Forecast Discussions mentioning any of
"HRRR" "RAP" "RR" "RUC13" "RUC" received at GSD on 01/11/13
AREA FORECAST DISCUSSION
NWS TUCSON AZ
900 PM MST THU JAN 10 2013
.SYNOPSIS...A STRONG LOW PRESSURE SYSTEM WILL CONTINUE THE GUSTY
WINDS TONIGHT...WITH A GOOD CHANCE OF VALLEY RAIN AND HIGHER
ELEVATION SNOW TONIGHT INTO FRIDAY MORNING. EXPECT SHARPLY COLDER
TEMPERATURES AND MAINLY DRY CONDITIONS THIS WEEKEND INTO EARLY NEXT
WEEK...WITH WIDESPREAD HARD FREEZE CONDITIONS OVER SEVERAL DAYS.
&&
.DISCUSSION...SHOWERS STARTING TO INCREASE WITH A NARROW MOISTURE
TAP BEING DRAWN INTO THE FRONTAL DYNAMICS FROM THE SOUTHWEST AS IT
PUSHES THROUGH SOUTHEAST ARIZONA THIS EVENING. ALSO NOTING SECONDARY
LOW LEVEL CONVERGENCE AND HEIGHT FALLS IN EASTERN AREAS AHEAD OF
MAIN FRONTAL BAND. BASED ON CURRENT AND HRRR TRENDS WE MADE
ADJUSTMENTS EARLIER TO INCREASE THE CHANCE OF SHOWERS (ESPECIALLY IN
MOUNTAIN LOCATIONS) AND SPREAD UPSLOPE ENHANCED SHOWERS FURTHER EAST
A LITTLE QUICKER THIS EVENING. INCREASED MOUNTAIN SNOW ACCUMULATIONS
IN FIRST PERIOD AS WELL BUT KEPT THINGS BELOW ADVISORY LEVELS...IN
THE 3 TO 6 INCH RANGE. WIND ADVISORY DOING WELL IN COCHISE
COUNTY...WATCHING TRENDS IN OTHER AREAS CLOSELY ESPECIALLY MOUNTAIN
ZONES.
ALSO WENT AHEAD AND PUSHED THE HARD FREEZE WATCH TO A HARD FREEZE
WARNING WITH NO SIGNIFICANT SURPRISES FROM THE 00Z NAM AS IT STARTED
TO ROLL IN.
&&
.PREV DISCUSSION...WIND SPEEDS HAVE INCREASED A BIT THIS AFTERNOON
WITH FURTHER INCREASE LIKELY THIS EVENING AS PRESSURE GRADIENT PEAKS
IN ADVANCE OF APPROACHING COLD FRONT. STRONGEST WINDS WILL BE MOSTLY
IN COCHISE COUNTY...WHERE WE MAINTAIN THE CURRENT TIMING OF WIND
ADVISORY BETWEEN 6 PM TONIGHT AND 3 AM FRIDAY. THE ONLY CHANGE I
REALLY MADE TO THE FORECAST WAS TO SHOW BETTER TIMING OF SHOWERS
MOVING ACROSS THE AREA IN ADVANCE OF COLD FRONT. DOWNSCALED NAM AND
HRRR MODELS WERE USED IN THIS DEPICTION. COLD FRONT IS PROGGED TO
MOVE THROUGH TUCSON BETWEEN 11 PM AND 1 AM. EVENING SHIFT LIKELY
WILL MAKE SOME MORE MODIFICATIONS AS THE FRONT PUSHES EAST ACROSS
THE AREA. SNOW LEVELS FALLING DOWN TO AROUND 3000 FEET BUT DON`T
EXPECT MUCH ACCUMULATION AT THE LOWER ELEVATIONS...WITH MAYBE UP TO
FOUR INCHES ABOVE 6000 FEET...ESPECIALLY IN THE WHITES.
TURNING MUCH COLDER BEHIND COLD FRONT WITH UNSEASONABLY COLD
TEMPERATURES AREA WIDE FOR AN EXTENDED PERIOD OF TIME...LIKELY INTO
NEXT TUESDAY. OVERNIGHT LOWS WILL BE VERY COLD FOR OUR NECK OF THE
CACTI WITH WIDESPREAD FREEZING TEMPERATURES. WE CONTINUE TO MAKE
SMALL CHANGES TO SHOW COLDER LOWS. WILL MAINTAIN HARD FREEZE WATCH
FOR THE LOW DESERTS OF SOUTHEAST ARIZONA SATURDAY MORNING THROUGH
MONDAY MORNING. THIS WATCH WILL LIKELY BE UPGRADED TO WARNING IN THE
NEXT 24 HOURS.
TROFINESS REMAINS DURING THE FIRST HALF OF NEXT WEEK WHICH WILL
BRING A SLIGHT CHANCE OF LIGHT PRECIPITATION TO MOSTLY THE EASTERN
ZONES.
&&
.AVIATION...SCT-BKN 6-8KFT AGL WITH SCT -SHRA/-SHSN UNTIL 11/15Z.
SFC WND SWLY 15-25 KTS WITH PK WND NEAR 40 KTS...BECOMING WLY AND
NWLY AND DIMINISHING BEHIND FROPA. AVIATION DISCUSSION NOT UPDATED
FOR TAF AMENDMENTS.
&&
.FIRE WEATHER...GUSTY WINDS TONIGHT INTO FRIDAY MORNING WITH A GOOD
CHANCE OF RAIN AND MOUNTAIN SNOW SHOWERS. DRY CONDITIONS WITH MUCH
COLDER TEMPERATURES WILL OCCUR THIS WEEKEND INTO EARLY NEXT WEEK.
&&
.CLIMATE...4 CONSECUTIVE DAYS IN A ROW OF HIGHS LESS THAN 50 DEGREES
IN TUCSON IS POSSIBLE FRIDAY THROUGH MONDAY. THIS WOULD BE THE FIRST
TIME SINCE JANUARY 1971 THAT A CONSECUTIVE STRETCH OF 4 OR MORE DAYS
WITH HIGHS BELOW 50 HAS OCCURRED. THERE HAVE BEEN SEVEN TOTAL TIMES
IN THE TUCSON CLIMATE RECORD OF HIGHS BELOW 50 FOR 4 OR MORE
CONSECUTIVE DAYS. THE LONGEST STRETCH OF DAYS BELOW 50 DEGREES IS 5
DAYS AND THIS HAS HAPPENED THREE TIMES IN TOTAL WITH THE LAST
OCCURRENCE IN JANUARY 1971. IN RECENT TIMES...THE LONGEST STRETCH IS
3 DAYS BACK IN JANUARY 1997 WHICH WE HAVE HIGH CONFIDENCE WILL OCCUR
THIS YEAR.
MEANWHILE...RECORD LOW MAX TEMPERATURES ARE GENERALLY IN THE LOW TO
MID 40S FOR TUCSON WITH SATURDAY BEING 44 DEGREES WHICH IS ALSO THE
CURRENT FORECAST HIGH TEMPERATURE. RECORD LOWS ARE GENERALLY IN THE
UPPER TEENS TO LOWER 20S. WE WILL BE ESPECIALLY CLOSE TO THE RECORD
LOW ON SUNDAY MORNING OF 22 DEGREES AS THE CURRENT FORECAST IS FOR
23 DEGREES.
EVEN THOUGH THIS WILL BE A SIGNIFICANT COLD OUTBREAK IT DOES NOT
LOOK LIKE IT WILL BE QUITE AS EXTREME AS OUR MOST RECENT COLD BLAST
IN FEBRUARY 2011 FOR COLD TEMPERATURES. THIS TIME AROUND WE EXPECT
TEMPERATURES TO MEET THE HARD FREEZE THRESHOLD OF 28 DEGREES OR
LOWER FOR ABOUT 6 TO 8 HOURS CONSECUTIVELY EACH NIGHT. COMPARE THIS
TO FEBRUARY 2011 WHEN TEMPERATURES WERE IN HARD FREEZE TERRITORY FOR
10 TO 14 HOURS IN A ROW FOR 2 NIGHTS. IN ADDITION...TEMPERATURES
WILL WARM UP INTO THE 40S DURING THE DAY COMPARED TO THE PEAK OF THE
FEBRUARY 2011 EVENT WHEN THE HIGH WAS 38 DEGREES IN TUCSON. ALTHOUGH
NOT EXPECTED TO BE AS EXTREME AS FEBRUARY 2011...THIS WILL STILL BE
A MAJOR COLD OUTBREAK THAT WILL LAST LONGER THAN FEBRUARY 2011 WITH
DEFINITE NEED TO TAKE THE SAME PRECAUTIONS.
&&
.TWC WATCHES/WARNINGS/ADVISORIES...
HARD FREEZE WARNING FROM LATE FRIDAY NIGHT THROUGH MONDAY MORNING
FOR AZZ501-502-504>506.
WIND ADVISORY UNTIL 3 AM MST FRIDAY FOR AZZ507-508-512-513.
&&
$$
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MEYER/CERNIGLIA/GLUECK
AREA FORECAST DISCUSSION
NWS EUREKA CA
437 AM PST WED JAN 9 2013
.SYNOPSIS...A COLD FRONT WILL BRING A QUICK SHOT OF RAIN THIS
MORNING. SNOW LEVELS WILL FALL RAPIDLY THIS AFTERNOON BEHIND THE
FRONT AS SHOWERS AND ISOLATED THUNDERSTORMS IMPACT THE REGION. ANOTHER
DISTURBANCE WILL MAINTAIN SHOWER ACTIVITY INTO THE WEEKEND BEFORE
A BUILDING UPPER LEVEL RIDGE BRINGS DRIER WEATHER TO THE REGION EARLY
NEXT WEEK.
&&
.DISCUSSION...SAT IMAGERY SHOWS UPPER TROUGH MOVG PAST 130W EARLY
THIS MORNING WITH PLENTY OF OPEN CELL CU BEHIND THE ASSOCIATED
COLD FRONT. RADAR SHOWS LGT RETURNS NEAR THE ORCA BORDER WITH SFC
OBS ALREADY REPORTING INTERMITTENT LGT PRECIP NEAR THE COAST.
PERIODS OF -RA WILL CONTINUE UNTIL THE FRONT ARRIVES. EXPECT FRONT
TO MOVE INTO DEL NORTE COUNTY AROUND SUNRISE AND PUSH S AND E
THROUGH THE MORNING...EXITING CWA THIS AFTERNOON. A BRIEF BREAK
IN CLOUDS AND PRECIP BEHIND THE FRONT BEFORE SHOWERS ARRIVE LATER
THIS MORNING AND AFTERNOON. FCST SOUNDINGS CONTINUE TO SHOW
FAVORABLE DYNAMICS FOR SMALL HAIL AND ISOLD TSTMS THIS AFTERNOON
THROUGH THU MORNING. SN LEVELS INITIALLY ABOVE 5KFT THIS MORNING
WILL FALL RAPIDLY BEHIND THE FRONT AS THE ASSOCIATED COLD UPPER
TROUGH APPROACHES THE REGION. SNOW LEVELS WILL FALL TO 2500 FT BY
THIS AFTERNOON AND TO 1000 FT BY THU MORNING AS THE COLD AIRMASS
SETTLES OVER THE REGION. SHOWER ACTIVITY WILL PEAK THIS EVENING
AND OVERNIGHT AS THE TROUGH AXIS CROSSES THE REGION. RAPIDLY
FALLING SNOW LEVELS COMBINED WITH CONVECTIVE NATURE OF THE PRECIP
MAKE THE MAIN FCST CHALLENGE SNOW ACCUMULATIONS. CONTINUED TO
TREND FCST TOWARDS THE HIGHER EC AND SREF QPF SOLNS RESULTING IN
HIGHER SNOW AMT FCST. EXPECT 3-7 INCH ACCUMULATIONS IN ZONES 3
AND 4 WITH 6-10 INCHES WITH LOCALIZED AMOUNTS TO 12-15 INCHES ABOVE
3KFT...SO EXPANDED WINTER WX ADVISORY TO INCLUDE TRINITY COUNTY.
HEAVIEST PRECIP AND HIGHEST SNOW ACCUMULATIONS WILL BE ACROSS THE
SISKIYOU AND SOUTH FORK RANGES. LIGHTER ACCUMULATIONS EXPECTED
OVER MENDOCINO COUNTY WHERE 1-3 INCHES EXPECTED ABOVE 1500 FT
THROUGH THU MORNING. UPPER RIDGE WILL BEGIN TO BUILD OVER THE NE
PAC THU RESULTING IN UPPER FLOW BECOMING NLY ACROSS THE REGION.
PRECIP CHCS WILL DIMINISH AND SHIFT SLIGHTLY OFFSHORE THU
AFTERNOON AS A RESULT. A COUPLE OF MINOR PERTURBATIONS IN THE NLY
FLOW WILL MAINTAIN ISOLD TO SCT SHOWER ACTIVITY MAINLY N OF CAPE
MENDO INTO THE WEEKEND. MODELS CONTINUE TO SHOW UPPER RIDGE
SHIFTING ONSHORE EARLY NEXT WEEK...BUT 09/00Z MODELS SLOWED THIS
SLIGHTLY COMPARED TO PREV RUNS. HOWEVER...MADE LITTLE CHANGE TO
THE EXTENDED AS WARMER TEMPS AND DRIER WX EXPECTED ACROSS THE
REGION EARLY NEXT WEEK.
&&
.AVIATION...COLD FRONT APPEARS TO BE WITHIN 3 TO 5 HOURS OF
CROSSING THE NORTH COAST PER RUC ANALYSIS AND SATELLITE IMAGERY.
CIGS ARE STILL BELOW 1000FT AT KACV BUT ARE BEGINNING TO COME UP
WITH INCREASED MIXING AHEAD OF THE FRONT...JUST VFR CONDITIONS AT
KACV. EXPECT A FEW HOURS OF IMPROVED CONDITIONS BEFORE THE FRONT
ARRIVES. 2 TO 4 MI VSBYS MAY LAST AN HOUR OR SO WITH A PERIOD OF
RAIN ALONG THE COLD FRONT 15-17Z AT KACV/KCEC...A COUPLE HOURS
LATER AT KUKI. NOT EXPECTING SIGNIFICANT REDUCED VSBYS AT KUKI
TODAY THOUGH WITH LIGHTER SHOWER ACTIVITY SOUTH OF CAPE MENDOCINO.
WINDS WILL SHIFT TO THE NW IN THE WAKE OF THE FRONT BUT EXPECT
GUSTS TO BE MAINLY 15 KT OR LESS. SHOWERS LATE TODAY AND TONIGHT
WILL LIKELY CONTAIN SMALL HAIL WITH BRIEF TSRA POSSIBLE AND
TEMPORARY IFR CIGS/VSBYS POSSIBLE IN THE HEAVIER SHOWERS.
CONDITIONS WILL IMPROVE ON THURSDAY. AAD
&&
.MARINE...CANCELLED HAZ SEAS WARNING FOR THE OUTER WATERS TODAY
BUT LEFT SCA RUNNING THROUGH AT LEAST FRI MORNING. BEGINNING TO
SEE LONGER PERIOD WAVES SHOW UP 9-10 FT AT 13-14 SECS. BUOY 2
NEARING 15 FT WHICH IS AT OR JUST BELOW FCST HEIGHTS. SWAN IS
COMING IN A TOUCH LOWER AS WELL...AND WINDS ARE NOT EXPECTED TO BE
QUITE AS HIGH IN THE WAKE OF THE FRONT AND WILL TEND TO SUBSIDE
FOR AWHILE TONIGHT. NOT TO SAY THAT CONDITIONS WILL NOT BE POOR
ACROSS THE OUTER WATERS WITH SCT HEAVY SHOWERS AND ISOLATED
THUNDERSTORMS WITH SMALL HAIL AROUND...ALONG WITH 15-25 KT NW
WINDS ON TOP OF BUILDING MODERATE LONG-PERIOD SEAS. THESE SEAS
WILL ONLY TEND TO BUILD FURTHER THROUGH THURDAY. NRLY GRADIENT
WILL INCREASE AS WELL RESULTING IN WIDESPREAD 15-25 KT WINDS. EVEN
SOME GALE FORCE GUSTS LIKELY BEYOND 8-10 NM. THIS WOULD PUT
CONDITIONS SOLIDLY IN HAZ SEAS FOR TOMORROW BUT WILL LET THE DAY
SHIFT MAKE THE CALL ON WHETHER OR NOT TO HOIST A WARNING. LONG
PERIOD SEAS WILL DECAY AND SUBSIDE THROUGH THE WEEKEND BUT
MODERATE NORTHERLY WINDS 10-20 KT AND STEEPER SHORT PERIOD SEAS
WILL TEND TO PERSIST. AAD
&&
.COASTAL FLOODING...ANOTHER ROUND OF HIGH ASTRONOMICAL TIDES
EXPECTED THIS WEEK. FCST HIGH TIDES OF 8.4FT TODAY...AND 8.6FT
THU AND FRI. FCST ANOMALIES CONTINUE TO RUN SLIGHTLY LOWER THAN
FCST...INCREASING SLY WINDS EARLY THIS MORNING FOLLOWED BY FRONTAL
PASSAGE WILL LIKELY SHIFT ANOMALIES TO SLIGHTLY ABOVE FCST.
ALTHOUGH NO FLOODING IS ANTICIPATED ATTM...WILL CONTINUE TO
MONITOR FOR POTENTIAL IMPACTS...ESPECIALLY FOR THU AND FRI HIGH
TIDES.
&&
.EKA WATCHES/WARNINGS/ADVISORIES...
WINTER WEATHER ADVISORY FROM 4 PM THIS AFTERNOON TO 4 AM PST
THU ABOVE 1500 FEET FOR CAZ004.
WINTER WEATHER ADVISORY FROM 1 PM THIS AFTERNOON TO 10 AM PST THU
ABOVE 1500 FEET FOR CAZ003.
SMALL CRAFT ADVISORY UNTIL 9 AM PST FRI FOR PZZ450-470.
SMALL CRAFT ADVISORY UNTIL 3 PM PST FRI FOR PZZ455-475.
&&
$$
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AREA FORECAST DISCUSSION
NWS PUEBLO CO
247 PM MST WED JAN 9 2013
.SHORT TERM...
(TONIGHT AND TOMORROW)
...MAIN SHORT TERM CONCERN IS THE CHANCE OF RAIN AND FREEZING RAIN
ACROSS THE FAR SE PLAINS...
CURRENT WATER VAPOR IMAGERY AND UPPER AIR ANALYSIS INDICATING WEAK
MAINLY WESTERLY FLOW ALOFT ACROSS THE AREA WITH A LARGE UPPER LOW
STILL SPINNING ACROSS NORTHEASTERN MEXICO JUST SOUTH AND WEST OF DEL
RIO TEXAS AT THIS TIME. WATER VAPOR IMAGERY INDICATING MID AND UPPER
LEVEL MOISTURE ASSOCIATED WITH THIS SYSTEM SPREADING NORTH INTO
EASTERN NEW MEXICO AND WESTERN TEXAS...WITH MID AND UPPER LEVEL
MOISTURE ALSO SPREADING INTO THE GREAT BASIN REGION AHEAD OF A
DEVELOPING STORM SYSTEM MOVING ONSHORE ACROSS THE PAC NW COAST AT
THIS TIME. WITH THE LIGHT WINDS...TEMPERATURES HAVE STRUGGLED TO
WARM WITH READINGS IN THE MID 40S TO LOWER 50S ACROSS THE LOWER
ELEVATIONS AND 20S AND 30S ACROSS THE HIGHER ELEVATIONS. TEMPS IN
THE SAN LUIS VALLEY CONTINUE TO LAG BEHIND WITH READINGS MAINLY IN
THE TEENS AND 20S...WITH THE COLDEST READINGS IN THE CENTRAL
PORTIONS OF THE VALLEY.
TONIGHT...MODELS STILL DIFFER ON LOCATION OF EJECTING LOW WITH THE
12Z GFS AND EC THE FURTHEST NORTH AND WEST WITH THE LOW NORTH OF
ABILENE TEXAS AT 12Z THU...WHERE AS THE HIGHER RES NAM AND RAP KEEP
THE LOW FURTHER SOUTH AND EAST. THE FURTHER NORTH SOLUTIONS OF THE
EC AND ESPECIALLY THE GFS ARE INDICATING STRONGER MID LEVEL WAA
ACROSS THE WESTERN TX AND OKLAHOMA PANHANDLE THROUGH EASTERN
COLORADO AND WESTERN KANSAS AND ARE PRINTING OUT MORE QPF ACROSS THE
FAR SOUTHEAST PLAINS AS A RESULT. THE HIGHER RES MODELS KEEP THE
BEST LIFT AND WAA FURTHER EAST ACROSS WESTERN AND CENTRAL KANSAS
WHICH IS ALSO SUPPORTED BY LOCAL HIGH RES WRF MODEL. WITH THAT
SAID...HAVE KEPT CURRENT FORECAST TRENDED TOWARDS THE HIGHER RES
MODELS KEEPING SILENT POPS THROUGH 06Z WITH CHANCE POPS ACROSS
EASTERN PORTIONS OF BACA AND PROWERS COUNTIES AND SLIGHT POPS
FURTHER NORTH AND WEST INTO KIOWA AND WESTERN PROWERS AND BACA
COUNTIES THEREAFTER. SOUNDINGS INDICATING MAINLY LIGHT RAIN ACROSS
BACA COUNTY THOUGH DO INDICATE A BRIEF PERIOD OF LIGHT FREEZING RAIN
POSSIBLE ACROSS PROWERS AND KIOWA COUNTIES...WITH LATER SHIFTS
NEEDING TO MONITOR LATEST MODELS AND TRENDS. ELSEWHERE...WEAK
WESTERLY FLOW THIS EVENING BECOMES MORE SOUTHWEST AND SLOWLY
INCREASES OVERNIGHT AS EASTERN PACIFIC SYSTEM CONTINUES TO MOVE
ONSHORE ACROSS THE WEST COAST. MAINLY CLEAR SKIES WEST OF THE PLAINS
WILL HELP COOL TEMPS ONCE AGAIN IN THE SAN LUIS VALLEY...WITH THE
WARMEST READINGS EXPECTED ACROSS THE HIGHER TERRAIN ALONG AND WEST
OF THE I-25 CORRIDOR WHERE LEE TROUGHING DEVELOPS OVERNIGHT.
TOMORROW...SOUTHWEST FLOW ALOFT CONTINUES TO INCREASE THROUGH THE
DAY AS THE WEST COAST SYSTEM TRANSLATES INTO THE GREAT BASIN.
MOISTURE PROGGED TO INCREASE FROM WEST TO EAST AND WITH INCREASING
OROGRAPHICS COULD SEE SOME LIGHT SNOW DEVELOPING ACROSS THE HIGHER
TERRAIN OF THE SOUTHWEST MTS BY THE LATE AFTERNOON. LEE TROUGHING
STRENGTHENS ACROSS THE I-25 CORRIDOR WITH BREEZY SOUTH TO SOUTHWEST
WINDS DEVELOPING ACROSS THE PLAINS BOOSTING TEMPS INTO THE LOWER TO
MID 50S. INCREASING CLOUDS AND SLIGHT COOLING ALOFT WILL LEAD TO
SLIGHTLY COOLER TEMPS ACROSS THE HIGHER TERRAIN AND HIGH VALLEYS.
.LONG TERM...
(THURSDAY NIGHT THROUGH WEDNESDAY)
...HIGH IMPACT WEATHER TO AFFECT PORTIONS OF SOUTH CENTRAL AND
SOUTHEAST COLORADO THURSDAY NIGHT THROUGH FRIDAY...WITH A TURN
TOWARDS MUCH COLDER TEMPERATURES THROUGH THE WEEKEND INTO EARLY NEXT
WEEK...
A CLOSED UPPER LOW CARVES OUT ACROSS THE GREAT BASIN THURSDAY NIGHT
SENDING STRONG SOUTHWEST FLOW...WITH 110-120+ KT UPPER JET ACROSS
COLORADO BY 12Z FRIDAY. MOISTURE DEEPENS ALONG THE CONTINENTAL
DIVIDE THURSDAY EVENING...WITH SNOW RAMPING UP ALONG THE
OROGRAPHICALLY FAVORED EASTERN SAN JUAN MOUNTAINS. COMBINED WITH
MTN TOP WINDS OF 50-60 KTS...HAZARDOUS CONDITIONS WILL BE POSSIBLE
DUE TO WHITE OUT CONDITIONS IN BLOWING SNOW ACROSS ZONE 68...WHICH
INCLUDES THE WOLF CREEK PASS. HAVE UPGRADED THE WINTER STORM WATCH
TO A BLIZZARD WATCH FOR THIS ZONE. SNOW SHOULD SPREAD NORTH AND
EASTWARD AFTER MIDNIGHT THROUGH THE MORNING HOURS...WITH THE
HEAVIEST SNOW EXPECTED TO FALL BEFORE 18Z WHEN BEST FORCING MOVES
THROUGH. WINDS THEN SHIFT MORE FROM THE WEST TO NORTHWEST FRIDAY
AFTERNOON...WITH THE FOCUS FOR SNOW SHIFTING INTO THE EASTERN
SAWATCH AND WESTERN MOSQUITO RANGES DURING THE AFTERNOON. OVERALL
SNOWFALL AMOUNTS FOR THE BRUNT OF THE EVENT...THURS
NIGHT/FRI...SHOULD RANGE FROM 8 TO 17 INCHES ACROSS THE EASTERN SAN
JUAN MOUNTAINS...WITH AROUND 5 TO 10 INCHES WITH LOCALLY UP TO A
FOOT FOR THE LA GARITAS...EASTERN SAWATCH AND WESTERN MOSQUITO
RANGES. THINK THAT THESE LATTER AREAS WILL EVENTUALLY NEED A WINTER
WEATHER ADVISORY...BUT SINCE SNOW AMOUNTS HAVE BEEN CONSISTENTLY
COMING UP SHORT OF WARNING NUMBERS (12" OR MORE IN GREATER THAN 12
HOURS)...NO WATCHES WILL BE ISSUED AT THIS POINT.
AS THE UPPER JET TRANSLATES ACROSS THE AREA THURSDAY NIGHT THROUGH
FRIDAY...A BORA COLD FRONT WILL MOVE FROM WEST TO EAST ACROSS THE
REGION. HIGHER PEAKS SHOULD START BLOWING FIRST AS MTN TOP WINDS
INCREASE TO AROUND 50-60 KTS. THERE IS QUITE A BIT OF FORWARD SHEAR
WITH THIS SYSTEM...SO THIS DOESN`T APPEAR TO BE A MTN WAVE EVENT.
HOWEVER AS THE NORTH-SOUTH ORIENTED COLD FRONT CROSSES THE
MOUNTAINS...IT COULD BRING A PERIOD OF STRONG GUSTY WINDS INTO THE
ADJACENT LOWER ELEVATIONS OF THE SAN LUIS VALLEY AND THE I-25
CORRIDOR EARLY FRIDAY MORNING AS COLD DENSE AIR SPILLS OVER THE
MOUNTAINS. SFC PRESSURE GRADIENT IS IMPRESSIVE FRIDAY MORNING AS
THE SURFACE LOW DEEPENS ACROSS NORTHEAST COLORADO WHICH SHOULD ALSO
AID IN MIXING STRONG WINDS ALOFT TO THE SURFACE ACROSS THE REMAINDER
OF THE SOUTHEAST PLAINS. ALREADY HAVE A HIGH WIND WATCH OUT AND PLAN TO
MAINTAIN IT. DID BUMP UP THE START TIME OF THE HIGH WIND WATCH TO
MIDNIGHT ACROSS THE SOUTHEAST MTS AS WINDS ALOFT WILL BE INCREASING
AFTER MIDNIGHT...THOUGH THINK STRONGER GUSTS WILL STAY ACROSS THE
HIGHER ELEVATIONS UNTIL FRIDAY MORNING WHEN THE FRONT MOVES THROUGH. WINDS
MAY COME UP JUST SHY OF HIGH WIND CRITERIA ACROSS CENTER PORTIONS OF
THE SAN LUIS VALLEY...BUT VALLEY EDGES...PARTICULARLY ON THE WESTERN
SIDE COULD SEE A PERIOD OF HIGH WINDS FRIDAY MORNING.
BROAD TROFFING REMAINS ACROSS THE GREAT BASIN AND ROCKIES REGION
THROUGH EARLY NEXT WEEK AS ENERGY CONTINUES TO DROP SOUTHWARD OUT OF
CANADA. THIS WILL KEEP VERY COLD AND GENERALLY UNSETTLED CONDITIONS
ACROSS THE REGION THROUGH EARLY NEXT WEEK. TEMPERATURES WILL DROP
OFF CONSIDERABLY ACROSS THE PLAINS...WITH HIGHS STRUGGLING TO REACH
THE 30S BY THE MIDDLE OF NEXT WEEK. MEANWHILE...THE MOUNTAINS AND
VALLEYS WILL BE DROPPING INTO THE NEGATIVE DIGITS AT NIGHT...WITH
KALS LIKELY TO HIT -30 OR BELOW AS A NEW BATCH OF COLD AIR GETS
ENTRENCHED IN THE VALLEY. NEXT WAVE OF ENERGY LIFTS OUT OF THE MEAN
TROF ACROSS SOUTHERN PORTIONS OF THE AREA SAT NIGHT...AND WITH
SHALLOW UPSLOPE AND COLD AIR...WE COULD SEE SOME ADDITIONAL LIGHT
SNOW ACROSS THE MOUNTAINS AND ADJACENT PLAINS...BUT EACH SUCCESSIVE
MODEL RUN HAS BEEN DRIER...SO WILL LEAVE THE SILENT POPS ACROSS THE
PLAINS...WITH GENERALLY ISOLATED TO LOW END SCATTERED POPS ACROSS
THE MOUNTAINS. SAME THING HAPPENS FOR MONDAY NIGHT AS ANOTHER WAVE
OF ENERGY DROPPING INTO THE BASE OF THE TROF CLOSES OFF AN UPPER LOW
ACROSS THE DESSERT SOUTHWEST AND LEADING SHORTWAVE ENERGY EJECTS TO
THE NORTHEAST ACROSS THE AREA. ONCE AGAIN...IF IT OCCURS...ANY
SNOWFALL ACCUMULATIONS APPEAR TO REMAIN LIGHT. GFS AND ECMWF ORPHAN THE
UPPER LOW ACROSS EXTREME SOUTHERN AZ/NRN OLD MEXICO THROUGH
WEDNESDAY WHICH IS TOO FAR SOUTH TO BRING ANY PRECIPITATION TO THE
AREA THROUGH WEDNESDAY. TEMPERATURES SHOULD SLOWLY MODERATE SOME
INTO THE MIDDLE OF NEXT WEEK. -KT
&&
.AVIATION...
VFR CONDITIONS TO PREVAIL AT KCOS AND KPUB THROUGH THE NEXT 24
HOURS WITH GENERALLY LIGHT WINDS THROUGH TONIGHT. BREEZY SOUTH TO
SOUTHWEST WINDS OF 15-20KTS ARE EXPECTED TO DEVELOP AFT 18Z THU.
KALS HAD STRONG RADIATIONAL COOLING AND SCT001 TO LOCALLY BKN001
ACROSS THE VALLEY FLOOR LATE LAST NIGHT AND EARLY THIS MORNING...BUT
VIS DID NOT DROP BELOW MFVR. WOULD THINK THE SAME FOR TONIGHT...AS
TEMPS DID NOT WARM AS MUCH AS EXPECTED. AT ANY RATE...VFR CONDITIONS
EXPECTED THROUGH 06Z THU...WITH LOCAL IFR AND LIFR CIGS THEN
POSSIBLE THROUGH 16Z. VFR AGAIN AFT 16Z THU. -MW
&&
.PUB WATCHES/WARNINGS/ADVISORIES...
HIGH WIND WATCH FROM FRIDAY MORNING THROUGH FRIDAY AFTERNOON FOR
COZ069>071-083>089-093>099.
HIGH WIND WATCH FROM LATE THURSDAY NIGHT THROUGH FRIDAY
AFTERNOON FOR COZ072>082.
BLIZZARD WATCH FROM THURSDAY EVENING THROUGH FRIDAY AFTERNOON
FOR COZ068.
&&
$$
23/31
AREA FORECAST DISCUSSION
NWS DENVER/BOULDER CO
935 AM MST WED JAN 9 2013
.UPDATE...
&&
.SHORT TERM...LATEST LAPS SURFACE ANALYSIS SHOWING LOW PRESSURE
BEGINNING TO DEVELOP ALONG THE FRONT RANGE IN RESPONSE TO UPPER
LOW OVER MEXICO AND UPPER TROUGH MOVING INTO THE PACIFIC
NORTHWEST. GUSTY SOUTHWESTERLY HAVE DEVELOPED ACROSS MUCH OF THE
PLAINS...ROUGHLY AREAS SOUTH OF INTERSTATE 70. WILL NEED TO
INCREASE WINDS ACROSS PLAINS A BIT FOR THIS AFTERNOON. WINDS STILL
EXPECTED TO INCREASE THIS EVENING AS BOUNDARY LAYER SOUTHEAST
GRADIENT STRENGTHENS. REST OF FORECASTS LOOK ON TRACK FOR NOW.
.AVIATION...GUSTY SOUTHWEST WINDS HAVE DEVELOPED ACROSS DEN DUE TO
THE DEVELOPMENT OF SURFACE LOW PRESSURE ALONG THE FRONT RANGE. THE
GUSTY WINDS SHOULD CONTINUE INTO THE EVENING. WILL CONTINUE THE
TREND OF THE LATEST TAFS FOR THE UPCOMING ISSUANCE. LATEST HRRR
AND TO A LESSER EXTENT THE RAP SHOW A WEAK BOUNDARY MOVING INTO
THE DENVER AREA AROUND 00Z...WEAKENING THE SOUTHERLY WINDS. NOT
SURE IF THIS BOUNDARY WILL AFFECT DEN...AND WILL WAIT TO SEE WHAT
DEVELOPS.
&&
.PREV DISCUSSION... /ISSUED 329 AM MST WED JAN 9 2013/
SHORT TERM...UPPER LOW TRACKING SLOWLY NORTHEASTWARD OVER WRN
TEXAS/WRN OKLA DURING THE NEXT 24 HOURS WILL SEND HIGH CLOUDS
NORTHWARD OVER SOUTHERN AND EASTERN SECTIONS OF THE FORECAST AREA
DURING THE DAY. OTHERWISE MID-LEVEL SUBSIDENCE AND A DRIER NWLY
FLOW ALOFT SHOULD KEEP SKIES GENERALLY CLEAR FOR THE REMAINDER OF
THE FCST AREA AND TEMPERATURES ABOVE AVERAGE TODAY. THE HIGH MTN
VALLEYS SHOULD ALSO SEE TEMPERATURE READINGS MODERATE TODAY AS
THE STG SFC BASED INVERSIONS OF THE PAST SEVERAL DAYS CONTINUE TO
WEAKEN...ALLOWING WARMER AIR ALOFT TO MIX DOWN. HIGHS TODAY ON
THE PLAINS GENERALLY 8-12 DEG F ABOVE AVERAGE. AVERAGE HIGH AT
DENVER THIS TIME OF YEAR IS 44F. NEXT...MODELS PARTICULARLY THE
NAM SHOW SOUTHERLY SFC/BNDRY LAYER WINDS INCREASING ON THE PLAINS
DURING THE AFTERNOON WITH PRESSURE FALLS TO OUR NORTH. STRONGEST
WINDS...IN THE 15-25 KT RANGE...SHOULD DEVELOP ROUGHLY EAST OF A
STERLING TO ELBERT/KIOWA LINE. OVERNIGHT...FURTHER STRENGTHENING
OF THESE SOUTH-SOUTHEASTERLY SFC/BNDRY LAYER WINDS IS FORECASTED.
MODELS ALSO INDICATE AN INCREASE IN MID AND HIGH LEVEL MOISTURE
OVER FAR EASTERN SECTIONS OF THE CWFA AS THE UPPER LOW PASSES TO
OUR SOUTHEAST. THE GUSTY WINDS SHOULD KEEP THE BNDRY LAYER
ADEQUATELY MIXED RESULTING IN WARMER OVERNIGHT TEMPERATURES IN
THIS AREA.
LONG TERM...SW FLOW ALOFT WILL BE OVER THE AREA ON THU AHEAD OF
AN UPPER LEVEL TROUGH OVER THE WRN US. SFC LOW PRESSURE WILL
DEVELOP FM SERN WY INTO ERN CO WITH DOWNSLOPE FLOW EAST OF THE
MTNS. ALTHOUGH SOME MID AND HIGH LEVEL MOISTURE WILL INCREASE BY AFTN
IT SHOULD BE DRY ACROSS THE RGN. ONE MORE MILD DAY WILL OCCUR OVER
NERN CO WITH READINGS IN THE LOWER TO MID 50S EXCEPT OVER THE FAR
NERN CORNER WHERE READINGS WILL BE MAINLY IN THE UPPER 40S.
FOR THU NIGHT INTO FRI THE UPPER LEVEL TROUGH WILL BEGIN TO MOVE
EASTWARD WITH AN UPPER LEVEL LOW OVER SWRN WY BY FRI AFTN.
MEANWHILE SFC LOW PRES WILL INTENSIFY OVER ERN CO AS A CDFNT MOVES
NR THE WY-CO BORDER BY 12Z. CROSS-SECTIONS SHOW SWLY FLOW IN THE
MTNS THRU FRI AFTN WITH THE BEST CHC OF SNOW IN ZNS 31 AND 33 SO
THAT IS WHERE I WILL HAVE THE HIGHEST POPS. OVER NERN CO LATEST
00Z RUNS ARE NOT AS FAVORABLE FOR SNOW LATE FRI AFTN INTO FRI
EVENING AS 12Z RUNS WERE DUE TO LESS MOISTURE...LACK OF QG
ASCENT AND WEAKER UPSLOPE. HOWEVER LAPSE RATES ARE STILL FCST NR
8 C/KM FRI EVENING SO IF MOISTURE IS MORE LIKE 12Z RUNS THEN THERE
COULD STILL BE A PERIOD OF SNOW SO WILL LEAVE IN CHC POPS FOR LATE
FRI AFTN INTO FRI EVENING. AS FOR HIGHS ON FRI OVER NERN CO THE
FNTL BNDRY IS SLOWER AS COMPARED TO THE 12Z RUNS. AT THIS POINT
WILL KEEP HIGHS IN THE 30S EXCEPT OVER SRN LINCOLN COUNTY WHERE
READINGS MAY GET INTO THE 40S.
BY LATE FRI NIGHT THE UPPER LEVEL TROUGH WILL EXIT THE RGN AS A
SECOND FEATURE MOVES SE INTO THE AREA ON SAT. ALTHOUGH THERE IS
ONLY SOME WK QG ASCENT THRU THE DAY LAPSE RATES WILL STILL BE
RATHER UNSTABLEL SO EXPECT SOME LIGHT SNOW IN THE MTNS. OVER NERN
CO AM NOT COMPLETELY CONVINCED ITS GOING TO BE PCPN FREE
ESPECIALLY IN AND NR THE FOOTHILLS WHERE WEAK UPSLOPE FLOW WILL
EXIST AS A SECONDARY SURGE OF COLDER AIR MOVES IN. THUS WILL KEEP
IN SOME LOW POPS MAINLY WEST OF I-25. HIGHS ON SAT WILL GENERALLY
RANGE FROM 15-20 DEGREES OVER NERN CO.
FOR SUN THRU MON BOTH THE ECMWF AND GFS SHOWS A BROAD UPPER LEVEL
TROUGH OVER THE RGN ALTHOUGH TO SOME EXTENT THEY SHOW A SECONDARY
UPPER LEVEL LOW DEVELOPING OVER THE GREAT BASIN SUN NIGHT INTO MON
AS ANOTHER SURGE OF COLDER AIR MOVES INTO NERN CO. THE ECMWF IS
MUCH DRIER THAN THE GFS BOTH DAYS AND WOULD ONLY HAVE A SLIGHT CHC
OF SNOW IN THE MTNS. ON THE OTHER HAND THE GFS HAS MORE MOISTURE
ESPECIALLY SUN NIGHT INTO MON WHICH WOULD LEAD TO A CHC OF SOME
LIGHT SNOW IN THE MTNS AND ALONG THE FRONT RANGE. CONSIDERING HOW
VASTLY DIFFERENT THE MOISTURE FIELDS ARE IN THE MODELS FOR NOW
WILL ONLY MENTION A SLIGHT CHC OF SNOW IN THE MTNS. TEMPS WILL
CONTINUE WELL BLO NORMAL BOTH SUN AND MON WITH READINGS OVER NERN
CO STILL HAVING A HARD TIME GETTING ABV 20 DEGREES.
AVIATION...VFR CONDITIONS ANTICIPATED AT DENVER AREA AIRPORTS AND
SOUTH-SOUTHEAST WINDS OF 7-14KTS AT DIA AND APA FOR THE NEXT 24
HOURS. MEANWHILE LIGHT SLY BREEZES AT BJC THIS MORNING ARE
EXPECTED TO BECOME EAST-NORTHEAST AT SPEEDS UNDER 10 KTS THIS
AFTERNOON WITH THE FORMATION OF A WEAK DENVER CYCLONE ON THE
NORTH SIDE OF THE METRO AREA. OVERNIGHT...THERE IS A CHANCE THAT
DIA AND APA COULD SEE SOUTH-SOUTHEAST WINDS OF 15-22KTS SOMETIME
BETWEEN 04Z-10Z ACCORDING TO THE FCST MODELS SHOULD THE CORE OF
STRONGEST SLY WINDS ON THE PLAINS SHIFT FARTHER WEST THAN
EXPECTED.
&&
.BOU WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...D-L
LONG TERM....RPK
AVIATION...D-L
AREA FORECAST DISCUSSION
NWS MOUNT HOLLY NJ
335 PM EST WED JAN 9 2013
.SYNOPSIS...
WEAK COLD FRONT SWINGS THROUGH THE REGION LATE TONIGHT INTO THURSDAY
MORNING. HIGH PRESSURE RE-ESTABLISHES ITSELF ACROSS THE AREA ON
THURSDAY AND SLOWLY MOVES OFF TO THE EAST THROUGH THE WEEKEND.
ANOTHER LOW PRESSURE SYSTEM WILL BEGIN TO IMPACT THE REGION LATE ON
SUNDAY AS IT PUSHES ITS ASSOCIATED COLD FRONT THROUGH THE AREA BY
MONDAY. THE FRONT SHOULD DROP TO OUR SOUTH ON TUESDAY AND WEDNESDAY
AS HIGH PRESSURE FILLS BACK IN.
&&
.NEAR TERM /UNTIL 6 AM THURSDAY MORNING/...
THE GFS INITIALIZATION LOOKED BETTER THAN THE WRF-NMMB AND THERMAL
FIELDS WERE USED MORE SO THAN THE WRF-NMMB WHICH WAS COLDER THROUGH
THURSDAY.
THE JET STREAK AND A SHORT WAVE WAS ENOUGH TO GENERATE SOME
SPRINKLES AROUND OUR CWA. HRRR HAS A GOOD HANDLE ON RADAR ECHOES AND
WAS USED INTO EARLY THIS EVENING.
THE SHORT WAVE EXITS QUICKLY AND BASED ON UPSTREAM SATELLITE
IMAGERY, WE DO CLEAR THE SKIES QUICKLY THIS EVENING. THE WRF-NMMB
DOES TRAP MOISTURE UNDERNEATH THE DEVELOPING INVERSION WHICH BRINGS
BACK SHADES OF LAST WEEK. BUT UNLIKE LAST WEEK, WE ARE NOT SEEING
ANY UPSTREAM STRATOCU AND THE LOW HEIGHT OF THE INVERSION IS WELL
WITHIN THE DOWNSLOPING FLOW. ONE AREA OF CONCERN IS FAR NORTH WHERE
SOME LAKE EFFECT FLOW SHOULD OCCUR TONIGHT. RIGHT NOW THE TRAJECTORY
IS NORTHEAST OF OUR CWA.
THERE COULD BE SOME GUSTINESS, IN PARTICULAR THIS EVENING AS THE
FRONT MOVES THROUGH. BUT AS JANUARY EVENINGS GO, THIS IS NEARLY
SEASONAL. FOR MIN TEMPS A STAT GUIDANCE COMPROMISE WAS USED.
BOUNDARY LAYER WINDS SHOULD BE STRONG ENOUGH TO PREVENT TOTAL
DECOUPLING.
&&
.SHORT TERM /6 AM THURSDAY MORNING THROUGH 6 PM THURSDAY/...
AS JANUARY DAYS GO, UNLESS ONE IS LOOKING FOR SNOW, THURSDAY SHOULD
BE PRETTY PRETTY GOOD. THE NEXT HIGH PRESSURE SYSTEM WILL BE NEARING
AND THE RIDGE AXIS IS FORECAST TO STILL BE WEST OF OUR CWA. THE
FORECAST CONVECTIVE TEMPERATURE IS BEYOND REACH. WE ARE ONLY
EXPECTING SOME CIRRUS. VERY SHALLOW COLD, OK COOLER, AIR IN PLACE
FOR THE DAY. THE FORECAST WINDS ARE NOT EXPECTED TO BE THAT STRONG
AND NEITHER IS THE JANUARY SUN. SO THROUGH THE DAY, THE INVERSION
SHOULD HOLD AND WE WERE CONSERVATIVE WITH MAX TEMPS, LEANING TOWARD
A STAT GUIDANCE COMPROMISE. FULL SUN MACROS OFF THE GFS SOUNDINGS
SUPPORT NAM MOS MORE THAN GFS MOS.
&&
.LONG TERM /THURSDAY NIGHT THROUGH WEDNESDAY/...
5-WAVE MODEL GUIDANCE SHOWS THAT THE DOMINANT SOUTHEAST RIDGE VERY
SLOWLY FLATTENS OUT BY MID NEXT WEEK. THIS IS DUE TO DEEPER CENTRAL
UNITED STATES LONGWAVE TROUGHING AS A MASSIVE RIDGE BUILDS INTO THE
PACIFIC NORTHWEST.
HIGH PRESSURE RETURNS FOR A TIME PERIOD ON FRIDAY WHILE THE ONCE
STRONG SOUTHWEST CUT-OFF LOW EJECTS TOWARDS THE NORTHEAST AND
PASSES THROUGH THE GREAT LAKES. HAVING LOST ITS PHASING WITH A
NORTHERN STREAM SYSTEM AND UNABLE TO SUPPORT ITSELF ANY FURTHER, THE
LOW IS FORCED TO OPEN UP AS IT TRIES, BUT FAILS, TO CUT INTO THE TOP
OF THE EAST COAST RIDGE. IT THEN GETS PICKED UP BY THE 170KT JET
OVERHEAD AND IS SWEPT THROUGH THE NORTHEAST. DEPENDING ON HOW MUCH
REMAINING MOISTURE IS INVOLVED WITH THIS SYSTEM DICTATES HOW FAST WE
CAN SATURATE THE COLUMN AND SEE AN ACCUMULATING PRECIPITATION.
TEMPERATURES ACROSS THE NORTH WILL BE BELOW FREEZING FOR A FEW HOURS
DURING THE FORECASTED ONSET OF PRECIPITATION, I.E. FREEZING RAIN IS
POSSIBLE. THERE WAS AN EVENT MUCH LIKE THIS ABOUT A MONTH AGO WHERE
THE COLD AIR AT THE SURFACE WAS ERODED PRIOR TO ANY PRECIPITATION
FALLING DUE TO A VERY DRY COLUMN. THIS ONE LOOKS TO BE TRENDING IN
THE SAME DIRECTION ALTHOUGH NOT WITH THE TEMPERATURES RISING
OVERNIGHT BUT RATHER THE P-TYPE ISSUES.
BY LATE FRIDAY MORNING OUR SURFACES TEMPERATURES WILL ALL BE ABOVE
FREEZING WITH MORE RAIN ON THE WAY UP FROM THE SOUTHWEST...NORTHERN
ZONES HAVE THE HIGHEST CHANCES. THIS SHORTWAVE THEN SKIRTS OFF TO
THE NORTHEAST LATE FRIDAY NIGHT AND THE SOUTHEAST RIDGE
RE-ESTABLISHES ITSELF ALONG THE EAST COAST. THIS KEEPS A STRONG
SOUTHWESTERLY SURGE ALOFT ULTIMATELY ALLOWING TEMPERATURES TO CLIMB
WELL ABOVE NORMAL ON SATURDAY AND SUNDAY. THIS ALSO KEEPS MOST, IF
NOT ALL, THE SHORTWAVE ENERGY TO OUR NORTHWEST HEADING INTO SOUTHERN
ONTARIO. THE NEXT CHANCE OF PRECIPITATION WILL BE ON SUNDAY INTO
MONDAY AS A STRONGER COLD FRONT DROPS THROUGH FROM THE NORTHWEST.
THE SOUTHEAST RIDGE SHOULD KEEP THE FRONT FROM TRAVELING TOO FAR TO
OUR SOUTH. THIS WILL ALLOW THE BAROCLINIC ZONE TO FUNNEL A FEW MORE
PIECES OF ENERGY THROUGH OUR REGION ON TUESDAY AND WEDNESDAY. THE
MID-LEVEL FLOW TURNS A BIT MORE ZONAL AND THIS WILL ALLOW SOME
COLDER AIR TO BLEED INTO THE REGION FROM THE NORTHWEST...THOUGH WE
ARE NOT LOOKING AT A SUBSTANTIAL COOL DOWN BY ANY MEANS, MORE OF A
RETURN TO SLIGHTLY ABOVE NORMAL TEMPERATURES. IF TEMPERATURES CAN
COOL ENOUGH ALOFT ON WEDNESDAY WE COULD SEE A CHANGE OVER FROM RAIN
TO SNOW SHOWERS FALLING AS FAR SOUTH AS THE LEHIGH VALLEY. ALTHOUGH
WE WILL REMAIN MILD THROUGH A LOT OF THE EXTENDED WE WILL ALSO
REMAIN UNSETTLED.
&&
.AVIATION /20Z WEDNESDAY THROUGH MONDAY/...
THE FOLLOWING DISCUSSION IS FOR KPHL, KPNE, KTTN, KABE, KRDG, KILG,
KMIV, KACY AND SURROUNDING AREAS.
THE 18Z TAFS CONTINUED THE PREDOMINATELY VFR FORECAST. WE DID NOT
FOLLOW ONE OF OUR COMPUTER MODELS THAT DEVELOPS AN IFR STRATUS
CIG AROUND MIDNIGHT TONIGHT.
FOR THIS AFTERNOON, A MID LEVEL CIG WILL CONTINUE TO MOVE ACROSS THE
TERMINALS. WINDS ALOFT ARE INCREASING AND WE START SOME GUSTINESS
TOWARD EVENING. THERE COULD BE SOME SPRINKLES AT THE TERMINALS, NO
VSBY RESTRICTIONS EXPECTED FROM THEM. BUT THE FOG AND HAZE HAS BEEN
TOUGH TO DISLODGE FROM KABE AND KRDG, THE MIXING HAS NOT COME TO
FRUITION.
THE COLD FRONT WILL MOVE THROUGH THE TERMINALS EARLY THIS
EVENING. WE ARE EXPECTING GUSTINESS FROM THE WEST AND NORTHWEST
AROUND ITS PASSAGE TIME AND IN THE COLD AIR ADVECTION BEHIND IT
FOR A COUPLE OF HOURS. PEAK GUSTS SHOULD BE 15 TO 20 KTS. THERE
SHOULD BE ENOUGH MIXING TO PREVENT LLWS CONDITIONS. WINDS AT 2K
ARE FORECAST TO AVERAGE 40KT. SKIES SHOULD CLEAR.
WE ARE NOT FORECASTING GUSTS OVERNIGHT. THE NEW AND FRESHER
COLDER AIR MASS WILL PREVENT FOG FROM FORMING ON THURSDAY MORNING.
THEN, EXCELLENT VFR CONDITIONS ARE FORECAST FOR THURSDAY MORNING
INTO EARLY AFTERNOON WITH ONLY A FEW CIRRUS CLOUDS AND LIGHT
NORTHWEST WINDS.
OUTLOOK...
THURSDAY NIGHT - FRIDAY MORNING...VFR.
FRIDAY - FRIDAY NIGHT...RAIN DEVELOPING EARLY IN THE DAY. MVFR AND
IFR CONDITIONS POSSIBLE WITHIN THE RAIN.
SATURDAY - SUNDAY...VFR.
SUNDAY NIGHT - MONDAY...RAIN DEVELOPING EARLY MONDAY MORNING. MVFR
OR LOWER POSSIBLE WITHIN SHOWERS.
&&
.MARINE...
THE SCA WILL BE CONTINUED FOR TONIGHT AS IS. HIGHER CONFIDENCE ON
THE NORTHERN OCEANIC WATERS THAN THE SOUTHERN WATERS AND LOWER
DELAWARE BAY. THE CHANCES FOR SCA CONDITIONS LESSEN TOWARD AND
DEFINITELY DURING THURSDAY MORNING. RIGHT NOW THE ADVISORY
EXPIRATION IS PRETTY CLOSE AND WE WILL LEAVE IT AS IS. MIGHT NEED A
SLIGHT TIME EXTENSION EAST OF DELAWARE BAY.
THE REST OF THURSDAY WILL BE SPENT WITH SUB SMALL CRAFT ADVISORY
CRITERIA AS THE HIGH PRESSURE SYSTEM GETS CLOSER.
OUTLOOK...
SUB-ADVISORY CONDITIONS ARE EXPECTED ACROSS OUR WATERS THROUGH THE
OUTLOOK PERIOD. THOUGH IT WILL BE AN ACTIVE PERIOD WITH MULTIPLE
SYSTEM PASSING THROUGH A LARGE SOUTHEAST UNITED STATES HIGH PRESSURE
SYSTEM WILL FORCE THESE SYSTEMS FAR TO OUR NORTH. THIS WILL KEEP THE
PRESSURE GRADIENT RATHER WEAK SO NOT EXPECTING WINDS AND SEAS TO
JUMP MUCH THROUGH THE PERIOD. WINDS WILL PREDOMINANTLY BE FROM THE
NORTH ON FRIDAY BEFORE SHIFTING TOWARDS THE SOUTH FOR THE WEEKEND
AND EARLY NEXT WEEK.
&&
.PHI WATCHES/WARNINGS/ADVISORIES...
PA...NONE.
NJ...NONE.
DE...NONE.
MD...NONE.
MARINE...SMALL CRAFT ADVISORY UNTIL 6 AM EST THURSDAY FOR ANZ431-
450>455.
&&
$$
SYNOPSIS...HEAVENER
NEAR TERM...GIGI
SHORT TERM...GIGI
LONG TERM...HEAVENER
AVIATION...GIGI/HEAVENER
MARINE...GIGI/HEAVENER
AREA FORECAST DISCUSSION
NWS TALLAHASSEE FL
1117 AM EST Wed Jan 9 2013
.UPDATED...
Clouds and fog held in longer than expected this morning so
forecast max temps have been nudged down 2-3 degrees.
.NEAR TERM [Through Rest of Today]...
The large scale split flow long wave pattern remains highly
amplified especially across Srn stream. This is highlighted in Nrn
stream by ridging over Wrn states, trough over Wrn most Great Lakes
and ridging over Ern seaboard into adjacent Atlc. Srn stream
highlighted by trough over Srn plains with closed low over NE old
Mex and Srn TX and ridging over se region into Wrn Atlc.
At surface, morning analysis shows a low near TX with cold front swd
into SE TX, and W-E warm front extending Ewd across FL Gulf Coast.
Warm front is well defined, separating a moist tropical airmass over
the Nrn Gulf from a modified continental one that has been in place
across the SE. Dew points just S of front in low to mid 60s. It was
also responsible for generating area of fog, sprinkles and drizzle
along and north of it across our land area. Inverted coastal trough
also noted just off NE FL coast.
During the rest of today, NRN stream trough will move quickly across
Great Lakes region then Ewd towards NE states in response to next
trough that begins to dig SEWD across extreme Ern PAC into West
coast. TX low will shift NEWD across rest of TX (and eventually into
Lwr MS Valley) generating widespread convection. In response,
SE ridge builds NWD. The combination of NRN trough and lifting TX
low will accelerate cold front across TX and lift warm front NWD,
However main forcing will remain well to our west in the vicinity of
cold front. This front will also signal the beginning of a warm and
humid pattern that will last into much of next week. It will also
lift coastal trough NEWD as local winds veer.
Even with all the cloudiness and some sprinkles and drizzle in place
this morning, expect enough breaks in the cloud cover into the aftn
to support temperatures in the low to mid 70s. Latest guidance and
satellite pix suggest cloud/fog erosion from E-W next few hours. So
even though 14z-15z temps running 3-5 degrees below forecast max,
they should rebound some into aftn so won`t make any updates at this
time but monitor closely. So areas in the SE Fl Big Bend could also
get into the mid-upper 70s should more breaks develop in the
overcast. The increasingly warm and moist onshore flow moving over
cooler shelf waters of Gulf will likely continue to generate
sea fog over the marine area and adjacent coast. This is evident in
the local NAM DNG5, other guidance and satellite pix. This
reflected in latest GRIDS.
&&
.SHORT TERM [Tonight Through Friday]...
With the warm front lifting northward through the area by tonight,
the region will be in an increasingly more humid airmass, which
will likely support the formation of fog/stratus after midnight.
Temperatures will also be noticeably warmer with lows around 60
degrees.
Starting Thursday the storm system across Central Texas will
begin to move north northeast around a building mid level ridge
centered over the Florida Peninsula. As this system moves into the
Great Lakes, a weak cold front will move eastward across the
Central Gulf States. The strengthening ridge will slow the
eastward progress of this system as the main upper level energy
continues to move quickly northward. As a result, only low end
rain chances are expected Thursday night into Friday as this front
eventually dissipates across the region.
As was much the case in the near term period, the short term
period will have unseasonably warm temperatures with highs in the
low to mid 70s in the western areas (due to more cloud cover) and
in the upper 70s to near 80 in the east. Overnight lows will be
muggy by January standards, generally in the upper 50s to lower 60s.
&&
.LONG TERM [Friday Night through Tuesday]...
There is good agreement between the GFS and ECMWF that deep layer
ridging will be the dominant synoptic feature over the Southeast.
This correlates to a continuation of above-average temperatures (at
least 10 to 15 degrees warmer than climatology) away from the
beaches (where SSTs remain in the upper 50s to lower 60s). The PoP
will be in the 10 to 30% range- highest along and left of a line
from Albany to Panama City as that region will be closer to the Q-G
forcing and deep layer moisture associated with a persistent
quasi-stationary frontal system.
&&
.AVIATION [through 18z Thursday]...
Updated at 950 am EST-
MVFR cigs will persist across our area (except IFR in fog and light
rain especially at KECP and KVLD until early afternoon. Then, most
cigs will lift to high MVFR, but IFR cigs may persist all day at
KECP. Widespread LIFR (or worse) Vis & cigs are likely tonight,
beginning near the coast shortly after sunset, then spreading inland
later tonight. Our forecast is a blend of the GFS/NAM MOS and latest
HRRR, with emphasis on the HRRR (which has verified well so far this
morning) through this afternoon.
&&
.MARINE...
The pressure gradient will remain tight across the marine area as a
low pressure area lifts northward across Texas and high pressure
persists over the NE gulf. Cautionary level winds will continue
possibly into Thursday before relaxing. Lighter onshore flow is
expected by the weekend as high pressure builds just off the Florida
Peninsula.
&&
.FIRE WEATHER...
Relative humidity levels will remain too moist for red flag
conditions for at least the remainder of this week.
&&
.HYDROLOGY...
No appreciable rainfall amounts are expected through the next few
days.
.PRELIMINARY POINT TEMPS/POPS...
Tallahassee 75 61 77 59 74 / 10 10 10 20 20
Panama City 71 64 74 63 73 / 20 10 10 40 20
Dothan 71 61 75 62 75 / 30 10 10 30 20
Albany 72 60 75 62 75 / 20 10 10 20 20
Valdosta 76 61 78 60 78 / 10 10 10 10 20
Cross City 79 59 79 58 76 / 10 10 10 10 20
Apalachicola 69 64 70 63 70 / 10 10 10 30 20
&&
.TAE WATCHES/WARNINGS/ADVISORIES...
FL...None.
GA...None.
AL...None.
GM...None.
&&
$$
NEAR TERM...Block
SHORT TERM...Godsey
LONG TERM...Fournier
AVIATION...Block
MARINE...Block/Godsey
FIRE WEATHER...Fournier
HYDROLOGY...Godsey
AREA FORECAST DISCUSSION
NWS TALLAHASSEE FL
1007 AM EST Wed Jan 9 2013
.NEAR TERM [Through Rest of Today]...
The large scale split flow long wave pattern remains highly
amplified especially across Srn stream. This is highlighted in Nrn
stream by ridging over Wrn states, trough over Wrn most Great Lakes
and ridging over Ern seaboard into adjacent Atlc. Srn stream
highlighted by trough over Srn plains with closed low over NE old
Mex and Srn TX and ridging over se region into Wrn Atlc.
At surface, morning analysis shows a low near TX with cold front swd
into SE TX, and W-E warm front extending Ewd across FL Gulf Coast.
Warm front is well defined, separating a moist tropical airmass over
the Nrn Gulf from a modified continental one that has been in place
across the SE. Dew points just S of front in low to mid 60s. It was
also responsible for generating area of fog, sprinkles and drizzle
along and north of it across our land area. Inverted coastal trough
also noted just off NE FL coast.
During the rest of today, NRN stream trough will move quickly across
Great Lakes region then Ewd towards NE states in response to next
trough that begins to dig SEWD across extreme Ern PAC into West
coast. TX low will shift NEWD across rest of TX (and eventually into
Lwr MS Valley) generating widespread convection. In response,
SE ridge builds NWD. The combination of NRN trough and lifting TX
low will accelerate cold front across TX and lift warm front NWD,
However main forcing will remain well to our west in the vicinity of
cold front. This front will also signal the beginning of a warm and
humid pattern that will last into much of next week. It will also
lift coastal trough NEWD as local winds veer.
Even with all the cloudiness and some sprinkles and drizzle in place
this morning, expect enough breaks in the cloud cover into the aftn
to support temperatures in the low to mid 70s. Latest guidance and
satellite pix suggest cloud/fog erosion from E-W next few hours. So
even though 14z-15z temps running 3-5 degrees below forecast max,
they should rebound some into aftn so won`t make any updates at this
time but monitor closely. So areas in the SE Fl Big Bend could also
get into the mid-upper 70s should more breaks develop in the
overcast. The increasingly warm and moist onshore flow moving over
cooler shelf waters of Gulf will likely continue to generate
sea fog over the marine area and adjacent coast. This is evident in
the local NAM DNG5, other guidance and satellite pix. This
reflected in latest GRIDS.
&&
.SHORT TERM [Tonight Through Friday]...
With the warm front lifting northward through the area by tonight,
the region will be in an increasingly more humid airmass, which
will likely support the formation of fog/stratus after midnight.
Temperatures will also be noticeably warmer with lows around 60
degrees.
Starting Thursday the storm system across Central Texas will
begin to move north northeast around a building mid level ridge
centered over the Florida Peninsula. As this system moves into the
Great Lakes, a weak cold front will move eastward across the
Central Gulf States. The strengthening ridge will slow the
eastward progress of this system as the main upper level energy
continues to move quickly northward. As a result, only low end
rain chances are expected Thursday night into Friday as this front
eventually dissipates across the region.
As was much the case in the near term period, the short term
period will have unseasonably warm temperatures with highs in the
low to mid 70s in the western areas (due to more cloud cover) and
in the upper 70s to near 80 in the east. Overnight lows will be
muggy by January standards, generally in the upper 50s to lower 60s.
&&
.LONG TERM [Friday Night through Tuesday]...
There is good agreement between the GFS and ECMWF that deep layer
ridging will be the dominant synoptic feature over the Southeast.
This correlates to a continuation of above-average temperatures (at
least 10 to 15 degrees warmer than climatology) away from the
beaches (where SSTs remain in the upper 50s to lower 60s). The PoP
will be in the 10 to 30% range- highest along and left of a line
from Albany to Panama City as that region will be closer to the Q-G
forcing and deep layer moisture associated with a persistent
quasi-stationary frontal system.
&&
.AVIATION [through 18z Thursday]...
Updated at 950 am EST-
MVFR cigs will persist across our area (except IFR in fog and light
rain especially at KECP and KVLD until early afternoon. Then, most
cigs will lift to high MVFR, but IFR cigs may persist all day at
KECP. Widespread LIFR (or worse) Vis & cigs are likely tonight,
beginning near the coast shortly after sunset, then spreading inland
later tonight. Our forecast is a blend of the GFS/NAM MOS and latest
HRRR, with emphasis on the HRRR (which has verified well so far this
morning) through this afternoon.
&&
.MARINE...
The pressure gradient will remain tight across the marine area as a
low pressure area lifts northward across Texas and high pressure
persists over the NE gulf. Cautionary level winds will continue
possibly into Thursday before relaxing. Lighter onshore flow is
expected by the weekend as high pressure builds just off the Florida
Peninsula.
&&
.FIRE WEATHER...
Relative humidity levels will remain too moist for red flag
conditions for at least the remainder of this week.
&&
.HYDROLOGY...
No appreciable rainfall amounts are expected through the next few
days.
.PRELIMINARY POINT TEMPS/POPS...
Tallahassee 75 61 77 59 74 / 10 10 10 20 20
Panama City 71 64 74 63 73 / 20 10 10 40 20
Dothan 71 61 75 62 75 / 30 10 10 30 20
Albany 72 60 75 62 75 / 20 10 10 20 20
Valdosta 76 61 78 60 78 / 10 10 10 10 20
Cross City 79 59 79 58 76 / 10 10 10 10 20
Apalachicola 69 64 70 63 70 / 10 10 10 30 20
&&
.TAE WATCHES/WARNINGS/ADVISORIES...
FL...None.
GA...None.
AL...None.
GM...None.
&&
$$
NEAR TERM...Block
SHORT TERM...Godsey
LONG TERM...Fournier
AVIATION...Block
MARINE...Block/Godsey
FIRE WEATHER...Fournier
HYDROLOGY...Godsey
AREA FORECAST DISCUSSION
NWS TALLAHASSEE FL
730 AM EST Wed Jan 9 2013
.UPDATE...
Radar and obs showing sprinkles Wrn third and drizzle Cntrl third of
area. Patchy to areas of fog also seen across much of area including
Ern 2/rd of waters. Updated GRIDS to reflected 12z-15z. Also tweaked
temps/dew points to refelct current scenario.
.NEAR TERM [Through Today]...
03 UTC surface analysis shows a frontal boundary right along the
Northern Gulf Coast. This boundary was well defined, separating a
moist tropical airmass over the Central Gulf from a modified
continental one that has been in place across the Southeast. This
frontal boundary will lift northward today as a strong upper level
system moves through Central Texas. The best forcing for ascent is
expected to remain well off to the west of our region. As a
result, only a slight chance of showers are expected today as the
warm front lifts northward.
This front will also signal the beginning of a warm and humid
pattern that will last into much of next week. Even with all the
cloudiness in place this morning, expect enough breaks in the
cloud cover to support temperatures in the low to mid 70s. Areas
in the Southeast Florida Big Bend could also get into the upper
70s should more breaks develop in the overcast.
&&
.SHORT TERM [Tonight Through Friday]...
With the warm front lifting northward through the area by tonight,
the region will be in an increasingly more humid airmass, which
will likely support the formation of fog/stratus after midnight.
Temperatures will also be noticeably warmer with lows around 60
degrees.
Starting Thursday the storm system across Central Texas will
begin to move north northeast around a building mid level ridge
centered over the Florida Peninsula. As this system moves into the
Great Lakes, a weak cold front will move eastward across the
Central Gulf States. The strengthening ridge will slow the
eastward progress of this system as the main upper level energy
continues to move quickly northward. As a result, only low end
rain chances are expected Thursday night into Friday as this front
eventually dissipates across the region.
As was much the case in the near term period, the short term
period will have unseasonably warm temperatures with highs in the
low to mid 70s in the western areas (due to more cloud cover) and
in the upper 70s to near 80 in the east. Overnight lows will be
muggy by January standards, generally in the upper 50s to lower 60s.
&&
.LONG TERM [Friday Night through Tuesday]...
There is good agreement between the GFS and ECMWF that deep layer
ridging will be the dominant synoptic feature over the Southeast.
This correlates to a continuation of above-average temperatures (at
least 10 to 15 degrees warmer than climatology) away from the
beaches (where SSTs remain in the upper 50s to lower 60s). The PoP
will be in the 10 to 30% range- highest along and left of a line
from Albany to Panama City as that region will be closer to the Q-G
forcing and deep layer moisture associated with a persistent
quasi-stationary frontal system.
&&
.AVIATION [through 12z Thursday]...
Updated at 626 am EST-
KVLD is the only site expected to have IFR Vis this morning.
Otherwise, IFR to low-end MVFR cigs will persist across our area
until early afternoon. Most cigs will lift to MVFR mid to late
afternoon, but IFR cigs may persist all day at KECP. Widespread LIFR
(or worse) Vis & cigs are likely tonight, beginning near the coast
shortly after sunset, then spreading inland later tonight. Our
forecast is a blend of the GFS/NAM MOS and latest HRRR, with
emphasis on the HRRR (which has verified well so far this morning)
through this afternoon.
&&
.MARINE...
The pressure gradient will remain tight across the marine area as
a low pressure area lifts northward across Texas. Cautionary level
winds will continue possibly into Thursday before relaxing. Lighter
onshore flow is expected by the weekend as high pressure builds
just off the Florida Peninsula.
&&
.FIRE WEATHER...
Relative humidity levels will remain too moist for red flag
conditions for at least the remainder of this week.
&&
.HYDROLOGY...
No appreciable rainfall amounts are expected through the next few
days.
&&
.PRELIMINARY POINT TEMPS/POPS...
Tallahassee 75 61 77 59 74 / 10 10 10 20 20
Panama City 71 64 74 63 73 / 20 10 10 40 20
Dothan 71 61 75 62 75 / 20 10 10 30 20
Albany 72 60 75 62 75 / 10 10 10 20 20
Valdosta 76 61 78 60 78 / 10 10 10 10 20
Cross City 79 59 79 58 76 / 10 10 10 10 20
Apalachicola 69 64 70 63 70 / 10 10 10 30 20
&&
.TAE WATCHES/WARNINGS/ADVISORIES...
FL...None.
GA...None.
AL...None.
GM...None.
&&
$$
NEAR TERM...Godsey
SHORT TERM...Godsey
LONG TERM...Fournier
AVIATION...Fournier
MARINE...Godsey
FIRE WEATHER...Fournier
HYDROLOGY...Godsey
AREA FORECAST DISCUSSION
NWS TALLAHASSEE FL
626 AM EST Wed Jan 9 2013
.NEAR TERM [Through Today]...
03 UTC surface analysis shows a frontal boundary right along the
Northern Gulf Coast. This boundary was well defined, separating a
moist tropical airmass over the Central Gulf from a modified
continental one that has been in place across the Southeast. This
frontal boundary will lift northward today as a strong upper level
system moves through Central Texas. The best forcing for ascent is
expected to remain well off to the west of our region. As a
result, only a slight chance of showers are expected today as the
warm front lifts northward.
This front will also signal the beginning of a warm and humid
pattern that will last into much of next week. Even with all the
cloudiness in place this morning, expect enough breaks in the
cloud cover to support temperatures in the low to mid 70s. Areas
in the Southeast Florida Big Bend could also get into the upper
70s should more breaks develop in the overcast.
&&
.SHORT TERM [Tonight Through Friday]...
With the warm front lifting northward through the area by tonight,
the region will be in an increasingly more humid airmass, which
will likely support the formation of fog/stratus after midnight.
Temperatures will also be noticeably warmer with lows around 60
degrees.
Starting Thursday the storm system across Central Texas will
begin to move north northeast around a building mid level ridge
centered over the Florida Peninsula. As this system moves into the
Great Lakes, a weak cold front will move eastward across the
Central Gulf States. The strengthening ridge will slow the
eastward progress of this system as the main upper level energy
continues to move quickly northward. As a result, only low end
rain chances are expected Thursday night into Friday as this front
eventually dissipates across the region.
As was much the case in the near term period, the short term
period will have unseasonably warm temperatures with highs in the
low to mid 70s in the western areas (due to more cloud cover) and
in the upper 70s to near 80 in the east. Overnight lows will be
muggy by January standards, generally in the upper 50s to lower 60s.
&&
.LONG TERM [Friday Night through Tuesday]...
There is good agreement between the GFS and ECMWF that deep layer
ridging will be the dominant synoptic feature over the Southeast.
This correlates to a continuation of above-average temperatures (at
least 10 to 15 degrees warmer than climatology) away from the
beaches (where SSTs remain in the upper 50s to lower 60s). The PoP
will be in the 10 to 30% range- highest along and left of a line
from Albany to Panama City as that region will be closer to the Q-G
forcing and deep layer moisture associated with a persistent
quasi-stationary frontal system.
&&
.AVIATION [through 12z Thursday]...
Updated at 626 am EST-
KVLD is the only site expected to have IFR Vis this morning.
Otherwise, IFR to low-end MVFR cigs will persist across our area
until early afternoon. Most cigs will lift to MVFR mid to late
afternoon, but IFR cigs may persist all day at KECP. Widespread LIFR
(or worse) Vis & cigs are likely tonight, beginning near the coast
shortly after sunset, then spreading inland later tonight. Our
forecast is a blend of the GFS/NAM MOS and latest HRRR, with
emphasis on the HRRR (which has verified well so far this morning)
through this afternoon.
&&
.MARINE...
The pressure gradient will remain tight across the marine area as
a low pressure area lifts northward across Texas. Cautionary level
winds will continue possibly into Thursday before relaxing. Lighter
onshore flow is expected by the weekend as high pressure builds
just off the Florida Peninsula.
&&
.FIRE WEATHER...
Relative humidity levels will remain too moist for red flag
conditions for at least the remainder of this week.
&&
.HYDROLOGY...
No appreciable rainfall amounts are expected through the next few
days.
&&
.PRELIMINARY POINT TEMPS/POPS...
Tallahassee 75 61 77 59 74 / 10 10 10 20 20
Panama City 71 64 74 63 73 / 20 10 10 40 20
Dothan 71 61 75 62 75 / 20 10 10 30 20
Albany 72 60 75 62 75 / 10 10 10 20 20
Valdosta 76 61 78 60 78 / 10 10 10 10 20
Cross City 79 59 79 58 76 / 10 10 10 10 20
Apalachicola 69 64 70 63 70 / 10 10 10 30 20
&&
.TAE WATCHES/WARNINGS/ADVISORIES...
FL...None.
GA...None.
AL...None.
GM...None.
&&
$$
NEAR TERM...Godsey
SHORT TERM...Godsey
LONG TERM...Fournier
AVIATION...Fournier
MARINE...Godsey
FIRE WEATHER...Fournier
HYDROLOGY...Godsey
AREA FORECAST DISCUSSION
NWS TALLAHASSEE FL
242 AM EST Wed Jan 9 2013
.NEAR TERM [Through Today]...
03 UTC surface analysis shows a frontal boundary right along the
Northern Gulf Coast. This boundary was well defined, separating a
moist tropical airmass over the Central Gulf from a modified
continental one that has been in place across the Southeast. This
frontal boundary will lift northward today as a strong upper level
system moves through Central Texas. The best forcing for ascent is
expected to remain well off to the west of our region. As a
result, only a slight chance of showers are expected today as the
warm front lifts northward.
This front will also signal the beginning of a warm and humid
pattern that will last into much of next week. Even with all the
cloudiness in place this morning, expect enough breaks in the
cloud cover to support temperatures in the low to mid 70s. Areas
in the Southeast Florida Big Bend could also get into the upper
70s should more breaks develop in the overcast.
&&
.SHORT TERM [Tonight Through Friday]...
With the warm front lifting northward through the area by tonight,
the region will be in an increasingly more humid airmass, which
will likely support the formation of fog/stratus after midnight.
Temperatures will also be noticeably warmer with lows around 60
degrees.
Starting Thursday the storm system across Central Texas will
begin to move north northeast around a building mid level ridge
centered over the Florida Peninsula. As this system moves into the
Great Lakes, a weak cold front will move eastward across the
Central Gulf States. The strengthening ridge will slow the
eastward progress of this system as the main upper level energy
continues to move quickly northward. As a result, only low end
rain chances are expected Thursday night into Friday as this front
eventually dissipates across the region.
As was much the case in the near term period, the short term
period will have unseasonably warm temperatures with highs in the
low to mid 70s in the western areas (due to more cloud cover) and
in the upper 70s to near 80 in the east. Overnight lows will be
muggy by January standards, generally in the upper 50s to lower 60s.
&&
.LONG TERM [Friday Night through Tuesday]...
There is good agreement between the GFS and ECMWF that deep layer
ridging will be the dominant synoptic feature over the Southeast.
This correlates to a continuation of above-average temperatures (at
least 10 to 15 degrees warmer than climatology) away from the
beaches (where SSTs remain in the upper 50s to lower 60s). The PoP
will be in the 10 to 30% range- highest along and left of a line
from Albany to Panama City as that region will be closer to the Q-G
forcing and deep layer moisture associated with a persistent
quasi-stationary frontal system.
&&
.AVIATION [through 06z Thursday]...
As of 07 UTC there was no fog at the terminals and cigs were low-end
MVFR to IFR. Our local WRF and the latest HRRR fog/cig NWP output
seem to be verifying best so far, and suggest that this will mainly
be a low cig event (except at KVLD where a period of 1/2SM Vis is
likely by dawn). Elsewhere, widespread LIFR-IFR cigs will likely
remain until late morning or early afternoon. MVFR cigs are expected
this afternoon, followed by a return to LIFR-IFR cigs by evening.
Fog may develop sooner and be more widespread Wednesday night.
&&
.MARINE...
The pressure gradient will remain tight across the marine area as
a low pressure area lifts northward across Texas. Cautionary level
winds will continue possibly into Thursday before relaxing. Lighter
onshore flow is expected by the weekend as high pressure builds
just off the Florida Peninsula.
&&
.FIRE WEATHER...
Relative humidity levels will remain too moist for red flag
conditions for at least the remainder of this week.
&&
.HYDROLOGY...
No appreciable rainfall amounts are expected through the next few
days.
&&
.PRELIMINARY POINT TEMPS/POPS...
Tallahassee 75 61 77 59 74 / 10 10 10 20 20
Panama City 71 64 74 63 73 / 20 10 10 40 20
Dothan 71 61 75 62 75 / 20 10 10 30 20
Albany 72 60 75 62 75 / 10 10 10 20 20
Valdosta 76 61 78 60 78 / 10 10 10 10 20
Cross City 79 59 79 58 76 / 10 10 10 10 20
Apalachicola 69 64 70 63 70 / 10 10 10 30 20
&&
.TAE WATCHES/WARNINGS/ADVISORIES...
FL...None.
GA...None.
AL...None.
GM...None.
&&
$$
NEAR TERM...Godsey
SHORT TERM...Godsey
LONG TERM...Fournier
AVIATION...Fournier
MARINE...Godsey
FIRE WEATHER...Fournier
HYDROLOGY...Godsey
AREA FORECAST DISCUSSION
NWS COLUMBIA SC
926 PM EST THU JAN 10 2013
.SYNOPSIS...
A WEAK WARM FRONT WILL SLOWLY SHIFT NORTH TONIGHT AND BE JUST NORTH
OF THE FORECAST AREA FRIDAY. THE HIGHEST CHANCES FOR RAIN WILL BE
TONIGHT INTO FRIDAY WITH THE WARM FRONT. TEMPERATURES THIS WEEKEND
INTO EARLY NEXT WEEK WILL BE WELL ABOVE NORMAL AS AN UPPER RIDGE
BUILDS OVER THE AREA.
&&
.NEAR TERM /UNTIL 6 AM FRIDAY MORNING/...
ONGOING FORECAST GENERALLY CONTINUES TO LOOK ON TRACK...BUT
REFINED DETAIL IN POPS OVERNIGHT TO REFLECT MOVEMENT OF MAIN BATCH
OF LIGHT RAIN ASSOCIATED WITH WEAK WARM FRONT.
UPPER RIDGE CURRENTLY STRETCHING FROM THE CARIBBEAN NORTH ACROSS
THE CAROLINAS AND INTO EASTERN CANADA. WEAK WARM FRONT APPEARS TO
BE GENERALLY STRETCHED ACROSS OUR FORECAST AREA (FA). MODELS
INDICATE A WEAK UPPER IMPULSE WILL MOVE FROM THE GULF COAST NE
ACROSS THE CAROLINAS LATE TONIGHT...WHILE THE WARM FRONT MOVES
NORTH INTO OUR NORTHERN FA. COMBINATION OF FRONT...LOW LEVEL
ISENTROPIC LIFT AND SOME UPPER LIFT TO PROVIDE SOME LIGHT RAIN
POTENTIAL MAINLY NEAR AND NORTH OF THE BOUNDARY. CURRENT RADAR
INDICATES A BAND OF LIGHT RAIN CURRENTLY STRETCHING ACROSS OUR
CENTRAL FA. POPULATED NEAR TERM HOURLY POP GRIDS WITH THE LATEST
HIGH RESOLUTION RUC MODEL...GENERALLY INDICATING MAIN BAND OF
LIGHT RAIN TO CONTINUE MOVING NORTH OVERNIGHT. IN ADDITION TO THE
CURRENT VEIL OF MID AND UPPER LEVEL CLOUDINESS ACROSS THE
REGION...MODELS SUGGEST LOW LEVEL CLOUDINESS/STRATUS DEVELOPING
LATE.
&&
.SHORT TERM /6 AM FRIDAY MORNING THROUGH SATURDAY NIGHT/...
FRIDAY AND FRIDAY NIGHT...WEAK FRONTAL BOUNDARY WILL CONTINUE TO
MOVE TOWARD THE FORECAST AREA WITH ISENTROPIC ASCENT INCREASING
FRIDAY MORNING. WITH MAIN MOISTURE AXIS REMAINING WEST OF THE
FORECAST AREA HAVE CONTINUED WITH HIGHEST POPS OVER THE WESTERN
MIDLANDS AND LOWEST EASTERN MIDLANDS. WITH THE UPPER RIDGE
BUILDING OVER THE EASTERN US TEMPERATURES WILL BE WELL ABOVE
NORMAL WITH HIGHS IN THE MID 60S TO MID 70S AND OVERNIGHT LOWS IN
THE MID 50S FOR MOST LOCATIONS.
SATURDAY AND SATURDAY NIGHT...WEAK BOUNDARY WILL CONTINUE TO SHEAR
APART ACROSS THE REGION WITH ANOTHER AREA OF LOW PRESSURE
DEVELOPING OVER EASTERN TX. MAIN MOISTURE AXIS WILL AGAIN BE WEST
OF THE FORECAST AREA WITH MODEL SOUNDINGS INDICATING DRY AIR IN
THE MID LEVELS. AS SUCH HAVE LOWERED POPS FOR THE AREA RESULTING
IN NO MENTION OF RAIN. TEMPERATURES WILL CONTINUE ABOVE NORMAL
WITH THE UPPER RIDGE...DAYTIME HIGHS IN THE MID TO UPPER 70S AND
OVERNIGHT LOWS IN THE MID 50S.
&&
.LONG TERM /SUNDAY THROUGH THURSDAY/...
FEW CHANGES MADE TO THE LONG TERM FORECAST AS MODELS REMAIN IN
GOOD AGREEMENT. UPPER LEVEL PATTERN REMAINS HIGHLY AMPLIFIED WITH
THE UPPER RIDGE ALONG THE EAST COAST WITH A FRONTAL BOUNDARY
DRAPED OVER THE EASTERN US. WITH THE HIGHLY AMPLIFIED PATTERN THE
FRONT WILL BE SLOW TO PROGRESS EASTWARD WITH PARTLY TO MOSTLY
CLOUDY SKIES PERSISTING OVER THE REGION. BEST CHANCES OF RAIN WILL
BE TUESDAY AND WEDNESDAY...WITH CONFIDENCE LOWERING LATE IN THE
LONG TERM AS MODEL CONSISTENCY DIMINISHES. TEMPERATURES WILL
REMAIN WELL ABOVE NORMAL...WITH A COOLING TREND AS THE RIDGE
BEGINS TO BREAK DOWN ON WEDNESDAY. HAVE TRENDED MOST OF THE LONG
TERM TOWARD THE ECMWF DUE TO RUN TO RUN CONSISTENCY.
&&
.AVIATION /02Z FRIDAY THROUGH TUESDAY/...
HIGH CONFIDENCE FOR IFR/MVFR CONDITIONS THROUGH FRIDAY MORNING.
MVFR CIGS ACCOMPANIED BY LIGHT RAIN SPREADING OVER THE TAF SITES
THIS EVENING GIVING WAY TO IFR CIGS THROUGH 06Z. PATCHES OF LIGHT
RAIN AND DRIZZLE POSSIBLE INTO FRIDAY MORNING. IFR CONDITIONS DURING
THE MORNING IMPROVING TO VFR IN THE AFTERNOON AS THE LOW LEVEL FLOW
BECOMES SOUTH.
EASTERLY WINDS LESS THAN 10 KTS OVERNIGHT BECOMING SOUTH AROUND 10
KTS BY EARLY AFTERNOON.
EXTENDED AVIATION OUTLOOK...THERE WILL LIKELY BE SUFFICIENT
LOW-LEVEL MOISTURE FOR WIDESPREAD MVFR OR IFR CIGS/VSBYS DURING THE
EARLY MORNING HOURS SATURDAY THROUGH MONDAY.
&&
.CAE WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
GA...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS QUAD CITIES IA IL
544 PM CST THU JAN 10 2013
.AVIATION...
IFR AND LIFR CONDITIONS TO PREVAIL ALL TERMINALS THROUGH AT LEAST
11/12Z. WARM MOIST AIR WITH AREAS OF LIGHT TO MODERATE RAIN AND
DRIZZLE WITH FOG WILL MOVE NORTH ACROSS THE REGION AHEAD OF A
SHORT WAVE THAT WILL PASS LATE TONIGHT. EXTENDED PERIODS OF CIGS
AOB 500 FT AND VISIBILITY AOB 1 MILE WITH RAIN/DRIZZLE AND FOG CAN
BE EXPECTED. CID AND DBQ TERMINALS MAY EXPERIENCE PERIODS BELOW
AIRPORT MINIMUMS AFTER 06Z...LASTING INTO THE MID MORNING HOURS.
SOUTHEAST WINDS OF 5 TO 15 KTS WILL SHIFT TO THE SOUTH AND
SOUTHWEST FRIDAY. THE BRL AND MLI TERMINALS WILL IMPROVE TO
PROBABLY VFR CONDITIONS BY FRIDAY AFTERNOON AS THE DISTURBANCE
MOVES NORTHEAST AND MVFR PROBABLE AT CID/DBQ TERMINALS.
NICHOLS
&&
.PREV DISCUSSION... /ISSUED 319 PM CST THU JAN 10 2013/
SYNOPSIS...
12Z UA ANALYSIS HAS THE CUT OFF LOW IN WEST TEXAS WITH A 850MB
WARM FRONT RUNNING FROM CENTRAL OKLAHOMA INTO SOUTHEAST KANSAS. A
VERY SHARP 850MB MOISTURE GRADIENT RAN FROM NORTHWEST MISSOURI
INTO THE OHIO VALLEY. RADAR TRENDS THROUGH THE MORNING AND
AFTERNOON SHOW PLENTY OF VIRGA FROM NORTHERN IOWA INTO NORTHERN
ILLINOIS WITH SFC RAIN FROM SOUTHERN IOWA INTO CENTRAL ILLINOIS.
18Z SFC ANALYSIS HAS THE LOW IN SOUTHWEST OKLAHOMA WITH A
DEVELOPING BOUNDARY FROM CENTRAL OKLAHOMA TO NEAR KMEM. DEW POINTS
WERE IN THE 20S ACROSS THE GREAT LAKES WITH 30S AND 40S FROM THE
CENTRAL PLAINS INTO THE OHIO VALLEY. DEW POINTS IN THE 50S WERE IN
THE LOWER MISSISSIPPI VALLEY.
SHORT TERM...LATE THIS AFTERNOON AND TONIGHT
THE MOISTURE SURGE COMING UP FROM THE SOUTH IS STARTING TO WIN
OVER THE DRY AIR. SPOTTY RAIN OR DRIZZLE IS NOW OVER ROUGHLY THE
SOUTHERN HALF OF THE CWFA WITH SPRINKLES OR VERY SPOTTY RAIN
DEVELOPING OVER THE NORTHERN HALF.
RAP TRENDS INDICATE THAT A VERY RAPID TOP DOWN SATURATION WILL
OCCUR LATE THIS AFTERNOON. SO BY THE EVENING COMMUTE THERE SHOULD
BE FAIRLY WIDESPREAD VERY LIGHT RAIN OR DRIZZLE OCCURRING ACROSS
THE AREA.
TEMPERATURES WILL SLOWLY CLIMB LATE THIS AFTERNOON AS MOISTURE
CONTINUES TO SURGE INTO THE AREA. HIGH TEMPERATURES FOR THE
VERIFYING PERIOD WILL LIKELY OCCUR IN THE 6-8 PM TIME FRAME.
LIKEWISE...OVERNIGHT LOWS WILL LIKELY OCCUR IN THE 7-8 PM TIME
FRAME FOLLOWED BY STEADY OR SLOWLY RISING TEMPERATURES.
TONIGHT...STRONG FORCING MOVES ACROSS THE AREA DURING THE EVENING
WITH A FULLY SATURATED ATMOSPHERE. THE HEAVY RAIN TOOL SUGGESTS
THE EVENING HOURS WILL LIKELY ACCOUNT FOR MUCH OF THE RAINFALL
FROM THIS EVENT. AFTER MIDNIGHT...WIDESPREAD DRIZZLE WILL BE SEEN
BUT ANOTHER ROUND OF FORCING WILL LIKELY ALLOW SOME ADDITIONAL
RAIN TO OCCUR.
ANOTHER CONCERN TONIGHT IS FOG. THERE IS STILL A RESPECTABLE SNOW
FIELD OVER ROUGHLY THE NORTHERN THIRD OF THE CWFA. ADVECTING
MOISTURE INTO THE AREA ALONG WITH RAIN SHOULD ALLOW PATCHY OR SOME
AREAS OF FOG TO DEVELOP LATE THIS EVENING AS WINDS DIMINISH. AFTER
MIDNIGHT WINDS DROP OFF ACROSS THE NORTHWEST THIRD TO 40 PERCENT
OF THE CWFA WITH THE PASSAGE OF THE SFC LOW. AT THIS TIME THE RISK
FOR DENSE FOG WILL BE THE GREATEST.
THEREFORE...WILL ISSUE A DENSE FOG ADVISORY FOR THE MAIN SNOW
FIELD AND WHERE WINDS ARE PROGGED TO BE LIGHT. IT IS HIGHLY LIKELY
THAT THE DENSE FOG ADVISORY MAY HAVE TO BE EXPANDED DURING THE
EVENING OR OVERNIGHT HOURS. ..08..
LONG TERM...FRIDAY THROUGH NEXT WEDNESDAY...
HIGH TEMPERATURES FOR FRIDAY ARE A LARGE QUESTION MARK THIS
FORECAST. THE MAIN COMPLICATING FACTOR IS IN HOW QUICKLY THE LOW
CLOUDS CLEAR FROM SOUTH TO NORTH WITH THE ASSOCIATED CLEARING OF THE
FOG AND DRIZZLE. MODELS HAVE BEEN STRUGGLING WITH THIS ISSUE...WITH
MANY OF THEM KEEPING A TRAPPED LOWER LAYER OF LOW CLOUDS AND FOG
WITH A STRONG ELEVATED MIXED LAYER OVER THE TOP OF IT.
HOWEVER...THEY ALSO DEPICT STRONG SURFACE WINDS...WHICH DOES NOT
MATCH WELL WITH A TRAPPED LOW LEVEL INVERSION. A LOOK AT THE MODEL
INITIALIZATION SHOWS THAT NAM12 MODEL SNOW DEPTH INITIALIZATION IS
FAR TOO FAR SOUTH...WITH 1 INCH OR MORE OF SNOW DEPTH INTO NORTHERN
MISSOURI. GEM AND RUC ARE CLOSER TO REALITY. GFS MODEL SNOW DEPTH
INITIALIZATION MAY NOT BE ANY BETTER THAN THE NAM12...BUT CANNOT
CHECK ON THAT AT THIS TIME. THUS...HAVE DECIDED TO DEFINITELY ALLOW
THE CLOUDS TO CLEAR OUT OF THE SNOW FREE AREAS ACROSS THE SOUTHERN
HALF TO TWO THIRDS OF THE FORECAST AREA...ALLOWING HIGH TEMPS TO GET
INTO THE MID TO UPPER 50S IN THE AFTERNOON. HOWEVER THE NORTH IS A
WHOLE SEPARATE CAN OF WORMS...WITH THE LOW CLOUDS FOG AND DRIZZLE
HANGING ON INTO THE AFTERNOON AND KEEPING TEMPERATURES IN THE 40S TO
NEAR 50 FOR THE MOST PART. THIS MAKES A LARGE RANGE ACROSS THE
FORECAST AREA IN MAX TEMPS...AND STILL LEAVES US WITH A LARGE BUST
POTENTIAL FOR THIS FORECAST. WITH THIS EXTRAORDINARY WARMTH...THE
RECORD HIGH TEMPERATURE FOR BURLINGTON IS AT RISK...AND WE WILL BE
CLOSE AT OTHER LOCATIONS. FOR REFERENCE...HAVE INCLUDED RECORD HIGHS FOR
FRIDAY BELOW.
OF COURSE...THIS IS NOT THE ONLY CONCERN THIS FORECAST. FRIDAY
NIGHT WILL BE MILD WITH TEMPERATURES REMAINING UP. IN
FACT...LOCATIONS ACROSS THE NORTH THAT DO NOT GET INTO THE SUNSHINE
WILL SLOWLY RISE INTO THE EVENING HOURS AND WILL REACH THEIR HIGH
TEMPERATURES IN THE LATE EVENING TO AROUND MIDNIGHT. THE STRONG
COLD FRONT COMES THROUGH EARLY SATURDAY MORNING AND TEMPERATURES
BEGIN TO FALL...WITH ONLY MINIMAL DIURNAL RISE IN THE AFTERNOON.
SATURDAY NIGHT AND SUNDAY THERE IS A WEAK SHORTWAVE THAT MOVES ALONG
A BAROCLINIC ZONE DRAPED FROM TEXAS UP THE OHIO RIVER VALLEY..WHICH
SHOULD PRODUCE A NICE BAND OF SNOW FOR AREAS NORTHWEST OF THE LOW
TRACK. THE TRICK IS WHETHER THIS SYSTEM WILL SHIFT FAR ENOUGH
NORTHWEST TO BRING SOME ACCUMULATING SNOWS TO THE FORECAST AREA
SATURDAY NIGHT AND EARLY SUNDAY. FOR NOW IT APPEARS THAT THE
SOUTHEAST PORTIONS OF THE AREA WILL GET SOME LIGHT SNOW
ACCUMULATIONS...BUT THE NORTHWEST EDGE OF THIS SNOW BAND WILL BE
FAIRLY SHARP...AND THE QUAD CITIES IS PROBABLY ONLY LOOKING SOME
PRETTY MINOR ACCUMULATIONS...DUSTING TO A HALF INCH PERHAPS.
BEHIND THIS SYSTEM WE ARE LOOKING AT GETTING SOME VERY COLD
TEMPERATURES INTO THE AREA...WITH 850MB TEMPS DROPPING TO AROUND
-10C BY MONDAY MORNING. AS LONG AS WE CLEAR OFF...TEMPERATURES WILL
DROP INTO THE TEENS. TEMPERATURES SHOULD SLOWLY MODERATE INTO
WEDNESDAY. ANOTHER LONGWAVE TROUGH IS EXPECTED TO MOVE THROUGH THE
AREA WEDNESDAY...BUT IT IS TOO DRY TO BRING MORE THAN A FRESH SHOT
OF COLDER AIR FOR THURSDAY.
LE
CLIMATE...
CORRECTED THESE RECORD HIGHS.
RECORD HIGHS FOR JANUARY 11...
MOLINE.........56 IN 2012
CEDAR RAPIDS...53 IN 2012
DUBUQUE........52 IN 2012
BURLINGTON.....55 IN 2012
&&
.DVN WATCHES/WARNINGS/ADVISORIES...
IA...DENSE FOG ADVISORY FROM 2 AM TO 10 AM CST FRIDAY FOR BENTON-
BUCHANAN-DELAWARE-DUBUQUE-IOWA-JACKSON-JOHNSON-JONES-LINN.
IL...DENSE FOG ADVISORY FROM 2 AM TO 10 AM CST FRIDAY FOR CARROLL-JO
DAVIESS-STEPHENSON.
MO...NONE.
&&
$$
NICHOLS
AREA FORECAST DISCUSSION...UPDATED
NWS MARQUETTE MI
1100 PM EST THU JAN 10 2013
.UPDATE...
ISSUED AT 1058 PM EST THU JAN 10 2013
WAS VERY CLOSE TO ISSUING A FREEZING RAIN ADVISORY FOR MUCH OF
WESTERN UPPER MICHIGAN BASED ON REPORTS IN EASTERN MN AND PORTIONS
OF WESTERN WISCONSIN. APPEARS THAT EVEN THOUGH TEMPERATURES ARE
SEVERAL DEGREES ABOVE FREEZING...THE BELOW FREEZING SURFACE TEMPS
ARE ENOUGH TO CAUSE ICING ON SOME ROADWAYS IN THOSE AREAS. WITH
MIDOT SITES SHOWING ROAD SURFACE TEMPS AROUND 28 IN IRON COUNTY AND
SEVERAL REPORTS OF LIGHT ICING IN IRON MOUNTAIN AND IRON
RIVER...FEEL THAT THE CURRENT ADVISORY IS IN GOOD SHAPE. TEMPS ARE
FINALLY STARTING TO FALL IN IRONWOOD...DOWN TO 36...BUT WITH MIDOT
ROAD SFC TEMPS IN TWIN LAKES AROUND 32...THOUGHT IT WOULD BE A
LITTLE MORE PATCHY THERE AND FOCUSED OVER FAR EASTERN GOGEBIC
COUNTY. LATEST OBSERVER REPORT INDICATED THAT MAIN
ROADS WERE WET BUT SECONDARY SNOW COVERED ROAD WAS
SLICK. BARAGA/MARQUETTE COUNTIES ARE A CONCERN...BUT WITH THE PRECIP
STARTING AROUND MIDNIGHT...THOUGHT THAT THE COUPLE HOURS OF LIGHT
ICING WOULD HAVE LIMITED IMPACT. THUS...WILL KEEP THE SPS GOING FOR
FOR LOCATIONS OUTSIDE THE ADVISORY.
INITIAL WAVE OF PRECIPITATION SHOULD BE DIMINISHING FROM SOUTH TO
NORTH OVER THE WESTERN THIRD OF THE CWA OVER THE NEXT COUPLE OF
HOURS AND THEN WILL LIKELY SEE FOG/DRIZZLE FOR THE REST OF THE
NIGHT. OVER THE CENTRAL AND EASTERN CWA...SECOND WAVE OF
PRECIPITATION CURRENTLY EXITING NORTHERN ILLINOIS WILL BRING ANOTHER
PERIOD OF RAIN TOWARDS 08-13Z. SURFACE TEMPS WILL BE SLIGHTLY WARMER
AT THAT TIME...BUT STILL COULD SEE SOME ISSUES ON SECONDARY OR SNOW
COVERED ROADS.
PREVIOUS UPDATE
ISSUED AT 835 PM EST THU JAN 10 2013
FORECAST UPDATE MAINLY FOR POTENTIAL FREEZING RAIN THIS EVENING AND
TONIGHT. ONLY MADE MINOR TWEAKS TO THE GOING POPS TO FINE TUNE THE
SHARP START TO THE RAIN. WITH THE STRONG WARM AIR ADVECTION CREATING
A LARGE WARM LAYER ALOFT BASED ON RUC SOUNDINGS...THE PRECIPITATION
WILL FALL AS RAIN. THE QUESTION BECOMES WHAT WHILL HAPPEN ONCE IT
REACHES THE SURFACE. LOOKING AT MIDOT ROAD SENSORS ACROSS THE
CENTRAL CWA...SURFACE TEMPERATURES ARE AROUND 29-30 DEGREES.
THUS...THINKING THAT EVEN IF NEAR SURFACE TEMPERATURES ARE AT OR
JUST ABOVE FREEZING...THERE WILL STILL BE SOME FREEZING ON THE
LESSER TRAVELED ROADWAYS. THEREFORE...OPTED TO ISSUE A FREEZING RAIN
ADVISORY FOR IRON/DICKINSON COUNTIES AT THIS TIME DUE TO HAVING THE
HIGHEST CONFIDENCE FOR OCCURENCE. WAS ON THE EDGE FOR
BARAGA/MARQUETTE COUNTIES FOR THE HIGHER TERRAIN LOCATIONS THAT ARE
ALREADY HOVERING NEAR FREEZING. THE OTHER AREAS SHOULD ONLY SEE VERY
ISOLATED AREAS AND ISSUED AN SPS FOR THEM. HIGH RESOLUTION MODELS
SHOWING DOWNSLOPE WARMING HELPING OVER THE FAR WEST AND OFF LAKE
MICHIGAN OVER THE EAST. IN ADDITION...WITH TEMPS OUT WEST STILL
AROUND 40...DIDN/T FEEL COMFORTABLE ISSUING ONE FOR
GOGEBIC/ONTONAGON. EVEN THOUGH THOSE AREAS ARE WARMER...COLD GROUND
TEMPS COULD STILL PRODUCE SOME SLICK SPOTS.
&&
.SHORT TERM...(THIS EVENING THROUGH FRIDAY)
ISSUED AT 417 PM EST THU JAN 10 2013
TONIGHT...LATEST WATER VAPOR LOOP SHOWS WELL-DEFINED SHORTWAVE OVER
SRN OKLAHOMA. MODELS IN GOOD AGREEMENT ON TRACK OF THIS SHORTWAVE
WHICH IS FCST TO MOVE UP THE MS VALLEY LATER TONIGHT AND THEN INTO
THE LOWER GREAT LAKES ON FRIDAY. MODEL SNDGS CONSISTENT IN SHOWING
DEEP MOISTURE ARRIVING NOT UNTIL LATE THIS EVENING/OVERNIGHT...WITH
MOST PRECIPITATION HOLDING OFF ACROSS THE SOUTHERN CWA UNTIL AFT
03Z. COULD SEE SOME COOLING TO BELOW FREEZING TEMPS ACROSS INTERIOR
LOCATIONS OF THE CWA BEFORE CLOUDS THICKEN WITH THE ARRIVAL OF DEEP
MOISTURE...ESPECIALLY OVER THE WEST HALF WHERE DEWPOINTS ARE STILL
IN THE LOW TEENS AT MANY LOCATIONS. INITIALLY LOWER SFC WET-BULB
TEMPS DUE TO THIS DRIER AIRMASS COULD RESULT IN SOME LIGHT FREEZING
RAIN AT ONSET OF PCPN...BUT AS IN LINE WITH PREV FCST
THINKING...STILL EXPECT TEMPS TO WARM BACK TO IF NOT ABOVE FREEZING
SHORTLY AFTER ONSET OF PRECIPITATION. WITH SSE WINDS PUMPING IN
WARMER AND MORE MOIST AIR THROUGH THE OVERNIGHT HRS...BELIEVE ANY
FREEZING RAIN WILL BE SHORT-LIVED AND PCPN WILL EVENTUALLY TURN OVER
TO ALL RAIN LATER TONIGHT. SO FREEZING RAIN ADVISORY SHOULD NOT BE
NEEDED...BUT PERHAPS AN SPECIAL WEATHER STATEMENT MAY BE NEEDED FOR
EXPECTED SHORT DURATION EVENT.
MODELS STILL SEEM TO INDICATE THE BULK OF THE PRECIP WILL REMAIN
SOUTHEAST OF THE CWA...BUT BRIEF MODERATE RAINFALL COULD AFFECT THE
EAST HALF OF THE CWA AS A RESULT OF STRONG ISENTROPIC LIFT ALONG THE
295-305K SURFACES ON THE NOSE OF A 45-50 KT LLJ AS PRECIPITABLE
WATER VALUES SURPASS ONE INCH (450 PERCENT NORMAL) ACROSS THE EAST
HALF. HAVE SPREAD CATEGORICAL POPS ACROSS THE CWA FROM LATE EVENING
INTO EARLY OVERNIGHT HRS.
FRIDAY...SHORTWAVE PASSES WELL SOUTHEAST ALLOWING WEAK RDGG AND
Q-VECT DIV TO SPREAD IN FROM THE WEST....RESULTING IN DIMINISHING
RAIN CHCS FROM WEST TO EAST DURING THE DAY. DESPITE LINGERING LOW
CLOUDS...EXPECT MAX TEMPS FRI TO BE WELL ABOVE NORMAL GIVEN
UNSEASONABLE WARMTH TONIGHT AND CONTINUED LOW-LEVEL SSW FLOW AHEAD
OF WRN TROF THRU FRI.
.LONG TERM...(FRIDAY NIGHT THROUGH THURSDAY)
ISSUED AT 417 PM EST THU JAN 10 2013
FRI NIGHT...AS SHRTWV LIFTS NEWD OUT OF MEAN TROF OVER THE W HALF OF
NAMERICA...A SFC LO IS PROGGED TO MOVE FM THE PLAINS TO NE MN BY 12Z
SAT. THE FASTER 12Z NAM/CNDN MODELS SHOW ATTENDANT SFC COLD FNT
SWINGING THRU THE FAR W ARND IWD BY 12Z...BUT BULK OF OTHER GUIDANCE
INDICATES A SLOWER FROPA. MODELS INDICATE DRY SLOT UNDER THE JET
SURGE REGION ON THE ERN FLANK OF THE SHRTWV WL DOMINATE THRU THE
NGT...SO EXPECT GENERALLY DRY WX TO PREVAIL WITH ACCOMPANYING
DPVA/LARGER SCALE QVECTOR CNVGC/DEEPER MSTR ASSOCIATED WITH SHRTWV
IMPACTING MAINLY AREAS TO THE W OF UPR MI ON THE CYC SIDE OF THE
TRACK OF THIS DISTURBANCE. RETAINED SOME LO CHC POPS OVER THE LAND
CWA FOR THE POTENTIAL OF MAINLY SOME -DZ. WITH A STEADY S WIND AND
LINGERING LO CLD...EXPECT MIN TEMPS TO RUN WELL ABV NORMAL AGAIN...
EVEN IF SOME COLDER AIR ARRIVES OVER THE FAR W LATE BEHIND A FROPA.
THERE WL BE AREAS OF FOG AWAY FM THE DOWNSLOPE AREAS NEAR LK SUP
WITH MOIST LLVLS/MELTING SN.
SAT...AS SHRTWV/SFC LOW IN NE MN AT 12Z MOVES ENE THRU NRN
ONTARIO...SHARP COLD FRONT WILL CROSS UPPER MI. HOWEVER...SINCE
STRONGEST DEEP LAYER QVECTOR CONVERGENCE ACCOMPANYING DISTURBANCE WL
PASS TO THE N...AXIS OF MIDLVL DRY AIR IS FCST TO LINGER. WITH
ABSENCE OF DYNAMIC FORCING...FROPA SHOULD BE MAINLY DRY. ONLY
EXCEPTION MAY BE OVER THE W...CLOSER TO THE PASSING DYNAMICS/DEEPER
MOISTURE AND WHERE THE LLVL FLOW WILL TAKE ON MORE OF A CYC UPSLOPE
COMPONENT...ESPECIALLY IN THE AFTN. THE ARRIVAL OF H85 TEMPS ARND
-15C TOWARD 00Z SUN WILL ALSO ADD AN INCREASING LES COMPONENT TO THE
MIX. BUT MODELS HAVE TRENDED TOWARD A MORE WSW LLVL FLOW AND HOLDING
THE MORE IMPRESSIVE MOISTENING FARTHER TO THE W... SO LOWERED POPS
EVEN OVER THE FAR W EXCEPT FOR THE KEWEENAW. WITH ARRIVAL OF COLDER
AIR/DECREASING STABILITY...APRCH OF SHARP PRES RISE CENTER WITH
ISALLOBARIC WIND ALIGNED ALONG THE GRADIENT FLOW... AND SHARPENING
PRES GRADIENT ON THE SRN FLANK OF THE LO SHIFTING THRU NRN ONTARIO
THAT PUSHES H925 WINDS UP TO 25-35 KTS...IT WILL BE WINDY. IN
COMBINATION WITH FALLING SFC TEMPS W TO E THRU THE DAY... THE AIR WL
BEGIN TO FEEL MUCH COLDER...ESPECIALLY OVER THE W.
SAT NGT THRU SUN NGT...AS COLDER AIR POURS INTO THE UPR GREAT LKS...
H85 TEMPS ARE PROGGED TO FALL TO -16 TO -18C. PREVIOUS FCST LIKELY
POPS FOR LES LOOK ON TRACK IN AREAS FAVORED BY EXPECTED WNW FLOW
ALONG LK INDUCED TROF FCST TO EXTEND FM THE KEWEENAW INTO THE AREAS
E OF MQT. CONSIDERING THE MORE THAN SUFFICIENT THERMAL
INSTABILITY...DENDRITIC SNOW GROWTH TEMPS FALLING FIRMLY INTO THE
CONVECTIVE LAYER...AND RATHER DEEP MSTR SHOWN BY SOME OF THE
GUIDANCE ALONG THE TROF...MDT SNOW ACCUMS IN THE ADVY CATEGORY WL BE
PSBL IN THE FAVORED SN BELTS.
MON-THU...ALTHOUGH THE PERSISTENT UPR RDG OVER THE SE CONUS THAT
MAINTAINS MORE OF A CONFLUENT FLOW ALF BTWN THE SPLIT NRN/SRN
BRANCHES INTO THE GRT LKS WL LIMIT THE SPREAD OF ARCTIC AIR BOTTLED
UP IN CANADA EARLY IN THE EXTENDED PERIOD...A NUMBER OF THE EXTENDED
MODELS AND THEIR ENSEMBLE MEANS ARE HINTING A NRN BRANCH TROF
CENTERED OVER HUDSON BAY WL DEEPEN BY MID WEEK AS A SERIES OF
SHRTWVS PLUNGE INTO THE NCNTRL CONUS. CONFIDENCE IN THIS SCENARIO IS
INCREASED BY UPR RDG FCST TO BLD OVER GREENLAND WITH BLOCKING AT HI
LATITUDES. IF THIS NEGATIVE NAO PATTERN DOES INDEED DVLP...MUCH
COLDER ARCTIC AIR MAY SURGE INTO THE AREA ON WED/THU. IN FACT...THE
00Z ECWMF IS ADVERTISING H85 TEMPS IN THE -20C TO -25C RANGE BY THU.
AS FOR DAY TO DAY WX...MON/TUE MAY BE RELATIVELY QUIET WITH A WSW
LLVL FLOW ARND SFC HI PRES BRIEFLY ADVECTING SOMEWHAT MILDER AIR AND
LIMITING LES... H85 TEMPS ARND -10C...INTO THE UPR LKS. THE
COMBINATION OF PASSING SHRTWVS/ARRIVAL OF COLDER AIR WL THEN
INCREASE THE POTENTIAL FOR SGNFT LES ON WED/THU. TENDED HIER THAN
MODEL CONSENSUS POPS FOR THIS TIME PERIOD IN THE FAVORED SN BELTS.
OTRW...NO LARGE SCALE PCPN EVENTS APPEAR TO BE ON THE HORIZON.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z FRIDAY EVENING)
ISSUED AT 635 PM EST THU JAN 10 2013
LINGERING DRY AIR WILL PRODUCE VFR CONDITIONS AT THE TAF SITES FOR
THE FIRST COUPLE OF HOURS. BROAD AREA OF RAIN CURRENTLY MOVING
NORTH THROUGH SOUTHERN WISCONSIN WILL BE MOVE ACROSS UPPER MICHIGAN
LATE THIS EVENING AND OVERNIGHT. THIS WILL DROP CEILINGS TO
IFR DURING THE OVERNIGHT HOURS...WITH SOME SITES AT ALTERNATE
LANDING MINIMUMS. BEHIND THE WAVE OF PRECIPITATION...WARM MOIST AIR
WILL LEAD TO LOW CLOUDS THROUGH THE REST OF THE PERIOD AND ALSO
SOME FOG. EXPECT THE FOG TO HAVE THE LOWEST VISIBILITIES AT KSAW
WITH THE FAVORABLE SSE FLOW INITIALLY AND THEN BACKING TO THE SW.
THERE MAY BE SOME SLIGHT LIFT TO THE CEILINGS ABOVE ALTERNATE
LANDING MINS TOMORROW AFTERNOON...BUT THEY WILL LIKELY GO BACK DOWN
AS THE SUN SETS AND FOG REDEVELOPS.
FINALLY...DID ADD A TEMPO FOR KSAW DURING THE FIRST COUPLE OF HOURS
DUE TO FAVORABLE UPSLOPE FLOW FROM THE CLOUDS FROM THE CLOUDS COMING
OFF LAKE MICHIGAN.
&&
.MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 417 PM EST THU JAN 10 2013
A TIGHT PRESSURE GRADIENT BTWN APPROACHING LOW PRESSURE TROUGH FROM
THE NRN PLAINS AND A HIGH PRES RDG OVER THE ERN LAKES WILL RESULT IN
SOUTH TO SOUTHEAST WINDS TO 25 KNOTS ACROSS THE ERN HALF OF LAKE
SUPERIOR TONIGHT INTO FRI MORNING. WINDS SHOULD STAY AT OR BELOW 20
KTS OVER THE WEST HALF. A STRONG TEMPERATURE INVERSION ABOVE THE
SURFACE SHOULD KEEP STRONG WINDS ALOFT FROM MIXING TO THE
SURFACE...BUT A FEW GUSTS OVER 30 KNOTS OVER THE EAST HALF ARE NOT
OUT OF THE QUESTION. WINDS WILL DIMINISH BLO 20 KT FRI AFTERNOON AS
PRES GRADIENT WEAKENS.
WITH WEAK PRES GRADIENT OVER THE LAKE FRI EVNG...EXPECT SSW WINDS
UNDER 20 KTS WINDS. BUT THESE WINDS WILL INCREASE LATER FRI NIGHT
W-E AS A DEEP LO PRES SYSTEM MOVES NE FROM THE PLAINS INTO NE MN AND
SHARPENS THE GRADIENT. LOOK FOR THESE WINDS TO THEN INCREASE RAPIDLY
ON SAT AS THE SHARP COLD FRONT SLICES ACROSS THE UPPER GREAT LAKES
AND THE ARRIVAL OF MUCH COLDER AIR RESULTS IN DECREASING STABILITY/
GREATER MIXING OF THE STRONGER WINDS TO THE LAKE SURFACE. OPTED TO
HOIST GALE WATCH FOR THE W HALF GIVEN TERRAIN ENHANCED WSW FLOW AND
APPROACH OF PRES RISE CENTER THAT WILL SHARPEN THE LARGER SCALE
WINDS. THE COMBINATION OF THE STRONG WINDS/COLDER AIR/HIER WAVES
WILL RESULT IN FREEZING SPRAY AS WELL INTO SAT NIGHT WHEN THE WINDS
WILL BE DIMINISHING WITH DEPARTURE OF LO PRES TO THE NE/WEAKENING
GRADIENT. WINDS ON SUN INTO MON ARE FORECAST IN THE 15 TO 25 KT
RANGE FOR THE MOST PART...BUT THE APPROACH OF ANOTHER DISTURBANCE
LATER ON TUE/TUE NIGHT MIGHT RESULT IN W-SW WINDS INCREASING UP TO
30 KTS AND MORE FREEZING SPRAY.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
FREEZING RAIN ADVISORY UNTIL 6 AM CST FRIDAY FOR MIZ010-011.
LAKE SUPERIOR...
GALE WATCH FROM SATURDAY MORNING THROUGH SATURDAY EVENING FOR
LSZ162-263-264.
LAKE MICHIGAN...
NONE.
&&
$$
UPDATE...SRF
SHORT TERM...VOSS
LONG TERM...KC
AVIATION...SRF
MARINE...VOSS/KC
AREA FORECAST DISCUSSION...UPDATED
NWS MARQUETTE MI
835 PM EST THU JAN 10 2013
.UPDATE...
ISSUED AT 835 PM EST THU JAN 10 2013
FORECAST UPDATE MAINLY FOR POTENTIAL FREEZING RAIN THIS EVENING AND
TONIGHT. ONLY MADE MINOR TWEAKS TO THE GOING POPS TO FINE TUNE THE
SHARP START TO THE RAIN. WITH THE STRONG WARM AIR ADVECTION CREATING
A LARGE WARM LAYER ALOFT BASED ON RUC SOUNDINGS...THE PRECIPITATION
WILL FALL AS RAIN. THE QUESTION BECOMES WHAT WHILL HAPPEN ONCE IT
REACHES THE SURFACE. LOOKING AT MIDOT ROAD SENSORS ACROSS THE
CENTRAL CWA...SURFACE TEMPERATURES ARE AROUND 29-30 DEGREES.
THUS...THINKING THAT EVEN IF NEAR SURFACE TEMPERATURES ARE AT OR
JUST ABOVE FREEZING...THERE WILL STILL BE SOME FREEZING ON THE
LESSER TRAVELED ROADWAYS. THEREFORE...OPTED TO ISSUE A FREEZING RAIN
ADVISORY FOR IRON/DICKINSON COUNTIES AT THIS TIME DUE TO HAVING THE
HIGHEST CONFIDENCE FOR OCCURENCE. WAS ON THE EDGE FOR
BARAGA/MARQUETTE COUNTIES FOR THE HIGHER TERRAIN LOCATIONS THAT ARE
ALREADY HOVERING NEAR FREEZING. THE OTHER AREAS SHOULD ONLY SEE VERY
ISOLATED AREAS AND ISSUED AN SPS FOR THEM. HIGH RESOLUTION MODELS
SHOWING DOWNSLOPE WARMING HELPING OVER THE FAR WEST AND OFF LAKE
MICHIGAN OVER THE EAST. IN ADDITION...WITH TEMPS OUT WEST STILL
AROUND 40...DIDN/T FEEL COMFORTABLE ISSUING ONE FOR
GOGEBIC/ONTONAGON. EVEN THOUGH THOSE AREAS ARE WARMER...COLD GROUND
TEMPS COULD STILL PRODUCE SOME SLICK SPOTS.
&&
.SHORT TERM...(THIS EVENING THROUGH FRIDAY)
ISSUED AT 417 PM EST THU JAN 10 2013
TONIGHT...LATEST WATER VAPOR LOOP SHOWS WELL-DEFINED SHORTWAVE OVER
SRN OKLAHOMA. MODELS IN GOOD AGREEMENT ON TRACK OF THIS SHORTWAVE
WHICH IS FCST TO MOVE UP THE MS VALLEY LATER TONIGHT AND THEN INTO
THE LOWER GREAT LAKES ON FRIDAY. MODEL SNDGS CONSISTENT IN SHOWING
DEEP MOISTURE ARRIVING NOT UNTIL LATE THIS EVENING/OVERNIGHT...WITH
MOST PRECIPITATION HOLDING OFF ACROSS THE SOUTHERN CWA UNTIL AFT
03Z. COULD SEE SOME COOLING TO BELOW FREEZING TEMPS ACROSS INTERIOR
LOCATIONS OF THE CWA BEFORE CLOUDS THICKEN WITH THE ARRIVAL OF DEEP
MOISTURE...ESPECIALLY OVER THE WEST HALF WHERE DEWPOINTS ARE STILL
IN THE LOW TEENS AT MANY LOCATIONS. INITIALLY LOWER SFC WET-BULB
TEMPS DUE TO THIS DRIER AIRMASS COULD RESULT IN SOME LIGHT FREEZING
RAIN AT ONSET OF PCPN...BUT AS IN LINE WITH PREV FCST
THINKING...STILL EXPECT TEMPS TO WARM BACK TO IF NOT ABOVE FREEZING
SHORTLY AFTER ONSET OF PRECIPITATION. WITH SSE WINDS PUMPING IN
WARMER AND MORE MOIST AIR THROUGH THE OVERNIGHT HRS...BELIEVE ANY
FREEZING RAIN WILL BE SHORT-LIVED AND PCPN WILL EVENTUALLY TURN OVER
TO ALL RAIN LATER TONIGHT. SO FREEZING RAIN ADVISORY SHOULD NOT BE
NEEDED...BUT PERHAPS AN SPECIAL WEATHER STATEMENT MAY BE NEEDED FOR
EXPECTED SHORT DURATION EVENT.
MODELS STILL SEEM TO INDICATE THE BULK OF THE PRECIP WILL REMAIN
SOUTHEAST OF THE CWA...BUT BRIEF MODERATE RAINFALL COULD AFFECT THE
EAST HALF OF THE CWA AS A RESULT OF STRONG ISENTROPIC LIFT ALONG THE
295-305K SURFACES ON THE NOSE OF A 45-50 KT LLJ AS PRECIPITABLE
WATER VALUES SURPASS ONE INCH (450 PERCENT NORMAL) ACROSS THE EAST
HALF. HAVE SPREAD CATEGORICAL POPS ACROSS THE CWA FROM LATE EVENING
INTO EARLY OVERNIGHT HRS.
FRIDAY...SHORTWAVE PASSES WELL SOUTHEAST ALLOWING WEAK RDGG AND
Q-VECT DIV TO SPREAD IN FROM THE WEST....RESULTING IN DIMINISHING
RAIN CHCS FROM WEST TO EAST DURING THE DAY. DESPITE LINGERING LOW
CLOUDS...EXPECT MAX TEMPS FRI TO BE WELL ABOVE NORMAL GIVEN
UNSEASONABLE WARMTH TONIGHT AND CONTINUED LOW-LEVEL SSW FLOW AHEAD
OF WRN TROF THRU FRI.
.LONG TERM...(FRIDAY NIGHT THROUGH THURSDAY)
ISSUED AT 417 PM EST THU JAN 10 2013
FRI NIGHT...AS SHRTWV LIFTS NEWD OUT OF MEAN TROF OVER THE W HALF OF
NAMERICA...A SFC LO IS PROGGED TO MOVE FM THE PLAINS TO NE MN BY 12Z
SAT. THE FASTER 12Z NAM/CNDN MODELS SHOW ATTENDANT SFC COLD FNT
SWINGING THRU THE FAR W ARND IWD BY 12Z...BUT BULK OF OTHER GUIDANCE
INDICATES A SLOWER FROPA. MODELS INDICATE DRY SLOT UNDER THE JET
SURGE REGION ON THE ERN FLANK OF THE SHRTWV WL DOMINATE THRU THE
NGT...SO EXPECT GENERALLY DRY WX TO PREVAIL WITH ACCOMPANYING
DPVA/LARGER SCALE QVECTOR CNVGC/DEEPER MSTR ASSOCIATED WITH SHRTWV
IMPACTING MAINLY AREAS TO THE W OF UPR MI ON THE CYC SIDE OF THE
TRACK OF THIS DISTURBANCE. RETAINED SOME LO CHC POPS OVER THE LAND
CWA FOR THE POTENTIAL OF MAINLY SOME -DZ. WITH A STEADY S WIND AND
LINGERING LO CLD...EXPECT MIN TEMPS TO RUN WELL ABV NORMAL AGAIN...
EVEN IF SOME COLDER AIR ARRIVES OVER THE FAR W LATE BEHIND A FROPA.
THERE WL BE AREAS OF FOG AWAY FM THE DOWNSLOPE AREAS NEAR LK SUP
WITH MOIST LLVLS/MELTING SN.
SAT...AS SHRTWV/SFC LOW IN NE MN AT 12Z MOVES ENE THRU NRN
ONTARIO...SHARP COLD FRONT WILL CROSS UPPER MI. HOWEVER...SINCE
STRONGEST DEEP LAYER QVECTOR CONVERGENCE ACCOMPANYING DISTURBANCE WL
PASS TO THE N...AXIS OF MIDLVL DRY AIR IS FCST TO LINGER. WITH
ABSENCE OF DYNAMIC FORCING...FROPA SHOULD BE MAINLY DRY. ONLY
EXCEPTION MAY BE OVER THE W...CLOSER TO THE PASSING DYNAMICS/DEEPER
MOISTURE AND WHERE THE LLVL FLOW WILL TAKE ON MORE OF A CYC UPSLOPE
COMPONENT...ESPECIALLY IN THE AFTN. THE ARRIVAL OF H85 TEMPS ARND
-15C TOWARD 00Z SUN WILL ALSO ADD AN INCREASING LES COMPONENT TO THE
MIX. BUT MODELS HAVE TRENDED TOWARD A MORE WSW LLVL FLOW AND HOLDING
THE MORE IMPRESSIVE MOISTENING FARTHER TO THE W... SO LOWERED POPS
EVEN OVER THE FAR W EXCEPT FOR THE KEWEENAW. WITH ARRIVAL OF COLDER
AIR/DECREASING STABILITY...APRCH OF SHARP PRES RISE CENTER WITH
ISALLOBARIC WIND ALIGNED ALONG THE GRADIENT FLOW... AND SHARPENING
PRES GRADIENT ON THE SRN FLANK OF THE LO SHIFTING THRU NRN ONTARIO
THAT PUSHES H925 WINDS UP TO 25-35 KTS...IT WILL BE WINDY. IN
COMBINATION WITH FALLING SFC TEMPS W TO E THRU THE DAY... THE AIR WL
BEGIN TO FEEL MUCH COLDER...ESPECIALLY OVER THE W.
SAT NGT THRU SUN NGT...AS COLDER AIR POURS INTO THE UPR GREAT LKS...
H85 TEMPS ARE PROGGED TO FALL TO -16 TO -18C. PREVIOUS FCST LIKELY
POPS FOR LES LOOK ON TRACK IN AREAS FAVORED BY EXPECTED WNW FLOW
ALONG LK INDUCED TROF FCST TO EXTEND FM THE KEWEENAW INTO THE AREAS
E OF MQT. CONSIDERING THE MORE THAN SUFFICIENT THERMAL
INSTABILITY...DENDRITIC SNOW GROWTH TEMPS FALLING FIRMLY INTO THE
CONVECTIVE LAYER...AND RATHER DEEP MSTR SHOWN BY SOME OF THE
GUIDANCE ALONG THE TROF...MDT SNOW ACCUMS IN THE ADVY CATEGORY WL BE
PSBL IN THE FAVORED SN BELTS.
MON-THU...ALTHOUGH THE PERSISTENT UPR RDG OVER THE SE CONUS THAT
MAINTAINS MORE OF A CONFLUENT FLOW ALF BTWN THE SPLIT NRN/SRN
BRANCHES INTO THE GRT LKS WL LIMIT THE SPREAD OF ARCTIC AIR BOTTLED
UP IN CANADA EARLY IN THE EXTENDED PERIOD...A NUMBER OF THE EXTENDED
MODELS AND THEIR ENSEMBLE MEANS ARE HINTING A NRN BRANCH TROF
CENTERED OVER HUDSON BAY WL DEEPEN BY MID WEEK AS A SERIES OF
SHRTWVS PLUNGE INTO THE NCNTRL CONUS. CONFIDENCE IN THIS SCENARIO IS
INCREASED BY UPR RDG FCST TO BLD OVER GREENLAND WITH BLOCKING AT HI
LATITUDES. IF THIS NEGATIVE NAO PATTERN DOES INDEED DVLP...MUCH
COLDER ARCTIC AIR MAY SURGE INTO THE AREA ON WED/THU. IN FACT...THE
00Z ECWMF IS ADVERTISING H85 TEMPS IN THE -20C TO -25C RANGE BY THU.
AS FOR DAY TO DAY WX...MON/TUE MAY BE RELATIVELY QUIET WITH A WSW
LLVL FLOW ARND SFC HI PRES BRIEFLY ADVECTING SOMEWHAT MILDER AIR AND
LIMITING LES... H85 TEMPS ARND -10C...INTO THE UPR LKS. THE
COMBINATION OF PASSING SHRTWVS/ARRIVAL OF COLDER AIR WL THEN
INCREASE THE POTENTIAL FOR SGNFT LES ON WED/THU. TENDED HIER THAN
MODEL CONSENSUS POPS FOR THIS TIME PERIOD IN THE FAVORED SN BELTS.
OTRW...NO LARGE SCALE PCPN EVENTS APPEAR TO BE ON THE HORIZON.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z FRIDAY EVENING)
ISSUED AT 635 PM EST THU JAN 10 2013
LINGERING DRY AIR WILL PRODUCE VFR CONDITIONS AT THE TAF SITES FOR
THE FIRST COUPLE OF HOURS. BROAD AREA OF RAIN CURRENTLY MOVING
NORTH THROUGH SOUTHERN WISCONSIN WILL BE MOVE ACROSS UPPER MICHIGAN
LATE THIS EVENING AND OVERNIGHT. THIS WILL DROP CEILINGS TO
IFR DURING THE OVERNIGHT HOURS...WITH SOME SITES AT ALTERNATE
LANDING MINIMUMS. BEHIND THE WAVE OF PRECIPITATION...WARM MOIST AIR
WILL LEAD TO LOW CLOUDS THROUGH THE REST OF THE PERIOD AND ALSO
SOME FOG. EXPECT THE FOG TO HAVE THE LOWEST VISIBILITIES AT KSAW
WITH THE FAVORABLE SSE FLOW INITIALLY AND THEN BACKING TO THE SW.
THERE MAY BE SOME SLIGHT LIFT TO THE CEILINGS ABOVE ALTERNATE
LANDING MINS TOMORROW AFTERNOON...BUT THEY WILL LIKELY GO BACK DOWN
AS THE SUN SETS AND FOG REDEVELOPS.
FINALLY...DID ADD A TEMPO FOR KSAW DURING THE FIRST COUPLE OF HOURS
DUE TO FAVORABLE UPSLOPE FLOW FROM THE CLOUDS FROM THE CLOUDS COMING
OFF LAKE MICHIGAN.
&&
.MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 417 PM EST THU JAN 10 2013
A TIGHT PRESSURE GRADIENT BTWN APPROACHING LOW PRESSURE TROUGH FROM
THE NRN PLAINS AND A HIGH PRES RDG OVER THE ERN LAKES WILL RESULT IN
SOUTH TO SOUTHEAST WINDS TO 25 KNOTS ACROSS THE ERN HALF OF LAKE
SUPERIOR TONIGHT INTO FRI MORNING. WINDS SHOULD STAY AT OR BELOW 20
KTS OVER THE WEST HALF. A STRONG TEMPERATURE INVERSION ABOVE THE
SURFACE SHOULD KEEP STRONG WINDS ALOFT FROM MIXING TO THE
SURFACE...BUT A FEW GUSTS OVER 30 KNOTS OVER THE EAST HALF ARE NOT
OUT OF THE QUESTION. WINDS WILL DIMINISH BLO 20 KT FRI AFTERNOON AS
PRES GRADIENT WEAKENS.
WITH WEAK PRES GRADIENT OVER THE LAKE FRI EVNG...EXPECT SSW WINDS
UNDER 20 KTS WINDS. BUT THESE WINDS WILL INCREASE LATER FRI NIGHT
W-E AS A DEEP LO PRES SYSTEM MOVES NE FROM THE PLAINS INTO NE MN AND
SHARPENS THE GRADIENT. LOOK FOR THESE WINDS TO THEN INCREASE RAPIDLY
ON SAT AS THE SHARP COLD FRONT SLICES ACROSS THE UPPER GREAT LAKES
AND THE ARRIVAL OF MUCH COLDER AIR RESULTS IN DECREASING STABILITY/
GREATER MIXING OF THE STRONGER WINDS TO THE LAKE SURFACE. OPTED TO
HOIST GALE WATCH FOR THE W HALF GIVEN TERRAIN ENHANCED WSW FLOW AND
APPROACH OF PRES RISE CENTER THAT WILL SHARPEN THE LARGER SCALE
WINDS. THE COMBINATION OF THE STRONG WINDS/COLDER AIR/HIER WAVES
WILL RESULT IN FREEZING SPRAY AS WELL INTO SAT NIGHT WHEN THE WINDS
WILL BE DIMINISHING WITH DEPARTURE OF LO PRES TO THE NE/WEAKENING
GRADIENT. WINDS ON SUN INTO MON ARE FORECAST IN THE 15 TO 25 KT
RANGE FOR THE MOST PART...BUT THE APPROACH OF ANOTHER DISTURBANCE
LATER ON TUE/TUE NIGHT MIGHT RESULT IN W-SW WINDS INCREASING UP TO
30 KTS AND MORE FREEZING SPRAY.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
FREEZING RAIN ADVISORY UNTIL 6 AM CST FRIDAY FOR MIZ010-011.
LAKE SUPERIOR...
GALE WATCH FROM SATURDAY MORNING THROUGH SATURDAY EVENING FOR
LSZ162-263-264.
LAKE MICHIGAN...
NONE.
&&
$$
UPDATE...SRF
SHORT TERM...VOSS
LONG TERM...KC
AVIATION...SRF
MARINE...VOSS/KC
AREA FORECAST DISCUSSION
NWS GAYLORD MI
117 PM EST WED JAN 9 2013
.SYNOPSIS...
ISSUED AT 405 AM EST WED JAN 9 2013
A WEAK COLD FRONT CROSSING THE AREA THIS MORNING WILL USHER IN A
BRIEF PERIOD OF WINDY AND COOLER CONDITIONS TODAY...BUT WITH LITTLE
MORE THAN A FEW LIGHT SNOW SHOWERS OR FLURRIES EXPECTED. HIGH
PRESSURE IS THEN SET TO ARRIVE WITH WARMER WEATHER FOR THURSDAY...
BEFORE LOW PRESSURE TRACKS THROUGH THE AREA INTO FRIDAY. THIS SYSTEM
WILL BRING A WIDESPREAD ROUND OF RAIN TO ALL AREAS...WITH
TEMPERATURES SOARING WELL ABOVE NORMAL. THAT WARMTH WILL STICK
AROUND INTO SATURDAY...BEFORE ANOTHER COLD FRONT BRINGS A RETURN TO
COLDER WEATHER SUNDAY AND INTO NEXT WEEK.
&&
.UPDATE...
ISSUED AT 1247 PM EST WED JAN 9 2013
THE COLD POOL FOLLOWING THE FRONT HAS FINALLY ARRIVED WITH THE
TEMPERATURES NEEDED FOR SELF-DESTRUCT SUNSHINE. 850 MB TEMPERATURES
BASED ON THE HRRR ARE NOW CREEPING DOWN TO AROUND -8C WITH THE
WIND FLOW OVER N LAKE MICHIGAN, AND MAINLY A WEST FLOW. SO MAIN
CLOUD AREAS AND LIGHT SNOW/SPRINKLE RETURNS ARE SPREADING SOUTH
AND EAST OVER THE FORECAST AREA. CLOUDS ARE AS FAR SOUTH AS M-55,
WHILE THE FLURRIES ARE ONLY TO AROUND M-72 WITH THE WEST WIND WILL
EXPECT THAT THIS WILL SPREAD TO THE EAST NORTH OF M-72 THE REST OF
THE AFTERNOON. HOWEVER, THE DRY AIR IN THE LOWER PART OF THE
ATMOSPHERE WILL LIMIT ANY MAJOR SNOW IN N LOWER, AND IS PROBABLY THE
REASON THAT WE ARE SNOWING WITH THE SFC TEMPERATURES BETWEEN 35
AND 40F THIS AFTERNOON. WILL HAVE TO SEE IF THE CLOUDS WILL
CONTINUE TO GENERATE OFF OF LAKE MICHIGAN, OR WILL THEY DRY OUT
LIKE OVER IN N WISCONSIN. WITH THE 850 MB TEMPERATURES, WILL SEE
CLOUDS FOR A FEW MORE HOURS, BEFORE THE WARMER AIR MOVES IN THIS
EVENING AND KICKS THE CLOUDS OUT OF HERE.
UPDATE ISSUED AT 1027 AM EST WED JAN 9 2013
TWEAKED THE TEMPERATURES, BOTH HOURLY AND HIGHS FOR TODAY. MAIN
PROBLEM HAS BEEN THAT WHILE WE ARE COLD ADVECTING, THE MIXING AND
SUNSHINE THAT IS BREAKING THROUGH, HAS BEEN ABLE TO OVERCOME THE
COLD ADVECTION. THE COLDER AIR IS PUSHING INTO THE REGION, BUT IT
WILL TAKE UNTIL THIS AFTERNOON BEFORE WE SEE THE TEMPERATURES
BEGIN TO FALL. THERE WAS A BRIEF LINE OF RAIN SHOWERS THAT MOVED
THROUGH E UPPER AND THE TIP OF THE MITT, BUT IT HAS SINCE FALLEN
APART AND MOVED EAST.
UPDATE ISSUED AT 654 AM EST WED JAN 9 2013
MADE SOME ADJUSTMENTS TO SKY COVER FORECAST BASED ON SATELLITE
TRENDS. THINK WE MAY SEE MORE SUN ACROSS CENTRAL LOWER COUNTIES BY
LATER THIS MORNING WITH MORE CLOUDS NORTH...AND HAVE ADJUSTED
FORECAST TO REFLECT THIS.
&&
.SHORT TERM...(TODAY THROUGH TONIGHT)
ISSUED AT 405 AM EST WED JAN 9 2013
THREE MAIN FEATURES IN THE LARGE SCALE FLOW PATTERN EARLY THIS
MORNING...ONE CLOSEST TO HOME IS A SHORT WAVE TROUGH CROSSING THE
UPPER MIDWEST/UPPER GREAT LAKES WITHIN A PROGRESSIVE NORTHERN BRANCH
SPLIT FLOW PATTERN...WITH AN UPPER LOW OVER NORTHERN MEXICO WITHIN
THE SOUTHERN BRANCH. ANOTHER STRONG UPPER WAVE WAS JUST OFF THE
WEST COAST OF NORTH AMERICA. MIDNIGHT SURFACE ANALYSIS SHOWS A COLD
FRONT ASSOCIATED WITH THE UPPER MIDWEST SHORT WAVE TROUGH STRETCHING
FROM A 996MB SURFACE LOW OVER NORTHWEST ONTARIO...SOUTH ACROSS
WESTERN WISCONSIN/EASTERN IOWA. A SECONDARY FRONT WAS TRAILING BACK
ACROSS CENTRAL MANITOBA/NORTH DAKOTA. AHEAD OF THE UPPER LEVEL
WAVE...CLOUDS HAVE OVERSPREAD NORTHERN MICHIGAN. CLOUD TOPS HAVE
BEEN COOLING ACROSS WISCONSIN AHEAD OF THE 700MB TROUGH AXIS WHERE
STRONGEST UPWARD QG RESPONSE WAS OCCURRING ALONG WITH A BIT OF
SLOPED FRONTOGENETIC FORCING...AND GETTING AN INCREASE IN RADAR
RETURNS AS WELL THOUGH SURFACE BASED PRECIPITATION REPORTS HAVE BEEN
HARD TO COME BY GIVEN RELATIVE DRYNESS IN THE 850-650MB LAYER.
THERE IS A NARROW BAND OF SNOW THAT HAS DEVELOPED ACROSS NORTH
CENTRAL LOWER...AND IT IS SNOWING RATHER IMPRESSIVELY OUT THE WINDOW
AS I TYPE.
NORTHERN ONTARIO LOW HAS BEEN TRACKING EAST SINCE THIS AFTERNOON...
WITH A BROAD AREA OF 3-5MB/3H PRESSURE FALLS AHEAD OF IT. LOW IS
EXPECTED TO TRACK TOWARD THE SOUTHERN TIP OF JAMES BAY TODAY...WHICH
IN TURN WILL DRAG THE LEADING COLD FRONT ACROSS NORTHERN MICHIGAN BY
MID TO LATE MORNING. DECENT CYCLONIC PRESSURE GRADIENT ACROSS THE
UPPER LAKES TODAY...GIVING WAY TO SURFACE RIDGING TONIGHT WITH
STRONG HEIGHT RISES ALOFT (570DM 500MB HEIGHTS FORECAST BY THURSDAY
MORNING...2-3 STANDARD DEVIATIONS ABOVE THE MEAN FOR EARLY
JANUARY). MAIN FORECAST ISSUES IN THE NEAR TERM WILL FOCUS ON SHORT
WAVE PASSAGE THIS MORNING...GUSTY WEST WINDS LATER TODAY...AND LAKE
RESPONSE WITH COLD ADVECTION IN THE WAKE OF THIS MORNING`S COLD
FRONTAL PASSAGE.
WHATEVER PRECIPITATION FALLS WITH THE INITIAL PUSH OF UPWARD FORCING
WILL BE QUICK TO DEPART AS 700MB WAVE SWEEPS QUICKLY THROUGH THE
FORECAST AREA (EXTRAPOLATION FROM IR/WATER VAPOR IMAGERY SUGGESTS BY
12Z-13Z). GOOD DEAL OF LOW CLOUDS BEHIND THE FRONT THAT WILL SPREAD
INTO EASTERN UPPER AND NORTHWEST LOWER AROUND OR SHORTLY AFTER
DAYBREAK. NARROW 925MB THERMAL TROUGH FORECAST TO CROSS NORTHERN
LAKE MICHIGAN BEHIND THE FRONT...WITH TEMPERATURES OF -3 TO -4C
ENOUGH TO SUPPORT A SHALLOW LAKE RESPONSE. FORECAST SOUNDINGS SHOW
A SATURATED MIXED LAYER BELOW 875MB...AND AT TEMPERATURES MOSTLY
ABOVE -7C. IR CLOUD TOP TEMPERATURES ACROSS NORTHWEST WISCONSIN
AROUND -9 TO -11C...WITH CEILINGS IN THE VICINITY OF 1500 FEET. SO
DEFINITELY A DRIZZLE/FREEZING DRIZZLE SIGNATURE IN THERE FOR A TIME
THIS MORNING...AIDED BY LOW LEVEL CONVERGENCE AND UPSLOPE FLOW.
THIS DRIZZLE CHANCE WILL PROBABLY BE CONFINED TO JUST THE MORNING
HOURS...AS CONTINUED COLD ADVECTION WILL ALLOW CONVECTIVE BOUNDARY
LAYER TO DEEPEN ENOUGH TO SUPPORT SOME LIGHT SNOW SHOWERS/FLURRIES.
ANOTHER FEATURE TO WATCH FOR THROUGH EARLY AFTERNOON IS ANOTHER LOBE
OF MOISTURE WRAPPING SOUTHWARD INTO NORTHERN MINNESOTA ON IR
IMAGERY. THIS IS ASSOCIATED WITH ANOTHER 700MB TROUGH THAT WILL
ROTATE ACROSS LAKE SUPERIOR AND THE UPPER PENINSULA AROUND
MIDDAY...AND MAY CONTRIBUTE SOME ADDITIONAL SNOWFLAKES THROUGH EARLY
AFTERNOON. GUSTY WINDS WILL ALSO BE AN ISSUE TODAY...GIVEN STRONG
GRADIENT AND ACCOMPANYING ISALLOBARIC CONTRIBUTION...AND LOW LEVEL
COLD ADVECTION WILL HELP MIX DOWN STRONGER MOMENTUM. EXPECT WIND
GUSTS IN THE 25-35 MPH RANGE ACROSS EASTERN UPPER...AND 30-40 MPH
ACROSS NORTHERN LOWER AND POSSIBLY HIGHER ALONG THE LAKE MICHIGAN
SHORELINE COUNTIES. TEMPERATURES TODAY WILL LIKELY REMAIN STEADY OR
DROP OFF A BIT...ESPECIALLY OVER NORTHWEST LOWER WHERE TEMPERATURES
ARE AROUND 40 DEGREES TO START THE DAY AT MBL/FKS/TVC.
INCREASING HEIGHTS/DEEP LAYER ANTICYCLONIC FLOW AND ONSET OF WARM
ADVECTION WILL QUICKLY DIMINISH LINGERING LAKE CONVECTION THIS
EVENING WITH IMPRESSIVE HEIGHT RISES FOR EARLY JANUARY AS MENTIONED
ABOVE (ALMOST RIDICULOUSLY IMPRESSIVE).
.LONG TERM...(THURSDAY THROUGH TUESDAY)
ISSUED AT 405 AM EST WED JAN 9 2013
TRANSITION TOWARD A CLASSIC "JANUARY THAW" PATTERN IS NOW WELL
UNDERWAY ACROSS THE NORTHERN HEMISPHERE...WITH WATER VAPOR IMAGERY
SHOWING STRONG NORTH PACIFIC JET SOUTH OF THE BERING SEA COLLAPSING
INTO STRONG CLOSED LOW WEST OF THE ALEUTIANS. THIS IS ALREADY
SENDING DOWNSTREAM HEIGHTS RISING INTO THE GULF OF ALASKA...WHILE
STRONG UPPER TROUGHING IS SLIDING TOWARD THE WESTERN CONUS...FURTHER
SENDING DOWNSTREAM HEIGHTS RISING THROUGH THE PLAINS. THIS
TRANSITION WILL ONLY STRENGTHEN FURTHER WITH TIME THE NEXT FEW DAYS
AS A STRONG NEGATIVE PNA TYPE PATTERN BECOME ESTABLISHED WITH
PRONOUNCED MERIDIONAL TROUGHING OVER MUCH OF THE WESTERN
CONUS...WHILE IMPRESSIVE SOUTHEAST RIDGE SETUP BECOMES ESTABLISHED
OVER THE EASTERN HALF OF THE COUNTRY. SAID SETUP WILL FAVOR THE
OCCASIONAL EJECTION OF UPPER ENERGY FROM THE PARENT WESTERN
TROUGH...WHILE DEEPENING SOUTHWEST FLOW REGIME THROUGHOUT THE
TROPOSPHERE TRANSPORTS TREMENDOUSLY WARM AIR THROUGHOUT ALL AREAS
EAST OF THE MISSISSIPPI THROUGH AT LEAST THE FIRST PART OF THE
WEEKEND. THE PRIMARY FORECAST CONCERNS THROUGHOUT THE EXTENDED
REMAIN THE TIMING OF VARIOUS RAIN CHANCES...ALONG WITH JUST HOW WARM
TEMPS WILL GET FRIDAY/SATURDAY...AND HOW COLD IT MAY GET INTO EARLY
NEXT WEEK.
FIRST THINGS FIRST...THE DAYLIGHT HOURS OF THURSDAY CONTINUE TO LOOK
DRY AS SHORTWAVE LOW/MID LEVEL RIDGING BUILD OVERHEAD...IN ADVANCE
OF CLOSED OR NEGATIVE TILT UPPER TROUGH LIFTING THROUGH THE MID
MISSISSIPPI VALLEY. MARKED AXIS OF DRY AIR THROUGHOUT THE COLUMN
BELOW 600MB WILL EASILY PREVENT ANY PRECIP...THOUGH WE WILL SEE
INCREASING HIGH CLOUDS WITH TIME. STILL THINKING THIS COULD BE
YET ANOTHER SNEAKY WARM DAY AS LOW LEVEL WARM ADVECTION CRANKS UP
WHILE CLOUD COVER ONLY GRADUALLY THICKENS. GIVEN TRENDS THE PAST FEW
DAYS FOR TEMPS TO WAY OVER-PERFORM (BY SOME 4-8F ABOVE THE WARMEST
GUIDANCE)...HAVE NO CHOICE BUT TO BUMP NUMBERS UP ONCE AGAIN INTO
THE 38-46F RANGE...AND COULD BE WARMER PENDING ARRIVAL OF THICKER
CIRRUS.
THE MAIN SHOW STILL ARRIVES THURSDAY NIGHT INTO THE FIRST PART OF
FRIDAY...AS AFOREMENTIONED UPPER TROUGH SLIDES OVERHEAD. BEST QG
FORCING AXIS LOOKS TO SLIDE SOUTH OF THE AREA...BUT STRONG PUSH OF
DEEP LAYER WARM ADVECTION ASCENT WILL EASILY COMPENSATE...WITH SOME
40-50 KNOTS PERPENDICULAR TO THE PRESSURE SURFACES INDICATIVE OF
IMPRESSIVE LIFT...ESPECIALLY WHEN COMBINED WITH PWATS OVER AN INCH.
INTERESTINGLY...THESE MOISTURE VALUES ARE EASILY ABOVE THE 99TH
PERCENTILE FOR THIS TIME OF YEAR...AND IF THE NAM/GFS VALUES UP
AROUND 1.10 INCHES VERIFY AT 12Z FRIDAY...THIS WILL BE A NEW PWAT
RECORD FOR THE APX SITE FOR JANUARY!! SIMPLY PUT...IT`S GOING TO
RAIN AND GOING 100 PERCENT POPS WILL REMAIN. STILL SOME SMALL
POTENTIAL FOR FREEZING RAIN AT THE ONSET ACROSS THE HIGHER TERRAIN
AND INTO THE EASTERN U.P...BUT HONESTLY BECOMING LESS IMPRESSED BY
THIS POSSIBILITY GIVEN EXPECTED WARMER START THROUGH THE EVENING.
SREF PRECIP TYPE GUIDANCE AGREES WITH A STARK REDUCTION IN FZRA
PROBS THE PAST 24 HOURS...BUT CAN`T COMPLETELY RULE IT OUT...
ESPECIALLY WITH SOME COLDER ROAD SURFACES DIRECTLY AT THE GROUND.
SYNOPTIC RAIN WILL TAPER OFF QUICKLY BY MIDDAY FRIDAY WITH LOSS OF
FORCING FOR ASCENT...LEAVING IS IN NO-MAN`S LAND INTO EARLY
SATURDAY...OUT AHEAD OF A STRONGER WAVE LIFTING FROM THE CENTRAL
PLAINS THROUGH THE UPPER MIDWEST. THIS PERIOD WILL NO DOUBT CONTINUE
TO BE MILD...WITH UNOBSTRUCTED DEEP LAYER SOUTHWESTERLY FLOW KICKING
DEW POINTS WELL INTO THE 40S...WITH TEMPS FOLLOWING SUIT. BIGGEST
QUESTION IS JUST HOW MUCH STRATUS/FOG/DRIZZLE WILL BE POSSIBLE AS
WARMTH CUTS ACROSS REMAINING SNOW PACK. NORMALLY REALLY LIKE TO SEE
A WARM FRONT TO FOCUS FOG/STRATUS POTENTIAL AND WE WON`T HAVE THAT
(IT`S WAY UP INTO ONTARIO). INSTEAD WE WILL HAVE QUITE STRONG
SYNOPTIC SOUTHERLY FLOW CUTTING THROUGH THE AREA. NO DOUBT WE WILL
SEE SOME DEGREE OF LIGHT FOG AND/OR HAZE AS SNOW MELT
CONTINUES...BUT NO TOTALLY SOLD THAT WE WILL ALSO BE ENCASED IN
WIDESPREAD STRATUS THE WHOLE TIME. NAM/GFS FCST RAOBS ARE USELESS AS
THEY CAN`T WARM OVER THE SNOW PACK...BUT ECMWF/GGEM GUIDANCE (WHICH
HAVE NO TROUBLE WARMING OVER SNOW PACK) CONTINUES TO SUGGEST WE
MIGHT SHED THE LOW STUFF FOR A WHILE AS TEMPS CONTINUE TO RISE
THROUGH THE 40S...IF NOT LOW 50S. NOT REALLY A HUGE DEAL...BUT WILL
BE AN INTERESTING FORECAST TO WATCH UNFOLD.
AFTER THAT...FOCUS WILL BE ON THE EVOLUTION OF A QUITE POTENT COLD
FRONT SATURDAY INTO SATURDAY NIGHT AS THE ENTIRE WESTERN TROUGH
GRADUALLY WORKS EAST. AS MENTIONED IN THIS SPACE YESTERDAY...NOT
COMPLETELY SOLD THAT WE WILL SEE ANY ADDITIONAL SIGNIFICANT PRECIP
WITH THE ACTUAL FRONTAL APPROACH...AS FORCING WITH THE UPPER WAVE
SHEARS OUT INTO WESTERN ONTARIO WHILE DEEPER LAYER WARM ADVECTION
ASCENT AND JET HELP SLIDE THROUGH THE TENNESSEE AND OHIO VALLEYS.
CAN EASILY ENVISION A SCENARIO WHERE NORTHERN MICHIGAN IS SPLIT...
AND IN FACT...JUST ABOUT ALL THE LATEST AVAILABLE GUIDANCE SUPPORTS
THIS NOTION. TEMPS ON SATURDAY ARE TRICKY WITH THE POTENTIAL FOR A
VERY WARM DAY IN SPOTS AHEAD OF THE FRONT. 12Z ECMWF SPED UP THE
FRONTAL PASSAGE BY ABOUT 6 HOURS (MIDDAY SATURDAY)...WHILE OTHER
GUIDANCE REMAINS A BIT SLOWER. TRENDS IN THIS SETUP ALMOST ALWAYS
ARE SLOWER AS THE FLOW ALOFT PARALLELS THE SURFACE FEATURE...SO WILL
SIDE WITH YET ANOTHER VERY WARM DAY SATURDAY WITH HIGHS LIKELY
PUSHING 50 OR BETTER IN SPOTS (RECORDS ARE IN JEOPARDY IN SPOTS -
SEE BELOW FOR DETAILS)).
WHAT HAPPENS THEREAFTER IS MUCH IN QUESTION...BUT COLDER WEATHER
DOES LOOK TO MAKE AN APPEARANCE. LOTS OF JET ENERGY POURING DOWN
THE SPINE OF THE ROCKIES COMBINED WITH A STRONG SOUTHEAST RIDGE DOES
ARGUE THE WESTERN TROUGH WILL ONLY SLOWLY WORK EASTWARD...SETTING UP
A STRONG BAROCLINIC ZONE SOMEWHERE NEARBY. GUIDANCE TRENDS THE PAST
5-7 DAYS HAVE SUGGESTED THIS ZONE WILL BE EAST OF MICHIGAN...AND
SADLY FOR THE WINTER WEATHER FANS...THE LATEST GUIDANCE TRENDS ALSO
SUPPORT THIS...LEAVING THE CORE OF THE UPPER JET SQUARELY OVER
NORTHERN MICHIGAN...NEVER A GOOD PLACE TO BE IF YOU WANT WEATHER.
COULD SEE SOME PESKY LAKE EFFECT...BUT AIR MASS IS PROGGED TO BE VERY
DRY AND JUST NOT FEELING THIS AS A BIG EVENT...WITH TRENDS TENDING
TO SUPPORT A GRADUAL MODIFICATION TO THE LOW LEVEL AIR MASS WITH TIME
AS WELL. NOW...WITH THAT SAID...I`M NOT TOTALLY SOLD THAT WE WON`T
AT LEAST CATCH A LITTLE SYNOPTIC SNOW AS THE MODELS ARE NOTORIOUSLY
BAD AT PLACING SUCH STRONG THERMAL ZONES THIS FAR OUT. OF MORE
INTEREST REMAINS THE ONGOING VERY STRONG (NEAR HISTORIC VALUES BEING
OBSERVED CURRENTLY) STRATOSPHERIC WARMING EVENT THAT HAS MARCHED
FROM THE HIMALAYAS TOWARD THE ARCTIC...WITH MEDIUM RANGE MODELS
FINALLY CATCHING ONTO THE POSSIBILITY THAT SOME TRULY COLD AIR MAY
BE DRAWN DOWN INTO THE AREA AS THE POLAR VORTEX DISLODGES DOWN INTO
CANADA LATE NEXT WEEK OR JUST BEYOND. DEFINITELY SOMETHING TO WATCH
HERE.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z THURSDAY AFTERNOON)
ISSUED AT 1247 PM EST WED JAN 9 2013
THERE ARE ENOUGH HOLES IN THE CIGS AND THE CIGS THEMSELVES VARY
ENOUGH THAT THERE ARE MVFR AND VFR CIGS AT THE TAF SITES. THIS
WILL CONTINUE WITH THE STRONG WINDS TO AROUND 00Z. AFTER 00Z, THE
WINDS WILL DIMINISH AS THE GRADIENT RELAXES THIS EVENING, AND THE
CLOUD COVER WILL CLEAR OUT AS THE DRIER AIR IN THE MID LEVELS
MOVES THROUGH N MICHIGAN TONIGHT. WITH THE HIGH PRESSURE MOVING
INTO THE REGION OVERNIGHT THE START OF THE DAY ON THURSDAY WILL BE
VFR.
&&
.MARINE...
ISSUED AT 405 AM EST WED JAN 9 2013
GALE WARNINGS AND SMALL CRAFT ADVISORIES ALREADY IN EFFECT THIS
MORNING FOR ANTICIPATED WINDS TODAY THROUGH THIS EVENING. ONLY
CHANGE TO HEADLINES THAT MAY BE NEEDED IS AN UPGRADE TO A GALE
WARNING FOR WHITEFISH BAY STARTING THIS AFTERNOON. A RIDGE OF HIGH
PRESSURE WILL BUILD INTO THE UPPER GREAT LAKES TONIGHT...WHICH WILL
ALLOW WINDS TO GRADUALLY RAMP DOWN AS THE NIGHT PROGRESSES WHILE
BACKING TO A MORE SOUTHERLY COMPONENT.
&&
.CLIMATE...
ISSUED AT 405 AM EST WED JAN 9 2013
BELOW IS A LOOK AT THE CURRENT RECORD HIGHS FOR BOTH FRIDAY AND
SATURDAY. AS TALKED ABOUT IN THE DISCUSSION ABOVE...SOME OF THESE
MAY WELL BE IN JEOPARDY. THE THURSDAY RECORD IN GAYLORD MAY ALSO BE
MET OR TIED IF ENOUGH SUNSHINE CAN MAKE AN APPEARANCE...CURRENTLY
SITTING AT 42 DEGREES FROM 1972. ALSO...IT IS NOT COMPLETELY
IMPOSSIBLE WE COULD APPROACH THE ALL-TIME JANUARY RECORD HIGH AT
GAYLORD...WHICH IS 53 DEGREES SET IN 1996 AND 1973.
LOCATION FRIDAY RECORD (1/11) SATURDAY RECORD (1/12)
------------------------------------------------------------
ALPENA 50 FROM 2012 49 FROM 2005
GAYLORD 47 FROM 1980 45 FROM 2005
PELLSTON 49 FROM 1975 45 FROM 2005
TRAVERSE CITY 53 FROM 2012 50 FROM 2006
HOUGHTON LAKE 50 FROM 2012 47 FROM 2005
SAULT STE MARIE 44 FROM 1980 43 FROM 1932
&&
.APX WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LH...GALE WARNING UNTIL 4 PM EST THIS AFTERNOON FOR LHZ345.
GALE WARNING UNTIL 11 PM EST THIS EVENING FOR LHZ346>349.
LM...GALE WARNING UNTIL 4 PM EST THIS AFTERNOON FOR LMZ323-341-342-
344>346.
LS...SMALL CRAFT ADVISORY UNTIL 4 PM EST THIS AFTERNOON FOR LSZ322.
GALE WARNING UNTIL 11 PM EST THIS EVENING FOR LSZ321.
&&
$$
UPDATE...JL
SYNOPSIS...DML
SHORT TERM...JPB
LONG TERM...DML
AVIATION...JL
CLIMATE...DML
MARINE...JPB
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
1224 PM EST WED JAN 9 2013
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 526 AM EST WED JAN 9 2013
WATER VAPOR IMAGERY AND RUC ANALYSIS SHOW A CONTINUED PROGRESSIVE
NRN STREAM ACROSS THE NRN CONUS/SRN CANADA. SHORTWAVE TROF IS
CURRENTLY MOVING OVER THE WRN GREAT LAKES. AT THE SFC...ASSOCIATED
LOW PRES IS OVER NRN ONTARIO. DESPITE RATHER VIGOROUS LOOK OF
SHORTWAVE...VERY LITTLE PCPN HAS OCCURRED OVER THE FCST AREA
OVERNIGHT. SOME PCPN PROBABLY OCCURRED OVER LAKE SUPERIOR PER RADAR
IMAGERY. OVER UPPER MI...NARROW BAND OF PCPN APPEARED TO DEVELOP
OVER THE ERN FCST AREA BTWN 07-09Z...BUT ONLY OB TO REPORT ANY PCPN
WAS AT KERY AND THAT WAS -RA.
FOCUS TODAY SHIFTS TO WINDS AND -SHSN CHANCES IN THE WAKE OF
SHORTWAVE. WEST WINDS WILL BE INCREASING ACROSS THE KEWEENAW OVER
THE NEXT SEVERAL HRS AS CAA INCREASES INSTABILITY/BUILDS MIXING
DEPTH TOWARD THE 45-50KT LOW-LEVEL WIND MAX AT 2-4KFT. COMBINED WITH
IDEAL WNW WIND DIRECTION FOR STRONG WINDS MAKES WIND ADVY ON THE
KEWEENAW AN OBVIOUS CALL. EXPECT STRONGEST WINDS TO OCCUR MID
MORNING INTO EARLY AFTN JUST AHEAD OF APPROACHING AREA OF 5MB/3HR
PRES RISES WHICH IS NOW OVER NE ND/FAR NW MN. GUSTS OF 45-50MPH
APPEAR LIKELY DURING THAT TIME. FARTHER S...WINDS ALONG THE SHORE
TOWARD ONTONAGON/SILVER CITY WILL BE CLOSE TO 45MPH. TO THE E...
SHORELINE LOCATIONS FROM PICTURED ROCKS EASTWARD WILL ALSO SEE GUSTS
TO AROUND 45 MPH. W WINDS SHOULD KEEP THESE HIGHER GUSTS CONFINED
MOSTLY TO THE BEACHES/SHORELINE. ELSEWHERE...IT WILL BE A BREEZY DAY
WITH WIND GUSTS GENERALLY IN THE 25 TO 35 MPH RANGE.
AS FOR PCPN...850MB TEMPS FALLING BRIEFLY TO AROUND -10C WILL BE
MARGINAL FOR LES OFF LAKE SUPERIOR. HOWEVER...SINCE THERE IS A SMALL
AREA OF -SN MOVING ACROSS NRN MN ATTM...EXPECT SOME -SHSN ON THE
KEWEENAW FOR A PORTION OF THE MORNING INTO EARLY AFTN...AND OVER THE
FAR NE FCST AREA DURING THE AFTN. A COUPLE OF OBS IN NRN MN HAVE
DROPPED TO AROUND 1SM...SO THERE CERTAINLY COULD BE A BRIEF PERIOD
OF HEAVIER SHSN. WILL BE SOMETHING TO MONITOR. RIGHT NOW...IT
APPEARS SNOW ACCUMULATIONS WILL BE UNDER AN INCH.
ALTHOUGH THERE WILL BE A TREND TOWARD CLEARING SKIES AWAY FROM THE
KEWEENAW AND FAR NE FCST AREA...CAA THRU MID DAY WILL LIMIT TEMP
RISE. MAX TEMPS SHOULDN`T BE TOO MUCH HIGHER THAN CURRENT READINGS.
30S WILL BE THE RULE.
SFC HIGH PRES RIDGE QUICKLY SHIFTS ACROSS UPPER MI TONIGHT. WITH
SKIES TRENDING TOWARD MAINLY CLEAR...THERE WILL BE A WINDOW FOR
TEMPS TO FALL SHARPLY UNDER A BRIEF PERIOD OF LIGHT/CALM WIND BEFORE
RETURN FLOW DEVELOPS. INDICATED MINS AS LOW AS THE LOW TEENS IN SOME
OF THE TRADITIONAL COLD SPOTS...BUT WOULDN`T BE SURPRISED TO SEE A
FEW SPOTS FALL INTO THE SINGLE DIGITS.
.LONG TERM...(THURSDAY THROUGH TUESDAY)
ISSUED AT 526 AM EST WED JAN 9 2013
A CONTINUED ACTIVE PATTERN WILL BE THE RULE THROUGH THE WEEKEND AS
MULTIPLE TROUGHS ARE PROGGED TO CROSS THE UPPER GREAT
LAKES...BRINGING WELL ABOVE NORMAL TEMPERATURES AND APPRECIABLE RAIN
FOR THE EAST HALF OF THE CWA.
THURSDAY AND THURSDAY NIGHT...THE UPPER GREAT LAKES AND MIDWEST WILL
BE UNDER THE INFLUENCE OF A PRONOUNCED MID-LEVEL TROUGH. THE LAYER
SHOULD BE FAIRLY DRY AND ALLOW FOR ABUNDANT SUNSHINE ACROSS THE CWA.
MEANWHILE...SOUTHERLY RETURN FLOW AHEAD OF AN APPROACHING
MID-LEVEL/SFC LOW OVER THE MID-MS VALLEY WILL BRING INCREASING WINDS
AND THIN...HIGH CIRRUS CLOUDS IN THE AFTERNOON. EXPECTATION IS THAT
MOSTLY SUNNY SKIES AND THE LOWER ALBEDO OF THE DENSE UPPER MI
FORESTS WILL RESULT IN TEMPS WELL-ABOVE NORMAL...AND EVEN SLIGHTLY
ABOVE CURRENT GUIDANCE. KEPT FORECAST VERY SIMILAR TO PREVIOUS
SHIFT...WITH UPPER 30S ACROSS MUCH OF THE INTERIOR AND LOW 40S FOR
DOWNSLOPE LOCATIONS ALONG LAKE SUPERIOR. SOME LOCATIONS WILL
APPROACH RECORD HIGHS IF DOWNSLOPE INFLUENCE IS STRONGER THAN
ANTICIPATED.
NOW ONTO THE SYSTEM TAKING AIM ON THE AREA THURSDAY NIGHT. A COMPACT
MID-LEVEL CUTOFF LOW NEAR THE GREAT BEND OF TEXAS IS BEGINNING ITS
TURN NORTHEASTWARD AND IS SET TO REACH THE MID-MS VALLEY BY LATE
THURSDAY NIGHT. MODEL AGREEMENT ON THIS SYSTEM HAS BECOME VERY GOOD
WITH THE EXCEPTION OF THE GFS...WHICH HAS BEEN TRENDING SLOWER. WILL
STICK WITH THE MORE CONSISTENT ECMWF/GEM SOLUTION.
THOUGH THE MAIN MID-LEVEL FORCING WITH THE SHORTWAVE WILL PASS JUST
TO THE SOUTHEAST OF THE CWA...DECENT ISENTROPIC LIFT ON THE 295-305K
SURFACES AND CONSIDERABLE LOW-LEVEL MOISTURE TRANSPORT ON THE NOSE
OF A 60KT H8 JET WILL SUPPORT MODERATE RAIN OVER THE EAST HALF OF
THE CWA. MOISTURE CONTENT OF THE COLUMN WILL BE AN IMPRESSIVE
1.1"/450 PERCENT OF NORMAL. GIVEN THE SET-UP AND HIGH WATER CONTENT
FOR JANUARY...HAVE CONTINUED THE TREND OF BUMPING UP POPS TO
WIDESPREAD RAIN ACROSS THE EASTERN TWO-THIRDS OF THE CWA BEGINNING
LATE THURSDAY EVENING. HELD OFF POPS FOR ALL BUT THE SOUTH-CENTRAL
CWA UNTIL THIS TIME. STORM TOTAL QPF OF A HALF INCH OR MORE FOR THE
EAST HALF SEEMS REASONABLE ATTM.
AS FOR PRECIP TYPE...TEMPERATURES ACROSS THE INTERIOR WEST AND
CENTRAL MAY FALL BELOW FREEZING IN THE EVENING BEFORE THICKER CLOUDS
AND WAA TAKE CONTROL AND WARM TEMPS BACK ABOVE FREEZING. INITIAL
RAIN WILL BE FALLING INTO QUITE A DRY LAYER...WITH SFC WET-BULB
TEMPS JUST UNDER FREEZING. HOWEVER...GIVEN WARM HIGHS AND
CONSIDERABLE SUNSHINE THURSDAY...A NARROW WINDOW OF BELOW FREEING
TEMPS...AND WARM RAIN FROM A 6 TO 8C WARM LAYER ABOVE THE SFC...ONLY
PUT IN A SLIGHT CHANCE OF FREEZING RAIN MAINLY INTERIOR CENTRAL. NOT
REALLY EXPECTING ANY ICING...BUT DID WANT TO PUT A SMALL MENTION IN
THERE.
FRIDAY THROUGH FRIDAY NIGHT...PRECIP WILL CONTINUE ACROSS THE EAST
HALF FRIDAY MORNING AS THE INFLUX OF MOISTURE CONTINUES OVER THE
AREA. A SECONDARY DEEP TROUGH MOVING INTO THE ROCKIES FRIDAY
AFTERNOON WILL BEGIN TO LIFT NORTHEASTWARD BY FRIDAY EVENING. IN
COMBINATION WITH THE LEFT EXIT OF A 140KT UPPER JET OVER THE
UPPER-MS VALLEY...A SFC LOW WILL QUICKLY FORM OVER MN FRIDAY NIGHT.
THERE SHOULD BE A LAPSE IN PRECIP FOR ALL BUT THE WESTERN CWA FRIDAY
NIGHT AS PLENTY OF DRY AIR IS DRAWN INTO THE REGION AHEAD OF THE
TROUGH/SFC LOW. SOME DRIZZLE IS POSSIBLE WITHIN A THICK LOW-LEVEL
STRATUS DECK WHERE RAIN SHOWERS MAY NOT BE AS PREVALENT CENTRAL AND
EAST. ALSO HAVE AREAS OF FOG IN THE FORECAST GIVEN RELATIVELY
WARM/MOIST AIR FLOWING OVER MELTING SNOW.
SATURDAY...AS THE SURFACE LOW TRACKS OVER LAKE SUPERIOR LATE FRIDAY
NIGHT INTO SATURDAY...IT WILL DRAW DOWN COLDER AIR FROM CANADA AND
SWEEP A COLD FRONT ACROSS THE CWA. HIGHS WILL LIKELY BE EARLY IN THE
DAY AS TEMPERATURES WILL QUICKLY FALL AT MOST LOCATIONS BY THE
AFTERNOON. EXPECT ANY RAIN SHOWERS TO TRANSITION TO SNOW SHOWERS
FROM WEST TO EAST THROUGHOUT THE DAY. ONLY MINOR ACCUMULATIONS ARE
EXPECTED AS MID/UPPER LEVEL SUPPORT WILL BE NORTH OF THE CWA AND
DECENT H5 Q-VECTOR DIVERGENCE WILL BE PASSING OVER THE CWA.
SATURDAY NIGHT THROUGH TUESDAY...DID NOT MAKE MANY CHANGES PAST THIS
POINT. LAKE EFFECT SNOW LOOKS LIKELY FOR THE KEWEENAW AND FAR
NORTHEAST SATURDAY NIGHT THROUGH SUNDAY WITH WNW WINDS. A CORE OF
-17 TO -19C AIR GETS WRAPPED AROUND THE DEPARTING LOW AND CROSSES
LAKE SUPERIOR SATURDAY NIGHT. INVERSION HEIGHTS SHOULD STAY BETWEEN
4-5 KFT THROUGH MUCH OF SUNDAY UNDERNEATH SUBSIDENCE BEHIND THE
DEPARTING TROUGH. THOSE HEIGHTS THEN FALL UNDER 3 KFT AND DRY AIR
ADVECTS INTO THE REGION FROM THE SW SUNDAY NIGHT...THEREBY
DECREASING LES COVERAGE BY MONDAY. TEMPERATURES THEN REMAIN AROUND
SEASONAL NORMS TO START NEXT WEEK WITH MINIMAL PRECIP CHANCES.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z THURSDAY AFTERNOON)
ISSUED AT 1223 PM EST WED JAN 9 2013
A STRONG PRESSURE GRADIENT BETWEEN A LOW NEAR HUDSON BAY AND A HIGH
IN MINNESOTA WILL CONTINUE TO PRODUCE GUSTY WINDS THIS AFTERNOON AT
ALL TAF SITES. THE STRONGEST WINDS WILL CONTINUE TO BE AT
KCMX...WHERE GUSTS TO 45-55MPH HAVE BEEN OCCURRING. EXPECT THE WINDS
TO DECREASE LATER THIS AFTERNOON AS THE HIGH PRESSURE RIDGE SHIFTS
OVER THE AREA. OTHER THAN LINGERING LAKE EFFECT SNOW AND CLOUDS AT
THIS EVENING...DECREASING CLOUDS ARE IN STORE FOR ALL SITES OVER THE
NEXT 3-9HOURS. THE HIGH PRESSURE RIDGE WILL THEN PRODUCE VFR
CONDITIONS TONIGHT INTO THURSDAY.
ONE FINAL ITEM OF NOTE...AN INCREASING LOW LEVEL JET ABOVE THE
INVERSION IS EXPECTED TOMORROW MORNING...UP TO 45-50KTS AROUND 1KFT
ABOVE THE SURFACE. OPTED TO ADD IN A MENTION OF LLWS AT KIWD/KCMX
SINCE THE INVERSION SHOULD KEEP SURFACE WINDS TOMORROW MORNING
AROUND 10KTS.
&&
.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 526 AM EST WED JAN 9 2013
IN THE WAKE OF COLD FRONT PASSING ACROSS LAKE SUPERIOR THIS
MORNING...EXPECT W GALES OF 35-45KT TODAY. HIGH OBS PLATFORMS MAY
HAVE A COUPLE OF HRS OF GUSTS TO STORM FORCE JUST AHEAD OF 5MB/3HR
PRES RISES THAT WILL SHIFT ACROSS THE AREA TODAY. WINDS WILL QUICKLY
DIMINISH TO UNDER 20KT W TO E TONIGHT AS SFC HIGH PRES RIDGE MOVES
ACROSS LAKE SUPERIOR. INCREASING SOUTHERLY WINDS TO 20 TO 30 KNOTS
AHEAD OF AN APPROACHING LOW PRESSURE IN THE MID-MISSISSIPPI VALLEY
WILL AFFECT MAINLY THE EAST HALF OF LAKE SUPERIOR THURSDAY AND
THURSDAY NIGHT. LIGHT SOUTHERLY WINDS WILL THEN TAKE HOLD FRIDAY
BEFORE A COLD FRONT SWEEPS ACROSS THE LAKE FROM WEST TO EAST ON
SATURDAY. WESTERLY WINDS OF 25 TO 30 KNOTS WILL DEVELOP BY SATURDAY
AFTERNOON AND CONTINUE INTO EARLY SATURDAY EVENING. A FEW GALES TO 35
KNOTS WILL BE POSSIBLE ACROSS THE EAST HALF OF THE LAKE LATE SATURDAY
AFTERNOON. THE PATTERN BECOMES QUITE BENIGN BY SUNDAY...WITH MAINLY
WESTERLY WINDS UNDER 20 KNOTS THROUGH THE REMAINDER OF THE PERIOD.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
WIND ADVISORY UNTIL 5 PM EST THIS AFTERNOON FOR MIZ001-003.
LAKE SUPERIOR...
GALE WARNING UNTIL 10 PM EST THIS EVENING FOR LSZ249>251-266-267.
GALE WARNING UNTIL 7 PM EST THIS EVENING FOR LSZ243>248-264-265.
GALE WARNING UNTIL 4 PM EST /3 PM CST/ THIS AFTERNOON FOR LSZ162-
240>242-263.
LAKE MICHIGAN...
GALE WARNING UNTIL 4 PM EST THIS AFTERNOON FOR LMZ221-248-250.
&&
$$
SHORT TERM...ROLFSON
LONG TERM...TK
AVIATION...SRF
MARINE...ROLFSON/TK
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
649 AM EST WED JAN 9 2013
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 526 AM EST WED JAN 9 2013
WATER VAPOR IMAGERY AND RUC ANALYSIS SHOW A CONTINUED PROGRESSIVE
NRN STREAM ACROSS THE NRN CONUS/SRN CANADA. SHORTWAVE TROF IS
CURRENTLY MOVING OVER THE WRN GREAT LAKES. AT THE SFC...ASSOCIATED
LOW PRES IS OVER NRN ONTARIO. DESPITE RATHER VIGOROUS LOOK OF
SHORTWAVE...VERY LITTLE PCPN HAS OCCURRED OVER THE FCST AREA
OVERNIGHT. SOME PCPN PROBABLY OCCURRED OVER LAKE SUPERIOR PER RADAR
IMAGERY. OVER UPPER MI...NARROW BAND OF PCPN APPEARED TO DEVELOP
OVER THE ERN FCST AREA BTWN 07-09Z...BUT ONLY OB TO REPORT ANY PCPN
WAS AT KERY AND THAT WAS -RA.
FOCUS TODAY SHIFTS TO WINDS AND -SHSN CHANCES IN THE WAKE OF
SHORTWAVE. WEST WINDS WILL BE INCREASING ACROSS THE KEWEENAW OVER
THE NEXT SEVERAL HRS AS CAA INCREASES INSTABILITY/BUILDS MIXING
DEPTH TOWARD THE 45-50KT LOW-LEVEL WIND MAX AT 2-4KFT. COMBINED WITH
IDEAL WNW WIND DIRECTION FOR STRONG WINDS MAKES WIND ADVY ON THE
KEWEENAW AN OBVIOUS CALL. EXPECT STRONGEST WINDS TO OCCUR MID
MORNING INTO EARLY AFTN JUST AHEAD OF APPROACHING AREA OF 5MB/3HR
PRES RISES WHICH IS NOW OVER NE ND/FAR NW MN. GUSTS OF 45-50MPH
APPEAR LIKELY DURING THAT TIME. FARTHER S...WINDS ALONG THE SHORE
TOWARD ONTONAGON/SILVER CITY WILL BE CLOSE TO 45MPH. TO THE E...
SHORELINE LOCATIONS FROM PICTURED ROCKS EASTWARD WILL ALSO SEE GUSTS
TO AROUND 45 MPH. W WINDS SHOULD KEEP THESE HIGHER GUSTS CONFINED
MOSTLY TO THE BEACHES/SHORELINE. ELSEWHERE...IT WILL BE A BREEZY DAY
WITH WIND GUSTS GENERALLY IN THE 25 TO 35 MPH RANGE.
AS FOR PCPN...850MB TEMPS FALLING BRIEFLY TO AROUND -10C WILL BE
MARGINAL FOR LES OFF LAKE SUPERIOR. HOWEVER...SINCE THERE IS A SMALL
AREA OF -SN MOVING ACROSS NRN MN ATTM...EXPECT SOME -SHSN ON THE
KEWEENAW FOR A PORTION OF THE MORNING INTO EARLY AFTN...AND OVER THE
FAR NE FCST AREA DURING THE AFTN. A COUPLE OF OBS IN NRN MN HAVE
DROPPED TO AROUND 1SM...SO THERE CERTAINLY COULD BE A BRIEF PERIOD
OF HEAVIER SHSN. WILL BE SOMETHING TO MONITOR. RIGHT NOW...IT
APPEARS SNOW ACCUMULATIONS WILL BE UNDER AN INCH.
ALTHOUGH THERE WILL BE A TREND TOWARD CLEARING SKIES AWAY FROM THE
KEWEENAW AND FAR NE FCST AREA...CAA THRU MID DAY WILL LIMIT TEMP
RISE. MAX TEMPS SHOULDN`T BE TOO MUCH HIGHER THAN CURRENT READINGS.
30S WILL BE THE RULE.
SFC HIGH PRES RIDGE QUICKLY SHIFTS ACROSS UPPER MI TONIGHT. WITH
SKIES TRENDING TOWARD MAINLY CLEAR...THERE WILL BE A WINDOW FOR
TEMPS TO FALL SHARPLY UNDER A BRIEF PERIOD OF LIGHT/CALM WIND BEFORE
RETURN FLOW DEVELOPS. INDICATED MINS AS LOW AS THE LOW TEENS IN SOME
OF THE TRADITIONAL COLD SPOTS...BUT WOULDN`T BE SURPRISED TO SEE A
FEW SPOTS FALL INTO THE SINGLE DIGITS.
.LONG TERM...(THURSDAY THROUGH TUESDAY)
ISSUED AT 526 AM EST WED JAN 9 2013
A CONTINUED ACTIVE PATTERN WILL BE THE RULE THROUGH THE WEEKEND AS
MULTIPLE TROUGHS ARE PROGGED TO CROSS THE UPPER GREAT
LAKES...BRINGING WELL ABOVE NORMAL TEMPERATURES AND APPRECIABLE RAIN
FOR THE EAST HALF OF THE CWA.
THURSDAY AND THURSDAY NIGHT...THE UPPER GREAT LAKES AND MIDWEST WILL
BE UNDER THE INFLUENCE OF A PRONOUNCED MID-LEVEL TROUGH. THE LAYER
SHOULD BE FAIRLY DRY AND ALLOW FOR ABUNDANT SUNSHINE ACROSS THE CWA.
MEANWHILE...SOUTHERLY RETURN FLOW AHEAD OF AN APPROACHING
MID-LEVEL/SFC LOW OVER THE MID-MS VALLEY WILL BRING INCREASING WINDS
AND THIN...HIGH CIRRUS CLOUDS IN THE AFTERNOON. EXPECTATION IS THAT
MOSTLY SUNNY SKIES AND THE LOWER ALBEDO OF THE DENSE UPPER MI
FORESTS WILL RESULT IN TEMPS WELL-ABOVE NORMAL...AND EVEN SLIGHTLY
ABOVE CURRENT GUIDANCE. KEPT FORECAST VERY SIMILAR TO PREVIOUS
SHIFT...WITH UPPER 30S ACROSS MUCH OF THE INTERIOR AND LOW 40S FOR
DOWNSLOPE LOCATIONS ALONG LAKE SUPERIOR. SOME LOCATIONS WILL
APPROACH RECORD HIGHS IF DOWNSLOPE INFLUENCE IS STRONGER THAN
ANTICIPATED.
NOW ONTO THE SYSTEM TAKING AIM ON THE AREA THURSDAY NIGHT. A COMPACT
MID-LEVEL CUTOFF LOW NEAR THE GREAT BEND OF TEXAS IS BEGINNING ITS
TURN NORTHEASTWARD AND IS SET TO REACH THE MID-MS VALLEY BY LATE
THURSDAY NIGHT. MODEL AGREEMENT ON THIS SYSTEM HAS BECOME VERY GOOD
WITH THE EXCEPTION OF THE GFS...WHICH HAS BEEN TRENDING SLOWER. WILL
STICK WITH THE MORE CONSISTENT ECMWF/GEM SOLUTION.
THOUGH THE MAIN MID-LEVEL FORCING WITH THE SHORTWAVE WILL PASS JUST
TO THE SOUTHEAST OF THE CWA...DECENT ISENTROPIC LIFT ON THE 295-305K
SURFACES AND CONSIDERABLE LOW-LEVEL MOISTURE TRANSPORT ON THE NOSE
OF A 60KT H8 JET WILL SUPPORT MODERATE RAIN OVER THE EAST HALF OF
THE CWA. MOISTURE CONTENT OF THE COLUMN WILL BE AN IMPRESSIVE
1.1"/450 PERCENT OF NORMAL. GIVEN THE SET-UP AND HIGH WATER CONTENT
FOR JANUARY...HAVE CONTINUED THE TREND OF BUMPING UP POPS TO
WIDESPREAD RAIN ACROSS THE EASTERN TWO-THIRDS OF THE CWA BEGINNING
LATE THURSDAY EVENING. HELD OFF POPS FOR ALL BUT THE SOUTH-CENTRAL
CWA UNTIL THIS TIME. STORM TOTAL QPF OF A HALF INCH OR MORE FOR THE
EAST HALF SEEMS REASONABLE ATTM.
AS FOR PRECIP TYPE...TEMPERATURES ACROSS THE INTERIOR WEST AND
CENTRAL MAY FALL BELOW FREEZING IN THE EVENING BEFORE THICKER CLOUDS
AND WAA TAKE CONTROL AND WARM TEMPS BACK ABOVE FREEZING. INITIAL
RAIN WILL BE FALLING INTO QUITE A DRY LAYER...WITH SFC WET-BULB
TEMPS JUST UNDER FREEZING. HOWEVER...GIVEN WARM HIGHS AND
CONSIDERABLE SUNSHINE THURSDAY...A NARROW WINDOW OF BELOW FREEING
TEMPS...AND WARM RAIN FROM A 6 TO 8C WARM LAYER ABOVE THE SFC...ONLY
PUT IN A SLIGHT CHANCE OF FREEZING RAIN MAINLY INTERIOR CENTRAL. NOT
REALLY EXPECTING ANY ICING...BUT DID WANT TO PUT A SMALL MENTION IN
THERE.
FRIDAY THROUGH FRIDAY NIGHT...PRECIP WILL CONTINUE ACROSS THE EAST
HALF FRIDAY MORNING AS THE INFLUX OF MOISTURE CONTINUES OVER THE
AREA. A SECONDARY DEEP TROUGH MOVING INTO THE ROCKIES FRIDAY
AFTERNOON WILL BEGIN TO LIFT NORTHEASTWARD BY FRIDAY EVENING. IN
COMBINATION WITH THE LEFT EXIT OF A 140KT UPPER JET OVER THE
UPPER-MS VALLEY...A SFC LOW WILL QUICKLY FORM OVER MN FRIDAY NIGHT.
THERE SHOULD BE A LAPSE IN PRECIP FOR ALL BUT THE WESTERN CWA FRIDAY
NIGHT AS PLENTY OF DRY AIR IS DRAWN INTO THE REGION AHEAD OF THE
TROUGH/SFC LOW. SOME DRIZZLE IS POSSIBLE WITHIN A THICK LOW-LEVEL
STRATUS DECK WHERE RAIN SHOWERS MAY NOT BE AS PREVALENT CENTRAL AND
EAST. ALSO HAVE AREAS OF FOG IN THE FORECAST GIVEN RELATIVELY
WARM/MOIST AIR FLOWING OVER MELTING SNOW.
SATURDAY...AS THE SURFACE LOW TRACKS OVER LAKE SUPERIOR LATE FRIDAY
NIGHT INTO SATURDAY...IT WILL DRAW DOWN COLDER AIR FROM CANADA AND
SWEEP A COLD FRONT ACROSS THE CWA. HIGHS WILL LIKELY BE EARLY IN THE
DAY AS TEMPERATURES WILL QUICKLY FALL AT MOST LOCATIONS BY THE
AFTERNOON. EXPECT ANY RAIN SHOWERS TO TRANSITION TO SNOW SHOWERS
FROM WEST TO EAST THROUGHOUT THE DAY. ONLY MINOR ACCUMULATIONS ARE
EXPECTED AS MID/UPPER LEVEL SUPPORT WILL BE NORTH OF THE CWA AND
DECENT H5 Q-VECTOR DIVERGENCE WILL BE PASSING OVER THE CWA.
SATURDAY NIGHT THROUGH TUESDAY...DID NOT MAKE MANY CHANGES PAST THIS
POINT. LAKE EFFECT SNOW LOOKS LIKELY FOR THE KEWEENAW AND FAR
NORTHEAST SATURDAY NIGHT THROUGH SUNDAY WITH WNW WINDS. A CORE OF
-17 TO -19C AIR GETS WRAPPED AROUND THE DEPARTING LOW AND CROSSES
LAKE SUPERIOR SATURDAY NIGHT. INVERSION HEIGHTS SHOULD STAY BETWEEN
4-5 KFT THROUGH MUCH OF SUNDAY UNDERNEATH SUBSIDENCE BEHIND THE
DEPARTING TROUGH. THOSE HEIGHTS THEN FALL UNDER 3 KFT AND DRY AIR
ADVECTS INTO THE REGION FROM THE SW SUNDAY NIGHT...THEREBY
DECREASING LES COVERAGE BY MONDAY. TEMPERATURES THEN REMAIN AROUND
SEASONAL NORMS TO START NEXT WEEK WITH MINIMAL PRECIP CHANCES.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z THURSDAY MORNING)
ISSUED AT 644 AM EST WED JAN 9 2013
COLD FRONT MOVING ACROSS UPPER MI WILL USHER IN STRONG/GUSTY W WINDS
TODAY. AT THE MORE EXPOSED KCMX LOCATION...WINDS WILL BE
STRONGEST...GUSTING TO AROUND 40KT FROM MID MORNING THRU EARLY AFTN.
AT KIWD/KSAW...WINDS SHOULD GUST TO AROUND 30KT. WINDS WILL QUICKLY
DIMINISH W TO E LATE AFTN/EVENING AS HIGH PRES RIDGE ARRIVES.
PER RADAR TRENDS/SFC OBS UPSTREAM...EXPECT A PERIOD OF IFR
CONDITIONS WITH -SHSN MID TO LATE MORNING AT KCMX. COULD SEE BRIEF
LIFR CONDITIONS. -SHSN SHOULD BE SHORT LIVED AS DRIER AIR ARRIVES
THIS AFTN. MVFR CIGS WILL PROBABLY PREVAIL AT KCMX DURING THE
AFTN...THEN SCATTER OUT TONIGHT AS WINDS BACK SRLY WITH PASSAGE OF
SFC HIGH PRES RIDGE. MAY SEE A PERIOD OF MVFR CIGS AT KIWD MID
MORNING THRU EARLY AFTN. AT KSAW...EXPECT DOWNSLOPING WESTERLY WINDS
TO RESULT IN VFR CONDITIONS THRU THE PERIOD.
&&
.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 526 AM EST WED JAN 9 2013
IN THE WAKE OF COLD FRONT PASSING ACROSS LAKE SUPERIOR THIS
MORNING...EXPECT W GALES OF 35-45KT TODAY. HIGH OBS PLATFORMS MAY
HAVE A COUPLE OF HRS OF GUSTS TO STORM FORCE JUST AHEAD OF 5MB/3HR
PRES RISES THAT WILL SHIFT ACROSS THE AREA TODAY. WINDS WILL QUICKLY
DIMINISH TO UNDER 20KT W TO E TONIGHT AS SFC HIGH PRES RIDGE MOVES
ACROSS LAKE SUPERIOR. INCREASING SOUTHERLY WINDS TO 20 TO 30 KNOTS
AHEAD OF AN APPROACHING LOW PRESSURE IN THE MID-MISSISSIPPI VALLEY
WILL AFFECT MAINLY THE EAST HALF OF LAKE SUPERIOR THURSDAY AND
THURSDAY NIGHT. LIGHT SOUTHERLY WINDS WILL THEN TAKE HOLD FRIDAY
BEFORE A COLD FRONT SWEEPS ACROSS THE LAKE FROM WEST TO EAST ON
SATURDAY. WESTERLY WINDS OF 25 TO 30 KNOTS WILL DEVELOP BY SATURDAY
AFTERNOON AND CONTINUE INTO EARLY SATURDAY EVENING. A FEW GALES TO 35
KNOTS WILL BE POSSIBLE ACROSS THE EAST HALF OF THE LAKE LATE SATURDAY
AFTERNOON. THE PATTERN BECOMES QUITE BENIGN BY SUNDAY...WITH MAINLY
WESTERLY WINDS UNDER 20 KNOTS THROUGH THE REMAINDER OF THE PERIOD.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
WIND ADVISORY UNTIL 5 PM EST THIS AFTERNOON FOR MIZ001-003.
LAKE SUPERIOR...
GALE WARNING UNTIL 10 PM EST THIS EVENING FOR LSZ249>251-266-267.
GALE WARNING UNTIL 7 PM EST THIS EVENING FOR LSZ243>248-264-265.
GALE WARNING UNTIL 4 PM EST /3 PM CST/ THIS AFTERNOON FOR LSZ162-
240>242-263.
LAKE MICHIGAN...
GALE WARNING UNTIL 4 PM EST THIS AFTERNOON FOR LMZ248-250.
GALE WARNING UNTIL 1 PM EST THIS AFTERNOON FOR LMZ221.
&&
$$
SHORT TERM...ROLFSON
LONG TERM...TK
AVIATION...ROLFSON
MARINE...ROLFSON/TK
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
529 AM EST WED JAN 9 2013
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 526 AM EST WED JAN 9 2013
WATER VAPOR IMAGERY AND RUC ANALYSIS SHOW A CONTINUED PROGRESSIVE
NRN STREAM ACROSS THE NRN CONUS/SRN CANADA. SHORTWAVE TROF IS
CURRENTLY MOVING OVER THE WRN GREAT LAKES. AT THE SFC...ASSOCIATED
LOW PRES IS OVER NRN ONTARIO. DESPITE RATHER VIGOROUS LOOK OF
SHORTWAVE...VERY LITTLE PCPN HAS OCCURRED OVER THE FCST AREA
OVERNIGHT. SOME PCPN PROBABLY OCCURRED OVER LAKE SUPERIOR PER RADAR
IMAGERY. OVER UPPER MI...NARROW BAND OF PCPN APPEARED TO DEVELOP
OVER THE ERN FCST AREA BTWN 07-09Z...BUT ONLY OB TO REPORT ANY PCPN
WAS AT KERY AND THAT WAS -RA.
FOCUS TODAY SHIFTS TO WINDS AND -SHSN CHANCES IN THE WAKE OF
SHORTWAVE. WEST WINDS WILL BE INCREASING ACROSS THE KEWEENAW OVER
THE NEXT SEVERAL HRS AS CAA INCREASES INSTABILITY/BUILDS MIXING
DEPTH TOWARD THE 45-50KT LOW-LEVEL WIND MAX AT 2-4KFT. COMBINED WITH
IDEAL WNW WIND DIRECTION FOR STRONG WINDS MAKES WIND ADVY ON THE
KEWEENAW AN OBVIOUS CALL. EXPECT STRONGEST WINDS TO OCCUR MID
MORNING INTO EARLY AFTN JUST AHEAD OF APPROACHING AREA OF 5MB/3HR
PRES RISES WHICH IS NOW OVER NE ND/FAR NW MN. GUSTS OF 45-50MPH
APPEAR LIKELY DURING THAT TIME. FARTHER S...WINDS ALONG THE SHORE
TOWARD ONTONAGON/SILVER CITY WILL BE CLOSE TO 45MPH. TO THE E...
SHORELINE LOCATIONS FROM PICTURED ROCKS EASTWARD WILL ALSO SEE GUSTS
TO AROUND 45 MPH. W WINDS SHOULD KEEP THESE HIGHER GUSTS CONFINED
MOSTLY TO THE BEACHES/SHORELINE. ELSEWHERE...IT WILL BE A BREEZY DAY
WITH WIND GUSTS GENERALLY IN THE 25 TO 35 MPH RANGE.
AS FOR PCPN...850MB TEMPS FALLING BRIEFLY TO AROUND -10C WILL BE
MARGINAL FOR LES OFF LAKE SUPERIOR. HOWEVER...SINCE THERE IS A SMALL
AREA OF -SN MOVING ACROSS NRN MN ATTM...EXPECT SOME -SHSN ON THE
KEWEENAW FOR A PORTION OF THE MORNING INTO EARLY AFTN...AND OVER THE
FAR NE FCST AREA DURING THE AFTN. A COUPLE OF OBS IN NRN MN HAVE
DROPPED TO AROUND 1SM...SO THERE CERTAINLY COULD BE A BRIEF PERIOD
OF HEAVIER SHSN. WILL BE SOMETHING TO MONITOR. RIGHT NOW...IT
APPEARS SNOW ACCUMULATIONS WILL BE UNDER AN INCH.
ALTHOUGH THERE WILL BE A TREND TOWARD CLEARING SKIES AWAY FROM THE
KEWEENAW AND FAR NE FCST AREA...CAA THRU MID DAY WILL LIMIT TEMP
RISE. MAX TEMPS SHOULDN`T BE TOO MUCH HIGHER THAN CURRENT READINGS.
30S WILL BE THE RULE.
SFC HIGH PRES RIDGE QUICKLY SHIFTS ACROSS UPPER MI TONIGHT. WITH
SKIES TRENDING TOWARD MAINLY CLEAR...THERE WILL BE A WINDOW FOR
TEMPS TO FALL SHARPLY UNDER A BRIEF PERIOD OF LIGHT/CALM WIND BEFORE
RETURN FLOW DEVELOPS. INDICATED MINS AS LOW AS THE LOW TEENS IN SOME
OF THE TRADITIONAL COLD SPOTS...BUT WOULDN`T BE SURPRISED TO SEE A
FEW SPOTS FALL INTO THE SINGLE DIGITS.
.LONG TERM...(THURSDAY THROUGH TUESDAY)
ISSUED AT 526 AM EST WED JAN 9 2013
A CONTINUED ACTIVE PATTERN WILL BE THE RULE THROUGH THE WEEKEND AS
MULTIPLE TROUGHS ARE PROGGED TO CROSS THE UPPER GREAT
LAKES...BRINGING WELL ABOVE NORMAL TEMPERATURES AND APPRECIABLE RAIN
FOR THE EAST HALF OF THE CWA.
THURSDAY AND THURSDAY NIGHT...THE UPPER GREAT LAKES AND MIDWEST WILL
BE UNDER THE INFLUENCE OF A PRONOUNCED MID-LEVEL TROUGH. THE LAYER
SHOULD BE FAIRLY DRY AND ALLOW FOR ABUNDANT SUNSHINE ACROSS THE CWA.
MEANWHILE...SOUTHERLY RETURN FLOW AHEAD OF AN APPROACHING
MID-LEVEL/SFC LOW OVER THE MID-MS VALLEY WILL BRING INCREASING WINDS
AND THIN...HIGH CIRRUS CLOUDS IN THE AFTERNOON. EXPECTATION IS THAT
MOSTLY SUNNY SKIES AND THE LOWER ALBEDO OF THE DENSE UPPER MI
FORESTS WILL RESULT IN TEMPS WELL-ABOVE NORMAL...AND EVEN SLIGHTLY
ABOVE CURRENT GUIDANCE. KEPT FORECAST VERY SIMILAR TO PREVIOUS
SHIFT...WITH UPPER 30S ACROSS MUCH OF THE INTERIOR AND LOW 40S FOR
DOWNSLOPE LOCATIONS ALONG LAKE SUPERIOR. SOME LOCATIONS WILL
APPROACH RECORD HIGHS IF DOWNSLOPE INFLUENCE IS STRONGER THAN
ANTICIPATED.
NOW ONTO THE SYSTEM TAKING AIM ON THE AREA THURSDAY NIGHT. A COMPACT
MID-LEVEL CUTOFF LOW NEAR THE GREAT BEND OF TEXAS IS BEGINNING ITS
TURN NORTHEASTWARD AND IS SET TO REACH THE MID-MS VALLEY BY LATE
THURSDAY NIGHT. MODEL AGREEMENT ON THIS SYSTEM HAS BECOME VERY GOOD
WITH THE EXCEPTION OF THE GFS...WHICH HAS BEEN TRENDING SLOWER. WILL
STICK WITH THE MORE CONSISTENT ECMWF/GEM SOLUTION.
THOUGH THE MAIN MID-LEVEL FORCING WITH THE SHORTWAVE WILL PASS JUST
TO THE SOUTHEAST OF THE CWA...DECENT ISENTROPIC LIFT ON THE 295-305K
SURFACES AND CONSIDERABLE LOW-LEVEL MOISTURE TRANSPORT ON THE NOSE
OF A 60KT H8 JET WILL SUPPORT MODERATE RAIN OVER THE EAST HALF OF
THE CWA. MOISTURE CONTENT OF THE COLUMN WILL BE AN IMPRESSIVE
1.1"/450 PERCENT OF NORMAL. GIVEN THE SET-UP AND HIGH WATER CONTENT
FOR JANUARY...HAVE CONTINUED THE TREND OF BUMPING UP POPS TO
WIDESPREAD RAIN ACROSS THE EASTERN TWO-THIRDS OF THE CWA BEGINNING
LATE THURSDAY EVENING. HELD OFF POPS FOR ALL BUT THE SOUTH-CENTRAL
CWA UNTIL THIS TIME. STORM TOTAL QPF OF A HALF INCH OR MORE FOR THE
EAST HALF SEEMS REASONABLE ATTM.
AS FOR PRECIP TYPE...TEMPERATURES ACROSS THE INTERIOR WEST AND
CENTRAL MAY FALL BELOW FREEZING IN THE EVENING BEFORE THICKER CLOUDS
AND WAA TAKE CONTROL AND WARM TEMPS BACK ABOVE FREEZING. INITIAL
RAIN WILL BE FALLING INTO QUITE A DRY LAYER...WITH SFC WET-BULB
TEMPS JUST UNDER FREEZING. HOWEVER...GIVEN WARM HIGHS AND
CONSIDERABLE SUNSHINE THURSDAY...A NARROW WINDOW OF BELOW FREEING
TEMPS...AND WARM RAIN FROM A 6 TO 8C WARM LAYER ABOVE THE SFC...ONLY
PUT IN A SLIGHT CHANCE OF FREEZING RAIN MAINLY INTERIOR CENTRAL. NOT
REALLY EXPECTING ANY ICING...BUT DID WANT TO PUT A SMALL MENTION IN
THERE.
FRIDAY THROUGH FRIDAY NIGHT...PRECIP WILL CONTINUE ACROSS THE EAST
HALF FRIDAY MORNING AS THE INFLUX OF MOISTURE CONTINUES OVER THE
AREA. A SECONDARY DEEP TROUGH MOVING INTO THE ROCKIES FRIDAY
AFTERNOON WILL BEGIN TO LIFT NORTHEASTWARD BY FRIDAY EVENING. IN
COMBINATION WITH THE LEFT EXIT OF A 140KT UPPER JET OVER THE
UPPER-MS VALLEY...A SFC LOW WILL QUICKLY FORM OVER MN FRIDAY NIGHT.
THERE SHOULD BE A LAPSE IN PRECIP FOR ALL BUT THE WESTERN CWA FRIDAY
NIGHT AS PLENTY OF DRY AIR IS DRAWN INTO THE REGION AHEAD OF THE
TROUGH/SFC LOW. SOME DRIZZLE IS POSSIBLE WITHIN A THICK LOW-LEVEL
STRATUS DECK WHERE RAIN SHOWERS MAY NOT BE AS PREVALENT CENTRAL AND
EAST. ALSO HAVE AREAS OF FOG IN THE FORECAST GIVEN RELATIVELY
WARM/MOIST AIR FLOWING OVER MELTING SNOW.
SATURDAY...AS THE SURFACE LOW TRACKS OVER LAKE SUPERIOR LATE FRIDAY
NIGHT INTO SATURDAY...IT WILL DRAW DOWN COLDER AIR FROM CANADA AND
SWEEP A COLD FRONT ACROSS THE CWA. HIGHS WILL LIKELY BE EARLY IN THE
DAY AS TEMPERATURES WILL QUICKLY FALL AT MOST LOCATIONS BY THE
AFTERNOON. EXPECT ANY RAIN SHOWERS TO TRANSITION TO SNOW SHOWERS
FROM WEST TO EAST THROUGHOUT THE DAY. ONLY MINOR ACCUMULATIONS ARE
EXPECTED AS MID/UPPER LEVEL SUPPORT WILL BE NORTH OF THE CWA AND
DECENT H5 Q-VECTOR DIVERGENCE WILL BE PASSING OVER THE CWA.
SATURDAY NIGHT THROUGH TUESDAY...DID NOT MAKE MANY CHANGES PAST THIS
POINT. LAKE EFFECT SNOW LOOKS LIKELY FOR THE KEWEENAW AND FAR
NORTHEAST SATURDAY NIGHT THROUGH SUNDAY WITH WNW WINDS. A CORE OF
-17 TO -19C AIR GETS WRAPPED AROUND THE DEPARTING LOW AND CROSSES
LAKE SUPERIOR SATURDAY NIGHT. INVERSION HEIGHTS SHOULD STAY BETWEEN
4-5 KFT THROUGH MUCH OF SUNDAY UNDERNEATH SUBSIDENCE BEHIND THE
DEPARTING TROUGH. THOSE HEIGHTS THEN FALL UNDER 3 KFT AND DRY AIR
ADVECTS INTO THE REGION FROM THE SW SUNDAY NIGHT...THEREBY
DECREASING LES COVERAGE BY MONDAY. TEMPERATURES THEN REMAIN AROUND
SEASONAL NORMS TO START NEXT WEEK WITH MINIMAL PRECIP CHANCES.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z THURSDAY MORNING)
ISSUED AT 526 AM EST WED JAN 9 2013
SOUTHERLY WINDS AHEAD OF A FRONTAL SYSTEM HAS BROUGHT LOW CLOUDS
ACROSS UPPER MICHIGAN THIS EVENING. EXPECT THE MVFR CLOUDS TO
PERSIST UNTIL MIDDAY WHEN DRIER AIR WILL MOVE IN FROM THE WEST.
EXPECT GUSTY WESTERLY WINDS LATE IN THE NIGHT INTO TODAY BEHIND THE
FRONT. DECENT COLD AIR MOVING OVER LAKE SUPERIOR WILL SUPPORT GUSTS
TO 40KTS AT KCMX AROUND DAYBREAK AND CONTINUING FOR MUCH OF THE
MORNING. AT THE OTHER TWO SITES...WINDS WILL BE GUSTY AND IN THE
20-30KT RANGE. WINDS WILL DIMINISH TOWARD EVENING AS A RIDGE BUILDS
FROM THE UPPER MISSISSIPPI VALLEY INTO THE WESTERN GREAT LAKES.
&&
.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 526 AM EST WED JAN 9 2013
IN THE WAKE OF COLD FRONT PASSING ACROSS LAKE SUPERIOR THIS
MORNING...EXPECT W GALES OF 35-45KT TODAY. HIGH OBS PLATFORMS MAY
HAVE A COUPLE OF HRS OF GUSTS TO STORM FORCE JUST AHEAD OF 5MB/3HR
PRES RISES THAT WILL SHIFT ACROSS THE AREA TODAY. WINDS WILL QUICKLY
DIMINISH TO UNDER 20KT W TO E TONIGHT AS SFC HIGH PRES RIDGE MOVES
ACROSS LAKE SUPERIOR. INCREASING SOUTHERLY WINDS TO 20 TO 30 KNOTS
AHEAD OF AN APPROACHING LOW PRESSURE IN THE MID-MISSISSIPPI VALLEY
WILL AFFECT MAINLY THE EAST HALF OF LAKE SUPERIOR THURSDAY AND
THURSDAY NIGHT. LIGHT SOUTHERLY WINDS WILL THEN TAKE HOLD FRIDAY
BEFORE A COLD FRONT SWEEPS ACROSS THE LAKE FROM WEST TO EAST ON
SATURDAY. WESTERLY WINDS OF 25 TO 30 KNOTS WILL DEVELOP BY SATURDAY
AFTERNOON AND CONTINUE INTO EARLY SATURDAY EVENING. A FEW GALES TO 35
KNOTS WILL BE POSSIBLE ACROSS THE EAST HALF OF THE LAKE LATE SATURDAY
AFTERNOON. THE PATTERN BECOMES QUITE BENIGN BY SUNDAY...WITH MAINLY
WESTERLY WINDS UNDER 20 KNOTS THROUGH THE REMAINDER OF THE PERIOD. &&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
WIND ADVISORY UNTIL 5 PM EST THIS AFTERNOON FOR MIZ001-003.
LAKE SUPERIOR...
GALE WARNING UNTIL 10 PM EST THIS EVENING FOR LSZ249>251-266-267.
GALE WARNING UNTIL 7 PM EST THIS EVENING FOR LSZ243>248-264-265.
GALE WARNING UNTIL 4 PM EST /3 PM CST/ THIS AFTERNOON FOR LSZ162-
240>242-263.
LAKE MICHIGAN...
GALE WARNING UNTIL 4 PM EST THIS AFTERNOON FOR LMZ248-250.
GALE WARNING UNTIL 1 PM EST THIS AFTERNOON FOR LMZ221.
&&
$$
SHORT TERM...ROLFSON
LONG TERM...TK
AVIATION...JLB
MARINE...ROLFSON/TK
AREA FORECAST DISCUSSION
NWS TWIN CITIES/CHANHASSEN MN
1138 AM CST WED JAN 9 2013
.UPDATE...FOR 18Z AVIATION DISCUSSION BELOW
&&
.DISCUSSION.../ISSUED 437 AM CST WED JAN 9 2013/
MAIN FORECAST CONCERN FOR THIS PERIOD WAS IN THE THURSDAY THROUGH
SATURDAY TIME FRAME AS AN UNCHARACTERISTICALLY WARM AND MOIST
SYSTEM FOR JANUARY STANDARDS IMPACTS THE AREA...WITH WHAT LOOKS
TO BE PRIMARILY RAIN THURSDAY THROUGH FRIDAY...WITH A TRANSITION
BACK TO SNOW FRIDAY EVENING.
VERY MILD CONDITIONS TO START THE DAY...WITH MANY AREAS STILL IN
THE 30S AT 3AM AS THE AREA SITS OUT AHEAD OF PACIFIC COLD FRONT
CURRENTLY MOVING ACROSS THE DAKOTAS. CURRENT HIGHS FOR TODAY ONLY 5
TO 10 DEGS HIGHER THAN CURRENT TEMPS...SO COULD END UP BEING A BIT
WARMER THAN CURRENTLY FORECAST...ESPECIALLY EAST OF THE BUFFALO
RIDGE IN SW MN...WHERE TEMPS ARE A DEGREE OR TWO ON EITHER SIDE
OF 35 AT THE MOMENT. ALSO GETTING SOME STRONG WINDS IN THE WRN CWA
THIS MORNING...WITH SPEEDS UP NEAR ADVY LEVELS...WITH SOME
SUSTAINED WINDS IN THE AXN/MOX AREA NEAR 30 MPH...WITH GUSTS
APPROACHING 40. FORTUNATELY...NOT EXPECTING THINGS TO GET ANY
WORSE THAN WHAT WE HAVE ALREADY SEEN SINCE MAIN PUSH OF PRESSURE
RISES WILL BE GOING NORTH OF HERE...ALONG WITH A STRONG INVERSION
MAKING IT DIFFICULT TO MIX MUCH WIND TO THE GROUND. THIS SECOND
PART IS FORTUNATE...AS RAP SHOWS 1K FT WINDS UP AT 40 KTS...BUT
THE INVERSION WILL KEEP THOSE UP THERE...MEANING A WIND ADVY IS
UNNECESSARY FOR TODAY.
THE WEATHER LOOKS QUIET TODAY THROUGH TONIGHT...BUT STILL LOOKS
TO TURN SOUTH IN A HURRY THURSDAY AFTERNOON. CUT OFF LOW WITH A
WALL OF WATER OVER TX THIS MORNING WILL SLOWLY DRIFT NORTH TODAY
AS A SHARP THROUGH MOVES ONSHORE OUT WEST. AS THE MAIN TROUGH
WORKS ACROSS THE ROCKIES THURSDAY...IT WILL PICK UP THE CLOSED LOW
A QUICKLY SEND IT AND ITS RAIN NORTH TOWARD THE GREAT LAKES. AS
WITH PREVIOUS FORECAST...FAVORED A GEM/ECMWF BLEND FOR TIMING
PRECIP IN THURSDAY/THURSDAY NIGHT AS THIS IS A GOOD COMPROMISE
BETWEEN THE NAM...WHICH IS ABOUT 6 HOURS FASTER AND THE GFS WHICH
IS 6 HOURS SLOWER THAN THE GEM/ECMWF. HOWEVER...WORRIED NAM MAY BE
RIGHT WITH THE FASTER TIMING. THIS IS BECAUSE A QUICK LOOK AT H85
MOISTURE TRANSPORT ON THE ECMWF SHOWS THAT IT AGREES MUCH MORE
WITH THE TIMING INDICATED BY THE NAM QPF THAN ITS OWN...SO WOULD
NOT BE SURPRISED IF WE NEED TO START SPEEDING UP THE SPREAD OF
POPS NORTH THURSDAY AFTERNOON.
BIG ISSUE WITH PRECIP THURSDAY NIGHT THROUGH FRIDAY IS ALL MODELS
ARE SHOWING THE MPX CWA GETTING DRY SLOTTED...WITH MOISTURE
REMAINING RATHER SHALLOW AFTER THE INITIAL PUSH OF PRECIP THURSDAY
AFTERNOON. DID FAVOR QPF THU/THU NIGHT TOWARD THE HIGHER HPC
NUMBERS AS BOTH THE NAM AND GFS SHOW PWATS WITH THIS INITIAL SURGE
OF PRECIP INCREASE TO AND EVEN EXCEEDING 1 INCH. THIS IS A GOOD
400-500 PERCENT OF NORMAL. THE HIGHEST PWAT EVER OBSERVED AT
MPX/STC IN JANUARY IS 0.92...SO WHAT WE WILL BE SEEING THURSDAY
WILL BE QUITE RARE INDEED. BASED ON THE HIGH PWAT...LIKE THE
HIGHER HPC NUMBERS...THOUGH HEAVIEST RAIN WILL BE DIRECTED MORE
TOWARD GREEN BAY...WHERE BEST LLJ AND MOISTURE TRANSPORT WILL BE
DIRECTED. DRY SLOTTING THURSDAY NIGHT THROUGH FRIDAY RESULTS IN
SOUNDINGS LACKING ANY ICE CRYSTALS...WITH DRIZZLE LOOKING TO BE THE
PRIMARY PRECIP SEEN IN THIS PERIOD.
AS FOR P-TYPE...FAVORED TEMPERATURE FORECAST THU-FRI TOWARD THE
GEM/ECMWF AS WELL...WHICH RESULTS IN A MUCH WARMER SCENARIO. BY
THE TIME PRECIP GETS HERE THURSDAY AFTERNOON...CURRENTLY HAVE THE
ENTIRE CWA ABV FREEZING...SO KEPT PRECIP MENTION THURSDAY AS ONLY
RAIN. FOR THURSDAY NIGHT...MAY BE QUESTIONABLE IF LOWS ANYWHERE IN
THE MPX CWA DROP BELOW FREEZING...WHICH MEANS RAIN WILL LIKELY BE
THE PRIMARY P-TYPE RIGHT THROUGH THURSDAY NIGHT. ON
FRIDAY...MODELS BEGINNING TO REALLY TIGHTEN UP BAROCLINIC ZONE
THAT WILL BE JUST WEST/NW OF THE MPX AREA...WITH WINDS BACKING TO
THE SE. THIS SHOULD ALLOW 40 DEG TEMPERATURES TO SNEAK INTO ERN
AREAS FRIDAY. THIS FRONT DOES NOT LOOK TO START WORKING ACROSS
THE MPX CWA UNTIL FRIDAY NIGHT BASED ON AN ECMWF/GFS/NAM BLEND AS
A RAPIDLY DEEPENING SFC LOW MOVES UP FROM NEAR SIOUX FALLS UP TO
THE ARROWHEAD. NO OTHER WAY TO EXPLAIN THE CAA BEHIND THIS FRONT
FRIDAY NIGHT OTHER THAN AS INTENSE...WITH WIND ADVY STRENGTH WINDS
LOOKING LIKELY AND TEMPERATURES LIKELY DROPPING 20 DEGREES OR MORE
WITHIN AN HOUR OR TWO. THIS WILL QUICKLY TURN ANY PRECIP OVER TO
SNOW...THOUGH TRACK OF THE LOW WILL KEEP PRIMARY BAND OF SNOW
ACROSS NW MN.
LOOKING AT POTENTIAL HEADLINES...THERE WILL BE THE POSSIBILITY FOR
TWO WITH THIS SYSTEM...A WINTER WEATHER AND WIND ADVY. AT THE
MOMENT...THE MOST LIKELY PLACE THAT MAY NEED A WINTER WX ADVY IS
THE FAR NW CWA. THIS IS WHERE THE HIGHEST POTENTIAL FOR SEEING
FZRA WILL BE THURSDAY NIGHT...FOLLOWED BY THE POTENTIAL FOR A FEW
INCHES OF SNOW FRIDAY NIGHT INTO SATURDAY DEPENDING ON HOW FAR SE
THE DEFORMATION PRECIP BAND SETS UP. AS FOR THE WIND ADVY...FRIDAY
NIGHT IS LOOKING QUITE BREEZY...ESPECIALLY ON THE ECMWF...WHICH
DEVELOPS SUSTAINED WINDS IN WRN MN IN EXCESS OF 30 MPH...WITH
GUSTS OVER 40 MPH IN RESPONSE TO IT SENDING A 990 LOW OVER TO THE
WEST END OF LAKE SUPERIOR AS A 1030 MB HIGH MOVES INTO THE BLACK
HILLS.
AS FOR THE REST OF THE FORECAST...IT IS LOOKING COOLER...ESPECIALLY
SATURDAY THROUGH MONDAY...WHEN BELOW ZERO LOWS WILL RETURN WITH
HIGHS IN THE SINGLE DIGITS AND TEENS...THOUGH WE COULD GET WARMER
THAN THAT AS WARM TEMPS THURSDAY/FRIDAY WILL LIKELY PUNCH A LOT OF
HOLES IN THE SNOWPACK OUTSIDE OF THE NW CWA...WHICH WILL LIKELY
GET SOME SNOW FRIDAY NIGHT. BY THE MIDDLE OF THE WEEK...BOTH THE
GFS/ECMWF SHOW TEMPERATURES MODERATING OUT AHEAD OF CLIPPER COMING
DOWN TUESDAY NIGHT/WEDNESDAY. ALSO INTERESTING IS THAT AS NEXT
WEEK GROWS CLOSER...THE GFS/ECMWF CONTINUE TO BACK OFF ON THE
EXTENT TO WHICH THE ARCTIC AIR MAKES IN INTO THE US...WITH EACH
NEW RUN SEEMING TO KEEP IT FURTHER AND FURTHER NORTH...SO THAT WILL
BE SOMETHING TO WATCH. AS FOR WEATHER...AFTER THURSDAY NIGHT
THROUGH SATURDAY IT LOOKS DRY.
&&
.AVIATION.../18Z TAF ISSUANCE/
VFR CONDITIONS WITH CLEAR SKIES WILL PREVAIL THROUGH THURSDAY
MORNING...ALTHOUGH WIND SHEAR IS EXPECTED TO IMPACT SEVERAL SITES
OVER WEST CENTRAL AND CENTRAL MN TONIGHT THROUGH THURSDAY MORNING.
IN THE MEANTIME...SURFACE WINDS WILL CONTINUE SUBSIDING BELOW 10
KTS FROM WEST TO EAST AND BACKING THIS AFTERNOON AS RIDGING BUILDS
INTO THE AREA. AROUND/AFTER 06Z TONIGHT...A LOW LEVEL JET NOSES
INTO WESTERN/CENTRAL MN...WHEN THE NAM INDICATES 0-1KM AGL SHEAR
MAGNITUDE AROUND 50 KTS DEVELOPING. HAVE INCLUDED LLVL WIND SHEAR
IN THE KAXN/KRWF/KSTC TAFS AROUND 1500 FT TONIGHT UNTIL LATE
THURSDAY MORNING. ATTENTION THEN TURNS TO INCREASING CLOUD COVER AND
PRECIP CHANCES WITH THE NEXT SYSTEM. SHOULD SEE MID/HIGH CLOUDS ON
THE INCREASE AFTER 18Z THURSDAY...WITH SUB-VFR CONDITIONS EXPECTED
TO HOLD OFF UNTIL 23Z. SHOULD THEN SEE RAPID DETERIORATION IN
CONDITIONS AFTER 00Z FRIDAY IN CONJUNCTION WITH THE ONSET OF -RA
AND DZ.
KMSP...
HIGH CONFIDENCE IN VFR CONDITIONS THROUGH 21Z THURSDAY...AND THEN
DETERIORATING CONDITIONS TO IFR CIGS/VSBYS EXPECTED AROUND/AFTER
23Z THURSDAY AS LIGHT PRECIP BEGINS. WINDS AROUND 270-290 DEGREES
TO START THE PERIOD...BACKING TO AROUND 190-200 DEGREES BY
00Z...THEN FURTHER BACKING TO AROUND 150 DEGREES FROM 03Z THROUGH
THE REMAINDER OF THE PERIOD. SPEEDS INITIALLY AROUND 12-15
KTS...THEN RANGING BETWEEN 6 AND 12 KTS AFTER 21Z. WHILE THE MAIN
CORE OF THE LOW LEVEL JET IS EXPECTED WEST/NORTHWEST OF
KMSP...COULD SEE 1500-2000FT WINDS OF 45-50 KTS AFTER 06Z.
/OUTLOOK FOR KMSP/
THU NIGHT...IFR CIGS/VSBYS WITH RAIN EARLY...THEN LIFR CONDITIONS
POSSIBLE IN DZ AND FG. WINDS SE AT 5-10 KTS.
FRI...IFR WITH DZ AND FG. LIFR POSSIBLE. WINDS SE AT 5-10 KTS.
SAT...MVFR WITH -SHSN POSSIBLE. COLD FRONT PASSAGE EARLY. WINDS W
AT 20G30KTS.
&&
.MPX WATCHES/WARNINGS/ADVISORIES...
MN...NONE.
WI...NONE.
&&
$$
BORGHOFF/LS
AREA FORECAST DISCUSSION...UPDATED
NWS TWIN CITIES/CHANHASSEN MN
614 AM CST WED JAN 9 2013
.UPDATE...UPDATED FOR AVIATION DISCUSSION BELOW.
&&
.PREV DISCUSSION.../ISSUED 437 AM CST WED JAN 9 2013/
MAIN FORECAST CONCERN FOR THIS PERIOD WAS IN THE THURSDAY THROUGH
SATURDAY TIME FRAME AS AN UNCHARACTERISTICALLY WARM AND MOIST
SYSTEM FOR JANUARY STANDARDS IMPACTS THE AREA...WITH WHAT LOOKS
TO BE PRIMARILY RAIN THURSDAY THROUGH FRIDAY...WITH A TRANSITION
BACK TO SNOW FRIDAY EVENING.
VERY MILD CONDITIONS TO START THE DAY...WITH MANY AREAS STILL IN
THE 30S AT 3AM AS THE AREA SITS OUT AHEAD OF PACIFIC COLD FRONT
CURRENTLY MOVING ACROSS THE DAKOTAS. CURRENT HIGHS FOR TODAY ONLY 5
TO 10 DEGS HIGHER THAN CURRENT TEMPS...SO COULD END UP BEING A BIT
WARMER THAN CURRENTLY FORECAST...ESPECIALLY EAST OF THE BUFFALO
RIDGE IN SW MN...WHERE TEMPS ARE A DEGREE OR TWO ON EITHER SIDE
OF 35 AT THE MOMENT. ALSO GETTING SOME STRONG WINDS IN THE WRN CWA
THIS MORNING...WITH SPEEDS UP NEAR ADVY LEVELS...WITH SOME
SUSTAINED WINDS IN THE AXN/MOX AREA NEAR 30 MPH...WITH GUSTS
APPROACHING 40. FORTUNATELY...NOT EXPECTING THINGS TO GET ANY
WORSE THAN WHAT WE HAVE ALREADY SEEN SINCE MAIN PUSH OF PRESSURE
RISES WILL BE GOING NORTH OF HERE...ALONG WITH A STRONG INVERSION
MAKING IT DIFFICULT TO MIX MUCH WIND TO THE GROUND. THIS SECOND
PART IS FORTUNATE...AS RAP SHOWS 1K FT WINDS UP AT 40 KTS...BUT
THE INVERSION WILL KEEP THOSE UP THERE...MEANING A WIND ADVY IS
UNNECESSARY FOR TODAY.
THE WEATHER LOOKS QUIET TODAY THROUGH TONIGHT...BUT STILL LOOKS
TO TURN SOUTH IN A HURRY THURSDAY AFTERNOON. CUT OFF LOW WITH A
WALL OF WATER OVER TX THIS MORNING WILL SLOWLY DRIFT NORTH TODAY
AS A SHARP THROUGH MOVES ONSHORE OUT WEST. AS THE MAIN TROUGH
WORKS ACROSS THE ROCKIES THURSDAY...IT WILL PICK UP THE CLOSED LOW
A QUICKLY SEND IT AND ITS RAIN NORTH TOWARD THE GREAT LAKES. AS
WITH PREVIOUS FORECAST...FAVORED A GEM/ECMWF BLEND FOR TIMING
PRECIP IN THURSDAY/THURSDAY NIGHT AS THIS IS A GOOD COMPROMISE
BETWEEN THE NAM...WHICH IS ABOUT 6 HOURS FASTER AND THE GFS WHICH
IS 6 HOURS SLOWER THAN THE GEM/ECMWF. HOWEVER...WORRIED NAM MAY BE
RIGHT WITH THE FASTER TIMING. THIS IS BECAUSE A QUICK LOOK AT H85
MOISTURE TRANSPORT ON THE ECMWF SHOWS THAT IT AGREES MUCH MORE
WITH THE TIMING INDICATED BY THE NAM QPF THAN ITS OWN...SO WOULD
NOT BE SURPRISED IF WE NEED TO START SPEEDING UP THE SPREAD OF
POPS NORTH THURSDAY AFTERNOON.
BIG ISSUE WITH PRECIP THURSDAY NIGHT THROUGH FRIDAY IS ALL MODELS
ARE SHOWING THE MPX CWA GETTING DRY SLOTTED...WITH MOISTURE
REMAINING RATHER SHALLOW AFTER THE INITIAL PUSH OF PRECIP THURSDAY
AFTERNOON. DID FAVOR QPF THU/THU NIGHT TOWARD THE HIGHER HPC
NUMBERS AS BOTH THE NAM AND GFS SHOW PWATS WITH THIS INITIAL SURGE
OF PRECIP INCREASE TO AND EVEN EXCEEDING 1 INCH. THIS IS A GOOD
400-500 PERCENT OF NORMAL. THE HIGHEST PWAT EVER OBSERVED AT
MPX/STC IN JANUARY IS 0.92...SO WHAT WE WILL BE SEEING THURSDAY
WILL BE QUITE RARE INDEED. BASED ON THE HIGH PWAT...LIKE THE
HIGHER HPC NUMBERS...THOUGH HEAVIEST RAIN WILL BE DIRECTED MORE
TOWARD GREEN BAY...WHERE BEST LLJ AND MOISTURE TRANSPORT WILL BE
DIRECTED. DRY SLOTTING THURSDAY NIGHT THROUGH FRIDAY RESULTS IN
SOUNDINGS LACKING ANY ICE CRYSTALS...WITH DRIZZLE LOOKING TO BE THE
PRIMARY PRECIP SEEN IN THIS PERIOD.
AS FOR P-TYPE...FAVORED TEMPERATURE FORECAST THU-FRI TOWARD THE
GEM/ECMWF AS WELL...WHICH RESULTS IN A MUCH WARMER SCENARIO. BY
THE TIME PRECIP GETS HERE THURSDAY AFTERNOON...CURRENTLY HAVE THE
ENTIRE CWA ABV FREEZING...SO KEPT PRECIP MENTION THURSDAY AS ONLY
RAIN. FOR THURSDAY NIGHT...MAY BE QUESTIONABLE IF LOWS ANYWHERE IN
THE MPX CWA DROP BELOW FREEZING...WHICH MEANS RAIN WILL LIKELY BE
THE PRIMARY P-TYPE RIGHT THROUGH THURSDAY NIGHT. ON
FRIDAY...MODELS BEGINNING TO REALLY TIGHTEN UP BAROCLINIC ZONE
THAT WILL BE JUST WEST/NW OF THE MPX AREA...WITH WINDS BACKING TO
THE SE. THIS SHOULD ALLOW 40 DEG TEMPERATURES TO SNEAK INTO ERN
AREAS FRIDAY. THIS FRONT DOES NOT LOOK TO START WORKING ACROSS
THE MPX CWA UNTIL FRIDAY NIGHT BASED ON AN ECMWF/GFS/NAM BLEND AS
A RAPIDLY DEEPENING SFC LOW MOVES UP FROM NEAR SIOUX FALLS UP TO
THE ARROWHEAD. NO OTHER WAY TO EXPLAIN THE CAA BEHIND THIS FRONT
FRIDAY NIGHT OTHER THAN AS INTENSE...WITH WIND ADVY STRENGTH WINDS
LOOKING LIKELY AND TEMPERATURES LIKELY DROPPING 20 DEGREES OR MORE
WITHIN AN HOUR OR TWO. THIS WILL QUICKLY TURN ANY PRECIP OVER TO
SNOW...THOUGH TRACK OF THE LOW WILL KEEP PRIMARY BAND OF SNOW
ACROSS NW MN.
LOOKING AT POTENTIAL HEADLINES...THERE WILL BE THE POSSIBILITY FOR
TWO WITH THIS SYSTEM...A WINTER WEATHER AND WIND ADVY. AT THE
MOMENT...THE MOST LIKELY PLACE THAT MAY NEED A WINTER WX ADVY IS
THE FAR NW CWA. THIS IS WHERE THE HIGHEST POTENTIAL FOR SEEING
FZRA WILL BE THURSDAY NIGHT...FOLLOWED BY THE POTENTIAL FOR A FEW
INCHES OF SNOW FRIDAY NIGHT INTO SATURDAY DEPENDING ON HOW FAR SE
THE DEFORMATION PRECIP BAND SETS UP. AS FOR THE WIND ADVY...FRIDAY
NIGHT IS LOOKING QUITE BREEZY...ESPECIALLY ON THE ECMWF...WHICH
DEVELOPS SUSTAINED WINDS IN WRN MN IN EXCESS OF 30 MPH...WITH
GUSTS OVER 40 MPH IN RESPONSE TO IT SENDING A 990 LOW OVER TO THE
WEST END OF LAKE SUPERIOR AS A 1030 MB HIGH MOVES INTO THE BLACK
HILLS.
AS FOR THE REST OF THE FORECAST...IT IS LOOKING COOLER...ESPECIALLY
SATURDAY THROUGH MONDAY...WHEN BELOW ZERO LOWS WILL RETURN WITH
HIGHS IN THE SINGLE DIGITS AND TEENS...THOUGH WE COULD GET WARMER
THAN THAT AS WARM TEMPS THURSDAY/FRIDAY WILL LIKELY PUNCH A LOT OF
HOLES IN THE SNOWPACK OUTSIDE OF THE NW CWA...WHICH WILL LIKELY
GET SOME SNOW FRIDAY NIGHT. BY THE MIDDLE OF THE WEEK...BOTH THE
GFS/ECMWF SHOW TEMPERATURES MODERATING OUT AHEAD OF CLIPPER COMING
DOWN TUESDAY NIGHT/WEDNESDAY. ALSO INTERESTING IS THAT AS NEXT
WEEK GROWS CLOSER...THE GFS/ECMWF CONTINUE TO BACK OFF ON THE
EXTENT TO WHICH THE ARCTIC AIR MAKES IN INTO THE US...WITH EACH
NEW RUN SEEMING TO KEEP IT FURTHER AND FURTHER NORTH...SO THAT WILL
BE SOMETHING TO WATCH. AS FOR WEATHER...AFTER THURSDAY NIGHT
THROUGH SATURDAY IT LOOKS DRY.
&&
.AVIATION.../12Z TAF ISSUANCE/
MAIN FORECAST CONCERN FOR THIS ISSUANCE IS WIND...WITH VFR
CONDITIONS EXPECTED FOR THE NEXT 24 TO 30 HOURS. GUSTY WEST WINDS
WILL SUBSIDE LATER THIS MORNING AND BACK SOUTHERLY BY EVENING. AS
A NEW STORM SYSTEM DEVELOPS TO THE WEST...WINDS WILL STRENGTHEN
AGAIN OVERNIGHT...ESPECIALLY ACROSS WRN MN WHERE SOME GUSTS MAY
EXCEED 25 KTS. IN ADDITION...A STRONG LOW LEVEL JET OF 50 TO 55
KTS IS EXPECTED TO DEVELOP AROUND 1000 FT AFTER 06Z WHICH HAS LED
TO THE INCLUSION OF WIND SHEAR MENTION AT AXN...RWF...AND STC.
KMSP...VFR CONDITIONS THROUGH 18Z THURSDAY WITH SKC. RAPIDLY
DETERIORATING CONDITIONS EXPECTED JUST AFTER THE CURRENT PERIOD
WITH TREMENDOUS AMOUNTS OF INCOMING MOISTURE. MVFR OR LOWER
CONDITIONS LIKELY BY LATE THURSDAY AFTERNOON. GUSTY WEST WINDS
WILL SUBSIDE LATER THIS MORNING AND BACK SOUTH BY EVENING. COULD
SEE WINDS APPROACH 50 KTS AT 1000FT LATE TONIGHT...BUT DECIDED
AGAINST INCLUDING WIND SHEAR WITH THIS ISSUANCE GIVEN MORE
UNCERTAINTY ACROSS ERN MN.
/OUTLOOK FOR KMSP/
THU NIGHT...IFR CIGS/VSBYS WITH RAIN EARLY...THEN LIFR CONDITIONS
POSSIBLE IN DZ AND FG. WINDS SE AT 5-10 KTS.
FRI...IFR WITH DZ AND FG. LIFR POSSIBLE. WINDS SE AT 5-10 KTS.
SAT...MVFR WITH -SHSN POSSIBLE. COLD FRONT PASSAGE EARLY. WINDS W
AT 20G30KTS.
&&
.MPX WATCHES/WARNINGS/ADVISORIES...
MN...NONE.
WI...NONE.
&&
$$
MPG/BORGHOFF
AREA FORECAST DISCUSSION
NWS TWIN CITIES/CHANHASSEN MN
437 AM CST WED JAN 9 2013
.DISCUSSION...
MAIN FORECAST CONCERN FOR THIS PERIOD WAS IN THE THURSDAY THROUGH
SATURDAY TIME FRAME AS AN UNCHARACTERISTICALLY WARM AND MOIST
SYSTEM FOR JANUARY STANDARDS IMPACTS THE AREA...WITH WHAT LOOKS
TO BE PRIMARILY RAIN THURSDAY THROUGH FRIDAY...WITH A TRANSITION
BACK TO SNOW FRIDAY EVENING.
VERY MILD CONDITIONS TO START THE DAY...WITH MANY AREAS STILL IN
THE 30S AT 3AM AS THE AREA SITS OUT AHEAD OF PACIFIC COLD FRONT
CURRENTLY MOVING ACROSS THE DAKOTAS. CURRENT HIGHS FOR TODAY ONLY 5
TO 10 DEGS HIGHER THAN CURRENT TEMPS...SO COULD END UP BEING A BIT
WARMER THAN CURRENTLY FORECAST...ESPECIALLY EAST OF THE BUFFALO
RIDGE IN SW MN...WHERE TEMPS ARE A DEGREE OR TWO ON EITHER SIDE
OF 35 AT THE MOMENT. ALSO GETTING SOME STRONG WINDS IN THE WRN CWA
THIS MORNING...WITH SPEEDS UP NEAR ADVY LEVELS...WITH SOME
SUSTAINED WINDS IN THE AXN/MOX AREA NEAR 30 MPH...WITH GUSTS
APPROACHING 40. FORTUNATELY...NOT EXPECTING THINGS TO GET ANY
WORSE THAN WHAT WE HAVE ALREADY SEEN SINCE MAIN PUSH OF PRESSURE
RISES WILL BE GOING NORTH OF HERE...ALONG WITH A STRONG INVERSION
MAKING IT DIFFICULT TO MIX MUCH WIND TO THE GROUND. THIS SECOND
PART IS FORTUNATE...AS RAP SHOWS 1K FT WINDS UP AT 40 KTS...BUT
THE INVERSION WILL KEEP THOSE UP THERE...MEANING A WIND ADVY IS
UNNECESSARY FOR TODAY.
THE WEATHER LOOKS QUIET TODAY THROUGH TONIGHT...BUT STILL LOOKS
TO TURN SOUTH IN A HURRY THURSDAY AFTERNOON. CUT OFF LOW WITH A
WALL OF WATER OVER TX THIS MORNING WILL SLOWLY DRIFT NORTH TODAY
AS A SHARP THROUGH MOVES ONSHORE OUT WEST. AS THE MAIN TROUGH
WORKS ACROSS THE ROCKIES THURSDAY...IT WILL PICK UP THE CLOSED LOW
A QUICKLY SEND IT AND ITS RAIN NORTH TOWARD THE GREAT LAKES. AS
WITH PREVIOUS FORECAST...FAVORED A GEM/ECMWF BLEND FOR TIMING
PRECIP IN THURSDAY/THURSDAY NIGHT AS THIS IS A GOOD COMPROMISE
BETWEEN THE NAM...WHICH IS ABOUT 6 HOURS FASTER AND THE GFS WHICH
IS 6 HOURS SLOWER THAN THE GEM/ECMWF. HOWEVER...WORRIED NAM MAY BE
RIGHT WITH THE FASTER TIMING. THIS IS BECAUSE A QUICK LOOK AT H85
MOISTURE TRANSPORT ON THE ECMWF SHOWS THAT IT AGREES MUCH MORE
WITH THE TIMING INDICATED BY THE NAM QPF THAN ITS OWN...SO WOULD
NOT BE SURPRISED IF WE NEED TO START SPEEDING UP THE SPREAD OF
POPS NORTH THURSDAY AFTERNOON.
BIG ISSUE WITH PRECIP THURSDAY NIGHT THROUGH FRIDAY IS ALL MODELS
ARE SHOWING THE MPX CWA GETTING DRY SLOTTED...WITH MOISTURE
REMAINING RATHER SHALLOW AFTER THE INITIAL PUSH OF PRECIP THURSDAY
AFTERNOON. DID FAVOR QPF THU/THU NIGHT TOWARD THE HIGHER HPC
NUMBERS AS BOTH THE NAM AND GFS SHOW PWATS WITH THIS INITIAL SURGE
OF PRECIP INCREASE TO AND EVEN EXCEEDING 1 INCH. THIS IS A GOOD
400-500 PERCENT OF NORMAL. THE HIGHEST PWAT EVER OBSERVED AT
MPX/STC IN JANUARY IS 0.92...SO WHAT WE WILL BE SEEING THURSDAY
WILL BE QUITE RARE INDEED. BASED ON THE HIGH PWAT...LIKE THE
HIGHER HPC NUMBERS...THOUGH HEAVIEST RAIN WILL BE DIRECTED MORE
TOWARD GREEN BAY...WHERE BEST LLJ AND MOISTURE TRANSPORT WILL BE
DIRECTED. DRY SLOTTING THURSDAY NIGHT THROUGH FRIDAY RESULTS IN
SOUNDINGS LACKING ANY ICE CRYSTALS...WITH DRIZZLE LOOKING TO BE THE
PRIMARY PRECIP SEEN IN THIS PERIOD.
AS FOR P-TYPE...FAVORED TEMPERATURE FORECAST THU-FRI TOWARD THE
GEM/ECMWF AS WELL...WHICH RESULTS IN A MUCH WARMER SCENARIO. BY
THE TIME PRECIP GETS HERE THURSDAY AFTERNOON...CURRENTLY HAVE THE
ENTIRE CWA ABV FREEZING...SO KEPT PRECIP MENTION THURSDAY AS ONLY
RAIN. FOR THURSDAY NIGHT...MAY BE QUESTIONABLE IF LOWS ANYWHERE IN
THE MPX CWA DROP BELOW FREEZING...WHICH MEANS RAIN WILL LIKELY BE
THE PRIMARY P-TYPE RIGHT THROUGH THURSDAY NIGHT. ON
FRIDAY...MODELS BEGINNING TO REALLY TIGHTEN UP BAROCLINIC ZONE
THAT WILL BE JUST WEST/NW OF THE MPX AREA...WITH WINDS BACKING TO
THE SE. THIS SHOULD ALLOW 40 DEG TEMPERATURES TO SNEAK INTO ERN
AREAS FRIDAY. THIS FRONT DOES NOT LOOK TO START WORKING ACROSS
THE MPX CWA UNTIL FRIDAY NIGHT BASED ON AN ECMWF/GFS/NAM BLEND AS
A RAPIDLY DEEPENING SFC LOW MOVES UP FROM NEAR SIOUX FALLS UP TO
THE ARROWHEAD. NO OTHER WAY TO EXPLAIN THE CAA BEHIND THIS FRONT
FRIDAY NIGHT OTHER THAN AS INTENSE...WITH WIND ADVY STRENGTH WINDS
LOOKING LIKELY AND TEMPERATURES LIKELY DROPPING 20 DEGREES OR MORE
WITHIN AN HOUR OR TWO. THIS WILL QUICKLY TURN ANY PRECIP OVER TO
SNOW...THOUGH TRACK OF THE LOW WILL KEEP PRIMARY BAND OF SNOW
ACROSS NW MN.
LOOKING AT POTENTIAL HEADLINES...THERE WILL BE THE POSSIBILITY FOR
TWO WITH THIS SYSTEM...A WINTER WEATHER AND WIND ADVY. AT THE
MOMENT...THE MOST LIKELY PLACE THAT MAY NEED A WINTER WX ADVY IS
THE FAR NW CWA. THIS IS WHERE THE HIGHEST POTENTIAL FOR SEEING
FZRA WILL BE THURSDAY NIGHT...FOLLOWED BY THE POTENTIAL FOR A FEW
INCHES OF SNOW FRIDAY NIGHT INTO SATURDAY DEPENDING ON HOW FAR SE
THE DEFORMATION PRECIP BAND SETS UP. AS FOR THE WIND ADVY...FRIDAY
NIGHT IS LOOKING QUITE BREEZY...ESPECIALLY ON THE ECMWF...WHICH
DEVELOPS SUSTAINED WINDS IN WRN MN IN EXCESS OF 30 MPH...WITH
GUSTS OVER 40 MPH IN RESPONSE TO IT SENDING A 990 LOW OVER TO THE
WEST END OF LAKE SUPERIOR AS A 1030 MB HIGH MOVES INTO THE BLACK
HILLS.
AS FOR THE REST OF THE FORECAST...IT IS LOOKING COOLER...ESPECIALLY
SATURDAY THROUGH MONDAY...WHEN BELOW ZERO LOWS WILL RETURN WITH
HIGHS IN THE SINGLE DIGITS AND TEENS...THOUGH WE COULD GET WARMER
THAN THAT AS WARM TEMPS THURSDAY/FRIDAY WILL LIKELY PUNCH A LOT OF
HOLES IN THE SNOWPACK OUTSIDE OF THE NW CWA...WHICH WILL LIKELY
GET SOME SNOW FRIDAY NIGHT. BY THE MIDDLE OF THE WEEK...BOTH THE
GFS/ECMWF SHOW TEMPERATURES MODERATING OUT AHEAD OF CLIPPER COMING
DOWN TUESDAY NIGHT/WEDNESDAY. ALSO INTERESTING IS THAT AS NEXT
WEEK GROWS CLOSER...THE GFS/ECMWF CONTINUE TO BACK OFF ON THE
EXTENT TO WHICH THE ARCTIC AIR MAKES IN INTO THE US...WITH EACH
NEW RUN SEEMING TO KEEP IT FURTHER AND FURTHER NORTH...SO THAT WILL
BE SOMETHING TO WATCH. AS FOR WEATHER...AFTER THURSDAY NIGHT
THROUGH SATURDAY IT LOOKS DRY.
&&
.AVIATION.../06Z TAF ISSUANCE/
BATCH OF MVFR CEILINGS MOVING QUICKLY EAST AND SHOULD EXIT
KEAU/KRNH BY 08Z. NEXT LOBE OF MVFR CEILINGS IN ERN ND WHICH IS
MOVING ESE. LATEST RAP BRUSHES AXN/STC/RNH AND HAVE ADDED A TEMPO
GROUP FOR SOME BROKEN 2000-2500 FOOT CEILINGS. OTHERWISE SOME
GUSTY WNW WIND THROUGH MIDDAY UNTIL SURFACE RIDGE APPROACHES.
QUICK TRANSITION TO SOUTHERLY WINDS LATER WED AFTERNOON.
KMSP... BROKEN MID LEVEL CLOUDS THE REST OF THE NIGHT. LOBE OF STRATUS
IN ERN ND AROUND 2000 FEET AGL AND MOVING ESE. THIS SHOULD REMAIN
NORTH OF KMSP BUT HAVE ADDED SOME SCATTERED CLOUDS FOR THIS AROUND
11Z. ONLY A SMALL CHANCE OF THIS GOING BROKEN. WINDS GUSTING OVER
20 KNOTS SHOULD REMAIN WEST OR WNW BEFORE BECOMING SOUTH LATE WED
AFTERNOON.
/OUTLOOK FOR KMSP/
THU...VFR MORNING BECOMING MVFR CIGS/VSBYS LATE AFTERNOON.
THU NIGHT...IFR CIGS/VSBYS WITH LIFR AND -FZRA POSSIBLE. WINDS SE
AT 10-15KTS.
FRI...IFR WITH -RA. LIFR POSSIBLE. WINDS SSW AT 5-10KTS.
SAT...MVFR WITH -RASN POSSIBLE. COLD FRONT PASSAGE EARLY. WINDS
SSW AT 10KTS BECOMING NW AT 15G25KTS.
&&
.MPX WATCHES/WARNINGS/ADVISORIES...
MN...NONE.
WI...NONE.
&&
$$
MPG/TDK
AREA FORECAST DISCUSSION
NWS TWIN CITIES/CHANHASSEN MN
1114 PM CST TUE JAN 8 2013
.UPDATE...
UPDATED FOR AVIATION DISCUSSION BELOW.
&&
.DISCUSSION...
/ISSUED AT 310 PM CST TUE JAN 08 2013/
SCHEDULED SHORT WAVE TROUGH MOVING ACROSS EASTERN DAKOTAS THIS
AFTERNOON. THIS GENERATED SOME LIGHT SNOW SHOWERS AND SPRINKLES AS
IT MOVED INTO NORTHWEST MINNESOTA. THIS FEATURE IS PROGGED TO MOVE
EAST DURING THE EVENING AND SHOULD TAKE THE CHANCE OF LIGHT SNOW
WITH IT. WILL CONTINUE SMALL CHANCE POPS OVER THE NORTHEAST
QUADRANT OF THE CWA THIS EVENING. SOME INDICATIONS OF ANOTHER WEAK
WAVE ROTATING AROUND THE TROUGH INTO WESTERN MN THIS EVENING...AND
SPREADING BAND OF MID CLOUDS AND POSSIBLE SNOW SHOWERS ALONG THE
SECONDARY FRONT AS IT MOVES THROUGH EASTERN MN AROUND 08Z. WILL
HAVE TO MONITOR THIS EVENING AND SEE IF THIS WILL BE STRONG ENOUGH
TO GENERATE A FEW SNOW SHOWERS. WINDS ARE EXPECTED TO INCREASE
BEHIND FRONT AND BECOME A BIT GUSTY OVERNIGHT INTO EARLY
WEDNESDAY...MAINLY WEST UNTIL RIDGE BUILDS INTO THE AREA ONCE
AGAIN AND CLEARS THE SKY.
WEDNESDAY NIGHT AND INTO THURSDAY APPEARS DRY. MODELS HAVE TRENDED
SLOWER WITH SOUTHWEST CUTOFF LOW PRESSURE SYSTEM. MODELS WILL
CONTINUE TO HAVE PROBLEMS WITH TIMING OF EJECTION OF THIS LOW
UNTIL THE "KICKER TROUGH" MOVES SHORE ON OVER THE WESTERN CONUS.
WILL FOLLOW A GEM/ECMWF MOVEMENT OF THE SYSTEM WHICH WILL KEEP THE
AREA DRY THROUGH 18Z THU. WILL SPREAD LIKELY POPS INTO SOUTHERN CWA
DURING THE AFTERNOON. MAY NOT QUITE MAKE IT OVER THE NORTHERN CWA
BY 00Z FRI. THERMAL STRUCTURE OF THE ATMOSPHERE DOES FAVOR
RAIN...BUT THE LEADING EDGE OR FIRST HOUR OR SO OF THE INITIAL
SURGE OF RAIN MAY BE LIGHT FREEZING RAIN. WILL KEEP IT LIQUID
DURING THE DAY THURSDAY CONSIDERING TIMING OF THE PRECIPITATION
MOVING IN DURING THE WARMER PORTION OF THE DAY. SURFACE
TEMPERATURES EXPECTED TO WARM THROUGH THE MID AND UPPER 30S
THURSDAY AFTERNOON.
INTO THURSDAY NIGHT AND FRIDAY...THE BAROCLINIC ZONE SHIFTS SLOWLY
EAST...MAINLY ON FRIDAY. THIS SHOULD LEAVE MOST IF NOT ALL OF THE
CWA IN THE WARM SECTOR AHEAD OF COLD FRONT THURSDAY NIGHT.
TEMPERATURES SHOULD REMAIN WARM ENOUGH FOR JUST RAIN OVER THE
EASTERN TWO THIRDS OF THE AREA. FOG AND DRIZZLE MAY BE MORE OF AN
ISSUE. THE WEST WILL SEE THE POSSIBILITY OF LIGHT FREEZING RAIN.
SREF PLUMES/FREEZING RAIN PROBABILITIES ARE STILL RATHER HIGH
DURING THIS PERIOD...SO DONT WANT TO REMOVE THAT THREAT JUST YET.
AS THE OVERALL TRENDS BECOME CLEARER...WE MAY BE ABLE TO DO THAT
IN LATER FORECASTS.
THE GEM AND ND ECMWF ARE TRENDING MORE SURFACE LOW DEVELOPMENT TO
THE NORTHEAST AS THE TROUGH DEVELOPS AND LIFTS ENERGY RAPIDLY
ACROSS THE EASTERN DAKOTAS AND NORTHERN MINNESOTA FRIDAY NIGHT
INTO SATURDAY. THIS SPREADS AN AREA OF SNOW OVER NORTHERN
MINNESOTA...AND MAY AFFECT OUR NORTHERN CWA IN MN WITH A CHANGE TO
SOME ACCUMULATING SNOW. AGAIN...UNTIL THE WESTERN CONUS TROUGH
COMES ASHORE...OVERALL DEVELOPMENT AND MOVEMENT OF SYSTEMS STILL
IN DOUBT.
MUCH COOLER AIR/BELOW NORMAL FOLLOWS THIS SYSTEM AS IT MOVES ACROSS THE
NORTHERN CONUS. NORTHWEST FLOW ALOFT BECOMES ESTABLISHED AND
SHOULD HELP DRAW THE COLDER AIR IN FROM CANADA THROUGH AT LEAST
THROUGH THE END OF NEXT WEEK.
&&
.AVIATION.../06Z TAF ISSUANCE/
BATCH OF MVFR CEILINGS MOVING QUICKLY EAST AND SHOULD EXIT
KEAU/KRNH BY 08Z. NEXT LOBE OF MVFR CEILINGS IN ERN ND WHICH IS
MOVING ESE. LATEST RAP BRUSHES AXN/STC/RNH AND HAVE ADDED A TEMPO
GROUP FOR SOME BROKEN 2000-2500 FOOT CEILINGS. OTHERWISE SOME
GUSTY WNW WIND THROUGH MIDDAY UNTIL SURFACE RIDGE APPROACHES.
QUICK TRANSITION TO SOUTHERLY WINDS LATER WED AFTERNOON.
KMSP... BROKEN MID LEVEL CLOUDS THE REST OF THE NIGHT. LOBE OF STRATUS
IN ERN ND AROUND 2000 FEET AGL AND MOVING ESE. THIS SHOULD REMAIN
NORTH OF KMSP BUT HAVE ADDED SOME SCATTERED CLOUDS FOR THIS AROUND
11Z. ONLY A SMALL CHANCE OF THIS GOING BROKEN. WINDS GUSTING VOER
20 KNOTS SHOULD REMAIN WEST OR WNW BEFORE BECOMING SOUTH LATE WED
AFTERNOON.
/OUTLOOK FOR KMSP/
THU...VFR MORNING BECOMING MVFR CIGS/VSBYS LATE AFTERNOON.
THU NIGHT...IFR CIGS/VSBYS WITH LIFR AND -FZRA POSSIBLE. WINDS SE
AT 10-15KTS.
FRI...IFR WITH -RA. LIFR POSSIBLE. WINDS SSW AT 5-10KTS.
SAT...MVFR WITH -RASN POSSIBLE. COLD FRONT PASSAGE EARLY. WINDS
SSW AT 10KTS BECOMING NW AT 15G25KTS.
&&
.MPX WATCHES/WARNINGS/ADVISORIES...
MN...NONE.
WI...NONE.
&&
$$
DWE/TDK
AREA FORECAST DISCUSSION
NWS ST LOUIS MO
357 AM CST WED JAN 9 2013
.SHORT TERM...
ISSUED AT 349 AM CST WED JAN 9 2013
(TODAY)
WEAK COLD FRONT CONTINUES TO MOVE SOUTHEAST THROUGH FORECAST AREA
EARLY THIS MORNING WITH SOME LIGHT RAIN OUT AHEAD OF IT.
FRONT SHOULD WEAKEN/EXIT FORECAST AREA BY MID MORNING. AS FOR THE
RAIN...IT IS MAKING PROGRESS TO THE EAST...SO SHOULD COME TO AN END
BY BEGINNING OF FORECAST PERIOD. SO MAIN ISSUE TO DEAL WITH TODAY
WILL BE THE LINGERING CLOUD COVER AND HOW FAST IT WILL THIN OUT.
AREAS ALONG AND NORTH OF I-70 TO SEE THE MOST SUNSHINE TODAY...WHILE
AREAS TO THE SOUTH TO REMAIN MOSTLY CLOUDY THIS MORNING...BEFORE
SCATTERING OUT LATE THIS AFTERNOON. ALSO...WINDS TO VEER TO THE
WEST...THEN EVENTUALLY TO THE NORTH THIS AFTERNOON...BEHIND THIS
BOUNDARY.
HIGH TEMPS HARD TO PIN DOWN FOR TODAY...DEPENDING ON WHAT THE CLOUDS
ULTIMATELY DO TODAY AS WELL AS STRENGTH OF CAA WITH FRONTAL BOUNDARY.
FOR NOW WENT WITH UPPER 40S NORTHEAST TO THE MID 50S OVER CENTRAL
AND SOUTHERN MO.
BYRD
&&
.LONG TERM...
ISSUED AT 349 AM CST WED JAN 9 2013
(WEDNESDAY NIGHT - FRIDAY NIGHT)
MODELS CONTINUE TO COME INTO BETTER AGREEMENT ON A SLOWER EVOLUTION
OF UPPER LEVEL LOW TAKING IT FROM CNTRL TX THURSDAY MORNING TO AN
OPEN...BUT POTENT...WAVE ACROSS THE CWA THURSDAY NIGHT. THE LOW IS
IN THE PROCESS OF MAKING THE LEFT HAND TURN AND HEAD TOWARDS STHRN TX
DUE TO STRONG ENERGY ENTERING THE PACIFIC NW. ECMWF IS NOW ONE OF
THE FASTER MODELS WHILE THE GFS HAS TRANSITIONED TO A LITTLE DEEPER
AND CONSEQUENTLY SLOWER SOLUTION. HAVE BACKED OFF POPS CONSIDERABLY
THIS EVENING AND THEN TIGHTENED THE GRADIENT UP SOME AFTER MIDNIGHT
DUE TO THE SLOWER SOLUTIONS. SFC WARM FRONT TO LIFT THRU THE CWA
THURSDAY AND THEN PACIFIC COLD FRONT THURSDAY EVENING. THINKING ALL
PRECIP WILL BE EAST OF AREA BY 12Z FRIDAY. SHOULD BE A DECENT PUSH
OF WAA PRECIP TONIGHT INTO THURSDAY MORNING. COULD BE A BREAK IN THE
PRECIP BEFORE ANOTHER ROUND ASSOC WITH THE COLD FRONT THURSDAY LATE
AFTN/EVNG/OVERNIGHT. SYSTEM WILL BE TAPPING INTO SUBTROPICAL
MOISTURE. PWATS REMAIN CLIMATOLOGICALLY HIGH. DPS RISE INTO AT LEAST
THE LOWER 50S FOR THE SERN PORTION OF THE CWA THURSDAY NIGHT. 850
DPS OF +10C COVER A GOOD PORTION OF THE CWA THURSDAY AFTN/EVNG.
THUNDER IS STILL POSSIBLE EVEN THO PARAMETERS DON`T LOOK AS GOOD AS
THEY DID LAST NIGHT. WITH THE STRENGTH OF THE FORCING EXPECTED WITH
THIS EVENT...SHOULD BE SUFFICIENT FOR THUNDER. LOW/PRECIP PULL AWAY
FRIDAY LEAVING THE CWA IN SW FLOW AT THE SFC AND ALOFT. 925MB AND
850MB TEMPS OF +10C TO +14C FRIDAY AFTN WILL LEAD TO A VERY WARM DAY
WITH HIGHS IN THE 60S. CLIMATE SECTION OF AFD HAS HIGH/HIGH LOW
RECORDS FOR STL/COU/UIN FOR FRIDAY.
(SATURDAY - TUESDAY)
THIS MARKS THE BEGINNING OF A TRANSITION PERIOD. SATURDAY WILL BE THE
LAST WARM DAY FOR A WHILE. STRONG ARCTIC COLD FRONT PUSHES THRU THE
CWA DURING THE DAY. HIGHS...ESP ACROSS THE NORTH WILL BE IN THE
MORNING...WITH FALLING TEMPS BEHIND THE FRONT. THE FRONT INITIALLY PASSES
THRU DRY...BUT GETS HUNG UP JUST TO THE SE OF THE CWA AS WAVE OF LOW
PRESSURE RIDES NE ALONG THE FRONT SUNDAY NIGHT AND MONDAY. THERE ARE
PLENTY OF ISSUES TO WORK OUT DURING THIS TIME FRAME. THE GEM IS THE
MOST AGGRESSIVE WITH PUSHING THE FRONT SE AND HAS IT ALIGNED FROM
LAKE CHARLES LA TO THE STHRN TIP OF OH BY 6Z MONDAY.
CONVERSELY...THE GFS IS THE SLOWEST AND HAS IT FROM TEXARKANA TO THE
MO BOOTHEEL TO DETROIT. THE ECMWF IS IN BETWEEN. THIS HAS MAJOR
IMPLICATIONS ON PLACEMENT OF PRECIP AND DEPTH OF COLD AIR WHICH
DETERMINES P-TYPE. THE GFS SOLUTION WOULD MEAN PLENTY OF COLD RAIN
WHILE THE GEM SOLUTION KEEPS MOST OF THE PRECIP SE OF THE CWA. RIGHT
NOW I DON`T HAVE ENOUGH TO GO ON TO MAKE AN EDUCATED GUESS AS TO
WHICH SOLUTION IS RIGHT. IT ALL DEPENDS ON HOW FAR SE THE FRONT CAN
GET BEFORE IT GETS HUNG UP AND ONLY TIME WILL TELL. THERE ARE
INDICATIONS THAT THE FRONT MAY BECOME STATIONARY TO OUR SE FOR A
PORTION OF THE UPCOMING WEEK. AGAIN...DEPENDING ON WHERE IT SETS UP
WILL BE CRITICAL FOR OUR SE ZONES UNTIL THE FRONT MOVES. THIS IS A
SET-UP THAT CERTAINLY BEARS WATCHING AS OVERRUNNING SITUATIONS LIKE
THIS CAN PRODUCE PLENTY OF MIXED PRECIP. ONE THING THAT IS FOR SURE
IS THAT NEXT WEEK WILL BE MUCH COLDER THAN THE CURRENT ONE. THE
ENERGY THAT GOT THE UPPER LOW MOVING WILL PHASE THE JET
STREAMS...WHICH IS WHAT ALLOWS THE ARCTIC FRONT TO SAG INTO THE CWA.
THE H500 PATTERN TRANSITIONS TO A BROAD TROF ACROSS THE CNTRL CONUS
WITH THE MEAN AXIS EXTENDING FROM HUDSON BAY SW TO THE DESERT SW FOR
THE BEGINNING OF THE WEEK. THIS SET UP DOESN/T FAVOR MOVING THE SFC
FRONT MUCH. TOWARDS THE MIDDLE OF THE WEEK...THE MEAN TROUGH ON THE
GFS IS MORE PROGRESSIVE THAN THE ECMWF WHICH STILL WANTS TO CUT OFF
THE ENERGY AT THE BASE OF THE TROUGH. PLENTY GOING ON TO WORRY ABOUT
BEFORE WE GET TO THIS POINT.
MILLER
&&
.AVIATION...
ISSUED AT 1131 PM CST TUE JAN 8 2013
PRECIPITATION OVER NORTHERN ARKANSAS AND SOUTHERN MISSOURI HAS
MADE A BIT MORE NORTHWARD PROGRESSION THIS EVENING THAN PREVIOUSLY
THOUGHT. HOWEVER...IT APPEARS THAT A MAJORITY OF THE PRECIPITATION
SHOULD REMAIN SOUTH OF TAF SITES AND THUS HAVE NOT INCLUDED
MENTION IN THIS TAF PACKAGE. HOWEVER...CANNOT RULE OUT SOME
SPRINKLES FOR KCOU...KSTL...KSUS...AND KCPS...THOUGH IMPACTS TO
VISIBILITY AND CIGS SHOULD BE MINIMAL. HAVE ALSO CONTINUED MENTION
OF LLWS FOR THE METRO TAF SITES THROUGH 10Z TONIGHT...WITH MODEL
SOUNDINGS CONTINUING TO SUPPORT LLWS CRITERIA...THOUGH IT REMAINS
MARGINAL. OTHERWISE...EXPECT VFR CONDITIONS TO PREVAIL THROUGH
THE FORECAST PERIOD...WITH SOUTHERLY WINDS BECOMING WESTERLY AS A
WEAK COLD FRONT MOVES THROUGH THE AREA...AND EVENTUALLY NORTHERLY
LATE IN THE PERIOD.
SPECIFICS FOR KSTL...
HAVE CONTINUED MENTION OF LLWS IN THE TAF THROUGH 10Z GIVEN
CONTINUED INDICATIONS FROM RAP AND LOCAL WRF MODEL SOUNDINGS OF A
LLJ AROUND 35-40KT AT 1500-2000FT. ANOTHER CONCERN TONIGHT IS THE
NORTHWARD PROGRESSION OF PRECIPITATION OVER SOUTHERN
MISSOURI...WHICH SHOULD REMAIN SOUTH OF THE TERMINAL. HOWEVER...CANNOT
RULE OUT SOME SPRINKLES AT KSTL TONIGHT...THOUGH IMPACTS WOULD BE
MINIMAL.
OTHERWISE...DRY AND VFR CONDITIONS WILL CONTINUE THROUGH A
MAJORITY OF THE FORECAST PERIOD...WITH SOUTHERLY WINDS VEERING TO
THE WEST AS A WEAK COLD FRONT PASSES...AND EVENTUALLY TO THE NORTH
BY THE END OF THE PERIOD. GIVEN TIMING INCONSISTENCIES WITH THE
NEXT SYSTEM PROGGED TO MOVE INTO THE AREA LATE WEDNESDAY
NIGHT/EARLY THURSDAY...HAVE KEPT PRECIPITATION MENTION OUT OF THE
TAF FOR NOW AND WILL DEFER TO FUTURE ISSUANCES WHEN THE TIMING
BECOMES MORE CERTAIN.
JP
&&
.CLIMATE...
ISSUED AT 349 AM CST WED JAN 9 2013
HIGH HIGH LOW
ST. LOUIS 74/1911 60/1890
COLUMBIA 67/1911 48/1890
QUINCY 58/1911 38/2007
&&
.LSX WATCHES/WARNINGS/ADVISORIES...
MO...NONE.
IL...NONE.
&&
$$
WFO LSX
AREA FORECAST DISCUSSION...UPDATED AVIATION
NWS ST LOUIS MO
1151 PM CST TUE JAN 8 2013
.UPDATE...
ISSUED AT 936 PM CST TUE JAN 8 2013
PRECIP HAS HELD TOGETHER BETTER THAN PROGD BY SOME OF THE
GUIDANCE. HAVE THEREFORE INCREASED POPS ACROSS THE SRN HALF OF THE
CWA. THE NRN EDGE OF RADAR RETURNS APPEARS TO BE DISSIPATING
SOMEWHAT...BUT WILL PULL SLIGHT CHANCE POPS FURTHER NWD IN CASE
THESE RETURNS HOLD TOGETHER. RAISED TEMPS OVERNIGHT A LITTLE AS
CLOUD COVER HAS HINDERED ANY COOLING AND WITH COOLER AIR NOT
ARRIVING UNTIL WED MORNING.
ISSUED AT 704 PM CST TUE JAN 8 2013
UPDATE TO INCREASE CLOUDS THRU THE NIGHT. ALSO INCREASED POPS
ACROSS SRN PORTIONS OF THE CWA. PRECIP CURRENTLY OVER SW MO
CONTINUES TO MOVE NEWD AND SHUD REACH SRN COUNTIES LATE THIS
EVENING. GOING FORECAST MAY STILL BE TOO SLOW BASED ON LATEST
RADAR TRENDS. HOWEVER...LATEST RAP/HRRR GUIDANCE SUGGESTS FORCING
WILL DIMINISH SOMEWHAT THRU THE NIGHT WITH PRECIP BECOMING MORE
SCT THAN IS CURRENTLY. ANOTHER AREA OF CONCERN IS THE CDFNT MOVING
INTO NWRN MO. GUIDANCE SUGGESTS THIS FNT MAY HELP TO PUSH PRECIP S
OF THE REGION. BELIEVE THE FNT IS MOVING TOO SLOWLY TO HAVE MUCH
IMPACT THIS EVENING...BUT MAY MOVE PRECIP FURTHER S FASTER LATE
TONIGHT. WILL CONTINUE TO MONITOR AND UPDATE AS NEEDED.
TILLY
&&
.SHORT TERM...
ISSUED AT 335 PM CST TUE JAN 8 2013
(TONIGHT)
A NRN STREAM SHORTWAVE WILL PASS NORTH OF THE AREA TONIGHT ALTHOUGH
IT WILL DRAG A WEAK CDFNT THROUGH THE CWA. ATTM NO PCPN IS EXPECTED
WITH THE CDFNT DUE TO THE INITIALLY DRY AIR MASS PER 12Z SGF
SOUNDING...LIMITED MOISTURE ACCOMPANYING THE NRN STREAM
SHORTWAVE...AND UNFAVORABLE DYNAMICS THIS FAR SOUTH OF THE VORT MAX.
THE PRIMARY EFFECT OF THE CDFNT WILL BE TO CAUSE WINDS TO VEER FM
SLY TO WLY OVERNIGHT. ALTHOUGH THE NAM/SREF SEEM TO BE OVERDOING THE
LOW LEVEL MOISTURE BASED ON THE LATEST OBS...MID-LEVEL MOISTURE
SHOULD BEGIN MOVING NWD TONIGHT IN RESPONSE TO A STRONG LOW PRESSURE
SYSTEM IN NRN MEXICO/SRN TX. SOME PCPN HAS ALREADY DVLPD OVER AR
AHEAD OF THE SRN SYSTEM AND IT IS POSSIBLE THAT THERE MAY BE ENOUGH
LIFT TO SUPPORT A FEW SPRINKLES ACROSS THE SRN CWA.
KANOFSKY
&&
.LONG TERM...
ISSUED AT 335 PM CST TUE JAN 8 2013
(WEDNESDAY THROUGH TUESDAY)
A GOOD POTENTIAL FOR SIGNIFICANT QPF IS EXPECTED FOR WED NGT THROUGH
THU NGT AS THE UPPER LEVEL LOW OVER OLD MEXICO MOVES SLOWLY NEWD
THROUGH THE SRN PLAINS WED AND WED NGT...THEN EVENTUALLY MOVES
NEWD THROUGH MO THU NGT. PREFER THE MORE NRN SOLUTION OF THE 500
MB LOW TRACK OF THE NAM AND ECMWF MODELS OVER THE GFS. MOST OF THE
PRECIPITATION SHOULD REMAIN S OF OUR FORECAST AREA ON WED...BUT
THEN SPREAD NEWD INTO MUCH OF THE REGION WED NGT AS A STRONG SLY
LOW LEVEL JET BRINGS LOW LEVEL MOISTURE NWD INTO MUCH OF MO AND
SRN IL. SHOWERS AND AT LEAST A FEW THUNDERSTORMS CAN BE EXPECTED
ON THU AS A WEAK SFC LOW AND WARM FRONT LIFT NWD INTO SRN
MO...WITH INCREASING UPPER LEVEL DIVERGENCE OVER OUR AREA AHEAD OF
THE APPROACHING UPPER LEVEL TROUGH. MUCH OF THE PRECIPITATION
SHOULD SHIFT E OF OUR AREA BY LATE THU NGT AS THE UPPER LEVEL LOW
OPENS UP AND WEAKENS AS IT MOVES TOWARDS THE GREAT LAKES REGION.
UNSEASONABLY WARM WEATHER WILL CONTINUE ON FRI WITH S-SWLY LOW
LEVEL WINDS ALONG WITH A CLEARING SKY. BOTH THE NAM AND ECMWF
MODELS FORECAST 850 MB TEMPERATURES OF AROUND 12 DEGREES C BY 00Z
SAT ACROSS MUCH OF OUR AREA. WILL LIKELY HAVE HIGHS IN THE LOWER
60S ACROSS MOST OF THE AREA ON FRI. SAT WILL BE THE LAST DAY OF
ABOVE NORMAL TEMPERATURES AS A COLD FRONT DROPS SOUTHEASTWARD
THROUGH OUR FORECAST AREA LATE FRI NGT AND SAT. ALTHOUGH THE FRONT
SHOULD MOVE THROUGH DRY THE MODELS DO GENERATE POST FRONTAL
PRECIPITATION SAT NGT AS A WEAK SFC WAVE MOVES ALONG THE FRONT
WITH AN APPROACHING POSITIVELY TILTED UPPER LEVEL TROUGH WELL WEST
OF THE AREA. LOOKS LIKE MOST OF THE PRECIPITATION WILL BE ACROSS
SERN MO AND SWRN IL IN THE WARMER AIR...BUT COULD NOT RULE OUT A
LITTLE LIGHT SNOW N AND W OF STL IN THE COLDER AIR. THE POTENTIAL
FOR AT LEAST LIGHT PRECIPITATION MAY CONTINUE ACROSS SERN MO AND
SWRN IL UNTIL MON WHEN A STRONG SFC RIDGE OVER THE NRN PLAINS
FINALLY BUILDS SEWD INTO MO WITH THE COLD FRONT SHIFTING WELL SE
OF OUR AREA. MUCH COLDER...MORE SEASONAL TEMPERATURES CAN BE
EXPECTED SUN THROUGH TUE.
GKS
&&
.AVIATION...
ISSUED AT 1131 PM CST TUE JAN 8 2013
PRECIPITATION OVER NORTHERN ARKANSAS AND SOUTHERN MISSOURI HAS
MADE A BIT MORE NORTHWARD PROGRESSION THIS EVENING THAN PREVIOUSLY
THOUGHT. HOWEVER...IT APPEARS THAT A MAJORITY OF THE PRECIPITATION
SHOULD REMAIN SOUTH OF TAF SITES AND THUS HAVE NOT INCLUDED
MENTION IN THIS TAF PACKAGE. HOWEVER...CANNOT RULE OUT SOME
SPRINKLES FOR KCOU...KSTL...KSUS...AND KCPS...THOUGH IMPACTS TO
VISIBILITY AND CIGS SHOULD BE MINIMAL. HAVE ALSO CONTINUED MENTION
OF LLWS FOR THE METRO TAF SITES THROUGH 10Z TONIGHT...WITH MODEL
SOUNDINGS CONTINUING TO SUPPORT LLWS CRITERIA...THOUGH IT REMAINS
MARGINAL. OTHERWISE...EXPECT VFR CONDITIONS TO PREVAIL THROUGH
THE FORECAST PERIOD...WITH SOUTHERLY WINDS BECOMING WESTERLY AS A
WEAK COLD FRONT MOVES THROUGH THE AREA...AND EVENTUALLY NORTHERLY
LATE IN THE PERIOD.
SPECIFICS FOR KSTL...
HAVE CONTINUED MENTION OF LLWS IN THE TAF THROUGH 10Z GIVEN
CONTINUED INDICATIONS FROM RAP AND LOCAL WRF MODEL SOUNDINGS OF A
LLJ AROUND 35-40KT AT 1500-2000FT. ANOTHER CONCERN TONIGHT IS THE
NORTHWARD PROGRESSION OF PRECIPITATION OVER SOUTHERN
MISSOURI...WHICH SHOULD REMAIN SOUTH OF THE TERMINAL. HOWEVER...CANNOT
RULE OUT SOME SPRINKLES AT KSTL TONIGHT...THOUGH IMPACTS WOULD BE
MINIMAL.
OTHERWISE...DRY AND VFR CONDITIONS WILL CONTINUE THROUGH A
MAJORITY OF THE FORECAST PERIOD...WITH SOUTHERLY WINDS VEERING TO
THE WEST AS A WEAK COLD FRONT PASSES...AND EVENTUALLY TO THE NORTH
BY THE END OF THE PERIOD. GIVEN TIMING INCONSISTENCIES WITH THE
NEXT SYSTEM PROGGED TO MOVE INTO THE AREA LATE WEDNESDAY
NIGHT/EARLY THURSDAY...HAVE KEPT PRECIPITATION MENTION OUT OF THE
TAF FOR NOW AND WILL DEFER TO FUTURE ISSUANCES WHEN THE TIMING
BECOMES MORE CERTAIN.
JP
&&
.LSX WATCHES/WARNINGS/ADVISORIES...
MO...NONE.
IL...NONE.
&&
$$
WFO LSX
AREA FORECAST DISCUSSION...UPDATED
NWS BILLINGS MT
541 PM MST THU JAN 10 2013
.SHORT TERM...VALID FOR FRI AND SAT...
UPDATE TO FORECAST TO INCREASE THE EMPHASIS OF FREEZING DRIZZLE
IN THE FORECAST IN AREAS E AND S OF KBIL. KGGW HAD REPORTS OF
FREEZING DRIZZLE ALONG THE NE BORDER OF THE FORECAST AREA AND A
SPOTTER FROM FORSYTH CALLED WITH SLICK ROADS AND FREEZING DRIZZLE.
IN ADDITION...ABERDEEN HILL WEB CAMERA SHOWED FOG SO FREEZING
DRIZZLE WAS LIKELY THERE. RAP BUFKIT SOUNDINGS SUPPORTED EVENING
FREEZING DRIZZLE OVER SE MT AND THE KSHR AREA. ARTHUR
.PREVIOUS DISCUSSION...
DEEP UPPER TROF MOVING SLOWLY OVER THE INTERMOUNTAIN WEST THIS
AFTERNOON. STRONGLY DIFFLUENT FLOW ALOFT YIELDING WIDESPREAD
SNOWFALL FROM IDAHO INTO WESTERN AND CENTRAL MONTANA. UPPER
SUPPORT IS SLIDING SLOWLY EASTWARD AND SNOW HAS DEVELOPED AT
LIVINGSTON AND JUDITH GAP. COLD FRONT HAS PUSHED THROUGH MILES
CITY AND BILLINGS BUT IS NOT QUITE TO OUR FAR SOUTHEAST. TEMPS
WARMED INTO THE 40S/NEAR 50 AHEAD OF THE FROPA...BUT IS NOW
FALLING FROM BILLINGS NORTH...AND IS IN FACT ALREADY IN THE TEENS
AT JUDITH GAP WHERE NORTH WINDS ARE GUSTING TO 40 MPH. SO DESPITE
THE WARM DAY...TEMPS ARE IN THE PROCESS OF CRASHING.
UPCOMING WINTER STORM WILL IMPACT US IN A COUPLE OF DIFFERENT
PHASES. DIFFLUENT FLOW ALOFT AS ENERGY LIFTS OUT OF THE GREAT
BASIN WILL IMPACT OUR WEST WITH HEAVY SNOW TONIGHT. DRY MID LEVEL
AIR EXISTS TO THE EAST...BUT LOW STRATUS IS CURRENTLY SURGING
SOUTHWARD WITH THE COLD ADVECTION. MODELS SHOW THIS MOISTURE
BECOMING DEEP ENOUGH TO SUPPORT SOME LIGHT UPSLOPE PCPN...PERHAPS
IN THE FORM OF LIGHT FREEZING DRIZZLE AS SATURATED LEVEL EXTENDS
ONLY TO ABOUT -5C. STRONGER FORCING WILL NOT REACH OUR EAST UNTIL
LATE TONIGHT OR MORE LIKELY TOMORROW...BUT COULD HAVE SOME -FZDZ
IMPACT THE AREA PRIOR TO THE SNOWFALL.
FOR CENTRAL PARTS INCLUDING THE CITY OF BILLINGS...ENERGY FROM THE
SOUTH NOT EXPECTED TO REACH US UNTIL LATE TONIGHT...PERHAPS BY
10-12Z. THOUGH COULD SEE SOME LIGHT SNOW PRIOR TO THIS AS THE COLD
AIR AND UPSLOPE NE WINDS DEEPEN OVER TIME...BEST CHANCE OF
ACCUMULATING SNOW APPEARS TO BE IN THE 10-18Z FRIDAY TIME FRAME.
THE SNOW SHOULD BE HEAVY PER A SFC-600MB DENDRITIC LAYER PER THE
LATEST RAP. SNOW WILL BECOMING LIGHTER IN CENTRAL AND WEST PARTS
THROUGH THE DAY ON FRIDAY AS STRONGER BAROCLINICITY SHIFTS INTO
THE WESTERN DAKOTAS PER JET EMERGING FROM THE CENTRAL ROCKIES...
AND AS TEMPS CONTINUE TO BECOME COLDER AND WE LOSE THE DEEP
DENDRITIC LAYER. THAT BEING SAID...MOIST ISENTROPIC ASCENT SHOULD
KEEP LIGHT ACCUMULATING SNOW GOING INTO FRIDAY EVENING. GREATEST
SNOW AMOUNTS SHOULD BE ON THE NORTH SIDE OF THE BEARTOOTH
ABSAROKAS INCLUDING RED LODGE...WITH ACCUMS UP TO A FOOT OR A BIT
MORE.
FOR OUR EAST...FOCUS OF SNOWFALL WILL BE TOMORROW AND TOMORROW
NIGHT AS ENERGY SHIFTS INTO THE HIGH PLAINS...THOUGH THERE MIGHT
BE SOME AREAS WITH LESS THAN EXPECTED ACCUMULATION AS MAIN FORCING
SHIFTS QUICKLY INTO THE DAKOTAS...LEAVING THE WEAKER ISENTROPIC
ASCENT TO IMPACT THE AREA INTO EARLY SATURDAY.
TO SUMMARIZE SOME OF THE CHANGES THIS FORECAST PACKAGE...HAVE
DELAYED START TIME OF SNOW ESPECIALLY IN CENTRAL AND EAST PARTS
TONIGHT...AND INTRODUCED RISK OF -FZDZ TO OUR FAR EAST. GARCIA
METHOD IS CONSISTENT WITH MODEL QPF ON THE ORDER OF A HALF TO
THIRD OF AN INCH AND 20-25:1 SNOW RATIOS...OUTSIDE OF UPSLOPE
AREAS...SO HAVE LOWERED EXPECTED SNOW AMOUNTS A FEW INCHES...TO
THE 5 TO 9 INCH RANGE MOST AREAS. GUSTY NW WINDS MAY KEEP SHERIDAN
A BIT LESS THAN THIS. HAVE ALSO ADDED MENTION OF BLOWING SNOW TO
JUDITH GAP AND BRIDGER...TWO SPECIFIC AREAS WHICH EXPERIENCE
ENHANCED NORTH WINDS IN TIMES OF COLD ADVECTION.
IMPACTS FROM THIS EVENT WILL INCLUDE POOR TRAVEL DUE TO SNOW
COVERED ROADS...AND GUSTY WINDS/BLOWING SNOW/COLD WIND CHILLS
ESPECIALLY FOR EAST OF BILLINGS.
SYSTEM WILL WIND DOWN IN OUR EAST BY SATURDAY MORNING. COLD NW
FLOW WILL LINGER THEREAFTER...WITH MUCH BELOW NORMAL TEMPS THE
NEXT FEW DAYS.
JKL
.LONG TERM...VALID FOR SUN...MON...TUE...WED...THU...
MINIMAL CHANGES TO THE EXTENDED PERIOD THIS AFTERNOON. RELATIVELY
DRY NORTHWEST FLOW ALOFT WILL DOMINATE THE PATTERN THROUGH THE
PERIOD.
THE PATTERN THROUGH THE EXTENDED PERIOD LOOKS PRETTY DRY
OVERALL. THE EXCEPTION IS A DISTURBANCE MOVING OUT OF CANADA
ACROSS THE FORECAST AREA MONDAY EVENING THROUGH TUESDAY NIGHT.
CURRENTLY...SNOW ACCUMULATIONS LOOK TO BE MINOR.
GREATEST CONCERN DURING THE EXTENDED PERIOD CONTINUES TO BE WINDS
ALONG WITH BLOWING SNOW FOR SUNDAY AND INTO EARLY NEXT WEEK...AS A
TIGHT PRESSURE GRADIENT SETS UP FROM BILLINGS WEST. DOWNSLOPE FLOW
WILL SET UP...BUT DOES NOT LOOK LIKE THE TYPICAL WARM CHINOOK.
EXPECTED SNOW COVER AND NORTHWEST FLOW SHOULD LIMIT WARMUP FOR THE
WORK WEEK. HAVE OPTED FOR SLOWER WARMUP...AND KEPT INHERITED TEMPS
IN PLACE AT THIS TIME. AAG
&&
.AVIATION...
CLOUDS WILL BE INCREASING AND LOWERING ACROSS SOUTH CENTRAL
AND SOUTHEASTERN MONTANA THROUGH THIS EVENING AND OVERNIGHT...AND
SNOW WILL SPREAD FROM WEST TO EAST. IFR CONDITIONS AND/OR
LOWER...AS SEEN IN KLVM...WILL SPREAD EASTWARD WITH THE SNOW.
OTHERWISE...VFR CONDITIONS WILL PREVAIL AHEAD OF THE SNOW. AAG
&&
.PRELIMINARY POINT TEMP/POPS...
FRI SAT SUN MON TUE WED THU
-----------------------------------------------------------
BIL 007/008 903/013 000/018 001/020 013/029 022/034 017/031
++/S 81/B 01/B 11/Q 32/S 21/N 11/N
LVM 002/009 908/012 903/016 000/016 008/027 016/030 017/027
+9/S 50/B 01/B 11/Q 32/S 21/N 11/N
HDN 008/009 904/013 905/017 003/019 011/028 021/034 020/031
++/S 92/S 01/B 11/B 33/S 21/N 11/B
MLS 007/009 907/010 908/013 909/016 007/027 018/031 018/028
7+/S +2/S 11/B 11/B 23/S 21/B 11/B
4BQ 009/010 905/011 906/016 905/017 007/027 018/032 017/029
9+/S +3/S 01/B 11/B 33/S 31/N 11/U
BHK 006/010 907/005 907/009 910/013 002/025 014/030 018/027
7+/S +3/S 11/B 11/B 22/S 21/N 11/B
SHR 008/009 904/011 906/018 904/018 009/027 020/035 021/032
++/S 82/S 01/B 11/B 33/S 31/B 10/U
&&
.BYZ WATCHES/WARNINGS/ADVISORIES...
MT...WINTER STORM WARNING IN EFFECT UNTIL 6 AM MST SATURDAY FOR
ZONES 28-29-34-35-38>42-56-57-63>68.
WINTER STORM WARNING IN EFFECT UNTIL 6 PM MST SATURDAY FOR
ZONES 30>33-36-37-58.
WY...WINTER STORM WARNING IN EFFECT UNTIL 6 PM MST SATURDAY FOR
ZONES 98-99.
&&
$$
WEATHER.GOV/BILLINGS
AREA FORECAST DISCUSSION
NWS GRAND FORKS ND
140 AM CST WED JAN 9 2013
.DISCUSSION...
HAVE ISSUED A WIND ADVISORY THROUGH 12Z THIS MORNING ALONG AND
WEST OF THE RED RIVER VALLEY. GETTING WINDS GUSTING TO 45MPH AT
TIMES WITH A PRESSURE RISE MAX MOVING INTO THE AREA. ALSO GETTING
SOME BLOWING SNOW IN THE NORTH.
&&
.AVIATION...
WIND GUSTS COMING NOW AND WILL BE WITH US THRU THE NIGHT IN
DVL/GFK/FAR/TVF SITES....SPREADING FROM WEST TO EAST. HIGHEST
WINDS LIKELY AT DVL 04Z-07Z WITH NR 40 KTS FROM WEST- NORTHWEST
DIRECTION. WINDS WILL DIMINISH BY 12Z. CLOUDS MOVING IN AFTER
CLEARING MOSTLY IN THE MVFR RANGE AND THESE SHOULD CLEAR OUT OF NE
ND 11Z-14Z PERIOD.
&&
.PREV DISCUSSION... /ISSUED 922 PM CST TUE JAN 8 2013/
DISCUSSION...
SFC OBS SHOW THE MAIN SFC TROUGH NOW MOVING THROUGH THE RED RIVER
VALLEY. WATER VAPOR SHOWS UPPER LOW AND SFC LOW NORTHWEST OF
WINNIPEG AND A SURGE OF CLOUDS AND WINDS ON THE BACKSIDE OF THE
LOW MOVING FROM REGINA AREA WHERE IT WAS LATE THIS AFTN THEN INTO
NW ND 00Z-01Z...THEN NOW MOVING THRU RUGBY-ROLLA AT 02-03Z. THIS
SURGE OF CLOUDS ROTATING EAST-SOUTHEAST AROUND THE LOW IN MANITOBA
WILL CONTINUE TO MOVE INTO NE ND/NRN RRV THRU 06Z. NAM 3 HR
PRESSURE RISES SHOWS A HEALTHY 5 MB/3 HR PRESSURE RISE INTO NE ND
06Z-09Z PERIOD AND 1000-850 MB LOW LEVEL LAPSE RATES DECENT (7 TO
8C/KM) MOVING THRU AS WELL. THIS IS ENOUGH FOR A 3-4 HR PERIOD OF
GOOD MIXING OF THE 45-50 KTS 925-850 MB LAYER. SEEING WIND GUSTS
TO 40 KTS OR HIGHER AT KMIB...CYBR AND NR THAT AT KRUG (RUGBY). DO
EXPECT THIS PERIOD OF WIND GUSTS TO NR 40 KTS TO SPREAD EAST
THE NEXT FEW HOURS. DUE TO RATHER SHORT NATURE OF EVENT AND ALSO
BECAUSE IT IS CAUSING SLICK ROADS DUE TO DRIFTING...COORD WITH WFO
BIS AND ISSUED A SPECIAL WX STATEMENT FOR AREAS ALONG AND NORTH OF
COOPERSTOWN-HILLSBORO LINE.
OTHERWISE...TEMPS STILL MILD BUT WILL FALL OFF LATER AS COOLER AIR
MOVES IN WITH STRATOCU. LATEST RAP AND 00Z NAM ALL SHOW CLEARING
MOVING BACK IN BEHIND CLOUDS INTO NE ND TOWARD 12Z. CLOUDS TO
CLEAR OUT OF NW MN MORE TOWARD 15Z WED.
PREV DISCUSSION... /ISSUED 300 PM CST TUE JAN 8 2013/
SHORT TERM...
MAIN FORECAST HEADACHES FOR THE PERIOD WILL BE ENDING OF PRECIP
ALONG WITH WINDS TONIGHT...AND THEN WHAT HAPPENS WITH THE SYSTEM
COMING IN THURSDAY/FRIDAY.
AN UPPER LOW CURRENTLY ROTATING ALONG THE SASKATCHEWAN/MANITOBA
BORDER WILL CONTINUE EASTWARD INTO ONTARIO TONIGHT. THE SFC LOW
WILL MOVE EASTWARD ALSO...BRINGING A STRONG GRADIENT WITH WEST
WINDS. DEFORMATION BANDS THAT ARE CURRENTLY PRODUCING SNOW OVER
THE RED RIVER VALLEY AND POINTS EASTWARD WILL CONTINUE TO MOVE
EAST THIS EVENING. WILL MAKE LAST MINUTE ADJUSTMENTS FOR GOING
RADAR TRENDS...BUT FOR NOW WILL KEEP HIGH POPS OVER ONLY THE
NORTHEASTERN CWA THIS EVENING. SOME OF THE MODELS SHOW SIGNS OF
SOME WRAP AROUND SNOW SHOWERS TOWARDS MORNING SO KEPT THE 20 POPS
GOING IN THAT AREA AFTER MIDNIGHT.
ANOTHER ISSUE TONIGHT WILL BE WINDS. A FEW OF THE MODELS HAVE
VALUES APPROACHING WIND ADVISORY CRITERIA...PARTICULARLY OVER THE
DEVILS LAKE BASIN DURING THE 00Z TO 06Z TIME FRAME. ON ONE HAND
THERE WILL BE A FAIRLY TIGHT PRESSURE GRADIENT AND DECENT
SUBSIDENCE ON THE BACK SIDE OF THE DEPARTING LOW. ON THE OTHER
HAND...THE BEST WINDS ALOFT WILL BE COMING THROUGH DURING A PERIOD
WITH NOT MUCH MIXING...AND COLD AIR ADVECTION IS NOT AS STRONG AS
IT COULD BE. WILL MONITOR OBS DURING THE NEXT HOUR OR SO...BUT FOR
NOW WILL KEEP WINDS SUB ADVISORY CRITERIA BUT MENTION BLOWING SNOW
IN THE NORTHWEST PORTION OF THE CWA.
TOMORROW SHOULD BE FAIRLY QUIET AS UPPER RIDGING BRIEFLY BUILDS
INTO THE PLAINS. ANOTHER SFC LOW WILL DEVELOP OVER
SASKATCHEWAN...WITH SOUTHERLY WINDS AND WARM AIR ADVECTION KICKING
IN BY AFTERNOON. AIR MASS WILL CONTINUE TO BE FAIRLY MILD SO KEPT
HIGHS IN THE 20S. TEMPS SHOULD REMAIN FAIRLY WARM THROUGH
WEDNESDAY NIGHT AS SOUTHERLY WINDS PICK UP AS THE SFC TROUGH OVER
SOUTH CENTRAL CANADA DEEPENS. MODELS BRING IN SOME VERY WARM AIR
AT 850MB...UP CLOSE TO 10 C OVER THE SOUTHERN CWA. EVEN WITH A
FAIRLY LARGE INVERSION TEMPS WEDNESDAY NIGHT SHOULD STAY IN THE
UPPER TEENS TO LOW 20S.
THE NEXT QUESTION IS WHAT WILL HAPPEN WITH THE SYSTEMS COMING
THROUGH THURSDAY/FRIDAY. THE MODELS ALL ARE IN FAIRLY GOOD
AGREEMENT ON THE GENERAL PATTERN...BRINGING AN UPPER LOW FROM
TX/OK INTO THE UPPER MIDWEST AND THEN A LARGER TROUGH INTO THE
WESTERN PLAINS BY FRIDAY. HOWEVER...AS FAR AS SPEED AND WHEN
PRECIP STARTS MOVING INTO THE AREA MODEL SOLUTIONS ARE ALL OVER
THE PLACE. THE NAM IS FASTEST AND HAS PRECIP ENTERING THE
SOUTHEASTERN CWA BY THURSDAY AFTERNOON...WHILE THE GFS IS MUCH
SLOWER WITH THE SOUTHERN SYSTEM AND DOESN`T BRING PRECIP INTO THAT
AREA UNTIL LATE THURSDAY NIGHT INTO FRIDAY MORNING. THE NAM IS AN
OUTLIER BUT THE GFS SEEMS A BIT SLOW...SO LEANED MORE TOWARDS A
MIDDLE OF THE ROAD ECMWF/GEM SOLUTION. KEPT POPS VERY LOW BEFORE
00Z FRIDAY WITH INCREASING CHANCES THROUGHOUT THE NIGHT. WITH
FAIRLY WARM TEMPS IN PLACE AS THE SYSTEM ARRIVES...SOME
RAIN/FREEZING RAIN IS A POSSIBILITY IN THE SOUTHEASTERN CWA AS THE
PRECIP BEGINS. THINK THAT PRECIP SHOULD CHANGE OVER TO SNOW ON
FRIDAY AS A STRONG COLD FRONT BEGINS TO SLOWLY PUSH INTO THE AREA.
KEPT POPS IN THE HIGH CHANCE CATEGORY FOR FRIDAY GIVEN FAIRLY HIGH
UNCERTAINTY BUT LATER SHIFTS WILL HAVE TO REEVALUATE. FRIDAY
COULD SEE FALLING TEMPS IN THE AFTERNOON AS COLD AIR CONTINUES TO
PUSH INTO THE NORTHERN PLAINS.
LONG TERM (FRI NIGHT THRU TUE)...
MAJOR LONG RANGE GUIDANCE IN AGREEMENT DEPICTING SOUTHWEST FLOW AT
BEGINNING OF PERIOD MOVING A COLORADO SURFACE CYCLONE TO THE
VICINITY OF NORTHERN MINNESOTA/WISCONSIN EARLY SATURDAY. COLDER AIR
WILL BE IN PLACE IN THE WAKE OF THE EARLIER WARM UP...THIS IN TANDEM
WITH H500/H700 LOWS PROXIMAL TO THE RED RIVER VALLEY WOULD PORTEND A
MEASURABLE SNOW EVENT FROM LATE FRIDAY INTO THE FIRST PART OF
SATURDAY. LONG WAVE UPPER TROUGH LAGGING BEHIND THIS SYSTEM WILL
SWING THROUGH LATER IN THE WEEKEND BRINGING DOWN ARCTIC AIR AS
NORTHWEST FLOW ESTABLISHES ITSELF EARLY NEXT WEEK. LOWERED ALL BLEND
TEMPS JUST A TAD DURING THIS PERIOD IN AN ATTEMPT TO ACCOUNT FOR
SEVERAL INCHES OF PRISTINE SNOWFALL.
&&
.FGF WATCHES/WARNINGS/ADVISORIES...
ND...WIND ADVISORY UNTIL 6 AM CST EARLY THIS MORNING FOR NDZ006>008-
014>016-024-026>030-038-039-049-052>054.
MN...WIND ADVISORY UNTIL 6 AM CST EARLY THIS MORNING FOR MNZ001>005-
007-008-013>015-022-027-029-030-040.
&&
$$
DK
AREA FORECAST DISCUSSION
NWS PORTLAND OR
910 PM PST TUE JAN 8 2013
.SYNOPSIS....RAIN WILL CONTINUE ALONG THE NORTH COAST TONIGHT...WITH
MANY AREAS DRY. A COLD FRONT WILL DROP SE THROUGH THE REGION WED FOR
A ROUND OF VALLEY RAIN AND FAIRLY LOW SNOW LEVELS. A COLD UPPER
TROUGH WILL FOLLOW THE FRONT WED NIGHT AND THU FOR A CHANCE OF RAIN
AND SNOW SHOWERS. NORTHERLY FLOW ALOFTWILL KEEP A COOL AIR MASS IN
PLACE THROUGH THE REMAINDER OF THE WEEK WITH A CHANCE OF SNOW
SATURDAY...THEN A DRYING TREND ENSUES FOR NEXT WEEK.
&&
.SHORT TERM...A COLD FRONT IS STILL ON TRACK TO PUSH SOUTHEASTWARD
ACROSS THE AREA LATE TONIGHT INTO WEDNESDAY MORNING. MODELS AGREE
THIS FRONT WILL REMAIN PROGRESSIVE AS IT PUSHES THROUGH THE REGION.
THE HRRR SHOWS THE FRONT MOVING ACROSS THE PORTLAND METRO AREA AROUND
5AM...AND CLEARING THE CWA BY 11AM. THIS SHOULD RESULT IN SNOW LEVELS
BEHAVING...AND AS SUCH ONLY TWEAKED THE INHERITED FORECAST.
WINDS HAVE BEEN GUSTY ALONG THE COAST AND EXPECT THEM TO PICK UP JUST
A BIT MORE IN THE NEXT HOUR OR TWO BEFORE BEGINNING TO WANE FROM
NORTH TO SOUTH AROUND MIDNIGHT. THERE MAY BE AN ISOLATED GUST TO
60MPH ALONG AN EXPOSED HEADLAND...BUT WINDS ARE EXPECTED TO TOP OUT
IN THE 50 MPH RANGE FOR THE POPULATED AREAS.
A BURST OF WIND...GENERALLY GUSTS IN THE 35 TO 45 MPH RANGE WILL
LIKELY OCCUR IN THE WILLAMETTE VALLEY WITH FRONTAL PASSAGE LATE
TONIGHT.
WENT AHEAD AND INCLUDED THE LANE COUNTY CASCADES IN THE WINTER WX
ADVISORY AS THE LATEST MODEL RUNS SUGGEST THEY WILL SEE SIMILAR QPF
AS THEIR COUNTERPARTS TO THE NORTH.
HELD OFF ON ISSUING WINTER WX ADVISORIES FOR THE COAST RANGE AND
CASCADE FOOTHILLS DUE TO QPF DECREASING SUBSTANTIALLY BY THE TIME
SNOW LEVELS DIP BELOW 1500 FT. OROGRAPHICS BECOME INCREASINGLY LESS
FAVORABLE WEDNESDAY NIGHT INTO THURSDAY MORNING AS THE FLOW BECOMES
INCREASINGLY NORTHERLY.
ANY PASSING VORT MAX IN THE UNSTABLE AIR MASS COULD AID IN ORGANIZING
SHOWER ACTIVITY WEDNESDAY NIGHT INTO THURSDAY. TRYING TO PIN POINT
WHERE OR EVEN IF ONE WILL MOVE THROUGH THE AREA AT THIS POINT IS
SOMEWHAT A LOST CAUSE THIS FAR OUT. AS SUCH...KEPT POPS GENERALLY IN
THE 40 TO 60 RANGE DURING THIS TIME. SNOW LEVELS WILL BE LOW ENOUGH
THAT JUST ABOUT ANYONE COULD SEE SOME SNOW WITH A PASSING SHOWER BY
THURSDAY MORNING...BUT WIDESPREAD ACCUMULATING SNOW IS NOT EXPECTED
AT THIS TIME. /NEUMAN
.LONG TERM...FRIDAY AFTERNOON THROUGH MONDAY NIGHT... AN UPPER LEVEL
RIDGE REMAINS OFFSHORE WITH COOL NORTHERLY FLOW ALOFT MOVING OVER
THE PACIFIC NORTHWEST. THE MODERATE TO STRONG NORTHERLY FLOW IS AT
THE BACK EDGE OF AN EXITING COLD AIR MASS TO THE EAST WITH SHOWERS
ENDING FRIDAY AS A SYSTEM EXITS THE AREA. MODELS DIFFER IN THE
DETAILS OF A SHORT WAVE TROUGH MOVING OVER THE TOP OF THE RIDGE
EARLY IN THE WEEKEND AND TO THE OREGON/WASHINGTON BORDER BY LATE
SAT. DEPENDINGON THE DEVELOPMENT OF THE LOW ASSOCIATED WITH THE
TROUGH...IT COULD POTENTIALLY GENERATE ENOUGH CIRCULATION AND BRING
ENOUGH MOISTURE TO THE AREA TO DROP A LITTLE BIT OF SNOW OVER THE CWA
DURING THE WEEKEND. THE SYSTEM MOVES THROUGH THE AREA FAIRLY RAPIDLY.
CURRENTLY THE ECMWF IS THE MODEL SHOWING DEVELOPMENT OF THE LOW
PRESSURE SYSTEM THAT IS MORE PROMISING FOR AN INCH OR SNOW AT LOWER
ELEVATIONS...WHILE THE GFS TENDS TO REFLECT A MUCH WEAKER FEATURE AT
THE SURFACE. THE TREND TOWARD THE BEGINNING OF NEXT WEEK IS TOWARD
THE HIGH PROGRESSING VERY SLOWLY WESTWARD...AND BRINGING SLIGHTLY
WEAKER NORTHERLY FLOW TO THE AREA. KWELSON
&&
.AVIATION...CONDITIONS SHOULD REMAIN PRIMARILY VFR TONIGHT ACROSS
THE INTERIOR IN A WELL-MIXED MILD AIRMASS. THE MAIN EXCEPTIONS TO
THIS WILL BE IN THE SOUTH WILLAMETTE VALLEY AND NEAR THE COLUMBIA
RIVER WHERE MVFR STRATUS MAY FORM AFTER 08Z. EXPECT A MIX OF MVFR
AND IFR CONDITIONS ALONG THE COAST TONIGHT IN INCREASING RAIN.
THIS RAIN WILL PUSH INLAND EARLY WEDNESDAY MORNING AS A STRONG
COLD FRONT PUSHES ONSHORE FROM ABOUT 9Z TO 12Z ALONG THE COAST
AND 12Z TO 15Z INLAND. THEN CONDITIONS MAY IMPROVE BEHIND THE
FRONT IN THE AFTERNOON AS WE REMAIN IN A SHOWERY W/NW FLOW
PATTERN.
KPDX AND APPROACHES...EXPECT MAINLY VFR CONDITIONS OVERNIGHT WITH
DRY CONDITIONS AND SOUTHERLY WINDS. CONDITIONS WILL DETERIORATE
BETWEEN 12Z AND 15Z AS A STRONG COLD FRONT SPREADS RAIN INLAND.
SOME IMPROVEMENT MAY OCCUR LATER IN THE AFTERNOON BEHIND THE FRONT
AS WINDS TURN NORTHWESTERLY.
&&
.MARINE...GUSTY WINDS SHOULD CONTINUE THROUGH TONIGHT...WITH GUSTS
IN THE 35 TO 40 KT RANGE. LOCALIZED AREAS OF STRONGER WINDS ARE
POSSIBLE FROM TIME TO TIME THROUGH THIS EVENING IN THE NORTHERN
NEARSHORE WATERS. WINDS WILL TURN W/NW AND DROP OFF SOMEWHAT
BEHIND THE FRONT...ROUGHLY BETWEEN 09Z AND 12Z IN THE NORTHERN
WATERS AND 09Z TO 12Z IN THE SOUTHERN WATERS. WINDS MAY STRENGTHEN
AGAIN TO SMALL CRAFT ADVISORY LEVELS OVER THE OUTER WATERS LATER
WEDNESDAY IN A BREEZY POST-FRONTAL AIRMASS.
SEAS ARE CURRENTLY IN THE MID TEENS AND SHOULD HOLD ABOVE 10 FEET
THROUGH THE END OF THE WEEK. SEAS MAY SUBSIDE TO BELOW 10 FEET BY
THE WEEKEND.
&&
.PQR WATCHES/WARNINGS/ADVISORIES...
OR...WINTER WEATHER ADVISORY FROM 7 AM WEDNESDAY TO MIDNIGHT PST
WEDNESDAY NIGHT FOR CASCADES IN LANE COUNTY-NORTHERN OREGON
CASCADES.
WA...WINTER WEATHER ADVISORY FROM 4 AM WEDNESDAY TO MIDNIGHT PST
WEDNESDAY NIGHT FOR SOUTH WASHINGTON CASCADES.
PZ...GALE WARNING UNTIL 4 AM PST WEDNESDAY FOR COASTAL WATERS FROM
CAPE SHOALWATER WA TO CASCADE HEAD OR OUT 60 NM.
GALE WARNING UNTIL 7 AM PST WEDNESDAY FOR COASTAL WATERS FROM
CASCADE HEAD OR TO FLORENCE OR OUT 60 NM.
SMALL CRAFT ADVISORY FOR ROUGH COLUMBIA RIVER BAR UNTIL 4 PM PST
WEDNESDAY.
&&
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
1137 AM CST WED JAN 9 2013
.UPDATE...FOR AVIATION.
&&
.AVIATION...
18Z TAFS...WITH THE INFLUENCE OF A NORTHERN STREAM WAVE MOVING
EAST...RAINFALL WILL BE TAPERING OFF SOME THIS AFTERNOON. RAIN
WILL RAMP UP AGAIN TONIGHT AS A WARM FRONT MOVES IN FROM THE
SOUTH. PLENTY OF LOW LEVEL MOISTURE WILL REMAIN OVER THE AREA.
FOR CKV AND BNA...A COUPLE HOURS YET OF LINGERING SHOWERS AND
INTERMITTENT IFR CIGS...THEN CONDITIONS WILL IMPROVE TO MVFR WITH
SOME PERIODS OF VFR LATER TODAY. CONDITIONS WILL RAPIDLY
DETERIORATE TO IFR OVERNIGHT AS THE WARM FRONT APPROACHES.
CSV WILL SEE SOME IMPROVEMENT IN VSBY THIS AFTERNOON...BUT CIGS WILL
REMAIN LOW. RAIN AND LOWER CIGS/VSBYS WILL MOVE IN AGAIN TONIGHT.
13
&&
.PREV DISCUSSION... /ISSUED 1007 AM CST WED JAN 9 2013/
UPDATE...
12Z OHX SOUNDING DEPICTS A VERY MOIST ATMOSPHERE WITH A PWAT OF
1.32 INCHES...WHICH IS ABOVE THE 99TH PERCENTILE PWAT FOR JANUARY
AND NOT FAR FROM THE TYPICALLY OBSERVED MAXIMUM FOR THE MONTH.
LATEST RADAR IMAGERY SHOWS LIGHT TO MODERATE RAIN HAS OVERSPREAD
NEARLY THE ENTIRE CWA...WITH THE HEAVIEST RAIN AXIS FROM
LAWRENCEBURG TO LA VERGNE TO CELINA. RADAR ESTIMATES AND RAIN
GAUGE REPORTS INDICATE MANY LOCATIONS ALONG AND EITHER SIDE OF
THIS AXIS HAVE ALREADY SEEN OVER A HALF INCH OF RAIN TODAY. 12Z
GFS/NAM/ECMWF GUIDANCE SUGGESTS RAIN WILL TAPER OFF CONSIDERABLY
THIS AFTERNOON...BUT MOSAIC RADAR IMAGERY SHOWING PLUME OF
MOISTURE AND RAIN EXTENDING HUNDREDS OF MILES TO THE SOUTHWEST
INTO LOUISIANA AND THE WESTERN GULF OF MEXICO ARGUES RAIN WILL
CONTINUE THROUGH MUCH OF THE DAY. RECENT HRRR RUNS AGREE WITH
THIS AND DEPICT AREAS OF LIGHT TO MODERATE RAIN CONTINUING INTO
THE EVENING. WILL BUMP UP POPS INTO THE AFTERNOON HOURS BASED ON
RADAR TRENDS AND HRRR BEFORE DECREASING RAIN CHANCES LATER TODAY.
APPEARS WIDESPREAD CLOUDS AND PRECIPITATION MAY KEEP HIGH TEMPS
JUST UNDER CURRENT FORECAST AND LOWERED TEMPS A TAD IN SOME AREAS.
REST OF FORECAST LOOKS TO BE ON TRACK AND NO OTHER CHANGES WERE
MADE.
SS
PREV DISCUSSION... /ISSUED 711 AM CST WED JAN 9 2013/
UPDATE...
INCREASED POPS BEFORE NOON FOR ALL OF MIDDLE TENNESSEE. ALSO
INCREASED QPF TODAY BASED ON RAINFALL REPORTS OF 0.25 TO HALF AN
INCH THIS MORNING...WHICH AGREES WITH RADAR ESTIMATES. AS AN UPPER
LOW OVER EASTERN CANADA MOVES OFF TO THE EAST AND THE TEXAS LOW
MOVES NORTH THIS MOISTURE AXIS WILL BECOME MORE EAST TO WEST
ORIENTED THIS MORNING CAUSING A DECREASE IN POPS IN THE NORTHERN
HALF OF THE MID STATE AND KEEPING LIKELY POPS SOUTH OF I-40 THIS
AFTERNOON.
11
PREV DISCUSSION... /ISSUED 448 AM CST WED JAN 9 2013/
DISCUSSION...
RADAR INDICATES WIDESPREAD SHOWERS ENTERING THE AREA FROM THE
SOUTHWEST THIS MORNING WITH SCATTERED SHOWERS DEVELOPING ACROSS
MOST OF MIDDLE TN. EXPECT THAT RAINFALL WILL CONTINUE THROUGHOUT
THE DAY BEING MORE WIDESPREAD IN THE SOUTHERN AND WESTERN
COUNTIES. THIS SURGE OF MOISTURE IS BEING URGED UPWARD BY A CUTOFF
LOW OVER TEXAS THAT WILL GRADUALLY MOVE NORTH INTO OKLAHOMA TODAY.
WEDNESDAY NIGHT...HEAVIEST PRECIP IS EXPECTED TO REMAIN IN THE
WESTERN HALF OF MIDDLE TN. OVERCAST SKIES WILL SETTLE IN TODAY AND
TONIGHT KEEPING LOW TEMPERATURES MILD...AROUND 50 DEGREES.
THE LOW IS EXPECTED TO REMAIN WELL TO OUR WEST...MOVING FROM
OKLAHOMA TO THE MID MISSISSIPPI VALLEY ON THURSDAY. THEREFORE, POPS WILL
REMAIN HIGH IN THE WEST ON THURSDAY WITH ONLY CHANCE POPS AROUND
THE PLATEAU. THUNDERSTORM CHANCES REMAIN HIGHEST IN THE WEST AS
WELL AND ARE INTRODUCED INTO THE FORECAST AS EARLY AS 06Z
THURSDAY. A WARM FRONT IS EXPECTED TO LIFT NORTH THROUGH THE
MID STATE SOMETIME DURING THE MORNING HOURS ON THURSDAY ENCOURAGING
MORE THUNDERSTORM DEVELOPMENT ALONG WITH HEAVY SHOWERS.
SHOWERS AND THUNDERSTORMS WILL BE LESS LIKELY EARLY FRIDAY
MORNING PRIOR TO THE MAIN MOISTURE AXIS PUSHING THROUGH. AN
ENHANCED LOW LEVEL JET AND THE PASSAGE OF ANOTHER BAND OF DEEP
MOISTURE LATER IN THE MORNING COULD INFLUENCE SOME STORMS TO
BECOME STRONG...WITH GUSTY WINDS, HEAVY DOWNPOURS, AND SMALL
HAIL. WIDESPREAD RAINFALL AMOUNTS OF 1 INCH ARE LIKELY WITH
LOCALIZED AMOUNTS AROUND 2 TO 3 INCHES POSSIBLE AT THE END OF THE
SHORT TERM.
FRIDAY AFTERNOON AND EVENING CLOUDS ARE EXPECTED TO THIN OUT, BUT
NOT DISAPPEAR AS THE LOW PRESSURE SYSTEM MOVES OFF TO THE
NORTHEAST. HIGH TEMPERATURES ON FRIDAY COULD REACH 65 DEGREES
ALONG THE PLATEAU AND NEAR 70 ELSEWHERE...VERY CLOSE TO THE DAILY
RECORD OF 72 IN NASHVILLE AND 64 IN CROSSVILLE...HOWEVER THIS IS
VERY DEPENDENT ON THE AMOUNT OF CLOUD COVER AND HOW QUICKLY IT
PARTIALLY CLEARS OUT AFTER THE BAND OF MOISTURE.
THIS WEEKEND QUICKLY BECOMES A RAINY ONE WITH THE NEXT SYSTEM
PUSHING INTO THE MID STATE SATURDAY MORNING AND LINGERING THROUGH
THE END OF THE FORECAST PERIOD. MODELS AGREE THAT A BAND OF DEEP
MOISTURE WILL SET UP ACROSS THE TENNESSEE AND OHIO VALLEYS AS A
STRONG RIDGE STAYS IN PLACE OFF THE EAST COAST. STRONG UPPER LEVEL
WINDS FROM THE SOUTHWEST WILL BRING DEEP SUBTROPICAL MOISTURE INTO
THE SOUTHEAST. PWAT VALUES STILL LOOK EXCEPTIONALLY HIGH FOR THIS
TIME OF THE YEAR..AROUND 1.5 INCHES...THROUGH AT LEAST MONDAY NIGHT.
THE DIFFERENCES IN THE BOUNDARY LOCATION WILL DETERMINE WHERE THE
HEAVIEST RAINFALL TOTALS DEVELOP AND ALSO THE TEMPERATURES IN THE
LONG TERM. COLDER AIR...NEAR SEASONAL NORMS...WILL FILE IN BEHIND
THE BOUNDARY BY MID WEEK NEXT WEEK.
11
&&
.OHX WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS NASHVILLE TN
1007 AM CST WED JAN 9 2013
.UPDATE...
12Z OHX SOUNDING DEPICTS A VERY MOIST ATMOSPHERE WITH A PWAT OF
1.32 INCHES...WHICH IS ABOVE THE 99TH PERCENTILE PWAT FOR JANUARY
AND NOT FAR FROM THE TYPICALLY OBSERVED MAXIMUM FOR THE MONTH.
LATEST RADAR IMAGERY SHOWS LIGHT TO MODERATE RAIN HAS OVERSPREAD
NEARLY THE ENTIRE CWA...WITH THE HEAVIEST RAIN AXIS FROM
LAWRENCEBURG TO LA VERGNE TO CELINA. RADAR ESTIMATES AND RAIN
GAUGE REPORTS INDICATE MANY LOCATIONS ALONG AND EITHER SIDE OF
THIS AXIS HAVE ALREADY SEEN OVER A HALF INCH OF RAIN TODAY. 12Z
GFS/NAM/ECMWF GUIDANCE SUGGESTS RAIN WILL TAPER OFF CONSIDERABLY
THIS AFTERNOON...BUT MOSAIC RADAR IMAGERY SHOWING PLUME OF
MOISTURE AND RAIN EXTENDING HUNDREDS OF MILES TO THE SOUTHWEST
INTO LOUISIANA AND THE WESTERN GULF OF MEXICO ARGUES RAIN WILL
CONTINUE THROUGH MUCH OF THE DAY. RECENT HRRR RUNS AGREE WITH
THIS AND DEPICT AREAS OF LIGHT TO MODERATE RAIN CONTINUING INTO
THE EVENING. WILL BUMP UP POPS INTO THE AFTERNOON HOURS BASED ON
RADAR TRENDS AND HRRR BEFORE DECREASING RAIN CHANCES LATER TODAY.
APPEARS WIDESPREAD CLOUDS AND PRECIPITATION MAY KEEP HIGH TEMPS
JUST UNDER CURRENT FORECAST AND LOWERED TEMPS A TAD IN SOME AREAS.
REST OF FORECAST LOOKS TO BE ON TRACK AND NO OTHER CHANGES WERE
MADE.
&&
.PREV DISCUSSION... /ISSUED 711 AM CST WED JAN 9 2013/
UPDATE...
INCREASED POPS BEFORE NOON FOR ALL OF MIDDLE TENNESSEE. ALSO
INCREASED QPF TODAY BASED ON RAINFALL REPORTS OF 0.25 TO HALF AN
INCH THIS MORNING...WHICH AGREES WITH RADAR ESTIMATES. AS AN UPPER
LOW OVER EASTERN CANADA MOVES OFF TO THE EAST AND THE TEXAS LOW
MOVES NORTH THIS MOISTURE AXIS WILL BECOME MORE EAST TO WEST
ORIENTED THIS MORNING CAUSING A DECREASE IN POPS IN THE NORTHERN
HALF OF THE MID STATE AND KEEPING LIKELY POPS SOUTH OF I-40 THIS
AFTERNOON.
PREV DISCUSSION... /ISSUED 448 AM CST WED JAN 9 2013/
DISCUSSION...
RADAR INDICATES WIDESPREAD SHOWERS ENTERING THE AREA FROM THE
SOUTHWEST THIS MORNING WITH SCATTERED SHOWERS DEVELOPING ACROSS
MOST OF MIDDLE TN. EXPECT THAT RAINFALL WILL CONTINUE THROUGHOUT
THE DAY BEING MORE WIDESPREAD IN THE SOUTHERN AND WESTERN
COUNTIES. THIS SURGE OF MOISTURE IS BEING URGED UPWARD BY A CUTOFF
LOW OVER TEXAS THAT WILL GRADUALLY MOVE NORTH INTO OKLAHOMA TODAY.
WEDNESDAY NIGHT...HEAVIEST PRECIP IS EXPECTED TO REMAIN IN THE
WESTERN HALF OF MIDDLE TN. OVERCAST SKIES WILL SETTLE IN TODAY AND
TONIGHT KEEPING LOW TEMPERATURES MILD...AROUND 50 DEGREES.
THE LOW IS EXPECTED TO REMAIN WELL TO OUR WEST...MOVING FROM
OKLAHOMA TO THE MID MISSISSIPPI VALLEY ON THURSDAY. THEREFORE, POPS WILL
REMAIN HIGH IN THE WEST ON THURSDAY WITH ONLY CHANCE POPS AROUND
THE PLATEAU. THUNDERSTORM CHANCES REMAIN HIGHEST IN THE WEST AS
WELL AND ARE INTRODUCED INTO THE FORECAST AS EARLY AS 06Z
THURSDAY. A WARM FRONT IS EXPECTED TO LIFT NORTH THROUGH THE
MID STATE SOMETIME DURING THE MORNING HOURS ON THURSDAY ENCOURAGING
MORE THUNDERSTORM DEVELOPMENT ALONG WITH HEAVY SHOWERS.
SHOWERS AND THUNDERSTORMS WILL BE LESS LIKELY EARLY FRIDAY
MORNING PRIOR TO THE MAIN MOISTURE AXIS PUSHING THROUGH. AN
ENHANCED LOW LEVEL JET AND THE PASSAGE OF ANOTHER BAND OF DEEP
MOISTURE LATER IN THE MORNING COULD INFLUENCE SOME STORMS TO
BECOME STRONG...WITH GUSTY WINDS, HEAVY DOWNPOURS, AND SMALL
HAIL. WIDESPREAD RAINFALL AMOUNTS OF 1 INCH ARE LIKELY WITH
LOCALIZED AMOUNTS AROUND 2 TO 3 INCHES POSSIBLE AT THE END OF THE
SHORT TERM.
FRIDAY AFTERNOON AND EVENING CLOUDS ARE EXPECTED TO THIN OUT, BUT
NOT DISAPPEAR AS THE LOW PRESSURE SYSTEM MOVES OFF TO THE
NORTHEAST. HIGH TEMPERATURES ON FRIDAY COULD REACH 65 DEGREES
ALONG THE PLATEAU AND NEAR 70 ELSEWHERE...VERY CLOSE TO THE DAILY
RECORD OF 72 IN NASHVILLE AND 64 IN CROSSVILLE...HOWEVER THIS IS
VERY DEPENDENT ON THE AMOUNT OF CLOUD COVER AND HOW QUICKLY IT
PARTIALLY CLEARS OUT AFTER THE BAND OF MOISTURE.
THIS WEEKEND QUICKLY BECOMES A RAINY ONE WITH THE NEXT SYSTEM
PUSHING INTO THE MID STATE SATURDAY MORNING AND LINGERING THROUGH
THE END OF THE FORECAST PERIOD. MODELS AGREE THAT A BAND OF DEEP
MOISTURE WILL SET UP ACROSS THE TENNESSEE AND OHIO VALLEYS AS A
STRONG RIDGE STAYS IN PLACE OFF THE EAST COAST. STRONG UPPER LEVEL
WINDS FROM THE SOUTHWEST WILL BRING DEEP SUBTROPICAL MOISTURE INTO
THE SOUTHEAST. PWAT VALUES STILL LOOK EXCEPTIONALLY HIGH FOR THIS
TIME OF THE YEAR..AROUND 1.5 INCHES...THROUGH AT LEAST MONDAY NIGHT.
THE DIFFERENCES IN THE BOUNDARY LOCATION WILL DETERMINE WHERE THE
HEAVIEST RAINFALL TOTALS DEVELOP AND ALSO THE TEMPERATURES IN THE
LONG TERM. COLDER AIR...NEAR SEASONAL NORMS...WILL FILE IN BEHIND
THE BOUNDARY BY MID WEEK NEXT WEEK.
&&
.OHX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHAMBURGER
AREA FORECAST DISCUSSION
NWS MORRISTOWN TN
942 AM EST WED JAN 9 2013
.DISCUSSION...RAIN GRADUALLY SPREADING NE THIS MORNING WITH SOME
LIGHT ACCUMULATIONS MAINLY NOTED OVER THE WRN THIRD OF THE FORECAST
AREA. LATEST RUC MODEL RUN SPREADS THESE LIGHT ACCUMULATIONS INTO
MUCH OF THE TN VALLEY AND INTO LEE/WISE COUNTIES OF SW VA OVER THE
NEXT FEW HOURS. PLAN TO UPDATE THE FORECAST GRIDS AND PRODUCTS
SHORTLY WITH AN INCREASE IN POPS FOR THOSE AREAS. PROBABLY WILL STAY
WITH NO MORE THAN HIGH CHANCE POPS FOR THE FAR NE AREAS.
12Z OHX SOUNDING HAD VERY HIGH PRECIPITABLE WATER VALUE OF 1.32
INCHES...AND THIS MOISTURE WILL BE WORKING EASTWARD THROUGH THE
WEEKEND. STAY TUNED FOR SOME WET WEATHER INTO THE MIDDLE OF NEXT
WEEK.
&&
.PRELIMINARY POINT TEMPS/POPS...
CHATTANOOGA AIRPORT, TN 59 48 66 55 69 / 60 50 40 60 60
KNOXVILLE MCGHEE TYSON AIRPORT, TN 58 46 66 51 66 / 40 40 40 60 60
OAK RIDGE, TN 57 46 65 52 67 / 40 40 40 50 60
TRI CITIES AIRPORT, TN 55 43 64 45 64 / 30 20 30 30 30
&&
.MRX WATCHES/WARNINGS/ADVISORIES...
NC...NONE.
TN...NONE.
VA...NONE.
&&
$$
TG
AREA FORECAST DISCUSSION
NWS SAN ANGELO TX
1133 PM CST TUE JAN 8 2013
.UPDATE...
THE LATEST SATELLITE AND WSR-88D DATA INDICATE THE UPPER-LEVEL
SYSTEM REMAINS POSITIONED FOR MAINLY SHOWERS TO CONTINUE ACROSS
WEST CENTRAL TEXAS FOR THE REMAINDER OF TONIGHT. SO FAR...WE HAVE
NOT RECEIVED THE WIDESPREAD HIGHER-AMOUNTS RAINFALL WE WERE
ANTICIPATING. HOWEVER...THE LATEST RUC DATA INDICATE THE AREA OF
PRECIPITATION WILL CONTINUE TO EXPAND FARTHER NORTH ACROSS WEST
CENTRAL TEXAS FOR THE REMAINDER OF TONIGHT. GIVEN PAST TRENDS AND
NEW MODEL DATA...I DECIDED TO CONTINUE CATEGORICAL POPS ACROSS THE
BOARD FOR THE REMAINDER OF TONIGHT. I DID MAKE A COUPLE CHANGES.
I REPLACED THE RAIN SHOWERS PLUS IN OUR WEATHER GRIDS WITH RAIN
SHOWERS MODERATE. THIS REMOVED THE LOCALLY HEAVY RAINFALL ZONE
FORECAST PRODUCT WORDING FOR TONIGHT. PLUS...I REMOVED
THUNDERSTORMS FROM ALL BUT THE NORTHWEST HILL COUNTRY AND SOME OF
THE HEARTLAND FOR THE REMAINDER OF TONIGHT. WITH WATER VAPOR
IMAGERY INDICATING A BETTER DEFINED DEFORMATION ZONE DEVELOPING
OVER WEST CENTRAL TEXAS...THE THUNDERSTORM POTENTIAL HAS DECREASED
FOR MOST OF WEST CENTRAL TEXAS FOR TONIGHT. THE LATEST ZONE
FORECAST AND POINT FORECAST MATRICES PRODUCTS REFLECT THESE
GRIDS CHANGES.
HUBER
&&
.PREV DISCUSSION... /ISSUED 509 PM CST TUE JAN 8 2013/
DISCUSSION...
SEE 00Z AVIATION DISCUSSION BELOW.
AVIATION...
IFR TO LIFR CONDITIONS WILL PREVAIL OVER THE NEXT 24 HOURS. HAVE
ONLY INCLUDED RAIN AND LIGHT RAIN IN THE TAFS WITH NO MENTION OF
THUNDER. ANY THUNDERSTORMS LOOK TO BE ISOLATED AND IT IS UNCERTAIN
THAT ANY WILL IMPACT ANY TERMINALS. THE BEST CHANCES WOULD BE AT
JUNCTION AND BRADY. WILL CONTINUE TO MONITOR AND WILL AMEND TAFS
AS NEEDED. EXPECTING WINDS OUT OF THE NORTHEAST AROUND 10 KNOTS.
21
PREV DISCUSSION... /ISSUED 330 PM CST TUE JAN 8 2013/
SHORT TERM...
THE MAIN FORECAST PROBLEM FOR THE SHORT TERM IS THE CONTINUING RAIN
THREAT ACROSS WEST CENTRAL TEXAS. LIGHT RAIN HAS FALLEN ACROSS THE
AREA THROUGH MUCH OF THIS MORNING AND MORE IS DEVELOPING SOUTH OF
THE AREA. BEST CHANCES FOR RAIN LOOKS TO BE THIS EVENING AND
OVERNIGHT TONIGHT AS THE LOW OVER NORTHERN MEXICO PUSHES FURTHER
INTO WEST TEXAS. HPC STANDARD ANOMALIES ARE STILL SHOWING A MODEL
CONSENSUS OF 1 TO 2 STANDARD DEVIATIONS ABOVE NORMAL FOR
PRECIPITABLE WATER. FOR QPF I USED THE HPC GUIDANCE AS IT IS IN GOOD
AGREEMENT WITH BOTH THE NAM AND THE ECMWF. I HAVE LITTLE CONFIDENCE
IN THE GFS SOLUTION AS IT IS MUCH HIGHER THAN THE NAM OR ECMWF AND
THE GEFS MEAN PRECIP IS DOWN PLAYING THESE HIGHER AMOUNTS. RAIN MAY
BE HEAVY AT TIME REDUCING VISIBILITIES TO LESS THAN ONE MILE. MOST
AREAS CAN EXPECT 1 TO 2 INCHES OF RAIN AND SOME LOCATIONS MAY SEE
UP TO 3 INCHES. TEMPERATURES LOOK TO STAY IN THE MID 40S...MOSTLY
DUE TO THE THE OVERCAST SKIES THAT ARE EXPECTED. HIGHS WILL BE
LITTLE WARMER TOMORROW AS THE RAIN MOVES OUT BUT ONLY EXPECT A
COUPLE OF DEGREES MORE.
13
LONG TERM...
THE UPPER LEVEL LOW WILL BE MOVING FROM NORTHERN MEXICO NORTHEAST
OVER THE SOUTHERN FORECAST AREA BY THURSDAY EVENING WITH THE GFS
AND ECMWF FAIRLY CLOSE IN TIMING AND THE NAM A LITTLE FASTER. HAVE
GONE WITH A BLEND OF THE TIMING GRADUATING RAIN CHANCES FROM 30
POPS OVER THE SOUTHERN CWA TO 70S POPS OVER THE NORTHERN CWA
THROUGH MIDNIGHT WEDNESDAY WITH THE CHANCE OF SHOWERS ENDING FROM
THE SOUTH TO THE NORTH THROUGH WEDNESDAY NIGHT. HAVE KEPT A SLIGHT
CHANCE OF RESIDUAL SHOWERS OVER THE BIG COUNTRY THURSDAY MORNING.
THE UPPER LEVEL LOW WILL OPEN AS IT MOVES NORTHEAST AND MERGES WITH
THE SOUTHWEST FLOW ALOFT BY THE END OF THE WEEK. THE FORECAST AREA
WILL REMAIN UNDER A SOUTHWEST FLOW ALOFT AS ANOTHER UPPER TROUGH
DIGS OVER THE WESTERN STATES. THE UPPER WESTERN TROUGH WILL BE SLOW
TO MOVE EAST WITH THE TROUGH AXIS WEST OF THE FORECAST AREA
THROUGH THE END OF THE EXTENDED. THE NEXT COLD FRONTAL PASSAGE
WILL BE SATURDAY WITH THE ECMWF AND GFS SHOWING A SLIGHT CHANCE OF
ASSOCIATED RAINFALL OVER THE EASTERN CWA SATURDAY INTO SUNDAY.
WILL LEAVE THE FORECAST DRY FOR NOW AND AWAIT ADDITIONAL MODEL
RUNS BEFORE INCLUDING ANY RAINFALL.
WILL SEE A NICE WARM-UP THURSDAY AND FRIDAY IN ADVANCE OF THE NEXT
COLD FRONT WITH HIGHS ON THURSDAY IN THE 60S AND IN THE UPPER 60S
TO THE LOWER 70S ON FRIDAY. BY THE BEGINNING OF THE COMING WEEK
POSTFRONTAL AFTERNOON HIGHS WILL BE MOSTLY IN THE 40S. MORNING
LOWS WILL COOL INTO THE 20S BY SUNDAY AND WILL REMAIN IN THE 20S
THROUGH THE MIDDLE OF THE COMING WEEK.
&&
.PRELIMINARY POINT TEMPS/POPS...
ABILENE 45 50 37 58 41 / 90 90 50 20 5
SAN ANGELO 44 48 37 62 38 / 90 80 40 10 5
JUNCTION 45 54 38 66 38 / 100 80 30 10 0
&&
.SJT WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
HUBER
AREA FORECAST DISCUSSION...UPDATED
NWS MILWAUKEE/SULLIVAN WI
827 PM CST THU JAN 10 2013
.UPDATE...
THE INITIAL SURGE OF MOISTURE PUSHED INTO SOUTHERN WISCONSIN LATE IN
THE AFTERNOON WITH 850MB WARM AIR ADVECTION AND 700-400MB
DIFFERENTIAL VORTICITY ADVECTION. INITIAL AMOUNTS WERE VERY
LIGHT...BUT HELPED TO MOISTEN UP THE LOWER LEVELS. RAIN SHOWERS HAVE
BEEN GRADUALLY FILLING IN ACROSS SOUTHERN WI BEHIND THAT FIRST
ROUND. CLOUD BASES DROPPED RAPIDLY AND VISIBILITIES ARE ON THEIR
WAY DOWN...LESS THAN 5 MILES IN MOST AREAS. NOW WE AWAIT AN AREA
OF WIDESPREAD RAIN IN CENTRAL IL TO SPREAD INTO SOUTHERN WI
BETWEEN 03Z AND 05Z. THIS IS ASSOCIATED WITH ANOTHER WAVE OF
DIFFERENTIAL VORTICITY ADVECTION AND DECENT Q-VECTOR CONVERGENCE.
THE 23Z HRRR MODEL SEEMS TO HAVE A GOOD HANDLE ON THE PRECIP
COVERAGE AT THIS TIME. IT SHOWS THE PRECIP DIMINISHING SIGNIFICANTLY
AFTER 06Z IN ALL OF THE CWA EXCEPT FAR SOUTHEAST. THE SOUTHEAST
PRECIP SHOULD DIMINISH AFTER 09Z.
AREAS OF DENSE FOG WILL DEVELOP AS THE PRECIP ENDS. EXPECTING
VISIBILITIES TO DROP BELOW A HALF MILE GENERALLY FROM SOUTHWEST TO
EAST ACROSS THE FORECAST AREA BETWEEN 06Z AND 09Z. WILL KEEP THE
DENSE FOG ADVISORY WITH THE BEGINNING TIME OF 09Z. THERE IS STILL A
RISK FOR SOUTHEAST WI TO DEVELOP DENSE FOG EARLY FRI MORNING. THE
HRRR HAS BEEN DROPPING VISIBILITY TO LESS THAN A QUARTER MILE IN
SOUTHEAST WI RIGHT AFTER THE RAIN ENDS THROUGH 13Z FRI. PER
COORDINATION WITH THE CHICAGO NWS...WILL NOT ADD THIS AREA TO THE
DENSE FOG ADVISORY AT THIS TIME GIVEN THE LOWER CONFIDENCE.
&&
.AVIATION/06Z TAFS/...
CEILINGS AND VISIBILITIES ARE ON THEIR WAY DOWN QUICKLY THIS
EVENING. EXPECT DENSE FOG TO DEVELOP IN MADISON JUST AS THE RAIN
ENDS...AND THIS COULD BE AS EARLY AS 06Z. THE HRRR MODEL HAS BEEN
SHOWING VSBY LESS THAN A QUARTER MILE BETWEEN 09Z AND 13Z IN
SOUTHEAST WISCONSIN IN THE LAST FEW FORECAST RUNS. STILL LOWER
CONFIDENCE ON THAT SCENARIO GIVEN THE LACK OF SNOW...SO LEFT THE
DENSE FOG OUT OF THE EASTERN TAF SITES.
CIGS AND VSBYS WILL BE VERY SLOW TO IMPROVE ON FRI.
&&
.PREV DISCUSSION... /ISSUED 318 PM CST THU JAN 10 2013/
AVIATION/00Z TAFS/...VFR CONDITIONS THIS AFTERNOON WILL GIVE WAY TO
RAIN...FOG...DRIZZLE TONIGHT AND FRI AS LOW PRESSURE MOVES FROM
THE LOWER MS RIVER VALLEY THROUGH WI. RELATIVELY MILD AND MOIST
AIR WILL FLOW OVER A MELTING SNOW COVER AND FROZEN GROUND
RESULTING IN ADVECTION FOG. CIGS WILL DROP TO 200-400 FEET AND
VSBYS TO 1 MILE BY MID TO LATE EVENING WITH DENSE FOG FORMING OVER
SOUTH CENTRAL AND EAST CENTRAL WI AFTER THE MAIN RAIN AREA
DEPARTS. THIS WILL BE AFTER 08Z AND COULD THEN LAST THROUGH ALL
FRI MORNING WITH FOG AND VSBYS IMPROVING GRADUALLY FRI AFT. THE SE
WI TAF SITES WILL SEE VSBYS DROP TO 1/2-1 MILE WITH A SMALLER
POTENTIAL FOR DENSE FOG GIVEN THE LACK OF SNOW COVER.
MARINE...A SMALL CRAFT ADVISORY IS IN EFFECT FROM 6 PM UNTIL NOON.
BREEZY SELY WINDS WILL BUILD HIGH WAVES FOR TNT INTO FRI AM AHEAD OF
THE APPROACHING LOW PRESSURE. THE WINDS AND WAVES WILL DIMINISH BY
NOON FRIDAY AS THE LOW MOVES AWAY. FOG IS ALSO EXPECTED OVER THE
WATERS OF LAKE MICHIGAN AS A MILD AND MOIST AIRMASS FLOWS OVER THE
COLD WATERS OF LAKE MI. THERE IS SOME POTENTIAL FOR DENSE FOG
ESPECIALLY NORTH OF PORT WASHINGTON DURING FRI AM.
ANOTHER SMALL CRAFT ADVISORY MAY BE NEEDED FRI NT AND SAT AS STRONG
LOW PRESSURE TRACKS FROM MN TO JAMES BAY CANADA. BREEZY SOUTH WINDS
SHIFTING TO WEST WINDS ARE POSSIBLE.
&&
.MKX WATCHES/WARNINGS/ADVISORIES...
WI...DENSE FOG ADVISORY FROM 3 AM TO NOON CST FRIDAY FOR WIZ046-047-
051-052-056>059-062>064-067>069.
LM...SMALL CRAFT ADVISORY UNTIL NOON CST FRIDAY FOR LMZ643>646.
&&
$$
UPDATE...MRC
TONIGHT/FRIDAY AND AVIATION/MARINE...GEHRING
FRIDAY NIGHT THROUGH THURSDAY...COLLAR
AREA FORECAST DISCUSSION
NWS COLUMBIA SC
258 AM EST FRI JAN 11 2013
.SYNOPSIS...
A WEAK WARM FRONT WILL SHIFT NORTH OF THE FORECAST AREA TODAY.
TEMPERATURES THIS WEEKEND INTO EARLY NEXT WEEK WILL BE WELL ABOVE
NORMAL AS AN UPPER RIDGE REMAINS OVER THE AREA. THE CHANCE FOR
RAIN INCREASES DURING THE MIDDLE OF NEXT WEEK AS A SLOW MOVING
COLD FRONT PUSHES INTO THE AREA.
&&
.NEAR TERM /THROUGH TODAY/...
CONVERGENCE ASSOCIATED WITH THE WARM FRONT HAS RESULTED IN
WIDESPREAD LOW CLOUDINESS AND FOG. THE FOG MAY BECOME DENSE. A DENSE
FOG ADVISORY MAY BE NEEDED. ISENTROPIC LIFT AND A MID-LEVEL
SHORTWAVE TROUGH SUPPORTS RAIN. THE LATEST RAP SHOWS THE MOST LIFT
AND MOISTURE ASSOCIATED WITH THE TROUGH IN THE NORTH AND WEST
SECTIONS 12Z TO 15Z THIS MORNING. FORECASTED HIGHER POPS DURING THIS
TIME. OTHERWISE...EXPECT MOISTURE WILL BE SHALLOW AND ISENTROPIC
LIFT WEAK SUPPORTING VERY LOW POPS. AS THE WARM FRONT LIFTS NORTH OF
THE AREA EXPECT BREAKS IN THE CLOUDINESS WILL OCCUR LATER TODAY. IT
WILL BE ANOTHER WARM DAY. USED THE GFS AND NAM MOS AND FORECASTED
HIGHS IN THE UPPER 60S NORTH TO MIDDLE AND UPPER 70S SOUTH.
&&
.SHORT TERM /TONIGHT THROUGH SUNDAY NIGHT/...
THE UPPER RIDGE WILL BUILD BACK OVER THE FORECAST AREA AND UP THE
EAST COAST TONIGHT THROUGH SATURDAY AS THE WEST COAST TROUGH
DEEPENS ONCE AGAIN. SURFACE HIGH PRESSURE WILL BE CENTERED OFF THE
CAROLINA COAST AND PROVIDE A WARM SOUTHWESTERLY BOUNDARY LAYER
FLOW. THE MAIN PWAT AXIS AND MOISTURE FLUX TRANSPORT WILL REMAIN
OVER THE MISSISSIPPI AND TENNESSEE VALLEYS THROUGH THE PERIOD AND
EXPECT A GENERALLY DRY FORECAST OVER THE MIDLANDS AND CSRA.
TEMPERATURES WILL BE THE MAIN INTEREST THIS WEEKEND AS LATE SPRING
LIKE TEMPERATURES ARE EXPECTED WITH MAX TEMPS SOME 15-20 DEGREES
ABOVE NORMAL. RECORD HIGH TEMPERATURES WILL BE IN JEOPARDY OF
FALLING BOTH SATURDAY AND SUNDAY ACROSS THE REGION WHILE OVERNIGHT
LOW TEMPERATURES ARE FORECAST TO BE IN THE MID TO UPPER 50S WHICH
IS AROUND WHAT OUR NORMAL HIGH TEMPERATURES ARE THIS TIME OF YEAR.
&&
.LONG TERM /MONDAY THROUGH THURSDAY/...
THE EXTENDED FORECAST FEATURES A HIGHLY AMPLIFIED UPPER PATTERN
EARLY NEXT WEEK WITH A LARGE POSITIVELY TILTED TROUGH ACROSS MUCH
OF THE WESTERN TWO THIRDS OF THE COUNTRY WITH THE UPPER RIDGE AXIS
SHIFTED WELL OFF THE EAST COAST. MONDAY SHOULD BE DRY FOR MOST OF
THE AREA BUT SOME SHOWERS WILL BE POSSIBLE IN THE NORTHERN AND
WESTERN MIDLANDS MONDAY AFTERNOON AS A SLOW MOVING COLD FRONT
WHICH WILL BE FOCUSING FLOODING RAINS OVER THE MISSISSIPPI AND
TENNESSEE VALLEYS DRIFTS SLOWLY EASTWARD TOWARDS THE FORECAST
AREA. TEMPERATURES ON MONDAY WILL AGAIN BE WELL ABOVE NORMAL IN
THE 70S AND LOWS MONDAY NIGHT WILL BE MILD IN THE MID TO UPPER
50S.
AS NORTHERN STREAM ENERGY DROPS INTO THE LONGWAVE TROUGH BY
TUESDAY...HEIGHTS WILL FALL OVER THE FORECAST AREA AND THE FRONT
WILL GRADUALLY MOVE INTO THE AREA. THE FRONT WILL BE SLOW TO PUSH
ACROSS THE REGION DUE TO ITS NEARLY PARALLEL ORIENTATION TO THE
UPPER FLOW AND THIS WILL BRING INCREASED CHANCES OF RAIN TUESDAY
AND WEDNESDAY WITH THE FRONTAL BOUNDARY NEARBY. HAVE INCREASED
POPS A BIT INTO THE HIGHER CHANCE RANGE TUESDAY THROUGH
WEDNESDAY...AND THEY MAY NEED TO BE INCREASED FURTHER ON LATER
SHIFTS...AS MOISTURE TRANSPORT AND PWAT VALUES INCREASE WITHIN THE
FRONTAL ZONE. TEMPERATURES WILL BEGIN TO COOL A BIT BY MID WEEK
BUT WILL LIKELY EXHIBIT A STRONG GRADIENT ACROSS THE FORECAST AREA
ON TUESDAY FROM SOUTHEAST TO NORTHWEST. CONFIDENCE LOWERS LATE IN
THE LONG TERM AS MODEL CONSISTENCY DIMINISHES.
&&
.AVIATION /07Z FRIDAY THROUGH TUESDAY/...
CONVERGENCE ASSOCIATED WITH THE WARM FRONT HAS RESULTED IN STRATUS
AND FOG THIS MORNING. AS THE FRONT LIFTS NORTH OF THE AREA
IMPROVEMENT SHOULD OCCUR. THE GFS AND NAM MOS WERE IN GOOD
AGREEMENT MAINTAINING IFR CONDITIONS THROUGH THIS MORNING...WITH
MVFR AND VFR CEILINGS DEVELOPING THIS AFTERNOON.
EXTENDED AVIATION OUTLOOK...THERE WILL LIKELY BE SUFFICIENT
LOW-LEVEL MOISTURE FOR WIDESPREAD MVFR OR IFR CEILINGS AND
VISIBILITIES DURING THE EARLY MORNING HOURS SATURDAY THROUGH
MONDAY. RESTRICTIONS ASSOCIATED WITH A FRONTAL SYSTEM MAY OCCUR
TUESDAY.
&&
.CLIMATE...
RECORD HIGH TEMPERATURE INFORMATION FOR JANUARY 12/13/14:
SATURDAY JAN 12TH RECORD HIGHS...
CAE: 77 (1916)
AGS: 78 (1916)
SUNDAY JAN 13TH RECORD HIGHS...
CAE: 77 (2005)
AGS: 79 (2005)
MONDAY JAN 14TH RECORD HIGHS...
CAE: 80 (1932)
AGS: 84 (1932)
&&
.CAE WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
GA...NONE.
&&
$$
SYNOPSIS...RJL/HC
NEAR TERM...RJL
SHORT TERM...HC
LONG TERM...HC
AVIATION...RJL
CLIMATE...HC
AREA FORECAST DISCUSSION
NWS DES MOINES IA
315 AM CST FRI JAN 11 2013
.SHORT TERM /TODAY/...
THE UPPER LEVEL LOW THAT WAS MOVING NORTHEAST ACROSS MISSOURI WILL
BE IN THE GREAT LAKES REGION LATER THIS MORNING. A LONG WAVE TROUGH
WILL SET UP OVER THE INTERMOUNTAIN WEST PROVIDING A DEEP SOUTHWEST
FLOW ALOFT OVER IOWA. IN ADDITION A SURFACE LOW WILL SET UP JUST TO THE
WEST OF IOWA. THE GRADIENT WILL TIGHTEN OVER CENTRAL IOWA LATER
THIS MORNING AND ESPECIALLY THIS AFTERNOON AND CREATE BREEZY
CONDITIONS AS THE SOUTHERLY FLOW ALSO ADVECTS IN SOME VERY WARM
TEMPERATURES TODAY.
SOMEWHAT PROBLEMATIC TODAY IS THE CURRENT FOG STRATUS AND DRIZZLE
SITUATION. THE SOUPY AIRMASS WILL HANG OVER THE FORECAST AREA THIS
MORNING AND AS THE WARMER AIR MOVES IN IT WILL CREATE AN INVERSION
OVER THE CWA THAT WILL BE VERY TOUGH TO BREAK BASED ON FORECAST
SOUNDINGS. IT DOES NOT LOOK LIKE THE INVERSION WILL BREAK DUE TO
MIXING THUS I AM KEEPING THE MENTION OF FOG AROUND A LITTLE LONGER
THAN THE PREVIOUS FORECAST HAD IT. HOWEVER SOUNDINGS DO INDICATE WE
MAY HAVE MORE OF A CEILING ISSUE. AS THE WINDS INCREASE LATE
MORNING THE FOG WILL THIN AND VISIBILITIES SHOULD IMPROVE
SOME...CERTAINLY ABOVE DENSE FOG CRITERIA AND WHILE CEILINGS WILL
LIFT I DO NOT SEE MUCH CHANCE OF THE FORECAST AREA BREAKING OUT
UNTIL LATE AFTERNOON AT THE EARLIEST WHEN THE SURFACE LOW SHIFTS
NORTHEAST AND BEGINS TO DRAG A COLD FRONT INTO THE AREA.
AS FOR TEMPS...COULD SEE SOME RECORD HIGHS TODAY ACROSS THE SOUTH.
THIS IS ESPECIALLY TRUE IN AREAS WITH NO SNOW COVER.
.LONG TERM /TONIGHT THROUGH THURSDAY/...
MAIN CHALLENGES THIS PERIOD WILL BE TEMPERATURES FOR THE WEEKEND AND
EARLY NEXT WEEK. SOME CONSENSUS ON THE TIMING OF THE COLD AIR BEHIND
THE BOUNDARY TONIGHT AND TOMORROW AS THE COLD AIR LOOKS TO LAG THE
BOUNDARY OVER CENTRAL AND SOUTHEAST IOWA BY ABOUT 6 TO 12 HOURS.
OTHERWISE IT SHOULD SETTLE INTO NORTHWEST AREAS THE QUICKEST. HAVE
TRIMMED THE TEMPS OVER THE NORTHWEST FOR BOTH AM LOWS SAT AND HIGHS
DURING THE AFTERNOON HOURS. THERE MIGHT BE SOME LEFT OVER PATCHY FOG
AND LIGHT DRIZZLE FAR NORTH THIS EVENING BEFORE THE FRONT SWEEPS
THROUGH. FOR THE REMAINDER OF SATURDAY MUCH OF THE FORECAST AREA
WILL BE BETWEEN THE DEPARTING NORTHERN STREAM LOW AND A SOUTHERN
STREAM LOW TRACKING THROUGH THE MID MISSISSIPPI RIVER VALLEY.
PREVIOUS RUNS OF ALL MED RANGE MODELS MAINTAINED A SOUTHERLY TRACK
AWAY FROM OUR AREA...BUT TONIGHTS 00Z EURO HAS NOW BACKED THE DEF
ZONE MUCH FARTHER NORTHWEST INTO SOUTHEAST IOWA AND BROUGHT NORTH
ABOUT .25 INCHES OF QPF OVER THE FAR SOUTHEAST SAT EVENING AND
OVERNIGHT INTO EARLY SUNDAY MORNING. THIS WOULD RESULT IN NEARLY A 2
TO 4 INCH BAND SOUTHEAST OF A LINE NEAR LAMONI TO ABOUT OTTUMWA WITH
JUST A DUSTING AS FAR NORTHWEST AS DES MOINES. THIS DEPARTURE NEEDS
SOME MONITORING AS IT MIGHT END UP BEING ACCUMULATING SNOWFALL THERE
AND TO THE EAST OF OUR FORECAST AREA IN EASTERN IOWA. FOR NOW WILL
NOT ADJUST TOO MUCH GIVEN THIS IS THE ONLY MODEL THAT FAR NORTHWEST
...BUT THE GEM IS ALSO TRENDING NORTHWEST A BIT. AFTER THE PASSAGE
OF THIS SYSTEM THE COLD AIR SETTLES ACROSS THE AREA WITH HIGH
PRESSURE ANCHORED OVER THE STATE FOR A FEW DAYS. BY LATE MONDAY THE
PATTERN SHIFTS TO A MORE ZONAL FLOW WITH ADIABATIC WARMING
COMMENCING AGAIN ACROSS THE PLAINS. THIS WILL END THE PROGRESSION OF
COLD AIR FOR NOW...WITH A WARM UP ON THE WAY BY MID WEEK. WITH LESS
SNOW COVER AND H850 TEMPS REACHING 2 TO 4C BY WED AFTERNOON...SHOULD
EASILY SEE MID TO UPPER 30S OVER THE AREA WITH LOWER 40S POSSIBLE IN
THE SOUTH. SINCE TRENDS HAVE NOT SHOWN GREAT CONSENSUS WILL USE THE
BLEND APPROACH. MILD WEATHER SLATED TO STICK AROUND FOR ABOUT 3 DAYS
BEFORE AN ARCTIC AIRMASS MAKES AN ATTEMPT TO CRASH SOUTHEAST BY
FRIDAY. PLENTY OF WRINKLES IN THE PATTERN CHANGE...IF ANY...SO WILL
HAVE TO MONITOR.
&&
.AVIATION...11/06Z
LIFR VIS AND CIGS WILL CONTINUE THROUGH THE NEXT FORECAST
PACKAGE...WITH CONDITIONS SLOWLY IMPROVING B/T 13-15Z FRIDAY
MORNING. THE LATEST HRRR MODEL RUN KEEPS LIFR/IFR CONDITIONS THROUGH
16Z ACROSS MUCH OF CENTRAL IOWA. FOR NOW...HAVE A SLOW TRANSITION TO
MVFR BY 18Z AS WAA INCREASES WITH THE TIGHT PRESSURE GRADIENT AHEAD
OF COLD FRONT. POTENTIAL TO HAVE MVFR STRATUS DECK PERSIST UNTIL THE
COLD FRONT SWEEPS ACROSS THE STATE PAST 06Z SATURDAY AND WAS
CONFIDENT ENOUGH TO KEEP MVFR CIGS AT ALO/FOD/MCW THROUGH FRIDAY
NIGHT.
&&
.DMX WATCHES/WARNINGS/ADVISORIES...
DENSE FOG ADVISORY THROUGH 9 AM CST FRIDAY FOR ADAIR-ADAMS-
APPANOOSE-AUDUBON-CASS-CLARKE-DALLAS-DAVIS-DECATUR-GUTHRIE-
JASPER-LUCAS-MADISON-MAHASKA-MARION-MONROE-POLK-POWESHIEK
-RINGGOLD-TAYLOR-UNION-WAPELLO-WARREN-WAYNE.
DENSE FOG ADVISORY THROUGH NOON CST FRIDAY FOR BLACK HAWK-BOONE
-BREMER-BUTLER-CALHOUN-CARROLL-CERRO GORDO-CRAWFORD-EMMET-
FRANKLIN-GREENE-GRUNDY-HAMILTON-HANCOCK-HARDIN-HUMBOLDT-
KOSSUTH-MARSHALL-PALO ALTO-POCAHONTAS-SAC-STORY-TAMA-WEBSTER
-WINNEBAGO-WORTH-WRIGHT.
&&
$$
SHORT TERM...FAB
LONG TERM...REV
AVIATION...PODRAZIK
AREA FORECAST DISCUSSION
NWS QUAD CITIES IA IL
1149 PM CST THU JAN 10 2013
.AVIATION...
LIFR AND IFR CONDITIONS TO PREVAIL ALL TERMINALS THROUGH AT LEAST
11/14Z. WARM MOIST AIR WITH AREAS OF LIGHT TO MODERATE DRIZZLE
WITH FOG WILL MOVE NORTH AS A SHORT WAVE PASSES LATE TONIGHT.
EXTENDED PERIODS OF CIGS AOB 500 FT AND VISIBILITY AOB 1 MILE WITH
DRIZZLE AND FOG CAN BE EXPECTED INTO LATE MORNING FRIDAY. ALL
TERMINALS MAY EXPERIENCE PERIODS BELOW AIRPORT MINIMUMS...LASTING
INTO THE MID MORNING HOURS. SOUTHEAST WINDS OF 5 TO 15 KTS WILL
SHIFT TO THE SOUTH AND SOUTHWEST FRIDAY. THE BRL AND MLI TERMINALS
WILL IMPROVE TO PROBABLY VFR CONDITIONS BY EARLY FRIDAY AFTERNOON
AS THE DISTURBANCE MOVES NORTHEAST AND MVFR CONDITIONS PROBABLE
AT CID/DBQ TERMINALS WHICH WILL BECOME VFR BY 12/00Z.
NICHOLS
&&
.PREV DISCUSSION... /ISSUED 319 PM CST THU JAN 10 2013/
SYNOPSIS...
12Z UA ANALYSIS HAS THE CUT OFF LOW IN WEST TEXAS WITH A 850MB
WARM FRONT RUNNING FROM CENTRAL OKLAHOMA INTO SOUTHEAST KANSAS. A
VERY SHARP 850MB MOISTURE GRADIENT RAN FROM NORTHWEST MISSOURI
INTO THE OHIO VALLEY. RADAR TRENDS THROUGH THE MORNING AND
AFTERNOON SHOW PLENTY OF VIRGA FROM NORTHERN IOWA INTO NORTHERN
ILLINOIS WITH SFC RAIN FROM SOUTHERN IOWA INTO CENTRAL ILLINOIS.
18Z SFC ANALYSIS HAS THE LOW IN SOUTHWEST OKLAHOMA WITH A
DEVELOPING BOUNDARY FROM CENTRAL OKLAHOMA TO NEAR KMEM. DEW POINTS
WERE IN THE 20S ACROSS THE GREAT LAKES WITH 30S AND 40S FROM THE
CENTRAL PLAINS INTO THE OHIO VALLEY. DEW POINTS IN THE 50S WERE IN
THE LOWER MISSISSIPPI VALLEY.
SHORT TERM...LATE THIS AFTERNOON AND TONIGHT
THE MOISTURE SURGE COMING UP FROM THE SOUTH IS STARTING TO WIN
OVER THE DRY AIR. SPOTTY RAIN OR DRIZZLE IS NOW OVER ROUGHLY THE
SOUTHERN HALF OF THE CWFA WITH SPRINKLES OR VERY SPOTTY RAIN
DEVELOPING OVER THE NORTHERN HALF.
RAP TRENDS INDICATE THAT A VERY RAPID TOP DOWN SATURATION WILL
OCCUR LATE THIS AFTERNOON. SO BY THE EVENING COMMUTE THERE SHOULD
BE FAIRLY WIDESPREAD VERY LIGHT RAIN OR DRIZZLE OCCURRING ACROSS
THE AREA.
TEMPERATURES WILL SLOWLY CLIMB LATE THIS AFTERNOON AS MOISTURE
CONTINUES TO SURGE INTO THE AREA. HIGH TEMPERATURES FOR THE
VERIFYING PERIOD WILL LIKELY OCCUR IN THE 6-8 PM TIME FRAME.
LIKEWISE...OVERNIGHT LOWS WILL LIKELY OCCUR IN THE 7-8 PM TIME
FRAME FOLLOWED BY STEADY OR SLOWLY RISING TEMPERATURES.
TONIGHT...STRONG FORCING MOVES ACROSS THE AREA DURING THE EVENING
WITH A FULLY SATURATED ATMOSPHERE. THE HEAVY RAIN TOOL SUGGESTS
THE EVENING HOURS WILL LIKELY ACCOUNT FOR MUCH OF THE RAINFALL
FROM THIS EVENT. AFTER MIDNIGHT...WIDESPREAD DRIZZLE WILL BE SEEN
BUT ANOTHER ROUND OF FORCING WILL LIKELY ALLOW SOME ADDITIONAL
RAIN TO OCCUR.
ANOTHER CONCERN TONIGHT IS FOG. THERE IS STILL A RESPECTABLE SNOW
FIELD OVER ROUGHLY THE NORTHERN THIRD OF THE CWFA. ADVECTING
MOISTURE INTO THE AREA ALONG WITH RAIN SHOULD ALLOW PATCHY OR SOME
AREAS OF FOG TO DEVELOP LATE THIS EVENING AS WINDS DIMINISH. AFTER
MIDNIGHT WINDS DROP OFF ACROSS THE NORTHWEST THIRD TO 40 PERCENT
OF THE CWFA WITH THE PASSAGE OF THE SFC LOW. AT THIS TIME THE RISK
FOR DENSE FOG WILL BE THE GREATEST.
THEREFORE...WILL ISSUE A DENSE FOG ADVISORY FOR THE MAIN SNOW
FIELD AND WHERE WINDS ARE PROGGED TO BE LIGHT. IT IS HIGHLY LIKELY
THAT THE DENSE FOG ADVISORY MAY HAVE TO BE EXPANDED DURING THE
EVENING OR OVERNIGHT HOURS. ..08..
LONG TERM...FRIDAY THROUGH NEXT WEDNESDAY...
HIGH TEMPERATURES FOR FRIDAY ARE A LARGE QUESTION MARK THIS
FORECAST. THE MAIN COMPLICATING FACTOR IS IN HOW QUICKLY THE LOW
CLOUDS CLEAR FROM SOUTH TO NORTH WITH THE ASSOCIATED CLEARING OF THE
FOG AND DRIZZLE. MODELS HAVE BEEN STRUGGLING WITH THIS ISSUE...WITH
MANY OF THEM KEEPING A TRAPPED LOWER LAYER OF LOW CLOUDS AND FOG
WITH A STRONG ELEVATED MIXED LAYER OVER THE TOP OF IT.
HOWEVER...THEY ALSO DEPICT STRONG SURFACE WINDS...WHICH DOES NOT
MATCH WELL WITH A TRAPPED LOW LEVEL INVERSION. A LOOK AT THE MODEL
INITIALIZATION SHOWS THAT NAM12 MODEL SNOW DEPTH INITIALIZATION IS
FAR TOO FAR SOUTH...WITH 1 INCH OR MORE OF SNOW DEPTH INTO NORTHERN
MISSOURI. GEM AND RUC ARE CLOSER TO REALITY. GFS MODEL SNOW DEPTH
INITIALIZATION MAY NOT BE ANY BETTER THAN THE NAM12...BUT CANNOT
CHECK ON THAT AT THIS TIME. THUS...HAVE DECIDED TO DEFINITELY ALLOW
THE CLOUDS TO CLEAR OUT OF THE SNOW FREE AREAS ACROSS THE SOUTHERN
HALF TO TWO THIRDS OF THE FORECAST AREA...ALLOWING HIGH TEMPS TO GET
INTO THE MID TO UPPER 50S IN THE AFTERNOON. HOWEVER THE NORTH IS A
WHOLE SEPARATE CAN OF WORMS...WITH THE LOW CLOUDS FOG AND DRIZZLE
HANGING ON INTO THE AFTERNOON AND KEEPING TEMPERATURES IN THE 40S TO
NEAR 50 FOR THE MOST PART. THIS MAKES A LARGE RANGE ACROSS THE
FORECAST AREA IN MAX TEMPS...AND STILL LEAVES US WITH A LARGE BUST
POTENTIAL FOR THIS FORECAST. WITH THIS EXTRAORDINARY WARMTH...THE
RECORD HIGH TEMPERATURE FOR BURLINGTON IS AT RISK...AND WE WILL BE
CLOSE AT OTHER LOCATIONS. FOR REFERENCE...HAVE INCLUDED RECORD HIGHS FOR
FRIDAY BELOW.
OF COURSE...THIS IS NOT THE ONLY CONCERN THIS FORECAST. FRIDAY
NIGHT WILL BE MILD WITH TEMPERATURES REMAINING UP. IN
FACT...LOCATIONS ACROSS THE NORTH THAT DO NOT GET INTO THE SUNSHINE
WILL SLOWLY RISE INTO THE EVENING HOURS AND WILL REACH THEIR HIGH
TEMPERATURES IN THE LATE EVENING TO AROUND MIDNIGHT. THE STRONG
COLD FRONT COMES THROUGH EARLY SATURDAY MORNING AND TEMPERATURES
BEGIN TO FALL...WITH ONLY MINIMAL DIURNAL RISE IN THE AFTERNOON.
SATURDAY NIGHT AND SUNDAY THERE IS A WEAK SHORTWAVE THAT MOVES ALONG
A BAROCLINIC ZONE DRAPED FROM TEXAS UP THE OHIO RIVER VALLEY..WHICH
SHOULD PRODUCE A NICE BAND OF SNOW FOR AREAS NORTHWEST OF THE LOW
TRACK. THE TRICK IS WHETHER THIS SYSTEM WILL SHIFT FAR ENOUGH
NORTHWEST TO BRING SOME ACCUMULATING SNOWS TO THE FORECAST AREA
SATURDAY NIGHT AND EARLY SUNDAY. FOR NOW IT APPEARS THAT THE
SOUTHEAST PORTIONS OF THE AREA WILL GET SOME LIGHT SNOW
ACCUMULATIONS...BUT THE NORTHWEST EDGE OF THIS SNOW BAND WILL BE
FAIRLY SHARP...AND THE QUAD CITIES IS PROBABLY ONLY LOOKING SOME
PRETTY MINOR ACCUMULATIONS...DUSTING TO A HALF INCH PERHAPS.
BEHIND THIS SYSTEM WE ARE LOOKING AT GETTING SOME VERY COLD
TEMPERATURES INTO THE AREA...WITH 850MB TEMPS DROPPING TO AROUND
-10C BY MONDAY MORNING. AS LONG AS WE CLEAR OFF...TEMPERATURES WILL
DROP INTO THE TEENS. TEMPERATURES SHOULD SLOWLY MODERATE INTO
WEDNESDAY. ANOTHER LONGWAVE TROUGH IS EXPECTED TO MOVE THROUGH THE
AREA WEDNESDAY...BUT IT IS TOO DRY TO BRING MORE THAN A FRESH SHOT
OF COLDER AIR FOR THURSDAY.
LE
CLIMATE...
CORRECTED THESE RECORD HIGHS.
RECORD HIGHS FOR JANUARY 11...
MOLINE.........56 IN 2012
CEDAR RAPIDS...53 IN 2012
DUBUQUE........52 IN 2012
BURLINGTON.....55 IN 2012
&&
.DVN WATCHES/WARNINGS/ADVISORIES...
IA...DENSE FOG ADVISORY UNTIL 10 AM CST FRIDAY FOR BENTON-BUCHANAN-
DELAWARE-DUBUQUE-IOWA-JACKSON-JOHNSON-JONES-LINN.
IL...DENSE FOG ADVISORY UNTIL 10 AM CST FRIDAY FOR CARROLL-JO DAVIESS-
STEPHENSON.
MO...NONE.
&&
$$
NICHOLS
AREA FORECAST DISCUSSION
NWS DES MOINES IA
1143 PM CST THU JAN 10 2013
...UPDATED AVIATION DISCUSSION...
.SHORT TERM /TONIGHT/...
LOW LEVEL MOISTURE FINALLY WORKING ITS WAY ACROSS THE CWA...WITH
LARGE AREA OF LIGHT RAIN LIFTING NORTHWARD THROUGH THE STATE.
ASSOCIATED UPPER LEVEL LOW CURRENTLY SPINNING OVER OKLAHOMA TO LIFT
NORTHEASTWARD INTO CENTRAL ILLINOIS BY 12Z FRIDAY. SOUTHERLY FLOW
AND STRONG WAA/MOISTURE ADVECTION TO CONTINUE ACROSS THE AREA THIS
EVENING...WITH MORE SOUTHWESTERLY FLOW BY LATE TONIGHT. NAM ALSO
SHOWING STEADY ISENTROPIC LIFT THROUGHOUT THE LOWEST FEW LAYERS
TONIGHT...THEREFORE EXPECT STEADIER LIGHT RAIN TO TRANSITION TO
DRIZZLE ACROSS MUCH OF THE AREA TONIGHT WITH SOUNDINGS ACROSS THE
CWA STILL SUGGESTING FAIRLY DEEP SATURATED LAYER. THEREFORE KEPT
POPS IN THE LIKELY TO CATEGORICAL RANGE OVERNIGHT AS EXPECT COULD
SEE A FEW HUNDREDTHS QPF WITH THE DRIZZLE. TEMPERATURES EXPECTED TO
REMAIN JUST ABOVE FREEZING ACROSS THE NORTH...THEREFORE HAVE STUCK
WITH DRIZZLE MENTION. SREF HINTED AT POSSIBILITY OF SFC TEMPS
DROPPING BELOW FREEZING FOR A FEW HOURS LATE TONIGHT NEAR MASON CITY
TO ESTHERVILLE. WILL HAVE TO MONITOR...BUT MOST OTHER MODELS KEEPING
SFC TEMPS ABOVE FREEZING WITH THE CLOUDS/PRECIP/FOG AND NEAR NEUTRAL
TO WAA...SO HAVE TRENDED TEMPERATURES TOWARD THE WARMER SOLUTIONS.
WITH THE ABUNDANCE OF MOISTURE IN THE NEAR SURFACE LAYERS...AND
ANTICIPATED SNOW MELT AS DEWPOINTS REMAIN ABOVE FREEZING OVERNIGHT
WITH THE LIGHT RAIN/DRIZZLE FOG DEVELOPMENT SEEMS QUITE CERTAIN.
ADDITIONALLY DENSE FOG ALSO POSSIBLE ACROSS ENTIRE CWA...ESPECIALLY
IN AREAS WITH DEEPER SNOWPACK. THEREFORE WILL ISSUE A DENSE FOG
ADVISORY FOR THE ENTIRE CWA FOR MAINLY LATE EVENING/LATE TONIGHT
INTO FRIDAY MORNING.
.LONG TERM /FRIDAY THROUGH THURSDAY/...
AS THE OVERNIGHT PRECIPITATION SYSTEM DEPARTS EAST OF THE MISSOURI
RIVER EARLY FRIDAY...A DEEPER LOW WILL DEVELOP EAST OF THE ROCKIES
AND SWING THROUGH NEBRASKA. NET EFFECT WILL BE INCREASING SOUTH FLOW
ACROSS IOWA FRIDAY...PROLONGING TRANSPORT OF LOW-LEVEL MOISTURE AND
WARMTH NORTH ACROSS SNOW PACK. AT MID AND UPPER LEVELS...A STRONG
DRY SLOT WILL SURGE NORTHEAST ACROSS IOWA. LOW CLOUDS/FOG/DRIZZLE
SHOULD BREAK UP FRIDAY MORNING FROM I-80 SOUTH...BUT IT IS LIKELY TO
LINGER ALL DAY THE FARTHER NORTH YOU GO. IT WILL BE VERY WARM IN
SOUTHERN IOWA...WHERE SNOW FREE AREAS SOUTH OF I-80 COULD APPROACH
OR EXCEED RECORDS WHICH ARE GENERALLY IN THE MIDDLE 50S. THE DENSE
FOG ADVISORY WILL CONTINUE THROUGH NOON...AND WE`LL SEE WHAT IS
NEEDED THEREAFTER. WITH THE COLD FRONT NOT SCHEDULED TO CROSS I-35
UNTIL ABOUT MIDNIGHT FRIDAY NIGHT...THERE IS A CHANCE THE FOG AND
SOME DRIZZLE COULD LINGER IN NORTHERN IOWA UNTIL THEN. THE GOOD NEWS
IS THAT TEMPERATURES WILL REMAIN ABOVE FREEZING UNTIL THE COLD AIR
HITS...WHICH WILL BE ACCOMPANIED BY DRYING AS WELL...SO NO FREEZING
PRECIPITATION EXPECTED.
TEMPERATURES WILL FALL RAPIDLY FRIDAY NIGHT AND NOT RECOVER MUCH ON
SATURDAY. MAY GET SOME LOW CLOUDS AND FLURRIES MIGHT BE POSSIBLE IN
THE FAR NORTHWEST...BUT DEEPER LIFT ZONE WILL TRACK WELL NORTH OF
IOWA. ALTHOUGH COLD AIR WILL SURGE IN AT LOW LEVELS...FLOW ALOFT
WILL REMAIN FROM THE SOUTHWEST. ON SATURDAY NIGHT...IOWA WILL BE ON
THE NORTH FRINGE OF A PRECIPITATION SYSTEM...BUT LIMITING
STREAMLINES LOOK LIKELY TO KEEP LIGHT SNOW CHANCE CONFINED TO THE
FAR SOUTHEAST OF THE FORECAST AREA.
FOR THE REST OF THE FORECAST...NO PRECIPITATION IS EXPECTED.
FLUCTUATING TEMPERATURES ARE LIKELY...AND CERTAINLY COOLER THAN THIS
WEEK...BUT NOT LOOKING EXTREME. GFS/ECMWF 12Z MODEL SOLUTIONS BEGIN
TO DIVERGE STARTING TUESDAY NIGHT. GFS IS FASTER AND GENERALLY
STRONGER WITH A COLD FRONT AND COLD SURGE THEN. FORECAST AT
THIS TIME SHOWS SOMETHING OF A MIDDLE OF THE ROAD FORECAST...BUT IT
APPEARS FORECAST RELIABILITY IS IFFY AS FAR AS AMOUNT OF COLD FOR
MID AND LATE NEXT WEEK. COLD POOL LOOKS LIKELY TO REMAIN OVER HUDSON
BAY WITH COLDER AIR OVER THE GREAT LAKES...WITH SOME INROADS INTO
IOWA.
&&
.AVIATION...11/06Z
LIFR VIS AND CIGS WILL CONTINUE THROUGH THE NEXT FORECAST
PACKAGE...WITH CONDITIONS SLOWLY IMPROVING B/T 13-15Z FRIDAY
MORNING. THE LATEST HRRR MODEL RUN KEEPS LIFR/IFR CONDITIONS THROUGH
16Z ACROSS MUCH OF CENTRAL IOWA. FOR NOW...HAVE A SLOW TRANSITION TO
MVFR BY 18Z AS WAA INCREASES WITH THE TIGHT PRESSURE GRADIENT AHEAD
OF COLD FRONT. POTENTIAL TO HAVE MVFR STRATUS DECK PERSIST UNTIL THE
COLD FRONT SWEEPS ACROSS THE STATE PAST 06Z SATURDAY AND WAS
CONFIDENT ENOUGH TO KEEP MVFR CIGS AT ALO/FOD/MCW THROUGH FRIDAY
NIGHT.
&&
.DMX WATCHES/WARNINGS/ADVISORIES...
DENSE FOG ADVISORY FROM 9 PM THIS EVENING TO 9 AM CST FRIDAY FOR
ADAIR-ADAMS-APPANOOSE-AUDUBON-CASS-CLARKE-DALLAS-DAVIS-DECATUR-
GUTHRIE-JASPER-LUCAS-MADISON-MAHASKA-MARION-MONROE-POLK-POWESHIEK-
RINGGOLD-TAYLOR-UNION-WAPELLO-WARREN-WAYNE.
DENSE FOG ADVISORY FROM MIDNIGHT TONIGHT TO NOON CST FRIDAY FOR
BLACK HAWK-BOONE-BREMER-BUTLER-CALHOUN-CARROLL-CERRO GORDO-
CRAWFORD-EMMET-FRANKLIN-GREENE-GRUNDY-HAMILTON-HANCOCK-HARDIN-
HUMBOLDT-KOSSUTH-MARSHALL-PALO ALTO-POCAHONTAS-SAC-STORY-TAMA-
WEBSTER-WINNEBAGO-WORTH-WRIGHT.
&&
$$
SHORT TERM...MJB
LONG TERM...JUNGBLUTH
AVIATION...KLP
AREA FORECAST DISCUSSION...UPDATED
NWS MARQUETTE MI
1114 PM EST THU JAN 10 2013
.UPDATE...
ISSUED AT 1112 PM EST THU JAN 10 2013
ON SECOND THOUGHT...WILL GO AHEAD AND ISSUE FREEZING RAIN ADVISORY
FOR THE AREAS AWAY FROM THE WARMING OF LAKE MICHIGAN. APPEARS THAT
EVEN THOUGH TEMPERATURES ARE SEVERAL DEGREES ABOVE FREEZING...THE
BELOW FREEZING SURFACE TEMPS ARE ENOUGH TO CAUSE ICING ON SOME
ROADWAYS IN THOSE AREAS. WITH MIDOT SITES SHOWING ROAD SURFACE TEMPS
AROUND 28 IN IRON COUNTY AND SEVERAL REPORTS OF LIGHT ICING IN IRON
MOUNTAIN AND IRON RIVER...FEEL THAT THE CURRENT ADVISORY IS IN GOOD
SHAPE. TEMPS ARE FINALLY STARTING TO FALL IN IRONWOOD...DOWN TO
36...BUT WITH MIDOT ROAD SFC TEMPS IN TWIN LAKES AROUND 32...THOUGHT
IT WOULD BE A LITTLE MORE PATCHY THERE AND FOCUSED OVER FAR EASTERN
GOGEBIC COUNTY. LATEST OBSERVER REPORT INDICATED THAT MAIN ROADS WERE
WET BUT SECONDARY SNOW COVERED ROAD WAS SLICK. THUS...WILL KEEP THE
SPS GOING FOR FOR LOCATIONS OUTSIDE THE ADVISORY.
INITIAL WAVE OF PRECIPITATION SHOULD BE DIMINISHING FROM SOUTH TO
NORTH OVER THE WESTERN THIRD OF THE CWA OVER THE NEXT COUPLE OF
HOURS AND THEN WILL LIKELY SEE FOG/DRIZZLE FOR THE REST OF THE
NIGHT. OVER THE CENTRAL AND EASTERN CWA...SECOND WAVE OF
PRECIPITATION CURRENTLY EXITING NORTHERN ILLINOIS WILL BRING ANOTHER
PERIOD OF RAIN TOWARDS 08-13Z. SURFACE TEMPS WILL BE SLIGHTLY WARMER
AT THAT TIME...BUT STILL COULD SEE SOME ISSUES ON SECONDARY OR SNOW
COVERED ROADS.
PREVIOUS UPDATE
ISSUED AT 835 PM EST THU JAN 10 2013
FORECAST UPDATE MAINLY FOR POTENTIAL FREEZING RAIN THIS EVENING AND
TONIGHT. ONLY MADE MINOR TWEAKS TO THE GOING POPS TO FINE TUNE THE
SHARP START TO THE RAIN. WITH THE STRONG WARM AIR ADVECTION CREATING
A LARGE WARM LAYER ALOFT BASED ON RUC SOUNDINGS...THE PRECIPITATION
WILL FALL AS RAIN. THE QUESTION BECOMES WHAT WHILL HAPPEN ONCE IT
REACHES THE SURFACE. LOOKING AT MIDOT ROAD SENSORS ACROSS THE
CENTRAL CWA...SURFACE TEMPERATURES ARE AROUND 29-30 DEGREES.
THUS...THINKING THAT EVEN IF NEAR SURFACE TEMPERATURES ARE AT OR
JUST ABOVE FREEZING...THERE WILL STILL BE SOME FREEZING ON THE
LESSER TRAVELED ROADWAYS. THEREFORE...OPTED TO ISSUE A FREEZING RAIN
ADVISORY FOR IRON/DICKINSON COUNTIES AT THIS TIME DUE TO HAVING THE
HIGHEST CONFIDENCE FOR OCCURENCE. WAS ON THE EDGE FOR
BARAGA/MARQUETTE COUNTIES FOR THE HIGHER TERRAIN LOCATIONS THAT ARE
ALREADY HOVERING NEAR FREEZING. THE OTHER AREAS SHOULD ONLY SEE VERY
ISOLATED AREAS AND ISSUED AN SPS FOR THEM. HIGH RESOLUTION MODELS
SHOWING DOWNSLOPE WARMING HELPING OVER THE FAR WEST AND OFF LAKE
MICHIGAN OVER THE EAST. IN ADDITION...WITH TEMPS OUT WEST STILL
AROUND 40...DIDN/T FEEL COMFORTABLE ISSUING ONE FOR
GOGEBIC/ONTONAGON. EVEN THOUGH THOSE AREAS ARE WARMER...COLD GROUND
TEMPS COULD STILL PRODUCE SOME SLICK SPOTS.
&&
.SHORT TERM...(THIS EVENING THROUGH FRIDAY)
ISSUED AT 417 PM EST THU JAN 10 2013
TONIGHT...LATEST WATER VAPOR LOOP SHOWS WELL-DEFINED SHORTWAVE OVER
SRN OKLAHOMA. MODELS IN GOOD AGREEMENT ON TRACK OF THIS SHORTWAVE
WHICH IS FCST TO MOVE UP THE MS VALLEY LATER TONIGHT AND THEN INTO
THE LOWER GREAT LAKES ON FRIDAY. MODEL SNDGS CONSISTENT IN SHOWING
DEEP MOISTURE ARRIVING NOT UNTIL LATE THIS EVENING/OVERNIGHT...WITH
MOST PRECIPITATION HOLDING OFF ACROSS THE SOUTHERN CWA UNTIL AFT
03Z. COULD SEE SOME COOLING TO BELOW FREEZING TEMPS ACROSS INTERIOR
LOCATIONS OF THE CWA BEFORE CLOUDS THICKEN WITH THE ARRIVAL OF DEEP
MOISTURE...ESPECIALLY OVER THE WEST HALF WHERE DEWPOINTS ARE STILL
IN THE LOW TEENS AT MANY LOCATIONS. INITIALLY LOWER SFC WET-BULB
TEMPS DUE TO THIS DRIER AIRMASS COULD RESULT IN SOME LIGHT FREEZING
RAIN AT ONSET OF PCPN...BUT AS IN LINE WITH PREV FCST
THINKING...STILL EXPECT TEMPS TO WARM BACK TO IF NOT ABOVE FREEZING
SHORTLY AFTER ONSET OF PRECIPITATION. WITH SSE WINDS PUMPING IN
WARMER AND MORE MOIST AIR THROUGH THE OVERNIGHT HRS...BELIEVE ANY
FREEZING RAIN WILL BE SHORT-LIVED AND PCPN WILL EVENTUALLY TURN OVER
TO ALL RAIN LATER TONIGHT. SO FREEZING RAIN ADVISORY SHOULD NOT BE
NEEDED...BUT PERHAPS AN SPECIAL WEATHER STATEMENT MAY BE NEEDED FOR
EXPECTED SHORT DURATION EVENT.
MODELS STILL SEEM TO INDICATE THE BULK OF THE PRECIP WILL REMAIN
SOUTHEAST OF THE CWA...BUT BRIEF MODERATE RAINFALL COULD AFFECT THE
EAST HALF OF THE CWA AS A RESULT OF STRONG ISENTROPIC LIFT ALONG THE
295-305K SURFACES ON THE NOSE OF A 45-50 KT LLJ AS PRECIPITABLE
WATER VALUES SURPASS ONE INCH (450 PERCENT NORMAL) ACROSS THE EAST
HALF. HAVE SPREAD CATEGORICAL POPS ACROSS THE CWA FROM LATE EVENING
INTO EARLY OVERNIGHT HRS.
FRIDAY...SHORTWAVE PASSES WELL SOUTHEAST ALLOWING WEAK RDGG AND
Q-VECT DIV TO SPREAD IN FROM THE WEST....RESULTING IN DIMINISHING
RAIN CHCS FROM WEST TO EAST DURING THE DAY. DESPITE LINGERING LOW
CLOUDS...EXPECT MAX TEMPS FRI TO BE WELL ABOVE NORMAL GIVEN
UNSEASONABLE WARMTH TONIGHT AND CONTINUED LOW-LEVEL SSW FLOW AHEAD
OF WRN TROF THRU FRI.
.LONG TERM...(FRIDAY NIGHT THROUGH THURSDAY)
ISSUED AT 417 PM EST THU JAN 10 2013
FRI NIGHT...AS SHRTWV LIFTS NEWD OUT OF MEAN TROF OVER THE W HALF OF
NAMERICA...A SFC LO IS PROGGED TO MOVE FM THE PLAINS TO NE MN BY 12Z
SAT. THE FASTER 12Z NAM/CNDN MODELS SHOW ATTENDANT SFC COLD FNT
SWINGING THRU THE FAR W ARND IWD BY 12Z...BUT BULK OF OTHER GUIDANCE
INDICATES A SLOWER FROPA. MODELS INDICATE DRY SLOT UNDER THE JET
SURGE REGION ON THE ERN FLANK OF THE SHRTWV WL DOMINATE THRU THE
NGT...SO EXPECT GENERALLY DRY WX TO PREVAIL WITH ACCOMPANYING
DPVA/LARGER SCALE QVECTOR CNVGC/DEEPER MSTR ASSOCIATED WITH SHRTWV
IMPACTING MAINLY AREAS TO THE W OF UPR MI ON THE CYC SIDE OF THE
TRACK OF THIS DISTURBANCE. RETAINED SOME LO CHC POPS OVER THE LAND
CWA FOR THE POTENTIAL OF MAINLY SOME -DZ. WITH A STEADY S WIND AND
LINGERING LO CLD...EXPECT MIN TEMPS TO RUN WELL ABV NORMAL AGAIN...
EVEN IF SOME COLDER AIR ARRIVES OVER THE FAR W LATE BEHIND A FROPA.
THERE WL BE AREAS OF FOG AWAY FM THE DOWNSLOPE AREAS NEAR LK SUP
WITH MOIST LLVLS/MELTING SN.
SAT...AS SHRTWV/SFC LOW IN NE MN AT 12Z MOVES ENE THRU NRN
ONTARIO...SHARP COLD FRONT WILL CROSS UPPER MI. HOWEVER...SINCE
STRONGEST DEEP LAYER QVECTOR CONVERGENCE ACCOMPANYING DISTURBANCE WL
PASS TO THE N...AXIS OF MIDLVL DRY AIR IS FCST TO LINGER. WITH
ABSENCE OF DYNAMIC FORCING...FROPA SHOULD BE MAINLY DRY. ONLY
EXCEPTION MAY BE OVER THE W...CLOSER TO THE PASSING DYNAMICS/DEEPER
MOISTURE AND WHERE THE LLVL FLOW WILL TAKE ON MORE OF A CYC UPSLOPE
COMPONENT...ESPECIALLY IN THE AFTN. THE ARRIVAL OF H85 TEMPS ARND
-15C TOWARD 00Z SUN WILL ALSO ADD AN INCREASING LES COMPONENT TO THE
MIX. BUT MODELS HAVE TRENDED TOWARD A MORE WSW LLVL FLOW AND HOLDING
THE MORE IMPRESSIVE MOISTENING FARTHER TO THE W... SO LOWERED POPS
EVEN OVER THE FAR W EXCEPT FOR THE KEWEENAW. WITH ARRIVAL OF COLDER
AIR/DECREASING STABILITY...APRCH OF SHARP PRES RISE CENTER WITH
ISALLOBARIC WIND ALIGNED ALONG THE GRADIENT FLOW... AND SHARPENING
PRES GRADIENT ON THE SRN FLANK OF THE LO SHIFTING THRU NRN ONTARIO
THAT PUSHES H925 WINDS UP TO 25-35 KTS...IT WILL BE WINDY. IN
COMBINATION WITH FALLING SFC TEMPS W TO E THRU THE DAY... THE AIR WL
BEGIN TO FEEL MUCH COLDER...ESPECIALLY OVER THE W.
SAT NGT THRU SUN NGT...AS COLDER AIR POURS INTO THE UPR GREAT LKS...
H85 TEMPS ARE PROGGED TO FALL TO -16 TO -18C. PREVIOUS FCST LIKELY
POPS FOR LES LOOK ON TRACK IN AREAS FAVORED BY EXPECTED WNW FLOW
ALONG LK INDUCED TROF FCST TO EXTEND FM THE KEWEENAW INTO THE AREAS
E OF MQT. CONSIDERING THE MORE THAN SUFFICIENT THERMAL
INSTABILITY...DENDRITIC SNOW GROWTH TEMPS FALLING FIRMLY INTO THE
CONVECTIVE LAYER...AND RATHER DEEP MSTR SHOWN BY SOME OF THE
GUIDANCE ALONG THE TROF...MDT SNOW ACCUMS IN THE ADVY CATEGORY WL BE
PSBL IN THE FAVORED SN BELTS.
MON-THU...ALTHOUGH THE PERSISTENT UPR RDG OVER THE SE CONUS THAT
MAINTAINS MORE OF A CONFLUENT FLOW ALF BTWN THE SPLIT NRN/SRN
BRANCHES INTO THE GRT LKS WL LIMIT THE SPREAD OF ARCTIC AIR BOTTLED
UP IN CANADA EARLY IN THE EXTENDED PERIOD...A NUMBER OF THE EXTENDED
MODELS AND THEIR ENSEMBLE MEANS ARE HINTING A NRN BRANCH TROF
CENTERED OVER HUDSON BAY WL DEEPEN BY MID WEEK AS A SERIES OF
SHRTWVS PLUNGE INTO THE NCNTRL CONUS. CONFIDENCE IN THIS SCENARIO IS
INCREASED BY UPR RDG FCST TO BLD OVER GREENLAND WITH BLOCKING AT HI
LATITUDES. IF THIS NEGATIVE NAO PATTERN DOES INDEED DVLP...MUCH
COLDER ARCTIC AIR MAY SURGE INTO THE AREA ON WED/THU. IN FACT...THE
00Z ECWMF IS ADVERTISING H85 TEMPS IN THE -20C TO -25C RANGE BY THU.
AS FOR DAY TO DAY WX...MON/TUE MAY BE RELATIVELY QUIET WITH A WSW
LLVL FLOW ARND SFC HI PRES BRIEFLY ADVECTING SOMEWHAT MILDER AIR AND
LIMITING LES... H85 TEMPS ARND -10C...INTO THE UPR LKS. THE
COMBINATION OF PASSING SHRTWVS/ARRIVAL OF COLDER AIR WL THEN
INCREASE THE POTENTIAL FOR SGNFT LES ON WED/THU. TENDED HIER THAN
MODEL CONSENSUS POPS FOR THIS TIME PERIOD IN THE FAVORED SN BELTS.
OTRW...NO LARGE SCALE PCPN EVENTS APPEAR TO BE ON THE HORIZON.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z FRIDAY EVENING)
ISSUED AT 635 PM EST THU JAN 10 2013
LINGERING DRY AIR WILL PRODUCE VFR CONDITIONS AT THE TAF SITES FOR
THE FIRST COUPLE OF HOURS. BROAD AREA OF RAIN CURRENTLY MOVING
NORTH THROUGH SOUTHERN WISCONSIN WILL BE MOVE ACROSS UPPER MICHIGAN
LATE THIS EVENING AND OVERNIGHT. THIS WILL DROP CEILINGS TO
IFR DURING THE OVERNIGHT HOURS...WITH SOME SITES AT ALTERNATE
LANDING MINIMUMS. BEHIND THE WAVE OF PRECIPITATION...WARM MOIST AIR
WILL LEAD TO LOW CLOUDS THROUGH THE REST OF THE PERIOD AND ALSO
SOME FOG. EXPECT THE FOG TO HAVE THE LOWEST VISIBILITIES AT KSAW
WITH THE FAVORABLE SSE FLOW INITIALLY AND THEN BACKING TO THE SW.
THERE MAY BE SOME SLIGHT LIFT TO THE CEILINGS ABOVE ALTERNATE
LANDING MINS TOMORROW AFTERNOON...BUT THEY WILL LIKELY GO BACK DOWN
AS THE SUN SETS AND FOG REDEVELOPS.
FINALLY...DID ADD A TEMPO FOR KSAW DURING THE FIRST COUPLE OF HOURS
DUE TO FAVORABLE UPSLOPE FLOW FROM THE CLOUDS FROM THE CLOUDS COMING
OFF LAKE MICHIGAN.
&&
.MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 417 PM EST THU JAN 10 2013
A TIGHT PRESSURE GRADIENT BTWN APPROACHING LOW PRESSURE TROUGH FROM
THE NRN PLAINS AND A HIGH PRES RDG OVER THE ERN LAKES WILL RESULT IN
SOUTH TO SOUTHEAST WINDS TO 25 KNOTS ACROSS THE ERN HALF OF LAKE
SUPERIOR TONIGHT INTO FRI MORNING. WINDS SHOULD STAY AT OR BELOW 20
KTS OVER THE WEST HALF. A STRONG TEMPERATURE INVERSION ABOVE THE
SURFACE SHOULD KEEP STRONG WINDS ALOFT FROM MIXING TO THE
SURFACE...BUT A FEW GUSTS OVER 30 KNOTS OVER THE EAST HALF ARE NOT
OUT OF THE QUESTION. WINDS WILL DIMINISH BLO 20 KT FRI AFTERNOON AS
PRES GRADIENT WEAKENS.
WITH WEAK PRES GRADIENT OVER THE LAKE FRI EVNG...EXPECT SSW WINDS
UNDER 20 KTS WINDS. BUT THESE WINDS WILL INCREASE LATER FRI NIGHT
W-E AS A DEEP LO PRES SYSTEM MOVES NE FROM THE PLAINS INTO NE MN AND
SHARPENS THE GRADIENT. LOOK FOR THESE WINDS TO THEN INCREASE RAPIDLY
ON SAT AS THE SHARP COLD FRONT SLICES ACROSS THE UPPER GREAT LAKES
AND THE ARRIVAL OF MUCH COLDER AIR RESULTS IN DECREASING STABILITY/
GREATER MIXING OF THE STRONGER WINDS TO THE LAKE SURFACE. OPTED TO
HOIST GALE WATCH FOR THE W HALF GIVEN TERRAIN ENHANCED WSW FLOW AND
APPROACH OF PRES RISE CENTER THAT WILL SHARPEN THE LARGER SCALE
WINDS. THE COMBINATION OF THE STRONG WINDS/COLDER AIR/HIER WAVES
WILL RESULT IN FREEZING SPRAY AS WELL INTO SAT NIGHT WHEN THE WINDS
WILL BE DIMINISHING WITH DEPARTURE OF LO PRES TO THE NE/WEAKENING
GRADIENT. WINDS ON SUN INTO MON ARE FORECAST IN THE 15 TO 25 KT
RANGE FOR THE MOST PART...BUT THE APPROACH OF ANOTHER DISTURBANCE
LATER ON TUE/TUE NIGHT MIGHT RESULT IN W-SW WINDS INCREASING UP TO
30 KTS AND MORE FREEZING SPRAY.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
FREEZING RAIN ADVISORY UNTIL 7 AM EST /6 AM CST/ FRIDAY FOR
MIZ001>007-009>011-084-085.
LAKE SUPERIOR...
GALE WATCH FROM SATURDAY MORNING THROUGH SATURDAY EVENING FOR
LSZ162-263-264.
LAKE MICHIGAN...
NONE.
&&
$$
UPDATE...SRF
SHORT TERM...VOSS
LONG TERM...KC
AVIATION...SRF
MARINE...VOSS/KC
AREA FORECAST DISCUSSION
NWS RALEIGH NC
315 AM EST FRI JAN 11 2013
.SYNOPSIS...
HIGH PRESSURE WILL EXTEND ACROSS THE REGION OVERNIGHT. A WARM FRONT
WILL LIFT NORTHWARD ACROSS CENTRAL NC THIS AFTERNOON AND TONIGHT.
HIGH PRESSURE ANCHORED OFF THE GEORGIA-NORTHEAST FLORIDA COAST WILL
BRING SPRING LIKE TEMPERATURES TO THE CAROLINAS THIS WEEKEND.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 300 AM FRIDAY...
WITHIN AN AMPLIFIED LONGWAVE PATTERN OVER THE CONUS...THE REMNANTS
OF THE UPPER THAT WAS OVER TX YESTERDAY IS NOW LIFTING NORTHEAST
ACROSS THE MID MS RIVER VALLEY REGION...WHILE A 1034MB SURFACE HIGH
OVER NEW ENGLAND EXTENDS SOUTH INTO THE CAROLINAS. STRENGTHENING
LOW LEVEL FLOW ON THE EASTERN FLANK OF THE LLJ OVER TN/KY IS LEADING
TO INCREASING WARM ADVECTION AND ISENTROPIC ACCENT ATOP THE SURFACE
RIDGE AXIS OVER CENTRAL NC THIS MORNING. THE SHALLOW LIFT WILL BE
MAXIMIZED THROUGH 15Z OVER THE WESTERN CWA...SHIFTING AND WEAKENING
TO THE NORTH AND EAST THIS AFTERNOON. MOST OF THE ECHOES CURRENTLY
SHOWING UP ARE NOW STARTING TO REACH THE GROUND...WITH MORE AND MORE
SITES REPORTING LIGHT RAIN OR DRIZZLE. BASED ON RAP SOUNDINGS...
MOISTURE IS MOSTLY FOCUSED BELOW THE FREEZING LEVEL AND EVEN AS THE
AXIS OF DEEPER MOIST AXIS ASSOCIATED WITH THE AFOREMENTIONED
SHORTWAVE SHIFTS EAST ACROSS THE MOUNTAINS THIS MORNING...MOISTURE
NEAR -10C WILL BE VERY LIMITED. THUS...LIKELY POPS FOCUSED OVER THE
WESTERN HALF OF THE CWA WILL MAINLY BE FOR EVERY LIGHT RAIN/DRIZZLE
WITH ONLY A TRACE OR A FEW HUNDREDTHS OF QPF.
THIS LACK OF SIGNIFICANT PRECIP MAKES THE HIGH TEMP FORECAST MORE
CHALLENGING...AS THE WEDGE AIRMASS RESULTING FROM LIGHT PRECIP
FALLING INTO THE DRY SURFACE RIDGE SHOULD BE SHALLOW..ON
THE ORDER OF 1000FT. THE WARM ADVECTION ABOVE THE INVERSION SHOULD
INITIALLY HELP TO STRENGTHEN THE WEDGE AIRMASS...BUT FORECAST
SOUNDINGS DO SHOW SOME TOP-DOWN EROSION BEGINNING THIS
AFTERNOON....AND THE SOURCE OF DRY NORTHEASTERLY FLOW WILL BE LOST
AS THE PARENT HIGH SHIFTS OFF THE NEW ENGLAND COAST LATER TODAY.
THE CHALLENGING QUESTION IS HOW QUICKLY THE WEDGE FRONT WILL MIX
NORTH AND WEST ACROSS THE AREA. MODELS HAVE TRENDED SLIGHTLY MORE
AGGRESSIVE WITH THE MIXING...POSSIBLY DUE TO A BETTER HANDLE ON THE
MEAGER QPF EXPECTED THIS MORNING. WILL STILL SHOW A RANGE OF 50-86
FROM NORTHWEST TO SOUTHEAST...BUT THE STRONGEST TEMP GRADIENT THIS
AFTERNOON MAY LIE CLOSER TO THE TRIAD AND AREAS ALONG US HWY MAY BE
2-4 DEGREES WARMER THAN PREVIOUSLY FORECAST.
THE COVERAGE OF LIGHT RAIN WILL DECREASE LATE THIS AFTERNOON AND
SHOULD TRANSITION TO ONLY DRIZZLE OVER THE NORTHWEST PIEDMONT BY
00Z. DRYING ALOFT SHOULD ALLOW AREAS OF (DENSE)FOG TO FORM TONIGHT
WHERE WINDS ARE LIGHTEST...WITH THE HIGHEST SREF PROBABILITY WITHIN
THE REMNANT WEDGE AIRMASS. LOWS IN THE UPPER 40S TO MID 50S.
&&
.SHORT TERM /SATURDAY THROUGH SUNDAY NIGHT/...
AS OF 310 AM FRIDAY...
SATURDAY/SATURDAY NIGHT...
IF THE LINGERING...SHALLOW WEDGE AIRMASS IS INDEED CONFINED TO ONLY
THE FAR NORTHWEST PIEDMONT BY SATURDAY MORNING...THEN MOST OF THE
CWA WILL HAVE LITTLE TROUBLE BREAKING OUT AS A STRONG DEEP LAYER
RIDGE BUILDS BACK ACROSS THE SOUTHEAST US. MODELS DO SHOW SOME
LINGERING MOISTURE IN THE 850-700MB LAYER...SO A FAIR AMOUNT IF
CLOUD COVER WILL KEEP HIGHS FROM REACHING THEIR FULL HEATING
POTENTIAL AS THICKNESSES SOAR WELL ABOVE 1380M. WILL ERR ON THE
SLIGHTLY COOLER SIDE OF STATISTICAL GUIDANCE..WHICH IS STILL SOLIDLY
IN THE LOW TO MID 70S ACROSS THE CWA. A COLD FRONT WILL BEGIN TO
APPROACH THE APPALACHIANS FROM THE WEST SATURDAY NIGHT. WITH A WEAK
PRESSURE GRADIENT EAST OF THE MOUNTAINS AND LINGERING LOW LEVEL
MOISTURE...STRATUS AND FOG MAY BE ISSUES ONCE AGAIN. LOWS WILL BE
UNSEASONABLY MILD IN THE 50S.
FOR SUNDAY/SUNDAY NIGHT: CONTINUED WARM AND GENERALLY DRY. THE
SURFACE AND MID LEVEL LONGWAVE RIDGE AXIS WILL BE ALIGNED JUST OFF
THE EAST COAST EARLY SUNDAY... WITH A MILD SOUTHWESTERLY SURFACE
FLOW AHEAD OF THE WAVY SURFACE COLD FRONT... EXPECTED TO STRETCH
ALONG THE WEST SLOPES OF THE APPALACHIANS. THE MID LEVEL FLOW FROM
THE SW REMAINS FAIRLY FLAT WITH ANY PERCEPTIBLE PERTURBATIONS
HOLDING WELL TO OUR NORTHWEST... AS SHOULD THE UPPER JET CORE AND
LOW LEVEL JET. WITH A LACK OF MECHANISMS TO FORCE ASCENT OVER
CENTRAL NC AND A FAIRLY LIGHT DIFFLUENT LOW LEVEL FLOW... MOST IF
NOT ALL PRECIP SHOULD HOLD NORTHWEST OF THE CWA THROUGH SUNDAY
NIGHT... AND INDEED THE MODEL CROSS SECTIONS REVEAL AN ANAFRONTAL
STRUCTURE WITH SLOPED ASCENT INTO THE COLD AIR OVER AND WEST OF THE
MOUNTAINS. SREF PROBABILITIES ALSO SHOW SINGLE-DIGIT CHANCES OF
MEASURABLE RAIN IN CENTRAL NC THROUGH SUNDAY NIGHT. LOW LEVEL
THICKNESSES REMAIN NEARLY 70 METERS ABOVE NORMAL... ALTHOUGH THIS
LAYER DOES ENCOMPASS A PORTION OF THE WARM NOSE ALOFT AND THUS
SOMEWHAT OVERREPRESENTS THE SURFACE WARMTH. THAT SAID... PREDICTED
925 MB TEMPS OF +15C TO +16C DO SUPPORT HIGHS INTO THE LOWER-MID
70S. FACTORING IN AT LEAST PARTLY CLOUDY SKIES WITH FLAT STRATOCU...
AND CONSIDERING THE MODEL DIFFERENCES WITH THE GFS CLOUDIER AND
COOLER IN THE WEST... EXPECT HIGHS TO RANGE FROM 71 NORTHWEST TO 76
IN THE EAST... LIKELY JUST SHY OF THE RECORD HIGHS. EXPECT AREAS OF
FOG AND LOW STRATUS SUNDAY NIGHT... AND THIS PLUS THE STEADY SW
BREEZE OVERNIGHT SHOULD KEEP TEMPS QUITE MILD OVERNIGHT... DROPPING
NO LOWER THAN 54-58... IN ACCORDANCE WITH LOCAL RESEARCH SHOWING
THAT STATISTICAL GUIDANCE LOWS IN PREFRONTAL WARM-ADVECTION
SCENARIOS ARE OFTEN TOO COOL. -GIH
&&
.LONG TERM /MONDAY THROUGH THURSDAY/...
AS OF 255 AM FRIDAY...
A PATTERN CHANGE IS IN THE OFFING FOR NC THIS WEEK... AS THE RECENT
AND UPCOMING WARM PATTERN WILL BE SUPPLANTED BY AN INFLUX OF COLDER
CANADIAN-SOURCE AIR.
FOR MONDAY/MONDAY NIGHT: HEWING CLOSELY TO THE ECMWF SOLUTION...
WHICH AGREES FAIRLY WELL WITH BOTH THE EC AND GFS ENSEMBLE MEAN...
EXPECT ONE MORE MILD DAY. HOWEVER... THE STEADY SUCCESSION OF
WEAKENING WAVES TRACKING NE UP THE WEST SIDE OF THE RIDGE THROUGH
THE GREAT LAKES COMBINED WITH THE SSE DROP OF THE POLAR VORTEX FROM
NUNAVUT INTO HUDSON BAY WILL HELP SLIGHTLY TILT AND WEAKEN THE WRN
ATLANTIC RIDGE... SUCH THAT THE SURFACE FRONT WILL ALSO PIVOT MORE
SW-TO-NE AND INCH INTO WRN AND NW NC BY LATE MONDAY NIGHT... LEADING
TO IMPROVING RAIN CHANCES THERE. THE ECMWF HAS BEEN A BIT SLOWER AND
THUS DRIER THROUGH MONDAY NIGHT AS COMPARED TO THE GFS... HOWEVER
THE ECMWF HAS BEEN TRENDING A LITTLE FASTER AND ITS MOST RECENT RUN
BRINGS RAIN WELL INTO THE FORECAST AREA LATE AFTERNOON THROUGH THE
NIGHT. WILL CARRY A CHANCE OF SHOWERS... HIGHER OVER THE WRN AND NRN
FRINGE OF THE FORECAST AREA... FROM MIDDAY THROUGH MONDAY NIGHT.
HAVE TRIMMED HIGHS BACK A BIT IN THE NRN/WRN CWA... AND NOW HAVE
HIGHS OF 65-73. WITH EXPECTATIONS OF THE FRONT DIPPING SLIGHTLY PAST
THE NC/VA BORDER AS A BACKDOOR FRONT LATE MONDAY NIGHT AS THE ECMWF
SUGGESTS... WE SHOULD SEE LOWS RANGING FROM NEAR 50 IN THE NORTH TO
THE MID-UPPER 50S SOUTH OF HIGHWAY 64.
FOR TUESDAY/TUESDAY NIGHT: IT APPEARS INCREASINGLY LIKELY THAT THE
BACKDOOR FRONT WILL MAKE GOOD SOUTHWARD PROGRESS WELL INTO NC EARLY
TUESDAY... PROPELLED BY THE COOLER DENSE SURFACE HIGH OVER THE
CENTRAL CONUS AS WELL AS THE STRENGTHENING AND SOUTHWARD EXPANSION
OF THE POLAR VORTEX TO ENVELOP THE ST LAWRENCE VALLEY/GREAT LAKES/
NORTHEAST STATES BY EARLY WEDNESDAY. THE ECMWF TAKES A 25 KT SWRLY
LOW LEVEL JET UP ACROSS CENTRAL/ERN NC... ENHANCING MOIST UPGLIDE
AND SUBSEQUENTLY THE LIFT AND PRECIP OVER CENTRAL NC TUESDAY
AFTERNOON... IN CONJUNCTION WITH INCREASING HIGHER LEVEL LIFT IN THE
RIGHT ENTRANCE REGION OF A 150+ KT JET ACROSS THE NORTHEAST STATES.
WITHOUT GETTING TOO PRECISE IN THE DETAILS WHICH COULD STILL BE OFF
AT THIS TIME RANGE... WILL DEPICT AN INCREASE IN RAIN CHANCES ON
TUESDAY AS THE FRONT DROPS THROUGH. WE MAY IN FACT SEE TEMPS FALLING
DURING THE DAY ESPECIALLY IN THE NORTHERN HALF AS THE RAIN FALLS
INTO THE INCOMING CHILLY AIR MASS. HAVE CUT BACK HIGHS TO RANGE FROM
54 NORTH TO 68 SOUTHEAST... AND EVEN THIS COULD BE TOO WARM IN THE
NORTH. THOSE WITH PLANS ON TUESDAY SHOULD MONITOR OUR LATER
FORECASTS... AS THIS MAY END UP TURNING INTO QUITE A COOL/RAW/CLOUDY
AND POSSIBLY RAINY AFTERNOON. LOWS TUESDAY NIGHT 44-51 AS THE FRONT
DROPS TO OUR SOUTH AND COOLER AIR CONTINUES TO FILTER IN BENEATH
CONSIDERABLE CLOUD COVER.
FOR WEDNESDAY THROUGH THURSDAY: MODELS DIFFER IN THEIR HANDLING OF A
CLOSED LOW EXPECTED TO FORM OVER THE DESERT SOUTHWEST BY TUESDAY.
BOTH THE OPERATIONAL GFS AND ECMWF WEAKEN IT SLIGHTLY AND TAKE IT
EASTWARD INTO THE LOWER MISS VALLEY... WITH THE GFS MORE OF AN OPEN
WAVE AND ABOUT 12 HRS FASTER THAN THE ECMWF. THIS APPROACH WILL TEND
TO FLATTEN OUT THE INITIAL CYCLONIC MID LEVEL FLOW OVER THE MID
SOUTH AND MIDATLANTIC... ALLOWING THE FRONT TO NUDGE A BIT BACK
NORTHWARD TOWARD NC AND POTENTIALLY PROVIDING A FOCUS FOR LIFT ALONG
AND NORTH OF THE FRONT. BUT THERE ARE FAR TOO MANY QUESTION MARKS
REGARDING HOW MUCH MOISTURE WOULD BE AVAILABLE... EXACTLY WHERE THE
FRONT MIGHT END UP DURING THIS TIME FRAME... AND HOW MUCH (IF ANY)
THE POLAR STREAM WILL INFLUENCE THIS PATTERN... CRUCIAL CONSIDERING
THE GFS/ECMWF GREATLY DIVERGE WITH THEIR HANDLING OF THE POLAR
VORTEX. WILL KEEP TEMPS WITHIN A CATEGORY OF NORMAL FOR NOW... WITH
JUST SMALL CHANCE POPS UNTIL THE PICTURE BECOMES MORE CLEAR. -GIH
&&
.AVIATION /06Z FRIDAY THROUGH TUESDAY/...
AS OF 1240 AM FRIDAY...
CURRENT TAF PERIOD...
SOME MVFR CEILINGS ARE NOW BEING REPORTED ACROSS THE SOUTHERN
PORTIONS OF NC...MAINLY IMPACTING TERMINALS FROM KAFP TO KFAY/KCTZ.
LIGHT RAIN HAS SPREAD A LITTLE FURTHER NORTH AND IS APPROACHING
KINT/KGSO...WHERE CEILINGS SHOULD ALSO FALL TO MVFR LEVELS BY 09Z.
AS THE PRECIP CONTINUES TO SPREAD NORTH AND EVENTUALLY NORTHEAST
THIS MORNING...A COOL..MURKY WEDGE AIRMASS IS EXPECTED TO FORM OVER
MUCH OF CENTRAL NC...WITH CEILINGS FALLING TO IFR AND POSSIBLY EVEN
LIFR OVER THE NORTHWEST PIEDMONT. HOWEVER...DUE TO THE VERY LIGHT
NATURE OF THE RAIN...THERE IS IS A CHANCE THAT SOUTHERLY LOW LEVEL
WINDS WILL BE ABLE TO MIX OUT SOME OF THE LOW CLOUDS NEAR KFAY AND
KRWI...LEADING TO MVFR CEILINGS DURING THE AFTERNOON. CONFIDENCE IS
ONLY MODERATE AT THIS POINT AND WILL INCREASE ONCE IT IS MORE CLEAR
HOW STRONG OF A WEDGE AIRMASS DEVELOPS. WITHIN THE
WEDGE...PARTICULARLY AT KGSO AND KINT...LIGHT AND VARIABLE OR
NORTHEASTERLY WINDS CAN BE EXPECTED.
OUTLOOK...
CONDITIONS WILL LIKELY DETERIORATE TO IFR/LIFR IN LOW CEILINGS OR
FOG TONIGHT IN ASSOCIATION WITH A LINGERING COLD AIR DAMMING
WEDGE ACROSS THE AREA. IMPROVEMENT TO MVFR AND EVENTUALLY VFR IS
EXPECTED DURING THE DAY SATURDAY...EARLIEST AT FAY/RWI...FOLLOWED BY
RDU...WITH INT/GSO PERHAPS HANGING ON TO MVFR CEILINGS INTO PORTIONS
OF THE AFTERNOON. SATURDAY NIGHT...EXPECT A CHANCE FOR FOG AT ALL
TAF SITES. VFR CONDITIONS ARE EXPECTED TO PREVAIL ON SUNDAY AND
SUNDAY NIGHT. DETERIORATING CONDITIONS WILL BE POSSIBLE ONCE AGAIN
LATE MONDAY/MONDAY NIGHT.
&&
.CLIMATE...
RECORD TEMPERATURE INFORMATION FOR JANUARY 12/13/14:
JAN 12TH RECORD HIGHS-
RDU: 76 (1890)
GSO: 76 (1907)
FAY: 77 (1916)
JAN 13TH RECORD HIGH MIN TEMPS-
RDU: 61 (2005)
GSO: 61 (1932)
FAY: 59 (2005)
JAN 13TH RECORD HIGHS-
RDU: 78 (2005)
GSO: 76 (1911)
FAY: 79 (2005)
JAN 14TH RECORD HIGH MIN TEMPS-
RDU: 61 (1995)
GSO: 59 (1995)
FAY: 62 (1972)
&&
.RAH WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...HARTFIELD
NEAR TERM...SMITH
SHORT TERM..SMITH/HARTFIELD
LONG TERM...HARTFIELD
AVIATION...SMITH/BSD
CLIMATE...HARTFIELD
AREA FORECAST DISCUSSION
NWS MEDFORD OR
802 PM PST THU JAN 10 2013
.DISCUSSION...COLD...UNSTABLE...AND MOIST NORTHWESTERLY FLOW IS
MAINTAINING SNOW SHOWERS OVER THE WEST SIDE TONIGHT...WITH ONLY
THE LOWEST ELEVATIONS STILL GETTING RAIN AS THE SNOW LEVEL HAS
DECREASED TO AROUND 1000 FEET. A SHARP GRADIENT IN SNOW AMOUNTS
EXISTED TODAY...BASED ON ELEVATION. SNOW TOTALS WEST OF THE
CASCADES HAVE GENERALLY RANGED FROM JUST A TRACE BETWEEN 1000 AND
1500 FEET TO 4 INCHES AROUND 2000 FEET. TONIGHT...SNOW COULD
ACCUMULATE UP TO AN INCH DOWN TO 1000 FEET IN HEAVIER SNOW
SHOWERS...WHILE HIGHER ELEVATIONS COULD SEE A FEW MORE INCHES.
SHORTWAVE TROUGHS ARE MUCH LESS WELL-DEFINED TONIGHT THAN TODAY.
HOWEVER...THE RAP MODEL HAS A HANDLE ON THE NEXT IMPULSE...JUST
OFFSHORE NOW AND EVIDENT BY SOME CLOUD TOP COOLING. SO...ITS
LIKELY THAT SHOWERS WILL CONTINUE OVERNIGHT AS THIS SHORTWAVE
MOVES THROUGH...WITH ADDITIONAL IMPULSES MOVING THROUGH FRIDAY
MORNING. WINTER WEATHER ADVISORIES AT WSWMFR AND FROST/FREEZE
PRODUCTS AT THE COAST AT NPWMFR HAVE BEEN ISSUED. BY FRIDAY NIGHT
THE MODELS SUGGEST ANY SHORTWAVES SHOULD REMAIN OFFSHORE...DECREASING
THE CHANCE FOR SHOWERS FRIDAY NIGHT INTO SATURDAY. IT DOES LOOK
LIKE AFTERNOON WEATHER CONDITIONS FOR TRAVEL WILL IMPROVE
SIGNIFICANTLY SATURDAY AND SUNDAY COMPARED TO FRIDAY`S CONTINUED
SNOW SHOWERS.
EAST OF THE CASCADES...FRESH SNOW PACK AND SOME PARTIAL CLEARING
WILL HELP TEMPERATURES DROP TO SINGLE DIGITS OR NEAR ZERO
TONIGHT. HAVE UPDATED THE GRIDS TO REFLECT THIS IDEA.
PLEASE SEE THE PREVIOUS DISCUSSION FOR MORE DETAILS ON THE WEEKEND
WEATHER AND DRIER CONDITIONS EXPECTED NEXT WEEK.
&&
.AVIATION...ON THE WEST SIDE...COLD AND MOIST ONSHORE FLOW CONTINUES
TO BRING CUMULUS AND SHOWERS FROM THE WATERS IN OVER MUCH OF THE
WEST SIDE TONIGHT. CONDITIONS ARE GENERALLY MVFR, PRIMARILY DUE TO CIG,
OUTSIDE OF SHOWERS, BUT WILL BE OCCASIONALLY REDUCED TO IFR (BOTH
VIS AND CIG) IN SNOW SHOWERS. MOUNTAINS ARE OBSCURED FROM THE
CASCADE CREST WEST AND WILL REMAIN SO THROUGH THIS EVENING...WITH
ISOLATED MOUNTAIN OBSCURATION EAST OF THE CASCADES. CONDITIONS
ARE A MIX OF VFR...IFR...AND MVFR ON THE EAST SIDE AND CALIFORNIA
AS WELL WITH FEWER SNOW SHOWERS. CONDITIONS WILL IMPROVE SOME MOST
AREAS TONIGHT AS SHOWERS DECREASE. HOWEVER, SHOWERS WILL CONTINUE
TO OCCASIONALLY DROP CEILINGS AND VISIBILITY TO IFR THROUGH THE
NIGHT...ESPECIALLY IN UPSLOPE AREAS LIKE THE UMPQUA
DIVIDE...CASCADES...AND SISKIYOUS. AND AS ALWAYS IN A MOIST WINTER
ENVIRONMENT...FOG IN WEST SIDE VALLEYS IS ALWAYS POSSIBLE AS THE
NIGHT WEARS ON.
OCCASIONAL SHOWERS AND A MIX OF VFR AND MVFR CONDITIONS...WITH
ISOLATED AREAS OF IFR...WILL CONTINUE THROUGH FRIDAY MORNING.
MOUNTAIN OBSCURATION WILL CONTINUE TO AFFECT THE ENTIRE FORECAST AREA.
&&
.PREV DISCUSSION... /ISSUED 226 PM PST THU JAN 10 2013/
DISCUSSION...THE LATEST SATELLITE IMAGE SHOWS A SHORTWAVE MOVING
TOWARDS THE OREGON/CALIFORNIA BORDER. THIS FEATURE BROUGHT ENHANCED
SNOW SHOWERS FOR MOST OF THE WESTSIDE FROM ABOUT MID MORNING AND
AFTERNOON. SNOW SHOWERS WILL DECREASE SOME THIS EVENING...BUT
COLD AIR ALOFT REMAINS OVER THE REGION THROUGH FRIDAY WITH A MOIST
NORTH TO NORTHWEST FLOW. SO WE`LL CONTINUE TO HAVE SNOW SHOWERS MOVE
IN FROM THE NORTHWEST TONIGHT WITH MOST ACCUMULATIONS ABOVE 1500
FEET THIS EVENING...THEN 1000 FEET TONIGHT. BECAUSE OF THIS...HAVE
DECIDED TO EXTEND THE SNOW ADVISORIES FOR THE WESTSIDE INTO FRIDAY
MORNING. IN GENERAL...THE ROGUE VALLEY AND UMPQUA BASIN SHOULD GET
LESS THAN AN INCH TONIGHT. NORTHWEST FACING SLOPES OF THE
CASCADES AND SISKIYOUS WILL HAVE HIGHER SNOW ACCUMULATIONS...BUT
IT`S NOT EXPECTED TO BE ENOUGH TO WARRANT ANY WARNINGS OR
ADVISORIES.
SNOW SHOWERS CONTINUE INTO FRIDAY WITH SNOW LEVELS EXPECTED TO COME
UP TO AROUND 2000 FEET IN THE AFTERNOON AND FOR THE MOST PART
SHOWERS WILL BE LIGHT. SO THE CHANCE FOR ACCUMULATING SNOW WILL BE
LOW FRIDAY AFTERNOON. THE NAM AND GFS SHOW A BRIEF BREAK IN THE
WEATHER FRIDAY EVENING...THEN ANOTHER SHORTWAVE MOVES IN FROM THE
NORTH FRIDAY NIGHT. THE MODELS ARE IN SIMILAR AGREEMENT KEEPING MOST
OF THE PRECIPITATION CONFINED TO THE COAST AND MARINE WATERS WHICH
WILL LIMIT THE CONCERN FOR LOW ELEVATION SNOW FOR MOST INLAND
LOCATIONS.
MODELS DIFFER WITH THE NEXT SHORTWAVE SATURDAY...THE GFS CONTINUES
TO BE STRONGER FURTHER WEST....BUT HAS TREND WEAKER AND EAST OVER
THE PAST FEW MODEL RUNS. THE NAM IS WEAKER AND FARTHER EAST WHICH
WILL LIMIT THE AMOUNT OF PRECIPITATION...IF ANY AT ALL. THE EC IS
PRACTICALLY NON-EXISTENT. GIVEN THE GFS HAS TRENDED WEAKER WITH
THIS...TEND TO THINK THE WEATHER AND DRIER SOLUTION IS THE WAY TO
GO. SO HAVE TRENDED POPS AND QPF AMOUNTS DOWN. -PETRUCELLI
EXTENDED...(SUNDAY THROUGH WEDNESDAY)...NORTHERLY FLOW ALOFT
CONTINUES ON SUNDAY, BUT IS BECOMING MORE ANTICYCLONIC AS AN UPPER
LEVEL RIDGE OF HIGH PRESSURE BUILDS TOWARD THE COAST. THIS WILL
RESULT IN DRYING OF THE ATMOSPHERE ALONG WITH DECREASING CHANCES FOR
PRECIPITATION. THE MODELS REMAIN IN GOOD AGREEMENT THAT THE RIDGE
WILL GRADUALLY BUILD OVER THE NORTHEAST PACIFIC AND INTO THE PACIFIC
NORTHWEST FOR THE REMAINDER OF THE PERIOD. THIS WILL RESULT IN DRY
WEATHER THROUGH AT LEAST WEDNESDAY WITH OFF SHORE FLOW IN THE LOW
LEVELS. DESPITE THE OFFSHORE FLOW, THE LOW LEVEL INVERSION WILL BE
PRESENT AND WILL LIKELY LEAD TO LATE NIGHT AND MORNING VALLEY FOG,
AT LEAST ON THE WEST SIDE. -WRIGHT
&&
.MFR WATCHES/WARNINGS/ADVISORIES...
OR...FROST ADVISORY FROM 2 AM TO 8 AM PST FRIDAY FOR ORZ021-022.
WINTER WEATHER ADVISORY UNTIL 10 AM PST FRIDAY ABOVE 1000 FEET
FOR FOR ORZ021-022.
FREEZE WARNING FROM 2 AM TO 8 AM PST FRIDAY FOR ORZ021-022.
WINTER WEATHER ADVISORY UNTIL 10 AM PST FRIDAY ABOVE 1000 FEET
FOR FOR ORZ023.
WINTER WEATHER ADVISORY UNTIL 10 AM PST FRIDAY FOR ORZ025.
WINTER WEATHER ADVISORY UNTIL 10 AM PST FRIDAY FOR ORZ024-026.
CA...NONE.
PACIFIC COASTAL WATERS...SMALL CRAFT ADVISORY FOR WINDS UNTIL 7 AM PST FRIDAY FOR
PZZ350-356.
HAZARDOUS SEAS WARNING UNTIL 4 AM PST FRIDAY FOR PZZ350-356.
SMALL CRAFT ADVISORY FOR WINDS UNTIL 7 AM PST FRIDAY FOR
PZZ370-376.
HAZARDOUS SEAS WARNING UNTIL 4 AM PST FRIDAY FOR PZZ370-376.
$$
NSK/TRW/NSK
AREA FORECAST DISCUSSION
NWS DENVER/BOULDER CO
426 AM MST FRI JAN 11 2013
.SHORT TERM...LATEST RAP QG ANALYSIS SHOWS THE BEST LIFT OVER
CENTRAL COLORADO AT 09Z. ALL OF THE MODELS TAKE THIS OFF TO THE
NORTHEAST DURING THE DAY WITH DECENT SUBSIDENCE MOVING OVERHEAD IN
ITS WAKE. SURFACE CYCLONE IS LOCATED OVER NORTHEAST COLORADO AND
THIS FEATURE IS SCHEDULED TO BOOK OFF TO THE NORTHEAST QUITE
QUICKLY LATER TODAY. PRECIPITATION IS EITHER UNDERWAY AT THIS HOUR
OR WILL SOON BE IN MUCH OF THE HIGH COUNTRY WITH A SEVERAL-HOUR-
LONG BURST OF SNOW EXPECTED DURING THE MORNING HOURS ALONG WITH
SOME BLOWING SNOW. SYNOPTICALLY DRIVEN HIGH COUNTRY SNOW WILL GIVE
WAY TO BETTER OROGRAPHICALLY DRIVEN SNOW AFTER THE TROUGH PASSES.
ADVISORY FOR ZONE 31 LOOKS GOOD FOR THIS. SNOW SHOWERS SHOULD
LINGER THROUGHOUT THE NIGHT AS COLDER AIR FILTERS IN. THE PLAINS
WILL HAVE A SMALL THREAT OF PRECIPITATION AS THE UPPER TROUGH
PASSES BUT THE POSITION OF THE SURFACE CYCLONE AND ITS ATTENDANT
DOWNSLOPE IS NOT IDEAL FOR PLAINS PRECIPITION. AS THIS FEATURE
PULLS TO THE NORTHEAST OVERNIGHT THE FLOW WILL START TO TURN TO
MORE UPSLOPE...BRINGING COLD AIR UP AGAINST THE MOUNTAINS.
MOISTURE SEEMS A BIT SCANT IN THE MODELS BUT THERE WILL PROBABLY
BE ENOUGH AROUND FOR AT LEAST SOME LOWER CLOUDINESS. EVERYONE IS
GOING TO GET COLD TONIGHT WITH SINGLE DIGITS ACROSS THE PLAINS AND
SUBZERO READINGS IN THE HIGH COUNTRY.
.LONG TERM...THE UPPER LEVEL TROUGH AXIS OVER WY...UT AND WESTERN
AZ SATURDAY MORNING WILL MOVE EAST THROUGH THE DAY PASSING OVER
THE STATE. SLIGHTLY COLDER TEMPERATURES WILL FILTER IN THROUGH THE
DAY AND WEAK UPWARD QG VERTICAL VELOCITY WILL PASS OVERHEAD. SOME
MOISTURE WILL STILL BE AVAILABLE TO CONTINUE LIGHT SNOW OVER THE
HIGH MOUNTAINS WITH ANOTHER 2 TO 4 INCHES...WITH THE HIGHEST
AMOUNTS OVER WESTERN JACKSON AND GRAND COUNTIES. A SURFACE HIGH
OVER THE NORTHERN PLAINS WILL BE PUSHING SOUTH TO PRODUCE UPSLOPE
FLOW OVER THE PLAINS WHICH WILL COMBINE WITH THE EXTRA LIFT AND
MOISTURE FOR A SLIGHT CHANCE OF LIGHT SNOW OVER THE URBAN
CORRIDOR DURING SATURDAY AFTERNOON. TEMPERATURES WILL BE IN THE
SINGLE DIGITS IN THE MOUNTAINS AND IN THE TEENS FOR THE PLAINS FOR
HIGHS...THEN BECOME -10 TO -25 IN THE MOUNTAINS AND SINGLE DIGITS
TO BELOW ZERO FOR THE PLAINS SATURDAY NIGHT.
THE AIRMASS WILL BEGIN DRYING OUT BUT REMAINING COLD AS THE
ANOTHER PIECE OF ENERGY MOVING INTO THE UPPER TROUGH FINALLY
BEGINS TO HELP MOVE THE TROUGH OUT OF THE AREA BY MONDAY. THE WELL
BELOW AVERAGE TEMPERATURES WILL HANG AROUND SUNDAY WITH LITTLE TO
NO SNOW EXPECTED FOR THE HIGH COUNTRY.
NORTH TO NORTHEAST FLOW ALOFT WILL TURN NORTH TO NORTHEAST MONDAY
NIGHT THROUGH TUESDAY. TEMPERATURES WILL BE WARMING SLOWLY WITH
SURFACE GRADIENTS TIGHTENING TUESDAY NIGHT AS A LOW MOVES DOWN THE
LEE SIDE OF THE ROCKIES AS HIGH PRESSURE RESIDES OVER THE GREAT
BASIN. THE RESULTING WESTERLY WINDS WILL MOST LIKELY HELP SCOUR
OUT THE COLD AIRMASS. COULD SEE A FEW SNOW SHOWERS OVER THE HIGH
COUNTRY TUESDAY.
WEDNESDAY AND THURSDAY WILL BE IN DRY WEST TO NORTHWESTERLY ZONAL
FLOW WITH NEAR NORMAL TEMPERATURES. THE PRECIPITATION FORECAST
LOOKS GRIM IN THIS FLOW AS THE CLOSEST AREA OF MOISTURE OVER THE
NORTHERN STATES LOOKS LIKE IT WILL KEEP TO THE NORTH.
&&
.AVIATION...WARM SOUTH TO SOUTHWEST SURFACE WINDS EARLY THIS
MORNING WILL GRADUALLY VEER AROUND TO WESTERLY AND INCREASE IN
SPEED AND GUSTINESS AS BORA CONDITIONS DEVELOP BEHIND THE TROUGH
PASSAGE BY LATER THIS MORNING. GUSTY WESTERLIES CAN BE EXPECTED
THROUGHOUT THE LATER MORNING AND AFTERNOON BEFORE TURNING TO NORTH
AND THEN EAST AND DECREASING OVERNIGHT. WITH A SMALL THREAT OF
SHOWER ACTIVITY LOWER CEILINGS AND BRIEF LOWERED VISIBILITIES ARE
A SMALL POSSIBILITY...MAINLY THIS MORNING. SOME STRATUS MAY BE
AROUND LATER TONIGHT BUT IFR CONDITIONS ARE NOT EXPECTED AT THIS
TIME.
&&
.BOU WATCHES/WARNINGS/ADVISORIES...WINTER WEATHER ADVISORY UNTIL
5 AM MST SATURDAY FOR COZ031.
&&
$$
SHORT TERM...ET
LONG TERM....KRIEDERMAN
AVIATION...ET
AREA FORECAST DISCUSSION
NWS COLUMBIA SC
1018 AM EST FRI JAN 11 2013
.SYNOPSIS...
A WEAK WARM FRONT WILL SHIFT NORTH OF THE FORECAST AREA THIS
AFTERNOON. TEMPERATURES THIS WEEKEND INTO EARLY NEXT WEEK WILL
BE WELL ABOVE NORMAL AS AN UPPER RIDGE REMAINS OVER THE AREA. THE
CHANCE FOR RAIN INCREASES DURING THE MIDDLE OF NEXT WEEK AS A SLOW
MOVING COLD FRONT PUSHES INTO THE AREA.
&&
.NEAR TERM /THROUGH TONIGHT/...
LATE THIS MORNING...WARM FRONT STILL SOUTH OF THE REGION AND
SLOW TO MOVE NORTH. THE LONGER IT REMAINS TO THE SOUTH...THE
LONGER THE FOG WILL PERSIST. EXTENDED THE DENSE FOG ADVISORY
THROUGH 11 AM. ISENTROPIC LIFT AND A MID- LEVEL SHORTWAVE TROUGH
SUPPORTS RAIN. RUC MODEL IS SHOWING WEAK SHORT WAVE EMBEDDED IN
UPPER RIDGE THAT IS MOVING THROUGH THE AREA THIS MORNING.
INCREASED POPS TO 40-50 PERCENT NORTH PART WHERE SHORT WAVE CAUSED
SHOWERS TO FORM AND WILL KEEP MAINLY 20 PERCENT ELSEWHERE.
THIS AFTERNOON...WARM FRONT MOVES THROUGH...POPS DROP TO LESS
THAN 20 PERCENT. AS THE WARM FRONT LIFTS NORTH OF THE AREA EXPECT
BREAKS IN THE CLOUDINESS WILL OCCUR LATER TODAY. BECAUSE OF THE
SLOW MOVEMENT OF THE WARM FRONT...LOWERED HIGH TEMPERATURES TO
MIDDLE TO UPPER 60S NORTH TO LOWER TO MIDDLE 70S IN THE SOUTH.
TONIGHT...THE UPPER RIDGE WILL BUILD BACK OVER THE FORECAST AREA
AND UP THE EAST COAST TONIGHT. WITH PLENTY OF LOW LEVEL MOISTURE
EXPECT AREAS OF FOG TO DEVELOP MUCH LIKE THIS MORNING.
&&
.SHORT TERM /SATURDAY THROUGH SUNDAY NIGHT/...
THE UPPER RIDGE WILL BUILD BACK OVER THE FORECAST AREA AND UP THE
EAST COAST SATURDAY AS THE WEST COAST TROUGH DEEPENS ONCE AGAIN.
SURFACE HIGH PRESSURE WILL BE CENTERED OFF THE CAROLINA COAST AND
PROVIDE A WARM SOUTHWESTERLY BOUNDARY LAYER FLOW. THE MAIN PWAT
AXIS AND MOISTURE FLUX TRANSPORT WILL REMAIN OVER THE MISSISSIPPI
AND TENNESSEE VALLEYS THROUGH THE PERIOD AND EXPECT A GENERALLY
DRY FORECAST OVER THE MIDLANDS AND CSRA.
TEMPERATURES WILL BE THE MAIN INTEREST THIS WEEKEND AS LATE SPRING
LIKE TEMPERATURES ARE EXPECTED WITH MAX TEMPS SOME 15-20 DEGREES
ABOVE NORMAL. RECORD HIGH TEMPERATURES WILL BE IN JEOPARDY OF
FALLING BOTH SATURDAY AND SUNDAY ACROSS THE REGION WHILE OVERNIGHT
LOW TEMPERATURES ARE FORECAST TO BE IN THE MID TO UPPER 50S WHICH
IS AROUND WHAT OUR NORMAL HIGH TEMPERATURES ARE THIS TIME OF YEAR.
&&
.LONG TERM /MONDAY THROUGH THURSDAY/...
THE EXTENDED FORECAST FEATURES A HIGHLY AMPLIFIED UPPER PATTERN
EARLY NEXT WEEK WITH A LARGE POSITIVELY TILTED TROUGH ACROSS MUCH
OF THE WESTERN TWO THIRDS OF THE COUNTRY WITH THE UPPER RIDGE AXIS
SHIFTED WELL OFF THE EAST COAST. MONDAY SHOULD BE DRY FOR MOST OF
THE AREA BUT SOME SHOWERS WILL BE POSSIBLE IN THE NORTHERN AND
WESTERN MIDLANDS MONDAY AFTERNOON AS A SLOW MOVING COLD FRONT
WHICH WILL BE FOCUSING FLOODING RAINS OVER THE MISSISSIPPI AND
TENNESSEE VALLEYS DRIFTS SLOWLY EASTWARD TOWARDS THE FORECAST
AREA. TEMPERATURES ON MONDAY WILL AGAIN BE WELL ABOVE NORMAL IN
THE 70S AND LOWS MONDAY NIGHT WILL BE MILD IN THE MID TO UPPER
50S.
AS NORTHERN STREAM ENERGY DROPS INTO THE LONGWAVE TROUGH BY
TUESDAY...HEIGHTS WILL FALL OVER THE FORECAST AREA AND THE FRONT
WILL GRADUALLY MOVE INTO THE AREA. THE FRONT WILL BE SLOW TO PUSH
ACROSS THE REGION DUE TO ITS NEARLY PARALLEL ORIENTATION TO THE
UPPER FLOW AND THIS WILL BRING INCREASED CHANCES OF RAIN TUESDAY
AND WEDNESDAY WITH THE FRONTAL BOUNDARY NEARBY. HAVE INCREASED
POPS A BIT INTO THE HIGHER CHANCE RANGE TUESDAY THROUGH
WEDNESDAY...AND THEY MAY NEED TO BE INCREASED FURTHER ON LATER
SHIFTS...AS MOISTURE TRANSPORT AND PWAT VALUES INCREASE WITHIN THE
FRONTAL ZONE. TEMPERATURES WILL BEGIN TO COOL A BIT BY MID WEEK
BUT WILL LIKELY EXHIBIT A STRONG GRADIENT ACROSS THE FORECAST AREA
ON TUESDAY FROM SOUTHEAST TO NORTHWEST. CONFIDENCE LOWERS LATE IN
THE LONG TERM AS MODEL CONSISTENCY DIMINISHES.
&&
.AVIATION /15Z FRIDAY THROUGH TUESDAY/...
CONVERGENCE ASSOCIATED WITH THE WARM FRONT HAS RESULTED IN STRATUS
AND FOG THIS MORNING. AS THE FRONT LIFTS NORTH OF THE AREA
IMPROVEMENT SHOULD OCCUR. THE GFS AND NAM MOS WERE IN GOOD
AGREEMENT MAINTAINING IFR CONDITIONS THROUGH THIS MORNING...WITH
MVFR AND VFR CEILINGS DEVELOPING THIS AFTERNOON. DIURNAL COOLING
WITH CONTINUED HIGH LOW-LEVEL MOISTURE SHOULD RESULT IN A RETURN
OF STRATUS AND FOG TONIGHT. USED THE GFS LAMP FOR THE TIMING OF
IFR CONDITIONS.
EXTENDED AVIATION OUTLOOK...THERE WILL LIKELY BE SUFFICIENT
LOW-LEVEL MOISTURE FOR WIDESPREAD MVFR OR IFR CEILINGS AND
VISIBILITIES DURING THE EARLY MORNING HOURS SATURDAY THROUGH
MONDAY. RESTRICTIONS ASSOCIATED WITH A FRONTAL SYSTEM MAY OCCUR
TUESDAY.
&&
.CLIMATE...
RECORD HIGH TEMPERATURE INFORMATION FOR JANUARY 12/13/14:
SATURDAY JAN 12TH RECORD HIGHS...
CAE: 77 (1916)
AGS: 78 (1916)
SUNDAY JAN 13TH RECORD HIGHS...
CAE: 77 (2005)
AGS: 79 (2005)
MONDAY JAN 14TH RECORD HIGHS...
CAE: 80 (1932)
AGS: 84 (1932)
&&
.CAE WATCHES/WARNINGS/ADVISORIES...
SC...DENSE FOG ADVISORY UNTIL 11 AM EST THIS MORNING FOR SCZ015-016-
018-020>022-025>031-035>038-041.
GA...DENSE FOG ADVISORY UNTIL 11 AM EST THIS MORNING FOR GAZ040-
063>065-077.
&&
$$
AREA FORECAST DISCUSSION
NWS COLUMBIA SC
958 AM EST FRI JAN 11 2013
.SYNOPSIS...
A WEAK WARM FRONT WILL SHIFT NORTH OF THE FORECAST AREA THIS
AFTERNOON. TEMPERATURES THIS WEEKEND INTO EARLY NEXT WEEK WILL
BE WELL ABOVE NORMAL AS AN UPPER RIDGE REMAINS OVER THE AREA. THE
CHANCE FOR RAIN INCREASES DURING THE MIDDLE OF NEXT WEEK AS A SLOW
MOVING COLD FRONT PUSHES INTO THE AREA.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
WARM FRONT STILL SOUTH OF THE REGION AND SLOW TO MOVE NORTH.
THE LONGER IT REMAINS TO THE SOUTH...THE LONGER THE FOG WILL
PERSIST. EXTENDED THE DENSE FOG ADVISORY THROUGH 11 AM. OTHERWISE...
FOR LATE THIS MORNING AND THIS AFTERNOON...ISENTROPIC LIFT AND A
MID-LEVEL SHORTWAVE TROUGH SUPPORTS RAIN. RUC MODEL IS SHOWING
WEAK SHORT WAVE EMBEDDED IN UPPER RIDGE THAT IS MOVING THROUGH
THE AREA THIS MORNING. INCREASED POPS TO 40-50 PERCENT NORTH PART
WHERE SHORT WAVE CAUSED SHOWERS TO FORM AND WILL KEEP MAINLY 20
PERCENT ELSEWHERE. AFTER WARM FRONT MOVES THROUGH...POPS THIS
AFTERNOON DROP TO LESS THAN 20 PERCENT. AS THE WARM FRONT LIFTS
NORTH OF THE AREA EXPECT BREAKS IN THE CLOUDINESS WILL OCCUR LATER
TODAY. BECAUSE OF THE SLOW MOVEMENT OF THE WARM FRONT...LOWERED
HIGH TEMPERATURES TO MIDDLE TO UPPER 60S NORTH TO LOWER TO MIDDLE
70S IN THE SOUTH.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH SUNDAY NIGHT/...
THE UPPER RIDGE WILL BUILD BACK OVER THE FORECAST AREA AND UP THE
EAST COAST TONIGHT THROUGH SATURDAY AS THE WEST COAST TROUGH
DEEPENS ONCE AGAIN. SURFACE HIGH PRESSURE WILL BE CENTERED OFF THE
CAROLINA COAST AND PROVIDE A WARM SOUTHWESTERLY BOUNDARY LAYER
FLOW. THE MAIN PWAT AXIS AND MOISTURE FLUX TRANSPORT WILL REMAIN
OVER THE MISSISSIPPI AND TENNESSEE VALLEYS THROUGH THE PERIOD AND
EXPECT A GENERALLY DRY FORECAST OVER THE MIDLANDS AND CSRA.
TEMPERATURES WILL BE THE MAIN INTEREST THIS WEEKEND AS LATE SPRING
LIKE TEMPERATURES ARE EXPECTED WITH MAX TEMPS SOME 15-20 DEGREES
ABOVE NORMAL. RECORD HIGH TEMPERATURES WILL BE IN JEOPARDY OF
FALLING BOTH SATURDAY AND SUNDAY ACROSS THE REGION WHILE OVERNIGHT
LOW TEMPERATURES ARE FORECAST TO BE IN THE MID TO UPPER 50S WHICH
IS AROUND WHAT OUR NORMAL HIGH TEMPERATURES ARE THIS TIME OF YEAR.
&&
.LONG TERM /MONDAY THROUGH THURSDAY/...
THE EXTENDED FORECAST FEATURES A HIGHLY AMPLIFIED UPPER PATTERN
EARLY NEXT WEEK WITH A LARGE POSITIVELY TILTED TROUGH ACROSS MUCH
OF THE WESTERN TWO THIRDS OF THE COUNTRY WITH THE UPPER RIDGE AXIS
SHIFTED WELL OFF THE EAST COAST. MONDAY SHOULD BE DRY FOR MOST OF
THE AREA BUT SOME SHOWERS WILL BE POSSIBLE IN THE NORTHERN AND
WESTERN MIDLANDS MONDAY AFTERNOON AS A SLOW MOVING COLD FRONT
WHICH WILL BE FOCUSING FLOODING RAINS OVER THE MISSISSIPPI AND
TENNESSEE VALLEYS DRIFTS SLOWLY EASTWARD TOWARDS THE FORECAST
AREA. TEMPERATURES ON MONDAY WILL AGAIN BE WELL ABOVE NORMAL IN
THE 70S AND LOWS MONDAY NIGHT WILL BE MILD IN THE MID TO UPPER
50S.
AS NORTHERN STREAM ENERGY DROPS INTO THE LONGWAVE TROUGH BY
TUESDAY...HEIGHTS WILL FALL OVER THE FORECAST AREA AND THE FRONT
WILL GRADUALLY MOVE INTO THE AREA. THE FRONT WILL BE SLOW TO PUSH
ACROSS THE REGION DUE TO ITS NEARLY PARALLEL ORIENTATION TO THE
UPPER FLOW AND THIS WILL BRING INCREASED CHANCES OF RAIN TUESDAY
AND WEDNESDAY WITH THE FRONTAL BOUNDARY NEARBY. HAVE INCREASED
POPS A BIT INTO THE HIGHER CHANCE RANGE TUESDAY THROUGH
WEDNESDAY...AND THEY MAY NEED TO BE INCREASED FURTHER ON LATER
SHIFTS...AS MOISTURE TRANSPORT AND PWAT VALUES INCREASE WITHIN THE
FRONTAL ZONE. TEMPERATURES WILL BEGIN TO COOL A BIT BY MID WEEK
BUT WILL LIKELY EXHIBIT A STRONG GRADIENT ACROSS THE FORECAST AREA
ON TUESDAY FROM SOUTHEAST TO NORTHWEST. CONFIDENCE LOWERS LATE IN
THE LONG TERM AS MODEL CONSISTENCY DIMINISHES.
&&
.AVIATION /15Z FRIDAY THROUGH TUESDAY/...
CONVERGENCE ASSOCIATED WITH THE WARM FRONT HAS RESULTED IN STRATUS
AND FOG THIS MORNING. AS THE FRONT LIFTS NORTH OF THE AREA
IMPROVEMENT SHOULD OCCUR. THE GFS AND NAM MOS WERE IN GOOD
AGREEMENT MAINTAINING IFR CONDITIONS THROUGH THIS MORNING...WITH
MVFR AND VFR CEILINGS DEVELOPING THIS AFTERNOON. DIURNAL COOLING
WITH CONTINUED HIGH LOW-LEVEL MOISTURE SHOULD RESULT IN A RETURN
OF STRATUS AND FOG TONIGHT. USED THE GFS LAMP FOR THE TIMING OF
IFR CONDITIONS.
EXTENDED AVIATION OUTLOOK...THERE WILL LIKELY BE SUFFICIENT
LOW-LEVEL MOISTURE FOR WIDESPREAD MVFR OR IFR CEILINGS AND
VISIBILITIES DURING THE EARLY MORNING HOURS SATURDAY THROUGH
MONDAY. RESTRICTIONS ASSOCIATED WITH A FRONTAL SYSTEM MAY OCCUR
TUESDAY.
&&
.CLIMATE...
RECORD HIGH TEMPERATURE INFORMATION FOR JANUARY 12/13/14:
SATURDAY JAN 12TH RECORD HIGHS...
CAE: 77 (1916)
AGS: 78 (1916)
SUNDAY JAN 13TH RECORD HIGHS...
CAE: 77 (2005)
AGS: 79 (2005)
MONDAY JAN 14TH RECORD HIGHS...
CAE: 80 (1932)
AGS: 84 (1932)
&&
.CAE WATCHES/WARNINGS/ADVISORIES...
SC...DENSE FOG ADVISORY UNTIL 11 AM EST THIS MORNING FOR SCZ015-016-
018-020>022-025>031-035>038-041.
GA...DENSE FOG ADVISORY UNTIL 11 AM EST THIS MORNING FOR GAZ040-
063>065-077.
&&
$$
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
629 AM EST FRI JAN 11 2013
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 545 AM EST FRI JAN 11 2013
WV IMAGERY AND RUC ANALYSIS INDICATED A MID/UPPER LEVEL TROUGH FROM
IDAHO INTO SRN CA AND AZ AND A RIDGE OVER THE ERN CONUS RESULTING IN
SW FLOW FROM THE CENTRAL PLAINS INTO THE NRN GREAT LAKES. ONE
SHORTWAVE TROUGH WAS LIFTING NE FROM CNTRL IL WHILE AN UPSTREAM
SHRTWV WAS MOVING FROM UTAH INTO COLORADO. AT THE SFC...SRLY FLOW
PREVAILED AHEAD OF A BROAD TROUGH EXTENDING FROM NE CO THROUGH CNTRL
SD INTO NW MN. THE BAND OF 295K-300K ISENTROPIC LIFT THAT SUPPORTED
THE BAND OF LIGHT RAIN HAD LIFTED TO THE NORTH AND EAST OF THE CWA
LEAVING A LARGE AREA OF LOW LEVEL MOISTURE AND WEAKER 285K-290K
ISENTROPIC ASCENT(BELOW 850 MB) WHICH SUPPORTED MAINLY PATCHY LIGHT
RAIN OR DRIZZLE. ALTHOUGH 2M TEMPS WERE ABOVE FREEZING ...IN THE 33F
TO 35F AT MOST REPORTING SITES...GROUND TEMPS IN MANY LOCATIONS WERE
STILL AT OR BELOW FREEZING. THE OVERNIGHT RAIN HAS RESULTED IN ICY
SECONDARY ROADS...ESPECIALLY OVER THE HIGHER TERRAIN IN CENTRAL
UPPER MICHIGAN.
TODAY...THE MORE SUBSTANTIAL PCPN ASSOCIATED WITH THE IL SHORTWAVE
WILL PASS WELL TO THE SOUTHEAST OF UPPER MI. HOWEVER...THE MOIST
SRLY FLOW AND CONTINUED WEAK LOW LEVEL ISENTROPIC ASCENT COULD
CONTINUE TO SUPPORT SOME PATCHY LIGHT RAIN AND MAINLY JUST DRIZZLE
BY THIS AFTERNOON. SINCE TEMPS WILL ONLY SLOWLY RISE THIS MORNING
...THE FREEZING RAIN ADVISORY WAS RETAINED THROUGH 12Z.
BY MID TO LATE MORNING...WITH TEMPS INTO THE MID AND UPPER 30S...ANY
LINGERING PROBLEMS WITH ICY ROADS SHOULD DIMINISH.
TONIGHT...MODELS WERE IN GOOD AGREEMENT WITH THE MAIN FEATURES
IMPACTING THE UPPER GREAT LAKES. AS THE CO SHORTWAVE TROUGH LIFTS TO
THE NORTHEAST...A SFC LO IS EXPECTED TO MOVE FROM THE PLAINS TO NE
MN BY 12Z SAT. MODELS INDICATE THAT THE DRY SLOT UNDER THE JET SURGE
WILL DOMINATE...LIMITING PCPN CHANCES TO MAINLY DRIZZLE OR PATCHY
LIGHT RAIN. WITH A STEADY S WIND AND LINGERING LOW CLOUDS...EXPECT
STEADY OR SLOWLY RISING TEMPS THROUGH MUCH OF THE NIGHT AS THE COLD
FRONT ONLY APPROACHES THE FAR WEST BY AROUND 12Z. EXPECT AREAS OF
FOG AWAY FROM THE DOWNSLOPE AREAS NEAR LAKE SUPERIOR WITH MOIST LOW
LEVELS AND MELTING SNOW.
.LONG TERM...(SATURDAY THROUGH THURSDAY)
ISSUED AT 545 AM EST FRI JAN 11 2013
TROF CONTINUES TO AMPLIFY OVER THE WRN CONUS AS PATTERN CHANGE IS
UNDERWAY. TROF WILL SLOWLY PROGRESS E OVER THE NEXT WEEK...THOUGH
WITH UNCERTAIN AMPLITUDE. MEDIUM RANGE GUIDANCE CONTINUES TO SHOW A
STRENGTHENING POLAR VORTEX WITH A GREATLY EXPANDING AND INTENSIFYING
ARCTIC AIR MASS AROUND HUDSON BAY NEXT WEEK. WITH BUILDING HEIGHTS
FORECASTED OVER GREENLAND...THERE SHOULD BE A TENDENCY FOR THE
BITTER COLD AIR TO SLIP INTO THE UPPER LAKES. HOWEVER...WITH PHASE
OF RECENTLY STRENGTHENED MJO FAVORING WARMTH OVER THE ERN CONUS...IT
WILL BE INTERESTING TO SEE HOW FAR S THE REALLY BITTER COLD AIR
SINKS NEXT WEEK IN RESPONSE TO THE DEVELOPING BLOCKING HIGH OVER
GREENLAND. AT LEAST FOR NOW...WOULD STILL BE SKEPTICAL OF ANY MODEL
SOLUTIONS SHOWING 850MB TEMPS NEARING -30C OVER UPPER MI OR SHOWING
ANYTHING MORE THAN A BRIEF INTRUSION OF BITTER COLD AIR GIVEN
COMPETING SIGNALS FOR WARMTH/COLD. SO...FCST WILL CONTINUE TO SHOW A
CONSERVATIVE APPROACH TO THE COLD WITH TEMPS GENERALLY CLOSE TO OR A
LITTLE BLO NORMAL NEXT WEEK. WITH SNOW COVER GETTING THIN IN MANY
AREAS AND NOT LIKELY TO INCREASE MUCH IF AT ALL AWAY FROM THE W AND
WNW WIND LES SNOW BELTS...THERE COULD BE PROBLEMS FOR WATER LINES IF
WE DO SEE ANYTHING MORE THAN JUST A SHORT DURATION OF SEVERE COLD.
AS JUST ALLUDED TO...PATTERN WILL BE A DRY ONE WITH LITTLE CHC FOR
ANY WIDESPREAD SYNOPTIC SNOW...BUT LES WILL BE A PERSISTENT FEATURE
OF THE FCST NEXT WEEK. IT APPEARS WESTERLY WINDS WILL PROBABLY
DOMINATE...PREVENTING MORE WIDESPREAD COVERAGE OF LES IN UPPER MI
MOST DAYS. THE KEWEENAW PENINSULA WILL SEE THE MOST SNOW FROM LES
NEXT WEEK...AND THERE MAY BE FAIRLY SUBSTANTIAL TOTALS FOR THE WEEK
THERE.
BEGINNING SAT...SHORTWAVE/SFC LOW WILL BE IN NE MN AT 12Z. AS SYSTEM
MOVES ENE THRU NRN ONTARIO DURING THE DAY...SHARP COLD FRONT WILL
CROSS UPPER MI. HOWEVER...SINCE STRONGEST DEEP LAYER QVECTOR
CONVERGENCE ACCOMPANYING DISTURBANCE PASSES TO THE N...AXIS OF MID
LEVEL DRY AIR IS FCST TO LINGER AND WILL LIKELY LEAD TO A DRY FROPA.
ONLY EXCEPTION MAY BE OVER THE W...CLOSER TO THE PASSING
DYNAMICS/DEEPER MOISTURE AND WHERE THE LOW-LEVEL FLOW WILL TAKE ON
MORE OF A CYCLONIC UPSLOPE COMPONENT...ESPECIALLY IN THE AFTN. 850MB
TEMPS FALLING TO AROUND -15C TOWARD 00Z SUN WILL ALSO ADD AN
INCREASING LES COMPONENT TO THE MIX. WITH WSW LOW-LEVEL WINDS...BEST
CHC FOR INCREASING -SHSN WILL BE OVER THE KEWEENAW. SHARP CAA (MAX
850MB TEMP FALL IS AROUND 10C IN 6HR) AND ISALLOBARIC WIND ALIGNED
WITH GRADIENT WIND (6MB/3HR PRES RISE FOLLOWING FROPA) WILL LEAD TO
WINDY CONDITIONS AFTER FROPA. SW WIND DIRECTION IS NOT TYPICALLY THE
MOST FAVORABLE DIRECTION FOR HIGH WINDS IN MOST LOCATIONS...BUT WITH
850MB WINDS AROUND 45KT...SOME GUSTS COULD APPROACH WIND ADVY
CRITERIA...MAINLY IN THE 1-3HRS DURING THE ISALLOBARIC WIND PUSH.
MOMENTUM TRANSFER SUGGESTS GUSTS OF 30-40MPH SHOULD GENERALLY BE THE
RULE FOR A FEW HRS AFTER FROPA. IN COMBINATION WITH FALLING SFC
TEMPS W TO E THRU THE DAY...THE AIR WILL BEGIN TO FEEL MUCH
COLDER...ESPECIALLY OVER THE W WHERE TEMP FALL WILL BE MOST
SIGNIFICANT.
SAT NIGHT THRU SUN NIGHT...AS COLDER AIR SETTLES INTO THE UPPER
GREAT LAKES...850MB TEMPS FALL INTO THE -16 TO -19C RANGE. LOOKS
LIKE A POTENTIALLY INTERESTING PERIOD OF LES AS GFS/NAM SHOW
MOISTURE PROFILE DEEPENING TO 10KFT OR MORE. WITH DEEP MOISTURE...
DENDRITIC SNOW GROWTH TEMPS FALLING FIRMLY INTO THE CONVECTIVE
LAYER...AND SFC TROF DRIFTING THRU THE AREA...THERE IS AN INCREASING
SIGNAL FOR MDT/HVY LES. SHOULD BE ABLE TO FLUFF UP SOME RATHER
SIGNIFICANT SNOW ACCUMULATIONS AS SNOW TO WATER RATIOS INCREASE TO
20-30 TO 1. THERE IS SOME UNCERTAINTY IN WIND DIRECTION WHICH WON`T
BE HANDLED WELL UNTIL CLOSER TO THE EVENT. OVERALL...MODELS INDICATE
A W TO WSW WIND SAT EVENING AHEAD OF TROF TO SHIFT WNW/NW SUN
MORNING AS SFC TROF PASSES. WITH SFC TROF APPROACHING...WOULD
EXPECT SAT NIGHT WINDS TO HAVE MORE OF A WSW/SW COMPONENT...
ESPECIALLY CONSIDERING LAND BREEZE COMPONENT WHICH SHOULD BE ACTIVE
AS LOW-LEVEL GRADIENT WINDS DIMINISH. THIS COULD LEAD TO A STRONG
CONVERGENCE ZONE/HVY LES SETTING UP FROM AROUND THE APOSTLE ISLANDS
INTO THE KEWEENAW SAT NIGHT. THE MDT/HVY SNOW WOULD THEN EXPAND TO
INCLUDE WNW/NW FAVORED SNOW BELTS FOR A TIME SUN. AT THIS POINT...
THE KEWEENAW PENINSULA APPEARS MOST LIKELY TO BE IMPACTED LONGEST BY
MDT/HVY LES. CONSIDERED A WATCH FOR KEWEENAW/NRN HOUGHTON COUNTIES
BEGINNING SAT NIGHT...BUT WILL LET NEXT SHIFT TAKE ANOTHER LOOK AS
WINDS MAY END UP MORE BACKED SAT NIGHT THAN CURRENTLY EXPECTED AHEAD
OF SFC TROF OR SFC TROF MAY PASS MORE QUICKLY THAN EXPECTED.
MON-THU...MOSTLY WEST WIND LES WILL CONTINUE. WHERE WINDS ARE
EXPECTED TO BE ONSHORE...OPTED FOR LIKELY/CATEGORICAL POPS DURING
THIS PERIOD. TUE IS ONLY DAY THAT MAY END UP DRY ACROSS UPPER MI AS
WINDS MAY BACK SUFFICIENTLY TO SHIFT LES OFFSHORE. OTHERWISE...
MEDIUM RANGE MODELS CONTINUE TO SHOW SIGNIFICANT
TIMING/TRACK/AMPLITUDE DIFFERENCES ON SHORTWAVES DROPPING SE INTO
THE GREAT LAKES NEXT WEEK TO THE S OF THE INTENSIFYING POLAR VORTEX
AROUND HUDSON BAY. ALSO...RUN-TO-RUN CONTINUITY WITH THE SHORTWAVES
REMAINS VERY POOR. SO...THERE`S NOT A LOT OF CONFIDENCE ON THE
SHORTWAVES AFFECTING THE AREA. IF ONE OF THE WAVES CAN AMPLIFY
SUFFICIENTLY...THEN BITTER COLD AIR WOULD PLUNGE INTO THE AREA.
WHETHER THAT HAPPENS REMAINS TO SEEN.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SATURDAY MORNING)
ISSUED AT 628 AM EST FRI JAN 11 2013
ABUNDANT LOW LEVEL MOISTURE WITH SRLY FLOW IS EXPECTED OVER THE
REGION THROUGH THE FORECAST PERIOD. SO...IFR CONDITIONS WILL PERSIST.
THERE MAY BE SOME SLIGHT IMPROVEMENT TO THE CEILINGS THIS
AFTERNOON...BEFORE THE FOG THAT AFFECTS THE SITES TONIGHT MOVES BACK
IN. KSAW SHOULD SEE THE LOWEST CEILINGS/VISIBILITY SINCE THEY WILL
BE MORE SUSCEPTIBLE TO SOUTHERLY UPSLOPE FLOW.
&&
.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 545 AM EST FRI JAN 11 2013
A TIGHT PRESSURE GRADIENT BETWEEN AN APPROACHING LOW PRESSURE TROUGH
FROM THE NRN PLAINS AND A RIDGE OVER THE EASTERN GREAT LAKES WILL
RESULT IN SOUTH TO SOUTHEAST WINDS TO 25 KNOTS ACROSS THE ERN HALF
OF LAKE SUPERIOR THIS MORNING. WINDS SHOULD STAY AT OR BELOW 20 KTS
OVER THE WEST HALF. WINDS WILL DIMINISH BLO 20 KT FRI AFTERNOON AS
PRES GRADIENT WEAKENS.
WITH A WEAK PRES GRADIENT OVER THE LAKE THIS EVENING...EXPECT SSW WINDS
UNDER 20 KTS WINDS. BUT THE WINDS WILL INCREASE OVERNIGHT AS A DEEP
LOW PRESSURE SYSTEM MOVES NE FROM THE PLAINS INTO NE MN AND TIGHTENS
THE GRADIENT. EXPECT THE WINDS TO INCREASE RAPIDLY ON SAT AS A SHARP
COLD FRONT SLICES ACROSS THE UPPER GREAT LAKES AND THE ARRIVAL OF
MUCH COLDER AIR RESULTS IN DECREASING STABILITY AND GREATER MIXING OF
THE STRONGER WINDS TO THE LAKE SURFACE. A GALE WATCH WAS EXPANDED AS
GALES ARE EXPECTED ACROSS THE LAKE FROM SATURDAY MORNING INTO
SATURDAY EVENING. NOT OUT OF THE QUESTION THAT A FEW STORM FORCE
GUSTS COULD OCCUR OVER THE WRN LAKE AS WELL. THE COMBINATION OF THE
STRONG WINDS...COLDER AIR AND HIGHER WAVES WILL RESULT IN FREEZING
SPRAY AS WELL INTO SAT NIGHT WHEN THE WINDS WILL BE DIMINISHING WITH
THE DEPARTURE OF LOW PRES TO THE NORTHEAST. WINDS IN THE 15 TO 25 KT
RANGE ARE EXPECTED SUNDAY INTO MONDAY...BUT THE APPROACH OF ANOTHER
DISTURBANCE LATER ON TUE TUE AND NIGHT MIGHT RESULT IN W-SW WINDS
INCREASING TO GALES.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
FREEZING RAIN ADVISORY UNTIL 7 AM EST /6 AM CST/ THIS MORNING
FOR MIZ001>007-009>011-084-085.
LAKE SUPERIOR...
GALE WATCH FROM SATURDAY MORNING THROUGH SATURDAY EVENING FOR
LSZ240>246-265>267.
GALE WATCH FROM SATURDAY MORNING THROUGH SATURDAY EVENING FOR
LSZ162-263-264.
LAKE MICHIGAN...
GALE WATCH FROM SATURDAY MORNING THROUGH SATURDAY EVENING FOR
LMZ221-248-250.
&&
$$
SHORT TERM...JLB
LONG TERM...ROLFSON
AVIATION...JLB
MARINE...JLB
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
557 AM EST FRI JAN 11 2013
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 545 AM EST FRI JAN 11 2013
WV IMAGERY AND RUC ANALYSIS INDICATED A MID/UPPER LEVEL TROUGH FROM
IDAHO INTO SRN CA AND AZ AND A RIDGE OVER THE ERN CONUS RESULTING IN
SW FLOW FROM THE CENTRAL PLAINS INTO THE NRN GREAT LAKES. ONE
SHORTWAVE TROUGH WAS LIFTING NE FROM CNTRL IL WHILE AN UPSTREAM
SHRTWV WAS MOVING FROM UTAH INTO COLORADO. AT THE SFC...SRLY FLOW
PREVAILED AHEAD OF A BROAD TROUGH EXTENDING FROM NE CO THROUGH CNTRL
SD INTO NW MN. THE BAND OF 295K-300K ISENTROPIC LIFT THAT SUPPORTED
THE BAND OF LIGHT RAIN HAD LIFTED TO THE NORTH AND EAST OF THE CWA
LEAVING A LARGE AREA OF LOW LEVEL MOISTURE AND WEAKER 285K-290K
ISENTROPIC ASCENT(BELOW 850 MB) WHICH SUPPORTED MAINLY PATCHY LIGHT
RAIN OR DRIZZLE. ALTHOUGH 2M TEMPS WERE ABOVE FREEZING ...IN THE 33F
TO 35F AT MOST REPORTING SITES...GROUND TEMPS IN MANY LOCATIONS WERE
STILL AT OR BELOW FREEZING. THE OVERNIGHT RAIN HAS RESULTED IN ICY
SECONDARY ROADS...ESPECIALLY OVER THE HIGHER TERRAIN IN CENTRAL
UPPER MICHIGAN.
TODAY...THE MORE SUBSTANTIAL PCPN ASSOCIATED WITH THE IL SHORTWAVE
WILL PASS WELL TO THE SOUTHEAST OF UPPER MI. HOWEVER...THE MOIST
SRLY FLOW AND CONTINUED WEAK LOW LEVEL ISENTROPIC ASCENT COULD
CONTINUE TO SUPPORT SOME PATCHY LIGHT RAIN AND MAINLY JUST DRIZZLE
BY THIS AFTERNOON. SINCE TEMPS WILL ONLY SLOWLY RISE THIS MORNING
...THE FREEZING RAIN ADVISORY WAS RETAINED THROUGH 12Z.
BY MID TO LATE MORNING...WITH TEMPS INTO THE MID AND UPPER 30S...ANY
LINGERING PROBLEMS WITH ICY ROADS SHOULD DIMINISH.
TONIGHT...MODELS WERE IN GOOD AGREEMENT WITH THE MAIN FEATURES
IMPACTING THE UPPER GREAT LAKES. AS THE CO SHORTWAVE TROUGH LIFTS TO
THE NORTHEAST...A SFC LO IS EXPECTED TO MOVE FROM THE PLAINS TO NE
MN BY 12Z SAT. MODELS INDICATE THAT THE DRY SLOT UNDER THE JET SURGE
WILL DOMINATE...LIMITING PCPN CHANCES TO MAINLY DRIZZLE OR PATCHY
LIGHT RAIN. WITH A STEADY S WIND AND LINGERING LOW CLOUDS...EXPECT
STEADY OR SLOWLY RISING TEMPS THROUGH MUCH OF THE NIGHT AS THE COLD
FRONT ONLY APPROACHES THE FAR WEST BY AROUND 12Z. EXPECT AREAS OF
FOG AWAY FROM THE DOWNSLOPE AREAS NEAR LAKE SUPERIOR WITH MOIST LOW
LEVELS AND MELTING SNOW.
.LONG TERM...(SATURDAY THROUGH THURSDAY)
ISSUED AT 545 AM EST FRI JAN 11 2013
TROF CONTINUES TO AMPLIFY OVER THE WRN CONUS AS PATTERN CHANGE IS
UNDERWAY. TROF WILL SLOWLY PROGRESS E OVER THE NEXT WEEK...THOUGH
WITH UNCERTAIN AMPLITUDE. MEDIUM RANGE GUIDANCE CONTINUES TO SHOW A
STRENGTHENING POLAR VORTEX WITH A GREATLY EXPANDING AND INTENSIFYING
ARCTIC AIR MASS AROUND HUDSON BAY NEXT WEEK. WITH BUILDING HEIGHTS
FORECASTED OVER GREENLAND...THERE SHOULD BE A TENDENCY FOR THE
BITTER COLD AIR TO SLIP INTO THE UPPER LAKES. HOWEVER...WITH PHASE
OF RECENTLY STRENGTHENED MJO FAVORING WARMTH OVER THE ERN CONUS...IT
WILL BE INTERESTING TO SEE HOW FAR S THE REALLY BITTER COLD AIR
SINKS NEXT WEEK IN RESPONSE TO THE DEVELOPING BLOCKING HIGH OVER
GREENLAND. AT LEAST FOR NOW...WOULD STILL BE SKEPTICAL OF ANY MODEL
SOLUTIONS SHOWING 850MB TEMPS NEARING -30C OVER UPPER MI OR SHOWING
ANYTHING MORE THAN A BRIEF INTRUSION OF BITTER COLD AIR GIVEN
COMPETING SIGNALS FOR WARMTH/COLD. SO...FCST WILL CONTINUE TO SHOW A
CONSERVATIVE APPROACH TO THE COLD WITH TEMPS GENERALLY CLOSE TO OR A
LITTLE BLO NORMAL NEXT WEEK. WITH SNOW COVER GETTING THIN IN MANY
AREAS AND NOT LIKELY TO INCREASE MUCH IF AT ALL AWAY FROM THE W AND
WNW WIND LES SNOW BELTS...THERE COULD BE PROBLEMS FOR WATER LINES IF
WE DO SEE ANYTHING MORE THAN JUST A SHORT DURATION OF SEVERE COLD.
AS JUST ALLUDED TO...PATTERN WILL BE A DRY ONE WITH LITTLE CHC FOR
ANY WIDESPREAD SYNOPTIC SNOW...BUT LES WILL BE A PERSISTENT FEATURE
OF THE FCST NEXT WEEK. IT APPEARS WESTERLY WINDS WILL PROBABLY
DOMINATE...PREVENTING MORE WIDESPREAD COVERAGE OF LES IN UPPER MI
MOST DAYS. THE KEWEENAW PENINSULA WILL SEE THE MOST SNOW FROM LES
NEXT WEEK...AND THERE MAY BE FAIRLY SUBSTANTIAL TOTALS FOR THE WEEK
THERE.
BEGINNING SAT...SHORTWAVE/SFC LOW WILL BE IN NE MN AT 12Z. AS SYSTEM
MOVES ENE THRU NRN ONTARIO DURING THE DAY...SHARP COLD FRONT WILL
CROSS UPPER MI. HOWEVER...SINCE STRONGEST DEEP LAYER QVECTOR
CONVERGENCE ACCOMPANYING DISTURBANCE PASSES TO THE N...AXIS OF MID
LEVEL DRY AIR IS FCST TO LINGER AND WILL LIKELY LEAD TO A DRY FROPA.
ONLY EXCEPTION MAY BE OVER THE W...CLOSER TO THE PASSING
DYNAMICS/DEEPER MOISTURE AND WHERE THE LOW-LEVEL FLOW WILL TAKE ON
MORE OF A CYCLONIC UPSLOPE COMPONENT...ESPECIALLY IN THE AFTN. 850MB
TEMPS FALLING TO AROUND -15C TOWARD 00Z SUN WILL ALSO ADD AN
INCREASING LES COMPONENT TO THE MIX. WITH WSW LOW-LEVEL WINDS...BEST
CHC FOR INCREASING -SHSN WILL BE OVER THE KEWEENAW. SHARP CAA (MAX
850MB TEMP FALL IS AROUND 10C IN 6HR) AND ISALLOBARIC WIND ALIGNED
WITH GRADIENT WIND (6MB/3HR PRES RISE FOLLOWING FROPA) WILL LEAD TO
WINDY CONDITIONS AFTER FROPA. SW WIND DIRECTION IS NOT TYPICALLY THE
MOST FAVORABLE DIRECTION FOR HIGH WINDS IN MOST LOCATIONS...BUT WITH
850MB WINDS AROUND 45KT...SOME GUSTS COULD APPROACH WIND ADVY
CRITERIA...MAINLY IN THE 1-3HRS DURING THE ISALLOBARIC WIND PUSH.
MOMENTUM TRANSFER SUGGESTS GUSTS OF 30-40MPH SHOULD GENERALLY BE THE
RULE FOR A FEW HRS AFTER FROPA. IN COMBINATION WITH FALLING SFC
TEMPS W TO E THRU THE DAY...THE AIR WILL BEGIN TO FEEL MUCH
COLDER...ESPECIALLY OVER THE W WHERE TEMP FALL WILL BE MOST
SIGNIFICANT.
SAT NIGHT THRU SUN NIGHT...AS COLDER AIR SETTLES INTO THE UPPER
GREAT LAKES...850MB TEMPS FALL INTO THE -16 TO -19C RANGE. LOOKS
LIKE A POTENTIALLY INTERESTING PERIOD OF LES AS GFS/NAM SHOW
MOISTURE PROFILE DEEPENING TO 10KFT OR MORE. WITH DEEP MOISTURE...
DENDRITIC SNOW GROWTH TEMPS FALLING FIRMLY INTO THE CONVECTIVE
LAYER...AND SFC TROF DRIFTING THRU THE AREA...THERE IS AN INCREASING
SIGNAL FOR MDT/HVY LES. SHOULD BE ABLE TO FLUFF UP SOME RATHER
SIGNIFICANT SNOW ACCUMULATIONS AS SNOW TO WATER RATIOS INCREASE TO
20-30 TO 1. THERE IS SOME UNCERTAINTY IN WIND DIRECTION WHICH WON`T
BE HANDLED WELL UNTIL CLOSER TO THE EVENT. OVERALL...MODELS INDICATE
A W TO WSW WIND SAT EVENING AHEAD OF TROF TO SHIFT WNW/NW SUN
MORNING AS SFC TROF PASSES. WITH SFC TROF APPROACHING...WOULD
EXPECT SAT NIGHT WINDS TO HAVE MORE OF A WSW/SW COMPONENT...
ESPECIALLY CONSIDERING LAND BREEZE COMPONENT WHICH SHOULD BE ACTIVE
AS LOW-LEVEL GRADIENT WINDS DIMINISH. THIS COULD LEAD TO A STRONG
CONVERGENCE ZONE/HVY LES SETTING UP FROM AROUND THE APOSTLE ISLANDS
INTO THE KEWEENAW SAT NIGHT. THE MDT/HVY SNOW WOULD THEN EXPAND TO
INCLUDE WNW/NW FAVORED SNOW BELTS FOR A TIME SUN. AT THIS POINT...
THE KEWEENAW PENINSULA APPEARS MOST LIKELY TO BE IMPACTED LONGEST BY
MDT/HVY LES. CONSIDERED A WATCH FOR KEWEENAW/NRN HOUGHTON COUNTIES
BEGINNING SAT NIGHT...BUT WILL LET NEXT SHIFT TAKE ANOTHER LOOK AS
WINDS MAY END UP MORE BACKED SAT NIGHT THAN CURRENTLY EXPECTED AHEAD
OF SFC TROF OR SFC TROF MAY PASS MORE QUICKLY THAN EXPECTED.
MON-THU...MOSTLY WEST WIND LES WILL CONTINUE. WHERE WINDS ARE
EXPECTED TO BE ONSHORE...OPTED FOR LIKELY/CATEGORICAL POPS DURING
THIS PERIOD. TUE IS ONLY DAY THAT MAY END UP DRY ACROSS UPPER MI AS
WINDS MAY BACK SUFFICIENTLY TO SHIFT LES OFFSHORE. OTHERWISE...
MEDIUM RANGE MODELS CONTINUE TO SHOW SIGNIFICANT
TIMING/TRACK/AMPLITUDE DIFFERENCES ON SHORTWAVES DROPPING SE INTO
THE GREAT LAKES NEXT WEEK TO THE S OF THE INTENSIFYING POLAR VORTEX
AROUND HUDSON BAY. ALSO...RUN-TO-RUN CONTINUITY WITH THE SHORTWAVES
REMAINS VERY POOR. SO...THERE`S NOT A LOT OF CONFIDENCE ON THE
SHORTWAVES AFFECTING THE AREA. IF ONE OF THE WAVES CAN AMPLIFY
SUFFICIENTLY...THEN BITTER COLD AIR WOULD PLUNGE INTO THE AREA.
WHETHER THAT HAPPENS REMAINS TO SEEN.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z FRIDAY EVENING)
ISSUED AT 635 PM EST THU JAN 10 2013
LINGERING DRY AIR WILL PRODUCE VFR CONDITIONS AT THE TAF SITES FOR
THE FIRST COUPLE OF HOURS. BROAD AREA OF RAIN CURRENTLY MOVING
NORTH THROUGH SOUTHERN WISCONSIN WILL BE MOVE ACROSS UPPER MICHIGAN
LATE THIS EVENING AND OVERNIGHT. THIS WILL DROP CEILINGS TO
IFR DURING THE OVERNIGHT HOURS...WITH SOME SITES AT ALTERNATE
LANDING MINIMUMS. BEHIND THE WAVE OF PRECIPITATION...WARM MOIST AIR
WILL LEAD TO LOW CLOUDS THROUGH THE REST OF THE PERIOD AND ALSO
SOME FOG. EXPECT THE FOG TO HAVE THE LOWEST VISIBILITIES AT KSAW
WITH THE FAVORABLE SSE FLOW INITIALLY AND THEN BACKING TO THE SW.
THERE MAY BE SOME SLIGHT LIFT TO THE CEILINGS ABOVE ALTERNATE
LANDING MINS TOMORROW AFTERNOON...BUT THEY WILL LIKELY GO BACK DOWN
AS THE SUN SETS AND FOG REDEVELOPS.
FINALLY...DID ADD A TEMPO FOR KSAW DURING THE FIRST COUPLE OF HOURS
DUE TO FAVORABLE UPSLOPE FLOW FROM THE CLOUDS FROM THE CLOUDS COMING
OFF LAKE MICHIGAN.
&&
.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 545 AM EST FRI JAN 11 2013
A TIGHT PRESSURE GRADIENT BETWEEN AN APPROACHING LOW PRESSURE TROUGH
FROM THE NRN PLAINS AND A RIDGE OVER THE EASTERN GREAT LAKES WILL
RESULT IN SOUTH TO SOUTHEAST WINDS TO 25 KNOTS ACROSS THE ERN HALF
OF LAKE SUPERIOR THIS MORNING. WINDS SHOULD STAY AT OR BELOW 20 KTS
OVER THE WEST HALF. WINDS WILL DIMINISH BLO 20 KT FRI AFTERNOON AS
PRES GRADIENT WEAKENS.
WITH A WEAK PRES GRADIENT OVER THE LAKE THIS EVENING...EXPECT SSW WINDS
UNDER 20 KTS WINDS. BUT THE WINDS WILL INCREASE OVERNIGHT AS A DEEP
LOW PRESSURE SYSTEM MOVES NE FROM THE PLAINS INTO NE MN AND TIGHTENS
THE GRADIENT. EXPECT THE WINDS TO INCREASE RAPIDLY ON SAT AS A SHARP
COLD FRONT SLICES ACROSS THE UPPER GREAT LAKES AND THE ARRIVAL OF
MUCH COLDER AIR RESULTS IN DECREASING STABILITY AND GREATER MIXING OF
THE STRONGER WINDS TO THE LAKE SURFACE. A GALE WATCH WAS EXPANDED AS
GALES ARE EXPECTED ACROSS THE LAKE FROM SATURDAY MORNING INTO
SATURDAY EVENING. NOT OUT OF THE QUESTION THAT A FEW STORM FORCE
GUSTS COULD OCCUR OVER THE WRN LAKE AS WELL. THE COMBINATION OF THE
STRONG WINDS...COLDER AIR AND HIGHER WAVES WILL RESULT IN FREEZING
SPRAY AS WELL INTO SAT NIGHT WHEN THE WINDS WILL BE DIMINISHING WITH
THE DEPARTURE OF LOW PRES TO THE NORTHEAST. WINDS IN THE 15 TO 25 KT
RANGE ARE EXPECTED SUNDAY INTO MONDAY...BUT THE APPROACH OF ANOTHER
DISTURBANCE LATER ON TUE TUE AND NIGHT MIGHT RESULT IN W-SW WINDS
INCREASING TO GALES.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
FREEZING RAIN ADVISORY UNTIL 7 AM EST /6 AM CST/ THIS MORNING
FOR MIZ001>007-009>011-084-085.
LAKE SUPERIOR...
GALE WATCH FROM SATURDAY MORNING THROUGH SATURDAY EVENING FOR
LSZ240>246-265>267.
GALE WATCH FROM SATURDAY MORNING THROUGH SATURDAY EVENING FOR
LSZ162-263-264.
LAKE MICHIGAN...
GALE WATCH FROM SATURDAY MORNING THROUGH SATURDAY EVENING FOR
LMZ221-248-250.
&&
$$
SHORT TERM...JLB
LONG TERM...ROLFSON
AVIATION...SRF
MARINE...JLB
AREA FORECAST DISCUSSION
NWS RALEIGH NC
730 AM EST FRI JAN 11 2013
.SYNOPSIS...
HIGH PRESSURE EXTENDING ACROSS THE AREA THIS MORNING WILL TODAY. A
WARM FRONT WILL LIFT NORTHWARD ACROSS CENTRAL NC THIS AFTERNOON AND
TONIGHT. HIGH PRESSURE ANCHORED OFF THE GEORGIA-NORTHEAST FLORIDA
COAST WILL BRING SPRING LIKE TEMPERATURES TO THE CAROLINAS THIS
WEEKEND.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 730 AM FRIDAY...
WITHIN AN AMPLIFIED LONGWAVE PATTERN OVER THE CONUS...THE REMNANTS
OF THE UPPER THAT WAS OVER TX YESTERDAY IS NOW LIFTING NORTHEAST
ACROSS THE MID MS RIVER VALLEY REGION...WHILE A 1034MB SURFACE HIGH
OVER NEW ENGLAND EXTENDS SOUTH INTO THE CAROLINAS. STRENGTHENING
LOW LEVEL FLOW ON THE EASTERN FLANK OF THE LLJ OVER TN/KY IS LEADING
TO INCREASING WARM ADVECTION AND ISENTROPIC ACCENT ATOP THE SURFACE
RIDGE AXIS OVER CENTRAL NC THIS MORNING. THE SHALLOW LIFT WILL BE
MAXIMIZED THROUGH 15Z OVER THE WESTERN CWA...SHIFTING AND WEAKENING
TO THE NORTH AND EAST THIS AFTERNOON. MOST OF THE ECHOES CURRENTLY
SHOWING UP ARE NOW STARTING TO REACH THE GROUND...WITH MORE AND MORE
SITES REPORTING LIGHT RAIN OR DRIZZLE. BASED ON RAP SOUNDINGS...
MOISTURE IS MOSTLY FOCUSED BELOW THE FREEZING LEVEL AND EVEN AS THE
AXIS OF DEEPER MOIST AXIS ASSOCIATED WITH THE AFOREMENTIONED
SHORTWAVE SHIFTS EAST ACROSS THE MOUNTAINS THIS MORNING...MOISTURE
NEAR -10C WILL BE VERY LIMITED. THUS...LIKELY POPS FOCUSED OVER THE
WESTERN HALF OF THE CWA WILL MAINLY BE FOR EVERY LIGHT RAIN/DRIZZLE
WITH ONLY A TRACE OR A FEW HUNDREDTHS OF QPF.
THIS LACK OF SIGNIFICANT PRECIP MAKES THE HIGH TEMP FORECAST MORE
CHALLENGING...AS THE WEDGE AIRMASS RESULTING FROM LIGHT PRECIP
FALLING INTO THE DRY SURFACE RIDGE SHOULD BE SHALLOW..ON THE ORDER
OF 1000-2000FT. THE WARM ADVECTION ABOVE THE INVERSION SHOULD
INITIALLY HELP TO STRENGTHEN THE WEDGE AIRMASS...BUT FORECAST
SOUNDINGS DO SHOW SOME TOP-DOWN EROSION BEGINNING THIS
AFTERNOON....AND THE SOURCE OF DRY NORTHEASTERLY FLOW WILL BE LOST
AS THE PARENT HIGH SHIFTS OFF THE NEW ENGLAND COAST LATER TODAY. THE
CHALLENGING QUESTION IS HOW QUICKLY THE WEDGE FRONT WILL MIX NORTH
AND WEST ACROSS THE AREA. WILL STILL SHOW A RANGE OF 50-68 FROM
NORTHWEST TO SOUTHEAST....THOUGH LINGERING PRECIP OVER THE NORTHEAST
PIEDMONT MAY HOLD TEMPS DOWN A LITTLE MORE THAN PREVIOUSLY FORECAST.
THE COVERAGE OF LIGHT RAIN WILL DECREASE LATE THIS AFTERNOON AND
SHOULD TRANSITION TO ONLY DRIZZLE OVER THE NORTHWEST PIEDMONT BY
00Z. DRYING ALOFT SHOULD ALLOW AREAS OF (DENSE)FOG TO FORM TONIGHT
WHERE WINDS ARE LIGHTEST...WITH THE HIGHEST SREF PROBABILITY WITHIN
THE REMNANT WEDGE AIRMASS. LOWS IN THE UPPER 40S TO MID 50S.
&&
.SHORT TERM /SATURDAY THROUGH SUNDAY NIGHT/...
AS OF 310 AM FRIDAY...
SATURDAY/SATURDAY NIGHT...
IF THE LINGERING...SHALLOW WEDGE AIRMASS IS INDEED CONFINED TO ONLY
THE FAR NORTHWEST PIEDMONT BY SATURDAY MORNING...THEN MOST OF THE
CWA WILL HAVE LITTLE TROUBLE BREAKING OUT AS A STRONG DEEP LAYER
RIDGE BUILDS BACK ACROSS THE SOUTHEAST US. MODELS DO SHOW SOME
LINGERING MOISTURE IN THE 850-700MB LAYER...SO A FAIR AMOUNT IF
CLOUD COVER WILL KEEP HIGHS FROM REACHING THEIR FULL HEATING
POTENTIAL AS THICKNESSES SOAR WELL ABOVE 1380M. WILL ERR ON THE
SLIGHTLY COOLER SIDE OF STATISTICAL GUIDANCE..WHICH IS STILL SOLIDLY
IN THE LOW TO MID 70S ACROSS THE CWA. A COLD FRONT WILL BEGIN TO
APPROACH THE APPALACHIANS FROM THE WEST SATURDAY NIGHT. WITH A WEAK
PRESSURE GRADIENT EAST OF THE MOUNTAINS AND LINGERING LOW LEVEL
MOISTURE...STRATUS AND FOG MAY BE ISSUES ONCE AGAIN. LOWS WILL BE
UNSEASONABLY MILD IN THE 50S.
FOR SUNDAY/SUNDAY NIGHT: CONTINUED WARM AND GENERALLY DRY. THE
SURFACE AND MID LEVEL LONGWAVE RIDGE AXIS WILL BE ALIGNED JUST OFF
THE EAST COAST EARLY SUNDAY... WITH A MILD SOUTHWESTERLY SURFACE
FLOW AHEAD OF THE WAVY SURFACE COLD FRONT... EXPECTED TO STRETCH
ALONG THE WEST SLOPES OF THE APPALACHIANS. THE MID LEVEL FLOW FROM
THE SW REMAINS FAIRLY FLAT WITH ANY PERCEPTIBLE PERTURBATIONS
HOLDING WELL TO OUR NORTHWEST... AS SHOULD THE UPPER JET CORE AND
LOW LEVEL JET. WITH A LACK OF MECHANISMS TO FORCE ASCENT OVER
CENTRAL NC AND A FAIRLY LIGHT DIFFLUENT LOW LEVEL FLOW... MOST IF
NOT ALL PRECIP SHOULD HOLD NORTHWEST OF THE CWA THROUGH SUNDAY
NIGHT... AND INDEED THE MODEL CROSS SECTIONS REVEAL AN ANAFRONTAL
STRUCTURE WITH SLOPED ASCENT INTO THE COLD AIR OVER AND WEST OF THE
MOUNTAINS. SREF PROBABILITIES ALSO SHOW SINGLE-DIGIT CHANCES OF
MEASURABLE RAIN IN CENTRAL NC THROUGH SUNDAY NIGHT. LOW LEVEL
THICKNESSES REMAIN NEARLY 70 METERS ABOVE NORMAL... ALTHOUGH THIS
LAYER DOES ENCOMPASS A PORTION OF THE WARM NOSE ALOFT AND THUS
SOMEWHAT OVERREPRESENTS THE SURFACE WARMTH. THAT SAID... PREDICTED
925 MB TEMPS OF +15C TO +16C DO SUPPORT HIGHS INTO THE LOWER-MID
70S. FACTORING IN AT LEAST PARTLY CLOUDY SKIES WITH FLAT STRATOCU...
AND CONSIDERING THE MODEL DIFFERENCES WITH THE GFS CLOUDIER AND
COOLER IN THE WEST... EXPECT HIGHS TO RANGE FROM 71 NORTHWEST TO 76
IN THE EAST... LIKELY JUST SHY OF THE RECORD HIGHS. EXPECT AREAS OF
FOG AND LOW STRATUS SUNDAY NIGHT... AND THIS PLUS THE STEADY SW
BREEZE OVERNIGHT SHOULD KEEP TEMPS QUITE MILD OVERNIGHT... DROPPING
NO LOWER THAN 54-58... IN ACCORDANCE WITH LOCAL RESEARCH SHOWING
THAT STATISTICAL GUIDANCE LOWS IN PREFRONTAL WARM-ADVECTION
SCENARIOS ARE OFTEN TOO COOL. -GIH
&&
.LONG TERM /MONDAY THROUGH THURSDAY/...
AS OF 255 AM FRIDAY...
A PATTERN CHANGE IS IN THE OFFING FOR NC THIS WEEK... AS THE RECENT
AND UPCOMING WARM PATTERN WILL BE SUPPLANTED BY AN INFLUX OF COLDER
CANADIAN-SOURCE AIR.
FOR MONDAY/MONDAY NIGHT: HEWING CLOSELY TO THE ECMWF SOLUTION...
WHICH AGREES FAIRLY WELL WITH BOTH THE EC AND GFS ENSEMBLE MEAN...
EXPECT ONE MORE MILD DAY. HOWEVER... THE STEADY SUCCESSION OF
WEAKENING WAVES TRACKING NE UP THE WEST SIDE OF THE RIDGE THROUGH
THE GREAT LAKES COMBINED WITH THE SSE DROP OF THE POLAR VORTEX FROM
NUNAVUT INTO HUDSON BAY WILL HELP SLIGHTLY TILT AND WEAKEN THE WRN
ATLANTIC RIDGE... SUCH THAT THE SURFACE FRONT WILL ALSO PIVOT MORE
SW-TO-NE AND INCH INTO WRN AND NW NC BY LATE MONDAY NIGHT... LEADING
TO IMPROVING RAIN CHANCES THERE. THE ECMWF HAS BEEN A BIT SLOWER AND
THUS DRIER THROUGH MONDAY NIGHT AS COMPARED TO THE GFS... HOWEVER
THE ECMWF HAS BEEN TRENDING A LITTLE FASTER AND ITS MOST RECENT RUN
BRINGS RAIN WELL INTO THE FORECAST AREA LATE AFTERNOON THROUGH THE
NIGHT. WILL CARRY A CHANCE OF SHOWERS... HIGHER OVER THE WRN AND NRN
FRINGE OF THE FORECAST AREA... FROM MIDDAY THROUGH MONDAY NIGHT.
HAVE TRIMMED HIGHS BACK A BIT IN THE NRN/WRN CWA... AND NOW HAVE
HIGHS OF 65-73. WITH EXPECTATIONS OF THE FRONT DIPPING SLIGHTLY PAST
THE NC/VA BORDER AS A BACKDOOR FRONT LATE MONDAY NIGHT AS THE ECMWF
SUGGESTS... WE SHOULD SEE LOWS RANGING FROM NEAR 50 IN THE NORTH TO
THE MID-UPPER 50S SOUTH OF HIGHWAY 64.
FOR TUESDAY/TUESDAY NIGHT: IT APPEARS INCREASINGLY LIKELY THAT THE
BACKDOOR FRONT WILL MAKE GOOD SOUTHWARD PROGRESS WELL INTO NC EARLY
TUESDAY... PROPELLED BY THE COOLER DENSE SURFACE HIGH OVER THE
CENTRAL CONUS AS WELL AS THE STRENGTHENING AND SOUTHWARD EXPANSION
OF THE POLAR VORTEX TO ENVELOP THE ST LAWRENCE VALLEY/GREAT LAKES/
NORTHEAST STATES BY EARLY WEDNESDAY. THE ECMWF TAKES A 25 KT SWRLY
LOW LEVEL JET UP ACROSS CENTRAL/ERN NC... ENHANCING MOIST UPGLIDE
AND SUBSEQUENTLY THE LIFT AND PRECIP OVER CENTRAL NC TUESDAY
AFTERNOON... IN CONJUNCTION WITH INCREASING HIGHER LEVEL LIFT IN THE
RIGHT ENTRANCE REGION OF A 150+ KT JET ACROSS THE NORTHEAST STATES.
WITHOUT GETTING TOO PRECISE IN THE DETAILS WHICH COULD STILL BE OFF
AT THIS TIME RANGE... WILL DEPICT AN INCREASE IN RAIN CHANCES ON
TUESDAY AS THE FRONT DROPS THROUGH. WE MAY IN FACT SEE TEMPS FALLING
DURING THE DAY ESPECIALLY IN THE NORTHERN HALF AS THE RAIN FALLS
INTO THE INCOMING CHILLY AIR MASS. HAVE CUT BACK HIGHS TO RANGE FROM
54 NORTH TO 68 SOUTHEAST... AND EVEN THIS COULD BE TOO WARM IN THE
NORTH. THOSE WITH PLANS ON TUESDAY SHOULD MONITOR OUR LATER
FORECASTS... AS THIS MAY END UP TURNING INTO QUITE A COOL/RAW/CLOUDY
AND POSSIBLY RAINY AFTERNOON. LOWS TUESDAY NIGHT 44-51 AS THE FRONT
DROPS TO OUR SOUTH AND COOLER AIR CONTINUES TO FILTER IN BENEATH
CONSIDERABLE CLOUD COVER.
FOR WEDNESDAY THROUGH THURSDAY: MODELS DIFFER IN THEIR HANDLING OF A
CLOSED LOW EXPECTED TO FORM OVER THE DESERT SOUTHWEST BY TUESDAY.
BOTH THE OPERATIONAL GFS AND ECMWF WEAKEN IT SLIGHTLY AND TAKE IT
EASTWARD INTO THE LOWER MISS VALLEY... WITH THE GFS MORE OF AN OPEN
WAVE AND ABOUT 12 HRS FASTER THAN THE ECMWF. THIS APPROACH WILL TEND
TO FLATTEN OUT THE INITIAL CYCLONIC MID LEVEL FLOW OVER THE MID
SOUTH AND MIDATLANTIC... ALLOWING THE FRONT TO NUDGE A BIT BACK
NORTHWARD TOWARD NC AND POTENTIALLY PROVIDING A FOCUS FOR LIFT ALONG
AND NORTH OF THE FRONT. BUT THERE ARE FAR TOO MANY QUESTION MARKS
REGARDING HOW MUCH MOISTURE WOULD BE AVAILABLE... EXACTLY WHERE THE
FRONT MIGHT END UP DURING THIS TIME FRAME... AND HOW MUCH (IF ANY)
THE POLAR STREAM WILL INFLUENCE THIS PATTERN... CRUCIAL CONSIDERING
THE GFS/ECMWF GREATLY DIVERGE WITH THEIR HANDLING OF THE POLAR
VORTEX. WILL KEEP TEMPS WITHIN A CATEGORY OF NORMAL FOR NOW... WITH
JUST SMALL CHANCE POPS UNTIL THE PICTURE BECOMES MORE CLEAR. -GIH
&&
.AVIATION /12Z FRIDAY THROUGH TUESDAY/...
AS OF 640 AM FRIDAY...
CURRENT TAF PERIOD...
ADVERSE AVIATION CONDITIONS HAVE DEVELOPED THIS MORNING AS PATCHY
LIGHT RAIN MOVES SOUTH TO NORTH ACROSS CENTRAL NC. CEILINGS VARY
FROM IFR OVER THE WESTERN PIEDMONT TO MVFR TOWARD KRWI AND
KFAY...WITH SOME POCKETS OF MVFR VSBYS IN THE HEAVIER RAIN/DRIZZLE.
AS THE PRECIP CONTINUES TO SPREAD NORTH AND EVENTUALLY NORTHEAST
THIS MORNING...CEILINGS AND VSBYS SHOULD REMAIN FAIRLY UNCHANGED
THROUGH MIDDAY...ALTHOUGH LIFR CEILINGS COULD STILL DEVELOP OVER THE
NORTHWEST PIEDMONT. THERE IS IS A CHANCE THAT SOUTHERLY LOW LEVEL
WINDS WILL BE ABLE TO MIX OUT SOME OF THE LOW CLOUDS NEAR KFAY AND
KRWI...LEADING TO MVFR CEILINGS DURING THE AFTERNOON.
HOWEVER...CONFIDENCE IN THIS HAPPENING IS ONLY MODERATE...WITH MUCH
LOWER CONFIDENCE TO THE WEST AT KRDU. LIGHT AND VARIABLE OR
NORTHEASTERLY WINDS CAN BE EXPECTED AT KGSO/KINT...WITH WINDS
SWITCHING TO SOUTHERLY THIS AFTERNOON AT KFAY AND KRWI. BORDERLINE
LOW LEVEL WIND SHEAR CRITERIA WILL BE POSSIBLE THIS MORNING AT
KGSO/KINT/KRDU. WINDS ARE AROUND 30KT JUST ABOVE 2000 FT...BUT THE
INVERSION MAY NOT YET BE SHARP ENOUGH FOR A 20KT CHANGE OVER 200
FT...EVEN WITH VEERING WIND PROFILES. THE INVERSION IS EXPECTED TO
STREGTHEN BY MIDDAY...THOUGH AT THE SAME TIME WINDS ABOVE THE
SURFACE WEAKEN.
SUB-VFR CEILINGS SHOULD PERSIST OVERNIGHT AND INTO MID-MORNING
SATURDAY. MEANWHILE...AS DRIER AIR ALOFT MOVES ACROSS THE AREA
TONIGHT...AREAS OF FOG ARE LIKELY TO DEVELOP...WITH DENSE FOG AND
POSSIBLE AFTER MIDNIGHT.
OUTLOOK...
WHILE CONDITIONS ARE EXPECTED TO IMPROVE BY MIDDAY SATURDAY...LOW
VSBYS AND CEILINGS WILL BE POSSIBLE AGAIN SATURDAY NIGHT. VFR
CONDITIONS WILL THEN REDEVELOP ON SUNDAY. THE NEXT CHANCE OF
WIDESPREAD SUB-VFR CONDITIONS WILL BE LATE MONDAY THROUGH TUESDAY AS
A COLD FRONT MOVES INTO THE AREA FROM THE WEST.
&&
.CLIMATE...
RECORD TEMPERATURE INFORMATION FOR JANUARY 12/13/14:
JAN 12TH RECORD HIGHS-
RDU: 76 (1890)
GSO: 76 (1907)
FAY: 77 (1916)
JAN 13TH RECORD HIGH MIN TEMPS-
RDU: 61 (2005)
GSO: 61 (1932)
FAY: 59 (2005)
JAN 13TH RECORD HIGHS-
RDU: 78 (2005)
GSO: 76 (1911)
FAY: 79 (2005)
JAN 14TH RECORD HIGH MIN TEMPS-
RDU: 61 (1995)
GSO: 59 (1995)
FAY: 62 (1972)
&&
.RAH WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...HARTFIELD
NEAR TERM...SMITH
SHORT TERM..SMITH/HARTFIELD
LONG TERM...HARTFIELD
AVIATION...SMITH
CLIMATE...HARTFIELD
AREA FORECAST DISCUSSION
NWS RALEIGH NC
650 AM EST FRI JAN 11 2013
.SYNOPSIS...
HIGH PRESSURE EXTENDING ACROSS THE AREA THIS MORNING WILL TODAY. A
WARM FRONT WILL LIFT NORTHWARD ACROSS CENTRAL NC THIS AFTERNOON AND
TONIGHT. HIGH PRESSURE ANCHORED OFF THE GEORGIA-NORTHEAST FLORIDA
COAST WILL BRING SPRING LIKE TEMPERATURES TO THE CAROLINAS THIS
WEEKEND.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 300 AM FRIDAY...
WITHIN AN AMPLIFIED LONGWAVE PATTERN OVER THE CONUS...THE REMNANTS
OF THE UPPER THAT WAS OVER TX YESTERDAY IS NOW LIFTING NORTHEAST
ACROSS THE MID MS RIVER VALLEY REGION...WHILE A 1034MB SURFACE HIGH
OVER NEW ENGLAND EXTENDS SOUTH INTO THE CAROLINAS. STRENGTHENING
LOW LEVEL FLOW ON THE EASTERN FLANK OF THE LLJ OVER TN/KY IS LEADING
TO INCREASING WARM ADVECTION AND ISENTROPIC ACCENT ATOP THE SURFACE
RIDGE AXIS OVER CENTRAL NC THIS MORNING. THE SHALLOW LIFT WILL BE
MAXIMIZED THROUGH 15Z OVER THE WESTERN CWA...SHIFTING AND WEAKENING
TO THE NORTH AND EAST THIS AFTERNOON. MOST OF THE ECHOES CURRENTLY
SHOWING UP ARE NOW STARTING TO REACH THE GROUND...WITH MORE AND MORE
SITES REPORTING LIGHT RAIN OR DRIZZLE. BASED ON RAP SOUNDINGS...
MOISTURE IS MOSTLY FOCUSED BELOW THE FREEZING LEVEL AND EVEN AS THE
AXIS OF DEEPER MOIST AXIS ASSOCIATED WITH THE AFOREMENTIONED
SHORTWAVE SHIFTS EAST ACROSS THE MOUNTAINS THIS MORNING...MOISTURE
NEAR -10C WILL BE VERY LIMITED. THUS...LIKELY POPS FOCUSED OVER THE
WESTERN HALF OF THE CWA WILL MAINLY BE FOR EVERY LIGHT RAIN/DRIZZLE
WITH ONLY A TRACE OR A FEW HUNDREDTHS OF QPF.
THIS LACK OF SIGNIFICANT PRECIP MAKES THE HIGH TEMP FORECAST MORE
CHALLENGING...AS THE WEDGE AIRMASS RESULTING FROM LIGHT PRECIP
FALLING INTO THE DRY SURFACE RIDGE SHOULD BE SHALLOW..ON
THE ORDER OF 1000FT. THE WARM ADVECTION ABOVE THE INVERSION SHOULD
INITIALLY HELP TO STRENGTHEN THE WEDGE AIRMASS...BUT FORECAST
SOUNDINGS DO SHOW SOME TOP-DOWN EROSION BEGINNING THIS
AFTERNOON....AND THE SOURCE OF DRY NORTHEASTERLY FLOW WILL BE LOST
AS THE PARENT HIGH SHIFTS OFF THE NEW ENGLAND COAST LATER TODAY.
THE CHALLENGING QUESTION IS HOW QUICKLY THE WEDGE FRONT WILL MIX
NORTH AND WEST ACROSS THE AREA. MODELS HAVE TRENDED SLIGHTLY MORE
AGGRESSIVE WITH THE MIXING...POSSIBLY DUE TO A BETTER HANDLE ON THE
MEAGER QPF EXPECTED THIS MORNING. WILL STILL SHOW A RANGE OF 50-86
FROM NORTHWEST TO SOUTHEAST...BUT THE STRONGEST TEMP GRADIENT THIS
AFTERNOON MAY LIE CLOSER TO THE TRIAD AND AREAS ALONG US HWY MAY BE
2-4 DEGREES WARMER THAN PREVIOUSLY FORECAST.
THE COVERAGE OF LIGHT RAIN WILL DECREASE LATE THIS AFTERNOON AND
SHOULD TRANSITION TO ONLY DRIZZLE OVER THE NORTHWEST PIEDMONT BY
00Z. DRYING ALOFT SHOULD ALLOW AREAS OF (DENSE)FOG TO FORM TONIGHT
WHERE WINDS ARE LIGHTEST...WITH THE HIGHEST SREF PROBABILITY WITHIN
THE REMNANT WEDGE AIRMASS. LOWS IN THE UPPER 40S TO MID 50S.
&&
.SHORT TERM /SATURDAY THROUGH SUNDAY NIGHT/...
AS OF 310 AM FRIDAY...
SATURDAY/SATURDAY NIGHT...
IF THE LINGERING...SHALLOW WEDGE AIRMASS IS INDEED CONFINED TO ONLY
THE FAR NORTHWEST PIEDMONT BY SATURDAY MORNING...THEN MOST OF THE
CWA WILL HAVE LITTLE TROUBLE BREAKING OUT AS A STRONG DEEP LAYER
RIDGE BUILDS BACK ACROSS THE SOUTHEAST US. MODELS DO SHOW SOME
LINGERING MOISTURE IN THE 850-700MB LAYER...SO A FAIR AMOUNT IF
CLOUD COVER WILL KEEP HIGHS FROM REACHING THEIR FULL HEATING
POTENTIAL AS THICKNESSES SOAR WELL ABOVE 1380M. WILL ERR ON THE
SLIGHTLY COOLER SIDE OF STATISTICAL GUIDANCE..WHICH IS STILL SOLIDLY
IN THE LOW TO MID 70S ACROSS THE CWA. A COLD FRONT WILL BEGIN TO
APPROACH THE APPALACHIANS FROM THE WEST SATURDAY NIGHT. WITH A WEAK
PRESSURE GRADIENT EAST OF THE MOUNTAINS AND LINGERING LOW LEVEL
MOISTURE...STRATUS AND FOG MAY BE ISSUES ONCE AGAIN. LOWS WILL BE
UNSEASONABLY MILD IN THE 50S.
FOR SUNDAY/SUNDAY NIGHT: CONTINUED WARM AND GENERALLY DRY. THE
SURFACE AND MID LEVEL LONGWAVE RIDGE AXIS WILL BE ALIGNED JUST OFF
THE EAST COAST EARLY SUNDAY... WITH A MILD SOUTHWESTERLY SURFACE
FLOW AHEAD OF THE WAVY SURFACE COLD FRONT... EXPECTED TO STRETCH
ALONG THE WEST SLOPES OF THE APPALACHIANS. THE MID LEVEL FLOW FROM
THE SW REMAINS FAIRLY FLAT WITH ANY PERCEPTIBLE PERTURBATIONS
HOLDING WELL TO OUR NORTHWEST... AS SHOULD THE UPPER JET CORE AND
LOW LEVEL JET. WITH A LACK OF MECHANISMS TO FORCE ASCENT OVER
CENTRAL NC AND A FAIRLY LIGHT DIFFLUENT LOW LEVEL FLOW... MOST IF
NOT ALL PRECIP SHOULD HOLD NORTHWEST OF THE CWA THROUGH SUNDAY
NIGHT... AND INDEED THE MODEL CROSS SECTIONS REVEAL AN ANAFRONTAL
STRUCTURE WITH SLOPED ASCENT INTO THE COLD AIR OVER AND WEST OF THE
MOUNTAINS. SREF PROBABILITIES ALSO SHOW SINGLE-DIGIT CHANCES OF
MEASURABLE RAIN IN CENTRAL NC THROUGH SUNDAY NIGHT. LOW LEVEL
THICKNESSES REMAIN NEARLY 70 METERS ABOVE NORMAL... ALTHOUGH THIS
LAYER DOES ENCOMPASS A PORTION OF THE WARM NOSE ALOFT AND THUS
SOMEWHAT OVERREPRESENTS THE SURFACE WARMTH. THAT SAID... PREDICTED
925 MB TEMPS OF +15C TO +16C DO SUPPORT HIGHS INTO THE LOWER-MID
70S. FACTORING IN AT LEAST PARTLY CLOUDY SKIES WITH FLAT STRATOCU...
AND CONSIDERING THE MODEL DIFFERENCES WITH THE GFS CLOUDIER AND
COOLER IN THE WEST... EXPECT HIGHS TO RANGE FROM 71 NORTHWEST TO 76
IN THE EAST... LIKELY JUST SHY OF THE RECORD HIGHS. EXPECT AREAS OF
FOG AND LOW STRATUS SUNDAY NIGHT... AND THIS PLUS THE STEADY SW
BREEZE OVERNIGHT SHOULD KEEP TEMPS QUITE MILD OVERNIGHT... DROPPING
NO LOWER THAN 54-58... IN ACCORDANCE WITH LOCAL RESEARCH SHOWING
THAT STATISTICAL GUIDANCE LOWS IN PREFRONTAL WARM-ADVECTION
SCENARIOS ARE OFTEN TOO COOL. -GIH
&&
.LONG TERM /MONDAY THROUGH THURSDAY/...
AS OF 255 AM FRIDAY...
A PATTERN CHANGE IS IN THE OFFING FOR NC THIS WEEK... AS THE RECENT
AND UPCOMING WARM PATTERN WILL BE SUPPLANTED BY AN INFLUX OF COLDER
CANADIAN-SOURCE AIR.
FOR MONDAY/MONDAY NIGHT: HEWING CLOSELY TO THE ECMWF SOLUTION...
WHICH AGREES FAIRLY WELL WITH BOTH THE EC AND GFS ENSEMBLE MEAN...
EXPECT ONE MORE MILD DAY. HOWEVER... THE STEADY SUCCESSION OF
WEAKENING WAVES TRACKING NE UP THE WEST SIDE OF THE RIDGE THROUGH
THE GREAT LAKES COMBINED WITH THE SSE DROP OF THE POLAR VORTEX FROM
NUNAVUT INTO HUDSON BAY WILL HELP SLIGHTLY TILT AND WEAKEN THE WRN
ATLANTIC RIDGE... SUCH THAT THE SURFACE FRONT WILL ALSO PIVOT MORE
SW-TO-NE AND INCH INTO WRN AND NW NC BY LATE MONDAY NIGHT... LEADING
TO IMPROVING RAIN CHANCES THERE. THE ECMWF HAS BEEN A BIT SLOWER AND
THUS DRIER THROUGH MONDAY NIGHT AS COMPARED TO THE GFS... HOWEVER
THE ECMWF HAS BEEN TRENDING A LITTLE FASTER AND ITS MOST RECENT RUN
BRINGS RAIN WELL INTO THE FORECAST AREA LATE AFTERNOON THROUGH THE
NIGHT. WILL CARRY A CHANCE OF SHOWERS... HIGHER OVER THE WRN AND NRN
FRINGE OF THE FORECAST AREA... FROM MIDDAY THROUGH MONDAY NIGHT.
HAVE TRIMMED HIGHS BACK A BIT IN THE NRN/WRN CWA... AND NOW HAVE
HIGHS OF 65-73. WITH EXPECTATIONS OF THE FRONT DIPPING SLIGHTLY PAST
THE NC/VA BORDER AS A BACKDOOR FRONT LATE MONDAY NIGHT AS THE ECMWF
SUGGESTS... WE SHOULD SEE LOWS RANGING FROM NEAR 50 IN THE NORTH TO
THE MID-UPPER 50S SOUTH OF HIGHWAY 64.
FOR TUESDAY/TUESDAY NIGHT: IT APPEARS INCREASINGLY LIKELY THAT THE
BACKDOOR FRONT WILL MAKE GOOD SOUTHWARD PROGRESS WELL INTO NC EARLY
TUESDAY... PROPELLED BY THE COOLER DENSE SURFACE HIGH OVER THE
CENTRAL CONUS AS WELL AS THE STRENGTHENING AND SOUTHWARD EXPANSION
OF THE POLAR VORTEX TO ENVELOP THE ST LAWRENCE VALLEY/GREAT LAKES/
NORTHEAST STATES BY EARLY WEDNESDAY. THE ECMWF TAKES A 25 KT SWRLY
LOW LEVEL JET UP ACROSS CENTRAL/ERN NC... ENHANCING MOIST UPGLIDE
AND SUBSEQUENTLY THE LIFT AND PRECIP OVER CENTRAL NC TUESDAY
AFTERNOON... IN CONJUNCTION WITH INCREASING HIGHER LEVEL LIFT IN THE
RIGHT ENTRANCE REGION OF A 150+ KT JET ACROSS THE NORTHEAST STATES.
WITHOUT GETTING TOO PRECISE IN THE DETAILS WHICH COULD STILL BE OFF
AT THIS TIME RANGE... WILL DEPICT AN INCREASE IN RAIN CHANCES ON
TUESDAY AS THE FRONT DROPS THROUGH. WE MAY IN FACT SEE TEMPS FALLING
DURING THE DAY ESPECIALLY IN THE NORTHERN HALF AS THE RAIN FALLS
INTO THE INCOMING CHILLY AIR MASS. HAVE CUT BACK HIGHS TO RANGE FROM
54 NORTH TO 68 SOUTHEAST... AND EVEN THIS COULD BE TOO WARM IN THE
NORTH. THOSE WITH PLANS ON TUESDAY SHOULD MONITOR OUR LATER
FORECASTS... AS THIS MAY END UP TURNING INTO QUITE A COOL/RAW/CLOUDY
AND POSSIBLY RAINY AFTERNOON. LOWS TUESDAY NIGHT 44-51 AS THE FRONT
DROPS TO OUR SOUTH AND COOLER AIR CONTINUES TO FILTER IN BENEATH
CONSIDERABLE CLOUD COVER.
FOR WEDNESDAY THROUGH THURSDAY: MODELS DIFFER IN THEIR HANDLING OF A
CLOSED LOW EXPECTED TO FORM OVER THE DESERT SOUTHWEST BY TUESDAY.
BOTH THE OPERATIONAL GFS AND ECMWF WEAKEN IT SLIGHTLY AND TAKE IT
EASTWARD INTO THE LOWER MISS VALLEY... WITH THE GFS MORE OF AN OPEN
WAVE AND ABOUT 12 HRS FASTER THAN THE ECMWF. THIS APPROACH WILL TEND
TO FLATTEN OUT THE INITIAL CYCLONIC MID LEVEL FLOW OVER THE MID
SOUTH AND MIDATLANTIC... ALLOWING THE FRONT TO NUDGE A BIT BACK
NORTHWARD TOWARD NC AND POTENTIALLY PROVIDING A FOCUS FOR LIFT ALONG
AND NORTH OF THE FRONT. BUT THERE ARE FAR TOO MANY QUESTION MARKS
REGARDING HOW MUCH MOISTURE WOULD BE AVAILABLE... EXACTLY WHERE THE
FRONT MIGHT END UP DURING THIS TIME FRAME... AND HOW MUCH (IF ANY)
THE POLAR STREAM WILL INFLUENCE THIS PATTERN... CRUCIAL CONSIDERING
THE GFS/ECMWF GREATLY DIVERGE WITH THEIR HANDLING OF THE POLAR
VORTEX. WILL KEEP TEMPS WITHIN A CATEGORY OF NORMAL FOR NOW... WITH
JUST SMALL CHANCE POPS UNTIL THE PICTURE BECOMES MORE CLEAR. -GIH
&&
.AVIATION /12Z FRIDAY THROUGH TUESDAY/...
AS OF 640 AM FRIDAY...
CURRENT TAF PERIOD...
ADVERSE AVIATION CONDITIONS HAVE DEVELOPED THIS MORNING AS PATCHY
LIGHT RAIN MOVES SOUTH TO NORTH ACROSS CENTRAL NC. CEILINGS VARY
FROM IFR OVER THE WESTERN PIEDMONT TO MVFR TOWARD KRWI AND
KFAY...WITH SOME POCKETS OF MVFR VSBYS IN THE HEAVIER RAIN/DRIZZLE.
AS THE PRECIP CONTINUES TO SPREAD NORTH AND EVENTUALLY NORTHEAST
THIS MORNING...CEILINGS AND VSBYS SHOULD REMAIN FAIRLY UNCHANGED
THROUGH MIDDAY...ALTHOUGH LIFR CEILINGS COULD STILL DEVELOP OVER THE
NORTHWEST PIEDMONT. THERE IS IS A CHANCE THAT SOUTHERLY LOW LEVEL
WINDS WILL BE ABLE TO MIX OUT SOME OF THE LOW CLOUDS NEAR KFAY AND
KRWI...LEADING TO MVFR CEILINGS DURING THE AFTERNOON.
HOWEVER...CONFIDENCE IN THIS HAPPENING IS ONLY MODERATE...WITH MUCH
LOWER CONFIDENCE TO THE WEST AT KRDU. LIGHT AND VARIABLE OR
NORTHEASTERLY WINDS CAN BE EXPECTED AT KGSO/KINT...WITH WINDS
SWITCHING TO SOUTHERLY THIS AFTERNOON AT KFAY AND KRWI.
SUB-VFR CEILINGS SHOULD PERSIST OVERNIGHT AND INTO MID-MORNING
SATURDAY. MEANWHILE...AS DRIER AIR ALOFT MOVES ACROSS THE AREA
TONIGHT...AREAS OF FOG ARE LIKELY TO DEVELOP...WITH DENSE FOG AND
POSSIBLE AFTER MIDNIGHT.
OUTLOOK...
WHILE CONDITIONS ARE EXPECTED TO IMPROVE BY MIDDAY SATURDAY...LOW
VSBYS AND CEILINGS WILL BE POSSIBLE AGAIN SATURDAY NIGHT. VFR
CONDITIONS WILL THEN REDEVELOP ON SUNDAY. THE NEXT CHANCE OF
WIDESPREAD SUB-VFR CONDITIONS WILL BE LATE MONDAY THROUGH TUESDAY AS
A COLD FRONT MOVES INTO THE AREA FROM THE WEST.
&&
.CLIMATE...
RECORD TEMPERATURE INFORMATION FOR JANUARY 12/13/14:
JAN 12TH RECORD HIGHS-
RDU: 76 (1890)
GSO: 76 (1907)
FAY: 77 (1916)
JAN 13TH RECORD HIGH MIN TEMPS-
RDU: 61 (2005)
GSO: 61 (1932)
FAY: 59 (2005)
JAN 13TH RECORD HIGHS-
RDU: 78 (2005)
GSO: 76 (1911)
FAY: 79 (2005)
JAN 14TH RECORD HIGH MIN TEMPS-
RDU: 61 (1995)
GSO: 59 (1995)
FAY: 62 (1972)
&&
.RAH WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...HARTFIELD
NEAR TERM...SMITH
SHORT TERM..SMITH/HARTFIELD
LONG TERM...HARTFIELD
AVIATION...SMITH
CLIMATE...HARTFIELD
AREA FORECAST DISCUSSION
NWS GREENVILLE-SPARTANBURG SC
959 AM EST FRI JAN 11 2013
.SYNOPSIS...
A WARM FRONT WILL GRADUALLY MOVE NORTH OUT OF THE GULF OF MEXICO AND
ACROSS THE AREA OVER THE NEXT FEW DAYS. THIS FRONTAL PASSAGE WILL
PROVIDE THE AREA WITH ABOVE NORMAL TEMPERATURES THROUGH THE WEEKEND.
ANOTHER SLOW MOVING FRONT WILL MOVE ACROSS THE AREA FROM THE WEST
EARLY NEXT WEEK BRINGING BETTER CHANCES OF RAIN AND COOLER
TEMPERATURES.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 955 AM...ANOTHER DAY/ANOTHER COMPLICATED WX PATTERN FOR THE
GSP CWFA. WARM FRONT HAS CROSSED THE SAV RIVER VALLEY WITH AREAS
FROM AND TO GRD INTO THE 60S WITH SLY WINDS. GSP NORTH INTO THE
FOOTHILLS AND I-40 CORRIDOR REMAIN IN THE WEDGE WITH NELY WINDS AND
40S TO 50S. FARTHER EAST THERE APPEARS TO BE A TROF IN PLACE WITH
SELY WINDS AND UPPER 40S TO LOW 50S. 12Z NAM AND LATEST RAP SEEM TO
HAVE PICKED UP ON THESE FEATURES...SO USED MAINLY THOSE MDLS TO
UPDATE THE TEMP/DEW POINT AND WIND GRIDS INTO THE OVERNIGHT HOURS.
THIS KEEPS HIGHS QUITE COOL IN THE HEART OF THE WEDGE WHILE ALLOWING
RISING TEMPS OVER THE TN BORDER COUNTIES...SAV RIVER VALLEY AND THE
SRN AND EASTERN UPSTATE. IF THERE IS ANY DELAY IN THE WARM FRONT OR
IT MOVES FARTHER NORTH OR EAST THAN EXPECTED...THEN ALL THESE TEMPS
COULD BE WRONG. OTHERWISE...HAVE UPDATED TO GO CAT RAIN AND AREAS OF
DRIZZLE MAINLY FROM I-85 NORTH AND WEST THRU THE EARLY AFTERNOON...
THEN TAPER POPS BACK TO THE WEST AS ISENTROPIC LIFT DIMINISHES AS
LOW LEVEL FLOW TURNS SWLY. STILL EXPECT QUITE A BIT OF CLOUDS AROUND
INTO THE OVERNIGHT EVEN WITH DIMINISHING PRECIP.
AS OF DAYBREAK...EXTENSIVE LOW CLOUDS/FOG/DRIZZLE ACROSS THE WESTERN
CAROLINAS AND NORTHEAST GEORGIA. VISIBILITY SHOULD STAY AROUND 1
MILE AT WORST IN MOST PLACES...SO A DENSE FOG ADVISORY IS NOT
ANTICIPATED. THINK UPSLOPE FLOW WILL PRODUCE ENOUGH PRECIPITATION
SIZED HYDROMETEORS THAT WILL SCAVENGE ENOUGH SMALLER DROPLETS TO
KEEP VISIBILITY FROM FALLING BELOW ONE HALF MILE. TEMPS WILL BE
NEARLY STEADY.
FOR TODAY...THE MAIN FEATURE OF INTEREST IS A SHORT WAVE THAT THE
MODELS MOVE ACROSS THE REGION THIS MORNING...FOLLOWED BY A WEAKER
VORT AROUND MIDDAY. THIS FEATURE WAS PARTLY RESPONSIBLE FOR SOME
STRONGER WINDS AT 850MB TRANSLATING ACROSS THE FCST AREA EARLY THIS
MORNING. AS PER USUAL WITH WARM ADVECTION FLOWS...THIS SHOULD NOT
POSE A PROBLEM IN THE MTN VALLEYS...BUT EXPECT SOME STRONGER WINDS
TO PERSIST ON THE RIDGETOPS THROUGH MID MORNING...ALTHO NOT QUITE
ADVISORY LEVEL. THE APPROACH OF THE WAVE SHOULD HELP TO TRIGGER
ADDITIONAL SHOWERS UNTIL ITS PASSAGE LATER THIS MORNING...ESPECIALLY
IN THE STRONG LOW LEVEL UPGLIDE/UPSLOPE FLOW INTO THE SC BLUE RIDGE
AND SRN NC MTNS/UPPER FR BROAD VALLEY. A LIKELY POP STILL LOOKS
APPROPRIATE THERE...FANNING OUT TOWARD THE NW PIEDMONT AS THE WAVE
PASSES THIS MORNING. THE AREA S OF I-85 WILL NOT HAVE THE BENEFIT OF
THE BETTER UPSLOPE AS WIND STARTS TO VEER MORE SW...SO A CHANCE POP
WAS KEPT THERE. TEMPS WILL BE TRICKY TODAY. THE PASSAGE OF THE WAVE
MAY LIFT A WARM FRONTAL BOUNDARY INTO THE FCST AREA THIS
AFTERNOON... AND THIS SEEMS PLAUSIBLE AT LEAST TO AROUND I-85. TEMPS
WERE NUDGED UPWARD NEARLY A CATEGORY IN THESE AREAS. A COOL POOL IS
LIKELY TO PERSIST OVER THE NC FOOTHILLS THOUGH...SO TEMPS WERE KEPT
DOWN IN THE LOW/MID 50S. DEPENDING ON WHERE THE TRANSITION STAYS...
TEMPS COULD BE OFF BY 5 DEGREES OR MORE.
THE FLOW WILL CONTINUE TO GRADUALLY VEER TONIGHT WHICH SHOULD FOCUS
THE WEAK UPSLOPE/UPGLIDE INTO NE GEORGIA AND THE SW MTNS OF NC.
PRECIP CHANCES PARE BACK TO THOSE AREAS THROUGH THE EVENING HOURS AS
MID/UPPER FORCING WILL BE ALMOST NON-EXISTENT. TEMPS SHOULD BE MILD
ONCE AGAIN...GENERALLY A CATEGORY ABOVE OUR NORMAL HIGHS...WITH
PLENTY OF LOW LEVEL MOISTURE. WE MAY DRY OUT ALOFT...WHICH COULD SET
THE STAGE FOR SOME WIDESPREAD DENSE FOG POTENTIAL.
&&
.SHORT TERM /SATURDAY THROUGH SUNDAY NIGHT/...
SATURDAY AND SATURDAY NIGHT...SOUTHWEST FLOW AROUND DEEP SUBTROPICAL
RIDGE OVER THE SE US COAST IMPLIES SOME ISENTROPIC FORCING OVER THE
AREA...BUT AS TEMPERATURES ALOFT WILL ALREADY BE QUITE WARM MODEL
ISENTROPIC OMEGA IS RATHER SMALL. A DECENT AMOUNT OF LOW LEVEL
MOISTURE WILL BE AVAILABLE AND GFS/NAM/SREF ALL DEVELOP SOME PRECIP.
STUDYING THE SPATIAL DISTRIBUTION OF THE PRECIP AND VERY LLVL WINDS
SUGGESTS UPSLOPE WILL BE PRIMARY FORCING. THE SOUTHWEST MTNS ARE
INITIALLY THE FOCUS SAT MRNG...WITH BETTER MOISTURE SHIFTING
NORTHWARD INTO SAT AFTN. WINDS WILL NOT BE ESPECIALLY STRONG NOR WILL
MOISTURE BE PRIME...SO SLIGHT CHANCES ARE APPROPRIATE. AS RIDGE
BEGINS TO BE IMPINGED UPON BY TROUGH ENTERING THE CENTRAL US...WINDS
WILL BACK TO A MORE SOUTHERLY DIRECTION BY SATURDAY EVENING WHICH
WOULD SUGGEST THE BLUE RIDGE ESCARPMENT WOULD BE MOST LIKELY TO SEE
PRECIP AT THAT TIME. HOWEVER LLVL MOISTURE IS NOT SUFFICIENT TO
WARRANT MENTIONABLE POPS AS DRIER AIR IS EVIDENTLY ADVECTED IN FROM
BENEATH THE RIDGE. HIGHS SATURDAY WILL BE QUITE WARM...VERY NEAR OR
BREAKING RECORD HIGHS AT ALL THREE OFFICIAL CLIMATE SITES.
SUNDAY AND SUNDAY NIGHT...MUCH THE SAME STORY UNDER CONTINUING
SOUTHWEST FLOW. HAVE MAINTAINED DRY FCST FOR THE MORNING HOURS...AND
MOST AREAS SHOULD SEE SOME SUNSHINE AT THIS TIME. COLD FRONT LOOKS TO
BE ENTERING WEST TENN AROUND MIDDAY...INCHING EVER CLOSER TO GSP CWFA
THROUGH THE END OF THE SHORT TERM PERIOD...12Z MONDAY. MOISTURE
ADVECTION IS EXPECTED TO IMPROVE BEGINNING SUN AFTN WITH PRECIP
CHANCES INCREASING TO CHANCE IN OUR TN BORDER COUNTIES BY 00Z MONDAY
AND SPREADING EAST/INCREASING FROM THERE. THE FRONT APPEARS TO HAVE
TROUBLE DISLODGING THE INCUMBENT HIGH PRESSURE AND SO THE EASTWARD
EXPANSION OF PRECIP IS FAIRLY SLOW. THE BETTER FRONTOGENETIC/COLD
ADVECTIVE FORCING HAS YET TO REACH THE TN/NC BORDER AT 12Z
MONDAY...BUT MOISTURE IS ABUNDANT BY THAT TIME...SO EVEN THE MODERATE
STRENGTH WARM ADVECTION AHEAD OF THE FRONT SHOULD BE ENOUGH TO
PRODUCE A GOOD BIT OF PRECIP.
PRACTICALLY NO INSTABILITY IS PRESENT IN THE DEEP WARM AIR OVER OUR
REGION DURING THE SHORT TERM...SO THUNDER IS NOT EXPECTED.
&&
.LONG TERM /MONDAY THROUGH THURSDAY/...
AS OF 2 AM EST FRIDAY...THE MEDIUM RANGE FCST BEGINS AT 12Z ON
MONDAY WITH UPPER RIDGING OVER THE SE REGION AND AN EXPANSIVE UPPER
TROF DIGGING DOWN OVER THE WESTERN CONUS. THIS RIDGE WILL BEGIN TO
GRADUALLY FLATTEN ON TUES AS THE TROF SLIDES EASTWARD. THE LONG
RANGE MODELS ARE SUGGESTING THAT A CLOSED H5 LOW WILL DEVELOP OVER
THE SW CONUS BY MID WEEK AND TRACK WESTWARD THRU THE END OF THE
PERIOD. THE ECMWF HAS BEEN GENERATING THIS FEATURE FOR THE PAST FEW
DAYS WHILE THE MORE PROGRESSIVE GFS AND CMC HAVE ARE JUST NOW
BEGINNING TO SPIN OFF THE LOW.
AT THE SURFACE...AN ELONGATED AREA OF LOW LVL FRONTAL CONVERGENCE IS
EXPECTED TO MOVE INTO THE WESTERN CAROLINAS BY THE BEGINNING OF THE
PERIOD MONDAY MORNING. THIS CONVERGENCE ZONE IS EXPECTED TO LINGER
OVER THE FCST AREA FOR THE NEXT 36 TO 48 HRS OR SO AS IT REMAINS
SANDWICHED BETWEEN 2 SFC HIGHS. BY WED EVENING...MODEL SOLUTIONS
CONTINUE TO DIVERGE QUITE A BIT WITH THE GFS DRYING OUT THE CWFA AS
CANADIAN HIGH PRESSURE MOVES IN. THE ECMWF ON THE OTHER HAND...SPINS
UP ANOTHER SFC LOW TO OUR SW ON THURS AND MOVES THE LOW TO OUR SOUTH
LATE THURS AND INTO FRI. THIS SCENARIO KEEPS DEEP MOISTURE OVER THE
MUCH OF THE CWFA ON THURS AND EARLY FRI BEFORE DRYING THINGS OUT FRI
AFTERNOON. THE OVERALL FCST CONSENSUS STILL FAVORS THE ECMWF
SOLUTION AND MAINTAINS AT LEAST A SLIGHT CHANCE POP FOR THURS AND
FRI. OUR WESTERN ZONES SHOULD SEE THE HIGHEST QPF AMOUNTS DURING
DAYS 4 THRU 7 WITH VALUES APPROACHING 2 INCHES OVER FAR WESTERN NC.
TEMPS WILL START OUT WELL ABOVE CLIMO ON MONDAY AND STEADILY DROP
THRU THE PERIOD WITH VALUES STILL REMAINING ABOVE NORMAL BY DAY 7.
&&
.AVIATION /15Z FRIDAY THROUGH TUESDAY/...
AT KCLT...GRIM FCST FOR AVIATION THIS PERIOD. CONDITIONS ARE LIKELY
TO REMAIN IFR OR LOW IFR FOR THE MAJORITY OF THE NEXT 24 HOURS.
CONDITIONAL CLIMATOLOGY AND LAMP GUIDANCE AGREE THAT CEILING WILL
REMAIN IFR THROUGH AT LEAST 18Z. VISIBILITY WILL BE IN AND OUT OF
MVFR/IFR WITH DRIZZLE AND FOG. THINK WE WILL STILL SEE SOME
IMPROVEMENT THIS AFTERNOON AROUND 19Z-21Z WHERE THE VSBY AND CEILING
WILL BECOME MVFR. AS SOON AS THE SUN SETS...EXPECT BOTH TO COME
CRASHING DOWN AGAIN. VERY LOW IFR IS A VERY DISTINCT POSSIBILITY...
BEGINNING AS EARLY AS 03Z. FOR THIS FCST...WILL BRING THEM DOWN ONLY
TO 1 MILE AND OVERCAST 004 BUT THIS COULD EASILY BE BELOW AIRPORT
MINS AFTER 06Z. WIND SHOULD BE GENERALLY ESE THROUGH THE MIDDLE PART
OF THE DAY...BECOMING S OR EVEN SSW IF THE CEILING IMPROVES WITH THE
WARM FRONT LIFTING BRIEFLY N.
ELSEWHERE...VERY SIMILAR TO KCLT. MOST TAF SITES ARE LIKELY TO
REMAIN IFR OR WORSE FOR THE DURATION. ONLY KAND STANDS A DECENT
CHANCE OF IMPROVING TO MVFR LATE THIS AFTERNOON BEFORE COMING BACK
DOWN AGAIN.
OUTLOOK...SOUTHERLY FLOW IS EXPECTED TO MAINTAIN MOISTURE OVER THE
AREA THROUGH THE WEEKEND...RESULTING IN PERIODIC FLIGHT
RESTRICTIONS...ESPECIALLY DURING THE LATE NIGHT/EARLY MORNING HOURS.
PERIODIC LIGHT RAIN WILL ALSO BE POSSIBLE...ESPECIALLY IN AND NEAR
THE MOUNTAINS. RAIN CHANCES MAY INCREASE EARLY NEXT WEEK...AS A COLD
FRONT APPROACHES FROM THE WEST.
AN EXPERIMENTAL AVIATION FORECAST CONSISTENCY TABLE SHOWING THE
PERCENTAGE OF GUIDANCE MEMBERS AGREEING WITH THE SCHEDULED ISSUANCE
CATEGORY IS AVAILABLE AT THE FOLLOWING LINK (USE LOWER CASE)...
WWW.WEATHER.GOV/GSP/AVIATION_TABLES
&&
.CLIMATE...
RECORD HIGH TEMPERATURES FOR SATURDAY...
AVL: 70 IN 1898
CLT: 75 IN 1890
GSP: 70 IN 2000
RECORD HIGH TEMPERATURES FOR SUNDAY...
AVL: 77 IN 1932
CLT: 75 IN 1960
GSP: 79 IN 1911
&&
.GSP WATCHES/WARNINGS/ADVISORIES...
GA...NONE.
NC...NONE.
SC...NONE.
&&
$$
SYNOPSIS...JPT
NEAR TERM...PM/RWH
SHORT TERM...WIMBERLEY
LONG TERM...JPT
AVIATION...PM
CLIMATE...
AREA FORECAST DISCUSSION
NWS DENVER/BOULDER CO
1036 AM MST FRI JAN 11 2013
.UPDATE...A COMPACT SURFACE LOW HAS FORMED OVER THE NORTHEAST
PLAINS CAUSING DOWNSLOPING WINDS ALONG THE FOOTHILLS AND NORTHERLY
WINDS OVER THE I-25 CORRIDOR FROM KCYS DOWN TO KDEN. AN AREA OF
SNOW RELATED TO THE DYNAMIC FORCING ALOFT HAS MOVED OUT OVER FORT
COLLINS AND GREELEY. WITH THE SUPPORT OF THE NORTHERLY SURFACE
WINDS...WE COULD SEE THIS AREA OF SNOW PERSIST THROUGH THE
AFTERNOON ON THE NORTHWEST SIDE OF THE SURFACE LOW. WILL UPDATE
THE FORECAST TO INCREASE THE CHANCE OF SNOW ACROSS THE PLAINS
THROUGH THIS AFTERNOON AND EVENING. WILL ALSO ADD SOME FOG AND
FREEZING DRIZZLE TO THE NORTHEAST CORNER OF THE STATE WHERE
MOISTURE AT THE SURFACE HAS MOVED IN FROM NEBRASKA. AS THE SURFACE
LOW MOVES INTO NEBRASKA THIS AFTERNOON THE FREEZING DRIZZLE WILL
BE REPLACED BY LIGHT SNOW. COLD TEMPERATURES ARE ON THEIR WAY AS
NORTHERLY FLOW ACROSS THE PLAINS INCREASES THROUGH THIS EVENING.
THE REST OF THE FORECAST LOOKS OKAY FOR NOW.
&&
.AVIATION...LOOKS LIKE WINDS WILL BE TRANSITIONING TO NORTHWEST
AND MAYBE NORTHERLY THIS EVENING IN THE WRAP-AROUND TO THE WEST OF
THE SURFACE LOW. WILL INCREASE THE MENTION OF LIGHT SNOW AT DENVER
AREA AIRPORTS THROUGH THE AFTERNOON. CEILINGS WILL DROP INTO MVFR
RANGE...BUT SOME DOWNSLOPE DRYING OFF THE MOUNTAINS SHOULD KEEP
IFR CEILINGS FROM DEVELOPING.
&&
.PREV DISCUSSION... /ISSUED 426 AM MST FRI JAN 11 2013/
SHORT TERM...LATEST RAP QG ANALYSIS SHOWS THE BEST LIFT OVER
CENTRAL COLORADO AT 09Z. ALL OF THE MODELS TAKE THIS OFF TO THE
NORTHEAST DURING THE DAY WITH DECENT SUBSIDENCE MOVING OVERHEAD IN
ITS WAKE. SURFACE CYCLONE IS LOCATED OVER NORTHEAST COLORADO AND
THIS FEATURE IS SCHEDULED TO BOOK OFF TO THE NORTHEAST QUITE
QUICKLY LATER TODAY. PRECIPITATION IS EITHER UNDERWAY AT THIS HOUR
OR WILL SOON BE IN MUCH OF THE HIGH COUNTRY WITH A SEVERAL-HOUR-
LONG BURST OF SNOW EXPECTED DURING THE MORNING HOURS ALONG WITH
SOME BLOWING SNOW. SYNOPTICALLY DRIVEN HIGH COUNTRY SNOW WILL GIVE
WAY TO BETTER OROGRAPHICALLY DRIVEN SNOW AFTER THE TROUGH PASSES.
ADVISORY FOR ZONE 31 LOOKS GOOD FOR THIS. SNOW SHOWERS SHOULD
LINGER THROUGHOUT THE NIGHT AS COLDER AIR FILTERS IN. THE PLAINS
WILL HAVE A SMALL THREAT OF PRECIPITATION AS THE UPPER TROUGH
PASSES BUT THE POSITION OF THE SURFACE CYCLONE AND ITS ATTENDANT
DOWNSLOPE IS NOT IDEAL FOR PLAINS PRECIPITION. AS THIS FEATURE
PULLS TO THE NORTHEAST OVERNIGHT THE FLOW WILL START TO TURN TO
MORE UPSLOPE...BRINGING COLD AIR UP AGAINST THE MOUNTAINS.
MOISTURE SEEMS A BIT SCANT IN THE MODELS BUT THERE WILL PROBABLY
BE ENOUGH AROUND FOR AT LEAST SOME LOWER CLOUDINESS. EVERYONE IS
GOING TO GET COLD TONIGHT WITH SINGLE DIGITS ACROSS THE PLAINS AND
SUBZERO READINGS IN THE HIGH COUNTRY.
LONG TERM...THE UPPER LEVEL TROUGH AXIS OVER WY...UT AND WESTERN
AZ SATURDAY MORNING WILL MOVE EAST THROUGH THE DAY PASSING OVER
THE STATE. SLIGHTLY COLDER TEMPERATURES WILL FILTER IN THROUGH THE
DAY AND WEAK UPWARD QG VERTICAL VELOCITY WILL PASS OVERHEAD. SOME
MOISTURE WILL STILL BE AVAILABLE TO CONTINUE LIGHT SNOW OVER THE
HIGH MOUNTAINS WITH ANOTHER 2 TO 4 INCHES...WITH THE HIGHEST
AMOUNTS OVER WESTERN JACKSON AND GRAND COUNTIES. A SURFACE HIGH
OVER THE NORTHERN PLAINS WILL BE PUSHING SOUTH TO PRODUCE UPSLOPE
FLOW OVER THE PLAINS WHICH WILL COMBINE WITH THE EXTRA LIFT AND
MOISTURE FOR A SLIGHT CHANCE OF LIGHT SNOW OVER THE URBAN
CORRIDOR DURING SATURDAY AFTERNOON. TEMPERATURES WILL BE IN THE
SINGLE DIGITS IN THE MOUNTAINS AND IN THE TEENS FOR THE PLAINS FOR
HIGHS...THEN BECOME -10 TO -25 IN THE MOUNTAINS AND SINGLE DIGITS
TO BELOW ZERO FOR THE PLAINS SATURDAY NIGHT.
THE AIRMASS WILL BEGIN DRYING OUT BUT REMAINING COLD AS THE
ANOTHER PIECE OF ENERGY MOVING INTO THE UPPER TROUGH FINALLY
BEGINS TO HELP MOVE THE TROUGH OUT OF THE AREA BY MONDAY. THE WELL
BELOW AVERAGE TEMPERATURES WILL HANG AROUND SUNDAY WITH LITTLE TO
NO SNOW EXPECTED FOR THE HIGH COUNTRY.
NORTH TO NORTHEAST FLOW ALOFT WILL TURN NORTH TO NORTHEAST MONDAY
NIGHT THROUGH TUESDAY. TEMPERATURES WILL BE WARMING SLOWLY WITH
SURFACE GRADIENTS TIGHTENING TUESDAY NIGHT AS A LOW MOVES DOWN THE
LEE SIDE OF THE ROCKIES AS HIGH PRESSURE RESIDES OVER THE GREAT
BASIN. THE RESULTING WESTERLY WINDS WILL MOST LIKELY HELP SCOUR
OUT THE COLD AIRMASS. COULD SEE A FEW SNOW SHOWERS OVER THE HIGH
COUNTRY TUESDAY.
WEDNESDAY AND THURSDAY WILL BE IN DRY WEST TO NORTHWESTERLY ZONAL
FLOW WITH NEAR NORMAL TEMPERATURES. THE PRECIPITATION FORECAST
LOOKS GRIM IN THIS FLOW AS THE CLOSEST AREA OF MOISTURE OVER THE
NORTHERN STATES LOOKS LIKE IT WILL KEEP TO THE NORTH.
AVIATION...WARM SOUTH TO SOUTHWEST SURFACE WINDS EARLY THIS
MORNING WILL GRADUALLY VEER AROUND TO WESTERLY AND INCREASE IN
SPEED AND GUSTINESS AS BORA CONDITIONS DEVELOP BEHIND THE TROUGH
PASSAGE BY LATER THIS MORNING. GUSTY WESTERLIES CAN BE EXPECTED
THROUGHOUT THE LATER MORNING AND AFTERNOON BEFORE TURNING TO NORTH
AND THEN EAST AND DECREASING OVERNIGHT. WITH A SMALL THREAT OF
SHOWER ACTIVITY LOWER CEILINGS AND BRIEF LOWERED VISIBILITIES ARE
A SMALL POSSIBILITY...MAINLY THIS MORNING. SOME STRATUS MAY BE
AROUND LATER TONIGHT BUT IFR CONDITIONS ARE NOT EXPECTED AT THIS
TIME.
&&
.BOU WATCHES/WARNINGS/ADVISORIES...
WINTER WEATHER ADVISORY UNTIL 5 AM MST SATURDAY FOR COZ031.
&&
$$
SHORT TERM...DANKERS
LONG TERM....99
AVIATION...DANKERS
AREA FORECAST DISCUSSION
NWS QUAD CITIES IA IL
302 PM CST FRI JAN 11 2013
.SYNOPSIS...
12Z UA ANALYSIS HAS A STRONG SYSTEM OVER THE ROCKIES WITH STRONG
SOUTHWEST FLOW FROM NORTHERN MEXICO INTO THE GREAT LAKES.
SATELLITE TRENDS THROUGH MID AFTERNOON INDICATE THE LOW CLOUDS ARE
BREAKING UP AS DEEPER MIXING OCCURS BUT MID AND HIGH LEVEL CLOUDS
ARE STREAMING IN OVER THE REMAINING LOW CLOUDS.
18Z SFC ANALYSIS HAS A LOW NORTH OF KATY WITH ANOTHER NORTHEAST OF
KLIC. A STRONG COLD FRONT CONNECTED BOTH LOWS AND THERE WERE
NUMEROUS TROFS FROM THE GREAT LAKES BACK INTO THE SOUTHERN PLAINS.
DEW POINTS WERE IN THE TEENS AND 20S ACROSS THE NORTHERN PLAINS
WITH 30S AND 40S ACROSS MUCH OF THE GREAT LAKES AND MIDWEST. DEW
POINTS IN THE 50S AND 60S RAN FROM THE OHIO VALLEY INTO THE DEEP
SOUTH.
&&
.SHORT TERM...LATE THIS AFTERNOON THROUGH SATURDAY
WE ARE DEALING WITH ADVECTION FOG. IN ADVECTION FOG YOU CAN HAVE
EXTREMELY DENSE FOG EVEN THOUGH WINDS ARE 10 TO 20 MPH. ALBEIT FAR
FROM PERFECT...THE RAP MODEL TRENDS STRONGLY POINT TO DENSE FOG
CONTINUING INTO THE EVENING ACROSS THE NORTHERN CWFA.
AS FOR HEADLINES...THE DENSE FOG ADVISORY WILL BE EXTENDED UNTIL
MIDNIGHT FROM DUBUQUE ON WEST IN THE HWY 20 CORRIDOR. PER
OBSERVATIONS AND WHAT WEB CAMS ARE AVAILABLE...THE NORTHERN PARTS
OF LINN/JONES/JACKSON COUNTIES IN IOWA AND STEPHENSON COUNTY IN
ILLINOIS STILL HAVE DENSE FOG OVER THEM. THUS THESE COUNTIES AND
JO DAVIESS COUNTY WILL HAVE THE DENSE FOG ADVISORY EXTENDED
THROUGH 6 PM.
THE POSSIBILITY DOES EXIST THAT THE HEADLINES MAY BE DROPPED
EARLY. THAT WILL DEPEND UPON STRONGER WINDS PROMOTING MIXING OF
THE BOUNDARY LAYER TO CAUSE THE FOG TO LIFT.
AFTER MIDNIGHT...A STRONG COLD FRONT WILL SWEEP THROUGH THE CWFA.
THIS FRONT WILL SCOUR OUT WHAT REMAINING FOG IS ACROSS THE AREA.
VERY BRISK CONDITIONS WILL BE SEEN ACROSS THE AREA ON SATURDAY
BEHIND THE FRONT.
THE STRENGTH OF THE CAA ON SATURDAY WOULD NORMALLY RESULT IN
UNSTABLE CONDITIONS WITH CONVECTIVE SHOWERS DEVELOPING. HOWEVER...
LOW LEVEL LAPSE RATES REMAIN QUITE STABLE DURING THE DAY AND FCST
SOUNDINGS SHOW A VERY PRONOUNCED INVERSION ACROSS THE AREA. THUS
SATURDAY WILL REMAIN DRY.
LOW TEMPERATURES TONIGHT WILL OCCUR AROUND 8 AM SATURDAY. THE HIGH
TEMPERATURES FOR THE DAYLIGHT HOURS ON SATURDAY WILL OCCUR BETWEEN
8 AND 10 AM FOLLOWED BY SLOWLY FALLING TEMPERATURES. TEMPERATURES
MAY REBOUND A LITTLE DURING THE AFTERNOON BUT WILL BE BELOW THE
MORNING HIGHS. ..08..
.LONG TERM...SATURDAY NIGHT THROUGH FRIDAY
SATURDAY NIGHT AND SUNDAY TO BE THE TRICKY PERIOD. LAST NIGHT THE
ECMWF TOOK A JOG TO THE NORTHWEST WITH A SHORTWAVE AND SURFACE
LOW THAT MOVES FROM EAST TEXAS NORTHEAST UP THE OHIO VALLEY. IT
APPEARS TO BE BRINGING THE WHOLE FEATURE FARTHER NORTHWEST...AS
WELL AS TAKING ADVANTAGE OF SOME DEEPER FRONTOGENESIS THAT SEEMS
TO BE FORMING ON THE NORTH SIDE OF THE FEATURE. THIS
MORNING...MORE OF THE MODELS FOLLOWED THAT TREND...AND ARE NOW
BRINGING A NICE SWATH OF SNOW TO THE FORECAST AREA. AREAS
SOUTHEAST OF A LINE FROM CEDAR RAPIDS TO DUBUQUE ARE NOW LOOKING
AT A NICE 1 TO POSSIBLY 3 INCH SNOWFALL EVENT...ASSUMING WE CAN
GET ENOUGH MOISTURE INTO THE AREA AND THE ECMWF AND GFS
ISENTROPIC AND FRONTOGENESIS LIFT PROGS ARE CORRECT. HAVE RAISED
POPS...BUT IF THIS TREND CONTINUES WITH TONIGHTS MODEL RUNS...WE
COULD RAISE POPS AGAIN.
SUNDAY NIGHT AND MONDAY TO BE COLD...ESPECIALLY IF WE CAN GET
SOME SNOW ON THE GROUND TO ENHANCE THE STRONG SURFACE RIDGE THAT
WILL BE SITTING OVER THE AREA BY EARLY MONDAY MORNING. AT THIS
TIME IT LOOKS LIKE WE MAY SEE SOME SINGLE DIGITS IN THE NORTHWEST
PORTIONS OF THE FORECAST AREA. IF WE DO GET THE NEW
SNOWPACK...NEARLY THE WHOLE CWA COULD HAVE SINGLE DIGIT MINS WITH
NEAR ZERO VALUES POSSIBLE NORTHWEST. HIGHS ON MONDAY TO STILL BE
CHILLY WITH THE RIDGE STILL OVERHEAD...AND CURRENTLY HAVE MID TO
UPPER 20S.
TUESDAY THE MAIN UPPER LEVEL TROUGH TO SLOWLY MOVE
OVERHEAD...INCREASING CLOUD COVER SOMEWHAT AND WITH SOME WEAK
WARM AIR ADVECTION BEGINNING ALOFT SOME MODERATION OF TEMPERATURES
IS POSSIBLE.
WEDNESDAY A STRONG CLIPPER IS LIKELY TO MOVE OUT OF CANADA IN THE
LONGWAVE TROUGH. THIS SYSTEM TO STAY MOSTLY NORTH OF THE
AREA...BUT IT WILL PULL SOME WARMER TEMPERATURES ALOFT OVER THE
AREA...FOR A CONTINUATION OF THE WARMING TREND STARTED ON TUESDAY.
HIGHS WEDNESDAY AFTERNOON SHOULD BE IN THE 30S NEARLY EVERYWHERE.
WITH THE CLIPPER NOW HAVING MOVED OFF TO THE EAST BY WEDNESDAY
NIGHT...A FRESH SHOT OF COLDER AIR WILL MOVE INTO THE CWA FROM
THE NORTH AS THE UPPER LEVEL TROUGH AXIS SHARPENS. IT LOOKS LIKE A
SHORTWAVE MAY DIVE THROUGH THE AREA THURSDAY...BUT SOME MODELS
KEEP IT TOO FAR NORTH TO AFFECT THE AREA...SO HAVE LEFT FORECAST
DRY FOR NOW. FRIDAY LOOKS COLD AND DRY AS WELL.
LE
&&
.AVIATION...
CONDITIONS HAVE IMPROVED TO VFR AT KBRL/KMLI AND ARE NOW EXPECTED
TO REMAIN THAT WAY THROUGH 00Z/13. KCID IS EXPECTED TO IMPROVE TO
VFR AROUND 00Z/12. KDBQ WILL REMAIN BELOW MINIMUMS DUE TO
ADVECTION FOG THROUGH 03Z/12. THE RAP MODEL IS NOW SUGGESTING KDBQ
WILL BEGIN IMPROVING AFT 03Z/12 WITH MVFR CONDITIONS DEVELOPING. A
STRONG COLD FRONT WILL MOVE THROUGH EASTERN IOWA AND NORTHERN
ILLINOIS AFT 06Z/12. CONDITIONS ARE EXPECTED TO IMPROVE TO VFR AT
ALL TAF SITES WITH FRONTAL PASSAGE. ..08..
&&
.DVN WATCHES/WARNINGS/ADVISORIES...
IA...DENSE FOG ADVISORY UNTIL 6 PM CST THIS EVENING FOR JACKSON-JONES-
LINN.
DENSE FOG ADVISORY UNTIL MIDNIGHT CST TONIGHT FOR BUCHANAN-
DELAWARE-DUBUQUE.
IL...DENSE FOG ADVISORY UNTIL 6 PM CST THIS EVENING FOR JO DAVIESS-
STEPHENSON.
MO...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS WICHITA KS
1101 AM CST FRI JAN 11 2013
.UPDATE...
THICK CIRRIFORM CLOUDS FOR THE TIME BEING HAVE LIMITED DIURNAL
TEMPERATURE RISE AND LIKEWISE MIXING/INCREASE IN SOUTH WINDS AS
WE APPROACH MIDDAY. THE LATEST RUC AND NAM WOULD SUGGEST WITH
AT LEAST PARTIAL CLEARING THAT STEEPER LAPSE RATES/BEST MIXING
POTENTIAL FOR WIND WILL ARRIVE TOWARD 21Z FOR A FEW HOURS INTO
THE LATE AFTERNOON ACROSS PORTIONS OF CENTRAL KANSAS. THEREFORE
WILL CONTINUE THE CURRENT WIND ADVISORY...THOUGH MORE LIKELY
REALIZING CRITERIA FOR THE LATTER PORTION OF THE HEADLINE PERIOD.
OTHERWISE ONLY SLIGHT ADJUSTMENT TO GRIDS BLENDING LATEST TRENDS
INTO THE AFTERNOON.
KED
&&
.AVIATION...18Z TAFS KRSL/KSLN/KHUT/KICT/KCNU
VFR CONDITIONS EXPECTED TO PREVAIL THRU THE FORECAST VALID PERIOD.
GUSTY SOUTH TO SOUTHWEST WINDS WILL PREVAIL THRU THE AFTERNOON
HOURS AHEAD OF A PACIFIC TROF...WITH ITS PASSAGE EARLY THIS
EVENING FOLLOWED BY STRONGER POLAR COLD FRONT OVERNIGHT. THICK
VEIL OF MAINLY CIRRIFORM CLOUDS SHOULD THIN/SCATTER OUT BY LATER
THIS EVENING/OVERNIGHT.
KED
&&
.PREV DISCUSSION... /ISSUED 553 AM CST FRI JAN 11 2013/
AVIATION...12Z TAFS KRSL/KSLN/KHUT/KICT/KCNU
IFR/MVFR CLOUDS ARE ON THE WANE AS A RESULT OF BOTH AN INCREASE IN
SOUTH WINDS AND THE INFLUX OF RELATIVELY DRIER AIR. HIGH LEVEL
MOISTURE FORECASTS SUGGEST CIRRUS WILL BE PERVASIVE THROUGHOUT THE
DAY...BUT SHOULD WANE SLIGHTLY THIS AFTERNOON. THE COLD FRONT WILL
SWEEP ACROSS ALL SITES AFTER DARK...WITH GUSTY NORTH NORTHWEST
WINDS IN ITS WAKE. MAY SQUEEZE OUT A FEW LOW CLOUDS JUST BEHIND
THE FRONT...BUT NO CEILINGS ARE ANTICIPATED AT THIS TIME.
-HOWERTON
PREV DISCUSSION... /ISSUED 317 AM CST FRI JAN 11 2013/
DISCUSSION...
FORECAST HIGHLIGHTS FOCUS AROUND MILD AND WINDY CONDITIONS
TODAY...COLDER TEMPERATURES SATURDAY-MONDAY...SOUTHEAST KS SNOW
CHANCES SATURDAY EVENING...AND MODERATING TEMPERATURES
TUESDAY-THURSDAY.
WILL GO AHEAD AND NIX THE CURRENT DENSE FOG ADVISORY ACROSS MUCH OF
THE AREA...AS SOMEWHAT WARMER/DRIER AIR IN CONCERT WITH
STRENGTHENING BOUNDARY LAYER WINDS HAS ENCROACHED FROM THE SOUTH.
A POWERFUL SHORTWAVE WILL ROUND THE BASE OF A WESTERN CONUS TROUGH
TODAY...RESULTING IN STRONG CYCLOGENESIS ACROSS THE HIGH PLAINS.
ASSOCIATED STRONG PRESSURE FALLS WILL RESULT IN STOUT/GUSTY
SOUTH/SOUTHWESTERLY WINDS ACROSS THE ENTIRE AREA...LIKELY STRONGEST
WEST OF I-135...WHERE A WIND ADVISORY IS IN EFFECT FROM 11AM-7PM.
CONTEMPLATED EXPANDING INTO EASTERN KS...BUT RELATIVELY MOIST
BOUNDARY LAYER AND SUBSEQUENT LESS DEEP MIXING HEIGHT SHOULD PREVENT
WIDESPREAD WIND ADVISORY CRITERIA THERE. THE DEEP/THICK ATMOSPHERE
AHEAD OF THE WESTERN CONUS LONGWAVE TROUGH IN TANDEM WITH THE STRONG
SOUTHERLY FLOW WILL ALLOW FOR WELL ABOVE NORMAL TEMPERATURES TODAY
ACROSS THE AREA...ALTHOUGH WE SHOULD FALL JUST SHORT OF RECORD HIGHS.
OTHERWISE...A 2ND PIECE OF SHORTWAVE ENERGY ROUNDS THE BASE OF THE
WESTERN CONUS TROUGH SATURDAY EVENING...INTERACTING WITH A STALLED
TIGHT/DEEP FRONTAL ZONE TO POSSIBLY BRING SOME WINTERY PRECIPITATION
TO FAR SOUTHEAST KS. THE LATEST NAM KEEPS THE BEST MID-LEVEL
FRONTOGENESIS TO THE SOUTHEAST OF THE FORECAST AREA...WHICH WOULD
RESULT IN LOWER PRECIPITATION CHANCES. HOWEVER...THE GFS AND
ESPECIALLY THE ECMWF CONTINUES TO KEEP THE BAROCLINIC ZONE A BIT
FURTHER NORTHWEST...WHICH WOULD RESULT IN HIGHER PRECIPITATION
CHANCES OVER FAR SOUTHEAST KS...WITH POTENTIALLY UP TO 1-2 INCHES OF
SNOW IN A NARROW SWATH. FALLING PRECIPITATION WILL HAVE TO OVERCOME
A VERY DRY SUB-700MB LAYER...BUT THINKING STRENGTH OF FRONTOGENESIS
AND NAM/GFS PROGGED MID-LEVEL INSTABILITY IS ENOUGH TO KEEP 40-50
POPS OVER FAR SOUTHEAST KS. IF THE NAM COMES AROUND TO THE GFS/ECMWF
SOLUTIONS...POPS WILL NEED TO BE INCREASED.
OTHERWISE...A MUCH COLDER AIRMASS WILL FILTER SOUTH ACROSS THE
REGION SATURDAY-MONDAY...AS THE WESTERN CONUS LONGWAVE TROUGH TRACKS
EAST...AND REINFORCING SHORTWAVES SHOOT SOUTHEAST OUT OF CANADA.
TEMPERATURES WILL FALL BACK TO BELOW NORMAL VALUES. HOWEVER...MODEL
CONSENSUS SUGGESTS WESTERN CONUS RIDGING BY EARLY-MID WEEK...WHICH
SHOULD RESULT IN MODERATING TEMPERATURES TUESDAY THROUGH WEEKS END.
THE ECMWF CONTINUES TO KICK A SOUTHERN STREAM SYSTEM EAST ACROSS THE
SOUTHERN PLAINS LATE WEEK...BUT IT HAS CONSISTENTLY REMAINED SOUTH
OF THE FORECAST AREA...SO WILL KEEP A DRY FORECAST IN BEYOND
TOMORROW NIGHT.
ADK
FIRE WEATHER...
WINDY AND RELATIVELY WARM CONDITIONS TODAY IN CONCERT WITH FALLING
RELATIVELY HUMIDITY VALUES WILL RESULT IN VERY HIGH GRASSLAND FIRE
DANGER ALL AREAS TODAY...WITH BORDER-LINE EXTREME FIRE DANGER
GENERALLY WEST OF I-135. THERE ARE SOME QUESTIONS ON MAGNITUDE OF
DRIER AIR PUNCHING IN FROM THE WEST THIS AFTERNOON WEST OF
I-135...ALONG WITH THE CURRENT MOIST GROUND FROM RECENT RAINS...SO
HELD OFF ON RED FLAG WARNING. NEVERTHELESS...OUTDOOR BURNING SHOULD
BE AVOIDED TODAY.
ADK
CLIMATE...
DESPITE COOLER AIR FILTERING SOUTHEAST ACROSS THE REGION
TONIGHT...RECORD WARM LOWS MAY BE IN JEOPARDY TODAY.
ADDITIONALLY...WITH FORECAST HIGH TEMPERATURES IN THE MID
60S...THINKING ALL SITES WILL FALL SHORT OF RECORDS WHICH ARE IN THE
UPPER 60S TO LOW 70S.
ADK
&&
.PRELIMINARY POINT TEMPS/POPS...
WICHITA-KICT 65 27 38 19 / 10 10 0 10
HUTCHINSON 64 24 35 16 / 10 0 0 10
NEWTON 64 26 36 17 / 10 10 0 10
ELDORADO 65 29 38 18 / 10 10 10 10
WINFIELD-KWLD 66 32 41 20 / 10 10 10 20
RUSSELL 60 18 29 12 / 10 0 0 10
GREAT BEND 60 20 32 13 / 10 0 0 10
SALINA 61 22 32 16 / 10 0 0 10
MCPHERSON 63 23 34 16 / 10 10 0 10
COFFEYVILLE 66 39 42 22 / 10 10 30 40
CHANUTE 65 36 41 20 / 10 10 20 40
IOLA 64 35 40 20 / 10 10 20 40
PARSONS-KPPF 65 38 42 20 / 10 10 20 40
&&
.ICT WATCHES/WARNINGS/ADVISORIES...
WIND ADVISORY UNTIL 7 PM CST THIS EVENING FOR KSZ032-033-047>051-
067-082-091.
RED FLAG WARNING UNTIL 6 PM CST THIS EVENING FOR KSZ032-047.
&&
$$
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
158 PM EST FRI JAN 11 2013
.UPDATE...
ISSUED AT 155 PM EST FRI JAN 11 2013
UPDATED THE FORECAST EARLIER TO INCLUDE DENSE FOG ADVISORY FOR S
CENTRAL AREAS...AND SPS FOR ALL BUT GOGEBIC AND ONTONAGON COUNTIES
FOR MUCH OF THE REST OF THE TODAY PERIOD. MNM AND ESC REPORTING
STATION HAD BEEN STUCK WITH 1/4SM VIS SINCE APPROX 12Z. SOME
SIGNIFICANT IMPROVEMENT/MIXING HAS BEEN NOTED AROUND AND S OF MNM
OVER THE PAST HOUR. WILL NEED TO CONTINUE TO MONITOR...WITH THE
POTENTIAL OF GETTING RID OF THE ADVISORY AT LEAST TEMPORARILY BY
LATE AFTERNOON.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 545 AM EST FRI JAN 11 2013
WV IMAGERY AND RUC ANALYSIS INDICATED A MID/UPPER LEVEL TROUGH FROM
IDAHO INTO SRN CA AND AZ AND A RIDGE OVER THE ERN CONUS RESULTING IN
SW FLOW FROM THE CENTRAL PLAINS INTO THE NRN GREAT LAKES. ONE
SHORTWAVE TROUGH WAS LIFTING NE FROM CNTRL IL WHILE AN UPSTREAM
SHRTWV WAS MOVING FROM UTAH INTO COLORADO. AT THE SFC...SRLY FLOW
PREVAILED AHEAD OF A BROAD TROUGH EXTENDING FROM NE CO THROUGH CNTRL
SD INTO NW MN. THE BAND OF 295K-300K ISENTROPIC LIFT THAT SUPPORTED
THE BAND OF LIGHT RAIN HAD LIFTED TO THE NORTH AND EAST OF THE CWA
LEAVING A LARGE AREA OF LOW LEVEL MOISTURE AND WEAKER 285K-290K
ISENTROPIC ASCENT(BELOW 850 MB) WHICH SUPPORTED MAINLY PATCHY LIGHT
RAIN OR DRIZZLE. ALTHOUGH 2M TEMPS WERE ABOVE FREEZING ...IN THE 33F
TO 35F AT MOST REPORTING SITES...GROUND TEMPS IN MANY LOCATIONS WERE
STILL AT OR BELOW FREEZING. THE OVERNIGHT RAIN HAS RESULTED IN ICY
SECONDARY ROADS...ESPECIALLY OVER THE HIGHER TERRAIN IN CENTRAL
UPPER MICHIGAN.
TODAY...THE MORE SUBSTANTIAL PCPN ASSOCIATED WITH THE IL SHORTWAVE
WILL PASS WELL TO THE SOUTHEAST OF UPPER MI. HOWEVER...THE MOIST
SRLY FLOW AND CONTINUED WEAK LOW LEVEL ISENTROPIC ASCENT COULD
CONTINUE TO SUPPORT SOME PATCHY LIGHT RAIN AND MAINLY JUST DRIZZLE
BY THIS AFTERNOON. SINCE TEMPS WILL ONLY SLOWLY RISE THIS MORNING
...THE FREEZING RAIN ADVISORY WAS RETAINED THROUGH 12Z.
BY MID TO LATE MORNING...WITH TEMPS INTO THE MID AND UPPER 30S...ANY
LINGERING PROBLEMS WITH ICY ROADS SHOULD DIMINISH.
TONIGHT...MODELS WERE IN GOOD AGREEMENT WITH THE MAIN FEATURES
IMPACTING THE UPPER GREAT LAKES. AS THE CO SHORTWAVE TROUGH LIFTS TO
THE NORTHEAST...A SFC LO IS EXPECTED TO MOVE FROM THE PLAINS TO NE
MN BY 12Z SAT. MODELS INDICATE THAT THE DRY SLOT UNDER THE JET SURGE
WILL DOMINATE...LIMITING PCPN CHANCES TO MAINLY DRIZZLE OR PATCHY
LIGHT RAIN. WITH A STEADY S WIND AND LINGERING LOW CLOUDS...EXPECT
STEADY OR SLOWLY RISING TEMPS THROUGH MUCH OF THE NIGHT AS THE COLD
FRONT ONLY APPROACHES THE FAR WEST BY AROUND 12Z. EXPECT AREAS OF
FOG AWAY FROM THE DOWNSLOPE AREAS NEAR LAKE SUPERIOR WITH MOIST LOW
LEVELS AND MELTING SNOW.
.LONG TERM...(SATURDAY THROUGH THURSDAY)
ISSUED AT 545 AM EST FRI JAN 11 2013
TROF CONTINUES TO AMPLIFY OVER THE WRN CONUS AS PATTERN CHANGE IS
UNDERWAY. TROF WILL SLOWLY PROGRESS E OVER THE NEXT WEEK...THOUGH
WITH UNCERTAIN AMPLITUDE. MEDIUM RANGE GUIDANCE CONTINUES TO SHOW A
STRENGTHENING POLAR VORTEX WITH A GREATLY EXPANDING AND INTENSIFYING
ARCTIC AIR MASS AROUND HUDSON BAY NEXT WEEK. WITH BUILDING HEIGHTS
FORECASTED OVER GREENLAND...THERE SHOULD BE A TENDENCY FOR THE
BITTER COLD AIR TO SLIP INTO THE UPPER LAKES. HOWEVER...WITH PHASE
OF RECENTLY STRENGTHENED MJO FAVORING WARMTH OVER THE ERN CONUS...IT
WILL BE INTERESTING TO SEE HOW FAR S THE REALLY BITTER COLD AIR
SINKS NEXT WEEK IN RESPONSE TO THE DEVELOPING BLOCKING HIGH OVER
GREENLAND. AT LEAST FOR NOW...WOULD STILL BE SKEPTICAL OF ANY MODEL
SOLUTIONS SHOWING 850MB TEMPS NEARING -30C OVER UPPER MI OR SHOWING
ANYTHING MORE THAN A BRIEF INTRUSION OF BITTER COLD AIR GIVEN
COMPETING SIGNALS FOR WARMTH/COLD. SO...FCST WILL CONTINUE TO SHOW A
CONSERVATIVE APPROACH TO THE COLD WITH TEMPS GENERALLY CLOSE TO OR A
LITTLE BLO NORMAL NEXT WEEK. WITH SNOW COVER GETTING THIN IN MANY
AREAS AND NOT LIKELY TO INCREASE MUCH IF AT ALL AWAY FROM THE W AND
WNW WIND LES SNOW BELTS...THERE COULD BE PROBLEMS FOR WATER LINES IF
WE DO SEE ANYTHING MORE THAN JUST A SHORT DURATION OF SEVERE COLD.
AS JUST ALLUDED TO...PATTERN WILL BE A DRY ONE WITH LITTLE CHC FOR
ANY WIDESPREAD SYNOPTIC SNOW...BUT LES WILL BE A PERSISTENT FEATURE
OF THE FCST NEXT WEEK. IT APPEARS WESTERLY WINDS WILL PROBABLY
DOMINATE...PREVENTING MORE WIDESPREAD COVERAGE OF LES IN UPPER MI
MOST DAYS. THE KEWEENAW PENINSULA WILL SEE THE MOST SNOW FROM LES
NEXT WEEK...AND THERE MAY BE FAIRLY SUBSTANTIAL TOTALS FOR THE WEEK
THERE.
BEGINNING SAT...SHORTWAVE/SFC LOW WILL BE IN NE MN AT 12Z. AS SYSTEM
MOVES ENE THRU NRN ONTARIO DURING THE DAY...SHARP COLD FRONT WILL
CROSS UPPER MI. HOWEVER...SINCE STRONGEST DEEP LAYER QVECTOR
CONVERGENCE ACCOMPANYING DISTURBANCE PASSES TO THE N...AXIS OF MID
LEVEL DRY AIR IS FCST TO LINGER AND WILL LIKELY LEAD TO A DRY FROPA.
ONLY EXCEPTION MAY BE OVER THE W...CLOSER TO THE PASSING
DYNAMICS/DEEPER MOISTURE AND WHERE THE LOW-LEVEL FLOW WILL TAKE ON
MORE OF A CYCLONIC UPSLOPE COMPONENT...ESPECIALLY IN THE AFTN. 850MB
TEMPS FALLING TO AROUND -15C TOWARD 00Z SUN WILL ALSO ADD AN
INCREASING LES COMPONENT TO THE MIX. WITH WSW LOW-LEVEL WINDS...BEST
CHC FOR INCREASING -SHSN WILL BE OVER THE KEWEENAW. SHARP CAA (MAX
850MB TEMP FALL IS AROUND 10C IN 6HR) AND ISALLOBARIC WIND ALIGNED
WITH GRADIENT WIND (6MB/3HR PRES RISE FOLLOWING FROPA) WILL LEAD TO
WINDY CONDITIONS AFTER FROPA. SW WIND DIRECTION IS NOT TYPICALLY THE
MOST FAVORABLE DIRECTION FOR HIGH WINDS IN MOST LOCATIONS...BUT WITH
850MB WINDS AROUND 45KT...SOME GUSTS COULD APPROACH WIND ADVY
CRITERIA...MAINLY IN THE 1-3HRS DURING THE ISALLOBARIC WIND PUSH.
MOMENTUM TRANSFER SUGGESTS GUSTS OF 30-40MPH SHOULD GENERALLY BE THE
RULE FOR A FEW HRS AFTER FROPA. IN COMBINATION WITH FALLING SFC
TEMPS W TO E THRU THE DAY...THE AIR WILL BEGIN TO FEEL MUCH
COLDER...ESPECIALLY OVER THE W WHERE TEMP FALL WILL BE MOST
SIGNIFICANT.
SAT NIGHT THRU SUN NIGHT...AS COLDER AIR SETTLES INTO THE UPPER
GREAT LAKES...850MB TEMPS FALL INTO THE -16 TO -19C RANGE. LOOKS
LIKE A POTENTIALLY INTERESTING PERIOD OF LES AS GFS/NAM SHOW
MOISTURE PROFILE DEEPENING TO 10KFT OR MORE. WITH DEEP MOISTURE...
DENDRITIC SNOW GROWTH TEMPS FALLING FIRMLY INTO THE CONVECTIVE
LAYER...AND SFC TROF DRIFTING THRU THE AREA...THERE IS AN INCREASING
SIGNAL FOR MDT/HVY LES. SHOULD BE ABLE TO FLUFF UP SOME RATHER
SIGNIFICANT SNOW ACCUMULATIONS AS SNOW TO WATER RATIOS INCREASE TO
20-30 TO 1. THERE IS SOME UNCERTAINTY IN WIND DIRECTION WHICH WON`T
BE HANDLED WELL UNTIL CLOSER TO THE EVENT. OVERALL...MODELS INDICATE
A W TO WSW WIND SAT EVENING AHEAD OF TROF TO SHIFT WNW/NW SUN
MORNING AS SFC TROF PASSES. WITH SFC TROF APPROACHING...WOULD
EXPECT SAT NIGHT WINDS TO HAVE MORE OF A WSW/SW COMPONENT...
ESPECIALLY CONSIDERING LAND BREEZE COMPONENT WHICH SHOULD BE ACTIVE
AS LOW-LEVEL GRADIENT WINDS DIMINISH. THIS COULD LEAD TO A STRONG
CONVERGENCE ZONE/HVY LES SETTING UP FROM AROUND THE APOSTLE ISLANDS
INTO THE KEWEENAW SAT NIGHT. THE MDT/HVY SNOW WOULD THEN EXPAND TO
INCLUDE WNW/NW FAVORED SNOW BELTS FOR A TIME SUN. AT THIS POINT...
THE KEWEENAW PENINSULA APPEARS MOST LIKELY TO BE IMPACTED LONGEST BY
MDT/HVY LES. CONSIDERED A WATCH FOR KEWEENAW/NRN HOUGHTON COUNTIES
BEGINNING SAT NIGHT...BUT WILL LET NEXT SHIFT TAKE ANOTHER LOOK AS
WINDS MAY END UP MORE BACKED SAT NIGHT THAN CURRENTLY EXPECTED AHEAD
OF SFC TROF OR SFC TROF MAY PASS MORE QUICKLY THAN EXPECTED.
MON-THU...MOSTLY WEST WIND LES WILL CONTINUE. WHERE WINDS ARE
EXPECTED TO BE ONSHORE...OPTED FOR LIKELY/CATEGORICAL POPS DURING
THIS PERIOD. TUE IS ONLY DAY THAT MAY END UP DRY ACROSS UPPER MI AS
WINDS MAY BACK SUFFICIENTLY TO SHIFT LES OFFSHORE. OTHERWISE...
MEDIUM RANGE MODELS CONTINUE TO SHOW SIGNIFICANT
TIMING/TRACK/AMPLITUDE DIFFERENCES ON SHORTWAVES DROPPING SE INTO
THE GREAT LAKES NEXT WEEK TO THE S OF THE INTENSIFYING POLAR VORTEX
AROUND HUDSON BAY. ALSO...RUN-TO-RUN CONTINUITY WITH THE SHORTWAVES
REMAINS VERY POOR. SO...THERE`S NOT A LOT OF CONFIDENCE ON THE
SHORTWAVES AFFECTING THE AREA. IF ONE OF THE WAVES CAN AMPLIFY
SUFFICIENTLY...THEN BITTER COLD AIR WOULD PLUNGE INTO THE AREA.
WHETHER THAT HAPPENS REMAINS TO SEEN.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SATURDAY AFTERNOON)
ISSUED AT 155 PM EST FRI JAN 11 2013
LIFR TO IFR CEILINGS ACCOMPANIED BY VLIFR TO VFR VIS HAVE BEEN
COMMON...STREAMING IN ON VERY MOIST S FLOW. ALTHOUGH THERE HAVE
BEEN POCKETS OF VFR VIS...MOST NOTABLY AT IWD THANKS TO THE
DOWNSLOPE WIND DIRECTION. CMX IS RIGHT ON THE EDGE...AND WILL
CONTINUE TO BOUNCE AROUND...BUT WITH CEILINGS LIKELY KEEPING THE
SITE IN THE IFR TO LOW MVFR RANGE. WINDS WILL BE THE MAIN CHANGE
OVER THE NEXT 24 HOURS...INCREASING AND BECOMING GUSTY WITH GUSTS
NEARING 25KTS AT IWD AND CMX AROUND DAYBREAK.
&&
.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 545 AM EST FRI JAN 11 2013
A TIGHT PRESSURE GRADIENT BETWEEN AN APPROACHING LOW PRESSURE TROUGH
FROM THE NRN PLAINS AND A RIDGE OVER THE EASTERN GREAT LAKES WILL
RESULT IN SOUTH TO SOUTHEAST WINDS TO 25 KNOTS ACROSS THE ERN HALF
OF LAKE SUPERIOR THIS MORNING. WINDS SHOULD STAY AT OR BELOW 20 KTS
OVER THE WEST HALF. WINDS WILL DIMINISH BLO 20 KT FRI AFTERNOON AS
PRES GRADIENT WEAKENS.
WITH A WEAK PRES GRADIENT OVER THE LAKE THIS EVENING...EXPECT SSW WINDS
UNDER 20 KTS WINDS. BUT THE WINDS WILL INCREASE OVERNIGHT AS A DEEP
LOW PRESSURE SYSTEM MOVES NE FROM THE PLAINS INTO NE MN AND TIGHTENS
THE GRADIENT. EXPECT THE WINDS TO INCREASE RAPIDLY ON SAT AS A SHARP
COLD FRONT SLICES ACROSS THE UPPER GREAT LAKES AND THE ARRIVAL OF
MUCH COLDER AIR RESULTS IN DECREASING STABILITY AND GREATER MIXING OF
THE STRONGER WINDS TO THE LAKE SURFACE. A GALE WATCH WAS EXPANDED AS
GALES ARE EXPECTED ACROSS THE LAKE FROM SATURDAY MORNING INTO
SATURDAY EVENING. NOT OUT OF THE QUESTION THAT A FEW STORM FORCE
GUSTS COULD OCCUR OVER THE WRN LAKE AS WELL. THE COMBINATION OF THE
STRONG WINDS...COLDER AIR AND HIGHER WAVES WILL RESULT IN FREEZING
SPRAY AS WELL INTO SAT NIGHT WHEN THE WINDS WILL BE DIMINISHING WITH
THE DEPARTURE OF LOW PRES TO THE NORTHEAST. WINDS IN THE 15 TO 25 KT
RANGE ARE EXPECTED SUNDAY INTO MONDAY...BUT THE APPROACH OF ANOTHER
DISTURBANCE LATER ON TUE TUE AND NIGHT MIGHT RESULT IN W-SW WINDS
INCREASING TO GALES.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
DENSE FOG ADVISORY UNTIL 7 PM EST /6 PM CST/ THIS EVENING FOR
MIZ011>013.
LAKE SUPERIOR...
GALE WARNING FROM 10 AM EST /9 AM CST/ TO 10 PM EST /9 PM CST/
SATURDAY FOR LSZ240>246-265>267.
GALE WARNING FROM 7 AM EST /6 AM CST/ TO 10 PM EST /9 PM CST/
SATURDAY FOR LSZ162-263-264.
LAKE MICHIGAN...
DENSE FOG ADVISORY UNTIL 7 AM EST SATURDAY FOR LMZ221-248-250.
GALE WARNING FROM 11 AM TO 9 PM EST SATURDAY FOR LMZ221-248-250.
&&
$$
UPDATE...KF
SHORT TERM...JLB
LONG TERM...ROLFSON
AVIATION...KF
MARINE...JLB
AREA FORECAST DISCUSSION
NWS HASTINGS NE
405 PM CST FRI JAN 11 2013
.SHORT TERM...NOW THROUGH SATURDAY
...WINTERS COLD RETURNS TO THE CNTRL PLAINS TONIGHT WITH A PERIOD OF
STRONG WIND GUSTS IN THE TRANSITION...
AN SPS WAS ISSUED AT 2032Z FOR THE BLOWING DUST AND WILL PROBABLY
BE UPDATED BY THE BOTTOM OF THE HOUR.
WIND ADVISORIES CONTINUE AS POSTED. NPW WAS UPDATED/SENT AT 324 PM
TO RAISE ADDITIONAL AWARENESS OF BLOWING DUST OVER KS.
NOW: STRONG COLD FRONT IS SAGGING SE THRU CNTRL NEB. IT WAS LAST
SEEN ON THE LNX 88D AT 1825Z JUST NW OF BBW. THE TIMING TOOL BRINGS
IT INTO GRI BY 2230Z. 992 MB LOW WAS TRACKING ALONG THE KS-NEB
BORDER...S OF WHERE IT WAS FCST 24 HRS AGO.
THE FRONT IS AHEAD OF SCHEDULE SO USED THE RAP FOR SHORT-TERM WINDS.
THE 18Z RAP SUGGESTS IT FINALLY CUTS NE THIS EVNG ACROSS ERN NEB.
BLOWING DUST: A BURST OF 33-41 KT WINDS HAS RESULTED IN A LARGE AREA
OF BLOWING DUST THAT ORIGINATED OVER ERN CO. TIMING TOOL WILL BRING
THIS INTO OUR KS COUNTIES AROUND 445 PM AND IT WILL CONTINUE UNTIL
WIND SHIFT ASSOCIATED WITH COLD FRONTAL PASSAGE.
CONTEMPLATED CANCELLING THE WIND ADVISORY FOR N-CNTRL KS SINCE WINDS
HAVE BEEN WELL BELOW ADVISORY SUSTAINED OR GUSTS. BUT GIVEN MULTIPLE
G40 KTS WITH THAT DUST...HAVE CONTINUED ADVISORY.
A LARGE AREA OF STRATUS IS EXPECTED TO SINK S BEHIND THE FRONT TNGT
IN THE WAKE OF THE DEPARTING LOW. HOW FAR S OVC EXTENDS REMAINS
UNCERTAIN GIVEN DOWNSLOPING WINDS WILL TEND TO BREAK IT UP.
WIND: 3 HR PRES RISES ARE ONLY 3 MB OVER THE NEB PANHANDLE AT 21Z.
THE NAM IS OVER ESTIMATING THIS BY 5 MB AND THE RAP BY 3 MB. THINK
THE TREND IS RIGHT WITH EXPANDING/INCREASING PRES RISES AS THE LOW
ACCELERATES NEWD THIS EVE...BUT THE MAGNITUDE MAY BE OVERDONE.
CONFIDENCE IS ABOVE AVERAGE FOR VERIFYING THE ADVISORY OVER N-CNTRL
KS AHEAD OF THE FRONT. IT/S TAKEN ALL DAY BUT IT WILL VERIFY
22Z-03Z. BEHIND THE FRONT HAVE YET TO SEE ADVISORY LEVEL WINDS
DEVELOP. LOW-LEVELS WILL BECOME UNSTABLE IN CAA THIS EVE AND BUT
THIS APPEARS A MARGINAL WIND EVENT SO VERIFYING NEB WIND ADVISORY IS
BELOW AVERAGE ALONG AND S OF I-80. BEST CHANCE FOR A ONE-TIME 45 MPH
GUST WILL BE N OF THE TRI-CITIES. THE BEST CHANCE FOR VERIFYING
ALONG AND S OF I-80 WILL PROBABLY BE A BRIEF PERIOD OF SUSTAINED
WINDS OF 30 MPH.
TNGT: M/CLOUDY WITH BLUSTERY NW WINDS. SOME FLURRIES OR BRIEF SHSN
WILL OCCUR 6PM-12AM IN PULSE OF CAA. TEMP GUIDANCE WAS IN GOOD
AGREEMENT AND USED THE CONSENSUS OF ALL GUIDANCE WHICH BASICALLY
PUTS TEMPS NEAR NORMAL.
SAT: A MIX OF CLOUDS/SUN. UNSURE HOW MUCH STRATOCU GETS TRAPPED
UNDER FRONTAL INVERSION. HAVE ALREADY INCREASED CLOUDS ABOVE
PREVIOUS GID FCST AND IF NAM BUFKIT IS RIGHT THAN WE WILL BE TOO
LOW ON CLOUD COVER. REGARDLESS...PATCHES JET STREAM CIRRUS WILL
KEEP THE SKY AT LEAST P/CLOUDY. STILL A BLUSTERY NW WIND WITH GUST
UP TO 30 MPH FORENOON. TEMPS ARE NAM 2M TEMPS WHICH IS CLOSE TO
THE PREVIOUS FCST...ABOUT 12F BELOW NORMAL.
.LONG TERM...SATURDAY NIGHT THROUGH FRIDAY. THIS WILL LIKELY BE A
DRY PERIOD WITH TEMPERATURES GENERALLY WARMING THROUGH AT LEAST
WEDNESDAY. MORE UNCERTAINTY ENTERS THE PICTURE BY THURSDAY AND
FRIDAY.
SATURDAY NIGHT THROUGH MONDAY...A COLD AREA OF ARCTIC HIGH PRESSURE
WILL BEGIN TO SLIDE INTO THE PLAINS SATURDAY NIGHT INTO SUNDAY AND
REMAIN THROUGH AT LEAST MONDAY. THERE WILL BE A LARGE UPPER TROUGH
SITUATED OVER THE PLAINS BUT ALL OF THE MOISTURE WILL BE AT THE
LEADING EDGE OF THIS TROUGH AND WELL OFF TO OUR EAST. HIGH
TEMPERATURES WILL BE STUCK IN THE 20S ON SUNDAY AND POSSIBLY MONDAY
AS WELL. SOME AREAS THAT ARE COMPLETELY FREE OF SNOW COVER MAY REACH
THE LOWER 30S ON MONDAY.
TUESDAY AND WEDNESDAY...THE 12Z ECMWF PUSHES THE SFC HIGH OFF TO OUR
SOUTH ALLOWING FOR WEST SOUTHWEST DOWNSLOPE SFC WINDS. THE SHALLOW
COLD AIR WILL GRADUALLY MODERATE WITH HIGH TEMPERATURES BACK INTO
THE 30S ON TUESDAY AND PROBABLY 40S BY WEDNESDAY.
THURSDAY THROUGH FRIDAY...THERE IS A SUBSTANTIAL AMOUNT OF MODEL
UNCERTAINTY WITH REGARD TO TEMPERATURES. HOWEVER...THERE IS GOOD
MODEL AGREEMENT IN DRY CONDITIONS. THE ECMWF BRINGS A COLD FRONT
THROUGH WEDNESDAY NIGHT WITH STRONG COLD AIR ADVECTION ON THURSDAY.
THE 850 MB TEMPERATURES THURSDAY EVENING RANGE FROM -15C ON THE 12Z
ECMWF TO 5C ON THE 12Z GFS FOR A SIGNIFICANT 20C DEGREE SPREAD. THE
OFFICIAL FORECAST IS SOMEWHERE IN THE MIDDLE OF THESE TWO MODELS
CALLING FOR ABOVE FREEZING HIGHS IN THE UPPER 30S TO LOWER 40S.
HOWEVER...THESE HIGHS MAY VERY WELL BE TOO WARM. THE ONGOING
STRATOSPHERIC WARMING EVENT WILL LIKELY RESULT IN THE TRANSITION TO
A NEGATIVE ARCTIC OSCILLATION PATTERN...WHICH TENDS TO BRING THE
COLD AIR DOWN OUT OF CANADA INTO THE EASTERN TWO THIRDS OF THE
CONUS. THEREFORE...I WOULD LEAN MORE TOWARDS THE ECWMF AND THE
POSSIBILITY OF COLDER TEMPERATURES THAN WHAT WE ARE OFFICIALLY
CALLING FOR AS THIS BETTER FITS THE -AO PATTERN. IF THE 12Z ECMWF
COLDER TREND CONTINUES...WE WILL NEED TO BE LOWERING OUR THURSDAY
AND FRIDAY HIGH TEMPERATURES.
&&
.PREV DISCUSSION... /ISSUED 1230 PM CST FRI JAN 11 2013/
AVIATION...(18Z GRI TAF THROUGH 18Z SATURDAY AFTERNOON)
THIS AFTN: VLIFR VSBY HAS IMPROVED AND CONTINUED IMPROVEMENT IS
EXPECTED. HOWEVER...LIFR/IFR STRATUS CIGS MAY CONTINUE FOR THE
REST OF THE DAY. CURRENTLY THE TAF IS OPTIMISTIC WITH VFR
CIGS/VSBYS BY 1930Z. STRATUS IS DECREASING FROM THE S /HSI IS VFR/
BUT INCREASING FROM THE N. EXPECT LIGHT S WINDS TO CONTINUE.
TNGT: MVFR CIGS. A COLD FRONT IS JUST N OF THE TERMINAL. THIS
FRONT WILL MOVE THRU AROUND 01Z WITH A WIND SHIFT. COULD SEE A
BRIEF BURST OF MVFR FLURRIES BUT CONFIDENCE IS NOT HIGH ENOUGH TO
INCLUDE IN TAF. WNW WINDS WILL GUST TO 35-40 KTS BETWEEN 01-08Z
WITH A ONE-TIME PEAK GUST OF 45 KTS POSSIBLE. HAVE INDICATED MVFR
CIGS BUT COULD BEGIN AS IFR CIGS WITH GRADUAL IMPROVEMENT TO MVFR.
STRONGEST WINDS SUBSIDE BY 08Z.
SAT THRU 18Z: MVFR CIGS. VSBYS UNRESTRICTED. NW WINDS 15-25 KTS.
CIG CONFIDENCE: BELOW AVERAGE THRU 03Z THEN AVERAGE
VSBY CONFIDENCE: AVERAGE THRU 21Z THEN HIGH
WIND CONFIDENCE: AVERAGE
WX CONFIDENCE: HIGH
&&
.GID WATCHES/WARNINGS/ADVISORIES...
NE...WIND ADVISORY FROM 8 PM THIS EVENING TO 1 AM CST SATURDAY FOR
NEZ039>041-046>049-060>064-074>077.
KS...WIND ADVISORY UNTIL 10 PM CST THIS EVENING FOR KSZ005-006-
017>019.
&&
$$
SHORT TERM...HALBLAUB
LONG TERM...WESELY
AVIATION...HALBLAUB
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
404 PM EST FRI JAN 11 2013
.SYNOPSIS...
AN UPPER LEVEL RIDGE WILL REMAIN OVER THE EASTERN PART OF THE
COUNTRY INTO THE WEEKEND. A SERIES OF WEAKENING DISTURBANCES WILL
MOVE THROUGH THIS UPPER RIDGE...BRINGING OCCASIONAL BOUTS OF
MAINLY LIGHT PRECIPITATION ALONG WITH UNSEASONABLE WARMTH. THE
WEATHER WILL REMAIN UNSETTLED THROUGH MIDWEEK...WHEN MUCH COLDER
AIR WILL MOVE IN FROM THE GREAT LAKES.
&&
.NEAR TERM /UNTIL 11 PM THIS EVENING/...
SHORT WAVE TROUGH EVIDENT ON WV IMAGERY OVER LAKE ERIE/NERN OH
AND RIGHT ON TIME. MAIN SLUG OF PRECIP SEEMS TO BE UPON THE REGION
AT 19Z...WITH GENERALLY LIGHT AND SPOTTY SHRA BEHIND THAT. THE
BACK EDGE OF THE PRECIP IS RIGHT ALONG WITH THE BASE OF THE
TROUGH AND EXTRAPOLATION MOVES MOST OF THE PRECIP TO THE EAST OF
THE ENTIRE AREA BY 00Z. TEMPS SHOULD HOLD RELATIVELY STEADY INTO
THE EVENING AS THE RAIN AND CLOUDS DOMINATE. THEY COULD WARM UP
5-6F IN THE WEST DURING THE EVENING AS WINDS TURN MORE SWRLY.
&&
.SHORT TERM /11 PM THIS EVENING THROUGH 6 PM SATURDAY/...
WAVE TO THE EAST BEFORE THE PERIOD STARTS...SO ONLY THE LOW CLOUDS
WILL BE LEFT OVER. THESE CLOUDS ARE THE FORECAST PROBLEM FOR THE
PERIOD. CLOUDS A DRIZZLE OVER MOST OF THE AREA OVERNIGHT WILL KEEP
IT VERY MILD...WITH OVERNIGHT MINS 15-25F ABOVE NORMALS...AND EVEN
5-10F ABOVE NORMAL MAXES. IF IT WAS NOT FOR THE LOW CLOUDS WE
WOULD EASILY REACH RECORD MAXES SAT. BUT THE TREND IN THE MODEL
PROGS THESE LAST 36+ HRS IS TO LINGER THE CLOUDS WELL INTO THE
DAY IN THE CENTRAL AND EASTERN ZONES. SFC HIGH WILL BE RIGHT OVER
THE LOCAL AREA LEADING TO LIGHT WINDS. SO SOME LOCATIONS IN THE
EAST MAY NEVER GET OUT OF THE SOUP. HAVE THEREFORE KEPT MAXES IN
THE M40S AROUND IPT AND IN THE L-M50S FOR A GREAT PORTION OF THE
AREA. U50S STILL POSSIBLE IN THE SOUTH. WHILE IT MAY SEEM LIKE
IPT/VCTY WILL BE MISSING OUT ON WARMTH...IT SHOULD STILL BE 15F
ABOVE NORMAL MAXES - WHICH IS ABNORMALLY WARM FOR ANY POINT IN THE
YEAR. IT IS JUST JANUARY - AND THE NEXT TWO WEEKS ARE THE COLDEST
PERIOD OF THE YEAR CLIMATOLOGICALLY SPEAKING. OTHER THAN A LITTLE
DRIZZLE OUT OF THE LOWEST CLOUDS ON SAT AM...NO OTHER PRECIP IS
FORESEEN. SFC RIDGE AXIS DOES MOVE SLIGHTLY TO THE EAST OF THE
AREA BY SAT EVENING.
&&
.LONG TERM /SATURDAY NIGHT THROUGH FRIDAY/...
MILD WEATHER FOR THE WEEKEND AND EARLY NEXT WEEK WILL GIVE WAY TO
COOL DOWN FOR LATE WEEK.
AN UPPER RIDGE OVER THE REGION SAT WILL SLOWLY SLIDE EAST BY
SUNDAY...ALLOWING A WEAK WARM FRONT TO SLIP THROUGH SAT NIGHT -
ACCOMPANIED BY A CHANCE FOR SHOWERS. BETTER RAIN CHANCES WILL
REMAIN OFF TO OUR WEST ALONG A COLD FRONT SLOWLY INCHING EASTWARD
TOWARD THE REGION. THIS WILL ALLOW VERY MILD AIR TO REMAIN IN
PLACE THROUGH THE WEEKEND...WITH HIGHS IN MOST PLACES REACHING THE
50S...AND POSS 60F ACOSS SOUTHERN TIER.
MODELS ALL HAVE PRETTY GOOD TIMING AGREEMENT ON THE THIS INITIAL
FRONTAL BOUNDARY AND SOME WEAK SHORTWAVES RIDING ALONG IT. HIGHEST
POPS INTO SUNDAY REMAIN IN WESTERN AREAS NEAREST THE
BOUNDARY...WHERE IT SHOULD REMAIN INTERMITTANTLY SHOWERY. FRONT
PUSHES THROUGH SUN NIGHT INTO MON...WITH MORE WIDESPREAD
PRECIPITATION. QPF TOTALS THROUGH THAT 36-48H PERIOD LOOK TO BE
AROUND 1.0-1.5 INCHES IN NW MTNS...TAPERING TO AROUND 0.5 IN THE
SE. WITH A SNOWPACK /WATER EQUIV AROUND AN INCH/ PERSISTING IN THE
NORTHERN MOUNTAINS...THERE WILL BE AT LEAST A SMALL POTENTIAL FOR
SCT MINOR FLOODING ISSUES. BUT LOOKS LIKE PRECIP WILL BE SPREAD
OUT ENOUGH IN TIME AND NOT HEAVY ENOUGH TO CAUSE WIDESPREAD
ISSUES...THOUGH RIVERS AND STREAMS ACROSS CENTRAL PA WILL SEE
NOTICABLE RISES THIS WEEKEND.
AS FRONTAL BOUNDARY SLOWS FURTHER JUST TO OUR SOUTHEAST MON INTO
TUE...OPERATIONAL MODELS SUGGEST THE POTENTIAL FOR AT LEAST ONE
ADDITIONAL WAVE TO RIPPLE UP THAT FRONT. WITH THE COLD AIR
BEGINNING TO OOZE IN FROM THE NW BRINGING 850MB TEMPS BACK BELOW
0C...THE NORTHERN EDGE OF THE PRECIP RUNS THE RISK OF BEING
SNOW...AS WOULD BE EXPECTED IN MOST NORMAL JANUARYS. AMOUNTS
SHOULD BE LIGHT...BUT CONTINUED THE RAIN/SNOW MIX IN WX GRIDS WITH
DIMINISHING POPS.
MODEL DIFFERENCES ARISE BY MIDWEEK CONCERNING ARRIVAL OF COLDER
AIR...BUT TREND WILL MOST DEFINITELY BE COLDER. GFS BRINGS A
POTENT SURGE OF ARCTIC AIR OUR WAY FOR LATER WED INTO THU...WHILE
THE ECMWF/ECENS ARE SLOWER...AND CLOSER TO THE END OF THE WEEK.
THE GFS/GEFS ALSO SHOW A MORE SIGNIFICANT EVENTUAL SOUTHWARD
PLUNGE OF THE COLD AIR INTO THE EASTERN US WHILE THE ECMWF/ECENS
SUGGEST MORE OF A GLANCING BLOW WITH THE BEST COLD CONFINED TO THE
NERN US...ESPECIALLY NEW ENGLAND/NY.
BROAD NW FLOW BRINGS SCT SNOW SHOWERS BACK TO NW MTNS LATE WEEK AS
TEMPS COOL BACK TOWARD NORMALS.
&&
.AVIATION /21Z FRIDAY THROUGH WEDNESDAY/...
WINDOW OF STRONGER WINDS IS SHRINKING AND ONLY A BRIEF PERIOD
EXISTS FOR GOOD MIXING OVER THE AREA. WILL THEREFORE KEEP WIND
SPEEDS LOWER THAN 10 KTS FOR MOST TERMINALS...AND LEAVE THEM ONLY
SLIGHTLY GUSTY IN THE WEST FOR 2-3 MORE HRS. LLWS STILL A CONCERN
INTO THE EARLY EVENING - UNTIL THE SHORT WAVE IS PAST US.
MULTIPLE BANDS OF SHOWERS HAVE CONGEALED INTO ONE MAJOR BAND/AREA
AND A WIDE AREA OF SCT/NMRS SHRA TO THE WEST. THE RETURNS ARE
MOVING STEADILY AND TIMING SUPPORTED BY LATEST HRRR SHUNTS MOST
OF THE RAIN TO THE EAST OF THE AREA BY 02Z. ALMOST NO RISK FOR
THUNDER NOW...SO NO MENTION PLACED INTO THE TAFS. RESIDUAL LOW LVL
MOISTURE AND A NEARLY CALM WIND AND A BIT OF COOLING WILL LIKELY
LEAD TO WIDESPREAD LOW CLOUDS/FOG OVERNIGHT. LATEST SREF/NAM AND GFS
FCSTS ALL SUPPORT THIS SCENARIO...INDICATING WIDESPREAD IFR CONDS
LIKELY. GFS MOS IS MUCH MORE OPTIMISTIC...BUT PREPONDERANCE OF
EVIDENCE POINTS TO LOW CLOUDS AND EVEN DRIZZLE PERSISTING INTO SAT
MORNING. THICK LOW CLOUDS LINGER FOR THE MORNING HOURS ON
SAT...AND MOST IF NOT ALL OF THE DAY IN THE EAST. A SFC LOW PASSES
WELL TO THE NORTH ON SUNDAY AND THE COLD FRONT ASSOCD WITH IT GOES
THRU VERY SLOWLY. AT LEAST ONE MORE WAVE OF LOW PRESSURE RIDES UP
FROM THE S ON MONDAY...GIVING LITTLE BREAK FROM A MONOTONOUS
MVFR/IFR FORECAST IN RAIN AND LOW CLOUDS/FOG.
OUTLOOK...
SUN...VFR SE...MVFR/IFR IN SHRA/CIGS NW.
MON...MVFR IN WIDESPREAD SH/RA.
MON NITE...CFROPA...NW/UPSLOPE FLOW SHSN.
TUE-WED...MAINLY VFR.
&&
.CTP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...DANGELO/LA CORTE
NEAR TERM...DANGELO
SHORT TERM...DANGELO
LONG TERM...RXR
AVIATION...DANGELO
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
240 PM EST FRI JAN 11 2013
.SYNOPSIS...
AN UPPER LEVEL RIDGE WILL REMAIN OVER THE EASTERN PART OF THE
COUNTRY INTO THE WEEKEND. A SERIES OF WEAKENING DISTURBANCES WILL
MOVE THROUGH THIS UPPER RIDGE...BRINGING OCCASIONAL BOUTS OF
MAINLY LIGHT PRECIPITATION ALONG WITH UNSEASONABLE WARMTH. THE
WEATHER WILL REMAIN UNSETTLED THROUGH MIDWEEK...WHEN MUCH COLDER
AIR WILL MOVE IN FROM THE GREAT LAKES.
&&
.NEAR TERM /UNTIL 11 PM THIS EVENING/...
SHORT WAVE TROUGH EVIDENT ON WV IMAGERY OVER LAKE ERIE/NERN OH
AND RIGHT ON TIME. MAIN SLUG OF PRECIP SEEMS TO BE UPON THE REGION
AT 19Z...WITH GENERALLY LIGHT AND SPOTTY SHRA BEHIND THAT. THE
BACK EDGE OF THE PRECIP IS RIGHT ALONG WITH THE BASE OF THE
TROUGH AND EXTRAPOLATION MOVES MOST OF THE PRECIP TO THE EAST OF
THE ENTIRE AREA BY 00Z. TEMPS SHOULD HOLD RELATIVELY STEADY INTO
THE EVENING AS THE RAIN AND CLOUDS DOMINATE. THEY COULD WARM UP
5-6F IN THE WEST DURING THE EVENING AS WINDS TURN MORE SWRLY.
&&
.SHORT TERM /11 PM THIS EVENING THROUGH 6 PM SATURDAY/...
WAVE TO THE EAST BEFORE THE PERIOD STARTS...SO ONLY THE LOW CLOUDS
WILL BE LEFT OVER. THESE CLOUDS ARE THE FORECAST PROBLEM FOR THE
PERIOD. CLOUDS A DRIZZLE OVER MOST OF THE AREA OVERNIGHT WILL KEEP
IT VERY MILD...WITH OVERNIGHT MINS 15-25F ABOVE NORMALS...AND EVEN
5-10F ABOVE NORMAL MAXES. IF IT WAS NOT FOR THE LOW CLOUDS WE
WOULD EASILY REACH RECORD MAXES SAT. BUT THE TREND IN THE MODEL
PROGS THESE LAST 36+ HRS IS TO LINGER THE CLOUDS WELL INTO THE
DAY IN THE CENTRAL AND EASTERN ZONES. SFC HIGH WILL BE RIGHT OVER
THE LOCAL AREA LEADING TO LIGHT WINDS. SO SOME LOCATIONS IN THE
EAST MAY NEVER GET OUT OF THE SOUP. HAVE THEREFORE KEPT MAXES IN
THE M40S AROUND IPT AND IN THE L-M50S FOR A GREAT PORTION OF THE
AREA. U50S STILL POSSIBLE IN THE SOUTH. WHILE IT MAY SEEM LIKE
IPT/VCTY WILL BE MISSING OUT ON WARMTH...IT SHOULD STILL BE 15F
ABOVE NORMAL MAXES - WHICH IS ABNORMALLY WARM FOR ANY POINT IN THE
YEAR. IT IS JUST JANUARY - AND THE NEXT TWO WEEKS ARE THE COLDEST
PERIOD OF THE YEAR CLIMATOLOGICALLY SPEAKING. OTHER THAN A LITTLE
DRIZZLE OUT OF THE LOWEST CLOUDS ON SAT AM...NO OTHER PRECIP IS
FORESEEN. SFC RIDGE AXIS DOES MOVE SLIGHTLY TO THE EAST OF THE
AREA BY SAT EVENING.
&&
.LONG TERM /SATURDAY NIGHT THROUGH FRIDAY/...
WE ARE IN FOR A MILD START TO THE EXTENDED PART OF THE FORECAST.
THE UPPER RIDGE MAINTAINS ITSELF INTO THE WEEKEND...WHICH RESULTS
IN THE APPROACHING COLD FRONT SLOWING DOWN AND BECOMING WAVY AS
IT INCHES EAST. THIS KEEPS US IN THE MILD AIR THROUGH AT LEAST
SUNDAY BEFORE THE COLD FRONT FINALLY REINTRODUCES THE COLD AIR
STARTING ON MONDAY.
MODELS ALL HAVE PRETTY GOOD TIMING AGREEMENT ON THE THIS INITIAL
FRONTAL BOUNDARY...BUT AS USUAL...DIFFERENCES ARISE AS WE GO OUT
IN TIME. THE GFS BRINGS A POTENT SURGE OF ARCTIC AIR OUR WAY FOR
LATER WED INTO THU...WHILE THE ECMWF/ECENS ARE SLOWER...AND CLOSER
TO THE END OF THE WEEK. THE GFS/GEFS ALSO SHOW A MORE SIGNIFICANT
EVENTUAL SOUTHWARD PLUNGE OF THE COLD AIR INTO THE EASTERN US
WHILE THE ECMWF/ECENS SUGGEST MORE OF A GLANCING BLOW WITH THE
BEST COLD CONFINED TO THE NERN US...ESPECIALLY NEW ENGLAND/NY.
SENSIBLE WEATHER WILL BE GOVERNED BY THE FRONT THAT WILL ONLY
SLOWLY MOVE OFF TO OUR SE AS IT STRUGGLES AGAINST THE BROAD SW
FLOW ALOFT IN THE STRONG UPPER RIDGE THAT WILL BE STUBBORN TO
RETREAT OFF THE SERN US. OPERATIONAL MODELS SUGGEST THE POTENTIAL
FOR AT LEAST ONE ADDITIONAL WAVE TO RIPPLE UP THAT FRONT FOR SOME
TIME LATER MONDAY INTO TUESDAY. WITH THE COLD AIR GETTING
CLOSER...THE NORTHERN EDGE OF THE PRECIP RUNS THE RISK OF BEING
SNOW...AS WOULD BE EXPECTED IN MOST NORMAL JANUARYS. IT IS TOO
FAR OUT TO GET FANCY SO THE FORECAST HAS RAIN OR SNOW AT THIS
RANGE...AND HOLDS OFF THE COLDEST AIR UNTIL LATE WEEK.
&&
.AVIATION /19Z FRIDAY THROUGH WEDNESDAY/...
WINDOW OF STRONGER WINDS IS SHRINKING AND ONLY A BRIEF PERIOD
EXISTS FOR GOOD MIXING OVER THE AREA. WILL THEREFORE KEEP WIND
SPEEDS LOWER THAN 10 KTS FOR MOST TERMINALS...AND LEAVE THEM ONLY
SLIGHTLY GUSTY IN THE WEST FOR 2-3 MORE HRS. LLWS STILL A CONCERN
INTO THE EARLY EVENING - UNTIL THE SHORT WAVE IS PAST US.
MULTIPLE BANDS OF SHOWERS HAVE CONGEALED INTO ONE MAJOR BAND/AREA
AND A WIDE AREA OF SCT/NMRS SHRA TO THE WEST. THE RETURNS ARE
MOVING STEADILY AND TIMING SUPPORTED BY LATEST HRRR SHUNTS MOST
OF THE RAIN TO THE EAST OF THE AREA BY 02Z. ALMOST NO RISK FOR
THUNDER NOW...SO NO MENTION PLACED INTO THE TAFS. RESIDUAL LOW LVL
MOISTURE AND A NEARLY CALM WIND AND A BIT OF COOLING WILL LIKELY
LEAD TO WIDESPREAD LOW CLOUDS/FOG OVERNIGHT. LATEST SREF/NAM AND GFS
FCSTS ALL SUPPORT THIS SCENARIO...INDICATING WIDESPREAD IFR CONDS
LIKELY. GFS MOS IS MUCH MORE OPTIMISTIC...BUT PREPONDERANCE OF
EVIDENCE POINTS TO LOW CLOUDS AND EVEN DRIZZLE PERSISTING INTO SAT
MORNING. THICK LOW CLOUDS LINGER FOR THE MORNING HOURS ON
SAT...AND MOST IF NOT ALL OF THE DAY IN THE EAST. A SFC LOW PASSES
WELL TO THE NORTH ON SUNDAY AND THE COLD FRONT ASSOCD WITH IT GOES
THRU VERY SLOWLY. AT LEAST ONE MORE WAVE OF LOW PRESSURE RIDES UP
FROM THE S ON MONDAY...GIVING LITTLE BREAK FROM A MONOTONOUS
MVFR/IFR FORECAST IN RAIN AND LOW CLOUDS/FOG.
OUTLOOK...
SUN...VFR SE...MVFR/IFR IN SHRA/CIGS NW.
MON...MVFR IN WIDESPREAD SH/RA.
MON NITE...CFROPA...NW/UPSLOPE FLOW SHSN.
TUE-WED...MAINLY VFR.
&&
.CTP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...DANGELO/LA CORTE
NEAR TERM...DANGELO
SHORT TERM...DANGELO
LONG TERM...LA CORTE
AVIATION...DANGELO
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
102 PM EST FRI JAN 11 2013
.SYNOPSIS...
AN UPPER LEVEL RIDGE WILL REMAIN OVER THE EASTERN PART OF THE
COUNTRY INTO THE WEEKEND. A SERIES OF WEAKENING DISTURBANCES WILL
MOVE THROUGH THIS UPPER RIDGE...BRINGING OCCASIONAL BOUTS OF
MAINLY LIGHT PRECIPITATION ALONG WITH UNSEASONABLE WARMTH. THE
WEATHER WILL REMAIN UNSETTLED THROUGH MIDWEEK...WHEN MUCH COLDER
AIR WILL MOVE IN FROM THE GREAT LAKES.
&&
.NEAR TERM /UNTIL 11 PM THIS EVENING/...
FCST WELL ON TRACK WITH THE MAJOR SHORT WAVE TROUGH SLATED TO PUSH
THROUGH PA BY 03Z. THE MAIN FORCING WILL BE ABOUT 3-4 HRS
AHEAD...AND HIGH POPS ALL AROUND. MAIN SLUG OF PRECIP SEEMS TO BE
UPON THE WRN HALF OF THE AREA...WITH GENERALLY LIGHT AND SPOTTY
SHRA BEHIND THAT. THE BACK EDGE OF THE PRECIP AND MOST LIKELY THE
BASE OF THE TROUGH IS ALREADY INTO EASTERN OHIO. SOME LIMITED
ELEVATED INSTABILITY IS POSSIBLE OVER THE WESTERN/CENTRAL MTS
LATE THIS AFTN/EARLY EVENING...WITH JUST A MENTION NEEDED AND IN
THERE ALREADY. TEMPS SHOULD HOLD RELATIVELY STEADY INTO THE
EVENING AS THE RAIN AND CLOUDS DOMINATE.
&&
.SHORT TERM /11 PM THIS EVENING THROUGH 6 PM SATURDAY/...
THE UPPER SHORTWAVE WILL SCOOT QUICKLY THROUGH THE RIDGE...WITH
RISING HEIGHTS ALOFT RETURNING BY EVENING. KEPT THE BEST CHANCE
FOR LINGERING SHOWERS EARLY IN THE PERIOD IN THE EAST...WITH
DRYING SETTING IN OVERNIGHT. I DID NOT GO FOR A LOT OF FOG WHICH
WOULD NORMALLY SEEM TO BE THE WAY TO GO WITH RAIN ENDING AND HIGH
PRESSURE QUICKLY BUILDING IN OVERNIGHT...BUT AT THIS POINT I
EXPECT A LOT OF RESIDUAL CLOUDINESS SHUD THWART SIG RADIATIONAL
COOLING AND FOG FORMATION. WILL HAVE HIGH CLOUDS PAINTED THRU THE
PERIOD...WHICH WILL LIMIT THE TEMP RISE EARLY ON SAT. IF IT WAS
NOT FOR THE LOW CLOUDS WE WOULD EASILY REACH RECORD MAXES SAT.
BUT THE CLOUDS NOW LOOK TO LINGER WELL INTO THE DAY IN THE CENTRAL
AND EASTERN ZONES. HAVE THEREFORE KEPT MAXES IN THE U40S AT IPT
AND L50S FOR A GREAT PORTION OF THE AREA. U50S STILL
POSSIBLE...BUT THAT MAY BE A BIT AMBITIOUS WITH CURRENT CLOUD
OUTLOOK.
WITH THE APPROACHING FRONT PRETTY MUCH WASHING AS IT MOVES OUR
WAY...WE WILL REMAIN ESSENTIALLY IN THE WARM SECTOR OF THE
STRONGER LOW STILL WAY OUT TO OUR WEST...THUS A MILD NIGHT IS IN
STORE WITH READINGS PROBABLY STAYING ABOVE FREEZING
EVERYWHERE...QUITE UNUSUAL FOR MID JANUARY...THE CLIMATALOGICALLY
COLDEST TIME OF THE YEAR.
&&
.LONG TERM /SATURDAY NIGHT THROUGH FRIDAY/...
WE ARE IN FOR A MILD START TO THE EXTENDED PART OF THE FORECAST.
THE UPPER RIDGE MAINTAINS ITSELF INTO THE WEEKEND...WHICH RESULTS
IN THE APPROACHING COLD FRONT SLOWING DOWN AND BECOMING WAVY AS
IT INCHES EAST. THIS KEEPS US IN THE MILD AIR THROUGH AT LEAST
SUNDAY BEFORE THE COLD FRONT FINALLY REINTRODUCES THE COLD AIR
STARTING ON MONDAY.
MODELS ALL HAVE PRETTY GOOD TIMING AGREEMENT ON THE THIS INITIAL
FRONTAL BOUNDARY...BUT AS USUAL...DIFFERENCES ARISE AS WE GO OUT
IN TIME. THE GFS BRINGS A POTENT SURGE OF ARCTIC AIR OUR WAY FOR
LATER WED INTO THU...WHILE THE ECMWF/ECENS ARE SLOWER...AND CLOSER
TO THE END OF THE WEEK. THE GFS/GEFS ALSO SHOW A MORE SIGNIFICANT
EVENTUAL SOUTHWARD PLUNGE OF THE COLD AIR INTO THE EASTERN US
WHILE THE ECMWF/ECENS SUGGEST MORE OF A GLANCING BLOW WITH THE
BEST COLD CONFINED TO THE NERN US...ESPECIALLY NEW ENGLAND/NY.
SENSIBLE WEATHER WILL BE GOVERNED BY THE FRONT THAT WILL ONLY
SLOWLY MOVE OFF TO OUR SE AS IT STRUGGLES AGAINST THE BROAD SW
FLOW ALOFT IN THE STRONG UPPER RIDGE THAT WILL BE STUBBORN TO
RETREAT OFF THE SERN US. OPERATIONAL MODELS SUGGEST THE POTENTIAL
FOR AT LEAST ONE ADDITIONAL WAVE TO RIPPLE UP THAT FRONT FOR SOME
TIME LATER MONDAY INTO TUESDAY. WITH THE COLD AIR GETTING
CLOSER...THE NORTHERN EDGE OF THE PRECIP RUNS THE RISK OF BEING
SNOW...AS WOULD BE EXPECTED IN MOST NORMAL JANUARYS. IT IS TOO
FAR OUT TO GET FANCY SO THE FORECAST HAS RAIN OR SNOW AT THIS
RANGE...AND HOLDS OFF THE COLDEST AIR UNTIL LATE WEEK.
&&
.AVIATION /18Z FRIDAY THROUGH WEDNESDAY/...
WINDOW OF STRONGER WINDS IS SHRINKING AND ONLY A BRIEF PERIOD
EXISTS FOR GOOD MIXING OVER THE AREA. WILL THEREFORE KEEP WIND
SPEEDS LOWER THAN 10 KTS FOR MOST TERMINALS...AND LEAVE THEM ONLY
SLIGHTLY GUSTY IN THE WEST FOR 2-3 MORE HRS. LLWS STILL A CONCERN
INTO THE EARLY EVENING - UNTIL THE SHORT WAVE IS PAST US.
MULTIPLE BANDS OF SHOWERS HAVE CONGEALED INTO ONE MAJOR BAND/AREA
AND A WIDE AREA OF SCT/NMRS SHRA TO THE WEST. THE RETURNS ARE
MOVING STEADILY AND TIMING SUPPORTED BY LATEST HRRR SHUNTS MOST
OF THE RAIN TO THE EAST OF THE AREA BY 02Z. ALMOST NO RISK FOR
THUNDER NOW...SO NO MENTION PLACED INTO THE TAFS. RESIDUAL LOW LVL
MOISTURE AND A NEARLY CALM WIND AND A BIT OF COOLING WILL LIKELY
LEAD TO WIDESPREAD LOW CLOUDS/FOG OVERNIGHT. LATEST SREF/NAM AND GFS
FCSTS ALL SUPPORT THIS SCENARIO...INDICATING WIDESPREAD IFR CONDS
LIKELY. GFS MOS IS MUCH MORE OPTIMISTIC...BUT PREPONDERANCE OF
EVIDENCE POINTS TO LOW CLOUDS AND EVEN DRIZZLE PERSISTING INTO SAT
MORNING. THICK LOW CLOUDS LINGER FOR THE MORNING HOURS ON
SAT...AND MOST IF NOT ALL OF THE DAY IN THE EAST. A SFC LOW PASSES
WELL TO THE NORTH ON SUNDAY AND THE COLD FRONT ASSOCD WITH IT GOES
THRU VERY SLOWLY. AT LEAST ONE MORE WAVE OF LOW PRESSURE RIDES UP
FROM THE S ON MONDAY...GIVING LITTLE BREAK FROM A MONOTONOUS
MVFR/IFR FORECAST IN RAIN AND LOW CLOUDS/FOG.
OUTLOOK...
SUN...VFR SE...MVFR/IFR IN SHRA/CIGS NW.
MON...MVFR IN WIDESPREAD SH/RA.
MON NITE...CFROPA...NW/UPSLOPE FLOW SHSN.
TUE-WED...MAINLY VFR.
&&
.CTP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...DANGELO/LA CORTE
NEAR TERM...DANGELO
SHORT TERM...DANGELO/LA CORTE
LONG TERM...LA CORTE
AVIATION...DANGELO
AREA FORECAST DISCUSSION...UPDATED
NWS FORT WORTH TX
1131 AM CST FRI JAN 11 2013
.UPDATE...
NO FORECAST UPDATE WILL BE ISSUED HERE AT MIDDAY AS THE CURRENT
FORECAST FOR THE NEXT 24 HOURS IS ON TRACK.
CURRENTLY...THE FRONTAL TIMING FOR SATURDAY MORNING THROUGH EARLY
AFTERNOON...AND THE DEVELOPMENT OF CONVECTIVE ACTIVITY ASSOCIATED
WITH THE FRONT IS GOOD. OUR MAIN CONCERN REMAINS WITH THE
POTENTIAL FOR A BRIEF WINTRY MIX LATE SUNDAY NIGHT OVER THE
SOUTHEASTERN COUNTIES AS TEMPERATURES DROP INTO THE 30S. FORECAST
SOUNDINGS OVER THE SOUTHEAST COUNTIES ARE INDICATING THAT THE
PRECIPITATION MAY EXPERIENCE WET-BULB COOLING THAT COULD LEAD TO
SLEET MIXED WITH ANY LINGERING RAIN. HOWEVER...THIS MORNINGS GFS
KEEPS THE PRECIPITATION PROGRESSIVELY MOVING SOUTHEAST AND OUT OF
THE CWA BEFORE THIS TRANSITION CAN TAKE PLACE. AS SUCH...WE HAVE
NOT COMMITTED TO A WINTRY MIX AND WILL AWAIT TODAY/S ECMWF BEFORE
MAKING THE FINAL DECISION. 75
&&
.AVIATION...
TODAY SHOULD BE QUIET FOR THE AREA AIRPORTS. HIGH CLOUDS WILL
CONTINUE TO STREAM ACROSS THE AREA AND WINDS WILL BE BREEZY FROM
THE SOUTH. MVFR CIGS ARE EXPECTED LATE THIS EVENING AND OVERNIGHT
AHEAD OF AN APPROACHING COLD FRONT. HAVE BUMPED UP THE TIMING TO
4Z FOR THE METROPLEX AND 2Z FOR WACO...DUE TO LATEST RAP MODEL
SOUNDINGS. HAVE NOT GONE QUITE AS EARLY AS WHAT THE MODEL IS
SHOWING AS MOST OF THE CONSENSUS IS AFTER 06Z. FRONT SHOULD ARRIVE
TO THE AREA AIRPORTS BETWEEN 13Z AND 16Z. SCATTERED SHOWERS
ACTIVITY ARE LIKELY JUST AHEAD AND BEHIND THE FRONTAL BOUNDARY. WILL
KEEP THE WEATHER AS SHRA...DUE TO WEAK INSTABILITY. CANT RULE OUT
A THUNDERSTORM...ESPECIALLY FOR WACO...BUT PINPOINTING EXACT TIME
IS TOO DIFFICULT AT THIS TIME.
HAMPSHIRE
&&
.PREV DISCUSSION... /ISSUED 427 AM CST FRI JAN 11 2013/
THE LOW CLOUDS FINALLY CLEARED FROM THE REGION YESTERDAY EVENING
BUT HIGH CLOUDS HAVE BEEN SPREADING EAST ACROSS THE FORECAST AREA
OVERNIGHT. IT WILL BE MUCH WARMER TODAY AS SOUTHERLY WINDS
INCREASE DUE TO A TIGHTENING PRESSURE GRADIENT. AS A SHORTWAVE
THAT IS CURRENTLY OVER SOUTHERN CALIFORNIA MOVES EAST AND THEN
NORTHEAST DURING THE NEXT 24-48 HOURS...A COLD FRONT WILL MOVE
SOUTH INTO NORTH TEXAS AFTER MIDNIGHT TONIGHT...AND THROUGH THE
SOUTH BY MIDDAY SATURDAY. WE WILL SEE A CHANCE OF SHOWERS
DEVELOPING AFTER MIDNIGHT TONIGHT...AND A CHANCE OF SHOWERS AND
THUNDERSTORMS AREA WIDE SATURDAY. ALTHOUGH SEVERE WEATHER IS NOT
EXPECTED...A FEW STRONG STORMS WILL BE POSSIBLE ACROSS THE SOUTH.
RAIN CHANCES WILL CONTINUE SATURDAY NIGHT. RAIN CHANCES WILL SLOWLY
TAPER OFF FROM WEST TO EAST LATE SATURDAY NIGHT THROUGH SUNDAY
ACROSS ALL BUT THE SOUTHEAST. TEMPERATURES BY DAYBREAK SUNDAY MAY
APPROACH FREEZING SOME AREAS AS THE PRECIPITATION COMES TO AN END.
FOR NOW...HAVE NOT MENTIONED THE POSSIBILITY OF ANY LIGHT FREEZING
RAIN IN THE PUBLIC FORECAST. THE RAIN CHANCES ACROSS THE SOUTHEAST
WILL END BY LATE SUNDAY NIGHT.
THE ECMWF AND GFS STILL HAVE QUITE DIFFERENT SOLUTIONS AS TO WHAT
WILL HAPPEN WITH AN UPPER LEVEL TROUGH NEXT WEEK. THE ECMWF CUTS
OFF AN UPPER LEVEL LOW OVER ARIZONA AND THEN PUSHES IT EAST ACROSS
TEXAS WEDNESDAY NIGHT AND THURSDAY. IF THIS SOLUTION WERE TO
VERIFY IT WOULD MEAN A CHANCE FOR SOME WINTRY PRECIPITATION
THURSDAY. ON THE OTHER HAND THE GFS AND MOST...BUT NOT ALL...OF
ENSEMBLE SOLUTIONS KEEP THE REGION DRY. FOR NOW...HAVE KEPT THE
CLOUD COVER THROUGH THIS PERIOD OUT OF RESPECT FOR THE ECMWF AND
SOME OF THE GFS ENSEMBLE SOLUTIONS BUT LEFT OUT ANY MENTION OF
PRECIPITATION FOR THE WEDNESDAY NIGHT/THURSDAY SYSTEM. 58
&&
.PRELIMINARY POINT TEMPS/POPS...
DALLAS-FT. WORTH, TX 71 50 58 33 44 / 5 10 50 40 10
WACO, TX 71 52 62 33 47 / 5 20 50 40 20
PARIS, TX 69 51 61 34 45 / 5 20 80 60 30
DENTON, TX 71 48 56 31 44 / 5 10 50 30 10
MCKINNEY, TX 70 51 57 33 44 / 5 20 50 40 20
DALLAS, TX 71 53 58 34 44 / 5 20 50 40 20
TERRELL, TX 70 54 61 34 45 / 5 20 60 50 30
CORSICANA, TX 72 56 65 35 46 / 5 20 60 50 30
TEMPLE, TX 72 54 66 34 47 / 5 20 50 40 20
MINERAL WELLS, TX 74 45 54 28 44 / 5 10 40 20 10
&&
.FWD WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
/75
AREA FORECAST DISCUSSION...UPDATED
NWS FORT WORTH TX
1113 AM CST FRI JAN 11 2013
.AVIATION...
TODAY SHOULD BE QUIET FOR THE AREA AIRPORTS. HIGH CLOUDS WILL
CONTINUE TO STREAM ACROSS THE AREA AND WINDS WILL BE BREEZY FROM
THE SOUTH. MVFR CIGS ARE EXPECTED LATE THIS EVENING AND OVERNIGHT
AHEAD OF AN APPROACHING COLD FRONT. HAVE BUMPED UP THE TIMING TO
4Z FOR THE METROPLEX AND 2Z FOR WACO...DUE TO LATEST RAP MODEL
SOUNDINGS. HAVE NOT GONE QUITE AS EARLY AS WHAT THE MODEL IS
SHOWING AS MOST OF THE CONSENSUS IS AFTER 06Z. FRONT SHOULD ARRIVE
TO THE AREA AIRPORTS BETWEEN 13Z AND 16Z. SCATTERED SHOWERS
ACTIVITY ARE LIKELY JUST AHEAD AND BEHIND THE FRONTAL BOUNDARY. WILL
KEEP THE WEATHER AS SHRA...DUE TO WEAK INSTABILITY. CANT RULE OUT
A THUNDERSTORM...ESPECIALLY FOR WACO...BUT PINPOINTING EXACT TIME
IS TOO DIFFICULT AT THIS TIME.
HAMPSHIRE
&&
.PREV DISCUSSION... /ISSUED 427 AM CST FRI JAN 11 2013/
THE LOW CLOUDS FINALLY CLEARED FROM THE REGION YESTERDAY EVENING
BUT HIGH CLOUDS HAVE BEEN SPREADING EAST ACROSS THE FORECAST AREA
OVERNIGHT. IT WILL BE MUCH WARMER TODAY AS SOUTHERLY WINDS
INCREASE DUE TO A TIGHTENING PRESSURE GRADIENT. AS A SHORTWAVE
THAT IS CURRENTLY OVER SOUTHERN CALIFORNIA MOVES EAST AND THEN
NORTHEAST DURING THE NEXT 24-48 HOURS...A COLD FRONT WILL MOVE
SOUTH INTO NORTH TEXAS AFTER MIDNIGHT TONIGHT...AND THROUGH THE
SOUTH BY MIDDAY SATURDAY. WE WILL SEE A CHANCE OF SHOWERS
DEVELOPING AFTER MIDNIGHT TONIGHT...AND A CHANCE OF SHOWERS AND
THUNDERSTORMS AREA WIDE SATURDAY. ALTHOUGH SEVERE WEATHER IS NOT
EXPECTED...A FEW STRONG STORMS WILL BE POSSIBLE ACROSS THE SOUTH.
RAIN CHANCES WILL CONTINUE SATURDAY NIGHT. RAIN CHANCES WILL SLOWLY
TAPER OFF FROM WEST TO EAST LATE SATURDAY NIGHT THROUGH SUNDAY
ACROSS ALL BUT THE SOUTHEAST. TEMPERATURES BY DAYBREAK SUNDAY MAY
APPROACH FREEZING SOME AREAS AS THE PRECIPITATION COMES TO AN END.
FOR NOW...HAVE NOT MENTIONED THE POSSIBILITY OF ANY LIGHT FREEZING
RAIN IN THE PUBLIC FORECAST. THE RAIN CHANCES ACROSS THE SOUTHEAST
WILL END BY LATE SUNDAY NIGHT.
THE ECMWF AND GFS STILL HAVE QUITE DIFFERENT SOLUTIONS AS TO WHAT
WILL HAPPEN WITH AN UPPER LEVEL TROUGH NEXT WEEK. THE ECMWF CUTS
OFF AN UPPER LEVEL LOW OVER ARIZONA AND THEN PUSHES IT EAST ACROSS
TEXAS WEDNESDAY NIGHT AND THURSDAY. IF THIS SOLUTION WERE TO
VERIFY IT WOULD MEAN A CHANCE FOR SOME WINTRY PRECIPITATION
THURSDAY. ON THE OTHER HAND THE GFS AND MOST...BUT NOT ALL...OF
ENSEMBLE SOLUTIONS KEEP THE REGION DRY. FOR NOW...HAVE KEPT THE
CLOUD COVER THROUGH THIS PERIOD OUT OF RESPECT FOR THE ECMWF AND
SOME OF THE GFS ENSEMBLE SOLUTIONS BUT LEFT OUT ANY MENTION OF
PRECIPITATION FOR THE WEDNESDAY NIGHT/THURSDAY SYSTEM.
58
&&
.PRELIMINARY POINT TEMPS/POPS...
DALLAS-FT. WORTH, TX 71 50 58 33 44 / 5 10 50 40 10
WACO, TX 71 52 62 33 47 / 5 20 50 40 20
PARIS, TX 69 51 61 34 45 / 5 20 80 60 30
DENTON, TX 71 48 56 31 44 / 5 10 50 30 10
MCKINNEY, TX 70 51 57 33 44 / 5 20 50 40 20
DALLAS, TX 71 53 58 34 44 / 5 20 50 40 20
TERRELL, TX 70 54 61 34 45 / 5 20 60 50 30
CORSICANA, TX 72 56 65 35 46 / 5 20 60 50 30
TEMPLE, TX 72 54 66 34 47 / 5 20 50 40 20
MINERAL WELLS, TX 74 45 54 28 44 / 5 10 40 20 10
&&
.FWD WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
85/85
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
1157 AM CST FRI JAN 11 2013
.SHORT TERM...
1157 AM CST FRI JAN 11 2013
VISIBILITY HAS REMAINED LOW AT A QUARTER MILE OR LESS ACROSS THE
REGION AND HAS NOT IMPROVED MUCH AT ALL THROUGH THE MORNING WITH
TEMPERATURES STICKING AROUND THE MID 30S. THE INCREASING WINDS
APPEAR TO HAVE ACTUALLY MADE CONDITIONS WORSE WITH CREATING AN
ADVECTION FOG THAT IS ERODING MORE OF THE SNOW PACK. THE WORST
VISIBILITIES ARE NORTH OF A WARM FRONT THAT IS CURRENTLY IN SOUTHERN
IOWA AND EXPECT THAT TO BE THE CASE THROUGH THIS AFTERNOON AND
EVENING. THEREFORE...HAVE EXTENDED THE DENSE FOG ADVISORY THROUGH
MIDNIGHT. THAT TIMING COULD END UP BEING TOO LONG...OR TOO SHORT
DEPENDING ON WHAT OCCURS THIS EVENING. THE 11.16Z TO 11.19Z RUNS
OF THE HRRR HAVE DONE A GOOD JOB OF SHOWING THE LOWER
VISIBILITIES...PARTICULARLY WITH THE HINTING AT SLIGHTLY BETTER
CONDITIONS IN THE COULEES...AND SHOWS AN IMPROVEMENT FROM THE
SOUTH THIS EVENING AS THE WARM FRONT LIFTS NORTH. CURRENT THINKING
IS THAT VISIBILITY WILL IMPROVE FROM THE SOUTH TO NORTH BETWEEN
6PM TO MIDNIGHT TONIGHT WHERE WE CAN CANCEL THE ADVISORY EARLY IN
THE SOUTH IF THE CONDITIONS DO IN FACT IMPROVE. THE WILD CARD IS
THAT ONCE THE WARM FRONT MOVES THROUGH THAT THE STRONGER SOUTHWEST
WINDS AND WARMER AIR COULD JUST MAKE THINGS WORSE AGAIN WITH THE
ERODING SNOW PACK. FOR NOW...HAVE TRENDED TOWARD THE HRRR SINCE
THE OBS ACROSS SOUTHERN IOWA DO IMPROVE SUBSTANTIALLY SOUTH OF THE
FRONT. SHOULD THE DENSE FOG CONTINUE INTO THE OVERNIGHT HOURS...IT
DEFINITELY WILL COME TO AN END ONCE THE POTENT COLD FRONT COMES
THROUGH AND INCREASES WINDS INTO THE 25 TO 40 MPH RANGE.
.LONG TERM...SUNDAY NIGHT THROUGH THURSDAY
300 AM CST FRI JAN 11 2013
THE GFS AND 11.00Z ECMWF AGREE THAT THE POLAR VORTEX WILL BE
MOVING SOUTH FROM OVER NUNAVUT TO NEAR HUDSONS BAY. THIS WILL PUSH
A COLD FRONT ACROSS THE UPPER MIDWEST DURING THE MIDDLE OF NEXT
WEEK. THE GFS KEEPS THE SURFACE LOW OFF TO THE NORTHEAST OVER
ONTARIO AND IS QUICKER TO BRING THE FRONT THROUGH ON TUESDAY
NIGHT. THE ECMWF AND 11.00Z GEM INDICATE THE SURFACE LOW WILL MOVE
ACROSS THE UPPER MIDWEST AND GREAT LAKES AND DO NOT BRING THE
FRONT THROUGH UNTIL WEDNESDAY OR WEDNESDAY NIGHT. FOR NOW...WILL
STAY WITH THE MODEL CONSENSUS AND CARRY A CHANCE OF SNOW FOR
TUESDAY NIGHT AND WEDNESDAY.
&&
.AVIATION...THROUGH 18Z SATURDAY
1157 AM CST FRI JAN 11 2013
LOW VISIBILITY AND CEILINGS WILL PERSIST AT RST AND LSE THROUGH
TONIGHT AS A WARM AND MOIST AIR MASS SITS ACROSS THE REGION.
THE COMBINATION OF THIS AIR MASS WITH A MELTING SNOW PACK HAS LED
TO WIDESPREAD DENSE FOG WITH VISIBILITIES DROPPING TO A QUARTER
MILE OR LESS THROUGHOUT THE REGION. SOME OF THE RIVER VALLEY
LOCATIONS HAVE BEEN SLIGHTLY HIGHER WITH THE VISIBILITY AT TIMES
BUT CEILINGS HAVE REMAINED LOW AT A FEW HUNDRED FEET. LITTLE
CHANGE IN THESE CONDITIONS ARE EXPECTED THROUGH TONIGHT AS A WARM
FRONT MOVES IN FROM THE SOUTH AS A LOW PRESSURE SYSTEM TRACKS
THROUGH THE PLAINS ON INTO MINNESOTA. THERE MAY BE SOME
IMPROVEMENTS THIS EVENING AFTER THE WARM FRONT MOVES THROUGH...BUT
THE WARMER AIR AND STRONGER WINDS MAY JUST LEAD TO MOVE SNOW MELT
AND CONTINUED LOW VISIBILITIES. LOW LEVEL WINDS WILL BE
STRENGTHENING AHEAD OF A COLD FRONT THAT WILL MOVE THROUGH
OVERNIGHT...WITH LOW LEVEL WIND SHEAR OCCURRING FROM SFC WINDS
AROUND 15KTS AND 2KFT WINDS STRENGTHENING TO 50-60KTS. AFTER THE
COLD FRONT MOVES THROUGH...VISIBILITY AND CEILINGS WILL IMPROVE TO
MVFR BUT WINDS WILL RAPIDLY INCREASE TO BEING OUT OF THE WEST-
SOUTHWEST AT 20-35KTS. THE BACK EDGE OF THE SYSTEM WILL THEN MOVE
THROUGH TOMORROW MORNING WITH SOME SNOW POSSIBLE THAT COULD BRING
VISIBILITY BACK DOWN TO IFR.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
1157 AM CST FRI JAN 11 2013
WI...DENSE FOG ADVISORY UNTIL MIDNIGHT CST TONIGHT FOR WIZ017-029-
032>034-041>044-053>055-061.
MN...DENSE FOG ADVISORY UNTIL MIDNIGHT CST TONIGHT FOR MNZ079-086>088-
094>096.
IA...DENSE FOG ADVISORY UNTIL MIDNIGHT CST TONIGHT FOR IAZ008>011-018-
019-029-030.
&&
$$
SHORT TERM...HALBACH
LONG TERM...04
AVIATION...HALBACH