Forecast Discussions mentioning any of
"HRRR" "RAP" "RR" "RUC13" "RUC" received at GSD on 02/13/13
AREA FORECAST DISCUSSION
NWS TUCSON AZ
930 AM MST MON FEB 11 2013
.SYNOPSIS...A STRONG AND COLD STORM SYSTEM ACROSS NORTHWEST ARIZONA
WILL TRACK ACROSS SOUTHEAST ARIZONA THIS AFTERNOON AND EVENING...
RESULTING IN A CHANCE OF VALLEY RAIN AND POSSIBLY LOW ELEVATION
SNOWFALL. COLD TEMPERATURES WILL PREVAIL THROUGH TUESDAY FOLLOWED BY
DRY CONDITIONS AND A WARMING TREND WEDNESDAY THROUGH SUNDAY.
&&
.DISCUSSION...WATER VAPOR IMAGERY SHOWS AN UPPER LOW OVER PORTIONS
OF THE CENTRAL ROCKIES WITH THE TROUGH AXIS EXTENDING SOUTHWEST
ACROSS NORTHWEST ARIZONA AND INTO EXTREME SOUTHEAST CALIFORNIA. THE
NEXT IMPULSE WITH THIS SYSTEM THAT WILL BRING THE POTENTIAL FOR RAIN
AND MOSTLY MOUNTAIN SNOW IS JUST ENTERING WESTERN ARIZONA AT THIS
TIME. IR SATELLITE IMAGERY SHOWS A BAND OF EXTENSIVE CLOUDINESS
EXTENDING FROM NORTHWEST NEW MEXICO AND ACROSS CENTRAL ARIZONA WITH
THE CENTRAL AND EASTERN PORTIONS OF MY FORECAST AREA STILL CLOUD
FREE. HOWEVER...TO THE WEST OVER EXTREME WESTERN AND CENTRAL
PORTIONS OF PIMA COUNTY...MID LEVEL CLOUDS ARE CONTINUING TO DEVELOP
AND THESE WILL MOVE EAST AND SOUTHEAST AS THE MORNING PROGRESSES.
THIS MORNINGS KTWC SOUNDING REVEALED A CONTINUED DRY SOUNDING WITH
PRECIPITABLE WATER VALUES VIRTUALLY IDENTICAL TO LAST EVENINGS
SOUNDING WITH A VALUE THIS MORNING OF 0.19 INCHES. NEEDLESS TO
SAY...THE AIRMASS HAS NOT MOISTENED QUITE AS MUCH AS WAS EXPECTED
LAST EVENING. THE 00Z NAM SHOWED LESS THAN 10 PERCENT POP FOR THIS
AFTERNOON FOR TUCSON...BUT 61 PERCENT POP BETWEEN 00Z AND 06Z THIS
EVENING. HOWEVER...THE 12Z RUN OF THE NAM NOW SHOWS 27 PERCENT POP
FOR TUCSON THIS AFTERNOON AND VIRTUALLY ZERO AFTER 00Z. IN
ADDITION...THE HRRR (HIGH RESOLUTION RAPID REFRESH) MODEL SHOWS A
BAND OF PRECIPITATION MOVING ACROSS THE TUCSON METRO AREA BETWEEN
AROUND 3 PM TO 6 PM THIS AFTERNOON. THE GFS MOS POP SHOWS ABOUT A 30
PERCENT POP FOR THE MIDDLE TO LATTER PORTION OF THIS AFTERNOON.
THE LATEST RADAR MOSAIC AND SURFACE OBSERVATIONS SHOW A BAND OF
SHOWERS EXTENDING FROM THE MOGOLLON RIM AREA AND SOUTHWEST ACROSS
THE PHOENIX METRO. ANOTHER BATCH OF PRECIPITATION IS MOVING ACROSS
THE EXTREME SOUTHWESTERN PORTION OF ARIZONA EAST OF BLYTHE. CLOSER
TO HOME...NOT MUCH ACTIVITY OVER MY FORECAST AREA...YET. THAT
SAID...THE INHERITED 40 PERCENT POP FOR THIS AFTERNOON SEEMS
REASONABLE...SO NO CHANGES ARE PLANNED TO THE POP FORECAST FOR THE
REST OF TODAY. HOWEVER...WILL CONTINUE TO MONITOR SATELLITE AND
RADAR TRENDS THROUGH THE REMAINDER OF THE MORNING AND INTO THE
AFTERNOON AND WILL MAKE ADJUSTMENTS IF NEEDED.
INHERITED SNOW AMOUNTS FROM THE NIGHT SHIFT WITH THIS SYSTEM ARE
INDICATING AMOUNTS WELL BELOW ADVISORY CRITERIA WITH ABOUT 3 TO 5
INCHES OVER THE WHITE MOUNTAINS AND 2 TO 4 INCHES FOR THE SANTA
CATALINA`S OF NORTHEAST PIMA COUNTY AND THE PINALENO`S OF GRAHAM
COUNTY.
THE TEMPERATURES AS OF 16Z (9 AM MST)...RANGE FROM THE UPPER 30S TO
THE LOWER 40S AND THESE READINGS SEEM TO BE ON TRACK WITH EXPECTED
AFTERNOON HIGHS...SO NO CHANGES PLANNED AT THIS TIME.
&&
.AVIATION...CLOUDS INCREASING FROM NORTH TO SOUTH ACROSS SOUTHEAST
ARIZONA TODAY. EXPECT SCT-BKN CLOUDS AT 5-8K FT AGL DEVELOPING
AREAWIDE BETWEEN 11/17Z-11/20Z TODAY. MVFR CIGS/VSBYS AND MOUNTAIN
OBSCURATIONS IN SHSN IN THE WHITE MOUNTAINS DEVELOPING AFT 11/17Z
WITH SCT VALLEY SHRA/MOUNTAIN SHSN ELSEWHERE. SURFACE WIND LESS THAN
10 KTS THRU 11/14Z...THEN INCREASING SURFACE WIND...WITH SWLY/WLY
SURFACE WIND AT 15-20 KTS AND GUSTS TO 20-30 KTS AFT 11/18Z. SURFACE
WIND DIMINISHING AFT 12/03Z...AND GENERALLY LESS THAN 10 KTS BY
12/06Z. ELEVATED SURFACE WIND CONTINUING IN THE GILA RIVER VALLEY ON
TUESDAY. AVIATION DISCUSSION NOT UPDATED FOR TAF AMENDMENTS.
&&
.FIRE WEATHER...A STORM SYSTEM WILL RESULT IN A CHANCE OF VALLEY
RAIN AND MOUNTAIN SNOW SHOWERS TODAY AND TONIGHT...MAINLY FROM
TUCSON EAST AND NORTHEAST. THIS SYSTEM WILL ALSO BRING STRONG AND
GUSTY WINDS TODAY...CONTINUING IN THE GILA RIVER VALLEY TUESDAY. A
WARMING TREND WILL THEN BEGIN ON WEDNESDAY...PERSISTING THROUGH
SUNDAY.
&&
.TWC WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
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AREA FORECAST DISCUSSION
NWS EUREKA CA
347 PM PST TUE FEB 12 2013
.SYNOPSIS...A STRONG AND PERSISTENT RIDGE OF HIGH PRESSURE WILL
KEEP NORTHWEST CALIFORNIA DRY THROUGH FRIDAY. HOWEVER COASTAL
LOCATIONS WILL SEE PERIODS OF LOW CLOUDS AND FOG THROUGH THURSDAY
MORNING. INTERIOR AREAS WILL STAY SUNNY OUTSIDE OF AREAS OF
VALLEY FOG.
&&
.SHORT TERM...TONIGHT THROUGH FRIDAY NIGHT...A RIDGE OF HIGH
PRESSURE CONTINUES TO SIT OFF THE WEST COAST MAINTAINING DEEP
NORTHERLY FLOW OVER THE AREA. WEAK SHORTWAVES WILL MOVE SOUTH ALONG THE
WEST COAST ON THE EAST SIDE OF THIS RIDGE BRINGING IMPULSES OF
INCREASED BOUNDARY LAYER MOISTURE TO COASTAL LOCATIONS PRIMARILY
NORTH OF THE CAPE. A FIRST SHORTWAVE IS CURRENTLY MOVING OVER
NORTHERN CALIFORNIA...AND HAS RESULTED IN AN EXPANDING FIELD OF
STRATUS DEVELOPING FROM ORICK SOUTH TO THE CAPE. EXPECT THIS AREA OF
STRATUS TO CONTINUE TO EXPAND THROUGH THE REMAINDER OF THE EVENING
AND OVERNIGHT...POSSIBLY STRETCHING NORTH INTO DEL NORTE COUNTY AS
ADDITIONAL CLOUDS MOVE SOUTH FROM OFF THE OREGON COAST. A SECOND
REINFORCING SHORTWAVE WILL ADVANCE DOWN THE COAST ON THURSDAY WHICH
MAY ALLOW CLOUD COVER TO PERSIST ALONG COASTAL AREAS NORTH OF THE
CAPE...BUT WITH WEAK OFFSHORE FLOW EXPECTED LATE WEDNESDAY MORNING
AND EARLY AFTERNOON...HAVE OPTED TO CONTINUE A FORECAST FOR A SHORT
PERIOD OF CLEARING WEDNESDAY FOR ALL AREAS BEFORE THE STRATUS
REDEVELOPS WEDNESDAY EVENING. INTERIOR AREAS WILL CONTINUE TO SEE
OVERNIGHT AND MORNING FOG...DISSIPATING BY LATE MORNING OR EARLY
AFTERNOON. COASTAL CLOUDS WILL BE LESS NUMEROUS SOUTH OF THE CAPE
WHERE OFFSHORE FLOW WILL PERSIST...BUT CAN NOT DISCOUNT THE
DEVELOPMENT COMPLETELY.
AS THE RIDGE BUILDS EAST OVER THE WEST COAST WEDNESDAY NIGHT INTO
THURSDAY THE LOW LEVEL INVERSION SHOULD STRENGTHEN AND DESCEND
LEADING TO A MORE COMPACT MARINE LAYER AND HIGHER PROBABILITIES OF
FOG ALONG THE COAST. BY LATE THURSDAY THE THERMAL TROUGH WILL BEGIN
TO MOVE WEST OFF THE COAST AS THE UPPER LEVEL RIDGE MOVES EAST INTO
THE PACIFIC NORTHWEST. THIS WILL ENHANCE OFFSHORE FLOW AND LEAD TO
CLEARING SKIES. OFFSHORE FLOW LATE THURSDAY AFTERNOON AND AGAIN
FRIDAY WILL BRING ABOVE NORMAL TEMPERATURES TO MOST OF NORTHWEST
CALIFORNIA WITH 60 DEGREE TEMPERATURES POSSIBLE EVEN ALONG THE
IMMEDIATE COAST. THE THERMAL TROUGH WILL THEN SHIFT BACK INLAND LATE
FRIDAY AFTERNOON INTO FRIDAY NIGHT WITH RETURN LIGHT SOUTHERLY FLOW
POSSIBLY DEVELOPING AHEAD OF AN APPROACHING UPPER TROUGH. IT IS
STARTING TO LOOK MORE LIKELY THAT COASTAL CLOUDS MAY RETURN BY LATE
FRIDAY AFTERNOON OR OVERNIGHT NORTH OF THE CAPE AS THE SOUTHERLY
FLOW DEVELOPS. OTHERWISE DRY AND CLEAR CONDITIONS WILL PERSIST FOR
THE REMAINDER OF NORTHWEST CALIFORNIA THROUGH FRIDAY NIGHT. RPA
.LONG TERM...SATURDAY THROUGH MID NEXT WEEK...THE SYNOPTIC PATTERN
WILL BECOME MUCH MORE PROGRESSIVE HEADING THROUGH THIS WEEKEND. THE
PERSISTENT RIDGE OVER THE EASTERN PACIFIC WILL GIVE WAY TO A SERIES
OF STORM SYSTEMS TRACKING FROM THE ALEUTIANS TO THE GULF OF
ALASKA...AND EVENTUALLY IMPACTING THE PACIFIC NORTHWEST. THE FIRST
SUCH SYSTEM WILL TRACK WELL TO OUR NORTH WITH PERHAPS JUST THE
SOUTHERN END OF ITS COLD FRONT CLIPPING NORTHWEST CALIFORNIA LATE
SATURDAY. MODELS ARE COMING INTO BETTER AGREEMENT AND SEEM TO BE
SETTLING ON THIS SOLUTION...WHICH WOULD MEAN JUST A COUPLE OF
SHOWERS FOR THE NORTH COAST SATURDAY AFTERNOON. THIS COULD LINGER
INTO SATURDAY NIGHT BUT AT THIS POINT SUNDAY IS LOOKING MOSTLY DRY
AND SUNNY ALBEIT A BIT COOLER. ANOTHER SHORTWAVE MAY PASS THROUGH
LATE MONDAY WITH SIMILAR IMPACT BUT SLIGHTLY MORE MOISTURE...AHEAD
OF A MORE SIGNIFICANT SYSTEM SET TO IMPACT NORTHWEST CALIFORNIA
TUESDAY. THIS STORM COULD BRING RELATIVELY LOW SNOW LEVELS AND
COLDER TEMPERATURES ALONG WITH A GOOD CHANCE OF RAIN AND HAIL
SHOWERS AT THE COAST. AAD
&&
.AVIATION...MORE MOISTURE POOLING OCCURRING ON WINDWARD SIDE OF CAPE
MENDOCINO GENERALLY ALONG THE COAST WITH PERSISTENT N WINDS PUSHING
THE LOW CLOUDS AND FOG DOWNWIND WELL PAST THE CAPE AND FARTHER
OFFSHORE. DOWNSLOPING N OF KACV IS KEEPING THAT TERMINAL MOSTLY
CLEAR FOR NOW. EXPECT AS LAND-BASED WINDS DECREASE THIS EVENING...
SCT TO PERHAPS BKN LOW CLOUDS MAY FILL IN THERE. BOTH THE NAM AND
THE RUC HAVE BECOME MORE BULLISH WITH REDUCED VSBYS LATER TONIGHT AT
KACV. FOR NOW...HAVE KEPT MINIMUM VSBYS AT 4SM WITH CIGS BETWEEN 04Z
AND 15Z. A MODERATE TO HIGH LEVEL OF UNCERTAINTY EXISTS WITH THIS
FORECAST. HAVE KEPT KCEC AS VFR OVERNIGHT WITH A HINT OF LOW
CLOUDINESS AND LIGHT FOG. THIS WILL NEED TO BE MONITORED CLOSELY.
/SEC
&&
.MARINE...LITTLE TO CHANGE WITH EXISTING FORECAST PACKAGE. N WINDS
HAVE DIMINISHED IN THE PAST 24 HRS...BUT SMALL CRAFT ADVISORY
CONDITIONS CONTINUE IN ALL BUT THE NEAR SHORE S LEG. EVEN THERE...
WIND GUSTS TO 30 KTS REMAIN POSSIBLE THRU THE EVENING DOWNWIND FROM
PROMINENT CAPES. WINDS WILL INCREASE AGAIN WED NIGHT...THEN DECREASE
AGAIN BY LATE IN THE WORK WEEK. PRESENT LONG PERIOD WAVE GROUP WILL
CONTINUE TO DECAY THRU WED. FORERUNNERS FROM ANOTHER WAVE GROUP WILL
ENTER THE AREA LATE WED WITH WAVES BUILDING AND PERIODS DECREASING
INTO LATE WEEK. A 3RD WAVE TRAIN WILL ARRIVE LATE FRI OR EARLY SAT.
/SEC
&&
.EKA WATCHES/WARNINGS/ADVISORIES...
CA...NONE.
NORTHWEST CALIFORNIA COASTAL WATERS...
SMALL CRAFT ADVISORY UNTIL 9 PM PST THIS EVENING PZZ450.
SMALL CRAFT ADVISORY UNTIL 3 AM PST WEDNESDAY PZZ470.
SMALL CRAFT ADVISORY UNTIL 9 AM PST FRIDAY PZZ475.
&&
$$
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AREA FORECAST DISCUSSION
NWS GRAND JUNCTION CO
607 AM MST MON FEB 11 2013
.UPDATE...
ISSUED AT 602 AM MST MON FEB 11 2013
NICELY WOUND UP LOW/VORTICITY CENTER HAS STARTED TO SHEER APART
PER LATEST SATELLITE IMAGERY AND SHOWING SIGNS OF THIS ON LATEST
RADAR RETURNS AS WELL. LATEST 3KM HRRR REFLECTIVITY FORECAST
GRABBING ONTO THIS AND INDICATING THE EARLIER BAND OF HEAVIER
SNOWFALL RESPONSIBLE FOR 2 INCHES OF SNOW IN THE GRAND VALLEY AND
NUCLA REGIONS WILL BE TRENDING DOWN...WITH SNOW SHOWERS BECOMING
MORE SCATTERED IN NATURE FOR AREAS ALONG AND NORTH OF INTERSTATE
70. AS A RESULT...HAVE WENT AHEAD AND ALLOWED THE WINTER STORM
WARNINGS EXPIRE FOR THESE AREAS AS OF 6 AM MST. STILL SHOULD SEE
ANOTHER INCH OR TWO IN A FEW AREAS...BUT OVERALL COVERAGE WILL BE
DIMINISHED. AWAITING SUNRISE BEFORE MAKING FINAL CALL ON OTHER
HIGHLIGHTS...ALTHOUGH IR IMAGERY SUGGESTS WE MAY BE MAKING MORE
ADJUSTMENTS TO SOUTHERN HIGHLIGHTS AS THE DAY WEARS ON.
&&
.SHORT TERM...(TODAY THROUGH TUESDAY)
ISSUED AT 326 AM MST MON FEB 11 2013
MESSY FORECAST SITUATION THIS WITH QUICKLY CHANGING CONDITIONS
ACROSS THE REGION. THE 700-600MB LOW...THAT IS KEY TO THE HIGHLIGHTS
IN THE FOUR CORNERS ZONES...WAS PROGGED DIFFERENTLY TONIGHT. IT IS
SITUATED FURTHER NORTH THAN PREVIOUSLY PROGGED. IT SPUN NEAR
CANYONLANDS NATIONAL PARK THROUGH MUCH OF THE NIGHT AND WILL
PROGRESS SOUTH OF THE I-70 CORRIDOR TODAY. ON THE WEST EDGE OF THE
ASSOCIATED BAROCLINIC LEAF...VERY HEAVY SNOW BANDS HAVE FORMED. IN
NUCLA AND GRAND JUNCTION TWO INCHES FELL IN JUST OVER ONE HOUR WITH
VISIBILITY DOWN TO 1/4 MILE. THIS AREA OF HEAVY SNOW WILL MARCH EAST
DOWN THE I-70 CORRIDOR THIS MORNING REACHING RIFLE AROUND 5 AM...
GLENWOOD SPRINGS TO ASPEN AROUND 7 AM AND EAGLE AROUND 8 AM.
ENHANCED CLOUD TOPS ARE SPREADING BACK ACROSS THE NW COLORADO ZONES
WHERE LIGHT SNOWFALL WILL CONTINUE THIS MORNING. HIGHLIGHTS WILL
LIKELY COME DOWN AT 6 AM AS CURRENTLY TIMED BUT ANOTHER 2-4 INCHES
MAY FALL IN THE NORTHERN MTNS TODAY.
FURTHER SOUTH...TIGHT LOW LEVEL CYCLONIC ROTATION AND FAVORABLE
SOUTHWEST FLOW OROGRAPHICS WILL CONTINUE TO PRODUCE ACCUMULATING
SNOW FOR SOUTHEAST UTAH AND SOUTHWEST COLORADO. SNOW AMOUNTS THERE
WILL LIKELY BE CLOSER TO 3-6 INCHES IN CEZ-DRO-PSO VALLEYS.
THE MID LEVEL LOW SHIFTS EAST OF THE CONTINENTAL DIVIDE LATE THIS
AFTERNOON AND THE LAST SNOW SHOWERS OF THIS STORM END BY MIDNIGHT.
A COLD NIGHT EXPECTED MONDAY NIGHT UNDER CLEARING SKIES...LIGHT
NORTH WINDS...AND 700MB TEMPS AT -14C. AREAS OF FREEZING FOG ARE
POSSIBLE. TUESDAY...A TRANSIENT RIDGE PASSES FROM NORTH TO SOUTH
PRODUCING WARM ADVECTION ALOFT AND CAPPED VALLEYS.
.LONG TERM...(TUESDAY NIGHT THROUGH SUNDAY)
ISSUED AT 326 AM MST MON FEB 11 2013
DIRTY NORTH TO NORTHWEST FLOW ALOFT WILL BE SETTING UP OVER THE
FORECAST AREA TUESDAY NIGHT AND PERSIST THROUGH THE END OF THE
WEEK. THIS WILL BRING A FEW ROUNDS OF SNOW TO THE NORTHERN AND
CENTRAL MOUNTAINS...GENERALLY FROM VAIL PASS NORTHWARD...AS WEAK
WAVES PUSH THROUGH. THE STRONGEST IN THIS SERIES ARRIVES WEDNESDAY
NIGHT AND THURSDAY...AND HAVE BOOSTED POPS UP INTO THE LOW LIKELY
CATEGORIES FOR THE FLAT TOPS AND THE PARK RANGE. THIS WAVE WILL
DRIVE THE MOISTURE A BIT FURTHER SOUTH...IMPACTING THE SAN JUANS AS
WELL...BUT MODELS HAVE BEEN TRENDING WEAKER WITH EACH RUN...SO
WILL NOT JUMP POPS UP MUCH AT THIS TIME. HEIGHTS START CLIMBING BY
FRIDAY AFTERNOON...WITH DRY CONDITIONS EXPECTED AS WE WORK INTO
THE WEEKEND. TEMPERATURES WILL BE RUNNING COOLER THAN NORMAL THIS
WEEK...WITH GRADUAL WARMING INTO THE WEEKEND.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z TUESDAY MORNING)
ISSUED AT 326 AM MST MON FEB 11 2013
ACROSS THE NORTH INCLUDING KVEL KCAG KHDN KSBS SCATTERED SNOW
SHOWERS WILL PRODUCE BRIEF MVFR CEILINGS THROUGH 21Z. OTHERWISE
VFR CONDITIONS WILL DOMINATE. WIDESPREAD FOG MAY PERSIST IN THE
VCNTY OF KVEL UNTIL 18Z. AND VALLEY FOG IS POSSIBLE AFTER 06Z
TONIGHT
FURTHER SOUTH SNOW SHOWERS WILL BE WIDESPREAD THROUGH THIS
AFTERNOON. MOUNTAIN OBSCURATIONS WITH POOR FLIGHT CONDITIONS WILL
BE WIDESPREAD OVER THE SOUTHERN MOUNTAINS AND OCCASIONAL OVER THE
CENTRAL MOUNTAINS. LOW CEILINGS WILL PRODUCE MVFR/IFR CONDITIONS
AT TIMES OVER THE SOUTHERN AIRPORTS INCLUDING KCEZ KDRO KPSO.
THESE TAF SITES MAY BE IMPACTED AT TIMES WITH MVFR AND POSSIBLY
EVEN BRIEF IFR CONDITIONS IN SNOW SHOWERS...LOW CLOUDS AND/OR FOG.
KRIL KASE KEGE WILL HAVE 1-2 HOURS OF LIFR CONDITIONS IN HEAVY
SNOW THIS MORNING BETWEEN 12-15Z. TAF SITES WILL SEE A DECREASING
CHANCE OF SNOW THIS AFTERNOON WITH VFR CONDITIONS EXPECTED FOR ALL
TAF SITES AFTER 06Z TONIGHT. AREAS OF VALLEY FOG ARE POSSIBLE
AFTER 06Z TONIGHT.
&&
.GJT WATCHES/WARNINGS/ADVISORIES...
CO...WINTER STORM WARNING UNTIL MIDNIGHT MST TONIGHT FOR COZ018-019-
021>023.
WINTER STORM WARNING UNTIL NOON MST TODAY FOR COZ009-012-017.
UT...WINTER STORM WARNING UNTIL NOON MST TODAY FOR UTZ028.
WINTER WEATHER ADVISORY UNTIL 6 PM MST THIS EVENING FOR UTZ022-
029.
&&
$$
UPDATE...JDC
SHORT TERM...JOE
LONG TERM...JDC
AVIATION...JOE
AREA FORECAST DISCUSSION
NWS TAUNTON MA
701 PM EST TUE FEB 12 2013
.SYNOPSIS...
BLUSTERY WEST WINDS DIMINISH TONIGHT. DRY WEATHER PREVAILS THROUGH
WEDNESDAY WITH SEASONABLE TEMPERATURES. A QUICK MOVING OCEAN STORM
MAY BRING MINOR SNOW ACCUMULATIONS WEDNESDAY NIGHT TO THE SOUTH
COAST OF MASSACHUSETTS AND RHODE ISLAND...INCLUDING CAPE COD AND
THE ISLANDS. A CLIPPER LOW MAY BRING SNOW SHOWERS SAT. BLUSTERY
AND UNSEASONABLY COLD WEATHER FOLLOWS SUNDAY INTO MONDAY.
&&
.NEAR TERM /UNTIL 6 AM WEDNESDAY MORNING/...
7 PM UPDATE...
WV IMAGERY SHOWS WEAK FAST MOVING SHORTWAVE MOVING THROUGH NY
WHICH IS EXPECTED TO CROSS THE REGION DURING THE EARLY HALF OF THE
OVERNIGHT. THIS MAY HELP REINFORCE SOME OF THE MID LVL COLD
ADVECTION...MAINTAINING THE SC FIELD AND KEEPING THE WINDS
SOMEWHAT ELEVATED. HOWEVER...GIVEN THE LACK OF
SUNSHINE...WINDS/CLOUDS STILL GENERALLY DIMINISH
SOMEWHAT...ACCELERATING MORE-SO AFTER ABOUT 06Z /1 AM/ AS THE WAVE
MOVES E. HAVE TRENDED SKIES/WIND FORECAST FOR THE OVERNIGHT TOWARD
THIS THINKING/TIMING. RAP WAS USED AS A BASELINE AS IT SEEMED TO
FIT THIS IDEA. ALSO ADJUSTED TEMPS/DWPTS TO BRING THEM UP TO
TRENDS.
&&
.SHORT TERM /6 AM WEDNESDAY MORNING THROUGH WEDNESDAY NIGHT/...
WEDNESDAY...
SUFFICIENT SHORT WAVE RIDGING OVER THE REGION FOR AT LEAST PARTIAL
SUNSHINE. WILL LIKELY SEE SOME MID/HIGH WAA CLOUDS ARRIVE ON THE
SW HORIZON AS MID LEVEL TROUGH APPROACHES. FAIRLY NICE DAY BY MID
FEB STANDARDS WITH SUNSHINE/TEMPS 35-40 AND LIGHT WINDS.
WED NIGHT...
12Z MODEL GUIDANCE HAS TRENDED FARTHER OFFSHORE WITH SHORT WAVE
TROUGH AND ASSOCIATED SURFACE LOW. THE EXCEPTION IS THE NAM WHICH
IS MORE ROBUST WITH ITS MID LEVEL TROUGH WHICH RESULTS IN MORE
SHORT WAVE RIDGING...YIELDING A MORE NORTHWARD SOLUTION. A
POSSIBLE RED FLAG FOR THE 12Z NAM IS THE NEW 15Z SREF WHICH
SUPPORTS THE MORE SOUTHERN SOLUTION OF THE EC. THE ECMWF HAS
SHOWN GREAT RUN TO RUN CONSISTENCY SO WE FOLLOWED ITS SOLUTION FOR
THIS FORECAST.
THIS RESULTS IN SNOW ACCUMULATIONS CONFINED TO THE SOUTH COAST OF
MA AND RI INCLUDING CAPE COD AND THE ISLANDS. CURRENT THINKING 1-2
INCHES ACROSS THIS AREA WITH LESS THAN AN INCH ACROSS NORTHERN
PORTIONS OF CT/RI INTO INTERIOR SOUTHEAST MA. LITTLE IF ANY
ACCUMULATION NORTH OF THE MA PIKE. WE WILL HAVE TO WATCH LATER
RUNS FOR A POSSIBLE FARTHER OFFSHORE TRACK WHICH WOULD YIELD
LITTLE IF ANY SNOW ACCUMULATIONS ANYWHERE INCLUDING THE SOUTH
COAST.
&&
.LONG TERM /THURSDAY THROUGH TUESDAY/...
HEADLINES...
* CLIPPER LOW MAY BRING SOME LIGHT SNOW TO THE REGION SATURDAY
* DEVELOPING OFFSHORE LOOKS TO REMAIN OFFSHORE SAT/SUN
* COLDER AIR BUILDS ACROSS THE REGION FOR THE EARLY PART OF NEXT WEEK
* A RETURN TO MILDER CONDITIONS IS POSSIBLE BY MIDWEEK
OVERVIEW AND MODEL PREFERENCES...
GIVEN THE MODEL SPREAD ON THE CPC TELECONNECTIONS...MODELS MAY BE
STRUGGLING WITH A LATE WEAK SHIFT TO VERY MERIDIONAL FLOW WITH
BROAD DEEP TROF SETTLING OVER THE GREAT LAKES TO NEW ENGLAND AND
VERY STRING RIDGING OFFSHORE. NONETHELESS...12/12Z ECMWF STILL
VERY CONSISTENT IN ITS SYNOPTIC PATTERN AS IT HAS BEEN FOR
SEVERAL RUNS NOW. INDEED...EVEN THE SLIGHTLY MORE PROGRESSIVE
12/12Z GFS IS GRADUALLY TRENDING TOWARD THE ECMWF SOLUTION WITH
EVERY RUN. WITH THIS IN MIND...LIKE THE PREVIOUS SHIFT/S THINKING
IN LEANING TOWARD A ECMWF SOLUTION. WILL CONTINUE THIS TREND FOR
THIS UPDATE DESPITE THE METEOROLOGICAL SQUEEZE PLAY OVER SRN NEW
ENGLAND BETWEEN THE STRONG TROF AND RIDGE AND THE MODEL SPREAD
REGARDING IT.
DETAILS...
THU INTO FRI...
MOSTLY DRY AFTER EARLY MORNING SNOW OVER SRN PORTIONS OF THE
FORECAST AREA SHIFTS S BY MID DAY THU. THIS TREND TOWARD DRYING IS
THANKS TO WEAK MID LVL RIDGING IN ADVANCE OF THE DIGGING LONGWAVE
TROF TO THE W. THEREFORE...DESPITE A COOL START WITH N-NW FLOW THE
GRADUAL TREND WILL BE TOWARD WARMING INTO FRI AS SW FLOW SETS UP E
OF THE TROF. MAYBE AN ISOLATED -SHSN/SHRA LATE FRI WITH A WEAK
WARM FRONTAL PASSAGE...BUT SOUNDINGS REMAIN QUITE DRY SO WILL
CONTINUE WITH THIS THINKING.
FRI NIGHT INTO SAT...
CLIPPER SYSTEM PASSES WELL NW OF THE REGION. AS PREVIOUS SHIFT
NOTED...CLIMATOLOGICAL THIS IS THE UNFAVORABLE CLIPPER TRACK FOR
PRECIPITATION...AND THIS ENHANCED BY AN ALREADY DRY COLUMN.
THEREFORE...WILL ERR TOWARD ONLY SLIGHT TO CHANCE POPS WITH COLD
FROPA ASSOCIATED WITH THIS LOW EARLY SAT...BUT THERE IS THE CHANCE
IT COULD REMAIN MOSTLY DRY EVERYWHERE.
SUN INTO MON...
ONE ENHANCEMENT THIS COLD FRONT WILL LEAD TO HOWEVER...IS
USHERING IN A MUCH COLDER AIRMASS. H5 HEIGHTS DROP SIGNIFICANTLY
TO ABOUT 520 DM OR LOWER WITH H85 TEMPS IN THE -15 TO -20C RANGE.
THEREFORE A BRIEF COLD SNAP AS THE LONGWAVE TROF SLOWLY SHIFTS
OVER THANKS TO A WEAKENING OF THE ATLANTIC RIDGE. GIVEN THIS
SHIFT...SUSPECT THAT ECMWF SUGGESTION THAT LOW PRES REMAINS WELL
OFFSHORE SUN REMAINS A BETTER FORECAST...AND WILL CONTINUE WITH A
MOSTLY DRY FORECAST WITH STRONG HIGH PRES AND COOL AIRMASS.
TUE INTO WED...
A FAIR AMOUNT OF UNCERTAINTY HERE...BUT WITH LONGWAVE TROF
SHIFTING E AND GRADUALLY OPENING...GUIDANCE FAVORS BROAD RIDGE
BUILDING OVER THE ERN CONUS WITH A WARMING TREND. GUIDANCE ALSO
TRYING TO BRING A VERY ROBUST LOW PRES INTO THE ST. LAWRENCE
VALLEY BY TUE NIGHT...BUT GIVEN THE UNCERTAINTY WILL KEEP ANY POPS
LOW.
&&
.AVIATION /23Z TUESDAY THROUGH SUNDAY/...
FORECASTER CONFIDENCE LEVELS...
LOW...LESS THAN 30 PERCENT.
MODERATE...30 TO 60 PERCENT.
HIGH...GREATER THAN 60 PERCENT.
OVERVIEW...HIGH CONFIDENCE THE DAY TOMORROW...LOWER CONFIDENCE IN
WED NIGHT.
GENERALLY VFR SAVE FOR SOME TERMINALS IN HIGHER TERRAIN /LIKE ORH/
WHICH MAY DIP TO BRIEF MVFR CIGS UNTIL THE STRATO-CU CLEARS OVER
THE NEXT FEW HOURS. WINDS ALSO GRADUALLY SUBSIDE OUT OF THE WNW
OVERNIGHT. BECOMING LIGHT /BELOW 10 KT/ PRETTY MUCH EVERYWHERE BY
12Z WED.
KBOS TAF...HIGH CONFIDENCE. VFR.
KBDL TAF...HIGH CONFIDENCE. VFR.
OUTLOOK...THURSDAY THROUGH SUNDAY...
THU THROUGH FRI...HIGH CONFIDENCE.
VFR AFTER ANY SNOW OVER S COASTAL TERMINALS MOVES OUT.
SAT...MODERATE CONFIDENCE.
COLD FRONTAL PASSAGE WITH SOME -SHSN AND POSSIBLE MVFR. MOSTLY
VFR HOWEVER.
SUN...MODERATE TO HIGH CONFIDENCE.
MOSTLY VFR.
&&
.MARINE...
HIGH FORECAST CONFIDENCE THROUGH WED NIGHT.
TONIGHT...
GUSTY WEST WINDS SLOWLY EASE. OTHERWISE DRY WEATHER WITH GOOD
VSBY.
WED...
WINDS DIMINISH AS HIGH PRES BUILDS OVER THE NE. VSBY REMAINS GOOD
ALONG WITH DRY WEATHER.
WED NIGHT...
SNOW OVERSPREADS THE SOUTHERN WATERS WITH VSBY 1-3 MILES. SNOW
TAPERS OFF NORTH OF CAPE COD BAY TO MA BAY. OCEAN LOW TRACKS SOUTH
OF 40N/70W...SO NE WINDS WILL REMAIN SUBGALE.
OUTLOOK...THURSDAY THROUGH SATURDAY...
THU INTO THU NIGHT...HIGH CONFIDENCE.
WINDS AND SEAS GRADUALLY DROP TO BELOW SMALL CRAFT ADVISORY
THRESHOLDS THROUGH THE DAY AND REMAIN BELOW OVERNIGHT.
FRI INTO SAT...MODERATE.
LOW PRES PASSES WELL N OF THE WATERS WITH A COLD FRONTAL PASSAGE
EXPECTED. MAY SEE BOTH WINDS AND SEAS REACH SMALL CRAFT ADVISORY
LEVELS BY FRI...CONTINUING THROUGH SAT.
SUN...MODERATE CONFIDENCE.
NW WINDS HAVE THE CHANCE OF APPROACHING GALE FORCE SUN.
OTHERWISE...SMALL CRAFT ADVISORIES ARE LIKELY TO CONTINUE.
&&
.BOX WATCHES/WARNINGS/ADVISORIES...
CT...NONE.
MA...NONE.
NH...NONE.
RI...NONE.
MARINE...SMALL CRAFT ADVISORY UNTIL 7 AM EST WEDNESDAY FOR ANZ231>235-
237-251.
SMALL CRAFT ADVISORY UNTIL 2 AM EST WEDNESDAY FOR ANZ230-236.
SMALL CRAFT ADVISORY UNTIL 1 PM EST WEDNESDAY FOR ANZ250-
254>256.
&&
$$
SYNOPSIS...NOCERA/DOODY
NEAR TERM...NOCERA/DOODY
SHORT TERM...NOCERA
LONG TERM...DOODY
AVIATION...NOCERA/DOODY
MARINE...NOCERA/DOODY
AREA FORECAST DISCUSSION
NWS TALLAHASSEE FL
354 PM EST Mon Feb 11 2013
.NEAR TERM [through Tonight]...
Thunderstorms continue as of 20 UTC along an outflow boundary that
stretched from Fitzgerald, GA (FZG) to Bainbridge, GA (BGE) to
Destin, FL (DTS). This outflow boundary has not moved much during
the course of the day, likely due to largely boundary-parallel
flow in the lowest 2km AGL. Meanwhile, GOES blended PWAT product
shows a broad ribbon of 1.2 to 1.5" values near and just behind
the slow-moving boundary - roughly 150-250% of normal across much
of the Gulf coast and into the Carolinas. These ingredients taken
together are favorable for flash flooding events due to training
thunderstorms. As such, it is not surprising that we have had some
flash flooding today - see the "Hydrology" section below for more
information.
The overall atmospheric pattern is not expected to change much
overnight. The outflow boundary / deep convergence zone should
shift gradually south into the evening hours, which should focus
the majority of the thunderstorm activity in our area from 22-06z
from around PAM-TVI. Meanwhile, a large area of moderate rain with
embedded thunderstorms was developing from C/S AL west into LA.
This area of rain was roughly on the broad nose of a newly
developed low-level moisture transport maximum - currently focused
into coastal Louisiana and Mississippi. The RAP projects that the
ribbon of strongest moisture transport should develop northeast
into our area by around 03z, with roughly similar PWAT values.
Therefore, we anticipate that rain - heavy at times, with embedded
storms - will redevelop across much of the NW half to two-thirds
of our area this evening.
Parts of our area remain in a "Slight Risk" of severe storms as of
the 20 UTC SPC SWODY1. An isolated severe storm cannot be ruled
out with some marginal mixed layer instability and effective shear
around 45 knots lingering into the evening.
&&
.SHORT TERM [Tuesday through Wednesday Night]...
A more pronounced mid-upper level trough - currently evident on
water vapor loops over the Desert Southwest - will dig ESE into
the Southern Plains on Tuesday, and then eject into the Ohio River
Valley on Tuesday Night. This evolution will allow for surface
cyclogenesis on Tuesday near coastal Louisiana, with the low
passing northwest of our area through central Alabama on Tuesday
Night. With stronger height falls and QG convergence to the west
of us on Tuesday, we should see a lull in the rain during the day.
The better chances of rain are expected to arrive from Tuesday
Night into Wednesday with the main trailing cold front. Portions
of our area are in a "Slight Risk" on the latest SPC SWODY2
outlook for the possibility of storms moving in later in the
period (Tuesday evening or overnight). The local confidence grids
and the SPC SREF calibrated severe probabilities both indicate
about a 15-20% chance of severe storms in the western two-thirds
of our area in the 12-hour period centered on 12z Wednesday. CIPS
analogs from SLU show about 5-10% probabilities, with about half
the analogs with at least one severe weather report in our area.
The combination of all of these probabilistic outlooks are in
fairly good agreement, and are consistent with some isolated
severe storms late Tuesday Night. Mean model MLCAPE on the ECMWF,
GFS, and CAM models looks to be around 500 j/kg overnight with
about 60-70 knots of deep layer shear.
&&
.LONG TERM [Thursday through Monday]...
Quieter weather arrives with surface high pressure and increasing
subsidence in the wake of the cold front on Thursday and Friday.
An amplifying longwave trough in the eastern CONUS on the weekend
may provide a shot of colder air, although details still vary from
model-to-model, and run-to-run.
&&
.AVIATION [through 18z Tuesday]...
Complex forecast for all TAF sites through the period with unsettled
weather ahead of a slow moving surface front. Scattered to numerous
showers and thunderstorms will be common around the area with MVFR
most prevalent. Occasional IFR conditions will accompany the
stronger storms through the evening, with MVFR and IFR prevailing
overnight due to cigs and vsby near or below airport minimums. A
repeat tomorrow, with perhaps more widespread showers and
thunderstorms late in the day.
&&
.MARINE...
Unsettled weather pattern will remain through mid week with a chance
of showers and thunderstorms, as well as breezy southerly winds each
period. Winds will increase a bit ahead of a cold front Tuesday
night and Wednesday, before switching to offshore on Thursday and
diminishing into the weekend.
&&
.FIRE WEATHER...
An unsettled weather pattern with scattered to numerous showers and
thunderstorms will continue at least through Wednesday. Drier
conditions will return late in the week but we see no fire weather
concerns at this time.
&&
.HYDROLOGY...
Significant rainfall has largely ended for this afternoon across
the region. Observed and radar estimated rainfall totals show
significant storm totals of 10 to 15 inches from Central Geneva
County eastward through much of Houston County. Lower values of 5
to 8 inches were observed further east into parts of Southwestern
Georgia in the last 24 hours. Given recent rains across Southeast
Alabama and Southwest Georgia, little additional rainfall will be
needed to cause flash flooding in these areas and a flash flood
watch remains in effect through Tuesday morning.
Higher end rainfall totals are expected once again on Tuesday
evening through Wednesday across the area. Given the uncertainty
with the exact placement of the heaviest rainfall with this next
system, will delay any flash flood watches on this package. However,
it is expected that additional flash flood watches will be needed
across the area Tuesday night into Wednesday.
Riverine flooding will become an increasing concern as local runoff
is routed downstream from creeks and streams in Southeast Alabama.
River gages north of a line from Enterprise Alabama to Abbeville
Alabama appear to have crested with routed flow from these sites
progressing down into the Choctawhatchee River system. Rises to near
or in excess of minor flood stage is anticipated along the
Choctawhatchee River from Geneva southward to Caryville into Friday
given the current water already in the system. Flooding may also
continue downriver toward Bruce but this would not occur until
Saturday under present conditions. Rises on the Chipola River to
minor flood stage can also be expected later this week as runoff
progresses downstream from Southern Alabama.
Additional riverine flooding, both in magnitude and coverage, will
largely depend on the next 36 to 48 hours worth of rainfall. With
soils already saturated in Southeast Alabama and a good portion of
Southern Georgia, little additional rainfall will be absorbed there
and will thus be converted into runoff, increasing river flood
potential. River systems in South Central Georgia and the Florida
Big Bend still have plenty of capacity and riverine flooding is not
anticipated in these areas with this system.
&&
.PRELIMINARY POINT TEMPS/POPS...
Tallahassee 59 71 62 70 44 / 70 50 80 80 20
Panama City 60 71 62 66 46 / 80 50 80 70 20
Dothan 54 64 58 64 40 / 80 80 90 70 20
Albany 53 65 58 66 40 / 80 70 90 80 20
Valdosta 56 71 60 71 44 / 60 50 80 80 30
Cross City 61 77 61 74 48 / 20 30 60 70 30
Apalachicola 62 70 64 68 48 / 60 40 70 80 30
&&
.TAE WATCHES/WARNINGS/ADVISORIES...
FL...FLASH FLOOD WATCH through 6 AM CST Tuesday for Central
Walton-Holmes-Inland Walton-Jackson-Washington.
GA...FLASH FLOOD WATCH through 7 AM EST Tuesday for Baker-Ben
Hill-Calhoun-Clay-Dougherty-Early-Irwin-Lee-Miller-Quitman-
Randolph-Seminole-Terrell-Tift-Turner-Worth.
AL...FLASH FLOOD WATCH through 6 AM CST Tuesday for Coffee-Dale-
Geneva-Henry-Houston.
GM...None.
&&
$$
DISCUSSION...Lamers
AVIATION...Evans
MARINE...Evans
FIRE WEATHER...Barry
HYDROLOGY...Godsey
AREA FORECAST DISCUSSION
NWS TALLAHASSEE FL
930 AM EST Mon Feb 11 2013
.MESOSCALE UPDATE [through this Afternoon]...
Numerous showers and thunderstorms continue to develop along a
composite outflow boundary from near the Alabama-Florida border ENE
towards Albany, GA (KABY). The outflow boundary roughly establishes
the southward extent of a shallow cold pool that developed due to
abundant overnight convection. The cold pool appears to be about
2000 feet deep examining the BMX 12z sounding. 13z SPC mesoanalysis
(objective RUC analysis) indicates an elongated area of deep
moisture convergence along the outflow boundary, with a maximum in
west-southwesterly low-level moisture transport centered right over
SE Alabama. These moisture transport vectors, and thus the LLJ are
close to being boundary-parallel, which from a pattern recognition
standpoint is a classic setup for flash flooding. Given recent
reports with rainfall totals as high as 8 inches in some of our SE
Alabama zones, and the likelihood of additional heavy rainfall
through the day, we are becoming increasingly concerned about a
significant flash flooding event in those areas.
One additional concern is whether or not training echoes will
develop south with time - more into the I-10 corridor of the Florida
Panhandle. The HRRR supports this idea by afternoon, and therefore
the next decision to be made with respect to the Flash Flood Watch
will be whether or not to expand it south.
Once a decision is made (prior to 1530z) regarding additional
expansion of the FFA, we will likely ratchet up the wording in both
the existing portion of the FFA (where flooding is already
occurring) as well as the HWO.
There will still be the potential for isolated severe thunderstorms,
as mesoanalysis shows around 1000 j/kg of MLCAPE with around 50
knots of effective shear. However, the best severe weather potential
would probably be in the warm sector away from the training storms
that are anchored near the outflow boundary.
&&
.NEAR TERM [Tonight]...
With front sagging towards N FL tonight and likely stalling, it
will be a wet night however there should be a lull in development of
storms as we will be in relatively more stable air. may be some fog
development ahead of boundary.
&&
.SHORT TERM [Tuesday Through Wednesday]...
The large scale long wave pattern commence with a trough over NE
states and adjacent Canada with axis down ern seaboard and another
trough over Central and srn plains with low developing over TX.
Upper high anchored over Srn Gulf of Mex. At surface, low Canadian
Maritimes with cold front SSW down extreme wrn Atlc remaining
quasi-stnry across fl portion of CWA and into nrn gulf of Mex as
it gets caught in the upper level SW flow ahead of upstream
trough. With several impulses moving rapidly thru SE region in
strong divergent WSW mid/upper flow downstream of upper
trough/low, the primary concern will be locally heavy rainfall
through the period.
During Tuesday, the Ern low will move across New England while
Plains low likely opens up into a wave late TUES night. At
surface, low forms in Srn Plains and then moves ENE along Nrn Gulf
to LA Tues eve then inland to Srn AL at night with cold front
lifting NWD back i-10 corridor then to GA/AL border. Initially this
translates to increasing overrunning/isentropic lift spreading ewd.
As low lifts further newd, front dragged back SEWD across our area.
As far as severe wx, best shot will be Tues night. The proximity of
the surface low and proximity of front and upper features will favor
a strongly sheared environment. Key factor is where front actually
sets up. As SPC noted limiting factor may be development of multiple
thunderstorm clusters which would retard nwd movement of MT airmass
so best chances for strong to severe convection will be near
Panhandle coast where dew points in the mid-upper 60s are forecast.
North of front, more elevated tstms would favor hail while south of
front with strong deep layer shear, more surface based storms with
super cells/damaging wind and even an isold tornado cant be
discounted. GFS and Nam both show 0-6 KM shear of near 70 kt over
SE AL and 60kt over Panhandle at 12z Wed. SPC has placed area in
5% severe prob for Tues night and suspect this will be raised before
Tues night.
On Wed morning, low across Central GA with cold front bisecting CWA.
Several shortwaves move across region to push front SEWD. pops
remain especially on high side to begin the day. Chance of
strong to isold severe storms remain especially in warm sector where
deep shear will battle limited buoyancy for control. By end of
period, low races newd, cold front dragged SEWD of CWA with drier
air beginning to enter NW third of CWA. Total STP rainfall amounts
through Wed could easily average 3 to 4 inches with isolated 5
inches totals especially Nrn tier counties so flooding concerns will
be closely monitored.
&&
.LONG TERM [Wednesday Night through Sunday]...
The long term forecast is now a little more uncertain due to the
slower progression of the upper level system seen in the 12z model
cycle. The 00z Euro was weighted heavier in today`s long term
forecast, so should the slower progression of the 12z GFS pan out,
unsettled weather could continue into Thursday before the Eastern
CONUS pattern amplifies enough to kick out the frontal boundary
that had been in place across the region. Model guidance, however,
is in reasonably good agreement, that with the amplification of
the pattern late in the period (Fri-Sun), that cooler than normal
weather will be returning to the region. The GFS is much more
amplified and colder indicating lows potentially in the low to mid
20s by Sunday morning. Both the 10/00z and 10/12z Euro are less
intense with the incoming cooler airmass, so weighted the forecast
in this direction, which still produces well below normal
temperatures by Sunday.
&&
.AVIATION...
[Through 12Z Tuesday] This forecast will be an unsettled one with
periods of showers and thunderstorms. These will be most frequent
across DHN and ABY, but gradually develop southeast to impact the
remaining terminals as a cold front approaches from the northwest.
MVFR conditions will prevail for the most part, with periods of
IFR early this morning and again overnight. South to southwest
winds will be gusty today at all of the terminals with gusts to
around 20 kt. Gusts is TS will be higher. Finally, incoming data
from the KTAE 12Z upper air sounding indicated 40-kt winds at
around 1500 ft and this was supported by the KTLH and KEVX WAD
wind profile data. We included a LLWS group at TLH and ECP
accordingly.
&&
.MARINE...
Based on latest buoys, Small craft advisory will be allowed to drop
across the western waters with this package Winds will remain below
headline criteria despite occasional storms until Wednesday when an
area of low pressure will move across the Gulf. Winds will increase
to near advisory levels at this time. Winds will shift to offshore
on Thursday and then diminish into the weekend.
&&
.FIRE WEATHER...
A cold front will settle south across the forecast area from
northwest to southeast today into tonight. This front will then
return inland as a warm front on Tuesday as a low pressure system
tracks from the north central Gulf of Mexico northeast across the
southeastern states. This low will finally drag a stronger cold
front across the region on Wednesday. Drier air will arrive behind
this front for later in the work week. However, temperatures will
also be much cooler which will keep relative humidities above
critical values.
&&
.HYDROLOGY...
Overnight, some of the flashier rivers across SE AL has shown
notable rises and need to be monitored in case a river flood product
is necessary later today. Expect 2 to 4 inches of rain across the
region starting through Wednesday with the heaviest totals
across Southern Alabama and Georgia. Isolated higher totals up to 5
inches are possible. Widespread flooding is not anticipated.
However, rises on rivers are anticipated with this rainfall,
particularly further to the north where the combination of local
runoff and routed upstream flows lead to a few locations reaching
minor flood stage later this week.
&&
.PRELIMINARY POINT TEMPS/POPS...
Tallahassee 77 57 66 58 69 / 70 60 60 80 80
Panama City 74 58 65 57 67 / 80 60 60 90 80
Dothan 73 53 62 55 61 /100 80 80 90 80
Albany 73 52 60 54 67 /100 80 80 90 80
Valdosta 78 54 63 55 69 / 70 60 50 80 70
Cross City 78 57 73 56 72 / 20 40 30 70 70
Apalachicola 72 60 66 60 67 / 60 50 50 80 80
&&
.TAE WATCHES/WARNINGS/ADVISORIES...
FL...None.
GA...FLASH FLOOD WATCH through Tuesday morning for Baker-Calhoun-
Clay-Dougherty-Early-Lee-Miller-Quitman-Randolph-Terrell.
AL...FLASH FLOOD WATCH through late tonight for Coffee-Dale-Geneva-
Henry-Houston.
GM...None.
&&
$$
MESOSCALE UPDATE...Lamers
NEAR TERM...Wool
SHORT TERM...Block
LONG TERM...Godsey
AVIATION...Wool
MARINE...Block
FIRE WEATHER...Wool
HYDROLOGY...Block
AREA FORECAST DISCUSSION...UPDATED
NWS TAMPA BAY RUSKIN FL
350 AM EST MON FEB 11 2013
.SYNOPSIS...
08Z WATER VAPOR AND H4 RAP ANALYSIS SHOWS A CHAOTIC UPPER LEVEL
PATTERN ACROSS THE MID-SECTION OF THE COUNTRY CONSISTING OF 2 CLOSED
UPPER LOW FEATURES. THE FIRST IS EJECTING EASTWARD ACROSS THE
UPPER MIDWEST AND GREAT LAKES WHILE THE SECOND IS FURTHER UPSTREAM
NEAR THE 4-CORNERS REGION. IN RESPONSE TO THE HEIGHT FALLS SEEN OVER
THE CENTRAL STATES...THE DOWNSTREAM RIDGE AS BEEN AMPLIFIED AND IS
NOW QUITE SHARP AS ITS AXIS BEGINS TO EXIT THE EASTERN SEABOARD. THE
FL PENINSULA RESIDES AT THE BASE OF THE EAST COAST RIDGE. THE
INFLUENCE OF THIS FEATURE ON OUR COLUMN WAS SAMPLED WELL BY THE
11/00Z KTBW SOUNDING WHICH SHOWED A DEFINED SUBSIDENCE INVERSION
AROUND 800MB.
AT THE SURFACE...STRONG HIGH PRESSURE HAS BEEN PUSHED OFF THE
ATLANTIC SEABOARD BY A COLD FRONT MOVING THROUGH THE
APPALACHIANS...BUT CONTINUES TO RIDGE TO THE SOUTHWEST ACROSS THE
LOCAL AREA AND EASTERN GULF. THIS PRESSURE PATTERN IS ALLOWING FOR A
LIGHT EAST TO SOUTHEAST FLOW AND A SLOW INCREASE IN LOW LEVEL
MOISTURE. REGIONAL RADARS SHOW PLENTY OF SHOWERS AND STORMS TO OUR
NORTHWEST TOWARD THE I-10 CORRIDOR. THIS ACTIVITY WILL NOT BE A
THREAT TO OUR ZONES AS SUPPORTING ENERGY QUICKLY EXITS LATER TODAY
AND THE FRONT NEVER REACHES THIS FAR SOUTH.
&&
.SHORT TERM (TODAY THROUGH WEDNESDAY)...
TODAY/TONIGHT...
UPPER RIDGE OVER THE EASTERN SEABOARD WILL QUICKLY BREAK DOWN AS A
STRONG UPPER LOW QUICKLY TRANSLATES EASTWARD THROUGH THE GREAT LAKES
TOWARD THE NORTHEAST/MID-ATLANTIC. LUCKILY FOR OUR FORECAST...SOME
RESIDUAL RIDGING WILL HOLD ON DOWN TOWARD THE FLORIDA PENINSULA...
AND THIS PATTERN OVER-TOP AN EAST-WEST ORIENTED SURFACE RIDGE WILL
KEEP OUR LOCAL WEATHER GENERALLY FAIR...DRY...AND WARM. AS MENTIONED
ABOVE...ANY SHOWER ACTIVITY SHOULD STAY TO OUR NORTH TODAY AND WILL
KEEP MENTION OUT OF THE FORECAST. EFFICIENT DIURNAL MIXING AND A
LOW LEVEL COLUMN FEATURING 850MB TEMPS BETWEEN 12-14C WILL ALLOW FOR
A QUICK DIURNAL RISE IN TEMPERATURES INTO THE UPPER 70S AND LOWER
80S. MAY SEE SOME ONSHORE COMPONENT DEVELOP ALONG THE IMMEDIATE
COAST DURING THE AFTERNOON WHICH WILL KEEP TEMPS DOWN A FEW DEGREES
FROM LOCATIONS FURTHER INLAND...BUT EVEN STILL A DECENT BEACH DAY IS
IN STORE. LOW TEMPERATURES TONIGHT WILL BOTTOM OUT ONLY IN THE UPPER
50S TO LOWER 60S FOR MOST SPOTS AND IN THE MIDDLE 60S ALONG THE
COAST FROM TAMPA BAY SOUTHWARD. THE INCREASING LOW LEVEL DEWPOINTS
WILL BEGIN TO APPROACH A CRITICAL POINT LATER TONIGHT OVER THE
COOLER SHELF WATERS...AND CONCERNED FOR THE POTENTIAL DEVELOPING OF
SOME ADVECTION SEA-FOG. MANY OF THE HIGHER RESOLUTION GUIDANCE
MEMBERS ARE AGGRESSIVE IN THIS SEA-FOG DEVELOPMENT FROM THE MANATEE
COUNTY COAST AND NORTHWARD...AND ADDED AREAS OF FOG TO THE GRIDS.
TUESDAY/TUESDAY NIGHT...
NEXT SHORTWAVE WILL BEGIN TO MOVE EASTWARD FROM THE SOUTHERN PLAINS
AND SUPPORT AND ORGANIZING AREA OF LOW PRESSURE NEAR THE LA/MS/AL
COAST BY LATE IN THE DAY. A WARM FRONTAL FEATURE WILL EXTEND
EASTWARD FROM THIS LOW ALONG THE I-10 CORRIDOR. THIS CONFIGURATION
WILL PLACE OUR REGION WITHIN THE WARM SECTOR AND REMOVED FROM ANY
DECENT UPGLIDE OVER THE FRONT. WITH THIS IN MIND...MAY SEE A FEW
SCATTERED SHOWERS AS FAR SOUTH AS LEVY COUNTY...BUT ANY ORGANIZED
CONVECTION WILL BE FURTHER NORTH INTO AL/GA. THE REMAINDER OF THE
AREA...WILL BE GENERALLY DRY (OUTSIDE OF AN ISOLATED INSTABILITY
SHOWER). IF THE SEA-FOG POTENTIAL DOES COME TO VERIFY...THEN WE
WOULD STILL BE DEALING WITH THESE VISIBILITY ISSUES DURING THE
MORNING HOURS...WITH DIURNAL MIXING SHRINKING THE MAIN VIS
RESTRICTION REGION BACK TO THE MARINE ZONES AND IMMEDIATE NATURE
COAST FOR THE SECOND HALF OF THE DAY. THE AREA OF LOW PRESSURE WILL
MOVE NORTHEAST ACROSS AL TUESDAY NIGHT WITH A TRAILING COLD FRONT
APPROACHING FROM THE WEST. TIMING OF THE FRONT AND SWATH OF LARGE
SCALE LIFT/QG FORCING LOOKS TO KEEP THE BEST SHOWER/STORM POTENTIAL
HELD OFF FOR THE PENINSULA UNTIL THE DAYLIGHT HOURS OF WEDNESDAY.
MAY VERY WELL BE DEALING WITH SEA-FOG EXPANDING ONCE AGAIN AFTER
SUNSET TUESDAY EVENING.
WEDNESDAY...STRONG SHORTWAVE PASSES TO OUR NORTH PUSHING A COLD
FRONT THROUGH THE AREA. THE SHORTWAVE PATH PROVIDES THE BEST SETUP
FOR LARGE SCALE LIFT OVER THE NORTHERN HALF OF THE AREA...WHICH IS
FAIRLY TYPICAL. HIGHEST RAIN CHANCES WILL EXIST FROM TAMPA BAY
NORTHWARD ACROSS THE NATURE COAST. A MORE BROKEN BAND OF SHOWERS AND
DECREASING RAIN CHANCES WILL EXIST FURTHER SOUTH LATE IN THE DAY
WHEN THE BEST KINEMATICS WILL BE SHIFTING AWAY AS THE LOW LEVEL
FRONTAL FOCUS ARRIVES.
&&
.LONG TERM (WEDNESDAY NIGHT THROUGH NEXT SUNDAY)...
MUCH OF THE EXTENDED FORECAST WILL BE PLAGUED BY RAIN CHANCES AS A
SERIES OF UPPER-LEVEL IMPULSES MAINTAIN A TROUGH OVER THE EASTERN
HALF OF THE NATION. GLOBAL MODELS ARE ACTUALLY IN QUITE GOOD
AGREEMENT CONSIDERING THE COMPLEXITY AND EVENTUAL EVOLUTION OF THE
UPPER-LEVEL PATTERN. THE TRICK WILL BE IN NAILING DOWN WHEN OUR BEST
RAIN CHANCES WILL BE.
LOW PRESSURE WILL BE PULLING AWAY FROM THE MID-ATLANTIC COAST
WEDNESDAY NIGHT. A TRAILING COLD FRONT WILL BE WORKING ITS WAY
SOUTHWARD ACROSS FLORIDA. THE ECMWF KEEPS AMPLE MOISTURE AND ENOUGH
LIFT BEHIND THE FRONT TO CONTINUE RAIN CHANCES OVERNIGHT. THE GFS
AND CANADIAN DRY US OUT A LITTLE...BUT ALSO SHOW A CHANCE OF SHOWERS
THROUGH AT LEAST THE FIRST HALF OF THE NIGHT. WILL CONTINUE LOW-END
CHANCE POPS FOR NOW.
ON THURSDAY...WEST TO SOUTHWEST FLOW OVER THE TOP OF OUR SHALLOW
COOL AIRMASS WILL LEAD TO PLENTY OF CLOUDS AND MOST LIKELY SOME
SHOWERS HERE AND THERE. USING A BLEND OF GUIDANCE YIELDS CHANCE POPS
ONCE AGAIN...WHICH IS HIGHER THAN THE DRIER GFS/MEX.
FRIDAY AND SATURDAY WILL BE TOUCH CALLS AS FAR AS RAIN POTENTIAL
GOES. CERTAINLY FRIDAY HAS A GOOD CHANCE OF BEING WET SO INCLUDED 40
TO 50 PERCENT RAIN CHANCES FOR MOST OF THE AREA. SATURDAYS WEATHER
WILL DEPEND ON THE TIMING AND DEPTH OF A RATHER IMPRESSIVE
UPPER-LEVEL TROUGH FORECAST TO DIG SOUTHWARD INTO THE GULF. THE GFS
IS WEAKER AND LESS AMPLIFIED WHICH RESULTS IN A SLOWER MOVING COLD
FRONT THAT TAKES ITS TIME CLEARING OUT THE MOISTURE. THE ECMWF AND
CANADIAN ARE DEEPER AND STRONGER...WITH THE FRONT CLEARING THE
FLORIDA PENINSULA DURING THE DAY SATURDAY. ALL THREE OF THESE MODELS
SHOW MUCH COLDER AIR POISED TO INVADE OUR REGION FROM THE NORTH. I
AM INITIALLY LEAVING SOME RAIN CHANCES IN FOR SATURDAY FOR ALL BUT
THE FAR NORTH...BUT IF THE GFS COMES ON BOARD WITH THE ECMWF...WE
MAY BE ABLE TO SALVAGE A GOOD PART OF THE DAY.
BY SUNDAY...ALL THE MODELS HAVE THE FRONT THROUGH THE AREA WITH COLD
HIGH PRESSURE SETTLING IN OVER THE NORTHERN GULF. EVEN UNDER BRIGHT
SUNSHINE ON SUNDAY...WE WOULD LIKELY STRUGGLE TO GET OUT OF THE 60S.
THE 00Z ECMWF ACTUALLY SUPPORTS TEMPERATURES HOLDING IN THE 50S ALL
DAY. I HAVE BASICALLY USED THE WARMER MEX NUMBERS FOR NOW...BUT I
HAVE A FEELING WE WILL NEED TO TREND COLDER WITH TIME.
IT IS WORTH NOTING THAT THERE IS THE POTENTIAL FOR FREEZING
TEMPERATURES FOR MUCH OF THE INTERIOR AND NORTHERN ZONES SUNDAY
NIGHT. WE WILL LOOK MORE AT THIS AS WE MOVE CLOSER TO THE EVENT.
&&
.AVIATION...
EXPECTING MAINLY VFR CONDITIONS THROUGH TODAY AND INTO THIS EVENING.
SOME PATCHY FOG COULD BRING MVFR VISIBILITIES TO PGD AND LAL THIS
MORNING. A MORE SIGNIFICANT FOG EVENT IS POSSIBLE AFTER 06Z TONIGHT
WITH THE MOST FAVORED LOCATIONS BEING FROM SRQ NORTHWARD TO TPA AND
PIE.
&&
.MARINE...
HIGH PRESSURE WILL CONTINUE TO RIDGE ACROSS THE FL PENINSULA AND
EASTERN GULF WATERS THROUGH THIS AFTERNOON AND THEN RETREAT EASTWARD
TONIGHT INTO TUESDAY IN RESPONSE TO THE DEVELOPMENT OF A WARM
FRONTAL FEATURE AND SURFACE LOW ALONG THE NORTHERN GULF COAST. THIS
LOW WILL DRIFT TO OUR NORTH DURING THE MIDWEEK PERIOD WITH A
TRAILING COLD FRONT SHIFTING ACROSS THE EASTERN GULF WEDNESDAY
AFTERNOON AND NIGHT. SOUTHEAST WINDS WILL APPROACH CAUTIONARY LEVELS
AWAY FROM SHORE THIS MORNING AND THEN DIMINISH BELOW HEADLINE
CRITERIA THIS AFTERNOON AND EVENING. WINDS WILL THEN ONCE AGAIN
INCREASE TO CAUTIONARY LEVELS TUESDAY NIGHT AND WEDNESDAY AHEAD OF
THE APPROACHING COLD FRONT. WINDS WILL SHIFT NORTH AND THEN QUICKLY
NORTHEAST ON THURSDAY IN THE WAKE OF THIS FRONT.
&&
.FIRE WEATHER...
NO FIRE WEATHER CONCERNS ARE EXPECTED THE NEXT SEVERAL DAYS AS
SOUTHEAST TO SOUTHERLY FLOW BRING A SLOW INCREASE IN LOW LEVEL
MOISTURE AND PREVENT CRITICAL LEVELS OF RELATIVE HUMIDITY. THE
INCREASE IN LOW LEVEL MOISTURE IS EXPECTED TO INCREASE THE POTENTIAL
FOR SEA FOG TO IMPACT LOCATIONS NEAR THE COAST...ESPECIALLY MANATEE
COUNTY NORTHWARD THROUGH THE NATURE COAST. THIS POTENTIAL FOR
LOCALLY DENSE FOG WILL BEGIN LATE TONIGHT.
&&
.PRELIMINARY POINT TEMPS/POPS...
TPA 79 64 79 67 / 10 10 10 20
FMY 84 62 83 66 / 10 10 10 10
GIF 82 62 82 63 / 10 10 10 20
SRQ 79 60 79 67 / 10 10 10 10
BKV 81 57 80 64 / 10 10 10 40
SPG 80 64 79 67 / 10 10 10 20
&&
.TBW WATCHES/WARNINGS/ADVISORIES...
FL...BEACH HAZARDS STATEMENT UNTIL 2 PM EST THIS AFTERNOON FOR
CHARLOTTE-LEE.
GULF WATERS...NONE.
&&
$$
SYNOPSIS/SHORT TERM/MARINE/FIRE WEATHER...MROCZKA
LONG TERM/AVIATION...JILLSON
AREA FORECAST DISCUSSION
NWS CHARLESTON SC
1000 PM EST TUE FEB 12 2013
.SYNOPSIS...
A STATIONARY FRONT OVER FAR SOUTH GEORGIA WILL LIFT NORTH INTO THE
AREA AS A WARM FRONT LATE TONIGHT...WHILE GULF LOW PRESSURE PASSES
TO THE WEST. A COLD FRONT WILL SWEEP THROUGH THE AREA LATE WEDNESDAY...
WITH HIGH PRESSURE EXPECTED TO BUILD ACROSS THE REGION THURSDAY INTO
EARLY SATURDAY. ANOTHER COLD FRONT WILL PUSH THROUGH THE AREA
SATURDAY...FOLLOWED BY STRONGER HIGH PRESSURE AND COOLER CONDITIONS
INTO EARLY NEXT WEEK.
&&
.NEAR TERM /UNTIL 6 AM WEDNESDAY MORNING/...
MID EVENING SURFACE ANALYSIS IS COMPLEX AS THE GULF COAST WARM FRONT
INTO FAR SOUTH GEORGIA SLOW TO MAKE A MOVE N AS YET. WIDESPREAD RAINS
WERE FALLING UNDER COOLER IR SATELLITE TOPS OVER MUCH OF GEORGIA AND
SOUTH CAROLINA. A MESOSCALE LOW PRES AREA WAS LOCATED NEAR A BATCH
OF ELEVATED CONVECTION IN SOUTH GEORGIA. WEAK PRES FALLS WERE ONGOING
E OF THIS LOW INTO SE GEORGIA AT 02Z. MODELS DOING A REASONABLE JOB
WITH RAIN DEPICTION BUT MAY STRUGGLE OVERNIGHT WITH THE DETAIL OF
THE WARM FRONTAL PROGRESSION GIVEN COMPLICATED SURFACE LAYERED
STABILITY PROFILES. TEMPS WERE IN THE MID 50S MOST AREAS AS NEAR
SATURATION EVIDENT ON SOUNDING PROFILES. OVERNIGHT...A FAIRLY UNSTABLE
MID LEVEL ENVIRONMENT WILL SPREAD OVER THE FORECAST REGION BUT GIVEN
THE CURRENT RADAR TRENDS AND A MORE BELIEVABLE RUC FORECAST...THE
POTENTIAL FOR SEVERE WEATHER OVERNIGHT DOES NOT APPEAR TOO IMPRESSIVE
DESPITE INCREASING SHEAR PROFILES. 01Z RUC SUGGESTS CONVECTION
INCREASING OVER SE GEORGIA NEAR THE WARM FRONT WHICH IS STILL ALONG
I-16 AT 12Z.
NOT TOO MANY FORECAST CHANGES THIS EVENING WITH CATEGORICAL POPS
OVERNIGHT AND ONLY SLOWLY WARMING TEMPS WHERE RAINS WERE STEADIER
AND HEAVIER. THE BEST CHANCE FOR TEMPS RISING INTO THE MID 60S OR
WARMER LATE SHOULD BE TO THE S OF I-16.
&&
.SHORT TERM /6 AM WEDNESDAY MORNING THROUGH FRIDAY/...
WEDNESDAY...A STRONG SHORTWAVE TROUGH CURRENTLY OVER THE SOUTHERN
PLAINS WILL STEADILY SHIFT EAST EARLY WEDNESDAY...BECOMING MORE
STRETCHED/SHEARED AS IT MOVES INTO THE TENNESSEE/LOWER MISSISSIPPI
VALLEYS BY MIDDAY. THIS UPPER LEVEL ENERGY WILL SUPPORT THE
DEVELOPMENT OF A SURFACE LOW LIFTING FROM THE GULF COAST STATES INTO
THE UPSTATE CAROLINAS AS THE DAY PROGRESSES. NUMERICAL MODELS ARE IN
DECENT AGREEMENT THAT THE ASSOCIATED WARM FRONT WILL BE LOCATED
RIGHT ALONG THE NORTHERN BORDER OF THE FORECAST AREA...PERHAPS
AROUND THE SANTEE RIVER...BY DAYBREAK WEDNESDAY. AS A
RESULT...TEMPERATURES WILL RISE WELL ABOVE SEASONAL NORMALS INTO THE
UPPER 60S NORTH TO LOWER 70S SOUTH.
BOTH 12Z NAM AND 12Z GFS SOLUTIONS INDICATE LOW TO MODERATE
INSTABILITY INCREASING ACROSS MUCH OF THE FORECAST AREA THROUGH
THE MORNING AND AFTERNOON HOURS...WITH CAPE VALUES POSSIBLY
REACHING 1000 J/KG OVER THE CHARLESTON TRI COUNTY REGION BY 18Z.
THE SOUTHEAST STATES WILL BE IN THE VICINITY OF THE RIGHT REAR
OF A 100 KT 500 MB JET AND A 30 TO 40 KT LOW LEVEL JET. THE
COMBINATION OF MODERATELY FAVORABLE INSTABILITY AND DECENT SHEAR
SUGGESTS ISOLATED TO SCATTERED THUNDERSTORMS ARE POSSIBLE...WITH
A FEW THUNDERSTORMS POTENTIALLY BECOMING STRONG AND ORGANIZED.
STORM PREDICTION CENTER HAS PLACED THE SOUTHERN HALF OF THE
FORECAST AREA...WHERE TEMPERATURES AND DEWPOINTS WILL BE
HIGHEST...WITHIN A SLIGHT RISK FOR SEVERE THUNDERSTORM
DEVELOPMENT. WILL ADD MENTION OF ISOLATED STORMS POSSIBLY
BECOMING SEVERE IN THE HAZARDOUS WEATHER OUTLOOK. IT SHOULD BE
NOTED THAT THICK CLOUD COVER AND MARGINAL LAPSE RATES COULD
NEGATIVELY IMPACT STORM ORGANIZATION...AND MUCH UNCERTAINTY IN
THUNDERSTORM STRENGTH AND COVERAGE REMAINS.
WEDNESDAY NIGHT...AS THE SURFACE LOW CONTINUES TO LIFT
NORTH/NORTHEAST TOWARD THE MID ATLANTIC COASTLINE...A TRAILING
COLD FRONT WILL PULL THROUGH THE FORECAST AREA BY THE EVENING
HOURS. SHOWER AND THUNDERSTORM CHANCES WILL THUS END FAIRLY
QUICKLY FROM WEST TO EAST BETWEEN 00Z AND 06Z WEDNESDAY
NIGHT...WITH DRIER DEEP LAYER AIR MOVING IN BEHIND THE DEPARTING
FRONT. COLD ADVECTION OVERNIGHT WILL ALLOW TEMPERATURES TO FALL
INTO THE UPPER 30S INLAND TO THE LOWER 40S NEAR THE COAST.
THURSDAY AND FRIDAY...WEAK SURFACE HIGH PRESSURE WILL BUILD INTO THE
REGION AND SET UP PREVAILING WEST/NORTHWEST SYNOPTIC FLOW. EXPECT
DRY CONDITIONS AND SLIGHTLY COOLER TEMPERATURES...WITH HIGHS
GENERALLY REACHING THE MID 60S THURSDAY AND THE MID TO UPPER 60S
FRIDAY. LOW TEMPERATURES THURSDAY NIGHT WILL REFLECT IMPROVED
RADIATIONAL COOLING CONDITIONS UNDER CLEAR SKIES AND LIGHTER
WINDS...RANGING FROM THE MID TO UPPER 30S INLAND TO THE LOWER 40S
NEAR THE COAST.
&&
.LONG TERM /FRIDAY NIGHT THROUGH TUESDAY/...
AN ARCTIC FRONT WILL PUSH THROUGH THE SOUTHEAST STATES LATE
SATURDAY AHEAD OF A SHARP UPPER TROUGH DIVING TOWARD THE AREA FROM
THE GREAT LAKES/CENTRAL PLAINS REGION. THERE IS SOME EVIDENCE IN
MEDIUM RANGE MODEL SOLUTIONS OF ISOLATED RAIN ASSOCIATED WITH THE
UPPER TROUGH PROGRESSION TO SUPPORT SLIGHT CHANCE POPS FOR THE
NORTHERN HALF OF THE AREA SATURDAY NIGHT. GUIDANCE IS STILL
SHOWING HIGHS IN THE UPPER 50S TO LOWER 60S AHEAD OF THE FRONT ON
SATURDAY...BUT SUSPECT TEMPERATURES WILL BE FALLING DURING THE
AFTERNOON DEPENDING ON THE EXACT TIMING OF THE FRONT. THERE IS
SOME CONCERN ABOUT THE POTENTIAL FOR SOME BRIEF WINTRY PRECIP
WITH THIS FRONT...AS MODELS DROP 850MB TEMPS TO -2 TO -4C BY 00Z
SUNDAY. HOWEVER...BOUNDARY LATER TEMPS COULD BE TOO WARM. PREFER
TO CONTINUE MONITORING MODEL TRENDS FOR THIS PERIOD.
THE DEEP ARCTIC UPPER TROUGH PUSHES OFFSHORE INTO THE ATLANTIC
SUNDAY...THEN ZONAL FLOW TO SLIGHT RIDGING BUILDS BACK INTO THE
UPPER LEVELS FOR MONDAY. BELOW CLIMO TEMPS EXPECTED FOR SUNDAY AND
MONDAY WITH HIGHS IN THE 50S...AS WELL AS THE POTENTIAL FOR
FREEZING OVERNIGHT/EARLY MORNING TEMPS...ESPECIALLY MONDAY
MORNING. EXPECT MODERATING TEMPS BY TUESDAY AS MODELS SHOW
ANOTHER STRONG UPPER TROUGH AND ASSOCIATED SURFACE FRONT MOVING
TOWARD THE REGION. DUE TO UNCERTAINTY IN THE TIMING OF THIS
FEATURE...HAVE GONE WITH SLIGHT CHANCE TO CHANCE POPS.
&&
.AVIATION /02Z WEDNESDAY THROUGH SUNDAY/...
OVERNIGHT...MODELS SUGGEST HIGHEST CERTAINTIES OF PROLONGED RAINS
AT KCHS WITH PERIODS OF RAIN AT KSAV OVERNIGHT AT KSAV. KSAV
SHOULD MAINTAIN A BLANKET OF STRATUS/STRATOFRACTUS OVERNIGHT
THUS A CONTINUATION OF IFR/LIFR CIGS. AT KCHS WHERE THE RAIN GOT
OFF TO A LATER START...WE THINK CONDITIONS WILL DETERIORATE TO
IFR OR LOWER DURING THE EVENING AND PERSIST OVERNIGHT. WE HAVE
INTRODUCED LLWS AT BOTH AIRPORTS AS A STRONG AND VEERING 40-50 KT
LOW LEVEL JET DEVELOPS THROUGH THE COASTAL CORRIDOR.
ON THU...BOTH TERMINALS WILL SEE WINDS BECOMING SW AND EVENTUALLY
W LATE AS A FRONT MOVES TO THE COAST. IFR OR LOWER CONDITIONS SHOULD
BECOME MVFR AND PROBABLY VFR BY LATE AFTERNOON AS OFFSHORE FLOW
COMMENCES. TIMING OF CONVECTIVE RAINS GETS QUITE TRICKY AS MODEL
DISCREPANCIES CAN INTO THE PICTURE. IT APPEARS LIKELIHOODS FOR
RAIN QUICKLY BEGIN TO DIMINISH AFTER MID AFTERNOON.
EXTENDED AVIATION OUTLOOK...MAINLY VFR THROUGH THE WEEKEND.
&&
.MARINE...
RELATIVELY WEAK WINDS/SEAS THIS EVENING WILL GIVE WAY TO SOUTHERLY
FLOW OVERNIGHT FROM SOUTH TO NORTH AS A WARM FRONT LIFTS NORTH AND
A LOW-LEVEL JET DEVELOPS. SOME GUSTS TO 25 KT WILL BECOME POSSIBLE
AFTER MIDNIGHT ACROSS THE OFFSHORE GA WATERS. ELSEWHERE IT WILL BE
CLOSER TO DAYBREAK WEDNESDAY WHEN THE WINDS BECOME MORE GUSTY. WE
HAVE THE SMALL CRAFT ADVISORY FOR OFFSHORE GA WATERS TONIGHT.
WEDNESDAY THROUGH SUNDAY...SMALL CRAFT ADVISORY CONDITIONS WILL
BE ONGOING FOR MUCH OF THE MARINE AREA WEDNESDAY...AS A SURFACE
LOW PASSES WELL NORTHWEST OF THE WATERS AND A COLD FRONT CROSSES
OFFSHORE DURING THE EVENING HOURS. EXPECT WINDS AND SEAS TO
GRADUALLY FALL BELOW ADVISORY LEVELS LATE WEDNESDAY NIGHT INTO
THURSDAY MORNING...WITH HIGH PRESSURE BUILDING OVER THE REGION
FROM THE WEST. A STRONGER COLD FRONT AND HIGH PRESSURE IS EXPECTED
TO SUPPORT ANOTHER SURGE IN WINDS TO ADVISORY LEVELS LATER
SATURDAY AND SATURDAY NIGHT. THERE IS EVEN THE POTENTIAL FOR SOME
MARGINAL GALE CONDITIONS SATURDAY NIGHT...HOWEVER UNCERTAINTY IS TOO
HIGH TO MENTION AT THIS POINT. WINDS AND SEAS WILL BE GRADUALLY
FALLING BACK BELOW HIGHLIGHTS SUNDAY...AS HIGH PRESSURE BUILDS
OVER THE REGION AGAIN.
&&
.HYDROLOGY...
PERIODS OF DROUGHT-RELIEVING RAINS TO CONTINUE THROUGH WEDNESDAY.
STORM TOTAL RAINFALL AMOUNTS OF 2-4 INCHES WILL BE SPREAD OVER A
LONG ENOUGH PERIOD TO PRECLUDE WIDESPREAD FLASH FLOOD ISSUES...
BUT SEVERAL OF OUR RIVERS ARE EXPECTED TO APPROACH FLOOD STAGE
LATER IN THE WEEK.
&&
.CHS WATCHES/WARNINGS/ADVISORIES...
GA...NONE.
SC...NONE.
MARINE...SMALL CRAFT ADVISORY FROM 6 AM TO 10 PM EST WEDNESDAY FOR
AMZ352.
SMALL CRAFT ADVISORY UNTIL 5 AM EST THURSDAY FOR AMZ374.
SMALL CRAFT ADVISORY FROM 6 AM WEDNESDAY TO 5 AM EST THURSDAY
FOR AMZ350.
&&
$$
SYNOPSIS...
NEAR TERM...
SHORT TERM...79
LONG TERM...RFM
AVIATION...
MARINE...JRL/RFM
HYDROLOGY...
AREA FORECAST DISCUSSION
NWS NORTHERN INDIANA
635 PM EST TUE FEB 12 2013
.AVIATION...
MVFR CIGS WILL POSE A SMALL PROBLEM THIS EVENING WITH RESPECT TO
MIXING AND EROSION. HIRES MODEL GUIDANCE VARIES WITH LOW LEVEL
MOISTURE WHICH REMAINS TRAPPED UNDER STRONG SUBSIDENCE INVERSION.
HAVE SEEN INDICATIONS OF BREAKS IN LAST FEW HOURS AND SFC OBS
SHOWING SOME EROSION WITH SOUTHERN FLANK SOUTH OF TAF SITES. WILL
REMAIN OPTIMISTIC FOR A FEW MORE HOURS IN GRADUALLY CLEARING THE
CIGS BUT THIS MAY NEED TO BE DELAYED FURTHER IF TREND CHANGES WITH
LOSS OF SUN AND MIXING. SHOULD SEE THE CLOUDS EVENTUALLY ADVECT OUT
AS NEXT WEAK SHORT WAVE APPROACHES ON WEDNESDAY. WINDS WILL BECOME
LIGHT AND VARIABLE OVERNIGHT AND REMAIN AT OR UNDER 10 KNOTS ON
WEDNESDAY.
&&
.SHORT TERM...
SFC RIDGING INVOF OF OH RVR WILL BREAK DOWN INADV OF SW CLIPPER
DROPPING OUT OF SWRN CANADA WED AFTN. HWVR NO SENSIBLE WX OF
CONSEQUENCE XPCD WITHIN THIS EVOLUTION THROUGH THIS PD.
MIXING/EROSION OF SC CLD DECK ONGOING THIS AFTN W/PARTIAL SUNSHINE
NOW ACRS MUCH OF ERN HALF CWA BUT WRN FLANK EXTENDING BACK INTO NE
IL HOLDING TOUGH AND MAY POSE A BUST OVERNIGHT WRT MIN TEMPS. ATTM
SHRT TERM RUC GIVES A NOD TWD PRIOR EVEN MOS BLEND. OTRWS AT LEAST
PARTIAL INSOLATION XPCD AGAIN ON WED W/STGR DIURNAL WITHIN MODEST LL
SWRLY FLW. IN FACT MOS MAX TEMP SPLIT ESSENTIALLY EVEN AND REFLECTED
IN GRIDDED MAXS.
&&
.LONG TERM... /THURSDAY THROUGH TUESDAY/
ACTIVE PATTERN IN STORE FOR THE LONG TERM PERIOD. ONE MORE DAY OF
ABOVE NORMAL TEMPS ON TAP FOR THURSDAY AHEAD OF SHOT OF ARCTIC AIR
DROPPING SE ACROSS THE PLAINS. STRONG FORCING ALONG THE FRONT WILL
STIR UP AT LEAST A CHC FOR RAIN OR SNOW SHOWERS BUT OVERALL QPF
APPEARS MINIMAL AT THIS POINT. POPS STILL HELD IN CHC/SCHC RANGE
FOR NOW.
GREATER FOCUS THEN TURNS TOWARDS LAKE EFFECT POTENTIAL AS STG NW
FLOW SETS UP WITH SFC-850 MB DELTA T`S PUSHING 20 C AND SFC-700 MB
DELTA T`S PUSHING UPR 20S. NAM/WRF SHOW A PERIOD OF FAVORABLE
COLLOCATION OF DGZ AND TOP OF STRONG OMEGA. INVERSION HGTS BEGIN TO
CLIMB...ESPECIALLY DURING THE DAY FRIDAY WHEN SOME ADDITIONAL
SYNOPTIC MSTR ARRIVES AND A REINFORCING SHOT OF COLD AIR. HAVE
TENDED TO FOCUS GREATEST POPS FRIDAY TO MATCH WITH THE ABOVE SETUP.
ACCUMS AT THIS POINT APPEAR TO BE ON THE LIGHTER SIDE BUT WILL NEED
TO BE WATCHED IN COMING FORECASTS. WHILE AN OUTLIER...SEVERAL RUNS
OF THE GEM NHEM MODEL HAVE BEEN SHOWING PHASING OF N/S STREAM
SYSTEMS SOONER THAN LATER WITH A STORM AFFECTING THE GREAT LAKES VS
EAST COAST. ECMWF/GFS DO NOT PHASES THE ENERGY UNTIL REACHING EAST
COAST SO AT THIS POINT HAVE TO PUT IT ON THE BACK BURNER BUT WILL
NEED TO WATCH.
LAKE EFFECT WILL LINGER POTENTIALLY THROUGH MUCH OF THE WEEKEND WITH
CONTINUED NW FLOW AND 850 MB RIDGING STILL TO THE WEST UNTIL LATE
SUNDAY. NEXT SYSTEM TO FOCUS ON WILL BE WHAT LOOKS LIKE A PANHANDLE
HOOK COMING TOWARDS THE REGION MONDAY NIGHT INTO TUESDAY. SIGNALS
POINT TOWARDS MEASURABLE PRECIP FOR PARTS OF THE AREA BUT EXACT
TRACK AND AMOUNT OF COLD AIR REMAIN QUESTIONABLE THIS FAR OUT IN THE
FORECAST. HAVE WENT WITH MID-HIGH END CHC POPS WITH MIX OF RAIN OR
SNOW WITH LIKELY REFINEMENT OF FORECAST TO COME OVER THE NEXT
SEVERAL DAYS.
&&
.IWX WATCHES/WARNINGS/ADVISORIES...
IN...NONE.
MI...NONE.
OH...NONE.
LM...NONE.
&&
$$
SHORT TERM...T
LONG TERM...FISHER
AVIATION...LASHLEY
AREA FORECAST DISCUSSION
NWS INDIANAPOLIS IN
1131 PM EST SUN FEB 10 2013
.UPDATE...
THE AVIATION SECTION HAS BEEN UPDATED BELOW.
&&
.SYNOPSIS...
ISSUED AT 215 PM EST SUN FEB 10 2013
A STRONG OCCLUDED SYSTEM WILL LIFT NORTHEAST ACROSS CENTRAL INDIANA
LATE TONIGHT WITH THE RAIN EXPECTED TO END IN ITS WAKE. THEN...HIGH
PRESSURE WILL BUILD IN FROM THE PLAINS AND SOUTHERN STATES THROUGH
TUESDAY ALLOWING FOR DRY WEATHER AND TEMPERATURES CLOSER TO
SEASONABLE. A SOUTHERN SYSTEM WILL BRING A CHANCE OF RAIN OR SNOW TO
FAR SOUTH CENTRAL INDIANA TUESDAY NIGHT AND WEDNESDAY. THE NEXT
CHANCE OF PRECIPITATION AFTER THAT WILL BE THURSDAY NIGHT THROUGH
SATURDAY WITH RAIN OR SNOW POSSIBLE AS A LOW PRESSURE SYSTEM PIVOTS
ACROSS THE LOWER GREAT LAKES. ABOVE NORMAL TEMPERATURES ON THURSDAY
AHEAD OF THE SYSTEM WILL GIVE WAY TO BELOW NORMAL TEMPERATURES LATE
IN THE WEEKEND BEHIND AN ASSOCIATED COLD FRONT.
&&
.NEAR TERM /REST OF TONIGHT/...
ISSUED AT 719 PM EST SUN FEB 10 2013
LOWERED POPS TO LOW CHANCE/SLIGHT CHANCE ACROSS THE AREA BASED ON
RADAR MOSAIC AND HRRR FIELDS FOR THE NEXT SEVERAL HOURS. SOUNDINGS
ARE LOOKING MORE LIKE SPRINKLES/DRIZZLE POSSIBLE FOR THE NEXT FEW
HOURS AND THEN DRY WITH CLEARING SKIES AS A DRY SLOT CURRENTLY OVER
MISSOURI/WESTERN ILLINOIS MOVES THROUGH THE AREA. WIND GUSTS COULD
INCREASE A BIT WITH THE ARRIVAL OF THE DRY SLOT AND COULD MAX OUT
AROUND 40 MPH. GOING LOWS IN THE MIDDLE 30S TO AROUND 40 SEEM A
LITTLE COOL BUT STILL COULD SEE A GOOD DROP WITH CLOUDS BREAKING
FROM THE DRY SLOT SO WILL LEAVE ALONE FOR NOW.
&&
.SHORT TERM /MONDAY THROUGH WEDNESDAY/...
ISSUED AT 215 PM EST SUN FEB 10 2013
MAIN CHALLENGE TO THE FORECAST WILL BE WINDS AND CLOUD COVER MONDAY
ALONG WITH RESULTANT TEMPERATURES. ANOTHER MAIN ISSUE IS WHETHER TO
BRING ANY POPS IN TUESDAY NIGHT AND WEDNESDAY AND IF SO HOW FAR
NORTH TO BRING THEM AS AS MODELS ARE ALL OVER THE PLACE ON A WEAK
SOUTHERN SURFACE SYSTEM WITH THE 12Z NAM BRINGING THIS SYSTEM AS FAR
NORTH AS NORTHERN KENTUCKY BY 00Z THURSDAY WITH QPF ACROSS ALL OF
THE FORECAST AREA WEDNESDAY. AND AT THE OTHER SPECTRUM THE
GEM...ECMWF AND GFS HAVE IT WELL SOUTH NEAR THE GULF WITH QPF ONLY
ACROSS OUR FAR SOUTH MAINLY WEDNESDAY. THE NAM IS AN OUTLIER WITH A
SLOWER AND MUCH STRONGER UPPER SYSTEM AS IT CLOSES INTO AN UPPER LOW
AND MOVES INTO SOUTHWESTERN INDIANA BY 00Z THURSDAY WHICH IS THE
MAIN REASON FOR ITS FURTHER NORTH SURFACE LOW TRACK AND RESULT QPF.
PER HPC HEMISPHERIC DISCUSSION THE NAM SOLUTION REGARDING A STRONGER
LOW IS PLAUSIBLE BUT WITH ALL THE OTHER MODELS KEEPING THE SURFACE
LOW WELL SOUTH...FAVOR THAT SOLUTION AND ALSO FAVOR A SLOWER
SOLUTION PER MODEL TRENDS THAT WOULD FAVOR HOLDING OFF ON POPS UNTIL
AFTER 06Z WEDNESDAY SOUTH CENTRAL AND CONTINUING THROUGH THE DAY
WEDNESDAY. SMALL POPS ALSO LOOK LIKE THE WAY TO GO FOR NOW
ESPECIALLY WITH THE UNCERTAINTY OF TIMING AND STRENGTH OF THE
SYSTEM.
GETTING BACK TO MONDAY...PLENTY OF LOW LEVEL MOISTURE IS PROGGED TO
LINGER AS THE OCCLUDED LOW CENTER MOVES EAST ACROSS SOUTHERN
ONTARIO. IN ADDITION...STRONG COLD AIR ADVECTION WILL BE TAKING
PLACE. THUS...THINK THERE WILL BE A GOOD DEGREE OF CLOUD COVER
AROUND AND FAVOR ADDING MORE CLOUD COVER THAN ALLBLEND AND KEEPING
TEMPERATURES AT OR BELOW SIMILAR MOS. BUFKIT SUGGESTS WINDS TO 30
KNOTS AND GUSTS TO OVER 35 KNOTS POSSIBLE. SO...IT IS LOOKING LIKE
NEAR ADVISORY CRITERIA. WILL COORDINATE AND MAKE LAST MINUTE
DECISION ON WHETHER TO ISSUE AN ADVISORY OR A SPECIAL WEATHER
STATEMENT.
MONDAY NIGHT...SURFACE HIGH PRESSURE WILL BUILD IN FROM THE PLAINS
AND SOUTHERN STATES...BUT MODEL TIME SECTIONS AND SOUNDINGS STILL
HOLD ON TO A DECENT AMOUNT OF LOW LEVEL MOISTURE. SO...NOT EXPECTING
FULL CLEARING...BUT SHOULD SEE SOME BREAKS. MOS TEMPERATURES VERY
CLOSE...SO WILL STICK CLOSE TO THEM. FINALLY...TUESDAY...THE LOW
LEVELS DRY UP WITH ONLY SOME HIGH CLOUDS AHEAD OF THE AFOREMENTIONED
UPPER SYSTEM EXPECTED. WILL LEAN TOWARDS THE SLIGHTLY WARMER 12Z GFS
MOS DUE TO THE LACK OF LOW CLOUDS.
&&
.LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY/...
ISSUED AT 244 PM EST SUN FEB 10 2013
THERE IS SIGNIFICANT VARIABILITY IN EXTENDED PERIOD AS SEVERAL
LITTLE DISTURBANCES ROTATE AROUND A VERY BROAD UPPER LEVEL LOW.
SO...WILL NOT DEVIATE MUCH FROM LATEST INITIALIZATION NUMBERS.
THERE WILL BE PERIODIC CHANCES FOR PRECIP FROM THURSDAY NIGHT
THROUGH SUNDAY...BUT PRECIP WILL FLUCTUATE BETWEEN RAIN/WINTRY
MIX/SNOW UNTIL COLDER AIR SETTLES IN NEXT WEEKEND. WILL STICK WITH
ALLBLEND IN REGARD TO TEMPS AND NOT DEVIATE.
&&
.AVIATION /DISCUSSION FOR 110600Z TAF ISSUANCE/...
ISSUED AT 1131 PM EST SUN FEB 10 2013
MVFR CEILINGS WILL IMPACT PRIMARILY KIND AND KBMG FOR THE FIRST
COUPLE HOURS OF THE FORECAST...FOLLOWED BY VFR CONDITIONS. MVFR
CEILINGS MAY REDEVELOP BY LATE MORNING AT KLAF. STRONG WIND GUSTS
WILL IMPACT ALL TERMINALS THROUGH THE FORECAST PERIOD.
CLEARING AREA ASSOCIATED WITH THE DRY SLOT MAKING STEADY EASTWARD
PROGRESS AND SHOULD BE EAST OF BOTH KHUF AND KLAF BY 06Z. HAVE
HELD ONTO MVFR CEILINGS AT KBMG AND KIND FOR A COUPLE HOURS BUT
EXPECT SKIES CLEARING AT THESE SITES AS WELL BY 08Z. MAINLY CLEAR
SKIES ARE THEN EXPECTED FOR MUCH OF THE REGION FOR THE REST OF THE
OVERNIGHT WITH SOUTHWEST WIND GUSTS STEADILY INCREASING TO NEAR
30KTS BY DAYBREAK. STRATUS ASSOCIATED WITH THE COLD POOL WILL WORK
BACK INTO KLAF TOWARDS DAYBREAK...GRADUALLY EXPANDING SOUTHEAST TO
ENCOMPASS THE OTHER TERMINALS THROUGH LATE MORNING. MVFR CEILINGS
ARE POSSIBLE AT KLAF BUT OTHERWISE EXPECT CLOUD HEIGHTS TO SETTLE
BETWEEN 3-4KFT FOR THE AFTERNOON.
WINDS WILL BE A SIGNIFICANT FACTOR ON AVIATORS MONDAY AS TIGHT
PRESSURE GRADIENT AND STRONG WINDS ALOFT PERSIST AS DEEP LOW
PRESSURE MOVES EAST ACROSS THE GREAT LAKES. PREDOMINANT WIND
DIRECTION FOR THE AFTERNOON WILL BE 250-260 DEGREES WITH
SUSTAINEDS AT 25 TO 30KTS AND GUSTS APPROACHING 40KTS. WINDS WILL
BEGIN TO RELAX MONDAY EVENING AS HIGH PRESSURE BUILDS ACROSS THE
REGION WITH SKIES SLOWLY CLEARING FROM THE SOUTHWEST.
&&
.IND WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
SYNOPSIS...MK
NEAR TERM...CP
SHORT TERM...MK
LONG TERM....TDUD
AVIATION...RYAN
AREA FORECAST DISCUSSION
NWS DES MOINES IA
1146 AM CST MON FEB 11 2013
.SHORT TERM /TODAY/...
MAIN FORECAST CONCERN TODAY IS WITH
WINDS...AND LIGHT SNOW SHOWERS/FZDZ ACROSS NORTHERN IOWA. VERTICALLY
STACKED LOW WILL CONTINUE TO PUSH EASTWARD THROUGH THE DAY AND
PRESSURE GRADIENT BEGINS TO RELAX DURING THE AFTERNOON HOURS.
NAM/GFS BUFR SOUNDINGS SUGGEST SOME LIGHT SNOW SHOWERS OR FLURRIES
OVER NORTHERN IOWA THROUGH 18Z BUT RAP SHOWING LOSS OF ICE
INTRODUCTION IN THE COLUMN PERIODICALLY DURING THE MORNING. SEVERAL
CURRENT OBSERVATIONS ACROSS NORTHERN IOWA REPORTING DZ/UP SUGGESTING
THIS IS ALREADY OCCURRING. FORCING REMAINS WEAK BUT LOOKS TO BE
ENOUGH TO WARRANT THE MENTION OF PATCHY FZDZ ACROSS THE NORTHEAST
THROUGH 18Z.
WENT CLOSE TO GUIDANCE TODAY FOR MAX TEMPERATURES AS MODELS ARE IN
GOOD AGREEMENT AND FELT NO REASON TO DEVIATE MUCH FROM THEM. THIS
RESULTED IN TWEAKING TEMPS UP SLIGHTLY ACROSS THE SOUTH. NOT
EXPECTING STRATUS TO CLEAR OUT ACROSS THE SOUTHWEST UNTIL AFTER 21Z
WHEN THE PRESSURE GRADIENT BEGINS TO WEAKEN. KEPT OVERCAST OVER THE
NORTH TO EAST THROUGH 00Z TUESDAY AS LOW LEVEL MOISTURE REMAINS
PERSISTENT WITHIN THE CAA.
.LONG TERM /TONIGHT THROUGH SUNDAY/...
THE UPPER LOW PRESSURE WILL CONTINUE TO RACE OFF TO THE EAST
TONIGHT AND BE NEAR MAIN BY 12Z TUESDAY MORNING. THIS WILL ALLOW
MUCH DRIER AIR TO FILTER INTO THE STATE AS BROAD AREA OF HIGH
PRESSURE SHIFTS EAST INTO THE MIDWEST. GENERAL TRENDS FOR TUESDAY
AND WEDNESDAY ARE WARMER. THE DRY AIR WILL WARM NICELY ON TUESDAY
UNDER SOUTHWEST FLOW. THE FLOW WILL BECOME MORE DOWN SLOPE ORIENTED
TUESDAY NIGHT INTO WEDNESDAY AHEAD A VIGOROUS UPPER WAVE THAT WILL
ARRIVE ALONG WITH AN ASSOCIATED COLD FRONT WEDNESDAY NIGHT.
TEMPERATURES ON WEDNESDAY WILL BE IN THE MID TO UPPER 40S OVER THE
CENTRAL AND SOUTH AND A FEW LOCATIONS MAY HIT 50 IF ENOUGH SUN IS
AVAILABLE.
THE UPPER WAVE WILL PASS THROUGH WEDNESDAY NIGHT INTO THURSDAY.
GUSTY NORTHWEST WINDS WILL KEEP COLD ADVECTION IN PLACE THROUGH
THE DAY THURSDAY AND MAY HAVE SLOWLY FALLING TEMPERATURES DURING
THE AFTERNOON. THE AIR MASS WITH THE SYSTEM WILL BE FAIRLY DRY
WITH PWATS GENERALLY ONE QUARTER INCH OR LESS THEREFORE NO
PRECIPITATION IS EXPECTED. ANOTHER UPPER WAVE WILL DROP INTO THE
REGION THURSDAY NIGHT AND FRIDAY AND WILL HELP CARVE A LONG WAVE
TROUGH OUT ACROSS THE NORTHERN PLAINS AND INTO THE EASTERN CONUS.
THIS WILL BE ENHANCED AS HUDSON BAY UPPER LOW DROPS SOUTH INTO THE
UPPER GREAT LAKES. 850 MB TEMPERATURES OVER THE STATE WILL BE
AROUND -16C BY MID DAY FRIDAY. THE COLD AIR MASS WILL BE
RELATIVELY DEEP AND WILL BE ABLE TO MIX WELL. THEREFORE DESPITE
THE COLD AIR MASS...DEEP MIXING TO NEAR 850 MB WILL ALLOW
TEMPERATURES RISE INTO THE UPPER TEENS TO UPPER 20S. SATURDAY AND
SUNDAY WILL SEE GRADUAL MODERATION AS A WEAK RIDGE MOVES INTO THE
STATE IN RESPONSE TO A STRONG SHORT WAVE DIVING INTO THE
INTER MOUNTAIN WEST.
&&
.AVIATION...11/18Z
LOW PRESSURE OVER EASTERN LAKE SUPERIOR WILL MOVE INTO ONTARIO THIS
AFTERNOON AS WEAK HIGH PRESSURE BUILDS INTO THE AREA. PRESSURE
GRADIENT WILL GRADUALLY SLACKEN AS LOW RETREATS. AREAS OF MVFR CIGS
WILL LIFT OUT OF THE AREA WITH THE LOW AS WINDS DIMINISH. SOME
-SHSN AND BLSN IN THE KMCW AND KALO AREAS WILL ABATE AFTER 21Z.
CLEARING TONIGHT WITH WINDS BECOMING LIGHT WEST...THEN SOUTHWEST
LATE.
&&
.DMX WATCHES/WARNINGS/ADVISORIES...WIND ADVISORY UNTIL 4 PM CST THIS
AFTERNOON FOR BLACK HAWK-BREMER-BUTLER-CERRO GORDO- EMMET-FRANKLIN-
GRUNDY-HAMILTON-HANCOCK-HARDIN-HUMBOLDT-KOSSUTH-PALO ALTO-
POCAHONTAS-TAMA-WEBSTER-WINNEBAGO-WORTH-WRIGHT.
&&
$$
SHORT TERM...MS FEB 13
LONG TERM...DONAVON
AVIATION...MS FEB 13
AREA FORECAST DISCUSSION
NWS QUAD CITIES IA IL
1123 AM CST MON FEB 11 2013
.AVIATION...
MVFR CONDITIONS WILL BE SEEN AT KCID/KDBQ/KMLI THROUGH SUNRISE
BEFORE IMPROVING TO VFR. KDBQ MAY SEE SHSN THAT BRIEFLY LOWERS
VSBYS. INTERNALLY...THE MODELS DO NOT SHOW ANY SIGNIFICANT
SUBSIDENCE THAT WOULD HELP BREAK UP THE CLOUD COVER OVERNIGHT AND
SATELLITE SHOWS EXTENSIVE CLOUDS BACK INTO THE DAKOTAS. WINDS WILL
DECREASE THROUGH 00Z/12 AND SHOULD BE 10 KTS OR LESS AFTER SUNSET.
HIGH PRESSURE BUILDING INTO THE MIDWEST AFT 12Z/12 SHOULD BREAK UP
THE CLOUDS AND ALLOW VFR CONDITIONS WITH LIGHT WINDS. ..08..
&&
.PREV DISCUSSION... /ISSUED 1028 AM CST MON FEB 11 2013/
UPDATE...
BASED ON SATELLITE TRENDS AND WHAT RECENT RAP TRENDS ARE
SUGGESTING...CLOUDS SHOULD START BREAKING UP ACROSS THE SOUTHERN
CWFA DURING THE AFTERNOON HOURS WHILE THEY REMAIN IN PLACE ACROSS
THE NORTH.
RAP TRENDS INDICATE LAPSE RATES WILL REMAIN QUITE STEEP THROUGH
THE AFTERNOON BUT 925MB WINDS AND THE OVERALL GRADIENT
DECREASES/RELAXES RESPECTIVELY. THE OVERALL WIND ADVISORY WILL
REMAIN IN PLACE BASED ON THIS BUT WINDS SHOULD SLOWLY DECREASE
FROM NOW THROUGH MID AFTERNOON. ..08..
PREV DISCUSSION... /ISSUED 238 AM CST MON FEB 11 2013/
SYNOPSIS...
STRONG LOW PRESSURE WAS LOCATED OVER NORTHWEST WISCONSIN EARLY
THIS MORNING. THE STRONG CYCLONIC FLOW AROUND THE LOW WAS SUPPORTING
VERY WINDY CONDITIONS TO THE WEST AND SOUTHWEST. THE STRONGEST
WINDS WERE OCCURRING NORTH OF I80 WHERE SUSTAINED SPEEDS WERE IN
THE 30 TO 35 PLUS MPH RANGE WITH GUSTS OF 40 TO 50 MPH.
SNOW SHOWERS WERE ALSO OCCURRING IN THE STRONG CYCLONIC FLOW. THE
SHOWERS WERE REDUCING VISIBILITIES ALONG THE HIGHWAY 20 CORRIDOR TO MILE AT
TIMES WHILE FURTHER SOUTH SCATTERED FLURRIES WERE OCCURRING.
SHORT TERM...TODAY AND TONIGHT...
VERY WINDY CONDITIONS WILL CONTINUE THROUGH MUCH OF THE DAY AS THE
WISCONSIN LOW MOVES INTO SOUTHWEST ONTARIO BY LATE THIS AFTERNOON.
MODELS ARE STILL SHOWING WEST WINDS AS HIGH A 50KTS THIS MORNING
IN THE WELL MIXED SURFACE TO NEARLY 850MB LAYER WITH WINDS IN THIS
LAYER DIMINISHING DURING DURING THE AFTERNOON. THIS SUPPORTS
CONTINUING THE WIND ADVISORY THROUGH 21Z TODAY. EXPECT 40 TO 50
MPH GUSTS THIS MORNING THEN GRADUALLY DIMINISHING THIS AFTERNOON.
THE STRONGEST WIND ARE EXPECTED TO OCCUR ALONG AND NORTH OF I80
THIS MORNING. WRAP AROUND SNOW SHOWERS WILL ALSO CONTINUE THROUGH
THE DAY MAINLY NORTH OF HIGHWAY 30. SOME MINOR ACCUMULATIONS CAN/T
BE RULED OUT...PROBABLY LESS THAN A HALF INCH. THE EDGE OF THE
WRAP AROUND CLOUDS EXTENDS SOUTH INTO CENTRAL MO AND WEST THROUGH
EASTERN NE EARLY THIS MORNING. THE BACK EDGE IN NE WAS CREEPING
EAST AND CURRENT TIMING SUGGESTS IT COULD REACH SOUTHEAST IA THIS
MORNING. HOWEVER...ANY CLEARING SHOULD BE BRIEF WITH CU/SC
REDEVELOPING GIVEN THE STEEP LOW LEVEL LAPSE RATES. CLEARING
SHOULD RESUME LATE THIS AFTERNOON AS THE CONVECTIVE CLOUDS
DISSIPATE AND THE BETTER LOW LEVEL MOISTURE MOVES NORTHEAST. THIS
EVENING THE SURFACE PRESSURE GRADIENT WILL CONTINUE TO RELAX AHEAD
OF WEAK SURFACE RIDGE MOVING INTO CENTRAL IOWA. CLOUDS WILL ALSO
MOVE NORTHEAST OF THE AREA DURING THE EVENING WITH CLEAR SKIES
EXPECTED OVERNIGHT. WITH CLOUDS AND ONGOING COLD AIR ADVECTION
WITH SHOULD SEE ABOUT A 10 DEGREE RECOVERY IN TEMPERATURES...PUTTING
HIGHS MAINLY IN THE 30S. TONIGHT UPPER TEENS TO MID 20S LOOK
REASONABLE WITH THE EXPECTED CLEARING AND DIMINISHING WIND.
DLF
LONG TERM...TUESDAY THROUGH SUNDAY...
FORECAST FOCUS ON QUIET WEATHER EARLY TO MIDDLE PORTION OF THIS WEEK
THEN TURNING COLDER LATE IN THE WEEK INTO NEXT WEEKEND.
TUESDAY THROUGH THURSDAY...SPLIT FLOW ALLOWING FOR SOUTHERN STREAM
STORM SYSTEM TO REMAIN UN-PHASED AS IT PUSHES QUICKLY INTO THE MID
ATLANTIC STATES ON WEDNESDAY AND THEN OUT TO SEA. THIS SYSTEM
COMBINED WITH A VERY INTENSE STORM IN THE GULF OF ALASKA PUMPS UP A
FULL LATITUDE RIDGE FROM THE WEST COAST OF THE UNITED STATES INTO
WESTERN CANADA. THIS BEGINS DEEPENING THE DOWNSTREAM TROUGH INTO THE
NORTHERN PLAINS/UPPER MIDWEST BY THURSDAY. A STRONG COLD FRONT WILL
BE PUSHING INTO THE DVN CWA ON THURSDAY BUT AHEAD OF THE FRONT
TEMPERATURES WILL WARM UP INTO THE 40S ON WEDNESDAY.
THURSDAY NIGHT AND FRIDAY...DEEPENING TROUGH IN THE EAST AND RIDGE
IN THE ROCKIES WILL TAP ARCTIC AIR AND A RETURN TO COLDER WEATHER
FOR THE MIDWEST. VERY COLD AIR ALOFT MAY ALLOW FOR AT LEAST
SCATTERED SNOW SHOWERS. LOWS WILL BE IN THE TEENS NORTH AND 20S
SOUTH WHILE HIGHS ON FRIDAY WILL BE ONLY IN THE 20S AT MOST
LOCATIONS. THE LACK OF SNOW COVER ACROSS MUCH OF THE CWA WILL KEEP
TEMPERATURES FROM REALLY TAKING A NOSE DIVE.
FRIDAY NIGHT THROUGH SUNDAY...PROGRESSIVE PATTERN WILL PUSH THE
EASTERN TROUGH FARTHER TO THE EAST BY SUNDAY WHILE RIDGE MOVES INTO
THE PLAINS. TEMPERATURES SHOULD BEGIN TO MODERATE SOME BY SUNDAY.
FRIDAY NIGHT AND SATURDAY LOOK TO BE QUITE COLD WITH LOWS DROPPING
INTO THE SINGLE DIGITS NORTH AND TEENS SOUTH WHILE HIGHS ON SATURDAY
WILL BE IN THE 20S. 850 MB TEMPERATURES DROP TO -18C IN PORTIONS OF
THE CWA. ON SUNDAY...HIGHS SHOULD PUSH BACK INTO THE LOWER 30S IN
OUR SOUTHERN COUNTIES BUT REMAINING IN THE 20S NORTH.
HAASE
&&
.DVN WATCHES/WARNINGS/ADVISORIES...
IA...WIND ADVISORY UNTIL 3 PM CST THIS AFTERNOON FOR BENTON-BUCHANAN-
CEDAR-CLINTON-DELAWARE-DES MOINES-DUBUQUE-HENRY IA-IOWA-
JACKSON-JEFFERSON-JOHNSON-JONES-KEOKUK-LEE-LINN-LOUISA-
MUSCATINE-SCOTT-VAN BUREN-WASHINGTON.
IL...WIND ADVISORY UNTIL 3 PM CST THIS AFTERNOON FOR BUREAU-CARROLL-
HANCOCK-HENDERSON-HENRY IL-JO DAVIESS-MCDONOUGH-MERCER-
PUTNAM-ROCK ISLAND-STEPHENSON-WARREN-WHITESIDE.
MO...WIND ADVISORY UNTIL 3 PM CST THIS AFTERNOON FOR CLARK-SCOTLAND.
&&
$$
AREA FORECAST DISCUSSION
NWS QUAD CITIES IA IL
1028 AM CST MON FEB 11 2013
.UPDATE...
BASED ON SATELLITE TRENDS AND WHAT RECENT RAP TRENDS ARE
SUGGESTING...CLOUDS SHOULD START BREAKING UP ACROSS THE SOUTHERN
CWFA DURING THE AFTERNOON HOURS WHILE THEY REMAIN IN PLACE ACROSS
THE NORTH.
RAP TRENDS INDICATE LAPSE RATES WILL REMAIN QUITE STEEP THROUGH
THE AFTERNOON BUT 925MB WINDS AND THE OVERALL GRADIENT
DECREASES/RELAXES RESPECTIVELY. THE OVERALL WIND ADVISORY WILL
REMAIN IN PLACE BASED ON THIS BUT WINDS SHOULD SLOWLY DECREASE
FROM NOW THROUGH MID AFTERNOON. ..08..
&&
.PREV DISCUSSION... /ISSUED 538 AM CST MON FEB 11 2013/
AVIATION...
DEEP LOW PRESSURE WILL MOVE FROM WESTERN WI INTO THE NORTHERN GREAT
LAKES BY THIS MORNING. WEST TO NORTHWEST WINDS BEHIND THE
DEPARTING LOW WILL CONTINUE TO BE VERY STRONG...WITH SUSTAINED
WINDS OF 20 TO 30 KTS...GUSTING TO 35 TO 40KTS AT TIMES INTO THIS
AFTERNOON. WINDS WILL DECREASE TO 20KTS...GUST 30 KTS AROUND
SUNSET AND THEN TO AROUND 10KTS BY MIDNIGHT. FLURRIES OR POSSIBLE
LIGHT SNOW SHOWERS ARE EXPECTED AROUND DBQ THROUGH THIS
MORNING. VISIBILITIES COULD DROP TO 1 TO 2 MILES IN SOME OF THE
HEAVIER SNOW SHOWERS. CLOUDS BASES WERE IN THE 3000 FT TO 3500 FT
RANGE OVER THE SOUTHWEST HALF OF THE FORECAST AREA WITH BASES WITH
RANGING FROM 1500 TO 3000 FT BASES TO THE NORTHEAST EARLY THIS
MORNING. THE VFR CIGS SHOULD CONTINUE TO SPREAD EAST THIS
MORNING WITH VFR CIGS EXPECTED OVER MUCH OF THE AREA BY 18Z. SKIES
WILL BE CLEARING LATE THIS AFTERNOON AND EARLY THIS EVENING.
DLF
PREV DISCUSSION... /ISSUED 238 AM CST MON FEB 11 2013/
SYNOPSIS...
STRONG LOW PRESSURE WAS LOCATED OVER NORTHWEST WISCONSIN EARLY
THIS MORNING. THE STRONG CYCLONIC FLOW AROUND THE LOW WAS SUPPORTING
VERY WINDY CONDITIONS TO THE WEST AND SOUTHWEST. THE STRONGEST
WINDS WERE OCCURRING NORTH OF I80 WHERE SUSTAINED SPEEDS WERE IN
THE 30 TO 35 PLUS MPH RANGE WITH GUSTS OF 40 TO 50 MPH.
SNOW SHOWERS WERE ALSO OCCURRING IN THE STRONG CYCLONIC FLOW. THE
SHOWERS WERE REDUCING VISIBILITIES ALONG THE HIGHWAY 20 CORRIDOR TO MILE AT
TIMES WHILE FURTHER SOUTH SCATTERED FLURRIES WERE OCCURRING.
SHORT TERM...TODAY AND TONIGHT...
VERY WINDY CONDITIONS WILL CONTINUE THROUGH MUCH OF THE DAY AS THE
WISCONSIN LOW MOVES INTO SOUTHWEST ONTARIO BY LATE THIS AFTERNOON.
MODELS ARE STILL SHOWING WEST WINDS AS HIGH A 50KTS THIS MORNING
IN THE WELL MIXED SURFACE TO NEARLY 850MB LAYER WITH WINDS IN THIS
LAYER DIMINISHING DURING DURING THE AFTERNOON. THIS SUPPORTS
CONTINUING THE WIND ADVISORY THROUGH 21Z TODAY. EXPECT 40 TO 50
MPH GUSTS THIS MORNING THEN GRADUALLY DIMINISHING THIS AFTERNOON.
THE STRONGEST WIND ARE EXPECTED TO OCCUR ALONG AND NORTH OF I80
THIS MORNING. WRAP AROUND SNOW SHOWERS WILL ALSO CONTINUE THROUGH
THE DAY MAINLY NORTH OF HIGHWAY 30. SOME MINOR ACCUMULATIONS CAN/T
BE RULED OUT...PROBABLY LESS THAN A HALF INCH. THE EDGE OF THE
WRAP AROUND CLOUDS EXTENDS SOUTH INTO CENTRAL MO AND WEST THROUGH
EASTERN NE EARLY THIS MORNING. THE BACK EDGE IN NE WAS CREEPING
EAST AND CURRENT TIMING SUGGESTS IT COULD REACH SOUTHEAST IA THIS
MORNING. HOWEVER...ANY CLEARING SHOULD BE BRIEF WITH CU/SC
REDEVELOPING GIVEN THE STEEP LOW LEVEL LAPSE RATES. CLEARING
SHOULD RESUME LATE THIS AFTERNOON AS THE CONVECTIVE CLOUDS
DISSIPATE AND THE BETTER LOW LEVEL MOISTURE MOVES NORTHEAST. THIS
EVENING THE SURFACE PRESSURE GRADIENT WILL CONTINUE TO RELAX AHEAD
OF WEAK SURFACE RIDGE MOVING INTO CENTRAL IOWA. CLOUDS WILL ALSO
MOVE NORTHEAST OF THE AREA DURING THE EVENING WITH CLEAR SKIES
EXPECTED OVERNIGHT. WITH CLOUDS AND ONGOING COLD AIR ADVECTION
WITH SHOULD SEE ABOUT A 10 DEGREE RECOVERY IN TEMPERATURES...PUTTING
HIGHS MAINLY IN THE 30S. TONIGHT UPPER TEENS TO MID 20S LOOK
REASONABLE WITH THE EXPECTED CLEARING AND DIMINISHING WIND.
DLF
LONG TERM...TUESDAY THROUGH SUNDAY...
FORECAST FOCUS ON QUIET WEATHER EARLY TO MIDDLE PORTION OF THIS WEEK
THEN TURNING COLDER LATE IN THE WEEK INTO NEXT WEEKEND.
TUESDAY THROUGH THURSDAY...SPLIT FLOW ALLOWING FOR SOUTHERN STREAM
STORM SYSTEM TO REMAIN UN-PHASED AS IT PUSHES QUICKLY INTO THE MID
ATLANTIC STATES ON WEDNESDAY AND THEN OUT TO SEA. THIS SYSTEM
COMBINED WITH A VERY INTENSE STORM IN THE GULF OF ALASKA PUMPS UP A
FULL LATITUDE RIDGE FROM THE WEST COAST OF THE UNITED STATES INTO
WESTERN CANADA. THIS BEGINS DEEPENING THE DOWNSTREAM TROUGH INTO THE
NORTHERN PLAINS/UPPER MIDWEST BY THURSDAY. A STRONG COLD FRONT WILL
BE PUSHING INTO THE DVN CWA ON THURSDAY BUT AHEAD OF THE FRONT
TEMPERATURES WILL WARM UP INTO THE 40S ON WEDNESDAY.
THURSDAY NIGHT AND FRIDAY...DEEPENING TROUGH IN THE EAST AND RIDGE
IN THE ROCKIES WILL TAP ARCTIC AIR AND A RETURN TO COLDER WEATHER
FOR THE MIDWEST. VERY COLD AIR ALOFT MAY ALLOW FOR AT LEAST
SCATTERED SNOW SHOWERS. LOWS WILL BE IN THE TEENS NORTH AND 20S
SOUTH WHILE HIGHS ON FRIDAY WILL BE ONLY IN THE 20S AT MOST
LOCATIONS. THE LACK OF SNOW COVER ACROSS MUCH OF THE CWA WILL KEEP
TEMPERATURES FROM REALLY TAKING A NOSE DIVE.
FRIDAY NIGHT THROUGH SUNDAY...PROGRESSIVE PATTERN WILL PUSH THE
EASTERN TROUGH FARTHER TO THE EAST BY SUNDAY WHILE RIDGE MOVES INTO
THE PLAINS. TEMPERATURES SHOULD BEGIN TO MODERATE SOME BY SUNDAY.
FRIDAY NIGHT AND SATURDAY LOOK TO BE QUITE COLD WITH LOWS DROPPING
INTO THE SINGLE DIGITS NORTH AND TEENS SOUTH WHILE HIGHS ON SATURDAY
WILL BE IN THE 20S. 850 MB TEMPERATURES DROP TO -18C IN PORTIONS OF
THE CWA. ON SUNDAY...HIGHS SHOULD PUSH BACK INTO THE LOWER 30S IN
OUR SOUTHERN COUNTIES BUT REMAINING IN THE 20S NORTH.
HAASE
&&
.DVN WATCHES/WARNINGS/ADVISORIES...
IA...WIND ADVISORY UNTIL 3 PM CST THIS AFTERNOON FOR BENTON-BUCHANAN-
CEDAR-CLINTON-DELAWARE-DES MOINES-DUBUQUE-HENRY IA-IOWA-
JACKSON-JEFFERSON-JOHNSON-JONES-KEOKUK-LEE-LINN-LOUISA-
MUSCATINE-SCOTT-VAN BUREN-WASHINGTON.
IL...WIND ADVISORY UNTIL 3 PM CST THIS AFTERNOON FOR BUREAU-CARROLL-
HANCOCK-HENDERSON-HENRY IL-JO DAVIESS-MCDONOUGH-MERCER-
PUTNAM-ROCK ISLAND-STEPHENSON-WARREN-WHITESIDE.
MO...WIND ADVISORY UNTIL 3 PM CST THIS AFTERNOON FOR CLARK-SCOTLAND.
&&
$$
AREA FORECAST DISCUSSION
NWS DES MOINES IA
542 AM CST MON FEB 11 2013
...UPDATED AVIATION DISCUSSION...
.SHORT TERM /TODAY/...
MAIN FORECAST CONCERN TODAY IS WITH
WINDS...AND LIGHT SNOW SHOWERS/FZDZ ACROSS NORTHERN IOWA. VERTICALLY
STACKED LOW WILL CONTINUE TO PUSH EASTWARD THROUGH THE DAY AND
PRESSURE GRADIENT BEGINS TO RELAX DURING THE AFTERNOON HOURS.
NAM/GFS BUFR SOUNDINGS SUGGEST SOME LIGHT SNOW SHOWERS OR FLURRIES
OVER NORTHERN IOWA THROUGH 18Z BUT RAP SHOWING LOSS OF ICE
INTRODUCTION IN THE COLUMN PERIODICALLY DURING THE MORNING. SEVERAL
CURRENT OBSERVATIONS ACROSS NORTHERN IOWA REPORTING DZ/UP SUGGESTING
THIS IS ALREADY OCCURRING. FORCING REMAINS WEAK BUT LOOKS TO BE
ENOUGH TO WARRANT THE MENTION OF PATCHY FZDZ ACROSS THE NORTHEAST
THROUGH 18Z.
WENT CLOSE TO GUIDANCE TODAY FOR MAX TEMPERATURES AS MODELS ARE IN
GOOD AGREEMENT AND FELT NO REASON TO DEVIATE MUCH FROM THEM. THIS
RESULTED IN TWEAKING TEMPS UP SLIGHTLY ACROSS THE SOUTH. NOT
EXPECTING STRATUS TO CLEAR OUT ACROSS THE SOUTHWEST UNTIL AFTER 21Z
WHEN THE PRESSURE GRADIENT BEGINS TO WEAKEN. KEPT OVERCAST OVER THE
NORTH TO EAST THROUGH 00Z TUESDAY AS LOW LEVEL MOISTURE REMAINS
PERSISTENT WITHIN THE CAA.
.LONG TERM /TONIGHT THROUGH SUNDAY/...
THE UPPER LOW PRESSURE WILL CONTINUE TO RACE OFF TO THE EAST
TONIGHT AND BE NEAR MAIN BY 12Z TUESDAY MORNING. THIS WILL ALLOW
MUCH DRIER AIR TO FILTER INTO THE STATE AS BROAD AREA OF HIGH
PRESSURE SHIFTS EAST INTO THE MIDWEST. GENERAL TRENDS FOR TUESDAY
AND WEDNESDAY ARE WARMER. THE DRY AIR WILL WARM NICELY ON TUESDAY
UNDER SOUTHWEST FLOW. THE FLOW WILL BECOME MORE DOWN SLOPE ORIENTED
TUESDAY NIGHT INTO WEDNESDAY AHEAD A VIGOROUS UPPER WAVE THAT WILL
ARRIVE ALONG WITH AN ASSOCIATED COLD FRONT WEDNESDAY NIGHT.
TEMPERATURES ON WEDNESDAY WILL BE IN THE MID TO UPPER 40S OVER THE
CENTRAL AND SOUTH AND A FEW LOCATIONS MAY HIT 50 IF ENOUGH SUN IS
AVAILABLE.
THE UPPER WAVE WILL PASS THROUGH WEDNESDAY NIGHT INTO THURSDAY.
GUSTY NORTHWEST WINDS WILL KEEP COLD ADVECTION IN PLACE THROUGH
THE DAY THURSDAY AND MAY HAVE SLOWLY FALLING TEMPERATURES DURING
THE AFTERNOON. THE AIR MASS WITH THE SYSTEM WILL BE FAIRLY DRY
WITH PWATS GENERALLY ONE QUARTER INCH OR LESS THEREFORE NO
PRECIPITATION IS EXPECTED. ANOTHER UPPER WAVE WILL DROP INTO THE
REGION THURSDAY NIGHT AND FRIDAY AND WILL HELP CARVE A LONG WAVE
TROUGH OUT ACROSS THE NORTHERN PLAINS AND INTO THE EASTERN CONUS.
THIS WILL BE ENHANCED AS HUDSON BAY UPPER LOW DROPS SOUTH INTO THE
UPPER GREAT LAKES. 850 MB TEMPERATURES OVER THE STATE WILL BE
AROUND -16C BY MID DAY FRIDAY. THE COLD AIR MASS WILL BE
RELATIVELY DEEP AND WILL BE ABLE TO MIX WELL. THEREFORE DESPITE
THE COLD AIR MASS...DEEP MIXING TO NEAR 850 MB WILL ALLOW
TEMPERATURES RISE INTO THE UPPER TEENS TO UPPER 20S. SATURDAY AND
SUNDAY WILL SEE GRADUAL MODERATION AS A WEAK RIDGE MOVES INTO THE
STATE IN RESPONSE TO A STRONG SHORT WAVE DIVING INTO THE
INTER MOUNTAIN WEST.
&&
.AVIATION...11/12Z
TIGHT PRESSURE GRADIENT WILL CONTINUE TO PRODUCE VERY WINDY
CONDITIONS THROUGH THE DAY BEFORE WINDS DIMINISH PAST 00Z TUESDAY AS
THE LOW MOVES EAST AND ALLOW THE GRADIENT TO WEAKEN. OCCASIONAL -SN
WILL PERSIST THROUGH MIDDAY AFFECTING MAINLY MCW/ALO WITH IFR VIS AT
TIMES. MVFR STRATUS IS LIKELY TO PERSIST THROUGH MUCH OF THE DAY AS
WELL.
&&
.DMX WATCHES/WARNINGS/ADVISORIES...
WIND ADVISORY UNTIL NOON CST TODAY FOR IAZ004>007-015>017-
023>028-033>039-044>050-057>062-074-075-086.
&&
$$
SHORT TERM...PODRAZIK
LONG TERM...DONAVON
AVIATION...PODRAZIK
AREA FORECAST DISCUSSION
NWS DES MOINES IA
357 AM CST MON FEB 11 2013
.SHORT TERM /TODAY/...
MAIN FORECAST CONCERN TODAY IS WITH
WINDS...AND LIGHT SNOW SHOWERS/FZDZ ACROSS NORTHERN IOWA. VERTICALLY
STACKED LOW WILL CONTINUE TO PUSH EASTWARD THROUGH THE DAY AND
PRESSURE GRADIENT BEGINS TO RELAX DURING THE AFTERNOON HOURS.
NAM/GFS BUFR SOUNDINGS SUGGEST SOME LIGHT SNOW SHOWERS OR FLURRIES
OVER NORTHERN IOWA THROUGH 18Z BUT RAP SHOWING LOSS OF ICE
INTRODUCTION IN THE COLUMN PERIODICALLY DURING THE MORNING. SEVERAL
CURRENT OBSERVATIONS ACROSS NORTHERN IOWA REPORTING DZ/UP SUGGESTING
THIS IS ALREADY OCCURRING. FORCING REMAINS WEAK BUT LOOKS TO BE
ENOUGH TO WARRANT THE MENTION OF PATCHY FZDZ ACROSS THE NORTHEAST
THROUGH 18Z.
WENT CLOSE TO GUIDANCE TODAY FOR MAX TEMPERATURES AS MODELS ARE IN
GOOD AGREEMENT AND FELT NO REASON TO DEVIATE MUCH FROM THEM. THIS
RESULTED IN TWEAKING TEMPS UP SLIGHTLY ACROSS THE SOUTH. NOT
EXPECTING STRATUS TO CLEAR OUT ACROSS THE SOUTHWEST UNTIL AFTER 21Z
WHEN THE PRESSURE GRADIENT BEGINS TO WEAKEN. KEPT OVERCAST OVER THE
NORTH TO EAST THROUGH 00Z TUESDAY AS LOW LEVEL MOISTURE REMAINS
PERSISTENT WITHIN THE CAA.
.LONG TERM /TONIGHT THROUGH SUNDAY/...
THE UPPER LOW PRESSURE WILL CONTINUE TO RACE OFF TO THE EAST
TONIGHT AND BE NEAR MAIN BY 12Z TUESDAY MORNING. THIS WILL ALLOW
MUCH DRIER AIR TO FILTER INTO THE STATE AS BROAD AREA OF HIGH
PRESSURE SHIFTS EAST INTO THE MIDWEST. GENERAL TRENDS FOR TUESDAY
AND WEDNESDAY ARE WARMER. THE DRY AIR WILL WARM NICELY ON TUESDAY
UNDER SOUTHWEST FLOW. THE FLOW WILL BECOME MORE DOWN SLOPE ORIENTED
TUESDAY NIGHT INTO WEDNESDAY AHEAD A VIGOROUS UPPER WAVE THAT WILL
ARRIVE ALONG WITH AN ASSOCIATED COLD FRONT WEDNESDAY NIGHT.
TEMPERATURES ON WEDNESDAY WILL BE IN THE MID TO UPPER 40S OVER THE
CENTRAL AND SOUTH AND A FEW LOCATIONS MAY HIT 50 IF ENOUGH SUN IS
AVAILABLE.
THE UPPER WAVE WILL PASS THROUGH WEDNESDAY NIGHT INTO THURSDAY.
GUSTY NORTHWEST WINDS WILL KEEP COLD ADVECTION IN PLACE THROUGH
THE DAY THURSDAY AND MAY HAVE SLOWLY FALLING TEMPERATURES DURING
THE AFTERNOON. THE AIR MASS WITH THE SYSTEM WILL BE FAIRLY DRY
WITH PWATS GENERALLY ONE QUARTER INCH OR LESS THEREFORE NO
PRECIPITATION IS EXPECTED. ANOTHER UPPER WAVE WILL DROP INTO THE
REGION THURSDAY NIGHT AND FRIDAY AND WILL HELP CARVE A LONG WAVE
TROUGH OUT ACROSS THE NORTHERN PLAINS AND INTO THE EASTERN CONUS.
THIS WILL BE ENHANCED AS HUDSON BAY UPPER LOW DROPS SOUTH INTO THE
UPPER GREAT LAKES. 850 MB TEMPERATURES OVER THE STATE WILL BE
AROUND -16C BY MID DAY FRIDAY. THE COLD AIR MASS WILL BE
RELATIVELY DEEP AND WILL BE ABLE TO MIX WELL. THEREFORE DESPITE
THE COLD AIR MASS...DEEP MIXING TO NEAR 850 MB WILL ALLOW
TEMPERATURES RISE INTO THE UPPER TEENS TO UPPER 20S. SATURDAY AND
SUNDAY WILL SEE GRADUAL MODERATION AS A WEAK RIDGE MOVES INTO THE
STATE IN RESPONSE TO A STRONG SHORT WAVE DIVING INTO THE
INTER MOUNTAIN WEST.
&&
.AVIATION...11/06Z
AREAS OF LIGHT SNOW WILL PERSIST ACROSS NORTHERN IOWA OVERNIGHT WITH
A FEW FLURRIES IN THE SOUTH. VISIBILITIES WILL BE MVFR TO IFR IN
THE NORTH WITH THE LIGHT SNOW BUT SHOULD IMPROVE TO VFR ON MONDAY AS
THE PCPN ENDS. CEILINGS WILL REMAIN IN PLACE THROUGH MUCH OF MONDAY
ACROSS THE FORECAST AREA WITH MVFR CEILINGS IN THE NORTH AND VFR
CONDITIONS IN THE SOUTH. TIGHT PRESSURE GRADIENT WILL MAINTAIN
STRONG WEST TO NORTHWEST WINDS OVERNIGHT INTO MONDAY BEFORE A
GRADUAL WEAKENING INTO MONDAY EVENING AS THE GRADIENT RELAXES.
&&
.DMX WATCHES/WARNINGS/ADVISORIES...
WIND ADVISORY UNTIL NOON CST TODAY FOR IAZ004>007-015>017-
023>028-033>039-044>050-057>062-074-075-086.
&&
$$
SHORT TERM...PODRAZIK
LONG TERM...DONAVON
AVIATION...COGIL
AREA FORECAST DISCUSSION
NWS LOUISVILLE KY
1230 PM EST MON FEB 11 2013
...Updated Aviation Discussion...
.Forecast Update...
Issued at 1040 AM EST Mon Feb 11 2013
Ran a quick update this morning mainly to increase cloud cover
across the southeast. A rather thick upper level deck looks as if
it will stream across the Cumberland area through much of the day as
another wave rides up along the departing frontal boundary. Also
tweaked temperature and dewpoint grids to account for current trends.
The jury is still out on the decision for an advisory late this
morning into this afternoon. Louisville (SDF) gusted to 36 mph
earlier this morning and Frankfort just recently gusted to 37 mph.
However, both the 12Z NAM and the latest RAP soundings continue to
advertise only about 35 knots at the top of the mixed layer late
this morning, staying nearly steady or slowly weakening through the
afternoon despite a deepening mixed layer. Will continue to monitor
observations over the next few hours, but current thinking is that
this event will best be handled with an SPS (although an isolated 40
mph gust is certainly possible).
&&
.Short Term (Today - Tuesday)...
Issued at 315 AM EST Mon Feb 11 2013
Light showers/drizzle redeveloped late last night and early this
morning. This is currently in the process of exiting the forecast
area, with dry air and reduced cloud cover working into the region.
A vertically stacked low pressure system will meander eastward
across the Great Lakes today. This will set up a tight pressure
gradient at the surface, with even stronger winds aloft. Partly to
mostly sunny skies and cold air advection aloft will aid mixing
those winds to the surface. Sustained speeds between 15 and 25 mph
are expected, with some gusts near 40 mph possible. Southern Indiana
and north-central Kentucky will experience the strongest winds, with
slightly weaker winds across south-central Kentucky. The peak period
for the strongest winds will be from about mid morning through the
afternoon. Wind speeds will decrease this evening, as the pressure
gradient relaxes with surface high pressure and ridging aloft taking
control.
The high temperature forecast for today is tricky, with the ongoing
cold air advection. We remained quite mild overnight, but cooler air
is approaching from the west. Believe highs in the mid to upper 40s
will be possible across southern Indiana, with lower 50s across
north-central Kentucky and mid 50s across south-central and
east-central Kentucky. Some of these highs, particularly in the
north, may occur this morning and hold steady or only increase a
degree or two with solar heating this afternoon. Lows tonight will
drop into the upper 20s and lower 30s, with mostly clear skies.
Typical cooler locations could dip into the mid 20s. Expect dry
conditions, light westerly winds and temperatures ranging from the
mid 40s to low 50s Tuesday. Clouds will increase through the day,
ahead of our next system.
.Long Term (Tuesday Night - Sunday)...
Issued at 300 AM EST Mon Feb 11 2013
...Light Wintry Precip Possible Wednesday Morning...
The main concern in the long term period will be the possibility of
light wintry precip Wed morning as an upper trough moves through the
Ohio Valley. Still quite a bit of model spread on the track of the
QPF field as it passes through our region, but have sided with a
track similar to the 0Z GFS, GFS ensembles, and GEM. The 0Z ECMWF
looks too suppressed compared to previous model runs and the 0Z NAM
is much farther north than previous model runs. Certainly going
with a consistency forecast here on the track of precipitation. One
common theme among 0Z model guidance regardless of track is the
slower timing of this weather system through the region. This
theme combined with very dry low layers at onset of precip were
evidence enough to delay precip arrival by around 4-6 hrs from the
previous forecast. Looks like we should see some virga entering the
region by around midnight Tues night, but precip shouldn`t start
reaching the ground until closer to sunrise with the best coverage
during the late morning/early afternoon hours Wed. Precipitation
will be quick hitting and on its way out by late afternoon or early
evening Wed. As far as precip type, boundary layer temps will be
our determining factor as it looks like we`ll see ice crystal growth
aloft with the main slug of moisture. With mild antecedent air and
ground temps, think that most of the precip should fall as a cold
rain. However, thermal profiles indicate that southern Indiana and
north central KY may be cold enough Wed morning in a 2-5 hr window
around sunrise for some snowflakes to fall. Also models do indicate
some weak deformation with this system so if some heavier bands of
precip set up in an environment with boundary layer temps close to
freezing, we could see a change over to all snow briefly in heavier
bands. Still with ground temps running in the lower 40s and low
temps expected in the lower 30 to mid 30s across the area, think
that any light snow accums would be short lived and shouldn`t cause
much of a travel issue. Still stay abreast of the forecast for Wed
morning`s commute as any changes in the thermal profile will affect
ptype and potentially travel impacts. High temps on Wed are
expected to top out in the lower 40s.
Expect dry conditions for Thurs as zonal flow will dominate our
region while a potent trough digs across the Plains states. This
trough will push into the Midwest for the weekend creating a cool
down. We`ll go from highs in the 40s to around 50 Thurs/Fri. to
highs in the 30s Sat/Sun. Although no big weather makers look to
impact the Ohio Valley with this upper trough, we will keep 20% POPs
in the forecast as hard to time shortwaves that may produce light
precip look possible Fri/Sat.
&&
.Aviation (18Z TAF Issuance)...
Issued at 1230 PM EST Mon Feb 11 2013
VFR conditions will prevail through the TAF period. The main issue
over the next several hours will continue to be strong winds, as an
area of low pressure pushes east through the Great Lakes. Expect
westerly winds to continue at 15-20 knots, with gusts approaching 30
knots for the remainder of the afternoon across KLEX and KSDF.
Winds will be slightly lower at KBWG, with 10-15 knots sustained and
gusts just above 20 knots.
Otherwise, winds will die down this evening, becoming variable by
Tuesday as a surface ridge slides through the Ohio Valley.
Some high clouds will begin to approach from the southwest toward
the end of the TAF period in advance of the next system.
&&
.LMK WATCHES/WARNINGS/ADVISORIES...
IN...NONE.
KY...NONE.
$$
Update...........KD
Short Term.......MJP
Long Term........AMS
Aviation.........KD
AREA FORECAST DISCUSSION
NWS LOUISVILLE KY
1040 AM EST MON FEB 11 2013
.Forecast Update...
Issued at 1040 AM EST Mon Feb 11 2013
Ran a quick update this morning mainly to increase cloud cover
across the southeast. A rather thick upper level deck looks as if
it will stream across the Cumberland area through much of the day as
another wave rides up along the departing frontal boundary. Also
tweaked temperature and dewpoint grids to account for current trends.
The jury is still out on the decision for an advisory late this
morning into this afternoon. Louisville (SDF) gusted to 36 mph
earlier this morning and Frankfort just recently gusted to 37 mph.
However, both the 12Z NAM and the latest RAP soundings continue to
advertise only about 35 knots at the top of the mixed layer late
this morning, staying nearly steady or slowly weakening through the
afternoon despite a deepening mixed layer. Will continue to monitor
observations over the next few hours, but current thinking is that
this event will best be handled with an SPS (although an isolated 40
mph gust is certainly possible).
&&
.Short Term (Today - Tuesday)...
Issued at 315 AM EST Mon Feb 11 2013
Light showers/drizzle redeveloped late last night and early this
morning. This is currently in the process of exiting the forecast
area, with dry air and reduced cloud cover working into the region.
A vertically stacked low pressure system will meander eastward
across the Great Lakes today. This will set up a tight pressure
gradient at the surface, with even stronger winds aloft. Partly to
mostly sunny skies and cold air advection aloft will aid mixing
those winds to the surface. Sustained speeds between 15 and 25 mph
are expected, with some gusts near 40 mph possible. Southern Indiana
and north-central Kentucky will experience the strongest winds, with
slightly weaker winds across south-central Kentucky. The peak period
for the strongest winds will be from about mid morning through the
afternoon. Wind speeds will decrease this evening, as the pressure
gradient relaxes with surface high pressure and ridging aloft taking
control.
The high temperature forecast for today is tricky, with the ongoing
cold air advection. We remained quite mild overnight, but cooler air
is approaching from the west. Believe highs in the mid to upper 40s
will be possible across southern Indiana, with lower 50s across
north-central Kentucky and mid 50s across south-central and
east-central Kentucky. Some of these highs, particularly in the
north, may occur this morning and hold steady or only increase a
degree or two with solar heating this afternoon. Lows tonight will
drop into the upper 20s and lower 30s, with mostly clear skies.
Typical cooler locations could dip into the mid 20s. Expect dry
conditions, light westerly winds and temperatures ranging from the
mid 40s to low 50s Tuesday. Clouds will increase through the day,
ahead of our next system.
.Long Term (Tuesday Night - Sunday)...
Issued at 300 AM EST Mon Feb 11 2013
...Light Wintry Precip Possible Wednesday Morning...
The main concern in the long term period will be the possibility of
light wintry precip Wed morning as an upper trough moves through the
Ohio Valley. Still quite a bit of model spread on the track of the
QPF field as it passes through our region, but have sided with a
track similar to the 0Z GFS, GFS ensembles, and GEM. The 0Z ECMWF
looks too suppressed compared to previous model runs and the 0Z NAM
is much farther north than previous model runs. Certainly going
with a consistency forecast here on the track of precipitation. One
common theme among 0Z model guidance regardless of track is the
slower timing of this weather system through the region. This
theme combined with very dry low layers at onset of precip were
evidence enough to delay precip arrival by around 4-6 hrs from the
previous forecast. Looks like we should see some virga entering the
region by around midnight Tues night, but precip shouldn`t start
reaching the ground until closer to sunrise with the best coverage
during the late morning/early afternoon hours Wed. Precipitation
will be quick hitting and on its way out by late afternoon or early
evening Wed. As far as precip type, boundary layer temps will be
our determining factor as it looks like we`ll see ice crystal growth
aloft with the main slug of moisture. With mild antecedent air and
ground temps, think that most of the precip should fall as a cold
rain. However, thermal profiles indicate that southern Indiana and
north central KY may be cold enough Wed morning in a 2-5 hr window
around sunrise for some snowflakes to fall. Also models do indicate
some weak deformation with this system so if some heavier bands of
precip set up in an environment with boundary layer temps close to
freezing, we could see a change over to all snow briefly in heavier
bands. Still with ground temps running in the lower 40s and low
temps expected in the lower 30 to mid 30s across the area, think
that any light snow accums would be short lived and shouldn`t cause
much of a travel issue. Still stay abreast of the forecast for Wed
morning`s commute as any changes in the thermal profile will affect
ptype and potentially travel impacts. High temps on Wed are
expected to top out in the lower 40s.
Expect dry conditions for Thurs as zonal flow will dominate our
region while a potent trough digs across the Plains states. This
trough will push into the Midwest for the weekend creating a cool
down. We`ll go from highs in the 40s to around 50 Thurs/Fri. to
highs in the 30s Sat/Sun. Although no big weather makers look to
impact the Ohio Valley with this upper trough, we will keep 20% POPs
in the forecast as hard to time shortwaves that may produce light
precip look possible Fri/Sat.
&&
.Aviation (12Z TAF Issuance)...
Issued at 620 AM EST Mon Feb 11 2013
Expect VFR conditions at all TAF sites this forecast period. Could
see a few Cu at the top of a relatively deep mixing layer later this
afternoon, along with a some high clouds from a southern stream
system. However, the big issue today will be gusty west winds. Winds
will continue a transition to west-southwest and be quite gusty, as
the pressure gradient strengthens with a vertically stacked low
meandering east across the Great Lakes. Wind speeds will peak just
over 20 knots at BWG and just over 30 knots at SDF and LEX. Gusts
should settle down around sunset, with speeds decreasing overnight
as high pressure takes control.
&&
.LMK WATCHES/WARNINGS/ADVISORIES...
IN...NONE.
KY...NONE.
$$
Update...........KD
Short Term.......MJP
Long Term........AMS
Aviation.........MJP
AREA FORECAST DISCUSSION
NWS LOUISVILLE KY
1228 AM EST MON FEB 11 2013
...Updated Aviation Discussion...
.Forecast Update...
Issued at 910 PM EST Sun Feb 10 2013
Not seeing much to increase forecast confidence as the evening wears
on. Precip development has been limited at best, but the mesoscale
models continue to generate chance POPs later this evening. Might
otherwise be inclined to drastically lower POPs with this evening
update, but the RUC and HRRR both seem to have a handle on what is
out there now, and start to show development near the I-65 corridor
around 03-04Z.
Already updated to clean up evening wording and remove thunder, and
lowered POPs to chance at that time. Otherwise the forecast has been
left as-is and most tweaks for the rest of the evening will be in
the grids.
&&
.Short Term (Tonight - Monday Night)...
Issued at 300 PM EST Sun Feb 10 2013
A vertically stacked low continues to churn across the Central
Plains this afternoon. Out ahead of this low, a ridge has amplified
over the Ohio Valley, allowing a warm and rather moist airmass to
push north into the Ohio Valley.
Showers and embedded thunderstorms have pushed into the western half
of the CWA this afternoon. A notable weakening trend has occurred
with this activity over the past few hours as it has pushed east,
due to it outrunning the better elevated instability and the
strongest forcing pushing north. This weakening trend will continue
through the remainder of the afternoon, but much of the area still
has a chance of seeing an isolated thunderstorm as the main line
pushes east.
Winds out ahead of this line have been breezy, especially across
areas that received a break in the clouds early this afternoon.
Simpson County for example, gusted to 37 knots as they broke out in
some sunshine. However, winds should continue to slowly slacken as
this system rolls through and saturates the column, limiting any
mixing. Some of the stronger convection has mixed down some higher
momentum air this afternoon, but the potential for any damaging
gusts appears very low as a stout cap remains in place.
After the main line rolls through late this afternoon into the
early evening, attention will then turn to the southwest as another
weak shortwave ejects out of the southwest flow aloft. Most
high-res models are indicating some low-topped convective showers
developing along the surface front as this wave rides up along it
tonight. Therefore, will increase pops once again this evening into
tonight to account for these showers.
The surface front will clear the area and dry air will work into the
region by Monday morning. The only issue on Monday will be the
gusty wind potential, especially across southern Indiana and the
northern Bluegrass. Currently have winds gusting to around 35 MPH
during the afternoon hours, as mostly sunny skies and cold air
advection aloft helps aid in mixing. These gusts are just below
advisory criteria and the potential for an advisory across the
northern CWA will need to be revisited in coming forecasts. With
the expected deep mixing and a good amount of sunshine, have gone a
bit above guidance for highs on Monday (upper 40s to middle 50s).
Winds will begin to die down Monday night as a surface ridge pushes
into the region. Lows Monday night will drop into the upper 20s and
lower 30s, with mostly clear skies.
.Long Term (Tuesday - Sunday)...
Issued at 255 PM EST Sun Feb 10 2013
The first concern in the long term is, of course, the Tuesday
night/Wednesday system.
Looking at the models, the EC has had slightly better run-to-run
consistency than the GFS, especially on Wednesday, with the path of
the surface low that will be going by to our south Tuesday
night/Wednesday. The EC also has been leading the way with
verification of surface temperatures and dew points lately. Still,
the EC isn`t perfect and it looks like the model is probably
ejecting the low eastward too quickly. We will also need to dial in
a bit of a northward correction to account for the possibility that
the models might be taking this southern stream system a bit too far
south. So, given all that, will go with a surface low path from
Louisiana Tuesday evening to between Birmingham and Atlanta
Wednesday morning to the VA/NC coast Wednesday evening.
The upper trof associated with this system is a narrow appendage
poking southwestward from the main upper trof well to our north. As
a result it is quite far away from the polar vortex over the
Canadian Archipelago and so there isn`t much cold air for this
system to work with. So, despite the favorable track of the low to
give us a snowstorm, it looks like we son`t have the requisite cold
air and we should actually see rain in the south and a mix in the
north.
Of course, for a snowstorm one also needs a rich source of
moisture. The GFS`s QPF is getting no real support from the EC,
GEM, HPC, or GEFS and there is quite a bit of spread among the
perturbation plumes in the GEFS (and SREF for that matter). So,
won`t latch on to the GFS`s robust QPF numbers at this time and
instead will go with more conservative amounts. Also supporting
lower QPF values is a layer of surface-700hPa dry air that will have
to be overcome Tuesday night before precipitation reaches the
surface. In addition, the GFS tends to count virga as QPF. In the
grids we have gone with 24-hour totals Tuesday night-Wednesday
ranging from around a tenth of an inch in the north to a quarter of
an inch far south. Even in the north where some snow will be
possible, only a portion of that QPF will be snow. Ground
temperatures will be warm from temperatures in the 45-50 degree
range Tuesday afternoon, and highs Wednesday afternoon should get up
to around 40. So, other than maybe a few tricky hours around the
Wednesday morning commute, overall this system shouldn`t be too
bad. Of course, we`ll need to keep an eye on it and the forecasts
will surely evolve as we get closer to Tuesday night.
A large upper trof will then dig into the Plains late in the week
and invade the eastern half of the country over the weekend. This
trof will have a direct connection to the main upper low over the
Canadian Arctic and so will bring in colder air.
Most of the precipitation associated with this trof will remain to
our north in areas of better relative humidity and upper support.
The best chance for precipitation for us will likely be with
shortwave trofs diving down the backside of the trof. Those types
of small-scale features are very difficult to accurately forecast so
far out in the future, so will keep PoPs low at this time.
Our warmest day should be Thursday with highs around 50. Once the
late week upper trof comes in it will drop daily highs down into the
30s for the weekend. By Sunday morning we`ll probably dip into the
teens, which is about ten degrees below normal for mid February.
&&
.Aviation (06Z TAF Issuance)...
Issued at 1228 AM EST Mon Feb 11 2013
Last little bit of light rain/drizzle is pushing into east-central
KY. This will only impact LEX with lower cigs, which were
experienced upstream. The back edge of the 1000-1500ft AGL cigs is
currently across southern IL and western KY. If timed correctly,
this should get into SDF and BWG within a couple of hours, and reach
LEX around 10Z. All sites will improve to VFR, with breezy winds
overnight keeping the atmosphere mixed. Expect mainly scattered Cu
or Sc at the top of a relatively deep mixing layer later this
afternoon. Winds will transition to west-southwest and be quite
gusty, as a vertically stacked low meanders east across the Great
Lakes today. Wind speeds will peak over 20 knots at BWG and perhaps
just over 30 knots at SDF and LEX. Gusts should settle down around
sunset, with speeds decreasing overnight as high pressure takes
control.
&&
.LMK WATCHES/WARNINGS/ADVISORIES...
IN...NONE.
KY...NONE.
$$
Update...........RAS
Short Term.......KD
Long Term........13
Aviation.........MJP
AREA FORECAST DISCUSSION...CORRECTION TO ADD AVIATION
NWS SHREVEPORT LA
146 AM CST MON FEB 11 2013
.UPDATE...
KSHV 88D SHOWING SOME LIGHT RAIN ALONG I-20 FROM TYLER...CONFIRMED
WITH ASOS...TO STILL VIRGA OVER LONGVIEW AND JUST SOUTH OF
TEXARKANA. THE WATER VAPOR IMAGERY SHOWS A SPEED MAX OVER
MEXICO...NEARING THE RIO GRANDE...BRINGING A BIT OF LIFT OVER NE
TX BACK OVER THE COLD FRONT. WE HAVE UPDATED 6-12Z AND 12-18Z POP
AND WEATHER GRIDS WITH LIGHT RAIN NORTH...AS T/TD SPREADS ARE
STILL PRETTY HARDY AND WE WILL CONTINUE WITH OUR CHANCE SHOWERS IN
THE FRONTAL VICINITY ALONG AND SOUTH OF I-20. NO OTHER CHANGES
ATTM. /24/
&&
.AVIATION...
MOSTLY VFR FLIGHT CATEGORIES EXPECTED THROUGH THE EARLY MORNING
HOURS AROUND 11/14 UTC BUT WITH LIGHT RAIN OR EMBEDDED SHOWERS
SPREADING RAPIDLY WEST TO EAST. CEILINGS WILL BE RUNNING AROUND 7
KFT TO 10 KFT WITH SOME LOWERING OF CLOUDS AT TIMES TO NEAR 5 KFT.
ALL OF THE TERMINAL SITES ALONG AND SOUTH OF INTERSTATE 20 LOOK TO
BE AFFECTED BY THE RAIN OR SHOWERS WITH VISIBILITIES NEAR 6 STATUTE
MILES OR MORE THROUGH 11/14 UTC. THE CLOUD BASE WILL BE GRADUALLY
LOWERING...TRANSITIONING TO MVFR/IFR NEAR MID DAY TO EARLY
AFTERNOON...AND REMAINING AT THE LOWER CATEGORIES THROUGH THE END OF
THE TERMINAL FORECAST PERIOD ENDING AROUND 12/06 UTC AND LIKELY TO
12/12 UTC. TERMINAL FORECAST FOR KTXK AND KELD WILL BE MORE LIKELY
TO REMAIN AT VFR UNTIL 12/06 UTC. SURFACE WIND LIGHT AND VARIABLE OR
NORTHERLY LESS THAN 7 KNOTS UNTIL AFTER 11/15 UTC WHEN THE WINDS
BECOME NORTHEAST TO EAST 7 TO 11 KNOTS. WINDS WILL LOWER SLIGHTLY
AFTER 12/00 UTC BUT REMAIN AROUND 6 TO 9 KNOTS. /06/
&&
.PREV DISCUSSION... /ISSUED 920 PM CST SUN FEB 10 2013/
DISCUSSION...
SURFACE ANALYSIS THIS EVENING INDICATED THAT OUR FRONTAL BOUNDARY
WAS STALLED NEAR A MEM...MLU...LCH LINE. MUCH DRIER AIR IN THE
LOWER LEVELS OF THE ATMOSPHERE HAS INFILTRATED THE REGION FROM THE
WEST BUT STILL DEALING WITH A FAIRLY MOIST PROFILE ACROSS OUR
EXTREME EASTERN ZONES. ALSO BEGINNING TO SEE SOME REDEVELOPMENT OF
WIDELY SCATTERED SHOWERS ACROSS OUR EXTREME EASTERN ZONES AS WELL.
FOR THIS REASON...HAVE LEFT POPS PRETTY MUCH UNCHANGED THROUGH THE
NIGHT ADVERTISING CHANCE POPS TO OUR SOUTH AND EAST. A QUICK LOOK
AT THE 00Z NAM AS WELL AS THE LATEST RAP SHOWS THAT SCATTERED
SHOWERS WILL BE POSSIBLE ALL NIGHT...MAINLY ACROSS OUR SOUTHEAST
ZONES. THESE MODELS ALSO SUGGEST THAT THE FRONTAL BOUNDARY WILL
FINALLY GET SHOVED SOUTH AND EAST OVERNIGHT WHICH WILL ALLOW FOR
SOME DRIER AIR TO PUSH THROUGH AT LEAST OUT EASTERN MOST ZONES.
HOWEVER...MID AND HIGH LEVEL CLOUDS SHOULD HANG ON FOR THE
REMAINDER OF THE NIGHT ACROSS ALL BUT OUR EXTREME NW ZONES.
DESPITE THE DRIER AIR...FEEL LIKE THE CLOUD COVER SHOULD HOLD
TEMPS UP SOMEWHAT OVERNIGHT. MOS GUIDANCE WAS RUNNING A LITTLE TOO
COOL WITH ITS 03Z TEMPS ACROSS A FEW SELECTED CITIES THIS EVENING
SO HAVE BUMPED UP OVERNIGHT MINS JUST A DEGREE OR TWO ACROSS A FEW
LOCATIONS.
DID MAKE SOME ADJUSTMENTS TO DEWPOINTS GIVEN THE SLOWER
INFILTRATION OF DRIER AIR INTO OUR EASTERN ZONES THIS EVENING AND
SOME COSMETIC CHANGES TO SKY GRIDS. OTHERWISE...NO OTHER CHANGES
WERE NECESSARY THIS EVENING.
UPDATE OUT SHORTLY...13.
AVIATION...
MOSTLY VFR FLIGHT WEATHER TONIGHT AND MONDAY. HOWEVER...AREAS SOUTH
AND EAST OF A KMLU TO KLFK LINE WILL EXPERIENCE LOW VFR CIGS...
BETWEEN 4 AND 6 KFT...WITH ISOLATED SHOWERS AND TSTMS. EXPECT SOME
BRIEF VISIBILITY RESTRICTIONS TO NEAR IFR IN THE STRONGER
CONVECTION. THIS AREA OF LOW VFR CIGS AND CONVECTION WILL GRADUALLY
SPREAD TO THE NORTH ON MONDAY...TO NEAR A KELD TO KTYR LINE BY
12/00Z. SURFACE WIND LIGHT AND VARIABLE TONIGHT...AND NORTHEAST
5 TO 10 KTS MONDAY.
/14/
&&
.PRELIMINARY POINT TEMPS/POPS...
SHV 49 61 46 57 40 / 20 20 50 60 20
MLU 51 59 46 55 41 / 40 40 50 60 40
DEQ 35 61 38 49 34 / 20 20 30 60 40
TXK 42 63 44 51 36 / 20 20 40 60 30
ELD 44 61 43 54 37 / 20 20 40 60 40
TYR 48 61 46 55 37 / 20 20 60 60 20
GGG 49 62 46 55 38 / 20 20 60 60 20
LFK 52 63 50 60 41 / 30 40 60 60 20
&&
.SHV WATCHES/WARNINGS/ADVISORIES...
AR...NONE.
LA...NONE.
OK...NONE.
TX...NONE.
&&
$$
24/06
AREA FORECAST DISCUSSION
NWS GAYLORD MI
930 PM EST TUE FEB 12 2013
.SYNOPSIS...
ISSUED AT 415 PM EST TUE FEB 12 2013
WEAK HIGH PRESSURE WILL BUILD INTO THE NORTHERN GREAT LAKES TONIGHT
AND WEDNESDAY. THIS PATTERN WILL GENERATE ABOVE NORMAL TEMPERATURES
AND OCCASIONAL FLURRIES...ACROSS THE NORTHERN MICHIGAN INTO THURSDAY.
HOWEVER...THE NEXT SYSTEM TO INFLUENCE THE GREAT LAKES ARRIVES
THURSDAY...BEFORE QUICKLY LIFTING NORTHEAST INTO QUEBEC FRIDAY. THIS
SYSTEM WILL GENERATE ANOTHER ROUND OF SNOW ACROSS NORTHERN
MICHIGAN THURSDAY...WHILE ALSO USHERING IN MUCH COLDER CONDITIONS
FRIDAY AND INTO THE WEEKEND. ACCUMULATING LAKE EFFECT SNOW CAN BE
EXPECTED OVER THE WESTERN GREAT LAKES THIS WEEKEND.
&&
.UPDATE...
ISSUED AT 930 PM EST TUE FEB 12 2013
FLURRIES HAVE TEMPORARILY ENDED ACROSS NW LWR MICHIGAN LATE THIS
EVENING THANKS TO BUILDING SUBSIDENCE AND SHALLOWING OF THE LOW
LEVEL MOIST LAYER. LATEST IR SATELLITE DOES SHOW A LINE OF COOLER
CLOUD TOPS OVER CENTRAL UPR MICHIGAN ASSOCIATED WITH A WEAK VORT
LOBE AND A NARROW BAND OF MID LEVEL MOISTURE. EXPECT THESE
FEATURES WILL LEND TO REDEVELOPMENT OF ADDITIONAL LAKE EFFECT
FLURRIES OVERNIGHT FOR FAR NRN AND NW LWR MICHIGAN AS WELL AS
PORTIONS OF ERN UPR MICHIGAN...STILL UNDER THE DIRECTION OF SW
LOW LEVEL FLOW. TEMPS CONTINUE TO FALL THRU THE 20S...ON THEIR WAY
TO THE UPPER TEENS AND LOWER 20S FOR OVERNIGHT LOWS.
UPDATE ISSUED AT 645 PM EST TUE FEB 12 2013
LAKE EFFECT FLURRIES CONTINUE TO STREAM INTO FAR NRN AND NW LWR
MICHIGAN THIS EVENING UNDER THE DIRECTION OF LOW LEVEL SW FLOW.
LOW CLOUDS REMAIN TRAPPED BELOW THE SUBSIDENCE INVERSION...
MAINTAINING OVC SKIES ACROSS OUR ENTIRE CWA EVEN AWAY FROM ANY
LAKE INFLUENCES. VERY LITTLE WILL CHANGE THRU THE NIGHT AS LOW
LEVEL MOISTURE/CLOUDS REMAINS STUCK BELOW THE INVERSION AND SW
FLOW CONTINUES TO PRODUCE FLURRIES FOR FAR NRN AND NW LWR
MICHIGAN. OVERNIGHT LOWS IN THE UPPER TEENS TO LOWER 20S LOOKS
REASONABLE GIVEN CURRENT SURFACE DWPTS IN THAT VCNTY.
&&
.SHORT TERM...(THIS EVENING THROUGH WEDNESDAY)
ISSUED AT 415 PM EST TUE FEB 12 2013
COLD AIR ADVECTION HAS ABOUT MAXED OUT BEHIND YESTERDAY`S DEPARTING
STORM...WITH LATEST HIGH RES RUC ANALYSIS PLACING CIRCA -11C H85
TEMPERATURES ACROSS THE NORTH WOODS. DESPITE EXCEEDINGLY LOW
INVERSIONS (H85 PER SAME RUC ANALYSIS)...MOISTURE DEPTH EXTENDING
TO THE LOW END OF THE FAVORED DGZ CONTINUES TO KICK OFF WIDESPREAD
FLURRIES IN FAVORED WEST FLOW LAKE AREAS. ABUNDANT LOW LEVEL
MOISTURE ALSO LEADING TO A MAINLY CLOUDY DAY...WITH ANY SUBSTANTIAL
CLEARING OF NOTE BACK ACROSS WISCONSIN. THIS CLEARING APPEARS TIED
TO DOWNWARD FORCING ON BACKSIDE OF RATHER COMPACT SHORTWAVE
PINWHEELING EAST INTO NORTHERN LAKE MICHIGAN. NO SIGNIFICANT
CONCERNS THROUGH THE SHORT TERM (WEDNESDAY)...ALTHOUGH LINGERING
FLURRIES AND CLOUD TRENDS WILL NEED ADDRESSING.
WISCONSIN SHORTWAVE WILL STEADILY AND RAPIDLY PUSH ACROSS THE AREA
THIS EVENING...AND LACK OF ANY APPRECIABLE MOISTURE SHOULD PRECLUDE
MUCH...IF ANY...LAKE OR SYNOPTIC RESPONSE. H85 TEMPERATURES SLOWLY
WARM IN DEVELOPING WEAK SOUTHWEST FLOW WAA REGIME...REACHING THE
NEGATIVE SINGLE DIGITS BY MORNING. NAM-WRF BUFFER SOUNDINGS SHOW LOW
LEVEL MOISTURE FALLING BELOW -10C ISOTHERM...WHICH COMBINED WITH
LOWERING DELTA T/S...WOULD SUPPORT A QUICK DEMISE TO ONGOING
FLURRIES. NOT WILLING TO BITE ON THIS JUST YET...AND PREFER TO KEEP
FLURRIES IN THE FORECAST...SIMPLY FOLLOWING THE WINDS FOR THERE
PLACEMENT (WHICH SUGGESTS THEY SHOULD CONFINE THEMSELVES IN FAVORED
SOUTHWEST FLOW AREAS THROUGH THE NIGHT). CLOUD COVER REMAINS A
FORMIDABLE CHALLENGE...ESPECIALLY GIVEN WHAT IS OCCURRING BEHIND
UPSTREAM WAVE. DO HAVE SOME TREPIDATION GOING TOO AGGRESSIVE WITH
CLOUDS OVERNIGHT...ESPECIALLY IN NON-FAVORED LAKE AREAS. SUBTLE WARM
ADVECTION AND POST-WAVE DOWNWARD RESPONSE JUST MAY WORK IN TANDEM TO
FORCE MUCH MORE CLEARING THAN THIS FORECAST WILL SUGGEST. WILL
TREND PARTLY CLOUDY ACROSS EASTERN UPPER AND NORTHEAST LOWER AS A
STARTING POINT...WITH KNOWLEDGE THAT COMPLETELY CLOUDY OR CLEAR IS
THE MORE LIKELY OUTCOME. TEMPERATURES...OF COURSE...HIGHLY DEPENDENT
ON HOW THIS WHOLE CLOUD THING UNFOLDS. MID AND UPPER TEENS MAY BE
SEVERAL DEGREES TOO "WARM". WE SHALL SEE.
SAME STORY HEADING INTO WEDNESDAY...WITH SOME LINGERING FLURRIES AND
MOSTLY TO PARTLY CLOUDY SKIES. LOW LEVEL MODIFICATION
CONTINUES...SUGGESTING HIGHS IN THE LOWER AND MIDDLE 30S.
.LONG TERM...(WEDNESDAY NIGHT THROUGH TUESDAY)
ISSUED AT 415 PM EST TUE FEB 12 2013
MAIN FORECAST CONCERNS WILL BE POTENTIAL FOR ACCUMULATING LAKE
ENHANCED SNOWS STARTING THURSDAY AND CONTINUING INTO THE
WEEKEND.
THE LATEST HEMISPHERIC ANALYSIS SHOWS A STABLE 3-WAVE PATTERN WITH
LARGE SCALE TROUGHING OVER CENTERED OVER JAMES BAY...EAST ASIA
/AROUND 120E/ AND CENTRAL EUROPE. A VERY STRONG ZONAL JET REMAINS
OVER EAST ASIA AND THE WESTERN PACIFIC...WITH A SLIT FLOW OVER THE
EASTERN PACIFIC EXTENDING INTO THE WEST COAST. THE SPLIT FLOW MERGES
TO FORM A FASTER JET THE SOUTHEASTERN U.S.
THURSDAY...AN AMPLIFYING PATTERN IS EXPECTED WITH STRONG PACIFIC JET
TO BEEF UP THE WEST COAST RIDGE...RESULTING IN INCREASED TROUGHING
OVER THE EASTERN TWO THIRDS OF THE CONUS BY THURSDAY. SHORT WAVE
ENERGY IS EXPECTED TO ROUND THE TOP OF THE RIDGE ON
WEDNESDAY...BEFORE DIVING INTO THE GREAT LAKES BY THURSDAY. AN
ASSOCIATED SURFACE RESPONSE/CLIPPER SYSTEM WILL MOVE THOUGH THE
GREAT LAKES...BRINGING NORTHERN MICHIGAN THE NEXT CHANCE OF SOME
LIGHT SNOW. THE AMOUNT OF MOISTURE THIS SYSTEM HAS TO WORK WITH IS
NOT TERRIBLE...WITH MODEL SOUNDINGS SHOWING P-WATS OF AROUND 0.3 TO
0.4 INCHES ACROSS THE CWA. THE DEGREE OF FORCING REMAINS IN SOME
QUESTION...WITH TWO DISTINCT AREAS OF ENHANCED PVA EXPECTED TO MOVE
THROUGH THE REGION EMBEDDED IN THE SHEARED PIECE OF ENERGY. THE
NAM/GFS WANT TO SPIN UP A STRONGER LOW WITH THIS FEATURE...WHILE THE
ECMWF/GEM KEEP THE SURFACE LOW MORE BENIGN. PREFER THE LATTER OF THE
SOLUTIONS...GIVEN THAT THESE TWO PIECES OF ENERGY DO NOT NECESSARILY
PHASE TOGETHER. OVERALL LOOKING LIKE A 1 TO 2..PERHAPS LOCALLY 3
INCH SNOW EVENT. RAPIDLY CHANGING FLOW AND WARMISH AIR ALOFT WITH
H85 TEMPS BETWEEN -5 TO -8C LOOK TO KEEP A MAJOR DAMPER OF ANY LAKE
ENHANCEMENT. SNOW MAY BE ALSO BE SLOW TO ACCUMULATE ON ROAD SURFACES
WITH SURFACE TEMPS AT OR SLIGHTLY ABOVE FREEZING...WITH THE MORE
AGGRESSIVE NAM/GFS SUGGESTING HIGHS IN THE MID TO UPPER 30S FOR
THURSDAY. THIS WOULD HAVE RAIN/SNOW MIX IMPLICATIONS FOR THE LOWER
ELEVATIONS OF THE CWA...BUT PREFER THE MORE COOLER...LESS AMPLIFIED
SOLUTIONS FOR NOW.
THURSDAY NIGHT AND FRIDAY...FORCING BEGINS TO PUSH EAST OF THE AREA
BY LATE THURSDAY AFTERNOON WITH STRONG COLD AIR ADVECTION ENSUING
ACROSS THE CWA THURSDAY NIGHT INTO FRIDAY. THIS WILL RAMP UP THE
LAKE EFFECT SNOW MACHINE DURING THIS TIMEFRAME. MODELS ARE NOT IN
THE BEST AGREEMENT WITH THE NAM/GFS MORE NORTHWESTERLY THAN THE NNW
FLOW DEPICTED BY THE ECMWF. MODEST INVERSION HEIGHTS AND DEEPEST
MOISTURE MOVING OUT SHOULD KEEP MAJOR LAKE SNOW ACCUMULATIONS IN
CHECK...HOWEVER SEVERAL INCHES OF ACCUMULATION LOOK LIKELY FOR THE
NW/NNW FAVORED SNOW BELTS THROUGH FRIDAY. H85 TEMPS FALL TO -15 TO
-18C DURING THE DAY FRIDAY...WITH MODEL CONSENSUS SHOWING HIGHS
STRUGGLING TO MAKE IT OUT OF THE TEENS.
FRIDAY NIGHT THROUGH TUESDAY...CHILLY CONDITIONS ENSUE AS DEEP
TROUGH SETTLES INTO THE GREAT LAKES WITH MODEL CONSENSUS SHOWING H85
TEMPS IN THE -18 TO -22 RANGE ACROSS THE GREAT LAKES INTO THE DAY ON
SATURDAY. CERTAINLY PLENTY OF INSTABILITY TO KEEP THE LAKE EFFECT
SNOW MACHINE GOING...WITH POCKETS OF DEEPER H85-H7 MOISTURE
ASSOCIATED WITH EMBEDDED SHORTWAVES ROUNDING THE LONGER WAVE TROUGH
AND CONTINUED NORTHWEST TO NORTH NORTHWEST FLOW. AT THE
LEAST...SEVERAL INCHES OF ACCUMULATION LOOK LIKELY IN THE NW TO NNW
FAVORED SNOW BELTS WITH THIS PATTERN. LOOKING AT SOME OF COOP
SNOWFALL GUIDANCE FROM THE CIPS ANALOGS FOR THE 72 HOUR PERIOD
CENTERED ON 00Z/17 SHOWS HEAVY ACCUMULATIONS FOR 3 OF THE TO 5
ANALOGS. STILL PLENTY OF DETAILS TO WORK OUT BETWEEN NOW AND THIS
WEEKEND...WITH ICE COVER OVER NORTHERN LAKE MICHIGAN AND MODEST
INVERSION HEIGHTS SERVING AS MITIGATING FACTORS FOR HEAVY
ACCUMULATIONS. STILL COULD SEE THE POSSIBILITY OF SOME HEADLINES FOR
THE FRI/SAT TIMEFRAME...AND WILL MAINTAIN THE THREAT FOR
ACCUMULATING LAKE SNOWS IN THE HWO.
SUNDAY THROUGH MONDAY...PROGRESSIVE PATTERN CONTINUES WITH DEEP
TROUGH KICKING OFF TO THE NORTHEAST AND HEIGHTS MODIFYING
SUBSTANTIALLY AS UPSTREAM RIDGING BUILDS INTO THE GREAT LAKES.
1000-850 MEAN FLOW IS PROGGED TO BACK TO THE SOUTHWEST WITH H85
TEMPS MODIFYING ENOUGH TO END THE LES THREAT...ALTHOUGH THERE MAY BE
SOME LINGER -SHSN FOR SW FAVORED FLOW AREAS INITIALLY SUNDAY
MORNING. ANOTHER CLIPPER SYSTEM LOOKS TO TRAVERSE THE AREA SUNDAY
NIGHT INTO MONDAY...HOWEVER THE BETTER MOISTURE AND FORCING LOOK TO
REMAIN OVER THE NORTHERN PORTION OF THE CWA ATTM.
MONDAY NIGHT INTO TUESDAY...NEXT TROUGH BUILDS INTO THE GREAT LAKES
WITH GFS/ECMWF DEPICTING A STORM SYSTEM DEVELOPING IN THE SOUTHERN
PLAINS AND MOVING UP THROUGH THE OHIO VALLEY INTO THE GREAT LAKES.
NOT A LOT OF CONFIDENCE OF COURSE THIS FAR OUT...ESPECIALLY WHEN
LOOKING AT SOME OF THE ENSEMBLE GUIDANCE ON THE UPPER AIR
PATTERN...BUT SOME SIGNALS ARE THERE OF SAID SYSTEM WHEN LOOKING AT
THE REANALYSIS BASED ON THE TOP GFS/CAN ENS TOP ANALOGS. SOMETHING
THAT WILL CERTAINLY NEED TO BE MONITORED.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z WEDNESDAY EVENING)
ISSUED AT 645 PM EST TUE FEB 12 2013
MVFR CIGS WILL HOLD OVER ALL NRN LWR MICHIGAN TAF SITES THRU
WEDNESDAY EVENING AS SHALLOW LOW LEVEL MOISTURE REMAINS TRAPPED
BELOW THE SUBSIDENCE INVERSION. VSBYS WILL REMAIN VFR DESPITE SOME
SW FLOW LAKE EFFECT FLURRIES STREAMING INTO PORTIONS OF FAR NRN
AND NW LWR MICHIGAN. SW WINDS WILL REMAIN AOB 10 KTS THRU THE
FORECAST PERIOD.
&&
.MARINE...
ISSUED AT 415 PM EST TUE FEB 12 2013
MARINE...VEERING WINDS TO SOUTHWEST REMAIN SOMEWHAT GUSTY HEADING
INTO THIS EVENING. MAY EVEN SEE SOME SCA PRODUCING GUSTS ALONG THE
NORTHWEST LOWER LAKE MICHIGAN COAST...ALTHOUGH DURATION DOES NOT
SUPPORT A SPECIFIC SCA HEADLINE. SOUTHWEST AND SUB-ADVISORY WINDS TO
CONTINUE THROUGH THURSDAY MORNING.
&&
.APX WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LH...NONE.
LM...NONE.
LS...NONE.
&&
$$
UPDATE...MR
SYNOPSIS...SR
SHORT TERM...MB
LONG TERM...NS
AVIATION...MR
MARINE...MB
AREA FORECAST DISCUSSION
NWS GAYLORD MI
645 PM EST TUE FEB 12 2013
.SYNOPSIS...
ISSUED AT 415 PM EST TUE FEB 12 2013
WEAK HIGH PRESSURE WILL BUILD INTO THE NORTHERN GREAT LAKES TONIGHT
AND WEDNESDAY. THIS PATTERN WILL GENERATE ABOVE NORMAL TEMPERATURES
AND OCCASIONAL FLURRIES...ACROSS THE NORTHERN MICHIGAN INTO THURSDAY.
HOWEVER...THE NEXT SYSTEM TO INFLUENCE THE GREAT LAKES ARRIVES
THURSDAY...BEFORE QUICKLY LIFTING NORTHEAST INTO QUEBEC FRIDAY. THIS
SYSTEM WILL GENERATE ANOTHER ROUND OF SNOW ACROSS NORTHERN
MICHIGAN THURSDAY...WHILE ALSO USHERING IN MUCH COLDER CONDITIONS
FRIDAY AND INTO THE WEEKEND. ACCUMULATING LAKE EFFECT SNOW CAN BE
EXPECTED OVER THE WESTERN GREAT LAKES THIS WEEKEND.
&&
.UPDATE...
ISSUED AT 645 PM EST TUE FEB 12 2013
LAKE EFFECT FLURRIES CONTINUE TO STREAM INTO FAR NRN AND NW LWR
MICHIGAN THIS EVENING UNDER THE DIRECTION OF LOW LEVEL SW FLOW.
LOW CLOUDS REMAIN TRAPPED BELOW THE SUBSIDENCE INVERSION...
MAINTAINING OVC SKIES ACROSS OUR ENTIRE CWA EVEN AWAY FROM ANY
LAKE INFLUENCES. VERY LITTLE WILL CHANGE THRU THE NIGHT AS LOW
LEVEL MOISTURE/CLOUDS REMAINS STUCK BELOW THE INVERSION AND SW
FLOW CONTINUES TO PRODUCE FLURRIES FOR FAR NRN AND NW LWR
MICHIGAN. OVERNIGHT LOWS IN THE UPPER TEENS TO LOWER 20S LOOKS
REASONABLE GIVEN CURRENT SURFACE DWPTS IN THAT VCNTY.
&&
.SHORT TERM...(THIS EVENING THROUGH WEDNESDAY)
ISSUED AT 415 PM EST TUE FEB 12 2013
COLD AIR ADVECTION HAS ABOUT MAXED OUT BEHIND YESTERDAY`S DEPARTING
STORM...WITH LATEST HIGH RES RUC ANALYSIS PLACING CIRCA -11C H85
TEMPERATURES ACROSS THE NORTH WOODS. DESPITE EXCEEDINGLY LOW
INVERSIONS (H85 PER SAME RUC ANALYSIS)...MOISTURE DEPTH EXTENDING
TO THE LOW END OF THE FAVORED DGZ CONTINUES TO KICK OFF WIDESPREAD
FLURRIES IN FAVORED WEST FLOW LAKE AREAS. ABUNDANT LOW LEVEL
MOISTURE ALSO LEADING TO A MAINLY CLOUDY DAY...WITH ANY SUBSTANTIAL
CLEARING OF NOTE BACK ACROSS WISCONSIN. THIS CLEARING APPEARS TIED
TO DOWNWARD FORCING ON BACKSIDE OF RATHER COMPACT SHORTWAVE
PINWHEELING EAST INTO NORTHERN LAKE MICHIGAN. NO SIGNIFICANT
CONCERNS THROUGH THE SHORT TERM (WEDNESDAY)...ALTHOUGH LINGERING
FLURRIES AND CLOUD TRENDS WILL NEED ADDRESSING.
WISCONSIN SHORTWAVE WILL STEADILY AND RAPIDLY PUSH ACROSS THE AREA
THIS EVENING...AND LACK OF ANY APPRECIABLE MOISTURE SHOULD PRECLUDE
MUCH...IF ANY...LAKE OR SYNOPTIC RESPONSE. H85 TEMPERATURES SLOWLY
WARM IN DEVELOPING WEAK SOUTHWEST FLOW WAA REGIME...REACHING THE
NEGATIVE SINGLE DIGITS BY MORNING. NAM-WRF BUFFER SOUNDINGS SHOW LOW
LEVEL MOISTURE FALLING BELOW -10C ISOTHERM...WHICH COMBINED WITH
LOWERING DELTA T/S...WOULD SUPPORT A QUICK DEMISE TO ONGOING
FLURRIES. NOT WILLING TO BITE ON THIS JUST YET...AND PREFER TO KEEP
FLURRIES IN THE FORECAST...SIMPLY FOLLOWING THE WINDS FOR THERE
PLACEMENT (WHICH SUGGESTS THEY SHOULD CONFINE THEMSELVES IN FAVORED
SOUTHWEST FLOW AREAS THROUGH THE NIGHT). CLOUD COVER REMAINS A
FORMIDABLE CHALLENGE...ESPECIALLY GIVEN WHAT IS OCCURRING BEHIND
UPSTREAM WAVE. DO HAVE SOME TREPIDATION GOING TOO AGGRESSIVE WITH
CLOUDS OVERNIGHT...ESPECIALLY IN NON-FAVORED LAKE AREAS. SUBTLE WARM
ADVECTION AND POST-WAVE DOWNWARD RESPONSE JUST MAY WORK IN TANDEM TO
FORCE MUCH MORE CLEARING THAN THIS FORECAST WILL SUGGEST. WILL
TREND PARTLY CLOUDY ACROSS EASTERN UPPER AND NORTHEAST LOWER AS A
STARTING POINT...WITH KNOWLEDGE THAT COMPLETELY CLOUDY OR CLEAR IS
THE MORE LIKELY OUTCOME. TEMPERATURES...OF COURSE...HIGHLY DEPENDENT
ON HOW THIS WHOLE CLOUD THING UNFOLDS. MID AND UPPER TEENS MAY BE
SEVERAL DEGREES TOO "WARM". WE SHALL SEE.
SAME STORY HEADING INTO WEDNESDAY...WITH SOME LINGERING FLURRIES AND
MOSTLY TO PARTLY CLOUDY SKIES. LOW LEVEL MODIFICATION
CONTINUES...SUGGESTING HIGHS IN THE LOWER AND MIDDLE 30S.
.LONG TERM...(WEDNESDAY NIGHT THROUGH TUESDAY)
ISSUED AT 415 PM EST TUE FEB 12 2013
MAIN FORECAST CONCERNS WILL BE POTENTIAL FOR ACCUMULATING LAKE
ENHANCED SNOWS STARTING THURSDAY AND CONTINUING INTO THE
WEEKEND.
THE LATEST HEMISPHERIC ANALYSIS SHOWS A STABLE 3-WAVE PATTERN WITH
LARGE SCALE TROUGHING OVER CENTERED OVER JAMES BAY...EAST ASIA
/AROUND 120E/ AND CENTRAL EUROPE. A VERY STRONG ZONAL JET REMAINS
OVER EAST ASIA AND THE WESTERN PACIFIC...WITH A SLIT FLOW OVER THE
EASTERN PACIFIC EXTENDING INTO THE WEST COAST. THE SPLIT FLOW MERGES
TO FORM A FASTER JET THE SOUTHEASTERN U.S.
THURSDAY...AN AMPLIFYING PATTERN IS EXPECTED WITH STRONG PACIFIC JET
TO BEEF UP THE WEST COAST RIDGE...RESULTING IN INCREASED TROUGHING
OVER THE EASTERN TWO THIRDS OF THE CONUS BY THURSDAY. SHORT WAVE
ENERGY IS EXPECTED TO ROUND THE TOP OF THE RIDGE ON
WEDNESDAY...BEFORE DIVING INTO THE GREAT LAKES BY THURSDAY. AN
ASSOCIATED SURFACE RESPONSE/CLIPPER SYSTEM WILL MOVE THOUGH THE
GREAT LAKES...BRINGING NORTHERN MICHIGAN THE NEXT CHANCE OF SOME
LIGHT SNOW. THE AMOUNT OF MOISTURE THIS SYSTEM HAS TO WORK WITH IS
NOT TERRIBLE...WITH MODEL SOUNDINGS SHOWING P-WATS OF AROUND 0.3 TO
0.4 INCHES ACROSS THE CWA. THE DEGREE OF FORCING REMAINS IN SOME
QUESTION...WITH TWO DISTINCT AREAS OF ENHANCED PVA EXPECTED TO MOVE
THROUGH THE REGION EMBEDDED IN THE SHEARED PIECE OF ENERGY. THE
NAM/GFS WANT TO SPIN UP A STRONGER LOW WITH THIS FEATURE...WHILE THE
ECMWF/GEM KEEP THE SURFACE LOW MORE BENIGN. PREFER THE LATTER OF THE
SOLUTIONS...GIVEN THAT THESE TWO PIECES OF ENERGY DO NOT NECESSARILY
PHASE TOGETHER. OVERALL LOOKING LIKE A 1 TO 2..PERHAPS LOCALLY 3
INCH SNOW EVENT. RAPIDLY CHANGING FLOW AND WARMISH AIR ALOFT WITH
H85 TEMPS BETWEEN -5 TO -8C LOOK TO KEEP A MAJOR DAMPER OF ANY LAKE
ENHANCEMENT. SNOW MAY BE ALSO BE SLOW TO ACCUMULATE ON ROAD SURFACES
WITH SURFACE TEMPS AT OR SLIGHTLY ABOVE FREEZING...WITH THE MORE
AGGRESSIVE NAM/GFS SUGGESTING HIGHS IN THE MID TO UPPER 30S FOR
THURSDAY. THIS WOULD HAVE RAIN/SNOW MIX IMPLICATIONS FOR THE LOWER
ELEVATIONS OF THE CWA...BUT PREFER THE MORE COOLER...LESS AMPLIFIED
SOLUTIONS FOR NOW.
THURSDAY NIGHT AND FRIDAY...FORCING BEGINS TO PUSH EAST OF THE AREA
BY LATE THURSDAY AFTERNOON WITH STRONG COLD AIR ADVECTION ENSUING
ACROSS THE CWA THURSDAY NIGHT INTO FRIDAY. THIS WILL RAMP UP THE
LAKE EFFECT SNOW MACHINE DURING THIS TIMEFRAME. MODELS ARE NOT IN
THE BEST AGREEMENT WITH THE NAM/GFS MORE NORTHWESTERLY THAN THE NNW
FLOW DEPICTED BY THE ECMWF. MODEST INVERSION HEIGHTS AND DEEPEST
MOISTURE MOVING OUT SHOULD KEEP MAJOR LAKE SNOW ACCUMULATIONS IN
CHECK...HOWEVER SEVERAL INCHES OF ACCUMULATION LOOK LIKELY FOR THE
NW/NNW FAVORED SNOW BELTS THROUGH FRIDAY. H85 TEMPS FALL TO -15 TO
-18C DURING THE DAY FRIDAY...WITH MODEL CONSENSUS SHOWING HIGHS
STRUGGLING TO MAKE IT OUT OF THE TEENS.
FRIDAY NIGHT THROUGH TUESDAY...CHILLY CONDITIONS ENSUE AS DEEP
TROUGH SETTLES INTO THE GREAT LAKES WITH MODEL CONSENSUS SHOWING H85
TEMPS IN THE -18 TO -22 RANGE ACROSS THE GREAT LAKES INTO THE DAY ON
SATURDAY. CERTAINLY PLENTY OF INSTABILITY TO KEEP THE LAKE EFFECT
SNOW MACHINE GOING...WITH POCKETS OF DEEPER H85-H7 MOISTURE
ASSOCIATED WITH EMBEDDED SHORTWAVES ROUNDING THE LONGER WAVE TROUGH
AND CONTINUED NORTHWEST TO NORTH NORTHWEST FLOW. AT THE
LEAST...SEVERAL INCHES OF ACCUMULATION LOOK LIKELY IN THE NW TO NNW
FAVORED SNOW BELTS WITH THIS PATTERN. LOOKING AT SOME OF COOP
SNOWFALL GUIDANCE FROM THE CIPS ANALOGS FOR THE 72 HOUR PERIOD
CENTERED ON 00Z/17 SHOWS HEAVY ACCUMULATIONS FOR 3 OF THE TO 5
ANALOGS. STILL PLENTY OF DETAILS TO WORK OUT BETWEEN NOW AND THIS
WEEKEND...WITH ICE COVER OVER NORTHERN LAKE MICHIGAN AND MODEST
INVERSION HEIGHTS SERVING AS MITIGATING FACTORS FOR HEAVY
ACCUMULATIONS. STILL COULD SEE THE POSSIBILITY OF SOME HEADLINES FOR
THE FRI/SAT TIMEFRAME...AND WILL MAINTAIN THE THREAT FOR
ACCUMULATING LAKE SNOWS IN THE HWO.
SUNDAY THROUGH MONDAY...PROGRESSIVE PATTERN CONTINUES WITH DEEP
TROUGH KICKING OFF TO THE NORTHEAST AND HEIGHTS MODIFYING
SUBSTANTIALLY AS UPSTREAM RIDGING BUILDS INTO THE GREAT LAKES.
1000-850 MEAN FLOW IS PROGGED TO BACK TO THE SOUTHWEST WITH H85
TEMPS MODIFYING ENOUGH TO END THE LES THREAT...ALTHOUGH THERE MAY BE
SOME LINGER -SHSN FOR SW FAVORED FLOW AREAS INITIALLY SUNDAY
MORNING. ANOTHER CLIPPER SYSTEM LOOKS TO TRAVERSE THE AREA SUNDAY
NIGHT INTO MONDAY...HOWEVER THE BETTER MOISTURE AND FORCING LOOK TO
REMAIN OVER THE NORTHERN PORTION OF THE CWA ATTM.
MONDAY NIGHT INTO TUESDAY...NEXT TROUGH BUILDS INTO THE GREAT LAKES
WITH GFS/ECMWF DEPICTING A STORM SYSTEM DEVELOPING IN THE SOUTHERN
PLAINS AND MOVING UP THROUGH THE OHIO VALLEY INTO THE GREAT LAKES.
NOT A LOT OF CONFIDENCE OF COURSE THIS FAR OUT...ESPECIALLY WHEN
LOOKING AT SOME OF THE ENSEMBLE GUIDANCE ON THE UPPER AIR
PATTERN...BUT SOME SIGNALS ARE THERE OF SAID SYSTEM WHEN LOOKING AT
THE REANALYSIS BASED ON THE TOP GFS/CAN ENS TOP ANALOGS. SOMETHING
THAT WILL CERTAINLY NEED TO BE MONITORED.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z WEDNESDAY EVENING)
ISSUED AT 645 PM EST TUE FEB 12 2013
MVFR CIGS WILL HOLD OVER ALL NRN LWR MICHIGAN TAF SITES THRU
WEDNESDAY EVENING AS SHALLOW LOW LEVEL MOISTURE REMAINS TRAPPED
BELOW THE SUBSIDENCE INVERSION. VSBYS WILL REMAIN VFR DESPITE SOME
SW FLOW LAKE EFFECT FLURRIES STREAMING INTO PORTIONS OF FAR NRN
AND NW LWR MICHIGAN. SW WINDS WILL REMAIN AOB 10 KTS THRU THE
FORECAST PERIOD.
&&
.MARINE...
ISSUED AT 415 PM EST TUE FEB 12 2013
MARINE...VEERING WINDS TO SOUTHWEST REMAIN SOMEWHAT GUSTY HEADING
INTO THIS EVENING. MAY EVEN SEE SOME SCA PRODUCING GUSTS ALONG THE
NORTHWEST LOWER LAKE MICHIGAN COAST...ALTHOUGH DURATION DOES NOT
SUPPORT A SPECIFIC SCA HEADLINE. SOUTHWEST AND SUB-ADVISORY WINDS TO
CONTINUE THROUGH THURSDAY MORNING.
&&
.APX WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LH...NONE.
LM...NONE.
LS...NONE.
&&
$$
UPDATE...MR
SYNOPSIS...SR
SHORT TERM...MB
LONG TERM...NS
AVIATION...MR
MARINE...MB
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
407 PM EST MON FEB 11 2013
.SHORT TERM...(THIS EVENING THROUGH TUESDAY)
ISSUED AT 406 PM EST MON FEB 11 2013
PER WATER VAPOR IMAGERY AND RUC ANALYSIS...BROAD MID LEVEL TROUGH
AND ASSOC CLOSED LOW ARE PROGRESSING STEADILY EAST OF THE UPPER
GREAT LAKES. IN RESPONSE TO INCREASED RDGG FROM THE WEST...MODELS
INDICATE INCREASING Q-VECT DIV/SUBSIDENCE SPREADING WEST TO EAST
ACROSS FCST AREA INTO THIS EVENING. COMBINATION OF MQT RADAR...VIS
SATELLITE AND AREA WEB CAMS SUGGEST ONLY LIGHT SNOW OR FLURRIES
ACROSS THE CWA. THERE IS A BETTER BAND OF LES OVER WRN LAKE SUPERIOR
AFFECTING NW WI THIS AFTERNOON WITH LIGHT TO MODERATE SNOW PER DLH
RADAR.
GIVEN THAT DEEPER MOISTURE WILL EXIT EAST TONIGHT WITH FLOW BCMG
INCREASINGLY ANTICYCLONIC...SNOW NEAR LAKE SUPERIOR SHOULD STEADILY
DIMINISH W TO E (POSSIBLY EVEN END) AS 850MB TEMPS WILL BE MARGINAL
AROUND THE THRESHOLD FOR LES. AS A RESULT OF CONTINUED DIMINISHING
TREND TO LES...EXPECT TO CANCEL REMAINING WINTER WX ADVISORIES OVER
WRN COUNTIES ON THE AFTERNOON FCST ISSUANCE. EVEN IF BAND OVER NW WI
DOES SWING INTO FAR WRN UPR MI...BELIEVE ANY INCREASE IN LES WILL BE
SHORT-LIVED AND NOT BE WORTHY OF ADVISORY HEADLINE.
LINGERING LIGHT LAKE EFFECT IS EXPECTED EAST TUE MORNING...BUT
INCREASED DRYING/RDGG FROM WEST TO EAST...WARMING 850MB TEMPS AND
WINDS BACKING TO THE SOUTHWEST WITH THE SURFACE RIDGE MOVING ACROSS
THE REGION SHOULD QUICKLY DIMINISH OR END LAKE EFFECT SNOW DURING
THE DAY TUESDAY. EXPECT CLOUDS TO GENERALLY DIMINISH AS WELL THROUGH
THE DAY WITH INCREASED RDGG. GENERALLY FOLLOWED A BLEND OF CONSENSUS
MODEL GUIDANCE FOR LOW TEMPS TONIGHT AND HIGH TEMPS ON TUESDAY.
.LONG TERM...(TUESDAY NIGHT THROUGH MONDAY)
ISSUED AT 406 PM EST MON FEB 11 2013
EXPECT NW FLOW ALOFT THROUGH MUCH OF THE LONG TERM PERIOD...WITH
SEVERAL OPEN WAVES DIVING TOWARD THE UPPER GREAT LAKES. LAKE EFFECT
SNOW SHOWERS OVER THE KEWEENAW PENINSULA...AND NEAR AND EAST OF
MUNISING NEAR LAKE SUPERIOR WILL BE COMMON.
THE NEXT SYSTEM TO INFLUENCE OUR WEATHER WILL BE IN THE FORM OF A
SFC TROUGH EXTENDING FROM THE PARENT LOW OVER HUDSON BAY. THE TROUGH
WILL SWEEP W-E ACROSS UPPER MI TUESDAY NIGHT...BEFORE EXITING TO
EASTERN ONTARIO LATE WEDNESDAY MORNING. 850MB TEMPS OF -7 TO -10C.
YET ANOTHER QUICK CLIPPER SYSTEM SET UP OVER CENTRAL ALBERTA AND
SASKATCHEWAN TUESDAY NIGHT WILL QUICKLY CROSS LAKE WINNIPEG
WEDNESDAY MORNING...AND PUSH INTO WESTERN LAKE SUPERIOR WEDNESDAY
EVENING...THEN ACROSS CENTRAL UPPER MI/LAKE SUPERIOR BY 12Z
THURSDAY...AND EASTERN UPPER MI AROUND 18Z. WHILE THE
NAM/GFS/ECMWF/SREF SHOW A SIMILAR TRACK TO THE SFC LOW...THE 11/00Z
CANADIAN IS APPROX 300MI SW OF THE CONSENSUS. WILL LIMIT THE USE OF
THE 11/00Z CANADIAN FORECAST FOR WEDNESDAY THROUGH THURSDAY. SNOW
AMOUNTS WEDNESDAY NIGHT THROUGH THURSDAY COULD ACCUMULATE 3 TO 6
INCHES OF LES FROM IWD UP THROUGH THE KEWEENAW PENINSULA...WITH SNOW
TO LIQUID RATIOS AROUND 17:1. LIGHTER AMOUNTS OF 2 TO 5 INCHES WILL
BE POSSIBLE NORTH CENTRAL...AND 1 TO 3 INCHES ELSEWHERE. WILL ADD
THE MENTION OF LIGHT TO MODERATE SNOW WITH LAKE ENHANCEMENT FOR
WEDNESDAY NIGHT THROUGH THURSDAY...BEFORE THE DGZ FALLS CLOSER TO
THE SFC AS COLDER AIR PUSHES IN...LIMITING SIGNIFICANT ACCUMULATIONS.
A WEAKENING SFC TROUGH WILL AGAIN LINGER ACROSS CENTRAL AND EASTERN
LAKE SUPERIOR THURSDAY NIGHT THROUGH SATURDAY AS STRONGER HIGH
PRESSURE SINKS ACROSS THE CENTRAL CANADA AND THE PLAINS
STATES...WITH A RIDGE EDGING INTO WESTERN UPPER MI/LAKE SUPERIOR.
THE 11/12Z GFS WAS A BIT STRONGER WITH WHAT THE ECMWF HAS AS AN OPEN
WAVE PUSHING IN FROM THE NNW SATURDAY...ACCENTUATING THE SFC LOW
OVER EASTERN LAKE SUPERIOR. EITHER WAY...LAKE EFFECT SNOW SHOWERS
WILL BE LINGERING OVER CENTRAL AND EASTERN UPPER MI NEAR LAKE
SUPERIOR. EXPECT LES TO PICK UP SIGNIFICANTLY THURSDAY AFTERNOON AND
EVENING AS COLDER AIR FILTERS IN BEHIND THE EXITING LOW ON FAVORABLE
NNW WINDS. 850MB TEMPS WILL FALL TO AROUND -17C OVER THE W HALF BY
THE END OF THE DAY THURSDAY...WITH FURTHER COOLING TO -19 TO -20C
THROUGH THE START OF THE WEEKEND. -22 TO -24C LOOKS TO BE THE
COOLEST POINT...SATURDAY AFTERNOON.
WHILE THE 11/06Z GFS AND 11/00Z ECMWF ARE PRETTY CONSISTENT UNTIL
SATURDAY...THEY BEGIN TO DIVERGE SATURDAY AFTERNOON...WITH THE GFS
DEVELOPING A LOW OVER THE CENTRAL PLAINS BECOMING OUT OF PHASE WITH
THE REST OF THE AVAILABLE MODELS. THE GOOD NEWS IS THAT THE 11/12Z
GFS LOOKS TO HAVE FIXED THIS POTENTIAL PROBLEM...AND ANOTHER
POSSIBLE STORM TOWARD THE EAST COAST FOR THE UPCOMING WEEKEND.
EXPECT A COOL RIDGE OF HIGH PRESSURE TO EDGE ACROSS THE UPPER GREAT
LAKES FOR THE WEEKEND...AS AN ELONGATED TROUGH GAINS STEAM FROM
CENTRAL CANADA THROUGH THE CENTRAL PLAINS STATES ON SUNDAY. FOR
MONDAY IT WILL BE A QUESTION AS TO IF THE SOUTHERN OR NORTHERN
STREAM WINS OUT. AT THIS POINT THE 11/00Z ECMWF LOOKS TO BE STRONGER
WITH THE SYSTEM AS A WHOLE...BUT WILL WAIT UNTIL THE TIME PERIOD
BECOMES A BIT MORE CLEAR BEFORE LEANING TO ONE SOLUTION OVER ANOTHER.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z TUESDAY AFTERNOON)
ISSUED AT 125 PM EST MON FEB 11 2013
IFR CONDITIONS WITH LAKE ENHANCED -SN SHOULD PREVAIL AT
KIWD/KCMX/KSAW THIS AFTERNOON UNDER GUSTY NNW WINDS ON BACKSIDE OF
LOW PRES SYSTEM MOVING EAST OF LAKE SUPEPIOR. MID TO LATE
AFTERNOON...IMPROVEMENT INTO THE MVFR RANGE IS EXPECTED AS THE STORM
SYSTEM CONTINUES TO MOVE EAST. MVFR CIGS MAY SCATTER OUT LATE
TONIGHT AT KIWD AS WINDS BACK TOWARD THE SW...AND PERHAPS AT KSAW
UNDER DOWNSLOPING W TO NW WINDS. LOOK FOR MVFR CIGS TO SCT OUT AT
BOTH KCMX AND KSAW BY LATE TUE MORNING WITH INCREASED SUBSIDENCE AND
RDGG.
&&
.MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 406 PM EST MON FEB 11 2013
NW GALES OVER CENTRAL LAKE SUPERIOR AIDED BY PRES RISE MAX WILL
DIMINISH BLO GALES BY LATE EVENING AS NW GRADIENT WEAKENS DUE TO LOW
DEPARTING EAST AND RDG BUILDING IN FM WEST. HIGH PRES RDG AXIS MOVG
EAST ACROSS THE LAKE WILL KEEP WINDS AOB 20 KTS OVER EAST HALF OF
LAKE SUPERIOR. WEST HALF AND FAR NCNTRL LAKE SHOULD SEE AN INCREASE
IN SW WINDS TUE AFTERNOON TO 25 KTS WITH TIGHTENING GRAD ON BACKSIDE
OF RDG AXIS.
A WEAK TROUGH STRETCHING FROM HUDSON BAY THROUGH THE UPPER GREAT
LAKES TUESDAY NIGHT WILL BE REINFORCED BY ANOTHER LOW FROM THE
NORTHWEST...THAT WILL PUSH ACROSS LAKE SUPERIOR/UPPER MI THURSDAY
MORNING INTO THURSDAY AFTERNOON...BEFORE QUICKLY EXITING INTO
SOUTERN ONTARIO AND QUEBEC THURSDAY AFTERNOON/EVENING. A FEW N GALE
FORCE GUSTS TO 35KTS WILL BE POSSIBLE THURSDAY AFTERNOON ACROSS
MAINLY CENTRAL LAKE SUPERIOR...WITH HEAVY FREEZING SPRAY OVER MUCH
OF THE LAKE THURSDAY NIGHT. WHILE A WEAKENING TROUGH OF LOW PRESSURE
REMAINS OVER EASTERN LAKE SUPERIOR...HIGH PRESSURE WILL SLOWLY BUILD
IN FROM THE WEST THORUGH SATURDAY.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
GALE WARNING UNTIL 10 PM EST THIS EVENING FOR LSZ248>250-265-266.
GALE WARNING UNTIL 7 PM EST THIS EVENING FOR LSZ264.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...VOSS
LONG TERM...KF
AVIATION...VOSS
MARINE...VOSS/KF
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
138 PM EST MON FEB 11 2013
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 525 AM EST MON FEB 11 2013
PER WATER VAPOR IMAGERY AND RUC ANALYSIS...MID LEVEL LOW IS
CURRENTLY SPINNING EASTWARD OVER NRN WI ATTM. ASSOCIATED SFC LOW
APPEARS TO BE NEARING THE AREA BTWN WATERSMEET AND IRON RIVER. WHILE
MAIN BAND OF WAA/ISENTROPIC ASCENT PCPN HAS PUSHED WELL N AND E OF
THE AREA...REGIONAL RADAR IMAGERY SHOWS AREAS OF MOSTLY LIGHT PCPN
CIRCULATING AROUND THE MID LEVEL LOW. AHEAD OF THE LOW...LOW-LEVELS
HAVE WARMED SUFFICIENTLY OVER ROUGHLY THE E HALF OF UPPER MI TO
RESULT IN PTYPE BEING JUST RAIN EARLY THIS MORNING (SFC TEMPS HAVE
EVEN RISEN TO THE MID/UPPER 30S). PCPN TRANSITIONS BACK TO SNOW OVER
WRN UPPER MI AND NW WI.
OVER THE NEXT SEVERAL HRS...COLUMN WILL COOL AS MID LEVEL LOW TRACKS
EASTWARD. AS A RESULT...WHERE PCPN IS NOW RAIN...IT WILL CHANGE BACK
TO ALL SNOW DURING THE MORNING. ATTENTION THEN TURNS TO POTENTIAL
LAKE ENHANCEMENT TODAY. IT WON`T BE THE TYPICAL LAKE ENHANCED EVENT
PRODUCING MDT/HVY SNOW THAT WOULD NORMALLY BE EXPECTED AT THIS TIME
OF YEAR BECAUSE THE AIR MASS IS MILD ACROSS THE AREA RIGHT NOW
(850MB TEMPS ARE -1 TO -5C OVER LAKE SUPERIOR). SO INITIALLY...EVEN
AS WINDS INCREASE OUT OF THE N TO NW BEHIND SFC LOW...AIR MASS WILL
BE TOO WARM FOR LAKE ENHANCEMENT THOUGH THERE WILL BE SOME TERRAIN
ENHANCEMENT FROM THE UPSLOPING FLOW. OVER THE W...THERE WILL BE A
WINDOW FOR LAKE ENHANCEMENT FROM LATE MORNING INTO THE AFTN AS 850MB
TEMPS FALL BLO -7C. INTO NCNTRL UPPER MI...WINDOW LOOKS SHORTER LATE
THIS AFTN/EVENING. THUS...PROBABLY SHOULDN`T SEE MUCH MORE THAN 2-4
INCHES OF SNOW OVER THE W TODAY. BEHIND THE SFC LOW...WINDS MORE
QUICKLY BACK NW ACROSS NCNTRL UPPER MI WHICH WILL LIMIT LAKE
ENHANCEMENT AND MORE QUICKLY DIMINISH TERRAIN ENHANCEMENT INTO
MARQUETTE COUNTY. CONSIDERED DROPPING ADVY FOR MARQUETTE COUNTY...
BUT WILL WAIT TO SEE HOW THINGS EVOLVE DURING THE MORNING OVER THE W
TO GET AN IDEA OF HOW ENHANCEMENT WILL PLAY OUT OVER THE NCNTRL.
IT`S POSSIBLE AN ADVY MAY BE NEEDED TO THE E OF MARQUETTE LATER THIS
AFTN/EVENING...BUT EXPECTATION IS THAT SNOW ACCUMULATIONS WILL BE
UNDER ADVY AMOUNTS. PERIOD OF GUSTY N/NW WINDS TO 30-35MPH ALONG
LAKE SUPERIOR NW AND NCNTRL WILL LEAD TO SOME BLSN THIS AFTN/EVENING.
AS FOR HEADLINES...CANCELLED ADVY FOR MENOMINEE/DELTA/ALGER EASTWARD
AS TEMPS HAVE RISEN TO THE MID/UPPER 30S WITH ONLY RAIN FALLING.
REMAINING ADVYS WERE NOT CHANGED.
AS DEEPER MOISTURE EXITS TONIGHT...SNOW NEAR LAKE SUPERIOR SHOULD
STEADILY DIMINISH W TO E (POSSIBLY EVEN END) AS 850MB TEMPS WILL BE
MARGINAL AROUND THE THRESHOLD FOR LES.
.LONG TERM...(TUESDAY THROUGH SUNDAY)
ISSUED AT 424 AM EST MON FEB 11 2013
LINGERING LIGHT LAKE EFFECT IS EXPECTED FOR THE START OF THE LONG
TERM PERIOD. BUT INCREASED DRYING FROM WEST TO EAST...WARMING
850MB TEMPS AND WINDS BACKING TO THE SOUTHWEST WITH THE
SURFACE RIDGE MOVING ACROSS THE REGION ON TUESDAY WILL LEAD QUICKLY
DIMINISHING LAKE EFFECT SNOW DURING THE DAY TUESDAY. CLOUDS WILL
ALSO BE ON THE DECREASE THROUGH THE DAY AND GOING FORECAST HAS A
DECENT TREND ON THAT IDEA.
THE HIGH PRESSURE RIDGE QUICKLY SLIDES EAST ON TUESDAY
AFTERNOON/EVENING AND AREA COMES UNDER THE INFLUENCE OF SEVERAL
NORTHERN STREAM WAVES FOR THE REST OF THE WORK WEEK. THE FIRST
WAVE...NEAR LAKE WINNIPEG AT 00Z WED...WILL DIVE SOUTHEAST ACROSS
LAKE SUPERIOR ON WEDNESDAY. BEST DEEP MOISTURE LOOKS TO STAY OVER
THE NORTHEAST HALF OF THE LAKE AND WITH GENERALLY WESTERLY FLOW
ACROSS THE CWA...DON/T EXPECT MUCH FOR PRECIPITATION CHANCES ON
WEDNESDAY EVEN THOUGH THE BROAD SURFACE TROUGH MOVES THROUGH.
THE NEXT SHORTWAVE...TRACKING FARTHER TO THE SOUTHEAST...WILL
DEPART ALBERTA ON WEDNESDAY AND MOVE INTO THE NORTHERN PLAINS ON
WEDNESDAY EVENING AND THEN TRACK INTO THE WESTERN GREAT LAKES FOR
THURSDAY. STILL SOME DIFFERENCES IN THE DETERMINISTIC MODELS AND
ENSEMBLE MEMBERS FROM THE GFS/GEM/ECMWF WITH THE STRENGTH OF THIS
SHORTWAVE AND THE RESULTING STRENGTH/LOCATION OF THE ASSOCIATED
SURFACE LOW. HPC PREFERS A BLEND OF THE 18Z GFES AND 12Z ECMWF ENS
MEAN AND THAT SEEMS LIKE A DECENT COMPROMISE. THIS WOULD SWEEP THE
SHORTWAVE THROUGH WISCONSIN ON THURSDAY AND HAVE A LOW 1000S MB LOW
MOVING THROUGH NORTHERN WISCONSIN OR SOUTHERN UPPER MICHIGAN. AT
THIS POINT...WOULD JUST EXPECT A DUSTING TO A COUPLE INCHES OF SNOW
WITH THIS SYSTEM...UNLESS THE STRONGER GFS SOLUTION IS CORRECT
WHICH WOULD PRODUCE ADVISORY SNOWFALL.
ANOTHER SHORTWAVE DIVING SSE ON THE BACK SIDE OF THE THURSDAY
SHORTWAVE WILL AMPLIFY THE UPPER TROUGH FURTHER AND LEAD TO IT
MERGING WITH THE SOUTHERN STREAM FOR FRIDAY AND THE WEEKEND...WHILE
AN UPPER RIDGE BUILDS OVER THE WRN CONUS. THIS WILL ALLOW COLDER AIR
TO SPILL SOUTH ACROSS THE UPPER GREAT LAKES REGION AND PRODUCE A
PERIOD OF BELOW NORMAL TEMPERATURES THROUGH THE WEEKEND. WITH THIS
COLDER AIR...ALSO EXPECT THE AREA TO SEE LAKE EFFECT SNOW DUE TO
850MB TEMPS FALLING TOWARDS -21C BY SATURDAY. WITH A HIGH PRESSURE
RIDGE EXPECTED TO BUILD INTO THE NORTHERN PLAINS DURING THIS
TIME...WIND DIRECTIONS WILL DEPEND ON IF A LOW DEVELOPS AND MOVES UP
THE ATLANTIC SEABOARD /ECMWF-YES AND GFS-MAYBE/. IF IT DOES
OCCUR...WOULD EXPECT MORE N-NNW WIND LAKE EFFECT...WHILE NW LAKE
EFFECT WOULD BE EXPECTED WITHOUT THE LOW. SINCE MODELS ARE MORE
CONSISTENT ON LAKE EFFECT POTENTIAL FOR FRIDAY AND THE
WEEKEND...WILL CONTINUE TO TREND POPS UP. A LITTLE TOO EARLY TO PIN
DOWN TIMING/LOCATION FOR LIKELY POPS...BUT THERE APPEARS TO BE
SEVERAL WEAK WAVES MOVING THROUGH THAT WILL INCREASE MOISTURE AND
INTENSIFY THE LAKE EFFECT.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z TUESDAY AFTERNOON)
ISSUED AT 125 PM EST MON FEB 11 2013
IFR CONDITIONS WITH LAKE ENHANCED -SN SHOULD PREVAIL AT
KIWD/KCMX/KSAW THIS AFTERNOON UNDER GUSTY NNW WINDS ON BACKSIDE OF
LOW PRES SYSTEM MOVING EAST OF LAKE SUPEPIOR. MID TO LATE
AFTERNOON...IMPROVEMENT INTO THE MVFR RANGE IS EXPECTED AS THE STORM
SYSTEM CONTINUES TO MOVE EAST. MVFR CIGS MAY SCATTER OUT LATE
TONIGHT AT KIWD AS WINDS BACK TOWARD THE SW...AND PERHAPS AT KSAW
UNDER DOWNSLOPING W TO NW WINDS. LOOK FOR MVFR CIGS TO SCT OUT AT
BOTH KCMX AND KSAW BY LATE TUE MORNING WITH INCREASED SUBSIDENCE AND
RDGG.
&&
.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 525 AM EST MON FEB 11 2013
ON THE BACKSIDE OF LOW PRES MOVING ACROSS UPPER MI/ERN LAKE SUPERIOR
TODAY...EXPECT A PERIOD OF N TO NW GALES TO DEVELOP FROM NW TO SE
DURING THE DAY. APPROACHING HIGH PRES RIDGE WILL THEN CAUSE WINDS TO
DIMINISH TO UNDER 25 KTS TONIGHT. WINDS WILL BECOME W-SW TUE/TUE
NIGHT AS THE RIDGE SHIFTS TO THE E. THE W-SW FLOW WILL BE STRONGEST
BTWN THE KEWEENAW AND ISLE ROYALE (POSSIBLY 20-30KT). LIGHTER WINDS
UNDER 20KT SHOULD THEN PREVAIL LATER TUE NIGHT THRU WED NIGHT UNDER
WEAKER PRES GRADIENT. LOW PRES WILL MOVE ACROSS THE WRN LAKES THU.
BEHIND THE LOW...NORTHERLY WINDS WILL INCREASE INTO THE 15-30KT
RANGE...STRONGEST OVER CNTRL/ERN LAKE SUPERIOR. FREEZING SPRAY WILL
ALSO RETURN AS ARCTIC AIR FLOWS BACK INTO THE UPPER LAKES.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
WINTER WEATHER ADVISORY UNTIL 1 AM EST /MIDNIGHT CST/ TUESDAY
FOR MIZ001>003-009.
WINTER WEATHER ADVISORY UNTIL 7 PM EST THIS EVENING FOR MIZ004-
005-084.
LAKE SUPERIOR...
GALE WARNING UNTIL 10 PM EST THIS EVENING FOR LSZ248>250-265-266.
GALE WARNING UNTIL 7 PM EST THIS EVENING FOR LSZ264.
GALE WARNING UNTIL 4 PM EST THIS AFTERNOON FOR LSZ263.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...ROLFSON
LONG TERM...SRF
AVIATION...VOSS
MARINE...ROLFSON
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
653 AM EST MON FEB 11 2013
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 525 AM EST MON FEB 11 2013
PER WATER VAPOR IMAGERY AND RUC ANALYSIS...MID LEVEL LOW IS
CURRENTLY SPINNING EASTWARD OVER NRN WI ATTM. ASSOCIATED SFC LOW
APPEARS TO BE NEARING THE AREA BTWN WATERSMEET AND IRON RIVER. WHILE
MAIN BAND OF WAA/ISENTROPIC ASCENT PCPN HAS PUSHED WELL N AND E OF
THE AREA...REGIONAL RADAR IMAGERY SHOWS AREAS OF MOSTLY LIGHT PCPN
CIRCULATING AROUND THE MID LEVEL LOW. AHEAD OF THE LOW...LOW-LEVELS
HAVE WARMED SUFFICIENTLY OVER ROUGHLY THE E HALF OF UPPER MI TO
RESULT IN PTYPE BEING JUST RAIN EARLY THIS MORNING (SFC TEMPS HAVE
EVEN RISEN TO THE MID/UPPER 30S). PCPN TRANSITIONS BACK TO SNOW OVER
WRN UPPER MI AND NW WI.
OVER THE NEXT SEVERAL HRS...COLUMN WILL COOL AS MID LEVEL LOW TRACKS
EASTWARD. AS A RESULT...WHERE PCPN IS NOW RAIN...IT WILL CHANGE BACK
TO ALL SNOW DURING THE MORNING. ATTENTION THEN TURNS TO POTENTIAL
LAKE ENHANCEMENT TODAY. IT WON`T BE THE TYPICAL LAKE ENHANCED EVENT
PRODUCING MDT/HVY SNOW THAT WOULD NORMALLY BE EXPECTED AT THIS TIME
OF YEAR BECAUSE THE AIR MASS IS MILD ACROSS THE AREA RIGHT NOW
(850MB TEMPS ARE -1 TO -5C OVER LAKE SUPERIOR). SO INITIALLY...EVEN
AS WINDS INCREASE OUT OF THE N TO NW BEHIND SFC LOW...AIR MASS WILL
BE TOO WARM FOR LAKE ENHANCEMENT THOUGH THERE WILL BE SOME TERRAIN
ENHANCEMENT FROM THE UPSLOPING FLOW. OVER THE W...THERE WILL BE A
WINDOW FOR LAKE ENHANCEMENT FROM LATE MORNING INTO THE AFTN AS 850MB
TEMPS FALL BLO -7C. INTO NCNTRL UPPER MI...WINDOW LOOKS SHORTER LATE
THIS AFTN/EVENING. THUS...PROBABLY SHOULDN`T SEE MUCH MORE THAN 2-4
INCHES OF SNOW OVER THE W TODAY. BEHIND THE SFC LOW...WINDS MORE
QUICKLY BACK NW ACROSS NCNTRL UPPER MI WHICH WILL LIMIT LAKE
ENHANCEMENT AND MORE QUICKLY DIMINISH TERRAIN ENHANCEMENT INTO
MARQUETTE COUNTY. CONSIDERED DROPPING ADVY FOR MARQUETTE COUNTY...
BUT WILL WAIT TO SEE HOW THINGS EVOLVE DURING THE MORNING OVER THE W
TO GET AN IDEA OF HOW ENHANCEMENT WILL PLAY OUT OVER THE NCNTRL.
IT`S POSSIBLE AN ADVY MAY BE NEEDED TO THE E OF MARQUETTE LATER THIS
AFTN/EVENING...BUT EXPECTATION IS THAT SNOW ACCUMULATIONS WILL BE
UNDER ADVY AMOUNTS. PERIOD OF GUSTY N/NW WINDS TO 30-35MPH ALONG
LAKE SUPERIOR NW AND NCNTRL WILL LEAD TO SOME BLSN THIS AFTN/EVENING.
AS FOR HEADLINES...CANCELLED ADVY FOR MENOMINEE/DELTA/ALGER EASTWARD
AS TEMPS HAVE RISEN TO THE MID/UPPER 30S WITH ONLY RAIN FALLING.
REMAINING ADVYS WERE NOT CHANGED.
AS DEEPER MOISTURE EXITS TONIGHT...SNOW NEAR LAKE SUPERIOR SHOULD
STEADILY DIMINISH W TO E (POSSIBLY EVEN END) AS 850MB TEMPS WILL BE
MARGINAL AROUND THE THRESHOLD FOR LES.
.LONG TERM...(TUESDAY THROUGH SUNDAY)
ISSUED AT 424 AM EST MON FEB 11 2013
LINGERING LIGHT LAKE EFFECT IS EXPECTED FOR THE START OF THE LONG
TERM PERIOD. BUT INCREASED DRYING FROM WEST TO EAST...WARMING
850MB TEMPS AND WINDS BACKING TO THE SOUTHWEST WITH THE
SURFACE RIDGE MOVING ACROSS THE REGION ON TUESDAY WILL LEAD QUICKLY
DIMINISHING LAKE EFFECT SNOW DURING THE DAY TUESDAY. CLOUDS WILL
ALSO BE ON THE DECREASE THROUGH THE DAY AND GOING FORECAST HAS A
DECENT TREND ON THAT IDEA.
THE HIGH PRESSURE RIDGE QUICKLY SLIDES EAST ON TUESDAY
AFTERNOON/EVENING AND AREA COMES UNDER THE INFLUENCE OF SEVERAL
NORTHERN STREAM WAVES FOR THE REST OF THE WORK WEEK. THE FIRST
WAVE...NEAR LAKE WINNIPEG AT 00Z WED...WILL DIVE SOUTHEAST ACROSS
LAKE SUPERIOR ON WEDNESDAY. BEST DEEP MOISTURE LOOKS TO STAY OVER
THE NORTHEAST HALF OF THE LAKE AND WITH GENERALLY WESTERLY FLOW
ACROSS THE CWA...DON/T EXPECT MUCH FOR PRECIPITATION CHANCES ON
WEDNESDAY EVEN THOUGH THE BROAD SURFACE TROUGH MOVES THROUGH.
THE NEXT SHORTWAVE...TRACKING FARTHER TO THE SOUTHEAST...WILL
DEPART ALBERTA ON WEDNESDAY AND MOVE INTO THE NORTHERN PLAINS ON
WEDNESDAY EVENING AND THEN TRACK INTO THE WESTERN GREAT LAKES FOR
THURSDAY. STILL SOME DIFFERENCES IN THE DETERMINISTIC MODELS AND
ENSEMBLE MEMBERS FROM THE GFS/GEM/ECMWF WITH THE STRENGTH OF THIS
SHORTWAVE AND THE RESULTING STRENGTH/LOCATION OF THE ASSOCIATED
SURFACE LOW. HPC PREFERS A BLEND OF THE 18Z GFES AND 12Z ECMWF ENS
MEAN AND THAT SEEMS LIKE A DECENT COMPROMISE. THIS WOULD SWEEP THE
SHORTWAVE THROUGH WISCONSIN ON THURSDAY AND HAVE A LOW 1000S MB LOW
MOVING THROUGH NORTHERN WISCONSIN OR SOUTHERN UPPER MICHIGAN. AT
THIS POINT...WOULD JUST EXPECT A DUSTING TO A COUPLE INCHES OF SNOW
WITH THIS SYSTEM...UNLESS THE STRONGER GFS SOLUTION IS CORRECT
WHICH WOULD PRODUCE ADVISORY SNOWFALL.
ANOTHER SHORTWAVE DIVING SSE ON THE BACK SIDE OF THE THURSDAY
SHORTWAVE WILL AMPLIFY THE UPPER TROUGH FURTHER AND LEAD TO IT
MERGING WITH THE SOUTHERN STREAM FOR FRIDAY AND THE WEEKEND...WHILE
AN UPPER RIDGE BUILDS OVER THE WRN CONUS. THIS WILL ALLOW COLDER AIR
TO SPILL SOUTH ACROSS THE UPPER GREAT LAKES REGION AND PRODUCE A
PERIOD OF BELOW NORMAL TEMPERATURES THROUGH THE WEEKEND. WITH THIS
COLDER AIR...ALSO EXPECT THE AREA TO SEE LAKE EFFECT SNOW DUE TO
850MB TEMPS FALLING TOWARDS -21C BY SATURDAY. WITH A HIGH PRESSURE
RIDGE EXPECTED TO BUILD INTO THE NORTHERN PLAINS DURING THIS
TIME...WIND DIRECTIONS WILL DEPEND ON IF A LOW DEVELOPS AND MOVES UP
THE ATLANTIC SEABOARD /ECMWF-YES AND GFS-MAYBE/. IF IT DOES
OCCUR...WOULD EXPECT MORE N-NNW WIND LAKE EFFECT...WHILE NW LAKE
EFFECT WOULD BE EXPECTED WITHOUT THE LOW. SINCE MODELS ARE MORE
CONSISTENT ON LAKE EFFECT POTENTIAL FOR FRIDAY AND THE
WEEKEND...WILL CONTINUE TO TREND POPS UP. A LITTLE TOO EARLY TO PIN
DOWN TIMING/LOCATION FOR LIKELY POPS...BUT THERE APPEARS TO BE
SEVERAL WEAK WAVES MOVING THROUGH THAT WILL INCREASE MOISTURE AND
INTENSIFY THE LAKE EFFECT.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z TUESDAY MORNING)
ISSUED AT 652 AM EST MON FEB 11 2013
LIFR/IFR CONDITIONS WITH -SN WILL PREVAIL AT KIWD/KCMX/KSAW THROUGH
THE MORNING HRS AS A LOW PRES SYSTEM MOVES ACROSS UPPER MI. IN THE
WAKE OF THE LOW...EXPECT STRONGER N TO NW WINDS TO DEVELOP FROM W TO
E THIS MORNING/EARLY AFTN. GUSTS SHOULD BE IN THE 20-30KT RANGE.
MID TO LATE AFTERNOON...IMPROVEMENT INTO THE MVFR RANGE IS EXPECTED
AS THE STORM SYSTEM MOVES OFF TO THE EAST. MVFR CIGS MAY SCATTER OUT
LATE TONIGHT AT KIWD AS WINDS BACK TOWARD THE SW...AND PERHAPS AT
KSAW UNDER DOWNSLOPING W TO NW WINDS.
&&
.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 525 AM EST MON FEB 11 2013
ON THE BACKSIDE OF LOW PRES MOVING ACROSS UPPER MI/ERN LAKE SUPERIOR
TODAY...EXPECT A PERIOD OF N TO NW GALES TO DEVELOP FROM NW TO SE
DURING THE DAY. APPROACHING HIGH PRES RIDGE WILL THEN CAUSE WINDS TO
DIMINISH TO UNDER 25 KTS TONIGHT. WINDS WILL BECOME W-SW TUE/TUE
NIGHT AS THE RIDGE SHIFTS TO THE E. THE W-SW FLOW WILL BE STRONGEST
BTWN THE KEWEENAW AND ISLE ROYALE (POSSIBLY 20-30KT). LIGHTER WINDS
UNDER 20KT SHOULD THEN PREVAIL LATER TUE NIGHT THRU WED NIGHT UNDER
WEAKER PRES GRADIENT. LOW PRES WILL MOVE ACROSS THE WRN LAKES THU.
BEHIND THE LOW...NORTHERLY WINDS WILL INCREASE INTO THE 15-30KT
RANGE...STRONGEST OVER CNTRL/ERN LAKE SUPERIOR. FREEZING SPRAY WILL
ALSO RETURN AS ARCTIC AIR FLOWS BACK INTO THE UPPER LAKES.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
WINTER WEATHER ADVISORY UNTIL 1 AM EST /MIDNIGHT CST/ TUESDAY
FOR MIZ001>003-009.
WINTER WEATHER ADVISORY UNTIL 10 AM CST THIS MORNING FOR MIZ010-
011.
WINTER WEATHER ADVISORY UNTIL 7 PM EST THIS EVENING FOR MIZ004-
005-084.
LAKE SUPERIOR...
GALE WARNING FROM 1 PM THIS AFTERNOON TO 10 PM EST THIS EVENING
FOR LSZ248>250-265-266.
GALE WARNING UNTIL 10 AM EST /9 AM CST/ THIS MORNING FOR LSZ162.
GALE WARNING UNTIL 7 PM EST THIS EVENING FOR LSZ264.
GALE WARNING UNTIL 4 PM EST THIS AFTERNOON FOR LSZ263.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...ROLFSON
LONG TERM...SRF
AVIATION...ROLFSON
MARINE...ROLFSON
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
526 AM EST MON FEB 11 2013
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 525 AM EST MON FEB 11 2013
PER WATER VAPOR IMAGERY AND RUC ANALYSIS...MID LEVEL LOW IS
CURRENTLY SPINNING EASTWARD OVER NRN WI ATTM. ASSOCIATED SFC LOW
APPEARS TO BE NEARING THE AREA BTWN WATERSMEET AND IRON RIVER. WHILE
MAIN BAND OF WAA/ISENTROPIC ASCENT PCPN HAS PUSHED WELL N AND E OF
THE AREA...REGIONAL RADAR IMAGERY SHOWS AREAS OF MOSTLY LIGHT PCPN
CIRCULATING AROUND THE MID LEVEL LOW. AHEAD OF THE LOW...LOW-LEVELS
HAVE WARMED SUFFICIENTLY OVER ROUGHLY THE E HALF OF UPPER MI TO
RESULT IN PTYPE BEING JUST RAIN EARLY THIS MORNING (SFC TEMPS HAVE
EVEN RISEN TO THE MID/UPPER 30S). PCPN TRANSITIONS BACK TO SNOW OVER
WRN UPPER MI AND NW WI.
OVER THE NEXT SEVERAL HRS...COLUMN WILL COOL AS MID LEVEL LOW TRACKS
EASTWARD. AS A RESULT...WHERE PCPN IS NOW RAIN...IT WILL CHANGE BACK
TO ALL SNOW DURING THE MORNING. ATTENTION THEN TURNS TO POTENTIAL
LAKE ENHANCEMENT TODAY. IT WON`T BE THE TYPICAL LAKE ENHANCED EVENT
PRODUCING MDT/HVY SNOW THAT WOULD NORMALLY BE EXPECTED AT THIS TIME
OF YEAR BECAUSE THE AIR MASS IS MILD ACROSS THE AREA RIGHT NOW
(850MB TEMPS ARE -1 TO -5C OVER LAKE SUPERIOR). SO INITIALLY...EVEN
AS WINDS INCREASE OUT OF THE N TO NW BEHIND SFC LOW...AIR MASS WILL
BE TOO WARM FOR LAKE ENHANCEMENT THOUGH THERE WILL BE SOME TERRAIN
ENHANCEMENT FROM THE UPSLOPING FLOW. OVER THE W...THERE WILL BE A
WINDOW FOR LAKE ENHANCEMENT FROM LATE MORNING INTO THE AFTN AS 850MB
TEMPS FALL BLO -7C. INTO NCNTRL UPPER MI...WINDOW LOOKS SHORTER LATE
THIS AFTN/EVENING. THUS...PROBABLY SHOULDN`T SEE MUCH MORE THAN 2-4
INCHES OF SNOW OVER THE W TODAY. BEHIND THE SFC LOW...WINDS MORE
QUICKLY BACK NW ACROSS NCNTRL UPPER MI WHICH WILL LIMIT LAKE
ENHANCEMENT AND MORE QUICKLY DIMINISH TERRAIN ENHANCEMENT INTO
MARQUETTE COUNTY. CONSIDERED DROPPING ADVY FOR MARQUETTE COUNTY...
BUT WILL WAIT TO SEE HOW THINGS EVOLVE DURING THE MORNING OVER THE W
TO GET AN IDEA OF HOW ENHANCEMENT WILL PLAY OUT OVER THE NCNTRL.
IT`S POSSIBLE AN ADVY MAY BE NEEDED TO THE E OF MARQUETTE LATER THIS
AFTN/EVENING...BUT EXPECTATION IS THAT SNOW ACCUMULATIONS WILL BE
UNDER ADVY AMOUNTS. PERIOD OF GUSTY N/NW WINDS TO 30-35MPH ALONG
LAKE SUPERIOR NW AND NCNTRL WILL LEAD TO SOME BLSN THIS AFTN/EVENING.
AS FOR HEADLINES...CANCELLED ADVY FOR MENOMINEE/DELTA/ALGER EASTWARD
AS TEMPS HAVE RISEN TO THE MID/UPPER 30S WITH ONLY RAIN FALLING.
REMAINING ADVYS WERE NOT CHANGED.
AS DEEPER MOISTURE EXITS TONIGHT...SNOW NEAR LAKE SUPERIOR SHOULD
STEADILY DIMINISH W TO E (POSSIBLY EVEN END) AS 850MB TEMPS WILL BE
MARGINAL AROUND THE THRESHOLD FOR LES.
.LONG TERM...(TUESDAY THROUGH SUNDAY)
ISSUED AT 424 AM EST MON FEB 11 2013
LINGERING LIGHT LAKE EFFECT IS EXPECTED FOR THE START OF THE LONG
TERM PERIOD. BUT INCREASED DRYING FROM WEST TO EAST...WARMING
850MB TEMPS AND WINDS BACKING TO THE SOUTHWEST WITH THE
SURFACE RIDGE MOVING ACROSS THE REGION ON TUESDAY WILL LEAD QUICKLY
DIMINISHING LAKE EFFECT SNOW DURING THE DAY TUESDAY. CLOUDS WILL
ALSO BE ON THE DECREASE THROUGH THE DAY AND GOING FORECAST HAS A
DECENT TREND ON THAT IDEA.
THE HIGH PRESSURE RIDGE QUICKLY SLIDES EAST ON TUESDAY
AFTERNOON/EVENING AND AREA COMES UNDER THE INFLUENCE OF SEVERAL
NORTHERN STREAM WAVES FOR THE REST OF THE WORK WEEK. THE FIRST
WAVE...NEAR LAKE WINNIPEG AT 00Z WED...WILL DIVE SOUTHEAST ACROSS
LAKE SUPERIOR ON WEDNESDAY. BEST DEEP MOISTURE LOOKS TO STAY OVER
THE NORTHEAST HALF OF THE LAKE AND WITH GENERALLY WESTERLY FLOW
ACROSS THE CWA...DON/T EXPECT MUCH FOR PRECIPITATION CHANCES ON
WEDNESDAY EVEN THOUGH THE BROAD SURFACE TROUGH MOVES THROUGH.
THE NEXT SHORTWAVE...TRACKING FARTHER TO THE SOUTHEAST...WILL
DEPART ALBERTA ON WEDNESDAY AND MOVE INTO THE NORTHERN PLAINS ON
WEDNESDAY EVENING AND THEN TRACK INTO THE WESTERN GREAT LAKES FOR
THURSDAY. STILL SOME DIFFERENCES IN THE DETERMINISTIC MODELS AND
ENSEMBLE MEMBERS FROM THE GFS/GEM/ECMWF WITH THE STRENGTH OF THIS
SHORTWAVE AND THE RESULTING STRENGTH/LOCATION OF THE ASSOCIATED
SURFACE LOW. HPC PREFERS A BLEND OF THE 18Z GFES AND 12Z ECMWF ENS
MEAN AND THAT SEEMS LIKE A DECENT COMPROMISE. THIS WOULD SWEEP THE
SHORTWAVE THROUGH WISCONSIN ON THURSDAY AND HAVE A LOW 1000S MB LOW
MOVING THROUGH NORTHERN WISCONSIN OR SOUTHERN UPPER MICHIGAN. AT
THIS POINT...WOULD JUST EXPECT A DUSTING TO A COUPLE INCHES OF SNOW
WITH THIS SYSTEM...UNLESS THE STRONGER GFS SOLUTION IS CORRECT
WHICH WOULD PRODUCE ADVISORY SNOWFALL.
ANOTHER SHORTWAVE DIVING SSE ON THE BACK SIDE OF THE THURSDAY
SHORTWAVE WILL AMPLIFY THE UPPER TROUGH FURTHER AND LEAD TO IT
MERGING WITH THE SOUTHERN STREAM FOR FRIDAY AND THE WEEKEND...WHILE
AN UPPER RIDGE BUILDS OVER THE WRN CONUS. THIS WILL ALLOW COLDER AIR
TO SPILL SOUTH ACROSS THE UPPER GREAT LAKES REGION AND PRODUCE A
PERIOD OF BELOW NORMAL TEMPERATURES THROUGH THE WEEKEND. WITH THIS
COLDER AIR...ALSO EXPECT THE AREA TO SEE LAKE EFFECT SNOW DUE TO
850MB TEMPS FALLING TOWARDS -21C BY SATURDAY. WITH A HIGH PRESSURE
RIDGE EXPECTED TO BUILD INTO THE NORTHERN PLAINS DURING THIS
TIME...WIND DIRECTIONS WILL DEPEND ON IF A LOW DEVELOPS AND MOVES UP
THE ATLANTIC SEABOARD /ECMWF-YES AND GFS-MAYBE/. IF IT DOES
OCCUR...WOULD EXPECT MORE N-NNW WIND LAKE EFFECT...WHILE NW LAKE
EFFECT WOULD BE EXPECTED WITHOUT THE LOW. SINCE MODELS ARE MORE
CONSISTENT ON LAKE EFFECT POTENTIAL FOR FRIDAY AND THE
WEEKEND...WILL CONTINUE TO TREND POPS UP. A LITTLE TOO EARLY TO PIN
DOWN TIMING/LOCATION FOR LIKELY POPS...BUT THERE APPEARS TO BE
SEVERAL WEAK WAVES MOVING THROUGH THAT WILL INCREASE MOISTURE AND
INTENSIFY THE LAKE EFFECT.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z MONDAY NIGHT)
ISSUED AT 1208 AM EST MON FEB 11 2013
EXPECT PREDOMINANT IFR WITH OCNL LIFR CONDITIONS OVERNIGHT WITH
PERIODS OF LIGHT SNOW. VLIFR FOG AT CMX IS EXPECTED TO IMPROVE AS
WINDS BACK TO THE NORTHEAST. WITH WINDS BECOMING NORTH TODAY...A
PERIOD OF LAKE ENHANCED SNOW WILL HELP KEEP VSBY IN THE IFR RANGE.
BY MID TO LATE AFTERNOON...IMPROVEMENT INTO THE MVFR RANGE IS
EXPECTED AS THE STORM SYSTEM MOVES OFF TO THE NORTHEAST.
&&
.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 525 AM EST MON FEB 11 2013
ON THE BACKSIDE OF LOW PRES MOVING ACROSS UPPER MI/ERN LAKE SUPERIOR
TODAY...EXPECT A PERIOD OF N TO NW GALES TO DEVELOP FROM NW TO SE
DURING THE DAY. APPROACHING HIGH PRES RIDGE WILL THEN CAUSE WINDS TO
DIMINISH TO UNDER 25 KTS TONIGHT. WINDS WILL BECOME W-SW TUE/TUE
NIGHT AS THE RIDGE SHIFTS TO THE E. THE W-SW FLOW WILL BE STRONGEST
BTWN THE KEWEENAW AND ISLE ROYALE (POSSIBLY 20-30KT). LIGHTER WINDS
UNDER 20KT SHOULD THEN PREVAIL LATER TUE NIGHT THRU WED NIGHT UNDER
WEAKER PRES GRADIENT. LOW PRES WILL MOVE ACROSS THE WRN LAKES THU.
BEHIND THE LOW...NORTHERLY WINDS WILL INCREASE INTO THE 15-30KT
RANGE...STRONGEST OVER CNTRL/ERN LAKE SUPERIOR. FREEZING SPRAY WILL
ALSO RETURN AS ARCTIC AIR FLOWS BACK INTO THE UPPER LAKES.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
WINTER WEATHER ADVISORY UNTIL 1 AM EST /MIDNIGHT CST/ TUESDAY
FOR MIZ001>003-009.
WINTER WEATHER ADVISORY UNTIL 10 AM CST THIS MORNING FOR MIZ010-
011.
WINTER WEATHER ADVISORY UNTIL 7 PM EST THIS EVENING FOR MIZ004-
005-084.
LAKE SUPERIOR...
GALE WARNING FROM 1 PM THIS AFTERNOON TO 10 PM EST THIS EVENING
FOR LSZ248>250-265-266.
GALE WARNING UNTIL 10 AM EST /9 AM CST/ THIS MORNING FOR LSZ162.
GALE WARNING UNTIL 7 PM EST THIS EVENING FOR LSZ264.
GALE WARNING UNTIL 4 PM EST THIS AFTERNOON FOR LSZ263.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...ROLFSON
LONG TERM...SRF
AVIATION...JLB
MARINE...ROLFSON
AREA FORECAST DISCUSSION
NWS DULUTH MN
1136 PM CST SUN FEB 10 2013
.AVIATION...06Z TAFS
A MIXTURE OF IFR AND MVFR CONDITIONS COVERED THE NORTHLAND IN
AREAS OF LIGHT SNOW...WITH AREAS OF FREEZING DRIZZLE ALSO
OCCURRING. THE FREEZING DRIZZLE WAS FALLING MAINLY OVER SOUTHERN
AREAS. THE PRECIPITATION SHOULD DIMINISH IN INTENSITY LATE TONIGHT
OR MONDAY MORNING FOR MOST AREAS. VSBYS WILL RISE AS THE PRECIP
INTENSITY DIMINISHES...AND CEILINGS WILL INCREASE THROUGH THE DAY
AS WELL. CEILINGS MAY RISE TO OR SCATTER OUT AND BECOME VFR LATE
IN THE PERIOD...MAINLY OVER WESTERN TAF SITES.
&&
.PREV DISCUSSION... /ISSUED 938 PM CST SUN FEB 10 2013/
UPDATE...
PRECIPITATION RATES HAVE DIMINISHED THIS EVENING FOR MUCH OF THE
NORTHLAND...AND AS THAT HAS HAPPENED MORE FREEZING DRIZZLE HAS
DEVELOPED. AN AREA OF HEAVIER PRECIPITATION WAS ROTATING NORTH
TOWARD PRICE/SAWYER/WASHBURN COUNTIES AND MOST OBSERVATIONS UNDER
THIS PRECIP HAS BEEN RAIN. GIVEN SURFACE TEMPS AND ROAD TEMPS ARE
LIKELY AT OR BELOW FREEZING OVER MUCH OF THAT AREA...WE ADDED
FREEZING RAIN TO THE FORECAST.
THE HEAVY SNOW BAND WAS ROTATING THROUGH OUR EXTREME NORTH
CENTRAL/NORTHWEST ZONES AS OF 930 PM...AND PRECIP RATES THERE
SHOULD DIMINISH LATER THIS EVENING.
WE KEPT ALL THE WARNINGS GOING...BUT DID MAKE SOME CHANGES TO THE
EXPIRATION. WE CHANGED THE EXPIRATION OF MOST OF THE SOUTHERN HALF
TO 6 AM MONDAY MORNING...HAVE THE NORTH HALF AT 18Z. THE SOUTH
SHORE IS A BIT MORE OF A CHALLENGE. THE SETUP FOR LAKE EFFECT SNOW
IS NOT IDEAL...AS STABILITY ISN`T AS LOW AS WE`D LIKE TO SEE.
BASED ON THE POSSIBILITY OF LAKE ENHANCED SNOWFALL AS 850MB
TEMPERATURES DROP IN THE AFTERNOON...WE KEPT THE EXPIRATION OF THE
WARNING FOR BAYFIELD...ASHLAND AND IRON COUNTIES AT 6 PM MONDAY.
THE DOUGLAS COUNTY WARNING WE CHANGED TO NOON MONDAY. LAKE
ENHANCED SNOWFALL WILL NOT OCCUR THERE...BUT THERE IS A CHANCE FOR
A GRAVITY WAVE INDUCED BAND OF SNOWFALL TO DEVELOP LATE TONIGHT
INTO MONDAY MORNING AS WINDS TURN NORTH TO NORTHWEST. THE RAP IS
SHOWING A FAIRLY STRONG GRAVITY WAVE SIGNAL...AND THE NAM BUFR
SOUNDINGS SHOW A PRETTY GOOD INVERSION DEVELOPING AROUND 2300FT
AGL BY 15Z. WE INCREASED SNOWFALL IN A BAND FROM NORTH
CENTRAL/NORTHWEST DOUGLAS COUNTY INTO SOUTHWEST DOUGLAS/EASTERN
CARLTON COUNTIES. LATER SHIFTS WILL HAVE TO MONITOR THIS CLOSELY
AS WE MAY NEED TO INCREASE SNOWFALL THERE FURTHER.
PREV DISCUSSION... /ISSUED 721 PM CST SUN FEB 10 2013/
UPDATE...
THE AREA OF VERY HEAVY SNOW...WITH RATES IN EXCESS OF OF AN INCH
PER HOUR HAS MOVED INTO FAR NORTHERN MINNESOTA. RADAR WAS SHOWING
OTHER AREAS OF SNOW...MOST MUCH LIGHTER...FURTHER SOUTH. A FEW
SPOTTERS HAVE REPORTED THE SNOW HAD ENDED FOR NOW...LIKE AT GURNEY.
WE EXPECT SNOW TO CONTINUE TONIGHT WITH AMOUNTS RANGING FROM 3 TO
6 INCHES ACROSS THE FAR NORTH WHERE FORCING WILL LAST LONGER. AREAS
FURTHER SOUTH WILL RANGE FROM 1 TO 4 INCHES TONIGHT...WITH
FREEZING DRIZZLE OR FREEZING RAIN POSSIBLE OVER ABOUT THE SOUTHERN
HALF OF THE NORTHLAND. IT WILL BE MOST LIKELY IN NORTHWEST
WISCONSIN WHERE SOUNDINGS SHOW THE BEST FREEZING DRIZZLE
SOUNDINGS. AN AREA OF HEAVIER PRECIPITATION WAS MOVING NORTH TOWARD
NORTHERN WISCONSIN...AND OBSERVATIONS UNDER THIS AREA OF
PRECIPITATION INDICATE MOSTLY RAIN...SO WE`LL HAVE TO WATCH CLOSELY
AS IT MOVES FURTHER NORTH.
AT THIS TIME...WE DID LEAVE ALL THE HEADLINES ALONE...WHICH EXPIRE
AT 00Z TUE. WE WILL LIKELY BE ABLE TO CANCEL SOME OF THESE
EARLIER...BUT WILL WAIT A BIT LONGER TO DO SO. ADDITIONAL SNOWFALL
ON MONDAY LOOKS TO BE LIMITED...BUT WOULD LIKE TO SEE SOME NEW
GUIDANCE BEFORE MAKING TO MANY DRASTIC CHANGES. THE EASTERN CWA
COULD SEE THE SNOW LINGER LONGEST...AND ACCUMULATIONS COULD BE AN
INCH OR TWO IN THE EAST.
PREV DISCUSSION... /ISSUED 539 PM CST SUN FEB 10 2013/
AVIATION...00Z TAFS
WIDESPREAD VLIFR/IFR CONDITIONS WILL OCCUR ACROSS MOST AREAS
TONIGHT...WITH THE VLIFR CONDITIONS MOST WIDESPREAD ACROSS FAR
NORTHERN MINNESOTA WHERE MANY OBSERVATIONS HAD 0.5SM OR LESS IN
SNOW. THE SNOW INTENSITY WILL DIMINISH AS THE EVENING PROGRESSES
FOR MOST AREAS OVERNIGHT...BUT THERE WILL STILL BE POCKETS OF
HEAVIER SNOW. CONDITIONS WILL IMPROVE FURTHER ON MONDAY. EAST/NORTHEAST
WILL VEER TO NORTH TO NORTHWEST BY 12Z.
PREV DISCUSSION... /ISSUED 300 PM CST SUN FEB 10 2013/
SHORT TERM...TONIGHT THROUGH MONDAY NIGHT.
LOW PRESSURE OVER NORTHERN IOWA WILL CONTINUE TO BRING SNOW TO MOST
OF THE NORTHLAND THIS EVENING. SOME LIGHT FREEZING RAIN AND SLEET
WILL STILL MIX IN WITH THE SNOW LATE THIS AFTERNOON OVER
NORTHWESTERN WISCONSIN. NORTHERLY WINDS AT 15 TO 20 MPH...WITH A FEW
GUSTS TO 25 MPH...ACROSS NORTHEASTERN MINNESOTA MAY LEAD TO SOME
BLOWING AND DRIFTING OF THE SNOW. WINDS WILL BE STRONGER NEAR LAKE
SUPERIOR. SNOW INTENSITY WILL COME DOWN A BIT AS THE LOW MOVES
NORTHEASTWARD INTO WISCONSIN LATE TONIGHT. THE CENTER OF THE LOW
WILL BE OVER THE UPPER PENINSULA OF MICHIGAN ON MONDAY MORNING AND
LIGHT SNOW WILL PERSIST OVER THE AREA. ADDITIONAL ACCUMULATIONS
DURING THE DAY ON MONDAY WILL GENERALLY BE UNDER AN INCH. WINDS WILL
BECOME MORE NORTHWESTERLY ON MONDAY AND THERE WILL BE SOME LAKE
ENHANCEMENT OF THE SNOW FOR THE GOGEBIC RANGE WHERE THERE COULD BE
UP TO TWO ADDITIONAL INCHES OF SNOW DURING THE DAY. THE LOW PUSHES
INTO EASTERN ONTARIO MONDAY NIGHT AND THE SNOW WILL END OVER MOST OF
THE NORTHLAND EXCEPT FOR AREAS OF THE SOUTH SHORE OF LAKE SUPERIOR
WHERE A FEW SNOW SHOWERS WILL LINGER DURING THE EVENING HOURS. HIGH
PRESSURE WILL BEGIN TO BUILD IN FROM THE CENTRAL PLAINS LATE MONDAY
NIGHT.
LONG TERM...TUESDAY THROUGH SUNDAY.
SOME LIGHT SNOW WILL BE POSSIBLE ACROSS THE AREA ON WEDNESDAY
AFTERNOON...AS A LOW PRESSURE SYSTEM MOVES TO THE FARGO AREA BY
00Z THURSDAY. THE LOW WILL THEN MOVE ACROSS CENTRAL MN AND INTO
NORTHERN TO CENTRAL WISCONSIN BY 12Z THURSDAY. HAVE INCREASED POPS
ACROSS THE AREA FOR WEDNESDAY NIGHT AND THURSDAY AS THE MODELS ARE
COMING INTO BETTER AGREEMENT CONCERNING THIS SYSTEM. THE GFS
CONTINUES TO BE STRONGER THAN THE ECMWF...BUT YESTERDAY THE ECMWF
DID NOT EVEN INDICATE THIS SYSTEM SO IT IS LIKELY LATCHING ONTO IT
BETTER. COLDER AIR WILL DRAG SOUTHWARD BEHIND THE DEPARTING SYSTEM
ON THURSDAY AND FRIDAY. GENERALLY DRY AND COOLER WEATHER IS THEN
IN STORE FOR SATURDAY AND SUNDAY. OVERALL NOT TOO MUCH IN THE WAY
OF PRECIPITATION THIS PERIOD WITH THE EXCEPTION OF A FEW INCHES OF
SNOW BEING POSSIBLE MID WEEK. TEMPS WILL BE ABOVE NORMAL FOR MUCH
OF THE EXTENDED...BUT IT WILL BE A BIT COOLER FOR THE WEEKEND.
AVIATION.../18Z TAF ISSUANCE/
A WINTER STORM WILL AFFECT THE NORTHLAND DURING THE TAF PERIOD.
THE STORM WILL BRING AN INCREASE IN SNOW AND POSSIBLY SOME
SNOW/ICE MIX IN EASTERN AREAS. CIGS AND VSBYS WILL GENERALLY BE IN
THE IFR/LIFR/VLIFR RANGE THROUGHOUT THE PERIOD...BUT TRANSITIONING
TO MORE OF AN MVFR SITUATION ON MONDAY MORNING. SNOW WILL COME
DOWN VERY HARD AT TIMES...WITH VSBYS LESS THAN A QUARTER MILE.
&&
.POINT TEMPS/POPS...
DLH 23 25 9 26 / 100 80 10 0
INL 18 22 7 26 / 100 90 10 0
BRD 24 26 9 27 / 100 80 10 0
HYR 26 29 10 27 / 100 90 10 0
ASX 27 29 11 27 / 100 90 20 0
&&
.DLH WATCHES/WARNINGS/ADVISORIES...
MN...WINTER STORM WARNING UNTIL NOON CST MONDAY FOR MNZ010>012-
018>021.
WINTER STORM WARNING UNTIL 6 AM CST MONDAY FOR MNZ025-026-
033>038.
WI...WINTER STORM WARNING UNTIL NOON CST MONDAY FOR WIZ001.
WINTER STORM WARNING UNTIL 6 AM CST MONDAY FOR WIZ006>009.
WINTER STORM WARNING UNTIL 6 PM CST MONDAY FOR WIZ002>004.
&&
$$
SHORT TERM...MELDE
AVIATION...MELDE
AREA FORECAST DISCUSSION
NWS HASTINGS NE
1121 AM CST MON FEB 11 2013
.AVIATION...18Z KGRI TAF. VFR CONDITIONS TO CONTINUE THROUGH THE
NEXT 24 HOURS. MID TO HIGH LEVEL CLOUDS WILL BE POSSIBLE AT THE
TERMINAL DURING THE TAF PERIOD...BUT NOTHING BELOW 7000FT AGL
CURRENTLY FORECAST. THE SURFACE WIND WILL REMAIN FROM THE
NORTHWEST TODAY...SUSTAINED AT AROUND 17KTS AND GUSTING AROUND
23KTS. THIS WIND WILL DIMINISH THROUGH THE AFTERNOON HOURS AND
EVENTUALLY BECOME LIGHT AND VARIABLE OVERNIGHT BEFORE BECOMING
MORE ESTABLISHED FROM THE SOUTHWEST DURING THE DAY TUESDAY.
VISIBILITY RESTRICTION IS NOT EXPECTED AT KGRI THROUGH THE NEXT 24
HOURS.
&&
.PREV DISCUSSION... /ISSUED 433 AM CST MON FEB 11 2013/
SHORT TERM...THROUGH WEDNESDAY NIGHT. COMPARED TO THE PAST FEW
DAYS...THESE NEXT 72 HOURS ARE LOOKING FAIRLY BENIGN WITH
ESSENTIALLY ZERO RISK OF PRECIPITATION. HOWEVER...BOTH TUESDAY AND
ESPECIALLY WEDNESDAY ARE TRENDING A BIT BREEZIER THAN PREVIOUSLY
ADVERTISED...BUT ALSO A BIT WARMER AS WELL.
09Z OBJECTIVE SURFACE ANALYSIS PLACED THE CENTER OF THE
DEPARTING...STRONG 991MB LOW OVER CENTRAL WI...WITH THE CENTRAL
PLAINS CAUGHT WITHIN THE BACKSIDE OF THE TIGHT PRESSURE GRADIENT
BETWEEN THIS LOW AND A ROUGHLY 1024MB HIGH OVER WY. A FAIRLY
PRONOUNCED GRADIENT IN WIND SPEEDS IS EVIDENT ACROSS THE CWA AT
THIS TIME...WITH NORTHWESTERLY SPEEDS AVERAGING NO MORE THAN 10-15
MPH IN SOUTHWEST AREAS...WHILE MOST CENTRAL/NORTHEAST AREAS
CONTINUE TO REPORT SUSTAINED SPEEDS AT LEAST 15-20 MPH WITH GUSTS
UP TO NEAR 30 MPH. FORTUNATELY THOUGH...SPEEDS HAVE FINALLY EASED
WELL BELOW ADVISORY CRITERIA...WHICH TOOK A FEW HOURS LONGER
EARLIER TONIGHT THAN ORIGINALLY THOUGHT. ANY LINGERING FLURRIES
FROM EARLIER TONIGHT HAVE ALSO DEPARTED TO THE NORTHEAST...WITH IN
FACT NEARLY FULLY CLEAR SKIES NOW OVER ALL BUT THE FAR EASTERN EDGES
OF THE CWA WHERE SOME LOW STRATUS LINGERS. PRE-DAWN TEMPERATURES ARE
FAIRLY UNIFORM ACROSS THE CWA...WITH MOST AREAS LIKELY HEADING FOR
LOWS SOMEWHERE BETWEEN 21-27. ALOFT...WATER VAPOR IMAGERY AND
SHORT TERM MODEL DATA CONFIRMED AN ACTIVE PATTERN ACROSS THE
CONUS...WITH THE NEARLY VERTICALLY STACKED CLOSED LOW DEPARTING
OVER THE WI AREA...WHILE OFF TO OUR SOUTHWEST...A CURRENTLY OPEN
500MB SHORTWAVE TROUGH WAS CENTERED NEAR THE CA/NV/UT/AZ
BORDERS...WITH ONLY THE SLIGHTEST HINT OF SHORTWAVE RIDGING OVER
THE CENTRAL HIGH PLAINS IN BETWEEN THESE TWO PRIMARY LOWS.
FORECAST-WISE TODAY...WHILE BY NO MEANS AS WINDY AS YESTERDAY...A
HEALTHY NORTHWEST BREEZE OF 15-20 MPH WITH GUSTS 25+ MPH WILL
PERSIST WELL INTO THE EARLY-MID AFTERNOON HOURS ACROSS ROUGHLY THE
NORTHEAST 1/2 OF THE CWA THANKS TO EFFICIENT MIXING TO AROUND
850MB...BEFORE EASING MORE NOTICEABLY BETWEEN 3 PM AND SUNSET. ANY
LINGERING/PRESUMABLY MINOR BLOWING SNOW ISSUES IN THE ORD AREA
SHOULD CONTINUE TO ABATE WITH TIME. WIND SPEEDS ACROSS ROUGHLY THE
SOUTHWEST 1/2 OF THE AREA WILL AVERAGE AT LEAST 5 MPH
LIGHTER...AND ALSO START TO EASE UP SOONER ESPECIALLY THIS
AFTERNOON AS A BROAD 1025MB RIDGE AXIS SETTLES INTO THE AREA.
CLOUD-WISE...WHILE NEARLY THE ENTIRE AREA WILL START OUT WITH
PLENTY OF SUNSHINE...THE AFTERNOON HOURS WILL BRING AT LEAST
PARTLY CLOUDY SKIES TO MAINLY THE SOUTHWEST 1/2 OF THE CWA AS MID-
HIGH CLOUDS SPREAD OVERHEAD DOWNSTREAM FROM THE SOUTHWEST CONUS
LOW. THERE ARE SUGGESTIONS FROM THE LATEST HRRR RUNS THAT SOME
SCATTERED LOW CLOUDS COULD ALSO INCREASE MAINLY THIS AFTERNOON IN
SOME AREAS NORTH OF I-80...BUT WILL KEEP IT A MOSTLY SUNNY THEME
HERE AT LEAST FOR NOW. AS FOR TEMPS...FOLLOWED THE 00Z NAM/05Z RAP
SOLUTION RATHER CLOSELY...WHICH RESULTED IN A 1-3 DEGREE UPWARD
NUDGE FROM PREVIOUS FORECAST...NOW RANGING FROM LOW 30S FAR
NORTH...MID 30S CENTRAL...LOW 40S SOUTH MAINLY KS ZONES. ITS WORTH
NOTING THAT THE 06Z NAM CAME IN COLDER FOR NORTHWEST
COUNTIES...BUT THIS APPEARS TO BE A RESULT OF AN OVERDONE MODEL-
INITIALIZED SNOW FIELD. THAT BEING SAID...CONFIDENCE IN TEMPS
ISN/T QUITE AS HIGH ESPECIALLY FOR THE ORD AREA...WHERE A LIGHT
COATING OF SNOW FROM YESTERDAY ALONG WITH A WIND DIRECTION BLOWING
OFF OF THE DEEPER SNOW COVER OVER THE SANDHILLS COULD WORK TO HOLD
THINGS DOWN A BIT.
THIS EVENING/TONIGHT...CONFIDENCE REMAINS HIGH THAT THE ENTIRE CWA
REMAINS PRECIPITATION-FREE...BUT THINGS DEFINITELY START TO TURN
MORE INTERESTING A FEW COUNTIES TO OUR SOUTH...AS THE
AFOREMENTIONED SOUTHWESTERN CONUS MID LEVEL SHORTWAVE TROUGH
STARTS CLOSING OFF A BIT AS IT HEADS EAST INTO NM. FORCING
DOWNSTREAM FROM THIS WAVE WILL SPREAD DECENT CHANCES FOR AT LEAST
LIGHT ACCUMULATING SNOW INTO MAINLY THE SOUTHWEST 1/4 OF
KS ESPECIALLY AFTER MIDNIGHT. WHILE A CONSENSUS OF VARIOUS MODELS
SUCH AS THE NAM/ECMWF/4KM WRF-NMM KEEPS ANY OF THIS SNOW AT LEAST
80 MILES SOUTH OF THE FAR SOUTHERN CWA...THE NEW 06Z GFS HAS
SUDDENLY TRENDED SLIGHTLY FARTHER NORTH...BRINGING AT LEAST A
DUSTING OF SNOW WITHIN ROUGHLY 20 MILES OF FAR SOUTHERN
ROOKS/OSBORNE COUNTIES. FOR NOW WILL DISCOUNT THIS RUN AS A
NORTHERN OUTLIER AND STAND FIRM THAT THIS SYSTEM WILL NOT BE AN
ISSUE FOR OUR CWA...AND BRING ONLY A PERIOD OF PARTLY/MOSTLY
CLOUDY SKIES TO MAINLY OUR SOUTHERN COUNTIES. AT THE SURFACE
TONIGHT...INITIALLY FAIRLY LIGHT/VARIABLE WINDS NEAR THE RIDGE
AXIS WILL TAKE ON A SLIGHTLY STEADIER SOUTHWESTERLY COMPONENT LATE
IN THE NIGHT IN RESPONSE TO A SUBTLE PASSING TROUGH AXIS. GIVEN
THESE LIGHT WESTERLY BREEZES AND ALSO A FAIR AMOUNT OF PASSING
CLOUD ESPECIALLY SOUTH...GENERALLY RAISED LOW TEMPS 2-4 DEGREES
FROM PREVIOUS GRIDS...WITH ALL BUT FAR NORTHWESTERN AREAS HOLDING
UP GENERALLY 17-22.
TUESDAY DAYTIME...IN A CONTINUATION FROM LATE WED NIGHT
ACCUMULATING SNOW WILL CONTINUE TO OUR SOUTH...TRACKING EASTWARD
MAINLY ALONG/SOUTH OF THE KS/OK BORDER...AS THE PRIMARY 500MB
SHORTWAVE ENDS UP OVER SOUTHERN/WESTERN OK BY DAYS END. AGAIN
THOUGH...NO LOCAL IMPACT ANTICIPATED OTHER THAN MORE MID-HIGH
CLOUD OVER KS ZONES VERSUS NEB ZONES. AT THE SURFACE...HIGH
PRESSURE CENTERED TO THE WEST WILL DRIVE A WESTERLY DOWNSLOPE WIND
COMPONENT ACROSS THE ENTIRE CWA...AND HAVE INCREASED SUSTAINED
SPEEDS CLOSER TO 15 MPH WITH HIGHER GUSTS MAINLY FOR THE NORTHERN
1/2 OF THE CWA. ASSUMING THAT SUNSHINE IS FAIRLY PLENTIFUL IN MOST
AREAS...AND GIVEN SLIGHT LOW LEVEL WARMING VERSUS MONDAY...SEE
LITTLE REASON WHY THIS DOWNSLOPE WIND WON/T BRING A DECENT BOOST
IN HIGH TEMPS...AND HAVE RAISED HIGHS GENERALLY 2-4 DEGREES FROM
PREVIOUS FORECAST...ESPECIALLY IN EASTERN AREAS FARTHEST REMOVED
FROM THE WESTERN/NORTH CENTRAL NEB SNOW FIELD. THIS NOW YIELDS
HIGHS IN THE MID-UPPER 40S MOST AREAS...EXCEPT LOW 40S FAR
NORTHWEST.
TUESDAY NIGHT...THE SOUTHERN CONUS SHORTWAVE TROUGH TREKS EAST
INTO THE AR/TN AREA...HELPING TRANSITION THE FLOW OVER THE CENTRAL
PLAINS TO MORE PRONOUNCED NORTHWESTERLY...BUT WITH NO IMPACTFUL
DISTURBANCES. ALTHOUGH A DECENT BATCH OF MID LEVEL CLOUDS COULD
SAG SOUTHWARD ACROSS THE CWA...NOT EVEN EXPECTING FLURRIES AT THIS
TIME. AT THE SURFACE...A LIGHT BUT STEADY 5-10 MPH WESTERN
COMPONENT SHOULD AGAIN HELP KEEP TEMPS FROM FALLING TOO FAR...AND
NUDGED UP PREVIOUS LOWS VERY SLIGHTLY...KEEPING MOST PLACES UP
BETWEEN 21-24 DEGREES.
WEDNESDAY...DRY NORTHWESTERLY FLOW ALOFT PERSISTS...AS THE LOCAL
AREA REMAINS DOWNSTREAM FROM A LOW AMPLITUDE/CLIPPER-TYPE
SHORTWAVE TROUGH SLIPPING OUT OF CANADA TO THE DAKOTAS/MN BORDER
AREA BY DAYS END. UNDER GENERALLY PARTLY CLOUDY SKIES...A
CONTINUED DOWNSLOPE WESTERLY WIND AND WARMER AIR EVIDENT ABOVE THE
SURFACE AT 850MB SHOULD CONTINUE THE WARMING TREND FROM
TUESDAY...AND HAVE MADE A VERY SLIGHT UPWARD NUDGE TO PREVIOUS
HIGHS WITH MOST OF THE CWA INTO THE 50-53 RANGE...EXCEPT COOLER
MID-UPPER 40S MAINLY IN OUR FAR NORTH/NORTHWEST FRINGES WHERE THE
SNOW FIELD COULD STILL POSSIBLY EXERT SOME INFLUENCE. THE OVERALL
BIGGEST CHANCE TO WEDNESDAY INVOLVED WIND SPEEDS...WHICH WERE UPPED AT
LEAST 6-8 MPH FROM PREVIOUS GRIDS INTO BREEZY TERRITORY...AND NOW
EXPECT SEVERAL HOURS OF SUSTAINED WEST-NORTHWEST SPEEDS 15-20 MPH
WITH SOME HIGHER GUSTS. FORTUNATELY FOR POSSIBLE FIRE WEATHER
CONCERNS...RELATIVE HUMIDITY VALUES ARE FORECAST TO FALL NO LOWER
THAN THE UPPER-20S PERCENT...AND THIS IS ONLY IN A SMALL PART OF
KS ZONES.
WEDNESDAY NIGHT...THE AFOREMENTIONED NORTHERN PLAINS CLIPPER-SYSTEM
DIVES DOWN MAINLY INTO IA/WI...WHILE AT THE SURFACE THE LEADING
EDGES OF A MODEST COLD FRONT WILL ENTER THE LOCAL AREA. ALTHOUGH THE
ORIENTATION OF THE UPPER JET ON THE WESTERN SIDE OF THIS
DISTURBANCE ALONG WITH SOME MID LEVEL RH PROGS FROM MODELS SUCH AS
THE 06Z NAM SUGGEST THAT A FEW FLURRIES MIGHT NOT BE OUT OF THE
QUESTION FOR PARTS OF THE CWA...WILL KEEP ALL PRECIP MENTION OUT
FOR NOW WITH POSSIBLY SLIGHTLY BETTER FLURRY CHANCES HOLDING OFF
UNTIL THE THURS DAYTIME HOURS. MADE VERY LITTLE CHANGE TO LOW
TEMPS WITH MID-UPPER 20S ALL AREAS.
LONG TERM...THURSDAY THROUGH SUNDAY...AT THE ONSET OF THE EXTENDED
PERIODS...100KT TO 120KT JET H3 JET STREAKS WILL NOSE SOUTH FM
ALBERTA ACROSS THE EASTERN SLOPES OF THE NORTHERN ROCKIES CARVING A
TROUGH ACROSS THE EASTERN TWO THIRDS OF THE CONUS. IN A NORTHWEST
FLOW REGIME ACROSS THE CENTRAL PLAINS...COLD AIR WILL BACK IN FM THE
NORTHEAST WITH THE MAIN THERMAL TROUGH ORIENTED FM ONTARIO THRU THE
GREAT LAKES REGION. ENERGY TRANSLATING SOUTHEAST THRU FLOW AND A
PUSH OF COLD AIR SOUTH THURSDAY COULD GENERATE SNOW FLURRIES IN OUR
NORTHERN ZONES. FRIDAY WILL SEE A REINFORCING SHOT OF COLD AIR AS A
STRONGER JET STREAK DIVES SOUTH ALONG THE FRONT RANGE OF THE ROCKIES
AND ADDITIONAL SHORTWAVE ENERGY TRANSLATES ON THE WESTERN EDGE OF
THE TROUGH WHICH ULTIMATELY FURTHER DEEPENS TO THE TROUGH ACROSS
CENTRAL AND EASTERN CONUS. CURRENTLY HAVE FLURRIES IN THE FORECAST
ON FRIDAY AND THIS IS STILL WARRANTED WITH FROPA/UPPER DYNAMICS.
TEMPS WILL TREND COLDER THURSDAY...CLOSER TO SEASONAL NORMALS...AND
WILL DROP FURTHER FRIDAY WITH STRONGER COLD FRONT.
A COLD SURFACE HIGH PRESSURE SYSTEM WILL SETTLE ACROSS THE CENTRAL
PLAINS BEHIND THE FRONT FRIDAY NIGHT...WHICH WILL RESULT IN TEMPS IN
THE TEENS FOR LOWS. AFTER A COLD COUPLE OF DAYS FOR THE END OF THE
WORKWEEK...THE WEATHER OVER THE WEEKEND TRENDS WARMER. THE SFC RIDGE
AXIS SLIDES SOUTHEAST ON SATURDAY...ALLOWING FOR RETURN FLOW...AND
ALOFT...THE UPPER TROUGH DEPARTS EASTWARD AND HEIGHTS BEGIN TO RISE
ACROSS THE CENTRAL PLAINS. BY SUNDAY THE RIDGE WHICH WAS OVER THE
ROCKIES SATURDAY REACHES THE INTERIOR CONUS..AND WARMER AIR SPREADS
EASTWARD. SUNDAY IS LOOKING LIKE THE WARMEST OF THE EXTENDED PERIODS
WITH HIGHS IN THE 40S FOR THE MOST PART AND 50S MAY NOT BE OUT OF
THE QUESTION.
&&
.GID WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
KS...NONE.
&&
$$
AVIATION...BRYANT
SHORT TERM...PFANNKUCH
LONG TERM...FAY
AREA FORECAST DISCUSSION
NWS HASTINGS NE
524 AM CST MON FEB 11 2013
.AVIATION...12Z TAF. MAIN CONCERN FOR THE FIRST PART OF THE TAF
PERIOD IS GUSTY NORTHWEST WINDS AS SFC PRESSURE GRADIENT WILL
REMAIN TIGHT THRU THE MORNING. WIND GUSTS NEAR 25KTS ARE POSSIBLE
UNTIL GRADIENT RELAXES THIS AFTN/EVENING AS SFC HIGH PRESSURE SETTLES
ONTO THE CENTRAL PLAINS. KGRI WILL BE ON THE SOUTHWEST EDGE OF
MVFR CLOUDS THIS MORNING...BUT BRUNT OF LOW CLOUDS ARE EXPECTED TO
REMAIN EAST AS THE UPPER LOW PRESSURE SYSTEM CONTINUES TO LIFT OUT
AND DID NOT BRING ANY CIGS INTO THE TERMINAL...THEN SCATTERED MID/HIGH
CLOUDS ARE EXPECTED TONIGHT.
&&
.PREV DISCUSSION... /ISSUED 433 AM CST MON FEB 11 2013/
SHORT TERM...THROUGH WEDNESDAY NIGHT. COMPARED TO THE PAST FEW
DAYS...THESE NEXT 72 HOURS ARE LOOKING FAIRLY BENIGN WITH
ESSENTIALLY ZERO RISK OF PRECIPITATION. HOWEVER...BOTH TUESDAY AND
ESPECIALLY WEDNESDAY ARE TRENDING A BIT BREEZIER THAN PREVIOUSLY
ADVERTISED...BUT ALSO A BIT WARMER AS WELL.
09Z OBJECTIVE SURFACE ANALYSIS PLACED THE CENTER OF THE
DEPARTING...STRONG 991MB LOW OVER CENTRAL WI...WITH THE CENTRAL
PLAINS CAUGHT WITHIN THE BACKSIDE OF THE TIGHT PRESSURE GRADIENT
BETWEEN THIS LOW AND A ROUGHLY 1024MB HIGH OVER WY. A FAIRLY
PRONOUNCED GRADIENT IN WIND SPEEDS IS EVIDENT ACROSS THE CWA AT
THIS TIME...WITH NORTHWESTERLY SPEEDS AVERAGING NO MORE THAN 10-15
MPH IN SOUTHWEST AREAS...WHILE MOST CENTRAL/NORTHEAST AREAS
CONTINUE TO REPORT SUSTAINED SPEEDS AT LEAST 15-20 MPH WITH GUSTS
UP TO NEAR 30 MPH. FORTUNATELY THOUGH...SPEEDS HAVE FINALLY EASED
WELL BELOW ADVISORY CRITERIA...WHICH TOOK A FEW HOURS LONGER
EARLIER TONIGHT THAN ORIGINALLY THOUGHT. ANY LINGERING FLURRIES
FROM EARLIER TONIGHT HAVE ALSO DEPARTED TO THE NORTHEAST...WITH IN
FACT NEARLY FULLY CLEAR SKIES NOW OVER ALL BUT THE FAR EASTERN EDGES
OF THE CWA WHERE SOME LOW STRATUS LINGERS. PRE-DAWN TEMPERATURES ARE
FAIRLY UNIFORM ACROSS THE CWA...WITH MOST AREAS LIKELY HEADING FOR
LOWS SOMEWHERE BETWEEN 21-27. ALOFT...WATER VAPOR IMAGERY AND
SHORT TERM MODEL DATA CONFIRMED AN ACTIVE PATTERN ACROSS THE
CONUS...WITH THE NEARLY VERTICALLY STACKED CLOSED LOW DEPARTING
OVER THE WI AREA...WHILE OFF TO OUR SOUTHWEST...A CURRENTLY OPEN
500MB SHORTWAVE TROUGH WAS CENTERED NEAR THE CA/NV/UT/AZ
BORDERS...WITH ONLY THE SLIGHTEST HINT OF SHORTWAVE RIDGING OVER
THE CENTRAL HIGH PLAINS IN BETWEEN THESE TWO PRIMARY LOWS.
FORECAST-WISE TODAY...WHILE BY NO MEANS AS WINDY AS YESTERDAY...A
HEALTHY NORTHWEST BREEZE OF 15-20 MPH WITH GUSTS 25+ MPH WILL
PERSIST WELL INTO THE EARLY-MID AFTERNOON HOURS ACROSS ROUGHLY THE
NORTHEAST 1/2 OF THE CWA THANKS TO EFFICIENT MIXING TO AROUND
850MB...BEFORE EASING MORE NOTICEABLY BETWEEN 3 PM AND SUNSET. ANY
LINGERING/PRESUMABLY MINOR BLOWING SNOW ISSUES IN THE ORD AREA
SHOULD CONTINUE TO ABATE WITH TIME. WIND SPEEDS ACROSS ROUGHLY THE
SOUTHWEST 1/2 OF THE AREA WILL AVERAGE AT LEAST 5 MPH
LIGHTER...AND ALSO START TO EASE UP SOONER ESPECIALLY THIS
AFTERNOON AS A BROAD 1025MB RIDGE AXIS SETTLES INTO THE AREA.
CLOUD-WISE...WHILE NEARLY THE ENTIRE AREA WILL START OUT WITH
PLENTY OF SUNSHINE...THE AFTERNOON HOURS WILL BRING AT LEAST
PARTLY CLOUDY SKIES TO MAINLY THE SOUTHWEST 1/2 OF THE CWA AS MID-
HIGH CLOUDS SPREAD OVERHEAD DOWNSTREAM FROM THE SOUTHWEST CONUS
LOW. THERE ARE SUGGESTIONS FROM THE LATEST HRRR RUNS THAT SOME
SCATTERED LOW CLOUDS COULD ALSO INCREASE MAINLY THIS AFTERNOON IN
SOME AREAS NORTH OF I-80...BUT WILL KEEP IT A MOSTLY SUNNY THEME
HERE AT LEAST FOR NOW. AS FOR TEMPS...FOLLOWED THE 00Z NAM/05Z RAP
SOLUTION RATHER CLOSELY...WHICH RESULTED IN A 1-3 DEGREE UPWARD
NUDGE FROM PREVIOUS FORECAST...NOW RANGING FROM LOW 30S FAR
NORTH...MID 30S CENTRAL...LOW 40S SOUTH MAINLY KS ZONES. ITS WORTH
NOTING THAT THE 06Z NAM CAME IN COLDER FOR NORTHWEST
COUNTIES...BUT THIS APPEARS TO BE A RESULT OF AN OVERDONE MODEL-
INITIALIZED SNOW FIELD. THAT BEING SAID...CONFIDENCE IN TEMPS
ISN/T QUITE AS HIGH ESPECIALLY FOR THE ORD AREA...WHERE A LIGHT
COATING OF SNOW FROM YESTERDAY ALONG WITH A WIND DIRECTION BLOWING
OFF OF THE DEEPER SNOW COVER OVER THE SANDHILLS COULD WORK TO HOLD
THINGS DOWN A BIT.
THIS EVENING/TONIGHT...CONFIDENCE REMAINS HIGH THAT THE ENTIRE CWA
REMAINS PRECIPITATION-FREE...BUT THINGS DEFINITELY START TO TURN
MORE INTERESTING A FEW COUNTIES TO OUR SOUTH...AS THE
AFOREMENTIONED SOUTHWESTERN CONUS MID LEVEL SHORTWAVE TROUGH
STARTS CLOSING OFF A BIT AS IT HEADS EAST INTO NM. FORCING
DOWNSTREAM FROM THIS WAVE WILL SPREAD DECENT CHANCES FOR AT LEAST
LIGHT ACCUMULATING SNOW INTO MAINLY THE SOUTHWEST 1/4 OF
KS ESPECIALLY AFTER MIDNIGHT. WHILE A CONSENSUS OF VARIOUS MODELS
SUCH AS THE NAM/ECMWF/4KM WRF-NMM KEEPS ANY OF THIS SNOW AT LEAST
80 MILES SOUTH OF THE FAR SOUTHERN CWA...THE NEW 06Z GFS HAS
SUDDENLY TRENDED SLIGHTLY FARTHER NORTH...BRINGING AT LEAST A
DUSTING OF SNOW WITHIN ROUGHLY 20 MILES OF FAR SOUTHERN
ROOKS/OSBORNE COUNTIES. FOR NOW WILL DISCOUNT THIS RUN AS A
NORTHERN OUTLIER AND STAND FIRM THAT THIS SYSTEM WILL NOT BE AN
ISSUE FOR OUR CWA...AND BRING ONLY A PERIOD OF PARTLY/MOSTLY
CLOUDY SKIES TO MAINLY OUR SOUTHERN COUNTIES. AT THE SURFACE
TONIGHT...INITIALLY FAIRLY LIGHT/VARIABLE WINDS NEAR THE RIDGE
AXIS WILL TAKE ON A SLIGHTLY STEADIER SOUTHWESTERLY COMPONENT LATE
IN THE NIGHT IN RESPONSE TO A SUBTLE PASSING TROUGH AXIS. GIVEN
THESE LIGHT WESTERLY BREEZES AND ALSO A FAIR AMOUNT OF PASSING
CLOUD ESPECIALLY SOUTH...GENERALLY RAISED LOW TEMPS 2-4 DEGREES
FROM PREVIOUS GRIDS...WITH ALL BUT FAR NORTHWESTERN AREAS HOLDING
UP GENERALLY 17-22.
TUESDAY DAYTIME...IN A CONTINUATION FROM LATE WED NIGHT
ACCUMULATING SNOW WILL CONTINUE TO OUR SOUTH...TRACKING EASTWARD
MAINLY ALONG/SOUTH OF THE KS/OK BORDER...AS THE PRIMARY 500MB
SHORTWAVE ENDS UP OVER SOUTHERN/WESTERN OK BY DAYS END. AGAIN
THOUGH...NO LOCAL IMPACT ANTICIPATED OTHER THAN MORE MID-HIGH
CLOUD OVER KS ZONES VERSUS NEB ZONES. AT THE SURFACE...HIGH
PRESSURE CENTERED TO THE WEST WILL DRIVE A WESTERLY DOWNSLOPE WIND
COMPONENT ACROSS THE ENTIRE CWA...AND HAVE INCREASED SUSTAINED
SPEEDS CLOSER TO 15 MPH WITH HIGHER GUSTS MAINLY FOR THE NORTHERN
1/2 OF THE CWA. ASSUMING THAT SUNSHINE IS FAIRLY PLENTIFUL IN MOST
AREAS...AND GIVEN SLIGHT LOW LEVEL WARMING VERSUS MONDAY...SEE
LITTLE REASON WHY THIS DOWNSLOPE WIND WON/T BRING A DECENT BOOST
IN HIGH TEMPS...AND HAVE RAISED HIGHS GENERALLY 2-4 DEGREES FROM
PREVIOUS FORECAST...ESPECIALLY IN EASTERN AREAS FARTHEST REMOVED
FROM THE WESTERN/NORTH CENTRAL NEB SNOW FIELD. THIS NOW YIELDS
HIGHS IN THE MID-UPPER 40S MOST AREAS...EXCEPT LOW 40S FAR
NORTHWEST.
TUESDAY NIGHT...THE SOUTHERN CONUS SHORTWAVE TROUGH TREKS EAST
INTO THE AR/TN AREA...HELPING TRANSITION THE FLOW OVER THE CENTRAL
PLAINS TO MORE PRONOUNCED NORTHWESTERLY...BUT WITH NO IMPACTFUL
DISTURBANCES. ALTHOUGH A DECENT BATCH OF MID LEVEL CLOUDS COULD
SAG SOUTHWARD ACROSS THE CWA...NOT EVEN EXPECTING FLURRIES AT THIS
TIME. AT THE SURFACE...A LIGHT BUT STEADY 5-10 MPH WESTERN
COMPONENT SHOULD AGAIN HELP KEEP TEMPS FROM FALLING TOO FAR...AND
NUDGED UP PREVIOUS LOWS VERY SLIGHTLY...KEEPING MOST PLACES UP
BETWEEN 21-24 DEGREES.
WEDNESDAY...DRY NORTHWESTERLY FLOW ALOFT PERSISTS...AS THE LOCAL
AREA REMAINS DOWNSTREAM FROM A LOW AMPLITUDE/CLIPPER-TYPE
SHORTWAVE TROUGH SLIPPING OUT OF CANADA TO THE DAKOTAS/MN BORDER
AREA BY DAYS END. UNDER GENERALLY PARTLY CLOUDY SKIES...A
CONTINUED DOWNSLOPE WESTERLY WIND AND WARMER AIR EVIDENT ABOVE THE
SURFACE AT 850MB SHOULD CONTINUE THE WARMING TREND FROM
TUESDAY...AND HAVE MADE A VERY SLIGHT UPWARD NUDGE TO PREVIOUS
HIGHS WITH MOST OF THE CWA INTO THE 50-53 RANGE...EXCEPT COOLER
MID-UPPER 40S MAINLY IN OUR FAR NORTH/NORTHWEST FRINGES WHERE THE
SNOW FIELD COULD STILL POSSIBLY EXERT SOME INFLUENCE. THE OVERALL
BIGGEST CHANCE TO WEDNESDAY INVOLVED WIND SPEEDS...WHICH WERE UPPED AT
LEAST 6-8 MPH FROM PREVIOUS GRIDS INTO BREEZY TERRITORY...AND NOW
EXPECT SEVERAL HOURS OF SUSTAINED WEST-NORTHWEST SPEEDS 15-20 MPH
WITH SOME HIGHER GUSTS. FORTUNATELY FOR POSSIBLE FIRE WEATHER
CONCERNS...RELATIVE HUMIDITY VALUES ARE FORECAST TO FALL NO LOWER
THAN THE UPPER-20S PERCENT...AND THIS IS ONLY IN A SMALL PART OF
KS ZONES.
WEDNESDAY NIGHT...THE AFOREMENTIONED NORTHERN PLAINS CLIPPER-SYSTEM
DIVES DOWN MAINLY INTO IA/WI...WHILE AT THE SURFACE THE LEADING
EDGES OF A MODEST COLD FRONT WILL ENTER THE LOCAL AREA. ALTHOUGH THE
ORIENTATION OF THE UPPER JET ON THE WESTERN SIDE OF THIS
DISTURBANCE ALONG WITH SOME MID LEVEL RH PROGS FROM MODELS SUCH AS
THE 06Z NAM SUGGEST THAT A FEW FLURRIES MIGHT NOT BE OUT OF THE
QUESTION FOR PARTS OF THE CWA...WILL KEEP ALL PRECIP MENTION OUT
FOR NOW WITH POSSIBLY SLIGHTLY BETTER FLURRY CHANCES HOLDING OFF
UNTIL THE THURS DAYTIME HOURS. MADE VERY LITTLE CHANGE TO LOW
TEMPS WITH MID-UPPER 20S ALL AREAS.
LONG TERM...THURSDAY THROUGH SUNDAY...AT THE ONSET OF THE EXTENDED
PERIODS...100KT TO 120KT JET H3 JET STREAKS WILL NOSE SOUTH FM
ALBERTA ACROSS THE EASTERN SLOPES OF THE NORTHERN ROCKIES CARVING A
TROUGH ACROSS THE EASTERN TWO THIRDS OF THE CONUS. IN A NORTHWEST
FLOW REGIME ACROSS THE CENTRAL PLAINS...COLD AIR WILL BACK IN FM THE
NORTHEAST WITH THE MAIN THERMAL TROUGH ORIENTED FM ONTARIO THRU THE
GREAT LAKES REGION. ENERGY TRANSLATING SOUTHEAST THRU FLOW AND A
PUSH OF COLD AIR SOUTH THURSDAY COULD GENERATE SNOW FLURRIES IN OUR
NORTHERN ZONES. FRIDAY WILL SEE A REINFORCING SHOT OF COLD AIR AS A
STRONGER JET STREAK DIVES SOUTH ALONG THE FRONT RANGE OF THE ROCKIES
AND ADDITIONAL SHORTWAVE ENERGY TRANSLATES ON THE WESTERN EDGE OF
THE TROUGH WHICH ULTIMATELY FURTHER DEEPENS TO THE TROUGH ACROSS
CENTRAL AND EASTERN CONUS. CURRENTLY HAVE FLURRIES IN THE FORECAST
ON FRIDAY AND THIS IS STILL WARRANTED WITH FROPA/UPPER DYNAMICS.
TEMPS WILL TREND COLDER THURSDAY...CLOSER TO SEASONAL NORMALS...AND
WILL DROP FURTHER FRIDAY WITH STRONGER COLD FRONT.
A COLD SURFACE HIGH PRESSURE SYSTEM WILL SETTLE ACROSS THE CENTRAL
PLAINS BEHIND THE FRONT FRIDAY NIGHT...WHICH WILL RESULT IN TEMPS IN
THE TEENS FOR LOWS. AFTER A COLD COUPLE OF DAYS FOR THE END OF THE
WORKWEEK...THE WEATHER OVER THE WEEKEND TRENDS WARMER. THE SFC RIDGE
AXIS SLIDES SOUTHEAST ON SATURDAY...ALLOWING FOR RETURN FLOW...AND
ALOFT...THE UPPER TROUGH DEPARTS EASTWARD AND HEIGHTS BEGIN TO RISE
ACROSS THE CENTRAL PLAINS. BY SUNDAY THE RIDGE WHICH WAS OVER THE
ROCKIES SATURDAY REACHES THE INTERIOR CONUS..AND WARMER AIR SPREADS
EASTWARD. SUNDAY IS LOOKING LIKE THE WARMEST OF THE EXTENDED PERIODS
WITH HIGHS IN THE 40S FOR THE MOST PART AND 50S MAY NOT BE OUT OF
THE QUESTION.
&&
.GID WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
KS...NONE.
&&
$$
SHORT TERM...PFANNKUCH
LONG TERM/AVIATION...FAY
AREA FORECAST DISCUSSION
NWS HASTINGS NE
433 AM CST MON FEB 11 2013
.SHORT TERM...THROUGH WEDNESDAY NIGHT. COMPARED TO THE PAST FEW
DAYS...THESE NEXT 72 HOURS ARE LOOKING FAIRLY BENIGN WITH
ESSENTIALLY ZERO RISK OF PRECIPITATION. HOWEVER...BOTH TUESDAY AND
ESPECIALLY WEDNESDAY ARE TRENDING A BIT BREEZIER THAN PREVIOUSLY
ADVERTISED...BUT ALSO A BIT WARMER AS WELL.
09Z OBJECTIVE SURFACE ANALYSIS PLACED THE CENTER OF THE
DEPARTING...STRONG 991MB LOW OVER CENTRAL WI...WITH THE CENTRAL
PLAINS CAUGHT WITHIN THE BACKSIDE OF THE TIGHT PRESSURE GRADIENT
BETWEEN THIS LOW AND A ROUGHLY 1024MB HIGH OVER WY. A FAIRLY
PRONOUNCED GRADIENT IN WIND SPEEDS IS EVIDENT ACROSS THE CWA AT
THIS TIME...WITH NORTHWESTERLY SPEEDS AVERAGING NO MORE THAN 10-15
MPH IN SOUTHWEST AREAS...WHILE MOST CENTRAL/NORTHEAST AREAS
CONTINUE TO REPORT SUSTAINED SPEEDS AT LEAST 15-20 MPH WITH GUSTS
UP TO NEAR 30 MPH. FORTUNATELY THOUGH...SPEEDS HAVE FINALLY EASED
WELL BELOW ADVISORY CRITERIA...WHICH TOOK A FEW HOURS LONGER
EARLIER TONIGHT THAN ORIGINALLY THOUGHT. ANY LINGERING FLURRIES
FROM EARLIER TONIGHT HAVE ALSO DEPARTED TO THE NORTHEAST...WITH IN
FACT NEARLY FULLY CLEAR SKIES NOW OVER ALL BUT THE FAR EASTERN EDGES
OF THE CWA WHERE SOME LOW STRATUS LINGERS. PRE-DAWN TEMPERATURES ARE
FAIRLY UNIFORM ACROSS THE CWA...WITH MOST AREAS LIKELY HEADING FOR
LOWS SOMEWHERE BETWEEN 21-27. ALOFT...WATER VAPOR IMAGERY AND
SHORT TERM MODEL DATA CONFIRMED AN ACTIVE PATTERN ACROSS THE
CONUS...WITH THE NEARLY VERTICALLY STACKED CLOSED LOW DEPARTING
OVER THE WI AREA...WHILE OFF TO OUR SOUTHWEST...A CURRENTLY OPEN
500MB SHORTWAVE TROUGH WAS CENTERED NEAR THE CA/NV/UT/AZ
BORDERS...WITH ONLY THE SLIGHTEST HINT OF SHORTWAVE RIDGING OVER
THE CENTRAL HIGH PLAINS IN BETWEEN THESE TWO PRIMARY LOWS.
FORECAST-WISE TODAY...WHILE BY NO MEANS AS WINDY AS YESTERDAY...A
HEALTHY NORTHWEST BREEZE OF 15-20 MPH WITH GUSTS 25+ MPH WILL
PERSIST WELL INTO THE EARLY-MID AFTERNOON HOURS ACROSS ROUGHLY THE
NORTHEAST 1/2 OF THE CWA THANKS TO EFFICIENT MIXING TO AROUND
850MB...BEFORE EASING MORE NOTICEABLY BETWEEN 3 PM AND SUNSET. ANY
LINGERING/PRESUMABLY MINOR BLOWING SNOW ISSUES IN THE ORD AREA
SHOULD CONTINUE TO ABATE WITH TIME. WIND SPEEDS ACROSS ROUGHLY THE
SOUTHWEST 1/2 OF THE AREA WILL AVERAGE AT LEAST 5 MPH
LIGHTER...AND ALSO START TO EASE UP SOONER ESPECIALLY THIS
AFTERNOON AS A BROAD 1025MB RIDGE AXIS SETTLES INTO THE AREA.
CLOUD-WISE...WHILE NEARLY THE ENTIRE AREA WILL START OUT WITH
PLENTY OF SUNSHINE...THE AFTERNOON HOURS WILL BRING AT LEAST
PARTLY CLOUDY SKIES TO MAINLY THE SOUTHWEST 1/2 OF THE CWA AS MID-
HIGH CLOUDS SPREAD OVERHEAD DOWNSTREAM FROM THE SOUTHWEST CONUS
LOW. THERE ARE SUGGESTIONS FROM THE LATEST HRRR RUNS THAT SOME
SCATTERED LOW CLOUDS COULD ALSO INCREASE MAINLY THIS AFTERNOON IN
SOME AREAS NORTH OF I-80...BUT WILL KEEP IT A MOSTLY SUNNY THEME
HERE AT LEAST FOR NOW. AS FOR TEMPS...FOLLOWED THE 00Z NAM/05Z RAP
SOLUTION RATHER CLOSELY...WHICH RESULTED IN A 1-3 DEGREE UPWARD
NUDGE FROM PREVIOUS FORECAST...NOW RANGING FROM LOW 30S FAR
NORTH...MID 30S CENTRAL...LOW 40S SOUTH MAINLY KS ZONES. ITS WORTH
NOTING THAT THE 06Z NAM CAME IN COLDER FOR NORTHWEST
COUNTIES...BUT THIS APPEARS TO BE A RESULT OF AN OVERDONE MODEL-
INITIALIZED SNOW FIELD. THAT BEING SAID...CONFIDENCE IN TEMPS
ISN/T QUITE AS HIGH ESPECIALLY FOR THE ORD AREA...WHERE A LIGHT
COATING OF SNOW FROM YESTERDAY ALONG WITH A WIND DIRECTION BLOWING
OFF OF THE DEEPER SNOW COVER OVER THE SANDHILLS COULD WORK TO HOLD
THINGS DOWN A BIT.
THIS EVENING/TONIGHT...CONFIDENCE REMAINS HIGH THAT THE ENTIRE CWA
REMAINS PRECIPITATION-FREE...BUT THINGS DEFINITELY START TO TURN
MORE INTERESTING A FEW COUNTIES TO OUR SOUTH...AS THE
AFOREMENTIONED SOUTHWESTERN CONUS MID LEVEL SHORTWAVE TROUGH
STARTS CLOSING OFF A BIT AS IT HEADS EAST INTO NM. FORCING
DOWNSTREAM FROM THIS WAVE WILL SPREAD DECENT CHANCES FOR AT LEAST
LIGHT ACCUMULATING SNOW INTO MAINLY THE SOUTHWEST 1/4 OF
KS ESPECIALLY AFTER MIDNIGHT. WHILE A CONSENSUS OF VARIOUS MODELS
SUCH AS THE NAM/ECMWF/4KM WRF-NMM KEEPS ANY OF THIS SNOW AT LEAST
80 MILES SOUTH OF THE FAR SOUTHERN CWA...THE NEW 06Z GFS HAS
SUDDENLY TRENDED SLIGHTLY FARTHER NORTH...BRINGING AT LEAST A
DUSTING OF SNOW WITHIN ROUGHLY 20 MILES OF FAR SOUTHERN
ROOKS/OSBORNE COUNTIES. FOR NOW WILL DISCOUNT THIS RUN AS A
NORTHERN OUTLIER AND STAND FIRM THAT THIS SYSTEM WILL NOT BE AN
ISSUE FOR OUR CWA...AND BRING ONLY A PERIOD OF PARTLY/MOSTLY
CLOUDY SKIES TO MAINLY OUR SOUTHERN COUNTIES. AT THE SURFACE
TONIGHT...INITIALLY FAIRLY LIGHT/VARIABLE WINDS NEAR THE RIDGE
AXIS WILL TAKE ON A SLIGHTLY STEADIER SOUTHWESTERLY COMPONENT LATE
IN THE NIGHT IN RESPONSE TO A SUBTLE PASSING TROUGH AXIS. GIVEN
THESE LIGHT WESTERLY BREEZES AND ALSO A FAIR AMOUNT OF PASSING
CLOUD ESPECIALLY SOUTH...GENERALLY RAISED LOW TEMPS 2-4 DEGREES
FROM PREVIOUS GRIDS...WITH ALL BUT FAR NORTHWESTERN AREAS HOLDING
UP GENERALLY 17-22.
TUESDAY DAYTIME...IN A CONTINUATION FROM LATE WED NIGHT
ACCUMULATING SNOW WILL CONTINUE TO OUR SOUTH...TRACKING EASTWARD
MAINLY ALONG/SOUTH OF THE KS/OK BORDER...AS THE PRIMARY 500MB
SHORTWAVE ENDS UP OVER SOUTHERN/WESTERN OK BY DAYS END. AGAIN
THOUGH...NO LOCAL IMPACT ANTICIPATED OTHER THAN MORE MID-HIGH
CLOUD OVER KS ZONES VERSUS NEB ZONES. AT THE SURFACE...HIGH
PRESSURE CENTERED TO THE WEST WILL DRIVE A WESTERLY DOWNSLOPE WIND
COMPONENT ACROSS THE ENTIRE CWA...AND HAVE INCREASED SUSTAINED
SPEEDS CLOSER TO 15 MPH WITH HIGHER GUSTS MAINLY FOR THE NORTHERN
1/2 OF THE CWA. ASSUMING THAT SUNSHINE IS FAIRLY PLENTIFUL IN MOST
AREAS...AND GIVEN SLIGHT LOW LEVEL WARMING VERSUS MONDAY...SEE
LITTLE REASON WHY THIS DOWNSLOPE WIND WON/T BRING A DECENT BOOST
IN HIGH TEMPS...AND HAVE RAISED HIGHS GENERALLY 2-4 DEGREES FROM
PREVIOUS FORECAST...ESPECIALLY IN EASTERN AREAS FARTHEST REMOVED
FROM THE WESTERN/NORTH CENTRAL NEB SNOW FIELD. THIS NOW YIELDS
HIGHS IN THE MID-UPPER 40S MOST AREAS...EXCEPT LOW 40S FAR
NORTHWEST.
TUESDAY NIGHT...THE SOUTHERN CONUS SHORTWAVE TROUGH TREKS EAST
INTO THE AR/TN AREA...HELPING TRANSITION THE FLOW OVER THE CENTRAL
PLAINS TO MORE PRONOUNCED NORTHWESTERLY...BUT WITH NO IMPACTFUL
DISTURBANCES. ALTHOUGH A DECENT BATCH OF MID LEVEL CLOUDS COULD
SAG SOUTHWARD ACROSS THE CWA...NOT EVEN EXPECTING FLURRIES AT THIS
TIME. AT THE SURFACE...A LIGHT BUT STEADY 5-10 MPH WESTERN
COMPONENT SHOULD AGAIN HELP KEEP TEMPS FROM FALLING TOO FAR...AND
NUDGED UP PREVIOUS LOWS VERY SLIGHTLY...KEEPING MOST PLACES UP
BETWEEN 21-24 DEGREES.
WEDNESDAY...DRY NORTHWESTERLY FLOW ALOFT PERSISTS...AS THE LOCAL
AREA REMAINS DOWNSTREAM FROM A LOW AMPLITUDE/CLIPPER-TYPE
SHORTWAVE TROUGH SLIPPING OUT OF CANADA TO THE DAKOTAS/MN BORDER
AREA BY DAYS END. UNDER GENERALLY PARTLY CLOUDY SKIES...A
CONTINUED DOWNSLOPE WESTERLY WIND AND WARMER AIR EVIDENT ABOVE THE
SURFACE AT 850MB SHOULD CONTINUE THE WARMING TREND FROM
TUESDAY...AND HAVE MADE A VERY SLIGHT UPWARD NUDGE TO PREVIOUS
HIGHS WITH MOST OF THE CWA INTO THE 50-53 RANGE...EXCEPT COOLER
MID-UPPER 40S MAINLY IN OUR FAR NORTH/NORTHWEST FRINGES WHERE THE
SNOW FIELD COULD STILL POSSIBLY EXERT SOME INFLUENCE. THE OVERALL
BIGGEST CHANCE TO WEDNESDAY INVOLVED WIND SPEEDS...WHICH WERE UPPED AT
LEAST 6-8 MPH FROM PREVIOUS GRIDS INTO BREEZY TERRITORY...AND NOW
EXPECT SEVERAL HOURS OF SUSTAINED WEST-NORTHWEST SPEEDS 15-20 MPH
WITH SOME HIGHER GUSTS. FORTUNATELY FOR POSSIBLE FIRE WEATHER
CONCERNS...RELATIVE HUMIDITY VALUES ARE FORECAST TO FALL NO LOWER
THAN THE UPPER-20S PERCENT...AND THIS IS ONLY IN A SMALL PART OF
KS ZONES.
WEDNESDAY NIGHT...THE AFOREMENTIONED NORTHERN PLAINS CLIPPER-SYSTEM
DIVES DOWN MAINLY INTO IA/WI...WHILE AT THE SURFACE THE LEADING
EDGES OF A MODEST COLD FRONT WILL ENTER THE LOCAL AREA. ALTHOUGH THE
ORIENTATION OF THE UPPER JET ON THE WESTERN SIDE OF THIS
DISTURBANCE ALONG WITH SOME MID LEVEL RH PROGS FROM MODELS SUCH AS
THE 06Z NAM SUGGEST THAT A FEW FLURRIES MIGHT NOT BE OUT OF THE
QUESTION FOR PARTS OF THE CWA...WILL KEEP ALL PRECIP MENTION OUT
FOR NOW WITH POSSIBLY SLIGHTLY BETTER FLURRY CHANCES HOLDING OFF
UNTIL THE THURS DAYTIME HOURS. MADE VERY LITTLE CHANGE TO LOW
TEMPS WITH MID-UPPER 20S ALL AREAS.
.LONG TERM...THURSDAY THROUGH SUNDAY...AT THE ONSET OF THE EXTENDED
PERIODS...100KT TO 120KT JET H3 JET STREAKS WILL NOSE SOUTH FM
ALBERTA ACROSS THE EASTERN SLOPES OF THE NORTHERN ROCKIES CARVING A
TROUGH ACROSS THE EASTERN TWO THIRDS OF THE CONUS. IN A NORTHWEST
FLOW REGIME ACROSS THE CENTRAL PLAINS...COLD AIR WILL BACK IN FM THE
NORTHEAST WITH THE MAIN THERMAL TROUGH ORIENTED FM ONTARIO THRU THE
GREAT LAKES REGION. ENERGY TRANSLATING SOUTHEAST THRU FLOW AND A
PUSH OF COLD AIR SOUTH THURSDAY COULD GENERATE SNOW FLURRIES IN OUR
NORTHERN ZONES. FRIDAY WILL SEE A REINFORCING SHOT OF COLD AIR AS A
STRONGER JET STREAK DIVES SOUTH ALONG THE FRONT RANGE OF THE ROCKIES
AND ADDITIONAL SHORTWAVE ENERGY TRANSLATES ON THE WESTERN EDGE OF
THE TROUGH WHICH ULTIMATELY FURTHER DEEPENS TO THE TROUGH ACROSS
CENTRAL AND EASTERN CONUS. CURRENTLY HAVE FLURRIES IN THE FORECAST
ON FRIDAY AND THIS IS STILL WARRANTED WITH FROPA/UPPER DYNAMICS.
TEMPS WILL TREND COLDER THURSDAY...CLOSER TO SEASONAL NORMALS...AND
WILL DROP FURTHER FRIDAY WITH STRONGER COLD FRONT.
A COLD SURFACE HIGH PRESSURE SYSTEM WILL SETTLE ACROSS THE CENTRAL
PLAINS BEHIND THE FRONT FRIDAY NIGHT...WHICH WILL RESULT IN TEMPS IN
THE TEENS FOR LOWS. AFTER A COLD COUPLE OF DAYS FOR THE END OF THE
WORKWEEK...THE WEATHER OVER THE WEEKEND TRENDS WARMER. THE SFC RIDGE
AXIS SLIDES SOUTHEAST ON SATURDAY...ALLOWING FOR RETURN FLOW...AND
ALOFT...THE UPPER TROUGH DEPARTS EASTWARD AND HEIGHTS BEGIN TO RISE
ACROSS THE CENTRAL PLAINS. BY SUNDAY THE RIDGE WHICH WAS OVER THE
ROCKIES SATURDAY REACHES THE INTERIOR CONUS..AND WARMER AIR SPREADS
EASTWARD. SUNDAY IS LOOKING LIKE THE WARMEST OF THE EXTENDED PERIODS
WITH HIGHS IN THE 40S FOR THE MOST PART AND 50S MAY NOT BE OUT OF
THE QUESTION.
&&
.PREV DISCUSSION... /ISSUED 1050 PM CST SUN FEB 10 2013/
AVIATION...06Z KGRI TAF. STRONG NORTHWEST WIND WILL BE THE
PRIMARY CONCERN FOR THE FIRST SEVERAL HOURS OF THE FORECAST...THEN
SUBSIDE SOMEWHAT BY SUNRISE...BUT CONTINUE TO BE BRISK INTO MONDAY.
CEILINGS WILL BE SCATTERING AND COULD FLUCTUATE BETWEEN VFR AND
MVFR CEILING FOR THE FIRST HOUR OR TWO AS AN AREA OF LOW PRESSURE
CONTINUES TO PULL NORTHEAST...BUT SHOULD BE PRIMARILY WITHOUT A
CEILING FROM THE GET GO.
&&
.GID WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
KS...NONE.
&&
$$
SHORT TERM...PFANNKUCH
LONG TERM...FAY
AVIATION...HEINLEIN
AREA FORECAST DISCUSSION...UPDATED
NWS NORTH PLATTE NE
1140 PM CST SUN FEB 10 2013
.UPDATE...
.DISCUSSION...
SATELLITE...SFC OBS...RADAR AND A REPORTS FROM LAW ENFORCEMENT
SUGGEST BLIZZARD CONDITIONS WILL CONTINUE FOR A FEW MORE HOURS
ACROSS THE NORTHEAST CORNER OF THE FCST AREA. THE RUC SHOWS THE
LOW LEVEL CLOUD EXITING THE FCST BY AROUND 10Z OR SO. THIS SHOULD
ALLOW FOR LESS VERTICAL MIXING AND SLOWER WIND SPEEDS.
A WINTER WEATHER ADVISORY CONTINUES OVERNIGHT FOR ALL AREAS
AFFECTED BY THE BLIZZARD. STRONG WINDS IN SOME AREAS WILL CONTINUE
TO BUILD DRIFTS AND PRODUCE NEAR WHITE OUT CONDITIONS IN SPOTS. IN
OTHER AREAS...SOME RURAL UNIMPROVED ROADS ARE PARTIALLY OR
COMPLETELY BLOCKED BY HARD PACKED DRIFTS.
&&
.PREV DISCUSSION... /ISSUED 1107 PM CST SUN FEB 10 2013/
UPDATE...
AVIATION...
FLIGHT CONDITIONS ACROSS NCNTL NEB EAST OF KVTN WILL GRADUALLY IMPROVE
FROM IFR TO VFR AS LOW CLOUDINESS EXIT EAST OVERNIGHT. VFR IS
EXPECTED ALL AREAS BY 12Z. VFR IS EXPECTED ALL AREAS THEREAFTER
THROUGH 06Z MONDAY EVENING.
PREV DISCUSSION... /ISSUED 923 PM CST SUN FEB 10 2013/
UPDATE...
DISCUSSION...
BLIZZARD CONDITIONS HAVE DECREASED WEST OF THEDFORD AND CODY. A
WINTER WEATHER ADVISORY FOR BLOWING SNOW IS NOW IN EFFECT UNTIL 8
AM CST. TRAVEL ON UNIMPROVED ROADS WILL REMAIN HAZARDOUS OVERNIGHT
DUE TO DEEP DRIFTS PARTIALLY OR COMPLETELY BLOCKING SOME ROADS.
THESE DRIFTS WILL CONTINUE TO BUILD OVERNIGHT IN SOME AREAS AS
WINDS LOCALLY CONTINUE AT SPEEDS UP TO 25 MPH.
PREV DISCUSSION... /ISSUED 717 PM CST SUN FEB 10 2013/
UPDATE...
DISCUSSION...
A QUICK FIX TO INCREASE WIND SPEEDS IN THE BLIZZARD WARNED AREA.
FCST WINDS SHOULD BE CLOSER TO THE OBSERVED SPEEDS WITH THIS UPDATE.
PREV DISCUSSION... /ISSUED 705 PM CST SUN FEB 10 2013/
UPDATE...
DISCUSSION...
SKIES HAVE CLEARED SUFFICIENTLY FOR WIND SPEEDS TO DECREASE WELL
BELOW 30 MPH ACROSS SOUTHWEST NEBRASKA WHERE THE WIND ADVISORY WAS
FLYING. THE WIND ADVISORY IS CANCELLED. NORTHWEST WINDS OF 15 TO
25 MPH ARE EXPECTED THE REST OF TONIGHT.
PREV DISCUSSION... /ISSUED 520 PM CST SUN FEB 10 2013/
UPDATE...
AVIATION...
VFR IS EXPECTED TO CONTINUE SPREADING EAST THROUGH THE FCST AREA
THIS EVENING. SIGNIFICANT WRAP AROUND SNOW AND LOW CIGS MAY
CONTINUE AROUND KONL UNTIL AROUND MIDNIGHT...PERHAPS A FEW HOURS
LATER WITH WINDS REMAINING STRONG. WINDS IN THE VFR AREA WILL
DECREASE SUBSTANTIALLY AT SUNSET WHILE ANY AREAS WITH MVFR WILL
SEE STRONG WINDS CONTINUING.
VFR IS EXPECTED ALL AREAS MONDAY.
PREV DISCUSSION... /ISSUED 351 PM CST SUN FEB 10 2013/
SYNOPSIS...
INTENSE LOW PRESSURE WAS LOCATED WEST OF SIOUX CITY IOWA THIS
AFTERNOON WITH VERY STRONG NORTHWESTERLY WINDS PRESENT ACROSS ALL OF
WESTERN AND NORTH CENTRAL NEBRASKA. WIND GUSTS WERE ON THE ORDER OF
40 TO 55 MPH THIS AFTERNOON. WITH SNOW CONTINUING IN THE CENTRAL AND
NORTHERN SANDHILLS...AS WELL AS NORTH CENTRAL NEBRASKA...BLIZZARD OR
NEAR BLIZZARD CONDITIONS CONTINUE TO PERSIST ATTM. SNOWFALL ACROSS
SOUTHWESTERN NEBRASKA HAS DIMINISHED OVER THE PAST COUPLE OF
HOURS...HOWEVER...SOME BLOWING SNOW ISSUES CONTINUE...WITH GROUND
BLIZZARD CONDITIONS CONTINUING IN KEITH AND GARDEN COUNTIES.
ELSEWHERE...ACROSS SOUTHWESTERN NEBRASKA...VSBYS WERE IN THE 1 TO 3
MILE RANGE. A PLETHORA OF WINTER HEADLINES CONTINUE ACROSS WESTERN
AND NORTH CENTRAL NEBRASKA...AND THESE WILL BE EVALUATED NEAR FCST
ISSUANCE.
SHORT TERM...(THIS EVENING THROUGH MONDAY)
990 MB SFC LOW PRESSURE CENTER IS LOCATED IN NORTHWEST IOWA AND
CONTINUES TO MOVE EAST NORTHEAST AWAY FROM THE AREA. PEAK WINDS
ARE OCCURRING NOW AND SHOULD BEGIN TO SLOWLY DIMINISH THROUGH THE
EVENING. TRAFFIC CAMS AND CALLS TO AND FROM LAW ENFORCEMENT
OFFICIALS AROUND THE REGION INDICATE THAT THE BLIZZARD WARNING CAN
BE DOWNGRADED TO A WINTER WEATHER ADVISORY ACROSS THE SOUTHERN
TIER...INCLUDING THE INTERSTATE CORRIDOR. WILL KEEP IT GOING
ACROSS NORTHERN NEBRASKA AND THE SANDHILLS...WHERE THEY ARE STILL
EXPERIENCING SOME LIGHT FALLING SNOW AND POOR VISIBILITY...DOWN TO
200 YARDS IN SOME CASES. SNOWFALL TOTALS RANGED FROM 4 TO 10
INCHES...ABOUT WHAT WAS FORECASTED. PEAK WIND SPEEDS OF 57 MPH ALSO
OCCURED. CONDTITONS SHOULD GRADUALLY IMPROVE FROM WEST TO EAST
THROGH THE NIGHT. MONDAY SHOULD SEE WINDS CONTINUE TO DIMINISH AND
SKIES CLEAR...BUT HIGH TEMPERATURES WILL BE CHILLY IN THE UPPER
20S TO MID 30S.
LONG TERM...(MONDAY NIGHT THROUGH SUNDAY)
MAIN FORECAST CHALLENGES DEAL WITH TEMPERATURES AND THE
POSSIBILITY OF LIGHT SNOW THURSDAY INTO FRIDAY. LIGHT WESTERLY
WINDS...FRESH SNOW COVER AND MOSTLY CLEAR SKIES MONDAY
NIGHT...WILL SET THE STAGE FOR COLD TEMPERATURES TUESDAY MORNING.
UNDERCUT GUIDANCE ACROSS SNOW COVERED AREAS...AND WENT WITH LOWS
NEAR ZERO IN THE PLATTE RIVER VALLEY. ON TUESDAY...AN UPPER LEVEL
TROUGH OF LOW PRESSURE WILL SLIDE EAST ACROSS THE SRN PLAINS.
PRECIPITATION AND CLOUDS ARE EXPECTED TO REMAIN SOUTH OF THE
FORECAST AREA. EVEN WITH FULL SUN...TEMPS WILL STRUGGLE TO GET OUT
OF THE HIGH 30S WITH LIGHT WINDS...SNOW COVER...AND H85 TEMPS OF
-2 TO -4 C. TEMPERATURES TUESDAY...WILL APPROACH THE LOWER 40S IN
ADVANCE OF AN APPROACHING CLIPPER SYSTEM...WHICH WILL ARRIVE ON
WEDNESDAY NIGHT. WINDY AND COLDER TEMPERATURES ARRIVE ON THURSDAY
AS A CLIPPER TRAVERSES THE EASTERN DAKOTAS AND UPPER MISSISSIPPI
VALLEY. THE MEX AND ECE GUIDANCE FEATURES A WIDE SPREAD IN TEMPS
WITH LOWER 30S NORTHEAST TO THE MIDDLE 40S IN THE SOUTHWEST.
DECIDED TO UNDERCUT THESE NUMBERS BASED ON FCST H85 TEMPS AND
RESIDUAL SNOW COVER. COLDER TEMPERATURES WILL PUSH INTO THE REGION
ON FRIDAY AS ARCTIC HIGH PRESSURE BUILDS INTO NORTHEASTERN
NEBRASKA. HIGHS FRIDAY WILL BE IN THE 20S TO THE LOWER 30S OVER
FAR SOUTHWESTERN NEBRASKA. ON SATURDAY AND SUNDAY...RIDGING WILL
BEGIN TO BUILD EAST INTO THE CENTRAL CONUS...AS A TROUGH OF LOW
PRESSURE PUSHES INTO FAR WESTERN CANADA AND THE NWRN CONUS. MORE
SEASONAL HIGHS ARE FORECAST SATURDAY AND SUNDAY WITH READINGS IN
THE 40S EXPECTED.
AVIATION...(FOR THE 18Z TAFS THROUGH 18Z MONDAY AFTERNOON)
BLOWING SNOW WILL CONTINUE THROUGH THE LATE AFTERNOON AND EARLY EVENING
HOURS AT THE KLBF TERMINAL...AND THROUGH LATE EVENING AT THE KVTN
TERMINAL...WITH VSBYS OF 3 TO 5 SM AT THE KLBF TERMINAL...AND
PERIODIC VSBYS DOWN TO 1/2 SM AT THE KVTN TERMINAL. WINDS ARE
EXPECTED TO DIMINISH AFTER 03Z TONIGHT AT THE KLBF TERMINAL AND
AFTER 06Z FOR THE KVTN TERMINAL. IN THE MEANTIME...NORTHWESTERLY
WINDS SUSTAINED AT 30 KTS...WITH GUSTS OVER 40 KTS WILL BE LIKELY
ACROSS ALL OF WESTERN AND NORTH CENTRAL NEBRASKA THROUGH EARLY THIS
EVENING. CIGS WILL RANGE FROM 1000 TO 4000 FT AGL THROUGH LATE THIS
AFTERNOON. CIGS WILL LIFT TO ABOVE 12000 FT AGL AT THE KLBF TERMINAL
BY LATE EVENING...AND TOWARD SUNRISE MONDAY AT THE KVTN TERMINAL.
&&
.LBF WATCHES/WARNINGS/ADVISORIES...WINTER WEATHER ADVISORY UNTIL 8 AM CST
/7 AM MST/ MONDAY FOR NEZ004-005-008-022>029-035>038-056-057-059-094.
BLIZZARD WARNING UNTIL 4 AM CST MONDAY FOR NEZ006-007-009-010.
&&
$$
SHORT TERM...CDC
LONG TERM...BROOKS
AVIATION....CDC
AREA FORECAST DISCUSSION
NWS HASTINGS NE
1050 PM CST SUN FEB 10 2013
.UPDATE...UPDATED THE FORECAST FOR THE EXPIRATION OF THE WIND AND
WINTER WEATHER ADVISORIES AS WIND HAS GENERALLY DECREASED
SOME...BUT WE COULD GET SOME HEALTHY GUSTS WELL INTO THE
OVERNIGHT. TWEAKED UP HOURLY TEMPERATURES A BIT WITH THE INCREASED
WIND SPEED AND ALSO ADDED SOME FLURRIES OVER THE NORTHEASTERN
THIRD FOR THE OVERNIGHT AS THE MOSAIC RADAR LOOP INDICATES.
&&
.AVIATION...06Z KGRI TAF. STRONG NORTHWEST WIND WILL BE THE
PRIMARY CONCERN FOR THE FIRST SEVERAL HOURS OF THE FORECAST...THEN
SUBSIDE SOMEWHAT BY SUNRISE...BUT CONTINUE TO BE BRISK INTO MONDAY.
CEILINGS WILL BE SCATTERING AND COULD FLUCTUATE BETWEEN VFR AND
MVFR CEILING FOR THE FIRST HOUR OR TWO AS AN AREA OF LOW PRESSURE
CONTINUES TO PULL NORTHEAST...BUT SHOULD BE PRIMARILY WITHOUT A
CEILING FROM THE GET GO.
&&
PREV DISCUSSION... /ISSUED 259 PM CST SUN FEB 10 2013/
SHORT TERM...TODAY THROUGH MONDAY NIGHT. MAIN CONCERN DURING
THIS TIME PERIOD WILL BE THE WINDS BEHIND THE SURFACE LOW. OUR
NORTHERN COUNTIES...WHERE SNOWFALL OCCURRED EARLIER TODAY...WILL
LIKELY RUN INTO VISIBILITY RESTRICTIONS AS BLOWING SNOW OCCURS
THROUGH THE EARLY EVENING HOURS. ORD HAS EXPERIENCED VISIBILITIES
BETWEEN ONE AND TWO MILES SINCE ABOUT 18Z TODAY...BUT EARLIER
TODAY CONDITIONS WERE BELOW HALF A MILE. ALSO...THERE WILL BE A
SLIGHT CHANCE FOR SNOW THROUGH THE REMAINDER OF TODAY...MAINLY FOR
OUR NORTHERN COUNTIES.
AT 20Z...THE RAP INDICATED A 500MB LOW APPROXIMATELY CENTERED
OVER SIOUX FALLS SOUTH DAKOTA. THE SURFACE LOW WAS DIRECTLY UNDER
THE UPPER LEVEL LOW...RESULTING IN A STACKED TROUGH WHICH IS NOW
EXITING THE CENTRAL PLAINS. BEHIND THE SURFACE LOW...HEIGHT RISES
ARE RESULTING IN A SHARP PRESSURE GRADIENT OVER THE OUTLOOK AREA.
NORTHWESTERLY WIND SPEEDS OF 30 MPH WERE EXPERIENCED OVER NEARLY
THE ENTIRE CWA. GUSTS WERE REACHING THE MID TO UPPER 40S...WITH
ONLY A COUPLE SITES REACHING 50 MPH. THE WINTER WEATHER ADVISORY
FOR BLOWING SNOW WILL CONTINUE UNTIL 9 PM TONIGHT TONIGHT. THIS
WILL LIKELY NEED TO BE CONVERTED TO A WIND ADVISORY IF
VISIBILITIES RECOVERY LATER TODAY. THE WIND ADVISORY COUNTIES
UNTIL 9 PM...AS MODELS ARE NOT DEPICTING ANY LETTING UP OF THE
PRESSURE GRADIENT BEFORE THEN. THE WIND ADVISORY MAY NEED TO BE
EXTENDED FOR OUR EASTERN COUNTIES IF CONDITIONS DO NO EASE UP
LATER TONIGHT.
WIND SPEEDS WILL BEGIN TO RELAX AFTER MIDNIGHT AS THE PRESSURE
GRADIENT EASES OVER THE REGION. A NORTHWESTERLY WIND COMPONENT WILL
BE REALIZED OVER THE ENTIRE SHORT TERM PERIOD.
HIGH TEMPERATURES FOR TOMORROW WILL BE RELATIVELY CLOSE TO NORMAL
FOR THIS TIME OF YEAR. ON THE OTHER HAND...LOW TEMPERATURES WILL BE
SLIGHTLY ABOVE NORMAL FOR THIS TIME OF YEAR.
LONG TERM...MONDAY NIGHT THROUGH SUNDAY...WEAK ZONAL FLOW IS
EXPECTED ACROSS THE REGION TO BEGIN THE EXTENDED PERIODS AS THE
VIGOROUS UPPER LEVEL LOW THAT MOVED ACROSS THE LOCAL AREA THIS
MORNING APPROACHES THE EASTERN SEABOARD AND A SECOND UPPER LEVEL
LOW TRACKS ACROSS THE DESERT SOUTHWEST. AT THE SAME TIME A WEAK
UPPER LEVEL SHORTWAVE IS EXPECTED TO EXTEND ACROSS THE LOCAL AREA
FROM THE NORTH...PROVIDING AMPLE MID LEVEL CLOUD COVER DURING THE
OVERNIGHT HOURS MONDAY INTO TUESDAY MORNING...BUT WITH MINIMAL
FORCING AND VERY LIMITED LOW LEVEL MOISTURE...DO NO EXPECT ANY
SORT OF PRECIPITATION UNDER THIS SCENARIO.
AS THE AFOREMENTIONED UPPER LEVEL ACROSS THE DESERT SOUTHWEST
MOVES INTO THE SOUTHERN PLAINS TUESDAY AFTERNOON...THE UPPER
LEVEL FLOW PATTERN WILL BECOME MORE AMPLIFIED...AS A RIDGE OF HIGH
PRESSURE WORKS ITS WAY TOWARDS THE WEST COAST. THIS WILL ESTABLISH
A NORTHWESTERLY FLOW ALOFT ACROSS THE NORTHERN AND CENTRAL PLAINS
BY WEDNESDAY...WITH MULTIPLE QUICK PASSING UPPER LEVEL
DISTURBANCES EXPECTED TO TRAVERSE THE PLAINS. WITH THE QUICK
MOVING NATURE OF THESE DISTURBANCES AND DRY LOW LEVELS OF THE
ATMOSPHERE...DO NOT THINK MORE THAN FLURRIES WILL BE REALIZED
THROUGH THE END OF THE WEEK...WITH THE BEST GUEST AT TIMING BEING
DURING THE DAY ACROSS THE NORTHWEST THURSDAY...AND ACROSS ALL
AREAS ON FRIDAY. THE FIRST OF THESE DISTURBANCE WILL BE
ACCOMPANIED BY A SURFACE COLD FRONT...WHICH IS EXPECTED TO KNOCK
TEMPERATURES DOWN 10+ DEGREES F ON THURSDAY...WITH THIS
COOLER...YET SEASONAL AIRMASS THEN EXPECTED TO PERSIST ACROSS THE
LOCAL ARE THROUGH THE END OF THE WEEK. AHEAD OF THE
FRONT...WEDNESDAY AFTERNOON APPEARS TO BE THE NICEST DAY OF THE
WEEK...WITH A LIGHT DOWNSLOPING COMPONENT TO THE WINDS LIKELY
HELPING TEMPERATURES CLIMB TO NEAR 50 DEGREES.
&&
.GID WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
KS...NONE.
&&
$$
UPDATE/AVIATION...HEINLEIN
AREA FORECAST DISCUSSION...UPDATED
NWS ALBUQUERQUE NM
457 AM MST MON FEB 11 2013
.AVIATION...
12Z TAF CYCLE
A CHALLENGING DAY LIKELY FOR AVIATION AS TWO SURFACE FRONTS AND AN
UPPER LEVEL LOW CONVERGE OVER THE AREA. CONFIDENCE ON THE TIMING
OF THE MAIN IMPACT FEATURES IS MODERATE AS VARIOUS SHORT-TERM MODEL
GUIDANCE IS STILL CONFLICTING. THE LATEST RUC AND HRRR SUGGEST A
RATHER POTENT SNOW BAND WILL SLIDE EAST TODAY MUCH EARLIER THAN THE
MET/MAV MOS GUIDANCE...SO HAVE DECIDED TO BRING IN THE FEATURE OVER
CENTRAL NM FOR KABQ/KSAF FASTER THAN PREVIOUS TAFS. POTENTIAL FOR
A SHORT DURATION OF IFR IS HIGH FOR SITES THAT ARE IMPACTED BY THIS
BAND. WINDS WILL SHIFT DRAMATICALLY TO THE WEST AND NW WITH THIS
FRONT...THEN DIMINISH DURING THE EVENING WHILE -SHSN LINGER OVER
CENTRAL/WESTERN NM. MEANWHILE ACROSS THE EAST RETURN EASTERLY FLOW
WILL INCREASE MOISTURE AND LOWER MID LEVEL CLOUD DECKS AFT 00Z.
MODERATE TO LCL HEAVY SN IS EXPECTED AFT SUNSET WITH MUCH LONGER
DURATION IMPACTS FOR KLVS/KTCC OVERNIGHT. GUYER
&&
.PREV DISCUSSION...338 AM MST MON FEB 11 2013...
AN UPPER TROUGH THAT DUG DEEPLY THROUGH UT ON SUNDAY APPEARS TO
BE FORMING A CLOSED LOW PRESSURE CIRCULATION AS IT DROPS INTO
NORTHERN AZ EARLY THIS MORNING. MODELS AGREE THAT THIS FEATURE WILL
PASS EASTWARD OVER NM ALONG AND A LITTLE NORTH OF INTERSTATE 40
TONIGHT...THEN IT WILL EXIT GRADUALLY EASTWARD THROUGH THE TX
PANHANDLE ON TUESDAY. STEADY SNOW THAT HAS BEEN FALLING ON THE
WEST SLOPE OF THE CO ROCKIES SHOULD DROP SOUTHWARD INTO NW NM TODAY
AND EXTEND SOUTHWARD ALONG THE NM CONTINENTAL DIVIDE. A COLD
FRONT WILL PROVIDE A FOCUS FOR PRECIP AS IT PUSHES SOUTHEASTWARD
THROUGH WESTERN NM TODAY...THEN THROUGH CENTRAL PARTS OF THE STATE
THIS EVENING...AND THROUGH THE PLAINS EARLY TUESDAY MORNING. FOR
WESTERN AND CENTRAL AREAS WE WILL CONTINUE WITH ONGOING HEADLINES
FOR SNOW...BUT WILL UPGRADE THE JEMEZ MOUNTAINS AND UPPER RIO
GRANDE VALLEY TO A WINTER STORM WARNING BASED ON THE TRACK OF THE
LOW AND THE LATEST MODEL SNOW AMOUNTS. WILL ALSO ISSUE A WINTER
WEATHER ADVISORY FOR THE WEST CENTRAL HIGHLANDS...SANTA FE METRO
AREA AND LOWER CHAMA RIVER VALLEY FOR TONIGHT. LIKE THE JEMEZ AND
UPPER RIO GRANDE VALLEY...THESE AREAS SHOULD SEE A PERIOD OF
MODERATE TO HEAVY SNOW THIS EVENING AS THE COLD FRONT CROSSES
FROM THE WEST...THEN SOME LINGERING SNOW LATE TONIGHT AS THE
UPPER LOW CROSSES.
ASIDE FROM THE WESTERLY UPSLOPE FLOW EVENT ALONG AND WEST OF THE
CENTRAL MOUNTAIN CHAIN...AN EASTERLY UPSLOPE EVENT IS EXPECTED EAST OF
THE SANGRE DE CRISTOS TONIGHT. THEN...WRAP AROUND MOISTURE WILL
KEEP SNOW FALLING ACROSS THE EAST CENTRAL AND NORTHEAST PLAINS ON
TUESDAY. THE 00Z GFS AND NAM BOTH DEPICT WARNING CRITERIA SNOW
AMOUNTS ACROSS THE PLAINS...BUT THE ECMWF HAS LIGHTER AMOUNTS
DESPITE THE SAME COVERAGE AREA OF PRECIP. GIVEN THIS
UNCERTAINTY...WE OPTED TO EXPAND THE WINTER STORM WATCH FOR NE NM
SOUTHEASTWARD ACROSS QUAY...CURRY AND ROOSEVELT COUNTIES.
ALSO...MODEL AGREEMENT ON THE TRACK OF THE LOW AND EASTERLY
UPSLOPE FLOW OVERNIGHT GAVE US ENOUGH CONFIDENCE TO UPGRADE THE
WINTER STORM WATCH TO A WARNING FOR THE EAST SLOPES OF THE SANGRES
AND RATON PASS.
UNCERTAINTY REMAINS ABOUT HOW MUCH SNOW WILL FALL ACROSS CENTRAL
AND SE NM. MODELS AGREE ON SURPRISINGLY LIGHT QPF AROUND ABQ...THE
SANDIAS AND THE CENTRAL HIGHLANDS. THEY TYPICALLY DONT RESOLVE THE
NARROW SANDIA AND MANZANO MOUNTAINS VERY WELL...AND THESE RANGES
TEND TO WRING OUT SNOW AS COLD FRONTS CROSS FROM THE WEST...SO WE
ARE ALSO ISSUING A WINTER WEATHER ADVISORY FOR THE SANDIAS AND
MANZANOS WITH THIS MORNINGS FORECAST PACKAGE. WILL LET THE DAY
SHIFT DECIDE WHAT TO DO WITH THE ALBUQUERQUE METRO AREA AND
CENTRAL HIGHLANDS...SINCE MODELS AGREE ON LIGHTER PRECIP IN THESE
AREAS...PERHAPS TOO LIGHT FOR ANY HEADLINES.
PRECIP WILL TAPER OFF QUICKLY LATE TUESDAY AFTERNOON. AFTER HIGH
TEMPERATURES 12 TO 20 DEGREES BELOW NORMAL ON TUESDAY...TEMPERATURES
WILL WARM BUT REMAIN BELOW NORMAL UNDER DRY NW FLOW ALOFT
WEDNESDAY. AN UPPER TROUGH WILL DIVE SOUTHEASTWARD ALONG THE FRONT
RANGE OF THE ROCKIES THURSDAY THROUGH FRIDAY. THE POTENTIAL
EXISTS FOR A FEW INCHES OF SNOW ACCUMULATION ALONG AND EAST OF THE
NORTHERN AND CENTRAL MOUNTAINS MAINLY THURSDAY NIGHT AND FRIDAY. 44
.FIRE WEATHER...
AN ACTIVE WX SCENARIO WILL CONTINUE THRU THIS WEEK WITH BOUTS OF
SNOW...COLD...AND WIND...THEN MILDER TEMPS AND DRY BREEZY CONDITIONS
OVER THE WEEKEND. THE PACIFIC COLD FRONT AND ASSOCIATED SNOW BAND IS
POSITIONED OVER AZ AND FAR WESTERN NM...WHILE THE PLAINS FRONT IS
BACKING INTO THE NE CORNER. AN UPPER LEVEL WAVE WILL SLIDE OVER
THESE TWO FRONTS AS THEY CONVERGE OVER NM ALLOWING FOR WIDESPREAD
SNOW FIRST OVER THE WEST TODAY/TONIGHT THEN OVER THE EAST TONIGHT/
TUESDAY. MUCH NEEDED ADDITIONAL SNOW ACCUMS OVER THE HIGHER TERRAIN
WILL CONTINUE ADDING TO OUR BELOW NORMAL SNOWPACK.
TEMPS WILL BE COLD WITH THIS WINTER SYSTEM BOTH TODAY AND TUESDAY...
WITH SLIGHTLY MILDER CONDITIONS FOR WEDNESDAY. MIN RH VALUES WILL
BE QUITE HIGH AS A RESULT OF THE SNOW MONDAY/TUESDAY AS WELL AS
WEDNESDAY DESPITE VERY DRY AIR WORKING INTO THE REGION BEHIND THE
WAVE. WIDESPREAD VERY GOOD TO EXCELLENT MAX RH RECOVERIES ARE ALSO
ON TAP. VENT RATES WILL START OUT VERY GOOD TO EXCELLENT TODAY FOR
CENTRAL NM WITH SW FLOW AHEAD OF THE WAVE...DECREASE TUESDAY...THEN
BECOME POOR AREAWIDE BY WEDNESDAY AS WINDS ALOFT WEAKEN.
ANOTHER WAVE WILL SLIDE SOUTH OVER THE AREA THURSDAY AND REINFORCE
THE COLD AIR AND INCREASE LOW LEVEL MOISTURE ONCE AGAIN. MODELS
DISAGREE ON PRECIP DEVELOPMENT OVER THE NORTHEAST WITH THIS SYSTEM.
A RIDGE IS THEN ANTICIPATED TO MOVE SLOWLY OVER THE REGION LATE
FRIDAY INTO THE WEEKEND. STRONG TEMP INVERSIONS WILL BE GREATEST
FRIDAY AND SATURDAY MORNING...LEADING TO POOR VENT RATES. BREAK DOWN
OF THIS RIDGE SUNDAY/MONDAY MAY LEAD TO CRITICAL FIRE WX CONDITIONS
FOR EASTERN NM IN ASSOCIATION WITH A MID LEVEL DRY SLOT. GUYER
&&
.ABQ WATCHES/WARNINGS/ADVISORIES...
WINTER STORM WATCH FROM THIS EVENING THROUGH TUESDAY AFTERNOON FOR
THE FOLLOWING ZONES...NMZ528>532-534>536.
WINTER WEATHER ADVISORY FROM 6 PM THIS EVENING TO 6 AM MST TUESDAY
FOR THE FOLLOWING ZONES...NMZ507-517-518-521.
WINTER WEATHER ADVISORY UNTIL 6 AM MST TUESDAY FOR THE FOLLOWING
ZONES...NMZ501-504>506.
WINTER STORM WARNING UNTIL 6 AM MST TUESDAY FOR THE FOLLOWING
ZONES...NMZ502-503-510>516-527.
&&
$$
AREA FORECAST DISCUSSION
NWS BUFFALO NY
448 AM EST MON FEB 11 2013
.SYNOPSIS...
AN AREA OF LOW PRESSURE WILL MOVE INTO SOUTHERN QUEBEC TODAY. THIS
WILL BRING A PERIOD OF RAIN EARLY TODAY...WITH SOME FREEZING
RAIN ACROSS THE INTERIOR VALLEYS AND A WINTRY MIX EAST OF LAKE
ONTARIO. AFTER THIS WINDS WILL INCREASE BEHIND AN ASSOCIATED COLD
FRONT...CAUSING RAIN SHOWERS TO CHANGE TO SNOW LATER TODAY AND
TONIGHT.
&&
.NEAR TERM /THROUGH TONIGHT/...
THERE WILL BE SEVERAL TRANSITIONS TODAY...AS A SERIES OF BOUNDARIES
ASSOCIATED WITH LOW PRESSURE ACROSS THE UPPER LAKES INFLUENCES OUR
WEATHER.
THROUGH THIS MORNING...THE MAIN SOURCE OF LIFT WILL COME FROM AN
AREA OF WARM AIR ADVECTION ALOFT. RADAR TRENDS SUGGEST STEADIEST
RAINS WILL FOCUS NORTH OF A BUFFALO TO ROCHESTER LINE...WITH LIGHTER
QPFS ACROSS THE SOUTHERN TIER. FORTUNATELY...TEMPERATURES SHOULD
REMAIN JUST ABOVE FREEZING IN THESE LOCATIONS...WITH DOWNSLOPING
OFFSETTING EVAPORATIONAL COOLING. A FREEZING RAIN ADVISORY REMAINS
IN EFFECT ACROSS THE INTERIOR...WHERE TEMPERATURES AT 400 AM ARE IN
THE LOWER TO MID 30S. HOWEVER...WITH DEW POINTS IN THE 20S EXPECT
EVAPORATIONAL COOLING TO DROP TEMPERATURES A FEW DEGREES AS THE RAIN
STARTS. RADAR TRENDS ARE MUCH BETTER CAPTURED BY THE HRRR THAN THE
NAM/GFS/RGEM WHICH ARE TOO HIGH ON QPF ACROSS THE SOUTHERN TIER. FOLLOWING
THIS...EXPECT A FEW HUNDREDTHS OF AN INCH OF QPF ACROSS INTERIOR
PORTIONS OF WESTERN NEW YORK...HOWEVER THIS WILL FALL AS FREEZING
RAIN IN MANY SPOTS...SO WILL KEEP THE ADVISORY UP. STEADIER
PRECIPITATION WILL MOVE EAST OF LAKE ONTARIO THROUGH
DAYBREAK...BRINGING THE GREATEST ICING POTENTIAL FOR THIS EVENT.
THERE WILL BE MODEST DOWNSLOPE WARMING HERE TOO...BUT WITH DRY AND
COOLER AIR IN PLACE EXPECT AROUND A TENTH OF AN INCH OF FREEZING
RAIN GLAZE...WITH PERHAPS SOME LIGHT SNOW OR SLEET ACCUMULATION.
ALL OF THIS PRECIPITATION SHOULD LIFT FROM SW- NE...ENDING ACROSS
WESTERN PORTIONS AROUND DAYBREAK...AND LATE THIS MORNING EAST OF
LAKE ONTARIO. THIS SHOULD PROVIDE A BRIEF LULL IN THE ACTION UNTIL
THE NEXT BOUNDARY CROSSES.
THE NEXT PHASE OF THIS EVENT WILL COME AS THE COLD/OCCLUDED FRONT ASSOCIATED
WITH THE UPPER LOW MOVES ACROSS THE REGION. IT WILL ENTER
WESTERN NEW YORK AROUND NOON...SWEEPING TO EAST OF LAKE ONTARIO
AROUND SUNSET. THIS WILL BRING MAINLY SCATTERED RAIN SHOWERS...BUT
ITS MORE SIGNIFICANT IMPACT WILL BE AN INCREASE IN WINDS BEHIND
IT. GUSTY SOUTHWESTERLY WINDS WILL PICK UP FIRST ACROSS THE
NIAGARA FRONTIER...SPREADING TO THE EAST LATE AFTERNOON AND
EVENING. THE LOW IS NOT PARTICULARLY DEEP...NOR IS THE COLD
ADVECTION TOO STRONG. WITH ONLY MODEST PRESSURE RISES DONT EXPECT
EXTREMELY DEEP MIXING TO TAP THE 50 KNOTS ALOFT...BUT STILL
SUFFICIENT TO BRING ADVISORY CRITERIA GUSTS OF 45 TO 50 MPH LATER
IN THE AFTERNOON. THE 230-240 DEGREE WIND DIRECTION FAVORS THE
STRONGER WINDS FROM THE LAKE ERIE SHORE ACROSS THE NIAGARA
FRONTIER TO ROCHESTER. LATER IN THE EVENING WINDS BECOME MORE
WESTERLY...WHICH WILL SPREAD STRONGER WINDS INTO THE INTERIOR
SOUTHERN TIER AND WESTERN FINGER LAKES. A WIND ADVISORY REMAINS IN
EFFECT ACROSS ALL BUT THE EASTERN LAKE ONTARIO REGION.
BEHIND THE COLD FRONT...THE UPPER LEVEL TROF ASSOCIATED WITH THE LOW
WILL MOVE ACROSS THE REGION. THIS WILL USHER IN COLDER AIR BOTH
ALOFT AND AT THE SURFACE. ITS IMPORTANT TO NOTE THAT THIS IS NOT A
VERY COLD AIR MASS...WITH 850 MB TEMPERATURES LIKELY TO DROP TO
AROUND -10C TONIGHT. THIS IS NOT REALLY COLD ENOUGH FOR PURE LAKE
EFFECT...BUT WITH SIGNIFICANT MOISTURE ASSOCIATED WITH THE UPPER
TROF...AND SOME UPSLOPE ENHANCEMENT...EXPECT THERE WILL BE SOME SNOW
EAST AND NORTHEAST OF THE LAKES TONIGHT. GIVEN THE MINIMAL
CONTRIBUTION FROM LAKE INSTABILITY...EXPECT QPFS ARE A BIT OVERDONE
BY THE NAM/RGEM WITH THE UPSLOPE...BUT DO FEEL SOME PRECIPITATION IS
CERTAINLY REASONABLE. SNOW RATIOS SHOULD NOT BE GREAT GIVEN THE
MARGINALLY COLD AIR...WITH 2 OR 3 INCHES SNOW ACCUMULATION LIKELY ON
THE TUG HILL TONIGHT...AND A BIT LESS ON THE CHAUTAUQUA RIDGE. IF
THERE WERE NOT ALREADY ADVISORIES IN PLACE...THIS PORTION OF THE
EVENT COULD REQUIRE A SNOW ADVISORY...BUT WITH A BREAK BETWEEN THE
TWO WILL HANDLE THIS AS TWO EVENTS RATHER THAN COMPLICATING THE
ISSUE. THIS IS A CHALLENGING EVENT...BECAUSE IF MODEL QPF DOES
VERIFY OR IF SNOW RATIONS EXCEED 20 TO 1...THEN THIS COULD ACTUALLY
APPROACH WARNING CRITERIA ON THE TUG HILL. AT THIS TIME...NEITHER OF
THESE SCENARIOS APPEAR LIKELY. SNOWS WILL BE LESS OFF LAKE ERIE...BUT
THE SW FLOW MAY BRING AN INCH OR SO ACROSS THE BUFFALO METRO
AREA...WITH LOCALLY HIGHER AMOUNTS ACROSS THE BOSTON HILLS AND
CHAUTAUQUA RIDGE.
OTHERWISE...TEMPERATURES WILL WARM BRIEFLY TODAY...ESPECIALLY IN THE
FINGER LAKES REGION...WITH HIGHS IN THE 40S AHEAD OF THE FRONT.
WINDS WILL BE GUSTY FOR A FEW HOURS THROUGH DAYBREAK ALONG I-90 FROM
THE NY/PA LINE TO BUFFALO AS DOWNSLOPING RESULTS IN GUSTS UP TO 40
MPH. 925 MB WINDS WILL DIMINISH AFTER 12Z...DIMINISHING WINDS HERE
UNTIL THE FRONT MOVES THROUGH.
&&
.SHORT TERM /TUESDAY THROUGH WEDNESDAY NIGHT/...
ON TUESDAY A SURFACE COLD FRONT WILL BE WELL TO THE EAST WITH COLD
AIR ADVECTING ACROSS THE EASTERN GREAT LAKES. THIS WILL BE A
MARGINAL SET UP FOR LAKE EFFECT SNOW...WITH THE MAIN FORCING
MECHANISM BEING MORE THE UPSLOPE FLOW OVER HIGHER TERRAIN EAST OF
BOTH GREAT LAKES.
TEMPERATURES AT 850 HPA WILL DROP TO AROUND -10C THROUGH THE DAY
TUESDAY WHICH CREATES VERY LITTLE INSTABILITY OFF LAKE ERIE...AND
ONLY MINOR LAKE INSTABILITY OFF LAKE ONTARIO. WHILE THERE WILL BE
PLENTY OF MOISTURE IN THE LOWER LEVELS...DRIER AIR BEHIND AN UPPER
LEVEL SHORTWAVE WILL LOWER THIS MOISTURE TO JUST BELOW THE SNOW
CRYSTAL GROWTH ZONE...AND WITH WEAK UPWARD OMEGA FORCING THERE WILL
NOT BE GOOD SNOW CRYSTAL GROWTH. WILL CONTINUE WITH LIKELY POPS
ACROSS THE HIGHER TERRAIN SOUTH OF BUFFALO...AND CATEGORICAL POPS
EAST OF LAKE ONTARIO WHERE LAKE ENHANCEMENT TO THE UPSLOPE SNOW
SHOWERS SHOULD BRING SEVERAL INCHES DURING THE DAY TUESDAY. ANOTHER
WEAK SHORTWAVE WILL CROSS WNY TUESDAY AND THIS WILL KEEP LOW CHANCE
POPS FOR A SNOW SHOWER EVEN ACROSS THE LOWER ELEVATIONS. THIS
SHORTWAVE WILL ALSO CAUSE LAKE ENHANCEMENT TO BE TRANSITORY THROUGH
THE DAY. A WINTER WEATHER ADVISORY MAY BE NEEDED FOR THIS SNOW EVENT
FOR THE TUG HILL REGION CONTINUING INTO TUESDAY...AND TUESDAY NIGHT.
HOWEVER WITH A CURRENT WINTER WEATHER ADVISORY ALREADY IN PLACE WILL
JUST MENTION THE PROSPECTS FOR ADVISORY LEVEL SNOWS IN THE HWO.
HIGHS ON TUESDAY WILL NOT CLIMB TOO MUCH FROM THEIR MORNING
LOWS...WITH TEMPERATURES THROUGH THE DAY LARGELY IN THE LOW TO MID
30S. WINDS WILL CONTINUE TO BE GUSTY THROUGH THE MORNING HOURS BUT
AS THE SURFACE LOW CARRIES FARTHER EASTWARD THROUGH ATLANTIC CANADA
AND WINDS ALOFT WEAKEN THE GUSTY SURFACE WINDS SHOULD DIMINISH
THROUGH THE DAY.
TUESDAY NIGHT SOME DRIER AIR BEGINS TO FILTER ACROSS THE GREAT
LAKES...YET THERE SHOULD STILL BE ENOUGH MOISTURE TO MAINTAIN THESE
SNOW SHOWERS...ESPECIALLY EAST OF LAKE ONTARIO. WITH THE FLOW VEERING
A LITTLE THE SNOW SHOWERS ACROSS THE EASTERN LAKE ONTARIO REGION
WILL BE MORE FOCUSED UPON OSWEGO AND SOUTHERN LEWIS COUNTIES.
WEDNESDAY FURTHER DRYING ALOFT AND WARM AIR ADVECTION WILL BRING AN
END TO THE WEAK LAKE ENHANCED SNOW SHOWERS EAST OF LAKE ONTARIO.
EXPECT JUST A CHANCE FOR MORNING LAKE EFFECT SNOW...CARRYING
NORTHWARD AND WEAKENING TO FLURRIES JUST SOUTH OF WATERTOWN. HIGH
PRESSURE WILL CROSS OUR REGION...CENTERED TO OUR SOUTH...AND WITH
THE AXIS OF A WEAK UPPER LEVEL RIDGE CROSSING THE EASTERN GREAT
LAKES WE SHOULD SEE ADDITIONAL SUNSHINE THROUGH THE DAY. CLOUDS WILL
BEGIN TO THICKEN FROM THE SOUTH WEDNESDAY AFTERNOON AND EVENING WELL
AHEAD OF A STORM SYSTEM CROSSING THE SOUTHEAST. A PRIMARY SURFACE
LOW WILL TRACK TO ABOUT WESTERN PENNSYLVANIA BEFORE AN UPPER LEVEL
SHORTWAVE TROUGH TRANSFERS ENERGY TO A DEVELOPING COASTAL LOW THAT
WILL QUICKLY DEEPEN. IT LOOKS LIKE THIS SYSTEM WILL MISS OUR
AREA...WITH JUST A SLIGHT CHANCE THAT SOME LIGHT SNOW WILL BRUSH BY
THE UPPER GENESEE RIVER VALLEY EARLY WEDNESDAY NIGHT. WITH THE WARM
AIR ADVECTION ALOFT AND WINDS FROM THE SOUTHEAST HIGHS WEDNESDAY
WILL CLIMB SEVERAL DEGREES WARMER THAN TUESDAY. HIGHS ON WEDNESDAY
WILL CLIMB INTO THE MID AND UPPER 30S WITH A SPOT 40 POSSIBLE.
&&
.LONG TERM /THURSDAY THROUGH SUNDAY/...
DURING THIS PERIOD...GFS/ECMWF FEATURE THE DEVELOPMENT OF A HIGH
AMPLITUDE RIDGE OVER THE WESTERN UNITED STATES AND A LARGE BROAD
TROUGH OVER THE EASTERN 2/3 OF THE U.S FROM THE COLORADO ROCKIES TO
THE EASTERN SEA BOARD. INITIALLY...TEMPERATURES WILL START OUT
SLIGHTLY ABOVE CLIMATOLOGY AND THEN ARE FORECAST TO GRADUALLY TREND
COLDER THROUGH THE WEEKEND SATURDAY TO SUNDAY.
A CLIPPER-TYPE LOW PRESSURE SYSTEM WILL SET THE STAGE...IT IS
FORECAST TO TRACK JUST TO THE WEST OF THE REGION ACROSS THE UPPER
GREAT LAKES. SOUTHERLY WINDS AHEAD OF THIS SYSTEM WILL PICK UP
ACROSS THE REGION..THEN A COLD FRONT WILL CROSS WESTERN AND NORTH
CENTRAL NEW YORK THURSDAY NIGHT INTO FRIDAY...BRINGING WITH IT A
CHANCE OF RAIN AND SNOW SHOWERS. COLDER AIR FOLLOWING THIS SYSTEM
WILL BRING A CHANCE FOR MORE SNOW SHOWERS AND POSSIBLE LAKE EFFECT
SNOW FRIDAY NIGHT AND SATURDAY. HOWEVER...THERE ARE DIFFERENCES
BETWEEN THE GFS/ECMWF WITH TIMING AND THE GENERAL STRENGTH OF THE
CLIPPER-TYPE SYSTEM FORECAST TO MOVE ACROSS THE REGION. AT THIS
POINT...IT SEEMS LIKELY THAT WESTERN/NORTH CENTRAL NY WILL SEE A
GRADUAL RETURN TO COLDER TEMPERATURES OVER THE PERIOD.
&&
.AVIATION /10Z MONDAY THROUGH FRIDAY/...
STEADIEST PRECIPITATION WILL LIFT ACROSS THE REGION FROM
W-E THROUGH 15Z. EXPECT A COUPLE HOURS OF LIGHT RAIN AT MOST TAF
SITES...WITH SOME -FZRA AT JHW/ART WHERE TEMPERATURES WILL BE A
BIT COOLER. DOWNSLOPING SHOULD KEEP CIGS MVFR OR HIGHER AT MOST
TAF LOCATIONS...BUT A PERIOD OF IFR OR LOWER CIGS IS LIKELY AT JHW
WHICH DOES NOT DRY AS WELL IN THIS TYPE OF FLOW.
PRECIPITATION WILL END LATE THIS MORNING...PROVIDING A BRIEF BREAK
BEFORE THE NEXT ROUND OF SHOWERS MOVES IN THIS AFTERNOON. THERE
STILL MAY BE LINGERING MOISTURE AND MVFR CIGS AHEAD OF THE COLD
FRONT. SHOWERS WILL EVENTUALLY TRANSITION TO SNOW SHOWERS AS
COLDER AIR WORKS IN.
BESIDES THE RISK OF MIXED WINTRY PRECIPITATION...THERE
WILL BE SOME LOW LEVEL WIND SHEAR TO CONTEND WITH THIS MORNING. WINDS
AT 1500-2000 FT WILL AVERAGE 40-50 KTS WHILE SFC WINDS WILL BE IN
THE VCNTY OF 10 KNOTS. BY THIS AFTERNOON...THE STRONGER WINDS
ALOFT SHOULD BE AT LEAST PARTIALLY MIXING TO THE SFC. WIND GUSTS
OVER 30 KTS WILL BE POSSIBLE AT KIAG AND KBUF LATER IN THE
AFTERNOON.
TONIGHT...MVFR CONDITIONS WILL BE LIKELY WITH VSBYS BEING LOWERED
IN SNOW SHOWERS. THE MOST WIDESPREAD SNOWS WILL BE GENERATED EAST
OF BOTH LAKES WHERE IFR CONDITIONS WILL BE POSSIBLE.
OUTLOOK...
TUESDAY...MVFR/IFR IN LIGHT SNOW SHOWERS.
WEDNESDAY AND THURSDAY...MAINLY VFR.
FRIDAY...MVFR/IFR WITH A CHANCE OF SNOW.
&&
.MARINE...
SOUTHERLY WINDS WILL BE GUSTY THIS MORNING...ESPECIALLY ON LAKE
ERIE...AS STRONG WINDS ALOFT OCCASIONALLY MIX DOWN. AFTER
THIS...EXPECT A BIT OF LULL...BEFORE A COLD FRONT CROSSES THE WATERS
AROUND MIDDAY. THIS WILL SHIFT WINDS TO THE SOUTHWEST AND CAUSE AN
INCREASE TO 35 KNOT GALES BEHIND THE FRONT. EXPECT GALES TO CONTINUE
THROUGH TONIGHT...GRADUALLY SUBSIDING FROM WEST TO EAST ON TUESDAY.
HIGH PRESSURE WILL BUILD ACROSS THE REGION WEDNESDAY...WITH NO
HEADLINES ANTICIPATED.
&&
.BUF WATCHES/WARNINGS/ADVISORIES...
NY...FREEZING RAIN ADVISORY UNTIL 8 AM EST THIS MORNING FOR NYZ004-
005-012>014-019>021-085.
WIND ADVISORY FROM 1 PM THIS AFTERNOON TO 5 AM EST TUESDAY FOR
NYZ001>003-010>012-019-085.
WINTER WEATHER ADVISORY UNTIL NOON EST TODAY FOR NYZ007-008.
FREEZING RAIN ADVISORY UNTIL 10 AM EST THIS MORNING FOR NYZ006.
WIND ADVISORY FROM 6 PM THIS EVENING TO 5 AM EST TUESDAY FOR
NYZ004-013-014-020-021.
MARINE...SMALL CRAFT ADVISORY UNTIL 1 PM EST THIS AFTERNOON FOR LEZ040-
041.
GALE WARNING FROM 1 PM THIS AFTERNOON TO 4 AM EST TUESDAY
FOR LEZ020-040-041.
GALE WARNING FROM 1 PM THIS AFTERNOON TO 10 AM EST
TUESDAY FOR LOZ042-043-062-063.
SMALL CRAFT ADVISORY UNTIL 4 PM EST THIS AFTERNOON FOR
LOZ045.
GALE WARNING FROM 4 PM THIS AFTERNOON TO 1 PM EST TUESDAY
FOR LOZ044-045-064-065.
&&
$$
SYNOPSIS...APFFEL
NEAR TERM...APFFEL
SHORT TERM...THOMAS
LONG TERM...AR
AVIATION...APFFEL
MARINE...APFFEL/THOMAS
AREA FORECAST DISCUSSION
NWS BUFFALO NY
425 AM EST MON FEB 11 2013
.SYNOPSIS...
AN AREA OF LOW PRESSURE WILL MOVE INTO SOUTHERN QUEBEC TODAY. THIS
WILL BRING A PERIOD OF RAIN EARLY TODAY...WITH SOME FREEZING
RAIN ACROSS THE INTERIOR VALLEYS AND A WINTRY MIX EAST OF LAKE
ONTARIO. AFTER THIS WINDS WILL INCREASE BEHIND AN ASSOCIATED COLD
FRONT...CAUSING RAIN SHOWERS TO CHANGE TO SNOW LATER TODAY AND
TONIGHT.
&&
.NEAR TERM /THROUGH TONIGHT/...
THERE WILL BE SEVERAL TRANSITIONS TODAY...AS A SERIES OF BOUNDARIES
ASSOCIATED WITH LOW PRESSURE ACROSS THE UPPER LAKES WILL INFLUENCE
OUR WEATHER.
THROUGH THIS MORNING...THE MAIN SOURCE OF LIFT WILL COME FROM AN
AREA OF WARM AIR ADVECTION ALOFT. RADAR TRENDS SUGGEST STEADIEST
RAINS WILL FOCUS NORTH OF A BUFFALO TO ROCHESTER LINE...WITH LIGHTER
QPFS ACROSS THE SOUTHERN TIER. FORTUNATELY...TEMPERATURES SHOULD
REMAIN JUST ABOVE FREEZING IN THESE LOCATIONS...WITH DOWNSLOPING
OFFSETTING EVAPORATIONAL COOLING. A FREEZING RAIN ADVISORY REMAINS
IN EFFECT ACROSS THE INTERIOR...WHERE TEMPERATURES AT 400 AM ARE IN
THE LOWER TO MID 30S. HOWEVER...WITH RAIN MOVING IN AND DEW POINTS
IN THE 20S...EXPECT TEMPERATURES TO DROP A FEW DEGREES AS RAIN
STARTS. RADAR TRENDS ARE WELL CAPTURED BY THE HRRR (THE NAM/GFS/RGEM
ARE TOO HIGH FOR QPF ACROSS THE INTERIOR). FOLLOWING THIS...EXPECT
SOME LIGHT (A FEW HUNDREDTHS OF AN INCH) QPF HOWEVER THIS WILL FALL
AS FREEZING RAIN IN MANY SPOTS...SO WILL KEEP THE ADVISORY UP.
STEADIER PRECIPITATION WILL MOVE EAST OF LAKE ONTARIO THROUGH
DAYBREAK...BRINGING THE GREATEST ICING POTENTIAL FOR THIS EVENT.
THERE WILL BE MODEST DOWNSLOPE WARMING HERE TOO...BUT WITH DRY AND
COOLER AIR IN PLACE EXPECT AROUND A TENTH OF AN INCH OF FREEZING
RAIN GLAZE...WITH PERHAPS SOME LIGHT SNOW OR SLEET ACCUMULATION. ALL
OF THIS PRECIPITATION SHOULD LIFT FROM SW-NE...ENDING ACROSS WESTERN
PORTIONS AROUND DAYBREAK...AND LATE THIS MORNING EAST OF LAKE
ONTARIO. THIS SHOULD PROVIDE A BRIEF LULL IN THE ACTION UNTIL THE
NEXT BOUNDARY CROSSES.
THE NEXT PHASE OF THIS EVENT WILL COME AS THE COLD FRONT ASSOCIATED
WITH THE LOW MOVES ACROSS THE REGION. IT WILL ENTER WESTERN NEW YORK
AROUND NOON...SWEEPING TO EAST OF LAKE ONTARIO AROUND SUNSET. THIS
WILL BRING MAINLY SCATTERED RAIN SHOWERS...BUT ITS MORE SIGNIFICANT
IMPACT WILL BE AN INCREASE IN WINDS BEHIND IT. GUSTY SOUTHWESTERLY
WINDS WILL PICK UP FIRST ACROSS THE NIAGARA FRONTIER...SPREADING TO
THE EAST LATE AFTERNOON AND EVENING. THE LOW IS NOT PARTICULARLY
DEEP...NOR IS THE COLD ADVECTION TOO STRONG. WITH ONLY MODEST
PRESSURE RISES DONT EXPECT EXTREMELY DEEP MIXING TO TAP THE 50 KNOTS
ALOFT...BUT STILL SUFFICIENT TO BRING ADVISORY CRITERIA GUSTS OF 45
TO 50 MPH LATER IN THE AFTERNOON. THE 230-240 DEGREE WIND DIRECTION
FAVORS THE STRONGER WINDS FROM THE LAKE ERIE SHORE ACROSS THE
NIAGARA FRONTIER TO ROCHESTER. LATER IN THE EVENING WINDS BECOME
MORE WESTERLY...WHICH WILL SPREAD STRONGER WINDS INTO THE INTERIOR
SOUTHERN TIER AND WESTERN FINGER LAKES. A WIND ADVISORY REMAINS IN
EFFECT ACROSS ALL BUT THE EASTERN LAKE ONTARIO REGION.
BEHIND THE COLD FRONT...THE UPPER LEVEL TROF ASSOCIATED WITH THE LOW
WILL MOVE ACROSS THE REGION. THIS WILL USHER IN COLDER AIR BOTH
ALOFT AND AT THE SURFACE. ITS IMPORTANT TO NOTE THAT THIS IS NOT A
VERY COLD AIR MASS...WITH 850 MB TEMPERATURES LIKELY TO DROP TO
AROUND -10C TONIGHT. THIS IS NOT REALLY COLD ENOUGH FOR PURE LAKE
EFFECT...BUT WITH SIGNIFICANT MOISTURE ASSOCIATED WITH THE UPPER
TROF...AND SOME UPSLOPE ENHANCEMENT...EXPECT THERE WILL BE SOME SNOW
EAST AND NORTHEAST OF THE LAKES TONIGHT. GIVEN THE MINIMAL
CONTRIBUTION FROM LAKE INSTABILITY...EXPECT QPFS ARE A BIT OVERDONE
BY THE NAM/RGEM WITH THE UPSLOPE...BUT DO FEEL SOME PRECIPITATION IS
CERTAINLY REASONABLE. SNOW RATIOS SHOULD NOT BE GREAT GIVEN THE
MARGINALLY COLD AIR...WITH 2 OR 3 INCHES SNOW ACCUMULATION LIKELY ON
THE TUG HILL TONIGHT...AND A BIT LESS ON THE CHAUTAUQUA RIDGE. IF
THERE WERE NOT ALREADY ADVISORIES IN PLACE...THIS PORTION OF THE
EVENT COULD REQUIRE A SNOW ADVISORY...BUT WITH A BREAK BETWEEN THE
TWO WILL HANDLE THIS AS TWO EVENTS RATHER THAN COMPLICATING THE
ISSUE. THIS IS A CHALLENGING EVENT...BECAUSE IF MODEL QPF DOES
VERIFY OR IF SNOW RATIONS EXCEED 20 TO 1...THEN THIS COULD ACTUALLY
APPROACH WARNING CRITERIA ON THE TUG HILL. AT THIS TIME...NEITHER OF
THESE SCENARIOS APPEAR LIKELY. SNOWS WILL BE LESS OFF LAKE ERIE...BUT
THE SW FLOW MAY BRING AN INCH OR SO ACROSS THE BUFFALO METRO
AREA...WITH LOCALLY HIGHER AMOUNTS ACROSS THE BOSTON HILLS AND
CHAUTAUQUA RIDGE.
OTHERWISE...TEMPERATURES WILL WARM BRIEFLY TODAY...ESPECIALLY IN THE
FINGER LAKES REGION...WITH HIGHS IN THE 40S AHEAD OF THE FRONT.
WINDS WILL BE GUSTY FOR A FEW HOURS THROUGH DAYBREAK ALONG I-90 FROM
THE NY/PA LINE TO BUFFALO AS DOWNSLOPING RESULTS IN GUSTS UP TO 40
MPH. 925 MB WINDS WILL DIMINISH AFTER 12Z...DIMINISHING WINDS HERE
UNTIL THE FRONT MOVES THROUGH.
&&
.SHORT TERM /TUESDAY THROUGH WEDNESDAY NIGHT/...
ON TUESDAY A SURFACE COLD FRONT WILL BE WELL TO THE EAST WITH COLD
AIR ADVECTING ACROSS THE EASTERN GREAT LAKES. THIS WILL BE A
MARGINAL SET UP FOR LAKE EFFECT SNOW...WITH THE MAIN FORCING
MECHANISM BEING MORE THE UPSLOPE FLOW OVER HIGHER TERRAIN EAST OF
BOTH GREAT LAKES.
TEMPERATURES AT 850 HPA WILL DROP TO AROUND -10C THROUGH THE DAY
TUESDAY WHICH CREATES VERY LITTLE INSTABILITY OFF LAKE ERIE...AND
ONLY MINOR LAKE INSTABILITY OFF LAKE ONTARIO. WHILE THERE WILL BE
PLENTY OF MOISTURE IN THE LOWER LEVELS...DRIER AIR BEHIND AN UPPER
LEVEL SHORTWAVE WILL LOWER THIS MOISTURE TO JUST BELOW THE SNOW
CRYSTAL GROWTH ZONE...AND WITH WEAK UPWARD OMEGA FORCING THERE WILL
NOT BE GOOD SNOW CRYSTAL GROWTH. WILL CONTINUE WITH LIKELY POPS
ACROSS THE HIGHER TERRAIN SOUTH OF BUFFALO...AND CATEGORICAL POPS
EAST OF LAKE ONTARIO WHERE LAKE ENHANCEMENT TO THE UPSLOPE SNOW
SHOWERS SHOULD BRING SEVERAL INCHES DURING THE DAY TUESDAY. ANOTHER
WEAK SHORTWAVE WILL CROSS WNY TUESDAY AND THIS WILL KEEP LOW CHANCE
POPS FOR A SNOW SHOWER EVEN ACROSS THE LOWER ELEVATIONS. THIS
SHORTWAVE WILL ALSO CAUSE LAKE ENHANCEMENT TO BE TRANSITORY THROUGH
THE DAY. A WINTER WEATHER ADVISORY MAY BE NEEDED FOR THIS SNOW EVENT
FOR THE TUG HILL REGION CONTINUING INTO TUESDAY...AND TUESDAY NIGHT.
HOWEVER WITH A CURRENT WINTER WEATHER ADVISORY ALREADY IN PLACE WILL
JUST MENTION THE PROSPECTS FOR ADVISORY LEVEL SNOWS IN THE HWO.
HIGHS ON TUESDAY WILL NOT CLIMB TOO MUCH FROM THEIR MORNING
LOWS...WITH TEMPERATURES THROUGH THE DAY LARGELY IN THE LOW TO MID
30S. WINDS WILL CONTINUE TO BE GUSTY THROUGH THE MORNING HOURS BUT
AS THE SURFACE LOW CARRIES FARTHER EASTWARD THROUGH ATLANTIC CANADA
AND WINDS ALOFT WEAKEN THE GUSTY SURFACE WINDS SHOULD DIMINISH
THROUGH THE DAY.
TUESDAY NIGHT SOME DRIER AIR BEGINS TO FILTER ACROSS THE GREAT
LAKES...YET THERE SHOULD STILL BE ENOUGH MOISTURE TO MAINTAIN THESE
SNOW SHOWERS...ESPECIALLY EAST OF LAKE ONTARIO. WITH THE FLOW VEERING
A LITTLE THE SNOW SHOWERS ACROSS THE EASTERN LAKE ONTARIO REGION
WILL BE MORE FOCUSED UPON OSWEGO AND SOUTHERN LEWIS COUNTIES.
WEDNESDAY FURTHER DRYING ALOFT AND WARM AIR ADVECTION WILL BRING AN
END TO THE WEAK LAKE ENHANCED SNOW SHOWERS EAST OF LAKE ONTARIO.
EXPECT JUST A CHANCE FOR MORNING LAKE EFFECT SNOW...CARRYING
NORTHWARD AND WEAKENING TO FLURRIES JUST SOUTH OF WATERTOWN. HIGH
PRESSURE WILL CROSS OUR REGION...CENTERED TO OUR SOUTH...AND WITH
THE AXIS OF A WEAK UPPER LEVEL RIDGE CROSSING THE EASTERN GREAT
LAKES WE SHOULD SEE ADDITIONAL SUNSHINE THROUGH THE DAY. CLOUDS WILL
BEGIN TO THICKEN FROM THE SOUTH WEDNESDAY AFTERNOON AND EVENING WELL
AHEAD OF A STORM SYSTEM CROSSING THE SOUTHEAST. A PRIMARY SURFACE
LOW WILL TRACK TO ABOUT WESTERN PENNSYLVANIA BEFORE AN UPPER LEVEL
SHORTWAVE TROUGH TRANSFERS ENERGY TO A DEVELOPING COASTAL LOW THAT
WILL QUICKLY DEEPEN. IT LOOKS LIKE THIS SYSTEM WILL MISS OUR
AREA...WITH JUST A SLIGHT CHANCE THAT SOME LIGHT SNOW WILL BRUSH BY
THE UPPER GENESEE RIVER VALLEY EARLY WEDNESDAY NIGHT. WITH THE WARM
AIR ADVECTION ALOFT AND WINDS FROM THE SOUTHEAST HIGHS WEDNESDAY
WILL CLIMB SEVERAL DEGREES WARMER THAN TUESDAY. HIGHS ON WEDNESDAY
WILL CLIMB INTO THE MID AND UPPER 30S WITH A SPOT 40 POSSIBLE.
&&
.LONG TERM /THURSDAY THROUGH SUNDAY/...
DURING THIS PERIOD...GFS/ECMWF FEATURE THE DEVELOPMENT OF A HIGH
AMPLITUDE RIDGE OVER THE WESTERN UNITED STATES AND A LARGE BROAD
TROUGH OVER THE EASTERN 2/3 OF THE U.S FROM THE COLORADO ROCKIES TO
THE EASTERN SEA BOARD. INITIALLY...TEMPERATURES WILL START OUT
SLIGHTLY ABOVE CLIMATOLOGY AND THEN ARE FORECAST TO GRADUALLY TREND
COLDER THROUGH THE WEEKEND SATURDAY TO SUNDAY.
A CLIPPER-TYPE LOW PRESSURE SYSTEM WILL SET THE STAGE...IT IS
FORECAST TO TRACK JUST TO THE WEST OF THE REGION ACROSS THE UPPER
GREAT LAKES. SOUTHERLY WINDS AHEAD OF THIS SYSTEM WILL PICK UP
ACROSS THE REGION..THEN A COLD FRONT WILL CROSS WESTERN AND NORTH
CENTRAL NEW YORK THURSDAY NIGHT INTO FRIDAY...BRINGING WITH IT A
CHANCE OF RAIN AND SNOW SHOWERS. COLDER AIR FOLLOWING THIS SYSTEM
WILL BRING A CHANCE FOR MORE SNOW SHOWERS AND POSSIBLE LAKE EFFECT
SNOW FRIDAY NIGHT AND SATURDAY. HOWEVER...THERE ARE DIFFERENCES
BETWEEN THE GFS/ECMWF WITH TIMING AND THE GENERAL STRENGTH OF THE
CLIPPER-TYPE SYSTEM FORECAST TO MOVE ACROSS THE REGION. AT THIS
POINT...IT SEEMS LIKELY THAT WESTERN/NORTH CENTRAL NY WILL SEE A
GRADUAL RETURN TO COLDER TEMPERATURES OVER THE PERIOD.
&&
.AVIATION /10Z MONDAY THROUGH FRIDAY/...
WHILE VFR CONDITIONS WILL BE IN PLACE FOR THE BULK OF THE REGION FOR
THE REST OF THE OVERNIGHT...AN AREA OF RAIN OVER LAKE ERIE AND
NORTHWEST PENNSYLVANIA WILL LIFT ACROSS OUR REGION DURING THE
OVERNIGHT HOURS. THIS PRECIPITATION SHOULD BE IN THE FORM OF RAIN AT
THE MAJOR TAF SITES ACROSS WESTERN NEW YORK (KBUF/KROC)...BUT THERE
IS A SLIGHT CHANCE THAT IT COULD FALL AS A BRIEF PERIOD OF -FZRA AT
KJHW. OTHERWISE...CIGS SHOULD DETERIORATE TO AT LEAST MVFR ACROSS
PARTS OF THE SRN TIER.
AS THE PCPN PUSHES FURTHER EAST BY DAYBREAK...A WINTRY MIX OF
FREEZING RAIN...SLEET AND EVEN SNOW WILL BE POSSIBLE AT KART.
ON MONDAY...THE PCPN WILL END FROM WEST TO EAST IN THE FORM OF JUST
RAIN...WITH AN ENDING TIME OF 12-14Z OVER THE WESTERN COUNTIES AND
16Z EAST OF LK ONTARIO. CIGS WILL LIKELY DROP TO MVFR FOR A FEW
HOURS IN THE WAKE OF THE STEADIER PCPN...WITH SOME IFR CIGS POSSIBLE
AT KJHW AND KELZ. THESE CIGS SHOULD GENERALLY IMPROVE DURING THEM
MIDDAY AND AFTERNOON.
BESIDES THE RISK OF MIXED WINTRY PRECIPITATION...THERE WILL BE SOME
LOW LEVEL WIND SHEAR TO CONTEND WITH TONIGHT AND FOR AT LEAST THE
MORNING HOURS OF MONDAY. WINDS AT 1500-2000 FT WILL AVERAGE 40-50
KTS WHILE SFC WINDS WILL BE IN THE VCNTY OF 10 KNOTS. BY MONDAY
AFTERNOON...THE STRONGER WINDS ALOFT SHOULD BE AT LEAST PARTIALLY
MIXING TO THE SFC. WIND GUSTS OVER 30KTS WILL BE POSSIBLE AT KIAG
AND KBUF LATER IN THE AFTERNOON.
ON MONDAY NIGHT...MVFR CONDITIONS WILL BE LIKELY WITH VSBYS BEING
LOWERED IN SNOW SHOWERS. THE MOST WIDESPREAD SNOWS WILL BE GENERATED
EAST OF BOTH LAKES WHERE IFR CONDITIONS WILL BE POSSIBLE.
OUTLOOK...
TUESDAY...MVFR/IFR IN LIGHT SNOW SHOWERS.
WEDNESDAY AND THURSDAY...MAINLY VFR.
FRIDAY...MVFR/IFR WITH A CHANCE OF SNOW.
&&
.MARINE...
SOUTHERLY WINDS WILL BE GUSTY THIS MORNING...ESPECIALLY ON LAKE
ERIE...AS STRONG WINDS ALOFT OCCASIONALLY MIX DOWN. AFTER
THIS...EXPECT A BIT OF LULL...BEFORE A COLD FRONT CROSSES THE WATERS
AROUND MIDDAY. THIS WILL SHIFT WINDS TO THE SOUTHWEST AND CAUSE AN
INCREASE TO 35 KNOT GALES BEHIND THE FRONT. EXPECT GALES TO CONTINUE
THROUGH TONIGHT...GRADUALLY SUBSIDING FROM WEST TO EAST ON TUESDAY.
HIGH PRESSURE WILL BUILD ACROSS THE REGION WEDNESDAY...WITH NO
HEADLINES ANTICIPATED.
&&
.BUF WATCHES/WARNINGS/ADVISORIES...
NY...FREEZING RAIN ADVISORY UNTIL 8 AM EST THIS MORNING FOR NYZ004-
005-012>014-019>021-085.
WIND ADVISORY FROM 1 PM THIS AFTERNOON TO 5 AM EST TUESDAY FOR
NYZ001>003-010>012-019-085.
WINTER WEATHER ADVISORY UNTIL NOON EST TODAY FOR NYZ007-008.
FREEZING RAIN ADVISORY UNTIL 10 AM EST THIS MORNING FOR NYZ006.
WIND ADVISORY FROM 6 PM THIS EVENING TO 5 AM EST TUESDAY FOR
NYZ004-013-014-020-021.
MARINE...SMALL CRAFT ADVISORY UNTIL 1 PM EST THIS AFTERNOON FOR LEZ040-
041.
GALE WARNING FROM 1 PM THIS AFTERNOON TO 4 AM EST TUESDAY
FOR LEZ020-040-041.
GALE WARNING FROM 1 PM THIS AFTERNOON TO 10 AM EST
TUESDAY FOR LOZ042-043-062-063.
SMALL CRAFT ADVISORY UNTIL 4 PM EST THIS AFTERNOON FOR
LOZ045.
GALE WARNING FROM 4 PM THIS AFTERNOON TO 1 PM EST TUESDAY
FOR LOZ044-045-064-065.
&&
$$
SYNOPSIS...APFFEL
NEAR TERM...APFFEL
SHORT TERM...THOMAS
LONG TERM...AR
AVIATION...RSH
MARINE...APFFEL/THOMAS
AREA FORECAST DISCUSSION
NWS RALEIGH NC
310 PM EST MON FEB 11 2013
.SYNOPSIS...
A COLD FRONT WILL CROSS THE REGION THIS EVENING BEFORE SETTLING JUST
TO OUR SOUTH LATE TONIGHT. WEAK HIGH PRESSURE WILL MOVE IN LATE
TONIGHT THROUGH TUESDAY. A LOW PRESSURE SYSTEM WILL TRACK ALONG THE
FRONT TUESDAY NIGHT AND WEDNESDAY... BRINGING UNSETTLED WEATHER.
&&
.NEAR TERM /THROUGH TUESDAY NIGHT/...
AS OF 245 PM MONDAY...
THROUGH TONIGHT: AS EXPECTED... THE WEDGE AIR MASS OVER THE TRIAD
REGION HAS BEEN VERY TOUGH TO DISLODGE... AS EARLY AFTERNOON TEMPS
REMAIN IN THE LOWER 50S WITH FOG AND VERY LOW STRATUS HOLDING ON...
WHILE READINGS ARE MOSTLY IN THE 60S ELSEWHERE. SW WINDS JUST OFF
THE SURFACE (AT 1-2 KFT AGL) ARE NOT QUITE AS STRONG AS THEY WERE
THIS MORNING WITH THE DEPARTURE OF THE LOW LEVEL JET TO THE EAST BUT
THEY CONTINUE TO PULL IN ENOUGH WARM AIR ALOFT SUCH THAT THE
SURFACE-BASED STABLE LAYER IS REINFORCED VIA DIFFERENTIAL TEMP
ADVECTION IN THE VERTICAL... DESPITE THE LACK OF A FEED OF COOL AIR
AT THE SURFACE. AS SUCH... WE MAY SEE A MUTED FORM OF THIS WEDGE AIR
MASS HANG IN OVER THE TRIAD THROUGH THIS EVENING... UNTIL THE COLD
FRONT FINALLY SWEEPS THROUGH. LATEST CONVECTION-ALLOWING MODEL RUNS
INCLUDING THE HRRR AND HIGH-RES WRF-NMM AND WRF-ARW SHOW WEAK LOW
PRESSURE OVER NRN GA TRACKING ALONG THE FRONT AND IS ASSOCIATED WITH
THE UPSTREAM PRECIP BAND NOW ACROSS NRN GA AND UPSTATE SC STREAMING
TO THE ENE ACROSS THE FAR SRN/SE CWA... HOWEVER PREFRONTAL
CONVECTION TO THE SSE OVER SRN GA MAY INTERRUPT THE POLEWARD
MOISTURE TRANSPORT SUCH THAT WE`LL ONLY SEE LIGHT AMOUNTS AT MOST.
WILL HOLD ONTO THE LOW CHANCE POPS OVER THE FAR SRN AND SE CWA
THROUGH THIS EVENING... WITH DRY WEATHER OVERNIGHT. A SUBTLE MID
LEVEL WAVE CONNECTED TO THE VORTEX CROSSING FAR SE ONTARIO AND SRN
QUEBEC WILL CROSS THE MIDATLANTIC REGION LATER TONIGHT... FLATTENING
THE MID LEVEL FLOW AND PROPELLING THE SURFACE FRONT TO OUR
SOUTHEAST. THIS FLOW WILL REMAIN QUITE SWIFT TONIGHT... 80-90 KTS AT
500 MB... WITH PLENTY OF MOISTURE AT 310K-320K... SO EXPECT ABUNDANT
MID LEVEL CLOUDS TO STREAM ACROSS THE AREA THROUGH THE NIGHT. LOWS
39-47.
FOR TUESDAY/TUESDAY NIGHT: WILL SEE A BRIEF RESPITE IN THE ACTIVE
PATTERN ON TUESDAY BEFORE THE RAIN RAMPS BACK UP TUESDAY EVENING.
THE FRONT WILL HOLD TO OUR SOUTH WITH WEAK HIGH PRESSURE BUILDING
OVER THE REGION. MID LEVEL FLOW REMAINS FAST (NEAR 80 KTS) OVER THE
REGION BUT WILL BECOME GENTLY ANTICYCLONIC FOR A TIME... AS THE DEEP
TROUGH LOCATED OVER THE FOUR CORNERS REGION STARTS TO KICK EASTWARD
INTO THE SRN PLAINS. WE`LL LIKELY SEE PARTLY SUNNY SKIES GIVE WAY TO
GREATER SUNSHINE TOWARD AFTERNOON... PARTICULARLY ACROSS THE
NORTHERN CWA. LOW LEVEL THICKNESSES AS WELL AS THE LOW LEVEL THERMAL
STRUCTURE SUPPORT HIGHS IN THE UPPER 50S TO LOWER 60S. THE MID LEVEL
TROUGH SHIFTS THROUGH THE MID MISS VALLEY AS A POSITIVELY-TILTED
WEAKENING WAVE... AND MODELS ALL AGREE ON A RAPID INCREASE IN DEEP
MOIST ISENTROPIC UPGLIDE FROM 285K-305K OUT AHEAD OVER THE
CAROLINAS. SIMILAR TO LAST NIGHT`S RAINFALL PATTERN... WITH THE
FRONT LIKELY TO STILL HOLD SOUTH OF THE NC BORDER THROUGH TUESDAY
NIGHT AND WITH INCREASING LAPSE RATES AND INSTABILITY OVER
MS/AL/GA... WE SHOULD SEE THE GREATEST RISK OF HEAVY PRECIP CONFINED
TO ALONG AND SOUTH OF THE BORDER. WITH A GOOD CHANCE OF A CONVECTIVE
BAND WELL TO OUR SOUTH AND SW TUESDAY NIGHT... MOISTURE TRANSPORT
MAY BE SUFFICIENTLY REDUCED TO GREATLY LIMIT AMOUNTS AND COVERAGE
OVER NRN NC. NEVERTHELESS... GIVEN THE RESURGENCE OF 1+ INCH PRECIP
WATER INTO THE SRN AND ERN CWA OVERNIGHT... CONFIDENCE IS HIGH
ENOUGH FOR CATEGORICAL POPS IN THE SRN/SE CWA... TRENDING TO GOOD
CHANCE NEAR THE VA BORDER. AMOUNTS ALONG/NORTH OF HIGHWAY 64 MAY BE
LESS THAN A TENTH... WHILE AREAS NEAR THE SC BORDER COULD SEE A HALF
INCH OR MORE. LOWS 40-46. -GIH
&&
.SHORT TERM /WEDNESDAY THROUGH THURSDAY NIGHT/...
AS OF 310 PM MONDAY...
SHORTWAVE EJECTING OUT OF THE FOUR CORNERS REGION TUESDAY WILL RACE
EAST ACROSS THE MS AND TN VALLEY REGIONS BY TUESDAY NIGHT
NIGHT...SHEARING OUT AS IT CROSSES THE CAROLINAS ON WEDNESDAY. AS
PRECIP SPREADS INTO THE AREA ON THE HEELS OF WEAK HIGH PRESSURE LATE
TUESDAY NIGHT...ANOTHER CAD AIRMASS SHOULD DEVELOP OVER THE PIEDMONT.
MODELS CONTINUE TO DIFFER REGARDING THE TRACK OF THE ASSOCIATED
SURFACE LOW ALONG A STALLED OUT FRONTAL ZONE DRAPED ACROSS THE
GULF/SOUTHEAST COAST. THE NAM CONTINUES TO BE THE NORTHERN OUTLIER
WITH A LOW TRACK WEST OF THE MOUNTAINS. THE ECMWF APPEARS MORE
REALISTIC WITH A TRACK ACROSS GA/SC TOWARD THE NC COAST. THE GFS
SOMEWHERE IN BETWEEN TRACKING THE LOW TOWARD THE PIEDMONT...THEN
JUMPING ACROSS THE EXPECTED CAD AIRMASS TO THE VA COAST. FAVORING A
SOUTHERN TRACK OF THE LOW...THE BEST FOCUS OF DEEP MOISTURE AND LOW
LEVEL CONVERGENCE WILL BE ACROSS SC TO SOUTHEAST NC...WHERE MODELS
GIVE ONE HALF TO NEAR ONE INCH OF QPF IN TOTAL. AHEAD OF THE
SHORTWAVE...MODELS SUGGEST A PLUME A STEEP MID LEVEL LAPSE RATES IN
EXCESS OF -6.5 C/KM WITH A TRAJECTORY ACROSS CENTRAL NC. MODEST
UPPER LEVEL FORCING FROM THE VORT MAX/LEFT EXIT REGION OF THE
STJ...COMBINED WITH STRENGTHENING ISENTROPIC ACCENT IN THE LOW
LEVELS...COULD LEAD TO A CHANCE OF THUNDER WEDNESDAY AFTERNOON.
POPS WILL BE INCREASED TO ABOVE 80 PERCENT WITH THE HIGHEST VALUES
SOUTH WEDNESDAY MORNING. HIGHS IN THE 40S TO POSSIBLY LOWER 50S IN
THE SOUTHEAST.
WESTERLY FLOW AND COLD/DRY ADVECTION IN THE WAKE OF THE DEPARTING
SYSTEM SHOULD HELP TO SCOUR SOME OF THE LINGERING LOW CLOUDS
WEDNESDAY NIGHT. LOWS IN THE LOW TO MID 30S.
TEMPS SHOULD CLIMB BACK TO AROUND NORMAL ON THURSDAY WITH A
LIGHT SOUTHWESTERLY WIND DEVELOPING AS HEIGHTS SLOWLY BEGIN TO FALL
OVER THE CENTRAL US. HIGHS 52-57. LOWS THURSDAY NIGHT IN THE LOW
TO MID 30S
&&
.LONG TERM /FRIDAY THROUGH MONDAY/...
AS OF 310 PM MONDAY...
MEDIUM RANGE MODELS ARE IN GOOD AGREEMENT ON THE LONGWAVE PATTERN
THROUGH THE WEEKEND...WITH RIDGING OVER THE WESTERN US AND A DEEP
TROUGH DEVELOPING OVER THE EASTERN US. DETAILS REGARDING THE
STRENGTH AND TIMING SHORTWAVES ROTATING INTO THE EAST COAST TROUGH
REMAIN SOMEWHAT UNCERTAIN...BUT MODELS CURRENTLY PROJECT A WEAKER
TROUGH AND COLD FRONTAL PASSAGE FRIDAY... AND A MORE SUBSTANTIAL
TROUGH ARRIVING SATURDAY/SATURDAY NIGHT. BASED ON THE ECMWF AND A
CONSENSUS OF GEFS SOLUTIONS...HPC CONTINUES TO FAVOR CYCLOGENESIS
OFF THE MID-ATLANTIC COAST SATURDAY NIGHT...SUPPORTING LESS IMPACT
OVER THE CAROLINAS. HOWEVER...EVEN WITH RUN-TO-RUN INCONSISTENCIES
IN THE GFS/ECMWF...MODELS SUGGEST THE UPPER TROUGH MAY BE STRONG
ENOUGH TO OVERCOME THE RELATIVELY DRY AIR OVER CENTRAL NC AND
PRODUCE SOME LIGHT QPF. FORECAST LOW LEVEL THICKNESSES PLUMMET
WELL BELOW 1300M WITH THE SECOND TROUGH ON SATURDAY....SO CONFIDENCE
IS MODERATELY HIGH IN THERMAL PROFILES WILL BECOME FAVORABLE FOR
SNOW SHOWERS. THE MAIN QUESTION WILL BE MOISTURE AVAILABILITY OR
GENERATION FROM THE TROUGH....BUT THERE HAS BEEN ENOUGH CONSISTENCY
IN THE MODELS TO INTRODUCE A SLIGHT CHANCE OF RAIN OR SNOW SHOWERS
INTO THE FORECAST SATURDAY EVENING/NIGHT. TEMPS WILL BE TWO TO
THREE CATEGORIES BELOW NORMAL SATURDAY AND ESPECIALLY SUNDAY.
BEYOND SUNDAY...MODELS SHOW A RIDGE BUILDING EASTWARD ACROSS THE
CENTRAL PORTION OF THE COUNTRY EARLY NEXT WEEK WITH A MODERATING
TREND AND DRY CONDITIONS.
&&
.AVIATION /18Z MONDAY THROUGH SATURDAY/...
AS OF 120 PM TUESDAY...
LIFR CONDITIONS WILL PERSIST FOR ANOTHER FEW HOURS AT INT/GSO...
WHILE IFR/MVFR CIGS WITH VFR VSBYS WILL HOLD ELSEWHERE. A WEDGE
BOUNDARY REMAINS TO THE SE OF INT/GSO... AND THE LIFR CIGS AND VSBYS
AROUND 1 SM HAVE BUDGED LITTLE SO FAR TODAY. EXPECT CIGS TO SLOWLY
LIFT EVERYWHERE BUT IMPROVE TO NO BETTER THAN MVFR THROUGH 23Z. CIGS
ARE EXPECTED TO RISE TO VFR 01Z-04Z AS A COLD FRONT MOVES EAST
THROUGH THE AREA... AND SWRLY SURFACE WINDS SHIFT AROUND TO WSW THEN
FROM THE WEST AS A COLD FRONT MOVES THROUGH THE AREA... BEFORE
SETTLING JUST TO OUR SOUTH OVERNIGHT. WINDS WILL APPROACH LLWS
CRITERIA THROUGH THIS AFTERNOON AS SPEEDS AT 2 THOUSAND FT AGL WILL
REMAIN FROM THE SW AT 35-40 KTS... BUT THE EXIT OF THE LOW LEVEL JET
WILL CAUSE WINDS ALOFT TO DECREASE TO 25-35 KTS BY 00Z. THE
INCREASING WINDS WITH HEIGHT MAY STILL CAUSE ISSUES WITH MECHANICAL
TURBULENCE THROUGH THIS EVENING HOWEVER. VFR CIGS WILL HOLD FROM
AROUND MIDNIGHT THROUGH TUESDAY MORNING AS WEAK HIGH PRESSURE BUILDS
IN.
LOOKING BEYOND 18Z TUESDAY... VFR CIGS WILL HOLD INTO TUESDAY
EVENING BUT THEN DROP BACK DOWN TO IFR/LIFR OVERNIGHT AS A WAVE OF
LOW PRESSURE TRACKS ALONG THE FRONT STALLED JUST TO OUR SOUTH. THESE
POOR AVIATION CONDITIONS SHOULD HOLD THROUGH WEDNESDAY BEFORE
IMPROVING TO VFR WEDNESDAY EVENING AS THE LOW EXITS. VFR CONDITIONS
WILL THEN HOLD UNTIL SATURDAY... WHEN WE COULD SEE ANOTHER STORM
SYSTEM BRINGING SUB-VFR CONDITIONS. -GIH
&&
.RAH WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...HARTFIELD
NEAR TERM...HARTFIELD
SHORT TERM...SMITH
LONG TERM...SMITH
AVIATION...HARTFIELD
AREA FORECAST DISCUSSION
NWS RALEIGH NC
245 PM EST MON FEB 11 2013
.SYNOPSIS...
A COLD FRONT WILL CROSS THE REGION THIS EVENING BEFORE SETTLING JUST
TO OUR SOUTH LATE TONIGHT. WEAK HIGH PRESSURE WILL MOVE IN LATE
TONIGHT THROUGH TUESDAY. A LOW PRESSURE SYSTEM WILL TRACK ALONG THE
FRONT TUESDAY NIGHT AND WEDNESDAY... BRINGING UNSETTLED WEATHER.
&&
.NEAR TERM /THROUGH TUESDAY NIGHT/...
AS OF 245 PM MONDAY...
THROUGH TONIGHT: AS EXPECTED... THE WEDGE AIR MASS OVER THE TRIAD
REGION HAS BEEN VERY TOUGH TO DISLODGE... AS EARLY AFTERNOON TEMPS
REMAIN IN THE LOWER 50S WITH FOG AND VERY LOW STRATUS HOLDING ON...
WHILE READINGS ARE MOSTLY IN THE 60S ELSEWHERE. SW WINDS JUST OFF
THE SURFACE (AT 1-2 KFT AGL) ARE NOT QUITE AS STRONG AS THEY WERE
THIS MORNING WITH THE DEPARTURE OF THE LOW LEVEL JET TO THE EAST BUT
THEY CONTINUE TO PULL IN ENOUGH WARM AIR ALOFT SUCH THAT THE
SURFACE-BASED STABLE LAYER IS REINFORCED VIA DIFFERENTIAL TEMP
ADVECTION IN THE VERTICAL... DESPITE THE LACK OF A FEED OF COOL AIR
AT THE SURFACE. AS SUCH... WE MAY SEE A MUTED FORM OF THIS WEDGE AIR
MASS HANG IN OVER THE TRIAD THROUGH THIS EVENING... UNTIL THE COLD
FRONT FINALLY SWEEPS THROUGH. LATEST CONVECTION-ALLOWING MODEL RUNS
INCLUDING THE HRRR AND HIGH-RES WRF-NMM AND WRF-ARW SHOW WEAK LOW
PRESSURE OVER NRN GA TRACKING ALONG THE FRONT AND IS ASSOCIATED WITH
THE UPSTREAM PRECIP BAND NOW ACROSS NRN GA AND UPSTATE SC STREAMING
TO THE ENE ACROSS THE FAR SRN/SE CWA... HOWEVER PREFRONTAL
CONVECTION TO THE SSE OVER SRN GA MAY INTERRUPT THE POLEWARD
MOISTURE TRANSPORT SUCH THAT WE`LL ONLY SEE LIGHT AMOUNTS AT MOST.
WILL HOLD ONTO THE LOW CHANCE POPS OVER THE FAR SRN AND SE CWA
THROUGH THIS EVENING... WITH DRY WEATHER OVERNIGHT. A SUBTLE MID
LEVEL WAVE CONNECTED TO THE VORTEX CROSSING FAR SE ONTARIO AND SRN
QUEBEC WILL CROSS THE MIDATLANTIC REGION LATER TONIGHT... FLATTENING
THE MID LEVEL FLOW AND PROPELLING THE SURFACE FRONT TO OUR
SOUTHEAST. THIS FLOW WILL REMAIN QUITE SWIFT TONIGHT... 80-90 KTS AT
500 MB... WITH PLENTY OF MOISTURE AT 310K-320K... SO EXPECT ABUNDANT
MID LEVEL CLOUDS TO STREAM ACROSS THE AREA THROUGH THE NIGHT. LOWS
39-47.
FOR TUESDAY/TUESDAY NIGHT: WILL SEE A BRIEF RESPITE IN THE ACTIVE
PATTERN ON TUESDAY BEFORE THE RAIN RAMPS BACK UP TUESDAY EVENING.
THE FRONT WILL HOLD TO OUR SOUTH WITH WEAK HIGH PRESSURE BUILDING
OVER THE REGION. MID LEVEL FLOW REMAINS FAST (NEAR 80 KTS) OVER THE
REGION BUT WILL BECOME GENTLY ANTICYCLONIC FOR A TIME... AS THE DEEP
TROUGH LOCATED OVER THE FOUR CORNERS REGION STARTS TO KICK EASTWARD
INTO THE SRN PLAINS. WE`LL LIKELY SEE PARTLY SUNNY SKIES GIVE WAY TO
GREATER SUNSHINE TOWARD AFTERNOON... PARTICULARLY ACROSS THE
NORTHERN CWA. LOW LEVEL THICKNESSES AS WELL AS THE LOW LEVEL THERMAL
STRUCTURE SUPPORT HIGHS IN THE UPPER 50S TO LOWER 60S. THE MID LEVEL
TROUGH SHIFTS THROUGH THE MID MISS VALLEY AS A POSITIVELY-TILTED
WEAKENING WAVE... AND MODELS ALL AGREE ON A RAPID INCREASE IN DEEP
MOIST ISENTROPIC UPGLIDE FROM 285K-305K OUT AHEAD OVER THE
CAROLINAS. SIMILAR TO LAST NIGHT`S RAINFALL PATTERN... WITH THE
FRONT LIKELY TO STILL HOLD SOUTH OF THE NC BORDER THROUGH TUESDAY
NIGHT AND WITH INCREASING LAPSE RATES AND INSTABILITY OVER
MS/AL/GA... WE SHOULD SEE THE GREATEST RISK OF HEAVY PRECIP CONFINED
TO ALONG AND SOUTH OF THE BORDER. WITH A GOOD CHANCE OF A CONVECTIVE
BAND WELL TO OUR SOUTH AND SW TUESDAY NIGHT... MOISTURE TRANSPORT
MAY BE SUFFICIENTLY REDUCED TO GREATLY LIMIT AMOUNTS AND COVERAGE
OVER NRN NC. NEVERTHELESS... GIVEN THE RESURGENCE OF 1+ INCH PRECIP
WATER INTO THE SRN AND ERN CWA OVERNIGHT... CONFIDENCE IS HIGH
ENOUGH FOR CATEGORICAL POPS IN THE SRN/SE CWA... TRENDING TO GOOD
CHANCE NEAR THE VA BORDER. AMOUNTS ALONG/NORTH OF HIGHWAY 64 MAY BE
LESS THAN A TENTH... WHILE AREAS NEAR THE SC BORDER COULD SEE A HALF
INCH OR MORE. LOWS 40-46. -GIH
&&
.SHORT TERM /WEDNESDAY THROUGH WEDNESDAY NIGHT/...
AS OF 305 AM MONDAY...
WEDNESDAY...EXPECT WIDESPREAD RAIN TO OVERSPREAD CENTRAL NC EARLY
WED AND CONTINUE WELL INTO THE AFTERNOON. THE PRECIP AND OVERCAST
SKIES WILL RESULT IN BELOW NORMAL TEMPS WITH MAX TEMPS HOLDING INT
EH 40S ACROSS MOST OF THE PIEDMONT...AND THE LOWER 50S IN THE FAR
SOUTH-SE.
WEDNESDAY NIGHT...S/W CROSSES THE REGION IN THE EVENING THEN EXITS
THE COAST. DRIER WNW FLOW BEHIND THIS SYSTEM AS WELL AS SUBSIDENCE
WILL AID TO DISSIPATE CLOUD COVERAGE NW-SE DURING THE OVERNIGHT
HOURS. RESIDUAL MOISTURE MAY RESULT IN SOME AREAS OF FOG BUT
CONFIDENCE NOT HIGH ENOUGH AT THIS TIME TO INTRODUCE IN THE FORECAST
AS MAY BE ENOUGH MIXING TO PREVENT FOG FROM DEVELOPING. MIN TEMPS
MID-UPPER 30S.
&&
.LONG TERM /THURSDAY THROUGH SUNDAY/...
AS OF 305 AM MONDAY...
THURSDAY INTO FRIDAY...RELATIVELY TRANQUIL WEATHER PATTERN
ANTICIPATED AS BROAD TROUGH OVER THE EASTERN U.S. WILL CAUSE A WLY
FLOW THROUGH THE COLUMN OVER CENTRAL NC. THIS USUALLY YIELDS DRY
WEATHER WITH MILD TEMPS. LOW LEVEL THICKNESSES A SHADE ABOVE NORMAL
THU AND NEAR NORMAL FRI BUT WLY FLOW USUALLY ADDS ADDITIONAL
WARMING. AFTERNOON TEMPS IN THE 50S BOTH DAYS...APPROACHING 60 N THE
FAR SOUTH FRI.
BROAD UPPER TROUGH OVER EASTERN U.S. WILL UNDERGO AMPLIFICATION
SATURDAY INTO SUNDAY AS PACIFIC ENERGY IS SHUNTED WELL NWD INTO
ALASKA AND BRITISH COLUMBIA IN RESPONSE TO A STOUT UPPER LEVEL RIDGE
OVER THE WESTERN U.S. THIS ENERGY DIVES ON SEWD INTO THE NORTH
CENTRAL U.S. INITIATING THE AMPLIFICATION OF THE TROUGH. THIS WILL
CAUSE A MODIFIED ARCTIC AIR MASS TO SPREAD SEWD ACROSS MUCH OF THE
EASTERN U.S. THIS WEEKEND. THE LEADING EDGE OF THIS COLDER AIR WILL
SPREAD ACROSS CENTRAL NC FRI NIGHT INTO SATURDAY.
MODEL GUIDANCE CONTINUES TO EXHIBIT POSSIBLE SURFACE CYCLOGENESIS
ASSOCIATED WITH THIS AMPLIFICATION OFF THE EASTERN SEABOARD IN
VICINITY OF THE MID ATLANTIC COAST NWD TO NEW ENGLAND. CONSIDERING
THE STRENGTH OF THE DISTURBANCES ALOFT...MAY BE ENOUGH TO TRIGGER
SCATTERED SHOWERS ACROSS CENTRAL NC SATURDAY INTO SATURDAY EVENING.
PARTIAL THICKNESSES AND FORECAST GFS BUFKIT SOUNDINGS SUGGEST THAT
SNOW SHOWERS WOULD BE FAVORED OVER RAIN SHOWERS BUT MODELS MAY BE
COOLING OFF THE COLUMN TOO QUICKLY. SINCE WE ARE TALKING ABOUT DAY
6...PREFER TO MAINTAIN A SLIGHT CHANCE POP FOR NOW AND KEEP PRECIP
ALL LIQUID. HOWEVER DID BUMP UP CLOUDINESS A TAD AND LOWERED MAX
TEMPS SATURDAY 2-3 DEGREES FROM THE PREVIOUS FORECAST. MAX TEMPS
SATURDAY IN THE 40S TO NEAR 50 SOUTHEAST. IF PRECIP MORE EXTENSIVE
THAN CURRENT THINKING...MAX TEMPS COULD BE TOO WARM BY AS MUCH AS
5-6 DEGREES. BULK OF COLDER AIR WILL SETTLE OVER THE REGION SUNDAY
WITH MAX TEMPS 10-14 DEGREES BELOW NORMAL. MIN TEMPS SUN MORNING IN
THE 20S.
&&
.AVIATION /18Z MONDAY THROUGH SATURDAY/...
AS OF 120 PM TUESDAY...
LIFR CONDITIONS WILL PERSIST FOR ANOTHER FEW HOURS AT INT/GSO...
WHILE IFR/MVFR CIGS WITH VFR VSBYS WILL HOLD ELSEWHERE. A WEDGE
BOUNDARY REMAINS TO THE SE OF INT/GSO... AND THE LIFR CIGS AND VSBYS
AROUND 1 SM HAVE BUDGED LITTLE SO FAR TODAY. EXPECT CIGS TO SLOWLY
LIFT EVERYWHERE BUT IMPROVE TO NO BETTER THAN MVFR THROUGH 23Z. CIGS
ARE EXPECTED TO RISE TO VFR 01Z-04Z AS A COLD FRONT MOVES EAST
THROUGH THE AREA... AND SWRLY SURFACE WINDS SHIFT AROUND TO WSW THEN
FROM THE WEST AS A COLD FRONT MOVES THROUGH THE AREA... BEFORE
SETTLING JUST TO OUR SOUTH OVERNIGHT. WINDS WILL APPROACH LLWS
CRITERIA THROUGH THIS AFTERNOON AS SPEEDS AT 2 THOUSAND FT AGL WILL
REMAIN FROM THE SW AT 35-40 KTS... BUT THE EXIT OF THE LOW LEVEL JET
WILL CAUSE WINDS ALOFT TO DECREASE TO 25-35 KTS BY 00Z. THE
INCREASING WINDS WITH HEIGHT MAY STILL CAUSE ISSUES WITH MECHANICAL
TURBULENCE THROUGH THIS EVENING HOWEVER. VFR CIGS WILL HOLD FROM
AROUND MIDNIGHT THROUGH TUESDAY MORNING AS WEAK HIGH PRESSURE BUILDS
IN.
LOOKING BEYOND 18Z TUESDAY... VFR CIGS WILL HOLD INTO TUESDAY
EVENING BUT THEN DROP BACK DOWN TO IFR/LIFR OVERNIGHT AS A WAVE OF
LOW PRESSURE TRACKS ALONG THE FRONT STALLED JUST TO OUR SOUTH. THESE
POOR AVIATION CONDITIONS SHOULD HOLD THROUGH WEDNESDAY BEFORE
IMPROVING TO VFR WEDNESDAY EVENING AS THE LOW EXITS. VFR CONDITIONS
WILL THEN HOLD UNTIL SATURDAY... WHEN WE COULD SEE ANOTHER STORM
SYSTEM BRINGING SUB-VFR CONDITIONS. -GIH
&&
.RAH WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...HARTFIELD
NEAR TERM...HARTFIELD
SHORT TERM...WSS
LONG TERM...WSS
AVIATION...HARTFIELD
AREA FORECAST DISCUSSION
NWS RALEIGH NC
125 PM EST MON FEB 11 2013
.SYNOPSIS...
A WARM FRONT WILL CONTINUE MOVING NORTHWARD THROUGH THE AREA TODAY.
A COLD FRONT WILL CROSS THE REGION THIS EVENING BEFORE SETTLING JUST
TO OUR SOUTH... THEN WEAK HIGH PRESSURE WILL MOVE IN LATE TONIGHT
THROUGH TUESDAY. A LOW PRESSURE SYSTEM WILL TRACK ALONG THE FRONT
AND AFFECT THE AREA ON WEDNESDAY.
&&
.NEAR TERM /THROUGH TUESDAY/...
AS OF 950 AM MONDAY...
REST OF TODAY: MAIN CONCERNS THIS MORNING ARE DEALING WITH THE
DEPARTING RAIN... WIDELY VARYING TEMPS... AND WIND. WEDGE REGIME
REMAINS WELL-ENTRENCHED OVER THE FAR NRN AND NW PIEDMONT...
BISECTING THE TRIAD REGION WITH 9 AM TEMPS IN THE UPPER 50S IN
ASHEBORO WHILE LOWER 40S HOLD AT LEXINGTON WITH FOG/STRATUS AND VERY
LIGHT TO CALM AIR. THE 12Z GSO SOUNDING SHOWS A FORMIDABLE STABLE
LAYER (+4C DIFFERENTIAL FROM SURFACE TO WARM NOSE ALOFT) WITH DEEP
SATURATION... AND EVEN OUTSIDE OF THIS DEFINED WEDGE... DESPITE THE
MILDER TEMPS IN THE 50S... THE LOW LEVELS (UNDER 900 MB) REMAIN
NEUTRAL TO SLIGHTLY STABLE AS NOTED BY RECENT AMDAR AIRCRAFT
SOUNDINGS NEAR RDU. WINDS HERE ARE BEGINNING TO PICK UP OUT OF THE
SOUTH AND SW THOUGH... INDICATING THAT IMPROVED LOW LEVEL MIXING IS
IMMINENT. THE WIDESPREAD LIGHT RAIN IS ON ITS WAY OUT A BIT MORE
QUICKLY THAN EARLIER ANTICIPATED... HOWEVER WITH BLENDED TPW IMAGERY
SHOWING PRECIP WATER VALUES OVER 200 PERCENT OF NORMAL ACROSS THE
ENTIRE REGION... THE RISK OF PATCHY SHOWERS WILL REMAIN FOR ANOTHER
SEVERAL HOURS AS THE MOIST COLUMN WILL STAY VULNERABLE TO EVEN
SUBTLE FORCING FOR ASCENT. WILL HOLD ONTO SMALL POPS MAINLY S/E OF
THE TRIAD INTO THE AFTERNOON. LOW CLOUDS SHOULD HOLD IN EVERYWHERE
UNTIL MID AFTERNOON WITH THE CONTINUED LOW-MID LEVEL FLOW FROM THE
SW ELIMINATING THE POTENTIAL FOR SIGNIFICANT DOWNSLOPE DRYING UNTIL
LATE... WHEN THE MID LEVEL PERTURBATION NOW OVER NW NC MOVES OFF THE
COAST. TEMPS ARE ALWAYS TOUGH TO GAUGE IN THESE WEDGE SITUATIONS
ESPECIALLY WHEN THERE IS NO LONGER A FEED OF LOW LEVEL DRY AIR TO
MAINTAIN THE STABLE POOL. ALL FINE-RESULTION GUIDANCE INCLUDING THE
LOCAL WRF AND HRRR FAVORS A MIXING-OUT OF THE REMAINING WEDGE OVER
OUR NW CWA BY EARLY AFTERNOON... ALTHOUGH THE ABUNDANT THICK CLOUDS
FOR MUCH OF THE DAY WILL CUT DOWN ON WARMING ALL ACROSS THE AREA.
NEVERTHELESS.... ANOMALOUSLY WARM THICKNESSES WILL RISE FURTHER THIS
AFTERNOON... AND STILL EXPECT HIGHS IN THE MID 60S TO NEAR 70 OVER
MUCH OF THE CWA EXCEPT FOR NEAR 60 IN THE NW CORNER. SINCE WE WON`T
FULLY MIX UP BEYOND 900 MB UNTIL LATE IN THE DAY... WHEN THE 50-60
KT LOW LEVEL JET WILL HAVE EXITED... OUR WIND GUSTS WILL REMAIN WELL
BELOW ADVISORY THRESHOLD... YET WE SHOULD STILL SEE GUSTS BECOME
MORE FREQUENT AND HIGHER THIS AFTERNOON ESPECIALLY OUTSIDE THE
DECAYING WEDGE REGION. GUSTS SHOULD EXCEED 20-25 KTS PERIODICALLY.
-GIH
TONIGHT AND TUESDAY:
SURFACE COLD FRONT IS EXPECTED TO QUICKLY MOVE ACROSS THE AREA LATE
TODAY INTO THIS EVENING WITH THE LOW LEVEL AIRMASS COMPLETELY
SCOURING OUT AS IT MOVES THROUGH. HOWEVER... WE WILL KEEP A LEAST
SOME MID AND HIGH LEVEL CLOUD COVER... ESPECIALLY ACROSS THE
SOUTH.... WHILE THE SURFACE FRONT STALLS TO THE SOUTH OF THE AREA.
EXPECT LOW TEMPS TONIGHT TO RANGE FROM AROUND 40 NW TO UPPER 40S
SE... WITH A WEST TO NORTHWESTERLY BREEZE AS SURFACE HIGH PRESSURE
BUILDS INTO THE REGION.
TUESDAY WILL START OFF WITH QUITE WEATHER. HOWEVER... A SOUTHERN
STREAM DISTURBANCE WILL BEGIN APPROACHING THE REGION FROM THE
SOUTHWEST ON TUESDAY... SPREADING MORE CLOUDS INTO THE AREA AND
PERHAPS SOME LIGHT RAIN ACROSS THE FAR SOUTHWEST LATE IN THE DAY.
HIGH TEMPS ARE AGAIN EXPECTED TO BE ABOVE NORMAL AS THE SYSTEM
APPROACHES FROM THE SOUTH AND SURFACE WINDS QUICKLY SWING BACK
AROUND TO WSW TO SOUTHWESTERLY IN ADVANCE OF THE DISTURBANCE.
THUS... WILL GO WITH HIGHS IN THE LOWER TO MID 60S. -BSD
&&
.SHORT TERM /TUESDAY NIGHT THROUGH WEDNESDAY NIGHT/...
AS OF 305 AM MONDAY...
TUESDAY NIGHT THROUGH WEDNESDAY NIGHT...
NEXT LOW PRESSURE SYSTEM IN THE ACTIVE SOUTHERN STREAM PROJECTED TO
TRAVERSE THE SOUTHERN PLAINS INTO THE LOWER MS VALLEY LATE TUE-TUE
NIGHT. THIS WEATHER SYSTEM WILL INDUCE THE FORMATION OF A SURFACE
LOW ON THE STALLED FRONT OVER THE NORTHERN GULF COAST BY LATE
TUESDAY. THE 00Z GFS TAKES THIS SURFACE WAVE NEWD UP THE SOUTHERN
APPALACHIANS THEN EWD ACROSS THE NC-VA PIEDMONT. 00Z ECMWF FITS INTO
THE CLASSICAL MODEL WITH THE WAVE PROGRESSING ENE ALONG A STALLED
SURFACE BOUNDARY ACROSS SOUTHERN AL-SOUTHERN GA THEN OFF THE
CAROLINA COASTS WHERE IT INTENSIFIES IN THE FAVORABLE BAROCLINIC
ZONE CAUSED BY THE GULF STREAM. INCREASING SLY FLOW AHEAD OF THE
SURFACE LOW WILL CAUSE AN OVERRUNNING PRECIP EVENT ACROSS CENTRAL NC
LATE TUESDAY NIGHT THROUGH WEDNESDAY EVENING. THE INCREASING
MOISTURE WILL ALSO BE LIFTED BY NOT ONLY THE MID-UPPER LEVEL S/W BUT
ALSO FROM A FAVORABLE JET CONFIGURATION WITH CENTRAL NC IN THE NOSE
OF 140+ KT JET. THUS...EXPECT WIDESPREAD RAIN TO OVERSPREAD CENTRAL
NC EARLY WED AND CONTINUE WELL INTO THE AFTERNOON. THE PRECIP AND
OVERCAST SKIES WILL RESULT IN BELOW NORMAL TEMPS WITH MAX TEMPS
HOLDING INT EH 40S ACROSS MOST OF THE PIEDMONT...AND THE LOWER 50S
IN THE FAR SOUTH-SE.
WEDNESDAY NIGHT...S/W CROSSES THE REGION IN THE EVENING THEN EXITS
THE COAST. DRIER WNW FLOW BEHIND THIS SYSTEM AS WELL AS SUBSIDENCE
WILL AID TO DISSIPATE CLOUD COVERAGE NW-SE DURING THE OVERNIGHT
HOURS. RESIDUAL MOISTURE MAY RESULT IN SOME AREAS OF FOG BUT
CONFIDENCE NOT HIGH ENOUGH AT THIS TIME TO INTRODUCE IN THE FORECAST
AS MAY BE ENOUGH MIXING TO PREVENT FOG FROM DEVELOPING. MIN TEMPS
MID-UPPER 30S.
&&
.LONG TERM /THURSDAY THROUGH SUNDAY/...
AS OF 305 AM MONDAY...
THURSDAY INTO FRIDAY...RELATIVELY TRANQUIL WEATHER PATTERN
ANTICIPATED AS BROAD TROUGH OVER THE EASTERN U.S. WILL CAUSE A WLY
FLOW THROUGH THE COLUMN OVER CENTRAL NC. THIS USUALLY YIELDS DRY
WEATHER WITH MILD TEMPS. LOW LEVEL THICKNESSES A SHADE ABOVE NORMAL
THU AND NEAR NORMAL FRI BUT WLY FLOW USUALLY ADDS ADDITIONAL
WARMING. AFTERNOON TEMPS IN THE 50S BOTH DAYS...APPROACHING 60 N THE
FAR SOUTH FRI.
BROAD UPPER TROUGH OVER EASTERN U.S. WILL UNDERGO AMPLIFICATION
SATURDAY INTO SUNDAY AS PACIFIC ENERGY IS SHUNTED WELL NWD INTO
ALASKA AND BRITISH COLUMBIA IN RESPONSE TO A STOUT UPPER LEVEL RIDGE
OVER THE WESTERN U.S. THIS ENERGY DIVES ON SEWD INTO THE NORTH
CENTRAL U.S. INITIATING THE AMPLIFICATION OF THE TROUGH. THIS WILL
CAUSE A MODIFIED ARCTIC AIR MASS TO SPREAD SEWD ACROSS MUCH OF THE
EASTERN U.S. THIS WEEKEND. THE LEADING EDGE OF THIS COLDER AIR WILL
SPREAD ACROSS CENTRAL NC FRI NIGHT INTO SATURDAY.
MODEL GUIDANCE CONTINUES TO EXHIBIT POSSIBLE SURFACE CYCLOGENESIS
ASSOCIATED WITH THIS AMPLIFICATION OFF THE EASTERN SEABOARD IN
VICINITY OF THE MID ATLANTIC COAST NWD TO NEW ENGLAND. CONSIDERING
THE STRENGTH OF THE DISTURBANCES ALOFT...MAY BE ENOUGH TO TRIGGER
SCATTERED SHOWERS ACROSS CENTRAL NC SATURDAY INTO SATURDAY EVENING.
PARTIAL THICKNESSES AND FORECAST GFS BUFKIT SOUNDINGS SUGGEST THAT
SNOW SHOWERS WOULD BE FAVORED OVER RAIN SHOWERS BUT MODELS MAY BE
COOLING OFF THE COLUMN TOO QUICKLY. SINCE WE ARE TALKING ABOUT DAY
6...PREFER TO MAINTAIN A SLIGHT CHANCE POP FOR NOW AND KEEP PRECIP
ALL LIQUID. HOWEVER DID BUMP UP CLOUDINESS A TAD AND LOWERED MAX
TEMPS SATURDAY 2-3 DEGREES FROM THE PREVIOUS FORECAST. MAX TEMPS
SATURDAY IN THE 40S TO NEAR 50 SOUTHEAST. IF PRECIP MORE EXTENSIVE
THAN CURRENT THINKING...MAX TEMPS COULD BE TOO WARM BY AS MUCH AS
5-6 DEGREES. BULK OF COLDER AIR WILL SETTLE OVER THE REGION SUNDAY
WITH MAX TEMPS 10-14 DEGREES BELOW NORMAL. MIN TEMPS SUN MORNING IN
THE 20S.
&&
.AVIATION /18Z MONDAY THROUGH SATURDAY/...
AS OF 120 PM TUESDAY...
LIFR CONDITIONS WILL PERSIST FOR ANOTHER FEW HOURS AT INT/GSO...
WHILE IFR/MVFR CIGS WITH VFR VSBYS WILL HOLD ELSEWHERE. A WEDGE
BOUNDARY REMAINS TO THE SE OF INT/GSO... AND THE LIFR CIGS AND VSBYS
AROUND 1 SM HAVE BUDGED LITTLE SO FAR TODAY. EXPECT CIGS TO SLOWLY
LIFT EVERYWHERE BUT IMPROVE TO NO BETTER THAN MVFR THROUGH 23Z. CIGS
ARE EXPECTED TO RISE TO VFR 01Z-04Z AS A COLD FRONT MOVES EAST
THROUGH THE AREA... AND SWRLY SURFACE WINDS SHIFT AROUND TO WSW THEN
FROM THE WEST AS A COLD FRONT MOVES THROUGH THE AREA... BEFORE
SETTLING JUST TO OUR SOUTH OVERNIGHT. WINDS WILL APPROACH LLWS
CRITERIA THROUGH THIS AFTERNOON AS SPEEDS AT 2 THOUSAND FT AGL WILL
REMAIN FROM THE SW AT 35-40 KTS... BUT THE EXIT OF THE LOW LEVEL JET
WILL CAUSE WINDS ALOFT TO DECREASE TO 25-35 KTS BY 00Z. THE
INCREASING WINDS WITH HEIGHT MAY STILL CAUSE ISSUES WITH MECHANICAL
TURBULENCE THROUGH THIS EVENING HOWEVER. VFR CIGS WILL HOLD FROM
AROUND MIDNIGHT THROUGH TUESDAY MORNING AS WEAK HIGH PRESSURE BUILDS
IN.
LOOKING BEYOND 18Z TUESDAY... VFR CIGS WILL HOLD INTO TUESDAY
EVENING BUT THEN DROP BACK DOWN TO IFR/LIFR OVERNIGHT AS A WAVE OF
LOW PRESSURE TRACKS ALONG THE FRONT STALLED JUST TO OUR SOUTH. THESE
POOR AVIATION CONDITIONS SHOULD HOLD THROUGH WEDNESDAY BEFORE
IMPROVING TO VFR WEDNESDAY EVENING AS THE LOW EXITS. VFR CONDITIONS
WILL THEN HOLD UNTIL SATURDAY... WHEN WE COULD SEE ANOTHER STORM
SYSTEM BRINGING SUB-VFR CONDITIONS. -GIH
&&
.RAH WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...HARTFIELD
NEAR TERM...HARTFIELD/BSD
SHORT TERM...WSS
LONG TERM...WSS
AVIATION...HARTFIELD
AREA FORECAST DISCUSSION
NWS RALEIGH NC
950 AM EST MON FEB 11 2013
.SYNOPSIS...
A WARM FRONT WILL CONTINUE MOVING NORTHWARD THROUGH THE AREA TODAY.
A COLD FRONT WILL CROSS THE REGION THIS EVENING BEFORE SETTLING JUST
TO OUR SOUTH... THEN WEAK HIGH PRESSURE WILL MOVE IN LATE TONIGHT
THROUGH TUESDAY. A LOW PRESSURE SYSTEM WILL TRACK ALONG THE FRONT
AND AFFECT THE AREA ON WEDNESDAY.
&&
.NEAR TERM /THROUGH TUESDAY/...
AS OF 950 AM MONDAY...
REST OF TODAY: MAIN CONCERNS THIS MORNING ARE DEALING WITH THE
DEPARTING RAIN... WIDELY VARYING TEMPS... AND WIND. WEDGE REGIME
REMAINS WELL-ENTRENCHED OVER THE FAR NRN AND NW PIEDMONT...
BISECTING THE TRIAD REGION WITH 9 AM TEMPS IN THE UPPER 50S IN
ASHEBORO WHILE LOWER 40S HOLD AT LEXINGTON WITH FOG/STRATUS AND VERY
LIGHT TO CALM AIR. THE 12Z GSO SOUNDING SHOWS A FORMIDABLE STABLE
LAYER (+4C DIFFERENTIAL FROM SURFACE TO WARM NOSE ALOFT) WITH DEEP
SATURATION... AND EVEN OUTSIDE OF THIS DEFINED WEDGE... DESPITE THE
MILDER TEMPS IN THE 50S... THE LOW LEVELS (UNDER 900 MB) REMAIN
NEUTRAL TO SLIGHTLY STABLE AS NOTED BY RECENT AMDAR AIRCRAFT
SOUNDINGS NEAR RDU. WINDS HERE ARE BEGINNING TO PICK UP OUT OF THE
SOUTH AND SW THOUGH... INDICATING THAT IMPROVED LOW LEVEL MIXING IS
IMMINENT. THE WIDESPREAD LIGHT RAIN IS ON ITS WAY OUT A BIT MORE
QUICKLY THAN EARLIER ANTICIPATED... HOWEVER WITH BLENDED TPW IMAGERY
SHOWING PRECIP WATER VALUES OVER 200 PERCENT OF NORMAL ACROSS THE
ENTIRE REGION... THE RISK OF PATCHY SHOWERS WILL REMAIN FOR ANOTHER
SEVERAL HOURS AS THE MOIST COLUMN WILL STAY VULNERABLE TO EVEN
SUBTLE FORCING FOR ASCENT. WILL HOLD ONTO SMALL POPS MAINLY S/E OF
THE TRIAD INTO THE AFTERNOON. LOW CLOUDS SHOULD HOLD IN EVERYWHERE
UNTIL MID AFTERNOON WITH THE CONTINUED LOW-MID LEVEL FLOW FROM THE
SW ELIMINATING THE POTENTIAL FOR SIGNIFICANT DOWNSLOPE DRYING UNTIL
LATE... WHEN THE MID LEVEL PERTURBATION NOW OVER NW NC MOVES OFF THE
COAST. TEMPS ARE ALWAYS TOUGH TO GAUGE IN THESE WEDGE SITUATIONS
ESPECIALLY WHEN THERE IS NO LONGER A FEED OF LOW LEVEL DRY AIR TO
MAINTAIN THE STABLE POOL. ALL FINE-RESULTION GUIDANCE INCLUDING THE
LOCAL WRF AND HRRR FAVORS A MIXING-OUT OF THE REMAINING WEDGE OVER
OUR NW CWA BY EARLY AFTERNOON... ALTHOUGH THE ABUNDANT THICK CLOUDS
FOR MUCH OF THE DAY WILL CUT DOWN ON WARMING ALL ACROSS THE AREA.
NEVERTHELESS.... ANOMALOUSLY WARM THICKNESSES WILL RISE FURTHER THIS
AFTERNOON... AND STILL EXPECT HIGHS IN THE MID 60S TO NEAR 70 OVER
MUCH OF THE CWA EXCEPT FOR NEAR 60 IN THE NW CORNER. SINCE WE WON`T
FULLY MIX UP BEYOND 900 MB UNTIL LATE IN THE DAY... WHEN THE 50-60
KT LOW LEVEL JET WILL HAVE EXITED... OUR WIND GUSTS WILL REMAIN WELL
BELOW ADVISORY THRESHOLD... YET WE SHOULD STILL SEE GUSTS BECOME
MORE FREQUENT AND HIGHER THIS AFTERNOON ESPECIALLY OUTSIDE THE
DECAYING WEDGE REGION. GUSTS SHOULD EXCEED 20-25 KTS PERIODICALLY.
-GIH
TONIGHT AND TUESDAY:
SURFACE COLD FRONT IS EXPECTED TO QUICKLY MOVE ACROSS THE AREA LATE
TODAY INTO THIS EVENING WITH THE LOW LEVEL AIRMASS COMPLETELY
SCOURING OUT AS IT MOVES THROUGH. HOWEVER... WE WILL KEEP A LEAST
SOME MID AND HIGH LEVEL CLOUD COVER... ESPECIALLY ACROSS THE
SOUTH.... WHILE THE SURFACE FRONT STALLS TO THE SOUTH OF THE AREA.
EXPECT LOW TEMPS TONIGHT TO RANGE FROM AROUND 40 NW TO UPPER 40S
SE... WITH A WEST TO NORTHWESTERLY BREEZE AS SURFACE HIGH PRESSURE
BUILDS INTO THE REGION.
TUESDAY WILL START OFF WITH QUITE WEATHER. HOWEVER... A SOUTHERN
STREAM DISTURBANCE WILL BEGIN APPROACHING THE REGION FROM THE
SOUTHWEST ON TUESDAY... SPREADING MORE CLOUDS INTO THE AREA AND
PERHAPS SOME LIGHT RAIN ACROSS THE FAR SOUTHWEST LATE IN THE DAY.
HIGH TEMPS ARE AGAIN EXPECTED TO BE ABOVE NORMAL AS THE SYSTEM
APPROACHES FROM THE SOUTH AND SURFACE WINDS QUICKLY SWING BACK
AROUND TO WSW TO SOUTHWESTERLY IN ADVANCE OF THE DISTURBANCE.
THUS... WILL GO WITH HIGHS IN THE LOWER TO MID 60S. -BSD
&&
.SHORT TERM /TUESDAY NIGHT THROUGH WEDNESDAY NIGHT/...
AS OF 305 AM MONDAY...
TUESDAY NIGHT THROUGH WEDNESDAY NIGHT...
NEXT LOW PRESSURE SYSTEM IN THE ACTIVE SOUTHERN STREAM PROJECTED TO
TRAVERSE THE SOUTHERN PLAINS INTO THE LOWER MS VALLEY LATE TUE-TUE
NIGHT. THIS WEATHER SYSTEM WILL INDUCE THE FORMATION OF A SURFACE
LOW ON THE STALLED FRONT OVER THE NORTHERN GULF COAST BY LATE
TUESDAY. THE 00Z GFS TAKES THIS SURFACE WAVE NEWD UP THE SOUTHERN
APPALACHIANS THEN EWD ACROSS THE NC-VA PIEDMONT. 00Z ECMWF FITS INTO
THE CLASSICAL MODEL WITH THE WAVE PROGRESSING ENE ALONG A STALLED
SURFACE BOUNDARY ACROSS SOUTHERN AL-SOUTHERN GA THEN OFF THE
CAROLINA COASTS WHERE IT INTENSIFIES IN THE FAVORABLE BAROCLINIC
ZONE CAUSED BY THE GULF STREAM. INCREASING SLY FLOW AHEAD OF THE
SURFACE LOW WILL CAUSE AN OVERRUNNING PRECIP EVENT ACROSS CENTRAL NC
LATE TUESDAY NIGHT THROUGH WEDNESDAY EVENING. THE INCREASING
MOISTURE WILL ALSO BE LIFTED BY NOT ONLY THE MID-UPPER LEVEL S/W BUT
ALSO FROM A FAVORABLE JET CONFIGURATION WITH CENTRAL NC IN THE NOSE
OF 140+ KT JET. THUS...EXPECT WIDESPREAD RAIN TO OVERSPREAD CENTRAL
NC EARLY WED AND CONTINUE WELL INTO THE AFTERNOON. THE PRECIP AND
OVERCAST SKIES WILL RESULT IN BELOW NORMAL TEMPS WITH MAX TEMPS
HOLDING INT EH 40S ACROSS MOST OF THE PIEDMONT...AND THE LOWER 50S
IN THE FAR SOUTH-SE.
WEDNESDAY NIGHT...S/W CROSSES THE REGION IN THE EVENING THEN EXITS
THE COAST. DRIER WNW FLOW BEHIND THIS SYSTEM AS WELL AS SUBSIDENCE
WILL AID TO DISSIPATE CLOUD COVERAGE NW-SE DURING THE OVERNIGHT
HOURS. RESIDUAL MOISTURE MAY RESULT IN SOME AREAS OF FOG BUT
CONFIDENCE NOT HIGH ENOUGH AT THIS TIME TO INTRODUCE IN THE FORECAST
AS MAY BE ENOUGH MIXING TO PREVENT FOG FROM DEVELOPING. MIN TEMPS
MID-UPPER 30S.
&&
.LONG TERM /THURSDAY THROUGH SUNDAY/...
AS OF 305 AM MONDAY...
THURSDAY INTO FRIDAY...RELATIVELY TRANQUIL WEATHER PATTERN
ANTICIPATED AS BROAD TROUGH OVER THE EASTERN U.S. WILL CAUSE A WLY
FLOW THROUGH THE COLUMN OVER CENTRAL NC. THIS USUALLY YIELDS DRY
WEATHER WITH MILD TEMPS. LOW LEVEL THICKNESSES A SHADE ABOVE NORMAL
THU AND NEAR NORMAL FRI BUT WLY FLOW USUALLY ADDS ADDITIONAL
WARMING. AFTERNOON TEMPS IN THE 50S BOTH DAYS...APPROACHING 60 N THE
FAR SOUTH FRI.
BROAD UPPER TROUGH OVER EASTERN U.S. WILL UNDERGO AMPLIFICATION
SATURDAY INTO SUNDAY AS PACIFIC ENERGY IS SHUNTED WELL NWD INTO
ALASKA AND BRITISH COLUMBIA IN RESPONSE TO A STOUT UPPER LEVEL RIDGE
OVER THE WESTERN U.S. THIS ENERGY DIVES ON SEWD INTO THE NORTH
CENTRAL U.S. INITIATING THE AMPLIFICATION OF THE TROUGH. THIS WILL
CAUSE A MODIFIED ARCTIC AIR MASS TO SPREAD SEWD ACROSS MUCH OF THE
EASTERN U.S. THIS WEEKEND. THE LEADING EDGE OF THIS COLDER AIR WILL
SPREAD ACROSS CENTRAL NC FRI NIGHT INTO SATURDAY.
MODEL GUIDANCE CONTINUES TO EXHIBIT POSSIBLE SURFACE CYCLOGENESIS
ASSOCIATED WITH THIS AMPLIFICATION OFF THE EASTERN SEABOARD IN
VICINITY OF THE MID ATLANTIC COAST NWD TO NEW ENGLAND. CONSIDERING
THE STRENGTH OF THE DISTURBANCES ALOFT...MAY BE ENOUGH TO TRIGGER
SCATTERED SHOWERS ACROSS CENTRAL NC SATURDAY INTO SATURDAY EVENING.
PARTIAL THICKNESSES AND FORECAST GFS BUFKIT SOUNDINGS SUGGEST THAT
SNOW SHOWERS WOULD BE FAVORED OVER RAIN SHOWERS BUT MODELS MAY BE
COOLING OFF THE COLUMN TOO QUICKLY. SINCE WE ARE TALKING ABOUT DAY
6...PREFER TO MAINTAIN A SLIGHT CHANCE POP FOR NOW AND KEEP PRECIP
ALL LIQUID. HOWEVER DID BUMP UP CLOUDINESS A TAD AND LOWERED MAX
TEMPS SATURDAY 2-3 DEGREES FROM THE PREVIOUS FORECAST. MAX TEMPS
SATURDAY IN THE 40S TO NEAR 50 SOUTHEAST. IF PRECIP MORE EXTENSIVE
THAN CURRENT THINKING...MAX TEMPS COULD BE TOO WARM BY AS MUCH AS
5-6 DEGREES. BULK OF COLDER AIR WILL SETTLE OVER THE REGION SUNDAY
WITH MAX TEMPS 10-14 DEGREES BELOW NORMAL. MIN TEMPS SUN MORNING IN
THE 20S.
&&
.AVIATION /12Z MONDAY THROUGH FRIDAY/...
AS OF 640 AM TUESDAY...
24 HOUR TAF PERIOD:
ADVERSE AVIATION CONDITIONS EXPECTED TODAY... WITH SUB-VFR
CONDITIONS AND GUSTY WINDS POSSIBLE.
LIGHT RAIN AND DRIZZLE ARE FILLING IN ACROSS CENTRAL NC AGAIN THIS
MORNING... WITH ALONG WITH A MORE DEFINED IN-SITU COLD AIR DAMMING
WEDGE AIRMASS PARKED ACROSS THE AREA. AT KFAY THE WARM FRONT HAS
SURGE TO THE NORTH OF THE AREA... WITH THE CAD BOUNDARY GENERALLY
EXTENDING FROM JUST SOUTH OF KEXX (LEXINGTON) EASTWARD TO THE
NORTHERN COASTAL PLAIN. LOW CIGS WITH GENERALLY LIGHT AND VARIABLE
RAIN ARE COMMON ON THE NORTHERN SIDE OF THE BOUNDARY... WITH
SOUTHERLY WINDS IN THE 10 TO 15 KT RANGE... WITH GUSTS OF UP TO
20-25 KTS POSSIBLE SOUTH OF THE BOUNDARY WITH GENERALLY MVFR CIGS
(WITH RAIN STILL). THIS LATEST AREA OF RAIN IS EXPECTED TO MOVE
ACROSS MOST OF THE AREA OVER THE NEXT 3-5 HOURS. THIS MAY HELP DELAY
THE EROSION OF THE CAD AIRMASS AT KRDU AND KRWI BY A FEW HOURS.
THUS... HAVE DELAYED CONDITIONS IMPROVING AND ARRIVE OF THE GUSTY
WINDS... AND THUS EXTENDED THE THREAT OF LLWS AS SOUTHWESTERLY WINDS
OF 40-45 KTS A COUPLE THOUSAND FEET OFF OF THE SURFACE WILL CONTINUE
ACROSS CENTRAL NC THROUGH EARLY AFTERNOON. THUS... BY 16Z OR SO
EXPECT WINDS TO INCREASE AT KRDU AND KRWI OUT OF THE SOUTHWEST...
WITH GUSTS IN THE 20 TO 25 KT RANGE FOR THE AFTERNOON. FURTHER WEST
WE MAY NOT SEE THE STABLE AIRMASS BREAK UNTIL EARLY TO MID
AFTERNOON. THUS... HAVE PUSHED BACK THE TIMING A BIT... WITH MVFR
CIGS NOT EXPECTED UNTIL AFTERNOON... ALONG WITH THE GUSTY
SOUTHWESTERLY WINDS. AT KFAY... EXPECT WE WILL SEE THE WIND GUSTS IN
THE 20 TO 25 KT RANGE... WITH EVEN 30 KTS NOT OUT OF THE QUESTION IF
CIGS INCREASE ENOUGH BEFORE THE CORE OF THE LOW LEVEL JET SHIFTS TO
THE EAST THIS AFTERNOON. OTHERWISE EXPECT ON AN OFF RAIN MOST OF THE
DAY (FOR KFAY)... WITH GENERALLY MVFR CIGS... TO AT TIMES IFR.
A COLD FRONT WILL MOVE ACROSS THE AREA LATE IN THE DAY AND SCOUR OUR
ANY LINGERING LOW LEVEL CLOUD COVER.... ALLOWING A RETURN TO VFR
CONDITIONS BY AROUND 03Z OR SO. VFR CONDITIONS ARE THEN EXPECTED TO
CONTINUE FOR THE REST OF THE TAF PERIOD.
LOOKING AHEAD:
VFR CONDITIONS SHOULD PREVAIL THROUGH TUESDAY EVENING BUT THEN A
SHORTWAVE SYSTEM COULD BRING SUB VFR CONDITIONS FOR WEDNESDAY AND
WEDNESDAY NIGHT. CONDITIONS ARE EXPECTED TO RETURN TO VFR AND HOLD
THERE THROUGH THE REST PERIOD.
&&
.RAH WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...HARTFIELD
NEAR TERM...HARTFIELD/BSD
SHORT TERM...WSS
LONG TERM...WSS
AVIATION...BSD
AREA FORECAST DISCUSSION
NWS NEWPORT/MOREHEAD CITY NC
359 AM EST MON FEB 11 2013
.SYNOPSIS...
A WARM FRONT WILL LIFT NORTH THROUGH THE AREA THIS MORNING AS A COLD FRONT
PUSHES EAST THROUGH THE AREA AND OFFSHORE BY TONIGHT. A LOW PRESSURE AREA
WILL MOVE NORTHEAST ALONG THE COAST WEDNESDAY...FOLLOWED BY HIGH
PRESSURE FOR THURSDAY AND FRIDAY. ANOTHER COLD FRONT WILL MOVE THROUGH
THE AREA FRIDAY NIGHT.
&&
.NEAR TERM /TODAY/...
AS OF 350 AM MONDAY...ONLY SOME VERY LIGHT PRECIPITATION IS
REACHING THE GROUND OVER THE MHX CWA. THE LATEST RAP MODEL STILL
SHOWS PRECIPITATION BECOMING MORE WIDESPREAD AFTER 12Z AND WILL
CONTINUE TO RAMP UP POPS THROUGH THE EARLY MORNING HOURS...BECOMING
CATEGORICAL AFTER 12Z. WARM FRONT CONTINUE TO MOVE NORTH THROUGH
THE CWA WITH MOST TEMPERATURES NOW IN THE LOWER TO MIDDLE 50S WITH
62 DEGREES AT CAPE HATTERAS. WITH A FAIRLY DEEP SOUTHERLY
FLOW...EXPECT TEMPERATURES TO RISE INTO THE MIDDLE AND UPPER 60S
OVER MOST AREAS WITH A FEW SPOTS OVER THE SOUTHERN COUNTIES
PERHAPS TOUCHING 70 DEGREES. THINK MOST OF THE WIDESPREAD
PRECIPITATION WILL OCCUR BEFORE 18Z...WITH RAIN BECOMING MORE
SCATTERED AFTER 18Z. LATEST NAM12 AND GFS SHOW A RIBBON OF
INSTABILITY POSITIONING ITSELF JUST OFFSHORE BY LATER TODAY AND
HAVE INCLUDED A SLIGHT CHANCE OF THUNDER FOR THE COASTAL WATERS.
&&
.SHORT TERM /TONIGHT/...
AS OF 355 AM MONDAY...PRECIPITATION WILL TAPER FROM NORTH TO SOUTH
TONIGHT WITH MINIMAL RAIN CHANCES EXPECTED AFTER MIDNIGHT AS DRIER
AIR FILTERS INTO THE REGION FROM THE NORTH. CLOUDINESS WILL
LIKEWISE DECREASE AS WE HEAD TOWARD THE MORNING HOURS. MINIMUM
TEMPERATURES ACROSS THE AREA WILL RANGE FROM 45 TO 50 DEGREES.
&&
.LONG TERM /TUESDAY THROUGH SUNDAY/...
AS OF 340 AM MON...UPPER LEVEL TROUGH OVER THE EASTERN GREAT
LAKES WILL CONTINUE TO PUSH NE INTO QUEBEC ON TUES WHILE BROAD AND
WEAK UPPER RIDGING ESTABLISHES ITSELF ACROSS FL/GULF OF MEXICO.
THESE FEATURES WILL PRODUCE WESTERLY FLOW ALOFT. SURFACE HIGH
PRESSURE NORTH OF THE AREA WILL MOVE INTO THE REGION TUES BRINGING
WARM TEMPS INTO EASTERN NC...WITH HIGHS IN THE LOW/MID 60S.
MONDAY`S COLD FRONT WILL REMAIN STALLED OFF THE SE COAST WITH AN
AREA OF LOW PRESSURE FORMING ALONG THE BOUNDARY OVER THE SE STATES
TUES NIGHT INTO WED MORNING.
GREATER DIFFERENCES EXIST BETWEEN THE 00Z RUNS OF THE GFS AND ECMWF
WITH THE SURFACE LOW TRACK FARTHER INLAND WITH THE GFS SCENARIO
WHILE THE ECMWF LOW TRACKS ALONG THE COAST...SIMILAR TO PREVIOUS
RUNS. THE GFS IS ALSO STRONGER WITH THE MIDLEVEL SHORTWAVE DIGGING
SOUTHEAST ACROSS THE SOUTHERN STATES. HEDGED SLIGHTLY CLOSER TO
THE GFS GIVEN ITS OPERATIONAL SUPPORT WITH THE GFS ENSEMBLE. THIS
WILL MEAN SLIGHTLY MORE QPF BUT A CONTINUATION OF HIGH POPS TO
CATEGORICAL BY WED ACROSS SOUTHERN HALF OF THE CWA. EXPECT PRECIP
TO END FROM WEST TO EAST LATE WED NIGHT AS THE SURFACE LOW PUSHES
NE INTO THE NORTHERN ATLANTIC OCEAN. STRONG SHORTWAVE ALOFT WILL
ALSO PUSH THROUGH THE REGION WED NIGHT...WITH RIDGING SURFACE AND
ALOFT BUILDING INTO EASTERN NC THURS. THE HIGH WILL PUSH OFFSHORE
FRI. TEMPS WILL BE NEAR CLIMO THURS AND FRI.
BY EARLY WEEKEND IT APPEARS MORE LIKELY THAT AN ARCTIC AIRMASS WILL
INVADE THE EASTERN CONUS AS BOTH GFS/ECMWF INDICATE DEEP TROUGHING
ALOFT...AND CONTINUED TO HEDGE CLOSER TO THE ECMWF FOR LATE IN THE
EXTENDED. THERE COULD BE SOME SHOWERS SAT AHEAD OF THE ARCTIC
COLD FRONT...AND WILL MAINTAIN SLIGHT CHANCE POPS. SUN WILL BE QUITE
A BIT COLDER WITH HIGHS IN THE LOW/MID 40S.
&&
.AVIATION /08Z MONDAY THROUGH FRIDAY/...
SHORT TERM /THROUGH MONDAY/...
AS OF 1245 AM MONDAY...ONLY MADE MINOR TIMING ADJUSTMENTS FOR THE
LATEST TAF CYCLE. LOW-LEVEL MOISTURE WILL CONTINUE TO PUSH INTO
EASTERN NORTH CAROLINA AS A WARM FRONT LIFTS TO THE NORTH THIS
MORNING. PER LATEST 4 KM WRF AND RAP MODELS...LIGHT RAIN SHOULD
BECOME WIDESPREAD BY AROUND 12Z. AS A COLD FRONT THEN MOVES ACROSS
THE AREA...RAIN WILL PERSIST INTO THE EVENING BEFORE THE FRONT
SHIFTS OFFSHORE. A STRONG LLJ WILL DEVELOP...SO EXPECT GUSTY WINDS
TO INCREASE MONDAY MORNING THROUGH THE AFTERNOON. CROSSWINDS WILL
BE AN ISSUE FOR SITES USING A E-W OR NW-SE ORIENTED RUNWAY. RAINS
WILL CONTINUE ALL DAY WITH CEILINGS FLIRTING NEAR OR JUST BELOW
IFR.
LONG TERM /MONDAY NIGHT THROUGH THURSDAY/...
AS OF 340 AM MON...EXPECT PREDOMINANT VFR CONDITIONS TUES AS HIGH
PRESSURE BUILDS SOUTH OVER THE TERMINALS. SUB-VFR EXPECTED LATE
TUES NIGHT AS AN AREA OF LOW PRESSURE DEVELOPS TO THE SW AND MOVES
NE OVER EASTERN NC. ADDITIONAL PRECIP WITH LOWERED CEILINGS AND
VSBYS POSSIBLE ON WED. RETURN TO VFR EXPECTED THURS AS HIGH
PRESSURE BUILDS ACROSS EASTERN NC.
&&
.MARINE...
SHORT TERM /THROUGH MONDAY/...
AS OF 355 AM MONDAY...AS WARM FRONT LIFTS NORTH OF THE
REGION...GUSTY SOUTH TO SOUTHWEST WINDS WILL DEVELOP THIS MORNING
WITH 20 TO 25 KNOT SPEEDS LIKELY BY AROUND MID-MORNING. PER LATEST
LOCAL NWPS MODEL...WILL SEE SEAS INCREASE TO AS HIGH AS 11 FEET
OVER SOME OF THE CENTRAL AND NORTHERN WATERS TODAY INTO TONIGHT.
THE WINDS WILL BECOME MORE W/WNW BEHIND THE FRONT AS IT MOVES
OFFSHORE LATER TONIGHT AND SHOULD GRADUALLY SUBSIDE TOWARD
MORNING. GIVEN GOOD CONSISTENCY IN MODEL WIND FIELDS...NO CHANGES
HAVE BEEN MADE TO CURRENT SMALL CRAFT ADVISORIES.
LONG TERM /MONDAY NIGHT THROUGH FRIDAY/...
AS OF 345 AM MON...HIGH PRESSURE BUILDS IN FOR TUES BRINGING GOOD
BOATING CONDITIONS. WEAK LOW PRES WILL DEVELOP DURING THE DAY
WED SW OF THE NC COASTAL WATERS. THIS WILL BRING EASTERLY WINDS TO
START ACROSS THE AREA. CONDITIONS LOOK TO REMAIN SUB SCA HOWEVER
ON WED. DURING THE AFTERNOON WED...AS THE LOW PULLS EASTWARD...
WINDS WILL SWITCH TO THE WEST AND THEN NORTHWEST BY EVENING. EXPECT
A BRIEF PERIOD OF 15-25 KT WINDS AND SEAS 6-8 FT WED NIGHT INTO
EARLY THUR. HIGH PRESSURE WILL BE IN CONTROL FOR THE REMAINDER OF
THE WEEK BRINGING GOOD BOATING CONDITIONS. LOCAL SWAN/NWPS IN GOOD
SHAPE THROUGH THURS THEN BLENDED PREVIOUS SEAS FORECAST WITH LATEST
WAVEWATCH III GUIDANCE THURS NIGHT AND FRI WITH NO MAJOR CHANGES.
&&
.MHX WATCHES/WARNINGS/ADVISORIES...
NC...NONE.
MARINE...SMALL CRAFT ADVISORY FROM 7 AM THIS MORNING TO 10 PM EST THIS
EVENING FOR AMZ135.
SMALL CRAFT ADVISORY FROM 7 AM THIS MORNING TO 7 PM EST THIS
EVENING FOR AMZ130.
SMALL CRAFT ADVISORY UNTIL 10 AM EST TUESDAY FOR AMZ152-154.
SMALL CRAFT ADVISORY UNTIL 7 AM EST TUESDAY FOR AMZ156-158.
SMALL CRAFT ADVISORY UNTIL 4 AM EST TUESDAY FOR AMZ150.
&&
$$
SYNOPSIS...CTC
NEAR TERM...CTC
SHORT TERM...CTC
LONG TERM...DAG
AVIATION...CTC/DAG
MARINE...CTC/DAG
AREA FORECAST DISCUSSION
NWS NEWPORT/MOREHEAD CITY NC
1248 AM EST MON FEB 11 2013
.SYNOPSIS...
HIGH PRESSURE WILL CONTINUE MOVING OFFSHORE TONIGHT AND A WARM FRONT
WILL LIFT NORTH THROUGH THE AREA LATE TONIGHT. A COLD FRONT WILL
SLOWLY MOVE THROUGH THE AREA MONDAY AND PUSH OFFSHORE MONDAY
NIGHT...STALLING JUST SOUTH OF THE AREA TUESDAY. A LOW PRESSURE AREA
WILL MOVE NORTHEAST ALONG THE COAST WEDNESDAY...FOLLOWED BY HIGH
PRESSURE FOR THURSDAY AND FRIDAY. A COLD FRONT WILL MOVE THROUGH THE
AREA FRIDAY NIGHT.
&&
.NEAR TERM /UNTIL 6 AM THIS MORNING/...
AS OF 1240 AM MONDAY...WARM FRONT LIES JUST OFF OUR SOUTHERN COAST
AS OF 05Z WITH TEMPERATURES IN THE 60S AT FRYING PAN BUOY AND AT
THE BUOY 30 MILES SOUTHEAST OF NEW RIVER. MEANWHILE...TEMPERATURES
GENERALLY IN THE MIDDLE 40S TO AROUND 50 OVER LAND AREAS. THE WARM
FRONT WILL PIVOT TO THE NORTH OF THE REGION WITH TEMPERATURES
SLOWLY RISING THROUGH THE EARLY MORNING HOURS. THE LEADING EDGE
OF THE RAIN SHIELD IS JUST NOW REACHING OUR FAR WESTERN COUNTIES.
PER LATEST 4 KM WRF AND RAP MODELS...THE PRECIPITATION SHOULD
BECOME MORE WIDESPREAD AFTER ABOUT 11Z OR 12Z. CURRENT FORECAST ON
TRACK WITH POPS RAMPING UP TOWARD MORNING.
&&
.SHORT TERM /6 AM THIS MORNING THROUGH 6 PM TUESDAY/...
AS OF 300 PM SUNDAY...PER NEAR TERM...MODELS REMAIN IN DECENT
AGREEMENT FOR PERIOD...AND NO SIGNIFICANT CHANGES TO PREVIOUS FCST.
STRONG WAA EXPECTED TO PRODUCE WDSPRD PCPN EVENT...BUT ENOUGH MODEL
DIFFERENCES ON QPF TO LIMIT CONFIDENCE IN GOING WITH 100% POPS. ALSO
WILL NOT INTRODUCE MENTION OF TSTMS AS LACK OF INSTABILITY EXPECTED
TO LIMIT CONVECTION. EVEN WITH CLOUDS AND PCPN...STRONG S-SW FLOW
WILL ALLOW MAX TEMPS TO REACH INTO MID-UPR 60S.
&&
.LONG TERM /TUESDAY NIGHT THROUGH SUNDAY/...
AS OF 330 PM SUN...MEDIUM TO LONG TERM PERIOD WILL CONTINUE TO FAVOR
MORE CONSISTENT ECMWF. THE PERIOD WILL START OUT DRY WITH HIGH
PRESSURE FOR TUESDAY...FOLLOWED BY INCREASING RAIN CHANCES LATE TUE
NIGHT AND CONTINUING THROUGH WED...THEN A DRY PERIOD FOR THE END OF
THE WEEK. SHARPLY COLDER TEMPS EXPECTED FOR THE SECOND HALF OF THE
WEEKEND.
FOR MON NIGHT...SOME LINGERING SHOWERS WILL ACCOMPANY COOL FRONT
DROPPING SOUTH THROUGH EASTERN NC...ESP FOR THE SOUTHERN HALF OF THE
FA. HAVE RAISED POPS A BIT HERE ACCORDINGLY TO FALL MORE IN LINE
WITH ECM MOS. VERY DRY HIGH PRES WILL MOVE INTO THE REGION TUE. THE
DRYING WILL BE AIDED BY COMPRESSIONAL 850MB WNW FLOW OFF THE SRN
APPALACHIANS. THIS WILL ALSO BRING WARM TEMPS INTO E NC...WITH HIGHS
IN THE LOW TO MID 60S. THE LIMITING FACTOR FOR SERIOUS FIRE WEATHER
CONCERNS WILL BE THE LIGHT SFC WINDS...ONLY ON ORDER OF 5 TO 10 KT.
BOUNDARY LAYER WILL BE QUITE DRY TO START TUE NIGHT...THOUGH BY LATE
NIGHT THE AREA WILL BE UNDER THE NOSE OF A FAIRLY STRONG SWLY LLJ.
ISENTROPIC LIFT WILL INCREASE QUITE DRASTICALLY AFTER AROUND 06Z...
AND INHERITED LIKELY POPS STILL LOOK GOOD FOR SOUTHERN TWO THIRDS OF
THE FA.
WEAK SFC CYCLOGENESIS OCCURS DURING THE DAY WED ACROSS SRN COASTAL
WATERS...KEEPING THE FCST AREA IN THE COOL SECTOR. HAVE BROUGHT
TEMPS DOWN 5 TO 7 DEGREES FOR HIGHS WED DUE TO LOW LEVEL NNE FLOW
AND PLENTIFUL LOW CLOUDS AND LIGHT PRECIP. ECM MOS WAS PREFERRED
OVER GFS MOS...AS GFS WAS ON THE WARM SIDE WITH SFC LOW A BIT
FURTHER NORTH. LOOKS TO BE A HIGH POP/LOW QPF EVENT WITH WEAK UPR
LEVEL SUPPORT...AND MUCH OF THE LIFT WILL BE CONFINED BELOW 700MB.
ORGANIZED SHOWERS MOVE EAST WED EVENING WITH DEPARTING SFC LOW...
THOUGH COULD SEE SOME REMAINING ISOLATED SHOWERS AS MID LEVEL
SHORTWAVE SWINGS THROUGH. HIGH PRES WILL BUILD IN FOR THUR AND FRI
BRINGING DRY CONDITIONS AND NEAR NORMAL TEMPS.
LOOKING AHEAD TO THE WEEKEND...IT IS LOOKING MORE LIKELY THAT AN
ARCTIC AIRMASS WILL INVADE THE EASTERN CONUS AS BOTH GFS/EMWF AND
THEIR ENSEMBLE MEAN HEIGHT FIELDS INDICATE DEEP TROUGHING IN THE
EAST. SIDED WITH THE ECMWF FOR TIMING...AS GFS IS ABOUT 24 FASTER.
THE ECM HAS SUPPORT FROM ITS ENSEMBLE MEAN HEIGHT FIELDS WHICH HAS
BETTER CLUSTERING BEYOND THE 156 HOUR TIME FRAME. THERE COULD BE
SOME SHOWERS SATURDAY AHEAD OF THE ARCTIC COLD FRONT...THOUGH THIS
FAR OUT WILL NOT INTRODUCE HIGHER THAN SLIGHT CHANCE POPS. SUNDAY
WILL BE QUITE A BIT COLDER WITH HIGH STRUGGLING INTO THE 40S.
&&
.AVIATION /06Z MONDAY THROUGH FRIDAY/...
SHORT TERM /THROUGH MONDAY/...
AS OF 1245 AM MONDAY...ONLY MADE MINOR TIMING ADJUSTMENTS FOR THE
LATEST TAF CYCLE. LOW-LEVEL MOISTURE WILL CONTINUE TO PUSH INTO
EASTERN NORTH CAROLINA AS A WARM FRONT LIFTS TO THE NORTH THIS
MORNING. PER LATEST 4 KM WRF AND RAP MODELS...LIGHT RAIN SHOULD
BECOME WIDESPREAD BY AROUND 12Z. AS A COLD FRONT THEN MOVES ACROSS
THE AREA...RAIN WILL PERSIST INTO THE EVENING BEFORE THE FRONT
SHIFTS OFFSHORE. A STRONG LLJ WILL DEVELOP...SO EXPECT GUSTY WINDS
TO INCREASE MONDAY MORNING THROUGH THE AFTERNOON. CROSSWINDS WILL
BE AN ISSUE FOR SITES USING A E-W OR NW-SE ORIENTED RUNWAY. RAINS
WILL CONTINUE ALL DAY WITH CEILINGS FLIRTING NEAR OR JUST BELOW
IFR.
LONG TERM /MONDAY NIGHT THROUGH THURSDAY/...
AS OF 330 PM SUN...COULD BE SOME LINGERING SHOWERS MAINLY AT KEWN
AND KOAJ MON NIGHT BEFORE HIGH PRES MOVES IN LATE NIGHT INTO
TUESDAY. MORE RAIN MOVES IN LATE TUE NIGHT AND LINGERS THROUGH WED.
THERE COULD BE SUB VFR CIGS WITH THE SHOWERS. HIGH PRES BUILDS FOR
THUR AND FRI.
&&
.MARINE...
SHORT TERM /THROUGH MONDAY/...
AS OF 1245 AM MONDAY...LIGHT ESE/SE WINDS WILL BECOME MORE
SOUTHERLY AND INCREASE OVER THE NEXT FEW HOURS AS A WARM FRONT
LIFTS NORTH OF THE REGION. SMALL CRAFT CONDITIONS SHOULD DEVELOP
TOWARD MORNING AS LATEST 10M WIND FORECASTS FOR THE HIGH-RES WRF
AND RAP MODELS INDICATE WIDESPREAD 20 TO 25 KNOT WINDS BY 10Z OR
SO. SEAS WILL BUILD TO 6 TO 9 FT IN RESPONSE TO THE INCREASED
FLOW. SOUTHERLY WINDS AHEAD OF THE APPROACHING COLD FRONT WILL
INCREASE WINDS TO 25 TO 30 KNOTS WITH SEAS BUILDING 7-10 FT LATER
TODAY. NO CHANGES TO THE CURRENT SCA HEADLINES BEGINNING
OVERNIGHT.
BLEND OF WW3...NWPS AND PREVIOUS FCST USED FOR SEAS.
LONG TERM /MONDAY NIGHT THROUGH FRIDAY/...
AS OF 330 PM SUN...SW WINDS WILL SLOWLY DIMINISH THROUGH MON EVENING
THOUGH SEAS WILL REMAIN 6 FEET OR HIGHER THROUGH THE OVERNIGHT. HIGH
PRES BUILDS IN FOR TUE BRINGING GOOD BOATING CONDITIONS. WEAK LOW
PRES WILL DEVELOP DURING THE DAY WEDNESDAY ACROSS THE SOUTHERN NC
COASTAL WATERS. THIS WILL BRING EASTERLY WINDS TO START ACROSS THE
AREA. CONDITIONS LOOK TO REMAIN SUB SCA HOWEVER ON WED. DURING
THE AFTERNOON AS THE LOW PULLS EASTWARD WINDS WILL SWITCH TO THE
WEST AND THEN NORTHWEST BY EVENING. COULD BE A BRIEF PD WHERE
WINDS NEAR 25 KT AND WAVES OF 6 FT OR HIGHER WED NIGHT INTO EARLY
THUR. HIGH PRESSURE WILL BE IN CONTROL FOR THE REMAINDER OF THE
WEEK BRINGING GOOD BOATING CONDITIONS. A STRONG COLD FRONT LOOKS
TO MOVE THROUGH THE SECOND HALF OF THE WEEKEND BRINGING THE
POTENTIAL FOR SCA WINDS/SEAS ON STRONG NW WINDS.
&&
.MHX WATCHES/WARNINGS/ADVISORIES...
NC...NONE.
MARINE...SMALL CRAFT ADVISORY FROM 7 AM THIS MORNING TO 10 PM EST THIS
EVENING FOR AMZ135.
SMALL CRAFT ADVISORY FROM 7 AM THIS MORNING TO 7 PM EST THIS
EVENING FOR AMZ130.
SMALL CRAFT ADVISORY UNTIL 10 AM EST TUESDAY FOR AMZ152-154.
SMALL CRAFT ADVISORY UNTIL 7 AM EST TUESDAY FOR AMZ156-158.
SMALL CRAFT ADVISORY FROM 4 AM EARLY THIS MORNING TO 4 AM EST
TUESDAY FOR AMZ150.
&&
$$
SYNOPSIS...JBM
NEAR TERM...CTC
SHORT TERM...JBM
LONG TERM...TL
AVIATION...RSB/CTC/TL
MARINE...RSB/CTC/TL
AREA FORECAST DISCUSSION
NWS WILMINGTON NC
1240 AM EST MON FEB 11 2013
.SYNOPSIS...
A WARM FRONT WILL LIFT NORTH ACROSS THE AREA OVERNIGHT. RAIN IS
EXPECTED TONIGHT INTO MONDAY AHEAD OF A PRE-FRONTAL TROUGH. A COLD
FRONT WILL MOVE ACROSS THE AREA EARLY ON TUESDAY...BEFORE
STALLING. A DEEPENING LOW PRESSURE SYSTEM WILL MOVE ACROSS THE
AREA ON WEDNESDAY...WITH HIGH PRESSURE RETURNING FOR THE END OF
THE WEEK. AN ARCTIC BLAST MAY REACH THE EASTERN CAROLINAS IN THE
WAKE OF A COLD FRONT NEXT WEEKEND.
&&
.NEAR TERM /UNTIL 6 AM THIS MORNING/...
AS OF 12:40 AM MONDAY...LIGHT RAIN HAS PROGRESSED EASTWARD ACROSS
ALL BUT THE COASTAL COUNTIES. NO CHANGES TO THE FORECAST WITH THE
LATEST UPDATE. LOOKS LIKE VIRTUALLY ALL AREAS...EXCEPT POSSIBLY
FOR SPOTS IN GEORGETOWN COUNTY...WILL SEE RAIN OVERNIGHT. PREVIOUS
DISCUSSIONS FOLLOW BELOW:
THE FORECAST REMAINS ESSENTIALLY ON-TRACK THIS EVENING. REGIONAL
RADAR COMPOSITES SHOW ECHOES NOT QUITE TO I-95...AND SURFACE OBS
SHOW PRECIP IS REACHING THE GROUND UNDER ALL BUT THE 15 DBZ AND
LOWER RADAR REFLECTIVITIES. THE LATEST SEVERAL RUNS OF THE RUC AND
HRRR MODELS SUGGEST A LIGHTER-QPF EVENT THAN WAS INITIALLY
THOUGHT...AND WITH A SOUTHWARD SHIFT IN THE LOCATION OF HEAVIEST
RAINFALL IN THE 3-6 A.M. TIME FRAME. SINCE THIS IDEA APPEARS TO BE
SUPPORTED BY LIGHT RADAR ECHOES OBSERVED AS FAR SOUTH AS AUGUSTA
GA...I HAVE INCREASED POPS FOR THE SOUTHERN END OF THE SC PEE DEE
REGION AND DOWN TO THE COAST BY 10-20 PERCENT...ALTHOUGH WITH NO
ATTENDANT INCREASE IN FORECAST RAINFALL AMOUNTS.
THE SYNOPTIC PATTERN HAS A WARM FRONT EXTENDING FROM JUST SOUTH OF
CAPE LOOKOUT TO NEAR CAROLINA BEACH...THEN SOUTH-SOUTHWESTWARD JUST
OFFSHORE FROM MYRTLE BEACH AND GEORGETOWN. IN RESPONSE TO
STRENGTHENING SOUTH FLOW THE FRONT IS LIFTING NORTHWARD AT AN
INCREASING RATE AND MAY "JUMP" NORTH THROUGH MY ENTIRE FORECAST AREA
IN THE NEXT COUPLE OF HOURS. EASTERLY SURFACE WINDS WILL VEER
SOUTHERLY AND INCREASE TO 10-15 MPH...WITH 20-25 MPH GUSTS POSSIBLE
AFTER MIDNIGHT.
A HEALTHY UPPER TROUGH EXTENDS SOUTHWARD FROM AN UPPER LOW IN
SOUTHERN MINNESOTA. PLENTY OF GULF MOISTURE ADVECTED NORTH AHEAD OF
THIS TROUGH IS PRODUCING SEVERE WEATHER AND HEAVY RAINFALL ACROSS
THE DEEP SOUTH. ALTHOUGH THE AIRMASS OVER THE EASTERN CAROLINAS
SHOULD REMAIN TOO STABLE FOR CONVECTION...THIS SAME MOISTURE FEED IS
WHAT WILL CREATE OUR RAINFALL CHANCES TONIGHT. BY DAYBREAK RAINFALL
AMOUNTS AROUND A HALF INCH ARE EXPECTED ACROSS DARLINGTON COUNTY...
TAPERING DOWN TO AROUND A THIRD OF AN INCH FROM LUMBERTON INTO
MARION AND FLORENCE. CLOSER TO THE COAST AND SOUTH TOWARD THE SANTEE
RIVER RAINFALL AMOUNTS OF ONE OR TWO-TENTHS OF AN INCH ARE EXPECTED
BY DAYBREAK.
WE ARE AT OUR LOW TEMPERATURES CURRENTLY...AND READINGS SHOULD RISE
BY 3-5 DEGREES OVER THE NEXT SEVERAL HOURS AS WARMER AIR FROM
GEORGIA AND OFFSHORE SOUTH CAROLINA ADVECTS OVERHEAD.
&&
.SHORT TERM /6 AM THIS MORNING THROUGH TUESDAY NIGHT/...
AS OF 3 PM SUNDAY...COMPLICATED AND CHALLENGING FORECAST PERIOD.
FORECAST AREA WILL BE IN THE WARM SECTOR AHEAD OF PRE-FRONTAL TROUGH
ON MON. EVEN WITH AN ABUNDANCE OF CLOUD COVER...CAPE VALUES MAY
STILL REACH UP TO 500 J/KG MON AFTERNOON. DEEP MOISTURE WILL BE IN
PLACE...WITH PRECIPITABLE WATER VALUES NEAR 1.5 INCHES. THE HIGHEST
INSTABILITY WILL BE ACROSS THE SOUTHERN AND EASTERN ZONES...THUS
ADDED ISOLATED THUNDERSTORMS TO THE FORECAST FOR MON AFTERNOON.
GIVEN THE MAGNITUDE OF LIFT...HIGHLY CONFIDENT THERE WILL BE SHOWERS
AND WILL CARRY CATEGORICAL POPS MON. AS THE PRESSURE GRADIENT
TIGHTENS ON MON...SW LOW LEVEL JET WILL INCREASE TO 40 TO 50 KT AND
EXPECT SOME WIND GUSTS ON MON TO AROUND 30 MPH. ONCE THE PRE-FRONTAL
TROUGH MOVES THROUGH MON AFTERNOON/EARLY EVE...LASTLY ALONG THE
COAST...DRIER AIR IN THE LOW AND MID LEVELS WILL WORK INTO THE
FORECAST AREA. THIS DRIER AIR SHOULD LARGELY CUT OFF THE RISK FOR
PRECIPITATION...BUT GIVEN THE ACTUAL FRONT WILL NOT LIMP INTO THE
FORECAST AREA TIL TUE MORNING...WILL CARRY SMALL POPS FOR PORTIONS
OF THE AREA EVEN AFTER DARK MON.
ATTENTION THEN TURNS TO A SOUTHERN STREAM SYSTEM WHICH WILL BE
DEVELOPING ALONG THE GULF COAST IN RESPONSE TO A HIGHLY ENERGIZED
MID-LEVEL SHORTWAVE MOVING ACROSS THE SOUTHERN PLAINS TUE. THE
EUROPEAN MODEL HAS BEEN THE MOST CONSISTENT AND CONTINUES TO
INDICATE SURFACE LOW PRESSURE MOVING ALONG A STALLED FRONT AND
REACHING THE SE STATES TUE NIGHT...BEFORE TRANSFERRING TO THE
CAROLINA COAST DURING WED. STILL SOME DISCREPANCY AS TO HOW FAR N
THE STRONGEST ISENTROPIC UPGLIDE WILL DEVELOP AND THUS WHERE THE
HEAVIEST RAIN WILL DEVELOP. CONFIDENT THAT POPS...WHICH HAD BEEN
TRENDED LOWER MON NIGHT INTO TUE...WILL BEGIN TO REVERSE HIGHER...
FROM S TO N...TUE AFTERNOON AND ESPECIALLY TUE NIGHT. WILL BRING
POPS BACK TO CATEGORICAL OVERNIGHT TUE INTO WED MORNING. THE
CHARACTER OF PRECIPITATION THIS TIME AROUND SHOULD BE STRATIFORM AS
LONG AS THE MORE SOUTHERN TRACK VERIFIES AND WILL NOT ADD
THUNDERSTORMS TO THE TUE FORECAST AT THIS TIME.
CONFIDENCE IN THE QPF FORECAST HAS NOT INCREASED...BUT AT THIS TIME
WE ARE FORECASTING A 1 TO POSSIBLY 3 INCH RAINFALL EVENT THROUGH MID
WEEK. THIS AMOUNT OF RAIN SHOULD NOT BE ENOUGH TO CAUSE FLOODING
ALTHOUGH RIVERS WILL LIKELY BE ON THE RISE MID AND LATE WEEK. SHOULD
SIGNIFICANTLY HIGHER RAINFALL AMOUNTS MATERIALIZE...THE RISK FOR
SOME FLOODING WOULD INCREASE. LATER FORECASTS WILL STRIVE TO BETTER
DEFINE THE TOTAL AMOUNT OF RAINFALL AND ANY FLOOD RISK.
&&
.LONG TERM /WEDNESDAY THROUGH SUNDAY/...
AS OF 3 PM SUNDAY...MAIN FOCUS WILL BE ON THE EARLY PART OF THE
FORECAST WHERE POPS REMAIN A DILEMMA AND THE END OF THE PERIOD WHERE
ARCTIC AIR WILL BE AN ISSUE.
FOR WEDNESDAY...THERE REMAINS A DIFFERENCE IN MEDIUM RANGE GUIDANCE
AS THE ECMWF IS LESS AMPLIFIED AND HENCE MORE PROGRESSIVE WITH THE
MAIN UPPER LEVEL FEATURE MOVING ACROSS THE TENNESSEE VALLEY. THE GFS
REMAINS CONSISTENT WITH A SLOWER AND DEEPER SOLUTION. I HAVE
MAINTAINED THE INHERITED CATEGORICAL POPS BASED PRIMARILY ON
CONTINUITY OF THE GFS ALTHOUGH IT SHOULD BE NOTED CONFIDENCE EVEN
JUST A FEW DAYS OUT REMAINS UNUSUALLY LOW.
FOR THURSDAY THROUGH SATURDAY...A BROAD EASTERN U.S. TROUGH DEVELOPS
WITH SURFACE HIGH PRESSURE CENTERED ACROSS THE SOUTHERN U.S. EXPECT
TEMPERATURES AT OR JUST BELOW CLIMATOLOGY ALONG WITH DRY CONDITIONS.
AS THE EASTERN PACIFIC RIDGE DEVELOPS THROUGH THE PERIOD... SEVERAL
SHORTWAVES WILL DIVE SOUTH AND REINFORCE THE BROAD TROUGH THUS
RELEASING A SHOT OF ARCTIC AIR.
THE 0600 OPERATIONAL GFS WAS ADVERTISING 850MB TEMPERATURES AS COLD
AS MINUS 15 DEGREES C MOVING ACROSS THE AREA BRIEFLY NEXT SUNDAY.
HOWEVER THE 1200 UTC GUIDANCE HAS MODERATED SOMEWHAT AND THESE
NUMBERS APPEAR MORE REASONABLE. ACTUAL LOWS WILL BE MODULATED BY
DECOUPLING OR LACK THEREOF. IT HAS ALSO BEEN MY EXPERIENCE IN THE
PAST THAT ARCTIC AIR OUTBREAKS LATER IN THE SEASON WITH THE HIGHER
SUN ANGLES MAKE MEX NUMBERS MORE ACCURATE.
&&
.AVIATION /06Z MONDAY THROUGH FRIDAY/...
AS OF 06Z...CURRENTLY VFR AT ALL TERMINALS. A LARGE AREA OF RAIN
IS MOVING ACROSS THE KFLO/KLBT TERMINALS TOWARDS THE COASTAL TERMINALS.
CONFIDENCE IS HIGH THAT FLIGHT CONDITIONS WILL DETERIORATE TO MVFR
DUE TO MAINLY REDUCED VSBYS IN RAIN AND BR AT KFLO/KLBT EARLY THIS
MORNING. THE HEAVIEST OF THE RAIN SHOULD OCCUR 08Z-14Z AND IT IS
DURING THIS TIME THAT THE GREATEST THREAT OF IFR WILL OCCUR. MOST OF
THE RAIN SHOULD END BY 14Z BUT THERE WILL REMAIN A GOOD CHANCE OF
MVFR CONDITIONS/SHOWERS THROUGH 19Z AND MVFR CIGS THROUGH 22Z.
THERE IS HIGH CONFIDENCE OF MVFR CONDITIONS DEVELOPING AT THE
COASTAL TERMINALS BY 08-09Z. THE HEAVIEST OF RAIN SHOULD OCCUR IN
THE 12Z-17Z TIME FRAME. IT IS DURING THIS TIME THE GREATEST THREAT
OF IFR WILL OCCUR. THERE MAY BE A TEMPO LULL IN PRECIPITATION
INTENSITY BY 16-17Z...BUT THERE WILL REMAIN A GOOD CHANCE OF TEMPO
IFR/SHOWERS THROUGH 20-21Z...AND MVFR CIGS THROUGH THE EVENING.
EXTENDED OUTLOOK...RAIN LIKELY WITH PERIODS OF MVFR/IFR CONDITIONS
THROUGH WEDNESDAY. VFR DEVELOPING THURSDAY AND PERSISTING THROUGH
FRIDAY.
&&
.MARINE...
NEAR TERM /THROUGH TONIGHT/...
AS OF 12:40 AM MONDAY...NO CHANGES TO THE FORECAST WITH THE LATEST
UPDATE. SMALL CRAFT ADVISORY REMAINS IN EFFECT. LATEST OBS SHOW 3
TO 5 FT SEAS BUT WINDS ARE STILL ON THE INCREASE. PREVIOUS
DISCUSSION FOLLOWS BELOW:
THE WARM FRONT IS FINALLY BEGINNING TO MAKE A MOVE TO THE
NORTH...CURRENTLY EXTENDING FROM JUST SOUTH OF CAPE LOOKOUT TO
NEAR CAROLINA BEACH...THEN SOUTH-SOUTHWESTWARD THROUGH THE SOUTH
CAROLINA COASTAL WATERS REMAINING JUST EAST OF GEORGETOWN. ON THE
COOL SIDE OF THIS BOUNDARY SURFACE WINDS REMAIN EASTERLY. THE
SOUTHERLY WINDS OVER THE FRONT ARE ERODING THE COOLER SURFACE AIR
RATHER QUICKLY...AND THE FRONT SHOULD "JUMP" NORTH ACROSS MY
FORECAST AREA IN THE NEXT SEVERAL HOURS...WITH SOUTHERLY WINDS AT
THE SURFACE THE ANTICIPATED RESULT. WIND SPEEDS SHOULD INCREASE TO
20-25 KT...BUT WITHOUT ANY SUBSTANTIAL GUSTINESS GIVEN VERY STABLE
THERMODYNAMIC PROFILES. SEAS CURRENTLY 3-4 FT WILL BEGIN TO BUILD
SUBSTANTIALLY AFTER MIDNIGHT AND COULD REACH 8 FEET ACROSS THE
OUTER PORTION OF THE COASTAL WATERS BY DAYBREAK MONDAY.
SHORT TERM /MONDAY THROUGH TUESDAY NIGHT/...
AS OF 3 PM SUNDAY...A MOIST AND INCREASING SOUTHERLY FLOW WILL
DEVELOP AHEAD OF A PRE-FRONTAL TROUGH. SMALL CRAFT ADVISORY
CONDITIONS ARE EXPECTED TO HAVE ALREADY BEGUN BY THE START OF THE
PERIOD AND TO CONTINUE INTO MON NIGHT...SSW TO SW WINDS TO 20 TO 25
KT WITH SEAS PEAKING IN THE 6 TO 10 FT RANGE...HIGHEST ACROSS THE
OUTER NORTHERN WATERS. DECREASING WINDS WILL VEER TO W BEHIND THE
PRE-FRONTAL TROUGH MON EVE AND THEN BECOME NW BEHIND A COLD FRONT
TUE MORNING. WINDS AND SEAS ARE EXPECTED TO FALL BELOW ADVISORY
CRITERIA LATE MON NIGHT. SINCE DEWPOINTS WILL BE CLIMBING INTO THE
LOWER 60S...THERE IS SOME RISK FOR THE DEVELOPMENT OF SEA FOG ON
MON. AT THIS TIME...GIVEN THE MAGNITUDE OF WIND...WILL OPT FOR
STRATUS OVER FOG AND WILL LEAVE OUT OF THE FORECAST. AS LOW PRESSURE
APPROACHES FROM THE W AND SW TUE NIGHT...WINDS WILL SHIFT TO THE NE
AND THEN ENE...INCREASING WITH THE APPROACH OF DAYBREAK WED.
LONG TERM /WEDNESDAY THROUGH FRIDAY/...
AS OF 3 PM SUNDAY...CHANGEABLE CONDITIONS AT LEAST THROUGH THE EARLY
PART OF THE PERIOD...WILL BE THE HIGHLIGHT OF THE FORECAST.
EASTERLY FLOW INITIALLY WILL QUICKLY GIVE WAY TO A SOUTHERLY FLOW BY
MIDDAY WEDNESDAY AS A WARM FRONT MOVES ACROSS TO THE NORTH. WINDS
THEN QUICKLY VEER TO WEST NORTHWEST BY EARLY THURSDAY AS A COLD
FRONT MOVES ACROSS. BY FRIDAY WINDS ESSENTIALLY BECOME LIGHT AND
VARIABLE AS HIGH PRESSURE DRIFTS OVERHEAD.
FOR SEAS...SOME RESIDUAL SIX FOOTERS MAY WARRANT AN ADVISORY FOR
PART OR MOST OF WEDNESDAY ESPECIALLY ACROSS THE OUTER WATERS BUT
LATER THURSDAY AND FRIDAY OFFER MORE BENIGN VALUES WITH THE
DIMINISHING OFFSHORE FLOW.
&&
.ILM WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
NC...NONE.
MARINE...SMALL CRAFT ADVISORY UNTIL 1 AM EST TUESDAY FOR AMZ250-252-254-
256.
&&
$$
NEAR TERM...REK/JDW
SHORT TERM...RJD
LONG TERM...SHK
AVIATION...MRR
MARINE...REK/RJD/JDW/SHK
AREA FORECAST DISCUSSION
NWS BISMARCK ND
1214 AM CST MON FEB 11 2013
.DISCUSSION...LATEST WATER VAPOR IMAGERY SHOWS THE UPPER LOW
CIRCULATION ALONG THE CENTRAL MINNESOTA/WISCONSIN BORDER WITH A
TROWAL EXTENDING INTO FAR EASTERN NORTH DAKOTA. THIS WOULD RESULT
IN THE SNOW TO CONTINUE TAPERING OFF IN THE JAMES RIVER VALLEY
THROUGH 12Z.
COLLABORATED WITH NEIGHBORING OFFICES AND WILL CONTINUE WITH THE
CURRENT HEADLINES. VISIBILITIES AROUND ONE MILE IN THE BLIZZARD
WARNING BUT IN BETWEEN REPORTING STATIONS AND IN THE OPEN COUNTRY
VISIBILITIES COULD POSSIBLY BE LOWER AS WINDS CONTINUE TO GUST
NEAR 40 MPH.
THE FOG/STRATUS LOOP SHOWS PLENTY OF CLOUD COVER EXTENDING INTO
CENTRAL MONTANA AND INTO SASKATCHEWAN AND MANITOBA. LATEST RAP AND
NAM 925MB RH FIELD KEEPS THE STRATUS THROUGH 18Z BEFORE ERODING IT
ALONG THE EDGES LATER MONDAY AFTERNOON.
&&
.AVIATION...IFR/MVFR CONDITIONS WILL PERSIST AT ALL AERODROMES
THROUGH AT LEAST 18Z MONDAY...WITH IMPROVEMENTS TO VFR AT KISN AND
KDIK BETWEEN 18Z AND 21Z MONDAY. BLOWING SNOW WILL CONTINUE AT KJMS
THROUGH 15Z MONDAY RESULTING IN IFR TO LIFR VSBYS.
&&
.BIS WATCHES/WARNINGS/ADVISORIES...
BLIZZARD WARNING UNTIL 6 AM CST MONDAY FOR NDZ037-047-048-050-
051.
WINTER WEATHER ADVISORY UNTIL 6 AM CST MONDAY FOR NDZ025-036-046.
&&
$$
DISUCSSION...KS
AVIATION...RK/KS
AREA FORECAST DISCUSSION
NWS WILMINGTON OH
1238 AM EST MON FEB 11 2013
.SYNOPSIS...
A LOW PRESSURE SYSTEM WILL MOVE THROUGH THE AREA TONIGHT. HIGH
PRESSURE WILL BUILD INTO THE AREA ON MONDAY AND REMAIN ACROSS THE
REGION FOR TUESDAY. A STORM SYSTEM WILL MOVE SOUTH OF THE AREA ON
WEDNESDAY BRINGING A CHANCE FOR PRECIPITATION TO SOUTHERN PORTIONS
OF THE REGION.
&&
.NEAR TERM /UNTIL 6 AM THIS MORNING/...
MAIN AREA OF PCPN IS EXITING OUR EASTERN AREAS SO WILL TRIM BACK
POPS ACROSS THE EAST IN THE SHORT TERM. PCPN IS TRYING TO FILL IN
ACROSS INDIANA AS SUGGESTED BY THE NAM AND HRRR BUT SO FAR IT
STILL APPEARS TO BE PRETTY LIGHT. WILL ALLOW FOR CHANCE POPS
ASSOCIATED WITH THIS TO SPREAD BACK EAST ACROSS OUR AREA THROUGH
THE LATE EVENING AND ON INTO THE EARLY MORNING HOURS BUT EXPECT
ANY MEASURABLE PCPN TO BE ON THE LIGHT SIDE.
&&
.SHORT TERM /6 AM THIS MORNING THROUGH TUESDAY NIGHT/...
HIGH PRESSURE WILL BEGIN TO WORK INTO THE FA ON MONDAY. THERE
WILL BE A BREAK IN THE CLOUDS DURING THE MORNING HOURS ACROSS THE
FA. IT IS DURING THIS TIME THAT WINDS WILL INCREASE ACROSS THE FA
AND EXPECT THE HIGHEST WINDS ACROSS THE FA DURING THE LATE MORNING
TO EARLY AFTERNOON TIME FRAME. SUSTAINED WINDS WILL BE AROUND 20
TO 25 MILES PER HOUR WITH WIND GUSTS AROUND 35 TO 45 MILES PER
HOUR. THESE WINDS FALL SLIGHTLY BELOW WIND ADVISORY CRITERIA AND
THEREFORE DECIDED NOT TO ISSUE A WIND ADVISORY FOR MONDAY. WILL
CONTINUE TO HIGHLIGHT THE WINDS IN THE HWO. ADDITIONAL CLOUDS WILL
WORK INTO THE AREA FOR THE AFTERNOON HOURS. GUSTY WINDS WILL
REMAIN ACROSS THE FA THROUGH THE AFTERNOON AND EVENING HOURS. WINDS
WILL DECREASE ACROSS THE AREA MONDAY NIGHT.
TEMPERATURES ON MONDAY WILL NOT RISE MUCH FROM SUNDAY NIGHT LOWS.
EXPECT HIGH TEMPERATURES ON MONDAY TO BE IN THE LOW TO UPPER 40S.
WITH CLOUD COVER DECREASING ACROSS THE FA MONDAY NIGHT
TEMPERATURES WILL DROP DOWN INTO THE 20S ACROSS MOST LOCATIONS.
HIGH PRESSURE WILL KEEP DRY CONDITIONS ACROSS THE FA TUESDAY AND
INTO TUESDAY NIGHT.
&&
.LONG TERM /WEDNESDAY THROUGH SUNDAY/...
LOW PRESSURE WILL PASS SOUTH OF THE REGION ON WEDNESDAY. STILL SOME
MODEL DISAGREEMENT ON HOW FAR NORTH THE PRECIPITATION SHIELD WILL
SPREAD. HAVE LIMITED POPS TO THE FAR SOUTH/SOUTHEASTERN COUNTIES.
LOOKS LIKE THIS WOULD BE A MIX OF LIGHT SNOW AND RAIN. ONCE THIS
SYSTEM MOVES OFF THERE WILL BE A BRIEF PERIOD OF RIDGING ON
THURSDAY. BUT THEN LOW PRESSURE WILL TRACK ACROSS THE GREAT LAKES ON
FRIDAY WHICH WILL SWING A COLD FRONT THROUGH THE REGION. COLD
NORTHWEST FLOW WILL THEN PREVAIL THROUGH THE WEEKEND. COULD SEE SOME
SNOW SHOWERS OR FLURRIES WITH THE FRONT AND INTO THE WEEKEND. BUT
NARROWING DOWN A MORE FAVORABLE PERIOD FOR MEASURABLE PRECIPITATION
IS PROBLEMATIC THIS FAR OUT IN TIME. SO KEPT POPS MAINLY IN SLIGHT
CHANCE CATEGORY.
&&
.AVIATION /06Z MONDAY THROUGH FRIDAY/...
MVFR CEILINGS LINGER IN A MOIST SOUTHERLY FLOW ALONG AND AHEAD OF
A COLD FRONT. SHOWERS HAVE JUST ABOUT ENDED THOUGH SOME LIGHT RAIN
MAY PERSIST AT CMH AND LCK. CONDITIONS WILL IMPROVE TO VFR BY MID
MORNING AS THE FRONT PROGRESSES EAST AND DRIER AIR WORKS IN.
WINDS WILL BE A PROBLEM WITH GUSTS OVER 30 KNOTS OUT OF THE
SOUTHWEST EXPECTED IN A TIGHT PRESSURE GRADIENT BEHIND THE FRONT.
WINDS WILL SUBSIDE TO AROUND 12 KNOTS ABOUT 00Z AS DIRECTION
SHIFTS TO WEST.
OUTLOOK...NO SIGNIFICANT WEATHER IS EXPECTED.
&&
.ILN WATCHES/WARNINGS/ADVISORIES...
OH...NONE.
KY...NONE.
IN...NONE.
&&
$$
SYNOPSIS...NOVAK
NEAR TERM...JGL
SHORT TERM...NOVAK
LONG TERM...
AVIATION...CONIGLIO
AREA FORECAST DISCUSSION
NWS CLEVELAND OH
1147 PM EST SUN FEB 10 2013
.SYNOPSIS...
LOW PRESSURE TRACKING OUT OF THE PLAINS WILL MOVE THROUGH THE UPPER
GREAT LAKES ON MONDAY...PULLING AWAY TO THE NORTHEAST ON TUESDAY. A
RIDGE WILL EXPAND NORTH ACROSS THE OHIO VALLEY ON TUESDAY AND LINGER
INTO WEDNESDAY. A CLIPPER WILL APPROACH THE REGION FROM THE
NORTHWEST ON THURSDAY.
&&
.NEAR TERM /UNTIL 6 AM MONDAY MORNING/...
THE FRONT WILL MOVE ACROSS THE AREA LATE TONIGHT AND MONDAY
MORNING. THE FIRST BATCH OF SHOWERS HAVE DECREASED...SOME
SPRINKLES COULD BE OCCURRING OVER NW PA THROUGH MIDNIGHT. THE DEW
POINTS ARE LOW OVER NW PA BUT THE TEMPERATURES ARE WARM ENOUGH AND
WILL CONTINUE TO RISE AS WILL THE DEW POINTS. THE THREAT OF THE
TEMPERATURE DROPPING TO 32F IS NEGLIGIBLE. ALSO THE ROAD
TEMPERATURES ARE NEAR 40F...SO THAT WILL ALSO HELP PREVENT ANY ICY
ROADS.
THE NEXT BATCH OF SHOWERS WERE TRYING TO DEVELOP OVER WESTERN
OHIO. THE HRRR MODEL IS HINTING AT IT...MORE OF A SCATTERED NATURE.
THE 12Z 4KM WRF NMM MODEL IS HINTING AT WIDESPREAD SHOWERS
DEVELOPING AFTER MIDNIGHT. THAT IS POSSIBLE WITH ENOUGH
MOISTURE...PLENTY OF OMEGA AND SOME LOW LEVEL AND UPPER JET
HELP...LEFT FRONT QUAD OF THE JET. KEPT THE POPS LIKELY FOR THE
OVERNIGHT. CONFIDENCE IS LOW TO MODERATE.
RAINFALL AMOUNTS WILL BE UNDER TWO TENTHS OF AN INCH. ADJUSTED
SOME OF THE LOWS BASED ON A SLOWER TIMING OF THE FRONT.
ALSO REMOVED THE MENTION OF THUNDER AS THE AIRMASS IS TOO STABLE.
&&
.SHORT TERM /6 AM MONDAY MORNING THROUGH WEDNESDAY NIGHT/...
BY MONDAY MORNING THE MID-LEVEL DRY SLOT WILL HAVE SPREAD EAST
ACROSS OUR ENTIRE FORECAST AREA WITH DRY CONDITIONS IN MOST AREAS.
HAVE LOWERED POPS IN THE EAST TO JUST A LOW CHANCE AFTER 12Z. THE
COLD FRONT WILL MOVE INTO NW OHIO TOWARDS 14Z...CLEARING NW PA
DURING THE EARLY AFTERNOON. LOW LEVEL WRAP AROUND MOISTURE WILL
INCREASE WITH THE FRONT WITH FAIRLY STEEP LOW LEVEL LAPSE RATES AND
ONLY A SLIGHT CHANCE OF RAIN...EVENTUALLY COOLING ENOUGH FOR
FLURRIES OR A STRAY SNOW SHOWER LATE. HAVE ISSUED A WIND ADVISORY
FOR THE WESTERN HALF OF THE AREA AND LAKESHORE COUNTIES WITH BOTH
THE NAM/GFS ADVERTISING A MIXED LAYER TO NEARLY 850MB WHERE WINDS
INCREASE TO 50 KNOTS. WITH LITTLE IN THE WAY OF DOWNWARD MOMENTUM
WILL HAVE TO RELY ON THE TIGHT PRESSURE GRADIENT AND MECHANICAL
MIXING TO SEE THE STRONGER WINDS MATERIALIZE AT THE SURFACE. STILL
EXPECTING TO SEE SOUTHWEST WINDS OF 20-30 MPH WITH GUSTS NEAR 50
MPH.
TEMPERATURES BEHIND THE LAKE WILL BE MARGINAL FOR LAKE EFFECT BUT
ENOUGH CONVERGENCE ALONG THE SHORELINE SHOULD BE ENOUGH FOR
LINGERING SNOW SHOWERS EXTREME NE OHIO/NW PA. NOT EXPECTING MUCH IN
THE WAY OF ACCUMULATION.
A RIDGE WILL EXPAND NORTH OVER THE AREA THROUGH TUESDAY WITH SNOW
SHOWERS ENDING BY TUESDAY NIGHT. A SHORTWAVE DROPS THROUGH THE
NORTHWEST FLOW ON TUESDAY AND HELPS TO RE-ENFORCE THE TROUGH OVER
THE GREAT LAKES. THIS SHOULD HELP TO KEEP LOW PRESSURE SYSTEM EAST
OF THE APPALACHIANS ON WEDNESDAY.
&&
.LONG TERM /THURSDAY THROUGH SUNDAY/...
THE MODELS HAVE BEEN PRETTY CONSISTENT DEEPENING THE TROUGH ALOFT
LATE IN THE WEEK. THE FIRST IN A SERIES OF COLD FRONTS SEEMS TO
CROSS THE AREA LATE THURSDAY. NOT MUCH MOISTURE AVAILABLE AND THE
FRONT IS WEAK AND WILL HAVE JUST A SLIGHT CHANCE OF SHOWERS THURSDAY
AFTERNOON...WITH A CHANCE OF SOME SNOW SHOWERS DEVELOPING THURSDAY
NIGHT.
APPEARS AS THOUGH A REINFORCING PUNCH OF COLDER AIR WILL ARRIVE
FRIDAY AND WILL HAVE A CHANCE OF SNOW SHOWERS FOR THE ENTIRE
FORECAST AREA ALTHOUGH AS WE GET CLOSER WE WILL PROBABLY NEED
"LIKELY" POPS...PROBABLY AT LEAST FOR NE OH/NW PA. A LITTLE NERVOUS
WITH SUCH A DEEP TROUGH PROGGED BY THE WEEKEND THAT SOME
CYCLOGENESIS COULD OCCUR BUT PERHAPS IT IS ALL TO THE EAST NEAR THE
COAST? IN ANY CASE...WE WILL CONTINUE TO SEE SNOW FLURRIES AND LAKE
EFFECT SNOW SHOWERS THIS WEEKEND. NUDGED TEMPERATURES DOWN A COUPLE
OF CATEGORIES BY THE WEEKEND WITH HIGHS IN THE 20S AND LOWS MOSTLY
IN THE TEENS. WE CAN REFINE THE FORECAST AS WE GET CLOSER.
&&
.AVIATION /06Z MONDAY THROUGH FRIDAY/...
ACTIVE CONVECTION ACROSS THE SOUTH CUT OFF THE MOISTURE SOURCE
INTO OUR REGION AND HENCE CUT WAY BACK ON THE PRECIPITATION
AMOUNTS. VIRTUALLY REMOVED THREAT FOR PRECIPITATION AT ALL AREAS
EXCEPT FOR ERIE. CEILINGS AND VISIBILITIES WILL DROP INTO MVFR
CATEGORY OVERNIGHT WITH SOME IMPROVEMENT DURING THE DAY ON MONDAY.
WINDS ARE GOING TO BE THE PROBLEM OVERNIGHT INTO TOMORROW AS THEY
BECOME QUITE GUSTY FROM THE SOUTH TO SOUTHWEST. OTHER PROBLEM WILL
BE WIND SHEAR POTENTIAL AT ALL SITES EXCEPT ERIE. EXPECTING
SURFACE WINDS TO BE RELATIVELY LIGHT BUT THEN INCREASE IN SPEED
DRAMATICALLY TO AROUND 50 KNOTS JUST ABOVE THE SURFACE.
THEREFORE...WILL KEEP MENTION OF WIND SHEAR OVERNIGHT.
SURFACE TROUGH MOVES THROUGH THE REGION TOMORROW AND WILL LIKELY
CAUSE CEILINGS AND POSSIBLY VISIBILITIES TO LOWER ONCE AGAIN.
THERE IS THE POSSIBILITY FOR SOME SNOW AGAIN TOMORROW AFTERNOON
WITH THE TROUGH AT ERIE.
OUTLOOK...NON-VFR MONDAY NIGHT AND CONTINUING INTO TUESDAY.
&&
.MARINE...
STRONG LOW PRESSURE WILL TRACK ACROSS THE NORTHERN GREAT LAKES LATER
TONIGHT AND MIDDAY. THE ASSOCIATED COLD FRONT WILL SWING ACROSS LAKE
ERIE MONDAY MORNING. AS THE COLD ADVECTION DEVELOPS THE HIGHER WINDS
WILL MIX DOWN TO THE SURFACE AND GALE FORCE WINDS ARE LIKELY MONDAY
AFTERNOON INTO MONDAY NIGHT. THE ICE ON THE LAKE WILL LIKELY SHIFT
MONDAY INTO TUESDAY.
THE LOW WILL PULL OUT QUICKLY ON TUESDAY AND HIGH PRESSURE WILL
BUILD IN FROM THE WEST AND THE MIDDLE OF THE WEEK SHOULD BE
RELATIVELY QUIET ON THE LAKE. A SERIES OF COLD FRONTS AND CLIPPER
LOW PRESSURE SYSTEMS ARE EXPECTED LATE IN THE WEEK. THE SOUTHWEST
FLOW WILL SHIFT TO NORTHWEST AND WINDS WILL INCREASE LATE IN THE
WEEK... PROBABLY IN THE 15 TO 30 KNOT RANGE.
&&
.CLE WATCHES/WARNINGS/ADVISORIES...
OH...WIND ADVISORY FROM 11 AM MONDAY TO 1 AM EST TUESDAY FOR OHZ011-
012-089.
WIND ADVISORY FROM 9 AM TO 7 PM EST MONDAY FOR OHZ003-006>010-
017>020-027>030-036-037.
PA...WIND ADVISORY FROM 11 AM MONDAY TO 1 AM EST TUESDAY FOR PAZ001.
MARINE...GALE WARNING FROM NOON MONDAY TO 4 AM EST TUESDAY FOR LEZ061-
142>149-162>169.
&&
$$
SYNOPSIS...KEC
NEAR TERM...KIELTYKA
SHORT TERM...KEC
LONG TERM...KOSARIK
AVIATION...LOMBARDY
MARINE...KOSARIK
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
457 PM EST MON FEB 11 2013
.SYNOPSIS...
A COLD FRONT WILL MOVE THROUGH THE AREA EARLY THIS EVENING...FOLLOWED
BY WINDY AND COOLER CONDITIONS TONIGHT INTO TUESDAY. LOW PRESSURE
OVER THE GULF COAST IS EXPECTED TO TRACK NORTHEAST AND OFF THE
DELMARVA PENINSULA LATE WEDNESDAY NIGHT. THIS STORM SYSTEM COULD
BRING A PERIOD OF SNOW TO SOUTHEASTERN AREAS LATE WEDNESDAY AND
WEDNESDAY NIGHT. MAINLY DRY CONDITIONS WITH A BRISK WESTERLY
WIND...AND NEAR TO SLIGHTLY ABOVE NORMAL TEMPERATURES WILL FOLLOW
FOR THURSDAY AND FRIDAY.
&&
.NEAR TERM /UNTIL 6 AM TUESDAY MORNING/...
EARLY EVENING VIS IMAGERY SHOWING LOW CLOUDS REMAIN EAST OF THE
SUSQ VALLEY. LATEST RAP MDL DATA SUGGESTS LITTLE MOVEMENT TO WARM
FRONT BEFORE ARRIVAL OF COLD/OCCLUDED FRONT THIS EVENING.
THE OVERNIGHT WILL FEATURE A PRETTY TYPICAL POST COLD FRONTAL
FLOW PATTERN WITH NORTHWEST FLOW...STRATOCU CEILINGS AND SCATTERED
SNOW SHOWERS OVER THE NORTHWEST AND WEST. EXPECT AN INCH OR TWO OF
NEW SNOW OVER THE USUAL AREAS DOWNWIND FROM THE LAKE AND OVER
UPSLOPE LOCATIONS IN THE LAURELS...BUT LITTLE MORE THAN FLURRIES
ELSEWHERE. THE MAIN THING WILL BE THE INCREASE IN WIND AS THE
COLDER AIR FILTERS IN. THE BEST PRESSURE RISES MOVE NORTH OF THE
STATE...BUT COLD ADVECTION AND SUBSIDENCE MAY BE ENOUGH TO BRING
ABOUT SOME ISOLATED WIND GUSTS IN THE ADVISORY RANGE LATER TONIGHT
INTO TUESDAY MORNING. WILL KEEP THE CURRENT ADVISORY WIND ADVISORY
CONFIGURATION.
OVERNIGHT LOWS WILL AVERAGE WELL ABOVE SEASONAL NORMALS IN THE 20S
TO LOWER 30S.
&&
.SHORT TERM /6 AM TUESDAY MORNING THROUGH 6 PM TUESDAY/...
WINDS WILL GRADUALLY DECREASE THROUGHOUT THE DAY TUESDAY WITH
MOSTLY CLOUDY TO CLOUDY SKIES ACROSS THE CENTRAL AND NRN
ZONES...AND SOME BREAKS OF SUNSHINE OVER THE SOUTHERN TIER OF THE
STATE . SCATTERED MORNING SNOW SHOWERS ACROSS THE NW MTNS WILL
DIMINISH TO JUST SOME AFTERNOON FLURRIES...AS THE SURFACE HIGH
BUILDS ACROSS JUST TO OUR SOUTH BRINGING A LOWER INVERSION HEIGHT
AND ALLOWING CLOUDS TO BECOME SHALLOWER IN THE AFTERNOON.
HIGHS TUESDAY IN THE 30S AND 40S WILL RANGE FROM NEAR NORMAL OVER
THE NORTH TO A BIT ABOVE NORMAL IN THE SOUTH.
&&
.LONG TERM /TUESDAY NIGHT THROUGH MONDAY/...
1016-1018 MB SFC HIGH PRESSURE BUILD NEWD ACROSS THE STATE TUESDAY
NIGHT WITH FAIR SKIES...LIGHT WIND...AND CHILLY TEMPS MAINLY IN THE
20S.
A FAIRLY AMPLIFIED...SPLIT-FLOW UPPER PATTERN IS FORECAST TO PERSIST
THROUGH THE LONG TERM PERIOD ACROSS MUCH OF NORTH AMERICA.
SIGNIFICANT PHASING OF THESE BRANCHES FOR A BRIEF TIME OVER THE
UPCOMING WEEKEND...WILL USHER IN A BLAST OF VERY COLD AIR WITH
TRAJECTORIES RIGHT FROM THE ARCTIC CIRCLE.
THE PRIMARY FEATURE OF CONCERN TO BEGIN THIS PERIOD WILL BE LINKED
TO THE NOSE OF A QUITE POWERFUL UPPER JET /IN EXCESS OF 140 KTS/
LIFTING NE UP THE APPALACHIAN MTN CHAIN WEDNESDAY. THE INCREASINGLY
DIFFLUENT UPPER PATTERN ACROSS THE MID ATLANTIC REGION LATER WED AND
WED NIGHT...WILL COMBINE WITH A SLIGHTLY ANOMALOUS SERLY LLVL FLOW
AND APPROX 1000 MB SFC LOW PRESSURE CONSOLIDATING/TRACKING RIGHT
ACROSS THE DELMARVA REGION AROUND 06Z THURSDAY.
SREF AND GEFS PLUMES /OVER THE PAST FEW DAYS/ HAVE GRADUALLY TRENDED
TOWARD HIGHER QPF AMTS IN THE FORM OF MAINLY SNOW. EC...CANADIAN AND
UKMET ALSO HAVE DISPLAYED A GRADUAL NWD SHIFT TO THE TRACK OF THEIR
SFC LOW.
USING A BLEND OF ALL THE OPERATIONAL GUIDANCE AND ENSEMBLE MEANS AT
HAND PRESENTS US WITH A FAIRLY GOOD CHANCE OF A LIGHT TO MODERATE
SNOW EVENT BEGINNING LATE WEDNESDAY AFTERNOON ACROSS THE SWRN HALF
OF THE CWA /POSSIBLY MIXED WITH SOME RAIN/...THEN SPREADING NORTH
AND EAST AT NIGHT.
NUMEROUS SREF AND GEFS PLUMES INDICATE SIGNIFICANT QPF /AOA 0.50 OF
AN INCH/ IN THE FORM OF SNOW. SREF/S MEAN 12 HOUR QPF IS AROUND 0.50
ACROSS THE EXTREME SE PART OF THE CWA...WITH THE 0.25 INCH LIQUID
EQUIVALENT LINE EXTENDING ALONG MUCH OF INTERSTATE 80 IN CENTRAL
PA...THEN ACROSS THE NRN POCONOS.
THE 06Z NAM CONTINUES TO TREND TWD HIGHER QPF AS THE MOST AGGRESSIVE
MODEL SOLUTION ATTM...AND COMPARABLE WITH SEVERAL OF THE 03Z SREF/
00Z GEFS PLUMES. THE NAM/S 24-HOUR QPF /FROM ITS APPARENT MILLER B
TYPE STORM/ IS AROUND 0.25 INCH ACROSS THE NRN TIER OF PENN...ABOUT
0.50 NEAR I-80...AND OVER 0.75 OF AN INCH ACROSS PORTIONS OF THE
LOWER SUSQ REGION.
THIS MAGNITUDE OF AN EVENT WOULD BE SOLIDLY IN THE ADVISORY
RANGE...WITH POSSIBLY BORDERLINE WINTER STORM WARNING AMOUNTS ACROSS
THE SRN HALF OF THE CWA.
AT THIS POINT...CONSIDERING MUCH UNCERTAINTY WITH RESPECT TO THE
EXACT SECONDARY LOW DEVELOPMENT NEAR THE VA COAST...AND INTERACTION
OF THE NRN AND SRN STREAM WAVES...ITS PRUDENT TO RAMP UP THE SNOW
PROBABILITIES AND AMOUNTS GRADUALLY...AND HEIGHTEN AWARENESS IN OUR
HAZARDOUS WEATHER OUTLOOK /PHLHWOCTP/.
A BRIEF PERIOD OF ZONAL FLOW ALOFT AND WEAK SFC HIGH PRESSURE WILL
BRING FAIR/MAINLY DRY WEATHER FOR THURSDAY...BEFORE A STRONG NRN
STREAM SHORTWAVE AND ASSOCIATED 135 KT...300 MB JET DIVER SEWRD TO
CARVE OUT A HIGH AMPLITUDE TROUGH ACROSS THE EASTERN THIRD OF THE
U.S. FOR THE WEEKEND. EC SHOWS 500 MB TEMPS FROM THE OHIO VALLEY TO
PENN DIVING TO PERHAPS THE COLDEST VALUES OF THE WINTER SEASON...OR
AROUND -42C. 850 MB TEMPS MAY DROP TO -16-20C. WEST TO NW MEAN LLVL
FLOW AND THE HIGHLY ANOMALOUS COLD AIR IMPLIES A SIGNIFICANT AND
PROLONGED LES/UPSLOPE SNOW EVENT FOR THE WRN MTNS AND LAKE ERIE
SNOWBELT COUNTIES.
BROAD UPPER TROFFING OVER THE EASTERN U.S. WILL LEAD TO YET
ANOTHER EAST COAST CYCLONE LATER IN THE WEEKEND. AT THIS POINT
IN TIME...THE TRACK IS WELL OFFSHORE...AT LEAST CONCERNING AFFECTS
ON PA. WRAP AROUND FLOW IS EVEN SIGNIFICANTLY
NORTHERLY...PREVENTING WIDESPREAD LAKE EFFECT SNOW SHOWER ON THE
BACK SIDE. IT HOWEVER WOULD SUPPORT AN EXTENDED COLD SPELL AS WE
HEAD INTO MID FEBRUARY.
&&
.AVIATION /22Z MONDAY THROUGH SATURDAY/...
IFR/MVFR CONDITIONS WILL IMPROVE AS THE DRY AIR MOVES THRU FOR THE
REMAINDER OF THE AFTERNOON AND WINDS SHIFT TO THE WEST.
EXPECT THE FRONT TO CLEAR EASTERN AREAS THIS EVENING WITH WESTERLY
WINDS INCREASING OVER THE REGION...GUSTING IN EXCESS OF 30KTS
LATE TONIGHT INTO EARLY TUES OVER WESTERN HIGH TERRAIN. SOME PEAK
GUSTS MAY EXCEED 40KTS. THE STRONG WINDS WILL DIRECT COLDER AIR
INTO THE REGION WITH SOME SNOW SHOWERS LIKELY ALONG THE ALLEGHENY
FRONT AND DOWNWIND OF LAKE ERIE. BLUSTERY POST-FRONTAL REGIME
WILL DOMINATE INTO TUES WITH LOWEST CIGS OVR THE NRN AND WRN MTNS.
OUTLOOK...
TUE...MVFR CIGS NORTH/WEST...BECOMING VFR BY MID DAY. VFR
ELSEWHERE WITH A SLOWLY DIMINISHING NW WIND ALL AREAS.
WED-THU...VFR EARLY. IFR/SN DEVELOPING OVER THE SOUTHERN HALF OF
THE AREA LATER WED INTO EARLY THU AS A LOW PRESSURE SYSTEM TRACKS
OFF THE MID ATL COAST.
FRI-SAT...MVFR WITH SNOW SHOWERS WEST. VFR EAST.
&&
.CTP WATCHES/WARNINGS/ADVISORIES...
WIND ADVISORY FROM 8 PM THIS EVENING TO 9 AM EST TUESDAY FOR
PAZ004>006-010>012-017-018-024-025-033-034.
&&
$$
SYNOPSIS...LA CORTE
NEAR TERM...FITZGERALD/LA CORTE
SHORT TERM...LA CORTE
LONG TERM...LAMBERT/GARTNER
AVIATION...LA CORTE
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
108 AM EST MON FEB 11 2013
.SYNOPSIS...
A FRONTAL SYSTEM WILL MOVE THROUGH THE AREA LATER TODAY...FOLLOWED
BY WINDY AND COLDER CONDITIONS TONIGHT INTO TUESDAY. LOW PRESSURE
OVER THE GULF COAST IS EXPECTED TO TRACK TOWARD THE CAROLINAS ON
WEDNESDAY...BEFORE MOVING OFF THE SOUTHERN MID-ATLANTIC COAST
WEDNESDAY NIGHT. IT MAY GET CLOSE ENOUGH TO AFFECT SOUTHERN
PENNSYLVANIA.
&&
.NEAR TERM /UNTIL 7 AM THIS MORNING/...
EVENING SATL LOOP SHOWING UPPER LOW LIFTING NE INTO S MINNESOTA.
ASSOCIATED LL JET AND PLUME OF MOISTURE AHEAD OF THIS FEATURE CAN
BE TRACED ALL THE WAY BACK TO THE EASTERN PACIFIC. ALTHOUGH PWATS
ALONG THIS LL JET ARE 2-3 STD ABV NORMAL...IT SHOULD PASS RATHER
QUICKLY THRU CENTRAL PA LATE TONIGHT AND EARLY MON AM. THEREFORE...
PRECIP AMTS NOT EXPECTED TO BE HEAVY. 18Z GEFS MEAN QPF RANGES
FROM ARND A QUARTER INCH ACROSS THE NORTH CENTRAL MTNS...TO ALMOST
0.75 INCHES ACROSS LANCASTER CO.
ALTHOUGH SURGE OF WARM AIR ALOFT ASSOC WITH LL JET SHOULD ENSURE
LIQUID PRECIP...MDL SOUNDINGS CONTINUE TO INDICATE ENOUGH COLD AIR
NR GROUND LVL FOR A PERIOD OF FZRA. 00Z PIT SOUNDING SHOWS PLENTY
OF DRY AIR IN THE LOW LVLS. SO EVEN THOUGH TEMPS ARE CURRENTLY ABV
FREEZING OVR MOST OF CENTRAL PA UNDER WAA AND OVERCAST SKIES...EXPECT
EVAPORATIVE COOLING TO LOWER SFC TEMPS JUST BLW 0C AS RAIN ARRIVES
OVERNIGHT. REGIONAL RADAR AND LATEST RAP INDICATE FZRA/RA WILL
OVERSPREAD THE W MTNS ARND MIDNIGHT...THEN SPREAD INTO THE SUSQ
VALLEY BY 3 OR 4 AM.
SREF/GEFS AND 18Z OPER RUNS ALL POINT TOWARD A MARGINAL ICING
EVENT...WITH TEMPS VERY CLOSE TO FREEZING OVERNIGHT...THEN RISING
BY DAWN. BY 12Z...BULK OF MDL DATA INDICATES ONLY THE HIGH TERRAIN
OF NORTH CENTRAL PA WILL REMAIN BLW FREEZING. SO...I ENVISION WE
WILL BE ABLE TO CHIP AWAY AT THE ADVISORY FROM SW TO NE DURING THE
EARLY AM HOURS.
GIVEN THE MARGINAL TEMPS...EXPECT ICE ACCRETION RATES TO BE LOW
AND NOT APPROACH THE LIQUID PRECIP FORECAST MENTIONED ABOVE.
ICE AMOUNTS SHOULD RANGE FROM A TRACE TO A TENTH OF AN INCH...WITH
THE LEAST AMTS WEST OF THE ALLEGHENIES ARND CONFLUENCE.
&&
.SHORT TERM /7 AM THIS MORNING THROUGH 6 PM TUESDAY/...
SHORT RANGE OPERATIONAL MODELS ARE PRETTY AGREEABLE WITH THE LL
JET AND PLUME OF ANOMALOUS PWATS SWEEPING EAST OF THE AREA BTWN
12Z-15Z...CAUSING RA/FZRA TO TAPER OFF. ANY ZR ONGOING AFTER 6AM
SHOULD QUICKLY CHANGE TO PLAIN RAIN AS TEMPS RISE INTO THE LOW TO
MID 30S BY MID MORNING.
THE DRY SLOT SOUTH OF UPPER LOW SHOULD WORK INTO CENTRAL PA BY
LATE AM...SHUTTING THE PRECIP OFF AND BRINGING PARTIAL
CLEARING...ESP DOWNWIND /EAST/ OF THE ALLEGHENIES. MDL DATA
INDICATES MUCH OF CENTRAL PA WILL BRIEFLY BREAK INTO THE WARM
SECTOR MON AFTN WITH GEFS 925 TEMPS SUPPORTIVE OF HIGHS AOA 50F
ACROSS SOUTHERN PA.
BY LATE IN THE DAY...SFC COLD FRONT WILL PUSH INTO WESTERN PA...
ACCOMPANIED BY SCT -SHRA/SN AND A GUSTY WIND SHIFT FROM SW TO
WEST. DON/T EXPECT ANY SNOW ACCUMS...AS SFC TEMPS SHOULD REMAIN
WELL ABV FREEZING THRU EARLY EVENING...EVEN OVR THE NW MTNS.
&&
.LONG TERM /TUESDAY NIGHT THROUGH SUNDAY/...
A FAIRLY AMPLIFIED SPLIT-FLOW UPPER PATTERN IS FORECAST TO
PERSIST THROUGH THE LONG TERM PERIOD ACROSS MUCH OF NORTH
AMERICA. NUMEROUS NORTHERN AND SOUTHERN STREAM SHORTWAVES WILL
BRING SEVERAL CHANCES FOR PCPN TOWARD PA DURING THE PERIOD...
THOUGH AT THIS POINT IN TIME SIGNIFICANT PCPN EVENTS DO NOT
APPEAR DESTINED FOR THE COMMONWEALTH...AT LEAST NOT DIRECTLY.
AN ABUNDANCE OF SRN STREAM FLOW WILL BRING INTRUSIONS OF ABOVE
FREEZING TEMPERATURES TO THE REGION...FURTHER COMPLICATING THE
LONG TERM FORECAST DETAILS. PHASING ENERGY MAY SUPPORT A NEARLY
FULL LATITUDE TROF SPREADING EASTWARD INTO THE EASTERN U.S. BY
NEXT WEEKEND...LEADING TO PERHAPS THE HIGHEST POTENTIAL OF
SIGNIFICANT PCPN POTENTIAL IN THE LONG TERM PERIOD.
LAKE EFFECT SHOWERS WILL BE ONGOING IN THE WEAK OF MONDAYS
SYSTEM/COLD FROPA. A WEAK RIDGE OF HIGH PRESSURE SLIDES NE ACROSS
THE STATE TUESDAY NIGHT BRINGING AN END TO THE SNOW SHOWERS.
THE NEXT SYSTEM HEADED OUR WAY FOR WEDNESDAY AFTERNOON INTO EARLY
THURSDAY IS TIED TO A RATHER VIGOROUS SOUTHERN STREAM JET EXIT
REGION. THE NOSE OF THIS 140 KT JET WILL LIFT TWD THE CENTRAL
APPALACHIANS DURING THE DAY WEDNESDAY. DETAILS OF THE EXACT
PRESSURE PATTERN AND TIMING OF A WEAK SFC LOW WEST OF THE
APPALACHIANS PER THE 06Z NAM /AND SECONDARY DEVELOPMENT NEAR THE
VA COAST/ ARE STILL A BIT SKETCHY.
LATEST...00Z GEFS IS A BIT OMINOUS AS ABOUT 20-25 PERCENT OF ITS
MEMBERS CONTAIN AROUND AN INCH OF QPF IN THE FORM OF SNOW LATE
WEDNESDAY INTO THURSDAY. SOME VARIATIONS IN THE TIMING OF THIS
PRECIP ARE ALSO NOTED.
MEAN TRACK OF THE 850 MB LOW CENTER ON THE GEFS TAKES IT ACROSS ERN
VA AND SOUTHERN DELAWARE ALONG WITH A SLIGHTLY ANOMALOUS EASTERLY
WIND AT THAT PRESSURE LEVEL. THE GEFS CONSENSUS QPF IS AROUND 0.25
INCH FOR THE LOWER SUSQ VALLEY WITH SHARPLY LESSER AMOUNTS TO THE
NW.
PAINTED HIGH CHC TO LOW LIKELY POPS INTO OUR GRIDDED DATABASE FOR
THE SE THIRD TO HALF OF THE CWA...CENTERED ON WED NIGHT WITH A
RESULTANT 1-3 INCHES OF SNOW.
THIS SYSTEM BEARS CLOSE WATCHING AS ANY INTERACTION WITH AN
UPSTREAM WAVE IN THE NRN BRANCH COULD HELP TO INVIGORATE THE
COASTAL LOW AND LLVL EASTERLY FLOW BRINGING MORE SNOW TO THE
SERN ZONES...AND SPREADING LIGHT SNOWS OVER THE I-80 CORRIDOR.
ITS CURIOUS TO NOTE THAT THE 00Z OPERATIONAL EC /THAT INITIALLY
HANDLED THE RECENT NEW ENGLAND BLIZZARD MUCH BETTER THAN THE U.S
MODELS/ IS 12-18 HOURS FASTER...AND A FEW HUNDRED KM FURTHER SOUTH
WITH THE SFC/UPPER WAVE TRACK...AND JUST BRUSHES THE MASON/DIXON
LINE WITH SOME LIGHT SNOW AT THE NRN EDGE OF THE PRECIP SHIELD.
THE AFOREMENTIONED BROAD LONGWAVE TROF MOVED ACROSS THE REGION
THURSDAY INTO NEXT WEEKEND...WITH A RETURN OF ARCTIC AIR.
WITH THE TROF WILL BE SIGNIFICANT NRN STREAM ENERGY AND AT LEAST
ONE CLIPPER SYSTEMS MOVING ACROSS NW PA ON FRIDAY WITH LE SNOW
SHOWERS PERSISTING INTO NEXT WEEKEND.
&&
.AVIATION /06Z MONDAY THROUGH FRIDAY/...
SIGNIFICANT CHANGES WERE MADE TO THE 06Z TAFS. PCPN HAS ARRIVED A
LITTLE EARLIER THAN FCST...AND TIMING OF THICKENING CLOUDS LAST
EVE HAS PRESERVED TEMPS MAINLY ABV 32F. IN ADDITION...DEWPT
DEPRESSION ARE RUNNING 10-15 DEGREES. THEREFORE...THERMAL
PROFILES ARE NO LONGER THAT FAVORABLE FOR -FZRA AND WOULD TEND TO
LEAN TOWARD -RA OR -PL PTYPES DUE TO EVAPORATIVE COOLING IN THE
LOW LEVELS. REMOVED -FZRA AND WENT WITH PLAIN RAIN FOR PREVAILING
PRES WX...WITH SOME SITES REPORTING "UP" (SLEET) FOR A BRIEF
PERIOD. KEPT LLWS AS 40-50KT SWLY LLJ TRANSLATES EWD AHEAD OF THE
APPROACHING COLD FRONT. VFR CIGS SHOULD DROP TO MVFR WITH GUIDANCE
SUGGESTING AN OUTSIDE CHC FOR IFR AT LNS/MDT. SFC WINDS WILL SHIFT
FROM S/SE TO WSW LATER TDY...VEERING MORE TO THE WEST AND
INCREASING INTO TONIGHT.
OUTLOOK...
TUE...MVFR CIGS NORTH/WEST. VFR EAST.
WED...DEVELOPING VFR TO START THE DAY. LOWER CONDITIONS POSSIBLE
OVER THE SOUTH BY LATE DAY AS A STORM SYSTEM SKIRTS THE REGION.
THUR...MAINLY VFR.
FRI...MVFR/IFR DEVELOPING OVER THE WEST AND CENTRAL TERMINALS.
VFR EAST. WINDY.
&&
.CTP WATCHES/WARNINGS/ADVISORIES...
FREEZING RAIN ADVISORY UNTIL 9 AM EST THIS MORNING FOR
PAZ004>006-010>012-017>019-024>028-033>037-041-042-045-046-
049>053-056>059-063>066.
&&
$$
SYNOPSIS...STEINBUGL
NEAR TERM...FITZGERALD
SHORT TERM...FITZGERALD/LA CORTE
LONG TERM...LAMBERT/GARTNER
AVIATION...STEINBUGL
AREA FORECAST DISCUSSION
NWS GREENVILLE-SPARTANBURG SC
947 PM EST TUE FEB 12 2013
.SYNOPSIS...
A SURFACE LOW WILL APPROACH THE CAROLINAS TOMORROW MORNING BRINGING
CLOUDY SKIES AND PRECIPITATION TO THE AREA. AS THE LOW LIFTS
NORTHEAST...HIGH PRESSURE WILL BUILD BACK INTO THE AREA LATE
WEDNESDAY AND LINGER INTO THE WEEKEND.
&&
.NEAR TERM /THROUGH WEDNESDAY/...
930 PM UPDATE...21Z SREF AND 01Z RAP SEEM TO HAVE PICKED UP ON THE
FACT THAT MOST OF THE PRECIP THIS EVENING HAS SCOOTED BY TO OUR
SOUTH...AT LEAST IN TERMS OF ACCUMULATION. MOST OBS SITES IN THE
CWFA HAVE REPORTED RAIN AT SOME POINT SO FAR...SO LLVL DRY AIR IS NO
LONGER MUCH OF A PROBLEM. DESPITE KEEPING THE HEAVIER PRECIP ALONG
THE LOWER PIEDMONT AND MIDLANDS...THE MODELS SHOW BANDS OF LIGHT
PRECIP TRANSITING THE AREA MOST OF THE NIGHT. KEPT CATEGORICAL POPS
THOUGH CHANGED COVERAGE WORDING TO PERIODS WHICH IS MORE
APPROPRIATE. SREF PROBS OF 100 J MUCAPE NEAR 100 PCT IN 09-12Z
TIMEFRAME IN OUR SOUTH...REASONABLY CONSISTENT WITH PREVIOUS
EXPECTATIONS. A FEW CELLS ARE SEEN OVER ALABAMA WHERE SAME CONDITION
PRESENT ON 03Z PROG. WILL KEEP THUNDER WORDING AS-IS. MIN TEMPS WERE
REVISED SLIGHTLY PER EVENING OBS...THOUGH LATEST GUIDANCE HAS NOT
DEVIATED MUCH FROM AFTN PACKAGE. SREF TRENDS FOR THE DEPARTURE OF
PRECIP TOMORROW SUPPORT MAINTAINING LKLY POPS THRU MIDDAY...THUS NO
CHANGES MADE TO FCST.
AT 230 PM EST TUESDAY...AN UPPER LOW OVER THE SOUTHERN PLAINS WILL
FILL TONIGHT WHILE ITS REMAINING TROUGH MOVES TO THE MS RIVER
VALLEY. THE TROUGH WILL MOVE TO THE SOUTHERN APPALACHIANS ON
WEDNESDAY. MOIST ISENTROPIC UPGLIDE WILL SET UP THIS EVENING AHEAD
OVER A WARM FRONT NEAR THE GULF COAST...AHEAD OF A SURFACE WAVE THAT
WILL MOVE NE ACROSS THE DEEP SOUTH.
THE NAM SOUNDING IS COOL ENOUGH IN THE NORTHERN MOUNTAINS FOR SOME
SNOW LATE TONIGHT...BUT THE GFS HAS MORE OF A WARM NOSE...IS
SLIGHTLY WARMER AT THE SURFACE...AND ITS MOIST LAYER IS NOT COLD
ENOUGH FOR ICE NUCLEATION. A BLEND OF THE TWO WAS USED TO PRODUCE
THIS FORECAST...AND SUPPORTED ALL RAIN THERE. MINIMUM SURFACE
TEMPERATURES WILL RUN SEVERAL CATEGORIES ABOVE NORMAL UNDER CLOUD
COVER...BUT A LOCATION OR TWO IN THE NORTHERN NC MOUNTAINS WILL
APPROACH FREEZING. AT THIS TIME THE FORECAST IS ABOVE FREEZING AT
ALL SITES...AND NO FREEZING RAIN IS BEING CARRIED IN THE FORECAST.
RAIN ASSOCIATED WITH THIS LIFT IS EXPECTED TO FROM IN SITU COLD AIR
DAMMING OVER OUR AREA ON WEDNESDAY...LIMITING WARMING. AS THE
SURFACE WAVE MOVES BY IN THE AFTERNOON...DRIER AIR WILL WORK INTO
THE AREA FORM THE SW...LOWERING THE CHANCE OF PRECIPITATION. MOIST
NW FLOW BEHIND THE WAVE WILL SUPPORT LINGERING SHOWERS IN THE NC
MOUNTAINS LATE IN THE DAY... WHERE COLD ADVECTION WILL SUPPORT A
CHANGE OVER TO SNOW AT HIGHER ELEVATIONS.
&&
.SHORT TERM /WEDNESDAY NIGHT THROUGH FRIDAY/...
AS OF 245 PM TUESDAY...SHORT WAVE AND SFC LOW PRESSURE MOVE NE AWAY
FROM THE AREA WED NITE WITH NEARLY ZONAL FLOW AND SFC HIGH PRESSURE
BRIEFLY BUILDING IN FOR THU. GUIDANCE STILL HAS NW FLOW AND
LINGERING LOW LEVEL MOISTURE ACROSS THE NC MTNS WED NITE. HOWEVER...
THE GUIDANCE IS NOT AS BULLISH ON PRECIP. STILL...THERE LOOKS TO BE
ENUF LIFT...MOISTURE AND CAA FOR A PERIOD OF NW FLOW SNOW DURING THE
EVENING WHICH THEN TAPERS OFF AFTER MIDNIGHT. IN FACT...MOISTURE
DIMINISHES SO QUICKLY FROM TOP DOWN THAN THE PRECIP COULD END AS A
PERIOD OF FREEZING RAIN OR DRIZZLE. EITHER WAY...IT LOOKS LESS
LIKELY FOR ANY SIGNIFICANT PRECIP OF ANY KIND OVERNIGHT...WITH
AROUND AN INCH OF SNOW EXPECTED IN THE HIGHER ELEVATIONS OF THE NRN
MTNS AND UP TO AN INCH IN THE HIGHER ELEVATIONS OF THE SMOKIES.
EXPECT CLOUDS TO LINGER THRU THE NIGHT ACROSS THE MTNS EVEN WHERE
PRECIP IS LIMITED. WINDY CONDITIONS DURING THE EVENING DIMINISH
OVERNIGHT AS WELL. LOWS WILL BE NEAR NORMAL.
ELSEWHERE...SKIES CLEAR AND PRECIP ENDS QUICKLY DURING THE EVENING
WITH MOSTLY CLEAR SKIES OVERNIGHT. BREEZY CONDITIONS DURING THE
EVENING DIMINISH OVERNIGHT AS WELL. LOWS WILL BE A FEW DEGREES ABOVE
NORMAL.
SKIES CLEAR ACROSS THE NC MTNS THU MORNING WITH SUNNY SKIES
ELSEWHERE THRU THE DAY. BREEZY SW WINDS DEVELOP DURING THE AFTERNOON
WITH HIGHS UP TO 5 DEGREES ABOVE NORMAL ALL AREAS. WITH DOWNSLOPE
FLOW WARMING TEMPS INTO THE MID 50S TO LOW 60S OUTSIDE THE MTNS.
A DEEP TROF BEGINS TO DEVELOP ACROSS THE CENTRAL AND ERN US ON FRI
AS A WEAK SHORT WAVE MOVES OVER THE AREA. THIS SHORT WAVE PUSHES A
WEAK DRY COLD FRONT ACROSS THE AREA FRI. THERE WILL BE ENUF MOISTURE
FOR INCREASING CLOUDS ACROSS THE MTNS AND NC FOOTHILLS/PIEDMONT FRI
WITH MOSTLY SUNNY SKIES ELSEWHERE. EXPECT BREEZY SW WINDS FRI
MORNING TO BECOME W TO NW BY AFTERNOON. LOWS THU NITE WILL BE A FEW
DEGREES ABOVE NORMAL...WHILE HIGHS FRI WILL BE NEAR NORMAL MTNS AND
UP TO 5 DEGREES ABOVE NORMAL ELSEWHERE.
&&
.LONG TERM /FRIDAY NIGHT THROUGH TUESDAY/...
AS OF 225 PM TUESDAY...THE GLOBAL MODELS CONTINUE TO DEPICT A BRIEF
PATTERN CHANGE OVER THE WEEKEND...AS A SERIES OF SHORT WAVE TROUGHS
DIVING OUT OF THE NORTHERN CONUS CARVE OUT A DEEP LONG WAVE TROUGH
OVER THE EASTERN STATES DURING THE WEEKEND. THIS PATTERN WILL BRING
MUCH COOLER WEATHER TO THE REGION...AND POSSIBLY PERIODS OF
NORTHWEST FLOW SNOW SHOWERS TO THE MTNS. A POTENT SHORT WAVE IS
EXPECTED TO MOVE OVER THE SOUTHEAST STATES IN THE SATURDAY/SAT NIGHT
TIME FRAME. IT IS INTERESTING THAT THE MODELS SUGGEST THAT THIS
FEATURE WILL TAKE ON A NEGATIVE TILT AFTER IT LIFTS AWAY FROM THE
COAST...RESULTING IN RAPID CYCLOGENESIS. THIS SCENARIO WOULD HAVE NO
EFFECT ON THE SENSIBLE WEATHER OVER OUR AREA...BUT IF THE TRANSITION
TO A NEGATIVE TILT OCCURS SOONER...THINGS COULD GET INTERESTING.
OTHERWISE...THE TROUGH AXIS WILL SHIFT OFF THE EAST COAST BY THE END
OF THE WEEKEND...ALLOWING FOR A RETURN TO NEAR SEASONAL TEMPERATURES
BY MONDAY/TUESDAY. THE GLOBAL MODELS ARE IN QUITE GOOD AGREEMENT
THAT LARGE SCALE HEIGHT FALLS WILL BE OCCURRING ACROSS MUCH OF THE
EASTERN HALF OF THE CONUS BY THE END OF THE PERIOD...AS A MAJOR
SHORT WAVE TROUGH DIVES OUT OF THE CENTRAL/NORTHERN ROCKIES. AS A
RESULT...THE GFS AND ECMWF ARE DEPICTING A RATHER WET DAY 7 ACROSS
THE SOUTHEAST...SO CHANCE POPS HAVE BEEN INTRODUCED. ATTM...IT
APPEARS THAT THE PATTERN WILL BE SUCH THAT WINTRY PRECIP WILL NOT BE
A SIGNIFICANT CONCERN.
&&
.AVIATION /03Z WEDNESDAY THROUGH SUNDAY/...
AT KCLT...LIGHT RAIN FALLING FROM MIDLEVEL VFR CIG AS OF 00Z WITH
CALM WINDS. AS DEVELOPING SFC LOW PRESSURE MOVES NORTHEASTWARD FROM
THE CENTRAL GULF COAST TONIGHT...LOW LEVEL WARM AIR AND MOISTURE
ADVECTION WILL BRING INCREASINGLY WIDESPREAD RAIN AND LOWERING CIGS.
UPSTREAM OBS AND SHORT TERM GUIDANCE WOULD POINT TO MVFR CIGS AND
VSBY FOR MOST OF THE NIGHT...ONCE ENOUGH RAIN MOVES IN TO MOISTEN
THE LOW LEVELS. THE LLVL LIFT PEAKS LATE TONIGHT AND EARLY WED AND
GUIDANCE BRINGS IN IFR CIGS FOR A TIME. THE LOW PRESSURE TRACKS
THROUGH THE SRN APPALACHIANS BY WED AFTN TAKING THE FORCING WITH
IT...AT WHICH TIME RESTRICTIONS WILL BEGIN TO LIFT. SHOULD BE BACK
TO MVFR BY EARLY AFTN AS THE RAIN TAPERS OFF WITH VFR CLOUDS
BEGINNING TO SCATTER BY 21Z. SOME 20 KT OR STRONGER WINDS WILL BE
NOT TOO FAR OFF THE SFC AND ONCE CLOUDS START TO BREAK UP THESE
WINDS SHOULD BE REACHED BY MIXING. NORTHERLY WINDS TONIGHT WILL
SWING SOUTHEAST BY MORNING AND THEN SOUTHWEST AS THE LOW MOVES PAST.
ELSEWHERE...VFR THIS EVENING AHEAD OF RAINFALL MOVING IN FROM THE
SOUTHWEST. RAIN WILL INITIALLY BE RATHER LIGHT AS IT FALLS INTO DRY
NEAR SFC AIR...BUT INCREASING MOISTURE ADVECTION ALOFT AHEAD OF THE
SFC LOW WILL BOTH REDUCE EVAPORATION AND INCREASE RAIN PRODUCTION.
CIGS SHOULD EASILY GO MVFR BY LATE EVENING OVER THE SOUTHERN SITES
AND BY EARLY MORNING TO THE NORTH. FURTHER DEEPENING MOISTURE
EXPECTED TO LOWER CIGS TO IFR CLOSER TO DAYBREAK...WITH SOME LIGHT
FOG REDUCING ALREADY RAIN-LIMITED VSBY. CIGS WILL PROBABLY DOMINATE
THE RESULTING CATEGORY HOWEVER. RAIN EXPECTED TO TAPER OFF BY LATE
MORNING OVER THE SOUTH WITH THE BACK EDGE PROGRESSING NORTHWARD FROM
THERE...FOLLOWED BY A SIMILAR CLEARING TREND. WEAK NORTHERLY WINDS
TONIGHT WILL GENERALLY VEER AS THE LOW APPROACHES AND THEN PASSES
SITES...BECOMING SOUTHWEST BY THE END OF THE PERIOD AT ALL SITES
/EXCEPT KAVL WHICH GOES NORTHWEST/. GUSTS INTO THE 20-30 KT RANGE
ARE LIKELY WED AFTN ESPECIALLY IN THE MTNS AND WESTERN UPSTATE WHERE
COLDER AIR WILL BE FIRST TO MOVE IN ALOFT AND ENHANCE MIXING
POTENTIAL.
OUTLOOK...LOW PRESSURE WILL EXIT TO THE EAST BY WEDNESDAY
NIGHT...ENDING RESTRICTIVE CIGS AND VSBYS. HIGH PRESSURE IS EXPECTED
TO BRING BETTER CONDITIONS FOR THURSDAY.
CONFIDENCE TABLE
03-09Z 09-15Z 15-21Z 21-03Z
KCLT HIGH 80% LOW 57% HIGH 87% HIGH 87%
KGSP MED 77% LOW 55% HIGH 83% HIGH 91%
KAVL MED 71% MED 67% HIGH 92% HIGH 95%
KHKY HIGH 94% MED 76% HIGH 90% MED 66%
KGMU MED 75% MED 60% HIGH 85% HIGH 91%
KAND MED 67% MED 69% HIGH 88% HIGH 87%
THE PERCENTAGE REFLECTS THE NUMBER OF GUIDANCE MEMBERS AGREEING
WITH THE SCHEDULED TAF ISSUANCE FLIGHT RULE CATEGORY. COMPLETE HOURLY
EXPERIMENTAL AVIATION FORECAST CONSISTENCY TABLES AND ENSEMBLE FORECASTS
ARE AVAILABLE AT THE FOLLOWING LINK: (MUST BE LOWER CASE)
WWW.WEATHER.GOV/GSP/AVIATION_TABLES
&&
.GSP WATCHES/WARNINGS/ADVISORIES...
GA...NONE.
NC...NONE.
SC...NONE.
&&
$$
SYNOPSIS...JPT
NEAR TERM...JAT/WIMBERLEY
SHORT TERM...RWH
LONG TERM...JDL
AVIATION...WIMBERLEY
AREA FORECAST DISCUSSION...UPDATED
NWS SAN ANGELO TX
1142 PM CST SUN FEB 10 2013
.DISCUSSION...
SEE AVIATION SECTION.
&&
.AVIATION...
VFR CONDITIONS WILL PREVAIL AT THE TAF SITES OVERNIGHT THROUGH
MONDAY AFTERNOON. HIGH CLOUD COVERAGE WILL INCREASE OVERNIGHT
WHILE PATCHY MID-LEVEL CLOUDS DEVELOP. A FEW SPRINKLES OR A
BRIEF LIGHT RAIN SHOWER ARE A POSSIBILITY AT KBBD...KJCT AND
KSOA. A BACK DOOR TYPE COLD FRONT WILL SAG SOUTH ACROSS THE BIG
COUNTRY OVERNIGHT...AND SHOULD BECOME NEARLY STATIONARY ACROSS THE
NORTHERN CONCHO VALLEY AND HEARTLAND AREAS ON MONDAY. AT
KABI...WINDS WILL BECOME EAST OVERNIGHT AND REMAIN MOSTLY FROM THE
EAST ON MONDAY. LIGHT WINDS AT THE OTHER TAF SITES OVERNIGHT WILL
BECOME EAST TO SOUTHEAST ON MONDAY. CLOUD CEILINGS WILL DECREASE
MONDAY EVENING AND MONDAY NIGHT...AND ARE EXPECTED TO BE IN THE
RANGE OF 2500-3500 FT DURING THE FINAL 4-6 HOURS OF THE TAF
PERIOD. SCATTERED RAIN SHOWERS ARE POSSIBLE MONDAY EVENING AND
MONDAY NIGHT...AND CARRYING VICINITY SHOWERS IN THE AREA TAFS
DURING THAT TIME.
19
&&
.PREV DISCUSSION... /ISSUED 547 PM CST SUN FEB 10 2013/
DISCUSSION...
SEE AVIATION SECTION.
AVIATION...
VFR CONDITIONS WILL PREVAIL AT THE TAF SITES TONIGHT AND MONDAY.
SOME INCREASE IN HIGH CLOUD COVERAGE IS EXPECTED TONIGHT. SOME
MID-LEVEL CLOUD DEVELOPMENT IS EXPECTED ACROSS SOUTHERN SECTIONS
OF WEST CENTRAL TEXAS LATE TONIGHT AND MONDAY. A FEW SPRINKLES
OR PERHAPS A LIGHT RAIN SHOWER IS POSSIBLE MONDAY...TO THE EAST
OF THE KJCT AND KBBD TERMINALS. WINDS WILL BE LIGHT AND VARIABLE
TONIGHT. EAST-SOUTHEAST WINDS WILL DEVELOP ON MONDAY AND INCREASE
TO 8-12 KT.
19
PREV DISCUSSION... /ISSUED 349 PM CST SUN FEB 10 2013/
SHORT TERM...
RELATIVELY QUIET WEATHER CONDITIONS IN THE SHORT TERM PERIOD.
A WEAK FRONT WILL ENTER THE BIG COUNTRY LATE TONIGHT BUT WILL
WASH OUT ACROSS THE AREA ON MONDAY. SUBTROPICAL JET WILL CONTINUE
TO FEED MID AND HIGH LEVEL MOISTURE FROM THE SOUTHWEST ACROSS MAINLY
SOUTHERN SECTIONS OVERNIGHT. THE NAM CONTINUES TO SHOW SOME LIGHT
RAIN SHOWERS DEVELOPING OVER EXTREME SOUTHEAST COUNTIES ON MONDAY IN
AN AREA OF WEAK ISENTROPIC ASCENT/WAA. 3KM WRF AND LATEST RUC ALSO
HINTING AT THIS POSSIBILITY SO WILL KEEP SLIGHT CHANCE POPS INTACT
THIS FORECAST CYCLE. CLOUD COVER WILL LIMIT COOLING ACROSS SOUTHEAST
SECTIONS TONIGHT WITH LOWS MAINLY IN THE LOWER 40S. LIMITED CLOUD
COVER...LIGHT WINDS AND A DRY AIRMASS WILL ALLOW TEMPS TO COOL INTO
THE LOW TO MID 30S ACROSS THE REMAINDER OF THE AREA. MID AND HIGH
CLOUDS WILL CONTINUE TO INCREASE ON MONDAY WITH AFTERNOON HIGHS
RANGING FROM THE LOW TO MID 60S NORTH TO THE MID AND UPPER 60S
SOUTH.
24
LONG TERM...
UPPER LOW NEAR THE FOUR CORNERS LATE MONDAY WILL WILL DIG
SOUTHEAST TUESDAY INTO NEW MEXICO. SURFACE TO 850MB LAYER WILL
QUICKLY SATURATE OVER THE ENTIRE CWA BY MIDNIGHT MONDAY
CONCOMITANT WITH AN INTENSIFYING LLJ...40-50KT CENTERED OVER THE
SOUTHWESTERN CWA. THE HEAVIEST RAINFALL ACCUMULATION CHANCES WILL
BE OVER THE BIG COUNTRY ON THE NOSE OF THE LOW LEVEL JET
BEGINNING AROUND MIDNIGHT MONDAY AND LASTING INTO TUESDAY
MORNING. HAVE INCLUDED THE MENTION OF CONVECTIVE ACTIVITY MONDAY
NIGHT THROUGH TUESDAY AS THE COLD FRONT/DRYLINE MOVES EAST
THROUGH THE FORECAST AREA. LATEST SPC CONVECTIVE OUTLOOK MENTIONS
VIA A SEE TEXT THE POSSIBILITY FOR LARGE HAIL FOR OUR AREA BASED
ON SUFFICIENT INSTABILITY AND SHEAR VALUES FOR ELEVATED
SUPERCELLS...AS REFLECTED IN THE LATEST FORECAST SOUNDINGS...WILL
CONTINUE TO EVALUATE THIS POSSIBILITY. PRECIPITATION CHANCES WILL
BE CONFINED TO OUR EASTERN TIER OF COUNTIES BY TUESDAY AFTERNOON
WITH PRECIPITATION ENDING OVER ALL OF THE FORECAST AREA BY TUESDAY
EVENING. TUESDAY MORNING LOWS WILL RANGE FROM THE LOWER 40S TO
AROUND 50 DEGREES AND TUESDAY AFTERNOON HIGHS WILL RANGE FROM THE
MID 50S TO THE MID 60S UNDER CLOUDY SKIES.
AFTERNOON HIGHS AND MORNING LOWS WILL REMAIN NEAR CLIMO THROUGH
THE COMING WEEKEND...GENERALLY IN THE LOWER 60S FOR HIGHS AND THE
MID 30S FOR LOWS. THE NEXT COLD FRONTAL PASSAGE WILL BE LATE
THURSDAY WITH LITTLE IMPACT ON THE FORECAST AREA.
15
&&
.PRELIMINARY POINT TEMPS/POPS...
ABILENE 33 64 46 58 32 / 0 5 60 40 10
SAN ANGELO 34 70 50 64 35 / 0 10 50 10 5
JUNCTION 43 68 45 66 35 / 0 20 50 20 10
&&
.SJT WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
AREA FORECAST DISCUSSION...UPDATED
NWS FORT WORTH TX
1113 PM CST SUN FEB 10 2013
.UPDATE...
ALTHOUGH THERE IS DRY AIR IN THE LOWER 8000 FEET OF THE
ATMOSPHERE...RADAR RETURNS HAVE INCREASED TO THE POINT WHERE SOME
SPRINKLES OR PATCHES OF LIGHT RAIN ARE LIKELY OVERNIGHT ACROSS
THE AREA SOUTH OF A COMANCHE TO MCKINNEY TO COOPER LINE. THUS
HAVE ADDED A 10 PERCENT CHANCE OF LIGHT RAIN IN THOSE AREAS.
58/91
&&
.AVIATION...
VFR CONDITIONS ARE EXPECTED THROUGH 06Z TUESDAY. LIGHT WEST TO
NORTHWEST WINDS THIS EVENING WILL BECOME NORTHEAST AT 5 TO 10
KNOTS BEFORE DAYBREAK AND EASTERLY MONDAY AFTERNOON. THERE WILL
BE SOME LOW RAIN CHANCES LATE MONDAY AFTERNOON THROUGH THE
EVENING IN THE METROPLEX...BUT THE CHANCES ARE NOT HIGH ENOUGH
TO MENTION IN THE TAFS. RAIN CHANCES MONDAY AFTERNOON IN THE WACO
AREA MAY PROMPT THE ADDITION OF VCSH WITH THE 03Z UPDATES. RAIN
CHANCES WILL IMPROVE AREA WIDE AFTER MIDNIGHT.
58
&&
.PREV UPDATE...
.UPDATE...
ONLY SOME MINOR CHANGES NEEDED TO THE CURRENT FORECAST. WATER
VAPOR IMAGERY SHOWS THE POWERFUL UPPER STORM THAT BROUGHT LAST
NIGHTS WEATHER NOW MOVING INTO THE UPPER MIDWEST. THERE IS ANOTHER
UPPER TROUGH OVER THE WESTERN US AND THIS IS HELPING KEEP NORTH
TEXAS IN A FAST SOUTHWEST FLOW ALOFT. FORT WORTH RAOB SAMPLED A
150KT UPPER JET AT 230MB. THERE IS SOME MOISTURE ALSO STREAMING
OVERHEAD AS INDICATED BY THE PARTIAL CLOUD COVER. FARTHER
SOUTH...MOISTURE IS A LITTLE BETTER AND RAP FORECAST SOUNDINGS
ACTUALLY INDICATE SOME SATURATION ABOVE 600MB. THIS IS RESULTING
IN SOME LIGHT PRECIPITATION ACROSS THE FAR SOUTHERN
COUNTIES...HOWEVER GIVEN THE DRY AIR BENEATH IT...MOST OF THE
RETURNS ON THE RADAR ARE VIRGA. NOT EXPECTING ANY PRECIP TO REACH
THE GROUND OVERNIGHT TONIGHT. BETTER RAIN CHANCES WILL ARRIVE LATE
TOMORROW AND PERSIST INTO TUESDAY.
CHANGES TO CURRENT FORECAST WERE LIMITED TO HOURLY TEMPERATURES
AND SKY COVER.
DUNN
&&
.PREV DISCUSSION... /ISSUED 348 PM CST SUN FEB 10 2013/
AFTERNOON WATER VAPOR SATELLITE IMAGERY INDICATED A POWERFUL UPPER
LOW OVER THE NORTH PLAINS WITH A STRONG SHORTWAVE TROUGH LOCATED
OVER EASTERN NEVADA. AFTERNOON SURFACE OBSERVATIONS SHOWED
WESTERLY WINDS OVER ALL OF NORTH AND CENTRAL TX...THE RESULT OF A
PACIFIC TYPE COLD FRONT THAT MOVED THROUGH OVERNIGHT AND WAS
ACCOMPANIED BY A LINE OF STRONG TO SEVERE THUNDERSTORMS.
PERSISTENT WESTERLY FLOW HAS ADVECTED A VERY DRY AIR MASS OVER
NORTH TX THIS AFTERNOON WITH DEW POINTS OBSERVED IN THE TEENS WEST
OF THE INTERSTATE 35 CORRIDOR AND IN THE UPPER 20S TO LOWER 30S TO
THE EAST. PERSISTENT CLOUD COVER HAS HELD TEMPERATURES IN THE MID
60S FOR MOST LOCATIONS...DESPITE THE DRY AIR IN PLACE.
TONIGHT THROUGH WEDNESDAY...THE NEVADA SHORTWAVE TROUGH WILL
CONTINUE TO SINK SOUTH-SOUTHEAST THROUGH TOMORROW MORNING AS IT
MERGES WITH A SECOND...COMPACT AND VERY FAST MOVING...TROUGH
COMING OUT OF WESTERN CANADA. AS THIS TROUGH APPROACHES THE REGION
IT WILL SPREAD LARGE SCALE FORCING FOR ASCENT OVER THE
CWA...RESULTING IN AN INCREASE IN LOW LEVEL CLOUD COVER FROM
SOUTHEAST TO NORTHWEST THROUGH MONDAY AFTERNOON. THIS MOISTURE
RETURN WILL LIKELY RESULT IN ISOLATED RAIN SHOWERS DEVELOPING
ALONG AND SOUTHEAST OF AN ATHENS TO GATESVILLE LINE MONDAY
MORNING...SPREADING NORTHWEST TOWARDS THE DFW METROPLEX BY MONDAY
AFTERNOON. DUE TO THE VERY DRY AIR CURRENTLY IN PLACE...THINK THAT
RAINFALL WILL BE LIGHT IN NATURE...WITH INITIAL RAIN SHOWERS
WORKING TO SATURATE THE NEAR SURFACE LAYER FROM THE TOP DOWN
RESULTING IN VIRGA AND LOWERING CLOUD DECKS. HIGHS ON MONDAY WILL
LIKELY STRUGGLE TO REACH 60 DEGREES FOR THE SOUTHEASTERN PORTIONS
OF THE CWA WITH MOSTLY CLOUDY SKIES AND ISOLATED RAIN SHOWERS TO
CONTEND WITH. ELSEWHERE HIGHS WILL LIKELY ONLY REACH THE LOWER
60S.
ISOLATED RAIN SHOWERS WILL SPREAD NORTH OVER THE ENTIRE CWA MONDAY
EVENING AS THE TROUGH BEGINS TO MOVE EAST-NORTHEAST TOWARDS THE
SOUTH PLAINS. MOST GUIDANCE BRINGS NUMEROUS RAIN SHOWERS OVER
NORTH AND CENTRAL TX LATE MONDAY NIGHT AND INTO TUESDAY MORNING AS
THE BEST LARGE SCALE FORCING FOR ASCENT MOVES OVER NORTH TX. DID
NOT MAKE ANY REAL CHANGE TO THE PREVIOUS FORECAST DURING THIS
PERIOD AS LIKELY /60 TO 70/ POPS SEEM APPROPRIATE FOR THE EXPECTED
COVERAGE OF RAIN SHOWERS MONDAY NIGHT INTO TUESDAY MORNING.
MAINTAINED THE MENTION OF ISOLATED THUNDERSTORMS EMBEDDED IN THE
MORE WIDESPREAD RAIN SHOWER ACTIVITY BECAUSE BOTH THE GFS AND
ECMWF INDICATE THAT WE WILL RECEIVE A GOOD INFLUX OF MID TO UPPER
LEVEL MOISTURE AS A WEAK SHORTWAVE TROUGH OVER THE OPEN WATERS OF
THE PACIFIC IS DRAWN OVER THE REGION DURING THIS TIME. MOST OF THE
RICH/TROPICAL MOISTURE ASSOCIATED WITH THIS FEATURE WILL BE
SCOURED OUT BY THE HIGH TERRAIN OF MEXICO...BUT WHAT REMAINS WILL
CERTAINLY HELP SUPPORT WIDESPREAD RAIN SHOWERS MONDAY NIGHT AND
TUESDAY MORNING. AS OPPOSED TO OUR LAST SYSTEM...MODELS DO NOT
FORECAST STEEP MID-LEVEL LAPSE RATES BEFORE PRECIPITATION
BEGINS...SO THINK THAT ANY EMBEDDED THUNDERSTORMS ARE VERY
UNLIKELY TO PRODUCE SEVERE WEATHER AT THIS TIME.
AS THE WEAK PACIFIC OCEAN ENERGY MOVES EAST OF THE REGION...IT
WILL BE REPLACED BY A GOOD MID TO UPPER LEVEL DRY SLOT WORKING IN
BEHIND OUR NEVADA SHORTWAVE WHICH IS EXPECTED TO MOVE EAST...RIGHT
ALONG THE RED RIVER DURING THE DAY ON TUESDAY. THIS DRY SLOT WILL
BRING AND END TO PRECIPITATION OVER THE CWA FROM SOUTHWEST TO
NORTHEAST TUESDAY AFTERNOON AS THE DRY SLOT WORKS TO DRY OUT THE
ATMOSPHERE FROM THE TOP DOWN.
DEPENDING ON THE EXACT TRACK OF THE NEVADA SHORTWAVE TROUGH...WE
MAY SEE SOME PRECIPITATION LINGER JUST SOUTH OF THE RED RIVER
TUESDAY EVENING AS COLDER AIR BUILDS INTO THE REGION FROM THE
NORTHWEST. THE CONSENSUS OF 10/12Z GUIDANCE CONTINUES TO INDICATE
THAT THE TROUGH WILL MOVE EAST RIGHT ALONG THE RED RIVER WHICH
KEEPS ANY CHANCE OF A CHANGE OVER TO SNOW NORTH OF THE RED RIVER
AT THIS TIME. EVEN THE ECMWF...WHICH HAS BEEN MOST AGGRESSIVE WITH
COLD AIR ADVECTION ON THE BACK SIDE OF THIS TROUGH...KEEPS
TEMPERATURES NEAR THE RED RIVER IN THE UPPER 30S WHILE THERE IS
STILL ENOUGH MOISTURE IN PLACE FOR PRECIPITATION TO DEVELOP NEAR
THE CWA. AS A RESULT...KEPT A SLIGHT CHANCE FOR RAIN/RAIN SHOWERS
IN THE FORECAST NEAR THE RED RIVER THROUGH MIDNIGHT/06Z TUESDAY
NIGHT.
EXTENDED...COLDER AIR WILL BUILD INTO NORTH AND CENTRAL TX BEHIND
THE NEVADA SHORTWAVE TROUGH. HOWEVER PERSISTENT NORTHWEST/WESTERLY
FLOW WILL ONCE AGAIN SCOUR LOW LEVEL MOISTURE WELL AWAY FROM THE
REGION REDUCING THE CHANCE OF ANY PRECIPITATION THROUGH THE
REMINDER OF THE WEEK. WE ARE EXPECTED TO REMAIN IN A SOMEWHAT
ACTIVE/FAST FLOW REGIME ALOFT WHICH WILL SEND A COUPLE OF WEAK
UPPER LEVEL DISTURBANCES OVER THE CWA FOR THE LATTER HALF OF THE
UPCOMING WORK WEEK. NONE OF THESE DISTURBANCES IS PARTICULARLY
IMPRESSIVE IN NATURE IN TERMS OF ABILITY TO SPREAD LARGE SCALE
FORCING FOR ASCENT OVER THE REGION. WE WILL LIKELY SEE SKIES CLOUD
UP AS EACH DISTURBANCE PASSES BY...BUT WITHOUT BETTER MOISTURE TO
WORK WITH...THINK THAT CHANCE OF ANY PRECIPITATION WILL REMAIN LOW
THROUGH THE END OF THE WEEK.
THE ECMWF HAD BEEN DRAGGING A STRONG BUT POSITIVELY TILTED TROUGH
OVER THE SOUTH PLAINS AT THE END OF THE WEEK. THIS WOULD HAVE
SPREAD MORE PERSISTENT LARGE SCALE FORCING FOR ASCENT OVER THE CWA
WHICH MAY HAVE RESULTED IN SOME LIGHT PRECIPITATION...AND POSSIBLY
EVEN SOME WINTRY WEATHER. HOWEVER TODAYS 12Z ECMWF IS IN MUCH
BETTER AGREEMENT WITH THE GFS WHICH KEEPS A LARGE TROUGH OVER THE
NORTHEASTERN CONUS...WITH ONLY TRANSIENT/WEAK DISTURBANCES
PROVIDING LIFT OVER THE CWA THROUGH NEXT WEEKEND. AS A RESULT
MAINTAINED A DRY FORECAST THROUGH NEXT WEEKEND...WITH TEMPERATURES
HOLDING NEAR OR MAYBE SLIGHTLY BELOW SEASONAL NORMALS AS EACH
UPPER DISTURBANCE SENDS A REINFORCING SHOT OF COOL AIR INTO NORTH
AND CENTRAL TX.
CAVANAUGH
&&
.PRELIMINARY POINT TEMPS/POPS...
DALLAS-FT. WORTH, TX 42 60 45 54 38 / 10 10 50 70 10
WACO, TX 44 62 48 63 40 / 10 20 50 50 10
PARIS, TX 39 60 42 46 38 / 5 10 30 70 20
DENTON, TX 40 61 44 49 36 / 5 10 50 70 20
MCKINNEY, TX 40 61 44 49 37 / 5 10 50 70 20
DALLAS, TX 42 60 46 55 39 / 10 10 50 70 10
TERRELL, TX 42 60 45 55 39 / 10 20 40 70 10
CORSICANA, TX 46 58 47 59 41 / 10 20 40 60 10
TEMPLE, TX 47 63 49 65 40 / 10 30 50 50 10
MINERAL WELLS, TX 37 62 44 56 35 / 5 10 60 50 10
&&
.FWD WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
58/91
FOR FREQUENTLY ASKED QUESTIONS ABOUT THE AREA FORECAST DISCUSSION
VISIT...
HTTP://WEATHER.GOV/SALTLAKECITY/GENERAL/AFD_FAQS.PHP (ALL LOWER CASE)
AREA FORECAST DISCUSSION
NWS BLACKSBURG VA
1235 AM EST MON FEB 11 2013
.SYNOPSIS...
A WARM FRONT WILL LIFT NORTHEAST ACROSS THE REGION LATER TONIGHT
FOLLOWED BY A TRAILING COLD FRONT THAT WILL SWEEP EAST THROUGH THE
AREA MONDAY. ANOTHER STORM SYSTEM LOOKS TO MOVE NORTHEAST ACROSS
THE EASTERN CAROLINAS ON WEDNESDAY...POSSIBLY RESULTING IN THE
NEXT ROUND OF WINTRY WEATHER FOR MIDWEEK.
&&
.NEAR TERM /THROUGH TODAY/...
AS OF 930 PM EST SUNDAY...
WELL...BAND OF SLEET/SOME SNOW AND RAIN MOVED IN CAUSING SOME
MINOR TRAVEL ISSUES. THE DUAL POL HAS DONE AN EXCELLENT JOB OF
DEPICTING THIS. CURRENTLY...SOME SLEET STILL BEING OBSERVED OVER
THE ROANOKE VALLEY. RADAR INDICATES POCKETS OF SLEET AND GIVEN THE
DRY AIRMASS...SHOULD SEE THINGS WET BULB ENOUGH TO BRING SLEET TO
THE PIEDMONT BUT NO ACCUMULATION HERE GIVEN WARMER TEMPS. OVER THE
ALLEGHANY HIGHLANDS OF BATH INTO PORTIONS OF GREENBRIER COULD SEE
A FEW TENTHS OF AN INCH OF SNOW/SLEET.
THE LATEST RUC HAD THIS NAILED AS FAR AS HAVING A NARROW BAND OF
PRECIP AND DRYING IT OUT TO THE WEST. HAVE SINCE FOLLOWED THIS
MODEL UNTIL DAWN...BUT LEFT ROOM IN FOR DEVELOPMENT OF LIGHT
PRECIP IN THE WEST...BUT ONLY SLIGHT TO LOW CHANCE. MOST AREAS
OVERNIGHT WILL BE DRY. WARM FRONT EDGES NWD...BUT IN-SITU WEDGE
WILL HOLD AT LEAST UNTIL MID MORNING MONDAY BEFORE THE COLD FRONT
ARRIVES. WILL KEEP IT CLOUDY ALL NIGHT. RUC DOES SHOW SOME HIGHER
OMEGA RETURNING OVER THE SOUTHERN CWA OVERNIGHT SO KEPT POPS
HIGHER HERE. SO IN SUMMARY CUT POPS BACK FROM EARLIER FORECAST.
TEMPS COOL SOME WITH PRECIP BUT THERE IS MORE OF AN INCREASE IN
THE DEWPOINTS. THINK TEMPS STAY STEADY IN THE WEDGE OR SLOWLY FALL
WHILE STEADY OR SLOWLY RISING TEMPS OCCUR OVER THE FAR SW OUTSIDE
THE WEDGE BARRING ANY PRECIP.
THE WINDS WILL BE STRONGEST BETWEEN THIS AFD AND ABOUT 08Z...WHEN
SFC WINDS TURN MORE SSW. COULD BE A FEW GUST ON THE HIGHER RIDGES
LIKE MT ROGERS OVER 50 KNOTS...BUT ISOLATED NATURE AND WILL NOT
UPGRADE TO HIGH WIND WARNING.
PREVIOUS VALID DISCUSSION...
A COLD FRONT WILL SWEEP EAST MONDAY. MOST OF THE RAIN WILL END
BY MID MORNING MONDAY. IT SHOULD BE WINDY MONDAY WITH DEEP MIXING
TO JUST ABOVE H8 AND A WESTERLY DOWNSLOPING FLOW. WIND SPEEDS WILL
BE NEAR ADVISORY CRITERIA LEVELS WITH WIND GUSTS ACROSS NORTHWEST
NORTH CAROLINA AND INTO THE NEW RIVER VALLEY. HIGHS MONDAY WILL BE
MILD WITH READINGS FROM THE LOWER 50S IN THE NORTHWEST TO THE MID
60S IN THE SOUTHEAST.
&&
.SHORT TERM /TONIGHT THROUGH WEDNESDAY NIGHT/...
AS OF 345 PM EST SUNDAY...
MONDAY NIGHT THROUGH WEDNESDAY NIGHT...
MOISTURE BELOW 850 MB IN SOUTHEAST WEST VIRGINIA ALTHOUGH MODELS NOT
PRINTING OUT ANY PRECIPITATION. WINDS REMAIN GUSTY UNTIL TUESDAY
MORNING. WINDS AND CLOUDS DIMINISH TUESDAY AFTERNOON AS SURFACE HIGH
PRESSURE BUILDS INTO THE AREA. HAVE A LIMITED AMOUNT OF SNOW SHOWERS
IN WESTERN GREENBRIER COUNTY...BUT CLOUDS WILL HOLD IN LONGER
THROUGH THE MORNING IN THE FAVORED UPSLOPE AREAS.
NEXT SYSTEM REMAINS COMPLEX. STILL MODEL DIFFERENCES IN TIMING AND
EVEN MORE SO IN TEMPERATURE PROFILE. EXPECT BULK OF THE
PRECIPITATION BETWEEN 12Z/7AM WEDNESDAY AND 06Z/1AM THURSDAY. TYPE
AND AMOUNT OF PRECIPITATION WILL BE A CHALLENGE. NAM BUFKIT WAS
SHOWING COLDER TEMPERATURE PROFILES THEN GFS BUFKIT. BEST LOOKING
PART OF THE STORM AT THIS POINT IS THE ISENTROPIC LIFT AND UPSLOPE.
WILL CONTINUE TO HIGHLIGHT THIS SYSTEM IN THE HAZARDOUS WEATHER
OUTLOOK.
&&
.LONG TERM /THURSDAY THROUGH SUNDAY/...
AS OF 230 PM EST SUNDAY...
FROM THURSDAY THROUGH SUNDAY...A LONGWAVE TROUGH IS PROGGED TO BE
OVER THE JAMES BAY REGION OF CANADA AND SOUTH INTO THE EASTERN U.S.
THAT IS ONE ELEMENT OF THIS PORTION OF THE FORECAST THAT HAS
MODERATELY HIGH CONFIDENCE. ANOTHER ELEMENT WITH MODEATELY HIGH
CONFIDENCE IS THE TEMPERATURE FORECAST...AT LEAST THE TREND.
PROGRESSIVELY COLDER AIR WILL BE ENTERING THE REGION ON GUSTY
NORTHWEST WINDS...ESPECIALLY BY THE START OF NEXT WEEKEND. THERE IS
LOW CONFIDENCE CONCERNING THE SPEED AND TRACK OF INDIVIDUAL
SHORTWAVE TROUGHS WITHIN THE LARGER LONGWAVE TROUGH PATTERN.
GUIDANCE COMPARED TO YESTERDAY...AND COMPARED TO EACH OTHER WITH THE
LATEST 12Z...7AM...MODELS...OFFER DIFFERENT SOLUTIONS AND EACH
WOULD IMPACT THE WEATHER ACROSS OUR REGION IN VARIOUS WAYS. GOING
TO LEAN TOWARDS A DRIER...BUT COMPARABLE...SOLUTIION TO THAT
OFFERED FOR THIS TIME PERIOD BY HPC.
GIVEN THIS...OUR FORECAST WILL REFLECT ONE THAT WILL HAVE
PROGRESSIVELY COLDER TEMPERATURES. HIGHS ON THURSDAY WILL BE ROUGHLY
10 TO 15 DEGREE WARMER THAN THOSE EXPECTED ON SUNDAY.
LIKEWISE...LOWS ON THURSDAY NIGHT WILL BE ROUGHLY 10 DEGREES MILDER
THAN THOSE EXPECTED SATURDAY NIGHT. WE WILL HAVE UPSLOPE RAN/SNOW
SHOWERS FORECAST IN SOUTHEAST WEST VIRGINIA AND NEIGHBORING PORTIONS
OF SOUTHWEST VIRGINIA THURSDAY NIGHT AND FRIDAY AS A WEAK SHORTWAVE
TROUGH MOVES THROUGH OHIO VALLEY. BETTER COVERAGE OF PRECIPITATION
IS FORECAST SATURDAY AND SATURDAY NIGHT AHEAD OF..AND DURING THE
PASSAGE OF A SLIGHTLY MORE ROBUST SHORTWAVE TROUGH THAT WILL HAVE
ITS ORIGINS FROM THE CENTRAL PLAINS...AND GET AMPLYFIED AS IT
INTERACTS WITH THE EASTERN LONGWAVE TROUGH. BEHIND THIS
SYSTEM...UPSLOPE SNOW SHOWERS ARE EXPECTED OVER SOUTHEAST WEST
VIRGINIA DURING THE DAY SUNDAY.
&&
.AVIATION /06Z MONDAY THROUGH FRIDAY/...
AS OF 12120 AM EST MONDAY...
INITIAL BATCH OF FAST MOVING PRECIP HAS QUICKLY EXITED TO THE EAST
LEAVING SOME LEFTOVER PATCHY -RA/-DZ IN SPOTS MAINLY OVER THE
WEST. EXPECT MAY SEE SOME ADDED RAIN FILL BACK IN AHEAD OF THE
WARM FRONT BACK OVER TN THROUGH DAYBREAK...OTRW THINKING CIGS
WILL LOWER FROM CURRENT MVFR/VFR LEVELS TO IFR MOST SPOTS AS THE
WARMER AIR ALOFT WORKS OVERTOP THE LINGERING LOW LEVEL WEDGE.
HOWEVER CONFIDENCE RATHER LOW GIVEN MODEL UNCERTAINTY AS
DEVELOPMENT OF MORE RAIN TO THE SW COULD ACTUALLY KEEP CIGS HIGHER
VS THE LOWER DRIZZLE/STRATUS SCENARIO. LOW LEVEL WIND SHEAR WILL
REMAIN A PROBLEM AT MOST LOCATIONS DURING THE OVERNIGHT WITH
STRONG SFC WINDS THE MAIN CONCERN AT KBLF WHERE COULD GUST TO 35
KTS OVER THE NEXT FEW HOURS.
THE LOW LVL WIND SHEAR STARTS TO GO AWAY BY MID MORNING MONDAY AS
THE FRONT MOVES ACROSS AND MIXING TAKES PLACE. THE RAIN/DRIZZLE
SHOULD ALSO START TO EXIT LEAVING BEHIND LOWER CIGS IN ITS WAKE
WITH UPSLOPE SHOWERS OVER SE WV. THE MIXING SHOULD BRING ABOUT
SCATTERING OF LOWER CIGS EAST OF THE WV MTNS BY MIDDAY...WITH
GUSTY WEST-NW WINDS AT 20 TO 35 KNOTS POSSIBLE. WILL HAVE BLF
CLEARING OUT AS WELL AROUND MIDDAY...GIVEN FAST EXIT OF LOW LVL
MOISTURE.
EXPECT VFR TO THEN LINGER INTO MONDAY NIGHT AND TUESDAY WITH HIGH
PRESSURE SPILLING IN FROM THE WEST BEFORE WEAKENING TUESDAY
EVENING.
ANOTHER AREA OF LOW PRESSURE IS THEN EXPECTED TO FORM ON THE
RESIDUAL FRONT TO THE SOUTH BY MIDWEEK WITH PERHAPS ANOTHER ROUND
OF PRECIP AND LOWER CIGS ON WEDNESDAY. VFR SHOULD AGAIN RETURN TO
ALL SITES ON THURSDAY AS WEAK HIGH PRESSURE BUILDS IN BEHIND THE
EXITING AREA OF LOW PRESSURE. THE ARRIVAL OF MUCH COLDER AIR BY
WEEKS END WILL LIKELY PRODUCE A PERIOD OF UPSLOPE MVFR CLDNS FOR
THE SE WVA SITES FRIDAY WITH SCATTERED SNOW SHOWERS POSSIBLE OTRW
VFR ELSW.
&&
.RNK WATCHES/WARNINGS/ADVISORIES...
VA...WIND ADVISORY UNTIL 6 AM EST EARLY THIS MORNING FOR VAZ007-009-
010-015.
NC...WIND ADVISORY UNTIL 6 AM EST EARLY THIS MORNING FOR NCZ001-018.
WV...WIND ADVISORY UNTIL 6 AM EST EARLY THIS MORNING FOR WVZ042.
&&
$$
SYNOPSIS...JH/KK
NEAR TERM...KK/WP
SHORT TERM...AMS/WP
LONG TERM...DS
AVIATION...JH/KK/WP
AREA FORECAST DISCUSSION
NWS SPOKANE WA
217 PM PST Mon Feb 11 2013
.SYNOPSIS...
Moist westerly flow aloft over the region will bring a prolonged
period of occasional light mountain snow and a chance of valley
rain to mainly far eastern Washington and North Idaho tonight
through Thursday. The remainder of the next week will be
seasonably cool with a few minor storm systems bringing light
mountain snow and valley rain or snow mainly on Saturday and again
by late next Monday.
&&
.DISCUSSION...
Tonight through Tuesday: An upper level shortwave trough located at
150W in the Gulf of Alaska will flatten out the ridge of high
pressure protruding over the region off the eastern pacific. We
are already beginning to see some high cloud cover pushing in over
the region as some weak isentropic ascent will continue to develop
at mid to low levels through tonight, especially across the
eastern half of the forecast area with an emphasis in the ID
Panhandle. Isentropic ascent will be weak enough with downsloping
off the Cascades a factor that I don`t think we will see much in
the way of precipitation if any away from the Cascade crest into
the Columbia Basin. Extreme eastern WA and into the Idaho
Panhandle where upslope flow will help generate some more lift
will be the area to watch out for some light snowfall. Best
chances for snow will be late tonight into Wednesday as the
atmosphere moistens from the top down. It will take some time
before snow begins to fall as it will likely evaporate until the
mid level cloud deck lowers enough through the night. We could see
some seeder feeder development as ice crystals fall into the
stratus cloud cover across the valleys in these areas. This would
act to enhance snowfall rates in some areas. However, without much
in the way of any upper level dynamics to support the isentropic
component to this system, I expect snowfall accumulations to be
light overall; but, we could see an inch or two of snowfall over
Lookout Pass by Wednesday afternoon with another inch or two
possible heading over Stevens Pass.
Tuesday night through Wednesday: The shortwave trough over the
Gulf of Alaska will swing through on Tuesday night. This will
result in some better dynamics with a better chance for more
significant snowfall accumulations over the Cascade Crest and over
into the ID Panhandle. Snow levels will be rising and accumulating
snowfall is expected primarily above 3,000 feet with rain in the
valleys. Northwest flow will focus the heaviest snowfall in the
mountains across the Central Panhandle and into the Camas Prairie
by Wednesday. The atmosphere will not be particularly unstable, so
I am not expecting bursts of heavy snowfall accumulations. However,
steady light snowfall could produce up to around 4 to 6 inches
over a 24 hour window Thursday evening through Wednesday evening
above 3,500 feet. This will result in more accumulating snowfall
along I-90 over Lookout Pass.
Winds will be a little breezy, especially up in the mountains as a
surface low develops in the eastern Gulf of Alaska ahead of the
upper level wave and traverses across northern BC and northern Alberta.
Models are now placing the low a bit further north than in
previous runs, so the possibility of stronger winds do not look as
likely. The resulting pressure gradient will generate winds out of
the southwest, which will draw in some warmer air (hence the
rising snow levels). This will also result in temperatures a bit
warmer Tuesday night into Wednesday. /SVH
Wednesday Night and Thursday: Very little changes in the pattern
from the previous periods are expected as a ridge continues to
dominate our weather pattern. With the ridge we will continue to
see the NW flow come over the top of the ridge and across the
region. Continued moisture from Wednesday will bring snowfall to
the Cascade Crests and to the mountains of mainly the Central ID
Panhandle. Valleys in the Central Panhandle will likely see rain
showers or a mix of wet snow and rain. Continued accumulations in
the higher elevations could lead to some decent snow totals
throughout the beginning and middle part of the week. The main
forcing associated with the tail end of this prolonged period of
snow showers looks to be topographical which should keep snow to
mainly lighter intensities.
When dealing with the QPF for these periods the models are in
agreement for the western part of the forecast area but are
struggling with the Panhandle. GFS currently has a much more
significant amount of moisture in the region compared to the drier
ECMWF. Due to the inconsistencies of the GFS I went closer to the
Euro solution with the lighter amount of QPF as this moist flow
starts to exit the region. Towards the end of the period on
Thursday models show a drying trend that will put a stop to most
of snow in the Panhandle as the ridge slowly moves inland and the
moisture stream moves to the east of the forecast area.
Temperatures during these periods become difficult as sky
conditions play a large role as to what we see for highs and
lows. Clearing during the nighttime will allow temps to plummet
whereas clearing in the daytime will allow temps to warm to higher
values than with cloudy skies. With the ridge in place we could
see some clearing making temps a tough call. Based on no major
changes in models kept temps similar to previous forecast and
will have to continue watching trends in cloud cover to help pin
down temps. /Fliehman
Thursday night through Monday...A progressive late winter pattern
with a couple minor precipitation bearing waves and some dry days
is advertised by the latest medium range forecast runs. There is good
agreement between the GFS/ECMWF and Canadian models depicting a
ridge aloft Thursday night through Friday with no compelling
reason to expect anything beyond some late night/early morning
valley and basin fog with seasonably cool temperatures.
Saturday looks like the most active and potentially stormy day of
the extended period with model agreement continuing...and
depicting the approach and passage of a fairly strong but quick
moving upper level trough. Because of the speed of this transient
system...P-type will be dependent on the time of passage...with
an early arrival overnight Friday and Saturday morning bringing
light snow accumulations to much of the region...but if the
arrival is slowed down by 6 or 8 hours to impact the area during
the afternoon then mainly mountain snow with valley/basin rain
showers are more likely. It is too far out to pin the exact timing
down...but confidecne is high that Saturday will feature a weather
producing system.
On Sunday and into Monday the next short wave ridge is expected
with dry and potentially foggy conditions once again...and the
next short wave expected to enter the region on or about late
Monday. Temperatures in this progressive late winter pattern are
likely to remain around seasonal average with no stagnant periods
or sustained advective patterns to allow any appreciable warm-ups
or cool-downs. /Fugazzi
&&
.AVIATION...
18Z TAFS: The western edge of the stratus is following right along the
WA/ID border up to the Spokane/Coeur d`Alene areas and is in much
of the northern valleys. This has resulted in many of the TAF
sites across the region being right on the edge of much of the
stratus. Models are not doing a particularly good job of handling
the boundary layer moisture. HRRR model shows much of the stratus
burning off this afternoon with it having a harder time
redeveloping tonight as mid to high level clouds increase over the
region. Other model guidance shows this stratus remaining over the
region through tomorrow morning. We went with the idea that the
stratus will burn off along its western edge with a FEW-BKN deck
btwn 2.5 to 4 kft agl from KLWS up to KGEG and BKN-OVC deck at
KCOE. This stratus is expected to fill back in toward the west by
this evening, but how much it does may be limited by the higher
cloud cover moving in aloft ahead of the next system for late
tonight into Tuesday. Confidence in stratus coverage is low due to
high model uncertainty. /SVH
&&
.PRELIMINARY POINT TEMPS/POPS...
Spokane 28 39 32 41 27 38 / 0 20 10 20 10 0
Coeur d`Alene 30 38 32 41 27 38 / 20 40 30 20 10 10
Pullman 30 44 35 46 29 41 / 0 30 30 50 30 20
Lewiston 33 48 37 52 34 46 / 0 20 10 30 30 20
Colville 29 39 32 43 27 40 / 10 20 10 10 10 0
Sandpoint 31 38 33 40 27 36 / 40 50 60 20 20 10
Kellogg 30 39 33 43 29 40 / 30 60 80 70 30 20
Moses Lake 29 46 35 49 28 43 / 0 0 0 0 0 0
Wenatchee 30 44 34 47 30 44 / 0 0 0 0 0 0
Omak 23 40 26 40 25 37 / 10 0 10 0 0 0
&&
.OTX WATCHES/WARNINGS/ADVISORIES...
ID...None.
WA...None.
&&
$$
AREA FORECAST DISCUSSION
NWS SPOKANE WA
1008 AM PST Mon Feb 11 2013
.SYNOPSIS...
Dry and seasonably cool conditions will prevail through Monday
with some patchy fog. The next storm system is expected to arrive
on Tuesday bringing light snow mainly to the mountains. The
passage of this storm will bring breezy and gusty conditions to
the mountains Tuesday night. Mainly dry conditions with seasonal
temperatures is expected for the remainder of the week.
&&
.DISCUSSION...
Updated the forecast to decrease cloud cover over much of the
basin and into the Palouse and Camas Prairie. Satellite imagery
this morning is showing much of the stratus banked up in the
northern valleys and Panhandle valleys. Light easterly winds
downsloping off the mountains into the Palouse and L-C Valley
areas has limited the stratus development. Mostly sunny skies are
expected through the afternoon hours today. The stratus should
burn off a bit from the edges this afternoon with some sun breaks
possible late in the afternoon, but mostly cloudy conditions
across the northern valleys and into the Panhandle is expected. A
weak upper level wave passing across the region with some weak
upslope flow into these areas may yield some flurries as well.
High clouds will continue to stream over the region ahead of the
next wave that is expected to begin to move in tonight with a
better chance for some snow, mainly in the Idaho Panhandle and up
along the Cascade crest. /SVH
&&
.AVIATION...
18Z TAFS: The western edge of the stratus is following right along the
WA/ID border up to the Spokane/Coeur d`Alene areas and is in much
of the northern valleys. This has resulted in many of the TAF
sites across the region being right on the edge of much of the
stratus. Models are not doing a particularly good job of handling
the boundary layer moisture. HRRR model shows much of the stratus
burning off this afternoon with it having a harder time
redeveloping tonight as mid to high level clouds increase over the
region. Other model guidance shows this stratus remaining over the
region through tomorrow morning. We went with the idea that the
stratus will burn off along its western edge with a FEW-BKN deck
btwn 2.5 to 4 kft agl from KLWS up to KGEG and BKN-OVC deck at
KCOE. This stratus is expected to fill back in toward the west by
this evening, but how much it does may be limited by the higher
cloud cover moving in aloft ahead of the next system for late
tonight into Tuesday. Confidence in stratus coverage is low due to
high model uncertainty. /SVH
&&
.PRELIMINARY POINT TEMPS/POPS...
Spokane 35 28 39 30 44 26 / 0 0 20 10 20 10
Coeur d`Alene 35 29 38 30 42 26 / 0 10 40 30 20 10
Pullman 38 31 44 34 46 28 / 0 0 30 30 50 20
Lewiston 44 34 48 36 51 33 / 0 0 20 10 30 30
Colville 37 29 39 31 46 26 / 10 10 20 10 10 10
Sandpoint 36 30 38 33 41 26 / 10 20 50 60 20 20
Kellogg 36 29 39 33 42 28 / 10 30 60 70 70 30
Moses Lake 44 29 46 34 48 27 / 0 0 0 0 0 0
Wenatchee 42 30 44 34 47 29 / 0 0 0 0 0 0
Omak 35 24 40 26 42 24 / 0 10 0 10 0 0
&&
.OTX WATCHES/WARNINGS/ADVISORIES...
ID...None.
WA...None.
&&
$$
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
1138 PM CST SUN FEB 10 2013
.SHORT TERM...TONIGHT
829 PM CST SUN FEB 10 2013
WIND ADVISORY TO BE ISSUED SHORTLY...SEE DETAILS BELOW.
THE CORE OF A LOW PRESSURE SYSTEM IS CURRENTLY JUST TO THE WEST OF
THE FORECAST AREA ALONG THE I-35 CORRIDOR IN SOUTH CENTRAL
MINNESOTA. EAST OF THIS LOW...A WARM FRONT EXTENDS TO THE WEST
INTO WESTERN WISCONSIN WITH WIDESPREAD RAIN AND DRIZZLE OCCURRING
ALONG AND TO THE SOUTH OF IT. SOME FOG STILL REMAINS ALONG AND
NORTH OF THIS FRONT...BUT VISIBILITY HAS NOT BEEN BELOW A MILE IN
THIS REGION...SO WILL BE DROPPING THE FOG FROM THE FORECAST. BASED
ON RADAR AND THE LATEST OBSERVATIONS...IT APPEARS THAT THE BACK
EDGE OF THE RAIN/DRIZZLE IS RAPIDLY MOVING TO THE NORTHEAST ACROSS
NORTHEAST IOWA. EXPECT THAT AS THIS BACK EDGE MOVES THROUGH THAT
THERE WILL BE A PERIOD OF DRY CONDITIONS THIS EVENING AND
OVERNIGHT. FURTHER TO THE WEST...MAINLY ALONG AND SOUTH OF THE
SURFACE LOW...PRECIPITATION HAS CHANGED OVER TO SNOW ALONG THE
I-35 CORRIDOR WHERE 11.00Z RAP/LAPS SOUNDINGS INDICATE THAT THE
THERMAL PROFILE HAS COOLED TO ALL BEING BELOW FREEZING. DODGE
COUNTY AND PORTIONS OF SOUTHEAST MINNESOTA MAY GET CLIPPED BY SOME
OF THIS SNOW...BUT IT APPEARS TO MAINLY BE PROPAGATING TO THE
NORTHEAST AND SHOULD NOT DROP MUCH ACROSS THIS REGION.
AS THE LOW MOVES OFF TO THE NORTHEAST...THE COLD FRONT THAT
CURRENTLY EXTENDS TO THE SOUTHEAST OF IT INTO WESTERN IOWA WILL
SWING THROUGH THE REGION AROUND AND SHORTLY AFTER MIDNIGHT. SNOW
SHOWERS WILL MOVE IN AFTER THE FRONT PASSES THOUGH THEY WILL NOT
BE VERY INTENSE. VISIBILITIES HAVE MAINLY BEEN IN THE 1-3SM RANGE
AND THAT IS EXPECTED TO BE THE LOW END OF WHAT WE WILL SEE AS IT
MOVES INTO THE REGION OVERNIGHT INTO TOMORROW.
THE TIGHTENING SURFACE PRESSURE GRADIENT WILL ALSO TRACK TO THE
NORTHEAST WITH THE LOW MOVING IN THAT DIRECTION. THE CORE OF THESE
STRONG WINDS WILL EXTEND ACROSS SOUTHEAST MINNESOTA...NORTHEAST
IOWA AND SOUTHWEST WISCONSIN...PARTICULARLY IN THE HIGHER
ELEVATIONS. 11.00Z AND PREVIOUS RAP BUFKIT SOUNDINGS SHOW THAT
WIND GUSTS SHOULD BE AROUND 45 MPH AT TIMES...PARTICULARLY
TOMORROW MORNING AFTER SUNRISE. WILL BE ISSUING A WIND ADVISORY
STARTING AT MIDNIGHT AND RUNNING IT INTO 3PM TOMORROW AFTERNOON
WHEN IT APPEARS THAT THE WINDS WILL WEAKEN ALONG WITH THE PRESSURE
GRADIENT. THE LOBE OF STRONGEST WINDS WILL START OUT IN THE SOUTH
AND WORK THEIR WAY NORTHWARD AFTER MIDNIGHT...SO SOME LOCATIONS IN
THE ADVISORY MAY BE A LITTLE DELAYED IN GETTING THE STRONGEST
WINDS COMPARED TO THAT AREA.
.LONG TERM...WEDNESDAY THROUGH SUNDAY
256 PM CST SUN FEB 10 2013
NORTHWEST FLOW ALOFT WILL SET UP OVER THE UPPER MIDWEST IN THE
WAKE OF THE CURRENT STORM SYSTEM. THIS WILL ALLOW A SYSTEM TO DROP
INTO THE REGION FOR THE MIDDLE OR END OF THE WEEK. THE MODELS SHOW
VERY LITTLE CONSISTENCY ON THE TIMING OF THIS FEATURE. THE 10.12Z
GFS IS THE FASTEST BRINGING IN WEDNESDAY AFTERNOON WHILE THE
10.12Z GEM IS THE SLOWEST AND STRONGEST AND DOES NOT BRING IT IN
UNTIL THURSDAY NIGHT. UNTIL THESE TIMING DIFFERENCES ARE WORKED
OUT...WILL NEED TO CARRY A MENTION OF PRECIPITATION FROM WEDNESDAY
NIGHT THROUGH FRIDAY WITH THE BEST CHANCES CENTERED ON WEDNESDAY
NIGHT AND THURSDAY. THE SURFACE LOW MAY PASS BY JUST TO THE NORTH
OF THE AREA THURSDAY BRINGING ENOUGH WARM AIR FOR A MIX OF RAIN
AND SNOW ACROSS THE SOUTH WITH LIGHT SNOW EXPECTED ELSEWHERE.
&&
.AVIATION...THROUGH 06Z TUESDAY
1138 PM CST SUN FEB 10 2013
PRECIPITATION IS CHANGING OVER TO SNOW AS A COLD FRONT APPROACHES
THE REGION. CONDITIONS ARE EXPECTED TO BE MAINLY AT IFR OR LOWER
THROUGHOUT THE REGION THOUGH LSE HAS BEEN AT LOW END MVFR WITH A
1100FT CEILING. CEILINGS WILL LIKELY BE MORE STABLE THAN WHAT
VISIBILITIES ARE AS THE SNOW IS FAIRLY VARIABLE WITH CONDITIONS
RANGING FROM 6SM DOWN TO 1 1/2SM AT TIMES AS THE SNOW SHOWERS
COMES THROUGH. EXPECT THAT THIS WILL BE THE CASE THROUGH MUCH OF
THE MORNING AND EARLY AFTERNOON HOURS BEFORE THE FORCING WEAKENS
LATE IN THE AFTERNOON. WINDS WILL INCREASE AS THE COLD FRONT MOVES
THROUGH THE REGION TONIGHT WITH SUSTAINED WINDS AROUND 20 TO 25KTS
WITH GUSTS UP TO 35-37KTS AT TIMES. THESE WEST TO NORTHWEST WINDS
WILL DIMINISH IN SPEED LATE IN THE AFTERNOON AND EVENING HOURS AS
THE SURFACE LOW ASSOCIATED WITH THIS SYSTEM TRACKS FURTHER TO THE
NORTHEAST.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
829 PM CST SUN FEB 10 2013
WI...WIND ADVISORY FROM MIDNIGHT TONIGHT TO 3 PM CST MONDAY FOR
WIZ032>034-041>044-053>055-061.
MN...WIND ADVISORY FROM MIDNIGHT TONIGHT TO 3 PM CST MONDAY FOR
MNZ079-086>088-094>096.
IA...WIND ADVISORY FROM MIDNIGHT TONIGHT TO 3 PM CST MONDAY FOR
IAZ008>011-018-019-029-030.
&&
$$
SHORT TERM...HALBACH
LONG TERM...04
AVIATION...HALBACH
AREA FORECAST DISCUSSION...UPDATED
NWS MILWAUKEE/SULLIVAN WI
1030 PM CST SUN FEB 10 2013
.UPDATE...
ISSUED A WIND ADVISORY FOR THE ENTIRE CWA FOR OVERNIGHT INTO
MONDAY. POINTS AGAINST ISSUING WITH AN 06Z START TIME ARE: THE
INVERSION OVER THE SNOW-PACK PREVENTING FULL MOMENTUM TRANSFER TO
THE SURFACE TONIGHT. USUAL DIFFICULTY IN GETTING SUSTAINED 30 MPH WINDS
WITH THE ROUGH TERRAIN...TREES...HILLS...ETC.
POINTS FOR ARE THE 40 TO 44 KNOT WINDS JUST OFF THE SURFACE ABOVE
A WEAK NEAR-SURFACE INVERSION. ONCE COLD AIR ADVECTION BEGINS WITH
4 TO 6 MB PER 3 HOUR SURFACE PRESSURE RISES...THIS INVERSION DISAPPEARS
AND THERE IS A GOOD POTENTIAL OF A 40 KNOT GUST TO REACH THE
SURFACE. 36KT GUST AT MONROE REPORTED AT 0335Z SHOWS HOW EASILY AN
ADVISORY LEVEL GUST COULD REACH THE SURFACE.
REALIZE IT WILL BE MARGINAL OVER THE NORTHEAST AS GRADIENT WONT BE
AS TIGHT UNTIL LATER IN THE OVERNIGHT...BUT NEW NAM FORECAST SOUNDINGS FOR
SHEBOYGAN IN LINE WITH RAP SHOWING MIXING UP TO 40-41 KTS BY
08Z...SO AN ISOLATED ADVISORY LEVEL GUST NOT OUT OF THE QUESTION.
BETTER CHANCE FOR WIDESPREAD ADVISORY CONDITIONS MONDAY...WITH
MIXING UP TO 875 MB AND WEST TO NORTHWEST WINDS AROUND 40 KTS.
&&
.AVIATION/06Z TAFS/...
WILL TAKE OUT LOW-LEVEL WIND SHEAR AS DIFFERENTIAL DECREASES WITH
INCREASING SURFACE WIND GUSTS. VFR CONDITIONS OVER THE FORECAST
AREA ARE TEMPORARY AND WILL DROP BACK TO MVFR BY ISSUANCE TIME.
WIND GUSTS WILL BE THE MAIN ISSUE AS SOUTHWEST WINDS WILL INCREASE
TO 20 TO 25 KT SUSTAINED...WITH GUSTS OF 30 TO 40 KTS...BECOMING WEST
IN THE MORNING WITH GUSTS TO 45 KNOTS BY LATE IN THE MORNING INTO
THE AFTERNOON. WINDS WILL SLOWLY DECREASE FROM SOUTHWEST TO
NORTHEAST DURING THE AFTERNOON AND EVENING...BUT ENOUGH GRADIENT
FOR GUSTS TO AT LEAST 20 KNOTS AT KMSN AND KUES THROUGH 06Z
TUESDAY...AND AROUND 25 KNOTS AT KENW AND KMKE.
WILL SEE LAST BAND OF LIQUID PCPN PUSH OUT OVER LAKE MICHIGAN
AROUND/SHORTLY AFTER 06Z...WITH POCKETS OF LIGHT SNOW SHOWERS OR
FLURRIES ROTATING THROUGH THE FORECAST AREA OVERNIGHT AND MONDAY
WITH VORTICITY MAXIMA SPINNING AROUND CLOSED 500 MB LOW. WILL KEEP
MVFR CIGS THROUGH THE REMAINDER OF THE FORECAST...THOUGH SOME IFR
POSSIBLE IN THE SNOW SHOWERS.
&&
.MARINE...
ADJUSTED START TIME OF GALE WARNING TO 06Z...THOUGH FREQUENT GALE
GUSTS BECOME MORE LIKELY CLOSER TO 08Z...THE POTENTIAL FOR GALE
GUSTS WITH THE EARLY WIND GUST TO 35 KNOTS AT MONROE AND
COLLABORATION SUPPORTED THE 06Z START. WILL NEED A SMALL CRAFT
ADVISORY AFTER GALE WARNING EXPIRES...THOUGH LATEST DATA SUGGESTS
GALE WARNING MAY NEED AND EXTENSION OVER THE THE NORTHERN ZONES.
WAVES WILL BEGIN TO SUBSIDE MONDAY MORNING WITH REDUCED FETCH AS
WINDS TURN WEST.
&&
.PREV DISCUSSION... /ISSUED 340 PM CST SUN FEB 10 2013/
VERY SHORT TERM...TONIGHT AND MONDAY.
RAIN WILL WIND DOWN THROUGH LATE AFTERNOON. COULD SEE A QUICK ROUND
OF SHOWERS SLIDE THROUGH EARLY EVENING WITH SHORTWAVE.
OTHERWISE...WILL SEE SOME DRIZZLE AND FOG AT TIMES THROUGH LATE
EVENING.
COLD FRONT WILL HEAD THROUGH THE FORECAST AREA LATE EVENING INTO
TONIGHT...WITH SNOW SHOWERS LIKELY DEVELOPING BEHIND THE FRONT. BEST
CHANCE FOR SNOW SHOWERS LOOKS TO BE LATE TONIGHT THROUGH TOMORROW
MORNING AS MAIN SHORTWAVE PUSHES THROUGH. EXPECTING MOST EVERYWHERE
SHOULD SEE SHOW SHOWERS...WITH A DUSTING TO A COUPLE TENTHS OF AN
INCH POSSIBLE...THE HIGHEST AMOUNTS ACROSS THE NORTHERN FORECAST
AREA. SNOW SHOWERS WILL LIKELY WIND DOWN TOMORROW AFTERNOON.
OTHER THING OF NOTE WILL BE INCREASING WINDS BEHIND THE COLD FRONT
LATE TONIGHT INTO MONDAY. GUSTS OF 35 TO 40 MPH EXPECTED MOST PLACES
FROM MID MORNING MONDAY THROUGH MUCH OF THE DAYTIME HOURS. HIGHEST
GUSTS WILL BE IN THE SOUTHEAST WHERE THEY COULD APPROACH WIND
ADVISORY LEVELS OF 45 MPH.
SHORT TERM...MONDAY NIGHT THROUGH WEDNESDAY.
UPPER LOW PULLS AWAY FROM THE WESTERN GREAT LAKES A BIT FASTER LATER
MONDAY AND MONDAY NIGHT AS MID LEVELS RAPIDLY DRY. HENCE WL LOWER
POPS BUT STILL MAY BE ABLE TO SQUEEZE OUT SOME EVENING FLURRIES FROM
LINGERING LOW LEVEL RH AND CYCLONIC CURVATURE. OTHERWISE A DRY
PERIOD CAN BE EXPECTED AS SOUTHERN WISCONSIN REMAINS IN DRIER
WEST-NORTHWEST FLOW WITH PASSING WEAK HIGH PRESSURE ON TUESDAY AND
WEDNESDAY. SPLIT CONTINUES THROUGH THIS PERIOD WITH SOUTHERN STREAM
REMAINING ACTIVE OVER SOUTHERN CONUS. VERY WEAK RIPPLES CAUGHT IN
THE FAST FLOW MAY BRING SEVERAL PERIODS OF CLOUDS TO THE AREA ON TUE
AND WED. HOWEVER TEMPERATURES SHOULD AVERAGE CLOSE TO SEASONAL
NORMAL.
LONG TERM...WEDNESDAY NIGHT THROUGH SUNDAY.
INCREASINGLY HIGHER AMPLITUDE UPSTREAM RIDGE OVER THE EASTERN
PACIFIC RESULTS IN DEEPING LONG WAVE TROFING DOWNSTREAM OVER
CENTRAL/EASTERN CONUS EARLY IN THE PERIOD. MEDIUM RANGE GUIDANCE
GETTING INTO BETTER AGREEMENT ON CLIPPER-TYPE SYSTEM MOVING
SOUTHEAST ALONG THE LEADING EDGE OF THE SURGE OF COLDER AIR AND
AFFECTING SOUTHERN WI PERHAPS AS EARLY AS WEDNESDAY NIGHT. HENCE
CONFIDENCE INCREASING ON A PERIOD OF -SN AFFECTING SOUTHERN WI
AROUND THURSDAY WITH ACCUMULATIONS. CIPS 24 HOUR ANALOGS CENTERED AT
00Z/15 HAS A LOW PROBABILITY OF SNOWFALL EXCEEDING 2 INCHES AT THIS
TIME. CONSIDERING THIS WAVE IS TRAVELING ALONG A TIGHTENING
BAROCLINIC ZONE...WOULD NOT BE SURPRISED IF FUTURE GUIDANCE SHOWS
FURTHER STRENGTHENING OF THIS SYSTEM. WILL TREND UPWARD IN POPS FOR
THU AND SURROUNDING PERIODS. ENSEMBLE MEMBERS COMING INTO BETTER
AGREEMENT AS WELL ON DEEPENING SHORT WAVE TROUGH OVER WESTERN
GTLAKES ON THU.
COLDER AIR THEN EXPECTED TO SETTLE OVER THE REGION ON FRIDAY AND
LINGER THROUGH THE WEEKEND. BOTH UKMO AND ECMWF INDICATING ANOTHER
CLIPPER SYSTEM SLIDING SOUTHEAST ACROSS THE UPPER MIDWEST AND
POSSIBLY AFFECTING PORTIONS OF WI OVER THE WEEKEND. HOWEVER
CONFIDENCE IN THIS LAST SYSTEM REMAINS LOW.
AVIATION /00Z TAFS/...
RAIN WILL WIND DOWN THROUGH LATE AFTERNOON. COULD SEE A QUICK ROUND
OF SHOWERS SLIDE THROUGH EARLY EVENING WITH SHORTWAVE.
OTHERWISE...WILL SEE SOME DRIZZLE AND FOG AT TIMES THROUGH LATE
EVENING. CIGS AND VSBYS WILL STAY ON THE LOW SIDE THROUGH THE
EVENING AHEAD OF AN APPROACHING COLD FRONT.
THE COLD FRONT WILL HEAD THROUGH THE FORECAST AREA LATE EVENING INTO
TONIGHT...WITH SNOW SHOWERS LIKELY DEVELOPING BEHIND THE FRONT. BEST
CHANCE FOR SNOW SHOWERS LOOKS TO BE LATE TONIGHT THROUGH TOMORROW
MORNING AS MAIN SHORTWAVE PUSHES THROUGH. EXPECTING MOST EVERYWHERE
SHOULD SEE SHOW SHOWERS...WITH A DUSTING TO A COUPLE TENTHS OF AN
INCH POSSIBLE...THE HIGHEST AMOUNTS ACROSS THE NORTHERN FORECAST
AREA. SNOW SHOWERS WILL LIKELY WIND DOWN TOMORROW AFTERNOON. VSBYS
WILL IMPROVE OVERALL AS THE COLDER AIR FILTERS IN...THOUGH TEMPORARY
LOWER VSBYS POSSIBLE IN ANY SNOW SHOWERS. CIGS WILL IMPROVE
ALSO...THOUGH LIKELY REMAINING MVFR THROUGH THE DAY MONDAY.
MARINE...
UPGRADED THE GALE WATCH TO A WARNING...STARTING IT VERY LATE TONIGHT
AND RUNNING THROUGH THE DAY MONDAY. SMALL CRAFT ADVISORY REMAINS IN
EFFECT UNTIL THE GALE WARNING GOES INTO EFFECT. LOOKS LIKE A GOOD
SHOT FOR GUSTS OF 35 KNOTS DURING THE WARNING PERIOD...POSSIBLY AS
HIGH AS 40 KNOTS.
WAVES WILL STAY HIGH INTO TONIGHT...SLOWLY SUBSIDING LATE TONIGHT
AND MONDAY AS WINDS BECOME OFFSHORE.
MAY NEED A SMALL CRAFT ADVISORY FOR AT LEAST MONDAY EVENING AFTER
THE GALE ENDS...AS WINDS WILL SLOWLY EASE THROUGH THE EVENING AND
OVERNIGHT.
&&
.MKX WATCHES/WARNINGS/ADVISORIES...
WI...WIND ADVISORY UNTIL 3 PM CST MONDAY FOR WIZ046-047-051-052-
056>060-062>072.
LM...SMALL CRAFT ADVISORY UNTIL MIDNIGHT CST TONIGHT FOR LMZ643>646.
GALE WARNING UNTIL 6 PM CST MONDAY FOR LMZ643>646.
&&
$$
UPDATE...REM
TONIGHT/MONDAY AND AVIATION/MARINE...DDV
MONDAY NIGHT THROUGH SUNDAY...MBK
AREA FORECAST DISCUSSION
NWS TAMPA BAY RUSKIN FL
430 AM EST WED FEB 13 2013
.SYNOPSIS...
09Z WATER VAPOR AND H4 RAP ANALYSIS SHOWING AN UPPER LEVEL PATTERN
CONSISTING OF BROAD RIDGING ALONG THE PACIFIC COAST FOLLOWED
DOWNSTREAM BY BROAD LONGWAVE TROUGHING ACROSS THE CENTRAL PORTION OF
THE COUNTRY. A STRONGER IMPULSE/SHORTWAVE IS EMBEDDED WITHIN THIS
TROUGH OVER THE CENTRAL/SOUTHERN PLAINS AND IS NOW QUICKLY EJECTING
EASTWARD TOWARD THE TN VALLEY AND SOUTHEASTERN STATES. OUR LOCAL
AREA RESIDES WITHIN A ZONES OF DEEP SOUTHWEST TO NORTHEAST MOISTURE
TRANSPORT BETWEEN THIS LONGWAVE TROUGH...AND A BROAD RIDGE OVER
THE WESTERN CARIBBEAN/FL STRAITS.
AT THE SURFACE...FL PENINSULA RESIDES WITH THE WARM SECTOR BETWEEN A
SYNOPTIC LOW OVER SOUTHERN AL...AND A SURFACE RIDGE ACROSS THE FL
STRAITS. SURFACE WARM FRONT EXTENDS EASTWARD FROM THE LOW ACROSS
SOUTHERN GA EARLY THIS MORNING WITH A TRAILING COLD FRONT MOVING
EASTWARD ACROSS THE CENTRAL GULF OF MEXICO. THIS FRONT WILL ARRIVE
OVER OUR REGION LATER TODAY AND TONIGHT. SEEING QUITE A BIT OF LOW
CLOUDS AND PATCHY FOG THIS MORNING WITHIN THE DEEP SOUTHERLY
MOISTURE TRANSPORT. THE BIGGEST CONCENTRATION OF THESE LOWER CLOUDS
IS COMING OFF THE GULF AS THE HIGHER DEWPOINT AIR INTERACTS WITH THE
COOLER SHELF WATERS...ESPECIALLY FROM WEST OF TAMPA BAY UP ALONG THE
NATURE COAST. DIFFICULT TO DETERMINE IF WE ARE DEALING WITH LOWER
STRATUS OR FOG OUT OF THE MARINE AREA...AS WE HAVE NOT SEEN MUCH
VISIBILITY REDUCTIONS AT ANY OF THE COASTAL STATIONS. IF
VERIFICATION ARRIVES THAT VISIBILITIES ARE SIGNIFICANTLY REDUCED
OVER THE MARINE AREA...THEN A DENSE FOG ADVISORY MAY BECOME
NECESSARY LATER THIS MORNING. REGIONAL RADARS SHOWS SHOWERS AND
STORM ONGOING ACROSS THE FL PANHANDLE/WESTERN BIG BEND WITHIN A
BROAD SWATH OF LOW LEVEL MOISTURE TRANSPORT/THETA-E ADVECTION.
&&
.SHORT TERM (TODAY THROUGH FRIDAY)...
TODAY/TONIGHT...
STRONG MID-LEVEL SHORTWAVE AND ASSOCIATED SURFACE LOW WILL PASS TO
OUR NORTH THROUGH THIS EVENING WHILE A COLD FRONT TRAILING SOUTH
FROM THE LOW APPROACHES FROM THE EASTERN GULF OF MEXICO. BROAD
SYNOPTIC FORCING ASSOCIATED WITH THE PASSING ENERGY ALONG WITH THE
LOW LEVEL FORCING AHEAD OF THE FRONT WILL BE ENOUGH TO SUPPORT A
BAND OF SHOWERS AND STORMS. THIS BAND IS FORECAST TO SHIFT SOUTH
AND SOUTHEAST WITH TIME FROM THE NATURE COAST LATER THIS MORNING AND
AFTERNOON....THROUGH THE TAMPA BAY/I-4 CORRIDOR DURING THE AFTERNOON
AND EARLY EVENING...AND THEN FURTHER SOUTH LATE IN THE DAY/EVENING.
LOW LEVEL WAA REGION/THETA-E ADVECTION AHEAD OF THE FRONT LOOKS TO
SLOWLY DIMINISH THROUGH THE DAY...ALONG WITH AN EVENTUAL WEAKENING
OF THE OVERALL KINEMATICS. WITH ALL THIS IN MIND...THE MOST
ORGANIZED BAND OF CONVECTION SHOULD OCCUR AS THE ACTIVITY IS
CROSSING THE NORTHERN AND CENTRAL PORTION OF THE FORECAST
AREA...WITH WEAKER AND MORE BROKEN CONVECTION ACROSS THE SOUTH. POPS
WILL FOLLOW TODAY WITH LIKELY TO CATEGORICAL VALUES NORTH AND THEN
DECREASING TO CHANCE/SLIGHT CHANCE POPS SOUTH AND SOUTHEAST FROM
TAMPA BAY. WILL CONTINUE TO MONITOR THE CHANCE OF A FEW STRONGER
STORMS...ACROSS THE NATURE COAST THROUGH THE EARLY AFTERNOON WITH
ISOLATED STRONG WIND GUSTS THE MAIN THREAT WITH ANY OF THE MORE
VIGOROUS CELLS. DEPARTING LOW LEVEL JET SHOULD FURTHER DECREASE ANY
WIND THREAT BY LATER IN THE DAY. A SLOW COOL DOWN BEGIN OVERNIGHT AS
WINDS SHIFT TO THE NORTH BEHIND THE FRONT. BROAD RESIDUAL SYNOPTIC
FLOW AND PLENTY OF LEFTOVER COLUMN MOISTURE MAY STILL SQUEEZE OUT A
FEW SHOWERS...BUT COVERAGE AND INTENSITY WILL BE LOW.
THURSDAY THROUGH FRIDAY...
LOWER CONFIDENCE FORECAST THAN NORMAL FOR THE SHORT TERM PERIOD WHEN
IT COMES TO THE DETAILS FOR THE FINAL TWO DAYS OF THE WORK WEEK. THE
REGION WILL BE LEFT WITHIN A BROAD CYCLONIC FLOW THAT WILL FEATURE
OCCASIONAL WEAKER IMPULSES PASSING THROUGH. THE COMBINATION OF THE
PERIODIC SYNOPTIC SUPPORT ASSOCIATED WITH THESE IMPULSES AND SEVERAL
FAVORABLE UPPER JET PLACEMENTS WILL FAVOR OFF AND ON PERIOD OF
COOL SHOWERS/RAIN. CERTAINLY NOT LOOKING FOR RAIN ALL THE TIME...BUT
WHEN THE INGREDIENTS COME TOGETHER WE CAN EXPECT SEVERAL SURGES
OF SHOWERS TO CROSS THE PENINSULA. IT IS THE EXACTLY WHERE AND WHEN
THAT MAKE THIS FORECAST DIFFICULT. VARYING SOLUTIONS ARE POSED BY
THE VARIOUS GUIDANCE MEMBERS...ALL SHOWING THIS OFF AND ON
ACTIVITY...BUT WITH UNIQUE PATTERNS. OVERALL IT IS THE I-4
CORRIDOR AND SOUTHWARD THE WOULD SEEM TO BE IN LINE TO EXPERIENCE
THE MOST SHOWER ACTIVITY...BUT WILL KEEP CHANCE POPS GOING FURTHER
NORTH TO ACCOUNT FOR THE FORECAST UNCERTAINTY. TEMPERATURES WILL BE
COOLER THAN PREVIOUS DAYS...ESPECIALLY WHERE THE RAIN PATTERNS
EVENTUALLY SET UP. DRIER AIR FILTERING IN FROM THE NORTH IN THE
LOWER LEVELS WOULD COMBINE WITH THE RAIN TO PRODUCE POTENTIAL
WET-BULB EFFECT. HAVE GONE WITH A BLEND OF THE WARMER MAV AND COOLER
MET TEMPERATURES TO BEGIN THE TREND TOWARD POTENTIALLY COOLER END OF
THE WEEK TEMPS.
&&
.LONG TERM (FRIDAY NIGHT THROUGH NEXT TUESDAY)...
ALL MODELS SHOW A DEEPENING UPPER-LEVEL TROUGH SWINGING THROUGH THE
REGION OVER THE WEEKEND. THE GFS AND CANADIAN MODELS SHOW A MORE
PROGRESSIVE NATURE TO THE TROUGH WITH THE AXIS MOVING ACROSS THE
STATE SATURDAY NIGHT. THE ECMWF IS LAGGING BEHIND BY 12 TO 18 HOURS.
IN GENERAL...MODELS ARE FASTER NOW WITH THE TROUGH AND COLD AIR MASS
WHICH IN TURN MEANS THE COLD AIR WILL MOVE OUT NEARLY AS FAST AS IT
COMES IN.
LINGERING SHOWERS OVER OUR SOUTHERN ZONES FRIDAY NIGHT SHOULD COME
TO AN END BY SATURDAY MORNING FOLLOWED BY MUCH COOLER AIR AND
INCREASING NORTHWESTERLY WINDS. GENERALLY FOLLOWED LATEST MEX
GUIDANCE WHICH SHOWS TEMPERATURES HOLDING IN THE MIDDLE 60S EXCEPT
FOR OUR FAR SOUTHERN ZONES WHERE WE COULD STILL SEE SOME LOWER 70S.
WITH THE COLD AIR MASS COMING IN FASTER...IT NOW LOOKS LIKE OUR
COLDEST NIGHT WILL BE SATURDAY NIGHT...ALTHOUGH SUNDAY NIGHT COULD
STILL BE QUITE CHILLY. THE FASTER SOLUTION MEANS THE COLD HIGH
CENTER MOVES OUT INTO THE ATLANTIC MORE QUICKLY RESULTING IN A
RETURN FLOW FROM THE EAST. IT STILL LOOKS LIKE WE WILL SEE FREEZING
TEMPERATURES NORTH OF TAMPA BAY...BUT ON SUNDAY MORNING RATHER THAN
MONDAY MORNING.
SUNDAY SHOULD BE SUNNY AND COOL WITH WINDS SLOWLY DIMINISHING. HIGHS
WILL STAY IN THE 60S. SUNDAY NIGHT WILL BE COLD AGAIN...BUT DO NOT
EXPECT WIDESPREAD FREEZING TEMPERATURES ANYWHERE.
THE COLD HIGH WILL MOVE INTO THE ATLANTIC BY MONDAY PROVIDING A
RATHER QUICK WARMUP DURING THE DAY. HIGHS WILL BE ABOUT 8 DEGREES
WARMER THAN ON SUNDAY. BY TUESDAY...WE ARE BACK INTO THE MIDDLE 70S
TO NEAR 80...BUT A COLD FRONT WILL BE APPROACHING FROM THE NORTHWEST
SO THERE WILL BE A SLIGHT CHANCE OF SHOWERS NORTH OF TAMPA. THE
FRONT ON TUESDAY LOOKS LIKE ANOTHER MESSY ONE WITH RAIN CHANCES
EXTENDING INTO THE MIDDLE OF THE WEEK.
&&
.MARINE...
CAUTIONARY LEVEL WINDS OUT OF THE SOUTH WILL CONTINUE TODAY AHEAD OF
AN APPROACHING COLD FRONT. AREAS OF MARINE FOG WILL ALSO CONTINUE
ACROSS AREAS MAINLY OFFSHORE AND TO THE NORTH OF TAMPA BAY. THE COLD
FRONT WILL CROSS THE FORECAST WATERS THIS AFTERNOON AND THIS EVENING
WITH A WIND SHIFT TO THE NORTH IN ITS WAKE. WINDS WILL REMAIN FROM A
NORTHERLY DIRECTION THROUGH AT LEAST THE EARLY PORTION OF THE
UPCOMING WEEKEND AS HIGH PRESSURE SLOWLY BUILDS EAST TOWARD THE
REGION.
&&
.AVIATION...
AREAS OF LOW CLOUDS AND SOME FOG CONTINUE TO PLAGUE MOST OF THE TAF
SITES THIS MORNING. THERE ARE GAPS IN THE COVERAGE WHICH LEADS TO
PERIODS OF VFR CONDITIONS BETWEEN THE IFR TO EVEN LIFR CEILINGS.
VERY LOW CONFIDENCE IN THE FORECASTS FOR THE NEXT 24 HOURS...BUT IN
GENERAL LOOK FOR IMPROVING CONDITIONS BY LATE MORNING WITH MAINLY
MVFR CEILINGS. SOME SHOWERS AND STORMS WILL PRECEDE A FRONT LATER
THIS AFTERNOON.
&&
.FIRE WEATHER...
RELATIVE HUMIDITY VALUES WILL REMAIN WELL ABOVE CRITICAL LEVELS
TODAY AHEAD OF A COLD FRONT...HOWEVER GUSTY SOUTHWEST WINDS AND GOOD
DISPERSION INDICES CAN BE EXPECTED. SOME LOW LEVEL DRY AIR WILL
ATTEMPT TO FILTER IN FROM THE NORTH THE NEXT COUPLE OF DAYS BEHIND
THE FRONT...BUT THE PATTERN WILL SUPPORT A CONTINUED CHANCE OF
SHOWERS...AN NO CRITICAL LEVELS OF RELATIVE HUMIDITY ARE ANTICIPATED
THROUGH FRIDAY. UNLIKE TODAY...DISPERSION INDICES WILL BE QUITE LOW
FOR THURSDAY AND FRIDAY...LIKELY REMAINING BELOW 30 FOR MOST
LOCATIONS.
&&
.PRELIMINARY POINT TEMPS/POPS...
TPA 80 60 71 55 / 60 40 30 60
FMY 85 64 80 60 / 20 30 60 60
GIF 83 57 74 52 / 50 40 30 60
SRQ 78 59 73 58 / 50 40 40 60
BKV 80 54 71 48 / 70 30 20 60
SPG 80 61 71 58 / 60 40 30 60
&&
.TBW WATCHES/WARNINGS/ADVISORIES...
FL...BEACH HAZARDS STATEMENT THROUGH THURSDAY EVENING FOR
CHARLOTTE-LEE.
LAKE WIND ADVISORY FROM 10 AM THIS MORNING TO 6 PM EST
THIS EVENING FOR CHARLOTTE-CITRUS-DESOTO-HARDEE-
HERNANDO-HIGHLANDS-HILLSBOROUGH-LEE-LEVY-MANATEE-
PASCO-PINELLAS-POLK-SARASOTA-SUMTER.
BEACH HAZARDS STATEMENT THROUGH THIS EVENING FOR SARASOTA.
GULF WATERS...NONE.
&&
$$
SYNOPSIS/SHORT TERM/MARINE/FIRE WX...MROCZKA
LONG TERM/AVIATION...JILLSON
AREA FORECAST DISCUSSION
NWS CHARLESTON SC
153 AM EST WED FEB 13 2013
.SYNOPSIS...
A WARM FRONT WILL LIFT NORTH THROUGH THE REGION THIS MORNING
AS LOW PRESSURE PASSES TO THE WEST. A COLD FRONT WILL SWEEP
THROUGH THE AREA LATE TODAY...WITH HIGH PRESSURE EXPECTED TO
BUILD ACROSS THE REGION THURSDAY INTO EARLY SATURDAY. ANOTHER COLD
FRONT WILL PUSH THROUGH THE AREA SATURDAY...FOLLOWED BY STRONGER
HIGH PRESSURE AND COOLER CONDITIONS INTO EARLY NEXT WEEK.
&&
.NEAR TERM /UNTIL 6 AM THIS MORNING/...
EARLY WEDNESDAY MORNING SURFACE ANALYSIS REMAINED COMPLEX AS THE
WARM FRONT HAD ADVANCED TO AROUND ALTAMAHA SOUND...AHEAD OF A
SURFACE LOW CENTERED BETWEEN AMG AND JES. THIS LOW AND ASSOCIATED
WIDESPREAD PRECIPITATION CONTINUED TO DELAY THE NORTHWARD
PROGRESS OF THE WARM FRONT ACROSS SOUTHERN GEORGIA. NORTH OF THE
WARM FRONT... WIDESPREAD RAINS OCCASIONALLY PUNCTUATED BY ELEVATED
THUNDERSTORMS CONTINUED WITHIN BREAD SWATH OF DEEP LAYER
ASCENT/MOISTURE FLOWING ACROSS THE REGION FROM S/SW TO E/NE.
MODELS DOING A REASONABLE JOB WITH RAIN DEPICTION BUT MAY STRUGGLE
OVERNIGHT WITH THE DETAIL OF THE WARM FRONTAL PROGRESSION GIVEN
THE PRESENCE OF THE SURFACE LOW OVER SE GA AND COMPLICATED SURFACE
LAYERED STABILITY PROFILES. TEMPS WERE IN THE MID 50S MOST AREAS
AS NEAR SATURATION EVIDENT ON SOUNDING PROFILES. OVERNIGHT...A
FAIRLY UNSTABLE MID LEVEL ENVIRONMENT WILL SPREAD OVER THE
FORECAST REGION BUT GIVEN THE CURRENT RADAR TRENDS AND A MORE
BELIEVABLE RUC FORECAST...THE POTENTIAL FOR SEVERE WEATHER
OVERNIGHT DOES NOT APPEAR TOO IMPRESSIVE DESPITE INCREASING SHEAR
PROFILES. EVEN ACROSS FAR SOUTHERN COUNTIES/CLOSER TO THE WARM
FRONT WHERE THUNDERSTORMS WILL REMAIN MOST COMMON...THE POTENTIAL
FOR ISOLATED SEVERE WEATHER WILL BE SOMEWHAT GREATER BUT STILL
LIMITED DUE TO IMPACTS OF ONGOING/WIDESPREAD PRECIP ON SURFACE
BASED INSTABILITY.
CATEGORICAL POPS REMAIN IN ORDER OVERNIGHT. FORECASTS CONTINUE TO
INDICATE ONLY SLOWLY WARMING TEMPS WHERE RAINS WERE STEADIER AND
HEAVIER. THE BEST CHANCE FOR TEMPS RISING THROUGH THE 60S LATE
SHOULD BE TO THE S OF I-16.
&&
.SHORT TERM /6 AM THIS MORNING THROUGH FRIDAY/...
WEDNESDAY...A STRONG SHORTWAVE TROUGH CURRENTLY OVER THE SOUTHERN
PLAINS WILL STEADILY SHIFT EAST EARLY WEDNESDAY...BECOMING MORE
STRETCHED/SHEARED AS IT MOVES INTO THE TENNESSEE/LOWER MISSISSIPPI
VALLEYS BY MIDDAY. THIS UPPER LEVEL ENERGY WILL SUPPORT THE
DEVELOPMENT OF A SURFACE LOW LIFTING FROM THE GULF COAST STATES INTO
THE UPSTATE CAROLINAS AS THE DAY PROGRESSES. NUMERICAL MODELS ARE IN
DECENT AGREEMENT THAT THE ASSOCIATED WARM FRONT WILL BE LOCATED
RIGHT ALONG THE NORTHERN BORDER OF THE FORECAST AREA...PERHAPS
AROUND THE SANTEE RIVER...BY DAYBREAK WEDNESDAY. AS A
RESULT...TEMPERATURES WILL RISE WELL ABOVE SEASONAL NORMALS INTO THE
UPPER 60S NORTH TO LOWER 70S SOUTH.
BOTH 12Z NAM AND 12Z GFS SOLUTIONS INDICATE LOW TO MODERATE
INSTABILITY INCREASING ACROSS MUCH OF THE FORECAST AREA THROUGH
THE MORNING AND AFTERNOON HOURS...WITH CAPE VALUES POSSIBLY
REACHING 1000 J/KG OVER THE CHARLESTON TRI COUNTY REGION BY 18Z.
THE SOUTHEAST STATES WILL BE IN THE VICINITY OF THE RIGHT REAR
OF A 100 KT 500 MB JET AND A 30 TO 40 KT LOW LEVEL JET. THE
COMBINATION OF MODERATELY FAVORABLE INSTABILITY AND DECENT SHEAR
SUGGESTS ISOLATED TO SCATTERED THUNDERSTORMS ARE POSSIBLE...WITH
A FEW THUNDERSTORMS POTENTIALLY BECOMING STRONG AND ORGANIZED.
STORM PREDICTION CENTER HAS PLACED THE SOUTHERN HALF OF THE
FORECAST AREA...WHERE TEMPERATURES AND DEWPOINTS WILL BE
HIGHEST...WITHIN A SLIGHT RISK FOR SEVERE THUNDERSTORM
DEVELOPMENT. WILL ADD MENTION OF ISOLATED STORMS POSSIBLY
BECOMING SEVERE IN THE HAZARDOUS WEATHER OUTLOOK. IT SHOULD BE
NOTED THAT THICK CLOUD COVER AND MARGINAL LAPSE RATES COULD
NEGATIVELY IMPACT STORM ORGANIZATION...AND MUCH UNCERTAINTY IN
THUNDERSTORM STRENGTH AND COVERAGE REMAINS.
WEDNESDAY NIGHT...AS THE SURFACE LOW CONTINUES TO LIFT
NORTH/NORTHEAST TOWARD THE MID ATLANTIC COASTLINE...A TRAILING
COLD FRONT WILL PULL THROUGH THE FORECAST AREA BY THE EVENING
HOURS. SHOWER AND THUNDERSTORM CHANCES WILL THUS END FAIRLY
QUICKLY FROM WEST TO EAST BETWEEN 00Z AND 06Z WEDNESDAY
NIGHT...WITH DRIER DEEP LAYER AIR MOVING IN BEHIND THE DEPARTING
FRONT. COLD ADVECTION OVERNIGHT WILL ALLOW TEMPERATURES TO FALL
INTO THE UPPER 30S INLAND TO THE LOWER 40S NEAR THE COAST.
THURSDAY AND FRIDAY...WEAK SURFACE HIGH PRESSURE WILL BUILD INTO THE
REGION AND SET UP PREVAILING WEST/NORTHWEST SYNOPTIC FLOW. EXPECT
DRY CONDITIONS AND SLIGHTLY COOLER TEMPERATURES...WITH HIGHS
GENERALLY REACHING THE MID 60S THURSDAY AND THE MID TO UPPER 60S
FRIDAY. LOW TEMPERATURES THURSDAY NIGHT WILL REFLECT IMPROVED
RADIATIONAL COOLING CONDITIONS UNDER CLEAR SKIES AND LIGHTER
WINDS...RANGING FROM THE MID TO UPPER 30S INLAND TO THE LOWER 40S
NEAR THE COAST.
&&
.LONG TERM /FRIDAY NIGHT THROUGH TUESDAY/...
AN ARCTIC FRONT WILL PUSH THROUGH THE SOUTHEAST STATES LATE
SATURDAY AHEAD OF A SHARP UPPER TROUGH DIVING TOWARD THE AREA FROM
THE GREAT LAKES/CENTRAL PLAINS REGION. THERE IS SOME EVIDENCE IN
MEDIUM RANGE MODEL SOLUTIONS OF ISOLATED RAIN ASSOCIATED WITH THE
UPPER TROUGH PROGRESSION TO SUPPORT SLIGHT CHANCE POPS FOR THE
NORTHERN HALF OF THE AREA SATURDAY NIGHT. GUIDANCE IS STILL
SHOWING HIGHS IN THE UPPER 50S TO LOWER 60S AHEAD OF THE FRONT ON
SATURDAY...BUT SUSPECT TEMPERATURES WILL BE FALLING DURING THE
AFTERNOON DEPENDING ON THE EXACT TIMING OF THE FRONT. THERE IS
SOME CONCERN ABOUT THE POTENTIAL FOR SOME BRIEF WINTRY PRECIP
WITH THIS FRONT...AS MODELS DROP 850MB TEMPS TO -2 TO -4C BY 00Z
SUNDAY. HOWEVER...BOUNDARY LATER TEMPS COULD BE TOO WARM. PREFER
TO CONTINUE MONITORING MODEL TRENDS FOR THIS PERIOD.
THE DEEP ARCTIC UPPER TROUGH PUSHES OFFSHORE INTO THE ATLANTIC
SUNDAY...THEN ZONAL FLOW TO SLIGHT RIDGING BUILDS BACK INTO THE
UPPER LEVELS FOR MONDAY. BELOW CLIMO TEMPS EXPECTED FOR SUNDAY AND
MONDAY WITH HIGHS IN THE 50S...AS WELL AS THE POTENTIAL FOR
FREEZING OVERNIGHT/EARLY MORNING TEMPS...ESPECIALLY MONDAY
MORNING. EXPECT MODERATING TEMPS BY TUESDAY AS MODELS SHOW
ANOTHER STRONG UPPER TROUGH AND ASSOCIATED SURFACE FRONT MOVING
TOWARD THE REGION. DUE TO UNCERTAINTY IN THE TIMING OF THIS
FEATURE...HAVE GONE WITH SLIGHT CHANCE TO CHANCE POPS.
&&
.AVIATION /07Z WEDNESDAY THROUGH SUNDAY/...
THE 06Z TAF PACKAGE ENCOMPASSES A COMPLEX PERIOD. INITIALLY...
WIDESPREAD RAIN NORTH OF A WARM FRONT WILL BE HEAVY AT TIMES AND
WILL BE ACCOMPANIED BY FLIGHT CONDITIONS RANGING FROM MVFR TO
LIFR. ELEVATED THUNDERSTORMS COULD IMPACT KSAV AND KCHS AT ANY
TIME THROUGH THIS MORNING. HOWEVER...PRECISE TIMING WILL REMAIN
DIFFICULT AND HAVE OPTED TO ISSUE AMENDMENTS AS REQUIRED TO
ADDRESS NEAR TERM CONVECTIVE TRENDS.
MAINTAINED LOW LEVEL WIND SHEAR TO ACCOUNT FOR SW WINDS AROUND 40
KT JUST ABOVE THE SURFACE OVERNIGHT INTO WEDNESDAY MORNING.
NORTHWARD PROGRESS OF THE WARM FRONT WILL TURN WINDS TO THE S/SW
AND SHOULD EVENTUALLY USHER IMPROVING CEILINGS/VISIBILITY LATER
THIS MORNING...AND PREVAILING VFR CONDITIONS SHOULD DEVELOP BY
LATE MORNING/EARLY AFTERNOON. HOWEVER...ADDITIONAL
SHOWERS/THUNDERSTORMS WILL DEVELOP AHEAD OF AN ADVANCING COLD
FRONT...AND THIS PRECIPITATION COULD IMPACT TERMINALS WITH BRIEF
FLIGHT RESTRICTIONS UNTIL LATE AFTERNOON. THUNDERSTORMS COULD
ACCOMPANY COLD FROPA AT BOTH TERMINALS...BUT A SLIGHTLY BETTER
CHANCE FOR THUNDERSTORMS SHOULD FOCUS AROUND KSAV.
THIS EVENING...POST COLD FROPA CONDITIONS SHOULD RETURN TO VFR
WITH NO ADDITIONAL FLIGHT RESTRICTIONS EXPECTED.
EXTENDED AVIATION OUTLOOK...MAINLY VFR THROUGH THE WEEKEND.
&&
.MARINE...
A WARM FRONT AND ASSOCIATED LOW LEVEL JETTING/INCREASING SOUTHERLY
FLOW HAD ADVANCED INTO GA WATERS AND WILL CONTINUE TO ADVANCE
NORTH THROUGH SC WATERS OVERNIGHT. SOME GUSTS TO 25 KT WILL
OCCUR ACROSS THE OFFSHORE GA WATERS. ELSEWHERE IT WILL BE CLOSER
TO DAYBREAK WEDNESDAY WHEN THE WINDS BECOME MORE GUSTY. WE HAVE
THE SMALL CRAFT ADVISORY FOR OFFSHORE GA WATERS TONIGHT.
WEDNESDAY THROUGH SUNDAY...SMALL CRAFT ADVISORY CONDITIONS WILL
BE ONGOING FOR MUCH OF THE MARINE AREA WEDNESDAY...AS A SURFACE
LOW PASSES WELL NORTHWEST OF THE WATERS AND A COLD FRONT CROSSES
OFFSHORE DURING THE EVENING HOURS. EXPECT WINDS AND SEAS TO
GRADUALLY FALL BELOW ADVISORY LEVELS LATE WEDNESDAY NIGHT INTO
THURSDAY MORNING...WITH HIGH PRESSURE BUILDING OVER THE REGION
FROM THE WEST. A STRONGER COLD FRONT AND HIGH PRESSURE IS EXPECTED
TO SUPPORT ANOTHER SURGE IN WINDS TO ADVISORY LEVELS LATER
SATURDAY AND SATURDAY NIGHT. THERE IS EVEN THE POTENTIAL FOR SOME
MARGINAL GALE CONDITIONS SATURDAY NIGHT...HOWEVER UNCERTAINTY IS TOO
HIGH TO MENTION AT THIS POINT. WINDS AND SEAS WILL BE GRADUALLY
FALLING BACK BELOW HIGHLIGHTS SUNDAY...AS HIGH PRESSURE BUILDS
OVER THE REGION AGAIN.
&&
.HYDROLOGY...
LOCALLY HEAVY RAIN WILL CONTINUE OVERNIGHT...AND PERIODS OF
DROUGHT-RELIEVING RAINS TO CONTINUE THROUGH WEDNESDAY. STORM TOTAL
RAINFALL AMOUNTS OF 2-4 INCHES WILL BE SPREAD OVER A LONG ENOUGH
PERIOD TO PRECLUDE WIDESPREAD FLASH FLOOD ISSUES... BUT SEVERAL OF
OUR RIVERS ARE EXPECTED TO APPROACH FLOOD STAGE LATER IN THE WEEK.
&&
.CHS WATCHES/WARNINGS/ADVISORIES...
GA...NONE.
SC...NONE.
MARINE...SMALL CRAFT ADVISORY FROM 6 AM THIS MORNING TO 10 PM EST THIS
EVENING FOR AMZ352.
SMALL CRAFT ADVISORY UNTIL 5 AM EST THURSDAY FOR AMZ374.
SMALL CRAFT ADVISORY FROM 6 AM THIS MORNING TO 5 AM EST
THURSDAY FOR AMZ350.
&&
$$
SYNOPSIS...
NEAR TERM...SPR
SHORT TERM...79
LONG TERM...RFM
AVIATION...SPR
MARINE...SPR
HYDROLOGY...
AREA FORECAST DISCUSSION
NWS CHARLESTON SC
1258 AM EST WED FEB 13 2013
.SYNOPSIS...
A STATIONARY FRONT OVER FAR SOUTH GEORGIA WILL LIFT NORTH INTO THE
AREA AS A WARM FRONT LATE TONIGHT...WHILE GULF LOW PRESSURE PASSES
TO THE WEST. A COLD FRONT WILL SWEEP THROUGH THE AREA LATE WEDNESDAY...
WITH HIGH PRESSURE EXPECTED TO BUILD ACROSS THE REGION THURSDAY INTO
EARLY SATURDAY. ANOTHER COLD FRONT WILL PUSH THROUGH THE AREA
SATURDAY...FOLLOWED BY STRONGER HIGH PRESSURE AND COOLER CONDITIONS
INTO EARLY NEXT WEEK.
&&
.NEAR TERM /UNTIL 6 AM THIS MORNING/...
EARLY MORNING SURFACE ANALYSIS REMAINED COMPLEX AS THE WARM FRONT
HAS ADVANCED TO AROUND ALTAMAHA SOUND...AHEAD OF A SURFACE LOW
CENTERED NEAR AMG. THIS LOW AND ASSOCIATED WIDESPREAD
PRECIPITATION HAD THUS FAR DELAYED THE NORTHWARD PROGRESS OF THE
WARM FRONT ACROSS SOUTHERN GEORGIA. NORTH OF THE WARM FRONT...
WIDESPREAD RAINS OCCASIONALLY PUNCTUATED BY ELEVATED THUNDERSTORMS
CONTINUED WITHIN BREAD SWATH OF DEEP LAYER ASCENT/MOISTURE FLOWING
ACROSS THE REGION FROM S/SW TO E/NE.
MODELS DOING A REASONABLE JOB WITH RAIN DEPICTION BUT MAY STRUGGLE
OVERNIGHT WITH THE DETAIL OF THE WARM FRONTAL PROGRESSION GIVEN
THE PRESENCE OF THE SURFACE LOW OVER SE GA AND COMPLICATED SURFACE
LAYERED STABILITY PROFILES. TEMPS WERE IN THE MID 50S MOST AREAS
AS NEAR SATURATION EVIDENT ON SOUNDING PROFILES. OVERNIGHT...A
FAIRLY UNSTABLE MID LEVEL ENVIRONMENT WILL SPREAD OVER THE
FORECAST REGION BUT GIVEN THE CURRENT RADAR TRENDS AND A MORE
BELIEVABLE RUC FORECAST...THE POTENTIAL FOR SEVERE WEATHER
OVERNIGHT DOES NOT APPEAR TOO IMPRESSIVE DESPITE INCREASING SHEAR
PROFILES. EVEN ACROSS FAR SOUTHERN COUNTIES/CLOSER TO THE WARM
FRONT WHERE THUNDERSTORMS WILL REMAIN MOST COMMON...THE POTENTIAL
FOR ISOLATED SEVERE WEATHER WILL BE SOMEWHAT GREATER BUT STILL
LIMITED DUE TO IMPACTS OF ONGOING/WIDESPREAD PRECIP ON SURFACE
BASED INSTABILITY.
CATEGORICAL POPS REMAIN IN ORDER OVERNIGHT. FORECASTS CONTINUE TO
INDICATE ONLY SLOWLY WARMING TEMPS WHERE RAINS WERE STEADIER AND
HEAVIER. THE BEST CHANCE FOR TEMPS RISING THROUGH THE 60S LATE
SHOULD BE TO THE S OF I-16.
&&
.SHORT TERM /6 AM THIS MORNING THROUGH FRIDAY/...
WEDNESDAY...A STRONG SHORTWAVE TROUGH CURRENTLY OVER THE SOUTHERN
PLAINS WILL STEADILY SHIFT EAST EARLY WEDNESDAY...BECOMING MORE
STRETCHED/SHEARED AS IT MOVES INTO THE TENNESSEE/LOWER MISSISSIPPI
VALLEYS BY MIDDAY. THIS UPPER LEVEL ENERGY WILL SUPPORT THE
DEVELOPMENT OF A SURFACE LOW LIFTING FROM THE GULF COAST STATES INTO
THE UPSTATE CAROLINAS AS THE DAY PROGRESSES. NUMERICAL MODELS ARE IN
DECENT AGREEMENT THAT THE ASSOCIATED WARM FRONT WILL BE LOCATED
RIGHT ALONG THE NORTHERN BORDER OF THE FORECAST AREA...PERHAPS
AROUND THE SANTEE RIVER...BY DAYBREAK WEDNESDAY. AS A
RESULT...TEMPERATURES WILL RISE WELL ABOVE SEASONAL NORMALS INTO THE
UPPER 60S NORTH TO LOWER 70S SOUTH.
BOTH 12Z NAM AND 12Z GFS SOLUTIONS INDICATE LOW TO MODERATE
INSTABILITY INCREASING ACROSS MUCH OF THE FORECAST AREA THROUGH
THE MORNING AND AFTERNOON HOURS...WITH CAPE VALUES POSSIBLY
REACHING 1000 J/KG OVER THE CHARLESTON TRI COUNTY REGION BY 18Z.
THE SOUTHEAST STATES WILL BE IN THE VICINITY OF THE RIGHT REAR
OF A 100 KT 500 MB JET AND A 30 TO 40 KT LOW LEVEL JET. THE
COMBINATION OF MODERATELY FAVORABLE INSTABILITY AND DECENT SHEAR
SUGGESTS ISOLATED TO SCATTERED THUNDERSTORMS ARE POSSIBLE...WITH
A FEW THUNDERSTORMS POTENTIALLY BECOMING STRONG AND ORGANIZED.
STORM PREDICTION CENTER HAS PLACED THE SOUTHERN HALF OF THE
FORECAST AREA...WHERE TEMPERATURES AND DEWPOINTS WILL BE
HIGHEST...WITHIN A SLIGHT RISK FOR SEVERE THUNDERSTORM
DEVELOPMENT. WILL ADD MENTION OF ISOLATED STORMS POSSIBLY
BECOMING SEVERE IN THE HAZARDOUS WEATHER OUTLOOK. IT SHOULD BE
NOTED THAT THICK CLOUD COVER AND MARGINAL LAPSE RATES COULD
NEGATIVELY IMPACT STORM ORGANIZATION...AND MUCH UNCERTAINTY IN
THUNDERSTORM STRENGTH AND COVERAGE REMAINS.
WEDNESDAY NIGHT...AS THE SURFACE LOW CONTINUES TO LIFT
NORTH/NORTHEAST TOWARD THE MID ATLANTIC COASTLINE...A TRAILING
COLD FRONT WILL PULL THROUGH THE FORECAST AREA BY THE EVENING
HOURS. SHOWER AND THUNDERSTORM CHANCES WILL THUS END FAIRLY
QUICKLY FROM WEST TO EAST BETWEEN 00Z AND 06Z WEDNESDAY
NIGHT...WITH DRIER DEEP LAYER AIR MOVING IN BEHIND THE DEPARTING
FRONT. COLD ADVECTION OVERNIGHT WILL ALLOW TEMPERATURES TO FALL
INTO THE UPPER 30S INLAND TO THE LOWER 40S NEAR THE COAST.
THURSDAY AND FRIDAY...WEAK SURFACE HIGH PRESSURE WILL BUILD INTO THE
REGION AND SET UP PREVAILING WEST/NORTHWEST SYNOPTIC FLOW. EXPECT
DRY CONDITIONS AND SLIGHTLY COOLER TEMPERATURES...WITH HIGHS
GENERALLY REACHING THE MID 60S THURSDAY AND THE MID TO UPPER 60S
FRIDAY. LOW TEMPERATURES THURSDAY NIGHT WILL REFLECT IMPROVED
RADIATIONAL COOLING CONDITIONS UNDER CLEAR SKIES AND LIGHTER
WINDS...RANGING FROM THE MID TO UPPER 30S INLAND TO THE LOWER 40S
NEAR THE COAST.
&&
.LONG TERM /FRIDAY NIGHT THROUGH TUESDAY/...
AN ARCTIC FRONT WILL PUSH THROUGH THE SOUTHEAST STATES LATE
SATURDAY AHEAD OF A SHARP UPPER TROUGH DIVING TOWARD THE AREA FROM
THE GREAT LAKES/CENTRAL PLAINS REGION. THERE IS SOME EVIDENCE IN
MEDIUM RANGE MODEL SOLUTIONS OF ISOLATED RAIN ASSOCIATED WITH THE
UPPER TROUGH PROGRESSION TO SUPPORT SLIGHT CHANCE POPS FOR THE
NORTHERN HALF OF THE AREA SATURDAY NIGHT. GUIDANCE IS STILL
SHOWING HIGHS IN THE UPPER 50S TO LOWER 60S AHEAD OF THE FRONT ON
SATURDAY...BUT SUSPECT TEMPERATURES WILL BE FALLING DURING THE
AFTERNOON DEPENDING ON THE EXACT TIMING OF THE FRONT. THERE IS
SOME CONCERN ABOUT THE POTENTIAL FOR SOME BRIEF WINTRY PRECIP
WITH THIS FRONT...AS MODELS DROP 850MB TEMPS TO -2 TO -4C BY 00Z
SUNDAY. HOWEVER...BOUNDARY LATER TEMPS COULD BE TOO WARM. PREFER
TO CONTINUE MONITORING MODEL TRENDS FOR THIS PERIOD.
THE DEEP ARCTIC UPPER TROUGH PUSHES OFFSHORE INTO THE ATLANTIC
SUNDAY...THEN ZONAL FLOW TO SLIGHT RIDGING BUILDS BACK INTO THE
UPPER LEVELS FOR MONDAY. BELOW CLIMO TEMPS EXPECTED FOR SUNDAY AND
MONDAY WITH HIGHS IN THE 50S...AS WELL AS THE POTENTIAL FOR
FREEZING OVERNIGHT/EARLY MORNING TEMPS...ESPECIALLY MONDAY
MORNING. EXPECT MODERATING TEMPS BY TUESDAY AS MODELS SHOW
ANOTHER STRONG UPPER TROUGH AND ASSOCIATED SURFACE FRONT MOVING
TOWARD THE REGION. DUE TO UNCERTAINTY IN THE TIMING OF THIS
FEATURE...HAVE GONE WITH SLIGHT CHANCE TO CHANCE POPS.
&&
.AVIATION /06Z WEDNESDAY THROUGH SUNDAY/...
THE 06Z TAF PACKAGE ENCOMPASSES A COMPLEX PERIOD. INITIALLY...
WIDESPREAD RAIN NORTH OF A WARM FRONT WILL BE HEAVY AT TIMES AND
WILL BE ACCOMPANIED BY FLIGHT CONDITIONS RANGING FROM MVFR TO
LIFR. ELEVATED THUNDERSTORMS COULD IMPACT KSAV AND KCHS AT ANY
TIME THROUGH THIS MORNING. HOWEVER...PRECISE TIMING WILL REMAIN
DIFFICULT AND HAVE OPTED TO ISSUE AMENDMENTS AS REQUIRED TO
ADDRESS NEAR TERM CONVECTIVE TRENDS.
MAINTAINED LOW LEVEL WIND SHEAR TO ACCOUNT FOR SW WINDS AROUND 40
KT JUST ABOVE THE SURFACE OVERNIGHT INTO WEDNESDAY MORNING.
NORTHWARD PROGRESS OF THE WARM FRONT WILL TURN WINDS TO THE S/SW
AND SHOULD EVENTUALLY USHER IMPROVING CEILINGS/VISIBILITY LATER
THIS MORNING...AND PREVAILING VFR CONDITIONS SHOULD DEVELOP BY
LATE MORNING/EARLY AFTERNOON. HOWEVER...ADDITIONAL
SHOWERS/THUNDERSTORMS WILL DEVELOP AHEAD OF AN ADVANCING COLD
FRONT...AND THIS PRECIPITATION COULD IMPACT TERMINALS WITH BRIEF
FLIGHT RESTRICTIONS UNTIL LATE AFTERNOON. THUNDERSTORMS COULD
ACCOMPANY COLD FROPA AT BOTH TERMINALS...BUT A SLIGHTLY BETTER
CHANCE FOR THUNDERSTORMS SHOULD FOCUS AROUND KSAV.
THIS EVENING...POST COLD FROPA CONDITIONS SHOULD RETURN TO VFR
WITH NO ADDITIONAL FLIGHT RESTRICTIONS EXPECTED.
EXTENDED AVIATION OUTLOOK...MAINLY VFR THROUGH THE WEEKEND.
&&
.MARINE...
A WARM FRONT AND ASSOCIATED LOW LEVEL JETTING/INCREASING SOUTHERLY
FLOW HAD ADVANCED INTO GA WATERS AND WILL CONTINUE TO ADVANCE
NORTH THROUGH SC WATERS OVERNIGHT. SOME GUSTS TO 25 KT WILL
OCCUR ACROSS THE OFFSHORE GA WATERS. ELSEWHERE IT WILL BE CLOSER
TO DAYBREAK WEDNESDAY WHEN THE WINDS BECOME MORE GUSTY. WE HAVE
THE SMALL CRAFT ADVISORY FOR OFFSHORE GA WATERS TONIGHT.
WEDNESDAY THROUGH SUNDAY...SMALL CRAFT ADVISORY CONDITIONS WILL
BE ONGOING FOR MUCH OF THE MARINE AREA WEDNESDAY...AS A SURFACE
LOW PASSES WELL NORTHWEST OF THE WATERS AND A COLD FRONT CROSSES
OFFSHORE DURING THE EVENING HOURS. EXPECT WINDS AND SEAS TO
GRADUALLY FALL BELOW ADVISORY LEVELS LATE WEDNESDAY NIGHT INTO
THURSDAY MORNING...WITH HIGH PRESSURE BUILDING OVER THE REGION
FROM THE WEST. A STRONGER COLD FRONT AND HIGH PRESSURE IS EXPECTED
TO SUPPORT ANOTHER SURGE IN WINDS TO ADVISORY LEVELS LATER
SATURDAY AND SATURDAY NIGHT. THERE IS EVEN THE POTENTIAL FOR SOME
MARGINAL GALE CONDITIONS SATURDAY NIGHT...HOWEVER UNCERTAINTY IS TOO
HIGH TO MENTION AT THIS POINT. WINDS AND SEAS WILL BE GRADUALLY
FALLING BACK BELOW HIGHLIGHTS SUNDAY...AS HIGH PRESSURE BUILDS
OVER THE REGION AGAIN.
&&
.HYDROLOGY...
LOCALLY HEAVY RAIN WILL CONTINUE OVERNIGHT...AND PERIODS OF
DROUGHT-RELIEVING RAINS TO CONTINUE THROUGH WEDNESDAY. STORM TOTAL
RAINFALL AMOUNTS OF 2-4 INCHES WILL BE SPREAD OVER A LONG ENOUGH
PERIOD TO PRECLUDE WIDESPREAD FLASH FLOOD ISSUES... BUT SEVERAL OF
OUR RIVERS ARE EXPECTED TO APPROACH FLOOD STAGE LATER IN THE WEEK.
&&
.CHS WATCHES/WARNINGS/ADVISORIES...
GA...NONE.
SC...NONE.
MARINE...SMALL CRAFT ADVISORY FROM 6 AM THIS MORNING TO 10 PM EST THIS
EVENING FOR AMZ352.
SMALL CRAFT ADVISORY UNTIL 5 AM EST THURSDAY FOR AMZ374.
SMALL CRAFT ADVISORY FROM 6 AM THIS MORNING TO 5 AM EST
THURSDAY FOR AMZ350.
&&
$$
SYNOPSIS...
NEAR TERM...SPR
SHORT TERM...79
LONG TERM...RFM
AVIATION...SPR
MARINE...SPR
HYDROLOGY...
AREA FORECAST DISCUSSION
NWS NORTHERN INDIANA
117 AM EST WED FEB 13 2013
.AVIATION...
WARM AIR ADVECTION WAS INCREASING OVER THE WESTERN GREAT LAKES
REGION. A RECEDING SC CLOUD BANK WAS OVER LOWER MICHIGAN AND
EXTENDED INTO NRN INDIANA. HAVE MADE SOME MINOR ADJUSTMENTS IN THE
SCATTERING OUT OF THIS CLOUD LAYER. OTHERWISE...CONDITIONS WILL
BECOME VFR EARLY IN THE TAF PERIOD AND SHOULD PERSIST AS THE LOW
LEVEL FLOW REMAINS FROM THE WEST IN A RELATIVELY DRY AIRMASS.
&&
.PREV DISCUSSION... /ISSUED 307 PM EST TUE FEB 12 2013/
SHORT TERM... SFC RIDGING INVOF OF OH RVR WILL BREAK DOWN INADV
OF SW CLIPPER DROPPING OUT OF SWRN CANADA WED AFTN. HWVR NO
SENSIBLE WX OF CONSEQUENCE XPCD WITHIN THIS EVOLUTION THROUGH THIS
PD. MIXING/EROSION OF SC CLD DECK ONGOING THIS AFTN W/PARTIAL
SUNSHINE NOW ACRS MUCH OF ERN HALF CWA BUT WRN FLANK EXTENDING
BACK INTO NE IL HOLDING TOUGH AND MAY POSE A BUST OVERNIGHT WRT
MIN TEMPS. ATTM SHRT TERM RUC GIVES A NOD TWD PRIOR EVEN MOS
BLEND. OTRWS AT LEAST PARTIAL INSOLATION XPCD AGAIN ON WED W/STGR
DIURNAL WITHIN MODEST LL SWRLY FLW. IN FACT MOS MAX TEMP SPLIT
ESSENTIALLY EVEN AND REFLECTED IN GRIDDED MAXS.
LONG TERM... /THURSDAY THROUGH TUESDAY/
ACTIVE PATTERN IN STORE FOR THE LONG TERM PERIOD. ONE MORE DAY OF
ABOVE NORMAL TEMPS ON TAP FOR THURSDAY AHEAD OF SHOT OF ARCTIC AIR
DROPPING SE ACROSS THE PLAINS. STRONG FORCING ALONG THE FRONT WILL
STIR UP AT LEAST A CHC FOR RAIN OR SNOW SHOWERS BUT OVERALL QPF
APPEARS MINIMAL AT THIS POINT. POPS STILL HELD IN CHC/SCHC RANGE
FOR NOW. GREATER FOCUS THEN TURNS TOWARDS LAKE EFFECT POTENTIAL
AS STG NW FLOW SETS UP WITH SFC-850 MB DELTA T`S PUSHING 20 C AND
SFC-700 MB DELTA T`S PUSHING UPR 20S. NAM/WRF SHOW A PERIOD OF
FAVORABLE COLLOCATION OF DGZ AND TOP OF STRONG OMEGA. INVERSION
HGTS BEGIN TO CLIMB...ESPECIALLY DURING THE DAY FRIDAY WHEN SOME
ADDITIONAL SYNOPTIC MSTR ARRIVES AND A REINFORCING SHOT OF COLD
AIR. HAVE TENDED TO FOCUS GREATEST POPS FRIDAY TO MATCH WITH THE
ABOVE SETUP. ACCUMS AT THIS POINT APPEAR TO BE ON THE LIGHTER SIDE
BUT WILL NEED TO BE WATCHED IN COMING FORECASTS. WHILE AN
OUTLIER...SEVERAL RUNS OF THE GEM NHEM MODEL HAVE BEEN SHOWING
PHASING OF N/S STREAM SYSTEMS SOONER THAN LATER WITH A STORM
AFFECTING THE GREAT LAKES VS EAST COAST. ECMWF/GFS DO NOT PHASES
THE ENERGY UNTIL REACHING EAST COAST SO AT THIS POINT HAVE TO PUT
IT ON THE BACK BURNER BUT WILL NEED TO WATCH. LAKE EFFECT WILL
LINGER POTENTIALLY THROUGH MUCH OF THE WEEKEND WITH CONTINUED NW
FLOW AND 850 MB RIDGING STILL TO THE WEST UNTIL LATE SUNDAY. NEXT
SYSTEM TO FOCUS ON WILL BE WHAT LOOKS LIKE A PANHANDLE HOOK COMING
TOWARDS THE REGION MONDAY NIGHT INTO TUESDAY. SIGNALS POINT
TOWARDS MEASURABLE PRECIP FOR PARTS OF THE AREA BUT EXACT TRACK
AND AMOUNT OF COLD AIR REMAIN QUESTIONABLE THIS FAR OUT IN THE
FORECAST. HAVE WENT WITH MID-HIGH END CHC POPS WITH MIX OF RAIN OR
SNOW WITH LIKELY REFINEMENT OF FORECAST TO COME OVER THE NEXT
SEVERAL DAYS.
&&
.IWX WATCHES/WARNINGS/ADVISORIES...
IN...NONE.
MI...NONE.
OH...NONE.
LM...NONE.
&&
$$
SHORT TERM...T
LONG TERM...FISHER
AVIATION...SKIPPER
AREA FORECAST DISCUSSION
NWS JACKSON KY
422 AM EST WED FEB 13 2013
.SHORT TERM...(TODAY THROUGH THURSDAY)
ISSUED AT 423 AM EST WED FEB 13 2013
CURRENT 09Z ANALYSIS ACROSS THE AREA HAS WIDESPREAD CLOUD COVER OVER
EASTERN KENTUCKY WITH PRECIP ALONG THE TN AND KY BORDER IN SOUTH
CENTRAL KY DEVELOPING AND MOVING INTO THE AREA. CURRENT TEMPERATURES
ACROSS THE SOUTHERN PORTION OF THE AREA ARE IN THE LOW 40S TO UPPER
30S. HOWEVER SURFACE TEMPS ALONG AND NORTH OF THE MOUNTAIN PARKWAY
ARE COLD ENOUGH TO SUSTAIN SOME SNOWFALL AS THE PRECIP WILL CREEP
INTO THE NORTHERN PORTION OF THE CWA BY 12Z. MET SAT DATA CURRENTLY
SHOWS THE DEVELOPING SURFACE LOW OVER THE LOWER TN VALLEY AND
SHIFTING OFF TO THE NORTHEAST. THE UPPER LOW IS LOCATED OVER SOUTHERN
IL MOVING TO THE EAST NORTHEAST. CURRENT SHORT TERM MODELS INDICATE A
BAND OF HEAVY PRECIP SETTING UP. THE CHALLENGE HERE IS THE LOCATION
OF THE DEVELOPMENT. BOTH THE NAM AND GFS HAVE INDICATED A BAND OF
HEAVIER PRECIP JUST SOUTH OF THE OH RIVER AND ALSO ANOTHER BAND
GOING THROUGH CENTRAL EASTERN KY. THE HI RES HRRR ALSO SHOWS THIS BUT
WITH THE SOUTHERN BAND NOT AS INTENSE. BASED ON CURRENT WV SHOWING
MID LEVEL MOISTURE AND ADVECTING TOWARD THE UPPER OH VALLEY...HAVE
GONE WITH THE BLUEGRASS AND LOCATIONS NORTH OF THE MOUNTAIN PARKWAY TO
RECEIVE UP TO AN INCH OF SNOWFALL. CURRENT THOUGH IS WITH THE
SOUTHEAST KY STILL QUITE WARMER THAN THE NORTH LOCATIONS...THE BAND
INDICATED THROUGH THE CENTRAL PORTION OF EAST KY...WILL MAINLY BE A
RAIN PRODUCER WITH THE BEST CHANCE FOR ACCUMULATING SNOW ION THE
HIGHER TERRAIN ALONG THE VA BORDER. AS WELL...NAM MODEL SOUNDINGS
STILL SHOW A POOR DENDRITE GROWTH ZONE THROUGH MUCH OF THE
EVENT...LOCATED FROM THE JKL POINT AND SOUTH.
BASED ON ALL THESE FACTORS...HAVE KEPT THE SPS GOING WITH THE INCH
POSSIBLE NORTH OF THE MOUNTAIN PARKWAY AND IN THE HIGHER TERRAIN
ALONG THE VA BORDER. IF THE BAND IN THE NORTH DOES SLIDE SOUTH A
BIT...THE BLUE GRASS COUNTIES WILL QUICKLY REACH ADVISORY CRITERIA.
FOR THE REST OF THE SHORT TERM...A PROGRESSIVE PATTERN REMAINS...SUCH
THAT...LOCATIONS THAT FINALLY BECOME COLD ENOUGH TO SUPPORT SNOW THIS
EVENING AND TONIGHT...MUCH OF THE MOISTURE WILL BE OUT OF THE AREA
WITH A FEW FLURRIES POSSIBLE. THE PATTERN WILL ALLOW A BRIEF STAY FOR
THIS COLDER AIR MASS AS THURSDAY HIGH TEMPS WILL QUICKLY WARM INTO
THE UPPER 40S...MELTING ANY SNOW THAT FALLS TODAY AND TONIGHT.
.LONG TERM...(THURSDAY NIGHT THROUGH TUESDAY)
ISSUED AT 341 AM EST WED FEB 13 2013
THE MODEL START OFF IN FAIRLY GOOD AGREEMENT WITH AN UPPER TROUGH
EXTENDING ACROSS THE MIDWEST. THIS UPPER TROUGH WILL PUSH A WEAK
FRONT ACROSS THE AREA ON FRIDAY BRINGING INITIALLY A MIX OF RAIN AND
SNOW IN THE MORNING AND THEN TURNING TO ALL RAIN AS IT WARMS UP A
LITTLE IN THE AFTERNOON AND THEN A MIX OF RAIN AND SNOW AGAIN IN THE
EVENING WHEN THINGS COOL OFF AGAIN. AT WORST...A DUSTING OF SNOW IS
EXPECTED WITH THIS SYSTEM. SOME FLURRIES OR VERY LIGHT SNOW IS
POSSIBLE ON SATURDAY AS THE UPPER TROUGH MOVES THROUGH THE AREA.
THIS IS ALSO WHERE THE MODELS REALLY BEGIN TO DIVERGE WITH THE ECMWF
ABOUT 12 HOURS SLOWER WITH THE UPPER TROUGH PASSAGE. ALSO THE ECMWF
HAS A MUCH SHARPER AND DEEPER UPPER TROUGH THAN THE GFS. THE MODELS
THEN GET INTO BETTER AGREEMENT WITH A MORE ZONAL PATTERN DEVELOPING
ACROSS THE US. THE NEXT SYSTEM TO MOVE ACROSS EASTERN KENTUCKY WILL
BE ON TUESDAY. HERE THE ECMWF IS THE FASTER OF THE TWO SYSTEMS.
DECIDED TO GO WITH THE FASTER ECMWF FOR THE TUESDAY SYSTEM. THE
PATTERN THUS REMAINS ACTIVE...HOWEVER NO MAJOR SYSTEMS WITH BIG
IMPACT ARE EXPECTED. FOR THE TEMPERATES...GENERALLY NUDGED THE MODEL
BLEND TOWARD THE NEW AND GENERALLY WARMER ECMWF RAW DATA FOR THE
TEMPERATURE FORECAST.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z WEDNESDAY NIGHT)
ISSUED AT 151 AM EST WED FEB 13 2013
WITH STILL A DRY LOWER LAYER TO OVERCOME...MVFR AND IFR CEILINGS WILL
HOLD OFF TILL NEAR DAY BREAK FOR TAF SITES. PRECIP WILL FALL AFTER
12Z ACROSS THE AREA LOWERING VIS TO MVFR AND IFR CONDITIONS ALONG
WITH CEILINGS REMAINING OVER THE AREA THROUGH THE REST OF THE TAF
PERIOD. PRECIP SHOULD END ACROSS EASTERN KENTUCKY BY 03Z WITH
CEILINGS REMAINING THROUGH THE REST OF THE TAF PERIOD.
&&
.JKL WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...SHALLENBERGER
LONG TERM...SHALLENBERGER
AVIATION...SHALLENBERGER
AREA FORECAST DISCUSSION
NWS LOUISVILLE KY
329 AM EST WED FEB 13 2013
.Short Term (Now through Thursday)...
Issued at 325 AM EST Wed Feb 13 2013
...Light Slushy Snow Accumulations Possible Today...
As of 745Z, an upper trough was over MO with sfc low pressure over
the Gulf States. Precipitation associated with this system
stretched from western KY to eastern OK as of 745Z with rain
observed over most areas ESE of the upper trough and snow or a
rain/snow mix observed over portions of OK/MO/AR in the upper level
trough. The 6Z NAM12 and last few RAP runs seem to have the best
handle on the area of precipitation and general schematic of ptype.
Overall timing of the best precip and forcing seems to be a little
earlier than previously thought. Looks like the best dynamics and
precip should fall over our region between 12-18Z. Also, the latest
runs of the NAM and RAP have moved the best band of moderate to
heavy precip...probably a heavy wet snow as observed out in MO...to
the north. According to these models, the best snow band in which
we could see 1-2 inches of wet, slushy snow would be in a corridor
along the Ohio River to along the Western KY and Bluegrass
Parkways. Other areas over southern Indiana and south central KY
may see a brief mix of rain/snow...enough to create a dusting to a
half inch before quickly melting off. There is still some
uncertainty in where the band of moderate to heavy snow will set up
so stay tuned to morning forecast updates. Also, because of the
uncertainty, will continue with the SPS product instead of going
with an advisory although one may be needed later this morning.
So for today expect light rain to overspread the area before sunrise
with possibly some snow grains mixing in over southern Indiana and
northern KY at precip onset due to a deeper cold layer. After
sunrise we`ll start to see colder air filter in with the upper
trough causing precip to change over to a rain/snow mix and then
probably all snow for a time over southern Indiana and central KY.
The morning hours after sunrise through early afternoon will be the
best time for a period of moderate to heavy wet snow resulting in
slushy snow accumulations as high as 1-2 inches over north central
KY. This period of wintry precip may cause some travel issues.
We`ll continue to see a early afternoon before precip exits to our
east by late afternoon/early evening. Once snow comes to an end
over any location, quick melting can be expected as sfc temps are
expected to be above freezing today. In fact, most locations will
still top out in the upper 30s to lower 40s this afternoon despite
any morning/early afternoon snow.
For tonight and Thurs, expect dry conditions with partly cloudy
skies. Low temps will be in the upper 20s to lower 30s tonight. An
upper level trough and cold front will approach the region by Thurs
evening. Ahead of the trough, though, Thurs will be quite warm with
a strong southerly flow in place. High temps Thurs should be in the
low to mid 50s.
.Long Term (Thursday Night - Tuesday)...
Issued at 320 AM EST Wed Feb 13 2013
...A few shots for snow showers followed by a warm up and another
strong storm system early next week...
A lead shortwave will move across the Great Lakes on Thursday night,
with the associated surface system dragging a moisture starved cold
frontal boundary through the region. A secondary shortwave will
quickly move across the Ohio Valley on Friday as overall trough
envelopes the eastern CONUS. Friday looks to be the best setup for
some snow showers across the area as enough deep moisture combines
with steep low and mid level lapse rates, and an upslope surface
component. Soundings for this time period do show some convective
instability with saturation well into the -10 -20 C range across
northern portions of the CWA. Surface temperatures may squeak into
the mid and upper 30s on Friday, however thermal profile will be
easily cold enough for all snow showers below 40 degrees, some of
which could produce bursts of heavy snow and gusty winds.
At this point, best location for snow looks to be across southern
Indiana and north central Kentucky. As was mentioned in the previous
forecast, these snow showers have the potential to cause an impact
across the region with very light but quick accumulations. This setup
will have to be monitored.
We should see a lull in the activity on Friday night with subsidence
behind the quickly departing shortwave. Temperatures will be much
cooler with lows dropping into the mid 20s. By Saturday, confidence
is low as to exact placement of trough axis. Models are still having
trouble with the timing/placement of individual waves and the
overall progression of the east CONUS trough amplification. Have
continued the trend of a drier Saturday as a GFS/GEM/GFS ensemble
mean consensus agree on an eastern solution with subsidence aloft
already in place across the Ohio Valley on Saturday. The less
consistent ECMWF still holds the axis to the west. Will only mention
a slight chance of a snow shower east of I-65 to account for this.
May be able to go completely dry for Saturday with the next set of
model runs. Temperatures will be cooler than Friday with highs only
topping out in the low and mid 30s.
Saturday night/Sunday morning will be the coldest of the period as
lows drop to around 20. Radiational cooling conditions will not be
optimal as surface winds stay up a bit and some upper level clouds
look to stream overhead. Therefore, cannot drop low too near dew
points that will be in the lower teens. May be able to decouple a
few of the coolest spots into the upper teens but the upper level
cloud cover should mostly mitigate this.
Saturday night through most of Monday should be dry as surface high
pressure holds over the area and weak upper level ridging holds.
Sunday will begin the warming trend with highs warming into the mid
30s to low 40s. Highs on Monday will be much milder with a return of
southerly flow. The mercury should rebound to the low 50s in most
spots.
By Monday afternoon we will begin to focus on the next storm system
that looks to impact the area through Tuesday. This system will
develop as a lee surface low intensifies ahead of a digging trough
over the central Plains. At this point the low looks to move from
the southern Plains, northeastward either into the Ohio Valley or
just north to the lower Great Lakes through Tuesday morning. This
warmer solution would bring overrunning rain showers to the area
late Monday afternoon, with more widespread rain moving into the
area Monday night and early Tuesday. Temperatures will likely crash
quickly behind the system on Tuesday afternoon as sharp trough moves
through and may eventually have to mention rain changing to snow.
Will stick with all rain for now as it is too early to mention these
details, especially with the low track in question. Will also leave
any thunder mention out of the forecast with the bulk of the
precipitation as any moisture return/instability would be limited by
short duration of southerly flow. This system will have to be
watched however, as a more northerly solution or deeper sfc low
would change the instability picture. Also, chose to disregard the
more southern solution offered by the operational ECMWF. This seems
to be the outlier, with a general consensus between the GFS/GEM/GFS
ensemble mean/ECMWF ensemble mean of a northern solution.
&&
.Aviation (06Z TAF Issuance)...
Issued at 1215 AM EST Wed Feb 13 2013
An upper level trough will pass through the area today with a sfc
low pressure passing to our south. Precipitation associated with
this weather system has already begun to spread northward into south
central KY early this morning. Although it`s having problems
overcoming a significant dry layer, we are finally getting some
reports of rain in western KY and northern TN. With decent radar
returns over BWG as of 5Z, will go ahead and start this TAF with
VCSH. As moisture spreads northward through the early morning
hours, we`ll see rains move into BWG around 8Z...LEX around
10Z...and SDF around 11Z respectively. By late morning, good
forcing will enter the region causing steady moderate banded precip
over the region. It`s hard to say whether a moderate band will
affect the TAF sites, but at least feel confident enough to include
lower MVFR conditions from mid morning through early afternoon as
the heavier precip moves through the region. Some IFR cigs may be
possible in some of the heavier bands of precip but will not include
in the TAF at this time as confidence is low. Rain is expected to be
the predominant precip type for SDF/BWG, however, LEX could see a
RASN mix in a moderate band. A RASN mix isn`t out of the realm of
possibilities for SDF/BWG either, but seems most likely at LEX at
this time. Will need to adjust as the precip bands set up this
morning and move closer to our area. By mid to late afternoon,
precip should move east of the TAF sites with conditions returning
to high end MVFR and then VFR by this evening.
Winds will be light and variable early this morning and then become
predominantly NNE as the weather system approaches our area just
before sunrise. Winds will strengthen throughout the day likely
exceeding 7kt this afternoon. Winds will shift to the WNW behind
this system by this evening.
&&
.LMK WATCHES/WARNINGS/ADVISORIES...
IN...NONE.
KY...NONE.
$$
Short Term.......AMS
Long Term........BJS
Aviation.........AMS
AREA FORECAST DISCUSSION
NWS GAYLORD MI
1250 AM EST WED FEB 13 2013
.SYNOPSIS...
ISSUED AT 415 PM EST TUE FEB 12 2013
WEAK HIGH PRESSURE WILL BUILD INTO THE NORTHERN GREAT LAKES TONIGHT
AND WEDNESDAY. THIS PATTERN WILL GENERATE ABOVE NORMAL TEMPERATURES
AND OCCASIONAL FLURRIES...ACROSS THE NORTHERN MICHIGAN INTO THURSDAY.
HOWEVER...THE NEXT SYSTEM TO INFLUENCE THE GREAT LAKES ARRIVES
THURSDAY...BEFORE QUICKLY LIFTING NORTHEAST INTO QUEBEC FRIDAY. THIS
SYSTEM WILL GENERATE ANOTHER ROUND OF SNOW ACROSS NORTHERN
MICHIGAN THURSDAY...WHILE ALSO USHERING IN MUCH COLDER CONDITIONS
FRIDAY AND INTO THE WEEKEND. ACCUMULATING LAKE EFFECT SNOW CAN BE
EXPECTED OVER THE WESTERN GREAT LAKES THIS WEEKEND.
&&
.UPDATE...
ISSUED AT 1234 AM EST WED FEB 13 2013
LOW LEVEL STRATO CU LIKELY TO HANG ON THROUGH THE BALANCE OF THE
NIGHT WITH SHALLOW 925MB INSTABILITY HOLDS THROUGH 12Z...AND DUE
TO A NARROW CORRIDOR OF MID LEVEL MOISTURE SWEEPING OVERHEAD TO
GIVE IT A FIGHTING CHANCE. SOME BREAKS EXPECTED OUT THERE
HOWEVER...MAINLY GTV BAY AREA AND NE LOWER TOWARD DAYBREAK. QUIET
NIGHT. ALTHOUGH RELATIVELY INSIGNIFICANT...GOING AGAINST MODEL
SUGGESTIONS OF FLURRIES RE-FIRING IN WSW FLOW REGIMES AS SAID
MOISTURE SWEEPS IN OVERHEAD.
UPDATE ISSUED AT 930 PM EST TUE FEB 12 2013
FLURRIES HAVE TEMPORARILY ENDED ACROSS NW LWR MICHIGAN LATE THIS
EVENING THANKS TO BUILDING SUBSIDENCE AND SHALLOWING OF THE LOW
LEVEL MOIST LAYER. LATEST IR SATELLITE DOES SHOW A LINE OF COOLER
CLOUD TOPS OVER CENTRAL UPR MICHIGAN ASSOCIATED WITH A WEAK VORT
LOBE AND A NARROW BAND OF MID LEVEL MOISTURE. EXPECT THESE
FEATURES WILL LEND TO REDEVELOPMENT OF ADDITIONAL LAKE EFFECT
FLURRIES OVERNIGHT FOR FAR NRN AND NW LWR MICHIGAN AS WELL AS
PORTIONS OF ERN UPR MICHIGAN...STILL UNDER THE DIRECTION OF SW
LOW LEVEL FLOW. TEMPS CONTINUE TO FALL THRU THE 20S...ON THEIR WAY
TO THE UPPER TEENS AND LOWER 20S FOR OVERNIGHT LOWS.
UPDATE ISSUED AT 645 PM EST TUE FEB 12 2013
LAKE EFFECT FLURRIES CONTINUE TO STREAM INTO FAR NRN AND NW LWR
MICHIGAN THIS EVENING UNDER THE DIRECTION OF LOW LEVEL SW FLOW.
LOW CLOUDS REMAIN TRAPPED BELOW THE SUBSIDENCE INVERSION...
MAINTAINING OVC SKIES ACROSS OUR ENTIRE CWA EVEN AWAY FROM ANY
LAKE INFLUENCES. VERY LITTLE WILL CHANGE THRU THE NIGHT AS LOW
LEVEL MOISTURE/CLOUDS REMAINS STUCK BELOW THE INVERSION AND SW
FLOW CONTINUES TO PRODUCE FLURRIES FOR FAR NRN AND NW LWR
MICHIGAN. OVERNIGHT LOWS IN THE UPPER TEENS TO LOWER 20S LOOKS
REASONABLE GIVEN CURRENT SURFACE DWPTS IN THAT VCNTY.
&&
.SHORT TERM...(THIS EVENING THROUGH WEDNESDAY)
ISSUED AT 415 PM EST TUE FEB 12 2013
COLD AIR ADVECTION HAS ABOUT MAXED OUT BEHIND YESTERDAY`S DEPARTING
STORM...WITH LATEST HIGH RES RUC ANALYSIS PLACING CIRCA -11C H85
TEMPERATURES ACROSS THE NORTH WOODS. DESPITE EXCEEDINGLY LOW
INVERSIONS (H85 PER SAME RUC ANALYSIS)...MOISTURE DEPTH EXTENDING
TO THE LOW END OF THE FAVORED DGZ CONTINUES TO KICK OFF WIDESPREAD
FLURRIES IN FAVORED WEST FLOW LAKE AREAS. ABUNDANT LOW LEVEL
MOISTURE ALSO LEADING TO A MAINLY CLOUDY DAY...WITH ANY SUBSTANTIAL
CLEARING OF NOTE BACK ACROSS WISCONSIN. THIS CLEARING APPEARS TIED
TO DOWNWARD FORCING ON BACKSIDE OF RATHER COMPACT SHORTWAVE
PINWHEELING EAST INTO NORTHERN LAKE MICHIGAN. NO SIGNIFICANT
CONCERNS THROUGH THE SHORT TERM (WEDNESDAY)...ALTHOUGH LINGERING
FLURRIES AND CLOUD TRENDS WILL NEED ADDRESSING.
WISCONSIN SHORTWAVE WILL STEADILY AND RAPIDLY PUSH ACROSS THE AREA
THIS EVENING...AND LACK OF ANY APPRECIABLE MOISTURE SHOULD PRECLUDE
MUCH...IF ANY...LAKE OR SYNOPTIC RESPONSE. H85 TEMPERATURES SLOWLY
WARM IN DEVELOPING WEAK SOUTHWEST FLOW WAA REGIME...REACHING THE
NEGATIVE SINGLE DIGITS BY MORNING. NAM-WRF BUFFER SOUNDINGS SHOW LOW
LEVEL MOISTURE FALLING BELOW -10C ISOTHERM...WHICH COMBINED WITH
LOWERING DELTA T/S...WOULD SUPPORT A QUICK DEMISE TO ONGOING
FLURRIES. NOT WILLING TO BITE ON THIS JUST YET...AND PREFER TO KEEP
FLURRIES IN THE FORECAST...SIMPLY FOLLOWING THE WINDS FOR THERE
PLACEMENT (WHICH SUGGESTS THEY SHOULD CONFINE THEMSELVES IN FAVORED
SOUTHWEST FLOW AREAS THROUGH THE NIGHT). CLOUD COVER REMAINS A
FORMIDABLE CHALLENGE...ESPECIALLY GIVEN WHAT IS OCCURRING BEHIND
UPSTREAM WAVE. DO HAVE SOME TREPIDATION GOING TOO AGGRESSIVE WITH
CLOUDS OVERNIGHT...ESPECIALLY IN NON-FAVORED LAKE AREAS. SUBTLE WARM
ADVECTION AND POST-WAVE DOWNWARD RESPONSE JUST MAY WORK IN TANDEM TO
FORCE MUCH MORE CLEARING THAN THIS FORECAST WILL SUGGEST. WILL
TREND PARTLY CLOUDY ACROSS EASTERN UPPER AND NORTHEAST LOWER AS A
STARTING POINT...WITH KNOWLEDGE THAT COMPLETELY CLOUDY OR CLEAR IS
THE MORE LIKELY OUTCOME. TEMPERATURES...OF COURSE...HIGHLY DEPENDENT
ON HOW THIS WHOLE CLOUD THING UNFOLDS. MID AND UPPER TEENS MAY BE
SEVERAL DEGREES TOO "WARM". WE SHALL SEE.
SAME STORY HEADING INTO WEDNESDAY...WITH SOME LINGERING FLURRIES AND
MOSTLY TO PARTLY CLOUDY SKIES. LOW LEVEL MODIFICATION
CONTINUES...SUGGESTING HIGHS IN THE LOWER AND MIDDLE 30S.
.LONG TERM...(WEDNESDAY NIGHT THROUGH TUESDAY)
ISSUED AT 415 PM EST TUE FEB 12 2013
MAIN FORECAST CONCERNS WILL BE POTENTIAL FOR ACCUMULATING LAKE
ENHANCED SNOWS STARTING THURSDAY AND CONTINUING INTO THE
WEEKEND.
THE LATEST HEMISPHERIC ANALYSIS SHOWS A STABLE 3-WAVE PATTERN WITH
LARGE SCALE TROUGHING OVER CENTERED OVER JAMES BAY...EAST ASIA
/AROUND 120E/ AND CENTRAL EUROPE. A VERY STRONG ZONAL JET REMAINS
OVER EAST ASIA AND THE WESTERN PACIFIC...WITH A SLIT FLOW OVER THE
EASTERN PACIFIC EXTENDING INTO THE WEST COAST. THE SPLIT FLOW MERGES
TO FORM A FASTER JET THE SOUTHEASTERN U.S.
THURSDAY...AN AMPLIFYING PATTERN IS EXPECTED WITH STRONG PACIFIC JET
TO BEEF UP THE WEST COAST RIDGE...RESULTING IN INCREASED TROUGHING
OVER THE EASTERN TWO THIRDS OF THE CONUS BY THURSDAY. SHORT WAVE
ENERGY IS EXPECTED TO ROUND THE TOP OF THE RIDGE ON
WEDNESDAY...BEFORE DIVING INTO THE GREAT LAKES BY THURSDAY. AN
ASSOCIATED SURFACE RESPONSE/CLIPPER SYSTEM WILL MOVE THOUGH THE
GREAT LAKES...BRINGING NORTHERN MICHIGAN THE NEXT CHANCE OF SOME
LIGHT SNOW. THE AMOUNT OF MOISTURE THIS SYSTEM HAS TO WORK WITH IS
NOT TERRIBLE...WITH MODEL SOUNDINGS SHOWING P-WATS OF AROUND 0.3 TO
0.4 INCHES ACROSS THE CWA. THE DEGREE OF FORCING REMAINS IN SOME
QUESTION...WITH TWO DISTINCT AREAS OF ENHANCED PVA EXPECTED TO MOVE
THROUGH THE REGION EMBEDDED IN THE SHEARED PIECE OF ENERGY. THE
NAM/GFS WANT TO SPIN UP A STRONGER LOW WITH THIS FEATURE...WHILE THE
ECMWF/GEM KEEP THE SURFACE LOW MORE BENIGN. PREFER THE LATTER OF THE
SOLUTIONS...GIVEN THAT THESE TWO PIECES OF ENERGY DO NOT NECESSARILY
PHASE TOGETHER. OVERALL LOOKING LIKE A 1 TO 2..PERHAPS LOCALLY 3
INCH SNOW EVENT. RAPIDLY CHANGING FLOW AND WARMISH AIR ALOFT WITH
H85 TEMPS BETWEEN -5 TO -8C LOOK TO KEEP A MAJOR DAMPER OF ANY LAKE
ENHANCEMENT. SNOW MAY BE ALSO BE SLOW TO ACCUMULATE ON ROAD SURFACES
WITH SURFACE TEMPS AT OR SLIGHTLY ABOVE FREEZING...WITH THE MORE
AGGRESSIVE NAM/GFS SUGGESTING HIGHS IN THE MID TO UPPER 30S FOR
THURSDAY. THIS WOULD HAVE RAIN/SNOW MIX IMPLICATIONS FOR THE LOWER
ELEVATIONS OF THE CWA...BUT PREFER THE MORE COOLER...LESS AMPLIFIED
SOLUTIONS FOR NOW.
THURSDAY NIGHT AND FRIDAY...FORCING BEGINS TO PUSH EAST OF THE AREA
BY LATE THURSDAY AFTERNOON WITH STRONG COLD AIR ADVECTION ENSUING
ACROSS THE CWA THURSDAY NIGHT INTO FRIDAY. THIS WILL RAMP UP THE
LAKE EFFECT SNOW MACHINE DURING THIS TIMEFRAME. MODELS ARE NOT IN
THE BEST AGREEMENT WITH THE NAM/GFS MORE NORTHWESTERLY THAN THE NNW
FLOW DEPICTED BY THE ECMWF. MODEST INVERSION HEIGHTS AND DEEPEST
MOISTURE MOVING OUT SHOULD KEEP MAJOR LAKE SNOW ACCUMULATIONS IN
CHECK...HOWEVER SEVERAL INCHES OF ACCUMULATION LOOK LIKELY FOR THE
NW/NNW FAVORED SNOW BELTS THROUGH FRIDAY. H85 TEMPS FALL TO -15 TO
-18C DURING THE DAY FRIDAY...WITH MODEL CONSENSUS SHOWING HIGHS
STRUGGLING TO MAKE IT OUT OF THE TEENS.
FRIDAY NIGHT THROUGH TUESDAY...CHILLY CONDITIONS ENSUE AS DEEP
TROUGH SETTLES INTO THE GREAT LAKES WITH MODEL CONSENSUS SHOWING H85
TEMPS IN THE -18 TO -22 RANGE ACROSS THE GREAT LAKES INTO THE DAY ON
SATURDAY. CERTAINLY PLENTY OF INSTABILITY TO KEEP THE LAKE EFFECT
SNOW MACHINE GOING...WITH POCKETS OF DEEPER H85-H7 MOISTURE
ASSOCIATED WITH EMBEDDED SHORTWAVES ROUNDING THE LONGER WAVE TROUGH
AND CONTINUED NORTHWEST TO NORTH NORTHWEST FLOW. AT THE
LEAST...SEVERAL INCHES OF ACCUMULATION LOOK LIKELY IN THE NW TO NNW
FAVORED SNOW BELTS WITH THIS PATTERN. LOOKING AT SOME OF COOP
SNOWFALL GUIDANCE FROM THE CIPS ANALOGS FOR THE 72 HOUR PERIOD
CENTERED ON 00Z/17 SHOWS HEAVY ACCUMULATIONS FOR 3 OF THE TO 5
ANALOGS. STILL PLENTY OF DETAILS TO WORK OUT BETWEEN NOW AND THIS
WEEKEND...WITH ICE COVER OVER NORTHERN LAKE MICHIGAN AND MODEST
INVERSION HEIGHTS SERVING AS MITIGATING FACTORS FOR HEAVY
ACCUMULATIONS. STILL COULD SEE THE POSSIBILITY OF SOME HEADLINES FOR
THE FRI/SAT TIMEFRAME...AND WILL MAINTAIN THE THREAT FOR
ACCUMULATING LAKE SNOWS IN THE HWO.
SUNDAY THROUGH MONDAY...PROGRESSIVE PATTERN CONTINUES WITH DEEP
TROUGH KICKING OFF TO THE NORTHEAST AND HEIGHTS MODIFYING
SUBSTANTIALLY AS UPSTREAM RIDGING BUILDS INTO THE GREAT LAKES.
1000-850 MEAN FLOW IS PROGGED TO BACK TO THE SOUTHWEST WITH H85
TEMPS MODIFYING ENOUGH TO END THE LES THREAT...ALTHOUGH THERE MAY BE
SOME LINGER -SHSN FOR SW FAVORED FLOW AREAS INITIALLY SUNDAY
MORNING. ANOTHER CLIPPER SYSTEM LOOKS TO TRAVERSE THE AREA SUNDAY
NIGHT INTO MONDAY...HOWEVER THE BETTER MOISTURE AND FORCING LOOK TO
REMAIN OVER THE NORTHERN PORTION OF THE CWA ATTM.
MONDAY NIGHT INTO TUESDAY...NEXT TROUGH BUILDS INTO THE GREAT LAKES
WITH GFS/ECMWF DEPICTING A STORM SYSTEM DEVELOPING IN THE SOUTHERN
PLAINS AND MOVING UP THROUGH THE OHIO VALLEY INTO THE GREAT LAKES.
NOT A LOT OF CONFIDENCE OF COURSE THIS FAR OUT...ESPECIALLY WHEN
LOOKING AT SOME OF THE ENSEMBLE GUIDANCE ON THE UPPER AIR
PATTERN...BUT SOME SIGNALS ARE THERE OF SAID SYSTEM WHEN LOOKING AT
THE REANALYSIS BASED ON THE TOP GFS/CAN ENS TOP ANALOGS. SOMETHING
THAT WILL CERTAINLY NEED TO BE MONITORED.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z WEDNESDAY NIGHT)
ISSUED AT 1234 AM EST WED FEB 13 2013
MVFR CIGS LIKELY TO HANG ON THROUGH MUCH OF THE NIGHT...AND
EVEN INTO A FEW HOURS AFTER DAYBREAK. THIS AIDED BY SHALLOW
OVERLAKE INSTABILITY AND WEAK DISTURBANCE/CORRIDOR OF MID LEVEL
MOISTURE ALOFT SWEEPING THROUGH. DO BELIEVE THE MVFR CIGS WILL MIX
OUT...ALTHOUGH WINDS/MIXING NOT SO IMPRESSIVE HEADING INTO
TOMORROW. WILL GO VFR WITH BROKEN MID/HIGH CLOUD AROUND FOR MUCH
OF THE DAY AND INTO THE EVENING. AN ALBERTA CLIPPER ARRIVES LATE
TOMORROW NIGHT...BRINGING POSSIBLE SNOWS AND MVFR CIGS BACK INTO
NW LOWER AFTER THE TAF PERIOD.
WINDS WILL BE RELATIVELY LIGHT OUT OF THE SW.
&&
.MARINE...
ISSUED AT 415 PM EST TUE FEB 12 2013
MARINE...VEERING WINDS TO SOUTHWEST REMAIN SOMEWHAT GUSTY HEADING
INTO THIS EVENING. MAY EVEN SEE SOME SCA PRODUCING GUSTS ALONG THE
NORTHWEST LOWER LAKE MICHIGAN COAST...ALTHOUGH DURATION DOES NOT
SUPPORT A SPECIFIC SCA HEADLINE. SOUTHWEST AND SUB-ADVISORY WINDS TO
CONTINUE THROUGH THURSDAY MORNING.
&&
.APX WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LH...NONE.
LM...NONE.
LS...NONE.
&&
$$
UPDATE...SD
SYNOPSIS...SR
SHORT TERM...MB
LONG TERM...NS
AVIATION...SD
MARINE...MB
AREA FORECAST DISCUSSION
NWS BLACKSBURG VA
443 AM EST WED FEB 13 2013
.SYNOPSIS...
LOW PRESSURE OVER ALABAMA WILL TRACK NORTHEAST INTO VIRGINIA THIS
AFTERNOON...THEN OFF THE EAST COAST TONIGHT. THIS SYSTEM EXITS
THURSDAY MORNING. ANOTHER LOW CROSSING THROUGH THE GREAT LAKES
WILL PUSH A COLD FRONT THROUGH THE REGION ON FRIDAY AND SATURDAY.
HIGH PRESSURE WILL BE OVER THE AREA ON SUNDAY AND MONDAY.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 430 AM EST WEDNESDAY...
PERSISTENT BAND OF RAIN OVER THE SOUTHERN COUNTY WARNING AREA WAS
ORIENTED ALONG AND WELL NORTH OF THE WARM FRONT. DON`T EXPECT MUCH
EXPANSION OF THE AREAL COVERAGE OF PRECIPITATION UNTIL THE UPPER
LOW GETS CLOSER. LOCAL WRF FROM 00Z ALONG WITH RAP MODELS AND
BUFKIT HAVE MORE WIDESPREAD PRECIPITATION ARRIVING IN THE WESTERN
COUNTY WARNING AREA AROUND 7AM AND REACHING EASTERN COUNTIES
BEFORE NOON.
DURING THE DAY THE SURFACE LOW MOVES FROM ALABAMA THIS MORNING
INTO SOUTHWEST VIRGINIA THIS AFTERNOON. FORECAST AREA STAYS NORTH
OF THE WARM FRONT. EXPECT ENOUGH EAST TO SOUTHEAST SURFACE AND LOW
LEVEL WINDS TO ENHANCE THE PRECIPITATION AMOUNTS ON EASTERN SLOPES
THROUGH 00Z/7PM TONIGHT. BEST SYNOPTIC LIFT ARRIVES WITH THE UPPER
LOW.
MODELS MORE IN LINE WITH TEMPERATURE PROFILE TODAY AND TONIGHT.
MAINLY USED A NAM/RAP BLEND FOR TEMPERATURES AND PRECIPITATION
TYPE...WHICH WAS SLIGHTLY COOLER THAN THE GFS. EVEN THE COOLER
GUIDANCE LIMITED ANY WINTER PRECIPITATION TO THE VERY HIGHEST
ELEVATIONS FROM NORTHWEST NORTH CAROLINA INTO TAZEWELL
COUNTY...AND FROM MERCER COUNTY INTO BATH COUNTY. THE COMBINATION
OF STRATIFORM SNOWFALL FROM THE UPPER LOW TODAY AND UPSLOPE SNOW
SHOWERS THIS EVENING STILL SUPPORTS SNOW ACCUMULATIONS THAT REACH
ADVISORY CRITERIA ONLY IN GREENBRIER COUNTY. SO NO CHANGES TO THE
ADVISORY NEEDED AT THIS TIME.
STAYED COOLER THAN GUIDANCE FOR BOTH HOURLY TEMPERATURES AND
MAXIMUM TEMPERATURES FOR TODAY. MORE TYPICAL DIURNAL/COLD AIR
ADVECTION TREND EXPECTED FOR TONIGHT.
&&
.SHORT TERM /THURSDAY THROUGH SATURDAY NIGHT/...
AS OF 400 AM EST WEDNESDAY...
BY SUNRISE THURSDAY...EXPECT TO SEE SNOW SHOWER ACTIVITY ACROSS THE
MOUNTAINS COMING TO AN END AND WIND SPEEDS DIMINISHING AS HIGH
PRESSURE...BUILDING IN FROM THE GULF COAST REGION...BECOMES THE
DOMINANT FEATURE OF THE MOMENT IN OUR PROGRESSIVE WEATHER PATTERN.
RELATIVELY ZONAL FLOW ALOFT WILL HELP MAINTAIN MILD TEMPERATURES...
AND EXPECT AFTERNOON HIGHS TO RANGE FROM THE MID TO UPPER 40S ACROSS
THE MOUNTAINS...TO THE MID 50S ACROSS THE PIEDMONTS.
COME EARLY FRIDAY AFTERNOON HOWEVER...WE CAN EXPECT ANOTHER STRONG
COLD FRONT TO MOVE ACROSS THE AREA...USHERING IN A SHOT OF ARCTIC
AIR. WITH THE ARRIVAL OF THE COLD FRONT...WILL ALSO SEE ANOTHER
ROUND OF SNOW SHOWERS DEVELOP ACROSS THE MOUNTAINS...WITH THE
HIGHEST SNOWFALL AMOUNTS OCCURRING IN THE USUAL NORTHWEST WIND
UPSLOPE AREAS. WINDS WILL ALSO BE ON THE GUSTY SIDE THROUGH THE DAY
THANKS TO A 5MB TO 6MB PRESSURE GRADIENT ACROSS THE AREA BETWEEN LOW
PRESSURE OVER EASTERN CANADA...AND HIGH PRESSURE BUILDING ACROSS THE
PLAINS. GUSTY WINDS WILL CONTINUE THROUGH FRIDAY NIGHT AND EARLY
SATURDAY MORNING...CAUSING WIND CHILL TEMPERATURES TO RANGE FROM THE
POSITIVE SINGLE DIGITS IN SOUTHEAST WEST VIRGINIA...TO THE 20S
ACROSS THE PIEDMONTS.
MOUNTAIN SNOW SHOWER ACTIVITY WILL CONTINUE ON SATURDAY...AND
BELIEVE THAT PORTIONS OF OUR FORECAST AREA FROM THE NORTH CAROLINA
MOUNTAINS THROUGH THE ALLEGHANY HIGHLANDS WILL HAVE A HARD TIME
RISING ABOVE FREEZING FOR DAYTIME HIGHS THANKS TO A DEEP UPPER LEVEL
TROUGH BUILDING SOUTHWARD FROM EASTERN CANADA THROUGH THE GULF
COAST. THE TROUGH REMAINS PROGRESSIVE HOWEVER...AND WILL CONTINUE AN
EASTWARD JOG THROUGH SATURDAY NIGHT...EVENTUALLY PUSHING OFF THE
ATLANTIC COAST BY SUNDAY MORNING.
&&
.LONG TERM /SUNDAY THROUGH TUESDAY/...
AS OF 400AM EST WEDNESDAY...
A PATTERN CHANGE TO RIDGING IN THE EAST STILL LOOKS PROMISING AS
WE HEAD INTO EARLY NEXT WEEK. TEMPERATURES WILL START TO TREND
MILDER...AND PRECIPITATION WILL START TO ENTER THE REGION MONDAY
NIGHT IN THE WEST AS SOUTHERLY WINDS START TO ADVECT MOISTURE FROM
THE GULF IN ADVANCE OF OUR NEXT APPROACHING TROUGH. A COLD FRONT
IS EXPECTED TO BE ON OUR WESTERN DOORSTEP BY LATE TUESDAY
AFTERNOON. EXPECT INCREASING CHANCE OF SHOWERS THROUGH THE
DAY...THE THE BEST COVERAGE IN THE WEST. THE CHANCES OF A GUSTY
DAY LOOK PROMISING AS FORECAST 850 MB WINDS AHEAD OF THE FRONT ARE
IN THE 60 TO 70 KT RANGE. WHILE GUIDANCE DOES NOT INDICATE WE WILL
HAVE MUCH IN THE WAY OF INSTABILITY...LOW LEVEL SHEAR WILL LIKELY
BE HIGH.
&&
.AVIATION /10Z WEDNESDAY THROUGH SUNDAY/...
AS OF 100 AM EST WEDNESDAY...
RADAR IMAGERY INDICATES THAT THE FIRST ROUND OF PRECIPITATION HAS
PASSED THE AREA THIS MORNING...REMAINING CONFINED MAINLY TO NORTH
CAROLINA AND EXTREME SOUTHERN VIRGINIA...AND PASSING ACROSS DAN.
CURRENTLY LOOKING AT MAINLY VFR CEILINGS...BUT EXPECT THAT TO
CHANGE BEFORE SUNRISE AS AN APPROACHING UPPER TROUGH...AND
ASSOCIATED SURFACE LOW...MOVES INTO THE AREA. LOW END MVFR AND
IFR CEILINGS WILL DEVELOP DURING THE 09Z TO 12Z TIME FRAME AS
SOUTHEASTERLY WIND FLOW ACROSS THE AREA INCREASES. PRECIPITATION...
MAINLY IN THE FORM OF RAIN MIXED OCCASIONALLY WITH SLEET OR
SNOW...WILL BECOME WIDESPREAD THROUGH THE DAY AS THE LOW PASSES
THE AREA DURING THE AFTERNOON.
AS THE LOW MOVES TO THE COAST DURING THE EVENING...WINDS WILL
SHIFT NORTHWESTERLY...BRINGING COLDER AIR INTO THE AREA AND
CAUSING RAIN TO CHANGE TO SNOW SHOWERS. WILL LIKELY BE LOOKING A
BRIEF PERIOD OF SNOW FOR ROA...DAN AND LYH BEFORE MOISTURE MOVES
OUT OF THE AREA...HOWEVER SNOW SHOWERS WILL LINGER THROUGH THE
NIGHT FURTHER TO THE WEST. EXPECT SNOW SHOWERS TO END AT ALL
AIRPORTS BY SUNRISE THURSDAY. WILL ALSO EXPERIENCE GUSTY WINDS
THROUGH THE NIGHT THANKS TO A TIGHT PRESSURE GRADIENT BETWEEN THE
DEPARTING LOW AND APPROACHING HIGH PRESSURE.
AN ARCTIC COLD FRONT IS EXPECTED TO CROSS THE REGION FRIDAY NIGHT
WITH GUSTY WINDS...AND PERHAPS A PERIOD OF MOUNTAIN MVFR CIGS
INCLUDING SNOW OR SNOW SHOWERS INTO SATURDAY.
&&
.RNK WATCHES/WARNINGS/ADVISORIES...
VA...NONE.
NC...NONE.
WV...WINTER WEATHER ADVISORY UNTIL MIDNIGHT EST TONIGHT FOR WVZ045.
&&
$$
SYNOPSIS...AMS
NEAR TERM...AMS
SHORT TERM...NF
LONG TERM...DS
AVIATION...DS/NF/WP
AREA FORECAST DISCUSSION
NWS EUREKA CA
358 AM PST WED FEB 13 2013
.SYNOPSIS...
A STRONG AND PERSISTENT RIDGE OF HIGH PRESSURE WILL KEEP NORTHWEST
CALIFORNIA DRY THROUGH AT LEAST SATURDAY MORNING. WHILE MORNING
CLOUDS ALONG THE NORTH COAST WILL GIVE WAY TO SUNSHINE THERE WILL
STILL BE A COOL BREEZE THIS AFTERNOON. INTERIOR AREAS WILL STAY
SUNNY OUTSIDE OF AREAS OF VALLEY FOG. OFFSHORE FLOW WILL BRING
WARMER CONDITIONS TO THE COAST LATER THURSDAY AND FRIDAY.
&&
.SHORT TERM...
STRATUS IS MUCH MORE WELL-ESTABLISHED ALONG THE COAST BETWEEN CAPE
MENDOCINO AND TRINIDAD EARLY THIS MORNING. WITH UPPER RIDGING
BUILDING OVER THE EASTERN PACIFIC SFC HIGH PRESSURE HAS
STRENGTHENED...RESULTING IN AN INCREASED ONSHORE GRADIENT ALONG THE
IMMEDIATE COAST. RUC ANALYSIS SHOWS THE THERMAL TROUGH TO BE A BIT
WEAKER AND ORIENTED FURTHER INLAND...ALLOWING THE NORTHERLY FLOW TO
RETURN TO THE MENDOCINO COAST AND KEEP ANY STRATUS WELL TO THE SOUTH
OR FURTHER OFFSHORE. MEANWHILE ENOUGH OFFSHORE FLOW STILL EXISTS
CLOSER TO THE SFC RIDGE AXIS IN SOUTHERN OREGON TO KEEP CRESCENT
CITY MOSTLY CLEAR. EXPECT THE STRATUS TO ERODE THIS AFTERNOON AS
BOUNDARY LAYER NORTHERLY WINDS INCREASE. EXPECT SIMILAR CONDITIONS
TONIGHT WITH EVEN MORE BOUNDARY LAYER MOISTURE AND A STRONGER
INVERSION AS THE RIDGE PUSHES CLOSER TO THE WEST COAST. UPPER LEVEL
RIDGING WILL CONTINUE TO PUSH EASTWARD TOWARD THE WEST COAST ON
THURSDAY AND THE RIDGE AXIS WILL PASS BY FRIDAY MORNING. THIS WILL
ALLOW HIGH PRESSURE BOTH AT THE SFC AND ALOFT TO BUILD OVER THE
PACIFIC NORTHWEST AND EVENTUALLY THE GREAT BASIN...WHILE THE THERMAL
TROUGH PUSHES WESTWARD OFF THE COAST. INCREASING OFFSHORE FLOW WILL
RESULT LATER THURSDAY INTO FRIDAY WITH CLEAR SKIES AND LIGHT WINDS
ACCOMPANIED BY ABOVE NORMAL TEMPERATURES. EVEN THE IMMEDIATE COAST
WILL REACH 60 DEGREES WITH 70S ACROSS THE INTERIOR VALLEYS. AAD
.LONG TERM...
BY SATURDAY AFTERNOON ONSHORE FLOW WILL RETURN WITH BOUNDARY LAYER
MOISTURE INCREASING AGAIN AT THE COAST. TEMPERATURES WILL BEGIN TO
COOL WITH INCREASING CLOUD COVER...ALONG WITH A SLIGHT CHANCE OF
SHOWERS. MODELS DO NOT SHOW ANY MEASURABLE RAINFALL SOUTH OF THE
OREGON BORDER AS MOISTURE WILL BE VERY LIMITED. AS SUCH DO NOT
EXPECT MORE THAN A SHOWER OR TWO IN THE LIMITED FORCING ALONG THE
WEAKENING COLD FRONT. MAY NEED TO ADD FOG AND DRIZZLE OVERNIGHT INTO
SUNDAY MORNING WITH THE ONSHORE PUSH OF BOUNDARY LAYER MOISTURE. BY
SUNDAY THE AIRMASS WILL DRY OUT WITH NORTHERLY FLOW RETURNING AS
HIGH PRESSURE BUILDS BACK OVER THE EASTERN PACIFIC. A MORE
SIGNIFICANT SYSTEM WILL APPROACH BY MONDAY NIGHT IN THE FORM OF AN
UPPER LEVEL LOW DROPPING SOUTHEASTWARD FROM THE GULF OF ALASKA.
ALTHOUGH MODELS ARE SIMILAR IN THE GENERAL PATTERN NEXT WEEK THERE
ARE SOME SIGNIFICANT DIFFERENCES WITH RESPECT TO THE DETAILS. HAVE
OPTED TO RAISE POPS TO AROUND DOUBLE CLIMO AS THERE IS HIGH
CONFIDENCE IN A PERIOD OF SHOWERS AND MOUNTAIN SNOW CENTERED AROUND
TUESDAY. THAT SAID PRECIPITATION AMOUNTS AND THE DEGREE OF COLD AIR
WITH THE SYSTEM ARE VERY MUCH UP IN THE AIR. AAD
&&
.AVIATION...11-4U SAT IMAGERY SHOWS OFFSHORE FLOW RESULTING IN
CLEARING STRATUS N OF TRINIDAD. PATCHY FG N OF TRINIDAD WILL RESULT
IN MVFR VSBYS/IFR CIGS THROUGH 17Z. GREATER ONSHORE COMPONENT S OF
TRINIDAD WILL RESULT IN IFR TO MVFR CIGS AROUND HUMBOLDT BAY AND THE
EEL RIVER VALLEY INTO NRN MENDO COUNTY THROUGH 20Z. VFR CONDITIONS
WILL PERSIST THROUGH THE AFTERNOON THEN DETERIORATE THIS EVENING.
STRATUS/FG WILL IMPACT AREAS AROUND HUMBOLDT BAY AS EARLY AS 14/00Z
WITH IFR CONDITIONS EXPANDING ALONG THE COAST AND INLAND
OVERNIGHT.
&&
.MARINE...BUOY OBS SHOW NLY WINDS REMAINING AROUND 20 KT N OF CAPE
MENDO WITH SEAS AROUND 10 FT. WINDS WILL INCREASE AGAIN THIS
AFTERNOON THEN DECREASE LATE THU. LONG PERIOD WAVE GROUP WILL
CONTINUE TO DECAY THIS MORNING WITH FORERUNNERS FROM ANOTHER WAVE
GROUP BUILDING INTO THE WATERS THIS AFTERNOON/EVENING. A 3RD WAVE
TRAIN WILL ARRIVE LATE FRI/EARLY SAT AND PERSIST THROUGH THE
WEEKEND.
&&
.EKA WATCHES/WARNINGS/ADVISORIES...
CA...NONE.
NORTHWEST CALIFORNIA COASTAL WATERS...
SMALL CRAFT ADVISORY UNTIL 9 PM PST THURSDAY PZZ450.
SMALL CRAFT ADVISORY UNTIL 9 AM PST FRIDAY PZZ470.
SMALL CRAFT ADVISORY FROM 9 AM THIS MORNING TO 3 PM PST THURSDAY
PZZ455.
SMALL CRAFT ADVISORY UNTIL 3 AM PST FRIDAY PZZ475.
&&
$$
VISIT US AT HTTP://WWW.WEATHER.GOV/EUREKA
FOLLOW US ON FACEBOOK AND TWITTER AT:
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HTTP://WWW.TWITTER.COM/NWSEUREKA
AREA FORECAST DISCUSSION
NWS COLUMBIA SC
1041 AM EST WED FEB 13 2013
.SYNOPSIS...
LOW PRESSURE WILL BE LIFTING NORTHEAST OF THE FORECAST AREA THIS
AFTERNOON AND TONIGHT. WEAK HIGH PRESSURE WILL DOMINATE THURSDAY AND
FRIDAY.
&&
.NEAR TERM /THROUGH TONIGHT/...
LOW PRESSURE CENTERED NEAR THE FORECAST AREA WAS SUPPORTING AREAS
OF LIGHT RAIN AND DRIZZLE. LATER TODAY...THE LOW WILL BE FARTHER
NORTH OF THE AREA AND ISENTROPIC DOWNGLIDE WILL BECOME DOMINATE.
THE RAIN CHANCE SHOULD DECREASE. THE NAM AND GFS INDICATED H85
WINDS OF 40 TO 50 KNOTS AND THE KCAE 88D HAS VERIFIED THESE WINDS.
THE MODELS SHOWED THIS WIND CONTINUING FOR MUCH OF THE DAY...THEN
DIMINISHING LATE TODAY AND TONIGHT. LINGERING CLOUDINESS SHOULD
LIMIT MIXING...BUT WITH THE DRYING IN THE AFTERNOON IT SHOULD
BECOME BREEZY. THE NAM MOMENTUM TRANSFER INDICATED A POTENTIAL FOR
GUSTS NEAR 30 KNOTS. THE HRRR INDICATED WIND GUSTS OF 25 TO 30
KNOTS DEVELOPING IN THE SOUTH PART AROUND 100 PM...WITH GUSTS OF
30 TO 35 KNOTS OVER MUCH OF THE REMAINING AREA BEGINNING AROUND
300 PM. WE HAVE POSTED A LAKE WIND ADVISORY. MODEL TIME SECTIONS
SHOW FURTHER DRYING OVERNIGHT AND EXPECT SKIES WILL BECOME CLEAR.
WE USED THE GUIDANCE CONSENSUS FOR THE TEMPERATURE FORECAST.
&&
.SHORT TERM /THURSDAY THROUGH FRIDAY NIGHT/...
THE NAM AND GFS SHOW WEAK RIDGING DOMINATING THURSDAY INTO FRIDAY. A
REINFORCING DRY COLD FRONT APPEARS TO CROSS THE AREA FRIDAY
AFTERNOON AND EVENING. GUIDANCE AND LOCAL NUMBERS ARE VERY CLOSE
THROUGH THE PERIOD.
&&
.LONG TERM /SATURDAY THROUGH TUESDAY/...
ALL OF THE MODELS SHOW A DEEP...PROGRESSIVE...TROUGH ACROSS THE
EASTERN HALF OF THE COUNTRY SATURDAY. THE ECMWF AND GFS DIFFER ON
THE SPEED AND STRENGTH OF ADDITIONAL UPPER-LEVEL ENERGY MOVING
THROUGH THE TROUGH AND EVENTUALLY HELPING TO LIFT THE TROUGH TO
THE EAST AND NORTHEAST BY SUNDAY OR MONDAY. THE GFS DEVELOPS LOW
PRESSURE OFF THE MID ATLANTIC COAST SATURDAY AND IS FASTER. THE
SLOWER ECMWF...DEVELOPS LOW PRESSURE OFF THE CAROLINA COAST
SATURDAY NIGHT AND SUNDAY MORNING. AT THIS TIME...WILL KEEP THE
FORECAST DRY FOR THE WEEKEND. THIS WILL BE FOLLOWED BY ANOTHER
QUICK MOVING SYSTEM APPROACHING THE REGION TUESDAY. THE MODELS
AGREE SHOWING A MOISTURE INCREASE TUESDAY ASSOCIATED WITH A COLD
FRONT. THE GFS AND ECMWF MOS SUPPORT BELOW NORMAL TEMPERATURES
SATURDAY THROUGH MONDAY...AND NEAR NORMAL DURING THE REST OF THE
MEDIUM-RANGE PERIOD.
&&
.AVIATION /16Z WEDNESDAY THROUGH SUNDAY/...
A WARM FRONT WILL SLOWLY LIFT NORTHWARD INTO THE AREA FROM CENTRAL
GEORGIA THIS MORNING. EXPECT IFR OR LIFR CEILINGS THROUGH THE REST
OF THE MORNING WITH PATCHY LIGHT SHOWERS OR DRIZZLE AT TIMES.
AS THE WARM FRONT LIFTS NORTH OF THE AREA CONDITIONS SHOULD
IMPROVE AND AS LOW CLOUDS LIFT AFTER 17Z-20Z. DEEP MIXING WITHIN AN
INCREASING PRESSURE GRADIENT/COLD FRONTAL PASSAGE FROM THE
WEST...WILL RESULT IN STRONG SOUTHWEST TO WESTERLY WINDS WITH GUSTS
TO 25 KNOTS.
EXTENDED AVIATION OUTLOOK...NO SIGNIFICANT IMPACTS TO AVIATION
EXPECTED.
&&
.CAE WATCHES/WARNINGS/ADVISORIES...
SC...LAKE WIND ADVISORY UNTIL 8 PM EST THIS EVENING FOR SCZ015-016-
018-020>022-025>031-035>038-041.
GA...LAKE WIND ADVISORY UNTIL 8 PM EST THIS EVENING FOR GAZ040-
063>065-077.
&&
$$
AREA FORECAST DISCUSSION
NWS PEACHTREE CITY GA
626 AM EST WED FEB 13 2013
.PREV DISCUSSION... /ISSUED 423 AM EST WED FEB 13 2013/
SHORT TERM /TODAY THROUGH THURSDAY/...
LOW PRESSURE IS CURRENTLY ACROSS NORTHERN AL AND THE ASSOCIATED COLD
FRONT STRETCHES INTO THE GULF OF MEXICO. A WARM FRONT IS ALSO
SITUATED ALONG THE GA/FL BORDER. REGIONAL RADAR SHOWS THE HEAVIEST
PRECIP IN THE VICINITY OF A WEAK LOW PRESSURE MOVING EAST ALONG THE
WARM FRONT.
THE COLD FRONT WILL MOVE THROUGH THE NW HALF OF THE CWA DURING THE
EARLY MORNING AND THE REMAINDER OF THE CWA BY THE EARLY AFTERNOON.
MODELS HAVE BEEN AGGRESSIVE WITH MOVING THE WARM FRONT
NORTHWARD...BUT THE COOLER HIGH PRESSURE WEDGE HAS HELD FIRM AND
ALLOWED LITTLE NORTHWARD PROGRESSION. WITH BOUNDARY LAYER WINDS 15
TO 20 KT OUT OF THE SOUTH...DO THINK THAT THERE WILL BE A LITTLE
NORTHWARD PROGRESSION OF THE WARM SECTOR THIS MORNING...THUS THE
BEST INSTABILITY WILL REMAIN ACROSS THE SOUTHERN ZONES. WITH STEEP
MID LEVEL LAPSE RATES AND BUFKIT SOUNDINGS SHOWING AN INVERTED V
STRUCTURE...LARGE HAIL AND DAMAGING WIND GUSTS WOULD BE THE PRIMARY
MODE OF SEVERE WEATHER. HOWEVER...DO THINK IF SEVERE THUNDERSTORMS
DEVELOP THEY WILL BE ISOLATED IN NATURE.
PRECIP CHANCES WILL DIMINISH FROM WEST TO EAST BEHIND THE COLD FRONT
LATER THIS AFTERNOON. OVERNIGHT AND THURSDAY ARE EXPECTED TO REMAIN
DRY AS HIGH PRESSURE BUILDS OVERHEAD.
TOOK BLEND FOR MAX/MIN TEMPS.
NLISTEMAA
LONG TERM /THURSDAY NIGHT THROUGH TUESDAY/...
GFS AND ECMWF ARE IN CLOSE AGREEMENT IN THE LONG TERM. THE EASTERN
TROUGH DEEPENS AS A STRONG SHORT WAVES MOVES OUT OF CANADA AND INTO THE
CENTRAL AND EASTERN U.S. THIS WILL DRIVE AN ARCTIC FRONT INTO THE
CWA FRIDAY AND FRIDAY NIGHT. WITH EACH MODEL RUN THE MOISTURE IS
SHOWING UP LESS AND LESS AND APPEARS THAT LITTLE IF ANY PRECIP WILL
FALL FROM THIS SHORT WAVE. THE ONLY AREAS THAT COULD SEE SOME LIGHT
RAIN WILL BE EXTREME NORTH GA DURING THE DAY FRIDAY. CONTINUED
UPSLOPE FLOW IN THE NORTHEAST MOUNTAINS COULD YIELD A FEW SNOW
SHOWERS DURING THE DAY SATURDAY. STRONG COLD ADVECTION SATURDAY
COUPLED WITH 30 TO 40 KT H8 WINDS WILL YIELD WINDY CONDITIONS ON
SATURDAY ACROSS THE CWA. STILL LOOKS LIKE GFS GUIDANCE IS TOO WARM
ON THIS WEEKEND TEMPS AND HAVE DROPPED THEM CONSIDERABLY.
THIS ARCTIC SURGE WILL BE SHORT LIVED AS THE FLOW BECOMES ZONAL BY
MONDAY MORNING. THE SURFACE HIGH WILL BE TO OUR EAST WITH ANOTHER
SYSTEM DEVELOPING OVER THE MIDDLE OF THE COUNTY. TEMPS WILL MODERATE
BEGINNING MONDAY AFTER A COLD START. BY MONDAY EVENING/TUESDAY
MOISTURE WILL RETURN TO THE CWA. MOST OF THE ENERGY APPEARS TO BE IN
THE OHIO VALLEY BUT ANOTHER COLD FRONT WILL MOVE ACROSS THE CWA
TUESDAY BRINGING A CHANCE OF SHOWERS AND THUNDERSTORMS.
17
&&
.AVIATION...
12Z UPDATE...
LIFR CIGS AT THE TERMINALS THIS MORNING SHOULD CONTINUE UNTIL A W/SW
WIND SHIFT OCCURS BETWEEN 15-17Z. GUSTS 20-25 KT WILL BE POSSIBLE. A
COLD FRONT WILL ALSO MOVE THROUGH DURING THE LATE MORNING AND EARLY
AFTERNOON. HRRR PRODUCES A BROKEN LINE OF SHOWERS ALONG THE
FRONT...AND HAVE TRIED TO TIME THAT. WILL NOT REDUCE VSBSY AS PRECIP
WILL REMAIN SCT IN NATURE. VFR CONDITIONS AFTER 00-002Z.
//ATL CONFIDENCE...12Z UPDATE...
MEDIUM CONFIDENCE ON CIGS AND VSBY. HIGH CONFIDENCE ALL OTHER ELEMENTS.
NLISTEMAA
&&
.PRELIMINARY POINT TEMPS/POPS...
ATHENS 57 34 58 37 / 40 10 0 5
ATLANTA 55 36 57 40 / 40 10 0 5
BLAIRSVILLE 49 31 53 32 / 40 10 0 10
CARTERSVILLE 53 34 57 34 / 40 10 0 5
COLUMBUS 59 38 60 40 / 40 10 0 5
GAINESVILLE 54 34 55 38 / 40 10 0 5
MACON 61 38 60 36 / 40 20 0 5
ROME 53 34 57 32 / 40 10 0 10
PEACHTREE CITY 57 33 57 36 / 40 10 0 5
VIDALIA 70 43 61 41 / 40 30 0 10
&&
.FFC WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
AREA FORECAST DISCUSSION...UPDATED
NWS JACKSON KY
932 AM EST WED FEB 13 2013
.UPDATE...
ISSUED AT 931 AM EST WED FEB 13 2013
LIGHT...INTERMITTENT RAIN WITH TEMPS AROUND 40 COVERING MOST OF THE
CWFA. LOWER TEMPS AND LIGHT SNOW TO OUR WEST. UPDATED GRIDS TO
INDICATE LATE MORNING HIGH TEMPS AND THEN FALLING TEMPS THIS
AFTERNOON. RAIN SHOULD CHANGE TO SNOW AND THERE MAY BE A FEW BANDS OF
SNOW TO ACCUMULATE BUT THE GROUND AND ESPECIALLY THE ROADS ARE TOO
WARM TO SUPPORT OTHER THAN MOMENTARY ACCUMULATIONS. BY THE TIME THE
COLD AIR ARRIVES AND THE RAIN CHANGES TO ALL SNOW...MOST OF THE
MOISTURE WILL BE EAST OF THE AREA AND JUST A FEW FLURRIES WILL REMAIN
FOR ALL BUT THE HIGHER ELEVATIONS NEAR THE VA/W VA BORDER. UPDATED
GRIDS AND ZONES WITH LATEST INFORMATION.
UPDATE ISSUED AT 658 AM EST WED FEB 13 2013
CURRENT CONDITIONS ACROSS EASTERN KENTUCKY HAVE PRECIP MOVING INTO
THE AREA WITH RAIN REACHING THE GROUND IN THE SOUTH. HAVE UPDATED TO
FINE TUNE POPS AND ANY COOLING EFFECTS TO TEMPS FROM THE RAINFALL.
UPSTREAM...IT SEEMS THE BAND SETTING UP WILL STAY JUST NORTH SO WILL
KEEP CURRENT SNOWFALL FORECAST IN PLACE. ONLY CONCERN RIGHT NOW IS
THE COOLING EFFECTS AND SURFACE TEMPS OVER THE SOUTH AS SOME REPORTS
OF MODERATE RAIN POSSIBLY REALLY COOLING SURFACE TEMPS. WILL BANK ON
SURFACE TEMPS STAYING WARM ENOUGH THROUGH THE EARLY AFTERNOON BEFORE
THE COLD AIR FINALLY CHANGES THE RAIN OVER THIS AFTERNOON.
ALSO...MODEL SOUNDINGS CONTINUE TO SHOW DRY AIR AIR AT THE 10 DEGREE
CELSIUS TEMPS AND HIGHER SO WILL KEEP THE INCH OR SNOW FORECAST NORTH
OF THE MOUNTAIN PARKWAY AND IN THE HIGHEST ELEVATIONS SO NO NEW ZFP
WAS NEEDED.
&&
.SHORT TERM...(TODAY THROUGH THURSDAY)
ISSUED AT 423 AM EST WED FEB 13 2013
CURRENT 09Z ANALYSIS ACROSS THE AREA HAS WIDESPREAD CLOUD COVER OVER
EASTERN KENTUCKY WITH PRECIP ALONG THE TN AND KY BORDER IN SOUTH
CENTRAL KY DEVELOPING AND MOVING INTO THE AREA. CURRENT TEMPERATURES
ACROSS THE SOUTHERN PORTION OF THE AREA ARE IN THE LOW 40S TO UPPER
30S. HOWEVER SURFACE TEMPS ALONG AND NORTH OF THE MOUNTAIN PARKWAY
ARE COLD ENOUGH TO SUSTAIN SOME SNOWFALL AS THE PRECIP WILL CREEP
INTO THE NORTHERN PORTION OF THE CWA BY 12Z. MET SAT DATA CURRENTLY
SHOWS THE DEVELOPING SURFACE LOW OVER THE LOWER TN VALLEY AND
SHIFTING OFF TO THE NORTHEAST. THE UPPER LOW IS LOCATED OVER SOUTHERN
IL MOVING TO THE EAST NORTHEAST. CURRENT SHORT TERM MODELS INDICATE A
BAND OF HEAVY PRECIP SETTING UP. THE CHALLENGE HERE IS THE LOCATION
OF THE DEVELOPMENT. BOTH THE NAM AND GFS HAVE INDICATED A BAND OF
HEAVIER PRECIP JUST SOUTH OF THE OH RIVER AND ALSO ANOTHER BAND
GOING THROUGH CENTRAL EASTERN KY. THE HI RES HRRR ALSO SHOWS THIS BUT
WITH THE SOUTHERN BAND NOT AS INTENSE. BASED ON CURRENT WV SHOWING
MID LEVEL MOISTURE AND ADVECTING TOWARD THE UPPER OH VALLEY...HAVE
GONE WITH THE BLUEGRASS AND LOCATIONS NORTH OF THE MOUNTAIN PARKWAY TO
RECEIVE UP TO AN INCH OF SNOWFALL. CURRENT THOUGH IS WITH THE
SOUTHEAST KY STILL QUITE WARMER THAN THE NORTH LOCATIONS...THE BAND
INDICATED THROUGH THE CENTRAL PORTION OF EAST KY...WILL MAINLY BE A
RAIN PRODUCER WITH THE BEST CHANCE FOR ACCUMULATING SNOW ION THE
HIGHER TERRAIN ALONG THE VA BORDER. AS WELL...NAM MODEL SOUNDINGS
STILL SHOW A POOR DENDRITE GROWTH ZONE THROUGH MUCH OF THE
EVENT...LOCATED FROM THE JKL POINT AND SOUTH.
BASED ON ALL THESE FACTORS...HAVE KEPT THE SPS GOING WITH THE INCH
POSSIBLE NORTH OF THE MOUNTAIN PARKWAY AND IN THE HIGHER TERRAIN
ALONG THE VA BORDER. IF THE BAND IN THE NORTH DOES SLIDE SOUTH A
BIT...THE BLUE GRASS COUNTIES WILL QUICKLY REACH ADVISORY CRITERIA.
FOR THE REST OF THE SHORT TERM...A PROGRESSIVE PATTERN REMAINS...SUCH
THAT...LOCATIONS THAT FINALLY BECOME COLD ENOUGH TO SUPPORT SNOW THIS
EVENING AND TONIGHT...MUCH OF THE MOISTURE WILL BE OUT OF THE AREA
WITH A FEW FLURRIES POSSIBLE. THE PATTERN WILL ALLOW A BRIEF STAY FOR
THIS COLDER AIR MASS AS THURSDAY HIGH TEMPS WILL QUICKLY WARM INTO
THE UPPER 40S...MELTING ANY SNOW THAT FALLS TODAY AND TONIGHT.
.LONG TERM...(THURSDAY NIGHT THROUGH TUESDAY)
ISSUED AT 341 AM EST WED FEB 13 2013
THE MODEL START OFF IN FAIRLY GOOD AGREEMENT WITH AN UPPER TROUGH
EXTENDING ACROSS THE MIDWEST. THIS UPPER TROUGH WILL PUSH A WEAK
FRONT ACROSS THE AREA ON FRIDAY BRINGING INITIALLY A MIX OF RAIN AND
SNOW IN THE MORNING AND THEN TURNING TO ALL RAIN AS IT WARMS UP A
LITTLE IN THE AFTERNOON AND THEN A MIX OF RAIN AND SNOW AGAIN IN THE
EVENING WHEN THINGS COOL OFF AGAIN. AT WORST...A DUSTING OF SNOW IS
EXPECTED WITH THIS SYSTEM. SOME FLURRIES OR VERY LIGHT SNOW IS
POSSIBLE ON SATURDAY AS THE UPPER TROUGH MOVES THROUGH THE AREA.
THIS IS ALSO WHERE THE MODELS REALLY BEGIN TO DIVERGE WITH THE ECMWF
ABOUT 12 HOURS SLOWER WITH THE UPPER TROUGH PASSAGE. ALSO THE ECMWF
HAS A MUCH SHARPER AND DEEPER UPPER TROUGH THAN THE GFS. THE MODELS
THEN GET INTO BETTER AGREEMENT WITH A MORE ZONAL PATTERN DEVELOPING
ACROSS THE US. THE NEXT SYSTEM TO MOVE ACROSS EASTERN KENTUCKY WILL
BE ON TUESDAY. HERE THE ECMWF IS THE FASTER OF THE TWO SYSTEMS.
DECIDED TO GO WITH THE FASTER ECMWF FOR THE TUESDAY SYSTEM. THE
PATTERN THUS REMAINS ACTIVE...HOWEVER NO MAJOR SYSTEMS WITH BIG
IMPACT ARE EXPECTED. FOR THE TEMPERATES...GENERALLY NUDGED THE MODEL
BLEND TOWARD THE NEW AND GENERALLY WARMER ECMWF RAW DATA FOR THE
TEMPERATURE FORECAST.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z THURSDAY MORNING)
ISSUED AT 658 AM EST WED FEB 13 2013
WITH STILL A DRY LOWER LAYER TO OVERCOME...MVFR AND IFR CEILINGS WILL
HOLD OFF TILL 14Z TO 15Z. PRECIP WILL FALL THROUGH THE MORNING ACROSS
THE AREA LOWERING VIS TO MVFR AND IFR CONDITIONS ALONG WITH CEILINGS
REMAINING OVER THE AREA THROUGH THE REST OF THE TAF PERIOD. PRECIP
SHOULD END ACROSS EASTERN KENTUCKY BY 03Z WITH CEILINGS REMAINING
THROUGH THE REST OF THE TAF PERIOD.
&&
.JKL WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...DUSTY
SHORT TERM...SHALLENBERGER
LONG TERM...JJ
AVIATION...SHALLENBERGER
AREA FORECAST DISCUSSION
NWS LOUISVILLE KY
703 AM EST WED FEB 13 2013
.Forecast Update...
Issued at 655 AM EST Wed Feb 13 2013
We`re starting to see a rain/snow mix over southern Indiana and
portions of north central KY this morning including the Louisville
metro area. Updated the forecast to extend categorical POPs farther
north into southern Indiana with up to 1 inch of slushy accums
possible there as well. Radar imagery indicates moisture setting up
farther north than previously forecast. Latest RAP run has a good
handle on this. Will update and continue the SPS for this event.
&&
.Short Term (Now through Thursday)...
Issued at 325 AM EST Wed Feb 13 2013
...Light Slushy Snow Accumulations Possible Today...
As of 745Z, an upper trough was over MO with sfc low pressure over
the Gulf States. Precipitation associated with this system
stretched from western KY to eastern OK as of 745Z with rain
observed over most areas ESE of the upper trough and snow or a
rain/snow mix observed over portions of OK/MO/AR in the upper level
trough. The 6Z NAM12 and last few RAP runs seem to have the best
handle on the area of precipitation and general schematic of ptype.
Overall timing of the best precip and forcing seems to be a little
earlier than previously thought. Looks like the best dynamics and
precip should fall over our region between 12-18Z. Also, the latest
runs of the NAM and RAP have moved the best band of moderate to
heavy precip...probably a heavy wet snow as observed out in MO...to
the north. According to these models, the best snow band in which
we could see 1-2 inches of wet, slushy snow would be in a corridor
along the Ohio River to along the Western KY and Bluegrass
Parkways. Other areas over southern Indiana and south central KY
may see a brief mix of rain/snow...enough to create a dusting to a
half inch before quickly melting off. There is still some
uncertainty in where the band of moderate to heavy snow will set up
so stay tuned to morning forecast updates. Also, because of the
uncertainty, will continue with the SPS product instead of going
with an advisory although one may be needed later this morning.
So for today expect light rain to overspread the area before sunrise
with possibly some snow grains mixing in over southern Indiana and
northern KY at precip onset due to a deeper cold layer. After
sunrise we`ll start to see colder air filter in with the upper
trough causing precip to change over to a rain/snow mix and then
probably all snow for a time over southern Indiana and central KY.
The morning hours after sunrise through early afternoon will be the
best time for a period of moderate to heavy wet snow resulting in
slushy snow accumulations as high as 1-2 inches over north central
KY. This period of wintry precip may cause some travel issues.
We`ll continue to see a early afternoon before precip exits to our
east by late afternoon/early evening. Once snow comes to an end
over any location, quick melting can be expected as sfc temps are
expected to be above freezing today. In fact, most locations will
still top out in the upper 30s to lower 40s this afternoon despite
any morning/early afternoon snow.
For tonight and Thurs, expect dry conditions with partly cloudy
skies. Low temps will be in the upper 20s to lower 30s tonight. An
upper level trough and cold front will approach the region by Thurs
evening. Ahead of the trough, though, Thurs will be quite warm with
a strong southerly flow in place. High temps Thurs should be in the
low to mid 50s.
.Long Term (Thursday Night - Tuesday)...
Issued at 320 AM EST Wed Feb 13 2013
...A few shots for snow showers followed by a warm up and another
strong storm system early next week...
A lead shortwave will move across the Great Lakes on Thursday night,
with the associated surface system dragging a moisture starved cold
frontal boundary through the region. A secondary shortwave will
quickly move across the Ohio Valley on Friday as overall trough
envelopes the eastern CONUS. Friday looks to be the best setup for
some snow showers across the area as enough deep moisture combines
with steep low and mid level lapse rates, and an upslope surface
component. Soundings for this time period do show some convective
instability with saturation well into the -10 -20 C range across
northern portions of the CWA. Surface temperatures may squeak into
the mid and upper 30s on Friday, however thermal profile will be
easily cold enough for all snow showers below 40 degrees, some of
which could produce bursts of heavy snow and gusty winds.
At this point, best location for snow looks to be across southern
Indiana and north central Kentucky. As was mentioned in the previous
forecast, these snow showers have the potential to cause an impact
across the region with very light but quick accumulations. This setup
will have to be monitored.
We should see a lull in the activity on Friday night with subsidence
behind the quickly departing shortwave. Temperatures will be much
cooler with lows dropping into the mid 20s. By Saturday, confidence
is low as to exact placement of trough axis. Models are still having
trouble with the timing/placement of individual waves and the
overall progression of the east CONUS trough amplification. Have
continued the trend of a drier Saturday as a GFS/GEM/GFS ensemble
mean consensus agree on an eastern solution with subsidence aloft
already in place across the Ohio Valley on Saturday. The less
consistent ECMWF still holds the axis to the west. Will only mention
a slight chance of a snow shower east of I-65 to account for this.
May be able to go completely dry for Saturday with the next set of
model runs. Temperatures will be cooler than Friday with highs only
topping out in the low and mid 30s.
Saturday night/Sunday morning will be the coldest of the period as
lows drop to around 20. Radiational cooling conditions will not be
optimal as surface winds stay up a bit and some upper level clouds
look to stream overhead. Therefore, cannot drop low too near dew
points that will be in the lower teens. May be able to decouple a
few of the coolest spots into the upper teens but the upper level
cloud cover should mostly mitigate this.
Saturday night through most of Monday should be dry as surface high
pressure holds over the area and weak upper level ridging holds.
Sunday will begin the warming trend with highs warming into the mid
30s to low 40s. Highs on Monday will be much milder with a return of
southerly flow. The mercury should rebound to the low 50s in most
spots.
By Monday afternoon we will begin to focus on the next storm system
that looks to impact the area through Tuesday. This system will
develop as a lee surface low intensifies ahead of a digging trough
over the central Plains. At this point the low looks to move from
the southern Plains, northeastward either into the Ohio Valley or
just north to the lower Great Lakes through Tuesday morning. This
warmer solution would bring overrunning rain showers to the area
late Monday afternoon, with more widespread rain moving into the
area Monday night and early Tuesday. Temperatures will likely crash
quickly behind the system on Tuesday afternoon as sharp trough moves
through and may eventually have to mention rain changing to snow.
Will stick with all rain for now as it is too early to mention these
details, especially with the low track in question. Will also leave
any thunder mention out of the forecast with the bulk of the
precipitation as any moisture return/instability would be limited by
short duration of southerly flow. This system will have to be
watched however, as a more northerly solution or deeper sfc low
would change the instability picture. Also, chose to disregard the
more southern solution offered by the operational ECMWF. This seems
to be the outlier, with a general consensus between the GFS/GEM/GFS
ensemble mean/ECMWF ensemble mean of a northern solution.
&&
.Aviation (12Z TAF Issuance)...
Issued at 605 AM EST Wed Feb 13 2013
An upper level trough will pass through the area today with a sfc
low pressure passing to our south. Precipitation associated with
this weather system has already begun to spread northward into
central KY this morning. At the beginning of TAF time, it should be
raining near all TAF sites with SDF/LEX rains being more
intermittent showers until deeper moisture overtakes the low level
dry layer. After sunrise, good forcing will enter the region
causing steady moderate banded precip over the region. It`s hard to
say whether a moderate band will affect the TAF sites, but at least
feel confident enough to include lower MVFR conditions this morning
through early afternoon as the heavier precip moves through the
region. Some IFR cigs may be possible in some of the heavier bands
of precip especially near BWG but will not include in the TAF at
this time as confidence is low. Rain is expected to be the
predominant precip type for BWG, however, SDF/LEX could see a RASN
mix in a moderate band. A RASN mix isn`t out of the realm of
possibilities for BWG either, but seems most likely at SDF/LEX at
this time. Will need to adjust as the precip bands set up this
morning and move closer to our area. By mid to late afternoon,
precip should move east of the TAF sites with conditions returning
to high end MVFR and then VFR by this evening.
Winds will be predominantly NNE as the weather system moves through
the area this morning through mid afternoon. Winds will strengthen
throughout the day likely exceeding 7kt at times. Winds will shift
to the WNW behind this system by this evening.
NAM model soundings indicate a layer of low level moisture for
tomorrow morning which could indicate a light fog or low cigs. Will
not place flight restrictions at the end of the TAFs for now, but it
will be something to investigate further.
&&
.LMK WATCHES/WARNINGS/ADVISORIES...
IN...NONE.
KY...NONE.
$$
Update...........AMS
Short Term.......AMS
Long Term........BJS
Aviation.........AMS
AREA FORECAST DISCUSSION
NWS JACKSON KY
658 AM EST WED FEB 13 2013
.UPDATE...
ISSUED AT 658 AM EST WED FEB 13 2013
CURRENT CONDITIONS ACROSS EASTERN KENTUCKY HAVE PRECIP MOVING INTO
THE AREA WITH RAIN REACHING THE GROUND IN THE SOUTH. HAVE UPDATED TO
FINE TUNE POPS AND ANY COOLING EFFECTS TO TEMPS FROM THE RAINFALL.
UPSTREAM...IT SEEMS THE BAND SETTING UP WILL STAY JUST NORTH SO WILL
KEEP CURRENT SNOWFALL FORECAST IN PLACE. ONLY CONCERN RIGHT NOW IS
THE COOLING EFFECTS AND SURFACE TEMPS OVER THE SOUTH AS SOME REPORTS
OF MODERATE RAIN POSSIBLY REALLY COOLING SURFACE TEMPS. WILL BANK ON
SURFACE TEMPS STAYING WARM ENOUGH THROUGH THE EARLY AFTERNOON BEFORE
THE COLD AIR FINALLY CHANGES THE RAIN OVER THIS AFTERNOON.
ALSO...MODEL SOUNDINGS CONTINUE TO SHOW DRY AIR AIR AT THE 10 DEGREE
CELSIUS TEMPS AND HIGHER SO WILL KEEP THE INCH OR SNOW FORECAST NORTH
OF THE MOUNTAIN PARKWAY AND IN THE HIGHEST ELEVATIONS SO NO NEW ZFP
WAS NEEDED.
&&
.SHORT TERM...(TODAY THROUGH THURSDAY)
ISSUED AT 423 AM EST WED FEB 13 2013
CURRENT 09Z ANALYSIS ACROSS THE AREA HAS WIDESPREAD CLOUD COVER OVER
EASTERN KENTUCKY WITH PRECIP ALONG THE TN AND KY BORDER IN SOUTH
CENTRAL KY DEVELOPING AND MOVING INTO THE AREA. CURRENT TEMPERATURES
ACROSS THE SOUTHERN PORTION OF THE AREA ARE IN THE LOW 40S TO UPPER
30S. HOWEVER SURFACE TEMPS ALONG AND NORTH OF THE MOUNTAIN PARKWAY
ARE COLD ENOUGH TO SUSTAIN SOME SNOWFALL AS THE PRECIP WILL CREEP
INTO THE NORTHERN PORTION OF THE CWA BY 12Z. MET SAT DATA CURRENTLY
SHOWS THE DEVELOPING SURFACE LOW OVER THE LOWER TN VALLEY AND
SHIFTING OFF TO THE NORTHEAST. THE UPPER LOW IS LOCATED OVER SOUTHERN
IL MOVING TO THE EAST NORTHEAST. CURRENT SHORT TERM MODELS INDICATE A
BAND OF HEAVY PRECIP SETTING UP. THE CHALLENGE HERE IS THE LOCATION
OF THE DEVELOPMENT. BOTH THE NAM AND GFS HAVE INDICATED A BAND OF
HEAVIER PRECIP JUST SOUTH OF THE OH RIVER AND ALSO ANOTHER BAND
GOING THROUGH CENTRAL EASTERN KY. THE HI RES HRRR ALSO SHOWS THIS BUT
WITH THE SOUTHERN BAND NOT AS INTENSE. BASED ON CURRENT WV SHOWING
MID LEVEL MOISTURE AND ADVECTING TOWARD THE UPPER OH VALLEY...HAVE
GONE WITH THE BLUEGRASS AND LOCATIONS NORTH OF THE MOUNTAIN PARKWAY TO
RECEIVE UP TO AN INCH OF SNOWFALL. CURRENT THOUGH IS WITH THE
SOUTHEAST KY STILL QUITE WARMER THAN THE NORTH LOCATIONS...THE BAND
INDICATED THROUGH THE CENTRAL PORTION OF EAST KY...WILL MAINLY BE A
RAIN PRODUCER WITH THE BEST CHANCE FOR ACCUMULATING SNOW ION THE
HIGHER TERRAIN ALONG THE VA BORDER. AS WELL...NAM MODEL SOUNDINGS
STILL SHOW A POOR DENDRITE GROWTH ZONE THROUGH MUCH OF THE
EVENT...LOCATED FROM THE JKL POINT AND SOUTH.
BASED ON ALL THESE FACTORS...HAVE KEPT THE SPS GOING WITH THE INCH
POSSIBLE NORTH OF THE MOUNTAIN PARKWAY AND IN THE HIGHER TERRAIN
ALONG THE VA BORDER. IF THE BAND IN THE NORTH DOES SLIDE SOUTH A
BIT...THE BLUE GRASS COUNTIES WILL QUICKLY REACH ADVISORY CRITERIA.
FOR THE REST OF THE SHORT TERM...A PROGRESSIVE PATTERN REMAINS...SUCH
THAT...LOCATIONS THAT FINALLY BECOME COLD ENOUGH TO SUPPORT SNOW THIS
EVENING AND TONIGHT...MUCH OF THE MOISTURE WILL BE OUT OF THE AREA
WITH A FEW FLURRIES POSSIBLE. THE PATTERN WILL ALLOW A BRIEF STAY FOR
THIS COLDER AIR MASS AS THURSDAY HIGH TEMPS WILL QUICKLY WARM INTO
THE UPPER 40S...MELTING ANY SNOW THAT FALLS TODAY AND TONIGHT.
.LONG TERM...(THURSDAY NIGHT THROUGH TUESDAY)
ISSUED AT 341 AM EST WED FEB 13 2013
THE MODEL START OFF IN FAIRLY GOOD AGREEMENT WITH AN UPPER TROUGH
EXTENDING ACROSS THE MIDWEST. THIS UPPER TROUGH WILL PUSH A WEAK
FRONT ACROSS THE AREA ON FRIDAY BRINGING INITIALLY A MIX OF RAIN AND
SNOW IN THE MORNING AND THEN TURNING TO ALL RAIN AS IT WARMS UP A
LITTLE IN THE AFTERNOON AND THEN A MIX OF RAIN AND SNOW AGAIN IN THE
EVENING WHEN THINGS COOL OFF AGAIN. AT WORST...A DUSTING OF SNOW IS
EXPECTED WITH THIS SYSTEM. SOME FLURRIES OR VERY LIGHT SNOW IS
POSSIBLE ON SATURDAY AS THE UPPER TROUGH MOVES THROUGH THE AREA.
THIS IS ALSO WHERE THE MODELS REALLY BEGIN TO DIVERGE WITH THE ECMWF
ABOUT 12 HOURS SLOWER WITH THE UPPER TROUGH PASSAGE. ALSO THE ECMWF
HAS A MUCH SHARPER AND DEEPER UPPER TROUGH THAN THE GFS. THE MODELS
THEN GET INTO BETTER AGREEMENT WITH A MORE ZONAL PATTERN DEVELOPING
ACROSS THE US. THE NEXT SYSTEM TO MOVE ACROSS EASTERN KENTUCKY WILL
BE ON TUESDAY. HERE THE ECMWF IS THE FASTER OF THE TWO SYSTEMS.
DECIDED TO GO WITH THE FASTER ECMWF FOR THE TUESDAY SYSTEM. THE
PATTERN THUS REMAINS ACTIVE...HOWEVER NO MAJOR SYSTEMS WITH BIG
IMPACT ARE EXPECTED. FOR THE TEMPERATES...GENERALLY NUDGED THE MODEL
BLEND TOWARD THE NEW AND GENERALLY WARMER ECMWF RAW DATA FOR THE
TEMPERATURE FORECAST.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z THURSDAY MORNING)
ISSUED AT 658 AM EST WED FEB 13 2013
WITH STILL A DRY LOWER LAYER TO OVERCOME...MVFR AND IFR CEILINGS WILL
HOLD OFF TILL 14Z TO 15Z. PRECIP WILL FALL THROUGH THE MORNING ACROSS
THE AREA LOWERING VIS TO MVFR AND IFR CONDITIONS ALONG WITH CEILINGS
REMAINING OVER THE AREA THROUGH THE REST OF THE TAF PERIOD. PRECIP
SHOULD END ACROSS EASTERN KENTUCKY BY 03Z WITH CEILINGS REMAINING
THROUGH THE REST OF THE TAF PERIOD.
&&
.JKL WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...SHALLENBERGER
SHORT TERM...SHALLENBERGER
LONG TERM...JJ
AVIATION...SHALLENBERGER
AREA FORECAST DISCUSSION
NWS LOUISVILLE KY
609 AM EST WED FEB 13 2013
...Updated Aviation Discussion...
.Short Term (Now through Thursday)...
Issued at 325 AM EST Wed Feb 13 2013
...Light Slushy Snow Accumulations Possible Today...
As of 745Z, an upper trough was over MO with sfc low pressure over
the Gulf States. Precipitation associated with this system
stretched from western KY to eastern OK as of 745Z with rain
observed over most areas ESE of the upper trough and snow or a
rain/snow mix observed over portions of OK/MO/AR in the upper level
trough. The 6Z NAM12 and last few RAP runs seem to have the best
handle on the area of precipitation and general schematic of ptype.
Overall timing of the best precip and forcing seems to be a little
earlier than previously thought. Looks like the best dynamics and
precip should fall over our region between 12-18Z. Also, the latest
runs of the NAM and RAP have moved the best band of moderate to
heavy precip...probably a heavy wet snow as observed out in MO...to
the north. According to these models, the best snow band in which
we could see 1-2 inches of wet, slushy snow would be in a corridor
along the Ohio River to along the Western KY and Bluegrass
Parkways. Other areas over southern Indiana and south central KY
may see a brief mix of rain/snow...enough to create a dusting to a
half inch before quickly melting off. There is still some
uncertainty in where the band of moderate to heavy snow will set up
so stay tuned to morning forecast updates. Also, because of the
uncertainty, will continue with the SPS product instead of going
with an advisory although one may be needed later this morning.
So for today expect light rain to overspread the area before sunrise
with possibly some snow grains mixing in over southern Indiana and
northern KY at precip onset due to a deeper cold layer. After
sunrise we`ll start to see colder air filter in with the upper
trough causing precip to change over to a rain/snow mix and then
probably all snow for a time over southern Indiana and central KY.
The morning hours after sunrise through early afternoon will be the
best time for a period of moderate to heavy wet snow resulting in
slushy snow accumulations as high as 1-2 inches over north central
KY. This period of wintry precip may cause some travel issues.
We`ll continue to see a early afternoon before precip exits to our
east by late afternoon/early evening. Once snow comes to an end
over any location, quick melting can be expected as sfc temps are
expected to be above freezing today. In fact, most locations will
still top out in the upper 30s to lower 40s this afternoon despite
any morning/early afternoon snow.
For tonight and Thurs, expect dry conditions with partly cloudy
skies. Low temps will be in the upper 20s to lower 30s tonight. An
upper level trough and cold front will approach the region by Thurs
evening. Ahead of the trough, though, Thurs will be quite warm with
a strong southerly flow in place. High temps Thurs should be in the
low to mid 50s.
.Long Term (Thursday Night - Tuesday)...
Issued at 320 AM EST Wed Feb 13 2013
...A few shots for snow showers followed by a warm up and another
strong storm system early next week...
A lead shortwave will move across the Great Lakes on Thursday night,
with the associated surface system dragging a moisture starved cold
frontal boundary through the region. A secondary shortwave will
quickly move across the Ohio Valley on Friday as overall trough
envelopes the eastern CONUS. Friday looks to be the best setup for
some snow showers across the area as enough deep moisture combines
with steep low and mid level lapse rates, and an upslope surface
component. Soundings for this time period do show some convective
instability with saturation well into the -10 -20 C range across
northern portions of the CWA. Surface temperatures may squeak into
the mid and upper 30s on Friday, however thermal profile will be
easily cold enough for all snow showers below 40 degrees, some of
which could produce bursts of heavy snow and gusty winds.
At this point, best location for snow looks to be across southern
Indiana and north central Kentucky. As was mentioned in the previous
forecast, these snow showers have the potential to cause an impact
across the region with very light but quick accumulations. This setup
will have to be monitored.
We should see a lull in the activity on Friday night with subsidence
behind the quickly departing shortwave. Temperatures will be much
cooler with lows dropping into the mid 20s. By Saturday, confidence
is low as to exact placement of trough axis. Models are still having
trouble with the timing/placement of individual waves and the
overall progression of the east CONUS trough amplification. Have
continued the trend of a drier Saturday as a GFS/GEM/GFS ensemble
mean consensus agree on an eastern solution with subsidence aloft
already in place across the Ohio Valley on Saturday. The less
consistent ECMWF still holds the axis to the west. Will only mention
a slight chance of a snow shower east of I-65 to account for this.
May be able to go completely dry for Saturday with the next set of
model runs. Temperatures will be cooler than Friday with highs only
topping out in the low and mid 30s.
Saturday night/Sunday morning will be the coldest of the period as
lows drop to around 20. Radiational cooling conditions will not be
optimal as surface winds stay up a bit and some upper level clouds
look to stream overhead. Therefore, cannot drop low too near dew
points that will be in the lower teens. May be able to decouple a
few of the coolest spots into the upper teens but the upper level
cloud cover should mostly mitigate this.
Saturday night through most of Monday should be dry as surface high
pressure holds over the area and weak upper level ridging holds.
Sunday will begin the warming trend with highs warming into the mid
30s to low 40s. Highs on Monday will be much milder with a return of
southerly flow. The mercury should rebound to the low 50s in most
spots.
By Monday afternoon we will begin to focus on the next storm system
that looks to impact the area through Tuesday. This system will
develop as a lee surface low intensifies ahead of a digging trough
over the central Plains. At this point the low looks to move from
the southern Plains, northeastward either into the Ohio Valley or
just north to the lower Great Lakes through Tuesday morning. This
warmer solution would bring overrunning rain showers to the area
late Monday afternoon, with more widespread rain moving into the
area Monday night and early Tuesday. Temperatures will likely crash
quickly behind the system on Tuesday afternoon as sharp trough moves
through and may eventually have to mention rain changing to snow.
Will stick with all rain for now as it is too early to mention these
details, especially with the low track in question. Will also leave
any thunder mention out of the forecast with the bulk of the
precipitation as any moisture return/instability would be limited by
short duration of southerly flow. This system will have to be
watched however, as a more northerly solution or deeper sfc low
would change the instability picture. Also, chose to disregard the
more southern solution offered by the operational ECMWF. This seems
to be the outlier, with a general consensus between the GFS/GEM/GFS
ensemble mean/ECMWF ensemble mean of a northern solution.
&&
.Aviation (12Z TAF Issuance)...
Issued at 605 AM EST Wed Feb 13 2013
An upper level trough will pass through the area today with a sfc
low pressure passing to our south. Precipitation associated with
this weather system has already begun to spread northward into
central KY this morning. At the beginning of TAF time, it should be
raining near all TAF sites with SDF/LEX rains being more
intermittent showers until deeper moisture overtakes the low level
dry layer. After sunrise, good forcing will enter the region
causing steady moderate banded precip over the region. It`s hard to
say whether a moderate band will affect the TAF sites, but at least
feel confident enough to include lower MVFR conditions this morning
through early afternoon as the heavier precip moves through the
region. Some IFR cigs may be possible in some of the heavier bands
of precip especially near BWG but will not include in the TAF at
this time as confidence is low. Rain is expected to be the
predominant precip type for BWG, however, SDF/LEX could see a RASN
mix in a moderate band. A RASN mix isn`t out of the realm of
possibilities for BWG either, but seems most likely at SDF/LEX at
this time. Will need to adjust as the precip bands set up this
morning and move closer to our area. By mid to late afternoon,
precip should move east of the TAF sites with conditions returning
to high end MVFR and then VFR by this evening.
Winds will be predominantly NNE as the weather system moves through
the area this morning through mid afternoon. Winds will strengthen
throughout the day likely exceeding 7kt at times. Winds will shift
to the WNW behind this system by this evening.
NAM model soundings indicate a layer of low level moisture for
tomorrow morning which could indicate a light fog or low cigs. Will
not place flight restrictions at the end of the TAFs for now, but it
will be something to investigate further.
&&
.LMK WATCHES/WARNINGS/ADVISORIES...
IN...NONE.
KY...NONE.
$$
Short Term.......AMS
Long Term........BJS
Aviation.........AMS
AREA FORECAST DISCUSSION
NWS HASTINGS NE
508 AM CST WED FEB 13 2013
.AVIATION...12Z TAF. CONDITIONS WILL REMAIN AT VFR THROUGH THE
TAF PERIOD. WEST WINDS WILL INCREASE THIS AFTN AHEAD OF AN
APPROACHING FRONTAL BOUNDARY WITH GUSTS OVER 20KTS POSSIBLE. A
COLD FRONTAL BOUNDARY WILL CROSS THE TERMINAL TONIGHT...WITH WINDS
SWITCHING NORTHWESTERLY AND INCREASING...SETTING THE STAGE FOR A WINDY
DAY ON THURSDAY...JUST BEYOND THE TAF PERIOD. PERIODS OF MID/HIGH
CLOUDS WILL CROSS GRI WITH AN OCCASIONAL VFR CEILING.
&&
.PREV DISCUSSION... /ISSUED 453 AM CST WED FEB 13 2013/
SHORT TERM...THROUGH FRIDAY NIGHT. THE MAIN STORIES THROUGH THE
NEXT 72 HOURS INVOLVE A DOWNWARD TREND IN TEMPS AFTER A VERY MILD
ONE TODAY...STRONG NORTHWEST WINDS ON THURSDAY THAT MAY VERY WELL
REQUIRE A WIND ADVISORY ISSUANCE FOR AT LEAST PARTS OF THE
AREA...AND THE POSSIBILITY OF A FEW ROUNDS OF PASSING FLURRIES
DURING THE THURSDAY AFTERNOON THROUGH FRIDAY EVENING TIME FRAME
BUT WITH LITTLE...IF ANY RISK OF ACCUMULATING SNOW. IN
ADDITION...THE COMBINATION OF WARM AIR AND/OR GUSTY WINDS WILL
PROMOTE AT LEAST SOME ELEVATED...BUT LIKELY NON-CRITICAL...FIRE
DANGER IN PARTS OF THE AREA OVER THE NEXT FEW DAYS. THESE FIRE
WEATHER CONCERNS ARE FURTHER DISCUSSED IN THE SEPARATE SECTION
BELOW.
09Z CENTRAL PLAINS OBJECTIVE SURFACE ANALYSIS REVEALED A BROAD
AREA OF HIGH PRESSURE EXTENDING EASTWARD OUT OF THE ROCKIES...WITH
POSSIBLY A VERY SUBTLE TROUGH AXIS EXTENDING FROM FAR SOUTHEAST
NEB INTO SOUTHWEST KS. THIS REGIME WAS PROMOTING FAIRLY STEADY
5-10 MPH WESTERLY BREEZES ACROSS THE MAJORITY OF THE CWA...WHICH
ALONG WITH AN INCOMING BATCH OF HIGH LEVEL CLOUDS SHOULD KEEP MOST
AREAS UP INTO THE 21-25 DEGREE RANGE FOR MORNING LOW TEMPS.
ALOFT...WATER VAPOR IMAGERY AND SHORT TERM MODEL DATA SHOWED THE
CENTRAL PLAINS UNDER NORTH-NORTHWEST FLOW ALOFT...IN BETWEEN THE
SOUTHERN STREAM SHORTWAVE TROUGH ALONG THE MO/AR BORDER...AND A
PARADE OF LOW AMPLITUDE DISTURBANCES ASSOCIATED WITH THE NORTHERN
STREAM JET IN THE SOUTHWEST CANADA/MONTANA AREA. 11-3.9 MICRON
SATELLITE IMAGERY REVEALS CLEAR SKIES OVER MOST OF THE CWA BUT AT
LEAST A THIN LAYER OF HIGH CLOUD WILL BE PASSING OVER MOST OF THE
AREA BETWEEN NOW AND SUNRISE.
TODAY WILL BE THE WELL-ANTICIPATED WARMEST DAY OF THE WEEK FOR THE
ENTIRE CWA. ALOFT...NORTHWEST FLOW WILL PERSIST...WITH ONLY THE
MOST SUBTLE OF MOISTURE-STARVED DISTURBANCES RIDING THROUGH THE
FLOW AS THE AREA REMAINS JUST SOUTH OF A SLIGHTLY STRONGER WAVE
CROSSING THE DAKOTAS THIS AFTERNOON. AS A RESULT...SKY COVER WILL
BE SOMEWHAT VARIABLE TODAY...GENERALLY AVERAGING PARTLY CLOUDY BUT
ALTERNATING BETWEEN PERIODS OF PLENTIFUL SUNSHINE AND PASSING
BATCHES OF MID-HIGH LEVEL CLOUDS. AT THE SURFACE...THE WEST-
NORTHWEST WIND REGIME WILL PERSIST...AND INCREASE IN SPEED IN
RESPONSE TO DEEPENING MIXING TO AT LEAST THE 850-800MB LAYER. AS A
RESULT...UPPED WIND SPEEDS A BIT FROM PREVIOUS FORECAST...AS THE
LATE MORNING-LATE AFTERNOON HOURS WILL FEATURE SUSTAINED SPEEDS AT
LEAST 15-20 MPH WITH SOME GUSTS 25+ MPH. THE DEEP MIXING WILL
COMBINE WITH SLIGHTLY WARMER AIR MOVING IN ALOFT FROM THE WEST TO
RESULT IN HIGH TEMPERATURES WELL INTO THE 50S NEARLY ALL AREAS.
NUDGED UP HIGH TEMPS 2-3 DEGREES FROM PREVIOUS GRIDS IN MOST
AREAS...GETTING MOST PLACES UP BETWEEN 52-55 DEGREES EXCEPT
SLIGHTLY COOLER UPPER 40S MAINLY IN PARTS OF VALLEY COUNTY WHERE
SOME SNOW PACK REMAINS. THESE FORECAST HIGHS ARE RIGHT IN LINE
WITH 07Z RAP HOURLY TEMPS...WHICH HAVE PERFORMED QUITE WELL THE
PAST TWO DAYS.
TONIGHT...HAVE HIGH CONFIDENCE THAT IT WILL REMAIN PRECIP-
FREE...BUT THE LEADING EDGES OF A COLD FRONT WILL START BLEEDING
DOWN FROM THE NORTH...IN RESPONSE TO A PARADE OF NORTHWEST-FLOW
CLIPPER WAVES ALOFT THAT WILL FOCUS ALONG AN AXIS FROM NORTH
DAKOTA-IOWA. SKY COVER WILL REMAIN VARIABLE THROUGH THE NIGHT...AS
STEADY WEST-NORTHWEST BREEZES REMAIN UP BETWEEN 10-20 MPH WITH
SOME HIGHER GUSTS. DESPITE THE WEAK COLD AIR ADVECTION...THESE
WINDS AND PASSING CLOUDS SHOULD HAVE NO PROBLEM KEEPING OVERNIGHT
LOW TEMPERATURES AT LEAST SLIGHTLY WARMER THAN THOSE THIS
MORNING...AND MADE LITTLE CHANGE KEEPING MOST AREAS UP BETWEEN
25-29 DEGREES...AND WOULD NOT BE SURPRISED TO SEE A BIT GREATER
COVERAGE OF LOWS RIGHT AROUND 30 THAN CURRENTLY DEPICTED.
THURSDAY IS UNDOUBTEDLY THE MOST ACTIVE OF THE SHORT TERM
PERIODS...MAINLY DUE TO STRONG WINDS. SINCE 24 HOURS AGO...MOST
MODELS/GUIDANCE HAVE CONTINUED TRENDING UPWARD A BIT WITH
NORTHWESTERLY SPEEDS. FOCUSING FIRST ALOFT...AS THE DAY WEARS ON A
SMALL BUT FAIRLY VIGOROUS MID LEVEL SHORTWAVE TROUGH WILL DROP
SOUTHWARD OUT OF THE DAKOTAS INTO NEB/IA. MEANWHILE AT THE
SURFACE...THE PRESSURE GRADIENT WILL RAMP UP IN RESPONSE TO
INCREASING HIGH PRESSURE EMANATING FROM AN EXPANSIVE NORTHERN
ROCKIES RIDGE. ONCE DIURNAL MIXING KICKS IN AND LOW LEVEL LAPSE
RATES STEEPEN...THE 06Z NAM ADVERTISES MIXING TO DEEPEN WELL UP
INTO THE 800MB TO POSSIBLY 700MB RANGE...WITH AVERAGING WIND
SPEEDS THROUGH THIS MIXED LAYER EASILY SUPPORTING AT LEAST LOW-END
ADVISORY SUSTAINED SPEEDS BETWEEN 30-35 MPH AND GUSTS TO AROUND 45
MPH. WILL ADD THIS STRONG WIND MENTION TO THE HAZARDOUS WEATHER
OUTLOOK...BUT GIVEN IT IS STILL 3 PERIODS AWAY WILL HOLD OFF ON A
WIND ADVISORY FOR NOW...AND GIVE DAY SHIFT ANOTHER LOOK TO
DETERMINE WHETHER AN ADVISORY MAY BE JUSTIFIED FOR ALL 30
COUNTIES...OR MAINLY FOR THE NORTHERN 1/2 OF THE CWA WHICH LOOKS
SLIGHTLY MORE FAVORABLE TO MEET 30+ MPH FOR SEVERAL HOURS VERSUS
SOUTHERN ZONES. THE MAIN WINDOW FOR THE STRONGEST WINDS GENERALLY
LOOKS TO TARGET THE 11 AM-6 PM TIME FRAME. AS FOR PRECIP
CHANCES...HAVE NOTHING MENTIONED DURING THE MORNING...BUT HAVE RE-
INTRODUCED SOME FLURRY CHANCES FOR SOME AREAS NORTH OF I-80 DURING
THE AFTERNOON AS LOW LEVEL STRATUS SWEEPS IN FROM THE NORTH. NOT
THINKING ANYTHING ACCUMULATING AT THIS POINT...WITH BETTER CHANCES
FOR A LIGHT DUSTING FOCUSING JUST NORTH OF OUR AREA. TEMP-
WISE...IF IT WASN/T FOR THE WIND IT REALLY WOULDN/T FEEL TOO
BAD...AND ONLY MADE MINOR TWEAKS TO HIGHS RANGING FROM UPPER 30S
FAR NORTH...LOW 40S CENTRAL AND MID 40S IN KS ZONES.
TAKING A BIT BROADER LOOK AT THE THURSDAY NIGHT THROUGH FRIDAY
NIGHT TIME FRAME...THE BIG PICTURE ALOFT INVOLVES THE CENTRAL
PLAINS REMAINING UNDER NORTHWEST FLOW ALOFT AS A CONTINUING PARADE
OF MID LEVEL SHORTWAVE TROUGHS ROTATING SOUTH-SOUTHEAST OUT OF
CANADA WILL CARVE OUT AN EXPANSIVE LONGWAVE TROUGH THAT WILL
DOMINATE THE EASTERN TWO-THIRDS OF THE NATION. ON THURSDAY
NIGHT...THE INITIAL SHORTWAVE TROUGH WILL PASS JUST SOUTHEAST OF
OUR AREA...WHILE UPSTREAM THE NEXT MAIN ONE ENTERS THE DAKOTAS.
WIND SPEEDS WILL EASE DOWN QUITE A BIT...ESPECIALLY POST-MIDNIGHT
WHEN SPEEDS DECREASE INTO THE 5-10 MPH RANGE. ALTHOUGH SOME AREAS
MAY NOT SEE A SINGLE SNOWFLAKE...OPTED TO KEEP THE GRIDS AS SIMPLE
AS POSSIBLE AND BLANKET THE ENTIRE CWA WITH A SLIGHT CHANCE OF
FLURRIES ALL THE WAY FROM THURSDAY NIGHT THROUGH FRIDAY EVENING
AS THIS PATTERN OFTEN EVOKES SMALL-SCALE PATCHES OR BANDS OF NON-
MEASURABLE SNOW UNDERNEATH THE UPPER JET EXIT REGION...ESPECIALLY
IF SOME OF THE PASSING LOWER STRATUS HAS FAVORABLE DENDRITIC
TEMPERATURES. ALTHOUGH SUPPOSE A SMALL PERCENTAGE OF THE CWA COULD
SEE A LIGHT MEASURABLE DUSTING...ITS TOO EARLY TO DETERMINE WHERE
THIS MIGHT EVEN BE...SO CANNOT JUSTIFY A MEASURABLE 20+ POP
ANYWHERE AT THIS TIME FRAME. WINDS ON FRIDAY WILL REMAIN FROM THE
NORTH-NORTHWEST BUT DO NOT APPEAR NEARLY AS STRONG AS THURSDAY WITH
SUSTAINED SPEEDS GENERALLY TOPPING OUT AROUND 15 MPH. AS FOR
TEMPS...MADE ONLY A SMALL DOWNWARD NUDGE TO THURSDAY NIGHT WITH
MOST AREAS 16-20 DEGREES. FRIDAY STILL SHOULD BE THE COLDEST DAY
OF THE WEEK...BUT ACTUALLY NUDGED UP VALUES A BIT IN SOME AREAS
DUE TO DECENT MIXING POTENTIAL...RANGING FROM MID 30S IN MOST NEB
ZONES TO NEAR 40 IN KS. BY MIDNIGHT FRIDAY NIGHT...ANY FLURRY RISK
SHOULD BE OVER WITH AS THE BACK EDGE OF THE LAST IN A SERIES OF
MID LEVEL SHORTWAVE TROUGHS EXITS THE AREA.
LONG TERM...SATURDAY THROUGH TUESDAY. DRY CONDITIONS ARE FORECAST
THROUGH THE EXTENDED PERIODS. ON SATURDAY...THE PATTERN ALOFT WILL
FEATURE A TROUGH MOVING INTO THE PACIFIC NORTHWEST...RIDGING OVER
THE ROCKIES AND A LONGWAVE TROUGH FROM THE HUDSON BAY SOUTH TO THE
GULF COAST STATES. HEIGHTS WILL RISE ACROSS THE CENTRAL PLAINS OVER
THE WEEKEND AS THE WESTERN RIDGE BUILDS ONTO PLAINS AND THE COLD
AIRMASS ASSOCIATED WITH THE TROUGH TO THE EAST DEPARTS. THE RIDGE
BEGINS TO BREAK DOWN SUNDAY AS AN UPSTREAM TROUGH REACHES THE NORTH
CENTRAL ROCKIES. THIS NEXT TROUGH AND ASSOCIATED COLD FRONT CROSSES
THE CENTRAL PLAINS SUNDAY NIGHT/MONDAY...BRINGING ANOTHER ROUND OF
COLD AIR TO START THE WORKWEEK. TEMPERATURE WISE...TEMPS BEGIN TO
RECOVER ON SATURDAY BEHIND THE UPPER TROUGH...THEN SUNDAY WILL BE
THE WARMEST OF THE EXTENDED PERIODS WITH THE MILD AIRMASS IN PLACE
AHEAD OF THE NEXT APPROACHING COLD FRONT/SYSTEM. HIGHS SUNDAY ARE
LOOKING WELL ABOVE NORMAL IN THE 50S...THEN FOLLOWING COLD FROPA
TEMPS RETURN CLOSER TO FEBRUARY NORMALS FOR MON/TUES.
FIRE WEATHER...ALTHOUGH OUTRIGHT CRITICAL FIRE WEATHER
THRESHOLDS ARE CURRENTLY NOT FORECAST DURING THE NEXT FEW
DAYS...AT LEAST PARTS OF THE CWA BEAR WATCHING FOR SOME ELEVATED
TO NEAR-CRITICAL COMBINATIONS OF WIND AND RELATIVE HUMIDITY.
STARTING OFF TODAY...WEST-NORTHWEST SUSTAINED WIND SPEEDS WILL
AVERAGE 15-20 MPH IN NEARLY ALL AREAS...WITH SPORADIC TO FREQUENT
GUSTS TO 25+ MPH EXPECTED. FORTUNATELY...AFTERNOON RELATIVE
HUMIDITY VALUES ACROSS MOST OF THE ARE FORECAST TO HOLD SLIGHTLY
ABOVE CRITICAL LEVELS IN THE 25-30 PERCENT RANGE. HOWEVER...IT
COULD BE A CLOSE CALL ESPECIALLY IN PARTS OF PHILLIPS/ROOKS/OSBORNE
COUNTIES IN KANSAS...WHERE RH VALUES COULD EDGE A BIT CLOSER TO 20
PERCENT. WILL INTRODUCE AN ELEVATED FIRE DANGER MENTION INTO THE
HAZARDOUS WEATHER OUTLOOK MAINLY FOR THIS AREA. TURNING TO
THURSDAY...AS OUTLINED ABOVE STRONG SUSTAINED WINDS AROUND 30 MPH
OR HIGHER ARE FORECAST ACROSS NEARLY THE ENTIRE CWA.
FORTUNATELY...COOLER TEMPERATURES WILL KEEP AFTERNOON RH
PERCENTAGES ABOVE 30 PERCENT ACROSS NEBRASKA ZONES...BUT KS ZONES
COULD SEE VALUES CREEP DOWN CLOSER TO 25 PERCENT. BOTTOM LINE
IS...WHILE NO MAJOR FIRE DANGER ISSUES ARE ANTICIPATED THESE NEXT
FEW DAYS...SOME CAUTION MAY NEED TAKEN...AND HOURLY RELATIVE
HUMIDITY TRENDS THESE NEXT FEW AFTERNOONS WILL NEED WATCHED
CLOSELY TO MAKE SURE THERE ARE NO SURPRISES DROPPING BELOW 20
PERCENT.
&&
.GID WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
KS...NONE.
&&
$$
SHORT TERM/FIRE WEATHER...PFANNKUCH
LONG TERM/AVIATION...FAY
AREA FORECAST DISCUSSION
NWS HASTINGS NE
453 AM CST WED FEB 13 2013
.SHORT TERM...THROUGH FRIDAY NIGHT. THE MAIN STORIES THROUGH THE
NEXT 72 HOURS INVOLVE A DOWNWARD TREND IN TEMPS AFTER A VERY MILD
ONE TODAY...STRONG NORTHWEST WINDS ON THURSDAY THAT MAY VERY WELL
REQUIRE A WIND ADVISORY ISSUANCE FOR AT LEAST PARTS OF THE
AREA...AND THE POSSIBILITY OF A FEW ROUNDS OF PASSING FLURRIES
DURING THE THURSDAY AFTERNOON THROUGH FRIDAY EVENING TIME FRAME
BUT WITH LITTLE...IF ANY RISK OF ACCUMULATING SNOW. IN
ADDITION...THE COMBINATION OF WARM AIR AND/OR GUSTY WINDS WILL
PROMOTE AT LEAST SOME ELEVATED...BUT LIKELY NON-CRITICAL...FIRE
DANGER IN PARTS OF THE AREA OVER THE NEXT FEW DAYS. THESE FIRE
WEATHER CONCERNS ARE FURTHER DISCUSSED IN THE SEPARATE SECTION
BELOW.
09Z CENTRAL PLAINS OBJECTIVE SURFACE ANALYSIS REVEALED A BROAD
AREA OF HIGH PRESSURE EXTENDING EASTWARD OUT OF THE ROCKIES...WITH
POSSIBLY A VERY SUBTLE TROUGH AXIS EXTENDING FROM FAR SOUTHEAST
NEB INTO SOUTHWEST KS. THIS REGIME WAS PROMOTING FAIRLY STEADY
5-10 MPH WESTERLY BREEZES ACROSS THE MAJORITY OF THE CWA...WHICH
ALONG WITH AN INCOMING BATCH OF HIGH LEVEL CLOUDS SHOULD KEEP MOST
AREAS UP INTO THE 21-25 DEGREE RANGE FOR MORNING LOW TEMPS.
ALOFT...WATER VAPOR IMAGERY AND SHORT TERM MODEL DATA SHOWED THE
CENTRAL PLAINS UNDER NORTH-NORTHWEST FLOW ALOFT...IN BETWEEN THE
SOUTHERN STREAM SHORTWAVE TROUGH ALONG THE MO/AR BORDER...AND A
PARADE OF LOW AMPLITUDE DISTURBANCES ASSOCIATED WITH THE NORTHERN
STREAM JET IN THE SOUTHWEST CANADA/MONTANA AREA. 11-3.9 MICRON
SATELLITE IMAGERY REVEALS CLEAR SKIES OVER MOST OF THE CWA BUT AT
LEAST A THIN LAYER OF HIGH CLOUD WILL BE PASSING OVER MOST OF THE
AREA BETWEEN NOW AND SUNRISE.
TODAY WILL BE THE WELL-ANTICIPATED WARMEST DAY OF THE WEEK FOR THE
ENTIRE CWA. ALOFT...NORTHWEST FLOW WILL PERSIST...WITH ONLY THE
MOST SUBTLE OF MOISTURE-STARVED DISTURBANCES RIDING THROUGH THE
FLOW AS THE AREA REMAINS JUST SOUTH OF A SLIGHTLY STRONGER WAVE
CROSSING THE DAKOTAS THIS AFTERNOON. AS A RESULT...SKY COVER WILL
BE SOMEWHAT VARIABLE TODAY...GENERALLY AVERAGING PARTLY CLOUDY BUT
ALTERNATING BETWEEN PERIODS OF PLENTIFUL SUNSHINE AND PASSING
BATCHES OF MID-HIGH LEVEL CLOUDS. AT THE SURFACE...THE WEST-
NORTHWEST WIND REGIME WILL PERSIST...AND INCREASE IN SPEED IN
RESPONSE TO DEEPENING MIXING TO AT LEAST THE 850-800MB LAYER. AS A
RESULT...UPPED WIND SPEEDS A BIT FROM PREVIOUS FORECAST...AS THE
LATE MORNING-LATE AFTERNOON HOURS WILL FEATURE SUSTAINED SPEEDS AT
LEAST 15-20 MPH WITH SOME GUSTS 25+ MPH. THE DEEP MIXING WILL
COMBINE WITH SLIGHTLY WARMER AIR MOVING IN ALOFT FROM THE WEST TO
RESULT IN HIGH TEMPERATURES WELL INTO THE 50S NEARLY ALL AREAS.
NUDGED UP HIGH TEMPS 2-3 DEGREES FROM PREVIOUS GRIDS IN MOST
AREAS...GETTING MOST PLACES UP BETWEEN 52-55 DEGREES EXCEPT
SLIGHTLY COOLER UPPER 40S MAINLY IN PARTS OF VALLEY COUNTY WHERE
SOME SNOW PACK REMAINS. THESE FORECAST HIGHS ARE RIGHT IN LINE
WITH 07Z RAP HOURLY TEMPS...WHICH HAVE PERFORMED QUITE WELL THE
PAST TWO DAYS.
TONIGHT...HAVE HIGH CONFIDENCE THAT IT WILL REMAIN PRECIP-
FREE...BUT THE LEADING EDGES OF A COLD FRONT WILL START BLEEDING
DOWN FROM THE NORTH...IN RESPONSE TO A PARADE OF NORTHWEST-FLOW
CLIPPER WAVES ALOFT THAT WILL FOCUS ALONG AN AXIS FROM NORTH
DAKOTA-IOWA. SKY COVER WILL REMAIN VARIABLE THROUGH THE NIGHT...AS
STEADY WEST-NORTHWEST BREEZES REMAIN UP BETWEEN 10-20 MPH WITH
SOME HIGHER GUSTS. DESPITE THE WEAK COLD AIR ADVECTION...THESE
WINDS AND PASSING CLOUDS SHOULD HAVE NO PROBLEM KEEPING OVERNIGHT
LOW TEMPERATURES AT LEAST SLIGHTLY WARMER THAN THOSE THIS
MORNING...AND MADE LITTLE CHANGE KEEPING MOST AREAS UP BETWEEN
25-29 DEGREES...AND WOULD NOT BE SURPRISED TO SEE A BIT GREATER
COVERAGE OF LOWS RIGHT AROUND 30 THAN CURRENTLY DEPICTED.
THURSDAY IS UNDOUBTEDLY THE MOST ACTIVE OF THE SHORT TERM
PERIODS...MAINLY DUE TO STRONG WINDS. SINCE 24 HOURS AGO...MOST
MODELS/GUIDANCE HAVE CONTINUED TRENDING UPWARD A BIT WITH
NORTHWESTERLY SPEEDS. FOCUSING FIRST ALOFT...AS THE DAY WEARS ON A
SMALL BUT FAIRLY VIGOROUS MID LEVEL SHORTWAVE TROUGH WILL DROP
SOUTHWARD OUT OF THE DAKOTAS INTO NEB/IA. MEANWHILE AT THE
SURFACE...THE PRESSURE GRADIENT WILL RAMP UP IN RESPONSE TO
INCREASING HIGH PRESSURE EMANATING FROM AN EXPANSIVE NORTHERN
ROCKIES RIDGE. ONCE DIURNAL MIXING KICKS IN AND LOW LEVEL LAPSE
RATES STEEPEN...THE 06Z NAM ADVERTISES MIXING TO DEEPEN WELL UP
INTO THE 800MB TO POSSIBLY 700MB RANGE...WITH AVERAGING WIND
SPEEDS THROUGH THIS MIXED LAYER EASILY SUPPORTING AT LEAST LOW-END
ADVISORY SUSTAINED SPEEDS BETWEEN 30-35 MPH AND GUSTS TO AROUND 45
MPH. WILL ADD THIS STRONG WIND MENTION TO THE HAZARDOUS WEATHER
OUTLOOK...BUT GIVEN IT IS STILL 3 PERIODS AWAY WILL HOLD OFF ON A
WIND ADVISORY FOR NOW...AND GIVE DAY SHIFT ANOTHER LOOK TO
DETERMINE WHETHER AN ADVISORY MAY BE JUSTIFIED FOR ALL 30
COUNTIES...OR MAINLY FOR THE NORTHERN 1/2 OF THE CWA WHICH LOOKS
SLIGHTLY MORE FAVORABLE TO MEET 30+ MPH FOR SEVERAL HOURS VERSUS
SOUTHERN ZONES. THE MAIN WINDOW FOR THE STRONGEST WINDS GENERALLY
LOOKS TO TARGET THE 11 AM-6 PM TIME FRAME. AS FOR PRECIP
CHANCES...HAVE NOTHING MENTIONED DURING THE MORNING...BUT HAVE RE-
INTRODUCED SOME FLURRY CHANCES FOR SOME AREAS NORTH OF I-80 DURING
THE AFTERNOON AS LOW LEVEL STRATUS SWEEPS IN FROM THE NORTH. NOT
THINKING ANYTHING ACCUMULATING AT THIS POINT...WITH BETTER CHANCES
FOR A LIGHT DUSTING FOCUSING JUST NORTH OF OUR AREA. TEMP-
WISE...IF IT WASN/T FOR THE WIND IT REALLY WOULDN/T FEEL TOO
BAD...AND ONLY MADE MINOR TWEAKS TO HIGHS RANGING FROM UPPER 30S
FAR NORTH...LOW 40S CENTRAL AND MID 40S IN KS ZONES.
TAKING A BIT BROADER LOOK AT THE THURSDAY NIGHT THROUGH FRIDAY
NIGHT TIME FRAME...THE BIG PICTURE ALOFT INVOLVES THE CENTRAL
PLAINS REMAINING UNDER NORTHWEST FLOW ALOFT AS A CONTINUING PARADE
OF MID LEVEL SHORTWAVE TROUGHS ROTATING SOUTH-SOUTHEAST OUT OF
CANADA WILL CARVE OUT AN EXPANSIVE LONGWAVE TROUGH THAT WILL
DOMINATE THE EASTERN TWO-THIRDS OF THE NATION. ON THURSDAY
NIGHT...THE INITIAL SHORTWAVE TROUGH WILL PASS JUST SOUTHEAST OF
OUR AREA...WHILE UPSTREAM THE NEXT MAIN ONE ENTERS THE DAKOTAS.
WIND SPEEDS WILL EASE DOWN QUITE A BIT...ESPECIALLY POST-MIDNIGHT
WHEN SPEEDS DECREASE INTO THE 5-10 MPH RANGE. ALTHOUGH SOME AREAS
MAY NOT SEE A SINGLE SNOWFLAKE...OPTED TO KEEP THE GRIDS AS SIMPLE
AS POSSIBLE AND BLANKET THE ENTIRE CWA WITH A SLIGHT CHANCE OF
FLURRIES ALL THE WAY FROM THURSDAY NIGHT THROUGH FRIDAY EVENING
AS THIS PATTERN OFTEN EVOKES SMALL-SCALE PATCHES OR BANDS OF NON-
MEASURABLE SNOW UNDERNEATH THE UPPER JET EXIT REGION...ESPECIALLY
IF SOME OF THE PASSING LOWER STRATUS HAS FAVORABLE DENDRITIC
TEMPERATURES. ALTHOUGH SUPPOSE A SMALL PERCENTAGE OF THE CWA COULD
SEE A LIGHT MEASURABLE DUSTING...ITS TOO EARLY TO DETERMINE WHERE
THIS MIGHT EVEN BE...SO CANNOT JUSTIFY A MEASURABLE 20+ POP
ANYWHERE AT THIS TIME FRAME. WINDS ON FRIDAY WILL REMAIN FROM THE
NORTH-NORTHWEST BUT DO NOT APPEAR NEARLY AS STRONG AS THURSDAY WITH
SUSTAINED SPEEDS GENERALLY TOPPING OUT AROUND 15 MPH. AS FOR
TEMPS...MADE ONLY A SMALL DOWNWARD NUDGE TO THURSDAY NIGHT WITH
MOST AREAS 16-20 DEGREES. FRIDAY STILL SHOULD BE THE COLDEST DAY
OF THE WEEK...BUT ACTUALLY NUDGED UP VALUES A BIT IN SOME AREAS
DUE TO DECENT MIXING POTENTIAL...RANGING FROM MID 30S IN MOST NEB
ZONES TO NEAR 40 IN KS. BY MIDNIGHT FRIDAY NIGHT...ANY FLURRY RISK
SHOULD BE OVER WITH AS THE BACK EDGE OF THE LAST IN A SERIES OF
MID LEVEL SHORTWAVE TROUGHS EXITS THE AREA.
.LONG TERM...SATURDAY THROUGH TUESDAY. DRY CONDITIONS ARE FORECAST
THROUGH THE EXTENDED PERIODS. ON SATURDAY...THE PATTERN ALOFT WILL
FEATURE A TROUGH MOVING INTO THE PACIFIC NORTHWEST...RIDGING OVER
THE ROCKIES AND A LONGWAVE TROUGH FROM THE HUDSON BAY SOUTH TO THE
GULF COAST STATES. HEIGHTS WILL RISE ACROSS THE CENTRAL PLAINS OVER
THE WEEKEND AS THE WESTERN RIDGE BUILDS ONTO PLAINS AND THE COLD
AIRMASS ASSOCIATED WITH THE TROUGH TO THE EAST DEPARTS. THE RIDGE
BEGINS TO BREAK DOWN SUNDAY AS AN UPSTREAM TROUGH REACHES THE NORTH
CENTRAL ROCKIES. THIS NEXT TROUGH AND ASSOCIATED COLD FRONT CROSSES
THE CENTRAL PLAINS SUNDAY NIGHT/MONDAY...BRINGING ANOTHER ROUND OF
COLD AIR TO START THE WORKWEEK. TEMPERATURE WISE...TEMPS BEGIN TO
RECOVER ON SATURDAY BEHIND THE UPPER TROUGH...THEN SUNDAY WILL BE
THE WARMEST OF THE EXTENDED PERIODS WITH THE MILD AIRMASS IN PLACE
AHEAD OF THE NEXT APPROACHING COLD FRONT/SYSTEM. HIGHS SUNDAY ARE
LOOKING WELL ABOVE NORMAL IN THE 50S...THEN FOLLOWING COLD FROPA
TEMPS RETURN CLOSER TO FEBRUARY NORMALS FOR MON/TUES.
&&
.FIRE WEATHER...ALTHOUGH OUTRIGHT CRITICAL FIRE WEATHER
THRESHOLDS ARE CURRENTLY NOT FORECAST DURING THE NEXT FEW
DAYS...AT LEAST PARTS OF THE CWA BEAR WATCHING FOR SOME ELEVATED
TO NEAR-CRITICAL COMBINATIONS OF WIND AND RELATIVE HUMIDITY.
STARTING OFF TODAY...WEST-NORTHWEST SUSTAINED WIND SPEEDS WILL
AVERAGE 15-20 MPH IN NEARLY ALL AREAS...WITH SPORADIC TO FREQUENT
GUSTS TO 25+ MPH EXPECTED. FORTUNATELY...AFTERNOON RELATIVE
HUMIDITY VALUES ACROSS MOST OF THE ARE FORECAST TO HOLD SLIGHTLY
ABOVE CRITICAL LEVELS IN THE 25-30 PERCENT RANGE. HOWEVER...IT
COULD BE A CLOSE CALL ESPECIALLY IN PARTS OF PHILLIPS/ROOKS/OSBORNE
COUNTIES IN KANSAS...WHERE RH VALUES COULD EDGE A BIT CLOSER TO 20
PERCENT. WILL INTRODUCE AN ELEVATED FIRE DANGER MENTION INTO THE
HAZARDOUS WEATHER OUTLOOK MAINLY FOR THIS AREA. TURNING TO
THURSDAY...AS OUTLINED ABOVE STRONG SUSTAINED WINDS AROUND 30 MPH
OR HIGHER ARE FORECAST ACROSS NEARLY THE ENTIRE CWA.
FORTUNATELY...COOLER TEMPERATURES WILL KEEP AFTERNOON RH
PERCENTAGES ABOVE 30 PERCENT ACROSS NEBRASKA ZONES...BUT KS ZONES
COULD SEE VALUES CREEP DOWN CLOSER TO 25 PERCENT. BOTTOM LINE
IS...WHILE NO MAJOR FIRE DANGER ISSUES ARE ANTICIPATED THESE NEXT
FEW DAYS...SOME CAUTION MAY NEED TAKEN...AND HOURLY RELATIVE
HUMIDITY TRENDS THESE NEXT FEW AFTERNOONS WILL NEED WATCHED
CLOSELY TO MAKE SURE THERE ARE NO SURPRISES DROPPING BELOW 20
PERCENT.
&&
.PREV DISCUSSION... /ISSUED 1126 PM CST TUE FEB 12 2013/
AVIATION...06Z TAF. LOOK FOR VFR CONDITIONS THRU THE TAF PERIOD
WITH CLOUDS LIMITED TO MID/HIGH LEVELS. WINDS WILL REMAIN FROM A
WESTERLY DIRECTION BEHIND A SURFACE TROUGH.
&&
.GID WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
KS...NONE.
&&
$$
SHORT TERM/FIRE WEATHER...PFANNKUCH
LONG TERM/AVIATION...FAY
AREA FORECAST DISCUSSION
NWS CLEVELAND OH
949 AM EST WED FEB 13 2013
.SYNOPSIS...
LOW PRESSURE WILL BE CROSSING THE TENNESSEE VALLEY TO THE MID
ATLANTIC TODAY...BUT WEAK HIGH PRESSURE WILL REMAIN OVER THE
LOCAL AREA. LOW PRESSURE FROM WESTERN CANADA WILL CROSS THE GREAT
LAKES THURSDAY AND FRIDAY AND BRING TEMPERATURES BELOW NORMAL FOR
THE WEEKEND. HIGH PRESSURE WILL BE SLOW TO WORK INTO THE CENTRAL
LAKES AND OHIO VALLEY LATE IN THE WEEKEND.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
ONLY MINOR CHANGES HAVE BEEN MADE TO THE GRIDS TO REFLECT CURRENT
CONDITIONS. MODELS HINTING THAT THE CLOUD COVER MAY HANG ON A BIT
LONGER THAN EARLIER THINKING SO WE LOWERED HIGHS BY A DEGREE OR TWO.
PREVIOUS DISCUSSION...
PESKY STRATUS TRAPPED UNDER THE INVERSION HAS BEEN DRIFTING
EASTWARD ALL NIGHT. MOST OF THE AREA WILL BE CLOUDY TO START THE
DAY. AND THESE SHOULD STICK AROUND THROUGH THE
MORNING...SCATTERING THIS AFTERNOON. THE HIGH CLOUDS ASSOCIATED
WITH THE LOW THAT WILL PASS TO OUR SOUTH REMAINS THIN ON THE
NORTHERN EDGE...BUT FOR THE AFTERNOON THEY WILL BE THICKER ACROSS
THE SOUTHERN THIRD TO HALF OF THE AREA...THINNER NORTH. THE BEST
OUTLOOK FOR SUN WOULD BE FOR NW OH/TOLEDO AREA LATER TODAY. AS WE
HAVE HAD THE PAST SEVERAL DAYS...FORECASTING PRECIP TO REMAIN
SOUTH OF THE AREA...AND DRY AIR IN PLACE WINNING OUT. TEMPERATURES
ARE TOUGH TODAY. HAVE STUCK WITH PREVIOUS FORECAST OF UPPER 30S
MOST PLACES. SLIGHTLY COOLER ALONG THE LAKESHORE WITH A LIGHT
NORTH FLOW. OVERALL NOT TOO FAR OFF FROM TUESDAYS HIGHS AND FAIRLY
CLOSE TO GUIDANCE. NO CHANGES FROM EARLIER.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH SATURDAY NIGHT/...
A DISSIPATING TROUGH FROM THE NORTHERN LAKES WILL JUST BRUSH THE
AREA TONIGHT. THIS WILL GIVE US NO TROUBLE OTHER THAN BRINGING A
FEW MID/HIGH CLOUDS ACROSS THE AREA OVERNIGHT. BY MORNING THE
RIDGE ACCESS IS TO OUR EAST AND WE HAVE SET UP A LIGHT RETURN
FLOW.
A LITTLE WEDGE OF WARMER AIR REACHES INTO IND/OH/LOWER MI ON
THURSDAY. WILL STICK WITH H8 TEMPS STILL BELOW ZERO...BUT THAT
WILL AT LEAST GET US WELL INTO THE 40S FOR HIGHS. LEANED TOWARD
THE WARMER GFSBC NUMBERS AS WE SHOULD BE ABLE TO WARM NICELY WITH
MID FEB SUN. WITH THE AFTERNOON THOUGH WE GET ONE FRONT AND SOME
LIFT THAT MAY GENERATE A FEW LIGHT RAIN SHOWERS. STILL HAVE NOT
MOISTENED THE COLUMN SO DID NOT BRING PRECIP CHANCE UP TO 40% OR
SO UNTIL LATE IN THE AFTERNOON. THE BETTER COLD FRONT...SURGE OF
COLDER AIR...AND BETTER MOISTURE ARRIVES LATE THURSDAY NIGHT. SO
LOWS THURSDAY NIGHT STILL REASONABLE IN THE LOWER 30S.
FRIDAY THOUGH WE MAY SEE LITTLE RISE AS THE BRUNT OF THE COLD AIR
ARRIVES. BASE OF TROUGH MOVES INTO THE OHIO VALLEY SO MUCH OF THE
AREA WILL SEE AT LEAST SCATTERED SNOW SHOWERS FRIDAY AND FRIDAY
NIGHT WITH SOME LIGHT ACCUMULATIONS. MORE FREQUENT SNOW SHOWERS
FOR NE OH/NW PA. SNOW SHOWERS LINGER ACROSS NE OH/NW PA INTO
SATURDAY. TEMPS BELOW NORMAL SATURDAY AND EVEN COLDER SATURDAY
NIGHT. LOOKING FOR TEENS SATURDAY NIGHT...WITH SOME SINGLE DIGITS
POSSIBLE. HIGH WILL BE BUILDING IN FROM THE WEST AT THIS POINT AND
MAY HAVE SOME CLEARING WITH IT FOR FDY AREA.
&&
.LONG TERM /SUNDAY THROUGH TUESDAY/...
THE THREAT OF SNOW SHOWERS CONTINUES ON SUNDAY OVER THE SNOW BELT.
THE LAKE AND 850 MB TEMPERATURE DIFFERENCE WILL BE NEAR
18C...HOWEVER...THE AIRMASS IS VERY DRY...CHANCE POPS SEEM
REASONABLE. ELSEWHERE DRY AND PARTLY CLOUDY. HIGH PRESSURE WILL
BE MOVING ACROSS THE FORECAST AREA SUNDAY NIGHT. THE FLOW REMAINS
NORTHWEST BUT WE ARE IN WARM ADVECTION SUNDAY NIGHT. WILL FORECAST A
CHANCE OF FLURRIES FOR THE SNOW BELT.
A STRONG LOW WILL MOVE THROUGH THE WESTERN LAKES MONDAY NIGHT INTO
TUESDAY. MAJOR MODEL DIFFERENCES IN THE STRENGTH...TIMING AND TRACK
OF THE LOW. THIS WILL DETERMINE WHAT THE PRECIPITATION TYPE IS. AT
THIS TIME KEPT IT SNOW MONDAY NIGHT AND RAIN OR SNOW TUESDAY...BUT
THIS WILL HAVE TO BE MONITORED. IF THE GFS IS CORRECT IT COULD BE
RAIN OR FREEZING RAIN MONDAY NIGHT AND MAINLY RAIN ON TUESDAY. USED
A BLEND OF GUIDANCE FOR THE TEMPERATURES BUT CONFIDENCE IS LOW WITH
THE MODEL DISCREPANCIES.
&&
.AVIATION /12Z WEDNESDAY THROUGH SUNDAY/...
HIGH PRESSURE OVER NORTHERN OHIO WILL MOVE EAST TODAY. PLENTY OF
LOW LEVEL MOISTURE STUCK UNDER THE INVERSION WITH MVFR CEILINGS
FAIRLY WIDESPREAD. ANY AREAS THAT ARE SCATTERED WILL BECOME BROKEN
AFTER DAYBREAK. THE QUESTION IS HOW LONG WILL IT TAKE FOR THE LOW
CLOUDS TO DECREASE. THE RUC AND LAMP GUIDANCE ARE TRYING TO
INDICATE IT WILL TAKE ALL DAY FOR NW PA AND A LARGE PART OF NE OH.
THAT SEEMS OVERDONE WITH THE SUN ANGLE GETTING STRONGER AND SOME
SUBSIDENCE. WILL TRY DECREASING THE LOW CLOUDS IN THE AFTERNOON.
FOR THE SOUTHERN PORTION OF THE FORECAST AREA MID CLOUDS WILL
OCCUR BECAUSE OF THE UPPER TROF THAT WAS MOVING THROUGH THE OHIO
VALLEY TODAY. THE CLOUDS WILL DECREASE FOR A TIME LATE THIS
AFTERNOON THROUGH EARLY TONIGHT...THEN THEY WILL INCREASE AHEAD OF
THE NEXT SYSTEM.
OUTLOOK...NON-VFR THURSDAY NIGHT AND FRIDAY SHIFTING TO MAINLY
THE SNOWBELT SATURDAY NIGHT AND SUNDAY.
&&
.MARINE...
OCCASIONAL WEATHER SYSTEMS WILL MOVE THROUGH THE REGION DURING THE
PERIOD. HIGH PRESSURE WILL BE OVER THE LAKE THIS MORNING AND THEN IT
WILL MOVE EAST. A FRONTAL SYSTEM WILL MOVE ACROSS LAKE ERIE THURSDAY
NIGHT. WILL HAVE TO KEEP AN EYE ON THE WINDS...THE COLD ADVECTION IS
SOMEWHAT WEAK. THE GFS MODEL HAS THE 925 MB WINDS UP TO 40
KTS...TRYING TO FLIRT WITH GALE FORCE WINDS. HOWEVER...THE NAM MODEL
AND THE ECMWF ARE MUCH WEAKER. THIS WILL HAVE TO BE MONITORED. AT
THIS TIME KEPT THE WINDS IN THE 15 TO 25 KNOT RANGE. FOR FRIDAY
THROUGH SUNDAY THE FLOW WILL BE NORTHWEST WITH PLENTY OF COLD AIR
BUT THE WINDS WILL STAY WELL BELOW GALE FORCE SPEEDS. HIGH PRESSURE
BUILDS IN BRIEFLY SUNDAY NIGHT AND THEN A STRONG SOUTHERLY FLOW
DEVELOPS.
THE WEATHER SYSTEM FOR MONDAY NIGHT INTO TUESDAY COULD HAVE NEAR
GALE FORCE WINDS DEPENDING ON THE TRACK OF THE LOW.
&&
.CLE WATCHES/WARNINGS/ADVISORIES...
OH...NONE.
PA...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...OUDEMAN
NEAR TERM...MULLEN/OUDEMAN
SHORT TERM...OUDEMAN
LONG TERM...KIELTYKA
AVIATION...KIELTYKA
MARINE...KIELTYKA
AREA FORECAST DISCUSSION
NWS CLEVELAND OH
650 AM EST WED FEB 13 2013
.SYNOPSIS...
LOW PRESSURE WILL BE CROSSING THE TENNESSEE VALLEY TO THE MID
ATLANTIC TODAY...BUT WEAK HIGH PRESSURE WILL REMAIN OVER THE
LOCAL AREA. LOW PRESSURE FROM WESTERN CANADA WILL CROSS THE GREAT
LAKES THURSDAY AND FRIDAY AND BRING TEMPERATURES BELOW NORMAL FOR
THE WEEKEND. HIGH PRESSURE WILL BE SLOW TO WORK INTO THE CENTRAL
LAKES AND OHIO VALLEY LATE IN THE WEEKEND.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
PESKY STRATUS TRAPPED UNDER THE INVERSION HAS BEEN DRIFTING
EASTWARD ALL NIGHT. MOST OF THE AREA WILL BE CLOUDY TO START THE
DAY. AND THESE SHOULD STICK AROUND THROUGH THE
MORNING...SCATTERING THIS AFTERNOON. THE HIGH CLOUDS ASSOCIATED
WITH THE LOW THAT WILL PASS TO OUR SOUTH REMAINS THIN ON THE
NORTHERN EDGE...BUT FOR THE AFTERNOON THEY WILL BE THICKER ACROSS THE
SOUTHERN THIRD TO HALF OF THE AREA...THINNER NORTH. THE BEST
OUTLOOK FOR SUN WOULD BE FOR NW OH/TOLEDO AREA LATER TODAY. AS WE
HAVE HAD THE PAST SEVERAL DAYS...FORECASTING PRECIP TO REMAIN
SOUTH OF THE AREA...AND DRY AIR IN PLACE WINNING OUT. TEMPERATURES
ARE TOUGH TODAY. HAVE STUCK WITH PREVIOUS FORECAST OF UPPER 30S
MOST PLACES. SLIGHTLY COOLER ALONG THE LAKESHORE WITH A LIGHT
NORTH FLOW. OVERALL NOT TOO FAR OFF FROM TUESDAYS HIGHS AND FAIRLY
CLOSE TO GUIDANCE. NO CHANGES FROM EARLIER.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH SATURDAY NIGHT/...
A DISSIPATING TROUGH FROM THE NORTHERN LAKES WILL JUST BRUSH THE
AREA TONIGHT. THIS WILL GIVE US NO TROUBLE OTHER THAN BRINGING A
FEW MID/HIGH CLOUDS ACROSS THE AREA OVERNIGHT. BY MORNING THE
RIDGE ACCESS IS TO OUR EAST AND WE HAVE SET UP A LIGHT RETURN
FLOW.
A LITTLE WEDGE OF WARMER AIR REACHES INTO IND/OH/LOWER MI ON
THURSDAY. WILL STICK WITH H8 TEMPS STILL BELOW ZERO...BUT THAT
WILL AT LEAST GET US WELL INTO THE 40S FOR HIGHS. LEANED TOWARD
THE WARMER GFSBC NUMBERS AS WE SHOULD BE ABLE TO WARM NICELY WITH
MID FEB SUN. WITH THE AFTERNOON THOUGH WE GET ONE FRONT AND SOME
LIFT THAT MAY GENERATE A FEW LIGHT RAIN SHOWERS. STILL HAVE NOT
MOISTENED THE COLUMN SO DID NOT BRING PRECIP CHANCE UP TO 40% OR
SO UNTIL LATE IN THE AFTERNOON. THE BETTER COLD FRONT...SURGE OF
COLDER AIR...AND BETTER MOISTURE ARRIVES LATE THURSDAY NIGHT. SO
LOWS THURSDAY NIGHT STILL REASONABLE IN THE LOWER 30S.
FRIDAY THOUGH WE MAY SEE LITTLE RISE AS THE BRUNT OF THE COLD AIR
ARRIVES. BASE OF TROUGH MOVES INTO THE OHIO VALLEY SO MUCH OF THE
AREA WILL SEE AT LEAST SCATTERED SNOW SHOWERS FRIDAY AND FRIDAY
NIGHT WITH SOME LIGHT ACCUMULATIONS. MORE FREQUENT SNOW SHOWERS
FOR NE OH/NW PA. SNOW SHOWERS LINGER ACROSS NE OH/NW PA INTO
SATURDAY. TEMPS BELOW NORMAL SATURDAY AND EVEN COLDER SATURDAY
NIGHT. LOOKING FOR TEENS SATURDAY NIGHT...WITH SOME SINGLE DIGITS
POSSIBLE. HIGH WILL BE BUILDING IN FROM THE WEST AT THIS POINT AND
MAY HAVE SOME CLEARING WITH IT FOR FDY AREA.
&&
.LONG TERM /SUNDAY THROUGH TUESDAY/...
THE THREAT OF SNOW SHOWERS CONTINUES ON SUNDAY OVER THE SNOW BELT.
THE LAKE AND 850 MB TEMPERATURE DIFFERENCE WILL BE NEAR
18C...HOWEVER...THE AIRMASS IS VERY DRY...CHANCE POPS SEEM
REASONABLE. ELSEWHERE DRY AND PARTLY CLOUDY. HIGH PRESSURE WILL
BE MOVING ACROSS THE FORECAST AREA SUNDAY NIGHT. THE FLOW REMAINS
NORTHWEST BUT WE ARE IN WARM ADVECTION SUNDAY NIGHT. WILL FORECAST A
CHANCE OF FLURRIES FOR THE SNOW BELT.
A STRONG LOW WILL MOVE THROUGH THE WESTERN LAKES MONDAY NIGHT INTO
TUESDAY. MAJOR MODEL DIFFERENCES IN THE STRENGTH...TIMING AND TRACK
OF THE LOW. THIS WILL DETERMINE WHAT THE PRECIPITATION TYPE IS. AT
THIS TIME KEPT IT SNOW MONDAY NIGHT AND RAIN OR SNOW TUESDAY...BUT
THIS WILL HAVE TO BE MONITORED. IF THE GFS IS CORRECT IT COULD BE
RAIN OR FREEZING RAIN MONDAY NIGHT AND MAINLY RAIN ON TUESDAY. USED
A BLEND OF GUIDANCE FOR THE TEMPERATURES BUT CONFIDENCE IS LOW WITH
THE MODEL DISCREPANCIES.
&&
.AVIATION /11Z WEDNESDAY THROUGH SUNDAY/...
HIGH PRESSURE OVER NORTHERN OHIO WILL MOVE EAST TODAY. PLENTY OF
LOW LEVEL MOISTURE STUCK UNDER THE INVERSION WITH MVFR CEILINGS
FAIRLY WIDESPREAD. ANY AREAS THAT ARE SCATTERED WILL BECOME BROKEN
AFTER DAYBREAK. THE QUESTION IS HOW LONG WILL IT TAKE FOR THE LOW
CLOUDS TO DECREASE. THE RUC AND LAMP GUIDANCE ARE TRYING TO
INDICATE IT WILL TAKE ALL DAY FOR NW PA AND A LARGE PART OF NE OH.
THAT SEEMS OVERDONE WITH THE SUN ANGLE GETTING STRONGER AND SOME
SUBSIDENCE. WILL TRY DECREASING THE LOW CLOUDS IN THE AFTERNOON.
FOR THE SOUTHERN PORTION OF THE FORECAST AREA MID CLOUDS WILL
OCCUR BECAUSE OF THE UPPER TROF THAT WAS MOVING THROUGH THE OHIO
VALLEY TODAY. THE CLOUDS WILL DECREASE FOR A TIME LATE THIS
AFTERNOON THROUGH EARLY TONIGHT...THEN THEY WILL INCREASE AHEAD
OF THE NEXT SYSTEM.
OUTLOOK...NON-VFR THURSDAY NIGHT AND FRIDAY SHIFTING TO MAINLY
THE SNOWBELT SATURDAY NIGHT AND SUNDAY.
&&
.MARINE...
OCCASIONAL WEATHER SYSTEMS WILL MOVE THROUGH THE REGION DURING THE
PERIOD. HIGH PRESSURE WILL BE OVER THE LAKE THIS MORNING AND THEN IT
WILL MOVE EAST. A FRONTAL SYSTEM WILL MOVE ACROSS LAKE ERIE THURSDAY
NIGHT. WILL HAVE TO KEEP AN EYE ON THE WINDS...THE COLD ADVECTION IS
SOMEWHAT WEAK. THE GFS MODEL HAS THE 925 MB WINDS UP TO 40
KTS...TRYING TO FLIRT WITH GALE FORCE WINDS. HOWEVER...THE NAM MODEL
AND THE ECMWF ARE MUCH WEAKER. THIS WILL HAVE TO BE MONITORED. AT
THIS TIME KEPT THE WINDS IN THE 15 TO 25 KNOT RANGE. FOR FRIDAY
THROUGH SUNDAY THE FLOW WILL BE NORTHWEST WITH PLENTY OF COLD AIR
BUT THE WINDS WILL STAY WELL BELOW GALE FORCE SPEEDS. HIGH PRESSURE
BUILDS IN BRIEFLY SUNDAY NIGHT AND THEN A STRONG SOUTHERLY FLOW
DEVELOPS.
THE WEATHER SYSTEM FOR MONDAY NIGHT INTO TUESDAY COULD HAVE NEAR
GALE FORCE WINDS DEPENDING ON THE TRACK OF THE LOW.
&&
.CLE WATCHES/WARNINGS/ADVISORIES...
OH...NONE.
PA...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...OUDEMAN
NEAR TERM...OUDEMAN
SHORT TERM...OUDEMAN
LONG TERM...KIELTYKA
AVIATION...KIELTYKA
MARINE...KIELTYKA
AREA FORECAST DISCUSSION
NWS MORRISTOWN TN
938 AM EST WED FEB 13 2013
.DISCUSSION...14Z SURFACE MAP SHOWS LOW PRESSURE NOW CENTERED OVER
SW VA...AND THIS SURFACE LOW SHOULD TRACK NE OVER THE NEXT FEW
HOURS. MAIN AREA OF REMAINING LIGHT RAIN SHOWERS HAS LIFTED NORTH OF
THE SRN 2/3RDS OF THE FORECAST AREA. LATEST RUC MODEL RUN SHOWS GOOD
COVERAGE OF LIGHT RAIN OVER NRN PLATEAU...EXTREME NE TN AND SW VA
THIS AFTERNOON...AS SOME RAIN WRAPS AROUND ON THE BACK SIDE OF THE
EXITING LOW PRESSURE SYSTEM.
PLAN TO UPDATE FORECAST GRIDS SHORTLY...AND I MAY NEED TO LOWER RAIN
CHANCES ACROSS SE TN AND SW NC BY AT LEAST 20 PERCENT. WILL KEEP
HIGH LIKELY TO LOW CATEGORICAL CHANCES OVER NRN PARTS OF E TN INTO
SW VA. HOURLY TEMPS ARE RUNNING VERY CLOSE TO GRIDS AND MAX TEMPS
APPEAR ON TRACK.
&&
.PRELIMINARY POINT TEMPS/POPS...
CHATTANOOGA AIRPORT, TN 52 33 57 35 54 / 70 10 10 10 10
KNOXVILLE MCGHEE TYSON AIRPORT, TN 47 32 54 34 50 / 90 20 10 10 20
OAK RIDGE, TN 47 32 54 33 50 / 90 20 10 10 10
TRI CITIES AIRPORT, TN 46 29 50 31 47 / 90 40 10 10 30
&&
.MRX WATCHES/WARNINGS/ADVISORIES...
NC...NONE.
TN...NONE.
VA...NONE.
&&
$$
TG
AREA FORECAST DISCUSSION
NWS DENVER/BOULDER CO
345 PM MST WED FEB 13 2013
.SHORT TERM...MODERATE NORTHWEST FLOW ALOFT ACROSS REGION. AIRMASS
FAIRLY MOIST BUT RELATIVELY STABLE. MOUNTAIN WEB CAMS SHOWING SOME
LIGHT SNOW ALONG THE CONTINENTAL DIVIDE AS THE PARK AND GORE
RANGES OF WESTERN JACKSON COUNTY. LATEST SNOTEL DATA SUGGESTING
SOME LIGHT ACCUMULATIONS IN ZONE 31 AND PORTIONS OF ZONES 33 AND
34. WINDS HAVE BEEN A BIT GUSTY ACROSS THE HIGHER RIDGES AND ALONG
THE FOOTHILLS. WEST TO NORTHWEST WINDS HAVE ALSO SPREAD ONTO THE
ADJACENT PLAINS AS WELL AS ALONG THE WYOMING AND NEBRASKA BORDERS.
LATEST RAP SHOWS MOISTURE GRADUALLY INCREASING AS LAPSE RATES
INCREASE TO AROUND 7 C/KM BY MIDNIGHT. SHOULD SEE THE SNOW
INCREASE IN COVERAGE OVERNIGHT DUE TO FAVORABLE OROGRAPHICS AND
LAPSE RATES...MAINLY NORTH OF INTERSTATE 70. THERE IS ALSO SOME
INCREASE IN MID LEVEL QG ASCENT AHEAD OF AN APPROACHING SHORTWAVE
WHICH WILL HELP WITH SNOWFALL. SNOW ACCUMULATIONS SHOULD REMAIN
BELOW ADVISORY CRITERIA. ACROSS FOOTHILLS AND PLAINS...GRADIENT
WEAKENS DURING THE EVENING. SHOULD SEE WINDS DECREASE AS A
RESULT...WITH DRAINAGE PATTERN PREVAILING. ON THURSDAY...NORTHWEST
FLOW ALOFT TO CONTINUE. MODELS CONTINUE TO SHOW WEAK SHORTWAVE
MOVING ACROSS WYOMING DURING THE AFTERNOON WITH MID LEVEL ASCENT
MOVING OVER THE AREA. LIGHT SNOW TO BE MORE WIDESPREAD OVER THE
MOUNTAINS SOUTH OF INTERSTATE 70 BY THE AFTERNOON AS OROGRAPHICS
REMAINS FAVORABLE. MODEL CROSS SECTIONS INDICATE VARYING AMOUNTS
OF MOISTURE WITH THE GFS DEEPEST. WILL INCREASE THE POPS AND
COVERAGE OF THE SNOW A BIT BUT KEEP AMOUNTS BELOW ADVISORY
CRITERIA. ACROSS PLAINS...MODELS CONTINUE TO SHOW A FRONT MOVING
SOUTH ACROSS THE AREA DURING THE MORNING...REACHING DENVER AREA
AROUND 15-18Z. NORTHERLY WINDS WITH FRONT BECOMES NORTHEAST DURING
THE AFTERNOON AS SURFACE HIGH PUSHES IN BEHIND FRONT. UPSLOPE NOT
ALL THAT DEEP ACCORDING TO THE CROSS SECTIONS BUT DOES REACH THE
FOOTHILLS. MODELS DO INDICATE SOME LIGHT QPF IN AND NEAR FOOTHILLS
DURING THE AFTERNOON WHEN THE UPSLOPE FLOW OCCURS AND LIFT IS
OVERHEAD. MODEL CONCENSUS SHOWING SNOW AMOUNTS TO BE LESS THAN AN
INCH AND CONFINED TO FOOTHILL AREAS. GFS CONTINUES TO BE
AGRESSIVE WITH THE QPF AND SNOW AMOUNTS. WILL CONTINUE WITH THE
CHANCE POPS FOR THE AFTERNOON MOST AREAS...WITH LIKELY POPS FOR
THE FOOTHILLS. TEMPERATURES TO BE COOLER WITH HIGHS IN THE LOWER
TO MID 30S ACROSS THE PLAINS.
.LONG TERM...NORTHWEST FLOW ALOFT WILL PREVAIL THURSDAY NIGHT AND
FRIDAY WHILE NORTHERLY FLOW EXISTS AT THE LOWER LEVELS.
MOISTURE...LIFT AND INSTABILITY WILL BE LIMITED...BUT ENOUGH WILL
BE PRESENT FOR OCCASIONAL LIGHT SNOW. A WEAK SHORT WILL MOVE
ACROSS THE STATE FRIDAY. IN ADDITION...THE FRONT LEFT QUADRANT OF
THE JET WILL BE OVER NORTHEAST COLORADO FRIDAY. THESE FEATURES
WILL PROVIDE THE LIFT FOR THE LIGHT SNOW. SNOW WILL COME TO END BY
FRIDAY EVENING...IF NOT SOONER AS DRIER AIR SHIFTS OVER THE STATE.
UPPER LEVEL RIDGE WILL MOVE OVER COLORADO SATURDAY. AN UPPER LEVEL
TROUGH WILL DROP INTO THE NORTHERN ROCKIES SUNDAY CAUSING FLOW ALOFT
TO BECOME WESTERLY ON SUNDAY. THIS WILL RESULT IN MILD AND DRY
CONDITIONS FOR THE WEEKEND WITH HIGHS IN THE 50S ACROSS NORTHEAST
COLORADO.
FOR SUNDAY NIGHT AND MONDAY...THE SHORT WAVE TROUGH OVER THE
NORTHERN ROCKIES MAY BRING THE AREA A ROUND OF SNOW AS IT PROGRESSES
EAST. THE GFS BRINGS A PIECE OF ENERGY THROUGH UTAH AND THEN DROPS
IT SOUTHEAST INTO NEW MEXICO. THE ECMWF KEEPS THIS SYSTEM NORTH OF
COLORADO WHICH WOULD RESULT IN DRY CONDITIONS. THE CMC IS SIMILAR TO
THE ECMWF SO WILL KEEP POPS ON THE LOW END FOR THIS SYSTEM. STILL
EXPECT A COLD FRONT AND COOLER AIR TO PUSH THROUGH COLORADO IF THIS
SYSTEMS STAYS NORTH OF THE STATE.
UPPER LEVEL RIDGE WILL QUICKLY MOVE ACROSS THE STATE MONDAY NIGHT
AND BY TUESDAY A SOUTHWEST FLOW ALOFT WILL PREVAIL AS A LARGE TROUGH
CRASHES ONTO THE WEST COAST. THIS SYSTEM WILL SLOWLY MOVE EASTWARD
WEDNESDAY. EXPECT MILD AND DRY CONDITIONS TO PREVAIL WEDNESDAY AHEAD
OF THIS SYSTEM. MAY BE ENOUGH MOISTURE AHEAD OF IT TO PRODUCE LIGHT
MOUNTAIN SNOW. LOOKING BEYOND THE FORECAST TIME FRAME...THE PAST TWO
RUNS OF THE ECMWF SHOW THIS TROUGH MOVING ALONG THE COLORADO/NEW
MEXICO BORDER. IF THIS TYPE OF PATTERN PREVAILS...EASTERN COLORADO
COULD SEE A GOOD SHOT OF SNOW.
&&
.AVIATION...WEST TO NORTHWEST WINDS HAVE PUSHED ACROSS THE AREA
AIRPORTS DURING THE AFTERNOON...WITH GUSTS AROUND 35 KTS AT APA
AND BJC. WINDS SHOWING MORE OF A WESTERLY COMPONENT IN THE PAST
HOUR. MODELS SHOW WINDS WEAKENING BY 01Z AND BECOMING MORE
SOUTHWEST AS DRAINAGE FLOW DEVELOPS. MID AND HIGH LEVEL LEVEL
MOISTURE TO INCREASE OVERNIGHT...CEILINGS TO REMAIN ABOVE 10000
FEET. ON THURSDAY...FRONT TO MOVE ACROSS THE AREA AROUND 15Z WITH
WINDS SHIFTING TO THE NORTH. COULD SEE SOME GUSTS TO 30 KTS.
CEILINGS EXPECTED TO LOWER TO AROUND 6000 FEET AGL BY 18Z. A FEW
SNOW SHOWERS COULD DEVELOP DURING THE MORNING...MAINLY WESTERN
SUBURBS. NORTHEAST WINDS DEVELOP AFTER 18Z WITH MVFR CEILINGS
POSSIBLE. THERE WILL BE A CHANCE OF LIGHT SNOW DURING THE
AFTERNOON...FOR NOW WILL WILL MAINTAIN A PROB30. ANY ACCUMULATIONS
SHOULD BE LESS THAN AN INCH.
&&
.BOU WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...D-L
LONG TERM....MEIER
AVIATION...D-L
AREA FORECAST DISCUSSION
NWS DENVER/BOULDER CO
1009 AM MST WED FEB 13 2013
.UPDATE...
&&
.SHORT TERM...CURRENT FORECASTS LOOK REASONABLE. MOUNTAIN WEB
CAMS INDICATING SOME LIGHT SNOW OVER THE HIGHER PEAKS OF SUMMIT...
GRAND AND BOULDER COUNTIES...WITH PERHAPS SOME LIGHT SNOW ACROSS
THE PARK AND GORE RANGES OF WESTERN JACKSON COUNTY. WINDS HAVE
BEEN STEADILY INCREASING ACROSS THE HIGHER MOUNTAINS AND FOOTHILLS...
LATEST 1500 MB GJT-DEN PRESSURE GRADIENT HAD INCREASED TO 10.40 MB.
GUSTS WERE MAINLY IN THE 40-50 MPH RANGE ALONG THE FOOTHILLS OF
BOULDER...JEFFERSON AND LARIMER COUNTIES. LATEST RAP CROSS SECTIONS
INDICATE CROSS MOUNTAIN FLOW AROUND 35 KTS ALONG WITH A WEAK STABLE
LAYER NEAR THE MOUNTAIN TOP THROUGH THE AFTERNOON. AT THIS TIME...
NOT EXPECTING WINDS TO REACH HIGH WIND CRITERIA. COVERAGE OF SNOW
TO INCREASE AFTER MIDNIGHT WHEN LAPSE RATES INCREASE AND OROGRAPHICS
BECOME MORE FAVORABLE.
.AVIATION...WESTERLIES SLOW TO PUSH INTO THE DENVER AREA...FINALLY
REACHED BJC. RECENTLY DELAYED THE ONSET OF THE WEST WINDS AT DEN
TIL 19Z. THIS STILL SEEMS ON TRACK AS LATEST DEN LLWAS DATA
CONTINUES TO INDICATE MORE OF A SOUTHWEST DIRECTION. LATEST RAP
AND HRRR SHOW WINDS BECOMING NORTHWEST AT DEN AND APA BY 21Z. SO
TREND FOR NORTHWEST WINDS STILL LOOKS REASONABLE...BUT WILL DELAY
THE ONSET FOR THE UPCOMING ISSUANCE. REST OF TAF TRENDS SEEM
REASONABLE...WITH SOUTH TO SOUTHWEST DRAIANGE WINDS DEVELOPING
DURING THE EVENING. COLD FRONT STILL ON TRACK TO MOVE ACROSS THE
AREA AIRPORTS AROUND 15Z THURSDAY...WITH NORTHEAST WINDS
DEVELOPING ALONG WITH LOWER CEILINGS. WILL INCLUDE A PROB30 AT DEN
AFTER 19Z WITH MVFR CEILINGS.
&&
.PREV DISCUSSION... /ISSUED 301 AM MST WED FEB 13 2013/
SHORT TERM...NW FLOW ALOFT WILL INCREASE OVER THE AREA THRU
TONIGHT WITH MOISTURE GRADUALLY INCREASING IN THE MTNS. ALTHOUGH
OROGRAPHIC FLOW WILL BE FAVORABLE LAPSE RATES INITIALLY ARE RATHER
STABLE AND REALLY DO NOT BEGIN TO INCREASE UNTIL AFTER MIDNIGHT.
THUS EXPECT AREAS OF LIGHT SNOW IN THE MTNS MAINLY NORTH OF I-70
WITH SOME INCREASE IN COVERAGE TONIGHT. OVERALL AMOUNTS AT LEAST
THRU TONIGHT STAY BLO ADVISORY CRITERIA. MEANWHILE WITH MTN TOP
STABILITY THRU THE AFTN HOURS WILL SEE GUSTY WINDS OVER THE HIGHER
MTNS AND IN AND NR THE FOOTHILLS. COMPONENT ALONG SPEEDS ARE ON
AVERAGE AROUND 35KTS SO SPEEDS SHOULD STAY BLO HIGH WIND
CRITERIA. WILL ALSO SEE GUSTY WINDS NR THE WY-NE BORDER AS WELL
THRU THE AFTN HOURS. AS FOR TEMPS OVER NERN CO WILL HAVE HIGHS IN
THE 45 TO 50 DEGREE RANGE.
LONG TERM...MODELS HAVE FAIRLY STRONG WEST-NORTHWESTERLY FLOW
ALOFT FOR THE CWA THURSDAY. BY LATE IN THE DAY A WEAK UPPER
TROUGH PUSHES ACROSS WITH STRONG NORTH-NORTHWESTERLY FLOW ALOFT
BEHIND IT. THE STRONG FLOW ALOFT IS PROGGED TO CONTINUE ON
FRIDAY...BUT TO BECOME NORTHERLY IN DIRECTION. THE FLOW ALOFT
BECOMES NORTHWESTERLY AND RELAXES SOMEWHAT BY 12Z SATURDAY
MORNING. THE QG VERTICAL VELOCITY FIELDS SHOW WEAK UPWARD ENERGY
THURSDAY...FOLLOWED BY DOWNWARD MOTION LATE DAY INTO THE
EVENING...THEN ANOTHER BRIEF SHOT OF UPWARD MOTION THROUGH 12Z
FRIDAY MORNING. AFTER THAT IT IS ALL DOWNWARD MOTION INTO THE
WEEKEND. THE UPWARD MOTION LOOKED BETTER ON YESTERDAY`S 00Z RUNS.
THE BOUNDARY LAYER FLOW PROGGS STILL SHOW A BIT OF UPSLOPE OVER
THE PLAINS ON THURSDAY...BUT IT IS GONE THURSDAY NIGHT. BY FRIDAY
MORNING...DOWNSLOPING NORTHWESTERLY FLOW IS PROGGED CONTINUING
THROUGH FRIDAY NIGHT. AGAIN...YESTERDAY`S 00Z RUNS HAD BETTER AND
MORE PROLONGED UPSLOPE FOR PLAINS AND FOOTHILLS. MOISTURE IS ALSO
LESS ACCORDING TO THE CURRENT MODEL RUNS...ESPECIALLY ON THE NAM.
THERE IS SOME MOISTURE AROUND ON THE NAM THURSDAY...BUT IT DECREASES
PRETTY GOOD THURSDAY EVENING. IT INCREASES AGAIN BY 12Z FRIDAY
MORNING...THEN GRADUALLY DECREASES THROUGH THE DAY FRIDAY. THE
GFS HAS A SIMILAR PATTERN ALTHOUGH THE DEPTH OF MOISTURE IS
GREATER THAN ON THE NAM. THE ECMWF IS SOMEWHERE IN BETWEEN THE
TWO. FRIDAY NIGHT DRIES OUT PRETTY GOOD ON ALL THE MODELS. THE QPF
FIELDS SHOW MEASURABLE SNOWFALL FOR THE CWA THURSDAY INTO FRIDAY.
IT IS LESS THAN YESTERDAY`S RUNS INDICATED AND IT IS MOSTLY OVER
THE THE MOUNTAINS. AMOUNTS ARE PRETTY WEAK. SO FOR POPS IN THE
MOUNTAINS...THERE WILL BE SOME OROGRAPHIC HELP AND THERE IS SOME
MOISTURE...SO WILL GO WITH "LIKELY"S THURSDAY AND THURSDAY
NIGHT...THEN DECREASE POPS TO NOTHING DURING THE EVENING FRIDAY.
FOR THE PLAINS...10-40%S SHOULD THURSDAY AFTERNOON INTO MIDDAY
FRIDAY. ACCUMULATIONS IN THE MOUNTAINS LOOK TO BE UNDER ADVISORY
AMOUNTS. FOR TEMPERATURES...THURSDAY`S HIGHS SHOULD BE 4-8 C
COLDER THAN TODAY`S HIGHS. FRIDAY`S HIGHS ARE 0-3 C WARMER THAN
THURSDAY`S. FOR THE LATER DAY`S...SATURDAY THROUGH TUESDAY...
MODELS HAVE DECREASING NORTHWESTERLY FLOW ALOFT ON SATURDAY AS AN
UPPER RIDGE MOVES IN AND ACROSS THE CWA BY SUNDAY. THE NEXT UPPER
TROUGH GETS INTO WESTERN COLORADO BY 12Z MONDAY AND ACROSS THE CWA
BY EARLY MONDAY EVENING. DECREASING NORTHWESTERLY FLOW ALOFT
MONDAY NIGHT GIVES WAY TO ANOTHER UPPER RIDGE ON TUESDAY. THE LATE
SUNDAY NIGHT THROUGH LATE MONDAY TROUGH LOOKS TO HAVE OK MOISTURE
..FAIR COLD AIR...AND UPSLOPE FOR THE PLAINS AND FOOTHILLS.
WE`LL SEE.
AVIATION...EARLY THIS MORNING WINDS WERE DRAINAGE WITH A BKN DECK
AROUND 9000 FT. SATELLITE ALREADY SHOWS THIS BKN DECK MOVING SE SO
SKIES SHOULD ONLY SEE SOME HIGHER CLOUDS. BY LATE THIS MORNING
INTO THE EARLY AFTN THE GUSTY WNW WINDS NR THE FOOTHILLS LOOK LIKE
THEY WILL GRADUALLY SPREAD ACROSS THE AIRPORT WITH SOME GUSTS TO
20-25 POSSIBLE FM 19Z-23Z BEFORE DECREASING. BY EARLY THIS EVENING
WILL KEEP THEM MORE WSW AND THEN SSW BY 06Z. WILL SEE SOME HIGHER
LEVEL CLOUD COVER THIS AFTN AND TONIGHT BUT NOTHING BLO 20000 FT.
A CDFNT WILL MOVE INTO THE AREA BY 15Z ON THU WITH WINDS BECOMING
NNE ALONG WITH LOWER CEILINGS DEVELOPING.
&&
.BOU WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...D-L
LONG TERM....RJK
AVIATION...D-L
AREA FORECAST DISCUSSION
NWS COLUMBIA SC
226 PM EST WED FEB 13 2013
.SYNOPSIS...
LOW PRESSURE WILL BE LIFTING NORTHEAST OF THE FORECAST AREA THROUGH
TONIGHT. THE PRESSURE GRADIENT WILL RELAX AND WINDS WILL DIMINISH
TONIGHT AS THE LOW MOVES FARTHER AWAY. WEAK HIGH PRESSURE WILL
DOMINATE THURSDAY AND FRIDAY.
&&
.NEAR TERM /THROUGH TONIGHT/...
THIS AFTERNOON...LOW PRESSURE IS LIFTING NORTHEAST OF THE AREA.
THE PRESSURE GRADIENT ASSOCIATED WITH THIS LOW WILL BRING BREEZY
CONDITIONS. THE NAM BUFKIT MOMENTUM TRANSFER INDICATED GUSTS OF 25
TO 30 KNOTS. THE HRRR INDICATED GUSTS OF 30 TO 35 KNOTS OVER MUCH
OF THE AREA THIS AFTERNOON. OBSERVATION TRENDS SUPPORT THESE WIND
GUSTS. A LAKE WIND ADVISORY REMAINS IN EFFECT. AN AREA OF
CONVERGENCE WAS SUPPORTING A BROKEN LINE OF SHOWERS IN THE
FORECAST AREA. THIS LINE SHOULD MOVE OUT OF THE AREA LATER THIS
AFTERNOON AND EXPECT COVERAGE WILL REMAIN LIMITED BY ISENTROPIC
DOWNGLIDE.
TONIGHT...THE LOW WILL BE SHIFTING FARTHER NORTHEAST OF THE AREA
WITH A DIMINISHING PRESSURE GRADIENT AND WIND. MODEL TIME
SECTIONS SHOW FURTHER LOW-LEVEL DRYING. HIGH CLOUDINESS
ASSOCIATED WITH AN UPPER-LEVEL SPEED MAXIMUM WILL SHIFT EASTWARD
TONIGHT. WE USED THE GUIDANCE CONSENSUS FOR THE TEMPERATURE
FORECAST.
&&
.SHORT TERM /THURSDAY THROUGH FRIDAY NIGHT/...
THE NAM AND GFS SHOW WEAK RIDGING DOMINATING THURSDAY INTO FRIDAY. A
REINFORCING DRY COLD FRONT APPEARS TO CROSS THE AREA FRIDAY
AFTERNOON AND EVENING. THE GUIDANCE TEMPERATURES WERE CLOSE.
&&
.LONG TERM /SATURDAY THROUGH TUESDAY/...
THE GFS AND ECMWF SHOW DEEP AND PROGRESSIVE TROUGHING SATURDAY AND
SUNDAY. THERE HAVE BEEN MODEL DIFFERENCES WITH THE AMOUNT OF
MOISTURE ASSOCIATED WITH A SHORTWAVE TROUGH LATE SATURDAY...BUT
GENERALLY THE MESSAGE HAS BEEN LIMITED MOISTURE AND DOWNSLOPE
FLOW. THE MOS POPS FROM THE GFS AND ECMWF FOR THIS PERIOD OVER THE
PAST FEW DAYS HAVE BEEN LOW. WE HAVE MAINTAINED THE DRY FORECAST.
THE MODELS AGREE SHOWING HIGH MOISTURE TUESDAY ASSOCIATED WITH A
COLD FRONT. THE GFS AND ECMWF MOS SUPPORT BELOW NORMAL
TEMPERATURES SATURDAY THROUGH MONDAY...AND NEAR NORMAL DURING THE
REST OF THE MEDIUM-RANGE PERIOD.
&&
.AVIATION /19Z WEDNESDAY THROUGH MONDAY/...
A WEAK LOW PRESSURE SYSTEM WILL SLOWLY LIFT NORTH OF THE AREA THIS
AFTERNOON. A COLD FRONT WILL MOVE THROUGH BY EARLY THIS EVENING.
AS THE WARM FRONT LIFTS NORTH OF THE AREA CONDITIONS WILL IMPROVE
AND AS LOW CLOUDS BEGIN TO LIFT DURING THE 19Z-21Z TIME PERIOD. A
FEW SPRINKLES MAY STILL BE POSSIBLE AT THIS TIME. DEEP MIXING WITHIN
AN INCREASING PRESSURE GRADIENT/COLD FRONTAL PASSAGE FROM THE
WEST...WILL RESULT IN STRONG SOUTHWEST TO WESTERLY WINDS WITH GUSTS
TO 25 KNOTS. WINDS WILL SUBSIDE BY EARLY THIS EVENING...WITH SKIES
BECOMING CLEAR DURING THE OVERNIGHT HOURS. HIGH PRESSURE WILL BUILD
OVER THE AREA THURSDAY.
EXTENDED AVIATION OUTLOOK...NO SIGNIFICANT IMPACTS TO AVIATION
EXPECTED.
&&
.CAE WATCHES/WARNINGS/ADVISORIES...
SC...LAKE WIND ADVISORY UNTIL 8 PM EST THIS EVENING FOR SCZ015-016-
018-020>022-025>031-035>038-041.
GA...LAKE WIND ADVISORY UNTIL 8 PM EST THIS EVENING FOR GAZ040-
063>065-077.
&&
$$
AREA FORECAST DISCUSSION
NWS COLUMBIA SC
1235 PM EST WED FEB 13 2013
.SYNOPSIS...
LOW PRESSURE WILL BE LIFTING NORTHEAST OF THE FORECAST AREA THIS
AFTERNOON AND TONIGHT. WEAK HIGH PRESSURE WILL DOMINATE THURSDAY AND
FRIDAY.
&&
.NEAR TERM /THROUGH TONIGHT/...
LOW PRESSURE CENTERED NEAR THE FORECAST AREA WAS SUPPORTING AREAS
OF LIGHT RAIN AND DRIZZLE. LATER TODAY...THE LOW WILL BE FARTHER
NORTH OF THE AREA AND ISENTROPIC DOWNGLIDE WILL BECOME DOMINATE.
THE RAIN CHANCE SHOULD DECREASE. THE NAM AND GFS INDICATED H85
WINDS OF 40 TO 50 KNOTS AND THE KCAE 88D HAS VERIFIED THESE WINDS.
THE MODELS SHOWED THIS WIND CONTINUING FOR MUCH OF THE DAY...THEN
DIMINISHING LATE TODAY AND TONIGHT. LINGERING CLOUDINESS SHOULD
LIMIT MIXING...BUT WITH THE DRYING IN THE AFTERNOON IT SHOULD
BECOME BREEZY. THE NAM MOMENTUM TRANSFER INDICATED A POTENTIAL FOR
GUSTS NEAR 30 KNOTS. THE HRRR INDICATED WIND GUSTS OF 25 TO 30
KNOTS DEVELOPING IN THE SOUTH PART AROUND 100 PM...WITH GUSTS OF
30 TO 35 KNOTS OVER MUCH OF THE REMAINING AREA BEGINNING AROUND
300 PM. WE HAVE POSTED A LAKE WIND ADVISORY. MODEL TIME SECTIONS
SHOW FURTHER DRYING OVERNIGHT AND EXPECT SKIES WILL BECOME CLEAR.
WE USED THE GUIDANCE CONSENSUS FOR THE TEMPERATURE FORECAST.
&&
.SHORT TERM /THURSDAY THROUGH FRIDAY NIGHT/...
THE NAM AND GFS SHOW WEAK RIDGING DOMINATING THURSDAY INTO FRIDAY. A
REINFORCING DRY COLD FRONT APPEARS TO CROSS THE AREA FRIDAY
AFTERNOON AND EVENING. GUIDANCE AND LOCAL NUMBERS ARE VERY CLOSE
THROUGH THE PERIOD.
&&
.LONG TERM /SATURDAY THROUGH TUESDAY/...
ALL OF THE MODELS SHOW A DEEP...PROGRESSIVE...TROUGH ACROSS THE
EASTERN HALF OF THE COUNTRY SATURDAY. THE ECMWF AND GFS DIFFER ON
THE SPEED AND STRENGTH OF ADDITIONAL UPPER-LEVEL ENERGY MOVING
THROUGH THE TROUGH AND EVENTUALLY HELPING TO LIFT THE TROUGH TO
THE EAST AND NORTHEAST BY SUNDAY OR MONDAY. THE GFS DEVELOPS LOW
PRESSURE OFF THE MID ATLANTIC COAST SATURDAY AND IS FASTER. THE
SLOWER ECMWF...DEVELOPS LOW PRESSURE OFF THE CAROLINA COAST
SATURDAY NIGHT AND SUNDAY MORNING. AT THIS TIME...WILL KEEP THE
FORECAST DRY FOR THE WEEKEND. THIS WILL BE FOLLOWED BY ANOTHER
QUICK MOVING SYSTEM APPROACHING THE REGION TUESDAY. THE MODELS
AGREE SHOWING A MOISTURE INCREASE TUESDAY ASSOCIATED WITH A COLD
FRONT. THE GFS AND ECMWF MOS SUPPORT BELOW NORMAL TEMPERATURES
SATURDAY THROUGH MONDAY...AND NEAR NORMAL DURING THE REST OF THE
MEDIUM-RANGE PERIOD.
&&
.AVIATION /18Z WEDNESDAY THROUGH MONDAY/...
A WEAK BUT COMPLEX LOW PRESSURE SYSTEM WILL SLOWLY LIFT NORTHWARD
ACROSS THE AREA EARLY THIS AFTERNOON. EXPECT IFR OR LIFR CEILINGS TO
LIFT EARLY THIS AFTERNOON WITH PATCHY LIGHT SHOWERS OR DRIZZLE AT
TIMES...MAINLY OVER THE SC MIDLANDS.
AS THE WARM FRONT LIFTS NORTH OF THE AREA CONDITIONS SHOULD
IMPROVE AND AS LOW CLOUDS LIFT AFTER 18Z-21Z. DEEP MIXING WITHIN AN
INCREASING PRESSURE GRADIENT/COLD FRONTAL PASSAGE FROM THE
WEST...WILL RESULT IN STRONG SOUTHWEST TO WESTERLY WINDS WITH GUSTS
TO 25 KNOTS. WINDS WILL SUBSIDE BY EARLY THIS EVENING...WITH SKIES
BECOMING CLEAR DURING THE OVERNIGHT HOURS. HIGH PRESSURE WILL BUILD
OVER THE AREA THURSDAY.
EXTENDED AVIATION OUTLOOK...NO SIGNIFICANT IMPACTS TO AVIATION
EXPECTED.
&&
.CAE WATCHES/WARNINGS/ADVISORIES...
SC...LAKE WIND ADVISORY UNTIL 8 PM EST THIS EVENING FOR SCZ015-016-
018-020>022-025>031-035>038-041.
GA...LAKE WIND ADVISORY UNTIL 8 PM EST THIS EVENING FOR GAZ040-
063>065-077.
&&
$$
AREA FORECAST DISCUSSION
NWS LOUISVILLE KY
150 PM EST WED FEB 13 2013
.Forecast Update...
Issued at 150 PM EST Wed Feb 13 2013
Snow continues to wind down across northwest sections of the
forecast area. Satellite data does show clouds breaking up to our
west so some peeks of sunshine will be possible. Temperatures have
already risen a few degrees since the snowfall ended and snow has
largely melted away already in the Metro area. With the threat of
snow greatly diminished, have gone ahead and cancelled the western
section of the winter weather advisory.
Further east, band of light to moderate snow continues to work
eastward and will be impacting the Lexington metro region. This
will put down a quick accumulation mainly on grassy surfaces before
diminishing to flurries later this afternoon.
&&
.Short Term (Now through Thursday)...
Issued at 325 AM EST Wed Feb 13 2013
...Light Slushy Snow Accumulations Possible Today...
As of 745Z, an upper trough was over MO with sfc low pressure over
the Gulf States. Precipitation associated with this system
stretched from western KY to eastern OK as of 745Z with rain
observed over most areas ESE of the upper trough and snow or a
rain/snow mix observed over portions of OK/MO/AR in the upper level
trough. The 6Z NAM12 and last few RAP runs seem to have the best
handle on the area of precipitation and general schematic of ptype.
Overall timing of the best precip and forcing seems to be a little
earlier than previously thought. Looks like the best dynamics and
precip should fall over our region between 12-18Z. Also, the latest
runs of the NAM and RAP have moved the best band of moderate to
heavy precip...probably a heavy wet snow as observed out in MO...to
the north. According to these models, the best snow band in which
we could see 1-2 inches of wet, slushy snow would be in a corridor
along the Ohio River to along the Western KY and Bluegrass
Parkways. Other areas over southern Indiana and south central KY
may see a brief mix of rain/snow...enough to create a dusting to a
half inch before quickly melting off. There is still some
uncertainty in where the band of moderate to heavy snow will set up
so stay tuned to morning forecast updates. Also, because of the
uncertainty, will continue with the SPS product instead of going
with an advisory although one may be needed later this morning.
So for today expect light rain to overspread the area before sunrise
with possibly some snow grains mixing in over southern Indiana and
northern KY at precip onset due to a deeper cold layer. After
sunrise we`ll start to see colder air filter in with the upper
trough causing precip to change over to a rain/snow mix and then
probably all snow for a time over southern Indiana and central KY.
The morning hours after sunrise through early afternoon will be the
best time for a period of moderate to heavy wet snow resulting in
slushy snow accumulations as high as 1-2 inches over north central
KY. This period of wintry precip may cause some travel issues.
We`ll continue to see a early afternoon before precip exits to our
east by late afternoon/early evening. Once snow comes to an end
over any location, quick melting can be expected as sfc temps are
expected to be above freezing today. In fact, most locations will
still top out in the upper 30s to lower 40s this afternoon despite
any morning/early afternoon snow.
For tonight and Thurs, expect dry conditions with partly cloudy
skies. Low temps will be in the upper 20s to lower 30s tonight. An
upper level trough and cold front will approach the region by Thurs
evening. Ahead of the trough, though, Thurs will be quite warm with
a strong southerly flow in place. High temps Thurs should be in the
low to mid 50s.
.Long Term (Thursday Night - Tuesday)...
Issued at 320 AM EST Wed Feb 13 2013
...A few shots for snow showers followed by a warm up and another
strong storm system early next week...
A lead shortwave will move across the Great Lakes on Thursday night,
with the associated surface system dragging a moisture starved cold
frontal boundary through the region. A secondary shortwave will
quickly move across the Ohio Valley on Friday as overall trough
envelopes the eastern CONUS. Friday looks to be the best setup for
some snow showers across the area as enough deep moisture combines
with steep low and mid level lapse rates, and an upslope surface
component. Soundings for this time period do show some convective
instability with saturation well into the -10 -20 C range across
northern portions of the CWA. Surface temperatures may squeak into
the mid and upper 30s on Friday, however thermal profile will be
easily cold enough for all snow showers below 40 degrees, some of
which could produce bursts of heavy snow and gusty winds.
At this point, best location for snow looks to be across southern
Indiana and north central Kentucky. As was mentioned in the previous
forecast, these snow showers have the potential to cause an impact
across the region with very light but quick accumulations. This setup
will have to be monitored.
We should see a lull in the activity on Friday night with subsidence
behind the quickly departing shortwave. Temperatures will be much
cooler with lows dropping into the mid 20s. By Saturday, confidence
is low as to exact placement of trough axis. Models are still having
trouble with the timing/placement of individual waves and the
overall progression of the east CONUS trough amplification. Have
continued the trend of a drier Saturday as a GFS/GEM/GFS ensemble
mean consensus agree on an eastern solution with subsidence aloft
already in place across the Ohio Valley on Saturday. The less
consistent ECMWF still holds the axis to the west. Will only mention
a slight chance of a snow shower east of I-65 to account for this.
May be able to go completely dry for Saturday with the next set of
model runs. Temperatures will be cooler than Friday with highs only
topping out in the low and mid 30s.
Saturday night/Sunday morning will be the coldest of the period as
lows drop to around 20. Radiational cooling conditions will not be
optimal as surface winds stay up a bit and some upper level clouds
look to stream overhead. Therefore, cannot drop low too near dew
points that will be in the lower teens. May be able to decouple a
few of the coolest spots into the upper teens but the upper level
cloud cover should mostly mitigate this.
Saturday night through most of Monday should be dry as surface high
pressure holds over the area and weak upper level ridging holds.
Sunday will begin the warming trend with highs warming into the mid
30s to low 40s. Highs on Monday will be much milder with a return of
southerly flow. The mercury should rebound to the low 50s in most
spots.
By Monday afternoon we will begin to focus on the next storm system
that looks to impact the area through Tuesday. This system will
develop as a lee surface low intensifies ahead of a digging trough
over the central Plains. At this point the low looks to move from
the southern Plains, northeastward either into the Ohio Valley or
just north to the lower Great Lakes through Tuesday morning. This
warmer solution would bring overrunning rain showers to the area
late Monday afternoon, with more widespread rain moving into the
area Monday night and early Tuesday. Temperatures will likely crash
quickly behind the system on Tuesday afternoon as sharp trough moves
through and may eventually have to mention rain changing to snow.
Will stick with all rain for now as it is too early to mention these
details, especially with the low track in question. Will also leave
any thunder mention out of the forecast with the bulk of the
precipitation as any moisture return/instability would be limited by
short duration of southerly flow. This system will have to be
watched however, as a more northerly solution or deeper sfc low
would change the instability picture. Also, chose to disregard the
more southern solution offered by the operational ECMWF. This seems
to be the outlier, with a general consensus between the GFS/GEM/GFS
ensemble mean/ECMWF ensemble mean of a northern solution.
&&
.Aviation (18Z TAF Issuance)...
Issued at 1235 PM EST Wed Feb 13 2013
Mid-level vorticity maximum continues to push eastward across the
forecast area this afternoon. Weakening band of heavy to moderate
snow will continue to push eastward. It should be east of KSDF by
the beginning of the TAF period, but several bands still remain to
the west which should push through over the next hour. MVFR
conditions look likely, but can not rule out a tempo drop to IFR as
these bands push through. VFR conditions are expected to return to
KSDF by 13/21Z and continue through the remainder of the TAF
period. Winds will be out of the northwest at 5-8 knots and then
gradually shift the west and then southwest later this afternoon and
tonight.
Over at KLEX, band of snow between KSDF and KLEX will push eastward
this afternoon and bring snow to the KLEX terminal. Current
thinking is the band will go through KLEX between 13/18-20Z or so
and conditions will likely drop to IFR for a short period of time
before rising back up to MVFR by 13/21Z. VFR conditions should
return to KLEX by 14/00Z. Surface winds will be out of northwest at
8-10 kts with winds shifting back to the west/southwest tonight.
Down at KBWG, some light rainfall mixed with a little snow will be
possible over the next few hours. In general, MVFR cigs and VFR
visibilities are expected, but VFR conditions should return by
13/21Z. VFR conditions are expected overnight with winds remaining
out of the southwest at 3-6 knots.
&&
.LMK WATCHES/WARNINGS/ADVISORIES...
IN...NONE.
KY...WINTER WEATHER ADVISORY UNTIL 7 PM EST THIS EVENING FOR
KYZ035>037-039>043-046>049-054>057-067.
$$
Update...........MJ
Short Term.......AMS
Long Term........BJS
Aviation.........MJ
AREA FORECAST DISCUSSION
NWS JACKSON KY
113 PM EST WED FEB 13 2013
.UPDATE...
ISSUED AT 931 AM EST WED FEB 13 2013
LIGHT...INTERMITTENT RAIN WITH TEMPS AROUND 40 COVERING MOST OF THE
CWFA. LOWER TEMPS AND LIGHT SNOW TO OUR WEST. UPDATED GRIDS TO
INDICATE LATE MORNING HIGH TEMPS AND THEN FALLING TEMPS THIS
AFTERNOON. RAIN SHOULD CHANGE TO SNOW AND THERE MAY BE A FEW BANDS OF
SNOW TO ACCUMULATE BUT THE GROUND AND ESPECIALLY THE ROADS ARE TOO
WARM TO SUPPORT OTHER THAN MOMENTARY ACCUMULATIONS. BY THE TIME THE
COLD AIR ARRIVES AND THE RAIN CHANGES TO ALL SNOW...MOST OF THE
MOISTURE WILL BE EAST OF THE AREA AND JUST A FEW FLURRIES WILL REMAIN
FOR ALL BUT THE HIGHER ELEVATIONS NEAR THE VA/W VA BORDER. UPDATED
GRIDS AND ZONES WITH LATEST INFORMATION.
UPDATE ISSUED AT 658 AM EST WED FEB 13 2013
CURRENT CONDITIONS ACROSS EASTERN KENTUCKY HAVE PRECIP MOVING INTO
THE AREA WITH RAIN REACHING THE GROUND IN THE SOUTH. HAVE UPDATED TO
FINE TUNE POPS AND ANY COOLING EFFECTS TO TEMPS FROM THE RAINFALL.
UPSTREAM...IT SEEMS THE BAND SETTING UP WILL STAY JUST NORTH SO WILL
KEEP CURRENT SNOWFALL FORECAST IN PLACE. ONLY CONCERN RIGHT NOW IS
THE COOLING EFFECTS AND SURFACE TEMPS OVER THE SOUTH AS SOME REPORTS
OF MODERATE RAIN POSSIBLY REALLY COOLING SURFACE TEMPS. WILL BANK ON
SURFACE TEMPS STAYING WARM ENOUGH THROUGH THE EARLY AFTERNOON BEFORE
THE COLD AIR FINALLY CHANGES THE RAIN OVER THIS AFTERNOON.
ALSO...MODEL SOUNDINGS CONTINUE TO SHOW DRY AIR AIR AT THE 10 DEGREE
CELSIUS TEMPS AND HIGHER SO WILL KEEP THE INCH OR SNOW FORECAST NORTH
OF THE MOUNTAIN PARKWAY AND IN THE HIGHEST ELEVATIONS SO NO NEW ZFP
WAS NEEDED.
&&
.SHORT TERM...(TODAY THROUGH THURSDAY)
ISSUED AT 423 AM EST WED FEB 13 2013
CURRENT 09Z ANALYSIS ACROSS THE AREA HAS WIDESPREAD CLOUD COVER OVER
EASTERN KENTUCKY WITH PRECIP ALONG THE TN AND KY BORDER IN SOUTH
CENTRAL KY DEVELOPING AND MOVING INTO THE AREA. CURRENT TEMPERATURES
ACROSS THE SOUTHERN PORTION OF THE AREA ARE IN THE LOW 40S TO UPPER
30S. HOWEVER SURFACE TEMPS ALONG AND NORTH OF THE MOUNTAIN PARKWAY
ARE COLD ENOUGH TO SUSTAIN SOME SNOWFALL AS THE PRECIP WILL CREEP
INTO THE NORTHERN PORTION OF THE CWA BY 12Z. MET SAT DATA CURRENTLY
SHOWS THE DEVELOPING SURFACE LOW OVER THE LOWER TN VALLEY AND
SHIFTING OFF TO THE NORTHEAST. THE UPPER LOW IS LOCATED OVER SOUTHERN
IL MOVING TO THE EAST NORTHEAST. CURRENT SHORT TERM MODELS INDICATE A
BAND OF HEAVY PRECIP SETTING UP. THE CHALLENGE HERE IS THE LOCATION
OF THE DEVELOPMENT. BOTH THE NAM AND GFS HAVE INDICATED A BAND OF
HEAVIER PRECIP JUST SOUTH OF THE OH RIVER AND ALSO ANOTHER BAND
GOING THROUGH CENTRAL EASTERN KY. THE HI RES HRRR ALSO SHOWS THIS BUT
WITH THE SOUTHERN BAND NOT AS INTENSE. BASED ON CURRENT WV SHOWING
MID LEVEL MOISTURE AND ADVECTING TOWARD THE UPPER OH VALLEY...HAVE
GONE WITH THE BLUEGRASS AND LOCATIONS NORTH OF THE MOUNTAIN PARKWAY TO
RECEIVE UP TO AN INCH OF SNOWFALL. CURRENT THOUGH IS WITH THE
SOUTHEAST KY STILL QUITE WARMER THAN THE NORTH LOCATIONS...THE BAND
INDICATED THROUGH THE CENTRAL PORTION OF EAST KY...WILL MAINLY BE A
RAIN PRODUCER WITH THE BEST CHANCE FOR ACCUMULATING SNOW ION THE
HIGHER TERRAIN ALONG THE VA BORDER. AS WELL...NAM MODEL SOUNDINGS
STILL SHOW A POOR DENDRITE GROWTH ZONE THROUGH MUCH OF THE
EVENT...LOCATED FROM THE JKL POINT AND SOUTH.
BASED ON ALL THESE FACTORS...HAVE KEPT THE SPS GOING WITH THE INCH
POSSIBLE NORTH OF THE MOUNTAIN PARKWAY AND IN THE HIGHER TERRAIN
ALONG THE VA BORDER. IF THE BAND IN THE NORTH DOES SLIDE SOUTH A
BIT...THE BLUE GRASS COUNTIES WILL QUICKLY REACH ADVISORY CRITERIA.
FOR THE REST OF THE SHORT TERM...A PROGRESSIVE PATTERN REMAINS...SUCH
THAT...LOCATIONS THAT FINALLY BECOME COLD ENOUGH TO SUPPORT SNOW THIS
EVENING AND TONIGHT...MUCH OF THE MOISTURE WILL BE OUT OF THE AREA
WITH A FEW FLURRIES POSSIBLE. THE PATTERN WILL ALLOW A BRIEF STAY FOR
THIS COLDER AIR MASS AS THURSDAY HIGH TEMPS WILL QUICKLY WARM INTO
THE UPPER 40S...MELTING ANY SNOW THAT FALLS TODAY AND TONIGHT.
.LONG TERM...(THURSDAY NIGHT THROUGH TUESDAY)
ISSUED AT 341 AM EST WED FEB 13 2013
THE MODEL START OFF IN FAIRLY GOOD AGREEMENT WITH AN UPPER TROUGH
EXTENDING ACROSS THE MIDWEST. THIS UPPER TROUGH WILL PUSH A WEAK
FRONT ACROSS THE AREA ON FRIDAY BRINGING INITIALLY A MIX OF RAIN AND
SNOW IN THE MORNING AND THEN TURNING TO ALL RAIN AS IT WARMS UP A
LITTLE IN THE AFTERNOON AND THEN A MIX OF RAIN AND SNOW AGAIN IN THE
EVENING WHEN THINGS COOL OFF AGAIN. AT WORST...A DUSTING OF SNOW IS
EXPECTED WITH THIS SYSTEM. SOME FLURRIES OR VERY LIGHT SNOW IS
POSSIBLE ON SATURDAY AS THE UPPER TROUGH MOVES THROUGH THE AREA.
THIS IS ALSO WHERE THE MODELS REALLY BEGIN TO DIVERGE WITH THE ECMWF
ABOUT 12 HOURS SLOWER WITH THE UPPER TROUGH PASSAGE. ALSO THE ECMWF
HAS A MUCH SHARPER AND DEEPER UPPER TROUGH THAN THE GFS. THE MODELS
THEN GET INTO BETTER AGREEMENT WITH A MORE ZONAL PATTERN DEVELOPING
ACROSS THE US. THE NEXT SYSTEM TO MOVE ACROSS EASTERN KENTUCKY WILL
BE ON TUESDAY. HERE THE ECMWF IS THE FASTER OF THE TWO SYSTEMS.
DECIDED TO GO WITH THE FASTER ECMWF FOR THE TUESDAY SYSTEM. THE
PATTERN THUS REMAINS ACTIVE...HOWEVER NO MAJOR SYSTEMS WITH BIG
IMPACT ARE EXPECTED. FOR THE TEMPERATES...GENERALLY NUDGED THE MODEL
BLEND TOWARD THE NEW AND GENERALLY WARMER ECMWF RAW DATA FOR THE
TEMPERATURE FORECAST.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z THURSDAY AFTERNOON)
ISSUED AT 108 PM EST WED FEB 13 2013
CEILINGS HAVE DROPPED TO IFR LEVELS. PRECIP HAS FALLEN THROUGH THE
MORNING ACROSS THE AREA IN THE FORM OF -RA. EXPECT THIS TO MIX WITH
AND THEN CHANGE TO -SN LATER THIS AFTERNOON. ACCUMULATIONS WILL BE
GENERALLY LIGHT EXCEPT IN NORTHERN KY WHERE A QUICK INCH COULD FALL.
PRECIP SHOULD END ACROSS EASTERN KENTUCKY BETWEEN 1-3Z WITH
CIGS/VSBY LIFTING TO VFR. WHERE THERE IS PRECIPITATION...THE -RA AND
THEN THE MIX OF TYPES COULD CAUSE SOME ICE ACCUMULATION WHEN AIRBORNE.
&&
.JKL WATCHES/WARNINGS/ADVISORIES...
WINTER WEATHER ADVISORY UNTIL 7 PM EST THIS EVENING FOR KYZ044-
050>052.
&&
$$
UPDATE...DUSTY
SHORT TERM...SHALLENBERGER
LONG TERM...JJ
AVIATION...DUSTY
AREA FORECAST DISCUSSION
NWS LOUISVILLE KY
1203 PM EST WED FEB 13 2013
.Forecast Update...
Issued at 1202 PM EST Wed Feb 13 2013
Heavy snow band continues to steadily move eastward. The band is
now located just east and southeast of the Ohio River and currently
pushing through Louisville metro. This band has shown some
weakening in the last hour or so, but with the band passing over the
radar site, we might be seeing a little attenuation in the current
radar moments. This band will continue to head east through the
afternoon hours. Thus, have gone ahead and expanded the advisory to
the east to include all of the Bluegrass region of central
Kentucky. Overall, not expecting that many problems with
accumulation on the road surfaces as they have been pretty warm.
However, a short period of slushy roads will be
possible...especially on bridges and overpasses.
Further south, there is a little bit more warm air moving in which
is keeping the precipitation more in a mixed mode. It appears,
based on observations and reports that the pure snow line is along
the southern edge of the advisory area. Some colder air will move
in this afternoon which may result in a little more snow, but
accumulations will be very limited with a dusting or less.
There are some secondary bands that have formed to the west and
northwest across southern Indiana. In general, this snow is much
lighter than the main band, but light snow looks to continue through
the afternoon in southern Indiana with little additional
accumulation, and that would be limited to grassy surfaces.
&&
.Short Term (Now through Thursday)...
Issued at 325 AM EST Wed Feb 13 2013
...Light Slushy Snow Accumulations Possible Today...
As of 745Z, an upper trough was over MO with sfc low pressure over
the Gulf States. Precipitation associated with this system
stretched from western KY to eastern OK as of 745Z with rain
observed over most areas ESE of the upper trough and snow or a
rain/snow mix observed over portions of OK/MO/AR in the upper level
trough. The 6Z NAM12 and last few RAP runs seem to have the best
handle on the area of precipitation and general schematic of ptype.
Overall timing of the best precip and forcing seems to be a little
earlier than previously thought. Looks like the best dynamics and
precip should fall over our region between 12-18Z. Also, the latest
runs of the NAM and RAP have moved the best band of moderate to
heavy precip...probably a heavy wet snow as observed out in MO...to
the north. According to these models, the best snow band in which
we could see 1-2 inches of wet, slushy snow would be in a corridor
along the Ohio River to along the Western KY and Bluegrass
Parkways. Other areas over southern Indiana and south central KY
may see a brief mix of rain/snow...enough to create a dusting to a
half inch before quickly melting off. There is still some
uncertainty in where the band of moderate to heavy snow will set up
so stay tuned to morning forecast updates. Also, because of the
uncertainty, will continue with the SPS product instead of going
with an advisory although one may be needed later this morning.
So for today expect light rain to overspread the area before sunrise
with possibly some snow grains mixing in over southern Indiana and
northern KY at precip onset due to a deeper cold layer. After
sunrise we`ll start to see colder air filter in with the upper
trough causing precip to change over to a rain/snow mix and then
probably all snow for a time over southern Indiana and central KY.
The morning hours after sunrise through early afternoon will be the
best time for a period of moderate to heavy wet snow resulting in
slushy snow accumulations as high as 1-2 inches over north central
KY. This period of wintry precip may cause some travel issues.
We`ll continue to see a early afternoon before precip exits to our
east by late afternoon/early evening. Once snow comes to an end
over any location, quick melting can be expected as sfc temps are
expected to be above freezing today. In fact, most locations will
still top out in the upper 30s to lower 40s this afternoon despite
any morning/early afternoon snow.
For tonight and Thurs, expect dry conditions with partly cloudy
skies. Low temps will be in the upper 20s to lower 30s tonight. An
upper level trough and cold front will approach the region by Thurs
evening. Ahead of the trough, though, Thurs will be quite warm with
a strong southerly flow in place. High temps Thurs should be in the
low to mid 50s.
.Long Term (Thursday Night - Tuesday)...
Issued at 320 AM EST Wed Feb 13 2013
...A few shots for snow showers followed by a warm up and another
strong storm system early next week...
A lead shortwave will move across the Great Lakes on Thursday night,
with the associated surface system dragging a moisture starved cold
frontal boundary through the region. A secondary shortwave will
quickly move across the Ohio Valley on Friday as overall trough
envelopes the eastern CONUS. Friday looks to be the best setup for
some snow showers across the area as enough deep moisture combines
with steep low and mid level lapse rates, and an upslope surface
component. Soundings for this time period do show some convective
instability with saturation well into the -10 -20 C range across
northern portions of the CWA. Surface temperatures may squeak into
the mid and upper 30s on Friday, however thermal profile will be
easily cold enough for all snow showers below 40 degrees, some of
which could produce bursts of heavy snow and gusty winds.
At this point, best location for snow looks to be across southern
Indiana and north central Kentucky. As was mentioned in the previous
forecast, these snow showers have the potential to cause an impact
across the region with very light but quick accumulations. This setup
will have to be monitored.
We should see a lull in the activity on Friday night with subsidence
behind the quickly departing shortwave. Temperatures will be much
cooler with lows dropping into the mid 20s. By Saturday, confidence
is low as to exact placement of trough axis. Models are still having
trouble with the timing/placement of individual waves and the
overall progression of the east CONUS trough amplification. Have
continued the trend of a drier Saturday as a GFS/GEM/GFS ensemble
mean consensus agree on an eastern solution with subsidence aloft
already in place across the Ohio Valley on Saturday. The less
consistent ECMWF still holds the axis to the west. Will only mention
a slight chance of a snow shower east of I-65 to account for this.
May be able to go completely dry for Saturday with the next set of
model runs. Temperatures will be cooler than Friday with highs only
topping out in the low and mid 30s.
Saturday night/Sunday morning will be the coldest of the period as
lows drop to around 20. Radiational cooling conditions will not be
optimal as surface winds stay up a bit and some upper level clouds
look to stream overhead. Therefore, cannot drop low too near dew
points that will be in the lower teens. May be able to decouple a
few of the coolest spots into the upper teens but the upper level
cloud cover should mostly mitigate this.
Saturday night through most of Monday should be dry as surface high
pressure holds over the area and weak upper level ridging holds.
Sunday will begin the warming trend with highs warming into the mid
30s to low 40s. Highs on Monday will be much milder with a return of
southerly flow. The mercury should rebound to the low 50s in most
spots.
By Monday afternoon we will begin to focus on the next storm system
that looks to impact the area through Tuesday. This system will
develop as a lee surface low intensifies ahead of a digging trough
over the central Plains. At this point the low looks to move from
the southern Plains, northeastward either into the Ohio Valley or
just north to the lower Great Lakes through Tuesday morning. This
warmer solution would bring overrunning rain showers to the area
late Monday afternoon, with more widespread rain moving into the
area Monday night and early Tuesday. Temperatures will likely crash
quickly behind the system on Tuesday afternoon as sharp trough moves
through and may eventually have to mention rain changing to snow.
Will stick with all rain for now as it is too early to mention these
details, especially with the low track in question. Will also leave
any thunder mention out of the forecast with the bulk of the
precipitation as any moisture return/instability would be limited by
short duration of southerly flow. This system will have to be
watched however, as a more northerly solution or deeper sfc low
would change the instability picture. Also, chose to disregard the
more southern solution offered by the operational ECMWF. This seems
to be the outlier, with a general consensus between the GFS/GEM/GFS
ensemble mean/ECMWF ensemble mean of a northern solution.
&&
.Aviation (12Z TAF Issuance)...
Issued at 605 AM EST Wed Feb 13 2013
An upper level trough will pass through the area today with a sfc
low pressure passing to our south. Precipitation associated with
this weather system has already begun to spread northward into
central KY this morning. At the beginning of TAF time, it should be
raining near all TAF sites with SDF/LEX rains being more
intermittent showers until deeper moisture overtakes the low level
dry layer. After sunrise, good forcing will enter the region
causing steady moderate banded precip over the region. It`s hard to
say whether a moderate band will affect the TAF sites, but at least
feel confident enough to include lower MVFR conditions this morning
through early afternoon as the heavier precip moves through the
region. Some IFR cigs may be possible in some of the heavier bands
of precip especially near BWG but will not include in the TAF at
this time as confidence is low. Rain is expected to be the
predominant precip type for BWG, however, SDF/LEX could see a RASN
mix in a moderate band. A RASN mix isn`t out of the realm of
possibilities for BWG either, but seems most likely at SDF/LEX at
this time. Will need to adjust as the precip bands set up this
morning and move closer to our area. By mid to late afternoon,
precip should move east of the TAF sites with conditions returning
to high end MVFR and then VFR by this evening.
Winds will be predominantly NNE as the weather system moves through
the area this morning through mid afternoon. Winds will strengthen
throughout the day likely exceeding 7kt at times. Winds will shift
to the WNW behind this system by this evening.
NAM model soundings indicate a layer of low level moisture for
tomorrow morning which could indicate a light fog or low cigs. Will
not place flight restrictions at the end of the TAFs for now, but it
will be something to investigate further.
&&
.LMK WATCHES/WARNINGS/ADVISORIES...
IN...WINTER WEATHER ADVISORY UNTIL 4 PM EST /3 PM CST/ THIS AFTERNOON
FOR INZ076>079-083-084-089>092.
KY...WINTER WEATHER ADVISORY UNTIL 4 PM EST /3 PM CST/ THIS AFTERNOON
FOR KYZ023>034-038-045-053.
WINTER WEATHER ADVISORY UNTIL 7 PM EST THIS EVENING FOR
KYZ035>037-039>043-046>049-054>057-067.
$$
Update...........MJ
Short Term.......AMS
Long Term........BJS
Aviation.........AMS
AREA FORECAST DISCUSSION
NWS LOUISVILLE KY
1103 AM EST WED FEB 13 2013
.Mesoscale Forecast Update...
Issued at 1103 AM EST Wed Feb 13 2013
Strong frontogenetical heavy snow band is now moving into the
Louisville Metro area. Conditions across the metro will deteriorate
quickly over the next 15-20 minutes as the snow picks up.
Visibilities will drop to less than a mile and the snow will quickly
accumulate. Temperatures have continued to drop to near their
dewpoints in the snow band, so we expect temperatures to drop right
to freezing in the next half hour as the band pushes in. The heavy
snow will last about 60-90 minutes and a good 1-2" of accumulation
is likely.
Webcams to our north and northwest show the accumulating snows
well. Via social media, we`re seeing reports of 2-3" and we had a
co-op observer in Crawford County IN report 2 inches in the last
hour. This snow band will also affect areas to the southwest of
Louisville including areas from Harrison County Indiana southwest
through Meade/Breckinridge/Hardin/Ohio/Grayson counties over the
next 60-90 minutes.
&&
.Short Term (Now through Thursday)...
Issued at 325 AM EST Wed Feb 13 2013
...Light Slushy Snow Accumulations Possible Today...
As of 745Z, an upper trough was over MO with sfc low pressure over
the Gulf States. Precipitation associated with this system
stretched from western KY to eastern OK as of 745Z with rain
observed over most areas ESE of the upper trough and snow or a
rain/snow mix observed over portions of OK/MO/AR in the upper level
trough. The 6Z NAM12 and last few RAP runs seem to have the best
handle on the area of precipitation and general schematic of ptype.
Overall timing of the best precip and forcing seems to be a little
earlier than previously thought. Looks like the best dynamics and
precip should fall over our region between 12-18Z. Also, the latest
runs of the NAM and RAP have moved the best band of moderate to
heavy precip...probably a heavy wet snow as observed out in MO...to
the north. According to these models, the best snow band in which
we could see 1-2 inches of wet, slushy snow would be in a corridor
along the Ohio River to along the Western KY and Bluegrass
Parkways. Other areas over southern Indiana and south central KY
may see a brief mix of rain/snow...enough to create a dusting to a
half inch before quickly melting off. There is still some
uncertainty in where the band of moderate to heavy snow will set up
so stay tuned to morning forecast updates. Also, because of the
uncertainty, will continue with the SPS product instead of going
with an advisory although one may be needed later this morning.
So for today expect light rain to overspread the area before sunrise
with possibly some snow grains mixing in over southern Indiana and
northern KY at precip onset due to a deeper cold layer. After
sunrise we`ll start to see colder air filter in with the upper
trough causing precip to change over to a rain/snow mix and then
probably all snow for a time over southern Indiana and central KY.
The morning hours after sunrise through early afternoon will be the
best time for a period of moderate to heavy wet snow resulting in
slushy snow accumulations as high as 1-2 inches over north central
KY. This period of wintry precip may cause some travel issues.
We`ll continue to see a early afternoon before precip exits to our
east by late afternoon/early evening. Once snow comes to an end
over any location, quick melting can be expected as sfc temps are
expected to be above freezing today. In fact, most locations will
still top out in the upper 30s to lower 40s this afternoon despite
any morning/early afternoon snow.
For tonight and Thurs, expect dry conditions with partly cloudy
skies. Low temps will be in the upper 20s to lower 30s tonight. An
upper level trough and cold front will approach the region by Thurs
evening. Ahead of the trough, though, Thurs will be quite warm with
a strong southerly flow in place. High temps Thurs should be in the
low to mid 50s.
.Long Term (Thursday Night - Tuesday)...
Issued at 320 AM EST Wed Feb 13 2013
...A few shots for snow showers followed by a warm up and another
strong storm system early next week...
A lead shortwave will move across the Great Lakes on Thursday night,
with the associated surface system dragging a moisture starved cold
frontal boundary through the region. A secondary shortwave will
quickly move across the Ohio Valley on Friday as overall trough
envelopes the eastern CONUS. Friday looks to be the best setup for
some snow showers across the area as enough deep moisture combines
with steep low and mid level lapse rates, and an upslope surface
component. Soundings for this time period do show some convective
instability with saturation well into the -10 -20 C range across
northern portions of the CWA. Surface temperatures may squeak into
the mid and upper 30s on Friday, however thermal profile will be
easily cold enough for all snow showers below 40 degrees, some of
which could produce bursts of heavy snow and gusty winds.
At this point, best location for snow looks to be across southern
Indiana and north central Kentucky. As was mentioned in the previous
forecast, these snow showers have the potential to cause an impact
across the region with very light but quick accumulations. This setup
will have to be monitored.
We should see a lull in the activity on Friday night with subsidence
behind the quickly departing shortwave. Temperatures will be much
cooler with lows dropping into the mid 20s. By Saturday, confidence
is low as to exact placement of trough axis. Models are still having
trouble with the timing/placement of individual waves and the
overall progression of the east CONUS trough amplification. Have
continued the trend of a drier Saturday as a GFS/GEM/GFS ensemble
mean consensus agree on an eastern solution with subsidence aloft
already in place across the Ohio Valley on Saturday. The less
consistent ECMWF still holds the axis to the west. Will only mention
a slight chance of a snow shower east of I-65 to account for this.
May be able to go completely dry for Saturday with the next set of
model runs. Temperatures will be cooler than Friday with highs only
topping out in the low and mid 30s.
Saturday night/Sunday morning will be the coldest of the period as
lows drop to around 20. Radiational cooling conditions will not be
optimal as surface winds stay up a bit and some upper level clouds
look to stream overhead. Therefore, cannot drop low too near dew
points that will be in the lower teens. May be able to decouple a
few of the coolest spots into the upper teens but the upper level
cloud cover should mostly mitigate this.
Saturday night through most of Monday should be dry as surface high
pressure holds over the area and weak upper level ridging holds.
Sunday will begin the warming trend with highs warming into the mid
30s to low 40s. Highs on Monday will be much milder with a return of
southerly flow. The mercury should rebound to the low 50s in most
spots.
By Monday afternoon we will begin to focus on the next storm system
that looks to impact the area through Tuesday. This system will
develop as a lee surface low intensifies ahead of a digging trough
over the central Plains. At this point the low looks to move from
the southern Plains, northeastward either into the Ohio Valley or
just north to the lower Great Lakes through Tuesday morning. This
warmer solution would bring overrunning rain showers to the area
late Monday afternoon, with more widespread rain moving into the
area Monday night and early Tuesday. Temperatures will likely crash
quickly behind the system on Tuesday afternoon as sharp trough moves
through and may eventually have to mention rain changing to snow.
Will stick with all rain for now as it is too early to mention these
details, especially with the low track in question. Will also leave
any thunder mention out of the forecast with the bulk of the
precipitation as any moisture return/instability would be limited by
short duration of southerly flow. This system will have to be
watched however, as a more northerly solution or deeper sfc low
would change the instability picture. Also, chose to disregard the
more southern solution offered by the operational ECMWF. This seems
to be the outlier, with a general consensus between the GFS/GEM/GFS
ensemble mean/ECMWF ensemble mean of a northern solution.
&&
.Aviation (12Z TAF Issuance)...
Issued at 605 AM EST Wed Feb 13 2013
An upper level trough will pass through the area today with a sfc
low pressure passing to our south. Precipitation associated with
this weather system has already begun to spread northward into
central KY this morning. At the beginning of TAF time, it should be
raining near all TAF sites with SDF/LEX rains being more
intermittent showers until deeper moisture overtakes the low level
dry layer. After sunrise, good forcing will enter the region
causing steady moderate banded precip over the region. It`s hard to
say whether a moderate band will affect the TAF sites, but at least
feel confident enough to include lower MVFR conditions this morning
through early afternoon as the heavier precip moves through the
region. Some IFR cigs may be possible in some of the heavier bands
of precip especially near BWG but will not include in the TAF at
this time as confidence is low. Rain is expected to be the
predominant precip type for BWG, however, SDF/LEX could see a RASN
mix in a moderate band. A RASN mix isn`t out of the realm of
possibilities for BWG either, but seems most likely at SDF/LEX at
this time. Will need to adjust as the precip bands set up this
morning and move closer to our area. By mid to late afternoon,
precip should move east of the TAF sites with conditions returning
to high end MVFR and then VFR by this evening.
Winds will be predominantly NNE as the weather system moves through
the area this morning through mid afternoon. Winds will strengthen
throughout the day likely exceeding 7kt at times. Winds will shift
to the WNW behind this system by this evening.
NAM model soundings indicate a layer of low level moisture for
tomorrow morning which could indicate a light fog or low cigs. Will
not place flight restrictions at the end of the TAFs for now, but it
will be something to investigate further.
&&
.LMK WATCHES/WARNINGS/ADVISORIES...
IN...WINTER WEATHER ADVISORY UNTIL 4 PM EST /3 PM CST/ THIS AFTERNOON
FOR INZ076>079-083-084-089>092.
KY...WINTER WEATHER ADVISORY UNTIL 4 PM EST /3 PM CST/ THIS AFTERNOON
FOR KYZ023>034-038-045-053.
$$
Mesoscale........MJ
Short Term.......AMS
Long Term........BJS
Aviation.........AMS
AREA FORECAST DISCUSSION
NWS HASTINGS NE
1123 AM CST WED FEB 13 2013
.AVIATION...18Z TAF. WEST TO NORTHWEST WINDS WILL INCREASE THIS
AFTERNOON AND CONTINUE THROUGH THE NIGHT. DURING THE MORNING ON
THURSDAY THE WINDS WILL INCREASE FURTHER. VFR CONDITIONS ARE
EXPECTED THROUGH THE PERIOD.
&&
.PREV DISCUSSION... /ISSUED 453 AM CST WED FEB 13 2013/
SHORT TERM...THROUGH FRIDAY NIGHT. THE MAIN STORIES THROUGH THE
NEXT 72 HOURS INVOLVE A DOWNWARD TREND IN TEMPS AFTER A VERY MILD
ONE TODAY...STRONG NORTHWEST WINDS ON THURSDAY THAT MAY VERY WELL
REQUIRE A WIND ADVISORY ISSUANCE FOR AT LEAST PARTS OF THE
AREA...AND THE POSSIBILITY OF A FEW ROUNDS OF PASSING FLURRIES
DURING THE THURSDAY AFTERNOON THROUGH FRIDAY EVENING TIME FRAME
BUT WITH LITTLE...IF ANY RISK OF ACCUMULATING SNOW. IN
ADDITION...THE COMBINATION OF WARM AIR AND/OR GUSTY WINDS WILL
PROMOTE AT LEAST SOME ELEVATED...BUT LIKELY NON-CRITICAL...FIRE
DANGER IN PARTS OF THE AREA OVER THE NEXT FEW DAYS. THESE FIRE
WEATHER CONCERNS ARE FURTHER DISCUSSED IN THE SEPARATE SECTION
BELOW.
09Z CENTRAL PLAINS OBJECTIVE SURFACE ANALYSIS REVEALED A BROAD
AREA OF HIGH PRESSURE EXTENDING EASTWARD OUT OF THE ROCKIES...WITH
POSSIBLY A VERY SUBTLE TROUGH AXIS EXTENDING FROM FAR SOUTHEAST
NEB INTO SOUTHWEST KS. THIS REGIME WAS PROMOTING FAIRLY STEADY
5-10 MPH WESTERLY BREEZES ACROSS THE MAJORITY OF THE CWA...WHICH
ALONG WITH AN INCOMING BATCH OF HIGH LEVEL CLOUDS SHOULD KEEP MOST
AREAS UP INTO THE 21-25 DEGREE RANGE FOR MORNING LOW TEMPS.
ALOFT...WATER VAPOR IMAGERY AND SHORT TERM MODEL DATA SHOWED THE
CENTRAL PLAINS UNDER NORTH-NORTHWEST FLOW ALOFT...IN BETWEEN THE
SOUTHERN STREAM SHORTWAVE TROUGH ALONG THE MO/AR BORDER...AND A
PARADE OF LOW AMPLITUDE DISTURBANCES ASSOCIATED WITH THE NORTHERN
STREAM JET IN THE SOUTHWEST CANADA/MONTANA AREA. 11-3.9 MICRON
SATELLITE IMAGERY REVEALS CLEAR SKIES OVER MOST OF THE CWA BUT AT
LEAST A THIN LAYER OF HIGH CLOUD WILL BE PASSING OVER MOST OF THE
AREA BETWEEN NOW AND SUNRISE.
TODAY WILL BE THE WELL-ANTICIPATED WARMEST DAY OF THE WEEK FOR THE
ENTIRE CWA. ALOFT...NORTHWEST FLOW WILL PERSIST...WITH ONLY THE
MOST SUBTLE OF MOISTURE-STARVED DISTURBANCES RIDING THROUGH THE
FLOW AS THE AREA REMAINS JUST SOUTH OF A SLIGHTLY STRONGER WAVE
CROSSING THE DAKOTAS THIS AFTERNOON. AS A RESULT...SKY COVER WILL
BE SOMEWHAT VARIABLE TODAY...GENERALLY AVERAGING PARTLY CLOUDY BUT
ALTERNATING BETWEEN PERIODS OF PLENTIFUL SUNSHINE AND PASSING
BATCHES OF MID-HIGH LEVEL CLOUDS. AT THE SURFACE...THE WEST-
NORTHWEST WIND REGIME WILL PERSIST...AND INCREASE IN SPEED IN
RESPONSE TO DEEPENING MIXING TO AT LEAST THE 850-800MB LAYER. AS A
RESULT...UPPED WIND SPEEDS A BIT FROM PREVIOUS FORECAST...AS THE
LATE MORNING-LATE AFTERNOON HOURS WILL FEATURE SUSTAINED SPEEDS AT
LEAST 15-20 MPH WITH SOME GUSTS 25+ MPH. THE DEEP MIXING WILL
COMBINE WITH SLIGHTLY WARMER AIR MOVING IN ALOFT FROM THE WEST TO
RESULT IN HIGH TEMPERATURES WELL INTO THE 50S NEARLY ALL AREAS.
NUDGED UP HIGH TEMPS 2-3 DEGREES FROM PREVIOUS GRIDS IN MOST
AREAS...GETTING MOST PLACES UP BETWEEN 52-55 DEGREES EXCEPT
SLIGHTLY COOLER UPPER 40S MAINLY IN PARTS OF VALLEY COUNTY WHERE
SOME SNOW PACK REMAINS. THESE FORECAST HIGHS ARE RIGHT IN LINE
WITH 07Z RAP HOURLY TEMPS...WHICH HAVE PERFORMED QUITE WELL THE
PAST TWO DAYS.
TONIGHT...HAVE HIGH CONFIDENCE THAT IT WILL REMAIN PRECIP-
FREE...BUT THE LEADING EDGES OF A COLD FRONT WILL START BLEEDING
DOWN FROM THE NORTH...IN RESPONSE TO A PARADE OF NORTHWEST-FLOW
CLIPPER WAVES ALOFT THAT WILL FOCUS ALONG AN AXIS FROM NORTH
DAKOTA-IOWA. SKY COVER WILL REMAIN VARIABLE THROUGH THE NIGHT...AS
STEADY WEST-NORTHWEST BREEZES REMAIN UP BETWEEN 10-20 MPH WITH
SOME HIGHER GUSTS. DESPITE THE WEAK COLD AIR ADVECTION...THESE
WINDS AND PASSING CLOUDS SHOULD HAVE NO PROBLEM KEEPING OVERNIGHT
LOW TEMPERATURES AT LEAST SLIGHTLY WARMER THAN THOSE THIS
MORNING...AND MADE LITTLE CHANGE KEEPING MOST AREAS UP BETWEEN
25-29 DEGREES...AND WOULD NOT BE SURPRISED TO SEE A BIT GREATER
COVERAGE OF LOWS RIGHT AROUND 30 THAN CURRENTLY DEPICTED.
THURSDAY IS UNDOUBTEDLY THE MOST ACTIVE OF THE SHORT TERM
PERIODS...MAINLY DUE TO STRONG WINDS. SINCE 24 HOURS AGO...MOST
MODELS/GUIDANCE HAVE CONTINUED TRENDING UPWARD A BIT WITH
NORTHWESTERLY SPEEDS. FOCUSING FIRST ALOFT...AS THE DAY WEARS ON A
SMALL BUT FAIRLY VIGOROUS MID LEVEL SHORTWAVE TROUGH WILL DROP
SOUTHWARD OUT OF THE DAKOTAS INTO NEB/IA. MEANWHILE AT THE
SURFACE...THE PRESSURE GRADIENT WILL RAMP UP IN RESPONSE TO
INCREASING HIGH PRESSURE EMANATING FROM AN EXPANSIVE NORTHERN
ROCKIES RIDGE. ONCE DIURNAL MIXING KICKS IN AND LOW LEVEL LAPSE
RATES STEEPEN...THE 06Z NAM ADVERTISES MIXING TO DEEPEN WELL UP
INTO THE 800MB TO POSSIBLY 700MB RANGE...WITH AVERAGING WIND
SPEEDS THROUGH THIS MIXED LAYER EASILY SUPPORTING AT LEAST LOW-END
ADVISORY SUSTAINED SPEEDS BETWEEN 30-35 MPH AND GUSTS TO AROUND 45
MPH. WILL ADD THIS STRONG WIND MENTION TO THE HAZARDOUS WEATHER
OUTLOOK...BUT GIVEN IT IS STILL 3 PERIODS AWAY WILL HOLD OFF ON A
WIND ADVISORY FOR NOW...AND GIVE DAY SHIFT ANOTHER LOOK TO
DETERMINE WHETHER AN ADVISORY MAY BE JUSTIFIED FOR ALL 30
COUNTIES...OR MAINLY FOR THE NORTHERN 1/2 OF THE CWA WHICH LOOKS
SLIGHTLY MORE FAVORABLE TO MEET 30+ MPH FOR SEVERAL HOURS VERSUS
SOUTHERN ZONES. THE MAIN WINDOW FOR THE STRONGEST WINDS GENERALLY
LOOKS TO TARGET THE 11 AM-6 PM TIME FRAME. AS FOR PRECIP
CHANCES...HAVE NOTHING MENTIONED DURING THE MORNING...BUT HAVE RE-
INTRODUCED SOME FLURRY CHANCES FOR SOME AREAS NORTH OF I-80 DURING
THE AFTERNOON AS LOW LEVEL STRATUS SWEEPS IN FROM THE NORTH. NOT
THINKING ANYTHING ACCUMULATING AT THIS POINT...WITH BETTER CHANCES
FOR A LIGHT DUSTING FOCUSING JUST NORTH OF OUR AREA. TEMP-
WISE...IF IT WASN/T FOR THE WIND IT REALLY WOULDN/T FEEL TOO
BAD...AND ONLY MADE MINOR TWEAKS TO HIGHS RANGING FROM UPPER 30S
FAR NORTH...LOW 40S CENTRAL AND MID 40S IN KS ZONES.
TAKING A BIT BROADER LOOK AT THE THURSDAY NIGHT THROUGH FRIDAY
NIGHT TIME FRAME...THE BIG PICTURE ALOFT INVOLVES THE CENTRAL
PLAINS REMAINING UNDER NORTHWEST FLOW ALOFT AS A CONTINUING PARADE
OF MID LEVEL SHORTWAVE TROUGHS ROTATING SOUTH-SOUTHEAST OUT OF
CANADA WILL CARVE OUT AN EXPANSIVE LONGWAVE TROUGH THAT WILL
DOMINATE THE EASTERN TWO-THIRDS OF THE NATION. ON THURSDAY
NIGHT...THE INITIAL SHORTWAVE TROUGH WILL PASS JUST SOUTHEAST OF
OUR AREA...WHILE UPSTREAM THE NEXT MAIN ONE ENTERS THE DAKOTAS.
WIND SPEEDS WILL EASE DOWN QUITE A BIT...ESPECIALLY POST-MIDNIGHT
WHEN SPEEDS DECREASE INTO THE 5-10 MPH RANGE. ALTHOUGH SOME AREAS
MAY NOT SEE A SINGLE SNOWFLAKE...OPTED TO KEEP THE GRIDS AS SIMPLE
AS POSSIBLE AND BLANKET THE ENTIRE CWA WITH A SLIGHT CHANCE OF
FLURRIES ALL THE WAY FROM THURSDAY NIGHT THROUGH FRIDAY EVENING
AS THIS PATTERN OFTEN EVOKES SMALL-SCALE PATCHES OR BANDS OF NON-
MEASURABLE SNOW UNDERNEATH THE UPPER JET EXIT REGION...ESPECIALLY
IF SOME OF THE PASSING LOWER STRATUS HAS FAVORABLE DENDRITIC
TEMPERATURES. ALTHOUGH SUPPOSE A SMALL PERCENTAGE OF THE CWA COULD
SEE A LIGHT MEASURABLE DUSTING...ITS TOO EARLY TO DETERMINE WHERE
THIS MIGHT EVEN BE...SO CANNOT JUSTIFY A MEASURABLE 20+ POP
ANYWHERE AT THIS TIME FRAME. WINDS ON FRIDAY WILL REMAIN FROM THE
NORTH-NORTHWEST BUT DO NOT APPEAR NEARLY AS STRONG AS THURSDAY WITH
SUSTAINED SPEEDS GENERALLY TOPPING OUT AROUND 15 MPH. AS FOR
TEMPS...MADE ONLY A SMALL DOWNWARD NUDGE TO THURSDAY NIGHT WITH
MOST AREAS 16-20 DEGREES. FRIDAY STILL SHOULD BE THE COLDEST DAY
OF THE WEEK...BUT ACTUALLY NUDGED UP VALUES A BIT IN SOME AREAS
DUE TO DECENT MIXING POTENTIAL...RANGING FROM MID 30S IN MOST NEB
ZONES TO NEAR 40 IN KS. BY MIDNIGHT FRIDAY NIGHT...ANY FLURRY RISK
SHOULD BE OVER WITH AS THE BACK EDGE OF THE LAST IN A SERIES OF
MID LEVEL SHORTWAVE TROUGHS EXITS THE AREA.
LONG TERM...SATURDAY THROUGH TUESDAY. DRY CONDITIONS ARE FORECAST
THROUGH THE EXTENDED PERIODS. ON SATURDAY...THE PATTERN ALOFT WILL
FEATURE A TROUGH MOVING INTO THE PACIFIC NORTHWEST...RIDGING OVER
THE ROCKIES AND A LONGWAVE TROUGH FROM THE HUDSON BAY SOUTH TO THE
GULF COAST STATES. HEIGHTS WILL RISE ACROSS THE CENTRAL PLAINS OVER
THE WEEKEND AS THE WESTERN RIDGE BUILDS ONTO PLAINS AND THE COLD
AIRMASS ASSOCIATED WITH THE TROUGH TO THE EAST DEPARTS. THE RIDGE
BEGINS TO BREAK DOWN SUNDAY AS AN UPSTREAM TROUGH REACHES THE NORTH
CENTRAL ROCKIES. THIS NEXT TROUGH AND ASSOCIATED COLD FRONT CROSSES
THE CENTRAL PLAINS SUNDAY NIGHT/MONDAY...BRINGING ANOTHER ROUND OF
COLD AIR TO START THE WORKWEEK. TEMPERATURE WISE...TEMPS BEGIN TO
RECOVER ON SATURDAY BEHIND THE UPPER TROUGH...THEN SUNDAY WILL BE
THE WARMEST OF THE EXTENDED PERIODS WITH THE MILD AIRMASS IN PLACE
AHEAD OF THE NEXT APPROACHING COLD FRONT/SYSTEM. HIGHS SUNDAY ARE
LOOKING WELL ABOVE NORMAL IN THE 50S...THEN FOLLOWING COLD FROPA
TEMPS RETURN CLOSER TO FEBRUARY NORMALS FOR MON/TUES.
FIRE WEATHER...ALTHOUGH OUTRIGHT CRITICAL FIRE WEATHER
THRESHOLDS ARE CURRENTLY NOT FORECAST DURING THE NEXT FEW
DAYS...AT LEAST PARTS OF THE CWA BEAR WATCHING FOR SOME ELEVATED
TO NEAR-CRITICAL COMBINATIONS OF WIND AND RELATIVE HUMIDITY.
STARTING OFF TODAY...WEST-NORTHWEST SUSTAINED WIND SPEEDS WILL
AVERAGE 15-20 MPH IN NEARLY ALL AREAS...WITH SPORADIC TO FREQUENT
GUSTS TO 25+ MPH EXPECTED. FORTUNATELY...AFTERNOON RELATIVE
HUMIDITY VALUES ACROSS MOST OF THE ARE FORECAST TO HOLD SLIGHTLY
ABOVE CRITICAL LEVELS IN THE 25-30 PERCENT RANGE. HOWEVER...IT
COULD BE A CLOSE CALL ESPECIALLY IN PARTS OF PHILLIPS/ROOKS/OSBORNE
COUNTIES IN KANSAS...WHERE RH VALUES COULD EDGE A BIT CLOSER TO 20
PERCENT. WILL INTRODUCE AN ELEVATED FIRE DANGER MENTION INTO THE
HAZARDOUS WEATHER OUTLOOK MAINLY FOR THIS AREA. TURNING TO
THURSDAY...AS OUTLINED ABOVE STRONG SUSTAINED WINDS AROUND 30 MPH
OR HIGHER ARE FORECAST ACROSS NEARLY THE ENTIRE CWA.
FORTUNATELY...COOLER TEMPERATURES WILL KEEP AFTERNOON RH
PERCENTAGES ABOVE 30 PERCENT ACROSS NEBRASKA ZONES...BUT KS ZONES
COULD SEE VALUES CREEP DOWN CLOSER TO 25 PERCENT. BOTTOM LINE
IS...WHILE NO MAJOR FIRE DANGER ISSUES ARE ANTICIPATED THESE NEXT
FEW DAYS...SOME CAUTION MAY NEED TAKEN...AND HOURLY RELATIVE
HUMIDITY TRENDS THESE NEXT FEW AFTERNOONS WILL NEED WATCHED
CLOSELY TO MAKE SURE THERE ARE NO SURPRISES DROPPING BELOW 20
PERCENT.
&&
.GID WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
KS...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS GRAND FORKS ND
308 PM CST WED FEB 13 2013
.SHORT TERM...
CHALLENGE FOR THE PERIOD INCLUDE SNOW TODAY AND TONIGHT WITH
CLIPPER SYSTEMS AND THEN TEMPS THRU SATURDAY. MODELS IN OVERALL
GENERAL AGREEMENT WITH 12Z RUNS. 12Z GFS CAME AROUND IN AGREEMENT
WITH THE OVER MODELS WITH THE PLACEMENT OF TODAYS QPF. PRIMARILY
USED NAM/ECMWF FOR THE PACKAGE WITH A HEAVY LEAN TO THE RAP THRU
THIS EVENING.
CLIPPER CURRENTLY CROSSING THE CWFA IS PRODUCING VSBYS GENERALLY 1
TO 2 MILES WITH 1/2 MI IN THE STRONGEST SN. BACK EDGE OF CLIPPER
SNOW BAND JUST EXITING MINOT AREA. WILL CONTINUE WINTER WX ADVISORY
AS NEXT CLIPPER IS EXPECTED TO MOVE INTO THE DVL BSN THIS EVENING AND
STAY CONFINED TO THE WESTERN AND EXTREME SOUTHERN PORTIONS OF THE
CWFA. TOTAL 24 HOUR SNOWFALL WITH A 14 TO 1 RATIO IN THE QUARTER
TO HALF INCH QPF WILL BE IN THE 2 TO 5 INCH RANGE WITH A HIGHER
TOTAL ALONG A MADDOCK TO NEW ROCKFORD TO VALLEY CITY TO LISBON
LINE.
THE NEXT CONCERN WOULD BE WIND POTENTIAL ON THE BACK SIDE WITH BLOWING
SNOW IMPACTS. BEST COLD ADVECTION WILL LAG THE PRECIP BAND. NAM
INDICATES THE STRONGEST COLD PUSH OCCUR IN THE DVL BASIN AND ACROSS
THE WESTERN PORTIONS OF THE CWFA OVERNIGHT. THOUGH LOW LEVEL WINDS
ARE RELATIVELY WEAK WITH A SHALLOW MIXED LAYER JUST 10 TO 15 KTS
THROUGH 12Z. AS A RESULT LITTLE BLOWING SNOW IS EXPECTED.
MIXED LAYER INCREASES TOMORROW WITH BETTER MIXING...TO 20KTS TO
950MB TO 20KTS AS COLD AIR PUSHES IN WITH 925 TEMPS DROPPING 10 C
OR SO CAUSING DAYTIME TEMPS THURSDAY TO REMAIN FAIRLY STEADY OR EVEN
FALL THROUGH THE AFTERNOON.
SFC HIGH PRESSURE TO SLIDE ACROSS THE AREA FIR DAY WITH NW FLOW
ALOFT. COLD START AS NEGATIVE VALUES RETURN FOR MORNING LOWS.
LITTLE MIXING WILL LEAD TO SLOW TEMP RECOVERY FRIDAY. RETURN FLOW
SETS UP FRI AFTERNOON WEST AND WILL HELP OFFSET DIURNAL COOLING
VALLEY WEST FRIDAY NIGHT. TEMPERATURE MODERATION CONTINUES
SATURDAY AS WAA INCREASES WITH HIGHS IN THE TEENS AND 20S WEST.
.LONG TERM (SAT NIGHT-WED)...
MODELS IN REASONABLE AGREEMENT. NEXT SHORT WAVE MOVES THROUGH
SUNDAY AFTERNOON AND NIGHT. 12Z ECMWF IS COMING IN A BIT DEEPER
WITH 500 MB TROUGH AND FARTHER SOUTH WITH SFC LOW WHICH WOULD BE A
BIT HIGHER SNOW CHANCES OVER THE AREA THAN GFS/GEM. BEHIND THIS
SHORT WAVE THERE WILL BE STRONG COLD ADVECTION WITH 850 MB TEMPS
DROPPING INTO THE -18C TO -22C RANGE TUE-WED. CR ALL BLEND TEMPS
LOOK REASONABLE WITH HIGHS IN THE SINGLE DIGITS TUES-WED AND LOWS IN
THE 5 TO 15 BELOW RANGE. DISAGREEMENTS DO SHOW UP VERY LATE IN THE
PD FOR WED NIGHT-THU IN REGARDS TO NEXT 500 MB SYSTEM DIGGING INTO
THE CNTRL-SOUTHERN ROCKIES AND HOW FAR NORTH ITS IMPACT IS. GFS
WETTER AND FARTHER NORTH.
&&
.AVIATION...
AREAS OF SNOW TO IMPACT DVL-FAR REGION TONIGHT...WITH MOSTLY MVFR
VSBYS/CIGS...THOUGH BRIEF IFR VSBY PSBL. GFK-TVF-BJI TO BE ON DRY
SIDE OF THINGS AND SHOULD KEEP HIGH END VFR CLOUD DECK WITH SOME
AC/CI. WINDS WILL BE LIGHT THIS LATE AFTN BUT TURN NORTHERLY AND
INCREASE TO 10 TO 20 KTS WITH SOME HIGHER GUSTS ON THURSDAY AS COLD
ADVECTION INCREASES.
&&
.FGF WATCHES/WARNINGS/ADVISORIES...
ND...WINTER WEATHER ADVISORY UNTIL 9 AM CST THURSDAY FOR NDZ006-014-
015-024-026-028>030-038-039-049-052-053.
MN...WINTER WEATHER ADVISORY UNTIL 9 AM CST THURSDAY FOR MNZ003-
029>031-040.
&&
$$
JK/RIDDLE