Forecast Discussions mentioning any of
"HRRR" "RAP" "RR" "RUC13" "RUC" received at GSD on 02/26/13
AREA FORECAST DISCUSSION
NWS TUCSON AZ
915 AM MST SUN FEB 24 2013
.SYNOPSIS...LOW PRESSURE WILL MOVE ACROSS THE FOUR CORNERS TODAY
BRINGING ANOTHER SHOT OF COLD AIR TO SOUTHEAST ARIZONA ABOARD BRISK
NORTHWEST WINDS. SNOW SHOWERS WILL GENERALLY BE CONFINED TO AREAS
NEAR THE EASTERN MOUNTAINS. CLEARING AND COLD MONDAY MORNING. DRY
WITH A WARMING TREND MOST OF THE REST OF THE WEEK.
&&
.DISCUSSION...COLD FRONT CONTINUES TO SAG SOUTH ACROSS THE FORECAST
AREA THIS MORNING. BASED ON SURFACE OBSERVATIONS...THE FRONT
EXTENDED FROM NEAR CLIFTON TO JUST SOUTH OF TUCSON. OBS AND RADAR
INDICATED LIGHT SHOWERS WITH MOUNTAIN CAMERAS FROM CATALINAS TO THE
WHITES SHOWING SNOW SHOWERS. THIS AREA OF SHOWERS...BASED ON HRRR
AND RAP MODELS...SHOULD BE AROUND INTO THE AFTERNOON HOURS...THEN
OUT OF THE AREA BY THIS EVENING. OTHERWISE THE WIND AND MUCH COOLER
TEMPERATURES WILL BE THE MAIN STORY FOR TODAY. THE STRONGEST NW
WINDS WILL BE EAST OF TUCSON...ESPECIALLY IN NW-SE ORIENTED
VALLEY...WHERE GUSTS TO 45 MPH ARE POSSIBLE TODAY. HIGHS TODAY WILL
BE 10-15 DEGREES COLDER THAN SATURDAY WITH MOST LOCALS WILL
STRUGGLING TO GET OUT OF THE 40S AND LOW 50S. FORECASTS LOOK TO BE
IN GOOD SHAPE...SO NO UPDATED NEEDED AT THIS TIME.
&&
.AVIATION...WINDS ARE THE MAIN AVIATION CONCERN THROUGH THE TAF
PERIOD. GENERALLY LIGHT WINDS TO BEGIN THE DAY...BUT INCREASING
NORTHWESTERLY WINDS TO DEVELOP BY AROUND 18Z. AT KTUS...WIND GUSTS
NEAR 30 KTS POSSIBLE AFTER 20Z. STRONGEST WINDS EXPECTED AT KDUG
WITH GUSTS APPROACHING 40 KTS BY 21Z. KOLS WILL EXPERIENCE SIMILAR
WINDS AS KTUS. WINDS SHOULD DECREASE NEAR 02Z. MID CLOUD COVER ALSO
EXPECTED TODAY BUT SHOULD REMAIN IN THE VFR RANGE.
&&
.FIRE WEATHER...A COLD LOW PRESSURE SYSTEM DROPPING INTO NORTHERN
ARIZONA AND NEW MEXICO WILL CAUSE NORTHWEST WINDS THIS AFTERNOON
WITH SPEEDS EXCEEDING 30 MPH IN PORTIONS OF COCHISE AND GRAHAM
COUNTIES. MINIMUM HUMIDITY THRESHOLDS OF 15 PERCENT WILL BE
APPROACHED BRIEFLY BUT BE HELD IN CHECK BY THE COLDER TEMPERATURES.
THE FIRE DANGER RATING IS EXPECTED TO REMAIN LOW TO MODERATE AS THIS
SYSTEM PASSES THROUGH. WINDS SUBSIDING LATE TONIGHT WITH A RETURN TO
MORE AVERAGE WIND CONDITIONS ON MONDAY...ALTHOUGH TEMPERATURES WILL
REMAIN COOL.
&&
.TWC WATCHES/WARNINGS/ADVISORIES...
WIND ADVISORY FROM NOON TO 7 PM MST TODAY FOR AZZ507>509-511>514.
&&
$$
VISIT US ON FACEBOOK...TWITTER...YOUTUBE...AND AT WEATHER.GOV/TUCSON
AREA FORECAST DISCUSSION
NWS DENVER/BOULDER CO
946 AM MST SUN FEB 24 2013
.UPDATE...WINTER STORM HAS REALLY RAMPED UP THIS MORNING WITH
WIDESPREAD HEAVY SNOW FROM THE FRONT RANGE EASTWARD TO ABOUT
STERLING...AKRON...AND JUST WEST OF LIMON. BASED ON CURRENT
RADAR...SNOWFALL RATES...SPECTACULAR UPPER LEVEL DIVERGENCE NOTED
ON SATELLITE...AND RAP GUIDANCE...HAVE INCREASED SNOWFALL AMOUNTS
ANOTHER 2 INCHES FOR POINTS CLOSER TO THE FRONT RANGE WITH UP TO
4-6 INCHES MORE IN THE SOUTHERN FOOTHILLS. MEANWHILE...SHAVED A
COUPLE INCHES ACCUMULATION OVER THE FAR EASTERN PORTIONS OF THE
FORECAST AREA PER LATEST RADAR TRENDS/MODEL GUIDANCE.
&&
.AVIATION...SIGNIFICANT AVIATION IMPACTS WITH DECREASED ARRIVAL
RATES...VLIFR CONDITIONS...AND HEAVY SNOW/BLOWING SNOW THROUGH AT
LEAST 21Z. SHOULD SEE SLOW BUT GRADUAL IMPROVEMENT AT KDEN
THEREAFTER...BUT KAPA AND KBJC COULD VERY WELL STAY DOWN AT VLIFR
THROUGH 00Z. SNOW WILL THEN DECREASE WITH VISIBILITY GRADUALLY
IMPROVING THROUGH 07Z. TOTAL ACCUMULATIONS LIKELY NEAR 8 INCHES AT
KDEN...AND 10-12 INCHES AT KBJC AND KAPA.
&&
.PREV DISCUSSION... /ISSUED 417 AM MST SUN FEB 24 2013/
SHORT TERM...UPPER LOW OVER SOUTHEAST UTAH CONTINUES TO TRACK
SOUTHEASTWARD TOWARDS THE FOUR CORNERS. LATEST MODEL CONSENSUS
CONTINUES TO TRACK THIS LOW SOUTHEASTWARD DOWN ACROSS CENTRAL NEW
MEXICO BY THIS EVENING AND OUT ACROSS THE TEXAS PANHANDLE BY
MONDAY MORNING. MEANWHILE THE 850-700 MB LOW CONTINUES TO WIND UP
IN SOUTHEAST COLORADO AT THIS HOUR. CIRCULATION AROUND THIS
CYCLONE WILL BE INSTRUMENTAL IN PRODUCING THE IMPRESSIVE SNOW
AMOUNTS OFFERED BY THE VARIOUS MODELS DURING THE NEXT 12-18 HRS.
THERE/S STILL SOME CONCERN THAT THE MORE SOUTHERLY TRACK OF THE
UPPER LOW WILL LIMIT THE LIFT AND THUS THE SNOW AMOUNTS ACROSS
THE FCST AREA. HOWEVER...MODELS...NOTABLY THE LATEST RUC...
CONTINUE TO CRANK OUT RESPECTABLE SNOW AMOUNTS IN AND NEAR THE
FRONT RANGE AND ESPLY OVER THE PALMER DIVIDE BY 00Z/MONDAY...AND
EVEN A BIT MORE ACCUMULATION ALONG THE PALMER DIVIDE THIS EVENING.
IN ADDITION TO THE MODERATE TO HEAVY SNOWFALL ANTICIPATED EAST OF
THE MTNS THIS MORNING THRU EARLY THIS AFTERNOON...MODELS ARE
STILL GENERATING STRONG NORTH-NORTHEAST SFC WINDS ON THE PLAINS
NEXT 12-18 HOURS IN RESPONSE TO THE DEEPENING LOW IN SERN
COLORADO. SPEEDS OF 30-40KTS LOOK BELIEVABLE FOR LATER THIS
MORNING INTO THE AFTERNOON IN THE AREA COVERED BY A BLIZZARD
WARNING. SNOWFALL HAS YET TO DEVELOP IN THIS AREA...BUT STILL
COUNTING ON IT BEGINNING WITHIN THE NEXT HOUR OR TWO. AS FOR THE
HIGH COUNTRY...THIS WAS NEVER MEANT TO BE A BIG SNOW PRODUCER FOR
AREAS WEST OF THE CONTINENTAL DIVIDE. ALTHOUGH SHOULD STILL
RECEIVE ENOUGH SNOW TO WARRANT HANGING ONTO THE WINTER WEATHER
ADVISORY UP THERE. LASTLY...EXTENDED THE WINTER STORM AND
BLIZZARD WARNING ON THE PLAINS TO 06Z TONIGHT...BUT WILL ALLOW
THE WINTER WEATHER ADVY IN THE MTNS AND NORTHEAST PLAINS TO
EXPIRE ON TIME.
LONG TERM...THE UPPER LOW WILL BE OVER THE TEXAS PANHANDLE
MONDAY MORNING BUT THERE IS STILL SOME MOISTURE OVER SOUTH AND
EASTERN PORTIONS OF THE CWA. WILL ADD SOME LOW POPS OVER THE
PALMER DIVIDE REGION DUE TO THE NORTHERLY FLOW EARLY MON AM AND
SLOWER TRACK OF THE STORM.
WEAK RIDGING ALOFT FOR MONDAY EVENING BUT NEXT TROF IS COMING IN
ON ITS HEELS FOR TUESDAY AND TUESDAY NIGHT. THIS NEXT ONE IS
STILL COMING IN AS AN OPEN WAVE SO THE MOUNTAINS LOOK TO BE THE
MAIN BENEFICIARY. HOWEVER THERE IS STILL SOME DECENT UPWARD ASCENT
MOVING OVER CENTRAL COLORADO AND INSTABILITY WITH THIS WAVE.
CHANCES OF PRECIP OVER THE PLAINS WOULD FAVOR THE PALMER DIVIDE
REGION WITH THE MODEST NORTHERLY FLOW. WILL MAINTAIN 20-30 POPS
OVER THE PLAINS THROUGH TUESDAY AFTERNOON AND NIGHT OVER THE
PLAINS. ANOTHER WEAK SYSTEM ON THURSDAY WHICH WILL AGAIN FAVOR THE
MOUNTAINS BUT NOT MUCH MOISTURE TO WORK WITH OVER EASTERN
COLORADO. TEMPERATURES WILL REMAIN BELOW NORMAL THROUGH THURSDAY
WITH THE UNSETTLED PATTERN. BROAD RIDGING ALOFT BUILDS ACROSS
THE REGION FOR FRIDAY THROUGH SUNDAY WITH A DRYING AND WARMING
TREND.
AVIATION...LIFR AND IFR CONDITIONS IN SNOW AND BLOWING SNOW
THROUGH THE DAY. NORTHERLY WINDS OF 20-30KTS AFTER 16KTS WILL
PRODUCE BLOWING AND DRIFTING SNOW. SNOW AND BLOWING SNOW WILL
POTENTIALLY PRODUCE VISIBILITIES TO NEAR ZERO AT TIMES.
CONDITIONS WILL GRADUALLY IMPROVE THIS EVENING...ADD RETURN TO
MVFR AFTER MIDNIGHT AS THIS LATEST STORM SYSTEM PULLS AWAY FOR
THE FRONT RANGE.
&&
.BOU WATCHES/WARNINGS/ADVISORIES...
WINTER WEATHER ADVISORY UNTIL 5 PM MST THIS AFTERNOON FOR COZ031-
033-034-038-042-048-050-051.
WINTER STORM WARNING UNTIL 5 PM MST THIS AFTERNOON FOR COZ035-
043-044.
WINTER STORM WARNING UNTIL 8 PM MST THIS EVENING FOR COZ039-040.
WINTER STORM WARNING UNTIL 11 PM MST THIS EVENING FOR COZ036.
BLIZZARD WARNING UNTIL 11 PM MST THIS EVENING FOR COZ041-045>047-
049.
&&
$$
SHORT TERM...BARJENBRUCH
LONG TERM....ENTREKIN
AVIATION...BARJENBRUCH
AREA FORECAST DISCUSSION
NWS DENVER/BOULDER CO
944 PM MST SAT FEB 23 2013
.UPDATE...
&&
.SHORT TERM...SNOW STARTING TO DEVELOP ALONG THE FRONT RANGE AS
LIFT MOVES IN AND PRESSURE FALLS MOVE INTO SOUTHERN COLORADO.
INTENSITY WILL BE LOW INITIALLY...PARTLY DUE TO DRY LOW LEVEL AIR
THAT WILL TAKE SEVERAL HOURS TO SATURATE. BUMPED UP THE TIMING OF
SNOW BEGINNING TO REFLECT WHAT IS HAPPENING...BUT NOT MUCH CHANGE
TO THE EXPECTED INTENSIFICATION LATER TONIGHT.
MODEL TRENDS CONTINUE TO BE A LITTLE STRONGER/SLOWER WITH A BIT
MORE SNOW...MAINLY DUE TO THE SNOW ENDING LATER. LATEST RUNS
SUGGEST ANOTHER INCH OR TWO IN THE DENVER AREA SUNDAY
EVENING...WITH SREF ENSEMBLES SUGGESTING 7-14 INCHES ACROSS DENVER
AND SEVERAL MEMBERS OVER 20 INCHES AT KAPA. THE SLOWER SPEED WOULD
ESPECIALLY IMPACT AREAS SOUTH OF DENVER WHERE THE SNOW RATES WOULD
STILL BE GOOD WITH THE UPSLOPE WIND. WE MAY NEED TO MOVE THE
FORECAST IN THAT DIRECTION...BUT WILL WAIT FOR MORE CONFIDENCE ON
THAT...LITTLE IMPACT ON THE CURRENT WARNINGS ANYWAY.
&&
.AVIATION...LITTLE CHANGE. SNOW BECOMING WIDESPREAD BY 08Z WITH
MVFR CONDITIONS PREVAILING...THEN LIFR CONDITIONS PREVAILING BY
12Z. 06Z TAFS WILL HAVE STRONGER WINDS SUNDAY
AFTERNOON...EXPECTING BLIZZARD CONDITIONS FOR SEVERAL HOURS AT
KDEN AND POSSIBLY KAPA...KBJC WILL LIKELY STAY LIFR BUT WILL
LIKELY HAVE LESS WIND AND VISIBILITY IMPACT. SOME SNOW
ACCUMULATION AND BLOWING/DRIFTING CONTINUING INTO SUNDAY EVENING
THEN MUCH BETTER BY 06Z MONDAY AT KBJC/KDEN AND 08Z AT KAPA.
&&
.PREV DISCUSSION... /ISSUED 330 PM MST SAT FEB 23 2013/
SHORT TERM....CURRENT WATER VAPOR AND Q-G ANALYSIS SHOWS A
STRONG STORM SYSTEM CARVING OUT ACROSS THE GREAT BASIN. LATEST
MODEL TRENDS FROM THE 12Z NAM...GFS...GEM AND EVEN WRF HAVE SHOWN
A SLIGHT NORTHWARD SHIFT IN AREAS OF BEST LIFT AND HEAVIER
SNOWFALL. HOWEVER...12Z ECMWF STILL MAINTAINED A PERSISTENT AND
PREFERRED SOLUTION BUT AT THE SAME TIME HAS INCREASED SNOWFALL
AMOUNTS AN INCH OR TWO MORE THAN THE 00Z RUN. NCEP FORECASTERS
WITH ACCESS TO 00Z EC ENSEMBLE MEMBERS NOTED THAT SOME UNCERTAINTY
EVEN REGARDED THE SLIGHTLY FARTHER SOUTH ECMWF SOLUTION...BUT Q-G
HEIGHT FALL ANALYSIS FROM THE RUC INDICATES THE OPERATION ECMWF
SEEMS QUITE REASONABLE. THE ONLY ARGUMENT WOULD BE IF A MID LEVEL
CIRCULATION CENTER PERHAPS RELATED TO LARGER LATENT HEAT RELEASE
WOULD RESULT IN A MORE NORTHERLY SOLUTION. AT THIS TIME...HAVE
STILL LEANED HEAVILY TOWARD THE ECMWF...BUT ALSO INCORPORATED A
BIT OF THE MESOSCALE/SREF MODEL SOLUTIONS.
ALL OF THESE FACTORS ADD UP TO A HIGH POTENTIAL FOR A HEAVY SNOW
EVENT. THEY INCLUDE...NEUTRAL STABILITY PROFILES...AVERAGE OF
25-30 KTS OF NNE UPSLOPE FLOW...DEEP UPSLOPE COMPONENT WELL ABOVE
MOUNTAIN TOP...GOOD MICROPHYSICS WITH LARGE OMEGA THROUGH THE
DENDRITIC GROWTH REGION...AND A 12-18 HOUR PERIOD OF MODERATE Q-G
VERTICAL MOTION. THIS ALL SUPPORTS THE UPGRADE OF BLIZZARD WATCHES
TO WARNING...WINTER STORM WATCHES TO WINTER STORM WARNINGS...AND
MOST OTHER LOCATIONS TO WINTER WEATHER ADVISORIES FOR SNOW AND
BLOWING SNOW. THE OVERALL BLENDING USING A MAJORITY OF THE ECMWF
WITH A LITTLE BIT OF MESOSCALE/SREF MODELS SUPPORT THE FOLLOWING
AMOUNTS...6-10 INCHES FOR DENVER/BOULDER AREA...8-12 INCHES PALMER
DIVIDE...7-14 INCHES FOOTHILLS...AND 4-8 INCHES THROUGH SOUTHERN
WELD...MORGAN...TOWARD WASHINGTON/LINCOLN COUNTY.
LONG TERM...THE BRUNT OF SUNDAY`S STORM SHOULD BE GETTING CLOSE
TO ENDING BY THE BEGINNING OF THE LONG TERM PERIOD 25/00Z. THERE
WILL PROBABLY STILL BE SOME SNOW OVER THE SOUTHEAST THIRD OR SO OF
THE CWA DURING THE EVENING BUT THAT WILL FLUSH OUT TOWARDS MORNING.
SURFACE PRESSURE GRADIENTS WILL REMAIN SUFFICIENT TO KEEP GUSTY
WINDS OVER MANY LOWER ELEVATIONS IN THE EVENING BUT THESE TOO WILL
SETTLE DOWN OVERNIGHT. ONLY A QUICK BREAK IN THINGS AS A SHORT
WAVE RIDGE MOVES IN FOR MONDAY WITH THE NEXT PACIFIC SYSTEM
IMPACTING OUR WEATHER ON TUESDAY. THIS WILL BE MAINLY A MOUNTAIN
EVENT BUT ENOUGH QG LIFT BLEEDS OVER THE HILLS TO BRING A THREAT
OF PRECIPITATION TO THE PLAINS TUESDAY. ANOTHER WEAKER SYSTEM IS
PROGGED TO PUSH OVER THE CENTRAL ROCKIES THURSDAY...AGAIN BEING
MAINLY A PRECIPITATION PRODUCER FOR THE HIGH COUNTRY. TEMPERATURES
WILL REMAIN BELOW NORMAL THROUGH MOST OF THE WEEK BUT SHOULD
APPROACH NORMAL TOWARD WEEK`S AS A STRONG RIDGE ALOFT BUILDS INTO
THE GREAT BASIN. THE MOUNTAINS AND FOOTHILLS WILL ALSO EXPERIENCE
SOME WINDY PERIODS AS THE FLOW ALOFT BECOMES NORTHWESTERLY.
AVIATION...SIGNIFICANT AVIATION IMPACTS EXPECTED FROM THIS
WINTER STORM. CEILINGS AND VISIBILITIES WILL TUMBLE TONIGHT AND
REMAIN VERY LOW THROUGH MOST OF SUNDAY. ONSET TIMING OF THIS IS
STILL RATHER DIFFICULT...BUT WE SHOULD SEE SNOW DEVELOPING IN THE
FRONT RANGE AIRPORTS MOST LIKELY BETWEEN 05Z AND 08Z...WITH VLIFR
CONDITIONS BY 09Z-11Z WHEN SNOWFALL RATES INCREASE TO AROUND 1
INCH PER. THE HEAVY SNOW WILL LIKELY CONTINUE THROUGH ABOUT 20Z
SUNDAY BEFORE CONDITIONS SLOWLY IMPROVE. GUSTS UP TO 30 KTS AT
KDEN WITH CONSIDERABLE BLOWING AND DRIFTING SNOW AND POOR
VISIBILITIES CLOSE TO ONE QUARTER MILE FOR SEVERAL HOURS DURING
THE HEAVIEST SNOW 11Z-20Z...THEN GRADUAL IMPROVEMENT.
&&
.BOU WATCHES/WARNINGS/ADVISORIES...
WINTER WEATHER ADVISORY FROM 5 AM TO 5 PM MST SUNDAY FOR COZ048-
050-051.
WINTER STORM WARNING UNTIL 5 PM MST SUNDAY FOR COZ035-036-039-
040.
WINTER WEATHER ADVISORY UNTIL 5 PM MST SUNDAY FOR COZ031-033-034.
WINTER WEATHER ADVISORY UNTIL 5 PM MST SUNDAY FOR COZ038-042.
WINTER STORM WARNING FROM 2 AM TO 5 PM MST SUNDAY FOR COZ043-044.
BLIZZARD WARNING FROM 2 AM TO 5 PM MST SUNDAY FOR COZ041-045.
BLIZZARD WARNING FROM 5 AM TO 5 PM MST SUNDAY FOR COZ046-047-049.
&&
$$
SHORT TERM...BARJENBRUCH
LONG TERM....ET
AVIATION/UPDATE...GIMMESTAD
AREA FORECAST DISCUSSION
NWS JACKSONVILLE FL
250 PM EST SUN FEB 24 2013
...MODERATE TO LOCALLY HEAVY RAINFALL POSSIBLE LATE TONIGHT INTO
TUESDAY...
...A SLIGHT RISK OF SEVERE THUNDERSTORMS MONDAY THRU TUESDAY...
.CURRENTLY...STATIONARY FRONT NOTED OVER N CENTRAL FL WITH WEAK LLVL
CONVERGENCE NOTED OVER MARION COUNTY. ALOFT...WEAK IMPULSE NOTED
ABOUT 200 MI TO THE WSW OF OCF MOVING ENE WHICH WILL HELP TRIGGER A
FEW SHOWERS AND POSSIBLE STORMS THIS AFTERNOON MAINLY OVER INLAND NE
FL.
.SHORT TERM...
TONIGHT...AS A POTENT CLOSED MID/UPPER LEVEL LOW EJECTS OUT OF THE
SW U.S...THE NEARLY STATIONARY FRONT OVER N CENTRAL FL WILL BEGIN TO
DRIFT BACK NWD AS A WARM FRONT THANKS TO INCREASING SWLY FLOW ALOFT.
A FEW THUNDERSTORMS ARE POSSIBLE OVER THE INLAND NE FL ZONES THIS
EVENING AND MAY CONTINUE TO BE A LOW END CHANCE OVER INLAND ZONES
AFTER MIDNIGHT AS STRONGER FORCING IS REALIZED AS UPPER LEVEL
IMPULSES RIDE ENEWD THROUGH THE CWA. LOWS NEAR 50 N ZONES TO AROUND
60 S ZONES. FOR LATE TONIGHT...HAVE INCLUDED A MENTION OF LOCALLY
HEAVY RAINFALL NEAR THE SUWANNEE VALLEY AREA BASED ON SREF GUIDANCE
AND LATEST RAP FCSTS.
MONDAY...WARM FRONT EXPECTED TO MOVE UP TO NRN FL NEAR I-10 CORRIDOR
AND WILL NOT BUDGE MUCH WITH NMRS TO WIDESPREAD PRECIPITATION...
HEAVY AT TIMES ESPECIALLY OVER SE GA AND HAVE INCLUDED HEAVY
RAINFALL WORDING THERE. RAINFALL AMOUNTS OF 1-2 INCHES POSSIBLE IN
SE GA BUT AT THIS TIME DOES NOT QUITE WARRANT ANY FLOOD WATCHES.
TEMPS WILL BE HELD DOWN BY CLOUDS AND PRECIP WITH 60S N TO UPPER 70S
S ZONES. MONDAY NIGHT...THE BOUNDARY WILL LIFT NWD AS AFOREMENTIONED
MID/UPPER LEVEL LOW MOVES NEWD THROUGH THE MID MS VALLEY...WITH A
TRAILING COLD FRONT MOVING FROM ERN LA AT 00Z TUE TO ABOUT THE
TALLAHASSEE AREA BY 12Z TUE. PRECIP COVERAGE WILL CONTINUE TO BE
HIGH OVER SE GA IN THE EVENING...THEN GRADUAL LESSENING AS THE WARM
FRONT LIFTS NWD AND LIFT WEAKENS SLIGHTLY. THERE WILL BE A POTENTIAL
FOR STRONG/LOCALLY SEVERE TSTMS WITH INCREASING DEEP LAYER SHEAR.
LOWS AROUND 60 TO 65 WILL PREVAIL FOR MONDAY NIGHT.
TUESDAY...THERE CONTS TO BE SOME DISAGREEMENT WITH FRONTAL TIMING
THROUGH OUR CWA WITH THE NAM SLOWER THAN THE GFS AND ECMWF. HAVE
LEANED TOWARD A LITTLE FASTER SOLUTION THAN THE NAM. WE ANTICIPATE
LIKELY SHOWER CHANCES EARLY TUESDAY WITH SCT TSTMS POTENTIAL AS THE
FRONT PRESSES THROUGH THE AREA. THE FRONT IS EXPECTED TO PUSH
OFFSHORE IN THE AFTN WITH RAIN CHANCES DIMINISHED BY MID TO LATE AFTN.
A PREFRONTAL SQUALL LINE IS LIKELY WITH POSSIBLY OF STRONG TO SEVERE
STORMS THOUGH INSTABILITY AS IS TYPICALLY THE CASE IS WEAK BUT
SUFFICIENT FOR SOME STRONG STORMS. THE STORM PREDICTION CENTER HAS
OUR FORECAST AREA IN A SLIGHT RISK FOR SEVERE THUNDERSTORM
DEVELOPMENT. HIGHS WILL CLIMB INTO THE 70S AHEAD OF THE FRONT.
SOUTHWEST SURFACE WINDS MAY APPROACH LAKE WIND ADVISORY CRITERIA
OVER OUR ERN ZONES AFTER SUNRISE ON TUES.
TUESDAY NIGHT THROUGH WED...WEAK HIGH PRES WILL BUILD INTO THE
REGION WITH A MUCH DRIER AIRMASS. NOT VERY COLD BEHIND THE FRONT WITH
LOWS TUE NIGHT IN THE MID 40S TO LOWER 50S AND HIGHS WED NEAR
CLIMATOLOGY AROUND UPPER 60S TO LOWER 70S. PREVAILING LLVL FLOW FROM
THE SW AND W AROUND 10-15 MPH.
.LONG TERM...WED NIGHT-SUN.
GLOBAL MODELS ARE IN GENERAL AGREEMENT THAT AN AMPLIFIED MID/UPPER
PATTERN WILL EXIST DURING THE EXTDD PERIOD WITH A STRONG RIDGE
BUILDING INTO THE ROCKIES AND BROAD TROUGHING LOCATED OVER THE ERN
CONUS. MEAN W TO NW FLOW EXPECTED FOR THE FORECAST AREA WITH A
SERIES OF REINFORCING COLD FRONTS OVER THE SE STATES. A ~995 MB SFC
LOW INITIALLY OVER THE OHIO VALLEY TO PA AREA WILL SHIFT EWD AND
INTO THE WRN ATLC BY THE WEEKEND. THE MODELS SHOW WITH DIFFERING
STRENGTHS AND LOCATION A STRONG SHORTWAVE TROUGH (S) AND SOME
INCREASE IN MOISTURE DROPPING S-SE ON THE WRN SIDE OF THE MEAN LAYER
TROUGH. THIS MAY AFFECT THE SE CONUS LATE FRI THROUGH THE
WEEKEND...WITH A HINT OF POSSIBLE SHOWERS FROM THIS FEATURE IN OUR
CWA BUT CHANCES SEEM BELOW 15% ATTM. CONFIDENCE IN BELOW NORMAL
TEMPS IS HIGH...WITH FREEZES CERTAINLY POSSIBLE FOR INTERIOR
LOCATIONS NEXT WEEKEND DEPENDING ON THE PLACEMENT OF SURFACE RIDGING
OVER THE SOUTHEASTERN STATES. HIGH TEMPERATURES WILL LIKELY REMAIN
IN THE 50S NEXT WEEKEND...WITH PERSISTENT BREEZY NORTHWESTERLY WINDS.
&&
.AVIATION...PREVAILING VFR THIS EVE. WARM FRONT LIFTING INTO THE
AREA BY LATE TONIGHT WILL PRODUCE WIDESPREAD SHOWERS ALONG WITH MVFR
AND POSSIBLY IFR CONDITIONS AT ALL TERMINALS. MVFR CONDITIONS
POSSIBLE IN GNV BY 04Z.
.MARINE...A WARM FRONT WILL LIFT NORTH ACROSS THE WATERS BY LATE
MONDAY. WINDS WILL INCREASE TO SCA OFFSHORE BY MONDAY AFTERNOON
AND THEN CONTINUE AT SCA AND VEER TO THE SOUTH BY TUESDAY WITH THE
APPROACH OF THE COLD FRONT AND THEN SHIFT TO WEST TUESDAY NIGHT
FOLLOWING THE FRONTAL PASSAGE. WIDESPREAD SHOWERS ARE EXPECTED LATE
TONIGHT INTO MONDAY WITH NUMEROUS SHOWERS AND AND SCATTERED STORMS
MONDAY NIGHT AND TUESDAY WITH THE COLD FRONT. WIND AND SEAS MAY BE
HIGHER IN AND NEAR SHOWERS AND STORMS. SCEC TO SCA CONDITIONS WILL
PERSIST FOR THE MUCH OF THE LATTER HALF OF THE WEEK.
RIP CURRENTS: LOW RISK TODAY, MODERATE RISK MONDAY WITH INCREASING
ONSHORE FLOW.
&&
.PRELIMINARY POINT TEMPS/POPS...
AMG 51 61 59 74 / 60 100 90 60
SSI 56 62 60 73 / 60 100 100 60
JAX 56 68 62 78 / 70 90 90 60
SGJ 60 70 66 76 / 60 70 70 60
GNV 58 74 62 76 / 60 70 60 70
OCF 61 78 62 78 / 50 60 60 60
&&
.JAX WATCHES/WARNINGS/ADVISORIES...
FL...NONE.
GA...NONE.
AM...SMALL CRAFT ADVISORY FROM NOON MONDAY TO 4 AM EST WEDNESDAY FOR
ALTAMAHA SOUND GA TO FERNANDINA BEACH FL 20 NM TO 60 NM
OFFSHORE-FERNANDINA BEACH TO ST AUGUSTINE FL 20 NM TO 60 NM
OFFSHORE-ST AUGUSTINE TO FLAGLER BEACH FL 20 NM TO 60 NM
OFFSHORE.
&&
$$
SHASHY/PETERSON/CHASE
AREA FORECAST DISCUSSION...UPDATED
NWS PEACHTREE CITY GA
1240 AM EST SUN FEB 24 2013
...UPDATE...
NO CHANGES WERE MADE TO MORNING FORECAST EXCEPT TO LET DENSE FOG
ADVISORY EXPIRE.
41
.PREV DISCUSSION... /ISSUED 349 AM EST SUN FEB 24 2013/
..DENSE FOG ADVISORY IN EFFECT THIS MORNING...
..FLOOD WATCH IN EFFECT FOR PORTIONS OF NORTH AND ALL OF CENTRAL
GEORGIA MONDAY THROUGH TUESDAY...
SHORT TERM /TODAY THROUGH MONDAY NIGHT/...
LATEST REGIONAL RAP ANALYSIS INDICATES FRONTAL BOUNDARY HAS MADE
ITS WAY THROUGH THE FORECAST AREA WITH NW FLOW AT THE SURFACE.
MOISTURE...ESPECIALLY AT THE EXTREME LOW LEVELS HAS BEEN MUCH
SLOWER TO DEPART RESULTING IN DENSE FOG ACROSS THE REGION. HAVE
BEEN TRACKING TWO SEPARATE AREAS OF DENSE FOG...BOTH OF WHICH ARE
TRANSIENT MAKING THE FORECAST CHALLENGING TO SAY THE LEAST AS FAR
AS VISIBILITY IS CONCERNED THROUGH DAYBREAK. HAVE OPTED TO GO WITH
A DENSE FOG ADVISORY FOR THE ENTIRE AREA AND AS CONDITIONS IMPROVE
THROUGH DAYBREAK...CANCEL COUNTIES OUT AS NECESSARY.
TODAY LOOKS TO BE A TRANSITION DAY ACROSS THE AREA...A MUCH NEEDED
BREAK FROM RECENT RAINFALL ACROSS THE SOUTHERN TIER ALTHOUGH
FLOODING WILL BE ONGOING. SOME 5 INCHES OF RAIN IN AREAS FROM
PREVIOUS SYSTEM AND HAVE AREAL FLOOD WARNING IN EFFECT FOR CRISP
COUNTY. WILL SEE FRONT FRONT SETTLE ACROSS NORTH FLORIDA WITH HIGH
PRESSURE BUILDING IN OVER THE OHIO VALLEY AND RIDGING THROUGH
TENNESSEE AND THE LOCAL FORECAST AREA. FLOW ALOFT LOOKS TO REMAIN
ZONAL TO SLIGHTLY RIDGING AND ONCE LOW CLOUDS CLEAR...WE SHOULD
SEE A STELLAR END TO THE WEEKEND WITH TEMPS IN THE 60S AND EVEN A
FEW LOW 70S TO THE SOUTH.
RESPITE FROM THE RAIN LOOKS QUITE SHORT LIVED AS POTENT SHORTWAVE
DIVES INTO THE SOUTHERN PLAINS CREATING A LARGE SCALE DIFFLUENT
FLOW ALOFT FOR THE SOUTHEAST. ADD TO THIS RIPPLES EMBEDDED IN THE
ZONAL FLOW AND SHOULD SEE AREA OF MODERATE RAIN DEVELOP ACROSS THE
SOUTHERN TIER BY MONDAY MORNING. WITH WEDGE STRENGTHENING OVER THE
CAROLINAS...ADIABATIC OMEGA BECOMES MAXIMIZED DURING THE DAY
MONDAY WITH NEAR CATEGORICAL POPS ANTICIPATED AREA WIDE. WILL
DISCUSS FLOOD IMPLICATIONS FURTHER IN HYDROLOGY SECTION.
BY MONDAY NIGHT...WARM FRONT WILL PUSH INTO THE SOUTHERN MOST
COUNTIES WITH LIMITED SURFACE INSTABILITY BUT INCREASED LOW LEVEL
HELICITY. APPEARS AT THIS POINT THAT SEVERE THREAT WILL BE
ISOLATED AT BEST BUT STILL HAVE A FEW ANALOGS WHICH POINT TO
POTENTIAL ISOLATED TORNADO DEVELOPMENT MONDAY NIGHT INTO TUESDAY
MORNING. SREF ADDS SOME VALIDITY TO THIS WITH PROBABILITY OF 50
PERCENT OF STP OF 1 OR GREATER TUESDAY MORNING.
DEESE
LONG TERM /TUESDAY THROUGH SATURDAY/...
GFS AND ECMWF MODELS SIMILAR THROUGH THE EXTENDED FORECAST PERIOD
CONCERNING THE LARGE SCALE PATTERN. RAIN LIFTING OUT OF THE FORECAST
AREA THROUGH THE DAY TUESDAY AS THE MAIN UPPER LOW AND ASSOCIATED
SURFACE LOW LIFT INTO THE EASTERN OHIO VALLEY. UPPER PATTERN THROUGH
THE MAJORITY OF THE REMAINDER OF THE EXTENDED FORECAST PERIOD
DOMINATED BY MODERATE TO STRONG NORTHWESTERLY FLOW AS BROAD BUT DEEP
UPPER TROUGH LINGERS OVER THE EASTERN U.S. TIGHT SURFACE PRESSURE
GRADIENT PERSISTS AS WELL THROUGH THE PERIOD WITH MODERATE TO STRONG
NORTHWESTERLY FLOW PERSISTING. GFS KEEPS LOW QPF ALONG OUR FAR
NORTHERN COUNTIES WEDNESDAY THROUGH SATURDAY WHILE THE ECMWF KEEPS
THE ENTIRE FORECAST AREA DRY THROUGH ALL BUT THURSDAY. HAVE KEPT THE
PREVIOUS TREND OF SLIGHT CHANCE POPS AND VERY LOW QPF FOR THE FAR
NORTH WEDNESDAY THROUGH SATURDAY. MODEL THICKNESSES AND TEMPERATURES
WOULD INDICATE A CHANCE FOR MIXED PRECIPITATION THROUGH THE
PERIOD...ALTHOUGH WITH THE LOW CHANCES AND LIMITED MOISTURE AVAILABLE
ANY AMOUNTS WOULD LIKELY BE VERY SMALL. THIS TREND WILL NEED TO BE
WATCHED CLOSELY AS WE MOVE INTO THE MIDDLE OF THE WEEK. HOWEVER THIS
PATTERN DOES POINT TO A PERIOD OF BELOW NORMAL TEMPERATURES THROUGH
THE EXTENDED FORECAST PERIOD.
20
HYDROLOGY...QPE FROM PREVIOUS EVENT INDICATES 2 INCHES OF RAIN
FELL FROM ROUGHLY THE ATLANTA METRO TO AS MUCH AS 4 INCHES FOR THE
SOUTHERN TIER. SAME AREA IS TARGETED FOR THIS EVENT WITH AN
ADDITIONAL 2 TO 3 INCHES EXPECTED AND HAVE ISSUED A FLOOD WATCH
THROUGH TUESDAY EVENING.
&&
.AVIATION...
18Z UPDATE...
VFR FORECAST INTO THE OVERNIGHT HOURS WITH NORTHWEST WINDS 5 TO 8KT.
CONDITIONS LOWERING TO MVFR BEYOND SUNRISE MONDAY AS NEXT RAIN
PRODUCING SYSTEM STARTS TO MOVE INTO THE LOWER MISSISSIPPI VALLEY.
WINDS SHOULD SHIFT TO NE 5 TO 10KT LATE TONIGHT AROUND 03Z TO 06Z.
//ATL CONFIDENCE...18Z UPDATE...
HIGH ON ALL ELEMENTS.
41
&&
.PRELIMINARY POINT TEMPS/POPS...
ATHENS 67 38 47 41 / 0 0 90 100
ATLANTA 63 43 47 41 / 0 20 100 100
BLAIRSVILLE 57 35 47 38 / 0 0 70 100
CARTERSVILLE 62 37 48 45 / 0 0 90 100
COLUMBUS 68 50 52 47 / 0 60 100 90
GAINESVILLE 64 38 49 38 / 0 0 90 100
MACON 70 44 51 48 / 0 40 100 80
ROME 62 35 49 47 / 0 0 90 100
PEACHTREE CITY 64 35 48 45 / 0 30 100 100
VIDALIA 72 49 58 55 / 20 40 100 60
&&
.FFC WATCHES/WARNINGS/ADVISORIES...
FLOOD WATCH FROM MONDAY MORNING THROUGH TUESDAY EVENING FOR THE
FOLLOWING ZONES: BALDWIN...BANKS...BARROW...BIBB...BLECKLEY...
BUTTS...CARROLL...CHATTAHOOCHEE...CLARKE...CLAYTON...COBB...
COWETA...CRAWFORD...CRISP...DEKALB...DODGE...DOOLY...DOUGLAS...
EMANUEL...FAYETTE...FORSYTH...GLASCOCK...GREENE...GWINNETT...
HALL...HANCOCK...HARRIS...HEARD...HENRY...HOUSTON...JACKSON...
JASPER...JEFFERSON...JOHNSON...JONES...LAMAR...LAURENS...MACON...
MADISON...MARION...MERIWETHER...MONROE...MONTGOMERY...MORGAN...
MUSCOGEE...NEWTON...NORTH FULTON...OCONEE...OGLETHORPE...PEACH...
PIKE...PULASKI...PUTNAM...ROCKDALE...SCHLEY...SOUTH FULTON...
SPALDING...STEWART...SUMTER...TALBOT...TALIAFERRO...TAYLOR...
TELFAIR...TOOMBS...TREUTLEN...TROUP...TWIGGS...UPSON...WALTON...
WARREN...WASHINGTON...WEBSTER...WHEELER...WILCOX...WILKES...
WILKINSON.
&&
$$
SHORT TERM...DEESE
LONG TERM....20
AVIATION...41
AREA FORECAST DISCUSSION
NWS PEACHTREE CITY GA
646 AM EST SUN FEB 24 2013
.PREV DISCUSSION... /ISSUED 349 AM EST SUN FEB 24 2013/
..DENSE FOG ADVISORY IN EFFECT THIS MORNING...
..FLOOD WATCH IN EFFECT FOR PORTIONS OF NORTH AND ALL OF CENTRAL
GEORGIA MONDAY THROUGH TUESDAY...
SHORT TERM /TODAY THROUGH MONDAY NIGHT/...
LATEST REGIONAL RAP ANALYSIS INDICATES FRONTAL BOUNDARY HAS MADE
ITS WAY THROUGH THE FORECAST AREA WITH NW FLOW AT THE SURFACE.
MOISTURE...ESPECIALLY AT THE EXTREME LOW LEVELS HAS BEEN MUCH
SLOWER TO DEPART RESULTING IN DENSE FOG ACROSS THE REGION. HAVE
BEEN TRACKING TWO SEPARATE AREAS OF DENSE FOG...BOTH OF WHICH ARE
TRANSIENT MAKING THE FORECAST CHALLENGING TO SAY THE LEAST AS FAR
AS VISIBILITY IS CONCERNED THROUGH DAYBREAK. HAVE OPTED TO GO WITH
A DENSE FOG ADVISORY FOR THE ENTIRE AREA AND AS CONDITIONS IMPROVE
THROUGH DAYBREAK...CANCEL COUNTIES OUT AS NECESSARY.
TODAY LOOKS TO BE A TRANSITION DAY ACROSS THE AREA...A MUCH NEEDED
BREAK FROM RECENT RAINFALL ACROSS THE SOUTHERN TIER ALTHOUGH
FLOODING WILL BE ONGOING. SOME 5 INCHES OF RAIN IN AREAS FROM
PREVIOUS SYSTEM AND HAVE AREAL FLOOD WARNING IN EFFECT FOR CRISP
COUNTY. WILL SEE FRONT FRONT SETTLE ACROSS NORTH FLORIDA WITH HIGH
PRESSURE BUILDING IN OVER THE OHIO VALLEY AND RIDGING THROUGH
TENNESSEE AND THE LOCAL FORECAST AREA. FLOW ALOFT LOOKS TO REMAIN
ZONAL TO SLIGHTLY RIDGING AND ONCE LOW CLOUDS CLEAR...WE SHOULD
SEE A STELLAR END TO THE WEEKEND WITH TEMPS IN THE 60S AND EVEN A
FEW LOW 70S TO THE SOUTH.
RESPITE FROM THE RAIN LOOKS QUITE SHORT LIVED AS POTENT SHORTWAVE
DIVES INTO THE SOUTHERN PLAINS CREATING A LARGE SCALE DIFFLUENT
FLOW ALOFT FOR THE SOUTHEAST. ADD TO THIS RIPPLES EMBEDDED IN THE
ZONAL FLOW AND SHOULD SEE AREA OF MODERATE RAIN DEVELOP ACROSS THE
SOUTHERN TIER BY MONDAY MORNING. WITH WEDGE STRENGTHENING OVER THE
CAROLINAS...ADIABATIC OMEGA BECOMES MAXIMIZED DURING THE DAY
MONDAY WITH NEAR CATEGORICAL POPS ANTICIPATED AREA WIDE. WILL
DISCUSS FLOOD IMPLICATIONS FURTHER IN HYDROLOGY SECTION.
BY MONDAY NIGHT...WARM FRONT WILL PUSH INTO THE SOUTHERN MOST
COUNTIES WITH LIMITED SURFACE INSTABILITY BUT INCREASED LOW LEVEL
HELICITY. APPEARS AT THIS POINT THAT SEVERE THREAT WILL BE
ISOLATED AT BEST BUT STILL HAVE A FEW ANALOGS WHICH POINT TO
POTENTIAL ISOLATED TORNADO DEVELOPMENT MONDAY NIGHT INTO TUESDAY
MORNING. SREF ADDS SOME VALIDITY TO THIS WITH PROBABILITY OF 50
PERCENT OF STP OF 1 OR GREATER TUESDAY MORNING.
DEESE
LONG TERM /TUESDAY THROUGH SATURDAY/...
GFS AND ECMWF MODELS SIMILAR THROUGH THE EXTENDED FORECAST PERIOD
CONCERNING THE LARGE SCALE PATTERN. RAIN LIFTING OUT OF THE FORECAST
AREA THROUGH THE DAY TUESDAY AS THE MAIN UPPER LOW AND ASSOCIATED
SURFACE LOW LIFT INTO THE EASTERN OHIO VALLEY. UPPER PATTERN THROUGH
THE MAJORITY OF THE REMAINDER OF THE EXTENDED FORECAST PERIOD
DOMINATED BY MODERATE TO STRONG NORTHWESTERLY FLOW AS BROAD BUT DEEP
UPPER TROUGH LINGERS OVER THE EASTERN U.S. TIGHT SURFACE PRESSURE
GRADIENT PERSISTS AS WELL THROUGH THE PERIOD WITH MODERATE TO STRONG
NORTHWESTERLY FLOW PERSISTING. GFS KEEPS LOW QPF ALONG OUR FAR
NORTHERN COUNTIES WEDNESDAY THROUGH SATURDAY WHILE THE ECMWF KEEPS
THE ENTIRE FORECAST AREA DRY THROUGH ALL BUT THURSDAY. HAVE KEPT THE
PREVIOUS TREND OF SLIGHT CHANCE POPS AND VERY LOW QPF FOR THE FAR
NORTH WEDNESDAY THROUGH SATURDAY. MODEL THICKNESSES AND TEMPERATURES
WOULD INDICATE A CHANCE FOR MIXED PRECIPITATION THROUGH THE
PERIOD...ALTHOUGH WITH THE LOW CHANCES AND LIMITED MOISTURE AVAILABLE
ANY AMOUNTS WOULD LIKELY BE VERY SMALL. THIS TREND WILL NEED TO BE
WATCHED CLOSELY AS WE MOVE INTO THE MIDDLE OF THE WEEK. HOWEVER THIS
PATTERN DOES POINT TO A PERIOD OF BELOW NORMAL TEMPERATURES THROUGH
THE EXTENDED FORECAST PERIOD.
20
HYDROLOGY...QPE FROM PREVIOUS EVENT INDICATES 2 INCHES OF RAIN
FELL FROM ROUGHLY THE ATLANTA METRO TO AS MUCH AS 4 INCHES FOR THE
SOUTHERN TIER. SAME AREA IS TARGETED FOR THIS EVENT WITH AN
ADDITIONAL 2 TO 3 INCHES EXPECTED AND HAVE ISSUED A FLOOD WATCH
THROUGH TUESDAY EVENING.
&&
.AVIATION...
12Z UPDATE...
CHALLENGING FORECAST SHOULD EASE AS LOW LEVEL MOISTURE CONTINUES
TO CLEAR. WILL STILL SEE AREAS OF LIFR FOR THE SOUTHERN MOST TAF
SITES BUT GUIDANCE AGREES EVEN THESE SHOULD IMPROVE RAPIDLY TO VFR
BY 14Z. VFR FOR THE REMAINDER OF THE PERIOD BUT WILL NEED TO ADD A
PROB30 FOR DEVELOPMENT OF -RA MONDAY MORNING. LOOKING FOR A
WINDSHIFT OVERNIGHT AS WELL WITH GOOD AGREEMENT AT A SWITCHOVER TO
EAST AFTER 06Z.
//ATL CONFIDENCE...12Z UPDATE...
HIGH ON ALL ELEMENTS.
DEESE
&&
.PRELIMINARY POINT TEMPS/POPS...
ATHENS 67 38 47 41 / 0 0 90 100
ATLANTA 63 43 47 41 / 0 20 100 100
BLAIRSVILLE 57 35 47 38 / 0 0 70 100
CARTERSVILLE 62 37 48 45 / 0 0 90 100
COLUMBUS 68 50 52 47 / 0 60 100 90
GAINESVILLE 64 38 49 38 / 0 0 90 100
MACON 70 44 51 48 / 0 40 100 80
ROME 62 35 49 47 / 0 0 90 100
PEACHTREE CITY 64 35 48 45 / 0 30 100 100
VIDALIA 72 49 58 55 / 20 40 100 60
&&
.FFC WATCHES/WARNINGS/ADVISORIES...
FLOOD WATCH FROM MONDAY MORNING THROUGH TUESDAY EVENING FOR THE
FOLLOWING ZONES: BALDWIN...BANKS...BARROW...BIBB...BLECKLEY...
BUTTS...CARROLL...CHATTAHOOCHEE...CLARKE...CLAYTON...COBB...
COWETA...CRAWFORD...CRISP...DEKALB...DODGE...DOOLY...DOUGLAS...
EMANUEL...FAYETTE...FORSYTH...GLASCOCK...GREENE...GWINNETT...
HALL...HANCOCK...HARRIS...HEARD...HENRY...HOUSTON...JACKSON...
JASPER...JEFFERSON...JOHNSON...JONES...LAMAR...LAURENS...MACON...
MADISON...MARION...MERIWETHER...MONROE...MONTGOMERY...MORGAN...
MUSCOGEE...NEWTON...NORTH FULTON...OCONEE...OGLETHORPE...PEACH...
PIKE...PULASKI...PUTNAM...ROCKDALE...SCHLEY...SOUTH FULTON...
SPALDING...STEWART...SUMTER...TALBOT...TALIAFERRO...TAYLOR...
TELFAIR...TOOMBS...TREUTLEN...TROUP...TWIGGS...UPSON...WALTON...
WARREN...WASHINGTON...WEBSTER...WHEELER...WILCOX...WILKES...
WILKINSON.
DENSE FOG ADVISORY UNTIL 9 AM EST THIS MORNING FOR THE FOLLOWING
ZONES: BALDWIN...BANKS...BARROW...BARTOW...BIBB...BLECKLEY...
BUTTS...CARROLL...CATOOSA...CHATTAHOOCHEE...CHATTOOGA...
CHEROKEE...CLARKE...CLAYTON...COBB...COWETA...CRAWFORD...CRISP...
DADE...DAWSON...DEKALB...DODGE...DOOLY...DOUGLAS...EMANUEL...
FANNIN...FAYETTE...FLOYD...FORSYTH...GILMER...GLASCOCK...
GORDON...GREENE...GWINNETT...HALL...HANCOCK...HARALSON...
HARRIS...HEARD...HENRY...HOUSTON...JACKSON...JASPER...
JEFFERSON...JOHNSON...JONES...LAMAR...LAURENS...LUMPKIN...
MACON...MADISON...MARION...MERIWETHER...MONROE...MONTGOMERY...
MORGAN...MURRAY...MUSCOGEE...NEWTON...NORTH FULTON...OCONEE...
OGLETHORPE...PAULDING...PEACH...PICKENS...PIKE...POLK...
PULASKI...PUTNAM...ROCKDALE...SCHLEY...SOUTH FULTON...SPALDING...
STEWART...SUMTER...TALBOT...TALIAFERRO...TAYLOR...TELFAIR...
TOOMBS...TOWNS...TREUTLEN...TROUP...TWIGGS...UNION...UPSON...
WALKER...WALTON...WARREN...WASHINGTON...WEBSTER...WHEELER...
WHITE...WHITFIELD...WILCOX...WILKES...WILKINSON.
&&
$$
SHORT TERM...DEESE
LONG TERM....20
AVIATION...DEESE
AREA FORECAST DISCUSSION
NWS PEACHTREE CITY GA
349 AM EST SUN FEB 24 2013
...DENSE FOG ADVISORY IN EFFECT THIS MORNING...
...FLOOD WATCH IN EFFECT FOR PORTIONS OF NORTH AND ALL OF CENTRAL
GEORGIA MONDAY THROUGH TUESDAY...
.SHORT TERM /TODAY THROUGH MONDAY NIGHT/...
LATEST REGIONAL RAP ANALYSIS INDICATES FRONTAL BOUNDARY HAS MADE
ITS WAY THROUGH THE FORECAST AREA WITH NW FLOW AT THE SURFACE.
MOISTURE...ESPECIALLY AT THE EXTREME LOW LEVELS HAS BEEN MUCH
SLOWER TO DEPART RESULTING IN DENSE FOG ACROSS THE REGION. HAVE
BEEN TRACKING TWO SEPARATE AREAS OF DENSE FOG...BOTH OF WHICH ARE
TRANSIENT MAKING THE FORECAST CHALLENGING TO SAY THE LEAST AS FAR
AS VISIBILITY IS CONCERNED THROUGH DAYBREAK. HAVE OPTED TO GO WITH
A DENSE FOG ADVISORY FOR THE ENTIRE AREA AND AS CONDITIONS IMPROVE
THROUGH DAYBREAK...CANCEL COUNTIES OUT AS NECESSARY.
TODAY LOOKS TO BE A TRANSITION DAY ACROSS THE AREA...A MUCH NEEDED
BREAK FROM RECENT RAINFALL ACROSS THE SOUTHERN TIER ALTHOUGH
FLOODING WILL BE ONGOING. SOME 5 INCHES OF RAIN IN AREAS FROM
PREVIOUS SYSTEM AND HAVE AREAL FLOOD WARNING IN EFFECT FOR CRISP
COUNTY. WILL SEE FRONT FRONT SETTLE ACROSS NORTH FLORIDA WITH HIGH
PRESSURE BUILDING IN OVER THE OHIO VALLEY AND RIDGING THROUGH
TENNESSEE AND THE LOCAL FORECAST AREA. FLOW ALOFT LOOKS TO REMAIN
ZONAL TO SLIGHTLY RIDGING AND ONCE LOW CLOUDS CLEAR...WE SHOULD
SEE A STELLAR END TO THE WEEKEND WITH TEMPS IN THE 60S AND EVEN A
FEW LOW 70S TO THE SOUTH.
RESPITE FROM THE RAIN LOOKS QUITE SHORT LIVED AS POTENT SHORTWAVE
DIVES INTO THE SOUTHERN PLAINS CREATING A LARGE SCALE DIFFLUENT
FLOW ALOFT FOR THE SOUTHEAST. ADD TO THIS RIPPLES EMBEDDED IN THE
ZONAL FLOW AND SHOULD SEE AREA OF MODERATE RAIN DEVELOP ACROSS THE
SOUTHERN TIER BY MONDAY MORNING. WITH WEDGE STRENGTHENING OVER THE
CAROLINAS...ADIABATIC OMEGA BECOMES MAXIMIZED DURING THE DAY
MONDAY WITH NEAR CATEGORICAL POPS ANTICIPATED AREA WIDE. WILL
DISCUSS FLOOD IMPLICATIONS FURTHER IN HYDROLOGY SECTION.
BY MONDAY NIGHT...WARM FRONT WILL PUSH INTO THE SOUTHERN MOST
COUNTIES WITH LIMITED SURFACE INSTABILITY BUT INCREASED LOW LEVEL
HELICITY. APPEARS AT THIS POINT THAT SEVERE THREAT WILL BE
ISOLATED AT BEST BUT STILL HAVE A FEW ANALOGS WHICH POINT TO
POTENTIAL ISOLATED TORNADO DEVELOPMENT MONDAY NIGHT INTO TUESDAY
MORNING. SREF ADDS SOME VALIDITY TO THIS WITH PROBABILITY OF 50
PERCENT OF STP OF 1 OR GREATER TUESDAY MORNING.
DEESE
.LONG TERM /TUESDAY THROUGH SATURDAY/...
GFS AND ECMWF MODELS SIMILAR THROUGH THE EXTENDED FORECAST PERIOD
CONCERNING THE LARGE SCALE PATTERN. RAIN LIFTING OUT OF THE FORECAST
AREA THROUGH THE DAY TUESDAY AS THE MAIN UPPER LOW AND ASSOCIATED
SURFACE LOW LIFT INTO THE EASTERN OHIO VALLEY. UPPER PATTERN THROUGH
THE MAJORITY OF THE REMAINDER OF THE EXTENDED FORECAST PERIOD
DOMINATED BY MODERATE TO STRONG NORTHWESTERLY FLOW AS BROAD BUT DEEP
UPPER TROUGH LINGERS OVER THE EASTERN U.S. TIGHT SURFACE PRESSURE
GRADIENT PERSISTS AS WELL THROUGH THE PERIOD WITH MODERATE TO STRONG
NORTHWESTERLY FLOW PERSISTING. GFS KEEPS LOW QPF ALONG OUR FAR
NORTHERN COUNTIES WEDNESDAY THROUGH SATURDAY WHILE THE ECMWF KEEPS
THE ENTIRE FORECAST AREA DRY THROUGH ALL BUT THURSDAY. HAVE KEPT THE
PREVIOUS TREND OF SLIGHT CHANCE POPS AND VERY LOW QPF FOR THE FAR
NORTH WEDNESDAY THROUGH SATURDAY. MODEL THICKNESSES AND TEMPERATURES
WOULD INDICATE A CHANCE FOR MIXED PRECIPITATION THROUGH THE
PERIOD...ALTHOUGH WITH THE LOW CHANCES AND LIMITED MOISTURE AVAILABLE
ANY AMOUNTS WOULD LIKELY BE VERY SMALL. THIS TREND WILL NEED TO BE
WATCHED CLOSELY AS WE MOVE INTO THE MIDDLE OF THE WEEK. HOWEVER THIS
PATTERN DOES POINT TO A PERIOD OF BELOW NORMAL TEMPERATURES THROUGH
THE EXTENDED FORECAST PERIOD.
20
&&
.HYDROLOGY...QPE FROM PREVIOUS EVENT INDICATES 2 INCHES OF RAIN
FELL FROM ROUGHLY THE ATLANTA METRO TO AS MUCH AS 4 INCHES FOR THE
SOUTHERN TIER. SAME AREA IS TARGETED FOR THIS EVENT WITH AN
ADDITIONAL 2 TO 3 INCHES EXPECTED AND HAVE ISSUED A FLOOD WATCH
THROUGH TUESDAY EVENING.
&&
AVIATION...
06Z UPDATE...
CHALLENGING FORECAST IN STORE AS LOW LEVEL MOISTURE CLEARS BUT
RESIDUAL MOISTURE FROM RECENT RAINS REMAINS AT THE SURFACE. THIS
SHOULD RESULT IN LOW CLOUDS CLEARING BUT THE POTENTIAL FOR FOG
DEVELOPMENT. ATL STILL AT 5 TO 7 KTS WITH VSBY REMAINING MVFR TO
VFR BUT MUCH LESS VISIBILITY VALUES NOTED TO THE NORTH. FEEL WE
WILL GET REDUCTIONS AT ALL SITES FOR THE FIRST HALF OF THE
OVERNIGHT PERIOD...ESPECIALLY AT SOUTHERN SITES AND AHN BUT MAY
SEE PARTIAL IMPROVEMENT TOWARD DAYBREAK BUT CONFIDENCE IS LOW.
//ATL CONFIDENCE...06Z UPDATE...
LOW ON FOG DEVELOPMENT.
HIGH ON REMAINING ELEMENTS.
DEESE
&&
.PRELIMINARY POINT TEMPS/POPS...
ATHENS 67 38 47 41 / 0 0 90 100
ATLANTA 63 43 47 41 / 0 20 100 100
BLAIRSVILLE 57 35 47 38 / 0 0 70 100
CARTERSVILLE 62 37 48 45 / 0 0 90 100
COLUMBUS 68 50 52 47 / 0 60 100 90
GAINESVILLE 64 38 49 38 / 0 0 90 100
MACON 70 44 51 48 / 0 40 100 80
ROME 62 35 49 47 / 0 0 90 100
PEACHTREE CITY 64 35 48 45 / 0 30 100 100
VIDALIA 72 49 58 55 / 20 40 100 60
&&
.FFC WATCHES/WARNINGS/ADVISORIES...
FLOOD WATCH FROM MONDAY MORNING THROUGH TUESDAY EVENING FOR THE
FOLLOWING ZONES: BALDWIN...BANKS...BARROW...BIBB...BLECKLEY...
BUTTS...CARROLL...CHATTAHOOCHEE...CLARKE...CLAYTON...COBB...
COWETA...CRAWFORD...CRISP...DEKALB...DODGE...DOOLY...DOUGLAS...
EMANUEL...FAYETTE...FORSYTH...GLASCOCK...GREENE...GWINNETT...
HALL...HANCOCK...HARRIS...HEARD...HENRY...HOUSTON...JACKSON...
JASPER...JEFFERSON...JOHNSON...JONES...LAMAR...LAURENS...MACON...
MADISON...MARION...MERIWETHER...MONROE...MONTGOMERY...MORGAN...
MUSCOGEE...NEWTON...NORTH FULTON...OCONEE...OGLETHORPE...PEACH...
PIKE...PULASKI...PUTNAM...ROCKDALE...SCHLEY...SOUTH FULTON...
SPALDING...STEWART...SUMTER...TALBOT...TALIAFERRO...TAYLOR...
TELFAIR...TOOMBS...TREUTLEN...TROUP...TWIGGS...UPSON...WALTON...
WARREN...WASHINGTON...WEBSTER...WHEELER...WILCOX...WILKES...
WILKINSON.
DENSE FOG ADVISORY UNTIL 9 AM EST THIS MORNING FOR THE FOLLOWING
ZONES: BALDWIN...BANKS...BARROW...BARTOW...BIBB...BLECKLEY...
BUTTS...CARROLL...CATOOSA...CHATTAHOOCHEE...CHATTOOGA...
CHEROKEE...CLARKE...CLAYTON...COBB...COWETA...CRAWFORD...CRISP...
DADE...DAWSON...DEKALB...DODGE...DOOLY...DOUGLAS...EMANUEL...
FANNIN...FAYETTE...FLOYD...FORSYTH...GILMER...GLASCOCK...
GORDON...GREENE...GWINNETT...HALL...HANCOCK...HARALSON...
HARRIS...HEARD...HENRY...HOUSTON...JACKSON...JASPER...
JEFFERSON...JOHNSON...JONES...LAMAR...LAURENS...LUMPKIN...
MACON...MADISON...MARION...MERIWETHER...MONROE...MONTGOMERY...
MORGAN...MURRAY...MUSCOGEE...NEWTON...NORTH FULTON...OCONEE...
OGLETHORPE...PAULDING...PEACH...PICKENS...PIKE...POLK...
PULASKI...PUTNAM...ROCKDALE...SCHLEY...SOUTH FULTON...SPALDING...
STEWART...SUMTER...TALBOT...TALIAFERRO...TAYLOR...TELFAIR...
TOOMBS...TOWNS...TREUTLEN...TROUP...TWIGGS...UNION...UPSON...
WALKER...WALTON...WARREN...WASHINGTON...WEBSTER...WHEELER...
WHITE...WHITFIELD...WILCOX...WILKES...WILKINSON.
&&
$$
SHORT TERM...DEESE
LONG TERM....20
AVIATION...DEESE
AREA FORECAST DISCUSSION
NWS DES MOINES IA
924 PM CST MON FEB 25 2013
.UPDATE...
NO CHANGES TO HEADLINES OR FORECAST THIS EVENING. 18Z GUIDANCE HAD
A POOR HANDLE ON SITUATION WITH MO/AR CONVECTION STRONGER AND
FARTHER EAST THAN ANTICIPATED. THIS LIKELY RESULTING IN MODELS
INCORRECTLY HANDLING THE LATENT HEAT/PV BUDGETS WITH QUESTIONABLE
RESULTS. 18Z NAM WAS DEFINITELY ONE OF THOSE LACKING AND THE 00Z
RUN SEEMS BEHIND BRINGING TROWEL PRECIP INTO KC METRO AREA RIGHT
NOW. SO WITH LITTLE NEW TRUSTED GUIDANCE AVAILABLE...WILL LEAVE
CURRENT FORECAST AND HEADLINES RIDE. SHORTER TERM 00Z HRRR DOES
SEEM TO HAVE A GRASP ON REALITY AND BRINGS PRECIP INTO SRN IA
OVERNIGHT...ANOTHER REASON TO LEAVE THINGS AS IS.
&&
.SHORT TERM /TONIGHT/...
LOW PRESSURE NOW DEEPENING OVER ARKANSAS THIS AFTERNOON. THE
SYSTEM WILL LIFT VERY SLOWLY NORTHEAST OVERNIGHT AND WILL BEGIN
TO INCH INTO FAR SOUTHERN MISSOURI BY 12Z. THE UPPER LEVEL LOW IS
BACK TO THE WEST OVER OKLAHOMA AND TEXAS AND WILL BECOME NEARLY
STACKED WITH THE SFC FEATURE BY 12Z. THE PRESSURE GRADIENT WILL
INCREASE OVER IOWA OVERNIGHT AND WILL INCREASE NORTHERN SURFACE
WINDS ACROSS THE STATE. THE SOURCE REGION FOR THESE WINDS WILL BE
FROM HIGH PRESSURE OVER MINNESOTA AND WISCONSIN WHICH WILL
CONTINUE TO FUNNEL DRIER AIR INTO THE STATE. AS THIS OCCURS...MID
LEVEL THETA-E ADVECTION WILL LIFT NORTH INTO SOUTHERN IOWA. THE
INFILTRATION OF THE DRIER AIR WILL DELAY THE ONSET OF SNOW ACROSS
THAT REGION. THERE IS SOME POTENTIAL FOR SATURATION TO OCCUR OVER
FAR SOUTH CENTRAL TO SOUTHWEST IOWA TO SATURATE TOWARD 06Z.
POTENTIAL FOR UP TO ONE INCH OF SNOW IN THESE AREAS. ELSEWHERE
WILL REMAIN DRY THROUGH THE PERIOD.
AREAS OF FOG LINGERED ACROSS NORTHWEST IOWA THROUGH THE DAY.
POSSIBLE THAT VISIBILITIES WILL LOWER A BIT OVERNIGHT THROUGH
EXPECT THE INCREASING NORTHERLY FLOW OVERNIGHT WILL IMPROVE
CONDITIONS THROUGH THE PERIOD.
.LONG TERM /TUESDAY THROUGH SUNDAY/...
MAIN FORECAST CONCERN IS WITH UPPER LOW STRENGTHENING AS IT MOVES
ACROSS THE CENTRAL/SOUTHERN PLAINS TONIGHT THROUGH WEDNESDAY. MODELS
HAVE TRENDED ON A FURTHER SOUTHEAST TRACK AS SURFACE HIGH REMAINS A
STRONGHOLD OVER THE WESTERN GREAT LAKES DURING THE DAY TUESDAY.
LEANED TOWARD A SREF/GFS BLEND AND THE 12Z ECMWF AS THESE MODELS ARE
IN GOOD AGREEMENT WITH ONE ANOTHER. NAM HAS COMPLETELY SHIFTED THE
LOW TRACK FURTHER SOUTHEAST COMPARED TO PREVIOUS RUNS AND HAD LOW
CONFIDENCE WITH THIS SOLUTIONS DUE TO DISCONTINUITY.
TUESDAY THROUGH WEDNESDAY...NEAR VERTICALLY STACKED LOW WILL TRACK
ACROSS THE OZARKS INTO OHIO VALLEY THROUGHOUT THE DAY TUESDAY AND
TUESDAY NIGHT. A SECONDARY SHORTWAVE QUICKLY MOVES ACROSS NORTHERN
MISSOURI TUESDAY NIGHT INTO WEDNESDAY. BEST FRONTOGENETICAL FORCING
REMAINS JUST ALONG THE IOWA/MISSOURI BY 12Z TO 18Z TUESDAY...THEN
LOOKS TO BE AN ELONGATED PERIOD OF LIGHT TO MODERATE SNOW. MAX OMEGA
WITHIN THE DENDRITIC ZONE MATCHES UP WELL LATE TUESDAY MORNING INTO
THE EARLY AFTERNOON HOURS ACROSS FAR SOUTHEAST IOWA...THEN WEAKENS
BY THE AFTERNOON AND EVENING. SECOND SHORTWAVE WILL BRING
REINFORCEMENT OF LIFT AND MOISTURE AND LOOKS TO PROLONG THE SNOWFALL
INTO EARLY WEDNESDAY. OTHER CONCERN IS WITH STRONG SURFACE WINDS AS
PRESSURE GRADIENT REALLY TIGHTENS THROUGHOUT THE DAY TOMORROW AND
CONTINUES INTO WEDNESDAY MORNING. WINDS AT 925MB ARE ROUGHLY 35KTS
THROUGH MUCH OF THE DAY TUESDAY THEN DECREASING SOMEWHAT TOMORROW
NIGHT INTO WEDNESDAY. SHARP GRADIENT WRT TO SNOW AMOUNTS SETS UP
ACROSS SOUTHEAST IOWA WITH THE DRY AIR ADVECTING IN FROM THE NORTH.
CONFIDENT THOUGH THE SOUTHEAST WILL SEE A 4 TO 6 INCH RANGE
COMBINED WITH THE STRONG WINDS...LEANED TOWARD WINTER STORM
WARNING.
THURSDAY THROUGH SUNDAY...NO MAJOR CHANGES WITH EXTENDED PERIOD AS
HIGH PRESSURE REMAINS IN CONTROL THROUGH THE WEEKEND. A GRADUAL
WARM UP BEGINS BY THE WEEKEND INTO EARLY NEXT WEEK.
&&
.AVIATION...26/00Z
MAIN CONCERN INTO TONIGHT AND TUE WILL BE ONSET OF PRECIP AND EXTENT
OF VSBY/CIG RESTRICTIONS. UNFORTUNATELY THERE IS LOW CONFIDENCE
WITH SOME MODELS NOT HANDLING REALITY WELL...AND NOT GREAT CONSENSUS
LOOKING AHEAD EITHER. TAKING A BLEND OF DRIEST AND MOST AGGRESSIVE
NORTHWARD SOLUTIONS...BOTH SEEMINGLY INCORRECT...WOULD SUGGEST
KDSM/KOTM WILL BEGIN TO SEE AT LEAST MVFR CONDITIONS THROUGH MUCH OF
THE DAY TUE...ESPECIALLY KOTM. LOWER CATEGORIES ARE
POSSIBLE...MAINLY KOTM...BUT CONFIDENCE IN THAT OCCURRING IS NOT
SUFFICIENT TO INCLUDE RIGHT NOW.
&&
.DMX WATCHES/WARNINGS/ADVISORIES...
WINTER WEATHER ADVISORY FROM 9 AM TUE TO 6 AM WED
CLARKE-DECATUR-LUCAS-MAHASKA-MARION-MONROE-RINGGOLD-WAPELLO-WAYNE
WINTER STORM WARNING FROM 9 AM TUE TO 6 AM CST WED APPANOOSE-DAVIS
&&
$$
UPDATE/AVIATION...SMALL
SHORT TERM...DONAVON
LONG TERM...PODRAZIK
AREA FORECAST DISCUSSION
NWS DODGE CITY KS
1159 AM CST SUN FEB 24 2013
...UPDATED FOR AVIATION...
.SYNOPSIS...
ISSUED AT 352 AM CST SUN FEB 24 2013
THE 00Z UPPER AIR ANALYSIS SHOWED A MID/UPPER LEVEL TROUGH OVER THE
GREAT BASIN. THIS TROUGH CONTINUES TO DEEPEN AS IT MOVES SOUTHEAST
AND SHOULD CONTINUE TO DO SO GIVEN A 130 KNOT UPPER LEVEL JET ON THE
BACK SIDE OF THE UPPER TROUGH AND 130 METER HEIGHT FALLS TO ITS
SOUTHEAST. AT THE SURFACE, LOW PRESSURE WAS DEEPENING OVER NORTHEAST
NEW MEXICO. EAST OF THE LOW, UPPER 20S TO LOW 30S DEWPOINTS WERE
SPREADING NORTHWARD TOWARD THE CENTRAL HIGH PLAINS. AREAS OF FOG AND
LOW STRATUS WERE OCCURRING OVER WEST CENTRAL AND NORTHWEST KANSAS
EARLY THIS MORNING WITH SOME INDICATIONS OF DEVELOPMENT INTO
SOUTHWEST KANSAS.
&&
.SHORT TERM...(TODAY THROUGH TONIGHT)
ISSUED AT 352 AM CST SUN FEB 24 2013
VISIBILITIES ACROSS SOUTHWEST KANSAS HAVE BEEN STAYING MOSTLY IN THE
MVFR CATEGORY THROUGH THE EARLY MORNING HOURS WITH THE FAR NORTHERN
LOCATIONS AROUND HAYS SEEING VISIBILITIES OCCASIONALLY DROPPING TO A
QUARTER TO HALF MILE IN FOG. THE RUC13 AND HRRR ARE PICKING UP ON
THE FOG AND ARE SHOWING SOME SIGNIFICANT DEVELOPMENT TO THE SOUTH
ACROSS MUCH OF WEST CENTRAL AND SOUTHWEST KANSAS THROUGH THE NEXT
FEW HOURS THROUGH SUNRISE. THE 11-3.9U FOG CHANNEL HAS BEEN SHOWING
SOME HINTS OF FOG/STRATUS DEVELOPMENT AROUND COLDWATER/MEDICINE
LODGE AND GREENSBURG OVER THE PAST HOUR SO IT APPEARS THAT THERE IS
STILL POTENTIAL FOR THE FOG TO DEVELOP. HAVE LEFT THE DENSE FOG
ADVISORY IN PLACE THROUGH 9AM. IF NOTHING HAPPENS BY SUNRISE THEN
THE ADVISORY MAY BE ADJUSTED OR CANCELLED SOONER.
CONDITIONS ARE CONTINUING TO COME TOGETHER FOR A SIGNIFICANT WINTER
WEATHER EVENT ACROSS PARTS OF THE CENTRAL HIGH PLAINS STARTING THIS
EVENING AND CONTINUING THROUGH MONDAY EVENING. THE 00Z RUNS OF THE
NAM/GFS AND ECMWF ALL SHOW AN UPPER LOW CLOSING OFF OVER NEW MEXICO
BY THIS EVENING AND THEN INTENSIFYING AS IT TRACKS EAST INTO THE RED
RIVER VALLEY ON MONDAY. THE MODELS ARE ALL SHOWING PRECIPITATION
DEVELOPING ACROSS SOUTHWEST KANSAS LATE THIS AFTERNOON AND TONIGHT.
INITIAL PRECIPITATION COULD BE IN THE FORM OF FREEZING DRIZZLE OVER
FAR WESTERN KANSAS BUT THINK THIS WILL BE SHORT LIVED AS THE MID
LEVELS MOISTEN UP AND THE RESULTANT SEEDER/FEEDER MECHANISM CHANGES
PRECIPITATION OVER TO SNOW. FAR SOUTH CENTRAL KANSAS MAY SEE A
RAIN/SNOW MIX FOR A TIME TONIGHT AS TEMPERATURES IN THE LOWER LEVELS
HOVER AT OR SLIGHTLY ABOVE ZERO. AT ANY RATE, SNOW SHOULD BE
DEVELOPING OVER ALL OF SOUTHWEST AND CENTRAL KANSAS AS THE NIGHT
GOES ON AND BECOME HEAVY AT TIMES. SNOWFALL ACCUMULATIONS COULD BE
AS MUCH AS TWO TO FIVE INCHES BY MONDAY MORNING. WITH NORTH WINDS
EXPECTED TO INCREASE TO AROUND 25 TO 35 MPH, THERE WILL BE
CONSIDERABLE BLOWING AND DRIFTING SNOW WITH WIDESPREAD VISIBILITIES
AT A QUARTER MILE OR LESS EXPECTED. WITH THIS IN MIND, HAVE UPGRADED
THE BLIZZARD WATCH TO A BLIZZARD WARNING FOR ALL OF SOUTHWEST INTO
WEST CENTRAL AND SOUTH CENTRAL KANSAS TONIGHT.
.LONG TERM...(MONDAY THROUGH SATURDAY)
ISSUED AT 400 AM CST SUN FEB 24 2013
BLIZZARD CONDITIONS WILL CONTINUE MONDAY. VERY DANGEROUS TRAVEL CONDITIONS
ARE EXPECTED ACROSS THE REGION WITH HEAVY MESOSCALE SNOW BANDS DEVELOPING
IN THE 700 HPA DEFORMATION AXIS IN COMBINATION WITH 30 KT SURFACE WINDS.
THE 00Z GUIDANCE STILL SUPPORTS THE ONGOING FORECAST WITH HEAVY SNOW
ACROSS KANSAS. THE NAM SUGGESTS AS HIGH AS 60 KT 850 HPA WINDS, WHICH
WOULD MEAN SUSTAINED WINDS POSSIBLY AS HIGH AS 35-40 KT AT THE SURFACE.
THE ECMWF IS WEAKER WITH THE WIND PROFILE. TRAVEL IS NOT RECOMMENDED
MONDAY...IT WILL BE VERY UNSAFE TRAVEL CONDITIONS WITH WHITEOUT CONDITIONS
AND VERY LARGE SNOWDRIFTS. FOR MORE SPECIFIC INFORMATION REGARDING THE
BLIZZARD, PLEASE SEE THE WARNING TEXT /WSWDDC/. CONDITIONS WILL TAPER
WEST TO EAST THROUGH TUESDAY MORNING AS THE CYCLONE MOVES SOUTHEAST
OF THE REGION.
THE REST OF THE FORECAST WAS LEFT AS IS FROM THE ALLBLEND SOLUTION DUE
TO TIME CONSTRAINTS. HIGHS WILL MODERATE INTO THE 30S AND 40S BY MIDWEEK,
ALTHOUGH THE ALLBLEND NUMBERS COULD BE ON THE HIGH SIDE IF THE HEAVY
SNOWPACK DOES COME INTO FRUITION. LOWS WILL BE IN THE TEENS AND 20S.
AGAIN, THESE VALUES COULD BE ON THE HIGH SIDE IF WE GET SIGNIFICANT
ADDITIONAL SNOWS. THE REST OF THE FORECAST LOOKS DRY AS UPPER LEVEL
RIDGING DEVELOPS OUT WEST AND A DRY NORTHERLY FLOW PATTERN PREVAILS
ACROSS WESTERN KANSAS.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z MONDAY AFTERNOON)
ISSUED AT 1158 AM CST SUN FEB 24 2013
RAPIDLY DETERIORATING CEILINGS AND VISIBILITY WITH TIME IS EXPECTED
DURING THIS TAF PERIOD. AS SURFACE PRESSURE FALLS ACROSS FAR
SOUTHEAST COLORADO CONTINUES, LIFR/VLIFR STRATUS CLOUDS WILL FILL IN
FROM NORTHWEST TO SOUTHEAST ACROSS WESTERN KANSAS TERMINALS SITES.
SNOW WILL DEVELOP OVER THE PANHANDLES AND SPREAD RAPIDLY NORTHWARD
ACROSS THE AREA BETWEEN 00 UTC AND 03 UTC. CONDITIONS WILL
DETERIORATE WITH RESPECT TO BLSN AND M1/4SM VISIBILITIES DURING THE
OVERNIGHT BASED ON EXCELLENT MODEL AGREEMENT.
&&
.PRELIMINARY POINT TEMPS/POPS...
DDC 32 24 32 18 / 40 100 100 60
GCK 32 22 33 13 / 40 90 100 40
EHA 32 18 33 16 / 40 90 100 30
LBL 33 21 33 14 / 30 100 100 40
HYS 30 24 31 21 / 40 100 100 60
P28 34 28 32 25 / 30 100 100 80
&&
.DDC WATCHES/WARNINGS/ADVISORIES...
BLIZZARD WARNING FROM 6 PM CST /5 PM MST/ THIS EVENING TO
MIDNIGHT CST /11 PM MST/ MONDAY NIGHT FOR KSZ030-031-043>046-
061>066-074>081-084>090.
&&
$$
SYNOPSIS...GERARD
SHORT TERM...GERARD
LONG TERM...SUGDEN
AVIATION...RUSSELL
AREA FORECAST DISCUSSION
NWS GOODLAND KS
1035 AM MST SUN FEB 24 2013
.UPDATE...
ISSUED AT 935 AM MST SUN FEB 24 2013
MADE A QUICK UPDATE TO FORECAST TO CONTINUE DENSE FOG/VERY LIGHT
FREEZING DRIZZLE THROUGH MUCH OF THE DAY AS VISIBILITIES REMAIN LOW
IN FOG ACROSS ALL BUT THE NORTHWEST SECTION OF CWA. ALSO MODIFIED
WX/SNOW GRIDS TO REFLECT CURRENT PRECIPITATION SHIELD WITH SNOW
BEGINNING TO ACCUMULATE AROUND YUMA CO. LATEST RUC HAS A VERY GOOD
HANDLE ON THE PRECIPITATION AND USED IT AS BASELINE FOR FORECAST
OVER NEXT 3-4 HOURS. WHILE THERE DOES APPEAR TO BE A POCKET OF
WEAKER STABILITY IN THE NORTHWEST...DOES NOT APPEAR TO BE
CO LOCATED WITH STRONGER MESOSCALE FORCING AND WILL KEEP AMOUNTS IN
THE 1 TO 3 IN RANGE FOR THE AFTERNOON. STILL ASSESSING NEWEST
GUIDANCE WITH RESPECT TO HOW SYSTEM DEVELOPS TOMORROW.
&&
.SHORT TERM...(TODAY THROUGH TUESDAY NIGHT)
ISSUED AT 416 AM MST SUN FEB 24 2013
MAIN FORECAST CONCERN WILL WINTER STORM THAT WILL AFFECT THE AREA
THROUGH MOST OF THE SHORT TERM. SATELLITE SHOWING A PROGRESSIVE FLOW
OVER THE PACIFIC. THIS TRANSITIONS TO A MORE AMPLIFIED AND SPLIT
FLOW OVER NORTH AMERICA. MAIN FEATURE OF INTEREST IS SYSTEM
DEVELOPING NEAR THE FOUR CORNERS.
AT JET LEVEL...THE ECMWF WAS DOING SLIGHTLY BETTER THAN THE REST OF
THE MODELS. AT MID LEVELS...SATELLITE AND UPPER AIR ANALYSIS WOULD
INDICATE THAT THE UKMET AND GFS HAVE THE BEST HANDLE ON INCOMING
STORM SYSTEM THROUGH. THE HIGH RESOLUTION NAM/RUC FOLLOWED BY THE
ECMWF GO THE SURFACE WIND/PRESSURE FIELD THE BEST. THE GFS AND NAM
WERE DOING SLIGHTLY BETTER ON THE LOW LEVEL THERMAL FIELD.
TODAY/TONIGHT...DRY MID LEVEL AIR IS BEING DRAWN UP AHEAD OF THE
UPPER SYSTEM. THIS IS ON TOP OF A RATHER MOIST LOW LEVELS PER
CURRENT OBSERVATIONS WITH STRATUS/FOG. MODELS SHOW THAT THE LEFT
FRONT QUADRANT IS AFFECT THE AREA AT 12Z. THIS MOVES SLOWLY SOUTH AND
EAST AND BY LATE AFTERNOON/EARLY EVENING IT IS SOUTH OF THE AREA.
COMPLEX UPPER LOW MOVES INTO THE AREA TODAY AND THEN SPLITS AND/OR
REDEVELOPS FURTHER SOUTH BEGINNING LATER TODAY INTO TONIGHT. MOST
NEW MODEL RUNS ARE FURTHER SOUTH WITH THIS LOW THAN YESTERDAY WITH
THE ENSEMBLES SHOWING THAT SAME TREND AS WELL. IN ADDITION TO BE
FURTHER SOUTH THE MODELS SHOWING THIS REDEVELOPMENT FURTHER WEST AS
WELL. MODELS ARE FURTHER WEST/SLOWER THAN YESTERDAY. ALL THESE TRENDS
MAKES SENSE WITH THE STRONGEST JET WINDS ON THE BACKSIDE OF THE
TROUGH WITH STILL LARGE HEIGHT FALLS AT THE BASE/BEHIND THE TROUGH.
SATELLITE SHOWING/CONFIRMING THIS NICELY.
VERY COMPLEX AND LOW CONFIDENCE FORECAST WITH A NUMBER OF ISSUES TO
ADDRESS. INITIALLY WILL HAVE DENSE FOG COVERING MOST OF THE AREA
THROUGH THE MORNING WITH THE MODELS STILL HAVING A HARD TIME WITH
THIS BUT THE HRRR SEEMS TO HAVE CAUGHT ONTO IT. BECAUSE OF THE
DRIER IN PLACE ABOVE THE SATURATED LOW LAYERS AND THE BETTER LIFT
FURTHER SOUTH AND WEST THAN BEFORE...ALSO NOT ALIGNING WELL WITH
EACH OTHER...AM NOT VERY OPTIMISTIC ABOUT VERY MUCH SNOW OCCURRING.
KEPT THE PATCHY FREEZING DRIZZLE IN THROUGH THE DAY. SNOW SHOULD
DEVELOP IN THE WEST ON THE BACKSIDE OF THE WEAKENING NORTHERN
PORTION OF THIS LOW. BY THE TIME THE SYSTEM GETS ITS ACT TOGETHER
IT IS TOO FAR SOUTH TO GIVE THE AREA A SIGNIFICANT AMOUNT OF SNOW.
SO ENDED UP CUTTING AMOUNTS. NEXT COMES THE WINDS WITH THIS SYSTEM.
BECAUSE OF THE FURTHER SOUTH AND WEST PATH OF THIS SYSTEM...THE
HIGHER WINDS HAVE BEEN PULLED FURTHER SOUTH AND WEST. DO EXPECT
BREEZY CONDITIONS BUT NOTHING STRONG ENOUGH TO WARRANT UPGRADING
THE BLIZZARD WATCH TO A WARNING.
SO BECAUSE OF THE DENSE FOG...JUST ENOUGH SNOW THAT WILL GET BLOWN
BY THE WIND...ADDED YUMA AND KIT CARSON TO THE WINTER WEATHER
ADVISORY AND EXPANDED THE ADVISORY THROUGH THE NIGHT SINCE EXPECT
BLOWING TO CONTINUE EVEN AFTER THE SNOW LETS UP. DUE TO THE MODELS
POOR HANDLING OF HIGH TEMPERATURES WITH THE SNOWFIELD...NOT VERY
CONFIDENT WITH THE MAXES TODAY WHICH ARE EVEN MORE COMPLEX.
MONDAY/MONDAY NIGHT...UPPER LOW KEEPS PULLING AWAY WITH THE OUTER
CONTOURS STILL NEAR THE AREA. GUT FEELING IS THAT DESPITE THE SIZE
OF THE SYSTEM...WITH IT MOVING AWAY AND THE DISTANCE IT IS FROM THE
AREA...FEEL THE QPF IS OVERBLOWN WITH MODELS AND SOME OF MY
NEIGHBORS HOLDING TO THIS TOO LONG. WILL KEEP THE A LOW CHANCE OF
SNOW BUT FEEL IT WILL NOT BE A LOT OF SNOW. WINDS WILL STAY UP AND
DEPENDING ON MUCH SNOW DOES FALL...THERE COULD BE SOME BLOWING SNOW
PROBLEMS. SO KEPT PATCHY BLOWING SNOW IN FOR THE FORECAST. HAVE NO
GOOD FEEL FOR TEMPERATURES.
TUESDAY/TUESDAY NIGHT...MODELS ALL OVER THE PLACE WITH HOW TO HANDLE
THIS TROUGH ONCE IT MOVES AWAY. THERE IS A POSSIBILITY OF SOME
LIGHT SNOW AND FLURRIES CONTINUING THROUGH THIS PERIOD.
.LONG TERM...(WEDNESDAY THROUGH SATURDAY NIGHT)
ISSUED AT 300 AM MST SUN FEB 24 2013
WEDNESDAY-WEDNESDAY NIGHT...RATHER TIGHT PRESSURE GRADIENT ACROSS
THE AREA DURING THE DAY LEADING TO BREEZY/WINDY NORTHWEST WINDS.
CLOUDINESS WILL DECREASE FROM WEST TO EAST LATE IN THE DAY WITH
MOSTLY CLEAR/PARTLY CLOUDY CONDITIONS DURING THE NIGHT AS PRIOR DAYS
STORM SYSTEM CONTINUES TO MOVE AWAY FROM THE AREA.
THURSDAY-THURSDAY NIGHT...UPPER FLOW STARTS TO AMPLIFY OFF THE WEST
COAST WHILE IN OUR AREA IT APPEARS AN UPPER LEVEL DISTURBANCE MOVES
THROUGH FROM THE NORTH/NORTHWEST. SHOULD HAVE SOME INCREASE IN
CLOUDINESS WITH IT. WILL NEED TO WATCH FOR A SMALL THREAT FOR LIGHT
PRECIPITATION LATE THURSDAY AFTERNOON PER 850-500 MOISTURE. JET
POSITION AND 850-500 MOISTURE MAY BE A BIT MORE FAVORABLE ACROSS FAR
EASTERN COLORADO AROUND 12Z FRIDAY.
FRIDAY-FRIDAY NIGHT...AMPLIFIED UPPER RIDGE SLOWLY MOVES ONSHORE AND
ACROSS THE WESTERN 1/4 OF THE COUNTRY. SMALL CHANCE FOR PRECIP
ACROSS FAR EASTERN COLORADO AT 12Z FRIDAY SLIDES SOUTHEAST ACROSS
THE REMAINDER OF THE AREA DURING THE DAY WITH ANOTHER BATCH OF
MOISTURE ALONG/AHEAD OF APPROACHING UPPER JET MOVING IN LATE FRIDAY
NIGHT. WILL KEEP SILENT POPS GOING FOR NOW
SATURDAY-SATURDAY NIGHT...UPPER RIDGE CONTINUES TO MOVE SLOWLY EAST
AND BY THE END OF THE PERIOD SHOULD BE ALONG AND WEST OF THE
CONTINENTAL DIVIDE. SHOULD HAVE SCATTERED CLOUDINESS THROUGH THE
PERIOD WITH DRY CONDITIONS EXPECTED.
TEMPERATURES THROUGH THE PERIOD BELOW NORMAL...NOT ONLY FROM CURRENT
SNOW COVER BUT 850 TEMPERATURES. A SLIGHT WARMUP EXPECTED...MAINLY
ALONG AND WEST OF THE CO/KS BORDER SATURDAY AND SUNDAY UNDER THE
APPROACHING UPPER RIDGE WHERE WARMER 850 TEMPERATURES MOVE INTO THE
AREA.
THANKS TO ALL FOR COLLABORATION THROUGH THE WHOLE PERIOD.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z MONDAY AFTERNOON)
ISSUED AT 1032 AM MST SUN FEB 24 2013
IFR TO VLIFR CONDITIONS WILL CONTINUE THROUGH MUCH OF THE PERIOD
AS COMBINATION OF FREEZING FOG/DRIZZLE AND LOW STRATUS CONTINUES.
WHILE VISIBILITY HAS BEEN SOMEWHAT VARIABLE...AND WILL LIKELY
BECOME MORE VARIABLE AS WINDS INCREASE...CIGS HAVE REMAINED IN THE
100 TO 400 FT RANGE AND THINK THEY WILL REMAIN SO THROUGH THE
EVENING INTO THE MORNING HOURS. WHILE BOTH TAF SITES WILL BE OUT
OF HEAVIER SNOW ACCUMULATIONS LINGERING FOG/LIGHT SNOW AND
POTENTIALLY BLOWING SNOW WILL KEEP VISIBILITIES UNDER 5 MILES AS
STRONG LOW DEVELOPS ACROSS OKLAHOMA TONIGHT.
&&
.GLD WATCHES/WARNINGS/ADVISORIES...
KS...WINTER WEATHER ADVISORY UNTIL 5 AM MST /6 AM CST/ MONDAY FOR
KSZ001>004-013>016-027>029-041-042.
CO...WINTER WEATHER ADVISORY UNTIL 5 AM MST MONDAY FOR COZ090>092.
NE...WINTER WEATHER ADVISORY UNTIL 5 AM MST /6 AM CST/ MONDAY FOR
NEZ079>081.
&&
$$
UPDATE...JRM
SHORT TERM...BULLER
LONG TERM...DDT
AVIATION...JRM
AREA FORECAST DISCUSSION
NWS GOODLAND KS
941 AM MST SUN FEB 24 2013
.UPDATE...
ISSUED AT 935 AM MST SUN FEB 24 2013
MADE A QUICK UPDATE TO FORECAST TO CONTINUE DENSE FOG/VERY LIGHT
FREEZING DRIZZLE THROUGH MUCH OF THE DAY AS VISIBILITIES REMAIN LOW
IN FOG ACROSS ALL BUT THE NORTHWEST SECTION OF CWA. ALSO MODIFIED
WX/SNOW GRIDS TO REFLECT CURRENT PRECIPITATION SHIELD WITH SNOW
BEGINNING TO ACCUMULATE AROUND YUMA CO. LATEST RUC HAS A VERY GOOD
HANDLE ON THE PRECIPITATION AND USED IT AS BASELINE FOR FORECAST
OVER NEXT 3-4 HOURS. WHILE THERE DOES APPEAR TO BE A POCKET OF
WEAKER STABILITY IN THE NORTHWEST...DOES NOT APPEAR TO BE
CO LOCATED WITH STRONGER MESOSCALE FORCING AND WILL KEEP AMOUNTS IN
THE 1 TO 3 IN RANGE FOR THE AFTERNOON. STILL ASSESSING NEWEST
GUIDANCE WITH RESPECT TO HOW SYSTEM DEVELOPS TOMORROW.
&&
.SHORT TERM...(TODAY THROUGH TUESDAY NIGHT)
ISSUED AT 416 AM MST SUN FEB 24 2013
MAIN FORECAST CONCERN WILL WINTER STORM THAT WILL AFFECT THE AREA
THROUGH MOST OF THE SHORT TERM. SATELLITE SHOWING A PROGRESSIVE FLOW
OVER THE PACIFIC. THIS TRANSITIONS TO A MORE AMPLIFIED AND SPLIT
FLOW OVER NORTH AMERICA. MAIN FEATURE OF INTEREST IS SYSTEM
DEVELOPING NEAR THE FOUR CORNERS.
AT JET LEVEL...THE ECMWF WAS DOING SLIGHTLY BETTER THAN THE REST OF
THE MODELS. AT MID LEVELS...SATELLITE AND UPPER AIR ANALYSIS WOULD
INDICATE THAT THE UKMET AND GFS HAVE THE BEST HANDLE ON INCOMING
STORM SYSTEM THROUGH. THE HIGH RESOLUTION NAM/RUC FOLLOWED BY THE
ECMWF GO THE SURFACE WIND/PRESSURE FIELD THE BEST. THE GFS AND NAM
WERE DOING SLIGHTLY BETTER ON THE LOW LEVEL THERMAL FIELD.
TODAY/TONIGHT...DRY MID LEVEL AIR IS BEING DRAWN UP AHEAD OF THE
UPPER SYSTEM. THIS IS ON TOP OF A RATHER MOIST LOW LEVELS PER
CURRENT OBSERVATIONS WITH STRATUS/FOG. MODELS SHOW THAT THE LEFT
FRONT QUADRANT IS AFFECT THE AREA AT 12Z. THIS MOVES SLOWLY SOUTH AND
EAST AND BY LATE AFTERNOON/EARLY EVENING IT IS SOUTH OF THE AREA.
COMPLEX UPPER LOW MOVES INTO THE AREA TODAY AND THEN SPLITS AND/OR
REDEVELOPS FURTHER SOUTH BEGINNING LATER TODAY INTO TONIGHT. MOST
NEW MODEL RUNS ARE FURTHER SOUTH WITH THIS LOW THAN YESTERDAY WITH
THE ENSEMBLES SHOWING THAT SAME TREND AS WELL. IN ADDITION TO BE
FURTHER SOUTH THE MODELS SHOWING THIS REDEVELOPMENT FURTHER WEST AS
WELL. MODELS ARE FURTHER WEST/SLOWER THAN YESTERDAY. ALL THESE TRENDS
MAKES SENSE WITH THE STRONGEST JET WINDS ON THE BACKSIDE OF THE
TROUGH WITH STILL LARGE HEIGHT FALLS AT THE BASE/BEHIND THE TROUGH.
SATELLITE SHOWING/CONFIRMING THIS NICELY.
VERY COMPLEX AND LOW CONFIDENCE FORECAST WITH A NUMBER OF ISSUES TO
ADDRESS. INITIALLY WILL HAVE DENSE FOG COVERING MOST OF THE AREA
THROUGH THE MORNING WITH THE MODELS STILL HAVING A HARD TIME WITH
THIS BUT THE HRRR SEEMS TO HAVE CAUGHT ONTO IT. BECAUSE OF THE
DRIER IN PLACE ABOVE THE SATURATED LOW LAYERS AND THE BETTER LIFT
FURTHER SOUTH AND WEST THAN BEFORE...ALSO NOT ALIGNING WELL WITH
EACH OTHER...AM NOT VERY OPTIMISTIC ABOUT VERY MUCH SNOW OCCURRING.
KEPT THE PATCHY FREEZING DRIZZLE IN THROUGH THE DAY. SNOW SHOULD
DEVELOP IN THE WEST ON THE BACKSIDE OF THE WEAKENING NORTHERN
PORTION OF THIS LOW. BY THE TIME THE SYSTEM GETS ITS ACT TOGETHER
IT IS TOO FAR SOUTH TO GIVE THE AREA A SIGNIFICANT AMOUNT OF SNOW.
SO ENDED UP CUTTING AMOUNTS. NEXT COMES THE WINDS WITH THIS SYSTEM.
BECAUSE OF THE FURTHER SOUTH AND WEST PATH OF THIS SYSTEM...THE
HIGHER WINDS HAVE BEEN PULLED FURTHER SOUTH AND WEST. DO EXPECT
BREEZY CONDITIONS BUT NOTHING STRONG ENOUGH TO WARRANT UPGRADING
THE BLIZZARD WATCH TO A WARNING.
SO BECAUSE OF THE DENSE FOG...JUST ENOUGH SNOW THAT WILL GET BLOWN
BY THE WIND...ADDED YUMA AND KIT CARSON TO THE WINTER WEATHER
ADVISORY AND EXPANDED THE ADVISORY THROUGH THE NIGHT SINCE EXPECT
BLOWING TO CONTINUE EVEN AFTER THE SNOW LETS UP. DUE TO THE MODELS
POOR HANDLING OF HIGH TEMPERATURES WITH THE SNOWFIELD...NOT VERY
CONFIDENT WITH THE MAXES TODAY WHICH ARE EVEN MORE COMPLEX.
MONDAY/MONDAY NIGHT...UPPER LOW KEEPS PULLING AWAY WITH THE OUTER
CONTOURS STILL NEAR THE AREA. GUT FEELING IS THAT DESPITE THE SIZE
OF THE SYSTEM...WITH IT MOVING AWAY AND THE DISTANCE IT IS FROM THE
AREA...FEEL THE QPF IS OVERBLOWN WITH MODELS AND SOME OF MY
NEIGHBORS HOLDING TO THIS TOO LONG. WILL KEEP THE A LOW CHANCE OF
SNOW BUT FEEL IT WILL NOT BE A LOT OF SNOW. WINDS WILL STAY UP AND
DEPENDING ON MUCH SNOW DOES FALL...THERE COULD BE SOME BLOWING SNOW
PROBLEMS. SO KEPT PATCHY BLOWING SNOW IN FOR THE FORECAST. HAVE NO
GOOD FEEL FOR TEMPERATURES.
TUESDAY/TUESDAY NIGHT...MODELS ALL OVER THE PLACE WITH HOW TO HANDLE
THIS TROUGH ONCE IT MOVES AWAY. THERE IS A POSSIBILITY OF SOME
LIGHT SNOW AND FLURRIES CONTINUING THROUGH THIS PERIOD.
.LONG TERM...(WEDNESDAY THROUGH SATURDAY NIGHT)
ISSUED AT 300 AM MST SUN FEB 24 2013
WEDNESDAY-WEDNESDAY NIGHT...RATHER TIGHT PRESSURE GRADIENT ACROSS
THE AREA DURING THE DAY LEADING TO BREEZY/WINDY NORTHWEST WINDS.
CLOUDINESS WILL DECREASE FROM WEST TO EAST LATE IN THE DAY WITH
MOSTLY CLEAR/PARTLY CLOUDY CONDITIONS DURING THE NIGHT AS PRIOR DAYS
STORM SYSTEM CONTINUES TO MOVE AWAY FROM THE AREA.
THURSDAY-THURSDAY NIGHT...UPPER FLOW STARTS TO AMPLIFY OFF THE WEST
COAST WHILE IN OUR AREA IT APPEARS AN UPPER LEVEL DISTURBANCE MOVES
THROUGH FROM THE NORTH/NORTHWEST. SHOULD HAVE SOME INCREASE IN
CLOUDINESS WITH IT. WILL NEED TO WATCH FOR A SMALL THREAT FOR LIGHT
PRECIPITATION LATE THURSDAY AFTERNOON PER 850-500 MOISTURE. JET
POSITION AND 850-500 MOISTURE MAY BE A BIT MORE FAVORABLE ACROSS FAR
EASTERN COLORADO AROUND 12Z FRIDAY.
FRIDAY-FRIDAY NIGHT...AMPLIFIED UPPER RIDGE SLOWLY MOVES ONSHORE AND
ACROSS THE WESTERN 1/4 OF THE COUNTRY. SMALL CHANCE FOR PRECIP
ACROSS FAR EASTERN COLORADO AT 12Z FRIDAY SLIDES SOUTHEAST ACROSS
THE REMAINDER OF THE AREA DURING THE DAY WITH ANOTHER BATCH OF
MOISTURE ALONG/AHEAD OF APPROACHING UPPER JET MOVING IN LATE FRIDAY
NIGHT. WILL KEEP SILENT POPS GOING FOR NOW
SATURDAY-SATURDAY NIGHT...UPPER RIDGE CONTINUES TO MOVE SLOWLY EAST
AND BY THE END OF THE PERIOD SHOULD BE ALONG AND WEST OF THE
CONTINENTAL DIVIDE. SHOULD HAVE SCATTERED CLOUDINESS THROUGH THE
PERIOD WITH DRY CONDITIONS EXPECTED.
TEMPERATURES THROUGH THE PERIOD BELOW NORMAL...NOT ONLY FROM CURRENT
SNOW COVER BUT 850 TEMPERATURES. A SLIGHT WARMUP EXPECTED...MAINLY
ALONG AND WEST OF THE CO/KS BORDER SATURDAY AND SUNDAY UNDER THE
APPROACHING UPPER RIDGE WHERE WARMER 850 TEMPERATURES MOVE INTO THE
AREA.
THANKS TO ALL FOR COLLABORATION THROUGH THE WHOLE PERIOD.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z MONDAY MORNING)
ISSUED AT 447 AM MST SUN FEB 24 2013
COMPLICATED TAFS WITH MODEL DATA HELPING MUCH AS THEY ARE HAVING
TROUBLE WITH THE CURRENT CONDITIONS. MODELS UNDERDOING THE EXTENT
OF THE DENSE FOG. THE HRRR AND TO A LESSER DEGREE THE RUC ARE
DOING WELL. VLIFR CONDITIONS ARE EXPECTED UNTIL LATE THIS
AFTERNOON TO EARLY AFTERNOON. IFR/LIFR CEILINGS ARE EXPECTED
THROUGH THE REST OF THE PERIOD. SNOW IS EXPECTED TO DEVELOP BUT
NOT UNTIL LATER THIS AFTERNOON TO EARLY EVENING. MVFR VSIBILITIES
ARE EXPECTED WHEN THE SNOW OCCURS.
&&
.GLD WATCHES/WARNINGS/ADVISORIES...
KS...WINTER WEATHER ADVISORY UNTIL 5 AM MST /6 AM CST/ MONDAY FOR
KSZ001>004-013>016-027>029-041-042.
CO...WINTER WEATHER ADVISORY UNTIL 5 AM MST MONDAY FOR COZ090>092.
NE...WINTER WEATHER ADVISORY UNTIL 5 AM MST /6 AM CST/ MONDAY FOR
NEZ079>081.
&&
$$
UPDATE...JRM
SHORT TERM...BULLER
LONG TERM...DDT
AVIATION...BULLER
AREA FORECAST DISCUSSION
NWS GOODLAND KS
451 AM MST SUN FEB 24 2013
.SHORT TERM...(TODAY THROUGH TUESDAY NIGHT)
ISSUED AT 416 AM MST SUN FEB 24 2013
MAIN FORECAST CONCERN WILL WINTER STORM THAT WILL AFFECT THE AREA
THROUGH MOST OF THE SHORT TERM. SATELLITE SHOWING A PROGRESSIVE FLOW
OVER THE PACIFIC. THIS TRANSITIONS TO A MORE AMPLIFIED AND SPLIT
FLOW OVER NORTH AMERICA. MAIN FEATURE OF INTEREST IS SYSTEM
DEVELOPING NEAR THE FOUR CORNERS.
AT JET LEVEL...THE ECMWF WAS DOING SLIGHTLY BETTER THAN THE REST OF
THE MODELS. AT MID LEVELS...SATELLITE AND UPPER AIR ANALYSIS WOULD
INDICATE THAT THE UKMET AND GFS HAVE THE BEST HANDLE ON INCOMING
STORM SYSTEM THROUGH. THE HIGH RESOLUTION NAM/RUC FOLLOWED BY THE
ECMWF GO THE SURFACE WIND/PRESSURE FIELD THE BEST. THE GFS AND NAM
WERE DOING SLIGHTLY BETTER ON THE LOW LEVEL THERMAL FIELD.
TODAY/TONIGHT...DRY MID LEVEL AIR IS BEING DRAWN UP AHEAD OF THE
UPPER SYSTEM. THIS IS ON TOP OF A RATHER MOIST LOW LEVELS PER
CURRENT OBSERVATIONS WITH STRATUS/FOG. MODELS SHOW THAT THE LEFT
FRONT QUADRANT IS AFFECT THE AREA AT 12Z. THIS MOVES SLOWLY SOUTH AND
EAST AND BY LATE AFTERNOON/EARLY EVENING IT IS SOUTH OF THE AREA.
COMPLEX UPPER LOW MOVES INTO THE AREA TODAY AND THEN SPLITS AND/OR
REDEVELOPS FURTHER SOUTH BEGINNING LATER TODAY INTO TONIGHT. MOST
NEW MODEL RUNS ARE FURTHER SOUTH WITH THIS LOW THAN YESTERDAY WITH
THE ENSEMBLES SHOWING THAT SAME TREND AS WELL. IN ADDITION TO BE
FURTHER SOUTH THE MODELS SHOWING THIS REDEVELOPMENT FURTHER WEST AS
WELL. MODELS ARE FURTHER WEST/SLOWER THAN YESTERDAY. ALL THESE TRENDS
MAKES SENSE WITH THE STRONGEST JET WINDS ON THE BACKSIDE OF THE
TROUGH WITH STILL LARGE HEIGHT FALLS AT THE BASE/BEHIND THE TROUGH.
SATELLITE SHOWING/CONFIRMING THIS NICELY.
VERY COMPLEX AND LOW CONFIDENCE FORECAST WITH A NUMBER OF ISSUES TO
ADDRESS. INITIALLY WILL HAVE DENSE FOG COVERING MOST OF THE AREA
THROUGH THE MORNING WITH THE MODELS STILL HAVING A HARD TIME WITH
THIS BUT THE HRRR SEEMS TO HAVE CAUGHT ONTO IT. BECAUSE OF THE
DRIER IN PLACE ABOVE THE SATURATED LOW LAYERS AND THE BETTER LIFT
FURTHER SOUTH AND WEST THAN BEFORE...ALSO NOT ALIGNING WELL WITH
EACH OTHER...AM NOT VERY OPTIMISTIC ABOUT VERY MUCH SNOW OCCURRING.
KEPT THE PATCHY FREEZING DRIZZLE IN THROUGH THE DAY. SNOW SHOULD
DEVELOP IN THE WEST ON THE BACKSIDE OF THE WEAKENING NORTHERN
PORTION OF THIS LOW. BY THE TIME THE SYSTEM GETS ITS ACT TOGETHER
IT IS TOO FAR SOUTH TO GIVE THE AREA A SIGNIFICANT AMOUNT OF SNOW.
SO ENDED UP CUTTING AMOUNTS. NEXT COMES THE WINDS WITH THIS SYSTEM.
BECAUSE OF THE FURTHER SOUTH AND WEST PATH OF THIS SYSTEM...THE
HIGHER WINDS HAVE BEEN PULLED FURTHER SOUTH AND WEST. DO EXPECT
BREEZY CONDITIONS BUT NOTHING STRONG ENOUGH TO WARRANT UPGRADING
THE BLIZZARD WATCH TO A WARNING.
SO BECAUSE OF THE DENSE FOG...JUST ENOUGH SNOW THAT WILL GET BLOWN
BY THE WIND...ADDED YUMA AND KIT CARSON TO THE WINTER WEATHER
ADVISORY AND EXPANDED THE ADVISORY THROUGH THE NIGHT SINCE EXPECT
BLOWING TO CONTINUE EVEN AFTER THE SNOW LETS UP. DUE TO THE MODELS
POOR HANDLING OF HIGH TEMPERATURES WITH THE SNOWFIELD...NOT VERY
CONFIDENT WITH THE MAXES TODAY WHICH ARE EVEN MORE COMPLEX.
MONDAY/MONDAY NIGHT...UPPER LOW KEEPS PULLING AWAY WITH THE OUTER
CONTOURS STILL NEAR THE AREA. GUT FEELING IS THAT DESPITE THE SIZE
OF THE SYSTEM...WITH IT MOVING AWAY AND THE DISTANCE IT IS FROM THE
AREA...FEEL THE QPF IS OVERBLOWN WITH MODELS AND SOME OF MY
NEIGHBORS HOLDING TO THIS TOO LONG. WILL KEEP THE A LOW CHANCE OF
SNOW BUT FEEL IT WILL NOT BE A LOT OF SNOW. WINDS WILL STAY UP AND
DEPENDING ON MUCH SNOW DOES FALL...THERE COULD BE SOME BLOWING SNOW
PROBLEMS. SO KEPT PATCHY BLOWING SNOW IN FOR THE FORECAST. HAVE NO
GOOD FEEL FOR TEMPERATURES.
TUESDAY/TUESDAY NIGHT...MODELS ALL OVER THE PLACE WITH HOW TO HANDLE
THIS TROUGH ONCE IT MOVES AWAY. THERE IS A POSSIBILITY OF SOME
LIGHT SNOW AND FLURRIES CONTINUING THROUGH THIS PERIOD.
.LONG TERM...(WEDNESDAY THROUGH SATURDAY NIGHT)
ISSUED AT 300 AM MST SUN FEB 24 2013
WEDNESDAY-WEDNESDAY NIGHT...RATHER TIGHT PRESSURE GRADIENT ACROSS
THE AREA DURING THE DAY LEADING TO BREEZY/WINDY NORTHWEST WINDS.
CLOUDINESS WILL DECREASE FROM WEST TO EAST LATE IN THE DAY WITH
MOSTLY CLEAR/PARTLY CLOUDY CONDITIONS DURING THE NIGHT AS PRIOR DAYS
STORM SYSTEM CONTINUES TO MOVE AWAY FROM THE AREA.
THURSDAY-THURSDAY NIGHT...UPPER FLOW STARTS TO AMPLIFY OFF THE WEST
COAST WHILE IN OUR AREA IT APPEARS AN UPPER LEVEL DISTURBANCE MOVES
THROUGH FROM THE NORTH/NORTHWEST. SHOULD HAVE SOME INCREASE IN
CLOUDINESS WITH IT. WILL NEED TO WATCH FOR A SMALL THREAT FOR LIGHT
PRECIPITATION LATE THURSDAY AFTERNOON PER 850-500 MOISTURE. JET
POSITION AND 850-500 MOISTURE MAY BE A BIT MORE FAVORABLE ACROSS FAR
EASTERN COLORADO AROUND 12Z FRIDAY.
FRIDAY-FRIDAY NIGHT...AMPLIFIED UPPER RIDGE SLOWLY MOVES ONSHORE AND
ACROSS THE WESTERN 1/4 OF THE COUNTRY. SMALL CHANCE FOR PRECIP
ACROSS FAR EASTERN COLORADO AT 12Z FRIDAY SLIDES SOUTHEAST ACROSS
THE REMAINDER OF THE AREA DURING THE DAY WITH ANOTHER BATCH OF
MOISTURE ALONG/AHEAD OF APPROACHING UPPER JET MOVING IN LATE FRIDAY
NIGHT. WILL KEEP SILENT POPS GOING FOR NOW
SATURDAY-SATURDAY NIGHT...UPPER RIDGE CONTINUES TO MOVE SLOWLY EAST
AND BY THE END OF THE PERIOD SHOULD BE ALONG AND WEST OF THE
CONTINENTAL DIVIDE. SHOULD HAVE SCATTERED CLOUDINESS THROUGH THE
PERIOD WITH DRY CONDITIONS EXPECTED.
TEMPERATURES THROUGH THE PERIOD BELOW NORMAL...NOT ONLY FROM CURRENT
SNOW COVER BUT 850 TEMPERATURES. A SLIGHT WARMUP EXPECTED...MAINLY
ALONG AND WEST OF THE CO/KS BORDER SATURDAY AND SUNDAY UNDER THE
APPROACHING UPPER RIDGE WHERE WARMER 850 TEMPERATURES MOVE INTO THE
AREA.
THANKS TO ALL FOR COLLABORATION THROUGH THE WHOLE PERIOD.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z MONDAY MORNING)
ISSUED AT 447 AM MST SUN FEB 24 2013
COMPLICATED TAFS WITH MODEL DATA HELPING MUCH AS THEY ARE HAVING
TROUBLE WITH THE CURRENT CONDITIONS. MODELS UNDERDOING THE EXTENT
OF THE DENSE FOG. THE HRRR AND TO A LESSER DEGREE THE RUC ARE
DOING WELL. VLIFR CONDITIONS ARE EXPECTED UNTIL LATE THIS
AFTERNOON TO EARLY AFTERNOON. IFR/LIFR CEILINGS ARE EXPECTED
THROUGH THE REST OF THE PERIOD. SNOW IS EXPECTED TO DEVELOP BUT
NOT UNTIL LATER THIS AFTERNOON TO EARLY EVENING. MVFR VSIBILITIES
ARE EXPECTED WHEN THE SNOW OCCURS.
&&
.GLD WATCHES/WARNINGS/ADVISORIES...
KS...WINTER WEATHER ADVISORY UNTIL 5 AM MST /6 AM CST/ MONDAY FOR
KSZ001>004-013>016-027>029-041-042.
CO...WINTER WEATHER ADVISORY UNTIL 5 AM MST MONDAY FOR COZ090>092.
NE...WINTER WEATHER ADVISORY UNTIL 5 AM MST /6 AM CST/ MONDAY FOR
NEZ079>081.
&&
$$
SHORT TERM...BULLER
LONG TERM...DDT
AVIATION...BULLER
AREA FORECAST DISCUSSION
NWS GOODLAND KS
416 AM MST SUN FEB 24 2013
.SHORT TERM...(TODAY THROUGH TUESDAY NIGHT)
ISSUED AT 416 AM MST SUN FEB 24 2013
MAIN FORECAST CONCERN WILL WINTER STORM THAT WILL AFFECT THE AREA
THROUGH MOST OF THE SHORT TERM. SATELLITE SHOWING A PROGRESSIVE FLOW
OVER THE PACIFIC. THIS TRANSITIONS TO A MORE AMPLIFIED AND SPLIT
FLOW OVER NORTH AMERICA. MAIN FEATURE OF INTEREST IS SYSTEM
DEVELOPING NEAR THE FOUR CORNERS.
AT JET LEVEL...THE ECMWF WAS DOING SLIGHTLY BETTER THAN THE REST OF
THE MODELS. AT MID LEVELS...SATELLITE AND UPPER AIR ANALYSIS WOULD
INDICATE THAT THE UKMET AND GFS HAVE THE BEST HANDLE ON INCOMING
STORM SYSTEM THROUGH. THE HIGH RESOLUTION NAM/RUC FOLLOWED BY THE
ECMWF GO THE SURFACE WIND/PRESSURE FIELD THE BEST. THE GFS AND NAM
WERE DOING SLIGHTLY BETTER ON THE LOW LEVEL THERMAL FIELD.
TODAY/TONIGHT...DRY MID LEVEL AIR IS BEING DRAWN UP AHEAD OF THE
UPPER SYSTEM. THIS IS ON TOP OF A RATHER MOIST LOW LEVELS PER
CURRENT OBSERVATIONS WITH STRATUS/FOG. MODELS SHOW THAT THE LEFT
FRONT QUADRANT IS AFFECT THE AREA AT 12Z. THIS MOVES SLOWLY SOUTH AND
EAST AND BY LATE AFTERNOON/EARLY EVENING IT IS SOUTH OF THE AREA.
COMPLEX UPPER LOW MOVES INTO THE AREA TODAY AND THEN SPLITS AND/OR
REDEVELOPS FURTHER SOUTH BEGINNING LATER TODAY INTO TONIGHT. MOST
NEW MODEL RUNS ARE FURTHER SOUTH WITH THIS LOW THAN YESTERDAY WITH
THE ENSEMBLES SHOWING THAT SAME TREND AS WELL. IN ADDITION TO BE
FURTHER SOUTH THE MODELS SHOWING THIS REDEVELOPMENT FURTHER WEST AS
WELL. MODELS ARE FURTHER WEST/SLOWER THAN YESTERDAY. ALL THESE TRENDS
MAKES SENSE WITH THE STRONGEST JET WINDS ON THE BACKSIDE OF THE
TROUGH WITH STILL LARGE HEIGHT FALLS AT THE BASE/BEHIND THE TROUGH.
SATELLITE SHOWING/CONFIRMING THIS NICELY.
VERY COMPLEX AND LOW CONFIDENCE FORECAST WITH A NUMBER OF ISSUES TO
ADDRESS. INITIALLY WILL HAVE DENSE FOG COVERING MOST OF THE AREA
THROUGH THE MORNING WITH THE MODELS STILL HAVING A HARD TIME WITH
THIS BUT THE HRRR SEEMS TO HAVE CAUGHT ONTO IT. BECAUSE OF THE
DRIER IN PLACE ABOVE THE SATURATED LOW LAYERS AND THE BETTER LIFT
FURTHER SOUTH AND WEST THAN BEFORE...ALSO NOT ALIGNING WELL WITH
EACH OTHER...AM NOT VERY OPTIMISTIC ABOUT VERY MUCH SNOW OCCURRING.
KEPT THE PATCHY FREEZING DRIZZLE IN THROUGH THE DAY. SNOW SHOULD
DEVELOP IN THE WEST ON THE BACKSIDE OF THE WEAKENING NORTHERN
PORTION OF THIS LOW. BY THE TIME THE SYSTEM GETS ITS ACT TOGETHER
IT IS TOO FAR SOUTH TO GIVE THE AREA A SIGNIFICANT AMOUNT OF SNOW.
SO ENDED UP CUTTING AMOUNTS. NEXT COMES THE WINDS WITH THIS SYSTEM.
BECAUSE OF THE FURTHER SOUTH AND WEST PATH OF THIS SYSTEM...THE
HIGHER WINDS HAVE BEEN PULLED FURTHER SOUTH AND WEST. DO EXPECT
BREEZY CONDITIONS BUT NOTHING STRONG ENOUGH TO WARRANT UPGRADING
THE BLIZZARD WATCH TO A WARNING.
SO BECAUSE OF THE DENSE FOG...JUST ENOUGH SNOW THAT WILL GET BLOWN
BY THE WIND...ADDED YUMA AND KIT CARSON TO THE WINTER WEATHER
ADVISORY AND EXPANDED THE ADVISORY THROUGH THE NIGHT SINCE EXPECT
BLOWING TO CONTINUE EVEN AFTER THE SNOW LETS UP. DUE TO THE MODELS
POOR HANDLING OF HIGH TEMPERATURES WITH THE SNOWFIELD...NOT VERY
CONFIDENT WITH THE MAXES TODAY WHICH ARE EVEN MORE COMPLEX.
MONDAY/MONDAY NIGHT...UPPER LOW KEEPS PULLING AWAY WITH THE OUTER
CONTOURS STILL NEAR THE AREA. GUT FEELING IS THAT DESPITE THE SIZE
OF THE SYSTEM...WITH IT MOVING AWAY AND THE DISTANCE IT IS FROM THE
AREA...FEEL THE QPF IS OVERBLOWN WITH MODELS AND SOME OF MY
NEIGHBORS HOLDING TO THIS TOO LONG. WILL KEEP THE A LOW CHANCE OF
SNOW BUT FEEL IT WILL NOT BE A LOT OF SNOW. WINDS WILL STAY UP AND
DEPENDING ON MUCH SNOW DOES FALL...THERE COULD BE SOME BLOWING SNOW
PROBLEMS. SO KEPT PATCHY BLOWING SNOW IN FOR THE FORECAST. HAVE NO
GOOD FEEL FOR TEMPERATURES.
TUESDAY/TUESDAY NIGHT...MODELS ALL OVER THE PLACE WITH HOW TO HANDLE
THIS TROUGH ONCE IT MOVES AWAY. THERE IS A POSSIBILITY OF SOME
LIGHT SNOW AND FLURRIES CONTINUING THROUGH THIS PERIOD.
.LONG TERM...(WEDNESDAY THROUGH SATURDAY NIGHT)
ISSUED AT 300 AM MST SUN FEB 24 2013
WEDNESDAY-WEDNESDAY NIGHT...RATHER TIGHT PRESSURE GRADIENT ACROSS
THE AREA DURING THE DAY LEADING TO BREEZY/WINDY NORTHWEST WINDS.
CLOUDINESS WILL DECREASE FROM WEST TO EAST LATE IN THE DAY WITH
MOSTLY CLEAR/PARTLY CLOUDY CONDITIONS DURING THE NIGHT AS PRIOR DAYS
STORM SYSTEM CONTINUES TO MOVE AWAY FROM THE AREA.
THURSDAY-THURSDAY NIGHT...UPPER FLOW STARTS TO AMPLIFY OFF THE WEST
COAST WHILE IN OUR AREA IT APPEARS AN UPPER LEVEL DISTURBANCE MOVES
THROUGH FROM THE NORTH/NORTHWEST. SHOULD HAVE SOME INCREASE IN
CLOUDINESS WITH IT. WILL NEED TO WATCH FOR A SMALL THREAT FOR LIGHT
PRECIPITATION LATE THURSDAY AFTERNOON PER 850-500 MOISTURE. JET
POSITION AND 850-500 MOISTURE MAY BE A BIT MORE FAVORABLE ACROSS FAR
EASTERN COLORADO AROUND 12Z FRIDAY.
FRIDAY-FRIDAY NIGHT...AMPLIFIED UPPER RIDGE SLOWLY MOVES ONSHORE AND
ACROSS THE WESTERN 1/4 OF THE COUNTRY. SMALL CHANCE FOR PRECIP
ACROSS FAR EASTERN COLORADO AT 12Z FRIDAY SLIDES SOUTHEAST ACROSS
THE REMAINDER OF THE AREA DURING THE DAY WITH ANOTHER BATCH OF
MOISTURE ALONG/AHEAD OF APPROACHING UPPER JET MOVING IN LATE FRIDAY
NIGHT. WILL KEEP SILENT POPS GOING FOR NOW
SATURDAY-SATURDAY NIGHT...UPPER RIDGE CONTINUES TO MOVE SLOWLY EAST
AND BY THE END OF THE PERIOD SHOULD BE ALONG AND WEST OF THE
CONTINENTAL DIVIDE. SHOULD HAVE SCATTERED CLOUDINESS THROUGH THE
PERIOD WITH DRY CONDITIONS EXPECTED.
TEMPERATURES THROUGH THE PERIOD BELOW NORMAL...NOT ONLY FROM CURRENT
SNOW COVER BUT 850 TEMPERATURES. A SLIGHT WARMUP EXPECTED...MAINLY
ALONG AND WEST OF THE CO/KS BORDER SATURDAY AND SUNDAY UNDER THE
APPROACHING UPPER RIDGE WHERE WARMER 850 TEMPERATURES MOVE INTO THE
AREA.
THANKS TO ALL FOR COLLABORATION THROUGH THE WHOLE PERIOD.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SUNDAY NIGHT)
ISSUED AT 1013 PM MST SAT FEB 23 2013
MVFR HAS BECOME WIDESPREAD ACROSS THE AREA WITH FOG ALONG WITH
PATCHY AREAS OF LIFR AND VLIFR DUE TO FREEZING FOG AND LOW
CEILINGS. CONDITIONS WILL CONTINUE TO DETERIORATE ACROSS THE
REGION WITH IFR AND LIFR BECOMING WIDESPREAD BETWEEN 09Z AND 12Z
WITH AREAS OF VLIFR. AREAS OF FREEZING DRIZZLE ARE ALSO EXPECTED
TO DEVELOP AFTER 09Z. LOW CEILINGS AND VISIBILITIES WILL CONTINUE
THROUGH THE TAF PERIOD WITH LIGHT SOUTHEAST WINDS TURNING
NORTHEAST AND BECOMING GUSTY BY 16Z. LIGHT SNOW WILL BE COMMON
AFTER 16Z WITH AREAS OF BLOWING SNOW POSSIBLE AS WINDS CONTINUE TO
INCREASE AND TURN NORTHERLY AFTER 00Z.
&&
.GLD WATCHES/WARNINGS/ADVISORIES...
KS...WINTER WEATHER ADVISORY UNTIL 5 AM MST /6 AM CST/ MONDAY FOR
KSZ001>004-013>016-027>029-041-042.
CO...WINTER WEATHER ADVISORY UNTIL 5 AM MST MONDAY FOR COZ090>092.
NE...WINTER WEATHER ADVISORY UNTIL 5 AM MST /6 AM CST/ MONDAY FOR
NEZ079>081.
&&
$$
SHORT TERM...BULLER
LONG TERM...DDT
AVIATION...LOCKHART
AREA FORECAST DISCUSSION
NWS DODGE CITY KS
500 AM CST SUN FEB 24 2013
...UPDATE TO AVIATION FOR 12Z TAFS...
.SYNOPSIS...
ISSUED AT 352 AM CST SUN FEB 24 2013
THE 00Z UPPER AIR ANALYSIS SHOWED A MID/UPPER LEVEL TROUGH OVER THE
GREAT BASIN. THIS TROUGH CONTINUES TO DEEPEN AS IT MOVES SOUTHEAST
AND SHOULD CONTINUE TO DO SO GIVEN A 130 KNOT UPPER LEVEL JET ON THE
BACK SIDE OF THE UPPER TROUGH AND 130 METER HEIGHT FALLS TO ITS
SOUTHEAST. AT THE SURFACE, LOW PRESSURE WAS DEEPENING OVER NORTHEAST
NEW MEXICO. EAST OF THE LOW, UPPER 20S TO LOW 30S DEWPOINTS WERE
SPREADING NORTHWARD TOWARD THE CENTRAL HIGH PLAINS. AREAS OF FOG AND
LOW STRATUS WERE OCCURRING OVER WEST CENTRAL AND NORTHWEST KANSAS
EARLY THIS MORNING WITH SOME INDICATIONS OF DEVELOPMENT INTO
SOUTHWEST KANSAS.
&&
.SHORT TERM...(TODAY THROUGH TONIGHT)
ISSUED AT 352 AM CST SUN FEB 24 2013
VISIBILITIES ACROSS SOUTHWEST KANSAS HAVE BEEN STAYING MOSTLY IN THE
MVFR CATEGORY THROUGH THE EARLY MORNING HOURS WITH THE FAR NORTHERN
LOCATIONS AROUND HAYS SEEING VISIBILITIES OCCASIONALLY DROPPING TO A
QUARTER TO HALF MILE IN FOG. THE RUC13 AND HRRR ARE PICKING UP ON
THE FOG AND ARE SHOWING SOME SIGNIFICANT DEVELOPMENT TO THE SOUTH
ACROSS MUCH OF WEST CENTRAL AND SOUTHWEST KANSAS THROUGH THE NEXT
FEW HOURS THROUGH SUNRISE. THE 11-3.9U FOG CHANNEL HAS BEEN SHOWING
SOME HINTS OF FOG/STRATUS DEVELOPMENT AROUND COLDWATER/MEDICINE
LODGE AND GREENSBURG OVER THE PAST HOUR SO IT APPEARS THAT THERE IS
STILL POTENTIAL FOR THE FOG TO DEVELOP. HAVE LEFT THE DENSE FOG
ADVISORY IN PLACE THROUGH 9AM. IF NOTHING HAPPENS BY SUNRISE THEN
THE ADVISORY MAY BE ADJUSTED OR CANCELLED SOONER.
CONDITIONS ARE CONTINUING TO COME TOGETHER FOR A SIGNIFICANT WINTER
WEATHER EVENT ACROSS PARTS OF THE CENTRAL HIGH PLAINS STARTING THIS
EVENING AND CONTINUING THROUGH MONDAY EVENING. THE 00Z RUNS OF THE
NAM/GFS AND ECMWF ALL SHOW AN UPPER LOW CLOSING OFF OVER NEW MEXICO
BY THIS EVENING AND THEN INTENSIFYING AS IT TRACKS EAST INTO THE RED
RIVER VALLEY ON MONDAY. THE MODELS ARE ALL SHOWING PRECIPITATION
DEVELOPING ACROSS SOUTHWEST KANSAS LATE THIS AFTERNOON AND TONIGHT.
INITIAL PRECIPITATION COULD BE IN THE FORM OF FREEZING DRIZZLE OVER
FAR WESTERN KANSAS BUT THINK THIS WILL BE SHORT LIVED AS THE MID
LEVELS MOISTEN UP AND THE RESULTANT SEEDER/FEEDER MECHANISM CHANGES
PRECIPITATION OVER TO SNOW. FAR SOUTH CENTRAL KANSAS MAY SEE A
RAIN/SNOW MIX FOR A TIME TONIGHT AS TEMPERATURES IN THE LOWER LEVELS
HOVER AT OR SLIGHTLY ABOVE ZERO. AT ANY RATE, SNOW SHOULD BE
DEVELOPING OVER ALL OF SOUTHWEST AND CENTRAL KANSAS AS THE NIGHT
GOES ON AND BECOME HEAVY AT TIMES. SNOWFALL ACCUMULATIONS COULD BE
AS MUCH AS TWO TO FIVE INCHES BY MONDAY MORNING. WITH NORTH WINDS
EXPECTED TO INCREASE TO AROUND 25 TO 35 MPH, THERE WILL BE
CONSIDERABLE BLOWING AND DRIFTING SNOW WITH WIDESPREAD VISIBILITIES
AT A QUARTER MILE OR LESS EXPECTED. WITH THIS IN MIND, HAVE UPGRADED
THE BLIZZARD WATCH TO A BLIZZARD WARNING FOR ALL OF SOUTHWEST INTO
WEST CENTRAL AND SOUTH CENTRAL KANSAS TONIGHT.
.LONG TERM...(MONDAY THROUGH SATURDAY)
ISSUED AT 400 AM CST SUN FEB 24 2013
BLIZZARD CONDITIONS WILL CONTINUE MONDAY. VERY DANGEROUS TRAVEL CONDITIONS
ARE EXPECTED ACROSS THE REGION WITH HEAVY MESOSCALE SNOW BANDS DEVELOPING
IN THE 700 HPA DEFORMATION AXIS IN COMBINATION WITH 30 KT SURFACE WINDS.
THE 00Z GUIDANCE STILL SUPPORTS THE ONGOING FORECAST WITH HEAVY SNOW
ACROSS KANSAS. THE NAM SUGGESTS AS HIGH AS 60 KT 850 HPA WINDS, WHICH
WOULD MEAN SUSTAINED WINDS POSSIBLY AS HIGH AS 35-40 KT AT THE SURFACE.
THE ECMWF IS WEAKER WITH THE WIND PROFILE. TRAVEL IS NOT RECOMMENDED
MONDAY...IT WILL BE VERY UNSAFE TRAVEL CONDITIONS WITH WHITEOUT CONDITIONS
AND VERY LARGE SNOWDRIFTS. FOR MORE SPECIFIC INFORMATION REGARDING THE
BLIZZARD, PLEASE SEE THE WARNING TEXT /WSWDDC/. CONDITIONS WILL TAPER
WEST TO EAST THROUGH TUESDAY MORNING AS THE CYCLONE MOVES SOUTHEAST
OF THE REGION.
THE REST OF THE FORECAST WAS LEFT AS IS FROM THE ALLBLEND SOLUTION DUE
TO TIME CONSTRAINTS. HIGHS WILL MODERATE INTO THE 30S AND 40S BY MIDWEEK,
ALTHOUGH THE ALLBLEND NUMBERS COULD BE ON THE HIGH SIDE IF THE HEAVY
SNOWPACK DOES COME INTO FRUITION. LOWS WILL BE IN THE TEENS AND 20S.
AGAIN, THESE VALUES COULD BE ON THE HIGH SIDE IF WE GET SIGNIFICANT
ADDITIONAL SNOWS. THE REST OF THE FORECAST LOOKS DRY AS UPPER LEVEL
RIDGING DEVELOPS OUT WEST AND A DRY NORTHERLY FLOW PATTERN PREVAILS
ACROSS WESTERN KANSAS.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z MONDAY MORNING)
ISSUED AT 500 AM CST SUN FEB 24 2013
LIFR CONDITIONS THIS MORNING IN ASSOCIATION WITH FOG. IMPROVEMENT TO
MVFR LATE MORNING AS FOG ERODES. LIFR CONDITIONS LIKELY AGAIN THIS
EVENING AS BLIZZARD STARTS WITH DETERIORATING CONDITIONS THEREAFTER.
&&
.PRELIMINARY POINT TEMPS/POPS...
DDC 32 24 32 18 / 40 90 90 60
GCK 32 22 33 13 / 40 80 80 30
EHA 32 18 33 16 / 40 80 80 30
LBL 33 21 33 14 / 30 90 90 30
HYS 30 24 31 21 / 40 80 80 60
P28 34 28 32 25 / 30 90 90 80
&&
.DDC WATCHES/WARNINGS/ADVISORIES...
DENSE FOG ADVISORY UNTIL 9 AM CST /8 AM MST/ THIS MORNING FOR
KSZ030-031-043>046-061>066-074>081-084>090.
BLIZZARD WARNING FROM 6 PM CST /5 PM MST/ THIS EVENING TO
MIDNIGHT CST /11 PM MST/ MONDAY NIGHT FOR KSZ030-031-043>046-
061>066-074>081-084>090.
&&
$$
SYNOPSIS...GERARD
SHORT TERM...GERARD
LONG TERM...SUGDEN
AVIATION...SUGDEN
AREA FORECAST DISCUSSION
NWS DODGE CITY KS
400 AM CST SUN FEB 24 2013
...UPDATE TO LONG TERM DISCUSSION...
.SYNOPSIS...
ISSUED AT 352 AM CST SUN FEB 24 2013
THE 00Z UPPER AIR ANALYSIS SHOWED A MID/UPPER LEVEL TROUGH OVER THE
GREAT BASIN. THIS TROUGH CONTINUES TO DEEPEN AS IT MOVES SOUTHEAST
AND SHOULD CONTINUE TO DO SO GIVEN A 130 KNOT UPPER LEVEL JET ON THE
BACK SIDE OF THE UPPER TROUGH AND 130 METER HEIGHT FALLS TO ITS
SOUTHEAST. AT THE SURFACE, LOW PRESSURE WAS DEEPENING OVER NORTHEAST
NEW MEXICO. EAST OF THE LOW, UPPER 20S TO LOW 30S DEWPOINTS WERE
SPREADING NORTHWARD TOWARD THE CENTRAL HIGH PLAINS. AREAS OF FOG AND
LOW STRATUS WERE OCCURRING OVER WEST CENTRAL AND NORTHWEST KANSAS
EARLY THIS MORNING WITH SOME INDICATIONS OF DEVELOPMENT INTO
SOUTHWEST KANSAS.
&&
.SHORT TERM...(TODAY THROUGH TONIGHT)
ISSUED AT 352 AM CST SUN FEB 24 2013
VISIBILITIES ACROSS SOUTHWEST KANSAS HAVE BEEN STAYING MOSTLY IN THE
MVFR CATEGORY THROUGH THE EARLY MORNING HOURS WITH THE FAR NORTHERN
LOCATIONS AROUND HAYS SEEING VISIBILITIES OCCASIONALLY DROPPING TO A
QUARTER TO HALF MILE IN FOG. THE RUC13 AND HRRR ARE PICKING UP ON
THE FOG AND ARE SHOWING SOME SIGNIFICANT DEVELOPMENT TO THE SOUTH
ACROSS MUCH OF WEST CENTRAL AND SOUTHWEST KANSAS THROUGH THE NEXT
FEW HOURS THROUGH SUNRISE. THE 11-3.9U FOG CHANNEL HAS BEEN SHOWING
SOME HINTS OF FOG/STRATUS DEVELOPMENT AROUND COLDWATER/MEDICINE
LODGE AND GREENSBURG OVER THE PAST HOUR SO IT APPEARS THAT THERE IS
STILL POTENTIAL FOR THE FOG TO DEVELOP. HAVE LEFT THE DENSE FOG
ADVISORY IN PLACE THROUGH 9AM. IF NOTHING HAPPENS BY SUNRISE THEN
THE ADVISORY MAY BE ADJUSTED OR CANCELLED SOONER.
CONDITIONS ARE CONTINUING TO COME TOGETHER FOR A SIGNIFICANT WINTER
WEATHER EVENT ACROSS PARTS OF THE CENTRAL HIGH PLAINS STARTING THIS
EVENING AND CONTINUING THROUGH MONDAY EVENING. THE 00Z RUNS OF THE
NAM/GFS AND ECMWF ALL SHOW AN UPPER LOW CLOSING OFF OVER NEW MEXICO
BY THIS EVENING AND THEN INTENSIFYING AS IT TRACKS EAST INTO THE RED
RIVER VALLEY ON MONDAY. THE MODELS ARE ALL SHOWING PRECIPITATION
DEVELOPING ACROSS SOUTHWEST KANSAS LATE THIS AFTERNOON AND TONIGHT.
INITIAL PRECIPITATION COULD BE IN THE FORM OF FREEZING DRIZZLE OVER
FAR WESTERN KANSAS BUT THINK THIS WILL BE SHORT LIVED AS THE MID
LEVELS MOISTEN UP AND THE RESULTANT SEEDER/FEEDER MECHANISM CHANGES
PRECIPITATION OVER TO SNOW. FAR SOUTH CENTRAL KANSAS MAY SEE A
RAIN/SNOW MIX FOR A TIME TONIGHT AS TEMPERATURES IN THE LOWER LEVELS
HOVER AT OR SLIGHTLY ABOVE ZERO. AT ANY RATE, SNOW SHOULD BE
DEVELOPING OVER ALL OF SOUTHWEST AND CENTRAL KANSAS AS THE NIGHT
GOES ON AND BECOME HEAVY AT TIMES. SNOWFALL ACCUMULATIONS COULD BE
AS MUCH AS TWO TO FIVE INCHES BY MONDAY MORNING. WITH NORTH WINDS
EXPECTED TO INCREASE TO AROUND 25 TO 35 MPH, THERE WILL BE
CONSIDERABLE BLOWING AND DRIFTING SNOW WITH WIDESPREAD VISIBILITIES
AT A QUARTER MILE OR LESS EXPECTED. WITH THIS IN MIND, HAVE UPGRADED
THE BLIZZARD WATCH TO A BLIZZARD WARNING FOR ALL OF SOUTHWEST INTO
WEST CENTRAL AND SOUTH CENTRAL KANSAS TONIGHT.
.LONG TERM...(MONDAY THROUGH SATURDAY)
ISSUED AT 400 AM CST SUN FEB 24 2013
BLIZZARD CONDITIONS WILL CONTINUE MONDAY. VERY DANGEROUS TRAVEL CONDITIONS
ARE EXPECTED ACROSS THE REGION WITH HEAVY MESOSCALE SNOW BANDS DEVELOPING
IN THE 700 HPA DEFORMATION AXIS IN COMBINATION WITH 30 KT SURFACE WINDS.
THE 00Z GUIDANCE STILL SUPPORTS THE ONGOING FORECAST WITH HEAVY SNOW
ACROSS KANSAS. THE NAM SUGGESTS AS HIGH AS 60 KT 850 HPA WINDS, WHICH
WOULD MEAN SUSTAINED WINDS POSSIBLY AS HIGH AS 35-40 KT AT THE SURFACE.
THE ECMWF IS WEAKER WITH THE WIND PROFILE. TRAVEL IS NOT RECOMMENDED
MONDAY...IT WILL BE VERY UNSAFE TRAVEL CONDITIONS WITH WHITEOUT CONDITIONS
AND VERY LARGE SNOWDRIFTS. FOR MORE SPECIFIC INFORMATION REGARDING THE
BLIZZARD, PLEASE SEE THE WARNING TEXT /WSWDDC/. CONDITIONS WILL TAPER
WEST TO EAST THROUGH TUESDAY MORNING AS THE CYCLONE MOVES SOUTHEAST
OF THE REGION.
THE REST OF THE FORECAST WAS LEFT AS IS FROM THE ALLBLEND SOLUTION DUE
TO TIME CONSTRAINTS. HIGHS WILL MODERATE INTO THE 30S AND 40S BY MIDWEEK,
ALTHOUGH THE ALLBLEND NUMBERS COULD BE ON THE HIGH SIDE IF THE HEAVY
SNOWPACK DOES COME INTO FRUITION. LOWS WILL BE IN THE TEENS AND 20S.
AGAIN, THESE VALUES COULD BE ON THE HIGH SIDE IF WE GET SIGNIFICANT
ADDITIONAL SNOWS. THE REST OF THE FORECAST LOOKS DRY AS UPPER LEVEL
RIDGING DEVELOPS OUT WEST AND A DRY NORTHERLY FLOW PATTERN PREVAILS
ACROSS WESTERN KANSAS.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SUNDAY NIGHT)
ISSUED AT 1151 PM CST SAT FEB 23 2013
WEAK UPSLOPE FLOW AND A MOIST BOUNDARY LAYER WILL AID IN THE
DEVELOPMENT OF FOG AND STRATUS LATER TONIGHT. THE LOW STRATUS AND
FOG WAS ALREADY DEVELOPING ALONG THE COLORADO BORDER AND IS EXPECTED
TO CONTINUE TO DEVELOP EASTWARD ACROSS SOUTHWEST INTO CENTRAL KANSAS
THROUGH THE PREDAWN HOURS. PREDOMINANTLY IFR CONDITIONS ARE EXPECTED
BY SUNRISE. VSBYS COULD IMPROVE TO MVFR DURING THE DAY ALONG WITH
SOME BREAKS IN THE LOW CLOUDS BUT ANY IMPROVEMENT WILL BE SHORT LIVED.
WINDS WILL SWITCH AROUND TO THE NORTH BY 00Z MONDAY AND SHOULD BE
INCREASING INTO THE 15 TO 25 KNOT RANGE DURING THE EVENING HOURS.
SOME LIGHT SNOW IS ALSO EXPECTED TO DEVELOP
&&
.PRELIMINARY POINT TEMPS/POPS...
DDC 32 24 32 18 / 40 90 90 60
GCK 32 22 33 13 / 40 80 80 30
EHA 32 18 33 16 / 40 80 80 30
LBL 33 21 33 14 / 30 90 90 30
HYS 30 24 31 21 / 40 80 80 60
P28 34 28 32 25 / 30 90 90 80
&&
.DDC WATCHES/WARNINGS/ADVISORIES...
DENSE FOG ADVISORY UNTIL 9 AM CST /8 AM MST/ THIS MORNING FOR
KSZ030-031-043>046-061>066-074>081-084>090.
BLIZZARD WARNING FROM 6 PM CST /5 PM MST/ THIS EVENING TO
MIDNIGHT CST /11 PM MST/ MONDAY NIGHT FOR KSZ030-031-043>046-
061>066-074>081-084>090.
&&
$$
SYNOPSIS...GERARD
SHORT TERM...GERARD
LONG TERM...SUGDEN
AVIATION...GERARD
AREA FORECAST DISCUSSION
NWS DODGE CITY KS
354 AM CST SUN FEB 24 2013
...UPDATED SYNOPSIS AND SHORT TERM DISCUSSION...
.SYNOPSIS...
ISSUED AT 352 AM CST SUN FEB 24 2013
THE 00Z UPPER AIR ANALYSIS SHOWED A MID/UPPER LEVEL TROUGH OVER THE
GREAT BASIN. THIS TROUGH CONTINUES TO DEEPEN AS IT MOVES SOUTHEAST
AND SHOULD CONTINUE TO DO SO GIVEN A 130 KNOT UPPER LEVEL JET ON THE
BACK SIDE OF THE UPPER TROUGH AND 130 METER HEIGHT FALLS TO ITS
SOUTHEAST. AT THE SURFACE, LOW PRESSURE WAS DEEPENING OVER NORTHEAST
NEW MEXICO. EAST OF THE LOW, UPPER 20S TO LOW 30S DEWPOINTS WERE
SPREADING NORTHWARD TOWARD THE CENTRAL HIGH PLAINS. AREAS OF FOG AND
LOW STRATUS WERE OCCURRING OVER WEST CENTRAL AND NORTHWEST KANSAS
EARLY THIS MORNING WITH SOME INDICATIONS OF DEVELOPMENT INTO
SOUTHWEST KANSAS.
&&
.SHORT TERM...(TODAY THROUGH TONIGHT)
ISSUED AT 352 AM CST SUN FEB 24 2013
VISIBILITIES ACROSS SOUTHWEST KANSAS HAVE BEEN STAYING MOSTLY IN THE
MVFR CATEGORY THROUGH THE EARLY MORNING HOURS WITH THE FAR NORTHERN
LOCATIONS AROUND HAYS SEEING VISIBILITIES OCCASIONALLY DROPPING TO A
QUARTER TO HALF MILE IN FOG. THE RUC13 AND HRRR ARE PICKING UP ON
THE FOG AND ARE SHOWING SOME SIGNIFICANT DEVELOPMENT TO THE SOUTH
ACROSS MUCH OF WEST CENTRAL AND SOUTHWEST KANSAS THROUGH THE NEXT
FEW HOURS THROUGH SUNRISE. THE 11-3.9U FOG CHANNEL HAS BEEN SHOWING
SOME HINTS OF FOG/STRATUS DEVELOPMENT AROUND COLDWATER/MEDICINE
LODGE AND GREENSBURG OVER THE PAST HOUR SO IT APPEARS THAT THERE IS
STILL POTENTIAL FOR THE FOG TO DEVELOP. HAVE LEFT THE DENSE FOG
ADVISORY IN PLACE THROUGH 9AM. IF NOTHING HAPPENS BY SUNRISE THEN
THE ADVISORY MAY BE ADJUSTED OR CANCELLED SOONER.
CONDITIONS ARE CONTINUING TO COME TOGETHER FOR A SIGNIFICANT WINTER
WEATHER EVENT ACROSS PARTS OF THE CENTRAL HIGH PLAINS STARTING THIS
EVENING AND CONTINUING THROUGH MONDAY EVENING. THE 00Z RUNS OF THE
NAM/GFS AND ECMWF ALL SHOW AN UPPER LOW CLOSING OFF OVER NEW MEXICO
BY THIS EVENING AND THEN INTENSIFYING AS IT TRACKS EAST INTO THE RED
RIVER VALLEY ON MONDAY. THE MODELS ARE ALL SHOWING PRECIPITATION
DEVELOPING ACROSS SOUTHWEST KANSAS LATE THIS AFTERNOON AND TONIGHT.
INITIAL PRECIPITATION COULD BE IN THE FORM OF FREEZING DRIZZLE OVER
FAR WESTERN KANSAS BUT THINK THIS WILL BE SHORT LIVED AS THE MID
LEVELS MOISTEN UP AND THE RESULTANT SEEDER/FEEDER MECHANISM CHANGES
PRECIPITATION OVER TO SNOW. FAR SOUTH CENTRAL KANSAS MAY SEE A
RAIN/SNOW MIX FOR A TIME TONIGHT AS TEMPERATURES IN THE LOWER LEVELS
HOVER AT OR SLIGHTLY ABOVE ZERO. AT ANY RATE, SNOW SHOULD BE
DEVELOPING OVER ALL OF SOUTHWEST AND CENTRAL KANSAS AS THE NIGHT
GOES ON AND BECOME HEAVY AT TIMES. SNOWFALL ACCUMULATIONS COULD BE
AS MUCH AS TWO TO FIVE INCHES BY MONDAY MORNING. WITH NORTH WINDS
EXPECTED TO INCREASE TO AROUND 25 TO 35 MPH, THERE WILL BE
CONSIDERABLE BLOWING AND DRIFTING SNOW WITH WIDESPREAD VISIBILITIES
AT A QUARTER MILE OR LESS EXPECTED. WITH THIS IN MIND, HAVE UPGRADED
THE BLIZZARD WATCH TO A BLIZZARD WARNING FOR ALL OF SOUTHWEST INTO
WEST CENTRAL AND SOUTH CENTRAL KANSAS TONIGHT.
.LONG TERM...(SUNDAY NIGHT THROUGH SATURDAY)
ISSUED AT 350 PM CST SAT FEB 23 2013
A SIGNIFICANT SHIFT WESTWARD IN THE DEVELOPMENT OF THE CYCLONE HAS
OCCURRED IN A NUMBER OF THE MODELS...ESPECIALLY THE GEM MODEL AND
THE HIGH RESOLUTION MODEL SUITE. CONFIDENCE HAS INCREASED ENOUGH TO
SUPPORT A BLIZZARD WATCH. THIS REPLACES THE WINTER STORM WATCH AS IT
NOW APPEARS THERE WILL BE A LONG-DURATION OF MODERATE TO HEAVY SNOW
AND NORTH WINDS 25-40 MPH. THIS WILL ALL UNFOLD LATE SUNDAY EVENING
AS THE INITIAL ROUND OF PRECIPITATION FORMS ACROSS THE TEXAS
PANHANDLE...AND LIFTS NORTHEASTWARD INTO SOUTHWEST KANSAS. THE
500MB LOW WILL DEEPEN FROM 542 DECAMETERS OVER EASTERN NEW MEXICO AT
06Z MONDAY TO 536 DECAMETERS NEAR WICHITA FALLS, TX AT 18Z MONDAY.
THIS ROBUST DEVELOPMENT WILL LEAD TO A TREMENDOUS DEVELOPMENT OF
COLD SECTOR PRECIPITATION AS MID LEVEL FLOW GAINS SOME EASTERLY
COMPONENT NORTH OF THE LOW. THIS WILL PULL ABUNDANT LOW LEVEL
MOISTURE INTO THE COLD SECTOR NORTH OF THE LOW. THE LATEST 15Z SREF
MEANS SHOW A DIRE SCENARIO OF WIDESPREAD 15 OR MORE INCHES OF SNOW
ACROSS MUCH OF KANSAS. THE ECMWF AND UKMET MODELS SHOW LESS STORM
TOTAL QPF ACROSS SOUTHWEST KANSAS AS IT IS NOT AS EXPANSIVE WITH THE
COMMA HEAD PRECIPITATION AS SOME OF THE HIGHER RESOLUTION MODELS ARE
SUGGESTING. MAKE NO MISTAKE, WHETHER WE RECEIVE 5 INCHES OR 15
INCHES OF SNOW, IMPACTS WILL BE SEVERE GIVEN A) ALREADY ESTABLISHED
SNOWPACK FROM EARLIER WEEK STORM LEADING TO IMMEDIATE
BLOWING/DRIFTING CONCERNS AND B) NORTH WINDS GUSTING OVER 50 MPH.
SHOULD THE SREF MEANS AND CANADIAN GEM MODEL COME TO FRUITION AND
MID LEVEL CYCLOGENESIS IS AS FAR WEST AND AS SIGNIFICANT AS THESE
MODELS SHOW...WE WILL HAVE A HISTORIC AND CRIPPLING EVENT TO DEAL
WITH ACROSS MUCH OF THE AREA.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SUNDAY NIGHT)
ISSUED AT 1151 PM CST SAT FEB 23 2013
WEAK UPSLOPE FLOW AND A MOIST BOUNDARY LAYER WILL AID IN THE
DEVELOPMENT OF FOG AND STRATUS LATER TONIGHT. THE LOW STRATUS AND
FOG WAS ALREADY DEVELOPING ALONG THE COLORADO BORDER AND IS EXPECTED
TO CONTINUE TO DEVELOP EASTWARD ACROSS SOUTHWEST INTO CENTRAL KANSAS
THROUGH THE PREDAWN HOURS. PREDOMINANTLY IFR CONDITIONS ARE EXPECTED
BY SUNRISE. VSBYS COULD IMPROVE TO MVFR DURING THE DAY ALONG WITH
SOME BREAKS IN THE LOW CLOUDS BUT ANY IMPROVEMENT WILL BE SHORT LIVED.
WINDS WILL SWITCH AROUND TO THE NORTH BY 00Z MONDAY AND SHOULD BE
INCREASING INTO THE 15 TO 25 KNOT RANGE DURING THE EVENING HOURS.
SOME LIGHT SNOW IS ALSO EXPECTED TO DEVELOP
&&
.PRELIMINARY POINT TEMPS/POPS...
DDC 32 24 32 18 / 40 90 90 60
GCK 32 22 33 13 / 40 80 80 30
EHA 32 18 33 16 / 40 80 80 30
LBL 33 21 33 14 / 30 90 90 30
HYS 30 24 31 21 / 40 80 80 60
P28 34 28 32 25 / 30 90 90 80
&&
.DDC WATCHES/WARNINGS/ADVISORIES...
DENSE FOG ADVISORY UNTIL 9 AM CST /8 AM MST/ THIS MORNING FOR
KSZ030-031-043>046-061>066-074>081-084>090.
BLIZZARD WARNING FROM 6 PM CST /5 PM MST/ THIS EVENING TO
MIDNIGHT CST /11 PM MST/ MONDAY NIGHT FOR KSZ030-031-043>046-
061>066-074>081-084>090.
&&
$$
SYNOPSIS...GERARD
SHORT TERM...GERARD
LONG TERM...UMSCHEID
AVIATION...GERARD
AREA FORECAST DISCUSSION
NWS CARIBOU ME
935 AM EST SUN FEB 24 2013
.SYNOPSIS...
LOW PRESSURE IS EXPECTED TO PASS SOUTH OF THE REGION TODAY AND
PASS SOUTH OF NOVA SCOTIA TONIGHT. HIGH PRESSURE WILL BUILD IN
TO THE REGION ON MONDAY.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
930 AM UPDATE...CHALLENGING FORECAST FOR TODAY AS A NORLUN-TYPE
EVENT LOOKS TO BE SETTING UP. THE CHALLENGE IS PREDICTING EXACTLY
WHERE THE BAND OF SNOW IS GOING TO DEVELOP, BUT BASED ON CURRENT
RADAR AND THE 3KM HRRR MODEL, BELIEVE THE HEAVIEST SNOW WILL BE
WEST OF AN ELLSWORTH-BANGOR-GREENVILLE LINE. OTHER THAN SOME MINOR
TWEAKS, HAVE KEPT THE PREVIOUS SHIFT`S SNOWFALL AMOUNTS UNTIL THE
SNOW BAND SETTLES IN PLACE. DID BACK DOWN ON POPS OVER NORTHERN
AREAS THOSE AREAS SHOULD SEE JUST SCATTERED SNOW SHOWERS THROUGH
THE REMAINDER OF THE DAY. THE REST OF THE FORECAST IS IN GOOD
SHAPE AND NO OTHER CHANGES WERE NEEDED.
PREVIOUS DISCUSSION...THE CHALLENGE THIS TERM WILL BE THE SNOW
AND WHETHER OR NOT TO EXTEND THE WINTER WEATHER ADVISORIES FURTHER
N AND E. DETAILS BELOW AND LENGTHY.
FIRST BATCH OF SNOW DIMINISHING SOME AS MID LEVEL FORCING HAS
WEAKENED FOR THE TIME BEING. 07Z SFC ANALYSIS SHOWED INVERTED
TROF HOLDING ACROSS WESTERN AND NORTHERN MAINE W/HIGH PRES HOLDING
STRONG INTO EASTERN MAINE. RECEIVED REPORTS OF 2-3 INCHES IN
SOUTHERN PISCATAQUIS COUNTY AND PORTIONS OF SWRN PENOBSCOT COUNTY.
THE OTHER CONCERN WILL BE ACROSS THE FAR NWRN AREA FOR THE ST.
JOHN VALLEY AS THE RADAR DOES SHOW ANOTHER BAND SETTING UP THIS
MORNING IN THE INVERTED TROF. THIS COULD TIP SNOWFALL AMOUNTS NEAR
ADVISORY CRITERIA W/IN THE 24 HR PERIOD. THIS WILL NEED TO BE
WATCHED. FURTHER S, LOW PRES OFF THE NJ COAST IS MOVING ENE AND IS
FCST TO REMAIN WELL S OF THE GULF OF MAINE BUT WILL PLAY A ROLE
AND THIS IS MENTIONED BELOW.
THE LATEST REGIONAL RADAR HAS PRECIP SHIELD FILLING BACK IN
ACROSS SRN MAINE AND MOVING NE TOWARD THE DOWNEAST REGION. ATTM,
THE UPPER LEVEL LOW IS FCST TO REORGANIZE E OF NANTUCKET AND MOVE
E. THIS SETUP APPEARS SIMILAR TO A NORLUN SETUP W/AN INVERTED TROF
EXTENDING OFF THE SFC LOW BACK ACROSS SRN MAINE. THE 00Z NAM/CANADIAN
GEM AND TO SOME EXTENT THE GFS HAD A DECENT HANDLE ON THE LATEST
SETUP PER THE RADAR AND SFC ANALYSIS. Q-VECTOR FORCING FCST TO
SET UP BACK ACROSS INTERIOR DOWNEAST EXTENDING BACK UP INTO THE
CENTRAL HIGHLANDS(GNR-KOKADJO) TODAY RIGHT INTO EARLY TONIGHT AND
THEN WEAKEN. THIS WOULD ENHANCE SNOWFALL ACROSS THE CENTRAL
HIGHLANDS DOWN TO THE COAST, WHILE FURTHER N, THE FORCING IS SHOWN
TO WEAKEN BY THE AFTERNOON. THEREFORE, DECIDED TO BOOST SNOWFALL
TOTALS ESPECIALLY IN THE ADVISORY AREA USING A 17-20:1 SNOWFALL
RATIO GIVEN WHAT HAD FALLEN OVERNIGHT W/HIGH RATIOS. THIS MATCHES
UP WELL W/THE LATEST BUFKIT SHOWING DECENT SNOW IN THE DENTRITIC
ZONE ABOVE 850MBS. THIS MEANS SNOWFALL TOTALS OF 4 TO 7 INCHES
W/THE HIGHEST TOTALS FOR THE INTERIOR DOWNEAST TO THE COAST. THE
SNOWFALL TOTALS RUN FROM LAST NIGHT THROUGH TONIGHT WHICH COVER A
30HR PERIOD. THE NAM INDICATES A PERIOD OF POSSIBLY HEAVY SNOWFALL
IN A NARROW CORRIDOR FORM BANGOR TO ELLSWORTH AND POSSIBLY THE BAR
HARBOR. THIS WILL BE MONITORED FURTHER THIS MORNING.
THE ACTIVITY IS FCST TO WIND DOWN TONIGHT AS THE LOW PULLS FURTHER
AWAY AND THE FORCING WEAKENS. FOR THE POPS, USED THE SREF/GFS AND
NAM AND THEN ADJUSTED MANUALLY THIS MORNING TO FIT THE RADAR TRENDS.
THE QPF FOR THIS EVENT IS A BLEND OF HPC/GFS AND 00Z NERFC WHICH
SHOWS .30-.50 INCHES IN THE ADVISORY AREA W/THE HIGHEST TOTALS
ACROSS THE DOWNEAST REGION.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH TUESDAY/...
LOW PRESSURE WILL CONTINUE TO MOVE WELL EAST OF THE NEW ENGLAND
COAST MONDAY. LOW CLOUDS WILL LIKELY LINGER FOR A TIME AT LEAST FOR
THE FIRST PART OF THE DAY BEFORE DRIER AIR AND INCREASING SUBSIDENCE
ASSOCIATED WITH HIGH PRESSURE BUILDING IN FROM THE WEST ALLOWS FOR
AT LEAST PARTIAL CLEARING LATER MONDAY AFTERNOON.
MONDAY NIGHT SHOULD SEE MAINLY CLEAR TO PARTLY CLOUDY SKIES ACROSS
THE FA WITH SURFACE HIGH PRESSURE ACROSS THE REGION. SOME
RADIATIONAL COOLING IS LIKELY ESPECIALLY ACROSS NORTHERN AND EASTERN
PORTIONS.
THE SURFACE HIGH WILL MOVE EAST TUESDAY WITH INCREASING CLOUDS
DURING TUESDAY AFTERNOON.
HIGH TEMPERATURES BOTH MONDAY AND TUESDAY WILL BE ABOVE NORMAL FOR
THIS TIME OF YEAR WITH LOWER 30S NORTH AND MID TO UPPER 30S
DOWNEAST. LOW TEMPERATURES MONDAY NIGHT WILL RANGE FROM ZERO TO 5
ABOVE ACROSS THE SJV TO THE MID TO UPPER TEENS ACROSS INTERIOR
DOWNWEAST AND COASTAL MAINE.
&&
.LONG TERM /TUESDAY NIGHT THROUGH SATURDAY/...
CUTOFF LOW SLOWLY MOVE EAST OF THE NEW ENGLAND COAST THROUGH
FRIDAY. THIS SYSTEM WILL LIKELY KEEP AN UNSETTLED WEATHER PATTERN
ACROSS THE REGION THROUGH MUCH OF THE MID TO LATE WEEK PERIOD.
STILL PREFER THE DRIER ECMWF SOLUTION FOR WEDNESDAY WITH
MODERATELY STRONG SURFACE HIGH TO THE NORTH OF THE FORECAST AREA.
THUS...WILL CONTINUE TO ADVERTISE DRY WEATHER ACROSS NORTHER AND
EASTERN PORTIONS OF THE FA WEDNESDAY WITH CHANCE POPS DOWNEAST.
BEYOND WEDNESDAY WILL CONTINUE TO ADVERTISE CHANCE TO LOW END
LIKELY POPS AS THE HIGH TO THE NORTH BEGINS TO BREAK DOWN.
PRECIPITATION TYPE DURING THIS PERIOD WILL LIKELY BE SNOW OR
RAINSHOWERS BY DAY WITH SURFACE TEMPERATURES IN THE LOW TO MID 30S
AND SNOW SHOWERS BY NIGHT.
&&
.AVIATION /15Z SUNDAY THROUGH THURSDAY/...
NEAR TERM: MVFR/IFR EXPECTED THROUGH TONIGHT W/SNOW FOR ALL THE
TERMINALS. THERE IS EXPECTED TO BE PERIODS OF VFR EARLY TODAY.
SHORT TERM: MVFR CIGS ARE EXPECTED THROUGH MONDAY MORNING THEN
CIGS SHOULD LIFT TO VFR BY MONDAY AFTERNOON. VFR CONDITIONS ARE
EXPECTED MONDAY NIGHT THROUGH TUE. MVFR CONDITIONS LIKELY WED AND
THU.
&&
.MARINE...
NEAR TERM: SCA CONTINUES AND WILL POSSIBLY NEED TO BE EXTENDED
INTO TONIGHT ESPECIALLY FOR HAZARDOUS SEAS. ATTM, CONDITIONS ARE
BELOW SCA LEVELS BUT ARE PICKING UP. EXPECTATION IS THAT WINDS
WILL BE CLOSE TO SCA BY LATER THIS MORNING INTO EARLY AFTERNOON
AND THEN FALL BACK AS THE LOW PULLS AWAY. A SWELL COMPONENT IS
EXPECTED TO SET UP LATER TODAY AND CONTINUE THROUGH TONIGHT. THIS
COULD VERY WELL KEEP WAVE HEIGHTS ABV 6 FT.
SHORT TERM: WINDS/SEAS WILL REMAIN BELOW SCA LEVELS THROUGH MONDAY
THROUGH TUE NIGHT. WINDS/SEAS WILL INCREASE TO SCA LEVELS BY
WED.&&
.CAR WATCHES/WARNINGS/ADVISORIES...
ME...WINTER WEATHER ADVISORY UNTIL MIDNIGHT EST TONIGHT FOR MEZ003-
004-010-015-016-029-031.
MARINE...SMALL CRAFT ADVISORY FROM 7 AM THIS MORNING TO MIDNIGHT EST
TONIGHT FOR ANZ050>052.
&&
.CAR WATCHES/WARNINGS/ADVISORIES...
ME...WINTER WEATHER ADVISORY UNTIL MIDNIGHT EST TONIGHT FOR MEZ003-
004-010-015-016-029-031.
MARINE...SMALL CRAFT ADVISORY UNTIL MIDNIGHT EST TONIGHT FOR ANZ050>052.
&&
$$
NEAR TERM...HASTINGS/HEWITT
SHORT TERM...DUDA
LONG TERM...DUDA
AVIATION...HASTINGS/HEWITT
MARINE...HASTINGS/HEWITT/DUDA
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
801 PM EST MON FEB 25 2013
.SHORT TERM...(THIS EVENING THROUGH TUESDAY)
ISSUED AT 413 PM EST MON FEB 25 2013
WATER VAPOR IMAGERY AND RUC ANALYSIS SHOW A SPLIT FLOW PATTERN
ACROSS NAMERICA. IN THE SRN STREAM...A WELL-DEFINED MID LEVEL LOW
WAS OVER N TX. IN THE NRN STREAM...A SHORTWAVE TROF EXTENDS FROM
HUDSON BAY TO THE UPPER MISSISSIPPI VALLEY. SOME FLURRIES HAVE BEEN
NOTED IN WI TODAY IN AN AREA OF WEAK ISENTROPIC ASCENT. SOME OF
THOSE FLURRIES MAY HAVE SLIPPED INTO SCTNRL UPPER MI THIS AFTN
ALTHOUGH NO REPORTS HAVE BEEN NOTED. OTHERWISE...MOSTLY CLOUDY SKIES
HAVE BEEN THE RULE TODAY...THOUGH THERE WAS A PERIOD OF MOSTLY SUNNY
SKIES FOR A TIME EARLIER OVER THE FAR W AND NW.
ALTHOUGH THE SHORT TERM PORTION OF THE FCST WILL FEATURE TRANQUIL
WEATHER...CLOUDS AND TEMPS WILL OFFER SOME CHALLENGING ASPECTS TO
THE FCST. UNDER WEAK ISENTROPIC ASCENT...WILL MAINTAIN A MENTION OF
A FEW FLURRIES INTO THE EVENING HRS OVER THE SRN PORTION OF THE FCST
AREA. CLOUD FCST IS NOT CERTAIN AT ALL AND THAT OPENS THE DOOR TO
BIG TEMP BUST POTENTIAL TONIGHT. UNDER LIGHT SW FLOW INTO THE
EVENING...MULTI-LAYERED CLOUDS TO THE SW SHOULD AFFECT MUCH OF THE
FCST AREA. OVERNIGHT...LOW-LEVEL WIND FIELDS BECOME VERY LIGHT WITH
A TREND TO LIGHT EASTERLY LATE WHICH SUGGESTS LITTLE ADVECTION OF
DRIER AIR. THUS...IT WOULD SEEM THAT MUCH OF THE AREA WILL SEE
MOSTLY CLOUDY SKIES TONIGHT. HOWEVER...THE PROXIMITY OF CLEAR SKIES
JUST TO THE W SUGGESTS THE WRN FCST AREA MAY HAVE THE BEST SHOT OF
SEEING A PERIOD OF PARTLY CLOUDY AND POSSIBLY CLEAR SKIES TONIGHT.
ALL IN ALL...THERE IS VERY LOW CONFIDENCE ON SKY CONDITION THRU THE
NIGHT. WITH LIGHT/CALM WINDS AT THE SFC...TEMPS WILL FALL
SIGNIFICANTLY IN SOME AREAS IF SKIES BECOME CLEAR/PARTLY CLOUDY FOR
A TIME. THIS COULD ALSO LEAD TO SOME FOG DEVELOPMENT. AT THIS
POINT...WILL PLAY IT CONSERVATIVE UTILIZING A CONSENSUS APPROACH TO
TEMPS...BUT WILL GO WITH LOWEST MIN TEMPS OVER THE W (MID TEENS)
WHERE IT APPEARS THERE IS A BETTER SHOT OF SEEING LESS CLOUDS FOR AT
LEAST A PORTION OF THE NIGHT. COULD EASILY SEE TEMPS FALL INTO THE
SINGLE DIGITS IF ANY LOCATIONS END UP CLEAR FOR A FEW HRS.
E TO NE WINDS WILL DEVELOP TUE AS UPPER MI FALLS INTO THE NRN
PERIPHERY OF THE CIRCULATION AROUND SRN STREAM LOW. WINDS WILL BE
STRONGEST IN THE MENOMINEE AREA AS A STIFF NE WIND WILL BE THE RULE
IN THE AFTN DUE TO COASTAL CONVERGENCE/FUNNELING DOWN THE BAY.
STRATOCU SHOULD TEND TO BREAK UP AS MODELS SUGGEST SOME DRYING...
BUT THE LWR CLOUDS WILL PROBABLY HANG ON LONGEST WHERE EASTERLY
WINDS UPSLOPE. WHERE LOW CLOUDS SCATTER OUT OR CLEAR...THERE SHOULD
BE A FAIR AMOUNT OF SUNSHINE THRU ONLY SOME HIGH CLOUDS. EXPECT MAX
TEMPS IN THE 30S...COOLEST (LOW 30S) AT LOCATIONS WHERE WINDS ARE
OFF THE LAKES AND IN THE UPSLOPE AREAS. TEMPS COULD RISE TO NEAR 40
IN LOCATIONS THAT SEE DOWNSLOPING WITH EASTERLY WINDS.
.LONG TERM...(TUESDAY NIGHT THROUGH MONDAY)
ISSUED AT 413 PM EST MON FEB 25 2013
THREE SHORTWAVES WILL INFLUENCE THE WEATHER FOR MUCH OF THE EASTERN
HALF OF THE CONUS OVER THE NEXT SEVERAL DAYS AND SETUP THE WEATHER
PATTERN HEADING INTO THE FIRST WEEK OF MARCH.
THE FIRST WAVE IS CURRENTLY SPINNING IN THE SOUTHERN PLAINS AND WILL
EJECT TOWARDS THE LOWER GREAT LAKES ON TUESDAY INTO TUESDAY
NIGHT...WHILE THE NEXT WAVE DIVES SOUTHEAST ACROSS THE CENTRAL
ROCKIES. MODELS HAVE BECOME MUCH MORE CONSISTENT WITH THIS SYSTEM IN
THE LAST 24 HOURS...AS THERE WERE DIFFERENCES IN THE INTERACTION
BETWEEN THE FIRST AND SECOND WAVES...WITH THE MERGER AND NORTHWARD
EXTENT. EVERYTHING SEEMS TO HAVE COME INTO AGREEMENT WITH THE
CONSISTENT ECMWF ON A MORE SOUTHERN TRACK THAT JUST BRUSHES THE FAR
SOUTHEAST PART OF UPPER MICHIGAN /NEAR LAKE MICHIGAN/ WITH LIGHT
SNOW LATE TUESDAY NIGHT INTO WEDNESDAY EVENING. ANY SLIGHT
DIFFERENCES IN THE NORTHWEST EXTENT OF THE TRACK WILL NOT ONLY
AFFECT THE SNOW NEAR LAKE MICHIGAN...BUT ALSO THE POTENTIAL FOR
LIGHT LAKE ENHANCEMENT OR UPSLOPE PRECIPITATION WITH THE
NORTH-NORTHEAST FLOW AROUND THE LOW. WITH THE LIMITED COLD AIR IN
PLACE AT THIS TIME...IT LOOKS LIKE 850MB TEMPS ON WEDNESDAY ARE ONLY
AROUND -5C...SO DELTA-T VALUES ARE FAIRLY MARGINAL. WHEN COMBINING
THAT WITH LIMITED MOISTURE...UNLESS THE FARTHER NW 06Z NAM IS
CORRECT...WOULDN/T THINK AREAS AWAY FROM LAKE MICHIGAN WOULD SEE
MUCH MORE THAN LOW CLOUDS AND UPSLOPE FLURRIES OR LIGHT SNOW OVER
THE NORTH CENTRAL ON WEDNESDAY PENDING ENOUGH MOISTURE. MODELS ARE
IN BETTER AGREEMENT ON LOW LEVEL MOISTURE MOVING IN ON WEDNESDAY
NIGHT AS THE LOW SHIFTS EAST INTO NEW YORK. THIS IS IN RESPONSE TO
ADDITIONAL MOISTURE ASSOCIATED WITH A NORTHERN STREAM SHORTWAVE
MOVING THROUGH SOUTHERN CANADA. THIS WILL LIKELY LEAD TO THE BEST
POTENTIAL FOR PRECIPITATION FOR AREAS NEAR LAKE SUPERIOR WEDNESDAY
NIGHT INTO THURSDAY. 850MB TEMPS ARE STILL MARGINAL THROUGH THIS
PERIOD...BUT DO DROP TO -10C. WITH THE MARGINAL DELTA-T VALUES AND
AN INVERSION HEIGHT SITTING AROUND 4KFT...THINKING THAT THE LIGHT
SNOW SHOWERS WILL REMAIN IN THE NORTH-NORTHEAST FAVORED LOCATIONS OF
NORTHERN UPPER MICHIGAN. STRONGEST SHOWERS SHOULD OCCUR OVER THE
HIGHER TERRAIN OF NORTH CENTRAL UPPER MICHIGAN...WHERE UPSLOPE FLOW
WILL AID THE FORCING SOME. WILL CONTINUE TO MENTION SLIGHTS AND LOW
CHANCE POPS IN THESE AREAS INTO THURSDAY NIGHT.
MEANWHILE...THE THIRD MAIN SHORTWAVE WILL BE DIVING SOUTHEAST
THROUGH THE ROCKIES ON WEDNESDAY NIGHT AND THURSDAY AND AMPLIFY THE
UPPER TROUGH OVER THE EASTERN CONUS. THIS WILL LEAD THE UPPER GREAT
LAKES INTO A COLDER THAN NORMAL PERIOD FOR THE LAST DAY OF FEBRUARY
AND THE FIRST WEEK OF MARCH. WHILE THIS BRINGS GRADUALLY COLDER AIR
/925-900MB TEMPS FALLING TOWARDS -12 TO -14C/...IT WILL ALSO PUSH A
HIGH PRESSURE RIDGE OVER THE AREA FROM A HIGH CENTERED OVER HUDSON
BAY. THIS SUBSIDENCE WILL WORK TO LOWER THE INVERSION HEIGHTS BELOW
3KFT BY FRIDAY MORNING. THEREFORE...WOULD JUST EXPECT LINGERING
LOW CLOUDS AND AN ISOLATED SNOW SHOWER FOR FRIDAY INTO SATURDAY
OVER LOCATIONS NEAR LAKE SUPERIOR. THERE ARE SOME DIFFERENCES IN
THE WIND DIRECTION ROTATING AROUND THE HIGH...BUT WILL MAINLY FOCUS
THE SLIGHT CHANCES OVER THE NORTH CENTRAL.
DIFFERENCES ARRIVE HEADING INTO THE SECOND HALF OF THE WEEKEND WITH
THE HANDLING OF A SHORTWAVE DROPPING THROUGH ON THE BACK SIDE OF
THE RIDGE OVER THE WESTERN CONUS. THE 00Z ECMWF KEEPS THE RIDGE
FARTHER TO THE WEST BEHIND THE SHORTWAVE...WHILE THE 12Z GFS PUSHES
IT INTO THE UPPER GREAT LAKES. DEPENDING ON THE SOLUTION...THIS
WILL EITHER KEEP THE AREA UNDER THE SURFACE RIDGE INTO THE FIRST
PART OF NEXT WEEK OR HAVE THE AREA INFLUENCED BY THE NEXT CLIPPER
SYSTEM APPROACHING FOR MONDAY. WILL GO WITH THE PERSISTENT HIGH AND
DRIER SOLUTION INTO MONDAY.
AFTER A FAIRLY ACTIVE PERIOD FOR THE LAST COUPLE OF WEEKS OF
FEBRUARY...IT/S LOOKING LIKE MARCH WILL COME IN LIKE A LAMB FOR
MUCH OF THE UPPER GREAT LAKES REGION. FORTUNATELY...THIS ACTIVE
PERIOD BROUGHT THE AREA CLOSER TO NORMAL SNOWFALL...ALTHOUGH SOME
LOCATIONS ARE STILL BELOW NORMAL ON SNOWFALL /OUR OFFICE/ AND SNOW
WATER EQUIVALENT /MICHIGAMME RIVER BASIN/. BUT LOOKING AT MODEL RUN
QPF...THE NEXT 10 DAYS DON/T APPEAR TO BE TOO PROMISING FOR
ADDITIONS TO THE SNOW PACK. 00Z ECMWF ONLY SHOWS 10 DAY ACCUMULATION
OF 0.02-0.08 INCH FOR THE ENTIRE CWA. 00Z GFS FOR THE
SIMILAR PERIOD KEEPS VALUES UNDER 0.25 OF AN INCH...WITH MUCH OF
THAT COMING FROM THE SYSTEM BRUSHING THE AREA ON WEDNESDAY AND
THURSDAY. ON THE POSITIVE SIDE...THE EXISTING SNOWPACK WILL REMAIN
IN PLACE AS TEMPERATURES TREND TOWARDS A COOLER THAN NORMAL PERIOD
FOR THE AREA FRIDAY INTO THE NEXT WORK WEEK /HIGHS IN THE 20S AND
LOWS IN THE SINGLE DIGITS ABOVE ZERO/.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z TUESDAY EVENING)
ISSUED AT 800 PM EST MON FEB 25 2013
EXPECT PREVAILING MVFR CIGS AT ALL TAF SITES THROUGH MUCH OF THE
EVENING. IF CLEARING SHOULD OCCUR LATER THIS EVENING/OVERNIGHT WITH
INCREASED RDGG/SUBSIDENCE ALOFT...FOG AND POSSIBLE IFR CONDITIONS
COULD DEVELOP AT ALL TAF SITES LATE TONIGHT. EXPECT IMPROVING
CONDITIONS ON TUESDAY WITH A RETURN TO VFR CONDITIONS BY LATE
MORNING/EARLY AFTERNOON.
&&
.MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 413 PM EST MON FEB 25 2013
ALTHOUGH HIGH PRES WILL BE DEPARTING...WINDS WILL REMAIN UNDER 20KT
PROBABLY THRU TUE AFTN. THEREAFTER...TIGHTENING PRES GRADIENT BTWN
HIGH PRES TO THE N AND NW AND LOW PRES TRACKING THRU THE LOWER OHIO
VALLEY TO LOWER LAKES TUE/WED WILL RESULT IN NORTHEASTERLY WINDS
INCREASING TO 20-30KT TUE NIGHT THRU WED. MIGHT SEE A FEW GALE FORCE
GUSTS WED OVER THE E HALF. EVEN THOUGH THE LOW CONTINUES TO MOVE E
THU...THE HIGH BUILDING TOWARD THE AREA FROM N WILL MAINTAIN A TIGHT
PRES GRADIENT...RESULTING IN CONTINUED 20-30KT WINDS WITH SOME
GALE FORCE GUSTS POSSIBLE OVER THE E HALF. WINDS WILL THEN VERY
SLOWLY DIMINISH FROM W TO E FRI/SAT AS THE HIGH PRES MOVES CLOSER...
BUT IT WILL PROBABLY BE SAT BEFORE WINDS DROP BLO 20KT ACROSS THE
ENTIRE LAKE. ALONG WITH THE PERIOD OF STRONGER WINDS MID
WEEK...FREEZING SPRAY IS ALSO EXPECTED.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...ROLFSON
LONG TERM...SRF
AVIATION...VOSS
MARINE...ROLFSON
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
1213 PM EST SUN FEB 24 2013
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 334 AM EST SUN FEB 24 2013
00Z RAOBS/LATEST WV IMAGERY AND RUC ANALYSIS SHOW CLOSED LO THAT HAS
BROUGHT SN/SHSN TO UPR MI THE LAST FEW DAYS MOVING SLOWLY TO THE E
AS UPR RDG AXIS EXTENDING FM HUDSON BAY INTO THE NRN PLAINS DRIFTS
SLOWLY TO THE E. COMBINATION OF LINGERING CYC NLY FLOW AND DEEP MSTR
SHOWN ON THE 00Z APX RAOB HAS ALLOWED SOME SHSN TO PERSIST OVER
MAINLY THE E HALF OF THE CWA UNDER POCKET OF H85/7 TEMPS AS LO AS
-11C/-17C...BUT THE CYC FLOW IS TENDING TO WEAKEN WITH SFC LO
SHIFTING TO THE E. IN FACT...THE WINDS AT STANNARD ROCK HAVE FALLEN
NEAR 5KTS EARLY THIS MRNG. 00Z RAOBS AT INL/YPL TO THE W/NW ALSO
SHOW A PRONOUNCED DRYING TREND ASSOCIATED WITH INCOMING RDG...WHICH
DROPPED THE INVRN BASE AS LO AS H9 AT YPL AT 00Z. 00Z H85 TEMPS
RANGE FM -11C AT GRB TO -6C AT INL AND -5C AT YPL. RECENT RADAR
TRENDS SHOW PERSISTENT HEAVIER SHSN THAT IMPACTED THE MQT AREA ARE
DIMINISHING WITH WEAKENING FLOW/SOME UPR DRYING UNDER DEEP LYR
QVECTOR DVGC/SUBSIDENCE LEFT IN THE WAKE OF SLOWLY DEPARTING CLOSED
LO. BUT SFC OBS/STLT IMAGERY SHOW LO CLDS LINGERING W INTO THE MN
ARROWHEAD. SKIES HAVE CLEARED OVER CNTRL MN UNDER SFC RDG AXIS.
FARTHER TO THE W...THERE IS A SHRTWV MOVING THRU SASKATCHEWAN.
PLENTY OF MID/HI CLDS ARE PRESENT TO THE E OF THIS DISTURBANCE...BUT
PCPN APPEARS LIMITED BY RATHER DRY LLVLS SHOWN ON THE 00Z BISMARCK
RAOB. ANOTHER MORE POTENT SHRTWV IS MOVING THRU THE SCENTRAL
ROCKIES. OTRW...THERE IS A LACK OF TRUE ARCTIC AIR OVER THE NRN
CONUS/SRN CANADA. IN FACT...THE 00Z H85 TEMP OF -11C AT GRB IS THE
LOWEST H85 TEMP IN CANADA S OF THE NW TERRITORIES AND NRN QUEBEC.
MAIN FCST CONCERNS IN THE SHORT TERM ARE FOCUSED ON CLD TRENDS/
IMPACT ON TEMPS.
TODAY...AS CLOSED LO SLIDES TO THE E...UPR RDG IS PROGGED TO BLD
OVER THE UPR LKS...RESULTING IN 12HR H5 HGT RISES UP TO 100M UNDER
INFLUENCE OF DEEP LYR QVECTOR DVGC/SUBSIDENCE. WITH SFC HI PRES RDG
AXIS FCST TO SHIFT INTO THE W HALF OF THE CWA BY 00Z MON...EXPECT
ANY LINGERING -SHSN TO END W-E. WITH LLVL NW FLOW PERSISTING THRU
THE DAY OVER THE E AHEAD OF INCOMING RDG AXIS...MIGHT EXPECT AT
LEAST SCT -SHSN TO PERSIST THERE. BUT FCST H85 TEMPS TO -8C TO -9C
IN THAT AREA /COMPARED TO LK WATER TEMPS 1 TO 2C/ BY 00Z AS WELL AS
DIFFLUENT NATURE OF THE INCRSG ACYC FLOW INDICATE THE ACTIVITY WL
END EVEN THERE IN THE AFTN. CLD TRENDS WL BE MORE DIFFICULT TO PIN
DOWN. AS THE SFC RDG AXIS ARRIVES...FCST SDNGS SHOWN INVRN BASE
SINKING TOWARD H9...WHICH MIGHT TRAP LINGERING LLVL MSTR AND RESULT
IN SC OVC. BUT WITH ACYC LLVL FLOW...SUSPECT SOME BREAKS IN THE CLDS
MAY DVLP OVER THE W NEAR THE WI BORDER LATER IN THE DAY...WHICH IS
CONSISTENT WITH THE CLRG OBSVD EARLY THIS MRNG CLOSER TO THE RDG
AXIS IN MN. AREAS OVER THE SCENTRAL FARTHER FM LK SUP INFLUENCE MAY
ALSO SEE SOME CLRG DESPITE RATHER WEAK WINDS/DOWNSLOPE IMPACT.
TNGT...THE SFC RDG AXIS IS PROGGED TO DRIFT SLOWLY TO THE E TNGT.
WITH WSHFT TO THE SW...EXPECT AT LEAST SOME BREAKS IN THE LINGERING
LO CLDS. WITH LGT WINDS...LOCATIONS THAT SEE SOME CLRG MIGHT SEE
TEMPS DROP SHARPLY. SO MAINTAINED FLAVOR OF GOING FCST SHOWING MIN
TEMPS DROPPING TOWARD THE LO END OF GUIDANCE. SOME HI CLDS AHEAD OF
SHRTWV MOVING ACRS SCENTRAL CANADA MAY MOVE INTO THE W LATE. SINCE
FOG HAS DVLPD UPSTREAM WHERE SKIES CLEARED IN MN...ADDED A MENTION
OF PATCHY FOG OVER THE INTERIOR AFTER MIDNGT.
.LONG TERM...(MONDAY THROUGH SATURDAY)
ISSUED AT 323 AM EST SUN FEB 24 2013
MUCH OF THE WEATHER FOR THE LONG TERM WILL BE DOMINATED BY THE
CURRENT 500MB LOW/TROUGH CENTERED OVER UTAH AND WESTERN COLORADO.
LOOK FOR THE LOW TO DEEPEN AS IT ROUNDS NORTHERN TEXAS ON
MONDAY...WITH A DISTINCT/WRAPPED UP SFC LOW DEVELOPING.
EXPECT A PROLONGED PERIOD OF WINDS FROM THE NORTHEAST QUADRANT
/360-90 DEGREES/ FROM TUESDAY THROUGH AT LEAST SATURDAY. IF
TEMPERATURES WERE COLDER WE WOULD BE LOOKING AT AN EXTENDED PERIOD
OF MODERATE LAKE EFFECT SNOW SHOWERS ACROSS MUCH OF THE AREA...AND
PARTICULAR NORTH CENTRAL UPPER MICHIGAN. HOWEVER...SURFACE TEMPS
NEAR FREEZING AND 850MB TEMPS -3C TO -5C TUESDAY THROUGH WEDNESDAY
WILL ONLY SUPPORT SOME LAKE ENHANCEMENT TO THE SNOW ROTATING AROUND
THE BACK SIDE OF THE SURFACE LOW FROM TUESDAY NIGHT ON.
THE GFS REMAINS STRONGEST WITH THE N/NNE WINDS THROUGH MUCH OF THE
PERIOD...WITH WINDS NEAR OR ABOVE 30KTS FROM WEDNESDAY AFTERNOON
THROUGH FRIDAY ACROSS LAKE SUPERIOR. THE ECMWF RANGES FROM 3-9KTS
LIGHTER WITH THE WINDS...THANKS TO THE OVERALL WEAKER LOW EJECTING
FROM THE SOUTHERN PLAINS AND ACROSS ILLINOIS TUESDAY...AND OVER
LOWER MICHIGAN WEDNESDAY. THIS IS THE MAIN DIFFERENCE...WHETHER THE
LOW ENDS UP BEING 992MB /23/18Z GFS/ OR 1000MB /23/12Z ECMWF/ AS IT
CROSSES INTO SOUTHERN LOWER MI WEDNESDAY MORNING. EVEN THROUGH THE
TRACK OF THE SFC LOW MAY BE A BIT ON THE QUICK SIDE OFF OF THE
ECMWF...THE CONSENSUS IS TO HAVE A WEAKER SYSTEM THAN WHAT IS
INDICATED BY THE GFS. THE 00Z RUN OF THE GFS CAME IN SLIGHTLY WEAKER
AND FARTHER S OF ITS 18Z RUN TRACK /APPROX 250MI SSE OF THE 18Z RUN
LOW AT 12Z THURSDAY/...WHICH ALSO DIMINISHED WIND SPEEDS ON THE
ORDER OF 2-5KTS. THE SLIGHTLY EASTWARD 23/12Z AND 24/00Z ECMWF RUNS
FOR THE LOW TRACK DO NOT LOOK LIKE SUCH AN OUTLIERS ANYMORE.
ANOTHER EXTENDED SFC TROUGH WILL LINGER ACROSS OUR AREA THROUGH
FRIDAY NIGHT...DESPITE STRONG HIGH PRESSURE PUSHING IN FROM THE
WEST. COLD AIR WILL REMAIN TRAPPED OVER NORTHEASTERN CANADA...WITH
-12C 850MB TEMPS OVER ONTARIO...-8 TO -10C ACROSS UPPER MICHIGAN
THURSDAY AFTERNOON THROUGH SATURDAY. WITH DRY HIGH PRESSURE
FILTERING IN AT THE SFC AND ALOFT...EXPECT DIMINISHING LAKE ENHANCED
PRECIPITATION NEAR LAKE SUPERIOR WITH ONLY MINOR ACCUMULATIONS.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z MONDAY AFTERNOON)
ISSUED AT 1212 PM EST SUN FEB 24 2013
VERY TRICKY AVIATION FORECAST FOR THE NEXT 24 HOURS...AS CONDITIONS
LARGELY DEPEND ON THE LOW CLOUDS TRAPPED UNDER THE INCREASING
INVERSION FROM A HIGH PRESSURE RIDGE MOVING ACROSS UPPER MICHIGAN.
EXPECT MVFR CONDITIONS AT ALL THREE SITES INTO THE EARLY
EVENING...ALTHOUGH SOME DRYING OVER WESTERN LAKE SUPERIOR COULD
LEAD TO A FEW BREAKS AT KCMX. THEN AS DIURNAL HEATING IS LOST...A
SLIGHTLY DRIER POCKET OF AIR IN SOUTH CENTRAL UPPER MI...WHERE CU
HAS DEVELOPED THIS AFTERNOON...WILL LIKELY SCATTER OR CLEAR
OUT. WITH WINDS BACKING TO THE SOUTHWEST...THINK THIS WILL
INFLUENCE KSAW AND HAVE CONTINUED MENTION OF SCATTERED CLOUDS. THE
MORE PERSISTENT MOISTURE/CLOUDS IN NORTH CENTRAL WI MAY KEEP
KIWD/KCMX CLOUDY THROUGH THE NIGHT...ALTHOUGH WITH INCREASING
SOUTHWEST FLOW ALOFT OVERNIGHT...COULD SEE KIWD SCATTER OUT LATE
TONIGHT OR MONDAY MORNING.
IF LOCATIONS SCATTER OUT...WOULD EXPECT TEMPERATURES TO QUICKLY
FALL AND FOG TO DEVELOP. HAVE CONTINUED MVFR VISIBILITIES DUE TO
UNCERTAINTY...BUT BASED ON OBS LAST NIGHT IN MINNESOTA...COULD SEE
IFR VISIBILITIES...ESPECIALLY AT KSAW/KIWD.
&&
.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 323 AM EST SUN FEB 24 2013
THE TROUGH OF LOW PRESSURE OVER EASTERN LAKE SUPERIOR WILL SLOWLY
DISSIPATE TODAY AS HIGH PRESSURE BUILDS ACROSS THE UPPER GREAT LAKES
THROUGH MONDAY NIGHT. EXPECT LOW PRESSURE OVER THE SOUTHERN PLAINS
SUNDAY NIGHT TO TRACK NORTHEAST ACROSS THE MID MISSISSIPPI VALLEY ON
TUESDAY...BEFORE MOVING THROUGH THE LOWER GREAT LAKES WEDNESDAY INTO
WEDNESDAY NIGHT...WITH A PROLONGED PERIOD OF N-NE WINDS FROM TUESDAY
THROUGH SATURDAY. THE LOW WILL MOVE EASTWARD THROUGH THURSDAY WHILE
LEAVING YET ANOTHER TROUGH OVER LAKE SUPERIOR AS HIGH PRESSURE MOVES
EAST THROUGH MANITOBA. THE NORTH WINDS ARE EXPECTED TO INCREASE
SLIGHTLY FOR THURSDAY WITH A FEW GALE FORCE GUSTS POSSIBLE.
OTHERWISE...WINDS SHOULD REMAIN BELOW 30KTS THROUGH THE PERIOD.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...KC
LONG TERM...KF
AVIATION...SRF
MARINE...KF
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
626 AM EST SUN FEB 24 2013
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 334 AM EST SUN FEB 24 2013
00Z RAOBS/LATEST WV IMAGERY AND RUC ANALYSIS SHOW CLOSED LO THAT HAS
BROUGHT SN/SHSN TO UPR MI THE LAST FEW DAYS MOVING SLOWLY TO THE E
AS UPR RDG AXIS EXTENDING FM HUDSON BAY INTO THE NRN PLAINS DRIFTS
SLOWLY TO THE E. COMBINATION OF LINGERING CYC NLY FLOW AND DEEP MSTR
SHOWN ON THE 00Z APX RAOB HAS ALLOWED SOME SHSN TO PERSIST OVER
MAINLY THE E HALF OF THE CWA UNDER POCKET OF H85/7 TEMPS AS LO AS
-11C/-17C...BUT THE CYC FLOW IS TENDING TO WEAKEN WITH SFC LO
SHIFTING TO THE E. IN FACT...THE WINDS AT STANNARD ROCK HAVE FALLEN
NEAR 5KTS EARLY THIS MRNG. 00Z RAOBS AT INL/YPL TO THE W/NW ALSO
SHOW A PRONOUNCED DRYING TREND ASSOCIATED WITH INCOMING RDG...WHICH
DROPPED THE INVRN BASE AS LO AS H9 AT YPL AT 00Z. 00Z H85 TEMPS
RANGE FM -11C AT GRB TO -6C AT INL AND -5C AT YPL. RECENT RADAR
TRENDS SHOW PERSISTENT HEAVIER SHSN THAT IMPACTED THE MQT AREA ARE
DIMINISHING WITH WEAKENING FLOW/SOME UPR DRYING UNDER DEEP LYR
QVECTOR DVGC/SUBSIDENCE LEFT IN THE WAKE OF SLOWLY DEPARTING CLOSED
LO. BUT SFC OBS/STLT IMAGERY SHOW LO CLDS LINGERING W INTO THE MN
ARROWHEAD. SKIES HAVE CLEARED OVER CNTRL MN UNDER SFC RDG AXIS.
FARTHER TO THE W...THERE IS A SHRTWV MOVING THRU SASKATCHEWAN.
PLENTY OF MID/HI CLDS ARE PRESENT TO THE E OF THIS DISTURBANCE...BUT
PCPN APPEARS LIMITED BY RATHER DRY LLVLS SHOWN ON THE 00Z BISMARCK
RAOB. ANOTHER MORE POTENT SHRTWV IS MOVING THRU THE SCENTRAL
ROCKIES. OTRW...THERE IS A LACK OF TRUE ARCTIC AIR OVER THE NRN
CONUS/SRN CANADA. IN FACT...THE 00Z H85 TEMP OF -11C AT GRB IS THE
LOWEST H85 TEMP IN CANADA S OF THE NW TERRITORIES AND NRN QUEBEC.
MAIN FCST CONCERNS IN THE SHORT TERM ARE FOCUSED ON CLD TRENDS/
IMPACT ON TEMPS.
TODAY...AS CLOSED LO SLIDES TO THE E...UPR RDG IS PROGGED TO BLD
OVER THE UPR LKS...RESULTING IN 12HR H5 HGT RISES UP TO 100M UNDER
INFLUENCE OF DEEP LYR QVECTOR DVGC/SUBSIDENCE. WITH SFC HI PRES RDG
AXIS FCST TO SHIFT INTO THE W HALF OF THE CWA BY 00Z MON...EXPECT
ANY LINGERING -SHSN TO END W-E. WITH LLVL NW FLOW PERSISTING THRU
THE DAY OVER THE E AHEAD OF INCOMING RDG AXIS...MIGHT EXPECT AT
LEAST SCT -SHSN TO PERSIST THERE. BUT FCST H85 TEMPS TO -8C TO -9C
IN THAT AREA /COMPARED TO LK WATER TEMPS 1 TO 2C/ BY 00Z AS WELL AS
DIFFLUENT NATURE OF THE INCRSG ACYC FLOW INDICATE THE ACTIVITY WL
END EVEN THERE IN THE AFTN. CLD TRENDS WL BE MORE DIFFICULT TO PIN
DOWN. AS THE SFC RDG AXIS ARRIVES...FCST SDNGS SHOWN INVRN BASE
SINKING TOWARD H9...WHICH MIGHT TRAP LINGERING LLVL MSTR AND RESULT
IN SC OVC. BUT WITH ACYC LLVL FLOW...SUSPECT SOME BREAKS IN THE CLDS
MAY DVLP OVER THE W NEAR THE WI BORDER LATER IN THE DAY...WHICH IS
CONSISTENT WITH THE CLRG OBSVD EARLY THIS MRNG CLOSER TO THE RDG
AXIS IN MN. AREAS OVER THE SCENTRAL FARTHER FM LK SUP INFLUENCE MAY
ALSO SEE SOME CLRG DESPITE RATHER WEAK WINDS/DOWNSLOPE IMPACT.
TNGT...THE SFC RDG AXIS IS PROGGED TO DRIFT SLOWLY TO THE E TNGT.
WITH WSHFT TO THE SW...EXPECT AT LEAST SOME BREAKS IN THE LINGERING
LO CLDS. WITH LGT WINDS...LOCATIONS THAT SEE SOME CLRG MIGHT SEE
TEMPS DROP SHARPLY. SO MAINTAINED FLAVOR OF GOING FCST SHOWING MIN
TEMPS DROPPING TOWARD THE LO END OF GUIDANCE. SOME HI CLDS AHEAD OF
SHRTWV MOVING ACRS SCENTRAL CANADA MAY MOVE INTO THE W LATE. SINCE
FOG HAS DVLPD UPSTREAM WHERE SKIES CLEARED IN MN...ADDED A MENTION
OF PATCHY FOG OVER THE INTERIOR AFTER MIDNGT.
.LONG TERM...(MONDAY THROUGH SATURDAY)
ISSUED AT 323 AM EST SUN FEB 24 2013
MUCH OF THE WEATHER FOR THE LONG TERM WILL BE DOMINATED BY THE
CURRENT 500MB LOW/TROUGH CENTERED OVER UTAH AND WESTERN COLORADO.
LOOK FOR THE LOW TO DEEPEN AS IT ROUNDS NORTHERN TEXAS ON
MONDAY...WITH A DISTINCT/WRAPPED UP SFC LOW DEVELOPING.
EXPECT A PROLONGED PERIOD OF WINDS FROM THE NORTHEAST QUADRANT
/360-90 DEGREES/ FROM TUESDAY THROUGH AT LEAST SATURDAY. IF
TEMPERATURES WERE COLDER WE WOULD BE LOOKING AT AN EXTENDED PERIOD
OF MODERATE LAKE EFFECT SNOW SHOWERS ACROSS MUCH OF THE AREA...AND
PARTICULAR NORTH CENTRAL UPPER MICHIGAN. HOWEVER...SURFACE TEMPS
NEAR FREEZING AND 850MB TEMPS -3C TO -5C TUESDAY THROUGH WEDNESDAY
WILL ONLY SUPPORT SOME LAKE ENHANCEMENT TO THE SNOW ROTATING AROUND
THE BACK SIDE OF THE SURFACE LOW FROM TUESDAY NIGHT ON.
THE GFS REMAINS STRONGEST WITH THE N/NNE WINDS THROUGH MUCH OF THE
PERIOD...WITH WINDS NEAR OR ABOVE 30KTS FROM WEDNESDAY AFTERNOON
THROUGH FRIDAY ACROSS LAKE SUPERIOR. THE ECMWF RANGES FROM 3-9KTS
LIGHTER WITH THE WINDS...THANKS TO THE OVERALL WEAKER LOW EJECTING
FROM THE SOUTHERN PLAINS AND ACROSS ILLINOIS TUESDAY...AND OVER
LOWER MICHIGAN WEDNESDAY. THIS IS THE MAIN DIFFERENCE...WHETHER THE
LOW ENDS UP BEING 992MB /23/18Z GFS/ OR 1000MB /23/12Z ECMWF/ AS IT
CROSSES INTO SOUTHERN LOWER MI WEDNESDAY MORNING. EVEN THROUGH THE
TRACK OF THE SFC LOW MAY BE A BIT ON THE QUICK SIDE OFF OF THE
ECMWF...THE CONSENSUS IS TO HAVE A WEAKER SYSTEM THAN WHAT IS
INDICATED BY THE GFS. THE 00Z RUN OF THE GFS CAME IN SLIGHTLY WEAKER
AND FARTHER S OF ITS 18Z RUN TRACK /APPROX 250MI SSE OF THE 18Z RUN
LOW AT 12Z THURSDAY/...WHICH ALSO DIMINISHED WIND SPEEDS ON THE
ORDER OF 2-5KTS. THE SLIGHTLY EASTWARD 23/12Z AND 24/00Z ECMWF RUNS
FOR THE LOW TRACK DO NOT LOOK LIKE SUCH AN OUTLIERS ANYMORE.
ANOTHER EXTENDED SFC TROUGH WILL LINGER ACROSS OUR AREA THROUGH
FRIDAY NIGHT...DESPITE STRONG HIGH PRESSURE PUSHING IN FROM THE
WEST. COLD AIR WILL REMAIN TRAPPED OVER NORTHEASTERN CANADA...WITH
-12C 850MB TEMPS OVER ONTARIO...-8 TO -10C ACROSS UPPER MICHIGAN
THURSDAY AFTERNOON THROUGH SATURDAY. WITH DRY HIGH PRESSURE
FILTERING IN AT THE SFC AND ALOFT...EXPECT DIMINISHING LAKE ENHANCED
PRECIPITATION NEAR LAKE SUPERIOR WITH ONLY MINOR ACCUMULATIONS.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z MONDAY MORNING)
ISSUED AT 625 AM EST SUN FEB 24 2013
EXPECT MVFR CIGS TO DOMINATE MOST OF TODAY AT ALL 3 TAF SITES WITH
LLVL MSTR TRAPPED BLO LOWERING INVRN BASE. THE ARRIVAL OF A HI PRES
RDG/LLVL ACYC FLOW MAY BRING SOME CLRG TO AT LEAST IWD AND SAW...BUT
MORE PERSISTENT UPSLOPE W WIND WL LIKELY MAINTAIN MVFR CONDITIONS AT
THE MORE EXPOSED CMX LOCATION. IF SKIES DO CLR AT IWD/SAW...FOG MAY
DVLP AT THOSE LOCATIONS TNGT AS HAPPENED IN MN UNDER THE RDG AXIS
EARLY THIS MRNG. IF THIS FOG DOES DVLP...IFR CONDITIONS ARE PSBL.
&&
.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 323 AM EST SUN FEB 24 2013
THE TROUGH OF LOW PRESSURE OVER EASTERN LAKE SUPERIOR WILL SLOWLY
DISSIPATE TODAY AS HIGH PRESSURE BUILDS ACROSS THE UPPER GREAT LAKES
THROUGH MONDAY NIGHT. EXPECT LOW PRESSURE OVER THE SOUTHERN PLAINS
SUNDAY NIGHT TO TRACK NORTHEAST ACROSS THE MID MISSISSIPPI VALLEY ON
TUESDAY...BEFORE MOVING THROUGH THE LOWER GREAT LAKES WEDNESDAY INTO
WEDNESDAY NIGHT...WITH A PROLONGED PERIOD OF N-NE WINDS FROM TUESDAY
THROUGH SATURDAY. THE LOW WILL MOVE EASTWARD THROUGH THURSDAY WHILE
LEAVING YET ANOTHER TROUGH OVER LAKE SUPERIOR AS HIGH PRESSURE MOVES
EAST THROUGH MANITOBA. THE NORTH WINDS ARE EXPECTED TO INCREASE
SLIGHTLY FOR THURSDAY WITH A FEW GALE FORCE GUSTS POSSIBLE.
OTHERWISE...WINDS SHOULD REMAIN BELOW 30KTS THROUGH THE PERIOD.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...KC
LONG TERM...KF
AVIATION...KC
MARINE...KF
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
335 AM EST SUN FEB 24 2013
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 334 AM EST SUN FEB 24 2013
00Z RAOBS/LATEST WV IMAGERY AND RUC ANALYSIS SHOW CLOSED LO THAT HAS
BROUGHT SN/SHSN TO UPR MI THE LAST FEW DAYS MOVING SLOWLY TO THE E
AS UPR RDG AXIS EXTENDING FM HUDSON BAY INTO THE NRN PLAINS DRIFTS
SLOWLY TO THE E. COMBINATION OF LINGERING CYC NLY FLOW AND DEEP MSTR
SHOWN ON THE 00Z APX RAOB HAS ALLOWED SOME SHSN TO PERSIST OVER
MAINLY THE E HALF OF THE CWA UNDER POCKET OF H85/7 TEMPS AS LO AS
-11C/-17C...BUT THE CYC FLOW IS TENDING TO WEAKEN WITH SFC LO
SHIFTING TO THE E. IN FACT...THE WINDS AT STANNARD ROCK HAVE FALLEN
NEAR 5KTS EARLY THIS MRNG. 00Z RAOBS AT INL/YPL TO THE W/NW ALSO
SHOW A PRONOUNCED DRYING TREND ASSOCIATED WITH INCOMING RDG...WHICH
DROPPED THE INVRN BASE AS LO AS H9 AT YPL AT 00Z. 00Z H85 TEMPS
RANGE FM -11C AT GRB TO -6C AT INL AND -5C AT YPL. RECENT RADAR
TRENDS SHOW PERSISTENT HEAVIER SHSN THAT IMPACTED THE MQT AREA ARE
DIMINISHING WITH WEAKENING FLOW/SOME UPR DRYING UNDER DEEP LYR
QVECTOR DVGC/SUBSIDENCE LEFT IN THE WAKE OF SLOWLY DEPARTING CLOSED
LO. BUT SFC OBS/STLT IMAGERY SHOW LO CLDS LINGERING W INTO THE MN
ARROWHEAD. SKIES HAVE CLEARED OVER CNTRL MN UNDER SFC RDG AXIS.
FARTHER TO THE W...THERE IS A SHRTWV MOVING THRU SASKATCHEWAN.
PLENTY OF MID/HI CLDS ARE PRESENT TO THE E OF THIS DISTURBANCE...BUT
PCPN APPEARS LIMITED BY RATHER DRY LLVLS SHOWN ON THE 00Z BISMARCK
RAOB. ANOTHER MORE POTENT SHRTWV IS MOVING THRU THE SCENTRAL
ROCKIES. OTRW...THERE IS A LACK OF TRUE ARCTIC AIR OVER THE NRN
CONUS/SRN CANADA. IN FACT...THE 00Z H85 TEMP OF -11C AT GRB IS THE
LOWEST H85 TEMP IN CANADA S OF THE NW TERRITORIES AND NRN QUEBEC.
MAIN FCST CONCERNS IN THE SHORT TERM ARE FOCUSED ON CLD TRENDS/
IMPACT ON TEMPS.
TODAY...AS CLOSED LO SLIDES TO THE E...UPR RDG IS PROGGED TO BLD
OVER THE UPR LKS...RESULTING IN 12HR H5 HGT RISES UP TO 100M UNDER
INFLUENCE OF DEEP LYR QVECTOR DVGC/SUBSIDENCE. WITH SFC HI PRES RDG
AXIS FCST TO SHIFT INTO THE W HALF OF THE CWA BY 00Z MON...EXPECT
ANY LINGERING -SHSN TO END W-E. WITH LLVL NW FLOW PERSISTING THRU
THE DAY OVER THE E AHEAD OF INCOMING RDG AXIS...MIGHT EXPECT AT
LEAST SCT -SHSN TO PERSIST THERE. BUT FCST H85 TEMPS TO -8C TO -9C
IN THAT AREA /COMPARED TO LK WATER TEMPS 1 TO 2C/ BY 00Z AS WELL AS
DIFFLUENT NATURE OF THE INCRSG ACYC FLOW INDICATE THE ACTIVITY WL
END EVEN THERE IN THE AFTN. CLD TRENDS WL BE MORE DIFFICULT TO PIN
DOWN. AS THE SFC RDG AXIS ARRIVES...FCST SDNGS SHOWN INVRN BASE
SINKING TOWARD H9...WHICH MIGHT TRAP LINGERING LLVL MSTR AND RESULT
IN SC OVC. BUT WITH ACYC LLVL FLOW...SUSPECT SOME BREAKS IN THE CLDS
MAY DVLP OVER THE W NEAR THE WI BORDER LATER IN THE DAY...WHICH IS
CONSISTENT WITH THE CLRG OBSVD EARLY THIS MRNG CLOSER TO THE RDG
AXIS IN MN. AREAS OVER THE SCENTRAL FARTHER FM LK SUP INFLUENCE MAY
ALSO SEE SOME CLRG DESPITE RATHER WEAK WINDS/DOWNSLOPE IMPACT.
TNGT...THE SFC RDG AXIS IS PROGGED TO DRIFT SLOWLY TO THE E TNGT.
WITH WSHFT TO THE SW...EXPECT AT LEAST SOME BREAKS IN THE LINGERING
LO CLDS. WITH LGT WINDS...LOCATIONS THAT SEE SOME CLRG MIGHT SEE
TEMPS DROP SHARPLY. SO MAINTAINED FLAVOR OF GOING FCST SHOWING MIN
TEMPS DROPPING TOWARD THE LO END OF GUIDANCE. SOME HI CLDS AHEAD OF
SHRTWV MOVING ACRS SCENTRAL CANADA MAY MOVE INTO THE W LATE. SINCE
FOG HAS DVLPD UPSTREAM WHERE SKIES CLEARED IN MN...ADDED A MENTION
OF PATCHY FOG OVER THE INTERIOR AFTER MIDNGT.
.LONG TERM...(MONDAY THROUGH SATURDAY)
ISSUED AT 323 AM EST SUN FEB 24 2013
MUCH OF THE WEATHER FOR THE LONG TERM WILL BE DOMINATED BY THE
CURRENT 500MB LOW/TROUGH CENTERED OVER UTAH AND WESTERN COLORADO.
LOOK FOR THE LOW TO DEEPEN AS IT ROUNDS NORTHERN TEXAS ON
MONDAY...WITH A DISTINCT/WRAPPED UP SFC LOW DEVELOPING.
EXPECT A PROLONGED PERIOD OF WINDS FROM THE NORTHEAST QUADRANT
/360-90 DEGREES/ FROM TUESDAY THROUGH AT LEAST SATURDAY. IF
TEMPERATURES WERE COLDER WE WOULD BE LOOKING AT AN EXTENDED PERIOD
OF MODERATE LAKE EFFECT SNOW SHOWERS ACROSS MUCH OF THE AREA...AND
PARTICULAR NORTH CENTRAL UPPER MICHIGAN. HOWEVER...SURFACE TEMPS
NEAR FREEZING AND 850MB TEMPS -3C TO -5C TUESDAY THROUGH WEDNESDAY
WILL ONLY SUPPORT SOME LAKE ENHANCEMENT TO THE SNOW ROTATING AROUND
THE BACK SIDE OF THE SURFACE LOW FROM TUESDAY NIGHT ON.
THE GFS REMAINS STRONGEST WITH THE N/NNE WINDS THROUGH MUCH OF THE
PERIOD...WITH WINDS NEAR OR ABOVE 30KTS FROM WEDNESDAY AFTERNOON
THROUGH FRIDAY ACROSS LAKE SUPERIOR. THE ECMWF RANGES FROM 3-9KTS
LIGHTER WITH THE WINDS...THANKS TO THE OVERALL WEAKER LOW EJECTING
FROM THE SOUTHERN PLAINS AND ACROSS ILLINOIS TUESDAY...AND OVER
LOWER MICHIGAN WEDNESDAY. THIS IS THE MAIN DIFFERENCE...WHETHER THE
LOW ENDS UP BEING 992MB /23/18Z GFS/ OR 1000MB /23/12Z ECMWF/ AS IT
CROSSES INTO SOUTHERN LOWER MI WEDNESDAY MORNING. EVEN THROUGH THE
TRACK OF THE SFC LOW MAY BE A BIT ON THE QUICK SIDE OFF OF THE
ECMWF...THE CONSENSUS IS TO HAVE A WEAKER SYSTEM THAN WHAT IS
INDICATED BY THE GFS. THE 00Z RUN OF THE GFS CAME IN SLIGHTLY WEAKER
AND FARTHER S OF ITS 18Z RUN TRACK /APPROX 250MI SSE OF THE 18Z RUN
LOW AT 12Z THURSDAY/...WHICH ALSO DIMINISHED WIND SPEEDS ON THE
ORDER OF 2-5KTS. THE SLIGHTLY EASTWARD 23/12Z AND 24/00Z ECMWF RUNS
FOR THE LOW TRACK DO NOT LOOK LIKE SUCH AN OUTLIERS ANYMORE.
ANOTHER EXTENDED SFC TROUGH WILL LINGER ACROSS OUR AREA THROUGH
FRIDAY NIGHT...DESPITE STRONG HIGH PRESSURE PUSHING IN FROM THE
WEST. COLD AIR WILL REMAIN TRAPPED OVER NORTHEASTERN CANADA...WITH
-12C 850MB TEMPS OVER ONTARIO...-8 TO -10C ACROSS UPPER MICHIGAN
THURSDAY AFTERNOON THROUGH SATURDAY. WITH DRY HIGH PRESSURE
FILTERING IN AT THE SFC AND ALOFT...EXPECT DIMINISHING LAKE ENHANCED
PRECIPITATION NEAR LAKE SUPERIOR WITH ONLY MINOR ACCUMULATIONS.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SUNDAY NIGHT)
ISSUED AT 1227 AM EST SUN FEB 24 2013
EXPECT LOW-END MVFR CEILINGS AT ALL SITES TO GRADUALLY IMPROVE TO
HIGHER-END MVFR CIGS BY SUNDAY AFTERNOON AS DEEPER MOISTURE DEPARTS
EAST WITH MOVEMENT OF LOW PRESSURE SYSTEM AND DRIER AIR FILTERS IN
FM WEST. ANY LINGERING LAKE ENHANCED SHSN AT KSAW SHOULD DISSIPATE
TO FLURRIES LATE TONIGHT AS DEEPER MOISTURE MOVES EAST AND LOW-LVL
CONVERGENCE WEAKENS.
&&
.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 323 AM EST SUN FEB 24 2013
THE TROUGH OF LOW PRESSURE OVER EASTERN LAKE SUPERIOR WILL SLOWLY
DISSIPATE TODAY AS HIGH PRESSURE BUILDS ACROSS THE UPPER GREAT LAKES
THROUGH MONDAY NIGHT. EXPECT LOW PRESSURE OVER THE SOUTHERN PLAINS
SUNDAY NIGHT TO TRACK NORTHEAST ACROSS THE MID MISSISSIPPI VALLEY ON
TUESDAY...BEFORE MOVING THROUGH THE LOWER GREAT LAKES WEDNESDAY INTO
WEDNESDAY NIGHT...WITH A PROLONGED PERIOD OF N-NE WINDS FROM TUESDAY
THROUGH SATURDAY. THE LOW WILL MOVE EASTWARD THROUGH THURSDAY WHILE
LEAVING YET ANOTHER TROUGH OVER LAKE SUPERIOR AS HIGH PRESSURE MOVES
EAST THROUGH MANITOBA. THE NORTH WINDS ARE EXPECTED TO INCREASE
SLIGHTLY FOR THURSDAY WITH A FEW GALE FORCE GUSTS POSSIBLE.
OTHERWISE...WINDS SHOULD REMAIN BELOW 30KTS THROUGH THE PERIOD.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...KC
LONG TERM...KF
AVIATION...VOSS
MARINE...KF
AREA FORECAST DISCUSSION
NWS DULUTH MN
801 PM CST MON FEB 25 2013
.UPDATE...
MAIN ISSUE IN THE SHORT TERM IS FOG POTENTIAL. CONCERN IS GROWING
THAT DENSE FOG WILL DEVELOP OVER PORTIONS OF OUR CWA. AT THIS
TIME WE ARE MOST CONCERNED WITH CASS COUNTY...EAST SOUTHEAST
TOWARD BURNETT COUNTY. TEMP-DEWPOINT SPREADS ARE LOW IN PARTS OF
THAT AREA...AND SKIES WERE CLEAR. WE`LL HAVE TO MONITOR ELSEWHERE
AS WELL. WE WILL WAIT ANOTHER HOUR OR SO...THEN DECIDE IF AND
WHERE WE WILL ISSUE A DENSE FOG ADVISORY.
&&
.PREV DISCUSSION... /ISSUED 550 PM CST MON FEB 25 2013/
AVIATION...00Z TAFS
SOME MVFR CEILINGS REMAINED OVER A PORTION OF NORTHWEST
WISCONSIN...AFFECTING KHYR/KASX/KPBH. SOME OF THE HIGH RES MODELS
SUGGEST THESE CEILINGS MAY DIMINISH SOME ON THE WEST EDGE...BUT
WILL REFORM OR ADVECT BACK TO THE WEST/NORTH AS THE LOW LEVEL FLOW
BECOMES EASTERLY. MORE LOWER CEILINGS WERE JUST SOUTHWEST OF
KBRD...AND THESE MAY REFORM LATER TONIGHT. THE RAP INDICATES THEY
WILL NOT...BUT CONFIDENCE THAT THESE CEILINGS WILL NOT REFORM IS
LOWER THAN AVERAGE.
FOG COULD BECOME AN ISSUE AS WELL OVERNIGHT WITH THE MILD TEMPS
MELTING SNOW TODAY. WE DID KEEP FOG IN ALL OF THE TAFS...AND
BROUGHT SOME IFR CEILINGS AS WELL. WE DID NOT GO TOO LOW ON VSBYS
YET...AND WILL WAIT UNTIL LATER TONIGHT AND SEE HOW THINGS DEVELOP
BEFORE MAKING ANY SIGNIFICANT CHANGES.
PREV DISCUSSION... /ISSUED 327 PM CST MON FEB 25 2013/
SHORT TERM...
THIS AFTERNOON THROUGH TUESDAY AFTERNOON...
QUIET WEATHER CONDITIONS ARE EXPECTED THROUGH THE SHORT TERM WITH
A WEAK RIDGE OF HIGH PRESSURE AT THE SFC IN PLACE ACROSS THE UPPER
MIDWEST. MAIN CONCERNS ARE FOCUSED AROUND TEMPERATURES AND THE
POTENTIAL FOR ANOTHER ROUND OF FOG TONIGHT...POSSIBLY DENSE IN
SOME LOCATIONS.
A WEAK UPPER TROUGH IS CURRENTLY MOVING THROUGH NRN MN/WRN LAKE
SUPERIOR THIS AFTERNOON AND DISSIPATING AS IT MOVES EWD. THERE WAS
A LINE OF LOW CLOUDS AND FLURRIES ASSOCIATED WITH A VERY WEAK SFC
TROUGH OVER NW MN THIS MORNING. HOWEVER...AS THE TROUGH HAS MOVED
EWD INTO THE DRIER AIR UNDER THE RIDGE...IT HAS WEAKENED
SUBSTANTIALLY THROUGH THE AFTERNOON. MOST OF THE CLOUD COVER HAS
DISSIPATED...AND LEFT ALMOST THE ENTIRE NORTHLAND UNDER MOSTLY
SUNNY SKIES THIS AFTERNOON. THERE IS ALSO AN AREA OF LOW/MID LEVEL
CLOUDS IN NW WI...THAT WILL ATTEMPT TO MOVE EWD...BUT BE REPLACED
QUICKLY BY ADDITIONAL CLOUDS MOVING IN FROM THE SOUTH ASSOCIATED
WITH THE LARGE WINTER STORM OVER THE CENTRAL PLAINS.
THE CLEAR SKIES TODAY HAVE LEAD TO TEMPERATURES REACHING INTO THE
MID TO UPPER 30S. ADDITIONAL TOP LAYER SNOW MELT LIKELY OCCURRED
ONCE AGAIN TODAY. SO...WITH THE CLEAR SKIES TONIGHT ALLOWING
TEMPERATURES TO FALL INTO THE TEENS...INCREASED LOW LEVEL
MOISTURE...LIGHT WINDS...AND A STRONG INVERSION ALOFT. THE THREAT
FOR FOG...POSSIBLY DENSE IN SOME LOCATIONS EXISTS AGAIN TONIGHT.
THE MOST FAVORABLE AREA FOR FOG APPEARS TO BE OVER NE MN...WITH
LIGHTER WINDS AND MOVE CLEARING. WHILE MUCH OF NW WI IS EXPECTED
TO REMAIN UNDER THE INFLUENCE OF MID/HIGH LEVEL CLOUDS AND
STRONGER MIXING.
TUESDAY IS EXPECTED TO BE ANOTHER PLEASANT DAY WITH MOSTLY SUNNY
TO PARTLY CLOUDY SKIES AFTER THE FOG BURNS OFF IN THE
MORNING...LIGHT WINDS AND TEMPERATURES IN THE MID TO UPPER
30S...POSSIBLY CLOSE TO 40 IN A FEW LOCATIONS.
LONG TERM...
TUESDAY NIGHT THROUGH MONDAY...
SOME LAKE EFFECT SNOW SHOWERS WILL LIKELY BE ONGOING ACROSS
NORTHERN PORTIONS OF WISCONSIN TUESDAY NIGHT AND INTO
WEDNESDAY...AS NORTHEAST WINDS BLOW ACROSS LAKE SUPERIOR FOR LONG
FETCH SNOW BANDS TO DEVELOP. AN INTENSE WINTER STORM WILL BE
ONGOING SOUTHEAST OF THE CWA WITH HIGH PRESSURE GENERALLY IN
CONTROL ACROSS OUR CWA. A TROUGH WILL LIKELY DEVELOP FROM THE LOW
PRESSURE SYSTEM MOVING THROUGH THE GREAT LAKES...WHICH MAY
ULTIMATELY BRING SOME BOUTS OF CLOUDINESS FOR THE REST OF THE WORK
WEEK...BUT IT WILL HAVE TO BATTLE UPPER LEVEL RIDGING AND HIGH
PRESSURE AS WELL. OVERALL IT LOOKS GENERALLY DRY FOR THE EXTENDED
TIME PERIOD AND WITH HIGHS IN THE UPPER 20S TO LOWER 30S. DAYTIME
MELTING MAY ALSO RESULT IN SOME FOG AT TIMES.
&&
.POINT TEMPS/POPS...
DLH 15 37 20 35 / 10 0 10 10
INL 12 38 14 34 / 0 0 0 10
BRD 12 35 18 35 / 10 0 0 0
HYR 16 37 20 36 / 10 10 20 20
ASX 20 34 23 34 / 10 0 20 30
&&
.DLH WATCHES/WARNINGS/ADVISORIES...
MN...NONE.
WI...NONE.
&&
$$
SHORT TERM...MELDE
LONG TERM....DAP
AREA FORECAST DISCUSSION
NWS DULUTH MN
550 PM CST MON FEB 25 2013
.AVIATION...00Z TAFS
SOME MVFR CEILINGS REMAINED OVER A PORTION OF NORTHWEST
WISCONSIN...AFFECTING KHYR/KASX/KPBH. SOME OF THE HIGH RES MODELS
SUGGEST THESE CEILINGS MAY DIMINISH SOME ON THE WEST EDGE...BUT
WILL REFORM OR ADVECT BACK TO THE WEST/NORTH AS THE LOW LEVEL FLOW
BECOMES EASTERLY. MORE LOWER CEILINGS WERE JUST SOUTHWEST OF
KBRD...AND THESE MAY REFORM LATER TONIGHT. THE RAP INDICATES THEY
WILL NOT...BUT CONFIDENCE THAT THESE CEILINGS WILL NOT REFORM IS
LOWER THAN AVERAGE.
FOG COULD BECOME AN ISSUE AS WELL OVERNIGHT WITH THE MILD TEMPS
MELTING SNOW TODAY. WE DID KEEP FOG IN ALL OF THE TAFS...AND
BROUGHT SOME IFR CEILINGS AS WELL. WE DID NOT GO TOO LOW ON VSBYS
YET...AND WILL WAIT UNTIL LATER TONIGHT AND SEE HOW THINGS DEVELOP
BEFORE MAKING ANY SIGNIFICANT CHANGES.
&&
.PREV DISCUSSION... /ISSUED 327 PM CST MON FEB 25 2013/
SHORT TERM...
THIS AFTERNOON THROUGH TUESDAY AFTERNOON...
QUIET WEATHER CONDITIONS ARE EXPECTED THROUGH THE SHORT TERM WITH
A WEAK RIDGE OF HIGH PRESSURE AT THE SFC IN PLACE ACROSS THE UPPER
MIDWEST. MAIN CONCERNS ARE FOCUSED AROUND TEMPERATURES AND THE
POTENTIAL FOR ANOTHER ROUND OF FOG TONIGHT...POSSIBLY DENSE IN
SOME LOCATIONS.
A WEAK UPPER TROUGH IS CURRENTLY MOVING THROUGH NRN MN/WRN LAKE
SUPERIOR THIS AFTERNOON AND DISSIPATING AS IT MOVES EWD. THERE WAS
A LINE OF LOW CLOUDS AND FLURRIES ASSOCIATED WITH A VERY WEAK SFC
TROUGH OVER NW MN THIS MORNING. HOWEVER...AS THE TROUGH HAS MOVED
EWD INTO THE DRIER AIR UNDER THE RIDGE...IT HAS WEAKENED
SUBSTANTIALLY THROUGH THE AFTERNOON. MOST OF THE CLOUD COVER HAS
DISSIPATED...AND LEFT ALMOST THE ENTIRE NORTHLAND UNDER MOSTLY
SUNNY SKIES THIS AFTERNOON. THERE IS ALSO AN AREA OF LOW/MID LEVEL
CLOUDS IN NW WI...THAT WILL ATTEMPT TO MOVE EWD...BUT BE REPLACED
QUICKLY BY ADDITIONAL CLOUDS MOVING IN FROM THE SOUTH ASSOCIATED
WITH THE LARGE WINTER STORM OVER THE CENTRAL PLAINS.
THE CLEAR SKIES TODAY HAVE LEAD TO TEMPERATURES REACHING INTO THE
MID TO UPPER 30S. ADDITIONAL TOP LAYER SNOW MELT LIKELY OCCURRED
ONCE AGAIN TODAY. SO...WITH THE CLEAR SKIES TONIGHT ALLOWING
TEMPERATURES TO FALL INTO THE TEENS...INCREASED LOW LEVEL
MOISTURE...LIGHT WINDS...AND A STRONG INVERSION ALOFT. THE THREAT
FOR FOG...POSSIBLY DENSE IN SOME LOCATIONS EXISTS AGAIN TONIGHT.
THE MOST FAVORABLE AREA FOR FOG APPEARS TO BE OVER NE MN...WITH
LIGHTER WINDS AND MOVE CLEARING. WHILE MUCH OF NW WI IS EXPECTED
TO REMAIN UNDER THE INFLUENCE OF MID/HIGH LEVEL CLOUDS AND
STRONGER MIXING.
TUESDAY IS EXPECTED TO BE ANOTHER PLEASANT DAY WITH MOSTLY SUNNY
TO PARTLY CLOUDY SKIES AFTER THE FOG BURNS OFF IN THE
MORNING...LIGHT WINDS AND TEMPERATURES IN THE MID TO UPPER
30S...POSSIBLY CLOSE TO 40 IN A FEW LOCATIONS.
LONG TERM...
TUESDAY NIGHT THROUGH MONDAY...
SOME LAKE EFFECT SNOW SHOWERS WILL LIKELY BE ONGOING ACROSS
NORTHERN PORTIONS OF WISCONSIN TUESDAY NIGHT AND INTO
WEDNESDAY...AS NORTHEAST WINDS BLOW ACROSS LAKE SUPERIOR FOR LONG
FETCH SNOW BANDS TO DEVELOP. AN INTENSE WINTER STORM WILL BE
ONGOING SOUTHEAST OF THE CWA WITH HIGH PRESSURE GENERALLY IN
CONTROL ACROSS OUR CWA. A TROUGH WILL LIKELY DEVELOP FROM THE LOW
PRESSURE SYSTEM MOVING THROUGH THE GREAT LAKES...WHICH MAY
ULTIMATELY BRING SOME BOUTS OF CLOUDINESS FOR THE REST OF THE WORK
WEEK...BUT IT WILL HAVE TO BATTLE UPPER LEVEL RIDGING AND HIGH
PRESSURE AS WELL. OVERALL IT LOOKS GENERALLY DRY FOR THE EXTENDED
TIME PERIOD AND WITH HIGHS IN THE UPPER 20S TO LOWER 30S. DAYTIME
MELTING MAY ALSO RESULT IN SOME FOG AT TIMES.
&&
.POINT TEMPS/POPS...
DLH 15 37 20 35 / 10 0 10 10
INL 12 38 14 34 / 0 0 0 10
BRD 12 35 18 35 / 10 0 0 0
HYR 16 37 20 36 / 10 10 20 20
ASX 20 34 23 34 / 10 0 20 30
&&
.DLH WATCHES/WARNINGS/ADVISORIES...
MN...NONE.
WI...NONE.
&&
$$
SHORT TERM...TENTINGER
LONG TERM....DAP
AVIATION...MELDE
AREA FORECAST DISCUSSION
NWS TWIN CITIES/CHANHASSEN MN
1127 AM CST SUN FEB 24 2013
.DISCUSSION...
MORE AND MORE...THE UPCOMING WEEK IS LOOKING DRY...AS MODELS
CONTINUE TO TREND THE BIG MIDWEEK WINTER STORM SOUTH AND EAST OF THE
MPX AREA. OTHERWISE...ONLY CONCERN TONIGHT AND AGAIN MONDAY NIGHT
WILL BE FOR REPEAT PERFORMANCES OF DENSE FOG.
OUT THE GATE THIS MORNING...MOIST BOUNDARY LAYER HAS COMBINED WITH
CLEAR SKIES AND LIGHT WINDS UNDER A SFC RIDGE ACROSS THE WRN HALF OF
MN TO GET SOME FAIRLY WIDESPREAD FOG GOING. PRETTY SOLID AREA OF 1/2
MILE OR LESS VIS FROM WEST CENTRAL UP THROUGH NW MN. FROM THE TWIN
CITIES ON EAST...STUBBORN CLOUD LAYER HAS KEPT FOG FROM FORMING. AS
FOR CURRENT ADVY...WILL TRIM COUNTIES UNDER THE INFLUENCE OF CLOUDS
OUT OF WHILE LEAVING THE REST IN PLACE...THOUGH MAY EXPAND IT ACROSS
THE REST OF SOUTH CENTRAL MN GIVEN DENSE FOG OBS AT FAIRMONT AND ST.
JAMES. BASED ON VIS FORECASTS FROM HRRR AND HOPWRF ENSEMBLE...NOT
EXPECTING ANY SIGNIFICANT IMPROVEMENTS UNTIL AFTER 15Z. IN
FACT...WHERE FOG IS MOST DENSE AROUND THE AXN AREA...MAY NOT BE
UNTIL CLOSER TO 18Z BEFORE SIGNIFICANT IMPROVEMENTS ARE MADE. THE
SLOW VIS RECOVERY IS SUPPORTED PHYSICALLY BY THE FACT THAT WE STILL
HAVE A SOMEWHAT SHALLOW LATE FEBRUARY SOLAR ANGLE AND VIRTUALLY NO
WIND IS EXPECTED WITHIN THE LOWEST 7K FT OF THE ATMO TODAY TO HELP
MIX THINGS OUT.
AS FOR FOG POTENTIAL AFTER TONIGHT...THE MPX AREA WILL REMAIN UNDER
A COL IN THE PRESSURE FIELD THROUGH MONDAY NIGHT...RESULTING IN WEAK
WINDS AND THEREFORE WEAK MECHANICAL MIXING. THE BIG QUESTION MARK
THE NEXT TWO NIGHTS WILL BE MID/UPPER LEVEL CLOUDS. TONIGHT LOOKS TO
OFFER A DECENT AMOUNT OF UPPER CLOUDS AS COMPLEX UPPER TROUGH
CURRENTLY OVER THE HIGH PLAINS MOVES OVERHEAD. SATELLITE IMAGERY
SHOWS PLENTY OF CLOUD COVER ASSOCIATED WITH THIS TROUGH AND AS THIS
PUSHES EAST DURING THE DAY...THIS SHOULD RESULT IN PLENTY OF
MID/UPPER CLOUDS TONIGHT. MONDAY NIGHT MAY FEATURE LESS CLOUD COVER
AS THE NRN STREAM WAVE SHEARS OUT. FORECAST SOUNDINGS BOTH NIGHTS
SHOW PLENTY OF LOW LEVEL MOISTURE BEING IN PLACE UNDER THE SFC RIDGE
TO SUPPORT FOG FORMATION...SO LONG AS THERE IS MINIMAL CLOUD COVER.
WITH UNCERTAINTIES IN CLOUD COVER BOTH NIGHTS...DID NOT MENTION ANY
FOG IN THE FORECAST...BUT THIS IS SOMETHING THAT WILL NEED TO BE
WATCHED CLOSELY.
WHEN IT COMES TO PRECIPITATION...NOW DOWN TO BASICALLY ONE
MODEL...THE GEM...THAT IS STILL BRINGING PRECIP TO THE AREA MID WEEK
IN ASSOCIATION WITH THE DEEP TROUGH NOW OVER THE 4-CORNERS. MODELS
ALL PRETTY SIMILAR WITH TAKING THIS UPPER LOW FROM NEW MEXICO TODAY
OVER TO THE LAKE ERIE REGION BY WEDNESDAY. THIS WILL BE QUITE THE
IMPRESSIVE SYSTEM...WITH H5 HEIGHT FALLS ON THE ORDER OF 200M AND A
WELL DEFINED H7 LOW. HEAVY SNOW SWATH STILL LOOKS LIKE A GOOD BET
FROM THE NE TX PANHANDLE UP INTO THE CHICAGO METRO AREA AND MID
MICHIGAN. FOR THE MPX AREA...WE WILL BE BATTLING RATHER STRONG DRY
AIR ADVECTION AND SUBSIDENCE ON THE NORTH SIDE OF THE SYSTEM. ONLY
REAL HOPE FOR PRECIP IN THE MPX AREA LOOKS TO COME TUESDAY NIGHT
INTO WEDNESDAY AS SFC LOW IS TRACKING FROM SRN IL TOWARD NRN OH. THE
QUESTION HERE IS HOW FAR NW DOES EXPANSIVE WRAP-AROUND PRECIP SHIELD
MAKE IT. AT THIS POINT...ONLY THE WRN OUTLIER GEM IS SHOWING PRECIP
ACROSS THE MPX CWA...WITH EVEN THE 24.03 SREF TRENDING SE WITH
PRECIP...KEEPING EVEN ERN AREAS WEST OF THE PRECIP. IF THIS TREND
CONTINUES...FUTURE SHIFTS COULD PROBABLY START PULLING OUT PRECIP
MENTION COMPLETELY. AS FOR WIND AND BLOWING SNOW POTENTIAL MID
WEEK...STILL EXPECT SPEEDS TO PICK UP TUESDAY THROUGH THURSDAY...BUT
WITH THE MAIN SFC LOW GOING AS FAR SOUTH AS IT IS...NOT EXPECTING
WINDS STRONG ENOUGH TO LEAD TO SIGNIFICANT ISSUES. LIKE TO SEE GUST
POTENTIAL OVER 30 MPH TO START SEEING SIGNIFICANT BLOWING SNOW
ISSUES...AND FORECAST SOUNDINGS FROM THE GFS KEEP EVERYTHING IN THE
20S.
FINALLY...WITH TEMPERATURES...NOT EXPECTING MUCH VARIATION OVER THE
NEXT WEEK AS 925-850 TEMPS LOOK TO STAY MORE OR LESS UNCHANGED. THIS
MEANS WE SHOULD CONTINUE TO SEE LOWER ALBEDO AREAS ACROSS CENTRAL
AND EAST CENTRAL MN INTO WRN WI WITH HIGHS MAINLY IN THE 30S...WHILE
HIGHER ALBEDO AREAS FROM WEST CENTRAL INTO SOUTH CENTRAL MN SEE HIGH
MAINLY SEE IN THE 20S. FOR LOWS...FOR THE NEXT COUPLE OF NIGHTS WITH
THE COL IN THE PRESSURE FIELD REMAINING OVERHEAD...THIS WILL LEAD TO
THE POTENTIAL FOR LOWS AROUND ZERO WHERE EVER A FEW HOURS OF
CLEARING CAN BE SEEN. OTHERWISE...LOWS WILL REMAIN ON THE MILD END
UNDER THE INFLUENCE OF CLOUDS...REMAINING UP IN THE TEENS AND 20S.
&&
.AVIATION.../18Z TAF ISSUANCE/
VERY SIMILAR CONCERNS WITH THIS TAF PERIOD AS LOW LEVEL WINDS AND
MIXING REMAINS NEARLY NON-EXISTENT UNTIL AFT 00Z/26...OR UNTIL THE
MAIN STORM SYSTEM THAT IS EXPECTED TO DEVELOP ACROSS THE
PLAINS...BEGINS TO INTERACT WITH THE SFC RIDGE OVER OUR REGION.
THIS WOULD LEAD TO A MORE MORE PREVAILING E/NE WIND FLOW MONDAY
NIGHT/TUE. IN THE SHORT TERM...AND MAINLY THE AFFECTS OF CLOUD
COVER AND LITTLE MIXING...CONFIDENCE REMAINS LOW ON THE
REDEVELOPMENT OF FG/BR OVERNIGHT. WILL CONTINUE THE SAME
PERSISTENT TREND WITH LOW CLDS AND VERY LOW VSBYS DEVELOPING
OVERNIGHT. BUT WITH THE AMT OF CLOUD COVER SPREADING E/NE ACROSS
THE UPPER MIDWEST...THIS WILL PLAY HAVOC ON ANY RADIATIONAL FG/BR
AFFECTS AND MORE MVFR/IFR VSBYS AND LITTLE IN THE WAY OF LOW CIGS.
THIS WAS THE CASE IN WC WI OVERNIGHT WHERE THE CLDS KEPT THE
AFFECTS OF RADIATIONAL COOLING AT A MINIMAL.
KMSP...
BEST SCENARIO FOR THIS TAF PERIOD IS PERSISTENCE AS MORE CLOUDS
SPREADING NE ACROSS IA...WILL BEGIN TO AFFECT SC/SE/EC MN BY THE
LATE AFTN/EARLY EVENING TIME PERIOD. THESE CLOUDS ARE WELL DEFINED
IN THE LATEST 3.9U SATELLITE IMAGERY ACROSS NW IA...WITH A BLEND
OF HIGHER CLDS/BR ACROSS THE REST OF THE FA. BEST TIME FRAME FOR
THE MVFR CIGS TO SPREAD INTO EC MN WILL BEGIN AFT 22-23Z THIS
AFTN. THIS WILL LIKELY HINDER THE AFFECTS OF RADIATIONAL COOLING
AND THE FORMATION OF BR/FG OVERNIGHT. HOWEVER...THIS CLOUDS ARE
EXPECTED TO DISSIPATE BY 6Z...WHICH WILL LEAD TO LESS CLOUD COVER
AND MORE IN THE WAY OF FG/BR FORMATION. THE WORSE CONDS WILL
LIKELY BE THE TYPICAL 09-15Z TIME FRAME WITH THE POSSIBILITY OF
LIFR CIGS/VSBYS. A GENERAL TREND OF CIGS SLOWLY RISING TO MVFR BY
18Z...AND POSSIBLY ABV 1.7K BY THE EARLY AFTN. WINDS WILL BE
NEARLY CALM...WITH A SLIGHT TREND OF A SE COMPONENT THIS
AFTN...AND MORE OF A SW COMPONENT MONDAY.
/OUTLOOK FOR KMSP/
TUE...MVFR WITH IFR AND -SN POSSIBLE. WINDS N 10G15KTS.
WED...MVFR POSSIBLE IN THE MORNING...OTHERWISE VFR. WINDS NNE 10KTS.
THU...MVFR/VFR CIGS WITH -SN POSSIBLE. NW WIND 10 KTS. ..JLT..
&&
.MPX WATCHES/WARNINGS/ADVISORIES...
MN...NONE.
WI...NONE.
&&
$$
MPG/JLT
AREA FORECAST DISCUSSION
NWS TWIN CITIES/CHANHASSEN MN
716 AM CST SUN FEB 24 2013
.UPDATE...
UPDATED TO INCLUDE 12Z AVIATION DISCUSSION BELOW.
&&
.DISCUSSION...
MORE AND MORE...THE UPCOMING WEEK IS LOOKING DRY...AS MODELS
CONTINUE TO TREND THE BIG MIDWEEK WINTER STORM SOUTH AND EAST OF THE
MPX AREA. OTHERWISE...ONLY CONCERN TONIGHT AND AGAIN MONDAY NIGHT
WILL BE FOR REPEAT PERFORMANCES OF DENSE FOG.
OUT THE GATE THIS MORNING...MOIST BOUNDARY LAYER HAS COMBINED WITH
CLEAR SKIES AND LIGHT WINDS UNDER A SFC RIDGE ACROSS THE WRN HALF OF
MN TO GET SOME FAIRLY WIDESPREAD FOG GOING. PRETTY SOLID AREA OF 1/2
MILE OR LESS VIS FROM WEST CENTRAL UP THROUGH NW MN. FROM THE TWIN
CITIES ON EAST...STUBBORN CLOUD LAYER HAS KEPT FOG FROM FORMING. AS
FOR CURRENT ADVY...WILL TRIM COUNTIES UNDER THE INFLUENCE OF CLOUDS
OUT OF WHILE LEAVING THE REST IN PLACE...THOUGH MAY EXPAND IT ACROSS
THE REST OF SOUTH CENTRAL MN GIVEN DENSE FOG OBS AT FAIRMONT AND ST.
JAMES. BASED ON VIS FORECASTS FROM HRRR AND HOPWRF ENSEMBLE...NOT
EXPECTING ANY SIGNIFICANT IMPROVEMENTS UNTIL AFTER 15Z. IN
FACT...WHERE FOG IS MOST DENSE AROUND THE AXN AREA...MAY NOT BE
UNTIL CLOSER TO 18Z BEFORE SIGNIFICANT IMPROVEMENTS ARE MADE. THE
SLOW VIS RECOVERY IS SUPPORTED PHYSICALLY BY THE FACT THAT WE STILL
HAVE A SOMEWHAT SHALLOW LATE FEBRUARY SOLAR ANGLE AND VIRTUALLY NO
WIND IS EXPECTED WITHIN THE LOWEST 7K FT OF THE ATMO TODAY TO HELP
MIX THINGS OUT.
AS FOR FOG POTENTIAL AFTER TONIGHT...THE MPX AREA WILL REMAIN UNDER
A COL IN THE PRESSURE FIELD THROUGH MONDAY NIGHT...RESULTING IN WEAK
WINDS AND THEREFORE WEAK MECHANICAL MIXING. THE BIG QUESTION MARK
THE NEXT TWO NIGHTS WILL BE MID/UPPER LEVEL CLOUDS. TONIGHT LOOKS TO
OFFER A DECENT AMOUNT OF UPPER CLOUDS AS COMPLEX UPPER TROUGH
CURRENTLY OVER THE HIGH PLAINS MOVES OVERHEAD. SATELLITE IMAGERY
SHOWS PLENTY OF CLOUD COVER ASSOCIATED WITH THIS TROUGH AND AS THIS
PUSHES EAST DURING THE DAY...THIS SHOULD RESULT IN PLENTY OF
MID/UPPER CLOUDS TONIGHT. MONDAY NIGHT MAY FEATURE LESS CLOUD COVER
AS THE NRN STREAM WAVE SHEARS OUT. FORECAST SOUNDINGS BOTH NIGHTS
SHOW PLENTY OF LOW LEVEL MOISTURE BEING IN PLACE UNDER THE SFC RIDGE
TO SUPPORT FOG FORMATION...SO LONG AS THERE IS MINIMAL CLOUD COVER.
WITH UNCERTAINTIES IN CLOUD COVER BOTH NIGHTS...DID NOT MENTION ANY
FOG IN THE FORECAST...BUT THIS IS SOMETHING THAT WILL NEED TO BE
WATCHED CLOSELY.
WHEN IT COMES TO PRECIPITATION...NOW DOWN TO BASICALLY ONE
MODEL...THE GEM...THAT IS STILL BRINGING PRECIP TO THE AREA MID WEEK
IN ASSOCIATION WITH THE DEEP TROUGH NOW OVER THE 4-CORNERS. MODELS
ALL PRETTY SIMILAR WITH TAKING THIS UPPER LOW FROM NEW MEXICO TODAY
OVER TO THE LAKE ERIE REGION BY WEDNESDAY. THIS WILL BE QUITE THE
IMPRESSIVE SYSTEM...WITH H5 HEIGHT FALLS ON THE ORDER OF 200M AND A
WELL DEFINED H7 LOW. HEAVY SNOW SWATH STILL LOOKS LIKE A GOOD BET
FROM THE NE TX PANHANDLE UP INTO THE CHICAGO METRO AREA AND MID
MICHIGAN. FOR THE MPX AREA...WE WILL BE BATTLING RATHER STRONG DRY
AIR ADVECTION AND SUBSIDENCE ON THE NORTH SIDE OF THE SYSTEM. ONLY
REAL HOPE FOR PRECIP IN THE MPX AREA LOOKS TO COME TUESDAY NIGHT
INTO WEDNESDAY AS SFC LOW IS TRACKING FROM SRN IL TOWARD NRN OH. THE
QUESTION HERE IS HOW FAR NW DOES EXPANSIVE WRAP-AROUND PRECIP SHIELD
MAKE IT. AT THIS POINT...ONLY THE WRN OUTLIER GEM IS SHOWING PRECIP
ACROSS THE MPX CWA...WITH EVEN THE 24.03 SREF TRENDING SE WITH
PRECIP...KEEPING EVEN ERN AREAS WEST OF THE PRECIP. IF THIS TREND
CONTINUES...FUTURE SHIFTS COULD PROBABLY START PULLING OUT PRECIP
MENTION COMPLETELY. AS FOR WIND AND BLOWING SNOW POTENTIAL MID
WEEK...STILL EXPECT SPEEDS TO PICK UP TUESDAY THROUGH THURSDAY...BUT
WITH THE MAIN SFC LOW GOING AS FAR SOUTH AS IT IS...NOT EXPECTING
WINDS STRONG ENOUGH TO LEAD TO SIGNIFICANT ISSUES. LIKE TO SEE GUST
POTENTIAL OVER 30 MPH TO START SEEING SIGNIFICANT BLOWING SNOW
ISSUES...AND FORECAST SOUNDINGS FROM THE GFS KEEP EVERYTHING IN THE
20S.
FINALLY...WITH TEMPERATURES...NOT EXPECTING MUCH VARIATION OVER THE
NEXT WEEK AS 925-850 TEMPS LOOK TO STAY MORE OR LESS UNCHANGED. THIS
MEANS WE SHOULD CONTINUE TO SEE LOWER ALBEDO AREAS ACROSS CENTRAL
AND EAST CENTRAL MN INTO WRN WI WITH HIGHS MAINLY IN THE 30S...WHILE
HIGHER ALBEDO AREAS FROM WEST CENTRAL INTO SOUTH CENTRAL MN SEE HIGH
MAINLY SEE IN THE 20S. FOR LOWS...FOR THE NEXT COUPLE OF NIGHTS WITH
THE COL IN THE PRESSURE FIELD REMAINING OVERHEAD...THIS WILL LEAD TO
THE POTENTIAL FOR LOWS AROUND ZERO WHERE EVER A FEW HOURS OF
CLEARING CAN BE SEEN. OTHERWISE...LOWS WILL REMAIN ON THE MILD END
UNDER THE INFLUENCE OF CLOUDS...REMAINING UP IN THE TEENS AND 20S.
&&
.AVIATION.../12Z TAF ISSUANCE/
HIGH PRES TO SLIDE ACRS THE REGION THRU THE NEXT 24 HRS...BUT
RELATIVELY DEEP MOISTURE WITH E WINDS ALOFT WILL HELP KEEP FOG/LOW
CLOUDS IN PLACE THRU THE FIRST HALF OF THE DAY TDA. MOST OF THE
FOG THIS MRNG IS IN WRN-CENTRAL MN WITH THE LOW STRATUS IN ERN MN
INTO WRN WI...BUT CONDS WILL IMPROVE SLOWLY THRU THE MRNG HOURS.
SEVERAL HRS OF VFR CONDS XPCTD THIS AFTN INTO THIS EVE. HOWEVER...
WITH LGT WINDS AGAIN TNGT...WILL AGAIN LOOK FOR MVFR-IFR CONDS DUE
TO FOG/LOW STRATUS SETTLING IN. NO PRECIP ISSUES AND NO WINDS OVR
5-6 KT XPCTD.
KMSP...MVFR CONDS...MAINLY DUE TO VSBY...TO START ALTHOUGH MUCH
LOWER CONDS PLAGUE SMALLER TERMINALS ALL ARND MSP. HOWEVER... HAVE
BEEN OBSERVING IMPROVEMENTS AT ALL SITES SO AM NOT THINKING MSP
WOULD DROP INTO IFR FOR ANY GREAT LENGTH...IF AT ALL...THIS MRNG.
VFR CONDS THEN XPCTD FOR MUCH OF THE DAY INTO THIS EVENING. CONDS
THEN DROP AGAIN TNGT...STARTING ARND MIDNIGHT...HITTING MVFR RANGE
WITH A FEW OBS OF IFR POSSIBLE.
/OUTLOOK FOR KMSP/
MON...MVFR POSSIBLE IN THE MORNING...OTHERWISE VFR. WINDS ENE 5KTS.
TUE...MVFR WITH IFR AND -SN POSSIBLE. WINDS N 10G15KTS.
WED...MVFR POSSIBLE IN THE MORNING...OTHERWISE VFR. WINDS NNE 10KTS.
&&
.MPX WATCHES/WARNINGS/ADVISORIES...
MN...FREEZING FOG ADVISORY UNTIL 9 AM CST THIS MORNING FOR BLUE EARTH-
BROWN-CARVER-CHIPPEWA-DOUGLAS-FARIBAULT-FREEBORN-KANDIYOHI-
LE SUEUR-MARTIN-MCLEOD-MEEKER-NICOLLET-POPE-RENVILLE-RICE-
SCOTT-SIBLEY-STEARNS-STEELE-STEVENS-SWIFT-TODD-WASECA-
WATONWAN-WRIGHT.
WI...NONE.
&&
$$
JPC
AREA FORECAST DISCUSSION
NWS TWIN CITIES/CHANHASSEN MN
355 AM CST SUN FEB 24 2013
.DISCUSSION...
MORE AND MORE...THE UPCOMING WEEK IS LOOKING DRY...AS MODELS
CONTINUE TO TREND THE BIG MIDWEEK WINTER STORM SOUTH AND EAST OF THE
MPX AREA. OTHERWISE...ONLY CONCERN TONIGHT AND AGAIN MONDAY NIGHT
WILL BE FOR REPEAT PERFORMANCES OF DENSE FOG.
OUT THE GATE THIS MORNING...MOIST BOUNDARY LAYER HAS COMBINED WITH
CLEAR SKIES AND LIGHT WINDS UNDER A SFC RIDGE ACROSS THE WRN HALF OF
MN TO GET SOME FAIRLY WIDESPREAD FOG GOING. PRETTY SOLID AREA OF 1/2
MILE OR LESS VIS FROM WEST CENTRAL UP THROUGH NW MN. FROM THE TWIN
CITIES ON EAST...STUBBORN CLOUD LAYER HAS KEPT FOG FROM FORMING. AS
FOR CURRENT ADVY...WILL TRIM COUNTIES UNDER THE INFLUENCE OF CLOUDS
OUT OF WHILE LEAVING THE REST IN PLACE...THOUGH MAY EXPAND IT ACROSS
THE REST OF SOUTH CENTRAL MN GIVEN DENSE FOG OBS AT FAIRMONT AND ST.
JAMES. BASED ON VIS FORECASTS FROM HRRR AND HOPWRF ENSEMBLE...NOT
EXPECTING ANY SIGNIFICANT IMPROVEMENTS UNTIL AFTER 15Z. IN
FACT...WHERE FOG IS MOST DENSE AROUND THE AXN AREA...MAY NOT BE
UNTIL CLOSER TO 18Z BEFORE SIGNIFICANT IMPROVEMENTS ARE MADE. THE
SLOW VIS RECOVERY IS SUPPORTED PHYSICALLY BY THE FACT THAT WE STILL
HAVE A SOMEWHAT SHALLOW LATE FEBRUARY SOLAR ANGLE AND VIRTUALLY NO
WIND IS EXPECTED WITHIN THE LOWEST 7K FT OF THE ATMO TODAY TO HELP
MIX THINGS OUT.
AS FOR FOG POTENTIAL AFTER TONIGHT...THE MPX AREA WILL REMAIN UNDER
A COL IN THE PRESSURE FIELD THROUGH MONDAY NIGHT...RESULTING IN WEAK
WINDS AND THEREFORE WEAK MECHANICAL MIXING. THE BIG QUESTION MARK
THE NEXT TWO NIGHTS WILL BE MID/UPPER LEVEL CLOUDS. TONIGHT LOOKS TO
OFFER A DECENT AMOUNT OF UPPER CLOUDS AS COMPLEX UPPER TROUGH
CURRENTLY OVER THE HIGH PLAINS MOVES OVERHEAD. SATELLITE IMAGERY
SHOWS PLENTY OF CLOUD COVER ASSOCIATED WITH THIS TROUGH AND AS THIS
PUSHES EAST DURING THE DAY...THIS SHOULD RESULT IN PLENTY OF
MID/UPPER CLOUDS TONIGHT. MONDAY NIGHT MAY FEATURE LESS CLOUD COVER
AS THE NRN STREAM WAVE SHEARS OUT. FORECAST SOUNDINGS BOTH NIGHTS
SHOW PLENTY OF LOW LEVEL MOISTURE BEING IN PLACE UNDER THE SFC RIDGE
TO SUPPORT FOG FORMATION...SO LONG AS THERE IS MINIMAL CLOUD COVER.
WITH UNCERTAINTIES IN CLOUD COVER BOTH NIGHTS...DID NOT MENTION ANY
FOG IN THE FORECAST...BUT THIS IS SOMETHING THAT WILL NEED TO BE
WATCHED CLOSELY.
WHEN IT COMES TO PRECIPITATION...NOW DOWN TO BASICALLY ONE
MODEL...THE GEM...THAT IS STILL BRINGING PRECIP TO THE AREA MID WEEK
IN ASSOCIATION WITH THE DEEP TROUGH NOW OVER THE 4-CORNERS. MODELS
ALL PRETTY SIMILAR WITH TAKING THIS UPPER LOW FROM NEW MEXICO TODAY
OVER TO THE LAKE ERIE REGION BY WEDNESDAY. THIS WILL BE QUITE THE
IMPRESSIVE SYSTEM...WITH H5 HEIGHT FALLS ON THE ORDER OF 200M AND A
WELL DEFINED H7 LOW. HEAVY SNOW SWATH STILL LOOKS LIKE A GOOD BET
FROM THE NE TX PANHANDLE UP INTO THE CHICAGO METRO AREA AND MID
MICHIGAN. FOR THE MPX AREA...WE WILL BE BATTLING RATHER STRONG DRY
AIR ADVECTION AND SUBSIDENCE ON THE NORTH SIDE OF THE SYSTEM. ONLY
REAL HOPE FOR PRECIP IN THE MPX AREA LOOKS TO COME TUESDAY NIGHT
INTO WEDNESDAY AS SFC LOW IS TRACKING FROM SRN IL TOWARD NRN OH. THE
QUESTION HERE IS HOW FAR NW DOES EXPANSIVE WRAP-AROUND PRECIP SHIELD
MAKE IT. AT THIS POINT...ONLY THE WRN OUTLIER GEM IS SHOWING PRECIP
ACROSS THE MPX CWA...WITH EVEN THE 24.03 SREF TRENDING SE WITH
PRECIP...KEEPING EVEN ERN AREAS WEST OF THE PRECIP. IF THIS TREND
CONTINUES...FUTURE SHIFTS COULD PROBABLY START PULLING OUT PRECIP
MENTION COMPLETELY. AS FOR WIND AND BLOWING SNOW POTENTIAL MID
WEEK...STILL EXPECT SPEEDS TO PICK UP TUESDAY THROUGH THURSDAY...BUT
WITH THE MAIN SFC LOW GOING AS FAR SOUTH AS IT IS...NOT EXPECTING
WINDS STRONG ENOUGH TO LEAD TO SIGNIFICANT ISSUES. LIKE TO SEE GUST
POTENTIAL OVER 30 MPH TO START SEEING SIGNIFICANT BLOWING SNOW
ISSUES...AND FORECAST SOUNDINGS FROM THE GFS KEEP EVERYTHING IN THE
20S.
FINALLY...WITH TEMPERATURES...NOT EXPECTING MUCH VARIATION OVER THE
NEXT WEEK AS 925-850 TEMPS LOOK TO STAY MORE OR LESS UNCHANGED. THIS
MEANS WE SHOULD CONTINUE TO SEE LOWER ALBEDO AREAS ACROSS CENTRAL
AND EAST CENTRAL MN INTO WRN WI WITH HIGHS MAINLY IN THE 30S...WHILE
HIGHER ALBEDO AREAS FROM WEST CENTRAL INTO SOUTH CENTRAL MN SEE HIGH
MAINLY SEE IN THE 20S. FOR LOWS...FOR THE NEXT COUPLE OF NIGHTS WITH
THE COL IN THE PRESSURE FIELD REMAINING OVERHEAD...THIS WILL LEAD TO
THE POTENTIAL FOR LOWS AROUND ZERO WHERE EVER A FEW HOURS OF
CLEARING CAN BE SEEN. OTHERWISE...LOWS WILL REMAIN ON THE MILD END
UNDER THE INFLUENCE OF CLOUDS...REMAINING UP IN THE TEENS AND 20S.
&&
.AVIATION.../06Z TAF ISSUANCE/
A BATCH OF VFR CIGS REMAINS ALONG AND EAST OF A LINE FROM RZN...TO
FCM...TO LVN AT TAF ISSUANCE TIME. LEVELS HAVE BEEN RUNNING BETWEEN 031
TO 040 IN THOSE AREAS. THE CLEARING LINE HAS SLOWED ITS
PROGRESSION EAST...SO EXPECTING THESE CIGS TO HANG IN FOR THE
OVERNIGHT. FURTHER WEST...FREEZING FOG IS BECOMING WIDESPREAD AND
LOCALLY DENSE WITH AXN EXPECTED TO REMAIN LIFR THROUGH MUCH OF THE
OVERNIGHT. A DETERIORATING VSBY TREND IS FORECAST AT STC AND RWF
DURING THE NEXT SEVERAL HOURS. HIGH CLOUDS OVER THE DAKOTAS WILL
SPREAD EAST EARLY SUNDAY MORNING WHICH COULD HELP IMPROVE
CONDITIONS A BIT NEAR SUNRISE. VFR CONDITIONS THEN RETURN BY
SUNDAY AFTERNOON.
KMSP...VFR CIGS OVERHEAD AT TAF ISSUANCE TIME...BUT CIGS HAVE BEEN
HOVERING NEAR THE VFR/MVFR CRITERIA THRESHOLD DURING THE LAST
SEVERAL HOURS. SHOULD SEE SOME DECREASE IN CLOUD COVER BY 09Z.
THEREAFTER...COULD SEE REDUCTIONS IN VSBY AND A REDEVELOPMENT OF
MVFR CIGS WITH THE LIGHT FOG/MIST. VFR CONDITIONS EXPECTED LATE
SUNDAY MORNING THROUGH THE EVENING WITH LIGHT WINDS.
/OUTLOOK FOR KMSP/
MON...MVFR WITH -SN POSSIBLE. WINDS ENE AT 5KTS.
TUE...MVFR WITH IFR AND -SN POSSIBLE WINDS N AT 10G15KTS.
WED...MVFR WITH -SN POSSIBLE. WINDS NNE AT 10KTS.
&&
.MPX WATCHES/WARNINGS/ADVISORIES...
MN...FREEZING FOG ADVISORY UNTIL 9 AM CST THIS MORNING FOR BLUE EARTH-
BROWN-CARVER-CHIPPEWA-DOUGLAS-FARIBAULT-FREEBORN-KANDIYOHI-
LE SUEUR-MARTIN-MCLEOD-MEEKER-NICOLLET-POPE-RENVILLE-RICE-
SCOTT-SIBLEY-STEARNS-STEELE-STEVENS-SWIFT-TODD-WASECA-
WATONWAN-WRIGHT.
WI...NONE.
&&
$$
MPG/BORGHOFF
AREA FORECAST DISCUSSION
NWS HASTINGS NE
813 PM CST MON FEB 25 2013
.UPDATE...
ISSUED AT 812 PM CST MON FEB 25 2013
SNOW BANDS HAVE SET UP SEVERAL COUNTIES SOUTH OF OUR FORECAST AREA
AND BASED ON RECENT MODELS AND MODEL TRENDS IT SEEMS UNLIKELY THAT
WE WILL SEE ANY ACCUMULATING SNOW IN OUR CWA TONIGHT.
THEREFORE...HAVE COMPLETELY REMOVED THE POPS FOR TONIGHT THAT WERE
PREVIOUSLY LOCATED ACROSS OUR SOUTHEASTERN ZONES.
INCREASING LOW CLOUDS AND FOG LATE TONIGHT CONTINUES TO BE A
POSSIBILITY.
&&
.SHORT TERM...(THIS EVENING THROUGH TUESDAY)
ISSUED AT 346 PM CST MON FEB 25 2013
TONIGHT THROUGH TUESDAY. FOCUS IS ON WHETHER PORTIONS
OF OUR SOUTHERN/EASTERN ZONES WILL SEE ANY LIGHT SNOWFALL TONIGHT
AND TUESDAY. WATER VAPOR IMAGERY PLACED AN UPPER LOW PRESSURE SYSTEM IN
NORTH TX...AND THE FAR NORTH END OF THE DEFORMATION PCPN EXTENDED
INTO NC KS. UPSTREAM...ANOTHER TROUGH HAS MOVED INLAND TO THE
NORTHERN ROCKIES FM THE PACIFIC NORTHWEST.
THROUGH TONIGHT...THE SOUTHERN PLAINS UPPER LOW PRESSURE SYSTEM WILL
LIFT NORTHEAST ACROSS ARKANSAS WITH OUR SOUTHEAST ZONES REMAINING ON
THE NORTHWEST EDGE OF THE DEFORMATION/WRAPAROUND PCPN AND WILL CARRY
SOME LOW POPS INTO THE NIGHT. LOW CLOUDS LOOK TO SETTLE BACK ACROSS
OUR REGION AND SOME QUESTION REMAINS ON FOG POTENTIAL WITH SREF
PROBS INDICATING 20 TO 70PCNT CHCS OF VSBYS BELOW ONE MILE...AND
HRRR SUGGESTS MUCH OF OUR CWA...ALL BUT THE SOUTHEAST...WILL SEE LOW
VSBYS. HAVE WENT AHEAD AND INCLUDED FOG IN THE FORECAST FOR
TONIGHT...MAINLY AFTER MIDNIGHT ALTHOUGH WE COULD SEE DEVELOPMENT
SHORTLY AFTER DARK AND WILL NEED TO MONITOR TIMING/VSBY TRENDS.
ON TUESDAY...WE COULD SEE SOME LINGERING LIGHT SNOW IN OUR
EAST/SOUTHEAST ZONES AS SOUTHERN PLAINS SYSTEM LIFTS OUT...THEN LIFT
INCREASES AGAIN AS AFOREMENTIONED UPSTREAM PACIFIC NW SYSTEM REACHES
THE CENTRAL PLAINS STATES. CONFIDENCE IS NOT HIGH ON HOW MUCH SNOW
WILL BE AROUND DURING THE DAY...WITH MAIN FOCUS IN OUR EASTERN
ZONES...AND HAVE KEPT POPS RELATIVELY LOW. CHCS LOOK SLIGHTLY
BETTER HEADING INTO TUESDAY NIGHT AS THE SYSTEM TRANSLATES
EASTWARD...WITH LIFT INCREASING IN DIVERGENCE ALOFT IN LFQ OF
SOUTHERN PLAINS JET AND DYNAMICS ASSOCIATED WITH WAVE ITSELF.
REGARDING TEMPS...LOWS TONIGHT WILL BE DEPENDENT ON CLOUD COVER AND
COULD SEE A DECENT DROP OFF IN OUR FAR WESTERN ZONES WHERE SKIES
HAVE CLEARED. ON TUESDAY...NOT LOOKING FOR MUCH CHANGE IN AIRMASS
AND HAVE AIMED HIGHS SIMILAR TO TODAYS.
.LONG TERM...(TUESDAY EVENING THROUGH THROUGH MONDAY)
ISSUED AT 346 PM CST MON FEB 25 2013
TUESDAY EVENING THROUGH NEXT MONDAY. AS A WHOLE...THIS
6-DAY PERIOD IS LOOKING LARGELY PRECIPITATION-FREE...AND WITH A
FAIRLY DECENT WARMING TREND BACK UP TO NEAR LATE FEB/EARLY MARCH
NORMS. THAT BEING SAID...THE MAIN CONCERN OF THE LONG RANGE WILL
COME RIGHT AWAY TUESDAY NIGHT...WITH SOME MODELS SHOWING SOME DECENT
1-2+ INCH SNOW POTENTIAL MAINLY IN OUR EASTERN AREAS...WHILE OTHERS
ADVERTISE ONLY A LIGHT DUSTING AT BEST.
STARTING WITH TUESDAY EVENING/NIGHT...THE MID/UPPER AIR PATTERN IS
KIND OF INTERESTING...AS THE POWERFUL VORT MAX CHURNING ALONG THE
RED RIVER VALLEY TODAY WILL BE DEPARTING WELL TO OUR EAST THROUGH
THE OHIO VALLEY...WHILE THE NEXT UPSTREAM SHORTWAVE TROUGH THEN
DROPS INTO THE MEAN FLOW IN ITS WAKE...AND SLIDES EASTWARD ACROSS
THE CENTRAL PLAINS IN SOME WAY...SHAPE OR FORM. FOCUSING SOLELY ON
06Z TUESDAY NIGHT...THE LATEST RUNS OF THE ECMWF/NAM/GFS ARE IN
FAIRLY GOOD AGREEMENT WITH A MODEST 500MB CLOSED LOW DEVELOPING OVER
KS...WITH A RESULTANT NORTH-SOUTH BAND OF MID LEVEL FRONTOGENESIS
THEN MIGRATING EAST ALONG ITS NORTHERN PERIPHERY ACROSS THE LOCAL
AREA. THE ULTIMATE...AND STILL UNANSWERED QUESTION...IS JUST HOW
MUCH SNOW MIGHT TRY TO DEVELOP FROM THIS FORCING AS THE MID LEVEL
LOW PASSES. THINKING AT THIS POINT THAT THE 2-3+ INCHES OF SNOW
ADVERTISED BY THE 12Z GFS ACROSS MUCH OF OUR EASTERN CWA IS
DOWNRIGHT OVERDONE...WHILE OTHER MODELS SUCH AS THE 12Z ECMWF HARDLY
BRING A DUSTING INTO MAINLY THE SOUTHEAST QUADRANT OF THE CWA.
TURNING TO HIGHER-RES MODELS...THE 12Z 4KM WRF-NMM REFLECTIVITY PROG
CLEARLY SHOWS A SOMEWHAT ORGANIZED BAND OF SNOW DEVELOPING MAINLY
WITHIN THE EASTERN 2/3 OF THE CWA AND GRADUALLY SLIDING
SOUTH-SOUTHEAST AS THE NIGHT WEARS ON. TAKING A REASONABLE MIDDLE
GROUND OF THE ABOVE SOLUTIONS...HAVE INCREASED POPS A BIT INTO THE
30-50 PERCENT RANGE ACROSS THE EASTERN HALF OF THE CWA...AND
EXTENDED SLIGHT POPS A BIT FARTHER WEST THAN PREVIOUS FORECAST...BUT
STILL NOT QUITE READY TO GO LIKELY POPS YET ANYWHERE. FOR TUESDAY
EVENING/NIGHT SNOWFALL AMOUNTS...AGAIN PLAYED A MIDDLE GROUND
RANGING FROM A FEW TENTHS OF AN INCH WEST OF HWY 281...AROUND
ONE-HALF INCH ALONG HIGHWAY 281...AND ALMOST AN INCH IN OUR FAR EAST
ESPECIALLY THE FILLMORE/THAYER COUNTY AREA. BOTTOM LINE IS...THIS
DOES NOT LOOK A BIG ENOUGH DEAL TO ADVERTISE IN THE HAZARDOUS
WEATHER OUTLOOK...BUT JUST KNOW THAT A BRIEF PERIOD OF STEADY SNOW
IS POSSIBLE AT SOME POINT TUESDAY NIGHT. GIVEN THE INHERENT
UNCERTAINTY IN EXACTLY WHERE SNOW SETS UP...OPTED TO KEEP THE
POPS/WX GRIDS AS SIMPLE AS POSSIBLE IN ONE 12-HOUR BLOCK...REALIZING
THAT FUTURE SHIFTS CAN ADD SOME MORE DETAILS. TURNING TO OTHER
ELEMENTS FOR TUESDAY NIGHT...ANTICIPATE THE COMBINATION OF FAIRLY
WIDESPREAD CLOUD COVER AND GRADUALLY INCREASING NORTHWEST BREEZES OF
10-15 MPH TO HELP HOLD TEMPS UP A BIT...AND THUS NUDGED UP 2-3
DEGREES FROM PREVIOUS IN MOST AREAS...AND KEEPING MOST NO LOWER THAN
MID 20S.
WEDNESDAY DAYTIME/WEDNESDAY NIGHT...NORTHERLY FLOW DOMINATES THE MID
LEVELS...AS THE AFOREMENTIONED SHORTWAVE FROM TUESDAY NIGHT GRADUALLY
DEPARTS EASTWARD...AND A RIDGE STARTS TO TAKE SHAPE OVER THE PACIFIC
COAST REGION. CONFIDENCE IS NOT OVERLY HIGH ON SKY COVER
WEDNESDAY...BUT HAVE KEPT IT PARTLY-MOSTLY CLOUDY ALL AREAS. ALTHOUGH
HAVE LEFT OUT ANY PRECIP-MENTION FOR NOW...LATER SHIFTS WILL NEED TO
MAKE SURE THAT A TOKEN FLURRY MENTION ISN/T JUSTIFIED. THE MAIN
STORY WEDNESDAY WILL BE A FAIRLY BREEZY/MARGINALLY WINDY DAY...AS
DECENT MIXING AND AN ENHANCED PRESSURE GRADIENT BETWEEN THE
DEPARTING SURFACE LOW AND A BUILDING CENTRAL ROCKIES HIGH SHOULD
PROMOTE SUSTAINED NORTHWEST WINDS 15-25 MPH WITH SOME GUSTS UP TO
AROUND 35 MPH. HOWEVER...SUSTAINED SPEEDS SHOULD BE AT LEAST 5 MPH
SHORT OF LOW-END WIND ADVISORY CRITERIA. DESPITE PLENTY OF
CLOUDS...OPTED TO BUMP UP HIGHS A FEW DEGREES GIVEN GOOD MIXING AND
RECENT TREND OF FORECAST VALUES BEING TOO COOL...NOW AIMING FOR
UPPER 30S MOST ALL AREAS. ALSO NUDGED UP WED NIGHT LOWS A BIT WITH
BREEZES AROUND 10 MPH AND POSSIBLE LINGERING LOW CLOUDS...WITH MOST
AREAS HOLDING UP LOWER 20S.
THURSDAY/THURSDAY NIGHT...THE WESTERN CONUS MID/UPPER RIDGE
CONTINUES TO EXPAND AND BUILD EASTWARD A BIT...WHILE A
MOISTURE-STARVED AND FAIRLY WEAK SHORTWAVE TROUGH SLIDES OVER THE
LOCAL AREA IN NORTHWEST FLOW. AGAIN...SUPPOSE A FEW FLURRIES ARE NOT
OUT OF THE QUESTION BUT THERE/S STILL PLENTY OF TIME TO INSERT THESE
IF NEEDED. LOOKS LIKE ANOTHER DAY OF STEADY NORTH-NORTHWEST
BREEZES...BUT NOT QUITE AS STRONG AS WEDNESDAY WITH SUSTAINED SPEEDS
GENERALLY 15-20 MPH AT MOST. AGAIN NUDGED UP HIGHS A FEW DEGREES
MOST AREAS...RESULTING IN MID OR UPPER 30S.
FRIDAY/FRIDAY NIGHT...THE EASTERN EDGE OF THE NOW RATHER EXPANSIVE
WESTERN CONUS MID/UPPER RIDGE WILL START BUILDING EASTWARD OVER THE
PLAINS...ALTHOUGH COULD STILL SEE A FAIR AMOUNT OF MID LEVEL CLOUD
COVER ASSOCIATED WITH A FAIRLY STOUT 100+KT NORTH-SOUTH UPPER JET
AXIS TRANSLATING ACROSS THE REGION. FOR HIGH TEMPS...YET AGAIN MADE
A SLIGHT UPWARD NUDGE...RANGING FROM LOW 30S EAST TO MID-UPPER 30S
FAR WEST.
SATURDAY/SATURDAY NIGHT...STEADY MID LEVEL HEIGHT RISES CONTINUE AS
THE AFOREMENTIONED EXPANSIVE RIDGE FINALLY BECOMES MORE OF A DOMINANT
INFLUENCE OVER THE CENTRAL PLAINS. ALTHOUGH MODELS DIFFER ON THE
MAGNITUDE OF LOW LEVEL WARM AIR ADVECTION...THE PREFERRED ECWMF
SHOWS A FAVORABLE DOWNSLOPING WEST-NORTHWEST COMPONENT...WHICH
DESPITE LINGERING SNOW COVER WOULD RESULT IN A NICE BOOST...AND
AGAIN NUDGED UP HIGHS SLIGHTLY RANGING FROM UPPER 30S EAST TO
LOW-MID 40S WEST.
SUNDAY/SUNDAY NIGHT...THE MID LEVEL RIDGE AXIS SLIDES OVERHEAD AND
STARTS TO DAMPEN A BIT IN RESPONSE TO THE NEXT SHORTWAVE TROUGH OF
INTEREST SLIDING INTO THE PACIFIC NORTHWEST/NORTHERN ROCKIES. IF
OVERALL TRENDS HOLD IN THE UPPER AIR AND SURFACE PATTERN...OUR FORECAST
HIGHS MAINLY IN THE MID 40S MAY NOT BE WARM ENOUGH...AS 12Z MEX
GUIDANCE EVEN PUSHES SOME SPOTS OVER 50...BUT WILL PLAY THE GRADUAL
RAMP-UP GAME FOR NOW. CERTAINLY BY THIS POINT MOST LINGERING SNOW
COVER SHOULD BITE THE DUST.
MONDAY...THE INITIALIZED ALLBLEND GUIDANCE TRIED INSERTING POPS
ACROSS PARTS OF THE CWA...BUT THIS SEEMED TO BE LARGELY BASED OFF
THE 00Z ECMWF RUN...AND GIVEN THAT THE NEW 12Z RUN KEEPS THE MAIN
SIGNAL FOR MEASURABLE PRECIP WELL NORTH/WEST OF THE CWA THROUGH THE
DAY...HAVE OPTED TO KEEP IT DRY FOR NOW WITH POTENTIALLY SOME PRECIP
CHANCES ENTERING THE PICTURE JUST BEYOND THE OFFICIAL FORECAST
PERIOD INTO MONDAY NIGHT/TUESDAY. AS IS OFTEN THE CASE 7 DAYS
OUT...CONFIDENCE IN HIGH TEMPS ISN/T OVERLY HIGH...BUT WILL RUN WITH
A RANGE FROM LOW 40S NORTHEAST TO UPPER 40S SOUTHWEST FOR NOW.
&&
.AVIATION...KGRI 00Z TAF. LOW CLOUDS AND POSSIBLE FOG WILL BE THE
BIG CONCERNS THAT MAY COME INTO PLAY DURING THE EARLY MORNING
HOURS. CONTINUED SNOW MELT WITH LIGHT WINDS MAY BE ENOUGH TO
PRODUCE FOG...BUT THE HIGH CLOUDS MAY LIMIT THE RADIATIONAL
COOLING. THE HRRR MODEL AND THE SREF BOTH SHOW FOG POTENTIAL AND
DECIDED TO INCLUDE SOME LOWER VISIBILITIES IN THE TAF DURING THE
MOST LIKELY TIME FOR FOG DURING THE HOURS RIGHT AROUND DAWN. FOG
AND LOW STRATUS GO NEARLY HAND IN HAND AND THEREFORE HAVE ALSO
INCLUDED SOME LOWER CEILINGS FOR THE EARLY MORNING HOURS.
&&
.GID WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
KS...NONE.
&&
$$
UPDATE...WESELY
SHORT TERM...FAY
LONG TERM...PFANNKUCH
AVIATION...27
AREA FORECAST DISCUSSION
NWS HASTINGS NE
559 PM CST MON FEB 25 2013
.SHORT TERM...(THIS EVENING THROUGH TUESDAY)
ISSUED AT 346 PM CST MON FEB 25 2013
TONIGHT THROUGH TUESDAY. FOCUS IS ON WHETHER PORTIONS
OF OUR SOUTHERN/EASTERN ZONES WILL SEE ANY LIGHT SNOWFALL TONIGHT
AND TUESDAY. WATER VAPOR IMAGERY PLACED AN UPPER LOW PRESSURE SYSTEM IN
NORTH TX...AND THE FAR NORTH END OF THE DEFORMATION PCPN EXTENDED
INTO NC KS. UPSTREAM...ANOTHER TROUGH HAS MOVED INLAND TO THE
NORTHERN ROCKIES FM THE PACIFIC NORTHWEST.
THROUGH TONIGHT...THE SOUTHERN PLAINS UPPER LOW PRESSURE SYSTEM WILL
LIFT NORTHEAST ACROSS ARKANSAS WITH OUR SOUTHEAST ZONES REMAINING ON
THE NORTHWEST EDGE OF THE DEFORMATION/WRAPAROUND PCPN AND WILL CARRY
SOME LOW POPS INTO THE NIGHT. LOW CLOUDS LOOK TO SETTLE BACK ACROSS
OUR REGION AND SOME QUESTION REMAINS ON FOG POTENTIAL WITH SREF
PROBS INDICATING 20 TO 70PCNT CHCS OF VSBYS BELOW ONE MILE...AND
HRRR SUGGESTS MUCH OF OUR CWA...ALL BUT THE SOUTHEAST...WILL SEE LOW
VSBYS. HAVE WENT AHEAD AND INCLUDED FOG IN THE FORECAST FOR
TONIGHT...MAINLY AFTER MIDNIGHT ALTHOUGH WE COULD SEE DEVELOPMENT
SHORTLY AFTER DARK AND WILL NEED TO MONITOR TIMING/VSBY TRENDS.
ON TUESDAY...WE COULD SEE SOME LINGERING LIGHT SNOW IN OUR
EAST/SOUTHEAST ZONES AS SOUTHERN PLAINS SYSTEM LIFTS OUT...THEN LIFT
INCREASES AGAIN AS AFOREMENTIONED UPSTREAM PACIFIC NW SYSTEM REACHES
THE CENTRAL PLAINS STATES. CONFIDENCE IS NOT HIGH ON HOW MUCH SNOW
WILL BE AROUND DURING THE DAY...WITH MAIN FOCUS IN OUR EASTERN
ZONES...AND HAVE KEPT POPS RELATIVELY LOW. CHCS LOOK SLIGHTLY
BETTER HEADING INTO TUESDAY NIGHT AS THE SYSTEM TRANSLATES
EASTWARD...WITH LIFT INCREASING IN DIVERGENCE ALOFT IN LFQ OF
SOUTHERN PLAINS JET AND DYNAMICS ASSOCIATED WITH WAVE ITSELF.
REGARDING TEMPS...LOWS TONIGHT WILL BE DEPENDENT ON CLOUD COVER AND
COULD SEE A DECENT DROP OFF IN OUR FAR WESTERN ZONES WHERE SKIES
HAVE CLEARED. ON TUESDAY...NOT LOOKING FOR MUCH CHANGE IN AIRMASS
AND HAVE AIMED HIGHS SIMILAR TO TODAYS.
.LONG TERM...(TUESDAY EVENING THROUGH THROUGH MONDAY)
ISSUED AT 346 PM CST MON FEB 25 2013
TUESDAY EVENING THROUGH NEXT MONDAY. AS A WHOLE...THIS
6-DAY PERIOD IS LOOKING LARGELY PRECIPITATION-FREE...AND WITH A
FAIRLY DECENT WARMING TREND BACK UP TO NEAR LATE FEB/EARLY MARCH
NORMS. THAT BEING SAID...THE MAIN CONCERN OF THE LONG RANGE WILL
COME RIGHT AWAY TUESDAY NIGHT...WITH SOME MODELS SHOWING SOME DECENT
1-2+ INCH SNOW POTENTIAL MAINLY IN OUR EASTERN AREAS...WHILE OTHERS
ADVERTISE ONLY A LIGHT DUSTING AT BEST.
STARTING WITH TUESDAY EVENING/NIGHT...THE MID/UPPER AIR PATTERN IS
KIND OF INTERESTING...AS THE POWERFUL VORT MAX CHURNING ALONG THE
RED RIVER VALLEY TODAY WILL BE DEPARTING WELL TO OUR EAST THROUGH
THE OHIO VALLEY...WHILE THE NEXT UPSTREAM SHORTWAVE TROUGH THEN
DROPS INTO THE MEAN FLOW IN ITS WAKE...AND SLIDES EASTWARD ACROSS
THE CENTRAL PLAINS IN SOME WAY...SHAPE OR FORM. FOCUSING SOLELY ON
06Z TUESDAY NIGHT...THE LATEST RUNS OF THE ECMWF/NAM/GFS ARE IN
FAIRLY GOOD AGREEMENT WITH A MODEST 500MB CLOSED LOW DEVELOPING OVER
KS...WITH A RESULTANT NORTH-SOUTH BAND OF MID LEVEL FRONTOGENESIS
THEN MIGRATING EAST ALONG ITS NORTHERN PERIPHERY ACROSS THE LOCAL
AREA. THE ULTIMATE...AND STILL UNANSWERED QUESTION...IS JUST HOW
MUCH SNOW MIGHT TRY TO DEVELOP FROM THIS FORCING AS THE MID LEVEL
LOW PASSES. THINKING AT THIS POINT THAT THE 2-3+ INCHES OF SNOW
ADVERTISED BY THE 12Z GFS ACROSS MUCH OF OUR EASTERN CWA IS
DOWNRIGHT OVERDONE...WHILE OTHER MODELS SUCH AS THE 12Z ECMWF HARDLY
BRING A DUSTING INTO MAINLY THE SOUTHEAST QUADRANT OF THE CWA.
TURNING TO HIGHER-RES MODELS...THE 12Z 4KM WRF-NMM REFLECTIVITY PROG
CLEARLY SHOWS A SOMEWHAT ORGANIZED BAND OF SNOW DEVELOPING MAINLY
WITHIN THE EASTERN 2/3 OF THE CWA AND GRADUALLY SLIDING
SOUTH-SOUTHEAST AS THE NIGHT WEARS ON. TAKING A REASONABLE MIDDLE
GROUND OF THE ABOVE SOLUTIONS...HAVE INCREASED POPS A BIT INTO THE
30-50 PERCENT RANGE ACROSS THE EASTERN HALF OF THE CWA...AND
EXTENDED SLIGHT POPS A BIT FARTHER WEST THAN PREVIOUS FORECAST...BUT
STILL NOT QUITE READY TO GO LIKELY POPS YET ANYWHERE. FOR TUESDAY
EVENING/NIGHT SNOWFALL AMOUNTS...AGAIN PLAYED A MIDDLE GROUND
RANGING FROM A FEW TENTHS OF AN INCH WEST OF HWY 281...AROUND
ONE-HALF INCH ALONG HIGHWAY 281...AND ALMOST AN INCH IN OUR FAR EAST
ESPECIALLY THE FILLMORE/THAYER COUNTY AREA. BOTTOM LINE IS...THIS
DOES NOT LOOK A BIG ENOUGH DEAL TO ADVERTISE IN THE HAZARDOUS
WEATHER OUTLOOK...BUT JUST KNOW THAT A BRIEF PERIOD OF STEADY SNOW
IS POSSIBLE AT SOME POINT TUESDAY NIGHT. GIVEN THE INHERENT
UNCERTAINTY IN EXACTLY WHERE SNOW SETS UP...OPTED TO KEEP THE
POPS/WX GRIDS AS SIMPLE AS POSSIBLE IN ONE 12-HOUR BLOCK...REALIZING
THAT FUTURE SHIFTS CAN ADD SOME MORE DETAILS. TURNING TO OTHER
ELEMENTS FOR TUESDAY NIGHT...ANTICIPATE THE COMBINATION OF FAIRLY
WIDESPREAD CLOUD COVER AND GRADUALLY INCREASING NORTHWEST BREEZES OF
10-15 MPH TO HELP HOLD TEMPS UP A BIT...AND THUS NUDGED UP 2-3
DEGREES FROM PREVIOUS IN MOST AREAS...AND KEEPING MOST NO LOWER THAN
MID 20S.
WEDNESDAY DAYTIME/WEDNESDAY NIGHT...NORTHERLY FLOW DOMINATES THE MID
LEVELS...AS THE AFOREMENTIONED SHORTWAVE FROM TUESDAY NIGHT GRADUALLY
DEPARTS EASTWARD...AND A RIDGE STARTS TO TAKE SHAPE OVER THE PACIFIC
COAST REGION. CONFIDENCE IS NOT OVERLY HIGH ON SKY COVER
WEDNESDAY...BUT HAVE KEPT IT PARTLY-MOSTLY CLOUDY ALL AREAS. ALTHOUGH
HAVE LEFT OUT ANY PRECIP-MENTION FOR NOW...LATER SHIFTS WILL NEED TO
MAKE SURE THAT A TOKEN FLURRY MENTION ISN/T JUSTIFIED. THE MAIN
STORY WEDNESDAY WILL BE A FAIRLY BREEZY/MARGINALLY WINDY DAY...AS
DECENT MIXING AND AN ENHANCED PRESSURE GRADIENT BETWEEN THE
DEPARTING SURFACE LOW AND A BUILDING CENTRAL ROCKIES HIGH SHOULD
PROMOTE SUSTAINED NORTHWEST WINDS 15-25 MPH WITH SOME GUSTS UP TO
AROUND 35 MPH. HOWEVER...SUSTAINED SPEEDS SHOULD BE AT LEAST 5 MPH
SHORT OF LOW-END WIND ADVISORY CRITERIA. DESPITE PLENTY OF
CLOUDS...OPTED TO BUMP UP HIGHS A FEW DEGREES GIVEN GOOD MIXING AND
RECENT TREND OF FORECASTED VALUES BEING TOO COOL...NOW AIMING FOR
UPPER 30S MOST ALL AREAS. ALSO NUDGED UP WED NIGHT LOWS A BIT WITH
BREEZES AROUND 10 MPH AND POSSIBLE LINGERING LOW CLOUDS...WITH MOST
AREAS HOLDING UP LOWER 20S.
THURSDAY/THURSDAY NIGHT...THE WESTERN CONUS MID/UPPER RIDGE
CONTINUES TO EXPAND AND BUILD EASTWARD A BIT...WHILE A
MOISTURE-STARVED AND FAIRLY WEAK SHORTWAVE TROUGH SLIDES OVER THE
LOCAL AREA IN NORTHWEST FLOW. AGAIN...SUPPOSE A FEW FLURRIES ARE NOT
OUT OF THE QUESTION BUT THERE/S STILL PLENTY OF TIME TO INSERT THESE
IF NEEDED. LOOKS LIKE ANOTHER DAY OF STEADY NORTH-NORTHWEST
BREEZES...BUT NOT QUITE AS STRONG AS WEDNESDAY WITH SUSTAINED SPEEDS
GENERALLY 15-20 MPH AT MOST. AGAIN NUDGED UP HIGHS A FEW DEGREES
MOST AREAS...RESULTING IN MID OR UPPER 30S.
FRIDAY/FRIDAY NIGHT...THE EASTERN EDGE OF THE NOW RATHER EXPANSIVE
WESTERN CONUS MID/UPPER RIDGE WILL START BUILDING EASTWARD OVER THE
PLAINS...ALTHOUGH COULD STILL SEE A FAIR AMOUNT OF MID LEVEL CLOUD
COVER ASSOCIATED WITH A FAIRLY STOUT 100+KT NORTH-SOUTH UPPER JET
AXIS TRANSLATING ACROSS THE REGION. FOR HIGH TEMPS...YET AGAIN MADE
A SLIGHT UPWARD NUDGE...RANGING FROM LOW 30S EAST TO MID-UPPER 30S
FAR WEST.
SATURDAY/SATURDAY NIGHT...STEADY MID LEVEL HEIGHT RISES CONTINUE AS
THE AFOREMENTIONED EXPANSIVE RIDGE FINALLY BECOMES MORE OF A DOMINANT
INFLUENCE OVER THE CENTRAL PLAINS. ALTHOUGH MODELS DIFFER ON THE
MAGNITUDE OF LOW LEVEL WARM AIR ADVECTION...THE PREFERRED ECWMF
SHOWS A FAVORABLE DOWNSLOPING WEST-NORTHWEST COMPONENT...WHICH
DESPITE LINGERING SNOW COVER WOULD RESULT IN A NICE BOOST...AND
AGAIN NUDGED UP HIGHS SLIGHTLY RANGING FROM UPPER 30S EAST TO
LOW-MID 40S WEST.
SUNDAY/SUNDAY NIGHT...THE MID LEVEL RIDGE AXIS SLIDES OVERHEAD AND
STARTS TO DAMPEN A BIT IN RESPONSE TO THE NEXT SHORTWAVE TROUGH OF
INTEREST SLIDING INTO THE PACIFIC NORTHWEST/NORTHERN ROCKIES. IF
OVERALL TRENDS HOLD IN THE UPPER AIR AND SURFACE PATTERN...OUR FORECAST
HIGHS MAINLY IN THE MID 40S MAY NOT BE WARM ENOUGH...AS 12Z MEX
GUIDANCE EVEN PUSHES SOME SPOTS OVER 50...BUT WILL PLAY THE GRADUAL
RAMP-UP GAME FOR NOW. CERTAINLY BY THIS POINT MOST LINGERING SNOW
COVER SHOULD BITE THE DUST.
MONDAY...THE INITIALIZED ALLBLEND GUIDANCE TRIED INSERTING POPS
ACROSS PARTS OF THE CWA...BUT THIS SEEMED TO BE LARGELY BASED OFF
THE 00Z ECMWF RUN...AND GIVEN THAT THE NEW 12Z RUN KEEPS THE MAIN
SIGNAL FOR MEASURABLE PRECIP WELL NORTH/WEST OF THE CWA THROUGH THE
DAY...HAVE OPTED TO KEEP IT DRY FOR NOW WITH POTENTIALLY SOME PRECIP
CHANCES ENTERING THE PICTURE JUST BEYOND THE OFFICIAL FORECAST
PERIOD INTO MONDAY NIGHT/TUESDAY. AS IS OFTEN THE CASE 7 DAYS
OUT...CONFIDENCE IN HIGH TEMPS ISN/T OVERLY HIGH...BUT WILL RUN WITH
A RANGE FROM LOW 40S NORTHEAST TO UPPER 40S SOUTHWEST FOR NOW.
&&
.AVIATION...KGRI 00Z TAF. LOW CLOUDS AND POSSIBLE FOG WILL BE THE
BIG CONCERNS THAT MAY COME INTO PLAY DURING THE EARLY MORNING
HOURS. CONTINUED SNOW MELT WITH LIGHT WINDS MAY BE ENOUGH TO
PRODUCE FOG...BUT THE HIGH CLOUDS MAY LIMIT THE RADIATIONAL
COOLING. THE HRRR MODEL AND THE SREF BOTH SHOW FOG POTENTIAL AND
DECIDED TO INCLUDE SOME LOWER VISIBILITIES IN THE TAF DURING THE
MOST LIKELY TIME FOR FOG DURING THE HOURS RIGHT AROUND DAWN. FOG
AND LOW STRATUS GO NEARLY HAND IN HAND AND THEREFORE HAVE ALSO
INCLUDED SOME LOWER CEILINGS FOR THE EARLY MORNING HOURS.
&&
.GID WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
KS...NONE.
&&
$$
SHORT TERM...FAY
LONG TERM...PFANNKUCH
AVIATION...27
AREA FORECAST DISCUSSION
NWS BUFFALO NY
1208 PM EST SUN FEB 24 2013
.SYNOPSIS...
AN UPPER LEVEL LOW WILL BRING OCCASIONAL SNOW SHOWERS THROUGH THE
AFTERNOON WITH ONLY VERY LIGHT ACCUMULATIONS. EXPECT A DRY DAY ON
MONDAY AS HIGH PRESSURE CRESTS INTO THE EASTERN GREAT LAKES REGION.
A LARGE AREA OF LOW PRESSURE WILL APPROACH THE REGION LATE TUESDAY
WITH UNSETTLED WEATHER LASTING FROM TUESDAY NIGHT THROUGH THE END OF
THE WEEK.
&&
.NEAR TERM /THROUGH TONIGHT/...
SURFACE ANALYSIS EARLY THIS AFTERNOON SHOWING A WEAK LOW FADING AWAY
OVER SOUTHERN QUEBEC AS SECONDARY COASTAL CYCLOGENESIS CONTINUES
JUST SOUTHEAST OF CAPE COD. A SHARP MID LEVEL TROUGH EVIDENT IN
WATER VAPOR IMAGERY AND OBJECTIVE RUC ANALYSIS OVER SOUTHERN ONTARIO
AND WESTERN NY AT 17Z WILL SWING EAST ACROSS THE REGION THROUGH MID
AFTERNOON AND CONTINUE TO PROVIDE A PERIOD OF LARGE SCALE ASCENT IN
THE DPVA REGION AHEAD OF THE TROUGH.
RADAR IMAGERY SHOWING RATHER WIDESPREAD LIGHT SNOW SHOWERS ACROSS
WESTERN AND CENTRAL NY AND ALSO THE EASTERN LAKE ONTARIO REGION AS
OF 17Z. THIS WILL CONTINUE INTO THE AFTERNOON...WITH A GENERAL TREND
TOWARDS TAPERING OFF FROM WEST TO EAST AS THE MID LEVEL TROUGH
CONTINUES EAST AND LARGE SCALE ASCENT ENDS.
WITH THE COLD CORE ALOFT CROSSING THE REGION THIS AFTERNOON...850MB
TEMPS DROP TO AROUND -11C. THIS MAY BE JUST COLD ENOUGH TO SUPPORT
SOME VERY LIMITED LAKE ENHANCEMENT. THIS COMBINED WITH UPSLOPE FLOW
MAY PRODUCE UP TO AN INCH OF ACCUMULATION ON THE HILLS OF THE
SOUTHERN TIER AND ALSO ACROSS THE TUG HILL REGION. ELSEWHERE ONLY A
LIGHT COATING OF ACCUMULATION IS EXPECTED...AND WITH THE NOW
STRONGER LATE FEBRUARY SUN ANGLE EXPECT MOST ROADS TO JUST REMAIN
WET.
HIGHS TODAY WILL BE IN THE UPPER 20S ACROSS THE HIGHER TERRAIN OF
THE FORECAST AREA IN THE SOUTHERN TIER AND TUG HILL...WITH LOWER 30S
ACROSS THE LOWER ELEVATIONS OF THE LAKE PLAINS AND CLOSE TO THE LAKE
ERIE SHORE. LOWS TONIGHT WILL BE IN THE LOWER 20S AWAY FROM THE
LAKES...AND IN THE MID TO UPPER 20S ALONG AND DOWNWIND OF THE LAKES
WHERE CLOUDS WILL ALSO LINGER.
&&
.SHORT TERM /MONDAY THROUGH TUESDAY NIGHT/...
AT THE START OF THE PERIOD WE WILL SEE THE UPPER TROUGH SHIFTING
OFF TO OUR EAST AS THE AREA COMES UNDER THE INCREASING INFLUENCE
OF UPPER RIDGING AND HIGH PRESSURE...PUSHING EAST FROM THE GREAT
LAKES AND OHIO VALLEY. THIS WILL SUPPORT A WEAKENING TO THE
NORTHWESTERLY FLOW AND A LOWERING OF OVER-LAKE INVERSION HEIGHTS.
THIS WILL ACT TO SUPPRESS ANY LINGERING LAKE SNOW SHOWERS
SOUTHEAST OF LAKE ONTARIO. BUFR SOUNDINGS SHOWING CONSIDERABLE LOW
LEVEL MOISTURE UNDERNEATH SUBSIDENCE INVERSION AND CONSIDERING
LIGHT NORTHERLY FLOW DEVELOPING...IT MAY BE TAKE AWHILE BEFORE
CLOUDS CAN SCATTER OUT. TEMPERATURES WILL RUN NEAR NORMAL WITH
HIGHS IN THE LOWER TO MID 30S.
MONDAY NIGHT...THE CENTER OF THE SURFACE HIGH WILL MOVE OVERHEAD
THEN SHIFT EAST TO NEW ENGLAND WITH A BETTER CHANCE TO SEE
CLEARING SKIES...ALTHOUGH HIGH CLOUDS MAY BEGIN TO SLIDE OVERHEAD
ACROSS THE WEST AHEAD OF THE NEXT STORM SYSTEM.
THE TUESDAY AND TUESDAY NIGHT TIME FRAME CONTINUES TO BE THE MAIN
FORECAST CHALLENGE...AS THE COMPACT UPPER LEVEL SYSTEM EJECTS INTO
THE OHIO VALLEY. FOR THIS PACKAGE...WE WILL LEAN TOWARD TO THE
OPERATIONAL ECMWF RUN WITH INCREASING SUPPORT FROM THE GFS. THE
SYSTEM WILL BE UNDERGOING AN OCCLUSION PROCESS DURING THIS TIME
FRAME. THIS WEAKENING PROCESS WOULD OFTEN SIGNAL THAT THE
PRECIPITATION SHIELD ON THE NORTHERN SIDE OF THE UPPER LOW WILL
BE WANING...HOWEVER A WELL DEFINED CONVEYOR OF MOISTURE FROM THE
ATLANTIC WILL BE WORKING INTO THE NORTHERN OR COLD SIDE OF THE
SYSTEM. MID TROPOSPHERIC DEFORMATION ALONG THE NORTHERN FLANK OF
THE UPPER LOW IS FORECAST TO BE EXCELLENT WITHIN A HIGHLY
DIFFLUENT UPPER FLOW. THE STRONG DYNAMIC SUPPORT IS EXPECTED TO
LIFT ACROSS WESTERN AND CENTRAL NEW YORK LATE TUESDAY AND TUESDAY
NIGHT DEVELOPING WIDESPREAD PRECIPITATION. THERMAL PROFILES
SUGGESTING PRECIPITATION WILL LIKELY START AS A RAIN DUE TO THE
LATE DAYTIME ARRIVAL...ALTHOUGH A WINTRY MIX COULD BECOME
PROBLEMATIC ALONG THE SOUTHERN TIER. CONCERNS ARISE TUESDAY NIGHT
AS PRECIPITATION MAY FALL AT SUFFICIENT RATES TO CAUSE SIGNIFICANT
DIABATIC COOLING OF LOWER LAYERS ALLOWING FOR A GREATER RISK FOR
SNOW. HEAVY SNOW NOT TOTALLY OUT OF THE QUESTION FOR SOME AREAS AS
A WELL DEFINED TROWAL FEATURE EVOLVES. HOWEVER...TOP CIPS ANALOGS
WERE SHOWING GREATEST SUPPORT FOR SNOWFALL AMOUNTS TO REMAIN
BELOW WARNING CRITERIA.
&&
.LONG TERM /WEDNESDAY THROUGH SATURDAY/...
A BUILDING BLOCKING PATTERN CURRENTLY TAKING SHAPE OVER THE NORTH
ATLANTIC CAN BE SEEN WITHIN THE ECMWF 500MB HEMISPHERIC PLOT AND
CURRENT NEGATIVE PHASE OF THE NAO WHICH WILL MAKE FOR A SLOW-TO-MOVE
WEATHER PATTERN AT LEAST FROM MIDWEEK INTO THE WEEKEND. MODEL
ENSEMBLE FORECASTS FOR THE NAO INDEX SHOW THIS COULD PERSIST INTO
EARLY MARCH AS WELL. THE STORM SYSTEM WHICH WILL BE NEAR THE
FORECAST AREA ON WEDNESDAY WILL CONTINUE TO BRING CLOUDS AND
DIURNALLY INFLUENCED PRECIPITATION. AFTER THE INITIAL WARM FRONTAL
FORCED SLUG OF PRECIP PUSHES THROUGH TUESDAY NIGHT WE WILL SEE
MAINLY SCATTERED SHOWER ACTIVITY AS THE SYSTEM OCCLUDES TO OUR WEST
WEDNESDAY AND WEDNESDAY NIGHT WHICH THE 12Z GFS AND ECMWF AGREE
UPON.
MODELS SHOW THE SYSTEM WILL GET NUDGED EASTWARD THROUGH THURSDAY
WHERE A SLUG OF MOISTURE BENEATH THE UPPER LOW WILL LIKELY AGAIN
BRING RAIN AND SNOW ACROSS THE FORECAST AREA. P-TYPE WILL BE
DIURNALLY INFLUENCED AS DAYTIME TEMPS WILL RISE ABOVE FREEZING IN
MANY SPOTS DURING THE DAY WITH RAIN OCCURRING AND OVERNIGHT TEMPS
FALLING BACK TO NEAR OR BELOW FREEZING WHERE SNOW CAN BE EXPECTED.
FRIDAY AND SATURDAY WITH THE LOW NOW EAST OF THE LOWER LAKES SOME
COLDER AIR MOVES IN AND WITH LINGERING TROUGHINESS ALOFT WE KEPT A
CHANCE OF SNOW IN THE FORECAST. BY SATURDAY WE LOOK TO RETURN TO
BELOW NORMAL WHERE HIGHS MAY NOT BREAK ABOVE FREEZING.
&&
.AVIATION /17Z SUNDAY THROUGH THURSDAY/...
AN UPPER LEVEL LOW WILL CROSS THE REGION THIS AFTERNOON WITH
WIDESPREAD MVFR CIGS/VSBY IN LIGHT SNOW SHOWERS AND A FEW POCKETS OF
IFR VSBY IN STEADIER SNOW. THE SNOW SHOWERS ARE EXPECTED TO
GRADUALLY TAPER OFF FROM WEST TO EAST FROM MID AFTERNOON THROUGH
EARLY EVENING AS THE UPPER LEVEL DISTURBANCE EXITS THE REGION TO THE
EAST. THIS WILL LEAVE BEHIND MAINLY MVFR CIGS THROUGH THE FIRST HALF
OF TONIGHT BEFORE SLOWLY SCATTERING OUT LATE TONIGHT AND MONDAY
MORNING WITH A RETURN TO VFR IN MOST LOCATIONS...ALTHOUGH SOME
POCKETS OF MVFR CIGS WILL LIKELY LINGER THROUGH THE FIRST HALF OF
MONDAY.
OUTLOOK...
TUESDAY...MAINLY VFR.
TUESDAY NIGHT AND WEDNESDAY...IFR WITH SNOW...RAIN AND WINTRY MIX.
THURSDAY AND FRIDAY...MVFR/IFR WITH SNOW SHOWERS LIKELY.
&&
.MARINE...
A WEST WIND OVER LAKE ERIE UNDER CYCLONIC FLOW AND COLD AIR
ADVECTION ALOFT WILL STRENGTHEN TOWARDS 15 TO 20 KNOTS. A SMALL
CRAFT ADVISORY FOR LAKE ERIE WILL BE IN EFFECT THROUGH THE EARLY
EVENING. WINDS AND WAVES WILL ALSO CREATE SMALL CRAFT CONDITIONS ON
LAKE ONTARIO FROM SODUS BAY TO MEXICO BAY AND NORTH TO HENDERSON
BAY. THESE CONDITIONS WILL DEVELOP AROUND MID DAY AND PERSIST
THROUGH THE EVENING.
ON MONDAY AN AREA OF HIGH PRESSURE WILL CROSS THE LAKE WITH MINIMAL
WINDS AND WAVES ON THE LAKES.
&&
.BUF WATCHES/WARNINGS/ADVISORIES...
NY...NONE.
MARINE...SMALL CRAFT ADVISORY UNTIL 6 PM EST THIS EVENING FOR LEZ040-
041.
SMALL CRAFT ADVISORY UNTIL MIDNIGHT EST TONIGHT FOR
LOZ044-045.
&&
$$
SYNOPSIS...HITCHCOCK/WCH
NEAR TERM...HITCHCOCK/WCH
SHORT TERM...TMA
LONG TERM...SMITH
AVIATION...HITCHCOCK
MARINE...WCH
AREA FORECAST DISCUSSION
NWS BUFFALO NY
957 AM EST SUN FEB 24 2013
.SYNOPSIS...
AN UPPER LEVEL LOW WILL BRING OCCASIONAL SNOW SHOWERS THROUGH THE
AFTERNOON WITH ONLY VERY LIGHT ACCUMULATIONS. EXPECT A DRY DAY ON
MONDAY AS HIGH PRESSURE CRESTS INTO THE EASTERN GREAT LAKES REGION.
A LARGE AREA OF LOW PRESSURE WILL APPROACH THE REGION LATE TUESDAY
WITH UNSETTLED WEATHER LASTING FROM TUESDAY NIGHT THROUGH THE END OF
THE WEEK.
&&
.NEAR TERM /THROUGH TONIGHT/...
SURFACE ANALYSIS THIS MORNING SHOWING A WEAK LOW OVER SOUTHERN
QUEBEC WITH SECONDARY COASTAL CYCLOGENESIS UNDERWAY JUST SOUTHEAST
OF CAPE COD. A SHARP MID LEVEL TROUGH EVIDENT IN WATER VAPOR IMAGERY
AND OBJECTIVE RUC ANALYSIS OVER SOUTHERN ONTARIO AT 15Z WILL SWING
EAST ACROSS THE REGION FROM LATE MORNING THROUGH MID AFTERNOON AND
CONTINUE TO PROVIDE A PERIOD OF LARGE SCALE ASCENT IN THE DPVA
REGION AHEAD OF THE TROUGH.
RADAR IMAGERY SHOWING RATHER WIDESPREAD LIGHT SNOW SHOWERS ACROSS
WESTERN NY AND ALSO BEGINNING TO ENTER THE EASTERN LAKE ONTARIO
REGION. BY AFTERNOON AS THE COLD CORE ALOFT CROSSES THE REGION...
850MB TEMPS DROP TO AROUND -11C. THIS MAY BE JUST COLD ENOUGH TO
SUPPORT SOME VERY LIMITED LAKE ENHANCEMENT. THIS COMBINED WITH
UPSLOPE FLOW MAY PRODUCE UP TO AN INCH OF ACCUMULATION ON THE HILLS
OF THE SOUTHERN TIER AND ALSO ACROSS THE TUG HILL REGION. ELSEWHERE
ONLY A LIGHT COATING OF ACCUMULATION IS EXPECTED...AND WITH THE NOW
STRONGER LATE FEBRUARY SUN ANGLE EXPECT MOST ROADS TO JUST REMAIN
WET.
HIGHS TODAY WILL BE IN THE UPPER 20S ACROSS THE HIGHER TERRAIN OF
THE FORECAST AREA IN THE SOUTHERN TIER AND TUG HILL...WITH LOWER 30S
ACROSS THE LOWER ELEVATIONS OF THE LAKE PLAINS AND CLOSE TO THE LAKE
ERIE SHORE. LOWS TONIGHT WILL BE IN THE LOWER 20S AWAY FROM THE
LAKES...AND IN THE MID TO UPPER 20S ALONG AND DOWNWIND OF THE LAKES
WHERE CLOUDS WILL ALSO LINGER.
&&
.SHORT TERM /MONDAY THROUGH TUESDAY NIGHT/...
AT THE START OF THE PERIOD WE WILL SEE THE UPPER TROUGH SHIFTING
OFF TO OUR EAST AS THE AREA COMES UNDER THE INCREASING INFLUENCE
OF UPPER RIDGING AND HIGH PRESSURE...PUSHING EAST FROM THE GREAT
LAKES AND OHIO VALLEY. THIS WILL SUPPORT A WEAKENING TO THE
NORTHWESTERLY FLOW AND A LOWERING OF OVER-LAKE INVERSION HEIGHTS.
THIS WILL ACT TO SUPPRESS ANY LINGERING LAKE SNOW SHOWERS
SOUTHEAST OF LAKE ONTARIO. BUFR SOUNDINGS SHOWING CONSIDERABLE LOW
LEVEL MOISTURE UNDERNEATH SUBSIDENCE INVERSION AND CONSIDERING
LIGHT NORTHERLY FLOW DEVELOPING...IT MAY BE TAKE AWHILE BEFORE
CLOUDS CAN SCATTER OUT. TEMPERATURES WILL RUN NEAR NORMAL WITH
HIGHS IN THE LOWER TO MID 30S.
MONDAY NIGHT...THE CENTER OF THE SURFACE HIGH WILL MOVE OVERHEAD
THEN SHIFT EAST TO NEW ENGLAND WITH A BETTER CHANCE TO SEE
CLEARING SKIES...ALTHOUGH HIGH CLOUDS MAY BEGIN TO SLIDE OVERHEAD
ACROSS THE WEST AHEAD OF THE NEXT STORM SYSTEM.
THE TUESDAY AND TUESDAY NIGHT TIME FRAME CONTINUES TO BE THE MAIN
FORECAST CHALLENGE...AS THE COMPACT UPPER LEVEL SYSTEM EJECTS INTO
THE OHIO VALLEY. FOR THIS PACKAGE...WE WILL LEAN TOWARD TO THE
OPERATIONAL ECMWF RUN WITH INCREASING SUPPORT FROM THE GFS. THE
SYSTEM WILL BE UNDERGOING AN OCCLUSION PROCESS DURING THIS TIME
FRAME. THIS WEAKENING PROCESS WOULD OFTEN SIGNAL THAT THE
PRECIPITATION SHIELD ON THE NORTHERN SIDE OF THE UPPER LOW WILL
BE WANING...HOWEVER A WELL DEFINED CONVEYOR OF MOISTURE FROM THE
ATLANTIC WILL BE WORKING INTO THE NORTHERN OR COLD SIDE OF THE
SYSTEM. MID TROPOSPHERIC DEFORMATION ALONG THE NORTHERN FLANK OF
THE UPPER LOW IS FORECAST TO BE EXCELLENT WITHIN A HIGHLY
DIFFLUENT UPPER FLOW. THE STRONG DYNAMIC SUPPORT IS EXPECTED TO
LIFT ACROSS WESTERN AND CENTRAL NEW YORK LATE TUESDAY AND TUESDAY
NIGHT DEVELOPING WIDESPREAD PRECIPITATION. THERMAL PROFILES
SUGGESTING PRECIPITATION WILL LIKELY START AS A RAIN DUE TO THE
LATE DAYTIME ARRIVAL...ALTHOUGH A WINTRY MIX COULD BECOME
PROBLEMATIC ALONG THE SOUTHERN TIER. CONCERNS ARISE TUESDAY NIGHT
AS PRECIPITATION MAY FALL AT SUFFICIENT RATES TO CAUSE SIGNIFICANT
DIABATIC COOLING OF LOWER LAYERS ALLOWING FOR A GREATER RISK FOR
SNOW. HEAVY SNOW NOT TOTALLY OUT OF THE QUESTION FOR SOME AREAS AS
A WELL DEFINED TROWAL FEATURE EVOLVES. HOWEVER...TOP CIPS ANALOGS
WERE SHOWING GREATEST SUPPORT FOR SNOWFALL AMOUNTS TO REMAIN
BELOW WARNING CRITERIA.
&&
.LONG TERM /WEDNESDAY THROUGH SATURDAY/...
A BUILDING BLOCKING PATTERN CURRENTLY TAKING SHAPE OVER THE NORTH
ATLANTIC CAN BE SEEN WITHIN THE ECMWF 500MB HEMISPHERIC PLOT AND
CURRENT NEGATIVE PHASE OF THE NAO WHICH WILL MAKE FOR A SLOW-TO-MOVE
WEATHER PATTERN AT LEAST FROM MIDWEEK INTO THE WEEKEND. MODEL
ENSEMBLE FORECASTS FOR THE NAO INDEX SHOW THIS COULD PERSIST INTO
EARLY MARCH AS WELL. THE STORM SYSTEM WHICH WILL BE NEAR THE
FORECAST AREA ON WEDNESDAY WILL CONTINUE TO BRING CLOUDS AND
DIURNALLY INFLUENCED PRECIPITATION. AFTER THE INITIAL WARM FRONTAL
FORCED SLUG OF PRECIP PUSHES THROUGH TUESDAY NIGHT WE WILL SEE
MAINLY SCATTERED SHOWER ACTIVITY AS THE SYSTEM OCCLUDES TO OUR WEST
WEDNESDAY AND WEDNESDAY NIGHT WHICH THE 12Z GFS AND ECMWF AGREE
UPON.
MODELS SHOW THE SYSTEM WILL GET NUDGED EASTWARD THROUGH THURSDAY
WHERE A SLUG OF MOISTURE BENEATH THE UPPER LOW WILL LIKELY AGAIN
BRING RAIN AND SNOW ACROSS THE FORECAST AREA. P-TYPE WILL BE
DIURNALLY INFLUENCED AS DAYTIME TEMPS WILL RISE ABOVE FREEZING IN
MANY SPOTS DURING THE DAY WITH RAIN OCCURRING AND OVERNIGHT TEMPS
FALLING BACK TO NEAR OR BELOW FREEZING WHERE SNOW CAN BE EXPECTED.
FRIDAY AND SATURDAY WITH THE LOW NOW EAST OF THE LOWER LAKES SOME
COLDER AIR MOVES IN AND WITH LINGERING TROUGHINESS ALOFT WE KEPT A
CHANCE OF SNOW IN THE FORECAST. BY SATURDAY WE LOOK TO RETURN TO
BELOW NORMAL WHERE HIGHS MAY NOT BREAK ABOVE FREEZING.
&&
.AVIATION /15Z SUNDAY THROUGH THURSDAY/...
UPPER CUT OFF LOW TO CROSS THE REGION TODAY WITH MAINLY MVFR
CIGS/VSBY IN LIGHT SNOW AND OCCASIONAL BRIEF DROPS TO IFR VSBY IN
ANY STEADIER SNOW SHOWERS.
CONDITIONS WILL IMPROVE TO VFR 00Z-03Z AS DRYING ALOFT ASSOCIATED
WITH HIGH PRESSURE MOVING INTO THE REGION...SOME MVFR CIGS FOR
SOUTHERN TIER AND KROC-KSYR CORRIDOR.
OUTLOOK...
TONIGHT...VFR/MVFR WITH A CHANCE OF SNOW SHOWERS.
MONDAY...VFR.
TUESDAY THROUGH THURSDAY...MVFR WITH A CHANCE OF RAIN/SNOW.
&&
.MARINE...
A WEST WIND OVER LAKE ERIE UNDER CYCLONIC FLOW AND COLD AIR
ADVECTION ALOFT WILL STRENGTHEN TOWARDS 15 TO 20 KNOTS. A SMALL
CRAFT ADVISORY FOR LAKE ERIE WILL BE IN EFFECT THROUGH THE EARLY
EVENING. WINDS AND WAVES WILL ALSO CREATE SMALL CRAFT CONDITIONS ON
LAKE ONTARIO FROM SODUS BAY TO MEXICO BAY AND NORTH TO HENDERSON
BAY. THESE CONDITIONS WILL DEVELOP AROUND MID DAY AND PERSIST
THROUGH THE EVENING.
ON MONDAY AN AREA OF HIGH PRESSURE WILL CROSS THE LAKE WITH MINIMAL
WINDS AND WAVES ON THE LAKES.
&&
.BUF WATCHES/WARNINGS/ADVISORIES...
NY...NONE.
MARINE...SMALL CRAFT ADVISORY UNTIL 6 PM EST THIS EVENING FOR LEZ040-
041.
SMALL CRAFT ADVISORY UNTIL MIDNIGHT EST TONIGHT FOR
LOZ044-045.
&&
$$
SYNOPSIS...HITCHCOCK/WCH
NEAR TERM...HITCHCOCK/WCH
SHORT TERM...TMA
LONG TERM...SMITH
AVIATION...HITCHCOCK/WCH
MARINE...WCH
AREA FORECAST DISCUSSION
NWS NEWPORT/MOREHEAD CITY NC
1001 PM EST MON FEB 25 2013
.SYNOPSIS...
HIGH PRESSURE WILL MOVE OFF THE VIRGINIA COAST TONIGHT AS A WARM
FRONT APPROACHES FROM THE SOUTH. LOW PRESSURE WILL DEVELOP ON THE
WARM FRONT TUESDAY AND PASS TO THE WEST WITH ITS TRAILING COLD
FRONT CROSSING THE AREA TUESDAY NIGHT. NEARLY STATIONARY LOW
PRESSURE OVER THE NORTHEAST WILL CIRCULATE A WESTERLY FLOW OF COLD
AIR ACROSS THE REGION LATE WEDNESDAY THROUGH THE END OF THE WEEK
AND INTO THE WEEKEND.
&&
.NEAR TERM /UNTIL 6 AM TUESDAY MORNING/...
AS OF 945 PM MONDAY...REGIONAL MOSAIC RADAR SHOWS THAT THE
PRECIPITATION IS MAKING VERY LITTLE PROGRESS TO THE NORTH WITH THE
00Z MHX SOUNDING SHOWING PLENTIFUL DRY AIR BELOW ABOUT 600 MB WITH
MESOANALYSIS SHOWING THE PRECIPITABLE WATER IN THE 0.5 TO 0.7 INCH
RAIN WITH HIGHER VALUES STILL WELL SOUTH IN SOUTH CAROLINA WHERE
LIGHT PRECIP IS OCCURRING. LATEST RAP MODEL SHOWS COLUMN
MOISTENING WITH RAINFALL BECOMING WIDESPREAD BY AROUND 09Z OR 10Z
TUESDAY MORNING. TEMPERATURES ARE STARTING TO LEVEL OFF AND WILL
LIKELY REMAIN STEADY AND PERHAPS EVEN RISE TOWARD MORNING.
&&
.SHORT TERM /6 AM TUESDAY MORNING THROUGH 6 PM TUESDAY/...
VIGOROUS UPPER LOW OVER THE SOUTHERN PLAINS LIFTS NE THRU THE MID
MISSISSIPPI AND OHIO VALLEYS THRU MIDWEEK. ASSOCD UPPER TROF WILL
PUSH THRU THE SE STATES ON TUESDAY. PERIODS OF MODERATE TO HEAVY
RAIN EXPECTED WITH A STRONG 50 KT LOW LEVEL JET TRANSPORTING
ABUNDANT MOISTURE ACROSS THE AREA...PW`S INCREASE TO 1.5"...AND
GOOD DIFLUENCE ALOFT AHEAD OF THE UPPER LOW. WIDESPREAD 1 TO 2"
WILL BE POSSIBLE WITH LOCALLY HIGHER AMOUNTS WHICH MAY BRING MINOR
FLOODING CONCERNS...ESPECIALLY ACROSS URBAN AND LOW LYING AREAS.
THE WARM FRONT WILL LIFT N ACROSS THE AREA TUE AFTERNOON WHICH
WILL BRIEFLY PLACE ERN NC IN THE WARM SECTOR OF THE SYSTEM WHICH
MAY BRING JUST ENOUGH INSTABILITY TO PRODUCE A FEW THUNDERSTORMS.
WITH ABUNDANT SHEAR IN PLACE ANY THUNDERSTORMS THAT DEVELOP COULD
HAVE THE POTENTIAL TO PRODUCE DAMAGING WIND GUSTS AND AN ISOLATED
TORNADO THREAT.
&&
.LONG TERM /TUESDAY NIGHT THROUGH MONDAY/...
AS OF 325 PM MON...00Z ECMWF BETTER THAN 12Z GFS WHEN COMPARED WITH
HPC EXTENDED SURFACE GRAPHICS...SO AM USING THE ECMWF FOR THE
EXTENDED PORTION.
FRONTAL SYSTEM WILL VERY QUICKLY EXIT THE FORECAST AREA TUESDAY
EVENING. PRECIP WILL SHUT OFF FROM THE WEST BEFORE MIDNIGHT AS A
DRY WESTERLY FLOW SETS UP UNDERNEATH THE PARENT LOW TO THE NORTH.
AS A RESULT...LOWS TUE NIGHT AND HIGHS WED WILL AVERAGE AROUND 15
DEGREES ABOVE NORMAL. THE PARENT LOW TO THE NORTH WILL MOVE OUT
INTO THE ATLANTIC THU NIGHT AND FRIDAY WITH COOLER NORTHWEST FLOW
DEVELOPING...RETURNING TEMPS CLOSER TO NORMAL. WEEKEND LOOKS
UNSETTLED WITH DEEP UPPER TROF IN PLACE ALONG THE EAST COAST.
UPPER VORT CENTER ROUNDING BASE OF THE TROF WILL SPIN UP A SURFACE
LOW OFF THE COAST ON SATURDAY WHICH MOVES NORTHEAST AND DEEPENS
SATURDAY NIGHT INTO SUNDAY. MOST OF PRECIP WILL REMAIN OFFSHORE
SO KEPT JUST A SLIGHT CHANCE OVER THE EASTERN COUNTIES SATURDAY
NIGHT. BELIEVE TEMPS WILL BE JUST WARM ENOUGH TO KEEP PRECIP ALL
RAIN. DRY WEATHER SUNDAY NIGHT INTO EARLY NEXT WEEK AS UPPER TROF
LIFTS OUT AND LOW-LEVEL RIDGE BUILDS IN FROM THE WEST.
&&
.AVIATION /03Z TUESDAY THROUGH SATURDAY/...
SHORT TERM /THROUGH TUESDAY AFTERNOON/....
AS OF 655 PM MONDAY...VFR CONDITIONS CURRENTLY WITH SHIELD OF MID
TO HIGH LEVEL CLOUDINESS OVER THE MHX CWA. CEILINGS WILL SLOWLY
LOWER OVERNIGHT WITH NELY WINDS VEERING TO THE EAST BY MORNING.
CONDITIONS WILL QUICKLY DETERIORATE TUESDAY MORNING AS RAIN MOVES
INTO THE AREA...ALLOWING CEILINGS TO QUICKLY LOWER WITH LOW LEVEL
SATURATION. ANTICIPATE MVFR CEILINGS EARLY TUESDAY MORNING WITH
CIGS/VSBYS BECOMING IFR BY MID-MORNING. WINDS MAY BECOME GUSTY
AROUND THIS TIME AS THE SURFACE LOW APPROACHES FROM THE SW. WINDS
WILL CONTINUE TO VEER THROUGH THE AFTERNOON. IT SHOULD BE NOTED
THAT LOW LEVEL WIND SHEAR MAY BE QUITE STRONG IN THE MORNING OFF
THE DECK...AROUND 1KFT SELY WIND NEAR 30KTS. ALSO...SEVERE
THUNDERSTORM POTENTIAL SEEMS LIMITED. HOWEVER...STRONG WIND IS
POSSIBLE ASSOCIATED WITH HEAVIER PRECIPITATION. GIVEN THIS...CROSS
WIND MAY BE AN ISSUE FOR TAF SITES AS THE WINDS VEER THROUGHOUT
THE DAY.
LONG TERM /TUE NIGHT THRU SAT/...
AS OF 325 PM MON...CONVECTION ENDS QUICKLY FROM THE WEST TUESDAY
NIGHT AS FRONT MOVES OFF THE COAST. GENERALLY VFR THROUGH THE
EXTENDED PERIOD. ONLY PRECIP FORECAST IS A SLIGHT CHANCE SATURDAY
NIGHT BUT RAIN SHOULD STAY EAST OF TERMINALS.
&&
.MARINE...
AS OF 1000 PM MONDAY...HIGH PRESSURE WILL MOVE OFF OF THE VA COAST
AS A WARM FRONT MOVES SLOWLY NORTH INTO THE WATERS LATER TONIGHT.
ENE WINDS ARE ALREADY GUSTING CLOSE TO 20 KNOTS AT A FEW SPOTS AND
WINDS WILL INCREASE A BIT MORE AND WILL SHIFT TO THE SOUTHEAST
LATE TONIGHT. THIS STRENGTHENING FLOW WILL PRODUCE SEAS APPROACHING
ADVISORY LEVELS BY 12Z TUESDAY. CONDITIONS WILL CONTINUE TO
DETERIORATE TUESDAY MORNING AS STRONG LOW PRESSURE SYSTEM
APPROACHES THE WATERS...FLOWING BECOMING SE AND INCREASING TO
15-25KT WITH SEAS BUILDING TO 7-12FT BY TUE EVENING.
LONG TERM /TUE NIGHT THRU SAT/...
AS OF 325 PM MON...00Z ECMWF SURFACE FEATURES COMPARED BETTER
THAN 12Z GFS WITH HPC SURFACE GRAPHICS...SO USED ECMWF FOR THE
EXTENDED PORTION. COLD FRONT WILL EXIT THE COAST TUESDAY NIGHT
WITH FLOW BECOMING WESTERLY. FLOW WILL VEER FURTHER TO NORTHWEST
THURSDAY NIGHT AS LOW PRESSURE TO THE NORTH MOVES OFF THE COAST.
OFFSHORE FLOW WILL HELP KNOCK DOWN SEAS BELOW 6 FEET ALL MARINE
ZONES. NORTHWEST FLOW WILL CONTINUE INTO THE WEEKEND. LOW PRESSURE
DEVELOPS OFF THE SOUTHEAST COAST SATURDAY AND THEN MOVES
NORTHEAST. STRONGER NORTHWEST WINDS DEVELOP BUT NOT EXPECTED UNTIL
EARLY NEXT WEEK.
&&
.MHX WATCHES/WARNINGS/ADVISORIES...
NC...NONE.
MARINE...SMALL CRAFT ADVISORY FROM 8 AM TUESDAY TO 11 PM EST WEDNESDAY
FOR AMZ135.
SMALL CRAFT ADVISORY FROM 4 AM TUESDAY TO 11 PM EST WEDNESDAY
FOR AMZ150-152-154-156-158.
&&
$$
SYNOPSIS...BTC
NEAR TERM...CTC/BTC
SHORT TERM...BTC
LONG TERM...HSA
AVIATION...CTC/HSA
MARINE...CTC/BTC/HSA
AREA FORECAST DISCUSSION
NWS RALEIGH NC
955 PM EST MON FEB 25 2013
.SYNOPSIS...
A POTENT STORM SYSTEM WILL MOVE FROM THE LOWER MIDWEST INTO THE OHIO
VALLEY LATE TONIGHT AND TUESDAY. AN ASSOCIATED COLD FRONT WILL MOVE
EAST ACROSS CENTRAL NORTH CAROLINA TUESDAY NIGHT AND WEDNESDAY
MORNING.
&&
.NEAR TERM /TONIGHT/...
AS OF 955 PM MONDAY...
HIGH AND MID LEVEL CLOUDS HAVE RETURNED TO THE SECTIONS OF THE
WESTERN AND NORTHERN PIEDMONT THAT EARLIER THIS EVENING EXPERIENCED
PARTIAL CLEARING. LOW LEVEL NE WINDS CONTINUE TO FEED COOL DRY AIR
INTO THE REGION. LATEST SFC WET BULB ANALYSIS HAS WET BULB TEMPS
BELOW FREEZING ACROSS THE NORTHERN PIEDMONT AND THE NORTHERN COASTAL
PLAIN. NEAR TERM MODEL GUIDANCE HAS A GOOD HANDLE ON THIS SCENARIO
WITH SFC WET BULBS BELOW FREEZING ACROSS ALL OF THE PIEDMONT AND
MUCH OF THE COASTAL PLAIN BY MIDNIGHT THEN SLOWLY RETREAT NWD WITH
TIME.
MODEL TIMING OF THE MAIN PRECIP SHIELD CONTINUES TO SLOW/LAG PER
LATEST RADAR TRENDS. THE LATEST HRRR VERIFYING WELL WITH THE MAIN
PRECIP AREAS ACROSS THE LOWER MS VALLEY AND THE DEEP SOUTH BUT IS
OVEREMPHASIZING THE SPOTTY PRECIP OUT AHEAD THAT SHOULD BE OCCURRING
ACROSS THE SAVANNAH RIVER VALLEY. STILL APPEARS THAT PRECIP WILL
LIKELY NOT REACH OUR SOUTHERN COUNTIES UNTIL 2-4 AM...THEN EXPAND TO
THE NNE. BASED ON PRECIP TIMING AND CURRENT ANTECEDENT
CONDITIONS...ENOUGH COOLING MAY OCCUR IN THE LOWER LEVELS TO CAUSE
THE RAIN TO EITHER START OUT BRIEFLY OR MIX WITH FREEZING AND/OR
SLEET BEFORE TRANSITIONING TO ALL RAIN. WINTRY PRECIP AMOUNTS DON`T
APPEAR ENOUGH TO CAUSE ANY ACCUMULATION OR WIDESPREAD TRAVEL
PROBLEMS. SPS SHOULD COVER THE SCENARIO...IF IT OCCURS.
LITTLE CHANGE REQUIRED TO HOURLY TEMP/MIN TEMP FORECAST.
&&
.SHORT TERM /TUESDAY/...
AS OF 315 PM MONDAY...
OVERVIEW:
A POTENT UPPER LEVEL LOW AND ATTENDANT SFC LOW WILL TRACK NORTHEAST
INTO THE CENTRAL MS RIVER VALLEY BY 12Z TUE...AND INTO THE TN/OH
VALLEY BY 00Z WED. SOUTHWEST FLOW ALOFT IS EXPECTED DOWNSTREAM OVER
THE CAROLINAS.
PRECIPITATION CHANCES:
FORCING FOR PRECIP ON TUE WILL BE COMPRISED OF STRONG LOW-LEVEL WARM
ADVECTION...INCREASINGLY DIFFLUENT FLOW ALOFT DOWNSTREAM OF THE
AFOREMENTIONED UPPER LEVEL LOW PROGRESSING TOWARD THE OH VALLEY...
AND SMALL AMPLITUDE DISTURBANCES IN SW FLOW ALOFT. THE STRONGEST
UPPER LEVEL FORCING ASSOC/W SHORTWAVE ENERGY ROTATING AROUND THE
UPPER LOW SHOULD REMAIN LARGELY WEST/NW OF CENTRAL NC THROUGH THE
DAY TUE. THE MAIN CHANGE WITH THE FORECAST TODAY IS A SLOWER ONSET
TO PRECIP. THE SLOWER ONSET VIA THE 12Z MODEL RUNS AND SIMULATED REF
FORECASTS MAY BE DUE TO THE DRY ANTECEDENT AIRMASS IN PLACE AND MCS
ACTIVITY EXPECTED TO DEVELOP UPSTREAM OVER THE DEEP SOUTH LATE THIS
AFT/EVE INTO TONIGHT...WHICH COULD ALTER THE LOW-LEVEL HEIGHT/WIND
PATTERN OVER THE SOUTHEAST PRIOR TO THE DEVELOPMENT OF A STRONG SE
LLJ DURING THE DAY TUE. ALL MODEL GUIDANCE STILL GENERATES A GOOD
1.00-1.50" OF RAIN ACROSS THE AREA. DESPITE MCS ACTIVITY UPSTREAM
OVER THE DEEP SOUTH TONIGHT...A STRONG SOUTHEASTERLY LOW-LEVEL JET
/ATLANTIC MOISTURE FEED/ IS ANTICIPATED DURING THE DAY TUE...AND
SHOULD ALLOW FOR MODERATE TO OCCASIONALLY HEAVY RAIN ACROSS THE
AREA...ENHANCED BY THE PRESENCE OF MARGINAL MUCAPE ASSOC/W THE H85
WARM NOSE ATOP THE WEDGE...WHICH COULD RESULT IN ISOLD ELEVATED
CONVECTION BETWEEN 12-18 OR 12-21Z.
TEMPERATURES:
VERY CHALLENGING TEMPERATURE FCST. THE LATEST MODEL GUIDANCE STILL
APPEARS TO BE HAVING DIFFICULTY CAPTURING THE WEDGE EXPECTED TO
DEVELOP TUE MORNING. GIVEN DEWPOINTS IN THE LOWER/MID 20S AND
LOWER-THAN-EXPECTED TEMPERATURES THIS AFTERNOON...RANGING FROM THE
UPPER 30S TO LOWER 40S...EXPECT THAT THE STAGE IS SET FOR THE
DEVELOPMENT OF A STRONG CAD WEDGE AT THE ONSET OF PRECIP TUE
MORNING. WILL BASE THE TEMPERATURE FCST MORE-SO ON PATTERN
RECOGNITION IN THIS TYPE OF SETUP...WITH HIGHS ON TUE RANGING FROM
THE UPPER 30S/LOWER 40S IN THE TRIAD TO LOWER/MID 60S IN THE FAR SE
COASTAL PLAIN...IN CLOSER PROXIMITY TO A WAVE OF LOW PRESSURE
EXPECTED TO DEVELOP ALONG THE EASTERN PERIPHERY OF THE WEDGE.
SEVERE THREAT:
THE LATEST DAY 2 OUTLOOK FROM THE STORM PREDICTION CENTER INCLUDES
THE BULK OF CENTRAL NC (ASIDE FROM THE FAR N/NW PIEDMONT) IN A
SLIGHT RISK FOR SEVERE THUNDERSTORMS. HOWEVER...PATTERN RECOGNITION
AND PREVIOUS EXPERIENCE WOULD SUGGEST THAT MODEL GUIDANCE IS NOT
PROPERLY HANDLING THE WEDGE AIRMASS EXPECTED TO DEVELOP AND THAT THE
BAROCLINIC ZONE...ENSUING CYCLOGENESIS...AND BRIEF/NARROW WARM
SECTOR TUE AFTERNOON WILL LARGELY REMAIN EAST OF CENTRAL NC. AS A
RESULT...FEEL THAT THE BEST CHANCE OF SFC-BASED CONVECTION WILL
REMAIN OVER EASTERN (ESP. COASTAL) NC. IT IS AT LEAST POSSIBLE THAT
THE WEDGE FRONT COULD BRIEFLY MOVE FURTHER INLAND ACROSS THE
SOUTHEAST COASTAL PLAIN IN ASSOC/W STRENGTHENING SE LOW-LEVEL FLOW
TUE AFTERNOON...AND A LOW-END POTENTIAL FOR ISOLD SEVERE CONVECTION
OF THE HIGH SHEAR/LOW CAPE VARIETY CANNOT BE RULED OUT...PRIMARILY
IN CUMBERLAND...SAMPSON AND WAYNE COUNTIES. -VINCENT
&&
.LONG TERM /TUESDAY NIGHT THROUGH SUNDAY/...
AS OF 1150 AM MONDAY...
TUESDAY NIGHT...
AS THE STORM SYSTEM LIFTS NORTH INTO VA AND BEYOND... THE TRAILING
COLD FRONT IS FORECAST TO BE DELAYED UNTIL OVERNIGHT THROUGH 12Z
WED IN THE EAST. THE CAD BOUNDARY MAY ACTUALLY BE PULLED BACK
EASTWARD THROUGH THE COASTAL PLAIN AFTER THE LOW PRESSURE PASSES.
RESIDUAL CAD WILL PLAY A ROLE WITH LOW CEILINGS AND VISIBILITIES
WITH FOG AND EVEN SOME LIGHT DRIZZLE OVER THE PIEDMONT TRIAD REGION.
ANY ADDITIONAL QPF WOULD BE 0.01 OR TRACE AMOUNTS. SOME OF THE
WEATHER ASSOCIATED WITH THE RESIDUAL CAD MAY SPREAD BACK EASTWARD
OVER THE COASTAL PLAIN DURING THE OVERNIGHT OUT AHEAD OF THE MAIN
COLD FRONT THAT WILL ARRIVE LATER. THIS FRONT SHOULD PUSH EAST
THROUGH THE REGION BETWEEN 09Z-13Z OR SO... WITH GOOD MIXING OF DRY
AIR ALOFT DOWN TO THE SURFACE FINALLY BRINGING RAPID CLEARING.
EXPECT THIS RAPID CLEARING TO BEGIN IN THE LEE OF THE BLUE RIDGE
THEN SPREAD OUT OVER THE PIEDMONT AND EVENTUALLY THE COASTAL PLAIN
AS THE FRONT PASSES THROUGH. LOWS SHOULD BE HELD UP IN THE EAST AS
THE FRONT WILL BE DELAYED. THE TEMPS MAY DROP JUST BEFORE SUNRISE IN
THE WEST AS THE DRY AIR ARRIVES. LOWS GENERALLY 35-40 NW RANGING TO
NEAR 50 EAST.
WEDNESDAY-SUNDAY...
THE EUROPEAN OPERATIONAL MODEL ALONG WITH THE EC ENSEMBLE MEAN WERE
FAVORED IN THE MEDIUM RANGE PERIOD FROM WED-SUN. A PROGRESSIVELY
COLDER PATTERN IS EXPECTED OVER THE EASTERN UNITED STATES... WITH
THE COLDEST AIR EXPECTED TO ARRIVE TOWARD THE WEEKEND. THERE IS
STILL A LOW CHANCE OF A COASTAL STORM DEPENDING ON THE EXACT
POSITION/STRENGTH OF THE MID/UPPER LEVEL TROUGH THAT DEVELOPS OVER
THE EASTERN UNITED STATES. THE ARCTIC OSCILLATION AND THE NORTH
ATLANTIC OSCILLATION ARE FOREST TO BECOME STRONGLY NEGATIVE DAYS
6-10... WITH CORRESPONDING POSITIVE HEIGHT ANOMALIES SPREADING FROM
GREENLAND WESTWARD INTO FAR EASTERN CANADA IN THE HIGHER
LATITUDES... SUPPORTING COASTAL DEVELOPMENT OFF THE EAST COAST SAT
OR SUNDAY. JUST HOW FAR WEST THIS SYSTEM CAN DEVELOP WILL MEAN
EITHER DRY AND COLDER OR POSSIBLY WHITE AND COLDER OVER THE WEEKEND.
REGARDLESS... THE EASTERN TROUGH AND FORECAST HEIGHT ANOMALIES
SUPPORTS TEMPERATURES A GOOD 10-15 DEGREES BELOW NORMAL SAT-MON.
SENSIBLE WEATHER...
MILD AND PARTLY SUNNY WEDNESDAY...HIGHS 58-65. WESTERLY WINDS 10-20
MPH. PARTLY CLOUDY/PARTLY SUNNY THURSDAY AND FRIDAY. COLDER. LOWS IN
THE 20S TO AROUND 30. HIGHS 50-55 THURS...AND 45-50 FRI.
SAT-SUN...IMPORTANT PERIOD AS THE MID/UPPER TROUGH WILL DIG OVER THE
SOUTHERN APPALACHIANS...SOME COASTAL LOW POTENTIAL. WE WILL KEEP
FORECAST DRY FOR NOW...BUT THIS PATTERN WILL HAVE TO BE WATCHED.
COLD WITH LOWS IN THE 20S. HIGHS IN THE 40S (NEAR 50 SANDHILLS).
MONDAY...COLD AND DRY. LOWS IN THE 20S. HIGHS IN THE 40S.
&&
.AVIATION /00Z TUESDAY THROUGH SATURDAY/...
AS OF 700 PM MONDAY...
OBSERVATIONS MISSING FROM KRWI. A NOTAM HAS BEEN ISSUED AND THE KRWI
TAF WILL NOT BE AMENDED AFTER 03Z.
CURRENT VFR CONDITIONS WILL DETERIORATE LATER TONIGHT AS MOISTURE
INCREASES FROM THE SOUTHWEST. CIGS WILL BEGIN TO LOWER INTO THE MVFR
RANGE AS LIGHT RAIN OVERSPREADS THE REGION FROM SOUTHWEST TO
NORTHEAST...GENERALLY BETWEEN 09-12Z. THEN...AS HEAVIER RAIN MOVES
INTO THE REGION...CONDITIONS WILL FALL INTO THE IFR/LIFR RANGE
(GENERALLY BETWEEN 12-15Z)...WITH THESE CONDITIONS THEN EXPECTED TO
PREVAIL THROUGH THE END OF THE CURRENT TAF PERIOD (27/00Z). IN
ADDITION...A PERIOD OF SOUTHEASTERLY LOW-LEVEL WIND SHEAR IS
EXPECTED TUE MORNING INTO TUE AFTERNOON (MOST LIKELY BETWEEN 13-21Z)
AS A STRONG SOUTHEAST LLJ DEVELOPS ATOP A COLD AIR DAMMING WEDGE
(WHERE SURFACE WINDS WILL BE ENE). THERE WILL ALSO BE A SLIGHT
CHANCE OF A THUNDERSTORM TUESDAY AFTERNOON...WITH THE MOST LIKELY
LOCATIONS BEING ACROSS THE EAST (KFAY/KRWI).
OUTLOOK...IFR/LIFR CONDITIONS ASSOCIATED WITH THE RESIDUAL CAD WILL
LIKELY LINGER THROUGH TUESDAY EVENING/OVERNIGHT...BEFORE DRIER AIR
FINALLY FILTERS IN BEHIND A COLD FRONT THAT WILL MOVE THROUGH THE
AREA OVERNIGHT ON TUESDAY. VFR CONDITIONS ARE EXPECTED TO RETURN TO
THE AREA EARLY WEDNESDAY MORNING BEHIND THE DEPARTING FRONT AND THEN
PERSIST THROUGH THE REMAINDER OF THE WEEK.
&&
.RAH WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...VINCENT
NEAR TERM...WSS
SHORT TERM...VINCENT
LONG TERM...BADGETT
AVIATION...KRR
AREA FORECAST DISCUSSION
NWS NEWPORT/MOREHEAD CITY NC
654 PM EST MON FEB 25 2013
.SYNOPSIS...
HIGH PRESSURE WILL MOVE OFF THE VIRGINIA COAST THIS EVENING.
A WARM FRONT WILL APPROACH FROM THE SOUTH LATE TONIGHT. LOW
PRESSURE WILL DEVELOP ON THE WARM FRONT TUESDAY AND PASS TO
THE WEST WITH ITS TRAILING COLD FRONT CROSSING THE AREA TUESDAY
NIGHT. NEARLY STATIONARY LOW PRESSURE OVER THE NORTHEAST WILL
CIRCULATE A WESTERLY FLOW OF COLD AIR ACROSS THE REGION LATE
WEDNESDAY THROUGH THE END OF THE WEEK AND INTO THE WEEKEND.
&&
.NEAR TERM /UNTIL 6 AM TUESDAY MORNING/...
AS OF 650 PM MONDAY...CLOUDY SKIES AND COOL TEMPERATURES CONTINUE
OVER THE CWA THIS EVENING AS COOL HIGH PRESSURE EXTENDING
SOUTHEAST FROM ONTARIO CONTINUES TO WEDGE INTO EASTERN NORTH
CAROLINA. PRECIPITATION IS CURRENTLY LIMITED TO A SMALL PART OF
COASTAL SOUTH CAROLINA AS PRECIPITABLE WATER OVER OUR REGION AT
0.5 INCHES OR LESS. THE ATMOSPHERE WILL BEGIN TO MOISTEN LATER
TONIGHT AS FORECAST SOUNDINGS SHOW GOOD TRANSPORT OF ATLANTIC
MOISTURE INTO THE REGION BETWEEN 09Z AND 12Z. CURRENT FORECAST
BRINGS JUST SMALL POPS INTO THE REGION BETWEEN 06Z AND 09Z BEFORE
RAMPING THEM UP DURING THE EARLY HOURS OF TUESDAY AND THIS TREND
LOOKS FINE PER FORECAST SOUNDS AND THE RAP MODEL. FORECAST LOW
TEMPERATURES WILL LIKELY OCCUR THIS EVENING WITH STEADY OR
SLIGHTLY RISING TEMPERATURES OVERNIGHT.
&&
.SHORT TERM /6 AM TUESDAY MORNING THROUGH 6 PM TUESDAY/...
VIGOROUS UPPER LOW OVER THE SOUTHERN PLAINS LIFTS NE THRU THE MID
MISSISSIPPI AND OHIO VALLEYS THRU MIDWEEK. ASSOCD UPPER TROF WILL
PUSH THRU THE SE STATES ON TUESDAY. PERIODS OF MODERATE TO HEAVY
RAIN EXPECTED WITH A STRONG 50 KT LOW LEVEL JET TRANSPORTING
ABUNDANT MOISTURE ACROSS THE AREA...PW`S INCREASE TO 1.5"...AND
GOOD DIFLUENCE ALOFT AHEAD OF THE UPPER LOW. WIDESPREAD 1 TO 2"
WILL BE POSSIBLE WITH LOCALLY HIGHER AMOUNTS WHICH MAY BRING MINOR
FLOODING CONCERNS...ESPECIALLY ACROSS URBAN AND LOW LYING AREAS.
THE WARM FRONT WILL LIFT N ACROSS THE AREA TUE AFTERNOON WHICH
WILL BRIEFLY PLACE ERN NC IN THE WARM SECTOR OF THE SYSTEM WHICH
MAY BRING JUST ENOUGH INSTABILITY TO PRODUCE A FEW THUNDERSTORMS.
WITH ABUNDANT SHEAR IN PLACE ANY THUNDERSTORMS THAT DEVELOP COULD
HAVE THE POTENTIAL TO PRODUCE DAMAGING WIND GUSTS AND AN ISOLATED
TORNADO THREAT.
&&
.LONG TERM /TUESDAY NIGHT THROUGH MONDAY/...
AS OF 325 PM MON...00Z ECMWF BETTER THAN 12Z GFS WHEN COMPARED WITH
HPC EXTENDED SURFACE GRAPHICS...SO AM USING THE ECMWF FOR THE
EXTENDED PORTION.
FRONTAL SYSTEM WILL VERY QUICKLY EXIT THE FORECAST AREA TUESDAY
EVENING. PRECIP WILL SHUT OFF FROM THE WEST BEFORE MIDNIGHT AS A
DRY WESTERLY FLOW SETS UP UNDERNEATH THE PARENT LOW TO THE NORTH.
AS A RESULT...LOWS TUE NIGHT AND HIGHS WED WILL AVERAGE AROUND 15
DEGREES ABOVE NORMAL. THE PARENT LOW TO THE NORTH WILL MOVE OUT
INTO THE ATLANTIC THU NIGHT AND FRIDAY WITH COOLER NORTHWEST FLOW
DEVELOPING...RETURNING TEMPS CLOSER TO NORMAL. WEEKEND LOOKS
UNSETTLED WITH DEEP UPPER TROF IN PLACE ALONG THE EAST COAST.
UPPER VORT CENTER ROUNDING BASE OF THE TROF WILL SPIN UP A SURFACE
LOW OFF THE COAST ON SATURDAY WHICH MOVES NORTHEAST AND DEEPENS
SATURDAY NIGHT INTO SUNDAY. MOST OF PRECIP WILL REMAIN OFFSHORE
SO KEPT JUST A SLIGHT CHANCE OVER THE EASTERN COUNTIES SATURDAY
NIGHT. BELIEVE TEMPS WILL BE JUST WARM ENOUGH TO KEEP PRECIP ALL
RAIN. DRY WEATHER SUNDAY NIGHT INTO EARLY NEXT WEEK AS UPPER TROF
LIFTS OUT AND LOW-LEVEL RIDGE BUILDS IN FROM THE WEST.
&&
.AVIATION /00Z TUESDAY THROUGH SATURDAY/...
SHORT TERM /THROUGH TUESDAY AFTERNOON/....
AS OF 655 PM MONDAY...VFR CONDITIONS CURRENTLY WITH SHIELD OF MID
TO HIGH LEVEL CLOUDINESS OVER THE MHX CWA. CEILINGS WILL SLOWLY
LOWER OVERNIGHT WITH NELY WINDS VEERING TO THE EAST BY MORNING.
CONDITIONS WILL QUICKLY DETERIORATE TUESDAY MORNING AS RAIN MOVES
INTO THE AREA...ALLOWING CEILINGS TO QUICKLY LOWER WITH LOW LEVEL
SATURATION. ANTICIPATE MVFR CEILINGS EARLY TUESDAY MORNING WITH
CIGS/VSBYS BECOMING IFR BY MID-MORNING. WINDS MAY BECOME GUSTY
AROUND THIS TIME AS THE SURFACE LOW APPROACHES FROM THE SW. WINDS
WILL CONTINUE TO VEER THROUGH THE AFTERNOON. IT SHOULD BE NOTED
THAT LOW LEVEL WIND SHEAR MAY BE QUITE STRONG IN THE MORNING OFF
THE DECK...AROUND 1KFT SELY WIND NEAR 30KTS. ALSO...SEVERE
THUNDERSTORM POTENTIAL SEEMS LIMITED. HOWEVER...STRONG WIND IS
POSSIBLE ASSOCIATED WITH HEAVIER PRECIPITATION. GIVEN THIS...CROSS
WIND MAY BE AN ISSUE FOR TAF SITES AS THE WINDS VEER THROUGHOUT
THE DAY.
LONG TERM /TUE NIGHT THRU SAT/...
AS OF 325 PM MON...CONVECTION ENDS QUICKLY FROM THE WEST TUESDAY
NIGHT AS FRONT MOVES OFF THE COAST. GENERALLY VFR THROUGH THE
EXTENDED PERIOD. ONLY PRECIP FORECAST IS A SLIGHT CHANCE SATURDAY
NIGHT BUT RAIN SHOULD STAY EAST OF TERMINALS.
&&
.MARINE...
AS OF 655 PM MONDAY...HAVE CANCELLED THE CWA FOR THE MIDDLE WATERS
AND HAVE ISSUED A NEW SCA FOR ALL BUT THE ALBEMARLE SOUND...AS
WINDS/SEAS INCREASE LATER TONIGHT.
HIGH PRESSURE WILL MOVE OFF OF THE VA COAST THIS EVENING AS A
WARM FRONT MOVES SLOWLY NORTH INTO THE WATERS LATE. THE FLOW WILL
SHIFT TO THE SOUTHEAST AND INCREASE TO 15 TO 20 KT LATE TONIGHT.
THIS STRENGTHENING FLOW WILL PRODUCE SEAS APPROACHING ADVISORY
LEVELS BY 12Z TUESDAY. CONDITIONS WILL CONTINUE TO DETERIORATE
TUESDAY MORNING AS STRONG LOW PRESSURE SYSTEM APPROACHES THE
WATERS...FLOWING BECOMING SE AND INCREASING TO 15-25KT WITH SEAS
BUILDING TO 7-12FT BY TUE EVENING.
LONG TERM /TUE NIGHT THRU SAT/...
AS OF 325 PM MON...00Z ECMWF SURFACE FEATURES COMPARED BETTER
THAN 12Z GFS WITH HPC SURFACE GRAPHICS...SO USED ECMWF FOR THE
EXTENDED PORTION. COLD FRONT WILL EXIT THE COAST TUESDAY NIGHT
WITH FLOW BECOMING WESTERLY. FLOW WILL VEER FURTHER TO NORTHWEST
THURSDAY NIGHT AS LOW PRESSURE TO THE NORTH MOVES OFF THE COAST.
OFFSHORE FLOW WILL HELP KNOCK DOWN SEAS BELOW 6 FEET ALL MARINE
ZONES. NORTHWEST FLOW WILL CONTINUE INTO THE WEEKEND. LOW PRESSURE
DEVELOPS OFF THE SOUTHEAST COAST SATURDAY AND THEN MOVES
NORTHEAST. STRONGER NORTHWEST WINDS DEVELOP BUT NOT EXPECTED UNTIL
EARLY NEXT WEEK.
&&
.MHX WATCHES/WARNINGS/ADVISORIES...
NC...NONE.
MARINE...SMALL CRAFT ADVISORY FROM 8 AM TUESDAY TO 11 PM EST WEDNESDAY
FOR AMZ135.
SMALL CRAFT ADVISORY FROM 4 AM TUESDAY TO 11 PM EST WEDNESDAY
FOR AMZ150-152-154-156-158.
&&
$$
SYNOPSIS...BTC
NEAR TERM...CTC/BTC
SHORT TERM...BTC
LONG TERM...HSA
AVIATION...CTC/HSA/LEP
MARINE...CTC/BTC/HSA/LEP
AREA FORECAST DISCUSSION
NWS RALEIGH NC
645 AM EST SUN FEB 24 2013
.SYNOPSIS...
WEAK LOW PRESSURE MOVES AWAY FROM THE CAROLINA COAST AS HIGH
PRESSURE BUILDS INTO THE AREA TODAY. ANOTHER STORM SYSTEM MOVES INTO
THE REGION BY TUESDAY. THE LOW PRESSURE SYSTEM WILL INFLUENCE THE
WEATHER OF THE REGION INTO LATE IN THE WEEK.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 230 AM SUNDAY...
WHILE THE AXIS OF DEEPEST MOISTURE HAS FOR THE MOST PART SHIFTED
EAST AND DRIZZLE HAS BEEN MORE COMMON AROUND THE CWA ...A FEW
SHOWERS HAVE POPPED UP DURING THE PAST HOUR IN RESPONSE TO THE
APPROACHING UPPER TROUGH AXIS. THE HRRR HAS HAD A DECENT HANDLE ON
THIS EXPANDING PRECIP...AND WILL BE USED TO UPDATE THE NEAR TERM
FORECAST. WITH CONTINUED DRYING ALOFT COINCIDENT WITH THE TROUGH
PASSAGE...WILL BRING POPS TO AN END OVER THE NORTHERN COASTAL PLAIN
BY 12Z.
THE OTHER MAIN CONCERN IN THE NEAR TERM IS THE POTENTIAL FOR FOG.
THE BACK EDGE OF THE MAIN MID/HIGH CLOUD DECK HAS CLEARED THE
WESTERN PIEDMONT...BUT VISIBILITIES HAVE BEEN SLOW TO FALL BELOW 2SM
AT MOST SITES. A SECONDARY COLD FRONT IS WORKING ITS WAY ACROSS THE
MOUNTAINS...BUT AMPLE LOW LEVEL MOISTURE IN THE RESIDUAL WEDGE
AIRMASS WOULD SUPPORT DENSE FOG...MAINLY WEST OF RALEIGH. WE
WILL CONTINUE TO MONITOR THE OBSERVING SITES...BUT A DENSE FOG
ADVISORY MAY BE NEEDED BY 09-10Z.
LATER THIS MORNING..SKIES WILL CLEAR AND DRIER AIR WILL WORKS ITS
WAY ACROSS THE CWA. MODELS SHOW HE BETTER POST FRONTAL COLD
ADVECTION HOLDING OFF UNTIL AFTER 21Z...AND WITH FULL
INSOLATION...HIGHS SHOULD REBOUND RATHER NICELY. 1000-850MB
THICKNESSES REACHING THE 1330S THROUGH EARLY AFTERNOON SUPPORT HIGHS
IN THE UPPER 50S NORTH TO LOW/MID 60S SOUTH. HIGH PRESSURE WILL
BUILD INTO THE AREA TONIGHT...WITH THE RIDGE AXIS AND BEST POTENTIAL
FOR DECOUPLING ACROSS THE NORTHERN PIEDMONT/COASTAL PLAIN. LOWS
SHOULD FALL TO THE LOW TO MID 30S.
&&
.SHORT TERM /MONDAY THROUGH TUESDAY NIGHT/
AS OF 305 AM SUNDAY...
MONDAY AND MONDAY NIGHT...
COLD HIGH PRESSURE WILL SETTLE OVER NEW ENGLAND ON MONDAY...RIDGING
SOUTH INTO THE CAROLINAS. A 15-20M DROP IN 1000-850MB THICKNESSES
FROM SUNDAY TO MONDAY SUGGESTS HIGHS WILL STRUGGLE TO CLIMB OUT OF
THE LOW TO MID 50S...EVEN WITH A FAIR AMOUNT OF SUN THROUGH MIDDAY.
HIGH CLOUDS WILL BEGIN TO POUR INTO THE AREA MONDAY AFTERNOON AHEAD
OF A LOW PRESSURE SYSTEM EJECTING OUT OF THE SOUTHERN PLAINS. WARM
ADVECTION AND ISENTROPIC LIFT WILL INCREASE RAPIDLY MONDAY NIGHT
AHEAD OF A STRONG LOW LEVEL JET AND SURFACE-850MB WARM FRONT
EMANATING OFF OF THE GULF COAST REGION. WHILE FORECAST SOUNDINGS
SHOW QUITE A BIT OF DRY AIR BELOW 10K FT...STRENGTHENING UPPER
DIVERGENCE AND A BACKED LOW-LEVEL ATLANTIC MOISTURE FEED ASSOCIATED
WITH AN APPROACHING UPPER JET SHOULD QUICKLY OVERWHELM THE
AIRMASS...LEADING TO POPS RANGING FROM CATEGORICAL IN THE SOUTHWEST
TO LIKELY IN THE NORTHEAST AFTER MIDNIGHT. LOWS IN THE MID 30S TO
LOWER 40S. -SMITH
TUESDAY AND TUESDAY NIGHT...
DIFFLUENCE ALOFT EXISTS IN EARNEST TUESDAY AS THE UPPER LOW LIFTS TO
THE NORTHWEST OF THE STATE. GOOD 850MB THETA-E ADVECTION IS IN
PLACE...AND BY 18Z TUESDAY...PRECIPITABLE WATER VALUES ARE CLOSING
IN ON 1.5 INCHES...NEAR THE MAXIMUM OF THE CLIMATOLOGICAL ENVELOPE
FOR LATE FEBRUARY IN CENTRAL NORTH CAROLINA. DEEP AND BROAD SURFACE
LOW PRESSURE IN CONJUNCTION WITH MOISTURE AND LIFT SUGGESTS
WIDESPREAD RAIN IN A WEDGED AIR MASS INTO TUESDAY AFTERNOON...AND
SOME OF THE RAIN COULD BE LOCALLY HEAVY WITH...CURRENTLY...THE
HEAVIEST RAIN MOST LIKELY FOCUSED ALONG AND EAST OF U.S. 1 WHERE
850MB THETA-E RIDGING IS GREATEST DURING THE DAY...AND WHERE 850MB
CONVERGENCE LINGERS LONGEST. BASIN AVERAGE RAINFALL FOR THIS
FORECAST WILL BE AROUND 0.75 INCH TOWARD THE TRIAD...AND AROUND 1.5
INCHES SOUTH OF A LINE FROM KMEB TO KGSB...INCLUDING KFAY.
WHILE THE NAM FORECASTS A SURFACE LOW FARTHER WEST IN CENTRAL NORTH
CAROLINA TOWARD 00Z WEDNESDAY...THE GFS FORECASTS THE TRIPLE POINT
OF LOW PRESSURE SKIRTING THE FAR SOUTHEAST OF CENTRAL NORTH
CAROLINA...MORE TOWARD KFAY...KCTZ...AND KGSB. BUFR SOUNDINGS FROM
BOTH THE NAM AND THE GFS SHOW THE WEDGE TO BE FAIRLY STRONG AND
PROBABLY DIFFICULT TO DISLODGE...AND INSTABILITY FOR NOW APPEARS TO
BE LIMITED IN CENTRAL NORTH CAROLINA FOR THIS EVENT. DURING TUESDAY
AFTERNOON...THE GFS FORECASTS MIXED LAYER CAPE APPROACHING 700J/KG
OVER PARTS OF EASTERN SOUTH CAROLINA WHICH DIMINISHES AS THE TRIPLE
POINT MOVES NORTHEAST INTO THE WEDGE...SKIRTING THE FAR SOUTHERN
COASTAL PLAIN WITH VALUES UNDER 500J/KG AND LIFTED INDICES JUST
BELOW ZERO. IT SHOULD BE A NARROW WINDOW FOR ANY POTENTIAL OF STRONG
THUNDER IN THE SOUTHEAST...NEEDING TO BE COINCIDENT WITH ENOUGH
WARMTH IN VICINITY OF THE TRIPLE POINT AS THE DRY SLOT MOVES IN. GFS
BUFR SOUNDINGS SHOW THE POTENTIAL FOR STRONGER STORMS IS GREATER
TOWARD THE COAST...WHERE THE 850MB AND 925MB WINDS...ALONG WITH
1000-500MB LAPSE RATES...WILL BE BETTER LATE IN THE DAY. CONSIDERING
A SLIGHT CHANCE OF THUNDER ONLY FOR THE FAR SOUTHEAST PART OF
CENTRAL NORTH CAROLINA AS OF THIS WRITING NEAR THE CURRENTLY
EXPECTED TRACK OF THE SURFACE LOW COINCIDENT WITH THE HIGHEST
AFTERNOON TEMPERATURES IN CENTRAL NORTH CAROLINA.
IN TERMS OF TEMPERATURES...THERE SHOULD BE A STRONG GRADIENT IN
HIGHS TUESDAY...STRUGGLING TO RISE THROUGH THE 40S IN THE TRIAD...
TO THE LOWER OR EVEN POSSIBLY THE MID 60S IN THE FAR SOUTHEAST. THE
MORNING BUFR SOUNDING TOWARD KGSO TUESDAY SHOWS A PORTION OF THE
TEMPERATURE PROFILE BELOW ZERO ALOFT...BUT PARTIAL THICKNESSES NOTE
THE PRECIPITATION TYPE SHOULD BE ALL LIQUID. THE DRY SLOT AND
DIMINISHING MOISTURE OVERALL PROVIDE FOR CHANCES FOR PRECIPITATION
LOWERING QUICKLY FROM LATE TUESDAY AFTERNOON THROUGH TUESDAY
EVENING...BUT THE NAM MAY BE ON TO SOMETHING WITH ITS BUFR SOUNDINGS
IN SHOWING LOW-LEVEL MOISTURE AND CLOUDS SLOW TO ERODE IN AREAS WEST
OF U.S. 1 AND PARTICULARLY TOWARD THE TRIAD. WILL TREND TOWARD
WARMER OVERNIGHT LOWS TUESDAY NIGHT...MOSTLY IN THE 40S. -DJF
&&
.LONG TERM /WEDNESDAY THROUGH SATURDAY/...
AS OF 305 AM SUNDAY...
DURING THE MIDDLE AND END OF THE WEEK...THE LONG-TERM GUIDANCE IS
FAIRLY CONSISTENT IN FORECASTING AN UPPER LOW OVER OR NEAR THE LOWER
GREAT LAKES...GRADUALLY MIGRATING EAST. CONSISTENCY IS ALSO APPARENT
IN THE GUIDANCE...WITH SUBTLE TIMING DIFFERENCES...IN FORECASTING AT
LEAST A MODERATE MID-LEVEL SHORTWAVE MOVING ACROSS THE STATE
SOMETIME WEDNESDAY INTO WEDNESDAY EVENING ACCOMPANIED BY A SURFACE
TROUGH OR SECONDARY COLD FRONT. FROM THERE...A BROAD UPPER TROUGH
REMAINS OVER CENTRAL NORTH CAROLINA THROUGH THE END OF THIS CURRENT
LONG-TERM PERIOD...WITH MAINLY NORTHWEST...CONFLUENT FLOW ALOFT
DEVELOPING THURSDAY...AND THE TROUGH AXIS BUILDING BACK SOUTHWEST
AND INTRODUCING SOUTHWEST FLOW ALOFT ACROSS CENTRAL NORTH CAROLINA
BY THE END OF THE WORK WEEK. MUCH OF THE MEASURABLE GUIDANCE QPF IS
AWAY FROM CENTRAL NORTH CAROLINA TO THE NORTHWEST AND NORTH...
CREEPING CLOSEST WITH THE APPROACH AND PASSAGE OF BOTH THE STRONGER
MID-LEVEL SHORTWAVE AND THE SURFACE TROUGH WEDNESDAY INTO WEDNESDAY
EVENING.
THE 00Z GFS BUFR SOUNDING FOR KGSO NEAR 00Z THURSDAY IS INTERESTING
IN ITS STEEP LAPSE RATES AND POTENTIAL INSTABILITY INTO THE ICE
NUCLEATION REGION...AND DESPITE THE STABILITY OF THE ECMWF COARSE
MODEL SOUNDINGS FOR KGSO AND ELSEWHERE IN CENTRAL NORTH CAROLINA...
THE STRENGTH OF THE MID-LEVEL WAVE AHEAD OF THE MID-LEVEL TROUGH AND
ITS HEIGHT FALLS...ACCOMPANIED BY THE SURFACE FEATURE...WOULD SEEM
TO WARRANT AT LEAST A SLIGHT CHANCE OF A SHOWER WEDNESDAY AFTERNOON
INTO WEDNESDAY EVENING NORTH OF U.S. 64 AND ESPECIALLY FROM
THE TRIAD TOWARD THE VIRGINIA BORDER RELATIVE TO THE REST OF THE
AREA. PARTIAL THICKNESSES ARE SUPPORTIVE OF ALL LIQUID AT THAT TIME.
THE SAME SOUNDINGS ALSO SHOW SOME MID-LEVEL MOISTURE PRESENT LATE
WEDNESDAY NIGHT INTO THURSDAY MORNING...AND AS THE TROUGH AXIS
ROTATES THROUGH...THERE COULD BE A FEW FLURRIES THEN WITH NO
ANTICIPATED IMPACT. FOR THIS FORECAST...WILL INTRODUCE A SLIGHT
CHANCE OF RAIN SHOWERS WEDNESDAY AFTERNOON INTO WEDNESDAY EVENING
NORTH...WITH DRY CONDITIONS ELSEWHERE AND THEREAFTER FOR NOW.
WEDNESDAY AND THURSDAY SHOULD BE BREEZY DAYS IN A TIGHT SURFACE
GRADIENT BOTH AHEAD OF...AND ESPECIALLY BEHIND...THE SURFACE TROUGH
AND THICKNESS AND HEIGHT FALLS. FRIDAY SHOULD FEATURE SOMEWHAT
BREEZY CONDITIONS EARLY WITH MIXING BEFORE THE GRADIENT SLACKENS AS
LOW PRESSURE RETREATS OFFSHORE OF NEW ENGLAND AND THE MID-ATLANTIC.
THERE IS ALSO GOOD CONFIDENCE IN BELOW NORMAL HIGHS FOR THE END OF
THE WEEK INTO THE WEEKEND...LIKELY IN THE RANGE OF FIVE TO AROUND
TEN DEGREES BELOW WHAT SHOULD BE MID 50S TO AROUND 60. THE CONSENSUS
OF THE TEMPERATURE GUIDANCE...AND THE BLEND OF 1000-850MB
THICKNESSES BETWEEN THE GFS AND THE ECMWF...ARE BELOW MEX MOS
THURSDAY THROUGH SATURDAY. -DJF
&&
.AVIATION /12Z SUNDAY THROUGH THURSDAY/...
AS OF 645 AM SUNDAY...
LOW CLOUDS AND LIMITED VSBYS CONTINUE ACROSS CENTRAL NC THIS MORNING
AS A MURKY WEDGE AIRMASS LINGERS EAST OF THE MOUNTAINS. THE
DEPARTURE OF MID/HIGH CLOUDS HAS LEAD TO REDUCED VSBYS AT MANY
TERMINALS...THE LOWEST BEING IN THE TRIAD AT KGSO/KINT WHERE VSBYS
ARE LIFR. EAST OF THE TRIAD...VSBYS ARE ARE NOT AS LOW...BUT
CEILINGS ARE AT LIFR LEVELS. A SECONDARY COLD FRONT AND DRIER AIR
ARE BEGINNING TO PUSH EAST OF THE MOUNTAINS....AND VSBYS/CEILINGS
WILL BEGIN TO IMPROVE FROM WEST TO EAST BETWEEN 12Z AND 16Z. VFR
CONDITIONS ARE THEN EXPECTED FOR THE REMAINDER OF THE TAF
PERIOD...WITH NORTHWESTERLY WINDS TURNING TO NORTHEASTERLY OVERNIGHT
AS HIGH PRESSURE BUILDS INTO CENTRAL NC FROM THE NORTH.
OUTLOOK...
VFR CONDITIONS WILL CONTINUE TONIGHT AND MONDAY. A STORM
SYSTEM MOVING INTO THE REGION MONDAY NIGHT WILL BRING SUB-VFR
CONDITIONS WITH THE POTENTIAL FOR ISOLATED THUNDERSTORMS (KFAY/KRWI)
AND HEAVY RAIN TUESDAY. VFR CONDITIONS ARE THEN EXPECTED TO RETURN
BY TUESDAY NIGHT AND PERSIST THROUGH THE END OF THE WEEK.
&&
.RAH WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...DJF
NEAR TERM...SMITH
SHORT TERM...SMITH/DJF
LONG TERM...SMITH
AVIATION...SMITH
AREA FORECAST DISCUSSION
NWS RALEIGH NC
310 AM EST SUN FEB 24 2013
.SYNOPSIS...
WEAK LOW PRESSURE MOVES AWAY FROM THE CAROLINA COAST AS HIGH
PRESSURE BUILDS INTO THE AREA TODAY. ANOTHER STORM SYSTEM MOVES INTO
THE REGION BY TUESDAY. THE LOW PRESSURE SYSTEM WILL INFLUENCE THE
WEATHER OF THE REGION INTO LATE IN THE WEEK.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 230 AM SUNDAY...
WHILE THE AXIS OF DEEPEST MOISTURE HAS FOR THE MOST PART SHIFTED
EAST AND DRIZZLE HAS BEEN MORE COMMON AROUND THE CWA ...A FEW
SHOWERS HAVE POPPED UP DURING THE PAST HOUR IN RESPONSE TO THE
APPROACHING UPPER TROUGH AXIS. THE HRRR HAS HAD A DECENT HANDLE ON
THIS EXPANDING PRECIP...AND WILL BE USED TO UPDATE THE NEAR TERM
FORECAST. WITH CONTINUED DRYING ALOFT COINCIDENT WITH THE TROUGH
PASSAGE...WILL BRING POPS TO AN END OVER THE NORTHERN COASTAL PLAIN
BY 12Z.
THE OTHER MAIN CONCERN IN THE NEAR TERM IS THE POTENTIAL FOR FOG.
THE BACK EDGE OF THE MAIN MID/HIGH CLOUD DECK HAS CLEARED THE
WESTERN PIEDMONT...BUT VISIBILITIES HAVE BEEN SLOW TO FALL BELOW 2SM
AT MOST SITES. A SECONDARY COLD FRONT IS WORKING ITS WAY ACROSS THE
MOUNTAINS...BUT AMPLE LOW LEVEL MOISTURE IN THE RESIDUAL WEDGE
AIRMASS WOULD SUPPORT DENSE FOG...MAINLY WEST OF RALEIGH. WE
WILL CONTINUE TO MONITOR THE OBSERVING SITES...BUT A DENSE FOG
ADVISORY MAY BE NEEDED BY 09-10Z.
LATER THIS MORNING..SKIES WILL CLEAR AND DRIER AIR WILL WORKS ITS
WAY ACROSS THE CWA. MODELS SHOW HE BETTER POST FRONTAL COLD
ADVECTION HOLDING OFF UNTIL AFTER 21Z...AND WITH FULL
INSOLATION...HIGHS SHOULD REBOUND RATHER NICELY. 1000-850MB
THICKNESSES REACHING THE 1330S THROUGH EARLY AFTERNOON SUPPORT HIGHS
IN THE UPPER 50S NORTH TO LOW/MID 60S SOUTH. HIGH PRESSURE WILL
BUILD INTO THE AREA TONIGHT...WITH THE RIDGE AXIS AND BEST POTENTIAL
FOR DECOUPLING ACROSS THE NORTHERN PIEDMONT/COASTAL PLAIN. LOWS
SHOULD FALL TO THE LOW TO MID 30S.
&&
.SHORT TERM /MONDAY THROUGH TUESDAY NIGHT/
AS OF 305 AM SUNDAY...
MONDAY AND MONDAY NIGHT...
COLD HIGH PRESSURE WILL SETTLE OVER NEW ENGLAND ON MONDAY...RIDGING
SOUTH INTO THE CAROLINAS. A 15-20M DROP IN 1000-850MB THICKNESSES
FROM SUNDAY TO MONDAY SUGGESTS HIGHS WILL STRUGGLE TO CLIMB OUT OF
THE LOW TO MID 50S...EVEN WITH A FAIR AMOUNT OF SUN THROUGH MIDDAY.
HIGH CLOUDS WILL BEGIN TO POUR INTO THE AREA MONDAY AFTERNOON AHEAD
OF A LOW PRESSURE SYSTEM EJECTING OUT OF THE SOUTHERN PLAINS. WARM
ADVECTION AND ISENTROPIC LIFT WILL INCREASE RAPIDLY MONDAY NIGHT
AHEAD OF A STRONG LOW LEVEL JET AND SURFACE-850MB WARM FRONT
EMANATING OFF OF THE GULF COAST REGION. WHILE FORECAST SOUNDINGS
SHOW QUITE A BIT OF DRY AIR BELOW 10K FT...STRENGTHENING UPPER
DIVERGENCE AND A BACKED LOW-LEVEL ATLANTIC MOISTURE FEED ASSOCIATED
WITH AN APPROACHING UPPER JET SHOULD QUICKLY OVERWHELM THE
AIRMASS...LEADING TO POPS RANGING FROM CATEGORICAL IN THE SOUTHWEST
TO LIKELY IN THE NORTHEAST AFTER MIDNIGHT. LOWS IN THE MID 30S TO
LOWER 40S. -SMITH
TUESDAY AND TUESDAY NIGHT...
DIFFLUENCE ALOFT EXISTS IN EARNEST TUESDAY AS THE UPPER LOW LIFTS TO
THE NORTHWEST OF THE STATE. GOOD 850MB THETA-E ADVECTION IS IN
PLACE...AND BY 18Z TUESDAY...PRECIPITABLE WATER VALUES ARE CLOSING
IN ON 1.5 INCHES...NEAR THE MAXIMUM OF THE CLIMATOLOGICAL ENVELOPE
FOR LATE FEBRUARY IN CENTRAL NORTH CAROLINA. DEEP AND BROAD SURFACE
LOW PRESSURE IN CONJUNCTION WITH MOISTURE AND LIFT SUGGESTS
WIDESPREAD RAIN IN A WEDGED AIR MASS INTO TUESDAY AFTERNOON...AND
SOME OF THE RAIN COULD BE LOCALLY HEAVY WITH...CURRENTLY...THE
HEAVIEST RAIN MOST LIKELY FOCUSED ALONG AND EAST OF U.S. 1 WHERE
850MB THETA-E RIDGING IS GREATEST DURING THE DAY...AND WHERE 850MB
CONVERGENCE LINGERS LONGEST. BASIN AVERAGE RAINFALL FOR THIS
FORECAST WILL BE AROUND 0.75 INCH TOWARD THE TRIAD...AND AROUND 1.5
INCHES SOUTH OF A LINE FROM KMEB TO KGSB...INCLUDING KFAY.
WHILE THE NAM FORECASTS A SURFACE LOW FARTHER WEST IN CENTRAL NORTH
CAROLINA TOWARD 00Z WEDNESDAY...THE GFS FORECASTS THE TRIPLE POINT
OF LOW PRESSURE SKIRTING THE FAR SOUTHEAST OF CENTRAL NORTH
CAROLINA...MORE TOWARD KFAY...KCTZ...AND KGSB. BUFR SOUNDINGS FROM
BOTH THE NAM AND THE GFS SHOW THE WEDGE TO BE FAIRLY STRONG AND
PROBABLY DIFFICULT TO DISLODGE...AND INSTABILITY FOR NOW APPEARS TO
BE LIMITED IN CENTRAL NORTH CAROLINA FOR THIS EVENT. DURING TUESDAY
AFTERNOON...THE GFS FORECASTS MIXED LAYER CAPE APPROACHING 700J/KG
OVER PARTS OF EASTERN SOUTH CAROLINA WHICH DIMINISHES AS THE TRIPLE
POINT MOVES NORTHEAST INTO THE WEDGE...SKIRTING THE FAR SOUTHERN
COASTAL PLAIN WITH VALUES UNDER 500J/KG AND LIFTED INDICES JUST
BELOW ZERO. IT SHOULD BE A NARROW WINDOW FOR ANY POTENTIAL OF STRONG
THUNDER IN THE SOUTHEAST...NEEDING TO BE COINCIDENT WITH ENOUGH
WARMTH IN VICINITY OF THE TRIPLE POINT AS THE DRY SLOT MOVES IN. GFS
BUFR SOUNDINGS SHOW THE POTENTIAL FOR STRONGER STORMS IS GREATER
TOWARD THE COAST...WHERE THE 850MB AND 925MB WINDS...ALONG WITH
1000-500MB LAPSE RATES...WILL BE BETTER LATE IN THE DAY. CONSIDERING
A SLIGHT CHANCE OF THUNDER ONLY FOR THE FAR SOUTHEAST PART OF
CENTRAL NORTH CAROLINA AS OF THIS WRITING NEAR THE CURRENTLY
EXPECTED TRACK OF THE SURFACE LOW COINCIDENT WITH THE HIGHEST
AFTERNOON TEMPERATURES IN CENTRAL NORTH CAROLINA.
IN TERMS OF TEMPERATURES...THERE SHOULD BE A STRONG GRADIENT IN
HIGHS TUESDAY...STRUGGLING TO RISE THROUGH THE 40S IN THE TRIAD...
TO THE LOWER OR EVEN POSSIBLY THE MID 60S IN THE FAR SOUTHEAST. THE
MORNING BUFR SOUNDING TOWARD KGSO TUESDAY SHOWS A PORTION OF THE
TEMPERATURE PROFILE BELOW ZERO ALOFT...BUT PARTIAL THICKNESSES NOTE
THE PRECIPITATION TYPE SHOULD BE ALL LIQUID. THE DRY SLOT AND
DIMINISHING MOISTURE OVERALL PROVIDE FOR CHANCES FOR PRECIPITATION
LOWERING QUICKLY FROM LATE TUESDAY AFTERNOON THROUGH TUESDAY
EVENING...BUT THE NAM MAY BE ON TO SOMETHING WITH ITS BUFR SOUNDINGS
IN SHOWING LOW-LEVEL MOISTURE AND CLOUDS SLOW TO ERODE IN AREAS WEST
OF U.S. 1 AND PARTICULARLY TOWARD THE TRIAD. WILL TREND TOWARD
WARMER OVERNIGHT LOWS TUESDAY NIGHT...MOSTLY IN THE 40S. -DJF
&&
.LONG TERM /WEDNESDAY THROUGH SATURDAY/...
AS OF 305 AM SUNDAY...
DURING THE MIDDLE AND END OF THE WEEK...THE LONG-TERM GUIDANCE IS
FAIRLY CONSISTENT IN FORECASTING AN UPPER LOW OVER OR NEAR THE LOWER
GREAT LAKES...GRADUALLY MIGRATING EAST. CONSISTENCY IS ALSO APPARENT
IN THE GUIDANCE...WITH SUBTLE TIMING DIFFERENCES...IN FORECASTING AT
LEAST A MODERATE MID-LEVEL SHORTWAVE MOVING ACROSS THE STATE
SOMETIME WEDNESDAY INTO WEDNESDAY EVENING ACCOMPANIED BY A SURFACE
TROUGH OR SECONDARY COLD FRONT. FROM THERE...A BROAD UPPER TROUGH
REMAINS OVER CENTRAL NORTH CAROLINA THROUGH THE END OF THIS CURRENT
LONG-TERM PERIOD...WITH MAINLY NORTHWEST...CONFLUENT FLOW ALOFT
DEVELOPING THURSDAY...AND THE TROUGH AXIS BUILDING BACK SOUTHWEST
AND INTRODUCING SOUTHWEST FLOW ALOFT ACROSS CENTRAL NORTH CAROLINA
BY THE END OF THE WORK WEEK. MUCH OF THE MEASURABLE GUIDANCE QPF IS
AWAY FROM CENTRAL NORTH CAROLINA TO THE NORTHWEST AND NORTH...
CREEPING CLOSEST WITH THE APPROACH AND PASSAGE OF BOTH THE STRONGER
MID-LEVEL SHORTWAVE AND THE SURFACE TROUGH WEDNESDAY INTO WEDNESDAY
EVENING.
THE 00Z GFS BUFR SOUNDING FOR KGSO NEAR 00Z THURSDAY IS INTERESTING
IN ITS STEEP LAPSE RATES AND POTENTIAL INSTABILITY INTO THE ICE
NUCLEATION REGION...AND DESPITE THE STABILITY OF THE ECMWF COARSE
MODEL SOUNDINGS FOR KGSO AND ELSEWHERE IN CENTRAL NORTH CAROLINA...
THE STRENGTH OF THE MID-LEVEL WAVE AHEAD OF THE MID-LEVEL TROUGH AND
ITS HEIGHT FALLS...ACCOMPANIED BY THE SURFACE FEATURE...WOULD SEEM
TO WARRANT AT LEAST A SLIGHT CHANCE OF A SHOWER WEDNESDAY AFTERNOON
INTO WEDNESDAY EVENING NORTH OF U.S. 64 AND ESPECIALLY FROM
THE TRIAD TOWARD THE VIRGINIA BORDER RELATIVE TO THE REST OF THE
AREA. PARTIAL THICKNESSES ARE SUPPORTIVE OF ALL LIQUID AT THAT TIME.
THE SAME SOUNDINGS ALSO SHOW SOME MID-LEVEL MOISTURE PRESENT LATE
WEDNESDAY NIGHT INTO THURSDAY MORNING...AND AS THE TROUGH AXIS
ROTATES THROUGH...THERE COULD BE A FEW FLURRIES THEN WITH NO
ANTICIPATED IMPACT. FOR THIS FORECAST...WILL INTRODUCE A SLIGHT
CHANCE OF RAIN SHOWERS WEDNESDAY AFTERNOON INTO WEDNESDAY EVENING
NORTH...WITH DRY CONDITIONS ELSEWHERE AND THEREAFTER FOR NOW.
WEDNESDAY AND THURSDAY SHOULD BE BREEZY DAYS IN A TIGHT SURFACE
GRADIENT BOTH AHEAD OF...AND ESPECIALLY BEHIND...THE SURFACE TROUGH
AND THICKNESS AND HEIGHT FALLS. FRIDAY SHOULD FEATURE SOMEWHAT
BREEZY CONDITIONS EARLY WITH MIXING BEFORE THE GRADIENT SLACKENS AS
LOW PRESSURE RETREATS OFFSHORE OF NEW ENGLAND AND THE MID-ATLANTIC.
THERE IS ALSO GOOD CONFIDENCE IN BELOW NORMAL HIGHS FOR THE END OF
THE WEEK INTO THE WEEKEND...LIKELY IN THE RANGE OF FIVE TO AROUND
TEN DEGREES BELOW WHAT SHOULD BE MID 50S TO AROUND 60. THE CONSENSUS
OF THE TEMPERATURE GUIDANCE...AND THE BLEND OF 1000-850MB
THICKNESSES BETWEEN THE GFS AND THE ECMWF...ARE BELOW MEX MOS
THURSDAY THROUGH SATURDAY. -DJF
&&
.AVIATION /06Z SUNDAY THROUGH THURSDAY/...
AS OF 1240 AM SUNDAY...
LOW CLOUDS AND LIMITED VSBYS CONTINUE ACROSS CENTRAL NC THIS MORNING
AS A MURKY WEDGE AIRMASS LINGERS EAST OF THE MOUNTAINS. DRYING OF
THIS AIRMASS IS EXPECTED OVER THE NEXT 6-10 HOURS...FIRST IN THE MID
LEVELS THROUGH 09Z...THEN AT LOW LEVELS BY 12-15Z. AS THE MID
LEVELS DRY AND MID/HIGH CLOUDS MOVE EAST...VSBYS SHOULD CONTINUE TO
DROP TO IFR AND/OR LIFR LEVELS...WITH A FEW HOURS OF DENSE FOG
POSSIBLE FROM MAINLY KRDU TO KGSO/KINT AND SURROUNDING SITES IN THE
WESTERN PIEDMONT. EAST OF KRDU...LIGHT RAIN AND CEILINGS IN THE
200-500 FT RANGE ARE MORE LIKELY. DRIER LOW LEVEL AIR IS EXPECTED
TO ARRIVE WITH A NORTHWESTERLY WIND AT KGSO/KINT BY 10-12Z...WITH
CEILINGS AND VSBYS IMPROVING TO VFR FROM WEST TO EAST QUICKLY AFTER
12Z.
VFR CONDITIONS WILL THEN PREVAIL THROUGH THE TAF PERIOD.
OUTLOOK...
VFR CONDITIONS WILL CONTINUE TONIGHT AND MONDAY. A STORM
SYSTEM MOVING INTO THE REGION MONDAY NIGHT WILL BRING SUB-VFR
CONDITIONS WITH THE POTENTIAL FOR ISOLATED THUNDERSTORMS (KFAY/KRWI)
AND HEAVY RAIN TUESDAY. VFR CONDITIONS ARE THEN EXPECTED TO RETURN
BY TUESDAY NIGHT AND PERSIST THROUGH THE END OF THE WEEK.
&&
.RAH WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...DJF
NEAR TERM...SMITH
SHORT TERM...SMITH/DJF
LONG TERM...SMITH
AVIATION...SMITH
AREA FORECAST DISCUSSION
NWS RALEIGH NC
230 AM EST SUN FEB 24 2013
.SYNOPSIS...
WEAK LOW PRESSURE MOVES AWAY FROM THE CAROLINA COAST AS HIGH
PRESSURE BUILDS INTO THE AREA TODAY. ANOTHER STORM SYSTEM MOVES INTO
THE REGION BY TUESDAY. THE LOW PRESSURE SYSTEM WILL INFLUENCE THE
WEATHER OF THE REGION INTO LATE IN THE WEEK.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 230 AM SUNDAY...
WHILE THE AXIS OF DEEPEST MOISTURE HAS FOR THE MOST PART SHIFTED
EAST AND DRIZZLE HAS BEEN MORE COMMON AROUND THE CWA ...A FEW
SHOWERS HAVE POPPED UP DURING THE PAST HOUR IN RESPONSE TO THE
APPROACHING UPPER TROUGH AXIS. THE HRRR HAS HAD A DECENT HANDLE ON
THIS EXPANDING PRECIP...AND WILL BE USED TO UPDATE THE NEAR TERM
FORECAST. WITH CONTINUED DRYING ALOFT COINCIDENT WITH THE TROUGH
PASSAGE...WILL BRING POPS TO AN END OVER THE NORTHERN COASTAL PLAIN
BY 12Z.
THE OTHER MAIN CONCERN IN THE NEAR TERM IS THE POTENTIAL FOR FOG.
THE BACK EDGE OF THE MAIN MID/HIGH CLOUD DECK HAS CLEARED THE
WESTERN PIEDMONT...BUT VISIBILITIES HAVE BEEN SLOW TO FALL BELOW 2SM
AT MOST SITES. A SECONDARY COLD FRONT IS WORKING ITS WAY ACROSS THE
MOUNTAINS...BUT AMPLE LOW LEVEL MOISTURE IN THE RESIDUAL WEDGE
AIRMASS WOULD SUPPORT DENSE FOG...MAINLY WEST OF RALEIGH. WE
WILL CONTINUE TO MONITOR THE OBSERVING SITES...BUT A DENSE FOG
ADVISORY MAY BE NEEDED BY 09-10Z.
LATER THIS MORNING..SKIES WILL CLEAR AND DRIER AIR WILL WORKS ITS
WAY ACROSS THE CWA. MODELS SHOW HE BETTER POST FRONTAL COLD
ADVECTION HOLDING OFF UNTIL AFTER 21Z...AND WITH FULL
INSOLATION...HIGHS SHOULD REBOUND RATHER NICELY. 1000-850MB
THICKNESSES REACHING THE 1330S THROUGH EARLY AFTERNOON SUPPORT HIGHS
IN THE UPPER 50S NORTH TO LOW/MID 60S SOUTH. HIGH PRESSURE WILL
BUILD INTO THE AREA TONIGHT...WITH THE RIDGE AXIS AND BEST POTENTIAL
FOR DECOUPLING ACROSS THE NORTHERN PIEDMONT/COASTAL PLAIN. LOWS
SHOULD FALL TO THE LOW TO MID 30S.
&&
.SHORT TERM /MONDAY/
AS OF 232 PM SATURDAY...
RIDGING WILL BE IN PLACE ALONG THE EASTERN SEABOARD SUNDAY NIGHT
INTO MIDDAY MONDAY. THE SURFACE HIGH PRESSURE IS FORECAST TO BE OF
SUFFICIENT STRENGTH AND OF A FAVORABLE LOCATION TO DELIVER DRY AND
CHILLY AIR INTO OUR REGION SUNDAY NIGHT AND MONDAY... ENOUGH TO
SUPPORT THE EVOLUTION OF ANOTHER CAD EVENT IN THE FOLLOWING PERIOD
(SEE DISCUSSION BELOW). DEW POINTS ARE FORECAST TO FALL INTO THE
TEENS NORTHEAST... RANGING INTO THE LOWER TO MID 20S SOUTH MONDAY.
EXPECT MOSTLY CLEAR SKIES SUNDAY NIGHT AND EARLY MONDAY... THEN
INCREASING CLOUDINESS MONDAY. A CHANCE OF RAIN LATE IN THE SW. LOWS
25-32. A COOLER NE FLOW SUGGEST HIGHS MONDAY WILL NOT BE MUCH WARMER
THAN 50-55.
&&
.LONG TERM /MONDAY NIGHT THROUGH SATURDAY/...
AS OF 232 PM SATURDAY...
...SIGNIFICANT RAIN AND POSSIBLY SOME FLOODING MONDAY NIGHT INTO
TUESDAY...
MODELS WERE STILL ADVERTISING QUITE A SPREAD IN LOCATION/STRENGTH OF
THE MAIN MID-UPPER LOW THAT IS FORECAST TO DEVELOP OVER THE SOUTHERN
PLAINS AND GENERALLY MOVE NE TOWARD THE LOWER OHIO VALLEY AND
EASTERN GREAT LAKES TUESDAY. THE EVENTUAL TRACK/STRENGTH OF THE
SYSTEM WILL HAVE RAMIFICATIONS IN OUR FORECAST OF RAINFALL TIMING
AND AMOUNTS FOR LATE MONDAY THROUGH TUESDAY. THE OVERALL PATTERN
SUPPORTS ANOTHER CAD EVENT EVENT WITH THE VERY DRY AND CHILLY DRY
AIR RIDGE ALONG THE EASTERN SEABOARD INITIALLY BEFORE THE RAIN
DEVELOPS.
THE PATTERN OF A DEEPENING AND CLOSING OFF OF A MID/UPPER LOW SHOULD
LEAD TO A SLOWER SOLUTION THAN THE FASTER MODELS SUGGEST (NAM). THE
LATEST OPERATIONAL EUROPEAN MODEL APPEARS TO FALL MUCH IN LINE WITH
THE AVERAGE SREF ENSEMBLE SOLUTIONS AND WILL BE PREFERRED. IT
APPEARS THAT THE DRY AIR RIDGE ALONG THE EASTERN SEABOARD WILL HOLD
ON INTO MONDAY AFTERNOON... WITH RAIN DEVELOPING FROM THE SOUTH
REACHING THE SOUTHERN PIEDMONT BY 00/TUESDAY. STRONG ISENTROPIC LIFT
OF WARM MOIST AIR FROM THE GULF AND WESTERN ATLANTIC SHOULD BE
TAPPED AND DRIVEN UP AND OVER A WARM/COASTAL SURFACE FRONT THAT WILL
BE SLOWLY ADVANCING N-NW TOWARD OUR SE COASTAL PLAIN BY LATE MONDAY
NIGHT AND EARLY TUESDAY. IF THE EC SOLUTION PROVES CORRECT... THE
SLOWER TIMING AND THE NEGATIVE TILT OF THE MID/UPPER TROUGH SHOULD
ALLOW FOR INCREASING HEAVY RAIN POTENTIAL LATE MONDAY NIGHT AND
TUESDAY. THE FORECAST OF A SECONDARY LOW PRESSURE ALONG THE
RETREATING WARM FRONT SHOULD ALSO FOCUS THE HEAVY RAIN OVER CENTRAL
AND EASTERN NC. EVEN THE LATEST EC MAY BE DEVELOPING THE IMPORTANT
WAVE OF LOW PRESSURE TOO FAR WEST INTO THE PIEDMONT OF NC (DEEP IN
THE EXPECTED CAD REGION). WE PREFER THE EVOLUTION OF THE LOW TO BE
ALONG THE CAD BOUNDARY CLOSER TO THE COAST. IF THIS IS CORRECT...
OUR REGION WILL NOT GET IN THE WARM SECTOR AND THE CHANCE OF SURFACE
BASED THUNDER WILL BE NEARLY NIL. HOWEVER... ELEVATED THUNDERSTORMS
MAY DEVELOP AS THE MID-LEVEL LAPSE RATES ARE SUGGESTING.
THIS WILL BE AN IMPORTANT STORM SYSTEM FOR OUR REGION ESPECIALLY IN
REGARDS TO POTENTIALLY FOR HEAVY RAIN AND POSSIBLY SOME FLOODING. WE
WILL CONTINUE TO HIGHLIGHT THIS POTENTIAL IN THE HAZARDOUS WEATHER
OUTLOOK. QPF APPEARS THAT IT WILL NEED TO BE BEEFED UP TO AN AVERAGE
OF 1.5 INCHES... WITH 1-2 INCHES LIKELY. TIMING APPEARS TO BE MONDAY
NIGHT INTO TUESDAY... ENDING DURING TUESDAY AFTERNOON. THE SEVERE
THREAT APPEARS NIL AT THIS TIME... UNLESS FUTURE FORECASTS ARE FOR
LESS CAD... AND MORE IN THE WAY OF AN INLAND PENETRATING CAD
BOUNDARY. WINTER WEATHER APPEARS NIL AS WELL... AS THE MID LEVELS
ARE EXPECTED TO WARM SIGNIFICANTLY MONDAY NIGHT AND TUESDAY OUT
AHEAD OF THE MID/UPPER LOW. HOWEVER... THE CAD WILL POSE A RISK OF
BRIEF FREEZING RAIN MONDAY NIGHT IF THE TEMPERATURES WET BULB TO
30-31 OR 32. HOWEVER... IT APPEARS THAT THE CURRENT WET BULB
PROJECTIONS WILL BE IN THE 33-35 RANGE AT A MINIMUM BY 12Z/TUESDAY
SUGGESTING ALL RAIN EVEN IN THE HEART OF THE COLD AIR DAMMING OVER
THE PIEDMONT.
AFTER THIS SYSTEM LIFTS OUT LATE TUESDAY... A MILDER AND DRY
WESTERLY FLOW WILL FOLLOW WEDNESDAY AS THE STRONG LOW LIFTS OVER THE
GREAT LAKES. STRONG COOLING WILL FINALLY OCCUR WED NIGHT AND
THURSDAY AS THE H5 TROUGH DIGS OVER OUR REGION FROM THE MIDWEST. A
COLD AND LIKELY DRY NW FLOW PATTERN IS THEN EXPECTED FOR THE BALANCE
OF THE WEEK.
SENSIBLE WEATHER INCLUDES...
RAIN MONDAY NIGHT AND TUESDAY... POSSIBLY 1-2 INCHES. LOWS IN THE
30S TO AROUND 40 SE. HIGHS 40S NW TO LOWER 60S EAST TUESDAY. MILDER
AND DRY WED. LOWS IN THE UPPER 30S AND 40S. HIGHS IN THE MID 50S TO
MID 60S EAST. COLDER AND MOST LIKELY DRY LATER IN THE WEEK. WATCH
ANY DISTURBANCES IN THE NW FLOW HOWEVER... LOWS IN THE 20S AND LOWER
30S. HIGHS IN THE MID 40S TO MID 50S NW TO SE.
&&
.AVIATION /06Z SUNDAY THROUGH THURSDAY/...
AS OF 1240 AM SUNDAY...
LOW CLOUDS AND LIMITED VSBYS CONTINUE ACROSS CENTRAL NC THIS MORNING
AS A MURKY WEDGE AIRMASS LINGERS EAST OF THE MOUNTAINS. DRYING OF
THIS AIRMASS IS EXPECTED OVER THE NEXT 6-10 HOURS...FIRST IN THE MID
LEVELS THROUGH 09Z...THEN AT LOW LEVELS BY 12-15Z. AS THE MID
LEVELS DRY AND MID/HIGH CLOUDS MOVE EAST...VSBYS SHOULD CONTINUE TO
DROP TO IFR AND/OR LIFR LEVELS...WITH A FEW HOURS OF DENSE FOG
POSSIBLE FROM MAINLY KRDU TO KGSO/KINT AND SURROUNDING SITES IN THE
WESTERN PIEDMONT. EAST OF KRDU...LIGHT RAIN AND CEILINGS IN THE
200-500 FT RANGE ARE MORE LIKELY. DRIER LOW LEVEL AIR IS EXPECTED
TO ARRIVE WITH A NORTHWESTERLY WIND AT KGSO/KINT BY 10-12Z...WITH
CEILINGS AND VSBYS IMPROVING TO VFR FROM WEST TO EAST QUICKLY AFTER
12Z.
VFR CONDITIONS WILL THEN PREVAIL THROUGH THE TAF PERIOD.
OUTLOOK...
VFR CONDITIONS WILL CONTINUE TONIGHT AND MONDAY. A STORM
SYSTEM MOVING INTO THE REGION MONDAY NIGHT WILL BRING SUB-VFR
CONDITIONS WITH THE POTENTIAL FOR ISOLATED THUNDERSTORMS (KFAY/KRWI)
AND HEAVY RAIN TUESDAY. VFR CONDITIONS ARE THEN EXPECTED TO RETURN
BY TUESDAY NIGHT AND PERSIST THROUGH THE END OF THE WEEK.
&&
.RAH WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...DJF
NEAR TERM...SMITH
SHORT TERM...BADGETT
LONG TERM...BADGETT
AVIATION...SMITH
AREA FORECAST DISCUSSION
NWS GRAND FORKS ND
1112 AM CST SUN FEB 24 2013
.DISCUSSION...
FOG WAS DISSIPATING AT A GOOD CLIP THIS MORNING OVER THE MN SIDE.
WILL CANCEL FOG ADVISORY FOR THE AREA. HOWEVER WILL HAVE PATCHY FOG
FOR THE REST OF THE MORNING ON THE MN SIDE.
FEW RETURNS ON RADAR WITH A COUPLE OBS SITES REPORTED LIGHT SNOW
OVER THE FAR NORTHWEST ZONES. WILL KEEP FLURRIES FOR THIS AFTERNOON
MAINLY ON THE ND SIDE.
ESSENTIALLY LITTLE CHANGE TO TEMPS FOR TODAY.
&&
.PREVIOUS DISCUSSION.../ISSUED 420 AM CST SUN FEB 24 2013/
CHALLENGE FOR THE FORECAST INCLUDES FOG THIS MORNING AND ITS AFFECT
TODAY ON TEMPS IN NW MN. OTHERWISE TEMPS AND CLOUD THE MAIN
CHALLENGE FOR THE FIRST PART OF THE WEEK. MODELS IN GOOD AGREEMENT
AND USED A BLEND FOR THE FORECAST PACKAGE.
HAVE INHERITED FOG ADVISORY AND NEED TO EXPEND NORTH AS OBS AT CKN AND
HCO ARE QUARTER MILE. HRRR SHOWS LOW VSBYS THRU 18Z SO WILL EXTEND IN
TIME ALSO. STRATUS DECK WILL LIFT AS 925 WINDS INCREASE AND IMPROVE
MIXING THROUGH THE MORNING HOURS SIMILAR TO SATURDAY MORNING. WEAK
SFC LOW IS EXPECTED TO CONTINUE TO MOVE ACROSS ND TODAY AND SLOWLY
WEAKEN AS LIGHT SNOW COVERAGE DIMINISHES. KEPT THE CHC POPS IN THE
DVL BASIN THRU NOON THEN WENT FLURRIES FOR THIS AFTERNOON.
MON AND TUE ARE DRY WITH CONCERN BEING CLOUD COVER AND ITS EFFECTS
ON TEMPS. 500MB SPLIT FLOW WITH SOUTHERN PLAINS CUTOFF STORM SYSTEM
AND RIDGING BUILDING INTO THE NORTHERN PLAINS WILL GIVE MORE SUN
THAN CLOUDS WITH 925 TEMPS INCREASING TO NEAR 0 BY 00Z TUE WILL GIVE
ABOVE NORMAL TEMPS TO THE AREA.
LONG TERM (WEDNESDAY-SATURDAY)...
MODELS AGREE THAT AN UPPER RIDGE
WILL BUILD ACROSS THE WESTERN CONUS THROUGH THE PERIOD. THIS WILL
PLACE A SFC RIDGE ACROSS THE REGION AND LEAD TO DRY WEATHER.
TEMPERATURES WILL BE NEAR NORMAL.
&&
.AVIATION...
FOG WAS LIFTING ACROSS THE NORTHWEST MN. SCATTERED MVFR TO IFR WAS
MOVING INTO THE WESTERN ZONES. EXPECT CIGS IN THE WEST TO RISE TO
AROUND 2 THOUSAND FT THIS AFTERNOON.
&&
.FGF WATCHES/WARNINGS/ADVISORIES...
ND...NONE.
MN...NONE.
&&
$$
HOPPES
AREA FORECAST DISCUSSION
NWS GRAND FORKS ND
420 AM CST SUN FEB 24 2013
.SHORT TERM...
CHALLENGE FOR THE FORECAST INCLUDES FOG THIS MORNING AND ITS AFFECT
TODAY ON TEMPS IN NW MN. OTHERWISE TEMPS AND CLOUD THE MAIN
CHALLENGE FOR THE FIRST PART OF THE WEEK. MODELS IN GOOD AGREEMENT
AND USED A BLEND FOR THE FORECAST PACKAGE.
HAVE INHERITED FOG ADVSY AND NEED TO EXPEND NORTH AS OBS AT CRK AND
HCO ARE QUARTER MILE. HRRR SHOWS LOW VSBYS THRU 18Z SO WILL EXTEND IN
TIME ALSO. STRATUS DECK WILL LIFT AS 925 WINDS INCREASE AND IMPROVE
MIXING THROUGH THE MORNING HOURS SIMILAR TO SATURDAY MORNING. WEAK
SFC LOW IS EXPECTED TO CONTINUE TO MOVE ACROSS ND TODAY AND SLOWLY
WEAKEN AS LIGHT SNOW COVERAGE DIMINISHES. KEPT THE CHC POPS IN THE
DVL BSN THRU NOON THEN WENT FLURRIES FOR THIS AFTERNOON.
MON AND TUE ARE DRY WITH CONCERN BEING CLOUD COVER AND ITS EFFECTS
ON TEMPS. 500MB SPLIT FLOW WITH SOUTHERN PLAINS CUTOFF STORM SYSTEM
AND RIDGING BUILDING INTO THE NORTHERN PLAINS WILL GIVE MORE SUN
THAN CLOUDS WITH 925 TEMPS INCREASING TO NEAR 0 BY 00Z TUE WILL GIVE
ABOVE NORMAL TEMPS TO THE AREA.
.LONG TERM (WEDNESDAY-SATURDAY)...
MODELS AGREE THAT AN UPPER RIDGE
WILL BUILD ACROSS THE WESTERN CONUS THROUGH THE PERIOD. THIS WILL
PLACE A SFC RIDGE ACROSS THE REGION AND LEAD TO DRY WEATHER.
TEMPERATURES WILL BE NEAR NORMAL.
&&
.AVIATION...
ANOTHER MORNING OF FG ACROSS ALL TAF SITES EXCEPT DVL. INTERMITTENT 1/4
VSBYS TO LAST THROUGH EARLY MORNING WITH IFR CIGS/VSBYS TO IMPROVE
LATE MORNING TO EARLY AFTN.
&&
.FGF WATCHES/WARNINGS/ADVISORIES...
ND...FREEZING FOG ADVISORY UNTIL NOON CST TODAY FOR NDZ053.
MN...FREEZING FOG ADVISORY UNTIL NOON CST TODAY FOR MNZ001>009-
013>017-022>024-027>032-040.
&&
$$
JK/TG
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
1239 PM EST SUN FEB 24 2013
.SYNOPSIS...
AN UPPER LEVEL LOW OVER THE GREAT LAKES WILL SLIDE EAST ACROSS
UPSTATE NEW YORK TODAY. A RIDGE OF HIGH PRESSURE WILL BUILD OVER
PENNSYLVANIA ON MONDAY. A STORM SYSTEM OVER THE PLAINS WILL TRACK
NORTHEAST INTO PENNSYLVANIA ON TUESDAY. THE PARENT UPPER LOW WILL
REMAIN OVER THE NORTHEAST CONUS THROUGH THE END OF THE WEEK.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
FEW FLURRIES DOWN TO THE DUBOIS AREA. CURRENT FCST GOOD.
EARLIER DISCUSSION BELOW.
DRIER WESTERLY FLOW WORKING INTO CENTRAL PA EARLY THIS AM BEHIND
OCCLUDED FRONT. HOWEVER...ABUNDANT LOW LVL MOISTURE AND A CALM
WIND AHEAD OF THIS BOUNDARY CONTINUES TO RESULT IN AREAS OF FOG
ACROSS THE SUSQ VALLEY AT 11Z. LATEST 3KM HRRR SUGGESTS FOG WILL
LIFT ACROSS THE EASTERN ZONES BY ARND 13Z...AS DRIER AIR ARRIVES.
FOCUS THEN SHIFTS TOWARD UPPER LOW SLIDING EAST FROM THE GRT LKS.
LG SCALE FORCING AHEAD OF THIS FEATURE SHOULD SUPPORT SCT -SHSN
ACROSS THE W MTNS LATER TODAY...WHICH WILL LIKELY DUST THE GROUND
OVER THE HIGHER TERRAIN.
CAA AND PLENTY OF STRATO-CU SHOULD KEEP TEMPS FROM RISING MUCH
TODAY...THE EXCEPTION BEING THE LOWER SUSQ VALLEY...WHERE
DRYING/DOWNSLOPING FLOW SHOULD YIELD PTSUNNY SKIES AND TEMPS
REACHING THE M40S. A TIGHTENING PRES GRADIENT BTWN HIGH PRES OVR
THE MIDWEST AND INTENSIFYING LOW SOUTH OF NEW ENG WILL RESULT IN
AN INCREASINGLY GUSTY WNW WIND ACROSS CENTRAL PA TODAY. BUFKIT MDL
SOUNDINGS INDICATE THERE WILL BE GUSTS ARND 25KTS BY MID AFTN.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH 6 PM MONDAY/...
SCT SNOW SHOWERS ACROSS THE NW MTNS SHOULD TAPER OFF THIS
EVENING...AS UPPER LOW LIFTS OUT AND INVERSION HGTS FALL. EXPECT A
GENERAL CLEARING TREND TONIGHT...AS SFC HIGH BUILDS TOWARD PA FROM
THE MIDWEST. HOWEVER...MDL SOUNDINGS INDICATE LOW LVL MOISTURE
TRAPPED BENEATH INVERSION WILL REMAIN BANKED AGAINST THE NW MTNS
THRU MUCH OF THE NIGHT.
HIGH PRES SHOULD PROVIDE MOST OF THE REGION WITH SUNNY SKIES AND
LGT WINDS MONDAY WITH TEMPS NEAR SEASONAL LEVELS.
&&
.LONG TERM /MONDAY NIGHT THROUGH SATURDAY/...
ALL MED RANGE GUIDANCE INDICATING UPPER LOW OVR THE MISS VALLEY
WILL LIFT NE TOWARD PA ON TUESDAY...PROVIDING INCREASING
CONFIDENCE IN A FAIRLY SIGNIFICANT PRECIP EVENT FOR PA WITH GEFS
MEAN QPF BTWN 0.5 AND 1 INCH. BOTH ECMWF ENSEMBLE MEAN AND GEFS MEAN
SOLUTIONS TRACK A PRIMARY SFC LOW TO OUR WEST WITH A SECONDARY
LIFTING THRU EASTERN PA. THIS SCENARIO WOULD LIKELY RESULT IN SOME
WARMER AIR WORKING IN ALOFT...RESULTING IN MIXED PRECIP TYPES.
ECMWF ENS MEAN 850 TEMPS SUPPORT THE BEST CHC OF WINTRY PRECIP OVR
THE N MTNS WITH RAIN MOST LIKELY IN THE SE.
THE BULK OF THE PRECIP SHOULD BE OVER BY WED...AS SERLY LL JET AND
PLUME OF ANOMALOUS PWATS LIFTS NORTH OF PA. HOWEVER...UNSETTLED/COOL
WX SEEMS LIKELY THRU THE END OF NEXT WEEK WITH MED RANGE MDL DATA
ALL KEEPING UPPER LOW IN THE VICINITY OF PA. ALTHOUGH AIR MASS
DOESN/T LOOK INITIALLY COLD ENOUGH FOR LAKE EFFECT...A
DEEP...MOIST NWRLY FLOW SHOULD YIELD PERSISTENT UPSLOPE SNOW
SHOWERS ACROSS THE W MTNS WED-FRI. LIGHT ACCUMS SEEM PROBABLE ESP
AT NIGHT. DAYTIME TEMPS WED-THU SHOULD GET ABV FREEZING EVERYWHERE
BASED ON ECMWF ENS MEAN 8H TEMPS.
&&
.AVIATION /18Z SUNDAY THROUGH FRIDAY/...
TYPICAL POST-COLD-FRONT NORTHWEST FLOW SET UP ACROSS THE
REGION...WITH MVFR TO OCCASIONAL IFR CONDITIONS ACROSS THE
MOUNTAINS IN LOW CEILINGS AND SNOW SHOWERS...AND MAINLY VFR
ELSEWHERE. EXPECT THIS PATTERN TO CONTINUE THE REST OF THE
AFTERNOON AND MUCH OF THE TONIGHT...ALTHOUGH LIKELY TO SEE A
SLOW DIMINISHING OF SNOW SHOWER ACTIVITY IN THE WEST AS DRY AIR
MOVES INTO THE REGION.
WINDS WILL REMAIN BREEZY THROUGH THE AFTERNOON...WITH 10 TO 20
KNOT WINDS COMMON...SLOWLY DIMINISHING THIS EVENING.
VFR CONDITIONS FOR MONDAY ALL AREAS AS HIGH PRESSURE MOVES ACROSS
THE REGION.
ANOTHER SIGNIFICANT WEATHER SYSTEM WILL BRING LOWERING CONDITIONS
AND MIXED PRECIPITATION TO CENTRAL PENNSYLVANIA BEGINNING
TUESDAY...LASTING INTO WEDNESDAY.
OUTLOOK...
MON...MAINLY VFR.
TUE...DETERIORATING CONDITIONS FROM SW TO NE. MVFR TO IFR.
WED...CONTINUED MIXED PRECIPITATION...MVFR TO IFR.
THU...CONTINUING RAIN AND SNOW SHOWERS...REDUCED CIGS AND VSBYS
ESPECIALLY WEST AND CENTRAL.
&&
.CTP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...FITZGERALD
NEAR TERM...FITZGERALD/MARTIN
SHORT TERM...FITZGERALD
LONG TERM...FITZGERALD
AVIATION...JUNG/RXR
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
1041 AM EST SUN FEB 24 2013
.SYNOPSIS...
AN UPPER LEVEL LOW OVER THE GREAT LAKES WILL SLIDE EAST ACROSS
UPSTATE NEW YORK TODAY. A RIDGE OF HIGH PRESSURE WILL BUILD OVER
PENNSYLVANIA ON MONDAY. A STORM SYSTEM OVER THE PLAINS WILL TRACK
NORTHEAST INTO PENNSYLVANIA ON TUESDAY. THE PARENT UPPER LOW WILL
REMAIN OVER THE NORTHEAST CONUS THROUGH THE END OF THE WEEK.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
UPDATED PACKAGE. CURRENT FCST GOOD...SOME SNOW SHOWERS WORKING
IN LATER ACROSS THE NORTH...SOME SUN EARLY THIS MORNING.
EARLIER DISCUSSION BELOW.
DRIER WESTERLY FLOW WORKING INTO CENTRAL PA EARLY THIS AM BEHIND
OCCLUDED FRONT. HOWEVER...ABUNDANT LOW LVL MOISTURE AND A CALM
WIND AHEAD OF THIS BOUNDARY CONTINUES TO RESULT IN AREAS OF FOG
ACROSS THE SUSQ VALLEY AT 11Z. LATEST 3KM HRRR SUGGESTS FOG WILL
LIFT ACROSS THE EASTERN ZONES BY ARND 13Z...AS DRIER AIR ARRIVES.
FOCUS THEN SHIFTS TOWARD UPPER LOW SLIDING EAST FROM THE GRT LKS.
LG SCALE FORCING AHEAD OF THIS FEATURE SHOULD SUPPORT SCT -SHSN
ACROSS THE W MTNS LATER TODAY...WHICH WILL LIKELY DUST THE GROUND
OVER THE HIGHER TERRAIN.
CAA AND PLENTY OF STRATO-CU SHOULD KEEP TEMPS FROM RISING MUCH
TODAY...THE EXCEPTION BEING THE LOWER SUSQ VALLEY...WHERE
DRYING/DOWNSLOPING FLOW SHOULD YIELD PTSUNNY SKIES AND TEMPS
REACHING THE M40S. A TIGHTENING PRES GRADIENT BTWN HIGH PRES OVR
THE MIDWEST AND INTENSIFYING LOW SOUTH OF NEW ENG WILL RESULT IN
AN INCREASINGLY GUSTY WNW WIND ACROSS CENTRAL PA TODAY. BUFKIT MDL
SOUNDINGS INDICATE THERE WILL BE GUSTS ARND 25KTS BY MID AFTN.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH 6 PM MONDAY/...
SCT SNOW SHOWERS ACROSS THE NW MTNS SHOULD TAPER OFF THIS
EVENING...AS UPPER LOW LIFTS OUT AND INVERSION HGTS FALL. EXPECT A
GENERAL CLEARING TREND TONIGHT...AS SFC HIGH BUILDS TOWARD PA FROM
THE MIDWEST. HOWEVER...MDL SOUNDINGS INDICATE LOW LVL MOISTURE
TRAPPED BENEATH INVERSION WILL REMAIN BANKED AGAINST THE NW MTNS
THRU MUCH OF THE NIGHT.
HIGH PRES SHOULD PROVIDE MOST OF THE REGION WITH SUNNY SKIES AND
LGT WINDS MONDAY WITH TEMPS NEAR SEASONAL LEVELS.
&&
.LONG TERM /MONDAY NIGHT THROUGH SATURDAY/...
ALL MED RANGE GUIDANCE INDICATING UPPER LOW OVR THE MISS VALLEY
WILL LIFT NE TOWARD PA ON TUESDAY...PROVIDING INCREASING
CONFIDENCE IN A FAIRLY SIGNIFICANT PRECIP EVENT FOR PA WITH GEFS
MEAN QPF BTWN 0.5 AND 1 INCH. BOTH ECMWF ENSEMBLE MEAN AND GEFS MEAN
SOLUTIONS TRACK A PRIMARY SFC LOW TO OUR WEST WITH A SECONDARY
LIFTING THRU EASTERN PA. THIS SCENARIO WOULD LIKELY RESULT IN SOME
WARMER AIR WORKING IN ALOFT...RESULTING IN MIXED PRECIP TYPES.
ECMWF ENS MEAN 850 TEMPS SUPPORT THE BEST CHC OF WINTRY PRECIP OVR
THE N MTNS WITH RAIN MOST LIKELY IN THE SE.
THE BULK OF THE PRECIP SHOULD BE OVER BY WED...AS SERLY LL JET AND
PLUME OF ANOMALOUS PWATS LIFTS NORTH OF PA. HOWEVER...UNSETTLED/COOL
WX SEEMS LIKELY THRU THE END OF NEXT WEEK WITH MED RANGE MDL DATA
ALL KEEPING UPPER LOW IN THE VICINITY OF PA. ALTHOUGH AIR MASS
DOESN/T LOOK INITIALLY COLD ENOUGH FOR LAKE EFFECT...A
DEEP...MOIST NWRLY FLOW SHOULD YIELD PERSISTENT UPSLOPE SNOW
SHOWERS ACROSS THE W MTNS WED-FRI. LIGHT ACCUMS SEEM PROBABLE ESP
AT NIGHT. DAYTIME TEMPS WED-THU SHOULD GET ABV FREEZING EVERYWHERE
BASED ON ECMWF ENS MEAN 8H TEMPS.
&&
.AVIATION /16Z SUNDAY THROUGH THURSDAY/...
FRONT HAS CROSSED CENTRAL PENNSYLVANIA...AND SHIFTED WINDS TO THE
NORTHWEST. IT WILL REMAIN BREEZY THIS AFTERNOON...WITH 10 TO 20
KNOT WINDS COMMON.
WITH THE FRONTAL PASSAGE...MOST FOG HAS NOW LIFTED. SOME RESIDUAL
LOWER STRATUS IN THE EAST SHOULD BE GONE IN THE NEXT HOUR OR TWO
AS DRIER LOW LEVEL AIR MOVES IN. AT THE SAME TIME...WNW FLOW WILL
INDUCE TYPICAL MOUNTAIN STRATUS AND SNOW SHOWERS ACROSS THE
WESTERN AND NORTHERN MOUNTAINS. STILL EXPECTING CENTRAL AREAS
/KAOO...KUNV/ TO HAVE CIGS LIFT TO LOW VFR CONDITIONS BY 17Z OR SO.
KJST AND KBFD WILL LIKELY REMAIN IN MVFR CONDITIONS ALL DAY...WITH
KBFD OCCASIONALLY FALLING INTO IFR RANGE AT TIMES IN SNOW SHOWERS.
VFR CONDITIONS FOR MONDAY AS HIGH PRESSURE MOVES ACROSS THE
REGION.
ANOTHER SIGNIFICANT WEATHER SYSTEM WILL BRING LOWERING CONDITIONS
AND MIXED PRECIPITATION TO CENTRAL PENNSYLVANIA BEGINNING
TUESDAY...LASTING INTO WEDNESDAY.
OUTLOOK...
MON...MAINLY VFR.
TUE...DETERIORATING CONDITIONS FROM SW TO NE. MVFR TO IFR.
WED...CONTINUED MIXED PRECIPITATION...MVFR TO IFR.
THU...CONTINUING RAIN AND SNOW SHOWERS...REDUCED CIGS AND VSBYS
ESPECIALLY WEST AND CENTRAL.
&&
.CTP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...FITZGERALD
NEAR TERM...FITZGERALD/MARTIN
SHORT TERM...FITZGERALD
LONG TERM...FITZGERALD
AVIATION...JUNG/RXR
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
931 AM EST SUN FEB 24 2013
.SYNOPSIS...
AN UPPER LEVEL LOW OVER THE GREAT LAKES WILL SLIDE EAST ACROSS
UPSTATE NEW YORK TODAY. A RIDGE OF HIGH PRESSURE WILL BUILD OVER
PENNSYLVANIA ON MONDAY. A STORM SYSTEM OVER THE PLAINS WILL TRACK
NORTHEAST INTO PENNSYLVANIA ON TUESDAY. THE PARENT UPPER LOW WILL
REMAIN OVER THE NORTHEAST CONUS THROUGH THE END OF THE WEEK.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
UPDATED PACKAGE. CURRENT FCST GOOD...SOME SNOW SHOWERS WORKING
IN LATER ACROSS THE NORTH...SOME SUN EARLY THIS MORNING.
EARLIER DISCUSSION BELOW.
DRIER WESTERLY FLOW WORKING INTO CENTRAL PA EARLY THIS AM BEHIND
OCCLUDED FRONT. HOWEVER...ABUNDANT LOW LVL MOISTURE AND A CALM
WIND AHEAD OF THIS BOUNDARY CONTINUES TO RESULT IN AREAS OF FOG
ACROSS THE SUSQ VALLEY AT 11Z. LATEST 3KM HRRR SUGGESTS FOG WILL
LIFT ACROSS THE EASTERN ZONES BY ARND 13Z...AS DRIER AIR ARRIVES.
FOCUS THEN SHIFTS TOWARD UPPER LOW SLIDING EAST FROM THE GRT LKS.
LG SCALE FORCING AHEAD OF THIS FEATURE SHOULD SUPPORT SCT -SHSN
ACROSS THE W MTNS LATER TODAY...WHICH WILL LIKELY DUST THE GROUND
OVER THE HIGHER TERRAIN.
CAA AND PLENTY OF STRATO-CU SHOULD KEEP TEMPS FROM RISING MUCH
TODAY...THE EXCEPTION BEING THE LOWER SUSQ VALLEY...WHERE
DRYING/DOWNSLOPING FLOW SHOULD YIELD PTSUNNY SKIES AND TEMPS
REACHING THE M40S. A TIGHTENING PRES GRADIENT BTWN HIGH PRES OVR
THE MIDWEST AND INTENSIFYING LOW SOUTH OF NEW ENG WILL RESULT IN
AN INCREASINGLY GUSTY WNW WIND ACROSS CENTRAL PA TODAY. BUFKIT MDL
SOUNDINGS INDICATE THERE WILL BE GUSTS ARND 25KTS BY MID AFTN.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH 6 PM MONDAY/...
SCT SNOW SHOWERS ACROSS THE NW MTNS SHOULD TAPER OFF THIS
EVENING...AS UPPER LOW LIFTS OUT AND INVERSION HGTS FALL. EXPECT A
GENERAL CLEARING TREND TONIGHT...AS SFC HIGH BUILDS TOWARD PA FROM
THE MIDWEST. HOWEVER...MDL SOUNDINGS INDICATE LOW LVL MOISTURE
TRAPPED BENEATH INVERSION WILL REMAIN BANKED AGAINST THE NW MTNS
THRU MUCH OF THE NIGHT.
HIGH PRES SHOULD PROVIDE MOST OF THE REGION WITH SUNNY SKIES AND
LGT WINDS MONDAY WITH TEMPS NEAR SEASONAL LEVELS.
&&
.LONG TERM /MONDAY NIGHT THROUGH SATURDAY/...
ALL MED RANGE GUIDANCE INDICATING UPPER LOW OVR THE MISS VALLEY
WILL LIFT NE TOWARD PA ON TUESDAY...PROVIDING INCREASING
CONFIDENCE IN A FAIRLY SIGNIFICANT PRECIP EVENT FOR PA WITH GEFS
MEAN QPF BTWN 0.5 AND 1 INCH. BOTH ECMWF ENSEMBLE MEAN AND GEFS MEAN
SOLUTIONS TRACK A PRIMARY SFC LOW TO OUR WEST WITH A SECONDARY
LIFTING THRU EASTERN PA. THIS SCENARIO WOULD LIKELY RESULT IN SOME
WARMER AIR WORKING IN ALOFT...RESULTING IN MIXED PRECIP TYPES.
ECMWF ENS MEAN 850 TEMPS SUPPORT THE BEST CHC OF WINTRY PRECIP OVR
THE N MTNS WITH RAIN MOST LIKELY IN THE SE.
THE BULK OF THE PRECIP SHOULD BE OVER BY WED...AS SERLY LL JET AND
PLUME OF ANOMALOUS PWATS LIFTS NORTH OF PA. HOWEVER...UNSETTLED/COOL
WX SEEMS LIKELY THRU THE END OF NEXT WEEK WITH MED RANGE MDL DATA
ALL KEEPING UPPER LOW IN THE VICINITY OF PA. ALTHOUGH AIR MASS
DOESN/T LOOK INITIALLY COLD ENOUGH FOR LAKE EFFECT...A
DEEP...MOIST NWRLY FLOW SHOULD YIELD PERSISTENT UPSLOPE SNOW
SHOWERS ACROSS THE W MTNS WED-FRI. LIGHT ACCUMS SEEM PROBABLE ESP
AT NIGHT. DAYTIME TEMPS WED-THU SHOULD GET ABV FREEZING EVERYWHERE
BASED ON ECMWF ENS MEAN 8H TEMPS.
&&
.AVIATION /15Z SUNDAY THROUGH THURSDAY/...
AN UPPER LEVEL LOW OVER THE GREAT LAKES WILL SLIDE EAST ACROSS
UPSTATE NEW YORK TODAY DRAGGING AN OCCLUDED FRONT THROUGH MARKING
THE BEGINNINGS OF DRIER LOW LEVEL AIR...AS WINDS TURN AROUND TO
THE WNW AND BECOME BREEZY. AS THIS HAPPENS THROUGH LATE
MORNING...WIDESPREAD MVFR-IFR CONDITIONS THIS MORNING WILL SWITCH
TO A MORE TYPICAL NW FLOW SCENARIO - WITH MVFR CIGS AND LIGHT SNOW
SHOWERS POSS IN THE WESTERN/NORTHERN HIGHER TERRAIN WHILE CENTRAL
AND SE SECTIONS IMPROVE TO VFR AS DOWNSLOPE FLOW KICKS IN.
ANOTHER SIGNIFICANT WEATHER SYSTEM WILL BRING IMPACTS TO AVIATION
TUE INTO WED.
OUTLOOK...
MON...NO SIG WX EXPECTED.
TUE-THU...STORM SYSTEM BRINGING DETERIORATING CONDITIONS IN
RAIN/SNOW.
&&
.CTP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...FITZGERALD
NEAR TERM...FITZGERALD/MARTIN
SHORT TERM...FITZGERALD
LONG TERM...FITZGERALD
AVIATION...RXR
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
747 AM EST SUN FEB 24 2013
.SYNOPSIS...
AN UPPER LEVEL LOW OVER THE GREAT LAKES WILL SLIDE EAST ACROSS
UPSTATE NEW YORK TODAY. A RIDGE OF HIGH PRESSURE WILL BUILD OVER
PENNSYLVANIA ON MONDAY. A STORM SYSTEM OVER THE PLAINS WILL TRACK
NORTHEAST INTO PENNSYLVANIA ON TUESDAY. THE PARENT UPPER LOW WILL
REMAIN OVER THE NORTHEAST CONUS THROUGH THE END OF THE WEEK.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
DRIER WESTERLY FLOW WORKING INTO CENTRAL PA EARLY THIS AM BEHIND
OCCLUDED FRONT. HOWEVER...ABUNDANT LOW LVL MOISTURE AND A CALM
WIND AHEAD OF THIS BOUNDARY CONTINUES TO RESULT IN AREAS OF FOG
ACROSS THE SUSQ VALLEY AT 11Z. LATEST 3KM HRRR SUGGESTS FOG WILL
LIFT ACROSS THE EASTERN ZONES BY ARND 13Z...AS DRIER AIR ARRIVES.
FOCUS THEN SHIFTS TOWARD UPPER LOW SLIDING EAST FROM THE GRT LKS.
LG SCALE FORCING AHEAD OF THIS FEATURE SHOULD SUPPORT SCT -SHSN
ACROSS THE W MTNS LATER TODAY...WHICH WILL LIKELY DUST THE GROUND
OVER THE HIGHER TERRAIN.
CAA AND PLENTY OF STRATO-CU SHOULD KEEP TEMPS FROM RISING MUCH
TODAY...THE EXCEPTION BEING THE LOWER SUSQ VALLEY...WHERE
DRYING/DOWNSLOPING FLOW SHOULD YIELD PTSUNNY SKIES AND TEMPS
REACHING THE M40S. A TIGHTENING PRES GRADIENT BTWN HIGH PRES OVR
THE MIDWEST AND INTENSIFYING LOW SOUTH OF NEW ENG WILL RESULT IN
AN INCREASINGLY GUSTY WNW WIND ACROSS CENTRAL PA TODAY. BUFKIT MDL
SOUNDINGS INDICATE THERE WILL BE GUSTS ARND 25KTS BY MID AFTN.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH 6 PM MONDAY/...
SCT SNOW SHOWERS ACROSS THE NW MTNS SHOULD TAPER OFF THIS
EVENING...AS UPPER LOW LIFTS OUT AND INVERSION HGTS FALL. EXPECT A
GENERAL CLEARING TREND TONIGHT...AS SFC HIGH BUILDS TOWARD PA FROM
THE MIDWEST. HOWEVER...MDL SOUNDINGS INDICATE LOW LVL MOISTURE
TRAPPED BENEATH INVERSION WILL REMAIN BANKED AGAINST THE NW MTNS
THRU MUCH OF THE NIGHT.
HIGH PRES SHOULD PROVIDE MOST OF THE REGION WITH SUNNY SKIES AND
LGT WINDS MONDAY WITH TEMPS NEAR SEASONAL LEVELS.
&&
.LONG TERM /MONDAY NIGHT THROUGH SATURDAY/...
ALL MED RANGE GUIDANCE INDICATING UPPER LOW OVR THE MISS VALLEY
WILL LIFT NE TOWARD PA ON TUESDAY...PROVIDING INCREASING
CONFIDENCE IN A FAIRLY SIGNIFICANT PRECIP EVENT FOR PA WITH GEFS
MEAN QPF BTWN 0.5 AND 1 INCH. BOTH ECMWF ENSEMBLE MEAN AND GEFS MEAN
SOLUTIONS TRACK A PRIMARY SFC LOW TO OUR WEST WITH A SECONDARY
LIFTING THRU EASTERN PA. THIS SCENARIO WOULD LIKELY RESULT IN SOME
WARMER AIR WORKING IN ALOFT...RESULTING IN MIXED PRECIP TYPES.
ECMWF ENS MEAN 850 TEMPS SUPPORT THE BEST CHC OF WINTRY PRECIP OVR
THE N MTNS WITH RAIN MOST LIKELY IN THE SE.
THE BULK OF THE PRECIP SHOULD BE OVER BY WED...AS SERLY LL JET AND
PLUME OF ANOMALOUS PWATS LIFTS NORTH OF PA. HOWEVER...UNSETTLED/COOL
WX SEEMS LIKELY THRU THE END OF NEXT WEEK WITH MED RANGE MDL DATA
ALL KEEPING UPPER LOW IN THE VICINITY OF PA. ALTHOUGH AIR MASS
DOESN/T LOOK INITIALLY COLD ENOUGH FOR LAKE EFFECT...A
DEEP...MOIST NWRLY FLOW SHOULD YIELD PERSISTENT UPSLOPE SNOW
SHOWERS ACROSS THE W MTNS WED-FRI. LIGHT ACCUMS SEEM PROBABLE ESP
AT NIGHT. DAYTIME TEMPS WED-THU SHOULD GET ABV FREEZING EVERYWHERE
BASED ON ECMWF ENS MEAN 8H TEMPS.
&&
.AVIATION /12Z SUNDAY THROUGH THURSDAY/...
AN UPPER LEVEL LOW OVER THE GREAT LAKES WILL SLIDE EAST ACROSS
UPSTATE NEW YORK TODAY DRAGGING AN OCCLUDED FRONT THROUGH MARKING
THE BEGINNINGS OF DRIER LOW LEVEL AIR...AS WINDS TURN AROUND TO
THE WNW AND BECOME BREEZY. AS THIS HAPPENS THROUGH LATE
MORNING...WIDESPREAD MVFR-IFR CONDITIONS THIS MORNING WILL SWITCH
TO A MORE TYPICAL NW FLOW SCENARIO - WITH MVFR CIGS AND LIGHT SNOW
SHOWERS POSS IN THE WESTERN/NORTHERN HIGHER TERRAIN WHILE CENTRAL
AND SE SECTIONS IMPROVE TO VFR AS DOWNSLOPE FLOW KICKS IN.
ANOTHER SIGNIFICANT WEATHER SYSTEM WILL BRING IMPACTS TO AVIATION
TUE INTO WED.
OUTLOOK...
MON...NO SIG WX EXPECTED.
TUE-THU...STORM SYSTEM BRINGING DETERIORATING CONDITIONS IN
RAIN/SNOW.
&&
.CTP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...FITZGERALD
NEAR TERM...FITZGERALD
SHORT TERM...FITZGERALD
LONG TERM...FITZGERALD
AVIATION...RXR
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
634 AM EST SUN FEB 24 2013
.SYNOPSIS...
AN UPPER LEVEL LOW OVER THE GREAT LAKES WILL SLIDE EAST ACROSS
UPSTATE NEW YORK TODAY. A RIDGE OF HIGH PRESSURE WILL BUILD OVER
PENNSYLVANIA ON MONDAY. A STORM SYSTEM OVER THE PLAINS WILL TRACK
NORTHEAST INTO PENNSYLVANIA ON TUESDAY. THE PARENT UPPER LOW WILL
REMAIN OVER THE NORTHEAST CONUS THROUGH THE END OF THE WEEK.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
DRIER WESTERLY FLOW WORKING INTO CENTRAL PA EARLY THIS AM BEHIND OCCLUDED
FRONT. HOWEVER...ABUNDANT LOW LVL MOISTURE AND A CALM WIND AHEAD
OF THIS BOUNDARY CONTINUES TO RESULT IN AREAS OF FOG ACROSS THE
SUSQ VALLEY AT 11Z. LATEST 3KM HRRR SUGGESTS FOG WILL LIFT ACROSS
THE EASTERN ZONES BY ARND 13Z...AS DRIER AIR ARRIVES. FOCUS THEN
SHIFTS TOWARD UPPER LOW SLIDING EAST FROM THE GRT LKS. LG SCALE
FORCING AHEAD OF THIS FEATURE SHOULD SUPPORT SCT -SHSN ACROSS THE
W MTNS LATER TODAY...WHICH WILL LIKELY DUST THE GROUND OVER THE
HIGHER TERRAIN.
CAA AND PLENTY OF STRATO-CU SHOULD KEEP TEMPS FROM RISING MUCH
TODAY...THE EXCEPTION BEING THE LOWER SUSQ VALLEY...WHERE
DRYING/DOWNSLOPING FLOW SHOULD YIELD PTSUNNY SKIES AND TEMPS
REACHING THE M40S. A TIGHTENING PRES GRADIENT BTWN HIGH PRES OVR
THE MIDWEST AND INTENSIFYING LOW SOUTH OF NEW ENG WILL RESULT IN
AN INCREASINGLY GUSTY WNW WIND ACROSS CENTRAL PA TODAY. BUFKIT MDL
SOUNDINGS INDICATE THERE WILL BE GUSTS ARND 25KTS BY MID AFTN.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH 6 PM MONDAY/...
SCT SNOW SHOWERS ACROSS THE NW MTNS SHOULD TAPER OFF THIS
EVENING...AS UPPER LOW LIFTS OUT AND INVERSION HGTS FALL. EXPECT A
GENERAL CLEARING TREND TONIGHT...AS SFC HIGH BUILDS TOWARD PA FROM
THE MIDWEST. HOWEVER...MDL SOUNDINGS INDICATE LOW LVL MOISTURE
TRAPPED BENEATH INVERSION WILL REMAIN BANKED AGAINST THE NW MTNS
THRU MUCH OF THE NIGHT.
HIGH PRES SHOULD PROVIDE MOST OF THE REGION WITH SUNNY SKIES AND
LGT WINDS MONDAY WITH TEMPS NEAR SEASONAL LEVELS.
&&
.LONG TERM /MONDAY NIGHT THROUGH SATURDAY/...
ALL MED RANGE GUIDANCE INDICATING UPPER LOW OVR THE MISS VALLEY
WILL LIFT NE TOWARD PA ON TUESDAY...PROVIDING INCREASING
CONFIDENCE IN A FAIRLY SIGNIFICANT PRECIP EVENT FOR PA WITH GEFS
MEAN QPF BTWN 0.5 AND 1 INCH. BOTH ECMWF ENSEMBLE MEAN AND GEFS MEAN
SOLUTIONS TRACK A PRIMARY SFC LOW TO OUR WEST WITH A SECONDARY
LIFTING THRU EASTERN PA. THIS SCENARIO WOULD LIKELY RESULT IN SOME
WARMER AIR WORKING IN ALOFT...RESULTING IN MIXED PRECIP TYPES.
ECMWF ENS MEAN 850 TEMPS SUPPORT THE BEST CHC OF WINTRY PRECIP OVR
THE N MTNS WITH RAIN MOST LIKELY IN THE SE.
THE BULK OF THE PRECIP SHOULD BE OVER BY WED...AS SERLY LL JET AND
PLUME OF ANOMALOUS PWATS LIFTS NORTH OF PA. HOWEVER...UNSETTLED/COOL
WX SEEMS LIKELY THRU THE END OF NEXT WEEK WITH MED RANGE MDL DATA
ALL KEEPING UPPER LOW IN THE VICINITY OF PA. ALTHOUGH AIR MASS
DOESN/T LOOK INITIALLY COLD ENOUGH FOR LAKE EFFECT...A
DEEP...MOIST NWRLY FLOW SHOULD YIELD PERSISTENT UPSLOPE SNOW
SHOWERS ACROSS THE W MTNS WED-FRI. LIGHT ACCUMS SEEM PROBABLE ESP
AT NIGHT. DAYTIME TEMPS WED-THU SHOULD GET ABV FREEZING EVERYWHERE
BASED ON ECMWF ENS MEAN 8H TEMPS.
&&
.AVIATION /12Z SUNDAY THROUGH THURSDAY/...
LIGHT WIND AND NARROW T/TD SPREAD OF JUST A FEW DEG F COMBINED
WITH THE TEMPORARY CLEARING EARLIER THIS EVENING BRINGING SEVERAL
DEG F OF RADIATIONAL COOLING QUICKLY REDEVELOPED THE LOW
STRATUS/STRATOCU DECK ACROSS THE WRN MTNS.
THE CIGS FOR THE REST OF THE OVERNIGHT HOURS /RANGING FROM
GENERALLY MVFR ACROSS THE WEST...TO IFR AND LIFR IN THE EAST WILL
HOLD...OR DROP BY UP TO SEVERAL HUNDRED FEET AS THERE IS LITTLE
DRY/COLD ADVECTION TO SPEAK OF.
VSBYS WILL LIKELY STAY WITHIN THE MVFR RANGE WEST...AND VARY
BETWEEN VLIFR AND IFR IN FOG ACROSS THE SUSQ VALLEY AND PORTIONS
OF CENTRAL MTNS. THE LOWEST CIGS WILL PERSIST ACROSS THE SUSQ VALLEY
/TAF SITES KIPT...KMDT AND KLNS/ UNTIL 10-12Z SUNDAY...BEFORE
GRADUALLY IMPROVING TO MVFR AND BORDERLINE VFR FOR THE LATE
MORNING AND AFTERNOON HOURS SUNDAY.
SOME SNOW SHOWERS AND CONTINUED MVFR FLYING CONDITIONS WILL BE
POSSIBLE AT BFD...AND PERHAPS JST...AS THE UPPER LVL LOW AND COLD
AIR ALOFT WILL BE SLOW TO MOVE OUT.
ANOTHER SIGNIFICANT WEATHER SYSTEM EXPECTED ON TUE.
OUTLOOK...
MON...NO SIG WX EXPECTED.
TUE-THU...STORM SYSTEM BRINGING DETERIORATING CONDITIONS IN
RAIN/SNOW.
&&
.CTP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...FITZGERALD
NEAR TERM...FITZGERALD
SHORT TERM...FITZGERALD
LONG TERM...FITZGERALD
AVIATION...LAMBERT/RXR
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
550 AM EST SUN FEB 24 2013
.SYNOPSIS...
AN UPPER LEVEL LOW OVER THE GREAT LAKES WILL SLIDE EAST ACROSS
UPSTATE NEW YORK TODAY. A RIDGE OF HIGH PRESSURE WILL BUILD OVER
PENNSYLVANIA ON MONDAY. A STORM SYSTEM OVER THE PLAINS WILL TRACK
NORTHEAST INTO PENNSYLVANIA ON TUESDAY. THE PARENT UPPER LOW WILL
REMAIN OVER THE NORTHEAST CONUS THROUGH THE END OF THE WEEK.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
DRIER WESTERLY FLOW WORKING INTO CENTRAL PA EARLY THIS AM BEHIND OCCLUDED
FRONT. HOWEVER...ABUNDANT LOW LVL MOISTURE AND A CALM WIND AHEAD
OF THIS BOUNDARY CONTINUES TO RESULT IN AREAS OF FOG ACROSS THE
SUSQ VALLEY AT 10Z. LATEST 3KM HRRR SUGGESTS FOG WILL LIFT ACROSS
THE EASTERN ZONES BY ARND 13Z...AS DRIER AIR ARRIVES. FOCUS THEN
SHIFTS TOWARD UPPER LOW SLIDING EAST FROM THE GRT LKS. LG SCALE
FORCING AHEAD OF THIS FEATURE SHOULD SUPPORT SCT -SHSN ACROSS THE
W MTNS LATER TODAY...WHICH WILL LIKELY DUST THE GROUND OVER THE
HIGHER TERRAIN.
CAA AND PLENTY OF STRATO-CU SHOULD KEEP TEMPS FROM RISING MUCH
TODAY...THE EXCEPTION BEING THE LOWER SUSQ VALLEY...WHERE
DRYING/DOWNSLOPING FLOW SHOULD YIELD PTSUNNY SKIES AND TEMPS
REACHING THE M40S. A TIGHTENING PRES GRADIENT BTWN HIGH PRES OVR
THE MIDWEST AND INTENSIFYING LOW SOUTH OF NEW ENG WILL RESULT IN
AN INCREASINGLY GUSTY WNW WIND ACROSS CENTRAL PA TODAY. BUFKIT MDL
SOUNDINGS INDICATE THERE WILL BE GUSTS ARND 25KTS BY MID AFTN.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH 6 PM MONDAY/...
SCT SNOW SHOWERS ACROSS THE NW MTNS SHOULD TAPER OFF THIS
EVENING...AS UPPER LOW LIFTS OUT AND INVERSION HGTS FALL. EXPECT A
GENERAL CLEARING TREND TONIGHT...AS SFC HIGH BUILDS TOWARD PA FROM
THE MIDWEST. HOWEVER...MDL SOUNDINGS INDICATE LOW LVL MOISTURE
TRAPPED BENEATH INVERSION WILL REMAIN BANKED AGAINST THE NW MTNS
THRU MUCH OF THE NIGHT.
HIGH PRES SHOULD PROVIDE MOST OF THE REGION WITH SUNNY SKIES AND
LGT WINDS MONDAY WITH TEMPS NEAR SEASONAL LEVELS.
&&
.LONG TERM /MONDAY NIGHT THROUGH SATURDAY/...
ALL MED RANGE GUIDANCE INDICATING UPPER LOW OVR THE MISS VALLEY
WILL LIFT NE TOWARD PA ON TUESDAY...PROVIDING INCREASING
CONFIDENCE IN A FAIRLY SIGNIFICANT PRECIP EVENT FOR PA WITH GEFS
MEAN QPF BTWN 0.5 AND 1 INCH. BOTH ECMWF ENSEMBLE MEAN AND GEFS MEAN
SOLUTIONS TRACK A PRIMARY SFC LOW TO OUR WEST WITH A SECONDARY
LIFTING THRU EASTERN PA. THIS SCENARIO WOULD LIKELY RESULT IN SOME
WARMER AIR WORKING IN ALOFT...RESULTING IN MIXED PRECIP TYPES.
ECMWF ENS MEAN 850 TEMPS SUPPORT THE BEST CHC OF WINTRY PRECIP OVR
THE N MTNS WITH RAIN MOST LIKELY IN THE SE.
THE BULK OF THE PRECIP SHOULD BE OVER BY WED...AS SERLY LL JET AND
PLUME OF ANOMALOUS PWATS LIFTS NORTH OF PA. HOWEVER...UNSETTLED/COOL
WX SEEMS LIKELY THRU THE END OF NEXT WEEK WITH MED RANGE MDL DATA
ALL KEEPING UPPER LOW IN THE VICINITY OF PA. ALTHOUGH AIR MASS
DOESN/T LOOK INITIALLY COLD ENOUGH FOR LAKE EFFECT...A
DEEP...MOIST NWRLY FLOW SHOULD YIELD PERSISTENT UPSLOPE SNOW
SHOWERS ACROSS THE W MTNS WED-FRI. LIGHT ACCUMS SEEM PROBABLE ESP
AT NIGHT. DAYTIME TEMPS WED-THU SHOULD GET ABV FREEZING EVERYWHERE
BASED ON ECMWF ENS MEAN 8H TEMPS.
&&
.AVIATION /10Z SUNDAY THROUGH THURSDAY/...
LIGHT WIND AND NARROW T/TD SPREAD OF JUST A FEW DEG F COMBINED
WITH THE TEMPORARY CLEARING EARLIER THIS EVENING BRINGING SEVERAL
DEG F OF RADIATIONAL COOLING QUICKLY REDEVELOPED THE LOW
STRATUS/STRATOCU DECK ACROSS THE WRN MTNS.
THE CIGS FOR THE REST OF THE OVERNIGHT HOURS /RANGING FROM
GENERALLY MVFR ACROSS THE WEST...TO IFR AND LIFR IN THE EAST WILL
HOLD...OR DROP BY UP TO SEVERAL HUNDRED FEET AS THERE IS LITTLE
DRY/COLD ADVECTION TO SPEAK OF.
VSBYS WILL LIKELY STAY WITHIN THE MVFR RANGE WEST...AND VARY
BETWEEN VLIFR AND IFR IN FOG ACROSS THE SUSQ VALLEY AND PORTIONS
OF CENTRAL MTNS. THE LOWEST CIGS WILL PERSIST ACROSS THE SUSQ VALLEY
/TAF SITES KIPT...KMDT AND KLNS/ UNTIL 10-12Z SUNDAY...BEFORE
GRADUALLY IMPROVING TO MVFR AND BORDERLINE VFR FOR THE LATE
MORNING AND AFTERNOON HOURS SUNDAY.
SOME SNOW SHOWERS AND CONTINUED MVFR FLYING CONDITIONS WILL BE
POSSIBLE AT BFD...AND PERHAPS JST...AS THE UPPER LVL LOW AND COLD
AIR ALOFT WILL BE SLOW TO MOVE OUT.
ANOTHER SIGNIFICANT WEATHER SYSTEM EXPECTED ON TUE.
OUTLOOK...
MON...NO SIG WX EXPECTED.
TUE-THU...STORM SYSTEM BRINGING DETERIORATING CONDITIONS IN
RAIN/SNOW.
&&
.CTP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...FITZGERALD
NEAR TERM...FITZGERALD
SHORT TERM...FITZGERALD
LONG TERM...FITZGERALD
AVIATION...LAMBERT/RXR
AREA FORECAST DISCUSSION...UPDATED
NWS FORT WORTH TX
802 PM CST MON FEB 25 2013
.UPDATE...
PREVIOUS FRONTOGENETICAL SNOW BAND THAT MOVED THROUGH MONTAGUE
COUNTY AN HOUR OR SO AGO HAS WEAKENED CONSIDERABLY...AS RETURNS
VIA CLEAR AIR MODE ON RADAR AND DUAL POL PRODUCTS INDICATE. HIGH-
RES RAP AND WRF MODELS ALSO INDICATE THIS TREND...AS ISENTROPIC
DOWNGLIDE AND SUBSIDENCE CONTINUE TO WEAKEN RETURNS ACROSS NORTH
TEXAS IN WAKE OF THE MID LEVEL LOW MOVING INTO SOUTHEAST OKLAHOMA
THIS EVENING. MODEL SOUNDINGS DO INDICATE THE TOP-DOWN DRYING OF
THE COLUMN BY MID EVENING INDICATIVE OF SUBSIDENCE WITH DENDRITE
SEEDING FROM THE MID AND UPPER LEVELS NO LONGER AVAILABLE.
WE DID LEAVE LOW CHANCES OF A VERY LIGHT RAIN/SNOW MIX OR A MENTION
OF SPRINKLES OR FLURRIES WITH ONLY SHALLOW MOISTURE BEING LEFT
OVER THROUGH THE OVERNIGHT. WE ARE CANCELING THE WINTER WEATHER
ADVISORY FOR OUR NORTHWEST COUNTIES...BUT MAINTAINING THE WIND
ADVISORY OVERNIGHT WITH STRONG COLD ADVECTION AND A TIGHT WNW
PRESSURE GRADIENT MAINTAINING THROUGH THE NIGHT. THE PERSISTENT
LINGERING WRAP-AROUND STRATUS WILL KEEP MOST AREAS FROM REACHING
FREEZING BY TUESDAY MORNING. WNW WINDS 25-35 WITH GUSTS TO 40-45
WILL CONTINUE INTO THE EARLY MORNING HOURS TUESDAY.
05/
&&
.AVIATION...
MAIN CONCERN OVER THE NEXT SEVERAL HOURS WILL BE THE GUSTY
WESTERLY WINDS AND THE IMPACTS TO THE NORTH-SOUTH CONFIGURED
RUNWAYS. SURFACE TROUGH THAT HAS BEEN ANCHORED NEAR KSPS FOR MOST
OF THE DAY IS SHIFTING EAST...AS EVIDENT BY THE VEERING WINDS AT
THE SITE...AND WE SHOULD SEE SLIGHT VEERING OF THE WINDS SHORTLY.
WILL FOLLOW THE LATEST RAP WHICH BEGINS THE WIND AT 270 AT 00Z
AND VEERS THE DIRECTION TO 290 BY 2Z. THIS SHOULD HELP ALLEVIATE
SOME CONCERNS AT THE LARGER AIRPORTS. WIND SPEEDS WILL REMAIN HIGH
THROUGH THE NIGHT WITH GUSTS LIKELY EXCEEDING 35 KNOTS.
MVFR CIGS REMAIN JUST TO THE WEST OF THE METROPLEX AIRPORTS AND
THESE ARE EXPECTED TO ADVECT INTO THE THE TERMINALS LIKELY BETWEEN
01Z AND 02Z. CLOUD BASES WILL LIKELY BE BELOW 2KFT WHICH WILL ONLY
CAUSE MORE CONCERNS. THESE CLOUDS SHOULD SCATTER OUT AROUND
DAYBREAK AS DRIER AIR FILTERS INTO THE REGION.
A RAIN/SNOW MIX IS POSSIBLE AT THE METROPLEX AIRPORTS...BUT
PROBABILITIES ARE TOO LOW TO MENTION AT THIS TIME. IF SNOW DOES
OCCUR...TEMPERATURES WOULD BE WELL ABOVE FREEZING AND LITTLE TO NO
IMPACTS WOULD OCCUR. THE BEST TIMING FOR POTENTIAL PRECIP WOULD BE
BETWEEN 7 AND 9 PM.
WIND SPEEDS WILL REMAIN GUSTY TOMORROW...BUT SHOULD BE LESS THAN
TODAY. WIND DIRECTION TOMORROW IS EXPECTED TO BE AROUND 300-320.
HAMPSHIRE
&&
.PREV DISCUSSION... /ISSUED 350 PM CST MON FEB 25 2013/
POWERFUL WINTER STORM CONTINUES TO MOVE THROUGH THE SOUTHERN
PLAINS THIS AFTERNOON RESULTING IN PRIMARILY A WIND EVENT ACROSS
NORTH TEXAS...BUT SOME WINTRY WEATHER IS EXPECTED THROUGH THIS
EVENING FOR PARTS OF THE AREA. LATEST SURFACE ANALYSIS SHOWS THE
CENTER OF THE SURFACE LOW NEAR EL DORADO ARKANSAS WHERE 3 HOUR
PRESSURE FALLS ARE IN EXCESS OF 7MB. PRESSURE FALLS EXTEND ALL THE
WAY WESTWARD TOWARD WICHITA FALLS WHERE A SURFACE TROUGH HAS
PERSISTED ALL DAY. THESE PERSISTENT PRESSURE FALLS ARE AN
INDICATION THAT THE ENTIRE UPPER STORM SYSTEM IS DEEPENING. WATER
VAPOR IMAGERY SHOWS A WELL DEFINED CIRCULATION WHICH APPEARS TO
NOW BE MOVING DUE EAST TOWARD THE BEST SURFACE PRESSURE FALLS.
THIS IS CONCERNING BECAUSE SUBSTANTIAL WRAP AROUND PRECIPITATION
DRIVEN BY FRONTOGENETICAL FORCING WILL LIKELY TRACK FARTHER SOUTH
THAN EARLIER ANTICIPATED. SHORT TERM HIGH RESOLUTION GUIDANCE
APPEARS TO HAVE SOMEWHAT OF A HANDLE ON THE MOVEMENT OF THE UPPER
SYSTEM BUT PRECIPITATION IS QUICKLY ERODED DUE TO STRONG
SUBSIDENCE. MESOSCALE FRONTOGENETICAL FORCING IS LIKELY TO WIN OUT
AT LEAST FOR A FEW HOURS ON THE BACK SIDE OF THE SYSTEM RESULTING
IN PRECIPITATION ACROSS MAINLY THE NORTHWEST COUNTIES THROUGH MIDNIGHT.
CONCERNING THE PRECIPITATION...FORECAST SOUNDINGS FROM BOTH THE
HIGH RES 3KM TTU WRF AND RAP MODEL SUGGEST THAT THE THERMAL
PROFILE WILL BE SUFFICIENTLY COLD FOR SNOWFALL PRODUCTION
GENERALLY NORTH OF INTERSTATE 20 THROUGH LATE TONIGHT...DESPITE
THE WARM SURFACE TEMPERATURES. INITIAL CONVECTIVE SHOWERS
NORTHEAST OF THE METROPLEX SHOULD REMAIN ALL LIQUID. GIVEN THE
POTENTIAL FOR SNOWFALL...ALONG WITH STRONG GUSTY WINDS...HAVE
ISSUED A SHORT DURATION WINTER WEATHER ADVISORY FOR THE FAR
NORTHWEST COUNTIES THROUGH MIDNIGHT. WITH WARM GROUND TEMPERATURES
AND GENERALLY ABOVE FREEZING SURFACE TEMPERATURES...EXPECT ANY
ACCUMULATIONS TO BE CONFINED TO GRASSY SURFACES. THE PRIMARY
CONCERN WILL BE FOR BLOWING SNOW WHICH COULD REDUCE VISIBILITY TO
LESS THAN 1/2 MILE AT TIMES. ROADS SHOULD REMAIN IN GOOD SHAPE.
THE OTHER MAIN CONCERN IS WINDS THROUGH LATE TONIGHT. WITH THE
CENTER OF THE SURFACE LOW NEARBY FOR MUCH OF THE AFTERNOON...WINDS
HAVE GENERALLY BEEN HIGHEST ACROSS THE SOUTHERN COUNTIES WHERE
GUSTS TO 54 MPH HAVE BEEN REPORTED. WITH THE SURFACE LOW NOW
MOVING EAST...THE PRESSURE GRADIENT WILL CONTINUE TO TIGHTEN
THROUGH EVENING. THE STRONGEST LOW LEVEL JET WILL BE CENTERED
ACROSS THE AREA RIGHT AROUND MIDNIGHT SO IT APPEARS THAT THE
STRONGEST WINDS ACROSS MUCH OF THE REGION ARE STILL TO COME.
ONE LIMITING FACTOR TO STRONGER WINDS WILL BE THE FACT THAT IT
WILL BE NIGHT WHEN THE STRONGEST WINDS ALOFT ARE OVERHEAD. THE CURRENT
WIND ADVISORY WILL REMAIN IN EFFECT THROUGH 4 AM FOR ALL OF NORTH
TEXAS.
WITH THE ENTIRE SYSTEM MOVING TO THE NORTHEAST TOMORROW...SKIES
SHOULD CLEAR AND WINDS WILL DIMINISH. A COUPLE OF REINFORCING
FRONTS...ONE ON WEDNESDAY AND ANOTHER LATE THURSDAY NIGHT...WILL
KEEP TEMPERATURES COOL THROUGH THE WEEK. NO SIGNIFICANT CHANGES TO
THE EXTENDED FORECAST AS IT APPEARS THAT IT WILL REMAIN DRY
THROUGH THE PERIOD.
DUNN
&&
.PRELIMINARY POINT TEMPS/POPS...
DALLAS-FT. WORTH, TX 36 54 34 54 34 / 20 5 0 0 5
WACO, TX 37 61 34 60 33 / 5 0 0 0 5
PARIS, TX 36 49 31 51 31 / 30 5 0 0 5
DENTON, TX 36 53 30 51 31 / 30 5 0 0 5
MCKINNEY, TX 36 52 32 51 32 / 20 5 0 0 5
DALLAS, TX 37 56 35 55 35 / 20 5 0 0 5
TERRELL, TX 37 52 34 54 34 / 10 5 0 0 5
CORSICANA, TX 38 57 35 58 34 / 5 0 0 0 5
TEMPLE, TX 37 63 36 63 33 / 5 0 0 0 5
MINERAL WELLS, TX 34 57 30 54 29 / 30 0 0 0 5
&&
.FWD WATCHES/WARNINGS/ADVISORIES...
WIND ADVISORY UNTIL 4 AM CST TUESDAY FOR TXZ091>095-100>107-
115>123-129>135-141>148-156>162-174-175.
&&
$$
85/05
AREA FORECAST DISCUSSION...UPDATED
NWS FORT WORTH TX
509 PM CST MON FEB 25 2013
.AVIATION...
MAIN CONCERN OVER THE NEXT SEVERAL HOURS WILL BE THE GUSTY
WESTERLY WINDS AND THE IMPACTS TO THE NORTH-SOUTH CONFIGURED
RUNWAYS. SURFACE TROUGH THAT HAS BEEN ANCHORED NEAR KSPS FOR MOST
OF THE DAY IS SHIFTING EAST...AS EVIDENT BY THE VEERING WINDS AT
THE SITE...AND WE SHOULD SEE SLIGHT VEERING OF THE WINDS SHORTLY.
WILL FOLLOW THE LATEST RAP WHICH BEGINS THE WIND AT 270 AT 00Z
AND VEERS THE DIRECTION TO 290 BY 2Z. THIS SHOULD HELP ALLEVIATE
SOME CONCERNS AT THE LARGER AIRPORTS. WIND SPEEDS WILL REMAIN HIGH
THROUGH THE NIGHT WITH GUSTS LIKELY EXCEEDING 35 KNOTS.
MVFR CIGS REMAIN JUST TO THE WEST OF THE METROPLEX AIRPORTS AND
THESE ARE EXPECTED TO ADVECT INTO THE THE TERMINALS LIKELY BETWEEN
01Z AND 02Z. CLOUD BASES WILL LIKELY BE BELOW 2KFT WHICH WILL ONLY
CAUSE MORE CONCERNS. THESE CLOUDS SHOULD SCATTER OUT AROUND
DAYBREAK AS DRIER AIR FILTERS INTO THE REGION.
A RAIN/SNOW MIX IS POSSIBLE AT THE METROPLEX AIRPORTS...BUT
PROBABILITIES ARE TOO LOW TO MENTION AT THIS TIME. IF SNOW DOES
OCCUR...TEMPERATURES WOULD BE WELL ABOVE FREEZING AND LITTLE TO NO
IMPACTS WOULD OCCUR. THE BEST TIMING FOR POTENTIAL PRECIP WOULD BE
BETWEEN 7 AND 9 PM.
WIND SPEEDS WILL REMAIN GUSTY TOMORROW...BUT SHOULD BE LESS THAN
TODAY. WIND DIRECTION TOMORROW IS EXPECTED TO BE AROUND 300-320.
HAMPSHIRE
&&
.PREV DISCUSSION... /ISSUED 350 PM CST MON FEB 25 2013/
POWERFUL WINTER STORM CONTINUES TO MOVE THROUGH THE SOUTHERN
PLAINS THIS AFTERNOON RESULTING IN PRIMARILY A WIND EVENT ACROSS
NORTH TEXAS...BUT SOME WINTRY WEATHER IS EXPECTED THROUGH THIS
EVENING FOR PARTS OF THE AREA. LATEST SURFACE ANALYSIS SHOWS THE
CENTER OF THE SURFACE LOW NEAR EL DORADO ARKANSAS WHERE 3 HOUR
PRESSURE FALLS ARE IN EXCESS OF 7MB. PRESSURE FALLS EXTEND ALL THE
WAY WESTWARD TOWARD WICHITA FALLS WHERE A SURFACE TROUGH HAS
PERSISTED ALL DAY. THESE PERSISTENT PRESSURE FALLS ARE AN
INDICATION THAT THE ENTIRE UPPER STORM SYSTEM IS DEEPENING. WATER
VAPOR IMAGERY SHOWS A WELL DEFINED CIRCULATION WHICH APPEARS TO
NOW BE MOVING DUE EAST TOWARD THE BEST SURFACE PRESSURE FALLS.
THIS IS CONCERNING BECAUSE SUBSTANTIAL WRAP AROUND PRECIPITATION
DRIVEN BY FRONTOGENETICAL FORCING WILL LIKELY TRACK FARTHER SOUTH
THAN EARLIER ANTICIPATED. SHORT TERM HIGH RESOLUTION GUIDANCE
APPEARS TO HAVE SOMEWHAT OF A HANDLE ON THE MOVEMENT OF THE UPPER
SYSTEM BUT PRECIPITATION IS QUICKLY ERODED DUE TO STRONG
SUBSIDENCE. MESOSCALE FRONTOGENETICAL FORCING IS LIKELY TO WIN OUT
AT LEAST FOR A FEW HOURS ON THE BACK SIDE OF THE SYSTEM RESULTING
IN PRECIPITATION ACROSS MAINLY THE NORTHWEST COUNTIES THROUGH MIDNIGHT.
CONCERNING THE PRECIPITATION...FORECAST SOUNDINGS FROM BOTH THE
HIGH RES 3KM TTU WRF AND RAP MODEL SUGGEST THAT THE THERMAL
PROFILE WILL BE SUFFICIENTLY COLD FOR SNOWFALL PRODUCTION
GENERALLY NORTH OF INTERSTATE 20 THROUGH LATE TONIGHT...DESPITE
THE WARM SURFACE TEMPERATURES. INITIAL CONVECTIVE SHOWERS
NORTHEAST OF THE METROPLEX SHOULD REMAIN ALL LIQUID. GIVEN THE
POTENTIAL FOR SNOWFALL...ALONG WITH STRONG GUSTY WINDS...HAVE
ISSUED A SHORT DURATION WINTER WEATHER ADVISORY FOR THE FAR
NORTHWEST COUNTIES THROUGH MIDNIGHT. WITH WARM GROUND TEMPERATURES
AND GENERALLY ABOVE FREEZING SURFACE TEMPERATURES...EXPECT ANY
ACCUMULATIONS TO BE CONFINED TO GRASSY SURFACES. THE PRIMARY
CONCERN WILL BE FOR BLOWING SNOW WHICH COULD REDUCE VISIBILITY TO
LESS THAN 1/2 MILE AT TIMES. ROADS SHOULD REMAIN IN GOOD SHAPE.
THE OTHER MAIN CONCERN IS WINDS THROUGH LATE TONIGHT. WITH THE
CENTER OF THE SURFACE LOW NEARBY FOR MUCH OF THE AFTERNOON...WINDS
HAVE GENERALLY BEEN HIGHEST ACROSS THE SOUTHERN COUNTIES WHERE
GUSTS TO 54 MPH HAVE BEEN REPORTED. WITH THE SURFACE LOW NOW
MOVING EAST...THE PRESSURE GRADIENT WILL CONTINUE TO TIGHTEN
THROUGH EVENING. THE STRONGEST LOW LEVEL JET WILL BE CENTERED
ACROSS THE AREA RIGHT AROUND MIDNIGHT SO IT APPEARS THAT THE
STRONGEST WINDS ACROSS MUCH OF THE REGION ARE STILL TO COME.
ONE LIMITING FACTOR TO STRONGER WINDS WILL BE THE FACT THAT IT
WILL BE NIGHT WHEN THE STRONGEST WINDS ALOFT ARE OVERHEAD. THE CURRENT
WIND ADVISORY WILL REMAIN IN EFFECT THROUGH 4 AM FOR ALL OF NORTH
TEXAS.
WITH THE ENTIRE SYSTEM MOVING TO THE NORTHEAST TOMORROW...SKIES
SHOULD CLEAR AND WINDS WILL DIMINISH. A COUPLE OF REINFORCING
FRONTS...ONE ON WEDNESDAY AND ANOTHER LATE THURSDAY NIGHT...WILL
KEEP TEMPERATURES COOL THROUGH THE WEEK. NO SIGNIFICANT CHANGES TO
THE EXTENDED FORECAST AS IT APPEARS THAT IT WILL REMAIN DRY
THROUGH THE PERIOD.
DUNN
&&
.PRELIMINARY POINT TEMPS/POPS...
DALLAS-FT. WORTH, TX 35 54 34 54 34 / 20 5 0 0 5
WACO, TX 35 61 34 60 33 / 5 0 0 0 5
PARIS, TX 36 49 31 51 31 / 40 5 0 0 5
DENTON, TX 35 53 30 51 31 / 30 5 0 0 5
MCKINNEY, TX 36 52 32 51 32 / 30 5 0 0 5
DALLAS, TX 37 56 35 55 35 / 20 5 0 0 5
TERRELL, TX 36 52 34 54 34 / 10 5 0 0 5
CORSICANA, TX 37 57 35 58 34 / 5 0 0 0 5
TEMPLE, TX 36 63 36 63 33 / 5 0 0 0 5
MINERAL WELLS, TX 34 57 30 54 29 / 40 0 0 0 5
&&
.FWD WATCHES/WARNINGS/ADVISORIES...
WIND ADVISORY UNTIL 4 AM CST TUESDAY FOR TXZ091>095-100>107-
115>123-129>135-141>148-156>162-174-175.
WINTER WEATHER ADVISORY UNTIL MIDNIGHT CST TONIGHT FOR TXZ091-
100-101-115.
&&
$$
/
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
307 PM CST SUN FEB 24 2013
.SHORT TERM...TONIGHT THROUGH WEDNESDAY
306 PM CST SUN FEB 24 2013
CURRENTLY AS OF 21Z...WATER VAPOR LOOP AND RAP 500MB HEIGHT ANALYSIS
SHOWED RIDGING FROM JUST OFF THE CALIFORNIA COAST INTO SOUTHERN
ALBERTA...A POTENT SOUTHERN STREAM UPPER LOW OVER ARIZONA AND NEW
MEXICO...RIDGING BUILDING IN THE SOUTHERN STREAM AHEAD OF IT FROM
THE LOWER MISSISSIPPI RIVER VALLEY INTO OUR FORECAST AREA...AND A
NORTHERN STREAM SHORTWAVE TROUGH CROSSING SOUTH CENTRAL CANADA AND
NORTHWEST NORTH DAKOTA. SUBSIDENCE UNDER THE SOUTHERN STREAM UPPER
RIDGE COMBINED WITH PLENTY OF DRY AIR SEEN ON THE 12Z MPX AND DVN
SOUNDINGS HAS RESULTED IN A DRY DAY ACROSS THE FORECAST AREA.
VARYING CLOUD COVER ACROSS THE AREA. HAD ONE PATCH OF CIRRUS MOVE
ACROSS TOPPING THE RIDGE. MORE IMPORTANTLY...A STRATUS DECK LINGERS
NORTHEAST OF I-94...AND TO THE SOUTHWEST A STRATUS DECK HAS BEEN
EXPANDING NORTHEAST FROM EASTERN NEBRASKA TO AUSTIN MN AND MASON
CITY IA. THE FORMER STRATUS IS RELATED TO MOISTURE STILL TRAPPED
FROM FRIDAYS STORM...EVIDENT ON THE 12Z GRB SOUNDING. THE LATTER
STRATUS IS ALONG AN INVERTED SURFACE TROUGH...WHICH EXTENDS FROM
DEEPENING LOW PRESSURE IN WEST TEXAS INTO SOUTHWEST MN. AIRMASS HAS
WARMED QUITE A BIT WITH 850MB TEMPS OF -5C AT MPX AT 12Z COMPARED TO
-10C AT 12Z YESTERDAY. THIS WARMING HAS BEEN REFLECTED BY
TEMPERATURES IN THE FORECAST AREA ABOUT 5-10 DEGREES WARMER THAN
YESTERDAY.
SHORT TERM HIGHLIGHTS / CONCERNS...
1. POTENTIAL FOR FOG AGAIN TONIGHT AND MONDAY NIGHT -
DEWPOINTS THROUGH MIXING AND SOME PARTIAL SNOW MELTING HAVE RISEN
BACK UP TO AROUND 20 F. COOLING TONIGHT...EVEN UNDER THE STRATUS
DECK EXPANDING NORTHEAST...BRINGS UP THE CONCERN OF FALLING THROUGH
THESE CROSS-OVER TEMPERATURES AND RESULTING IN FOG. SREF
PROBABILITIES OF LESS THAN 1 MILE VISIBILITY AND HRRR VISIBILITY
PROGS INDICATE FOG FORMING AGAIN...AS SOON AS 03Z AND THEN
DISSIPATING BY 15Z. BOTH SUGGEST NORTHEAST IOWA INTO FAR SOUTHWEST
WI AND ACROSS TAYLOR/CLARK COUNTIES AS THE BEST CHANCES FOR FOG. OF
THEM...THINK THE FIRST AREA WOULD HAVE THE BEST CHANCE AS THEY
SHOULD REMAIN CLEAR THE LONGEST AND BE ABLE TO GO THROUGH THE
CROSS-OVER. THERE ARE MID/HIGH CLOUDS ACROSS NEBRASKA PROGGED TO
SPREAD IN DURING THE NIGHT...WHICH SHOULD DISRUPT THE FOG PROCESS.
FEEL THERE IS ENOUGH SIGNAL HERE TO JUST GO WITH PATCHY FREEZING FOG
ACROSS THE ENTIRE AREA TONIGHT...DISSIPATING AFTER MIDNIGHT EXCEPT
OVER TAYLOR/CLARK TO MATCH THE INCOMING MID/HIGH CLOUDS. WOULD NOT
COMPLETELY RULE OUT DENSE FOG EITHER...BUT WOULD LIKE TO SEE
DEWPOINTS RIGHT NOW A LITTLE HIGHER BEFORE MENTIONING DENSE FOG.
LOOKING AHEAD TO MONDAY NIGHT...THE SREF AGAIN POINTS TO POSSIBLE
FOG FORMATION OVER THE NORTH HALF OF WISCONSIN. THERE MIGHT BE A
LITTLE BETTER CHANCE AS MOST MODELS SHOW POTENTIAL FOR PARTIAL
CLEARING AFTER MIDNIGHT. THUS...INCLUDING A MENTION OF PATCHY
FREEZING FOG OVER TAYLOR/CLARK COUNTIES.
2. LIGHT QPF SIGNALS FROM GFS/NAM/REGIONAL CANADIAN/SREF TONIGHT
THROUGH MONDAY NIGHT -
24.12Z NAM/GFS/REGIONAL CANADIAN AND 24.15Z SREF POP FORECASTS HAVE
HIGHLIGHTED AN AREA OF LIGHT QPF POSSIBLE FROM SOUTHERN MN INTO THE
NORTH HALF OF WI TONIGHT THROUGH MONDAY NIGHT. THIS LIGHT
PRECIPITATION IS RELATED TO MOISTURE STUCK AT OR BELOW 900 MB AND
WEAK LIFT GETS APPLIED TO IT. THE MOISTURE IS DEFINITELY THERE NOTED
BY THAT STRATUS DECK ALREADY OVER NORTHWEST IOWA. THE LIFT COMES
FROM TWO FEATURES. THE FIRST IS A SURFACE TROUGH ACCOMPANYING THE
CURRENT SHORTWAVE TROUGH TRACKING ACROSS SOUTH CENTRAL CANADA...
WHICH APPROACHES THE AREA MONDAY NIGHT. THE SECOND IS THAT INVERTED
TROUGH WHICH IS PROGGED TO LINGER OVER WESTERN IOWA AND SOUTHWEST
MINNESOTA. SHOULD THIS PRECIPITATION OCCUR...WE COULD BE DEALING
WITH FLURRIES AND/OR FREEZING DRIZZLE...WITH THE LATTER FAVORED MORE
FOR MONDAY NIGHT WHEN NO ICE IS PRESENT ALOFT. HOWEVER...FEEL THIS
WEAK LIFT IS OVERDONE. MOST OF THESE MODELS SUGGEST THERE SHOULD
HAVE PRECIPITATION ALREADY AND THERE HAS NOT BEEN. ADDITIONALLY...
THERE IS BASICALLY NO ISENTROPIC LIFT TO SPEAK OF ALONG THE INVERTED
TROUGH. THUS...THINKING THE LIGHT QPF MIGHT BE MORE OF A SIGNAL FOR
THE LOW CLOUDS AND FOG POTENTIAL...AND THERE WAS FOG THIS MORNING.
SO HAVE KEPT THE FORECAST DRY FOR NOW FOR TONIGHT THROUGH MONDAY
NIGHT.
3. THE SOUTHERN STREAM UPPER LOW AND DEVELOPING WINTER STORM -
MODEL TRENDS...FLIP-FLOPPING CONTINUES ON WHETHER OR NOT THE
DEFORMATION BAND ON THE NORTHWEST SIDE OF THE STORM IMPACTS PORTIONS
OF THE AREA FOR TUESDAY INTO TUESDAY NIGHT. THERE APPEARS TO BE 2
REASONS FOR THIS...ONE ON HOW MUCH THE UPPER LOW WILL DECAY AS IT
RUNS INTO THE DOWNSTREAM UPPER RIDGE...AND THE SECOND RELATED TO A
KICKER SHORTWAVE DROPPING INTO NEW MEXICO ON TUESDAY ALONG WITH THE
WAVELENGTH BETWEEN IT AND THE UPPER LOW. THE LATEST EXAMPLE OF
FLIP-FLOPPING IS THE 24.12Z NAM...WHICH THE PREVIOUS 2 RUNS WENT
MORE SOUTHEAST AND BASICALLY HAD THE AREA DRY. NOW THE 24.12Z NAM
SHIFTED NORTHWEST... PRODUCING 0.50 TO 1 INCH OF LIQUID EQUIVALENT
FROM FAYETTE COUNTY EAST TO GRANT COUNTY. THIS WOULD EASILY BE
WORTHY OF AN ADVISORY AND POSSIBLY A WARNING. LATEST 24.18Z NAM IS
SIMILAR TO THE 12Z BUT CAME DOWN A BIT QPF WISE. THE GFS HAS BEEN
ONE OF THE MORE STABLE MODELS WITH THE PAST 6 TO 8 RUNS STAYING
FAIRLY CONSISTENT...BRINGING THE BAND INTO THE SOUTHEAST 1/2 OF THE
AREA TUESDAY AFTERNOON AND LINGERING IT INTO THE DAY WEDNESDAY. THE
QPF IS NOT NEARLY AS HEAVY AS THE NAM...UP TO 0.40 INCHES...BUT
WOULD BE ADVISORY WORTHY. THE LAST FEW CANADIAN RUNS INCLUDING THE
LATEST 24.12Z RUN HAVE BEEN SIMILAR TO THE GFS. LASTLY...THE 24.12Z
RUN OF THE ECMWF SHIFTED BACK TO THE NORTHWEST TOWARDS ITS 23.12Z
RUN...COMING MORE IN-LINE WITH THE GFS AND SAYING THAT THE 24.00Z
RUN WAS A FLUKE.
FOR THE FORECAST...SINCE THE 24.12Z MODELS ARE IN PRETTY GOOD
AGREEMENT THAT OUR SOUTHEAST END WILL BE IMPACTED TUESDAY INTO
TUESDAY NIGHT...AND GIVEN THE MORE STABLE NATURE OF THE GFS/CANADIAN
IMPACTING THE SAME AREA...HAVE RAISED PRECIPITATION CHANCES. NOW THE
SYSTEM AS IT LIFTS OUT OF THE SOUTHERN PLAINS AND INTO ILLINOIS WILL
BE WEAKENING...DUE TO IT RUNNING INTO THE RIDGING BUILT UP AHEAD OF
IT AS MENTIONED EARLIER AND THE SYSTEM GOING THROUGH THE OCCLUSION
PROCESS. THUS...THE IDEA MODELS HAVE SUGGESTED OF QPF DIMINISHING
DUE TO WEAKENING FORCING ALOFT SEEMS REASONABLE. SO AT THIS TIME...
ONLY THINKING MAYBE A MINIMAL ADVISORY WOULD BE NEEDED AT MOST...FOR
FAYETTE COUNTY EAST TO GRANT COUNTY. THINGS COULD STILL CHANGE...
THOUGH. THE NORTHWEST HALF OF THE FORECAST AREA MAY NOT GET MUCH IF
ANYTHING OUT OF THIS BRUSH BY FROM THE STORM...BUT THE CYCLONIC FLOW
AND MOISTURE WRAPPING AROUND WARRANTS KEEPING SOME 20-40
PRECIPITATION CHANCES. THESE CHANCES GO INTO WEDNESDAY...THOUGH THE
24.12Z ECMWF/CANADIAN WOULD SUGGEST THE PRECIPITATION COULD END
FASTER WEST TO EAST.
OUTSIDE THE ISSUES NOTED ABOVE...DESPITE THE APPROACH OF THE STORM
SYSTEM...HIGH TEMPERATURES SHOULD CLIMB UP TO AROUND NORMAL. PART OF
THIS IS DUE TO THE 925MB TEMPS HOLDING AROUND -4C EACH DAY...ABOUT 2
C WARMER THAN TODAY. THE SECOND IS THAT EVEN IF WE HAVE TO DEAL WITH
CLOUD ISSUES...THE HIGHER SUN ANGLE CAN HELP MIX BETTER NOW. MEDFORD
WI IS A GOOD EXAMPLE TODAY MANAGING TO HIT 30F DESPITE HAVING LOW
CLOUDS AROUND ALL DAY AND 925MB TEMPS AROUND -6C.
.LONG TERM...WEDNESDAY NIGHT THROUGH SUNDAY
306 PM CST SUN FEB 24 2013
THE LONG TERM FORECAST CONTINUES TO LOOK QUIET. GOOD MODEL AGREEMENT
CONTINUES AMONGST THE 24.12Z ECMWF/GFS/CANADIAN AND ECMWF
ENSEMBLES...WHICH SHOW RIDGING BUILDING UP OVER THE WESTERN U.S.
THROUGH SATURDAY WHILE TROUGHING HANGS IN PLACE OVER THE EASTERN
U.S.. THE FORECAST AREA IS CAUGHT IN THE MIDDLE BETWEEN THE
TWO...FAVORING A RIDGE OF HIGH PRESSURE WHICH SLOWLY BUILDS EAST
INTO THE FORECAST AREA DURING THIS PERIOD. THERE ARE INDICATIONS OF
A SHORTWAVE TROUGH DROPPING SOUTH THROUGH THE AREA ON FRIDAY...BUT
THERE ARE BOTH UNCERTAINTIES EXACTLY ON WHERE IT TRACKS AND WHETHER
IT WILL HAVE ENOUGH MOISTURE TO PRODUCE PRECIPITATION. THEREFORE...
AFTER SOME LINGERING SMALL PRECIPITATION CHANCES OVER WISCONSIN
AREAS WEDNESDAY NIGHT ASSOCIATED WITH THE SLOWLY DEPARTING AND
WEAKENING STORM TO OUR EAST...HAVE A DRY FORECAST FOR THURSDAY INTO
SATURDAY. HEADING INTO SUNDAY...A MORE POTENT SHORTWAVE TROUGH LOOKS
TO CRASH THROUGH THE WESTERN U.S. RIDGE...BUT ONLY MAKE IT INTO THE
NORTHERN ROCKIES BY 00Z MONDAY. IT SHOULD BE ENOUGH TO PUSH SOME OF
THE UPPER RIDGE EAST...ALLOWING THE SURFACE HIGH PRESSURE RIDGE TO
AT LEAST MOVE OVER IF NOT SHIFT OFF TO THE EAST FORECAST AREA.
NEEDLESS TO SAY...ANOTHER DRY DAY IS ANTICIPATED SUNDAY.
TEMPERATURES ARE A LITTLE TOUGH GIVEN A NORTHERLY FLOW PRESENT WHICH
BRINGS DOWN SOME COOLER AIR FOR MUCH OF THE PERIOD. HOWEVER...IT IS
NOT THAT COLD...NOTED BY 850MB TEMPS AT MOST DROPPING TO -8 TO -12C
BY FRIDAY. ANY SUNSHINE THAT OCCURS...WHICH MORE COULD HAPPEN IF THE
ECMWF IS RIGHT...WILL ALLOW FOR GOOD MIXING. THUS HAVE LEFT A
CONSENSUS APPROACH WHICH YIELDS HIGHS JUST SLIGHTLY BELOW NORMAL.
&&
.AVIATION...THROUGH 18Z MONDAY
1143 AM CST SUN FEB 24 2013
MAIN AVIATION CONCERNS ARE ON AN AREA OF IFR/MVFR
STRATUS...CURRENTLY OVER MUCH OF WESTERN IOWA...EXPANDING
NORTHEAST THIS AFTERNOON INTO THIS EVENING. THE STRATUS DECK IS
EXPECTED TO MOVE OVER KRST BY 2130Z THIS AFTERNOON WITH CEILINGS
LOWERING TO 1500FT...THEN LOWERING FURTHER TO 500 FT BY 00Z.
ALSO...THERE ARE VISIBILITY RESTRICTIONS OCCURRING UNDER THIS SO
PLAN ON VISIBILITIES LOWERING TO 4SM. CONDITIONS WILL CONTINUE TO
DETERIORATE THROUGH THE EVENING HOURS AND BY 03Z CEILINGS LOOK TO
LOWER TO 200FT WITH VISIBILITIES LOWERING TO 3SM. THESE CONDITIONS
WILL PERSIST AT KRST THROUGH THE OVERNIGHT HOURS WITH IMPROVEMENTS
EXPECTED AROUND 14Z. THE BULK OF THE STRATUS DECK SHOULD REMAIN
JUST NORTHEAST OF KLSE THROUGH THE EVENING HOURS...THEN
POTENTIALLY EXPANDING TO THE SOUTHEAST. PLAN ON CEILINGS LOWERING
TO 1500 FT AT KLSE AROUND 11Z. WINDS WILL BE LIGHT AND GENERALLY
OUT OF THE SOUTH/SOUTHEAST THROUGH THE FORECAST PERIOD AT 3 TO 7
KTS.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
306 PM CST SUN FEB 24 2013
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
SHORT TERM...AJ
LONG TERM...AJ
AVIATION...WETENKAMP
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
1143 AM CST SUN FEB 24 2013
.SHORT TERM...TODAY THROUGH TUESDAY NIGHT
318 AM CST SUN FEB 24 2013
THE MAIN FOCUS THROUGH THE EARLY PART OF NEXT WEEK IS WITH THE
NEXT STORM SYSTEM THAT WILL TRACK INTO THE REGION AND BRING THE
POSSIBILITY OF SOME SNOW ALONG WITH IT.
CURRENTLY...SKIES HAVE CLEARED THROUGH MUCH OF THE REGION WITH THE
MAIN EXCEPTION BEING ACROSS NORTHERN WISCONSIN WHERE AN INVERTED
SURFACE TROUGH LINGERS NEAR THE UPPER GREAT LAKES. A SURFACE RIDGE
AXIS RUNS FROM THE TRIPLE POINT OF NORTH/SOUTH DAKOTA AND
MINNESOTA DOWN INTO CENTRAL ILLINOIS AND IS WHERE TEMPERATURES
HAVE DROPPED ENOUGH TO PRODUCE SOME POCKETS OF SHALLOW GROUND FOG.
A FEW SITES IN SOUTHEAST MINNESOTA AND NORTHEAST IOWA HAVE BRIEFLY
GONE DOWN TO A 1/2SM...BUT HAVE JUST AS QUICKLY IMPROVED DUE TO
THE SHALLOW NATURE OF THIS FOG. WITH THE 24.07Z RAP SHOWING THIS
RIDGE AXIS NOT MAKING IT EAST OF THE RIVER UNTIL MID MORNING...AM
NOT EXPECTING MUCH IN THE WAY OF WIDESPREAD FOG IN THIS REGION.
MAY HAVE TO TRIM BACK SOME OF THE FREEZING FOG ADVISORY OVER THE
NEXT FEW HOURS WITH THE CHOPPING BLOCK LIKELY BEING WITH ANY
COUNTIES ALONG AND EAST OF THE MISSISSIPPI RIVER. EVEN IN THE
AREAS WHERE THE FOG DOES OCCUR...IMPACTS ARE EXPECTED TO BE
MINIMAL WITH THE SHORT DURATION OF IT...IF IT EVEN OCCURS. WITH
THE RIDGE AXIS OVER THE REGION TODAY...EXPECT A DECENT DAY WITH
MAINLY SUNNY SKIES AND HIGHS RIGHT AROUND NORMAL.
THIS RIDGE AXIS WILL LINGER ACROSS THE UPPER MISSISSIPPI RIVER
VALLEY INTO MONDAY BEFORE THE NEXT SYSTEM MOVES IN FROM THE
SOUTHWEST AND ESCORTS IT OFF TO THE NORTH BY TUESDAY. THE TREND
FOR THIS NEXT SYSTEM APPEARS TO STILL BE THE SAME WITH THE MORE
SOUTHERLY TRACK THAT KEEPS MUCH OF THE HEAVIER SNOW TO THE SOUTH
OF THE FORECAST AREA. THE 24.00Z NAM/GFS/ECMWF ARE ALL FAIRLY
CLOSE WITH THE TRACK AND TIMING OF THE LOW RUNNING FROM SOUTH
CENTRAL MISSOURI TUESDAY MORNING ON INTO CENTRAL INDIANA BY
TUESDAY EVENING. THE 24.00Z NAM SEEMS TO BE A LITTLE UNDERDONE ON
ITS QPF AS BUFKIT SOUNDINGS OUT OF DBQ SHOW A FULLY SATURATED
SOUNDING FROM LATE TUESDAY AFTERNOON INTO THE OVERNIGHT HOURS BUT
QPF IS 0.00 THERE. HOWEVER...JUST TO THE NORTHWEST OF THAT AREA AT
ALO AND BLR...THESE SAME SOUNDINGS SHOW A SUBSTANTIAL DRY LAYER
THAT WILL NEED TO BE OVERCOME FROM THE SURFACE ON UP TO 700MB. DUE
TO THIS DRY LAYER...AM CONCERNED THAT THE SNOW FROM THIS SYSTEM
MAY NOT MAKE IT VERY FAR TO THE NORTHWEST OF THE MAIN BAND THAT IS
EXPECTED TO BE IN EASTERN IOWA/NORTHERN ILLINOIS. HAVE KEPT THE
CHANCES FOR SNOW GOING FOR THE TIME BEING...BUT THEY MAY HAVE TO
GET TRIMMED BACK IF THE 24.00Z NAM/ECMWF SOUTHEAST TREND HOLDS
FIRM.
.LONG TERM...WEDNESDAY THROUGH SATURDAY
318 AM CST SUN FEB 24 2013
CONFIDENCE IS SOMEWHAT LOW WITH HOW LONG THE LIGHT SNOW MAY HOLD
ON ACROSS THE REGION AS THE TAIL END OF THE SYSTEM MOVES THROUGH.
THERE ARE DIFFERING OPINIONS ON WHERE THE INVERTED SURFACE TROUGH
SETS UP WITH THE 24.00Z ECMWF KEEPING THE AREA DRY THROUGH THE
REST OF THE WEEK WHILE THE 24.00Z GFS/GEM KEEPS SOME LIGHT SNOW IN
THROUGH THURSDAY. KEPT SOME SMALL CHANCES IN THERE FOR NOW INTO
EARLY THURSDAY MORNING...BUT AS MENTIONED FOR TUESDAY...CONFIDENCE
IN HOW FAR NORTHWEST THE SNOW MAKES IT IS PRETTY LOW AT THIS
POINT. DESPITE NORTHERLY FLOW ALOFT AND AT THE SURFACE...THERE IS
NOT MUCH OF A COLD SOURCE OF AN AIR MASS ACROSS CANADA TO PULL ANY
COLD AIR DOWN FROM...SO TEMPERATURES WILL REMAIN AT OR JUST BELOW
NORMAL THROUGH MUCH OF THE NEXT WEEK.
&&
.AVIATION...THROUGH 18Z MONDAY
1143 AM CST SUN FEB 24 2013
MAIN AVIATION CONCERNS ARE ON AN AREA OF IFR/MVFR
STRATUS...CURRENTLY OVER MUCH OF WESTERN IOWA...EXPANDING
NORTHEAST THIS AFTERNOON INTO THIS EVENING. THE STRATUS DECK IS
EXPECTED TO MOVE OVER KRST BY 2130Z THIS AFTERNOON WITH CEILINGS
LOWERING TO 1500FT...THEN LOWERING FURTHER TO 500 FT BY 00Z.
ALSO...THERE ARE VISIBILITY RESTRICTIONS OCCURRING UNDER THIS SO
PLAN ON VISIBILITIES LOWERING TO 4SM. CONDITIONS WILL CONTINUE TO
DETERIORATE THROUGH THE EVENING HOURS AND BY 03Z CEILINGS LOOK TO
LOWER TO 200FT WITH VISIBILITIES LOWERING TO 3SM. THESE CONDITIONS
WILL PERSIST AT KRST THROUGH THE OVERNIGHT HOURS WITH IMPROVEMENTS
EXPECTED AROUND 14Z. THE BULK OF THE STRATUS DECK SHOULD REMAIN
JUST NORTHEAST OF KLSE THROUGH THE EVENING HOURS...THEN
POTENTIALLY EXPANDING TO THE SOUTHEAST. PLAN ON CEILINGS LOWERING
TO 1500 FT AT KLSE AROUND 11Z. WINDS WILL BE LIGHT AND GENERALLY
OUT OF THE SOUTH/SOUTHEAST THROUGH THE FORECAST PERIOD AT 3 TO 7
KTS.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
725 AM CST SUN FEB 24 2013
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
SHORT TERM...HALBACH/RRS
LONG TERM....HALBACH
AVIATION...WETENKAMP
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
725 AM CST SUN FEB 24 2013
.SHORT TERM...TODAY THROUGH TUESDAY NIGHT
725 AM CST SUN FEB 24 2013
HAVE UPDATED GRIDS/ZONES AND CANCELLED THE REST OF THE FREEZING FOG
ADVISORY. FOG REMAINS VERY PATCHY...EVEN ACROSS THE SOUTHWEST END OF
THE FCST AREA...WITH NO RIMING/HOAR FROST/SLIPPERY ROAD CONDITIONS
REPORTED. THEREFORE LET THE REST OF THE ADVISORY GO. FOG AT KLSE IS
VERY LOCAL AND SHALLOW...CONFINED TO THE AIRPORT ITSELF. OFFICE WEB
CAM AND OTHER LOCAL REPORTS SHOW/INDICATE ONLY MINOR HAZE IN THE
REST OF THE NEARBY MS AND LSE RIVER VALLEYS. WHAT FOG IT AT KLSE
SHOULD BURN OFF RATHER QUICKLY NOW THAT THE SUN IS UP.
REMAINDER OF 318 AM SHORT-TERM DISCUSSION FOLLOWS.
THE MAIN FOCUS THROUGH THE EARLY PART OF NEXT WEEK IS WITH THE
NEXT STORM SYSTEM THAT WILL TRACK INTO THE REGION AND BRING THE
POSSIBILITY OF SOME SNOW ALONG WITH IT.
CURRENTLY...SKIES HAVE CLEARED THROUGH MUCH OF THE REGION WITH THE
MAIN EXCEPTION BEING ACROSS NORTHERN WISCONSIN WHERE AN INVERTED
SURFACE TROUGH LINGERS NEAR THE UPPER GREAT LAKES. A SURFACE RIDGE
AXIS RUNS FROM THE TRIPLE POINT OF NORTH/SOUTH DAKOTA AND
MINNESOTA DOWN INTO CENTRAL ILLINOIS AND IS WHERE TEMPERATURES
HAVE DROPPED ENOUGH TO PRODUCE SOME POCKETS OF SHALLOW GROUND FOG.
A FEW SITES IN SOUTHEAST MINNESOTA AND NORTHEAST IOWA HAVE BRIEFLY
GONE DOWN TO A 1/2SM...BUT HAVE JUST AS QUICKLY IMPROVED DUE TO
THE SHALLOW NATURE OF THIS FOG. WITH THE 24.07Z RAP SHOWING THIS
RIDGE AXIS NOT MAKING IT EAST OF THE RIVER UNTIL MID MORNING...AM
NOT EXPECTING MUCH IN THE WAY OF WIDESPREAD FOG IN THIS REGION.
MAY HAVE TO TRIM BACK SOME OF THE FREEZING FOG ADVISORY OVER THE
NEXT FEW HOURS WITH THE CHOPPING BLOCK LIKELY BEING WITH ANY
COUNTIES ALONG AND EAST OF THE MISSISSIPPI RIVER. EVEN IN THE
AREAS WHERE THE FOG DOES OCCUR...IMPACTS ARE EXPECTED TO BE
MINIMAL WITH THE SHORT DURATION OF IT...IF IT EVEN OCCURS. WITH
THE RIDGE AXIS OVER THE REGION TODAY...EXPECT A DECENT DAY WITH
MAINLY SUNNY SKIES AND HIGHS RIGHT AROUND NORMAL.
THIS RIDGE AXIS WILL LINGER ACROSS THE UPPER MISSISSIPPI RIVER
VALLEY INTO MONDAY BEFORE THE NEXT SYSTEM MOVES IN FROM THE
SOUTHWEST AND ESCORTS IT OFF TO THE NORTH BY TUESDAY. THE TREND
FOR THIS NEXT SYSTEM APPEARS TO STILL BE THE SAME WITH THE MORE
SOUTHERLY TRACK THAT KEEPS MUCH OF THE HEAVIER SNOW TO THE SOUTH
OF THE FORECAST AREA. THE 24.00Z NAM/GFS/ECMWF ARE ALL FAIRLY
CLOSE WITH THE TRACK AND TIMING OF THE LOW RUNNING FROM SOUTH
CENTRAL MISSOURI TUESDAY MORNING ON INTO CENTRAL INDIANA BY
TUESDAY EVENING. THE 24.00Z NAM SEEMS TO BE A LITTLE UNDERDONE ON
ITS QPF AS BUFKIT SOUNDINGS OUT OF DBQ SHOW A FULLY SATURATED
SOUNDING FROM LATE TUESDAY AFTERNOON INTO THE OVERNIGHT HOURS BUT
QPF IS 0.00 THERE. HOWEVER...JUST TO THE NORTHWEST OF THAT AREA AT
ALO AND BLR...THESE SAME SOUNDINGS SHOW A SUBSTANTIAL DRY LAYER
THAT WILL NEED TO BE OVERCOME FROM THE SURFACE ON UP TO 700MB. DUE
TO THIS DRY LAYER...AM CONCERNED THAT THE SNOW FROM THIS SYSTEM
MAY NOT MAKE IT VERY FAR TO THE NORTHWEST OF THE MAIN BAND THAT IS
EXPECTED TO BE IN EASTERN IOWA/NORTHERN ILLINOIS. HAVE KEPT THE
CHANCES FOR SNOW GOING FOR THE TIME BEING...BUT THEY MAY HAVE TO
GET TRIMMED BACK IF THE 24.00Z NAM/ECMWF SOUTHEAST TREND HOLDS
FIRM.
.LONG TERM...WEDNESDAY THROUGH SATURDAY
318 AM CST SUN FEB 24 2013
CONFIDENCE IS SOMEWHAT LOW WITH HOW LONG THE LIGHT SNOW MAY HOLD
ON ACROSS THE REGION AS THE TAIL END OF THE SYSTEM MOVES THROUGH.
THERE ARE DIFFERING OPINIONS ON WHERE THE INVERTED SURFACE TROUGH
SETS UP WITH THE 24.00Z ECMWF KEEPING THE AREA DRY THROUGH THE
REST OF THE WEEK WHILE THE 24.00Z GFS/GEM KEEPS SOME LIGHT SNOW IN
THROUGH THURSDAY. KEPT SOME SMALL CHANCES IN THERE FOR NOW INTO
EARLY THURSDAY MORNING...BUT AS MENTIONED FOR TUESDAY...CONFIDENCE
IN HOW FAR NORTHWEST THE SNOW MAKES IT IS PRETTY LOW AT THIS
POINT. DESPITE NORTHERLY FLOW ALOFT AND AT THE SURFACE...THERE IS
NOT MUCH OF A COLD SOURCE OF AN AIR MASS ACROSS CANADA TO PULL ANY
COLD AIR DOWN FROM...SO TEMPERATURES WILL REMAIN AT OR JUST BELOW
NORMAL THROUGH MUCH OF THE NEXT WEEK.
&&
.AVIATION...TODAY AND TONIGHT
545 AM CST SUN FEB 24 2013
MAIN WEATHER CONCERN AT BOTH TAF SITES THRU TONIGHT IS FZFG THRU
15-16Z THIS MORNING. AFTER THAT...MAINLY MID/HIGH CLOUDS AOA 10K FT
TO STREAM ACROSS THE AREA THRU THIS AFTERNOON/TONIGHT...ALONG WITH
LIGHT/VARIABLE WINDS.
AS FOR THE EARLY MORNING FOG...FZFG AT KLSE APPEARS TO BE VERY LOCAL
AND/OR SHALLOW. OFFICE WEB CAM AND VIEW FROM THE OFFICE OFF THE
BLUFF TOP SHOW NO OTHER FOG IN EITHER THE MS VALLEY OR LSE RIVER
VALLEY. EXPECT VSBYS AT KLSE TO BOUNCE AROUND THRU 15Z AS LIGHT
WINDS PUSH WHATEVER FOG IS ON/NEAR THE AIRFIELD AROUND A BIT. WITH
THE FOG SEEMINGLY SHALLOW...IT SHOULD BURN OFF RATHER QUICKLY THIS
MORNING.
AT KRST...DESPITE THREAT OF FZFG VSBYS AT KRST HAVE REMAIN VFR SINCE
MIDNIGHT. ONLY CARRIED A TEMPO 3SM BR AT KRST THRU 14Z WITH SOME
PATCHY MVFR BR ELSEWHERE ACROSS THE HIGHER TERRAIN OF SOUTHEAST MN.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
725 AM CST SUN FEB 24 2013
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
SHORT TERM...HALBACH/RRS
LONG TERM....HALBACH
AVIATION.....RRS
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
545 AM CST SUN FEB 24 2013
.SHORT TERM...TODAY THROUGH TUESDAY NIGHT
318 AM CST SUN FEB 24 2013
THE MAIN FOCUS THROUGH THE EARLY PART OF NEXT WEEK IS WITH THE
NEXT STORM SYSTEM THAT WILL TRACK INTO THE REGION AND BRING THE
POSSIBILITY OF SOME SNOW ALONG WITH IT.
CURRENTLY...SKIES HAVE CLEARED THROUGH MUCH OF THE REGION WITH THE
MAIN EXCEPTION BEING ACROSS NORTHERN WISCONSIN WHERE AN INVERTED
SURFACE TROUGH LINGERS NEAR THE UPPER GREAT LAKES. A SURFACE RIDGE
AXIS RUNS FROM THE TRIPLE POINT OF NORTH/SOUTH DAKOTA AND
MINNESOTA DOWN INTO CENTRAL ILLINOIS AND IS WHERE TEMPERATURES
HAVE DROPPED ENOUGH TO PRODUCE SOME POCKETS OF SHALLOW GROUND FOG.
A FEW SITES IN SOUTHEAST MINNESOTA AND NORTHEAST IOWA HAVE BRIEFLY
GONE DOWN TO A 1/2SM...BUT HAVE JUST AS QUICKLY IMPROVED DUE TO
THE SHALLOW NATURE OF THIS FOG. WITH THE 24.07Z RAP SHOWING THIS
RIDGE AXIS NOT MAKING IT EAST OF THE RIVER UNTIL MID MORNING...AM
NOT EXPECTING MUCH IN THE WAY OF WIDESPREAD FOG IN THIS REGION.
MAY HAVE TO TRIM BACK SOME OF THE FREEZING FOG ADVISORY OVER THE
NEXT FEW HOURS WITH THE CHOPPING BLOCK LIKELY BEING WITH ANY
COUNTIES ALONG AND EAST OF THE MISSISSIPPI RIVER. EVEN IN THE
AREAS WHERE THE FOG DOES OCCUR...IMPACTS ARE EXPECTED TO BE
MINIMAL WITH THE SHORT DURATION OF IT...IF IT EVEN OCCURS. WITH
THE RIDGE AXIS OVER THE REGION TODAY...EXPECT A DECENT DAY WITH
MAINLY SUNNY SKIES AND HIGHS RIGHT AROUND NORMAL.
THIS RIDGE AXIS WILL LINGER ACROSS THE UPPER MISSISSIPPI RIVER
VALLEY INTO MONDAY BEFORE THE NEXT SYSTEM MOVES IN FROM THE
SOUTHWEST AND ESCORTS IT OFF TO THE NORTH BY TUESDAY. THE TREND
FOR THIS NEXT SYSTEM APPEARS TO STILL BE THE SAME WITH THE MORE
SOUTHERLY TRACK THAT KEEPS MUCH OF THE HEAVIER SNOW TO THE SOUTH
OF THE FORECAST AREA. THE 24.00Z NAM/GFS/ECMWF ARE ALL FAIRLY
CLOSE WITH THE TRACK AND TIMING OF THE LOW RUNNING FROM SOUTH
CENTRAL MISSOURI TUESDAY MORNING ON INTO CENTRAL INDIANA BY
TUESDAY EVENING. THE 24.00Z NAM SEEMS TO BE A LITTLE UNDERDONE ON
ITS QPF AS BUFKIT SOUNDINGS OUT OF DBQ SHOW A FULLY SATURATED
SOUNDING FROM LATE TUESDAY AFTERNOON INTO THE OVERNIGHT HOURS BUT
QPF IS 0.00 THERE. HOWEVER...JUST TO THE NORTHWEST OF THAT AREA AT
ALO AND BLR...THESE SAME SOUNDINGS SHOW A SUBSTANTIAL DRY LAYER
THAT WILL NEED TO BE OVERCOME FROM THE SURFACE ON UP TO 700MB. DUE
TO THIS DRY LAYER...AM CONCERNED THAT THE SNOW FROM THIS SYSTEM
MAY NOT MAKE IT VERY FAR TO THE NORTHWEST OF THE MAIN BAND THAT IS
EXPECTED TO BE IN EASTERN IOWA/NORTHERN ILLINOIS. HAVE KEPT THE
CHANCES FOR SNOW GOING FOR THE TIME BEING...BUT THEY MAY HAVE TO
GET TRIMMED BACK IF THE 24.00Z NAM/ECMWF SOUTHEAST TREND HOLDS
FIRM.
.LONG TERM...WEDNESDAY THROUGH SATURDAY
318 AM CST SUN FEB 24 2013
CONFIDENCE IS SOMEWHAT LOW WITH HOW LONG THE LIGHT SNOW MAY HOLD
ON ACROSS THE REGION AS THE TAIL END OF THE SYSTEM MOVES THROUGH.
THERE ARE DIFFERING OPINIONS ON WHERE THE INVERTED SURFACE TROUGH
SETS UP WITH THE 24.00Z ECMWF KEEPING THE AREA DRY THROUGH THE
REST OF THE WEEK WHILE THE 24.00Z GFS/GEM KEEPS SOME LIGHT SNOW IN
THROUGH THURSDAY. KEPT SOME SMALL CHANCES IN THERE FOR NOW INTO
EARLY THURSDAY MORNING...BUT AS MENTIONED FOR TUESDAY...CONFIDENCE
IN HOW FAR NORTHWEST THE SNOW MAKES IT IS PRETTY LOW AT THIS
POINT. DESPITE NORTHERLY FLOW ALOFT AND AT THE SURFACE...THERE IS
NOT MUCH OF A COLD SOURCE OF AN AIR MASS ACROSS CANADA TO PULL ANY
COLD AIR DOWN FROM...SO TEMPERATURES WILL REMAIN AT OR JUST BELOW
NORMAL THROUGH MUCH OF THE NEXT WEEK.
&&
.AVIATION...TODAY AND TONIGHT
545 AM CST SUN FEB 24 2013
MAIN WEATHER CONCERN AT BOTH TAF SITES THRU TONIGHT IS FZFG THRU
15-16Z THIS MORNING. AFTER THAT...MAINLY MID/HIGH CLOUDS AOA 10K FT
TO STREAM ACROSS THE AREA THRU THIS AFTERNOON/TONIGHT...ALONG WITH
LIGHT/VARIABLE WINDS.
AS FOR THE EARLY MORNING FOG...FZFG AT KLSE APPEARS TO BE VERY LOCAL
AND/OR SHALLOW. OFFICE WEB CAM AND VIEW FROM THE OFFICE OFF THE
BLUFF TOP SHOW NO OTHER FOG IN EITHER THE MS VALLEY OR LSE RIVER
VALLEY. EXPECT VSBYS AT KLSE TO BOUNCE AROUND THRU 15Z AS LIGHT
WINDS PUSH WHATEVER FOG IS ON/NEAR THE AIRFIELD AROUND A BIT. WITH
THE FOG SEEMINGLY SHALLOW...IT SHOULD BURN OFF RATHER QUICKLY THIS
MORNING.
AT KRST...DESPITE THREAT OF FZFG VSBYS AT KRST HAVE REMAIN VFR SINCE
MIDNIGHT. ONLY CARRIED A TEMPO 3SM BR AT KRST THRU 14Z WITH SOME
PATCHY MVFR BR ELSEWHERE ACROSS THE HIGHER TERRAIN OF SOUTHEAST MN.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
545 AM CST SUN FEB 24 2013
WI...NONE.
MN...FREEZING FOG ADVISORY UNTIL 9 AM CST THIS MORNING FOR MNZ086-
094.
IA...FREEZING FOG ADVISORY UNTIL 9 AM CST THIS MORNING FOR IAZ008-
009-018-019.
&&
$$
SHORT TERM...HALBACH
LONG TERM...HALBACH
AVIATION...BOYNE
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
318 AM CST SUN FEB 24 2013
.SHORT TERM...TODAY THROUGH TUESDAY NIGHT
318 AM CST SUN FEB 24 2013
THE MAIN FOCUS THROUGH THE EARLY PART OF NEXT WEEK IS WITH THE
NEXT STORM SYSTEM THAT WILL TRACK INTO THE REGION AND BRING THE
POSSIBILITY OF SOME SNOW ALONG WITH IT.
CURRENTLY...SKIES HAVE CLEARED THROUGH MUCH OF THE REGION WITH THE
MAIN EXCEPTION BEING ACROSS NORTHERN WISCONSIN WHERE AN INVERTED
SURFACE TROUGH LINGERS NEAR THE UPPER GREAT LAKES. A SURFACE RIDGE
AXIS RUNS FROM THE TRIPLE POINT OF NORTH/SOUTH DAKOTA AND
MINNESOTA DOWN INTO CENTRAL ILLINOIS AND IS WHERE TEMPERATURES
HAVE DROPPED ENOUGH TO PRODUCE SOME POCKETS OF SHALLOW GROUND FOG.
A FEW SITES IN SOUTHEAST MINNESOTA AND NORTHEAST IOWA HAVE BRIEFLY
GONE DOWN TO A 1/2SM...BUT HAVE JUST AS QUICKLY IMPROVED DUE TO
THE SHALLOW NATURE OF THIS FOG. WITH THE 24.07Z RAP SHOWING THIS
RIDGE AXIS NOT MAKING IT EAST OF THE RIVER UNTIL MID MORNING...AM
NOT EXPECTING MUCH IN THE WAY OF WIDESPREAD FOG IN THIS REGION.
MAY HAVE TO TRIM BACK SOME OF THE FREEZING FOG ADVISORY OVER THE
NEXT FEW HOURS WITH THE CHOPPING BLOCK LIKELY BEING WITH ANY
COUNTIES ALONG AND EAST OF THE MISSISSIPPI RIVER. EVEN IN THE
AREAS WHERE THE FOG DOES OCCUR...IMPACTS ARE EXPECTED TO BE
MINIMAL WITH THE SHORT DURATION OF IT...IF IT EVEN OCCURS. WITH
THE RIDGE AXIS OVER THE REGION TODAY...EXPECT A DECENT DAY WITH
MAINLY SUNNY SKIES AND HIGHS RIGHT AROUND NORMAL.
THIS RIDGE AXIS WILL LINGER ACROSS THE UPPER MISSISSIPPI RIVER
VALLEY INTO MONDAY BEFORE THE NEXT SYSTEM MOVES IN FROM THE
SOUTHWEST AND ESCORTS IT OFF TO THE NORTH BY TUESDAY. THE TREND
FOR THIS NEXT SYSTEM APPEARS TO STILL BE THE SAME WITH THE MORE
SOUTHERLY TRACK THAT KEEPS MUCH OF THE HEAVIER SNOW TO THE SOUTH
OF THE FORECAST AREA. THE 24.00Z NAM/GFS/ECMWF ARE ALL FAIRLY
CLOSE WITH THE TRACK AND TIMING OF THE LOW RUNNING FROM SOUTH
CENTRAL MISSOURI TUESDAY MORNING ON INTO CENTRAL INDIANA BY
TUESDAY EVENING. THE 24.00Z NAM SEEMS TO BE A LITTLE UNDERDONE ON
ITS QPF AS BUFKIT SOUNDINGS OUT OF DBQ SHOW A FULLY SATURATED
SOUNDING FROM LATE TUESDAY AFTERNOON INTO THE OVERNIGHT HOURS BUT
QPF IS 0.00 THERE. HOWEVER...JUST TO THE NORTHWEST OF THAT AREA AT
ALO AND BLR...THESE SAME SOUNDINGS SHOW A SUBSTANTIAL DRY LAYER
THAT WILL NEED TO BE OVERCOME FROM THE SURFACE ON UP TO 700MB. DUE
TO THIS DRY LAYER...AM CONCERNED THAT THE SNOW FROM THIS SYSTEM
MAY NOT MAKE IT VERY FAR TO THE NORTHWEST OF THE MAIN BAND THAT IS
EXPECTED TO BE IN EASTERN IOWA/NORTHERN ILLINOIS. HAVE KEPT THE
CHANCES FOR SNOW GOING FOR THE TIME BEING...BUT THEY MAY HAVE TO
GET TRIMMED BACK IF THE 24.00Z NAM/ECMWF SOUTHEAST TREND HOLDS
FIRM.
.LONG TERM...WEDNESDAY THROUGH SATURDAY
318 AM CST SUN FEB 24 2013
CONFIDENCE IS SOMEWHAT LOW WITH HOW LONG THE LIGHT SNOW MAY HOLD
ON ACROSS THE REGION AS THE TAIL END OF THE SYSTEM MOVES THROUGH.
THERE ARE DIFFERING OPINIONS ON WHERE THE INVERTED SURFACE TROUGH
SETS UP WITH THE 24.00Z ECMWF KEEPING THE AREA DRY THROUGH THE
REST OF THE WEEK WHILE THE 24.00Z GFS/GEM KEEPS SOME LIGHT SNOW IN
THROUGH THURSDAY. KEPT SOME SMALL CHANCES IN THERE FOR NOW INTO
EARLY THURSDAY MORNING...BUT AS MENTIONED FOR TUESDAY...CONFIDENCE
IN HOW FAR NORTHWEST THE SNOW MAKES IT IS PRETTY LOW AT THIS
POINT. DESPITE NORTHERLY FLOW ALOFT AND AT THE SURFACE...THERE IS
NOT MUCH OF A COLD SOURCE OF AN AIR MASS ACROSS CANADA TO PULL ANY
COLD AIR DOWN FROM...SO TEMPERATURES WILL REMAIN AT OR JUST BELOW
NORMAL THROUGH MUCH OF THE NEXT WEEK.
&&
.AVIATION...THROUGH 06Z MONDAY
1139 PM CST SAT FEB 23 2013
BOTH THE NAM AND RAP SHOW THAT THE CLEARING WILL NOT GET INTO KLSE
UNTIL AFTER 23.10Z. IN ADDITION...THE RAP STILL SHOWS 10 TO 15
KNOTS BELOW 1K FEET. AS A RESULT...FEEL THAT THE ODDS OF FREEZING
FOG IS MINUTE. MAIN FORECAST ADJUST WAS TO DELAY THE 2SM BR
ANOTHER 2 HOURS AND START IT AT 24.11Z.
LIKE EARLIER IN THE EVENING...THE BEST CHANCE FOR DENSE FREEZING FOG
WILL BE ACROSS SOUTHEAST MINNESOTA AND NORTHEAST IOWA. KRST WILL
LIKELY DEVELOP DENSE FOG AROUND 24.09Z. THIS FOG WILL THEN DISSIPATE
IN THE 14-16Z TIME FRAME WITH CONDITIONS GRADUALLY IMPROVING TO
MVFR BY MID SUNDAY MORNING AND EVENTUALLY OF VFR BY THE LATE
MORNING HOURS. AS THIS OCCURS..A LAYER OF 10-15K FEET CLOUDS
WILL MOVE INTO THE AREA AND PERSIST INTO SUNDAY EVENING
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
318 AM CST SUN FEB 24 2013
WI...FREEZING FOG ADVISORY UNTIL 9 AM CST THIS MORNING FOR WIZ032>034-
041-042-053>055-061.
MN...FREEZING FOG ADVISORY UNTIL 9 AM CST THIS MORNING FOR MNZ079-
086>088-094>096.
IA...FREEZING FOG ADVISORY UNTIL 9 AM CST THIS MORNING FOR IAZ008>011-
018-019-029-030.
&&
$$
SHORT TERM...HALBACH
LONG TERM...HALBACH
AVIATION...BOYNE
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
1140 PM CST SAT FEB 23 2013
.SHORT TERM...OVERNIGHT
959 PM CST SAT FEB 23 2013
THE CLEARING LINE STOPPED ITS EASTWARD PROGRESS ACROSS SOUTHEAST
MINNESOTA AND NORTHEAST IOWA AROUND 6 PM. BOTH THE RAP AND NAM ARE
IN GOOD AGREEMENT THAT THE CLEARING WILL NOT TAKE PLACE UNTIL THE
SURFACE RIDGE AXIS SLIDES THROUGH THE AREA. THIS WILL NOT OCCUR
UNTIL AFTER 3 AM FOR THE COUNTIES ALONG THE MISSISSIPPI RIVER AND
FOR CENTRAL WISCONSIN UNTIL AFTER 6 AM. IN ADDITION...IF SKIES DID
CLEAR...RAP SOUNDINGS SHOW 10 TO 15 KNOT WINDS IN THE LOWEST 1K
FEET UNTIL 24.11Z. THIS WOULD ONLY LEAVE A COUPLE OF HOURS FOR THE
FREEZING FOG TO FORM. AS A RESULT...NOT OVERLY CONFIDENT THAT THE
WESTERN WISCONSIN WILL SEE ANY FREEZING FOG.
IN SOUTHEAST MINNESOTA AND NORTHEAST IOWA...THERE ARE AREAS OF FOG
ALREADY...THUS THINKING THESE AREAS HAVE A MUCH BETTER CHANCE OF
SEEING THE FREEZING FOG.
.LONG TERM...TUESDAY NIGHT THROUGH SATURDAY
255 PM CST SAT FEB 23 2013
THE LONG TERM FORECAST OVERALL IS FAIRLY QUIET. IN THE UPPER LEVEL
PATTERN...THE ECMWF/GFS/CANADIAN CONTINUE TO FORECAST THAT THE
WEAKENING STORM SYSTEM FROM TUESDAY IS GOING TO GET BOTTLED UP OVER
THE GREAT LAKES REGION...ONLY SLOWLY MOVING TO THE EAST. THERE ARE
TWO REASONS FOR THIS...1. THE SYSTEM IS HAVING TO GET THAT THROUGH
THE RIDGING AHEAD OF IT AND 2. THERE IS ANOTHER FAIRLY POTENT
SHORTWAVE TROUGH ON ITS HEELS COMING ACROSS THE SOUTHERN U.S. THAT
EVENTUALLY GETS ABSORBED. WHAT THIS MEANS FOR OUR AREA IS THAT WE
COULD SEE A GOOD 24 HOURS OR SO OF LIGHT SNOW FROM TUESDAY NIGHT
INTO WEDNESDAY...ASSOCIATED WITH MOISTURE WRAPPING AROUND THE UPPER
LOW. RAISED PRECIPITATION CHANCES SLIGHTLY...BUT FURTHER INCREASES
ARE LIKELY NEEDED. ONCE THE UPPER LOW SHIFTS EAST...THEN HIGH
PRESSURE BUILDS IN FROM THE U.S. AND CANADIAN PLAINS. HOWEVER...THE
HIGH PRESSURE AREA DOES NOT LOOK TO BUILD INTO THE AREA UNTIL
SATURDAY AT THE EARLIEST. A COMBINATION OF UPPER RIDGING BUILDING
OVER THE WESTERN U.S. AND TROUGHING HOLDING IN PLACE OVER THE
EASTERN U.S. LOOKS TO RESULT IN THIS SETUP. THEREFORE...A PROLONGED
PERIOD OF DRY...NORTHERLY FLOW IS EXPECTED. DESPITE THE NORTHERLY
FLOW...THE 850MB TEMPS BOTTOM OUT MAYBE AROUND -10C...THUS
TEMPERATURES SHOULD HANG JUST BELOW NORMAL.
&&
.AVIATION...THROUGH 06Z MONDAY
1139 PM CST SAT FEB 23 2013
BOTH THE NAM AND RAP SHOW THAT THE CLEARING WILL NOT GET INTO KLSE
UNTIL AFTER 23.10Z. IN ADDITION...THE RAP STILL SHOWS 10 TO 15
KNOTS BELOW 1K FEET. AS A RESULT...FEEL THAT THE ODDS OF FREEZING
FOG IS MINUTE. MAIN FORECAST ADJUST WAS TO DELAY THE 2SM BR
ANOTHER 2 HOURS AND START IT AT 24.11Z.
LIKE EARLIER IN THE EVENING...THE BEST CHANCE FOR DENSE FREEZING FOG
WILL BE ACROSS SOUTHEAST MINNESOTA AND NORTHEAST IOWA. KRST WILL
LIKELY DEVELOP DENSE FOG AROUND 24.09Z. THIS FOG WILL THEN DISSIPATE
IN THE 14-16Z TIME FRAME WITH CONDITIONS GRADUALLY IMPROVING TO
MVFR BY MID SUNDAY MORNING AND EVENTUALLY OF VFR BY THE LATE
MORNING HOURS. AS THIS OCCURS..A LAYER OF 10-15K FEET CLOUDS
WILL MOVE INTO THE AREA AND PERSIST INTO SUNDAY EVENING
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
255 PM CST SAT FEB 23 2013
WI...FREEZING FOG ADVISORY FROM 10 PM THIS EVENING TO 9 AM CST SUNDAY
FOR WIZ032>034-041-042-053>055-061.
MN...FREEZING FOG ADVISORY FROM 10 PM THIS EVENING TO 9 AM CST SUNDAY
FOR MNZ079-086>088-094>096.
IA...FREEZING FOG ADVISORY FROM 10 PM THIS EVENING TO 9 AM CST SUNDAY
FOR IAZ008>011-018-019-029-030.
&&
$$
SHORT TERM...BOYNE
LONG TERM...AJ
AVIATION...BOYNE
AREA FORECAST DISCUSSION
NWS DES MOINES IA
1139 PM CST MON FEB 25 2013
.UPDATE...
ADDED 06Z TAF DISCUSSION. ALSO ISSUED SPS TO HIGHLIGHT REDUCED
VSBYS OVER W CENTRAL TO N CENTRAL IA. BRIDGE AND ROAD SURFACE TEMPS
ARE APPROACHING DEWPOINTS AS WELL...SO FELT PATCHY FROST MAY ALSO
FORM ON BRIDGES AND OVERPASSES. COMBINATION OF GRADUALLY INCREASING
WINDS...STRATUS...AND MID/CLOUDS SPREADING NWD WILL KEEP CONDITIONS
FROM DETERIORATE TOO MUCH. SHOULD STAY ABOVE ADVISORY CRITERIA IN
SPACE AND MAGNITUDE.
PREVIOUS UPDATE...NO CHANGES TO HEADLINES OR FORECAST THIS EVENING.
18Z GUIDANCE HAD A POOR HANDLE ON SITUATION WITH MO/AR CONVECTION
STRONGER AND FARTHER EAST THAN ANTICIPATED. THIS LIKELY RESULTING
IN MODELS INCORRECTLY HANDLING THE LATENT HEAT/PV BUDGETS WITH
QUESTIONABLE RESULTS. 18Z NAM WAS DEFINITELY ONE OF THOSE LACKING
AND THE 00Z RUN SEEMS BEHIND BRINGING TROWEL PRECIP INTO KC METRO
AREA RIGHT NOW. SO WITH LITTLE NEW TRUSTED GUIDANCE
AVAILABLE...WILL LEAVE CURRENT FORECAST AND HEADLINES RIDE. SHORTER
TERM 00Z HRRR DOES SEEM TO HAVE A GRASP ON REALITY AND BRINGS PRECIP
INTO SRN IA OVERNIGHT...ANOTHER REASON TO LEAVE THINGS AS IS.
&&
.SHORT TERM /TONIGHT/...
LOW PRESSURE NOW DEEPENING OVER ARKANSAS THIS AFTERNOON. THE
SYSTEM WILL LIFT VERY SLOWLY NORTHEAST OVERNIGHT AND WILL BEGIN
TO INCH INTO FAR SOUTHERN MISSOURI BY 12Z. THE UPPER LEVEL LOW IS
BACK TO THE WEST OVER OKLAHOMA AND TEXAS AND WILL BECOME NEARLY
STACKED WITH THE SFC FEATURE BY 12Z. THE PRESSURE GRADIENT WILL
INCREASE OVER IOWA OVERNIGHT AND WILL INCREASE NORTHERN SURFACE
WINDS ACROSS THE STATE. THE SOURCE REGION FOR THESE WINDS WILL BE
FROM HIGH PRESSURE OVER MINNESOTA AND WISCONSIN WHICH WILL
CONTINUE TO FUNNEL DRIER AIR INTO THE STATE. AS THIS OCCURS...MID
LEVEL THETA-E ADVECTION WILL LIFT NORTH INTO SOUTHERN IOWA. THE
INFILTRATION OF THE DRIER AIR WILL DELAY THE ONSET OF SNOW ACROSS
THAT REGION. THERE IS SOME POTENTIAL FOR SATURATION TO OCCUR OVER
FAR SOUTH CENTRAL TO SOUTHWEST IOWA TO SATURATE TOWARD 06Z.
POTENTIAL FOR UP TO ONE INCH OF SNOW IN THESE AREAS. ELSEWHERE
WILL REMAIN DRY THROUGH THE PERIOD.
AREAS OF FOG LINGERED ACROSS NORTHWEST IOWA THROUGH THE DAY.
POSSIBLE THAT VISIBILITIES WILL LOWER A BIT OVERNIGHT THROUGH
EXPECT THE INCREASING NORTHERLY FLOW OVERNIGHT WILL IMPROVE
CONDITIONS THROUGH THE PERIOD.
.LONG TERM /TUESDAY THROUGH SUNDAY/...
MAIN FORECAST CONCERN IS WITH UPPER LOW STRENGTHENING AS IT MOVES
ACROSS THE CENTRAL/SOUTHERN PLAINS TONIGHT THROUGH WEDNESDAY. MODELS
HAVE TRENDED ON A FURTHER SOUTHEAST TRACK AS SURFACE HIGH REMAINS A
STRONGHOLD OVER THE WESTERN GREAT LAKES DURING THE DAY TUESDAY.
LEANED TOWARD A SREF/GFS BLEND AND THE 12Z ECMWF AS THESE MODELS ARE
IN GOOD AGREEMENT WITH ONE ANOTHER. NAM HAS COMPLETELY SHIFTED THE
LOW TRACK FURTHER SOUTHEAST COMPARED TO PREVIOUS RUNS AND HAD LOW
CONFIDENCE WITH THIS SOLUTIONS DUE TO DISCONTINUITY.
TUESDAY THROUGH WEDNESDAY...NEAR VERTICALLY STACKED LOW WILL TRACK
ACROSS THE OZARKS INTO OHIO VALLEY THROUGHOUT THE DAY TUESDAY AND
TUESDAY NIGHT. A SECONDARY SHORTWAVE QUICKLY MOVES ACROSS NORTHERN
MISSOURI TUESDAY NIGHT INTO WEDNESDAY. BEST FRONTOGENETICAL FORCING
REMAINS JUST ALONG THE IOWA/MISSOURI BY 12Z TO 18Z TUESDAY...THEN
LOOKS TO BE AN ELONGATED PERIOD OF LIGHT TO MODERATE SNOW. MAX OMEGA
WITHIN THE DENDRITIC ZONE MATCHES UP WELL LATE TUESDAY MORNING INTO
THE EARLY AFTERNOON HOURS ACROSS FAR SOUTHEAST IOWA...THEN WEAKENS
BY THE AFTERNOON AND EVENING. SECOND SHORTWAVE WILL BRING
REINFORCEMENT OF LIFT AND MOISTURE AND LOOKS TO PROLONG THE SNOWFALL
INTO EARLY WEDNESDAY. OTHER CONCERN IS WITH STRONG SURFACE WINDS AS
PRESSURE GRADIENT REALLY TIGHTENS THROUGHOUT THE DAY TOMORROW AND
CONTINUES INTO WEDNESDAY MORNING. WINDS AT 925MB ARE ROUGHLY 35KTS
THROUGH MUCH OF THE DAY TUESDAY THEN DECREASING SOMEWHAT TOMORROW
NIGHT INTO WEDNESDAY. SHARP GRADIENT WRT TO SNOW AMOUNTS SETS UP
ACROSS SOUTHEAST IOWA WITH THE DRY AIR ADVECTING IN FROM THE NORTH.
CONFIDENT THOUGH THE SOUTHEAST WILL SEE A 4 TO 6 INCH RANGE
COMBINED WITH THE STRONG WINDS...LEANED TOWARD WINTER STORM
WARNING.
THURSDAY THROUGH SUNDAY...NO MAJOR CHANGES WITH EXTENDED PERIOD AS
HIGH PRESSURE REMAINS IN CONTROL THROUGH THE WEEKEND. A GRADUAL
WARM UP BEGINS BY THE WEEKEND INTO EARLY NEXT WEEK.
&&
.AVIATION...26/06Z
CONDITIONS DETERIORATE FROM VFR SE /KOTM/ TO MVFR CENTRAL SECTIONS
/KDSM/KFOD/KALO/ TO IFR AND LIFR WEST AND N CENTRAL /KMCW/. THESE
RESTRICTIONS ARE DUE TO FOG AND STRATUS AND SHOULD REMAIN FAIRLY
STATIC THROUGH DAYBREAK. HOWEVER LARGE SYSTEM JUST TO OUR SOUTH
WILL EVENTUALLY SPREAD SNOW INTO CENTRAL AND SOUTHERN IOWA WITH SNOW
VSBYS AND CIGS DROPPING CONDITIONS TO IFR VSBYS AND POTENTIALLY CIGS
SOUTH...MAINLY AT KOTM. THIS SHOULD LAST INTO THE EVENING TO VARIED
DEGREES. MODELS ARE STILL NOT HANDLING THIS SYSTEM WELL HOWEVER SO
CONFIDENCE IN TIMING AND NWD EXTENT OF DEGRADED CONDITIONS IS NOT
THE GREATEST.
&&
.DMX WATCHES/WARNINGS/ADVISORIES...
WINTER WEATHER ADVISORY FROM 9 AM TUE TO 6 AM WED
CLARKE-DECATUR-LUCAS-MAHASKA-MARION-MONROE-RINGGOLD-WAPELLO-WAYNE
WINTER STORM WARNING FROM 9 AM TUE TO 6 AM CST WED APPANOOSE-DAVIS
&&
$$
UPDATE/AVIATION...SMALL
SHORT TERM...DONAVON
LONG TERM...PODRAZIK
AREA FORECAST DISCUSSION
NWS WAKEFIELD VA
413 AM EST TUE FEB 26 2013
.SYNOPSIS...
STRONG LOW PRESSURE WILL TRACK FROM THE LOWER TENNESSEE VALLEY TO
THE GREAT LAKES TODAY. A SECONDARY LOW DEVELOPING OVER THE
SOUTHERN APPALACHIANS IS EXPECTED TO PULLING A WARM FRONT UP INTO
THE REGION LATER TODAY...RESULTING IN WIDESPREAD RAINFALL. DRY
WEATHER RETURNS ON WEDNESDAY, WITH GRADUALLY COOLER CONDITIONS
FOR THE LATTER HALF OF THE WEEK.
&&
.NEAR TERM /THROUGH TONIGHT/...
LATEST WATER VAPOR IMAGERY SHOWS STRONG UPPER LOW LOCATED OVER THE
LOWER MISSISSIPPI RVR VALLEY EARLY THIS MORNING. AT THE
SFC...POWERFUL AREA OF SFC LOW PRESSURE CONTINUES TO LIFT NE
ACROSS THE OZARKS/CENTRAL MS VLY, WITH A WELL-DEFINED WARM
CONVEYOR BELT EVIDENT ON IR/WV SAT IMAGERY SPREADING PCPN ACROSS
THE TN AND LOWER OH VLYS. FARTHER SOUTH, A WARM FRONT WAS ANALYZED
ALONG THE GULF COAST...EXTENDING NEWD ALONG THE SE COAST.
SECONDARY LOW PRESSURE WAS BEGINNING TO DEVELOP ACROSS THE GULF
COAST, WITH MSAS 3-HR PRESSURE FALLS ON THE ORDER OF 3-4MB OVER S
MS/GA. FINALLY, TO THE NORTH ~1024MB SFC HIGH PRESSURE HAS
RETREATED INTO THE NORTHEAST US, BUT CONTINUES TO NOSE DOWN THE
EAST COAST THIS MORNING.
INCREASING ISENTROPIC LIFT/SWLY FLOW WILL CONTINUE TO ADVECT
UPPER/MID LEVEL MOISTURE INTO THE REGION OVER THE NEXT FEW HOURS.
REGIONAL RADAR MOSAIC INDICATING PRECIP BREAKING OUT ACROSS
WESTERN CAROLINAS AT THIS HOUR, AND LIKELY NOT TO PUSH INTO FAR SW
CORNER OF AKQ CWA UNTIL AFTER SUNRISE. HAVE AGAIN LOWERED POP FOR
THE NEXT FEW HOURS, WITH HRRR DOING A GOOD JOB THUS FAR IN TIMING
PCPN SHIELD.
AS EXPECTED, DRY ANTECEDENT AIRMASS OVER THE AREA HAS MODIFIED
LITTLE OVER THE PAST FEW HOURS, WITH DEWPOINTS STILL IN THE TEENS
TO LOW 20S ACROSS OUR E VA PIEDMONT COUNTIES. THUS, PRECIP STILL
LKLY SEVERAL HRS OFF. AS PRECIP BREAKS OUT ACROSS THE REGION AFTER
SUNRISE EXPECT A BRIEF PERIOD OF SLEET TO MIX WITH RAIN ACROSS
OUR PIEDMONT COUNTIES. HOWEVER, AS SLUG OF OVERRUNNING MOISTURE
CONTINUES TO DRAW CLOSER AND DRIER AIR CONTINUES TO ERODE, EXPECT
DURATION OF ANY NON-LIQUID PCPN TO BE QUITE BRIEF.
FROM THERE, FORECAST DETAILS HAVE CHANGED VERY LITTLE FROM
PREVIOUS THINKING, WITH A GENERAL MODEL CONSENSUS CONTINUES TO
FAVOR TAKING THE SFC LOW FROM CURRENT POSITION OVER E AR JUST SE
OF KSTL INTO DOWNSTATE IL BY TONIGHT. MEANWHILE, SECONDARY SFC
LOW LOOKS TO SLIDE FROM THE CENTRAL GULF COAST ACROSS THE COASTAL
CAROLINAS. RAIN CHANCES RATCHET UP QUICKLY THIS MORNING INTO THE
AFTN AS WARM FRONT SLIPS NORTH AND VERY MOIST AIRMASS PUSHES INTO
THE AREA. STEADY RAIN LOOKS TO PUSH SW TO NE ACROSS THE AREA FROM
MID MORNING INTO THE EARLY EVENING, WITH RAIN ENDING FROM S TO N
AS WARM FRONT LIFTS NORTH OF THE AREA.
RAINFALL AMOUNTS WILL AVERAGE 0.75" TO 1.50" FOR THIS EVENT. NO
PROBLEMS EXPECTED WITH FLASH FLOOD GUIDANCE, SO NO HEADLINES
ANTICIPATED. SPC HAS AREA OUTLOOKED IN A `GENERAL THUNDER` AREA,
WITH SLIGHT RISK SHUNTED FARTHER SOUTHEAST. THIS JIVES WELL WITH
CURRENT THINKING AS IT APPEARS THAT WARM SECTOR REMAINS ORIENTED
JUST SOUTHEAST OF THE AREA ACROSS FAR SE NC AND POINTS SOUTH. NAM
REMAINS MOST BULLISH WITH MLCAPE. HOWEVER, EVEN THAT SOLUTION
RESULTING IN A MODESTLY UNSTABLE AIRMASS ALOFT, WITH THE BL LKLY
REMAINING STABLE THROUGHOUT.
&&
.SHORT TERM /WEDNESDAY THROUGH THURSDAY/...
WEDNESDAY AND THURSDAY GENERALLY CHARACTERIZED BY DEVELOPING UPPER
TROUGH OVER THE EASTERN CONUS, RESULTING IN GRADUALLY COOLER
CONDITIONS FOR THE MID TO LATE WEEK PERIOD.
SFC LOW AND ASSOCIATED FRONTAL BOUNDARY LIFT NE INTO NEW ENGLAND
EARLY ON WED AS UPPER LOW LINGERS OVER THE OHIO VALLEY/EASTERN
GREAT LAKES. DEEP WSW FLOW IN PLACE WILL BRING A MILD AFTERNOON
WITH HIGH TEMPERATURES IN THE UPR 50S TO MID 60S UNDER A PARTLY
SUNNY SKY. THE UPPER LOW MOVES EAST THROUGH PA ON THURSDAY WITH
THE MAJORITY OF THE MOISTURE/ENERGY WITH THIS SYSTEM STAYING TO
OUR NORTH. HOWEVER...HPC SOLN AS WELL AS THE ECMWF AND ITS
ENSEMBLES DO SUPPORT SHORTWAVE ENERGY PINWHEELING BEHIND THE
SYSTEM AND PIVOTING ACROSS THE REGION ON THURSDAY. PLUMES INDICATE
THIS WOULDN`T BE MUCH, BUT SOME SPOTTY SHRAS CAN`T BE RULED OUT
ACROSS NORTHERN/WESTERN SECTIONS ON THURSDAY. HAVE KEPT SLIGHT
CHC POPS (20%) IN PLACE AS A RESULT. OTHERWISE, EXPECT PARTLY
CLOUDY SKY EARLY GIVING WAY TO AFTN/EVENING CLEARING.
FOR TEMPERATURES, LOWS WED NIGHT IN THE 30S TO ~40. FORECAST HIGH
THU IN THE M/U 40S NORTH TO LOW 50S SOUTH.
&&
.LONG TERM /THURSDAY NIGHT THROUGH MONDAY/...
ANOMALOUS UPR LVL TROUGH TO RMN OVR THE ERN CONUS THROUGH MUCH OF
THE EXTENDED PD. THE TROUGH FCST TO SHIFT E/JUST OFF THE CST BY ERY
NEXT WK. WILL CONT W/ DRY FCST...W/ TEMPS AVGG 5-10F BLO NRML AND
EACH DAY HAVING VRB CLDNS/PCLDY NGTS. HI TEMPS RANGING THROUGH THE
40S. MOST LO TEMPS FM THE M/U20S TO L30S.
&&
.AVIATION /08Z TUESDAY THROUGH SATURDAY/...
A WARM FRONT CURRENTLY DRAPED ALONG THE CAROLINA COAST WILL
GRADUALLY LIFT INTO THE MID ATLANTIC REGION THIS AFTERNOON AS A
COMPLEX LOW PRESSURE SYSTEM APPROACHES THE AREA FROM THE SOUTHWEST
TODAY. OVERRUNNING PRECIPITATION AND LOWER CIGS ASSOCIATED WITH
THE WARM FRONT WILL SPREAD INTO THE MID ATLANTIC REGION FROM THE
SOUTHWEST THIS MORNING AND BEGIN TO IMPACT KRIC...KPHF...KORF...AND
KECG AFTER 26/1600Z. DURING THIS AFTERNOON...RAINFALL WILL BECOME
MODERATE TO HEAVY AT TIMES (LOWERING CIGS TWD 500 FT AGL) AND E-SE
WINDS WILL BECOME BREEZY WITH GUSTS AROUND 25-30 KT. KSBY WILL
BEGIN TO EXPERIENCE SIMILAR CONDITIONS AFTER 26/2000Z.
PRECIPITATION WILL COME TO AN END FROM SOUTHWEST TO NORTHEAST
THROUGH TUESDAY EVENING AS LOW PRESSURE MOVES NORTHEAST AND OUT OF
THE AREA AFTER MIDNIGHT. BREEZY WINDS OVERNIGHT WILL HELP TO SCOUR
OUT LOWER CIGS AND IMPROVE VISIBILITIES ONCE PRECIP COMES TO AN END.
&&
.MARINE...
STARTED SCA NORTH OF PARRAMORE ISLAND WITH SEAS AROUND 5 FT AT
BUOY 09. THIS IS DUE TO SWELL. SCA NOW IN EFFECT OVER THE COASTAL
WATERS S OF VA/NC BORDER WILL EXTEND N TO PARRAMORE ISLAND BY 09Z
WHICH LINES UP WITH WAVEWATCH MODEL (3 HOURS EARLIER THAN PREVIOUS
FCST) . NO CHANGES MADE TO MARINE HEADLINES OVER THE BAY OR INLAND
WATERS.
PREVIOUS DISCUSSION...
WILL HANG ONTO SCA A LTL WHILE LONGER INVOF NE NC OCN WTRS (MAY
ACTUALLY HAVE TO KP IT UP THROUGH THE NGT...AND MERGE W/ CONDS
XPCD TUE INTO WED). OTRW...A LULL IN WINDS...AND SEAS/WAVES AS SFC
HI PRES HAS BECOME CNTRD OVR THE MDATLC STATES. THE CNTR OF THE HI
WILL SLOLY DRIFT NE INTO NEW ENG BY TUE...RESULTING IN INCRSD WIND
SPEEDS FM THE ESE AHD OF NEXT (COMPLEX/OCCLUDED) STORM SYS
APPROACHING FM THE W AND SW. MDL GUID RMNS CONSISTENT HIGHEST PD
FOR WIND SPEEDS I TUE EVE INTO ERY TUE NGT (ROUGHLY 21-23Z/26 TO
05-08Z/27) AHD OF SCNDRY LO PRES TRACKING NE ALG THE CSTL PLAIN.
DIRECTION WOULD BE ESE DURG HIGHEST WIND SPEEDS...THEN A SHIFT TO
THE SW OVRNGT TUE NGT (W/ SPDS LWRG) AS THE LO CONTS MOVING NNE TO
NR THE CNTRL NJ CST BY 12Z/27 (WED MRNG). AFT THAT...PROLONGED PD
OF OFFSHR WINDS... INITIALLY WSW ON WED...THEN WNW FM THU INTO THE
WKND...AND PTNTL FOR XTNDD PD OF SCAS ESP DUE TO LONG PD OF LO LVL
CAA AND SPDS AOA 20-25 KT AT TIMES.
HOISTING SCAS FOR ALL AREAS EITHER FM LT TNGT/TUE MRNG OR TUE
AFTN...AND LASTING INTO TUE NGT (ON THE OCN...INTO ERY WED).
ALSO...DUE TO PTNTL 35 KT GUSTS...GALE WARNING RAISED ON THE NRN 3
OCN ZONES (22Z/26-06Z/27).
&&
.AKQ WATCHES/WARNINGS/ADVISORIES...
MD...NONE.
NC...NONE.
VA...NONE.
MARINE...SMALL CRAFT ADVISORY FROM NOON TODAY TO 1 AM EST WEDNESDAY FOR
ANZ630-631-633-635>638.
SMALL CRAFT ADVISORY FROM 6 AM THIS MORNING TO 5 AM EST
WEDNESDAY FOR ANZ632-634.
SMALL CRAFT ADVISORY UNTIL 5 PM EST THIS AFTERNOON FOR ANZ654.
GALE WARNING FROM 5 PM THIS AFTERNOON TO 1 AM EST WEDNESDAY
FOR ANZ650-652-654.
SMALL CRAFT ADVISORY UNTIL 10 AM EST WEDNESDAY FOR ANZ656.
SMALL CRAFT ADVISORY UNTIL 5 PM EST THIS AFTERNOON FOR ANZ650-
652.
SMALL CRAFT ADVISORY UNTIL 10 AM EST WEDNESDAY FOR ANZ658.
&&
$$
SYNOPSIS...MAM
NEAR TERM...JDM/MAM
SHORT TERM...MAM
LONG TERM...ALB
AVIATION...BMD
MARINE...BMD
AREA FORECAST DISCUSSION
NWS BALTIMORE MD/WASHINGTON DC
325 AM EST TUE FEB 26 2013
.SYNOPSIS...
A COMPLEX LOW PRESSURE SYSTEM WILL ARRIVE LATER THIS MORNING...
MOVING ACROSS THE REGION OVER THE COURSE OF THE DAY. A SURFACE LOW
WILL SLIDE OVER THE AREA LATE TONIGHT...BRINGING MORE RAIN AND GUSTY
WINDS BEFORE MOVING OFF TO THE NORTHEAST WEDNESDAY MORNING. A
TROUGH OF LOW PRESSURE WILL FOLLOW AND WILL PASS SLOWLY EAST
ACROSS THE REGION WEDNESDAY NIGHT AND THURSDAY. FOR THE
WEEKEND...LOW PRESSURE WILL REMAIN OFF THE COAST WHILE HIGH
PRESSURE SLOWLY PUSHES IN FROM THE CENTRAL STATES.
&&
.NEAR TERM /UNTIL 6 AM THIS MORNING/...
CLOUDS WILL CONTINUE TO THICKEN AND LOWER AS LOW PRESSURE BEGINS
TO MOVE IN.
&&
.SHORT TERM /6 AM THIS MORNING THROUGH 6 PM WEDNESDAY/...
A LARGE AND STILL INTENSE LOW PRESSURE SYSTEM NOW MAKING ITS WAY
UP THE ERN SEABOARD. THE PARENT UPPER LOW DRIVING THE STORM SYSTEM
IS STILL BACK ACROSS THE CNTRL PLAINS...SPREADING HEAVY SNOW AND
BLIZZARD CONDITIONS FROM OK TO IL. THE OTHER SIDE OF THE STORM
LIES ACROSS THE DEEP SOUTH...SPREADING PLENTY OF PRECIP ACROSS THE
SRN STATES AND THIS BATCH WILL EVENTUALLY MOVE ACROSS OUR REGION.
WHILE THE PLAINS UPPER LOW CONTINUES TO SLOWLY DRIFT EWD...THE
LARGE GULF MOISTURE FETCH WILL BE DRIVEN UP THE ERN SEABOARD OVER
THE COURSE OF TODAY-TONIGHT.
THE MAIN ISSUE FOR ABOUT THE WRN HALF OF THE CWA IS THE SUB-FREEZING
OVERNIGHT TEMPS AND SOME COLD-AIR LOCKED INTO AREA MTN VLYS AS THE
PRECIP ARRIVES IN JUST A FEW HRS. CLEAR SKIES OVER THE PAST SEVERAL
HRS ALLOWED AREA TEMPS TO PLUMMET AFTER A RELATIVELY WARM AFTN. THE
CIRRUS DEBRIS FROM THE INCOMING WAVE OF PRECIP HAS ALREADY OVERTAKEN
MUCH OF THE AREA...WHICH WILL BASICALLY HOLD THESE TEMPS IN
PLACE...PREVENTING THEM FROM DROPPING MUCH FURTHER BUT ALSO KEEPING
THEM NEARLY STEADY IN THE 25-30 DEG RANGE AS PRECIP ARRIVES. ALSO
COMING IN FAST WILL BE A POTENT LOW LEVEL JET MAX...CARRYING WARMER
TEMPS RIDING OVER THE BOUNDARY LAYER. FALLING PRECIP WILL START OUT
AS A MIX OF RAIN...SLEET AND SOME SNOW ALONG THE LEADING EDGE OVER
MUCH OF THE AREA - BUT MAINLY WEST OF THE I-95 CORRIDOR.
PRECIP IS QUICKLY APPROACHING AND WILL ARRIVE OVER THE SWRN COUNTIES
OF THE CWA TOWARD DAWN...QUICKLY TRUDGING UP THE PIEDMONT/SHEN VLY
THRU THE REST OF THE MRNG HRS. NEAR-TERM GUIDANCE LIKE THE HRRR AND
VARIOUS LOCAL WRF GUIDANCE HAVE THE CWA COVERED IN PRECIP BY EARLY
AFTN...INCLUDING THE DC/BALT AREAS - BUT ALL RAIN BY THAT TIME FOR
THE I-95 CORRIDOR.
THE MAIN HAZARDS IN EFFECT FOR THE AREA ARE THE WINTRY PRECIP
POTENTIAL FOR AREAS ALONG AND W OF THE BLUE RIDGE AND THE HEIGHTENED
FLOODING POTENTIAL FOR MUCH OF THE METRO AREAS W/ THE LOWER FFG.
WHILE OTHER AREAS OF THE CWA COULD SEE HIGHER STORM-TOTAL RAINFALL
AMOUNTS...FFG IS MUCH LOWER ACROSS THE METROPOLITAN REGION AND WE`RE
STILL IN THE TIME OF YEAR WHERE THERE IS MORE RUNOFF THAN MOISTURE
SOAKED INTO THE SOIL. THE HIGHEST RAINFALL TOTALS FROM TODAY ARE
EXPECTED TO BE MAINLY ON THE LEE SIDE OF THE BLUE RIDGE. PERIODS OF
UPSLOPE AND TERRAIN INTERACTION RAINS BETWEEN THE RIDGE AND THE HWY
29 CORRIDOR COULD AMOUNT TO ACCUMULATED RAINFALL BETWEEN 1-1.5
INCHES W/ LOCALLY HIGHER AMOUNTS. MOST GUIDANCE MEMBERS ARE IN-SYNC
W/ AREA AVERAGES NEAR AN INCH BY LATE TONIGHT WHEN THE SYSTEM MOVES
AWAY FROM THE REGION.
CONCERNS FOR GOOD AMOUNTS OF ICE ACCRETION REMAIN ACROSS THE WRN
TIER OF THE CWA ALONG THE HIGHER TERRAIN AND TO A LESSER
EXTENT...NEARBY VLYS. AS W/ MOST ICING/COLD AIR DAMMING
EVENTS...TODAY WILL SEE A MIX OF RISING AND LOWERING LEVELS OF
ABOVE-FREEZING AIR IN THE BOUNDARY LAYER INTERACTING W/ THE APLCN
RIDGELINES. ACROSS THE SHEN VLY...THE BLUE RIDGE AND SURROUNDING
FOOTHILL REGIONS...BRIEF PERIODS OF FREEZING RAIN ARE EXPECTED AT
PRECIP ONSET AND TOWARD THE MID MRNG HRS. AS THE DAY PROGRESSES AND
TEMPS RISE SLOWLY OUT OF THE FROZEN REALM...MORE OF THE AREA WILL
RECEIVE ALL-RAIN AN HELP TO MELT ANY ICE THAT HAS FORMED.
&&
.LONG TERM /WEDNESDAY THROUGH MONDAY/...
WEDNESDAY MORNING THE SECONDARY LOW WILL BE PULLING TO THE N OF THE
MASON DIXON LINE...LEAVING JUST THE LARGE 500MB CUTOFF OVER THE
MIDWEST. IN BETWEEN THE TWO...TEMPS ON SW FLOW WILL WARM INTO THE
50S AND LOWS 60S ACROSS THE FORECAST AREA ON WED.
LATER...THE CENTER OF THAT 500 MB LOW WILL SLIDE SLOWLY EAST OVER
SOUTHERN PA AND NORTHERN MD WED NIGHT INTO THURSDAY. WITH THE STEEP
LAPSE RATES ASSOC WITH THAT...THERE WILL BE SCATTERED SHOWERS AROUND
WED NIGHT INTO THU...LIKELY WILL BE A MIX OF RAIN AND SNOW SHOWERS
DEPENDING ON THE TIME OF DAY AND ELEVATION OF REPORT. PRECIP AMOUNTS
WILL BE LIGHT...AND WITH TEMPS STAYING ABOVE FREEZING THRU THE
TIME...IMPACT OF ANY SNOW SHOWERS SHOULD BE MINIMIZED.
AFTER THAT FOR THE END OF THE WEEK INTO EARLY NEXT WEEK...ANY PRECIP
SHOULD BE LIMITED TO MOUNTAIN SNOW SHOWERS. THE OPERATIONAL GFS HAS
A STRONGER UPPER LOW FORECAST OVER THE AREA ON SUNDAY...BUT IS
DISCOUNTED FOR NOW. AFTER WED...TEMPS WILL BE NEAR OR BELOW NORMAL
INTO EARLY NEXT WEEK.
&&
.AVIATION /08Z TUESDAY THROUGH SATURDAY/...
THE PIECE OF THE MUCH LARGER STORM SYSTEM THAT WILL MOVE ACROSS OUR
AREA WILL MAINLY BE A SEVERAL-HR PERIOD OF LIGHT-MODERATE RAINS.
GUSTY WINDS WILL BEGIN TO SPREAD ACROSS THE AREA TOWARD LATE
EVE...AS THE SFC LOW DRIFTS ACROSS THE REGION BUT MAINLY LIGHT WINDS
THRU THE REMAINDER OF THE MRNG. LIGHT PRECIP THAT STARTS AFTER DAWN
WILL BE A WINTRY MIX TOWARD THE KCHO REGION...AND TO A LESSER EXTENT
AS IT ARRIVES OVER THE DC/BALT AREA AIRPORTS. CIGS AND VSBYS WILL
LIKELY DROP TOWARD IFR LATER THIS AFTN/EVE AS THE HEAVIER RAIN
SHOWERS MOVE ACROSS THE REGION. AS PRECIP LETS-UP...SOLID IFR
CONDITIONS ARE EXPECTED TO LINGER INTO THE OVERNIGHT HRS AT LEAST
INTO THE PREDAWN HRS WED.
CONDITIONS WILL GRADUALLY IMPROVE BEGINNING WEDNESDAY MORNING AS LOW
PRESSURE SLOWLY PULLS AWAY TO THE NORTH AND EAST. SCATTERED RAIN AND
SNOW SHOWERS WILL BRING LOCALLY LOWER VSBYS AND CIGS WITH SHOWERS
WED NIGHT THRU THU. AREAS OF FOG COULD DEVELOP DURING THE OVERNIGHT
PERIODS WITH MOIST GROUND IN PLACE.
&&
.MARINE...
QUIET ON THE WATERS BUT ONLY FOR A FEW MORE HRS. AN INTENSE STORM
SYSTEM AFFECTING AREAS FROM THE PLAINS TO THE SOUTHEAST WILL SWEEP
ACROSS THE REGION TODAY. WINDS WILL PICK UP OUT OF THE EAST DURING
THE MID-LATE MRNG HRS. A SFC LOW COMING OUT OF THE CAROLINAS WILL
SLIDE UP TOWARD THE AREA LATER TODAY...BRINGING WIDESPREAD RAIN AND
GUSTY WINDS TO THE MARINE AREAS. NEAR-GALE GUSTS WILL BE POSSIBLE
LATE TONIGHT AS THE LOW MOVES OVER THE NRN CHESAPEAKE BAY. SMALL
CRAFT CONDITIONS WILL ARRIVE EARLIER IN THE DAY...BUT ALSO END
QUICKLY DURING THE OVERNIGHT HRS.
BREEZY CONDITIONS COULD DEVELOP ON THE BACKSIDE OF THE LOW THU AND
FRI. A SMALL CRAFT ADVISORY MAY BE NEEDED. WINDS ARE EXPECTED TO
REMAIN BELOW ADVISORY LEVELS FRIDAY NIGHT AND SATURDAY.
&&
.TIDES/COASTAL FLOODING...
LOPRES MVG THRU THE OHVLY TUE WL PROMOTE INCRSG E/SELY FLOW.
THEREFORE...WUD XPCT POS WATER ANOMOLIES TO INCR DURING THE DAY. A
SECONDARY AREA OF LOPRES WIL CROSS THE WATERS WED MRNG. HOWEVER...
WNDS DONT TURN W/NWLY TIL LATE DAY THU. THAT WUD SUGGEST THAT
WHATEVER EXCESS WATER IS DRIVEN INTO THE ESTUARY MAY BE THERE FOR A
WHILE.
IN SPITE OF A FULL MOON...ETSS MDL GDNC YIELDS WATER LVLS THAT
WOULDNT YIELD ADVY LVL WATER HGTS. THE 1ST TIDE OF CONSEQUENCE WOULD
BE THE WED MRNG TIDE CYCLE. THE TWO TIDES ASTRONOMICALLY ARE
PRACTICALLY THE SAME...SO THE SEMI-DIURNAL CYCLE WONT FACTOR
CONSIDERABLY THIS TIME.
ESTOFS...CBOFS AND HEC-RAS GDNC SOLNS DO RESULT IN MINOR FLOODING...
EITHER BEGINNING WED MRNG /CBOFS/ OR TUE NGT /ESTOFS FOR THE WRN
SHORE OF THE CHSPK BAY AS WELL AS HEC-RAS AT WASD2/. BASED ON THE
PTTN...THESE RESULTS SEEM MORE REALISTIC. SINCE WE/RE AT LEAST 24
HRS OUT...WL CONT HAZARDOUS WEATHER OUTLOOK WORDING AT THIS TIME.
WOULD BE MINDFUL OF BOTH TIDE CYCLES FOR STARTERS.
&&
.LWX WATCHES/WARNINGS/ADVISORIES...
DC...FLOOD WATCH FROM 3 PM EST THIS AFTERNOON THROUGH THIS EVENING
FOR DCZ001.
MD...WINTER STORM WARNING FROM 7 AM THIS MORNING TO MIDNIGHT EST
TONIGHT FOR MDZ501.
FLOOD WATCH FROM 3 PM EST THIS AFTERNOON THROUGH THIS EVENING
FOR MDZ004>006-009>011-013-014.
WINTER WEATHER ADVISORY FROM 7 AM THIS MORNING TO 6 PM EST
THIS EVENING FOR MDZ003-502.
VA...WINTER STORM WARNING FROM 7 AM THIS MORNING TO MIDNIGHT EST
TONIGHT FOR VAZ503-504.
FLOOD WATCH FROM 3 PM EST THIS AFTERNOON THROUGH THIS EVENING
FOR VAZ042-053-054-501.
WINTER WEATHER ADVISORY FROM 7 AM THIS MORNING TO 6 PM EST
THIS EVENING FOR VAZ025>031-036>040.
WV...WINTER STORM WARNING FROM 7 AM THIS MORNING TO MIDNIGHT EST
TONIGHT FOR WVZ501-503-505-506.
WINTER WEATHER ADVISORY FROM 7 AM THIS MORNING TO 6 PM EST
THIS EVENING FOR WVZ050>053-055-502-504.
MARINE...SMALL CRAFT ADVISORY FROM 11 AM THIS MORNING TO 6 AM EST
WEDNESDAY FOR ANZ530>543.
&&
$$
SYNOPSIS...CAS/GMS
NEAR TERM...CAS
SHORT TERM...GMS
LONG TERM...CAS
AVIATION...CAS/GMS
MARINE...CAS/GMS
TIDES/COASTAL FLOODING...GMS/HTS
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
358 AM EST TUE FEB 26 2013
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 357 AM EST TUE FEB 26 2013
00Z RAOBS/LATEST WV IMAGERY AND RUC ANALYSIS SHOW SPLIT FLOW PATTERN
ACRS NAMERICA...WITH THE UPR GRT LKS UNDER A POLAR JET STREAM WELL S
OF ARCTIC BRANCH IN CENTRL CANADA THAT HAS CONFINED THE BITTERLY
COLD ARCTIC AIR TO FAR NRN CANADA. AN ACTIVE SUBTROPICAL BRANCH
DOMINATES THE S HALF OF THE CONUS...WITH A POTENT DISTURBANCE MOVING
INTO THE LOWER-MID MS RIVER VALLEY. A DISTURBANCE WITHIN THE POLAR
BRANCH IS MOVING ACRS UPR MI EARLY THIS MRNG...BUT LIMITED MSTR
DEPTH PER 00Z GRB/APX RAOBS AND GENERAL LARGER SCALE ACYC FLOW
RELATED TO RDG AXIS EXTENDING WWD FM HI CENTER IN SE CANADA HAS
RESTRICTED ANY IMPACT TO AN AREA OF SC. THE BACK EDGE OF THIS CLD
AREA IS JUST INLAND FM THE W SHORE OF UPR MI CLOSER TO INCOMING AREA
OF DRY AIR DEPICTED ON THE 00Z INL/MPX RAOBS AND WHICH IS UNDER
DNVA/LARGE SCALE QVECTOR DVGC BEHIND THE SHRTWV. SKIES OVER FAR NW
WI/WRN LK SUP AND THE MN ARROWHEAD OF MOCLR...WHICH HAS ALLOWED SOME
FOG TO FORM WITH LGT WINDS. HI CLDS ON THE NRN EDGE OF THE
SUBTROPICAL BRANCH DISTURBANCE TO THE S ARE SPREADING SLOWLY NWD
THRU WI.
MAIN FCST CONCERNS TODAY ARE CLD TRENDS/IMPACT ON TEMPS. FOCUS FOR
TNGT SHIFTS TO WHETHER ANY PCPN ASSOCIATED WITH SRN BRANCH
DISTURBANCE WL IMPACT THE SRN CWA.
TODAY...POLAR BRANCH UPR RDG/DNVA/LARGE SCALE QVECTOR DVGC WL
DOMINATE UPR MI TODAY. AS THE SUBTROPICAL BRANCH SFC LO MOVES INTO
THE LOWER OH RIVER VALLEY BY 00Z WED...THE PRES GRADIENT WL TIGHTEN
OVER UPR MI TO THE WSW OF HI CENTERED IN SE CANADA...WITH AN INCRSG
ENE FLOW. ALTHOUGH THE LARGER SCALE NEGATIVE DYNAMICS WOULD INDICATE
A SLOW BREAKUP OF THE SC DOMINATAING MUCH OF THE CWA NOW...THIS LO
CLD IS WIDESPREAD TO THE E OF UPR MI THIS MRNG...THE SOURCE AIRMASS
FOR THE DVLPG E WIND. ON THE OTHER HAND...THE DIFFLUENT NATURE OF
THE LLVL FLOW AS WELL AS STRONG SUBSIDENCE FCST AT H925 SHOULD TEND
TO BREAK UP THE LO CLD. RECENT TRENDS SHOWN ON STLT IMAGERY/SFC OBS
CONFIRM THIS EXPECTATION. DIURNAL HEATING WITH INCRSG LATE FEB SUN
ANGLE WL ALSO TEND TO DISSIPATE THE SC OVER THE LAKES AS H85 TEMPS
ARE FCST TO BE ABOUT -4C...A TYPICAL EARLY SPRING SCENARIO. IN THIS
SCENARIO...SOME DIURNAL CU/SC WOULD TEND TO FORM OVER THE INTERIOR
FOLLOWING INITIAL CLRG. THE COVERAGE OF THIS CLD SHOULD BE LIMITED
BY THE RATHER LO INVRN BASE SHOWN ON NAM/GFS FCST SDNGS. MAINTAINED
OVERALL FLAVOR OF GOING FCST SHOWING A TERND FOR DECREASING CLDS
INTO THIS AFTN...WITH A BIT MORE CLD COVER OVER THE INTERIOR...
ESPECIALLY IN USPLOPE AREAS. MIXING TO H875 ON FCST SDNGS YIELDS HI
TEMPS CLOSE TO 40...MOST LIKELY IN AREAS OVER THE W THAT SEE MORE
SUNSHINE AND DOWNSLOPE IN LLVL ENE FLOW AWAY FM THE COOLING
INFLUENCE OF THE LKS. GOING FCST NEEDS ONLY MINOR ADJUSTMENTS.
TNGT...SUBTROPICAL BRANCH LO IS PROGGED TO MOVE NE INTO OH BY 12Z
WED. THE BULK OF THE NUMERICAL GUIDANCE SHOWS LGT QPF ON THE NW
FLANK OF THIS LO PRES BRUSHING JUST THE SE COUNTIES WITH SOME LGT
PCPN TOWARD 12Z WED...CONSISTENT WITH THE PASSAGE OF THE DEEP LYR
QVECTOR THRU LWR MI. DESPITE CYC NATURE OF THE INCRSG LLVL NE
FLOW...H85 TEMPS NO LOWER THAN ABOUT -5C AS WELL AS FCST DRY H85-7
LYR INDICATE THERE WL BE NO LK EFFECT/ENHANCED PCPN EVEN IF MORE SC
DVLPS IN THE UPSLOPE AREAS. OPTED TO RETAIN GOING SCHC POPS ONLY
CLOSE TO LK MI/BAY OF GREEN BAY.
.LONG TERM...(WEDNESDAY THROUGH MONDAY)
ISSUED AT 357 AM EST TUE FEB 26 2013
NOT MUCH IN THE WAY OF PRECIPITATION EXPECTED THROUGH THIS LONG TERM
PERIOD...WITH MARCH LIKELY COMING IN LIKE A LAMB /AS NOTED ON THE
PREVIOUS DISCUSSION/.
BY WEDNESDAY THE 500MB LOW WILL BE THE CLOSEST IT WILL GET TO THE
CWA...TRACKING FROM OHIO TO NE PENNSYLVANIA...SQUEEZING THE RIDGE
NORTH INTO ONTARIO. EXPECT NE FLOW AT THE SFC AND ALOFT WEDNESDAY.
THE 25/12Z CONTINUES TO SHOW A SOUTHERLY TREND TO THE TRACK...WITH A
DOUBLE BARREL LOW SPLITTING THE APPALACHIANS MERGING ACROSS THE NEW
ENGLAND STATES WEDNESDAY NIGHT. A MEER 24 HOURS AGO THE NAM SOLUTION
WAS FOR THE SURFACE LOW TO SWING ACROSS CENTRAL LOWER MICHIGAN...NOW
IT LOOKS TO BE MORE IN LINE IF NOT SLIGHTLY SLOWER THAN THE
ECMWF/GFS ON WEDNESDAY.
STRONG HIGH PRESSURE STRETCHING ACROSS NORTH CENTRAL CANADA ON
TUESDAY WILL PUSH INTO HUDSON BAY AND MANITOBA/ONTARIO
WEDNESDAY/WEDNESDAY NIGHT...WITH THE RIDGE EDGING ACROSS LAKE
SUPERIOR THURSDAY NIGHT THROUGH AT LEAST SUNDAY MORNING. WE STILL
EXPECT SOME BREEZY CONDITIONS NEAR THE LAKE SUPERIOR SHORELINE
WEDNESDAY THROUGH THURSDAY /PUSHING ACROSS MUCH OF CENTRAL UPPER
MICHIGAN DURING THE DAY THURSDAY/. WINDS WILL SLOWLY DIMINISH AS THE
LOW CONTINUES TO EXIT EAST AND THE SURFACE HIGH PUSHES OVERHEAD.
AS FOR THE CHANCE OF PRECIPITATION THROUGH THE PERIOD...IT IS PRETTY
MINIMAL. THE SYNOPTIC SNOW WILL ONLY CLIP AREAS NEAR LAKE MICHIGAN
WEDNESDAY INTO WEDNESDAY EVENING. EVEN WITH THE FAVORABLE UPSLOPE
WINDS OFF LAKE SUPERIOR...TEMPERATURES AT AND ABOVE THE SURFACE WILL
BE MARGINAL TO SUPPORT ANY ACCUMULATING SNOW SHOWERS.
COLDER AIR WILL FINALLY COME IN FOR THE END OF THE WORK WEEK...WITH
850MB TEMPERATURES FALLING TO AROUND -11C FRIDAY AFTERNOON...AND -12
TO -14C FRIDAY NIGHT THROUGH AT LEAST SUNDAY /WITH N-NE WINDS
CONTINUING THROUGH SATURDAY/.
THE 25/12Z ECMWF KEEPS THE RIDGE IN PLACE THROUGH TUESDAY...BECOMING
OUT OF PHASE WITH THE 25/18Z GFS BY MONDAY NIGHT /STRONG 1044MB HIGH
OVER NORTHERN MANITOBA AND ONTARIO...COMPARED TO THE 1005MB LOW
ACROSS ONTARIO/. WHILE THE 26/00Z GFS DID COME IT SLIGHTLY BETTER
AGREEMENT...IT JUST CAN NOT BEAT THE RUN TO RUN CONSISTENCY BEING
SHOWN BY THE ECMWF. CUT BACK THE SLIGHT CHANCE POPS GIVEN WITH A
CONSENSUS OF THE MODELS FOR DAY 6/MONDAY TO RIGHT ALONG THE
WISCONSIN BORDER...MINIMIZING THE INFLUENCE OF THE 26/00Z GFS RUN ON
THE POPS.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z TUESDAY NIGHT)
ISSUED AT 1224 AM EST TUE FEB 26 2013
MVFR CIGS AT KIWD AND KCMX SHOULD GIVE WAY TO SCT CLOUDS OVERNIGHT
WITH POSSIBLE DEVELOPMENT OF FOG AND MVFR TO IFR VSBY. KSAW SHOULD
STAY UNDER MVFR CLOUD DECK LONGER OVERNIGHT SO EVEN IF THERE IS SOME
PARTIAL CLEARING LATE TONIGHT...FOG SHOULDN`T BE THAT THICK. ONLY
EXPECT MVFR VSBY REDUCTION AT KSAW. EXPECT IMPROVING CONDITIONS ON
TUESDAY WITH A RETURN TO VFR CONDITIONS BY LATE MORNING/EARLY
AFTERNOON.
&&
.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 357 AM EST TUE FEB 26 2013
A RIDGE OF HIGH PRESSURE ACROSS LAKE SUPERIOR WILL PUSH NORTHWARD
TODAY...IN ADVANCE OF WEAKENING LOW PRESSURE SLIDING FROM SOUTHERN
MISSOURI THIS MORNING TO FAR SOUTHEASTERN LOWER MICHIGAN AND OHIO
WEDNESDAY MORNING...AND EXITING ACROSS NEW YORK WEDNESDAY NIGHT. AS
A RESULT...EXPECT A TROUGH OVER LAKE SUPERIOR WITH STEADY N-NE WINDS
FROM MID AFTERNOON THROUGH THE REST OF THE WORK WEEK. THE STRONGEST
WINDS...WITH A FEW GUSTS NEARING 35KTS CAN BE EXPECTED WEDNESDAY
INTO THURSDAY AS LAKE SUPERIOR BECOMES PINNED BETWEEN THE LOW
PRESSURE SYSTEM TO OUR SOUTHEAST AND STRONG HIGH PRESSURE EDGING IN
FROM THE NORTHWEST. GIVEN THE STRONGER WINDS AND COOLER AIR SLIDING
IN...FREEZING SPRAY WILL BE POSSIBLE. HIGH PRESSURE WILL WIN OUT
FRIDAY...WITH A RIDGE RESIDING ACROSS LAKE SUPERIOR THROUGH AT LEAST
SATURDAY NIGHT.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...KC
LONG TERM...KF
AVIATION...VOSS
MARINE...KF
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
258 AM EST TUE FEB 26 2013
.SHORT TERM...(THIS EVENING THROUGH TUESDAY)
ISSUED AT 413 PM EST MON FEB 25 2013
WATER VAPOR IMAGERY AND RUC ANALYSIS SHOW A SPLIT FLOW PATTERN
ACROSS NAMERICA. IN THE SRN STREAM...A WELL-DEFINED MID LEVEL LOW
WAS OVER N TX. IN THE NRN STREAM...A SHORTWAVE TROF EXTENDS FROM
HUDSON BAY TO THE UPPER MISSISSIPPI VALLEY. SOME FLURRIES HAVE BEEN
NOTED IN WI TODAY IN AN AREA OF WEAK ISENTROPIC ASCENT. SOME OF
THOSE FLURRIES MAY HAVE SLIPPED INTO SCTNRL UPPER MI THIS AFTN
ALTHOUGH NO REPORTS HAVE BEEN NOTED. OTHERWISE...MOSTLY CLOUDY SKIES
HAVE BEEN THE RULE TODAY...THOUGH THERE WAS A PERIOD OF MOSTLY SUNNY
SKIES FOR A TIME EARLIER OVER THE FAR W AND NW.
ALTHOUGH THE SHORT TERM PORTION OF THE FCST WILL FEATURE TRANQUIL
WEATHER...CLOUDS AND TEMPS WILL OFFER SOME CHALLENGING ASPECTS TO
THE FCST. UNDER WEAK ISENTROPIC ASCENT...WILL MAINTAIN A MENTION OF
A FEW FLURRIES INTO THE EVENING HRS OVER THE SRN PORTION OF THE FCST
AREA. CLOUD FCST IS NOT CERTAIN AT ALL AND THAT OPENS THE DOOR TO
BIG TEMP BUST POTENTIAL TONIGHT. UNDER LIGHT SW FLOW INTO THE
EVENING...MULTI-LAYERED CLOUDS TO THE SW SHOULD AFFECT MUCH OF THE
FCST AREA. OVERNIGHT...LOW-LEVEL WIND FIELDS BECOME VERY LIGHT WITH
A TREND TO LIGHT EASTERLY LATE WHICH SUGGESTS LITTLE ADVECTION OF
DRIER AIR. THUS...IT WOULD SEEM THAT MUCH OF THE AREA WILL SEE
MOSTLY CLOUDY SKIES TONIGHT. HOWEVER...THE PROXIMITY OF CLEAR SKIES
JUST TO THE W SUGGESTS THE WRN FCST AREA MAY HAVE THE BEST SHOT OF
SEEING A PERIOD OF PARTLY CLOUDY AND POSSIBLY CLEAR SKIES TONIGHT.
ALL IN ALL...THERE IS VERY LOW CONFIDENCE ON SKY CONDITION THRU THE
NIGHT. WITH LIGHT/CALM WINDS AT THE SFC...TEMPS WILL FALL
SIGNIFICANTLY IN SOME AREAS IF SKIES BECOME CLEAR/PARTLY CLOUDY FOR
A TIME. THIS COULD ALSO LEAD TO SOME FOG DEVELOPMENT. AT THIS
POINT...WILL PLAY IT CONSERVATIVE UTILIZING A CONSENSUS APPROACH TO
TEMPS...BUT WILL GO WITH LOWEST MIN TEMPS OVER THE W (MID TEENS)
WHERE IT APPEARS THERE IS A BETTER SHOT OF SEEING LESS CLOUDS FOR AT
LEAST A PORTION OF THE NIGHT. COULD EASILY SEE TEMPS FALL INTO THE
SINGLE DIGITS IF ANY LOCATIONS END UP CLEAR FOR A FEW HRS.
E TO NE WINDS WILL DEVELOP TUE AS UPPER MI FALLS INTO THE NRN
PERIPHERY OF THE CIRCULATION AROUND SRN STREAM LOW. WINDS WILL BE
STRONGEST IN THE MENOMINEE AREA AS A STIFF NE WIND WILL BE THE RULE
IN THE AFTN DUE TO COASTAL CONVERGENCE/FUNNELING DOWN THE BAY.
STRATOCU SHOULD TEND TO BREAK UP AS MODELS SUGGEST SOME DRYING...
BUT THE LWR CLOUDS WILL PROBABLY HANG ON LONGEST WHERE EASTERLY
WINDS UPSLOPE. WHERE LOW CLOUDS SCATTER OUT OR CLEAR...THERE SHOULD
BE A FAIR AMOUNT OF SUNSHINE THRU ONLY SOME HIGH CLOUDS. EXPECT MAX
TEMPS IN THE 30S...COOLEST (LOW 30S) AT LOCATIONS WHERE WINDS ARE
OFF THE LAKES AND IN THE UPSLOPE AREAS. TEMPS COULD RISE TO NEAR 40
IN LOCATIONS THAT SEE DOWNSLOPING WITH EASTERLY WINDS.
.LONG TERM...(WEDNESDAY THROUGH MONDAY)
ISSUED AT 258 AM EST TUE FEB 26 2013
NOT MUCH IN THE WAY OF PRECIPITATION EXPECTED THROUGH THIS LONG TERM
PERIOD...WITH MARCH LIKELY COMING IN LIKE A LAMB /AS NOTED ON THE
PREVIOUS DISCUSSION/.
BY WEDNESDAY THE 500MB LOW WILL BE THE CLOSEST IT WILL GET TO THE
CWA...TRACKING FROM OHIO TO NE PENNSYLVANIA...SQUEEZING THE RIDGE
NORTH INTO ONTARIO. EXPECT NE FLOW AT THE SFC AND ALOFT WEDNESDAY.
THE 25/12Z CONTINUES TO SHOW A SOUTHERLY TREND TO THE TRACK...WITH A
DOUBLE BARREL LOW SPLITTING THE APPALACHIANS MERGING ACROSS THE NEW
ENGLAND STATES WEDNESDAY NIGHT. A MEER 24 HOURS AGO THE NAM SOLUTION
WAS FOR THE SURFACE LOW TO SWING ACROSS CENTRAL LOWER MICHIGAN...NOW
IT LOOKS TO BE MORE IN LINE IF NOT SLIGHTLY SLOWER THAN THE
ECMWF/GFS ON WEDNESDAY.
STRONG HIGH PRESSURE STRETCHING ACROSS NORTH CENTRAL CANADA ON
TUESDAY WILL PUSH INTO HUDSON BAY AND MANITOBA/ONTARIO
WEDNESDAY/WEDNESDAY NIGHT...WITH THE RIDGE EDGING ACROSS LAKE
SUPERIOR THURSDAY NIGHT THROUGH AT LEAST SUNDAY MORNING. WE STILL
EXPECT SOME BREEZY CONDITIONS NEAR THE LAKE SUPERIOR SHORELINE
WEDNESDAY THROUGH THURSDAY /PUSHING ACROSS MUCH OF CENTRAL UPPER
MICHIGAN DURING THE DAY THURSDAY/. WINDS WILL SLOWLY DIMINISH AS THE
LOW CONTINUES TO EXIT EAST AND THE SURFACE HIGH PUSHES OVERHEAD.
AS FOR THE CHANCE OF PRECIPITATION THROUGH THE PERIOD...IT IS PRETTY
MINIMAL. THE SYNOPTIC SNOW WILL ONLY CLIP AREAS NEAR LAKE MICHIGAN
WEDNESDAY INTO WEDNESDAY EVENING. EVEN WITH THE FAVORABLE UPSLOPE
WINDS OFF LAKE SUPERIOR...TEMPERATURES AT AND ABOVE THE SURFACE WILL
BE MARGINAL TO SUPPORT ANY ACCUMULATING SNOW SHOWERS.
COLDER AIR WILL FINALLY COME IN FOR THE END OF THE WORK WEEK...WITH
850MB TEMPERATURES FALLING TO AROUND -11C FRIDAY AFTERNOON...AND -12
TO -14C FRIDAY NIGHT THROUGH AT LEAST SUNDAY /WITH N-NE WINDS
CONTINUING THROUGH SATURDAY/.
THE 25/12Z ECMWF KEEPS THE RIDGE IN PLACE THROUGH TUESDAY...BECOMING
OUT OF PHASE WITH THE 25/18Z GFS BY MONDAY NIGHT /STRONG 1044MB HIGH
OVER NORTHERN MANITOBA AND ONTARIO...COMPARED TO THE 1005MB LOW
ACROSS ONTARIO/. WHILE THE 26/00Z GFS DID COME IT SLIGHTLY BETTER
AGREEMENT...IT JUST CAN NOT BEAT THE RUN TO RUN CONSISTENCY BEING
SHOWN BY THE ECMWF. CUT BACK THE SLIGHT CHANCE POPS GIVEN WITH A
CONSENSUS OF THE MODELS FOR DAY 6/MONDAY TO RIGHT ALONG THE
WISCONSIN BORDER...MINIMIZING THE INFLUENCE OF THE 26/00Z GFS RUN ON
THE POPS.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z TUESDAY NIGHT)
ISSUED AT 1224 AM EST TUE FEB 26 2013
MVFR CIGS AT KIWD AND KCMX SHOULD GIVE WAY TO SCT CLOUDS OVERNIGHT
WITH POSSIBLE DEVELOPMENT OF FOG AND MVFR TO IFR VSBY. KSAW SHOULD
STAY UNDER MVFR CLOUD DECK LONGER OVERNIGHT SO EVEN IF THERE IS SOME
PARTIAL CLEARING LATE TONIGHT...FOG SHOULDN`T BE THAT THICK. ONLY
EXPECT MVFR VSBY REDUCTION AT KSAW. EXPECT IMPROVING CONDITIONS ON
TUESDAY WITH A RETURN TO VFR CONDITIONS BY LATE MORNING/EARLY
AFTERNOON.
&&
.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 258 AM EST TUE FEB 26 2013
A RIDGE OF HIGH PRESSURE ACROSS LAKE SUPERIOR WILL PUSH NORTHWARD
TODAY...IN ADVANCE OF WEAKENING LOW PRESSURE SLIDING FROM SOUTHERN
MISSOURI THIS MORNING TO FAR SOUTHEASTERN LOWER MICHIGAN AND OHIO
WEDNESDAY MORNING...AND EXITING ACROSS NEW YORK WEDNESDAY NIGHT. AS
A RESULT...EXPECT A TROUGH OVER LAKE SUPERIOR WITH STEADY N-NE WINDS
FROM MID AFTERNOON THROUGH THE REST OF THE WORK WEEK. THE STRONGEST
WINDS...WITH A FEW GUSTS NEARING 35KTS CAN BE EXPECTED WEDNESDAY
INTO THURSDAY AS LAKE SUPERIOR BECOMES PINNED BETWEEN THE LOW
PRESSURE SYSTEM TO OUR SOUTHEAST AND STRONG HIGH PRESSURE EDGING IN
FROM THE NORTHWEST. GIVEN THE STRONGER WINDS AND COOLER AIR SLIDING
IN...FREEZING SPRAY WILL BE POSSIBLE. HIGH PRESSURE WILL WIN OUT
FRIDAY...WITH A RIDGE RESIDING ACROSS LAKE SUPERIOR THROUGH AT LEAST
SATURDAY NIGHT.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...ROLFSON
LONG TERM...KF
AVIATION...VOSS
MARINE...KF
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
1228 AM EST TUE FEB 26 2013
.SHORT TERM...(THIS EVENING THROUGH TUESDAY)
ISSUED AT 413 PM EST MON FEB 25 2013
WATER VAPOR IMAGERY AND RUC ANALYSIS SHOW A SPLIT FLOW PATTERN
ACROSS NAMERICA. IN THE SRN STREAM...A WELL-DEFINED MID LEVEL LOW
WAS OVER N TX. IN THE NRN STREAM...A SHORTWAVE TROF EXTENDS FROM
HUDSON BAY TO THE UPPER MISSISSIPPI VALLEY. SOME FLURRIES HAVE BEEN
NOTED IN WI TODAY IN AN AREA OF WEAK ISENTROPIC ASCENT. SOME OF
THOSE FLURRIES MAY HAVE SLIPPED INTO SCTNRL UPPER MI THIS AFTN
ALTHOUGH NO REPORTS HAVE BEEN NOTED. OTHERWISE...MOSTLY CLOUDY SKIES
HAVE BEEN THE RULE TODAY...THOUGH THERE WAS A PERIOD OF MOSTLY SUNNY
SKIES FOR A TIME EARLIER OVER THE FAR W AND NW.
ALTHOUGH THE SHORT TERM PORTION OF THE FCST WILL FEATURE TRANQUIL
WEATHER...CLOUDS AND TEMPS WILL OFFER SOME CHALLENGING ASPECTS TO
THE FCST. UNDER WEAK ISENTROPIC ASCENT...WILL MAINTAIN A MENTION OF
A FEW FLURRIES INTO THE EVENING HRS OVER THE SRN PORTION OF THE FCST
AREA. CLOUD FCST IS NOT CERTAIN AT ALL AND THAT OPENS THE DOOR TO
BIG TEMP BUST POTENTIAL TONIGHT. UNDER LIGHT SW FLOW INTO THE
EVENING...MULTI-LAYERED CLOUDS TO THE SW SHOULD AFFECT MUCH OF THE
FCST AREA. OVERNIGHT...LOW-LEVEL WIND FIELDS BECOME VERY LIGHT WITH
A TREND TO LIGHT EASTERLY LATE WHICH SUGGESTS LITTLE ADVECTION OF
DRIER AIR. THUS...IT WOULD SEEM THAT MUCH OF THE AREA WILL SEE
MOSTLY CLOUDY SKIES TONIGHT. HOWEVER...THE PROXIMITY OF CLEAR SKIES
JUST TO THE W SUGGESTS THE WRN FCST AREA MAY HAVE THE BEST SHOT OF
SEEING A PERIOD OF PARTLY CLOUDY AND POSSIBLY CLEAR SKIES TONIGHT.
ALL IN ALL...THERE IS VERY LOW CONFIDENCE ON SKY CONDITION THRU THE
NIGHT. WITH LIGHT/CALM WINDS AT THE SFC...TEMPS WILL FALL
SIGNIFICANTLY IN SOME AREAS IF SKIES BECOME CLEAR/PARTLY CLOUDY FOR
A TIME. THIS COULD ALSO LEAD TO SOME FOG DEVELOPMENT. AT THIS
POINT...WILL PLAY IT CONSERVATIVE UTILIZING A CONSENSUS APPROACH TO
TEMPS...BUT WILL GO WITH LOWEST MIN TEMPS OVER THE W (MID TEENS)
WHERE IT APPEARS THERE IS A BETTER SHOT OF SEEING LESS CLOUDS FOR AT
LEAST A PORTION OF THE NIGHT. COULD EASILY SEE TEMPS FALL INTO THE
SINGLE DIGITS IF ANY LOCATIONS END UP CLEAR FOR A FEW HRS.
E TO NE WINDS WILL DEVELOP TUE AS UPPER MI FALLS INTO THE NRN
PERIPHERY OF THE CIRCULATION AROUND SRN STREAM LOW. WINDS WILL BE
STRONGEST IN THE MENOMINEE AREA AS A STIFF NE WIND WILL BE THE RULE
IN THE AFTN DUE TO COASTAL CONVERGENCE/FUNNELING DOWN THE BAY.
STRATOCU SHOULD TEND TO BREAK UP AS MODELS SUGGEST SOME DRYING...
BUT THE LWR CLOUDS WILL PROBABLY HANG ON LONGEST WHERE EASTERLY
WINDS UPSLOPE. WHERE LOW CLOUDS SCATTER OUT OR CLEAR...THERE SHOULD
BE A FAIR AMOUNT OF SUNSHINE THRU ONLY SOME HIGH CLOUDS. EXPECT MAX
TEMPS IN THE 30S...COOLEST (LOW 30S) AT LOCATIONS WHERE WINDS ARE
OFF THE LAKES AND IN THE UPSLOPE AREAS. TEMPS COULD RISE TO NEAR 40
IN LOCATIONS THAT SEE DOWNSLOPING WITH EASTERLY WINDS.
.LONG TERM...(TUESDAY NIGHT THROUGH MONDAY)
ISSUED AT 413 PM EST MON FEB 25 2013
THREE SHORTWAVES WILL INFLUENCE THE WEATHER FOR MUCH OF THE EASTERN
HALF OF THE CONUS OVER THE NEXT SEVERAL DAYS AND SETUP THE WEATHER
PATTERN HEADING INTO THE FIRST WEEK OF MARCH.
THE FIRST WAVE IS CURRENTLY SPINNING IN THE SOUTHERN PLAINS AND WILL
EJECT TOWARDS THE LOWER GREAT LAKES ON TUESDAY INTO TUESDAY
NIGHT...WHILE THE NEXT WAVE DIVES SOUTHEAST ACROSS THE CENTRAL
ROCKIES. MODELS HAVE BECOME MUCH MORE CONSISTENT WITH THIS SYSTEM IN
THE LAST 24 HOURS...AS THERE WERE DIFFERENCES IN THE INTERACTION
BETWEEN THE FIRST AND SECOND WAVES...WITH THE MERGER AND NORTHWARD
EXTENT. EVERYTHING SEEMS TO HAVE COME INTO AGREEMENT WITH THE
CONSISTENT ECMWF ON A MORE SOUTHERN TRACK THAT JUST BRUSHES THE FAR
SOUTHEAST PART OF UPPER MICHIGAN /NEAR LAKE MICHIGAN/ WITH LIGHT
SNOW LATE TUESDAY NIGHT INTO WEDNESDAY EVENING. ANY SLIGHT
DIFFERENCES IN THE NORTHWEST EXTENT OF THE TRACK WILL NOT ONLY
AFFECT THE SNOW NEAR LAKE MICHIGAN...BUT ALSO THE POTENTIAL FOR
LIGHT LAKE ENHANCEMENT OR UPSLOPE PRECIPITATION WITH THE
NORTH-NORTHEAST FLOW AROUND THE LOW. WITH THE LIMITED COLD AIR IN
PLACE AT THIS TIME...IT LOOKS LIKE 850MB TEMPS ON WEDNESDAY ARE ONLY
AROUND -5C...SO DELTA-T VALUES ARE FAIRLY MARGINAL. WHEN COMBINING
THAT WITH LIMITED MOISTURE...UNLESS THE FARTHER NW 06Z NAM IS
CORRECT...WOULDN/T THINK AREAS AWAY FROM LAKE MICHIGAN WOULD SEE
MUCH MORE THAN LOW CLOUDS AND UPSLOPE FLURRIES OR LIGHT SNOW OVER
THE NORTH CENTRAL ON WEDNESDAY PENDING ENOUGH MOISTURE. MODELS ARE
IN BETTER AGREEMENT ON LOW LEVEL MOISTURE MOVING IN ON WEDNESDAY
NIGHT AS THE LOW SHIFTS EAST INTO NEW YORK. THIS IS IN RESPONSE TO
ADDITIONAL MOISTURE ASSOCIATED WITH A NORTHERN STREAM SHORTWAVE
MOVING THROUGH SOUTHERN CANADA. THIS WILL LIKELY LEAD TO THE BEST
POTENTIAL FOR PRECIPITATION FOR AREAS NEAR LAKE SUPERIOR WEDNESDAY
NIGHT INTO THURSDAY. 850MB TEMPS ARE STILL MARGINAL THROUGH THIS
PERIOD...BUT DO DROP TO -10C. WITH THE MARGINAL DELTA-T VALUES AND
AN INVERSION HEIGHT SITTING AROUND 4KFT...THINKING THAT THE LIGHT
SNOW SHOWERS WILL REMAIN IN THE NORTH-NORTHEAST FAVORED LOCATIONS OF
NORTHERN UPPER MICHIGAN. STRONGEST SHOWERS SHOULD OCCUR OVER THE
HIGHER TERRAIN OF NORTH CENTRAL UPPER MICHIGAN...WHERE UPSLOPE FLOW
WILL AID THE FORCING SOME. WILL CONTINUE TO MENTION SLIGHTS AND LOW
CHANCE POPS IN THESE AREAS INTO THURSDAY NIGHT.
MEANWHILE...THE THIRD MAIN SHORTWAVE WILL BE DIVING SOUTHEAST
THROUGH THE ROCKIES ON WEDNESDAY NIGHT AND THURSDAY AND AMPLIFY THE
UPPER TROUGH OVER THE EASTERN CONUS. THIS WILL LEAD THE UPPER GREAT
LAKES INTO A COLDER THAN NORMAL PERIOD FOR THE LAST DAY OF FEBRUARY
AND THE FIRST WEEK OF MARCH. WHILE THIS BRINGS GRADUALLY COLDER AIR
/925-900MB TEMPS FALLING TOWARDS -12 TO -14C/...IT WILL ALSO PUSH A
HIGH PRESSURE RIDGE OVER THE AREA FROM A HIGH CENTERED OVER HUDSON
BAY. THIS SUBSIDENCE WILL WORK TO LOWER THE INVERSION HEIGHTS BELOW
3KFT BY FRIDAY MORNING. THEREFORE...WOULD JUST EXPECT LINGERING
LOW CLOUDS AND AN ISOLATED SNOW SHOWER FOR FRIDAY INTO SATURDAY
OVER LOCATIONS NEAR LAKE SUPERIOR. THERE ARE SOME DIFFERENCES IN
THE WIND DIRECTION ROTATING AROUND THE HIGH...BUT WILL MAINLY FOCUS
THE SLIGHT CHANCES OVER THE NORTH CENTRAL.
DIFFERENCES ARRIVE HEADING INTO THE SECOND HALF OF THE WEEKEND WITH
THE HANDLING OF A SHORTWAVE DROPPING THROUGH ON THE BACK SIDE OF
THE RIDGE OVER THE WESTERN CONUS. THE 00Z ECMWF KEEPS THE RIDGE
FARTHER TO THE WEST BEHIND THE SHORTWAVE...WHILE THE 12Z GFS PUSHES
IT INTO THE UPPER GREAT LAKES. DEPENDING ON THE SOLUTION...THIS
WILL EITHER KEEP THE AREA UNDER THE SURFACE RIDGE INTO THE FIRST
PART OF NEXT WEEK OR HAVE THE AREA INFLUENCED BY THE NEXT CLIPPER
SYSTEM APPROACHING FOR MONDAY. WILL GO WITH THE PERSISTENT HIGH AND
DRIER SOLUTION INTO MONDAY.
AFTER A FAIRLY ACTIVE PERIOD FOR THE LAST COUPLE OF WEEKS OF
FEBRUARY...IT/S LOOKING LIKE MARCH WILL COME IN LIKE A LAMB FOR
MUCH OF THE UPPER GREAT LAKES REGION. FORTUNATELY...THIS ACTIVE
PERIOD BROUGHT THE AREA CLOSER TO NORMAL SNOWFALL...ALTHOUGH SOME
LOCATIONS ARE STILL BELOW NORMAL ON SNOWFALL /OUR OFFICE/ AND SNOW
WATER EQUIVALENT /MICHIGAMME RIVER BASIN/. BUT LOOKING AT MODEL RUN
QPF...THE NEXT 10 DAYS DON/T APPEAR TO BE TOO PROMISING FOR
ADDITIONS TO THE SNOW PACK. 00Z ECMWF ONLY SHOWS 10 DAY ACCUMULATION
OF 0.02-0.08 INCH FOR THE ENTIRE CWA. 00Z GFS FOR THE
SIMILAR PERIOD KEEPS VALUES UNDER 0.25 OF AN INCH...WITH MUCH OF
THAT COMING FROM THE SYSTEM BRUSHING THE AREA ON WEDNESDAY AND
THURSDAY. ON THE POSITIVE SIDE...THE EXISTING SNOWPACK WILL REMAIN
IN PLACE AS TEMPERATURES TREND TOWARDS A COOLER THAN NORMAL PERIOD
FOR THE AREA FRIDAY INTO THE NEXT WORK WEEK /HIGHS IN THE 20S AND
LOWS IN THE SINGLE DIGITS ABOVE ZERO/.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z TUESDAY NIGHT)
ISSUED AT 1224 AM EST TUE FEB 26 2013
MVFR CIGS AT KIWD AND KCMX SHOULD GIVE WAY TO SCT CLOUDS OVERNIGHT
WITH POSSIBLE DEVELOPMENT OF FOG AND MVFR TO IFR VSBY. KSAW SHOULD
STAY UNDER MVFR CLOUD DECK LONGER OVERNIGHT SO EVEN IF THERE IS SOME
PARTIAL CLEARING LATE TONIGHT...FOG SHOULDN`T BE THAT THICK. ONLY
EXPECT MVFR VSBY REDUCTION AT KSAW. EXPECT IMPROVING CONDITIONS ON
TUESDAY WITH A RETURN TO VFR CONDITIONS BY LATE MORNING/EARLY
AFTERNOON.
&&
.MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 413 PM EST MON FEB 25 2013
ALTHOUGH HIGH PRES WILL BE DEPARTING...WINDS WILL REMAIN UNDER 20KT
PROBABLY THRU TUE AFTN. THEREAFTER...TIGHTENING PRES GRADIENT BTWN
HIGH PRES TO THE N AND NW AND LOW PRES TRACKING THRU THE LOWER OHIO
VALLEY TO LOWER LAKES TUE/WED WILL RESULT IN NORTHEASTERLY WINDS
INCREASING TO 20-30KT TUE NIGHT THRU WED. MIGHT SEE A FEW GALE FORCE
GUSTS WED OVER THE E HALF. EVEN THOUGH THE LOW CONTINUES TO MOVE E
THU...THE HIGH BUILDING TOWARD THE AREA FROM N WILL MAINTAIN A TIGHT
PRES GRADIENT...RESULTING IN CONTINUED 20-30KT WINDS WITH SOME
GALE FORCE GUSTS POSSIBLE OVER THE E HALF. WINDS WILL THEN VERY
SLOWLY DIMINISH FROM W TO E FRI/SAT AS THE HIGH PRES MOVES CLOSER...
BUT IT WILL PROBABLY BE SAT BEFORE WINDS DROP BLO 20KT ACROSS THE
ENTIRE LAKE. ALONG WITH THE PERIOD OF STRONGER WINDS MID
WEEK...FREEZING SPRAY IS ALSO EXPECTED.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...ROLFSON
LONG TERM...SRF
AVIATION...VOSS
MARINE...ROLFSON
AREA FORECAST DISCUSSION
NWS DULUTH MN
1145 PM CST MON FEB 25 2013
.AVIATION...06Z TAFS
STRATUS WAS EXPANDING OVER THE BRAINERD LAKES/PINE RIVER AREA LATE
THIS EVENING. FOG WAS FORMING AS WELL...BUT ISN`T WIDESPREAD YET.
WE DO EXPECT THE FOG TO EXPAND AND BECOME DENSE IN SPOTS
OVERNIGHT. WE ALSO EXPECT THE MVFR CEILINGS OVER CENTRAL/NORTHERN
WISCONSIN TO EXPAND BACK TO THE NORTH AND WEST TONIGHT INTO
TUESDAY AS THE LOW LEVEL FLOW BECOMES EASTERLY. THE RAP13 LOW
LEVEL CONDENSATION PRESSURE DEFICITS HAD A DECENT HANDLE ON THESE
CEILINGS...AND ALSO SHOW EXPANSION TO THE WEST AND NORTH. WE
BROUGHT SOME OF THE CEILINGS INTO KDLH BY LATE TUESDAY MORNING.
&&
.PREV DISCUSSION... /ISSUED 801 PM CST MON FEB 25 2013/
UPDATE...
MAIN ISSUE IN THE SHORT TERM IS FOG POTENTIAL. CONCERN IS GROWING
THAT DENSE FOG WILL DEVELOP OVER PORTIONS OF OUR CWA. AT THIS
TIME WE ARE MOST CONCERNED WITH CASS COUNTY...EAST SOUTHEAST
TOWARD BURNETT COUNTY. TEMP-DEWPOINT SPREADS ARE LOW IN PARTS OF
THAT AREA...AND SKIES WERE CLEAR. WE`LL HAVE TO MONITOR ELSEWHERE
AS WELL. WE WILL WAIT ANOTHER HOUR OR SO...THEN DECIDE IF AND
WHERE WE WILL ISSUE A DENSE FOG ADVISORY.
PREV DISCUSSION... /ISSUED 550 PM CST MON FEB 25 2013/
AVIATION...00Z TAFS
SOME MVFR CEILINGS REMAINED OVER A PORTION OF NORTHWEST
WISCONSIN...AFFECTING KHYR/KASX/KPBH. SOME OF THE HIGH RES MODELS
SUGGEST THESE CEILINGS MAY DIMINISH SOME ON THE WEST EDGE...BUT
WILL REFORM OR ADVECT BACK TO THE WEST/NORTH AS THE LOW LEVEL FLOW
BECOMES EASTERLY. MORE LOWER CEILINGS WERE JUST SOUTHWEST OF
KBRD...AND THESE MAY REFORM LATER TONIGHT. THE RAP INDICATES THEY
WILL NOT...BUT CONFIDENCE THAT THESE CEILINGS WILL NOT REFORM IS
LOWER THAN AVERAGE.
FOG COULD BECOME AN ISSUE AS WELL OVERNIGHT WITH THE MILD TEMPS
MELTING SNOW TODAY. WE DID KEEP FOG IN ALL OF THE TAFS...AND
BROUGHT SOME IFR CEILINGS AS WELL. WE DID NOT GO TOO LOW ON VSBYS
YET...AND WILL WAIT UNTIL LATER TONIGHT AND SEE HOW THINGS DEVELOP
BEFORE MAKING ANY SIGNIFICANT CHANGES.
PREV DISCUSSION... /ISSUED 327 PM CST MON FEB 25 2013/
SHORT TERM...
THIS AFTERNOON THROUGH TUESDAY AFTERNOON...
QUIET WEATHER CONDITIONS ARE EXPECTED THROUGH THE SHORT TERM WITH
A WEAK RIDGE OF HIGH PRESSURE AT THE SFC IN PLACE ACROSS THE UPPER
MIDWEST. MAIN CONCERNS ARE FOCUSED AROUND TEMPERATURES AND THE
POTENTIAL FOR ANOTHER ROUND OF FOG TONIGHT...POSSIBLY DENSE IN
SOME LOCATIONS.
A WEAK UPPER TROUGH IS CURRENTLY MOVING THROUGH NRN MN/WRN LAKE
SUPERIOR THIS AFTERNOON AND DISSIPATING AS IT MOVES EWD. THERE WAS
A LINE OF LOW CLOUDS AND FLURRIES ASSOCIATED WITH A VERY WEAK SFC
TROUGH OVER NW MN THIS MORNING. HOWEVER...AS THE TROUGH HAS MOVED
EWD INTO THE DRIER AIR UNDER THE RIDGE...IT HAS WEAKENED
SUBSTANTIALLY THROUGH THE AFTERNOON. MOST OF THE CLOUD COVER HAS
DISSIPATED...AND LEFT ALMOST THE ENTIRE NORTHLAND UNDER MOSTLY
SUNNY SKIES THIS AFTERNOON. THERE IS ALSO AN AREA OF LOW/MID LEVEL
CLOUDS IN NW WI...THAT WILL ATTEMPT TO MOVE EWD...BUT BE REPLACED
QUICKLY BY ADDITIONAL CLOUDS MOVING IN FROM THE SOUTH ASSOCIATED
WITH THE LARGE WINTER STORM OVER THE CENTRAL PLAINS.
THE CLEAR SKIES TODAY HAVE LEAD TO TEMPERATURES REACHING INTO THE
MID TO UPPER 30S. ADDITIONAL TOP LAYER SNOW MELT LIKELY OCCURRED
ONCE AGAIN TODAY. SO...WITH THE CLEAR SKIES TONIGHT ALLOWING
TEMPERATURES TO FALL INTO THE TEENS...INCREASED LOW LEVEL
MOISTURE...LIGHT WINDS...AND A STRONG INVERSION ALOFT. THE THREAT
FOR FOG...POSSIBLY DENSE IN SOME LOCATIONS EXISTS AGAIN TONIGHT.
THE MOST FAVORABLE AREA FOR FOG APPEARS TO BE OVER NE MN...WITH
LIGHTER WINDS AND MOVE CLEARING. WHILE MUCH OF NW WI IS EXPECTED
TO REMAIN UNDER THE INFLUENCE OF MID/HIGH LEVEL CLOUDS AND
STRONGER MIXING.
TUESDAY IS EXPECTED TO BE ANOTHER PLEASANT DAY WITH MOSTLY SUNNY
TO PARTLY CLOUDY SKIES AFTER THE FOG BURNS OFF IN THE
MORNING...LIGHT WINDS AND TEMPERATURES IN THE MID TO UPPER
30S...POSSIBLY CLOSE TO 40 IN A FEW LOCATIONS.
LONG TERM...
TUESDAY NIGHT THROUGH MONDAY...
SOME LAKE EFFECT SNOW SHOWERS WILL LIKELY BE ONGOING ACROSS
NORTHERN PORTIONS OF WISCONSIN TUESDAY NIGHT AND INTO
WEDNESDAY...AS NORTHEAST WINDS BLOW ACROSS LAKE SUPERIOR FOR LONG
FETCH SNOW BANDS TO DEVELOP. AN INTENSE WINTER STORM WILL BE
ONGOING SOUTHEAST OF THE CWA WITH HIGH PRESSURE GENERALLY IN
CONTROL ACROSS OUR CWA. A TROUGH WILL LIKELY DEVELOP FROM THE LOW
PRESSURE SYSTEM MOVING THROUGH THE GREAT LAKES...WHICH MAY
ULTIMATELY BRING SOME BOUTS OF CLOUDINESS FOR THE REST OF THE WORK
WEEK...BUT IT WILL HAVE TO BATTLE UPPER LEVEL RIDGING AND HIGH
PRESSURE AS WELL. OVERALL IT LOOKS GENERALLY DRY FOR THE EXTENDED
TIME PERIOD AND WITH HIGHS IN THE UPPER 20S TO LOWER 30S. DAYTIME
MELTING MAY ALSO RESULT IN SOME FOG AT TIMES.
&&
.POINT TEMPS/POPS...
DLH 11 37 20 35 / 10 0 10 10
INL 10 38 14 34 / 0 0 0 10
BRD 7 35 18 35 / 10 0 0 0
HYR 8 37 20 36 / 10 10 20 20
ASX 13 34 23 34 / 10 0 20 30
&&
.DLH WATCHES/WARNINGS/ADVISORIES...
MN...DENSE FOG ADVISORY UNTIL 9 AM CST TUESDAY FOR MNZ025-033>036-038.
WI...DENSE FOG ADVISORY UNTIL 9 AM CST TUESDAY FOR WIZ006.
&&
$$
SHORT TERM...MELDE
LONG TERM....DAP
AVIATION...MELDE
AREA FORECAST DISCUSSION...UPDATED
NWS TWIN CITIES/CHANHASSEN MN
1015 PM CST MON FEB 25 2013
.UPDATE...ADDED A FEW MORE COUNTIES TO THE DENSE FOG ADVISORY WITH
VISIBILITIES DETERIORATING TO THE SOUTH OF METRO. DID NOT WANT TO
LEAVE THE TWIN CITIES AS AN ISLAND IN THE ADVISORY. OUR LOCAL
HOPWRF AND HRRR WOULD SUGGEST LOWERING CONDITIONS IN THE HEART OF
THE TWIN CITIES AFTER 3 AM.
&&
.DISCUSSION... /ISSUED AT 303 PM CST MON FEB 25 2013/
A RATHER BENIGN FORECAST PERIOD IS AHEAD FOR THE LOCAL AREA...AS
EYES ARE FOCUSED TO THE SOUTH WITH THE POTENT WINTER STORM
UNDERWAY. FOR THE MPX CWA...THE PRIMARY CONCERNS THIS FORECAST
PERIOD ARE FOG TONIGHT AND SNOWFALL CHANCES FOR TOMORROW NIGHT
INTO WEDNESDAY.
FOG AND LOW CLOUDS HAVE BEEN VERY SLOW TO ERODE TODAY...WITH THE
LIGHT WINDS AND LOITERING HIGH PRESSURE RIDGE FIRMLY IN PLACE.
HAVE FINALLY MADE SOME HEADWAY IN THE CLEARING THIS
AFTERNOON...BUT THINK FOG REDEVELOPMENT IS QUITE POSSIBLE AGAIN
TONIGHT...ESPECIALLY FROM CENTRAL INTO WEST CENTRAL MN WHERE
TEMP/DEWPOINT SPREADS ARE LOW AND WINDS WILL REMAIN LIGHT THROUGH
THE NIGHT. HAVE HIGHLIGHTED THE POTENTIAL FOR PATCHY DENSE FOG IN
THE HWO AND GRIDS...AND WILL MONITOR FOR THE POTENTIAL NEED FOR AN
ADVISORY THIS EVENING AS THE CLEARING EVOLVES.
ON TUESDAY...NORTHEAST WINDS INCREASE AS THE AFOREMENTIONED LOW
PRESSURE SYSTEM LIFTS ACROSS THE OH VALLEY. ON TUESDAY NIGHT INTO
WEDNESDAY...WEAK MID LEVEL ENERGY ON THE NORTHERN/WESTERN
PERIPHERY PIVOTS ACROSS CENTRAL WI AND SERN MN. WHILE THE LIFT AND
MOISTURE ARE MODEST...COULD BE SUFFICIENT TO SQUEEZE OUT A FEW
TENTHS OF AN INCH OF SNOW FROM NEAR ALBERT LEA TOWARD EAU
CLAIRE...WHERE SLIGHT CHANCE POPS HAVE BEEN INCLUDED FOR TUESDAY
NIGHT AND WEDNESDAY.
AFTER THAT...CHANCES FOR MEASURABLE SNOW REALLY DO NOT ARRIVE
UNTIL EARLY NEXT WEEK...AS A CLIPPER SYSTEM DIVES SOUTHEAST FROM
CANADA. THERE/S STILL A LARGE AMOUNT OF UNCERTAINTY WITH THE ROUTE
THIS TROUGH WILL TAKE...BUT WESTERN INTO SOUTH CENTRAL MN APPEARS
TO BE THE MORE FAVORED ROUTE FOR LIGHT SNOWFALL ON MONDAY INTO
TUESDAY.
TEMPERATURES WILL VARY LITTLE THROUGH THE FORECAST PERIOD...WITH
HIGHS GENERALLY FROM 25 TO 35...AND LOWS FROM 10 TO 25.
&&
.AVIATION... /00Z TAF ISSUANCE/
CLOUDS AND FOG CONTINUE TO BE THE MAIN ISSUES. MVFR/IFR CLOUDS
STRADDLING THE EAST/WEST MINNESOTA BORDERS SHOULD FILL IN AGAIN
TONIGHT...WITH LIFR/VLIFR FOG EXPECTED ACROSS THE MINNESOTA RIVER
VALLEY. NNE WINDS WILL INCREASE ACROSS WESTERN WI AND SOUTHEASTERN
MN ON TUESDAY...WITH A GRADUAL IMPROVEMENT DURING THE AFTERNOON.
KMSP...
VFR CONDITIONS SHOULD LAST FOR THE NEXT FEW HOURS BEFORE MVFR
CIGS/VISBYS SPREAD ACROSS THE REGION TONIGHT. AT THIS TIME NOT
ANTICIPATING DROPPING BELOW 1700FT OR 4SM. LIGHT WINDS WILL
GRADUALLY BECOME NNE BY MORNING.
/OUTLOOK FOR KMSP/
WED...MVFR EARLY...THEN VFR. WINDS NNW AT 10G15KTS.
THU...VFR WITH MVFR CIGS POSSIBLE. WINDS N AT 5G10KTS.
FRI...VFR WITH MVFR CIGS POSSIBLE. WINDS N AT 10G15KTS.
&&
.MPX WATCHES/WARNINGS/ADVISORIES...
MN...DENSE FOG ADVISORY UNTIL 9 AM CST TUESDAY FOR ANOKA-BENTON-BLUE
EARTH-BROWN-CARVER-CHIPPEWA-CHISAGO-DAKOTA-DOUGLAS-GOODHUE-
HENNEPIN-ISANTI-KANABEC-KANDIYOHI-LAC QUI PARLE-LE SUEUR-
MCLEOD-MEEKER-MILLE LACS-MORRISON-NICOLLET-POPE-RAMSEY-
REDWOOD-RENVILLE-RICE-SCOTT-SHERBURNE-SIBLEY-STEARNS-STEELE-
STEVENS-SWIFT-TODD-WASECA-WASHINGTON-WRIGHT-YELLOW MEDICINE.
WI...DENSE FOG ADVISORY UNTIL 9 AM CST TUESDAY FOR PIERCE-POLK-ST.
CROIX.
&&
$$
RAH/LS/JLB
AREA FORECAST DISCUSSION
NWS RALEIGH NC
255 AM EST TUE FEB 26 2013
.SYNOPSIS...
A POWERFUL STORM SYSTEM WILL MOVE FROM THE SOUTHERN PLAINS INTO THE
OHIO VALLEY TODAY... BRINGING A COLD FRONT FROM SOUTHWEST TO
NORTHEAST THROUGH NORTH CAROLINA LATE TODAY THROUGH TONIGHT. AS DEEP
LOW PRESSURE SLIDES EAST ACROSS THE MIDATLANTIC REGION AND NORTHEAST
STATES WEDNESDAY INTO THURSDAY... GENERALLY DRY WEATHER WITH PERIODS
OF CLOUDS ARE EXPECTED OVER OUR AREA.
&&
.NEAR TERM /THROUGH TUESDAY NIGHT/...
AS OF 955 PM MONDAY...
HIGH AND MID LEVEL CLOUDS HAVE RETURNED TO THE SECTIONS OF THE
WESTERN AND NORTHERN PIEDMONT THAT EARLIER THIS EVENING EXPERIENCED
PARTIAL CLEARING. LOW LEVEL NE WINDS CONTINUE TO FEED COOL DRY AIR
INTO THE REGION. LATEST SFC WET BULB ANALYSIS HAS WET BULB TEMPS
BELOW FREEZING ACROSS THE NORTHERN PIEDMONT AND THE NORTHERN COASTAL
PLAIN. NEAR TERM MODEL GUIDANCE HAS A GOOD HANDLE ON THIS SCENARIO
WITH SFC WET BULBS BELOW FREEZING ACROSS ALL OF THE PIEDMONT AND
MUCH OF THE COASTAL PLAIN BY MIDNIGHT THEN SLOWLY RETREAT NWD WITH
TIME.
MODEL TIMING OF THE MAIN PRECIP SHIELD CONTINUES TO SLOW/LAG PER
LATEST RADAR TRENDS. THE LATEST HRRR VERIFYING WELL WITH THE MAIN
PRECIP AREAS ACROSS THE LOWER MS VALLEY AND THE DEEP SOUTH BUT IS
OVEREMPHASIZING THE SPOTTY PRECIP OUT AHEAD THAT SHOULD BE OCCURRING
ACROSS THE SAVANNAH RIVER VALLEY. STILL APPEARS THAT PRECIP WILL
LIKELY NOT REACH OUR SOUTHERN COUNTIES UNTIL 2-4 AM...THEN EXPAND TO
THE NNE. BASED ON PRECIP TIMING AND CURRENT ANTECEDENT
CONDITIONS...ENOUGH COOLING MAY OCCUR IN THE LOWER LEVELS TO CAUSE
THE RAIN TO EITHER START OUT BRIEFLY OR MIX WITH FREEZING AND/OR
SLEET BEFORE TRANSITIONING TO ALL RAIN. WINTRY PRECIP AMOUNTS DON`T
APPEAR ENOUGH TO CAUSE ANY ACCUMULATION OR WIDESPREAD TRAVEL
PROBLEMS. SPS SHOULD COVER THE SCENARIO...IF IT OCCURS.
LITTLE CHANGE REQUIRED TO HOURLY TEMP/MIN TEMP FORECAST. -WSS
TUESDAY...
A POTENT UPPER LEVEL LOW AND ATTENDANT SFC LOW WILL TRACK NORTHEAST
INTO THE CENTRAL MS RIVER VALLEY BY 12Z TUE...AND INTO THE TN/OH
VALLEY BY 00Z WED. SOUTHWEST FLOW ALOFT IS EXPECTED DOWNSTREAM OVER
THE CAROLINAS.
PRECIPITATION CHANCES:
FORCING FOR PRECIP ON TUE WILL BE COMPRISED OF STRONG LOW-LEVEL WARM
ADVECTION...INCREASINGLY DIFFLUENT FLOW ALOFT DOWNSTREAM OF THE
AFOREMENTIONED UPPER LEVEL LOW PROGRESSING TOWARD THE OH VALLEY...
AND SMALL AMPLITUDE DISTURBANCES IN SW FLOW ALOFT. THE STRONGEST
UPPER LEVEL FORCING ASSOC/W SHORTWAVE ENERGY ROTATING AROUND THE
UPPER LOW SHOULD REMAIN LARGELY WEST/NW OF CENTRAL NC THROUGH THE
DAY TUE. THE MAIN CHANGE WITH THE FORECAST TODAY IS A SLOWER ONSET
TO PRECIP. THE SLOWER ONSET VIA THE 12Z MODEL RUNS AND SIMULATED REF
FORECASTS MAY BE DUE TO THE DRY ANTECEDENT AIRMASS IN PLACE AND MCS
ACTIVITY EXPECTED TO DEVELOP UPSTREAM OVER THE DEEP SOUTH LATE THIS
AFT/EVE INTO TONIGHT...WHICH COULD ALTER THE LOW-LEVEL HEIGHT/WIND
PATTERN OVER THE SOUTHEAST PRIOR TO THE DEVELOPMENT OF A STRONG SE
LLJ DURING THE DAY TUE. ALL MODEL GUIDANCE STILL GENERATES A GOOD
1.00-1.50" OF RAIN ACROSS THE AREA. DESPITE MCS ACTIVITY UPSTREAM
OVER THE DEEP SOUTH TONIGHT...A STRONG SOUTHEASTERLY LOW-LEVEL JET
/ATLANTIC MOISTURE FEED/ IS ANTICIPATED DURING THE DAY TUE...AND
SHOULD ALLOW FOR MODERATE TO OCCASIONALLY HEAVY RAIN ACROSS THE
AREA...ENHANCED BY THE PRESENCE OF MARGINAL MUCAPE ASSOC/W THE H85
WARM NOSE ATOP THE WEDGE...WHICH COULD RESULT IN ISOLD ELEVATED
CONVECTION BETWEEN 12-18 OR 12-21Z.
TEMPERATURES:
VERY CHALLENGING TEMPERATURE FCST. THE LATEST MODEL GUIDANCE STILL
APPEARS TO BE HAVING DIFFICULTY CAPTURING THE WEDGE EXPECTED TO
DEVELOP TUE MORNING. GIVEN DEWPOINTS IN THE LOWER/MID 20S AND
LOWER-THAN-EXPECTED TEMPERATURES THIS AFTERNOON...RANGING FROM THE
UPPER 30S TO LOWER 40S...EXPECT THAT THE STAGE IS SET FOR THE
DEVELOPMENT OF A STRONG CAD WEDGE AT THE ONSET OF PRECIP TUE
MORNING. WILL BASE THE TEMPERATURE FCST MORE-SO ON PATTERN
RECOGNITION IN THIS TYPE OF SETUP...WITH HIGHS ON TUE RANGING FROM
THE UPPER 30S/LOWER 40S IN THE TRIAD TO LOWER/MID 60S IN THE FAR SE
COASTAL PLAIN...IN CLOSER PROXIMITY TO A WAVE OF LOW PRESSURE
EXPECTED TO DEVELOP ALONG THE EASTERN PERIPHERY OF THE WEDGE.
SEVERE THREAT:
THE LATEST DAY 2 OUTLOOK FROM THE STORM PREDICTION CENTER INCLUDES
THE BULK OF CENTRAL NC (ASIDE FROM THE FAR N/NW PIEDMONT) IN A
SLIGHT RISK FOR SEVERE THUNDERSTORMS. HOWEVER...PATTERN RECOGNITION
AND PREVIOUS EXPERIENCE WOULD SUGGEST THAT MODEL GUIDANCE IS NOT
PROPERLY HANDLING THE WEDGE AIRMASS EXPECTED TO DEVELOP AND THAT THE
BAROCLINIC ZONE...ENSUING CYCLOGENESIS...AND BRIEF/NARROW WARM
SECTOR TUE AFTERNOON WILL LARGELY REMAIN EAST OF CENTRAL NC. AS A
RESULT...FEEL THAT THE BEST CHANCE OF SFC-BASED CONVECTION WILL
REMAIN OVER EASTERN (ESP. COASTAL) NC. IT IS AT LEAST POSSIBLE THAT
THE WEDGE FRONT COULD BRIEFLY MOVE FURTHER INLAND ACROSS THE
SOUTHEAST COASTAL PLAIN IN ASSOC/W STRENGTHENING SE LOW-LEVEL FLOW
TUE AFTERNOON...AND A LOW-END POTENTIAL FOR ISOLD SEVERE CONVECTION
OF THE HIGH SHEAR/LOW CAPE VARIETY CANNOT BE RULED OUT...PRIMARILY
IN CUMBERLAND...SAMPSON AND WAYNE COUNTIES. -VINCENT
&&
.SHORT TERM /WEDNESDAY THROUGH THURSDAY NIGHT/...
AS OF 150 AM TUESDAY...
FOR WEDNESDAY/WEDNESDAY NIGHT: THE MID LEVEL VORTEX IS EXPECTED TO
BE OVER NRN OH WEDNESDAY MORNING WITH A SECONDARY LOW NEAR STL ALONG
A TRAILING TROUGH... WHILE SURFACE LOWS WITH THE OCCLUDED FRONTAL
SYSTEM SIT OVER THE NRN OH/IN BORDER AND NEAR PHL. THE LEADING COLD
FRONT WILL BE PUSHING WELL OFF THE COAST WITH DEEP CYCLONIC WSW FLOW
OVER NC... AWAITING THE SECONDARY COLD FRONT PASSAGE AS THE OH/IN
LOW TRACKS EAST TO NY/PA WEDNESDAY NIGHT. THE COLUMN WILL DRY OUT BY
DAYBREAK WEDNESDAY BUT THE WSW LOW LEVEL FLOW WILL NOT INITIALLY
PERMIT A LOT OF DRYING IN THE EVENTUAL MIXED LAYER... SO BENEATH THE
INVERSION ALOFT WE SHOULD SEE SCATTERED-BROKEN FLAT CUMULUS
ESPECIALLY IN THE AFTERNOON. THE NAM/GFS/ECMWF DEPICT A BRIEF
RESURGENCE IN LOW LEVEL MOISTURE TRANSPORT EAST OF HIGHWAY 1
WEDNESDAY LATE AFTERNOON/EVENING... ALONG AND AHEAD OF THE SECONDARY
COLD FRONT ACCOMPANIED BY A SHEARED VORTICITY LOBE ALONG THE PASSING
MID LEVEL TROUGH AXIS. THE MOISTURE RETURN DOES NOT APPEAR TO BE
SUFFICIENT ANY APPRECIABLE PRECIP... PARTICULARLY CONSIDERING THAT
ANY DYNAMIC FORCING FOR ASCENT WILL BE WEAK AND ROOTED IN THE HIGH
LEVELS... LIMITED TO DPVA AND UPPER DIVERGENCE (WITH THE 160 KT
JETLET OVER THE SC COAST)... BUT WILL CONTINUE TO KEEP AN EYE OUT
FOR THIS POTENTIAL ACROSS THE NRN TIER OF CENTRAL NC COUNTIES... AS
THE GFS DOES GENERATE LIGHT QPF OVER THE VA BORDER AND NRN NC AS THE
700 MB TROUGH PASSES THROUGH THE AREA WEDNESDAY NIGHT. FORECAST
SOUNDINGS AND THE DRY ADIABATIC PROFILE IN THE MIXED LAYER SUPPORT
HIGHS OF 56-64... UNDER PARTLY TO MOSTLY CLOUDY SKIES. LOWS
WEDNESDAY NIGHT 33-38 AS CLOUDS... BREEZE... AND DELAY IN LOW LEVEL
COLD AIR ADVECTION LIMIT COOLING. EXPECT A STOUT SW BREEZE WEDNESDAY
WITH PERIODIC GUSTS TO 25 KTS AS 925 MB WINDS OF 20-30 MPH PARTIALLY
MIX DOWN TO THE SURFACE MAINLY IN THE AFTERNOON/EVENING.
FOR THURSDAY/THURSDAY NIGHT... THE MID LEVEL LOW OVER NY/PA HEADS
SLOWLY EAST... EVENTUALLY PASSING OFF THE NORTHEAST COAST LATE
THURSDAY OR THURSDAY NIGHT WITH STRONG MID LEVEL HEIGHT RISES
(50-100 METERS) OVER NC. WE WILL MAINTAIN A DEEP CYCLONIC FLOW OVER
NC WITH ENHANCED MOISTURE PERSISTING IN THE 850-700 MB LAYER... SO
EXPECT CONTINUED PARTLY TO MOSTLY CLOUDY SKIES THURSDAY... GREATEST
COVERAGE NORTH... CLEARING THURSDAY NIGHT AS THE 700 MB TROUGH HEADS
TO OUR EAST FOLLOWED BY DOWNSLOPE DRYING. LOW LEVEL THICKNESSES DROP
BACK TO 10-15 METERS BELOW NORMAL... INDICATIVE OF HIGHS REACHING
49-56... WITH NW WINDS OF 10-20 KTS GUSTING TO 25 KTS AS WE MIX UP
TO 800 MB WITH A TIGHT MSLP GRADIENT. LOWS 28-33 WITH DIMINISHING
WINDS. -GIH
&&
.LONG TERM /FRIDAY THROUGH MONDAY/...
AS OF 250 AM TUESDAY...
CHILLY AND UNSETTLED THIS WEEKEND... AND THE RISK OF LIGHT RAIN OR
SNOW SHOWERS PARTICULARLY ON SATURDAY IS INCREASING.
AS THE VORTEX SHIFTS FURTHER OFF THE NORTHEAST COAST ON FRIDAY...
HIGH PRESSURE CLOSES OFF OVER NORTHERN LOWER MI... WHILE SHORTWAVE
ENERGY UNDERCUTS THE ANTICYCLONE... DROPPING FROM THE UPPER MIDWEST
INTO THE CENTRAL MISS VALLEY WHERE IT BRIEFLY CLOSES OFF. WITH LIGHT
MAINLY NORTHERLY SURFACE FLOW AND FLAT DECELERATING MID LEVEL
FLOW... FRIDAY SHOULD BE RELATIVELY QUIET BUT COOL AS LOW LEVEL
THICKNESSES DROP ANOTHER 10 METERS FROM THURSDAY. HIGHS 47-53 UNDER
PARTLY CLOUDY SKIES. LOWS 28-34.
THE LOW NEAR MEMPHIS LATE FRIDAY SHIFTS EASTWARD ACROSS SRN TN AND
INTO NC/VA BY LATE SATURDAY... A SCENARIO AGREED UPON FAIRLY WELL BY
THE OP GFS AND ECMWF AND GENERALLY SUPPORTED BY THE EACH MODEL`S
ENSEMBLE MEAN. THE GFS HAS BEEN TRENDING TOWARD GREATER AMPLITUDE...
AND BY ALL ACCOUNTS THIS IS EXPECTED TO BE AN ANOMALOUSLY DEEP
TROUGH OVER THE SOUTHEAST STATES... 3-4 STANDARD DEVIATIONS BELOW
NORMAL AND UNUSUAL 100+ METER HEIGHT FALS OVER FL AND THE EASTERN
GULF. WEAK LOW PRESSURE IS EXPECTED TO FORM OVER THE DEVELOPING
BAROCLINIC ZONE OFF THE NC COAST SATURDAY... AND THE RESULANT
NORTHEAST LOW LEVEL FLOW SHOULD HELP DRAW IN LOW LEVEL ATLANTIC
MOISTURE TO COINCIDE WITH DYNAMIC COOLING AND SATURATION ALOFT AS
THE CORE OF THE LOW APPROACHES. GFS BUFR SOUNDINGS BECOME QUITE
MOIST (NEARLY SATURATED) FROM THE SURFACE TO 500 MB LATE SATURDAY
AND SATURDAY NIGHT... WITH A PROFILE THAT IS ENTIRELY BELOW FREEZING
(TO AS COLD AS -25C TO -30C) EXCEPT PERHAPS RIGHT NEAR THE GROUND.
FORECAST MID LEVEL LAPSE RATES ARE IMPRESSIVE... 6.5-7.3 C/KM FROM
850-500 MB FROM SATURDAY AFTERNOON THROUGH SUNDAY ON THE GFS
(ALTHOUGH THEY ARE A BIT LOWER AT 6.0 C/KM ON THE ECMWF)... AND
BASED ON THE MODEL TRENDS TOWARD A STRONGER SYSTEM AND WETTER AND
MORE UNSTABLE PROFILE... WILL INTRODUCE A SMALL CHANCE OF LIGHT RAIN
OR LIGHT SNOW LATE SATURDAY THROUGH MIDDAY SUNDAY. THE SPECIFIC TYPE
WILL DEPEND ON THE WET BULB PROFILE IN THE LOWEST 1-2 THOUSAND FEET
AGL... A FACTOR THAT IS IMPOSSIBLE TO SPECIFY THIS FAR OUT IN TIME.
WILL LOWER FORECAST HIGHS A BIT SATURDAY/SUNDAY... IN THE 40S... AS
WE SHOULD SEE EXPANSIVE CLOUD COVER FOR THE MAJORITY OF BOTH DAYS.
LOWS 26-32.
THE LOW IS EXPECTED TO LIFT TO OUR NORTHEAST SUNDAY NIGHT... AND
WITH DEEP DRYING/SUBSIDENCE AND RISING HEIGHTS IN ITS WAKE... EXPECT
FAIR AND CHILLY WEATHER MONDAY WITH THICKNESSES 30-40 METERS BELOW
NORMAL. HIGHS ONCE AGAIN IN THE MID-UPPER 40S. -GIH
&&
.AVIATION /06Z TUESDAY THROUGH SATURDAY/...
AS OF 1245 AM TUESDAY...
OBSERVATIONS MISSING FROM KRWI. A NOTAM HAS BEEN ISSUED AND THE KRWI
TAF MAY NOT BE AMENDED UNTIL OBSERVATIONS RETURN.
VFR CONDITIONS CONTINUE AT NEARLY ALL LOCATIONS ACROSS CENTRAL NC AS
LOW CLOUDS HOLD TO OUR SOUTH ACROSS GA AND SC. NEAR TERM MODELS
SHOW THESE MVFR CEILINGS SPREADING TOWARD KFAY AND KGSO/KINT BETWEEN
08-10Z AS A LARGE AREA OF RAIN SPREADS INTO THE REGION AHEAD OF A
LOW PRESSURE SYSTEM MOVING OUT OF THE DEEP SOUTH. CONDITIONS WILL
DETERIORATE QUICKLY AFTER 12Z...WITH CEILINGS AND VSBYS DROPPING
INTO THE IFR/LIFR RANGE AND PERIODS OF MODERATE TO HEAVY RAIN. LOW
LEVEL WIND SHEAR WILL ALSO BE A CONCERN BETWEEN 15Z AND 21Z AS A
STRONG SOUTHERLY LOW LEVEL JET OF OVER 50 KT SURGES ATOP THE
NORTHEASTERLY SURFACE WINDS. ISOLATED THUNDERSTORMS WILL BE
POSSIBLE DURING THE AFTERNOON...MOSTLY FROM KRDU SOUTH AND
EAST...THOUGH THERE IS A BIT MORE UNCERTAINTY REGARDING WHETHER
STORMS WILL BE ABLE TO DEVELOP.
SOME IMPROVEMENT IN CONDITIONS IS EXPECTED AFTER 00Z WEDNESDAY AS A
SOUTHWESTERLY WIND DEVELOPS AND A DRY FRONT SWEEP ACROSS THE AREA.
HOWEVER...THE RESIDUAL POOL OF MOISTURE OVER THE WESTERN PIEDMONT
MAY LEAD TO A GREATER PROBABILITY OF MVFR/IFR CEILINGS AT KGSO/KINT
OVERNIGHT.
OUTLOOK...
VFR CONDITIONS ARE EXPECTED TO RETURN TO THE AREA EARLY WEDNESDAY
MORNING BEHIND THE DEPARTING FRONT AND THEN PERSIST THROUGH THE
REMAINDER OF THE WEEK.
&&
.RAH WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...HARTFIELD
NEAR TERM...WSS/VINCENT
SHORT TERM...HARTFIELD
LONG TERM...HARTFIELD
AVIATION...KRR/SMITH
AREA FORECAST DISCUSSION
NWS RALEIGH NC
1245 AM EST TUE FEB 26 2013
.SYNOPSIS...
A POTENT STORM SYSTEM WILL MOVE FROM THE LOWER MIDWEST INTO THE OHIO
VALLEY LATE TONIGHT AND TUESDAY. AN ASSOCIATED COLD FRONT WILL MOVE
EAST ACROSS CENTRAL NORTH CAROLINA TUESDAY NIGHT AND WEDNESDAY
MORNING.
&&
.NEAR TERM /TONIGHT/...
AS OF 955 PM MONDAY...
HIGH AND MID LEVEL CLOUDS HAVE RETURNED TO THE SECTIONS OF THE
WESTERN AND NORTHERN PIEDMONT THAT EARLIER THIS EVENING EXPERIENCED
PARTIAL CLEARING. LOW LEVEL NE WINDS CONTINUE TO FEED COOL DRY AIR
INTO THE REGION. LATEST SFC WET BULB ANALYSIS HAS WET BULB TEMPS
BELOW FREEZING ACROSS THE NORTHERN PIEDMONT AND THE NORTHERN COASTAL
PLAIN. NEAR TERM MODEL GUIDANCE HAS A GOOD HANDLE ON THIS SCENARIO
WITH SFC WET BULBS BELOW FREEZING ACROSS ALL OF THE PIEDMONT AND
MUCH OF THE COASTAL PLAIN BY MIDNIGHT THEN SLOWLY RETREAT NWD WITH
TIME.
MODEL TIMING OF THE MAIN PRECIP SHIELD CONTINUES TO SLOW/LAG PER
LATEST RADAR TRENDS. THE LATEST HRRR VERIFYING WELL WITH THE MAIN
PRECIP AREAS ACROSS THE LOWER MS VALLEY AND THE DEEP SOUTH BUT IS
OVEREMPHASIZING THE SPOTTY PRECIP OUT AHEAD THAT SHOULD BE OCCURRING
ACROSS THE SAVANNAH RIVER VALLEY. STILL APPEARS THAT PRECIP WILL
LIKELY NOT REACH OUR SOUTHERN COUNTIES UNTIL 2-4 AM...THEN EXPAND TO
THE NNE. BASED ON PRECIP TIMING AND CURRENT ANTECEDENT
CONDITIONS...ENOUGH COOLING MAY OCCUR IN THE LOWER LEVELS TO CAUSE
THE RAIN TO EITHER START OUT BRIEFLY OR MIX WITH FREEZING AND/OR
SLEET BEFORE TRANSITIONING TO ALL RAIN. WINTRY PRECIP AMOUNTS DON`T
APPEAR ENOUGH TO CAUSE ANY ACCUMULATION OR WIDESPREAD TRAVEL
PROBLEMS. SPS SHOULD COVER THE SCENARIO...IF IT OCCURS.
LITTLE CHANGE REQUIRED TO HOURLY TEMP/MIN TEMP FORECAST.
&&
.SHORT TERM /TUESDAY/...
AS OF 315 PM MONDAY...
OVERVIEW:
A POTENT UPPER LEVEL LOW AND ATTENDANT SFC LOW WILL TRACK NORTHEAST
INTO THE CENTRAL MS RIVER VALLEY BY 12Z TUE...AND INTO THE TN/OH
VALLEY BY 00Z WED. SOUTHWEST FLOW ALOFT IS EXPECTED DOWNSTREAM OVER
THE CAROLINAS.
PRECIPITATION CHANCES:
FORCING FOR PRECIP ON TUE WILL BE COMPRISED OF STRONG LOW-LEVEL WARM
ADVECTION...INCREASINGLY DIFFLUENT FLOW ALOFT DOWNSTREAM OF THE
AFOREMENTIONED UPPER LEVEL LOW PROGRESSING TOWARD THE OH VALLEY...
AND SMALL AMPLITUDE DISTURBANCES IN SW FLOW ALOFT. THE STRONGEST
UPPER LEVEL FORCING ASSOC/W SHORTWAVE ENERGY ROTATING AROUND THE
UPPER LOW SHOULD REMAIN LARGELY WEST/NW OF CENTRAL NC THROUGH THE
DAY TUE. THE MAIN CHANGE WITH THE FORECAST TODAY IS A SLOWER ONSET
TO PRECIP. THE SLOWER ONSET VIA THE 12Z MODEL RUNS AND SIMULATED REF
FORECASTS MAY BE DUE TO THE DRY ANTECEDENT AIRMASS IN PLACE AND MCS
ACTIVITY EXPECTED TO DEVELOP UPSTREAM OVER THE DEEP SOUTH LATE THIS
AFT/EVE INTO TONIGHT...WHICH COULD ALTER THE LOW-LEVEL HEIGHT/WIND
PATTERN OVER THE SOUTHEAST PRIOR TO THE DEVELOPMENT OF A STRONG SE
LLJ DURING THE DAY TUE. ALL MODEL GUIDANCE STILL GENERATES A GOOD
1.00-1.50" OF RAIN ACROSS THE AREA. DESPITE MCS ACTIVITY UPSTREAM
OVER THE DEEP SOUTH TONIGHT...A STRONG SOUTHEASTERLY LOW-LEVEL JET
/ATLANTIC MOISTURE FEED/ IS ANTICIPATED DURING THE DAY TUE...AND
SHOULD ALLOW FOR MODERATE TO OCCASIONALLY HEAVY RAIN ACROSS THE
AREA...ENHANCED BY THE PRESENCE OF MARGINAL MUCAPE ASSOC/W THE H85
WARM NOSE ATOP THE WEDGE...WHICH COULD RESULT IN ISOLD ELEVATED
CONVECTION BETWEEN 12-18 OR 12-21Z.
TEMPERATURES:
VERY CHALLENGING TEMPERATURE FCST. THE LATEST MODEL GUIDANCE STILL
APPEARS TO BE HAVING DIFFICULTY CAPTURING THE WEDGE EXPECTED TO
DEVELOP TUE MORNING. GIVEN DEWPOINTS IN THE LOWER/MID 20S AND
LOWER-THAN-EXPECTED TEMPERATURES THIS AFTERNOON...RANGING FROM THE
UPPER 30S TO LOWER 40S...EXPECT THAT THE STAGE IS SET FOR THE
DEVELOPMENT OF A STRONG CAD WEDGE AT THE ONSET OF PRECIP TUE
MORNING. WILL BASE THE TEMPERATURE FCST MORE-SO ON PATTERN
RECOGNITION IN THIS TYPE OF SETUP...WITH HIGHS ON TUE RANGING FROM
THE UPPER 30S/LOWER 40S IN THE TRIAD TO LOWER/MID 60S IN THE FAR SE
COASTAL PLAIN...IN CLOSER PROXIMITY TO A WAVE OF LOW PRESSURE
EXPECTED TO DEVELOP ALONG THE EASTERN PERIPHERY OF THE WEDGE.
SEVERE THREAT:
THE LATEST DAY 2 OUTLOOK FROM THE STORM PREDICTION CENTER INCLUDES
THE BULK OF CENTRAL NC (ASIDE FROM THE FAR N/NW PIEDMONT) IN A
SLIGHT RISK FOR SEVERE THUNDERSTORMS. HOWEVER...PATTERN RECOGNITION
AND PREVIOUS EXPERIENCE WOULD SUGGEST THAT MODEL GUIDANCE IS NOT
PROPERLY HANDLING THE WEDGE AIRMASS EXPECTED TO DEVELOP AND THAT THE
BAROCLINIC ZONE...ENSUING CYCLOGENESIS...AND BRIEF/NARROW WARM
SECTOR TUE AFTERNOON WILL LARGELY REMAIN EAST OF CENTRAL NC. AS A
RESULT...FEEL THAT THE BEST CHANCE OF SFC-BASED CONVECTION WILL
REMAIN OVER EASTERN (ESP. COASTAL) NC. IT IS AT LEAST POSSIBLE THAT
THE WEDGE FRONT COULD BRIEFLY MOVE FURTHER INLAND ACROSS THE
SOUTHEAST COASTAL PLAIN IN ASSOC/W STRENGTHENING SE LOW-LEVEL FLOW
TUE AFTERNOON...AND A LOW-END POTENTIAL FOR ISOLD SEVERE CONVECTION
OF THE HIGH SHEAR/LOW CAPE VARIETY CANNOT BE RULED OUT...PRIMARILY
IN CUMBERLAND...SAMPSON AND WAYNE COUNTIES. -VINCENT
&&
.LONG TERM /TUESDAY NIGHT THROUGH SUNDAY/...
AS OF 1150 AM MONDAY...
TUESDAY NIGHT...
AS THE STORM SYSTEM LIFTS NORTH INTO VA AND BEYOND... THE TRAILING
COLD FRONT IS FORECAST TO BE DELAYED UNTIL OVERNIGHT THROUGH 12Z
WED IN THE EAST. THE CAD BOUNDARY MAY ACTUALLY BE PULLED BACK
EASTWARD THROUGH THE COASTAL PLAIN AFTER THE LOW PRESSURE PASSES.
RESIDUAL CAD WILL PLAY A ROLE WITH LOW CEILINGS AND VISIBILITIES
WITH FOG AND EVEN SOME LIGHT DRIZZLE OVER THE PIEDMONT TRIAD REGION.
ANY ADDITIONAL QPF WOULD BE 0.01 OR TRACE AMOUNTS. SOME OF THE
WEATHER ASSOCIATED WITH THE RESIDUAL CAD MAY SPREAD BACK EASTWARD
OVER THE COASTAL PLAIN DURING THE OVERNIGHT OUT AHEAD OF THE MAIN
COLD FRONT THAT WILL ARRIVE LATER. THIS FRONT SHOULD PUSH EAST
THROUGH THE REGION BETWEEN 09Z-13Z OR SO... WITH GOOD MIXING OF DRY
AIR ALOFT DOWN TO THE SURFACE FINALLY BRINGING RAPID CLEARING.
EXPECT THIS RAPID CLEARING TO BEGIN IN THE LEE OF THE BLUE RIDGE
THEN SPREAD OUT OVER THE PIEDMONT AND EVENTUALLY THE COASTAL PLAIN
AS THE FRONT PASSES THROUGH. LOWS SHOULD BE HELD UP IN THE EAST AS
THE FRONT WILL BE DELAYED. THE TEMPS MAY DROP JUST BEFORE SUNRISE IN
THE WEST AS THE DRY AIR ARRIVES. LOWS GENERALLY 35-40 NW RANGING TO
NEAR 50 EAST.
WEDNESDAY-SUNDAY...
THE EUROPEAN OPERATIONAL MODEL ALONG WITH THE EC ENSEMBLE MEAN WERE
FAVORED IN THE MEDIUM RANGE PERIOD FROM WED-SUN. A PROGRESSIVELY
COLDER PATTERN IS EXPECTED OVER THE EASTERN UNITED STATES... WITH
THE COLDEST AIR EXPECTED TO ARRIVE TOWARD THE WEEKEND. THERE IS
STILL A LOW CHANCE OF A COASTAL STORM DEPENDING ON THE EXACT
POSITION/STRENGTH OF THE MID/UPPER LEVEL TROUGH THAT DEVELOPS OVER
THE EASTERN UNITED STATES. THE ARCTIC OSCILLATION AND THE NORTH
ATLANTIC OSCILLATION ARE FOREST TO BECOME STRONGLY NEGATIVE DAYS
6-10... WITH CORRESPONDING POSITIVE HEIGHT ANOMALIES SPREADING FROM
GREENLAND WESTWARD INTO FAR EASTERN CANADA IN THE HIGHER
LATITUDES... SUPPORTING COASTAL DEVELOPMENT OFF THE EAST COAST SAT
OR SUNDAY. JUST HOW FAR WEST THIS SYSTEM CAN DEVELOP WILL MEAN
EITHER DRY AND COLDER OR POSSIBLY WHITE AND COLDER OVER THE WEEKEND.
REGARDLESS... THE EASTERN TROUGH AND FORECAST HEIGHT ANOMALIES
SUPPORTS TEMPERATURES A GOOD 10-15 DEGREES BELOW NORMAL SAT-MON.
SENSIBLE WEATHER...
MILD AND PARTLY SUNNY WEDNESDAY...HIGHS 58-65. WESTERLY WINDS 10-20
MPH. PARTLY CLOUDY/PARTLY SUNNY THURSDAY AND FRIDAY. COLDER. LOWS IN
THE 20S TO AROUND 30. HIGHS 50-55 THURS...AND 45-50 FRI.
SAT-SUN...IMPORTANT PERIOD AS THE MID/UPPER TROUGH WILL DIG OVER THE
SOUTHERN APPALACHIANS...SOME COASTAL LOW POTENTIAL. WE WILL KEEP
FORECAST DRY FOR NOW...BUT THIS PATTERN WILL HAVE TO BE WATCHED.
COLD WITH LOWS IN THE 20S. HIGHS IN THE 40S (NEAR 50 SANDHILLS).
MONDAY...COLD AND DRY. LOWS IN THE 20S. HIGHS IN THE 40S.
&&
.AVIATION /06Z TUESDAY THROUGH SATURDAY/...
AS OF 1245 AM TUESDAY...
OBSERVATIONS MISSING FROM KRWI. A NOTAM HAS BEEN ISSUED AND THE KRWI
TAF MAY NOT BE AMENDED UNTIL OBSERVATIONS RETURN.
VFR CONDITIONS CONTINUE AT NEARLY ALL LOCATIONS ACROSS CENTRAL NC AS
LOW CLOUDS HOLD TO OUR SOUTH ACROSS GA AND SC. NEAR TERM MODELS
SHOW THESE MVFR CEILINGS SPREADING TOWARD KFAY AND KGSO/KINT BETWEEN
08-10Z AS A LARGE AREA OF RAIN SPREADS INTO THE REGION AHEAD OF A
LOW PRESSURE SYSTEM MOVING OUT OF THE DEEP SOUTH. CONDITIONS WILL
DETERIORATE QUICKLY AFTER 12Z...WITH CEILINGS AND VSBYS DROPPING
INTO THE IFR/LIFR RANGE AND PERIODS OF MODERATE TO HEAVY RAIN. LOW
LEVEL WIND SHEAR WILL ALSO BE A CONCERN BETWEEN 15Z AND 21Z AS A
STRONG SOUTHERLY LOW LEVEL JET OF OVER 50 KT SURGES ATOP THE
NORTHEASTERLY SURFACE WINDS. ISOLATED THUNDERSTORMS WILL BE
POSSIBLE DURING THE AFTERNOON...MOSTLY FROM KRDU SOUTH AND
EAST...THOUGH THERE IS A BIT MORE UNCERTAINTY REGARDING WHETHER
STORMS WILL BE ABLE TO DEVELOP.
SOME IMPROVEMENT IN CONDITIONS IS EXPECTED AFTER 00Z WEDNESDAY AS A
SOUTHWESTERLY WIND DEVELOPS AND A DRY FRONT SWEEP ACROSS THE AREA.
HOWEVER...THE RESIDUAL POOL OF MOISTURE OVER THE WESTERN PIEDMONT
MAY LEAD TO A GREATER PROBABILITY OF MVFR/IFR CEILINGS AT KGSO/KINT
OVERNIGHT.
OUTLOOK...
VFR CONDITIONS ARE EXPECTED TO RETURN TO THE AREA EARLY WEDNESDAY
MORNING BEHIND THE DEPARTING FRONT AND THEN PERSIST THROUGH THE
REMAINDER OF THE WEEK.
&&
.RAH WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...VINCENT
NEAR TERM...WSS
SHORT TERM...VINCENT
LONG TERM...BADGETT
AVIATION...KRR/SMITH
AREA FORECAST DISCUSSION
NWS GRAND FORKS ND
340 AM CST TUE FEB 26 2013
.SHORT TERM...
THE MAIN CHALLENGE WILL BE FOG AND LOW CLOUDS THROUGH THIS
MORNING...THEN VERY LIGHT SNOW/FLURRY CHANCES WED/WED NIGHT INTO
THU PERHAPS. ALL MODELS ARE DOING POORLY WITH CURRENT LOW CLOUD/FOG
ALONG AND EAST OF THE VALLEY. THE HRRR IS DOING THE BEST AND WILL
FOLLOW THAT FOR THE NEAR TERM. THEREAFTER...MOST MODELS ARE
SIMILAR WITH NO REAL PREFERENCE.
FOR TODAY...THE BIG QUESTION WILL BE HOW LONG DOES THE DENSE FOG
PERSISTS AND ASSOCIATED LOW CLOUDS ALONG AND EAST OF THE RED RIVER
VALLEY. WE WILL CONTINUE TO MONITOR THE POSSIBLE NORTHWARD
EXPANSION OF THE CURRENT DENSE FOG ADVISORY...WITH CLOUDS HOLDING
DOWN TEMPS WHERE THEY PERSIST TODAY. A WEAK SFC HIGH BUILDS IN
WITH RIDGING ALOFT...LENDING MORE CREDENCE TO CLOUDS/FOG
PERSISTING TODAY WHERE THEY ARE AT SUNRISE.
FOR TONIGHT...WEAK CAA BEGINS IN THE NW AND THERE COULD BE FOG/LOW
CLOUDS IN THE SOUTH AND EAST. FOR NOW WON/T MENTION ANY FOG...BUT
MONITOR WITH LATER FORECASTS. TEMPS WILL BE HIGHLY DEPENDENT ON
HOW MUCH CLEARING DEVELOPS.
ON WED/WED NIGHT...THERE WILL BE LOW LEVEL SATURATION UP TO AROUND
800MB IN THE NORTH ADVECTING SOUTH. THERE SHOULD BE AN AREA OF
LIGHT SNOW/FLURRIES MAINLY IN THE NORTH...OR EVEN SOME FREEZING
DRIZZLE WITH MOST OF THE SATURATION AT TEMPS ABOVE -10C. FOR NOW
WON/T MENTION FREEZING DRIZZLE...BUT POTENTIAL IS THERE. TEMPS
WILL BE A BIT COLDER WED WITH LOW LEVEL CAA AND NORTHERLY WINDS
INCREASING A BIT.
FOR THU/THU NIGHT...COOL AIR ADVECTION CONTINUES AND THERE COULD
BE SOME FLURRIES/LOW CLOUDS ON THU WITH A WEAK UPPER TROUGH. FOR NOW
HAVE KEPT IT DRY WITH TEMPS SLOWLY COOLING FROM NORTH TO SOUTH AND
THE COLUMN SLOWLY DRYING OUT.
.LONG TERM (FRI-MONDAY NIGHT)...
MODELS IN FAIR AGREEMENT WITH THE EXTENDED UPPER AIR PATTERN AS
LARGE SCALE POSITIVE PNA DEVELOPS ACROSS THE CONUS FOR THE WEEKEND.
THE RESULT ACROSS THE NORTHERN PLAINS REMAINS A DRY FORECAST FRI TO
SUNDAY WITH NW 500MB FLOW AND INCREASING 1000 TO 500MB THICKNESSES
AS RIDGING WORKS INTO THE REGION. A POTENT WAVE IS EXPECTED TO
DE-AMPLIFY THE RIDGING AND ENTER INTO THE AREA SUNDAY NIGHT INTO
MONDAY...HENCE THE CHC POPS. MODELS TEND TO BREAK DOWN THE POSITIVE
PNA TOO QUICKLY AND HAVE SLOWED THE ARRIVAL OF THE SYSTEM FOR A
COUPLE RUNS ALREADY. WOULDN/T BE SURPRISED IF THE TREND CONTINUES.
NEAR NORMAL TEMPS EXPECTED THROUGH THE PERIOD.
&&
.AVIATION...
LIFR/IFR CONDITIONS IN LOW CLOUDS/FOG CONTINUE ALONG AND EAST OF
THE RED RIVER. EXPECT ALL SITES EXCEPT KDVL TO EXPERIENCE THE LOW
CLOUDS/FOG TO SOME EXTENT. WILL CONTINUE TO MONITOR HOW LONG TO
HANG ONTO THE IFR/LIFR CONDITIONS...AND EXPECT CONDITIONS TO LAST
AT LEAST THROUGH 16Z THIS MORNING...WITH SOME IMPROVEMENT THEREAFTER.
&&
.FGF WATCHES/WARNINGS/ADVISORIES...
ND...DENSE FOG ADVISORY UNTIL 10 AM CST THIS MORNING FOR NDZ039-049-
052-053.
MN...DENSE FOG ADVISORY UNTIL 10 AM CST THIS MORNING FOR MNZ003-024-
027>032-040.
&&
$$
DK/JK
AREA FORECAST DISCUSSION
NWS GREENVILLE-SPARTANBURG SC
343 AM EST TUE FEB 26 2013
.SYNOPSIS...
STRONG LOW PRESSURE WILL MOVE FROM ARKANSAS TO KENTUCKY TODAY WHILE
DRAGGING A WARM FRONT NORTH TOWARD OUR AREA. EXPECT THE WARM FRONT
TO REACH VIRGINIA LATER TONIGHT. A COLD FRONT WILL CROSS OUR REGION
FROM THE NORTHWEST LATE WEDNESDAY.
&&
.NEAR TERM /THROUGH TONIGHT/...
THE NEAR TERM DISCUSSION WILL BE UPDATED AGAIN BY 415 AM TO
REFLECT THE NEW ADVISORY ISSUANCE AND TO UPDATE THE WWA SECTION.
AS OF 230 AM...WENT AHEAD AND ISSUED AN ICE STORM WARNING FOR A
PORTION OF THE CENTRAL MTNS AND HIGHER ELEV OF POLK AND RUTHERFORD
COUNTIES. THE MESONET OBS INDICATE FREEZING OR BELOW TEMPS ACROSS
MANY OF THE VALLEY LOCATIONS AND RIDGES AS WELL. THE INCOMING
PRECIP SHIELD HAS BECOME HEAVIER AND UNIFORMLY WIDESPREAD. EXPECT
FZRA RAIN TO CONTINUE TO AROUND DAYBREAK WITH THE HIGHEST ICE
ACCUMS ARE LIKELY AROUND SRN HENDERSON COUNTY WHERE 0.25 INCHES OR
MORE WILL ACCUMULATE IN GOOD ISENT AND MECH LIFT. OTHER AREAS IN
THE WARNING WILL ALSO SEE NEAR OR WARNING LEVEL ICE ACCUMS THROUGH
12Z. EXPECT WAA TO OVERCOME THE LLVL COLD LAYER AROUND 14Z...BUT
SOME VALLEYS COULD MAINTAIN THE FORMATION OF -FRZA INTO THE LATE
MORNING.
AS OF 100 AM...THE LATEST SFC ANALYSIS INDICATES TW TEMPS AT
FREEZING OR BELOW ACROSS THE ADV AREA AND EVEN OVER THE NRN
FOOTHILLS. WILL MONITOR THE SENSIBLE WX OVER THE NEXT FEW HRS AS THE
PRECIP SHIELD MAKES HEADWAY INTO THE FCST AREA. VERY LIGHT PRECIP
IS NOTED CURRENTLY AND EXPECT DBZ/S TO PICK UP TO AROUND 20/25
AROUND 08Z-09Z ACROSS THE NC MTNS. THE LATEST HRRR KEEPS DECENT
PRECIP ACROSS THE ADV AREA THROUGHOUT IT/S RUN...WHICH MAY LEND
SUPPORT FOR A POSSIBLE UPGRADE TO A WARNING FOR FZRA AS LONG AS LLVL
WAA DOESNT CATCH UP BY THEN. MADE MINOR TWEAKS TO THE GOING GRIDS
FOR T/TD AND WINDS...POP/WX GRIDS STILL LOOK GOOD.
REGIONAL RADAR INDICATED THAT THE SIGNIFICANT RAINFALL WAS LOCATED
ACROSS SOUTHERN AND WESTERN GA. LATEST MODEL RUNS HAVE TRENDED
SLOWER WITH THE ARRIVAL OF THE RA ACROSS THE WESTERN FA AROUND
MIDNIGHT. WIDESPREAD PRECIPITATION IS EXPECTED TO EXPAND ACROSS THE
ENTIRE CWA BY 9Z. FORECAST SOUNDINGS INDICATE THAT A DEEP WARM NOSE
WILL EXIST ACROSS THE REGION TONIGHT...WARMING ABOVE 4C AT 3 KFT BY
LATE TONIGHT. PRECIP THAT FALLS WILL BE EITHER RA OR FZRA...POSSIBLY
SOME IP AT TIMES.
OBSERVATIONS AT 10 PM INDICATE THAT NRN MTNS RANGE FROM THE MID 30S
TO U20S. HOWEVER...TEMPERATURES MAY BECOME STEADY OR GRADUALLY RISE
WITH THE ARRIVAL OF WAA AND LOWER CLOUD COVER. IN ADDITION...LLVL
FLOW...PRECIP...DEEPENING MOISTURE SHOULD RESULT IN A GRADUAL
WARMING OF DEWPOINTS OVERNIGHT. BASED ON THE MARGINAL
TEMPERATURES...FREEZING RAIN SHOULD REMAIN LIMITED TO THE EAST
FACING SLOPES OF THE MTNS FROM HENDERSON TO AVERY...ALONG WITH THE
ADJACENT FOOTHILLS. IN ADDITION...UPSLOPE FLOW MAY AID IN COOLING
TEMPERATURE ALONG THE ESCARPMENT. THESE FACTORS YIELD NEAR WARNING
CRITERIA FREEZING RAIN ALONG THE EAST FACING SLOPES...BUT LIGHT
AMOUNTS ELSEWHERE. I WILL KEEP THE WINTER WEATHER ADVISORY IN PLACE.
WINDS TONIGHT ACROSS THE MTN WILL BECOME QUITE STRONG...PRESSURE
GRADIENT ACROSS THE MTNS TIGHTENS TO AROUND 8 MBS BY 12Z. RIDGETOP
GUSTS SHOULD EXCEED 50 KTS...WITH WINDS BETWEEN 30 TO 40 KTS. THE
COMBINATION OF THE WINDS...WET GROUND...AND ICE ACCUMULATIONS MAY
YIELD TREE AND POWERLINE DAMAGE BY SUNRISE TUESDAY. I WILL UPDATE
THE NPW ALONG WITH THE HWO.
AS OF 630 PM...THE FORECAST APPEARS ON TRACK. I WILL UPDATE THE
T/TD/WINDS TO LATEST OBSERVATIONS.
AS OF 545 PM...I WILL UPDATE THE FORECAST THROUGH TUESDAY. LATEST
REGIONAL RADAR COMPOSITE INDICATES LITTLE TO NO RETURNS ACROSS THE
FORECAST AREA AND ACROSS THE UPSTREAM REGION. THEREFORE...I HAVE
SLOWED THE ARRIVAL OF CATE POPS UNTIL AFTER MIDNIGHT. THEN...ALL
SOLUTIONS INDICATE THAT WIDESPREAD PRECIP WILL OCCUR DURING THE PRE
DAWN HOURS AND EARLY DAYTIME HOURS ON TUESDAY...BEFORE A DRY SLOT
ARRIVES IN THE AFTERNOON.
THE SLOWING OF THE ARRIVAL OF POPS AND SLIGHT QPF FORECAST WILL HAVE
AN IMPACT ON THE ICE FORECAST LATE TONIGHT AND TUESDAY MORNING. THE
LATEST FORECAST WILL FEATURE VALUES APPROACHING 0.25 ALONG THE EAST
FACING SLOPES OF THE NC NRN MTNS...ELSEWHERE ACROSS THE ADJACENT
FOOTHILLS AND VALLEY...VALUES WILL REMAIN LESS THAN A TENTH OF AN
INCH. THE CURRENT WSW APPEARS WELL PLACED AND TIMED FOR ADVISORY
FREEZING RAIN. ONE NOTE...THE SREF GUIDANCE APPEARS VERY HIGH ON
FZRA AMOUNTS. THEREFORE...THE SREF PLUMES AND ANY GUIDANCE BASED ON
THE SREF WILL NOT BE CONSIDERED.
&&
.SHORT TERM /WEDNESDAY THROUGH THURSDAY NIGHT/...
AS OF 330 AM EST TUESDAY...AS WE HEAD TOWARD MARCH...IT LOOKS LIKE
WE ARE HEADING TOWARD WINTER...AT LEAST OVER THE NC MTNS NEAR THE TN
BORDER. WEDNESDAY WILL SEE THE UPPER LOW MOVING SLOWLY OVER THE
UPPER OH VALLEY. THIS WILL KEEP THE FLOW MORE SW TO W ACROSS THE
WESTERN CAROLINAS DURING MOST OF THE DAY DELAYING THE ARRIVAL OF THE
REALLY COLD AIR. HOWEVER...A LARGE VORT LOBE SHOULD PINWHEEL AROUND
THE UPPER LOW AND CROSS THE FCST AREA DURING THE LATE AFTERNOON AND
EARLY EVENING. THAT FEATURE WILL BE THE VANGUARD OF THE COOLER AIR
AND WILL TURN THE FLOW MORE NORTHWESTERLY WEDNESDAY NIGHT. THIS WILL
SERVE TO CRANK UP THE NW FLOW SNOW MAKING MACHINE. POP WAS RAMPED UP
INTO THE LIKELY RANGE NEAR THE TN BORDER AND KEPT THERE THROUGH
THURSDAY NIGHT AS FLOW AND MOISTURE REMAIN VERY FAVORABLE FOR THE
PRODUCTION OF SNOW SHOWERS. ACCUMULATIONS COULD END UP BEING
SIGNIFICANT IN THE FAVORABLE UPSLOPE AREAS NEAR THE TN BORDER...BUT
THE DURATION WILL BE LONG ENOUGH THAT OUR WARNING CRITERIA MIGHT NOT
BE MET. WILL NOT ISSUE A WATCH FOR THIS EVENT BECAUSE OF THE
DURATION V. ACCUM ISSUE...BUT PLAN TO HIT IT HARD IN THE HWO. SOME
OF THE SNOW SHOWERS SHOULD REACH A BIT DEEPER INTO THE MTNS THURSDAY
NIGHT WHEN MOISTURE IS A BIT DEEPER. E OF THE MTNS...IT SEEMS
DOUBTFUL THAT ANY SHOWERS WILL BREACH CONTAINMENT AND SURVIVE E OF
THE BLUE RIDGE. INSTEAD...IT SHOULD BE DRY WITH A PARTLY
CLOUDY/MOSTLY CLEAR SKY...WITH TEMPS A BIT ABOVE NORMAL WEDNESDAY
AND THEN BELOW NORMAL THURSDAY AS THE COLDER AIR REALLY TAKES HOLD.
&&
.LONG TERM /FRIDAY THROUGH MONDAY/...
AS OF 300 AM EST TUESDAY...AS THE DEEP LOW PRESSURE SYSTEM MOVES
FARTHER OFFSHORE FROM LONG ISLAND ON FRIDAY...LOW LEVEL MOISTURE
WILL CONTINUE TO BANK UP AGAINST THE TN AND NC BORDER. THE
NORTHWEST FLOW FROM ACROSS KY AND TN WILL CONTINUE TO PRODUCE
UPSLOPE SNOW SHOWERS FRIDAY AND FRIDAY NIGHT. MEDIUM RANGE MODELS
AGREE ON A DISTURBANCE ROUNDING THE BASE OF THE 500MB TROUGH ON
SATURDAY WITH BROADER ENHANCEMENT OF MOSTLY LIGHT PRECIP ACROSS OUR
REGION. GFS HAS A 536 DECIMETER LOW CENTERED OVER THE SMOKIES AT 18Z
SATURDAY WITH A TENTH OR LESS 6-HOUR PRECIP EXTENDING OVER TO CLT.
THE NEW ECMWF CLOSES A LOW ON FRIDAY AS IT CROSSES TN AND THEN OPENS
IT ONCE IT IS OVER THE NC MTNS AT 18Z SATURDAY. THEREFORE THE TIMING
IS IN SYNC. ECMWF PRECIP IS VERY LIGHT...0.01 TO 0.03 IN 6 HOURS.
AS THIS FEATURE PASSES EAST OF OUR AREA...PRECIP ENDS EAST OF THE
MTNS SATURDAY NIGHT AND SUNDAY AND LIGHT UPSLOPE SNOW SHOWERS COME
TO AN END SUNDAY EVENING ALONG THE NC AND TN BORDER. MOST OF THE
GUIDANCE TONIGHT HAS INCREASING TEMPS BY ONE TO 3 DEGREES...BUT WITH
THE DEPTH OF THE TROUGH AND ALL OTHER LOGICAL METEOROLOGY IT SEEMS
SENSIBLE TO EVEN LOWER TEMPS A DEGREE OR TWO OVER THE WEEKEND.
AFTER THE TROUGH MOVES OFF THE EAST COAST SUNDAY NIGHT...A SHALLOW
RIDGE BUILDS OVER OUR AREA FOR MONDAY RESULTING IN SLIGHTLY HIGHER
THICKNESSES AND A BIT MILDER UNDER PLENTY OF SUNSHINE. EVEN WITH
THIS SLIGHT WARM UP...TEMPS WILL STILL BE ABOUT 8 TO 10 DEGREES
BELOW NORMAL TO START NEXT WEEK.
&&
.AVIATION /09Z TUESDAY THROUGH SATURDAY/...
AT KCLT...WINDS WILL REMAIN NE/LY IN MATURE WEDGE AND HAVE KEPT
PERIODIC LOW END GUSTS THROUGH 13Z. A GENERAL LOWERING OF CIGS WILL
OCCUR OVERNIGHT WITH IFR LIKELY AROUND DAYBREAK. LIGHT RAIN WILL
BECOME MORE MODERATE AND CONSTANT AROUND DAYBREAK AS WELL. THE WEDGE
WILL BREAK DOWN WITH TRIPLE POINT LOW TRACKING NE...SO EMBEDDED
CONVECTION AND TSTMS ARE PROBABLE AFT 18Z TO AROUND 20Z. A DRY SLOT
IS EXPECTED TO MAKE A PUSH TOWARD THE TERMINAL LATER IN THE
AFTERNOON...SO WILL ANTICIPATE IMPROVING CONDS TO MVFR BY 22Z AND
VFR BY 01Z.
ELSEWHERE...A GENERAL REDUCTION IN FLIGHT CATS FROM MVFR TO IFR IS
EXPECTED AT ALL TAF SITES OVERNIGHT. SOME LOW END NE GUSTS WILL
PERSIST ACROSS THE UPSTATE AS THE RAIN SHIELD BECOMES MORE MODERATE
AND WIDESPREAD. WITH THE TIGHT P/GRAD ACROSS THE MTNS...LLWS WILL BE
MAINTAINED IN THE KAVL TAF FOR A COUPLE HRS BEGINNING AT 15Z. THE
DRY SLOT WILL AFFECT THE WESTERN TAF SITES FIRST AND RETURN MVFR/VFR
CONDS AT ALL TERMINALS BY THE EARLY TO MIDDLE AFTERNOON...HOWEVER
KHKY MAY BE STUCK IN MFVR CIG WEDGE CONDS THROUGH THE EVENING.
OUTLOOK...DRY AIR ADV AND CLEARING SKIES WILL CONTINUE WED NIGHT
WITH VFR CONDS EXPECTED THROUGH THURSDAY EAST OF THE MOUNTAINS. SOME
POTENTIAL EXISTS FOR MVFR ACROSS THE NC MTNS WITH SNOW SHOWERS MID
TO LATE WEEK.
CONFIDENCE TABLE...
08-14Z 14-20Z 20-02Z 02-08Z
KCLT HIGH 83% HIGH 87% HIGH 80% HIGH 87%
KGSP MED 77% HIGH 85% MED 78% HIGH 87%
KAVL HIGH 91% HIGH 90% MED 78% HIGH 87%
KHKY HIGH 98% HIGH 86% HIGH 83% HIGH 82%
KGMU MED 77% HIGH 85% MED 77% HIGH 87%
KAND MED 60% HIGH 97% HIGH 80% HIGH 95%
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...HIGH WIND WARNING UNTIL 6 PM EST THIS EVENING FOR NCZ033-
048>052-058-059.
WINTER WEATHER ADVISORY UNTIL 9 AM EST THIS MORNING FOR NCZ033-
048>050-052-501-503-505.
WIND ADVISORY UNTIL 6 PM EST THIS EVENING FOR NCZ033-048>052-
058-059.
ICE STORM WARNING UNTIL 9 AM EST THIS MORNING FOR NCZ053-064-
065-507-509.
FREEZING RAIN ADVISORY UNTIL 9 AM EST THIS MORNING FOR NCZ035-
056-068-069-502-504-506-508-510.
SC...FREEZING RAIN ADVISORY UNTIL 9 AM EST THIS MORNING FOR SCZ002-
003.
&&
$$
SYNOPSIS...DEO
NEAR TERM...SBK
SHORT TERM...PM
LONG TERM...DEO
AVIATION...SBK
AREA FORECAST DISCUSSION
NWS GREENVILLE-SPARTANBURG SC
112 AM EST TUE FEB 26 2013
.SYNOPSIS...
NORTH OF A DEVELOPING WARM FRONT...MOISTURE WILL SPREAD ATOP OUR
REGION FROM THE GULF OF MEXICO. STRONG LOW PRESSURE WILL DRIVE
A COLD FRONT ACROSS OUR AREA ON TUESDAY.
&&
.NEAR TERM /THROUGH TODAY/...
AS OF 100 AM...THE LATEST SFC ANALYSIS INDICATES TW TEMPS AT
FREEZING OR BELOW ACROSS THE ADV AREA AND EVEN OVER THE NRN
FOOTHILLS. WILL MONITOR THE SENSIBLE WX OVER THE NEXT FEW HRS AS
THE PRECIP SHIELD MAKES HEADWAY INTO THE FCST AREA. VERY LIGHT
PRECIP IS NOTED CURRENTLY AND EXPECT DBZ/S TO PICK UP TO AROUND
20/25 AROUND 08Z-09Z ACROSS THE NC MTNS. THE LATEST HRRR KEEPS
DECENT PRECIP ACROSS THE ADV AREA THROUGHOUT IT/S RUN...WHICH MAY
LEND SUPPORT FOR A POSSIBLE UPGRADE TO A WARNING FOR FZRA AS LONG
AS LLVL WAA DOESNT CATCH UP BY THEN. MADE MINOR TWEAKS TO THE
GOING GRIDS FOR T/TD AND WINDS...POP/WX GRIDS STILL LOOK GOOD.
REGIONAL RADAR INDICATED THAT THE SIGNIFICANT RAINFALL WAS LOCATED
ACROSS SOUTHERN AND WESTERN GA. LATEST MODEL RUNS HAVE TRENDED
SLOWER WITH THE ARRIVAL OF THE RA ACROSS THE WESTERN FA AROUND
MIDNIGHT. WIDESPREAD PRECIPITATION IS EXPECTED TO EXPAND ACROSS THE
ENTIRE CWA BY 9Z. FORECAST SOUNDINGS INDICATE THAT A DEEP WARM NOSE
WILL EXIST ACROSS THE REGION TONIGHT...WARMING ABOVE 4C AT 3 KFT BY
LATE TONIGHT. PRECIP THAT FALLS WILL BE EITHER RA OR FZRA...POSSIBLY
SOME IP AT TIMES.
OBSERVATIONS AT 10 PM INDICATE THAT NRN MTNS RANGE FROM THE MID 30S
TO U20S. HOWEVER...TEMPERATURES MAY BECOME STEADY OR GRADUALLY RISE
WITH THE ARRIVAL OF WAA AND LOWER CLOUD COVER. IN ADDITION...LLVL
FLOW...PRECIP...DEEPENING MOISTURE SHOULD RESULT IN A GRADUAL
WARMING OF DEWPOINTS OVERNIGHT. BASED ON THE MARGINAL
TEMPERATURES...FREEZING RAIN SHOULD REMAIN LIMITED TO THE EAST
FACING SLOPES OF THE MTNS FROM HENDERSON TO AVERY...ALONG WITH THE
ADJACENT FOOTHILLS. IN ADDITION...UPSLOPE FLOW MAY AID IN COOLING
TEMPERATURE ALONG THE ESCARPMENT. THESE FACTORS YIELD NEAR WARNING
CRITERIA FREEZING RAIN ALONG THE EAST FACING SLOPES...BUT LIGHT
AMOUNTS ELSEWHERE. I WILL KEEP THE WINTER WEATHER ADVISORY IN PLACE.
WINDS TONIGHT ACROSS THE MTN WILL BECOME QUITE STRONG...PRESSURE
GRADIENT ACROSS THE MTNS TIGHTENS TO AROUND 8 MBS BY 12Z. RIDGETOP
GUSTS SHOULD EXCEED 50 KTS...WITH WINDS BETWEEN 30 TO 40 KTS. THE
COMBINATION OF THE WINDS...WET GROUND...AND ICE ACCUMULATIONS MAY
YIELD TREE AND POWERLINE DAMAGE BY SUNRISE TUESDAY. I WILL UPDATE
THE NPW ALONG WITH THE HWO.
AS OF 630 PM...THE FORECAST APPEARS ON TRACK. I WILL UPDATE THE
T/TD/WINDS TO LATEST OBSERVATIONS.
AS OF 545 PM...I WILL UPDATE THE FORECAST THROUGH TUESDAY. LATEST
REGIONAL RADAR COMPOSITE INDICATES LITTLE TO NO RETURNS ACROSS THE
FORECAST AREA AND ACROSS THE UPSTREAM REGION. THEREFORE...I HAVE
SLOWED THE ARRIVAL OF CATE POPS UNTIL AFTER MIDNIGHT. THEN...ALL
SOLUTIONS INDICATE THAT WIDESPREAD PRECIP WILL OCCUR DURING THE PRE
DAWN HOURS AND EARLY DAYTIME HOURS ON TUESDAY...BEFORE A DRY SLOT
ARRIVES IN THE AFTERNOON.
THE SLOWING OF THE ARRIVAL OF POPS AND SLIGHT QPF FORECAST WILL HAVE
AN IMPACT ON THE ICE FORECAST LATE TONIGHT AND TUESDAY MORNING. THE
LATEST FORECAST WILL FEATURE VALUES APPROACHING 0.25 ALONG THE EAST
FACING SLOPES OF THE NC NRN MTNS...ELSEWHERE ACROSS THE ADJACENT
FOOTHILLS AND VALLEY...VALUES WILL REMAIN LESS THAN A TENTH OF AN
INCH. THE CURRENT WSW APPEARS WELL PLACED AND TIMED FOR ADVISORY
FREEZING RAIN. ONE NOTE...THE SREF GUIDANCE APPEARS VERY HIGH ON
FZRA AMOUNTS. THEREFORE...THE SREF PLUMES AND ANY GUIDANCE BASED ON
THE SREF WILL NOT BE CONSIDERED.
&&
.SHORT TERM /TONIGHT THROUGH THURSDAY/...
AS OF 230 PM EST MONDAY...THE SHORT TERM PERIOD BEGINS WITH AN
OCCLUDED FRONT MOVING EASTWARD AWAY FROM THE AREA ALLOWING A DRY
SLOT TO CONTINUE TO SURGE ACROSS THE REGION. HENCE...IT APPEARS THAT
THE PRECIP THREAT WILL HAVE ENDED TUE EVENING. TIME SECTIONS
INDICATE THAT LOW LEVELS REMAIN RATHER MOIST...SO MOSTLY CLOUDY
CONDITIONS WILL ONLY GRADUALLY GIVE WAY TO PARTLY CLOUDY CONDITIONS
TUE NIGHT. THERE IS SOME MODEL QPF RESPONSE IN THE SW MOUNTAINS LATE
TUE NIGHT DUE TO UPSLOPE...SO WILL HAVE SOME CHC TYPE POPS THERE.
THERMAL PROFILES INDICATE THAT ANY PRECIP WOULD BE LIGHT SNOW
SHOWERS. AS AN INTENSE UPPER LOW TRACKS INTO THE EASTERN GREAT LAKES
ON WED...A SHORT WAVE RIDGE IS FORECAST TO BUILD ACROSS THE AREA
WHICH SHOULD PRODUCE MOSTLY CLEAR CONDITIONS AND NEAR NORMAL TEMPS
EAST OF THE MOUNTAINS ...ALSO DUE IN PART TO DOWNSLOPING WINDS.
MOISTURE/CLOUDS WILL INCREASE OVER THE MOUNTAINS BY LATE IN THE DAY
AS AN UPPER TROUGH APPROACHES. SOME SCT RAIN/SNOW SHOWERS MAY
DEVELOP BY LATE WED ALONG THE TENNESSEE BORDER COUNTIES. PROFILES
CONTINUE TO MOISTEN AND COOL OVER THE MOUNTAINS WED NIGHT WITH THE
WINDS TURING MORE NW. THIS COMBINATION ALONG WITH SOME UPPER AIR
SUPPORT IS EXPECTED TO PRODUCE NUMEROUS SNOW SHOWERS ACROSS THE
MOUNTAINS...ESPECIALLY IN THE FAVORED UPSLOPE AREAS. AT LEAST SCT NW
FLOW SNOW SHOWERS WILL CONTINUE THROUGH THU AS WINDS AND MOISTURE
REMAIN FAVORABLE...THOUGH COVERAGE IS EXPECTED TO DECREASE THROUGH
THE DAY THU. SNOW TOTALS OVER THE MOUNTAINS FOR WED NIGHT AND THU
SHOULD BE IN THE 1 TO 3 INCH RANGE. STAYED CLOSE TO THE METMOS FOR
TEMPS THROUGH WED NIGHT. FOR THU...USED OUR LOW LEVEL THICKNESS
SCHEME WHICH YIELDED TEMPS BELOW GMOS.
&&
.LONG TERM /THURSDAY NIGHT THROUGH MONDAY/...
AS OF 230 PM EST MONDAY...THE DEEP LOW PRESSURE SYSTEM OVER THE NE
U.S. ON FRI WILL MOVE OFFSHORE...BUT WITH ADDITIONAL PIECES OF
SHORTWAVE ENERGY MOVING SWD THROUGH THE CENTRAL AND ERN CONUS TO
MAINTAIN THE UPPER TROUGH OVER THE AREA. AT LOW LEVELS...ENOUGH
UPSTREAM MOISTURE WILL PERSIST IN THE COLD NW FLOW TO KEEP SCATTERED
UPSLOPE SNOW SHOWERS GOING ACROSS THE WRN NC MTNS THROUGH FRIDAY.
MEANWHILE...THE STRONGEST UPSTREAM SHORTWAVE WILL DIG OVER THE LOWER
MS RIVER VALLEY...WITH THIS FEATURE LIKELY CROSSING THE EXTREME
SOUTHERN APPALACHIANS AND ADJACENT FOOTHILLS AND PIEDMONT SOMETIME
ON SAT. THE ECMWF REMAINS THE MOST VIGOROUS WITH THIS WAVE...BRIEFLY
CLOSING IT OFF ON SAT...BUT THE GFS/CMC ARE ALSO EXHIBITING BETTER
TROUGHINESS AND MOISTURE WITH THE WAVE. EVEN THE LESS AMPLIFED
MODELS APPEAR TO HAVE A FAIRLY POTENT VORT LOBE CROSSING THE
REGION...AND 850 TO 500 MB LAPSE RATES UP TO 6.5 DEG C/KM MAY
SUPPORT ISOLD TO SCT SNOW SHOWERS EAST OF THE MTNS SAT. POPS HAVE
BEEN ADJUSTED UP SLIGHTLY FROM THE PREVIOUS FORECAST.
A RETURN TO NW FLOW UPSLOPE MOISTURE WILL YIELD ADDITIONAL LIGHT MTN
SNOW SHOWER ACCUMS INTO SUNDAY AS THE UPPER TROUGH AXIS BECOMES
REINFORCED BY ADDITIONAL SHORTWAVE ENERGY. BETTER DRYING SHOULD THEN
SET IN THROUGH MON AS HIGH PRESSURE BUILDS IN FROM THE WEST. WILL
CONTINUE TO FEATURE MINS 5 TO 10 DEGREES BELOW NORMAL...WITH MAXES
10 TO 15 DEGREES BELOW NORMAL...THROUGH THE PERIOD.
&&
.AVIATION /06Z TUESDAY THROUGH SATURDAY/...
AT KCLT...WINDS WILL REMAIN NE/LY IN MATURE WEDGE AND HAVE KEPT
PERIODIC LOW END GUSTS THROUGH 13Z. A GENERAL LOWERING OF CIGS WILL
OCCUR OVERNIGHT WITH IFR LIKELY AROUND DAYBREAK. LIGHT RAIN WILL
BECOME MORE MODERATE AND CONSTANT AROUND DAYBREAK AS WELL. THE WEDGE
WILL BREAK DOWN WITH TRIPLE POINT LOW TRACKING NE...SO EMBEDDED
CONVECTION AND TSTMS ARE PROBABLE AFT 18Z TO AROUND 20Z. A DRY SLOT
IS EXPECTED TO MAKE A PUSH TOWARD THE TERMINAL LATER IN THE
AFTERNOON...SO WILL ANTICIPATE IMPROVING CONDS TO MVFR BY 22Z AND
VFR BY 01Z.
ELSEWHERE...A GENERAL REDUCTION IN FLIGHT CATS FROM MVFR TO IFR IS
EXPECTED AT ALL TAF SITES OVERNIGHT. SOME LOW END NE GUSTS WILL
PERSIST ACROSS THE UPSTATE AS THE RAIN SHIELD BECOMES MORE MODERATE
AND WIDESPREAD. WITH THE TIGHT P/GRAD ACROSS THE MTNS...LLWS WILL BE
MAINTAINED IN THE KAVL TAF FOR A COUPLE HRS BEGINNING AT 15Z. THE
DRY SLOT WILL AFFECT THE WESTERN TAF SITES FIRST AND RETURN MVFR/VFR
CONDS AT ALL TERMINALS BY THE EARLY TO MIDDLE AFTERNOON...HOWEVER
KHKY MAY BE STUCK IN MFVR CIG WEDGE CONDS THROUGH THE EVENING.
OUTLOOK...DRY AIR ADV AND CLEARING SKIES WILL CONTINUE WED NIGHT
WITH VFR CONDS EXPECTED THROUGH THURSDAY EAST OF THE MOUNTAINS. SOME
POTENTIAL EXISTS FOR MVFR ACROSS THE NC MTNS WITH SNOW SHOWERS MID
TO LATE WEEK.
CONFIDENCE TABLE...
06-12Z 12-18Z 18-24Z 00-06Z
KCLT HIGH 84% HIGH 85% HIGH 86% HIGH 82%
KGSP HIGH 95% HIGH 84% HIGH 86% HIGH 80%
KAVL HIGH 91% HIGH 100% MED 76% HIGH 85%
KHKY HIGH 86% HIGH 90% HIGH 86% MED 76%
KGMU HIGH 95% HIGH 84% HIGH 84% HIGH 80%
KAND LOW 49% HIGH 96% HIGH 83% 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...WINTER WEATHER ADVISORY UNTIL 9 AM EST THIS MORNING FOR NCZ033-
048>050-052-053-064-065-501-503-505-507-509.
HIGH WIND WARNING UNTIL 6 PM EST THIS EVENING FOR NCZ033-
048>052-058-059.
WIND ADVISORY UNTIL 6 PM EST THIS EVENING FOR NCZ033-048>052-
058-059.
SC...NONE.
&&
$$
SYNOPSIS...CSH
NEAR TERM...SBK/WIMBERLEY
SHORT TERM...LG
LONG TERM...HG
AVIATION...SBK
AREA FORECAST DISCUSSION
NWS GREENVILLE-SPARTANBURG SC
110 AM EST TUE FEB 26 2013
.SYNOPSIS...
NORTH OF A DEVELOPING WARM FRONT...MOISTURE WILL SPREAD ATOP OUR
REGION FROM THE GULF OF MEXICO. STRONG LOW PRESSURE WILL DRIVE
A COLD FRONT ACROSS OUR AREA ON TUESDAY.
&&
.NEAR TERM /THROUGH TODAY/...
AS OF 200 AM...THE LATEST SFC ANALYSIS INDICATES TW TEMPS AT
FREEZING OR BELOW ACROSS THE ADV AREA AND EVEN OVER THE NRN
FOOTHILLS. WILL MONITOR THE SENSIBLE WX OVER THE NEXT FEW HRS AS THE
PRECIP SHIELD MAKES HEADWAY INTO THE FCST AREA. VERY LIGHT PRECIP
IS NOTED CURRENTLY AND EXPECT DBZ/S TO PICK UP TO AROUND 20/25
AROUND 08Z-09Z ACROSS THE NC MTNS. THE LATEST HRRR KEEPS DECENT
PRECIP ACROSS THE ADV AREA THROUGHOUT IT/S RUN...WHICH MAY LEND
SUPPORT FOR A POSSIBLE UPGRADE TO A WARNING FOR FZRA AS LONG AS LLVL
WAA DOESNT CATCH UP BY THEN. MADE MINOR TWEAKS TO THE GOING GRIDS
FOR T/TD AND WINDS...POP/WX GRIDS STILL LOOK GOOD.
REGIONAL RADAR INDICATED THAT THE SIGNIFICANT RAINFALL WAS LOCATED
ACROSS SOUTHERN AND WESTERN GA. LATEST MODEL RUNS HAVE TRENDED
SLOWER WITH THE ARRIVAL OF THE RA ACROSS THE WESTERN FA AROUND
MIDNIGHT. WIDESPREAD PRECIPITATION IS EXPECTED TO EXPAND ACROSS THE
ENTIRE CWA BY 9Z. FORECAST SOUNDINGS INDICATE THAT A DEEP WARM NOSE
WILL EXIST ACROSS THE REGION TONIGHT...WARMING ABOVE 4C AT 3 KFT BY
LATE TONIGHT. PRECIP THAT FALLS WILL BE EITHER RA OR FZRA...POSSIBLY
SOME IP AT TIMES.
OBSERVATIONS AT 10 PM INDICATE THAT NRN MTNS RANGE FROM THE MID 30S
TO U20S. HOWEVER...TEMPERATURES MAY BECOME STEADY OR GRADUALLY RISE
WITH THE ARRIVAL OF WAA AND LOWER CLOUD COVER. IN ADDITION...LLVL
FLOW...PRECIP...DEEPENING MOISTURE SHOULD RESULT IN A GRADUAL
WARMING OF DEWPOINTS OVERNIGHT. BASED ON THE MARGINAL
TEMPERATURES...FREEZING RAIN SHOULD REMAIN LIMITED TO THE EAST
FACING SLOPES OF THE MTNS FROM HENDERSON TO AVERY...ALONG WITH THE
ADJACENT FOOTHILLS. IN ADDITION...UPSLOPE FLOW MAY AID IN COOLING
TEMPERATURE ALONG THE ESCARPMENT. THESE FACTORS YIELD NEAR WARNING
CRITERIA FREEZING RAIN ALONG THE EAST FACING SLOPES...BUT LIGHT
AMOUNTS ELSEWHERE. I WILL KEEP THE WINTER WEATHER ADVISORY IN PLACE.
WINDS TONIGHT ACROSS THE MTN WILL BECOME QUITE STRONG...PRESSURE
GRADIENT ACROSS THE MTNS TIGHTENS TO AROUND 8 MBS BY 12Z. RIDGETOP
GUSTS SHOULD EXCEED 50 KTS...WITH WINDS BETWEEN 30 TO 40 KTS. THE
COMBINATION OF THE WINDS...WET GROUND...AND ICE ACCUMULATIONS MAY
YIELD TREE AND POWERLINE DAMAGE BY SUNRISE TUESDAY. I WILL UPDATE
THE NPW ALONG WITH THE HWO.
AS OF 630 PM...THE FORECAST APPEARS ON TRACK. I WILL UPDATE THE
T/TD/WINDS TO LATEST OBSERVATIONS.
AS OF 545 PM...I WILL UPDATE THE FORECAST THROUGH TUESDAY. LATEST
REGIONAL RADAR COMPOSITE INDICATES LITTLE TO NO RETURNS ACROSS THE
FORECAST AREA AND ACROSS THE UPSTREAM REGION. THEREFORE...I HAVE
SLOWED THE ARRIVAL OF CATE POPS UNTIL AFTER MIDNIGHT. THEN...ALL
SOLUTIONS INDICATE THAT WIDESPREAD PRECIP WILL OCCUR DURING THE PRE
DAWN HOURS AND EARLY DAYTIME HOURS ON TUESDAY...BEFORE A DRY SLOT
ARRIVES IN THE AFTERNOON.
THE SLOWING OF THE ARRIVAL OF POPS AND SLIGHT QPF FORECAST WILL HAVE
AN IMPACT ON THE ICE FORECAST LATE TONIGHT AND TUESDAY MORNING. THE
LATEST FORECAST WILL FEATURE VALUES APPROACHING 0.25 ALONG THE EAST
FACING SLOPES OF THE NC NRN MTNS...ELSEWHERE ACROSS THE ADJACENT
FOOTHILLS AND VALLEY...VALUES WILL REMAIN LESS THAN A TENTH OF AN
INCH. THE CURRENT WSW APPEARS WELL PLACED AND TIMED FOR ADVISORY
FREEZING RAIN. ONE NOTE...THE SREF GUIDANCE APPEARS VERY HIGH ON
FZRA AMOUNTS. THEREFORE...THE SREF PLUMES AND ANY GUIDANCE BASED ON
THE SREF WILL NOT BE CONSIDERED.
&&
.SHORT TERM /TONIGHT THROUGH THURSDAY/...
AS OF 230 PM EST MONDAY...THE SHORT TERM PERIOD BEGINS WITH AN
OCCLUDED FRONT MOVING EASTWARD AWAY FROM THE AREA ALLOWING A DRY
SLOT TO CONTINUE TO SURGE ACROSS THE REGION. HENCE...IT APPEARS THAT
THE PRECIP THREAT WILL HAVE ENDED TUE EVENING. TIME SECTIONS
INDICATE THAT LOW LEVELS REMAIN RATHER MOIST...SO MOSTLY CLOUDY
CONDITIONS WILL ONLY GRADUALLY GIVE WAY TO PARTLY CLOUDY CONDITIONS
TUE NIGHT. THERE IS SOME MODEL QPF RESPONSE IN THE SW MOUNTAINS LATE
TUE NIGHT DUE TO UPSLOPE...SO WILL HAVE SOME CHC TYPE POPS THERE.
THERMAL PROFILES INDICATE THAT ANY PRECIP WOULD BE LIGHT SNOW
SHOWERS. AS AN INTENSE UPPER LOW TRACKS INTO THE EASTERN GREAT LAKES
ON WED...A SHORT WAVE RIDGE IS FORECAST TO BUILD ACROSS THE AREA
WHICH SHOULD PRODUCE MOSTLY CLEAR CONDITIONS AND NEAR NORMAL TEMPS
EAST OF THE MOUNTAINS ...ALSO DUE IN PART TO DOWNSLOPING WINDS.
MOISTURE/CLOUDS WILL INCREASE OVER THE MOUNTAINS BY LATE IN THE DAY
AS AN UPPER TROUGH APPROACHES. SOME SCT RAIN/SNOW SHOWERS MAY
DEVELOP BY LATE WED ALONG THE TENNESSEE BORDER COUNTIES. PROFILES
CONTINUE TO MOISTEN AND COOL OVER THE MOUNTAINS WED NIGHT WITH THE
WINDS TURING MORE NW. THIS COMBINATION ALONG WITH SOME UPPER AIR
SUPPORT IS EXPECTED TO PRODUCE NUMEROUS SNOW SHOWERS ACROSS THE
MOUNTAINS...ESPECIALLY IN THE FAVORED UPSLOPE AREAS. AT LEAST SCT NW
FLOW SNOW SHOWERS WILL CONTINUE THROUGH THU AS WINDS AND MOISTURE
REMAIN FAVORABLE...THOUGH COVERAGE IS EXPECTED TO DECREASE THROUGH
THE DAY THU. SNOW TOTALS OVER THE MOUNTAINS FOR WED NIGHT AND THU
SHOULD BE IN THE 1 TO 3 INCH RANGE. STAYED CLOSE TO THE METMOS FOR
TEMPS THROUGH WED NIGHT. FOR THU...USED OUR LOW LEVEL THICKNESS
SCHEME WHICH YIELDED TEMPS BELOW GMOS.
&&
.LONG TERM /THURSDAY NIGHT THROUGH MONDAY/...
AS OF 230 PM EST MONDAY...THE DEEP LOW PRESSURE SYSTEM OVER THE NE
U.S. ON FRI WILL MOVE OFFSHORE...BUT WITH ADDITIONAL PIECES OF
SHORTWAVE ENERGY MOVING SWD THROUGH THE CENTRAL AND ERN CONUS TO
MAINTAIN THE UPPER TROUGH OVER THE AREA. AT LOW LEVELS...ENOUGH
UPSTREAM MOISTURE WILL PERSIST IN THE COLD NW FLOW TO KEEP SCATTERED
UPSLOPE SNOW SHOWERS GOING ACROSS THE WRN NC MTNS THROUGH FRIDAY.
MEANWHILE...THE STRONGEST UPSTREAM SHORTWAVE WILL DIG OVER THE LOWER
MS RIVER VALLEY...WITH THIS FEATURE LIKELY CROSSING THE EXTREME
SOUTHERN APPALACHIANS AND ADJACENT FOOTHILLS AND PIEDMONT SOMETIME
ON SAT. THE ECMWF REMAINS THE MOST VIGOROUS WITH THIS WAVE...BRIEFLY
CLOSING IT OFF ON SAT...BUT THE GFS/CMC ARE ALSO EXHIBITING BETTER
TROUGHINESS AND MOISTURE WITH THE WAVE. EVEN THE LESS AMPLIFED
MODELS APPEAR TO HAVE A FAIRLY POTENT VORT LOBE CROSSING THE
REGION...AND 850 TO 500 MB LAPSE RATES UP TO 6.5 DEG C/KM MAY
SUPPORT ISOLD TO SCT SNOW SHOWERS EAST OF THE MTNS SAT. POPS HAVE
BEEN ADJUSTED UP SLIGHTLY FROM THE PREVIOUS FORECAST.
A RETURN TO NW FLOW UPSLOPE MOISTURE WILL YIELD ADDITIONAL LIGHT MTN
SNOW SHOWER ACCUMS INTO SUNDAY AS THE UPPER TROUGH AXIS BECOMES
REINFORCED BY ADDITIONAL SHORTWAVE ENERGY. BETTER DRYING SHOULD THEN
SET IN THROUGH MON AS HIGH PRESSURE BUILDS IN FROM THE WEST. WILL
CONTINUE TO FEATURE MINS 5 TO 10 DEGREES BELOW NORMAL...WITH MAXES
10 TO 15 DEGREES BELOW NORMAL...THROUGH THE PERIOD.
&&
.AVIATION /06Z TUESDAY THROUGH SATURDAY/...
AT KCLT...WINDS WILL REMAIN NE/LY IN MATURE WEDGE AND HAVE KEPT
PERIODIC LOW END GUSTS THROUGH 13Z. A GENERAL LOWERING OF CIGS WILL
OCCUR OVERNIGHT WITH IFR LIKELY AROUND DAYBREAK. LIGHT RAIN WILL
BECOME MORE MODERATE AND CONSTANT AROUND DAYBREAK AS WELL. THE WEDGE
WILL BREAK DOWN WITH TRIPLE POINT LOW TRACKING NE...SO EMBEDDED
CONVECTION AND TSTMS ARE PROBABLE AFT 18Z TO AROUND 20Z. A DRY SLOT
IS EXPECTED TO MAKE A PUSH TOWARD THE TERMINAL LATER IN THE
AFTERNOON...SO WILL ANTICIPATE IMPROVING CONDS TO MVFR BY 22Z AND
VFR BY 01Z.
ELSEWHERE...A GENERAL REDUCTION IN FLIGHT CATS FROM MVFR TO IFR IS
EXPECTED AT ALL TAF SITES OVERNIGHT. SOME LOW END NE GUSTS WILL
PERSIST ACROSS THE UPSTATE AS THE RAIN SHIELD BECOMES MORE MODERATE
AND WIDESPREAD. WITH THE TIGHT P/GRAD ACROSS THE MTNS...LLWS WILL BE
MAINTAINED IN THE KAVL TAF FOR A COUPLE HRS BEGINNING AT 15Z. THE
DRY SLOT WILL AFFECT THE WESTERN TAF SITES FIRST AND RETURN MVFR/VFR
CONDS AT ALL TERMINALS BY THE EARLY TO MIDDLE AFTERNOON...HOWEVER
KHKY MAY BE STUCK IN MFVR CIG WEDGE CONDS THROUGH THE EVENING.
OUTLOOK...DRY AIR ADV AND CLEARING SKIES WILL CONTINUE WED NIGHT
WITH VFR CONDS EXPECTED THROUGH THURSDAY EAST OF THE MOUNTAINS. SOME
POTENTIAL EXISTS FOR MVFR ACROSS THE NC MTNS WITH SNOW SHOWERS MID
TO LATE WEEK.
CONFIDENCE TABLE...
06-12Z 12-18Z 18-24Z 00-06Z
KCLT HIGH 84% HIGH 85% HIGH 86% HIGH 82%
KGSP HIGH 95% HIGH 84% HIGH 86% HIGH 80%
KAVL HIGH 91% HIGH 100% MED 76% HIGH 85%
KHKY HIGH 86% HIGH 90% HIGH 86% MED 76%
KGMU HIGH 95% HIGH 84% HIGH 84% HIGH 80%
KAND LOW 49% HIGH 96% HIGH 83% 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...WINTER WEATHER ADVISORY UNTIL 9 AM EST THIS MORNING FOR NCZ033-
048>050-052-053-064-065-501-503-505-507-509.
HIGH WIND WARNING UNTIL 6 PM EST THIS EVENING FOR NCZ033-
048>052-058-059.
WIND ADVISORY UNTIL 6 PM EST THIS EVENING FOR NCZ033-048>052-
058-059.
SC...NONE.
&&
$$
SYNOPSIS...CSH
NEAR TERM...SBK/WIMBERLEY
SHORT TERM...LG
LONG TERM...HG
AVIATION...SBK
AREA FORECAST DISCUSSION...UPDATED
NWS FORT WORTH TX
1107 PM CST MON FEB 25 2013
.AVIATION...
STRONG WEST/NORTHWEST WINDS CONTINUE ACROSS THE AREA. CURRENT
SPEEDS ARE SUSTAINED AROUND 25 KNOTS WITH GUSTS AROUND 35 KNOTS
AND THINK THESE SPEEDS WILL HOLD FOR MOST OF THE NIGHT. DIRECTION
IS STEADY...AROUND 300 DEGREES. WINDS SHOULD VEER A BIT BY MORNING
WITH SPEEDS SLOWLY DECREASING AFTER SUNRISE. BY SUNSET
TOMORROW...GRADIENT WILL FINALLY SLACKEN AND SPEEDS WILL DROP
BELOW 10 KNOTS.
MVFR CIGS ARE IN PLACE ACROSS THE METROPLEX WITH BASES AROUND
2KFT. FOR WACO...VFR CIGS ARE CURRENTLY PREVAILING AND WILL KEEP
THE CIGS AT 3.5KFT. COULD SEE MVFR OVERNIGHT...BUT CONFIDENCE
WASNT HIGH ENOUGH TO MENTION AT THIS TIME. CIGS SHOULD SCATTER
ACROSS THE AREA AROUND SUNRISE...WHEN DRIER AIR FILTERS INTO THE
REGION.
HAMPSHIRE
&&
.UPDATE...
PREVIOUS FRONTOGENETICAL SNOW BAND THAT MOVED THROUGH MONTAGUE
COUNTY AN HOUR OR SO AGO HAS WEAKENED CONSIDERABLY...AS RETURNS
VIA CLEAR AIR MODE ON RADAR AND DUAL POL PRODUCTS INDICATE. HIGH-
RES RAP AND WRF MODELS ALSO INDICATE THIS TREND...AS ISENTROPIC
DOWNGLIDE AND SUBSIDENCE CONTINUE TO WEAKEN RETURNS ACROSS NORTH
TEXAS IN WAKE OF THE MID LEVEL LOW MOVING INTO SOUTHEAST OKLAHOMA
THIS EVENING. MODEL SOUNDINGS DO INDICATE THE TOP-DOWN DRYING OF
THE COLUMN BY MID EVENING INDICATIVE OF SUBSIDENCE WITH DENDRITE
SEEDING FROM THE MID AND UPPER LEVELS NO LONGER AVAILABLE.
WE DID LEAVE LOW CHANCES OF A VERY LIGHT RAIN/SNOW MIX OR A MENTION
OF SPRINKLES OR FLURRIES WITH ONLY SHALLOW MOISTURE BEING LEFT
OVER THROUGH THE OVERNIGHT. WE ARE CANCELING THE WINTER WEATHER
ADVISORY FOR OUR NORTHWEST COUNTIES...BUT MAINTAINING THE WIND
ADVISORY OVERNIGHT WITH STRONG COLD ADVECTION AND A TIGHT WNW
PRESSURE GRADIENT MAINTAINING THROUGH THE NIGHT. THE PERSISTENT
LINGERING WRAP-AROUND STRATUS WILL KEEP MOST AREAS FROM REACHING
FREEZING BY TUESDAY MORNING. WNW WINDS 25-35 WITH GUSTS TO 40-45
WILL CONTINUE INTO THE EARLY MORNING HOURS TUESDAY.
05/
&&
.PREV DISCUSSION... /ISSUED 350 PM CST MON FEB 25 2013/
POWERFUL WINTER STORM CONTINUES TO MOVE THROUGH THE SOUTHERN
PLAINS THIS AFTERNOON RESULTING IN PRIMARILY A WIND EVENT ACROSS
NORTH TEXAS...BUT SOME WINTRY WEATHER IS EXPECTED THROUGH THIS
EVENING FOR PARTS OF THE AREA. LATEST SURFACE ANALYSIS SHOWS THE
CENTER OF THE SURFACE LOW NEAR EL DORADO ARKANSAS WHERE 3 HOUR
PRESSURE FALLS ARE IN EXCESS OF 7MB. PRESSURE FALLS EXTEND ALL THE
WAY WESTWARD TOWARD WICHITA FALLS WHERE A SURFACE TROUGH HAS
PERSISTED ALL DAY. THESE PERSISTENT PRESSURE FALLS ARE AN
INDICATION THAT THE ENTIRE UPPER STORM SYSTEM IS DEEPENING. WATER
VAPOR IMAGERY SHOWS A WELL DEFINED CIRCULATION WHICH APPEARS TO
NOW BE MOVING DUE EAST TOWARD THE BEST SURFACE PRESSURE FALLS.
THIS IS CONCERNING BECAUSE SUBSTANTIAL WRAP AROUND PRECIPITATION
DRIVEN BY FRONTOGENETICAL FORCING WILL LIKELY TRACK FARTHER SOUTH
THAN EARLIER ANTICIPATED. SHORT TERM HIGH RESOLUTION GUIDANCE
APPEARS TO HAVE SOMEWHAT OF A HANDLE ON THE MOVEMENT OF THE UPPER
SYSTEM BUT PRECIPITATION IS QUICKLY ERODED DUE TO STRONG
SUBSIDENCE. MESOSCALE FRONTOGENETICAL FORCING IS LIKELY TO WIN OUT
AT LEAST FOR A FEW HOURS ON THE BACK SIDE OF THE SYSTEM RESULTING
IN PRECIPITATION ACROSS MAINLY THE NORTHWEST COUNTIES THROUGH MIDNIGHT.
CONCERNING THE PRECIPITATION...FORECAST SOUNDINGS FROM BOTH THE
HIGH RES 3KM TTU WRF AND RAP MODEL SUGGEST THAT THE THERMAL
PROFILE WILL BE SUFFICIENTLY COLD FOR SNOWFALL PRODUCTION
GENERALLY NORTH OF INTERSTATE 20 THROUGH LATE TONIGHT...DESPITE
THE WARM SURFACE TEMPERATURES. INITIAL CONVECTIVE SHOWERS
NORTHEAST OF THE METROPLEX SHOULD REMAIN ALL LIQUID. GIVEN THE
POTENTIAL FOR SNOWFALL...ALONG WITH STRONG GUSTY WINDS...HAVE
ISSUED A SHORT DURATION WINTER WEATHER ADVISORY FOR THE FAR
NORTHWEST COUNTIES THROUGH MIDNIGHT. WITH WARM GROUND TEMPERATURES
AND GENERALLY ABOVE FREEZING SURFACE TEMPERATURES...EXPECT ANY
ACCUMULATIONS TO BE CONFINED TO GRASSY SURFACES. THE PRIMARY
CONCERN WILL BE FOR BLOWING SNOW WHICH COULD REDUCE VISIBILITY TO
LESS THAN 1/2 MILE AT TIMES. ROADS SHOULD REMAIN IN GOOD SHAPE.
THE OTHER MAIN CONCERN IS WINDS THROUGH LATE TONIGHT. WITH THE
CENTER OF THE SURFACE LOW NEARBY FOR MUCH OF THE AFTERNOON...WINDS
HAVE GENERALLY BEEN HIGHEST ACROSS THE SOUTHERN COUNTIES WHERE
GUSTS TO 54 MPH HAVE BEEN REPORTED. WITH THE SURFACE LOW NOW
MOVING EAST...THE PRESSURE GRADIENT WILL CONTINUE TO TIGHTEN
THROUGH EVENING. THE STRONGEST LOW LEVEL JET WILL BE CENTERED
ACROSS THE AREA RIGHT AROUND MIDNIGHT SO IT APPEARS THAT THE
STRONGEST WINDS ACROSS MUCH OF THE REGION ARE STILL TO COME.
ONE LIMITING FACTOR TO STRONGER WINDS WILL BE THE FACT THAT IT
WILL BE NIGHT WHEN THE STRONGEST WINDS ALOFT ARE OVERHEAD. THE CURRENT
WIND ADVISORY WILL REMAIN IN EFFECT THROUGH 4 AM FOR ALL OF NORTH
TEXAS.
WITH THE ENTIRE SYSTEM MOVING TO THE NORTHEAST TOMORROW...SKIES
SHOULD CLEAR AND WINDS WILL DIMINISH. A COUPLE OF REINFORCING
FRONTS...ONE ON WEDNESDAY AND ANOTHER LATE THURSDAY NIGHT...WILL
KEEP TEMPERATURES COOL THROUGH THE WEEK. NO SIGNIFICANT CHANGES TO
THE EXTENDED FORECAST AS IT APPEARS THAT IT WILL REMAIN DRY
THROUGH THE PERIOD.
DUNN
&&
.PRELIMINARY POINT TEMPS/POPS...
DALLAS-FT. WORTH, TX 36 54 34 54 34 / 20 5 0 0 5
WACO, TX 37 61 34 60 33 / 5 0 0 0 5
PARIS, TX 36 49 31 51 31 / 30 5 0 0 5
DENTON, TX 36 53 30 51 31 / 30 5 0 0 5
MCKINNEY, TX 36 52 32 51 32 / 20 5 0 0 5
DALLAS, TX 37 56 35 55 35 / 20 5 0 0 5
TERRELL, TX 37 52 34 54 34 / 10 5 0 0 5
CORSICANA, TX 38 57 35 58 34 / 5 0 0 0 5
TEMPLE, TX 37 63 36 63 33 / 5 0 0 0 5
MINERAL WELLS, TX 34 57 30 54 29 / 30 0 0 0 5
&&
.FWD WATCHES/WARNINGS/ADVISORIES...
WIND ADVISORY UNTIL 4 AM CST TUESDAY FOR TXZ091>095-100>107-
115>123-129>135-141>148-156>162-174-175.
&&
$$
/
AREA FORECAST DISCUSSION
NWS GRAND JUNCTION CO
813 AM MST TUE FEB 26 2013
.UPDATE...
ISSUED AT 813 AM MST TUE FEB 26 2013
IMPACT BASED ADVISORIES HAVE BEEN ISSUED FOR SEVERAL OF THE LOWER
VALLEYS THIS MORNING AS LIGHT SNOW CONTINUES TO HAMPER THE MORNING
COMMUTE. SNOW WILL BECOME MORE SCATTERED IN NATURE THIS THIS
AFTERNOON...BUT CONVECTIVE ELEMENT WILL ENHANCE
SHOWERS...RESULTING IN LOCALIZED HEAVY SNOWFALL. SO HAVE CARRIED
THE VALLEY HIGHLIGHTS THROUGH LATE THIS AFTERNOON AND EVENING
BASED ON LOCATION. IN ADDITION...AREA OF CONVERGENCE SETTING UP
ACROSS THE SAN JUANS AND LIGHT SNOW CONTINUES TO DRAG SOUTH INTO
THE NORTHWEST SAN JUANS. BANDING PRECIP ALONG THE UNCOMPAHGRE
PLATEAU SHIFTS SLOWLY SOUTH AND WILL PROVIDE ADDITIONAL SNOWFALL
THROUGH LATE THIS MORNING. LIGHT NORTHERLY COMPONENT TO BOUNDARY
LAYER WINDS WILL KEEP DRIVING MOISTURE INTO THE GORGE SOUTH OF
OURAY...RESULTING IN LOCALLY HEAVY SNOWFALL. AMOUNTS MAY EXCEED 6
INCHES IN THIS AREA AND LOW END ADVISORY APPEARS JUSTIFIED. PRECIP
WINDS DOWN LATER THIS AFTERNOON AND OVERNIGHT FROM SOUTHWEST TO
NORTHWEST AS THE MAIN UPPER LEVEL LOW LIFTS OUT INTO THE PLAINS.
ZONES HAVE BEEN UPDATED WITH NEW SNOW TOTALS AND POPS.
UPDATE ISSUED AT 621 AM MST TUE FEB 26 2013
GRID UPDATE TO BOOST POPS WITH WIDESPREAD SNOW OCCURRING BENEATH
THE ENHANCED CLOUD OVER NW AND WEST CENTRAL COLORADO. TROUGH AXIS
IS OVER ERN UTAH AT 13Z...BUT UPPER CIRCULATION IS PROGGED BY THE
13KM RAP MODEL TO BE CENTERED OVER THE NWRN SAN JUAN MOUNTAINS BY
EARLY AFTERNOON. THIS AREA WILL NEED TO BE MONITORED AS NORTHWEST
FLOW AND NEGATIVE EQUIVALENT POTENTIAL VORTICITY SUGGEST BANDS OF
SNOW MAY BE TRAINING INTO THE GORGE. CURRENTLY ON THE RADAR...ONE
BAND OF SNOW IS TRYING TO BECOME ESTABLISHED ALONG THE UNCOMPAHGRE
PLATEAU. A WINTER WEATHER ADVISORY MAY BE NEEDED FOR ZONE 18.
REMAINDER OF THE FORECAST AREA APPEARS ON TRACK WITH SNOW BEGINNING
TO SPREAD OVER THE ELK MOUNTAINS TOWARD THE GORE RANGE.
&&
.SHORT TERM...(TODAY THROUGH WEDNESDAY)
ISSUED AT 355 AM MST TUE FEB 26 2013
THE NEXT WEATHER MAKER IN THE FORM OF AN OPEN TROUGH HAS BEGUN TO
MOVE INTO THE AREA EARLY THIS MORNING. CLOUDS HAVE INCREASED AND
LOWERED AHEAD OF THIS WAVE...WITH RADAR ECHOES REFLECTING THIS
TREND. ALSO SINCE AROUND 1 AM MST...K3MW IN THE PARK RANGE HAS
REPORTED SNOW...AND EXPECT SHOWERS HAVE DEVELOPED AT OTHER
NORTHERN MOUNTAIN LOCATIONS AS WELL.
THE LOW CENTER WILL DROP FROM THE NORTHERN ROCKIES SOUTH-SOUTHEAST
ACROSS WY BY MID-MORNING...AND OVER NORTHWEST CO BY MIDDAY. ALSO A
NOT VERY DISTINCT SURFACE FRONT AHEAD OF THE UPPER LEVEL TROUGH
WILL SEEP OVER THE AREA FROM NORTHWEST TO SOUTHEAST EARLY TODAY.
AS A RESULT SNOW WILL CONTINUE TO SPREAD IN FROM THE NORTHWEST
THROUGH THE NEXT 3-12 HOURS. BY DAYLIGHT...SNOW SHOULD BE
WIDESPREAD ACROSS THE NORTHERN MOUNTAINS AND WILL FILL INTO THE
WEST-CENTRAL CO MOUNTAINS BY MID MORNING. SNOW WILL CONTINUE
THROUGH THE AFTERNOON AS THE -32/-33 COLD POOL AT 500 MB MOVES
OVER THE AREA. THE PRESENT FORECAST LOOKS ON TRACK WITH LOW-END
ADVISORY AMOUNTS IN THE NORTHERN AND WEST-CENTRAL MOUNTAINS...
FAVORING THE NORTHWEST FACING SLOPES. OTHER MOUNTAIN AREAS SHOULD
SEE A PERIOD OF SNOW...BUT WITH LIGHTER ACCUMULATIONS. VALLEYS
WILL SEE ISOLATED TO SCATTERED SNOW SHOWERS...WITH BETTER COVERAGE
OVER MUCH OF THE NORTH...AND LITTLE TO NO SHOWERS ALONG OUR WEST
AND SOUTHWEST BORDERS. BY LATE AFTERNOON ACTIVITY WILL BEGIN TO
DIMINISH IN THE WESTERN VALLEYS AS DRIER AIR MOVES IN. HOWEVER
SNOW WILL CONTINUE IN THE CO MOUNTAINS THROUGH THE EVENING THE AS
THE COLD AIR ALOFT REMAINS IN PLACE...AND THE FAVORED DENDRITIC
GROWTH LAYER WILL REMAIN SATURATED AND NEAR MOUNTAIN TOP LEVEL.
THEN BY LATE TONIGHT THE NORTH FLOW WILL CONTINUE TO PRODUCE LIGHT
SNOW ALONG THE NORTH SLOPES OF THOSE FAVORED NORTH AND CENTRAL
MOUNTAINS. THIS ACTIVITY WILL GRADUALLY DIMINISH TOWARDS SUNRISE
WED.
ONE AREA THAT SHOULD BE WATCHED IS THE UNCOMPAHGRE GORGE AT AND
NEAR OURAY CO. THIS AREA COULD PICK UP SOME DECENT ACCUMULATIONS
AS THE FLOW TURNS AROUND TO NORTH LATER TODAY THROUGH THIS
EVENING. HOWEVER...I CHOSE NOT TO INCLUDE CO ZONE 18 IN THE
ADVISORY AS THE DURATION WILL BE SHORT...AND THE HEAVIER
ACCUMULATIONS ARE EXPECTED TO BE LOCALIZED.
ANY REMAINING SHOWERS IN THE NORTHERN MOUNTAINS WILL QUICKLY WIND
DOWN THROUGH THE MORNING ON WED...WITH ONLY A FEW LINGERING BEYOND
MIDDAY NEAR THE CONTINENTAL DIVIDE.
BELOW NORMAL TEMPERATURES WILL CONTINUE.
.LONG TERM...(WEDNESDAY NIGHT THROUGH MONDAY)
ISSUED AT 355 AM MST TUE FEB 26 2013
RIDGE AMPLIFIES OVER THE WEST COAST STATES WEDNESDAY NIGHT INTO
THURSDAY NIGHT...BUT THE GFS AND TO A LESSER EXTENT THE SREF
INDICATE A DISTURBANCE WILL STREAM OVER THE NRN DIVIDE MOUNTAINS FOR
A CHANCE OF SNOW. THE ECMWF APPEARS TO BE TRENDING THIS DIRECTION
SO THE CHANCE POPS APPEAR WARRANTED. THIS WOULD BE A FAST MOVING
DISTURBANCE AND ANY SNOWFALL WILL BE LIGHT.
IN THE BIGGER PICTURE...A WARMING TREND WILL OCCUR THIS UPCOMING
WEEKEND AS A WARM RIDGE MOVES EAST ACROSS THE INTERMOUNTAIN WEST AND
ROCKY MOUNTAIN STATES ON SATURDAY AND SUNDAY. EXPECT WARMING TEMPS
AT ALL LOCATIONS...OR SLIGHTLY ABOVE AVERAGE COMPARED TO CLIMO.
RECENT TEMPS HAVE BEEN BELOW NORMAL...SO THIS WARMING WILL FEEL MORE
SIGNIFICANT THAN COMPARED TO CLIMO.
FORECAST CONFIDENCE DIMINISHES SUNDAY NIGHT AND MONDAY AS A
SIGNIFICANT SHORT WAVE PUNCHES ACROSS THE PACIFIC NORTHWEST AND NRN
INTERMOUNTAIN REGION. SOME ENTRAINMENT OF SUBTROPICAL MOISTURE IS
POSSIBLE AHEAD OF THIS FEATURE...AND THIS COULD LEAD TO CHANCE OF
PRECIPITATION SUNDAY NIGHT. MONDAY BECOMES MORE MURKY AS THE ECMWF
SHOWS MUCH COLDER AIR SPILLING INTO THE FORECAST AREA. WOULD LIKE
TO SEE SOME CONFIRMATION BY THE GFS OR RUN TO RUN CONTINUITY BY THE
EURO MODEL. WILL NOT MAKE TOO MANY CHANGES FROM THE CONSENSUS
OUTPUT...BUT DID LOWER MAX TEMPS ACROSS THE NWRN COLORADO VALLEYS.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z WEDNESDAY MORNING)
ISSUED AT 355 AM MST TUE FEB 26 2013
SNOW OVER THE NORTHERN AND CENTRAL MOUNTAINS EARLY THIS MORNING
WILL SPREAD INTO THE SOUTHERN MOUNTAINS BY AROUND 14Z...AND THEN
QUICKLY BECOME WIDESPREAD.
AN UPPER LEVEL TROUGH WILL PASS OVER THE AREA FROM 12Z/TUE TO
00Z/WED. AS A RESULT...AIRFIELDS WILL LIKELY SEE PERIODS OF MVFR
CIGS AND VSBY WITH BRIEF IFR CONDITIONS POSSIBLE IN HEAVIER
SHOWERS. PERSISTENT MOIST NORTHWESTERLY FLOW WILL FAVOR PROLONGED
PERIODS OF SNOW AT AIRPORTS EAST OF A 2OW KCAG-KMTJ LINE DURING
THE AFTERNOON. IN CONTRAST...NORTHWEST WINDS ARE UNFAVORABLE FOR
THE SOUTHERN AIRPORTS...SPECIFICALLY KCEZ...KDRO AND KPSO WHICH
WILL EXPERIENCE DRY DOWNSLOPE FLOW THROUGHOUT THE DAY. THE
MOUNTAINS WILL BE OBSCURED THROUGH 06Z WITH GUSTY NORTHWEST WINDS
AT TIMES RESULTING IN MECHANICAL TURBULENCE IN THE LEE OF PEAKS
AND RIDGES. MOUNTAIN SNOW WILL DIMINISH AFTER 06Z...BUT SNOW
SHOWERS WILL CONTINUE ALONG NORTHWEST-NORTH FACING SLOPES OF THE
NORTH AND WEST-CENTRAL COLORADO MOUNTAINS. THEREFORE MOUNTAIN
OBSCURATIONS WILL CONTINUE ALONG THESE SLOPES.
&&
.GJT WATCHES/WARNINGS/ADVISORIES...
CO...WINTER WEATHER ADVISORY UNTIL 9 PM MST THIS EVENING FOR COZ012-
017-018.
WINTER WEATHER ADVISORY UNTIL 9 AM MST WEDNESDAY FOR COZ004-009-
010-013.
WINTER WEATHER ADVISORY UNTIL MIDNIGHT MST TONIGHT FOR COZ007-
008.
WINTER WEATHER ADVISORY UNTIL 6 PM MST THIS EVENING FOR COZ011-
014.
UT...NONE.
&&
$$
UPDATE...JDC
SHORT TERM...EH
LONG TERM...PF
AVIATION...EH
AREA FORECAST DISCUSSION
NWS GRAND JUNCTION CO
621 AM MST TUE FEB 26 2013
.UPDATE...
ISSUED AT 621 AM MST TUE FEB 26 2013
GRID UPDATE TO BOOST POPS WITH WIDESPREAD SNOW OCCURRING BENEATH
THE ENHANCED CLOUD OVER NW AND WEST CENTRAL COLORADO. TROUGH AXIS
IS OVER ERN UTAH AT 13Z...BUT UPPER CIRCULATION IS PROGGED BY THE
13KM RAP MODEL TO BE CENTERED OVER THE NWRN SAN JUAN MOUNTAINS BY
EARLY AFTERNOON. THIS AREA WILL NEED TO BE MONITORED AS NORTHWEST
FLOW AND NEGATIVE EQUIVALENT POTENTIAL VORTICITY SUGGEST BANDS OF
SNOW MAY BE TRAINING INTO THE GORGE. CURRENTLY ON THE RADAR...ONE
BAND OF SNOW IS TRYING TO BECOME ESTABLISHED ALONG THE UNCOMPAHGRE
PLATEAU. A WINTER WEATHER ADVISORY MAY BE NEEDED FOR ZONE 18.
REMAINDER OF THE FORECAST AREA APPEARS ON TRACK WITH SNOW BEGINNING
TO SPREAD OVER THE ELK MOUNTAINS TOWARD THE GORE RANGE.
&&
.SHORT TERM...(TODAY THROUGH WEDNESDAY)
ISSUED AT 355 AM MST TUE FEB 26 2013
THE NEXT WEATHER MAKER IN THE FORM OF AN OPEN TROUGH HAS BEGUN TO
MOVE INTO THE AREA EARLY THIS MORNING. CLOUDS HAVE INCREASED AND
LOWERED AHEAD OF THIS WAVE...WITH RADAR ECHOES REFLECTING THIS
TREND. ALSO SINCE AROUND 1 AM MST...K3MW IN THE PARK RANGE HAS
REPORTED SNOW...AND EXPECT SHOWERS HAVE DEVELOPED AT OTHER
NORTHERN MOUNTAIN LOCATIONS AS WELL.
THE LOW CENTER WILL DROP FROM THE NORTHERN ROCKIES SOUTH-SOUTHEAST
ACROSS WY BY MID-MORNING...AND OVER NORTHWEST CO BY MIDDAY. ALSO A
NOT VERY DISTINCT SURFACE FRONT AHEAD OF THE UPPER LEVEL TROUGH
WILL SEEP OVER THE AREA FROM NORTHWEST TO SOUTHEAST EARLY TODAY.
AS A RESULT SNOW WILL CONTINUE TO SPREAD IN FROM THE NORTHWEST
THROUGH THE NEXT 3-12 HOURS. BY DAYLIGHT...SNOW SHOULD BE
WIDESPREAD ACROSS THE NORTHERN MOUNTAINS AND WILL FILL INTO THE
WEST-CENTRAL CO MOUNTAINS BY MID MORNING. SNOW WILL CONTINUE
THROUGH THE AFTERNOON AS THE -32/-33 COLD POOL AT 500 MB MOVES
OVER THE AREA. THE PRESENT FORECAST LOOKS ON TRACK WITH LOW-END
ADVISORY AMOUNTS IN THE NORTHERN AND WEST-CENTRAL MOUNTAINS...
FAVORING THE NORTHWEST FACING SLOPES. OTHER MOUNTAIN AREAS SHOULD
SEE A PERIOD OF SNOW...BUT WITH LIGHTER ACCUMULATIONS. VALLEYS
WILL SEE ISOLATED TO SCATTERED SNOW SHOWERS...WITH BETTER COVERAGE
OVER MUCH OF THE NORTH...AND LITTLE TO NO SHOWERS ALONG OUR WEST
AND SOUTHWEST BORDERS. BY LATE AFTERNOON ACTIVITY WILL BEGIN TO
DIMINISH IN THE WESTERN VALLEYS AS DRIER AIR MOVES IN. HOWEVER
SNOW WILL CONTINUE IN THE CO MOUNTAINS THROUGH THE EVENING THE AS
THE COLD AIR ALOFT REMAINS IN PLACE...AND THE FAVORED DENDRITIC
GROWTH LAYER WILL REMAIN SATURATED AND NEAR MOUNTAIN TOP LEVEL.
THEN BY LATE TONIGHT THE NORTH FLOW WILL CONTINUE TO PRODUCE LIGHT
SNOW ALONG THE NORTH SLOPES OF THOSE FAVORED NORTH AND CENTRAL
MOUNTAINS. THIS ACTIVITY WILL GRADUALLY DIMINISH TOWARDS SUNRISE
WED.
ONE AREA THAT SHOULD BE WATCHED IS THE UNCOMPAHGRE GORGE AT AND
NEAR OURAY CO. THIS AREA COULD PICK UP SOME DECENT ACCUMULATIONS
AS THE FLOW TURNS AROUND TO NORTH LATER TODAY THROUGH THIS
EVENING. HOWEVER...I CHOSE NOT TO INCLUDE CO ZONE 18 IN THE
ADVISORY AS THE DURATION WILL BE SHORT...AND THE HEAVIER
ACCUMULATIONS ARE EXPECTED TO BE LOCALIZED.
ANY REMAINING SHOWERS IN THE NORTHERN MOUNTAINS WILL QUICKLY WIND
DOWN THROUGH THE MORNING ON WED...WITH ONLY A FEW LINGERING BEYOND
MIDDAY NEAR THE CONTINENTAL DIVIDE.
BELOW NORMAL TEMPERATURES WILL CONTINUE.
.LONG TERM...(WEDNESDAY NIGHT THROUGH MONDAY)
ISSUED AT 355 AM MST TUE FEB 26 2013
RIDGE AMPLIFIES OVER THE WEST COAST STATES WEDNESDAY NIGHT INTO
THURSDAY NIGHT...BUT THE GFS AND TO A LESSER EXTENT THE SREF
INDICATE A DISTURBANCE WILL STREAM OVER THE NRN DIVIDE MOUNTAINS FOR
A CHANCE OF SNOW. THE ECMWF APPEARS TO BE TRENDING THIS DIRECTION
SO THE CHANCE POPS APPEAR WARRANTED. THIS WOULD BE A FAST MOVING
DISTURBANCE AND ANY SNOWFALL WILL BE LIGHT.
IN THE BIGGER PICTURE...A WARMING TREND WILL OCCUR THIS UPCOMING
WEEKEND AS A WARM RIDGE MOVES EAST ACROSS THE INTERMOUNTAIN WEST AND
ROCKY MOUNTAIN STATES ON SATURDAY AND SUNDAY. EXPECT WARMING TEMPS
AT ALL LOCATIONS...OR SLIGHTLY ABOVE AVERAGE COMPARED TO CLIMO.
RECENT TEMPS HAVE BEEN BELOW NORMAL...SO THIS WARMING WILL FEEL MORE
SIGNIFICANT THAN COMPARED TO CLIMO.
FORECAST CONFIDENCE DIMINISHES SUNDAY NIGHT AND MONDAY AS A
SIGNIFICANT SHORT WAVE PUNCHES ACROSS THE PACIFIC NORTHWEST AND NRN
INTERMOUNTAIN REGION. SOME ENTRAINMENT OF SUBTROPICAL MOISTURE IS
POSSIBLE AHEAD OF THIS FEATURE...AND THIS COULD LEAD TO CHANCE OF
PRECIPITATION SUNDAY NIGHT. MONDAY BECOMES MORE MURKY AS THE ECMWF
SHOWS MUCH COLDER AIR SPILLING INTO THE FORECAST AREA. WOULD LIKE
TO SEE SOME CONFIRMATION BY THE GFS OR RUN TO RUN CONTINUITY BY THE
EURO MODEL. WILL NOT MAKE TOO MANY CHANGES FROM THE CONSENSUS
OUTPUT...BUT DID LOWER MAX TEMPS ACROSS THE NWRN COLORADO VALLEYS.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z WEDNESDAY MORNING)
ISSUED AT 355 AM MST TUE FEB 26 2013
SNOW OVER THE NORTHERN AND CENTRAL MOUNTAINS EARLY THIS MORNING
WILL SPREAD INTO THE SOUTHERN MOUNTAINS BY AROUND 14Z...AND THEN
QUICKLY BECOME WIDESPREAD.
AN UPPER LEVEL TROUGH WILL PASS OVER THE AREA FROM 12Z/TUE TO
00Z/WED. AS A RESULT...AIRFIELDS WILL LIKELY SEE PERIODS OF MVFR
CIGS AND VSBY WITH BRIEF IFR CONDITIONS POSSIBLE IN HEAVIER
SHOWERS. PERSISTENT MOIST NORTHWESTERLY FLOW WILL FAVOR PROLONGED
PERIODS OF SNOW AT AIRPORTS EAST OF A 2OW KCAG-KMTJ LINE DURING
THE AFTERNOON. IN CONTRAST...NORTHWEST WINDS ARE UNFAVORABLE FOR
THE SOUTHERN AIRPORTS...SPECIFICALLY KCEZ...KDRO AND KPSO WHICH
WILL EXPERIENCE DRY DOWNSLOPE FLOW THROUGHOUT THE DAY. THE
MOUNTAINS WILL BE OBSCURED THROUGH 06Z WITH GUSTY NORTHWEST WINDS
AT TIMES RESULTING IN MECHANICAL TURBULENCE IN THE LEE OF PEAKS
AND RIDGES. MOUNTAIN SNOW WILL DIMINISH AFTER 06Z...BUT SNOW
SHOWERS WILL CONTINUE ALONG NORTHWEST-NORTH FACING SLOPES OF THE
NORTH AND WEST-CENTRAL COLORADO MOUNTAINS. THEREFORE MOUNTAIN
OBSCURATIONS WILL CONTINUE ALONG THESE SLOPES.
&&
.GJT WATCHES/WARNINGS/ADVISORIES...
CO...WINTER WEATHER ADVISORY UNTIL 9 AM MST WEDNESDAY FOR COZ004-009-
010-013.
UT...NONE.
&&
$$
UPDATE...PF
SHORT TERM...EH
LONG TERM...PF
AVIATION...EH
AREA FORECAST DISCUSSION
NWS JACKSON KY
652 AM EST TUE FEB 26 2013
.UPDATE...
ISSUED AT 652 AM EST TUE FEB 26 2013
DOWNSLOPING WINDS HAVE DEFINITELY TAKEN ITS TOLL ON THE RAIN AS IT
HAS PUSHED ACROSS THE AREA. MOST PLACES ARE GETTING LUCKY JUST TO
SQUEEZE OUT A HUNDREDTH OF AN INCH OF RAIN. THUS...HAVE DECIDED TO
TRIM POPS BACK...ESPECIALLY ACROSS THE SOUTH WHERE THINGS ARE ALREADY
STARTING TO DRY OUT. WITHIN THE NEXT FEW HOURS...ALL OF THE RAIN
SHOULD DEPART OFF TO THE NORTH...LEAVING BEHIND MAINLY DRY CONDITIONS
FOR THE BALANCE OF THE MORNING. HOWEVER...ANOTHER ROUND OF SHOWERS
STILL LOOKS ON TAP FOR THIS AFTERNOON...AS ANOTHER BAND OF SHOWERS
PUSHES EAST ACROSS THE AREA. THIS TIME THINGS MAY BE MORE CONVECTIVE
IN NATURE WITH THE THREAT OF STRONG WINDS AND SMALL HAIL STILL A
THREAT. LATEST HRRR DEFINITELY SUPPORTS SOME STRONG
SHOWERS/THUNDERSTORMS DEVELOPING BY EARLY AFTERNOON.
&&
.SHORT TERM...(TODAY THROUGH WEDNESDAY)
ISSUED AT 320 AM EST TUE FEB 26 2013
UPPER LEVEL LOW WILL CONTINUE TO PUSH INTO THE OHIO RIVER VALLEY
TODAY WITH AN OCCLUDING FRONTAL BOUNDARY CONTINUING TO LIFT NORTH
ACROSS THE AREA THIS MORNING. A BAND OF RAIN SHOWERS WILL PUSH NORTH
THROUGH THE EARLY MORNING HOURS. DOWNSLOPING SOUTHEAST WINDS WILL
CONTINUE TO TRY TO EAT AWAY AT THIS RAIN AS IT MOVES ACROSS THE AREA.
THIS WILL KEEP OVERALL RAINFALL AMOUNTS ON THE LIGHT SIDE...BUT WE
SHOULD SEE JUST ABOUT EVERYONE MEASURE BY 13Z. THIS BAND WILL QUICKLY
DEPART TO THE NORTH SHORTLY AFTER DAYBREAK...WITH ONLY SOME ISOLATED
TO SCATTERED SHOWERS LINGERING NEAR THE I-75 CORRIDOR. DOWNSLOPING
WINDS WILL LIKELY KEEP MOST OF THE ACTIVITY CLOSER TO CENTRAL
KENTUCKY. EVENTUALLY WINDS WILL VEER AROUND TO THE SOUTH OR SOUTHWEST
THIS AFTERNOON AS ANOTHER IMPULSE RIDES NORTHEAST ACROSS THE AREA.
THIS WILL TRIGGER ANOTHER ROUND OF SCATTERED TO NUMEROUS SHOWERS. IN
ADDITION...INSTABILITY REMAINS QUITE IMPRESSIVE...SO CANNOT RULE OUT
SOME ISOLATED THUNDERSTORMS WITH PERHAPS SOME SMALL HAIL. FINALLY A
THIRD WAVE WILL RIDE NORTHEAST ACROSS THE AREA THIS
EVENING...GENERATING SOME MORE SCATTERED SHOWERS. BY THIS
EVENING...INSTABILITY WILL DEPART TO THE NORTH...SO NO THUNDER
THROUGH THE EVENING HOURS. AS WINDS VEER TO THE SOUTHWEST
TONIGHT...LOWER CIGS MAY OVERSPREAD THE AREA...POSSIBLY LEADING TO
SOME PATCHY DRIZZLE LATE TONIGHT. HOWEVER...UNCERTAINTY EXISTS WITH
HOW MUCH LOW LEVEL MOISTURE WILL DEVELOP WHICH WOULD BE NEEDED TO
ACHIEVE ANY DRIZZLE. FINALLY...AS THE UPPER LEVEL LOW CONTINUES TO
ROTATE EASTWARD ACROSS THE OHIO RIVER VALLEY ON WEDNESDAY...THIS
SYSTEM WILL SEND A VIGOROUS SHORTWAVE SOUTHEAST ACROSS THE
AREA...GIVING WAY TO ANOTHER ROUND OF RAIN. COLDER AIR WILL ALSO
SETTLE SOUTHWARD AND AS WE WETBULB THROUGH THE EVENING...WE SHOULD
SEE SOME SNOW STARTING TO MIX IN AS WE HEAD INTO THE EVENING HOURS.
AS FOR THE WIND ADVISORY...GOING TO LEAVE THE COUNTIES NEAR THE
VIRGINIA BORDER IN THE ADVISORY. THE MESONET STATION AT DORTON IS HAS
GUSTED UP TO 38 MPH AND THIS SHOULD ONLY GO HIGHER AS THE SYSTEM
MOVES TOWARDS US TODAY.
.LONG TERM...(WEDNESDAY NIGHT THROUGH MONDAY)
ISSUED AT 350 AM EST TUE FEB 26 2013
THE MODELS ARE IN RELATIVELY GOOD AGREEMENT ALOFT THROUGH THE FIRST
PART OF THE EXTENDED...ESPECIALLY CONSIDERING THE AMPLIFIED NATURE OF
THE PATTERN. A DEEP AND LARGE CLOSED LOW WILL SLOWLY ROLL OUT OF THE
OHIO VALLEY ON THURSDAY WITH THE GFS RUNNING SLIGHTLY FASTER THAN THE
ECMWF. IN THE WAKE OF THIS...A STEADY STREAM OF UNCONSOLIDATED ENERGY
WILL SLIP THROUGH THE REGION INTO FRIDAY WHILE THE WESTERN EXTENT OF
IT STARTS TO CARVE OUT ANOTHER LOW OVER THE MID MISSISSIPPI VALLEY.
THIS LOW BECOMES BETTER ESTABLISHED ON SATURDAY OVER THE TENNESSEE
VALLEY...MOST IMPRESSIVE IN THE GFS AND WEAKER IN BOTH THE ECMWF AND
GEM. THE BASIC CONCEPT AND MAIN WEATHER DRIVERS ARE THE SAME FROM ALL
THE MODELS AS PLENTY OF ENERGY ROTATES THROUGH THE REGION DOWNSTREAM
OF A BURGEONING RIDGE THROUGH THE ROCKY MOUNTAIN STATES.
ACCORDINGLY...A BLENDED SOLUTION LOOKS REASONABLE THROUGH THE BULK
OF THE EXTENDED. THIS MID LEVEL LOW WILL GET SQUEEZED SOUTHEAST
THROUGH THE WEEKEND...BUT MANAGE TO MAINTAIN CYCLONIC FLOW OVER EAST
KENTUCKY UNTIL SUNDAY NIGHT WHEN IT WILL FINALLY MOVE OFF TO THE EAST
AS HEIGHTS RISE LOCALLY...IN RESPONSE TO A FLATTENING OF THE
FORMERLY ROBUST TROUGH TO THE WEST. A SMALL PORTION OF THIS RIDGE
THEN WILL SLIP THROUGH THE OHIO VALLEY ON MONDAY YIELDING THE HIGHEST
HEIGHTS OF THE LONG TERM PORTION OF THE FORECAST.
SENSIBLE WEATHER WILL FEATURE A CHILLY AND UNSETTLED TIME FRAME AT
LEAST INTO THE START OF THE WEEKEND. COLDER AIR WILL MOVE INTO THE
REGION ON NORTHWEST WINDS BEHIND THE DEEP SFC LOW SPINNING OFF TO
THE NORTHEAST EARLY IN THE PERIOD. THE LOW WILL MAINTAIN THE LOW
LEVEL MOISTURE OVER THE AREA WITH A COLD ENOUGH COLUMN OF AIR TO
SUPPORT SNOW FOR THE BULK OF THE TIME...THOUGH LIMITED DIURNAL RISES
WILL PROBABLY YIELD A MIX WITH RAIN EACH AFTERNOON. THE QPF WILL
ALSO BE RATHER LIMITED THROUGH THE FIRST PART OF THE WEEKEND ALSO
SERVING TO KEEP THE ACCUMULATIONS OF SNOW IN CHECK FOR MOST
LOCATIONS. WOULD ACTUALLY BE SURPRISED TO SEE MUCH IN THE WAY OF
ACCUMULATIONS DURING THE DAYTIME HOURS WITH A BETTER SHOT AT LIGHT
AMOUNTS STICKING EACH NIGHT. AMOUNTS WILL BE MAXIMIZED ON THE RIDGES
OF SOUTHEAST KENTUCKY WITH SOME OF THE PEAKS NEAR VIRGINIA LIKELY TO
HAVE MULTIPLE INCHES ON THE GROUND BY SUNDAY MORNING. THE REST OF THE
AREA WILL LIKELY SKATE BY WITH AN INCH OR LESS AND MAINLY JUST
SKIFFS OF VARYING THICKNESS. AS A RESULT...DO NOT FORESEE MUCH OF AN
IMPACT ON THE ROADS FOR THIS TIME PERIOD DESPITE THE CHILL AND
FREQUENT TIMES OF SNOW. THAT SAID...A FEW HEAVIER SNOW BURSTS OR
BANDS WILL BE POSSIBLY AND THAT COULD CAUSE BRIEF TRAVEL CHALLENGES
THROUGHOUT THE END OF THE WEEK AND INTO THE WEEKEND. DRIER AIR SHOULD
MOVE INTO THE REGION FROM THE NORTHWEST ON SUNDAY AND PUT AN END TO
MOST OF THE PCPN THREAT...BUT MAINTAIN THE BELOW NORMAL AIR MASS IN
PLACE. HIGH PRESSURE AND SOME SUNSHINE SHOULD RESULT IN DRY
CONDITIONS ALLOWING TEMPERATURES TO CREEP BACK UP CLOSER TO NORMAL
FOR MONDAY.
THE CR GRID LOAD CAME IN PRETTY GOOD GIVEN THE CONSENSUS PREFERENCE.
MADE ONLY MINOR CHANGES...MAINLY TO BEEF UP POPS IN THE SOUTHEAST
TERRAIN AND LIMIT THEM TO THE WEST. DID ALSO ADD SOME TERRAIN
DETAIL INTO THE LOWS BOTH SATURDAY AND SUNDAY NIGHTS.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z WEDNESDAY MORNING)
ISSUED AT 652 AM EST TUE FEB 26 2013
DOWNSLOPING WINDS WILL CONTINUE INTO THE AFTERNOON...KEEPING CEILINGS
SOLIDLY VFR THROUGH THE AFTERNOON AND PERHAPS EVEN THROUGH A GOOD
CHUNK OF THE EVENING. AS WINDS VEER AROUND TO THE SOUTHWEST LATE
TODAY...SOME LOWER CIGS MAY FINALLY WORK THEIR WAY ACROSS THE
AREA...BUT SHOULD REMAIN MVFR. STRONG GUSTY WINDS WILL CONTINUE TODAY
BEFORE SUBSIDING A BIT TONIGHT. AS CEILINGS LOWER TONIGHT...SOME
DRIZZLE MAY BE POSSIBLE.
&&
.JKL WATCHES/WARNINGS/ADVISORIES...
WIND ADVISORY UNTIL 4 PM EST THIS AFTERNOON FOR KYZ087-088-118-
120.
&&
$$
UPDATE...KAS
SHORT TERM...KAS
LONG TERM...GREIF
AVIATION...KAS
AREA FORECAST DISCUSSION
NWS WAKEFIELD VA
1023 AM EST TUE FEB 26 2013
.SYNOPSIS...
STRONG LOW PRESSURE WILL TRACK FROM THE LOWER TENNESSEE VALLEY TO
THE OHIO VALLEY TODAY. A SECONDARY LOW DEVELOPING OVER THE
SOUTHEAST IS EXPECTED TO PULL A WARM FRONT ACROSS THE REGION
LATER TODAY...RESULTING IN WIDESPREAD RAINFALL. DRY WEATHER
RETURNS ON WEDNESDAY, WITH GRADUALLY COOLER CONDITIONS FOR THE
LATTER HALF OF THE WEEK.
&&
.NEAR TERM /THROUGH TONIGHT/...
UPDATE AS OF 10 AM...
RAIN IS CURRENTLY SPREADING INTO SOUTHERN PORTIONS OF OUR FA AS
EXPECTED. THERE WAS A LITTLE SLEET AT THE ONSET AROUND
FARMVILLE...BUT THAT HAS SINCE ENDED AS TEMPS CONTINUE TO WARM SO
HAVE REMOVED MENTION FROM THE FORECAST. OTW...RAIN CONTINUES TO
SPREAD NORTH THROUGH THE DAY WITH NO OTHER CHANGES TO THE FORECAST
NEEDED AT THIS TIME.
PREVIOUS DISCUSSION... LATEST WATER VAPOR IMAGERY
SHOWS STRONG UPPER LOW LOCATED OVER THE LOWER MISSISSIPPI RVR
VALLEY EARLY THIS MORNING. AT THE SFC...POWERFUL AREA OF SFC LOW
PRESSURE CONTINUES TO LIFT NE ACROSS THE OZARKS/CENTRAL MS VLY,
WITH A WELL-DEFINED WARM CONVEYOR BELT EVIDENT ON IR/WV SAT
IMAGERY SPREADING PCPN ACROSS THE TN AND LOWER OH VLYS. FARTHER
SOUTH, A WARM FRONT WAS ANALYZED ALONG THE GULF COAST...EXTENDING
NEWD ALONG THE SE COAST. SECONDARY LOW PRESSURE WAS BEGINNING TO
DEVELOP ACROSS THE GULF COAST, WITH MSAS 3-HR PRESSURE FALLS ON
THE ORDER OF 3-4MB OVER S MS/GA. FINALLY, TO THE NORTH ~1024MB SFC
HIGH PRESSURE HAS RETREATED INTO THE NORTHEAST US, BUT CONTINUES
TO NOSE DOWN THE EAST COAST THIS MORNING.
INCREASING ISENTROPIC LIFT/SWLY FLOW WILL CONTINUE TO ADVECT
UPPER/MID LEVEL MOISTURE INTO THE REGION OVER THE NEXT FEW HOURS.
REGIONAL RADAR MOSAIC INDICATING PRECIP BREAKING OUT ACROSS
WESTERN CAROLINAS AT THIS HOUR, AND LIKELY NOT TO PUSH INTO FAR SW
CORNER OF AKQ CWA UNTIL AFTER SUNRISE. HAVE AGAIN LOWERED POP FOR
THE NEXT FEW HOURS, WITH HRRR DOING A GOOD JOB THUS FAR IN TIMING
PCPN SHIELD. HV LEANED IN ITS DIRECTION IN FURTHER SLOWING ONSET
OF POPS THIS MORNING, ESPECIALLY EASTERN SHORE COUNTIES.
AS EXPECTED, DRY ANTECEDENT AIRMASS OVER THE AREA HAS MODIFIED
LITTLE OVER THE PAST FEW HOURS, WITH DEWPOINTS STILL IN THE TEENS
TO LOW 20S ACROSS OUR E VA PIEDMONT COUNTIES. THUS, PRECIP STILL
SEVERAL HRS OFF. AS PRECIP BREAKS OUT ACROSS THE REGION AFTER
11-12Z, EXPECT THAT A BRIEF PERIOD OF SLEET WL MIX WITH RAIN, MOST
PREVALENT OVER OUR PIEDMONT COUNTIES. HOWEVER, AS SLUG OF
OVERRUNNING MOISTURE CONTINUES TO DRAW CLOSER AND DRIER AIR
CONTINUES TO ERODE, EXPECT DURATION OF ANY NON-LIQUID PCPN TO BE
QUITE BRIEF IN DURATION. NO ICE ACCRETION IS EXPECTED ON ROADWAYS.
THEREFORE, NO WINTER HEADLINES ARE NECESSARY ATTM.
FORECAST DETAILS HAVE CHANGED VERY LITTLE FROM PREVIOUS THINKING,
WITH A GENERAL MODEL CONSENSUS CONTINUES TO FAVOR TAKING THE SFC
LOW FROM CURRENT POSITION OVER E AR JUST SE OF KSTL INTO DOWNSTATE
IL BY TONIGHT. MEANWHILE, SECONDARY SFC LOW LOOKS TO SLIDE FROM
THE CENTRAL GULF COAST ACROSS THE COASTAL CAROLINAS. RAIN CHANCES
RATCHET UP QUICKLY THIS MORNING INTO THE AFTN AS WARM FRONT SLIPS
NORTH AND VERY MOIST AIRMASS PUSHES INTO THE AREA. SLUG OF STEADY
RAIN (MOD TO HVY AT TIMES) STILL LOOKS TO PUSH SW TO NE ACROSS THE
AREA FROM MID MORNING INTO THE EARLY EVENING, WITH RAIN ENDING
FROM S TO N AS WARM FRONT LIFTS NORTH OF THE AREA.
RAINFALL AMOUNTS WILL AVERAGE 0.65" TO 1.00" FOR THIS EVENT. NO
PROBLEMS EXPECTED WITH FLASH FLOOD GUIDANCE, SO NO HYDRO HEADLINES
ISSUED OR ANTICIPATED. REGARDING CONVECTIVE POTENTIAL OUTLOOKED
IN PREVIOUS DISCUSSIONS, SPC NOW HAS AREA OUTLOOKED IN A `GENERAL
THUNDER` AREA, WITH SLIGHT RISK SHUNTED FARTHER SOUTHEAST. THIS
JIVES WELL WITH CURRENT THINKING AS IT APPEARS THAT WARM SECTOR
REMAINS ORIENTED JUST SOUTHEAST OF THE AREA ACROSS FAR SE NC AND
POINTS SOUTH. NAM REMAINS MOST BULLISH WITH MLCAPE, WITH THE GFS
PREFERRING TO TAKE THE SECONDARY LOW ACROSS COASTAL CAROLINAS AS
THE NAM PUSHES LOW INLAND. NAM SOLN WOULD TAKE THE SFC LOW INTO
THE CORE OF THE STABLE CAD WEDGE. THE COOLER, MORE STABLE GFS
SOLUTION FOR THE LOCAL AREA APPEARS MOST LOGICAL...AND THE
FORECAST HAS BEEN TRENDED IN THIS DIRECTION.
FOR HIGHS, AS IS TYPICAL WITH STRONG CAD WEDGE SETUPS, GRADIENT
FROM PIEDMONT TO COASTAL NC COUNTIES WILL VARY BY 20-25 DEG F.
MAX TEMPS WILL RANGE FM THE LWR 40S NW...TO AROUND 60 IN NE NC.
&&
.SHORT TERM /WEDNESDAY THROUGH THURSDAY/...
WEDNESDAY AND THURSDAY GENERALLY CHARACTERIZED BY DEVELOPING UPPER
TROUGH OVER THE EASTERN CONUS, RESULTING IN GRADUALLY COOLER
CONDITIONS FOR THE MID TO LATE WEEK PERIOD.
SFC LOW AND ASSOCIATED FRONTAL BOUNDARY LIFT NE INTO NEW ENGLAND
EARLY ON WED AS UPPER LOW LINGERS OVER THE OHIO VALLEY/EASTERN
GREAT LAKES. DEEP WSW FLOW IN PLACE WILL BRING A MILD AFTERNOON
WITH HIGH TEMPERATURES IN THE UPR 50S TO MID 60S UNDER A PARTLY
SUNNY SKY. THE UPPER LOW MOVES EAST THROUGH PA ON THURSDAY WITH
THE MAJORITY OF THE MOISTURE/ENERGY WITH THIS SYSTEM STAYING TO
OUR NORTH. HOWEVER...HPC SOLN AS WELL AS THE ECMWF AND ITS
ENSEMBLES DO SUPPORT SHORTWAVE ENERGY PINWHEELING BEHIND THE
SYSTEM AND PIVOTING ACROSS THE REGION ON THURSDAY. PLUMES INDICATE
THIS WOULDN`T BE MUCH, BUT SOME SPOTTY SHRAS CAN`T BE RULED OUT
ACROSS NORTHERN/WESTERN SECTIONS ON THURSDAY. HAVE KEPT SLIGHT
CHC POPS (20%) IN PLACE AS A RESULT. OTHERWISE, EXPECT PARTLY
CLOUDY SKY EARLY GIVING WAY TO AFTN/EVENING CLEARING.
FOR TEMPERATURES, LOWS WED NIGHT IN THE 30S TO ~40. FORECAST HIGH
THU IN THE M/U 40S NORTH TO LOW 50S SOUTH.
&&
.LONG TERM /THURSDAY NIGHT THROUGH MONDAY/...
ANOMALOUS UPR LVL TROUGH TO REMAIN OVER THE ERN CONUS THROUGH THE
WEEKEND AND EARLY NEXT WEEK. THE TROUGH IS FCST TO SHIFT E/JUST
OFF THE COAST BY ERY NEXT WK. HV CONT W/ DRY FCST...W/ TEMPS TO
AVG ~10F (AOUND 1 STANDARD DEVIATION) BELOW NORMAL AND EACH DAY
HAVING VRB CLDNS/PCLDY NGTS. HI TEMPS RANGING THROUGH THE 40S.
MOST LO TEMPS FM THE M/U20S TO L30S.
&&
.AVIATION /16Z TUESDAY THROUGH SATURDAY/...
A WARM FRONT CURRENTLY DRAPED ALONG THE CAROLINA COAST WILL
GRADUALLY LIFT INTO THE MID ATLANTIC REGION THIS AFTERNOON AS A
COMPLEX LOW PRESSURE SYSTEM APPROACHES THE AREA FROM THE SOUTHWEST
TODAY. OVERRUNNING PRECIPITATION AND LOWER CIGS ASSOCIATED WITH
THE WARM FRONT WILL SPREAD INTO THE MID ATLANTIC REGION FROM THE
SOUTHWEST THIS MORNING AND BEGIN TO IMPACT KRIC...KPHF...KORF...AND
KECG AFTER 26/1600Z. DURING THIS AFTERNOON...RAINFALL WILL BECOME
MODERATE TO HEAVY AT TIMES (LOWERING CIGS TWD 500 FT AGL) AND E-SE
WINDS WILL BECOME BREEZY WITH GUSTS AROUND 25-30 KT. KSBY WILL
BEGIN TO EXPERIENCE SIMILAR CONDITIONS AFTER 26/2000Z.
PRECIPITATION WILL COME TO AN END FROM SOUTHWEST TO NORTHEAST
THROUGH TUESDAY EVENING AS LOW PRESSURE MOVES NORTHEAST AND OUT OF
THE AREA AFTER MIDNIGHT. BREEZY WINDS OVERNIGHT WILL HELP TO SCOUR
OUT LOWER CIGS AND IMPROVE VISIBILITIES ONCE PRECIP COMES TO AN END.
&&
.MARINE...
SCA HEADLINES HAVE BEEN ADJUSTED TO BEGIN EARLY THIS MORNING WITH
THE EXCEPTION OF CURRITUCK SOUND AND NRN COASTAL WATERS WHERE
WINDS WILL NOT INCREASE UNTIL THIS AFTN. HAVE ALREADY BEGUN TO SEE
A SLIGHT INCREASE IN WINDS OVER THE SRN BAY AS HIGH PRESSURE NOW
RESIDES OVER NEW ENGLAND AND THE PRESSURE GRADIENT TIGHTENS IN
RESPONSE TO THE APPROACHING LOW PRESSURE SYSTEM TO THE SOUTHWEST.
EAST WINDS ARE GENERALLY AOB 15 KT...HOWEVER THEY WILL TURN SE
AND INCREASE THIS AFTN...GUSTING BTWN 25-40 KT (DEPENDING ON
LOCATION). SE WINDS WILL PEAK EARLY THIS EVENING...THEN BECOME SW
AND DECREASE AFTER MIDNIGHT TONIGHT. SEAS ARE GENERALLY 4-5 FT
EARLY THIS MORNING AND WILL ALSO INCREASE TO 7-10 FT DURING THE
AFTN AND OVERNIGHT AS LOW PRESSURE MOVES UP THE MID ATLANTIC
SEABOARD AND INTENSIFIES.
AS THE LOW MOVES NORTH OF AREA WATERS...WARM MARINE AIR CONTINUED
TO BE PULLED INTO THE STORM AND WILL ACT TO INHIBIT ADDITIONAL
MIXING IN THE WAKE OF THE LOW. AFTER THAT...A PROLONGED PERIOD OF
OFFSHORE WINDS PREVAILS WED THROUGH AT LEAST FRIDAY. WINDS WILL
INITIALLY BE WSW ON WED...THEN WNW THU INTO THE WEEKEND. THE
POTENTIAL FOR EXTENDED SCA FLAGS EXISTS DURING THIS TIME DUE TO A
LONG PERIOD OF LOW LEVEL CAA...RESULTING IN WIND SPEEDS AOA 20-25 KT
AT TIMES.
&&
.TIDES/COASTAL FLOODING...
TIDAL ANOMALIES ARE STILL RUNNING ABOUT 0.5 TO 1.0 FT ABOVE
NORMAL...ESPECIALLY DURING THE HIGH TIDE CYCLE TO OCCUR THIS
EVENING. OVERALL WATER LEVELS ARE EXPECTED TO STAY ABOUT 1-2 FT
BELOW MINOR FLOODING THRESHOLDS...BUT WILL NEED TO MONITOR LATEST
FORECASTS CLOSELY DUE TO INCREASING E-SE WINDS THIS AFTN AND
EVENING.
&&
.AKQ WATCHES/WARNINGS/ADVISORIES...
MD...NONE.
NC...NONE.
VA...NONE.
MARINE...SMALL CRAFT ADVISORY UNTIL 1 AM EST WEDNESDAY FOR ANZ635>638.
SMALL CRAFT ADVISORY UNTIL 10 AM EST WEDNESDAY FOR ANZ630>632-
634.
SMALL CRAFT ADVISORY UNTIL 1 AM EST WEDNESDAY FOR ANZ633.
GALE WARNING UNTIL 1 AM EST WEDNESDAY FOR ANZ650-652-654.
SMALL CRAFT ADVISORY UNTIL 1 AM EST THURSDAY FOR ANZ656.
SMALL CRAFT ADVISORY UNTIL 7 AM EST THURSDAY FOR ANZ658.
&&
$$
SYNOPSIS...MAM
NEAR TERM...JDM/MAM
SHORT TERM...MAM
LONG TERM...ALB
AVIATION...BMD
MARINE...BMD
TIDES/COASTAL FLOODING...
AREA FORECAST DISCUSSION
NWS WAKEFIELD VA
513 AM EST TUE FEB 26 2013
.SYNOPSIS...
STRONG LOW PRESSURE WILL TRACK FROM THE LOWER TENNESSEE VALLEY TO
THE OHIO VALLEY TODAY. A SECONDARY LOW DEVELOPING OVER THE
SOUTHEAST IS EXPECTED TO PULL A WARM FRONT ACROSS THE REGION
LATER TODAY...RESULTING IN WIDESPREAD RAINFALL. DRY WEATHER
RETURNS ON WEDNESDAY, WITH GRADUALLY COOLER CONDITIONS FOR THE
LATTER HALF OF THE WEEK.
&&
.NEAR TERM /THROUGH TONIGHT/...
LATEST WATER VAPOR IMAGERY SHOWS STRONG UPPER LOW LOCATED OVER THE
LOWER MISSISSIPPI RVR VALLEY EARLY THIS MORNING. AT THE
SFC...POWERFUL AREA OF SFC LOW PRESSURE CONTINUES TO LIFT NE
ACROSS THE OZARKS/CENTRAL MS VLY, WITH A WELL-DEFINED WARM
CONVEYOR BELT EVIDENT ON IR/WV SAT IMAGERY SPREADING PCPN ACROSS
THE TN AND LOWER OH VLYS. FARTHER SOUTH, A WARM FRONT WAS ANALYZED
ALONG THE GULF COAST...EXTENDING NEWD ALONG THE SE COAST.
SECONDARY LOW PRESSURE WAS BEGINNING TO DEVELOP ACROSS THE GULF
COAST, WITH MSAS 3-HR PRESSURE FALLS ON THE ORDER OF 3-4MB OVER S
MS/GA. FINALLY, TO THE NORTH ~1024MB SFC HIGH PRESSURE HAS
RETREATED INTO THE NORTHEAST US, BUT CONTINUES TO NOSE DOWN THE
EAST COAST THIS MORNING.
INCREASING ISENTROPIC LIFT/SWLY FLOW WILL CONTINUE TO ADVECT
UPPER/MID LEVEL MOISTURE INTO THE REGION OVER THE NEXT FEW HOURS.
REGIONAL RADAR MOSAIC INDICATING PRECIP BREAKING OUT ACROSS
WESTERN CAROLINAS AT THIS HOUR, AND LIKELY NOT TO PUSH INTO FAR SW
CORNER OF AKQ CWA UNTIL AFTER SUNRISE. HAVE AGAIN LOWERED POP FOR
THE NEXT FEW HOURS, WITH HRRR DOING A GOOD JOB THUS FAR IN TIMING
PCPN SHIELD. HV LEANED IN ITS DIRECTION IN FURTHER SLOWING ONSET
OF POPS THIS MORNING, ESPECIALLY EASTERN SHORE COUNTIES.
AS EXPECTED, DRY ANTECEDENT AIRMASS OVER THE AREA HAS MODIFIED
LITTLE OVER THE PAST FEW HOURS, WITH DEWPOINTS STILL IN THE TEENS
TO LOW 20S ACROSS OUR E VA PIEDMONT COUNTIES. THUS, PRECIP STILL
SEVERAL HRS OFF. AS PRECIP BREAKS OUT ACROSS THE REGION AFTER
11-12Z, EXPECT THAT A BRIEF PERIOD OF SLEET WL MIX WITH RAIN, MOST
PREVALENT OVER OUR PIEDMONT COUNTIES. HOWEVER, AS SLUG OF
OVERRUNNING MOISTURE CONTINUES TO DRAW CLOSER AND DRIER AIR
CONTINUES TO ERODE, EXPECT DURATION OF ANY NON-LIQUID PCPN TO BE
QUITE BRIEF IN DURATION. NO ICE ACCRETION IS EXPECTED ON ROADWAYS.
THEREFORE, NO WINTER HEADLINES ARE NECESSARY ATTM.
FORECAST DETAILS HAVE CHANGED VERY LITTLE FROM PREVIOUS THINKING,
WITH A GENERAL MODEL CONSENSUS CONTINUES TO FAVOR TAKING THE SFC
LOW FROM CURRENT POSITION OVER E AR JUST SE OF KSTL INTO DOWNSTATE
IL BY TONIGHT. MEANWHILE, SECONDARY SFC LOW LOOKS TO SLIDE FROM
THE CENTRAL GULF COAST ACROSS THE COASTAL CAROLINAS. RAIN CHANCES
RATCHET UP QUICKLY THIS MORNING INTO THE AFTN AS WARM FRONT SLIPS
NORTH AND VERY MOIST AIRMASS PUSHES INTO THE AREA. SLUG OF STEADY
RAIN (MOD TO HVY AT TIMES) STILL LOOKS TO PUSH SW TO NE ACROSS THE
AREA FROM MID MORNING INTO THE EARLY EVENING, WITH RAIN ENDING
FROM S TO N AS WARM FRONT LIFTS NORTH OF THE AREA.
RAINFALL AMOUNTS WILL AVERAGE 0.65" TO 1.00" FOR THIS EVENT. NO
PROBLEMS EXPECTED WITH FLASH FLOOD GUIDANCE, SO NO HYDRO HEADLINES
ISSUED OR ANTICIPATED. REGARDING CONVECTIVE POTENTIAL OUTLOOKED
IN PREVIOUS DISCUSSIONS, SPC NOW HAS AREA OUTLOOKED IN A `GENERAL
THUNDER` AREA, WITH SLIGHT RISK SHUNTED FARTHER SOUTHEAST. THIS
JIVES WELL WITH CURRENT THINKING AS IT APPEARS THAT WARM SECTOR
REMAINS ORIENTED JUST SOUTHEAST OF THE AREA ACROSS FAR SE NC AND
POINTS SOUTH. NAM REMAINS MOST BULLISH WITH MLCAPE, WITH THE GFS
PREFERRING TO TAKE THE SECONDARY LOW ACROSS COASTAL CAROLINAS AS
THE NAM PUSHES LOW INLAND. NAM SOLN WOULD TAKE THE SFC LOW INTO
THE CORE OF THE STABLE CAD WEDGE. THE COOLER, MORE STABLE GFS
SOLUTION FOR THE LOCAL AREA APPEARS MOST LOGICAL...AND THE
FORECAST HAS BEEN TRENDED IN THIS DIRECTION.
FOR HIGHS, AS IS TYPICAL WITH STRONG CAD WEDGE SETUPS, GRADIENT
FROM PIEDMONT TO COASTAL NC COUNTIES WILL VARY BY 20-25 DEG F.
MAX TEMPS WILL RANGE FM THE LWR 40S NW...TO AROUND 60 IN NE NC.
&&
.SHORT TERM /WEDNESDAY THROUGH THURSDAY/...
WEDNESDAY AND THURSDAY GENERALLY CHARACTERIZED BY DEVELOPING UPPER
TROUGH OVER THE EASTERN CONUS, RESULTING IN GRADUALLY COOLER
CONDITIONS FOR THE MID TO LATE WEEK PERIOD.
SFC LOW AND ASSOCIATED FRONTAL BOUNDARY LIFT NE INTO NEW ENGLAND
EARLY ON WED AS UPPER LOW LINGERS OVER THE OHIO VALLEY/EASTERN
GREAT LAKES. DEEP WSW FLOW IN PLACE WILL BRING A MILD AFTERNOON
WITH HIGH TEMPERATURES IN THE UPR 50S TO MID 60S UNDER A PARTLY
SUNNY SKY. THE UPPER LOW MOVES EAST THROUGH PA ON THURSDAY WITH
THE MAJORITY OF THE MOISTURE/ENERGY WITH THIS SYSTEM STAYING TO
OUR NORTH. HOWEVER...HPC SOLN AS WELL AS THE ECMWF AND ITS
ENSEMBLES DO SUPPORT SHORTWAVE ENERGY PINWHEELING BEHIND THE
SYSTEM AND PIVOTING ACROSS THE REGION ON THURSDAY. PLUMES INDICATE
THIS WOULDN`T BE MUCH, BUT SOME SPOTTY SHRAS CAN`T BE RULED OUT
ACROSS NORTHERN/WESTERN SECTIONS ON THURSDAY. HAVE KEPT SLIGHT
CHC POPS (20%) IN PLACE AS A RESULT. OTHERWISE, EXPECT PARTLY
CLOUDY SKY EARLY GIVING WAY TO AFTN/EVENING CLEARING.
FOR TEMPERATURES, LOWS WED NIGHT IN THE 30S TO ~40. FORECAST HIGH
THU IN THE M/U 40S NORTH TO LOW 50S SOUTH.
&&
.LONG TERM /THURSDAY NIGHT THROUGH MONDAY/...
ANOMALOUS UPR LVL TROUGH TO REMAIN OVER THE ERN CONUS THROUGH THE
WEEKEND AND EARLY NEXT WEEK. THE TROUGH IS FCST TO SHIFT E/JUST
OFF THE COAST BY ERY NEXT WK. HV CONT W/ DRY FCST...W/ TEMPS TO
AVG ~10F (AOUND 1 STANDARD DEVIATION) BELOW NORMAL AND EACH DAY
HAVING VRB CLDNS/PCLDY NGTS. HI TEMPS RANGING THROUGH THE 40S.
MOST LO TEMPS FM THE M/U20S TO L30S.
&&
.AVIATION /10Z TUESDAY THROUGH SATURDAY/...
A WARM FRONT CURRENTLY DRAPED ALONG THE CAROLINA COAST WILL
GRADUALLY LIFT INTO THE MID ATLANTIC REGION THIS AFTERNOON AS A
COMPLEX LOW PRESSURE SYSTEM APPROACHES THE AREA FROM THE SOUTHWEST
TODAY. OVERRUNNING PRECIPITATION AND LOWER CIGS ASSOCIATED WITH
THE WARM FRONT WILL SPREAD INTO THE MID ATLANTIC REGION FROM THE
SOUTHWEST THIS MORNING AND BEGIN TO IMPACT KRIC...KPHF...KORF...AND
KECG AFTER 26/1600Z. DURING THIS AFTERNOON...RAINFALL WILL BECOME
MODERATE TO HEAVY AT TIMES (LOWERING CIGS TWD 500 FT AGL) AND E-SE
WINDS WILL BECOME BREEZY WITH GUSTS AROUND 25-30 KT. KSBY WILL
BEGIN TO EXPERIENCE SIMILAR CONDITIONS AFTER 26/2000Z.
PRECIPITATION WILL COME TO AN END FROM SOUTHWEST TO NORTHEAST
THROUGH TUESDAY EVENING AS LOW PRESSURE MOVES NORTHEAST AND OUT OF
THE AREA AFTER MIDNIGHT. BREEZY WINDS OVERNIGHT WILL HELP TO SCOUR
OUT LOWER CIGS AND IMPROVE VISIBILITIES ONCE PRECIP COMES TO AN END.
&&
.MARINE...
SCA HEADLINES HAVE BEEN ADJUSTED TO BEGIN EARLY THIS MORNING WITH
THE EXCEPTION OF CURRITUCK SOUND AND NRN COASTAL WATERS WHERE
WINDS WILL NOT INCREASE UNTIL THIS AFTN. HAVE ALREADY BEGUN TO SEE
A SLIGHT INCREASE IN WINDS OVER THE SRN BAY AS HIGH PRESSURE NOW
RESIDES OVER NEW ENGLAND AND THE PRESSURE GRADIENT TIGHTENS IN
RESPONSE TO THE APPROACHING LOW PRESSURE SYSTEM TO THE SOUTHWEST.
EAST WINDS ARE GENERALLY AOB 15 KT...HOWEVER THEY WILL TURN SE
AND INCREASE THIS AFTN...GUSTING BTWN 25-40 KT (DEPENDING ON
LOCATION). SE WINDS WILL PEAK EARLY THIS EVENING...THEN BECOME SW
AND DECREASE AFTER MIDNIGHT TONIGHT. SEAS ARE GENERALLY 4-5 FT
EARLY THIS MORNING AND WILL ALSO INCREASE TO 7-10 FT DURING THE
AFTN AND OVERNIGHT AS LOW PRESSURE MOVES UP THE MID ATLANTIC
SEABOARD AND INTENSIFIES.
AS THE LOW MOVES NORTH OF AREA WATERS...WARM MARINE AIR CONTINUED
TO BE PULLED INTO THE STORM AND WILL ACT TO INHIBIT ADDITIONAL
MIXING IN THE WAKE OF THE LOW. AFTER THAT...A PROLONGED PERIOD OF
OFFSHORE WINDS PREVAILS WED THROUGH AT LEAST FRIDAY. WINDS WILL
INITIALLY BE WSW ON WED...THEN WNW THU INTO THE WEEKEND. THE
POTENTIAL FOR EXTENDED SCA FLAGS EXISTS DURING THIS TIME DUE TO A
LONG PERIOD OF LOW LEVEL CAA...RESULTING IN WIND SPEEDS AOA 20-25 KT
AT TIMES.
&&
.TIDES/COASTAL FLOODING...
TIDAL ANOMALIES ARE STILL RUNNING ABOUT 0.5 TO 1.0 FT ABOVE
NORMAL...ESPECIALLY DURING THE HIGH TIDE CYCLE TO OCCUR THIS
EVENING. OVERALL WATER LEVELS ARE EXPECTED TO STAY ABOUT 1-2 FT
BELOW MINOR FLOODING THRESHOLDS...BUT WILL NEED TO MONITOR LATEST
FORECASTS CLOSELY DUE TO INCREASING E-SE WINDS THIS AFTN AND
EVENING.
&&
.AKQ WATCHES/WARNINGS/ADVISORIES...
MD...NONE.
NC...NONE.
VA...NONE.
MARINE...SMALL CRAFT ADVISORY UNTIL 1 AM EST WEDNESDAY FOR ANZ635>638.
SMALL CRAFT ADVISORY UNTIL 10 AM EST WEDNESDAY FOR ANZ630>632-
634.
SMALL CRAFT ADVISORY FROM NOON TODAY TO 1 AM EST WEDNESDAY FOR
ANZ633.
SMALL CRAFT ADVISORY UNTIL 4 PM EST THIS AFTERNOON FOR ANZ650-
652-654.
GALE WARNING FROM 4 PM THIS AFTERNOON TO 1 AM EST WEDNESDAY
FOR ANZ650-652-654.
SMALL CRAFT ADVISORY UNTIL 1 AM EST THURSDAY FOR ANZ656.
SMALL CRAFT ADVISORY UNTIL 7 AM EST THURSDAY FOR ANZ658.
&&
$$
SYNOPSIS...MAM
NEAR TERM...JDM/MAM
SHORT TERM...MAM
LONG TERM...ALB
AVIATION...BMD
MARINE...BMD
TIDES/COASTAL FLOODING...
AREA FORECAST DISCUSSION
NWS WAKEFIELD VA
505 AM EST TUE FEB 26 2013
.SYNOPSIS...
STRONG LOW PRESSURE WILL TRACK FROM THE LOWER TENNESSEE VALLEY TO
THE GREAT LAKES TODAY. A SECONDARY LOW DEVELOPING OVER THE
SOUTHERN APPALACHIANS IS EXPECTED TO PULLING A WARM FRONT UP INTO
THE REGION LATER TODAY...RESULTING IN WIDESPREAD RAINFALL. DRY
WEATHER RETURNS ON WEDNESDAY, WITH GRADUALLY COOLER CONDITIONS
FOR THE LATTER HALF OF THE WEEK.
&&
.NEAR TERM /THROUGH TONIGHT/...
LATEST WATER VAPOR IMAGERY SHOWS STRONG UPPER LOW LOCATED OVER THE
LOWER MISSISSIPPI RVR VALLEY EARLY THIS MORNING. AT THE
SFC...POWERFUL AREA OF SFC LOW PRESSURE CONTINUES TO LIFT NE
ACROSS THE OZARKS/CENTRAL MS VLY, WITH A WELL-DEFINED WARM
CONVEYOR BELT EVIDENT ON IR/WV SAT IMAGERY SPREADING PCPN ACROSS
THE TN AND LOWER OH VLYS. FARTHER SOUTH, A WARM FRONT WAS ANALYZED
ALONG THE GULF COAST...EXTENDING NEWD ALONG THE SE COAST.
SECONDARY LOW PRESSURE WAS BEGINNING TO DEVELOP ACROSS THE GULF
COAST, WITH MSAS 3-HR PRESSURE FALLS ON THE ORDER OF 3-4MB OVER S
MS/GA. FINALLY, TO THE NORTH ~1024MB SFC HIGH PRESSURE HAS
RETREATED INTO THE NORTHEAST US, BUT CONTINUES TO NOSE DOWN THE
EAST COAST THIS MORNING.
INCREASING ISENTROPIC LIFT/SWLY FLOW WILL CONTINUE TO ADVECT
UPPER/MID LEVEL MOISTURE INTO THE REGION OVER THE NEXT FEW HOURS.
REGIONAL RADAR MOSAIC INDICATING PRECIP BREAKING OUT ACROSS
WESTERN CAROLINAS AT THIS HOUR, AND LIKELY NOT TO PUSH INTO FAR SW
CORNER OF AKQ CWA UNTIL AFTER SUNRISE. HAVE AGAIN LOWERED POP FOR
THE NEXT FEW HOURS, WITH HRRR DOING A GOOD JOB THUS FAR IN TIMING
PCPN SHIELD. HV LEANED IN ITS DIRECTION IN FURTHER SLOWING ONSET
OF POPS THIS MORNING, ESPECIALLY EASTERN SHORE COUNTIES.
AS EXPECTED, DRY ANTECEDENT AIRMASS OVER THE AREA HAS MODIFIED
LITTLE OVER THE PAST FEW HOURS, WITH DEWPOINTS STILL IN THE TEENS
TO LOW 20S ACROSS OUR E VA PIEDMONT COUNTIES. THUS, PRECIP STILL
SEVERAL HRS OFF. AS PRECIP BREAKS OUT ACROSS THE REGION AFTER
11-12Z, EXPECT THAT A BRIEF PERIOD OF SLEET WL MIX WITH RAIN, MOST
PREVALENT OVER OUR PIEDMONT COUNTIES. HOWEVER, AS SLUG OF
OVERRUNNING MOISTURE CONTINUES TO DRAW CLOSER AND DRIER AIR
CONTINUES TO ERODE, EXPECT DURATION OF ANY NON-LIQUID PCPN TO BE
QUITE BRIEF IN DURATION. NO ICE ACCRETION IS EXPECTED ON ROADWAYS.
THEREFORE, NO WINTER HEADLINES ARE NECESSARY ATTM.
FORECAST DETAILS HAVE CHANGED VERY LITTLE FROM PREVIOUS THINKING,
WITH A GENERAL MODEL CONSENSUS CONTINUES TO FAVOR TAKING THE SFC
LOW FROM CURRENT POSITION OVER E AR JUST SE OF KSTL INTO DOWNSTATE
IL BY TONIGHT. MEANWHILE, SECONDARY SFC LOW LOOKS TO SLIDE FROM
THE CENTRAL GULF COAST ACROSS THE COASTAL CAROLINAS. RAIN CHANCES
RATCHET UP QUICKLY THIS MORNING INTO THE AFTN AS WARM FRONT SLIPS
NORTH AND VERY MOIST AIRMASS PUSHES INTO THE AREA. SLUG OF STEADY
RAIN (MOD TO HVY AT TIMES) STILL LOOKS TO PUSH SW TO NE ACROSS THE
AREA FROM MID MORNING INTO THE EARLY EVENING, WITH RAIN ENDING
FROM S TO N AS WARM FRONT LIFTS NORTH OF THE AREA.
RAINFALL AMOUNTS WILL AVERAGE 0.65" TO 1.00" FOR THIS EVENT. NO
PROBLEMS EXPECTED WITH FLASH FLOOD GUIDANCE, SO NO HYDRO HEADLINES
ISSUED OR ANTICIPATED. REGARDING CONVECTIVE POTENTIAL OUTLOOKED
IN PREVIOUS DISCUSSIONS, SPC NOW HAS AREA OUTLOOKED IN A `GENERAL
THUNDER` AREA, WITH SLIGHT RISK SHUNTED FARTHER SOUTHEAST. THIS
JIVES WELL WITH CURRENT THINKING AS IT APPEARS THAT WARM SECTOR
REMAINS ORIENTED JUST SOUTHEAST OF THE AREA ACROSS FAR SE NC AND
POINTS SOUTH. NAM REMAINS MOST BULLISH WITH MLCAPE, WITH THE GFS
PREFERRING TO TAKE THE SECONDARY LOW ACROSS COASTAL CAROLINAS AS
THE NAM PUSHES LOW INLAND. NAM SOLN WOULD TAKE THE SFC LOW INTO
THE CORE OF THE STABLE CAD WEDGE. THE COOLER, MORE STABLE GFS
SOLUTION FOR THE LOCAL AREA APPEARS MOST LOGICAL...AND THE
FORECAST HAS BEEN TRENDED IN THIS DIRECTION.
FOR HIGHS, AS IS TYPICAL WITH STRONG CAD WEDGE SETUPS, GRADIENT
FROM PIEDMONT TO COASTAL NC COUNTIES WILL VARY BY 20-25 DEG F.
MAX TEMPS WILL RANGE FM THE LWR 40S NW...TO AROUND 60 IN NE NC.
&&
.SHORT TERM /WEDNESDAY THROUGH THURSDAY/...
WEDNESDAY AND THURSDAY GENERALLY CHARACTERIZED BY DEVELOPING UPPER
TROUGH OVER THE EASTERN CONUS, RESULTING IN GRADUALLY COOLER
CONDITIONS FOR THE MID TO LATE WEEK PERIOD.
SFC LOW AND ASSOCIATED FRONTAL BOUNDARY LIFT NE INTO NEW ENGLAND
EARLY ON WED AS UPPER LOW LINGERS OVER THE OHIO VALLEY/EASTERN
GREAT LAKES. DEEP WSW FLOW IN PLACE WILL BRING A MILD AFTERNOON
WITH HIGH TEMPERATURES IN THE UPR 50S TO MID 60S UNDER A PARTLY
SUNNY SKY. THE UPPER LOW MOVES EAST THROUGH PA ON THURSDAY WITH
THE MAJORITY OF THE MOISTURE/ENERGY WITH THIS SYSTEM STAYING TO
OUR NORTH. HOWEVER...HPC SOLN AS WELL AS THE ECMWF AND ITS
ENSEMBLES DO SUPPORT SHORTWAVE ENERGY PINWHEELING BEHIND THE
SYSTEM AND PIVOTING ACROSS THE REGION ON THURSDAY. PLUMES INDICATE
THIS WOULDN`T BE MUCH, BUT SOME SPOTTY SHRAS CAN`T BE RULED OUT
ACROSS NORTHERN/WESTERN SECTIONS ON THURSDAY. HAVE KEPT SLIGHT
CHC POPS (20%) IN PLACE AS A RESULT. OTHERWISE, EXPECT PARTLY
CLOUDY SKY EARLY GIVING WAY TO AFTN/EVENING CLEARING.
FOR TEMPERATURES, LOWS WED NIGHT IN THE 30S TO ~40. FORECAST HIGH
THU IN THE M/U 40S NORTH TO LOW 50S SOUTH.
&&
.LONG TERM /THURSDAY NIGHT THROUGH MONDAY/...
ANOMALOUS UPR LVL TROUGH TO REMAIN OVER THE ERN CONUS THROUGH THE
WEEKEND AND EARLY NEXT WEEK. THE TROUGH IS FCST TO SHIFT E/JUST
OFF THE COAST BY ERY NEXT WK. HV CONT W/ DRY FCST...W/ TEMPS TO
AVG ~10F (AOUND 1 STANDARD DEVIATION) BELOW NORMAL AND EACH DAY
HAVING VRB CLDNS/PCLDY NGTS. HI TEMPS RANGING THROUGH THE 40S.
MOST LO TEMPS FM THE M/U20S TO L30S.
&&
.AVIATION /10Z TUESDAY THROUGH SATURDAY/...
A WARM FRONT CURRENTLY DRAPED ALONG THE CAROLINA COAST WILL
GRADUALLY LIFT INTO THE MID ATLANTIC REGION THIS AFTERNOON AS A
COMPLEX LOW PRESSURE SYSTEM APPROACHES THE AREA FROM THE SOUTHWEST
TODAY. OVERRUNNING PRECIPITATION AND LOWER CIGS ASSOCIATED WITH
THE WARM FRONT WILL SPREAD INTO THE MID ATLANTIC REGION FROM THE
SOUTHWEST THIS MORNING AND BEGIN TO IMPACT KRIC...KPHF...KORF...AND
KECG AFTER 26/1600Z. DURING THIS AFTERNOON...RAINFALL WILL BECOME
MODERATE TO HEAVY AT TIMES (LOWERING CIGS TWD 500 FT AGL) AND E-SE
WINDS WILL BECOME BREEZY WITH GUSTS AROUND 25-30 KT. KSBY WILL
BEGIN TO EXPERIENCE SIMILAR CONDITIONS AFTER 26/2000Z.
PRECIPITATION WILL COME TO AN END FROM SOUTHWEST TO NORTHEAST
THROUGH TUESDAY EVENING AS LOW PRESSURE MOVES NORTHEAST AND OUT OF
THE AREA AFTER MIDNIGHT. BREEZY WINDS OVERNIGHT WILL HELP TO SCOUR
OUT LOWER CIGS AND IMPROVE VISIBILITIES ONCE PRECIP COMES TO AN END.
&&
.MARINE...
SCA HEADLINES HAVE BEEN ADJUSTED TO BEGIN EARLY THIS MORNING WITH
THE EXCEPTION OF CURRITUCK SOUND AND NRN COASTAL WATERS WHERE
WINDS WILL NOT INCREASE UNTIL THIS AFTN. HAVE ALREADY BEGUN TO SEE
A SLIGHT INCREASE IN WINDS OVER THE SRN BAY AS HIGH PRESSURE NOW
RESIDES OVER NEW ENGLAND AND THE PRESSURE GRADIENT TIGHTENS IN
RESPONSE TO THE APPROACHING LOW PRESSURE SYSTEM TO THE SOUTHWEST.
EAST WINDS ARE GENERALLY AOB 15 KT...HOWEVER THEY WILL TURN SE
AND INCREASE THIS AFTN...GUSTING BTWN 25-40 KT (DEPENDING ON
LOCATION). SE WINDS WILL PEAK EARLY THIS EVENING...THEN BECOME SW
AND DECREASE AFTER MIDNIGHT TONIGHT. SEAS ARE GENERALLY 4-5 FT
EARLY THIS MORNING AND WILL ALSO INCREASE TO 7-10 FT DURING THE
AFTN AND OVERNIGHT AS LOW PRESSURE MOVES UP THE MID ATLANTIC
SEABOARD AND INTENSIFIES.
AS THE LOW MOVES NORTH OF AREA WATERS...WARM MARINE AIR CONTINUED
TO BE PULLED INTO THE STORM AND WILL ACT TO INHIBIT ADDITIONAL
MIXING IN THE WAKE OF THE LOW. AFTER THAT...A PROLONGED PERIOD OF
OFFSHORE WINDS PREVAILS WED THROUGH AT LEAST FRIDAY. WINDS WILL
INITIALLY BE WSW ON WED...THEN WNW THU INTO THE WEEKEND. THE
POTENTIAL FOR EXTENDED SCA FLAGS EXISTS DURING THIS TIME DUE TO A
LONG PERIOD OF LOW LEVEL CAA...RESULTING IN WIND SPEEDS AOA 20-25 KT
AT TIMES.
&&
.TIDES/COASTAL FLOODING...
TIDAL ANOMALIES ARE STILL RUNNING ABOUT 0.5 TO 1.0 FT ABOVE
NORMAL...ESPECIALLY DURING THE HIGH TIDE CYCLE TO OCCUR THIS
EVENING. OVERALL WATER LEVELS ARE EXPECTED TO STAY ABOUT 1-2 FT
BELOW MINOR FLOODING THRESHOLDS...BUT WILL NEED TO MONITOR LATEST
FORECASTS CLOSELY DUE TO INCREASING E-SE WINDS THIS AFTN AND
EVENING.
&&
.AKQ WATCHES/WARNINGS/ADVISORIES...
MD...NONE.
NC...NONE.
VA...NONE.
MARINE...SMALL CRAFT ADVISORY UNTIL 1 AM EST WEDNESDAY FOR ANZ635>638.
SMALL CRAFT ADVISORY UNTIL 10 AM EST WEDNESDAY FOR ANZ630>632-
634.
SMALL CRAFT ADVISORY FROM NOON TODAY TO 1 AM EST WEDNESDAY FOR
ANZ633.
SMALL CRAFT ADVISORY UNTIL 4 PM EST THIS AFTERNOON FOR ANZ650-
652-654.
GALE WARNING FROM 4 PM THIS AFTERNOON TO 1 AM EST WEDNESDAY
FOR ANZ650-652-654.
SMALL CRAFT ADVISORY UNTIL 1 AM EST THURSDAY FOR ANZ656.
SMALL CRAFT ADVISORY UNTIL 7 AM EST THURSDAY FOR ANZ658.
&&
$$
SYNOPSIS...MAM
NEAR TERM...JDM/MAM
SHORT TERM...MAM
LONG TERM...ALB
AVIATION...BMD
MARINE...BMD
TIDES/COASTAL FLOODING...
AREA FORECAST DISCUSSION
NWS WAKEFIELD VA
500 AM EST TUE FEB 26 2013
.SYNOPSIS...
STRONG LOW PRESSURE WILL TRACK FROM THE LOWER TENNESSEE VALLEY TO
THE GREAT LAKES TODAY. A SECONDARY LOW DEVELOPING OVER THE
SOUTHERN APPALACHIANS IS EXPECTED TO PULLING A WARM FRONT UP INTO
THE REGION LATER TODAY...RESULTING IN WIDESPREAD RAINFALL. DRY
WEATHER RETURNS ON WEDNESDAY, WITH GRADUALLY COOLER CONDITIONS
FOR THE LATTER HALF OF THE WEEK.
&&
.NEAR TERM /THROUGH TONIGHT/...
LATEST WATER VAPOR IMAGERY SHOWS STRONG UPPER LOW LOCATED OVER THE
LOWER MISSISSIPPI RVR VALLEY EARLY THIS MORNING. AT THE
SFC...POWERFUL AREA OF SFC LOW PRESSURE CONTINUES TO LIFT NE
ACROSS THE OZARKS/CENTRAL MS VLY, WITH A WELL-DEFINED WARM
CONVEYOR BELT EVIDENT ON IR/WV SAT IMAGERY SPREADING PCPN ACROSS
THE TN AND LOWER OH VLYS. FARTHER SOUTH, A WARM FRONT WAS ANALYZED
ALONG THE GULF COAST...EXTENDING NEWD ALONG THE SE COAST.
SECONDARY LOW PRESSURE WAS BEGINNING TO DEVELOP ACROSS THE GULF
COAST, WITH MSAS 3-HR PRESSURE FALLS ON THE ORDER OF 3-4MB OVER S
MS/GA. FINALLY, TO THE NORTH ~1024MB SFC HIGH PRESSURE HAS
RETREATED INTO THE NORTHEAST US, BUT CONTINUES TO NOSE DOWN THE
EAST COAST THIS MORNING.
INCREASING ISENTROPIC LIFT/SWLY FLOW WILL CONTINUE TO ADVECT
UPPER/MID LEVEL MOISTURE INTO THE REGION OVER THE NEXT FEW HOURS.
REGIONAL RADAR MOSAIC INDICATING PRECIP BREAKING OUT ACROSS
WESTERN CAROLINAS AT THIS HOUR, AND LIKELY NOT TO PUSH INTO FAR SW
CORNER OF AKQ CWA UNTIL AFTER SUNRISE. HAVE AGAIN LOWERED POP FOR
THE NEXT FEW HOURS, WITH HRRR DOING A GOOD JOB THUS FAR IN TIMING
PCPN SHIELD.
AS EXPECTED, DRY ANTECEDENT AIRMASS OVER THE AREA HAS MODIFIED
LITTLE OVER THE PAST FEW HOURS, WITH DEWPOINTS STILL IN THE TEENS
TO LOW 20S ACROSS OUR E VA PIEDMONT COUNTIES. THUS, PRECIP STILL
LKLY SEVERAL HRS OFF. AS PRECIP BREAKS OUT ACROSS THE REGION AFTER
SUNRISE EXPECT A BRIEF PERIOD OF SLEET TO MIX WITH RAIN ACROSS
OUR PIEDMONT COUNTIES. HOWEVER, AS SLUG OF OVERRUNNING MOISTURE
CONTINUES TO DRAW CLOSER AND DRIER AIR CONTINUES TO ERODE, EXPECT
DURATION OF ANY NON-LIQUID PCPN TO BE QUITE BRIEF.
FROM THERE, FORECAST DETAILS HAVE CHANGED VERY LITTLE FROM
PREVIOUS THINKING, WITH A GENERAL MODEL CONSENSUS CONTINUES TO
FAVOR TAKING THE SFC LOW FROM CURRENT POSITION OVER E AR JUST SE
OF KSTL INTO DOWNSTATE IL BY TONIGHT. MEANWHILE, SECONDARY SFC
LOW LOOKS TO SLIDE FROM THE CENTRAL GULF COAST ACROSS THE COASTAL
CAROLINAS. RAIN CHANCES RATCHET UP QUICKLY THIS MORNING INTO THE
AFTN AS WARM FRONT SLIPS NORTH AND VERY MOIST AIRMASS PUSHES INTO
THE AREA. STEADY RAIN LOOKS TO PUSH SW TO NE ACROSS THE AREA FROM
MID MORNING INTO THE EARLY EVENING, WITH RAIN ENDING FROM S TO N
AS WARM FRONT LIFTS NORTH OF THE AREA.
RAINFALL AMOUNTS WILL AVERAGE 0.75" TO 1.50" FOR THIS EVENT. NO
PROBLEMS EXPECTED WITH FLASH FLOOD GUIDANCE, SO NO HEADLINES
ANTICIPATED. SPC HAS AREA OUTLOOKED IN A `GENERAL THUNDER` AREA,
WITH SLIGHT RISK SHUNTED FARTHER SOUTHEAST. THIS JIVES WELL WITH
CURRENT THINKING AS IT APPEARS THAT WARM SECTOR REMAINS ORIENTED
JUST SOUTHEAST OF THE AREA ACROSS FAR SE NC AND POINTS SOUTH. NAM
REMAINS MOST BULLISH WITH MLCAPE. HOWEVER, EVEN THAT SOLUTION
RESULTING IN A MODESTLY UNSTABLE AIRMASS ALOFT, WITH THE BL LKLY
REMAINING STABLE THROUGHOUT.
&&
.SHORT TERM /WEDNESDAY THROUGH THURSDAY/...
WEDNESDAY AND THURSDAY GENERALLY CHARACTERIZED BY DEVELOPING UPPER
TROUGH OVER THE EASTERN CONUS, RESULTING IN GRADUALLY COOLER
CONDITIONS FOR THE MID TO LATE WEEK PERIOD.
SFC LOW AND ASSOCIATED FRONTAL BOUNDARY LIFT NE INTO NEW ENGLAND
EARLY ON WED AS UPPER LOW LINGERS OVER THE OHIO VALLEY/EASTERN
GREAT LAKES. DEEP WSW FLOW IN PLACE WILL BRING A MILD AFTERNOON
WITH HIGH TEMPERATURES IN THE UPR 50S TO MID 60S UNDER A PARTLY
SUNNY SKY. THE UPPER LOW MOVES EAST THROUGH PA ON THURSDAY WITH
THE MAJORITY OF THE MOISTURE/ENERGY WITH THIS SYSTEM STAYING TO
OUR NORTH. HOWEVER...HPC SOLN AS WELL AS THE ECMWF AND ITS
ENSEMBLES DO SUPPORT SHORTWAVE ENERGY PINWHEELING BEHIND THE
SYSTEM AND PIVOTING ACROSS THE REGION ON THURSDAY. PLUMES INDICATE
THIS WOULDN`T BE MUCH, BUT SOME SPOTTY SHRAS CAN`T BE RULED OUT
ACROSS NORTHERN/WESTERN SECTIONS ON THURSDAY. HAVE KEPT SLIGHT
CHC POPS (20%) IN PLACE AS A RESULT. OTHERWISE, EXPECT PARTLY
CLOUDY SKY EARLY GIVING WAY TO AFTN/EVENING CLEARING.
FOR TEMPERATURES, LOWS WED NIGHT IN THE 30S TO ~40. FORECAST HIGH
THU IN THE M/U 40S NORTH TO LOW 50S SOUTH.
&&
.LONG TERM /THURSDAY NIGHT THROUGH MONDAY/...
ANOMALOUS UPR LVL TROUGH TO RMN OVR THE ERN CONUS THROUGH MUCH OF
THE EXTENDED PD. THE TROUGH FCST TO SHIFT E/JUST OFF THE CST BY ERY
NEXT WK. WILL CONT W/ DRY FCST...W/ TEMPS AVGG 5-10F BLO NRML AND
EACH DAY HAVING VRB CLDNS/PCLDY NGTS. HI TEMPS RANGING THROUGH THE
40S. MOST LO TEMPS FM THE M/U20S TO L30S.
&&
.AVIATION /10Z TUESDAY THROUGH SATURDAY/...
A WARM FRONT CURRENTLY DRAPED ALONG THE CAROLINA COAST WILL
GRADUALLY LIFT INTO THE MID ATLANTIC REGION THIS AFTERNOON AS A
COMPLEX LOW PRESSURE SYSTEM APPROACHES THE AREA FROM THE SOUTHWEST
TODAY. OVERRUNNING PRECIPITATION AND LOWER CIGS ASSOCIATED WITH
THE WARM FRONT WILL SPREAD INTO THE MID ATLANTIC REGION FROM THE
SOUTHWEST THIS MORNING AND BEGIN TO IMPACT KRIC...KPHF...KORF...AND
KECG AFTER 26/1600Z. DURING THIS AFTERNOON...RAINFALL WILL BECOME
MODERATE TO HEAVY AT TIMES (LOWERING CIGS TWD 500 FT AGL) AND E-SE
WINDS WILL BECOME BREEZY WITH GUSTS AROUND 25-30 KT. KSBY WILL
BEGIN TO EXPERIENCE SIMILAR CONDITIONS AFTER 26/2000Z.
PRECIPITATION WILL COME TO AN END FROM SOUTHWEST TO NORTHEAST
THROUGH TUESDAY EVENING AS LOW PRESSURE MOVES NORTHEAST AND OUT OF
THE AREA AFTER MIDNIGHT. BREEZY WINDS OVERNIGHT WILL HELP TO SCOUR
OUT LOWER CIGS AND IMPROVE VISIBILITIES ONCE PRECIP COMES TO AN END.
&&
.MARINE...
SCA HEADLINES HAVE BEEN ADJUSTED TO BEGIN EARLY THIS MORNING WITH
THE EXCEPTION OF CURRITUCK SOUND AND NRN COASTAL WATERS WHERE
WINDS WILL NOT INCREASE UNTIL THIS AFTN. HAVE ALREADY BEGUN TO SEE
A SLIGHT INCREASE IN WINDS OVER THE SRN BAY AS HIGH PRESSURE NOW
RESIDES OVER NEW ENGLAND AND THE PRESSURE GRADIENT TIGHTENS IN
RESPONSE TO THE APPROACHING LOW PRESSURE SYSTEM TO THE SOUTHWEST.
EAST WINDS ARE GENERALLY AOB 15 KT...HOWEVER THEY WILL TURN SE
AND INCREASE THIS AFTN...GUSTING BTWN 25-40 KT (DEPENDING ON
LOCATION). SE WINDS WILL PEAK EARLY THIS EVENING...THEN BECOME SW
AND DECREASE AFTER MIDNIGHT TONIGHT. SEAS ARE GENERALLY 4-5 FT
EARLY THIS MORNING AND WILL ALSO INCREASE TO 7-10 FT DURING THE
AFTN AND OVERNIGHT AS LOW PRESSURE MOVES UP THE MID ATLANTIC
SEABOARD AND INTENSIFIES.
AS THE LOW MOVES NORTH OF AREA WATERS...WARM MARINE AIR CONTINUED
TO BE PULLED INTO THE STORM AND WILL ACT TO INHIBIT ADDITIONAL
MIXING IN THE WAKE OF THE LOW. AFTER THAT...A PROLONGED PERIOD OF
OFFSHORE WINDS PREVAILS WED THROUGH AT LEAST FRIDAY. WINDS WILL
INITIALLY BE WSW ON WED...THEN WNW THU INTO THE WEEKEND. THE
POTENTIAL FOR EXTENDED SCA FLAGS EXISTS DURING THIS TIME DUE TO A
LONG PERIOD OF LOW LEVEL CAA...RESULTING IN WIND SPEEDS AOA 20-25 KT
AT TIMES.
&&
.TIDES/COASTAL FLOODING...
TIDAL ANOMALIES ARE STILL RUNNING ABOUT 0.5 TO 1.0 FT ABOVE
NORMAL...ESPECIALLY DURING THE HIGH TIDE CYCLE TO OCCUR THIS
EVENING. OVERALL WATER LEVELS ARE EXPECTED TO STAY ABOUT 1-2 FT
BELOW MINOR FLOODING THRESHOLDS...BUT WILL NEED TO MONITOR LATEST
FORECASTS CLOSELY DUE TO INCREASING E-SE WINDS THIS AFTN AND
EVENING.
&&
.AKQ WATCHES/WARNINGS/ADVISORIES...
MD...NONE.
NC...NONE.
VA...NONE.
MARINE...SMALL CRAFT ADVISORY UNTIL 1 AM EST WEDNESDAY FOR ANZ635>638.
SMALL CRAFT ADVISORY UNTIL 10 AM EST WEDNESDAY FOR ANZ630>632-
634.
SMALL CRAFT ADVISORY FROM NOON TODAY TO 1 AM EST WEDNESDAY FOR
ANZ633.
SMALL CRAFT ADVISORY UNTIL 4 PM EST THIS AFTERNOON FOR ANZ650-
652-654.
GALE WARNING FROM 4 PM THIS AFTERNOON TO 1 AM EST WEDNESDAY
FOR ANZ650-652-654.
SMALL CRAFT ADVISORY UNTIL 1 AM EST THURSDAY FOR ANZ656.
SMALL CRAFT ADVISORY UNTIL 7 AM EST THURSDAY FOR ANZ658.
&&
$$
SYNOPSIS...MAM
NEAR TERM...JDM/MAM
SHORT TERM...MAM
LONG TERM...ALB
AVIATION...BMD
MARINE...BMD
TIDES/COASTAL FLOODING...AKQ
AREA FORECAST DISCUSSION
NWS GRAND RAPIDS MI
648 AM EST TUE FEB 26 2013
.SYNOPSIS...
ISSUED AT 324 AM EST TUE FEB 26 2013
A STORM SYSTEM GATHERING STRENGTH ACROSS ARKANSAS EARLY THIS MORNING
WILL APPROACH LOWER MICHIGAN THIS AFTERNOON AND EVENING.
PRECIPITATION WILL DEVELOP ACROSS THE AREA FROM SOUTH TO NORTH
DURING THE AFTERNOON AND EVENING HOURS. A MIXTURE OF RAIN...SNOW...
AND SOME SLEET WILL BE POSSIBLE AS PRECIPITATION DEVELOPS. ALL
PRECIPITATION WILL QUICKLY CHANGE OVER TO SNOW. SNOW ACCUMULATIONS
WILL RANGE FROM 2 INCHES OR SO UP NORTH...TO 6 INCHES DOWN SOUTH BY
WEDNESDAY MORNING. LIGHT SNOW WILL CONTINUE WEDNESDAY AND WEDNESDAY
NIGHT WITH ONLY LIGHT ADDITIONAL ACCUMULATIONS EXPECTED.
&&
.SHORT TERM...(TODAY THROUGH THURSDAY)
ISSUED AT 324 AM EST TUE FEB 26 2013
MAIN FOCUS OF THE FCST IS OBVIOUSLY THE INCOMING SYSTEM AND
EVALUATING WHETHER ANY ADJUSTMENTS ARE NEEDED TO THE GOING
HEADLINES. AT THIS TIME...WE WILL BE HOLDING ON TO THE ADVISORY AS
IT IS AS THERE IS NOT A GOOD REASON TO CHANGE THINGS FOR NOW.
THE LATEST MODEL RUNS FROM THE 00Z CYCLE ARE PRETTY MUCH MAINTAINING
GOOD CONTINUITY FROM THEIR PREVIOUS RUNS. WE ARE STILL EXPECTING A
NICE AND POSSIBLY HEAVY BURST OF PCPN INITIALLY BY MID AFTERNOON
DOWN SOUTH ALONG I-94...AND SPREADING NORTH INTO THE MID EVENING
HOURS TONIGHT. THIS BURST IS THE RESULT OF STRONG ISENTROPIC
ASCENT/MOISTURE TRANSPORT ALOFT OUT AHEAD OF THE SYSTEM AND
RESULTING STRONG FGEN DEVELOPING AS A RESULT. WE CONTINUE
TO SEE A GOOD CROSS-HAIRS SIGNATURE WHERE THE BEST LIFT OCCURS IN THE
DGZ. IN ADDITION...A WEAKNESS IN THE STABILITY DOES EXISTS WHICH
WILL ONLY ENHANCE THE BAND OF PCPN. IT SHOULD BE MENTIONED THAT A
GOOD PORTION OF THE STORM TOTALS ARE EXPECTED TO COME FROM THIS
HEAVY BURST THIS AFTERNOON/EVENING. LOW SNOW TO WATER RATIOS WILL
LIMIT SNOW ACCUMULATIONS SOME. THE HEAVIER BAND OF PCPN SHOULD
PRODUCE BRIEFLY HIGHER SNOW TO WATER RATIOS WITH THE DGZ AND LIFT
COINCIDING.
THE MAIN CONCERN IN THE WHOLE EVENT THAT WE ARE MONITORING IS THE
POTENTIAL FOR A LITTLE MORE POSSIBLE RAIN AT THE ONSET DOWN SOUTH. A
COUPLE OF THE MODELS...SPECIFICALLY THE NAM AND GEM ARE INDICATING A
BIT BETTER CHC OF RAIN DOWN SOUTH THIS AFTERNOON AND EARLY EVENING
BEFORE ALL PCPN CHANGES OVER TO SNOW DUE TO EVAPORATIVE COOLING. THE
GFS AND EURO EACH BRING SUFFICIENTLY DEEP WET BULB ZERO HEIGHTS
ALMOST TO I-94 BEFORE EVAPORATIVE COOLING WIPES THAT OUT BY MID
EVENING. WE ARE LEANING HEAVILY TOWARD THE GFS AND EURO AT THIS TIME
AS THEY HAVE BEEN VERY CONSISTENT. WE HAVE ADDED IN/MAINTAINED A CHC
OF RAIN ACROSS THE FAR SOUTH IN THE EVENT THAT THE WET BULB ZERO
HEIGHTS ARE JUST DEEP ENOUGH TO ALLOW FOR SOME RAIN. SLEET REMAINS
POSSIBLE STILL ALSO AT THE ONSET DOWN SOUTH WITH A WARM NOSE ALOFT
AND THEN A COLD LAYER BEFORE A SLIGHTLY ABOVE FREEZING SFC TEMP.
WE WILL SEE THE ISENTROPIC ASCENT BURST OF PCPN SHIFT NORTH AND EAST
THIS EVENING BEFORE WEAKENING AND MOVING OUT AS THE MAIN PUSH OF
WARMTH AND MOISTURE SHIFTS SE WITH THE TRANSFER OF ENERGY EXPECTED
TO TAKE PLACE THIS EVENING. WE STILL EXPECT TO SEE A LULL IN THE
SNOW BEFORE IT WILL PICK UP ONCE AGAIN SOME LATER IN THE EVENING AND
OVERNIGHT AS THE DEFORMATION ZONE/TROWAL MOVES INTO THE AREA. THE
SECOND ROUND IS EXPECTED TO BRING LIGHTER ACCUMULATIONS THAN THE
INITIAL BURST FOR MANY LOCATIONS. THERE WILL BE NO P-TYPE ISSUES
WITH THIS ROUND AS EVAPORATIVE COOLING WILL MAKE THE ENTIRE COLUMN
COLD ENOUGH FOR SNOW.
WE WILL SEE THE SNOW TAPER OFF SOME THEN FOR WED AND WED NIGHT.
HOWEVER WE WILL CONTINUE TO SEE INTERVALS OF LIGHT SNOW AS THE UPPER
LOW GETS HUNG UP TO OUR EAST AND WE WILL REMAIN CYCLONIC ALOFT. THIS
IS SOMEWHAT SIMILAR TO THE EVENT LATE LAST WEEK DUE TO THE UPPER
LOW. IT IS DIFFERENT IN THE SENSE THAT THERE WILL NOT REALLY BE A
LAKE CONTRIBUTION DUE TO H850 TEMPS NOT BEING COLD ENOUGH AND THAT
THE FLOW WILL REMAIN OFFSHORE THROUGH WED NIGHT. ACCUMULATIONS
SHOULD BE LIMITED TO AROUND AN INCH OR SO FOR EACH WED AND THEN
AGAIN WED NIGHT. THE UPPER LOW WILL PULL AWAY ON THU AND GRADUALLY
TAKE THE SNOW CHANCES EAST OF THE AREA THROUGH THE DAY.
.LONG TERM...(THURSDAY NIGHT THROUGH MONDAY)
ISSUED AT 324 AM EST TUE FEB 26 2013
FOR NOW I WILL CONTINUE OUR IDEA OF A PERIOD OF PRECIPITATION FREE
WEATHER FOR SOUTHWEST MICHIGAN FROM FRIDAY INTO MONDAY. TEMPERATURES
WILL BE COLDER THAN NORMAL DURING THIS TIME PERIOD.
MY CONFIDENCE IN THIS FORECAST IS A LITTLE LESS THAN YESTERDAY SINCE
EVEN THOUGH THE MODELS HAVE BEEN SOMEWHAT CONSISTENT WITH THE
LONG WAVE PATTERN FORECAST...THERE ARE NUMEROUS DETAIL ISSUES AS TO
HOW INDIVIDUAL SHORTWAVES ARE HANDLED AS THEY MOVE THROUGH THE MEAN
WESTERN RIDGE INTO THE CENTRAL GREAT LAKES.
TWO LARGE SCALE FEATURES WORK TOGETHER TO CREATE AN AMPLIFIED UPPER
AIR PATTERN OVER THE CONUS DURING THIS TIME PERIOD. THERE IS A
POWERFUL PACIFIC STORM APPROACHING THE DATELINE (AS I WRITE THIS)
THAT BOOTS THE SYSTEM ALREADY THERE DOWNSTREAM OVER THE WESTERN
RIDGE INTO WEST CENTRAL CONUS IN THE FRI/SAT TIME FRAME. SINCE THE
STORM HEADING TOWARD THE DATELINE IS POWERFUL STORM...IT ENDS UP
BUILDING THE WESTERN RIDGE EVEN STRONGER THAN IT CURRENTLY IS. THAT
HELPS TO CREATE MORE NORTHERLY FLOW AT MID AND UPPER LEVELS OVER
CENTRAL NORTH AMERICA. MEANWHILE THERE IS A LARGE BLOCKING UPPER
HIGH EAST OF GREENLAND THAT IS CURRENTLY RETROGRADING. THAT IS
FORCING ANY SYSTEMS SOUTH OF IT. THE COMBINATION OF THOSE TWO
SYSTEMS...ONE OVER THE NORTH ATLANTIC AND THE OTHER OVER THE NORTH
PACIFIC...WILL PROVIDE A STEADY SUPPLY OF COLD (BUT NOT ARCTIC) AIR
INTO EARLY NEXT WEEK DUE TO THE LARGELY NORTH NORTHWEST FLOW AT
UPPER LEVELS DURING THAT TIME.
ANOTHER ASPECT TO THIS IS THE EXTENSION OF THE HUDSON BAY HIGH INTO
LOWER MICHIGAN INTO THIS COMING WEEKEND. THAT CREATES A NORTH
NORTHEAST SURFACE WIND FLOW. THAT IN TURN WILL KEEP ANY LAKE EFFECT
ON THE WISCONSIN SIDE OF LAKE MICHIGAN INTO EARLY NEXT WEEK.
THE ONLY REAL ISSUE IS THAT THERE ARE SEVERAL MINOR SHORTWAVES
MOVING THROUGH THE UPPER LEVEL FLOW DURING THIS TIME PERIOD. IT IS
POSSIBLE IF ONE OF THOSE SHORTWAVES GOT A TOUCH MORE AMPLIFIED WE
COULD BE SEEING AND EXTEND PERIOD OF LIGHT SNOW. NOW THOUGH IT LOOKS
LIKE ANY SYSTEMS WILL STAY WEST AND SOUTH OF LOWER MICHIGAN...
BRINGING LARGELY DRY BUT COLD WEATHER.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z WEDNESDAY MORNING)
ISSUED AT 647 AM EST TUE FEB 26 2013
LITTLE QUESTION THE CURRENT VFR CIGS/VSBY WILL GO TO SOLID IFR
CIGS/VSBY BY 00Z WITH SNOW ACROSS ALL TAF SITES.
THE TIMING WAS FOR WHEN THE PRECIPITATION REACHES EACH TAF SITE
AND THE TIMING OF THE CHANGE FROM RAIN TO SNOW WAS BASED ON
COMBINATION OF THE HRRR AND 06Z NAM12 RADAR FORECASTS WITH SOME
CONSIDERATION TO HOW WELL THOSE FORECAST FIELDS MATCH THE CURRENT
PRECIPITATION PATTERN. BOTH ARE SIMILAR ON TIMING AND DO A GOOD
JOB OF MATCHING WERE THE PRECIPITATION HAS BEEN THE PAST FEW
HOURS. THE HRRR IS MUCH MORE RELUCTANT TO CHANGE THE RAIN TO
SNOW... IN FACT THE HRRR HAS NO SNOW OVER ANY PART OF THE CWA
THROUGH 00Z... IT SHOWS ALL RAIN. CURRENTLY (11Z) THE RAIN TO SNOW
LINE IS IN CENTRAL ILLINOIS... THE HRRR HAS IT EASTERN IOWA. THE
RAIN/SNOW LINE IS BETTER MATCHED ON THE NAM12 WHICH HAS IT WHERE
IT CURRENTLY IS. SO... I USED THAT FOR MY RAIN TO SNOW DECISION MAKING IN
THE TAFS. ONCE THE PRECIPITATION BEGINS... IT WILL QUICKLY LOWER
THE CEILING TO IFR AND WITH THE SLOW MOVEMENT OF THE SYSTEM THE
IFR CIGS/VSBY WILL CONTINUE THROUGH THE NIGHT INTO WEDNESDAY.
&&
.MARINE...
ISSUED AT 324 AM EST TUE FEB 26 2013
WE HAVE EXTENDED THE SMALL CRAFT ADVISORY OUT ANOTHER 24 HOURS
THROUGH 12Z THU. WINDS ARE EXPECTED TO REMAIN ABOVE 25 KNOTS AT
LEAST THROUGH THU MORNING...AND VERY LIKELY BEYOND THEN. WE STILL
CAN NOT RULE OUT SOME GALE GUSTS LATER TODAY AND TONIGHT...HOWEVER
IT SHOULD BE THE EXCEPTION RATHER THAN THE RULE DUE TO THE OFFSHORE
FLOW AND A LACK OF COLD AIR ADVECTION.
&&
.HYDROLOGY...
ISSUED AT 324 AM EST TUE FEB 26 2013
THE ONLY THING OF CONCERN IN HYDROLOGY REMAINS THE POTENTIAL FOR ICE
JAMS. THERE HAS BEEN NOTHING TO NOTE IN THE LAST COUPLE OF DAYS. WE
WILL CONTINUE TO MONITOR FOR ANY POTENTIAL PROBLEMS THAT MAY CROP UP
AS MILD TEMPS WORK ON ANY ICE ON THE RIVERS AND STREAMS.
&&
.GRR WATCHES/WARNINGS/ADVISORIES...
MI...WINTER WEATHER ADVISORY FROM 1 PM THIS AFTERNOON TO 6 AM EST
WEDNESDAY FOR MIZ064>067-071>074.
WINTER WEATHER ADVISORY FROM 4 PM THIS AFTERNOON TO 6 AM EST
WEDNESDAY FOR MIZ044>046-050>052-056>059.
LM...SMALL CRAFT ADVISORY UNTIL 7 AM EST THURSDAY FOR LMZ844>849.
&&
$$
SYNOPSIS...NJJ
SHORT TERM...NJJ
LONG TERM...WDM
AVIATION...WDM
HYDROLOGY...NJJ
MARINE...NJJ
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
621 AM EST TUE FEB 26 2013
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 357 AM EST TUE FEB 26 2013
00Z RAOBS/LATEST WV IMAGERY AND RUC ANALYSIS SHOW SPLIT FLOW PATTERN
ACRS NAMERICA...WITH THE UPR GRT LKS UNDER A POLAR JET STREAM WELL S
OF ARCTIC BRANCH IN CENTRL CANADA THAT HAS CONFINED THE BITTERLY
COLD ARCTIC AIR TO FAR NRN CANADA. AN ACTIVE SUBTROPICAL BRANCH
DOMINATES THE S HALF OF THE CONUS...WITH A POTENT DISTURBANCE MOVING
INTO THE LOWER-MID MS RIVER VALLEY. A DISTURBANCE WITHIN THE POLAR
BRANCH IS MOVING ACRS UPR MI EARLY THIS MRNG...BUT LIMITED MSTR
DEPTH PER 00Z GRB/APX RAOBS AND GENERAL LARGER SCALE ACYC FLOW
RELATED TO RDG AXIS EXTENDING WWD FM HI CENTER IN SE CANADA HAS
RESTRICTED ANY IMPACT TO AN AREA OF SC. THE BACK EDGE OF THIS CLD
AREA IS JUST INLAND FM THE W SHORE OF UPR MI CLOSER TO INCOMING AREA
OF DRY AIR DEPICTED ON THE 00Z INL/MPX RAOBS AND WHICH IS UNDER
DNVA/LARGE SCALE QVECTOR DVGC BEHIND THE SHRTWV. SKIES OVER FAR NW
WI/WRN LK SUP AND THE MN ARROWHEAD OF MOCLR...WHICH HAS ALLOWED SOME
FOG TO FORM WITH LGT WINDS. HI CLDS ON THE NRN EDGE OF THE
SUBTROPICAL BRANCH DISTURBANCE TO THE S ARE SPREADING SLOWLY NWD
THRU WI.
MAIN FCST CONCERNS TODAY ARE CLD TRENDS/IMPACT ON TEMPS. FOCUS FOR
TNGT SHIFTS TO WHETHER ANY PCPN ASSOCIATED WITH SRN BRANCH
DISTURBANCE WL IMPACT THE SRN CWA.
TODAY...POLAR BRANCH UPR RDG/DNVA/LARGE SCALE QVECTOR DVGC WL
DOMINATE UPR MI TODAY. AS THE SUBTROPICAL BRANCH SFC LO MOVES INTO
THE LOWER OH RIVER VALLEY BY 00Z WED...THE PRES GRADIENT WL TIGHTEN
OVER UPR MI TO THE WSW OF HI CENTERED IN SE CANADA...WITH AN INCRSG
ENE FLOW. ALTHOUGH THE LARGER SCALE NEGATIVE DYNAMICS WOULD INDICATE
A SLOW BREAKUP OF THE SC DOMINATAING MUCH OF THE CWA NOW...THIS LO
CLD IS WIDESPREAD TO THE E OF UPR MI THIS MRNG...THE SOURCE AIRMASS
FOR THE DVLPG E WIND. ON THE OTHER HAND...THE DIFFLUENT NATURE OF
THE LLVL FLOW AS WELL AS STRONG SUBSIDENCE FCST AT H925 SHOULD TEND
TO BREAK UP THE LO CLD. RECENT TRENDS SHOWN ON STLT IMAGERY/SFC OBS
CONFIRM THIS EXPECTATION. DIURNAL HEATING WITH INCRSG LATE FEB SUN
ANGLE WL ALSO TEND TO DISSIPATE THE SC OVER THE LAKES AS H85 TEMPS
ARE FCST TO BE ABOUT -4C...A TYPICAL EARLY SPRING SCENARIO. IN THIS
SCENARIO...SOME DIURNAL CU/SC WOULD TEND TO FORM OVER THE INTERIOR
FOLLOWING INITIAL CLRG. THE COVERAGE OF THIS CLD SHOULD BE LIMITED
BY THE RATHER LO INVRN BASE SHOWN ON NAM/GFS FCST SDNGS. MAINTAINED
OVERALL FLAVOR OF GOING FCST SHOWING A TERND FOR DECREASING CLDS
INTO THIS AFTN...WITH A BIT MORE CLD COVER OVER THE INTERIOR...
ESPECIALLY IN USPLOPE AREAS. MIXING TO H875 ON FCST SDNGS YIELDS HI
TEMPS CLOSE TO 40...MOST LIKELY IN AREAS OVER THE W THAT SEE MORE
SUNSHINE AND DOWNSLOPE IN LLVL ENE FLOW AWAY FM THE COOLING
INFLUENCE OF THE LKS. GOING FCST NEEDS ONLY MINOR ADJUSTMENTS.
TNGT...SUBTROPICAL BRANCH LO IS PROGGED TO MOVE NE INTO OH BY 12Z
WED. THE BULK OF THE NUMERICAL GUIDANCE SHOWS LGT QPF ON THE NW
FLANK OF THIS LO PRES BRUSHING JUST THE SE COUNTIES WITH SOME LGT
PCPN TOWARD 12Z WED...CONSISTENT WITH THE PASSAGE OF THE DEEP LYR
QVECTOR THRU LWR MI. DESPITE CYC NATURE OF THE INCRSG LLVL NE
FLOW...H85 TEMPS NO LOWER THAN ABOUT -5C AS WELL AS FCST DRY H85-7
LYR INDICATE THERE WL BE NO LK EFFECT/ENHANCED PCPN EVEN IF MORE SC
DVLPS IN THE UPSLOPE AREAS. OPTED TO RETAIN GOING SCHC POPS ONLY
CLOSE TO LK MI/BAY OF GREEN BAY.
.LONG TERM...(WEDNESDAY THROUGH MONDAY)
ISSUED AT 357 AM EST TUE FEB 26 2013
NOT MUCH IN THE WAY OF PRECIPITATION EXPECTED THROUGH THIS LONG TERM
PERIOD...WITH MARCH LIKELY COMING IN LIKE A LAMB /AS NOTED ON THE
PREVIOUS DISCUSSION/.
BY WEDNESDAY THE 500MB LOW WILL BE THE CLOSEST IT WILL GET TO THE
CWA...TRACKING FROM OHIO TO NE PENNSYLVANIA...SQUEEZING THE RIDGE
NORTH INTO ONTARIO. EXPECT NE FLOW AT THE SFC AND ALOFT WEDNESDAY.
THE 25/12Z CONTINUES TO SHOW A SOUTHERLY TREND TO THE TRACK...WITH A
DOUBLE BARREL LOW SPLITTING THE APPALACHIANS MERGING ACROSS THE NEW
ENGLAND STATES WEDNESDAY NIGHT. A MEER 24 HOURS AGO THE NAM SOLUTION
WAS FOR THE SURFACE LOW TO SWING ACROSS CENTRAL LOWER MICHIGAN...NOW
IT LOOKS TO BE MORE IN LINE IF NOT SLIGHTLY SLOWER THAN THE
ECMWF/GFS ON WEDNESDAY.
STRONG HIGH PRESSURE STRETCHING ACROSS NORTH CENTRAL CANADA ON
TUESDAY WILL PUSH INTO HUDSON BAY AND MANITOBA/ONTARIO
WEDNESDAY/WEDNESDAY NIGHT...WITH THE RIDGE EDGING ACROSS LAKE
SUPERIOR THURSDAY NIGHT THROUGH AT LEAST SUNDAY MORNING. WE STILL
EXPECT SOME BREEZY CONDITIONS NEAR THE LAKE SUPERIOR SHORELINE
WEDNESDAY THROUGH THURSDAY /PUSHING ACROSS MUCH OF CENTRAL UPPER
MICHIGAN DURING THE DAY THURSDAY/. WINDS WILL SLOWLY DIMINISH AS THE
LOW CONTINUES TO EXIT EAST AND THE SURFACE HIGH PUSHES OVERHEAD.
AS FOR THE CHANCE OF PRECIPITATION THROUGH THE PERIOD...IT IS PRETTY
MINIMAL. THE SYNOPTIC SNOW WILL ONLY CLIP AREAS NEAR LAKE MICHIGAN
WEDNESDAY INTO WEDNESDAY EVENING. EVEN WITH THE FAVORABLE UPSLOPE
WINDS OFF LAKE SUPERIOR...TEMPERATURES AT AND ABOVE THE SURFACE WILL
BE MARGINAL TO SUPPORT ANY ACCUMULATING SNOW SHOWERS.
COLDER AIR WILL FINALLY COME IN FOR THE END OF THE WORK WEEK...WITH
850MB TEMPERATURES FALLING TO AROUND -11C FRIDAY AFTERNOON...AND -12
TO -14C FRIDAY NIGHT THROUGH AT LEAST SUNDAY /WITH N-NE WINDS
CONTINUING THROUGH SATURDAY/.
THE 25/12Z ECMWF KEEPS THE RIDGE IN PLACE THROUGH TUESDAY...BECOMING
OUT OF PHASE WITH THE 25/18Z GFS BY MONDAY NIGHT /STRONG 1044MB HIGH
OVER NORTHERN MANITOBA AND ONTARIO...COMPARED TO THE 1005MB LOW
ACROSS ONTARIO/. WHILE THE 26/00Z GFS DID COME IT SLIGHTLY BETTER
AGREEMENT...IT JUST CAN NOT BEAT THE RUN TO RUN CONSISTENCY BEING
SHOWN BY THE ECMWF. CUT BACK THE SLIGHT CHANCE POPS GIVEN WITH A
CONSENSUS OF THE MODELS FOR DAY 6/MONDAY TO RIGHT ALONG THE
WISCONSIN BORDER...MINIMIZING THE INFLUENCE OF THE 26/00Z GFS RUN ON
THE POPS.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z WEDNESDAY MORNING)
ISSUED AT 620 AM EST TUE FEB 26 2013
ALTHOUGH SOME MRNG GROUND FOG/OCNLY LOWER VSBYS MAY IMPACT CMX/IWD
EARLY THIS MRNG AND BKN CIGS WL LINGER A GOOD PART OF THE DAY AT
SAW...EXPECT VFR CONDITIONS TO PREDOMINATE WITH HI PRES RDG IN
CONTROL. AS LO PRES MOVING TOWARD THE LOWER LKS CAUSES A CYC NE FLOW
TO STRENGTHEN TNGT...SOME MVFR CIGS ARE LIKELY WHERE THIS FLOW
MOISTENED BY LK SUP WL UPSLOPE AT IWD/SAW.
&&
.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 357 AM EST TUE FEB 26 2013
A RIDGE OF HIGH PRESSURE ACROSS LAKE SUPERIOR WILL PUSH NORTHWARD
TODAY...IN ADVANCE OF WEAKENING LOW PRESSURE SLIDING FROM SOUTHERN
MISSOURI THIS MORNING TO FAR SOUTHEASTERN LOWER MICHIGAN AND OHIO
WEDNESDAY MORNING...AND EXITING ACROSS NEW YORK WEDNESDAY NIGHT. AS
A RESULT...EXPECT A TROUGH OVER LAKE SUPERIOR WITH STEADY N-NE WINDS
FROM MID AFTERNOON THROUGH THE REST OF THE WORK WEEK. THE STRONGEST
WINDS...WITH A FEW GUSTS NEARING 35KTS CAN BE EXPECTED WEDNESDAY
INTO THURSDAY AS LAKE SUPERIOR BECOMES PINNED BETWEEN THE LOW
PRESSURE SYSTEM TO OUR SOUTHEAST AND STRONG HIGH PRESSURE EDGING IN
FROM THE NORTHWEST. GIVEN THE STRONGER WINDS AND COOLER AIR SLIDING
IN...FREEZING SPRAY WILL BE POSSIBLE. HIGH PRESSURE WILL WIN OUT
FRIDAY...WITH A RIDGE RESIDING ACROSS LAKE SUPERIOR THROUGH AT LEAST
SATURDAY NIGHT.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...KC
LONG TERM...KF
AVIATION...KC
MARINE...KF
AREA FORECAST DISCUSSION
NWS KANSAS CITY/PLEASANT HILL MO
908 AM CST Tue Feb 26 2013
.UPDATE...
/901 AM CST Tue Feb 26 2013/
Have adjusted POPs based on latest radar trends. The storm seems to
have peaked and we are currently seeing dry air entrain into the
system from east, associated with the dry slot. This led to more
spotty precipitation in our eastern zones. So pops have been
decreased some there for the rest of the day. The main deformation
area is rotating through western and northwestern Missouri. This
should continue to be the case through the early afternoon so have
increased precipitation chances in that area. The IR satellite
depiction shows cloud tops have been warming which indicates a
weakening trend in the storm. This has led to radar returns
diminishing in intensity as well. Overall, the heaviest snow over the
next several hours will be across our northwestern zones from Kansas
City northward.
CDB
&&
.DISCUSSION...
Today and Wednesday...
The ongoing winter storm continues to be the main focus for this
forecast issuance. Primary changes to the forecast are to increase
snow amounts in north central and northeast Missouri into the 10-12
inch range, with locally higher amounts possible. Snow totals have
also decreased across northwest Missouri, where snow may not start
until after sunrise and only a few inches of snow accumulation are
expected later this morning.
The deformation zone along the northeast side of a deepening surface
low has set up across the southeastern half of the forecast area,
and appears to be pivoting along a line from the southern KC metro
to Kirksville. The highest snowfall totals should occur within this
band and areas to the southeast, although melting and compaction may
work to decrease overall totals across the area. By 12z-15z, the
main PV anomaly will begin to kick east of the CWA, separating the
upper-level forcing from low- to mid-level frontogenesis and thus
likely decreasing snowfall rates/intensity by mid-morning. However,
at least some lift will linger in the trowal and support continued
light to moderate snowfall, especially over northeast and north
central Missouri. The RAP and latest NAM indicate that as the trowal
pivots northward this morning, light snowfall may finally edge into
the northwest corner of the CWA. Dynamics may start to weaken by the
time snowfall can start in the northwest and residence time over the
area will be much shorter, keeping snowfall totals in the 1-3 inch
range along and northwest of a line from St. Joseph to Sheridan MO.
A secondary wave will drop east southeast into southern portions of
the forecast area by late tonight, allowing some additional light
snowfall to form over northeast Kansas and west central Missouri.
This wave will wrap into the main upper low on Wednesday, allowing
light snowfall to shift eastward and eventually exit the region on
Wednesday afternoon. Additional snowfall amounts should be around an
inch or less, due to some depletion of low-level moisture and a lack
of any mesoscale features to enhance the weaker, broad-scale upper
forcing.
Temperatures today should be relatively steady throughout the day
and evening, dropping only a few degrees by tonight as slightly
cooler air filters in behind the low. Highs on Wednesday may rise a
few degrees in the northwest where a few breaks of sunshine and
lesser snow cover may allow for a bit more warming, but should hover
near freezing across the remainder of the area.
Laflin
Wednesday Night and Thursday...
The deep upper low responsible for our Tuesday winter storm will
have moved into the Mid Atlantic States during this period pulling
the extensive cloud shield with it. This should lead to at least a
partial clearing from west to east on Thursday. Temperatures will
remain below average as pronounced northerly fetch with weak high
pressure builds into the central CONUS.
Medium Range (Friday through Monday)...
The upper pattern will be characterized by a pronounced upper ridge
building eastward across the Rockies with a deepening trough over
from the TN into the Lower MS Valley. In between dry northwest flow
aloft will maintain well below average temperatures through Sunday.
Prefer to use the GFS Ensemble Mean h5 field for early next week due
to timing/evolution differences between the ECMWF and GFS of a fairly
strong upper wave dropping southeast through the Intermountain
Region Sunday night. This feature could reach the Central High
Plains on Monday with increasing warm air advection aiding
development of downstream precipitation which could affect the CWA
by Monday night. For now a model average works best with a moderate
increase in PoPs for Monday night.
MJ
&&
.AVIATION...
For the 12z TAFs: A band of moderate to heavy snow will continue to
pivot northward across the region this morning, resulting in LIFR
visibilities and IFR to LIFR ceilings. The snowfall intensity should
decline from southeast to northwest from late morning through the
early afternoon, gradually improving visibilities into the MVFR
category; however, ceilings will likely remain IFR through much of
the day. Winds will be gusty out of the north northwest through the
early afternoon, then will decrease gradually through the evening
and overnight hours.
Laflin
&&
.EAX WATCHES/WARNINGS/ADVISORIES...
MO...WINTER STORM WARNING until 3 PM CST this afternoon FOR MOZ004-
012>014-020>022-028>031-037>039-043>046-053-054.
WINTER STORM WARNING until 9 PM CST this evening FOR MOZ005>008-
015>017-023>025-032-033-040.
WINTER WEATHER ADVISORY until 3 PM CST this afternoon FOR
MOZ001>003-011.
KS...WINTER STORM WARNING until 3 PM CST this afternoon FOR KSZ025-
057-060-102>105.
&&
$$
WFO EAX
AREA FORECAST DISCUSSION
NWS KANSAS CITY/PLEASANT HILL MO
644 AM CST Tue Feb 26 2013
...UPDATED AVIATION DISCUSSION...
.DISCUSSION...
Today and Wednesday...
The ongoing winter storm continues to be the main focus for this
forecast issuance. Primary changes to the forecast are to increase
snow amounts in north central and northeast Missouri into the 10-12
inch range, with locally higher amounts possible. Snow totals have
also decreased across northwest Missouri, where snow may not start
until after sunrise and only a few inches of snow accumulation are
expected later this morning.
The deformation zone along the northeast side of a deepening surface
low has set up across the southeastern half of the forecast area,
and appears to be pivoting along a line from the southern KC metro
to Kirksville. The highest snowfall totals should occur within this
band and areas to the southeast, although melting and compaction may
work to decrease overall totals across the area. By 12z-15z, the
main PV anomaly will begin to kick east of the CWA, separating the
upper-level forcing from low- to mid-level frontogenesis and thus
likely decreasing snowfall rates/intensity by mid-morning. However,
at least some lift will linger in the trowal and support continued
light to moderate snowfall, especially over northeast and north
central Missouri. The RAP and latest NAM indicate that as the trowal
pivots northward this morning, light snowfall may finally edge into
the northwest corner of the CWA. Dynamics may start to weaken by the
time snowfall can start in the northwest and residence time over the
area will be much shorter, keeping snowfall totals in the 1-3 inch
range along and northwest of a line from St. Joseph to Sheridan MO.
A secondary wave will drop east southeast into southern portions of
the forecast area by late tonight, allowing some additional light
snowfall to form over northeast Kansas and west central Missouri.
This wave will wrap into the main upper low on Wednesday, allowing
light snowfall to shift eastward and eventually exit the region on
Wednesday afternoon. Additional snowfall amounts should be around an
inch or less, due to some depletion of low-level moisture and a lack
of any mesoscale features to enhance the weaker, broad-scale upper
forcing.
Temperatures today should be relatively steady throughout the day
and evening, dropping only a few degrees by tonight as slightly
cooler air filters in behind the low. Highs on Wednesday may rise a
few degrees in the northwest where a few breaks of sunshine and
lesser snow cover may allow for a bit more warming, but should hover
near freezing across the remainder of the area.
Laflin
Wednesday Night and Thursday...
The deep upper low responsible for our Tuesday winter storm will
have moved into the Mid Atlantic States during this period pulling
the extensive cloud shield with it. This should lead to at least a
partial clearing from west to east on Thursday. Temperatures will
remain below average as pronounced northerly fetch with weak high
pressure builds into the central CONUS.
Medium Range (Friday through Monday)...
The upper pattern will be characterized by a pronounced upper ridge
building eastward across the Rockies with a deepening trough over
from the TN into the Lower MS Valley. In between dry northwest flow
aloft will maintain well below average temperatures through Sunday.
Prefer to use the GFS Ensemble Mean h5 field for early next week due
to timing/evolution differences between the ECMWF and GFS of a fairly
strong upper wave dropping southeast through the Intermountain
Region Sunday night. This feature could reach the Central High
Plains on Monday with increasing warm air advection aiding
development of downstream precipitation which could affect the CWA
by Monday night. For now a model average works best with a moderate
increase in PoPs for Monday night.
MJ
&&
.AVIATION...
For the 12z TAFs: A band of moderate to heavy snow will continue to
pivot northward across the region this morning, resulting in LIFR
visibilities and IFR to LIFR ceilings. The snowfall intensity should
decline from southeast to northwest from late morning through the
early afternoon, gradually improving visibilities into the MVFR
category; however, ceilings will likely remain IFR through much of
the day. Winds will be gusty out of the north northwest through the
early afternoon, then will decrease gradually through the evening
and overnight hours.
Laflin
&&
.EAX WATCHES/WARNINGS/ADVISORIES...
MO...WINTER STORM WARNING until 3 PM CST this afternoon FOR MOZ004-
012>014-020>022-028>031-037>039-043>046-053-054.
WINTER STORM WARNING until 9 PM CST this evening FOR MOZ005>008-
015>017-023>025-032-033-040.
WINTER WEATHER ADVISORY until 3 PM CST this afternoon FOR
MOZ001>003-011.
KS...WINTER STORM WARNING until 3 PM CST this afternoon FOR KSZ025-
057-060-102>105.
&&
$$
WFO EAX
AREA FORECAST DISCUSSION
NWS KANSAS CITY/PLEASANT HILL MO
400 AM CST Tue Feb 26 2013
.DISCUSSION...
Today and Wednesday...
The ongoing winter storm continues to be the main focus for this
forecast issuance. Primary changes to the forecast are to increase
snow amounts in north central and northeast Missouri into the 10-12
inch range, with locally higher amounts possible. Snow totals have
also decreased across northwest Missouri, where snow may not start
until after sunrise and only a few inches of snow accumulation are
expected later this morning.
The deformation zone along the northeast side of a deepening surface
low has set up across the southeastern half of the forecast area,
and appears to be pivoting along a line from the southern KC metro
to Kirksville. The highest snowfall totals should occur within this
band and areas to the southeast, although melting and compaction may
work to decrease overall totals across the area. By 12z-15z, the
main PV anomaly will begin to kick east of the CWA, separating the
upper-level forcing from low- to mid-level frontogenesis and thus
likely decreasing snowfall rates/intensity by mid-morning. However,
at least some lift will linger in the trowal and support continued
light to moderate snowfall, especially over northeast and north
central Missouri. The RAP and latest NAM indicate that as the trowal
pivots northward this morning, light snowfall may finally edge into
the northwest corner of the CWA. Dynamics may start to weaken by the
time snowfall can start in the northwest and residence time over the
area will be much shorter, keeping snowfall totals in the 1-3 inch
range along and northwest of a line from St. Joseph to Sheridan MO.
A secondary wave will drop east southeast into southern portions of
the forecast area by late tonight, allowing some additional light
snowfall to form over northeast Kansas and west central Missouri.
This wave will wrap into the main upper low on Wednesday, allowing
light snowfall to shift eastward and eventually exit the region on
Wednesday afternoon. Additional snowfall amounts should be around an
inch or less, due to some depletion of low-level moisture and a lack
of any mesoscale features to enhance the weaker, broad-scale upper
forcing.
Temperatures today should be relatively steady throughout the day
and evening, dropping only a few degrees by tonight as slightly
cooler air filters in behind the low. Highs on Wednesday may rise a
few degrees in the northwest where a few breaks of sunshine and
lesser snow cover may allow for a bit more warming, but should hover
near freezing across the remainder of the area.
Laflin
Wednesday Night and Thursday...
The deep upper low responsible for our Tuesday winter storm will
have moved into the Mid Atlantic States during this period pulling
the extensive cloud shield with it. This should lead to at least a
partial clearing from west to east on Thursday. Temperatures will
remain below average as pronounced northerly fetch with weak high
pressure builds into the central CONUS.
Medium Range (Friday through Monday)...
The upper pattern will be characterized by a pronounced upper ridge
building eastward across the Rockies with a deepening trough over
from the TN into the Lower MS Valley. In between dry northwest flow
aloft will maintain well below average temperatures through Sunday.
Prefer to use the GFS Ensemble Mean h5 field for early next week due
to timing/evolution differences between the ECMWF and GFS of a fairly
strong upper wave dropping southeast through the Intermountain
Region Sunday night. This feature could reach the Central High
Plains on Monday with increasing warm air advection aiding
development of downstream precipitation which could affect the CWA
by Monday night. For now a model average works best with a moderate
increase in PoPs for Monday night.
MJ
&&
.AVIATION...
For the 06Z TAFs...IFR cigs/vis with light snow has moved into MCI
and MKC (will reach STJ by 08Z) and will persist through tomorrow
afternoon. The heaviest snow will come down during the early morning
hours at the terminals with vsbys occasionally reduced to a quarter
of a mile or less with LIFR and occasional VLIFR cigs. Snowfall
rates at times will be on order of 1-2+ inches thus making it
difficult to keep runways clear. Conds will improve somewhat by mid
morning when snow will become light and vsby improve to 2-3SM
however cigs will remain IFR through the afternoon. Snow will come
to an end tomorrow evening with IFR cigs continuing.
73
&&
.EAX WATCHES/WARNINGS/ADVISORIES...
MO...WINTER STORM WARNING until 3 PM CST this afternoon FOR MOZ004-
012>014-020>022-028>031-037>039-043>046-053-054.
WINTER STORM WARNING until 9 PM CST this evening FOR MOZ005>008-
015>017-023>025-032-033-040.
WINTER WEATHER ADVISORY until 3 PM CST this afternoon FOR
MOZ001>003-011.
KS...WINTER STORM WARNING until 3 PM CST this afternoon FOR KSZ025-
057-060-102>105.
&&
$$
WFO EAX
AREA FORECAST DISCUSSION
NWS BILLINGS MT
304 AM MST TUE FEB 26 2013
.SHORT TERM...VALID FOR TDY AND WED...
THE LARGE-SCALE FLOW WILL REMAIN UNSETTLED THE NEXT TWO DAYS...BUT
WE WILL ACTUALLY HAVE RELATIVELY MILD AND MAINLY QUIET WEATHER.
AS OF 10 UTC...THE DYNAMICS WITH THE WAVE CROSSING THE REGION HAVE
MAINLY GONE TO WASTE ON SATURATING THE MID- AND HIGH-LEVELS IN OUR
RELATIVELY DRY AIR MASS. THIS IS BEING AMPLIFIED BY WESTERLY WINDS
IN THE LOW- AND MID-LEVELS...WHICH IS YIELDING A CLASSIC DOWNSLOPE
SIGNATURE ON RADAR WITH ALL RETURNS EAST AND SOUTH OF BILLINGS. IT
THUS APPEARS THE SNOWFALL WITH THIS WAVE WILL BE EVEN LESS THAN WE
THOUGHT THE LAST FEW DAYS. SNOWFALL RATES WILL PROBABLY BE TOO LOW
TO CAUSE WIDESPREAD PROBLEMS...AND IN SOME CASES ROAD TEMPERATURES
WILL ALREADY BE BELOW 32 F WHEN /OR PERHAPS IF/ SNOWFALL BEGINS IN
PLACES LIKE SHERIDAN...THUS REDUCING TRAVEL IMPACTS. WE THUS CHOSE
TO CANCEL THE PREVIOUSLY-ISSUED WINTER WEATHER ADVISORY EARLY.
TODAY...BASED ON LINGERING FORCING...WE WILL HAVE CHANCE-TYPE POPS
IN PLACE FOR SPOTS LIKE SHERIDAN AND BROADUS...WITH LIKELY POPS IN
THE BIG HORN MOUNTAINS. HOWEVER...THAT MAY STILL BE TOO MUCH. EVEN
MANY RECENT RAP RUNS SUGGEST MINIMAL PRECIPITATION FOR THOSE AREAS
ONCE THEY GET PAST THE FIRST COUPLE FORECAST HOURS /WHEN THE MODEL
IS BEING NEGATIVELY-INFLUENCED BY WEIGHTING TO EARLY-MORNING RADAR
IMAGES THAT ARE OVERESTIMATING SURFACE PRECIPITATION/. WE CHOSE TO
CARRY A SLIGHT CHANCE OF SHOWERS IN MOST PLACES AFTER 18 UTC SINCE
FORECAST SOUNDINGS SHOW ENOUGH INSTABILITY FOR SHALLOW CONVECTION.
THE BOUNDARY LAYER MAY ACTUALLY BE WARM ENOUGH TO YIELD A MIX WITH
RAIN IF SOME CONVECTION FORMS. SPEAKING OF THAT WARMTH...OUR MILD
START AND MIXING BENEATH SOME MID-LEVEL COLD AIR ADVECTION WILL BE
ENOUGH TO PUSH HIGHS INTO THE 40S F AGAIN IN MANY PLACES. THE SAME
ENVIRONMENT WILL ALLOW ACCESS TO 30 KT OF WIND ALOFT TOO.
TONIGHT...LOW POPS ARE LINGERED THROUGH 06 UTC IN MOST AREAS...AND
IN FAR SOUTHEAST MT THROUGH THE NIGHT. THAT IS IN RESPECT TO SMALL
CAPE THAT LINGERS ON FORECAST SOUNDINGS INTO THE EVENING...AND THE
PASSAGE OF A SUBTLE 500-HPA SHORT WAVE TROUGH. NOTE THAT WE LEANED
ON 00 UTC BIAS-CORRECTED GFS GRIDDED MOS FOR LOWS TONIGHT AS THAT
GUIDANCE HAS RECENTLY PERFORMED VERY WELL 24 HOURS OUT.
WED AND WED NIGHT...BRIEF SHORT WAVE RIDGING WILL CROSS THE REGION
AHEAD OF ANOTHER WEAK 500-HPA TROUGH STAGED FOR WED NIGHT. WE HAVE
LOW POPS IN PLACE WED NIGHT FOR THAT FEATURE. CHANGES TO THIS TIME
FRAME INCLUDED 1/ LEVERAGING THE BIAS-CORRECTED MODEL CONSENSUS TO
INCREASE HIGHS ON WED...AND 2/ INCREASING WINDS AROUND BIG TIMBER.
THE LATTER CHANGE IS BASED ON AN INCREASING SURFACE GRADIENT WHICH
LOOKS FAVORABLE FOR WINDS CENTERED ON BIG TIMBER GIVEN A MAGNITUDE
OF AT LEAST 10 HPA FROM IDAHO FALLS TO LEWISTOWN. SCHULTZ
.LONG TERM...VALID FOR THU...FRI...SAT...SUN...MON...
MODELS IN GOOD AGREEMENT THURSDAY INTO SATURDAY. DISTURBANCE IN
NORTHWESTERLY FLOW WILL HAVE THE POTENTIAL FOR A FEW SNOW SHOWERS
ON THURSDAY...MAINLY IN THE MOUNTAINS. RIDGING DEVELOPS THURSDAY
AFTERNOON INTO SATURDAY...THOUGH PLENTY OF MID AND UPPER LEVEL
MOISTURE WILL CONTINUE TO FLOW OVER THE AREA. THIS MOIST FLOW WILL
BRING SNOW SHOWERS TO AREA MOUNTAINS THURSDAY NIGHT THROUGH FRIDAY
NIGHT...WITH LOWER ELEVATIONS STAYING DRY AND WARMING UP INTO THE
LOWER 50S BY FRIDAY AFTERNOON. WARM CONDITIONS WILL CONTINUE INTO
SATURDAY WITH HIGHS IN THE 45 TO 55 DEGREE RANGE DESPITE
CONSIDERABLE CLOUD COVER.
FORECAST FOR SUNDAY INTO THE MIDDLE OF NEXT WEEK IS MUCH LESS
CERTAIN WITH MODELS CONTINUING TO STRUGGLE WITH PACIFIC ENERGY AND
NORTHWESTERLY FLOW DURING THIS PERIOD. ECMWF HAD BEEN THE MOST
CONSISTENT MODEL THE PAST FEW DAYS BUT HAS CHANGED CONSIDERABLY
WITH THE LATEST RUN. THE GFS WHICH WAS THE DRIER AND WARMER OF THE
MODELS THE PAST FEW DAYS IS NOW THE COLD AND SNOW LEADER. MODELS
ARE ALSO STRUGGLING WITH THE POTENTIAL FOR MID WEEK COLD SURGE AS
THE GFS NOW TAPS THE HUDSON BAY LOW AND DRAGS CHUNK OF VERY COLD
AIR WHILE THE ECMWF WHICH DID THE SAME THE PAST FEW DAYS NOW
BLOCKS THIS COLD AIR FROM ADVECTING WESTWARD. AS A RESULT MADE
FEW CHANGES TO THE LATER EXTENDED AND KEPT BROADBRUSH CLIMO TYPE
POPS WITH TEMPERATURES TRENDING NEAR OR SLIGHTLY BELOW AVERAGE
AFTER SUNDAY. CHAMBERS
&&
.AVIATION...
VFR CONDITIONS WILL BE PREDOMINANT OVER THE AREA TODAY. A WEAK
SYSTEM WILL MOVE OUT OF EASTERN ZONES THIS MORNING WITH ISOLATED
TO SCATTERED SNOW SHOWERS IN ITS WAKE CONTINUING INTO THIS
EVENING. LOCAL MVFR CONDITIONS CAN BE EXPECTED NEAR SNOW SHOWER
ACTIVITY. OCCASIONAL MOUNTAIN AND PASS OBSCURATION CAN BE EXPECTED
TODAY. NORTHWEST WINDS AT 10 TO 20 KTS ARE FORECAST FOR ALL AREAS
TODAY. CHAMBERS
&&
.PRELIMINARY POINT TEMP/POPS...
TDY WED THU FRI SAT SUN MON
-------------------------------------------------------
BIL 043 021/042 024/041 030/049 034/054 035/048 031/037
2/W 20/U 21/B 11/E 00/B 13/W 43/J
LVM 035 017/039 021/040 023/046 027/048 029/044 025/033
2/J 11/N 21/B 11/E 11/B 24/W 43/J
HDN 042 019/041 020/039 027/046 033/051 033/048 030/036
3/W 20/U 21/B 11/B 00/B 13/W 33/J
MLS 047 025/044 024/043 027/050 033/053 034/050 031/037
2/J 20/B 11/B 11/B 10/B 02/W 33/J
4BQ 040 021/040 018/039 025/045 032/050 031/047 030/037
4/J 30/B 11/B 11/B 10/B 02/W 33/J
BHK 045 024/037 020/039 024/045 030/047 031/046 028/035
2/J 21/B 11/B 11/B 10/B 02/W 33/J
SHR 037 011/035 012/036 021/042 028/048 029/047 027/034
4/J 30/U 11/B 11/B 00/U 03/J 43/J
&&
.BYZ WATCHES/WARNINGS/ADVISORIES...
MT...NONE.
WY...NONE.
&&
$$
WEATHER.GOV/BILLINGS
AREA FORECAST DISCUSSION
NWS GREENVILLE-SPARTANBURG SC
910 AM EST TUE FEB 26 2013
.SYNOPSIS...
STRONG LOW PRESSURE WILL MOVE FROM ARKANSAS TO KENTUCKY TODAY WHILE
DRAGGING A WARM FRONT NORTH TOWARD OUR AREA. EXPECT THE WARM FRONT
TO REACH VIRGINIA LATER TONIGHT. A COLD FRONT WILL CROSS OUR REGION
FROM THE NORTHWEST LATE WEDNESDAY.
&&
.NEAR TERM /THROUGH TONIGHT/...
900 AM UPDATE...BACK EDGE OF HEAVIER PCPN WILL BE NEAR DRY SLOT
EVIDENT ON WV IMAGERY. SFC OBS AND RADAR INDICATING SOME SCATTERED
SHOWERS ARE PRESENT BEHIND THE BACK EDGE. ALSO NOTING RAP SOUNDINGS
WHICH STILL SHOW INSTABILITY ABOVE WARM NOSE UNTIL MIDLEVEL COLD
ADVECTION GETS GOING THIS AFTN. THUS MAINTAINED CHC POPS BEHIND THE
SOLID PCPN SHIELD AS WELL AS THUNDER WORDING FROM MRNG PACKAGE.
REVISED TEMP TRENDS TO SLOW WARMING A BIT OVER THE NRN PIEDMONT
WHERE LIGHT ICE ACCUM STILL OCCURRING...PUTTING TEMPS MORE IN LINE
WITH 06Z NAM WHICH VERIFIED BETTER EARLIER THIS MRNG. ALLOWED WINTER
HEADLINES TO EXPIRE OVER THE SW MTNS WHERE TEMPS HAVE MOSTLY WARMED
ABV 0C...BUT EXTENDED BY ONE HOUR THE WINTER STORM WRNG UP NORTH AND
ALSO THE FZRA ADVY FOR THE FOOTHILLS THAT PREVIOUSLY EXPIRED AT 14Z.
PREV DISCUSSION...AS OF 400 AM...THE COMPLEX OCCLUDED LOW AND WEDGE
COMBO SYSTEM IS LIVING UP TO AND SURPASSING EXPECTATIONS A LITTLE
THIS MORNING. THE COOLING ACROSS THE NC MTNS AND THE AMOUNT OF
PRECIP EXPECTED THE NEXT SEVERAL HRS WILL COMBINE TO GIVE A GOOD
AMOUNT OF -FZRA ACROSS THE CENTRAL MTNS AND HIGHER ELEV OF THE SRN
FOOTHILLS...ALONG WITH THE ESCARPMENT AREA NEAR THE SC/NC BORDER.
STILL EVALUATING THE NRN MTNS AND HIGH ELEV NRN FOOTHILLS FOR A
POSSIBLE WARNING UPGRADE...BUT FOR NOW WILL COUNT OF THE PRECIP/ICE
ACCUMS REMAINING THE HIGHEST ACROSS THE AREAS TO THE SOUTH WHERE THE
BEST LIFT AND ISENT OMEGA EXIST. ALSO...WILL ADD A FREEZING RAIN
ADVISORY FOR AREAS EAST OF THE MTNS ACROSS THE NRN/SRN FOOTHILLS AND
THE NC PIEDMONT WEST OF THE I-77 CORRIDOR.
THE MODELS ARE DOING AN ADEQUATE JOB WITH THE DYNAMICS OF THIS
SYSTEM THROUGH THE NEAR TERM AND GIVE GOOD CONFIDENCE WITH THE
WARMING TAKING OVER THE LLVLS BY 14Z OR SO AND CHANGING THE MAJORITY
OF LOCALES TO ALL -RA. HOWEVER...THERE MAY BE SOME LINGERING POCKETS
OF -FZRA ACROSS ISOL MTN VALLEYS THROUGH LATE MORNING. HAVE NOTICED
THE WETBULB FREEZING ZONE EXPANDING IN COVERAGE THIS MORNING INTO
THE UPSTATE AND THREATENING AREAS AROUND CLT AND THE I-77. THIS WILL
BE MONITORED FOR A POSSIBLE FZRA ADVISORY INCLUSION.
THE HIGH WIND WARNING AND ADVISORY ACROSS THE WRN MTNS STILL LOOKS
GOOD. THE P/GRAD IS SHOWING AN 8 MB P/GRAD THROUGH 12Z AND THE LLJ
IS PROGGED TO STRENGTHEN TO AROUND 55 KTS ACROSS THE HIGHER
ELEVATIONS THROUGH THIS TIME AS WELL. NO ADJUSTMENTS WILL BE MADE TO
THIS PRODUCT.
THE DRY SLOT WORKS IN THIS AFTERNOON AND CLOUDS PRECIP WILL BE QUICK
TO END ACROSS THE SW/RN ZONES...HOWEVER THE NE/RN SECTIONS WILL HOLD
ONTO PRECIP THROUGH THE AFTERNOON. THE WEDGE ALSO BEGINS TO BREAK
DOWN AROUND NOON AND A WELL DEFINED TMB WILL DEVELOP WHILE A TRIPLE
POINT LOW TRAVERSES OVERHEAD. THUS...THUNDER HAS BEEN MAINTAINED IN
THE GRIDS BEGINNING ISOL AROUND 17Z AND CHANCE TSTMS DURING THE
AFTERNOON ACROSS THE ERN THIRD OF THE CWFA. NOT EXPECTING REALLY
DEEP OR OVERLY ORGANIZED CONVECTION...BUT WITH BULK SHEAR LEVELS
AROUND 70 KTS THERE COULD BE SOME WIND ISSUES WITH SOME OF THESE
LINES.
&&
.SHORT TERM /WEDNESDAY THROUGH THURSDAY NIGHT/...
AS OF 330 AM EST TUESDAY...AS WE HEAD TOWARD MARCH...IT LOOKS LIKE
WE ARE HEADING TOWARD WINTER...AT LEAST OVER THE NC MTNS NEAR THE TN
BORDER. WEDNESDAY WILL SEE THE UPPER LOW MOVING SLOWLY OVER THE
UPPER OH VALLEY. THIS WILL KEEP THE FLOW MORE SW TO W ACROSS THE
WESTERN CAROLINAS DURING MOST OF THE DAY DELAYING THE ARRIVAL OF THE
REALLY COLD AIR. HOWEVER...A LARGE VORT LOBE SHOULD PINWHEEL AROUND
THE UPPER LOW AND CROSS THE FCST AREA DURING THE LATE AFTERNOON AND
EARLY EVENING. THAT FEATURE WILL BE THE VANGUARD OF THE COOLER AIR
AND WILL TURN THE FLOW MORE NORTHWESTERLY WEDNESDAY NIGHT. THIS WILL
SERVE TO CRANK UP THE NW FLOW SNOW MAKING MACHINE. POP WAS RAMPED UP
INTO THE LIKELY RANGE NEAR THE TN BORDER AND KEPT THERE THROUGH
THURSDAY NIGHT AS FLOW AND MOISTURE REMAIN VERY FAVORABLE FOR THE
PRODUCTION OF SNOW SHOWERS. ACCUMULATIONS COULD END UP BEING
SIGNIFICANT IN THE FAVORABLE UPSLOPE AREAS NEAR THE TN BORDER...BUT
THE DURATION WILL BE LONG ENOUGH THAT OUR WARNING CRITERIA MIGHT NOT
BE MET. WILL NOT ISSUE A WATCH FOR THIS EVENT BECAUSE OF THE
DURATION V. ACCUM ISSUE...BUT PLAN TO HIT IT HARD IN THE HWO. SOME
OF THE SNOW SHOWERS SHOULD REACH A BIT DEEPER INTO THE MTNS THURSDAY
NIGHT WHEN MOISTURE IS A BIT DEEPER. E OF THE MTNS...IT SEEMS
DOUBTFUL THAT ANY SHOWERS WILL BREACH CONTAINMENT AND SURVIVE E OF
THE BLUE RIDGE. INSTEAD...IT SHOULD BE DRY WITH A PARTLY
CLOUDY/MOSTLY CLEAR SKY...WITH TEMPS A BIT ABOVE NORMAL WEDNESDAY
AND THEN BELOW NORMAL THURSDAY AS THE COLDER AIR REALLY TAKES HOLD.
&&
.LONG TERM /FRIDAY THROUGH MONDAY/...
AS OF 300 AM EST TUESDAY...AS THE DEEP LOW PRESSURE SYSTEM MOVES
FARTHER OFFSHORE FROM LONG ISLAND ON FRIDAY...LOW LEVEL MOISTURE
WILL CONTINUE TO BANK UP AGAINST THE TN AND NC BORDER. THE
NORTHWEST FLOW FROM ACROSS KY AND TN WILL CONTINUE TO PRODUCE
UPSLOPE SNOW SHOWERS FRIDAY AND FRIDAY NIGHT. MEDIUM RANGE MODELS
AGREE ON A DISTURBANCE ROUNDING THE BASE OF THE 500MB TROUGH ON
SATURDAY WITH BROADER ENHANCEMENT OF MOSTLY LIGHT PRECIP ACROSS OUR
REGION. GFS HAS A 536 DECIMETER LOW CENTERED OVER THE SMOKIES AT 18Z
SATURDAY WITH A TENTH OR LESS 6-HOUR PRECIP EXTENDING OVER TO CLT.
THE NEW ECMWF CLOSES A LOW ON FRIDAY AS IT CROSSES TN AND THEN OPENS
IT ONCE IT IS OVER THE NC MTNS AT 18Z SATURDAY. THEREFORE THE TIMING
IS IN SYNC. ECMWF PRECIP IS VERY LIGHT...0.01 TO 0.03 IN 6 HOURS.
AS THIS FEATURE PASSES EAST OF OUR AREA...PRECIP ENDS EAST OF THE
MTNS SATURDAY NIGHT AND SUNDAY AND LIGHT UPSLOPE SNOW SHOWERS COME
TO AN END SUNDAY EVENING ALONG THE NC AND TN BORDER. MOST OF THE
GUIDANCE TONIGHT HAS INCREASING TEMPS BY ONE TO 3 DEGREES...BUT WITH
THE DEPTH OF THE TROUGH AND ALL OTHER LOGICAL METEOROLOGY IT SEEMS
SENSIBLE TO EVEN LOWER TEMPS A DEGREE OR TWO OVER THE WEEKEND.
AFTER THE TROUGH MOVES OFF THE EAST COAST SUNDAY NIGHT...A SHALLOW
RIDGE BUILDS OVER OUR AREA FOR MONDAY RESULTING IN SLIGHTLY HIGHER
THICKNESSES AND A BIT MILDER UNDER PLENTY OF SUNSHINE. EVEN WITH
THIS SLIGHT WARM UP...TEMPS WILL STILL BE ABOUT 8 TO 10 DEGREES
BELOW NORMAL TO START NEXT WEEK.
&&
.AVIATION /14Z TUESDAY THROUGH SATURDAY/...
AT KCLT...EXPECT THE PRECIP TO REMAIN ALL RAIN AT KCLT THIS MORNING
WITH NO GOOD COOLING TW UPSTREAM. THE PRECIP SHOULD HANG OUT FOR
MOST OF THE DAY AS A TRIPPLE POINT LOW CROSSES AND ENHANCES THE
CONVECTIVE POTENTIAL. DRY SLOT WORKS IN LATE AS THE WEDGE BOUNDARY
LIFTS NORTH...BUT CLOUDS WILL LIKELY HANG TOUGH IN THE MVFR RANGE
THIS EVENING AS DISSIPATING WEDGE MOVES SLOWLY. VFR CONDS ARE
EXPECTED AFT 02Z.
ELSEWHERE...PERIODS OF -FRZA WILL BE EXPERINCED AT KAVL AND MORE
CONTINUOUS -FZRA AT KHKY THROUGH 14Z OR SO. IMPROVING CONDS TO
MVFR/VFR ARE EXPECT AROUND 18Z EXCEPT FOR KHKY AS DRY SLOT WORKS IN
AND MOIST WEDGE LIFTS NE. WITH THE P/GRAD MAINTAINED AND EVEN
TIGHTENING A LITTLE THROUGH 18Z KAVL WILL CREATE THE POSSIBILITY OF
A WIND SHEAR CONCERN BTW 15Z AND 18Z.
OUTLOOK...DRY AIR ADV AND CLEARING SKIES WILL CONTINUE WED NIGHT
WITH VFR CONDS EXPECTED THROUGH THURSDAY EAST OF THE MOUNTAINS. SOME
POTENTIAL EXISTS FOR MVFR ACROSS THE NC MTNS WITH SNOW SHOWERS MID
TO LATE WEEK.
CONFIDENCE TABLE...
14-20Z 20-02Z 02-08Z 08-14Z
KCLT HIGH 94% HIGH 96% HIGH 90% HIGH 96%
KGSP MED 79% HIGH 90% HIGH 90% HIGH 98%
KAVL HIGH 80% MED 68% HIGH 86% HIGH 91%
KHKY HIGH 85% HIGH 94% HIGH 84% HIGH 90%
KGMU MED 79% HIGH 88% HIGH 90% HIGH 98%
KAND HIGH 88% MED 75% HIGH 96% HIGH 96%
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...HIGH WIND WARNING UNTIL 6 PM EST THIS EVENING FOR NCZ033-
048>052-058-059.
WIND ADVISORY UNTIL 6 PM EST THIS EVENING FOR NCZ033-048>052-
058-059.
WINTER STORM WARNING UNTIL 10 AM EST THIS MORNING FOR NCZ033-
049-050-501-503-505.
FREEZING RAIN ADVISORY UNTIL 10 AM EST THIS MORNING FOR
NCZ035>037-056-057-068-069-502-504-506-508-510.
SC...NONE.
&&
$$
SYNOPSIS...DEO
NEAR TERM...SBK/WIMBERLEY
SHORT TERM...PM
LONG TERM...DEO
AVIATION...SBK
AREA FORECAST DISCUSSION
NWS GRAND JUNCTION CO
1022 AM MST TUE FEB 26 2013
.UPDATE...
ISSUED AT 1021 AM MST TUE FEB 26 2013
SPOTTER REPORTS FROM THE GRAND MESA HAVE NOW REACHED A FOOT IN A
FEW SPOTS WITH SEVERAL SNOTELS APPROACHING 8 TO 10 INCHES AND
HEAVY SNOW CONTINUES TO FALL. LIGHT NORTHERLY COMPONENT TO LOW
LEVEL WIND FIELDS HELPING TO FUEL THIS REGION WITH PLENTY OF
MOISTURE. WITH TEMPS RIGHT IN THE DENDRITIC GROWTH ZONE...VERY
EFFICIENT SNOW PRODUCTION WILL CONTINUE FOR AT LEAST A FEW HOURS.
HAVE UPGRADED THE WINTER WEATHER ADVISORY TO A WINTER STORM
WARNING AND BOOSTED AMOUNTS EVEN HIGHER...WITH LOCAL ACCUMULATIONS UP
TO 20 INCHES NOT OUT OF THE QUESTION.
SNOW HAS TAPERED OFF IN THE MONTROSE AREA...BUT SCATTERED SHOWERS
WILL BE REDEVELOPING AND MOVING THROUGH LATER TODAY AND THIS
EVENING. JUST TO THE EAST OF MONTROSE ALONG HIGHWAY 50...SNOW
CONTINUES TO FALL OVER THE CERRO SUMMIT AREA AND EAST INTO
GUNNISON. SO TRAVEL WILL REMAIN HAZARDOUS AND HIGHLIGHTS WILL
REMAIN IN EFFECT.
AND FINALLY...SNOW CONTINUES TO FALL ALONG THE INTERSTATE 70
CORRIDOR AND SEVERAL ACCIDENTS...INCLUDING ROLLOVERS HAVE BEEN
REPORTED. IMPACT ON THIS HIGHLY TRAVELLED CORRIDOR REMAINS HIGH
AND WILL CONTINUE THE HIGHLIGHTS THROUGH THIS AFTERNOON.
UPDATE ISSUED AT 813 AM MST TUE FEB 26 2013
IMPACT BASED ADVISORIES HAVE BEEN ISSUED FOR SEVERAL OF THE LOWER
VALLEYS THIS MORNING AS LIGHT SNOW CONTINUES TO HAMPER THE MORNING
COMMUTE. SNOW WILL BECOME MORE SCATTERED IN NATURE THIS THIS
AFTERNOON...BUT CONVECTIVE ELEMENT WILL ENHANCE
SHOWERS...RESULTING IN LOCALIZED HEAVY SNOWFALL. SO HAVE CARRIED
THE VALLEY HIGHLIGHTS THROUGH LATE THIS AFTERNOON AND EVENING
BASED ON LOCATION. IN ADDITION...AREA OF CONVERGENCE SETTING UP
ACROSS THE SAN JUANS AND LIGHT SNOW CONTINUES TO DRAG SOUTH INTO
THE NORTHWEST SAN JUANS. BANDING PRECIP ALONG THE UNCOMPAHGRE
PLATEAU SHIFTS SLOWLY SOUTH AND WILL PROVIDE ADDITIONAL SNOWFALL
THROUGH LATE THIS MORNING. LIGHT NORTHERLY COMPONENT TO BOUNDARY
LAYER WINDS WILL KEEP DRIVING MOISTURE INTO THE GORGE SOUTH OF
OURAY...RESULTING IN LOCALLY HEAVY SNOWFALL. AMOUNTS MAY EXCEED 6
INCHES IN THIS AREA AND LOW END ADVISORY APPEARS JUSTIFIED. PRECIP
WINDS DOWN LATER THIS AFTERNOON AND OVERNIGHT FROM SOUTHWEST TO
NORTHWEST AS THE MAIN UPPER LEVEL LOW LIFTS OUT INTO THE PLAINS.
ZONES HAVE BEEN UPDATED WITH NEW SNOW TOTALS AND POPS.
UPDATE ISSUED AT 621 AM MST TUE FEB 26 2013
GRID UPDATE TO BOOST POPS WITH WIDESPREAD SNOW OCCURRING BENEATH
THE ENHANCED CLOUD OVER NW AND WEST CENTRAL COLORADO. TROUGH AXIS
IS OVER ERN UTAH AT 13Z...BUT UPPER CIRCULATION IS PROGGED BY THE
13KM RAP MODEL TO BE CENTERED OVER THE NWRN SAN JUAN MOUNTAINS BY
EARLY AFTERNOON. THIS AREA WILL NEED TO BE MONITORED AS NORTHWEST
FLOW AND NEGATIVE EQUIVALENT POTENTIAL VORTICITY SUGGEST BANDS OF
SNOW MAY BE TRAINING INTO THE GORGE. CURRENTLY ON THE RADAR...ONE
BAND OF SNOW IS TRYING TO BECOME ESTABLISHED ALONG THE UNCOMPAHGRE
PLATEAU. A WINTER WEATHER ADVISORY MAY BE NEEDED FOR ZONE 18.
REMAINDER OF THE FORECAST AREA APPEARS ON TRACK WITH SNOW BEGINNING
TO SPREAD OVER THE ELK MOUNTAINS TOWARD THE GORE RANGE.
&&
.SHORT TERM...(TODAY THROUGH WEDNESDAY)
ISSUED AT 355 AM MST TUE FEB 26 2013
THE NEXT WEATHER MAKER IN THE FORM OF AN OPEN TROUGH HAS BEGUN TO
MOVE INTO THE AREA EARLY THIS MORNING. CLOUDS HAVE INCREASED AND
LOWERED AHEAD OF THIS WAVE...WITH RADAR ECHOES REFLECTING THIS
TREND. ALSO SINCE AROUND 1 AM MST...K3MW IN THE PARK RANGE HAS
REPORTED SNOW...AND EXPECT SHOWERS HAVE DEVELOPED AT OTHER
NORTHERN MOUNTAIN LOCATIONS AS WELL.
THE LOW CENTER WILL DROP FROM THE NORTHERN ROCKIES SOUTH-SOUTHEAST
ACROSS WY BY MID-MORNING...AND OVER NORTHWEST CO BY MIDDAY. ALSO A
NOT VERY DISTINCT SURFACE FRONT AHEAD OF THE UPPER LEVEL TROUGH
WILL SEEP OVER THE AREA FROM NORTHWEST TO SOUTHEAST EARLY TODAY.
AS A RESULT SNOW WILL CONTINUE TO SPREAD IN FROM THE NORTHWEST
THROUGH THE NEXT 3-12 HOURS. BY DAYLIGHT...SNOW SHOULD BE
WIDESPREAD ACROSS THE NORTHERN MOUNTAINS AND WILL FILL INTO THE
WEST-CENTRAL CO MOUNTAINS BY MID MORNING. SNOW WILL CONTINUE
THROUGH THE AFTERNOON AS THE -32/-33 COLD POOL AT 500 MB MOVES
OVER THE AREA. THE PRESENT FORECAST LOOKS ON TRACK WITH LOW-END
ADVISORY AMOUNTS IN THE NORTHERN AND WEST-CENTRAL MOUNTAINS...
FAVORING THE NORTHWEST FACING SLOPES. OTHER MOUNTAIN AREAS SHOULD
SEE A PERIOD OF SNOW...BUT WITH LIGHTER ACCUMULATIONS. VALLEYS
WILL SEE ISOLATED TO SCATTERED SNOW SHOWERS...WITH BETTER COVERAGE
OVER MUCH OF THE NORTH...AND LITTLE TO NO SHOWERS ALONG OUR WEST
AND SOUTHWEST BORDERS. BY LATE AFTERNOON ACTIVITY WILL BEGIN TO
DIMINISH IN THE WESTERN VALLEYS AS DRIER AIR MOVES IN. HOWEVER
SNOW WILL CONTINUE IN THE CO MOUNTAINS THROUGH THE EVENING THE AS
THE COLD AIR ALOFT REMAINS IN PLACE...AND THE FAVORED DENDRITIC
GROWTH LAYER WILL REMAIN SATURATED AND NEAR MOUNTAIN TOP LEVEL.
THEN BY LATE TONIGHT THE NORTH FLOW WILL CONTINUE TO PRODUCE LIGHT
SNOW ALONG THE NORTH SLOPES OF THOSE FAVORED NORTH AND CENTRAL
MOUNTAINS. THIS ACTIVITY WILL GRADUALLY DIMINISH TOWARDS SUNRISE
WED.
ONE AREA THAT SHOULD BE WATCHED IS THE UNCOMPAHGRE GORGE AT AND
NEAR OURAY CO. THIS AREA COULD PICK UP SOME DECENT ACCUMULATIONS
AS THE FLOW TURNS AROUND TO NORTH LATER TODAY THROUGH THIS
EVENING. HOWEVER...I CHOSE NOT TO INCLUDE CO ZONE 18 IN THE
ADVISORY AS THE DURATION WILL BE SHORT...AND THE HEAVIER
ACCUMULATIONS ARE EXPECTED TO BE LOCALIZED.
ANY REMAINING SHOWERS IN THE NORTHERN MOUNTAINS WILL QUICKLY WIND
DOWN THROUGH THE MORNING ON WED...WITH ONLY A FEW LINGERING BEYOND
MIDDAY NEAR THE CONTINENTAL DIVIDE.
BELOW NORMAL TEMPERATURES WILL CONTINUE.
.LONG TERM...(WEDNESDAY NIGHT THROUGH MONDAY)
ISSUED AT 355 AM MST TUE FEB 26 2013
RIDGE AMPLIFIES OVER THE WEST COAST STATES WEDNESDAY NIGHT INTO
THURSDAY NIGHT...BUT THE GFS AND TO A LESSER EXTENT THE SREF
INDICATE A DISTURBANCE WILL STREAM OVER THE NRN DIVIDE MOUNTAINS FOR
A CHANCE OF SNOW. THE ECMWF APPEARS TO BE TRENDING THIS DIRECTION
SO THE CHANCE POPS APPEAR WARRANTED. THIS WOULD BE A FAST MOVING
DISTURBANCE AND ANY SNOWFALL WILL BE LIGHT.
IN THE BIGGER PICTURE...A WARMING TREND WILL OCCUR THIS UPCOMING
WEEKEND AS A WARM RIDGE MOVES EAST ACROSS THE INTERMOUNTAIN WEST AND
ROCKY MOUNTAIN STATES ON SATURDAY AND SUNDAY. EXPECT WARMING TEMPS
AT ALL LOCATIONS...OR SLIGHTLY ABOVE AVERAGE COMPARED TO CLIMO.
RECENT TEMPS HAVE BEEN BELOW NORMAL...SO THIS WARMING WILL FEEL MORE
SIGNIFICANT THAN COMPARED TO CLIMO.
FORECAST CONFIDENCE DIMINISHES SUNDAY NIGHT AND MONDAY AS A
SIGNIFICANT SHORT WAVE PUNCHES ACROSS THE PACIFIC NORTHWEST AND NRN
INTERMOUNTAIN REGION. SOME ENTRAINMENT OF SUBTROPICAL MOISTURE IS
POSSIBLE AHEAD OF THIS FEATURE...AND THIS COULD LEAD TO CHANCE OF
PRECIPITATION SUNDAY NIGHT. MONDAY BECOMES MORE MURKY AS THE ECMWF
SHOWS MUCH COLDER AIR SPILLING INTO THE FORECAST AREA. WOULD LIKE
TO SEE SOME CONFIRMATION BY THE GFS OR RUN TO RUN CONTINUITY BY THE
EURO MODEL. WILL NOT MAKE TOO MANY CHANGES FROM THE CONSENSUS
OUTPUT...BUT DID LOWER MAX TEMPS ACROSS THE NWRN COLORADO VALLEYS.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z WEDNESDAY AFTERNOON)
ISSUED AT 1021 AM MST TUE FEB 26 2013
THE UPPER LEVEL TROF CROSSING EASTERN UTAH AND WESTERN COLORADO
WILL CONTINUE TO BRING WIDESPREAD SNOWFALL TO AIRPORTS EAST OF A
2OW KCAG-KMTJ-PSO LINE DURING THE AFTERNOON AND EARLY
EVENING...WITH SCATTERED TO ISOLATED SHOWERS WEST OF THIS LINE.
MVFR TO IFR CONDITIONS CAN BE EXPECTED OVER THE KEGE AND KASE
TERMINALS THROUGH THE EVENING PERIOD AS WELL. KRIL...KGJT AND KMTJ
ARE RUNNING A VFR LEVELS BUT PASSING SHOWERS THIS AFTERNOON COULD
BRING TEMPORARY LOWERED FLIGHT CRITERIA THROUGH THIS TIME AS WELL.
MOUNTAIN OSBCURATIONS ARE ALSO LIKELY TO PERSIST THROUGH THE LATE
EVENING AND EARLY MORNING HOURS AS THIS WAVE SLOWLY MOVES ONTO THE
PLAINS AND BRINGS IN SOME DRIER AIR.
&&
.GJT WATCHES/WARNINGS/ADVISORIES...
CO...WINTER WEATHER ADVISORY UNTIL 9 PM MST THIS EVENING FOR COZ012-
017-018.
WINTER STORM WARNING UNTIL 9 AM MST WEDNESDAY FOR COZ009.
WINTER WEATHER ADVISORY UNTIL MIDNIGHT MST TONIGHT FOR COZ007-
008.
WINTER WEATHER ADVISORY UNTIL 9 AM MST WEDNESDAY FOR COZ004-010-
013.
WINTER WEATHER ADVISORY UNTIL 6 PM MST THIS EVENING FOR COZ011-
014.
UT...NONE.
&&
$$
UPDATE...JDC
SHORT TERM...EH
LONG TERM...PF
AVIATION...15
AREA FORECAST DISCUSSION
NWS COLUMBIA SC
210 PM EST TUE FEB 26 2013
.SYNOPSIS...
AN OCCLUDED FRONT WILL MOVE THROUGH THE FORECAST AREA LATE THIS
AFTERNOON. DRYING WILL OCCUR BEHIND THIS FRONT FOR TONIGHT. THE
ASSOCIATED STRONG LOW PRESSURE CENTER WILL BE NORTH OF THE
FORECAST AREA THROUGH THURSDAY AND RESULT IN BREEZY CONDITIONS IN
OUR AREA.
&&
.NEAR TERM /THROUGH TONIGHT/...
THE COOL AND STABLE AIR WAS WELL ENTRENCHED IN THE NORTH AND WEST
SECTIONS OF THE FORECAST AREA. THE WARM FRONT WAS CLOSE TO THE
SOUTHEAST PART. TEMPERATURES RANGED FROM NEAR 40 IN THE NORTH TO
AROUND 50 IN THE SOUTH. THE MAIN H85 WARM ADVECTION PATTERN AND
WIDESPREAD RAIN HAS SHIFTED NORTHEAST OF THE FORECAST AREA. THE
MAIN FORECAST PROBLEM IS HOW FAR NORTHWARD AND INLAND THE WARM
FRONT WILL MOVE. SOME BREAKS IN THE CLOUDINESS WERE OCCURRING NEAR
THE EXTREME SOUTHEAST PART INDICATING THE WARM FRONT MAY GET INTO
THAT AREA. SATELLITE TRENDS INDICATED THE MID- LEVEL DRY SLOT WILL
MOVE INTO THE AREA THIS AFTERNOON WITH ITS ASSOCIATED ENHANCED
INSTABILITY. STRONG SHEAR CONTINUES OVER THE AREA. THE KCAE 88D
SHOWED 2000 FOOT WINDS NEAR 35 KNOTS. THE SHEAR AND POSSIBLE
DEVELOPMENT OF SURFACE-BASED INSTABILITY SUPPORTS A POSSIBILITY OF
SEVERE THUNDERSTORMS MAINLY NEAR THE WARM FRONT IN THE SOUTHEAST
PART.
WEDGE WILL ERODE FROM SOUTH TO NORTH DURING THE EVENING AS SURFACE
LOW MOVES NORTHEAST OF THE REGION AND SOUTHWEST LOW LEVEL FLOW
DEVELOPS. EXPECT PARTLY CLOUDY SKIES TO DEVELOP...COULD BE LATE
IN THE NORTHERN MIDLANDS THOUGH. WINDS IN THE BOUNDARY LAYER WINDS 10 TO
20 KTS AND WITH MIXING SO EXPECT TEMPERATURES TO STAY UP DESPITE
DRY AIR ADVECTION. WITH WARMER LAKE TEMPERATURES GUSTY WINDS
PROBABLY WILL DEVELOP ON THE AREA LAKES OVERNIGHT SO WILL POST
LAKE WIND ADVISORY. MOS TEMPERATURES LOOK OK.
&&
.SHORT TERM /WEDNESDAY THROUGH THURSDAY NIGHT/...
AIR MASS DRYING OUT THROUGH THE PERIOD. WARM ADVECTION NOTED
WEDNESDAY EXPECT TEMPERATURES CLOSER TO NORMAL...IN THE LOW TO MID
60S. TIGHT SURFACE PRESSURE GRADIENT SO EXPECT GUSTY WINDS
ESPECIALLY IN THE AFTERNOON WILL CONTINUE LAKE WIND ADVISORY
THROUGH SUNSET. LAKE WIND MAY NEED TO BE EXTENDED INTO THURSDAY AS RE-
ENFORCING COLD FRONT MOVES THROUGH WEDNESDAY NIGHT. ALTHOUGH COLD
ADVECTION THURSDAY...OFFSETTING STRONG DOWNSLOPE FLOW EXPECTED BUT WILL
FORECAST TEMPERATURES COOLER THAN WEDNESDAY...SLIGHTLY BELOW MOS CONSENSUS.
&&
.LONG TERM /FRIDAY THROUGH MONDAY/...
SEVERAL SHORT WAVES MOVING THROUGH THE REGION IN BROAD UPPER
LEVEL CYCLONIC FLOW BUT MOISTURE SHOULD BE LIMITED. LATEST GFS AND
ECMWF SHOW AN UPPER LOW MOVING OVER THE AREA SATURDAY/SATURDAY
NIGHT WITH LIMITED MOISTURE TO WORK WITH. POP GUIDANCE NEAR
CLIMATOLOGY BUT NOTICEABLE SPIKE UP IN POPS. SOUNDING ANALYSIS
SUGGEST MOISTURE WILL BE QUITE SHALLOW ACROSS MOST OF THE
MIDLANDS. ICE CRYSTAL GROWTH NOT LIKELY...GFS SUGGESTS BETTER
CHANCE OF WINTER WEATHER NORTH. ECMWF IS DRIER. WILL MENTION
SLIGHT CHANCE SHOWERS OR SNOW SHOWERS MAINLY SATURDAY NIGHT AND
EARLY SUNDAY IN THE PIEDMONT AND NORTH MIDLANDS...OTHERWISE WILL
CONTINUE DRY FORECAST. TEMPERATURES BELOW NORMAL.
&&
.AVIATION /19Z TUESDAY THROUGH SUNDAY/...
THE COOL AND MOIST WEDGE PATTERN WAS IN PLACE EARLY THIS AFTERNOON
WITH WIDESPREAD IFR CONDITIONS. ABOVE THE WEDGE THE CAE 88D WAS
INDICATING 2000 FOOT WINDS AROUND 35 KNOTS. WE HAVE INCLUDED LLWS IN
THE TERMINAL FORECASTS. MIXING BEHIND THE OCCLUDED FRONT SHOULD
BRING IMPROVING CONDITIONS FROM SOUTHWEST TO NORTHEAST. SATELLITE
TRENDS SUPPORT THE IMPROVEMENT IN THE CENTRAL SAVANNAH RIVER AREA.
IMPROVEMENT MAY NOT OCCUR FARTHER NORTH UNTIL THE EVENING AS
INDICATED BY THE LATEST HRRR FLIGHT CATEGORY FORECAST AND GFS LAMP.
DRYING SHOULD EVENTUALLY BECOME DOMINATE ACROSS ALL OF THE AREA
TONIGHT. DESPITE LOW-LEVEL MOISTURE ASSOCIATED WITH THE RECENT RAIN
FOG APPEARS UNLIKELY DURING THE EARLY MORNING HOURS BECAUSE OF WIND
AND DRYING. THE PRESSURE GRADIENT ASSOCIATED WITH STRONG LOW PRESSURE
NORTH OF THE AREA WILL SUPPORT BREEZY CONDITIONS WEDNESDAY. MODEL
TIME-HEIGHT DISPLAYS AND EXPECTED MIXING SUPPORT GUSTS NEAR 24 KNOTS.
.EXTENDED AVIATION OUTLOOK...
STRONG LOW PRESSURE CENTERED NORTH OF THE AREA WILL BRING BREEZY
CONDITIONS DURING THE REST OF WEDNESDAY AND THURSDAY.
&&
.CAE WATCHES/WARNINGS/ADVISORIES...
SC...LAKE WIND ADVISORY FROM 6 PM THIS EVENING TO 7 PM EST
WEDNESDAY FOR SCZ015-016-018-020>022-025>028.
LAKE WIND ADVISORY UNTIL 7 PM EST WEDNESDAY FOR SCZ029>031-
035>038-041.
GA...LAKE WIND ADVISORY FROM 6 PM THIS EVENING TO 7 PM EST
WEDNESDAY FOR GAZ040-063-064.
LAKE WIND ADVISORY UNTIL 7 PM EST WEDNESDAY FOR GAZ065-077.
&&
$$
AREA FORECAST DISCUSSION
NWS DES MOINES IA
347 PM CST TUE FEB 26 2013
.SHORT TERM /TONIGHT/...
WINTER STORM WILL PERSIST THROUGH WEDNESDAY MORNING AS LIGHT TO
MODERATE SNOW BANDING CONTINUES ON THE BACKSIDE OF THE SURFACE LOW
LOCATED IN SOUTHEAST MISSOURI. SURFACE LOW LOOKS TO SLOWLY MIGRATE
NORTHEAST FROM SOUTHEAST MISSOURI INTO CENTRAL ILLINOIS THIS EVENING
INTO TOMORROW MORNING. LEANED TOWARD A SREF/GFS/NAM12 BLEND FOR
TRENDS TONIGHT.
WEAK LIFT WITHIN THE DENDRITIC GROWTH ZONE CONTINUES THIS AFTERNOON
AND TONIGHT...AND EVEN PERSISTS INTO WEDNESDAY MORNING. HIGHER
CONFIDENCE WITH THE ADDITIONAL LIGHT SNOW AMOUNTS THROUGH WEDNESDAY
MORNING RESULTING IN ROUGHLY 1 TO 4 INCHES OF ADDITIONAL SNOW
THROUGH 12Z ACROSS THE WARNING AREA. THE SNOW BAND AXIS LOOKS TO
CONTINUE TO SLOWLY PIVOT COUNTERCLOCKWISE AROUND THE CENTRAL PORTION
OF THE FORECAST RESULTING IN SOME AREAS RECEIVING AN ELONGATED
PERIOD OF MODERATE TO BRIEF HEAVY SNOW THIS EVENING. WITH THE
CURRENT TRACK OF THE SURFACE LOW...NOT EXPECTING THIS BAND TO DRIFT
SOUTHEAST ALL THAT MUCH UNTIL EARLY WEDNESDAY MORNING.
GENERALLY EXPECTING A HALF TO POSSIBLY ONE INCH PER HOUR SNOWFALL
RATES THIS EVENING WITH THE WEAK LIFT IN THE DENDRITIC LAYER. SREF
100MB/50MB DENDRITE GROWTH ZONE PARAMETER DEPICTING 80-90 PERCENT
PROBABILITY OF DENDRITIC SNOW THROUGH TOMORROW AND MATCHES UP WELL
WITH PREVIOUSLY MENTION BAND PIVOTING ACROSS CENTRAL IOWA. BUFR
SOUNDINGS REMAIN DEEPLY SATURATED THROUGH WEDNESDAY MORNING...WITH
THE RAP SHOWING A MID LEVEL DRY LAYER ADVECTING INTO DSM TO ALO AND
MAY SEE A BRIEF BREAK IN THE SNOW MID TO LATE EVENING.
WINDS ATOP THE MIXED LAYER RANGE FROM 25 TO 30KTS THIS AFTERNOON AND
TONIGHT AND EXPECTING BLOWING SNOW IMPACTS TO CONTINUE AS WELL.
LEANED TOWARDS THE GFS/SREF QPF AMOUNTS TONIGHT AS NAM SEEMS TO HIGH
ACROSS THE EAST...ESPECIALLY WITH THE WEAKER FORCING.
.LONG TERM /WEDNESDAY THROUGH TUESDAY/...
WEAKER LIFT WILL PERSIST INTO WEDNESDAY WITH THE SPC SREF INDICATING
DEEP DENDRITIC GROWTH LAYER CONTINUING THROUGH CENTRAL IOWA. ALL
SOUNDINGS CONTINUE TO ALSO SHOW DEEP SATURATION THROUGH AT LEAST
MIDDAY TOMORROW AND ANTICIPATE THE LIGHT SNOW TO CONTINUE. HAVE
GONE WITH LIKELY TO CATEGORICAL POPS FOR MUCH OF THE AREA UNDER THE
CURRENT HEADLINE WITH THE SHARP CUTOFF ON THE NORTHERN SIDE OF THE
PCPN AREA PERSISTING. WINDS WILL REMAIN RATHER STRONG THROUGH THE
DAY WITH BRISK NORTHWEST FLOW PERSISTING WITH DECENT PRESSURE
GRADIENT. EVENTUALLY...THE FORCING WILL BE DIMINISHING WITH THE
SNOW TAPERING TO FLURRIES BY LATER IN THE DAY. CLOUDINESS IS
EXPECTED TO PERSIST AS WELL IN CYCLONIC FLOW ON BACKSIDE INTO
WEDNESDAY NIGHT WITH AN APPROACHING SHORTWAVE ON THURSDAY AND
THURSDAY NIGHT HELPING THE CLOUDINESS TO MAINTAIN. IN FACT...SOME
WEAK LIFT WITH THIS PASSING WAVE ON FRIDAY MAY HELP TO PRODUCE SOME
FLURRIES IN SOUTHERN IOWA DURING THE DAY.
UPPER RIDGING WILL SLIDE THROUGH THE REGION INTO THE WEEKEND WITH
QUIET WEATHER DURING THIS TIME. TEMPERATURES WILL REMAIN BELOW
NORMAL WITH WIDESPREAD SNOW PACK AND ONLY WEAK ADVECTION UNTIL
SUNDAY NIGHT. THIS WARM ADVECTION IS IN ADVANCE OF THE NEXT SYSTEM
WHICH WILL PASS THROUGH THE REGION ON MONDAY INTO TUESDAY IN BROAD
NORTHWEST FLOW. BOTH GFS AND EURO HAVE INDICATED SOME DECENT
FORCING AND ANTICIPATE PCPN DEVELOPING AND SLIDING ACROSS THE STATE
ON MONDAY INTO EARLY TUESDAY. SOUNDINGS WOULD INDICATE GENERALLY
SNOW DURING THIS TIME ACROSS THE STATE WITH LIGHT TO MODERATE
ACCUMULATIONS EXPECTED.
&&
.AVIATION 26/18Z...
MODERATE TO HEAVY BAND WILL CONTINUE TO PRESS WEST THROUGH THE
AFTERNOON HOURS. BRIEF BREAK AT DSM WRT TO VIS...BEFORE SPREADING
BACK IN BY AROUND 21Z. EXPECTING THE HEAVIEST BAND TO SKIRT ACROSS
FOD THROUGH 22Z THIS AFTERNOON AND HAVE IFR VIS MENTIONED THROUGH
THEN. ALO WILL SEE PERIODIC SHIFTS FROM IFR TO MVFR THROUGH THE
AFTERNOON. LATEST MODEL RUNS KEEP LIGHT TO LOCALLY MODERATE SNOW
THROUGH MUCH OF THE EVENING INTO EARLY WEDNESDAY MORNING...MAINLY
EXPECTING MVFR CONDITIONS WITH SOME BRIEF IFR CONDITIONS DUE TO
VIS/CIGS OVERNIGHT.
&&
.DMX WATCHES/WARNINGS/ADVISORIES...
WINTER STORM WARNING UNTIL NOON CST WEDNESDAY FOR
ADAIR-ADAMS-APPANOOSE-BLACK HAWK-BOONE-CLARKE-DALLAS-DAVIS-
DECATUR-GRUNDY-HARDIN-JASPER-LUCAS-MADISON-MAHASKA-MARION-MARSHALL-
MONROE-POLK-POWESHIEK-RINGGOLD-STORY-TAMA-TAYLOR-UNION-WAPELLO-
WARREN-WAYNE.
WINTER WEATHER ADVISORY UNTIL NOON CST WEDNESDAY FOR
AUDUBON-BREMER-BUTLER-CASS-FRANKLIN-GREENE-GUTHRIE-HAMILTON.
&&
$$
SHORT TERM...PODRAZIK
LONG TERM...COGIL
AVIATION...PODRAZIK
AREA FORECAST DISCUSSION
NWS JACKSON KY
1232 PM EST TUE FEB 26 2013
.UPDATE...
ISSUED AT 1126 AM EST TUE FEB 26 2013
JUST A MINOR UPDATE WAS NECESSARY WITH THIS MORNINGS FORECAST.
SEVERAL AREAS OF CLEARING APPEARED EARLIER THIS MORNING IN THE
EXTENSIVE CLOUD SHIELD THAT HAS BEEN OVERSPREADING KENTUCKY SINCE
LATE LAST NIGHT. THE SKY COVER GRIDS WERE UPDATED TO TRACK THESE
AREAS OF CLEARING ACROSS THE FORECAST AREA AND INTO VIRGINIA AND WEST
VIRGINIA OVER THE NEXT SEVERAL HOURS. THE PRECIPITATION PROBABILITY
FORECAST WAS ALSO UPDATED TO REFLECT THE SCATTERED SHOWER ACTIVITY
THAT HAS PERSISTED THROUGHOUT THE MORNING. IT STILL APPEARS THAT MORE
NUMEROUS RAIN SHOWERS AND PERHAPS A THUNDERSTORM OR TWO WILL OCCUR
THROUGHOUT THE AFTERNOON...BEFORE THINGS TAPER OFF DURING THIS
EVENING. THE CORRESPONDING WEATHER TYPE AND QPF GRIDS WERE ALSO
REFORMULATED TO ACCOUNT FOR THE UPDATED PRECIPITATION PROBABILITY
FORECAST. ALSO REMOVED MORNING AND AFTERNOON WORDING FROM THE ZONE
FORECAST TEXT PRODUCT TO FRESHEN THINGS UP.
UPDATE ISSUED AT 652 AM EST TUE FEB 26 2013
DOWNSLOPING WINDS HAVE DEFINITELY TAKEN ITS TOLL ON THE RAIN AS IT
HAS PUSHED ACROSS THE AREA. MOST PLACES ARE GETTING LUCKY JUST TO
SQUEEZE OUT A HUNDREDTH OF AN INCH OF RAIN. THUS...HAVE DECIDED TO
TRIM POPS BACK...ESPECIALLY ACROSS THE SOUTH WHERE THINGS ARE ALREADY
STARTING TO DRY OUT. WITHIN THE NEXT FEW HOURS...ALL OF THE RAIN
SHOULD DEPART OFF TO THE NORTH...LEAVING BEHIND MAINLY DRY CONDITIONS
FOR THE BALANCE OF THE MORNING. HOWEVER...ANOTHER ROUND OF SHOWERS
STILL LOOKS ON TAP FOR THIS AFTERNOON...AS ANOTHER BAND OF SHOWERS
PUSHES EAST ACROSS THE AREA. THIS TIME THINGS MAY BE MORE CONVECTIVE
IN NATURE WITH THE THREAT OF STRONG WINDS AND SMALL HAIL STILL A
THREAT. LATEST HRRR DEFINITELY SUPPORTS SOME STRONG
SHOWERS/THUNDERSTORMS DEVELOPING BY EARLY AFTERNOON.
&&
.SHORT TERM...(TODAY THROUGH WEDNESDAY)
ISSUED AT 320 AM EST TUE FEB 26 2013
UPPER LEVEL LOW WILL CONTINUE TO PUSH INTO THE OHIO RIVER VALLEY
TODAY WITH AN OCCLUDING FRONTAL BOUNDARY CONTINUING TO LIFT NORTH
ACROSS THE AREA THIS MORNING. A BAND OF RAIN SHOWERS WILL PUSH NORTH
THROUGH THE EARLY MORNING HOURS. DOWNSLOPING SOUTHEAST WINDS WILL
CONTINUE TO TRY TO EAT AWAY AT THIS RAIN AS IT MOVES ACROSS THE AREA.
THIS WILL KEEP OVERALL RAINFALL AMOUNTS ON THE LIGHT SIDE...BUT WE
SHOULD SEE JUST ABOUT EVERYONE MEASURE BY 13Z. THIS BAND WILL QUICKLY
DEPART TO THE NORTH SHORTLY AFTER DAYBREAK...WITH ONLY SOME ISOLATED
TO SCATTERED SHOWERS LINGERING NEAR THE I-75 CORRIDOR. DOWNSLOPING
WINDS WILL LIKELY KEEP MOST OF THE ACTIVITY CLOSER TO CENTRAL
KENTUCKY. EVENTUALLY WINDS WILL VEER AROUND TO THE SOUTH OR SOUTHWEST
THIS AFTERNOON AS ANOTHER IMPULSE RIDES NORTHEAST ACROSS THE AREA.
THIS WILL TRIGGER ANOTHER ROUND OF SCATTERED TO NUMEROUS SHOWERS. IN
ADDITION...INSTABILITY REMAINS QUITE IMPRESSIVE...SO CANNOT RULE OUT
SOME ISOLATED THUNDERSTORMS WITH PERHAPS SOME SMALL HAIL. FINALLY A
THIRD WAVE WILL RIDE NORTHEAST ACROSS THE AREA THIS
EVENING...GENERATING SOME MORE SCATTERED SHOWERS. BY THIS
EVENING...INSTABILITY WILL DEPART TO THE NORTH...SO NO THUNDER
THROUGH THE EVENING HOURS. AS WINDS VEER TO THE SOUTHWEST
TONIGHT...LOWER CIGS MAY OVERSPREAD THE AREA...POSSIBLY LEADING TO
SOME PATCHY DRIZZLE LATE TONIGHT. HOWEVER...UNCERTAINTY EXISTS WITH
HOW MUCH LOW LEVEL MOISTURE WILL DEVELOP WHICH WOULD BE NEEDED TO
ACHIEVE ANY DRIZZLE. FINALLY...AS THE UPPER LEVEL LOW CONTINUES TO
ROTATE EASTWARD ACROSS THE OHIO RIVER VALLEY ON WEDNESDAY...THIS
SYSTEM WILL SEND A VIGOROUS SHORTWAVE SOUTHEAST ACROSS THE
AREA...GIVING WAY TO ANOTHER ROUND OF RAIN. COLDER AIR WILL ALSO
SETTLE SOUTHWARD AND AS WE WETBULB THROUGH THE EVENING...WE SHOULD
SEE SOME SNOW STARTING TO MIX IN AS WE HEAD INTO THE EVENING HOURS.
AS FOR THE WIND ADVISORY...GOING TO LEAVE THE COUNTIES NEAR THE
VIRGINIA BORDER IN THE ADVISORY. THE MESONET STATION AT DORTON IS HAS
GUSTED UP TO 38 MPH AND THIS SHOULD ONLY GO HIGHER AS THE SYSTEM
MOVES TOWARDS US TODAY.
.LONG TERM...(WEDNESDAY NIGHT THROUGH MONDAY)
ISSUED AT 350 AM EST TUE FEB 26 2013
THE MODELS ARE IN RELATIVELY GOOD AGREEMENT ALOFT THROUGH THE FIRST
PART OF THE EXTENDED...ESPECIALLY CONSIDERING THE AMPLIFIED NATURE OF
THE PATTERN. A DEEP AND LARGE CLOSED LOW WILL SLOWLY ROLL OUT OF THE
OHIO VALLEY ON THURSDAY WITH THE GFS RUNNING SLIGHTLY FASTER THAN THE
ECMWF. IN THE WAKE OF THIS...A STEADY STREAM OF UNCONSOLIDATED ENERGY
WILL SLIP THROUGH THE REGION INTO FRIDAY WHILE THE WESTERN EXTENT OF
IT STARTS TO CARVE OUT ANOTHER LOW OVER THE MID MISSISSIPPI VALLEY.
THIS LOW BECOMES BETTER ESTABLISHED ON SATURDAY OVER THE TENNESSEE
VALLEY...MOST IMPRESSIVE IN THE GFS AND WEAKER IN BOTH THE ECMWF AND
GEM. THE BASIC CONCEPT AND MAIN WEATHER DRIVERS ARE THE SAME FROM ALL
THE MODELS AS PLENTY OF ENERGY ROTATES THROUGH THE REGION DOWNSTREAM
OF A BURGEONING RIDGE THROUGH THE ROCKY MOUNTAIN STATES.
ACCORDINGLY...A BLENDED SOLUTION LOOKS REASONABLE THROUGH THE BULK
OF THE EXTENDED. THIS MID LEVEL LOW WILL GET SQUEEZED SOUTHEAST
THROUGH THE WEEKEND...BUT MANAGE TO MAINTAIN CYCLONIC FLOW OVER EAST
KENTUCKY UNTIL SUNDAY NIGHT WHEN IT WILL FINALLY MOVE OFF TO THE EAST
AS HEIGHTS RISE LOCALLY...IN RESPONSE TO A FLATTENING OF THE
FORMERLY ROBUST TROUGH TO THE WEST. A SMALL PORTION OF THIS RIDGE
THEN WILL SLIP THROUGH THE OHIO VALLEY ON MONDAY YIELDING THE HIGHEST
HEIGHTS OF THE LONG TERM PORTION OF THE FORECAST.
SENSIBLE WEATHER WILL FEATURE A CHILLY AND UNSETTLED TIME FRAME AT
LEAST INTO THE START OF THE WEEKEND. COLDER AIR WILL MOVE INTO THE
REGION ON NORTHWEST WINDS BEHIND THE DEEP SFC LOW SPINNING OFF TO
THE NORTHEAST EARLY IN THE PERIOD. THE LOW WILL MAINTAIN THE LOW
LEVEL MOISTURE OVER THE AREA WITH A COLD ENOUGH COLUMN OF AIR TO
SUPPORT SNOW FOR THE BULK OF THE TIME...THOUGH LIMITED DIURNAL RISES
WILL PROBABLY YIELD A MIX WITH RAIN EACH AFTERNOON. THE QPF WILL
ALSO BE RATHER LIMITED THROUGH THE FIRST PART OF THE WEEKEND ALSO
SERVING TO KEEP THE ACCUMULATIONS OF SNOW IN CHECK FOR MOST
LOCATIONS. WOULD ACTUALLY BE SURPRISED TO SEE MUCH IN THE WAY OF
ACCUMULATIONS DURING THE DAYTIME HOURS WITH A BETTER SHOT AT LIGHT
AMOUNTS STICKING EACH NIGHT. AMOUNTS WILL BE MAXIMIZED ON THE RIDGES
OF SOUTHEAST KENTUCKY WITH SOME OF THE PEAKS NEAR VIRGINIA LIKELY TO
HAVE MULTIPLE INCHES ON THE GROUND BY SUNDAY MORNING. THE REST OF THE
AREA WILL LIKELY SKATE BY WITH AN INCH OR LESS AND MAINLY JUST
SKIFFS OF VARYING THICKNESS. AS A RESULT...DO NOT FORESEE MUCH OF AN
IMPACT ON THE ROADS FOR THIS TIME PERIOD DESPITE THE CHILL AND
FREQUENT TIMES OF SNOW. THAT SAID...A FEW HEAVIER SNOW BURSTS OR
BANDS WILL BE POSSIBLY AND THAT COULD CAUSE BRIEF TRAVEL CHALLENGES
THROUGHOUT THE END OF THE WEEK AND INTO THE WEEKEND. DRIER AIR SHOULD
MOVE INTO THE REGION FROM THE NORTHWEST ON SUNDAY AND PUT AN END TO
MOST OF THE PCPN THREAT...BUT MAINTAIN THE BELOW NORMAL AIR MASS IN
PLACE. HIGH PRESSURE AND SOME SUNSHINE SHOULD RESULT IN DRY
CONDITIONS ALLOWING TEMPERATURES TO CREEP BACK UP CLOSER TO NORMAL
FOR MONDAY.
THE CR GRID LOAD CAME IN PRETTY GOOD GIVEN THE CONSENSUS PREFERENCE.
MADE ONLY MINOR CHANGES...MAINLY TO BEEF UP POPS IN THE SOUTHEAST
TERRAIN AND LIMIT THEM TO THE WEST. DID ALSO ADD SOME TERRAIN
DETAIL INTO THE LOWS BOTH SATURDAY AND SUNDAY NIGHTS.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z WEDNESDAY AFTERNOON)
ISSUED AT 1230 PM EST TUE FEB 26 2013
DOWNSLOPING WINDS WILL CONTINUE THROUGH THE AFTERNOON...KEEPING
CEILINGS SOLIDLY VFR THROUGH THE AFTERNOON AND PERHAPS EVEN THROUGH A
GOOD CHUNK OF THE EVENING AT JKL AND LOZ...AT LEAST BASED ON CURRENT
OBSERVATIONS. SME WAS EXPERIENCING MVFR CIGS JUST BELOW 3K AS OF TAF
ISSUANCE...AND BASED ON UPSTREAM OBS...THIS TREND WILL CONTINUE THERE
FOR THE REMAINDER OF THE TAF PERIOD. THERE IS STILL AN OUTSIDE CHANCE
OF A THUNDERSTORM OR TWO POPPING UP IN EASTERN KENTUCKY THIS
AFTERNOON...BUT CONFIDENCE IS LOW THAT THIS WILL ACTUALLY OCCUR.
INSPITE OF THE LOW CONFIDENCE...VCTS GROUPS WERE USED IN ALL THREE
TAFS IN CASE A STRAY STORM IS ABLE TO FIRE UP THIS AFTERNOON NEAR ONE
OF THE TAF SITES. AS WINDS VEER AROUND TO THE SOUTHWEST LATE
TODAY...SOME LOWER CIGS MAY FINALLY MAKE THEIR WAY ACROSS THE
AREA...BUT SHOULD REMAIN MVFR WITH CIGS BETWEEN 2.5 AND 3K. STRONG
GUSTY WINDS WILL CONTINUE TODAY BEFORE SUBSIDING A BIT TONIGHT. AS
CEILINGS LOWER OVERNIGHT...SOME DRIZZLE AND ISOLATED LIGHT RAIN
SHOWERS WILL BE POSSIBLE.
&&
.JKL WATCHES/WARNINGS/ADVISORIES...
WIND ADVISORY UNTIL 4 PM EST THIS AFTERNOON FOR KYZ087-088-118-
120.
&&
$$
UPDATE...AR
SHORT TERM...KAS
LONG TERM...GREIF
AVIATION...AR
AREA FORECAST DISCUSSION
NWS JACKSON KY
1127 AM EST TUE FEB 26 2013
.UPDATE...
ISSUED AT 1126 AM EST TUE FEB 26 2013
JUST A MINOR UPDATE WAS NECESSARY WITH THIS MORNINGS FORECAST.
SEVERAL AREAS OF CLEARING APPEARED EARLIER THIS MORNING IN THE
EXTENSIVE CLOUD SHIELD THAT HAS BEEN OVERSPREADING KENTUCKY SINCE
LATE LAST NIGHT. THE SKY COVER GRIDS WERE UPDATED TO TRACK THESE
AREAS OF CLEARING ACROSS THE FORECAST AREA AND INTO VIRGINIA AND WEST
VIRGINIA OVER THE NEXT SEVERAL HOURS. THE PRECIPITATION PROBABILITY
FORECAST WAS ALSO UPDATED TO REFLECT THE SCATTERED SHOWER ACTIVITY
THAT HAS PERSISTED THROUGHOUT THE MORNING. IT STILL APPEARS THAT MORE
NUMEROUS RAIN SHOWERS AND PERHAPS A THUNDERSTORM OR TWO WILL OCCUR
THROUGHOUT THE AFTERNOON...BEFORE THINGS TAPER OFF DURING THIS
EVENING. THE CORRESPONDING WEATHER TYPE AND QPF GRIDS WERE ALSO
REFORMULATED TO ACCOUNT FOR THE UPDATED PRECIPITATION PROBABILITY
FORECAST. ALSO REMOVED MORNING AND AFTERNOON WORDING FROM THE ZONE
FORECAST TEXT PRODUCT TO FRESHEN THINGS UP.
UPDATE ISSUED AT 652 AM EST TUE FEB 26 2013
DOWNSLOPING WINDS HAVE DEFINITELY TAKEN ITS TOLL ON THE RAIN AS IT
HAS PUSHED ACROSS THE AREA. MOST PLACES ARE GETTING LUCKY JUST TO
SQUEEZE OUT A HUNDREDTH OF AN INCH OF RAIN. THUS...HAVE DECIDED TO
TRIM POPS BACK...ESPECIALLY ACROSS THE SOUTH WHERE THINGS ARE ALREADY
STARTING TO DRY OUT. WITHIN THE NEXT FEW HOURS...ALL OF THE RAIN
SHOULD DEPART OFF TO THE NORTH...LEAVING BEHIND MAINLY DRY CONDITIONS
FOR THE BALANCE OF THE MORNING. HOWEVER...ANOTHER ROUND OF SHOWERS
STILL LOOKS ON TAP FOR THIS AFTERNOON...AS ANOTHER BAND OF SHOWERS
PUSHES EAST ACROSS THE AREA. THIS TIME THINGS MAY BE MORE CONVECTIVE
IN NATURE WITH THE THREAT OF STRONG WINDS AND SMALL HAIL STILL A
THREAT. LATEST HRRR DEFINITELY SUPPORTS SOME STRONG
SHOWERS/THUNDERSTORMS DEVELOPING BY EARLY AFTERNOON.
&&
.SHORT TERM...(TODAY THROUGH WEDNESDAY)
ISSUED AT 320 AM EST TUE FEB 26 2013
UPPER LEVEL LOW WILL CONTINUE TO PUSH INTO THE OHIO RIVER VALLEY
TODAY WITH AN OCCLUDING FRONTAL BOUNDARY CONTINUING TO LIFT NORTH
ACROSS THE AREA THIS MORNING. A BAND OF RAIN SHOWERS WILL PUSH NORTH
THROUGH THE EARLY MORNING HOURS. DOWNSLOPING SOUTHEAST WINDS WILL
CONTINUE TO TRY TO EAT AWAY AT THIS RAIN AS IT MOVES ACROSS THE AREA.
THIS WILL KEEP OVERALL RAINFALL AMOUNTS ON THE LIGHT SIDE...BUT WE
SHOULD SEE JUST ABOUT EVERYONE MEASURE BY 13Z. THIS BAND WILL QUICKLY
DEPART TO THE NORTH SHORTLY AFTER DAYBREAK...WITH ONLY SOME ISOLATED
TO SCATTERED SHOWERS LINGERING NEAR THE I-75 CORRIDOR. DOWNSLOPING
WINDS WILL LIKELY KEEP MOST OF THE ACTIVITY CLOSER TO CENTRAL
KENTUCKY. EVENTUALLY WINDS WILL VEER AROUND TO THE SOUTH OR SOUTHWEST
THIS AFTERNOON AS ANOTHER IMPULSE RIDES NORTHEAST ACROSS THE AREA.
THIS WILL TRIGGER ANOTHER ROUND OF SCATTERED TO NUMEROUS SHOWERS. IN
ADDITION...INSTABILITY REMAINS QUITE IMPRESSIVE...SO CANNOT RULE OUT
SOME ISOLATED THUNDERSTORMS WITH PERHAPS SOME SMALL HAIL. FINALLY A
THIRD WAVE WILL RIDE NORTHEAST ACROSS THE AREA THIS
EVENING...GENERATING SOME MORE SCATTERED SHOWERS. BY THIS
EVENING...INSTABILITY WILL DEPART TO THE NORTH...SO NO THUNDER
THROUGH THE EVENING HOURS. AS WINDS VEER TO THE SOUTHWEST
TONIGHT...LOWER CIGS MAY OVERSPREAD THE AREA...POSSIBLY LEADING TO
SOME PATCHY DRIZZLE LATE TONIGHT. HOWEVER...UNCERTAINTY EXISTS WITH
HOW MUCH LOW LEVEL MOISTURE WILL DEVELOP WHICH WOULD BE NEEDED TO
ACHIEVE ANY DRIZZLE. FINALLY...AS THE UPPER LEVEL LOW CONTINUES TO
ROTATE EASTWARD ACROSS THE OHIO RIVER VALLEY ON WEDNESDAY...THIS
SYSTEM WILL SEND A VIGOROUS SHORTWAVE SOUTHEAST ACROSS THE
AREA...GIVING WAY TO ANOTHER ROUND OF RAIN. COLDER AIR WILL ALSO
SETTLE SOUTHWARD AND AS WE WETBULB THROUGH THE EVENING...WE SHOULD
SEE SOME SNOW STARTING TO MIX IN AS WE HEAD INTO THE EVENING HOURS.
AS FOR THE WIND ADVISORY...GOING TO LEAVE THE COUNTIES NEAR THE
VIRGINIA BORDER IN THE ADVISORY. THE MESONET STATION AT DORTON IS HAS
GUSTED UP TO 38 MPH AND THIS SHOULD ONLY GO HIGHER AS THE SYSTEM
MOVES TOWARDS US TODAY.
.LONG TERM...(WEDNESDAY NIGHT THROUGH MONDAY)
ISSUED AT 350 AM EST TUE FEB 26 2013
THE MODELS ARE IN RELATIVELY GOOD AGREEMENT ALOFT THROUGH THE FIRST
PART OF THE EXTENDED...ESPECIALLY CONSIDERING THE AMPLIFIED NATURE OF
THE PATTERN. A DEEP AND LARGE CLOSED LOW WILL SLOWLY ROLL OUT OF THE
OHIO VALLEY ON THURSDAY WITH THE GFS RUNNING SLIGHTLY FASTER THAN THE
ECMWF. IN THE WAKE OF THIS...A STEADY STREAM OF UNCONSOLIDATED ENERGY
WILL SLIP THROUGH THE REGION INTO FRIDAY WHILE THE WESTERN EXTENT OF
IT STARTS TO CARVE OUT ANOTHER LOW OVER THE MID MISSISSIPPI VALLEY.
THIS LOW BECOMES BETTER ESTABLISHED ON SATURDAY OVER THE TENNESSEE
VALLEY...MOST IMPRESSIVE IN THE GFS AND WEAKER IN BOTH THE ECMWF AND
GEM. THE BASIC CONCEPT AND MAIN WEATHER DRIVERS ARE THE SAME FROM ALL
THE MODELS AS PLENTY OF ENERGY ROTATES THROUGH THE REGION DOWNSTREAM
OF A BURGEONING RIDGE THROUGH THE ROCKY MOUNTAIN STATES.
ACCORDINGLY...A BLENDED SOLUTION LOOKS REASONABLE THROUGH THE BULK
OF THE EXTENDED. THIS MID LEVEL LOW WILL GET SQUEEZED SOUTHEAST
THROUGH THE WEEKEND...BUT MANAGE TO MAINTAIN CYCLONIC FLOW OVER EAST
KENTUCKY UNTIL SUNDAY NIGHT WHEN IT WILL FINALLY MOVE OFF TO THE EAST
AS HEIGHTS RISE LOCALLY...IN RESPONSE TO A FLATTENING OF THE
FORMERLY ROBUST TROUGH TO THE WEST. A SMALL PORTION OF THIS RIDGE
THEN WILL SLIP THROUGH THE OHIO VALLEY ON MONDAY YIELDING THE HIGHEST
HEIGHTS OF THE LONG TERM PORTION OF THE FORECAST.
SENSIBLE WEATHER WILL FEATURE A CHILLY AND UNSETTLED TIME FRAME AT
LEAST INTO THE START OF THE WEEKEND. COLDER AIR WILL MOVE INTO THE
REGION ON NORTHWEST WINDS BEHIND THE DEEP SFC LOW SPINNING OFF TO
THE NORTHEAST EARLY IN THE PERIOD. THE LOW WILL MAINTAIN THE LOW
LEVEL MOISTURE OVER THE AREA WITH A COLD ENOUGH COLUMN OF AIR TO
SUPPORT SNOW FOR THE BULK OF THE TIME...THOUGH LIMITED DIURNAL RISES
WILL PROBABLY YIELD A MIX WITH RAIN EACH AFTERNOON. THE QPF WILL
ALSO BE RATHER LIMITED THROUGH THE FIRST PART OF THE WEEKEND ALSO
SERVING TO KEEP THE ACCUMULATIONS OF SNOW IN CHECK FOR MOST
LOCATIONS. WOULD ACTUALLY BE SURPRISED TO SEE MUCH IN THE WAY OF
ACCUMULATIONS DURING THE DAYTIME HOURS WITH A BETTER SHOT AT LIGHT
AMOUNTS STICKING EACH NIGHT. AMOUNTS WILL BE MAXIMIZED ON THE RIDGES
OF SOUTHEAST KENTUCKY WITH SOME OF THE PEAKS NEAR VIRGINIA LIKELY TO
HAVE MULTIPLE INCHES ON THE GROUND BY SUNDAY MORNING. THE REST OF THE
AREA WILL LIKELY SKATE BY WITH AN INCH OR LESS AND MAINLY JUST
SKIFFS OF VARYING THICKNESS. AS A RESULT...DO NOT FORESEE MUCH OF AN
IMPACT ON THE ROADS FOR THIS TIME PERIOD DESPITE THE CHILL AND
FREQUENT TIMES OF SNOW. THAT SAID...A FEW HEAVIER SNOW BURSTS OR
BANDS WILL BE POSSIBLY AND THAT COULD CAUSE BRIEF TRAVEL CHALLENGES
THROUGHOUT THE END OF THE WEEK AND INTO THE WEEKEND. DRIER AIR SHOULD
MOVE INTO THE REGION FROM THE NORTHWEST ON SUNDAY AND PUT AN END TO
MOST OF THE PCPN THREAT...BUT MAINTAIN THE BELOW NORMAL AIR MASS IN
PLACE. HIGH PRESSURE AND SOME SUNSHINE SHOULD RESULT IN DRY
CONDITIONS ALLOWING TEMPERATURES TO CREEP BACK UP CLOSER TO NORMAL
FOR MONDAY.
THE CR GRID LOAD CAME IN PRETTY GOOD GIVEN THE CONSENSUS PREFERENCE.
MADE ONLY MINOR CHANGES...MAINLY TO BEEF UP POPS IN THE SOUTHEAST
TERRAIN AND LIMIT THEM TO THE WEST. DID ALSO ADD SOME TERRAIN
DETAIL INTO THE LOWS BOTH SATURDAY AND SUNDAY NIGHTS.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z WEDNESDAY MORNING)
ISSUED AT 652 AM EST TUE FEB 26 2013
DOWNSLOPING WINDS WILL CONTINUE INTO THE AFTERNOON...KEEPING CEILINGS
SOLIDLY VFR THROUGH THE AFTERNOON AND PERHAPS EVEN THROUGH A GOOD
CHUNK OF THE EVENING. AS WINDS VEER AROUND TO THE SOUTHWEST LATE
TODAY...SOME LOWER CIGS MAY FINALLY WORK THEIR WAY ACROSS THE
AREA...BUT SHOULD REMAIN MVFR. STRONG GUSTY WINDS WILL CONTINUE TODAY
BEFORE SUBSIDING A BIT TONIGHT. AS CEILINGS LOWER TONIGHT...SOME
DRIZZLE MAY BE POSSIBLE.
&&
.JKL WATCHES/WARNINGS/ADVISORIES...
WIND ADVISORY UNTIL 4 PM EST THIS AFTERNOON FOR KYZ087-088-118-
120.
&&
$$
UPDATE...AR
SHORT TERM...KAS
LONG TERM...GREIF
AVIATION...KAS
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
429 PM EST TUE FEB 26 2013
.SHORT TERM...(THIS EVENING THROUGH WEDNESDAY)
ISSUED AT 428 PM EST TUE FEB 26 2013
WATER VAPOR IMAGERY AND RUC ANALYSIS SHOW PRONOUNCED SPLIT FLOW
CONTINUING ACROSS NAMERICA. IN WHAT HAS BEEN A VERY ACTIVE SRN
STREAM RECENTLY...A WELL-DEFINED MID LEVEL LOW IS MOVING ENE INTO
THE LWR OHIO VALLEY. SRN STREAM RIDGING AHEAD OF FEATURE EXTENDS
FROM JUST OFF THE SE COAST TO SRN NEW ENGLAND AND THEN BACK INTO THE
UPPER LAKES. WITH NRN STREAM WELL N OF HERE...ARCTIC AIR HAS
RETREATED INTO NRN CANADA. CLOSER TO HOME...PESKY STRATOCU HAS
CONTINUED TO PLAGUE UPPER MI TODAY. HOWEVER...ROUGHLY THE W THIRD OF
THE FCST AREA HAS ENJOYED MOSTLY SUNNY SKIES FOR AT LEAST A PORTION
OF THE DAY. THE POCKET OF MOSTLY SUNNY SKIES CURRENTLY OVER THE W IS
SHOWING SIGNS OF EXPANDING EASTWARD AS STRONGER DAYTIME HEATING
UNDER HIGHER LATE FEB SUN ANGLE IS WORKING ON LOWER ALBEDO FORESTED
TERRAIN TO RAISE MIXED LAYER AND THUS MIX OUT THE SHALLOW MOIST
LAYER.
DURING THE SHORT TERM...MAIN FCST ISSUE WILL REVOLVE AROUND
NORTHWARD PROGESS OF A WEAKENING PCPN SHIELD SPREADING N AROUND SRN
STREAM MID LEVEL LOW AS IT TRACKS INTO THE UPPER OHIO VALLEY/LWR
LAKES REGION. EARLY ON...LOW CLOUDS WILL CONTINUE TO PRESENT SOME
ISSUES. CLEARING MAY CONTINUE TO EXPAND E FROM WRN UPPER MI OVER THE
NEXT COUPLE OF HRS...BUT WITH LOSS OF DAYTIME HEATING...STRATOCU
WILL PROBABLY TEND TO SPREAD BACK INTO THE AREAS THAT HAVE
CLEARED...ESPECIALLY IF THE STRATOCU TO THE E AND NE DOES NOT BREAK
UP DURING THE LATE AFTN/EVENING. LATEST VIS SATELLITE IMAGERY DOES
SHOW STRATOCU THINNING OVER ERN LAKE SUPERIOR...SO THERE MAY YET BE
SOME MORE CLEARING DURING THE EVENING. WILL BE A TREND TO MONITOR.
WHILE CLOUDS WILL AGAIN MAKE OR BREAK TEMP FCST...THERE WILL LIKELY
NOT BE AS GREAT OF A TEMP SPREAD TONIGHT AS IN PREVIOUS NIGHTS BTWN
AREAS WITH CLOUDS AND AREAS WITH LESS CLOUD SINCE INCREASING
GRADIENT WINDS WILL LIMIT RADIATIONAL COOLING. TRENDED TEMPS TOWARD
RAW MODEL GUIDANCE WHICH PUTS MIN TEMPS GENERALLY IN THE MID/UPPER
20S.
AS FOR PCPN...THE STRONG ISENTROPIC ASCENT COMPONENT TO PCPN SHIELD
SPREADING N INTO SRN WI/SRN MI ATTM WILL GRADUALLY FADE WITH TIME AS
THE ZONE OF STRONG ASCENT TRANSLATES EASTWARD...RESULTING IN ZONE OF
HEAVIEST PCPN SHIFTING E TOWARD THE LWR LAKES/SRN NEW ENGLAND
TONIGHT/WED MORNING. THUS...A DECAYING SHIELD OF PCPN WILL BE
LIFTING TOWARD UPPER MI TONIGHT/WED MORNING. RECENT MODEL TRENDS
GENERALLY POINT TOWARD A MORE AGGRESSIVE PUSH OF LIGHT SNOW INTO
UPPER MI. GIVEN THE STRONG NORTHWARD PUSH OF PCPN THRU LWR MI ATTM
AND THE LACK OF A LAYER OF VERY DRY AIR AT THE LOWER LEVELS TO THE N
ACROSS UPPER MI...HAVE OPTED TO TREND PCPN CHC SLIGHTLY FARTHER N
THAN PREVIOUS FCST TO ROUGHLY A KERY/KSAW/KIMT LINE AND RAISED POPS
TO HIGH CHC ALONG LAKE MI. WITH 850MB TEMPS NO LWR THAN -8/-9C...
IT`S VERY UNLIKELY THAT ANY LES WILL DEVELOP OFF LAKE SUPERIOR UNDER
STRONG NE CYCLONIC FLOW WED. IF SHIELD OF LIGHT SYNOPTIC SNOW DOES
REACH LAKE SUPERIOR...THEN A LITTLE LAKE COMPONENT WILL BE THERE.
.LONG TERM...(WEDNESDAY NIGHT THROUGH TUESDAY)
ISSUED AT 428 PM EST TUE FEB 26 2013
LITTLE CHANGES TO THE LONG TERM FROM 24 HOURS AGO...WITH THE
MAIN ITEM OF DIFFERENCE A SLIGHT WOBBLE TO THE NORTHWEST WITH THE
SYSTEM CURRENTLY MOVING THROUGH THE MID MISSISSIPPI VALLEY THAT
WILL MOVE THROUGH THE LOWER GREAT LAKES. THIS SLIGHT
ADJUSTMENT...PUSHES THE PRECIPITATION A TOUCH FARTHER INLAND FROM
LAKE MICHIGAN. BUT AS THE LONG TERM PERIOD BEGINS...THE LOW WILL
START IT/S EASTWARD SHIFT TOWARDS NEW YORK AND DIMINISH THE SNOW
ALONG THE LAKE MICHIGAN SHORELINE.
ATTENTION THEN TURNS TO THE AMOUNT OF MOISTURE AND COLD AIR IN THE
LOWER LEVELS TO SUPPORT LAKE ENHANCED AND UPSLOPE SNOW SHOWERS.
LATEST TRENDS IN THE MOISTURE AND COLD AIR /850MB TEMPERATURES
FALLING FROM -9C AT WEDNESDAY NIGHT TO -13C BETWEEN 900-850MB BY
THURSDAY AFTERNOON/ LEADS TO GREATER CONFIDENCE IN SCATTERED SNOW
SHOWERS OCCURRING FOR LOCATIONS NEAR LAKE SUPERIOR FROM PICTURED
ROCKS AND WESTWARD. INVERSION HEIGHTS AROUND 3-4KFT SHOULD KEEP THE
INTENSITY IN CHECK AND HELPS KEEP LAKE INDUCED CAPES BELOW 200
J/KG. THUS...WILL BUMP POPS UP 5-10 PERCENT INTO HIGHER END CHANCE
CATEGORY. SNOWFALL AMOUNTS SHOULD BE FAIRLY LIGHT...SINCE CLOUD
DEPTH IS FAIRLY LIMITED. WITH THE INITIAL CLOUD LAYER MAINLY BEING
BELOW THE DGZ WEDNESDAY NIGHT...WOULD EXPECT FLAKES TO BE FAIRLY
SMALL. BUT AS THE COLDER AIR ARRIVES...IT DOES ATTEMPT TO PUSH THE
CLOUD LAYER INTO THE DGZ AND HELP SNOW RATIOS. BUT WITH THE LIMITED
CLOUD DEPTH/MOISTURE TO WORK WITH...WOULDN/T EXPECT MUCH MORE THAN
AN INCH OR TWO OF TOTAL ACCUMULATION BY THE TIME IT STARTS WINDING
DOWN ON FRIDAY. THE HIGHEST AMOUNTS WILL BE IN THE FAVORED UPSLOPE
LOCATIONS WITH NORTHEAST WINDS...ESPECIALLY IN/NEAR THE HURON
MOUNTAINS WHICH COULD APPROACH 3 INCHES.
A BUILDING CANADIAN HIGH OVER HUDSON BAY WILL SLIDE A RIDGE SOUTH
INTO THE UPPER GREAT LAKES REGION FRIDAY AND IT WILL REMAIN INTO THE
FIRST PART OF THE NEXT WEEK. THIS WILL WORK TO REDUCE THE INVERSION
HEIGHTS TO 2KFT AND SHOULD BRING AN END TO THE LAKE ENHANCED/EFFECT
BY FRIDAY NIGHT. WILL GO WITH PARTLY CLOUDY SKIES THROUGH THE
WEEKEND...BUT THERE IS SOME CONCERN THAT THERE COULD BE LINGERING
LOW CLOUDS BELOW THE STRENGTHENING INVERSION DURING THAT TIME.
MAIN QUESTION FOR NEXT WEEK WILL BE THE LOCATION OF A SHORTWAVE
CUTTING THROUGH THE UPPER RIDGE OVER THE WESTERN CONUS AND IT/S
INFLUENCE ON THE UPPER TROUGH ON THE EAST COAST. 00Z ECMWF HOLDS
THE TROUGH OVER THE AREA...WHILE THE GFS TRIES TO PUSH THE RIDGE
OVER THE AREA ON MONDAY. THIS HAS THE POTENTIAL FOR WEAKENING THE
SURFACE RIDGE AND PUSHING SOME PRECIPITATION INTO THE AREA ON THE
EAST SIDE OF A LOW MOVING THROUGH CENTRAL PLAINS OR UPPER
MISSISSIPPI VALLEY. WILL RESPECT THE CONSISTENCY SHOWN IN THE ECMWF
OVER THE LAST SEVERAL DAYS AND TRY TO KEEP MUCH OF THE AREA DRY.
HIGH TEMPERATURES ARE STILL LOOKING TO BE BELOW NORMAL THROUGH THE
LONG TERM PERIOD. LOOKING AT THE LONGER RANGE FORECASTS /EVEN THOUGH
SKILL IS FAIRLY LIMITED/...NOT TOO MANY SIGNS OF SPRING FOR THE
FIRST WEEK OR TWO OF MARCH. GFS/ECMWF ENS MEANS ARE SHOWING 850MB
TEMPS BELOW NORMAL THROUGH THE FIRST WEEK AND GFS ENS 500MB MEAN
HEIGHTS ARE SHOWING A TROUGH REMAINING OVER THE EASTERN CONUS
THROUGH THE MIDDLE OF MARCH. AFTER BEING SPOILED BY WARM
MARCH WEATHER IN 2010/2012...ITS LOOKING LIKE MARCH WILL
BE MORE TRADITIONAL TEMPERATURE WISE. UNFORTUNATELY FOR SOME OF THE
LOCATIONS OF CENTRAL UPPER MICHIGAN THAT HAVE SEEN PROLONGED
DRYNESS...THIS PATTERN WON/T BE SUPPORTIVE OF ANY SIGNIFICANT
PRECIPITATION AND MAINLY JUST LIGHT PRECIPITATION FROM CLIPPERS.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z WEDNESDAY AFTERNOON)
ISSUED AT 1240 PM EST TUE FEB 26 2013
AT KIWD...EXPECT VFR CONDITIONS THRU THE AFTN. HOWEVER...DAYTIME
HEATING HAS LEAD TO OCNL BKN CIGS DEVELOPING OVER WRN UPPER MI PER
SATELLITE IMAGERY. SO THERE MAY BE A FEW PERIODS OF MVFR CIGS THIS
AFTN AT KIWD. KCMX HAS A SIMILAR SETUP TO KIWD...BUT WILL KEY ON
LARGE AREA OF STRATOCU OVER ERN LAKE SUPERIOR WHICH IS MAKING STEADY
PROGRESS WESTWARD. SIMPLE EXTRAPOLATION SUGGESTS MVFR CIGS MAY REACH
KCMX AROUND 22Z. AT KSAW...EXPECT HIGH MVFR CIGS TO RISE SLIGHTLY TO
VFR DURING THE AFTN HRS. TONIGHT INTO WED MORNING...LOW PRES MOVING
TOWARD THE LOWER LAKES WILL CAUSE A CYCLONIC NE FLOW TO STRENGTHEN.
THIS SHOULD RESULT IN MVFR CIGS DEVELOPING WHERE THIS FLOW MOISTENED
BY LAKE SUPERIOR WILL UPSLOPE AT KIWD/KSAW.
&&
.MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 428 PM EST TUE FEB 26 2013
TIGHTENING PRES GRADIENT BTWN HIGH PRES TO THE N AND NW AND LOW PRES
TRACKING THRU THE LWR OHIO VALLEY TO LWR LAKES WILL RESULT IN
NORTHEASTERLY WINDS ACROSS LAKE SUPERIOR INCREASING TO 20-30KT
TONIGHT THRU WED. MIGHT SEE A FEW GALE FORCE GUSTS WED AFTN OVER THE
E HALF. EVEN THOUGH THE LOW CONTINUES TO MOVE E THU...THE HIGH
BUILDING TOWARD THE AREA FROM N WILL MAINTAIN A TIGHT PRES
GRADIENT...RESULTING IN CONTINUED 20-30KT WINDS WITH SOME GALE FORCE
GUSTS POSSIBLE OVER THE E HALF THRU THU MORNING. WINDS WILL THEN
VERY SLOWLY DIMINISH FROM W TO E FRI/SAT AS THE HIGH PRES MOVES
CLOSER...BUT IT WILL PROBABLY BE SAT BEFORE WINDS DROP BLO 20KT
ACROSS THE ENTIRE LAKE. THE PERIOD OF STRONG WINDS WED NIGHT THRU
FRI WILL ALSO BRING THE POTENTIAL FOR FREEZING SPRAY. LIGHT WINDS
UNDER 10KT ARE EXPECTED SUN AS SFC HIGH PRES RIDGE WILL EXTEND FROM
HUDSON BAY S ACROSS LAKE SUPERIOR.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...ROLFSON
LONG TERM...SRF
AVIATION...ROLFSON
MARINE...ROLFSON
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
1240 PM EST TUE FEB 26 2013
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 357 AM EST TUE FEB 26 2013
00Z RAOBS/LATEST WV IMAGERY AND RUC ANALYSIS SHOW SPLIT FLOW PATTERN
ACRS NAMERICA...WITH THE UPR GRT LKS UNDER A POLAR JET STREAM WELL S
OF ARCTIC BRANCH IN CENTRL CANADA THAT HAS CONFINED THE BITTERLY
COLD ARCTIC AIR TO FAR NRN CANADA. AN ACTIVE SUBTROPICAL BRANCH
DOMINATES THE S HALF OF THE CONUS...WITH A POTENT DISTURBANCE MOVING
INTO THE LOWER-MID MS RIVER VALLEY. A DISTURBANCE WITHIN THE POLAR
BRANCH IS MOVING ACRS UPR MI EARLY THIS MRNG...BUT LIMITED MSTR
DEPTH PER 00Z GRB/APX RAOBS AND GENERAL LARGER SCALE ACYC FLOW
RELATED TO RDG AXIS EXTENDING WWD FM HI CENTER IN SE CANADA HAS
RESTRICTED ANY IMPACT TO AN AREA OF SC. THE BACK EDGE OF THIS CLD
AREA IS JUST INLAND FM THE W SHORE OF UPR MI CLOSER TO INCOMING AREA
OF DRY AIR DEPICTED ON THE 00Z INL/MPX RAOBS AND WHICH IS UNDER
DNVA/LARGE SCALE QVECTOR DVGC BEHIND THE SHRTWV. SKIES OVER FAR NW
WI/WRN LK SUP AND THE MN ARROWHEAD OF MOCLR...WHICH HAS ALLOWED SOME
FOG TO FORM WITH LGT WINDS. HI CLDS ON THE NRN EDGE OF THE
SUBTROPICAL BRANCH DISTURBANCE TO THE S ARE SPREADING SLOWLY NWD
THRU WI.
MAIN FCST CONCERNS TODAY ARE CLD TRENDS/IMPACT ON TEMPS. FOCUS FOR
TNGT SHIFTS TO WHETHER ANY PCPN ASSOCIATED WITH SRN BRANCH
DISTURBANCE WL IMPACT THE SRN CWA.
TODAY...POLAR BRANCH UPR RDG/DNVA/LARGE SCALE QVECTOR DVGC WL
DOMINATE UPR MI TODAY. AS THE SUBTROPICAL BRANCH SFC LO MOVES INTO
THE LOWER OH RIVER VALLEY BY 00Z WED...THE PRES GRADIENT WL TIGHTEN
OVER UPR MI TO THE WSW OF HI CENTERED IN SE CANADA...WITH AN INCRSG
ENE FLOW. ALTHOUGH THE LARGER SCALE NEGATIVE DYNAMICS WOULD INDICATE
A SLOW BREAKUP OF THE SC DOMINATAING MUCH OF THE CWA NOW...THIS LO
CLD IS WIDESPREAD TO THE E OF UPR MI THIS MRNG...THE SOURCE AIRMASS
FOR THE DVLPG E WIND. ON THE OTHER HAND...THE DIFFLUENT NATURE OF
THE LLVL FLOW AS WELL AS STRONG SUBSIDENCE FCST AT H925 SHOULD TEND
TO BREAK UP THE LO CLD. RECENT TRENDS SHOWN ON STLT IMAGERY/SFC OBS
CONFIRM THIS EXPECTATION. DIURNAL HEATING WITH INCRSG LATE FEB SUN
ANGLE WL ALSO TEND TO DISSIPATE THE SC OVER THE LAKES AS H85 TEMPS
ARE FCST TO BE ABOUT -4C...A TYPICAL EARLY SPRING SCENARIO. IN THIS
SCENARIO...SOME DIURNAL CU/SC WOULD TEND TO FORM OVER THE INTERIOR
FOLLOWING INITIAL CLRG. THE COVERAGE OF THIS CLD SHOULD BE LIMITED
BY THE RATHER LO INVRN BASE SHOWN ON NAM/GFS FCST SDNGS. MAINTAINED
OVERALL FLAVOR OF GOING FCST SHOWING A TERND FOR DECREASING CLDS
INTO THIS AFTN...WITH A BIT MORE CLD COVER OVER THE INTERIOR...
ESPECIALLY IN USPLOPE AREAS. MIXING TO H875 ON FCST SDNGS YIELDS HI
TEMPS CLOSE TO 40...MOST LIKELY IN AREAS OVER THE W THAT SEE MORE
SUNSHINE AND DOWNSLOPE IN LLVL ENE FLOW AWAY FM THE COOLING
INFLUENCE OF THE LKS. GOING FCST NEEDS ONLY MINOR ADJUSTMENTS.
TNGT...SUBTROPICAL BRANCH LO IS PROGGED TO MOVE NE INTO OH BY 12Z
WED. THE BULK OF THE NUMERICAL GUIDANCE SHOWS LGT QPF ON THE NW
FLANK OF THIS LO PRES BRUSHING JUST THE SE COUNTIES WITH SOME LGT
PCPN TOWARD 12Z WED...CONSISTENT WITH THE PASSAGE OF THE DEEP LYR
QVECTOR THRU LWR MI. DESPITE CYC NATURE OF THE INCRSG LLVL NE
FLOW...H85 TEMPS NO LOWER THAN ABOUT -5C AS WELL AS FCST DRY H85-7
LYR INDICATE THERE WL BE NO LK EFFECT/ENHANCED PCPN EVEN IF MORE SC
DVLPS IN THE UPSLOPE AREAS. OPTED TO RETAIN GOING SCHC POPS ONLY
CLOSE TO LK MI/BAY OF GREEN BAY.
.LONG TERM...(WEDNESDAY THROUGH MONDAY)
ISSUED AT 357 AM EST TUE FEB 26 2013
NOT MUCH IN THE WAY OF PRECIPITATION EXPECTED THROUGH THIS LONG TERM
PERIOD...WITH MARCH LIKELY COMING IN LIKE A LAMB /AS NOTED ON THE
PREVIOUS DISCUSSION/.
BY WEDNESDAY THE 500MB LOW WILL BE THE CLOSEST IT WILL GET TO THE
CWA...TRACKING FROM OHIO TO NE PENNSYLVANIA...SQUEEZING THE RIDGE
NORTH INTO ONTARIO. EXPECT NE FLOW AT THE SFC AND ALOFT WEDNESDAY.
THE 25/12Z CONTINUES TO SHOW A SOUTHERLY TREND TO THE TRACK...WITH A
DOUBLE BARREL LOW SPLITTING THE APPALACHIANS MERGING ACROSS THE NEW
ENGLAND STATES WEDNESDAY NIGHT. A MEER 24 HOURS AGO THE NAM SOLUTION
WAS FOR THE SURFACE LOW TO SWING ACROSS CENTRAL LOWER MICHIGAN...NOW
IT LOOKS TO BE MORE IN LINE IF NOT SLIGHTLY SLOWER THAN THE
ECMWF/GFS ON WEDNESDAY.
STRONG HIGH PRESSURE STRETCHING ACROSS NORTH CENTRAL CANADA ON
TUESDAY WILL PUSH INTO HUDSON BAY AND MANITOBA/ONTARIO
WEDNESDAY/WEDNESDAY NIGHT...WITH THE RIDGE EDGING ACROSS LAKE
SUPERIOR THURSDAY NIGHT THROUGH AT LEAST SUNDAY MORNING. WE STILL
EXPECT SOME BREEZY CONDITIONS NEAR THE LAKE SUPERIOR SHORELINE
WEDNESDAY THROUGH THURSDAY /PUSHING ACROSS MUCH OF CENTRAL UPPER
MICHIGAN DURING THE DAY THURSDAY/. WINDS WILL SLOWLY DIMINISH AS THE
LOW CONTINUES TO EXIT EAST AND THE SURFACE HIGH PUSHES OVERHEAD.
AS FOR THE CHANCE OF PRECIPITATION THROUGH THE PERIOD...IT IS PRETTY
MINIMAL. THE SYNOPTIC SNOW WILL ONLY CLIP AREAS NEAR LAKE MICHIGAN
WEDNESDAY INTO WEDNESDAY EVENING. EVEN WITH THE FAVORABLE UPSLOPE
WINDS OFF LAKE SUPERIOR...TEMPERATURES AT AND ABOVE THE SURFACE WILL
BE MARGINAL TO SUPPORT ANY ACCUMULATING SNOW SHOWERS.
COLDER AIR WILL FINALLY COME IN FOR THE END OF THE WORK WEEK...WITH
850MB TEMPERATURES FALLING TO AROUND -11C FRIDAY AFTERNOON...AND -12
TO -14C FRIDAY NIGHT THROUGH AT LEAST SUNDAY /WITH N-NE WINDS
CONTINUING THROUGH SATURDAY/.
THE 25/12Z ECMWF KEEPS THE RIDGE IN PLACE THROUGH TUESDAY...BECOMING
OUT OF PHASE WITH THE 25/18Z GFS BY MONDAY NIGHT /STRONG 1044MB HIGH
OVER NORTHERN MANITOBA AND ONTARIO...COMPARED TO THE 1005MB LOW
ACROSS ONTARIO/. WHILE THE 26/00Z GFS DID COME IT SLIGHTLY BETTER
AGREEMENT...IT JUST CAN NOT BEAT THE RUN TO RUN CONSISTENCY BEING
SHOWN BY THE ECMWF. CUT BACK THE SLIGHT CHANCE POPS GIVEN WITH A
CONSENSUS OF THE MODELS FOR DAY 6/MONDAY TO RIGHT ALONG THE
WISCONSIN BORDER...MINIMIZING THE INFLUENCE OF THE 26/00Z GFS RUN ON
THE POPS.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z WEDNESDAY AFTERNOON)
ISSUED AT 1240 PM EST TUE FEB 26 2013
AT KIWD...EXPECT VFR CONDITIONS THRU THE AFTN. HOWEVER...DAYTIME
HEATING HAS LEAD TO OCNL BKN CIGS DEVELOPING OVER WRN UPPER MI PER
SATELLITE IMAGERY. SO THERE MAY BE A FEW PERIODS OF MVFR CIGS THIS
AFTN AT KIWD. KCMX HAS A SIMILAR SETUP TO KIWD...BUT WILL KEY ON
LARGE AREA OF STRATOCU OVER ERN LAKE SUPERIOR WHICH IS MAKING STEADY
PROGRESS WESTWARD. SIMPLE EXTRAPOLATION SUGGESTS MVFR CIGS MAY REACH
KCMX AROUND 22Z. AT KSAW...EXPECT HIGH MVFR CIGS TO RISE SLIGHTLY TO
VFR DURING THE AFTN HRS. TONIGHT INTO WED MORNING...LOW PRES MOVING
TOWARD THE LOWER LAKES WILL CAUSE A CYCLONIC NE FLOW TO STRENGTHEN.
THIS SHOULD RESULT IN MVFR CIGS DEVELOPING WHERE THIS FLOW MOISTENED
BY LAKE SUPERIOR WILL UPSLOPE AT KIWD/KSAW.
&&
.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 357 AM EST TUE FEB 26 2013
A RIDGE OF HIGH PRESSURE ACROSS LAKE SUPERIOR WILL PUSH NORTHWARD
TODAY...IN ADVANCE OF WEAKENING LOW PRESSURE SLIDING FROM SOUTHERN
MISSOURI THIS MORNING TO FAR SOUTHEASTERN LOWER MICHIGAN AND OHIO
WEDNESDAY MORNING...AND EXITING ACROSS NEW YORK WEDNESDAY NIGHT. AS
A RESULT...EXPECT A TROUGH OVER LAKE SUPERIOR WITH STEADY N-NE WINDS
FROM MID AFTERNOON THROUGH THE REST OF THE WORK WEEK. THE STRONGEST
WINDS...WITH A FEW GUSTS NEARING 35KTS CAN BE EXPECTED WEDNESDAY
INTO THURSDAY AS LAKE SUPERIOR BECOMES PINNED BETWEEN THE LOW
PRESSURE SYSTEM TO OUR SOUTHEAST AND STRONG HIGH PRESSURE EDGING IN
FROM THE NORTHWEST. GIVEN THE STRONGER WINDS AND COOLER AIR SLIDING
IN...FREEZING SPRAY WILL BE POSSIBLE. HIGH PRESSURE WILL WIN OUT
FRIDAY...WITH A RIDGE RESIDING ACROSS LAKE SUPERIOR THROUGH AT LEAST
SATURDAY NIGHT.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...KC
LONG TERM...KF
AVIATION...ROLFSON
MARINE...KF
AREA FORECAST DISCUSSION
NWS GRAND RAPIDS MI
1122 AM EST TUE FEB 26 2013
.SYNOPSIS...
ISSUED AT 324 AM EST TUE FEB 26 2013
A STORM SYSTEM GATHERING STRENGTH ACROSS ARKANSAS EARLY THIS MORNING
WILL APPROACH LOWER MICHIGAN THIS AFTERNOON AND EVENING.
PRECIPITATION WILL DEVELOP ACROSS THE AREA FROM SOUTH TO NORTH
DURING THE AFTERNOON AND EVENING HOURS. A MIXTURE OF RAIN...SNOW...
AND SOME SLEET WILL BE POSSIBLE AS PRECIPITATION DEVELOPS. ALL
PRECIPITATION WILL QUICKLY CHANGE OVER TO SNOW. SNOW ACCUMULATIONS
WILL RANGE FROM 2 INCHES OR SO UP NORTH...TO 6 INCHES DOWN SOUTH BY
WEDNESDAY MORNING. LIGHT SNOW WILL CONTINUE WEDNESDAY AND WEDNESDAY
NIGHT WITH ONLY LIGHT ADDITIONAL ACCUMULATIONS EXPECTED.
&&
.UPDATE...
ISSUED AT 1117 AM EST TUE FEB 26 2013
WITH THE WARM LAYER FURTHER NORTH...MORE OF A MIX MENTIONED IN THE
FORECAST FOR THIS AFTERNOON. THIS MIX WILL CUT INTO THE OVERALL
SNOW AMOUNTS...ESPECIALLY ALONG I 94. WHILE AIR TEMPERATURES HAVE
RISEN ABOVE FREEZING...AS THE PRECIPITATION MOVES IN WE WILL WET
BULB DOWN TO THE LOW 30S. AS A RESULT FREEZING RAIN COULD OCCUR. UPDATES
TO THE PRODUCTS HAVE BEEN ISSUED.
&&
.SHORT TERM...(TODAY THROUGH THURSDAY)
ISSUED AT 324 AM EST TUE FEB 26 2013
MAIN FOCUS OF THE FCST IS OBVIOUSLY THE INCOMING SYSTEM AND
EVALUATING WHETHER ANY ADJUSTMENTS ARE NEEDED TO THE GOING
HEADLINES. AT THIS TIME...WE WILL BE HOLDING ON TO THE ADVISORY AS
IT IS AS THERE IS NOT A GOOD REASON TO CHANGE THINGS FOR NOW.
THE LATEST MODEL RUNS FROM THE 00Z CYCLE ARE PRETTY MUCH MAINTAINING
GOOD CONTINUITY FROM THEIR PREVIOUS RUNS. WE ARE STILL EXPECTING A
NICE AND POSSIBLY HEAVY BURST OF PCPN INITIALLY BY MID AFTERNOON
DOWN SOUTH ALONG I-94...AND SPREADING NORTH INTO THE MID EVENING
HOURS TONIGHT. THIS BURST IS THE RESULT OF STRONG ISENTROPIC
ASCENT/MOISTURE TRANSPORT ALOFT OUT AHEAD OF THE SYSTEM AND
RESULTING STRONG FGEN DEVELOPING AS A RESULT. WE CONTINUE
TO SEE A GOOD CROSS-HAIRS SIGNATURE WHERE THE BEST LIFT OCCURS IN THE
DGZ. IN ADDITION...A WEAKNESS IN THE STABILITY DOES EXISTS WHICH
WILL ONLY ENHANCE THE BAND OF PCPN. IT SHOULD BE MENTIONED THAT A
GOOD PORTION OF THE STORM TOTALS ARE EXPECTED TO COME FROM THIS
HEAVY BURST THIS AFTERNOON/EVENING. LOW SNOW TO WATER RATIOS WILL
LIMIT SNOW ACCUMULATIONS SOME. THE HEAVIER BAND OF PCPN SHOULD
PRODUCE BRIEFLY HIGHER SNOW TO WATER RATIOS WITH THE DGZ AND LIFT
COINCIDING.
THE MAIN CONCERN IN THE WHOLE EVENT THAT WE ARE MONITORING IS THE
POTENTIAL FOR A LITTLE MORE POSSIBLE RAIN AT THE ONSET DOWN SOUTH. A
COUPLE OF THE MODELS...SPECIFICALLY THE NAM AND GEM ARE INDICATING A
BIT BETTER CHC OF RAIN DOWN SOUTH THIS AFTERNOON AND EARLY EVENING
BEFORE ALL PCPN CHANGES OVER TO SNOW DUE TO EVAPORATIVE COOLING. THE
GFS AND EURO EACH BRING SUFFICIENTLY DEEP WET BULB ZERO HEIGHTS
ALMOST TO I-94 BEFORE EVAPORATIVE COOLING WIPES THAT OUT BY MID
EVENING. WE ARE LEANING HEAVILY TOWARD THE GFS AND EURO AT THIS TIME
AS THEY HAVE BEEN VERY CONSISTENT. WE HAVE ADDED IN/MAINTAINED A CHC
OF RAIN ACROSS THE FAR SOUTH IN THE EVENT THAT THE WET BULB ZERO
HEIGHTS ARE JUST DEEP ENOUGH TO ALLOW FOR SOME RAIN. SLEET REMAINS
POSSIBLE STILL ALSO AT THE ONSET DOWN SOUTH WITH A WARM NOSE ALOFT
AND THEN A COLD LAYER BEFORE A SLIGHTLY ABOVE FREEZING SFC TEMP.
WE WILL SEE THE ISENTROPIC ASCENT BURST OF PCPN SHIFT NORTH AND EAST
THIS EVENING BEFORE WEAKENING AND MOVING OUT AS THE MAIN PUSH OF
WARMTH AND MOISTURE SHIFTS SE WITH THE TRANSFER OF ENERGY EXPECTED
TO TAKE PLACE THIS EVENING. WE STILL EXPECT TO SEE A LULL IN THE
SNOW BEFORE IT WILL PICK UP ONCE AGAIN SOME LATER IN THE EVENING AND
OVERNIGHT AS THE DEFORMATION ZONE/TROWAL MOVES INTO THE AREA. THE
SECOND ROUND IS EXPECTED TO BRING LIGHTER ACCUMULATIONS THAN THE
INITIAL BURST FOR MANY LOCATIONS. THERE WILL BE NO P-TYPE ISSUES
WITH THIS ROUND AS EVAPORATIVE COOLING WILL MAKE THE ENTIRE COLUMN
COLD ENOUGH FOR SNOW.
WE WILL SEE THE SNOW TAPER OFF SOME THEN FOR WED AND WED NIGHT.
HOWEVER WE WILL CONTINUE TO SEE INTERVALS OF LIGHT SNOW AS THE UPPER
LOW GETS HUNG UP TO OUR EAST AND WE WILL REMAIN CYCLONIC ALOFT. THIS
IS SOMEWHAT SIMILAR TO THE EVENT LATE LAST WEEK DUE TO THE UPPER
LOW. IT IS DIFFERENT IN THE SENSE THAT THERE WILL NOT REALLY BE A
LAKE CONTRIBUTION DUE TO H850 TEMPS NOT BEING COLD ENOUGH AND THAT
THE FLOW WILL REMAIN OFFSHORE THROUGH WED NIGHT. ACCUMULATIONS
SHOULD BE LIMITED TO AROUND AN INCH OR SO FOR EACH WED AND THEN
AGAIN WED NIGHT. THE UPPER LOW WILL PULL AWAY ON THU AND GRADUALLY
TAKE THE SNOW CHANCES EAST OF THE AREA THROUGH THE DAY.
.LONG TERM...(THURSDAY NIGHT THROUGH MONDAY)
ISSUED AT 324 AM EST TUE FEB 26 2013
FOR NOW I WILL CONTINUE OUR IDEA OF A PERIOD OF PRECIPITATION FREE
WEATHER FOR SOUTHWEST MICHIGAN FROM FRIDAY INTO MONDAY. TEMPERATURES
WILL BE COLDER THAN NORMAL DURING THIS TIME PERIOD.
MY CONFIDENCE IN THIS FORECAST IS A LITTLE LESS THAN YESTERDAY SINCE
EVEN THOUGH THE MODELS HAVE BEEN SOMEWHAT CONSISTENT WITH THE
LONG WAVE PATTERN FORECAST...THERE ARE NUMEROUS DETAIL ISSUES AS TO
HOW INDIVIDUAL SHORTWAVES ARE HANDLED AS THEY MOVE THROUGH THE MEAN
WESTERN RIDGE INTO THE CENTRAL GREAT LAKES.
TWO LARGE SCALE FEATURES WORK TOGETHER TO CREATE AN AMPLIFIED UPPER
AIR PATTERN OVER THE CONUS DURING THIS TIME PERIOD. THERE IS A
POWERFUL PACIFIC STORM APPROACHING THE DATELINE (AS I WRITE THIS)
THAT BOOTS THE SYSTEM ALREADY THERE DOWNSTREAM OVER THE WESTERN
RIDGE INTO WEST CENTRAL CONUS IN THE FRI/SAT TIME FRAME. SINCE THE
STORM HEADING TOWARD THE DATELINE IS POWERFUL STORM...IT ENDS UP
BUILDING THE WESTERN RIDGE EVEN STRONGER THAN IT CURRENTLY IS. THAT
HELPS TO CREATE MORE NORTHERLY FLOW AT MID AND UPPER LEVELS OVER
CENTRAL NORTH AMERICA. MEANWHILE THERE IS A LARGE BLOCKING UPPER
HIGH EAST OF GREENLAND THAT IS CURRENTLY RETROGRADING. THAT IS
FORCING ANY SYSTEMS SOUTH OF IT. THE COMBINATION OF THOSE TWO
SYSTEMS...ONE OVER THE NORTH ATLANTIC AND THE OTHER OVER THE NORTH
PACIFIC...WILL PROVIDE A STEADY SUPPLY OF COLD (BUT NOT ARCTIC) AIR
INTO EARLY NEXT WEEK DUE TO THE LARGELY NORTH NORTHWEST FLOW AT
UPPER LEVELS DURING THAT TIME.
ANOTHER ASPECT TO THIS IS THE EXTENSION OF THE HUDSON BAY HIGH INTO
LOWER MICHIGAN INTO THIS COMING WEEKEND. THAT CREATES A NORTH
NORTHEAST SURFACE WIND FLOW. THAT IN TURN WILL KEEP ANY LAKE EFFECT
ON THE WISCONSIN SIDE OF LAKE MICHIGAN INTO EARLY NEXT WEEK.
THE ONLY REAL ISSUE IS THAT THERE ARE SEVERAL MINOR SHORTWAVES
MOVING THROUGH THE UPPER LEVEL FLOW DURING THIS TIME PERIOD. IT IS
POSSIBLE IF ONE OF THOSE SHORTWAVES GOT A TOUCH MORE AMPLIFIED WE
COULD BE SEEING AND EXTEND PERIOD OF LIGHT SNOW. NOW THOUGH IT LOOKS
LIKE ANY SYSTEMS WILL STAY WEST AND SOUTH OF LOWER MICHIGAN...
BRINGING LARGELY DRY BUT COLD WEATHER.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z WEDNESDAY MORNING)
ISSUED AT 647 AM EST TUE FEB 26 2013
LITTLE QUESTION THE CURRENT VFR CIGS/VSBY WILL GO TO SOLID IFR
CIGS/VSBY BY 00Z WITH SNOW ACROSS ALL TAF SITES.
THE TIMING WAS FOR WHEN THE PRECIPITATION REACHES EACH TAF SITE
AND THE TIMING OF THE CHANGE FROM RAIN TO SNOW WAS BASED ON
COMBINATION OF THE HRRR AND 06Z NAM12 RADAR FORECASTS WITH SOME
CONSIDERATION TO HOW WELL THOSE FORECAST FIELDS MATCH THE CURRENT
PRECIPITATION PATTERN. BOTH ARE SIMILAR ON TIMING AND DO A GOOD
JOB OF MATCHING WERE THE PRECIPITATION HAS BEEN THE PAST FEW
HOURS. THE HRRR IS MUCH MORE RELUCTANT TO CHANGE THE RAIN TO
SNOW... IN FACT THE HRRR HAS NO SNOW OVER ANY PART OF THE CWA
THROUGH 00Z... IT SHOWS ALL RAIN. CURRENTLY (11Z) THE RAIN TO SNOW
LINE IS IN CENTRAL ILLINOIS... THE HRRR HAS IT EASTERN IOWA. THE
RAIN/SNOW LINE IS BETTER MATCHED ON THE NAM12 WHICH HAS IT WHERE
IT CURRENTLY IS. SO... I USED THAT FOR MY RAIN TO SNOW DECISION MAKING IN
THE TAFS. ONCE THE PRECIPITATION BEGINS... IT WILL QUICKLY LOWER
THE CEILING TO IFR AND WITH THE SLOW MOVEMENT OF THE SYSTEM THE
IFR CIGS/VSBY WILL CONTINUE THROUGH THE NIGHT INTO WEDNESDAY.
&&
.MARINE...
ISSUED AT 1117 AM EST TUE FEB 26 2013
NO MAJOR CHANGES. WINDS HAVE RISEN TO SCA CRITERIA. WILL BE CLOSE
TO GALES AT TIMES.
&&
.HYDROLOGY...
ISSUED AT 324 AM EST TUE FEB 26 2013
THE ONLY THING OF CONCERN IN HYDROLOGY REMAINS THE POTENTIAL FOR ICE
JAMS. THERE HAS BEEN NOTHING TO NOTE IN THE LAST COUPLE OF DAYS. WE
WILL CONTINUE TO MONITOR FOR ANY POTENTIAL PROBLEMS THAT MAY CROP UP
AS MILD TEMPS WORK ON ANY ICE ON THE RIVERS AND STREAMS.
&&
.GRR WATCHES/WARNINGS/ADVISORIES...
MI...WINTER WEATHER ADVISORY UNTIL 6 AM EST WEDNESDAY FOR MIZ064>067-
071>074.
WINTER WEATHER ADVISORY FROM 4 PM THIS AFTERNOON TO 6 AM EST
WEDNESDAY FOR MIZ044>046-050>052-056>059.
LM...SMALL CRAFT ADVISORY UNTIL 7 AM EST THURSDAY FOR LMZ844>849.
&&
$$
UPDATE...MJS
SYNOPSIS...NJJ
SHORT TERM...NJJ
LONG TERM...WDM
AVIATION...WDM
HYDROLOGY...NJJ
MARINE...MJS
AREA FORECAST DISCUSSION
NWS TWIN CITIES/CHANHASSEN MN
233 PM CST TUE FEB 26 2013
.DISCUSSION...
INITIAL CONCERN IS CLOUD COVER OVERNIGHT. DRIER WEDGE IN LOWER
LEVEL CIRCULATING AROUND STORM TO THE SOUTH WAS STRONG ENOUGH THIS
AFTERNOON TO ERODE CLOUDS SOME. ANOTHER SURGE OF MOISTURE APPEARS
TO BE WORKING ACROSS THE UP AND NORTHEAST WI AND IS NOW MOVING
ACROSS WEST CENTRAL WI. LATEST RAP HAS THIS WORKING SOUTHWEST LATE
AFTERNOON INTO THE EVENING...AFFECTING MAINLY SOUTH CENTRAL MN.
STRATUS AND FOG IS NOW ERODING FROM THE NORTH AS WELL...IN DRIER
AIR FLOW OVER NORTHEAST MN. DIFFICULT TO DISCERN HOW FAR SOUTH
AND WEST THIS WILL GO. MODELS TREND MUCH DRIER IN THE 925-850MB
LAYER OVER THE WESTERN AREAS. STILL BELIEVE SIGNIFICANT AMOUNT OF
MID/HIGH CLOUDS WILL CONTINUE TO STREAM NORTH AND WEST OVER NIGHT
AND SHOULD MAINTAIN AT LEAST A MOSTLY CLOUDY SKY OVER MOST OF THE
AREA. FOG SHOULD BE LIMITED TO THE FAR WEST INTO THE EVENING...AND
SHOULDNT BECOME DENSE OR AS WIDESPREAD WITH THE GRADIENT
INCREASING AS WELL AS THE SURFACE WINDS OVERNIGHT.
CONCERN NUMBER TWO REMAINS HOW FAR NORTHWEST SNOW WILL DEVELOP
MAINLY DURING THE DAY WEDNESDAY. MODELS FAIRLY CONSISTENT ON
DRAGGING SNOW INTO FAR SOUTHEAST CWA...WITH THE NAM REMAINING THE
DRIEST. THE GFS IS FARTHER WEST INTO OUR CWA...WITH THE 12Z GEM
AND ECMWF CONFINING POSSIBILITY TO THE FAR SOUTHEAST CORNER OF THE
AREA. IT ALL HINGES ON HOW THE SECONDARY UPPER TROUGH MOVES ACROSS
KANSAS AND MERGES WITH THE UPPER LOW MOVING OVER THE OHIO RIVER
RIVER VALLEY. WILL CONTINUE THE TREND OF LOW END CHANCE POPS OVER
THAT REGION THROUGH WEDNESDAY.
SHOULD SEE SOME CLEARING INTO WEDNESDAY NIGHT FOLLOWING THE STORM
SYSTEM TO THE SOUTHEAST...BUT MODELS TREND ANOTHER SHORT WAVE
DROPPING SOUTHEAST OVER THE DAKOTAS AND MINNESOTA...THURSDAY INTO
FRIDAY. THIS SHOULD YIELD AT LEAST MORE CLOUDS AND THE THREAT OF
SOME FLURRIES...MAINLY OVER THE WESTERN AREAS. THE 12Z ECMWF IS
NOT AS AMPLIFIED WITH THIS FEATURE AND IS A BIT DRIER...SO WILL
LEAVE FLURRY MENTION OUT FOR NOW.
HIGH TEMPERATURES FORECAST SLIGHTLY BELOW NORMAL INTO THE
WEEKEND. NEXT STRONG TROUGH MOVES ASHORE ON THE WEST COAST OVER
THE WEEKEND. LONGER TERM MODELS BRINGING THIS NEXT WAVE/TROUGH
INTO THE AREA MAINLY SUNDAY NIGHT INTO TUESDAY. HAVE INCLUDED
SMALL CHANCE POPS FOR THIS FEATURE AS IT MOVES THROUGH THE AREA
FOR NOW. COULD BE WARM ENOUGH FOR A POSSIBLY MIX AS THE SYSTEM
WORKS INTO THE AREA...AT LEAST INITIALLY.
&&
.AVIATION.../18Z TAF ISSUANCE/
AREAS OF DENSE FOG HAS SLOWLY DISSIPATED ACROSS FAR WESTERN MN AS
OF 11 AM. ONLY COUNTIES ALONG THE SD HAVE VSBYS NEAR 1/4SM...BUT
OUTSIDE OF MPX TAF SITES. SHORT TERM CONCERNS DEAL WITH CIGS
RISING TO MVFR/VFR THIS AFTN... AND WHETHER THERE WILL BE ANOTHER
REPEAT OF THE DENSE FOG OVERNIGHT...ESPECIALLY FOR AXN.
PRESSURE GRADIENT HAS FINALLY INCREASED ENOUGH TO PRODUCE A
PREDOMINATE WIND DIRECTION FROM THE E/NE ACROSS MOST OF THE FA.
ONLY THE FAR NW HAS MORE INFLUENCE OF THE DEPARTING SFC RIDGE IN
NE MN. SATELLITE IMAGERY HAS NOTED THE DECREASING LOW CLDS IN THE
WEST WITH MORE MVFR CIGS ACROSS EC MN/WC WI. ANOTHER AREA OF MVFR
CIGS WAS NOTED ACROSS EASTERN WI...WHICH MAY INFLUENCE OR CAUSE
MORE MVFR CIGS IN WI/EC MN THIS EVENING. OTHERWISE...EXPECT A
BETTER AVIATION FORECAST IN TERMS OF HIGHER CIGS/VSBYS THAN IN THE
PREVIOUS 48 HRS AS THE PATTERN CHGS. EVEN SOME -SN IS POSSIBLE IN
EAU BY THE END OF THE TAF PERIOD. ONLY AXN HAS A CHC OF REPEATING
THE LIFR/VLIFR CIGS/VSBYS DURING THE OVERNIGHT HRS. WINDS WILL BE
GENERALLY FROM THE NE/ENE THIS AFTN ARND 6-12 KTS...THEN BEGIN TO
INCREASE AND SHIFT TO THE NNE/N BY MORNING...WITH GUSTY WINDS
DEVELOPING BY 15Z.
KMSP...
WILL CONTINUE THE SAME SCENARIO OF MVFR CIGS LIFTING BY 20Z...BUT
ENOUGH MOISTURE AND CONFIDENCE AFT 20Z IS LOW TO TOTALLY BRING IN
VFR. IN ADDITION...MORE MVFR CIGS ACROSS EASTERN WI MAY BEGIN TO
AFFECT THE AIRPORT TERMINAL AFT 2-4Z...WITH THE BEST TIME FRAME
TOWARD MIDNIGHT. THESE MVFR CIGS WILL LIKELY CONTINUE THRU MOST OF
THE TAF PERIOD WITH WINDS BECOMING MORE N/NNW WED MORNING...AND
GUSTY BY AFTN.
/OUTLOOK FOR KMSP/
THU...VFR WITH MVFR CIGS POSSIBLE. N WINDS AT 10KTS.
FRI...VFR WITH MVFR CIGS POSSIBLE. N WINDS AT 8KTS.
SAT...VFR. LIGHT N/NE WIND. ..JLT..
&&
.MPX WATCHES/WARNINGS/ADVISORIES...
MN...NONE.
WI...NONE.
&&
$$
DWE/JLT
AREA FORECAST DISCUSSION
NWS KANSAS CITY/PLEASANT HILL MO
1112 AM CST Tue Feb 26 2013
...UPDATED AVIATION DISCUSSION...
.UPDATE...
/901 AM CST Tue Feb 26 2013/
Have adjusted POPs based on latest radar trends. The storm seems to
have peaked and we are currently seeing dry air entrain into the
system from east, associated with the dry slot. This led to more
spotty precipitation in our eastern zones. So pops have been
decreased some there for the rest of the day. The main deformation
area is rotating through western and northwestern Missouri. This
should continue to be the case through the early afternoon so have
increased precipitation chances in that area. The IR satellite
depiction shows cloud tops have been warming which indicates a
weakening trend in the storm. This has led to radar returns
diminishing in intensity as well. Overall, the heaviest snow over the
next several hours will be across our northwestern zones from Kansas
City northward.
.DISCUSSION...
/400 AM CST Tue Feb 26 2013/
Today and Wednesday...
The ongoing winter storm continues to be the main focus for this
forecast issuance. Primary changes to the forecast are to increase
snow amounts in north central and northeast Missouri into the 10-12
inch range, with locally higher amounts possible. Snow totals have
also decreased across northwest Missouri, where snow may not start
until after sunrise and only a few inches of snow accumulation are
expected later this morning.
The deformation zone along the northeast side of a deepening surface
low has set up across the southeastern half of the forecast area,
and appears to be pivoting along a line from the southern KC metro
to Kirksville. The highest snowfall totals should occur within this
band and areas to the southeast, although melting and compaction may
work to decrease overall totals across the area. By 12z-15z, the
main PV anomaly will begin to kick east of the CWA, separating the
upper-level forcing from low- to mid-level frontogenesis and thus
likely decreasing snowfall rates/intensity by mid-morning. However,
at least some lift will linger in the trowal and support continued
light to moderate snowfall, especially over northeast and north
central Missouri. The RAP and latest NAM indicate that as the trowal
pivots northward this morning, light snowfall may finally edge into
the northwest corner of the CWA. Dynamics may start to weaken by the
time snowfall can start in the northwest and residence time over the
area will be much shorter, keeping snowfall totals in the 1-3 inch
range along and northwest of a line from St. Joseph to Sheridan MO.
A secondary wave will drop east southeast into southern portions of
the forecast area by late tonight, allowing some additional light
snowfall to form over northeast Kansas and west central Missouri.
This wave will wrap into the main upper low on Wednesday, allowing
light snowfall to shift eastward and eventually exit the region on
Wednesday afternoon. Additional snowfall amounts should be around an
inch or less, due to some depletion of low-level moisture and a lack
of any mesoscale features to enhance the weaker, broad-scale upper
forcing.
Temperatures today should be relatively steady throughout the day
and evening, dropping only a few degrees by tonight as slightly
cooler air filters in behind the low. Highs on Wednesday may rise a
few degrees in the northwest where a few breaks of sunshine and
lesser snow cover may allow for a bit more warming, but should hover
near freezing across the remainder of the area.
Laflin
Wednesday Night and Thursday...
The deep upper low responsible for our Tuesday winter storm will
have moved into the Mid Atlantic States during this period pulling
the extensive cloud shield with it. This should lead to at least a
partial clearing from west to east on Thursday. Temperatures will
remain below average as pronounced northerly fetch with weak high
pressure builds into the central CONUS.
Medium Range (Friday through Monday)...
The upper pattern will be characterized by a pronounced upper ridge
building eastward across the Rockies with a deepening trough over
from the TN into the Lower MS Valley. In between dry northwest flow
aloft will maintain well below average temperatures through Sunday.
Prefer to use the GFS Ensemble Mean h5 field for early next week due
to timing/evolution differences between the ECMWF and GFS of a fairly
strong upper wave dropping southeast through the Intermountain
Region Sunday night. This feature could reach the Central High
Plains on Monday with increasing warm air advection aiding
development of downstream precipitation which could affect the CWA
by Monday night. For now a model average works best with a moderate
increase in PoPs for Monday night.
MJ
&&
.AVIATION...
For the 18Z TAFs, conditions are beginning to improve at the terminals
with the main deformation band continuing to weaken and drift
westward. There may be some light snow showers move through the KC
terminals but any impact would be short-lived and minor. Otherwise
conditions may improve to MVFR late this afternoon. Another, weaker
system will move through the region tonight and will bring another
round of light to possibly moderate snow to the area. Have trended
back to IFR cigs for this snow but given what will be a much
lighter snow event have only reduced vsby to 1 to 2 miles. This snow
should move east of terminals mid Wednesday morning with conditions
then improving through the last few hours of the forecast.
CDB
&&
.EAX WATCHES/WARNINGS/ADVISORIES...
MO...WINTER STORM WARNING until 3 PM CST this afternoon FOR MOZ004-
012>014-020>022-028>031-037>039-043>046-053-054.
WINTER STORM WARNING until 9 PM CST this evening FOR MOZ005>008-
015>017-023>025-032-033-040.
WINTER WEATHER ADVISORY until 3 PM CST this afternoon FOR
MOZ001>003-011.
KS...WINTER STORM WARNING until 3 PM CST this afternoon FOR KSZ025-
057-060-102>105.
&&
$$
WFO EAX
AREA FORECAST DISCUSSION
NWS GREAT FALLS MT
1130 AM MST Tue Feb 26 2013
.DISCUSSION...
Update forthcoming. Have adjusted qpf and snow amounts this morning.
Otherwise, current forecast looks good. Moist unstable northwest
flow aloft over the area contributing to areas of light snow. Radar
showing heaviest band just east of Great Falls. RUC indicates snow
will gradually end by late afternoon. Temperatures look reasonable.
Emanuel
&&
.AVIATION...
Updated 1830Z.
Scattered light snow showers will affect Central Montana through
21z...with brief periods of IFR conditions in heavier snow showers.
Expect partial clearing tonight...with most areas under VFR
conditions. Some mountains will be obscured at times through the
afternoon...especially over Central MT from Great Falls to
Lewistown. Brusda
&&
.PREV DISCUSSION...ISSUED 411 AM MST Tue Feb 26 2013
Today through Thursday...An upper level trough axis extends from
Alberta south through the U.S. Rockies this morning. Main energy
within the trough is diving southeast through UT while a weaker
embedded vorticity center looks to be centered along the MT/AB
border per satellite imagery this morning. A moist NW flow aloft
will continue over the region today as the upper trough axis
shifts east across MT, keeping the threat for occasional showers
going over the mtns through most of today. The weak upper level
feature along the Canadian border will also track east today with
an associated shift to NW winds at the surface pushing southeast
through North Central MT this morning. Expect a period of light
snow showers or flurries across portions of North Central MT as
this feature moves through this morning and early this afternoon.
Little or no snow accumulation is anticipated at lower elevations
with around an inch of new snow accumulation possible in the
mountains today. A transient upper level ridge will drift east
across the region tonight through Wednesday morning bringing an
end to shower activity this evening along with clearing skies.
Another shortwave in progressive westerly flow aloft is forecast
to move east into the Northern Rockies late Wednesday, then dive
southeast across MT Wednesday night and Thursday. This will bring
increasing clouds to the forecast area again Wednesday afternoon
with precipitation developing over the mountains again Wednesday
night and continuing through Thursday as additional shortwave and
upper level Jet energy streams across the Northern Rockies. Most
of the precipitation during this period will be over the
mountains with west to southwest surface winds keeping the
Plains/Valleys dry. Temperatures will be slightly below seasonal
averages today with gradual warming Wednesday and Thursday.
Thursday night through Tuesday...Consistency amongst the models
is good into the first part of the weekend. Also for a particular
model..run-to-run consistency is good. So expect northwest flow
aloft Thursday night through Friday night with an upper ridge moving
over the forecast area on Saturday. Will continue with the idea of
scattered snow showers over the mountains at first then diminishing
as the upper ridge approaches. Model consistency for a weather
system for Sunday through Monday has increased with latest model
runs. The associated cold front is expected to move through the
forecast area Sunday while the upper trough moves in Sunday night.
This system looks fairly wet so have increased the chances of snow
but did not go too high with the chances as there still are
differences with regard to model forecast precipitation patterns. In
line with the increased threat for precipitation have also lowered
high temperatures for Monday. By Tuesday the next upper ridge is
forecast to move into western if not central Montana and in
comparison to Monday have lowered the chances of snow and moderated
temperatures slightly. Blank
&&
.PRELIMINARY POINT TEMPS/POPS...
GTF 38 20 42 25 / 50 0 10 10
CTB 37 19 43 23 / 40 0 0 10
HLN 38 18 39 24 / 20 10 10 20
BZN 32 11 34 16 / 30 10 10 20
WEY 28 3 27 9 / 50 20 20 30
DLN 32 11 35 16 / 10 0 10 20
HVR 34 16 38 22 / 40 10 0 10
LWT 31 12 38 18 / 30 20 10 20
&&
.TFX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
weather.gov/greatfalls
AREA FORECAST DISCUSSION
NWS GREAT FALLS MT
10 AM MST Tue Feb 26 2013
.DISCUSSION...
Update forthcoming. Have adjusted qpf and snow amounts this morning.
Otherwise, current forecast looks good. Moist unstable northwest
flow aloft over the area contributing to areas of light snow. Radar
showing heaviest band just east of Great Falls. RUC indicates snow
will gradually end by late afternoon. Temperatures look reasonable.
Emanuel
&&
.AVIATION...
Updated 1150Z.
A weather disturbance aloft will be moving through the area today.
It will bring a few snow showers to the lower elevations with more
numerous snow showers over the mountains. Expect some obscurement of
the mountains while lower elevations could see MVFR or possibly even
IFR conditions in the snow showers. With the snow showers do not
expect MVFR/IFR visibilities to last more than an hour. Do not think
there is much threat of MVFR conditions at KHLN and KBZN so did not
include their mention in those two tafs. The main message for late
this afternoon and evening is improving conditions and should see
mostly clear skies by midnight. Although not mentioned in the tafs
there is remote threat of freezing fog at KHVR and KHLN late tonight.
Blank
&&
.PREV DISCUSSION...ISSUED 411 AM MST Tue Feb 26 2013
Today through Thursday...An upper level trough axis extends from
Alberta south through the U.S. Rockies this morning. Main energy
within the trough is diving southeast through UT while a weaker
embedded vorticity center looks to be centered along the MT/AB
border per satellite imagery this morning. A moist NW flow aloft
will continue over the region today as the upper trough axis
shifts east across MT, keeping the threat for occasional showers
going over the mtns through most of today. The weak upper level
feature along the Canadian border will also track east today with
an associated shift to NW winds at the surface pushing southeast
through North Central MT this morning. Expect a period of light
snow showers or flurries across portions of North Central MT as
this feature moves through this morning and early this afternoon.
Little or no snow accumulation is anticipated at lower elevations
with around an inch of new snow accumulation possible in the
mountains today. A transient upper level ridge will drift east
across the region tonight through Wednesday morning bringing an
end to shower activity this evening along with clearing skies.
Another shortwave in progressive westerly flow aloft is forecast
to move east into the Northern Rockies late Wednesday, then dive
southeast across MT Wednesday night and Thursday. This will bring
increasing clouds to the forecast area again Wednesday afternoon
with precipitation developing over the mountains again Wednesday
night and continuing through Thursday as additional shortwave and
upper level Jet energy streams across the Northern Rockies. Most
of the precipitation during this period will be over the
mountains with west to southwest surface winds keeping the
Plains/Valleys dry. Temperatures will be slightly below seasonal
averages today with gradual warming Wednesday and Thursday.
Thursday night through Tuesday...Consistency amongst the models
is good into the first part of the weekend. Also for a particular
model..run-to-run consistency is good. So expect northwest flow
aloft Thursday night through Friday night with an upper ridge moving
over the forecast area on Saturday. Will continue with the idea of
scattered snow showers over the mountains at first then diminishing
as the upper ridge approaches. Model consistency for a weather
system for Sunday through Monday has increased with latest model
runs. The associated cold front is expected to move through the
forecast area Sunday while the upper trough moves in Sunday night.
This system looks fairly wet so have increased the chances of snow
but did not go too high with the chances as there still are
differences with regard to model forecast precipitation patterns. In
line with the increased threat for precipitation have also lowered
high temperatures for Monday. By Tuesday the next upper ridge is
forecast to move into western if not central Montana and in
comparison to Monday have lowered the chances of snow and moderated
temperatures slightly. Blank
&&
.PRELIMINARY POINT TEMPS/POPS...
GTF 38 20 42 25 / 50 0 10 10
CTB 37 19 43 23 / 40 0 0 10
HLN 38 18 39 24 / 20 10 10 20
BZN 32 11 34 16 / 30 10 10 20
WEY 28 3 27 9 / 50 20 20 30
DLN 32 11 35 16 / 10 0 10 20
HVR 34 16 38 22 / 40 10 0 10
LWT 31 12 38 18 / 30 20 10 20
&&
.TFX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
weather.gov/greatfalls
AREA FORECAST DISCUSSION...UPDATED
NWS GRAND FORKS ND
1008 AM CST TUE FEB 26 2013
.DISCUSSION...
MAIN QUESTION TODAY IS THE FOG/STRATUS AND HOW IT MAY AFFECT
HIGHS. A THIN FINGER OF THIS LAYER HAS PUSHED ALL THE WAY UP
TOWARD KHCO. SOME METARS ARE STILL REPORTING A QUARTER MILE VSBY
WHILE OTHER WEB CAMS NEARBY SHOW DECENT VSBYS. SINCE VSBYS ARE NO
LONGER A CONSISTENT QUARTER MILE WENT AHEAD AND LET THE DENSE FOG
ADVISORY EXPIRE. SHOULD SEE LOTS OF SUN TODAY IN THE NORTHEAST AND
NORTHWEST WHERE TEMPS SHOULD RISE ABOVE 32F AGAIN. TWEAKED HIGHS
UP A BIT AROUND THE LAKE OF THE WOODS AND BEMIDJI AREAS AND
LOWERED THEM A LITTLE IN THE IMMEDIATE RED RIVER VALLEY.
&&
.AVIATION...
SEEING HIGHLY VARIABLE VSBYS JUST LIKE YESTERDAY. TODAY KGFK AND
KFAR WILL BE THE SITES THAT NEED TO BE WATCHED CLOSER THIS MORNING
WHILE THE OTHER SITES REMAIN VFR. FOR KFAR/KGFK WILL GO WITH
CONTINUED IMPROVEMENT THRU THE REST OF THE MORNING.
&&
.PREV DISCUSSION... /ISSUED 340 AM CST TUE FEB 26 2013/
SHORT TERM...
THE MAIN CHALLENGE WILL BE FOG AND LOW CLOUDS THROUGH THIS
MORNING...THEN VERY LIGHT SNOW/FLURRY CHANCES WED/WED NIGHT INTO
THU PERHAPS. ALL MODELS ARE DOING POORLY WITH CURRENT LOW CLOUD/FOG
ALONG AND EAST OF THE VALLEY. THE HRRR IS DOING THE BEST AND WILL
FOLLOW THAT FOR THE NEAR TERM. THEREAFTER...MOST MODELS ARE
SIMILAR WITH NO REAL PREFERENCE.
FOR TODAY...THE BIG QUESTION WILL BE HOW LONG DOES THE DENSE FOG
PERSISTS AND ASSOCIATED LOW CLOUDS ALONG AND EAST OF THE RED RIVER
VALLEY. WE WILL CONTINUE TO MONITOR THE POSSIBLE NORTHWARD
EXPANSION OF THE CURRENT DENSE FOG ADVISORY...WITH CLOUDS HOLDING
DOWN TEMPS WHERE THEY PERSIST TODAY. A WEAK SFC HIGH BUILDS IN
WITH RIDGING ALOFT...LENDING MORE CREDENCE TO CLOUDS/FOG
PERSISTING TODAY WHERE THEY ARE AT SUNRISE.
FOR TONIGHT...WEAK CAA BEGINS IN THE NW AND THERE COULD BE FOG/LOW
CLOUDS IN THE SOUTH AND EAST. FOR NOW WON/T MENTION ANY FOG...BUT
MONITOR WITH LATER FORECASTS. TEMPS WILL BE HIGHLY DEPENDENT ON
HOW MUCH CLEARING DEVELOPS.
ON WED/WED NIGHT...THERE WILL BE LOW LEVEL SATURATION UP TO AROUND
800MB IN THE NORTH ADVECTING SOUTH. THERE SHOULD BE AN AREA OF
LIGHT SNOW/FLURRIES MAINLY IN THE NORTH...OR EVEN SOME FREEZING
DRIZZLE WITH MOST OF THE SATURATION AT TEMPS ABOVE -10C. FOR NOW
WON/T MENTION FREEZING DRIZZLE...BUT POTENTIAL IS THERE. TEMPS
WILL BE A BIT COLDER WED WITH LOW LEVEL CAA AND NORTHERLY WINDS
INCREASING A BIT.
FOR THU/THU NIGHT...COOL AIR ADVECTION CONTINUES AND THERE COULD
BE SOME FLURRIES/LOW CLOUDS ON THU WITH A WEAK UPPER TROUGH. FOR NOW
HAVE KEPT IT DRY WITH TEMPS SLOWLY COOLING FROM NORTH TO SOUTH AND
THE COLUMN SLOWLY DRYING OUT.
LONG TERM (FRI-MONDAY NIGHT)...
MODELS IN FAIR AGREEMENT WITH THE EXTENDED UPPER AIR PATTERN AS
LARGE SCALE POSITIVE PNA DEVELOPS ACROSS THE CONUS FOR THE WEEKEND.
THE RESULT ACROSS THE NORTHERN PLAINS REMAINS A DRY FORECAST FRI TO
SUNDAY WITH NW 500MB FLOW AND INCREASING 1000 TO 500MB THICKNESSES
AS RIDGING WORKS INTO THE REGION. A POTENT WAVE IS EXPECTED TO
DE-AMPLIFY THE RIDGING AND ENTER INTO THE AREA SUNDAY NIGHT INTO
MONDAY...HENCE THE CHC POPS. MODELS TEND TO BREAK DOWN THE POSITIVE
PNA TOO QUICKLY AND HAVE SLOWED THE ARRIVAL OF THE SYSTEM FOR A
COUPLE RUNS ALREADY. WOULDN/T BE SURPRISED IF THE TREND CONTINUES.
NEAR NORMAL TEMPS EXPECTED THROUGH THE PERIOD.
&&
.FGF WATCHES/WARNINGS/ADVISORIES...
ND...NONE.
MN...NONE.
&&
$$
GODON
AREA FORECAST DISCUSSION
NWS GREENVILLE-SPARTANBURG SC
119 PM EST TUE FEB 26 2013
.SYNOPSIS...
STRONG LOW PRESSURE WILL MOVE FROM INTO THE GREAT LAKES AREA TODAY
WHILE DRAGGING A COLD FRONT ACROSS OUR AREA. BREEZY CONDITIONS AND
COLDER TEMPERATURES WILL SETTLE IN BEHIND THE FRONT THROUGH
THURSDAY. ON FRIDAY ANOTHER FRONT WILL APPROACH THE AREA FROM THE
WEST AND MOVE THROUGH THE AREA OVER THE WEEKEND.
&&
.NEAR TERM /THROUGH TONIGHT/...
900 AM UPDATE...BACK EDGE OF HEAVIER PCPN WILL BE NEAR DRY SLOT
EVIDENT ON WV IMAGERY. SFC OBS AND RADAR INDICATING SOME SCATTERED
SHOWERS ARE PRESENT BEHIND THE BACK EDGE. ALSO NOTING RAP SOUNDINGS
WHICH STILL SHOW INSTABILITY ABOVE WARM NOSE UNTIL MIDLEVEL COLD
ADVECTION GETS GOING THIS AFTN. THUS MAINTAINED CHC POPS BEHIND THE
SOLID PCPN SHIELD AS WELL AS THUNDER WORDING FROM MRNG PACKAGE.
REVISED TEMP TRENDS TO SLOW WARMING A BIT OVER THE NRN PIEDMONT
WHERE LIGHT ICE ACCUM STILL OCCURRING...PUTTING TEMPS MORE IN LINE
WITH 06Z NAM WHICH VERIFIED BETTER EARLIER THIS MRNG. ALLOWED WINTER
HEADLINES TO EXPIRE OVER THE SW MTNS WHERE TEMPS HAVE MOSTLY WARMED
ABV 0C...BUT EXTENDED BY ONE HOUR THE WINTER STORM WRNG UP NORTH AND
ALSO THE FZRA ADVY FOR THE FOOTHILLS THAT PREVIOUSLY EXPIRED AT 14Z.
PREV DISCUSSION...AS OF 400 AM...THE COMPLEX OCCLUDED LOW AND WEDGE
COMBO SYSTEM IS LIVING UP TO AND SURPASSING EXPECTATIONS A LITTLE
THIS MORNING. THE COOLING ACROSS THE NC MTNS AND THE AMOUNT OF
PRECIP EXPECTED THE NEXT SEVERAL HRS WILL COMBINE TO GIVE A GOOD
AMOUNT OF -FZRA ACROSS THE CENTRAL MTNS AND HIGHER ELEV OF THE SRN
FOOTHILLS...ALONG WITH THE ESCARPMENT AREA NEAR THE SC/NC BORDER.
STILL EVALUATING THE NRN MTNS AND HIGH ELEV NRN FOOTHILLS FOR A
POSSIBLE WARNING UPGRADE...BUT FOR NOW WILL COUNT OF THE PRECIP/ICE
ACCUMS REMAINING THE HIGHEST ACROSS THE AREAS TO THE SOUTH WHERE THE
BEST LIFT AND ISENT OMEGA EXIST. ALSO...WILL ADD A FREEZING RAIN
ADVISORY FOR AREAS EAST OF THE MTNS ACROSS THE NRN/SRN FOOTHILLS AND
THE NC PIEDMONT WEST OF THE I-77 CORRIDOR.
THE MODELS ARE DOING AN ADEQUATE JOB WITH THE DYNAMICS OF THIS
SYSTEM THROUGH THE NEAR TERM AND GIVE GOOD CONFIDENCE WITH THE
WARMING TAKING OVER THE LLVLS BY 14Z OR SO AND CHANGING THE MAJORITY
OF LOCALES TO ALL -RA. HOWEVER...THERE MAY BE SOME LINGERING POCKETS
OF -FZRA ACROSS ISOL MTN VALLEYS THROUGH LATE MORNING. HAVE NOTICED
THE WETBULB FREEZING ZONE EXPANDING IN COVERAGE THIS MORNING INTO
THE UPSTATE AND THREATENING AREAS AROUND CLT AND THE I-77. THIS WILL
BE MONITORED FOR A POSSIBLE FZRA ADVISORY INCLUSION.
THE HIGH WIND WARNING AND ADVISORY ACROSS THE WRN MTNS STILL LOOKS
GOOD. THE P/GRAD IS SHOWING AN 8 MB P/GRAD THROUGH 12Z AND THE LLJ
IS PROGGED TO STRENGTHEN TO AROUND 55 KTS ACROSS THE HIGHER
ELEVATIONS THROUGH THIS TIME AS WELL. NO ADJUSTMENTS WILL BE MADE TO
THIS PRODUCT.
THE DRY SLOT WORKS IN THIS AFTERNOON AND CLOUDS PRECIP WILL BE QUICK
TO END ACROSS THE SW/RN ZONES...HOWEVER THE NE/RN SECTIONS WILL HOLD
ONTO PRECIP THROUGH THE AFTERNOON. THE WEDGE ALSO BEGINS TO BREAK
DOWN AROUND NOON AND A WELL DEFINED TMB WILL DEVELOP WHILE A TRIPLE
POINT LOW TRAVERSES OVERHEAD. THUS...THUNDER HAS BEEN MAINTAINED IN
THE GRIDS BEGINNING ISOL AROUND 17Z AND CHANCE TSTMS DURING THE
AFTERNOON ACROSS THE ERN THIRD OF THE CWFA. NOT EXPECTING REALLY
DEEP OR OVERLY ORGANIZED CONVECTION...BUT WITH BULK SHEAR LEVELS
AROUND 70 KTS THERE COULD BE SOME WIND ISSUES WITH SOME OF THESE
LINES.
&&
.SHORT TERM /WEDNESDAY THROUGH THURSDAY NIGHT/...
AS OF 330 AM EST TUESDAY...AS WE HEAD TOWARD MARCH...IT LOOKS LIKE
WE ARE HEADING TOWARD WINTER...AT LEAST OVER THE NC MTNS NEAR THE TN
BORDER. WEDNESDAY WILL SEE THE UPPER LOW MOVING SLOWLY OVER THE
UPPER OH VALLEY. THIS WILL KEEP THE FLOW MORE SW TO W ACROSS THE
WESTERN CAROLINAS DURING MOST OF THE DAY DELAYING THE ARRIVAL OF THE
REALLY COLD AIR. HOWEVER...A LARGE VORT LOBE SHOULD PINWHEEL AROUND
THE UPPER LOW AND CROSS THE FCST AREA DURING THE LATE AFTERNOON AND
EARLY EVENING. THAT FEATURE WILL BE THE VANGUARD OF THE COOLER AIR
AND WILL TURN THE FLOW MORE NORTHWESTERLY WEDNESDAY NIGHT. THIS WILL
SERVE TO CRANK UP THE NW FLOW SNOW MAKING MACHINE. POP WAS RAMPED UP
INTO THE LIKELY RANGE NEAR THE TN BORDER AND KEPT THERE THROUGH
THURSDAY NIGHT AS FLOW AND MOISTURE REMAIN VERY FAVORABLE FOR THE
PRODUCTION OF SNOW SHOWERS. ACCUMULATIONS COULD END UP BEING
SIGNIFICANT IN THE FAVORABLE UPSLOPE AREAS NEAR THE TN BORDER...BUT
THE DURATION WILL BE LONG ENOUGH THAT OUR WARNING CRITERIA MIGHT NOT
BE MET. WILL NOT ISSUE A WATCH FOR THIS EVENT BECAUSE OF THE
DURATION V. ACCUM ISSUE...BUT PLAN TO HIT IT HARD IN THE HWO. SOME
OF THE SNOW SHOWERS SHOULD REACH A BIT DEEPER INTO THE MTNS THURSDAY
NIGHT WHEN MOISTURE IS A BIT DEEPER. E OF THE MTNS...IT SEEMS
DOUBTFUL THAT ANY SHOWERS WILL BREACH CONTAINMENT AND SURVIVE E OF
THE BLUE RIDGE. INSTEAD...IT SHOULD BE DRY WITH A PARTLY
CLOUDY/MOSTLY CLEAR SKY...WITH TEMPS A BIT ABOVE NORMAL WEDNESDAY
AND THEN BELOW NORMAL THURSDAY AS THE COLDER AIR REALLY TAKES HOLD.
&&
.LONG TERM /FRIDAY THROUGH TUESDAY/...
AS OF 300 AM EST TUESDAY...AS THE DEEP LOW PRESSURE SYSTEM MOVES
FARTHER OFFSHORE FROM LONG ISLAND ON FRIDAY...LOW LEVEL MOISTURE
WILL CONTINUE TO BANK UP AGAINST THE TN AND NC BORDER. THE
NORTHWEST FLOW FROM ACROSS KY AND TN WILL CONTINUE TO PRODUCE
UPSLOPE SNOW SHOWERS FRIDAY AND FRIDAY NIGHT. MEDIUM RANGE MODELS
AGREE ON A DISTURBANCE ROUNDING THE BASE OF THE 500MB TROUGH ON
SATURDAY WITH BROADER ENHANCEMENT OF MOSTLY LIGHT PRECIP ACROSS OUR
REGION. GFS HAS A 536 DECIMETER LOW CENTERED OVER THE SMOKIES AT 18Z
SATURDAY WITH A TENTH OR LESS 6-HOUR PRECIP EXTENDING OVER TO CLT.
THE NEW ECMWF CLOSES A LOW ON FRIDAY AS IT CROSSES TN AND THEN OPENS
IT ONCE IT IS OVER THE NC MTNS AT 18Z SATURDAY. THEREFORE THE TIMING
IS IN SYNC. ECMWF PRECIP IS VERY LIGHT...0.01 TO 0.03 IN 6 HOURS.
AS THIS FEATURE PASSES EAST OF OUR AREA...PRECIP ENDS EAST OF THE
MTNS SATURDAY NIGHT AND SUNDAY AND LIGHT UPSLOPE SNOW SHOWERS COME
TO AN END SUNDAY EVENING ALONG THE NC AND TN BORDER. MOST OF THE
GUIDANCE TONIGHT HAS INCREASING TEMPS BY ONE TO 3 DEGREES...BUT WITH
THE DEPTH OF THE TROUGH AND ALL OTHER LOGICAL METEOROLOGY IT SEEMS
SENSIBLE TO EVEN LOWER TEMPS A DEGREE OR TWO OVER THE WEEKEND.
AFTER THE TROUGH MOVES OFF THE EAST COAST SUNDAY NIGHT...A SHALLOW
RIDGE BUILDS OVER OUR AREA FOR MONDAY RESULTING IN SLIGHTLY HIGHER
THICKNESSES AND A BIT MILDER UNDER PLENTY OF SUNSHINE. EVEN WITH
THIS SLIGHT WARM UP...TEMPS WILL STILL BE ABOUT 8 TO 10 DEGREES
BELOW NORMAL TO START NEXT WEEK.
&&
.AVIATION /18Z TUESDAY THROUGH SUNDAY/...
AT KCLT...MAJORITY OF PRECIPITATION HAS MOVED NORTH AND EAST OF THE
AIRFIELD. COLD WEDGE HAS HELD STRONG AND SFC BASED INSTABILITY NO
LONGER APPEARS TO BE A CONCERN. SOME CONVECTIVELY ENHANCED SHOWERS
ARE PRESENT ON RADAR ACROSS THE REGION BUT NO LIGHTNING STRIKES HAVE
BEEN RECORDED. INDEED A FEW SHOWERS ARE LIKELY TO MOVE THROUGH THIS
AFTERNOON POSSIBLY BRINGING IFR VSBY BUT NO THUNDER EXPECTED. IFR
CIG SHOULD HOLD ON FOR SEVERAL HOURS...ONCE SHOWER ACTIVITY
DIMINISHES CIGS MAY IMPROVE TO LOW MVFR. WINDS NELY UNDER THE WEDGE.
ONCE COLD FRONT PUSHES IN THIS EVENING THE WEDGE WILL ERODE...WINDS
WILL SWING TO SOUTHWEST AND VFR CIGS ARRIVE THEN SCATTER. SOME
POTENTIAL FOR FOG TO DEVELOP LATE TONIGHT GIVEN MOIST SOILS AND
FAIRLY MOIST LLVL PROFILES...BUT GUIDANCE KEEPS VFR VSBY THROUGH
DAYBREAK.
ELSEWHERE...WIDESPREAD SHRA WILL CONTINUE NORTH OF KCLT...AFFECTING
KHKY THIS AFTN. PASSING BANDS OF CONVECTIVE SHOWERS MAY BRIEFLY
AFFECT THE OTHER SITES AS WELL...WITH A SLIGHT CHANCE OF THUNDER.
THE SHRA MAY BRING IFR VSBY AT THEIR HEAVIEST. SHOWERS DIMINISH BY
LATE AFTN...WITH ALL TERMINALS BEING DRY OVERNIGHT. MOSTLY IFR CIGS
LOOK TO HOLD ON UNTIL COLD FRONT PUSHES WEDGE OUT OF THE PICTURE
LATE THIS AFTN IN OUR WEST AND THIS EVENING EAST. VFR STRATUS SHOULD
FILL IN BEHIND THE FRONT BUT MAY SCATTER LATE. NE WINDS UNDER THE
WEDGE WILL TURN SOUTH TO SOUTHWEST BEHIND THE FRONT.
OUTLOOK...DRY AIR ADV AND CLEARING SKIES WILL CONTINUE WED NIGHT
WITH VFR CONDS EXPECTED THROUGH THURSDAY EAST OF THE MOUNTAINS. SOME
POTENTIAL EXISTS FOR MVFR ACROSS THE NC MTNS WITH SNOW SHOWERS MID
TO LATE WEEK.
CONFIDENCE TABLE...
18-24Z 00-06Z 06-12Z 12-18Z
KCLT HIGH 100% HIGH 90% HIGH 100% HIGH 98%
KGSP HIGH 94% HIGH 88% HIGH 98% HIGH 98%
KAVL HIGH 96% HIGH 89% MED 69% HIGH 94%
KHKY HIGH 87% HIGH 88% MED 73% HIGH 95%
KGMU MED 76% HIGH 88% HIGH 98% HIGH 98%
KAND MED 72% HIGH 91% MED 65% HIGH 95%
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...WIND ADVISORY UNTIL 6 PM EST THIS EVENING FOR NCZ033-048>052-
058-059.
SC...NONE.
&&
$$
SYNOPSIS...PAT
NEAR TERM...SBK/WIMBERLEY
SHORT TERM...PM
LONG TERM...DEO
AVIATION...WIMBERLEY
AREA FORECAST DISCUSSION
NWS MEMPHIS TN
318 PM CST TUE FEB 26 2013
.DISCUSSION...
IT HAS BEEN A COLD...CLOUDY...DAMP...WINDY DAY ACROSS THE
MIDSOUTH. TEMPERATURES ARE GENERALLY 12 TO 18 DEGREES COLDER THAN
THIS TIME YESTERDAY...GENERALLY IN THE LOW 40S. STEADY 15-20 MPH
WIND ALONG WITH HIGH MOISTURE HAS MADE IT FEEL EVEN COLDER.
UNFORTUNATELY NO RELIEF IN THE WAY. NO SUBSTANTIAL WARMING IS
EXPECTED OVER THE NEXT SEVERAL DAYS.
TONIGHT...CLOUDS WILL LINGER ACROSS MOST OF THE AREA. AS THE UPPER
LEVEL LOW WHICH BROUGHT US THE PRECIPITATION YESTERDAY AND TODAY
SHIFTS INTO THE OHIO VALLEY...A VERY WEAK SHORTWAVE RIDGE WILL
SHIFT ACROSS THE MIDSOUTH. PORTIONS OF NORTH MISSISSIPPI AND EAST
CENTRAL ARKANSAS MAY SEE SOME TEMPORARY CLEARING...BUT IT WILL BE
SHORT LIVED AS A STRONG VORT MAX TRACKS OUT OF OKLAHOMA ENHANCING
CLOUD COVER AREA WIDE ONCE AGAIN.
WEST FLOW WILL TRANSITION TO NORTHWEST FLOW ON WEDNESDAY. THE
STORM TRACK WILL BE TO OUR NORTHWEST WEDNESDAY...BUT CLOSE ENOUGH
TO KEEP SKIES CLOUDY ACROSS MOST OF THE AREA. HIGHS MAY GET INTO
THE LOW 50S IN NORTH MISSISSIPPI...BUT THE NORTHERN HALF OF THE
MIDSOUTH WHERE CLOUDS WILL BE MORE ABUNDANT...WILL STRUGGLE TO GET
OUT OF THE 40S.
A BROAD POSITIVELY TILTED LONGWAVE TROUGH WILL DIG INTO THE
SOUTHERN PLAINS THURSDAY INTO FRIDAY. A CUTOFF LOW WILL DEVELOP
AND TRACK FROM EAST KANSAS TO NEAR THE MEMPHIS AREA FRIDAY INTO
SATURDAY MORNING. SUFFICIENT MOISTURE SHOULD BE IN PLACE AHEAD OF
THIS SYSTEM RESULTING IN RAIN SHOWERS THURSDAY...MOST LIKELY IN
WEST TENNESSEE...NORTHEAST ARKANSAS AND THE MISSOURI BOOTHEEL. AS
THE LOW GETS CLOSER AND TEMPERATURES DROP THURSDAY
NIGHT...SHOWERS MAY CHANGE OVER TO SNOW. RAIN OR SNOW LOOKS LIKE A
GOOD BET FRIDAY ACROSS THE NORTHERN HALF OF THE MIDSOUTH. WE MAY
SEE SEVERAL PHASE CHANGES FROM SNOW TO RAIN AND BACK TO SNOW ON
FRIDAY...ESPECIALLY IN PORTIONS OF TENNESSEE. WILL MAINTAIN LIGHT
SNOW AREA WIDE FRIDAY NIGHT INTO SATURDAY AS THE LOW TRACKS
DIRECTLY OVER THE MIDSOUTH. WE HAVE LOWS SATURDAY MORNING 1-4
DEGREES BELOW FREEZING...AND HIGHS AROUND 40...SO ONCE AGAIN
PRECIPITATION WILL LIKELY CHANGE PHASES...POSSIBLY SEVERAL TIMES.
THE TROUGH AXIS WILL SHIFT INTO CENTRAL TENNESSEE AND ALABAMA
SUNDAY NIGHT LIKELY MARKING THE END OF OUR PRECIPITATION.
HOWEVER...DEPENDING ON THE EXACT TRACK OF THE UPPER LOW...WE COULD
SEE ADDITIONAL WRAP AROUND SHOWERS SATURDAY NIGHT. GRADUAL
IMPROVING CONDITIONS ARE EXPECTED SUNDAY INTO NEXT WEEK...BUT
TEMPERATURES WILL REMAIN SEASONABLY COLD. HIGHS MONDAY ARE ONLY
EXPECTED TO BE IN THE MIDDLE 50S AT THE WARMEST LOCATIONS WITH THE
COOLER AREAS POSSIBLY STILL IN THE 40S.
&&
.AVIATION...
18Z TAF SET
MVFR CIGS WILL REMAIN OVER THE MIDSOUTH THROUGH AT LEAST 7-8Z AS
UPPER LOW PUSHES INTO THE OHIO VALLEY. LATEST RUC KEEPS CIGS
LONGER WHICH WOULD NOT BE SURPRISED IF THIS OCCURS AS ANOTHER
SHORTWAVE WILL ROTATE INTO THE MIDSOUTH AROUND 12Z. A FEW SHRAS
WILL BE POSSIBLE THIS AFTERNOON ACROSS THE AREA THUS WILL
CONTINUE WITH VCSH WORDING IN THE TAF. SOME SNOWFLAKES COULD MIX IN
AT KJBR AS COLDER AIR FILTERS INTO THE AREA. STRONG SW WINDS OF
12-20 KTS WITH HIGHER GUSTS WILL CONTINUE THROUGH EARLY THIS
EVENING. SPEEDS WILL GRADUALLY BEGIN DIMINISHING AFTER 1-3Z.
SPEEDS WILL PICK BACK UP AROUND 15Z AS DIRECTION BECOMES MORE W OR
NW.
KRM
&&
.PRELIMINARY POINT TEMPS/POPS...
MEM 34 50 34 46 / 10 10 10 10
MKL 33 47 33 45 / 10 10 10 20
JBR 33 47 33 45 / 10 10 10 20
TUP 34 54 34 48 / 10 10 10 10
&&
.MEG WATCHES/WARNINGS/ADVISORIES...
AR...NONE.
MO...NONE.
MS...NONE.
TN...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS MEMPHIS TN
1118 AM CST TUE FEB 26 2013
.UPDATE... /ISSUED 1049 AM CST TUE FEB 26 2013/
FORECAST LOOKS TO BE IN GOOD SHAPE. LIGHT RAIN IS FALLING ACROSS
MUCH OF THE MIDSOUTH RESULTING IN MINIMAL ACCUMULATION. RAIN WILL
CONTINUE THIS AFTERNOON...BUT LIKELY BECOME CONFINED TO THE
NORTHERN HALF OF THE CWA. LOWERED AFTERNOON POPS SLIGHTLY. DESPITE
RAIN ON RADAR...ACCUMULATING RAIN IS QUESTIONABLE.
OTHERWISE...BREEZY AND COOL CONDITIONS WILL CONTINUE
TODAY...ABUNDANT MOISTURE AND LACK OF SUNSHINE WILL MAKE
CONDITIONS FEEL EVEN COLDER.
&&
.DISCUSSION... /ISSUED 310 AM CST TUE FEB 26 2013/
CURRENTLY SURFACE LOW CENTER WAS LOCATED JUST NORTH OF JONESBORO
WITH AN OCCLUDED FRONT SWUNG SOUTHEAST FROM DYERSBURG TENNESSEE TO
JUST EAST OF TUPELO MISSISSIPPI. THE UPPER LEVEL CENTER SEEN ON
WATER VAPOR IMAGERY WAS LOCATED NEAR LITTLE ROCK. WINDS TO THE
EAST OF THE FRONT WERE SOUTHEAST AROUND 10 KTS...WITH RADAR
SHOWING A BAND OF RAIN SLOWLY DIMINISHING IN COVERAGE AND
INTENSITY. BEHIND THE FRONT...WINDS VEER MORE SOUTHWESTERLY WITH
DRY CONDITIONS. TEMPERATURES ACROSS THE MIDSOUTH AS OF 3 AM RANGED
FROM THE MID 40S TO MID 50S. DUE TO A DRIER RADAR TRENDS HAVE
UPDATED THE CURRENT FORECAST TO LOWER RAIN CHANCES BETWEEN 3 AND 6
AM THIS MORNING.
FOR TODAY MODELS ARE IN VERY GOOD AGREEMENT THAT THE MIDSOUTH WILL
REMAIN CLOUDY AND COOL WITH SCATTERED SHOWERS REDEVELOPING AS THE
UPPER LOW TRACKS SLOWLY TO THE LOWER OHIO VALLEY. BEST CHANCE FOR
ADDITIONAL MEASURABLE RAINFALL WILL BE ACROSS THE NORTH. SOUTHWEST
WINDS WILL INCREASE BEFORE NOON WITH GUSTS TO NEAR 30MPH. NOT MUCH
CHANGE IS ANTICIPATED TONIGHT WITH THE EXCEPTION OF SLIGHTLY DRIER
AIR MOVING IN FROM THE WEST. CAA WILL KEEP TEMPERATURES FAIRLY
STEADY IN THE 40S...TO LOW 50S FOR HIGHS. LATER TONIGHT FEEL THAT
STRATOCUMULUS CLOUD DECK WILL LINGER OVER THE REGION...KEEPING
TEMPERATURES ABOVE FREEZING.
THE UPPER LEVEL LOW WILL MOVE UP THE OHIO RIVER ON WEDNESDAY AND
SLOWLY BEGIN TO FILL. EXTENDING FROM THE LOW WILL BE HIGHLY POSITIVE
TILTED TROUGH BACK WEST TO OKLAHOMA. THIS PATTERN WILL CONTINUE TO
KEEP THE MIDSOUTH CLOUDY AND COOL...WITH A SLIGHT CHANCE FOR
BRIEF RAIN SHOWER OVER THE NORTH. TEMPERATURES WILL RUN ABOUT TEN
DEGREES BELOW NORMAL. THE TROUGH WILL PUSH SOUTHEAST THROUGH THE
AREA WEDNESDAY NIGHT WILL A SLIGHT SURFACE REFLECTION SHIFTING
WINDS MORE NORTHWESTERLY. FROM THIS...THE UPPER LEVEL PATTERN
WILL BECOME MORE MERIDIONAL...SO HAVE SLIGHTLY LOWERED THE CURRENT
HIGHS FOR THURSDAY...AS THIS WILL BE THE START OF AN UPCOMING
COLD SNAP FOR THE ENTIRE EASTERN HALF OF THE U.S.
THE BRUNT OF THE COLD AIR WILL ARRIVE ON FRIDAY AND PERSIST
THROUGH SATURDAY WITH 925MB TEMPERATURES FALLING FROM -2C TO -8C.
THIS IS IN RESPONSE TO A MORE INTENSE SHORTWAVE DROPPING INTO THE
BACKSIDE OF THE EASTERN TROUGH. THE GFS AND EURO ARE IN AGREEMENT
THAT A NEWLY FORMED CLOSED LOW WILL EMERGE FROM THIS SHORTWAVE
RIGHT OVERHEAD. MOISTURE WITH THIS DEVELOPMENT FOR NOW APPEARS
STARVED...SO HAVE KEPT POPS LOW. HOWEVER...TEMPERATURES WILL
SUPPORT A LIGHT RAIN AND SNOW MIX DURING THE DAY NORTH OF THE
TENNESSEE AND MISSISSIPPI STATE LINE...WITH ALL SNOW FRIDAY NIGHT.
MINOR ACCUMULATIONS WILL BE POSSIBLE. NOT MUCH CHANGE IS EXPECTED
ON SATURDAY WITH HIGHS EVEN A FEW DEGREES COLDER AND THE CONTINUED
CHANCE FOR A SNOW FLURRY. WITH THAT BEING SAID ONE COULD EITHER
SAY MARCH WILL BE COMING IN LIKE A LION...OR IS THIS THE FIRST
WEEKEND IN JANUARY?
EXTENDED PERIOD...SOME MODERATION IN TEMPERATURES WILL BE SEEN ON
SUNDAY AND MONDAY...BUT THEY WILL STILL BE BELOW NORMAL. NEXT
STORM WILL DIVE SOUTHEAST FROM THE UPPER HIGH PLAINS. LOW LEVEL
SOUTH WINDS WILL BRING BETTER MOISTURE TO THE MIDSOUTH MONDAY
NIGHT AND TUESDAY. THUS THIS CLIPPER TYPE EVENT WILL BRING A BRIEF
INCREASE IN TEMPERATURES AND RAIN CHANCES TO THE REGION.
JAB
&&
.AVIATION...
18Z TAF SET
MVFR CIGS WILL REMAIN OVER THE MIDSOUTH THROUGH AT LEAST 7-8Z AS
UPPER LOW PUSHES INTO THE OHIO VALLEY. LATEST RUC KEEPS CIGS
LONGER WHICH WOULD NOT BE SURPRISED IF THIS OCCURS AS ANOTHER
SHORTWAVE WILL ROTATE INTO THE MIDSOUTH AROUND 12Z. A FEW SHRAS
WILL BE POSSIBLE THIS AFTERNOON ACROSS THE AREA THUS WILL
CONTINUE WITH VCSH WORDING IN THE TAF. SOME SNOWFLAKES COULD MIX IN
AT KJBR AS COLDER AIR FILTERS INTO THE AREA. STRONG SW WINDS OF
12-20 KTS WITH HIGHER GUSTS WILL CONTINUE THROUGH EARLY THIS
EVENING. SPEEDS WILL GRADUALLY BEGIN DIMINISHING AFTER 1-3Z.
SPEEDS WILL PICK BACK UP AROUND 15Z AS DIRECTION BECOMES MORE W OR
NW.
KRM
&&
&&
.PRELIMINARY POINT TEMPS/POPS...
MEM 49 36 50 35 / 40 10 10 10
MKL 49 35 47 34 / 40 10 10 10
JBR 48 35 47 34 / 60 10 10 10
TUP 48 36 54 35 / 30 10 10 10
&&
.MEG WATCHES/WARNINGS/ADVISORIES...
AR...NONE.
MO...NONE.
MS...NONE.
TN...NONE.
&&
$$
AREA FORECAST DISCUSSION...UPDATED
NWS MILWAUKEE/SULLIVAN WI
1219 PM CST TUE FEB 26 2013
.UPDATE...
PRECIP WILL MOVE INTO THE CWA SHORTLY. RADAR TRENDS INDICATE THE
LEADING EDGE REACHING KENOSHA AIRPORT BETWEEN 1830Z AND 1900Z AND
MILWAUKEE AND JANESVILLE ABOUT AN HOUR TO AN HOUR AND A HALF
LATER. EROSION ON THE LEADING EDGE SLOWED THINGS DOWN A BIT
EARLIER TODAY AND BIT MORE EROSION IS POSSIBLE AS IT HEADS INTO
DRY AIR. SO FAR THE HRRR HAS BEEN PRETTY ACCURATE WITH THE LEADING
EDGE...MAYBE A BIT SLOW.
EXPECTING A MIX OF RAIN...SLEET...AND SNOW AT FIRST IN THE FAR
SOUTHEAST. THINKING THE PRECIP WILL CHANGE OVER TO SNOW RELATIVELY
QUICKLY...WITHIN A HOUR OR TWO...AS THE LOW AND MID LEVELS
SATURATE. THINKING WE WILL SEE MODERATE TO HEAVY SNOW AS SOON AS
SNOW BEGINS.
ADDED IOWA AND DANE COUNTIES TO THE ADVISORY AS THE SOUTHERN
PORTIONS OF THE COUNTIES COULD CERTAINLY REACH THE 3 TO 5 INCH
MARK. ALSO EXTENDED THE ADVISORY ACROSS THE BOARD TO NOON
TOMORROW. SNOW IS EXPECTED TO CONTINUE INTO WEDNESDAY MORNING AND
WILL BECOME MORE DRY WITH TIME...ALLOWING FOR MORE BLOWING AND
DRIFTING.
&&
.AVIATION/18Z TAFS/...
EXPECTING CONDITIONS TO DETERIORATE QUICKLY AS PRECIP MOVES IN.
LOOKS LIKE PRECIP WILL BEGIN NO LATER THAN 19Z AT ENW AND AROUND
20Z AT MKE. EXPECTING TO SEE A MIX OF RAIN AND SNOW AND POSSIBLY
SLEET AT MKE AND ENW. DON/T EXPECT THIS TO LAST LONG AS AIR AND
LOWER AND MID LEVELS SATURATES. THINKING UES WILL ONLY GET
SNOW...BUT A VERY BRIEF MIX IS POSSIBLE. MSN WILL LIKELY ONLY SEE
SNOW.
18Z OBS SHOW FEW/SCT LOW CLOUDS ALREADY MOVING IN AT MSN
AND UES...A BIT EARLIER THAN EXPECTED. GENERALLY EXPECTING LOW
CLOUDS TO QUICKLY DEVELOP AS PRECIP MOVES IN AND THINGS SATURATE.
CONCERNED THAT CEILINGS COULD BE EVEN LOWER LOOKING AT THE LATEST
NORTHERN ILLINOIS OBS...IN THE BELOW ALTERNATE MINIMUMS RANGE.
ALSO...COULD SEE MODERATE OR EVEN HEAVY SNOW AS SOON AS SNOW
BEGINS. VISIBILITIES COULD EASILY REACH THE BELOW ALTERNATE
MINIMUMS RANGE.
EXPECTING IFR TO BELOW ALTERNATE MINIMUM VISIBILITIES AND/OR
CEILINGS TO PERSIST THROUGH THE DAY WEDNESDAY AS THE LOW PRESSURE
LINGERS OVER THE EASTERN GREAT LAKES REGION.
&&
.MARINE...
A GALE WARNING REMAINS IN EFFECT THROUGH WEDNESDAY NIGHT AS
STRONG LOW PRESSURE TRACKS FROM NORTHEAST ARKANSAS TO LOWER
MICHIGAN BY WEDNESDAY MORNING. BRISK EAST TO NORTHEAST WINDS WILL
GUST TO GALE FORCE AND THEN TURN NORTHERLY ON WEDNESDAY. HIGH
WAVES ARE EXPECTED.
&&
.PREV DISCUSSION... /ISSUED 329 AM CST TUE FEB 26 2013/
TODAY AND TONIGHT...FORECAST CONFIDENCE IS HIGH.
MODERATE 250 MB UPPER LEVEL DIVERGENCE LIFTS NORTH FROM ILLINOIS
EARLY THIS MORNING. THIS SEEN BY RAPIDLY THICKENING CLOUDS. THIS
UPPER LEVEL DIVERGENCE CONTINUES THROUGH THE NIGHT...AS IT
WEAKENS.
GOOD MID LEVEL WARM TROWAL LIFTS NORTH ACROSS SOUTHERN WISCONSIN
TODAY. STRONG 700 MB UPWARD MOTION LIFTS NORTH BUT WEAKENS AS IT
REACHES SOUTHERN WISCONSIN. HOWEVER THIS LIFT CONTINUES THROUGH
THE NIGHT.
MODERATE 850 MB MOISTURE CONVERGENCE THIS AFTERNOON BEFORE
WEAKENING A LITTLE. NEVER THE LESS MODELS AGREE ON PUSHING
PRECIPITATION NORTHWARD INTO FAR SOUTHERN WISCONSIN THIS
AFTERNOON, THEN ACROSS MUCH OF THE FORECAST AREA TONIGHT. MAIN
FORECAST CONCERN IS WITH AMOUNTS. MOST MODELS HAVE TRENDED TOWARD
THE HIGHER NAM...ALTHOUGH IT IS STILL HIGHER NEAR LAKE MICHIGAN
THAN THE REST. IT APPEARS THE CONSENSUS PRECIPITATION IS VERY
REASONABLE, GIVEN THE GFS MAY BE TOO LOW.
STRONG AND GUSTY NORTHEAST WINDS ARE EXPECTED AS THE LOW PRESSURE
APPROACHES NORTHERN INDIANA AND SOUTHERN LOWER MICHIGAN.
THE EASTERLY WINDS WILL KEEP LOW LEVEL DRY AIR IN PLACE OVER
SOUTHERN WI...WHICH WILL LEAD TO A DELAY IN PRECIP ON THE NORTH
SIDE OF THE LOW MAKING IT INTO SOUTHERN WI. HOWEVER THIS WILL ALSO
AID IN EVAPORATIVE COOLING WHICH COMBINED WITH DYNAMIC COOLING
SHOULD RESULT IN A SNOW EVENT...WITH A POSSIBLE RAIN/SNOW MIXTURE
AT ONSET.
WILL PUSH SNOW AMOUNTS TO NEAR WINTER STORM WARNING CRITERIA IN
THE FAR SOUTHEAST...INCLUDING MILWAUKEE TO KENOSHA. IF THE HIGHER
PRECIP TRENDS CONTINUE ON LATER MODEL RUNS A WARNING MAY BE
NEEDED...GIVEN THE STRONG WINDS AND WET HEAVY SNOW.
WEDNESDAY THROUGH THURSDAY NIGHT...FORECAST CONFIDENCE IS HIGH.
SHORT TERM MODELS ARE IN DECENT AGREEMENT WITH TAKING SURFACE LOW
FROM FAR NORTHEAST INDIANA/FAR NORTHWEST OHIO SLOWLY EASTWARD
WEDNESDAY AND WEDNESDAY NIGHT...REACHING NEW ENGLAND BY 12Z
THURSDAY. ASSOCIATED 500MB LOW SHIFTS SLOWLY EASTWARD IN A SIMILAR
FASHION...BEING NEARLY VERTICALLY STACKED WITH THE SURFACE LOW.
VARIOUS VORTICITY MAXIMA AT 500MB ROTATE CYCLONICALLY THROUGH THE
AREA WEDNESDAY INTO WEDNESDAY NIGHT. LITTLE IF ANY LOW TO MID
LEVEL FRONTOGENESIS RESPONSE DURING THIS TIME...WITH WEAK Q VECTOR
CONVERGENCE IN THE LOW LEVELS.
AREA FORECAST SOUNDINGS FROM NAM/GFS SHOWING WEAK UPWARD VERTICAL
MOTION DURING THIS TIME...BUT AIR COLUMN IS SATURATED IN THE LOW
TO MID LEVELS FOR MOST OF WEDNESDAY INTO WEDNESDAY
EVENING...BEFORE DRYING OUT FROM THE TOP DOWN LATER WEDNESDAY
NIGHT. WINDS REMAIN GUSTY OUT OF THE NORTH WEDNESDAY WITHIN TIGHT
PRESSURE GRADIENT. GUSTS OF 30 KNOTS PLUS APPEAR POSSIBLE ON AREA
FORECAST SOUNDINGS...ESPECIALLY IN THE NORTHEAST HALF OF THE
AREA...AND NEAR THE LAKE. THIS MAY LEAD TO SOME BLOWING SNOW.
WINDS REMAIN SOMEWHAT GUSTY WEDNESDAY NIGHT.
SHORT TERM MODELS CONTINUE TO SHOW QPF OF GENERALLY 0.08 TO 0.15
INCHES WEDNESDAY...WITH A FEW HUNDREDTHS MORE WEDNESDAY NIGHT.
SNOW TO LIQUID RATIOS WILL BE LOW WEDNESDAY WITH HIGHS AROUND OR
JUST ABOVE FREEZING...WHICH SHOULD KEEP SNOW ACCUMULATIONS AT AN
INCH OR LESS. CIPS ANALOGS DO SHOW 1 TO 2 INCHES POSSIBLE
WEDNESDAY. RAISED POPS TO CATEGORICAL FOR WEDNESDAY...WITH LOWER
POPS WEDNESDAY NIGHT.
THURSDAY AND THURSDAY NIGHT THEN HAVE A WEAK 500MB RIDGE MOVING
INTO THE REGION ON THE SHORT TERM MODELS. AT THE SURFACE...AREA
REMAINS BETWEEN LOW PRESSURE WELL EAST OF THE REGION...AND HIGH
PRESSURE WELL NORTH OF THE REGION. PRESSURE GRADIENT DOES RELAX
DURING THIS TIME...SO WINDS SHOULD DECREASE IN MAGNITUDE. AREA
FORECAST SOUNDINGS FROM NAM/GFS DRY OUT EXCEPT BELOW LOW LEVEL
INVERSION AROUND 3000 FEET ABOVE GROUND LEVEL. THUS...QPF FROM
GFS/CANADIAN SEEMS OVERDONE VERSUS DRY NAM/ECMWF. WENT DRY FOR
THURSDAY.
HOWEVER...LAKE EFFECT SNOW POTENTIAL INCREASES THURSDAY
NIGHT...AS LOW LEVEL WINDS REMAIN NORTHEAST AND DELTA T VALUES
INCREASE TO 12 TO 13 DEGREES CELSIUS. THIS IS BORDERLINE FOR LAKE
EFFECT SNOW. STILL...LOW LEVELS REMAIN MOIST BELOW INVERSION AND
TAP SHALLOW DENDRITE GROWTH ZONE. LAKE EFFECT SNOW FLOW CHART ONLY
SHOWS MINOR ACCUMULATIONS UP TO AN INCH. WILL KEEP POPS FOR
THURSDAY NIGHT NEAR THE LAKE. CIPS ANALOGS SHOW LIGHT
ACCUMULATIONS THURSDAY NIGHT. TEMPERATURES WILL REMAIN NEAR OR
JUST ABOVE SEASONAL NORMALS.
FRIDAY THROUGH MONDAY...FORECAST CONFIDENCE IS MEDIUM.
GFS/ECMWF IN GENERAL AGREEMENT WITH FEATURES THROUGH MOST OF THE
WEEKEND...WITH DIFFERENCES FOR SUNDAY NIGHT/MONDAY. GFS MAINTAINS
LAKE EFFECT SNOW POTENTIAL FRIDAY INTO SATURDAY NIGHT NEAR THE
LAKE. FORECAST SOUNDINGS SHOW DELTA T VALUES REMAINING AROUND 13
DEGREES CELSIUS WITH NORTHEAST LOW LEVEL FLOW. POPS MAY BE NEEDED
NEAR THE LAKE IN LATER FORECASTS. THE ECMWF IS SHOWING LIGHT QPF
NEAR THE SHORE AS WELL DURING PARTS OF THIS PERIOD.
THE REST OF THE AREA WILL SEE QUIET WEATHER WITH A HIGH PRESSURE
RIDGE MOVING INTO THE REGION. DRY AIRMASS WILL LIMIT EFFECT OF
PASSING 500MB SHORTWAVE TROUGH. TEMPERATURES SHOULD REMAIN NEAR OR
JUST BELOW SEASONAL NORMALS.
GFS THEN BRINGS LOW PRESSURE FROM SOUTH DAKOTA INTO NORTHWEST
IOWA SUNDAY NIGHT AND MONDAY...SPREADING QPF WITHIN WARM AIR
ADVECTION/FRONTOGENESIS OVER THE REGION. ECMWF KEEPS THIS FEATURE
FURTHER TO THE WEST DURING THIS TIME...AND HAS THE AREA DRY. GIVEN
THE DIFFERENCES...WILL USE CONSENSUS POPS AND TEMPERATURES FOR
SUNDAY NIGHT AND MONDAY.
AVIATION/12Z TAFS/...
CEILINGS WILL CONTINUE TO LOWER TODAY WITH MAINLY VFR CONDITIONS
INTO THE EARLY AFTERNOON. THEN WITH PRECIPITATION SPREADING NORTH
MVFR CONDITIONS WILL LOWER TO IFR AND SOME LIFR AS STRONG LOW
PRESSURE MOVES INTO NORTHERN INDIANA LATE TONIGHT.
EAST WINDS WILL INCREASE THIS MORNING. WINDS WILL QUITE STRONG OUT
OF THE NORTHEAST ON LATER TODAY AND TONIGHT.
MARINE...
A GALE WARNING IS IN EFFECT THROUGH WEDNESDAY NIGHT AS STRONG LOW
PRESSURE TRACKS FROM NORTHEAST ARKANSAS TO LOWER MICHIGAN BY
WEDNESDAY MORNING. BRISK EAST TO NORTHEAST WINDS WILL GUST TO GALE
FORCE AND THEN TURN NORTHERLY ON WEDNESDAY. HIGH WAVES ARE
EXPECTED.
&&
.MKX WATCHES/WARNINGS/ADVISORIES...
WI...WINTER WEATHER ADVISORY FROM 3 PM THIS AFTERNOON TO NOON CST
WEDNESDAY FOR WIZ062>072.
WINTER WEATHER ADVISORY FROM 6 PM THIS EVENING TO NOON CST
WEDNESDAY FOR WIZ052-059-060.
LM...GALE WARNING UNTIL 4 AM CST THURSDAY FOR LMZ643>646.
&&
$$
UPDATE...MEB
TODAY/TONIGHT AND AVIATION/MARINE...HENTZ
WEDNESDAY THROUGH MONDAY...WOOD
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
1156 AM CST TUE FEB 26 2013
.SHORT TERM...THIS AFTERNOON THROUGH WEDNESDAY
1154 AM CST TUE FEB 26 2013
THE 26.12Z MODELS CONTINUED THE TREND OF THE 26.06Z MODELS AND
SHIFTED THE DEFORMATION SNOW BAND A BIT FURTHER NORTH INTO
SOUTHWEST WISCONSIN AND NORTHEAST IOWA. THE GFS CONTINUED TO BE
THE FURTHEST NORTH. MEANWHILE THE 26.06Z ARW AND NMM...AND THE
26.12Z RAP...NAM...GEM...AND HRRR SHOW THAT THIS BAND WILL A BIT
FURTHER SOUTH. OVERALL...THINK THAT THE GFS IS A BIT TOO FAR
NORTH...SO TRENDED THE FORECAST TOWARD THE OTHER MODEL RUNS.
OVERALL THE QPF LOOKS TO BE IN THE 0.25 TO 0.50 INCH RANGE SOUTH
OF A RICHLAND CENTER TO OELWEIN IOWA LINE FROM MID-AFTERNOON TODAY
THROUGH WEDNESDAY MORNING. COBB DATA WOULD SUGGEST RATIOS RANGING FROM
10-15 TO 1. THIS WOULD RESULT IN 3 TO 6 INCH SNOW TOTALS FOR THE
SOUTHERN AND EASTERN PORTIONS OF BOTH FAYETTE AND CLAYTON COUNTIES
IN NORTHEAST IOWA...AND GRANT COUNTY IN SOUTHWEST WISCONSIN.
IN ADDITION TO THE SNOW...NORTH WINDS AT 10 TO 20 MPH MAY CAUSE
AREAS OF BLOWING AND DRIFTING SNOW ACROSS THESE AREAS FROM TONIGHT
IN WEDNESDAY MORNING.
DUE TO THIS SNOW AND BLOWING SNOW...WENT WITH A WINTER WEATHER
ADVISORY FROM 3 PM THIS AFTERNOON THROUGH 12 PM WEDNESDAY FOR
FAYETTE AND CLAYTON COUNTIES IN NORTHEAST IOWA...AND GRANT COUNTY
IN SOUTHWEST WISCONSIN.
LIGHT SNOW MAY CONTINUE INTO WEDNESDAY AFTERNOON...BUT ADDITIONAL
ACCUMULATIONS WILL BE LESS THAN AN INCH.
.LONG TERM...FRIDAY THROUGH MONDAY
325 AM CST TUE FEB 26 2013
25.00Z MEDIUM RANGE MODELS IN RATHER GOOD AGREEMENT WITH EACH OTHER
AND THEIR PREVIOUS RUNS FRI INTO SUNDAY. THIS WITH TROUGHING OVER
EASTERN NOAM AND RIDGING OVER WESTERN NOAM...AND THE THE UPPER
MIDWEST IN BETWEEN UNDER NORTHWEST TO NORTH FLOW ALOFT. FRI-SUN
CONTINUES TO TREND DRY. TEMPS COOLER FOR FRI/SAT UNDER NORTHERLY
FLOW AND COOLER 925-850MB TEMPS ALOFT. QUESTIONS ARISE AS TO HOW
QUICKLY SOME LOW LEVEL WARM ADVECTION RETURNS FOR SUN...WITH GFS
FASTER/MORE ROBUST THAN ECMWF/GEM. BY MON MODELS DIFFER ON THE
STRENGTH/TRACK OF THE NEXT STRONGER SHORTWAVE/SFC LOW AFTER IT
CROSSES THE NORTHERN ROCKIES INTO THE NORTHERN PLAINS. LITTLE
BETWEEN MODEL AND RUN-TO-RUN CONSISTENCY ON THIS DAY 7 FEATURE...
WHICH IS NOT UNEXPECTED WITH THE PATTERN LOOKING TO BREAK DOWN THE
WESTERN NOAM RIDGE INTO EARLY NEXT WEEK. FOR NOW A SMALL -SN
CHANCE WITH SEASONABLE TEMPS PER THE MODEL/ENSEMBLE CONSENSUS LOOKS
REASONABLE ON MONDAY. THE MODEL/ENSEMBLE CONSENSUS DATA SET ALSO
LOOKS TO HAVE DAYS 4-6 WELL TRENDED AT THIS TIME.
&&
.AVIATION...THROUGH 18Z WEDNESDAY
1154 AM CST TUE FEB 26 2013
A DEFORMATION BAND OF SNOW WILL BE SEEN ACROSS SOUTHWEST WISCONSIN
AND NORTHEAST IOWA FROM THIS AFTERNOON THROUGH WEDNESDAY MORNING.
THIS SNOW WILL RDUCE VISIBILITIES TO LESS THAN A MILE.
BOTH THE TAF SITES WILL BE ON THE NORTHERN EDGE OF THIS SNOW BAND.
AT KLSE...THE GFS QUICKLY SATURATES THE SOUNDING BY 27.06Z.
MEANWHILE THE NAM DOES NOT SHOW THIS OCCURRING UNTIL 27.12Z. THE
RAP WAS A GOOD COMPROMISE BETWEEN THESE TWO...SO WENT WITH THAT
AND HAVE THE SNOW DEVELOPING BETWEEN 27.07Z AND 27.09Z. THIS SNOW
WILL REDUCE THE VISIBILITIES TO 2 MILES AND CEILINGS TO MVFR.
AT KRST...IT LOOKS LIKE DRY AIR BELOW 10K FEET WILL KEEP THIS TAF
SITE DRY...THUS...KEPT THIS SITE WITH VFR CEILINGS AND VISIBILITIES.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
1137 AM CST TUE FEB 26 2013
WI...WINTER WEATHER ADVISORY FROM 3 PM THIS AFTERNOON TO NOON CST
WEDNESDAY FOR WIZ061.
MN...NONE.
IA...WINTER WEATHER ADVISORY FROM 3 PM THIS AFTERNOON TO NOON CST
WEDNESDAY FOR IAZ029-030.
&&
$$
SHORT TERM...BOYNE
LONG TERM....RRS
AVIATION...BOYNE