINGS/ADVISORIES...
MI...WINTER WEATHER ADVISORY UNTIL 9 AM EST FRIDAY FOR MIZ016>019-
021>024-027>030.
LH...SMALL CRAFT ADVISORY UNTIL 4 PM EST FRIDAY FOR LHZ345>349.
LM...SMALL CRAFT ADVISORY UNTIL 4 PM EST FRIDAY FOR LMZ323-341-342-
344-345.
LS...NONE.
&&
$$
UPDATE...LAWRENCE
SYNOPSIS...TJL
SHORT TERM...MSB
LONG TERM...JPB
AVIATION...LAWRENCE
MARINE...MSB/LAWRENCE
AREA FORECAST DISCUSSION
NWS DULUTH MN
1142 PM CST THU NOV 29 2012
.UPDATE...
WE`VE UPDATED GRIDS TO INCREASE POPS ACROSS THE FAR NORTH WHERE
LIGHT SNOW WAS DEVELOPING. KCDD WAS DOWN TO 1.75SM IN SNOW AND SNOW
WAS LOCATED UPSTREAM AT KFGN/KBDE/KRRT. HIGH RES AND MODELS
INDICATE THE SNOW WILL LIFT NORTH LATE TONIGHT.
A FEW BANDS OF SNOW HAVE ALSO DEVELOPED OVER LAKE SUPERIOR AND
WERE MOVING UP THE SHORE. WE STILL EXPECT LAKE EFFECT SNOW TO
INCREASE IN COVERAGE UP THE SHORE OVERNIGHT...AS LOW LEVEL WINDS
VEER.
WE HAVE NOT SEEN ANY PRECIP YET OUTSIDE OF THE LES AND THE SNOW
ACROSS THE FAR NORTH. WE LEFT THE MENTION OF FREEZING DRIZZLE IN
THE FORECAST...ESPECIALLY LATE.
&&
.AVIATION...06Z TAFS
MVFR/IFR CONDITIONS COVERED MOST OF THE NORTHLAND...AND THAT WILL
CONTINUE AS THERE WILL BE PLENTY OF LOW LEVEL MOISTURE PRESENT
THROUGH THE PERIOD. LIGHT SNOW WAS AFFECTING THE BORDER REGION
LATE THIS EVENING...WITH SOME LAKE EFFECT SNOW AS WELL ALONG THE
NORTH SHORE. IFR VSBYS WILL BE POSSIBLE OVERNIGHT AT THE KINL TAF.
SOME FREEZING DRIZZLE WILL ALSO REMAIN A THREAT AS A WEAK
SHORTWAVE MOVES THROUGH THE REGION. THERE HAS NOT BEEN ANY REPORTS
YET...AND IT LOOKS LIKE COVERAGE WILL BE LIMITED. WE LEFT THE
MENTION IN KDLH/KHYR/KBRD/KHIB TAFS AS THERE ARE NOT STRONG ENOUGH
REASONS TO PULL IT YET.
&&
.PREV DISCUSSION... /ISSUED 556 PM CST THU NOV 29 2012/
UPDATE...
VERY LIGHT SNOW/FLURRIES WERE FALLING IN THE DULUTH AREA DUE TO
NORTHEAST WINDS DOWN LAKE SUPERIOR.
WE`VE RECEIVED A COUPLE SHIP REPORTS OF WATER TEMPERATURES OF
5C...AND BOTH THE RUC AND NAM SHOW 850MB TEMPS FROM -12C TO -5C
FROM GRAND PORTAGE TO THE TWIN PORTS. BUFR SOUNDINGS INDICATE
INVERSION LEVELS ARE RATHER LOW. WE INCREASED POPS A BIT
TONIGHT...MAINLY ALONG THE NORTH SHORE...AND BEEFED UP THE MENTION
OF FREEZING DRIZZLE AS WELL.
LOW LEVEL FLOW IS FORECAST TO VEER THROUGH THE EVENING TO MORE
E-SE...SHIFTING THE FOCUS FOR LES TO THE NORTH SHORE FROM THE TWIN
PORTS. WE DON`T EXPECT SIGNIFICANT ACCUMULATION TO OCCUR AROUND
KDLH AS THE LOWER DELTA-T`S AND INVERSION LEVELS ARE NOT THAT
FAVORABLE. THINGS DO COME TOGETHER MORE ALONG THE NORTH
SHORE...ESPECIALLY NORTH AND EAST OF SILVER BAY FROM LATE EVENING
ON. SOME SNOW ACCUMULATION WILL BE POSSIBLE UP THERE...AND WE`LL
HAVE 1-3 INCH AMOUNTS...WITH SOME LOCALIZED HIGHER AMOUNTS. WE`LL
MONITOR THE NORTH SHORE CLOSELY FOR HIGHER SNOW AMOUNTS.
FORECAST SOUNDINGS LOOK FAVORABLE FOR FREEZING DRIZZLE OVER THE
SOUTHERN HALF/TWO THIRDS OF THE CWA OVERNIGHT...THOUGH
PRECIPITATION AMOUNTS DO LOOK TO BE LIMITED. HOWEVER...IT ONLY
TAKES A LITTLE FREEZING PRECIPITATION TO GET SOME SLICK ROADS.
AVIATION...00Z TAFS
IFR AND MVFR CEILINGS COVERED MOST OF THE NORTHLAND THIS
EVENING...WITH SOME VFR CONDITIONS IN THE FAR NORTH/NORTHEAST. WE
EXPECT CEILINGS TO LOWER ALL AREAS OVERNIGHT...WITH MOST
EXPERIENCING IFR CONDITIONS BY 12Z. WAA AND A WEAK SHORTWAVE WILL
COMBINE TO BRING THE THREAT FOR LIGHT PRECIPITATION OVERNIGHT.
FORECAST SOUNDINGS LOOK FAVORABLE FOR FREEZING DRIZZLE AS THERE IS
A DRY LAYER PRESENT AND THE MOIST LAYER IS MOSTLY WARMER THAN
-10C. WE DID ADD FREEZING DRIZZLE TO THE KDLH/KHIB/KHYR TAFS
TONIGHT. FOG WILL DEVELOP OVERNIGHT INTO FRIDAY AS WELL WITH
INCREASING MOISTURE.
PREV DISCUSSION... /ISSUED 256 PM CST THU NOV 29 2012/
SHORT TERM...TONIGHT THROUGH FRIDAY NIGHT
THE MAIN CONCERN FOR THE SHORT TERM PERIOD WILL BE PRECIPITATION
TYPE ISSUES INTO FRIDAY. AREA SOUNDINGS AND BUFKIT PROFILES DEPICT
SOME FREEZING DRIZZLE ESPECIALLY FOR THE SOUTHERN HALF OF THE
FORECAST AREA. ANY FREEZING DRIZZLE THAT FALLS WILL BE VERY LIGHT
AND SPOTTY. ANOTHER CONCERN WILL BE FOR LAKE EFFECT SNOW AS WINDS
WILL BECOME MORE EASTERLY TONIGHT. TEMPERATURE PROFILES FAVOR ALL
SNOW FOR THE NORTH SHORE WHERE SNOW ACCUMULATIONS COULD REACH AROUND
AN INCH TONIGHT. THE LAKE EFFECT SNOW SHOWERS WILL DIMINISH AND SHIFT
INTO THE ARROWHEAD ONCE WINDS BECOME SOUTHEASTERLY EARLY FRIDAY. A
WEAK SHORTWAVE APPROACHING FROM THE WEST WILL CONTINUE TO BRING A
SLIGHT CHANCE OF LIGHT SNOW SHOWERS AND PATCHY FREEZING DRIZZLE OVER
THE NORTHERN HALF OF THE FORECAST AREA THROUGH FRIDAY NIGHT.
TEMPERATURES ON FRIDAY WILL RISE TO THE MIDDLE 30S OVER THE FAR
SOUTHERN PORTIONS OF THE AREA ENDING THE FREEZING DRIZZLE THREAT.
WARM AIR ADVECTION FROM THE SOUTH OVER THE SNOW COVERED GROUND WILL
LEAD TO AREAS OF FOG OVER MOST OF THE FORECAST AREA ON FRIDAY NIGHT.
LONG TERM...SATURDAY THROUGH TUESDAY...
MID LVL RIDGE BREAKS DOWN ALONG PACNW COAST ALLOWING A RAPID INFLUX
OF MILD AIR TO SPREAD INLAND TO NRN CONUS FROM SATURDAY INTO MONDAY.
A WEAK SYSTEM...SFC/ALOFT...WILL PROGRESS FROM THE NRN PLAINS INTO
THE GT LAKES SATURDAY WITH LIGHT PRECIP EXPECTED. MAY SEE SOME
RESIDUAL FZRA/SN OVER INTERIOR OF THE ARROWHEAD SATURDAY AS
RETREATING COLD DOME IS TOPPED BY WARM AIR ADVECTION. WEAK COLD
FRONT MAY ALLOW BRIEF TRANSITION TO RA/SN OVER NRN TIER OF MN ZONES
EARLY SUNDAY. NEXT SYSTEM HAS MUCH STRONGER DYNAMICS ALOFT AND WILL
INTENSIFY AS IT MOVES FROM NODAK INTO WRN ONTARIO MONDAY. SIGNIFICANT
PUSH OF WARM AIR WILL KEEP PTYPE IN THE LIQUID FORM MONDAY BEFORE
CHANGING TO SNOW MONDAY NIGHT OVER MN ZONES. ALTHOUGH THERE WILL BE
SIGNIFICANT COLD AIR ADVECTION BEHIND THE SYSTEM TUESDAY...THE
PROGRESSIVE NATURE OF THE FLOW ALOFT APPEARS TO MAKE A CASE FOR A
RETURN TO ANOMALOUS WARMTH FOR LATE IN THE WEEK.
&&
.POINT TEMPS/POPS...
DLH 21 32 29 39 / 40 30 20 50
INL 12 29 26 37 / 60 30 20 40
BRD 23 33 29 41 / 20 20 10 40
HYR 22 33 31 43 / 20 20 10 50
ASX 23 32 30 43 / 30 20 20 40
&&
.DLH WATCHES/WARNINGS/ADVISORIES...
MN...NONE.
WI...NONE.
LS...SMALL CRAFT ADVISORY UNTIL 6 PM CST FRIDAY FOR LSZ121-140>148.
&&
$$
SHORT TERM...MELDE
LONG TERM....CANNON
AVIATION...MELDE
AREA FORECAST DISCUSSION
NWS ST LOUIS MO
351 AM CST FRI NOV 30 2012
.SHORT TERM...
ISSUED AT 350 AM CST FRI NOV 30 2012
(TODAY)
UNSEASONABLY MILD LATE AUTUMN NIGHT SHOULD BE A LEAD-IN TO AN
UNSEASONABLY WARM LATE NOVEMBER DAY FOR THE CWA...AND CLOUDS WILL BE
THE DETERIMINING FACTOR ON HOW WARM WE WILL GET THIS AFTERNOON.
MODELS ARE FORECASTING THE INCREASE IN LOW LEVEL RH TO BEGIN
TODAY...AND INDEED THE LOW CLOUD SATELLITE ENHANCEMENT HAS INDICATED
SOME CLOUDS FORMING OVER E OK AND W CENTRAL/NW AR OVER THE PAST FEW
HOURS...WITH A FEW CLOUDS ALSO JUST BEGINNING TO SHOW UP SE OF A
VIH-FAM LINE. HOWEVER... BELIEVE THIS INITIAL SURGE WILL BE FAIRLY
SHALLOW AND MAY HAVE A DIFFICULT TIME MAINTAINING A PERSISTENT CLOUD
DECK. RAP DATA SUGGESTS THAT THE BEST LOW LEVEL MOISTURE RETURN
THROUGH TODAY WILL REMAIN TO OUR S...BOTTLED UP BY THE ARKANSAS
PORTION OF THE OZARK PLATEAU/BOSTON MOUNTAINS. BASED ON THE THINKING
THAT THERE SHOULD BE A FAIR AMOUNT OF SUNSHINE TODAY HAVE ONCE AGAIN
TRENDED TO THE WARMER MET NUMBERS...WITH HIGHS RANGING FROM AROUND
60 IN FAR N/E COUNTIES OF THE CWA TO THE MIDDLE 60S ALONG AND S OF
THE I-70 CORRIDOR IN MO.
TRUETT
&&
.LONG TERM...
ISSUED AT 350 AM CST FRI NOV 30 2012
(TONIGHT THROUGH SUNDAY NIGHT)
A LOT TO DEAL WITH IN THE SHORT TERM...AS FORECAST AREA TO SEE WELL
ABOVE NORMAL TEMPERATURES THROUGH THE PERIOD...DESPITE A BIT MORE
CLOUDS OVER THE REGION THROUGH THE WEEKEND.
FOR TONIGHT...WEAK WARM FRONT TO LIFT NORTH OF FORECAST AREA...SO
ANY PATCHY FOG THAT MAY FORM OVER NORTHERN PORTIONS OF FORECAST
EARLY ON...WILL IMPROVE AS WINDS PICKUP FROM THE SOUTH.
OTHERWISE...LOWS WILL ONLY BE IN THE 40S.
THEN ON SATURDAY LOW LEVEL MOISTURE WILL CONTINUE TO BE ON THE
INCREASE AHEAD OF COLD FRONT THAT WILL SLIDE THROUGH AREA SATURDAY
NIGHT...BEFORE WEAKENING/WASHING OUT ON SUNDAY. SOME CONCERN ABOUT
STRATUS ADVECTING NORTH INTO SOUTHERN PORTIONS OF FORECAST AREA
SATURDAY MORNING AHEAD OF SYSTEM...BUT BUFKIT SOUNDINGS HAVE BRIEF
LOW CIGS WITH STRATUS THEN LIFT BY MID MORNING. SO FOR NOW HAVE NOT
ADDED MENTION OF DRIZZLE IN THIS AREA. OTHERWISE...WILL SEE SOME
LIGHT RAIN DEVELOP OVER NORTHERN PORTIONS OF FORECAST AREA AHEAD OF
COLD FRONT SATURDAY AFTERNOON. AMOUNTS WITH THIS SYSTEM WILL BE
RATHER LIGHT...SO JUST WENT WITH LOW CHANCE POPS AND LIGHT RAIN. AS
FOR TEMPS...WITH MORE CLOUDS FORECAST OVER THE REGION...LOWERED HIGH
TEMPS A FEW DEGREES...INTO THE LOW TO MID 60S.
BETTER CHANCES OF LIGHT RAIN SATURDAY NIGHT...BUT STILL NOT A LOT OF
QPF WITH FRONTAL BOUNDARY...SO KEPT LOW CHANCE POPS FOR AREAS ALONG
AND NORTH OF A STEELVILLE MO TO SPARTA IL LINE. ANOTHER MILD NIGHT
IN STORE WITH LOWS ONLY IN THE LOW TO MID 50S.
ON SUNDAY THE FRONTAL BOUNDARY WILL WASHOUT ALONG I-44 CORRIDOR...SO
SOME LINGERING LIGHT RAIN POSSIBLE ALONG AND SOUTH OF THIS AREA
DURING THE DAY...WHICH COULD LINGER INTO SUNDAY NIGHT...BUT
CONFIDENCE IS LOW...SO KEPT MENTION OUT FOR NOW. AS FOR
TEMPS...CLOUDS TO THIN OUT FOR NORTHERN PORTIONS OF FORECAST AREA
AND WINDS TO PICKUP FROM THE SOUTHWEST. SO WILL SEE NEAR RECORD
HIGHS WITH TEMPS IN THE 65 TO 70 DEGREE RANGE. MILD TEMPS TO PERSIST
SUNDAY NIGHT...WILL LOWS IN THE MID TO UPPER 50S.
(MONDAY THROUGH THURSDAY)
BY MONDAY...A MORE VIGOROUS SYSTEM TO APPROACH THE REGION WITH A
COLD FRONT SLIDING THROUGH DURING THE AFTERNOON AND EVENING HOURS.
SOME DECENT INSTABILITY...LIFT AND LOW LEVEL MOISTURE...SO SHOULD
SEE SHOWERS AND SOME THUNDERSTORMS. HIGHS ON MONDAY WILL REMAIN WELL
ABOVE NORMAL IN THE UPPER 60S TO LOW 70S...NEAR RECORD HIGHS FOR A
NUMBER OF LOCATIONS. LOWS MONDAY NIGHT WILL BE IN THE LOW 40S FAR
NORTH TO THE LOW 50S FAR SOUTHEAST.
BY TUESDAY...SHOWERS TO TAPER OFF AND COLDER AIR TO FILTER IN.
HOWEVER...NOT A LOT OF CAA WITH SYSTEM...SO TEMPS WILL STILL BE A
BIT ABOVE NORMAL...IN THE LOW 50S NORTH TO THE UPPER 50S SOUTH.
BEYOND THAT...SURFACE RIDGE TO BUILD IN WITH NEAR NORMAL TEMPS FOR
THE REST OF THE FORECAST PERIOD.
BYRD
&&
.AVIATION...
ISSUED AT 1107 PM CST THU NOV 29 2012
WARM FRONT EXTENDS EAST FROM A WEAK AREA OF LOW PRESSURE IN
EASTERN NEBRASKA THROUGH SOUTHERN IOWA AND INTO CENTRAL ILLINOIS.
AREA REMAINS IN WARM SECTOR WITH SOUTHERLY WINDS OF 5 TO 10KTS.
CLOUD COVER IS LIMITED TO AREAS OF CIRRUS. LOW LEVEL WIND SHEAR
CONTINUES AS WINDS RAPIDLY INCREASE TO 45KTS AT 1500FT. MODELS
DEPICT WIND DECREASING TOMORROW MORNING AS SYSTEM MOVES NORTH OF
THE AREA AND PRESSURE GRADIENT RELAXES. STEADY SOUTHERLY FLOW WILL
EVENTUALLY LEAD TO MOISTURE...CURRENTLY IN SOUTHERN
TEXAS...ADVECTING NORTH/NORTHEAST INTO THE REGION FRIDAY EVENING
AND INTO THE OVERNIGHT HOURS.
SPECIFICS FOR KSTL...
VFR CONDITIONS WILL CONTINUE. LLWS EXPECTED THROUGH FRIDAY MORNING
GIVEN 45KT SOUTHWEST WIND AT 1500FT. CLOUD COVER AROUND 5KFT WILL
BUILD ACROSS THE TERMINAL LATE FRIDAY EVENING OR EARLY SATURDAY
MORNING.
CVKING
&&
.CLIMATE...
ISSUED AT 504 PM CST WED NOV 28 2012
ABOVE NORMAL TEMPERATURES ARE FORECAST THIS WEEKEND. HERE ARE THE
RECORD HIGH AND HIGH MINIMUM TEMPERATURES FOR THE FIRST THREE DAYS
OF DECEMBER FOR THE CITIES OF ST. LOUIS...COLUMBIA...AND QUINCY.
RECORD HIGH TEMPERATURES...
ST. LOUIS COLUMBIA QUINCY
SATURDAY 12/1 73F (1970) 68F (1982) 67F (1913)
SUNDAY 12/2 74F (1982) 72F (1917) 67F (1982)
MONDAY 12/3 76F (1970) 72F (1998) 71F (1970)
RECORD HIGH MINIMUM TEMPERATURES...
ST. LOUIS COLUMBIA QUINCY
SATURDAY 12/1 53F (1980) 53F (1921) 52 (1913)
SUNDAY 12/2 63F (1982) 59F (1982) 59 (1982)
MONDAY 12/3 62F (1998) 58F (1998) 59 (1998)
&&
.LSX WATCHES/WARNINGS/ADVISORIES...
MO...NONE.
IL...NONE.
&&
$$
WFO LSX
AREA FORECAST DISCUSSION...UPDATED
NWS NORTH PLATTE NE
1147 PM CST THU NOV 29 2012
.UPDATE...
.AVIATION...
A CLOSER LOOK AT THE LIFR CIGS ACROSS SD AND RAP MODEL DATA
SUGGESTS THESE CIGS COULD BACK INTO KONL AND PERHAPS APPROACH
KVTN FOR A FEW HOURS EARLY THIS MORNING. ITS TOO CLOSE TO CALL
ATTM BUT THIS AREA WILL BE CLOSELY MONITORED OVERNIGHT AS
SATELLITE INDICATES A MORE SOUTHERLY PROGRESSION DEVELOPING.
&&
.PREV DISCUSSION... /ISSUED 1126 PM CST THU NOV 29 2012/
UPDATE...
AVIATION...
VFR IS EXPECTED ALL AREAS OVERNIGHT THROUGH FRIDAY EVENING.
AN AREA OF LIFR CIGS ALONG THE MISSOURI RIVER IN SD WILL MOVE
SOUTHEAST OVERNIGHT SQUIRTING THE NEB BORDER. OTHERWISE SCT-BKN
HIGH LEVEL CLOUDINESS WILL CONTINUE THROUGH FRIDAY EVENING.
PREV DISCUSSION... /ISSUED 500 PM CST THU NOV 29 2012/
UPDATE...
AVIATION...
VFR IS EXPECTED ALL AREAS OVERNIGHT THROUGH FRIDAY.
AN ARCTIC FRONT ACROSS CNTL SD THIS EVENING WILL DROP SOUTH AND
INTO NCNTL NEB OVERNIGHT. THE FRONT IS NOT EXPECTED TO PRODUCE ANY FLIGHT
LIMITATIONS AT THIS TIME. THE RAP MODEL...ETAL SUGGEST STRATUS
WILL FROM ALONG AND NORTH OF THE MISSOURI RIVER...EAST OF THE FCST
AREA.
OTHERWISE SCT-BKN HIGH LEVEL CLOUDINESS WILL CONTINUE THROUGH
FRIDAY.
PREV DISCUSSION... /ISSUED 305 PM CST THU NOV 29 2012/
SYNOPSIS...
12Z H5 HAND ANALYSIS FROM THIS MORNING WAS INDICATING BROAD ZONAL
FLOW EXTENDING ACROSS THE CONUS. LOW PRESSURE WAS PRESENT ACROSS
NORTH CENTRAL CANADA...NRN QUEBEC...AND OFF THE COAST OF BRITISH
COLUMBIA. FURTHER SOUTH ACROSS THE CONUS...STRONG MID AND UPPER
LEVEL FLOW...HAS SPREAD ABUNDANT MID AND HIGH LEVEL CLOUDINESS
ACROSS THE WESTERN THIRD OF THE CONUS TDY. SCATTERED TO BROKEN UPPER
LEVEL CLOUDINESS WHICH WAS PRESENT ACROSS CENTRAL AND NORTHERN
NEBRASKA EARLIER THIS MORNING...AND HAS SHIFTED EAST BY MIDDAY.
UNDER SUNNY SKIES...TEMPERATURES AS OF 2 PM CST...RANGED FROM 46 AT
AINSWORTH...TO 70 AT IMPERIAL.
DISCUSSION...
SHORT RANGE...TONIGHT THROUGH SUNDAY NIGHT...FORECASTING CHALLENGE
WILL BE TEMPERATURES AND THE IMPACT OF CLOUD COVER AND SNOW COVER ON
THEM.
FOR TONIGHT...A WEAK DISTURBANCE WILL TRACK ACROSS THE
DAKOTAS...BACKING A WEAK COOL FRONT INTO NORTHERN NEBRASKA TONIGHT.
THE SRN SURGE OF THE FRONT IS EXPECTED TO REACH THE CENTRAL FORECAST
AREA OVERNIGHT...LIFTING NORTH AS A WARM FRONT ON FRIDAY. LOWS
TONIGHT WILL BE COOLEST IN THE PLATTE RIVER VALLEY WITH LIGHT
WESTERLY WINDS...AND ACROSS THE SNOWFIELD IN THE NRN CWA...WHICH
WILL ENCOMPASS NORTHERN SHERIDAN...AND A LARGE PORTION OF CHERRY
COUNTY.
ON FRIDAY...LIGHT SRLY WINDS WILL DEVELOP AS A WARM FRONT LIFTS
NORTHEAST OF THE FORECAST AREA. WARMER H85 AIR WILL PUSH INTO
NORTHERN NEBRASKA FRIDAY AFTERNOON...RESULTING IN HIGHS IN THE
MIDDLE 50S. SIDED WITH THE COOLER MET GUIDANCE...ESPECIALLY OVER
CHERRY AND SHERIDAN COUNTY...WHERE SNOW COVER IS EXPECTED TO PERSIST
AT LEAST THROUGH MIDDAY FRIDAY. ELSEWHERE...HIGHS SHOULD TOP OUT IN
THE UPPER 50S AND LOWER 60S UNDER SUNNY SKIES. HIGH LEVEL CLOUD
COVER WILL BE ON THE INCREASE FRIDAY NIGHT...AS AN UPPER LEVEL JET
STREAK CROSSES THE NORTHERN ROCKIES AND NORTHERN PLAINS. WITH DECENT
AGREEMENT BETWEEN THE GFS AND NAM SOLNS WITH RESPECT TO THE DEGREE
OF UPPER LEVEL MOISTURE...OPTED TO INCREASE CLOUD COVER FRIDAY NIGHT
AND BOOSTED MIN TEMPS ACCORDINGLY WITH MOSTLY CLOUDY SKIES EXPECTED.
SATURDAY AND SUNDAY...SKIES WILL CLEAR SATURDAY MORNING AS THE
BEFORE MENTIONED JET STREAK PUSHES INTO THE UPPER MIDWEST. AT THE
SAME TIME...A SURFACE TROUGH OF LOW PRESSURE WILL TRACK ACROSS THE
DAKOTAS...SHIFTING WINDS TO THE WEST SATURDAY AFTERNOON. THE
COMBINATION OF FULL SUN...WESTERLY WINDS AND H85 TEMPS IN THE LOWER
TEENS C...WILL RESULT IN HIGHS IN THE MID 60S. SOME TEMPS MAY TOP OUT
IN THE LOWER 70S IN THE FAR SOUTHWEST AS H85 TEMPS APPROACH THE
MIDDLE TEENS C. ON SUNDAY...A SURFACE TROUGH OF LOW PRESSURE WILL
DEEPEN ACROSS THE PANHANDLE...SHIFTING WINDS FROM THE WEST TO THE
SOUTH AND INCREASING THEM TO 10 TO 20 MPH SUNDAY AFTERNOON. BASED ON
H85 TEMPS AND DECENT MIXING POTENTIAL...ANOTHER DAY OF HIGHS IN THE
60S LOOKS ON TRACK.
LONG RANGE...MONDAY THROUGH THURSDAY...A TANDEM OF COLD FRONTS WILL
TRACK ACROSS THE REGION NEXT WEEK...THE FIRST ON MONDAY...WHICH WILL
BE PRIMARILY A WIND PRODUCER...AND A SECOND ON WEDNESDAY NIGHT.
HIGHS NEXT WEEK WILL BE COOLER THAN THIS WEEKENDS READINGS...WITH
HIGHS IN THE 50S EXPECTED. ARCTIC AIR MAY BEGIN TO APPROACH THE
NORTHERN PLAINS ON THURSDAY...WITH THE GFS PUSHING AN ARCTIC FRONT
THROUGH WRN AND NORTH CENTRAL NEBRASKA THURSDAY...WHILE THE ECMWF
SOLN DELAYS THIS A COUPLE OF DAYS. DECIDED TO KEEP TEMPS WARM AND
DELAY ANY POTENTIAL ARCTIC FROPA TIL AFTER DAY 7 BASED ON THE SLOWER
ECMWF SOLN. DRY CONDS WILL CONTINUE INTO THE EXTENDED AS WELL.
AVIATION...
FOR THE 18Z TAF ISSUANCE...VISUAL FLIGHT RULES THROUGH MIDDAY FRIDAY
OVER WESTERN AND NORTH CENTRAL NEBRASKA WITH PASSING HIGH CLOUDS AOA
20K FT MOVING IN THE WESTERLIES OVER THE AREA. GENERALLY WESTERLY
FLOW WOULD BE EXPECTED AT THE SURFACE FOR AREA TERMINALS...WHICH
SHOULD REMAIN AOB 12KTS THROUGH AFTERNOON...THEN GOING LIGHT AND
VARIABLE THEREAFTER. ONE EXCEPTION BEING ACROSS THE FAR WESTERN
SANDHILLS...WHERE WIND GUSTS TO 20KTS OR HIGHER WILL CONTINUE.
RECENT METARS OVER THE WESTERN PANHANDLE REGION ACTUALLY INDICATE
MUCH STRONGER WIND SPEEDS...WHICH NEAR TERM MODEL GUIDANCE HINTS AT
SOME OF THIS MOMENTUM SPREADING EAST...TO POSSIBLY A KOGA TO KIEN
LINE....WHICH SEEMS PLAUSIBLE. REGARDLESS...WIND SPEEDS WOULD
DECREASE SHORTLY AFTER SUNDOWN.
FIRE WEATHER...
NEAR CRITICAL FIRE WEATHER CONDITIONS TO CONTINUE THROUGH LATE
AFTERNOON TODAY ACROSS SOUTHWEST NEBRASKA AND THE SOUTHEASTERN
PANHANDLE...WITH SIMILAR CONDITIONS EXPECTED OVER THE SAME AREA
TOMORROW. ABNORMALLY WARM...DRY AIRMASS HAS SETTLED ACROSS THE
REGION...WITH SURFACE RELATIVE HUMIDITY FALLING BELOW 15 PERCENT
OVER MUCH OF FIRE ZONE 210...AND OVER SOUTHERN PORTIONS OF 204.
EXPECTING THIS TREND TO CONTINUE THROUGH LATE AFTERNOON TODAY...WITH
SOME LOCATIONS POSSIBLY RECORDING MINIMUM RH OF LESS THAN 10 PERCENT
/MAINLY SOUTH OF INTERSTATE 80/. AFTER SUNDOWN...RH VALUES WILL
INCREASE STEADILY WITH THE COOLING TEMPERATURES. FOR TOMORROW...A
WEAK FRONTAL BOUNDARY WILL ALLOW FOR SLIGHTLY COOLER
TEMPERATURES...BUT WITH THE DRY AIRMASS...RH WILL ONCE AGAIN FALL TO
20 PERCENT OR LESS. ELSEWHERE...RESIDUAL MOISTURE FROM SNOWFALL
LAST WEEK WILL HELP KEEP MINIMUM RH VALUES AT OR ABOVE 25 PERCENT.
NOW ONTO THE WIND COMPONENT...A CRAIG HIGH HAS DEVELOPED /FAVORABLE
PATTERN FOR GUSTY WESTERLY WIND OVER THE PANHANDLE REGION/...WIND
GUSTS TO 25 MPH MAY BE POSSIBLE ACROSS THE FAR EASTERN PANHANDLE
THROUGH LATE AFTERNOON TODAY...BUT THE STRONGEST WIND SPEEDS WILL
REMAIN FURTHER WEST /WESTERN AND CENTRAL PANHANDLE INTO WYOMING/.
BREEZY WIND SPEEDS CAN BE EXPECTED ONCE AGAIN FOR FRIDAY...BUT AGAIN
THE STRONGER WIND GUSTS /ALBEIT 25 MPH OR LESS/ WILL BE OUT OVER THE
EASTERN PANHANDLE...WITH LIGHTER WIND SPEEDS /15 MPH OR LESS/ FOR ALL
OTHER AREAS.
GIVEN THE MARGINALITY OF THE FIRE WEATHER CONDITIONS...NO FIRE
HEADLINES ARE ANTICIPATED TODAY OR TOMORROW...BUT LOCALIZED RFW
CONDITIONS MAY EXIST FOR AN HOUR OR TWO LATE THIS AFTERNOON AND
POSSIBLY LATE TOMORROW FOR PORTIONS OF FIRE ZONE 204 AND 210.
&&
.LBF WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
SHORT TERM/EXTENDED...MASEK
AVIATION...CDC
AREA FORECAST DISCUSSION...UPDATED
NWS NORTH PLATTE NE
1126 PM CST THU NOV 29 2012
.UPDATE...
.AVIATION...
VFR IS EXPECTED ALL AREAS OVERNIGHT THROUGH FRIDAY EVENING.
AN AREA OF LIFR CIGS ALONG THE MISSOURI RIVER IN SD WILL MOVE
SOUTHEAST OVERNIGHT SQUIRTING THE NEB BORDER. OTHERWISE SCT-BKN
HIGH LEVEL CLOUDINESS WILL CONTINUE THROUGH FRIDAY EVENING.
&&
.PREV DISCUSSION... /ISSUED 500 PM CST THU NOV 29 2012/
UPDATE...
AVIATION...
VFR IS EXPECTED ALL AREAS OVERNIGHT THROUGH FRIDAY.
AN ARCTIC FRONT ACROSS CNTL SD THIS EVENING WILL DROP SOUTH AND
INTO NCNTL NEB OVERNIGHT. THE FRONT IS NOT EXPECTED TO PRODUCE ANY FLIGHT
LIMITATIONS AT THIS TIME. THE RAP MODEL...ETAL SUGGEST STRATUS
WILL FROM ALONG AND NORTH OF THE MISSOURI RIVER...EAST OF THE FCST
AREA.
OTHERWISE SCT-BKN HIGH LEVEL CLOUDINESS WILL CONTINUE THROUGH
FRIDAY.
PREV DISCUSSION... /ISSUED 305 PM CST THU NOV 29 2012/
SYNOPSIS...
12Z H5 HAND ANALYSIS FROM THIS MORNING WAS INDICATING BROAD ZONAL
FLOW EXTENDING ACROSS THE CONUS. LOW PRESSURE WAS PRESENT ACROSS
NORTH CENTRAL CANADA...NRN QUEBEC...AND OFF THE COAST OF BRITISH
COLUMBIA. FURTHER SOUTH ACROSS THE CONUS...STRONG MID AND UPPER
LEVEL FLOW...HAS SPREAD ABUNDANT MID AND HIGH LEVEL CLOUDINESS
ACROSS THE WESTERN THIRD OF THE CONUS TDY. SCATTERED TO BROKEN UPPER
LEVEL CLOUDINESS WHICH WAS PRESENT ACROSS CENTRAL AND NORTHERN
NEBRASKA EARLIER THIS MORNING...AND HAS SHIFTED EAST BY MIDDAY.
UNDER SUNNY SKIES...TEMPERATURES AS OF 2 PM CST...RANGED FROM 46 AT
AINSWORTH...TO 70 AT IMPERIAL.
DISCUSSION...
SHORT RANGE...TONIGHT THROUGH SUNDAY NIGHT...FORECASTING CHALLENGE
WILL BE TEMPERATURES AND THE IMPACT OF CLOUD COVER AND SNOW COVER ON
THEM.
FOR TONIGHT...A WEAK DISTURBANCE WILL TRACK ACROSS THE
DAKOTAS...BACKING A WEAK COOL FRONT INTO NORTHERN NEBRASKA TONIGHT.
THE SRN SURGE OF THE FRONT IS EXPECTED TO REACH THE CENTRAL FORECAST
AREA OVERNIGHT...LIFTING NORTH AS A WARM FRONT ON FRIDAY. LOWS
TONIGHT WILL BE COOLEST IN THE PLATTE RIVER VALLEY WITH LIGHT
WESTERLY WINDS...AND ACROSS THE SNOWFIELD IN THE NRN CWA...WHICH
WILL ENCOMPASS NORTHERN SHERIDAN...AND A LARGE PORTION OF CHERRY
COUNTY.
ON FRIDAY...LIGHT SRLY WINDS WILL DEVELOP AS A WARM FRONT LIFTS
NORTHEAST OF THE FORECAST AREA. WARMER H85 AIR WILL PUSH INTO
NORTHERN NEBRASKA FRIDAY AFTERNOON...RESULTING IN HIGHS IN THE
MIDDLE 50S. SIDED WITH THE COOLER MET GUIDANCE...ESPECIALLY OVER
CHERRY AND SHERIDAN COUNTY...WHERE SNOW COVER IS EXPECTED TO PERSIST
AT LEAST THROUGH MIDDAY FRIDAY. ELSEWHERE...HIGHS SHOULD TOP OUT IN
THE UPPER 50S AND LOWER 60S UNDER SUNNY SKIES. HIGH LEVEL CLOUD
COVER WILL BE ON THE INCREASE FRIDAY NIGHT...AS AN UPPER LEVEL JET
STREAK CROSSES THE NORTHERN ROCKIES AND NORTHERN PLAINS. WITH DECENT
AGREEMENT BETWEEN THE GFS AND NAM SOLNS WITH RESPECT TO THE DEGREE
OF UPPER LEVEL MOISTURE...OPTED TO INCREASE CLOUD COVER FRIDAY NIGHT
AND BOOSTED MIN TEMPS ACCORDINGLY WITH MOSTLY CLOUDY SKIES EXPECTED.
SATURDAY AND SUNDAY...SKIES WILL CLEAR SATURDAY MORNING AS THE
BEFORE MENTIONED JET STREAK PUSHES INTO THE UPPER MIDWEST. AT THE
SAME TIME...A SURFACE TROUGH OF LOW PRESSURE WILL TRACK ACROSS THE
DAKOTAS...SHIFTING WINDS TO THE WEST SATURDAY AFTERNOON. THE
COMBINATION OF FULL SUN...WESTERLY WINDS AND H85 TEMPS IN THE LOWER
TEENS C...WILL RESULT IN HIGHS IN THE MID 60S. SOME TEMPS MAY TOP OUT
IN THE LOWER 70S IN THE FAR SOUTHWEST AS H85 TEMPS APPROACH THE
MIDDLE TEENS C. ON SUNDAY...A SURFACE TROUGH OF LOW PRESSURE WILL
DEEPEN ACROSS THE PANHANDLE...SHIFTING WINDS FROM THE WEST TO THE
SOUTH AND INCREASING THEM TO 10 TO 20 MPH SUNDAY AFTERNOON. BASED ON
H85 TEMPS AND DECENT MIXING POTENTIAL...ANOTHER DAY OF HIGHS IN THE
60S LOOKS ON TRACK.
LONG RANGE...MONDAY THROUGH THURSDAY...A TANDEM OF COLD FRONTS WILL
TRACK ACROSS THE REGION NEXT WEEK...THE FIRST ON MONDAY...WHICH WILL
BE PRIMARILY A WIND PRODUCER...AND A SECOND ON WEDNESDAY NIGHT.
HIGHS NEXT WEEK WILL BE COOLER THAN THIS WEEKENDS READINGS...WITH
HIGHS IN THE 50S EXPECTED. ARCTIC AIR MAY BEGIN TO APPROACH THE
NORTHERN PLAINS ON THURSDAY...WITH THE GFS PUSHING AN ARCTIC FRONT
THROUGH WRN AND NORTH CENTRAL NEBRASKA THURSDAY...WHILE THE ECMWF
SOLN DELAYS THIS A COUPLE OF DAYS. DECIDED TO KEEP TEMPS WARM AND
DELAY ANY POTENTIAL ARCTIC FROPA TIL AFTER DAY 7 BASED ON THE SLOWER
ECMWF SOLN. DRY CONDS WILL CONTINUE INTO THE EXTENDED AS WELL.
AVIATION...
FOR THE 18Z TAF ISSUANCE...VISUAL FLIGHT RULES THROUGH MIDDAY FRIDAY
OVER WESTERN AND NORTH CENTRAL NEBRASKA WITH PASSING HIGH CLOUDS AOA
20K FT MOVING IN THE WESTERLIES OVER THE AREA. GENERALLY WESTERLY
FLOW WOULD BE EXPECTED AT THE SURFACE FOR AREA TERMINALS...WHICH
SHOULD REMAIN AOB 12KTS THROUGH AFTERNOON...THEN GOING LIGHT AND
VARIABLE THEREAFTER. ONE EXCEPTION BEING ACROSS THE FAR WESTERN
SANDHILLS...WHERE WIND GUSTS TO 20KTS OR HIGHER WILL CONTINUE.
RECENT METARS OVER THE WESTERN PANHANDLE REGION ACTUALLY INDICATE
MUCH STRONGER WIND SPEEDS...WHICH NEAR TERM MODEL GUIDANCE HINTS AT
SOME OF THIS MOMENTUM SPREADING EAST...TO POSSIBLY A KOGA TO KIEN
LINE....WHICH SEEMS PLAUSIBLE. REGARDLESS...WIND SPEEDS WOULD
DECREASE SHORTLY AFTER SUNDOWN.
FIRE WEATHER...
NEAR CRITICAL FIRE WEATHER CONDITIONS TO CONTINUE THROUGH LATE
AFTERNOON TODAY ACROSS SOUTHWEST NEBRASKA AND THE SOUTHEASTERN
PANHANDLE...WITH SIMILAR CONDITIONS EXPECTED OVER THE SAME AREA
TOMORROW. ABNORMALLY WARM...DRY AIRMASS HAS SETTLED ACROSS THE
REGION...WITH SURFACE RELATIVE HUMIDITY FALLING BELOW 15 PERCENT
OVER MUCH OF FIRE ZONE 210...AND OVER SOUTHERN PORTIONS OF 204.
EXPECTING THIS TREND TO CONTINUE THROUGH LATE AFTERNOON TODAY...WITH
SOME LOCATIONS POSSIBLY RECORDING MINIMUM RH OF LESS THAN 10 PERCENT
/MAINLY SOUTH OF INTERSTATE 80/. AFTER SUNDOWN...RH VALUES WILL
INCREASE STEADILY WITH THE COOLING TEMPERATURES. FOR TOMORROW...A
WEAK FRONTAL BOUNDARY WILL ALLOW FOR SLIGHTLY COOLER
TEMPERATURES...BUT WITH THE DRY AIRMASS...RH WILL ONCE AGAIN FALL TO
20 PERCENT OR LESS. ELSEWHERE...RESIDUAL MOISTURE FROM SNOWFALL
LAST WEEK WILL HELP KEEP MINIMUM RH VALUES AT OR ABOVE 25 PERCENT.
NOW ONTO THE WIND COMPONENT...A CRAIG HIGH HAS DEVELOPED /FAVORABLE
PATTERN FOR GUSTY WESTERLY WIND OVER THE PANHANDLE REGION/...WIND
GUSTS TO 25 MPH MAY BE POSSIBLE ACROSS THE FAR EASTERN PANHANDLE
THROUGH LATE AFTERNOON TODAY...BUT THE STRONGEST WIND SPEEDS WILL
REMAIN FURTHER WEST /WESTERN AND CENTRAL PANHANDLE INTO WYOMING/.
BREEZY WIND SPEEDS CAN BE EXPECTED ONCE AGAIN FOR FRIDAY...BUT AGAIN
THE STRONGER WIND GUSTS /ALBEIT 25 MPH OR LESS/ WILL BE OUT OVER THE
EASTERN PANHANDLE...WITH LIGHTER WIND SPEEDS /15 MPH OR LESS/ FOR ALL
OTHER AREAS.
GIVEN THE MARGINALITY OF THE FIRE WEATHER CONDITIONS...NO FIRE
HEADLINES ARE ANTICIPATED TODAY OR TOMORROW...BUT LOCALIZED RFW
CONDITIONS MAY EXIST FOR AN HOUR OR TWO LATE THIS AFTERNOON AND
POSSIBLY LATE TOMORROW FOR PORTIONS OF FIRE ZONE 204 AND 210.
&&
.LBF WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
SHORT TERM/EXTENDED...MASEK
AVIATION...CDC
AREA FORECAST DISCUSSION...CORRECTED
NWS PORTLAND OR
900 PM PST THU NOV 29 2012
.SYNOPSIS...A BROAD UPPER LOW OVER THE NE PACIFIC WILL SEND A SERIES
OF FRONTS ACROSS THE PACIFIC NW THROUGH THE WEEKEND. SHOWERS WILL
PERSIST TONIGHT IN THE WAKE OF A COLD FRONT..AND INCREASE FRIDAY
MORNING AS THE NEXT SYSTEM APPROACHES. THE NEXT FRONT WILL MOVE
THROUGH FRIDAY NIGHT AND SATURDAY MORNING. SNOW LEVELS WILL LOWER TO
PASS LEVEL WITH THIS SYSTEM. ANOTHER FRONT IS EXPECTED SATURDAY NIGHT
AND SUNDAY MORNING.
&&
.SHORT TERM...A MASSIVE TROUGH OVER THE EASTERN PACIFIC WILL CONTINUE
TO SPIN EMBEDDED SHORTWAVE TROUGHS ACROSS THE REGION THROUGH THE
WEEKEND. WE ARE CURRENTLY NEAR THE LEFT EXIT REGION OF AN UPPER LEVEL
JET...WHICH HAS LIKELY AIDED IN THE DEVELOPMENT OF A QUASI BAROCLINIC
LEAF OVER WEST CENTRAL OREGON. PER RADAR IMAGERY...WIDESPREAD RAIN
SHOWERS ARE SPREADING NORTHEASTWARD ACROSS THE AREA THIS EVENING.
ONCE THIS WAVE PASSES...EXPECT AT LEAST A TEMPORARY LULL IN PRECIP
ACROSS THE VALLEY DURING THE EARLY MORNING HOURS. SATELLITE
EXTRAPOLATION AND THE HRRR SUPPORT THIS GENERAL IDEA.
ANOTHER EMBEDDED VORT MAX CURRENTLY APPROACHING 130W WILL BE LAPPING
ON OUR DOORSTEP EARLY FRIDAY MORNING...WHICH SHOULD RESULT IN ANOTHER
UPTICK IN SHOWER ACTIVITY...PARTICULARLY ALONG THE COAST.
A THIRD VORT MAX CURRENTLY NEAR 50N AND 150W WILL PUSH ASHORE FRIDAY
EVENING RESULTING IN A BAND OF HEAVIER RAIN THAT WILL DROP
SOUTHEASTWARD ACROSS THE CWA FRIDAY EVENING INTO FRIDAY NIGHT. THE
COAST RANGE WILL LIKELY RECEIVE A COUPLE INCHES OF RAIN FROM THIS
EVENT...BUT AT THIS TIME...MAIN STEM RIVER FLOODING IS NOT
ANTICIPATED.
FINALLY...THE MODELS ARE IN RELATIVELY GOOD AGREEMENT THAT ANOTHER
VORT MAX AND SHORTWAVE TROUGH CURRENTLY NEAR THE ALEUTIAN ISLANDS
WILL SWING INTO THE REGION SATURDAY NIGHT. WE WILL ONCE AGAIN BE IN
THE VICINITY OF THE LEFT EXIT REGION OF A JET...THIS TIME AROUND NEAR
150KTS. CYCLOGENESIS WILL BE POSSIBLE OFF OUR WATERS AND THIS IS
WHERE THE MODELS DIVERGE IN THEIR SOLUTIONS. THE EC HINTS AT A WAVE
DEVELOPING...BUT DOES NOT DEVELOP A CLOSED LOW. THE LATEST GFS AND
GEM ARE OPEN WAVE-LIKE...BUT DO DEVELOP A CLOSED 993MB AND 987 MB
LOW...RESPECTIVELY. BOTH MODELS MOVE THEIR RESPECTIVE LOW PRESSURES
INTO THE SOUTH CENTRAL OREGON COAST. MEANWHILE...THE NAM DEVELOPS A
CLOSED LOW EARLY ON...AND BRINGS A 985MB LOW INTO THE NORTH CENTRAL
OREGON COAST. THIS WOULD ALMOST CERTAINLY RESULT IN A SIGNIFICANT WIND
EVENT FOR AT LEAST PORTIONS OF THE OREGON COAST. GIVEN THIS IS A
COUPLE DAYS AWAY AND SUBTLE DIFFERENCES IN THE SYNOPTIC PATTERN CAN
DRASTICALLY CHANGE CYCLOGENESIS...A HYBRID OF THE GLOBAL MODELS IS
FAVORED...BUT THIS WILL NONETHELESS BEAR WATCHING.
IT SHOULD ALSO BE NOTED THAT A MORE OPEN WAVE LIKE PATTERN AS
DEPICTED BY THE EC WOULD LIKELY RESULT IN LOWER SNOW LEVELS AND
HIGHLIGHT WORTHY SNOWS FOR THE CASCADE PASSES. IN CONTRAST...WARM
AIR WOULD LIKELY SURGE NORTHWARD AHEAD OF THE DEVELOPING LOW
PRESSURE...PARTICULARLY IN THE NAM SCENARIO...RESULTING IN SNOW
LEVELS AT LEAST 1.5-3KFT HIGHER.
MAIN EDITS THIS EVENING WERE TO ADJUST SNOW LEVELS DOWN A BIT GIVEN
SNOW ACCUMULATIONS ALONG THE CASCADE CREST PER WEB CAMS...AND TO
INCREASE POPS A BIT OVER THE NEXT COUPLE OF DAYS GIVEN GENERAL MODEL
CONSENSUS. /NEUMAN
.LONG TERM...A SHORTWAVE UPPER RIDGE WILL MOVE OVER THE REGION MONDAY
AND PROVIDE A BRIEF BREAK IN THE MOIST WEATHER...ALTHOUGH MOIST
ONSHORE FLOW WILL LIKELY CONTINUE SHOWERS. ANOTHER UPPER LOW WILL
DROP INTO THE NE PACIFIC MONDAY AND BRING A WET FRONT THROUGH THE
REGION TUESDAY AND WEDNESDAY. MODELS HAVE STILL SHOW THE POTENTIAL
FOR AN ATMOSPHERIC RIVER EVENT WITH THIS SYSTEM...WHICH WILL BRING
THE POSSIBILITY OF HEAVY RAINFALL AND POTENTIAL FOR ANOTHER ROUND OF
HIGH RIVER LEVELS. THE MODELS HINT OF SOME SORT OF RIDGING AND
POSSIBLY DRY WEATHER LATE NEXT WEEK.
&&
.AVIATION...MOSTLY VFR CONDITIONS THIS EVENING. LOOK FOR AREAS OF
MVFR STRATUS TO DEVELOP LATE TONIGHT BOTH ALONG THE COAST AND
INLAND. VFR CONDITIONS WILL RETURN OVER INLAND LATE FRI MORNING
AND CONTINUE DURING THE AFTERNOON. EXPECT A MIX OF MVFR ALONG THE
COAST ON FRIDAY.
KPDX AND APPROACHES...VFR CIGS AND VSBY THROUGH THIS EVENING. EXPECT
MVFR STRATUS DESK BETWEEN 020 AND 030 TO DEVELOP LATE TONIGHT AND
LIFT BACK TO VFR SHORTLY BEFORE NOON ON FRIDAY. E TO SE WINDS WILL
CONTINUE THROUGH FRIDAY. TODD/BROWN
&&
.MARINE...STRONG SMALL CRAFT ADVISORY WINDS OVER THE MARINE
WATERS THIS EVENING SHOULD CONTINUE OVERNIGHT AND INTO FRIDAY.
MODELS CONTINUE TO ADVERTISE THE POSSIBILITY OF MARGINAL GALES
ACROSS MAINLY THE SOUTHERN WATERS BEGINNING FRIDAY AFTERNOON AHEAD
OF THE NEXT SYSTEM. AS A RESULT...A GALE WATCH HAS BEEN ISSUED FOR
FRIDAY AFTERNOON THROUGH FRIDAY NIGHT. FULLY EXPECT SMALL CRAFT WINDS
AT THE LEAST TO CONTINUE ACROSS ALL WATERS THROUGH SATURDAY.
SEAS WILL REMAIN IN THE MID TEENS THROUGH SATURDAY. SEAS MAY PICK
UP TO THE UPPER TEENS FRIDAY NIGHT INTO SATURDAY WITH THE
SYSTEM...ESPECIALLY ACROSS THE SOUTHERN WATERS. SEAS ARE THEN
EXPECTED TO GRADUALLY DROP TO NEAR 10 FT BY LATE SUNDAY. BROWN
&&
.PQR WATCHES/WARNINGS/ADVISORIES...
OR...NONE.
WA...NONE.
PZ...SMALL CRAFT ADVISORY FOR WINDS UNTIL 10 PM PST SATURDAY FOR
COASTAL WATERS FROM CAPE SHOALWATER WA TO CASCADE HEAD OR OUT 60
NM.
SMALL CRAFT ADVISORY FOR HAZARDOUS SEAS UNTIL 4 PM PST SUNDAY
FOR COASTAL WATERS FROM CAPE SHOALWATER WA TO CASCADE HEAD OR
OUT 60 NM.
GALE WATCH FROM FRIDAY MORNING THROUGH LATE FRIDAY NIGHT FOR
COASTAL WATERS FROM CASCADE HEAD OR TO FLORENCE OR OUT 60 NM.
SMALL CRAFT ADVISORY FOR WINDS UNTIL 10 AM PST FRIDAY FOR
COASTAL WATERS FROM CASCADE HEAD OR TO FLORENCE OR OUT 60 NM.
SMALL CRAFT ADVISORY FOR HAZARDOUS SEAS UNTIL 10 AM PST FRIDAY
FOR COASTAL WATERS FROM CASCADE HEAD OR TO FLORENCE OR OUT 60
NM.
SMALL CRAFT ADVISORY FOR ROUGH COLUMBIA RIVER BAR UNTIL 10 PM
PST FRIDAY.
&&
$$
MORE WEATHER INFORMATION ONLINE AT...HTTP://WEATHER.GOV/PORTLAND
THIS DISCUSSION IS FOR NORTHWEST OREGON AND SOUTHWEST WASHINGTON FROM
THE CASCADE CREST TO 60 NAUTICAL MILES OFFSHORE. THE AREA IS COMMONLY
REFERRED TO AS THE FORECAST AREA.
AREA FORECAST DISCUSSION
NWS PORTLAND OR
850 PM PST THU NOV 29 2012
.SYNOPSIS...A BROAD UPPER LOW OVER THE NE PACIFIC WILL SEND A SERIES
OF FRONTS ACROSS THE PACIFIC NW THROUGH THE WEEKEND. SHOWERS WILL
PERSIST TONIGHT IN THE WAKE OF A COLD FRONT..AND INCREASE FRIDAY
MORNING AS THE NEXT SYSTEM APPROACHES. THE NEXT FRONT WILL MOVE
THROUGH FRIDAY NIGHT AND SATURDAY MORNING. SNOW LEVELS WILL LOWER TO
PASS LEVEL WITH THIS SYSTEM. ANOTHER FRONT IS EXPECTED SATURDAY NIGHT
AND SUNDAY MORNING.
&&
.SHORT TERM...A MASSIVE TROUGH OVER THE EASTERN PACIFIC WILL CONTINUE
TO SPIN EMBEDDED SHORTWAVE TROUGHS ACROSS THE REGION THROUGH THE
WEEKEND. WE ARE CURRENTLY NEAR THE LEFT EXIT REGION OF AN UPPER LEVEL
JET...WHICH HAS LIKELY AIDED IN THE DEVELOPMENT OF A QUASI BAROCLINIC
LEAF OVER WEST CENTRAL OREGON. PER RADAR IMAGERY...WIDESPREAD RAIN
SHOWERS ARE SPREADING NORTHEASTWARD ACROSS THE AREA THIS EVENING.
ONCE THIS WAVE PASSES...EXPECT AT LEAST A TEMPORARY LULL IN PRECIP
ACROSS THE VALLEY DURING THE EARLY MORNING HOURS. SATELLITE
EXTRAPOLATION AND THE HRRR SUPPORT THIS GENERAL IDEA.
ANOTHER EMBEDDED VORT MAX CURRENTLY APPROACHING 130W WILL BE LAPPING
ON OUR DOORSTEP EARLY FRIDAY MORNING...WHICH SHOULD RESULT IN ANOTHER
UPTICK IN SHOWER ACTIVITY...PARTICULARLY ALONG THE COAST.
A THIRD VORT MAX CURRENTLY NEAR 50N AND 150W WILL PUSH ASHORE FRIDAY
EVENING RESULTING IN A BAND OF HEAVIER RAIN THAT WILL DROP
SOUTHEASTWARD ACROSS THE CWA FRIDAY EVENING INTO FRIDAY NIGHT. THE
COAST RANGE WILL LIKELY RECEIVE A COUPLE INCHES OF RAIN FROM THIS
EVENT...BUT AT THIS TIME...MAIN STEM RIVER FLOODING IS NOT
ANTICIPATED.
FINALLY...THE MODELS ARE IN RELATIVELY GOOD AGREEMENT THAT ANOTHER
VORT MAX AND SHORTWAVE TROUGH CURRENTLY NEAR THE ALEUTIAN ISLANDS
WILL SWING INTO THE REGION SATURDAY NIGHT. WE WILL ONCE AGAIN BE IN
THE VICINITY OF THE LEFT EXIT REGION OF A JET...THIS TIME AROUND NEAR
150KTS. CYCLOGENESIS WILL BE POSSIBLE OFF OUR WATERS AND THIS IS
WHERE THE MODELS DIVERGE IN THEIR SOLUTIONS. THE EC HINTS AT A WAVE
DEVELOPING...BUT DOES NOT DEVELOP A CLOSED LOW. THE LATEST GFS AND
GEM ARE OPEN WAVE-LIKE...BUT DO DEVELOP A CLOSED 993MB AND 987 MB
LOW...RESPECTIVELY. BOTH MODELS MOVE THEIR RESPECTIVE LOW PRESSURES
INTO THE SOUTH CENTRAL OREGON COAST. MEANWHILE...THE NAM DEVELOPS A
CLOSED LOW EARLY ON...AND BRINGS A 985MB LOW INTO THE NORTH CENTRAL
OREGON COAST. THIS WOULD ALMOST CERTAINLY RESULT IN A SIGNIFICANT WIND
EVENT FOR AT LEAST PORTIONS OF THE OREGON COAST. GIVEN THIS IS A
COUPLE DAYS AWAY AND SUBTLE DIFFERENCES IN THE SYNOPTIC PATTERN CAN
DRASTICALLY CHANGE CYCLOGENESIS...THE GLOBAL MODELS ARE FAVORED...BUT
THIS WILL NONETHELESS BEAR WATCHING.
IT SHOULD ALSO BE NOTED THAT A MORE OPEN WAVE LIKE THAT DEPICTED BY
THE EC WOULD LIKELY RESULT IN LOWER SNOW LEVELS AND HIGHLIGHT WORTHY
SNOWS FOR THE CASCADE PASSES. IN CONTRAST...WARM AIR WOULD LIKELY
SURGE NORTHWARD AHEAD OF THE DEVELOPING LOW PRESSURE...PARTICULARLY
IN THE NAM SCENARIO...RESULTING IN SNOW LEVELS AT LEAST 1.5-3KFT
HIGHER.
MAIN EDITS THIS EVENING WERE TO ADJUST SNOW LEVELS DOWN A BIT GIVEN
SNOW ACCUMULATIONS ALONG THE CASCADE CREST PER WEB CAMS...AND TO
INCREASE POPS A BIT OVER THE NEXT COUPLE OF DAYS GIVEN GENERAL MODEL
CONSENSUS. /NEUMAN
.LONG TERM...A SHORTWAVE UPPER RIDGE WILL MOVE OVER THE REGION MONDAY
AND PROVIDE A BRIEF BREAK IN THE MOIST WEATHER...ALTHOUGH MOIST
ONSHORE FLOW WILL LIKELY CONTINUE SHOWERS. ANOTHER UPPER LOW WILL
DROP INTO THE NE PACIFIC MONDAY AND BRING A WET FRONT THROUGH THE
REGION TUESDAY AND WEDNESDAY. MODELS HAVE STILL SHOW THE POTENTIAL
FOR AN ATMOSPHERIC RIVER EVENT WITH THIS SYSTEM...WHICH WILL BRING
THE POSSIBILITY OF HEAVY RAINFALL AND POTENTIAL FOR ANOTHER ROUND OF
HIGH RIVER LEVELS. THE MODELS HINT OF SOME SORT OF RIDGING AND
POSSIBLY DRY WEATHER LATE NEXT WEEK.
&&
.AVIATION...MOSTLY VFR CONDITIONS THIS EVENING. LOOK FOR AREAS OF
MVFR STRATUS TO DEVELOP LATE TONIGHT BOTH ALONG THE COAST AND
INLAND. VFR CONDITIONS WILL RETURN OVER INLAND LATE FRI MORNING
AND CONTINUE DURING THE AFTERNOON. EXPECT A MIX OF MVFR ALONG THE
COAST ON FRIDAY.
KPDX AND APPROACHES...VFR CIGS AND VSBY THROUGH THIS EVENING. EXPECT
MVFR STRATUS DESK BETWEEN 020 AND 030 TO DEVELOP LATE TONIGHT AND
LIFT BACK TO VFR SHORTLY BEFORE NOON ON FRIDAY. E TO SE WINDS WILL
CONTINUE THROUGH FRIDAY. TODD/BROWN
&&
.MARINE...STRONG SMALL CRAFT ADVISORY WINDS OVER THE MARINE
WATERS THIS EVENING SHOULD CONTINUE OVERNIGHT AND INTO FRIDAY.
MODELS CONTINUE TO ADVERTISE THE POSSIBILITY OF MARGINAL GALES
ACROSS MAINLY THE SOUTHERN WATERS BEGINNING FRIDAY AFTERNOON AHEAD
OF THE NEXT SYSTEM. AS A RESULT...A GALE WATCH HAS BEEN ISSUED FOR
FRIDAY AFTERNOON THROUGH FRIDAY NIGHT. FULLY EXPECT SMALL CRAFT WINDS
AT THE LEAST TO CONTINUE ACROSS ALL WATERS THROUGH SATURDAY.
SEAS WILL REMAIN IN THE MID TEENS THROUGH SATURDAY. SEAS MAY PICK
UP TO THE UPPER TEENS FRIDAY NIGHT INTO SATURDAY WITH THE
SYSTEM...ESPECIALLY ACROSS THE SOUTHERN WATERS. SEAS ARE THEN
EXPECTED TO GRADUALLY DROP TO NEAR 10 FT BY LATE SUNDAY. BROWN
&&
.PQR WATCHES/WARNINGS/ADVISORIES...
OR...NONE.
WA...NONE.
PZ...SMALL CRAFT ADVISORY FOR WINDS UNTIL 10 PM PST SATURDAY FOR
COASTAL WATERS FROM CAPE SHOALWATER WA TO CASCADE HEAD OR OUT 60
NM.
SMALL CRAFT ADVISORY FOR HAZARDOUS SEAS UNTIL 4 PM PST SUNDAY
FOR COASTAL WATERS FROM CAPE SHOALWATER WA TO CASCADE HEAD OR
OUT 60 NM.
GALE WATCH FROM FRIDAY MORNING THROUGH LATE FRIDAY NIGHT FOR
COASTAL WATERS FROM CASCADE HEAD OR TO FLORENCE OR OUT 60 NM.
SMALL CRAFT ADVISORY FOR WINDS UNTIL 10 AM PST FRIDAY FOR
COASTAL WATERS FROM CASCADE HEAD OR TO FLORENCE OR OUT 60 NM.
SMALL CRAFT ADVISORY FOR HAZARDOUS SEAS UNTIL 10 AM PST FRIDAY
FOR COASTAL WATERS FROM CASCADE HEAD OR TO FLORENCE OR OUT 60
NM.
SMALL CRAFT ADVISORY FOR ROUGH COLUMBIA RIVER BAR UNTIL 10 PM
PST FRIDAY.
&&
$$
MORE WEATHER INFORMATION ONLINE AT...HTTP://WEATHER.GOV/PORTLAND
THIS DISCUSSION IS FOR NORTHWEST OREGON AND SOUTHWEST WASHINGTON FROM
THE CASCADE CREST TO 60 NAUTICAL MILES OFFSHORE. THE AREA IS COMMONLY
REFERRED TO AS THE FORECAST AREA.
AREA FORECAST DISCUSSION
NWS NASHVILLE TN
350 AM CST FRI NOV 30 2012
.DISCUSSION...
IN THE SHORT TERM...NOT MUCH TO SPEAK OF OTHER THAN SEEING IF
IMPROVEMENTS COULD BE MADE ON THE GFS TEMP INITIALIZATION. TRENDED A
BIT ABOVE THE GUIDANCE AS IT HAS BEEN TRENDING TOWARDS BEING TOO COOL
AS OF LATE. ALSO TWEAKED THE FIRST PERIOD SKY GRIDS TO INCLUDE THE
CIRRUS SEEN ON IR SATELLITE. NAM AND RUC LAYER RH SHOWS SOME
INCREASE IN LOW LEVEL RH THIS AFTERNOON WHICH SHOULD BRING A BIT OF
CLOUD COVER ON THE CUMBERLAND SO INCLUDED THIS INTO THE SKY GRIDS.
IN THE LONG TERM...THE FOCUS RESIDES ON THE UPCOMING FRONTAL PASSAGE
THAT IS PROGGED TO REACH MIDDLE TN BY TUESDAY AFTERNOON AS INDICATED
BY THE GFS OR EVENING PER THE ECMWF. LATEST MODEL RUNS ARE REALLY
LACKING APPRECIABLE INSTABILITY AND SHEAR. WHILE DYNAMICAL FORCING
WILL BE SUFFICIENT FOR RAIN WITH A LIGHTNING STRIKE OR TWO...THE
CONFIDENCE IN WIDESPREAD TSRA IS LOW. FORECAST SOUNDINGS...WHILE
VERY MOIST...SHOW NEARLY ZERO CAPE AND EVEN SOME CIN IN PLACE DURING
PEAK HEATING TUESDAY. LOOKS LIKE LIFT WILL BE MOSTLY DYNAMICAL AND
EVEN THAT COULD BE BETTER AS 500 MB WINDS ARE ONLY IN THE 35-40 KT
RANGE. FEEL PREVIOUS FORECAST WAS PRETTY GOOD FOR POP CHANCES AND
OTHER THAN FINE TUNING SOME TIMING AND WX WORDING...NOT MUCH WAS
CHANGED. FEEL LIKE THIS WILL BE A MODERATE TO HEAVY RAINER AND NOT
MUCH ELSE.
BEYOND THIS FRONTAL SYSTEM...A TRANSITION PERIOD OF WEAK RIDGING
PRIOR TO THE NEXT SIGNIFICANT FRONTAL PASSAGE. AS FAR AS THE MODEL
COMPARISON GOES...THE DEPICTION OF THE 500 MB LOW IS QUITE DIFFERENT
IN BOTH TIMING AND CHARACTER. GFS DEPICTION ISNT QUITE AS DEEP WITH
THE HEIGHT FALLS...HOW FAR SOUTH THE LOW DIPS...OR AS SIGNIFICANT IN
THE POSITIVE TILT. THE ECMWF SOLUTION WOULD BE AN EYE OPENER FOR
STORM POSSIBILITIES AS IT GENERATES A HEALTHY PRE FRONTAL
TROUGH...NEAR 60 SFC DEWPOINTS AND A PROGGED 55 KT 850 MB JET. THE
ONLY REAL AGREEMENT IS THAT THE FRONT WILL EVENTUALLY PASS THROUGH
SOMETIME AROUND 12Z SATURDAY...GIVE OR TAKE 6 HOURS...AND IT WILL
PRODUCE RAIN. BECAUSE OF THIS...THATS WHAT WAS INCLUDED IN THE
GRIDS.
&&
.PRELIMINARY POINT TEMPS/POPS...
NASHVILLE 63 44 65 49 / 0 0 05 10
CLARKSVILLE 61 43 65 51 / 0 05 05 20
CROSSVILLE 56 43 60 45 / 0 0 05 10
COLUMBIA 63 44 66 49 / 0 0 05 10
LAWRENCEBURG 62 44 67 48 / 0 0 05 10
WAVERLY 62 43 66 51 / 0 05 05 10
&&
.OHX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
TB12
AREA FORECAST DISCUSSION
NWS CHARLESTON SC
946 AM EST FRI NOV 30 2012
.SYNOPSIS...
HIGH PRESSURE WILL PREVAIL THROUGH EARLY NEXT WEEK...WHILE A WEAK
COASTAL TROUGH PERSISTS ALONG THE SOUTHEAST COAST. A COLD FRONT
THEN EXPECTED TO CROSS THE REGION DURING THE MIDDLE OF NEXT WEEK.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
HIGH PRESSURE EXTENDS ACROSS THE REGION WITH A SUBTLE COASTAL
TROUGH NOTED JUST OFFSHORE. THE RISK FOR ISOLATED SHOWERS APPEARS
TO BE DIMINISHING SOUTH OF I-16...SO MENTIONABLE POPS HAVE BEEN
REMOVED FROM THIS AREA WITH SUPPORT FROM BOTH THE RAP AND H3R.
THE BIGGEST FORECAST CHALLENGE FOR THIS AFTERNOON IS SKY COVER.
EARLIER STRATOCUMULUS AFFECTING INLAND AREAS APPEARS TO BE
DIMINISHING SLIGHTLY PER VISIBLE SATELLITE TRENDS AS DIURNAL
MIXING DEEPENS. LATEST SHORT TERM GUIDANCE IS TRENDING WITH LESS
CLOUD COVER TODAY...BUT STILL EXPECT A HEALTHY BLEND OF
PARTLY/MOSTLY CLOUDY SKIES THROUGH LATE AFTERNOON AS A MIXTURE
OF STRATOCUMULUS AND CIRRUS TRAVERSES THE AREA. HIGHS IN THE UPPER
60S LOOK ON TRACK AWAY FROM THE BEACHES.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH MONDAY/...
TONIGHT...SURFACE HIGH PRESSURE OVER THE WESTERN ATLANTIC WILL BECOME
ABSORBED BY A STRONGER HIGH PRESSURE SYSTEM MOVING INTO NORTHERN
NEW ENGLAND. IT APPEARS THAT THE WEAK COASTAL TROUGH JUST OFFSHORE
COULD AT LEAST BRIEFLY DAMPEN OUT...BEFORE REDEVELOPING LATE
TONIGHT. WHILE STRATOCUMULUS WILL PERSIST...THE COVERAGE MAY
DIMINISH SOME WITH GENERALLY PARTLY CLOUDY SKIES EXPECTED ACROSS
THE AREA. ANY ISOLATED SHOWERS THAT FORM IN THE LATE EVENING AND
OVERNIGHT HOURS SHOULD REMAIN OFFSHORE...BUT COULD NOT RULE OUT A
FEW SKIRTING THE SOUTHEAST GEORGIA COAST. RADIATIONAL COOLING
SHOULD BE BEST IN PARTS OF THE CHARLESTON TRI-COUNTY AREA WHERE
LOWS IN THE LOWER TO MID 40S ARE EXPECTED. ELSEWHERE...SLIGHTLY
BETTER COVERAGE OF CLOUD COVER SHOULD RESULT IN LOWS IN THE MID TO
UPPER 40S AWAY FROM THE WARMER BEACHES.
SATURDAY THROUGH MONDAY...DEEP HIGH PRESSURE WILL BUILD ACROSS
THE REGION THIS PERIOD BUT THERE WILL BE A TROUGH OF LOW PRESSURE
JUST OFFSHORE MOST OF THE TIME WHICH WILL LEAD TO PERIODS OF
MAINLY LIGHT SHOWERS...ESPECIALLY NEAR THE COAST.
OTHERWISE...TEMPERATURES WILL BE ABOVE NORMAL...ESPECIALLY BY
MONDAY WHEN HIGHS WILL PUSH INTO THE MID 70S AWAY FROM THE
IMMEDIATE COAST.
&&
.LONG TERM /MONDAY NIGHT THROUGH THURSDAY/...
AN UPPER TROUGH OF LOW PRESSURE ALONG WITH A SURFACE COLD FRONT LOOK
TO AFFECT THE AREA BY THE MIDDLE OF THE WEEK BUT DEEP MOISTURE AND
STRONG FORCING IS GOING TO BE LACKING AND THUS THE PROSPECTS FOR
MUCH RAINFALL APPEAR SMALL. TEMPERATURES WILL BE ABOVE NORMAL UNTIL
THURSDAY WHEN COOLER HIGH PRESSURE SETS UP TO THE NORTH. BY FRIDAY
THE HIGH BEGINS TO RETREAT INTO THE ATLANTIC WITH A POSSIBLE TROUGH
OF LOW PRESSURE ACROSS THE NEARBY COASTAL WATERS.
&&
.AVIATION /15Z FRIDAY THROUGH TUESDAY/...
VFR CONDITIONS ARE EXPECTED TO PREVAIL AT KCHS AND KSAV THROUGH
12Z SATURDAY. A WEAK COASTAL TROUGH OFF THE GEORGIA COAST WILL
MAINTAIN A MOIST LOW-LEVEL ONSHORE FLOW ACROSS SOUTHEAST GEORGIA
THROUGH MUCH OF THE FORECAST PERIOD. THIS SHOULD RESULT IN A BROKEN
DECK OF STRATOCUMULUS AT KSAV WITH MAINLY VFR CEILINGS THROUGH
THIS AFTERNOON. AT KCHS...THE STRATOCUMULUS SHOULD BECOME
SCATTERED IN COVERAGE DURING THE DAY...BUT NO CEILINGS ARE
ANTICIPATED.
EXTENDED OUTLOOK...PERIODS OF REDUCED CEILINGS AND/OR VISIBILITIES
ARE POSSIBLE DURING THE LATE NIGHT/EARLY MORNING HOURS INTO EARLY
NEXT WEEK.
&&
.MARINE...
TODAY AND TONIGHT...HIGH PRESSURE WILL SHIFT OFF THE NORTH
CAROLINA COAST THEN BECOME ABSORBED BY A STRONGER AREA OF HIGH
PRESSURE MOVING INTO NORTHERN NEW ENGLAND LATER TONIGHT.
MEANWHILE...A WEAK COASTAL TROUGH WILL PERSIST THROUGH THIS
AFTERNOON...WEAKEN/DISSIPATE THIS EVENING THEN REDEVELOP LATER
TONIGHT. A NORTHEAST FLOW WILL PREVAIL OVER THE COASTAL
WATERS...BUT WHEN THE COASTAL TROUGH IS PRESENT THE SURFACE
PRESSURE GRADIENT WILL PINCH AND CAUSE WINDS TO SURGE UPWARDS OF
15 KT AT TIMES WEST OF THE TROUGH AXIS...OR MAINLY ACROSS PARTS OF
THE NEAR SHORE WATERS. SEAS WILL GENERALLY BE IN THE 2-3 FT
RANGE...BUT A FEW 4 FT SEAS ARE POSSIBLE AT TIMES IN THE OUTER
GEORGIA WATERS.
SATURDAY THROUGH WEDNESDAY...HIGH PRESSURE WILL CONTINUE TO BE THE
DOMINANT WEATHER FEATURE ACROSS THE AREA THROUGH EARLY NEXT WEEK
WITH A TROUGH OF LOW PRESSURE LINGERING NEARBY. A COLD FRONT WILL
THEN PUSH THROUGH WEDNESDAY. SEAS COULD BUILD UP TO 5 FT BEYOND 20
NM INTO SUNDAY GIVEN THE PERSISTENT NORTHEAST FETCH BUT NO HEADLINES
ARE EXPECTED FOR WINDS AND/OR SEAS.
&&
.CHS WATCHES/WARNINGS/ADVISORIES...
GA...NONE.
SC...NONE.
MARINE...NONE.
&&
$$
ST
AREA FORECAST DISCUSSION
NWS GOODLAND KS
858 AM MST FRI NOV 30 2012
.UPDATE...
ISSUED AT 851 AM MST FRI NOV 30 2012
JUST COMPLETED AN UPDATE. MAIN CHANGE PER SATELLITE AND NEWEST
MODEL DATA WAS TO INCREASE CLOUD COVER...ESPECIALLY FOR OUR NORTHERN
LOCATIONS...FOR TODAY. THIS INCREASE IS DUE TO A LEFT FRONT QUADRANT
OF A JET MOVING THROUGH. ALSO INCREASED SKY COVER FOR LATER TONIGHT
INTO TOMORROW. BECAUSE OF THE COLD START TODAY...MORE CLOUD
COVER...WHAT LOOKS TO BE A LATER CHANGE TO SOUTHERLY WINDS...AND
NEWEST MODEL DATA WHICH IS A LITTLE COOLER...CHOSE TO COOL OFF THE
MAXES TODAY A FEW DEGREES. ADJUSTED WINDS AS WELL FOR TODAY BASED
ON LATEST RUC AND OBSERVATIONAL TRENDS.
&&
.SHORT TERM...(TODAY THROUGH SUNDAY NIGHT)
ISSUED AT 303 AM MST FRI NOV 30 2012
WARM AND DRY CONDITIONS CONTINUE.
AN UPPER LEVEL SHORT WAVE RIDGE WILL MOVE ACROSS THE REGION TODAY WITH
A WEAK SHORT WAVE TROUGH MOVING THROUGH THE UPPER FLOW ON
SATURDAY. A SURFACE TROUGH WILL MOVE ACROSS THE CENTRAL HIGH
PLAINS ON SATURDAY IN RESPONSE TO THE UPPER SHORT WAVE MOVING
ACROSS THE REGION.
ANOTHER COUPLE OF SHORT WAVE TROUGHS WILL MOVE ACROSS THE REGION BETWEEN
LATE SUNDAY AND EARLY MONDAY MORNING AHEAD OF THE NEXT LARGER
TROUGH DUE THROUGH THE AREA ON MONDAY. THE PRE-FRONTAL SURFACE
TROUGH WILL DEEPEN OVER EASTERN COLORADO ON SUNDAY AND SUNDAY
NIGHT AHEAD OF THE COLD FRONT EXPECTED ON MONDAY.
.LONG TERM...(MONDAY THROUGH THURSDAY)
ISSUED AT 303 AM MST FRI NOV 30 2012
A COLD FRONT WILL MOVE ACROSS THE AREA EARLY MONDAY FOLLOWED BY AN
UPPER LEVEL SHORT WAVE TROUGH. MODELS CONTINUE TO PUSH THE BETTER
LIFT AND MOISTURE NORTH...SO THE AREA WILL ONLY SEE A FEW CLOUDS AT
BEST. THE NEXT COLD FRONT MOVES THROUGH THURSDAY FOLLOWED BY AN
UPPER LEVEL TROUGH THURSDAY NIGHT. AS WITH THE PREVIOUS
TROUGH...THE MAJORITY OF THE LIFT AND MOISTURE WILL BE NORTH OF THE
AREA. HOWEVER THERE WILL BE SOME LIFT AND MOISTURE OVER THE AREA TO
WORK WITH AS THE UPPER LEVEL TROUGH MOVES THROUGH. CHANCES FOR
PRECIP DO NOT LOOK TOO GOOD...BUT ENOUGH TO WARRANT A MENTION OF
PRECIP. DESPITE THE PASSAGE OF THE COLD FRONTS...TEMPERATURES FOR
THE PERIOD WILL BE SIMILAR TO THE LAST FEW DAYS. MODELS CONTINUE TO
INDICATE A THREAT FOR HAZARDOUS FIRE WEATHER CONDITIONS MONDAY
AFTERNOON BEHIND THE FIRST COLD FRONT...AS RELATIVE HUMIDITIES FALL
TO LESS THAN 20 PERCENT AND WINDS GUST TO 30 MPH.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SATURDAY MORNING)
ISSUED AT 559 AM MST FRI NOV 30 2012
VFR CONDITIONS WILL CONTINUE WITH PERIODIC INCREASES AND DECREASES
IN HIGH CLOUDS OVER THE NEXT 24 HOURS. LIGHT AND VARIABLE WINDS
AFTER 12Z WILL BECOME SOUTH AND POSSIBLY GUSTY BY 18Z AND THEN
TURN TO THE SOUTHWEST AND BECOME LIGHT AGAIN AFTER 00Z.
&&
.GLD WATCHES/WARNINGS/ADVISORIES...
KS...NONE.
CO...NONE.
NE...NONE.
&&
$$
UPDATE...BULLER
SHORT TERM...LOCKHART
LONG TERM...JTL
AVIATION...LOCKHART
AREA FORECAST DISCUSSION...UPDATED AVIATION
NWS ST LOUIS MO
557 AM CST FRI NOV 30 2012
.SHORT TERM...
ISSUED AT 350 AM CST FRI NOV 30 2012
(TODAY)
UNSEASONABLY MILD LATE AUTUMN NIGHT SHOULD BE A LEAD-IN TO AN
UNSEASONABLY WARM LATE NOVEMBER DAY FOR THE CWA...AND CLOUDS WILL BE
THE DETERIMINING FACTOR ON HOW WARM WE WILL GET THIS AFTERNOON.
MODELS ARE FORECASTING THE INCREASE IN LOW LEVEL RH TO BEGIN
TODAY...AND INDEED THE LOW CLOUD SATELLITE ENHANCEMENT HAS INDICATED
SOME CLOUDS FORMING OVER E OK AND W CENTRAL/NW AR OVER THE PAST FEW
HOURS...WITH A FEW CLOUDS ALSO JUST BEGINNING TO SHOW UP SE OF A
VIH-FAM LINE. HOWEVER... BELIEVE THIS INITIAL SURGE WILL BE FAIRLY
SHALLOW AND MAY HAVE A DIFFICULT TIME MAINTAINING A PERSISTENT CLOUD
DECK. RAP DATA SUGGESTS THAT THE BEST LOW LEVEL MOISTURE RETURN
THROUGH TODAY WILL REMAIN TO OUR S...BOTTLED UP BY THE ARKANSAS
PORTION OF THE OZARK PLATEAU/BOSTON MOUNTAINS. BASED ON THE THINKING
THAT THERE SHOULD BE A FAIR AMOUNT OF SUNSHINE TODAY HAVE ONCE AGAIN
TRENDED TO THE WARMER MET NUMBERS...WITH HIGHS RANGING FROM AROUND
60 IN FAR N/E COUNTIES OF THE CWA TO THE MIDDLE 60S ALONG AND S OF
THE I-70 CORRIDOR IN MO.
TRUETT
&&
.LONG TERM...
ISSUED AT 350 AM CST FRI NOV 30 2012
(TONIGHT THROUGH SUNDAY NIGHT)
A LOT TO DEAL WITH IN THE SHORT TERM...AS FORECAST AREA TO SEE WELL
ABOVE NORMAL TEMPERATURES THROUGH THE PERIOD...DESPITE A BIT MORE
CLOUDS OVER THE REGION THROUGH THE WEEKEND.
FOR TONIGHT...WEAK WARM FRONT TO LIFT NORTH OF FORECAST AREA...SO
ANY PATCHY FOG THAT MAY FORM OVER NORTHERN PORTIONS OF FORECAST
EARLY ON...WILL IMPROVE AS WINDS PICKUP FROM THE SOUTH.
OTHERWISE...LOWS WILL ONLY BE IN THE 40S.
THEN ON SATURDAY LOW LEVEL MOISTURE WILL CONTINUE TO BE ON THE
INCREASE AHEAD OF COLD FRONT THAT WILL SLIDE THROUGH AREA SATURDAY
NIGHT...BEFORE WEAKENING/WASHING OUT ON SUNDAY. SOME CONCERN ABOUT
STRATUS ADVECTING NORTH INTO SOUTHERN PORTIONS OF FORECAST AREA
SATURDAY MORNING AHEAD OF SYSTEM...BUT BUFKIT SOUNDINGS HAVE BRIEF
LOW CIGS WITH STRATUS THEN LIFT BY MID MORNING. SO FOR NOW HAVE NOT
ADDED MENTION OF DRIZZLE IN THIS AREA. OTHERWISE...WILL SEE SOME
LIGHT RAIN DEVELOP OVER NORTHERN PORTIONS OF FORECAST AREA AHEAD OF
COLD FRONT SATURDAY AFTERNOON. AMOUNTS WITH THIS SYSTEM WILL BE
RATHER LIGHT...SO JUST WENT WITH LOW CHANCE POPS AND LIGHT RAIN. AS
FOR TEMPS...WITH MORE CLOUDS FORECAST OVER THE REGION...LOWERED HIGH
TEMPS A FEW DEGREES...INTO THE LOW TO MID 60S.
BETTER CHANCES OF LIGHT RAIN SATURDAY NIGHT...BUT STILL NOT A LOT OF
QPF WITH FRONTAL BOUNDARY...SO KEPT LOW CHANCE POPS FOR AREAS ALONG
AND NORTH OF A STEELVILLE MO TO SPARTA IL LINE. ANOTHER MILD NIGHT
IN STORE WITH LOWS ONLY IN THE LOW TO MID 50S.
ON SUNDAY THE FRONTAL BOUNDARY WILL WASHOUT ALONG I-44 CORRIDOR...SO
SOME LINGERING LIGHT RAIN POSSIBLE ALONG AND SOUTH OF THIS AREA
DURING THE DAY...WHICH COULD LINGER INTO SUNDAY NIGHT...BUT
CONFIDENCE IS LOW...SO KEPT MENTION OUT FOR NOW. AS FOR
TEMPS...CLOUDS TO THIN OUT FOR NORTHERN PORTIONS OF FORECAST AREA
AND WINDS TO PICKUP FROM THE SOUTHWEST. SO WILL SEE NEAR RECORD
HIGHS WITH TEMPS IN THE 65 TO 70 DEGREE RANGE. MILD TEMPS TO PERSIST
SUNDAY NIGHT...WILL LOWS IN THE MID TO UPPER 50S.
(MONDAY THROUGH THURSDAY)
BY MONDAY...A MORE VIGOROUS SYSTEM TO APPROACH THE REGION WITH A
COLD FRONT SLIDING THROUGH DURING THE AFTERNOON AND EVENING HOURS.
SOME DECENT INSTABILITY...LIFT AND LOW LEVEL MOISTURE...SO SHOULD
SEE SHOWERS AND SOME THUNDERSTORMS. HIGHS ON MONDAY WILL REMAIN WELL
ABOVE NORMAL IN THE UPPER 60S TO LOW 70S...NEAR RECORD HIGHS FOR A
NUMBER OF LOCATIONS. LOWS MONDAY NIGHT WILL BE IN THE LOW 40S FAR
NORTH TO THE LOW 50S FAR SOUTHEAST.
BY TUESDAY...SHOWERS TO TAPER OFF AND COLDER AIR TO FILTER IN.
HOWEVER...NOT A LOT OF CAA WITH SYSTEM...SO TEMPS WILL STILL BE A
BIT ABOVE NORMAL...IN THE LOW 50S NORTH TO THE UPPER 50S SOUTH.
BEYOND THAT...SURFACE RIDGE TO BUILD IN WITH NEAR NORMAL TEMPS FOR
THE REST OF THE FORECAST PERIOD.
BYRD
&&
.AVIATION...
ISSUED AT 538 AM CST FRI NOV 30 2012
LOW LEVEL JET APPEARS TO BE IN THE PROCESS OF BACKING OFF A BIT
ACCORDING TO THE LATEST REGIONAL VWPS AND RAP DATA...HOWEVER
SPEEDS ARE STILL CLOSE ENOUGH THAT WE WILL CARRY WIND SHEAR
THROUGH 14Z.
OTHERWISE...VFR CONDITIONS WILL CONTINUE ACROSS THE AREA
TODAY...BUT WITH TIME PERSISTENT S LOW LEVEL FLOW WILL BE
MOISTENING THE LOWER LEVELS OF THE AMS CAUSING A DETERIORATION OF
AVIATION WEATHER CONDITIONS. LOW CLOUD SATELLITE LOOP ALREADY
INDICATES LOTS OF STRATUS FORMING AND ADVECTING NE FROM W AR TO E
TX...BUT IT SURE LOOKS LIKE THE NWD PUSH HAS BEEN BLOCKED BY THE
OZARKS PLATEAU...AND IF 00/06Z MODELS ARE TO BE BELIEVED LOWER
LEVEL MOISTURE SHOULD NOT ARRIVE IN OUR AREA UNTIL LATER
TONIGHT...AFTER 06Z. UNFORTUNATELY...SHORT RANGE MODELS VARY
CONSIDERABLY ON WHEN AND HOW THIS LOW LEVEL MOISTURE WILL COME
INTO THE AREA...AS FOG AND/OR STRATUS. FOR NOW HAVE ATTEMPTED TO
INDICATE THESE DETERIORATING CONDITIONS WITH VSBYS/CIGS DROPPING
IN MVFR CAT IN THE 09-12Z TIME FRAME. THIS DOVETAILS WITH THE SREF
CIG/VSBYS PROBABILITY PROGS WHICH SUGGEST LOWERING CONDITIONS
TOWARDS THE END OF THIS TAF FORECAST PERIOD.
SPECIFICS FOR KSTL...LOW LEVEL WIND SHEAR THREAT WILL CONTINUE FOR
SEVERAL MORE HOURS...BUT ALL MODELS AGREE 1KFT WINDS SHOULD BE
DROPPING INTO THE 25-30KT RANGE BY 14Z.
MODEL CONSENSUS SUGGESTS VFR CONDITIONS WILL CONTINUE OVER THE
AREA TODAY AND INTO THIS EVENING...WITH ONLY A FEW HIGH LEVEL
CLOUDS TODAY AND SW SURFACE WINDS AOB 10 KTS. AFOREMENTIONED
LOWERING OF CIGS/VSBYS SHOULD TAKE PLACE AFTER 06Z TONIGHT.
TRUETT
&&
.CLIMATE...
ISSUED AT 504 PM CST WED NOV 28 2012
ABOVE NORMAL TEMPERATURES ARE FORECAST THIS WEEKEND. HERE ARE THE
RECORD HIGH AND HIGH MINIMUM TEMPERATURES FOR THE FIRST THREE DAYS
OF DECEMBER FOR THE CITIES OF ST. LOUIS...COLUMBIA...AND QUINCY.
RECORD HIGH TEMPERATURES...
ST. LOUIS COLUMBIA QUINCY
SATURDAY 12/1 73F (1970) 68F (1982) 67F (1913)
SUNDAY 12/2 74F (1982) 72F (1917) 67F (1982)
MONDAY 12/3 76F (1970) 72F (1998) 71F (1970)
RECORD HIGH MINIMUM TEMPERATURES...
ST. LOUIS COLUMBIA QUINCY
SATURDAY 12/1 53F (1980) 53F (1921) 52 (1913)
SUNDAY 12/2 63F (1982) 59F (1982) 59 (1982)
MONDAY 12/3 62F (1998) 58F (1998) 59 (1998)
&&
.LSX WATCHES/WARNINGS/ADVISORIES...
MO...NONE.
IL...NONE.
&&
$$
WFO LSX
AREA FORECAST DISCUSSION
NWS NASHVILLE TN
842 AM CST FRI NOV 30 2012
.UPDATE...UPDATED ZONE PACKAGE TO ACCOUNT FOR CURRENT CLOUD CONDITIONS
AND TRENDS.
&&
.PREV DISCUSSION... /ISSUED 626 AM CST FRI NOV 30 2012/
UPDATE...FOR 12Z AVIATION FORECAST
AVIATION...
STRATOCUMULUS ARE MOVING NORTH FROM ALABAMA BASED AROUND 25 HNDRD
FEET MSL. THESE CLOUDS APPEAR TO BE RIDING ALONG THE 290 KELVIN
SURFACE ON A SOUTHWESTERLY 30 KNOT LOW LEVEL JET. EXPECT THESE
CLOUDS TO BE AROUND THROUGH 14Z-15Z TIME FRAME OR UNTIL MIXING CAN
GET UNDERWAY...THEN THEY SHOULD THIN OUT. OTHERWISE LOOK FOR VFR
CONDITIONS TO PREVAIL THROUGH THE NEXT 24 HOURS WITH WINDS BECOMING
GUSTY DURING THE DAY AS SURFACE PRESSURE GRADIENT TIGHTENS A BIT
FROM CAROLINA HIGH PRESSURE CENTER TO OUR EAST AND CENTRAL PLAINS
LOW. EXPECT WIND GUSTS TO 18 KNOTS DURING THE DAY WITH WINDS
SUBSIDING BY EARLY EVENING.
BOYD
PREV DISCUSSION... /ISSUED 350 AM CST FRI NOV 30 2012/
DISCUSSION...
IN THE SHORT TERM...NOT MUCH TO SPEAK OF OTHER THAN SEEING IF
IMPROVEMENTS COULD BE MADE ON THE GFS TEMP INITIALIZATION. TRENDED A
BIT ABOVE THE GUIDANCE AS IT HAS BEEN TRENDING TOWARDS BEING TOO COOL
AS OF LATE. ALSO TWEAKED THE FIRST PERIOD SKY GRIDS TO INCLUDE THE
CIRRUS SEEN ON IR SATELLITE. NAM AND RUC LAYER RH SHOWS SOME
INCREASE IN LOW LEVEL RH THIS AFTERNOON WHICH SHOULD BRING A BIT OF
CLOUD COVER ON THE CUMBERLAND SO INCLUDED THIS INTO THE SKY GRIDS.
IN THE LONG TERM...THE FOCUS RESIDES ON THE UPCOMING FRONTAL PASSAGE
THAT IS PROGGED TO REACH MIDDLE TN BY TUESDAY AFTERNOON AS INDICATED
BY THE GFS OR EVENING PER THE ECMWF. LATEST MODEL RUNS ARE REALLY
LACKING APPRECIABLE INSTABILITY AND SHEAR. WHILE DYNAMICAL FORCING
WILL BE SUFFICIENT FOR RAIN WITH A LIGHTNING STRIKE OR TWO...THE
CONFIDENCE IN WIDESPREAD TSRA IS LOW. FORECAST SOUNDINGS...WHILE
VERY MOIST...SHOW NEARLY ZERO CAPE AND EVEN SOME CIN IN PLACE DURING
PEAK HEATING TUESDAY. LOOKS LIKE LIFT WILL BE MOSTLY DYNAMICAL AND
EVEN THAT COULD BE BETTER AS 500 MB WINDS ARE ONLY IN THE 35-40 KT
RANGE. FEEL PREVIOUS FORECAST WAS PRETTY GOOD FOR POP CHANCES AND
OTHER THAN FINE TUNING SOME TIMING AND WX WORDING...NOT MUCH WAS
CHANGED. FEEL LIKE THIS WILL BE A MODERATE TO HEAVY RAINER AND NOT
MUCH ELSE.
BEYOND THIS FRONTAL SYSTEM...A TRANSITION PERIOD OF WEAK RIDGING
PRIOR TO THE NEXT SIGNIFICANT FRONTAL PASSAGE. AS FAR AS THE MODEL
COMPARISON GOES...THE DEPICTION OF THE 500 MB LOW IS QUITE DIFFERENT
IN BOTH TIMING AND CHARACTER. GFS DEPICTION ISNT QUITE AS DEEP WITH
THE HEIGHT FALLS...HOW FAR SOUTH THE LOW DIPS...OR AS SIGNIFICANT IN
THE POSITIVE TILT. THE ECMWF SOLUTION WOULD BE AN EYE OPENER FOR
STORM POSSIBILITIES AS IT GENERATES A HEALTHY PRE FRONTAL
TROUGH...NEAR 60 SFC DEWPOINTS AND A PROGGED 55 KT 850 MB JET. THE
ONLY REAL AGREEMENT IS THAT THE FRONT WILL EVENTUALLY PASS THROUGH
SOMETIME AROUND 12Z SATURDAY...GIVE OR TAKE 6 HOURS...AND IT WILL
PRODUCE RAIN. BECAUSE OF THIS...THATS WHAT WAS INCLUDED IN THE
GRIDS.
&&
.OHX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
18
AREA FORECAST DISCUSSION
NWS NASHVILLE TN
626 AM CST FRI NOV 30 2012
.UPDATE...FOR 12Z AVIATION FORECAST
&&
.AVIATION...
STRATOCUMULUS ARE MOVING NORTH FROM ALABAMA BASED AROUND 25 HNDRD
FEET MSL. THESE CLOUDS APPEAR TO BE RIDING ALONG THE 290 KELVIN
SURFACE ON A SOUTHWESTERLY 30 KNOT LOW LEVEL JET. EXPECT THESE
CLOUDS TO BE AROUND THROUGH 14Z-15Z TIME FRAME OR UNTIL MIXING CAN
GET UNDERWAY...THEN THEY SHOULD THIN OUT. OTHERWISE LOOK FOR VFR
CONDITIONS TO PREVAIL THROUGH THE NEXT 24 HOURS WITH WINDS BECOMING
GUSTY DURING THE DAY AS SURFACE PRESSURE GRADIENT TIGHTENS A BIT
FROM CAROLINA HIGH PRESSURE CENTER TO OUR EAST AND CENTRAL PLAINS
LOW. EXPECT WIND GUSTS TO 18 KNOTS DURING THE DAY WITH WINDS
SUBSIDING BY EARLY EVENING.
BOYD
&&
.PREV DISCUSSION... /ISSUED 350 AM CST FRI NOV 30 2012/
DISCUSSION...
IN THE SHORT TERM...NOT MUCH TO SPEAK OF OTHER THAN SEEING IF
IMPROVEMENTS COULD BE MADE ON THE GFS TEMP INITIALIZATION. TRENDED A
BIT ABOVE THE GUIDANCE AS IT HAS BEEN TRENDING TOWARDS BEING TOO COOL
AS OF LATE. ALSO TWEAKED THE FIRST PERIOD SKY GRIDS TO INCLUDE THE
CIRRUS SEEN ON IR SATELLITE. NAM AND RUC LAYER RH SHOWS SOME
INCREASE IN LOW LEVEL RH THIS AFTERNOON WHICH SHOULD BRING A BIT OF
CLOUD COVER ON THE CUMBERLAND SO INCLUDED THIS INTO THE SKY GRIDS.
IN THE LONG TERM...THE FOCUS RESIDES ON THE UPCOMING FRONTAL PASSAGE
THAT IS PROGGED TO REACH MIDDLE TN BY TUESDAY AFTERNOON AS INDICATED
BY THE GFS OR EVENING PER THE ECMWF. LATEST MODEL RUNS ARE REALLY
LACKING APPRECIABLE INSTABILITY AND SHEAR. WHILE DYNAMICAL FORCING
WILL BE SUFFICIENT FOR RAIN WITH A LIGHTNING STRIKE OR TWO...THE
CONFIDENCE IN WIDESPREAD TSRA IS LOW. FORECAST SOUNDINGS...WHILE
VERY MOIST...SHOW NEARLY ZERO CAPE AND EVEN SOME CIN IN PLACE DURING
PEAK HEATING TUESDAY. LOOKS LIKE LIFT WILL BE MOSTLY DYNAMICAL AND
EVEN THAT COULD BE BETTER AS 500 MB WINDS ARE ONLY IN THE 35-40 KT
RANGE. FEEL PREVIOUS FORECAST WAS PRETTY GOOD FOR POP CHANCES AND
OTHER THAN FINE TUNING SOME TIMING AND WX WORDING...NOT MUCH WAS
CHANGED. FEEL LIKE THIS WILL BE A MODERATE TO HEAVY RAINER AND NOT
MUCH ELSE.
BEYOND THIS FRONTAL SYSTEM...A TRANSITION PERIOD OF WEAK RIDGING
PRIOR TO THE NEXT SIGNIFICANT FRONTAL PASSAGE. AS FAR AS THE MODEL
COMPARISON GOES...THE DEPICTION OF THE 500 MB LOW IS QUITE DIFFERENT
IN BOTH TIMING AND CHARACTER. GFS DEPICTION ISNT QUITE AS DEEP WITH
THE HEIGHT FALLS...HOW FAR SOUTH THE LOW DIPS...OR AS SIGNIFICANT IN
THE POSITIVE TILT. THE ECMWF SOLUTION WOULD BE AN EYE OPENER FOR
STORM POSSIBILITIES AS IT GENERATES A HEALTHY PRE FRONTAL
TROUGH...NEAR 60 SFC DEWPOINTS AND A PROGGED 55 KT 850 MB JET. THE
ONLY REAL AGREEMENT IS THAT THE FRONT WILL EVENTUALLY PASS THROUGH
SOMETIME AROUND 12Z SATURDAY...GIVE OR TAKE 6 HOURS...AND IT WILL
PRODUCE RAIN. BECAUSE OF THIS...THATS WHAT WAS INCLUDED IN THE
GRIDS.
&&
.OHX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
01
AREA FORECAST DISCUSSION
NWS NASHVILLE TN
553 AM CST FRI NOV 30 2012
.UPDATE...
ADJUSTED FIRST FEW HOURS OF FIRST PERIOD TEMPERATURES TO ACCOUNT
FOR STOUT LOW LEVEL INVERSION THIS MORNING. ELEVATED AREAS ARE
SEEING LOW 40S WHERE LOW LYING AREAS ARE FALLING TO THE UPPER
20S. BLENDED THESE TEMPERATURES INTO GENERAL DIURNAL WARMING
TRENDS.
&&
.PREV DISCUSSION... /ISSUED 350 AM CST FRI NOV 30 2012/
DISCUSSION...
IN THE SHORT TERM...NOT MUCH TO SPEAK OF OTHER THAN SEEING IF
IMPROVEMENTS COULD BE MADE ON THE GFS TEMP INITIALIZATION. TRENDED A
BIT ABOVE THE GUIDANCE AS IT HAS BEEN TRENDING TOWARDS BEING TOO COOL
AS OF LATE. ALSO TWEAKED THE FIRST PERIOD SKY GRIDS TO INCLUDE THE
CIRRUS SEEN ON IR SATELLITE. NAM AND RUC LAYER RH SHOWS SOME
INCREASE IN LOW LEVEL RH THIS AFTERNOON WHICH SHOULD BRING A BIT OF
CLOUD COVER ON THE CUMBERLAND SO INCLUDED THIS INTO THE SKY GRIDS.
IN THE LONG TERM...THE FOCUS RESIDES ON THE UPCOMING FRONTAL PASSAGE
THAT IS PROGGED TO REACH MIDDLE TN BY TUESDAY AFTERNOON AS INDICATED
BY THE GFS OR EVENING PER THE ECMWF. LATEST MODEL RUNS ARE REALLY
LACKING APPRECIABLE INSTABILITY AND SHEAR. WHILE DYNAMICAL FORCING
WILL BE SUFFICIENT FOR RAIN WITH A LIGHTNING STRIKE OR TWO...THE
CONFIDENCE IN WIDESPREAD TSRA IS LOW. FORECAST SOUNDINGS...WHILE
VERY MOIST...SHOW NEARLY ZERO CAPE AND EVEN SOME CIN IN PLACE DURING
PEAK HEATING TUESDAY. LOOKS LIKE LIFT WILL BE MOSTLY DYNAMICAL AND
EVEN THAT COULD BE BETTER AS 500 MB WINDS ARE ONLY IN THE 35-40 KT
RANGE. FEEL PREVIOUS FORECAST WAS PRETTY GOOD FOR POP CHANCES AND
OTHER THAN FINE TUNING SOME TIMING AND WX WORDING...NOT MUCH WAS
CHANGED. FEEL LIKE THIS WILL BE A MODERATE TO HEAVY RAINER AND NOT
MUCH ELSE.
BEYOND THIS FRONTAL SYSTEM...A TRANSITION PERIOD OF WEAK RIDGING
PRIOR TO THE NEXT SIGNIFICANT FRONTAL PASSAGE. AS FAR AS THE MODEL
COMPARISON GOES...THE DEPICTION OF THE 500 MB LOW IS QUITE DIFFERENT
IN BOTH TIMING AND CHARACTER. GFS DEPICTION ISNT QUITE AS DEEP WITH
THE HEIGHT FALLS...HOW FAR SOUTH THE LOW DIPS...OR AS SIGNIFICANT IN
THE POSITIVE TILT. THE ECMWF SOLUTION WOULD BE AN EYE OPENER FOR
STORM POSSIBILITIES AS IT GENERATES A HEALTHY PRE FRONTAL
TROUGH...NEAR 60 SFC DEWPOINTS AND A PROGGED 55 KT 850 MB JET. THE
ONLY REAL AGREEMENT IS THAT THE FRONT WILL EVENTUALLY PASS THROUGH
SOMETIME AROUND 12Z SATURDAY...GIVE OR TAKE 6 HOURS...AND IT WILL
PRODUCE RAIN. BECAUSE OF THIS...THATS WHAT WAS INCLUDED IN THE
GRIDS.
&&
.OHX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
TB12
AREA FORECAST DISCUSSION
NWS PITTSBURGH PA
558 PM EST FRI NOV 30 2012
.SYNOPSIS...
AN EASTBOUND UPPER DISTURBANCE WILL MAINTAIN MOSTLY CLOUDY SKIES
ACROSS THE UPPER OHIO VALLEY TONIGHT WHILE SOUTHWESTERLY WIND
PROVIDES MILD TEMPERATURES WHICH WILL PERSIST FOR THE WEEKEND.
PERIODIC SHOWER CHANCES CAN BE EXPECTED FOR THE FIRST HALF OF THE
NEW WEEK WITH THE ADVANCE AND PASSAGE OF A FRONTAL SYSTEM.
&&
.NEAR TERM /THROUGH SATURDAY/...
PER BLEND OF RECENT SURFACE AND SATELLITE DATA COUPLED WITH RECENT
RAP AND NAM MODEL OUTPUT...THICK ALTOCUMULUS AND CIRROPSTRATUS
CLOUDS WILL CONTINUE TO FLOW OVER THE REGION TONIGHT AS SHORTWAVE
TROUGH PROGRESSES EASTWARD. RECENT RADAR DATA ALSO INDICATES SOME
LIGHT SHOWERS...BUT THE DRY LOW LEVEL OF THE ATMOSPHERE WILL
INHIBIT ANY MEASURABLE PRECIP...HENCE...MENTION OF SPRINKLES FOR
THE EVE SHOULD SUFFICE.
OVERNIGHT LOW WERE FORECAST ABOUT 5 DEGREES ABOVE THE AVERAGES
USING GFS...NAM MOS AND RAP MODEL OUTPUT.
BETTER INSOLATION IN THE WAKE OF TONIGHTS UPPER DISTURBANCE...IN
ADDITION TO WARM ADVCTN REGIME OVR THE AREA...WILL SUPPORT
SATURDAY HIGHS APPROXIMATELY 10 TO 15 ABOVE NORMAL.
&&
.SHORT TERM /SATURDAY NIGHT THROUGH MONDAY/...
WARM TO NEUTRAL ADVCTN IN ADVN OF...AND FOLLOWING PASSAGE OF A SHORTWAVE
IN GENLY ZONAL FLOW WILL MAINTAIN CONTINUED WARMTH ACROSS THE UPPER
OHIO VALLEY FOR THE SHORT TERM PERIOD. GFS AND NAM MOS SUGGEST TEMPERATURES
MAY BE 15 TO 20 DEGREES WARMER THAN NORMAL. HOWEVER...THE RELIEF FROM
COLD WILL BE MARRED BY INCREASING SHOWER CHANCES ON SUNDAY AS MOISTURE
AND ASCENT PROFILES ARE ALSO BE IMPROVED BY THE APPROACHING SYSTEM.
&&
.LONG TERM /MONDAY NIGHT THROUGH FRIDAY/...
MODELS WERE IN GENERAL AGREEMENT ON THE OVERALL PATTERN DURING THE
LONG TERM PERIOD...BUT VARY ON TIMING. PREFERRED THE NAEFS SOLUTION
WHICH WAS SLOWER THAN THE GFS BUT SLIGHTLY FASTER THAN THE ECMWF.
A COLD FRONT WILL MOVE ACROSS THE REGION LATE TUESDAY INTO TUESDAY
NIGHT BRINGING A FEW SHOWERS. COLDER AIR MOVING IN BEHIND THE FRONT
ON WEDNESDAY...COMBINED WITH AN UPPER LEVEL TROF MOVING ACROSS THE
GREAT LAKES...COULD BRING A FEW SNOW SHOWERS TO THE FAR NORTHERN
COUNTIES DURING THE DAY...HOWEVER HIGH PRESSURE SHOULD QUICKLY BUILD
IN ENDING ANY PRECIP.
EXPECT TEMPS WEDNESDAY TO SLOWLY FALL OFF DURING THE LATE MORNING
AND AFTERNOON AS WELL WITH THE CAA. TEMPS SHOULD INCREASE TO ABOVE
NORMAL LEVELS AGAIN BY LATE IN THE WEEK.
ANOTHER COLD FRONT APPROACHES FROM THE WEST FRIDAY AFTERNOON.
&&
.AVIATION /00Z SATURDAY THROUGH WEDNESDAY/...
NO RESTRICTIONS ARE EXPECTED DURING THE TAF PERIOD ALTHOUGH MID
AND HIGH CLOUDS WILL STREAM ACRS UPR OH TERMINALS TONIGHT WITH
PASSAGE OF A CROSSING SHORTWAVE. SUSTAINED SFC WIND IS EXPECTED TO
RMN LESS THAN 10 KTS FOR THE PD.
.OUTLOOK.../SATURDAY NIGHT THROUGH WEDNESDAY/...
RESTRICTIONS WILL BE POSSIBLE SUNDAY AFTERNOON AND NIGHT...DUE TO
SHOWER FORMATION ALONG A WEAK EASTBOUND FRONT. A BETTER RESTRICTION
CHANCE WILL ACCOMPANY A STRONG COLD FRONT PASSAGE ON TUESDAY NIGHT...AND
WILL LIKELY PERSIST WITH COLD POOL CLOUDS AND SCATTERED SNOW SHOWERS
WEDNESDAY.
&&
.PBZ WATCHES/WARNINGS/ADVISORIES...
MD...NONE.
OH...NONE.
PA...NONE.
WV...NONE.
&&
$$
15
AREA FORECAST DISCUSSION
NWS PITTSBURGH PA
315 PM EST FRI NOV 30 2012
.SYNOPSIS...
EASTBOUND LOW PRESSURE ALOFT WILL PROMOTE MOSTLY CLOUDY SKIES
ACROSS THE UPPER OHIO VALLEY TONIGHT. SOUTHWEST WINDS WILL PROVIDE
MILD TEMPERATURES THIS WEEKEND. A SECOND EASTBOUND LOW PRESSURE
SYSTEM WILL BRING SHOWERS SUNDAY AFTERNOON. THEN A STRONGER
EASTBOUND LOW PRESSURE SYSTEM WILL BRING SHOWERS TUESDAY NIGHT
FOLLOWED BY A COOL DOWN WEDNESDAY.
&&
.NEAR TERM /THROUGH SATURDAY/...
PER BLEND OF RECENT SURFACE AND SATELLITE DATA COUPLED WITH RECENT
RAP AND NAM MODEL OUTPUT...CONTINUE TO EXPECT BANDS OF THICK ALTOCUMULUS
AND CIRRUS CLOUDS TO PASS EASTWARD ACROSS THE UPPER OHIO VALLEY
THROUGH TONIGHT. THESE CLOUDS ARE ASSOCIATED WITH AN EASTBOUND
TROUGH ALOFT. RECENT RADAR DATA SHOWS AN EASTBOUND BAND OF PRECIPITATION-
SIZED PARTICLES...VIRGA...ACROSS OHIO. SO HAVE MENTIONED POSSIBLE
SPRINKLES AS LOW LEVELS SHOULD REMAIN RATHER DRY.
PER RECENT GFS AND NAM MOS AND RAP MODEL OUTPUT...FORECASTED LOW
TEMPERATURES TONIGHT TO BE WARMER THAN NORMAL...BY ABOUT 5
DEGREES. EXPECT DECREASED CLOUDS SATURDAY SO HIGHS SATURDAY
AFTERNOON CAN BE 10 TO 15 DEGREES WARMER THAN NORMAL.
&&
.SHORT TERM /SATURDAY NIGHT THROUGH MONDAY/...
POST HIGH PRESSURE WILL PROMOTE MILD TEMPERATURES TO CONTINUE
ACROSS THE UPPER OHIO VALLEY THIS PERIOD. GFS AND NAM MOS SUGGEST
TEMPERATURES SUNDAY INTO MONDAY CAN BE 15 TO 20 DEGREES WARMER
THAN NORMAL.
BLEND OF RECENT SREF MODEL OUTPUT CONTINUE TO SHOW AN OCCLUDING
LOW PRESSURE SYSTEM MOVING EASTWARD THROUGH THE GREAT LAKES
SUNDAY...THAT WILL LIKELY BRING SHOWERS TO THE UPPER OHIO VALLEY
SUNDAY AFTERNOON AND EVENING. PRE-SHOWER WINDS SUNDAY AFTERNOON
CAN PRODUCE GUSTS TO 30 MPH.
&&
.LONG TERM /MONDAY NIGHT THROUGH FRIDAY/...
MODELS WERE IN GENERAL AGREEMENT ON THE OVERALL PATTERN DURING THE
LONG TERM PERIOD...BUT VARY ON TIMING. PREFERRED THE NAEFS SOLUTION
WHICH WAS SLOWER THAN THE GFS BUT SLIGHTLY FASTER THAN THE ECMWF.
A COLD FRONT WILL MOVE ACROSS THE REGION LATE TUESDAY INTO TUESDAY
NIGHT BRINGING A FEW SHOWERS. COLDER AIR MOVING IN BEHIND THE FRONT
ON WEDNESDAY...COMBINED WITH AN UPPER LEVEL TROF MOVING ACROSS THE
GREAT LAKES...COULD BRING A FEW SNOW SHOWERS TO THE FAR NORTHERN
COUNTIES DURING THE DAY...HOWEVER HIGH PRESSURE SHOULD QUICKLY BUILD
IN ENDING ANY PRECIP.
EXPECT TEMPS WEDNESDAY TO SLOWLY FALL OFF DURING THE LATE MORNING
AND AFTERNOON AS WELL WITH THE CAA. TEMPS SHOULD INCREASE TO ABOVE
NORMAL LEVELS AGAIN BY LATE IN THE WEEK.
ANOTHER COLD FRONT APPROACHES FROM THE WEST FRIDAY AFTERNOON.
&&
.AVIATION /20Z FRIDAY THROUGH WEDNESDAY/...
NO RESTRICTIONS ARE EXPECTED DURING THE TAF PERIOD. HIGH CLOUDS WILL
LIKELY BE PERSISTENT THROUGH THE NEXT 24 HOURS...WITH THE BEST
CHANCE FOR MID LEVEL CLOUDS DURING THE EVENING INTO THE OVERNIGHT
HOURS. WHILE WINDS MAY OCCASIONALLY GUST TO 15 KTS LATE THIS
AFTERNOON AND TOMORROW AFTERNOON...WINDS ARE GENERALLY EXPECTED TO
BE OUT OF THE SOUTH AT LESS THAN 10 KTS.
.OUTLOOK.../SATURDAY NIGHT THROUGH WEDNESDAY/...
RESTRICTIONS WILL BE POSSIBLE SUNDAY AFTERNOON AND NIGHT...DUE TO
SHOWERS DUE TO A WEAK EASTBOUND FRONT. A STRONG COLD FRONTAL
PASSAGE TUESDAY NIGHT WILL LIKELY BRING RESTRICTIONS DUE TO RAIN
SHOWERS TUESDAY NIGHT AND COLD POOL CLOUDS AND SCATTERED SNOW
SHOWERS WEDNESDAY.
&&
.PBZ WATCHES/WARNINGS/ADVISORIES...
MD...NONE.
OH...NONE.
PA...NONE.
WV...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS TWIN CITIES/CHANHASSEN MN
355 PM CST FRI NOV 30 2012
.DISCUSSION...
TONIGHT AND SATURDAY...A STNRY FNT WILL LINGER WELL SE OF THE AREA
OVERNIGHT INTO SATURDAY WHILE A STRENGTHENING WMFNT APPROACHES
FROM THE SW. WINDS ARE CURRENTLY UNDERGOING A SHIFT FROM E TO
SE...CONTINUING TO VEER TO S BY DAYBREAK SAT MRNG. CONCENTRATION
OF MOISTURE IN THE LOWER LEVELS BEHIND THE STNRY FNT AND AHEAD OF
THE WMFNT WILL HELP KEEP LOW STRATUS IN PLACE THROUGH AT LEAST
TMRW MRNG. IN ADDITION...AN INCREASE IN DEWPOINTS WILL HELP
PROMOTE FOG DEVELOPMENT...ESPECIALLY OVER CENTRAL-ERN MN INTO WRN
WI. NOT CONFIDENT ON THE INTENSITY OF THE FOG...INCLUDING THE
POTENTIAL FOR DENSE FOG...SO WILL KEEP ITS MENTION IN ALL
GRIDDED/TEXT PRODUCTS AND LET TRENDS DICTATE IF ANYTHING FURTHER
IS NEEDED. THE SHIFTING WINDS ALONG WITH THE SERIES OF FRONTS WILL
MAINTAIN FAIRLY STEADY TEMPS TNGT IN THE LOW-MID 30S. AS THE WMFNT
PUSHES THRU TMRW...STRONG SLY FLOW WILL BRING IN MUCH WARMER AIR
DESPITE LACK OF STRONG INSOLATION. HIGHS WILL REACH THE MID 40S TO
LWR 50S. BY LATE IN THE DAY...A SMALL BUCKLE IN THE H7-H5 FLOW
WITHIN THE INCREASING MOISTURE COLUMN OVER ERN MN-WRN WI MAY BE
ENOUGH TO PRODUCE ISOLD-SCTD RAIN SHOWERS OVER ERN PORTIONS OF THE
WFO MPX CWFA. NOT LOOKING FOR A LOT OF QPF...ONLY A FEW
HUNDREDTHS...BUT HAVE MAINTAINED POPS INTO THE HIGH-END CHC AND
EVEN LOW-END LIKELY RANGE WITH THE WARM FROPA AND A TRAILING SFC
TROUGH.
SATURDAY NIGHT THROUGH TUESDAY...THE WARM AIR WILL RESIDE OVER
THE AREA THRU THE WEEKEND INTO EARLY NEXT WEEK AS ZONAL FLOW TAKES
HOLD...PREVENTING ANY COLD AIR FROM DROPPING DOWN THRU MON. SFC
HIGH PRES WILL MOVE IN ON SUN...BRINGING TO AN END ANY LINGERING
RAIN SHOWERS OVER WRN WI LATE SAT NIGHT. HIGH PRES SHIFTS OFF TO
THE E SUN NIGHT...CREATING A STRONG PRES GRADIENT IN ADVANCE OF A
STRONG COLD FRONT FOR MID-LATE DAY MON. BREEZY CONDITIONS WILL
DEVELOP MON IN ADVANCE OF AND IMMEDIATELY FOLLOWING THE
CDFNT...AND THERE WILL BE A BRIEF SHOT OF SOME RAIN SHOWERS MAINLY
LATE DAY MON INTO MON EVE. SOME OF THE PRECIP MAY MIX WITH SNOW
SHOWERS AS CAA KICKS IN BEHIND THE CDFNT MON NIGHT INTO TUE. THOUGH
CONDITIONS WILL BE IMPROVING TUE...BRISK NW FLOW WILL REDUCE TEMPS
QUITE NOTICEABLY. HIGHS SUN-MON WILL REACH THE MID 40S TO MID
50S...FOLLOWED BY HIGHS IN THE MID 30S TO LWR 40S ON TUE.
TUESDAY NIGHT THROUGH THURSDAY...A BRIEF RESPITE OF HIGH PRES WILL
SHIFT ACRS THE AREA TUE NIGHT THRU WED...THEN A SERIES OF STRONG
SYSTEMS MOVING ONSHORE THE WRN CONUS WILL SHIFT EWD INTO THE
CENTRAL CONUS. ANOTHER STRONG TEMPERATURES SWING IS EXPECTED ALONG
WITH THE POTENTIAL FOR BOTH RAIN AND SNOW. LOTS OF UNCERTAINTY AT
THIS POINT BUT HAVE MAINTAINED CHC POPS THU INTO THU NIGHT.
&&
.AVIATION.../18Z TAF ISSUANCE/
ERLY WINDS ACROSS THE AREA HAS SLOWLY PUSHED STRATUS ACROSS ALL
MPX TERMINALS...WITH THE EDGE OF THE CLOUDS NOW STRETCHING FROM
DUBUQUE OVER TO FAIRMONT...THEN TO TRACY AND WEST TO HURON. WINDS
ARE STARTING TO BECOME MORE SRLY ALONG THE SODAK BORDER...AND AS
THIS HAPPENS...THE RAP AND NAM WOULD INDICATE THAT THESE LOW
CLOUDS SHOULD START RETREATING NORTH. HOWEVER...THE HRRR CONTINUES
TO SLOWLY NUDGE THESE CLOUDS SW DURING THE AFTERNOON AND CERTAINLY
SHOWS NO SIGNS OF CLEANING THEM OUT THIS EVENING. MAKING THE
FORECAST TRICKY FOR TONIGHT...ALL MODELS BASICALLY DRY OUT THE
925-900 MB LAYER /CURRENT CLOUD BEARING LAYER/...BUT KEEP THE ATMO
FROM 925 MB DOWN TO THE SFC NEARLY SATURATED. THIS WOULD MEAN THAT
IF WE DO NOT LOOSE CIGS THIS EVENING...THEN THEY WOULD LIKELY
START TO DESCEND AGAIN TONIGHT UNDER 1K FT...WHICH IS WHAT CURRENT
TAFS GO FOR. SOUNDINGS SHOW PLENTY OF LOW LEVEL MOISTURE FOR FOG
DEVELOPMENT...BUT WITH LOW LEVEL WINDS REMAINING AROUND 10 KTS
THROUGH THE NIGHT...MAIN RESTRICTIONS SHOULD BE THE RESULT OF LOW
STRATUS...WITH VSBYS REMAINING MVFR OR GREATER. AT ANY
RATE...AFTER THE WAY GUIDANCE PERFORMED LAST NIGHT WITH OVER DOING
THE DEVELOPMENT OF LOW STRATUS AND DZ...CONFIDENCE FOR TAFS
TONIGHT IS NOT EXACTLY GREAT.
KMSP...AS WINDS CONTINUE TO SLOWLY VEER THIS AFTERNOON TOWARD 120
AND BEYOND...CLIMATOLOGY WOULD SAY THAT CLOUD HEIGHTS SHOULD
SLOWLY START TO IMPROVE...HENCE HAVE CIGS ABOVE 017 AT 21Z. FOR
TONIGHT...FORECAST SOUNDINGS CERTAINLY SHOW LOW STRATUS STAYING PUT
AND DESCENDING...BUT CLIMATOLOGY WITH WINDS VEERING TOWARD 180
WOULD SAY THERE IS THE POTENTIAL FOR SOME IMPROVEMENT IN CLOUDS.
HOWEVER...GIVEN EXTENT OF CLOUDS TO THE SOUTH AND PRESENT FORECAST
SOUNDINGS...KEPT CLOUDS IN PLACE...WITH CONDITIONS SLOWLY DROPPING TO
IFR THROUGH THE NIGHT. MORE CONFIDENT IN SEEING CIG IMPROVEMENTS
SAT MORNING WITH WINDS CONTINUING TO VEER TOWARD 210 DEGS. BEST
SHOT FOR PRECIP LOOKS TO COME BETWEEN 18Z AND 21Z AS A WEAK
BOUNDARY SLIDES THROUGH...BUT DEEP MOISTURE IS AGAIN LIMITED...SO
LEFT ANY PRECIP MENTION OUT.
/OUTLOOK FOR KMSP/
SUN...MFVR OR LOWER CIGS EARLY. VFR BY AFTERNOON. WINDS S AT 5KTS.
MON...MVFR CIGS. CHANCE OF AFTERNOON -RA. WINDS SSW AT 10G15KTS.
SHIFTING TO THE WNW AT 15G25KTS WITH AFTERNOON FROPA.
TUE...VFR. WINDS NW AT 10G15KTS.
&&
.MPX WATCHES/WARNINGS/ADVISORIES...
MN...NONE.
WI...NONE.
&&
$$
JPC/MPG
AREA FORECAST DISCUSSION
NWS TWIN CITIES/CHANHASSEN MN
1218 PM CST FRI NOV 30 2012
.UPDATE...
18Z AVIATION DISCUSSION ADDED BELOW.
&&
.PREVIOUS DISCUSSION...
/ISSUED AT 325 AM CST FRI NOV 30 2012/
PRIMARY FORECAST CONCENTRATIONS THIS MORNING ARE THE FREEZING
DRIZZLE POTENTIAL FOR THIS MORNING...PRECIPITATION CHANCES FOR
SATURDAY...AND HIGH TEMPERATURES AND PRECIPITATION CHANCES FOR
MONDAY.
EARLY MORNING WATER VAPOR IMAGERY SHOWS A WEAK SHORTWAVE RIPPLE
TRAVERSING THE AREA...WHILE REGIONAL SURFACE OBS COLLECTIVELY
ILLUSTRATE A WEAK TROUGH FROM NEBRASKA AND IOWA TOWARD LOWER LAKE
MICHIGAN. LOW LEVEL NORTHEASTERLY FLOW HAS ALLOWED THE INFLUX OF
LOW CLOUDS FROM NORTHERN WISCONSIN INTO THE FORECAST AREA TO
COMMENCE. WHILE CEILINGS HAVE REDUCED TO AROUND 1500 FEET ACROSS
WEST CENTRAL WI AND CENTRAL MN COUNTIES /GENERALLY ALONG AND NORTH
OF INTERSTATE 94/...THE DEPTH OF THE MOISTURE IS SEEMINGLY FAIRLY
SHALLOW...AND PROGGED LIFT IS MODEST AT BEST. WILL RETAIN A BRIEF
PERIOD OF FREEZING DRIZZLE AFTER 12Z FROM CENTRAL AND EAST CENTRAL
MN ACROSS WEST CENTRAL WI...BUT ANY ACTIVITY SHOULD BE VERY LIGHT
AND TRANSITION TO THE LIQUID FORM BY LATE MORNING AS SURFACE TEMPS
RISE ABOVE FREEZING.
ALTHOUGH DIURNAL WARMING TODAY WILL BE AT A MINIMUM...THE
RELATIVELY WARM START TO THE DAY WILL SET THE STAGE FOR A MILD
DAY. HIGH TEMPERATURES WILL RANGE FROM THE MID 30S TO LOWER 40S.
MEANWHILE...A SURFACE TROUGH WILL ENTER THE DAKOTAS TODAY...AND
EJECT NORTHEAST TO NORTHWESTERN ONTARIO BY SATURDAY MORNING.
ATTENDANT MID LEVEL ENERGY WILL SPILL INTO THE AREA ON
SATURDAY AND SATURDAY NIGHT...AS THE WEAK TRAILING COLD FRONT MOVES
ACROSS THE AREA. WHILE MOISTURE MAY AGAIN BE LACKING...MODEL
AGREEMENT/CONSISTENCY IS SUFFICIENT TO SUPPORT CHANCE POPS FROM
CENTRAL MN INTO WEST CENTRAL WI...AND LOW LIKELY POPS NEAR
LADYSMITH WHERE MOISTURE IS MORE PROMISING.
HIGH PRESSURE PREVAILS ON SUNDAY IN THE WAKE OF THE TROUGH...WITH
A CONTINUANCE OF THE MILD WEATHER WITH HIGHS IN THE LOWER 40S TO
MID 50S RANGE. THE NEXT TROUGH ARRIVES ON MONDAY...WITH MOISTURE
NOT APPEARING THAT IMPRESSIVE ONCE AGAIN. HAVE RETAINED
SLIGHT/CHANCE POPS FOR MONDAY...BUT BRISK WINDS WILL PROBABLY BE
THE BIGGER HEADLINE. HAVE INCLUDED 15 TO 25 KT WINDS...WITH GUSTS
TO 35 KTS APPEARING POSSIBLE ON MONDAY AND TUESDAY. COULD SEE HIGH
TEMPS APPROACHING RECORD VALUES ON MONDAY PRIOR TO THE
FROPA...WITH 850MB TEMPS PROGGED TO INCREASE TO AROUND +11C.
YET ANOTHER WEAK SYSTEM IS PROGGED TO MOVE ACROSS THE NORTH
CENTRAL CONUS TOWARD THE END OF NEXT WEEK...PER GFS AND ECMWF
MODELS. THIS FEATURE APPEARS SLIGHTLY MORE AMPLIFIED AND
COLDER...SO SNOW HAS BEEN INTRODUCED INTO THE FORECAST FOR THE
THURSDAY-FRIDAY TIME FRAME OF NEXT WEEK.
&&
.AVIATION.../18Z TAF ISSUANCE/
ERLY WINDS ACROSS THE AREA HAS SLOWLY PUSHED STRATUS ACROSS ALL
MPX TERMINALS...WITH THE EDGE OF THE CLOUDS NOW STRETCHING FROM
DUBUQUE OVER TO FAIRMONT...THEN TO TRACY AND WEST TO HURON. WINDS
ARE STARTING TO BECOME MORE SRLY ALONG THE SODAK BORDER...AND AS
THIS HAPPENS...THE RAP AND NAM WOULD INDICATE THAT THESE LOW
CLOUDS SHOULD START RETREATING NORTH. HOWEVER...THE HRRR CONTINUES
TO SLOWLY NUDGE THESE CLOUDS SW DURING THE AFTERNOON AND CERTAINLY
SHOWS NO SIGNS OF CLEANING THEM OUT THIS EVENING. MAKING THE
FORECAST TRICKY FOR TONIGHT...ALL MODELS BASICALLY DRY OUT THE
925-900 MB LAYER /CURRENT CLOUD BEARING LAYER/...BUT KEEP THE ATMO
FROM 925 MB DOWN TO THE SFC NEARLY SATURATED. THIS WOULD MEAN THAT
IF WE DO NOT LOOSE CIGS THIS EVENING...THEN THEY WOULD LIKELY
START TO DESCEND AGAIN TONIGHT UNDER 1K FT...WHICH IS WHAT CURRENT
TAFS GO FOR. SOUNDINGS SHOW PLENTY OF LOW LEVEL MOISTURE FOR FOG
DEVELOPMENT...BUT WITH LOW LEVEL WINDS REMAINING AROUND 10 KTS
THROUGH THE NIGHT...MAIN RESTRICTIONS SHOULD BE THE RESULT OF LOW
STRATUS...WITH VSBYS REMAINING MVFR OR GREATER. AT ANY
RATE...AFTER THE WAY GUIDANCE PERFORMED LAST NIGHT WITH OVER DOING
THE DEVELOPMENT OF LOW STRATUS AND DZ...CONFIDENCE FOR TAFS
TONIGHT IS NOT EXACTLY GREAT.
KMSP...AS WINDS CONTINUE TO SLOWLY VEER THIS AFTERNOON TOWARD 120
AND BEYOND...CLIMATOLOGY WOULD SAY THAT CLOUD HEIGHTS SHOULD
SLOWLY START TO IMPROVE...HENCE HAVE CIGS ABOVE 017 AT 21Z. FOR
TONIGHT...FORECAST SOUNDINGS CERTAINLY SHOW LOW STRATUS STAYING PUT
AND DESCENDING...BUT CLIMATOLOGY WITH WINDS VEERING TOWARD 180
WOULD SAY THERE IS THE POTENTIAL FOR SOME IMPROVEMENT IN CLOUDS.
HOWEVER...GIVEN EXTENT OF CLOUDS TO THE SOUTH AND PRESENT FORECAST
SOUNDINGS...KEPT CLOUDS IN PLACE...WITH CONDITIONS SLOWLY DROPPING TO
IFR THROUGH THE NIGHT. MORE CONFIDENT IN SEEING CIG IMPROVEMENTS
SAT MORNING WITH WINDS CONTINUING TO VEER TOWARD 210 DEGS. BEST
SHOT FOR PRECIP LOOKS TO COME BETWEEN 18Z AND 21Z AS A WEAK
BOUNDARY SLIDES THROUGH...BUT DEEP MOISTURE IS AGAIN LIMITED...SO
LEFT ANY PRECIP MENTION OUT.
/OUTLOOK FOR KMSP/
SUN...MFVR OR LOWER CIGS EARLY. VFR BY AFTERNOON. WINDS S AT 5KTS.
MON...MVFR CIGS. CHANCE OF AFTERNOON -RA. WINDS SSW AT 10G15KTS.
SHIFTING TO THE WNW AT 15G25KTS WITH AFTERNOON FROPA.
TUE...VFR. WINDS NW AT 10G15KTS.
&&
.MPX WATCHES/WARNINGS/ADVISORIES...
MN...NONE.
WI...NONE.
&&
$$
LS/MPG
AREA FORECAST DISCUSSION...UPDATED AVIATION
NWS ST LOUIS MO
1201 PM CST FRI NOV 30 2012
.SHORT TERM...
ISSUED AT 350 AM CST FRI NOV 30 2012
(TODAY)
UNSEASONABLY MILD LATE AUTUMN NIGHT SHOULD BE A LEAD-IN TO AN
UNSEASONABLY WARM LATE NOVEMBER DAY FOR THE CWA...AND CLOUDS WILL BE
THE DETERIMINING FACTOR ON HOW WARM WE WILL GET THIS AFTERNOON.
MODELS ARE FORECASTING THE INCREASE IN LOW LEVEL RH TO BEGIN
TODAY...AND INDEED THE LOW CLOUD SATELLITE ENHANCEMENT HAS INDICATED
SOME CLOUDS FORMING OVER E OK AND W CENTRAL/NW AR OVER THE PAST FEW
HOURS...WITH A FEW CLOUDS ALSO JUST BEGINNING TO SHOW UP SE OF A
VIH-FAM LINE. HOWEVER... BELIEVE THIS INITIAL SURGE WILL BE FAIRLY
SHALLOW AND MAY HAVE A DIFFICULT TIME MAINTAINING A PERSISTENT CLOUD
DECK. RAP DATA SUGGESTS THAT THE BEST LOW LEVEL MOISTURE RETURN
THROUGH TODAY WILL REMAIN TO OUR S...BOTTLED UP BY THE ARKANSAS
PORTION OF THE OZARK PLATEAU/BOSTON MOUNTAINS. BASED ON THE THINKING
THAT THERE SHOULD BE A FAIR AMOUNT OF SUNSHINE TODAY HAVE ONCE AGAIN
TRENDED TO THE WARMER MET NUMBERS...WITH HIGHS RANGING FROM AROUND
60 IN FAR N/E COUNTIES OF THE CWA TO THE MIDDLE 60S ALONG AND S OF
THE I-70 CORRIDOR IN MO.
TRUETT
&&
.LONG TERM...
ISSUED AT 350 AM CST FRI NOV 30 2012
(TONIGHT THROUGH SUNDAY NIGHT)
A LOT TO DEAL WITH IN THE SHORT TERM...AS FORECAST AREA TO SEE WELL
ABOVE NORMAL TEMPERATURES THROUGH THE PERIOD...DESPITE A BIT MORE
CLOUDS OVER THE REGION THROUGH THE WEEKEND.
FOR TONIGHT...WEAK WARM FRONT TO LIFT NORTH OF FORECAST AREA...SO
ANY PATCHY FOG THAT MAY FORM OVER NORTHERN PORTIONS OF FORECAST
EARLY ON...WILL IMPROVE AS WINDS PICKUP FROM THE SOUTH.
OTHERWISE...LOWS WILL ONLY BE IN THE 40S.
THEN ON SATURDAY LOW LEVEL MOISTURE WILL CONTINUE TO BE ON THE
INCREASE AHEAD OF COLD FRONT THAT WILL SLIDE THROUGH AREA SATURDAY
NIGHT...BEFORE WEAKENING/WASHING OUT ON SUNDAY. SOME CONCERN ABOUT
STRATUS ADVECTING NORTH INTO SOUTHERN PORTIONS OF FORECAST AREA
SATURDAY MORNING AHEAD OF SYSTEM...BUT BUFKIT SOUNDINGS HAVE BRIEF
LOW CIGS WITH STRATUS THEN LIFT BY MID MORNING. SO FOR NOW HAVE NOT
ADDED MENTION OF DRIZZLE IN THIS AREA. OTHERWISE...WILL SEE SOME
LIGHT RAIN DEVELOP OVER NORTHERN PORTIONS OF FORECAST AREA AHEAD OF
COLD FRONT SATURDAY AFTERNOON. AMOUNTS WITH THIS SYSTEM WILL BE
RATHER LIGHT...SO JUST WENT WITH LOW CHANCE POPS AND LIGHT RAIN. AS
FOR TEMPS...WITH MORE CLOUDS FORECAST OVER THE REGION...LOWERED HIGH
TEMPS A FEW DEGREES...INTO THE LOW TO MID 60S.
BETTER CHANCES OF LIGHT RAIN SATURDAY NIGHT...BUT STILL NOT A LOT OF
QPF WITH FRONTAL BOUNDARY...SO KEPT LOW CHANCE POPS FOR AREAS ALONG
AND NORTH OF A STEELVILLE MO TO SPARTA IL LINE. ANOTHER MILD NIGHT
IN STORE WITH LOWS ONLY IN THE LOW TO MID 50S.
ON SUNDAY THE FRONTAL BOUNDARY WILL WASHOUT ALONG I-44 CORRIDOR...SO
SOME LINGERING LIGHT RAIN POSSIBLE ALONG AND SOUTH OF THIS AREA
DURING THE DAY...WHICH COULD LINGER INTO SUNDAY NIGHT...BUT
CONFIDENCE IS LOW...SO KEPT MENTION OUT FOR NOW. AS FOR
TEMPS...CLOUDS TO THIN OUT FOR NORTHERN PORTIONS OF FORECAST AREA
AND WINDS TO PICKUP FROM THE SOUTHWEST. SO WILL SEE NEAR RECORD
HIGHS WITH TEMPS IN THE 65 TO 70 DEGREE RANGE. MILD TEMPS TO PERSIST
SUNDAY NIGHT...WILL LOWS IN THE MID TO UPPER 50S.
(MONDAY THROUGH THURSDAY)
BY MONDAY...A MORE VIGOROUS SYSTEM TO APPROACH THE REGION WITH A
COLD FRONT SLIDING THROUGH DURING THE AFTERNOON AND EVENING HOURS.
SOME DECENT INSTABILITY...LIFT AND LOW LEVEL MOISTURE...SO SHOULD
SEE SHOWERS AND SOME THUNDERSTORMS. HIGHS ON MONDAY WILL REMAIN WELL
ABOVE NORMAL IN THE UPPER 60S TO LOW 70S...NEAR RECORD HIGHS FOR A
NUMBER OF LOCATIONS. LOWS MONDAY NIGHT WILL BE IN THE LOW 40S FAR
NORTH TO THE LOW 50S FAR SOUTHEAST.
BY TUESDAY...SHOWERS TO TAPER OFF AND COLDER AIR TO FILTER IN.
HOWEVER...NOT A LOT OF CAA WITH SYSTEM...SO TEMPS WILL STILL BE A
BIT ABOVE NORMAL...IN THE LOW 50S NORTH TO THE UPPER 50S SOUTH.
BEYOND THAT...SURFACE RIDGE TO BUILD IN WITH NEAR NORMAL TEMPS FOR
THE REST OF THE FORECAST PERIOD.
BYRD
&&
.AVIATION...
ISSUED AT 1138 AM CST FRI NOV 30 2012
PRIMARY CONCERN FOR THIS FORECAST CYCLE WILL BE STRATUS OVERSPREADING
MUCH OF THE AREA LATE TONIGHT. AM ALSO WATCHING A DEVELOPING 5000FT
DECK MOVING NORTH-NORTHEAST OVER THE OZARKS WHICH MAY ALSO IMPACT
THE AREA LATE THIS AFTERNOON. HOWEVER...NOT EXPECTING ANY CLOUDS
BELOW VFR CONDITIONS UNTIL TONIGHT. CURRENT INDICATIONS ARE THAT
STRATUS WILL MOVE FROM THE SOUTHEAST PLAINS TONIGHT AND SPREAD
NORTHEAST THROUGH MISSOURI. FEEL PRETTY CONFIDENT THERE WILL BE
CLOUDS...BUT LESS CONFIDENT IN HEIGHTS THO IFR DOES APPEAR LIKELY
OVER MUCH OF CENTRAL AND NORTHEAST MO BEFORE 12Z SATURDAY. CIGS
SHOULD BE HIGHER FURTHER EAST...BUT AS MENTIONED BEFORE AM NOT
SURE HOW MUCH HIGHER...AND WHERE THE TRANSITION FROM IFR TO MVFR
WILL BE.
SPECIFICS FOR KSTL...
PRIMARY CONCERN AT LAMBERT WILL BE DEVELOPING MVFR...POTENTIALLY
IFR CIGS LATE TONIGHT/EARLY SATURDAY MORNING. CURRENT INDICATIONS
ARE THAT CIGS BELOW 2000FT WILL STAY WEST OF THE TERMINAL...BUT
THERE IS A CHANCE THAT LOWER CONDITIONS COULD AFFECT LAMBERT. FOR
NOW IT LOOKS LIKE THE PROBABILITY OF LOW MVFR/IFR IS LESS THAN 50
PERCENT. WILL LET FOLLOWING SHIFTS TAKE ANOTHER LOOK AND
REEVALUATE AS NEEDED. CIGS SHOULD HANG AROUND FOR MOST IF NOT ALL
DAY SATURDAY.
CARNEY
&&
.CLIMATE...
ISSUED AT 504 PM CST WED NOV 28 2012
ABOVE NORMAL TEMPERATURES ARE FORECAST THIS WEEKEND. HERE ARE THE
RECORD HIGH AND HIGH MINIMUM TEMPERATURES FOR THE FIRST THREE DAYS
OF DECEMBER FOR THE CITIES OF ST. LOUIS...COLUMBIA...AND QUINCY.
RECORD HIGH TEMPERATURES...
ST. LOUIS COLUMBIA QUINCY
SATURDAY 12/1 73F (1970) 68F (1982) 67F (1913)
SUNDAY 12/2 74F (1982) 72F (1917) 67F (1982)
MONDAY 12/3 76F (1970) 72F (1998) 71F (1970)
RECORD HIGH MINIMUM TEMPERATURES...
ST. LOUIS COLUMBIA QUINCY
SATURDAY 12/1 53F (1980) 53F (1921) 52 (1913)
SUNDAY 12/2 63F (1982) 59F (1982) 59 (1982)
MONDAY 12/3 62F (1998) 58F (1998) 59 (1998)
&&
.LSX WATCHES/WARNINGS/ADVISORIES...
MO...NONE.
IL...NONE.
&&
$$
WFO LSX
AREA FORECAST DISCUSSION...UPDATED
NWS NASHVILLE TN
1005 AM CST FRI NOV 30 2012
.UPDATE...FOR 18Z AVIATION DISCUSSION.
&&
.AVIATION...18Z AVIATION DISCUSSION.
SFC RIDGING INFLUENCES WILL CONTINUE TO PLAY MAJOR ROLE IN WX
THRU 01/18Z...WITH SFC PRESSURE GRADIENT CONTINUING TO HOLD.
WEAK DISTURBANCES ALOFT MIGHT BRING SOME SCT/BKN CI THRU TIME
PERIOD ALSO. ANTICIPATE CURRENT STRATO CU BKN CEILINGS NEAR CSV
TO DISSIPATE BEFORE OR SLIGHTLY AFTER 30/18Z PER ATM MIXING
INFLUENCES BECOMING BETTER ESTABLISHED.
&&
.PREV DISCUSSION.../ISSUED 842 AM CST FRI NOV 30 2012/
UPDATE...UPDATED ZONE PACKAGE TO ACCOUNT FOR CURRENT CLOUD CONDITIONS
AND TRENDS.
PREV DISCUSSION.../ISSUED 626 AM CST FRI NOV 30 2012/
UPDATE...FOR 12Z AVIATION FORECAST
AVIATION...
STRATOCUMULUS ARE MOVING NORTH FROM ALABAMA BASED AROUND 25 HNDRD
FEET MSL. THESE CLOUDS APPEAR TO BE RIDING ALONG THE 290 KELVIN
SURFACE ON A SOUTHWESTERLY 30 KNOT LOW LEVEL JET. EXPECT THESE
CLOUDS TO BE AROUND THROUGH 14Z-15Z TIME FRAME OR UNTIL MIXING CAN
GET UNDERWAY...THEN THEY SHOULD THIN OUT. OTHERWISE LOOK FOR VFR
CONDITIONS TO PREVAIL THROUGH THE NEXT 24 HOURS WITH WINDS BECOMING
GUSTY DURING THE DAY AS SURFACE PRESSURE GRADIENT TIGHTENS A BIT
FROM CAROLINA HIGH PRESSURE CENTER TO OUR EAST AND CENTRAL PLAINS
LOW. EXPECT WIND GUSTS TO 18 KNOTS DURING THE DAY WITH WINDS
SUBSIDING BY EARLY EVENING.
BOYD
PREV DISCUSSION... /ISSUED 350 AM CST FRI NOV 30 2012/
DISCUSSION...
IN THE SHORT TERM...NOT MUCH TO SPEAK OF OTHER THAN SEEING IF
IMPROVEMENTS COULD BE MADE ON THE GFS TEMP INITIALIZATION. TRENDED A
BIT ABOVE THE GUIDANCE AS IT HAS BEEN TRENDING TOWARDS BEING TOO COOL
AS OF LATE. ALSO TWEAKED THE FIRST PERIOD SKY GRIDS TO INCLUDE THE
CIRRUS SEEN ON IR SATELLITE. NAM AND RUC LAYER RH SHOWS SOME
INCREASE IN LOW LEVEL RH THIS AFTERNOON WHICH SHOULD BRING A BIT OF
CLOUD COVER ON THE CUMBERLAND SO INCLUDED THIS INTO THE SKY GRIDS.
IN THE LONG TERM...THE FOCUS RESIDES ON THE UPCOMING FRONTAL PASSAGE
THAT IS PROGGED TO REACH MIDDLE TN BY TUESDAY AFTERNOON AS INDICATED
BY THE GFS OR EVENING PER THE ECMWF. LATEST MODEL RUNS ARE REALLY
LACKING APPRECIABLE INSTABILITY AND SHEAR. WHILE DYNAMICAL FORCING
WILL BE SUFFICIENT FOR RAIN WITH A LIGHTNING STRIKE OR TWO...THE
CONFIDENCE IN WIDESPREAD TSRA IS LOW. FORECAST SOUNDINGS...WHILE
VERY MOIST...SHOW NEARLY ZERO CAPE AND EVEN SOME CIN IN PLACE DURING
PEAK HEATING TUESDAY. LOOKS LIKE LIFT WILL BE MOSTLY DYNAMICAL AND
EVEN THAT COULD BE BETTER AS 500 MB WINDS ARE ONLY IN THE 35-40 KT
RANGE. FEEL PREVIOUS FORECAST WAS PRETTY GOOD FOR POP CHANCES AND
OTHER THAN FINE TUNING SOME TIMING AND WX WORDING...NOT MUCH WAS
CHANGED. FEEL LIKE THIS WILL BE A MODERATE TO HEAVY RAINER AND NOT
MUCH ELSE.
BEYOND THIS FRONTAL SYSTEM...A TRANSITION PERIOD OF WEAK RIDGING
PRIOR TO THE NEXT SIGNIFICANT FRONTAL PASSAGE. AS FAR AS THE MODEL
COMPARISON GOES...THE DEPICTION OF THE 500 MB LOW IS QUITE DIFFERENT
IN BOTH TIMING AND CHARACTER. GFS DEPICTION IS-NT QUITE AS DEEP WITH
THE HEIGHT FALLS...HOW FAR SOUTH THE LOW DIPS...OR AS SIGNIFICANT IN
THE POSITIVE TILT. THE ECMWF SOLUTION WOULD BE AN EYE OPENER FOR
STORM POSSIBILITIES AS IT GENERATES A HEALTHY PRE FRONTAL
TROUGH...NEAR 60 SFC DEWPOINTS AND A PROGGED 55 KT 850 MB JET. THE
ONLY REAL AGREEMENT IS THAT THE FRONT WILL EVENTUALLY PASS THROUGH
SOMETIME AROUND 12Z SATURDAY...GIVE OR TAKE 6 HOURS...AND IT WILL
PRODUCE RAIN. BECAUSE OF THIS...THATS WHAT WAS INCLUDED IN THE
GRIDS.
&&
.OHX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
31
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